CN111378129A - Polyamide-imide resin, polyamide-imide resin varnish, optical film, and flexible display device - Google Patents

Abstract

Provided are a polyamideimide resin, a polyamideimide resin varnish, an optical film, and a flexible display device, which can produce an optical film having a high elastic modulus while maintaining a high total light transmittance, and which is excellent in stability in the varnish state. The polyamideimide resin has at least a structural unit represented by formula (a) derived from a tetracarboxylic acid compound, a structural unit represented by formula (b) derived from a dicarboxylic acid compound, and a structural unit represented by formula (c) derived from a diamine compound, contains a structural unit (a1) represented by formula (1) wherein Y in formula (a) is a structural unit derived from a tetracarboxylic acid compound, and has a weight average molecular weight of 330,000 or more. Y represents a tetravalent organic group, Z and X represent divalent organic groups, R^cRepresents a hydrogen atom or a chemical bond, R^aRepresents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, R^aThe hydrogen atom contained in the compound may be substituted by a halogen atom, and n represents an integer of 0 to 2; denotes a bond.

Description

Polyamide-imide-based resin, polyamide-imide-based resin varnish, optical film and flexible Sexual display device

technical field

The present invention relates to a polyamide-imide-based resin, a polyamide-imide-based resin varnish and an optical film including the resin, and a flexible display device including the optical film.

Background technique

Currently, display devices such as liquid crystal display devices and organic EL display devices are widely used not only in televisions but also in various applications such as mobile phones and smart watches. Conventionally, glass has been used as a front panel of such a display device. However, although glass is highly transparent and exhibits high hardness depending on the type, on the other hand, it is very rigid and easily broken, and therefore it is difficult to use it as a material for a front panel of a flexible display device.

Therefore, the utilization of polymer materials has been studied as a material to replace glass. A front panel formed of a polymer material is expected to be used in various applications because it easily exhibits flexibility. As one of the polymer materials having flexibility, for example, an optical film using a polyamideimide-based resin has been studied (Patent Documents 1 and 2).

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Publication No. 2015-521686

Patent Document 2: Japanese Patent Laid-Open No. 2018-119132

SUMMARY OF THE INVENTION

The problem to be solved by the invention

Although an optical film using a polyamideimide-based resin has been studied, there are still demands for further improvement of the optical properties and elastic modulus of the optical film. In addition, when producing an optical film containing a polyamide-imide-based resin, a step of applying a varnish obtained by dissolving the resin or a precursor of the resin in a solvent is performed. According to the structure of the polyamide-imide-based resin Depending on the type of monomer, the stability of the varnish may be insufficient, gel may be generated in the varnish, and the film formability and optical properties of the optical film may be deteriorated.

Therefore, an object of the present invention is to provide a polyamide-imide-based resin that can produce an optical film having a high elastic modulus while maintaining a high total light transmittance and has excellent stability in a varnish state.

means of solving problems

The inventors of the present application have conducted intensive studies in order to solve the above-mentioned problems, and as a result found that a polyamide-imide-based resin having at least a specific structural unit and having a weight average molecular weight in a specific range can easily maintain the overall performance of the obtained optical film. The present invention has been completed by improving the elastic modulus while improving the light transmittance, and having excellent stability in a varnish state.

That is, the present invention includes the following preferred embodiments.

[1] A polyamideimide-based resin having at least a structural unit represented by the formula (a) derived from a tetracarboxylic acid compound, a structural unit represented by the formula (b) derived from a dicarboxylic acid compound, and a diamine compound derived The polyamideimide-based resin of the structural unit represented by the formula (c), wherein Y in the formula (a) is represented by the structural unit (a1) represented by the formula (1) as the structural unit derived from the tetracarboxylic acid compound , and the polyamide-imide-based resin has a weight average molecular weight of 330,000 or more in terms of polystyrene.

[In formula (a), Y represents a tetravalent organic group,

In formula (b), Z represents a divalent organic group,

In formula (c), X represents a divalent organic group,

R ^c independently of each other represents a hydrogen atom or a chemical bond,

*indicates chemical bond]

[In formula (1), R ^a independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms,

The hydrogen atoms contained in R ^a can be replaced by halogen atoms independently of each other,

n represents an integer from 0 to 2,

*indicates chemical bond]

[2] The polyamideimide-based resin according to the aforementioned [1], which contains the structural unit (b1) represented by the formula (2) as a structural unit derived from a dicarboxylic acid compound, and which contains the formula (3) The structural unit (c1) represented is a structural unit derived from a diamine compound.

[In formula (2), Z ¹ represents a divalent aromatic group which may have a substituent,

*indicates chemical bond]

[In formula (3), X ¹ represents a divalent aromatic group which may have a substituent,

R ^c independently of each other represents a hydrogen atom or a chemical bond,

*indicates chemical bond]

[3] The polyamideimide-based resin according to the above [2], wherein X ¹ in the formula (3) is represented by the formula (4).

[In formula (4), R ^b independently represents an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms,

The hydrogen atoms contained in R ^b independently of each other may be replaced by halogen atoms,

r independently represents an integer from 1 to 4,

*indicates chemical bond]

[4] The polyamideimide-based resin according to any one of the above [1] to [3], which contains a structural unit (b2) in which Z in the formula (b) is represented by the formula (5) as a A structural unit derived from a dicarboxylic acid compound, and/or, a structural unit (c2) in which X in the formula (c) is represented by the formula (5) is included as a structural unit derived from a diamine compound, and/or, and the formula ( Y in a) is a structural unit (a2) represented by formula (6) as a structural unit derived from a tetracarboxylic acid compound.

[In formula (5), Ar ¹ independently represents a divalent aromatic group which may have a substituent,

V represents -O-, diphenylmethylene, linear, branched or alicyclic divalent hydrocarbon group having 1 to 12 carbon atoms, -SO ₂ -, -S-, -CO- or -N(R ¹² )-, where the hydrogen atoms contained in the hydrocarbon group may be independently substituted by halogen atoms,

R ¹² represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms which may be substituted by a halogen atom,

m represents an integer of 1 to 3, wherein, when m is 2 or 3, there are a plurality of V which may be the same or different from each other,

*indicates chemical bond]

[In formula (6), Ar ² independently represents a trivalent aromatic group which may have a substituent,

s represents an integer from 0 to 2,

Ar ¹ , V and * are as defined for Ar ¹ , V and * in formula (5), where, when s is 2, there are a plurality of V and Ar ¹ which may be the same or different from each other]

[5] The polyamideimide-based resin according to the above [4], wherein the formula (5) and the formula (6) are represented by the formula (7).

[In formula (7), R ¹ independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms, The hydrogen atoms contained in R ¹ independently of each other may be substituted by halogen atoms,

R ^* means ^R1 or chemical bond,

* denotes chemical bond,

V represents -O-, diphenylmethylene, linear, branched or alicyclic divalent hydrocarbon group having 1 to 12 carbon atoms, -SO ₂ -, -S-, -CO- or -N(R ¹² )-, where the hydrogen atom contained in the hydrocarbon group may be independently substituted by a halogen atom, and R ¹² represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms which may be substituted by a halogen atom ]

[6] The polyamideimide-based resin according to the above [5], wherein the formula (7) is represented by the formula (7') or the formula (7").

[In formula (7'), R ^* represents a hydrogen atom or a chemical bond, and * represents a chemical bond]

[In formula (7"), * represents a chemical bond]

[7] The polyamideimide-based resin according to any one of the above [1] to [6], wherein the formula (1) is represented by the formula (1').

[* indicates chemical bond]

[8] A polyamideimide-based resin varnish comprising the polyamideimide-based resin according to any one of the above [1] to [7] and a solvent.

[9] An optical film comprising the polyamideimide-based resin according to any one of the above [1] to [7].

[10] A flexible display device including the optical film according to [9] above.

[11] The flexible display device according to the above [10], further comprising a touch sensor.

[12] The flexible display device according to the above [10] or [11], further comprising a polarizing plate.

effect of invention

The polyamideimide-based resin of the present invention can provide an optical film having a high elastic modulus while maintaining a high total light transmittance. In addition, the polyamideimide-based resin of the present invention has good stability in a varnish state.

Detailed ways

Hereinafter, embodiments of the present invention will be described in detail. In addition, the scope of the present invention is not limited to the embodiment described here, and various modifications can be made without departing from the gist of the present invention.

The polyamideimide-based resin of the present invention has at least a structural unit represented by formula (a) derived from a tetracarboxylic acid compound, a structural unit represented by formula (b) derived from a dicarboxylic acid compound, and a formula derived from a diamine compound. (c) The polyamideimide-based resin of the structural unit represented by,

[In formula (a), Y represents a tetravalent organic group,

In formula (b), Z represents a divalent organic group,

In formula (c), X represents a divalent organic group,

R ^c independently of each other represents a hydrogen atom or a chemical bond,

*indicates chemical bond]

Wherein, the structural unit represented by the formula (1) in the formula (a) is included as the structural unit derived from the tetracarboxylic acid compound,

[In formula (1), R ^a independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms,

The hydrogen atoms contained in R ^a can be replaced by halogen atoms independently of each other,

n represents an integer from 0 to 2,

*indicates chemical bond]

The polyamide-imide-based resin has a weight average molecular weight of 330,000 or more in terms of polystyrene. In this specification, the structural unit in which Y in the formula (a) is represented by the formula (1) is also referred to as a "structural unit (a1)".

The polyamide-imide-based resin of the present invention has at least a structural unit represented by the formula (a) derived from a tetracarboxylic acid compound (hereinafter, also referred to as "structural unit (a)") and a formula (b) derived from a dicarboxylic acid compound. ) represented by the structural unit (hereinafter, also referred to as "structural unit (b)") and the structural unit represented by the formula (c) derived from the diamine compound (hereinafter, also referred to as "structural unit (c)"), including Y in the formula (a) is represented by the structural unit (a1) of the formula (1) as the structural unit (a) derived from the tetracarboxylic acid compound. The polyamide-imide-based resin of the present invention generally has a plurality of structural units (a), a plurality of structural units (b), a plurality of structural units (c), and optionally a plurality of other structural units. In the present specification, the so-called polyamide-imide-based resin of the present invention includes a structural unit (a1) in which Y in the formula (a) is represented by the formula (1) as a structural unit (a) derived from a tetracarboxylic acid compound, and is It means that among the plurality of structural units (a) contained in the polyamideimide-based resin, at least some of the structural units (a) are structural units (a1) in which Y in the formula (a) is represented by the formula (1). The above-mentioned descriptions are also applicable to the other descriptions in this specification. In addition, the chemical bond in a formula (a) - a formula (c) is a chemical bond which couple|bonded with the adjacent structural unit.

The polyamideimide-based resin of the present invention has at least a structural unit (a), a structural unit (b), and a structural unit (c). Here, the structural unit (a) derived from the tetracarboxylic acid compound and the structural unit (a) derived from the diamine compound The structural unit (c) usually forms an imide bond represented by the formula (D), and is contained in the polyamideimide-based resin, and the structural unit (b) derived from the dicarboxylic acid compound and the structural unit derived from the diamine compound ( c) The amide bond represented by the formula (E) is formed and contained in the polyamideimide-based resin.

[In formula (D), Y represents a tetravalent organic group,

X represents a divalent organic group,

*indicates chemical bond]

[In formula (E), Z and X independently represent a divalent organic group,

*indicates chemical bond]

In addition, the moiety having Y and four carbonyl groups in the formula (D) corresponds to the structural unit (a) derived from the tetracarboxylic acid compound, and the moiety having Z and two carbonyl groups in the formula (E) corresponds to the moiety derived from the tetracarboxylic acid compound. In the structural unit (b) of the dicarboxylic acid compound, the moiety having X and an amino group in the formula (D) and formula (E) corresponds to the structural unit (c) derived from the diamine compound. In addition, in the part corresponding to the structural unit (c) derived from the diamine compound in the formula (D) and the formula (E), X representing a divalent organic group is bound by one of the chemical bonds In the amino group, the chemical bond indicated by * on the other side is bonded to the adjacent structural unit. When the structural units represented by the formula (D) and the formula (E) appear repeatedly, the chemical bond represented by * bonded to the adjacent structural unit is bonded to the amino moiety in the formula (D) or the formula (E). Therefore, the moiety having X and an amino group in formula (D) and formula (E) can be said to be a moiety corresponding to the structural unit (c) derived from the diamine compound.

The polyamideimide-based resin of the present invention contains, as the structural unit (a) derived from the tetracarboxylic acid compound, a structural unit (a1) in which Y in the formula (a) is represented by the formula (1). In this case, the polyamideimide-based resin of the present invention has a structural unit (D) in which Y is represented by the formula (1). * in formula (D) and formula (E) represents a chemical bond to an adjacent structural unit.

The polyamide-imide-based resin of the present invention has at least a structural unit (a1) derived from a tetracarboxylic acid compound in which Y in formula (a) is represented by formula (1), a structural unit (b) derived from a dicarboxylic acid compound, and a structural unit (c) derived from a diamine compound, and may further have a structural unit derived from a tetracarboxylic acid compound other than the above, and/or a structural unit derived from a monomer other than the above. Specifically, the polyamideimide-based resin of the present invention has at least one or two or more structural units (a1) and 1 derived from the tetracarboxylic acid compound represented by the formula (1) in which Y in the formula (a) is represented by the formula (1). One or two or more kinds of the structural unit (b) derived from a dicarboxylic acid compound, and one or two or more kinds of the structural unit (c) derived from a diamine compound, may further have in the formula (a) in addition to these Y does not belong to one type or two or more types of structural units derived from tetracarboxylic acid compounds (for example, structural unit (a2) described later) of formula (1), and/or derived from tetracarboxylic acid compounds, dicarboxylic acid compounds, and A structural unit of one or two or more other monomers other than the diamine compound (hereinafter, also referred to as a structural unit (d)).

The polyamideimide-based resin of the present invention contains, as the structural unit (a) derived from the tetracarboxylic acid compound, a structural unit (a1) in which Y in the formula (a) is represented by the formula (1). By making the polyamideimide-based resin contain the structural unit (a1), the structural unit represented by the formula (1) will be contained in the polyamideimide-based resin. The structural unit represented by the formula (1) is a structure with high rigidity, and a part having rigidity will be included in the skeleton of the polyamideimide-based resin. As a result, surprisingly, it became easy to improve the elastic modulus and total light transmittance of the obtained optical film.

In addition, by making the polystyrene-equivalent weight average molecular weight of the polyamide-imide-based resin of the present invention 330,000 or more, the elastic modulus and optical properties of the optical film to be obtained can be easily improved, and the polyamide-containing polyamide can be improved. Stability of varnish of imide resin. In addition, in this specification, the varnish containing a polyamideimide-type resin is also called "resin varnish". When the polystyrene-equivalent weight average molecular weight of the polyamide-imide-based resin is less than 330,000, it is difficult to suppress the gelation of the resin varnish over time, and as a result, the film formability of the resin varnish at the time of optical film production decreases, and /Or the optical properties of the resulting optical film are degraded, which is obvious. Although the reason for this is not clear, it is thought that in the polyamideimide-based resin containing the structural unit (a1) in which Y in the formula (a) is represented by the formula (1), it is easy to fill between the adjacent polymer chains with the Since it is a part of the structural unit represented by Formula (1), the interaction between the molecules of the polyamideimide-based resin tends to improve. Moreover, it is thought that the amino group and the carboxyl group which can exist in the terminal part of a polyamideimide-type resin are easy to form a hydrogen bond between polymer chains. When the polystyrene-equivalent weight-average molecular weight of the polyamide-imide resin is less than 330,000, the structural unit represented by the formula (1) and the amino and carboxyl groups that may exist in the terminal portion cause the mutual interaction between the polymer chains Since the action becomes too high, it is considered that the varnish tends to gel with the passage of time. It should be noted that the present invention is not limited in any way by the above-mentioned mechanism.

The polyamide-imide-based resin of the present invention has a weight average molecular weight of 330,000 or more in terms of polystyrene, and it is easy to improve the stability of the varnish and the optical properties, elastic modulus, surface hardness, and bending resistance of the optical film. From the viewpoint of 400,000 or more, more preferably 420,000, still more preferably 440,000 or more, particularly preferably 460,000 or more, it is easy to improve the solubility of the polyamideimide-based resin in the solvent, and it is easy to improve the elongation of the optical film From the viewpoint of property and workability, it is preferably 1,000,000 or less, more preferably 800,000 or less, still more preferably 700,000 or less, and particularly preferably 600,000 or less. The weight average molecular weight can be calculated|required by the standard polystyrene conversion by performing GPC measurement, for example, and can be calculated|required by the method as described in an Example.

The method for adjusting the weight average molecular weight of the polyamideimide-based resin is not particularly limited. For example, in order to obtain the polyamidoimide-based resin, when a tetracarboxylic acid compound, a dicarboxylic acid compound, and a diamine compound are copolymerized, the preferred Yes, by adjusting the ratio of the molar amount of the diamine compound to about 1.0 with respect to the total molar amount of the tetracarboxylic acid compound and the dicarboxylic acid compound, a polyamidoimide having a weight average molecular weight in the desired range described above is produced. Amine resin. Specifically, the ratio of the molar amount of the diamine compound when the total molar amount of the tetracarboxylic acid compound and the dicarboxylic acid compound is 1 (the molar amount of the diamine compound/(the total amount of the tetracarboxylic acid compound and the dicarboxylic acid compound) molar amount), hereinafter, this ratio is also referred to as "amine ratio") is preferably 0.95 or more, more preferably 0.97 or more, still more preferably 0.98 or more, particularly preferably 0.99 or more, from the ease of polyamideimide resin From the viewpoint of adjusting the weight average molecular weight of α to a preferred range, it is preferably 1.05 or less, more preferably 1.03 or less, still more preferably 1.02 or less, and particularly preferably 1.01 or less.

The polyamideimide-based resin of the present invention contains, as a structural unit derived from a tetracarboxylic acid compound, a structural unit (a1) in which Y in the formula (a) is represented by the formula (1).

[In formula (1), R ^a independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms,

The hydrogen atoms contained in R ^a can be replaced by halogen atoms independently of each other,

n represents an integer from 0 to 2,

*indicates chemical bond]

The polyamideimide-based resin of the present invention may have one kind of structural unit (a1) represented by formula (1) in which Y in formula (a) is represented by formula (1), or may have Y in formula (a) represented by formula (1). of two or more structural units (a1).

R ^a in formula (1) independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and R The hydrogen atoms contained in ^a may be replaced by halogen atoms independently of each other. In a preferred embodiment of the present invention, R ^a is preferably a hydrogen atom from the viewpoint of easily improving the total light transmittance and elastic modulus of the optical film obtained by using the polyamideimide-based resin.

Examples of the alkyl group having 1 to 12 carbon atoms include linear, branched, or alicyclic alkyl groups having 1 to 12 carbon atoms. Examples of linear, branched, or alicyclic alkyl groups having 1 to 12 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, 2-methylbutyl, 3-methylbutyl, 2-ethylpropyl, n-hexyl, n-heptyl, n-octyl, tert-octyl, n-nonyl, n-decyl base, cyclopentyl, cyclohexyl, etc. The alkyl group having 1 to 12 carbon atoms may be a linear alkyl group, a branched alkyl group, or an alicyclic alkyl group including an alicyclic hydrocarbon structure. The number of carbon atoms of the alkyl group having 1 to 12 carbon atoms is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 to 3. The above-mentioned alkyl group having 1 to 12 carbon atoms may be at least one hydrogen atom independently replaced by a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a hydroxyl group. , or a group obtained by substitution of a carboxyl group. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned. Here, when the alkyl group having 1 to 12 carbon atoms is substituted with a substituent containing carbon atoms (for example, the alkyl group having 1 to 4 carbon atoms), the number of carbon atoms of the alkyl group having 1 to 12 carbon atoms is does not include the number of carbon atoms contained in the substituent. For example, a group obtained by substituting the above-mentioned alkyl group having 1 to 12 carbon atoms with an alkyl group having 1 to 4 carbon atoms has an alkyl group having 1 to 12 carbon atoms as the main chain, and the alkane A group obtained by substituting at least one hydrogen atom of the group with an alkyl group having 1 to 4 carbon atoms. When the number of carbon atoms in the alkyl part of the main chain is 1 to 12, the number of carbon atoms in the entire alkyl group may be larger than 12. In the case of a group in which the number of carbon atoms as a whole alkyl group does not exceed 12, a group obtained by substituting an alkyl group having 1 to 12 carbon atoms with an alkyl group having 1 to 4 carbon atoms A group is a group also included in the definition of a branched alkyl group having 1 to 12 carbon atoms.

Examples of the alkoxy group having 1 to 12 carbon atoms include methoxy group, ethoxy group, propyloxy group, isopropyloxy group, n-butoxy group, isobutoxy group, and tert-butoxy group. , pentyloxy, hexyloxy, cyclohexyloxy, heptyloxy, octyloxy, nonyloxy and decyloxy, etc. The alkyl moiety and/or the alkylene moiety in the alkoxy group having 1 to 12 carbon atoms may be linear, branched, or alicyclic. The number of carbon atoms of the alkoxy group having 1 to 12 carbon atoms is preferably 1 to 6, more preferably 1 to 4, and still more preferably 1 to 3. The above-mentioned alkoxy group having 1 to 12 carbon atoms may have at least one hydrogen atom independently replaced by a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, A group obtained by substitution of a hydroxyl group or a carboxyl group. As a halogen atom, the atom described above is mentioned. Here, when the alkoxy group having 1 to 12 carbon atoms is substituted with a substituent containing carbon atoms, the number of carbon atoms in the alkoxy group having 1 to 12 carbon atoms does not include the carbon contained in the substituent. the number of atoms.

As a C6-C12 aryl group, a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a biphenyl group, etc. are mentioned, for example. The number of carbon atoms of the aryl group having 6 to 12 carbon atoms is preferably 6 or 10 or 12. The above-mentioned aryl group having 6 to 12 carbon atoms may be at least one hydrogen atom independently replaced by a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a hydroxyl group. , or a group obtained by substitution of a carboxyl group. As a halogen atom, the atom described above is mentioned. Here, when the aryl group having 6 to 12 carbon atoms is substituted with a substituent containing carbon atoms, the number of carbon atoms of the aryl group having 6 to 12 carbon atoms does not include the carbon atoms contained in the substituent. number.

The hydrogen atoms contained in R ^a may be substituted by halogen atoms independently of each other. As a halogen atom, the atom described above is mentioned.

n in the formula (1) represents an integer of 0 to 2, and is preferably 0 or 1 from the viewpoint of easily improving the total light transmittance and elastic modulus of the optical film obtained by using the polyamideimide-based resin, More preferably, it is 0.

* in formula (1) represents a chemical bond bonded to a moiety derived from a carboxyl group (eg, an imide moiety) in a structural unit derived from a tetracarboxylic acid compound. In the present specification, the term "tetracarboxylic acid compound" may be a compound having four carboxyl groups, an acid halide of the compound, a carboxylic acid ester, and/or a carboxylic dianhydride obtained by dehydration condensation of two adjacent carboxyl groups. From the viewpoint of easiness of polymerization during synthesis, the tetracarboxylic acid compound is preferably tetracarboxylic dianhydride.

For example, when the tetracarboxylic acid compound is a tetracarboxylic dianhydride, the tetracarboxylic acid compound providing the structural unit (a1) in which Y in the formula (a) is represented by the formula (1) is represented by the formula (8).

[In formula (8), R ^a and n are as defined in formula (1)]

In the polyamide-imide-based resin of the present invention, the amount of the structural unit (a1) in which Y in the formula (a) is represented by the formula (1) is based on all the structural units contained in the polyamide-imide-based resin. Preferably it is 2-45 mol%, More preferably, it is 5-40 mol%, More preferably, it is 10-40 mol%, Especially preferably, it is 15-35 mol%. When the quantity of a structural unit (a1) is more than the said minimum, it becomes easy to improve the elastic modulus of an optical film. Moreover, when the quantity of a structural unit (a1) is below the said upper limit, it becomes easy to improve the total light transmittance of an optical film. Here, in this specification, all the structural units contained in the polyamide-imide-based resin mean all the monomer units contained in the polyamide-imide-based resin. In addition, the amount of the structural unit (a1) and all structural units contained in the polyamideimide-based resin can be measured using ¹ H-NMR, for example, or can be calculated from the charge ratio of the raw materials.

The formula (1) is preferably represented by the formula (1').

[* indicates chemical bond]

In addition, formula (1') corresponds to the structure in which R ^a in formula (1) is a hydrogen atom, and n is 0.

The polyamideimide-based resin of the present invention has at least a structural unit (b) derived from a dicarboxylic acid compound in addition to the structural unit (a1) in which Y in the formula (a) is represented by the formula (1). , and the structural unit (c) derived from the diamine compound. The polyamideimide-based resin may have one kind of structural unit (b), or may have two or more kinds of structural units (b). Moreover, the polyamide-imide-type resin may have 1 type of structural unit (c), and may have 2 or more types of structural units (c).

In the polyamide-imide-based resin of the present invention, the amount of the structural unit (b) derived from the dicarboxylic acid compound is preferably 5 to 70 mol % based on all the structural units contained in the polyamide-imide-based resin, More preferably, it is 10 to 65%, and even more preferably, it is 20 to 60 mol%. When the quantity of a structural unit (b) is more than the said minimum, it becomes easy to improve the solubility of resin in a solvent, and it becomes easy to improve the stability of a varnish. Moreover, when the quantity of a structural unit (b) is below the said upper limit, it becomes easy to raise an elastic modulus.

In the polyamideimide-based resin of the present invention, when the total amount of the structural unit (a) derived from the tetracarboxylic acid compound and the structural unit (b) derived from the dicarboxylic acid compound is taken as 100 mol %, the amount derived from the diamine compound is 100 mol %. The amount of the structural unit (c) is preferably 95 to 105 mol %, more preferably 97 to 103 mol %, further preferably 98 to 102 mol %, and particularly preferably 99 to 101 mol %. When the amount of the structural unit (c) is outside the above-mentioned range, the molecular weight is not easily increased, and the stability of the varnish is likely to decrease.

In the polyamide-imide-based resin of the present invention, the structural unit (b) derived from the dicarboxylic acid compound is represented by the formula (b).

[In formula (b), Z represents a divalent organic group,

*indicates chemical bond]

Here, * in formula (b) is a chemical bond connected to the structural unit (c) derived from the diamine compound which is usually adjacent to the structural unit derived from the dicarboxylic acid compound in the polyamideimide-based resin of the present invention . The structural unit (b) forms, for example, an amide bond represented by the above-mentioned formula (E).

Z in the formula (b) is a divalent organic group, preferably a hydrocarbon group having 1 to 8 carbon atoms, a hydrocarbon group having 1 to 8 carbon atoms substituted by fluorine, or a hydrocarbon group having 1 to 6 carbon atoms that may be substituted by fluorine. An alkoxy group, or a divalent organic group having 4 to 40 carbon atoms substituted by a fluorine-substituted alkoxy group having 1 to 6 carbon atoms, more preferably a hydrocarbon group that may be substituted with 1 to 8 carbon atoms , a fluorine-substituted hydrocarbon group with 1 to 8 carbon atoms, an alkoxy group with 1 to 6 carbon atoms, or a fluorine-substituted alkoxy group with 1 to 6 carbon atoms, having a cyclic structure A divalent organic group with 4 to 40 carbon atoms. As a cyclic structure, an alicyclic structure, an aromatic ring, and a heterocyclic structure are mentioned. As Z, formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) can be mentioned. A divalent organic group obtained by replacing two non-adjacent hydrogen atoms in the chemical bond of the group represented by the formula (29) and a divalent chain hydrocarbon group having 6 or less carbon atoms, as the heterocyclic structure of Z , a divalent organic group having a thiophene ring skeleton can be exemplified.

From the viewpoint of easily suppressing the yellowness of the optical laminate (reducing the YI value), two groups in which non-adjacent two of the chemical bonds of the groups represented by the formulae (20) to (29) are replaced with hydrogen atoms are preferred. A valent organic group, and a divalent organic group having a thiophene ring skeleton. In one embodiment of the present invention, the structural unit (b) contained in the polyamideimide-based resin may contain one type of organic group as Z, or may contain two or more types of organic groups.

In formulas (20) to (29),

* represents a chemical bond, W ¹ represents a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -Ar ³ -, -SO ₂ -, -CO-, -O-Ar ³ -O-, -Ar ³ -O-Ar ³ -, -Ar ³ -CH ₂ -Ar ³ -, -Ar ³ -C(CH ₃ ) ₂ -Ar ³ - or -Ar ³ -SO ₂ -Ar ³ -. Ar ³ represents an arylene group having 6 to 20 carbon atoms in which a hydrogen atom may be substituted by a fluorine atom, and a specific example thereof includes a phenylene group. When a plurality of Ar ³ exists, Ar ³ may be the same or different from each other.

As the organic group of Z, formula (20'), formula (21'), formula (22'), formula (23'), formula (24'), formula (25'), formula (26') are more preferable , a divalent organic group represented by formula (27'), formula (28') and formula (29').

[In formulas (20') to (29'), W ¹ and * are as defined in formulas (20) to (29)]

In addition, the hydrogen atom on the ring in the formula (20) to the formula (29) and the formula (20') to the formula (29') may be a hydrocarbon group having 1 to 8 carbon atoms, a fluorine-substituted carbon group A hydrocarbon group having 1 to 8 atoms, an alkoxy group having 1 to 6 carbon atoms, and a fluorine-substituted alkoxy group having 1 to 6 carbon atoms are substituted.

In the polyamide-imide-based resin, when Z in the formula (b) has a structural unit represented by any one of the above formulae (20') to (29'), the polyamide-imide-based resin is: It is preferable to have, in addition to this structural unit, a structural unit derived from a carboxylic acid represented by the following formula (d1) from the viewpoint of easily improving the film formability of the varnish and easily obtaining the uniformity of the optical film obtained.

[In formula (d1), R ²⁴ independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkoxy group having 6 to 12 carbon atoms. Aryl,

R ²⁵ represents R ²⁴ or -C(=O)-*,

*indicates chemical bond]

In R ²⁴ , examples of the alkyl group having 1 to 6 carbon atoms, the alkoxy group having 1 to 6 carbon atoms, and the aryl group having 6 to 12 carbon atoms, respectively, include those in the formula (1). Examples given by R ^a . Specific examples of the structural unit (d1) include: a structural unit in which both R ²⁴ and R ²⁵ are hydrogen atoms (a structural unit derived from a dicarboxylic acid compound), where both R 24 and R ²⁴ are hydrogen atoms, and R ²⁵ represents -C A structural unit of (=O)-* (a structural unit derived from a tricarboxylic acid compound) and the like.

The dicarboxylic acid compound that provides the structural unit (b) is not particularly limited as long as it is a compound having two carbonyl groups, and examples thereof include compounds represented by formula (b').

[In formula (b'), Z represents a divalent organic group,

R ³¹ and R ³² independently represent hydroxyl, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy or chlorine atom]

In the polyamideimide-based resin of the present invention, the structural unit (c) derived from the diamine compound is represented by the formula (c).

[In formula (c), X represents a divalent organic group,

R ^c independently of each other represents a hydrogen atom or a chemical bond,

*indicates chemical bond]

Here, the structural unit (c) represented by the formula (c) is usually combined with the structural unit (a) derived from the tetracarboxylic acid compound or the structural unit (b) derived from the dicarboxylic acid compound in the polyamideimide-based resin of the present invention. ) are adjacent to each other, and usually, for example, an imide bond represented by the aforementioned formula (D) and/or an amide bond represented by the aforementioned formula (E) are formed. In the structural unit (c), R ^c independently represents a hydrogen atom or a chemical bond. When one of the chemical bonds represented by * is bonded to an adjacent structural unit derived from a tetracarboxylic acid compound, as is also clear from the formula (D), R ^c represents a chemical bond and is bonded to an adjacent structural unit derived from a tetracarboxylic acid. unit. In the structural unit (c), when one of the chemical bonds represented by * is bonded to an adjacent structural unit derived from a dicarboxylic acid compound, Rc represents a hydrogen atom, as can also be understood from the formula (E).

X in the formula (c) represents a divalent organic group, preferably a divalent organic group having 4 to 40 carbon atoms, more preferably a divalent organic group having a cyclic structure and having 4 to 40 carbon atoms group. As a cyclic structure, an alicyclic structure, an aromatic ring, and a heterocyclic structure are mentioned. In the aforementioned organic group, the hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group, and in this case, the number of carbon atoms of the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1 to 8. In one embodiment of the present invention, in the structural unit (c) contained in the polyamideimide-based resin, as X, one type of divalent organic group may be contained, or two or more types of divalent organic groups may be contained group.

The diamine compound providing the structural unit (c) is not particularly limited as long as it is a compound having two amino groups, and examples thereof include compounds represented by formula (c').

H ₂ NX-NH ₂ (c')

[In formula (c'), X represents a divalent organic group]

In the polyamideimide-based resin of the present invention, when a tetracarboxylic acid compound (for example, a compound represented by formula (8)) containing a structural unit represented by formula (1) is reacted with, for example, a diamine compound represented by formula (c') , can form the structural unit represented by formula (10).

[In formula (10), R ^a and n are as defined for R ^a and n in formula (1),

X is as defined for X in formula (c),

*indicates chemical bond]

In addition, when a dicarboxylic acid compound represented by formula (b'), for example, reacts with a diamine compound represented by formula (c'), for example, a structural unit represented by formula (11) can be formed.

[In formula (11), Z is as defined for Z in formula (b),

X is as defined for X in formula (c),

*indicates chemical bond]

In a preferred embodiment of the present invention, the polyamideimide-based resin includes the structural unit (b1) represented by the formula (2) as the structural unit (b) derived from the dicarboxylic acid compound.

[In formula (2), Z ¹ represents a divalent aromatic group which may have a substituent,

*indicates chemical bond]

The polyamideimide-based resin of the present invention usually has a plurality of structural units (b) represented by formula (b). In the present aspect, at least a part of the plurality of structural units (b) may be the structural unit (b1) represented by the formula (2). In this aspect, the polyamideimide-based resin of the present invention may have, as the structural unit (b), one type of structural unit (b1), two or more types of structural units (b1), or may have Other structural units (b) other than the structural unit (b1).

Z ¹ in formula (2) represents a divalent aromatic group which may have a substituent. A divalent aromatic group is a group in which two hydrogen atoms of a monocyclic aromatic ring, a condensed polycyclic aromatic ring, or a ring-collected aromatic ring are replaced by chemical bonds. The divalent aromatic group may contain an aromatic ring formed by only carbon atoms forming a ring (single ring, fused polycyclic ring, or a collection of rings), or may contain an aromatic ring formed by containing atoms other than carbon atoms and forming a ring Heterocycle. As an atom other than a carbon atom, a nitrogen atom, a sulfur atom, and an oxygen atom are mentioned, for example. The total number of carbon atoms and atoms other than carbon atoms forming the aromatic ring is not particularly limited, but is preferably 5-18, more preferably 5-14, still more preferably 5-13, and particularly preferably 5-12.

As a monocyclic aromatic ring, benzene, furan, pyrrole, thiophene, pyridine, imidazole, pyrazole, oxazole, thiazole, imidazoline, etc. are mentioned, for example.

Examples of the condensed polycyclic aromatic ring include naphthalene, anthracene, phenanthrene, indole, benzothiazole, benzoxazole, and benzimidazole.

Examples of ring-assembled aromatic rings include structures in which two or more monocyclic aromatic rings and/or condensed polycyclic aromatic rings are connected by a single bond. Examples thereof include monocyclic aromatic rings. A bond is a group formed by connecting two or more of the rings described above as examples of a monocyclic aromatic ring or a condensed polycyclic aromatic ring, such as biphenyl, terphenyl, tetraphenyl, Binaphthyl, 1-phenylnaphthalene, 2-phenylnaphthalene, bipyridine and the like.

From the viewpoint of easily improving the elastic modulus and total light transmittance of the optical film, the divalent aromatic group which may have a substituent is preferably a group in which two hydrogen atoms of an aromatic hydrocarbon ring are replaced by chemical bonds, More preferably, it is a group in which 2 hydrogen atoms of benzene, biphenyl, terphenyl or tetraphenyl are replaced by chemical bonds, and more preferably a group in which 2 hydrogen atoms of benzene or biphenyl are replaced by chemical bonds, especially Preferably, it is a group in which two hydrogen atoms of benzene are replaced by chemical bonds.

The divalent aromatic group represented by Z ¹ in the formula (2) may have a substituent. Examples of the substituent include (i) an alkyl group having 1 to 12 carbon atoms, (ii) an alkoxy group having 1 to 12 carbon atoms, and (iii) an alkyl group having 6 to 12 carbon atoms. At least one group selected from the group consisting of an aryl group, (iv) an aryloxy group having 6 to 12 carbon atoms, and (v) a hydroxyl group. It should be noted that the hydrogen atoms contained in the above-mentioned substituents may, independently of each other, be further replaced by a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a carboxyl group. replace. The divalent aromatic group may have a substituent selected from the above-mentioned (i) to (v), and the hydrogen atom contained in the above-mentioned substituent (i) to (v) is independently replaced by a halogen atom, a number of carbon atoms At least one substituent in the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a carboxyl group further substituted may not have a substituent. The divalent aromatic group represented by Z ¹ in the formula (2) preferably does not have a substituent from the viewpoint of easy production of an optical film having a high elastic modulus.

Examples of (i) an alkyl group having 1 to 12 carbon atoms, (ii) an alkoxy group having 1 to 12 carbon atoms, and (iii) an aryl group having 6 to 12 carbon atoms include those of the formula ( In 1) R ^a and the groups exemplified above, the preferred descriptions related to them are also applicable to the above-mentioned descriptions.

(iv) The aryloxy group having 6 to 12 carbon atoms includes a phenoxy group, a tolyloxy group, a xylyloxy group, a naphthyloxy group, a biphenyloxy group, and the like. The number of carbon atoms of the aryloxy group having 6 to 12 carbon atoms is preferably 6 or 10 or 12. The above-mentioned aryloxy group having 6 to 12 carbon atoms may be at least one hydrogen atom independently replaced by a halogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. , hydroxyl, or carboxyl substitution. As a halogen atom, the atom described above is mentioned. Here, when the aryloxy group having 6 to 12 carbon atoms is substituted with a substituent containing carbon atoms, the number of carbon atoms in the aryloxy group having 6 to 12 carbon atoms does not include those contained in the substituent. the number of carbon atoms.

In one preferred embodiment of the present invention in which the polyamide-imide-based resin of the present invention contains the structural unit (b1) represented by the formula (2) as the structural unit (b) derived from the dicarboxylic acid compound, it is easy to improve the overall performance of the optical film. From the viewpoint of light transmittance and elastic modulus, the ratio of the structural unit (b1) represented by the formula (2) is preferable when the total of the structural units (b) contained in the polyamideimide-based resin is taken as 100 mol % 70 to 100 mol %, more preferably 80 to 100 mol %, still more preferably 90 to 100 mol %, and all the structural units (b) contained in the polyamideimide-based resin may be all structural units (b1) . In addition, content of a structural unit (b) and a structural unit (b1) can be measured using ¹ H-NMR, for example, or it can also be calculated from the charging ratio of a raw material.

In a preferred embodiment of the present invention, the polyamideimide-based resin of the present invention includes a structural unit (c1) represented by formula (3) as a structural unit derived from a diamine compound.

[In formula (3), X ¹ represents a divalent aromatic group which may have a substituent,

R ^c independently of each other represents a hydrogen atom or a chemical bond,

*indicates chemical bond]

The polyamide-imide-based resin of the present invention usually has a plurality of structural units (c) represented by formula (c). In the present embodiment, at least a part of the plurality of structural units (c) may be the structural unit (c1) represented by the formula (3). In this aspect, the polyamideimide-based resin of the present invention may have, as the structural unit (c), one type of structural unit (c1), two or more types of structural units (c1), or may have Other structural units (c) other than structural unit (c1).

X ¹ in formula (3) represents a divalent aromatic group which may have a substituent. A divalent aromatic group is a group in which two hydrogen atoms of a monocyclic aromatic ring, a condensed polycyclic aromatic ring, or a ring-collected aromatic ring are replaced by chemical bonds. The divalent aromatic group may contain an aromatic ring formed by only carbon atoms forming a ring (single ring, fused polycyclic ring, or a collection of rings), or may contain an aromatic ring formed by containing atoms other than carbon atoms and forming a ring Heterocycle. As an atom other than a carbon atom, a nitrogen atom, a sulfur atom, and an oxygen atom are mentioned, for example. The total number of carbon atoms and atoms other than carbon atoms forming the aromatic ring is not particularly limited, but is preferably 5-18, more preferably 5-14, still more preferably 5-13, and particularly preferably 5-12. Examples of the monocyclic aromatic ring, the condensed polycyclic aromatic ring, and the ring-assembled aromatic ring include the examples described above regarding Z ¹ in the formula (2).

From the viewpoint of easily improving the elastic modulus and total light transmittance of the optical film, the divalent aromatic group which may have a substituent is preferably a chemical bond that replaces two hydrogen atoms of an aromatic hydrocarbon ring which may have a substituent. The group formed is more preferably a group in which 2 hydrogen atoms of benzene, biphenyl, terphenyl or tetraphenyl which can have a substituent are replaced by chemical bonds, more preferably a benzene or biphenyl which can have a substituent A group formed by replacing two hydrogen atoms of a chemical bond with a chemical bond is particularly preferably a group formed by replacing two hydrogen atoms of a biphenyl which may have a substituent with a chemical bond.

The divalent aromatic group represented by X ¹ in the formula (3) may have a substituent. Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and a halogeno group, and groups in which hydrogen atoms contained in them are replaced by halogen atoms. Examples of alkyl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, aryl groups having 6 to 12 carbon atoms, and groups in which hydrogen atoms contained in them are substituted with halogen atoms Specific examples of the group include (i) an alkyl group having 1 to 12 carbon atoms, (ii) carbon atoms as a substituent which the divalent aromatic group represented by Z ¹ in the formula (2) may have. The groups described in the alkoxy group having 1 to 12 atoms and (iii) the aryl group having 6 to 12 carbon atoms. As a halogenated group, a fluorine group, a chlorine group, a bromine group, or an iodine group can be mentioned.

As the substituent which the divalent aromatic group represented by X ¹ in the formula (3) may have, a halogen group or an alkyl group having 1 to 12 carbon atoms in which a hydrogen atom may be substituted with a halogen atom is preferable, and methyl group is more preferable. group, fluoro group, chloro group or trifluoromethyl group.

In a preferred embodiment of the present invention, X ¹ in the formula (3) is preferably represented by the formula ( 4) indicates.

[In formula (4), R ^b independently represents an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms,

The hydrogen atoms contained in R ^b independently of each other may be replaced by halogen atoms,

r independently represents an integer from 1 to 4,

*indicates chemical bond]

R ^b in formula (4) independently represents an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, and in R ^b The contained hydrogen atoms may be replaced by halogen atoms independently of each other. Examples of the alkyl group having 1 to 6 carbon atoms, the aryl group having 6 to 12 carbon atoms, and the alkoxy group having 1 to 6 carbon atoms include those represented by X ¹ in the formula (3). The substituents that the divalent aromatic group may have are the groups exemplified above. R ^b in the formula (4) is preferably an alkyl group having 1 to 6 carbon atoms substituted by a halogen atom, more preferably a fluoroalkyl group having 1 to 6 carbon atoms, and still more preferably an alkyl group having 1 to 6 carbon atoms The perfluoroalkyl group of 6 is more preferably a perfluoroalkyl group having 1 to 4 carbon atoms, particularly preferably a trifluoromethyl group or a pentafluoroethyl group, and even more preferably a trifluoromethyl group.

In formula (4), r represents an integer of 1 to 4 independently of each other, and represents preferably 1 to 3, more preferably 1 to 2, and still more preferably from the viewpoint of easily improving the total light transmittance and elastic modulus of the optical film. An integer of 1.

In a preferred embodiment of the present invention, the formula (4) is represented by the formula (4').

[In formula (4'), R ¹⁶ to R ²³ independently represent a hydrogen atom or a fluoroalkyl group having 1 to 6 carbon atoms, wherein at least one of R ¹⁶ to R ¹⁹ and R ²⁰ to R At least one of ²³ represents a fluoroalkyl group having 1 to 6 carbon atoms,

*indicates chemical bond]

From the viewpoint of easily improving the elastic modulus and total light transmittance of the optical film, in the formula (4′), it is more preferable that at least R ¹⁸ and R ²⁰ represent a fluoroalkyl group having 1 to 6 carbon atoms, and R is more preferable ¹⁸ and R ²⁰ represent a fluoroalkyl group having 1 to 6 carbon atoms, and R ¹⁶ , R ¹⁷ , R ¹⁹ , R ²¹ , R ²² and R ²³ represent a hydrogen atom. In addition, in the above-mentioned embodiment, the fluoroalkyl group having 1 to 6 carbon atoms is preferably a perfluoroalkyl group having 1 to 6 carbon atoms, more preferably a perfluoroalkyl group having 1 to 4 carbon atoms, and still more Trifluoromethyl or pentafluoroethyl is preferred, and trifluoromethyl is particularly preferred.

In a preferred embodiment of the present invention, the formula (4') is represented by the formula (4").

[In formula (4"), * represents a chemical bond]

In addition, in formula (4"), R ¹⁸ and R ²⁰ in formula (4') correspond to trifluoromethyl, and R ¹⁶ , R ¹⁷ , R ¹⁹ , R ²¹ , R ²² and R ²³ represent hydrogen Chemical formula of atoms.

In one preferred embodiment of the present invention in which the polyamideimide-based resin of the present invention contains the structural unit (c1) represented by the formula (3) as the structural unit (c) derived from the diamine compound, the total light output of the optical film is easily improved from the viewpoint of From the viewpoints of transmittance, elastic modulus, and easiness to improve the stability of the varnish, the structural unit represented by the formula (3) when the total of the structural units (c) contained in the polyamideimide-based resin is taken as 100 mol % The ratio of (c1) is preferably 50 to 98 mol %, more preferably 60 to 95 mol %, and further preferably 70 to 94 mol %. A part of the structural unit (c) contained in the polyamide-imide resin may be the structural unit (c1), or all of the structural unit (c) may be the structural unit (c1), and it is easy to improve the total light output of the optical film. From the viewpoints of transmittance, elastic modulus, and easiness to improve the stability of the varnish, it is preferable that a part of the structural unit (c) contained in the polyamideimide-based resin is the structural unit (c1). In addition, content of a structural unit (c) and a structural unit (c1) can be measured using ¹ H-NMR, for example, or it can also be calculated from the charging ratio of a raw material.

The polyamide-imide-based resin of the present invention preferably contains the one in the formula (a) from the viewpoints that the total light transmittance and elastic modulus of the optical film are easily improved, and the stability of the varnish is easily improved. Y is represented by the structural unit (a1) represented by the formula (1) as a structural unit derived from the tetracarboxylic acid compound, contains the structural unit (b1) represented by the formula (2) as a structural unit derived from the dicarboxylic acid compound, and contains the formula The structural unit (c1) represented by (3) is a structural unit derived from a diamine compound.

In a preferred embodiment of the present invention, the polyamideimide-based resin includes, as a structural unit derived from a dicarboxylic acid compound, a structural unit represented by formula (5) in Z in formula (b),

[In formula (5), Ar ¹ independently represents a divalent aromatic group which may have a substituent,

V represents -O-, diphenylmethylene, linear, branched or alicyclic divalent hydrocarbon group having 1 to 12 carbon atoms, -SO ₂ -, -S-, -CO- or -N(R ¹² )-, where the hydrogen atoms contained in the hydrocarbon group may be independently substituted by halogen atoms,

R ¹² represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms which may be substituted by a halogen atom,

m represents an integer of 1 to 3, wherein, when m is 2 or 3, there are a plurality of V which may be the same or different from each other,

*indicates chemical bond]

And/or, a structural unit represented by formula (5) in which X in formula (c) is included as a structural unit derived from a diamine compound,

And/or, a structural unit in which Y in formula (a) is represented by formula (6) is further included as a structural unit derived from a tetracarboxylic acid compound.

[In formula (6), Ar ² independently represents a trivalent aromatic group which may have a substituent,

s represents an integer from 0 to 2,

Ar ¹ , V and * are as defined for Ar ¹ , V and * in formula (5), where, when s is 2, there are a plurality of V and Ar ¹ which may be the same or different from each other]

In addition, in this specification, the structural unit represented by the formula (5) in the formula (b) that can be included as a structural unit derived from the dicarboxylic acid compound is also referred to as a "structural unit (b2)", The structural unit represented by the formula (5) in which X in the formula (c) can be included as a structural unit derived from a diamine compound is also referred to as a "structural unit (c2)", and is also referred to as a structure derived from a tetracarboxylic acid compound The structural unit represented by the formula (6) in which Y in the formula (a) may be contained is referred to as a "structural unit (a2)". The polyamide-imide-based resin of the present invention has at least the above-mentioned structural unit (a1), structural unit (b), and structural unit (c), and in a preferred embodiment, contains structural unit (b2) as structural unit (b) , contains structural unit (c2) as structural unit (c), and/or contains structural unit (a2) as structural unit (a) in addition to structural unit (a1). In this aspect, in addition to the structural unit represented by the formula (1), the polyamideimide-based resin of the present invention contains the structural unit represented by the formula (5) and/or the structural unit represented by the formula (6). . In addition, when the polyamideimide-based resin contains the structural unit (b2) as the structural unit (b), the resin may or may not contain the structural unit (b1). In addition, when the polyamideimide-based resin contains the structural unit (c2) as the structural unit (c), the resin may or may not contain the structural unit (c1).

Here, the structural unit represented by the formula (5) and the structural unit represented by the formula (6) include a linear, branched or The divalent linking group V of an alicyclic divalent hydrocarbon group, -SO ₂ -, -S-, -CO- or -N(R ¹² )-, has a highly flexible structure. When the polyamide-imide-based resin further includes the above-mentioned highly flexible structure, the intermolecular interaction of the polyamide-imide-based resin tends to be reduced. As a result, the elastic modulus of the optical film containing the polyamideimide-based resin is easily increased. In addition, the stability of the polyamideimide-based resin in the varnish state is also easily improved.

The polyamideimide-based resin of the present invention has a structural unit (b2) derived from a dicarboxylic acid compound in which Z in formula (b) is represented by formula (5), and X in formula (c) is represented by formula (5) In the case of the structural unit (c2) derived from the diamine compound and/or the structural unit (a2) derived from the tetracarboxylic acid compound represented by the formula (6) in which Y in the formula (a) is based on a polyamideimide-based resin The total amount of the structural unit (b2), the structural unit (c2) and the structural unit (a2) is preferably 1 to 25 mol %, more preferably 2 to 20 mol %, and still more preferably 3 mol ~15 mol%. When the total amount is within the above-mentioned range, the stability of the varnish is easily improved, and the processability and total light transmittance of the optical film are easily improved. In addition, in this aspect, the total amount of the structural unit (b2), the structural unit (c2), and the structural unit (a2) does not mean that the polyamideimide-based resin has all of these three types of structural units , the polyamideimide-based resin may have at least one structural unit selected from the group consisting of the structural unit (b2), the structural unit (c2), and the structural unit (a2).

In addition, when the polyamideimide-based resin of the present invention has a structural unit (b2), a structural unit (c2), and/or a structural unit (a2), with respect to the formula ( Y in a) is 1 mole of the structural unit (a1) represented by the formula (1), and the total molar amount of the structural unit (b2), the structural unit (c2) and the structural unit (a2) is preferably 0.01 to 1.0, more Preferably it is 0.02-0.50, More preferably, it is 0.05-0.20. When this total molar amount is more than the said lower limit, it becomes easy to improve the solubility in a varnish. Moreover, when this total molar amount is below the said upper limit, it becomes easy to improve the elastic modulus. In addition, also in this form, the above-mentioned total molar amount does not mean that the polyamideimide-based resin has all of these three kinds of structural units.

Ar ¹ in formula (5) and formula (6) represents a divalent aromatic group which may have a substituent. A divalent aromatic group is a group in which two hydrogen atoms of a monocyclic aromatic ring, a condensed polycyclic aromatic ring, or a ring-collected aromatic ring are replaced by chemical bonds. The divalent aromatic group may contain an aromatic ring formed by only carbon atoms forming a ring (single ring, fused polycyclic ring, or a collection of rings), or may contain an aromatic ring formed by containing atoms other than carbon atoms and forming a ring Heterocycle. As an atom other than a carbon atom, a nitrogen atom, a sulfur atom, and an oxygen atom are mentioned, for example. The total number of carbon atoms and atoms other than carbon atoms forming the aromatic ring is not particularly limited, but is preferably 5-18, more preferably 5-14, still more preferably 5-13, and particularly preferably 5-12. Examples of the monocyclic aromatic ring, the condensed polycyclic aromatic ring, and the ring-assembled aromatic ring include the examples described above regarding Z ¹ in the formula (2).

From the viewpoint of easily improving the elastic modulus and total light transmittance of the optical film, the divalent aromatic group which may have a substituent is preferably a group in which two hydrogen atoms of an aromatic hydrocarbon ring are replaced by chemical bonds, More preferably, it is a group in which two hydrogen atoms of benzene, biphenyl, terphenyl, or tetraphenyl are replaced by chemical bonds, and even more preferably, it is a group in which two hydrogen atoms of benzene or biphenyl are replaced by chemical bonds.

The divalent aromatic group represented by Ar ¹ in formula (5) and formula (6) may have a substituent. Examples of the substituent include (i) an alkyl group having 1 to 12 carbon atoms, (ii) an alkoxy group having 1 to 12 carbon atoms, and (iii) an aryl group having 6 to 12 carbon atoms. , (iv) aryloxy having 6 to 12 carbon atoms, (v) carbonyl having 1 to 12 carbon atoms, (vi) oxycarbonyl having 1 to 12 carbon atoms, or (vii) halogen Daiki. It should be noted that the hydrogen atoms contained in the above-mentioned substituents may, independently of each other, be further replaced by a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a carboxyl group. replace. The divalent aromatic group may have at least one of the substituents (i) to (vii) above, and/or the hydrogen atoms contained in the substituents (i) to (vii), independently of each other, may be further replaced by halogen atoms. , A C1-C4 alkyl group, a C1-C4 alkoxy group, a hydroxyl group, or a carboxyl group substituted group may not have a substituent. The divalent aromatic group represented by Ar ¹ in formula (5) and formula (6) preferably does not have a substituent from the viewpoint of easy production of an optical film having a high elastic modulus.

(i) an alkyl group having 1 to 12 carbon atoms, (ii) an alkoxy group having 1 to 12 carbon atoms, (iii) an aryl group having 6 to 12 carbon atoms, and (iv) a carbon number The aryloxy group of 6 to 12 includes the groups exemplified above about the substituent which the divalent aromatic group represented by Z ¹ in the formula (2) may have.

(v) The carbonyl group having 1 to 12 carbon atoms is a group represented by *-CO-R ^d or *-R ^e -CO-R ^d . Examples of R ^d include those described for (i) an alkyl group having 1 to 12 carbon atoms, and examples of ^Re include those described for (i) an alkyl group having 1 to 12 carbon atoms. A divalent alkylene group having 1 to 12 carbon atoms in which at least one hydrogen atom in the group is replaced by a chemical bond. The above-mentioned carbonyl group having 1 to 12 carbon atoms may be at least one hydrogen atom independently replaced by a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a group obtained by substitution of a carboxyl group. As a halogen atom, the atom described above is mentioned. Here, when the carbonyl group having 1 to 12 carbon atoms is substituted with a substituent containing carbon atoms, the number of carbon atoms contained in the substituent is not included in the number of carbon atoms of the carbonyl group having 1 to 12 carbon atoms.

(vi) The oxycarbonyl group having 1 to 12 carbon atoms is *-CO-OR ^d , *-R ^e -CO-OR ^d , *-O-CO-R ^d , or -R ^e -O-CO- The group represented by R ^d . Examples of R ^d include those described for (i) an alkyl group having 1 to 12 carbon atoms, and examples of ^Re include those described for (i) an alkyl group having 1 to 12 carbon atoms. A divalent alkylene group having 1 to 12 carbon atoms in which at least one hydrogen atom in the group is replaced by a chemical bond. The above-mentioned oxycarbonyl group having 1 to 12 carbon atoms may be at least one hydrogen atom independently replaced by a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, A group obtained by substitution of a hydroxyl group or a carboxyl group. As a halogen atom, the atom described above is mentioned. Here, when the oxycarbonyl group having 1 to 12 carbon atoms is substituted with a substituent containing carbon atoms, the number of carbon atoms in the oxycarbonyl group having 1 to 12 carbon atoms does not include the carbon contained in the substituent. the number of atoms.

As (vii) the halogenated group, a fluorine group, a chlorine group, a bromine group or an iodine group can be mentioned.

Ar ² in formula (6) represents a trivalent aromatic group which may have a substituent. A trivalent aromatic group is a group in which three hydrogen atoms in a monocyclic aromatic ring, a condensed polycyclic aromatic ring, or a ring-collected aromatic ring are replaced by chemical bonds. The trivalent aromatic group may contain an aromatic ring formed by only carbon atoms forming a ring (single ring, condensed polycyclic ring, or a collection of rings), or may contain an aromatic ring formed by containing atoms other than carbon atoms and forming a ring Heterocycle. As an atom other than a carbon atom, a nitrogen atom, a sulfur atom, and an oxygen atom are mentioned, for example. The total number of carbon atoms and atoms other than carbon atoms forming the aromatic ring is not particularly limited, but is preferably 5-18, more preferably 5-14, still more preferably 5-13, and particularly preferably 5-12. Examples of the monocyclic aromatic ring, the condensed polycyclic aromatic ring, or the ring-assembled aromatic ring in the trivalent aromatic group include the examples described above for Ar ¹ . Examples of the substituent which the trivalent aromatic group may have include the substituents described above for Ar ¹ , and the preferred descriptions for Ar ¹ are also applicable to Ar ² .

From the viewpoint of easily improving the elastic modulus and total light transmittance of the optical film, the trivalent aromatic group which may have a substituent is preferably a group in which three hydrogen atoms of an aromatic hydrocarbon ring are replaced by chemical bonds, More preferably, it is a group in which three hydrogen atoms of benzene, biphenyl, terphenyl, or tetraphenyl are replaced by chemical bonds, and even more preferably, it is a group in which three hydrogen atoms of benzene or biphenyl are replaced by chemical bonds.

When m in the formula (5) is 1 or more, and/or when s in the formula (6) is 2, the Ar ¹ that exists in plural may be the same or different from each other. In addition, Ar ² which exists in plural in Formula (6) may be the same or different from each other.

m in formula (5) represents an integer of 1 to 3, and is preferably 1 or 2, and more preferably 1, from the viewpoint of improving the elastic modulus and securing solubility in a varnish. * in formula (5) represents a chemical bond.

s in Formula (6) represents an integer of 0 to 2, and is preferably 0 or 1, and more preferably 0, from the viewpoint of securing solubility in a varnish and securing high transmittance. * in formula (6) represents a chemical bond.

V in the formulas (5) and (6) represents -O-, a diphenylmethylene group, a linear, branched or alicyclic divalent hydrocarbon group having 1 to 12 carbon atoms, -SO _2- , -S-, -CO- or -N(R ¹² )-, where the hydrogen atoms contained in the hydrocarbon group may be independently substituted by halogen atoms, and R ¹² represents hydrogen atoms or may be substituted by halogen atoms An alkyl group having 1 to 12 carbon atoms. Examples of the linear, branched, or alicyclic alkyl group having 1 to 12 carbon atoms include those described in relation to the alkyl group having 1 to 12 carbon atoms in R ^a in formula (1). group.

Regarding V in the formula (5) and the formula (6), as the linear, branched or alicyclic divalent hydrocarbon group having 1 to 12 carbon atoms, there may be mentioned one having 1 to 12 carbon atoms. A group obtained by replacing at least one hydrogen atom of a linear, branched or alicyclic alkyl group with a chemical bond. In addition, as said C1-C12 linear, branched or alicyclic alkyl group, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl, sec-butyl, tert-butyl, n-pentyl, 2-methylbutyl, 3-methylbutyl, 2-ethylpropyl, n-hexyl, n-heptyl, n-octyl, tert-octyl base, n-nonyl, n-decyl, cyclopentyl, cyclohexyl, etc. The divalent hydrocarbon group having 1 to 12 carbon atoms may be a linear alkylene group, a branched alkylene group, or an alicyclic alkylene group including an alicyclic hydrocarbon structure. The number of carbon atoms of the divalent hydrocarbon group having 1 to 12 carbon atoms is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 to 3. The above-mentioned divalent hydrocarbon group having 1 to 12 carbon atoms may be a group in which at least one hydrogen atom is independently substituted by a halogen atom. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned.

In formula (5) and formula (6), when there are a plurality of Ar ¹ , Ar ² and/or V, they may be the same or different from each other, but are preferred from the viewpoint of easy synthesis of polyamideimide-based resins. What is true is that there are multiple Ar ^1s that are identical to each other, that there are multiple Ar ² that are the same as each other, and/or that there are multiple V that are the same.

In a preferred embodiment of the present invention, the formula (5) and the formula (6) are preferably represented by the formula (7).

[In formula (7), R ¹ independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms,

The hydrogen atoms contained in R ¹ independently of each other may be substituted by halogen atoms,

R ^* means ^R1 or chemical bond,

* denotes chemical bond,

V represents -O-, diphenylmethylene, linear, branched or alicyclic divalent hydrocarbon group having 1 to 12 carbon atoms, -SO ₂ -, -S-, -CO- or -N(R ¹² )-, where the hydrogen atoms contained in the hydrocarbon group may be independently substituted by halogen atoms,

R ¹² represents a hydrogen atom, or an alkyl group having 1 to 12 carbon atoms which may be substituted by a halogen atom]

In addition, when Formula (5) is represented by Formula (7), since the chemical bond in Formula (7) becomes two, R ^* represents R< ¹ >. In addition, when Formula (6) is represented by Formula (7), since there are four chemical bonds in Formula (7), R ^* represents a chemical bond. In addition, about R ¹ in formula (7), the description about the substituent which Ar ¹ in formula (5) and Ar ² in formula (6) may have is applied similarly, and the description about preferable is also applicable. In addition, about V in Formula (7), the description about V in Formula (5) and Formula (6) also applies similarly.

In a preferred embodiment of the present invention, when the polyamideimide-based resin contains a structural unit (c2) represented by the formula (5) or the formula (7) in which X in the formula (c) is a structural unit derived from a diamine compound , and/or, when Y in formula (a) is further included as a structural unit (a2) represented by formula (6) or formula (7) as a structural unit derived from a tetracarboxylic acid compound, from the elastic modulus of the optical film, From the viewpoint of total light transmittance, surface hardness, and bending resistance, and from the viewpoint of stability of the varnish, V in the formulae (5), (6) and (7) preferably represents -O-, diphenylene A methyl group, a linear, branched or alicyclic divalent hydrocarbon group having 1 to 12 carbon atoms, or a hydrogen atom contained in a divalent hydrocarbon group having 1 to 12 carbon atoms is substituted with a halogen atom. More preferably, it represents a divalent hydrocarbon group having 1 to 12 carbon atoms, or a group in which hydrogen atoms contained in a divalent hydrocarbon group having 1 to 12 carbon atoms are substituted with halogen atoms.

In this embodiment, V in formula (5), formula (6) and formula (7) is more preferably at least 1 of a linear, branched or alicyclic alkylene group having 1 to 12 carbon atoms. A group in which one hydrogen atom is substituted by a halogen atom (preferably a fluorine atom) (preferably a fluoroalkylene group having 1 to 12 carbon atoms), more preferably a straight chain having 1 to 12 carbon atoms, A group in which all hydrogen atoms in a branched or alicyclic alkylene group are substituted with halogen atoms (preferably fluorine atoms) (preferably a perfluoroalkylene group having 1 to 12 carbon atoms, particularly preferably a bis- trifluoromethylmethylene).

In this aspect, the formula (7) is preferably represented by the formula (7') or the formula (7").

[In formula (7'), R ^* represents a hydrogen atom or a chemical bond,

*indicates chemical bond]

[In formula (7"), * represents a chemical bond]

When the polyamideimide-based resin further contains a structural unit (a2) represented by the formula (6) in the formula (a) as a structural unit derived from the tetracarboxylic acid compound, and when the polyamideimide resin contains X in the formula (c) by the formula When the structural unit (c2) represented by (5) is the structural unit (c) derived from the diamine compound, the formula (5) is preferably represented by the formula (7), and the formula (7) is more preferably represented by the formula (7′). In addition, when the polyamideimide-based resin contains the structural unit (b2) represented by the formula (5) in which Z in the formula (b) is a structural unit derived from the dicarboxylic acid compound, it is preferable that the formula (5) is represented by the formula (7) represented, more preferably the formula (7) is represented by the formula (7").

In a preferred embodiment of the present invention, the polyamideimide-based resin not only has the above-mentioned structural unit (a1), structural unit (b), and structural unit (c), but also has at least Y in formula (a) represented by the formula Structural unit (a2) derived from the tetracarboxylic acid compound represented by (6). In this case, the amount of the structural unit (a2) is preferably 1 to 25 mol %, more preferably 2 to 20 mol %, and even more preferably 3 mol % based on all structural units contained in the polyamideimide-based resin. ~15 mol%. When the amount of the structural unit (a2) is within the above-mentioned range, the stability of the varnish is easily improved, and the workability and total light transmittance of the optical film are easily improved.

In another preferred aspect of the present invention, the polyamideimide-based resin has not only the above-mentioned structural unit (a1) and structural unit (b), but also at least a structure in which X in formula (c) is represented by formula (5). The unit (c2) is the structural unit (c) derived from the diamine compound. In addition, in this form, among the some structural unit (c) which exists in the polyamideimide-type resin, at least a part of structural units should just be a structural unit (c2). When the polyamideimide-based resin has at least the above-mentioned structural unit (a1), structural unit (b), and structural unit (c2), the structural unit ( The amount of c2) is preferably 1 to 25 mol %, more preferably 2 to 20 mol %, further preferably 3 to 15 mol %. When the amount of the structural unit (c2) is within the above-mentioned range, the stability of the varnish is easily improved, and the workability and total light transmittance of the optical film are easily improved.

In a preferred embodiment of the present invention, the polyamideimide-based resin includes, as a structural unit derived from a dicarboxylic acid compound, a structural unit (b2) in which Z in the formula (b) is represented by the formula (5) or the formula (7). , V in the formulas (5) and (7) preferably represents -O- , a diphenylmethylene group, a linear, branched or alicyclic divalent hydrocarbon group having 1 to 12 carbon atoms, or a hydrogen atom contained in a divalent hydrocarbon group having 1 to 12 carbon atoms is The group obtained by substitution with a halogen atom more preferably represents -O-.

In this aspect, the formula (5) is preferably represented by the formula (9).

[In formula (9), R ⁴ to R ¹¹ independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkoxy group having 6 to 12 carbon atoms. aryl,

The hydrogen atoms contained in R ⁴ to R ¹¹ may be independently substituted by halogen atoms,

m is an integer from 1 to 4,

*indicates chemical bond]

R ⁴ to R ¹¹ in the formula (9) independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkyl group having 6 to 12 carbon atoms. In the aryl group, the hydrogen atoms contained in R ⁴ to R ¹¹ may be independently substituted with halogen atoms. Examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, and 2-methyl. Butyl, 3-methylbutyl, 2-ethylpropyl, n-hexyl, etc. Examples of the alkoxy group having 1 to 6 carbon atoms include methoxy, ethoxy, propyloxy, isopropyloxy, butoxy, isobutoxy, tert-butoxy, Amyloxy, hexyloxy, cyclohexyloxy and the like. As a C6-C12 aryl group, a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a biphenyl group, etc. are mentioned, for example. From the viewpoints of surface hardness and flexibility of the optical film, R ⁴ to R ¹¹ each independently preferably represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and more preferably represent a hydrogen atom or a carbon number of 1 to 3 The alkyl group further preferably represents a hydrogen atom. Here, hydrogen atoms included in R ⁴ to R ¹¹ may be independently substituted with halogen atoms. As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned.

m in formula (9) is an integer of 1 to 4, and when m is within the above range, the bending resistance and elastic modulus of the optical film are likely to be favorable. Moreover, it is preferable that m in Formula (9) is an integer in the range of 1-3, More preferably, it is 1-2, More preferably, it is 1. When m is in the said range, it becomes easy to improve the bending resistance and elastic modulus of an optical film. When the polyamideimide-based resin of the present invention has a structural unit in which Z in the formula (b) is represented by the formula (9) as the structural unit (b) derived from the dicarboxylic acid compound, the polyamideimide-based resin may have Z in formula (b) is one kind or two or more kinds of structural units represented by formula (9).

In this aspect, the formula (9) is preferably represented by the formula (7").

In this case, the surface hardness and bending resistance of the optical film are easily improved, and the yellowness is easily lowered.

The polyamideimide resin of the present invention contains a structural unit (b2) in which Z in formula (b) is represented by formula (5), formula (7), formula (9) or formula (7") as a dicarboxylic acid derived from In the case of the structural unit (b) of the compound, the ratio of the structural unit (b2) is preferably 1 mol % or more, and more preferably 100 mol % of the total structural unit contained in the polyamideimide resin. 2 mol% or more, more preferably 3 mol% or more, particularly preferably 4 mol% or more, preferably 45 mol% or less, more preferably 35 mol% or less, still more preferably 25 mol% or less, particularly preferably 15 mol% Below. When the ratio of the structural unit (b2) is more than the above-mentioned lower limit, it is easy to improve the surface hardness and bending resistance of the optical film. In addition, when the ratio is below the above-mentioned upper limit, it is easy to suppress the viscosity of the resin-containing varnish from rising, and it is easy to The processability of the film is improved. In addition, the content of these structural units can be measured using ¹ H-NMR, for example, or can be calculated from the charge ratio of the raw materials.

In a preferred embodiment of the present invention, the polyamideimide resin of the present invention contains Z in formula (b) represented by formula (5), formula (7), formula (9) or formula (7") When the structural unit (b2) is the structural unit (b) derived from the dicarboxylic acid compound, the structural unit (b) is preferably 5 mol % or more, more preferably 8 mol % or more, further preferably 10 mol % or more, and particularly preferably 12 mol % or more. Molar % or more is the structural unit (b2). When the amount of the structural unit (b2) is in the above-mentioned range, the surface hardness of the optical film is easily improved, and the bending resistance and elastic modulus are easily improved. In addition, the polyamide of the present invention is preferred Among the structural units (b) derived from the dicarboxylic acid compound contained in the imide-based resin, preferably 90 mol% or less, more preferably 70 mol% or less, still more preferably 50 mol% or less, and particularly preferably 30 mol% or less are structural units (b2).When the amount of the structural unit (b2) is in the above-mentioned range, it is easy to suppress the viscosity increase of the varnish containing the resin, and it is easy to improve the processability of the film. The polyamideimide resin of the present invention contains the structural unit of the above-mentioned amount. When (b2) is a structural unit (b) derived from a dicarboxylic acid compound, it is preferable to have the above-mentioned structural unit (b1) as another structural unit (b).

The polyamideimide-based resin of the present invention includes not only the structural unit (a1) represented by the formula (1) in which Y in the formula (a) is represented, but also at least the structural unit (b) and the formula (c) represented by the formula (b). ) represents the structural unit (c). Here, the polyamideimide-based resin of the present invention is preferably not only Structural unit (a1) in which Y in formula (a) is represented by formula (1), and also includes:

(i) a structural unit (c2) in which X in the formula (c) is represented by the formula (5) as the structural unit (c) derived from the diamine compound,

(ii) a structural unit (a2) in which Y in the formula (a) is represented by the formula (6) as the structural unit (a) derived from the tetracarboxylic acid compound,

(iii) a structural unit (b2) in which Z in the formula (b) is represented by the formula (5) as the structural unit (b) derived from the dicarboxylic acid compound,

(iv) a structural unit (c1) in which X in the formula (c) is represented by the formula (3) as the structural unit (c) derived from the diamine compound,

and/or

(v) Structural unit (b1) in which Z in formula (b) is represented by formula (2) as structural unit (b) derived from a dicarboxylic acid compound.

From the viewpoints that the varnish stability of the polyamideimide-based resin is easily improved, and the total light transmittance, elastic modulus, surface hardness, and bending resistance of the resulting optical film are easily improved, the polyamideimide of the present invention The amine-based resin preferably has the above-mentioned (iv) and (v) in addition to the structural unit (a1) in which Y in the formula (a) is represented by the formula (1), and/or further has At least one of the above (i) to (iii); more preferably, in addition to the structural unit (a1) in which Y in the formula (a) is represented by the formula (1), the above (iv) and ( v) and at least one of (i) to (iii) above. Moreover, when the polyamideimide-type resin of this invention has at least 1 type of said (i)-(iii), it is preferable to have said (i) at least.

In the polyamide-imide-based resin of the present invention, the structural unit (a), the structural unit (b), and the structural unit (c) may form an imide bond represented by the above-mentioned formula (D) and the above-mentioned formula ( The structure of the amide bond represented by E), in addition to the structures represented by (D) and (E), for example, the structural unit (a) and the structural unit (c) may be included in the structure represented by the formula (30). , the structural unit (d) and the structural unit (c) different from the structural units (a) to (c) may form the structural unit represented by the formula (31) and be included.

In formula (30), Y ¹ is a tetravalent organic group, preferably a tetravalent organic group in which a hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. Y ¹ may be, for example, a structural unit represented by formula (1). In one embodiment of the present invention, the polyamideimide-based resin may contain multiple types of Y ¹ , and multiple types of Y ¹ may be the same or different from each other.

In formula (31), Y ² is a trivalent organic group, preferably a trivalent organic group in which a hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. In one embodiment of the present invention, the polyamideimide-based resin may contain multiple types of Y ² , and multiple types of Y ² may be the same or different from each other.

In formula (30) and formula (31), X ² and X ³ are independently a divalent organic group, preferably an organic group in which a hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. As X ² and X ³ , the group described as X in the formula (c) and the group described as X′ in the formula (2) may, for example, be mentioned.

In one embodiment of the present invention, the polyamideimide-based resin includes a structural unit represented by formula (D) composed of a structural unit (a) derived from a tetracarboxylic acid compound and a structural unit (c) derived from a diamine compound, A structural unit represented by the formula (E) composed of a structural unit (b) derived from a dicarboxylic acid compound and a structural unit (c) derived from a diamine compound, and a structural unit represented by the formula (30) in some cases, and/or A structural unit represented by formula (31). From the viewpoint of easily improving the elastic modulus, total light transmittance, optical properties, and surface hardness of the optical film, among the above-mentioned polyamideimide-based resins, those based on formula (D) and formula (E), and depending on the case The total of the structural units represented by the formula (30) and the formula (31), the structural units represented by the formula (D) and the formula (E) is preferably 80 mol % or more, more preferably 90 mol % or more, and still more preferably 95 mol % above. In addition, in the polyamideimide-based resin, based on the total of the structural units represented by the formula (D) and the formula (E), and the formula (30) and/or the formula (31) in some cases, the formula (D) ) and the structural units represented by the formula (E) are usually 100% or less. In addition, the said ratio can be measured using ¹ H-NMR, for example, or it can also be calculated from the charging ratio of a raw material.

In one embodiment of the present invention, the content of the polyamideimide-based resin in the optical film is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 50 parts by mass relative to 100 parts by mass of the optical film. Parts by mass or more, preferably 99.5 parts by mass or less, and more preferably 95 parts by mass or less. When the content of the polyamideimide-based resin is within the above range, the optical properties, elastic modulus, and total light transmittance of the optical film are easily improved.

The elastic modulus of the optical film of the present invention is preferably 5.2 GPa or more, more preferably 5.5 GPa or more, still more preferably 5.8 GPa or more, and still more preferably 6.0 GPa or more, from the viewpoint of easily preventing wrinkles, damage, etc. of the optical film. , especially preferably 6.2GPa or more, especially more preferably 6.4GPa or more, and usually 100GPa or less. It should be noted that the elastic modulus can be measured using a tensile tester, for example, the distance between the chucks is 50 mm and the tensile speed is 10 mm/min. For example, the method described in the examples can be used. to measure.

The total light transmittance of the optical film of the present invention is preferably 80% or more, more preferably 85% or more, still more preferably 88% or more, still more preferably 89% or more, particularly preferably 90% or more, usually 100% the following. When the total light transmittance is equal to or more than the above-mentioned lower limit, when the optical film is incorporated in a display device as a front panel in particular, it is easy to improve the visibility. The optical film of the present invention generally exhibits high total light transmittance, and therefore can suppress the luminous intensity of a display element or the like, which is required to obtain a constant brightness, compared to the case of using a film with a low transmittance, for example. Therefore, power consumption can be reduced. For example, when the optical film of the present invention is incorporated into a display device, a bright display tends to be obtained even if the light quantity of the backlight is reduced, and it can contribute to energy saving. In addition, the total light transmittance can be measured using a haze computer according to JIS K 7361-1:1997, for example. The total light transmittance may be the total light transmittance within the range of the thickness of the optical film to be described later. In addition, in this specification, the excellent optical characteristic of an optical film means that the total light transmittance is high.

The haze of the optical film of the present invention is preferably 5% or less, more preferably 4% or less, still more preferably 3% or less, still more preferably 2.5% or less, still more preferably 2% or less, and particularly preferably 1% or less , especially more preferably 0.5% or less, usually 0.01% or more. When the haze of an optical film is below the said upper limit, it becomes easy to improve visibility when an optical film is incorporated in a display apparatus especially as a front panel. In addition, haze can be measured using a haze computer according to JIS K7136:2000.

The yellowness of the optical film of the present invention (hereinafter, abbreviated as YI value in some cases) is preferably 3.5 or less, more preferably 3.0 or less, still more preferably 2.5 or less, usually -5 or more, preferably -2 or more. When the yellowness of an optical film is below the said upper limit, transparency becomes favorable, and when it applies to the front panel of a display apparatus, it can contribute to high visibility. It should be noted that, for the YI value, the transmittance with respect to light of 300 to 800 nm can be measured using an ultraviolet-visible-near-infrared spectrophotometer, and the tristimulus values (X, Y, Z) can be obtained, based on It is calculated by the formula of YI=100×(1.2769X-1.0592Z)/Y.

The thickness of the optical film of the present invention is preferably 10 μm or more, more preferably 20 μm or more, further preferably 25 μm or more, particularly preferably 30 μm or more, preferably 200 μm or less, more preferably 100 μm or less, still more preferably 80 μm or less, particularly preferably It is 60 micrometers or less, and the combination of these upper and lower limits may be sufficient. When the thickness of an optical film is in the said range, it becomes easy to further improve the elastic modulus of an optical film. In addition, the thickness of an optical film can be measured using a micrometer, for example, it can be measured by the method described in an Example.

The pencil hardness of at least one surface of the optical film of this invention becomes like this. Preferably it is HB or more, More preferably, it is F or more. When the pencil hardness of at least one surface of an optical film is the said hardness or more, it becomes easy to prevent the damage etc. in the said surface of an optical film. In addition, pencil hardness can be measured according to JISK5600-5-4:1999.

The imidization rate of the polyamideimide-based resin is preferably 90% or more, more preferably 93% or more, still more preferably 96% or more, and usually 100% or less. From the viewpoint of easily improving the optical properties of the optical film, the imidization ratio is preferably equal to or more than the above-mentioned lower limit. The imidization ratio represents the imide bond in the polyamide-imide-based resin with respect to the value twice the molar amount of the structural unit derived from the tetracarboxylic acid compound in the polyamide-imide-based resin molar ratio. In addition, when the polyamide-imide-based resin contains a tricarboxylic acid compound, it represents the value twice the molar amount of the structural unit derived from the tetracarboxylic acid compound in the polyamide-imide-based resin and the value derived from the tricarboxylic acid compound. The ratio of the molar amount of the imide bond in the polyamideimide-based resin in terms of the total molar amount of the structural units of the carboxylic acid compound. In addition, the imidization rate can be calculated|required by IR method, NMR method, etc..

The content of the halogen atom in the polyamideimide-based resin is preferably 1 to 40% by mass, more preferably 5 to 40% by mass, and even more preferably 5% by mass based on the mass of the polyamideimide-based resin. ~30 mass %. When content of a halogen atom is more than the said minimum, it becomes easy to further improve the elastic modulus, surface hardness, transparency, and visibility of an optical film. The synthesis|combination of resin becomes easy that content of a halogen atom is below the said upper limit.

<Production method of resin>

The polyamide-imide-based resin of the present invention can be produced using a tetracarboxylic acid compound, a dicarboxylic acid compound, and a diamine compound as main raw materials. Here, the polyamideimide-based resin of the present invention contains the structural unit (a1) in which Y in the formula (a) is represented by the formula (1) as a structural unit derived from the tetracarboxylic acid compound, and therefore, as a raw material, at least A tetracarboxylic acid compound containing the structure represented by formula (1).

As a tetracarboxylic acid compound which can be used for manufacture of resin, the tetracarboxylic compound which provides the structural unit (a1) in which Y in formula (a) is represented by formula (1), for example, aromatic tetracarboxylic acid is mentioned. Aromatic tetracarboxylic acid compounds such as dianhydrides. The tetracarboxylic acid compound may be used alone or in combination of two or more. A tetracarboxylic-acid compound analog, such as an acid chloride compound, may be sufficient as a tetracarboxylic-acid compound other than a dianhydride. For example, the compound represented by the above-mentioned formula (8) is mentioned.

As a tetracarboxylic acid compound which can be used for the manufacture of resin, the compound (tetracarboxylic dianhydride) represented by the above-mentioned formula (8), for example, 3,3',4,4'-biphenyltetracarboxylic dianhydride can be mentioned (BPDA).

Moreover, 4,4'-oxydiphthalic dianhydride (4,4'-oxydiphthalic dianhydride), 2,2',3,3' is mentioned as another tetracarboxylic acid compound which can be used for manufacture of resin - Benzophenone tetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, 2,2- Bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenoxybenzene base) propane dianhydride, 4,4'-(hexafluoroisopropylidene) diphthalic dianhydride (4,4'-(hexafluoroisopropylidene) diphthalic dianhydride, sometimes described as 6FDA), 1,2-bis(2, 3-Dicarboxyphenyl)ethanedianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethanedianhydride, 1,2-bis(3,4-dicarboxyphenyl)ethanedi Anhydride, 1,1-bis(3,4-dicarboxyphenyl)ethanedianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methanedi anhydride, 4,4'-(terephenylenedioxy)diphthalic anhydride, 4,4'-(isophenylenedioxy)diphthalic anhydride. Moreover, as monocyclic aromatic tetracarboxylic dianhydride, for example, 1,2,4,5-mellitic dianhydride (pyromellitic dianhydride (PMDA)) is mentioned, as condensed polycyclic dianhydride As the aromatic tetracarboxylic dianhydride, for example, 2,3,6,7-naphthalenetetracarboxylic dianhydride can be mentioned.

Among these, as the tetracarboxylic acid compound, 4,4'-oxybisphthalic anhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2', 3,3'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 1,2,4,5-mellitic dianhydride (PMDA) , 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxybenzene base) propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenoxyphenyl)propane dianhydride, 1,2 -Bis(2,3-dicarboxyphenyl)ethanedianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethanedianhydride, 1,2-bis(3,4-dicarboxybenzene base) ethanedianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethanedianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxylate) Phenyl)methane dianhydride, 4,4'-(terephenylenedioxy)bisphthalic anhydride, and 4,4'-(isophenylenedioxy)bisphthalic anhydride, and more preferable examples include 4,4'-oxybisphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 2,2',3,3'-biphenyltetracarboxylic dianhydride, Bis(3,4-dicarboxyphenyl)methane dianhydride, 4,4'-(terephenylenedioxy)bisphthalic anhydride and 1,2,4,5-mellitic dianhydride (PMDA) . These can be used individually or in combination of 2 or more types.

From the viewpoints of the elastic modulus, total light transmittance, surface hardness, and bending resistance of the optical film, as the tetracarboxylic acid compound that can be used in the production of the resin, a 3,3',4,4'-linked compound is preferably used. pyromellitic dianhydride (BPDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), and 4,4'-(hexafluoroisopropylidene)diphthalic acid are also preferably used Anhydride (6FDA).

As dicarboxylic acid compounds that can be used in the production of polyamideimide-based resins, aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and their analogous acid chloride compounds, acid anhydrides, etc. may be mentioned, and these dicarboxylic acids may be used in combination. Two or more kinds of carboxylic acid compounds. As the dicarboxylic acid compound, terephthalic acid, isophthalic acid, 4,4'-oxybisbenzoic acid, or acid chloride compounds thereof can be preferably used. In addition to terephthalic acid, 4,4'-oxydibenzoic acid or their acid chloride compounds, other dicarboxylic acid compounds may be used. Specific examples of other dicarboxylic acid compounds include isophthalic acid; naphthalenedicarboxylic acid; 4,4'-biphenyl dicarboxylic acid; ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ - or phenylene, a dicarboxylic acid compound of a chain hydrocarbon having 8 or less carbon atoms, and two benzoic acids Linked compounds and their acid chlorides. As a specific example, 4,4'-oxybis(benzoyl chloride) (4,4'-oxybis(benzoylchloride)) and terephthaloyl chloride are preferable, and 4,4'-oxybis(benzoyl chloride) is more preferable. acid chloride) and terephthaloyl chloride in combination.

As a diamine compound which can be used for manufacture of the polyamideimide-type resin of this invention, an aromatic diamine is mentioned, for example. In addition, in this embodiment, "aromatic diamine" means the diamine in which an amino group couple|bonded directly to an aromatic ring, and a part of the structure may contain an aliphatic group or another substituent. The aromatic ring may be a single ring or a condensed ring, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, and a fluorene ring, and preferably a benzene ring, but are not limited to these.

Examples of the aromatic diamine include p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, m-xylylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene, 2,5-diaminonaphthalene, Aromatic diamines having one aromatic ring such as 6-diaminonaphthalene, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl base ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone , 3,3'-diaminodiphenylsulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, bis[4-(4- Aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2, 2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diamino Biphenyl (sometimes described as TFMB), 4,4'-bis(4-aminophenoxy)biphenyl, 9,9-bis(4-aminophenyl)fluorene, 9,9-bis(4-amino- 3-methylphenyl) fluorene, 9,9-bis(4-amino-3-chlorophenyl)fluorene, 9,9-bis(4-amino-3-fluorophenyl)fluorene, etc. have two or more aromatic groups Cyclic aromatic diamines. These can be used individually or in combination of 2 or more types.

The aromatic diamine is preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl Phenyl ether, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 1,4-bis(4-aminophenoxy)benzene, bis[4-(4- Aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2, 2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diamino Biphenyl (TFMB), 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-(hexafluoropropylidene)diphenylamine (6FDAM), more preferably 4,4'-diamino Diphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 1,4-bis(4-amino phenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis Methylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 4,4'-bis(4-aminophenoxy)biphenyl, 4, 4'-(hexafluoropropylidene)diphenylamine (6FDAM). These can be used individually or in combination of 2 or more types.

As a diamine compound which can be used for manufacture of the polyamideimide-type resin of this invention, an aliphatic diamine can be used in addition to an aromatic diamine. In addition, the "aliphatic diamine" means the diamine in which an amino group couple|bonded directly with an aliphatic group, and an aromatic ring and another substituent may be contained in a part of the structure. Examples of aliphatic diamines include acyclic aliphatic diamines such as 1,6-hexanediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl) ) Cycloaliphatic diamines such as cyclohexane, norbornanediamine, and 4,4'-diaminodicyclohexylmethane, etc.

Among the above-mentioned diamine compounds, it is preferable to use an aromatic compound selected from the group consisting of aromatic compounds having a biphenyl structure from the viewpoint of easily improving the surface hardness, total light transmittance, elastic modulus, flexibility, bending resistance, and low colorability of the optical film. 1 or more kinds in the group which consists of group diamines. More preferably, it is selected from 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)benzidine, 4,4'-bis(4-aminophenoxy)biphenyl and 4,4'-bis(4-aminophenoxy)biphenyl. 1 or more selected from the group consisting of 4'-diaminodiphenyl ether and 4,4'-(hexafluoropropylidene)diphenylamine, more preferably 2,2'-bis(trifluoromethyl)-4, 4'-diaminobiphenyl (TFMB) and/or 4,4'-(hexafluoropropylidene)diphenylamine (6FDAM).

In addition, the above-mentioned polyamide-imide-based resin may be a range that does not impair various physical properties of the optical laminate, in addition to the above-mentioned tetracarboxylic acid compound, tetracarboxylic acid, tricarboxylic acid, and their anhydrides may be made products obtained by reacting with derivatives.

As another tetracarboxylic acid, the water adduct of the anhydride of the said tetracarboxylic acid compound is mentioned.

As a tricarboxylic acid compound, an aromatic tricarboxylic acid, an aliphatic tricarboxylic acid, these similar acid chloride compounds, acid anhydrides, etc. are mentioned, You may use it in combination of 2 or more types. Specific examples include 1,3,5-benzenetricarboxylic acid or its acid chloride compound, anhydride of 1,2,4-benzenetricarboxylic acid; 2,3,6-naphthalene-2,3-anhydride; A single bond, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ - or phenylene, connects phthalic anhydride and benzoic acid compound of.

In the manufacture of resin, the usage-amount of a diamine compound, a tetracarboxylic acid compound, and/or a dicarboxylic acid compound can be suitably selected according to the ratio of each structural unit of a desired polyamideimide-type resin.

The method for producing the polyamide-imide-based resin of the present invention is not particularly limited as long as the above-mentioned polyamide-imide-based resin can be obtained. From the viewpoints of easily improving the elastic modulus and total light transmittance of the optical film, From the viewpoint of easily improving the stability of the polyamideimide-based resin in the varnish state, it is preferable to use a production method in which the dicarboxylic acid compound is added in portions and the diamine compound, the tetracarboxylic acid compound, and the dicarboxylic acid compound are reacted. , to produce a polyamide-imide-based resin; more preferably, a polyamide-imide-based resin is produced by a method including a step of reacting a diamine compound and a tetracarboxylic acid compound to generate an intermediate (A) (I) and the step (II) of reacting the intermediate (A) with the dicarboxylic acid compound, and in the step (II), the dicarboxylic acid compound is added in portions.

It is considered that by producing the polyamide-imide-based resin of the present invention by the method of adding the dicarboxylic acid compound in portions, the weight-average molecular weight of the polyamide-imide-based resin can be easily made in the range of 330,000 or more, and it is considered that it is easy to improve the overall quality of the optical film. Light transmittance and elastic modulus, and it is easy to improve the stability of the varnish.

Therefore, the polyamideimide-based resin of the present invention is preferably a resin obtained by a production method in which a dicarboxylic acid compound is added in portions and reacted with a diamine compound, a tetracarboxylic acid compound, and a dicarboxylic acid compound, and more preferably Utilization includes step (I) of reacting a diamine compound with a tetracarboxylic acid compound to produce an intermediate (A), and a step (II) of reacting the intermediate (A) with a dicarboxylic acid compound, and in the step (II) ), the resin obtained by the method for producing the dicarboxylic acid compound was added in portions.

When a polyamidoimide-based resin is produced by the production method including the above-mentioned steps (I) and (II), the reaction of step (I) in which a diamine compound and a tetracarboxylic acid compound are reacted to produce an intermediate (A) The temperature is not particularly limited, but may be, for example, 5 to 200°C, preferably 5 to 100°C, more preferably 5 to 50°C, still more preferably 5°C to room temperature (here, room temperature refers to about 25°C). The reaction time may be, for example, 1 minute to 72 hours, and preferably 10 minutes to 24 hours. In addition, the reaction may be performed in air or under an inert gas atmosphere (eg, nitrogen, argon, etc.) while stirring, and may be performed under normal pressure, pressure, or reduced pressure. In a preferred embodiment, stirring is performed under normal pressure and/or an inert gas atmosphere.

In the step (I), the diamine compound and the tetracarboxylic acid compound are reacted to produce an intermediate (A), that is, a polyamic acid. Therefore, the intermediate (A) has at least a structural unit derived from a diamine compound and a structural unit derived from a tetracarboxylic acid compound.

Next, in the step (II), the intermediate (A) is reacted with a dicarboxylic acid compound, and here, the dicarboxylic acid compound is preferably added in portions. The dicarboxylic acid compound is added in portions to the reaction liquid obtained in the step (I), and the intermediate (A) and the dicarboxylic acid compound are reacted. The molecular weight of the polyamideimide-based resin can be easily adjusted within the above-mentioned preferred range by adding the dicarboxylic acid compound in portions rather than at one time. It should be noted that, in this specification, the term "division addition" refers to dividing the dicarboxylic acid compound to be added in several times, and more specifically, it means dividing the dicarboxylic acid to be added into a specific amount at predetermined intervals. Or add them separately at a specified time. Since the specified interval (specified time) also includes a very short interval or time, the fractional addition also includes continuous addition or continuous feeding.

In the step (II), the number of divisions when adding the dicarboxylic acid compound in portions can be appropriately selected according to the scale of the reaction, the kind of raw materials, etc., but is preferably 2 to 20 times, more preferably 3 to 10 times, and still more preferably 3 to 30 times. 6 times. It is considered that the most suitable structure for improving the elastic modulus while maintaining the transmittance of the optical film is likely to be obtained when the number of classifications is within the above range. In addition, it is considered that it is also easy to adjust the weight average molecular weight of the polyamideimide-based resin within the above-mentioned preferred range.

The dicarboxylic acid compound may be divided into equal amounts and added, or may be divided into unequal amounts and added. The time between each addition action (sometimes called the addition interval) can all be the same or different. In addition, in the case of adding two or more dicarboxylic acid compounds, the term "addition in portions" means dividing and adding the total amount of all the dicarboxylic acid compounds. The division method of each dicarboxylic acid compound is not particularly limited. For example, The respective dicarboxylic acid compounds may be added in one batch or in portions, or the respective dicarboxylic acid compounds may be added in portions together, or a combination of these may be used.

In the step (II), it is preferable to add the polyamide-based resin at a time point when the weight-average molecular weight of the polyamide-based resin becomes preferably 10% or more, more preferably 15% or more with respect to the weight-average molecular weight of the polyamide-based resin to be obtained. The dicarboxylic acid compound is preferably 1 to 40 mol %, more preferably 2 to 25 mol % with respect to the total molar amount of the dicarboxylic acid compound to be added.

The reaction temperature in the step (II) is not particularly limited, but may be, for example, 5 to 200°C, preferably 5 to 100°C, more preferably 5 to 50°C, and further preferably 5 to room temperature (about 25°C). In addition, the reaction may be performed in air or under an inert gas atmosphere (eg, nitrogen, argon, etc.) while stirring, and may be performed under normal pressure, pressure, or reduced pressure. In a preferred embodiment, the step (II) is performed under normal pressure and/or an inert gas atmosphere while stirring.

In the step (II), after the dicarboxylic acid compound is added in portions, a polyamideimide precursor can be obtained by performing stirring for a predetermined time or the like to allow the reaction to proceed. In addition, the polyamide-imide precursor can be isolated, for example, by adding a large amount of water or the like to the reaction liquid containing the polyamide-imide precursor, precipitating the polyamide-imide precursor, and carrying out Filtration, concentration, drying, etc.

In the step (II), the intermediate (A) and the dicarboxylic acid compound are reacted to obtain a polyamideimide precursor. Therefore, the polyamideimide precursor refers to a polyamide before imidization (before ring closure) having at least a structural unit derived from a diamine compound, a structural unit derived from a tetracarboxylic acid, and a structural unit derived from a dicarboxylic acid compound. imide.

In the production of resin, the reaction temperature of the diamine compound, the tetracarboxylic acid compound, and the dicarboxylic acid compound is not particularly limited, but is, for example, 5 to 350°C, preferably 5 to 200°C, and more preferably 5 to 100°C. The reaction time is also not particularly limited, but is, for example, about 30 minutes to 10 hours. The reaction can be carried out in an inert atmosphere or under reduced pressure as necessary. In a preferred embodiment, the reaction is carried out with stirring under normal pressure and/or an inert gas atmosphere. In addition, the reaction is preferably carried out in a solvent inert to the reaction. The solvent is not particularly limited as long as it does not affect the reaction, and examples thereof include water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, 1 -Methoxy-2-propanol, 2-butoxyethanol, propylene glycol monomethyl ether and other alcohol solvents; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone , γ-valerolactone, propylene glycol methyl ether acetate, ethyl lactate and other ester solvents; acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, methyl isobutyl ketone aliphatic hydrocarbon solvents such as pentane, hexane and heptane; alicyclic hydrocarbon solvents such as ethylcyclohexane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; Ether-based solvents such as methoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; amide-based solvents such as N,N-dimethylacetamide, N,N-dimethylformamide, etc.; dimethyl sulfone, dimethyl sulfone, etc. Sulfur-containing solvents such as sulfoxide and sulfolane; carbonate-based solvents such as ethylene carbonate and propylene carbonate; and combinations thereof. Among these, from the viewpoint of solubility, an amide-based solvent can be suitably used.

等脂环式胺(单环式)；氮杂双环[2.2.1]庚烷、氮杂双环[3.2.1]辛烷、氮杂双环[2.2.2]辛烷、及氮杂双环[3.2.2]壬烷等脂环式胺(多环式)；以及吡啶、2-甲基吡啶(2-picoline)、3-甲基吡啶(3-picoline)、4-甲基吡啶(4-picoline)、2-乙基吡啶、3-乙基吡啶、4-乙基吡啶、2,4-二甲基吡啶、2,4,6-三甲基吡啶、3,4-环戊烯并吡啶、5,6,7,8-四氢异喹啉、及异喹啉等芳香族胺。另外，从容易促进酰亚胺化反应的观点考虑，优选不仅使用酰亚胺化催化剂，还使用酸酐。关于酸酐，可举出在酰亚胺化反应中可使用的惯用的酸酐等，作为其具体例，可举出乙酸酐、丙酸酐、丁酸酐等脂肪族酸酐、邻苯二甲酸等芳香族酸酐等。The method for producing a polyamideimide-based resin may further include a step (III) of imidizing the polyamideimide precursor in the presence of an imidization catalyst. By supplying the polyamideimide precursor obtained in the step (II) to the step (III), the structural unit portion having a polyamic acid structure among the structural units of the polyamideimide precursor can be imidized Amination is performed (ring-closing is performed), and the polyamide-imide-type resin containing the structural unit represented by formula (1) and the structural unit represented by formula (2) is obtained. Examples of the imidization catalyst include aliphatic amines such as tripropylamine, dibutylpropylamine, and ethyldibutylamine; N-ethylpiperidine, N-propylpiperidine, N- Butylpyrrolidine, N-butylpiperidine, and N-propylhexahydroazepine

Alicyclic amines (monocyclic); azabicyclo[2.2.1]heptane, azabicyclo[3.2.1]octane, azabicyclo[2.2.2]octane, and azabicyclo[3.2 .2] Alicyclic amines such as nonane (polycyclic); and pyridine, 2-picoline, 3-picoline, 4-picoline ), 2-ethylpyridine, 3-ethylpyridine, 4-ethylpyridine, 2,4-lutidine, 2,4,6-trimethylpyridine, 3,4-cyclopentenopyridine, Aromatic amines such as 5,6,7,8-tetrahydroisoquinoline and isoquinoline. In addition, it is preferable to use not only an imidization catalyst but also an acid anhydride from the viewpoint of easily promoting the imidization reaction. The acid anhydrides include conventional acid anhydrides that can be used in the imidization reaction, and the like, and specific examples thereof include aliphatic acid anhydrides such as acetic anhydride, propionic anhydride, and butyric anhydride, and aromatic acid anhydrides such as phthalic acid. Wait.

Polyamideimide-based resins can be separated (separation and purification) by conventional methods, such as separation means such as filtration, concentration, extraction, crystallization, recrystallization, and column chromatography, or a combination of these separation means. ), in a preferred embodiment, the separation can be carried out by adding a large amount of alcohol such as methanol to the reaction liquid containing the polyamideimide-based resin, precipitating the resin, concentrating, filtering, drying, and the like.

＜Packing＞

The present invention also provides an optical film containing the above-mentioned polyamideimide-based resin. The optical film of the present invention may contain at least one kind of filler. As a filler, an organic particle, an inorganic particle, etc. are mentioned, for example, Preferably, an inorganic particle is mentioned. Examples of inorganic particles include metal oxide particles such as silica, zirconia, alumina, titania, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide, antimony oxide, and cerium oxide, fluoride Metal fluoride particles such as magnesium and sodium fluoride, etc. Among these, from the viewpoints of easily improving the elastic modulus and/or tear strength of the optical film, and easily improving the impact resistance, silica particles, bismuth Zirconia particles, alumina particles, and more preferably silica particles are mentioned. These fillers may be used alone or in combination of two or more.

The average primary particle size of the filler, preferably silica particles is usually 1 nm or more, preferably 5 nm or more, more preferably 10 nm or more, still more preferably 15 nm or more, particularly preferably 20 nm or more, preferably 100 nm or less, and more preferably 90 nm or less , more preferably 80 nm or less, still more preferably 70 nm or less, particularly preferably 60 nm or less, even more preferably 50 nm or less, and even more preferably 40 nm or less. When the average primary particle size of the silica particles is within the above range, aggregation of the silica particles is easily suppressed, and the optical properties of the obtained optical film are easily improved. The average primary particle size of the filler can be measured by the BET method. In addition, the average primary particle diameter can also be measured by the image analysis of a transmission electron microscope and a scanning electron microscope.

When the optical film of the present invention contains a filler, preferably silica particles, the content of the filler is usually 0.1 part by mass or more, preferably 1 part by mass or more, and more preferably 5 parts by mass with respect to 100 parts by mass of the optical film. Above, it is more preferably 10 parts by mass or more, still more preferably 20 parts by mass or more, particularly preferably 30 parts by mass or more, and preferably 60 parts by mass or less. When content of a filler is more than the said minimum, it becomes easy to improve the elastic modulus of the optical film obtained. Moreover, when content of a filler is below the said upper limit, it becomes easy to improve the optical characteristics of an optical film.

＜Ultraviolet absorber＞

The optical film of this invention may contain at least 1 type of ultraviolet absorber. The ultraviolet absorber can be appropriately selected from those generally used as ultraviolet absorbers in the field of resin materials. The ultraviolet absorber may contain a compound that absorbs light having a wavelength of 400 nm or less. Examples of the ultraviolet absorber include at least one compound selected from the group consisting of benzophenone-based compounds, salicylate-based compounds, benzotriazole-based compounds, and triazine-based compounds. An ultraviolet absorber can be used individually or in combination of 2 or more types. Since deterioration of resin can be suppressed by containing an ultraviolet absorber in an optical film, when applying the optical film of this invention to a display apparatus etc., visibility can be improved. In this specification, the "system compound" refers to a derivative of the compound to which the "system compound" is attached. For example, the "benzophenone-based compound" refers to a compound having benzophenone as a parent skeleton and a substituent bonded to the benzophenone.

When the optical film of the present invention contains an ultraviolet absorber, the content of the ultraviolet absorber is preferably 0.01 to 10 parts by mass, and more preferably 1 to 10 parts by mass relative to the mass of the polyamideimide-based resin contained in the optical film. 8 parts by mass, more preferably 2 to 7 parts by mass. When content of an ultraviolet absorber is more than the said minimum, it becomes easy to improve ultraviolet absorbency. When the content of the ultraviolet absorber is below the above-mentioned upper limit, decomposition of the ultraviolet absorber due to heat during production of the base material can be suppressed, and optical properties can be easily improved, for example, haze can be easily reduced.

＜Other additives＞

The optical film of the present invention may further contain other additives other than fillers and ultraviolet absorbers. Examples of other additives include antioxidants, mold release agents, stabilizers, and colorants such as bluing agents, flame retardants, pH adjusters, silica dispersants, lubricants, thickeners, and leveling agents. Wait. When other additives are contained, the content thereof may be preferably 0.001 to 20 parts by mass, more preferably 0.01 to 15 parts by mass, and even more preferably 0.1 to 10 parts by mass with respect to the mass of the optical film.

(Manufacturing method of optical film)

The method for producing an optical film using the polyamideimide-based resin of the present invention is not particularly limited, and for example, it may be a production method including the following steps:

(a) a step of preparing a polyamide-imide-based resin varnish containing at least the polyamide-imide-based resin and a solvent (varnish preparation step),

(b) a step of applying a varnish to a support material to form a coating film (coating step), and

(c) A step of drying the applied liquid (coating film) to form an optical film (optical film forming step).

In addition, this invention also provides the polyamide-imide-type resin varnish containing at least the polyamide-imide-type resin of this invention and a solvent.

In the varnish preparation step, a varnish is prepared by dissolving the polyamideimide-based resin in a solvent, adding additives such as the aforementioned filler and an ultraviolet absorber as necessary, and stirring and mixing. It should be noted that, when silica particles are used as the filler, the following silica sol can be added to the resin, and the silica sol can be used in the preparation of the following varnish with a solvent that can dissolve the aforementioned resin, for example A silica sol obtained by substituting a solvent for a dispersion of silica sol containing silica particles.

The solvent used in the preparation of the varnish is not particularly limited as long as it can dissolve the aforementioned resin. Examples of the solvent include amide-based solvents such as N,N-dimethylacetamide and N,N-dimethylformamide; lactones such as γ-butyrolactone (GBL) and γ-valerolactone. Sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide, and sulfolane; carbonate-based solvents such as ethylene carbonate and propylene carbonate; and their combinations (mixed solvents). Among these, an amide-based solvent or a lactone-based solvent is preferable. When a lactone-based solvent is used, it tends to be a film with high optical properties. These solvents may be used alone or in combination of two or more. In addition, water, an alcohol-based solvent, a ketone-based solvent, an acyclic ester-based solvent, an ether-based solvent, and the like may be contained in the varnish. The solid content concentration in the polyamideimide-based resin varnish of the present invention is preferably 1 to 25% by mass, and more preferably 5 to 20% by mass, from the viewpoint of easily improving the stability of the polyamideimide-based resin varnish. , more preferably 5 to 15 mass %. In addition, the concentration of the solvent in the polyamide-imide-based resin varnish of the present invention is based on the total amount of the polyamide-imide-based resin varnish from the viewpoint of easily improving the stability of the polyamide-imide-based resin varnish. More preferably, it is 75-99 mass %, More preferably, it is 80-95 mass %, More preferably, it is 85-95 mass %.

The polyamide-imide-based resin varnish containing at least the polyamide-imide-based resin of the present invention and a solvent has high stability. When an optical film containing a polyamide-based resin is produced using a varnish containing a polyamide-imide-based resin, the coating process may be performed immediately after the varnish preparation process, but the prepared varnish may be performed after the varnish preparation process. A predetermined time elapses before the coating process due to short-term storage, transportation, and the like. When the gelatinization of the varnish occurs during the period after the varnish preparation step and before the coating step, sufficient coatability may not be obtained in the coating step. In addition, the quality of the optical film, especially the optical properties, may be impaired by the gel in the varnish. Since the polyamideimide-based resin varnish of the present invention has high stability, the above-mentioned problems are less likely to occur. In addition, in this specification, the polyamideimide-based resin varnish has high stability, and therefore, even if it is allowed to stand at room temperature (for example, 25° C.), it is preferable to stand still for 1 day or more, more preferably 3 days or more, and further Preferably 10 days or more, particularly preferably 30 days or more, gelation of the resin varnish does not occur. In addition, when using the varnish containing the polyamide-imide precursor which can form the polyamide-imide-type resin of this invention through imidization, the optical fiber containing the polyamide-imide-type resin of this invention is produced. In the case of a film, a varnish including at least a polyamideimide precursor and a solvent before imidization capable of forming the polyamideimide-based resin of the present invention also has high stability.

In the coating step, the varnish is coated on the support material by a known coating method to form a coating film. Examples of known coating methods include bar coating, reverse coating, gravure coating, and other roll coating methods, die coating, comma coating, lip coating, spin coating, and screen coating. Coating method, spray coating method, dipping method, spray method, tape casting method, etc.

In the film forming step, an optical film can be formed by drying the coating film and peeling it from the support material. After peeling, a step of drying the optical film may be further provided. Drying of the coating film can usually be performed at a temperature of 50 to 350°C. If necessary, drying of the coating film can be performed in an inert atmosphere or under reduced pressure.

As an example of a support material, if it is a metal type, a SUS plate is mentioned, and if it is a resin type, a PET film, a PEN film, a polyamide type resin film, a polyimide type resin film, and a cycloolefin type are mentioned. Polymer (COP) film, acrylic film, etc. Among them, a PET film, a COP film, etc. are preferable from the viewpoints of being excellent in smoothness and heat resistance, and a PET film is more preferable from the viewpoints of adhesiveness to an optical film and cost.

The use of the optical film of the present invention is not particularly limited, and it can be used for various uses. As described above, the optical film of the present invention may be a single layer or a laminate, and the optical film of the present invention may be used as it is, or may be used as a laminate with other films. In addition, when an optical film is a laminated body, it is called an optical film including all layers laminated|stacked on one surface or both surfaces of an optical film.

(functional layer)

One or more functional layers may be laminated on at least one surface of the optical film of the present invention. As a functional layer, an ultraviolet absorption layer, a hard coat layer, a primer layer, a gas barrier layer, an adhesive layer, a hue adjustment layer, a refractive index adjustment layer etc. are mentioned, for example. The functional layers may be used alone or in combination of two or more.

The ultraviolet absorbing layer is a layer having an ultraviolet absorbing function, for example, it is composed of a main material selected from the group consisting of an ultraviolet curable transparent resin, an electron beam curable transparent resin, and a thermosetting transparent resin, and a material dispersed in the main material. UV absorber composition.

A hard coat layer may be provided on at least one surface of the optical film of the present invention. The thickness of the hard coat layer is not particularly limited, and may be, for example, 2 to 100 μm. When the thickness of the hard coat layer is within the above-mentioned range, sufficient scratch resistance is ensured, and bending resistance is not easily reduced, and the problem of curling due to curing shrinkage tends to be less likely to occur.

The aforementioned hard coat layer can be formed by irradiating an active energy ray or imparting thermal energy to cure a hard coat layer composition containing a reactive material capable of forming a crosslinked structure; preferably by irradiating an active energy ray. Active energy rays are defined as energy rays capable of decomposing active species-generating compounds to generate active species, and examples thereof include visible light, ultraviolet rays, infrared rays, X-rays, alpha rays, beta rays, gamma rays, and electron beams, and preferably include out UV rays. The said hard-coat layer composition contains at least 1 sort(s) of polymer from a radically polymerizable compound and a cationically polymerizable compound.

The aforementioned radically polymerizable compound is a compound having a radically polymerizable group. The radically polymerizable group contained in the above-mentioned radically polymerizable compound may be any functional group capable of generating a radical polymerization reaction, and examples thereof include a carbon-carbon unsaturated double bond-containing group, and the like. Specifically, A vinyl group, a (meth)acryloyl group, etc. are mentioned. In addition, when the said radically polymerizable compound has two or more radically polymerizable groups, these radically polymerizable groups may be respectively the same or different. The number of radically polymerizable groups that the radically polymerizable compound has in one molecule is preferably 2 or more from the viewpoint of improving the hardness of the hard coat layer. As the above-mentioned radically polymerizable compound, a compound having a (meth)acryloyl group is preferably used from the viewpoint of high reactivity, and specifically, a compound having 2 to 6 (methyl) groups in one molecule is used. Acryloyl compound called polyfunctional acrylate monomer, called epoxy (meth)acrylate, urethane (meth)acrylate, polyester (meth)acrylate The molecular weight of the oligomer having several (meth)acryloyl groups in the molecule is several hundred to several thousand, preferably selected from epoxy (meth)acrylate, urethane (meth)acrylate and polyacrylate. One or more of ester (meth)acrylates.

The aforementioned cationically polymerizable compound is a compound having a cationically polymerizable group such as an epoxy group, an oxetanyl group, and a vinyl ether group. From the viewpoint of improving the hardness of the hard coat layer, the number of cationically polymerizable groups contained in one molecule of the cationically polymerizable compound is preferably 2 or more, and more preferably 3 or more.

In addition, among the above-mentioned cationically polymerizable compounds, compounds having at least one of an epoxy group and an oxetanyl group as a cationically polymerizable group are preferable. Cyclic ether groups such as an epoxy group and an oxetanyl group are preferable from the viewpoint of small shrinkage accompanying the polymerization reaction. In addition, the compound having an epoxy group in the cyclic ether group has the following advantages: it is easy to obtain compounds of various structures, does not adversely affect the durability of the obtained hard coat layer, and is easy to control the interaction with radicals Compatibility of polymeric compounds. In addition, the oxetanyl group in the cyclic ether group has the following advantages compared with the epoxy group: the degree of polymerization is easily increased, the toxicity is low, and the network obtained from the cationically polymerizable compound of the hard coat layer obtained is accelerated. The rate of formation, even in the region where it is mixed with the radical polymerizable compound, does not leave unreacted monomers in the film to form an independent network; and the like.

Examples of the cationically polymerizable compound having an epoxy group include polyglycidyl ether of a polyhydric alcohol having an alicyclic ring, or cyclohexene-containing cyclohexene treated with an appropriate oxidizing agent such as hydrogen peroxide or peroxyacid Alicyclic epoxy resins obtained by epoxidizing compounds of rings and cyclopentene rings; polyglycidyl ethers of aliphatic polyols or their oxyalkylene adducts, polyglycidyl groups of aliphatic long-chain polyacids Aliphatic epoxy resins such as homopolymers and copolymers of esters and glycidyl (meth)acrylates; bisphenols such as bisphenol A, bisphenol F, hydrogenated bisphenol A, or their alkylene oxide adducts , derivatives such as caprolactone adducts, glycidyl ethers produced by the reaction with epichlorohydrin, and glycidyl ether epoxy resins derived from bisphenols such as Novolac epoxy resins.

The aforementioned hard coat composition may further contain a polymerization initiator. As a polymerization initiator, a radical polymerization initiator, a cationic polymerization initiator, a radical and a cationic polymerization initiator, etc. are mentioned, It can select and use suitably. These polymerization initiators can be decomposed by at least one of active energy ray irradiation and heating to generate radicals or cations, and to perform radical polymerization and cationic polymerization.

The radical polymerization initiator should just be capable of releasing a substance that initiates radical polymerization by at least one of active energy ray irradiation and heating. For example, as a thermal radical polymerization initiator, organic peroxides, such as hydrogen peroxide and peroxybenzoic acid, azo compounds, such as azobisbutyronitrile, etc. are mentioned.

As active energy ray radical polymerization initiators, there are Type 1 type radical polymerization initiators that generate radicals by decomposition of molecules, and Type 2 type radical polymerization initiators that generate radicals by hydrogen abstraction reaction in coexistence with tertiary amines , they can be used alone or in combination.

The cationic polymerization initiator should just be capable of releasing a substance that initiates cationic polymerization by at least one of active energy ray irradiation and heating. As the cationic polymerization initiator, an aromatic iodonium salt, an aromatic sulfonium salt, a cyclopentadienyl iron (II) complex, or the like can be used. Depending on the difference in structure, they can initiate cationic polymerization by either or both of active energy ray irradiation or heating.

The polymerization initiator may preferably be contained in an amount of 0.1 to 10% by mass with respect to 100% by mass of the entire hard coat composition. When the content of the polymerization initiator is within the above-mentioned range, curing can be sufficiently advanced, the mechanical properties and adhesive force of the finally obtained coating film can be kept in a favorable range, and there is adhesive force due to curing shrinkage. Defects, cracking, and curling tend to be less likely to occur.

The aforementioned hard coat layer composition may further contain at least one selected from the group consisting of a solvent and an additive. The above-mentioned solvent may be a solvent that can dissolve or disperse the above-mentioned polymerizable compound and polymerization initiator, and is known as a solvent for a hard coat composition in this technical field, within a range that does not hinder the effects of the present invention. used within. The aforementioned additives may further contain inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, antifouling agents, and the like.

The adhesive layer is a layer having an adhesive function, and has a function of adhering the optical film to other members. As the material for forming the adhesive layer, commonly known materials can be used. For example, a thermosetting resin composition or a photocurable resin composition can be used. In this case, the resin composition can be polymerized and cured by supplying energy afterwards.

The adhesive layer may be a layer called a pressure-sensitive adhesive (PSA), which is attached to an object by pressing. The pressure-sensitive adhesive may be an adhesive that "has adhesive properties at room temperature and adheres to a material to be adhered with light pressure" (JIS K 6800), or may be a "specified component". Capsule-type adhesives that are contained in a protective film (microcapsule) and maintain stability until the film is destroyed by appropriate means (pressure, heat, etc.)" (JIS K 6800).

A hue adjustment layer is a layer which has a hue adjustment function, and is a layer which can adjust the laminated body containing an optical film to a target hue. The hue-adjusting layer is, for example, a layer containing a resin and a colorant. Examples of the colorant include inorganic pigments such as titanium oxide, zinc oxide, red iron oxide, titanium oxide-based fired pigments, ultramarine blue, cobalt aluminate, and carbon black; azo-based compounds and quinacridone-based compounds , organic pigments such as anthraquinone-based compounds, perylene-based compounds, isoindolinone-based compounds, phthalocyanine-based compounds, quinophthalone-based compounds, threne-based compounds, and diketopyrrolopyrrole-based compounds; sulfuric acid Barium, calcium carbonate and other extender pigments; and basic dyes, acid dyes, and mordant dyes and other dyes.

The refractive index adjusting layer is a layer having a function of adjusting the refractive index, and is, for example, a layer having a refractive index different from that of the optical film and capable of imparting a predetermined refractive index to the optical laminate. The refractive index adjustment layer may be, for example, a resin layer containing appropriately selected resin and, in some cases, a pigment, or may be a metal thin film. Examples of pigments for adjusting the refractive index include silica, alumina, antimony oxide, tin oxide, titanium oxide, zirconium oxide, and tantalum oxide. The average primary particle size of the pigment may be 0.1 μm or less. By setting the average primary particle diameter of the pigment to be 0.1 μm or less, diffuse reflection of light transmitted through the refractive index adjustment layer can be prevented, and a decrease in transparency can be prevented. Examples of metals that can be used in the refractive index adjusting layer include titanium oxide, tantalum oxide, zirconium oxide, zinc oxide, tin oxide, silicon oxide, indium oxide, titanium oxynitride, titanium nitride, silicon oxynitride, and nitride. Metal oxides or metal nitrides such as silicon.

The optical film of the present invention may be a single layer or a laminate. For example, the optical film produced as described above may be used as it is, or may be used as a laminate with other films.

In one embodiment of the present invention, the optical film may have a protective film on at least one side (one side or both sides). For example, when the optical film has a functional layer on one surface, the protective film may be laminated on the optical film side surface or the functional layer side surface, or may be laminated on both the optical film side and the functional layer side. When the optical film has functional layers on both surfaces, the protective film may be laminated on the surface on the side of one functional layer, or may be laminated on the surface on the side of both functional layers. The protective film is a film for temporarily protecting the surface of the optical film or the functional layer, and is not particularly limited as long as it is a peelable film that can protect the surface of the optical film or the functional layer. Examples of the protective film include polyester-based resin films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyethylene, polypropylene films, and the like The polyolefin-based resin film, the acrylic resin film, and the like are preferably selected from the group consisting of a polyolefin-based resin film, a polyethylene terephthalate-based resin film, and an acrylic resin film. When an optical film has two protective films, each protective film may be the same or different.

The thickness of the protective film is not particularly limited, but is usually 10 to 120 μm, preferably 15 to 110 μm, and more preferably 20 to 100 μm. When an optical film has two protective films, the thickness of each protective film may be the same or different.

In a preferred embodiment of the present invention, the optical film of the present invention is useful as a front panel of a display device, particularly a front panel of a flexible display device (hereinafter, sometimes referred to as a window film). A flexible display device has, for example, a flexible functional layer and an optical film laminated on the flexible functional layer and functioning as a front panel. That is, the front panel of the flexible display device is arranged on the viewing side on the flexible functional layer. The front panel has the function of protecting the flexible functional layer.

Examples of display devices include televisions, smartphones, mobile phones, car navigation, tablet PCs, portable game consoles, electronic paper, indicators, bulletin boards, clocks, and wearable devices such as smart watches. Examples of the flexible display device include all display devices having flexible properties, particularly preferably a bendable, foldable display device, and a rollable display device.

[Flexible Display Device]

The present invention also provides a flexible display device including the optical film of the present invention. The optical film of the present invention is preferably used in a flexible display device as a front panel, which is sometimes referred to as a window film. The flexible display device is formed of a laminate for a flexible display device and an organic EL display panel, and the laminate for a flexible display device is arranged on the viewing side of the organic EL display panel and is configured to be foldable. The laminate for a flexible display device may contain a window film, a polarizing plate (preferably a circular polarizing plate), and a touch sensor, and the lamination order of these may be arbitrary, but the order of the window film, polarizing plate, touch sensor, or window is preferred from the viewing side The film, the touch sensor, and the polarizing plate are stacked in this order. When a polarizing plate is present on the viewing side of the touch sensor, the pattern of the touch sensor is difficult to be observed, and the visibility of the displayed image becomes good, which is preferable. The respective members may be laminated using an adhesive, an adhesive, or the like. In addition, a light-shielding pattern formed on at least one surface of any one of the above-mentioned window film, polarizing plate, and touch sensor may be provided.

[polarizing plate]

The flexible display device of the present invention may further include a polarizing plate, preferably a circular polarizing plate. The circularly polarizing plate is a functional layer having a function of transmitting only a right-handed or left-handed circularly polarized light component by stacking a λ/4 retardation plate on a linearly polarizing plate. For example, it can be used to convert external light into right-handed circularly polarized light, block the external light that is reflected by the organic EL panel and become left-handed circularly polarized light, and only transmit the light-emitting component of the organic EL, thereby suppressing the influence of reflected light , thereby making it easy to view the image. In order to achieve the function of circularly polarized light, the absorption axis of the linear polarizer and the slow axis of the λ/4 retardation plate need to be 45° in theory, but 45±10° in practical applications. The linear polarizer and the λ/4 retardation plate do not necessarily have to be stacked adjacent to each other, and the relationship between the absorption axis and the slow axis may satisfy the aforementioned range. It is preferable to achieve complete circularly polarized light at all wavelengths, but this is not necessary in practical applications. Therefore, the circularly polarizing plate in the present invention also includes an elliptically polarizing plate. It is also preferable that a λ/4 retardation film is further laminated on the viewing side of the linear polarizing plate to make the outgoing light circularly polarized, thereby improving visibility in a state of wearing polarized sunglasses.

The linear polarizer is a functional layer having a function of passing light vibrating in the direction of the transmission axis and blocking polarized light of a vibration component perpendicular thereto. The linear polarizer may be a single linear polarizer or a structure including a linear polarizer and a protective film bonded to at least one surface of the linear polarizer. The thickness of the linear polarizing plate may be 200 μm or less, and preferably 0.5 to 100 μm. When the thickness is within the aforementioned range, there is a tendency that the flexibility is not easily reduced.

The aforementioned linear polarizer may be a film-type polarizer produced by dyeing and stretching a polyvinyl alcohol (PVA)-based film. The polarizing performance can be exhibited by adsorbing a dichroic dye such as iodine on the PVA-based film oriented by stretching, or by stretching the dichroic dye in a state of being adsorbed on PVA to orient the dichroic dye. In the production of the above-mentioned film-type polarizer, steps such as swelling, crosslinking by boric acid, washing by aqueous solution, and drying may be further included. The stretching and dyeing process may be performed as a PVA-based film alone, or may be performed in a state of being laminated with another film such as polyethylene terephthalate. The thickness of the PVA-type film to be used is preferably 10 to 100 μm, and the stretching ratio is preferably 2 to 10 times.

Moreover, as another example of the said polarizer, the liquid crystal coating type polarizer formed by apply|coating a liquid crystal polarizing composition may be sufficient. The liquid crystal polarizing composition may contain a liquid crystal compound and a dichroic dye compound. The above-mentioned liquid crystalline compound only needs to have a property of exhibiting a liquid crystal state, and it is preferable that it exhibits a high polarization performance especially when it has a high-order alignment state such as smectic. In addition, the liquid crystal compound preferably has a polymerizable functional group.

The dichroic dye is a dye that is aligned together with the liquid crystal compound and exhibits dichroism, and the dichroic dye itself may have liquid crystallinity or a polymerizable functional group. Any compound in the liquid crystal polarizing composition has a polymerizable functional group.

The aforementioned liquid crystal polarizing composition may further contain an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like.

The said liquid crystal polarizing layer is manufactured by apply|coating a liquid crystal polarizing composition on an alignment film, and forming a liquid crystal polarizing layer.

Compared with the film-type polarizer, the liquid crystal polarizing layer can be formed with a thinner thickness. The thickness of the liquid crystal polarizing layer may preferably be 0.5 to 10 μm, and more preferably 1 to 5 μm.

The said alignment film can be manufactured by apply|coating an alignment film forming composition on a base material, and providing orientation by rubbing, polarized light irradiation, etc., for example. The composition for forming an alignment film may contain, in addition to the alignment agent, a solvent, a crosslinking agent, an initiator, a dispersing agent, a leveling agent, a silane coupling agent, and the like. As the aforementioned alignment agent, for example, polyvinyl alcohols, polyacrylates, polyamic acids, and polyimides can be used. In the case of applying photo-alignment, an alignment agent containing a cinnamate group is preferably used. The weight average molecular weight of the polymer which can be used as the said alignment agent may be about 10,000-1,000,000. From the viewpoint of the alignment regulating force, the thickness of the alignment film is preferably 5 to 10,000 nm, and more preferably 10 to 500 nm. The liquid crystal polarizing layer may be laminated after being peeled from the base material, or the base material may be directly laminated. It is also preferable that the base material functions as a transparent base material for a protective film, a retardation plate, and a window.

As said protective film, what is necessary is just to be a transparent polymer film, and the material and additive which can be used for the said transparent base material can be used. Cellulose-based films, olefin-based films, acrylic-based films, and polyester-based films are preferred. It may be a coating-type protective film obtained by coating and curing a cationic curing composition such as epoxy resin or a radical curing composition such as acrylate. If necessary, plasticizers, ultraviolet absorbers, infrared absorbers, pigments, colorants such as dyes, optical brighteners, dispersants, heat stabilizers, light stabilizers, antistatic agents, antioxidants, and lubricants may be contained , solvent, etc. The thickness of the said protective film may be 200 micrometers or less, Preferably it is 1-100 micrometers. When the thickness of the said protective film is in the said range, the flexibility of a protective film is hard to fall. The protective film may also function as a transparent substrate for the window.

The aforementioned λ/4 retardation plate is a film that provides a retardation of λ/4 in the direction perpendicular to the advancing direction of the incident light (the in-plane direction of the film). The aforementioned λ/4 retardation plate may be a stretched retardation plate produced by stretching a polymer film such as a cellulose-based film, an olefin-based film, and a polycarbonate-based film. As needed, retardation modifiers, plasticizers, ultraviolet absorbers, infrared absorbers, pigments, colorants such as dyes, optical brighteners, dispersants, heat stabilizers, light stabilizers, antistatic agents, Antioxidants, lubricants, solvents, etc. The thickness of the stretched retardation plate may be 200 μm or less, and preferably 1 to 100 μm. When the thickness is within the aforementioned range, there is a tendency that the flexibility of the film is less likely to decrease.

Moreover, as another example of the said λ/4 retardation plate, the liquid crystal coating-type retardation plate formed by apply|coating a liquid crystal composition may be sufficient. The liquid crystal composition includes a liquid crystal compound having a property of exhibiting a liquid crystal state such as nematic, cholesteric, and smectic. Any compound including a liquid crystal compound in the liquid crystal composition has a polymerizable functional group. The aforementioned liquid crystal coating type retardation plate may further contain an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like. The said liquid crystal coating-type retardation plate can be manufactured by apply|coating a liquid crystal composition on an alignment film, and hardening, and forming a liquid crystal retardation layer similarly to the description of the said liquid crystal polarizing layer. Compared with the stretched retardation film, the liquid crystal coated retardation film can be formed with a thinner thickness. The thickness of the liquid crystal polarizing layer can be usually 0.5 to 10 μm, preferably 1 to 5 μm. The said liquid crystal coating type retardation plate may be laminated|stacked by transfer after peeling from a base material, and the said base material may be laminated|stacked as it is. It is also preferable that the base material functions as a transparent base material for a protective film, a retardation plate, and a window.

In general, the shorter the wavelength, the greater the birefringence, and the longer the wavelength, the smaller the birefringence is, there are many materials. In this case, since the retardation of λ/4 cannot be achieved in the entire visible light region, it is often designed so that the in-plane retardation becomes 100 to 180 nm, preferably 130 to 150 nm, such that the in-plane retardation becomes λ/4 in the vicinity of 560 nm, where the visibility is high. . It is preferable to use a reverse dispersion λ/4 retardation plate using a material having a birefringence wavelength dispersion characteristic opposite to that of usual, since visibility can be improved. As such a material, also in the case of a stretched retardation plate, it is preferable to use the material described in Japanese Patent Laid-Open No. 2007-232873, etc., and in the case of a liquid crystal coating type retardation plate, it is preferable to use the The material described in the publication No. 2010-30979.

In addition, as another method, a technique for obtaining a wide-band λ/4 phase difference plate by combining with a λ/2 phase difference plate is also known (Japanese Patent Laid-Open No. 10-90521). The λ/2 retardation plate can also be manufactured using the same material method as the λ/4 retardation plate. The combination of a stretched retardation plate and a liquid crystal coating type retardation plate is arbitrary, and it is preferable to use a liquid crystal coating type retardation plate because the thickness can be reduced.

For the aforementioned circularly polarizing plate, in order to improve the visibility in the oblique direction, a method of laminating a positive C plate is also known (Japanese Patent Laid-Open No. 2014-224837). The positive C plate can also be a liquid crystal coating type retardation plate or a stretched type retardation plate. The retardation in the thickness direction is usually -200 to -20 nm, preferably -140 to -40 nm.

[touch sensor]

The flexible display device of the present invention may further include a touch sensor. A touch sensor can be used as an input mechanism. As the touch sensor, various methods such as a resistive film method, a surface acoustic wave method, an infrared method, an electromagnetic induction method, and an electrostatic capacitance method have been proposed, and any method may be used. Among them, the electrostatic capacitance method is preferable. The capacitive touch sensor can be divided into an active area and an inactive area located at the periphery of the active area. The active area is an area corresponding to an area (display portion) on the display panel that displays a screen, and is an area that senses the user's touch, and the inactive area is an area corresponding to an area (non-display portion) of the display device that does not display a screen. The touch sensor may include: a substrate having flexible properties; a sensing pattern formed on an active area of the substrate; and an inactive area formed on the substrate for connecting the sensing pattern with the sensing pattern via a pad portion Each sensing line connected to an external drive circuit. As the substrate having flexible properties, the same material as the transparent substrate of the aforementioned window can be used. The substrate of the touch sensor preferably has a toughness of 2,000 MPa% or more from the viewpoint of suppressing cracks in the touch sensor. The toughness may be more preferably 2,000 to 30,000 MPa%. Here, toughness is defined as the lower area of the curve up to the point of failure in a stress (MPa)-strain (%) curve (Stress-strain curve) obtained by a tensile test of a polymer material.

The sensing pattern may include a first pattern formed along the first direction and a second pattern formed along the second direction. The first pattern and the second pattern are arranged in mutually different directions. The first pattern and the second pattern are formed on the same layer, and in order to sense the touched position, the patterns must be electrically connected. The first pattern has a configuration in which the unit patterns are connected to each other through joints, and the second pattern has a configuration in which the unit patterns are separated from each other in an island form. Therefore, separate bridge electrodes are required to electrically connect the second patterns. A known transparent electrode raw material can be applied to the sensing pattern. For example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), indium gallium zinc oxide (IGZO), cadmium tin oxide ( CTO), PEDOT (poly(3,4-ethylenedioxythiophene), poly(3,4-ethylenedioxythiophene)), carbon nanotubes (CNT), graphene, wire, etc., which can be used alone or mixed 2 Use more than one species. Preferably ITO can be used. The metal that can be used for the wire is not particularly limited, and examples thereof include silver, gold, aluminum, copper, iron, nickel, titanium, selenium, chromium, and the like. These can be used individually or in mixture of 2 or more types.

The bridge electrode may be formed on the upper part of the above-mentioned insulating layer via an insulating layer on the upper part of the sensing pattern, and the bridge electrode may be formed on the substrate, and the insulating layer and the sensing pattern may be formed thereon. The bridge electrode may be formed of the same material as the sensing pattern, or may be formed of a metal such as molybdenum, silver, aluminum, copper, palladium, gold, platinum, zinc, tin, titanium, or an alloy of two or more of these. The first pattern and the second pattern must be electrically insulated, so an insulating layer is formed between the sensing pattern and the bridge electrode. The insulating layer may be formed only between the contact of the first pattern and the bridge electrode, or may be formed to cover the layer of the sensing pattern. In the latter case, the bridge electrode may connect the second pattern through a contact hole formed in the insulating layer. In the aforementioned touch sensor, as a method for appropriately compensating the difference in transmittance between the patterned area and the non-patterned area (specifically, the transmittance caused by the difference in refractive index in these areas) An optical adjustment layer may be further included between the substrate and the electrode, and the optical adjustment layer may include an inorganic insulating substance or an organic insulating substance. The optical adjustment layer can be formed by apply|coating the photocurable composition containing a photocurable organic binder and a solvent on a board|substrate. The aforementioned photocurable composition may further contain inorganic particles. The refractive index of the optical adjustment layer can be increased by the aforementioned inorganic particles.

The said photocurable organic binder can contain the copolymer of each monomer, such as an acrylate type monomer, a styrene type monomer, and a carboxylic acid type monomer, for example. The aforementioned photocurable organic binder may be, for example, a copolymer containing repeating units different from each other, such as an epoxy group-containing repeating unit, an acrylate repeating unit, and a carboxylic acid repeating unit.

The aforementioned inorganic particles may contain, for example, zirconium dioxide particles, titanium dioxide particles, alumina particles, and the like. The said photocurable composition may further contain each additive, such as a photoinitiator, a polymerizable monomer, and a curing adjuvant.

[adhesive layer]

Each layer (window, polarizer, touch sensor) forming the laminate for a flexible display device and film members (linear polarizer, λ/4 retardation plate, etc.) constituting each layer can be bonded by an adhesive. As the adhesive, water-based adhesives, organic solvent-based adhesives, solvent-free adhesives, solid adhesives, solvent-volatile adhesives, water-based solvent-volatile adhesives, and moisture-curable adhesives can be used. Adhesives, heat-curable adhesives, anaerobic-curable adhesives, active energy ray-curable adhesives, curing agent-mixed adhesives, hot-melt adhesives, pressure-sensitive adhesives ( Adhesives), re-wet adhesives and other commonly used adhesives. Among them, water-based solvent-volatile adhesives, active energy ray-curable adhesives, and adhesives are commonly used. The thickness of the adhesive layer can be appropriately adjusted according to the required adhesive force and the like, and is, for example, 0.01 to 500 μm, preferably 0.1 to 300 μm. The adhesive layer may exist in a plurality of layers in the laminate for a flexible display device, and the thickness of each layer and the type of the adhesive used may be the same or different.

As the aforementioned water-based solvent-volatile adhesive, polyvinyl alcohol-based polymers, water-soluble polymers such as starch, and polymers in a water-dispersed state such as ethylene-vinyl acetate-based emulsions and styrene-butadiene-based emulsions can be used. main agent polymer. In addition to water and the aforementioned main ingredient polymer, a cross-linking agent, a silane-based compound, an ionic compound, a cross-linking catalyst, an antioxidant, a dye, a pigment, an inorganic filler, an organic solvent, and the like may be blended. In the case of adhering with the aforementioned water-based solvent-volatile adhesive, the aforementioned water-based solvent-volatile adhesive can be injected between the layers to be adhered, and the layers to be bonded can be pasted together and then dried to provide adhesion. sex. The thickness of the adhesive layer in the case of using the aforementioned water-based solvent-volatile adhesive may be 0.01 to 10 μm, preferably 0.1 to 1 μm. When the aforementioned water-based solvent-volatile adhesive is used for the formation of multiple layers, the thickness of each layer and the type of the aforementioned adhesive may be the same or different.

The aforementioned active energy ray-curable adhesive can be formed by curing an active energy ray-curable composition containing a reactive material capable of forming an adhesive layer by irradiating an active energy ray. The said active energy ray hardening composition may contain the polymer of at least 1 sort(s) of radical polymerizable compound and cationic polymerizable compound similar to a hard-coat composition. The aforementioned radically polymerizable compound can be used in the same manner as the hard coat composition, and the same type of radical polymerizable compound as the hard coat composition can be used. As a radical polymerizable compound which can be used for an adhesive layer, the compound which has an acryl group is preferable. In order to reduce the viscosity as an adhesive composition, it is also preferable to contain a monofunctional compound.

The aforementioned cationically polymerizable compound is the same as that of the hard coat layer composition, and the same kind of cationically polymerizable compound as the hard coat layer composition can be used. As the cationically polymerizable compound that can be used in the active energy ray-curable composition, an epoxy compound is preferable. In order to reduce the viscosity of an adhesive composition, it is also preferable to contain a monofunctional compound as a reactive diluent.

In the active energy ray composition, a polymerization initiator may be further contained. The polymerization initiator includes a radical polymerization initiator, a cationic polymerization initiator, a radical and a cationic polymerization initiator, and the like, which can be appropriately selected and used. These polymerization initiators can be decomposed by at least one of active energy ray irradiation and heating to generate radicals or cations, thereby enabling radical polymerization and cationic polymerization to proceed. An initiator capable of initiating at least any one of radical polymerization and cationic polymerization by active energy ray irradiation described in the description of the hard coat composition can be used.

The aforementioned active energy ray-curable composition may further contain an ion trapping agent, an antioxidant, a chain transfer agent, an adhesion imparting agent, a thermoplastic resin, a filler, a fluid viscosity modifier, a plasticizer, an antifoaming agent, an additive, and a solvent. In the case of bonding with the active energy ray-curable adhesive, the bonding can be performed by applying the active energy ray-curable composition to one or both of the layers to be adhered, and then bonding, An active energy ray is irradiated through one to-be-adhered layer or both to-be-adhered layers, and it hardens|cures. The thickness of the adhesive layer when the active energy ray-curable adhesive is used may be 0.01 to 20 μm, preferably 0.1 to 10 μm. When the above-mentioned active energy ray-curable adhesive is used for the formation of multiple layers, the thickness of each layer and the type of the adhesive used may be the same or different.

The aforementioned adhesives can be classified into acrylic adhesives, urethane-based adhesives, rubber-based adhesives, silicone-based adhesives, and the like according to the main ingredient polymer, and any of them can be used. . In the adhesive, in addition to the main polymer, crosslinking agents, silane-based compounds, ionic compounds, crosslinking catalysts, antioxidants, tackifiers, plasticizers, dyes, pigments, inorganic fillers, etc. . An adhesive layer can be formed by dissolving and dispersing each component constituting the adhesive in a solvent to obtain an adhesive composition, applying the adhesive composition on a substrate, and then drying it. (adhesive layer). The adhesive layer may be directly formed, or an adhesive layer formed separately on the substrate may be transferred. In order to cover the adhesive surface before bonding, it is also preferable to use a release film. The thickness of the adhesive layer in the case of using the above-mentioned adhesive may be 1 to 500 μm, preferably 2 to 300 μm. When the aforementioned adhesive is used for the formation of multiple layers, the thickness of each layer and the type of adhesive used may be the same or different.

[shading pattern]

The aforementioned light-shielding pattern may be applied as at least a part of a bezel or a housing of the aforementioned flexible display device. The wiring arranged at the edge of the flexible display device is hidden by the light-shielding pattern so as to be difficult to be observed, thereby improving the visibility of the image. The aforementioned light shielding pattern may be in the form of a single layer or a multilayer. The color of the light-shielding pattern is not particularly limited, and may have various colors such as black, white, and metallic. The light-shielding pattern can be formed of a pigment for expressing color, and a polymer such as acrylic resin, ester resin, epoxy resin, polyurethane, and polysiloxane. These may be used individually, or may be used as a mixture of 2 or more types. The aforementioned light-shielding pattern can be formed by various methods such as printing, photolithography, and inkjet. The thickness of the light-shielding pattern is usually 1 to 100 μm, preferably 2 to 50 μm. In addition, it is also preferable to provide a shape such as an inclination in the thickness direction of the light-shielding pattern.

[Example]

Hereinafter, the present invention will be described in further detail by way of examples. Unless otherwise stated, "%" and "part" in an example mean mass % and mass part. First, the evaluation method will be described.

<Measurement of elastic modulus>

The elastic modulus of the polyamideimide films obtained in Examples and Comparative Examples was measured using "AUTOGRAPH AG-IS" manufactured by Shimadzu Corporation. A film with a width of 10 mm was produced, and a stress-strain curve was measured under the conditions of a distance between the clips of 50 mm and a tensile speed of 10 mm/min, and the elastic modulus was calculated from the slope.

<Measurement of total light transmittance>

According to JIS K 7105:1981, the total light transmittance ( Tt).

<Measurement of weight average molecular weight (Mw)>

Gel permeation chromatography (GPC) assay

(1) Pretreatment method

A DMF eluent (10 mmol/L lithium bromide solution) was added to the sample so as to have a concentration of 2 mg/mL, heated at 80° C. with stirring for 30 minutes, and after cooling, filtered through a 0.45 μm membrane filter, and the obtained filtrate was used as Assay solution.

(2) Measurement conditions

Column: TSKgel α-2500 ((7) 7.8 mm diameter × 300 mm) × 1, α-M ((13) 7.8 mm diameter × 300 mm) × 2, manufactured by Tosoh Corporation

Eluent: DMF (added with 10 mmol/L lithium bromide)

Flow: 1.0mL/min

Detector: RI detector

Column temperature: 40℃

Injection volume: 100μL

Molecular weight standard: standard polystyrene

<Measurement of thickness>

The thickness of the polyamide-imide film obtained in the Example and the comparative example was measured using a micrometer ("ID-C112XBS" by Mitutoyo Corporation).

<Varnish stability test>

The concentration was adjusted so that the viscosity was 30,000 to 40,000 cP, the polyamideimide resin and dimethylacetamide were mixed, and the mixture was heated at 70° C. to prepare a varnish. 10 g of the produced varnishes were put into a glass threaded pipe having a diameter of 27 mm, and were allowed to stand at 25° C. for 3 days in an upright state. Then, the glass threaded tube was placed horizontally at 90°, and was further left to stand for 1 hour. After 1 hour, when the liquid level was in a horizontal state, it was determined as a solution state, and when it was not in a horizontal state, it was determined as a gel state. In addition, in the results described in Table 1, the case judged to be in a solution state was denoted by 0, and the case determined to be in a gel state was denoted by x.

<Example 1>

[Preparation of polyamideimide resin (1)]

Under a nitrogen atmosphere, 2,2'-bis(trifluoromethyl)benzidine (TFMB) and N,N-dimethylacetamide (DMAc) were added to a separable flask equipped with a stirring blade to make the TFMB The solid content was 5.39% by mass, and 4,4'-(hexafluoropropylidene)diphenylamine (6FDAM) was added to make it 11.11 mol% with respect to TFMB, and TFMB and 6FDAM were dissolved while stirring at room temperature. in DMAc. Next, 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added to the flask so as to be 44.67 mol% with respect to TFMB, and the mixture was stirred at room temperature for 3 hours. Then, after cooling to 10 degreeC, terephthaloyl chloride (TPC) was added so that it might become 60.30 mol% with respect to TFMB, and it stirred for 30 minutes. Then, the same amount of DMAc as the first added DMAc was added and stirred for 10 minutes. Then, TPC was added so as to be 6.70 mol % with respect to TFMB, followed by stirring for 2 hours. Next, 60.30 mol % of diisopropylethylamine and 4-picoline with respect to TFMB, and 313.67 mol % of acetic anhydride with respect to TFMB were added to the flask, respectively, followed by stirring for 30 minutes. Then, the internal temperature was raised to 70° C., and stirring was further performed for 3 hours to obtain a reaction liquid.

The obtained reaction liquid was cooled to room temperature, put into a large amount of methanol in a linear form, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Next, the reduced-pressure drying of the deposit was performed at 60 degreeC, and the polyamideimide resin (1) was obtained.

[Manufacture of polyamideimide film (1)]

To the obtained polyamideimide resin (1), DMAc was added so that the density|concentration might become 6.5 mass %, the polyamideimide varnish (1) was produced, and it was left to stand at 25 degreeC for 3 days. Then, using an applicator, the obtained polyamideimide varnish (1) was applied to a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film would be 45 μm. The smooth surface of the film was dried at 50°C for 30 minutes, followed by drying at 140°C for 15 minutes to obtain a self-supporting film. The self-supporting film was fixed to a metal frame, and was further dried at 200° C. for 60 minutes to obtain a polyamideimide film (1) having a thickness of 40 μm.

<Example 2>

[Preparation of polyamideimide resin (2)]

In a nitrogen atmosphere, TFMB and DMAc were added to a separable flask equipped with a stirring blade so that the solid content of TFMB was 4.81% by mass, and 6FDAM was further added so as to be 25.00 mol% relative to TFMB. TFMB and 6FDAM were dissolved in DMAc with stirring. Next, BPDA was added to the flask so as to be 50.25 mol% with respect to TFMB, and the mixture was stirred at room temperature for 3 hours. Then, after cooling to 10 degreeC, TPC was added so that it might become 67.84 mol% with respect to TFMB, and it stirred for 30 minutes. Then, the same amount of DMAc as the first added DMAc was added and stirred for 10 minutes. Then, TPC was added so as to be 7.54 mol % with respect to TFMB, followed by stirring for 2 hours. Next, 75.38 mol % of diisopropylethylamine and 4-picoline with respect to TFMB, and 351.76 mol % of acetic anhydride with respect to TFMB were added to the flask, respectively, followed by stirring for 30 minutes. Then, the internal temperature was raised to 70° C., and stirring was further performed for 3 hours to obtain a reaction liquid.

The obtained reaction liquid was cooled to room temperature, put into a large amount of methanol in a linear form, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Next, the reduced-pressure drying of the deposit was performed at 60 degreeC, and the polyamideimide resin (2) was obtained.

[Manufacture of polyamideimide film (2)]

To the obtained polyamideimide resin (2), DMAc was added so that the density|concentration might become 6.0 mass %, the polyamideimide varnish (2) was produced, and it was left to stand at 25 degreeC for 3 days. Then, using an applicator, the obtained polyamide-imide varnish (2) was applied to a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film would be 45 μm. The smooth surface of the film was dried at 50°C for 30 minutes, followed by drying at 140°C for 15 minutes to obtain a self-supporting film. The self-supporting film was fixed to the metal frame, and was further dried at 200° C. for 60 minutes to obtain a polyamideimide film (2) having a thickness of 40 μm.

<Example 3>

[Preparation of polyamideimide resin (3)]

In a nitrogen atmosphere, TFMB and DMAc were added to a separable flask equipped with a stirring blade so that the solid content of TFMB was 5.44 mass %, and 6FDAM was further added so as to be 11.11 mol % with respect to TFMB, at room temperature. TFMB and 6FDAM were dissolved in DMAc with stirring. Next, BPDA was added to the flask so as to be 34.01 mol % with respect to TFMB, and the mixture was stirred at room temperature for 3 hours. Then, after cooling to 10 degreeC, TPC was added so that it might become 71.43 mol% with respect to TFMB, and it stirred for 30 minutes. Then, the same amount of DMAc as the first added DMAc was added, followed by stirring for 10 minutes. Then, TPC was added so as to be 7.94 mol % relative to TFMB, and stirring was performed for 2 hours. Next, 79.37 mol % of diisopropylethylamine and 4-picoline with respect to TFMB, and 238.10 mol % of acetic anhydride with respect to TFMB were added to the flask, respectively, followed by stirring for 30 minutes. Then, the internal temperature was raised to 70° C., and stirring was further performed for 3 hours to obtain a reaction liquid.

The obtained reaction liquid was cooled to room temperature, put into a large amount of methanol in a linear form, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Next, the reduced-pressure drying of the deposit was performed at 60 degreeC, and the polyamideimide resin (3) was obtained.

[Manufacture of polyamideimide film (3)]

To the obtained polyamideimide resin (3), DMAc was added so that the density|concentration might become 8.0 mass %, the polyamideimide varnish (3) was produced, and it was left to stand at 25 degreeC for 3 days. Then, using an applicator, the obtained polyamideimide varnish (3) was applied to a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film would be 55 μm. The smooth surface of the film was dried at 50°C for 30 minutes, followed by drying at 140°C for 15 minutes to obtain a self-supporting film. The self-supporting film was fixed to the metal frame, and was further dried at 200° C. for 60 minutes to obtain a polyamideimide film (3) having a thickness of 50 μm.

<Example 4>

[Preparation of polyamideimide resin (4)]

In a nitrogen atmosphere, TFMB and DMAc were added to a separable flask equipped with a stirring blade so that the solid content of TFMB was 5.39 mass %, and 6FDAM was further added to make it 11.11 mol % with respect to TFMB, at room temperature. TFMB and 6FDAM were dissolved in DMAc with stirring. Next, BPDA was added to the flask so as to be 33.50 mol % with respect to TFMB, and the mixture was stirred at room temperature for 3 hours. Then, after cooling to 10° C., 4,4′ oxybis(benzoyl chloride) (OBBC) was added to make it 11.17 mol % with respect to TFMB, and TPC was added so as to make it become 11.17 mol % with respect to TFMB 60.30 mol%, stirring for 30 minutes. Then, the same amount of DMAc as the first added DMAc was added and stirred for 10 minutes. Then, TPC was added so as to be 6.70 mol % with respect to TFMB, followed by stirring for 2 hours. Next, 78.17 mol % of diisopropylethylamine and 4-picoline with respect to TFMB, and 234.51 mol % of acetic anhydride with respect to TFMB were added to the flask, respectively, followed by stirring for 30 minutes. Then, the internal temperature was raised to 70° C., and stirring was further performed for 3 hours to obtain a reaction liquid.

The obtained reaction liquid was cooled to room temperature, put into a large amount of methanol in a linear form, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Next, the reduced-pressure drying of the deposit was performed at 60 degreeC, and the polyamideimide resin (4) was obtained.

[Manufacture of polyamideimide film (4)]

To the obtained polyamideimide resin (4), DMAc was added so that the density|concentration might become 6.5 mass %, the polyamideimide varnish (4) was produced, and it was left to stand at 25 degreeC for 3 days. Then, using an applicator, the obtained polyamide-imide varnish (4) was applied to a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film would be 42 μm. The smooth surface of the film was dried at 50°C for 30 minutes, followed by drying at 140°C for 15 minutes to obtain a self-supporting film. The self-supporting film was fixed to the metal frame, and was further dried at 200° C. for 60 minutes to obtain a polyamideimide film (4) having a thickness of 38 μm.

<Comparative Example 1>

[Preparation of polyamideimide resin (5)]

In a nitrogen atmosphere, TFMB and DMAc were added to a separable flask equipped with a stirring blade so that the solid content of TFMB was 5.36 mass %, and 6FDAM was further added to make it 11.11 mol % with respect to TFMB, at room temperature. TFMB and 6FDAM were dissolved in DMAc with stirring. Next, BPDA was added to the flask so as to be 43.35 mol % with respect to TFMB, and the mixture was stirred at room temperature for 3 hours. Then, after cooling to 10 degreeC, TPC was added so that it might become 61.23 mol% with respect to TFMB, and it stirred for 30 minutes. Then, the same amount of DMAc as the first added DMAc was added and stirred for 10 minutes. Then, TPC was added so as to be 6.80 mol % with respect to TFMB, followed by stirring for 2 hours. Next, 68.03 mol % of diisopropylethylamine and 4-picoline with respect to TFMB, and 317.46 mol % of acetic anhydride with respect to TFMB were added to the flask, respectively, followed by stirring for 30 minutes. Then, the internal temperature was raised to 70° C., and stirring was further performed for 3 hours to obtain a reaction liquid.

The obtained reaction liquid was cooled to room temperature, put into a large amount of methanol in a linear form, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Next, the reduced-pressure drying of the deposit was performed at 60 degreeC, and the polyamide-imide resin (5) was obtained.

[Manufacture of polyamideimide film (5)]

To the obtained polyamideimide resin (5), DMAc was added so that the density|concentration might become 9.0 mass %, the polyamideimide varnish (5) was produced, and it was left to stand at 25 degreeC for 3 days. When the stability was confirmed 3 days later, it was in a gel state and fluidity was lost, so that the coating could not be performed and a film could not be obtained.

<Comparative Example 2>

[Preparation of polyamideimide resin (6)]

In a nitrogen atmosphere, TFMB and DMAc were added to a separable flask equipped with a stirring blade so that the solid content of TFMB was 5.31% by mass, and 6FDAM was further added to make it 11.11 mol% with respect to TFMB, at room temperature. TFMB and 6FDAM were dissolved in DMAc with stirring. Next, BPDA was added to the flask so as to be 46.30 mol % with respect to TFMB, and the mixture was stirred at room temperature for 3 hours. Then, after cooling to 10 degreeC, TPC was added so that it might become 62.50 mol% with respect to TFMB, and it stirred for 30 minutes. Then, the same amount of DMAc as the first added DMAc was added and stirred for 10 minutes. Then, TPC was added so as to be 6.94 mol % with respect to TFMB, followed by stirring for 2 hours. Next, 69.44 mol % of diisopropylethylamine and 4-picoline with respect to TFMB, and 324.07 mol % of acetic anhydride with respect to TFMB were added to the flask, respectively, followed by stirring for 30 minutes. Then, the internal temperature was raised to 70° C., and stirring was further performed for 3 hours to obtain a reaction liquid.

The obtained reaction liquid was cooled to room temperature, put into a large amount of methanol in a linear form, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Next, the reduced-pressure drying of the deposit was performed at 60 degreeC, and the polyamideimide resin (6) was obtained.

[Manufacture of polyamideimide film (6)]

To the obtained polyamideimide resin (6), DMAc was added so that the density|concentration might become 8.0 mass %, the polyamideimide varnish (6) was produced, and it was left to stand at 25 degreeC for 3 days. When the stability was confirmed 3 days later, it was in a gel state and fluidity was lost, so that the coating could not be performed and a film could not be obtained.

<Comparative Example 3>

[Preparation of polyamideimide resin (7)]

In a nitrogen atmosphere, TFMB and DMAc were added to a separable flask equipped with a stirring blade so that the solid content of TFMB was 4.89% by mass, and 6FDAM was further added so as to be 11.11 mol% with respect to TFMB, at room temperature. TFMB and 6FDAM were dissolved in DMAc with stirring. Next, 6FDA was added so that it might become 44.67 mol% with respect to TFMB, and it stirred at room temperature for 3 hours. Then, after cooling to 10 degreeC, TPC was added so that it might become 60.30 mol% with respect to TFMB, and it stirred for 30 minutes. Then, the same amount of DMAc as the first added DMAc was added and stirred for 10 minutes. Then, TPC was added so as to be 6.70 mol % with respect to TFMB, followed by stirring for 2 hours. Next, 67.00 mol % of diisopropylethylamine and 4-picoline with respect to TFMB, and 312.67 mol % of acetic anhydride with respect to TFMB were added to the flask, respectively, followed by stirring for 30 minutes. Then, the internal temperature was raised to 70° C., and stirring was further performed for 3 hours to obtain a reaction liquid.

The obtained reaction liquid was cooled to room temperature, put into a large amount of methanol in a linear form, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Next, the reduced-pressure drying of the deposit was performed at 60 degreeC, and the polyamideimide resin (7) was obtained.

[Manufacture of polyamideimide film (7)]

To the obtained polyamideimide resin (7), DMAc was added so that the density|concentration might become 8.0 mass %, the polyamideimide varnish (7) was produced, and it was left to stand at 25 degreeC for 3 days. Then, using an applicator, the obtained polyamideimide varnish (7) was applied to a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film would be 55 μm. The smooth surface of the film was dried at 50°C for 30 minutes, followed by drying at 140°C for 15 minutes to obtain a self-supporting film. The self-supporting film was fixed to the metal frame, and was further dried at 200° C. for 60 minutes to obtain a polyamideimide film (7) having a thickness of 50 μm.

<Example 5>

[Preparation of polyamideimide resin (8)]

In a nitrogen atmosphere, TFMB and DMAc were added to a separable flask equipped with a stirring blade so that the solid content of TFMB was 4.65 mass %, and 6FDAM was further added to make it 25.00 mol % with respect to TFMB, at room temperature. TFMB and 6FDAM were dissolved in DMAc with stirring. Next, BPDA was added to the flask so as to be 75.76 mol % with respect to TFMB, and the mixture was stirred at room temperature for 3 hours. Then, after cooling to 10 degreeC, TPC was added so that it might become 45.46 mol% with respect to TFMB, and it stirred for 30 minutes. Then, the same amount of DMAc as the first added DMAc was added and stirred for 10 minutes. Then, TPC was added so as to be 5.05 mol % with respect to TFMB, followed by stirring for 2 hours. Next, 50.51 mol % of diisopropylethylamine and 4-picoline with respect to TFMB, and 530.30 mol % of acetic anhydride with respect to TFMB were added to the flask, respectively, followed by stirring for 30 minutes. Then, the internal temperature was raised to 70° C., and stirring was further performed for 3 hours to obtain a reaction liquid.

The obtained reaction liquid was cooled to room temperature, put into a large amount of methanol in a linear form, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Next, the reduced-pressure drying of the deposit was performed at 60 degreeC, and the polyamideimide resin (8) was obtained.

[Manufacture of polyamideimide film (8)]

To the obtained polyamideimide resin (8), DMAc was added so that the density|concentration might become 6.5 mass %, the polyamideimide varnish (8) was produced, and it was left to stand at 25 degreeC for 3 days. Then, using an applicator, the obtained polyamideimide varnish (8) was applied to a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film would be 55 μm. The smooth surface of the film was dried at 50°C for 30 minutes, followed by drying at 140°C for 15 minutes to obtain a self-supporting film. The self-supporting film was fixed to the metal frame, and was further dried at 200° C. for 60 minutes to obtain a polyamideimide film (8) having a thickness of 50 μm.

<Example 6>

[Preparation of polyamideimide resin (9)]

In a nitrogen atmosphere, TFMB and DMAc were added to a separable flask equipped with a stirring blade so that the solid content of TFMB was 5.35 mass %, and 6FDAM was further added to make it 11.11 mol % with respect to TFMB, at room temperature. TFMB and 6FDAM were dissolved in DMAc with stirring. Next, BPDA was added to the flask so as to be 34.01 mol % with respect to TFMB, and the mixture was stirred at room temperature for 3 hours. Then, after cooling to 10 degreeC, OBBC was added so that it might become 11.34 mol% with respect to TFMB, TPC was added so that it might become 61.23 mol% with respect to TFMB, and it stirred for 30 minutes. Then, the same amount of DMAc as the first added DMAc was added and stirred for 10 minutes. Then, TPC was added so as to be 6.80 mol % with respect to TFMB, followed by stirring for 2 hours. Next, 79.37 mol % of diisopropylethylamine and 4-picoline with respect to TFMB, and 238.10 mol % of acetic anhydride with respect to TFMB were added to the flask, respectively, followed by stirring for 30 minutes. Then, the internal temperature was raised to 70° C., and stirring was further performed for 3 hours to obtain a reaction liquid.

The obtained reaction liquid was cooled to room temperature, put into a large amount of methanol in a linear form, and the deposited precipitate was taken out, immersed in methanol for 6 hours, and washed with methanol. Next, the reduced-pressure drying of the deposit was performed at 60 degreeC, and the polyamideimide resin (9) was obtained.

[Manufacture of polyamideimide film (9)]

To the obtained polyamideimide resin (9), DMAc was added so that the density|concentration might become 9.0 mass %, the polyamideimide varnish (9) was produced, and it was left to stand at 25 degreeC for 3 days. Then, using an applicator, the obtained polyamideimide varnish (9) was applied to a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film would be 55 μm. The smooth surface of the film was dried at 50°C for 30 minutes, followed by drying at 140°C for 15 minutes to obtain a self-supporting film. The self-supporting film was fixed to the metal frame, and was further dried at 200° C. for 60 minutes to obtain a polyamideimide film (9) having a thickness of 50 μm.

The weight average molecular weights of the polyamideimide resins obtained in the Examples and Comparative Examples and the elasticity of the polyamideimide-based resin films (1) to (4) and (8) to (9) were measured in accordance with the above-mentioned methods. Modulus, total light transmittance and varnish stability. The obtained results are shown in Table 1.

[Table 1]

As shown in Table 1, the films containing the polyamideimide resins of Examples 1 to 6 were films having a high elastic modulus while maintaining a high total light transmittance. In addition, the stability of the varnish is also good. On the other hand, the film containing the polyamide-imide resin of Comparative Examples 1 and 2 having a low weight average molecular weight of the resin had poor stability of the varnish and could not be formed into a film. In addition, the film containing the polyamideimide resin of Comparative Example 3 which does not contain the structural unit (a1) in which Y in the formula (a) is represented by the formula (1) does not have a sufficient elastic modulus.

Claims (12)

1. A polyamideimide resin comprising at least a structural unit represented by the formula (a) derived from a tetracarboxylic acid compound, a structural unit represented by the formula (b) derived from a dicarboxylic acid compound, and a structural unit represented by the formula (c) derived from a diamine compound, wherein,

comprising a structural unit (a1) wherein Y in the formula (a) is represented by the formula (1) as the structural unit derived from a tetracarboxylic acid compound,

the polyamide-imide resin has a weight average molecular weight of 330,000 or more in terms of polystyrene,

in the formula (a), Y represents a tetravalent organic group,

in the formula (b), Z represents a divalent organic group,

in the formula (c), X represents a divalent organic group,

R^cindependently of one another, represents a hydrogen atom or a chemical bond,

in the formula (1), R^aIndependently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms,

R^athe hydrogen atoms contained in (a) may be substituted independently of each other by halogen atoms,

n represents an integer of 0 to 2,

denotes a bond.

2. The polyamideimide-based resin according to claim 1, wherein the structural unit (b1) represented by the formula (2) is contained as a structural unit derived from a dicarboxylic acid compound, and,

comprising the structural unit (c1) represented by the formula (3) as a structural unit derived from a diamine compound,

in the formula (2), Z¹Represents a divalent aromatic group which may have a substituent,

the symbol represents a chemical bond,

in the formula (3), X¹Represents a divalent aromatic group which may have a substituent,

R^cindependently of one another, represent a hydrogen atom or a chemical bond,

denotes a bond.

3. The polyamideimide-based resin according to claim 2, wherein X in the formula (3)¹Is represented by the formula (4),

in the formula (4), R^bIndependently represents an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms or an alkoxy group having 1 to 6 carbon atoms,

R^bthe hydrogen atoms contained in (a) may be substituted independently of each other by halogen atoms,

r independently represents an integer of 1 to 4,

denotes a bond.

4. The polyamideimide-based resin according to any one of claims 1 to 3, wherein a structural unit (b2) wherein Z in the formula (b) is represented by the formula (5) is contained as a structural unit derived from a dicarboxylic acid compound, and/or,

comprising a structural unit (c2) wherein X in the formula (c) is represented by the formula (5) as a structural unit derived from a diamine compound, and/or,

further comprising a structural unit (a2) wherein Y in the formula (a) is represented by the formula (6) as a structural unit derived from a tetracarboxylic acid compound,

in the formula (5), Ar¹Independently of each other, a divalent aromatic group which may have a substituent,

v represents-O-, diphenylmethylene, straight-chain, branched or alicyclic divalent hydrocarbon group having 1 to 12 carbon atoms, -SO₂-, -S-, -CO-or-N (R)¹²) -, where the hydrogen atoms contained in the hydrocarbon group may be substituted independently of each other by halogen atoms, R¹²Represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom,

m represents an integer of 1 to 3, wherein when m is 2 or 3, a plurality of V may be the same or different,

the symbol represents a chemical bond,

in the formula (6), Ar²Independently of each other, a trivalent aromatic group which may have a substituent,

s represents an integer of 0 to 2,

Ar¹v and Ar as for formula (5)¹V and are as defined above, wherein when s is 2, there are a plurality of V and Ar¹Each of which may be the same or different from each other.

5. The polyamideimide-based resin according to claim 4, wherein the formula (5) and the formula (6) are represented by the formula (7),

in the formula (7), R¹Independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms,An alkoxy group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms,

R¹the hydrogen atoms contained in (a) may be substituted independently of each other by halogen atoms,

R^*represents R¹Or a chemical bond to the substrate,

the symbol represents a chemical bond,

v represents-O-, diphenylmethylene, straight-chain, branched or alicyclic divalent hydrocarbon group having 1 to 12 carbon atoms, -SO₂-, -S-, -CO-or-N (R)¹²) Here, the hydrogen atoms contained in the hydrocarbon group may be substituted with halogen atoms independently of each other,

R¹²represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom.

6. The polyamideimide-based resin according to claim 5, wherein the formula (7) is represented by formula (7 ') or formula (7'),

in the formula (7'), R^*Represents a hydrogen atom or a chemical bond, represents a chemical bond,

in formula (7 ″), denotes a bond.

7. The polyamideimide-based resin according to any one of claims 1 to 6, wherein the formula (1) is represented by the formula (1'),

denotes a bond.

8. A polyamide imide resin varnish comprising the polyamide imide resin according to any one of claims 1 to 7 and a solvent.

9. An optical film comprising the polyamideimide-based resin according to any one of claims 1 to 7.

10. A flexible display device provided with the optical film according to claim 9.

11. The flexible display device of claim 10, further provided with a touch sensor.

12. The flexible display device according to claim 10 or 11, further comprising a polarizing plate.