CN113227211A - Polyamide resin, optical film, and flexible display device - Google Patents

Abstract

The present invention provides optical films with high elastic modulus and low humidity expansion coefficient. An optical film comprising a polyamide-based resin having a weight average molecular weight of 200,000 to 1,000,000, the polyamide-based resin having at least a structural unit represented by formula (1) and a structural unit represented by formula (3). In formula (1), Ar ¹ represents a divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms, and X ¹ represents a divalent organic group. In formula (3), Z ¹ represents Ar ¹ , or a divalent organic group other than Ar ¹ , Ar ¹ is the same as the definition in the aforementioned formula (1), X ² represents a divalent organic group, wherein, in Z When ¹ represents Ar ¹ , X ^{1 in the formula (1) and X 2 in} the formula (3) are different from each other.

Description

Polyamide resin, optical film and flexible display device

technical field

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

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 polyamide-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

However, when an optical film using a polyamide-based resin is used in a flexible display device or the like, defects such as damage and wrinkles may occur in the optical film due to bending or contact with external factors. The inventors of the present application have conducted various studies on means for improving the above-mentioned situation, and found that defects such as damage are less likely to occur on the optical film by increasing the elastic modulus of the optical film. In addition, a flexible display device is used in various environments for a long time, and in particular, an optical film to which a load is applied due to changes in temperature, humidity, and the like may expand or contract in the plane direction. Therefore, the optical film is also required to have a low coefficient of humidity expansion with respect to changes in temperature and humidity.

Therefore, the subject of this invention is to provide the optical film which has a high elastic modulus and a low humidity expansion coefficient.

means of solving problems

In order to solve the above-mentioned problems, the inventors of the present application have conducted intensive studies focusing on the structure of the monomer constituting the polyamide-based resin contained in the optical film. As a result, the present inventors have found that an optical film including a polyamide-based resin having at least a specific structural unit and having a weight average molecular weight in a specific range has both a high elastic modulus and a low humidity expansion coefficient, and completed the present invention.

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

[1] An optical film comprising a polyamide-based resin having a weight average molecular weight of 200,000 to 1,000,000, the polyamide-based resin having at least a structural unit represented by formula (1) and a structural unit represented by formula (3).

[Chemical formula 1]

[In formula (1), Ar ¹ represents a divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms, and X ¹ represents a divalent organic group]

[Chemical formula 2]

[In formula (3),

Z ¹ represents Ar ¹ , or represents a divalent organic group other than Ar ¹ , and Ar ¹ has the same definition as in the aforementioned formula (1),

X ² represents a divalent organic group, and when Z ¹ represents Ar ¹ , X ^{1 in the formula (1) and X 2 in} the formula (3) are different from each other]

[2] The optical film according to the above [1], wherein the fluoroalkyl group having 1 to 12 carbon atoms in Ar ¹ in the formula (1) is a perfluoroalkyl group having 1 to 12 carbon atoms .

[3] The optical film according to the above [1] or [2], wherein the structural unit represented by the formula (1) contains the aromatic group represented by the formula (4) as Ar ¹ .

[Chemical formula 3]

[In formula (4),

R ¹ represents a fluoroalkyl group having 1 to 12 carbon atoms,

n and k independently represent an integer of 1 to 4, wherein, when n and/or k represent an integer of 2 to 4, a plurality of R ¹ may be the same or different from each other,

＊Indicates chemical bond]

[4] The optical film according to the above [3], wherein the two chemical bonds in the formula (4) are located in para positions with each other.

[5] The optical film according to the above [3] or [4], wherein k in the formula (4) is 1 or 2.

[6] The optical film according to any one of the above [3] to [5], wherein R ¹ in the formula (4) represents a perfluoroalkyl group having 1 to 12 carbon atoms, and n is 1 or 2.

[7] The optical film according to any one of the above [1] to [6], wherein the structural unit represented by the formula (1) and the structural unit represented by the formula (3) each include 2 represented by the formula (5) valent organic groups as X ¹ and X ² .

[Chemical formula 4]

[In formula (5),

Ar ² represents a divalent aromatic group which may have a substituent,

V represents a single bond, -O-, diphenylmethylene, fluorenyl, linear, branched or alicyclic divalent hydrocarbon group having 1 to 12 carbon atoms, -SO ₂ -, -S -, -CO-, -PO-, -PO ₂ -, -N(R ^a )- or -Si(R ^b ) ₂ -, wherein the hydrogen atoms contained in the hydrocarbon group independently of each other may be substituted by halogen atoms, R ^a and R ^b independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may be substituted by a halogen atom,

m represents an integer from 0 to 3,

＊Indicates chemical bond]

[8] The optical film according to the above [7], wherein m in the formula (5) is 1.

[9] The optical film according to the above [7] or [8], wherein the formula (5) is represented by the formula (5a).

[Chemical formula 5]

[In formula (5),

R ² represents a fluoroalkyl group having 1 to 12 carbon atoms,

p and q independently represent an integer of 1 to 4, and when p and/or q represent an integer of 2 to 4, a plurality of R ² may be the same or different from each other,

＊Indicates chemical bond]

[10] The optical film according to the above [9], wherein the formula (5a) is represented by the formula (5c).

[Chemical formula 6]

[* in formula (5c) represents a chemical bond]

[11] The optical film according to any one of the above [1] to [10], which has a thickness of 10 to 200 μm.

[12] A flexible display device including the optical film according to any one of the above [1] to [11].

[13] The flexible display device according to the above [12], further including a touch sensor.

[14] The flexible display device according to the above [12] or [13], further comprising a polarizing plate.

[15] A polyamide-based resin having a weight average molecular weight of 200,000 to 1,000,000, the polyamide-based resin having at least the aromatic group represented by the formula (1) and containing the aromatic group represented by the formula (4) as the formula (1) The structural unit of Ar ¹ in , and the structural unit represented by formula (3).

[Chemical formula 7]

[In formula (1),

Ar ¹ represents a divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms,

X ¹ represents a divalent organic group]

[Chemical formula 8]

[In formula (4), R ¹ represents a fluoroalkyl group having 1 to 12 carbon atoms,

n and k independently represent an integer of 1 to 4, wherein, when n and/or k represent an integer of 2 to 4, a plurality of R ¹ may be the same or different from each other,

*Indicates chemical bond]

[Chemical formula 9]

[In formula (3), Z ¹ represents Ar ¹ , or represents a divalent organic group other than Ar ¹ , and Ar ¹ has the same definition as in the aforementioned formula (1),

X ² represents a divalent organic group, and when Z ¹ represents Ar ¹ , X ^{1 in the formula (1) and X 2 in} the formula (3) are different from each other]

effect of invention

The optical film of the present invention has a high elastic modulus and a low humidity expansion coefficient.

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 optical film of the present invention contains a polyamide-based resin having a weight average molecular weight of 200,000 to 1,000,000, the polyamide-based resin having at least a structural unit represented by formula (1) and a structural unit represented by formula (3).

[Chemical formula 10]

[In formula (1), Ar ¹ represents a divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms, and X ¹ represents a divalent organic group]

[Chemical formula 11]

[In formula (3), Z ¹ represents Ar ¹ , or represents a divalent organic group other than Ar ¹ , and Ar ¹ has the same definition as in the aforementioned formula (1),

X ² represents a divalent organic group, and when Z ¹ represents Ar ¹ , X ^{1 in the formula (1) and X 2 in} the formula (3) are different from each other]

In addition, in Formula (1) and Formula (3), the bond shown by a dotted line shows the chemical bond which couple|bonded with the adjacent structural unit. In this specification, the bonds shown by the dotted lines in other chemical structural formulae similarly represent chemical bonds bonded to adjacent structural units or groups.

The polyamide-based resin contained in the optical film of the present invention may have one type of structural unit represented by formula (1), or may have two or more types of structural units represented by formula (1). Similarly, the polyamide-based resin may have one type of structural unit represented by formula (3), or may have two or more types of structural units represented by formula (3). The structural unit represented by formula (1) and the structural unit represented by formula (3) are structural units formed by reacting a dicarboxylic acid compound and a diamine compound. In this specification, the structural unit represented by formula (1) is also referred to as "structural unit (1)", and the structural unit represented by formula (3) is also referred to as "structural unit (3)". In addition, when the polyamide-based resin contained in the optical film of the present invention has two or more structural units represented by the formula (1), at least one structural unit in the structural unit may be the formula (1) The represented structural unit, so that the other at least one structural unit is the structural unit represented by the formula (3).

The polyamide-based resin has the structural unit represented by the above-mentioned formula (1) and the structural unit represented by the formula (3), which means that in the polyamide-based resin,

(a) having at least the structural unit represented by the formula (1) and the structural unit represented by the formula (3) where Z ¹ represents a divalent organic group not belonging to Ar ¹ , in this case, X ¹ in the formula (1) X ² in formula (3) may be the same or different from each other; or,

(b) having at least the structural unit represented by the formula (1) and the structural unit represented by the formula (3) in which Z ¹ belongs to Ar ¹ , in this case, X ¹ in the formula (1) and X in the formula (3) ² are different from each other.

In the case of the above (a), the structural unit represented by the formula (3) is represented by the formula (3a), and in the case of the above (b), the structural unit represented by the formula (3) is represented by the formula (3b). In this specification, the structural unit represented by formula (3a) is also referred to as "structural unit (3a)", and the structural unit represented by formula (3b) is also referred to as "structural unit (3b)".

[Chemical formula 12]

[In formula (3a), Z ² represents a divalent organic group that is not a divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms,

X ³ represents a divalent organic group]

[Chemical formula 13]

[In formula (3a), Ar ³ represents a divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms,

X ⁴ represents a divalent organic group different from X ¹ in the formula (1)]

In the optical film of the present invention comprising the above-described polyamide-based resin having the structural unit (1) and the structural unit (3) and having a weight average molecular weight of 200,000 to 1,000,000, the elastic modulus is improved and the coefficient of humidity expansion can be reduced. Although the reason is not clear, it is considered as follows: Ar ¹ in the above-mentioned formula (1) is a fluoroalkyl group having 1 to 12 carbon atoms in the skeleton of the polyamide-based resin having a predetermined weight average molecular weight. As a bivalent aromatic group, a specific part in the skeleton of the polyamide-based resin has moderate rigidity. In addition, it is considered that the polyamide-based resin further has a structural unit (3a) and/or a structural unit (3b), thereby having an intermolecular repulsion force. As a result, it is thought that the improvement of the elastic modulus of the optical film containing the said polyamide-type resin and the fall of the humidity expansion coefficient can be achieved surprisingly. The coefficient of humidity expansion is an index indicating the degree of expansion and contraction in the plane direction of the optical film under a load, and it has been confirmed that the coefficient of humidity expansion has a large influence on the molecular structure of the polyamide-based resin constituting the optical film. Furthermore, it was confirmed that it may be difficult to achieve both a high elastic modulus and a low humidity expansion coefficient of an optical film by simply increasing the structure having a halogen atom. In the present invention, it was found that by including at least a structural unit (1) (which includes a divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms) and a structural unit (3), and having a weight in a predetermined range An optical film of a polyamide-based resin having an average molecular weight can obtain an optical film having both a high elastic modulus and a low humidity expansion coefficient.

The polyamide-type resin contained in the optical film of this invention has a structural unit (1) and a structural unit (3). From the viewpoint of easily increasing the elastic modulus of the optical film and easily reducing the humidity expansion coefficient, when the total of the structural unit (1) and the structural unit (3) contained in the polyamide-based resin is taken as 100 mol %, the structural unit ( The ratio of 1) is preferably 10 to 99 mol%, more preferably 20 to 95 mol%, still more preferably 30 to 90 mol%, and particularly preferably 40 to 85 mol%. When the ratio of a structural unit (1) is more than the said lower limit, the elastic modulus of an optical film becomes easy to improve, and it becomes easy to reduce a humidity expansion coefficient. Moreover, when the ratio of a structural unit (1) is below the said upper limit, it becomes easy to ensure the solubility to a solvent. In addition, content of a structural unit (1) and a structural unit (3) can be measured using ¹ H-NMR, for example, or can also be calculated from the input ratio of a raw material.

In one preferred embodiment of the present invention in which the polyamide-based resin contained in the optical film of the present invention has a structural unit (1) and a structural unit (3a), from the viewpoints of easily improving the elastic modulus of the optical film and easily reducing the coefficient of humidity expansion When the total of the structural unit (1) and the structural unit (3a) contained in the polyamide-based resin is taken as 100 mol %, the ratio of the structural unit (1) is preferably 10 to 99 mol %, and more preferably 20 to 99 mol %. 95 mol%, more preferably 30 to 90 mol%, particularly preferably 40 to 85 mol%. When the ratio of a structural unit (1) is more than the said lower limit, the elastic modulus of an optical film becomes easy to improve, and it becomes easy to reduce a humidity expansion coefficient. Moreover, when the ratio of a structural unit (1) is below the said upper limit, it becomes easy to ensure the solubility to a solvent.

In a preferred embodiment of the present invention in which the polyamide-based resin contained in the optical film of the present invention has a structural unit (1) and a structural unit (3b), from the viewpoints of easy improvement in the elastic modulus of the optical film and easy reduction in the humidity expansion coefficient When the total of the structural unit (1) and the structural unit (3b) contained in the polyamide-based resin is taken as 100 mol %, the ratio of the structural unit (1) is preferably 10 to 99 mol %, and more preferably 20 to 99 mol %. 95 mol%, more preferably 30 to 90 mol%, particularly preferably 40 to 85 mol%. When the ratio of a structural unit (1) is more than the said lower limit, the elastic modulus of an optical film becomes easy to improve, and it becomes easy to reduce a humidity expansion coefficient. Moreover, when the ratio of a structural unit (1) is below the said upper limit, it becomes easy to ensure the solubility to a solvent. In addition, content of a structural unit (3a) and a structural unit (3b) can also be measured using ¹ H-NMR, for example, or can also be calculated from the input ratio of a raw material.

Ar ¹ in formula (1) represents a divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms. It should be noted that the so-called divalent aromatic group in this specification refers to 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. group. The divalent aromatic group may contain an aromatic ring formed of a ring (single ring, fused polycyclic ring, or ring group) only by carbon atoms, or may contain an aromatic ring formed by containing atoms other than carbon atoms. 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 to 18, more preferably 5 to 14, and even more preferably 5 to 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, benzimidazole, benzoxazole, and the like.

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.

The divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms is preferably fluorine having 1 to 12 carbon atoms, from the viewpoints that the elastic modulus of the optical film can be easily increased and the humidity expansion coefficient can be easily lowered. A group in which two hydrogen atoms of an aromatic hydrocarbon ring of an alkyl group are replaced by chemical bonds, more preferably 2 groups of benzene, biphenyl, terphenyl or tetraphenyl having a fluoroalkyl group having 1 to 12 carbon atoms. A group in which one hydrogen atom is replaced by a chemical bond is more preferably a group in which two hydrogen atoms of a benzene or biphenyl having a fluoroalkyl group having 1 to 12 carbon atoms are replaced by a chemical bond.

The fluoroalkyl group having 1 to 12 carbon atoms in Ar ¹ in the formula (1) is a linear or branched alkyl group having 1 to 12 carbon atoms where at least one hydrogen atom is substituted with a fluorine atom formed group. Examples of linear or branched fluoroalkyl groups having 1 to 12 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, and tert-butyl. , n-pentyl, 2-methyl-butyl, 3-methylbutyl, 2-ethyl-propyl, n-hexyl, n-heptyl, n-octyl, tert-octyl, n-nonyl and n-decyl A group in which at least one hydrogen atom is substituted by a fluorine atom. Specific examples of the fluoroalkyl group having 1 to 12 carbon atoms include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a difluoroethyl group, a trifluoroethyl group, and a pentafluoroethyl group. Fluoroethyl, heptafluoropropyl, nonafluorobutyl, etc. The number of carbon atoms in the fluoroalkyl group is preferably 1 to 6, more preferably 1 to 4, and still more preferably 1 or 2.

The fluoroalkyl group having 1 to 12 carbon atoms is preferably a perfluoroalkyl group having 1 to 12 carbon atoms, and more preferably a carbon atom, from the viewpoints that the elastic modulus of the optical film can be easily increased and the humidity expansion coefficient can be easily lowered. The perfluoroalkyl group having 1 to 6 numbers is more preferably a perfluoroalkyl group having 1 to 4 carbon atoms, and particularly preferably a trifluoromethyl group or a pentafluoroethyl group.

Ar ¹ in the formula (1) may have at least one fluoroalkyl group having 1 to 12 carbon atoms, and the number is not particularly limited, but from the viewpoints of easily increasing the elastic modulus of the optical film and easily reducing the humidity expansion coefficient It is considered that the number of fluoroalkyl groups having 1 to 12 carbon atoms in Ar ¹ is preferably 1 to 6, and more preferably 1 to 4. When Ar ¹ in formula (1) has two or more fluoroalkyl groups having 1 to 12 carbon atoms, these may be the same or different from each other.

Ar ¹ in the formula (1) may have other substituents in addition to the fluoroalkyl group having 1 to 12 carbon atoms. Examples of other substituents include an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms.

In a preferred embodiment of the present invention, the structural unit represented by the formula (1) contains a divalent aromatic group represented by the formula (4) as Ar from the viewpoints that the elastic modulus of the optical film is easily increased and the humidity expansion coefficient is easily lowered ¹ .

[Chemical formula 14]

[In formula (4),

R ¹ independently represents a fluoroalkyl group having 1 to 12 carbon atoms,

n and k independently represent an integer of 1 to 4, wherein, when n and/or k represent an integer of 2 to 4, a plurality of R ¹ may be the same or different from each other,

＊Indicates chemical bond]

When the structural unit (1) contains a divalent aromatic group represented by the formula (4) as Ar ¹ , the structural unit (1) may contain one or two or more kinds of aromatic groups represented by the formula (4) as Ar 1 . Ar ¹ may contain, in addition to the aromatic group represented by the formula (4), another aromatic group which does not belong to the aromatic group represented by the formula (4) and has a fluoroalkyl group.

The polyamide-based resin contained in the optical film of the present invention has at least a structural unit (1) and a structural unit (3) as described above, and the resin usually has a plurality of structural units (1), a plurality of structural units (3), and any other structural units. In the present specification, the term that the structural unit (1) includes the aromatic group represented by the formula (4) as Ar ¹ means that at least a part of the structural unit (1) is included in the plurality of structural units (1) contained in the polyamide-based resin. Ar ¹ in is represented by formula (4). The above description is also applicable to other descriptions in this specification.

As the fluoroalkyl group having 1 to 12 carbon atoms in R ¹ , the above descriptions about the fluoroalkyl group having 1 to 12 carbon atoms in Ar ¹ are also applicable, and the preferred descriptions are also applicable.

n and k independently represent an integer of 1 to 4. From the viewpoint of optical properties, n is preferably an integer of 1 or 2, and more preferably 1. From the viewpoint of the elastic modulus, k is preferably an integer of 1 or 2, and more preferably 1. Here, when n and/or k represent an integer of 2 to 4, a plurality of R ¹ may be the same or different from each other, but from the viewpoint of solubility in a solvent, a plurality of R ¹ may be present Preferably they are the same as each other. It is more preferable that k is 1 and n is 2, or k is 2 and n is 1, from the viewpoint that the elastic modulus of the optical film is easily increased and the humidity expansion coefficient is easily lowered.

The positions of the two chemical bonds in the formula (4) are not particularly limited, and may be any of the ortho, meta, and para positions, but it is easy to increase the elastic modulus of the optical film and to reduce the humidity expansion coefficient. From the viewpoint of , the chemical bonds are preferably located in para positions to each other.

Preferable examples of the divalent aromatic group represented by the formula (4) include: R ¹ in the formula (4) represents a perfluoroalkyl group having 1 to 12 carbon atoms, k is 1 or 2, and n is an aromatic group in which 1 or 2, and/or 2 bonds are located in the para position to each other.

In one preferred embodiment of the present invention in which the structural unit represented by the formula (1) contained in the polyamide-based resin contained in the optical film of the present invention contains the divalent aromatic group represented by the formula (4) as Ar ¹ , it is easy to From the viewpoint of increasing the elastic modulus of the optical film and easily reducing the humidity expansion coefficient, when the total of the structural units represented by the formula (1) contained in the polyamide-based resin is taken as 100 mol %, Ar ¹ in the formula (1) The ratio of the structural unit that is the divalent aromatic group represented by the formula (4) is preferably 70 to 100 mol %, more preferably 80 to 100 mol %, still more preferably 90 to 100 mol %, and the formula (1) may be In all the structural units represented by ), Ar ¹ is a divalent aromatic group represented by the formula (4).

As a preferable example of the bivalent aromatic group represented by formula (4), the aromatic group represented by formula (4a) in which the chemical bond in formula (4) is located in a para position is mentioned.

[Chemical formula 15]

[In formula (4a), R ³ to R ⁶ independently represent a hydrogen atom or a fluoroalkyl group having 1 to 12 carbon atoms, wherein at least one of R ³ to R ⁶ represents a carbon number of 1 to 12 fluoroalkyl, k represents an integer from 1 to 4, * represents a chemical bond]

From the viewpoints that the elastic modulus of the optical film can be easily increased and the humidity expansion coefficient can be easily lowered, when k in the formula (4a) is 1, at least one of R ³ to R ⁶ represents a carbon atom having 1 to 12 carbon atoms. A fluoroalkyl group, preferably at least two of R ³ to R ⁶ represent a fluoroalkyl group having 1 to 12 carbon atoms, more preferably at least R ³ and R ⁵ represent a fluoroalkyl group having 1 to 12 carbon atoms, and further Preferably, R ³ and R ⁵ represent a fluoroalkyl group having 1 to 12 carbon atoms, and R ⁴ and R ⁶ represent a hydrogen atom. From the viewpoints that the elastic modulus of the optical film can be easily increased and the humidity expansion coefficient can be easily lowered, when k in the formula (4a) is 2, the groups on the first benzene ring are R ³ to R ³⁶ , and the third 2 When the group on the benzene ring is used as R ^3' to R ^6' , preferably at least two of R ³ to R ⁶ and R ^3' to R ^6' represent a fluoroalkyl group having 1 to 12 carbon atoms, and more Preferably, at least R ⁴ and R ^6' present at positions close to the single bond connecting the two benzene rings represent a fluoroalkyl group having 1 to 12 carbon atoms, and more preferably R ⁴ and R ^6' represent carbon atoms A fluoroalkyl group having a number of 1 to 12, and R ³ , R ⁵ , R ⁶ and R ^3' to R ^5' represent a hydrogen atom. As the fluoroalkyl group having 1 to 12 carbon atoms, the above description about the fluoroalkyl group having 1 to 12 carbon atoms in Ar ¹ applies similarly, and the preferred description also applies. It is preferable that k in Formula (4a) is an integer of 1 or 2 from the viewpoint that the elastic modulus of the optical film is easily increased and the humidity expansion coefficient is easily lowered. From the viewpoint of easily improving the pencil hardness of the optical film, k in the formula (4a) is preferably 2.

When Z ¹ in the formula (3) represents Ar ¹ , the above description about Ar ¹ in the formula (1) is applied to Z ¹ in the formula (3) in the same manner. In addition, the above description regarding Ar ¹ in the formula (1) is also applicable to Ar ³ in the formula (3b).

When Z ¹ in formula (3) represents a divalent organic group other than Ar ¹ , Z ¹ is a divalent organic group other than a divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms. The group includes, for example, a hydrocarbon group having 1 to 8 carbon atoms or a fluorine-substituted group that does not belong to the divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms described for Ar ¹ . A divalent organic group having 4 to 40 carbon atoms including a cyclic structure (preferably an alicyclic structure, an aromatic ring structure, and a heterocyclic structure) substituted with a hydrocarbon group having 1 to 8 carbon atoms. Examples of the divalent organic group having 4 to 40 carbon atoms including a cyclic structure include formula (20), formula (21), formula (22), formula (23), formula (24), formula ( 25), formula (26), formula (27), formula (28) and formula (29) in the chemical bond of the group represented by the non-adjacent two groups replaced by hydrogen atoms, and have a thiophene ring structure the group.

[Chemical formula 16]

It should be noted that among these groups,

Substitute two non-adjacent chemical bonds of groups represented by formula (26) or formula (26') described later, which are substituted with a fluorine-substituted hydrocarbon group having 1 to 8 carbon atoms and wherein W ¹ is a single bond. A group derived from a hydrogen atom,

The chemical bonds of the groups represented by formula (28) and formula (29) or formula (28') and formula (29') described later, which are substituted with a fluorine-substituted hydrocarbon group having 1 to 8 carbon atoms, are not compatible with each other. A group obtained by replacing two adjacent hydrogen atoms with hydrogen atoms, and

The group having a thiophene ring structure substituted with a fluorine-substituted hydrocarbon group having 1 to 8 carbon atoms belongs to the divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms described for Ar ¹ , Therefore, it does not belong to Z ¹ in the formula (3) in this mode.

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-, -SO ₂ -, -CO-, -O-Ar-O-, -Ar-O-Ar-, -Ar-CH ₂ -Ar-, -Ar-C(CH ₃ ) ₂ -Ar- or -Ar-SO ₂ -Ar-. Ar represents an arylene group having 6 to 20 carbon atoms in which a hydrogen atom may be substituted with a fluorine atom, and a specific example thereof includes a phenylene group.

As Z ¹ in the formula (3), the divalent organic group having 4 to 40 carbon atoms including a cyclic structure is more preferably the formula (20'), the formula (21'), and the formula (22'). ), formula (23'), formula (24'), formula (25'), formula (26'), formula (27'), formula (28') and a divalent organic group represented by formula (29') .

[Chemical formula 17]

[In the formulas (20') to (29'), W ¹ and * have the same definitions as in the formulas (20) to (29)]

For the polyamide-based resin, from the viewpoint of easily improving the film formability of the varnish and easily obtaining the uniformity of the optical film, it is preferable that, in addition to the structural unit represented by the formula (1), and/or having the formula ( When Z ¹ in 3) is a structural unit represented by any one of the above formulae (20') to (29'), especially in the case where Z ¹ in the formula (3) is represented by the following formula (7) In the case of the represented structural unit, in addition to this structural unit, it has a carboxylic acid-derived structural unit represented by the following formula (d1).

[Chemical formula 18]

[In formula (d1), R ^e independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, R ^f represents ^Re or -C(=O)-*, * represents chemical bond]

In R ^e , as 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, the following formula (5 ) in Ar ² are exemplified by an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. Specific examples of the structural unit (d1) include a structural unit in which both R ^e and R ^f are hydrogen atoms (a structural unit derived from a dicarboxylic acid compound), and R ^e is both a hydrogen atom and R ^f represents -C. A structural unit of (=O)-* (a structural unit derived from a tricarboxylic acid compound) and the like.

In the structural unit represented by formula (3), as Z ¹ , it is preferable to contain a divalent organic group represented by formula (7a), and it is more preferable to contain a divalent organic group represented by formula (7).

[Chemical formula 19]

[In formula (7a), R ^g and R ^h independently represent 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. In the aryl group, A, s, and * are the same as A, s, and * in formula (7), and t and u are independently an integer of 0 to 4, wherein s is an integer of 1 to 4, and A is not In the case of a single bond, the hydrogen atoms contained in R ^g and R ^h may be substituted by halogen atoms independently of each other]

[Chemical formula 20]

[In formula (7), R ³¹ to R ³⁸ 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,

A independently represents a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ - , -SO ₂ -, -S-, -CO- or -N(R ³⁹ )-, R ³⁹ represents a hydrogen atom, a monovalent hydrocarbon group with 1 to 12 carbon atoms that may be substituted by a halogen atom, and s is 0 to an integer of 4,

* means chemical bond,

However, when s is an integer of 1 to 4 and A is not a single bond, the hydrogen atoms included in R ³¹ to R ³⁸ may be independently substituted by halogen atoms]

In formula (7a), the chemical bond of each benzene ring may be bonded to any of the ortho, meta or para positions on the basis of -A-, preferably the meta position or the para position. R ^g and R ^h in the formula (7a) independently represent 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. In formula (7a), t and u are preferably 0, but when t and/or u are 1 or more, R ^g and R ^h preferably represent an alkyl group having 1 to 6 carbon atoms, more preferably a carbon atom An alkyl group having a number of 1 to 3. In R ^g and R ^h in the formula (7a), as a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an aryl group having 6 to 12 carbon atoms , respectively, can be exemplified as a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms in the formula (7). lift group.

t and u in formula (7a) are independently an integer of 0 to 4, preferably an integer of 0 to 2, more preferably 0 or 1, and still more preferably 0.

In formula (7) and formula (7a), A represents a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -, -S-, -CO- or -N(R ³⁹ )-, preferably -O- or -S- from the viewpoint of bending resistance of the optical film , more preferably represents -O-.

In formula (7), R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ , R ³⁷ and R ³⁸ independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a carbon atom is an alkoxy group having 1 to 6 or an aryl group having 6 to 12 carbon atoms. Examples of the alkyl group having 1 to 12 carbon atoms, the alkoxy group having 1 to 6 carbon atoms, and the aryl group having 6 to 12 carbon atoms include carbon atoms in Ar ² in the formula (5). The group exemplified above is an alkyl group having 1 to 12 atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. From the viewpoint of the surface hardness and flexibility of the optical film, R ³¹ to R ³⁸ each independently preferably represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or a carbon number of 1 to 3 The alkyl group further preferably represents a hydrogen atom. Here, when s is an integer of 1 to 4 and A is not a single bond, the hydrogen atoms included in R ³¹ to R ³⁸ may be independently substituted with halogen atoms.

R ³⁹ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms which may be substituted by a halogen atom. Examples of the monovalent hydrocarbon group having 1 to 12 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, and 2-methyl. yl-butyl, 3-methylbutyl, 2-ethyl-propyl, n-hexyl, n-heptyl, n-octyl, tert-octyl, n-nonyl, n-decyl, etc., which may be substituted by halogen atoms . As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned. In the polyamide-based resin, in the structural unit represented by the formula (3), as Z ¹ , one kind of divalent organic group represented by the formula (7) or the formula (7a) may be included, and the formula (7) or the formula may be included. Two or more kinds of organic groups represented by (7a).

In Formula (7) and Formula (7a), s is an integer in the range of 0 to 4, and when s is within this range, the bending resistance and elastic modulus of the optical film are likely to be favorable. Moreover, in Formula (7) and Formula (7a), s is preferably an integer in the range of 0 to 3, more preferably 0 to 2, and still more preferably 0 or 1. When s is within this range, the bending resistance and elastic modulus of the optical film are easily improved.

In the polyamide-based resin contained in the optical film of the present invention, the structural unit represented by the formula (3) may have the structural unit represented by the formula (3') as Z ¹ . In this case, the surface hardness and bending resistance of the optical film are easily improved, and the yellowness (hereinafter, also referred to as YI value) is easily lowered.

[Chemical formula 21]

The above description about Z ¹ in the case where Z ¹ in the formula (3) represents a divalent organic group other than Ar ¹ is also applicable to Z ² in the above-mentioned formula (3a).

X ¹ in formula (1) and X ² in formula (3) represent a divalent organic group, preferably a divalent organic group having 4 to 40 carbon atoms, more preferably a carbon atom having a cyclic structure A divalent organic group with a number of 4 to 40. As a cyclic structure, an alicyclic structure, an aromatic ring, and a heterocyclic structure are mentioned. In the aforementioned organic group, a hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group, and in this case, the hydrocarbon group and the fluorine-substituted hydrocarbon group preferably have 1 to 8 carbon atoms. In one embodiment of the present invention, in the structural unit (1) and the structural unit (3) contained in the polyamide-based resin, as X ¹ and X ² , respectively, one type of organic group may be contained, or two types of organic groups may be contained. more than one organic group. However, when Z ¹ in the formula (3) represents Ar ¹ , X ¹ in the formula (1) and X ¹ in the formula (3) are different from each other.

In a preferred embodiment of the present invention, the structural unit represented by the formula (1) and the structural unit represented by the formula (3) each include the formula (5) from the viewpoint of the ease of increasing the elastic modulus of the optical film and the ease of lowering the humidity expansion coefficient The divalent organic groups represented are X ¹ and X ² .

[Chemical formula 22]

[In formula (5), Ar ² represents a divalent aromatic group which may have a substituent,

V represents a single bond, -O-, diphenylmethylene, fluorenyl, linear, branched or alicyclic divalent hydrocarbon group having 1 to 12 carbon atoms, -SO ₂ -, -S -, -CO-, -PO-, -PO ₂ -, -N(R ^a )- or -Si(R ^b ) ₂ -, wherein the hydrogen atoms contained in the hydrocarbon group independently of each other may be substituted by halogen atoms, R ^a and R ^b independently represent 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 from 0 to 3,

＊Indicates chemical bond]

When the structural unit (1) and the structural unit (3) respectively contain a divalent organic group represented by the formula (5) as X ¹ and X ² , the structural unit (1) and the structural unit (3) may contain the formula ( One or two or more kinds of divalent organic groups represented by 5) are used as X ¹ and X ² . In the structural unit (1) and the structural unit (3), as X ¹ and X ² , respectively, in addition to the divalent organic group represented by the formula (5), a divalent organic group not represented by the formula (5) may be included. Other divalent organic groups of organic groups.

Ar ² in formula (5) represents a divalent aromatic group which may have a substituent. A divalent aromatic group is a monocyclic aromatic ring, a condensed polycyclic aromatic ring, or a group formed by replacing two hydrogen atoms of a ring-collected aromatic ring with a chemical bond, which is the same as the monocyclic aromatic ring in Ar ¹ . Examples and preferred descriptions of aromatic rings, fused polycyclic aromatic rings, or ring-collected aromatic rings are also applicable to monocyclic aromatic rings, fused polycyclic aromatic rings, or ring collections in Ar ² Aromatic ring. When m in Formula (5) is 1 or more, Ar ² which exists in plural may be the same or different from each other.

From the viewpoints that the elastic modulus of the optical film can be easily increased and the humidity expansion coefficient can be easily lowered, the divalent aromatic group which may have a substituent is preferably a chemical bond by replacing 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 may have substituents are replaced by chemical bonds, more preferably benzene or biphenyl which may have substituents A group formed by replacing two hydrogen atoms with a chemical bond.

Examples of the substituent in Ar ² include a halogen group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, or A group in which the hydrogen atoms contained in them are replaced by halogen atoms.

The alkyl group having 1 to 12 carbon atoms may be a linear or branched alkyl group having 1 to 12 carbon atoms, preferably a linear or branched alkane having 1 to 6 carbon atoms base. Examples of such groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, 2-methyl-butyl, 3- Methylbutyl, 2-ethyl-propyl, n-hexyl, n-heptyl, n-octyl, tert-octyl, n-nonyl and n-decyl, 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.

As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned.

The substituent in Ar ² is preferably a halogen group or an alkyl group having 1 to 12 carbon atoms in which a hydrogen atom may be substituted by a halogen atom, more preferably a methyl group, a fluoro group, a chloro group or a trifluoromethyl group .

V in formula (5) represents a single bond, -O-, a diphenylmethylene group, a fluorenyl group, a linear, branched or alicyclic divalent hydrocarbon group having 1 to 12 carbon atoms, - SO ₂ -, -S-, -CO-, -PO-, -PO ₂ -, -N(R ^a )- or -Si(R ^b ) ₂ -. Here, the hydrogen atom contained in the hydrocarbon group may be independently substituted with a halogen atom, and R ^a and R ^b independently represent a hydrogen atom or an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom. Examples of the alkyl group having 1 to 12 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, and 2-methyl. -Butyl, 3-methylbutyl, 2-ethyl-propyl, n-hexyl, n-heptyl, n-octyl, t-octyl, n-nonyl, n-decyl, etc., which may be substituted by halogen atoms. As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned. V in formula (5) is preferably a single bond, -O- or -S-, and more preferably a single bond or -O-, from the viewpoint of easily improving the elastic modulus, humidity expansion coefficient, and bending resistance of the optical film. , more preferably a single bond.

m in the formula (5) represents an integer of 0 to 3, and is preferably 0 to 2, more preferably 0 or 1, and even more preferably 1 from the viewpoint that the elastic modulus of the optical film can be easily increased and the humidity expansion coefficient can be easily lowered. .

One of the present invention in which the structural unit (1) and the structural unit (3) contained in the polyamide-based resin contained in the optical film of the present invention each contain a divalent organic group represented by the formula (5) as X ¹ and X ² In a preferred embodiment, from the viewpoints that the elastic modulus of the optical film can be easily increased and the humidity expansion coefficient can be easily lowered, when the total of the structural unit (1) and the structural unit (3) contained in the polyamide-based resin is taken as 100 mol % , X ¹ in the formula (1) is the total of the structural units of the divalent organic group represented by the formula (5) and X ² in the formula (3) is the structural unit of the divalent organic group represented by the formula (5) The ratio is preferably 70 to 100 mol %, more preferably 80 to 100 mol %, further preferably 90 to 100 mol %, and may be X ¹ and X in all the structural units of the structural unit (1) and the structural unit (3). ² is a divalent organic group represented by formula (5).

In a preferred embodiment of the present invention, the formula (5) is represented by the formula (5a) from the viewpoint that the elastic modulus of the optical film is easily increased and the humidity expansion coefficient is easily lowered.

[Chemical formula 23]

[In formula (5a), R ² represents a fluoroalkyl group having 1 to 12 carbon atoms,

p and q independently represent an integer of 1 to 4, and when p and/or q represent an integer of 2 to 4, a plurality of R ² may be the same or different from each other,

＊Indicates chemical bond]

In addition, formula (5a) corresponds to formula (5) in which V represents a single bond, Ar ² represents a benzene ring substituted with a fluoroalkyl group (R ² ) having 1 to 12 carbon atoms, and m represents 0 to 0. The chemical formula of the integer of 3. When the structural unit (1) and the structural unit (3) respectively contain a divalent organic group represented by the formula (5a) as X ¹ and X ² , the structural unit (1) and the structural unit (3) may contain the formula ( One or two or more kinds of divalent organic groups represented by 5a) are used as X ¹ and X ² . In the structural unit (1) and the structural unit (3), as X ¹ and X ² , respectively, in addition to the divalent organic group represented by the formula (5a), a divalent organic group not represented by the formula (5a) may be included. Other divalent organic groups of organic groups.

R ² in the formula (5a) represents a fluoroalkyl group having 1 to 12 carbon atoms, and as this group, the same description as above about the fluoroalkyl group having 1 to 12 carbon atoms in Ar ¹ applies, and it is preferable that The records also apply.

p and q represent an integer of 1 to 4 independently of each other. From the viewpoint of the elastic modulus and the humidity expansion coefficient of the optical film, p is preferably an integer of 1 or 2, and more preferably 2. From the viewpoint of the elastic modulus and the humidity expansion coefficient of the optical film, q is preferably an integer of 1 or 2, and more preferably 1. Here, when p and/or q represent an integer of 2 to 4, a plurality of R ² may be the same or different from each other, but a plurality of R ² may be present from the viewpoint of solubility in a solvent Preferably they are the same as each other.

The positions of the two chemical bonds in the formula (5a) are not particularly limited, and may be any of ortho, meta, and para positions, but it is easy to increase the elastic modulus of the optical film and to reduce the humidity expansion coefficient. From the viewpoint of , the chemical bonds are preferably located in para positions to each other.

Preferable examples of the divalent aromatic group represented by the formula (5a) include: R ² in the formula (5a) represents a perfluoroalkyl group having 1 to 12 carbon atoms, p is 2, and q is 1 Or 2, and/or 2 aromatic groups in which the chemical bonds are in the para position to each other.

One of the present invention in which the structural unit (1) and the structural unit (3) contained in the polyamide-based resin contained in the optical film of the present invention each contain a divalent organic group represented by the formula (5a) as X ¹ and X ² In a preferred embodiment, from the viewpoints that the elastic modulus of the optical film can be easily increased and the humidity expansion coefficient can be easily lowered, when the total of the structural unit (1) and the structural unit (3) contained in the polyamide-based resin is taken as 100 mol % , X ¹ in the formula (1) is the total of the structural units of the divalent organic group represented by the formula (5a) and X ² in the formula (3) is the structural unit of the divalent organic group represented by the formula (5a) The ratio is preferably 70 to 100 mol %, more preferably 80 to 100 mol %, further preferably 90 to 100 mol %, and may be X ¹ and X in all the structural units of the structural unit (1) and the structural unit (3). ² is a divalent organic group represented by formula (5a).

In a preferred embodiment of the present invention, the formula (5a) is represented by the formula (5b) from the viewpoints that the elastic modulus of the optical film is easily increased and the humidity expansion coefficient is easily lowered.

[Chemical formula 24]

[In formula (5b), R ⁷ to R ¹⁴ independently represent a hydrogen atom or a fluoroalkyl group having 1 to 12 carbon atoms, wherein at least one of R ⁷ to R ¹⁴ is a carbon number of 1 to 12 Fluoroalkyl, * indicates chemical bond]

In addition, the formula (5b) corresponds to the chemical formula of an aromatic group in which the chemical bonds in the formula (5a) are located in the para positions and p is 2. In the formula (5b), at least two of R ⁷ to R ¹⁴ preferably represent a fluoroalkyl group having 1 to 12 carbon atoms, from the viewpoints that the elastic modulus of the optical film can be easily increased and the humidity expansion coefficient can be easily lowered, and more Preferably at least R ⁸ and R ¹⁴ represent a fluoroalkyl group having 1 to 12 carbon atoms, more preferably R ⁸ and R ¹⁴ represent a fluoroalkyl group having 1 to 12 carbon atoms, and R ⁷ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² and R ¹³ represent a hydrogen atom. In addition, in the above-described embodiment, the fluoroalkyl group having 1 to 12 carbon atoms is preferably a perfluoroalkyl group having 1 to 12 carbon atoms, more preferably a perfluoroalkyl group having 1 to 6 carbon atoms, and still more preferably is a perfluoroalkyl group having 1 to 4 carbon atoms, more preferably a trifluoromethyl group or a pentafluoroethyl group, and particularly preferably a trifluoromethyl group.

One of the present invention in which the structural unit (1) and the structural unit (3) contained in the polyamide-based resin contained in the optical film of the present invention each contain a divalent organic group represented by the formula (5b) as X ¹ and X ² In a preferred embodiment, from the viewpoints that the elastic modulus of the optical film can be easily increased and the humidity expansion coefficient can be easily lowered, when the total of the structural unit (1) and the structural unit (3) contained in the polyamide-based resin is taken as 100 mol % , X ¹ in the formula (1) is the total of the structural unit of the divalent organic group represented by the formula (5b) and X ² in the formula (3) is the structural unit of the divalent organic group represented by the formula (5b) The ratio is preferably 20 to 100 mol %, more preferably 30 to 100 mol %, still more preferably 40 to 100 mol %, and may be X ¹ and X in all the structural units of the structural unit (1) and the structural unit (3). ² is a divalent organic group represented by formula (5b).

In one preferred embodiment of the present invention, the formula (5b) is represented by the formula (5c).

[Chemical formula 25]

[* in formula (5c) represents a chemical bond]

In addition, since Formula (5b) is a chemical formula contained in Formula (5a), Formula (5a) can also be represented by Formula (5c). The divalent organic group represented by the formula (5c) is the same as that in the formula (5b) where R ⁹ and R ¹¹ represent a trifluoromethyl group, and R ⁷ , R ⁸ , R ¹⁰ , R ¹² , R ¹³ and R ¹⁴ represent hydrogen A group equivalent to a divalent aromatic group of atoms. When the structural unit (1) and the structural unit (3) respectively contain a divalent organic group represented by the formula (5b) or the formula (5c) as X ¹ and X ² , the structural unit (1) and the structural unit (3) Among them, as X ¹ and X ² , respectively, one or two or more divalent organic groups represented by formula (5b) or formula (5c) may be included, and may be in addition to formula (5b) or formula (5c) In addition to the divalent organic group represented, other divalent organic groups that do not belong to the divalent organic group represented by the formula (5b) and the formula (5c) are included.

One of the present invention in which the structural unit (1) and the structural unit (3) contained in the polyamide-based resin contained in the optical film of the present invention each contain a divalent organic group represented by the formula (5c) as X ¹ and X ² In a preferred embodiment, from the viewpoints that the elastic modulus of the optical film is easily increased and the humidity expansion coefficient is easily lowered, when the total of the structural unit (1) and the structural unit (2) contained in the polyamide-based resin is taken as 100 mol % , X ¹ in the formula (1) is the total of the structural units of the divalent organic group represented by the formula (5c) and X ² in the formula (3) is the structural unit of the divalent organic group represented by the formula (5c) The ratio is preferably 70 to 100 mol %, more preferably 80 to 100 mol %, further preferably 90 to 100 mol %, and may be X ¹ and X in all the structural units of the structural unit (1) and the structural unit (3). ² is a divalent organic group represented by formula (5c).

The description about X ¹ in the formula (1) described above is also applicable to X ³ in the formula (3a) and X ⁴ in the formula (3b). Here, X ⁴ is a divalent organic group other than X ¹ . Here, when X ¹ is two or more kinds, one may be designated as X ¹ and the other may be designated as X ⁴ .

The polyamide-based resin contained in the optical film of the present invention may contain, in addition to the structural unit (1) and the structural unit (3), a structural unit represented by the formula (2) (hereinafter, also referred to as "structural unit (2)" )").

[Chemical formula 26]

[In formula (2), X represents a divalent organic group, and Y represents a tetravalent organic group]

In this case, the polyamide-based resin is also referred to as a polyamide-imide resin. In this method, from the viewpoints that the elastic modulus of the optical film can be easily increased and the humidity expansion coefficient can be easily lowered, the structural unit (1), the structural unit (2), and the structural unit (3) contained in the polyamide-based resin are combined with each other. When the total is 100 mol%, the total ratio of the structural unit (1) and the structural unit (2) is preferably 60 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, still more preferably 85 mol% % or more, particularly preferably 90 mol% or more. The upper limit of the said ratio of the sum total of a structural unit (1) and a structural unit (2) should just be less than 100 mol%. In addition, content of a structural unit (1), a structural unit (2), or a structural unit (3) can be measured using ¹ H-NMR, for example, or can be calculated from the input ratio of a raw material.

Y in the structural unit represented by the formula (2) represents a tetravalent organic group, preferably a tetravalent organic group having 4 to 40 carbon atoms, more preferably a tetravalent organic group having a cyclic structure and having 4 to 40 carbon atoms 4-valent organic group. As a cyclic structure, an alicyclic structure, an aromatic ring, and a heterocyclic structure are mentioned. The aforementioned organic group is 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. In this case, the hydrocarbon group and the fluorine-substituted hydrocarbon group preferably have 1 to 8 carbon atoms. In one embodiment of the present invention, in the structural unit (2), as Y, one type of tetravalent organic group may be contained, or two or more types of tetravalent organic groups may be contained. As Y, formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) can be mentioned. and a group represented by formula (29); a group obtained by substituting a hydrogen atom in a group represented by the formula (20) to formula (29) with a methyl group, a fluoro group, a chlorine group or a trifluoromethyl group; and A tetravalent chain hydrocarbon group having 6 or less carbon atoms.

[Chemical formula 27]

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.

Among the groups represented by the formulae (20) to (29), from the viewpoint of the elastic modulus, surface hardness and bending resistance of the optical film, those represented by the formula (26), the formula (28) or the formula (29) are preferred. group, more preferably a group represented by formula (26). In addition, W ¹ is preferably a single bond, -O-, -CH ₂ -, and -CH ₂ - independently of each other, from the viewpoint of easily improving the elastic modulus, surface hardness, and bending resistance of the optical film, and easily reducing the YI value. CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -, more preferably single bond, -O-, -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -, more preferably a single bond, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -.

In a preferred embodiment of the present invention, the structural unit represented by the formula (2) contains a tetravalent organic group represented by the formula (6) as Y.

[Chemical formula 28]

[In formula (6), R ¹⁸ to R ²⁵ 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 ¹⁸ to R ²⁵ may be independently substituted by halogen atoms,

＊Indicates chemical bond]

When the structural unit (2) contains the tetravalent organic group represented by the formula (6) as Y, the elastic modulus of the optical film is easily increased, and the humidity expansion coefficient is easily lowered. In addition, in this case, the solubility of the polyamide-based resin in the solvent is improved, the viscosity of the varnish containing the resin is easily reduced, and the processability of the optical film is easily improved. In addition, it is easy to improve the optical properties of the optical film.

In formula (6), R ¹⁸ , R ¹⁹ , R ²⁰ , R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, and a carbon atom number. is an alkoxy group having 1 to 6 or an aryl group having 6 to 12 carbon atoms. 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 include carbon atoms in Ar ² in the formula (5). The group exemplified above is an alkyl group having 1 to 12 atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. R ¹⁸ to R ²⁵ each independently preferably represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and here, among R ¹⁸ to R ²⁵ The contained hydrogen atoms may be replaced by halogen atoms independently of each other. As this halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned. R ¹⁸ to R ²⁵ are, independently of each other, more preferably hydrogen atom, methyl group, fluorine, from the viewpoints that the elastic modulus of the optical film can be easily increased, the humidity expansion coefficient can be easily lowered, and the surface hardness, bending resistance, and transparency can be easily improved. group, chloro group or trifluoromethyl group, more preferably R ¹⁸ , R ¹⁹ , R ²⁰ , R ²³ , R ²⁴ and R ²⁵ are hydrogen atoms, R ²¹ and R ²² are hydrogen atoms, methyl groups, fluoro groups, chlorine groups group or trifluoromethyl, particularly preferably R ²¹ and R ²² are methyl or trifluoromethyl.

In one preferred embodiment of the present invention in which the structural unit (2) contained in the polyamide-based resin contained in the optical film of the present invention contains the tetravalent organic group represented by the formula (6) as Y, the elasticity of the optical film is easily improved from the viewpoint of From the viewpoint of the modulus and the ease of lowering the humidity expansion coefficient, Y in the formula (2) is a tetravalent value represented by the formula (6) when the total of the structural units (2) contained in the polyamide-based resin is taken as 100 mol %. The ratio of the structural unit of the organic group is preferably 70 to 100 mol %, more preferably 80 to 100 mol %, and still more preferably 90 to 100 mol %. In all the structural units of the structural unit (2), Y is the formula The tetravalent organic group represented by (6).

In a preferred embodiment of the present invention, the formula (6) is represented by the formula (6a).

[Chemical formula 29]

In addition, formula (6a) corresponds to the case where R ²¹ and R ²² in formula (6) are trifluoromethyl groups, and R ¹⁸ , R ¹⁹ , R ²⁰ , R ²³ , R ²⁴ and R ²⁵ are hydrogen atoms chemical formula. When the structural unit (2) contains the tetravalent organic group represented by the formula (6a) as Y, the elastic modulus of the optical film is easily increased, and the humidity expansion coefficient is easily lowered. In addition, in this case, the solubility of the polyamide-based resin in the solvent is improved, the viscosity of the varnish containing the resin is easily reduced, and the processability of the optical film is easily improved. In addition, it is easy to improve the optical properties of the optical film.

In a preferred embodiment of the present invention in which the structural unit (2) contained in the polyamide-based resin contained in the optical film of the present invention contains a tetravalent organic group represented by the formula (6a) as Y, the elasticity of the optical film is easily improved from the viewpoint of From the viewpoint of modulus and easy reduction of the humidity expansion coefficient, Y in the formula (2) is a tetravalent represented by the formula (6a) when the total of the structural units (2) contained in the polyamide-based resin is taken as 100 mol %. The ratio of the structural unit of the organic group is preferably 70 to 100 mol %, more preferably 80 to 100 mol %, and still more preferably 90 to 100 mol %. In all the structural units of the structural unit (2), Y is the formula The tetravalent organic group represented by (6a).

The polyamide-based resin may contain, in addition to the structural units represented by the formula (1) and the formula (2), the structural unit represented by the formula (30) and/or the structural unit represented by the formula (31).

[Chemical formula 30]

In formula (30), Y ¹ is a tetravalent 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 ^Y1 , the group described as Y in formula (2) is mentioned. In one embodiment of the present invention, the polyamide-based resin may contain a plurality of types of Y ¹ , and the plurality of types of Y ¹ may be the same or different from each other.

In formula (31), Y ² is a trivalent 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 Y ² , a group obtained by substituting any one of the chemical bonds of the groups described as Y in formula (2) with a hydrogen atom, and a trivalent chain hydrocarbon group having 6 or less carbon atoms may, for example, be mentioned. . In one embodiment of the present invention, the polyamide-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 ¹ and X ² 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 ¹ and X ² , the groups described as X ¹ and X ² in formulae (1) and (2) may, for example, be mentioned.

In one embodiment of the present invention, the polyamide-based resin is represented by the structural unit represented by the formula (1), the structural unit represented by the formula (2), and the structural unit represented by the formula (3) and the formula (30) included in some cases. and/or the structural unit represented by formula (31). From the viewpoints that the elastic modulus of the optical film can be easily increased, the humidity expansion coefficient can be easily lowered, and the optical properties, surface hardness, and bending resistance can be easily improved, the polyamide-based resins described above are based on the formulas (1) and (2), and In terms of all the structural units represented by the formula (3), the formula (30) and the formula (31) included in the case, the structural unit represented by the formula (1) and the formula (2) is preferably 80 mol % or more, and more preferably 90 mol % or more. mol% or more, more preferably 95 mol% or more. In addition, in the polyamide-based resin, based on all the structural units represented by formula (1) and formula (2) and the formula (3), formula (30) and/or formula (31) included in some cases , the structural units represented by formula (1) and formula (2) 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 input ratio of a raw material.

In one embodiment of the present invention, the content of the polyamide-based resin in the optical film is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, and still more preferably 50 parts by mass or more with respect to 100 parts by mass of the optical film , preferably 99.5 parts by mass or less, more preferably 95 parts by mass or less. When the content of the polyamide-based resin is within the above range, the optical properties and elastic modulus of the optical film are easily improved, and the humidity expansion coefficient is easily lowered.

The weight average molecular weight (Mw) of the polyamide-based resin is 200,000 to 1,000,000 in terms of standard polystyrene. When the weight average molecular weight (Mw) of the polyamide-based resin is less than 200,000, the elastic modulus of the optical film cannot be sufficiently increased, or the humidity expansion coefficient cannot be sufficiently lowered. In addition, when the weight average molecular weight (Mw) of the polyamide-based resin exceeds 1,000,000, the solubility of the polyamide-based resin in a solvent decreases, and it becomes difficult to process an optical film. The weight average molecular weight (Mw) of the polyamide-based resin in terms of standard polystyrene is preferably from the viewpoints that the elastic modulus, surface hardness, and bending resistance of the optical film can be easily improved, and the humidity expansion coefficient of the optical film can be easily lowered. 220,000 or more, more preferably 250,000 or more, still more preferably 270,000 or more, and particularly preferably 300,000 or more. In addition, the weight average molecular weight of the resin is preferably 900,000 or less, more preferably 800,000 or less, from the viewpoints of easily improving the solubility of the polyamide-based resin in the solvent and easily improving the stretchability and processability of the optical film. It is preferably 700,000 or less, particularly preferably 600,000 or less. The weight-average molecular weight can be determined by, for example, GPC measurement and calculated in terms of standard polystyrene, and can be calculated, for example, by the method described in Examples.

The elastic modulus of the optical film of the present invention is preferably 4GPa or more, more preferably 4.5GPa or more, still more preferably 4.8GPa or more, and usually 100GPa or less, from the viewpoint of easily preventing scratches of the optical film. In addition, the elastic modulus can be measured using a tensile tester (distance between grips: 50 mm, tensile speed: 10 mm/min), for example, by the method described in Examples.

The coefficient of humidity expansion (hereinafter, sometimes referred to as CME) of the optical film of the present invention is preferably as follows, from the viewpoint of easily suppressing the expansion and contraction in the plane direction of the optical film when the temperature and humidity are changed in a state where a load is applied to the optical film. 23 ppm or less, more preferably 22 ppm or less, still more preferably 21 ppm or less, and particularly preferably 20 ppm or less. The smaller the coefficient of humidity expansion, the easier it is to suppress the expansion and contraction of the optical film in the plane direction when a load is applied to the optical film when the temperature and humidity are changed. In addition, CME may be the humidity expansion coefficient of the film at 60 degreeC, 90% R.H. and hold|maintained for 1 hour, and can be measured by the method described in an Example, for example.

The total light transmittance and/or light transmittance with respect to light of 300 to 800 nm of the optical film of the present invention is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more, and particularly preferably 91% or more. % or more, usually 100% or less. 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, there is a tendency that a bright display can 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 K7361-1:1997, 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.

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, particularly preferably 2% or less, particularly more preferably 1% or less , it is more preferably 0.5% or less, particularly preferably 0.2% or less, and 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 in accordance with JIS K 7136:2000.

The YI value of the optical film of the present invention 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 YI value 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. In addition, in this specification, the optical property which an optical film is excellent means that the light transmittance is high.

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, and particularly preferably 60 μm or less may be a combination of these upper and lower limits. When the thickness of the optical film is within the above-mentioned range, the elastic modulus of the optical film can be more easily improved. In addition, the thickness of an optical film can be measured using a micrometer, for example, can be measured by the method described in an Example.

The number of times of bending (bending radius R=1 mm) of the optical film of the present invention in a bending resistance test is preferably 150,000 times or more, more preferably 180,000 times or more, and still more preferably 200,000 times or more. When the number of times of bending is equal to or more than the above-mentioned lower limit, it has sufficient bending resistance as a front panel material of a flexible display device or the like. In addition, the number of times of bending in the bending resistance test means that the optical film is repeatedly bent under the condition that the bending radius (curvature radius) R is 1 mm using a bending tester until the time when cracks occur in the film. The number of bending times of the round trip up to now (one round trip is regarded as 1 time).

The pencil hardness of at least one surface of the optical film of the present invention is preferably H or more, and more preferably 2H or more. When the pencil hardness of at least one surface of an optical film is more than the said hardness, it becomes easy to prevent the damage etc. in the said surface of an optical film. In addition, the pencil hardness can be measured according to JIS K 5600-5-4:1999, for example, can be measured by the method described in an Example.

The present invention provides, in addition to the optical film containing the above-mentioned polyamide-based resin, the above-mentioned polyamide-based resin suitable for producing the optical film. The polyamide-based resin may be, for example, a polyamide-based resin having a weight average molecular weight of 200,000 to 1,000,000, the polyamide-based resin having at least the aromatic group represented by the formula (1) and containing the aromatic group represented by the formula (4) as the The structural unit of Ar ¹ in the formula (1), and the structural unit represented by the formula (3).

[Chemical formula 31]

[In formula (1), Ar ¹ represents a divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms,

X ¹ represents a divalent organic group]

[Chemical formula 32]

[In formula (4), R ¹ represents a fluoroalkyl group having 1 to 12 carbon atoms,

n and k independently represent an integer of 1 to 4, wherein, when n and/or k represent an integer of 2 to 4, a plurality of R ¹ may be the same or different from each other,

*Indicates chemical bond]

[Chemical formula 33]

[In formula (3), Z ¹ represents Ar ¹ , or a divalent organic group other than Ar ¹ , and Ar ¹ has the same definition as in formula (1),

X ² represents a divalent organic group, and when Z ¹ represents Ar ¹ , X ^{1 in the formula (1) and X 2 in} the formula (3) are different from each other]

About the example, preferable aspect, etc. of the kind of each symbol in this polyamide-type resin, the ratio of a structural unit, etc., the said description about the polyamide-type resin contained in the optical film of this invention is applicable similarly.

The content of halogen atoms in the polyamide resin is preferably 1 to 60% by mass, more preferably 5 to 55% by mass, and even more preferably 10 to 50% by mass, based on the mass of the polyamide resin. When content of a halogen atom is more than the said lower limit, the elastic modulus of an optical film becomes easy to improve, it becomes easy to reduce a humidity expansion coefficient, and it becomes easy to improve transparency and visibility. When the content of the halogen atom is equal to or less than the above-mentioned upper limit, the synthesis of the resin becomes easy.

When the polyamide-based resin of the present invention is a polyamide-imide resin having a structural unit (2), the imidization rate of the resin is preferably 90% or more, more preferably 93% or more, and even more preferably 96% or more. % or more, 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 rate represents the ratio of the molar amount of imide bonds in the polyamide-based resin to the value twice the molar amount of the structural unit derived from the tetracarboxylic acid compound in the polyamide-based resin . In addition, when the polyamide-based resin contains a tricarboxylic acid compound, the value of twice the molar amount of the structural unit derived from the tetracarboxylic acid compound in the polyamide-based resin and the amount derived from the tricarboxylic acid compound is represented. The ratio of the molar amount of the imide bond in the polyamide-based resin in terms of the total molar amount of the structural unit. In addition, the imidization rate can be calculated|required by IR method, NMR method, etc..

<Production method of resin>

The polyamide-based resin can be produced, for example, using a dicarboxylic acid compound and a diamine compound as main raw materials. Here, the structural unit represented by the above-mentioned formula (1) and formula (3) is a structural unit formed by the reaction of a dicarboxylic acid compound and a diamine compound. Therefore, a polyamide-based resin can be produced using a dicarboxylic acid compound and a diamine compound that form the structural units represented by the above-mentioned formulas (1) and (3).

Moreover, the structural unit represented by said formula (2) which the polyamide-type resin of this invention may have is a structural unit formed by reacting a tetracarboxylic acid compound and a diamine compound. Therefore, in this case, a polyamide-based resin can be produced by further using a tetracarboxylic acid compound and a diamine compound which form the structural unit represented by the above formula (2).

From this viewpoint, the dicarboxylic acid compound preferably contains at least the compound represented by the formula (8).

[Chemical formula 34]

[In formula (8), Ar ¹ is as defined for Ar ¹ in formula (1),

R ^c and R ^d independently represent a hydroxyl group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, or a chlorine atom. ]

In one preferred embodiment of the present invention, the dicarboxylic acid compound is a compound represented by formula (8) in which R ^c and R ^d are chlorine atoms. In addition, instead of the diamine compound, a diisocyanate compound can also be used.

As the dicarboxylic acid compound that can be used for the production of the resin, aromatic dicarboxylic acids having a fluoroalkyl group or acid chloride compounds thereof such as terephthalic acid having a fluoroalkyl group, 4,4'-oxyl group can be preferably used Dibenzoic acid or their acid chloride compounds. In addition to terephthalic acid, 4,4'-oxybisbenzoic acid or their acid chloride compounds, other dicarboxylic acid compounds can also be used. Examples of other dicarboxylic acid compounds include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and acid chloride compounds similar to these, acid anhydrides, and the like, and may be used in combination of two or more. Specific examples include aromatic dicarboxylic acid compounds having a trifluoromethyl group (isophthalic acid; naphthalenedicarboxylic acid; 4,4'-biphenyldicarboxylic acid; 3,3'-biphenyldicarboxylic acid), and compounds in which two benzoic acids having a trifluoromethyl group are linked by a single bond or a phenylene group, and their acid chloride compounds. As specific examples, 2,2'-bis(trifluoromethyl)-4,4'-biphthaloyl chloride and 2,5-bis(trifluoromethyl)terephthaloyl chloride are preferable.

As the dicarboxylic acid compound, the compound represented by the formula (8) and other dicarboxylic acid compounds can be used. As another dicarboxylic acid compound, the dicarboxylic acid compound represented by formula (7') is mentioned.

[Chemical formula 35]

[In formula (7'), R ³¹ to R ³⁸ 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 6 carbon atoms. In the aryl group of 12, the hydrogen atoms contained in R ³¹ to R ³⁸ may be independently substituted by halogen atoms,

A represents single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO _2- , -S-, -CO- or -N(R ³⁹ )-,

R ³⁹ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms which may be substituted by a halogen atom,

s is an integer from 0 to 4,

R ^c and R ^d are as defined for R ^c and R ^d in formula (8)]

In one embodiment of the present invention, the other dicarboxylic acid compound may be a compound represented by formula (7') wherein s is 1 to 4 and A is an oxygen atom.

As a diamine compound which can be used for manufacture of resin, aliphatic diamine, aromatic diamine, and these mixtures are mentioned, for example. In addition, the "aromatic diamine" in this embodiment means the diamine in which an amino group couple|bonded directly to an aromatic ring, and may contain an aliphatic group or another substituent in a part of the structure. The aromatic ring may be a single ring or a condensed ring, and examples thereof include, but are not limited to, a benzene ring, a naphthalene ring, an anthracene ring, and a fluorene ring. Among these, a benzene ring is preferable. In addition, the "aliphatic diamine" refers to a diamine in which an amino group is directly bonded to an aliphatic group, and may contain an aromatic ring and other substituents 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. These can be used individually or in combination of 2 or more types.

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, more preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 1,4-bis(4-aminophenoxy)benzene, bis[4-(4-aminophenoxy) ) phenyl] sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl) -4,4'-Diaminobiphenyl (TFMB), 4,4'-bis(4-aminophenoxy)biphenyl. These can be used individually or in combination of 2 or more types.

Among the above-mentioned diamine compounds, from the viewpoints of high surface hardness, high transparency, high flexibility, high bending resistance, and low colorability of the optical film, it is preferable to use a group selected from the group consisting of aromatic diamines having a biphenyl structure. 1 or more of them. 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. One or more of the group consisting of 4'-diaminodiphenyl ether, and more preferably 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB) is used.

When a tetracarboxylic acid compound is used in the manufacture of resin, the tetracarboxylic acid compound includes aromatic tetracarboxylic acid compounds such as aromatic tetracarboxylic dianhydride; and aliphatic tetracarboxylic acid such as aliphatic tetracarboxylic dianhydride. Carboxylic acid compounds, etc. The tetracarboxylic acid compound may be used alone or in combination of two or more. In addition to the dianhydride, the tetracarboxylic acid compound may be a tetracarboxylic acid compound analog such as an acid chloride compound.

Specific examples of the aromatic tetracarboxylic dianhydride include non-condensed polycyclic aromatic tetracarboxylic dianhydrides, monocyclic aromatic tetracarboxylic dianhydrides, and condensed polycyclic aromatic dianhydrides. Tetracarboxylic dianhydride. Examples of the non-condensed polycyclic aromatic tetracarboxylic dianhydride include 4,4'-oxydiphthalic dianhydride, 3,3',4,4 '-benzophenone tetracarboxylic dianhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 2,2 ',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propanedi Anhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenoxyphenyl)propane dianhydride, 4,4'-(hexamethylene dianhydride) Fluoroisopropylidene) diphthalic anhydride (4,4'-(hexafluoroisopropylidene)diphthalic dianhydride, sometimes described as 6FDA), 1,2-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1 ,1-bis(2,3-dicarboxyphenyl)ethanedianhydride, 1,2-bis(3,4-dicarboxyphenyl)ethanedianhydride, 1,1-bis(3,4-bis Carboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, 4,4'-(p-phenylenedioxy (p-phenylenedioxy)) diphthalic anhydride, 4,4'-(m-phenylenedioxy)) diphthalic anhydride. Moreover, as monocyclic aromatic tetracarboxylic dianhydride, for example, 1,2,4,5-benzenetetracarboxylic dianhydride is mentioned, and as condensed polycyclic aromatic tetracarboxylic dianhydride, Examples are 2,3,6,7-naphthalenetetracarboxylic dianhydride.

Among these, 4,4'-oxybisphthalic anhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-diphthalic anhydride, Benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic 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-dicarboxyphenoxyphenyl)propane dianhydride, 4,4'-(hexafluoroisopropylidene)bisphthalic anhydride (6FDA), 1,2-bis(2 ,3-Dicarboxyphenyl)ethanedianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethanedianhydride, 1,2-bis(3,4-dicarboxyphenyl)ethane Dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane Dianhydride, 4,4'-(tere-phenylenedioxy)diphthalic anhydride, and 4,4'-(isophenylenedioxy)diphthalic anhydride, more preferably 4,4' -Oxydiphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 4,4'-(hexa Fluoroisopropylidene)diphthalic anhydride (6FDA), bis(3,4-dicarboxyphenyl)methane dianhydride and 4,4'-(terephenylenedioxy)diphthalic anhydride. These can be used individually or in combination of 2 or more types.

Cyclic or acyclic aliphatic tetracarboxylic dianhydride is mentioned as aliphatic tetracarboxylic dianhydride. The cycloaliphatic tetracarboxylic dianhydride is a tetracarboxylic dianhydride having an alicyclic hydrocarbon structure, and specific examples thereof include 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1 , 2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride and other cycloalkane tetracarboxylic dianhydrides, bicyclo[2.2.2]oct-7-ene -2,3,5,6-tetracarboxylic dianhydride, dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride and their positional isomers. These can be used individually or in combination of 2 or more types. Specific examples of the acyclic aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-pentanetetracarboxylic dianhydride, and the like, These can be used individually or in combination of 2 or more types. In addition, a cycloaliphatic tetracarboxylic dianhydride and an acyclic aliphatic tetracarboxylic dianhydride can also be used in combination.

Among the above-mentioned tetracarboxylic dianhydrides, 4,4'-oxybisphthalic anhydride is preferable from the viewpoint of high surface hardness, high transparency, high flexibility, high bending resistance, and low colorability of the optical film , 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetrakis Formic dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 4,4'-(hexafluoro isopropylidene)diphthalic anhydride, and mixtures thereof, more preferably 3,3',4,4'-biphenyltetracarboxylic dianhydride and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride Dicarboxylic anhydride, and a mixture thereof, more preferably 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA).

In addition, the above-mentioned polyamide-based resin may contain tetracarboxylic acid and tricarboxylic acid, and their anhydrides and derivatives in addition to the above-mentioned tetracarboxylic acid compound within the range that does not impair various physical properties of the optical laminate. The product obtained by the reaction.

As a 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 anhydride of 1,2,4-benzenetricarboxylic acid; 2,3,6-naphthalenetricarboxylic acid-2,3-anhydride; phthalic anhydride and benzoic acid through a single bond, -O- , -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ - or a phenylene compound.

In the manufacture of resin, the usage-amount of a diamine compound and a dicarboxylic acid compound, and the usage-amount of the tetracarboxylic-acid compound used in some cases can be suitably selected according to the ratio of each structural unit of a desired polyamide-type resin.

In the production of the resin, the reaction temperature of the diamine compound, the dicarboxylic acid compound, and the tetracarboxylic acid compound used in some cases is not particularly limited. °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 that is inactive for 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, Alcohol-based solvents such as 1-methoxy-2-propanol, 2-butoxyethanol, propylene glycol monomethyl ether; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone Esters, γ-valerolactone, propylene glycol methyl ether acetate, ethyl lactate and other ester solvents; acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, methyl isobutyl Ketone-based solvents such as ketones; aliphatic hydrocarbon solvents such as pentane, hexane, and heptane; alicyclic hydrocarbon solvents such as ethylcyclohexane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile-based solvents such as acetonitrile; tetrahydrofuran and Ether-based solvents such as dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; amide-based solvents such as N,N-dimethylacetamide and N,N-dimethylformamide; dimethylsulfone, Sulfur-containing solvents such as dimethyl sulfoxide and sulfolane; carbonate-based solvents such as ethylene carbonate and propylene carbonate; and combinations thereof, and the like. Among these, from the viewpoint of solubility, an amide-based solvent can be preferably used.

In the case of producing a polyamide-based resin (polyamideimide-based resin) having a structural unit (2) in addition to the structural unit (1) and the structural unit (3) and having a weight average molecular weight of 200,000 to 1,000,000, the production The method 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 of the optical film and easily reducing the humidity expansion coefficient, it is preferable to use a method that adds a dicarboxylic acid compound in batches. A production method of reacting a diamine compound, a tetracarboxylic acid compound, and a dicarboxylic acid compound to produce a polyamideimide-based resin; preferably, a polyamide-based resin is produced by a method comprising: The step (I) of reacting the tetracarboxylic acid compound to produce the intermediate (A), and the step (II) of reacting the intermediate (A) with a dicarboxylic acid compound (preferably the compound represented by the formula (8)), and In this step (II), the dicarboxylic acid compound is added in batches.

In the polyamide-based resin contained in the optical film of the present invention, since Ar ¹ in the above-mentioned formula (1) is a divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms, it is considered that A specific part in the skeleton of the polyamide-based resin has moderate rigidity and intermolecular repulsion. When producing a polyamide-based resin having such a structure without using a method of adding a dicarboxylic acid compound in batches, it may be difficult to keep the weight average molecular weight of the polyamide-based resin within the above-mentioned range. In addition, although the reason is not clear, it is thought that the most suitable resin for increasing the elastic modulus of the optical film and reducing the humidity expansion coefficient can be obtained by using the method of batch addition.

Therefore, the polyamide-based resin contained in the optical film of the present invention and the polyamide-based resin of the present invention are preferably those obtained by adding a dicarboxylic acid compound in batches and reacting a diamine compound, a tetracarboxylic acid compound, and a dicarboxylic acid compound. The resin obtained by the production method is more preferably a step (I) comprising reacting a diamine compound and a tetracarboxylic acid compound to generate an intermediate (A), and using the intermediate (A) with a dicarboxylic acid compound (preferably The compound represented by the formula (8)) is a step (II) of reacting, and the resin obtained by the method for producing the dicarboxylic acid compound is added in batches in the step (II). A polyamide amide having at least the above-mentioned structural unit (1), structural unit (2), and structural unit (3) and having a weight average molecular weight of 200,000 to 1,000,000 is produced by a production method including a step of adding a dicarboxylic acid compound in batches In the case of an imine-based resin, it is easy to adjust the weight average molecular weight of the polyamide-based resin within the above range.

Step (I) of reacting a diamine compound and a tetracarboxylic acid compound to generate an intermediate (A) when a polyamideimide-based resin is produced by the production method including the above-mentioned steps (I) and (II) ) of the reaction 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 (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 carried out under stirring in air or in an inert gas atmosphere such as nitrogen and argon, and may be carried out under normal pressure, under pressure, or under reduced pressure. In a preferable embodiment, stirring is performed under normal pressure and/or the said 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 batches. The dicarboxylic acid compound is added in batches 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 polyamide-based resin is easily increased by adding the dicarboxylic acid compound in batches instead of adding it all at once. It should be noted that, in this specification, adding in batches means adding the dicarboxylic acid compound to be added several times, and more specifically, dividing the added dicarboxylic acid into a specific amount at predetermined intervals (predetermined time) and added separately. The prescribed interval (prescribed time) also includes a very short interval (or time), so continuous addition (or continuous feeding) is also included in batch addition.

In the step (II), the number of batches when adding the dicarboxylic acid compound in batches 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 even more preferably 2 to 20 times. 3 to 6 times. When the number of batches is within the above range, the molecular weight of the polyamide-based resin tends to be increased.

The dicarboxylic acid compound may be added in equal amounts or in unequal amounts. The time between each addition (sometimes referred to as the addition interval) may all be the same or different. In addition, in the case of adding two or more dicarboxylic acid compounds, the term "batch addition" means that the total amount of all the dicarboxylic acid compounds is added in batches, and the batch method of each dicarboxylic acid compound is not particularly limited. For example, each of the dicarboxylic acid compounds may be separately added in one batch or in batches, or each of the dicarboxylic acid compounds may be added in batches together, or a combination of these may be used.

In the step (II), it is preferable to add the relative molecular weight 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 %, and more preferably 2 to 25 mol %, based on 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 even more preferably 5°C to room temperature (about 25°C). In addition, the reaction may be carried out under stirring in air or in an inert gas atmosphere such as nitrogen and argon, and may be carried out under normal pressure, under pressure, or under reduced pressure. In a preferred embodiment, the step (II) is performed under normal pressure and/or the above-mentioned inert gas atmosphere while stirring.

In the step (II), after the dicarboxylic acid compound is added in batches, 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) is reacted with a dicarboxylic acid compound to obtain a polyamideimide precursor. Therefore, the polyamideimide precursor means 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 before imidization (before ring closure) of polyamideimide.

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，优选与酰亚胺化催化剂一同使用酸酐。酸酐可举出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。In the case of producing a polyamide-based resin further having a structural unit (2), the method for producing a polyamide-based resin may further include imidizing a polyamideimide precursor in the presence of an imidization catalyst. The imidization step (III). By supplying the polyamideimide precursor obtained in the step (II) to the step (III), the structural unit portion having a polyamic acid structure in the structural unit of the polyamideimide precursor is imidized (ring closure), a polyamide-based resin containing the structural unit represented by the formula (1), the structural unit represented by the formula (2), and the structural unit represented by the formula (3) can be obtained. In the imidization step, imidization may be performed in the presence of an imidization catalyst. 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. Moreover, it is preferable to use an acid anhydride together with an imidation catalyst from a viewpoint of easily promoting an imidation reaction. The acid anhydrides include conventional acid anhydrides that can be used in the imidization reaction, 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.

Polyamide-based resins can be separated by conventional methods, such as separation means such as filtration, concentration, extraction, crystallization, recrystallization, column chromatography, and separation and purification by means of a combination of these, and the like. 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 polyamide-based resin to precipitate the resin, concentrating, filtering, drying, and the like.

＜Packing＞

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, more preferably 1 to 8 parts by mass, relative to the mass of the polyamide-based resin contained in the optical film. , 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 relative to the mass of the optical film.

(Manufacturing method of optical film)

The manufacturing method of the optical film of this invention is not specifically limited, For example, the manufacturing method including the following steps may be used.

(a) a step of preparing a polyamide-based resin composition (hereinafter, also referred to as "varnish") containing at least the above-mentioned polyamide-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) Step of drying the applied liquid (coating film) to form an optical film (optical film forming step)

In the varnish preparation step, a varnish is prepared by dissolving a polyamide-based resin in a solvent, adding additives such as the above-mentioned 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 a solvent that can dissolve the resin, such as the following varnish. The silica sol obtained by replacing the dispersion liquid of the silica sol containing silica particles with the solvent used.

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; lactone-based solvents such as γ-butyrolactone 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 combinations thereof. Among these, an amide-based solvent or a lactone-based solvent is preferable. 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 of the varnish is preferably 1 to 25% by mass, more preferably 5 to 20% by mass, and further preferably 5 to 15% by mass.

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, the optical film can be formed by drying the coating film and peeling off 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.

(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.

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, but 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 can be 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 mutually be 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, and the formation speed of the network obtained from the cationically polymerizable compound of the hard coat layer obtained is accelerated, even if In the region where it is mixed with the radically polymerizable compound, unreacted monomers do not remain 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 relative 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 become 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. use. The aforementioned additives may further contain inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, antifouling agents, and the like.

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.

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.

In one 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. As a flexible display device, all display devices which have a flexible characteristic can be mentioned.

[Flexible Display Device]

The present invention also provides a flexible display device comprising 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, the polarizing plate, the touch sensor, or the window film is preferred from the viewing side. , the touch sensor, and the polarizing plate are stacked in sequence. 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 window, the polarizing plate, and the 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 circularly polarized light component or a left-handed circularly polarized light component by laminating a λ/4 retardation plate on a linear 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 aforementioned liquid crystalline compound only needs to have a property of exhibiting a liquid crystal state, and when it has a high-order alignment state such as smectic, it is preferable because it exhibits high polarization performance. 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 aforementioned base material serves as a protective film, a retardation plate, and a transparent base material for 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 imparts a retardation of λ/4 in the direction perpendicular to the advancing direction of the incident light (that is, 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. If necessary, 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 aforementioned base material serves as a protective film, a retardation plate, and a transparent base material for 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 -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 the display portion on the display panel that displays the screen, and is an area that senses the user's touch, and the inactive area is an area corresponding to the non-display portion of the display device that does not display the 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 an optical adjustment layer can be improved by the said inorganic particle.

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]

The layers forming the laminate for a flexible display device, such as window films, polarizers, and touch sensors, and film members such as linear polarizers and λ/4 retardation plates constituting the layers can be bonded with an adhesive. As the adhesive, water-based adhesives, organic solvent-based adhesives, solvent-free adhesives, solid adhesives, solvent-volatile adhesives, moisture-curable adhesives, and heat-curable adhesives can be used. Adhesives, anaerobic curing adhesives, active energy ray curing adhesives, curing agent mixed adhesives, hot melt adhesives, pressure sensitive adhesives, pressure sensitive adhesives, Commonly used adhesives such as wet 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 bonding 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 a cationically polymerizable compound that can be used in the active energy ray-curable composition, an epoxy compound is particularly 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 may 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. or 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 polyamide 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 the S-S curve was measured under the conditions of a distance between clips of 50 mm and a tensile speed of 10 mm/min, and the elastic modulus was calculated from the slope.

<Measurement of light transmittance>

According to JIS K 7105: 1981, the total light transmittance Tt of the samples was measured for the optical films obtained in the Examples and Comparative Examples using a fully automatic direct reading haze computer HGM-2DP manufactured by Suga Test Instruments Co., Ltd. .

<Measurement of Moisture Expansion Coefficient (CME)>

The measurement was performed using "TMA/SS6100 type" manufactured by Hitachi High-Tech Science Corporation. In a nitrogen atmosphere, a film with a width of 2 mm and a length of 20 mm was placed on a chuck (the distance between the chucks was 10 mm), and under a load of 20 mN, the film was kept at 60° C. and 0% R.H. until saturation, and then controlled to be At 60°C, 90% R.H., the humidity expansion coefficient of the film was measured when it was held for 1 hour. In addition, regarding the humidity expansion coefficient, let the length of the film be L (mm), and let the amount of change in the length of the film before and after holding the above-mentioned 90% R.H. condition for 1 hour be ΔL (mm) , and the amount of change in humidity was defined as ΔM (%), and it was calculated by the following formula.

Humidity expansion coefficient = (1/L)(ΔL/ΔM)

<YI value of film>

In accordance with JIS K 7373:2006, the YI value (Yellow Index, yellowness index) of the sample was measured using an ultraviolet-visible-near-infrared spectrophotometer V-670 manufactured by JASCO Corporation. After the background measurement was performed without the sample, the sample was placed in the sample holder, the transmittance with respect to light of 300 to 800 nm was measured, and tristimulus values (X, Y, Z) were obtained. The YI value was calculated based on the following formula.

YI=100×(1.2769X-1.0592Z)/Y

＜Haze＞

The haze of the optical film was measured according to JIS K7105: 1981 using a fully automatic direct reading haze computer HGM-2DP manufactured by Suga Test Instruments Co., Ltd.

<Measurement of pencil hardness>

As the surface hardness of the polyamide-imide films obtained in Examples and Comparative Examples, the pencil hardness of the film surface was used in accordance with JIS K 5600-5-4:1999. The load was set to 100 g, the scanning speed was set to 60 mm/min, and the presence or absence of damage was evaluated in an environment of 4,000 lux, and the pencil hardness was measured as the surface hardness.

<Measurement of weight average molecular weight>

Gel permeation chromatography (GPC) assay

(1) Pretreatment method

A DMF eluent (10 mmol/L lithium bromide solution) was added to the sample to make the concentration 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 of optical film>

The thicknesses of the polyamide-based resin films obtained in Examples and Comparative Examples were measured using a micrometer ("ID-C112XBS" manufactured by Mitutoyo Co., Ltd.).

<Example 1>

[Preparation of Polyamide-Based Resin (1)]

Under a nitrogen atmosphere, 2,2'-bis(trifluoromethyl)benzidine (TFMB) and N,N-dimethylacetamide (DMAc) were added to a detachable flask equipped with a stirring wing to make the TFMB The solid content was 4.90 mass %, and TFMB was dissolved in DMAc while stirring at room temperature. Next, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) was added to the flask so as to be 30.30 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 in an amount of 5.05 mol % relative to TFMB, and 2,5 in an amount of 27.28 mol % relative to TFMB. -Bis(trifluoromethyl)terephthaloyl chloride (6FTPC), after stirring for 10 minutes, OBBC was further added in an amount of 5.05 mоl% relative to TFMB, and 6FTPC was added in an amount of 27.28 mоl% relative to TFMB, and stirred for 30 minutes. minute. Then, DMAc was added in the same amount as the DMAc added first, and after stirring for 10 minutes, 6FTPC was added so as to be 6.06 mol % with respect to TFMB, and the mixture was stirred for 2 hours. Next, 70.71 mol% of diisopropylethylamine and 4-picoline with respect to TFMB, and 212.12 mol% of acetic anhydride with respect to TFMB were added to the flask, respectively, and after stirring for 30 minutes, The internal temperature was raised to 70°C, and the mixture was further stirred 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-type resin (1) was obtained.

[Manufacture of polyamide-based resin film (1)]

To the obtained polyamide-based resin (1), DMAc was added so that the concentration would be 10% by mass to prepare a polyamide-based resin varnish (1). Using an applicator, the obtained polyamide-based resin varnish (1) was applied to the smooth surface of a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film would be 50 μm. Then, drying was performed 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 polyamide-based resin film (1) having a thickness of 45 μm.

<Example 2>

[Preparation of Polyamide-Based Resin (2)]

In a nitrogen atmosphere, TFMB and DMAc were put into a separable flask equipped with a stirring blade so that the solid content of TFMB was 2.36 mass %, and TFMB was dissolved in DMAc while stirring at room temperature. Next, 6FDA was added to the flask so as to be 30.30 mol % with respect to TFMB, and the mixture was stirred at room temperature for 3 hours. Then, after cooling to 10° C., OBBC was added in an amount of 5.5 mol % relative to TFMB, and 2,2′-bis(trifluoromethyl)-4,4′- was added in an amount of 27.28 mol % relative to TFMB. Biphthaloyl chloride (6FBPDOC) was stirred for 10 minutes, OBBC was further added at 5.05 mоl % with respect to TFMB, and 6FBPDOC was added at 27.28 mоl % with respect to TFMB, followed by stirring for 30 minutes. Then, the same amount of DMAc as the DMAc added first was added, and after stirring for 10 minutes, 6FBPDOC was added so as to be 6.06 mol % with respect to TFMB, and the mixture was stirred for 2 hours. Next, 70.71 mol% of diisopropylethylamine and 4-picoline with respect to TFMB, and 212.12 mol% of acetic anhydride with respect to TFMB were added to the flask, respectively, and after stirring for 30 minutes, The internal temperature was raised to 70°C, and the mixture was further stirred 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-type resin (2) was obtained.

[Manufacture of polyamide-based resin film (2)]

To the obtained polyamide-based resin (2), DMAc was added so that the concentration would be 10% by mass to prepare a polyamide-based resin varnish (2). Using an applicator, the obtained polyamide-based resin varnish (2) was applied to the smooth surface of a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film would be 55 μm. Then, drying was performed 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 polyamide-based resin film (2) having a thickness of 50 μm.

<Comparative Example 1>

[Preparation of Polyamide-Based Resin (3)]

In a nitrogen atmosphere, TFMB and DMAc were put into a separable flask equipped with a stirring blade so that the solid content of TFMB was 5.54 mass %, and TFMB was dissolved in DMAc while stirring at room temperature. Next, 6FDA was added to the flask so as to be 30.20 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 at 10.07 mol% with respect to TFMB, and terephthaloyl chloride (TPC) at 54.35 mol% with respect to TFMB was added, and it stirred for 30 minutes. Then, the same amount of DMAc as the DMAc added first was added, and after stirring for 10 minutes, TPC was added so as to be 6.04 mol % with respect to TFMB, and the mixture was stirred for 2 hours. Next, 70.46 mol% of diisopropylethylamine and 4-picoline with respect to TFMB, and 211.37 mol% of acetic anhydride with respect to TFMB were added to the flask, respectively, and after stirring for 30 minutes, The internal temperature was raised to 70°C, and the mixture was further stirred 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-type resin (3) was obtained.

[Manufacture of polyamide-based resin film (3)]

To the obtained polyamide-based resin (3), DMAc was added so that the concentration would be 10% by mass to prepare a polyamide-based resin varnish (3). Using an applicator, the obtained polyamide-based resin varnish (3) was applied to the smooth surface of a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") so that the thickness of the self-supporting film would be 55 μm. Then, drying was performed 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 polyamide-based resin film (3) having a thickness of 50 μm.

The weight-average molecular weights (Mw) of the polyamide-based resins (1) to (3) obtained, and the elastic modulus, CME, and light transmittance of the polyamide-based resin films (1) to (3) were measured by the above-mentioned methods. , YI value and haze. The obtained results are shown in Table 1. In addition, the pencil hardness of the optical film (1) was 3B, and the pencil hardness of the optical film (2) was 2H.

[Table 1]

Claims (15)

1. An optical film comprising a polyamide-based resin having a weight average molecular weight of 200,000 to 1,000,000, the polyamide-based resin having at least a structural unit represented by formula (1) and a structural unit represented by formula (3), [Chemical formula 1]

In formula (1), Ar ¹ represents a divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms, X ¹ represents a divalent organic group; [Chemical formula 2]

In formula (3), Z ¹ represents Ar ¹ , or represents a divalent organic group other than Ar ¹ , Ar ¹ is the same as defined in the formula (1), X ² represents a divalent organic group, and when Z ¹ represents Ar ¹ , X ^{1 in the formula (1) and X 2 in} the formula (3) are different from each other. 2 . The optical film according to claim 1 , wherein the fluoroalkyl group having 1 to 12 carbon atoms in Ar ¹ in the formula (1) is a perfluoroalkyl group having 1 to 12 carbon atoms. 3 . 3. The optical film according to claim 1 or 2, wherein the structural unit represented by the formula (1) contains an aromatic group represented by the formula (4) as Ar ¹ , [Chemical formula 3]

In formula (4), R ¹ represents a fluoroalkyl group having 1 to 12 carbon atoms, n and k independently represent an integer of 1 to 4, wherein, when n and/or k represent an integer of 2 to 4, a plurality of R ¹ may be the same or different from each other, * indicates chemical bond. 4. The optical film according to claim 3, wherein the two chemical bonds in the formula (4) are located in para positions with each other. 5 . The optical film according to claim 3 , wherein k in formula (4) is 1 or 2. 6 . 6 . The optical film according to claim 3 , wherein R ¹ in formula (4) represents a perfluoroalkyl group having 1 to 12 carbon atoms, and n is 1 or 2. 7 . 7 . The optical film according to claim 1 , wherein the structural unit represented by the formula (1) and the structural unit represented by the formula (3) each contain a divalent organic group represented by the formula (5). 8 . As X ¹ and X ² , [Chemical formula 4]

In formula (5), Ar ² represents a divalent aromatic group which may have a substituent, V represents a single bond, -O-, diphenylmethylene, fluorenyl, linear, branched or alicyclic divalent hydrocarbon group having 1 to 12 carbon atoms, -SO ₂ -, -S -, -CO-, -PO-, -PO ₂ -, -N(R ^a )- or -Si(R ^b ) ₂ -, wherein the hydrogen atoms contained in the hydrocarbon group independently of each other may be substituted by halogen atoms, R ^a and R ^b independently represent 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 from 0 to 3, * indicates chemical bond. 8 . The optical film according to claim 7 , wherein m in formula (5) is 1. 9 . 9. The optical film according to claim 7 or 8, wherein the formula (5) is represented by the formula (5a), [Chemical formula 5]

In formula (5), R ² represents a fluoroalkyl group having 1 to 12 carbon atoms, p and q independently represent an integer of 1 to 4, and when p and/or q represent an integer of 2 to 4, a plurality of R ² may be the same or different from each other, * indicates chemical bond. 10. The optical film of claim 9, wherein the formula (5a) is represented by the formula (5c), [Chemical formula 6]

* in formula (5c) represents a chemical bond. The optical film of any one of Claims 1-10 whose thickness is 10-200 micrometers. 12 . A flexible display device comprising the optical film according to claim 1 . 13. The flexible display device of claim 12, further comprising a touch sensor. 14. The flexible display device according to claim 12 or 13, further comprising a polarizing plate. 15. A polyamide-based resin having a weight average molecular weight of 200,000 to 1,000,000, the polyamide-based resin having at least: represented by the formula (1) and containing an aromatic group represented by the formula (4) as a structural unit of Ar ¹ in the formula (1), and The structural unit represented by formula (3); [Chemical formula 7]

In formula (1), Ar ¹ represents a divalent aromatic group having a fluoroalkyl group having 1 to 12 carbon atoms, X ¹ represents a divalent organic group; [Chemical formula 8]

In formula (4), R ¹ represents a fluoroalkyl group having 1 to 12 carbon atoms, n and k independently represent an integer of 1 to 4, wherein, when n and/or k represent an integer of 2 to 4, a plurality of R ¹ may be the same or different from each other, * means chemical bond; [Chemical formula 9]

In formula (3), Z ¹ represents Ar ¹ , or represents a divalent organic group other than Ar ¹ , Ar ¹ is the same as defined in the formula (1), X ² represents a divalent organic group, and when Z ¹ represents Ar ¹ , X ^{1 in the formula (1) and X 2 in} the formula (3) are different from each other.