JPH10219071A - Thermosetting composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition that can manifest excellent solubility in the solvent, when it is coated, and can develop excellent resistance to solvent after curing and is useful as a display medium and optically anisotropic material by formulating a specific liquid crystalline copolymer and an oxazoline group- bearing compound to the composition. SOLUTION: This thermosetting composition comprises (A) a liquid-crystalline polymer prepared by copollymerizing two or more kinds of monomers selected from a carboxyl (W)-fee polymerizable liquid crystalline monomer (A1 ), a W- bearing liquid crystalline polymerizable monomer (A2 ) and a W-bearing non- liquid crystalline polymerizable monomer (A3 ), (B) a two or more oxazoline groups-bearing compound. In an embodiment, A3 and A2 are constituted with a compound of the formula [R<1> is H, methyl; rings A-D are each an aromatic 6-membered ring; Z<1> -Z<3> are each a direct bond, -CH2 O-; X<1> and X<2> are each H, a halogen; R<2> is W in the case of A2 and is a group other than W, for example, H, a 1-8C (branched) alkyl; 1 is 0-14; (m), (n), (p), (q), (r) are each 0, 1 where 2<=n+p+q+r<=4].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting composition exhibiting a liquid crystal phase after curing, and more specifically, comprises a polymerizable monomer exhibiting a liquid crystal phase and a polymerizable monomer having a carboxylic acid group. The present invention relates to a thermosetting composition comprising a copolymer and a compound having two or more oxazoline groups in a molecule.

[0002]

2. Description of the Related Art In recent years,
Liquid crystal materials are not only applied to display media using reversible motion of liquid crystal molecules such as display elements such as TN type or STN type, but also have physical properties such as orientation, refractive index, dielectric constant, and magnetic susceptibility. Utilizing the anisotropy of properties, retardation plates, polarizing plates,
Applications to optically anisotropic bodies such as light polarizing prisms and various optical filters are being studied.

As described above, in order to obtain stable and uniform optical characteristics, a uniform alignment state of liquid crystal molecules in a liquid crystal state is semi-permanently fixed to an optically anisotropic body having a liquid crystal material as a constituent material. It is essential to obtain a polymer having a high glass transition temperature (hereinafter also referred to as “Tg”), which is stable both thermally and thermally, and which has excellent orientation.

As a means for semi-permanently fixing a uniform alignment state of liquid crystal molecules in a liquid crystal state, for example, a liquid crystal compound having a polymerizable functional group or a polymerizable liquid crystal composition containing such a compound is used. There is already known a method in which a uniform alignment state is semi-permanently fixed by uniformly irradiating an energy ray such as ultraviolet rays while maintaining the liquid crystal state after uniformly aligning the liquid crystal state.

[0005] However, in this method, an expensive photopolymerization initiator is indispensable for photopolymerization, and the mechanical strength is insufficient due to a low molecular weight substance or the like, and when a imide resin or the like is laminated, the liquid crystallinity is low. Had problems such as loss.

As a method for overcoming the drawbacks of polymerization after coating on a substrate, a method of polymerizing a polymerizable liquid crystal composition by light or heat, coating the polymerizable liquid crystal composition on a substrate as a solution, drying the solution, There is known a method in which the liquid crystal is heated to an isotropic liquid and then gradually cooled to fix the liquid crystal state.

However, in order to use this method, it is necessary that the liquid crystalline polymer is excellent in solubility in a solvent. In addition, since the use of halogen-based organic solvents has been restricted in recent years, a liquid crystal polymer excellent in solubility in an organic solvent containing no halogen has been demanded. Polymers of liquid crystalline monomers that have been specifically studied so far have poor solubility or are too high in solubility, and have problems such as loss of liquid crystallinity when laminated with an imide resin or the like. I was

Accordingly, an object of the present invention is to provide a liquid crystalline polymer which is excellent in solubility in a solvent when applied to a substrate and which is excellent in solvent resistance when used.

[0009]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a copolymer of a polymerizable liquid crystal monomer and a polymerizable monomer having a carboxylic acid group, It has been found that a thermosetting composition comprising a compound having two or more oxazoline groups can achieve the above object.

[0010] The present invention has been made based on the above findings, and provides a thermosetting composition comprising the following components (A) and (B). (A); a polymerizable liquid crystal monomer having no carboxylic acid group (a), a polymerizable liquid crystal monomer having a carboxylic acid group (b), and a carboxylic acid group At least 2 selected from the group consisting of non-liquid crystalline polymerizable monomers (c)
A liquid crystalline polymer having a carboxylic acid group, obtained by copolymerizing various kinds of monomers. (B): a compound having two or more oxazoline groups in the molecule.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the thermosetting composition of the present invention will be described in detail. In the liquid crystalline polymer having a carboxylic acid group, which is the component (A) used in the present invention,
Polymerizable liquid crystalline monomer having no carboxylic acid group (a)
Alternatively, as the polymerizable liquid crystal monomer (b) having a carboxylic acid group, the monomer itself has liquid crystallinity, or a compound having an ethylenically unsaturated group showing liquid crystallinity after polymerization. If it is not particularly limited, for example,
A compound represented by the following general formula (I) of the following [Chemical formula 2] (the same as the above [Chemical formula 1]) (However, in the case of (a), R ² is a group other than a carboxyl group, and in the case of (b), R ² is R ² is a carboxyl group).

[0012]

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Here, in the general formula (I), rings A, B,
Examples of the group composed of a 6-membered hydrocarbon ring or a 6-membered heterocyclic ring represented by C and D include 1,4-phenylene, 1,4
-Cyclohexylene, 1,4-cyclohexenylene, dioxanylene, pyridylene, pyrimidylene, and the like, and examples of the condensed ring include naphthylene.

Further, as the alkyl group represented by R ² ,
Methyl, ethyl, propyl, butyl, isobutyl, pentyl, hexyl, heptyl, octyl, and the like, and the alkoxy group includes an alkoxy group corresponding to the above alkyl group.As the alkoxyalkyl group, methoxymethyl, methoxyethyl, Methoxypropyl, ethoxymethyl, ethoxyethyl and the like can be mentioned, and as the fluoroalkyl group, a fluoroalkyl group corresponding to the above alkyl group such as trifluoromethyl and pentafluoroethyl can be mentioned.

The halogen atom represented by R ² , X ¹ and X ² includes, for example, fluorine, chlorine and bromine, and fluorine is preferred because the resulting compound has excellent stability.

Further, 1 represents 0 to 14. When 1 is larger than 14, the stability of the alignment state of the liquid crystalline polymer obtained by polymerizing the liquid crystalline monomer is reduced.

Further, n, p, q and r are each independently 0
Or 1 and 2 ≦ n + p + q + r ≦ 4. When the sum of these is 1, the liquid crystallinity of the obtained polymer may be poor. When the sum is more than 4, the obtained polymer becomes rigid and poor in orientation. May be.

Therefore, the polymerizable liquid crystal monomer (a) having no carboxylic acid group and the polymerizable liquid crystal monomer (b) having a carboxylic acid group are more specifically described. And the former include compound Nos. 3 to 19 shown below. Examples of the latter include the following compound Nos. [Chemical Formula 20] to [Chemical Formula 22]. 18-20. However, the polymerizable liquid crystal monomer (a) and the polymerizable liquid crystal monomer (b) according to the present invention are not limited by the following compounds.

[0019]

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[0020]

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[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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[0031]

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[0032]

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[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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The polymerizable liquid crystal monomers (a) and (b) can be used alone or in combination of two or more, and the polymerizable liquid crystal monomers (a) and / or (b) ) Is preferably 30% by weight or more, more preferably 50% by weight or more in the obtained liquid crystalline polymer [component (A)]. If the total content is less than 30% by weight, the resulting polymer may not exhibit liquid crystallinity, or the temperature range in which the polymer exhibits a liquid crystal phase may be narrowed.

The non-liquid crystalline polymerizable monomer (c) having a carboxylic acid group is, for example, a compound represented by the following general formula (II): Can be

[0041]

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Specific examples of the compound represented by the general formula (II) include, for example, acrylic acid, methacrylic acid, acryloyloxybenzoic acid, methacryloyloxybenzoic acid, 4-acryloyloxybenzoic acid, and 4-methacryloyloxybenzoic acid. Acid, 4- (2-acryloyloxyethyloxy) benzoic acid, 4- (6-methacryloyloxyhexyloxy) benzoic acid, 4-carboxystyrene, 4- (2-carboxyphenoxymethyl) styrene and the like.

In addition, in order to adjust the mechanical properties such as Tg of the obtained liquid crystalline polymer in obtaining the above-mentioned component (A), other than the monomers (a), (b) and (c), Other monomers can be used depending on The other monomer is preferably used in a range in which the above-mentioned monomer (a) and / or (b) does not deviate from the content range. Examples of the other monomer include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate tetrahydrofurfuryl (meth) acrylate, tertiary butyl (meth) acrylate, (Meth) acrylates such as glycidyl (meth) acrylate, trifluoroethyl (meth) acrylate, and tetrafluoropropyl (meth) acrylate; diacetone acrylamide;
Styrene, vinyltoluene and the like can be mentioned.

When the component (A) is obtained, the amount of the monomer having a carboxylic acid group [(a) and (b)] is determined based on the carboxylic acid equivalent of the obtained liquid crystalline polymer. 5
An amount in the range of 00 to 50000, particularly 1000 to 10000 is preferred. If the carboxylic acid equivalent is less than 500, a cured film formed after curing the composition of the present invention may not be able to maintain liquid crystallinity, and if it is more than 50,000, sufficient thermosetting may not be obtained.

Further, at least two selected from the group consisting of the polymerizable liquid crystal monomer (a), the polymerizable liquid crystal monomer (b) and the non-liquid crystal polymerizable monomer (c). The method of copolymerizing the seed monomers is not particularly limited, and examples thereof include a method obtained by thermal polymerization using a radical initiator and a method obtained by photopolymerization using a photoinitiator.

The liquid crystalline polymer as the component (A) preferably has a number average molecular weight of 3,000 to 500,000, particularly preferably 5,000 to 300,000. When the number average molecular weight is less than 3000, the resulting cured film is insufficient in mechanical strength and impractical.
If it is larger than 000, the solubility in an organic solvent is reduced, and it is difficult to apply the solution as a solution to a substrate.

Compounds having two or more oxazoline groups in the molecule (component (B)) used in the present invention (hereinafter referred to as "B")
Examples of “oxazoline compound” include, but are not particularly limited to, for example, 2,2′-bis (2-oxazoline), 2,2′-bis (4-methyl-2-oxazoline),
2,2'-bis (5-methyl-2-oxazoline), 2,2'-bis
(5,5'-dimethyloxazoline), 2,2'-bis (4,4,4 ', 4'
-Tetramethyl-2-oxazoline), 1,2-bis (2-oxazolin-2-yl) ethane, 1,4-bis (2-oxazoline)
2-yl) butane, 1,6-bis (2-oxazolin-2-yl) hexane, 1,8-bis (2-oxazolin-2-yl),
1,4-bis (2-oxazolin-2-yl) cyclohexane,
1,2-bis (2-oxazolin-2-yl) benzene, 1,3-bis (2-oxazolin-2-yl) benzene, 1,4-bis (2-
Oxazolin-2-yl) benzene, 1,2-bis (5-methyl)
2-oxazolin-2-yl) benzene, 1,3-bis (5-methyl-2-oxazolin-2-yl) benzene, 1,4-bis (5
-Methyl-2-oxazolin-2-yl) benzene, bisoxazoline compounds such as 1,4-bis (4,4'-dimethyl-2-oxazolin-2-yl) benzene, and the oxazoline group of the bisoxazoline compound 2 chemical equivalents and polybasic carboxylic acids (eg maleic acid, succinic acid, itaconic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid,
Compounds having a terminal oxazoline group obtained by reacting one chemical equivalent of a carboxyl group of methylhexahydrophthalic acid, chlorendic acid, trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid and the like can be mentioned.

The ratio (molar ratio) of the oxazoline compound (component (B)) to the liquid crystalline polymer (component (A)) is not particularly limited. The carboxylic acid group of the hydrophilic polymer [component (A)] and the oxazoline group of the oxazoline compound [component (B)] react and cure, thereby imparting solvent resistance to the liquid crystalline polymer. Carboxylic acid group / oxazoline group is 0.1 to
It is preferably used to be 10, especially 0.8 to 1.2. When the amount of the oxazoline compound is excessively large (less than the lower limit of the above range), the resulting cured film contains a large amount of unreacted oxazoline compound, so that the solvent resistance may be reduced. Is extremely insufficient (above the upper limit of the above range), the curing is not sufficiently performed, the solvent resistance of the obtained cured film is reduced, or an unreacted carboxylic acid group remains in a large amount, so that the electric resistance of the cured film becomes large. It may adversely affect characteristics.

As a curing method for obtaining a cured film using the thermosetting composition of the present invention, generally known methods can be used. For example, the components (A) and (B) can be dissolved in a solvent. After dissolving to obtain a coating liquid, the obtained coating liquid is applied onto a substrate such as a glass substrate by a spin coater or the like, and then cured by heating at a desired temperature and time.

The cured film obtained from the thermosetting composition of the present invention can be used for various media such as a display medium such as a display element and an optically anisotropic body such as a retardation plate, a polarizing plate, a light polarizing prism, and various optical filters. Used for liquid crystal materials.

[0051]

The thermosetting composition of the present invention will be described in more detail with reference to Synthesis Examples and Examples. However, the present invention is not limited by these Synthesis Examples and Examples.

First, specific synthetic examples of the compounds used in Examples and Comparative Examples are shown. [Synthesis of Copolymers No. 1 to No. 7 and Comparative Copolymer] Polymerizable liquid crystalline monomer (see Table 1 below) and 4- (6-methacryloyloxyhexyloxy) benzoic acid (hereinafter , Also referred to as "MAHBA") in 200m
l and dissolve benzoyl peroxide in 3 mol
%, And the mixture was reacted at 65 ° C. for 8 hours after purging with argon. After the reaction, the resulting reaction solution was added to 2000 ml of methanol, and the resulting white precipitate was collected by filtration. The obtained copolymer was measured for yield, yield, and number average molecular weight (Mn) and weight average molecular weight / number average molecular weight (Mw / Mn) in terms of monodisperse polystyrene (GPC: tetrahydrofuran). The results are shown in Table 1 below. Further, the phase transition temperature of the obtained copolymer was measured, and the results are shown in the following [Table 2].

Synthesis of Copolymer No. 8 Copolymer No. 8 was used except that MAHBA was replaced with methacrylic acid.
Copolymer No. 8 was obtained in the same manner as in o.3. The yield, yield, Mn and Mn / Mw of the obtained copolymer were measured, and the results are shown in Table 1 below. Further, the phase transition temperature of the obtained copolymer was measured, and the results are shown in the following [Table 2].

[0054]

[Table 1]

[0055]

[Table 2]

Examples 1-1 to 1-8 and Comparative Example 1-1 The amount of 1,3 g of the copolymer obtained in the above synthesis example and the amount of the carboxylic acid group which reacts with the carboxylic acid group of the copolymer without excess or shortage was 1. 3
-Phenylenebisoxazoline with cyclohexanone / methyl ethyl ketone = 8/2 (wt / wt) (hereinafter, referred to as
(CH / MEK) to obtain a coating solution. The obtained coating solution was applied to a glass substrate with a spin coater and thermally cured at 150 ° C. for 1 hour. Each of the obtained cured films retained birefringence, which is an optical property. One drop of chloroform or CH / MEK was dropped onto the obtained cured film, and the solvent resistance was evaluated by visually observing the change such as swelling of the film. If no change was observed,
Those showing slight swelling were evaluated as Δ, and those showing obvious changes such as swelling were evaluated as ×. The results are shown in Table 3 below.

Comparative Example 1-2 A film was obtained and evaluated in the same manner as in Example 1-1 except that the oxazoline compound was not used. The results are shown in Table 3 below.

[0058]

[Table 3]

From the above results, the thermosetting composition of the present invention comprising the specific liquid crystalline polymer having a carboxylic acid group [the component (A)] and the specific oxazoline compound [the component (B)] (Example) It is clear that 1-1 to 1-8) have excellent solubility in a solvent and can provide an excellent cured film after curing.

[0060]

The thermosetting composition of the present invention has excellent solubility in a solvent, and the cured film after curing has excellent solvent resistance. Therefore, according to the thermosetting composition of the present invention, a polymer liquid crystal film having excellent solvent resistance can be provided.

Claims (3)

[Claims] 1. A thermosetting composition comprising the following components (A) and (B). (A); a polymerizable liquid crystal monomer having no carboxylic acid group (a), a polymerizable liquid crystal monomer having a carboxylic acid group (b), and a carboxylic acid group At least 2 selected from the group consisting of non-liquid crystalline polymerizable monomers (c)
A liquid crystalline polymer having a carboxylic acid group, obtained by copolymerizing various kinds of monomers. (B): a compound having two or more oxazoline groups in the molecule. 2. The polymerizable liquid crystalline monomer (a) or (b) is a compound represented by the following general formula (I) (wherein, in the case of (a), R ² is The thermosetting composition according to claim 1, wherein R ² is a group other than a carboxyl group, and in the case of (b), R ² is a carboxyl group. Embedded image 3. The polymerizable liquid crystalline monomer (a) and / or
Or the sum of the contents of the structural unit portion consisting of (b) is
The thermosetting composition according to claim 1, wherein the content is 30% by weight or more in the liquid crystalline polymer as the component (A).