JP2006111701A - Resin composition for overcoat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin composition for forming an overcoat which satisfies conventional requirements such as adhesiveness, visible light transparency and high surface hardness, and is also excellent in high temperature resistance, particularly in ITO vapor deposition resistance, particularly when it is used as an overcoat of a colored resin film for color filters for liquid crystal displays. <P>SOLUTION: The epoxy resin composition for an overcoat comprises a silane-modified epoxy resin (A) having an alkoxy group obtained by subjecting an epoxy resin having a hydroxy group and an alkoxysilane partial condensate to dealcoholization condensation reaction, a curing agent (B) and a curing accelerator (C). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin composition suitable for forming a protective film, and in particular, a resin that provides a film having excellent heat resistance as a protective film provided on a colored film (for example, a colored resin film) formed on the surface of a glass substrate or the like. Relates to the composition.

  A liquid crystal display element is mainly composed of a mixture of various kinds of liquid crystal materials and an alignment film for aligning them in a certain direction. A substrate, a liquid crystal element, a polarizing plate, a color filter, a transparent conductive film It becomes a liquid crystal display device by stacking layers such as. As the transparent conductive film, an Indium Tin Oxide (hereinafter referred to as ITO) layer is known. However, when the ITO layer is formed, the element surface is locally exposed to a high temperature because of sputtering. Further, the liquid crystal display element is immersed in a solvent, an acid, an alkaline solution, or the like during the manufacturing process. In order to prevent element deterioration and damage from such severe conditions, a protective film having resistance to these elements is generally formed. In addition to the above required characteristics, such a protective film has a low degree of liquid crystal contamination, smoothness, and good adhesion to the substrate forming the protective film and the layer formed on the protective film. In order not to reduce the brightness of the liquid crystal display, it is required to have high visible light transmittance, no change over time such as coloring, whitening, yellowing, and toughness that can withstand impact, strain, etc. ing. Furthermore, for the reasons of productivity and handling, high aging stability at the time of coating or during long-term storage is desired.

  Conventionally, melamine resin, polyimide resin, acrylic resin, epoxy resin, and the like have been proposed as protective film materials, but in particular, in recent years, the demand for heat resistance has increased with the formation of alignment films and higher ITO deposition temperatures. However, at present, no balanced material that satisfies all the required characteristics has been found.

  For example, melamine resin has good heat resistance, but has extremely poor adhesion to a glass substrate, and has a problem that repelling is likely to occur on the substrate or filter. While polyimide resin has high heat resistance, it has problems such as insufficient transparency and lack of storage stability of the resin, and the use of poorly soluble organic solvents may damage the color filter. . Acrylic resin is excellent in visible light transmittance but has insufficient heat resistance, and has a problem that wrinkles and cracks occur on the film surface at high temperatures. In order to solve such a problem, a composition using a transparent filler coated with an epoxy resin has been proposed, but it is insufficient in terms of filler purity and storage stability. (See Patent Document 1.)

  Moreover, although the protective film (refer patent document 2, 3) using the acrylic resin which has an epoxy group, an epoxy resin, and o-cresol novolak type hardening | curing agent is also examined, adhesiveness is inadequate, Alternatively, there is a problem that the transmittance is lowered due to yellowing, wrinkles, and cracks of the film due to heat during ITO deposition. Attempts have been made to use acid anhydrides as curing agents in order to overcome yellowing, but there are problems with storage stability in terms of reactivity and hygroscopicity, and organic materials that can be used in terms of solubility. There are problems such as the limited solvent and the safety of the solvent.

JP-A-11-315249 Japanese Patent Laid-Open No. 5-140274 Japanese Patent Laid-Open No. 5-140267

  The present invention is a composition for forming a protective film of a colored resin film for a color filter for liquid crystal display, which has high surface hardness and heat resistance, satisfies visible light transparency, and has excellent resistance especially during ITO vapor deposition at high temperatures. The purpose is to provide.

As a result of intensive research to develop a composition having the above-mentioned properties, the present inventors have used an epoxy resin having a specific structure, thereby providing a protective film having excellent ITO deposition resistance and alkali resistance. The inventors found that a composition can be obtained and completed the present invention.
That is, the present invention

(1) A silane-modified epoxy resin having an alkoxy group obtained by subjecting an epoxy resin having a hydroxyl group and an alkoxysilane partial condensate to a dealcoholization condensation reaction (A), a curing agent (B), and a curing accelerator (C). An epoxy resin composition for a protective film,
(2) The epoxy resin composition for a protective film according to the above (1), comprising a solvent (D),
(3) The epoxy resin composition for a protective film according to the above (1) or (2), wherein the epoxy resin having a hydroxyl group is a bisphenol A type epoxy resin,
(4) The epoxy resin composition for a protective film according to any one of (1) to (3), wherein the curing agent (B) is a polyhydric phenol compound having a cyclic terpene skeleton,
(5) The epoxy resin composition for a protective film according to the above (4), wherein the polyhydric phenol compound having a cyclic terpene skeleton is a compound obtained by adding two molecules of phenols to one molecule of the cyclic terpene compound.
(6) A polyhydric phenol compound having a cyclic terpene skeleton is further subjected to a condensation reaction with a compound obtained by adding two molecules of phenols to one molecule of a cyclic terpene compound in the presence of an acidic catalyst. An epoxy resin composition for a protective film according to the above (4), which is an obtained compound,
(7) The above (4) to (4), wherein the phenol skeleton of the polyhydric phenol compound having a cyclic terpene skeleton is at least one selected from the group consisting of phenol, o-cresol, 2,6-xylenol and o-allylphenol. The epoxy resin composition according to any one of (6),
(8) The epoxy resin according to any one of (1) to (7), wherein the curing accelerator (C) is 2,3-dihydro-1H-pyrrolo- [1,2-a] benzimidazole. Composition,
(9) The epoxy resin composition according to any one of (1) to (8), which is used for a protective film of a color filter,
(10) A protective film obtained by curing the epoxy resin composition according to any one of (1) to (9) above,
(11) A liquid crystal display device comprising a color filter having the protective film according to (10) above,
About.

  The epoxy resin composition for a protective film of the present invention is excellent in storage stability and workability, and a protective film obtained by curing this is excellent in transparency, heat resistance, hardness, and alkali resistance. Moreover, it has especially high ITO vapor deposition resistance. For this reason, the epoxy resin composition for a protective film of the present invention is advantageous for protecting a colored resin film, and has a great feature that the reliability can be improved particularly in a color liquid crystal display device.

  Hereinafter, the present invention will be described in detail. In the following, “%” and “part” mean “% by weight” and “part by weight”, respectively, unless otherwise specified.

  The epoxy resin (A) used in the epoxy resin composition for a protective film of the present invention is obtained by subjecting an epoxy resin and an alkoxysilane partial condensate to a dealcoholization condensation reaction by the method described in JP-A-2001-59011. A silane-modified epoxy resin having an alkoxy group obtained in this manner.

  The epoxy resin as the raw material of the epoxy resin (A) is not particularly limited as long as it has a hydroxyl group capable of condensation reaction. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy Resin, 4,4'-biphenol, tetramethylbisphenol A type epoxy resin, dimethyl bisphenol A type epoxy resin, tetramethyl bisphenol F type epoxy resin, dimethyl bisphenol F type epoxy resin, tetramethyl bisphenol S type epoxy resin, dimethyl bisphenol S Type epoxy resin and the like. These epoxy resins are commercially available as Epicoat 828 (bisphenol A type epoxy resin), Epicoat 807 (bisphenol F type epoxy resin) (both are trade names of Japan Epoxy Resin Co., Ltd.), and the like.

  The alkoxysilane partial condensate used as the raw material of the epoxy resin (A) is a condensate of hydrolyzable alkoxysilane. Examples of the hydrolyzable alkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, Tetraalkoxysilanes such as tetraisopropoxysilane and tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane Alkyltrialkoxysilanes such as n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, phenyltrimethoxy Aryltrialkoxysilanes such as silane, trialkoxy silanes having a functional group such as vinyltrimethoxysilane, dialkoxysilane such as dimethyldimethoxysilane and the like.

  Epoxy resin (A) is, for example, from Arakawa Chemical Industry Co., Ltd. Composelane series (condensation reaction product of bisphenol A type resin and methoxysilane (trade name: Composelane HBEP125), bisphenol A type resin and methoxysilane having a methyl group As a condensation reaction product (trade name: Composelane E103B)) and the like.

  In addition to the epoxy resin (A), other epoxy resins can be blended in the protective film epoxy resin composition of the present invention within a range that does not impair the object of the present invention.

  Examples of other epoxy resins that can be used include polyfunctional epoxy resins that are glycidyl etherified products of polyphenol compounds, polyfunctional epoxy resins that are glycidyl etherified products of various novolak resins, alicyclic polyfunctional epoxy resins, and aliphatic polyfunctional resins. Examples thereof include functional epoxy resins, heterocyclic polyfunctional epoxy resins, glycidyl ester polyfunctional epoxy resins, glycidyl amine polyfunctional epoxy resins, and polyfunctional epoxy resins obtained by glycidylation of halogenated phenols.

  Examples of the polyfunctional epoxy resin that is a glycidyl etherified product of a polyphenol compound include glycidyl ether of 2- (4-hydroxyphenyl) -2- [4- [1,1-bis (4-hydroxyphenyl) ethyl] phenyl] propane. Compound, 2- [4- (2,3-epoxypropoxy) phenyl] -2- [4- [1,1-bis [4- (2,3-epoxypropoxy) phenyl] ethyl] phenyl] propane, bisphenol A Bisphenol F, bisphenol S, 4,4′-biphenol, tetramethylbisphenol A, dimethyl bisphenol A, tetramethyl bisphenol F, dimethyl bisphenol F, tetramethyl bisphenol S, dimethyl bisphenol S, tetramethyl-4,4′-biphenol , Dimethyl-4 4′-biphenol, 1- (4-hydroxyphenyl) -2- [4- (1,1-bis- (4-hydroxyphenyl) ethyl) phenyl] propane, 2,2′-methylene-bis (4-methyl) -6-tert-butylphenol), 4,4'-butylidene-bis (3-methyl-6-tert-butylphenol), trishydroxyphenylmethane, resorcinol, hydroquinone, pyrogallol, phloroglicinol, phenol having a diisopropylidene skeleton And polyfunctional epoxy resins which are glycidyl etherified products of polyphenol compounds such as phenols having a fluorene skeleton such as 1,1-di-4-hydroxyphenylfluorene and phenolized polybutadiene. The polyfunctional epoxy resin is, for example, 2- [4- (2,3-epoxypropoxy) phenyl] -2- [4- [1,1-bis [4- (2,3-epoxy) from Mitsui Chemicals, Inc. Propoxy) phenyl] ethyl] phenyl] propane (trade name: VG3101L), glycidyl ether of 2- (4-hydroxyphenyl) -2- [4- [1,1-bis (4-hydroxyphenyl) ethyl] phenyl] propane It can be obtained as a compound (trade name: VG3101).

  Examples of polyfunctional epoxy resins that are glycidyl etherified products of various novolak resins include, for example, phenols, cresols, ethylphenols, butylphenols, octylphenols, bisphenols such as bisphenol A, bisphenol F and bisphenol S, and naphthols. Glycidyl etherification products of various novolac resins such as novolak resin using phenol, phenol novolak resin having xylylene skeleton, phenol novolak resin having dicyclopentadiene skeleton, phenol novolak resin having biphenyl skeleton, phenol novolak resin having fluorene skeleton, etc. Etc. The polyfunctional epoxy resin can be obtained as, for example, EOCN1020 manufactured by Nippon Kayaku Co., Ltd. as a cresol novolak resin, and Epicoat 828 manufactured by Japan Epoxy Resin Co., Ltd. as a bisphenol A type epoxy resin.

  Examples of the alicyclic polyfunctional epoxy resin include alicyclic polyfunctional epoxy resins such as cyclohexane, and specifically, Celoxide 2080, Celoxide 3000, Celoxide 2021 [(3,4-3) manufactured by Daicel Chemical Industries, Ltd. ', 4'-epoxycyclo) hexylmethyl-hexanecarboxylate], EHPE3150, and the like. Examples of the aliphatic polyfunctional epoxy resin include glycidyl etherified products of polyhydric alcohols such as 1,4-butanediol, 1,6-hexanediol, polyethylene glycol, and pentaerythritol. Examples of the heterocyclic polyfunctional epoxy resin include a heterocyclic polyfunctional epoxy resin having a heterocyclic ring such as an isocyanuric ring and a hydantoin ring, specifically, XD-1000 manufactured by Nippon Kayaku Co., Ltd. . Examples of the glycidyl ester epoxy resin include epoxy resins made of carboxylic acid esters such as hexahydrophthalic acid diglycidyl ester. Examples of the glycidylamine-based polyfunctional epoxy resin include epoxy resins obtained by glycidylating amines such as aniline and toluidine. Examples of epoxy resins obtained by glycidylation of halogenated phenols include brominated bisphenol A, brominated bisphenol F, brominated bisphenol S, brominated phenol novolac, brominated cresol novolac, chlorinated bisphenol S, and chlorinated bisphenol A. Specific examples of the brominated bisphenol S include BREN-S (trade name) manufactured by Nippon Kayaku Co., Ltd.

  Among these epoxy resins, in view of heat resistance and transparency, 2- [4- (2,3-epoxypropoxy) phenyl] -2- [4- [1,1-bis [4- (2,3 -Epoxypropoxy) phenyl] ethyl] phenyl] propane, glycidyl ether compound of 2- (4-hydroxyphenyl) -2- [4- [1,1-bis (4-hydroxyphenyl) ethyl] phenyl] propane, bisphenol A Preferred are phenol novolak resins having a fluorene skeleton, alicyclic polyfunctional epoxy resins having an aliphatic ring skeleton such as cyclohexane, and glycidyl ethers of polyhydric alcohols such as pentaerythritol.

  The amount of the epoxy resin (A) is different depending on the resin component to be combined, but the epoxy resin component (epoxy resin (A) or epoxy resin (A) and epoxy resin (A) when using other epoxy resins than (A)) The total amount of the epoxy resin other than A) and (A) is collectively referred to as an epoxy resin component. The same applies hereinafter.) In general, it is 10 to 100% by weight, preferably 25 to 100% by weight, and more preferably 40 to 100% by weight. % Is good. If it is less than 25% by weight, it may be difficult to impart ITO resistance.

  Examples of the curing agent used in the protective film epoxy resin composition of the present invention include phenolic curing agents, acid anhydride curing agents, carboxylic acid curing agents, amine curing agents, and hydrazide curing agents. From the viewpoints of stability over time, moisture resistance, and solvent solubility, phenolic curing agents (such as polyhydric phenol compounds having a cyclic terpene skeleton) are preferred. These curing agents can be used alone or in combination. When using together, it is preferable to use in the range which does not reduce physical properties, such as heat resistant yellowing resistance and visible-light transmittance of the hardened | cured material obtained. Phenolic curing agents generally turn yellow when exposed to high temperatures and are difficult to use for visible light transparent applications. However, yellowing at high temperatures is rare in polyhydric phenol compounds having a cyclic terpene skeleton. No.

  The polyhydric phenol compound having a cyclic terpene skeleton that can be used as a curing agent in the epoxy resin composition for a protective film of the present invention is not particularly limited as long as it is a compound having two or more cyclic terpene skeletons and phenolic hydroxyl groups in the molecule. Absent. Specifically, as described in detail in, for example, Japanese Patent No. 2572293, a cyclic terpene in which a cyclic terpene compound and a phenol are reacted and a phenol is added to one molecule of the cyclic terpene compound at a ratio of about two molecules. A polyphenol compound having a skeleton, or a compound obtained by condensing it with one or more selected from the group consisting of aldehydes and ketones in the presence of an acidic catalyst (a polyvalent compound having a high molecular weight cyclic terpene skeleton) Phenolic compounds) and the like.

  Examples of the cyclic terpene compound used as a raw material for the polyhydric phenol compound having a cyclic terpene skeleton include, for example, limonene (the following formula (1)), dipentene which is an optical isomer of limonene, and α-type pinene (the following formula (2). ), Β-type pinene (the following formula (3)), α-type terpinene (the following formula (4)), β-type terpinene (the following formula (5)), γ-type terpinene (the following formula (6)), 3, 8 type Monoterpene compounds such as methanediene (following formula (7)), 2,4-type methanediene (following formula (8)), terpinolene (following formula (9)), etc. (compound in which two isoprene units are cyclized and bonded by biosynthesis) Is mentioned.

  Examples of phenols to be added to the cyclic terpene compound are unsubstituted or substituted with alkyl groups having 1 to 3 carbon atoms, aryl groups, hydroxy groups, etc. such as phenol, o-cresol, 2,6-xylenol and o-allylphenol. Phenols produced. Among these, phenol or o-cresol is preferable, and phenol is particularly preferable.

  Examples of aldehydes or ketones used in the production of a polyhydric phenol compound having a high molecular weight cyclic terpene skeleton include, for example, formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde, hydroxybenzaldehyde, acetone, cyclohexanone, etc. -6 aldehydes which may have a substituent such as an aliphatic aldehyde or ketone of -6 or a hydroxy group.

  In the reaction of the cyclic terpene compound with phenols, solvents such as aromatic hydrocarbons, alcohols and ethers are usually used, and condensation with one or more selected from the group consisting of aldehydes and ketones In this case, hydrochloric acid, sulfuric acid, phosphoric acid, polyphosphoric acid, boron trifluoride or the like is used as an acidic catalyst.

  The polyhydric phenol compound having a cyclic terpene skeleton thus obtained is presumed to be a mixture of compounds of the following formulas (I) and (II), taking as an example a compound obtained by reacting limonene and phenol.

  The polyhydric phenol compound having a cyclic terpene skeleton is easily available from the market as a phenol resin having a novolak terpene skeleton (trade name: EpiCure MP402FPY, manufactured by Japan Epoxy Resin Co., Ltd.).

  Examples of the acid anhydride curing agent include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol trimellitic anhydride, biphenyltetracarboxylic anhydride, etc. Aromatic carboxylic acid anhydride, azelaic acid, sebacic acid, dodecanedioic acid and other aliphatic carboxylic acid anhydrides, tetrahydrophthalic acid anhydride, hexahydrophthalic acid anhydride, nadic acid anhydride, het acid anhydride, Examples include alicyclic carboxylic acid anhydrides such as highmic acid anhydrides.

  Examples of the carboxylic acid curing agent include aliphatic polycarboxylic acids having 2 to 22 carbon atoms such as succinic acid, adipic acid, azelaic acid, and sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, and 1,2,4-benzene. Arocyclic such as tricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, aromatic carboxylic acid such as naphthalenedi (or tetra) carboxylic acid, tetrahydrophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid Polycarboxylic acid etc. are mentioned.

  Examples of amine curing agents include aromatic amines such as diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiphenyl ether, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 1,5-diaminonaphthalene, and m-xylylenediamine. , Diamines such as ethylenediamine, diethylenediamine, isophoronediamine, aliphatic amines such as bis (4-amino-3-methyldicyclohexyl) methane and polyetherdiamine, dicyandiamide, and 1- (o-tolyl) biguanide.

  As the phenolic curing agent, in addition to the above polyhydric phenol compound having a cyclic terpene skeleton, for example, bisphenol A, bisphenol F, bisphenol S, 4,4′-biphenylphenol, tetramethylbisphenol A, dimethylbisphenol A, Tetramethylbisphenol F, dimethyl bisphenol F, tetramethyl bisphenol S, dimethyl bisphenol S, tetramethyl-4,4′-biphenol, dimethyl-4,4′-biphenylphenol, 1- (4-hydroxyphenyl) -2- [ 4- (1,1-bis- (4-hydroxyphenyl) ethyl) phenyl] propane, 2,2′-methylene-bis (4-methyl-6-tert-butylphenol), 4,4′-butylidene-bis ( 3-methyl-6-tert- Tilphenol), trishydroxyphenylmethane, resorcinol, hydroquinone, pyrogallol, phenols having a diisopropylidene skeleton, phenols having a fluorene skeleton such as 1,1-di-4-hydroxyphenylfluorene, phenolized polybutadiene, phenol, Novolak resins made from various phenols such as cresols, ethylphenols, butylphenols, octylphenols, bisphenol A, bisphenol F, bisphenol S, naphthols, phenol novolac resins having a xylylene skeleton, phenols having a dicyclopentadiene skeleton Novolak resin, phenol novolak resin having biphenyl skeleton, phenol novolak resin having fluorene skeleton, furan skeleton Various novolak resins such as phenol novolak resin having the like.

  Examples of the hydrazide-based curing agent include carbodihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, suberic acid dihydrazide, sebacic acid dihydrazide dihydradide , Hexadecanediohydrazide, terephthalic acid dihydrazide, isophthalic acid dihydrazide, 2,6-naphthoic acid dihydrazide, 4,4′-bisbenzenedihydrazide, 1,4-naphthoic acid dihydrazide, 2,6-pyridinedihydrazide, 1,4-cyclohexane Dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, iminodiacetic acid dihydrazide, N, N'-hexamethylenebissemicarbazide, itaconic acid dihydra Dihydrazide curing agent such as de, pyromellitic acid trihydrazide, ethylenediaminetetraacetic acid tetrahydrazide, polyfunctional hydrazide type curing agent such as 1,2,4-benzenetricarboxylic hydrazide.

  The amount of the curing agent used is usually 0.2 to 1.8 mol, preferably 0.4 to 1.4 mol, more preferably 0.6 to 1.2 mol, assuming that the epoxy resin component is 1 mol. is there.

  In the present invention, a curing accelerator can be used as necessary. As the curing accelerator that can be used in the present invention, an imidazole-based curing accelerator is used. In addition, compounds known as catalysts for promoting the curing of epoxy resins, such as tertiary amines and phosphines, are used. Can be used in combination.

  Examples of the imidazole curing accelerator include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, 1 -Benzyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 2,3-dihydro -1H-pyrrolo- [1,2-a] benzimidazole, 2,4-diamino-6 (2'-methylimidazole (1 ')) ethyl-s-triazine, 2,4-diamino-6 (2'- Undecylimidazole (1 ′)) ethyl-s-triazine, 2, -Diamino-6 (2'-ethyl, 4-methylimidazole (1 ')) ethyl-s-triazine, 2,4-diamino-6 (2'-methylimidazole (1')) ethyl-s-triazine isocyanuric Acid adduct, 2-methylimidazole isocyanuric acid 2: 3 adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-3,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethyl Various imidazole compounds such as imidazole or 1-cyanoethyl-2-phenyl-3,5-dicyanoethoxymethylimidazole may be mentioned.

  Usually, the usage-amount of the hardening accelerator which can be used for the epoxy resin composition for protective films of this invention is 0.1-10 parts with respect to 100 parts of epoxy resin components, However, These imidazole type hardening accelerators are used. The amount used is usually 0.1 parts or more, preferably 0.3 parts or more, more preferably 0.5 parts or more, and 7 parts or less, preferably 5 parts, relative to 100 parts of the epoxy resin component. The amount is more preferably 4 parts or less, still more preferably 3.5 parts or less. When the amount of the imidazole curing accelerator used is small, sufficient crosslinking reaction is unlikely to occur, adversely affecting the heat resistance of the protective film, and when it is too much, stability over time, yellowing resistance during curing, liquid crystal contamination resistance There is a possibility of reducing the sex.

  A solvent (D) can be used for the epoxy resin composition for protective films of this invention as needed. Solvents (D) that can be used include alcohols, glycol ethers, alkylene glycol ether acetates, aromatic hydrocarbons, ketones, esters, ethers and the like. Specifically, examples of the alcohol include methanol, ethanol, propanol, butanol and the like, and a lower alcohol having 1 to 4 carbon atoms is preferable. Examples of glycol ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, 3-methoxybutanol, 3-methyl-3-methoxybutanol, and the like. A lower ether having 1 to 4 carbon atoms of 4 alkylene glycol is preferred. Examples of the alkylene glycol ether acetates include ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, dimethyldipropylene glycol, 3-methoxybutyl acetate, 3-methyl- Examples thereof include 3-methoxybutyl acetate, ethyl ethoxypropiolate, and the like, and lower ether acetates having 1 to 4 carbon atoms of alkylene glycols having 1 to 4 carbon atoms are preferable. Examples of aromatic hydrocarbons include toluene and xylene. Examples of ketones include methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, and the like. Examples of esters include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, methyl hydroxyacetate, ethyl hydroxyacetate, hydroxyacetic acid Butyl, methyl lactate, ethyl lactate, butyl lactate, methyl 3-hydroxypropionate, ethyl 3-hydroxypropionate, propyl 3-hydroxypropionate, butyl 3-hydroxypropionate, propyl 2-hydroxy-3-methylbutanoate, methoxy Ethyl acetate, propyl methoxyacetate, methyl ethoxy acetate, ethyl ethoxy acetate, propyl ethoxy acetate, butyl ethoxy acetate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate, 2-methoxypropionate Pill, butyl 2-methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate, propyl 2-ethoxypropionate, butyl 2-ethoxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate Propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, propyl 3-ethoxypropionate, butyl 3-ethoxypropionate and the like, hydroxy group, The C1-C4 alkyl ester of the C2-C4 fatty acid which may be substituted by the C1-C4 lower alkyl group is preferable. Examples of ethers include tetrahydrofuran.

  Among these, in consideration of the solubility of the epoxy resin component, the curing agent, the curing accelerator, the reactivity with the organic solvent, the concentration change with time due to volatilization, the toxicity to the human body, etc., in the present invention, propylene glycol monomethyl ether Acetate, propylene glycol monoethyl ether acetate, dimethyl dipropylene glycol, ethylene glycol monobutyl ether acetate and the like, C2-C4 lower ether acetate of alkylene glycol, propylene glycol monomethyl ether, 3-methoxybutanol, It is preferable to use 3-methyl-3-methoxybutanol and esters.

  Moreover, there is no limitation in particular about the usage-amount of these solvents (D), What is necessary is just to adjust according to a desired film thickness, surface smoothness, the film-forming method, etc., and to provide application | coating suitability.

  The epoxy resin composition for a protective film of the present invention includes a coupling agent, a surfactant, an oxidation stabilizer, a light stabilizer, a moisture resistance improver, a thixotropy imparting agent, an antifoaming agent, and other various types as necessary. Additives such as a resin, a tackifier, an antistatic agent, a lubricant, and an ultraviolet absorber can also be blended.

  Examples of coupling agents that can be used include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 2- (3,4-epoxycyclohexyl) ethyl. Trimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltri Methoxysilane, vinyltrimethoxysilane, N- (2- (vinylbenzylamino) ethyl) 3-aminopropyltrimethoxysilane hydrochloride, 3-methacryloxypropyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloro Silane coupling agents such as propyltrimethoxysilane, isopropyl (N-ethylaminoethylamino) titanate, isopropyl triisostearoyl titanate, titanium di (dioctyl pyrophosphate) oxyacetate, tetraisopropyl di (dioctyl phosphite) titanate , Titanium-based coupling agents such as neoalkoxytri (pN- (β-aminoethyl) aminophenyl) titanate, Zr-acetylacetonate, Zr-methacrylate, Zr-propionate, neoalkoxyzirconate, neoalkoxytrisneo Decanoyl zirconate, neoalkoxytris (dodecanoyl) benzenesulfonyl zirconate, neoalkoxytris (ethylenediaminoethyl) zirconate, neoalkoxy Examples thereof include zirconium such as citris (m-aminophenyl) zirconate, ammonium zirconium carbonate, Al-acetylacetonate, Al-methacrylate, and Al-propionate, and aluminum-based coupling agents. Among these, a silane coupling agent is preferable, and a silane coupling agent having an epoxy group, for example, an epoxy silane coupling agent Silaace S-510 is more preferable. By using the coupling agent, the adhesion to the substrate is improved, and a protective film excellent in moisture resistance reliability can be obtained.

  The amount of the coupling agent used is 0.1 to 5 parts, preferably about 0.5 to 4 parts, per 100 parts of the epoxy resin component.

  In addition, a surfactant can be used in the protective film epoxy resin composition of the present invention in order to improve the coating suitability of the protective film epoxy resin composition. For example, a silicon-based surfactant or a fluorine-based surfactant is used, and it is easily available from the market as Megafac F470 (fluorine-based surfactant: manufactured by Dainippon Ink Co., Ltd.). The addition amount of the surfactant is usually 0.001 to 1.0 part, preferably 0.1 to 0.5 part, when the total amount of the epoxy resin component, the curing agent, and the curing accelerator is 100 parts.

  The epoxy resin composition for a protective film of the present invention comprises an silane-modified epoxy resin having an alkoxy group (A), a curing agent, a curing accelerator, and an epoxy resin other than the epoxy resin (A) and various additives as necessary. It can be obtained by uniformly dissolving in a solvent. This can be used as it is as a varnish. In this case, the solid content concentration is usually 10% or more, preferably 15% or more, more preferably 20% or more, and 50% or less, preferably 40% or less, more preferably about 35% or less. That's fine. Considering the efficiency of coating and the like, the composition ratio is appropriately adjusted so that the viscosity at 25 ° C. is 2 to 30 mPa · s, preferably 4 to 15 mPa · s.

  The coating film obtained by curing the epoxy resin composition for protective film of the present invention has excellent adhesion to various materials such as glass, wood, metal, plastic, etc., smoothness, yellow resistance at high temperature Because it is excellent in modification, transparency, and toughness, for example, various protective films, etc., especially in places where high visible light transmittance is required such as organic EL elements and plasma display panels (high visible light transmittance coating film) ) Is useful. In the epoxy resin composition for a protective film of the present invention, it is preferable that the transmittance when the film is formed to have a film thickness of 1 μm is 95% or more at 400 nm as satisfying high visible light transmittance. Further, the coating film obtained by curing the epoxy resin composition for a protective film of the present invention is particularly excellent in high temperature resistance during ITO film formation, so that the protective film is formed on a colored resin film such as a color filter for liquid crystal display. It is particularly useful when forming a smooth layer of a color filter for liquid crystal display.

  When the epoxy resin composition for a protective film of the present invention is used as a protective film for a color filter or the like, it is usually applied by a spin coating method. The film thickness is usually applied under the condition of 0.1 to 10 μm, preferably 0.5 to 8 μm after curing. At this time, in order to efficiently perform the coating operation, the viscosity at 25 ° C. of the composition of the present invention is 2 mPa · s or more, preferably 4 mPa · s or more, more preferably 5 mPa · s or more and 30 mPa · s or less. The amount of the solvent (D) used is usually adjusted so that it is preferably 15 mPa · s or less, more preferably 13 mPa · s or less. Drying and curing conditions after coating need to be selected optimally depending on the type of each component including the solvent used and its usage ratio, but usually after pre-baking at 70 to 100 ° C. to remove the solvent, 150 to Post bake at 250 ° C. for 10 minutes to 1.5 hours to cure. The curing temperature may not be constant, for example, curing may be performed while raising the temperature. Pre-bake solvent removal and post-bake curing can be performed using an oven, a hot plate, or the like.

  The color filter having the protective film of the present invention can be suitably used for a liquid crystal display device or the like. Since a normal liquid crystal display device is composed of a color filter part (ITO film formation and ITO patterning are performed as necessary), a liquid crystal part, a backlight part, and a polarizing film part, the color filter part of the present invention By using a color filter provided with a protective film, the liquid crystal display device of the present invention can be obtained.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example 1
The present invention having a viscosity of about 7.5 mPa · s (measured at an R-type viscometer, 10 rpm) having a composition (numerical value is “part”) shown in the column of Example 1 in Table 1 is mixed and dissolved. An epoxy resin composition for a protective film was prepared. Next, this protective layer epoxy resin composition was applied onto a 0.7 mm thick glass substrate using a spin coater so that the thickness after curing was 1.5 μm, and 100 ° C. for 2 minutes. After pre-baking under conditions, it was cured at 230 ° C. for 30 minutes to obtain a transparent protective film of the present invention. Table 2 shows the evaluation results of the protective film of the present invention (the evaluation method will be described later).

Examples 2-3 and Comparative Example 1
A protective film was prepared in the same manner as in Example 1 except that the compositions shown in the columns of Examples 2 to 3 and Comparative Examples 1 and 2 in Table 1 were used. The evaluation results are shown in Table 2.

Examples 4, 5, and 6
Using the epoxy resin composition for a protective film of the present invention having the composition shown in each column of Examples 1 to 3 in Table 1, a color filter finely patterned instead of a glass substrate (a colored resin film is formed on the surface of the glass substrate) Table 3 shows the results of the evaluation of the protective film obtained in the same manner as in Example 1 except that the above was used.

Table 1
Examples 1 and 4 Examples 2 and 5 Examples 3 and 6 Comparative Example 1
Epoxy resin A 197 98.5
(Pure 100) (pure 50)
Epoxy resin B 100
(Pure 50)
Epoxy resin C 50 50 100
Curing agent 12 31 32 74
Accelerator 2 2 2 2
Additive A 0.5 0.5 0.5 0.5
Additive B 1 1 1 1
Solvent 232 356 386 505

Details of each component in Table 1 are as follows.
Epoxy resin A: Condensation reaction product of bisphenol A type resin and methoxysilane (trade name: Composelan HBEP125, epoxy equivalent: about 870 g / eq, solvent: dimethyldipropylene glycol, pure content: 51%, manufactured by Arakawa Chemical Industries, Ltd. )
Epoxy resin B: Condensation reaction product of bisphenol A type resin and methoxysilane having a methyl group (trade name: Composelane E103B, epoxy equivalent: about 700 g / eq, solvent: dimethyldipropylene glycol, pure content: 50%, Arakawa Chemical Manufactured by Kogyo Corporation)
Epoxy resin C: glycidyl ether compound of 2- (4-hydroxyphenyl) -2- [4- [1,1-bis (4-hydroxyphenyl) ethyl] phenyl] propane (trade name: VG3101, epoxy equivalent: about 211 g / Eq, obtained by concentrating from Mitsui Chemicals, Inc.)
Curing agent: Phenolic resin having a novolac terpene skeleton (hydroxyl equivalent: 174 g / eq, trade name: EpiCure MP402FPY, manufactured by Japan Epoxy Resins Co., Ltd.)
Accelerator: 2,3-dihydro-1H-pyrrolo- [1,2-a] benzimidazole (trade name Curesol TBZ, manufactured by Shikoku Kasei Co., Ltd.)
Additive A: Fluorosurfactant Megafac F470 (Dainippon Ink Co., Ltd.)
Additive B: Epoxysilane coupling agent Silaace S-510 (manufactured by Chisso Corporation)
Solvent: Propylene glycol monomethyl ether acetate

Table 2
Example Comparative Example
1 2 3 4 5 6 1
ITO test ○ ○ ○ ○ ○ ○ ×
Transparency ○ ○ ○ ― ― ― ○ ○
Heat resistance ○ ○ ○ ― ― ― ○ ○
Hardness (Hv) 650 534 510 ― ― ― 430
Alkali resistance ○ ○ ○ ○ ○ ○ ○

In Table 2, the evaluation methods and judgment criteria are as follows.
1. The test conditions of the ITO test examples 1 to 6 and the comparative example 1 were observed when the ITO film was sputtered so that the ITO film thickness was 2500 mm and the sheet resistance value was 10 Ω / cm ^{2 under} the condition of 240 ° C. A case where there was no crack was indicated as ◯, a portion where cracks were generated, and a case where cracks were generated.
2. Transparency Examples 1 to 3 and Comparative Example 1 were measured with a spectrophotometer, and the transmittance at 400 nm when converted to a film thickness per micrometer was 95% or more. % Is Δ, and 90% or less is ×.
3. The protective films of heat resistance test examples 1 to 3 and comparative example 1 were each left in an oven at 250 ° C. for 60 minutes, and the yellowing of the protective film was visually determined. As for the judgment criteria, compared with the coating film before being left at a high temperature, ○ was almost unchanged, Δ was slightly yellowed, and x was yellowed and unusable.
5. Hardness Surface Vickers hardness under a 2mN load of a test piece prepared using a surface tester (Fischer Scope H-100C-HCU manufactured by Fischer Instruments Co., Ltd.) to a film thickness of 1.5 μm on a glass substrate. (Hv) was measured.
6). Alkali resistance The state of the coating film after immersing the protective films of Examples 1 to 6 and Comparative Example 1 in a 5 wt% aqueous sodium hydroxide solution at 60 ° C. for 30 minutes was observed. The criteria for determination were ◯ when the surface of the coating film was observed under an optical microscope at a magnification of 1000, ◯ when there was no change in appearance, Δ when the surface was found to be rough, and X when the coating film was peeled off.

  As is clear from the results in Table 2, the protective film of the present invention has a high surface hardness and excellent transparency, heat resistance, hardness and alkali resistance, and particularly excellent ITO vapor deposition resistance at high temperatures. is doing. Therefore, in the composition of the present invention, the curing agent, particularly the curing agent that is a polyhydric phenol compound having a cyclic terpene skeleton, provides a protective film excellent in ITO deposition resistance, transparency, heat resistance, hardness, and alkali resistance. I understand that.

Claims (11)

It contains a silane-modified epoxy resin (A) having an alkoxy group obtained by subjecting an epoxy resin having a hydroxyl group and an alkoxysilane partial condensate to a dealcoholization condensation reaction, a curing agent (B), and a curing accelerator (C). An epoxy resin composition for a protective film. The solvent (D) is contained, The epoxy resin composition for protective films of Claim 1 characterized by the above-mentioned. The epoxy resin composition for a protective film according to claim 1 or 2, wherein the epoxy resin having a hydroxyl group is a bisphenol A type epoxy resin. The epoxy resin composition for a protective film according to any one of claims 1 to 3, wherein the curing agent (B) is a polyhydric phenol compound having a cyclic terpene skeleton. The epoxy resin composition for a protective film according to claim 4, wherein the polyhydric phenol compound having a cyclic terpene skeleton is a compound in which two molecules of phenols are added to one molecule of the cyclic terpene compound. A polyhydric phenol compound having a cyclic terpene skeleton was obtained by subjecting a compound obtained by adding two molecules of phenols to one molecule of a cyclic terpene compound to further condensation reaction of aldehydes and / or ketones in the presence of an acidic catalyst. The epoxy resin composition for a protective film according to claim 4, which is a compound. The phenol skeleton of the polyhydric phenol compound having a cyclic terpene skeleton is at least one selected from the group consisting of phenol, o-cresol, 2,6-xylenol and o-allylphenol. The epoxy resin composition according to one item. The epoxy resin composition according to any one of claims 1 to 7, wherein the curing accelerator (C) is 2,3-dihydro-1H-pyrrolo- [1,2-a] benzimidazole. The epoxy resin composition according to any one of claims 1 to 8, which is used for a color filter protective film. The protective film obtained by hardening the epoxy resin composition as described in any one of Claims 1 thru | or 9. A liquid crystal display device comprising a color filter having the protective film according to claim 10.