JP2007079365A - Thermosetting resin composition for color filter protecting film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosetting resin composition for a color filter protecting film, the composition having favorable curing property and storage stability, basic performances such as heat resistance, solvent resistance, heat-resistant coloring property and adhesion property of a cured film obtained after curing, and having excellent flattening property, and to provide a color filter having a layer of the resin cured product. <P>SOLUTION: The thermosetting resin composition for a color filter protecting film comprises an oxetanyl group-containing polymer (A) having a weight average molecular weight (Mw) of 3,000 to 300,000 and an oxetane equivalent of 140 to 1,000 g/mol and having a specified structural unit, and a polyvalent carboxylic acid derivative (B) having a carboxyl group of a polyvalent carboxylic acid (b1) being potentialized with a vinylether compound (b2), and contains the component (A) by 20 to 80 wt.% and the component (B) by 20 to 80 wt.% with respect to the solid content. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thermosetting resin composition for a color filter protective film used in a liquid crystal display device (LCD), a solid-state imaging device (CCD, etc.), an electroluminescence device (ELD), etc., and the thermosetting resin composition. It relates to the color filter used.

Conventionally, color filters used in liquid crystal display devices (LCDs), solid-state imaging devices (CCDs, etc.), electroluminescence devices (ELDs), etc. are bleed for the purpose of flattening the irregularities of RGB resists, or more bleed than RGB resists. For the purpose of protecting the liquid crystal and the like from the ionic substance that goes out, a layer called a protective film is provided between the RGB resist and the liquid crystal alignment film or the ITO layer. This protective film is required to have performance such as transparency, chemical resistance, heat resistance, adhesion, ITO forming process resistance, and flatness.
In recent years, black matrix (hereinafter referred to as BM), which is a constituent material of color filters, has been replaced by resin BM from chromium BM due to diversification of LCD display modes and environmental problems. The conventional chromium BM was formed on the substrate with a film thickness of 0.15 to 0.20 μm, whereas the resin BM had a film with a thickness of 1.0 to 1.5 μm in order to obtain a sufficient optical density (OD value). Thickness is required. Due to this film thickness, a large step is formed at the end of the RGB pixel overlapping the resin BM. In high-quality LCDs, such as the IPS (In Plane Switching) mode, where the gap (liquid crystal layer thickness) accuracy between the color filter and the TFT array substrate is required, this step becomes a problem. In particular, there is an increasing demand for flatness.
Many studies have been made so far in order to satisfy the above performance including flatness.

Patent Document 1 discloses a thermosetting resin composition for a color filter protective film having improved storage stability by using a polymer having two or more (meth) acrylates and glycidyl groups and a carboxylic acid derivative. .
In Patent Document 2, an acrylic copolymer containing an epoxy group, a cardo epoxy resin, an alicyclic epoxy resin having two or more epoxy groups, a low molecular weight epoxy compound as an essential component, and a color filter with improved flatness A resin composition for a protective film is disclosed.
Patent Document 3 discloses a thermosetting resin composition for a color filter protective film having an oxetanyl group-containing compound, a cationic polymerization initiator, and an organoalkoxide silane as essential components and improved flatness and storage stability. ing.
In Patent Document 4, there is provided a thermosetting resin composition for a color filter protective film, in which an acrylic copolymer having a hydroxyl group, a carboxyl group, an epoxy group, and an oxetanyl group is an essential component and adhesion, transparency, and hardness are improved. It is disclosed.
Patent Document 5 discloses a thermosetting resin composition having improved adhesion, transparency, and heat resistance by using a oxetanyl group-containing methacrylate, a compound having two or more carboxyl groups, and a fourth onium salt. ing.

On the other hand, in recent years, the required performance of liquid crystal display devices has been advanced with the progress of the technology, and higher performance has been strongly demanded for materials. As liquid crystal display devices have higher image quality and higher definition, color filters with narrower pixel widths have been developed.
For this reason, higher flatness is required for the color filter protective film. For example, the step reduction ratio after providing the color filter protective film with a coating film thickness of 70% with respect to the initial step is 80%. It is desirable that it is the above. However, none of the above disclosed techniques has achieved such high flatness.

JP 2001-350010 A JP 2004-069930 A JP 2001-098048 A JP 2000-239497 A Japanese Patent Laid-Open No. 11-236438

The first object of the present invention has good curability and storage stability, and has basic properties such as heat resistance, solvent resistance, heat resistance coloring, and adhesion of a cured film obtained after curing. Furthermore, it is providing the thermosetting resin composition for color filter protective films which has the outstanding planarization ability.
In addition, the second object of the present invention is to provide a color filter having a layer of a cured resin product having excellent flatness while having basic performance such as heat resistance, solvent resistance, heat resistance coloring property, and adhesion. There is to do.

As a result of intensive studies to solve the above-mentioned problems, the present inventors formulated a specific amount of an oxetanyl group-containing polymer (A) having a specific structure and a latent polyvalent carboxylic acid derivative (B). The knowledge which the thermosetting resin composition for color filter protective films solved the said subject was acquired, and it came to complete this invention.
That is, the present invention includes the following [1] to [3].
[1] Oxetanyl group-containing weight having a structural unit represented by the following formula (1) having a weight average molecular weight (Mw) of 3,000 to 300,000 and an oxetane equivalent of 140 to 1,000 g / mol. The compound (A) and the polyvalent carboxylic acid derivative (B) in which the carboxyl group of the polyvalent carboxylic acid (b1) is latentized by the vinyl ether compound (b2), and the component (A) A thermosetting resin composition for a color filter protective film, comprising 20 to 80% by weight and 20 to 80% by weight of the component (B).

(In the formula, R ¹ and R ² are a hydrogen atom or a linear or branched hydrocarbon group having 1 to 5 carbon atoms, R ³ is a hydrogen atom or a methyl group, and R ⁴ is 1 to 5 carbon atoms. Represents a hydrocarbon group.)
[2] The thermosetting resin composition for a color filter protective film as described in [1] above, further comprising 60% by weight or less of polyvalent oxetanyl ether (C) based on the solid content .
[3] A color filter having a layer of a cured resin obtained by curing the thermosetting resin composition according to [1] or [2].

The thermosetting resin composition for the color filter protective film of the present invention has good curability and storage stability, and the cured film obtained after curing has heat resistance, solvent resistance, heat resistance coloring property, In addition to having basic performance such as adhesion, it has excellent planarization ability.
In addition, according to the present invention, a color filter having a layer of a cured resin product having excellent flatness can be obtained while having basic performance such as heat resistance, solvent resistance, heat resistance colorability, and adhesion. .

The present invention is described in detail below.
In the present invention, the color filter protective film widely means a protective film used for a display device having a color filter and a solid-state image sensor, and more specifically, a liquid crystal display device (LCD), a solid-state image sensor (CCD, etc.). , Color filter parts used in electroluminescent devices (ELD), etc., light emitting or receiving element parts, electrode parts, etc., which are in direct contact with the protective film to protect them, or these parts indirectly through other materials It means a protective film to protect.
Moreover, in order to specify a compounding ratio in this invention, solid content means the sum total of all the compounding components except a solvent, and liquid components, such as an epoxy group containing compound, are also contained in solid content.
1. Thermosetting resin composition for color filter protective film <Oxetanyl group-containing polymer (A)>
The thermosetting resin composition for a color filter protective film of the present invention has a weight average molecular weight (Mw) of 3,000 to 300,000 and an oxetane equivalent of 140 to 1,000 g / mol. An oxetanyl group-containing polymer (A) having the structural unit represented by (1), a polyvalent carboxylic acid derivative (B) in which the carboxyl group of the polyvalent carboxylic acid (b1) is latentized by a vinyl ether compound (b2), and The component (A) is contained in an amount of 20 to 80% by weight and the component (B) is contained in an amount of 20 to 80% by weight based on the solid content.

(In the formula, R ¹ and R ² are a hydrogen atom or a linear or branched hydrocarbon group having 1 to 5 carbon atoms, R ³ is a hydrogen atom or a methyl group, and R ⁴ is 1 to 5 carbon atoms. Represents a hydrocarbon group.)

The oxetanyl group-containing polymer (A) used in the present invention can be obtained by polymerizing an oxetanyl group-containing monomer alone or by copolymerizing an oxetanyl group-containing monomer and another monomer. The molecular form may be linear or may have a branched structure, and may be any form such as a random copolymer, a block copolymer, and a graft copolymer.
The oxetanyl group-containing polymer (A) in the thermosetting resin composition for a color filter protective film of the present invention can be polymerized by a conventional polymerization method. That is, the polymerization method is not particularly limited, and a polymerization method such as radical polymerization or ionic polymerization can be employed. More specifically, in the presence of a polymerization initiator, a bulk polymerization method, a solution polymerization method, a suspension polymerization method, A polymerization method such as an emulsion polymerization method can be employed. Depending on the polymerization method, a large amount of monomer may remain, but if this monomer affects the physical properties of the protective film after coating and curing, the monomer can be removed by vacuum distillation or reprecipitation formation. Also good.
The oxetanyl group-containing polymer (A) in the thermosetting resin composition for a color filter protective film of the present invention may further have structural units represented by the following formulas (2) to (4). good.

(In the formula, R ⁵ is a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, R ⁶ is an alkyl group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms in the main ring, and aromatic. Group hydrocarbon group, aryloxy group, or polyalkylene glycol residue.)

(In the formula, R ⁷ is a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, R ⁸ is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group, a hydroxyalkyl group, a hydroxy group, a siloxyalkyl group, Or an aromatic hydrocarbon group.)

(In the formula, R ⁹ is a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, or an aromatic hydrocarbon group.)
The structural unit represented by the formula (1) is derived from an oxetanyl group-containing monomer represented by the following formula (5).

(Wherein R ¹ , R ² , R ³ and R ⁴ are the same as those in formula (1))
In the formula (5), R ¹ is preferably a methyl group or an ethyl group, R ² is preferably a hydrogen atom or a methyl group, and R ⁴ is preferably a methylene group. In the formula (5), (3-methyl-3-oxetanyl) methyl (meth) acrylate is preferable from the viewpoint of availability. Here, the (meth) acrylate in the present invention means that either acrylate or methacrylate may be used.
The structural units represented by the formulas (2) to (4) are derived from monomers represented by the following formulas (6) to (8).

(Wherein R ⁵ and R ⁶ are the same as those in formula (2))

In the formula (6), the alicyclic hydrocarbon group having 3 to 12 carbon atoms constituting the main ring represented by R ⁶ has an additional structure such as an intracyclic double bond, a side chain of a hydrocarbon group, a spiro It may contain a ring side chain, an intra-ring bridged hydrocarbon group, and the like.
In the formula (6), R ⁵ is preferably hydrogen or a methyl group, and R ⁶ is preferably an alkyl group having 1 to 6 carbon atoms, a cyclohexyl group, or a dicyclopentanyl group.

(Wherein R ⁷ and R ⁸ are the same as those in formula (3))
In the above formula (7), R ⁷ is preferably hydrogen or a methyl group, and R ⁸ is preferably an alkyl group having 1 to 6 carbon atoms or a phenyl group.

(Wherein R ⁹ is the same as in formula (4))
In the formula (8), R ⁹ is preferably a cyclohexyl group or a phenyl group.
In the thermosetting resin composition for a color filter protective film of the present invention, the oxetanyl group-containing polymer (A) is blended in a range where the oxetane equivalent is 140 to 1,000 g / mol. Moreover, it has 10-100 weight% in an oxetanyl group containing polymer (A) among oxetanyl group containing structural units represented by the said Formula (1), Preferably it has 25-70 weight%. In the case where the oxetanyl group-containing structural unit represented by the formula (1) is less than 10% by weight or the oxetane equivalent is less than 140 g / mol in the oxetanyl group-containing polymer (A), a desirable crosslinking density May not be obtained and the physical properties of the protective film may deteriorate. In addition, when the oxetane equivalent exceeds 1,000 g / mol, it is not possible to achieve flattening of the cured resin, which is the effect of the present application.

  The weight average molecular weight (Mw) of the oxetanyl group-containing polymer (A) in the thermosetting resin composition for a color filter protective film of the present invention is 3,000 to 300,000, preferably 3,000 to 30. , 000. When the weight average molecular weight (Mw) is less than 3,000, a decrease in the hardness of the protective film is observed, and when it exceeds 300,000, the flatness after coating and curing may be deteriorated. In addition, the weight average molecular weight (Mw) of an oxetanyl group containing polymer (A) is a weight average molecular weight of polystyrene conversion by a gel permeation chromatography (GPC) method.

Moreover, the oxetane equivalent of the oxetanyl group-containing polymer (A) in the thermosetting resin composition for a color filter protective film of the present invention is 140 to 1,000 g / mol, preferably 200 to 550 g / mol. . When the oxetane equivalent is less than 140 g / mol, the protective film after coating and curing tends to lose toughness, and when it exceeds 1,000 g / mol, the hardness of the cured film may be lowered. Furthermore, in the case of an application that requires high adhesion, the protective film is required to have toughness, and is preferably 250 to 550 g / mol. When the oxetane equivalent of the oxetanyl group-containing polymer (A) is 250 g / mol or less, the toughness is lowered, and there is a high possibility of edge breakage occurring in the adhesion test. The oxetane equivalent in this case refers to the equivalent of the oxetanyl group of the resin, and is measured according to JIS K7236: 2001 “How to Determine Epoxy Equivalent of Epoxy Resin”.
In the thermosetting resin composition for a color filter protective film of the present invention, the oxetanyl group-containing polymer (A) may be a mixture of two or more types having different molecular weights and comonomer types.

<Polyvalent carboxylic acid derivative (B)>
The polyvalent carboxylic acid derivative (B) in the thermosetting resin composition for a color filter protective film according to the present invention is a vinyl ether compound in which the carboxyl group of the polyvalent carboxylic acid compound (b1) is represented by the following formula (9) ( b2) A compound made latent (hereinafter referred to as blocking) by a (vinyl group and ether group-containing compound).
In the thermosetting resin composition of the present invention, the polyvalent carboxylic acid derivative (B) is soluble by blocking the carboxyl group of the poorly soluble polyvalent carboxylic acid compound (b1) used as a curing agent. Used in the form of a high polyvalent carboxylic acid derivative (B). This polyvalent carboxylic acid derivative (B) has a significantly improved fluidity compared to a non-blocked polyvalent carboxylic acid compound. Furthermore, the polyvalent carboxylic acid derivative (B) does not regenerate the carboxyl group unless heated to a predetermined temperature or higher according to the compound. Accordingly, the thermosetting resin composition containing the polyvalent carboxylic acid derivative (B) has good storage stability and also has fluidity that contributes to the flatness of the protective film when applied to a color filter. Since the time to be maintained becomes long and the action of flattening the film surface is excellent, the flatness of the protective film is remarkably improved.

  Oxetanyl groups are less reactive than epoxy groups, so when carboxylic acids and acid anhydrides are used as curing agents, the reaction rate is too slow for a non-catalytic system or a basic catalyst system that is usually used. Not suitable for use. Therefore, in the curable composition containing an oxetanyl group, an acid catalyst such as an onium salt is conventionally used. When an acid catalyst is used, the reaction with a carboxylic acid or an acid anhydride is completed. If it tries to do so, the polymerization reaction of oxetanyl groups having a higher reaction speed than that occurs preferentially, and the flattening effect due to the extension of the fluidity retention time, which is the effect of the present application, cannot be obtained.

(Here, R ¹⁰ is a hydrocarbon group having 1 to ¹⁰ carbon atoms.)
More specifically, the polyvalent carboxylic acid derivative (B) in which the carboxyl group of the polyvalent carboxylic acid (b1) is blocked by the vinyl ether compound (b2) has two functional groups represented by the formula (10). It is a compound having the above.

(Where R ¹⁰ is the same as equation (9))
Specific examples of the vinyl ether compound (b2) represented by the formula (9) include, for example, methyl vinyl ether, ethyl vinyl ether, i-propyl vinyl ether, n-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether. And aliphatic vinyl ether compounds such as 2-ethylhexyl vinyl ether and cyclohexyl vinyl ether. Among them, n-propyl vinyl ether and i-butyl vinyl ether are preferable because they are available and the curing temperature is compatible with the process of the protective film.
A vinyl ether compound (b2) can be used individually by 1 type or in combination of 2 or more types.

The polyvalent carboxylic acid (b1) used in the polyvalent carboxylic acid derivative (B) in the thermosetting resin composition for the color filter protective film of the present invention is a 2 to 8 valent carboxylic acid having 4 to 20 carbon atoms. Preferably there is. From the viewpoint of fluidity that contributes to availability and flatness, preferred examples include itaconic acid, maleic acid, succinic acid, citraconic acid, tetrahydrophthalic acid, hexahydrophthalic acid, methyltetrahydrophthalic acid, cyclopentanetetracarboxylic acid, and cyclohexane. Aliphatic polycarboxylic acids such as tricarboxylic acids; aromatic polycarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, merit acid, trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, and hydrides thereof. Can be mentioned. Among these carboxylic acids, trivalent or higher carboxylic acids are preferable from the viewpoint of hardness.
As the polyvalent carboxylic acid derivative (B), a half ester obtained by a reaction between an alcohol compound and an acid anhydride can also be used.
Examples of the alcohol compound used in this reaction include monovalent alcohol compounds such as ethanol, propanol, hexanol, octanol, i-propyl alcohol; ethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, cyclohexane Preferred examples include divalent alcohol compounds such as diols; trivalent alcohol compounds such as glycerin, pentanetriol, hexanetriol, cyclohexanetriol, benzenetriol, and trimethylolpropane; and tetravalent alcohol compounds such as pentaerythritol. More preferably, hexanol, i-propyl alcohol, 1,2-propylene glycol, 1,3-propylene glycol, 1,6-hexanediol, Serine, trimethylolpropane, pentaerythritol.
Specific examples of acid anhydrides used in this reaction include phthalic anhydride, 1,2-cyclohexanedicarboxylic acid anhydride, 1,3,4-tricarboxylic acid-3,4-anhydride ( Hereinafter, it is referred to as trimellitic anhydride), 1,3,4-cyclohexanetricarboxylic acid-3,4-anhydride, and methylhexahydrophthalic anhydride. In addition, in the above half ester bodies, since a protective film with high crosslink density and high adhesion can be obtained, a polyhydric alcohol having 3 to 6 carbon atoms and divalent or higher polyhydric alcohol and trimellitic anhydride or methylhexahydroanhydride What is obtained by a combination with phthalic acid is preferably exemplified as (b1). Among them, methylhexahydrophthalic anhydride is preferably selected from the viewpoints of transparency and storage stability.

The polyvalent carboxylic acid derivative (B) in the thermosetting resin composition for a color filter protective film of the present invention comprises the polyvalent carboxylic acid (b1) and the vinyl ether compound (b2) at room temperature to 150 ° C. It can obtain by making it react at the temperature of the range of these. Since the blocking reaction is an equilibrium reaction, if the vinyl ether compound (b2) is used slightly more than the polyvalent carboxylic acid (b1), the reaction is promoted and the yield can be improved. Specifically, the molar equivalent ratio [the molar equivalent ratio of (vinyl group / carboxyl group)] of the vinyl group of the vinyl ether compound (b2) to the carboxyl group of the polyvalent carboxylic acid (b1) is 1/1 to 2/1. It is desirable that When this molar equivalent ratio exceeds 2/1, the reaction temperature cannot be increased, and the reaction rate may be extremely low. When the molar equivalent ratio is less than 1/1, a carboxyl group that is not blocked remains, so that the fluidity is lowered and the effect of the present invention cannot be obtained.
When the blocking reaction is performed, an acid catalyst can be used for the purpose of accelerating the reaction. Examples of such a catalyst include an acidic phosphate compound represented by the following formula (11).

(In the formula, R ¹¹ is an alkyl group having 3 to 10 carbon atoms, a cycloalkyl group, or an aryl group, and m is 1 or 2.)
Moreover, when performing blocking reaction, you may use an organic solvent for the purpose of making a reaction system uniform and making reaction easy. Examples of organic solvents used here include aromatic hydrocarbons, ethers, esters and ether esters, ketones, phosphate esters, nitriles, aprotic polar solvents, propylene glycol alkyl ether acetates, and the like. Is mentioned. More preferred are cyclohexanone and propylene glycol monomethyl ether acetate.
The said organic solvent can be used individually by 1 type or in combination of 2 or more types. Although the usage-amount of the said organic solvent is not specifically limited, It is 5-95 mass parts normally with respect to 100 mass parts of reaction raw materials, Preferably, it is 20-80 mass parts.

<Polyvalent oxetanyl ether (C)>
In the thermosetting resin composition for a color filter protective film of the present invention, the step reduction ratio of the protective film is further improved by further blending polyvalent oxetanyl ether (C). In the present invention, the polyvalent oxetanyl ether (C) is a 3-alkyl-3-hydroxymethyloxetane having an aliphatic alkyl group optionally having 1 to 4 carbon atoms, and 2 to 8 valences. This refers to an ether condensate of an alkyl polyol compound having 1 to 18 aliphatic or aromatic alkyl groups and 3-alkyl-3-hydroxymethyloxetane itself.

More specifically, examples of the polyvalent oxetanyl ether (C) used in the present invention include bis ((3-ethyl-3-oxetanyl) methyl) ether, 1,4-bis (((3-ethyl-3- Oxetanyl) methoxy) methyl) benzene, 1,4-bis (((3-ethyl-3-oxetanyl) methoxy) methyl) benzene, 4,4′-bis (((3-ethyl-3-oxetanyl) methoxy) methyl ) Biphenyl, 3,3 ′, 5,5′-methyl-4,4′-bis (((3-ethyl-3-oxetanyl) methoxy) methyl) biphenyl, 1,4-bis ((3-ethyl-3 -Oxetanyl) methoxy) benzene, 4,4'-bis ((3-ethyl-3-oxetanyl) methoxy) biphenyl, 3,3 ', 5,5'-methyl-4,4'-bis ((3-ethyl -3-Oxe Yl) methyl) biphenyl, and the like.
Among these polyvalent oxetanyl ethers (C), 1,4-bis (((3-ethyl-3-oxetanyl) methoxy) methyl) benzene and bis (1-ethyl (3-oxetanyl)) methyl ether are From the viewpoint of physical properties of a protective film obtained by curing, such as light transmittance.
The polyvalent oxetanyl ether (C) may be used alone or in combination of two or more.

<Combination ratio of the above components (A), (B), (C)>
The thermosetting resin composition for a color filter protective film of the present invention may be optionally diluted with a solvent because the optimum viscosity differs depending on the type of coating process. Furthermore, the thermosetting resin composition for a color filter protective film of the present invention may contain any amount of fillers and additives as described below.
The thermosetting resin composition for a color filter protective film of the present invention comprises 20 to 80% by weight of the oxetanyl group-containing polymer (A) and 20 to 80% of the polyvalent carboxylic acid derivative (B) based on the solid content. It is contained by weight.
The blending ratio of the oxetanyl group-containing polymer (A) component is preferably 25 to 70% by weight, more preferably 30 to 60% by weight. When the blending ratio of the oxetanyl group-containing polymer (A) is less than 20% by weight, performance such as adhesion of the protective film is deteriorated, and when it exceeds 80% by weight, the basic requirement of the protective film cannot be achieved.

The blending ratio of the polycarboxylic acid derivative (B) is 20 to 80% by weight, preferably 30 to 70% by weight. When the blending ratio of the polyvalent carboxylic acid derivative (B) is less than 20% by weight, it becomes difficult to obtain the effect of the present invention. When the blending ratio exceeds 80% by weight, the carboxylic acid becomes excessive and the transparency is lowered.
The blending ratio of the polyvalent oxetanyl ether (C) is less than 60% by weight, preferably 1 to 50% by weight, more preferably 3 to 20% by weight, and further preferably 5 to 10% by weight. When there are too many compounding ratios of polyvalent oxetanyl ether (C), the basic performance of a protective film will be impaired.

  The ratio of the amount of the oxetanyl group-containing polymer (A), polyvalent carboxylic acid derivative (B), and polyvalent oxetanyl ether (C) is preferably in the following range. Molar concentration of carboxyl group generated after elimination (delatentization, deblocking) of vinyl ether compound of polyvalent carboxylic acid derivative (B), and oxetanyl of oxetanyl group-containing polymer (A) and polyvalent oxetanyl ether (C) The ratio (carboxyl group / oxetanyl group) to the total molar concentration of the group is 0.2 / 1 to 1.6 / 1, preferably 0.7 / 1 to 1.2 / 1, more preferably 0.8 / 1 to 1.1 / 1. If the molar concentration ratio between the carboxyl group and the oxetanyl group is less than 0.2 / 1.0, a large amount of the oxetanyl group remains after curing, so that the crosslinking density is lowered and the protective film may impair the basic performance. is there. On the other hand, if the molar concentration ratio between the carboxyl group and the oxetanyl group exceeds 1.6 / 1, the carboxyl group becomes excessive, and the physical properties of the resin are often lowered. In addition, it can react with a carboxyl group and an oxetanyl group as an additional component which is not contained in each component of (A)-(C) which is an essential component in the thermosetting resin composition for color filter protective films of this invention. What is necessary is just to calculate by adding the molar concentration of the functional group of an additional component to the molar concentration of said carboxyl group, when adding the compound containing a functional group.

  Here, the molar concentration of the carboxyl group is simply calculated from the compound structural formula (molecular weight) and the blending amount, and more precisely, JIS K 0070: 1992 “acid value, saponification value, ester value of chemical products. , Iodine value, hydroxyl value and unsaponifiable product test method ".

<Other ingredients>
<Curing accelerator>
In the thermosetting resin composition for a color filter protective film of the present invention, a curing accelerator is appropriately used as long as the colorless transparency of the cured resin obtained by curing the thermosetting resin composition of the present invention is not impaired. You can also Examples of the curing accelerator that can be added include tertiary amines such as benzyldimethylamine, tris (dimethylaminomethyl) phenol, dimethylcyclohexylamine; 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-ethyl- Imidazoles such as 4-methylimidazole and 1-benzyl-2-methylimidazole; Organophosphorus compounds such as triphenylphosphine and triphenyl phosphite; Quaternary compounds such as tetraphenylphosphonium bromide and tetra-n-butylphosphonium bromide Phosphonium salts; diazabicycloalkenes such as 1,8-diazabicyclo [5.4.0] undecene-7 and organic acid salts thereof; organometallic compounds such as zinc octylate, tin octylate, and aluminum acetylacetonate complex Class: Tetraethylan Bromide, quaternary ammonium salts such as tetrabutylammonium bromide; boron trifluoride, boron compounds such as triphenyl borate; zinc chloride, metal halides such as stannic chloride. Furthermore, high melting point dispersion type latent accelerators such as amine addition type accelerators added to epoxy resins such as high melting point imidazole compounds, dicyandiamide and amines; the surfaces of imidazole, phosphorus and phosphine accelerators are coated with a polymer Microcapsule type latent accelerators; latent curing accelerators represented by amine salt type latent curing accelerators, high temperature dissociation type latent curing accelerators such as Lewis acid salts, Bronsted acid salts, etc. are also used. be able to.
The curing accelerator is preferably a halogen-free acidic curing accelerator from the viewpoint of liquid crystal non-contamination of the cured product. Furthermore, in view of the storage stability of the resin composition, among the halogen-free acidic curing accelerators, specifically, a Lewis acid salt high-temperature dissociation type latent curing accelerator is more preferable, as a commercially available product. May include Nofure LCAT-1 and Nofure LCAT-2 (both trade names, manufactured by NOF Corporation). These curing accelerators can be used singly or in appropriate combination of two or more. The said hardening accelerator is normally mix | blended in the ratio of 0.01 to 10 weight% with respect to solid content.

<Adhesion improvement aid>
When the thermosetting resin composition for the color filter protective film of the present invention requires a high degree of adhesion to the substrate, a silane coupling agent as an auxiliary for improving the adhesion, In addition, an adhesion improver such as a titanium coupling agent containing a metal soap, a zirconium coupling agent, or an aluminum chelating agent may be added. Examples of the silane coupling agent that can be added include a silane coupling agent having an epoxy group, a silane coupling agent having an amino group, a silane coupling agent having a (meth) acryloyl group, or a polymer thereof. Can be mentioned. As the titanium coupling agent and the zirconium coupling agent, a metal soap type containing a carboxylate may be used. These coupling agents can be added individually by 1 type or in combination of 2 or more types.
The silane coupling agent is usually added in an amount of 1 to 30% by weight, preferably 2 to 25% by weight, more preferably 3 to 20% by weight based on the solid content. When the silane coupling agent is less than 1% by weight, the adhesion is not sufficiently improved, and when it exceeds 30% by weight, the performance such as the hardness of the protective film is lowered. The titanium coupling agent and the zirconium coupling agent are usually 0.001 to 20% by weight, preferably 0.01 to 20% by weight, more preferably 0.1 to 20% by weight, still more preferably 0, based on the solid content. 2 to 15% by weight. If the titanium coupling agent and the zirconium coupling agent are less than 0.001% by weight, the adhesion is not sufficiently improved, and if it exceeds 20% by weight, the transparency of the protective film is impaired.

<Surfactant>
The thermosetting resin composition for the color filter protective film of the present invention has the purpose of improving the appearance of the protective film obtained by curing the thermosetting resin composition, or improves the compatibility of each component. A surfactant may be added for this purpose. Surfactant can be used individually by 1 type or in combination of 2 or more types as appropriate.
The surfactant is preferably blended in an amount of usually 0.001 to 3% by weight based on the solid content.

<Organic solvent>
In the thermosetting resin composition for a color filter protective film of the present invention, an organic solvent may be used for the purpose of adjusting viscosity and the like. Examples of organic solvents used here include aromatic hydrocarbons, ethers, esters and ether esters, ketones, phosphate esters, nitriles, aprotic polar solvents, propylene glycol alkyl ether acetates, and the like. It is done.
These organic solvents can be used alone or in combination of two or more.
Moreover, there is no restriction | limiting in particular about the usage-amount of these organic solvents, According to the predetermined film thickness, the smoothness of expression, the film-forming method, etc., arbitrary amounts can be added and the applicability | paintability can be provided.

<Epoxy group-containing compound>
The thermosetting resin composition for a color filter protective film of the present invention may contain an epoxy group-containing compound as long as flatness is not impaired. Examples of epoxy group-containing compounds include bisphenol A type epoxy resins, bisphenol F type epoxy resins, cresol novolac type epoxy resins, phenol novolac type epoxy resins, biphenyl type epoxy resins, stilbenzene type epoxy resins, hydroquinone type epoxy resins, and naphthalene skeletons. Type epoxy resin, tetraphenylolethane type epoxy resin, DPP (di-n-pentylphthalate) type epoxy resin, trishydroxyphenylmethane type epoxy resin, dicyclopentadienephenol type epoxy resin, 3,4-epoxycyclohexylmethyl-3 Alicyclic epoxy resins such as', 4'-epoxycyclohexanecarboxylate and vinylcyclohexene diepoxide, and diglycidides of bisphenol A ethylene oxide adducts Diglycidyl ether of bisphenol A propylene oxide adduct, cyclohexanedimethanol diglycidyl ether, polyglycidyl ether of aliphatic polyhydric alcohol, polyglycidyl ester of polybasic acid such as diglycidyl ester of hexahydrophthalic anhydride, butyl glycidyl Examples thereof include alkyl glycidyl ethers such as ether and lauryl glycidyl ether, glycidyl ethers having one epoxy group such as phenyl glycidyl ether and cresyl glycidyl ether. Moreover, the nuclear hydrogenated product of the said epoxy resin can also be used.
In the thermosetting resin composition for a color filter protective film of the present invention, the epoxy group-containing compound can be used alone or in combination of two or more.

<Other additives>
The thermosetting resin composition for a color filter protective film of the present invention may further contain a viscosity adjusting agent such as a thickener or thixotropic agent for the purpose of adjusting the viscosity. Further, infrared rays or ultraviolet absorbers may be added.
Further, for the purpose of adjusting the linear expansion coefficient, improving the flatness, improving the surface hardness, adjusting the viscosity, adjusting the refractive index, absorbing light of a predetermined wavelength, improving the adhesiveness, etc., the resin composition of the present invention is filled with an arbitrary amount of filler. Can be added. The filler used in this case is not particularly limited as long as it does not hinder transparency, but examples thereof include silica sol, silica gel, titanium oxide, aluminum oxide, cerium oxide, tin oxide, zinc oxide, and zirconium oxide. These fillers can be used individually by 1 type or in combination of 2 or more types as appropriate.
In addition, the thermosetting resin composition for the color filter protective film of the present invention includes aliphatic polyols such as ethylene glycol and propylene glycol, phenolic compounds, and the like, as long as the effects of the present invention are not impaired. Carbon dioxide generation inhibitor, flexibility imparting agent such as polyalkylene glycol, antioxidant, plasticizer, lubricant, surface treatment agent, flame retardant, antistatic agent, colorant, leveling agent, ion trap agent, sliding Additives such as property improvers, various rubbers, organic polymer beads, glass beads, thixotropic agents, surface tension reducing agents, antifoaming agents, light diffusing agents, antioxidants, fluorescent agents, and the like can be blended.
The additive can be used in an arbitrary amount within the range in which the effects of the present invention are not impaired. In this case, the transition metal, alkali metal, and alkaline earth metal atom is usually added to the solid content in an amount of 0.8. It is preferable not to mix 1% by weight or more.

<Method for producing resin composition>
The method of blending, stirring and dispersing the thermosetting resin composition for the color filter protective film of the present invention will be described below.
In the resin composition of the present invention, the components including the above components (A) to (C) may be blended together, or may be blended sequentially after each component is dissolved in a solvent. In addition, there are no particular restrictions on the charging order and working conditions when blending. For example, a resin composition may be prepared by dissolving all components in a solvent at the same time, and if necessary, each component is appropriately made into two or more solutions, and these solutions are used during use (at the time of application). May be mixed to prepare a resin composition.
In the thermosetting resin composition for a color filter protective film of the present invention, with regard to stirring after mixing the components including the components (A) to (C), a blade-type stirrer, a desolver, a kneader, a ball mill Stirring may be performed using a blender, a roll disperser, or the like, or each component may be mixed in a container such as a gallon bottle and then stirred by rotating the whole container with a mix rotor. Although the temperature of mixing and stirring is based also on a mixing | blending component, in order to avoid condensation and volatilization of a solvent, 10-60 degreeC is preferable normally.

  When a viscosity modifier or filler is added to the thermosetting resin composition for a color filter protective film of the present invention, dispersion using a high shear disperser such as a motor mill or a shaker may be performed. In this case, it is also possible to prepare a master batch using the components including the components (A) to (C) in the present invention in advance as a binder and mix them at the time of use. However, since the deblocking reaction proceeds with heat in the polyvalent carboxylic acid derivative (B) of the present invention, when the composition containing the polyvalent carboxylic acid derivative (B) is dispersed, it should not be heated to 80 ° C. or higher. Consideration is required.

2. Color filter The color filter of this invention has the layer of the resin cured material formed by hardening | curing the thermosetting resin composition for color filter protective films of the said invention.
The layer of the cured resin obtained by curing the thermosetting resin composition for the color filter protective film is not particularly limited to what is generally referred to as a protective film, for example, on the substrate of the color filter. It refers to a layer of cured resin formed between the formed RGB pixel and a liquid crystal alignment film, an ITO layer, a light emitter, or a light receiver. In addition, a case of a protective film that is not directly in contact with the RGB pixel but is indirectly protected through another material is also included. For example, an intermediate film used between a microlens and a color filter of a solid-state image sensor Alternatively, an intermediate film used between the color filter and the electrode is also included.

Since the color filter of the present invention has a layer of a cured resin obtained by curing the thermosetting resin composition for the color filter protective film of the present invention, heat resistance, solvent resistance, heat resistance colorability, adhesion In addition, a color filter having a layer of a cured resin with excellent flatness can be obtained.
As an example, the color filter includes a black matrix formed in a predetermined pattern on a transparent substrate, a pixel portion formed in a predetermined pattern on the black matrix, and a protective film formed so as to cover the pixel portion. Yes. A transparent electrode for driving liquid crystal may be formed on the protective film as necessary. Further, columnar spacers may be formed on the transparent electrode plate, the pixel portion, or the protective film in accordance with the region where the black matrix layer is formed.
The cured resin layer obtained by curing the thermosetting resin composition for the color filter protective film of the present invention is prepared by appropriately adjusting the viscosity of the thermosetting resin composition for the color filter protective film of the present invention. First, it is applied to the surface of the color filter on which the colored layer is formed.

The method for applying the thermosetting resin composition for the color filter protective film of the present invention is not particularly limited. Examples of commonly used coating methods include spin coater coating, dip coating, and spray coater. It can apply | coat to a base material by single or a combination, such as a coating method, a roll coater coating method, a screen printing coating method, an offset printing coating method, a slit coater coating method, and a die coater coating method.
Next, after drying the obtained coating film and performing preheating (hereinafter referred to as pre-baking) as necessary, a cured resin layer is formed through main curing heating (hereinafter referred to as post-baking). In this case, 40 to 140 ° C. and 0 to 1 hour are preferable as prebaking conditions, and 150 to 280 ° C. and 0.2 to 2 hours are preferable as post baking conditions. In addition, the heating method in this case is not particularly limited, and for example, a curing apparatus such as a closed curing furnace or a tunnel furnace capable of continuous curing can be employed. The heating source is not particularly limited, and can be performed by a method such as hot air circulation, infrared heating, high frequency heating or the like.

In this invention, it is preferable that the layer of a resin cured material is 0.2-5 micrometers as a film thickness after application | coating and hardening, More preferably, it is 0.5-4 micrometers. When the film thickness after coating and curing is less than 0.2 μm, it is difficult to obtain the performance required for a protective film such as barrier properties and flatness, and when it exceeds 5 μm, the performance such as transparency may be deteriorated. Is not preferable. However, for applications where high flatness is desired, the film thickness after coating and curing may be 5 to 20 μm.
Thus, the layer of the cured resin for the color filter protective film obtained in the present invention has chemical resistance and heat resistance (heating) because the cross-linked structure consists of an ester bond with a polyvalent carboxylic acid derivative and an oxetanyl group-containing compound. The degree of film reduction and discoloration by Furthermore, since the layer of the resin cured product in this invention consists of an appropriate resin composition, it is excellent in adhesiveness.
Since the oxetanyl group is less reactive with the carboxyl group than the epoxy group, when the carboxylic acid is used as a curing agent, the thermosetting resin composition containing the oxetanyl group-containing polymer (A) is an epoxy group-containing polymer. Compared with those containing, the time until the curing reaction is completed becomes longer. As a result, the time during which fluidity contributing to the flatness of the protective film is maintained is lengthened and the film surface is further flattened, so that the flatness of the protective film for a color filter of the present invention is improved. Further, since the oxetanyl group has a smaller volume reduction amount due to the curing reaction than the epoxy group, the flatness of the protective film is further improved.

In the present invention, it is dissolved in a solvent after forming a highly soluble polyvalent carboxylic acid derivative (B) by blocking the carboxyl group of the poorly soluble polyvalent carboxylic acid (b1) used as a curing agent, Used in a dispersed manner. This polyvalent carboxylic acid derivative (B) has a significantly improved fluidity as compared with the non-blocked polyvalent carboxylic acid (b1). Furthermore, since the carboxyl group is not regenerated unless the polyvalent carboxylic acid derivative (B) is heated to a predetermined temperature or higher according to the compound, the time during which the fluidity of the resin composition is maintained becomes longer. The effect of flattening the surface works sufficiently. As a result, the cured film of the thermosetting resin composition for the color filter protective film in the present invention is compared with the unblocked polyvalent carboxylic acid (b1) by using the polyvalent carboxylic acid derivative (B). And has excellent flatness.
In the present invention, the polyvalent carboxylic acid in which the carboxyl group of the oxetanyl group-containing polymer (A) and the polyvalent carboxylic acid (b1) is blocked with the vinyl ether compound (b2) is added to the thermosetting resin composition for the color filter protective film. By applying the acid derivative (B) in combination, a synergistic effect regarding each flatness improving action is exhibited, and excellent flatness can be obtained. For example, with respect to a color filter having an initial level difference of 3 μm, the step reduction rate after providing the color filter protective film with a coating thickness of 2 μm can be 80% or more.

Next, the present invention will be described more specifically with reference to examples and comparative examples.
The measurement methods and evaluation methods used in the examples and comparative examples are shown below.
<Weight average molecular weight>
The weight average molecular weight (Mw) was measured by using a gel permeation chromatography device HLC-8220GPC manufactured by Tosoh Corporation, using SHODEX K-801 manufactured by Showa Denko KK as a column, THF as an eluent, and using an RI detector. Measured and calculated by polystyrene conversion.
<Solid content>
The solid content was calculated from the residual rate calculated from the weight change before and after drying after precisely weighing 1 g of the solution and drying at 170 ° C. for 1 hour in a hot air oven.
<Viscosity>
The viscosity was measured at a temperature of 20 ° C. using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd.) equipped with a circulating constant temperature water bath.

<Oxetane equivalent>
The oxetane equivalent was measured according to the method defined by JIS K7236: 2001 “How to Determine Epoxy Equivalent of Epoxy Resin”.
<Epoxy equivalent>
The epoxy equivalent was measured by a method defined by JIS K7236: 2001 “How to Determine Epoxy Equivalent of Epoxy Resin”.
<Total acid equivalent>
The total acid equivalent was measured by hydrolysis acid value measurement according to JIS K0070: 1992 “Testing method for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponified product of chemical products”.

<Pencil hardness>
JIS K5600-5-4: 1999 “Paint General Test Method-Part 5: Mechanical Properties of Coating Film—Section 4: Scratch Hardness (Pencil Method)” shows a pencil hardness of 3H or higher by the hand-scratching method. Sometimes judged good.
<Heat resistant colorability test>
The sample on which the protective film was formed was judged to be good when the protective film had a 400 nm light transmittance of 90% or more after standing at a temperature of 250 ° C. for 1 hour.
<Adhesion>
After the sample on which the protective film was formed was treated with PCT (left at 121 ° C. in an environment of 100% humidity for 8 hours), JIS K5600-5-6: 1999 “Paint General Test Method—Part 5: Coating Film Mechanical properties of section 6: Adhesiveness (cross-cut method) ”was determined to be good when there was no peeling.
<Step reduction ratio>
Stripe-shaped irregularities were produced on a glass substrate by a conventional method using a photocurable resist on a transparent glass substrate (line / space = 25 μm / 25 μm). As a result of measuring the unevenness (step) on the surface of this substrate with a fine shape measuring instrument (manufactured by Kosaka Laboratory Ltd .; trademark: Surfcoder ET400), it was 3.0 μm. (Hereinafter, this substrate is referred to as an “evaluation substrate”.)

Next, the thermosetting resin composition for the color filter protective film was filtered through a membrane filter having a pore size of 0.2 μm, and then a glass substrate (manufactured by Nippon Electric Glass Co., Ltd .; trade name: OA-) using a spin coater. 10, non-alkali glass). Thereafter, the glass substrate was dried in a clean oven at 80 ° C. for 5 minutes and then treated in a clean oven at 230 ° C. for 30 minutes to obtain a cured film. The obtained cured film was shaved so that the glass surface was exposed, and the thickness of the cured film was measured using a fine shape measuring machine. Thus, the film thickness was measured, and the rotation speed of the spin coater was adjusted so that the film thickness was 1.8 to 2.2 μm. Next, the thermosetting resin composition for the color filter protective film was filtered through a membrane filter having a pore diameter of 0.2 μm, and then a spin coater was applied to the evaluation substrate at the above rotational speed. The evaluation substrate was dried in a clean oven at 80 ° C. for 5 minutes and then treated in a clean oven at 230 ° C. for 30 minutes. The level difference of the cured film obtained using a fine shape measuring machine was measured, and the level difference reduction rate was tested. The step reduction rate is calculated from the following equation.
Step reduction ratio (%) = {(step of color filter before forming color filter protective film−step of color filter after forming color filter protective film) / step of color filter before forming color filter protective film} × 100

Polymerization example 1
<Polymerization of Oxetanyl Group-Containing Polymer (a-1)>
A 500 mL four-necked flask equipped with a thermometer, reflux condenser, stirrer, and dropping funnel was charged with 160 parts by weight of propylene glycol monomethyl ether acetate (hereinafter referred to as PMA) and heated to 80 ° C. while stirring. did. Next, “OXE-30” (; trade name) (3-methyl-3-oxetanyl) methyl methacrylate 184 parts by weight, methyl methacrylate (hereinafter referred to as MMA) 16 parts by weight, manufactured by Osaka Organic Chemical Industry Co., Ltd. at a temperature of 80 ° C. , 7 parts by weight of t-hexylperoxy 2-ethylhexanoate (peroxide-based polymerization initiator “Perhexyl O” manufactured by NOF Corporation, purity 93%, hereinafter PHO) and 33 parts by weight of PMA in advance What was mixed (dropping component) was dropped at a constant rate from a dropping funnel over 2 hours. After completion of dropping, the temperature was maintained at 80 ° C. for 7 hours, and then the reaction was terminated. Weight average molecular weight (Mw) 30,000, solid content 52%, viscosity 10 Pa · s (20 ° C.) and oxetanyl group-containing polymer solution of solution 410 g / mol oxetanyl group-containing polymer solution (oxetane group-containing polymer oxetane equivalent 210 g / mol) )

Polymerization examples 2-6
<Oxetanyl group-containing polymer (polymerization of a-2 to 4)>
In the same manner as in Polymerization Example 1, oxetanyl group-containing polymers (a-2 to 4) were obtained. Table 1 shows the charging ratio, dropping temperature, weight average molecular weight, solid content, viscosity, and oxetane equivalent of each raw material.
<Polymerization of epoxy group-containing polymer (a'-5)>
In the same manner as in Polymerization Example 1, an epoxy group-containing polymer (a′-5) was obtained. Table 1 shows the charging ratio, dropping temperature, weight average molecular weight, solid content, viscosity, and epoxy equivalent of each raw material.
<Reaction of hydrolysis condensate (a'-6)>
In a 500 mL three-necked flask equipped with a thermometer, a reflux condenser, and a stirrer, 169 parts by weight of vinyltrimethoxysilane and 210 parts by weight of propylene glycol monomethyl ether acetate were charged and stirred. Next, 62 parts by weight of distilled water and 0.02 part by weight of oxalic acid were added, and the temperature was raised to 120 ° C. The reaction was completed after stirring at 120 ° C. for 2 hours while distilling off methanol and water produced by the reaction.

The abbreviations in the table are as follows.
* 1: Cyclohexyl methacrylate
* 2: (3-Methyl-3-oxetanyl) acrylate * 3: Dicyclopentanyl methacrylate * 4: Glycidyl methacrylate

Synthesis example 1
<Synthesis of polyvalent carboxylic acid derivative (b-1)>
In a four-necked flask equipped with a thermometer, a reflux condenser, a stirrer, and a dropping funnel, 27 parts by weight of PMA, 27 parts by weight of trimellitic acid (hereinafter, TMA) manufactured by Mitsubishi Gas Chemical Co., Ltd., n-propyl vinyl ether (hereinafter, nPr-VE) 46 parts by weight was charged and heated with stirring to 70 ° C. Next, stirring was continued while maintaining the temperature, and the reaction was terminated when the acid value of the mixture became 2.0 mgKOH / g or less, and two or more blocked carboxyl groups having an acid value of 0.64 mgKOH / g in the solution were obtained. A solution of the polyvalent carboxylic acid derivative (B) having was obtained.
Synthesis Examples 2-6
<Synthesis of polyvalent carboxylic acid derivative (b-2 to 6)>
In the same manner as in Synthesis Example 1, polyvalent carboxylic acid derivatives (b-2 to 6) were obtained. Table 2 shows the charging ratio, reaction temperature, acid value, and total acid equivalent of each raw material.

* 1: Half-esterified product of pentaerythritol (PE) and trimellitic anhydride.
* 2: 1,2,4-cyclohexanetricarboxylic acid * 3: Half-esterified product of propylene glycol (hereinafter referred to as PG) and methylhexahydrophthalic anhydride (hereinafter referred to as MHHPA).
* 4: i-propyl vinyl ether * 5: adipic acid * 6: maleic acid Examples 1-7
The step reduction rate of the thermosetting resin composition for the color filter protective film, which was dissolved and mixed at the blending ratio shown in Table 3, was tested. The results are shown in Table 4.

* 1: Only solid contents of Polymerization Example 1 and Synthesis Example 1 were described. All solvents were counted in the lower column.
* 2: Epicoat 828 (product of Japan Epoxy Resin Co., Ltd., epoxy equivalent of about 190 g / mol, bisphenol A type epoxy resin)
* 3: Acrylic nonionic surfactant (product BYK-355 manufactured by Big Chemie Japan Co., Ltd.)
* 4: Reaction product of zinc octylate and N-methylmorpholine (Japanese Unexamined Patent Publication No. 2001-350010: LCAT-1, product manufactured by NOF Corporation)
* 5: 1,4-bis (((3-ethyl-3-oxetanyl) methoxy) methyl) benzene (product “Aron Oxetane OXT-121” manufactured by Toagosei Co., Ltd.)
Comparative Examples 1-4
A cured film was obtained from the solution of the thermosetting resin composition for the color filter protective film dissolved and mixed at the blending ratio shown in Table 4 by the same method as in the Examples, and the step reduction rate was tested. The results are shown in Table 5.
In addition, except the case of the comparative example 1, the surface of the obtained coating film was very smooth in all the cases of an Example and a comparative example, and the pinhole etc. were not seen at all. In the case of Comparative Example 1, the composition did not dissolve in the solvent and became non-uniform, so that film formation was impossible.

* 1: Bis ((3-ethyl-3-oxetanyl) methyl) cyclohexane-1,4-dicarboxylate * 2: Aluminum trisacetylacetonate * 3: Acrylic nonionic surfactant (manufactured by Big Chemie Japan Co., Ltd.) Product BYK-355)
* 4: LCAT-1 (Nippon Yushi Co., Ltd. product)
* 5: Fluorene bisphenol-based epoxy resin (manufactured by Nippon Steel Chemical Co., Ltd., product ESF-300, epoxy equivalent 250 g / mol, molecular weight 463) 24.4 parts by weight, 3,4-epoxycyclohexyl-3 ′, 4 '-Cyclohexanecarboxylate (Daicel Chemical Industries, Ltd. product CEL-2021P) 19.0 parts by weight, liquid trifunctional aliphatic epoxy resin (Toto Kasei Co., Ltd. product ZX1542, epoxy equivalent 125 g / mol) 8.1 Mixture of parts by weight * 6: Mixture of 16.3 parts by weight of trimellitic anhydride and 9.90 parts by weight of b-1 component * 7: Since the curing reaction takes 1 hour, the post-bake time is 1 hour. did.

* 1: ◎ indicates a light transmittance of 95% or more, and ◯ indicates 90% or more and less than 95%. * 2: A indicates that there is no peeling, and a circle indicates that there is no peeling, but chipping occurs at the time of cross-cutting.
From the results of Table 5, Examples 1 to 7 are excellent in flatness performance after satisfying the basic performance by using the resin composition of the present invention, and the effect of the present invention is satisfactory. It turns out that it is obtained.
On the other hand, in Comparative Example 1, the composition was non-uniform and film formation was impossible.
Since Comparative Example 2 uses an epoxy group-containing polymer that is different from the oxetanyl group-containing polymer (A) of the present invention, the flatness required in recent years is poor due to poor action to flatten the surface of the protective film. Could not get.
In Comparative Example 3, although the polyvalent carboxylic acid derivative (B) of the present invention was used, the blending amount in the solid content was small, and the oxetanyl group-containing polymer (A) was not used. The film has a poor effect of flattening the film surface, and the flatness required in recent years could not be obtained.
Since Comparative Examples 4 and 5 do not use the polyvalent carboxylic acid derivative (B) of the present invention, the effect of flattening the surface of the protective film is poor, and the flatness required in recent years cannot be obtained. It was.
As described above, the thermosetting resin composition for a color filter protective film of the present invention has basic performance, and the carboxyl group of the oxetanyl group-containing polymer (A) and the polyvalent carboxylic acid (b1) is a vinyl ether. It was found that by applying a combination of the polyvalent carboxylic acid derivative (B) blocked with the compound (b2), a synergistic effect relating to each flatness improving action was exhibited, and excellent flatness could be obtained. .

Claims (3)

Oxetanyl group-containing polymer having a structural unit represented by the following formula (1) having a weight average molecular weight (Mw) of 3,000 to 300,000 and an oxetane equivalent of 140 to 1,000 g / mol (A ) And the polyvalent carboxylic acid derivative (B) in which the carboxyl group of the polyvalent carboxylic acid (b1) is latentized by the vinyl ether compound (b2), A thermosetting resin composition for a color filter protective film, comprising 80% by weight and 20 to 80% by weight of the component (B).

(In the formula, R ¹ and R ² are a hydrogen atom or a linear or branched hydrocarbon group having 1 to 5 carbon atoms, R ³ is a hydrogen atom or a methyl group, and R ⁴ is 1 to 5 carbon atoms. Represents a hydrocarbon group.)   Furthermore, 60 weight% or less of polyvalent oxetanyl ether (C) is contained with respect to solid content, The thermosetting resin composition for color filter protective films of Claim 1 characterized by the above-mentioned.   A color filter having a layer of a cured resin obtained by curing the thermosetting resin composition according to claim 1.