JPH09100338A - Composition for forming protective film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition which can form a protective film of a high surface evenness on a substrate even when the substrate has an uneven surface. SOLUTION: This composition for forming a protective film comprises a (co)polymer containing at least 20wt.% structural units represented by the formula and having an average molecular weight of 2,000-10,000 (in terms of the polystyrene), at least one compound selected from among polycarboxylic acid anhydrides and polycarboxylic acids and an organic solvent. In the formula, R is hydrogen or a 1-5C alkyl; and (m) is an integer of 1-8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a protective film forming composition, and more particularly to a protective film forming composition suitable for forming a protective film used in an optical device.

[0002]

2. Description of the Related Art In display elements such as liquid crystal display elements,
During the manufacturing process, a dipping treatment with a solvent, an acid or an alkaline solution or the like is performed, and when the wiring electrode layer is formed by sputtering, the surface of the element is locally exposed to a high temperature. Therefore, in order to prevent the element from being deteriorated or damaged by such treatment, a thin protective film having resistance to these treatments is provided on the surface of the element.

In such a protective film, the adhesive property is high with respect to the substrate or lower layer on which the protective film is to be formed, and the layer formed on the protective film, and the film itself is smooth and tough. That it has transparency, has high heat resistance and high light resistance, and does not cause deterioration such as coloring, yellowing, and whitening over a long period of time.
Performance such as excellent water resistance, solvent resistance, acid resistance and alkali resistance is required. As a material for forming a protective film satisfying these various properties, for example, a thermosetting composition disclosed in JP-A-60-217230 is known. In such a thermosetting composition, the protective film is formed by applying the thermosetting composition to the surface of the substrate on which the protective film is to be formed and then heat-treating the coating film to cure it. can do.

On the other hand, in the super twisted nematic (STN) type color liquid crystal display element, the uniformity of the cell gap is extremely important as compared with the twisted nematic (TN) type liquid crystal display element. Therefore, the substrate used for the STN type color liquid crystal display element is required to have a high surface flatness. This is because when a substrate having a low surface flatness is used, display unevenness occurs in the obtained liquid crystal display element.

However, for example, in a substrate on which a color filter is formed, unevenness due to the color filter is formed on the surface thereof. When a conventional thermosetting composition is used to form a protective film on the substrate on which the color filter is formed, it is difficult to obtain a protective film having a highly flat surface.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made based on the above circumstances, and its object is to provide:
It is an object of the present invention to provide a protective film-forming composition capable of forming a protective film having high surface flatness on a substrate even if the substrate has an uneven surface.

[0007]

The composition for forming a protective film of the present invention comprises (A) at least 20% by weight of a structural unit represented by the following general formula (1), and has a polystyrene equivalent weight. A polymer or copolymer having an average molecular weight of 2000 to 10,000, (B) at least one compound selected from polyvalent carboxylic acid anhydrides and polycarboxylic acids, and (C) an organic solvent. It is characterized by

[0008]

Embedded image

[In the formula, R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and m represents an integer of 1 to 8. ]

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The protective film forming composition of the present invention will be specifically described below. The composition for forming a protective film of the present invention comprises a component (A) composed of a polymer or a copolymer containing a specific structural unit in a specific ratio (hereinafter referred to as “specific polymer”), and a polyvalent compound. It comprises a component (B) consisting of at least one compound selected from a carboxylic acid anhydride or a polycarboxylic acid, and a component (C) consisting of an organic solvent.

<Component (A)> The specific polymer used as the component (A) contains a structural unit represented by the above general formula (1). In the general formula (1), m is an integer of 1 to 8, preferably 1 to 4. R is a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms. This lower alkyl group may be linear or branched and includes, for example, methyl group, ethyl group, n-propyl group, isopropyl group,
n-butyl group, isobutyl group, sec-butyl group, te
Examples thereof include rt-butyl group and n-pentyl group.

Examples of the monomer used for introducing the structural unit represented by the general formula (1) (hereinafter, also referred to as “specific monomer”) include, for example, glycidyl (meth) acrylate, α-Ethyl glycidyl acrylate, α-n-propyl glycidyl acrylate, α-n-butyl glycidyl acrylate, (meth) acrylic acid-3,4-epoxybutyl, (meth) acrylic acid-4,5-epoxypentyl , (Meth) acrylic acid-6,7-epoxyheptyl,
Examples thereof include α-ethylacrylic acid-6,7-epoxyheptyl. Of these, glycidyl (meth) acrylate is particularly preferable. These monomers can be used alone or in combination of two or more kinds.

In the specific polymer used as the component (A), the structural unit represented by the above general formula (1) is
It is required to be contained in the polymer in an amount of at least 20% by weight, preferably 30 to 90% by weight, more preferably 60 to 85% by weight.

Even if the specific polymer used as the component (A) is composed of only the structural unit represented by the general formula (1), the structural unit other than these is 80% by weight.
Below, preferably 70 to 10% by weight, more preferably 4
It may be contained in a proportion of 0 to 15% by weight.

The monomer for introducing a structural unit other than the structural unit represented by the general formula (1) (hereinafter, also referred to as "other monomer") is, for example, methyl (meth) acrylate. , (Meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
Phenyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate,
(Meth) acrylic acid dicyclopentanyloxyethyl,
Examples include ethesul of (meth) acrylic acid such as isobornyl (meth) acrylate; vinyl aromatic compounds such as styrene, α-methylstyrene, p-methylstyrene, and vinylnaphthalene. These monomers can be used alone or in combination of two or more kinds.

The specific polymer used as the component (A) has a polystyrene reduced weight average molecular weight (hereinafter, simply referred to as "weight average molecular weight" or "Mw") of 2000 to.
It is set in the range of 10,000. In particular, by using a specific polymer having a weight average molecular weight of 2000 or more and less than 5000, a protective film having extremely high surface flatness can be obtained. When a polymer having a weight average molecular weight of less than 2000 is used, it becomes difficult to form a coating film from the composition. On the other hand, the weight average molecular weight is 1000
When a polymer of more than 0 is used, it becomes difficult to obtain a protective film having high surface flatness.

The specific polymer used as the component (A) is produced, for example, by polymerizing a specific monomer, or a specific monomer and another monomer in a polymerization solvent. .

Examples of the polymerization solvent used for producing the specific polymer include alcohols such as methanol and ethanol; ethers such as tetrahydrofuran; glycol ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether. , And cellosolve esters such as methyl cellosolve acetate, and aromatic hydrocarbons, ketones, esters and the like can also be used.

As the polymerization initiator for the polymerization of the specific monomer or the specific monomer and the other monomer, those generally known as radical polymerization initiators can be used. The specific examples thereof are 2,2'-azobisisobutyronitrile and 2,2'-azobis- (2,4
-Dimethylvaleronitrile), 2,2'-azobis-
Azo compounds such as (4-methoxy-2,4-dimethylvaleronitrile); benzoyl peroxide, lauroyl peroxide, tert-butyl peroxypivalate,
Organic peroxides such as 1,1′-bis- (tert-butylperoxy) cyclohexane; and hydrogen peroxide. When a peroxide is used as the radical polymerization initiator, it may be used in combination with a reducing agent as a redox type polymerization initiator.

In the production of a specific polymer, a molecular weight regulator may be used to control the weight average molecular weight, and specific examples thereof include halogenated hydrocarbons such as chloroform and carbon tetrabromide. Mercaptans such as n-hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan and thioglycolic acid; xanthogens such as dimethylxanthogen disulfide, diisopropylxanthogen disulfide; terpinolene, α-methylstyrene dimer and the like; Can be mentioned.

Further, when a specific polymer containing the structural unit represented by the general formula (1) and a structural unit other than these is used as the component (A), the polymer is a specific unit. It may be either a random copolymer or a block copolymer of a monomer and another monomer.

<Component (B)> The polyvalent carboxylic anhydride or polycarboxylic acid used as the component (B) acts as a curing agent for the specific polymer used as the component (A).

Specific examples of the polycarboxylic acid anhydride include:
Aliphatic dicarboxylic acid anhydrides such as itaconic anhydride, succinic anhydride, citraconic anhydride, dodecenyl succinic anhydride, tricarbanilic anhydride, maleic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hymic acid anhydride; 1, Alicyclic polyvalent carboxylic acid dianhydrides such as 2,3,4-butanetetracarboxylic dianhydride and cyclopentanetetracarboxylic dianhydride; phthalic anhydride, pyromellitic dianhydride, trimellitic dianhydride, and anhydrous Examples thereof include aromatic polycarboxylic acid anhydrides such as benzophenone tetracarboxylic acid; ester group-containing acid anhydrides such as ethylene glycol bis anhydride trimellitate and glycerin tris anhydrous trimellitate. Among these, aromatic polycarboxylic acid anhydrides are particularly preferable from the viewpoint of heat resistance of the formed protective film.

Specific examples of the polycarboxylic acid include:
Aliphatic polycarboxylic acids such as succinic acid, glutaric acid, adipic acid, butanetetracarboxylic acid, maleic acid and itaconic acid; hexahydrophthalic acid, 1,2-cyclohexanedicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid Alicyclic polycarboxylic acids such as cyclopentane tetracarboxylic acid; phthalic acid, isophthalic acid, terephthalic acid,
Aromatic polycarboxylic acids such as trimellitic acid, pyromellitic acid and 1,2,5,8-naphthalenetetracarboxylic acid can be exemplified. Among these, aromatic polyvalent carboxylic acids are preferable from the viewpoint of the reactivity of the composition, the heat resistance of the formed protective film, and the like. These polyvalent carboxylic acid anhydrides or polyvalent carboxylic acids can be used alone or in combination of two or more kinds.

The proportion of component (B) used is usually 1 to 100 parts by weight, preferably 3 to 50 parts by weight, per 100 parts by weight of component (A). Use ratio of component (B) is 1
If the amount is less than parts by weight, the protective film to be formed does not have a sufficient cross-linking density, and the various resistances of the protective film may decrease. On the other hand, when the proportion of component (B) used exceeds 100 parts by weight, a large amount of unreacted component (B) remains in the formed protective film, resulting in unstable properties of the protective film. Or the adhesion of the protective film to the substrate may deteriorate.

<Component (C)> As the organic solvent which is the component (C), the above-mentioned components (A), (B) and other components described below can be uniformly dissolved, and each of these components The one that does not react with is used. Specific examples of such organic solvents include alcohols such as methanol and ethanol; ethers such as tetrahydrofuran; glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; methyl cellosolve acetate, ethyl cellosolve acetate and the like. Ethylene glycol alkyl ether acetates; diethylene glycols such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether; propylene glycol monoalkyl ethers such as propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol butyl ether; Propylene glycol Propylene glycol alkyl ether acetates such as methyl ether ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, propylene glycol butyl ether acetate; propylene glycol methyl ether propionate, propylene glycol ethyl ether propionate, propylene glycol propyl Propylene glycol alkyl ether propionates such as ether propionate and propylene glycol butyl ether propionate; aromatic hydrocarbons such as toluene and xylene; methyl ethyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone and the like Ketones; methyl acetate, ethyl acetate, propyl acetate, butyl acetate, - hydroxypropionic acid ethyl, 2-hydroxy-2-methylpropionic acid methyl,
Ethyl 2-hydroxy-2-methylpropionate, methyl hydroxyacetate, ethyl hydroxyacetate, butyl hydroxyacetate, methyl lactate, ethyl lactate, propyl lactate,
Butyl lactate, methyl 3-hydroxypropionate, 3-
Ethyl hydroxypropionate, Propyl 3-hydroxypropionate, Butyl 3-hydroxypropionate,
Propyl 2-hydroxy-3-methylbutanoate, methyl methoxyacetate, ethyl methoxyacetate, propyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, propyl ethoxyacetate, butylacetate, methyl propoxyacetate, ethyl propoxyacetate, Propoxy propyl acetate, Propoxy butyl acetate,
Methyl butoxyacetate, ethyl butoxyacetate, propyl butoxyacetate, butyl butoxyacetate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate, 2-
Propyl methoxypropionate, butyl 2-methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate, propyl 2-ethoxypropionate, butyl 2-ethoxypropionate, methyl 2-butoxypropionate, 2-butoxy Ethyl propionate, propyl 2-butoxypropionate, butyl 2-butoxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 3-ethoxypropione Methyl acid, ethyl 3-ethoxypropionate, propyl 3-ethoxypropionate, butyl 3-ethoxypropionate, methyl 3-propoxypropionate, ethyl 3-propoxypropionate, 3-propoxyp Acid propyl, 3-propoxy-propionic acid butyl, 3-butoxy-propionic acid methyl 3- butoxy-propionic acid ethyl, 3-butoxy-propionic acid propyl, 3-butoxy esters such as acid butyl.

Among these, glycol ethers, ethylene glycol alkyl ether acetates, esters and diethylene glycols are selected from the viewpoints of solubility of each component, reactivity with each component, and ease of forming a coating film. It is preferably used. These organic solvents can be used alone or in combination of two or more kinds.

A high boiling point solvent may be used in combination with the above organic solvent. Specific examples of such a high boiling point solvent include N-methylformamide, N, N-dimethylformamide, N-methylformanilide, N-methylacetamide, N, N-dimethylacetamide, N-
Methylpyrrolidone, dimethyl sulfoxide, benzyl ethyl ether, dihexyl ether, acetonyl acetone, isophorone, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate. , Γ-butyrolactone, ethylene carbonate, propylene carbonate, phenyl cellosolve acetate and the like. These high boiling point solvents can be used alone or in combination of two or more kinds together with the above organic solvents.

The ratio of the component (C) to be used is not particularly limited and may be appropriately selected according to the purpose of use, but it is usually used in such a ratio that the solid content concentration in the composition is 5 to 50% by weight. To be done.

<Other Components> In the composition for forming a protective film of the present invention, in addition to the components (A) to (C) described above, components are added in order to impart adhesion of the formed protective film to the substrate. As (D), a compound having an alkoxysilano group and an epoxy group can be used, and if necessary, for example, a curing accelerator, a surfactant, an epoxy resin, an ultraviolet absorber, etc. may be contained. .

[Component (D)] Specific examples of the compound having an alkoxysilano group and an epoxy group which can be used as the component (D) include γ-glycidoxypropyltrimethoxysilane and β- (3,4). -Epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyldiethoxysilane and the like can be mentioned, and these compounds can be used alone or in combination of two or more kinds.

The proportion of component (D) used is usually 0.1 to 200 parts by weight, preferably 5 to 150 parts by weight, per 100 parts by weight of component (A). When the ratio of the component (D) is less than 0.1 part by weight, the effect of imparting adhesion of the formed protective film to the substrate cannot be sufficiently obtained. On the other hand, when the proportion of the component (D) exceeds 200 parts by weight, the alkali resistance, solvent resistance, etc. of the protective film formed may be deteriorated.

[Curing Accelerator] The curing accelerator is the component (A).
The compound having a heterocyclic structure containing a secondary nitrogen atom or a tertiary nitrogen atom is generally used to accelerate the reaction between the compound and the component (B). Specific examples of such compounds include pyrrole, imidazole,
Examples thereof include pyrazole, pyridine, pyrazine, pyrimidine, indole, indazole, benzimidazole, isocyanuric acid, and derivatives thereof. Among these, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-heptadecylimidazole, 4-methyl-2-phenylimidazole, 1
-Benzyl-2-methylimidazole, 2-ethyl-4
-Methyl-1- (2'-cyanoethyl) imidazole,
2-ethyl-4-methyl-1- [2 '-(3 ", 5"-
Imidazole derivatives such as diaminotriazinyl) ethyl] imidazole and benzimidazole are preferred, most preferably 2-ethyl-4-methylimidazole, 4
-Methyl-2-phenylimidazole and 1-benzyl-2-methylimidazole are used. These compounds can be used alone or in combination of two or more as a curing accelerator. The curing accelerator is used in an amount of 0 to 30 parts by weight, particularly 0.
It is preferably used in a proportion of 1 to 10 parts by weight.

[Surfactant] As the surfactant, a fluorine-based surfactant and a silicone-based surfactant can be preferably used. As the fluorine-based surfactant, a compound having a fluoroalkyl or fluoroalkylene group at at least one of the terminal, main chain and side chain can be preferably used, and specific examples thereof include 1,
1,2,2-Tetrafluorooctyl (1,1,2,2-
Tetrafluoropropyl) ether, 1,1,2,2-tetrafluorooctylhexyl ether, octaethylene glycol di (1,1,2,2-tetrafluorobutyl)
Ether, hexaethylene glycol (1, 1, 2,
2,3,3-hexafluoropentyl) ether, octapropylene glycol di (1,1,2,2-tetrafluorobutyl) ether, hexapropylene glycol di (1,1,2,2,3,3-hexafluoro) Pentyl) ether, sodium perfluorododecyl sulfonate,
1,1,2,2,8,8,9,9,10,10-decafluorododecane, 1,1,2,2,3,3-hexafluorodecane and the like can be mentioned. Moreover, as these commercial items, BM-1000, BM-1100 (above, B
M Chemie), Megafac F142D, F172, F173, F183 (all manufactured by Dainippon Ink and Chemicals, Inc.) and the like.

Further, as the silicone type surfactant,
For example, Torre silicone DC3PA, SH7PA, DC11PA, SH21PA, SH28PA, S
H29PA, SH30PA (all manufactured by Toray Silicone Co., Ltd.), TSF-4440, TSF-4300, T
SF-4445, TSF-4446, TSF-446
0, TSF-4452 (above, Toshiba Silicone Co., Ltd.)
Commercially available products under the trade names such as (made by Japan) can be mentioned.

These surfactants can be used alone or in combination of two or more kinds. The proportion of the surfactant used varies depending on the type and proportion of each component constituting the composition, but in general, the component (A) 1
0-5 parts by weight, especially 0.001-2
A range of parts by weight is preferred.

[Epoxy Resin] As the epoxy resin,
A bisphenol A type epoxy resin, a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, a glycidyl ester type epoxy resin, a glycidyl amine type epoxy resin, a heterocyclic epoxy resin or the like can be used.

<Protective Film-Forming Composition> The protective film-forming composition of the present invention comprises a component (A) composed of the specific polymer.
And a component (B) comprising at least one compound selected from polyvalent carboxylic anhydride and polyvalent carboxylic acid
And a component (C) composed of an organic solvent, and a component (D) composed of a compound having an alkoxysilano group and an epoxy group, a curing accelerator, a surfactant, an epoxy resin, etc., which are further used as necessary. It is used as a solution-like composition containing the same. The solution viscosity of this solution composition at 30 ° C. is preferably 3 to 25 cPs, and particularly preferably 5 to 14 cPs. By using a composition having a solution viscosity at 30 ° C. of 3 to 25 cPs in the composition of the present invention, it is possible to form a coating film having a flatness of 20% or less as measured by the method described below. Furthermore, in the composition of the present invention, by using a solution having a solution viscosity at 30 ° C. of 5 to 14 cPs, a coating film having a flatness of 15% or less can be formed.

<Formation of protective film> By using the composition for forming a protective film of the present invention, a protective film can be formed, for example, as follows. That is, the protective film-forming composition is applied to the surface of the substrate on which the protective film is to be formed, and then the coating film is heat-treated and cured to form the protective film.

In the above, the method of applying the composition for forming a protective film is not particularly limited, and various methods such as a spray method, a roll coating method and a spin coating method (spin coating method) can be adopted. . The conditions for the heat treatment vary depending on the type and proportion of each component in the composition, but are usually at 150 to 250 ° C. for about 0.2 to 1.5 hours.

The protective film formed by the protective film-forming composition of the present invention has high surface flatness and various physical properties, as will be apparent from the following examples. It is extremely suitable as a protective film for optical devices such as color filters.

[0042]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the following examples, the weight average molecular weight (Mw) of the specific polymer and the viscosity of the solution of the protective film forming composition were measured by the following methods. Weight average molecular weight: Tosoh GPC column (TSK g
el G2000H 2 pieces, G3000H 1 piece, G4
Flow rate 1.0 ml /
Minutes, elution solvent tetrahydrofuran, and a column temperature of 40 ° C. were used for analysis, and the measurement was carried out by gel permeation chromatography using monodisperse polystyrene as a standard. Viscosity: The viscosity at 30 ° C was measured using an E-type viscometer (manufactured by Tokyo Keiki Co., Ltd.).

<Synthesis of Specific Polymer> [Synthesis Example 1] 80 parts by weight of glycidyl methacrylate as a specific monomer and 20 parts by weight of methyl methacrylate as another monomer are used, and these monomers are mixed with ethyl cellosolve. 2 parts by weight of azobisisobutyronitrile (hereinafter referred to as "AIBN") as a polymerization initiator was added to 300 parts by weight of acetate and mixed, and in this mixed monomer solution.
After adding 5 parts by weight of dodecyl mercaptan as a molecular weight modifier, the mixed monomer was polymerized at 95 ° C. for 3 hours to obtain a polymer solution containing the specific polymer (A1). Then, the obtained polymer solution was dropped into a large amount of methanol to give a specific polymer (A
1) was solidified. The coagulated product of the specific polymer (A1) was washed with water, dissolved in tetrahydrofuran, and the solution was added dropwise to a large amount of methanol to coagulate the specific polymer (A1) again. The operation of dissolving and coagulating the specific polymer (A1) was performed three times in total, and then the obtained coagulated product was vacuum dried at 60 ° C. for 48 hours to purify the specific polymer (A1). It was A polymer solution (S1) was prepared by dissolving the specific polymer (A1) in ethyl cellosolve acetate as the component (C) so that the concentration was 25% by weight. The weight average molecular weight of the obtained specific polymer (A1) was 2,100.

[Synthesis Example 2] The same procedure as in Synthesis Example 1 was repeated except that 60 parts by weight of glycidyl methacrylate was used as the specific monomer and 4 parts by weight of dicyclopentanyl methacrylate was used as the other monomer. A polymer (A2) was obtained and purified to prepare a polymer solution (S2). The weight average molecular weight of the obtained specific polymer (A2) was 3,200.

[Synthesis Example 3] A specific polymer (A3) was obtained in the same manner as in Synthesis Example 1 except that 3 parts by weight of dodecyl mercaptan was used as a molecular weight regulator, and was purified.
A polymer solution (S3) was prepared. The weight average molecular weight of the obtained specific polymer (A3) was 7,900.

[Synthesis Example 4] The same procedure as in Synthesis Example 1 except that 70 parts by weight of glycidyl methacrylate was used as the specific monomer, and 20 parts by weight of methyl methacrylate and 10 parts by weight of styrene were used as the other monomers. A specific polymer (A4) was obtained and purified to obtain a polymer solution (S4).
Was prepared. The weight average molecular weight of the obtained specific polymer (A4) was 4,100.

[Synthesis Example 5] A specific polymer (A5) was obtained and purified in the same manner as in Synthesis Example 1 except that 5 parts by weight of AIBN was used as a polymerization initiator without using a molecular weight regulator. Then, a polymer solution (S5) was prepared. The weight average molecular weight of the obtained specific polymer (A5) was 4900.
Met.

Synthesis Example 6 A specific polymer (A6) was prepared in the same manner as in Synthesis Example 1 except that 70 parts by weight of glycidyl methacrylate was used as the specific monomer and 30 parts by weight of styrene was used as the other monomer. ) Was obtained, and this was purified to prepare a polymer solution (S6). The weight average molecular weight of the obtained specific polymer (A6) was 3,000.

[Synthesis Example 7] A specific polymer (A7) was obtained in the same manner as in Synthesis Example 1 except that 5 parts by weight of α-methylstyrene dimer was used as a molecular weight modifier. A combined solution (S7) was prepared. The weight average molecular weight of the obtained specific polymer (A7) was 4000.

[Comparative Synthesis Example 1] A molecular weight modifier was not used, 1 part by weight of AIBN was used as a polymerization initiator, and the temperature was 80 ° C.
Comparative polymer (A8) was obtained in the same manner as in Synthesis Example 1, except that the mixed monomer was polymerized under the conditions of 3 hours, and was purified to prepare a comparative polymer solution (S8). did. The weight average molecular weight of the obtained comparative polymer (A8) was 32,000.

Comparative Synthesis Example 2 A comparative polymer (A9) was obtained in the same manner as in Synthesis Example 1 except that the molecular weight modifier was not used, and a comparative polymer solution (S9) was prepared. The weight average molecular weight of the obtained comparative polymer (A9) was 16,000.

Example 1 100 parts by weight of the polymer solution (S1) was added to the component (C), ethyl cellosolve acetate 2.
After diluting with 5 parts by weight, this solution (specific polymer (A
1) 25 parts by weight and ethyl cellosolve acetate 10
0 parts by weight), 7.5 parts by weight of trimellitic anhydride as the component (B), 5 parts by weight of γ-glycidoxypropyltrimethoxysilane as the component (D), and 1-benzyl-2 as the curing accelerator. -Methylimidazole 0.075 parts by weight, and a fluorochemical surfactant "BM" as a surfactant.
-1000 (manufactured by BM Chemie) was added in an amount of 0.025 part by weight and sufficiently stirred to obtain a protective film-forming composition of the present invention. The solution viscosity of this protective film forming composition was 7.6 cPs.

[Formation of Protective Film] Formation Example (1) Using a spin coater, the above composition for forming a protective film was applied onto a glass substrate so that the film thickness was 2 μm, and then in a clean oven. A heat treatment was performed at 200 ° C. for 1 hour to form a protective film on the glass substrate. Forming Example (2) Stripe-shaped three color filters of red, blue and green were dyed by a dyeing method on a glass substrate "Corning 7059 (manufactured by Douglas Dow Corning)" using gelatin and a potassium dichromate solution. Formed (stripe width 15
0 μm). When the unevenness of the surface of the substrate on which the color filter was formed was examined using "α-step" (manufactured by Tencor Co.), it was 1.0 µm. On the color filter formed on this substrate, a protective film was formed by applying the composition for forming a protective film and performing heat treatment in the same manner as in the above-mentioned formation example (1).

[Evaluation of Protective Film] Adhesion: According to the 8.5.2 cross-cut tape method in the adhesion test of JIS K-5400 (1900) 8.5.
On the protective film formed by the above-mentioned formation example (1) and formation example (2), 100 cross-cuts were formed with a cutter knife, an adhesion test was conducted, and the number of peeled cross-cuts was measured. The adhesiveness of the protective film was evaluated by. ○: 5 or less △: 6 to 49 ×: 50 or more

Surface hardness: JIS K-5400 (199
0) Of the pencil scratch test of 8.4, according to the 8.4.1 test method, a pencil scratch test is performed on the protective film formed by the above-mentioned formation example (1) to evaluate the surface hardness of the protective film. went.

Acid resistance: The glass substrate on which the protective film was formed according to the above-mentioned formation example (1) was immersed in a 20% by weight hydrogen chloride aqueous solution at 40 ° C. for 10 minutes, and then the appearance of the protective film was examined. The acid resistance of the protective film was evaluated.

Alkali resistance: After immersing the glass substrate on which the protective film is formed according to the above-mentioned formation example (1) in a 10% by weight aqueous sodium hydroxide solution at 40 ° C. for 60 minutes, the appearance of the protective film is examined. Thus, the alkali resistance of the protective film was evaluated.

Heat resistance; wavelength of 400 to 700 n with respect to the glass substrate on which the protective film is formed according to the above formation example (1)
After measuring the transmission spectrum at m, and then heating this substrate in a clean oven at 250 ° C. for 60 minutes, the transmission spectrum at a wavelength of 400 to 700 nm is measured, and the change in the transmission spectrum before and after heating is examined. The heat resistance of the protective film was evaluated according to the standard. ◯: Change in transmission spectrum is less than 1% x: Change in transmission spectrum is 1% or more

Surface flatness: The unevenness of the surface of the protective film formed by the above-mentioned formation example (2) was examined by using "α-step", and the unevenness of the surface of the substrate by the color filter was calculated by the following formula. The flatness degree was calculated. Table 1 shows the above results.

[0060]

(Equation 1)

Examples 2 to 7 Instead of the polymer solution (S1), the polymer solution (S2) to the polymer solution (S
The composition for forming a protective film of the present invention was prepared in the same manner as in Example 1 except that 7) was used, and a protective film was formed using these, and the evaluation was performed. Table 1 shows the results.

Example 8 A protective film-forming composition of the present invention was prepared in the same manner as in Example 1 except that 10 parts by weight of bisphenol A type epoxy resin was added, and a protective film was formed using the composition. It was formed and evaluated. Table 1 shows the results.

Comparative Example 1 A comparative composition was prepared in the same manner as in Example 1 except that the comparative polymer solution (S8) was used in place of the polymer solution (S1). A protective film was formed using this, and the evaluation was performed. Table 1 shows the results
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Comparative Example 2 A comparative composition was prepared in the same manner as in Example 1 except that the comparative polymer solution (S9) was used in place of the polymer solution (S1). A protective film was formed using this, and the evaluation was performed. Table 1 shows the results
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[0065]

[Table 1]

As is clear from Table 1, the protective films formed from the protective film-forming compositions according to Examples 1 to 8 have high surface flatness and excellent physical properties. Met. On the other hand, in the compositions according to Comparative Example 1 and Comparative Example 2, since the polymer having a weight average molecular weight of more than 10,000 was used, a protective film having high surface flatness could not be formed. .

[0067]

According to the protective film forming composition of the present invention,
Even if the substrate has a non-flat surface, a protective film having high surface flatness can be formed on the substrate. Also,
The protective film formed from the composition of the present invention has high surface hardness and is excellent in various resistances such as heat resistance, acid resistance and alkali resistance.

Claims (1)

[Claims] 1. A polymer or copolymer comprising (A) at least 20% by weight of a structural unit represented by the following general formula (1) and having a polystyrene-reduced weight average molecular weight of 2000 to 10,000. A composition for forming a protective film, comprising: (B) at least one compound selected from a polycarboxylic acid anhydride and a polycarboxylic acid; and (C) an organic solvent. Embedded image [In the formula, R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and m represents an integer of 1 to 8. ]