JP2002035684A - Method for forming protective film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a protective film excellent in transparency. SOLUTION: A composition containg at least a polymer and a solvent is applied on a substrate to form a coating film, the coating film is heated in an inert gas atmosphere and cured, and the protective film is formed on the substrate by this method. Meanwhile, an article having the protective film formed by the method is furnished.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a protective film for an optical device. More specifically, the present invention relates to a method for forming a highly transparent protective film on a display portion of an optical device, particularly a liquid crystal display element.

2. Description of the Related Art In manufacturing optical devices, particularly liquid crystal display elements,
A color filter is provided on a transparent substrate such as glass, and indium tin oxide (hereinafter referred to as ITO) is provided on the color filter.
After depositing an inorganic thin film made of such as, and forming a transparent electrode by patterning by photolithography method,
Further, a method of disposing a liquid crystal thereon has become mainstream. In such a case, the color filter itself includes:
It does not have the heat and chemical resistance to withstand the process of depositing ITO and forming a transparent electrode by photolithography, so it is necessary to form a protective film on the color filter before depositing ITO. is there.

The properties required for this protective film include heat resistance, chemical resistance, adhesion, transparency, and others. In particular, since a protective film used for an optical device is required to have transparency, preferably a transparency of 95% or more in transmittance, various compositions for forming a protective film are required to provide more excellent transparency. Are being considered. However, no matter which protective film-forming composition is used, when a protective film is formed by a conventional protective film forming method, the transparency of the protective film at the time of heat curing in the formation process, specifically, There is a problem that transmittance decreases.

[0004] In the composition for forming a photosensitive protective film, even if exposure and development are performed to form a protective film,
In many cases, sufficient transparency cannot be obtained. In such a case, in order to further improve the transparency, a process called bleaching in which exposure is performed again after exposure is required. Performing exposure again in this manner is not preferable from the viewpoint of manufacturing efficiency.

[0005] In order to solve such problems, there has been a demand for a method of forming a protective film for efficiently producing a protective film having high transparency.

[0006]

SUMMARY OF THE INVENTION In order to solve such problems, the present inventors have conducted a heat-curing step under an inert gas atmosphere while using a conventionally known composition for forming a protective film. It has been found that a protective film having excellent transparency can be formed without sacrificing any properties.

That is, the present invention provides a protective film forming composition comprising a polymer and a solvent, which is applied to a substrate to form a film, and the film is cured by heating to form a film on the substrate. A method for forming a protective film,
The heating is performed in an inert gas atmosphere.

According to the method of the present invention, a protective film having excellent transparency can be efficiently formed using a conventionally known composition for forming a protective film. In particular, the composition for forming a photosensitive protective film does not require a re-exposure step which has been conventionally required in most cases.

[0009]

DETAILED DESCRIPTION OF THE INVENTION <Protective film forming composition> Any known protective film forming composition may be used as the protective film forming composition used in the protective film forming method of the present invention. Can be. Such a composition for forming a protective film,
It comprises a polymer, a solvent and, if necessary, other components.

[0010] The composition for forming a protective film may be a thermosetting composition or a photosensitive composition. When the composition is a photosensitive composition, the composition may be a negative photosensitive composition or a positive photosensitive composition. The components of the composition for forming a protective film can be arbitrarily selected according to the type. The components of the composition are not particularly limited as long as the effects of the present invention are not impaired. The general components of the composition for forming a protective film will be described below for each type of composition.

[0011] 1. Thermosetting Composition When the composition for forming a protective film used in the method of the present invention is a thermosetting composition, the composition generally contains a crosslinking agent in addition to the polymer and the solvent. (A) Polymer In the present invention, when the composition for forming a protective film is a thermosetting composition, the polymers are heated to form a polymer,
Or a cross-linking reaction occurs between the polymer and the cross-linking agent,
It cures to form a coating. Such a polymer can be arbitrarily selected depending on the purpose, but one of preferred ones is a polymer having a carboxyl group (hereinafter, referred to as a carboxyl group-containing polymer).

Preferred specific examples of such a polymer include a copolymer of acrylic acid, methacrylic acid, or an ester thereof, and a vinyl aromatic compound. Examples of acrylic acid, methacrylic acid, or esters thereof include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, ethylhexyl methacrylate, phenyl acrylate, and the like. . Examples of the vinyl aromatic compound include styrene, α-methylstyrene, p-methylstyrene, and others.

The copolymer form of the copolymer is not particularly limited, and may be any of a random copolymer and a block copolymer by addition polymerization. Further, the copolymerization method is not particularly limited, and may be performed by a solution polymerization method, an emulsion polymerization method, or the like.

The molecular weight of the carboxyl group-containing polymer is
Although not particularly limited, styrene-equivalent weight average molecular weight is 2,
It is preferably from 000 to 200,000. The weight average molecular weight of this polymer is preferably about 7,000 to 100,000.

Another preferred polymer is a polymer having a hydroxyl group. Various polymers are known as such a polymer, and any polymer can be used, and a more preferable one is a phenol-novolak resin. It is formed by reacting phenols, such as phenol, m-cresol, 3,5-xylenol, p-alkylphenol, resorcinol, and others, with aldehydes, such as formaldehyde, acetaldehyde, and others. is there. The specific production method can be selected from any of the general methods used for the production of phenol novolak resins.However, from the viewpoint of the reaction rate, it is common to use an acid or alkali as a catalyst. .

(B) Solvent In the present invention, an organic solvent is used as a solvent for dissolving the solid component such as the polymer described above. According to a preferred embodiment of the present invention, the organic solvent is propylene glycol, ethylene glycol, lactic acid, butyric acid, acetic acid,
It is preferably selected from the group consisting of formic acid, γ-butyrolactone solvents and mixtures thereof.
By using these organic solvents, the obtained coating composition is stable for about 6 months after preparation, and furthermore, a uniform coating film without coating unevenness is obtained. As a result,
A protective film having excellent adhesion, flatness, and transparency, and having excellent durability, abrasion resistance, stain resistance, and chemical resistance can be obtained.

Specific examples of the organic solvent include glycol ethers and acetate solvents such as propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol-t-butyl ether, dipropylene glycol methyl ether, and dipropylene glycol. Propyl ether, tripropylene glycol methyl ether, propylene glycol methyl ether acetate, dipropylene glycol methyl ether acetate, ethylene glycol ethyl ether, ethylene glycol methyl ether, ethylene glycol butyl ether, ethylene glycol isopropyl ether, ethylene glycol-n-butyl ether, cellosolve acetate , Methyl celloso Bed acetate, ethyl cellosolve Sete - DOO, diethylene glycol methyl ether,
Diethylene glycol ethyl ether, diethylene glycol butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monoacetate, diethylene glycol monoethyl ether acetate, propylene glycol phenyl ether, propylene glycol ethyl ether acetate, triethylene glycol butyl ether, 3-methyl-3-methoxy Butyl acetate, 3
-Methyl-3-methoxybutanol. Examples of the lactic acid-based solvent include ethyl lactate, methyl lactate, butyl lactate, and pentyl lactate. Examples of the acetic acid-based solvent include butyl acetate, amyl formate, isoamyl acetate, isobutyl acetate, methoxybutyl acetate, and butyl propionate, and examples of the butyric acid-based solvent include isobutyl butyrate, butyl butyrate, and ethyl pyruvate.

Further, according to a preferred embodiment of the present invention,
It is preferable to use propylene glycol methyl ether acetate or a mixed organic solvent containing at least this as the organic solvent. When using a mixed organic solvent containing propylene glycol methyl ether acetate, preferred organic solvents used with propylene glycol methyl ether acetate include propylene glycol, ethylene glycol, lactic acid, butyric acid, acetic acid, formic acid, γ -Butyrolactone solvents and mixtures thereof.

(C) Crosslinking Agent In the present invention, when the composition for forming a protective film is a thermosetting composition, the composition generally contains a crosslinking agent component. Although such a crosslinking agent component is not particularly limited,
It is preferably an epoxy compound. Novolak epoxy resin, bisphenol A
Type epoxy resin, halogenated bisphenol A type epoxy resin, alicyclic epoxy resin, and others.

Specific examples of preferred crosslinking agents include bisphenolacetone diglycidyl ether, phenol novolak epoxy resin, cresol novolak epoxy resin, triglycidyl isocyanurate, tetraglycidyldiaminodiphenylene, tetraglycidyl-m-xylenediamine, and tetraglycidyl- 1,3-bis (aminoethyl) cyclohexane, tetraphenylglycidyl ether ethane, triphenyl glycidyl ether ethane, bisphenol hexafluoroacetodiglycidyl ether, 1,3-bis (1- (2,3-epoxypropoxy) -1- Trifluoromethyl-2,2,2-trifluoromethyl) benzene, 4,4-bis (2,3-
Epoxypropoxy) octafluorobiphenyl, triglycidyl-p-aminophenol, tetraglycidylmethaxylenediamine, 2- (4- (2,3-epoxypropoxy) phenyl) -2- (4- (1,1-bis (4 -(2,3-epoxypropoxy) phenyl) ethyl) phenyl) propane, 1,3-bis (4- (1-
(4- (2,3-epoxypropoxy) phenyl) -1
-(4- (1- (4- (2,3-epoxypropoxyphenyl) -1-methylethyl) phenyl) ethyl) phenoxy) -2-propanol and the like.

The crosslinking agent component may be introduced into the carboxyl group-containing polymer in the form of a substituent instead of the compound. At this time, the crosslinking agent component is preferably introduced as an epoxy group or as a residue of the above-mentioned crosslinking agent.

(D) Other Ingredients In the present invention, the composition for forming a protective film may contain various additives as required in addition to the above-mentioned ingredients. Here, as other additives, in addition to the crosslinking agent, a sensitizer, a leveling agent, an adhesion enhancer, a surfactant,
Examples include antioxidants, thickeners, ultraviolet absorbers, reaction accelerators, and others.

The composition for forming a protective film used in the method for forming a protective film according to the present invention includes a leveling agent such that when the composition for forming a protective film is applied on a substrate, the surface of the film becomes uniform. Can be used. Leveling agents used include silane-based leveling agents, fluorine-based leveling agents, and others.

Further, the composition for forming a protective film used in the method for forming a protective film of the present invention may be used in such a manner that the composition for forming a protective film applied on a substrate adheres to the substrate with sufficient strength.
An adhesion enhancer can be included.

As the adhesion enhancer, any one can be used. As such an adhesion enhancer, for example,
Examples include an alkoxysilane compound, an alkoxytitanium compound, an alkoxyzirconium compound, an alkoxyaluminum compound, and others. In particular, an amino group-containing silane compound represented by the following general formula (I) is preferable. H ₂ N—R ¹¹ —Si— (OR ¹² ) ₃ (I) (wherein, R ¹¹ is an unsubstituted alkylene group, and R ¹² is each independently an unsubstituted alkyl group.)

Among such amino group-containing silane compounds, a good protective film can be formed particularly when 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane are used.

The composition for forming a protective film used in the method for forming a protective film of the present invention may contain a surfactant or a surfactant in order to improve the coatability of the composition for forming a protective film on a substrate. Thickeners may be included. Any of conventionally known surfactants and thickeners can be used.

Further, in the method of the present invention, when the composition is a thermosetting composition, it may contain a reaction accelerator for accelerating a polymerization reaction occurring during heating or irradiation with light. Examples of such a reaction accelerator include an imidazole compound.

When an imidazole compound is used in the composition for forming a protective film, the formed protective film has improved resistance when subjected to sputtering conditions. As such an imidazole compound, a compound represented by the following general formula (II) is preferably used.

Embedded image (Where R ²¹ and R ²² are each independently hydrogen or a substituted or unsubstituted alkyl group, R ²³ is a hydrogen, a substituted or unsubstituted alkyl group, or an aryl group R
²⁴ is hydrogen, a substituted or unsubstituted alkyl group. )

Of these, 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-phenyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecyl Imidazole, 1,2-dimethylimidazole, 2-phenylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2 -Undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 2,4-diamino-6- (2′-methylimidazolyl- (1 ′))-ethyl-s-triazine, 2,4-
Diamino-6- (2'-undecylimidazolyl) -ethyl-s-triazine, 2,4-diamino-6- (2 '
-Ethyl-4-methylimidazolyl- (1 '))-ethyl-s-triazine, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-
It is preferable to use 5-hydroxymethylimidazole and 1-cyanoethyl-2-phenyl-4,5-di (2-cyanoethoxy) methylimidazole.

2. Negative photosensitive composition When the composition for forming a protective film used in the method of the present invention is a negative photosensitive composition, in addition to the polymer and the solvent, the composition is generally a photopolymerization initiator and A cross-linking agent is optionally included.

(A) Polymer In the present invention, when the composition for forming a protective film is a negative-type photosensitive composition, the polymer is initiated between polymers or between a polymer and a photopolymerization by the contribution of a photopolymerization initiator described later. A cross-linking reaction occurs between the agent and the agent, and the agent cures to form a film. Such polymers are generally
It has a chain portion and a reaction site capable of binding to a reaction site of a photopolymerization initiator or another polymer.

[0033] Such polymers are widely known in the art and can be arbitrarily selected according to the purpose.
Among these polymers, one preferred in the method of the present invention is a polymer containing a segment represented by the following general formula (III) and a compound selected from the group consisting of (3,4-epoxycyclohexyl) methacrylate and a derivative thereof. And the reaction product of

Embedded image In the formula, R ³¹ may be the same or different, and represents a substituent selected from the group consisting of a hydrogen atom and a methyl group, and R ³² represents an alkyl group having a linear or branched chain structure having 1 to 5 carbon atoms. Express. Also, m and n represent the degree of polymerization, and m / n is 0.5 to 2.4 (molar ratio).

In particular, in the above general formula (III), R
³¹ is preferably at least one is a methyl group,
R ³² is preferably an alkyl group having 1 to 4 carbon atoms, and particularly preferably an n-butyl group. Furthermore,
More preferably, the general formula (III) is a polymer containing a segment represented by the following general formula (IV).

Embedded image (In the formula, m and n are defined as above.) In addition, m / n is in a range of 0.5 to 2.4 in a molar ratio,
It is preferably in the range of 0.6 to 1.7.

In addition, a phenol novolak resin can be used instead of the polymer of the general formula (III). Examples of such a phenol novolak resin are the same as those described above in the section of the thermoplastic composition.

The compounds selected from the group consisting of (3,4-epoxycyclohexyl) methacrylate and derivatives thereof include those having various substituents, and in particular, (3,4-epoxycyclohexyl) methyl methacrylate is preferred. preferable

The molecular weight (Mw) of the reaction product of the polymer and (3,4-epoxycyclohexyl) methacrylate is preferably in the range of 10,000 to 80,000, more preferably in the range of 15,000 to 40,000. preferable. The acid value of the reaction product is preferably from 20 to 100 mgKOH / g, and more preferably from 45 to 70 mgKOH / g.

(B) Even when the composition for forming a solvent protective film is a negative photosensitive composition, an organic solvent is used as a solvent for dissolving the solid component such as the polymer described above. Can be selected from the same ones as in the case of the above-mentioned thermosetting composition.

(C) Photopolymerization initiator As the photopolymerization initiator, any conventionally known photopolymerization initiator can be used. For example, an azide compound, a halomethyloxazole-based compound, a halomethyl-s-triazine compound, Onium salts, benzoin ethers, xanthones, acetophenone derivatives, and others.

As the azide compound, (i) azidostilbenes and derivatives thereof, for example, 4,4'-diazidostilbene and 4,4'-diazidostilbene-2,2'-
Disulfonic acid-N, N-diethyleneoxyethylamide, 4,4'-diazidostilbene-2,2'-disulfonic acid-N-propylhydroxyamide, 4,4'-diazidostilbene-2,2'-disulfone Acid, 4,4 '
-Diazidostilbene-2,2'-disulfonic acid-N,
N-diethylamide, 4,4'-diazidostilbene-
Sodium 2,2'-disulfonate, and others, (i
i) Azidobenzalcyclohexanone and its derivatives, for example, 2,6-di- (p-azidobenzal) -cyclohexanone, 2,6-di- (p-azidobenzal)-
4-methylcyclohexanone, 2,6-di- (p-azidobenzal) -4-tert-amylcyclohexanone, 2,6-di- (p-azidocinnamylidene) -4-
tert-aminocyclohexanone and others, (i
ii) azidocinnamylidenecyclohexanone and derivatives thereof, (iv) azidobenzal ketones, p-azidobenzalacetophenone, p-azidobenzalacetone,
4,4′-diazidochalcone, 2,6-bis (4′-azidobenzal) acetone, 2,6-bis (4′-azidobenzal) acetone-2′-sulfonic acid-N, N-diethyleneoxyethylamide, 2,6-bis (4'-azidobenzal) -acetone-2,2'-disulfonic acid-
N, N-diethyleneoxyethylamide, and others. Further, those in which an azide group is introduced into a polymer chain can also be used.

Examples of halomethyl oxazole compounds include 2-trichloromethyl-5-styryl-1,
3,4-oxadiazole, 2-trichloromethyl-5
-(P-cyanostyryl) -1,3,4-oxadiazole, 2-trichloromethyl-5- (p-methoxystyryl) -1,3,4-oxadiazole, and others.

As the halomethyl-s-triazine compound, particularly, a trihalomethyl-s-triazine compound such as 2,4-bis (trichloromethyl) -6-p
-Methoxystyryl-s-triazine, 2,4-bis (trichloromethyl) -6- (1-p-diethylaminophenyl-1,3-butadienyl) -s-triazine,
2,4-bis (trichloromethyl) -6- (p-phenylstyryl) -s-triazine, 2,4-bis (trichloromethyl) -6-styryl-s-triazine, 2,4
-Bis (trichloromethyl) -6-phenyl-s-triazine, 2 [2 '(5 "-methylfuryl) ethylidene]
-4,6-bis (trichloromethyl) -s-triazine, 2 (2'-furylethylidene) -4,6- (trichloromethyl) -s-triazine, 5,7-bis (tribromomethyl) -s- Triazolo [1,5-a] pyrimidine and others.

The benzoin ethers include, for example, benzoin methyl ether, benzoin isobutyl ether, and others. Benzophenones include, for example, acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, Michler's ketone, o-benzoylmethylbenzoate, and others. As xanthones, for example, xanthone, thioxanthone,
2-chlorothioxanthone, 2-alkylthioxanthone, 2,4-dialkylthioxanthone, and others.

Examples of the acetophenone derivative include acetophenone, trichloroacetophenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, and others.

Examples of the onium salt include various sulfonium salts, iodonium salts and diazonium salts. Specific examples include triphenylsulfonium trifluoromethanesulfonate, benzyl-4-hydroxyphenylmethylsulfonium, hexafluorophosphate, α
-Naphthylmethyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate (or hexafluoroantimonate), diphenyl-t-butylphenylsulfonium trifluoromethanesulfonate, diphenylmethoxyphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluoroantimonate, diphenyl -T-butylphenyliodonium trifluoromethanesulfonate (or hexafluoroantimonate or tetrafluoroborate), methoxyphenyliodonium trifluoromethanesulfonate, diphenyliodonium trifluoromethanesulfonate, aminophenylbenzenediazonium tetrafluoroborate, pyrylene azonium tetrafluoroborate And the like.

In the method of the present invention, the photopolymerization initiator can be arbitrarily selected from these. These may be used alone or in combination as necessary. These photopolymerization initiators may be added to the above-mentioned polymer in the form of a substituent, in addition to being added as a compound to the composition for forming a protective film. Among these, it is preferable to use a halomethyl-s-triazine compound, particularly a trihalomethyl-s-triazine compound.

(D) Crosslinking Agent In the method of the present invention, when the composition for forming a protective film is a negative photosensitive composition, the composition may further comprise a crosslinking agent, if necessary. As such a crosslinking agent,
Compounds having at least two same or different residues, such as alkoxy and acyloxy, which can be selected from the same ones used for the thermosetting composition, and which react with the polymer to form a crosslinked matrix. (Eg, bis-, tris- or tetra- (hydroxymethyl) -substituted aromatic or heteroaromatic compounds, bis-, tris- or tetra- (acetoxymethyl) -substituted aromatic compounds, or heteroaromatic compounds ), Melamine compounds (eg, melamine having an N-hydroxymethyl group, melamine having an N-alkoxymethyl group, or melamine having an N-acyloxymethyl group), acetal resins (eg, polyvinyl butyral), peroxide compounds (eg, benzoyl peroxide) , Parachlorobenzoyl Peroxide, acetyl peroxide, lauroyl peroxide), blocked isocyanates (e.g., isophorone diisocyanate, hexamethylene diisocyanate, cyclohexylene diisocyanate) and various other blocking agents such as ethanol, butanol, dimethyl malonate, imidazole, e-caprolactam, methyl cellosolve. , Ethylene glycol and others)
Can be selected. These may be used alone or in combination of two or more.

(E) Other Components In the method of the present invention, when the composition is a negative photosensitive composition, other components may be contained in addition to the above components. As such components, those mentioned in the section of other components used in the thermosetting composition can be used.

[0049] 3. Positive photosensitive composition When the composition for forming a protective film used in the method of the present invention is a positive photosensitive composition, in addition to the polymer and the solvent, the composition is generally a photosensitive component, and A cross-linking agent.

(A) Polymer In the present invention, when the composition for forming a protective film is a positive photosensitive composition, the polymer can be selected from the same ones as in the case of the above-mentioned thermosetting composition.

(B) Solvent In the present invention, when the composition for forming a protective film is a positive photosensitive composition, the solvent can be selected from the same ones as in the case of the above-mentioned thermosetting composition.

(C) Photosensitive Component When the composition for forming a protective film used in the present invention is a positive photosensitive composition, the composition contains a photosensitive component. Here, the photosensitive component means a component that absorbs light and initiates a polymerization reaction of the composition component. The composition for forming a protective film containing such a photosensitive component acts as a photosensitive composition.

The photosensitive component can be arbitrarily selected from those generally used in a positive photosensitive composition, but it is preferable to use a component containing a quinonediazide group.

As the photosensitive component, any of the conventionally known ones can be used. Preferred examples thereof include naphthoquinonediazidesulfonic acid chloride and benzoquinonediazidesulfonic acid chloride;
Examples include those produced by reacting acid chloride with a low molecular weight compound or a high molecular weight compound having a functional group capable of undergoing a condensation reaction.

Here, the functional group condensable with the acid chloride includes a hydroxyl group, an amino group and the like, and a hydroxyl group is particularly preferable. Examples of the low molecular compound containing a hydroxyl group include hydroquinone, resorcin, 2,4-dihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone, and 2,4,4′-triol. Hydroxybenzophenone,
2,3,4,4′-tetrahydroxybenzophenone,
2,2 ′, 4,4′-tetrahydroxybenzophenone, 2,2 ′, 3,4,6′-pentahydroxybenzophenone, and other polyhydroxybenzophenones, bis (2,4-dihydroxyphenyl) methane,
Bis (2,3,4-trihydroxyphenyl) methane,
Bis ((poly) hydroxyphenyl) alkanes such as bis (2,4-dihydroxyphenyl) propane-1,
4,4 ', 3 ", 4" -tetrahydroxy-3,5
3 ′, 5′-tetramethyltriphenylmethane, 4,
4 ', 2 ", 3", 4 "-pentahydroxy-3,5
3 ', 5'-tetramethyltriphenylmethane, 2,
3,4,2 ', 3', 4 ', 3 ", 4"-octahydroxy-5,5'-diacetyltriphenylmethane, and other polyhydroxytriphenylmethanes, and others. Examples of the high molecular compound include novolak resin, polyhydroxystyrene, and others.

In particular, it is preferable to use a photosensitive component having a methylene crosslinked body composed of a 1,2-naphthoquinonediazide skeleton and two or more phenolmethyl-substituted derivatives in the structure. By using such a photosensitive component, a protective film having higher transparency can be obtained. Here, the phenolmethyl-substituted derivative is one in which any hydrogen bonded to the carbon of the phenol skeleton is substituted with a methyl group. In the present invention, a derivative not substituted with a methyl group (that is, phenol itself) is also used. Shall be included. Therefore, a methylene crosslinked body composed of two or more phenolmethyl-substituted derivatives is one in which two or more phenol skeletons are connected by a methylene group and any hydrogen on the phenol skeleton is substituted by a methyl group. You can also.

In the present invention, the photosensitive component may have a plurality of 1,2-naphthoquinonediazide skeletons. It is sufficient that at least one 1,2-naphthoquinonediazide skeleton is contained in the structure of the photosensitizer. Although not particularly limited, 1 to 5 is preferable, and 2 to 4 is particularly preferable.

Among such photosensitive components, the photosensitive component used in the positive photosensitive composition used in the method of the present invention is at least one selected from the group consisting of the following formulas (Va) to (Vc). It is particularly preferred that

Embedded image Among the photosensitive components represented by these formulas, those in which three of the four Ds are esterified with 1,2-naphthoquinonediazidesulfonic acid are most preferred.

In the present invention, the photosensitive component has two or more phenol-methyl-substituted derivatives in its structure.
It is preferable that the number is four, especially four.

In the method of the present invention, the photosensitive component can be arbitrarily selected from these. These may be used alone or in combination as necessary. These photosensitive components may be added as a compound to the composition for forming a protective film, or may be introduced into the polymer in the form of a substituent.

(D) Crosslinking Agent In the method of the present invention, when the composition for forming a protective film is a positive photosensitive composition, a crosslinking agent may be included as necessary. Such a cross-linking agent can be selected from the same ones as in the case of the negative-type photosensitive composition described above, and is particularly preferably a melamine compound.

(E) Other Components In the method of the present invention, when the composition for forming a protective film is a positive photosensitive composition, it may contain various additives as necessary in addition to the above components. it can. As such additives, those described in the section of other components of the thermosetting composition can be used.

When the composition for forming a protective film is a positive photosensitive composition, a sensitizer may be added to improve the sensitivity to light irradiation. Examples of the sensitizer include 2-nitrofluorene, 2,4,7-trinitrofluorene, benzanthrone, picramide, 1,2-benzanthraquinone, 11-chloro-6-hydroxybenzanthrone, phenanthraquinone, -(4-butoxyphenyl) -2,6-diphenylthiopyrylium perchlorate and the like.

[0064] 4. Preparation of the composition

In the method of the present invention, the amount of the polymer to be added to the composition for forming a protective film may be appropriately determined as long as a good protective film can be realized. It is preferably 5 to 40% by weight, more preferably 10 to 30% by weight.

The amount of the organic solvent to be added to the coating composition may be appropriately adjusted depending on the concentrations of the polymer and other additives. For example, the amount of the organic solvent added in the range of 45 to 95% by weight in the coating composition. You.

When the composition for forming a protective film contains a crosslinking agent,
The addition amount is not particularly limited, but is preferably 1 to 50 parts by weight, more preferably 5 to 50 parts by weight, based on 100 parts by weight of the polymer.
The range is 40 parts by weight.

When the composition for forming a protective film contains a photopolymerization initiator, the amount thereof is not particularly limited.
The amount is preferably 1 to 50 parts by weight, more preferably 5 to 40 parts by weight based on parts by weight.

When the composition for forming a protective film contains a photosensitive component, the amount thereof is not particularly limited, but is preferably 1 to 50 parts by weight, more preferably 5 to 40 parts by weight, per 100 parts by weight of the polymer. Range.

The composition for forming a protective film used in the method for forming a protective film of the present invention is prepared by dissolving or dispersing each of the above solid components in a solvent component. The order of mixing during preparation is not particularly limited. However, from the viewpoint of the stability of the composition and the like, the composition can be stored in a state of a plurality of solutions, dispersions, or powders, and can be appropriately mixed and used immediately before use. Alternatively, the composition can be prepared in the form of a concentrated solution and diluted with a solvent immediately before use.

<Method for Forming Protective Film> In the method for forming a protective film according to the present invention, the above-described composition for forming a protective film is applied to a substrate to form a film, and the film is heated in an inert gas atmosphere. Is to be cured.

When a thermosetting composition is used In the present invention, when a thermosetting composition is used as a composition for forming a protective film, a protective film is generally formed by the following steps. (A1) a step of applying a composition for forming a protective film on a substrate;
And (a2) a step of heating and curing the applied film of the composition for forming a protective film under an inert gas atmosphere.

The substrate to which the method of forming a protective film of the present invention can be applied includes color filters, glass, glass filters, black matrices, various polymers (polyimide, polyamide, polyethylene, acrylic resin, etc.), indium titanium oxide , Silicon nitride, metal oxides (such as titanium oxide, silicon oxide, and chromium oxide), and metals (such as aluminum and copper), but are not limited thereto.

The method of forming a protective film according to the present invention comprises a step of applying the composition for forming a protective film on the substrate. The method of applying the composition for forming a protective film is not particularly limited, and for example, a method such as a spin coating method, a roll coating method, and a spray method can be used. In particular, the spin coating method is useful for forming a uniform film.

The method of forming a protective film according to the present invention comprises a step of heating the coating of the composition for forming a protective film applied on a substrate in an inert gas atmosphere. The coating can be heated by any method. Specific heating means include a hot plate, a heating furnace, a convection oven, infrared irradiation, and others.

In the protective film forming method of the present invention, the heating conditions of the protective film forming composition may be appropriately determined in consideration of the type of the polymer, the composition of the protective film forming composition, and the like. The heating can be carried out at a temperature of from ℃ to 270 ° C, preferably from 170 to 250 ° C, for about 10 minutes to 10 hours, preferably for 20 minutes to 120 minutes.

In the method for forming a protective film according to the present invention,
The heating is performed under an inert gas atmosphere. In the present invention, the inert gas refers to a gas that does not substantially react with the composition for forming a protective film, and specifically, nitrogen,
Includes argon, helium, neon, xenon, and others, and mixtures thereof. Of these, nitrogen, argon, and a mixed gas thereof are preferable in terms of handling properties and cost.

When a photosensitive composition is used, and when a protective film forming composition to be used is photosensitive,
Generally, a protective film can be formed by the following steps. (B1) a step of applying a composition for forming a protective film on a substrate;
(B2) a step of exposing the applied film of the protective film forming composition, (b3) a step of developing the exposed film, and (b4) heating and curing the developed film in an inert gas atmosphere. Process to make it.

In the case where the photosensitive composition is used as the protective film forming composition, the substrate can be selected from the same ones as in the case where the above-mentioned thermosetting composition is used, and the step (b1) And step (b4) can be performed in the same manner as in the case where the above-mentioned thermosetting composition is used.

When a photosensitive composition is used as the composition for forming a protective film, a polymerization reaction of the components of the composition for forming a protective film can be caused by the exposure step (b2). Light irradiation
In general, imagewise exposure is usually performed so as to expose only a desired portion of a film of the protective film forming composition. However, even when the film of the protective film forming composition is uniformly exposed to light. Good.

The method of exposure can be carried out by a conventional method, and is not particularly limited. For example, a method such as exposure through a photomask or scanning exposure using a stepper or the like is used.

As the light used for the exposure, any radiation can be selected as long as the radiation has a wavelength at which the photosensitive component has sensitivity. Usually, ultraviolet light having a wavelength of 250 to 500 nm is used. The irradiation dose is adjusted so that a sufficient crosslinking reaction occurs in the exposed portion, and is generally in the range of 10 to 500 mJ / cm ² .

The exposed photosensitive resin composition layer is usually developed with an alkali solution in the developing step (b3). When the photosensitive composition is a positive type, a portion of the photosensitive resin composition layer irradiated with actinic radiation is removed by development to obtain a positive image. When the photosensitive composition is of a negative type, the photosensitive resin composition layer may be exposed to actinic radiation, and the non-irradiated portion may be removed to obtain a negative image. it can. As the developing solution, a conventional developing solution used for developing a photoresist can be used. Generally, inorganic alkali compounds, primary amines, secondary amines, tertiary amines, alcohol amines,
Alternatively, an aqueous solution of a quaternary ammonium salt is used. More specifically, tetramethyl ammonium hydride (hereinafter referred to as TMAH), potassium hydroxide, sodium hydroxide, sodium carbonate, sodium silicate, ammonia,
Ethylamine, n-propylamine, diethylamine, diamine
An aqueous solution of -n-propylamine, triethanolamine, dimethylethanolamine, tetramethylammonium, tetraethylammonium, or choline is used. In addition, if necessary, optional additives such as a water-soluble organic solvent (specifically, methanol, ethanol, and others), a surfactant, and others can be added to these developers.

When a photosensitive composition is used as the composition for forming a protective film, preliminary heating can be performed before the exposure step (b2), if necessary. The purpose of this preheating is to remove all or a part of the solvent from the composition for forming a protective film applied on the substrate. As a result, the photosensitive resin composition layer is fixed, and it is possible to prevent the photosensitive resin composition layer from peeling off from the substrate even in the subsequent exposure processing or development processing. The pre-bake treatment can be performed under any conditions as long as the above-mentioned object is achieved.
It can be carried out by heating the photosensitive resin composition layer at 0 ° C. for 30 seconds to 2 minutes.

When a photosensitive composition is used as the composition for forming a protective film, the protective film heat-cured in the step (b4) can be re-exposed. In the method of forming a protective film of the present invention, sufficient transparency can be achieved without performing such re-exposure treatment, but transparency can be further improved by re-exposure.

The substrate on which the protective film is formed by the method of forming a protective film according to the present invention is used for, for example, semiconductors, flat panel displays, and electronic equipment, but is not limited thereto.

The following examples are intended to explain the present invention in more detail, but not to limit the present invention.

[0088]

EXAMPLES Examples 1 to 3 and Comparative Examples 1a to 3b A composition for a photosensitive protective film was prepared from the following components. (Sample A) Polymer: SU007 ^* 18.0% by weight Photosensitizer: 6-diazo-5,6-dihydro- of bis [4-hydroxy-3- (2-hydroxy-5-methylbenzyl) -5-methylphenyl] methane 5-oxonaphthalene-1-sulfonic acid ester 3.6% by weight Solvent: propylene glycol methyl ether 78.4% by weight (Sample B) Polymer: SU007 18.0% by weight Photosensitizer: 4,4 '-[1- [4- [1- 6-diazo-5,6-dihydro-5-oxonaphthalene-1-sulfonate of (4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene] bisphenol 3.6% by weight Solvent: propylene glycol methyl ether 78.4 % By weight (Sample C) Polymer: SU007 18.0% by weight Photosensitizer: 6-diazo-5,6-dihydro of bis [4-hydroxy-3- (2-hydroxy-5-methylbenzyl) -5-methylphenol] methane -5-oxonaphthalene-1-sulfonic acid ester 3.6% by weight Accelerator: 4,4 (2-hydroxyphenyl) methylenebis (2,6-xylenol) 3.0 wt% Solvent: propylene glycol methyl ether 78.4 wt% ^* Clariant Japan K.K. polymer. The monomer composition was, by molar ratio, 13% of methyl methacrylate, 20% of hydroxypropyl methacrylate, 61% of methacrylic acid, and 6% of n-butyl acrylate. Acid value: 85 mgKOH / g, OH value: 78 mgKOH / g, molecular weight: Polymer with properties of 40,000.

Each of the above samples was applied on a glass substrate using a spin coater (1H-DX2 manufactured by Mikasa Corporation) at 700 rpm for 30 seconds. The obtained coated substrate was heated and dried on a hot plate at 90 ° C. for 1 minute. Next, each of the obtained coated substrates is 0.4% TM.
Development was carried out for 1 minute by a dipping method using an AH aqueous solution as a developing solution. Thereafter, the glass substrate having the developed protective film was heated at 250 ° C. for 30 minutes in a heating furnace set in an air atmosphere or a nitrogen atmosphere to cure the coating. For the glass substrate having the obtained protective film, each 400n
m, and the transmittance at 500 nm were measured. The results obtained were as follows.

Air in heating furnace Permeability (%) Permeability (%) Sample atmosphere at 400 nm at 500 nm Example 1 A Nitrogen 78.6 95.6 Comparative Example 1a A Air 63.8 90.0 Example 2 B Nitrogen 87.4 97.1 Comparative Example 2a B Air 58.2 83.6 Example 3 C nitrogen 82.4 97.2 Comparative example 3a C air 60.4 88.6

From these results, it can be seen that according to the method of the present invention, a protective film having high transparency can be produced even when the same composition for a photosensitive protective film is used. In addition, the above Comparative Examples 1 to
In 3, after development and before heat curing, i-line was 200 mJ / cm2.
Exposure, ie, bleaching, was performed under the following conditions. The transmittance of the glass substrate having the obtained protective film was measured. The results obtained were as follows.

[0092]

From the results, it can be seen that according to the method of the present invention, it is possible to produce a protective film having a higher transparency than the bleached one, and it is unnecessary to perform the bleaching step.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) B32B 27/18 B32B 27/18 Z 27/30 27/30 A G03F 7/022 601 G03F 7/022 601 7/38 511 7/38 511 (72) Inventor Junichi Fukuzawa 2-28-8 Honkomagome, Bunkyo-ku, Tokyo Bunkyo Green Court Center Office 9th floor Clariant Japan Co., Ltd. F-term (reference) 2H025 AB17 AB20 AD03 BE01 2H096 AA28 AA30 BA05 BA06 BA09 FA01 FA03 HA03 4D075 BB26X BB42X BB56X EA19 EA45 EB22 EC07 4F100 AH01B AH01H AH04B AH04H AK01B AK24B AK25B AL01B AL05B AR00B AT00A BA02 EH462 EJ422 J41BJNJJB12J12NJJBJB12J

Claims (12)

[Claims] 1. A protective film-forming composition comprising a polymer and a solvent is applied to a substrate to form a film, and the film is cured by heating to form a protective film on the substrate. A method for forming a protective film, wherein the heating is performed in an inert gas atmosphere. 2. The method according to claim 1, wherein the composition is a thermosetting composition. 3. The method according to claim 1, wherein the polymer is a polymer having a carboxyl group. 4. The method according to claim 1, wherein the composition is a photosensitive composition, and the applied film is exposed before heating. 5. The method according to claim 4, wherein the photosensitive composition is a negative photosensitive composition. 6. The method according to claim 5, wherein the polymer is represented by the following general formula (III). Embedded image 7. The method according to claim 4, wherein the photosensitive composition is a positive photosensitive composition. 8. The photosensitive composition according to claim 1, wherein said photosensitive component has the following general formulas (Va) to (Va):
The method for forming a protective film according to claim 7, wherein the method is at least one kind selected from the group consisting of c). Embedded image 9. The method according to claim 4, wherein the coating after heating is re-exposed.
The method for forming a protective film according to any one of the above items. 10. The method according to claim 1, wherein the substrate is a display portion of an optical device. 11. The method for forming a protective film according to claim 1, wherein the inert gas is a gas selected from the group consisting of nitrogen, argon, and a mixture thereof. 12. An article, wherein a protective film is formed by the method according to any one of claims 1 to 11.