JP2006184841A - Photosensitive resin composition, spacer for display panel and display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition solution for spacer formation giving an even film uniform in thickness and suitable for a slit die coater method in which a reduced-pressure drying step is carried out in a short time. <P>SOLUTION: The photosensitive resin composition comprises (A) a copolymer of at least one selected from the group consisting of ethylenically unsaturated carboxylic acids and ethylenically unsaturated carboxylic acid anhydrides, an epoxy group-containing ethylenically unsaturated compound, and another ethylenically unsaturated compound different from those, (B) a polymerizable compound having an ethylenically unsaturated bond, and (C) a photopolymerization initiator, wherein a solid concentration X (wt.%) and a viscosity Y (mPa s) at 25°C satisfy relationships of LogY≤0.04X-0.08 (1), LogY≥0.04X-0.50 (2), LogY≥0.30 (3) and LogY≤1.08 (4). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photosensitive resin composition, a display panel spacer, and a display panel. More specifically, a photosensitive resin composition suitable as a material for forming a spacer used in a display panel such as a liquid crystal display panel or a touch panel, a display panel spacer formed from the composition, and the spacer. It relates to a display panel.

Conventionally, liquid crystal display panels use spacer particles such as glass beads and plastic beads having a predetermined particle size in order to keep the distance (cell gap) between two substrates constant. Since the particles are randomly distributed on a transparent substrate such as a glass substrate, the presence of spacer particles in the pixel formation region causes a reflection phenomenon of the spacer particles, the incident light is scattered, and the contrast of the liquid crystal panel is reduced. There was a problem of lowering.
In order to solve these problems, a method of forming a spacer by photolithography has been adopted. In this method, a photosensitive resin composition is applied onto a substrate, exposed to ultraviolet rays through a predetermined mask, and then developed to form dot-like or stripe-like spacers. Since the spacer can be formed only at a predetermined place, the above-described problem is basically solved. Further, according to this method, there is an advantage that the cell gap width can be easily controlled by controlling the coating film thickness of the photosensitive resin composition.

  By the way, in the manufacture of a liquid crystal display panel, the substrate size has been increased from the viewpoint of improving productivity and adapting to a large screen. The first generation of 300 mm x 400 mm, the second generation of 370 mm x 470 mm, the third generation of 620 mm x 750 mm, the fourth generation of 960 mm x 1100 mm, and the fifth generation of 1100 mm x 1300 mm are now mainstream. ing. Further, the sixth generation of 1500 mm × 1850 mm and the seventh generation of 1850 mm × 2100 mm and the substrate size will be further increased in the future.

When the substrate size is small, for example, 370 mm × 470 mm or less, the photosensitive resin composition is dropped onto the substrate in the center and applied by a spin coating method. This method has a drawback that a large amount of the photosensitive resin composition solution is required for coating, and it cannot be applied to a large substrate.
When the substrate size is 960 mm × 1100 mm or less, the coating is performed by the slit & spin method for the purpose of saving the photosensitive resin composition solution. In this method, a photosensitive resin composition solution is applied to a substrate surface from a slit nozzle, and then the substrate is rotated to form a uniform coating film. This method is effective for saving liquid, but it is difficult to cope with the substrate size from the fifth generation onward.

From such a background, as the substrate size increases, coating by a slit die coater has been performed. However, in the case of a slit die coater, it is important to control the viscosity and solid content concentration (TSC) of the photosensitive resin composition solution in order to obtain a good coating film. If the viscosity and TSC are too high, liquid leakage from the slit nozzle occurs and streaky unevenness occurs. On the other hand, if the viscosity is too low, the film thickness at the edge of the substrate becomes non-uniform. If the TSC is low, the liquid concentration in the photosensitive resin composition solution increases, so that the required time becomes longer in the reduced-pressure drying step after the coating step. An increase in the vacuum drying process time is undesirable from the viewpoint of improving productivity.
For these reasons, in the slit die coater method, a photosensitive resin composition solution for forming a spacer that has a uniform film thickness, no unevenness, and a short time for a drying process under reduced pressure has been strongly desired.

  Accordingly, an object of the present invention is to provide a photosensitive resin composition solution for forming a spacer suitable for a slit die coater method having a uniform film thickness, no unevenness, and a short vacuum drying process time.

According to the present invention, the problem is firstly
[A] (a1) at least one selected from the group consisting of ethylenically unsaturated carboxylic acids and ethylenically unsaturated carboxylic acid anhydrides, (a2) an epoxy group-containing ethylenically unsaturated compound, and (a3) (a1) And a copolymer with another ethylenically unsaturated compound different from (a2),
[B] A polymerizable compound having an ethylenically unsaturated bond and [C] a photopolymerization initiator, and having a solid content concentration and a viscosity at 25 ° C. of the following formulas (1) to (4):
LogY ≦ 0.04X−0.08 (1)
LogY ≧ 0.04X−0.50 (2)
LogY ≧ 0.30 (3)
LogY ≦ 1.08 (4)
Where X is the solids concentration (wt%) and Y is the viscosity (mPa · s) at 25 ° C.
Satisfy the relationship
This is achieved by a photosensitive resin composition (hereinafter referred to as “photosensitive resin composition (A)”).

  According to the present invention, secondly, the above object is achieved by a display panel spacer formed from the photosensitive resin composition (a).

  According to the present invention, thirdly, the object is achieved by a display panel comprising the display panel spacer.

  The photosensitive resin composition (A) of the present invention has no problem with respect to safety to living organisms, has good coating properties even on a large substrate, and can faithfully reproduce the design size of a mask pattern with high sensitivity. The present invention also provides a photosensitive resin composition that can form a display panel spacer that is excellent in adhesion to a substrate and that is excellent in strength, heat resistance, and the like.

Hereinafter, the present invention will be described in detail.
Photosensitive resin composition (I)
-Copolymer [A]-
The component [A] in the photosensitive resin composition (A) includes (a1) an ethylenically unsaturated carboxylic acid and / or an ethylenically unsaturated carboxylic acid anhydride, (a2) an epoxy group-containing ethylenically unsaturated compound, and (a3 And (a1) component and (a2) component and a copolymer with another ethylenically unsaturated compound (hereinafter referred to as “copolymer [A]”).
Among the components constituting the copolymer [A], (a1) an ethylenically unsaturated carboxylic acid and / or an ethylenically unsaturated carboxylic acid anhydride (hereinafter referred to as “unsaturated carboxylic acid monomer”) Examples of (a1) ”include monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyethyl hexahydrophthalic acid; maleic acid, fumaric acid Examples thereof include dicarboxylic acids such as acid, citraconic acid, mesaconic acid, and itaconic acid; anhydrides of the dicarboxylic acid.
Among these unsaturated carboxylic acid monomers (a1), acrylic acid, methacrylic acid, maleic anhydride are available from the viewpoints of copolymerization reactivity, solubility of the resulting copolymer in an alkaline aqueous solution and easy availability. Etc. are preferred.
In the photosensitive resin composition (a), the unsaturated carboxylic acid monomer (a1) can be used alone or in combination of two or more.

  In the copolymer [A], the content of the repeating unit derived from the unsaturated carboxylic acid monomer (a1) is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, and particularly preferably 15%. ~ 30% by weight. In this case, when the content of the repeating unit derived from the unsaturated carboxylic acid monomer (a1) is less than 5% by weight, the solubility in an alkaline aqueous solution tends to decrease, whereas when it exceeds 40% by weight. There is a possibility that the solubility in an aqueous alkali solution becomes too large.

Examples of the (a2) epoxy group-containing ethylenically unsaturated compound (hereinafter referred to as “epoxy group-containing monomer (a2)”) include, for example, glycidyl acrylate, 2-methylglycidyl acrylate, 3, 4-epoxybutyl, acrylic acid epoxy alkyl ester such as 6,7-epoxyheptyl acrylate, 3,4-epoxycyclohexyl acrylate; glycidyl methacrylate, 2-methylglycidyl methacrylate, 3,4-epoxybutyl methacrylate, Methacrylic acid epoxy alkyl esters such as 6,7-epoxyheptyl methacrylate, 3,4-epoxycyclohexyl methacrylate; glycidyl α-ethyl acrylate, glycidyl α-n-propyl acrylate, glycidyl α-n-butyl acrylate, α-ethylacrylic acid , 7-epoxy heptyl, such as α- alkyl acrylate epoxy alkyl ester; can be exemplified o- vinylbenzyl glycidyl ether, m- vinylbenzyl glycidyl ether, such as glycidyl ethers of p- vinylbenzyl glycidyl ether.
Among these epoxy group-containing monomers (a2), from the viewpoint of copolymerization reactivity and spacer strength, glycidyl methacrylate, 2-methylglycidyl methacrylate, 6,7-epoxyheptyl methacrylate, o-vinylbenzyl Glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether and the like are preferable.
In the photosensitive resin composition (I), the epoxy group-containing monomer (a2) can be used alone or in admixture of two or more.

  In the copolymer [A], the content of the repeating unit derived from the epoxy group-containing monomer (a2) is preferably 10 to 70% by weight, more preferably 20 to 60% by weight, and particularly preferably 30 to 50%. % By weight. In this case, when the content of the repeating unit derived from the epoxy group-containing monomer (a2) is less than 10% by weight, the strength of the obtained spacer tends to be reduced, while when it exceeds 70% by weight, There is a tendency for the storage stability of the copolymer to be reduced.

Furthermore, (a3) other ethylenically unsaturated compounds (hereinafter simply referred to as “other monomers (a3)”) include, for example, alkyl acrylates such as methyl acrylate and i-propyl acrylate; Methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate; cyclohexyl acrylate, 2-methylcyclohexyl acrylate, tricycloacrylate [5.2 .1.0 ^2,6 ] decan-8-yl, acrylic acid alicyclic such as 2- (tricyclo [5.2.1.0 ^2,6 ] decan-8-yloxy) ethyl, isobornyl acrylate. Esters: cyclohexyl methacrylate, 2-methylcyclohexyl methacrylate, methacrylic acid Rishikuro [5.2.1.0 ^2,6] decan-8-yl methacrylate, 2 (tricyclo [5.2.1.0 ^2,6] decan-8-yloxy) ethyl, such as methacrylic acid isobornyl Methacrylic acid alicyclic ester; aryl ester or aralkyl ester of acrylic acid such as phenyl acrylate and benzyl acrylate; aryl ester or aralkyl ester of methacrylic acid such as phenyl methacrylate and benzyl methacrylate; diethyl maleate, diethyl fumarate Dicarboxylic acid dialkyl esters such as diethyl itaconate; 2-hydroxyethyl methacrylate, methacrylic acid hydroxyalkyl esters such as 2-hydroxypropyl methacrylate; tetrahydrofurfuryl methacrylate, tetrahydride methacrylate Unsaturated hetero 5- and 6-membered methacrylic acid esters containing one atom of oxygen such as furyl, tetrahydrofupyran-2-methyl methacrylate; styrene, α-methyl styrene, m-methyl styrene, p-methyl styrene, p-methoxy Vinyl aromatic compounds such as styrene; conjugated diene compounds such as 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl chloride, Examples include vinylidene chloride and vinyl acetate.

Among these other monomers (a3), from the viewpoint of copolymerization reactivity and solubility of the resulting copolymer in an alkaline aqueous solution, 2-methylcyclohexyl acrylate, t-butyl methacrylate, tricyclomethacrylate [ 5.2.1.0 ^2,6 ] Decan-8-yl, styrene, p-methoxystyrene, tetrahydrofurfuryl methacrylate, 1,3-butadiene and the like are preferable. In particular, when 1,3-butadiene is used, a more excellent developability is obtained, which is more preferable.

  In the photosensitive resin composition (A), the other monomer (a3) can be used alone or in admixture of two or more.

  In the copolymer [A], the content of the repeating unit derived from the other monomer (a3) is preferably 10 to 70% by weight, more preferably 20 to 50% by weight, particularly preferably 30 to 50% by weight. %. In this case, if the content of the repeating unit derived from the other monomer (a3) is less than 10% by weight, the storage stability of the resulting copolymer tends to be lowered, whereas it exceeds 70% by weight. And there exists a tendency for the solubility with respect to the aqueous alkali solution of the copolymer obtained to fall.

  The copolymer [A] has a carboxyl group and / or a carboxylic anhydride group and an epoxy group, has an appropriate solubility in an alkaline aqueous solution, and does not require the use of a special curing agent. It can be easily cured by heating. Therefore, the photosensitive resin composition (a) containing the copolymer can easily form a spacer having a predetermined pattern without developing residue and film loss during development.

For example, the copolymer [A] is obtained by starting radical polymerization of an unsaturated carboxylic acid monomer (a1), an epoxy group-containing monomer (a2), and another monomer (a3) in an appropriate solvent. It can manufacture by superposing | polymerizing in presence of an agent.
Examples of the solvent used for the production of the copolymer [A] include alcohol, ether, glycol ether, ethylene glycol alkyl ether acetate, diethylene glycol, dipropylene glycol, propylene glycol monoalkyl ether, propylene glycol alkyl ether acetate, and propylene glycol. Examples include alkyl ether propionates, aromatic hydrocarbons, ketones and esters.

Specific examples thereof include alcohols such as methanol, ethanol, benzyl alcohol, 2-phenylethyl alcohol, and 3-phenyl-1-propanol;
Ethers such as tetrahydrofuran;
Examples of glycol ethers include ethylene glycol monomethyl ether and ethylene glycol monoethyl ether;
Examples of ethylene glycol alkyl ether acetate include methyl cellosolve acetate, ethyl cellosolve acetate, ethylene glycol monobutyl ether acetate, and ethylene glycol monoethyl ether acetate;
Examples of diethylene glycol include diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol ethyl methyl ether.
Examples of dipropylene glycol include dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, and dipropylene glycol ethyl methyl ether;
Examples of propylene glycol monoalkyl ethers include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether;
As propylene glycol alkyl ether propionate, for example, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, propylene glycol butyl ether acetate and the like;
As propylene glycol alkyl ether acetate, for example, propylene glycol methyl ether propionate, propylene glycol ethyl ether propionate, propylene glycol propyl ether propionate, propylene glycol butyl ether propionate, etc .;
Aromatic hydrocarbons such as toluene, xylene, etc .;
Examples of ketones include methyl ethyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, etc .;

Examples of esters include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, methyl hydroxyacetate, hydroxy Ethyl acetate, hydroxybutyl acetate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, methyl 3-hydroxypropionate, ethyl 3-hydroxypropionate, propyl 3-hydroxypropionate, butyl 3-hydroxypropionate, 2-hydroxy -3-methylbutanoate, methyl methoxyacetate, ethyl methoxyacetate, propyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, propyl ethoxyacetate, butyl ethoxyacetate, propoxy Methyl acetate, ethyl propoxyacetate, propyl propoxyacetate, butyl propoxyacetate, methyl butoxyacetate, ethyl butoxyacetate, propyl butoxyacetate, butylbutoxyacetate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate, 2-methoxypropionic acid Propyl, butyl 2-methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate, propyl 2-ethoxypropionate, butyl 2-ethoxypropionate, methyl 2-butoxypropionate, ethyl 2-butoxypropionate Propyl 2-butoxypropionate, butyl 2-butoxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, 3-methoxypropyl Butyl pionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, propyl 3-ethoxypropionate, butyl 3-ethoxypropionate, methyl 3-propoxypropionate, ethyl 3-propoxypropionate, 3-propoxypropionate Examples thereof include esters such as propyl acid, butyl 3-propoxypropionate, methyl 3-butoxypropionate, ethyl 3-butoxypropionate, propyl 3-butoxypropionate, and butyl 3-butoxypropionate.

Of these, ethylene glycol alkyl ether acetate, diethylene glycol, dipropylene glycol, propylene glycol monoalkyl ether, and propylene glycol alkyl ether acetate are preferable. Among them, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, dipropylene glycol dimethyl ether, dipropylene glycol ethyl Particularly preferred are methyl ether, propylene glycol methyl ether, and propylene glycol methyl ether acetate.
The said solvent can be used individually or in mixture of 2 or more types.

The radical polymerization initiator used for the polymerization is not particularly limited, and for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis- (2,4-dimethylvalero). Nitrile), 2,2′-azobis- (4-methoxy-2,4-dimethylvaleronitrile), 4,4′-azobis (4-cyanovaleric acid), dimethyl 2,2′-azobis (2-methylpro) Azo compounds such as 2,7'-azobis (4-methoxy-2,4-dimethylvaleronitrile); benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, 1,1-bis (t-butyl) Organic peroxides such as peroxy) cyclohexane; hydrogen peroxide and the like. Moreover, when using a peroxide as a radical polymerization initiator, it is good also as a redox type initiator combining it and a reducing agent.
These radical polymerization initiators can be used alone or in admixture of two or more.
The copolymer [A] thus obtained may be used for the preparation of the radiation-sensitive resin composition in the form of a solution, or may be separated from the solution and used for the preparation of the radiation-sensitive resin composition. .

  The polystyrene-converted weight average molecular weight (hereinafter referred to as “Mw”) of the copolymer [A] by gel permeation chromatography (GPC) is preferably 2,000 to 100,000, more preferably 5,000 to 50, 000, particularly preferably 1,000 to 10,000. In this case, if the Mw is less than 2,000, the developability and the remaining film rate of the resulting film may be reduced, and the pattern shape, heat resistance, and the like may be impaired. There exists a possibility that applicability | paintability may deteriorate or developability may be impaired.

-Polymerizable compound [B]-
The component [B] in the photosensitive resin composition (A) is a polymerizable compound having an ethylenically unsaturated bond (hereinafter referred to as “polymerizable compound [B]”).
Although it does not specifically limit as polymeric compound [B], Monofunctional, bifunctional, or trifunctional or more (meth) acrylic acid ester has good polymerizability, and the strength of the spacer obtained is improved. This is preferable.

  Examples of the monofunctional (meth) acrylic acid ester include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, diethylene glycol monoethyl ether acrylate, diethylene glycol monoethyl ether methacrylate, isobornyl acrylate, isobornyl methacrylate, 3- Examples include methoxybutyl acrylate, 3-methoxybutyl methacrylate, 2-acryloyloxyethyl-2-hydroxypropyl phthalate, and 2-methacryloyloxyethyl-2-hydroxypropyl phthalate. As commercial products, for example, Aronix M-101, M-111, M-114 (manufactured by Toa Gosei Co., Ltd.); KAYARAD TC-110S, TC-120S (manufactured by Nippon Kayaku Co., Ltd.); 158, 2311 (manufactured by Osaka Organic Chemical Industry Co., Ltd.).

  Examples of the bifunctional (meth) acrylic acid ester include ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, 1,6- Examples include hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol diacrylate, 1,9-nonanediol dimethacrylate, bisphenoxyethanol full orange acrylate, and bisphenoxyethanol full orange methacrylate. As commercially available products, for example, Aronix M-210, M-240, M-6200 (manufactured by Toa Gosei Co., Ltd.), KAYARAD HDDA, HX-220, R-604 (manufactured by Nippon Kayaku Co., Ltd.) ), Biscoat 260, 312 and 335HP (produced by Osaka Organic Chemical Industry Co., Ltd.).

Furthermore, as the trifunctional or higher functional (meth) acrylic acid ester, for example, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, Dipentaerythritol pentaacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, tri (2-acryloyloxyethyl) phosphate, tri (2-methacryloyloxyethyl) phosphate, etc. it can.
In particular, the (meth) acrylate having 9 or more functional groups includes a compound having an alkylene linear and alicyclic structure and containing two or more isocyanate groups, and a trifunctional or tetrafunctional containing one or more hydroxyl groups in the molecule. And urethane acrylate compounds obtained by reacting pentafunctional (meth) acrylate compounds.
As said commercial item, for example, Aronix M-309, M-400, M-405, M-450, M-7100, M-8030, M-8060, M-8060, TO-1450 (Toa Gosei ( KAYARAD TMPTA, DPHA, DPCA-20, DPCA-30, DPCA-60, DPCA-60, DPCA-120 (manufactured by Nippon Kayaku Co., Ltd.), Biscote 295, 300, 360, GPT, 3PA, 400 (produced by Osaka Organic Chemical Industry Co., Ltd.) and the like. Examples of commercially available products of polyfunctional urethane acrylates having 9 or more functional groups include New Frontier R-1150 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), KAYARAD DPHA-40H (manufactured by Nippon Kayaku Co., Ltd.) Is mentioned.

Among these monofunctional, bifunctional, or trifunctional or higher (meth) acrylic acid esters, trifunctional or higher functional (meth) acrylic acid esters are more preferable, and in particular, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol. Tetraacrylate, dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate are preferred.
The monofunctional, bifunctional, or trifunctional or higher (meth) acrylic acid ester can be used alone or in combination of two or more.

  In the photosensitive resin composition (A), the amount of the polymerizable compound [B] used is preferably 50 to 250 parts by weight, more preferably 100 to 200 parts by weight, relative to 100 parts by weight of the copolymer [A]. It is. In this case, if the amount of the polymerizable compound [B] used is less than 50 parts by weight, there is a possibility that a development residue may occur during development. On the other hand, if it exceeds 200 parts by weight, the adhesion of the resulting spacer tends to decrease. .

-Photopolymerization initiator [C]-
The photopolymerization initiator referred to in the present invention generates an active species capable of initiating polymerization of the polymerizable compound [B] when exposed to visible light, ultraviolet light, far ultraviolet light, charged particle beam, X-ray or the like. Means ingredients.
The amount of the photopolymerization initiator [C] used in the photosensitive resin composition (a) is preferably 5 to 30 parts by weight, more preferably 5 to 20 parts by weight, based on 100 parts by weight of the polymerizable compound [B]. It is. In this case, if the amount of the photopolymerization initiator [C] used is less than 5 parts by weight, the residual film ratio during development tends to decrease. On the other hand, if it exceeds 30 parts by weight, an alkaline developer in an unexposed part during development. There is a tendency for the solubility to be reduced.
In the photosensitive resin composition (A), at least one other photopolymerization initiator can be used in combination with the photopolymerization initiator [C].

  Examples of the photopolymerization initiator [C] include O-acyl oxime ester compounds, biimidazole compounds, benzoin compounds, acetophenone compounds, benzophenone compounds, α-diketone compounds, polynuclear quinone compounds, xanthone compounds. , Phosphine compounds, triazine compounds, and the like.

  Specific examples of O-acyloxime ester compounds include 1- [9-ethyl-6-benzoyl-9.H.-carbazol-3-yl] -nonane-1,2-nonane-2-oxime-O—. Benzoate, 1- [9-ethyl-6-benzoyl-9.H.-carbazol-3-yl] -nonane-1,2-nonane-2-oxime-O-acetate, 1- [9-ethyl-6 -Benzoyl-9.H.-carbazol-3-yl] -pentane-1,2-pentane-2-oxime-O-acetate, 1- [9-ethyl-6-benzoyl-9.H.-carbazole-3 -Yl] -octane-1-one oxime-O-acetate, 1- [9-ethyl-6- (2-methylbenzoyl) -9.H.-carbazol-3-yl] -ethane-1-one oxime-O- Benzoate, 1- [9-ethyl-6- ( 2-Methylbenzoyl) -9.H.-carbazol-3-yl] -ethane-1-one oxime-O-acetate, 1- [9-ethyl-6- (1,3,5-trimethylbenzoyl) -9. H.-Carbazol-3-yl] -ethane-1-one oxime-O-benzoate, 1- [9-butyl-6- (2-ethylbenzoyl) -9.H.-carbazol-3-yl] -ethane Examples include -1-one oxime-O-benzoate. In addition, 1,2-octadion-1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime), 1,2-butanedione-1- [4- (phenylthio) phenyl] -2- (O— Benzoyloxime), 1,2-butanedione-1- [4- (phenylthio) phenyl] -2- (O-acetyloxime), 1,2-octadion-1- [4- (methylthio) phenyl] -2- ( O-benzoyloxime), 1,2-octadion-1- [4- (phenylthio) phenyl] -2- (O- (4-methylbenzoyloxime)) and the like.

Of these, 1- [9-ethyl-6- (2-methylbenzoyl) -9.H.-carbazol-3-yl] -ethane-1-one oxime-O-acetate, 1,2-octadione-1 -[4- (Phenylthio) phenyl] -2- (O-benzoyloxime) is preferred. Two or more of these photopolymerization initiators may be used at the same time.
By using these photopolymerization initiators, it is possible to obtain a spacer having good sensitivity and adhesion.

  Examples of the acetophenone compounds include α-hydroxy ketone compounds, α-amino ketone compounds, and other compounds.

Specific examples of the α-hydroxyketone compound include 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1- (4-i-propylphenyl) -2-hydroxy-2-methylpropane- 1-one, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenyl ketone and the like can be mentioned, and specific examples of the α-aminoketone compound include: 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2- (4 -Methylbenzyl) -2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 and the like, and other compounds Specific examples of the product include 2,2-dimethoxyacetophenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, and the like.
These acetophenone compounds can be used alone or in admixture of two or more.
By using these acetophenone compounds, it is possible to further improve sensitivity, spacer shape and compressive strength.

As a specific example of the biimidazole compound,
2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetrakis (4-ethoxycarbonylphenyl) -1,2′-biimidazole,
2,2′-bis (2-bromophenyl) -4,4 ′, 5,5′-tetrakis (4-ethoxycarbonylphenyl) -1,2′-biimidazole,
2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole,
2,2′-bis (2,4-dichlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole,
2,2′-bis (2,4,6-trichlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole,
2,2′-bis (2-bromophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole,
2,2′-bis (2,4-dibromophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole,
Examples include 2,2′-bis (2,4,6-tribromophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole.

Among the biimidazole compounds, 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole, 2,2′-bis (2, 4-dichlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole, 2,2′-bis (2,4,6-trichlorophenyl) -4,4 ′, 5 5′-tetraphenyl-1,2′-biimidazole and the like are preferable, and 2,2′-bis (2,4-dichlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1, is particularly preferable. 2'-biimidazole.
The biimidazole compounds can be used alone or in admixture of two or more.
By using these biimidazole compounds, sensitivity, resolution, and adhesion can be further improved.

Moreover, in order to sensitize a biimidazole compound, the aliphatic or aromatic compound which has a dialkylamino group can be used.
Specific examples of the sensitizer include, for example, N-methyldiethanolamine, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone, ethyl p-dimethylaminobenzoate, p- Examples thereof include i-amyl dimethylaminobenzoate. Of these sensitizers, 4,4′-bis (diethylamino) benzophenone is preferred.
Two or more of these sensitizers may be used at the same time.
The amount of the sensitizer used is preferably 0.1 to 50 parts by weight, more preferably 1 to 20 parts by weight with respect to 100 parts by weight of [A].
If the amount of the sensitizer is less than 0.1 parts by weight, the resulting spacer tends to cause film slippage or poor pattern shape, and if it exceeds 50 parts by weight, it also tends to cause pattern shape defects. is there.

When a biimidazole compound is used, a thiol compound can be used as the hydrogen donor compound. The biimidazole compound is sensitized by a benzophenone compound having a dialkylamino group, and the biimidazole compound is cleaved to generate an imidazole radical. In this case, a high radical polymerization initiating ability is not expressed, and an unfavorable shape such as a reverse taper shape is often obtained. This problem is alleviated by adding the thiol compound [C-5] to a system in which a biimidazole compound and a benzophenone compound having a dialkylamino group coexist. A hydrogen radical is donated from the thiol compound to the imidazole radical, thereby generating a compound having a neutral imidazole and a sulfur radical having a high polymerization initiating ability. Thereby, it becomes a more preferable forward taper shape from a reverse taper shape.
The use ratio of the thiol compound is preferably 0.1 to 50 parts by weight, more preferably 1 to 20 parts by weight with respect to 100 parts by weight of the compound [A]. When the amount of the thiol compound is less than 0.1 part by weight, the resulting spacer tends to cause film slippage or poor pattern shape. When the amount exceeds 50 parts by weight, the pattern shape defect tends to occur similarly. is there.
Specific examples thereof include aromatic thiols such as 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-5-methoxybenzothiazole, 2-mercapto-5-methoxybenzimidazole, 3 -Aliphatic monothiols such as mercaptopropionic acid, methyl 3-mercaptopropionate, ethyl 3-mercaptopropionate and octyl 3-mercaptopropionate. Examples of the bifunctional or higher aliphatic thiol include 3,6-dioxa-1,8-octanedithiol, pentaerythritol tetra (mercaptoacetate), pentaerythritol tetra (3-mercaptopropionate), and the like.

-Additives-
In the photosensitive resin composition (A), additives other than the above components can be blended as necessary within the range not impairing the intended effect of the present invention.
For example, in order to improve applicability, a surfactant can be blended. As the surfactant, a fluorine-based surfactant and a silicone-based surfactant can be suitably used.

  As the fluorosurfactant, a compound having a fluoroalkyl or fluoroalkylene group in at least one of the terminal, main chain and side chain can be suitably used. Specific examples thereof include 1,1,2 , 2-tetrafluorooctyl (1,1,2,2-tetrafluoropropyl) ether, 1,1,2,2-tetrafluorooctyl hexyl ether, octaethylene glycol di (1,1,2,2-tetrafluoro) Butyl) 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-hexafluoropentyl) ether, sodium perfluorododecyl sulfonate, 1,1,2,2,8,8,9,9,1 , 10-decafluorododecane, 1,1,2,2,3,3-hexafluorodecane, sodium fluoroalkylbenzenesulfonate, sodium fluoroalkylphosphonate, sodium fluoroalkylcarboxylate, fluoroalkylpolyoxyethylene ether, diglycerin Examples thereof include tetrakis (fluoroalkyl polyoxyethylene ether), fluoroalkyl ammonium iodide, fluoroalkyl betaine, fluoroalkyl polyoxyethylene ether, perfluoroalkyl polyoxyethanol, perfluoroalkyl alkoxylate, and fluorine-based alkyl ester. .

Examples of these commercially available products include BM-1000, BM-1100 (manufactured by BM CHEMIE), MegaFuck F142D, F172, F173, F183, F178, F191, F191, F471, and F476. (Above, manufactured by Dainippon Ink & Chemicals, Inc.), Florard FC 170C, FC-171, FC-430, FC-431 (above, manufactured by Sumitomo 3M), Surflon S-112, S-113, S-131, S-141, S-145, S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 ( Asahi Glass Co., Ltd.), Ftop EF301, 303, 352 (above, Shin-Akita Kasei Co., Ltd.), Footent FT-100, FT-11 FT-140A, FT-150, FT-250, FT-251, FTX-251, FTX-218, FT-300, FT-310, FT-400S ) Manufactured by Neos).
Examples of the silicone-based surfactant include Torre Silicone DC3PA, DC7PA, SH11PA, SH21PA, SH28PA, SH29PA, SH30PA, SH-190, SH-193, SZ-6032, SF -8428, DC-57, DC-190 (above, manufactured by Toray Dow Corning Silicone Co., Ltd.), TSF-4440, TSF-4300, TSF-4445, TSF-4446, TSF-4460, TSF-4442 (The above-mentioned, GE Toshiba Silicone Co., Ltd. product) etc. can be mentioned what is marketed.

Examples of surfactants other than the above include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether; polyoxyethylene n-octylphenyl ether, polyoxy Polyoxyethylene aryl ethers such as ethylene n-nonylphenyl ether; nonionic surfactants such as polyoxyethylene dialkyl esters such as polyoxyethylene dilaurate and polyoxyethylene distearate, and commercially available products such as KP341 (Shin-Etsu) Chemical Industry Co., Ltd.), Polyflow No. 57, 95 (manufactured by Kyoeisha Yushi Chemical Co., Ltd.) and the like.
These surfactants can be used alone or in admixture of two or more.

The blending amount of the surfactant is preferably 5 parts by weight or less, and more preferably 2 parts by weight or less with respect to 100 parts by weight of the copolymer [A]. In this case, when the compounding amount of the surfactant exceeds 5 parts by weight, there is a tendency that film roughening is likely to occur during coating.
Moreover, in order to further improve the adhesion to the substrate, an adhesion assistant can be blended.

As the adhesion aid, a functional silane coupling agent is preferable, and examples thereof include a silane coupling agent having a reactive functional group such as a carboxyl group, a methacryloyl group, an isocyanate group, and an epoxy group. More specifically, trimethoxysilylbenzoic acid, γ-methacryloyloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and the like can be mentioned.
These adhesion assistants can be used alone or in admixture of two or more.

  The compounding amount of the adhesion assistant is preferably 20 parts by weight or less, more preferably 10 parts by weight or less with respect to 100 parts by weight of the copolymer [A]. In this case, when the blending amount of the adhesion assistant exceeds 20 parts by weight, there is a tendency that a development residue is likely to occur.

  Other additives can be added. It is added for the purpose of improving storage stability. Specific examples include sulfur, quinones, hydroquinones, polyoxy compounds, amines, and nitronitroso compounds. Examples thereof include 4-methoxyphenol and N-nitroso-N-phenylhydroxylamine aluminum. These are preferably used in an amount of 3.0 parts by weight or less, more preferably 0.001 to 0.5 parts by weight with respect to 100 parts by weight of the copolymer [A]. When the amount exceeds 3.0 parts by weight, sufficient sensitivity cannot be obtained, and the pattern shape deteriorates.

In order to improve heat resistance, an N- (alkoxymethyl) glycoluril compound, an N- (alkoxymethyl) melamine compound, and a compound having a bifunctional or higher functional epoxy group in one molecule can be added. Specific examples of the N- (alkoxymethyl) glycoluril compound include N, N, N, N-tetra (methoxymethyl) glycoluril, N, N, N, N-tetra (ethoxymethyl) glycoluril, N, N, N, N-tetra (n-propoxymethyl) glycoluril, N, N, N, N-tetra (i-propoxymethyl) glycoluril, N, N, N, N-tetra (n-butoxymethyl) glycol Examples include uril, N, N, N, N-tetra (t-butoxymethyl) glycoluril and the like. Of these, N, N, N, N-tetra (methoxymethyl) glycoluril is particularly preferable. Specific examples of the N- (alkoxymethyl) melamine compound include N, N, N, N, N, N-hexa (methoxymethyl) melamine, N, N, N, N, N, N-hexa (ethoxymethyl). ) Melamine, N, N, N, N, N, N-hexa (n-propoxymethyl) melamine, N, N, N, N, N, N-hexa (i-propoxymethyl) melamine, N, N, N , N, N, N-hexa (n-butoxymethyl) melamine, N, N, N, N, N, N-hexa (t-butoxymethyl) melamine and the like. Of these, N, N, N, N, N, N-hexa (methoxymethyl) melamine is particularly preferable. Examples of these commercially available products include Nicalac N-2702, MW-30M (manufactured by Sanwa Chemical Co., Ltd.) and the like.
Examples of the compound having a bifunctional or higher functional epoxy group in one molecule include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, and polypropylene glycol diglycidyl. Examples include ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, hydrogenated bisphenol A diglycidyl ether, and bisphenol A diglycidyl ether. Specific examples of these commercially available products include Epolite 40E, Epolite 100E, Epolite 200E, Epolite 70P, Epolite 200P, Epolite 400P, Epolite 40E, Epolite 1500NP, Epolite 1600, Epolite 80MF, Epolite 100MF, Epolite 4000, Epolite 3002 (and more) Chemical Co., Ltd.). These can be used alone or in combination of two or more.

Composition solution The photosensitive resin composition (A) is usually dissolved in a suitable solvent with constituent components such as a copolymer [A], a polymerizable compound [B], and a photopolymerization initiator [C]. Then, it is prepared as a composition solution.
As a solvent used for the preparation of the composition solution, a solvent that uniformly dissolves each component constituting the photosensitive resin composition (A) and does not react with each component is used.
As such a solvent, the thing similar to what was illustrated as a solvent which can be used in order to manufacture copolymer [A] mentioned above can be mentioned.

  Of these solvents, alcohols, glycol ethers, ethylene glycol alkyl ether acetates, esters and diethylene glycol are preferably used from the viewpoints of solubility of each component, reactivity with each component, ease of film formation, and the like. It is done. Among these, for example, benzyl alcohol, 2-phenylethyl alcohol, 3-phenyl-1-propanol, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether Propylene glycol monomethyl ether acetate, methyl methoxypropionate, and ethyl ethoxypropionate can be particularly preferably used.

  Furthermore, in order to improve the in-plane uniformity of the film thickness together with the solvent, a high boiling point solvent can be used in combination. Examples of the high boiling point solvent that can be used in combination include N-methylformamide, N, N-dimethylformamide, N-methylformanilide, N-methylacetamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, and benzylethyl ether. , Dihexyl ether, acetonyl acetone, isophorone, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, phenyl Examples include cellosolve acetate. Of these, N-methylpyrrolidone, γ-butyrolactone, and N, N-dimethylacetamide are preferable.

  The composition solution prepared in this way can be used for use after filtration through a Millipore filter having a pore size of, for example, about 0.2 to 0.5 μm, if necessary.

In the photosensitive resin composition (A) of the present invention, the solid content concentration and the viscosity at 25 ° C. need to satisfy the relationships of the following formulas (1) to (4).
LogY ≦ 0.04X−0.08 (1)
LogY ≧ 0.04X−0.50 (2)
LogY ≧ 0.30 (3)
LogY ≦ 1.08 (4)
Where X is the solids concentration (% by weight) and Y is the viscosity of this composition at 25 ° C. (mPa · s).

When the LogY viscosity is less than 0.30, the coating film thickness is uneven at the edge of the substrate when coated with a slit die coater, and when the LogY viscosity is greater than 1.08, liquid breakage from the slit nozzle tends to occur. . The occurrence of liquid breakage is not preferable because it causes unevenness on the muscles.
Further, LogY> 0.04X-0.08 is not preferable because the solid concentration is not sufficient, and it takes a long time to dry the coating film, resulting in a decrease in productivity. When LogY <0.04X−0.50, the pattern shape tends to be reversely tapered, which is not preferable.

The photosensitive resin composition (A) is particularly suitable as a material for forming spacers for display panels such as liquid crystal panels and touch panels.
When forming a display panel spacer using the display panel spacer photosensitive resin composition (a), after applying the composition solution to the surface of the substrate, pre-baking to remove the solvent, the coating film Form.

As a coating method of the composition solution, for example, an appropriate method such as a spray method, a roll coating method, a spin coating method (spin coating method), a slit die coating method, a bar coating method, or an ink jet coating method can be employed. In particular, a spin coating method and a slit die coating method are preferable.
Moreover, although the conditions of prebaking differ also with the kind of each structural component, a mixture ratio, etc., it is normally about 1 to 15 minutes at 70-90 degreeC.

Next, the pre-baked coating film is exposed and polymerized through a mask having a predetermined pattern, and then developed with a developing solution, and unnecessary portions are removed to form a pattern.
As radiation used for exposure, visible light, ultraviolet light, far ultraviolet light, charged particle beam, X-ray and the like can be appropriately selected, but radiation having a wavelength in the range of 190 to 450 nm is preferable.
As the developing method, for example, any of a liquid filling method, a dipping method, a shower method and the like may be used, and the developing time is usually 30 to 180 seconds.

Examples of the developer include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and ammonia; primary amines such as ethylamine and n-propylamine; Secondary amines such as n-propylamine; tertiary amines such as trimethylamine, methyldiethylamine, ethyldimethylamine and triethylamine; tertiary alkanolamines such as dimethylethanolamine, methyldiethanolamine and triethanolamine; pyrrole and piperidine , N-methylpiperidine, N-methylpyrrolidine, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] -5-nonene 3 Secondary amines: pyridine, collidine, ru Jin, aromatic tertiary amines such as quinoline; tetramethylammonium hydroxide, the aqueous solution of an alkaline compound such as quaternary ammonium salts such as tetraethyl ammonium hydroxide may be used.
In addition, an appropriate amount of a water-soluble organic solvent such as methanol or ethanol and / or a surfactant can be added to the aqueous solution of the alkaline compound.

After development, for example, by washing with running water, for example, for 30 to 90 seconds, unnecessary portions are removed, and then compressed air or compressed nitrogen is blown to dry to form a predetermined pattern.
Thereafter, the pattern is heated by a heating device such as a hot plate or an oven at a predetermined temperature, for example, 150 to 250 ° C., for a predetermined time, for example, for 5 to 30 minutes on the hot plate, or for 30 to 90 minutes in the oven. By doing so, the target spacer can be obtained.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples.
Synthesis example 1
A flask equipped with a condenser and a stirrer was charged with 5 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 224 parts by weight of diethylene glycol methyl ethyl ether, followed by 15 parts by weight of methacrylic acid and methacrylic acid. After charging 30 parts by weight of glycidyl, 8 parts by weight of styrene, and 44 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, and substituting with nitrogen, 5 weights of 1,3-butadiene is further added. The temperature of the solution was raised to 70 ° C. while gently stirring, and the temperature was maintained for 4 hours for polymerization to obtain a solution of copolymer [A-1].
The solid content concentration of this solution was 29.1% by weight, and the Mw of the copolymer [A-1] was 10,000.

Synthesis example 2
A flask equipped with a condenser and a stirrer was charged with 7 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 255 parts by weight of diethylene glycol methyl ethyl ether, followed by 15 parts by weight of methacrylic acid and methacrylic acid. After charging 30 parts by weight of glycidyl, 8 parts by weight of styrene, 47 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, and substituting with nitrogen, 5 weights of 1,3-butadiene is further added. The temperature of the solution was raised to 70 ° C. while stirring gently, and this temperature was maintained for 4 hours for polymerization to obtain a solution of copolymer [A-2].
The solid content concentration of this solution was 29.0% by weight, and the Mw of the copolymer [A-2] was 5,000.

Synthesis example 3
A flask equipped with a condenser and a stirrer was charged with 2 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 150 parts by weight of diethylene glycol methyl ethyl ether, followed by 15 parts by weight of methacrylic acid and methacrylic acid. After charging 30 parts by weight of glycidyl, 8 parts by weight of styrene, and 44 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, and purging with nitrogen, The temperature was raised to 70 ° C., and this temperature was maintained for 7 hours for polymerization to obtain a solution of copolymer [A-3].
The solid content concentration of this solution was 37.8% by weight, and the Mw of the copolymer [A-3] was 50,000.

Synthesis example 4
A flask equipped with a condenser and a stirrer was charged with 3.5 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 180 parts by weight of diethylene glycol methyl ethyl ether, followed by 15 parts by weight of methacrylic acid, While charging 30 parts by weight of glycidyl methacrylate, 8 parts by weight of styrene, and 44 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, and substituting with nitrogen, The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 5 hours for polymerization to obtain a solution of copolymer [A-4].
The solid content concentration of this solution was 34.0% by weight, and the Mw of the copolymer [A-4] was 30,000.

Synthesis example 5
A flask equipped with a condenser and a stirrer was charged with 5 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) and 224 parts by weight of diethylene glycol methyl ethyl ether, followed by 15 parts by weight of methacrylic acid and methacrylic acid. After charging 30 parts by weight of glycidyl, 8 parts by weight of styrene, and 44 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate, and purging with nitrogen, The temperature was raised to 70 ° C., and this temperature was maintained for 4 hours for polymerization to obtain a solution of copolymer [A-5].
The solid content concentration of this solution was 29.7% by weight, and the Mw of the copolymer [A-5] was 10,000.

Example 1
Preparation of Composition Solution 100 parts by weight (solid content) of the copolymer [A-1] obtained in Synthesis Example 1 as a copolymer [A], and KAYARAD DPHA (Nippon Kayaku) as a polymerizable compound [B] Co., Ltd.) 100 parts by weight, 2-benzyl-2-N, N-dimethylamino-1- (4-morpholinophenyl) -1-butanone (trade name “IRGACURE 369”, Ciba as photopolymerization initiator [C] (Specialty Chemicals) 15 parts by weight is mixed, dissolved in diethylene glycol methyl ethyl ether as a solvent so that the solid content concentration is 25.5% by weight, and then filtered through a PTFE filter with a pore size of 0.2 μm. A composition solution (S-1) was prepared.
(I) Evaluation of vacuum drying (VCD) time After curing the prepared composition solution on a 550 × 650 mm chromium-deposited glass using a slit die coater (TR632105-CL, manufactured by Tokyo Ohka Kogyo Co., Ltd.) The film thickness was 4 μm and 1.5 μm. Thereafter, the time until the degree of reduced pressure reached 0.5 Torr from normal pressure was measured. A shorter VCD time is advantageous.
(II) Evaluation of applicability (substrate lift pin mark) The prepared composition solution was applied onto a 550 × 650 mm chromium-deposited glass using a slit die coater. After drying under reduced pressure to 0.5 Torr, pre-baking on a hot plate at 100 ° C. for 2 minutes to form a coating film, and further exposing at an exposure amount of 2000 J / m ² , Films with film thicknesses of 4 μm and 1.5 μm were formed.

The surface of the film was illuminated with a sodium lamp, and the coated film surface was visually confirmed. When the substrate lifting pin trace was clearly confirmed, it was evaluated as “X”, when it was confirmed slightly, “△” when almost not confirmed, and “◎” when no substrate lifting pin trace was confirmed.
(III) Evaluation of applicability (uniformity) The film thickness of the coating film on the chromium film-forming glass produced as described above was measured using a needle contact type measuring instrument (AS200 manufactured by KLA Tencor).
The uniformity was calculated from the film thickness at nine measurement points. The nine measurement points are X (mm) and Y (mm) when the short axis direction of the substrate is X and the long axis direction is Y (275, 20), (275, 30), (275, 60), (275, 100), (275, 325), (275, 550), (275, 590), (275, 620), (275, 630).
The uniformity calculation formula is expressed by the following formula (3). In the following formula (3), FT (X, Y) max is the maximum value in the film thickness at nine measurement points, FT (X, Y) min is the minimum value in the film thickness at nine measurement points, and FT (X, Y Y) avg is an average value in the film thickness at nine measurement points. When the uniformity is less than 2%, ◎, when 2-3%, ◯, when 3-5%, △, when 5% or more, ×.
Uniformity (%) = {FT (X, Y) max−FT (X, Y) min} × 100 / {2 × FT (X, Y) avg} (3)

(IV) Evaluation of pattern shape After applying the composition solution on a non-alkali glass substrate using a spinner, pre-baking on a hot plate at 90 ° C. for 3 minutes to form a coating film having a thickness of 1.5 μm did.
Subsequently, the obtained film was irradiated with ultraviolet rays for 10 seconds at an intensity of 365 W / m ² at 365 nm through a mask having a 10 μm square pattern. Thereafter, development was performed with a 0.05 wt% potassium hydroxide aqueous solution at 25 ° C. for 60 seconds, and then rinsed with pure water for 1 minute. Furthermore, it heated at 150 degreeC for 120 minute (s) in oven, and the spacer was formed.
The results of observing the cross-sectional shape of the obtained spacer pattern with a scanning electron microscope are shown in Table 1 depending on which shape of A to C shown in FIG. When the pattern edge is formed in a forward taper or vertical shape as in A or B, the pattern shape can be said to be good. As shown in C, the shape that becomes a reverse taper (in which the side of the film surface in the cross-sectional shape is longer than the side on the substrate side, an inverted triangular shape) is very likely to peel off the pattern during the subsequent rubbing process. Therefore, such a shape was regarded as defective.

(V) Viscosity measurement It measured at 25 degreeC with the E-type viscosity meter (Toki Sangyo Co., Ltd. VISCONIC ELD.R).
(VI) Measurement of Solid Concentration About 0.3 g of the composition solution is prepared on an aluminum dish, about 1 g of diethylene glycol dimethyl ether is added, and then dried on a hot plate at 175 ° C. for 60 minutes. The solid content concentration was determined.

Examples 2-11, Comparative Examples 1-5
In Example 1, a composition solution was prepared in the same manner as in Example 1 except that the types and amounts described in Table 1 were used as [A] component to [C] component. Formed and evaluated. The addition amount of [B]-[C] is a weight ratio with respect to 100 parts by weight of the copolymer [A].

In Table 1, the abbreviations of the components indicate the following compounds.
(B-1): Dipentaerystol hexaacrylate (KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.)
(B-2): KAYARAD DPHA-40H (manufactured by Nippon Kayaku Co., Ltd.)
(Nippon Kayaku Co., Ltd.)
(C-1): 2-benzyl-2-N, N-dimethylamino-1- (4-morpholinophenyl) -1-butanone (IRGACURE 369, manufactured by Ciba Specialty Chemicals)
(C-2): 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (IRGACURE 907 manufactured by Ciba Specialty Chemicals)
(C-3): 2,2′-bis (2,4-dichlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole (C-4): 4,4 ′ -Bis (diethylamino) benzophenone (C-5): 2-mercaptobenzothiazole In Table 1,-mark shows that this component is not added.

Schematic cross-sectional shape of spacer pattern

Explanation of symbols

A: Pattern edge has a forward tapered shape B ... Pattern edge has a vertical shape C ... Pattern edge has a reverse tapered shape

Claims (3)

[A] (a1) at least one selected from the group consisting of ethylenically unsaturated carboxylic acids and ethylenically unsaturated carboxylic acid anhydrides, (a2) an epoxy group-containing ethylenically unsaturated compound, and (a3) (a1) And a copolymer with another ethylenically unsaturated compound different from (a2),
[B] A polymerizable compound having an ethylenically unsaturated bond and [C] a photopolymerization initiator, and having a solid content concentration and a viscosity at 25 ° C. of the following formulas (1) to (4):
LogY ≦ 0.04X−0.08 (1)
LogY ≧ 0.04X−0.50 (2)
LogY ≧ 0.30 (3)
LogY ≦ 1.08 (4)
Where X is the solids concentration (wt%) and Y is the viscosity (mPa · s) at 25 ° C.
Satisfy the relationship
The photosensitive resin composition characterized by the above-mentioned. A display panel spacer formed from the photosensitive resin composition according to claim 1. A display panel comprising the display panel spacer according to claim 2.

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