JP2008151967A - Radiation-sensitive resin composition, spacer and method for producing the spacer and liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition capable of faithfully reproducing the design size of a mask pattern with high sensitivity, excellent in adhesion to a substrate, capable of obtaining a satisfactory spacer shape and film thickness under an exposure energy of ≤1,500 J/m<SP>2</SP>, excellent also in strength and heat resistance, and excellent in controllability of spacer shape and film thickness in a low exposure energy region. <P>SOLUTION: The radiation-sensitive resin composition comprises (A) a copolymer of an unsaturated carboxylic acid and/or an unsaturated carboxylic acid anhydride, a (meth)acrylate having a steroid skeleton, such as lithocholic acid (meth)acrylate, and an unsaturated compound different from these, (B) a polymerizable unsaturated compound and (C) a radiation-sensitive polymerization initiator. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radiation-sensitive resin composition, a spacer, a production method thereof, and a liquid crystal display element. More specifically, a radiation-sensitive resin composition suitable as a material for forming a spacer used in a display element such as a liquid crystal display panel or a touch panel, a display element spacer formed from the composition, and the spacer The present invention relates to a liquid crystal display element.

Conventionally, spacer particles such as glass beads and plastic beads having a predetermined particle diameter have been used for liquid crystal display elements in order to keep the distance (cell gap) between two substrates constant. Since particles are randomly distributed on a transparent substrate such as a glass substrate, the presence of spacer particles in the pixel formation region may cause a phenomenon of spacer particle reflection or scattering of incident light, resulting in a contrast of the liquid crystal panel. 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 radiation-sensitive resin composition is applied onto a substrate, exposed to ultraviolet rays through a predetermined mask, and then developed to form dot-shaped or stripe-shaped spacers. Since the spacer can be formed only at a predetermined position, the above-described problem is basically solved.

In recent years, from the viewpoint of manufacturing cost, the number of cases where it is used in the same process as a conventionally used material has increased. In such cases, the radiation-sensitive resin composition for interlayer insulation films and the radiation-sensitive resin composition for spacers are often used under conditions that deviate from the optimum process conditions, especially when the pre-bake temperature deviates from the optimum conditions. There is a problem that a high resolution cannot be obtained or the pattern is peeled off. Further, as the substrate becomes larger, the warpage of the substrate during proximity baking becomes more prominent, and the temperature distribution occurs even on the same substrate, so that the radiation-sensitive resin composition for an interlayer insulating film having a wider process margin, There is also a need for a radiation sensitive resin composition for spacers.
Therefore, in order to solve such a problem, the present applicant has already disclosed, in Patent Document 1, a sufficient process margin that can cope with changes in process conditions, and heat resistance necessary as an interlayer insulating film and spacer, A radiation-sensitive resin composition capable of giving a cured product having both chemical resistance, transparency and hardness has been clarified.

Furthermore, in recent years, from the viewpoint of improving productivity, a process technology “ODF (One Drop Fill) method” in which a liquid crystal material is brought to the glass surface before the glass of the liquid crystal panel is bonded is introduced.
This approach can save a lot of time. For example, in the conventional method, it takes about 5 days to fill the liquid crystal for a 30-inch panel. However, if the ODF method is introduced, only 2 hours are required, and the productivity can be greatly improved.

In the conventional bonding method, since a load is applied when the TFT array and the color filter are bonded together, the spacer is pressed evenly by the load, and the height uniformity of the spacer is maintained. However, in the ODF method, the initial bonding load is smaller than the conventional method because the bonding is performed only by the load due to the weight of the substrate and the atmospheric pressure. Therefore, even if the spacer is pushed with a small load, it is important to develop height uniformity by being pushed evenly. For this purpose, the flexibility of the spacer is required. If the height of the spacer is not uniform, the cell gap cannot be kept uniform, causing a gap in the cell and causing display unevenness.
However, a conventional flexible spacer shows a high elastic deformation amount in a compression load test, but its elastic recovery rate tends to be low.
In order to solve this problem, Patent Document 2 proposes a radiation-sensitive resin composition containing a resin containing an alicyclic compound having a polycyclic steric structure. However, in this case, since the resin has a polycyclic steric structure, the developability of the coating film of the composition with respect to an alkaline developer is significantly reduced.
JP 2001-302712 A JP 2002-174812 A

Therefore, the object of the present invention is to make it possible to form a sufficient spacer with an exposure amount of 1,500 J / m ² or less, excellent adhesion, rubbing resistance, heat resistance, and further flexibility and high elastic recovery rate, An object of the present invention is to provide a radiation-sensitive resin composition capable of forming a display element spacer having excellent developability with respect to an alkaline developer.

  Another object of the present invention is to provide a spacer formed from the above radiation sensitive resin composition, a method for producing the same, and a liquid crystal display device comprising the spacer.

  Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the objects and advantages are as follows:
[A] (a1) unsaturated carboxylic acid and / or unsaturated carboxylic acid anhydride,
(A2) an unsaturated compound represented by the following formula (1) or (2),

Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a carboxy group or an isopropyl group, and R ³ is a single bond or a linear or branched alkyl group having 1 to 8 carbon atoms. .)
(A3) Copolymers of unsaturated compounds other than the above (a1) and (a2), preferably,
[B] A radiation-sensitive resin composition containing a polymerizable unsaturated compound and [C] a radiation-sensitive polymerization initiator (hereinafter referred to as “radiation-sensitive resin composition (I)”). Achieved by:

According to the present invention, the objects and advantages are secondly:
This is achieved by a spacer for a liquid crystal display element formed from the radiation-sensitive resin composition (a) and a liquid crystal display element having the same.

According to the present invention, the object and advantages are thirdly:
This is achieved by a method for forming a spacer for a liquid crystal display element, comprising at least the following steps in the order described below.
(A) forming a film of the radiation sensitive resin composition described above on a substrate;
(B) exposing at least a part of the coating;
(C) a step of developing the coated film after exposure, and (d) a step of heating the coated film after development.

The radiation-sensitive resin composition (a) of the present invention is highly sensitive and can faithfully reproduce the design size of the mask pattern, has excellent adhesion to the substrate, and an exposure amount of 1,500 J / m ² or less is sufficient. The spacer shape and film thickness can be obtained, and the strength and heat resistance are excellent, and the spacer shape and film thickness controllability in the low exposure area are excellent.

  Hereinafter, the present invention will be described in detail.

Radiation sensitive resin composition (I)
-Copolymer [A]-
Copolymer [A] can be produced by radical polymerization of compound (a1), compound (a2) and compound (a3) in the presence of a polymerization initiator in a solvent.
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; and 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. 2-methacryloyloxyethyl hexahydrophthalic acid and the like are preferable.

In the radiation sensitive resin composition (A), the unsaturated carboxylic acid monomer (a1) can be used alone or in admixture 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. If 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 if it exceeds 50% by weight, the alkaline aqueous solution There is a possibility that the solubility in is too large.

Among the components constituting the copolymer [A], the component (a2) is represented by the above formula (1) or (2). In the formula, R ¹ is a hydrogen atom or a methyl group, R ² is a carboxy group or an isopropyl group, and R ³ is a single bond or a linear or branched alkyl group having 1 to 8 carbon atoms. As a specific example of the above formula (1), when R ¹ is a hydrogen atom, R ² is a carboxy group, and R ³ is a single bond, lithocholic acid acrylate, R ¹ is a methyl group, R ² is a carboxy group, and R ³ is In the case of a single bond, lithocholic acid methacrylate, R ¹ is a hydrogen atom, R ² is an isopropyl group, and R ³ is a single bond, cholestanol acrylate,
When R ¹ is a methyl group, R ² is an isopropyl group, and R ³ is a single bond, cholestanol methacrylate is exemplified.
Among these, lithocholic acid acrylate, lithocholic acid methacrylate, cholestanol methacrylate from the point of showing the excellent developability of the radiation sensitive resin composition to the alkaline developer, the flexibility of the obtained spacer and a high elastic recovery rate Preferably used. The component (a2) is used alone or in combination.

  The copolymer [A] used in the present invention preferably contains 1 to 70% by weight, particularly preferably 3 to 50% by weight, of structural units derived from the compound (a2). When this structural unit is less than 3% by weight, the elastic recovery rate of the obtained spacer tends to decrease, while when it exceeds 70% by weight, the heat resistance tends to decrease.

Further, (a3) other ethylenically unsaturated compounds (hereinafter simply referred to as “other monomers”) include, for example, alkyl acrylates such as methyl acrylate and i-propyl acrylate; methacrylic acid Methacrylic acid alkyl esters such as methyl, ethyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate; cyclohexyl acrylate, 2-methylcyclohexyl acrylate, tricycloacrylate [5.2.1 0.0 ^2,6 ] decan-8-yl, acrylic acid alicyclic esters such as 2- (tricyclo [5.2.1.0 ^2,6 ] decan-8-yloxy) ethyl, isobornyl acrylate; Cyclohexyl methacrylate, 2-methylcyclohexyl methacrylate, tricyclomethacrylate [5. .1.0 ^2,6] decan-8-yl, 2-methacrylate (tricyclo [5.2.1.0 ^2,6] decan-8-yloxy) ethyl, methacryl San'abura cyclic methacrylic acid isobornyl Esters; aryl esters or aralkyl esters of acrylic acid such as phenyl acrylate and benzyl acrylate; aryl esters or aralkyl esters of methacrylic acid such as phenyl methacrylate and benzyl methacrylate; diethyl maleate, diethyl fumarate, diethyl itaconate, etc. Dicarboxylic acid dialkyl ester of methacrylic acid hydroxyalkyl ester such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2- (6-hydroxyethylhexanoyloxy) ethyl methacrylate; Unsaturated hetero 5- and 6-membered methacrylic acid esters containing one atom of oxygen such as trahydrofurfuryl, tetrahydrofuryl methacrylate, tetrahydrofupyran-2-methyl methacrylate; glycidyl acrylate, 2-methylglycidyl acrylate, acrylic Acrylic acid epoxy alkyl esters such as 3,4-epoxybutyl acid, 6,7-epoxyheptyl acrylate, 3,4-epoxycyclohexyl acrylate; glycidyl methacrylate, 2-methylglycidyl methacrylate, 3,4-methacrylic acid 3,4- Epoxy butyl, methacrylic acid epoxy alkyl esters such as methacrylic acid 6,7-epoxyheptyl, 3,4-epoxycyclohexyl methacrylate; α-ethyl acrylate glycidyl, α-n-propyl acrylate glycidyl, α-n-butyl Α-alkylacrylic acid epoxy alkyl esters such as glycidyl crylate and α-ethyl acrylate 6,7-epoxyheptyl; glycidyl ethers such as o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether Vinyl aromatic compounds such as styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene; phenylmaleimide, cyclohexylmaleimide, benzylmaleimide, N-succinimidyl-3-maleimidobenzoate, N-succinimidyl -4-maleimidobutyrate, N-succinimidyl-6-maleimidocaproate, N-succinimidyl-3-maleimidopropionate, N- (9-acridinyl) maleimide, etc. In addition to conjugated diene compounds such as 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl chloride, vinylidene chloride And vinyl acetate.

Among these other monomers, from the viewpoint of copolymerization reactivity and solubility of the resulting copolymer in an alkaline aqueous solution, 2-methylcyclohexyl acrylate, 2-hydroxyethyl methacrylate, styrene, glycidyl methacrylate, Preferred are tetrahydrofurfuryl methacrylate and 1,3-butadiene methacrylate 2- (6-hydroxyethylhexanoyloxy) ethyl ester.
In the copolymer [A], other monomers can be used alone or in admixture of two or more.

The copolymer [A] used in the present invention preferably contains 10 to 70% by weight, more preferably 20 to 50% by weight, and particularly preferably 30 to 50% by weight of the structural unit derived from the compound (a3). Contains. When the structural unit is less than 10% by weight, the storage stability of the copolymer [A] tends to be reduced. On the other hand, when it exceeds 70% by weight, the copolymer [A] is hardly dissolved in the alkaline aqueous solution. .
As described above, the copolymer [A] used in the present invention has a carboxyl group and / or a carboxylic anhydride group and an unsaturated compound represented by the chemical formula (1) or (2), It has appropriate solubility in an aqueous solution and can be easily cured by heating without using a special curing agent.
The radiation-sensitive resin composition containing the copolymer [A] exhibits good alkali solubility during development, and can easily form a spacer having a predetermined pattern.
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, and the like;
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, 3-methoxybutyl acetate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate Propyl 2-methoxypropionate, 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, 3-methoxypropionic acid Lopyl, butyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, propyl 3-ethoxypropionate, butyl 3-ethoxypropionate, methyl 3-propoxypropionate, ethyl 3-propoxypropionate , Esters of propyl 3-propoxypropionate, butyl 3-propoxypropionate, methyl 3-butoxypropionate, ethyl 3-butoxypropionate, propyl 3-butoxypropionate, butyl 3-butoxypropionate, etc. it can.

  Of these, ethylene glycol alkyl ether acetate, diethylene glycol, dipropylene glycol, propylene glycol monoalkyl ether, and propylene glycol alkyl ether acetate are preferred. 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, propylene glycol methyl ether acetate, and 3-methoxybutyl 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 examples thereof include 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 pionate) and 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile); benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, 1,1-bis (t-butyl) Peroxy) organic peroxides such as 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. If the Mw is less than 2,000, the developability and the remaining film ratio of the resulting film may be reduced, and the pattern shape, heat resistance, etc. may be impaired. There exists a possibility that it may fall or a pattern shape may be impaired.

-Polymerizable compound [B]-
The component [B] in the radiation-sensitive 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 thereof include methoxybutyl acrylate, 3-methoxybutyl methacrylate, 2-acryloyloxyethyl-2-hydroxypropyl phthalate, and 2-methacryloyloxyethyl-2-hydroxypropyl phthalate. Commercial products include, 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.) VISCOAT 158, mention may be made of the same 2311 (manufactured by Osaka Organic Chemical Industry Co., Ltd.) and the like.

  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- Hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol diacrylate, 1,9-nonanediol dimethacrylate, bisphenoxyethanol full orange acrylate, bisphenoxyethanol full orange methacrylate, etc. As commercial products, for example, Aronix M-210, M-240, M-6200 (manufactured by Toa Gosei Co., Ltd.) KAYARAD HDDA, the HX-220, the R-604 (manufactured by Nippon Kayaku Co.), Viscoat 260, the 312, can be exemplified by the same 335HP (manufactured by Osaka Organic Chemical Industry Ltd.) and the like.

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, a (meth) acrylate having 9 or more functional groups has an alkylene straight chain and an alicyclic structure, a compound containing two or more isocyanate groups, and a trifunctional, tetrafunctional and 5 functional group containing one or more hydroxyl groups in the molecule. The urethane acrylate compound obtained by making a functional (meth) acrylate compound react is mentioned.
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. Commercially available products of polyfunctional urethane acrylates having 9 or more functional groups include, for example, New Frontier R-1150 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), KAYARAD DPHA-40H (manufactured by Nippon Kayaku Co., Ltd.), etc. 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 radiation sensitive resin composition (A), the amount of the polymerizable compound [B] used is preferably 50 to 200 parts by weight, more preferably 60 to 150 parts by weight, based on 100 parts by weight of the copolymer [A]. Part. If the amount of the polymerizable compound [B] used is less than 50 parts by weight, there may be a residual image during development, whereas if it exceeds 200 parts by weight, the adhesion of the resulting spacer tends to be reduced.

-Radiation sensitive polymerization initiator [C]-
The radiation-sensitive polymerization initiator in the radiation-sensitive resin composition is an active species that can initiate polymerization of a polymerizable unsaturated compound by exposure to radiation such as visible light, ultraviolet light, far ultraviolet light, charged particle beam, and X-ray. Consists of components that occur. As such a radiation sensitive polymerization initiator, for example, 9. H. A carbazole-based O-acyloxime polymerization initiator (hereinafter referred to as “O-acyloxime polymerization initiator (I)”) is preferable.

  Examples of the O-acyloxime polymerization initiator (I) 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. -Carbazol-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- (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-1-one oxime-O-benzoate, ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9. H. -Carbazol-3-yl]-, 1- (O-acetyloxime), ethanone, 1- [9-ethyl-6- [2-methyl-4- (2,2-dimethyl-1,3-dioxolanyl) methoxy Benzoyl] -9. H. -Carbazol-3-yl]-, 1- (O-acetyloxime), ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9. H. -Carbazol-3-yl]-, 1- (O-acetyloxime) and the like.

Of these O-acyloxime type polymerization initiators (I), in particular, ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9. H. -Carbazol-3-yl]-, 1- (O-acetyloxime), ethanone, 1- [9-ethyl-6- [2-methyl-4- (2,2-dimethyl-1,3-dioxolanyl) methoxy Benzoyl] -9. H. -Carbazol-3-yl]-, 1- (O-acetyloxime) is preferred.
The O-acyloxime type polymerization initiator (I) can be used alone or in admixture of two or more.
In the present invention, by using an O-acyloxime type carbazole compound (C1) or another O-acyloxime type photopolymerization initiator as a polymerization initiator [C] component, 1,500 J / m ^{Even with} an exposure amount of ² or less, a display panel spacer having high sensitivity and excellent adhesion to a substrate can be formed.

  In the radiation sensitive resin composition (I), the total amount of the O-acyloxime carbazole compound (C1) and the other O-acyloxime photopolymerization initiator used is 100 parts by weight of the polymerizable compound [B]. On the other hand, it is preferably 1 to 30 parts by weight, more preferably 2 to 20 parts by weight. When the amount of the photopolymerization initiator [C] used is less than 1 part by weight, the residual film ratio tends to be reduced during development. Tends to decrease.

Furthermore, as other polymerization initiators other than other O-acyloxime photopolymerization initiators, for example, biimidazole compounds, benzoin compounds, acetophenone compounds, benzophenone compounds, α-diketone compounds, radiation sensitive compounds, and the like. Examples of the cationic polymerization initiator include onium salts and metallocene compounds. Of these, acetophenone compounds, biimidazole compounds, and radiation-sensitive cationic polymerization initiators are preferred.
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: Examples include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1-one, and the like. be able to.
These acetophenone compounds can be used alone or in admixture of two or more.
In the present invention, by using an acetophenone-based compound as another polymerization initiator, it is possible to further improve the sensitivity, the shape of the obtained spacer, the compressive strength, and the like.

Specific examples of the biimidazole compound include, for example,
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.

In addition, when a biimidazole compound is used as another polymerization initiator, an aromatic compound having a dialkylamino group (hereinafter referred to as “dialkylamino group-containing sensitizer”) is used in combination to sensitize it. Can do.
Examples of the dialkylamino group-containing sensitizer include 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone, ethyl p-dimethylaminobenzoate, ethyl p-diethylaminobenzoate, Examples include i-amyl p-dimethylaminobenzoate and i-amyl p-diethylaminobenzoate.
Of these dialkylamino group-containing sensitizers, 4,4′-bis (diethylamino) benzophenone is preferred.
The dialkylamino group-containing sensitizer can be used alone or in admixture of two or more.
The amount of the dialkylamino group-containing 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 the copolymer [A]. If the amount of the dialkylamino group-containing sensitizer used is less than 0.1 parts by weight, the resulting spacer may be slipped or the pattern shape may be impaired. The pattern shape of the spacer may be damaged.

  Furthermore, when a biimidazole compound and a dialkylamino group-containing sensitizer are used in combination as other polymerization initiators, a thiol compound can be added as a hydrogen donor compound. A biimidazole compound is sensitized and cleaved by a dialkylamino group-containing sensitizer to generate an imidazole radical, but at this time, high polymerization initiating ability is not necessarily expressed, and the obtained spacer has a reverse taper shape. In many cases, such an undesirable shape is obtained. This problem can be alleviated by adding a thiol compound to a system in which a biimidazole compound and a dialkylamino group-containing sensitizer coexist. In other words, hydrogen radicals are donated to the imidazole radical from the thiol compound, so that the imidazole radical becomes a neutral imidazole and a component having a sulfur radical having a high polymerization initiation ability is generated. It becomes a shape.

Examples of the thiol compound include aromatics such as 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-5-methoxybenzothiazole, 2-mercapto-5-methoxybenzimidazole. Aliphatic monothiols such as thiols, 3-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.
These thiol compounds can be used alone or in admixture of two or more.

  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 copolymer [A]. When the amount of the thiol compound used is less than 0.1 parts by weight, the resulting spacer tends to suffer from film slipping or pattern shape defects, whereas when it exceeds 50 parts by weight, the spacer pattern shape may be impaired. is there.

  Further, as the radiation-sensitive polymerization initiator, onium salts such as phenyldiazonium tetrafluoroborate, phenyldiazonium hexafluorophosphonate, phenyldiazonium hexafluoroarsenate, phenyldiazonium trifluoromethanesulfonate, phenyldiazonium trifluoroacetate, phenyldiazonium-p -Toluenesulfonate, 4-methoxyphenyldiazonium tetrafluoroborate, 4-methoxyphenyldiazonium hexafluorophosphonate, 4-methoxyphenyldiazonium hexafluoroarsenate, 4-methoxyphenyldiazonium trifluoromethanesulfonate, 4-methoxyphenyldiazonium trifluoro Acetate, 4-methoxyphenyldiazoni Mu-p-toluenesulfonate, 4-ter-butylphenyldiazonium tetrafluoroborate, 4-ter-butylphenyldiazonium hexafluorophosphonate, 4-ter-butylphenyldiazonium hexafluoroarsenate, 4-ter-butylphenyldiazonium trifluoro Diazonium salts such as romethanesulfonate, 4-ter-butylphenyldiazonium trifluoroacetate, 4-ter-butylphenyldiazonium-p-toluenesulfonate; triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluorophosphonate, triphenylsulfonium Hexafluoroarsenate, triphenylsulfonium trifluoromethanesulfonate, triphenyls Honium trifluoroacetate, triphenylsulfonium-p-toluenesulfonate, 4-methoxyphenyldiphenylsulfonium tetrafluoroborate, 4-methoxyphenyldiphenylsulfonium hexafluorophosphonate, 4-methoxyphenyldiphenylsulfonium hexafluoroarsenate, 4-methoxy Phenyldiphenylsulfonium trifluoromethanesulfonate, 4-methoxyphenyldiphenylsulfonium trifluoroacetate, 4-methoxyphenyldiphenylsulfonium-p-toluenesulfonate, 4-phenylthiophenyldiphenyltetrafluoroborate, 4-phenylthiophenyldiphenylhexafluorophosphonate 4-phenylthiophenyldiphenylhexafluo Examples include sulfonium salts such as loarsenate, 4-phenylthiophenyldiphenyltrifluoromethanesulfonate, 4-phenylthiophenyldiphenyltrifluoroacetate, 4-phenylthiophenyldiphenyl-p-toluenesulfonate.

Examples of the metallocene compound include (1-6-η-cumene) (η-cyclopentadienyl) iron (1+) hexafluorophosphate (1-).
Commercially available products of these radiation-sensitive polymerization initiators include, for example, ADEKA ULTRASET PP-33 (made by ADEKA), which is a diazonium salt, OPTOMER SP-150, which is a sulfonium salt, and -170 (made by ADEKA). ), And Irgacure 261 (manufactured by Ciba Specialty Chemicals), which is a metallocene compound.
Said polymerization initiator can be used individually or in mixture of 2 or more types.

  In the radiation sensitive resin composition (I), the use ratio of the other polymerization initiator is preferably 100 parts by weight or less, more preferably 80 parts by weight or less, with respect to 100 parts by weight of the total radiation sensitive polymerization initiator. The amount is particularly preferably 60 parts by weight or less. In this case, if the use ratio of the other photopolymerization initiator exceeds 100 parts by weight, the intended effect of the present invention may be impaired.

-Additives-
In the radiation sensitive resin composition (A), additives other than the above-described components can be blended as necessary within a 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 diester. (1,1,2,2-tetrafluorobutyl) ether, hexaethylene glycol (1,1,2,2,3,3-hexafluoropentyl) ether, octapropylene glycol di (1,1,2,2- Tetrafluorobutyl) ether, hexapropylene glycol di (1,1,2,2,3,3-hexafluoropentyl) ether, sodium perfluorododecylsulfonate, 1,1,2,2,8,8,9, 9,10,10-decafluorododecane, 1,1,2,2,3,3-hexafluorodecane, sodium fluoroalkylbenzenesulfonate Sodium fluoroalkylphosphonate, sodium fluoroalkylcarboxylate, fluoroalkylpolyoxyethylene ether, diglycerin tetrakis (fluoroalkylpolyoxyethylene ether), fluoroalkylammonium iodide, fluoroalkylbetaine, fluoroalkylpolyoxyethylene ether, Examples thereof include 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 the surfactant other than the above include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether; polyoxyethylene n-octylphenyl ether, polyoxyethylene Polyoxyethylene aryl ethers such as 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 ( Product), 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]. When the compounding amount of the surfactant exceeds 5 parts by weight, there is a tendency that film roughening tends to occur during coating.
Moreover, in order to further improve the adhesion to the substrate, an adhesion assistant can be blended.

As the adhesion assistant, 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]. When the blending amount of the adhesion assistant exceeds 20 parts by weight, there is a tendency that a development residue tends 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) glycol. Uril, N, N, N ′, N′-tetra (n-propoxymethyl) glycoluril, N, N, N ′, N′-tetra (i-propoxymethyl) glycoluril, N, N, N ′, N Examples include '-tetra (n-butoxymethyl) glycoluril, 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 can be mentioned. 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.

The composition solution radiation-sensitive resin composition (a) is generally suitable for use with components such as a copolymer [A], a polymerizable compound [B], and a radiation-sensitive polymerization initiator [C]. It is prepared as a composition solution by dissolving the solvent.
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, ethyl ethoxypropionate, and -3-methoxybutyl acetate 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.
The radiation sensitive resin composition (A) is particularly suitable as a material for forming spacers for display elements such as liquid crystal panels and touch panels.

When forming a display element spacer using the display element spacer radiation-sensitive resin composition (a), the composition solution is applied to the surface of the substrate and then pre-baked to remove the solvent. A film is formed.
As a method of forming a film of the radiation sensitive resin composition of the present invention, for example, (1) a coating method and (2) a dry film method can be used.
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.
Further, when the film of the radiation-sensitive resin composition of the present invention is formed, (2) when the dry film method is adopted, the dry film is formed on a base film, preferably a flexible base film. It is one obtained by laminating a photosensitive layer comprising the radiation-sensitive resin composition of the invention (hereinafter referred to as “photosensitive dry film”).

  The photosensitive dry film can be formed by laminating a photosensitive layer by applying the radiation-sensitive resin composition of the present invention on a base film, preferably as a liquid composition, and then drying. As a base film of the photosensitive dry film, for example, a synthetic resin film such as polyethylene terephthalate (PET), polyethylene, polypropylene, polycarbonate, polyvinyl chloride, or the like can be used. The thickness of the base film is suitably in the range of 15 to 125 μm. The thickness of the obtained photosensitive layer is preferably about 1 to 30 μm.

When the photosensitive dry film is not used, a cover film can be further laminated on the photosensitive layer for storage. This cover film needs to have an appropriate releasability so that it does not peel off when not in use and can be easily peeled off when in use. As a cover film satisfying such conditions, for example, a silicone-based release agent is applied or baked onto the surface of a synthetic resin film such as a PET film, a polypropylene film, a polyethylene film, a polyvinyl chloride film, or a polyurethane film. be able to. The thickness of the cover film is usually preferably about 5 to 30 μm.
These cover films can be laminated with a two-layer or three-layer cover film as required.
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 4 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile), 115 parts by weight of propylene glycol monomethyl ether acetate, and 115 parts by weight of 3-methoxybutyl acetate. . Subsequently, 2 parts by weight of styrene, 7.5 parts by weight of methacrylic acid, 18 parts by weight of lithocholic acid methacrylate, 26 parts by weight of 2-methylglycidyl methacrylate, 2- (6-hydroxyethylhexanoyloxy) ethyl methacrylate (trade name PLACEL) FM1D (manufactured by Daicel Chemical Industries, Ltd.) 19.5 parts by weight and 19 parts by weight of benzyl methacrylate were charged and purged with nitrogen, and then gently stirred, the temperature of the solution was raised to 70 ° C., and this temperature was increased to 4 A polymer solution containing the copolymer [A-1] was obtained by holding for a period of time, and the resulting polymer solution had a solid content concentration of 27.3 wt%, and the weight average molecular weight of the polymer was 34,000. (Weight average molecular weight is GPC (gel permeation chromatography) Shodex GPC-101 (Showa Denko KK) Polystyrene equivalent molecular weight measured by).

Synthesis example 2
A flask equipped with a condenser and a stirrer was charged with 4 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile), 115 parts by weight of propylene glycol monomethyl ether acetate, and 115 parts by weight of 3-methoxybutyl acetate. . Subsequently, 2 parts by weight of styrene, 7.5 parts by weight of methacrylic acid, 30 parts by weight of lithocholic acid methacrylate, 19.5 parts by weight of 2-hydroxyethyl methacrylate and 38 parts by weight of benzyl methacrylate were charged, and the mixture was purged with nitrogen. I started. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer [A-2]. The solid content concentration of the obtained polymer solution was 27.3 wt%, and the weight average molecular weight of the polymer was 25,000 (weight average molecular weight was GPC (gel permeation chromatography) Shodex GPC- 101 (Molecular weight in terms of polystyrene measured using Showa Denko KK).

Synthesis example 3
A flask equipped with a condenser and a stirrer was charged with 4 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile), 115 parts by weight of propylene glycol monomethyl ether acetate, and 115 parts by weight of 3-methoxybutyl acetate. . Subsequently, 2 parts by weight of styrene, 10 parts by weight of methacrylic acid, 18 parts by weight of cholestanol methacrylate, 26 parts by weight of 2-methylglycidyl methacrylate, 22 parts by weight of 2-hydroxyethyl methacrylate, and 14 parts by weight of benzyl methacrylate were charged and nitrogen-substituted. After that, gentle stirring was started. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 4 hours to obtain a polymer solution containing the copolymer [A-3]. The solid content concentration of the obtained polymer solution was 27.3 wt%, and the weight average molecular weight of the polymer was 30,000 (weight average molecular weight was GPC (gel permeation chromatography) Shodex GPC- 101 (Molecular weight in terms of polystyrene measured using Showa Denko KK).

Comparative Synthesis Example 1
A flask equipped with a condenser and a stirrer was charged with 7 parts by weight of 2,2′-azobisisobutyronitrile and 200 parts by weight of propylene glycol monomethyl ether acetate. Subsequently, 12 parts by weight of methacrylic acid, 35 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decan-8-yl methacrylate (tricyclodecanyl methacrylate) and 45 parts by weight of methyl methacrylate were charged and the atmosphere was replaced with nitrogen. After that, gentle stirring was started. The temperature of the solution was raised to 70 ° C., and this temperature was maintained for 5 hours to obtain a polymer solution containing the copolymer [A-4]. The solid content concentration of the obtained polymer solution was 32.7% by weight, and the weight average molecular weight of the polymer was 30,000 (weight average molecular weight was GPC (gel permeation chromatography) Shodex GPC- 101 (Molecular weight in terms of polystyrene measured using Showa Denko KK).

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] 80 parts by weight, Etanone as photopolymerization initiator [C], 1- [9-ethyl-6- (2-methylbenzoyl) -9. H. -Carbazol-3-yl]-, 1- (O-acetyloxime) (Irgacure OX02 manufactured by Ciba Specialty Chemicals), 2-dimethylamino-2- (4-methyl-benzyl) -1- Propylene glycol monomethyl ether acetate with 10 parts by weight of (4-morpholin-4-yl-phenyl) -butan-1-one (Irgacure 379 manufactured by Ciba Specialty Chemicals Co., Ltd.) so that the solid content concentration is 30% by weight. Then, it was filtered through a Millipore filter having a pore size of 0.2 μm to prepare a composition solution (S-1).

(I) Formation of Spacer The above composition solution was applied onto an alkali-free glass substrate using a spinner, and then prebaked on a hot plate at 90 ° C. for 3 minutes to form a coating film having a thickness of 3.5 μm.
The coating film obtained above was exposed to ultraviolet rays having an exposure gap at a wavelength of 365 nm of 300 W / m ² with an exposure gap of 150 μm through a mask having a 15 μm square pattern. Next, development was performed with a 0.05 wt% aqueous solution of potassium hydroxide at 25 ° C. for 60 seconds, followed by a 1 minute rinse with pure water. Furthermore, it heated at 230 degreeC for 30 minute (s) in oven, and the spacer was formed.

(II) Evaluation of sensitivity When the spacer was formed in the same manner as the formation of the spacer (I) except that the exposure amount was changed, the residual film ratio after development (film thickness after development × 100 / initial film thickness) The same applies to the following). The following evaluation items were patterned by the sensitivity in each example. The evaluation results are shown in Table 2.

(III) Evaluation of developability When the development time is 40 seconds during development in (I) above, the pattern is formed (◯), the pattern is formed in 60 seconds (Δ), 60 The case where a residue was generated even for 2 seconds or more was evaluated as (x). The evaluation results are shown in Table 2.

(IV) Evaluation of rubbing resistance AL3046 (manufactured by JSR Co., Ltd.) as a liquid crystal aligning agent was applied to the substrate obtained in (I) above using a printing machine for applying a liquid crystal alignment film, and dried at 180 ° C. for 1 hour. A coating film of an orientation agent having a dry film thickness of 0.05 μm was formed.
The coating film was rubbed with a rubbing machine having a roll around which a nylon cloth was wound at a roll rotation speed of 500 rpm and a stage moving speed of 1 cm / sec. Table 2 shows the presence or absence of scraping or peeling of the spacer pattern.

(V) Evaluation of adhesiveness Except not using a pattern mask, it implemented similarly to said (I), formed the cured film for adhesiveness evaluation, and performed the adhesiveness test. The test method followed the cross-cut tape method of 8.5.2 in the adhesion test of JIS K-5400 (1900) 8.5. Table 2 shows the number of remaining grids (10 × 10). It can be said that the adhesiveness is good when all of the hundreds of grids remain.

(VI) Evaluation of heat-resistant dimensional stability The spacer pattern formed in the above (I) was further heated in an oven at 230 ° C. for 20 minutes, and then the change in the height of the spacer was measured. If the rate of change was less than 2%, it was evaluated as good (◯), if it was less than 2% to 4%, it was slightly good (Δ), and if it was 4% or more, it was evaluated as defective (x). The evaluation results are shown in Table 2.

(VII) Evaluation of elastic recovery rate About the obtained spacer, using a micro-compression tester (trade name DUH-201, manufactured by Shimadzu Corporation), a flat indenter with a diameter of 50 μm was used for both loading speed and unloading speed. A load of up to 50 mN was applied as 2.6 mN / sec, the load was held for 5 seconds, and then unloaded, and a load-deformation curve at loading and a load-deformation curve during unloading were created. At this time, as shown in FIG. 1, the difference between the deformation amount at the load of 50 mN and the deformation amount at the load of 5 mN is L1, and the deformation amount at the load of 50 mN and the deformation amount at the load of 5 mN at unloading. The elastic recovery rate was calculated by the following formula, with the difference between L2 and L2 (FIG. 1).
Elastic recovery rate (%) = L2 × 100 / L1
Table 2 shows the elastic recovery rate and the amount of mutation.

Examples 2-6 and Comparative Examples 1-2
In Example 1, a composition solution was prepared and a spacer was formed in the same manner as in Example 1, except that the types and amounts shown in Table 1 were used as the components [A] to [C]. And evaluated. The addition amount of [B]-[C] is a weight ratio with respect to 100 parts by weight of the copolymer [A].

Example 7
Instead of coating using a spinner, a pattern was formed in the same manner as in Examples 1 to 6, except that a coating film was prepared from the liquid composition (S-7) of the radiation sensitive resin composition by the dry film method. A thin film was formed and evaluated. Each component is shown in Table 1. The base film was peeled and removed before the exposure process. The evaluation results are shown in Table 2.
Dry film preparation and transfer were performed as follows.
On a polyethylene terephthalate (PET) film having a thickness of 38 μm, a liquid composition (S-1) of a radiation sensitive resin composition was applied using an applicator, the coating film was heated at 100 ° C. for 5 minutes, and a thickness of 4 μm. A radiation-sensitive dry film (J-1) was prepared. Next, the radiation-sensitive transfer dry film is superposed on the surface of the glass substrate so that the surface of the radiation-sensitive transfer layer is in contact, and the radiation-sensitive dry film (J-1) is laminated on the glass substrate by a thermocompression bonding method. Transcribed to.

Example 8
In Example 7, it replaces with the liquid composition (S-7) of a radiation sensitive resin composition, and uses the liquid composition (S-8) of a radiation sensitive resin composition, It is the same as that of Example 7. After producing a radiation-sensitive dry film (J-2), a patterned thin film was formed and evaluated. Each component is shown in Table 1. The evaluation results are shown in Table 2.

In Table 1, the abbreviations of the components indicate the following compounds.
(B-1): KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.)
(B-2): KAYARAD DPHA-40H (manufactured by Nippon Kayaku Co., Ltd.)
(C-1): Ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9. H. -Carbazol-3-yl]-, 1- (O-acetyloxime) (Irgacure OX02 manufactured by Ciba Specialty Chemicals)
(C-2): Ethanone, 1- [9-ethyl-6- [2-methyl-4- (2,2-dimethyl-1,3-dioxolanyl) methoxybenzoyl] -9. H. -Carbazol-3-yl]-, 1- (O-acetyloxime) (N-1919 manufactured by ADEKA)
(C-3): 2-dimethylamino-2- (4-methyl-benzyl) -1- (4-morpholin-4-yl-phenyl) -butan-1-one (manufactured by Ciba Specialty Chemicals) Irgacure 379)
(C-4): 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole (C-5): 4,4′-bis (Diethylamino) benzophenone (C-6): 2-mercaptobenzothiazole (C-7): 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (Ciba Specialty Chemicals) Irgacure 369)
(D-1): Phenol novolac epoxy resin Epicoat 152 (manufactured by Japan Epoxy Resin Co., Ltd.)
In Table 1,-indicates that the component is not added.
The evaluation results are shown in Table 2.

Load-deformation curve for the spacer and load-deformation curve for unloading

Claims (6)

[A] (a1) unsaturated carboxylic acid and / or unsaturated carboxylic acid anhydride,
(A2) an unsaturated compound represented by the following formula (1) or (2),
(A3) A radiation-sensitive resin composition comprising a copolymer of an unsaturated compound other than (a1) and (a2).

(In the formula, R ¹ is a hydrogen atom or a methyl group, R ² is a carboxy group or an isopropyl group, and R ³ is a single bond or a linear or branched alkyl group having 1 to 8 carbon atoms.) The radiation-sensitive resin composition according to claim 1, further comprising [B] a polymerizable unsaturated compound, and [C] a radiation-sensitive polymerization initiator.   The radiation sensitive resin composition of Claim 2 used for formation of the spacer for liquid crystal display elements.   The spacer for liquid crystal display elements formed from the radiation sensitive resin composition of Claim 3. A method for forming a spacer for a liquid crystal display element, comprising at least the following steps in the order described below.
(A) forming a film of the radiation-sensitive resin composition according to claim 3 on a substrate;
(B) exposing at least a part of the coating;
(C) a step of developing the coated film after exposure, and (d) a step of heating the coated film after development.   A liquid crystal display device comprising the spacer according to claim 4.

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