JP2004233975A - Photosensitive resin composition for spacer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition for spacers, which adopts a flow coating method in the case of coating a large-sized substrate for a liquid crystal display, is so excellent in uniformity of coating within the substrate as not to leaving linear traces (including horizontal linear traces and vertical linear traces) and cloudy traces, and ensures a small film thickness variation in the periphery of the substrate. <P>SOLUTION: The photosensitive resin composition for spacers comprises (A) an alkali-soluble resin, (B) a polymerizable compound having an ethylenically unsaturated bond, (C) a photopolymerization initiator and (D) a solvent, and the photosensitive resin composition has a viscosity of 3.0-18.0 cps at 25°C, a solid content of 10-35 wt.% and a contact angle of ≤21° between the photosensitive resin composition and a large-sized substrate for a liquid crystal display. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a spacer photosensitive resin composition for a liquid crystal display which can be suitably applied by applying a casting method when applied to a large substrate for a liquid crystal display. (Including horizontal linear residue and vertical linear residue), no cloud-like residue, excellent coating uniformity inside the substrate, low film thickness deviation around the substrate, and using alkaline developer And a photosensitive resin composition for a spacer which can be developed.

  2. Description of the Related Art Conventionally, in manufacturing a liquid crystal display, it has been known that spacer beads such as glass beads or plastic beads are dispersed between substrates in order to keep a fixed interval between two glass substrates. Since these spacer beads are randomly scattered on the glass substrate, they tend to be always biased toward red (R), green (G), and blue (B) pixel portions, and as a result, incident light is scattered. There is a problem that the contrast of the liquid crystal display is reduced.

  In order to improve these problems, a method of forming a spacer by a photolithography technique has been proposed. According to this method, the photosensitive resin spacer is formed into a dot-like or stripe-like spacer after being developed on the substrate, and R, G, since the spacer can be dispersed or present in an area other than the B pixel, The above problem can be solved. Further, according to this method, the cell gap can be controlled by the thickness of the applied photosensitive resin, so that the cell gap width can be easily controlled and a liquid crystal display (LCD) with high resolution can be obtained.

  On the other hand, in the manufacture of liquid crystal displays, the size of the substrate is inevitably increasing, and the first generation substrate of 320 mm × 400 mm is replaced with the second generation substrate of 370 mm × 470 mm and the third generation substrate of 550 mm × 650 mm. In recent years, a fourth generation substrate of 680 mm × 880 mm to 730 mm × 920 mm has been developed. The purpose of increasing the size of the substrate is to meet the needs of large displays, to reduce manufacturing costs, and the like. In the future, the trend regarding the enlargement of the substrate size is toward the fifth generation or more substrates in which at least one side length is 1000 mm or more. For example, such substrates are 960 mm × 1100 mm, 1100 mm × 1250 mm, 1100 mm × 1300 mm, 1500 mm × 1800 mm, 1800 mm × 2000 mm, and the like.

  When the size of the substrate is 550 mm × 650 mm or less, the photosensitive resin material for the spacer is generally applied onto the substrate by a spin coating method. However, in such a spin coating method, the thickness tends to increase at the peripheral portion of the substrate. As a result, the thickness of the liquid crystal film becomes non-uniform, and when developing the liquid crystal, the hue is non-uniform and the image quality deteriorates. Further, the utilization rate of the photosensitive resin material when using the spin coating method is only 10% or less, so that the photosensitive resin material is wasted and the production efficiency is reduced.

  When the substrate size is 730 mm × 920 mm or more, the coating method of the photosensitive resin material is changed from the spin coating method to the casting-rotation coating method (slit-coating) in order to save the amount of the photosensitive resin material used per unit area. changed to spin coating). In this method, a photosensitive resin material is applied to a substrate by a flow coating method, and then the substrate is rotated to uniformly distribute the photosensitive resin material on the substrate. The advantage of this casting and spin coating method is that the amount of photosensitive resin material used is greatly reduced and the material usage efficiency is about 20% (the material usage efficiency in the spin coating method is about 10%). On the other hand, since it is not possible to unnecessarily remove the extremely thick resist in the peripheral portion of the substrate, there is a disadvantage that the cost of cleaning equipment and cleaning liquid also increases.

  In the future, when the substrate size becomes large and the length of one side becomes at least 1000 mm or more, in order to improve the usage efficiency of the photosensitive resin material, the application method of the photosensitive resin material is “non-rotational application”. It is expected to be used, and for example, the use of a method called casting coating without using spin coating (hereinafter, referred to as a casting coating method) is being studied. For example, Non-Patent Document 1 describes a technique and an apparatus for manufacturing a fifth-generation color filter corresponding to an increase in the size of a substrate using a casting coating method. Non-Patent Document 2 describes that a casting coating apparatus is applied to a liquid crystal display manufacturing technique.

  The above-mentioned casting coating is different from spin coating, in that the utilization efficiency of the photosensitive resin material is 100%, the cost of the photosensitive resin material is greatly reduced, and unnecessary resist components at the peripheral portion of the substrate are eliminated, and cleaning is performed. The disadvantage of increased equipment and cleaning solution costs is improved. As a result, manufacturing costs can be effectively reduced.

However, when the casting coating method is used, there is a problem that a linear residue and a cloud-like residue are easily generated, and the coating uniformity inside the substrate is deteriorated, and the film thickness deviation around the substrate is high. Therefore, it has become difficult to secure uniformity of the entire screen, especially with recent large screens of televisions and personal computers.
Techno Times Co., Ltd., November 2002 issue, Monthly Display, p. 36 Published by the Industrial Research Council, June 2002, separate volume "Electronic Materials" (Japanese version), page 107

  The present invention has been made in view of the above circumstances, and an object thereof is to increase the efficiency of use of a photosensitive resin material and to suppress an increase in manufacturing cost while applying it to a large substrate for a liquid crystal display. , No linear residue (including horizontal and vertical linear residue) and cloud-like residue, excellent coating uniformity inside the substrate, low film thickness deviation around the substrate, and casting An object of the present invention is to provide a photosensitive resin composition for a spacer suitable for a coating method.

The above object is achieved by the photosensitive resin composition for a spacer of the present invention.
That is, the present invention is a photosensitive resin composition for a spacer comprising (A) an alkali-soluble resin, (B) a polymerizable compound having an ethylenically unsaturated bond, (C) a photopolymerization initiator, and (D) a solvent. The photosensitive resin composition has a viscosity at 25 ° C. in the range of 3.0 to 18.0 cps, a solid content of 10 to 35% by weight, and a contact angle between the photosensitive resin composition and a large substrate for a liquid crystal display. Is 21 ° or less.

  Further, the present invention is a photosensitive resin composition for a spacer applied to a large substrate for liquid crystal display by a casting coating method, the photosensitive resin composition for a spacer, (A) an alkali-soluble resin, (B) It contains a polymerizable compound having an ethylenically unsaturated bond, (C) a photopolymerization initiator, and (D) a solvent, the viscosity at 25 ° C. is in the range of 3.0 to 18.0 cps, and the solid content is 10 to 35. By weight, the photosensitive resin composition is a photosensitive resin composition for a spacer having a contact angle with a large substrate for a liquid crystal display of 21 degrees or less.

  As can be seen from Comparative Examples 1 to 3 or Comparative Example 5 described below, when the viscosity of the resin composition exceeds 18.0 cps, the photosensitive resin composition for a spacer of the present invention is applied to a spacer film after pre-baking. A residue remains. Also, as can be seen from the evaluation results of Comparative Examples 4 and 6 described below, when the viscosity of the photosensitive resin composition is less than 3.0 cps, or when the solid content is less than 10% by weight, the spacer film is applied and pre-baked before coating. Cloudy residue is generated on the substrate, and coating uniformity inside the substrate is deteriorated. Further, as can be seen from the evaluation results of Comparative Example 7, when the contact angle between the resin composition and the large substrate exceeds 21 degrees, the thickness deviation of the spacer film formed on the large substrate exceeds 5%. On the other hand, according to the present invention, conditions such as the viscosity of the resin composition, the solid content, the saturated vapor pressure of the solvent (D), and the contact angle between the photosensitive resin composition and the large substrate are adjusted within the scope of the present invention. By doing so, the coating uniformity inside the substrate is excellent, the film thickness deviation around the substrate is low, and the large-sized substrate for liquid crystal display A compatible photosensitive resin composition for a spacer can be provided. Further, according to the present invention, the production efficiency of a large-sized substrate can be approximately doubled as compared with a fourth-generation substrate.

(A) Alkali-soluble resin The alkali-soluble resin (A) in the present invention refers to a resin that is soluble in an alkaline aqueous solution, and includes, for example, a copolymer having a carboxyl group, and a phenol-novolak resin.

  Preferred alkali-soluble resins in the present invention include an unsaturated carboxylic acid monomer forming the structural unit (a1), an epoxy group-containing unsaturated monomer forming the structural unit (a2), and other unsaturated monomers forming the structural unit (a3). It is a copolymer composed of monomers.

  The structural ratio of the structural unit (a1) in the alkali-soluble resin (A) is preferably 5 to 50 parts by weight, and specific examples of the unsaturated carboxylic acid monomer forming the structural unit (a1) Examples include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, α-chloroacrylic acid, ethylacrylic acid and cinnamic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, citracone Unsaturated dicarboxylic acids (anhydrides) such as acid and citraconic anhydride; and trivalent or higher unsaturated polycarboxylic acids (anhydrides). Among these unsaturated carboxylic acid monomers, acrylic acid and methacrylic acid are more preferred. Each unsaturated monomer can be used alone or in combination of two or more.

  The structural ratio of the structural unit (a2) in the alkali-soluble resin (A) is preferably 10 to 70 parts by weight, and specific examples of the epoxy group-containing unsaturated monomer forming the structural unit (a2) are given below. Examples are glycidyl acrylate, glycidyl methacrylate, glycidyl α-ethyl acrylate, 3,4-epoxybutyl acrylate, -6,7-epoxyheptyl methacrylate, α-ethyl acrylate-6,7- Epoxyheptyl, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether and the like can be mentioned. Among these, glycidyl methacrylate, 6,7-epoxyheptyl methacrylate, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether and p-vinylbenzyl glycidyl ether are preferred.

  The structural ratio of the structural unit (a3) in the alkali-soluble resin (A) is preferably 0 to 70 parts by weight, and specific examples of other unsaturated monomers forming the structural unit (a3) Examples are methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate and other methacrylic acid chain alkyl esters; methyl acrylate, acrylate acrylate and other acrylic acid chain alkyl esters; cyclohexyl methacrylate, Cyclic alkyl methacrylates such as 2-methylcyclohexyl methacrylate, dicyclopentanyl methacrylate, dicyclopentanyloxyethyl methacrylate, and isobornyl methacrylate; cyclohexyl acrylate, 2-methylcyclohexyl Acrylic acid cyclic alkyl esters such as acrylate, dicyclopentanyl acrylate, dicyclopentanyloxyethyl acrylate; dicarboxylic acid diesters such as diethyl maleate, diethyl fumarate, diethyl itaconate; 2-hydroxyethyl methacrylate, 2-hydroxy Hydroxyalkyl esters such as propyl methacrylate and 4-hydroxybutyl methacrylate; and styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene and the like. Of these, styrene, t-butyl methacrylate, dicyclopentanyl methacrylate, dicyclopentanyloxyethyl acrylate, and p-methoxystyrene are preferred. Each monomer can be used alone or in combination of two or more.

  Examples of the solvent used in the production of the alkali-soluble resin (A) of the present invention include benzene, toluene, xylene, methanol, ethanol, ethylene glycol monopropyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether. , Methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, methyl ethyl ketone and acetone. Of these, diethylene glycol dimethyl ether and propylene glycol methyl ether acetate are preferred. These solvents can be used alone or in combination.

  For the production of the alkali-soluble resin (A), a general radical polymerization initiator can be used. For example, 2,2′-azobisisobutyronitrile, 2,2′-azobis- (2,4- Azo compounds such as dimethylvaleronitrile), 2,2′-azobis- (4-methoxy-2,4-dimethylvaleronitrile) and 2,2′-azobis-2-methylbutyronitrile, and peroxides such as benzoyl peroxide. Oxides can be used.

The weight average molecular weight of the alkali-soluble resin (A) of the present invention is generally from 3,000 to 100,000, preferably from 4,000 to 80,000, more preferably from 5,000 to 60,000. The molecular weight of the alkali-soluble resin (A) can be controlled by using the alkali-soluble resin alone or by mixing two or more kinds.
In addition, as the alkali-soluble resin (A), by using a copolymer consisting of such monomers (a1) to (a3), the resin (A) is excellent in alkali solubility, and was formed using this The photosensitive resin composition has excellent ultraviolet curability, and can form a spacer having more excellent mechanical and thermal properties.

(B) Polymerizable compound having an ethylenically unsaturated bond In the present invention, the amount of the polymerizable compound (B) having an ethylenically unsaturated bond is preferably 5 to 100 parts by weight of the alkali-soluble resin (A). To 220 parts by weight, more preferably 50 to 140 parts by weight.

  The polymerizable compound (B) having an ethylenically unsaturated bond in the present invention comprises an ethylenically unsaturated compound having one or more ethylenically unsaturated groups. Examples of the ethylenically unsaturated compound having one ethylenically unsaturated group include acrylamide, (meth) acryloylmorpholine, 7-amino-3,7-dimethyloctyl (meth) acrylate, isobutoxymethyl (meth) acrylamide , Isobornyloxyethyl (meth) acrylate, isobornyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ethyldiethylene glycol (meth) acrylate, tert-octyl (meth) acrylamide, diacetone (meth) acrylamide, dimethylaminoethyl ( (Meth) acrylate, dodecyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, N, N-dimethyl (meth) Crylamido, tetrachlorophenyl (meth) acrylate, 2-tetrachlorophenoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, tetrabromophenyl (meth) acrylate, 2-tetrabromophenoxyethyl (meth) acrylate, 2-trichloro Phenoxyethyl (meth) acrylate, tribromophenyl (meth) acrylate, 2-tribromophenoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, vinyl caprolactam, N-vinyl Pyrrolidone, phenoxyethyl (meth) acrylate, pentachlorophenyl (meth) acrylate, pentabromophenyl (meth) acrylate, polyethylene glycol mono ( Data) acrylate, polypropylene glycol mono (meth) acrylate, bornyl (meth) acrylate.

  Examples of the ethylenically unsaturated compound having two or more ethylenically unsaturated groups include ethylene glycol di (meth) acrylate, dicyclopentenyl di (meth) acrylate, triethylene glycol diacrylate, and tetraethylene glycol di (meth) acrylate. Acrylate, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, caprolactone-modified tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, tri Methylolpropane tri (meth) acrylate, ethylene oxide (hereinafter abbreviated as “EO”) modified trimethylolpropane tri (meth) acrylate, propylene oxide (hereinafter abbreviated as “PO”). Modified trimethylolpropane tri (meth) acrylate, tripropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) Acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, polyester di (meth) acrylate, polyethylene glycol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate , Dipentaerythritol tetra (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol Tall penta (meth) acrylate, ditrimethylolpropanetetra (meth) acrylate, EO-modified bisphenol A di (meth) acrylate, PO-modified bisphenol A di (meth) acrylate, EO-modified hydrogenated bisphenol A di (meth) acrylate, PO-modified Examples include hydrogenated bisphenol A di (meth) acrylate, EO-modified bisphenol F di (meth) acrylate, and (meth) acrylate of phenol novolak polyglycidyl ether.

  Among the ethylenically unsaturated compounds, particularly preferred are trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, PO-modified trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate. Examples include acrylate, dipentaerythritol pentaacrylate, dipentaerythritol tetraacrylate, caprolactone-modified dipentaerythritol hexaacrylate, and ditrimethylolpropane tetraacrylate.

(C) Photopolymerization initiator The amount of the photopolymerization initiator (C) used in the present invention is preferably 0.02 to 60 parts by weight per 100 parts by weight of the polymerizable compound having an ethylenically unsaturated bond (B). And more preferably 0.5 to 30 parts by weight.

  The photopolymerization initiator (C) is selected from acetophenone-based compounds and biimidazole-based compounds. Among them, examples of the acetophenone-based compound include p-dimethylaminoacetophenone, α, α′-dimethoxyazoxyacetophenone, 2,2′-dimethyl-2-phenylacetophenone, p-methoxyacetophenone, and 2-methyl- [4- (methylthiophene). ) Phenol], 2-morpholino-1-propanone, 2-benzyl-2-N, N-dimethylamino-1- (4-morpholinophenyl) -1-butanone.

  Examples of the biimidazole compound include 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-fluorophenyl) -4,5, -diphenylimidazole dimer, and 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer. (O-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (2,4-dimethoxyphenyl) -4,5 -Diphenylimidazole dimer, 2- (2-chlorophenyl) -4,5-diphenylimidazole dimer and the like. Among them, 2-benzyl-2-N, N-dimethylamino-1- (4-morpholinophenyl) -1-butanone and 2- (2-chlorophenyl) -4,5-diphenylimidazole dimer are used in combination. The effect of the photopolymerization initiator is relatively preferred.

  The photosensitive resin composition for a spacer of the present invention may further include a photopolymerization initiator of a benzophenone-based compound.Specific examples of the photopolymerization initiator of the benzophenone-based compound include thioxanthone and 2,4-diethylthioxanthone. Thioxanthone-4-sulfone, benzophenone, 4,4'-bis (dimethylamino) benzophenone, and 4,4'-bis (diethylamino) benzophenone. In addition, α-diketones such as benzyl and diacetyl, acyloins such as benzoin, acyloin ethers such as benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether, and 2,4,6-trimethyl-benzoyldiphenylphosphine oxide Acylphosphine oxides such as bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylbenzylphosphine oxide; quinones such as anthraquinone and 1,4-naphthoquinone; phenacyl chloride; tribromomethylphenyl There are halogen compounds such as sulfone and tris (trichloromethyl) -s-triazine, and peroxides such as di-t-butyl peroxide. Of these, benzophenone compounds are preferred, and 4,4'-bis (diethylamino) benzophenone is the most effective.

  The photosensitive resin composition for a spacer of the present invention is obtained by uniformly mixing and preparing an alkali-soluble resin (A), a polymerizable compound having an ethylenically unsaturated bond (B), and a photopolymerization initiator (C). . Usually, a suitable organic solvent is added to the photosensitive resin composition for a spacer of the present invention to dissolve the composition and used in a solution state.

(D) Solvent The solvent used in the present invention is selected from organic solvents which are easily mutually soluble with other organic components. Such a solvent (D) has a saturated vapor pressure at 25 ° C. of 4.5 mm-Hg or less, preferably 4.0 mmHg or less, more preferably 3.8 mmHg or less. When the vapor pressure of the solvent (D) at 25 ° C. is 4.5 mmHg or less, a cloud-like residue hardly occurs after the photosensitive resin composition for a spacer is applied to a large substrate for a liquid crystal display.

  Although a generally known method can be used for measuring the saturated vapor pressure, the saturation vapor pressure of the solvent (D) can be measured more accurately by using the transpiration method (gas flow method) in the present invention.

  The amount of the solvent (D) used in the present invention is 500 to 2,500 parts by weight, more preferably 550 to 2,000 parts by weight, based on 100 parts by weight of the alkali-soluble resin (A).

  As the solvent (D) used in the photosensitive resin composition of the present invention, solvents of ethers and esters can be used, and as ethers, ethylene glycol monopropyl ether, diethylene glycol dimethyl ether, ethylene glycol monomethyl ether , Ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether and the like. On the other hand, examples of esters include methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, and ethyl 3-ethoxypropionate. Of these solvents, diethylene glycol dimethyl ether, propylene glycol methyl ether acetate and ethyl 3-ethoxypropionate are preferred. The solvents may be used alone or in combination of two or more.

  In the photosensitive resin composition for a spacer of the present invention, a surfactant can be used to enhance the coating performance. The amount of the surfactant to be used is generally 0-6 parts by weight, preferably 0-3 parts by weight, per 100 parts by weight of the alkali-soluble resin (A).

  Specific examples of the surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, and the like. Polyoxyethylene alkyl phenyl ethers; polyethylene glycol diesters such as polyethylene glycol dilaurate and polyethylene glycol distearate; sorbitan fatty acid esters; fatty acid-modified polyesters; tertiary amine-modified polyurethanes; (Manufactured by Shin-Etsu Chemical Co., Ltd.), SF-8427 (manufactured by Dow Corning Silicone Toray Co., Ltd.), Polyflow (manufactured by Kyoeisha Yushi Kagaku Kogyo Co., Ltd.) Made-time Products Co., Ltd.), Megafac (manufactured by Dainippon Ink and Chemicals, Inc.), Fluorad (manufactured by Sumitomo 3M Ltd.), mention may be made of Asahi guard, Sarfron (manufactured by Asahi Glass Co., Ltd.), and the like. These surfactants can be used alone or in combination of two or more.

  The photosensitive resin composition for a spacer of the present invention includes various additives as necessary, such as a filler, a polymer compound other than the alkali-soluble resin (A) of the present invention, an adhesion promoter, an antioxidant, and an ultraviolet absorber. , A coagulation inhibitor, a crosslinking agent, a diluent, and the like. In the present invention, the amount of the additive to be used is generally 0 to 10 parts by weight, preferably 0 to 6 parts by weight, more preferably 0 to 3 parts by weight based on 100 parts by weight of the alkali-soluble resin (A). .

  Specific examples of these additives include glass, fillers such as alumina, and polyvinyl alcohol, polyacrylic acid, polyethylene glycol monoalkyl ether, polyfluoroalkyl acrylate, and other high molecular compounds other than the alkali-soluble resin (A), And vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyl Trimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloro Propylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane Orchids, 3-methacryloxypropyltrimethoxysilane, adhesion promoters such as 3-mercaptopropyltrimethoxysilane, and 2,2-thiobis (4-methyl-6-t-butylphenol), 2,6-di-t- Antioxidants such as butylphenol, UV absorbers such as 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole and alkoxybenzophenone, and aggregation prevention such as sodium polyacrylate And a cross-linking agent made of an epoxy compound or resin such as an agent, trade name Epicoat 1031S (Japan Epoxy Resin Co., Ltd.), and a diluent such as trade names RE801 and RE802 (Teikoku Ink).

  The photosensitive resin composition for a spacer of the present invention has a viscosity at room temperature (25 ° C.) of 3.0 to 18.0 cps, preferably 4.0 to 16 cps, and more preferably 5.0 to 14.0 cps. If the viscosity is less than 3.0 cps, cloudy residue is likely to be formed after coating, and the coating uniformity inside the substrate is deteriorated. On the other hand, if the viscosity exceeds 18.0 cps, a linear residue tends to be generated after coating. The viscosity of the photosensitive resin composition was measured at a constant temperature of 25 ° C. using an E-type viscometer at a rotation speed of 6 rpm. The viscosity of the photosensitive resin composition of the present invention can be adjusted or controlled by the types and amounts of the alkali-soluble resin (A), the solvent (D) and the additives.

  The solid content of the photosensitive resin composition for a spacer of the present invention is usually 10 to 35% by weight, preferably 12 to 32% by weight, and more preferably 15 to 30% by weight. If the solid content is less than 10% by weight, cloudy residue is likely to occur after coating, and the coating uniformity inside the substrate deteriorates. If the solid content exceeds 35% by weight, linear residue tends to occur after coating. The solid content was measured by a heating method. In the present invention, the solid content can be adjusted or controlled by the type and amount of the solvent (D), the alkali-soluble resin (A), the polymerizable compound (B) having an ethylenically unsaturated bond, and the additives.

  The photosensitive resin composition for a spacer of the present invention has a contact angle with a large substrate for a liquid crystal display of usually 21 ° or less, preferably 5 to 18 °, more preferably 7 to 15 °. If the contact angle exceeds 21 degrees, the coating uniformity inside the substrate will deteriorate, and the thickness deviation around the substrate will increase. In particular, when the contact angle is in the range of 5 to 18 degrees, the phenomenon of film thickness deviation around the substrate (the phenomenon that the film thickness deviation increases) does not occur. This contact angle can be measured by a droplet method (Sessile Drop method). More specifically, the photosensitive resin composition for a spacer is dropped on a large-sized glass substrate, and the angle after 30 seconds is dropped after the dropping. It can be measured by using a contact angle meter (CA-VP150 type contact angle meter manufactured by Kyowa Interface Science Co., Ltd.). In the present invention, the contact angle is adjusted or controlled by selecting the solvent (D), the type of the alkali-soluble resin (A), and adding an appropriate surfactant or other additives (for example, a diluent). Can be.

  The photosensitive resin composition for a spacer of the present invention is prepared in a solution state by mixing the above components (A) to (D) using various mixers, and then applied to a large substrate by casting. The photosensitive resin composition layer is formed by removing the solvent by pre-baking. Prebaking conditions vary depending on the type and blending ratio of each component, but are usually at 70 ° C to 90 ° C for about 1 minute to 15 minutes. After pre-baking, the photosensitive resin composition layer is exposed through a predetermined pattern mask, and then, for example, is usually developed with a developer at 23 ± 2 ° C. for 30 seconds to 5 minutes to remove unnecessary portions. A predetermined pattern is formed. Ultraviolet rays such as g-rays, h-rays, and i-rays are preferable as the light rays used in the exposure. A high-pressure mercury lamp or a metal halide lamp can be used as the ultraviolet irradiation device.

  As a large-sized substrate, for example, alkali-free glass, soda glass, Pyrex (registered trademark) glass, quartz glass used for a liquid crystal display or the like, a transparent conductive film adhered to these glasses, and a solid-state imaging device are used. A photoelectric conversion element substrate, such as a silicon substrate, may be used. These substrates are generally provided with a black matrix (light shielding film) for isolating each pixel. In addition, the above-mentioned large-sized substrate has a length of at least one side of 800 mm or 800 mm or more, and preferably has a length of at least one side of 1000 mm or 1000 mm or more. The photosensitive resin composition for a spacer can be more preferably used. However, this does not preclude the use of the photosensitive resin composition for a spacer of the present invention on a substrate other than the large-sized substrate, that is, a substrate whose one side does not exceed 800 mm in length. The photosensitive resin composition for a spacer of the present invention enhances the efficiency of use of the photosensitive resin material and suppresses an increase in manufacturing cost, even when used for a substrate whose length of all sides does not exceed 800 mm. However, it does not generate linear residue (including horizontal and vertical linear residue) and cloud-like residue, has excellent coating uniformity inside the substrate, has low film thickness deviation around the substrate, and has low flow. It can be adapted to the roll coating method.

  Examples of the developing solution include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, diethylamine, dimethylethanolamine, and tetramethyl. Alkaline compounds such as ammonium hydroxide, tetraethylammonium hydroxide, choline, pyrrole, piperidine, and 1,8-diazabicyclo- [5,4,0] -7-undecene are used at a concentration of 0.001 to 10% by mass, preferably 0.01 to 10% by mass. An alkaline aqueous solution dissolved to 1% by mass can be used. When a developer composed of such an alkaline aqueous solution is used, the pattern can be generally formed by washing with water after development and further air-drying with compressed air or compressed nitrogen. Thereafter, the pattern is heated by a heating device such as a hot plate or an oven at a predetermined temperature, for example, 150 ° C. to 250 ° C., for a predetermined time, for example, 5 to 60 minutes on a hot plate, and 30 to 90 minutes in an oven (post). By performing baking, a target pixel pattern can be obtained.

  Hereinafter, embodiments of the present invention will be described more specifically with reference to Examples and Comparative Examples. However, the present invention is not limited to these embodiments.

(Synthesis example of alkali-soluble resin (A))
<Synthesis example a>
Under a nitrogen gas atmosphere, 30 parts by weight of methacrylic acid monomer (hereinafter referred to as MAA), Glycidyl monomer (hereinafter referred to as GMA) 25 parts by weight, t-butyl methacrylate monomer (hereinafter referred to as TBMA) 25 parts by weight, styrene monomer (hereinafter referred to as SM) 20 parts by weight, and diethylene glycol dimethyl ether solvent (diglyme) 240 Parts by weight were fed. The feed system for each monomer was a batch addition system. With the contents of the four-necked flask being stirred, the temperature of the oil bath was raised to 85 ° C. Then, 2.4 parts by weight of 2,2'-azobis-2-methylbutyronitrile (AMBN) is dissolved in 20 parts by weight of diethylene glycol dimethyl ether (diglyme), and five equal portions of the solution are transferred four times an hour. It was added to the neck flask. The temperature of the solution was raised to 85 ° C., and this temperature was maintained for 6 hours. After the completion of the polymerization, the polymer was taken out from the four-necked flask, the solvent was volatilized, and the alkali having a weight average molecular weight (Mw) of 31,024 was obtained. A soluble resin a was obtained. The ratio of the structural units derived from each monomer in the alkali-soluble resin a is such that the structural units derived from MAA are 30 parts by weight, the structural units derived from GMA are 25.2 parts by weight, and the structural units derived from TBMA are 25.3 parts by weight, and the structural unit derived from SM was 19.5 parts by weight.

<Synthesis examples b to e>
Except that the kind and the dosage of the monomer and the dosage of the polymerization initiator were changed, alkali-soluble resins b to e were obtained by the same operation method as in Synthesis Example a, and the molecular weight was evaluated. Table 1 shows the production conditions and the weight average molecular weight of the obtained resin.

(Preparation of photosensitive resin composition for spacer)
<Examples 1 to 7 and Comparative Examples 1 to 7>
Using 100 parts by weight (solid content) of the alkali-soluble resin (A) obtained in the above synthesis example, the components shown in Table 2, ie, the polymerizable compound (B) having an ethylenically unsaturated bond, and photopolymerization initiation The agent (C) and other additives were mixed, dissolved and mixed in a solvent (D) to prepare a solution of the photosensitive resin composition for a spacer.

[Evaluation method]
The various photosensitive resin compositions for spacers in Table 2 were mixed with a vibrating stirrer, and then a 15 μm coating film was applied to a large glass substrate of 1100 mm × 960 mm by cast coating, and prebaked at 85 ° C. for 5 minutes. Thereafter, a coating film of the photosensitive resin composition was obtained, and the coating film was evaluated for the following items. The results are shown in Table 2. Then, the photosensitive resin composition coating film was irradiated with ultraviolet rays (exposure machine Canon PLA-501F) at 300 mJ / cm ² through a predetermined pattern mask, immersed in a developer at 23 ± 2 ° C. for 2 minutes, Rinse with pure water. Unnecessary portions were removed by these operations, and further post-baked at 200 ° C. for 40 minutes to obtain a pixel pattern on a glass substrate. And it evaluated according to the following evaluation items, and the result was shown in Table 3.

〔Evaluation item〕
“Viscosity” The viscosity of the photosensitive resin composition was measured at a constant temperature of 25 ° C. using an E-type viscometer (manufactured by Tokyo Seimitsu Co., Ltd.) at a rotation speed of 6 rpm. The unit of the value shown in Table 2 is centipoise (cps).

"Solid Content" 5 cc of the photosensitive resin composition for a spacer was dropped on an aluminum disk and dried at 220 ° C. for 30 minutes. The solid content was calculated from the difference in weight before and after the drying. The unit of the value shown in Table 2 is% by weight.

"Contact angle" The photosensitive resin composition for a spacer is dropped on a large glass substrate by a droplet method, and the angle after 30 seconds from the drop is measured by a contact angle meter (CA-VP150 type contact angle meter manufactured by Kyowa Interface Science Co., Ltd.). It measured using. The units of the values shown in Table 2 are degrees.

“Saturated vapor pressure” was measured at 25 ° C. using a transcription method (gas flow method). The unit of the value shown in Table 2 is mmHg.

"Linear residue" The photosensitive resin composition for a spacer was applied to a large glass substrate of 1100 mm x 960 mm by a casting coating method, and prebaked at 85 ° C for 5 minutes. Obtained. The phenomenon of "linear residue" was visually inspected using a sodium lamp, and evaluated according to the following criteria. Table 3 shows the results. The linear remnants include horizontal linear remnants and vertical linear remnants, and their shapes appear as shown in FIG.
：: no linear residue △: slight linear residue but not remarkable ×: linear residue present

"Cloudy residue" The photosensitive resin composition for a spacer was applied to a large glass substrate of 1100 mm x 960 mm by a casting coating method and prebaked at 85 ° C for 5 minutes. Obtained. The phenomenon of "cloud-like residue" was visually inspected using a sodium lamp, and evaluated according to the following criteria. Table 3 shows the results. The shape of the cloudy residue appears as shown in FIG.
：: No cloudy residue 残: A little cloudy residue but not noticeable ×: Cloudy residue

"Coating uniformity inside substrate" The photosensitive resin composition is applied to a large glass substrate of 1100 mm x 960 mm by a casting coating method and prebaked at 85 ° C for 5 minutes to obtain a coating film of the photosensitive resin composition. Was. The film thickness of the coating film was measured using an α-step type needle contact measuring device manufactured by Tencor. FIG. 2 shows the measurement points of this film thickness.

As the film thickness FT (avg), nine measurement points, that is, (x [mm], y [mm]) are (240,275), (480,275), (720,275), (240,550), (480,550), (720,550) , (240, 825), (480, 825), and the average of the film thickness at the positions of (720, 825), and as FT (x, y) _max , the maximum value of the film thickness at the nine measurement points is obtained. As FT (x, y) _min , the minimum value of the film thickness among the film thicknesses at the above nine measurement points was obtained. The sex was evaluated. Table 3 shows the results.

Equation 1

○：３％未満
△：３〜５％
×：５％を超える

：: less than 3% △: 3 to 5%
×: Over 5%

"Film thickness deviation around substrate" Average value of film thickness at 9 measurement points using an α-step type needle contact measuring device manufactured by Tencor as in the evaluation of "coating uniformity inside substrate". (FT (avg)), and as FT (edge), the film thickness at the position (x [mm], y [mm]) around the substrate (10,550) is obtained. From the calculation results, the film thickness deviation around the substrate was evaluated according to the following criteria. Table 3 shows the evaluation results.

Equation 2

○：３％未満
△：３〜５％
×：５％を超える
「モノマーから誘導される構成単位の比率」 フーリエ変換赤外分光光度計 (Foruier Transform Infrared Spectrometer、Nicolet社製、Nexus 470) により測定し、その結果を表１に示した。表１に示す値の単位は重量部である。
「重量平均分子量 (Mw) 」 ウォーターズ(Waters)社のゲルパーミエーションクロマトグラフィー(GPC)装置を用いて下記の条件で測定した。その測定結果を表１に示す。
カラム：KD−806M
検出器：Water RI-2410
移動相：THF（流速1.0ｃ.ｃ.／min）
標準分子量のポリスチレンを測定基準とする。
以上に述べた内容は、本発明の比較的良い実施例であり、それをもって本発明の実施範囲を限定するものではない。本発明の請求特許の範囲及び発明説明書内容に基づいて行った容易又は均等な変更及び修飾は、すべて本発明の請求特許の範囲に記載した技術の範疇に含まれるものと主張する。

：: less than 3% △: 3 to 5%
X: "Ratio of structural units derived from monomers" exceeding 5%. The measurement was performed using a Fourier transform infrared spectrophotometer (Foruier Transform Infrared Spectrometer, manufactured by Nicolet, Nexus 470). The results are shown in Table 1. The units of the values shown in Table 1 are parts by weight.
"Weight average molecular weight (Mw)" It was measured under the following conditions using a gel permeation chromatography (GPC) apparatus manufactured by Waters. Table 1 shows the measurement results.
Column: KD-806M
Detector: Water RI-2410
Mobile phase: THF (flow rate 1.0 cc / min)
Polystyrene having a standard molecular weight is used as a measurement standard.
The above description is a comparatively good embodiment of the present invention, and does not limit the scope of the present invention. All easy or equivalent changes and modifications made on the basis of the scope of the claims and the description of the invention are claimed to be included in the scope of the technology described in the claims of the invention.

B-1 ジペンタエリスリトールヘキサアクリレート
B-2 ジペンタエリスリトールテトラアクリレート
B-3 ＰＯ変性グリセロールトリアクリレート
C-1 2-ベンジル-2-N,N-ジメチルアミノ-1-(4-モルホリノフェニル)-1-ブタノン
C-2 4,4’- ビス(ジエチルアミノ）ベンゾフェノン
C-3 2,2’-ビス(2-クロロアミノ)-4,4’,5,5’-テトラフェニルビイミダゾール
Diglyme ジエチレングリコールジメチルエーテル
PGMEA プロピレングリコールメチルエーテルアセテート
EEP エチル3-エトキシプロピオネート
γ-butyrolactone γ-ブチロラクトン
n-butyl acetate n−ブチルアセテート
界面活性剤-1 商品名フロラード(住友3M社製)
界面活性剤-2 商品名SF-8427(東レダウコーニングシリコーン社製)
密着促進剤-1 3-メタクリロキシプロピルトリメトキシシラン
架橋剤-1 商品名1031S(ジャパンエポキシ社製)
希釈剤-1 商品名RE801（帝国インキ社製）

B-1 Dipentaerythritol hexaacrylate
B-2 dipentaerythritol tetraacrylate
B-3 PO-modified glycerol triacrylate
C-1 2-benzyl-2-N, N-dimethylamino-1- (4-morpholinophenyl) -1-butanone
C-2 4,4'-bis (diethylamino) benzophenone
C-3 2,2'-bis (2-chloroamino) -4,4 ', 5,5'-tetraphenylbiimidazole
Diglyme diethylene glycol dimethyl ether
PGMEA Propylene glycol methyl ether acetate
EEP Ethyl 3-ethoxypropionate γ-butyrolactone γ-butyrolactone
n-butyl acetate n-butyl acetate surfactant-1 trade name Florard (Sumitomo 3M)
Surfactant-2 trade name SF-8427 (Toray Dow Corning Silicone Co., Ltd.)
Adhesion promoter-1 3-methacryloxypropyltrimethoxysilane crosslinking agent-1 Trade name 1031S (manufactured by Japan Epoxy)
Diluent-1 Trade name RE801 (manufactured by Teikoku Ink)

Schematic showing linear and cloudy residues Schematic diagram showing measurement points of film thickness

Claims (4)

A photosensitive resin composition for a spacer applied to a large-sized substrate for liquid crystal display by a casting coating method, wherein the photosensitive resin composition for a spacer is:
(A) an alkali-soluble resin,
(B) a polymerizable compound having an ethylenically unsaturated bond,
(C) a photopolymerization initiator, and
(D) containing a solvent,
The viscosity at 25 ° C. is in the range of 3.0 to 18.0 cps, the solid content is 10 to 35% by weight, and the photosensitive resin composition has a contact angle with a large liquid crystal display substrate of 21 ° or less. A photosensitive resin composition for a spacer.   2. The photosensitive resin composition for a spacer according to claim 1, wherein the solvent (D) has a saturated vapor pressure at 25 ° C. of 4.5 mm-Hg or less.   The alkali-soluble resin (A) is (a1) a structural unit derived from an unsaturated carboxylic acid monomer, (a2) a structural unit derived from an epoxy group-containing unsaturated monomer, and (a3) the (a1) and ( 2. The photosensitive resin composition for a spacer according to claim 1, which is a copolymer comprising a structural unit derived from an olefinically unsaturated monomer other than a2).   The photosensitive resin composition for a spacer according to claim 1, wherein the large-sized substrate for a liquid crystal display has a length of at least one side of 800 mm or 800 mm or more.

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