KR20040107392A - Spacer for Display Panels, Radiation Sensitive Resin Composition and Liquid Crystal Display Device - Google Patents

Abstract

PURPOSE: A spacer for display panels, a radiation sensitive resin composition and a liquid crystal display device are provided to maintain the width between the substrates constant at a room temperature and at a high temperature. CONSTITUTION: A radiation sensitive resin composition includes a copolymer with (a1) a unsaturated carboxylic acid and a unsaturated carboxylic anhydride and (a2) a unsaturated composition except the component (a1), a multi-functional unsaturated monomers and a radiation sensitive polymer initiator. In the radiation sensitive resin, the linear thermal expansion coefficient is larger than 2.0 x 10-4/°C and smaller than 8.0 x 10-4/°C.

Description

Display panel spacer, radiation sensitive resin composition and liquid crystal display device {Spacer for Display Panels, Radiation Sensitive Resin Composition and Liquid Crystal Display Device}

This invention relates to the spacer for display panels, a radiation sensitive resin composition, and a liquid crystal display element. More specifically, the present invention relates to a display panel spacer used for a liquid crystal display panel, a touch panel, and the like, a radiation-sensitive resin composition used for forming the spacer, and a liquid crystal display device including the spacer.

Conventionally, spacer particles such as glass beads or plastic beads having a predetermined diameter have been used in liquid crystal display panels in order to keep the gap width between two substrates constant. However, since the spacer particles are randomly scattered on the substrate, when the spacer is present in the effective pixel region, the spacer particles form an image or scatter incident light, thereby reducing the contrast of the liquid crystal display panel.

Thus, the spacer is formed by photolithography. In this technique, the substrate is coated with a photosensitive resin, exposed to ultraviolet light through a predetermined mask, and developed to form a dot or stripe spacer. According to this technique, a spacer can be formed in a region other than the effective pixel region, so that the above-described problem occurring when the spacer particles are dispersed can be solved. In addition, in this technique, since the cell gap can be adjusted by the coating film thickness of the photosensitive resin, adjustment of the gap width is easy and high precision can be obtained.

The gap width between the substrates of the liquid crystal display panel is maintained at a constant value by the spacers disposed between the substrates at room temperature, and thus the thickness of the liquid crystal layer between the substrates is kept constant. However, when the liquid crystal display panel is placed at a high temperature in the annealing step after the liquid crystal injection and sealing in the liquid crystal display panel manufacturing process and the high temperature standing test for evaluating the reliability of the liquid crystal display panel, the liquid crystal enclosed between the substrates is heated. By expanding and changing the gap width by the expansion pressure, the substrate is distorted and the liquid crystal layer thickness is partially uneven. Therefore, the display contrast is uneven and the display quality deteriorates. In particular, in a large liquid crystal display panel having a large substrate area, the distortion of the substrate due to thermal expansion of the liquid crystal tends to be remarkable. Since the liquid crystal display panel for TV is enlarged, the non-uniform display contrast by the thermal expansion of a liquid crystal becomes a serious problem which should be solved.

There are various proposals for reducing uneven display contrast caused by thermal expansion of liquid crystals.

Japanese Patent Application Laid-Open No. 8-15708 (the term "Japanese Patent Publication" as used herein means "unexamined published Japanese patent application") discloses a method using a plurality of spherical spacers having different diameters and elastic moduli. It is. Japanese Patent Laid-Open No. 2002-49041 discloses a method for adjusting the dispersion density of a spherical spacer in the process conditions for assembling a display panel. Japanese Patent Laid-Open No. 2001-147437 discloses an arrangement of columnar spacers.

However, when the liquid crystal display panel is tilted from the horizontal direction at a high temperature, since the spherical spacer particles do not adhere to the substrate surface, the particles move in the liquid crystal layer and are unevenly distributed, resulting in display unevenness. Defining the placement of the columnar spacers limits the degree of freedom of panel design, and is not feasible as the design of liquid crystal display panels will be increasingly diversified in the future.

SUMMARY OF THE INVENTION An object of the present invention is for a display panel having a specific linear thermal expansion coefficient, which can maintain a uniform width between the substrates at room temperature and at a high temperature, and can always ensure excellent display quality without being affected by temperature changes. It is providing the liquid crystal display element containing a spacer, the radiation sensitive resin composition used for the said spacer formation, and the said spacer.

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

According to the present invention, firstly, the above objects and advantages of the present invention are achieved by spacers for display panels having a linear thermal expansion coefficient greater than 2.0 × 10 ⁻⁴ / ° C. and below 8.0 × 10 ⁻⁴ / ° C.

According to the present invention, secondly, the above objects and advantages of the present invention,

(A) a copolymer of (a1) unsaturated carboxylic acid and / or unsaturated carboxylic anhydride with (a2) unsaturated compounds other than said component (a1),

[B] polyfunctional unsaturated monomers, and

[C] a radiation sensitive resin composition comprising a radiation sensitive polymerization initiator, wherein the linear thermal expansion coefficient of the cured film of the radiation sensitive resin composition is greater than 2.0 × 10 ⁻⁴ / ° C. greater than 8.0 × 10 ⁻⁴ / ° C. Hereinafter, the said radiation sensitive resin composition is used to form the spacer for display panels of Claim 1.

According to the present invention, thirdly, the above objects and advantages of the present invention are achieved by a liquid crystal display element comprising the spacer for a display panel of the present invention.

<Detailed Description of the Preferred Embodiments>

The present invention is described in detail below.

Display panel spacer

The linear thermal expansion coefficient of the spacer for a display panel of the present invention is more than 2.0 × 10 ^-4 / ℃ 8.0 × 10 ^-4 / ℃ or less, preferably (3.0 to 8.0) × 10 ^-4 / ℃, more preferably ( 4.0 to 8.0) × 10 ⁻⁴ / ° C., particularly preferably (5.0 to 8.0) × 10 ⁻⁴ / ° C.

The display panel spacer of the present invention can maintain a constant width between the substrates at room temperature and high temperature when its linear thermal expansion coefficient is within the above range, and always exhibit excellent display quality without being affected by temperature change. It can be secured and can be advantageously used in liquid crystal display panels, touch panels, and the like without limiting the shape and position of spacers and the degree of freedom of panel design.

Radiation-sensitive resin composition

The material used to form the display panel spacer of the present invention may have a linear thermal expansion coefficient and strength, surface hardness, heat resistance, and chemical resistance required as the spacer, and can form a spacer having a predetermined shape. It is not specifically limited. Preferred materials are

[A] (a1) unsaturated carboxylic acid and / or unsaturated carboxylic anhydride (hereinafter referred to as "acidic unsaturated compound (a1)") and (a2) unsaturated compounds other than said component (a1) (hereinafter, Copolymer with "other unsaturated compounds (a2)") (hereinafter referred to as "copolymer [A]"),

[B] polyfunctional unsaturated monomers, and

[C] A radiation-sensitive resin composition containing a radiation-sensitive polymerization initiator, wherein the linear thermal expansion coefficient of the cured film obtained therefrom is greater than 2.0 × 10 ⁻⁴ / ° C. and 8.0 × 10 ⁻⁴ / ° C. or less.

Copolymer [A]-

Examples of the acidic unsaturated compound (a1) used for the copolymer [A] include unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid; Unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid and itaconic acid; And anhydrides of these unsaturated dicarboxylic acids.

Among these acidic unsaturated compounds (a1), acrylic acid, methacrylic acid and maleic anhydride are preferred from the viewpoint of copolymerization reactivity and availability.

The acidic unsaturated compound (a1) may be used alone or in a mixture of two or more thereof.

Examples of the other unsaturated compound (a2) used in the copolymer [A] include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, alkyl (meth) acrylates such as n-butyl (meth) acrylate, i-butyl (meth) acrylate, sec-butyl (meth) acrylate and t-butyl (meth) acrylate; Cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-methylcyclohexyl (meth) acrylate, tricyclo [5.2.1.0 ^2,6 ] decane-8-yl (meth) acrylate, 2- Alicyclic (meth) acrylates such as dicyclopentanyloxyethyl (meth) acrylate and isobornyl (meth) acrylate; Aryl (meth) acrylates such as phenyl (meth) acrylate and benzyl (meth) acrylate; Hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; Glycidyl (meth) acrylate, 3,4-epoxybutyl (meth) acrylate, 6,7-epoxyheptyl (meth) acrylate, 2,3-epoxycyclopentyl (meth) acrylate, 3,4- Epoxy group-containing (meth) acrylates such as epoxycyclohexyl (meth) acrylate; Unsaturated dicarboxylic acid diesters such as diethyl maleate, diethyl fumarate, diethyl itaconate; Unsaturated imide compounds such as N-phenylmaleimide, N-benzyl maleimide, and N-cyclohexyl maleimide; Vinyl cyanide compounds such as (meth) acrylonitrile, α-chloroacrylonitrile and vinylidene cyanide; Unsaturated amide compounds such as (meth) acrylamide and N, N-dimethyl (meth) acrylamide; Aromatic vinyl compounds such as styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene and p-methoxystyrene; Indene derivatives such as indene and 1-methylindene; Conjugated diene compounds such as 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, and vinyl chloride, vinylidene chloride, vinyl acetate and the like.

Alicyclic (meth) acrylates, such as alkyl (meth) acrylates, such as n-butyl (meth) acrylate, and tricyclo [5.2.1.0 ^2,6 ] decan-8-yl, in these other unsaturated compounds (a2). Aryl (meth) acrylates such as benzyl (meth) acrylate, epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate, styrene and 1,3-butadiene from the viewpoint of copolymerization reactivity desirable.

The said other unsaturated compound (a2) can be used individually or in mixture of 2 or more types.

The content of the repeating unit derived from the acidic unsaturated compound (a1) in the copolymer [A] is preferably 5 to 50% by weight, particularly preferably 10 to 40% by weight. When the content of the repeating unit is less than 5% by weight, heat resistance, chemical resistance and surface hardness of the spacer may be deteriorated, and when the content of the repeating unit is more than 50% by weight, the storage stability of the composition may be lowered.

The polystyrene reduced weight average molecular weight (hereinafter referred to as "Mw") of the copolymer [A] is preferably 2,000 to 500,000, more preferably 5,000 to 100,000. When Mw of copolymer [A] is less than 2,000, heat resistance and surface hardness may fall, and when Mw is more than 500,000, developability may deteriorate.

In the present invention, the copolymer [A] can be used alone or in a mixture of two or more thereof.

Copolymer [A] can be manufactured by polymerizing an acidic unsaturated compound (a1) and another unsaturated compound (a2) in a solvent in presence of a polymerization initiator.

Examples of the solvent used for the preparation of the copolymer [A] include

Alcohols such as methanol and ethanol; Ethers such as tetrahydrofuran and dioxane; Ethylene glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether and ethylene glycol mono-n-butyl ether; Ethylene glycol alkyl ether acetates such as ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol-n-propyl ether acetate and ethylene glycol-n-butyl ether acetate; Diethylene glycol ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether; Diethylene glycol alkyl ether acetates such as diethylene glycol methyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol-n-propyl ether acetate, diethylene glycol-n-butyl ether acetate; Propylene glycol ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether and propylene glycol mono-n-butyl ether; Propylene glycol alkyl ether acetates such as propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol-n-propyl ether acetate and propylene glycol-n-butyl ether acetate; Propylene glycol alkyl ether propionates such as propylene glycol methyl ether propionate, propylene glycol ethyl ether propionate, propylene glycol-n-propyl ether propionate, and propylene glycol-n-butyl ether propionate; Aromatic hydrocarbons such as toluene and xylene; Ketones such as methyl ethyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, and methyl isoamyl ketone; And methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl hydroxyacetate, ethyl hydroxyacetate, n-propyl hydroxyacetate, n-butyl hydroxyacetate, methyl methoxyacetate, ethyl methoxyacetate , n-propyl methoxy acetate, n-butyl methoxy acetate, methyl ethoxy acetate, ethyl ethoxy acetate, n-propyl ethoxy acetate, n-butyl ethoxy acetate, methyl n-propoxy acetate, ethyl n-prop Poxycyacetate, n-propyl n-propoxyacetate, n-butyl n-propoxyacetate, methyl n-butoxyacetate, ethyl n-butoxyacetate, n-propyl n-butoxyacetate, n-butyl n-part Oxyacetate, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, methyl 3-hydroxypropionate, ethyl 3-hydroxy Ropionate, n-propyl 3-hydroxypropionate, n-butyl 3-hydroxypropionate, methyl 2-methoxypropionate, ethyl2-methoxypropionate, n-propyl 2-meth Oxypropionate, n-butyl 2-methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate, n-propyl 2-ethoxypropionate, n-butyl 2- Ethoxypropionate, methyl 2-n-propoxypropionate, ethyl 2-n-propoxypropionate, n-propyl 2-n-propoxypropionate, n-butyl 2-n-propoxy Propionate, methyl 2-n-butoxypropionate, ethyl 2-n-butoxypropionate, n-propyl 2-n-butoxypropionate, n-butyl 2-n-butoxypropionate Acetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, n-propyl 3-methoxypropionate, n-butyl 3-methoxypropionate, Methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, n-propyl 3-ethoxypropionate, n-butyl 3-ethoxypropionate, methyl 3-n-propoxypropionate , Ethyl 3-n-propoxypropionate, n-propyl 3-n-propoxypropionate, n-butyl 3-n-propoxypropionate, methyl 3-n-butoxypropionate, ethyl 3-n-butoxypropionate, n-propyl 3-n-butoxypropionate, n-butyl 3-n-butoxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl Other esters such as 2-hydroxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutanoate, and the like.

These solvents may be used alone or in a mixture of two or more thereof.

As a polymerization initiator used for the synthesis | combination of copolymer [A], generally well-known radical polymerization initiator can be used. Examples of the radical polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobis- (4-meth Azo compounds such as methoxy-2,4-dimethylvaleronitrile); Organic peroxides such as benzoyl peroxide, lauroyl peroxide, t-butylperoxy pivalate, 1,1'-bis- (t-butylperoxy) cyclohexane; Hydrogen peroxide; And a redox polymerization initiator including one of the peroxide and the reducing agent.

These polymerization initiators can be used individually or in mixture of 2 or more types.

-[B] polyfunctional unsaturated monomer-

A polyfunctional unsaturated monomer is a monomer which has two or more polymerizable unsaturated bonds. Preferred examples of such polyfunctional unsaturated monomers include polyfunctional (meth) acrylic acid esters which may have a urethane bond.

Among the polyfunctional (meth) acrylic acid esters, examples of the difunctional (meth) acrylic acid esters include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and 1,6-hexanediol di (meth) acrylic acid. Latex, 1,9-nonanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth ) Acrylate, bisphenoxyethanol fluorene di (meth) acrylate.

Commercially available products of difunctional (meth) acrylic acid esters include Aronix M-210, 240 and 6200 (manufactured by Toagosei Chemical Industry Co., Ltd.), KAYARAD HDDA. , HX-220 and R-604 (manufactured by Nippon Kayaku Co., Ltd.), and Biscoat 260, 312 and 335HP (Osaka Yuki Kagaku Co., Ltd. Commercially available products of difunctional (meth) acrylic acid esters having urethane bonds include Aronix M-1100, 1200, 1210, 1310 and 1600 (manufactured by Toagosei Chemical Industries, Ltd.), R-1000 series , 1204, 1211 and 1213 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), and AH-600, AT-600 and UA-306H (Kyoeisha Kagaku Co.) ., Ltd.)).

Commercially available products of (meth) acrylic acid esters having three or more functional groups include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate and dipentaerytate. Lititol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate and tri [2- (meth) acryloyloxyethyl] phosphate.

Commercially available products of (meth) acrylic acid esters having three or more functional groups include Aronix M-309, 400, 402, 405, 450, 7100, 8030, 8060, 1310, 1600, 1960, 8100, 8530, 8560 and 9050 , Aronix TO-1450 (manufactured by Toagosei Chemical Industries, Ltd.), Gayarad TMPTA, Gayarad DPHA, DPCA-20, DPCA-30, DPCA-60, DPCA-120 and MAX-3510 (manufactured by Nippon Kayaku Co., Ltd.) Commercially available products of trifunctional (meth) acrylic acid esters, including biscots 295, 300, 360, 400, GPT, and 3PA (manufactured by Osaka Kagaku Co., Ltd.) and having a urethane bond, are R-1000 series, 1301, 1302. , 1303, 1304, 1306 and 1308 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and commercially available products of (meth) acrylic acid esters having a urethane bond and four or more functional groups include Aronix M-1960 (Doagosei Chemical Industries) Company) and R-1150 (made by Daiichi Kogyo Seiyaku Co., Ltd.).

In the present invention, the polyfunctional unsaturated monomers may be used alone or in mixture of two or more thereof. The polyfunctional unsaturated monomer preferably contains a polyfunctional (meth) acrylic acid ester having a urethane bond, and more preferably a polyfunctional (meth) having no urethane bond with a polyfunctional (meth) acrylic acid ester having a urethane bond. Mixtures with acrylic esters. By using the polyfunctional unsaturated monomer containing the polyfunctional (meth) acrylic acid ester which has a urethane bond, the radiation sensitive resin composition with a high linear thermal expansion coefficient can be obtained.

In a polyfunctional unsaturated monomer containing a polyfunctional (meth) acrylic acid ester having a urethane bond, the amount of the polyfunctional (meth) acrylic acid ester having a urethane bond is preferably 10 to 50% by weight, more preferably 15 to 50 It is weight%, Especially preferably, it is 25-50 weight%. When the polyfunctional (meth) acrylic acid ester having a urethane bond is contained in the above amount, properties such as sensitivity, developability, strength and the like during exposure of the spacer are not impaired.

-[C] radiation sensitive polymerization initiator-

The radiation sensitive polymerization initiator reacts with radiation to produce active species capable of initiating polymerization of the polyfunctional unsaturated monomer [B].

Preferably, the radiation sensitive polymerization initiator is a radiation sensitive radical polymerization initiator.

Examples of the radiation-sensitive radical polymerization initiator include α-diketones such as benzyl and diacetyl; Acyl phosphorus such as benzoin; Acyloin ethers such as benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether; Thioxanthone, 2,4-diethyl thioxanthone, thioxanthone-4-sulfonic acid, benzophenone, 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) benzo Benzophenones such as phenone; Acetophenone, p-dimethylaminoacetophenone, 4- (α, α'-dimethoxyacetoxy) benzophenone, 2,2'-dimethoxy-2-phenylacetophenone, p-methoxyacetophenone, 2-methyl Aceto, such as 2-morpholino-1- (4-methylthiophenyl) -1-propanone and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one Phenones; Quinones such as anthraquinone and 1,4-naphthoquinone; Halogen compounds such as phenacyl chloride, tribromomethylphenyl sulfone and tris (trichloromethyl) -s-triazine; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) Acylphosphine oxides such as phenylphosphine oxide; And peroxides such as di-t-butylperoxide and the like.

Commercially available products of radiation-sensitive radical polymerization initiators include IRGACURE-124, 149, 184, 369, 500, 651, 819, 907, 1000, 1700, 1800, 1850, and 2959, Darocur. -1116, 1173, 1664, 2959 and 4043 (manufactured by Ciba Specialty Chemicals Co., Ltd.), Kayakure-DETX, -MBP, -DMBI, -EPA and -OA (Nippon Kaya Co., Ltd.), LUCIRIN TPO (manufactured by BASF Co., Ltd.), VICURE-10 and 55 (manufactured by STAUFFER Co., Ltd.), Trignalp 1 ( TRIGGNALP1) (manufactured by AKZO Co., Ltd.), SANDORAY 1000 (manufactured by SANDOZ AG), DEAP (manufactured by APJOHN Co., Ltd.) And QUANTACURE-PDO, -ITX and -EPD (manufactured by WARD BLEKINSOP Co., Ltd.).

These radiation-sensitive radical polymerization initiators can be used individually or in mixture of 2 or more types.

Moreover, by using at least 1 type of radiation sensitive sensitizer with the said radiation sensitive radical polymerization initiator, the radiation sensitive resin composition which has little inactivation by the oxygen contained in air, and has high sensitivity can be obtained.

In the amount of each component of the radiation-sensitive resin composition of the present invention, the amount of the polyfunctional monomer [B] is preferably 10 to 150 parts by weight, more preferably 20 to 120 to 100 parts by weight of the copolymer [A]. It is weight part, and the quantity of a radiation sensitive polymerization initiator [C] is 1-40 weight part with respect to 100 weight part of copolymers [A], More preferably, it is 3-35 weight part.

If the amount of the multifunctional monomer [B] is less than 10 parts by weight, it may be difficult to form a uniform coating film, and if the amount of the multifunctional monomer [B] is more than 150 parts by weight, the adhesion to the substrate Can be degraded. Heat resistance, surface hardness and chemical resistance may deteriorate when the amount of radiation-sensitive polymerization initiator [C] is less than 1 part by weight, and transparency may decrease when the amount of radiation-sensitive polymerization initiator [C] is greater than 40 parts by weight. Can be.

Other additives

The radiation sensitive resin composition of this invention can contain other additives, such as surfactant and an adhesion | attachment adjuvant, in the range which does not impair the objective of this invention.

The surfactant is used to improve the applicability.

Preferably, the surfactant is a fluorine-based surfactant or a silicone-based surfactant.

Preferably, the fluorine-based surfactant is a compound having a fluoroalkyl group or a fluoroalkylene group at any one of the terminal, the main chain and the side chain. Examples of the fluorine-based surfactants include 1,1,2,2-tetrafluoropropyl (1,1,2,2-tetrafluorooctyl) ether and hexyl (1,1,2,2-tetrafluorooctyl) Ether, octaethylene glycol di (1,1,2,2-tetrafluorobutyl) ether, hexaethylene glycol di (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 Fluoroalkylphosphonates, sodium fluoroalkylcarbonates, fluoroalkylpolyoxyethylene ethers, diglycerine tetrakis (fluoroalkylpolyoxyethylene ethers), fluoroalkylammonium iodides, fluoroalkyl betaines , Fluoroal Polyoxyethylene ethers include perfluoroalkyl polyoxyethylene ethanol, perfluoroalkyl alkoxylate and fluorinated alkyl esters.

Commercially available products of the fluorine-based surfactants include BM-1000 and 1100 (manufactured by BM CHEMIE Co., Ltd.), Megafac F142D, F172, F173, F178, F183, F191, F471 and F476 (manufactured by Dainippon Ink and Chemicals, Inc.), Florade FC-170C, 171, 430 and 431 (manufactured by Sumitomo 3M Limited), supple Surflon S-112, 113, 131, 141, 145 and 382, Suflon SC-101, 102, 103, 104, 105 and 106 (manufactured by AsahiGlass Co., Ltd.), f-top (F Top) EF301, 303, and 352 (manufactured by Shin Akita Kasei Co., Ltd.), Futargent FT-100, 110, 140A, 150, 250, 251, 300, 310 and 400S, and Futagent FTX-251 and 218 (manufactured by Neos Co., Ltd.) and the like.

Commercially available products of the silicone surfactant include Toray Silicone DC3PA, DC7PA, SH11PA, SH21PA, SH28PA, SH29PA, SH30PA, SH-190, SH-193, SZ-6032, SF-8428, DC-57 and DC-190 (manufactured by Toray Dow Corning Silicone Co., Ltd.), and TSF-4300, 4440, 4445, 4446, 4452 and 4460 (GE Toshiba Silicone Co., Ltd.) .) Manufacturing).

Other surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether and polyoxyethylene oleyl ether; Polyoxyethylene aryl ethers such as polyoxyethylene-n-octylphenyl ether and polyoxyethylene-n-nonylphenyl ether; And nonionic surfactants such as polyoxyethylene dialkyl esters such as polyoxyethylene dilaurate and polyoxyethylene distearate; And organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.) and (meth) acrylic acid copolymer polyflow No. 57 and No. 95 (manufactured by Kyoeisha Chemical Co., Ltd.) and the like.

These surfactants can be used alone or as a mixture of two or more thereof.

The amount of the surfactant is preferably 5 parts by weight or less, more preferably 2 parts by weight or less based on 100 parts by weight of the copolymer [A]. If the amount of the surfactant exceeds 5 parts by weight, the film may become rough upon application.

The adhesion aid is used to improve the adhesion to the substrate.

Preferably, the adhesion aid is a silane coupling agent having a functional group, specifically a functional group such as a carboxyl group, methacryloyl group, isocyanate group or epoxy group. Examples of the adhesion aid include trimethoxysilylbenzoic acid, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, and γ-gly Cydoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyl trimethoxysilane, and the like.

These adhesion aids can be used individually or in mixture of 2 or more types.

The amount of the adhesion aid is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, based on 100 parts by weight of the copolymer [A]. When the amount of the adhesive aid exceeds 20 parts by weight, the heat resistance may be lowered.

In the radiation sensitive resin composition of the present invention, the copolymer [A], the polyfunctional unsaturated monomer [B], the radiation sensitive polymerization initiator [C] and other additives and the amounts of these components are linear thermal expansion coefficients of the cured film obtained therefrom. Is greater than 2.0 × 10 ⁻⁴ / ° C. or less 8.0 × 10 ⁻⁴ / ° C. or less, preferably (3.0 to 8.0) × 10 ⁻⁴ / ° C., more preferably (4.0 to 8.0) × 10 ⁻⁴ / ° C., in particular Preferably it is chosen suitably so that it is (5.0-8.0) * 10 <^-4> / ^degreeC .

Preparation of radiation sensitive resin composition

Preferably, the radiation sensitive resin composition of the present invention mixes the copolymer [A], the polyfunctional monomer [B] and the radiation polymerization initiator [C], and optionally other additives together, and these components are mixed in a suitable solvent. It is prepared as a composition solution by dissolving.

The solvent used to prepare the composition solution preferably dissolves the components and does not react with these components.

Examples of the solvent are the same as those described above as the solvent used for producing the copolymer [A].

Of these solvents, ethylene glycol ethers, ethylene glycol alkyl ether acetates, diethylene glycol ethers, propylene glycol alkyl ether acetates, and other esters are preferable in view of solubility, reactivity with each component, and ease of coating film formation. .

The solvents may be used alone or in a mixture of two or more thereof.

High boiling point solvents can be used with the solvent.

Examples of high boiling point solvents include N-methylformamide, N, N-dimethylformamide, N-methylformanilide, N-methylacetamide, N, N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide Seed, benzyl ethyl ether, dihexyl ether, acetonyl acetone, isophorone, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, di Ethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, phenylcellosolve acetate.

These high boiling point solvents can be used individually or in mixture of 2 or more types.

The composition solution prepared as described above is used after filtration using a Millipore filter having a pore size of about 0.2 to 0.5 μm.

Formation Method of Spacer for Display Panel

Below, the method of forming the spacer for display panels of this invention from the radiation sensitive resin composition of this invention is demonstrated.

First, the composition solution is applied to the substrate surface to form a coating film.

The composition solution can be applied by a suitable method such as spraying, roll coating, rotary coating, bar coating or inkjet coating.

Thereafter, the coating film is prebaked to evaporate the solvent to obtain a film having no fluidity.

The prefiring conditions which depend on the kind and amount of each component are generally 60-120 degreeC and time of 10-600 second.

Thereafter, the film is exposed to radiation through a mask having a predetermined pattern, and developed with a developer to remove unnecessary portions.

The radiation used for exposure is visible light, ultraviolet light, far ultraviolet rays, electron beams, X-rays, or the like, and is preferably ultraviolet light having a wavelength of 190 to 450 nm.

The exposure dose is preferably 100 to 20,000 J / m ² , more preferably 150 to 10,000 J / m ² .

The developer includes inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate or aqueous ammonia; Primary amines such as ethylamine or n-propylamine; Secondary amines such as diethylamine or di-n-propylamine; Tertiary amines such as triethylamine, methyldiethylamine or N-methylpyrrolidone; Alcohol amines such as dimethylethanolamine or triethanolamine; Quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide or choline; It may be an aqueous alkali solution such as cyclic amines such as pyrrole, piperidine, 1,8-diazabicyclo [5.4.0] -7-undecene or 1,5-diazabicyclo [4.3.0] -5-nonene have.

The aqueous alkali solution may contain a suitable amount of water-soluble organic solvents such as methanol or ethanol and surfactants.

Preferably the development is carried out at room temperature for 30 to 180 seconds.

The developing method may be puddle developing, dipping or spraying.

After development, running water cleaning is performed for 30 to 90 seconds, and water is removed by spraying compressed air or compressed nitrogen to obtain a film having a predetermined pattern.

Then, a spacer having a predetermined shape can be obtained by heating and curing with a heating apparatus such as a hot plate or an oven at 150 to 250 ° C., for example, for 5 to 30 minutes on a hot plate and for 30 to 90 minutes in an oven. have.

<Example>

The following examples are provided to illustrate the invention, but are not limited to these examples.

Synthesis Example 1

Into a flask equipped with a stirrer was charged 4 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) and 200 parts by weight of diethylene glycol ethyl methyl ether, 5 parts by weight of 1,3-butadiene and 18 parts by weight of methacrylic acid Part, 40 parts by weight of benzyl methacrylate and 37 parts by weight of n-butyl methacrylate were further injected into the flask, the inside of the flask was replaced with nitrogen, these materials were gently stirred, and the temperature of the reaction solution was raised to 80 ° C. After maintaining at this temperature for 5 hours, the temperature was raised to 100 ° C. and the reaction was continued for 1 hour. Thereafter, the temperature of the reaction solution was decreased to room temperature to obtain a polymer solution (solid content concentration = 30.0 wt%) containing the copolymer [A]. Mw of this copolymer was 27,000. This copolymer is referred to as copolymer (A-1).

Synthesis Example 2

In a flask equipped with a stirrer, 4 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) and 200 parts by weight of diethylene glycol ethyl methyl ether were charged, 5 parts by weight of 1,3-butadiene, 5 parts by weight of styrene, 18 parts by weight of methacrylic acid, 40 parts by weight of glycidyl methacrylate and 32 parts by weight of tricyclo [5.2.1.0 ^2,6 ] decane-8-yl methacrylate were further injected into the flask, and the inside of the flask was replaced with nitrogen. Then, these materials were gently stirred, the temperature of the reaction solution was raised to 80 ° C. and maintained at this temperature for 5 hours, and then the temperature was raised to 100 ° C. to continue the reaction for 1 hour. Thereafter, the temperature of the reaction solution was reduced to room temperature to obtain a polymer solution (solid content concentration = 29.8 wt%) containing the copolymer [A]. Mw of this copolymer was 26,000. This copolymer is referred to as copolymer (A-2).

<Example 1>

(1) Preparation of Composition Solution

As component [A], 100 weight part (solid content) of copolymer (A-1), 80 weight part of Kayarard DPHA (made by Nippon Kayaku Co., Ltd.) and 20 weights of R-1302 (made by Daiichi Kogyo Seiyaku Co., Ltd.) as component [B]. Part and 25 parts by weight of 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one (irgacure 369, manufactured by Ciba Specialty Chemicals) as component [C] Was dissolved in propylene glycol monomethyl ether acetate so as to be 35% by weight and filtered with a Millipore filter having a pore diameter of 0.2 mu m to prepare a composition solution.

(2) formation of a spacer pattern

The composition solution was applied to a glass substrate using a spinner and prebaked at 80 ° C. for 3 minutes on a hot plate to form a coating film.

Thereafter, the coating film was exposed to ultraviolet light having an intensity of 100 W / m ² at a wavelength of 365 nm for 30 seconds through a mask (10 μm × 10 μm) having a predetermined pattern in air. Thereafter, the coating film was developed with 0.2 wt% tetramethylammonium hydroxide aqueous solution at 25 ° C. for 1 minute, washed with pure water for 1 minute to remove unnecessary portions, thereby obtaining a spacer pattern (residue). This spacer pattern was cured by heating in an oven at 220 ° C. for 60 minutes to obtain a spacer pattern having a height of 5 μm.

(3) linear thermal expansion coefficient measurement

The composition solution was applied to a glass substrate using a spinner and prebaked at 80 ° C. for 3 minutes on a hot plate to form a coating film.

Thereafter, the coating film was exposed to ultraviolet light having an intensity of 100 W / m ² for 30 seconds in air at a wavelength of 365 nm, and developed for 1 minute at 25 ° C. with 0.2 wt% aqueous tetramethylammonium hydroxide solution. The coating for measurement was prepared by washing with pure water for 1 minute and curing by heating in an oven at 220 ° C. for 60 minutes.

The temperature increase rate was 2.5 ° C / min and the measurement temperature range was 20 to 180 ° C by an ellipsometer (DVA-36LH, manufactured by Mizojiri Kogaku Kogyosho Co., Ltd.) equipped with a temperature variable device. The thickness change of the film at each measurement temperature was measured, plotted against the temperature, and the slope ε was determined from the linear approximation thereof to obtain a linear thermal expansion coefficient α from the equation: α = ε / T. Here, T represents the initial film thickness.

The linear coefficient of thermal expansion of conventional spacer materials is 2.0 × 10 ⁻⁴ / ° C. or less. When the linear thermal expansion coefficient exceeds the above value, it can be said that the linear thermal expansion coefficient is high. The measurement results are shown in Table 1 below.

(4) Evaluation of spacer strength

The intensity | strength of the spacer pattern obtained by said (2) was evaluated with the micro compression tester (MCTM-200, the Shimadzu Corporation make) at the measurement temperature of 25 degreeC. Plane indenter with a diameter of 50 μm, applied to the spacer at a fixed speed (2.65 mN / sec) to break the load and fracture distortion when the spacer is cracked or broken (compression displacement at break divided by spacer height in% Measured). The evaluation results are shown in Table 1.

(5) Evaluation of heat resistance compressibility

The heat compressibility of the spacer pattern obtained in the above (2) was evaluated by a micro compression tester (MCTM-200, manufactured by Shimadzu Corporation). A planar indenter with a diameter of 50 μm was applied to the spacer heated at 160 ° C. at a fixed rate (0.28 mN / sec), and the load was removed when the spacer was compressed by 0.75 μm to obtain a recovery rate from the following equation.

Recovery Rate (%) = (0.75-Residual Distortion) × 100 / 0.75

When recovery rate is 90% or more, it can be said that heat compressibility is favorable. The evaluation results are shown in Table 1.

(6) Evaluation of heat resistant dimensional stability

The spacer pattern obtained in (2) was heated in an oven at 250 ° C. for 60 minutes to measure the dimensional change rate of the film thickness before and after heating. When the said value is 5% or less, it can be said that heat-resistant dimensional stability is favorable. The evaluation results are shown in Table 1.

<Example 2>

A composition solution was prepared and evaluated in the same manner as in Example 1, except that 70 parts by weight of Gayarad DPHA (manufactured by Nippon Kayaku Co.) and 30 parts by weight of R-1302 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were used as component [B]. It was. The evaluation results are shown in Table 1.

<Example 3>

A composition solution was prepared and evaluated in the same manner as in Example 1 except that Copolymer (A-2) was used as component [A]. The evaluation results are shown in Table 1.

Comparative Example 1

A composition solution was prepared and evaluated in the same manner as in Example 1 except that Copolymer (A-2) was used as component [A] and 100 parts by weight of Gayarad DPHA (manufactured by Nippon Kayaku Co., Ltd.) was used as component [B]. It was. The evaluation results are shown in Table 1.

As described above, according to the present invention, the gap width between the substrates can be kept constant at room temperature and high temperature, it is possible to ensure excellent display quality at all times without being affected by the temperature change, and the shape of the spacer A spacer for a display panel is provided, which is not limited and the degree of freedom in position and panel design. The radiation sensitive resin composition of this invention can form the spacer for display panels which has the said characteristic and is excellent in physical properties, such as intensity | strength, heat-compression resistance, and heat-resistant dimensional stability.

Claims (4)

A spacer for a display panel with a linear thermal expansion coefficient greater than 2.0 × 10 ⁻⁴ / ° C. and less than 8.0 × 10 ⁻⁴ / ° C. (A) a copolymer of (a1) unsaturated carboxylic acid and / or unsaturated carboxylic anhydride with (a2) unsaturated compounds other than said component (a1), [B] polyfunctional unsaturated monomers, and [C] The display panel according to claim 1, wherein the linear thermal expansion coefficient of the cured coating film of the radiation-sensitive resin composition is greater than 2.0 × 10 ⁻⁴ / ° C. and 8.0 × 10 ⁻⁴ / ° C. or less, including the radiation-sensitive polymerization initiator. A radiation sensitive resin composition used to form a spacer. 3. The polyfunctional (meth) acrylic acid ester according to claim 2, wherein the content of component [B] is 10 to 150 parts by weight based on 100 parts by weight of component [A], and component [B] is a polyfunctional (meth) acrylic acid ester having a urethane bond. A radiation-sensitive resin composition containing 10 to 50 weight% with respect to the total amount of]. The liquid crystal display element containing the spacer for display panels of Claim 1.