JP2009133971A - Photosensitive resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition for a photo-spacer having superior flexibility and elastic restoring characteristics in its curing matter by making alkali development good. <P>SOLUTION: The photosensitive resin composition contains a hydrophilic resin (A), a multi-functional (meta)acrylate monomer (B), and a radical photopolymerization-initiator (C). In the photosensitive resin composition for the photo-spacer (Q) capable of alkali development, acryloyl group concentration based on the weight of a solid part of the photosensitive resin composition is 2.0-5.5 mmol/g, and the photo-spacer formed to optically cure the photosensitive resin composition is 60% or more of an elastic restoring ratio to compression load of 1.5 Gpa. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a photosensitive resin composition for a photospacer that is cured by light irradiation and is capable of alkali development, and a photospacer provided for maintaining a gap in a liquid crystal cell formed using the composition. .

  In recent years, liquid crystal display devices have attracted attention, and photosensitive resins are frequently used in the manufacturing process. For example, the portion corresponding to the pixel on the color filter is a color pigment dispersion resist, and the resist is also used for the black matrix. As a resist used for such a part, a so-called negative resist is often used in which, when exposed through a photomask, only a part irradiated with light hardens and an unexposed part is peeled off by development.

  Now, in the liquid crystal display device technology, in order to maintain the thickness of the liquid crystal layer between both the color filter side substrate and the thin film transistor (TFT) side substrate, glass or resin transparent spherical particles (beads) called spacers are used. Sprayed inside the cell. Since these spacers are transparent particles, if there is a liquid crystal and a spacer in the pixel, light leaks through the spacer particles during black display, and both substrates in which the liquid crystal is sealed The presence of the spacer particles between them disturbs the orientation of the liquid crystal molecules in the vicinity of the spacer particles, causing light leakage at this portion, resulting in a decrease in the contrast of the liquid crystal display device and adversely affecting the display quality. Yes. Also, for example, in a liquid crystal display device in which the distance between the two substrates (the thickness of the liquid crystal layer) is narrow, such as a ferroelectric liquid crystal, the distance between the two substrates can be maintained uniformly and accurately using this spacer particle. It is difficult.

  As a technique for solving such a problem, for example, a photosensitive resin is used and a photolithography method such as partial pattern exposure and development is performed on a black matrix in a lattice pattern located at a desired position, for example, between pixels. A method of forming a columnar resin spacer has been proposed. Such a spacer is hereinafter referred to as a photo spacer. Since the photo spacer can be formed at a position avoiding the pixels, it does not adversely affect the display quality as described above, and the display quality can be improved.

  On the other hand, in recent years, a drop method (ODF method) (ODF: One Drop Fill) has been proposed in place of the conventional liquid crystal inflow method (vacuum suction method) as the mother glass for LCD (Liquid Crystal Display) manufacture becomes larger. ing. In the ODF method, after a predetermined amount of liquid crystal is dropped, the liquid crystal is injected by being sandwiched between substrates, so that the number of processes and the process time can be reduced as compared with the conventional vacuum suction method. However, in the ODF method, a predetermined amount of liquid crystal calculated from the cell gap is dropped and held, so that flexibility in correcting height variations and subtle pressure in the plane applied at that time are obtained. It is desirable for photo spacers to have elastic properties that do not affect the difference.

  That is, a photo spacer having excellent flexibility and a high elastic recovery rate is required. Photo spacers that do not have such characteristics may cause bubbles in the liquid crystal when the panel is produced, and the cell gap is not uniform, and the display quality of the liquid crystal display device deteriorates. For example, color unevenness is noticeable. Inconveniences, such as becoming something, occur. As a proposal for solving these problems, for example, a photosensitive resin composition for photospacers having an alkali developability (Patent Document 1) has been proposed. In this proposal, a photo spacer having excellent mechanical strength is proposed by using a photopolymerizable monomer, a photopolymerization initiator, and an epoxy resin having alkali developability and reactivity in combination. However, in a composition in which such an epoxy resin and a carboxylic acid component necessary for alkali development coexist, a crosslinking reaction proceeds between the epoxy group and the carboxylic acid. As a result, there is a problem that the completed photo spacer becomes brittle and the elastic recovery characteristic deteriorates.

In recent years, a further new proposal (Patent Document 2) has been made as a material for forming a photospacer having characteristics for solving the above-described problems. In this proposal, the amount of polyfunctional monomer in the total solid content is improved by 50 to 70%. However, when a large amount of polyfunctional monomer is used, there is a problem that alkali developability and adhesion to a substrate are deteriorated.
JP 2001-226449 A JP 2002-174812 A

  The present invention has been made in order to solve the above-mentioned problems, and is a photosensitive resin composition for a photospacer that has good alkali developability and has a cured product with excellent flexibility and excellent elastic recovery characteristics. Furthermore, it is an object to provide a photospacer having excellent flexibility and excellent elastic recovery characteristics.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems.
That is, the present invention is a photosensitive resin composition containing a hydrophilic resin (A), a polyfunctional (meth) acrylate monomer (B), and a radical photopolymerization initiator (C). The (meth) acryloyl group concentration based on the weight of the solid content is 2.0 mmol / g to 5.5 mmol / g, and the photo spacer formed by photocuring the photosensitive resin composition has 1.5 Gpa. Photosensitive resin composition (Q) for photo-spacer capable of alkali development having an elastic recovery rate of 60% or more with respect to a compressive load; and provided for maintaining a gap in a liquid crystal cell formed by curing the resin composition. Photo spacer.

The photosensitive resin composition of the present invention and the photospacer obtained therefrom have the following effects.
-The photosensitive resin composition is excellent in alkali developability.
-Photo spacers have excellent flexibility and elastic recovery characteristics.
-The photo spacer has excellent adhesion to the substrate.

  The photosensitive resin composition of the present invention comprises a hydrophilic resin (A) [hereinafter sometimes simply referred to as (A)], a polyfunctional (meth) acrylate monomer (B) [hereinafter simply referred to as (B). And a radical photopolymerization initiator (C) [hereinafter sometimes simply referred to as (D)], having excellent alkali developability, flexibility, and elastic recovery characteristics And a photo spacer excellent in adhesion.

  In the above and the following, for example, the expression with (meth) such as “(meth) acrylate” means “acrylate and / or methacrylate”.

  Below, (A)-(C) which is an essential structural component of the photosensitive resin composition of this invention is demonstrated in order.

The hydrophilicity index in the hydrophilic resin (A) in the present invention is defined by HLB. Generally, the larger this value, the higher the hydrophilicity.
Although the preferable range of the HLB value of (A) varies depending on the resin skeleton of (A) (for example, vinyl resin, epoxy resin, polyester resin, etc.), it is usually 4 to 19, preferably 5 to 18, and Preferably it is 6-17. When it is 4 or more, the developing property is further improved when developing the photo spacer, and when it is 19 or less, the water resistance of the cured product is further improved. In addition, HLB in this invention is an HLB value by the Oda method, is a hydrophilicity-hydrophobicity balance value, and can be calculated from the ratio of the organic value and inorganic value of an organic compound.
HLB≈10 × Inorganic / Organic In addition, the inorganic value and the organic value are described on page 501 of the document “Synthesis of Surfactant and its Application” (published by Tsuji Shoten, written by Oda, Teramura); It is described in detail on page 198 of “Introduction to New Surfactants” (Takehiko Fujimoto, published by Sanyo Chemical Industries, Ltd.).

  Moreover, the solubility parameter (hereinafter referred to as SP value) of (A) is preferably 7 to 14, more preferably 8 to 13, and particularly preferably 11 to 13. When it is 7 or more, the developability can be further improved, and when it is 14 or less, the water resistance of the cured product is further improved.

  The SP value in the present invention is calculated by the method described in the following document proposed by FEDORS et al.

“POLYMER ENGINEERING AND SCIENCE, FEBRUARY, 1974, Vol. 14, No. 2, ROBERT F. FEDORS. (Pp. 147 to 154)” Those with close SP values are likely to mix with each other (highly dispersible) It is an index showing that things that are separated are difficult to mix.

(A) preferably has a carboxyl group from the viewpoint of developability. The carboxyl group content is indicated by an acid value.
When the acid value of (A) is 10 mgKOH / g or more, developability is more likely to be exhibited, and when it is 500 mgKOH / g or less, the water resistance of the cured product can be further improved.

The acid value in the present invention can be measured by an indicator titration method using an alkaline titration solution.
The method is as follows.
(I) About 1 g of a sample is precisely weighed and placed in an Erlenmeyer flask, and then a neutral methanol / acetone solution (a mixture of acetone and methanol at 1: 1 (volume ratio)) is added and dissolved.
(Ii) Add several drops of phenolphthalein indicator and titrate with 0.1 mol / L potassium hydroxide titration solution. The end point of neutralization is defined as the time when the indicator is slightly red for 30 seconds.
(Iii) Determine using the following equation.
Acid value (KOHmg / g) = (A × f × 5.61) / S
However, A: The number of mL of 0.1 mol / L potassium hydroxide titration solution.
f: Potency of 0.1 mol / L potassium hydroxide titration solution
S: Sampling amount (g)

Examples of (A) include a hydrophilic vinyl polymer (A1) (hereinafter sometimes simply referred to as (A1)) and a hydrophilic epoxy polymer (A2) (hereinafter simply referred to as (A2)). ), Hydrophilic polyester resins, hydrophilic polyamide resins, hydrophilic polycarbonate resins, and hydrophilic polyurethane resins. (A) may be used by 1 type and may use 2 or more types together.
Among these, (A1) and (A2) are preferable from the viewpoint of photocuring reactivity of the photosensitive resin composition and the viewpoint of ease of production.

  Examples of (A1) include those having a hydrophilic group in the side chain and / or terminal of the vinyl polymer molecule. Examples of the hydrophilic group include a carboxyl group, a hydroxyl group, a sulfonic acid group, an amino group, an amide group, a polyether group, and a combination of two or more of these. In order to exhibit sufficient developability, those having a hydrophilic group, particularly a carboxyl group in the side chain are preferred.

  A preferred production method of (A1) is a vinyl monomer having a hydrophilic group (a) (hereinafter sometimes simply referred to as (a)) and, if necessary, a hydrophobic group-containing vinyl monomer (b) (hereinafter simply referred to as (b) ) Is sometimes vinyl-polymerized.

Examples of the vinyl monomer (a) having a hydrophilic group include the following vinyl monomers (a1) to (a7).
(A1) Hydroxyl-containing vinyl monomer:
Hydroxyalkyl (meth) acrylate [2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, etc.], polyalkylene glycol mono (meth) acrylate [polyethylene glycol mono (meta ) Acrylate etc.], alkylol (meth) acrylamide [N-methylol (meth) acrylamide etc.], hydroxystyrene and 2-hydroxyethylpropenyl ether.
Among (a1), preferred is hydroxyalkyl (meth) acrylate, particularly 2-hydroxyethyl (meth) acrylate, from the viewpoint of alkali developability.

(A2) Carboxyl group-containing vinyl monomer:
Unsaturated monocarboxylic acids [such as (meth) acrylic acid, crotonic acid and cinnamic acid], unsaturated polyvalent (2-4 valent) carboxylic acids [such as (anhydrous) maleic acid, itaconic acid, fumaric acid and citraconic acid], Unsaturated polyvalent carboxylic acid alkyl (alkyl group having 1 to 10 carbon atoms) ester [maleic acid monoalkyl ester, fumaric acid monoalkyl ester, citraconic acid monoalkyl ester, etc.] and salts thereof [alkali metal salt (sodium salt) And potassium salts, etc.), alkaline earth metal salts (calcium salts and magnesium salts, etc.), amine salts and ammonium salts, etc.].
Of (a2), preferred is an unsaturated monocarboxylic acid from the viewpoint of hydrophilicity, and more preferred is (meth) acrylic acid.
(A3) Sulphonic acid group-containing vinyl monomer:
Examples thereof include vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, α-methyl styrene sulfonic acid, 2- (meth) acryloylamido-2-methylpropane sulfonic acid, and salts thereof. Examples of the salt include alkali metal (sodium and potassium) salts, alkaline earth metal (calcium and magnesium) salts, primary to tertiary amine salts, ammonium salts and quaternary ammonium salts.

(A4) Amino group-containing vinyl monomer:
Tertiary amino group-containing (meth) acrylates [dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate)] and the like.
(A5) Amide group-containing vinyl monomer:
(Meth) acrylamide, N-alkyl (C1-6) (meth) acrylamide, diacetone acrylamide, N, N'-methylene-bis (meth) acrylamide, N, N-dialkyl (C1-6) or Diaralkyl (7 to 15 carbon atoms) (meth) acrylamide (for example, N, N-dimethylacrylamide and N, N-dibenzylacrylamide), methacrylformamide, N-methyl-N-vinylacetamide, cinnamic amide and cyclic amide (N-vinylpyrrolidone, N-allylpyrrolidone, etc.).
(A6) a quaternary ammonium base-containing vinyl monomer;
A quaternized product of a tertiary amino group-containing vinyl monomer having 6 to 50 carbon atoms (preferably 8 to 20 carbon atoms, such as methyl chloride, dimethyl sulfate, benzyl chloride and dimethyl carbonate), for example, dimethyl Examples include quaternized products of aminoethyl (meth) acrylate, quaternized products of diethylaminoethyl (meth) acrylate, quaternized products of dimethylaminoethyl (meth) acrylamide, and quaternized products of diethylaminoethyl (meth) acrylamide.
(A7) Polyether group-containing vinyl monomer:
Alkoxy (alkoxy group having 1 to 8 carbon atoms) polyalkylene (alkylene group having 2 to 4 carbon atoms) glycol mono (meth) acrylate [methoxypolyethylene glycol (degree of polymerization 2 to 40) mono (meth) acrylate and methoxypolypropylene glycol ( Polymerization degree 2-30) mono (meth) acrylate, etc.].

  Of these, (a) is preferably (a1) and (a2), particularly (a2) from the viewpoint of imparting sufficient developability.

  Examples of the hydrophobic group-containing vinyl monomer (b) include the following nonionic monomers (b1) to (b6).

(B1) (meth) acrylic acid ester;
C1-C20 alkyl (meth) acrylate of an alkyl group [for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, n-hexyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, etc.]; alicyclic group-containing (meth) acrylate [dicyclopentanyl (meth) acrylate, sidiclopentenyl (meth) acrylate, isobornyl (meth) acrylate, etc. ];

(B2) an aromatic hydrocarbon monomer;
And hydrocarbon monomers having a styrene skeleton [for example, styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethylstyrene, isopropylstyrene, butylstyrene, phenylstyrene, cyclohexylstyrene, and benzylstyrene] and vinylnaphthalene. It is done.
(B3) carboxylic acid vinyl ester;
Examples thereof include those having 4 to 50 carbon atoms, such as vinyl acetate, vinyl propionate and vinyl butyrate.
(B4) vinyl ether monomers;
Those having 3 to 50 (preferably 6 to 20) carbon atoms such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, vinyl butyl ether and the like can be mentioned.
(B5) vinyl ketone monomer;
Examples thereof include those having 4 to 50 carbon atoms, such as vinyl methyl ketone, vinyl ethyl ketone, and vinyl phenyl ketone.
(B6) a halogen atom-containing monomer;
Examples thereof include those having 2 to 50 (preferably 2 to 20) carbon atoms, such as vinyl chloride, vinyl bromide, vinylidene chloride, chlorostyrene and bromostyrene.

  Among (b), (b1) is preferable from the viewpoint of photocuring reactivity, and alicyclic group-containing (meth) acrylate is more preferable.

  In (A1), the charged monomer molar ratio of (a) / (b) is usually 10 to 100/0 to 90, preferably 10 to 80/20 to 90, more preferably from the viewpoint of photocuring reactivity and developability. Is 25-85 / 15-75.

(A1) may contain a (meth) acryloyl group in the side chain for the purpose of further improving photocuring reactivity in the polymer having (a) and, if necessary, (b) as a constituent monomer. Good.
Examples of the method of incorporating a (meth) acryloyl group in the side chain include the following methods (1) and (2).
(1): A polymer is produced using a monomer having a group capable of reacting with an isocyanate group (such as a hydroxyl group or a primary or secondary amino group) in at least a part of (a), and then (meth) A method of reacting a compound having an acryloyl group and an isocyanate group (such as acryloylethyl isocyanate);
(2); producing a polymer using a monomer having a group capable of reacting with an epoxy group (hydroxyl group, carboxyl group, primary or secondary amino group, etc.) in at least a part of (a); A method of reacting a compound having a (meth) acryloyl group and an epoxy group (such as glycidyl acrylate).

  The number average molecular weight of (A1) (hereinafter abbreviated as Mn. The measured value by gel permeation chromatography) is preferably 500 to 500, from the viewpoint of photocuring reactivity and developability as the photosensitive resin composition. 000, more preferably 1,000 to 100,000, and particularly preferably 3,000 to 20,000.

  (A1) can be obtained by performing polymerization with a radical polymerization initiator after diluting the monomer with a solvent (D5) (hereinafter sometimes simply referred to as (D5)) if necessary. Examples of the solvent (D5) include glycol ethers (such as ethylene glycol monoalkyl ether and propylene glycol monoalkyl ether), ketones (such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone), and esters (butyl acetate, ethylene glycol alkyl). Ether acetate and propylene glycol alkyl ether acetate). Of these (D5), ketones and esters are preferred.

  When (D5) is used, the amount used is not particularly limited, but is usually 1 to 400% based on the total weight of the monomers (in the following, unless otherwise specified,% represents% by weight), preferably 5 to 5%. 300%, particularly preferably 10 to 200%.

  Examples of the polymerization initiator include peroxides and azo compounds. Peroxides include inorganic peroxides (eg, hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, etc.) and organic peroxides (eg, benzoyl peroxide, di-t-butyl peroxide, Cumene hydroperoxide, lauryl peroxide, etc.). Examples of the azo compound include azobis (2,4-dimethylvaleronitrile), azobisisobutyronitrile, azobis (2-methylbutyronitrile), azobiscyanovaleric acid and its salts (for example, hydrochloride), and azobis (2 -Amidinopropane) hydrochloride and the like. Preferred is an azo compound. As a usage-amount of a polymerization initiator, 0.0001-20% is preferable normally based on the total weight of a monomer, More preferably, it is 0.001-15%, Most preferably, it is 0.005-10%. The reaction temperature and reaction time are appropriately determined depending on the type of radical polymerization initiator.

  As described above, the hydrophilicity index of (A) is defined by HLB. Of these, the HLB value of (A1) is preferably 9 to 19, more preferably 10 to 18, particularly preferably 11 to 17. It is. If the HLB of (A1) is 9 or more, developability can be further improved.

The epoxy-based polymer (A2) in the present invention (A) (hereinafter sometimes simply referred to as (A2)) has an epoxy resin skeleton containing a functional group having hydrophilicity such as a hydroxyl group or a carboxyl group. It is a polymer.
(A2) preferably has a (meth) acryloyl group in the molecule from the viewpoint of photocuring reactivity.

A preferred production method of (A2) is an epoxy resin obtained by reacting a (meth) acryloyl group-containing monocarboxylic acid with an epoxy group in an epoxy resin (A2 ₀ ) (hereinafter sometimes simply referred to as (A2 ₀ )). A method of reacting a part of the hydroxyl group with a polyvalent carboxylic acid or a polyvalent carboxylic acid anhydride (e) (hereinafter sometimes simply referred to as (e)). is there.

Examples of (A2 ₀ ) include aliphatic epoxy resins [eg, Etototo YH-300, PG-202, PG-207 (all manufactured by Tohto Kasei Co., Ltd.)] and alicyclic epoxy resins [eg, CY-179, CY-177. CY-175 (all manufactured by Asahi Kasei Epoxy Co., Ltd.)] and aromatic epoxy resins [eg, phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol A epoxy resin, biphenyl type epoxy resin and glycidyl modified polyvinylphenol] Can be mentioned. Among (A2 ₀ ), an aromatic epoxy resin is preferable from the viewpoint of curability.

  Examples of the (meth) acryloyl group-containing monocarboxylic acid used for the production of (A2) include acrylic acid and methacrylic acid.

  Examples of the polyvalent carboxylic acid and polyvalent carboxylic acid anhydride (e) used in the production of (A2) include the unsaturated polyvalent carboxylic acids and anhydrides of the above-mentioned (a), and saturated polyvalent carboxylic acids. (2-6 valent) carboxylic acids (eg, aliphatic saturated polyvalent carboxylic acids such as oxalic acid, succinic acid, phthalic acid, adipic acid, dodecanedioic acid, dodecenyl succinic acid, pentadecenyl succinic acid and octadecenyl succinic acid) Acids; aromatic polycarboxylic acids such as tetrahydrophthalic acid, hexahydrophthalic acid, methyltetrahydrophthalic acid, trimellitic acid, pyromellitic acid, biphenyltetracarboxylic acid and naphthalenetetracarboxylic acid) and their anhydrides (for example, Succinic anhydride, dodecenyl succinic anhydride, pentadecenyl succinic anhydride, octadecenyl succinic anhydride, etc. Aliphatic saturated polycarboxylic anhydrides; phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, biphenyltetracarboxylic anhydride and naphthalenetetracarboxylic Aromatic polyhydric carboxylic acid anhydrides such as acid anhydrides). A saturated polycarboxylic acid anhydride is preferable from the viewpoint of reactivity and developability.

In the production of (A2), the charged weight ratio of (meth) acrylic acid / (A2 ₀ ) is preferably such that the concentration of the (meth) acryloyl group in (A2) is 1.0 mmol / g or more (meta ) Acrylic acid charge weight ratio. From the above viewpoint, the weight ratio of acrylic acid / (A2 ₀ ) is preferably 0.072 or more / 1, and more preferably 0.079 to 0.72 / 1. The weight ratio of methacrylic acid is preferably 0.092 or more / 1, more preferably 0.10 to 0.92 / 1, from the above viewpoint.

The reaction temperature in the reaction between (A2 ₀ ) and (meth) acrylic acid is not particularly limited, but is preferably 70 to 110 ° C. The reaction time is not particularly limited, but is preferably 5 to 30 hours. Further, if necessary, a catalyst (for example, triphenylphosphine) and a radical polymerization inhibitor (hydroquinone, p-methoxyphenol, etc.) may be used.
The charged equivalent of the polyvalent carboxylic acid or polyvalent carboxylic acid anhydride (e) with respect to the weight of the (meth) acrylic acid adduct of (A2 ₀ ) is such that the acid value of (A2) is preferably 10 to 500 mgKOH. For example, when (e) is a divalent carboxylic acid or its anhydride, (e) is equivalent to (e) charged equivalent / (A2 ₀ ) (meth) acrylic acid From the above viewpoint, the weight of the adduct is preferably 0.18 to 8.9 meq / g, and more preferably 0.53 to 7.1 meq / g.

The reaction temperature in the reaction of the (A2 ₀ ) (meth) acrylic acid adduct and (e) is not particularly limited, but is preferably 70 to 110 ° C. The reaction time is not particularly limited, but is preferably 3 to 10 hours.

  Mn of (A2) is usually 500 to 3,000, preferably 1,000 to 2,800, particularly preferably 1,500 to 2, from the viewpoint of photocuring reactivity and developability as the photosensitive resin composition. , 500.

  The HLB value of (A2) is preferably 4 to 14, more preferably 5 to 13, and particularly preferably 6 to 12. If the HLB of (A2) is 4 or more, the developability can be satisfactorily exhibited.

  In the present invention, the polyfunctional (meth) acrylate monomer (B) (hereinafter sometimes simply referred to as (B)) used as one component in the photosensitive resin composition is a known polyfunctional (meta) The acrylate monomer is not particularly limited, and examples thereof include bifunctional (meth) acrylate (B1), trifunctional (meth) acrylate (B2), and 4-6 functional (meth) acrylate (B3).

  Examples of the bifunctional (meth) acrylate (B1) include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, and polyethylene glycol di (meth). Acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerin di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate ( SP value of methacrylate = 12.5, SP value of acrylate = 10.3), 1,9-nonanediol di (meth) acrylate, 1,10-decandiol di (meth) acrylate, 3-methyl-1, -Pentanediol di (meth) acrylate, 2-butyl-2-ethyl-1,3-propanediol di (meth) acrylate, dimethylol-tricyclodecane di (meth) acrylate, di (ethylene oxide adduct of bisphenol A ( Examples include (meth) acrylate, di (meth) acrylate of propylene oxide adduct of bisphenol A, and neopentyl glycol di (meth) acrylate of hydroxypivalate.

  As trifunctional (meth) acrylate (B2), glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tri (meth) acrylate of trimethylolpropane ethylene oxide adduct Etc. are exemplified.

  Examples of the 4-6 functional (meth) acrylate (B3) include pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the like.

  Among (B), preferred are (B2) and (B3), and more preferred is a polymer containing a hydroxyl group from the viewpoint of compatibility with (C) described later, and particularly preferred is dipentaerythritol pentaacrylate, Pentaerythritol triacrylate and combinations thereof. As (B) which can be easily obtained from the market, for example, Aronix M-403 (manufactured by Toagosei Co., Ltd.), light acrylate PE-3A (manufactured by Kyoeisha Chemical Co., Ltd.), neomer DA-600 (Sanyo Chemical Industries ( Etc.).

Moreover, (B) in this invention may contain the photosensitive acrylic oligomer (B4) in the one part. Examples of (B4) include urethane acrylate, polyester acrylate, and polyether acrylate having Mn of 1,000 or less and containing no carboxyl group and having two or more acryloyl groups in one molecule.
The content of (B4) in (B) is preferably 50% or less, more preferably 30% or less.

  Examples of the photo radical polymerization initiator (C) used as one component in the photosensitive resin composition (Q) include benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, and 2-hydroxy-2-methyl-1-phenyl. Propan-1-one, benzophenone, methylbenzoyl formate, isopropylthioxanthone, 4,4-bis (dimethylamino) benzophenone, 3,3-dimethyl-4-methoxy-benzophenone, anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone , Tert-butylanthraquinone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy Cetophenone, 2-hydroxy-2-methylpropiophenone, 4-isopropyl-2-hydroxy-2-methylpropiophenone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone 2-chlorothioxanthone, diethylthioxanthone, isopropylthioxanthone, diisopropylthioxanthone, Michler's ketone, benzyl-2,4,6- (trihalomethyl) triazine, 2- (o-chlorophenyl) -4,5-diphenylimidazolyl dimer, 9 -Phenylacridine, 1,7-bis (9-acridinyl) heptane, 1,5-bis (9-acridinyl) pentane, 1,3-bis (9-acridinyl) propane, dimethylbenzyl ketal, trimethylbenzoyldiphenylphosphine Sid, tribromomethylphenylsulfone and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) - butan-1-one, and the like. (C) may be used alone or in combination of two or more.

  (C) can be easily obtained as a commercially available product. For example, as 2-methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone, Irgacure 907, 2-benzyl- Examples of 2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one include Irgacure 369 (manufactured by Ciba Specialty Chemicals).

  The photosensitive resin composition (Q) of the present invention contains (A), (B) and (C) in the following amounts based on the weight of the total solid content of (Q). In the present invention, “solid content” refers to components other than the solvent.

(A) is usually 40% to 89% by weight (in the following, unless otherwise specified,% represents% by weight), preferably 45 to 84%, more preferably 50 to 75%.
If it is 40% or more, the adhesiveness can be exhibited more favorably, and if it is 90% or less, the elastic recovery property of the cured product is further improved.

  (B) is usually 10% to 59%, preferably 15 to 54%, more preferably 20 to 49%. If it is 10% or more, the elastic recovery property of the cured product is further preferable, and if it is 59% or less, the adhesion is further improved.

  (C) is usually 0.01 to 10%, preferably 0.05 to 7%, more preferably 0.1 to 5%. If it is 0.01% or more, the photocuring reactivity can be exhibited more satisfactorily, and if it is 10% or less, the resolution can be further improved.

  In the photosensitive resin composition (Q), the content of (C) with respect to the total weight of (A) when it has (B) and (meth) acryloyl groups is 0.02 to 10% from the viewpoint of curability. It is preferable that it is 0.05 to 7%.

The photosensitive resin composition (Q) may further contain other components (D) as necessary.
As (D), polysiloxane (D1) having a hydrolyzable alkoxy group, inorganic fine particles (D2), sensitizer (D3), polymerization inhibitor (D4), solvent (D5), acid generator (D6) And other additives (D7) (for example, inorganic pigments, silane coupling agents, dyes, fluorescent brighteners, yellowing inhibitors, antioxidants, antifoaming agents, deodorants, fragrances, bactericides, Antibacterial agents and fungicides, etc.).

  The polysiloxane (D1) having a hydrolyzable alkoxy group has the silane compound (d1) represented by the general formula (1) as an essential constituent monomer, and the alkoxy group [OR3 in the general formula (1)] It is a condensate partly polymerized by condensation reaction.

In the formula, R ¹ is one or more organic groups selected from the group consisting of a (meth) acryloyloxyalkyl group, a glycidoxyalkyl group, a mercaptoalkyl group, and an aminoalkyl group, and R ² has 1 to 12 carbon atoms. An aliphatic saturated hydrocarbon group or an aromatic hydrocarbon group having 6 to 12 carbon atoms, R ³ is an alkyl group having 1 to 4 carbon atoms, and m is 0 or 1.

R ¹ does not react in the condensation reaction step (d1) but remains in the polysiloxane (D1) after the condensation reaction, and contributes to the thermosetting reaction when the photosensitive resin composition of the present invention is thermoset. It is a functional group.
R ¹ is preferably a (meth) acryloyloxyalkyl group or a glycidoxyalkyl group from the viewpoint of curability.

Among R ² , examples of the aliphatic saturated hydrocarbon group include a linear alkyl group, a branched alkyl group, and an alicyclic saturated hydrocarbon group. Examples of linear alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-octyl and n-dodecyl groups and their deuterium substitutes, and examples of branched alkyl groups include isopropyl, isobutyl, sec-butyl and 2- Examples of the ethylhexyl group and the cyclic saturated hydrocarbon group include a cyclohexyl group, a cyclooctyl group, a cyclohexylmethyl group, a cyclohexylethyl group, and a methylcyclohexyl group. Examples of the aromatic hydrocarbon group include an aryl group, an aralkyl group, and an alkylaryl group.

  As aryl groups, phenyl, biphenyl, naphthyl groups and their deuterium, fluorine or chlorine substituents; As aralkyl groups, tolyl, xylyl, mesityl and their deuterium, fluorine or chloride; and as alkylaryl groups Examples include methylphenyl and ethylphenyl groups.

R ² is preferably a linear alkyl group, branched alkyl group and aryl group from the viewpoint of curing reactivity, more preferably a linear alkyl group and aryl group, particularly preferably a methyl group, an ethyl group, a phenyl group and These are combined.
Examples of R ³ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and a sec-butyl group, and a methyl group and an ethyl group are preferable from the viewpoint of thermosetting reactivity. .

In the general formula (1), examples of the silane compound having a (meth) acryloyloxyalkyl group as R ¹ include the following compounds.
m is 0, that is, a trifunctional silane compound having three alkoxy groups; 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltrimethoxysilane, and 3-acryloyl Roxypropyltriethoxysilane etc.
m is 1, that is, a trifunctional silane compound having two alkoxy groups; 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane and 3-acryloyl Leuoxypropylmethyldiethoxysilane and the like.

Examples of the silane compound having a glycidoxyalkyl group as R ¹ include the following compounds.

m is 0, that is, a trifunctional silane compound having three alkoxy groups; 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and the like.
m is 1, that is, a trifunctional silane compound having two alkoxy groups; 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and the like.

Examples of the silane compound having a mercaptoalkyl group as R1 include the following compounds.
m is 0, that is, a trifunctional silane compound having three alkoxy groups; 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and the like m is 1, that is, a trifunctional silane compound having two alkoxy groups; Mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, etc.

Examples of the silane compound having an aminoalkyl group as R ¹ include the following compounds.
m is 0, that is, a trifunctional silane compound having three alkoxy groups; N-2 aminoethyl γ-aminopropyltrimethoxysilane, N-2 aminoethyl γ-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, And 3-aminopropyltriethoxysilane and the like, wherein m is 1, that is, a trifunctional silane compound having two alkoxy groups; N-2 aminoethyl γ-aminopropylmethyldimethoxysilane, N-2 aminoethyl γ-aminopropylmethyldiethoxy Silane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, etc.

Of (d1), from the viewpoint of curing reactivity, R ¹ in the general formula (1) is preferably a silane compound having a (meth) acryloyloxyalkyl group or a glycidoxyalkyl group, and more preferably A (meth) acryloyloxyalkyl group-containing trifunctional silane compound having three alkoxy groups, and a glycidoxyalkyl group-containing trifunctional silane compound having three alkoxy groups, and particularly preferred is 3-acryloyl Roxypropyltrimethoxysilane and 3-glycidoxypropyltrimethoxysilane.

Examples of (C) include a homocondensation polymer composed only of the silane compound (d1) and a cocondensate of one or more other silane compounds (d2) capable of cocondensing with (d1) and (d1). .
Examples of the other silane compound (d2) include a silane compound represented by the general formula (2).
R ⁴ _n Si (OR ⁵ ) _4-n (2)
In the formula, R ⁴ is an aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, R ⁵ is an alkyl group having 1 to 4 carbon atoms, and n is 0 It is an integer of ~ 2.

Examples of R ⁴ and R ⁵ include those exemplified above.
Of R ^4, a linear alkyl group, a branched alkyl group, and an aryl group are preferable, a linear alkyl group and an aryl group are more preferable, and a methyl group, an ethyl group, a phenyl group, and a combination thereof are particularly preferable.
R ⁵ is preferably a methyl group or an ethyl group.

In the general formula (2), examples of the tetrafunctional silane compound in which n is 0, that is, four alkoxy groups include tetramethoxysilane and tetraethoxysilane.
Examples of the trifunctional silane compound in which n is 1, that is, three alkoxy groups include phenyltrimethoxysilane, phenyltriethoxysilane, methyltrimethoxysilane, and methyltriethoxysilane.

  Examples of the bifunctional silane compound in which n is 2, that is, two alkoxy groups include diphenyldimethoxysilane, diphenyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldimethoxysilane, and phenylmethyldiethoxysilane. . Of these, n is preferably 1, that is, a trifunctional silane compound, from the viewpoint of forming a uniform network of polysiloxane (D1).

  The charging ratio of the other silane compound (d2) is preferably from the viewpoint of curing reactivity, and the total amount of the other silane compound (d2) is preferably 0.1 to 6.0 mol, more preferably 1 mol of (d1). 0.2 to 4.0 moles is good.

  The polysiloxane (D1) is, for example, 20 to 100 ° C. with stirring a predetermined amount of water and, if necessary, the catalyst in the silane compound (d1) and other silane compound (d2) to be used if necessary in a dry atmosphere. In about 10 minutes to 60 minutes, and then aged for 1 to 12 hours at a temperature below the boiling point of the by-produced alcohol (for example, 0 to 150 ° C.) to obtain a condensation reaction.

  When the amount of water added in the condensation reaction is X mol and the number of moles of alkoxy groups in the silane compound (d1) and the other silane compound (d2) is Y, if X / Y is too small, the yield of the condensate The molecular weight decreases. On the other hand, when X / Y is too large, the molecular weight becomes too large and the storage stability tends to decrease. From this, it is preferable to carry out in the range of 0.1 <X / Y <5, preferably in the range of 0.3 <X / Y <3. As the water to be added, ion exchange water or distilled water is usually used. Moreover, the silane compound which has one alkoxy group can also be added for the purpose of molecular weight adjustment. Examples of the silane compound having one alkoxy group include phenyltrimethoxysilane and methyltrimethoxysilane.

  Condensation reaction catalysts include formic acid, acetic acid, succinic acid, lactic acid, malonic acid, citric acid, tartaric acid, malic acid, succinic acid, fumaric acid, phthalic acid, pyromellitic acid, p-toluenesulfonic acid, methanesulfonic acid, trifluoro Monovalent, divalent or trivalent organic acids such as acetic acid and trifluoromethanesulfonic acid; inorganic acids such as hydrochloric acid, phosphoric acid, nitric acid, hydrofluoric acid, bromic acid, chloric acid and perchloric acid; alkali metal hydroxides; Alkaline earth hydroxides, quaternary alkylammonium hydroxides and carbonates and alkali salts such as primary to tertiary amines; quaternary alkylammonium halides; sodium hypochlorite; tin, zirconium, titanium , Alkoxides of metals other than silicon such as aluminum and boron, and their chelate complexes; Organic acid among this, an inorganic acid, a metal alkoxide, an acid catalyst is preferable, chelate compounds of a metal alkoxide, an organic acid is particularly preferred.

  The addition amount of the catalyst is 0.0001 to 10 parts by weight, preferably 0.001 to 1 part by weight with respect to the total of 100 parts by weight of (d1) and (d2). The method for adding the catalyst is not particularly limited, but it is preferably added as an aqueous solution. Moreover, preferable reaction temperature is 20 to 100 degreeC.

(D1) is preferably a difference in SP value from the polyfunctional (meth) acrylate monomer (B) of -2.0 to 2.0, more preferably-from the viewpoint of compatibility and elastic recovery properties of the cured product. It is 1.0 to 1.8, particularly preferably −0.5 to 1.6, and most preferably 0 to 1.4.
The SP value of (D1) is preferably 7 to 13, more preferably 8 to 12, especially from the viewpoint that the difference from the SP value of (B) described above is easily set to -2.0 to 2.0. 8-11, especially 8-10.5.

  Mn of (D1) is preferably from 500 to 100,000, more preferably from 1,000 to 50,000, particularly preferably from 2,000 to 100,000, from the viewpoint of flexibility and elastic recovery characteristics when it becomes a photospacer. 20,000.

  Based on the weight of the solid content of the photosensitive resin composition (Q), the content of (D1) is usually 0 to 40%, preferably 0 to 30%, particularly preferably 0 to 20%. If it is 40% or less, the compatibility can be further improved, and if it is 0 to 40%, the elastic recovery property of the cured product is particularly excellent.

  As the inorganic fine particles (D2), metal oxides and metal salts can be used. Examples of the metal oxide include titanium oxide, silicon oxide, and aluminum oxide. Examples of the metal salt include calcium carbonate and barium sulfate. Of these, metal oxides are preferable from the viewpoint of heat-resistant transparency and chemical resistance, and silicon oxide and titanium oxide, and particularly silicon oxide are more preferable. The inorganic fine particles have a volume average primary particle diameter of 1 to 200 nm, preferably from 1 to 150 nm, more preferably from 1 to 120 nm, and particularly preferably from 5 to 20 nm, from the viewpoint of transparency.

  The content of (D2) in the weight of the solid content of the photosensitive resin composition (Q) is usually 0 to 50%, preferably 0 to 45%, particularly preferably 0 to 40%. If it is 50% or less, the developability can be further improved, and if it is 0 to 40%, the voltage holding property of the cured product is particularly excellent.

  As the sensitizer (D3), nitro compounds (for example, anthraquinone, 1,2-naphthoquinone, 1,4-naphthoquinone, benzanthrone, p, p'-tetramethyldiaminobenzophenone, carbonyl compounds such as chloranil, nitrobenzene, p -Dinitrobenzene and 2-nitrofluorene etc.), aromatic hydrocarbons (eg anthracene and chrysene etc.), sulfur compounds (eg diphenyl disulfide etc.) and nitrogen compounds (eg nitroaniline, 2-chloro-4-nitroaniline) , 5-nitro-2-aminotoluene, tetracyanoethylene and the like.

  The content of the sensitizer (D3) based on the weight of the radical photopolymerization initiator (C) is usually 0 to 100%, preferably 0 to 80%, particularly preferably 0 to 70%.

  There is no limitation in particular as a polymerization inhibitor (D4), What is used for normal reaction is used. Specifically, diphenylhydrazyl, tri-p-nitrophenylmethyl, N- (3-N-oxyanilino-1,3-dimethylbutylidene) aniline oxide, p-benzoquinone, p-tert-butylcatechol, nitrobenzene, Examples include picric acid, dithiobenzoyl disulfide, and copper (II) chloride.

  The content of the polymerization inhibitor (D4) in the weight of the solid content of the photosensitive resin composition (Q) is preferably 0 to 1.0%, more preferably 0 to 0.5%, particularly preferably 0. ~ 0.1%.

  Examples of the solvent (D5) include those exemplified above. When the solvent is used, the amount of the solvent is not particularly limited, but is preferably 30 to 90%, more preferably 30 to 80%, of the weight of the photosensitive resin composition (Q) including the solvent. . In addition, the solvent used for manufacture of above-mentioned (A) and (B) is also contained in the compounding quantity of a solvent.

The acid generator (D6) is a compound that generates an acid by light or heat, and is added to accelerate the light or thermosetting reaction.
(D6) includes the following (i) sulfone compounds, (ii) sulfonic acid ester compounds, (iii) sulfonimide compounds, (iv) disulfonyldiazomethane (v) disulfonylmethane, and (vi) onium salts. .
(I) Sulfone compounds Phenacylphenylsulfone, 4-trisphenacylsulfone-ketosulfone, β-sulfonylsulfone, and α-diazo compounds thereof (ii) Sulfonic acid ester compounds Benzoin tosylate, pyrogallol tris-trifluoromethanesulfonate, pyrogallolmethane (Iii) sulfonimide compounds N- (trifluoromethylsulfonyloxy) succinimide, N- (p-toluenesulfonyloxy) bicyclo [2.2] sulfonic acid triester, α-methylolbenzointosylate, α-methylolbenzoindodecylsulfonate, etc. .1] Hept-5-ene-2,3-dicarboximide, N- (perfluorooctanesulfonyloxy) naphthylimide, N- (benzenesulfonyloxy) bishi [2.2.1] Hept-5-ene-2,3-dicarboximide, N- (benzenesulfonyloxy) bicyclo [2.2.1] heptane-5,6-oxy-2,3-di Carboximide and N- (benzenesulfonyloxy) naphthylimide, etc. (iv) Disulfonyldiazomethane compounds Bis (trifluoromethylsulfonyl) diazomethane, bis (phenylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (2,4 -Dimethylbenzenesulfonyl) diazomethane, bis (1-methylethylsulfonyl) diazomethane and bis (1,4-dioxaspiro [4,5] decane-7-sulfonyl) diazomethane, etc. (vi) onium salts sulfonium salts [bis [4- ( Diphenylsulfonio) phenyl] sulfi Bis hexafluorophosphate, allyl sulfonium hexafluorophosphate salts],
Iodonium salts (such as diphenyliodonium hexafluorophosphate), phosphonium salts (such as ethyltriphenylphosphonium tetrafluoroborate), diazonium salts (such as phenyldiazonium hexafluorophosphate), ammonium salts (1-benzyl-2-cyanopyridinium hexafluorophosphate, etc.) ), And ferrocene [(2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -Fe (II) hexafluorophosphate, etc.), etc.

  Of (D6), preferred are a sulfonimide compound and a disulfonyldiazomethane compound, and more preferred are N- (trifluoromethylsulfonyloxy) succinimide and bis (phenylsulfonyl) diazomethane.

  The content of (D6) in the weight of the solid content of the photosensitive resin composition (Q) is preferably 10% or less, more preferably 0 to 7%, and particularly preferably 0 to 5%. If it is 10% or less, the developability can be further improved.

The total content of components other than the solvent (D5) in (D) is usually 80% or less, preferably 70% or less, of the solid content of the photosensitive resin composition (Q).

The photosensitive resin composition (Q) of the present invention can be obtained, for example, by mixing the above-described components with a known mixing device such as a planetary mixer.
The photosensitive resin composition is usually liquid at room temperature, and its viscosity is 0.1 to 10,000 mPa · s, preferably 1 to 8,000 mPa · s at 25 ° C.

  Since the photosensitive resin composition (Q) of the present invention is excellent in the elastic recovery characteristics of the cured product, it is particularly suitable as a photosensitive resin composition for a photospacer provided for maintaining a gap in a liquid crystal cell. Yes.

The photo spacer of the present invention will be described below.
The photospacer of the present invention is a photospacer provided for maintaining a gap in a liquid crystal cell formed by curing the photosensitive resin composition (Q).
The photo spacer determines the gap of the liquid crystal cell when the color filter substrate and the TFT substrate are bonded together, and plays an important role for display quality. The photo spacer has a constant height in the range of about 2 to 5 μm, and its uniformity is required. In addition to the height, the shape, size, density, and the like required for the photo spacer are appropriately determined depending on the design of the liquid crystal display device.

Description will be made based on a method of forming a photo spacer by a photolithography method using the photosensitive resin composition (Q) of the present invention.
(Q) of this invention is uniformly apply | coated by a well-known method, such as a roll coat, a spin coat, a spray coat, a slit coat, on a board | substrate, It is made to dry and the photosensitive resin composition layer is formed. As the coating apparatus, a known coating apparatus can be used, and examples thereof include a spin coater, an air knife coater, a roll coater, a bar coater, a curtain coater, a gravure coater, and a comma coater.

Here, an example of forming on a transparent common electrode further provided on the colored layer will be described.
The photosensitive resin composition layer is dried by applying heat as necessary (pre-baking).
The drying temperature is preferably 10 ° C or higher, more preferably 12 ° C or higher, particularly preferably 15 ° C or higher, most preferably 20 ° C or higher, and preferably lower than 100 ° C, more preferably 90 ° C or lower, particularly preferably. Is 60 ° C. or lower, most preferably 50 ° C. or lower. The drying time is preferably 30 seconds or more, more preferably 1 minute or more, particularly preferably 2 minutes or more, and preferably 10 minutes or less, more preferably 8 minutes or less, particularly preferably 5 minutes or less. Drying may be performed under reduced pressure or normal pressure, but reduced pressure is preferred. Moreover, although it may carry out in air or in an inert gas, it is preferably in an inert gas.

Next, the photosensitive resin composition layer is exposed with actinic rays through a predetermined photomask. In the case of the photosensitive resin composition of the present invention, even a mask opening having a diameter of about 5 to 10 μm (area of about 20 to 100 μm ² ) is accurate, that is, a range of 6 to 12 μm in diameter (area of 30 to 120 μm ² ). Can form a pattern.

Examples of light used for exposure include visible light, ultraviolet light, and laser light. Examples of the light source include sunlight, a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, and a semiconductor laser. Although it does not specifically limit as an exposure amount, Preferably it is 20-300 mJ / cm < ² >.

Subsequently, the unexposed portion is removed with a developer, and development is performed.
Here, as the developer used for development, an alkaline aqueous solution is usually used. Examples of the alkaline aqueous solution that can be used as the developer include aqueous solutions of inorganic substances such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and sodium bicarbonate; aqueous solutions of organic substances such as hydroxytetramethylammonium and hydroxytetraethylammonium. Is mentioned. These can be used alone or in combination of two or more kinds, and a surfactant such as an anionic surfactant, a cationic surfactant, an amphoteric surfactant and a nonionic surfactant can be added and used.
As a developing method, there are a dip method and a shower method, but the shower method is preferable. The temperature of the developer is preferably 25 to 40 ° C. The development time is appropriately determined according to the film thickness and the solubility of the photosensitive resin composition.

In order to make the curing more reliable, heating (baking) may be performed as necessary.
When baking is performed, the baking temperature is preferably 100 to 250 ° C, more preferably 150 to 240 ° C, and particularly preferably 180 to 230 ° C. The baking time is 5 minutes to 6 hours, preferably 15 minutes to 4 hours, particularly preferably 30 minutes to 3 hours.
The baking may be performed under reduced pressure or normal pressure, but reduced pressure is preferred. Moreover, although it may carry out in air or in an inert gas, it is preferably in an inert gas.

  The photospacer of the present invention obtained as described above is a photospacer excellent in flexibility and elastic recovery characteristics. The flexibility of the photo spacer can be evaluated by “total deformation amount” and “elastic recovery characteristics” when a delicate pressure is applied. A larger total deformation amount and a larger elastic recovery characteristic are more flexible. The elastic recovery characteristic of the photospacer can be evaluated by “total deformation amount” and “plastic deformation amount” when pressure is applied. The larger the total deformation amount and the smaller the plastic deformation amount, the better the elastic recovery characteristics.

In the present invention, the flexibility and elastic recovery characteristics can be evaluated by measuring the following “total deformation amount, elastic recovery rate in a pressure range of 0.2 to 0.8 mN / μm ² ”.

Measuring method of “total deformation (μm)” and “elastic recovery rate (%)”;
At 25 ° C., a predetermined pressure is applied at a constant speed, held for one second, and then the total deformation amount T ₀ (from the hysteresis curve (FIG. 1) between the load and the deformation amount when the pressure is unloaded at a constant speed. μm) is obtained, and the plastic deformation amount T ₁ (μm) is obtained, and the elastic recovery rate (%) at a predetermined pressure is calculated by the following equation.
Elastic recovery rate (%) = [(T ₀ −T ₁ ) / T ₀ ] × 100
The ^{pressure, 0.2mN / μm 2, 0.4mN /} μm 2, the hysteresis curve measured at four different pressures of 0.6mN / μm ² and 0.8mN / μm ^2, the elastic recovery rate in each Ask for.

  The total deformation amount of the photo spacer of the present invention is preferably 0.5 to 2.5 μm, more preferably 0.75 to 2.0 μm, and particularly preferably 1.0 to 1.5 μm under a pressure condition of 1.5 GPa. It is. If the total deformation amount is 0.5 μm or more, there is a high possibility that it can be used practically as a spacer for holding the liquid crystal cell gap.

  The elastic recovery rate of the photospacer of the present invention is usually 60% or more, preferably 65% or more, particularly preferably 70% or more under a pressure condition of 1.5 GPa. If the elastic recovery rate is 60% or more, particularly 65% or more, there is a high possibility that it can be used as a spacer for holding the liquid crystal cell gap without problems in practice.

[Example]
EXAMPLES Hereinafter, although an Example and a manufacture example demonstrate this invention concretely, this invention is not limited to these. Hereinafter, the part means part by weight.

[Production of hydrophilic resin (A)]
<Production Example 1>
A glass Kolben equipped with a heating / cooling / stirring measure, a reflux condenser, a dropping funnel and a nitrogen inlet tube, isobornyl methacrylate 50 parts (33 mol%), 2-hydroxyethyl methacrylate 30 parts (33 mol%), methacryl 20 parts (34 mol%) of acid and 150 parts of cyclohexanenone were charged and heated to 80 ° C. A solution in which 5 parts of azobisisobutyronitrile (V-60: Wako Pure Chemical Industries, Ltd., hereinafter referred to as AIBN) prepared in advance is dissolved in 50 parts of cyclohexanone after replacing the gas phase part in the system with nitrogen. 55 parts were dropped into Kolben at 80 ° C. over 10 minutes, and further reacted at the same temperature for 3 hours to obtain a hydrophilic polymer (A-1) having a hydroxyl group and a carboxyl group ((meth) acryloyl group concentration: 0 mmol / g, A cyclohexanone solution (Mn: 8,800, SP value: 11.86, HLB value: 11.98, acid value: 102 mgKOH / g) was obtained (the solid content was 25%). In addition, Mn is GPC measurement equipment (HLC-8120GPC, manufactured by Tosoh Corp.), column (TSKgel GMHXL 2 + TSKgel Multipore HXL-M, manufactured by Toso Corp.), polystyrene conversion measured by GPC method. Obtained as a value. The SP value, HLB value, and acid value were determined as described above. The same measurement method is used for the following production examples and comparative examples.

<Production Example 2>
In the same Kolben as in Production Example 1, 200 parts of a cresol novolac type epoxy resin “EOCN-1020” (manufactured by Nippon Kayaku, epoxy equivalent 200) and 245 parts of propylene glycol monomethyl ether acetate are charged and heated to 110 ° C. uniformly. Dissolved. Subsequently, 76 parts (1.07 mol part) of acrylic acid, 2 parts of triphenylphosphine, and 0.2 part of p-methoxyphenol were charged and reacted at 110 ° C. for 10 hours. The reaction product was further charged with 91 parts (0.60 mol part) of tetrahydrophthalic anhydride, further reacted at 90 ° C. for 5 hours, and after cooling, propylene glycol monomethyl ether acetate was added to adjust the solid content, and carboxyl group and acryloyl Group-containing hydrophilic polymer (A-2) ((meth) acryloyl group concentration: 3.2 mmol / g, Mn: 2,200, SP value: 11.26, HLB value: 6.42, acid value: 91 mgKOH / A propylene glycol monomethyl ether acetate solution of g) was obtained (solid content 25%).

[Production of polysiloxane (D) having hydrolyzable alkoxy groups]
<Production Example 3>
In the same Kolben as in Production Example 1, 47 parts (0.2 mol parts) of 3-acryloyloxypropyltrimethoxysilane, 159 parts (0.65 mol parts) of diphenyldimethoxysilane and 45 g of ion-exchanged water (2.5 mols) Part) and 0.1 part (0.001 mol part) of oxalic acid, and heated and stirred at 60 ° C. for 6 hours. Further, by using an evaporator, methanol produced as a by-product by hydrolysis was reduced under a reduced pressure of 50 mmHg. For 2 hours. Then, it dilutes with cyclohexanone so that solid content may be 25%, polysiloxane (D-1) ((meth) acryloyl group concentration: 1.0 mmol / g, Mn: 2,100, viscosity: 20 mPa · s. , SP value: 9.36) was obtained (solid content 25%). The viscosity was measured using a BL type viscometer (manufactured by Toki Sangyo Co., Ltd.) at a constant temperature of 25 ° C. The same measurement method is used for the following production examples and comparative examples.

<Production Example 4>
In the same Kolben as in Production Example 1, 170 parts (0.82 mole part) of 3-glycidoxypropyltrimethoxysilane, 40 parts (0.20 mole part) of phenyltrimethoxysilane, 30 parts of diphenyldimethoxysilane (0. 12 mol parts), 40 g (2.2 mol parts) of ion-exchanged water, and 0.1 part (0.001 mol parts) of oxalic acid, and the mixture is heated and stirred at 60 ° C. for 6 hours, and an evaporator is used. Then, methanol by-produced by hydrolysis was removed under reduced pressure of 50 mmHg over 2 hours. Then, it dilutes with cyclohexanone so that solid content may be 25%, polysiloxane (D-2) ((meth) acryloyl group concentration: 0 mmol / g, Mn: 7,800, viscosity: 70 mPa · s, SP A cyclohexanone solution with a value of 8.69) was obtained (solid content 25%).

<Comparative Production Example 1>
In the same Kolben as in Production Example 1, 200 parts of cresol novolac resin (EP-4020G manufactured by Asahi Organic Materials Co., Ltd.) and 238 parts of propylene glycol monomethyl ether acetate were charged and heated to 110 ° C. to be uniformly dissolved. Subsequently, 0.1 part of dibutyltin dilaurate and 20 parts of isocyanatoethyl methacrylate were added, reacted at 60 ° C. for 5 hours, and then diluted with propylene glycol monomethyl ether acetate to a solid content of 25%. Resin having an acryloyl group (A-1 ′: acryloyl group concentration: 0.6 mmol / g, Mn: 2,100, SP value: 13.46, HLB value: 6.41, acid value: 0 mgKOH / g, acryloyl A propylene glycol monomethyl ether acetate solution having a base concentration of 1.34 mmol / g) was obtained (the solid content was 25%).

<Examples 1-5 and Comparative Examples 1-5>
[Production of photosensitive resin composition]
According to the formulation example of Table 1, each hydrophilic polymer solution and polysiloxane solution are charged into a glass container, and the following (B-1), (B-2), and (C-1) are further charged. Stir until uniform, and further add an additional solvent (propylene glycol monomethyl ether acetate), photosensitive resin compositions (Q1) to (Q5) of Examples, and photosensitive resin composition (Y1) of Comparative Examples -(Y5) was manufactured.

B-1 (polyfunctional (meth) acrylate): “Neomer DA-600” (mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate: Sanyo Chemical Industries, Ltd.) ((meth) acryloyl group concentration: 9 .9 mmol / g)
B-2 (polyfunctional (meth) acrylate): “DPCA-120” (polycaprolactone-modified dipentaerythritol hexaacrylate: manufactured by Nippon Kayaku Co., Ltd.) ((meth) acryloyl group concentration: 3.1 mmol / g)
C-1 (photo radical polymerization initiator): “Irgacure 907” (2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one: manufactured by Ciba Specialty Chemicals Co., Ltd. )

Evaluation Examples 1-5, Comparative Evaluation Examples 1-5
[Measurement of developability]
The photosensitive resin compositions (Q1) to (Q5) and (Y1) to (Y5) were each spin-coated on a glass substrate so that the finished film thickness was 5 μm, dried at 25 ° C. for 5 minutes, and then Development was performed for 30 seconds using a 1% aqueous sodium carbonate solution to evaluate developability. The results are shown in Table 1. The evaluation criteria are as follows.
A: There is no residue visually.
○: There is a slight residue visually.
Δ: There are many residues by visual inspection.

Examples 6-10, Comparative Examples 6-10
[Production of photo spacer]
The photosensitive resin compositions (Q1) to (Q5) and (Y1) to (Y5) were each spin-coated on a glass substrate so that the finished film thickness was 5 μm, and dried at 25 ° C. for 5 minutes. The light of a high pressure mercury lamp was 100 mJ / cm ² irradiation through a photomask for forming photo spacers. The exposure was performed with a gap (exposure gap) between the photomask and the substrate of 100 μm. Thereafter, development was performed using a 1% aqueous sodium carbonate solution. After washing with water, post-baking was performed at 230 ° C. for 60 minutes to form a photo spacer on the color filter. The upper base area of the photo spacer was 150 μm ² and the lower base area was 400 μm ² .

[Measurement of total deformation and elastic recovery rate]
The total deformation amount and elastic recovery rate of the photo spacer obtained as described above were measured using a Fischer scope H-100 (Fischer Instruments) apparatus.
A flat indenter (50 μm × 50 μm) having a square cross section was used. The results are shown in Tables 2 and 3.

Examples 11-15, Comparative Examples 11-15
[Preparation of cured coating film]
The photosensitive resin compositions (Q1) to (Q5) and (Y1) to (Y5) were each spin-coated on a glass substrate so as to have a finished film thickness of 5 μm. / Cm 2 irradiation. The exposure was performed with a gap (exposure gap) between the photomask and the substrate of 100 μm. Thereafter, post-baking was performed at 230 ° C. for 60 minutes to prepare a cured coating film.

[Measurement of adhesion]
Create a grid (10 x 10) by cutting the cured coating into a 1mm width with a knife, apply cellophane adhesive tape on the grid and peel it 90 degrees, and then cure the cured product (film) ) Was observed and evaluated.
○ All grids do not peel. △ 1-10 grids peel. × 11 grids or more peel.

As can be seen from Table 1, Table 2, Table 3 and Table 4, by using the photosensitive resin composition of the present invention, a photo spacer having good developability and excellent flexibility, elastic recovery characteristics and adhesion. Can be formed.
In Comparative Example 1, no hydrophilic polymer is used and the developability is poor. In Comparative Examples 2 and 5, the (meth) acryloyl group concentration is insufficient and the elastic recovery characteristics are poor. In Comparative Example 3, the (meth) acryloyl group concentration is too high and the adhesion is poor. In Comparative Example 4, the polyfunctional (meth) acrylate monomer is not used and the elastic recovery characteristics are poor. When a liquid crystal panel is produced using such a photo spacer, the cell gap is not uniform and the display quality is deteriorated. In addition, it is difficult to maintain display quality for a long time.

  The photosensitive resin composition of this invention can be used conveniently for photospacers. In addition, it is also suitable as a photosensitive resin composition for uses such as various resist materials such as a photo solder resist, a photosensitive resist film, a photosensitive resin relief plate, a screen plate, a photoadhesive or a hard coat agent. Furthermore, coating agents for various materials such as metals (eg, iron, aluminum, titanium, copper, etc.), plastics (eg, polycarbonate, polyethylene terephthalate, poly (meth) acrylate), paper, glass, rubber and wood, paints, It can also be used as a printing ink and an adhesive, and can also be applied as a molding material.

Hysteresis curve of load and deformation

Explanation of symbols

T ₀ : Total deformation amount T ₁ : Plastic deformation amount T ₂ : Elastic deformation amount

Claims (5)

A photosensitive resin composition containing a hydrophilic resin (A), a polyfunctional (meth) acrylate monomer (B), and a radical photopolymerization initiator (C), and the weight of the solid content of the photosensitive resin composition The (meth) acryloyl group concentration based is 2.0 to 5.5 mmol / g, and the photo-spacer formed by photocuring the photosensitive resin composition is elastically restored to a compression load of 1.5 Gpa. A photosensitive resin composition (Q) for photospacers capable of alkali development, having a rate of 60% or more. The photosensitive resin composition according to claim 1, wherein the hydrophilic resin (A) is a hydrophilic resin containing a (meth) acryloyl group and a carboxyl group obtained by modifying an epoxy resin. Based on the weight of the solid content of the photosensitive resin composition, the hydrophilic resin (A) is 40 to 89% by weight, the polyfunctional (meth) acrylate monomer (B) is 10 to 59% by weight, and a radical photopolymerization initiator. The photosensitive resin composition of Claim 2 or 3 which contains 0.01-10 weight% of (C). Furthermore, it contains a polysiloxane (D1) having a hydrolyzable alkoxy group, and the polysiloxane (E1) is a condensate containing a silane compound (d1) represented by the following general formula (1) as an essential constituent monomer. The photosensitive resin composition according to any one of claims 1 to 3.

[In the formula, R ¹ (meth) acryloyloxy group, glycidoxy group, mercapto group, and one or more organic groups selected from the group consisting of aminoalkyl groups, R ² is 1 to the number of carbon atoms 12 aliphatic saturated hydrocarbon groups or aromatic hydrocarbon groups having 6 to 12 carbon atoms, R ³ is an alkyl group having 1 to 4 carbon atoms, and m is 0 or 1. ] The photo spacer provided in order to maintain the gap in the liquid crystal cell formed by hardening the photosensitive resin composition in any one of Claims 1-4.

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