JP2011203578A - Photosensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition for a photospacer that has high alkaline developability, high exposure sensitivity, and high resolution, and is excellent in adhesion to a substrate and elastic recovery characteristics even when the cured product employs low-temperature processing.SOLUTION: This photosensitive resin composition (Q) for the photospacer is a photosensitive resin composition of negative type and alkaline developability including hydrophilic epoxy resin (A), multi-functional (meta) acrylate monomer (B), cationic polymerizable compound (C) containing two or more epoxy groups and/or alkoxy groups in a molecule, siloxane compound (D) having two or more hydrolysis alkoxy groups, a photo-radical polymerization initiator (E), and acid generator (F). The elastic recovery rate of the photospacer formed by post-baking the cured product by light irradiation at 200°C or lower is 50% or more.

Description

  The present invention relates to a negative photosensitive resin composition 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. . More specifically, it has excellent elastic recovery characteristics and adhesion to the substrate, and can exhibit excellent elastic recovery characteristics and adhesion to the substrate even when post-baking treatment at low temperature is adopted after curing by light irradiation. The present invention relates to a photo spacer.

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 portion, a so-called negative resist is often used in which only a portion irradiated with light is hardened when exposed through a mask and an unexposed portion is peeled off by development.
In the liquid crystal display device technology, in order to maintain the thickness of the liquid crystal layer between the substrate on the color filter side and the substrate on the thin film transistor (TFT) side, glass or resin called a spacer is disposed inside the cell.
For example, a method of forming a columnar resin spacer on a black matrix in a lattice pattern located at a desired position, for example, between pixels by a photolithography method using a photosensitive resin and partial pattern exposure and development Has been proposed. Since such a spacer (hereinafter referred to as a photo spacer) can be formed at a position that does not overlap with the pixel, there is no problem that adversely affects display quality such as light leakage caused by mixing of liquid crystal and spacer in the pixel. The improvement of quality can be expected.

On the other hand, in recent years, as mother glass for LCD (Liquid Crystal Display) manufacture becomes larger, a drop method (ODF method) (ODF: One Drop Fill) has been proposed instead of the conventional liquid crystal inflow method (vacuum suction method). Yes. In the ODF method, after a predetermined amount of liquid crystal is dropped onto the substrate and then sandwiched between the substrates, the liquid crystal is injected, so that the number of processes and the process time can be reduced as compared with the conventional liquid crystal inflow method.

However, in the ODF system, when a predetermined amount of liquid crystal calculated from the cell gap is dropped and held, a delicate pressure difference is applied in the surface. It is desired that the photo spacer itself has elastic properties.
That is, a photo spacer having a high total deformation amount and a high elastic recovery characteristic is required for pressing and unloading when a panel for holding a liquid crystal between substrates is produced. 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 liquid crystal display device has problems such as uneven color.

As a material for forming a photospacer having a characteristic that solves this problem, there has been proposed improvement by increasing the amount of monomer (for example, Patent Document 1).
However, when many polyfunctional monomers like the above proposal are used, there is a problem that the adhesion between the spacer and the substrate deteriorates.

In recent years, LCDs have become smaller and more precise, and the pixel size has been reduced to maintain display quality. Therefore, exposure sensitivity and resolution require patterning with a size of 10 μm or less. Has been.
In addition, since the ground contact area between the substrate and the spacer has been reduced, further adhesion is required, and since the spacer diameter has been reduced, further elastic recovery characteristics have been required.
However, it is known that the elastic recovery characteristic is lowered when trying to improve the adhesion.

In recent years, with the widespread use of portable personal computers, mobile phones, personal digital assistants (PDAs), portable game machines, etc., the required performance of display quality has become stricter and the weight of color liquid crystal display devices has been reduced. There is an increasing demand for reduction in manufacturing costs.
Therefore, an attempt has been made to use a resinous substrate instead of a conventionally used glass substrate.

However, when a conventionally known photosensitive resin composition for spacers is used to form spacers on a resin substrate, a high temperature is required during post-baking in the spacer forming step, so that deformation or yellowing of the substrate may occur. There was a problem that happened.
If the temperature during post-baking in the spacer formation process is lowered to avoid deformation and yellowing of the resin substrate and reduce the manufacturing cost, the elastic recovery characteristics of the formed spacer will decrease, and the adhesion to the substrate will decrease. There was a problem that a problem occurred.

As a material for forming a photospacer having the characteristics to solve these problems, a method using a polymerizable compound having an ethylenically unsaturated bond having a specific cyclic structure (Patent Document 2) or a specific onium-based phosphoric acid Proposals have been made to improve elastic recovery characteristics and adhesion to a substrate even when the temperature during post-baking is 200 ° C. or less by using a salt and a polymerizable compound having an ethylenically unsaturated bond in combination (Patent Document 3). Yes.
However, it is known that when the spacer diameter is reduced, the elastic recovery characteristics and the adhesion to the substrate are lowered.

For this reason, in the improvements as described in Patent Documents 2 and 3, when the spacer diameter is reduced to obtain a spacer diameter of 10 μm or less, that is, a high-resolution photo spacer, the elastic recovery characteristics and the adhesion to the substrate are obtained. Has the problem of insufficient.
Thus, with regard to the negative-type photosensitive resin composition that can be developed in the past, after curing by light irradiation, excellent elastic recovery even when post-baking treatment is adopted at a low temperature of 200 ° C. or lower Nothing that can exhibit the characteristics and adhesion to the substrate is known.

JP 2002-174812 A JP 2009-186838 A JP 2009-75284 A

Therefore, the alkali developability is good, the sensitivity is high, the resolution is high, and even when a low temperature treatment of 200 ° C. or lower is adopted after curing by light irradiation, the cured product and the substrate have excellent adhesion, and It is an object of the present invention to provide a photosensitive resin composition for a photospacer having excellent elastic recovery characteristics, and to provide a photospacer having excellent adhesiveness with a substrate and having excellent elastic recovery characteristics.

The inventors of the present invention have reached the present invention as a result of studies to achieve the above object.
That is, the present invention relates to a hydrophilic epoxy resin (A) having one or more (meth) acryloyl groups and one or more carboxyl groups in the molecule, a polyfunctional (meth) acrylate monomer (B), an epoxy group and / or Or a cationically polymerizable compound (C) having two or more alkoxy groups in the molecule, a siloxane compound (D) having two or more hydrolyzable alkoxy groups, a photoradical polymerization initiator (E), and an acid generator This is a negative photosensitive resin composition (Q) for photospacers which has (F) as an essential component and is excellent in alkali developability and resolution. Furthermore, the photosensitive resin composition for photospacers (Q) wherein the elastic recovery rate of a photospacer formed by post-baking a cured product by light irradiation at 200 ° C. or less in the present invention is 50% or more. And a photo spacer provided for maintaining a gap in a liquid crystal cell formed by curing the same.

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.
-The photosensitive resin composition is excellent in resolution.
-Even when a low temperature treatment of 200 ° C. or lower is adopted after curing by light irradiation, the photo spacer obtained in the present invention has excellent adhesion to the substrate and excellent elastic recovery characteristics.

The photosensitive resin composition (Q) for photospacers of the present invention comprises a hydrophilic epoxy resin (A) having one or more (meth) acryloyl groups and one or more carboxyl groups in the molecule, and a polyfunctional (meth) acrylate monomer. (B), a cationic polymerizable compound (C) having two or more epoxy groups and / or alkoxy groups in the molecule, a siloxane compound (D) having two or more hydrolyzable alkoxy groups, and a radical photopolymerization initiator This is a negative photosensitive resin composition (Q) for photospacers which contains (E) and an acid generator (F) as essential components and is excellent in alkali developability and resolution. Furthermore, the photosensitive resin composition (Q) of the present invention provides a photo spacer excellent in adhesion to a substrate and elastic recovery characteristics even when a low temperature treatment of 200 ° C. or lower is adopted after curing by light irradiation. be able to.

In the present specification, the expression “(meth) acrylate” with (meth) means “acrylate or methacrylate”.
Further, “content of carbon-carbon double bond (C═C) in (meth) acryloyl group” may be simply referred to as “(meth) acryloyl group concentration”.

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

  The hydrophilic epoxy resin (A) which is an essential component of the present invention is a hydrophilic epoxy resin having one or more (meth) acryloyl groups and one or more carboxyl groups as essential components in the molecule.

The hydrophilicity index in the hydrophilic epoxy resin (A) of the present invention is defined by HLB. Generally, the larger this value, the higher the hydrophilicity.
The preferred range of the HLB value of the hydrophilic epoxy resin (A) varies depending on the resin skeleton of the hydrophilic epoxy resin (A) (for example, vinyl resin, epoxy resin, polyester resin, etc.), but preferably 4 to 14, More preferably, it is 5-13, Most preferably, it is 6-12. When it is 4 or more, the developing property is further improved when developing the photo spacer, and when it is 14 or less, the water resistance of the cured product is further improved.

Here, “HLB” is an index indicating the balance between hydrophilicity and lipophilicity, and is calculated by the Oda method described in “Introduction to Surfactants” (2007, Takehiko Fujimoto), item 212. And is not a calculated value by the Griffin method.
The HLB value can be calculated from the ratio between the organic value and the inorganic value of the organic compound.
HLB≈10 × Inorganic / Organic values for deriving organic HLB and inorganic values are described in “Introduction to Surfactant” (2007, Takehiko Fujimoto), page 213. It can be calculated.

  Moreover, the solubility parameter (henceforth SP value) of hydrophilic epoxy resin (A) becomes like this. Preferably it is 7-14, More preferably, it is 8-13, Most preferably, it is 11-13. 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. 147-154)"

  The hydrophilic group possessed by the hydrophilic epoxy resin (A) of the present invention includes, in addition to the essential carboxyl group, a hydroxyl group, amino group, amide group, urethane group, urea group, epoxy group, polyether group, sulfonic acid group, sulfuric acid group. Examples thereof include an ester group, a phosphoric acid group, and a phosphoric acid ester group. Furthermore, you may contain more carboxyl groups. Of these hydrophilic groups, from the viewpoint of alkali developability, an epoxy group, a sulfonic acid group, and an additional carboxyl group are preferable, and a carboxyl group is more preferable.

The carboxyl group content of the hydrophilic epoxy resin is indicated by an acid value. The acid value of the hydrophilic epoxy resin (A) is preferably 10 to 500 mgKOH / g, more preferably 15 to 300 mgKOH / g, and particularly preferably 20 to 150 mgKOH / g. Within this range, the developability is more easily exhibited, and 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
Where A is the number of mL of the 0.1 mol / L potassium hydroxide titration solution, f is the titer of the 0.1 mol / L potassium hydroxide titration solution, S is the sampled amount (g) [where the sample is the solvent Is included, the amount excluding the solvent (g)].

A preferred method for producing a hydrophilic epoxy resin (A) having at least one (meth) acryloyl group and a carboxyl group in the molecule includes (meth) acryloyl group in the epoxy group in the raw material epoxy resin (A ₀ ). A monocarboxylic acid (a) is reacted to open an epoxy group to form a hydroxyl group, and a polyvalent carboxylic acid or polyvalent carboxylic acid is added to a part of the hydroxyl group of the (meth) acrylic acid adduct of (A ₀ ). In this method, the anhydride (e) is reacted.

Examples of the epoxy resin (A ₀ ) include aliphatic epoxy resins [for example, Epototo YH-300, PG-202, PG-207 (all manufactured by Toto Kasei Co., Ltd.)] and alicyclic epoxy resins [for example, CY-179, CY. -177, CY-175 (both manufactured by Asahi Kasei Epoxy Co., Ltd.)] and aromatic epoxy resins [for example, phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol A epoxy resin, biphenyl type epoxy resin, glycidyl-modified polyvinylphenol, etc.] Is mentioned.
Among these, aromatic epoxy resins are preferable from the viewpoint of curability.

As said (meth) acryloyl group containing monocarboxylic acid (a) used for manufacture of a hydrophilic epoxy resin (A), acrylic acid, methacrylic acid, 2-acryloyloxyethyl succinic acid, etc. are mentioned.

The polyvalent carboxylic acid and polyvalent carboxylic acid anhydride (e) used in the production of (A) include unsaturated polyvalent carboxylic acids and their anhydrides, and saturated polyvalent (2-6 valent) carboxylic acids. (For example, aliphatic saturated polycarboxylic acids such as oxalic acid, succinic acid, phthalic acid, adipic acid, dodecanedioic acid, dodecenyl succinic acid, pentadecenyl succinic acid, octadecenyl succinic acid; tetrahydrophthalic acid, hexahydro Phthalic acid, methyltetrahydrophthalic acid, trimellitic acid, pyromellitic acid, biphenyltetracarboxylic acid, aromatic polycarboxylic acid such as naphthalenetetracarboxylic acid), and their anhydrides (for example, succinic anhydride, dodecenyl succinic anhydride) Aliphatic saturated polycarboxylic acid anhydrides such as pentadecenyl succinic anhydride and octadecenyl succinic anhydride; phthalic anhydride , Aromatic polycarboxylic anhydrides such as tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, biphenyltetracarboxylic anhydride, naphthalenetetracarboxylic anhydride ) And the like.
Of these, saturated polyvalent carboxylic acid anhydrides are preferable from the viewpoints of reactivity and developability.

In the preparation of (A), the charged weight ratio of (meth) acryloyl group-containing monocarboxylic acid (a) / (A ₀ ) is preferably such that the concentration of (meth) acryloyl group in (A) is 1.0 mmol. It is a preparation weight ratio which becomes more than / g.
From the above viewpoint, the weight ratio of (meth) acryloyl group-containing monocarboxylic acid / (A ₀ ) is preferably 0.072 or more / 1, and more preferably 0.079 to 0.72 / 1. Further, the weight ratio of the (meth) acryloyl group-containing monocarboxylic 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 of the aforementioned (A ₀ ) and the (meth) acryloyl group-containing monocarboxylic acid (a) 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. 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 (A ₀ ) is preferably the acid value of (A), preferably 10 The charge equivalent of (e) such that it is ˜500 mg KOH / g. For example, when (e) is a divalent carboxylic acid or an anhydride thereof, the charge equivalent of (e) / (meth) of (A ₀ ) From the above viewpoint, the weight of the acrylic acid adduct is preferably 0.18 to 8.9 meq / g, more preferably 0.53 to 7.1 meq / g.

The reaction temperature in the reaction of the raw material (A 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.

  The number average molecular weight (hereinafter referred to as Mn) of the above (A) is usually 500 to 3,000, preferably 1,000 to 2 from the viewpoint of photocuring reactivity and developability as the photosensitive resin composition. 800, particularly preferably 1,500 to 2,500.

Mn is a value in terms of polystyrene measured by the GPC method using a GPC measuring device (HLC-8120GPC, manufactured by Tosoh Corporation) and a column (2 TSKgel GMHXL + TSKgel Multipore HXL-M, manufactured by Tosoh Corporation). As sought.

The content of (A) based on (A) to (F) of the photosensitive resin composition (Q) is usually 10 to 80% by weight, preferably 10 to 70% by weight, more preferably 20 to 50% by weight, Most preferably, it is 20-40 weight%. Within this range, alkali developability and adhesion to the substrate can be satisfactorily exhibited.

The polyfunctional (meth) acrylate monomer (B), which is the second essential component of the present invention, is not particularly limited as long as it is a known polyfunctional (meth) acrylate monomer. B1), trifunctional (meth) acrylate (B2), 4-6 functional (meth) acrylate (B3), and a mixture containing two or more of these.

As the bifunctional (meth) acrylate (B1), an esterified product of a dihydric alcohol and (meth) acrylic acid [for example, di (meth) acrylate of ethylene glycol, di (meth) acrylate of diethylene glycol, di (meth) of propylene glycol Acrylate, di (meth) acrylate of dipropylene glycol]; esterified product of polyalkylene oxide of dihydric alcohol and (meth) acrylic acid [for example, di (meth) acrylate of polyethylene glycol, di (meth) acrylate of polypropylene glycol]; Trivalent or higher polyhydric alcohol and (meth) acrylic acid esterified product [eg, di (meth) acrylate of neopentyl glycol, di (meth) acrylate of glycerin]; trihydric or higher polyhydric alcohol and (meth) acrylic acid of Carboxylic acid modified products obtained by adding carboxylic anhydride to stearides [for example, glycerin carboxylic acid modified di (meth) acrylate, neopentyl glycol carboxylic acid modified di (meth) acrylate]; linear fat Esterified product of aromatic diol and (meth) acrylic acid [for example, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) Acrylate, di (meth) acrylate of 1,10-decanediol]; esterified product of aliphatic diol having side chain and (meth) acrylic acid [for example, di (meth) acrylate of 3-methyl-1,5-pentanediol , Di (meth) acrylate of 2-butyl-2-ethyl-1,3-propanediol]; alicyclic charcoal Esters of hydrogen diol and (meth) acrylic acid [eg dimethylol-tricyclodecane di (meth) acrylate]; Aromatic hydrocarbon diol and (meth) acrylic acid ester [eg bisphenol A di (meth) ) Acrylate]; esterified product of polyhydric alcohol and (meth) acrylic acid [for example, di (meth) acrylate of ethylene oxide adduct of bisphenol A, di (meth) acrylate of propylene oxide adduct of bisphenol A, ethylene of pentaerythritol Di (meth) acrylate of an oxide adduct]; esterified product of polyhydric alcohol, (meth) acrylic acid and hydroxycarboxylic acid [for example, hydroxypivalic acid neopentyl glycol di (meth) acrylate]; Relates and the like.
Among these (B1), polypropylene glycol diacrylate and OH group-containing both-end epoxy acrylate are preferable from the viewpoint of improving the adhesion between the cured product and the substrate.

Trifunctional (meth) acrylate (B2) includes tri (meth) acrylate of glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ethylene oxide adduct of trimethylolpropane And carboxylic acid-modified tri (meth) acrylate of pentaerythritol.
Among these (B2), from the viewpoint of photocuring reactivity as the photosensitive resin composition, pentaerythritol triacrylate and trimethylolpropane triacrylate are preferable, and from the viewpoint of adhesion to the substrate and photocuring reactivity, More preferred is pentaerythritol triacrylate.

Examples of the 4- to 6-functional (meth) acrylate (B3) include pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol carboxylic acid-modified penta ( And (meth) acrylates and poly (meth) acrylates of these alkylene oxide adducts.
Among these (B3), from the viewpoint of photocuring reactivity as the photosensitive resin composition, dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, and propylene adduct dipentaerythritol hexaacrylate are preferable. From the viewpoints of adhesion and photocuring reactivity, dipentaerythritol pentaacrylate is more preferable.

Preferred among the polyfunctional (meth) acrylate monomer (B) are (B2) and (B3), and more preferred are those described later from the viewpoint of compatibility with (A) and (C) to (E). A mixture containing a hydrophilic group and a mixture containing no hydrophilic group. Particularly preferred are dipentaerythritol pentaacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, and combinations thereof.

As (B) which can be easily obtained from the market, for example, Aronix M-403 (manufactured by Toagosei Co., Ltd .: pentaerythritol triacrylate), light acrylate PE-3A (manufactured by Kyoeisha Chemical Co., Ltd .: pentaerythritol triacrylate) , Neomer DA-600 (manufactured by Sanyo Chemical Industries, Ltd .: a mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate) and the like.

Of the polyfunctional (meth) acrylate monomer (B), examples of the hydrophilic group possessed by the polyfunctional (meth) acrylate monomer (B) containing a hydrophilic group include a hydroxyl group, an amino group, and a polyether group. Of these hydrophilic groups, a hydroxyl group and a polyether group are preferable, and a hydroxyl group is more preferable.

In addition, (B) in the present invention may be used in combination with the photosensitive acrylic oligomer (B4) in addition to the above (B1) to (B3).
Examples of the photosensitive acrylic oligomer (B4) include urethane acrylate and polyester acrylate having Mn of 1,000 or less and having two or more acryloyl groups in one molecule.

The content of (B4) in (B) is preferably 50% by weight or less, more preferably 30% by weight or less.

The content of (B) based on (A) to (F) of the photosensitive resin composition (Q) is usually 10 to 80% by weight or less, preferably 20 to 80% by weight, more preferably 30 to 70% by weight. Particularly preferred is 40 to 60% by weight. Within this range, alkali developability, elastic recovery characteristics of the cured product, and adhesion to the substrate can be satisfactorily exhibited.

In the present invention, the cationic polymerizable compound (C) contained as a component in the photosensitive resin composition (Q) includes one or more reactive functional groups selected from the group consisting of epoxy groups and alkoxy groups. It is a compound having 2 or more in total in the molecule.
That is, the cationically polymerizable compound (C) has at least two epoxy groups, two or more alkoxy groups, or one or more epoxy groups and one or more alkoxy groups in the molecule.

  High adhesion and high elastic recovery characteristics are exhibited by the occurrence of crosslinking by a cationic reaction such as a reaction between epoxy groups or a polycondensation reaction between alkoxy groups in the cationically polymerizable compound (C). In addition, crosslinking by reaction between an epoxy group and an alkoxy group and crosslinking by reaction between an epoxy group or an alkoxy group and a hydrophilic group in the hydrophilic epoxy resin (A) are effective in further improving adhesion and elastic recovery characteristics. Inferred.

As such a cationically polymerizable compound (C), a melamine derivative (C1) represented by the following general formula (1), an aliphatic cationically polymerizable compound (C2), a cationically polymerizable compound (C3) having an aromatic ring, Examples thereof include a cationically polymerizable compound (C4) having an alicyclic structure, but it is not particularly limited as long as it is a known compound having two or more epoxy groups and / or alkoxy groups in the molecule as described above. Used for.

[R ^{1 to} R ⁶ each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a glycidyl group, and the total number of alkyl groups or glycidyl groups is 2 to 6. ]

R ^{1 to} R ⁶ in the compound represented by the general formula (1) are preferably an alkyl group having 1 to 3 carbon atoms and a glycidyl group, more preferably from the viewpoint of curability and elastic recovery properties. , An alkyl group having 1 to 2 carbon atoms.

As the melamine derivative (C1) represented by the general formula (1), for example, a part or all of the methylol group of methylolated melamine is a monohydric alcohol having 1 to 8 carbon atoms [for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, 2-ethylbutanol, and 2-ethylhexanol], and partially etherified or fully etherified melamine resins.
As these, all of the methylol groups may be etherified or partially etherified so that the methylol group remains. Examples include alkyl etherified melamines such as methyl etherified melamine, ethyl etherified melamine, and butyl etherified melamine. Among these, methyl etherified melamine is preferable from the viewpoint of curability.

  Examples of the aliphatic cation polymerizable compound (C2) include an aliphatic epoxy compound having an Mn of 1,000 or less [for example, an aliphatic alcohol or an alkylene oxide (hereinafter abbreviated as AO) adduct polyglycidyl ether ( Hereinafter, glycidyl ether is abbreviated as GE), polyglycidyl ester of aliphatic long-chain polybasic acid having 8 to 24 carbon atoms (hereinafter, glycidyl ester is abbreviated as GS), homopolymer of glycidyl (meth) acrylate, And copolymers of glycidyl (meth) acrylate and other vinyl monomers], aliphatic cationic polymerizable compounds having a total of five or more alkoxy groups and epoxy groups [for example, triGE of dipentaerythritol trialkoxy, dipentaerythritol pentaalkoxy ],and Serial compound represented by the general formula (2) (C21) can be mentioned.

In formula (2), A ^{1 to} A ⁴ each independently represent a hydrogen atom or —CH ₂ OR ⁷ .
R ⁷ in the —CH ₂ OR ⁷ group represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a glycidyl group, and R ⁷ contained in A ^{1 to} A ⁴ is the same or different. May be.

  Typical aliphatic epoxy compounds include, for example, ethylene diGE, butylene diGE, hexyl diGE, 1,4-butanediol diGE, 1,6-hexanediol diGE, hydrogenated bisphenol A diGE, glycerol triGE, Trimethylolpropane tri-GE, sorbitol tetra-GE, pentaerythritol penta-GE, dipentaerythritol hexa-GE, dipentaerythritol penta-GE, polyethylene glycol di-GE, polypropylene glycol di-GE, aliphatic polyhydric alcohol ( Poly GE of AO adduct of propylene glycol, trimethylol propane, glycerin, etc.), diGS of aliphatic long chain dibasic acid having 8 to 24 carbon atoms, poly GS of higher fatty acid, and epoxidized soybean oil.

A ^{1 to} A ⁴ in the compound (C21) represented by the general formula (2) each independently represents a hydrogen atom or —CH ₂ OR ^7, and —CH ₂ OR ⁷ among A ^{1 to} A ^4. Is 2 to 4.
R ⁷ represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a glycidyl group. R ⁷ in A ^{1 to} A ⁴ may be the same or different. From the viewpoint of curability and elastic recovery properties, —CH ₂ OR ⁷ is preferred.
Further, from the viewpoint of further improving the curability and the elastic recovery property, R ⁷ is preferably an alkyl group or a glycidyl group, and particularly preferably a glycidyl group.
In order for compound (C21) to act as a cross-linking agent, at least two or more glycidyl groups and alkoxy groups are required. Of 2 to 4 R ⁷ groups in —CH ₂ OR ⁷ group, an alkyl group or glycidyl group The total number of groups should be 2-4.

R ⁷ is preferably an alkyl group having 1 to 3 carbon atoms and a glycidyl group, more preferably an alkyl group having 1 to 2 carbon atoms, and a glycidyl group, storage stability, from the viewpoints of curability and elastic recovery properties. In view of the above, a glycidyl group is particularly preferable.

  As a typical compound represented by the general formula (2), for example, part or all of the hydroxyl groups of pentaerythritol or glycerin may be monovalent alcohol having 1 to 8 carbon atoms [for example, methyl alcohol, ethyl alcohol, n- Partial etherification etherified with propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, 2-ethylbutanol, and 2-ethylhexanol] and / or glycidyl compounds [eg epichlorohydrin] Or the compound fully etherified is mentioned.

These may be used in which all hydroxyl groups are etherified or partially etherified and the hydroxyl groups remain. Examples include alkyl etherified or glycidyl etherified pentaerythritol, such as methyl etherified glycerin, glycidyl etherified pentaerythritol, glycidyl etherified glycerin, and alkyl etherified or glycidyl etherified glycerin. Among these, glycidyl etherified pentaerythritol is preferable from the viewpoint of curability.

As the cationically polymerizable compound (C3) having an aromatic ring, for example, a phenol having at least one aromatic ring, or an alkylene oxide (hereinafter abbreviated as AO) adduct (poly) glycidyl ether [phenol, Bisphenol A, bisphenol F, and (poly) glycidyl ethers of these AO adducts, etc.], phenol novolac epoxy resins, o-, p-, m-cresol novolac epoxy resins, and alkoxy groups having 1 to 8 carbon atoms And dialkoxybenzene.

Examples of the cationically polymerizable compound (C4) having an alicyclic structure include finger ring epoxy compounds having 7 or more carbon atoms and 1,500 or less number average molecular weight [for example, at least one cyclohexene ring or cyclopentene ring-containing compound is an oxidizing agent. A cyclohexene oxide-containing compound or a cyclopentene oxide-containing compound obtained by epoxidation with a ring], and a finger ring hydrocarbon having an alkoxy group having 1 to 8 carbon atoms [eg, diethoxycyclohexane, di-t-butoxycyclohexane, dioctoxycyclohexane Pentane].
Examples of the alicyclic epoxy compound include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-1-methylcyclohexyl-3,4-epoxy-1-methylhexanecarboxylate. 6-methyl-3,4-epoxycyclohexylmethyl-6-methyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-3-methylcyclohexylmethyl-3,4-epoxy-3-methylcyclohexanecarboxylate 3,4-epoxy-5-methylcyclohexylmethyl-3,4-epoxy-5-methylcyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane Metadioxane, bis (3 -Epoxycyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexylcarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, and ethylenebis (3,4-epoxycyclohexanecarboxylate) Can be mentioned.

  Among these cationically polymerizable compounds (C1) to (C4), from the viewpoints of developability, curability, elastic recovery properties, and adhesion, preferably hexapentaGE of dipentaerythritol, the above general formula (1) The compound (C1) and the compound (C21) represented by the general formula (2), more preferably the compound (C1) and the compound (C21), and particularly preferably the compound (C1).

The content of (C) based on the total weight of (A) to (F) of the photosensitive resin composition (Q) is usually 5 to 60% by weight, preferably 5 to 45% by weight, particularly preferably 10 to 30%. % By weight. Within this range, the elastic recovery characteristics and the adhesion to the substrate can be exhibited well, and the developability can also be exhibited well.

The siloxane compound (D) having two or more hydrolyzable alkoxy groups, which is an essential component of the present invention, has, for example, a silane compound (d1) represented by the following general formula (3) as an essential constituent monomer, Examples include a condensate obtained by polymerizing a part or all of an alkoxy group [OR ¹⁰ part in the general formula (3)] by a condensation reaction. However, it may be a siloxane compound having a hydrolyzable alkoxy group having another chemical structure.

The “hydrolyzable alkoxy group” as used herein is an alkoxy group having 1 to 8 carbon atoms such as methoxy group, ethoxy group, propyloxy group, isopropyloxy group, butyloxy group, sec-butyloxy group, t -A butyloxy group, a pentyloxy group, a heptyloxy group, and an octyloxy group are mentioned.
On the other hand, phenoxy groups generally do not hydrolyze.

In the general formula (3), R ⁸ is selected from the group consisting of a (meth) acryloylalkyl group, a glycidoxyalkyl group, a mercaptoalkyl group, and an aminoalkyl group (the alkyl group has 1 to 6 carbon atoms). One kind of organic group. R ⁹ is an alkyl group having 1 to 12 carbon atoms, an alicyclic saturated hydrocarbon group having 1 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 12 carbon atoms; R ¹⁰ is an alkyl group having 1 to 4 carbon atoms. It is an alkyl group. m is 0 or 1.

R ⁸ in the formula (3) is one organic group selected from the group consisting of a (meth) acryloylalkyl group, a glycidoxyalkyl group, a mercaptoalkyl group, and an aminoalkyl group. Carbon number is 1-6.

Here, the (meth) acryloylalkyl group is represented by the following general formula (4); the glycidoxyalkyl group is represented by the following general formula (5); the mercaptoalkyl group is -R ¹¹ -SH; the aminoalkyl group is -R ¹¹ -NH _2. It is represented by

R ¹² in the formula (4) is a hydrogen atom or a methyl group. —R ¹¹ — is an alkylene group having 1 to 6 carbon atoms.

-R < ¹³ >-in Formula (5) is a C1-C6 alkylene group.

In the general formula (3), specific examples of the silane compound having a (meth) acryloylalkyl group in R ⁸ include the following compounds in which m is 0 or 1.
Examples of the trifunctional silane compound in which m is 0, that is, three alkoxy groups include 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3- Examples include acryloyloxypropyltriethoxysilane.

  Examples of the trifunctional silane compound in which m is 1, that is, two alkoxy groups include 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, 3 -Acryloyloxypropylmethyldiethoxysilane and the like.

Specific examples of the silane compound having a glycidoxyalkyl group in R ⁸ include the following compounds in which m is 0 or 1.
Examples of the trifunctional silane compound in which m is 0, that is, three alkoxy groups include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and the like.

  Examples of the trifunctional silane compound in which m is 1, that is, two alkoxy groups include 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and the like.

Specific examples of the silane compound having a mercaptoalkyl group in R ⁸ include the following compounds in which m is 0 or 1.
Examples of the trifunctional silane compound in which m is 0, that is, three alkoxy groups include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and the like.

  Examples of the trifunctional silane compound in which m is 1, that is, two alkoxy groups include 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, and the like.

Specific examples of the silane compound having an aminoalkyl group in R ⁸ include the following compounds in which m is 0 or 1.
Examples of trifunctional silane compounds in which m is 0, that is, three alkoxy groups include N-2 aminoethyl γ-aminopropyltrimethoxysilane, N-2 aminoethyl γ-aminopropyltriethoxysilane, and 3-aminopropyltrimethoxy. Silane, 3-aminopropyltriethoxysilane, etc. are mentioned.

  Examples of trifunctional silane compounds in which m is 1, that is, two alkoxy groups include N-2 aminoethyl γ-aminopropylmethyldimethoxysilane, N-2 aminoethyl γ-aminopropylmethyldiethoxysilane, and 3-aminopropylmethyl. Examples include dimethoxysilane and 3-aminopropylmethyldiethoxysilane.

R ⁸ does not react in the condensation reaction step of the silane compound (d1) and remains in the siloxane compound (D) after the condensation reaction, and the photosensitive resin composition of the present invention is exposed to light or thermally cured. It is a functional group that contributes to the curing reaction.
Preferred as R ⁸ are a (meth) acryloylalkyl group and a glycidoxyalkyl group from the viewpoint of curability.

R ⁹ in Formula (3) represents a C 1-12 alkyl group, a C 1-12 alicyclic saturated hydrocarbon group, or a C 6-12 aromatic hydrocarbon group. The number m is 0 or 1.

Among R ⁹ , examples of the aliphatic saturated hydrocarbon group include a linear alkyl group and a branched alkyl group.
Examples of the linear alkyl group include methyl, ethyl, n-propyl, n-butyl, n-octyl and n-dodecyl groups. Examples of the branched alkyl group include isopropyl, isobutyl, sec-butyl and 2-ethylhexyl groups. Can be mentioned.

Examples of the alicyclic saturated hydrocarbon group include a cyclohexyl group, a cyclooctyl group, a cyclohexylmethyl group, a cyclohexylethyl group, and a methylcyclohexyl group.

Among R ⁹ , 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 ⁹ is preferably a linear alkyl group, a branched alkyl group or an aryl group from the viewpoint of curing reactivity, and more preferably a linear alkyl group or an aryl group. Particularly preferred are a methyl group, an ethyl group, a phenyl group and a combination thereof.

Examples of R ¹⁰ in the formula (3) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and a sec-butyl group. Preferred is methyl from the viewpoint of thermosetting reactivity. Group and ethyl group.
The number of OR ¹⁰ groups bonded to the Si atom is (3-m), specifically, 3 or 2.

Among the silane compounds (d1) represented by the general formula (3), R ⁸ in the general formula (3) preferably has a (meth) acryloylalkyl group or a glycidoxyalkyl group from the viewpoint of curing reactivity. Silane compound.
More preferred are (meth) acryloyloxyalkyl group-containing trifunctional silane compounds having 3 alkoxy groups, and glycidoxyalkyl group-containing trifunctional silane compounds having 3 alkoxy groups, and particularly preferred are 3-acryloyloxypropyltrimethoxysilane and 3-glycidoxypropyltrimethoxysilane.

  Examples of the siloxane compound (D) having two or more hydrolyzable alkoxy groups include a homocondensation polymer composed only of the silane compound (d1) represented by the general formula (3), and (d1) and (d1) Examples thereof include cocondensates of one or more other silane compounds capable of cocondensation.

Examples of such other silane compounds include silane compounds represented by the following general formula (6).

R ¹⁴ _n Si (OR ¹⁵ ) _4-n (6)

In the formula (6), R ¹⁴ is an alkyl group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, R ¹⁵ is an alkyl group having 1 to 4 carbon atoms, and n is 0 to 0. It is an integer of 2.

Among R ^14, 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 ¹⁵ is preferably a methyl group or an ethyl group.

In the general formula (6), n is 0, that is, examples of the tetrafunctional silane compound having 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 (D).

  From the viewpoint of curing reactivity, the charging ratio of the other silane compound is preferably 0.1 to 6.0 mol, more preferably 0.2 to 4 with respect to 1 mol of (d1). 0.0 mole is good.

  The siloxane compound (D) is, for example, about 10 to 20 ° C. at 20 to 100 ° C. in a dry atmosphere with stirring a predetermined amount of water and, if necessary, a catalyst in the silane compound (d1) and other silane compounds used as necessary. It can be obtained by performing a condensation reaction by dropping over a period of 60 minutes to 60 minutes and then aging for 1 to 12 hours at a temperature below the boiling point of the by-produced alcohol (for example, 0 to 150 ° C.).

If 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 other silane compounds is Y, the yield and molecular weight of the condensate will decrease if X / Y is too small. To do. 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 inorganic acids, 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 100 parts by weight as the total of the silane compound (d1) and the other silane compounds. 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.

The siloxane compound (D) of the present invention preferably has an absolute value of the difference in SP value from the above-mentioned polyfunctional (meth) acrylate monomer (A) having an acidic group from the viewpoint of compatibility and the elastic recovery properties of the cured product. Is 2.0 or less, more preferably 1.9 or less, particularly preferably 1.5 or less, and particularly preferably 1.0 or less.

The SP value of the siloxane compound (D) is preferably 7.0 to 13.0, more preferably 8.0 to 12.0, particularly preferably 8.0 to 11.0, and particularly preferably 8.0. ~ 10.5.

The content of (D) based on the total weight of (A) to (F) of the photosensitive resin composition (Q) is usually preferably 1 to 40% by weight, more preferably 1 to 30% by weight, particularly preferably. 5 to 30% by weight. Within this range, the elastic recovery property and the adhesion to the substrate can be exhibited more satisfactorily, and the compatibility can also be exhibited better.

Mn of the siloxane compound (D) is preferably from 500 to 100,000, more preferably from 1,000 to 50,000, particularly preferably from the viewpoint of elastic recovery characteristics when it becomes a photospacer and adhesion to the substrate. Is 2,000 to 20,000.

The photo radical polymerization initiator (E) is composed of a component that generates a radical capable of initiating polymerization of the polymerizable unsaturated compound by exposure to radiation such as visible light, ultraviolet light, far infrared light, charged particle beam, and X-ray.
Examples of such photo radical polymerization initiators include acetophenone derivatives (E1), acylphosphine oxide derivatives (E2), titanocene derivatives (E3), triazine derivatives (E4), bisimidazole derivatives (E5), O-acyloxys. A oxime ester derivative (E6), a benzophenone derivative (E7), a thioxanthone derivative (E8), an α-diketone derivative (E9), an anthraquinone derivative (E10), an acridine derivative (E11), and two or more of these A mixture is mentioned.

Examples of the acetophenone derivative (E1) include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, benzyldimethyl ketal, 2-hydroxy-2-methylpropiophenone, 4-isopropyl-2-hydroxy-2-methylpropiophenone, 2 -Methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone, dimethylbenzyl ketal, methylbenzoylformate, 2-benzyl-2-dimethylamino-1- (4-morpholino Eniru) - butan-1-one] and the like.

Examples of the acylphosphine oxide derivative (E2) include trimethylbenzoyl diphenylphosphine oxide.

Examples of the titanocene derivative (E3) include bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium. .

Examples of the triazine derivative (E4) include trichloromethyltriazine and benzyl-2,4,6- (trihalomethyl) triazine.

Examples of the bisimidazole derivative (E5) include 2- (o-chlorophenyl) -4,5-diphenylimidazolyl dimer.

Examples of the O-acyloxime (oxime ester) derivative (E6) include 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], ethanone, 1- [9. -Ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime).

Examples of the benzophenone derivative (E7) include benzophenone, 4,4-bis (dimethylamino) benzophenone, 3,3-dimethyl-4-methoxy-benzophenone, and Michler's ketone.

Examples of the thioxanthone derivative (E8) include isopropylthioxanthone, 2-chlorothioxanthone, diethylthioxanthone, isopropylthioxanthone, and diisopropylthioxanthone.

Examples of the α-diketone derivative (E9) include camphorquinone.

Examples of the anthraquinone derivative (E10) include anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, and tert-butylanthraquinone.

Examples of the acridine derivative (E11) include 9-phenylacridine, 1,7-bis (9-acridinyl) heptane, 1,5-bis (9-acridinyl) pentane, and 1,3-bis (9-acridinyl) propane. Can be mentioned.

  Of these (E1) to (E11), from the viewpoint of ease of synthesis, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone and 2-benzyl-2-dimethylamino -1- (4-morpholinophenyl) -butan-1-one is preferred, and 2-methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone is more preferred from the viewpoint of reactivity.

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

The content of the photo radical polymerization initiator (E) based on the total weight of (A) to (F) of the photosensitive resin composition (Q) is preferably 1 to 15% by weight, more preferably 3 to 12% by weight. Particularly preferably, it is 5 to 10% by weight. If it is 1% by weight or more, curing reactivity and elastic recovery characteristics can be exhibited more satisfactorily, and if it is 15% by weight or less, mask stain reduction and compatibility during photoexposure can be further exhibited.

  In the present invention, the acid generator (F) contained as an essential component in the photosensitive resin composition (Q) is not particularly limited as long as it is a compound that generates heat by absorbing heat or light energy. Can do. Examples of the acid generator (E) include the following sulfone compound (F1), sulfonic acid ester compound (F2), sulfonimide compound (F3), disulfonyldiazomethane (F4), and onium salt (F5). It is done.

Examples of the sulfone compound (F1) include phenacylphenylsulfone, 4-trisphenacylsulfone-ketosulfone, β-sulfonylsulfone, and α-diazo compounds thereof.

Examples of the sulfonic acid ester compound (F2) include benzoin tosylate, pyrogallol tris trifluoromethane sulfonate, pyrogallol methane sulfonic acid triester, α-methylol benzoin tosylate and α-methylol benzoindodecyl sulfonate.

Examples of the sulfonimide compound (F3) include N- (trifluoromethylsulfonyloxy) succinimide, N- (p-toluenesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide. N- (perfluorooctanesulfonyloxy) naphthylimide, N- (benzenesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (benzenesulfonyloxy) bicyclo [2.2.1] heptane-5,6-oxy-2,3-dicarboximide, N- (benzenesulfonyloxy) naphthylimide and the like.

Examples of the disulfonyldiazomethane compound (F4) include 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] decan-7-sulfonyl) diazomethane.

Examples of the onium salt (F5) include sulfonium salts [bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluorophosphate, allylsulfonium hexafluorophosphate, hexafluoroantimonate, etc.], iodonium salts (diphenyliodonium hexafluorophosphate, etc.) ), Phosphonium salts (such as ethyltriphenylphosphonium tetrafluoroborate), diazonium salts (such as phenyldiazonium hexafluorophosphate), ammonium salts (such as 1-benzyl-2-cyanopyridinium hexafluorophosphate), and ferrocene [(2,4 -Cyclopentadien-1-yl) [(1-methylethyl) benzene] -Fe (II) hexafluorophosphate, etc.].

  Of these acid generators (F1) to (F5), from the viewpoint of storage stability and low temperature reactivity, the sulfonimide compound (F3), the disulfonyldiazomethane compound (F4), and the onium salt (F5) are preferable. -(Trifluoromethylsulfonyloxy) succinimide, bis (phenylsulfonyl) diazomethane, and a sulfonium salt of hexafluoroantimonate are more preferred, and a sulfonium salt of hexafluoroantimonate is particularly preferred.

The content of (F) based on the total weight of (A) to (F) of the photosensitive resin composition (Q) is usually 0.5 to 15% by weight, preferably 1 to 10% by weight, particularly preferably 2 ~ 5% by weight. If it is 10% by weight or less, the compatibility can be further improved.

Furthermore, when the acid value of the photosensitive resin composition (Q) is in a specific range, the developability and the water resistance of the cured product of the photosensitive resin composition (Q) can be further improved.
That is, the acid value based on the total weight of the photosensitive resin composition (A) to (F) is usually 10 to 110 KOHmg / g, preferably 25 to 90 KOHmg / g, more preferably 40 to 80 KOHmg / g, particularly preferably. 50-75 KOH mg / g. Within this range, the developability is more easily exhibited, and the water resistance of the cured product can be further improved.

Furthermore, the higher the content (mmol / g) of the carbon-carbon double bond (C = C) in the (meth) acryloyl group of the photosensitive resin composition (Q), the higher the photosensitive resin composition (Q). The elastic recovery characteristics of the cured product can be further improved.
That is, the content (mmol / g) of the carbon-carbon double bond (C = C) in the (meth) acryloyl group based on the total weight of the photosensitive resin composition (A) to (F) is usually 6 0.5 to 10.0 mmol / g, preferably 7.0 to 10.0 mmol / g, more preferably 7.5 to 9.5 mmol / g, and particularly preferably 8.0 to 9.5 mmol / g. . Within this range, the elastic recovery characteristics can be satisfactorily exhibited.

Here, the content (mmol / g) of the carbon-carbon double bond in the (meth) acryloyl group in the present invention refers to the acryloyl group or methacryloyl group in the photosensitive resin composition (Q) of the present invention. This refers to the content (mmol / g) of the resulting carbon-carbon double bond (C = C).

The concentration of the double bond can be measured by a titration method using an addition reaction (Michael addition) of an amine to a double bond of a (meth) acryloyl group.
The specific measurement method is as follows.

(1) About 1 g of a sample is precisely weighed and placed in an Erlenmeyer flask, and then about 10 ml of acetone is added and dissolved.
(2) Add 10 ml of morpholine standard solution [mixed formolin and methanol 1: 4 (volume ratio)], and then add 50% acetic acid standard solution [acetic acid and ion-exchanged water 1: 1 (volume ratio) After adding 1.5 ml and shaking well, leave it at room temperature for 15 minutes.
(3) Add 15 ml of acetonitrile and 10 ml of acetic anhydride to the Erlenmeyer flask and shake well.
(4) Titrate with a 0.5 mol / L acetic acid / methanol titration solution using a recording type automatic titrator.
(5) A blank test is performed at the same time, and the following formula is used.

Double bond concentration (mmol / g) = f × (A−B) / 2S
However, A is the number of ml of 0.5 mol / L acetic acid / methanol titration solution required for the titration of the sample, B is the number of ml of 0.5 mol / L acetic acid / methanol titration solution required for the blank test, f Represents the titer of a 0.5 mol / L acetic acid / methanol titration solution, and S represents the sample collection amount (g) [when the sample contains a solvent, the amount excluding the solvent (g)].

Furthermore, the higher the hydroxyl group concentration in the photosensitive resin composition (Q), the better the adhesion between the cured product of the photosensitive resin composition (Q) and the substrate.
From the viewpoint of improving adhesion, the hydroxyl group concentration based on the total weight of (A) to (F) of the photosensitive resin composition is preferably 1.5 to 5.0 mmol / g, and 2.0 to 5.0 mmol / g. Is more preferable, and 2.5 to 5.0 mmol / g is particularly preferable. Within this range, the adhesion and water resistance between the cured product of the photosensitive resin composition (Q) and the substrate can be further improved.

The hydroxyl group concentration (mmol / g) refers to the hydroxyl group content (mmol / g) in the photosensitive resin composition (Q) of the present invention.
Examples of the hydroxyl group include alcoholic hydroxyl groups, phenolic hydroxyl groups, hydroxyl groups in carboxyl groups, hydroxyl groups in sulfonic acid groups, hydroxyl groups in phosphoric acid groups, and the like. Of these hydroxyl groups, an alcoholic hydroxyl group and a hydroxyl group within a carboxyl group are preferred, and an alcoholic hydroxyl group is more preferred.

This hydroxyl group concentration can be measured by calculating from the hydroxyl value obtained by the phthalic anhydride method (based on JIS K1557) utilizing a dehydration condensation reaction between a hydroxyl group and phthalic anhydride.
The specific measurement method is as follows.

(I) About 1 g of a sample is precisely weighed and placed in an Erlenmeyer flask, and dissolved in 5 ml of an acetylating agent [mixture of phthalic anhydride and pyridine at 1: 4 (volume ratio)].
(Ii) Heat at 100 ° C. for 2 hours, add 1 ml of water, vibrate well, and leave at room temperature for 10 minutes.
(Iii) Titration is performed using phenolphthalein as an indicator and KOH aqueous solution (0.5 mol / L) as a titrant.
(Iv) The acid value is measured for the same sample.
(V) A blank test is performed at the same time, and the hydroxyl value is calculated by the following formula.
Hydroxyl value (KOHmg / g) = (BA) × f × 28.05 / S + C
However, A is the number of ml of the 0.5 mol / L potassium hydroxide titration solution required for the titration of the sample, B is the number of ml of the 0.5 mol / L potassium hydroxide titration solution required for the blank test, f Is the force value of the 0.5 mol / L potassium hydroxide titration solution, S is the amount of sample collected (g [amount excluding the solvent (g) if the sample contains a solvent)], C is the acid value [the measurement method is As described above].
(Vi) Using the hydroxyl value obtained by the above equation, the hydroxyl group concentration is calculated by the following equation.
Hydroxyl concentration (mmol / g) = hydroxyl value / 56.1

The photosensitive resin composition (Q) may further contain other components as necessary.
Other components include inorganic fine particles, sensitizers, polymerization inhibitors, solvents, thickeners, surface conditioners, and other additives (eg, inorganic pigments, silane coupling agents, dyes, fluorescent brighteners, Yellowing inhibitors, antioxidants, antifoaming agents, deodorants, fragrances, bactericides, antibacterial agents, fungicides, etc.).

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.

  The photosensitive resin composition (Q) of the present invention has good alkali developability, is excellent in the elastic recovery characteristics of the cured product and the adhesion to the substrate, and is subjected to a post-bake treatment at a temperature of 200 ° C. or lower, which is lower than usual. Even when it is adopted, the cured product is excellent in the elastic recovery characteristics and the adhesion to the substrate, and is particularly suitable as a photosensitive resin composition for a photospacer provided for maintaining a gap in a liquid crystal cell.

In general, the elastic recovery characteristic of a photospacer can be evaluated by the “elastic recovery rate” when a certain pressure is applied, and the higher the elastic recovery rate, the better the elastic recovery characteristic.
And the elastic recovery rate becomes small, so that pressurization is large.

By the way, when a conventionally known photosensitive resin composition is cured by light irradiation and a post-bake treatment is employed at a temperature higher than 200 ° C., for example, 230 ° C., 0.3 mN / μm ^{2 of the} formed photo spacer. The elastic recovery rate under the pressure condition is usually about 70%.
However, when the pressure condition is increased to 0.5 mN / μm ² , the elastic recovery rate is greatly reduced.
Furthermore, when post-baking is employed at 200 ° C. or lower, for example, 150 ° C., only a recovery elastic modulus of about 30% can be obtained under a pressure condition of 0.5 mN / μm ² .

However, the photosensitive resin composition (Q) of the present invention is 0.5 mN / μm of the formed photo spacer even when the photosensitive resin composition is cured by light irradiation and a low temperature treatment of 200 ° C. or less is adopted. The elastic recovery rate under the pressure condition of ² is usually 50% to 100%, preferably 60 to 100%, more preferably 70 to 100%, and particularly preferably 80 to 100%.
When the elastic recovery rate is 70% or more, the elastic recovery characteristic can be further improved, and there is a high possibility that it can be used practically without any problem as a spacer for holding the liquid crystal cell gap. When it is 45% or less, the adhesion is further improved, but the elastic recovery characteristic is low, and there is a high possibility that it will be a practical problem that the liquid crystal cell gap cannot be maintained.

The photo spacer of the present invention will be described below.
The photospacer of the present invention is a photospacer that is formed by curing the photosensitive resin composition (Q) and is provided for maintaining a gap in the liquid crystal cell.
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 height of the photo spacer usually 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.

The preferable formation process of the photospacer of the present invention is a process in which a photosensitive resin composition is applied onto a substrate, irradiated with light, subjected to alkali development to form a pattern, and further post-baked.
The formation of the photo spacer is usually performed in the following steps (1) to (5).

(1) The process of apply | coating the photosensitive resin composition of this invention on the transparent common electrode provided on the colored layer of a board | substrate. Examples of the coating method include roll coating, spin coating, spray coating, and slit coating. Examples of the coating apparatus include spin coater, air knife coater, roll coater, bar coater, curtain coater, gravure coater, and comma coater. It is done.
The film thickness is usually 0.5 to 10 μm, preferably 1 to 5 μm.

(2) A step of drying (prebaking) the applied photosensitive resin composition layer by applying heat as necessary. The drying temperature is preferably 10 to 120 ° C, more preferably 12 to 90 ° C, particularly 15 to 60 ° C, particularly 20 to 50 ° C. The drying time is preferably 0.5 to 10 minutes, more preferably 1 to 8 minutes, and particularly preferably 2 to 5 minutes. 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.

(3) A step of exposing the photosensitive resin composition layer with actinic rays through a predetermined photomask. If the photosensitive resin composition of the present invention, even in mask openings having a diameter of about 4 to 10 [mu] m ⁽² about area 12～100Myuemu), accurately, i.e. the diameter 5~12μm of (area 20 to 120 ²⁾ A pattern can be formed in a range.
Examples of the active light 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.
The exposure amount is not particularly limited, preferably 20~300mJ / cm ^2, more preferably 20~100mJ / cm ² from the viewpoint of production cost, 20~60mJ / cm ² is particularly preferred. In the step of performing exposure light, a component having a (meth) acryloyl group in the photosensitive resin composition reacts to undergo photocuring reaction.

(4) A step of developing after removing the unexposed portion with a developer after light irradiation. As the developer, an alkaline aqueous solution is usually used. Examples of the alkaline aqueous solution include aqueous solutions of alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; aqueous solutions of carbonates such as sodium carbonate, potassium carbonate and sodium hydrogencarbonate; hydroxytetramethylammonium and hydroxytetraethylammonium. And an aqueous solution of an organic alkali. 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.

(5) Post-heating (post-baking) step. The post-baking temperature is 50 to 280 ° C, preferably 100 to 250 ° C, more preferably 120 to 240 ° C, and particularly preferably 140 to 230 ° C.
The post-bake time is 5 minutes to 2 hours.

Post bake 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.
By performing post-baking, the elastic recovery characteristics of the photo spacer are further improved.
In this post-heating (post-baking) step, it is presumed that the component having a thermosetting functional group in the photosensitive resin composition reacts and thermosets. Examples of the thermosetting functional group include the hydrolyzable alkoxy group in (C) or (D) and the (meth) acryloyl group in (A), (B) or (D). The trace amount (meth) acryloyl group which remained in the exposure process of this is mentioned.

Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Hereinafter, unless otherwise specified, “%” represents “% by weight” and “parts” represents “parts by weight”.

Production Example 1 [Production of hydrophilic epoxy resin solution (A-1)]
Glass Kolben equipped with heating / cooling / stirring measures, reflux condenser, dropping funnel and nitrogen inlet, cresol novolac epoxy resin “EOCN-102S” (Epoxy equivalent 200, Nippon Kayaku Co., Ltd.) and propylene 245 parts of glycol monomethyl ether acetate was charged and heated to 110 ° C. to dissolve uniformly. Subsequently, 76 parts of acrylic acid (1.07 mol part), 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 and further reacted at 90 ° C. for 5 hours. After that, propylene glycol monomethyl ether acetate was added, and the content of hydrophilic epoxy resin was 50%. Was diluted to obtain a 50% solution (A-1) of a hydrophilic epoxy resin having an acryloyl group and a carboxyl group.
In addition, it was number average molecular weight (Mn) by GPC as resin solid content conversion: 2,200, SP value: 11.3, HLB value: 6.4, and acid value: 91 mgKOH / g.

Production Example 2 [Production of acrylate-modified polysiloxane (D-1)]
In a glass Kolben equipped with a heating / cooling / stirring measure, a reflux condenser, a dropping funnel and a nitrogen introduction pipe, 46 parts (0.2 mole part) 3-acryloyloxypropyltrimethoxysilane, 160 parts diphenyldimethoxysilane (0 .65 mol parts), 45 g (2.5 mol parts) of ion-exchanged water, and 0.1 part (0.001 mol parts) of oxalic acid, and heated and stirred at 60 ° C. for 6 hours. The methanol produced as a by-product by hydrolysis was removed under reduced pressure of 6.7 kPa over 2 hours to obtain acrylate-modified polysiloxane (D-1) (Mn: 2,100).

Production Example 3 [Production of Acid Generator Solution (F-2)]
A 50 wt% propylene carbonate solution (F-2) of 4- (phenylthio) phenyldiphenylsulfonium tris (pentafluoroethyl) trifluorophosphate was synthesized according to the method described in Examples of the pamphlet of International Publication No. 05/116038.

Comparative Production Example 1 [Production of methacrylic acid copolymer solution (G-1) blended in Comparative Example 5]
According to the method described in Synthesis Example 1 of JP-A-2009-75284, methacrylic acid, tricyclodecan-8-yl methacrylate, styrene, butadiene and glycidyl methacrylate are reacted to produce these methacrylic acid copolymers. A 30% by weight diethylene glycol methyl ethyl ether solution (G-1) was synthesized.

Comparative Production Example 2 [Production of methacrylic acid copolymer solution (G-2) blended in Comparative Example 6]
According to the method described in Example 1 of JP2009-186838A, 30% by weight of these methacrylic acid-based copolymers from methacrylic acid, dimethylbutyrolactone acrylate and glycidyl methacrylate / 1-methoxy-2-propanol / 1 A methoxy-2-propyl acetate solution (G-2) was synthesized.

[Production of photosensitive resin composition]
Examples 1-8 and Comparative Examples 1-6
In accordance with the number of parts in Table 1 and Table 2, each component is charged into a glass container, stirred until uniform, and further diluted with propylene glycol monomethyl ether acetate so that the active ingredient concentration is 35%. The photosensitive resin composition of Examples 1-8 of this invention and the photosensitive resin composition of Comparative Examples 1-6 were obtained.

The symbols in Tables 1 and 2 are as follows.
(B-1): Multifunctional (meth) acrylate: “NK ester A-TMM-3Lnew” (pentaerythritol triacrylate: manufactured by Shin-Nakamura Chemical Co., Ltd.)
(B-2): Multifunctional (meth) acrylate: “DA-600” (mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate: manufactured by Sanyo Chemical Industries, Ltd.)
(B-3): Multifunctional (meth) acrylate: “DPCA-120” (Caprolactone-modified dipentaerythritol hexaacrylate: Nippon Kayaku Co., Ltd.)
(B-4): Multifunctional (meth) acrylate: “Aronix M-520” (manufactured by Toagosei Co., Ltd.)
(C-1) Cationic polymerizable compound: “Cymel 303” (Mitsui Cytec Co., Ltd.)
(C-2) Cationic polymerizable compound: “Denacol EX-411” (pentaerythritol polyglycidyl ether: manufactured by Nagase ChemteX Corporation)
(E-1): Photoradical polymerization initiator: “Irgacure 907” (2-methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone: manufactured by Ciba Specialty Chemicals Co., Ltd. )
(E-2): Photoradical polymerization initiator: “Irgacure OX02” (ethanone, 1- (9-ethyl-6- (2-methylbenzoyl) -9, H, -carbazol-3-yl)-, 1- (O-acetyloxime): Ciba Specialty Chemicals Co., Ltd.)
(E-3): Photoradical polymerization initiator: “Irgacure 379” (2-dimethylamino-2- (4-methyl-benzyl) -1- (4-morpholin-4-yl-phenyl) -butane-1 -ON: Ciba Specialty Chemicals Co., Ltd.)
(E-4): Photoradical polymerization initiator: “CGI242” (1- (9- (2-methylbenzoyl) -9, H, -carbazol-3-yl) -1- (9- (2-methylbenzoyl) ) -9, H, -carbazol-3-yl) -ethanone, 1- (O-acetyloxime): Ciba Specialty Chemicals Co., Ltd.)
(F-1) Acid generator: "San-Aid SI-150L" (aromatic sulfonium SbF ₆ ^- salt: Sanshin Chemical Industry Co., Ltd.)

About the photosensitive resin composition of Examples 1-8 of this invention, and the photosensitive resin composition of Comparative Examples 1-5, it is a method which shows alkali developability, adhesiveness with a board | substrate, an elastic recovery characteristic, and the resolution below. Measured and evaluated. The results are shown in Tables 1 and 2.

[Evaluation of alkali developability]
The photosensitive resin composition was spin-coated on a glass substrate so that the finished film thickness was 5 μm, and dried at 80 ° C. for 3 minutes. Light from a high-pressure mercury lamp was irradiated at 60 mJ / cm ² through a photomask having a pattern having many openings with a diameter of 6 to 20 μm. Note that the exposure (gap) between the photomask and the substrate was 100 μm.
Thereafter, shower development was performed for 30 seconds using a 1% sodium carbonate aqueous solution. After washing with water, post-baking was performed at 230 ° C. for 30 minutes to form a large number of photo spacers on the substrate.

Depending on the amount of residue (gel, solid such as oligomers and monomers remaining in 1% sodium carbonate aqueous solution) on the surface of these glass substrates on which photo spacers have been formed, developability is determined according to the following criteria. evaluated.
The substrate obtained by the above operation was photographed, and the residue on the substrate was quantitatively confirmed by image data processing. Judgment criteria are as follows.

◎: No residue on substrate ○: Residue on substrate is recognized but less than 5% Δ: Area of residue on substrate covering substrate is less than 5% to less than 75% ×: Substrate of residue on substrate 75% or more area covering

[Production of photo spacer]
The photosensitive resin composition was spin-coated on a glass substrate so that the finished film thickness was 5 μm, and dried at 80 ° C. for 3 minutes. Light from a high-pressure mercury lamp was irradiated at 60 mJ / cm ² through a photomask having a pattern having openings with a diameter of 6 μm to 20 μm. Note that the exposure (gap) between the photomask and the substrate was 100 μm.
Thereafter, shower development was performed for 60 seconds using a 1% aqueous sodium carbonate solution. After washing with water, post-baking was performed at 230 ° C. for 30 minutes to form a large number of photo spacers on the substrate.
In addition, since the comparative example 1 had poor alkali developability and a spacer could not be formed, the post-baking process was not performed, and the following evaluation was not performed.

In addition to the above photo spacers, the post-baking temperature was changed to 200 ° C., 150 ° C., 100 ° C., and 50 ° C., respectively. A large number of photo spacers were formed.

The lower base diameter of the photo spacer is the diameter of the portion where the spacer contacts the substrate, and the upper base diameter of the photo spacer is the diameter at a position 90% of the height of the spacer, respectively. Measurement was performed using a microscope VK-8700 (manufactured by Keyence Corporation).
The lower base diameters of the photo spacers prepared using the photosensitive resin compositions of Examples 1 to 8 and Comparative Examples 1 to 6 are in the range of 7 to 21 μm depending on the size of the mask. The upper base diameter was in the range of 4 to 19 μm.

[Evaluation of adhesion]
With the miniaturization and high definition of LCD, a size of 10 μm or less is required for the size of a photo spacer manufactured on a substrate. However, the smaller the ground contact area between the substrate and the photo spacer, the higher the adhesion is required. That is, a photo spacer having higher adhesion is more excellent in performance of being less likely to be peeled off by rubbing or the like even when the lower bottom diameter of the spacer is reduced. Therefore, the adhesiveness was evaluated by setting the lower bottom diameter of the spacer at two levels of 15 μm and 8 μm, and the following swab rubbing test.

A large number of photo spacers were formed on the substrate in the same manner as the photo spacers described above. Of these spacers, 100 arbitrary spacers were selected for determination with respect to photo spacers having a bottom diameter of 15 μm and 8 μm, respectively.
A cotton swab soaked in acetone was rubbed against the substrate on which the spacers were formed at a speed of 2 cm / second, 10 times in each direction, and then the peeling state of 100 arbitrary spacers existing on the substrate was observed with an optical microscope. Observed and evaluated for adhesion.
Judgment criteria are as follows.
A: No. of peeled spacers 0: No. of peeled spacers 1 to 3 Δ: No. of peeled spacers 4 to 89 x: No. of peeled spacers 90 to 100

[Resolution evaluation]
As the size and resolution of LCDs have been reduced and the pixel size has been reduced, patterning with a resolution of 10 μm or less has been required as a resolution. That is, the higher the resolution, the better the performance of forming a spacer having the same size as the remaining mask pattern even if the remaining mask pattern is smaller.
Therefore, the resolution was evaluated by setting the remaining pattern of the mask to a diameter of 10 μm and performing the following test.

A large number of photospacers were formed on a substrate in the same manner as in the production of the photospacer except that a photomask having a pattern having an opening having a diameter of 10 μm was used as the photomask. The lower base diameter of the photo spacer was measured with a laser microscope, and this was used as an evaluation of resolution. It can be said that the smaller the bottom diameter, the higher the resolution.

Criteria based on the lower base diameter of the spacer are as follows. The results are shown in Tables 1 and 2.
○: Less than 11 μm Δ: 11-13 μm
×: 13 μm or more

[Evaluation of elastic recovery characteristics]
The elastic recovery characteristic of the photo spacer can be evaluated by the “elastic recovery rate” when a certain pressure is applied. The higher the elastic recovery rate (%), the better the elastic recovery characteristics.
Further, when the pressure applied to the photospacer is large, the higher the elastic recovery rate, the better the elastic recovery characteristic.
In the present invention, the elastic recovery properties can be the following method is assessed by measuring the elastic recovery at pressure conditions of 2 levels of 0.3 mN / [mu] m ² and 0.5 mN / [mu] m ^2.

The photospacer obtained as described above was subjected to a constant load at 25 ° C. by using a Fischerscope H-100 (Fischer Instruments) hardness meter and a square indenter (50 μm × 50 μm) in cross section. speed (if pressure is ^{0.3mN / μm 2 0.010mN / μm 2} · sec, when the pressure of ^{0.5mN / μm 2 0.017mN / μm 2} · second), to a predetermined pressure over 30 seconds under pressure was maintained for 5 seconds, a constant unloading speed (if the pressure of ^{0.3mN / μm 2 0.010mN / μm 2} · sec, when the pressure of 0.5mN / μm ² 0.017mN / μm pressure over 30 seconds ² · sec) was unloading to 0, determine the total deformation amount T _{0 ([mu]} m) from the hysteresis curve of the load and the spacer deformation amount when held for 5 seconds, further plastic deformation T ([Mu] m) and asked to calculate elastic recovery at a given pressure (%) by the following equation.

Elastic recovery rate (%) = [(T ₀ −T ₁ ) / T ₀ ] × 100
As a pressure, a hysteresis curve was measured at a pressure of 0.3 mN / μm ² or 0.5 mN / μm ² , an elastic recovery rate was calculated, and an elastic recovery characteristic was evaluated.
The criteria for determining the elastic recovery rate are as follows.
A: 80% or more B: 70-80%
Δ: 60-70%
X: Less than 60%

As shown in Examples 1 to 8, the photosensitive resin composition for a photospacer of the present invention is excellent in all aspects of alkali developability, exposure sensitivity, resolution, adhesion to a substrate, and elastic recovery characteristics. Further, even when a low temperature treatment of 200 ° C. or lower is adopted after curing by light irradiation, the photospacer obtained by the present invention has excellent adhesion to the substrate and excellent elastic recovery characteristics.
On the other hand, in Comparative Example 1 in which the photosensitive resin composition does not use the hydrophilic epoxy resin, which is an essential component of this patent, the development residue is large and the spacer cannot be formed.
Further, in Comparative Example 2 in which the polyfunctional (meth) acrylate monomer as an essential component of the present invention is not used, the elastic recovery characteristic is low, which is not satisfactory. In Comparative Example 3 in which the cationically polymerizable compound as an essential component of the present invention is not used, the adhesion to the substrate and the elastic recovery properties are low, which is not satisfactory. In Comparative Example 4 in which the polysiloxane compound which is an essential component of the present invention is not used, the adhesion to the substrate and the elastic recovery characteristics are low, which is not satisfactory. Further, in Comparative Examples 5 and 6 in which a polyfunctional (meth) acrylate monomer is used but the hydrophilic epoxy resin, the cationic polymerizable compound and the siloxane compound which are essential components of the present invention are not used, adhesion to the substrate and elastic recovery are obtained. The characteristics are low and not satisfactory. Moreover, when all of Comparative Examples 1-6 employ | adopt a low temperature process, sufficient adhesiveness with a board | substrate and an elastic recovery characteristic are inadequate.

Since the photosensitive resin composition for photospacers of the present invention is excellent in alkali developability, exposure sensitivity, resolution, adhesion to a substrate, and elastic recovery characteristics, it is an overcoat agent for color filters, and other resist materials. For example, it is also useful as a photosensitive resin composition for uses such as a photo solder resist, a photosensitive resist film, a photo adhesive, or a hard coat agent.
Furthermore, even when low-temperature treatment is adopted, it has excellent adhesion to the substrate and elastic recovery characteristics, so it can be used as an overcoat agent for flexible displays, partition walls for organic EL elements, photosensitive insulating films for organic EL elements, organic It is also useful as a photosensitive resin composition for uses such as an overcoat agent for a moisture-proof barrier film of an EL element.

Claims (5)

  Two hydrophilic epoxy resins (A) having one or more (meth) acryloyl groups and one or more carboxyl groups in the molecule, polyfunctional (meth) acrylate monomers (B), two epoxy groups and / or alkoxy groups The essential components are a cationically polymerizable compound (C) having the above in the molecule, a siloxane compound (D) having two or more hydrolyzable alkoxy groups, a radical photopolymerization initiator (E), and an acid generator (F). A negative photosensitive resin composition that can be developed as an alkali, and is characterized by having an elastic recovery rate of 50% or more of a photo spacer formed by post-baking a cured product by light irradiation at 200 ° C. or lower. A photosensitive resin composition (Q) for a photospacer.   The photosensitive resin composition (Q) according to claim 1, wherein the siloxane compound (D) further contains a (meth) acryloyl group. The cationic polymerizable compound (C) is selected from the group consisting of a cationic polymerizable compound (C1) represented by the following general formula (1) and a cationic polymerizable compound (C21) represented by the general formula (2) The photosensitive resin composition (Q) according to claim 1 or 2, wherein the photosensitive resin composition (Q) is at least one species.

[R ^{1 to} R ⁶ each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a glycidyl group, and the total number of alkyl groups or glycidyl groups is 2 to 6. ]

[A ^{1 to} A ⁴ each independently represents a hydrogen atom or —CH ₂ OR ⁷ . R ⁷ represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a glycidyl group, and R ⁷ in A ^{1 to} A ⁴ may be the same or different. However, among A ^{1 to} A ⁴ , the number of —CH ₂ OR ⁷ is 2 to 4, and among 2 to 4 R ⁷ , the total number of alkyl groups or glycidyl groups is 2 to 4. is there. ]   Based on the total weight of (A) to (F) of the photosensitive resin composition, 10 to 70% by weight of the hydrophilic epoxy resin (A) and 20 to 80 of the polyfunctional (meth) acrylate monomer (B). 5% by weight, 5 to 45% by weight of the cationic polymerizable compound (C), 1 to 30% by weight of the siloxane compound (D), 3 to 12% by weight of the photo radical polymerization initiator, and the acid generator (F ) In an amount of 1 to 10% by weight, respectively.   A photospacer formed by curing the photosensitive resin composition according to claim 1.