JPH04355451A - Photopolymerized composite for color filter - Google Patents

Abstract

PURPOSE:To manufacture a highly definite color filter having satisfactory heat resistant and light resistance with a simple process by containing a specified photopolymerizing compound, a specified photopolymerization initiator and a pigment. CONSTITUTION:A compound represented by the formula I and a photopolymerization initiator represented by the formula IV are contained. In the formula I, X represents the formulae II and III. In the formulae I-III, R1-R3 each represent H or CH3, A represents an aliphatic or cyclic hydrocarbon chain, and n represents 1-20. As the photopolymerization initiator, a compound represented by the formula IV, a photosensitive resin consisting of other photopolymerization initiators as occasion demands, a thioxanthone compound, a pigment, and a photopolymerizing and/or thermally polymerizing compound as occasion demands are contained. The compound represented by the formula I is formed by adding an acrylic acid or a methacrylic acid to a desired novolak type epoxy resin such as phenol novolak type and cresol novolak type.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for color filters. More specifically, the present invention relates to a photopolymerizable composition for color filters with excellent optical properties used in liquid crystal display devices, color separation devices, sensors, and the like.

0002

[Prior Art] Color solid-state image sensors, which are in high demand for use in VTR cameras and color copying machines, and color filters used in color liquid crystal display devices, which are increasingly replacing CRT systems due to the trend toward lighter weight and thinner profiles. is formed by providing fine areas colored in two or more different hues on a solid-state image sensor or a transparent substrate. Such colored thin films have conventionally been produced by dyeing methods and printing methods, and especially when high-definition images are required, dyeing methods are the mainstream method.

[0003] However, color filters based on dyeing methods usually form an image on a substrate using a dyed base material such as natural photosensitive resin such as gelatin, amine-modified polyvinyl alcohol, or amine-modified acrylic resin, and then
It is created by dyeing with dyes such as acid dyes, but since it is necessary to form multiple colors on the same substrate, it is necessary to apply resist dyeing each time the hue changes, and the process is extremely complicated and long. . In addition, the dye used, the light resistance of the resin itself,
Since heat resistance and moisture resistance are generally weak, color filters made using these materials naturally have poor light resistance, heat resistance,
There were reliability problems in terms of moisture resistance.

[0004] Color filters produced by the printing method are thermally cured,
Alternatively, it is created by printing on a substrate using an ink containing pigment dispersed in a photocurable resin, and then curing it with heat or light, but it is difficult to form a high-definition image, and the resulting image There was a problem with the surface smoothness.

[0005] Therefore, as a method to simplify the process, a method has been considered in which the dye is dispersed or dissolved in the resin in advance. For example, in JP-A-1-152449, JP-A-1-254918, JP-A-2-153353, and JP-A-2-804, polyfunctional acrylate monomers and highly sensitive halomethyl-S-triazine photopolymerization initiators are used. proposed a method of dispersing pigments in photosensitive resin to form multiple colored patterns. These methods are clearly simpler than the process of forming a color filter using a dyeing method. Moreover, since the resin system and pigments used have high heat resistance and light resistance, the reliability of the color filter formed therewith is higher than that of a color filter formed by a dyeing method.

However, in these photosensitive resins, radicals generated from the photopolymerization initiator during photocuring are trapped by oxygen, and therefore sufficient photocuring cannot be expected when exposed to air. For this reason, once the photopolymerizable composition has been applied and dried, it is necessary to further form an oxygen barrier film such as PVA thereon, which is insufficient in terms of process simplification. On the other hand, a method with a simple process that does not require an oxygen barrier film is disclosed in JP-A-60-129738 and JP-A-60-1.
It is proposed in No. 29739. This is a colored composition using a PVA/stilbazolium-based photocrosslinkable resin, but since the resin base is PVA, it has low heat resistance and is water soluble, so when applied with a spinner, the boiling point of water is low. Because of its low temperature, it was disadvantageous to apply it to large substrates.

[0007]

[Problems to be Solved by the Invention] When producing a color filter, it is desired to develop a photopolymerizable composition for a color filter that has a simple process, excellent light resistance and heat resistance, and good resolution.

[0008]

[Means for Solving the Problems] As a result of the inventors' earnest efforts to find a method for producing a color filter that uses simple steps as described above, has excellent light resistance and heat resistance, and has good resolution, the present inventors have found that: The inventors have discovered that a specific colored photopolymerizable composition satisfies the above characteristics, leading to the present invention.

[0009] That is, the present invention provides a compound represented by the following formula (1)

00
10]

[C5]

(wherein X is

0012

[C6]

[0013] and

[0014]

[C7]

R1, R2 and R3 each represent H or CH3, A represents an aliphatic or cyclic hydrocarbon chain, and n represents 1-20. ) and a compound represented by the following formula (2) as a photopolymerization initiator

[0016]

[Chemical formula 8]

A photopolymerizable composition for a color filter, characterized in that it contains a photosensitive resin consisting of a photopolymerization initiator, a thioxanthone compound, a pigment, and optionally a photopolymerizable and/or thermally polymerizable compound. thing. (2) The photopolymerizable composition for a color filter according to the above item (1), wherein the photopolymerizable compound is a compound having at least one or more functional ethylenically unsaturated double bond. (3) The photopolymerizable composition for a color filter according to the above item (1), wherein the thermally polymerizable compound is a compound having at least a bifunctional or more functional epoxy group. (4) The photopolymerization composition for a color filter according to the above item (1), further comprising a hexaarylbisimidazole compound and a hydrogen donor as other photopolymerization initiators. (5) The hydrogen donor is an aromatic mercaptan (4)
) photopolymerizable composition for color filters. (6) The photopolymerizable composition for color filters according to the above item (4), wherein the hydrogen donor is an aromatic compound having an amino group. (7) The photopolymerizable composition for a color filter according to the above item (5), wherein the aromatic mercaptan is 2-mercaptobenzothiazole or 2-mercaptobenzoxazole. I will provide a.

The photopolymerizable composition for color filters of the present invention will be explained in more detail. The compound represented by formula (1) is produced by adding acrylic acid or methacrylic acid to a desired novolac type epoxy resin such as a phenol novolac type or a cresol novolak type. The side chain carboxylic acid ester is a dicarboxylic acid ester such as maleic anhydride, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, etc., added to the hydroxyl group formed when acrylic acid or the like is added to an epoxy group. Synthesized by adding acid anhydride. In addition, this resin can be made by changing the molar ratio of the acid anhydride added to the hydroxyl group.
It is possible to obtain the desired acid value.

This variability in acid value is useful in that it is possible to adjust the developability when an image is formed by photocuring with ultraviolet rays through a negative mask and then developed by dissolving the unexposed areas with an alkaline aqueous solution. be. JP-A-1-1 mentioned above
No. 52449, JP-A-1-254918, JP-A-2-
No. 153353 and JP-A No. 2-804 use a copolymer of acrylic acid and acrylic ester as an alkaline aqueous solution-soluble resin that imparts developability. However, this type of resin is a resin that does not interact with light at all, and in order to impart developability, it is necessary to use approximately the same amount as the photopolymerizable resin. In this case, the density of ethylenically unsaturated double bonds involved in photopolymerization in the entire resin decreases, naturally resulting in a decrease in photosensitivity, and the cured portion is not dissolved in an alkaline aqueous developer when exposed to air. was difficult to form.

However, the compound represented by formula (1) according to the present invention has a (meth)acrylate group that participates in photopolymerization and a carboxyl group that imparts developability, so it cannot be developed as described above. It is not necessary to contain a resin that only imparts properties, the density of ethylenically unsaturated double bonds involved in photopolymerization in the entire resin does not decrease, and it is possible to form a photopolymerizable composition with high photosensitivity. It is possible. For this reason, it is possible to form a sufficiently hardened area that will not be dissolved in an alkaline aqueous developer even under the influence of oxygen exposed to the air, eliminating the need to apply an oxygen barrier film such as PVA, and color filters. It has the advantage that the manufacturing process is extremely simple.

In the present invention, it is also possible to use a compound having one or more functional ethylenically unsaturated double bonds. These compounds do not have water-soluble groups, and are used to adjust developability or, in the case of polyfunctional compounds, increase the density of ethylenically unsaturated double bonds involved in photopolymerization in the entire resin. Used for the purpose of sensitization. These compounds are used in an amount of 0.1 to 70% by weight based on the compound represented by formula (1).

Examples of such compounds include photocrosslinkable or photopolymerizable monomers, oligomers, and prepolymers such as ethyl acrylate, butyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, ethylene glycol dimethacrylate, and pentaerythritol trimethacrylate. Esters of acrylic acid or methacrylic acid of monohydric or polyhydric alcohols such as acrylate, pentaerythritol trimethacrylate, and dipentaerythritol hexaacrylate; obtained by condensing polyhydric alcohol with monobasic acid or polybasic acid. Polyester (meth)acrylate obtained by reacting a polyester prepolymer with (meth)acrylic acid; Polyurethane obtained by reacting a polyol group with a compound having two isocyanate groups and then reacting (meth)acrylic acid ( Meth)acrylate; Epoxy (meth)acrylate obtained by reacting epoxy resin and (meth)acrylic acid;

[0023]

[Chemical formula 9]

[0024] Polyester having a group in the main chain; Examples thereof include ordinary photopolymerizable resins such as polymers having a cinnamylidene group in a side chain or terminal.

In the present invention, as a thermally polymerizable compound, a compound having at least a bifunctional or higher epoxy group (hereinafter referred to as an epoxy resin) is a compound having a photopolymerizable carboxyl group of the compound represented by formula (1). Addition reaction is carried out to crosslink between photopolymerized products, increasing crosslinking density and improving heat resistance. Such a thermal polymerization reaction is achieved by irradiating ultraviolet rays through a negative mask and applying the developed image only at a high temperature of 120° C. or higher. Also, since epoxy resin does not participate in the photopolymerization reaction, it should be used at a concentration within a range that does not inhibit sufficient photopolymerization reaction, and should be 0.1 to 40% by weight of the total resin composition, especially in order to obtain sufficient heat resistance. It is desirable to use it in a range of 10% by weight or more.

Specific examples of epoxy resins include bisphenol A type epoxy resin; bisphenol F type epoxy resin; novolac type epoxy resin; polycarboxylic acid glycidyl ester; polyol polyglycidyl ether; aliphatic or alicyclic epoxy resin; amine epoxy resin ; triphenolmethane type epoxy resin; dihydroxybenzene type epoxy resin and the like.

In addition, in the present invention, in order to further increase the crosslinking density in the resin, a photopolymerizable and thermally polymerizable material having an ethylenically unsaturated double bond and an epoxy group simultaneously in the resin skeleton is used. A resin can be used. Specific examples of such resins include bisphenol A type epoxy resin; bisphenol F type epoxy resin; novolak type epoxy resin; polycarboxylic acid glycidyl ester; polyol polyglycidyl ether; aliphatic or alicyclic epoxy resin; amine epoxy resin; There are partially acrylic (methacrylic) modified compounds such as triphenolmethane type epoxy resin and dihydroxybenzene type epoxy resin, and it is desirable to use these compounds in an amount of 50% or less, preferably 40% or less of the total resin composition.

As the photopolymerization initiator used in the present invention, a combination of the compound represented by the above formula (2) and a thioxanthone compound is most suitable. Generally, in a colored photopolymerizable composition in which a pigment is dispersed in a photopolymerizable resin, 1)
The ultraviolet light necessary for the photopolymerization initiator to generate radicals is absorbed by the pigment, making it impossible to generate sufficient radicals. 2) In systems that do not use oxygen barrier membranes such as PVA,
Radicals are captured by oxygen, and sufficient photopolymerization cannot be achieved. I have a problem with that.

The combination of the compound represented by formula (2) and the thioxanthone photopolymerization initiator was extremely good in terms of photocurability and economic efficiency. Specific examples of thioxanthone compounds include 2-chlorothioxanthone;
, 4-diethylthioxanthone; 2,4-diisopropylthioxanthone; 2,4-dimethylthioxanthone;
Examples include isopropylthioxanthone. The compound represented by formula (2) and the thioxanthone compound each account for 0.5 to 0.5 of the total weight of the photopolymerizable compounds.
It is preferably used within a range of 10% by weight.

In the present invention, a hexaarylbisimidazole compound and a hydrogen donor may be further added to the above combination as a photopolymerization initiator. Examples of hexaarylbisimidazole compounds are U.S. Patent No. 37
84557 or European Patent-A24629, but particularly good ones include 2
,2'-bis-(o-chlorophenyl)-4,4',5
, 5'-tetraphenylbisimidazolyl and 2,2
'-Bis(o-chlorophenyl)-4,4', 5,5'
-Tetra-(p-methoxyphenyl)bisimidazolyl is mentioned, and it is desirable to use it in a range of 0.5 to 10% by weight based on the photopolymerizable compound.

As the hydrogen donor, aromatic mercaptan compounds, aromatic amine compounds, etc. are used. Among these, aromatic mercaptan-based hydrogen donors preferably have benzene or a heterocyclic nucleus and one or two mercapto groups; in the case of two substitutions, one mercapto group is an alkyl , aralkyl, or phenyl substitution, and furthermore, it may be a dimer with an alkylene group interposed therebetween, or a dimer in the form of a disulfide. Particularly preferred examples include 2-mercaptobenzothiazole and 2-mercaptobenzoxazole, and it is desirable to use them in an amount of 0.5 to 10% by weight based on the photopolymerizable compound.

Next, as the aromatic amine hydrogen donor,
It is preferable to have benzene or a heterocycle as the core and one or two amino groups, and the amino group may be substituted with an alkyl group or a substituted alkyl group. The monoamino compound may further include a carboxyl group, an alkoxycarbonyl group, a substituted alkoxycarbonyl group, a phenoxycarbonyl group, a substituted phenoxycarbonyl group, or
Those substituted with a nitrile group or the like are preferable. Especially preferred is

[0033]

[Chemical formula 10]

These are desirably used in an amount of 0.5 to 10% by weight based on the photopolymerizable compound. Since the pigment used in the present invention needs to transmit visible light, it is desirable that the particle size is 1/2 or less of the wavelength of the transmitted light, and more preferably, it is effective to use a pigment that is dispersed with an average number particle size of 200 nm or less. . Preferred examples of blue pigments include phthalocyanine pigments; red pigments include quinacridone pigments, perylene pigments, pyrrolo-pyrrole pigments, and anthraquinone pigments; and preferred examples of green pigments include halogenated phthalocyanines. These pigments may be used alone, or other pigments may be added to adjust the color. Further, as the pigment for the black matrix, carbon, titanium carbon, iron oxide, azo black pigment, etc. may be used alone or in combination of two or more. These red, green, blue, and black fine particle pigments are contained in an amount of 10 to 60% by weight, preferably 20 to 50% by weight based on the photopolymerizable compound.
It is desirable to use it within a range of % by weight.

The photopolymerizable composition for color filters of the present invention contains a compound represented by formula (1), a compound represented by formula (2), a thioxanthone compound, and optionally a photopolymerizable and/or thermally polymerizable compound. It can be obtained by mixing the chemical compounds in the proportions described above. It is preferable that the mixing is performed using a mixer or a disperser while processing. The obtained composition of the present invention can also be filtered to remove coarse particles and foreign substances. When performing filtration, a filter with a pore diameter of 1 μm or less, preferably 0.5 μm or less is used.

A general method for preparing a color filter using the photopolymerizable composition of the present invention is as follows. In the present invention, the photopolymerizable composition is diluted with an organic solvent (for example, methyl cellosolve, ethyl cellosolve) as necessary to form a coating solution, which is applied to a substrate using a spinner or the like, and the solvent is dried. Obtain a smooth coating. The coating film thus obtained is irradiated with ultraviolet rays through a negative mask in order to form a desired image. At this time, a device such as mask alignment is used so that the entire coating film is uniformly irradiated with parallel light. Next, this light-irradiated coating film is exposed to running water of an alkaline aqueous solution or in a shower to dissolve the uncured portions and then developed to obtain the desired image (color filter).

The present invention will be explained in more detail with reference to Examples below.

【Example】

Example 1. A photosensitive resin composition having the following composition was prepared.

[0039] Nippon Kayaku Kayarad R5056
31.5g

[0040]

[Chemical formula 11]

(X is

[0042]

[Chemical formula 12]

[0043] and

[0044]

[Chemical formula 13]

[0045] The ratio of (a) and (b) is 2:1. )
Nippon Kayaku Kayarad R2099
6.75g (X in formula (9)
(b) above and (c) below

[0046]

[Chemical formula 14]

[0047] where the ratio of (a) and (b) is 1:1
represents. ) Nippon Kayaku Kayarad DPHA
6.75g (acrylic acid ester photopolymerizable resin) 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-bu
Thanon
1.0
g 2,4-diethylthioxanthone
0.5g ethyl cellosolve acetate
100g

Red, green, blue, and black pigment pastes to be added to the above photosensitive resin composition were prepared as follows.

[0049]

To 20 parts of the above pigment composition for each color, 4 parts of a sorbitan fatty acid ester compound was added as a dispersant, and 76 parts of ethyl cellosolve acetate were added, followed by dispersion using a sand mill. Here, the decentralized red, green,
For blue, the average number distribution of each pigment particle was 200 nm or less. This pigment paste was added in an amount of 40% by weight to the photosensitive resin composition, and after being further processed in a sand mill, the photopolymerizable resin composition for color filters of the present invention was filtered through a 1μ filter in a pressure filtration machine. Obtained.

Application example 1. The photopolymerizable resin composition obtained in Example 1 was applied using a spin coater to a smooth glass plate that had been washed with water, alcohol, and chlorofluorocarbon, and dried at 100° C. for 5 minutes. The coating film thus obtained was exposed to air through a negative mask using a mask aligner MA-10 manufactured by Mikasa Co., Ltd. Next, it was prebaked at 100° C. for 15 minutes, and developed for 60 seconds in running water of a 1% by weight aqueous sodium carbonate solution at 25° C. to obtain a color filter. The film thickness of each color of the color filter thus obtained is shown below.

[0052]

FIG. 1 shows the spectrum of the color filter obtained under the above conditions.

Example 2, Application Example 2 A photopolymerizable composition for a color filter was prepared in the same manner as in Example (1) using the following resin composition, and a color filter was produced in the same manner as in Application Example 1. Nippon Kayaku Kayarat R5056
31.5g
Nippon Kayaku Kayarat R2099
6.75g Nippon Kayaku Kayarat DPHA
6.75g 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone

1.0g 2,4 dienalthioxanthone
0.5g 2,2'-bis-(
o-chlorophenyl)-4,4',5,5'-tetraphenylbisimidazolyl
0
．． 5g 2-mercaptobenzothiazole
0.5g
Ethyl cellosolve acetate
100g

[
Examples 3 to 20, Application Examples 3 to 20 Using the resin compositions shown in Tables 3 to 8, photopolymerizable compositions for color filters were prepared in the same manner as in Example 1, and color filters were prepared in the same manner as in Application Example 1. Created. Tables 3 to 8 show the blending ratios of each component of groups A to E used in the examples. The raw materials used are shown below. (The numbers in each group are cited in the table below.)

(Group A: Compounds represented by general formula (1))1. Said Nippon Kayaku Kayarad R50562.
In formula (9), X is

[0057]

[Chemical formula 15]

and

[0059]

[Chemical formula 16]

A compound in which the ratio of (d) and (e) is 2:1. 3. In the following formula (10)

[0061]

[Chemical formula 17]

X is (a) and (b) above, and (a
) and (b) in a ratio of 2:1. In the formula (10), X is (d) and (e), and (
A compound in which the ratio of d) and (e) is 2:1. 5. In the above formula (9), X is (a) and (b)
A compound in which the ratio of (a) and (b) is 1:1. 6. In the above formula (9), X is (d) and (e)
A compound in which the ratio of (d) and (e) is 1:1.

7. In the above formula (10), X is (a
) and (b), where the ratio of (a) and (b) is 1:
A compound that is 1. 8. In the above formula (10), X is (d) and (e
), in which the ratio of (d) and (e) is 1:1 (group B: photopolymerizable resin) 9. Acrylic ester type Kayarat DPHA10 by Nippon Kayaku. Acrylic acid ester type Kayarat RP104011 manufactured by Nippon Kayaku.
Acrylic ester type Kayarat TMPTA12 manufactured by Nippon Kayaku. Cypentaerythritol hexamethacrylate

(Group C: Thermopolymerizable resin) 13. Glycidyl ether-based Yuka Shell Epoxy Epicoat 82814. Glycidyl ether type Nippon Kayaku AK60115. Resorcin diglycidyl ether 16. Hydroquinone diglycidyl ether (Group D: other resins) 17. Said Nippon Kayaku Kayarat R
209918. glycidyl methacrylate

00
65] (Group E: Photopolymerization initiator) 19. Benzophenone type manufactured by Ciba Geigy
Irgacure 36920. Thioxanthone type Nippon Kayaku Kayacure DETX21.
Isopropylthioxanthone22. 2,2'-bis-(o-chlorophenyl)-4,4',5,5'-tetraphenylbisimidazolyl23.
2-Mercaptobenzothiazole24. 2-Mercaptobenzothioxole25. Michael's Ketone 26. Benzoic acid ester-based Nippon Kayaku Kayacure EPA

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

Comparative Example 1 A photopolymerizable composition for a color filter was prepared in the same manner as in Example 1 using the following resin composition. Benzyl methacrylate/methacrylic acid copolymer (
70/30 molar ratio) 30g Pentaerythritol tetramethacrylate
7.7g 4-[P-N,N-di(ethoxycarbonylmethyl)]-2,6-di(trichloromethyl)-S-triazine
0.3g ethyl cellosolve acetate
62g When a color filter was prepared using the above composition in the same manner as in Application Example 1, the photopolymerization was insufficient and the image peeled off during development.

[0073]

[Effects of the Invention] It has become possible to produce a color filter with a simple process, high resolution, and good heat resistance and light resistance.

[Brief explanation of drawings]

Figure 1 shows the spectrum of the color filter obtained in Application Example 1. In FIG. 1, the horizontal axis shows wavelength and the vertical axis shows absorbance.

Claims (7)

[Claims] Claim 1: A compound represented by the following formula (1) [Formula 1] (wherein X represents [Formula 2] and [Formula 3], and R1, R2, and R3 are each H or C
H3, A represents an aliphatic or cyclic hydrocarbon chain, and n represents 1-20. ) and, as a photopolymerization initiator, a photosensitive resin consisting of a compound represented by the following formula (2) [Chemical formula 4] and optionally other photopolymerization initiators, a thioxanthone compound, a pigment, and optionally a photopolymerizable and A photopolymerizable composition for a color filter, characterized in that it contains/or a thermally polymerizable compound. Claim 2: Claim 1, wherein the photopolymerizable compound is a compound having at least one or more functional ethylenically unsaturated double bond.
The photopolymerizable composition for color filters described in . 3. The photopolymerizable composition for a color filter according to claim 1, wherein the thermally polymerizable compound is a compound having at least a bifunctional or higher functional epoxy group. 4. The photopolymerizable composition for a color filter according to claim 1, further comprising a hexaarylbisimidazole compound and a hydrogen donor as other photopolymerization initiators. 5. The photopolymerizable composition for color filters according to claim 4, wherein the hydrogen donor is an aromatic mercaptan. 6. The photopolymerizable composition for a color filter according to claim 4, wherein the hydrogen donor is an aromatic compound having an amino group. 7. The photopolymerizable composition for a color filter according to claim 5, wherein the aromatic mercaptan is 2-mercaptobenzothiazole or 2-mercaptobenzoxazole.