JPH04153657A - Photopolymerizable composition for forming color filter - Google Patents

Abstract

PURPOSE:To obtain a color filter high in precision and producing no acid and no other substance by forming the photopolymerizable composition comprising a specified alkali-soluble polymer, a photopolymerizable compound having one or more ethylenically unsaturated double bonds, a photopolymerization initiator, fine pigment particles, and an organic solvent. CONSTITUTION:The photopolymerizable composition comprises the alkali-soluble polymer having repeating units of formula I (m is 1 - 3; n is 6 - 8; and R is 1 - 10 C alkyl or cycloalkyl.), the photopolymerizable compound having one or more ethylenically unsaturated double bonds, the photopolymerization initiator, the fine pigment particles, and the organic solvent. The component of formula I is a binder resin and it has 2 functions; the first is to uniformly coat a substrate with the composition, and the second is to be dissolved in water and to wash off the unnecessary matter when the unexposed composition is developed with alkaline water, thus permitting the process to be short and economic, water development superior in environmental pollution control to be executed, acid and the like not to be produced, and a color filter high in reliability as electronic parts to be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a photopolymerizable composition colored with a pigment for forming transparent colored images, and is applicable to color liquid crystal displays, charge-coupled devices, color sensors, etc. The present invention relates to a composition used for preparing color filter pixels for optical applications.

Conventional color filters are manufactured by forming R, G, and B primary color elements or Y, M, and C primary color elements on a transparent substrate such as glass or plastic, or an opaque substrate such as silicon.

Color filter manufacturing methods include dyeing methods, electrodeposition methods, printing methods, and the like.

Among these methods, the dyeing method can produce high-definition products, but it has the disadvantage of a long process and poor durability (heat resistance, weather resistance, moisture resistance).

The electrodeposition method has a problem in terms of driving the liquid crystal because a color filter is constructed on the electrodes.

The printing method has the advantage of being inexpensive because it is an application of existing printing technology, but it also has drawbacks such as poor surface smoothness due to insufficient ink and limited high-definition patterns.

In recent years, in order to improve these problems, a "pigment dispersion method" in which finely divided pigments are dispersed in a photoresist composition has been published in JP-A-1-152449 and JP-A-1-2549.
18 have been developed. Although the process has been improved and the quality as a color filter is excellent, it is said that because it uses triheromethane as a photopolymerization initiator, HCI (hydrochloric acid) may be generated after photocuring. There are drawbacks. Since HCI is a strong acid electrolyte, it leaks through the resin film into the transparent electrodes and liquid crystal parts, causing corrosion and malfunction, and there are many problems when used in electronics parts.

Problems to be Solved by the Invention The problems of the prior art described above have been solved. In other words, it is a photosensitive material for forming color filters that is short in terms of process, can be developed with water, has high definition, is highly durable, does not generate acids, and can be used as an electronic component. An object of the present invention is to provide a resin composition.

Means for Solving the Problems The present invention is a pigmented photopolymerizable composition for forming transparent colored images. That is, (A) the following general formula CI) (wherein m is 1 to 3, n is 6 to 8, and R is carbon number 1 to 10)
an alkyl group or a cycloalkyl group) (B) a photopolymerizable compound having two or more ethylenically unsaturated double bonds (C) a photopolymerization initiator (D) ) A photopolymerizable composition for forming a color filter comprising a fine particle pigment (E) an organic solvent.

In the present invention, component (A) can be called a binder, and has the function of (1) uniformly coating the composition on the substrate, and (2) alkalinizing the composition in the unexposed areas after exposure. When developing with water, the water solution has two functions: washing it away from the substrate.

Component (A) includes, for example, styrene and maleic anhydride in 1 to 1
It can be obtained by copolymerizing at a molar ratio of 3:1 and partially esterifying it with an alcohol having an alkyl group or cycloalkyl group having 1 to 10 carbon atoms using a known method. Also, SMA-2625, SMA-173 from the market
52 (Atochemi Co., Ltd.), etc. Those having a molecular weight of 1500 to 3000 and an acid value of 150 to 300 are preferable in terms of solubility and washability.

Component (B) is a photopolymerizable compound having one or more ethylenically unsaturated double bonds, and has the effect of photopolymerizing and curing the portion exposed through the mask. That is, it adheres closely to the substrate through photopolymerization, and functions to withstand subsequent alkaline water development and construct a pattern. Examples include monofunctional and polyfunctional acrylate or methacrylate monomers and oligomers. Such compounds are well known in the art and include acrylic and methacrylic esters of polyhydric alcohols such as ethylene glycol, trimethylbukpanol, pentaerythritol, etc.; acrylate- or methacrylate-terminated epoxy resins; acrylate- or methacrylate-terminated epoxy resins; Contains polyester resins, near-acrylate- or methacrylate-terminated urethane resins, etc.

Specifically, for example, polyethylene glycol mono(meth)
Acrylate, polypropylene glycol mono(meth)
Monofunctional acrylates and methacrylates such as acrylate and 2-ethylhexyl acrylate: polyethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, After adding ethylene oxide or propylene oxide to a polyfunctional alcohol such as dipentaerythritol hexa(meth)acrylate, bisphenol A diethoxy di(meth)acrylate, tri(meth)acrylooxyethyl isocyanurate, or glycerin, it becomes (meth)acrylate. There are things that have been done.

Component (C) is an initiator component that photopolymerizes component (B). If you are familiar with various literatures, you may be familiar with direct cleavage type acetophenone, phenylacetophenone, etc., hydrogen abstraction type benzophenone, thioxanthone, etc., combination of peroxy acid ester and donor type sensitizer, dye and alkyl or aryl borate, bisimidazole, etc. A hydrogen donor, a combination of an acridine compound and a hydrogen donor, a polyhalogen compound and an amine, etc. are used. Specific examples include Kayacure DETXSCTX manufactured by Nippon Kayaku.

Examples include RTX, MBP, BP, and Irgar Cure-651, 184, 500, 907 manufactured by Ciba Gaiki.

Component (D) is a pigment component for coloring the composition. Since high transparency is required for compositions used in color filters, fine particle pigments are required, and to change the average particle size below the maximum absorption wavelength of the pigment used, it is preferable to use a pigment with an average particle size of one-half or less of the wavelength. It is.

The pigments are organic pigments, such as azo pigments, phthalocyanine pigments, indigo pigments, anthraquinone pigments, perylene pigments, perinone pigments, dioxazine pigments, quinacridone pigments, isoindoline pigments, phthalone pigments, methine pigments, azomethine pigments, and metals. Complex and fused polycyclic pigments are used.

For example, the pigments used in LCD color filters are R, G.
Although it is necessary to satisfy the spectral characteristics of , B, it is better to use an anthraquinone pigment as a main component as a red pigment and adjust the color with a disazo yellow pigment or an isoindoline yellow pigment.

As the green pigment, it is preferable to use a gelatinized phthalocyanine pigment alone or toned with the yellow pigment described above.

As the blue pigment, a phthalocyanine pigment alone or a toned one with a dioxazine pigment is suitable. Suitable black pigments include carbon, titanium carbon, and ab-based pigments.

These pigments can be prepared using dispersants or resins (E) below.
It is preferable to use fine particles dispersed in the same organic solvent as the components.

Component (E) is an organic solvent component, and (A), (B)
, (C), and (D), and also serves as a dispersion medium. Examples of these solvents include ethylene glycol,
Ethylene glycol monoalkyl ethers such as monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether; diethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, etc. Types: Ethylene glycol alkyl acetates such as methyl secosolve acetate and ethyl cellosolve acetate, propylene glycol alkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and propylene glycol propyl ether acetate. be.

These solvents may be used alone or in combination of two or more. The solvent needs to be designed to have a high boiling point of 100'C to 200''C in order to obtain uniform application while considering the evaporation rate.

The content ratio of each component in the composition is as follows: component (A) is 3% by weight;
~15% (B) component is 1 to 10%, (C) component is 5 to 20% of (B) component, (D) component is 5 to 15%, and (E) component is preferably the remaining 60 to 90%. It is.

When component (A) is less than 3%, smooth coating is difficult and developability is poor. If it exceeds 15%, the adhesion of the composition to the substrate will be poor and it will easily peel off.

If the content of component (B) is less than 1%, the hardness of the photocurable resin will be insufficient and its adhesion to the substrate will be poor. If the photocurability is 10% or more, it is undesirable.

Component (C) is a photopolymerization initiator for photocuring component (B), and if it is less than 5%, component (B) cannot be sufficiently cured, making it difficult to make the composition adhere to the substrate. .20
%, it is uneconomical and components remaining in the resin after photocuring deteriorate weather resistance, which is not preferable.

If the content of component (D) is less than 5%, the density as a color filter decreases, especially if it exceeds <<15%, the transparency decreases and it is difficult to perform the function as a color filter.

When component (E) is less than 60%, the viscosity becomes high, making it difficult to coat the substrate and making it difficult to obtain smoothness. If it exceeds 90%, the viscosity becomes low, making it impossible to obtain a coating film of sufficient thickness, and making it difficult to obtain sufficient color contrast as a color filter.

The photopolymerizable composition obtained by mixing these can exhibit the main function as a composition for color filters, or may be mixed with additives in order to have an auxiliary function.

For example, a polymerization inhibitor to improve stability over time, a smoothing agent to ensure uniformity during coating, etc. may be added.

The photopolymerizable composition of the present invention can be obtained by dispersing and treating the above-mentioned components as necessary, and then mixing them. It is preferable that the obtained mixture is filtered using a filter with a pore size of about 1 μm or less (pressure filtration is performed if necessary) to align the particles and remove foreign substances.

The photopolymerizable composition of the present invention can be photocured and developed, for example, as follows.

That is, the photopolymerizable composition of the present invention is added with the above-mentioned organic solvent and additives as necessary to form a coating solution, which is applied to a substrate using a spinner or the like, and by drying the solvent, a smooth coating is prepared. After obtaining a coating film, a resin such as PVA is applied onto the coating film and dried in order to avoid contact between the coating film and oxygen that inhibits photopolymerization.

The coating film thus obtained is irradiated with ultraviolet rays through a negative mask in order to form a desired image. At this time, it is preferable to use a device such as mask alignment 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 the desired image is obtained by developing the film.

EXAMPLES The present invention will be explained in more detail with reference to Examples below. In the examples, parts indicate parts by weight.

Example 1 The following compositions were prepared and mixed.

・5MA17352 30 copies ・KAYARAD-DPHA 20 copies ・1RGActJRE 907
0.4 (Chiha Geigy, photopolymerization initiator) -KAYACURE DETX
O,2 (manufactured by Nippon Kayaku, photopolymerization initiator) - Fine particle pigment 35 (see below) - Ethyl cellosolve acetate 15 (solvent) The mixed solution was filtered under pressure using a membrane filter to obtain a photopolymerizable composition for color filters. I got something.

The fine particle pigments are shown in Table 1 below. 20 parts each of the pigments, 4 parts of a sorbitan dispersant, and 76 parts of ethyl cellosolve acetate were weighed out, and after preliminary mixing, they were atomized by a bead mill method.

The particle size was measured using a particle size distribution meter manufactured by Ogaki Electronics, and the average number distribution was 0.15 μm for red, 0.1 μm for green, 0.1 μm for blue, and 0.1 μm for black.

Application Example 1 Glass was used as a transparent substrate, cleaned with neutral detergent, water, and alcohol, and dried and prepared.

The photopolymerizable composition of Example 1 was applied to this glass using a spin coater at 1000 to 2000 RPM.
C. Dry for 10 minutes. Next, polyvinyl alcohol (
A 10% solution of GOHSENOL GC-05 (Japanese synthetic type) was similarly applied and dried.

Next, place the mask (letterpress type, test chart) on the mask aligner (manufactured by Mikasa, MA-10) and make 10 patterns.
~30 second exposure. Subsequently, baking treatment was performed by heating at 100° C. for 10 minutes. For development, sodium carbonate 1
% solution at 25°C for 160 seconds.

Coating of each color was performed in the order of black, red, green, and blue after the black matrix. The film thickness was adjusted between 0.8 and 2 μm.

The film thickness of each color is red 2.0μm, green 2.0μm, blue 1μm,
The black color was 0.8 μm.

The resulting color filter does not contain acid.

It had a high-definition pattern (30μ or less) and had excellent heat resistance and weather resistance.

Example 2.3 and Comparative Example 1.2.3 The results as shown in the right column of Table 2 were obtained in the same manner as in Example 1, except that the alkali-soluble polymer compound as the binder was changed to the compound in Table 2. Obtained.

Table 2 <Display of development results> ◎ −−−・− A pattern of 1 μm or less was obtained.

○ −・・・・・・−400μ or less! △...
-111- The pattern lacks the advantages and disadvantages.

×－－－－・Things that were not selected by the pattern.

Effects of the Invention The photopolymerizable composition for forming transparent colored images of the present invention is short and economical in terms of process, is excellent in terms of environmental protection, can be developed in water, and does not generate acid, and can be used as an electro member. It is possible to build reliable color filters.

Patent applicant: Nippon Kayaku Co., Ltd.

Claims (1)

[Claims] 1. (A) The following formula [I] ▲ Numerical formula, chemical formula, table, etc. ▼ (I) (In the formula, m is 1 to 3, n is 6 to 8, and R is 1 carbon number ~10
an alkyl group or a cycloalkyl group) (B) a photopolymerizable compound having one or more ethylenically unsaturated double bonds (C) a photopolymerization initiator (D) ) A photopolymerizable composition for forming a color filter comprising a fine particle pigment (E) an organic solvent.