JPH05215914A - Coloring paste for color resist - Google Patents

Abstract

PURPOSE:To prevent danger for handling and environmental pollution, and also, to improve light resistance, heat resistance and light transmittivity and pigment dispersibility by constituting a dispersant of a specific polyacetal resin. CONSTITUTION:The coloring paste is mainly composed of water, a surfactant, an organic pigment and a dispersant, and the dispersant is constituted of a polyacetal resin shown by a formula. In the formula, X1 and X2 denote two groups of the same kind or different kinds in a hydroxyl group, a carboxyl group and an aldehyde group. As for this polyacetal resin, its dispersibility if satisfactory, the organic pigment is dispersed uniformly and satisfactorily in a water solution, and also, the dispersed organic pigment is scarcely sedimented, and its dispersed state is held extending over a long period. Also, since it is a transparent resin, it is excellent in light transmittivity, and also, excellent in light resistance and heat resistance, and it is not discolored even if heated in the air, therefore, it has an action by which a color filter layer whose color purity is high can be formed, and a color filter of a high quality is derived.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a colored paste for a color resist used in the production of a color filter, and in particular, there is no danger of causing a handling risk and environmental pollution, and a heat resistance and a heat resistance. The present invention relates to improvement of a color paste for a color resist, which is excellent in light resistance, pigment dispersibility and light transmittance.

[0002]

2. Description of the Related Art A color filter of this type is mainly composed of a transparent substrate such as glass and a color filter layer provided at a pixel portion on the transparent substrate and coloring the transmitted light for each pixel. The color filter layer is formed of a color resist containing an organic pigment having a color corresponding to each color. The main part of the color resist is composed of a colored paste and a photosensitive compound mixed therein, and the color resist is uniformly applied on a transparent substrate, and selectively exposed and developed. The color filter layer is formed.

By the way, as a color paste applied to the above color resist, for example, Japanese Patent Laid-Open No. 60-1842.
As described in JP-A-04-2004, an organic solvent, an organic pigment dispersed therein, a surfactant, and a dispersant composed of a specific polyimide precursor for uniformly dispersing the pigment are mainly used. What is used as an ingredient is known.

[0004]

However, since this colored paste uses an organic solvent, it has a danger of handling and a harmful effect of causing environmental pollution due to disposal, which is a great problem in terms of production and management. There was a problem that required labor and cost.

[0005] Further, the polyimide-based polymer exhibits brownish coloring, and when applied to a color filter that requires highly saturated red, green, and blue colors, it causes a decrease in color purity and thus has a high quality. There was a problem that it was not possible to manufacture various color filters.

On the other hand, a water-soluble colored paste in which polyvinyl alcohol, which is a water-soluble resin, is applied to the above dispersant has also been developed for the purpose of eliminating handling hazards and environmental pollution.

However, the polyvinyl alcohol resin is inferior in dispersibility to the polyimide-based polymer, and
Since the heat resistance is not sufficient, the transmittance decreases due to the heat treatment during the production, and there is a problem that a high quality color filter cannot be produced like the colored paste to which the above polyimide polymer is applied.

The present invention has been made by paying attention to such a problem, and its problem is that there is no danger of causing a handling risk and environmental pollution, and the light resistance and heat resistance thereof are high. Another object of the present invention is to provide a colored paste for a color resist which is excellent in light transmittance and pigment dispersibility.

[0009]

That is, the invention according to claim 1 is premised on a colored paste for a color resist containing water, a surfactant, an organic pigment, and a dispersant as a main component. It is characterized by being constituted by a polyacetal resin represented by the following structural formula.

[0010]

[Chemical 3] (However, in the formula, X ₁ and X ₂ represent _two groups of the same type or different types among a hydroxyl group, a carboxyl group, and an aldehyde group.) In such technical means, the polyacetal resin represented by the above structural formula is dispersed. Since the organic pigment has good properties and is dispersed uniformly and satisfactorily in an aqueous solution to obtain a colored paste having excellent optical properties, the dispersed organic pigment is difficult to settle and its dispersed state is maintained for a long period of time. It has the effect of improving storage stability.

Further, the polyacetal resin is a colorless and transparent resin which is excellent in its light-transmitting property, and is also excellent in light resistance and heat resistance, so that it is discolored even if it is heated in air at 230 ° C. for about 1 hour. Since it does not occur, it has an effect of enabling the formation of a color filter layer having a high color purity, and therefore, these have an advantage that a high quality color filter is required by working together.

Regarding the polyacetal resin represented by the above structural formula, when both X ₁ and X ₂ are hydroxyl groups and the molecular weight is 400 to 600, the water solubility is improved and the dispersibility is further improved. Becomes

The invention according to claim 2 has been completed for such a technical reason, and on the premise of the color paste for color resist according to claim 1, the dispersant is represented by the following structural formula and has a molecular weight of It is characterized by being composed of 400 to 600 polyacetal resin.

[0014]

[Chemical 4] Next, the organic pigment applicable in the invention according to claims 1 and 2 is not particularly limited, and any pigment can be used,
For example, as red organic pigments, Pigment Red 149 (Permanent Red BL), Pigment Red 144 (Cromophtal R
ed typel), etc., but as a green organic pigment, Pigment Gr
Examples include een 7 (phthalocyanine green) and blue organic pigments such as Pigment Blue 15 (copper phthalocyanine).

Further, an anionic surface active agent or a nonionic surface active agent may be used as the surface active agent, and the anionic surface active agent may be a polycarboxylic acid type anionic surface active agent or a sulfosuccinate type anionic surface active agent. In addition to the surfactant, dialkylsulfosuccinic acid ester sodium salt represented by the following structural formula can be used.

[0016]

[Chemical 5] (However, in the formula, R represents an alkyl group.) On the other hand, as the nonionic surfactant, polyoxyethylene polyoxypropylene glycol ether represented by the following structural formula,

[Chemical 6] In addition to the fatty acid polyethylene glycol ester represented by the following structural formula,

[Chemical 7] Examples thereof include polyoxyethylene oleyl ether.

The color paste for a color resist according to any one of claims 1 to 2 is gradually added with an organic pigment while stirring a dispersant composed of the polyacetal resin, a surfactant and water at room temperature. When sufficiently mixed, glass beads are added, and the mixture is kneaded and dispersed by a sand mill to obtain the value.

In applying the colored paste, a photosensitive compound is mixed in the paste to obtain a color resist for producing a color filter, and a color filter layer is formed on a transparent substrate according to a well-known photolithography process. To produce a desired color filter.

[0019]

According to the first aspect of the present invention, since the aqueous solution is applied to the dispersion medium and the organic solvent is not used as in the conventional case, the risk of handling it can be reduced and the environmental pollution can be prevented. Become.

Further, since the dispersant for dispersing the organic pigment is composed of a polyacetal resin represented by the following structural formula, which is excellent in heat resistance and light resistance, as well as in dispersibility and light transmittance, it is transparent and has high color purity. A color filter layer can be formed and its dispersibility is improved to improve storage stability.

[0021]

[Chemical 8] (However, in the formula, X ₁ and X ₂ represent _two groups of the same type or different types among a hydroxyl group, a carboxyl group, and an aldehyde group.) On the other hand, according to the invention of claim 2, the dispersant comprises:
Since the polyacetal resin having a molecular weight of 400 to 600 represented by the following structural formula is used and the dispersibility thereof is further improved, the storage stability thereof can be further improved.

[0022]

[Chemical 9]

[0023]

EXAMPLES Examples of the present invention will be described in detail below.

It has a molecular weight of about 500 and is represented by the following structural formula.
In 100 parts by weight of a 10% aqueous solution of polyacetal resin, 90 parts by weight of water and 0.2% of polyoxyethylene polyoxypropylene glycol ether as a surfactant are added.
Add 10 parts by weight of chromophthal red (a red pigment manufactured by Ciba Geigy) while stirring well with a stirrer.
Parts by weight were added and mixed.

[0025]

[Chemical 10] Then, when sufficiently mixed, 250 parts by weight of glass beads were added thereto, and the mixture was kneaded and dispersed in a sand mill for 2 hours to obtain a colored paste.

The colored paste for color resist thus obtained was measured by a particle size distribution meter by a centrifugal sedimentation method, and it was confirmed that the weight average particle diameter was 0.075 μm and the dispersibility thereof was good. .

Next, this colored paste was applied on a transparent glass substrate and then heated in an oven at 230 ° C. for 1 hour. When the light transmittance of the substrate before and after heating was measured with a spectrophotometer, the light transmittance of red light with a wavelength of 700 nm was high at about 70% before and after heating, and the change in light transmittance due to heating was small. It was less than 2%.

Therefore, it was confirmed that it is possible to form a transparent and high color purity color filter layer by applying this coloring paste.

[Comparative Example] A colored paste was obtained in the same manner as in the Example except that polyvinyl alcohol having a saponification degree of 99 mol% was used as the dispersant instead of the polyacetal resin.

The weight average particle diameter of this coloring paste is 0.1.
It was 2 μm, and its dispersibility was inferior to that of the example.

Further, the light transmittance of red light having a wavelength of 700 nm after heating at 230 ° C. for 1 hour was lowered by 8% as compared with that before heating, and its heat resistance was also inferior.

[0032]

According to the invention of claim 1, since the aqueous solution is applied to the dispersion medium and the organic solvent is not used as in the conventional case, the danger of handling the same is reduced and the environmental pollution can be prevented. Have

Further, since the dispersant for dispersing the organic pigment is composed of a polyacetal resin having excellent heat resistance and light resistance, as well as dispersibility and light transmission, it is possible to form a transparent color filter layer having high color purity. At the same time, its dispersibility is improved and storage stability can be improved.

Therefore, there is an effect that a high quality color filter can be reliably manufactured.

On the other hand, according to the second aspect of the present invention, the dispersibility of the colored paste is further improved, so that the storage stability thereof can be further improved and a higher quality color filter can be manufactured. .

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[Procedure amendment]

[Submission date] October 14, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

Regarding the polyacetal resin represented by the above structural formula, it is preferable that both X ₁ and X ₂ are hydroxyl groups and the degree of polymerization n is 2000 or less, especially when the molecular weight thereof is about 400 to 600. The property is improved and the dispersibility is further improved.

Claims (2)

[Claims] 1. A colored paste for a color resist containing water, a surfactant, an organic pigment, and a dispersant as main components, wherein the dispersant is composed of a polyacetal resin represented by the following structural formula. Characteristic colored paste for color resist. [Chemical 1] (However, in the formula, X ₁ and X ₂ represent _two groups which are the same or different from each other among a hydroxyl group, a carboxyl group and an aldehyde group.) 2. The colored paste for a color resist according to claim 1, wherein the dispersant is composed of a polyacetal resin having the following structural formula and having a molecular weight of 400 to 600. [Chemical 2]