JPH05333551A - Water-soluble cooloring paste and water-soluble color resist using that - Google Patents

Abstract

PURPOSE:To provide a water-soluble coloring paste excellent in dispersibility of pigments, light-transmitting property, color quality, and heat resistance which is not dangerous for handling nor causes environmental polution, and to provide a water-soluble color resist using this paste. CONSTITUTION:This water-soluble coloring paste essentially consists of water, surfactant, org. pigment and dispersant. The dispersant consists of a mixture of polyvinyl alcohol and polyacrylamide. This polyvinyl alcohol has >=50% saponification degree and is excellent in dispersibility of pigments, lighttransmitting property, and color quality. The polyacrylamide has excellent heat resistance. The water-soluble coloring paste is mixed with a water-soluble crosslinking agent such as diazo resin to obtain the water-soluble color resist.

Description

Detailed Description of the Invention

[0001]

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

[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 this color resist is composed of a photoresist composed of a photosensitive compound and a color paste mixed therein, and the color resist is evenly applied on a transparent substrate and selectively. The color filter layer is formed by exposure and development.

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. This colored paste has the advantage of excellent color tone and storage stability because of its good pigment dispersibility.

However, since the above polyvinyl alcohol resin is poor in heat resistance, there is a problem that it is apt to discolor due to thermal deterioration.

The present invention has been made by paying attention to such a problem, and the problem is that there is no danger of causing a danger in handling and environmental pollution, and that the pigment dispersibility and the light transmission are not caused. To provide a colored paste having excellent properties, color quality and heat resistance, and a color resist using the same.

[0009]

The inventors of the present invention have made extensive studies in order to solve the above problems. As a result, the degree of saponification of polyvinyl alcohol is set to a certain range, and polyacrylamide is added to the polyvinyl alcohol. It was discovered through various experiments that the heat resistance is improved and the function as a dispersant is stably maintained when these are mixed, and the present invention has been completed.

That is, the invention according to claim 1 is premised on a water-soluble coloring paste containing water, a surfactant, an organic pigment, and a dispersant as main components, and the dispersant has a saponification degree of 5 or less.
It is characterized by being composed of a mixture of 0% or more of polyvinyl alcohol and polyacrylamide.

In such technical means, the above-mentioned polyvinyl alcohol (PVA) is a vinyl resin having a hydroxyl group which is required by completely saponifying polyvinyl acetate obtained by polymerizing vinyl acetate.

In the partial saponification, part of the hydroxyl groups is O.
It is COCH ₃ , and the structural formula at this time is shown below.

[0013]

[Chemical 1] Here, the saponification degree is represented by m / (m + n) × 100%.

This partially saponified polyvinyl alcohol is excellent in dispersibility and light transmittance, but if the saponification degree is less than 50%, its water solubility becomes small and it becomes unsuitable for the use of the present invention. Therefore, the polyvinyl alcohol applied in the present invention needs to have a saponification degree of 50% or more, and an average degree of polymerization of 300 to 3000.
The thing of a grade is preferable. Furthermore, in consideration of the compatibility with polyacrylamide described below, the saponification degree of polyvinyl alcohol is preferably in the range of 75% to 90%. Then, by blending the following polyacrylamide with polyvinyl alcohol whose saponification degree is adjusted to 50% or more, it is possible to obtain a colored paste having excellent storage stability.

That is, the polyacrylamide is a polymer represented by the following structural formula and has a function of forming a dispersant together with the polyvinyl alcohol and improving the heat resistance thereof.

[0016]

[Chemical 2] (However, in the formula, n is 20 to 20000, R ₁ is H, CH
_{3, C 2 H 5, C} 3 indicates one of the H _7, R ₂
Represents H, CH ₃ , C ₂ H ₅ , C ₃ H ₇ , or a substituent represented by the following structural formula. )

[Chemical 3] Next, the organic pigment applicable in this technical means is not particularly limited and any pigment can be used, for example,
Pigment Red 149 (Permanent Red BL), Pigment Red 144 (Cromophtal Red type)
l) etc., but Pigment Green 7
(Phthalocyanine green), Pigm as a blue organic pigment
ent Blue 15 (copper phthalocyanine) and the like.

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

[0018]

[Chemical 4] (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 5] In addition to the fatty acid polyethylene glycol ester represented by the following structural formula,

[Chemical 6] Examples thereof include polyoxyethylene oleyl ether.

In the water-soluble coloring paste according to claim 1, while the polyvinyl alcohol having a saponification degree of 50% or more, the surfactant and water are stirred at room temperature, the organic pigment is gradually added thereto. After mixing well, add glass beads and knead and disperse with a sand mill,
It is obtained by mixing an aqueous solution of polyacrylamide.

Next, the invention according to claim 2 is this claim 1
The present invention relates to a water-soluble color resist using the water-soluble color paste according to the above.

That is, the invention according to claim 2 is a water-soluble color resist comprising the water-soluble colored paste according to claim 1 and a water-soluble photocrosslinking agent mixed therein.

Examples of the compound applicable to the water-soluble photocrosslinking agent in the invention according to claim 2 are dichromates such as ammonium dichromate and potassium dichromate, and p- represented by the following structural formula. Formalin condensate of diazodiphenylamine,

[Chemical 7] 4-diazo-3-methoxydiphenylamine dimer represented by the following structural formula,

[Chemical 8] And a water-soluble azide compound represented by the structural formulas (1) to (3) below.

[0023]

[Chemical 9] The water-soluble color resist can be developed with an aqueous solution such as water. Therefore, the photolithography process can be performed without using the organic solvent.

[0024]

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.

The dispersant for dispersing the organic pigment has a saponification degree of 50, which is excellent in its dispersibility, light transmittance and color quality.
% Of polyvinyl alcohol and polyacrylamide having excellent heat resistance, it is possible to improve dispersibility as a colored paste, light transparency, color quality and heat resistance.

On the other hand, according to the invention according to claim 2 to which the water-soluble coloring paste according to claim 1 is applied, the dispersibility and light transparency of the water-soluble coloring paste as well as the color quality and heat resistance are improved. Therefore, it is possible to form a transparent color filter layer having a high color purity, and it is possible to stably store the color filter layer for a long period of time due to the improved dispersibility.

[0027]

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

Example 1 Using polyvinyl alcohol (PVA) having an average degree of polymerization of 2000 and a degree of saponification of 88%, 1
An aqueous solution of 0 wt% was prepared, and 80 g of water, 100 g of polyoxyethylene oleyl ether as a surfactant, and Pigment Blue as an organic pigment were added to 100 g of this aqueous solution.
10 g of 15 (copper phthalocyanine) was added, 250 g of glass beads was further added as a medium, and the mixture was kneaded and dispersed in a sand mill for 2 hours. The average particle size of the pigment at this time was 0.05 μm.

Next, the pigment liquid 100 thus obtained is obtained.
50 g of a 10 wt% aqueous solution of polyacrylamide (average polymerization degree: 1000) represented by the following structural formula was added to and mixed with g to obtain a water-soluble colored paste.

[0030]

[Chemical 10] A heat resistance test and a storage stability test were conducted on the water-soluble colored paste thus obtained. The results are shown in Table 1.

In the heat resistance test, the above water-soluble colored paste was spin-coated on a glass substrate to form a coating film having a thickness of 1 μm, and the coating film was placed in an oven at 230 ° C. for 1 hour to obtain its light transmittance (%). ) Was measured.

The storage stability test was carried out by measuring the viscosity of the above water-soluble colored paste and measuring the change over time in the yield value. That is, the relative yield value was calculated by the following formula, and the storage stability was evaluated by this relative yield value. The smaller the relative yield value, the better the storage stability.

(Relative Yield Value) = (Yield Value after 30 Days of Storage) / (Initial Yield Value at the Time of Preparation of Water-Soluble Colored Paste) [Comparative Example 1] Then, a heat resistance test and a storage stability test were conducted in the same manner as in Example 1.

The results are shown in Table 1.

[0035]

[Table 1] [Evaluation] As is clear from Table 1, the heat resistance was inferior in Comparative Example 1 in which polyacrylamide was not mixed,
After heating, a remarkable decrease in transmittance was observed.

On the other hand, in Example 1 in which polyacrylamide was mixed, it was confirmed that the heat resistance was improved and the change in transmittance due to heating was small.

It was also confirmed that there is no problem with the storage stability of the water-soluble colored paste.

Example 2 A water-soluble color resist was obtained by mixing 10 g of the water-soluble colored paste obtained in Example 1 with 0.05 g of a diazo resin represented by the following structural formula as a photo-crosslinking agent.

[0039]

[Chemical 11] This water-soluble color resist is coated on a glass substrate (coating thickness is 1 μm) and 100 to 30 using an ultra high pressure mercury lamp.
Patternwise exposure with an irradiation dose of 0 mJ / cm ² , and
The color filter layer was formed by developing with water as a developing solution. The resolution of this color filter layer was about 10 μm.

Table 2 shows the heat resistance test results of the obtained color filter layers.

The heat resistance test was conducted in the same manner as in Example 1.

[Comparative Example 2] A water-soluble color resist was obtained in the same manner as in Example 2 except that the above-described pigment liquid before mixing with polyacrylamide was used as a water-soluble coloring paste.
A color filter layer was formed and its heat resistance test was conducted. The results are shown in Table 2.

[0043]

[Table 2] "Evaluation" As is apparent from Table 2, in Comparative Example 2 in which polyacrylamide was not mixed, heat resistance was poor,
After heating, a remarkable decrease in transmittance was observed.

On the other hand, it was confirmed that in Example 2 in which polyacrylamide was mixed, the heat resistance was improved and the change in transmittance due to heating was small.

[0045]

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

The dispersant for dispersing the organic pigment has a saponification degree of 50, which is excellent in its dispersibility, light transmittance and color quality.
% Of polyvinyl alcohol and polyacrylamide having excellent heat resistance, it has the effect of improving dispersibility as a colored paste, light transparency, and color quality and heat resistance.

On the other hand, according to the invention according to claim 2 to which the water-soluble coloring paste according to claim 1 is applied, the dispersibility and light transparency of the above-mentioned water-soluble coloring paste, and the color quality and heat resistance are improved. Therefore, it is possible to form a transparent color filter layer having a high color purity, and it is possible to store the water-soluble color resist stably for a long period of time as the dispersibility is improved.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication location G03F 7/004 511 (72) Inventor Eri Kino 2-31-1-303 Kasuga, Tsukuba, Ibaraki

Claims (2)

[Claims] 1. A water-soluble coloring paste containing water, a surfactant, an organic pigment, and a dispersant as main components, wherein the dispersant is a mixture of polyvinyl alcohol and polyacrylamide having a saponification degree of 50% or more. A water-soluble colored paste characterized in that it is composed. 2. A water-soluble color resist comprising the water-soluble colored paste according to claim 1 mixed with a water-soluble photocrosslinking agent.