JPH06175362A - Coloring paste for color resist - Google Patents

Abstract

PURPOSE:To provide such a coloring paste for a color resist that has good sensitivity and resolution and that dispersiblity of the paste does not decrease even when concn. of pigment in the paste is increased. CONSTITUTION:This coloring paste for a color resist essentially consists of pigment, surfactant, dispersant, and solvent. The dispersant consists of a mixture of high mol.wt. polymer and low mol.wt. polymer. Sensitivity is improved by the effect of the high mol.wt. polymer having high crosslinking density. Resolution is improved by the effect of the low mol.wt. polymer having small adhesion property to a substrate. First, a dispersant consisting of the high mol.wt. polyer is added and dispersed and then, a dispersant consisting of the low mol.wt. polymer is added. By this method, the high mol.wt. polymer is adsorbed to the surface of the pigment, which gives an effect to prevent reduction of dispersibility even when the concn. of pigment is increased.

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 color resist used in the production of a color filter, and more particularly, it has a good sensitivity and resolution and a high pigment concentration in the paste. The present invention also relates to an improvement in a color paste for a color resist, the dispersibility of which does not deteriorate.

[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 which is provided at a pixel portion on the transparent substrate and colors the transmitted light for each pixel. The color filter layer is formed of a color resist containing a pigment of a color corresponding to each color.

The main part of the color resist is composed of a colored paste and a photosensitive compound such as a diazo resin mixed therein, and the color resist is uniformly applied onto a transparent substrate. In addition, the color filter layer is formed by selectively exposing and developing.

By the way, as a coloring paste of this kind applied to the above color resist, there is disclosed in JP-A-60-184.
As described in JP-A-204-204, 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.

[0005]

However, in the conventional colored paste, when the dispersant is composed of a low molecular weight polymer, there is a drawback that the sensitivity is not so good due to its low crosslink density, and the pigment surface is poor. Since the adsorption layer of the adsorbed polymer also becomes thin, the dispersion stability of the pigment is poor, and the transparency and color quality of the obtained colored paste are poor.

On the other hand, when the dispersant is composed of a high molecular weight polymer, the polymer has a high adhesiveness to the substrate, and therefore, there is a defect that the pattern is not well cut at the time of development and the resolution is not so good, and the pigment concentration is low. The higher the setting, the more the pigment and the above-mentioned polymer form a structure in the solution, and the fluidity of the polymer is lowered to facilitate gelation, so that there is a problem that the dispersibility of the pigment particles is lowered.

The present invention has been made by paying attention to such a problem. The problem is that the sensitivity and the resolution are both good and the dispersibility is high even when the pigment concentration in the paste is set high. It is to provide a colored paste for a color resist that does not deteriorate.

[0008]

That is, the invention according to claim 1 is premised on a color paste for a color resist containing a pigment, a surfactant, a dispersant, and a solvent as main components, and the dispersant is It is characterized in that it is composed of a mixture of a molecular weight polymer and a low molecular weight polymer, while the invention according to claim 2 is based on the colored paste for a color resist according to claim 1, and is based on a pigment and an interface. After the dispersant composed of the high molecular weight polymer is added to the solvent containing the activator to disperse the pigment, the dispersant composed of the low molecular weight polymer is added to the solvent to disperse the pigment. It is characterized by that.

In the invention according to claim 1,
Since the dispersant is composed of a mixture of a high molecular weight polymer having a high crosslinking density and a low molecular weight polymer having a low adhesiveness to the substrate, the sensitivity and the resolution can be improved.

That is, the higher molecular weight polymer that constitutes a part of the dispersant has a higher cross-linking density and the higher the sensitivity, and the lower the molecular weight of the low molecular weight polymer, the lower the adhesion to the substrate. Therefore, the pattern is easily cut at the time of development, and the resolution is improved. Therefore, it becomes possible to improve the sensitivity and the resolution by the synergistic action of each polymer when the dispersant is composed of a mixture of a high molecular weight polymer and a low molecular weight polymer.

Further, in the invention according to claim 2, since the dispersing treatment of the pigment is first performed by adding the dispersant composed of the high molecular weight polymer, it is constituted by the high molecular weight polymer adsorbed on the surface of the pigment. The adsorption layer is stable and the dispersion stability of the pigment becomes good, and the dispersion treatment of the pigment is performed with the above high molecular weight polymer, and then the dispersant composed of the low molecular weight polymer is added to perform the dispersion treatment. For,
Even if the pigment concentration is set high, the pigment having the adsorption layer and the low molecular weight polymer do not form a structure in the solution and are difficult to gel, so that the dispersibility of the pigment particles does not deteriorate.

The invention according to claim 3 provides the invention according to claim 1.
In the inventions according to 2 to 2, the molecular weights of the high molecular weight polymer and the low molecular weight polymer capable of effectively exhibiting the above-described effects are specified.

That is, the invention according to claim 3 is claim 1
Alternatively, the low-molecular weight polymer has an average molecular weight of 5,000 to 30,000, and the high-molecular weight polymer has an average molecular weight of 80,000 to 300,000. To do.

Next, examples of the dispersant applicable to the inventions according to claims 1 to 3 include partially saponified polyvinyl alcohol (PVA). Incidentally, polyvinyl alcohol having a saponification degree of 70% to 84% is preferable because of its excellent dispersibility. In addition to this PVA, polyvinylpyrrolidone, polyethylene glycol, polyacrylamide, etc. can be applied.

Further, as the above-mentioned solvent, there is no danger in handling, and it does not cause environmental pollution upon disposal.
It is desirable to use an aqueous solvent such as water or alcohol.

On the other hand, the organic pigments applicable in the inventions according to claims 1 to 3 are not particularly limited, and any pigment can be used. For example, Pigment Red as a red organic pigment.
149 (Permanent Red BL), Pigment Red 144 (C
romophtal Red typel), etc., as a green organic pigment, Pigment Green 7 (phthalocyanine green), and a blue organic pigment, Pigment Blue 15 (copper phthalocyanine).
Etc.

Further, an anionic surfactant or a nonionic surfactant can be used as the above 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, dialkylsulfosuccinate sodium salt represented by the following structural formula can be used.

[0018]

[Chemical 1] (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 2] In addition to the fatty acid polyethylene glycol ester represented by the following structural formula,

[Chemical 3] Examples thereof include polyoxyethylene oleyl ether.

As a preferable composition of the color paste excluding the above-mentioned solvent, surfactant 0.1 to 5% pigment 5 to 30% dispersant 5 to 20% can be exemplified.

The colored paste for color resists according to claims 1 and 3 is a dispersant composed of a mixture of the high molecular weight polymer and the low molecular weight polymer,
It is obtained by gradually adding an organic pigment to a surfactant and an aqueous solvent with stirring at room temperature, adding glass beads when they are sufficiently mixed, and kneading and dispersing with a sand mill.

In the color paste for color resist according to the second and third aspects, the organic pigment is gradually added into the color paste for the color resist while stirring the dispersant consisting of the high molecular weight polymer, the surfactant and the aqueous solvent at room temperature. In addition, add glass beads when they are well mixed and knead with a sand mill.
After being dispersed, this time, it is obtained by adding a dispersant composed of a low molecular weight polymer and similarly kneading and dispersing.

Next, in applying these colored pastes, a photosensitive compound such as a diazo resin is mixed in the paste to obtain a color resist for producing a color filter, and the transparent substrate is subjected to a well-known photolithography process. A color filter layer is formed on top to produce a desired color filter.

[0023]

According to the inventions of claims 1 and 3, since the dispersant is composed of a mixture of a high molecular weight polymer and a low molecular weight polymer, the crosslink density constituting a part of the dispersant is The action of the high-molecular weight polymer can improve the sensitivity, and the action of the low-molecular weight polymer having a low adhesiveness to the substrate can improve the resolution.

According to the second and third aspects of the present invention, since the dispersing treatment of the pigment is performed by first adding the dispersant composed of the high molecular weight polymer, the above-mentioned high amount adsorbed on the surface of the pigment is high. The adsorption layer composed of the high molecular weight polymer becomes stable and the dispersion stability of the pigment becomes good, and after dispersing the pigment with the above high molecular weight polymer, the dispersant composed of the low molecular weight polymer is added to disperse the pigment. Since the treatment is carried out, even if the pigment concentration is set high, the pigment having the adsorption layer and the low molecular weight polymer do not form a structure in the solution and are difficult to gel, so that the dispersibility in the pigment particles is lowered. Can be prevented.

[0025]

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

Example 1 Average molecular weight 130,000,
Polyvinyl alcohol having a saponification degree of 80% and polyvinyl alcohol having an average molecular weight of 30,000 and a saponification degree of 80% were mixed at a ratio of 1: 1 to prepare a 10% by weight aqueous solution. 100 g of this aqueous solution was mixed with 70 g of water and an interface. 0.2 g of polyoxyethylene oleyl ether as an activator and 30 g of PigmentBlue 15 (copper phthalocyanine) as an organic pigment are added, and glass beads are further added as media to this.
0 g was added and kneaded and dispersed by a sand mill. After the dispersion for 1 hour, this colored paste was centrifuged for 1 hour under the condition of 20,000 g to remove coarse particles.

After adding 0.2 g of diazo resin to the thus obtained coloring paste to prepare a color resist,
This color resist was applied onto a glass substrate, and exposed and developed to form a blue color filter layer.

The sensitivity of the above color resist is 100 m.
It was J / cm ² . The pattern resolution of the color filter layer was 10 μm.

Next, as a comparative example, an average molecular weight of 130,0
When the same experiment as in Example was conducted using only polyvinyl alcohol having a saponification degree of 00 and a saponification degree of 80% as a dispersant, the obtained pattern resolution of the color filter layer was 50 μm.

On the other hand, when the same experiment as in Example was conducted using only polyvinyl alcohol having an average molecular weight of 30,000 and a saponification degree of 80%, the sensitivity of the obtained color resist was 1,000 J / cm ² . there were.

From these results, it is possible to produce a color filter excellent in transparency and color quality by improving dispersibility and sensitivity by constituting a dispersant with a mixture of a high molecular weight polymer and a low molecular weight polymer. confirmed.

Example 2 Average molecular weight 130,000,
A polyvinyl alcohol having a saponification degree of 80% was used to prepare a 10% by weight aqueous solution.
g, 0.2 g of polyoxyethylene oleyl ether as a surfactant, 30 g of Pigment Blue 15 (copper phthalocyanine) as an organic pigment, 250 g of glass beads as a medium were further added, and the mixture was kneaded and dispersed by a sand mill. After the dispersion for 1 hour, 80 g of polyvinyl alcohol having an average molecular weight of 30,000 and a saponification degree of 80% was added to the dispersion, and the mixture was further kneaded and dispersed for 1 hour.

The colored paste thus obtained did not gel, and the average particle size of the pigment was 0.04 μm. Further, the ζ potential on the surface of the pigment, which is one index of the dispersion stability, was measured, and it was a good value of 40 mV.

Next, as a comparative example, an average molecular weight of 130,0
00, 100 g of a 10% by weight aqueous solution of polyvinyl alcohol having a saponification degree of 80%, 250 g of glass beads were added without changing the compounding amounts of water, a surfactant and a pigment, and a kneading / dispersion treatment was carried out for 2 hours. The paste lost fluidity and gelled. The average particle diameter of the pigment at this time was measured and found to be 0.1 μm.

On the other hand, a 10% by weight aqueous solution of polyvinyl alcohol having an average molecular weight of 30,000 and a saponification degree of 80% 100
When 250 g of glass beads was added without changing the compounding amounts of water, surfactant and pigment, kneading and dispersion treatment was performed for 2 hours, this paste did not gel and the average particle diameter of the pigment was Although it was 0.04 μm as in the example, the ζ potential was significantly lowered to 5 mV, and the dispersion stability of the pigment was deteriorated.

From these results, it is possible to disperse the pigment by first adding the dispersant consisting of the high molecular weight polymer and then by adding the dispersant consisting of the low molecular weight polymer. It was confirmed that a colored paste having good dispersion stability without gelation was required even if the value was set high.

As in Example 1, 0.2 g of diazo resin was added to the obtained colored paste to prepare a color resist, and this color resist was applied to the color filter, which was excellent in transparency and color quality. Are manufactured.

[0038]

According to the inventions of claims 1 and 3, the sensitivity is improved by the action of the high molecular weight polymer having a high crosslinking density which constitutes a part of the dispersant, and the adhesiveness to the substrate is improved. It has an effect that resolution can be improved by the action of a small low molecular weight polymer.

According to the second and third aspects of the invention, the dispersion stability of the pigment is improved with the stability of the adsorption layer composed of the high molecular weight polymer adsorbed on the surface of the pigment. The low molecular weight polymer added later and the pigment having the above-mentioned adsorption layer are difficult to gel in the solution, and therefore have the effect of not lowering the dispersibility even when the pigment concentration is set high.

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G03F 7/004 511

Claims (3)

[Claims] 1. A colored paste for a color resist containing a pigment, a surfactant, a dispersant, and a solvent as main components, wherein the dispersant is composed of a mixture of a high molecular weight polymer and a low molecular weight polymer. A colored paste for a color resist, characterized in that 2. A dispersant composed of the above high molecular weight polymer is added to a solvent containing a pigment and a surfactant to disperse the pigment, and then a dispersant composed of the above low molecular weight polymer is added to this solvent. The colored paste for a color resist according to claim 1, wherein the pigment is dispersed. 3. The low molecular weight polymer has an average molecular weight of 5,
000 to 30,000, and the high molecular weight polymer has an average molecular weight of 80,000 to 300,000, The colored paste for color resist according to claim 1 or 2, wherein