KR19980064491A - Coating composition - Google Patents

Abstract

Provided is a coating composition suitable for spin coating and useful for forming a protective film such as a color filter capable of forming a transparent protective film having a smooth surface, suitable film thickness and durability.

The present invention provides a coating composition containing at least a carboxyl group and a curing agent, wherein the solvent uses a mixed solvent of propylene glycol monomethyl ether acetate (PGMEA) with a glycol-based compound other than PGMEA, and does not contain PGMEA in the mixed solvent. It relates to a coating composition characterized in that the ratio of the glycol compound is 25 to 99% by weight and the viscosity at 20 ℃ is 15 to 25 centipoise. Preferred glycol compounds other than PGMEA are propylene glycol diacetate, dipropylene glycol methyl ether or propylene glycol-n-butyl ether. Moreover, the copolymer containing acrylic acid or methacrylic acid monomer is mentioned as a polymer containing a carboxyl group, An epoxy type hardening | curing agent is mentioned as a preferable hardening | curing agent.

Description

Coating composition

The present invention relates to a coating composition useful for forming a protective film, and more particularly, to a coating composition useful as a protective film such as a color filter formed on glass or a transparent material and capable of forming a transparent protective film having a smooth surface and durability.

Recently, liquid crystal display devices have been actively used in electronic devices such as AV equipment and personal computers. In particular, color display displays are rapidly increasing in demand due to the good visual confirmation and abundant information. Conventional color filters are used for color display using liquid crystal display devices, and the like, for example, dyeing, printing, or pigment dispersion methods are performed on a transparent substrate such as glass, for example, a mosaic or stripe filter element. And forming by electrodeposition. Color filters are typically manufactured to a thickness of about 1 micron, resulting in a sub-micron stage difference on the surface. This color difference in color STN affects the display quality (eg color unevenness) and it is necessary to suppress the surface flatness below 0.1 micron in order to avoid unevenness in the display. Usually, to obtain a flat surface, a thermosetting acrylic resin is applied to the color filter surface to planarize the surface. In addition, it is not limited to the liquid crystal display device, and even in the solid state imaging device, harsh conditions when the surface of the color filter is treated in a post-production process, for example, immersion treatment of a solvent, an acid, an alkaline solution, and the like, and formation of an electrode layer by sputtering A protective film is provided to protect it from severe conditions such as high temperature generation in the city. As described above, the protective film such as the color filter is smooth, strong and excellent in transparency, and it is required to have no discoloration and deterioration over a long period of time, and to be excellent in heat resistance and chemical resistance. Moreover, such a protective film needs to be a film excellent in adhesiveness with glass and a color filter, and the uniform film thickness must be formed over the whole surface of the glass substrate of a large area. Conventionally, a thermosetting resin containing an epoxy copolymer in addition to the above-mentioned thermosetting acrylic resin (reference: Japanese Patent Application Laid-Open No. Hei 4-114069) as a protective film material of a color filter. 6-212046], which are not sufficient to meet all the requirements of these requirements.

On the other hand, the viscosity of the solution conventionally used as a protective film agent, such as a color filter, is about 20 cps because the coating property is good at around 20 centipoise (cp) when spin coating. Moreover, since the color filter is 1-1.5 micrometers, the film thickness of a protective film needs a thickness of 2-2.5 micrometers. Therefore, the viscosity of the conventional coating composition is adjusted to about 20 cps and the solid film concentration can be obtained at the same time, and the known propylene glycol monomethyl ether acetate (PGMEA) as a safety solvent is used alone as a solvent. In this case, since the viscosity of PGMEA is slightly low at 1.1 cp, it is necessary to increase the solid content in order to obtain the desired viscosity. And since the film thickness after application | coating mainly depends on solid content concentration, when it considers applicability | paintability, the film thickness of the protective film formed will be out of a desired range. For example, in the case of forming a protective film using PGMEA alone as a solvent of the protective film agent OCL3 manufactured by Hoechst, it is difficult to obtain a desired film thickness under current spin coating conditions. When PGMEA is used alone as a solvent, there are methods to increase the viscosity by increasing the molecular weight of the polymer component, and as the molecular weight increases, coating properties deteriorate, problems such as streaks and dropping of dyes occur, and are not suitable as a protective film. In addition, the PGMEA has a high vapor pressure of 3.7 mmHg / 20 ° C., and a phenomenon of evaporation of the solvent occurs during spin coating, and it is difficult to obtain a uniform coating film.

The present invention has a characteristic that satisfies the flatness and adhesion to the color filter, which is an important characteristic in the coating composition without defects, in particular, radiation curable and thermosetting protective film, and also has the applicability and the film thickness of the protective film formed It is an object of the present invention to provide a coating composition that satisfies and to provide a coating composition suitable for forming a protective film of a color filter using a spin coating method.

MEANS TO SOLVE THE PROBLEM As a result of earnestly research, the present inventors discovered that the above-mentioned conventional subject can be solved by using the following coating composition, and completed this invention.

That is, the coating composition of the present invention is a coating composition containing at least a carboxyl group and a curing agent, wherein the solvent consists of a mixed solvent of propylene glycol monomethyl ether acetate (PGMEA) with a glycol-based compound other than PGMEA and mixed The proportion of glycol compounds other than PGMEA in the solvent is 25 to 99% by weight, and the viscosity at 20 ° C is 15 to 25 centipoise.

The present invention is described in more detail below.

solvent

In the present invention, a mixed solvent of propylene glycol monomethyl ether ester (PGMEA) and one or more glycol-based compounds other than PGMEA is used as the solvent of the coating composition. PGMEA, which is one component of the mixed solvent, is used as a solvent for a resist, as described above. It is known as a general purpose and high safety solvent.

Moreover, as long as glycol-type compounds other than PGMEA which comprise components other than a mixed solvent, glycol type compounds other than PGMEA, all are satisfactory. As said glycol type compound, the propylene glycol type compound of following General formula (1) is mentioned, for example.

R ¹ -O- [CH ₂ CH (CH ₃ ) O] nR ²

In Chemical Formula 1,

n is 1 or 2,

R ¹ and R ² are hydrogen atoms, alkyl groups of 2 to 5 carbon atoms, phenyl groups or acetyl, and R ¹ and R ² are not hydrogen atoms at the same time, and when one of R ¹ and R ² is a methyl group, the other is not an acetyl group.

As the propylene glycol compound of the formula (1), for example, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol-n-butyl ether (PnB), propylene glycol tert-butyl ether, propylene glycol Phenyl ether, dipropylene glycol methyl ether (DPM), dipropylene glycol propyl ether, tripropylene glycol methyl ether, propylene glycol ethyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol diacetate (PGDA) and the like.

As glycol compounds other than the propylene glycol compound, ethylene glycol ethyl ether, ethylene glycol methyl ether, ethylene glycol isopropyl ether, ethylene glycol tert-butyl ether, ethylene glycol-n-butyl ether, diethylene glycol methyl ether And ethylene glycol compounds such as diethylene glycol ethyl ether, diethylene glycol butyl ether, triethylene glycol butyl ether, and the like 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutanol, and the like. . However, the present invention is not limited to these specifically illustrated compounds.

Among them, those having higher viscosity and boiling point than PGMEA and having high stability are preferable. In particular, propylene glycol diacetate (PGDA) and dipropylene glycol methyl in terms of safety, coatability, film formability, viscosity of coating composition, film thickness of formed film, etc. Preference is given to ether (DPM), propylene glycol-n-butylether (PnB), of which PGDA is particularly preferred.

These glycol compounds other than PGMEA can be used individually or in combination of 2 or more. Moreover, it is preferable that the ratio of glycol compounds other than PGMEA in a mixed solvent shall be 25 to 99 weight%. This is because when the ratio of the glycol compound other than PGMEA is less than 25% by weight, a problem occurs in that a desired protective film is not obtained. Moreover, although the ratio of glycol compounds other than PGMEA differs according to the specific glycol compound used, generally the range of 25 to 75 weight% is preferable.

Polymers containing at least carboxyl groups

On the other hand, the coating composition of the present invention contains at least a polymer containing a carboxyl group and a curing agent. Of these, any polymer containing at least a carboxyl group is preferred as long as it contains a carboxyl group in the polymer, and a copolymer containing an acrylic acid or methacrylic acid monomer is preferable. Comonomers that can be used with acrylic acid or methacrylic acid monomers in copolymers containing acrylic acid or methacrylic acid monomers can be used as long as they are conventionally used as comonomers of acrylic acid or methacrylic acid copolymers. Preference is given to esters of methacrylic acid. Examples of (meth) acrylic acid- (meth) acrylic acid ester copolymers include poly (methacrylic acid-CO-methyl methacrylate), poly (methacrylic acid-CO-methyl acrylate), and poly (methacrylic acid-CO-acrylic acid Butyl), poly (acrylic acid-CO-methyl methacrylate), poly (acrylic acid-CO-methyl acrylate), poly (methacrylic acid-CO-benzyl methacrylate), poly (methacrylic acid-CO-hydroxymeta Acrylate) etc. are mentioned.

In addition, the polymer containing a carboxyl group in this invention includes the polymer containing an unsaturated bond which can superpose | polymerize in a molecule | numerator. Polymers containing such carboxyl groups and polymerizable unsaturated bonds include reaction products in which a portion of the carboxyl groups of the copolymer reacts with a compound in the molecule containing an unsaturated bond capable of polymerization. As a compound containing an unsaturated group which can polymerize in a molecule capable of reacting with a carboxyl group, glycidyl (meth) acrylate, allyl glycidyl ether, (3,4-epoxycyclohexyl) methyl acrylate or (3, Epoxy acrylate or epoxy methacrylate, such as 4-epoxycyclohexyl) methyl methacrylate, is mentioned as a preferable thing.

Hardener

In addition, as long as it hardens the polymer containing a carboxyl group as a hardening | curing agent of the composition of this invention, any thing can be used, and various things, such as an epoxy type hardening agent, an isocyanate type hardening | curing agent, and a vinyl type hardening | curing agent, can be used. An epoxy type hardening | curing agent is mentioned as a preferable hardening | curing agent. Specific examples of the epoxy curing agent include adipic acid diglycidyl ester, glycerol-α, α'-diglycidyl ether, glycerol tridiglycidyl ether, trimethylolpropane diglycidyl ether, and trimethylolpropane triglycidyl Ether, poly (oxyethylene) -α, ω- diglycidyl ether, ethylene glycol diglycidyl ether, poly (oxypropylene) -α, ω- diglycidyl ether, propylene glycol diglycidyl ether, Poly (oxytetramethylene) -α, ω- diglycidyl ether, alkyl diglycidyl ether, poly (oxyethylene) -α-lauryl-ω-glycidyl ether, sorbitol tetraglycidyl ether, sorbent Aliphatic polyhydric alcohol polyglycidyl ether, such as a nontriglycerideglycidyl ether, tetraglycerol tetraglycidyl ether, hexaglycerol tetraglycidyl ether, pentaerythritol tetradiglycidyl ether, and diglycerol triglycidyl ether, It may be mentioned as a preferred ester.

Random ingredient

The coating composition of the present invention may be thermoset and radiation curable. And various known additives known to be used in thermosetting or radiation curable compositions, such as polymerization initiators, sensitizers, fluorine-based compounds or silicone resins such as stabilizers, antioxidants, etc., if necessary. Can be. In addition, in order to improve the physical properties of the formed protective film, a polymer containing no carboxyl group, a polymerizable monomer, a crosslinking agent, and the like may be added, and an adhesive improving agent such as mercaptopropyltrimethoxysilane may be added to improve the adhesiveness of the protective film. It can be contained. In addition, various kinds of polymerization initiators are known, and in the case of a radiation curable composition, halomethyloxazole-based compounds such as 2-trimethyl-5-styryl-1,3,4-oxadiazole, 2,4-bis (trichloro Halomethyl-s-triazine compounds such as methyl) -6-p-methoxystyryl-s-triazine, benzoin ethers such as benzoin methyl ether, acetophenone or derivatives thereof, sulfonium salts, iodonium, dia Onium salts, such as a zonium salt, etc. can be used.

Viscosity

The viscosity of the coating composition in the present invention is 15 to 25 centipoise (cp) at 20 ° C., which is in accordance with the good applicability in this range in the spin coating method as described above. The viscosity of the coating composition is more preferably 18 to 22 cps.

Solids concentration

In the present invention, it was again found that the concentration of solids in the composition is important in terms of the film thickness formed and the adhesion of the film. Solids concentration in the composition is generally 16 to 21% by weight, more preferably 17 to 20% by weight. In the case where the solid concentration is less than 16% by weight or more than 21% by weight, an appropriate membrane may not be obtained and at the same time when the content exceeds 21% by weight, adhesion may be undesirable.

Example

The present invention will be described in more detail based on Examples, and the present invention is not limited to these Examples.

Example 1

The following compositions are prepared as thermosetting coating compositions.

Methacrylic acid-methyl methacrylate (30:70)

Glycidyl methacrylate of copolymer (molecular weight about 25,000)

94 g of adjuncts

5 g of 1,6-hexanediol diglycidyl ether

Mercaptopropyltrimethoxysilane 1 g

To the above composition, a mixed solvent consisting of 50% by weight of propylene glycol methylether acetate (PGMEA) and 50% by weight of propylene glycol diacetate (PGDA) was added and the coating composition containing 18% by weight of the non-solvent component was adjusted. do. The viscosity of the resulting solution is 19.4 cps. Each of these compositions was applied on a substrate on which a 1.2 μm color filter was formed under a spin coating condition of 1000 rpm / 5 seconds, followed by drying for 1 minute at 100 ° C. on a heating plate, followed by thermosetting for 20 minutes on a 230 ° C. heating plate. The average film thickness of the protective film pattern thus formed was 2.3 탆 and the standard deviation of the film thickness was 0.02 탆. The flatness was high, and the adhesiveness showed durability of 6 hours or more in an environmental test of 120 ° C./100% humidity. It is also excellent in wear resistance, fouling resistance and chemical resistance.

Example 2

The following composition is prepared as the photosensitive coating composition.

Methacrylic acid-methyl methacrylate (30:70)

Glycidyl methacrylate of copolymer (molecular weight about 25,000)

91 g of adjuncts

5 g of 2,4-bis (trichloromethyl) -6-styryl-s-triazine

3 g of 1,6-hexanediol diglycidyl ether

γ-mercaptopropyltrimethoxysilane 1 g

A mixed solvent consisting of 50% by weight of propylene glycol methylether acetate and 50% by weight of propylene glycol diacetate (PGDA) as the solvent is added to the above-mentioned composition, and the coating composition containing 18% by weight of the above non-solvent component is adjusted. Each of these compositions was applied on a substrate forming a color filter of 1.2 mu m under spin coating conditions of 1000 rpm / 5 seconds, followed by drying at 100 DEG C for 1 minute on a heating plate, and then interposing a predetermined mask at a distance of about 100 mu m. Proper exposure to 120 mJ / cm ^{2 with} a high pressure mercury lamp. Subsequently, the pattern-exposed photosensitive coating layer was developed with 0.05 N potassium hydroxide to obtain a pattern. Then it is thermosetted on a heating plate at 230 ° C. for 20 minutes. The average film thickness of the protective film pattern thus formed was 2.3 탆 and the standard deviation of the film thickness was 0.02 탆. The flatness was high, and the adhesiveness showed durability of 6 hours or more in an environmental test of 120 ° C./100% humidity. In addition, these patterns are also excellent in wear resistance, fouling resistance and chemical resistance.

Example 3

In the coating composition of Example 2, a coating composition containing 50% by weight of PGMEA and 50% by weight of DPM (dipropylene glycol methyl ether) as a solvent and containing 17.0% by weight of a non-solvent component is adjusted. This composition exhibits a viscosity of 19 cps. Each of these coating compositions was applied on a substrate forming a color filter of 1.2 μm under a spin coating condition of 1000 rpm / 5 seconds, followed by drying at 100 ° C. for 1 minute on a heating plate, and then a predetermined distance of about 100 μm from the photosensitive coating layer. A high-pressure mercury lamp is used to expose 120 mJ / cm ² of PROXIMITY through a mask. Subsequently, the pattern-exposed photosensitive coating layer was developed with 0.05 N potassium hydroxide to obtain a pattern. Then it is thermosetted on a heating plate at 230 ° C. for 20 minutes. The average film thickness of the protective film pattern thus formed was 2.34 µm and the standard deviation of the film thickness was 0.03 µm. The flatness was high, and the adhesiveness showed durability of 6 hours or more in an environmental test of 120 ° C / 100% humidity. In addition, these patterns are also excellent in wear resistance, fouling resistance and chemical resistance.

Example 4

In the composition of Example 1, the mixed solvent which consists of 50 weight% of PGMEA and 50 weight% of DPM is used as a solvent, and the composition which contains 17.8 weight% of non-solvent components is adjusted. The viscosity of this coating composition is 19.4 cps. Each of these compositions was applied on a substrate on which a 1.2 μm color filter was formed under spin coating conditions of 1000 rpm / 5 seconds, and then dried at 100 ° C. on a heating plate for 1 minute. Then it is thermosetted on a heating plate at 230 ° C. for 20 minutes. The average film thickness of the protective film pattern thus formed was 2.34 μm, and the standard deviation of the film thickness was 0.02 μm. The flatness was high, and the adhesiveness showed durability for 6 hours or more in an environmental test of 120 ° C./100% humidity. In addition, it is also excellent in wear resistance, fouling resistance and chemical resistance.

Example 5

In the composition of Example 2, 25 wt% of PGMEA and 75 wt% of PnB (propylene glycol-n-butylether) are used as a solvent, and a composition containing 18 wt% of the non-solvent component is adjusted. This composition exhibits a viscosity of 19.8 cps. These compositions were each applied on a spin coating condition of 1000 rpm / 5 seconds on a substrate forming a color filter of 1.2 μm, and then dried at 100 ° C. for 1 minute on a heating plate. PROXIMITY exposure of 120 mJ / cm <^2> is performed with a high pressure mercury lamp through the predetermined mask which spaced the said photosensitive coating layer about 100 micrometers. Subsequently, the pattern-exposed photosensitive coating layer was developed with 0.05 N potassium hydroxide to obtain a pattern. Then it is thermosetted on a heating plate at 230 ° C. for 20 minutes. The average film thickness of the protective film pattern thus formed was 2.46 μm, and the standard deviation of the film thickness was 0.03 μm. The flatness was high, and the adhesiveness also showed durability for 6 hours or more in an environmental test at 120 ° C./100% humidity. In addition, these patterns are also excellent in wear resistance, fouling resistance and chemical resistance.

Example 6

In the composition of Example 1, 25 wt% of PGMEA and 75 wt% of PnB as a solvent are used, and a composition containing 17.6 wt% of the non-solvent component is adjusted. The viscosity of this coating composition is 19.6 cps. Each of these compositions was applied on a substrate on which a 1.2 μm color filter was formed under a spin coating condition of 1000 rpm / 5 seconds, followed by drying for 1 minute at 100 ° C. on a heating plate, followed by thermosetting for 20 minutes on a 230 ° C. heating plate. The average film thickness of the protective film pattern thus formed was 2.32 μm, and the standard deviation of the film thickness was 0.02 μm. The flatness was high, and the adhesiveness showed durability of 6 hours or more in an environmental test at 120 ° C./100% humidity. This pattern is also excellent in wear resistance, fouling resistance and chemical resistance.

Example 7

In the coating composition of Example 2, 50 wt% of PGMEA, 37.5 wt% of PGDA, and 12.5 wt% of PnB were used as a solvent, and a coating composition containing 17.8 wt% of the non-solvent component was adjusted. This composition exhibits a viscosity of 17.5 cps. Each of these coating compositions was applied on a substrate forming a color filter of 1.2 μm under a spin coating condition of 1000 rpm / 5 seconds, followed by drying at 100 ° C. for 1 minute on a heating plate, and then a predetermined distance of about 100 μm from the photosensitive coating layer. A high-pressure mercury lamp is used to expose 120 mJ / cm ² of PROXIMITY through a mask. Subsequently, the pattern-exposed photosensitive coating layer was developed with 0.05 N potassium hydroxide to obtain a pattern. Then it is thermosetted on a heating plate at 230 ° C. for 20 minutes. The average film thickness of the protective film pattern thus formed was 2.49 µm, and the standard deviation of the film thickness was 0.03 µm. The flatness was high, and the adhesion showed durability of 6 hours or more in an environmental test of 120 ° C / 100% humidity. In addition, these patterns are also excellent in wear resistance, fouling resistance and chemical resistance.

Example 8

In the composition of Example 1, a mixed solvent consisting of 50% by weight of PGMEA, 37.5% by weight of PGDA, and 12.5% by weight of PnB was used as a solvent, and a composition containing 17.8% by weight of a non-solvent component was adjusted. The viscosity of this coating composition is 19 cps. Each of these compositions was applied on a substrate on which a 1.2 μm color filter was formed under a spin coating condition of 1000 rpm / 5 seconds, then dried at 100 ° C. for 1 minute on a heating plate, and then thermally cured for 20 minutes on a 230 ° C. heating plate. . The average film thickness of the protective film pattern thus formed was 2.46 μm, and the standard deviation of the film thickness was 0.02 μm. The flatness was high, and the adhesiveness showed durability of 6 hours or more in an environmental test of 120 ° C./100% humidity. In addition, it is also excellent in wear resistance, fouling resistance and chemical resistance.

Comparative Example

A coating composition having a viscosity of 19.9 cps was prepared using OCL3 manufactured by Hoechst as a coating material and PGMEA as a solvent. The non-solvent component concentration of this composition is 21.5% by weight. Each of these compositions was applied on a substrate on which a 1.2 μm color filter was formed under a spin coating condition of 1000 rpm / 5 seconds, then dried at 100 ° C. for 1 minute on a heating plate, and then thermally cured for 20 minutes on a 230 ° C. heating plate. The average film thickness of the protective film pattern thus formed is 2 탆, and the film thickness standard deviation is 0.04 to 0.05 탆, and the film thickness is not only thick but also the film uniformity is inferior.

As described above, the coating composition of the present invention has excellent coating properties when applied by the spin coating method, and the film formed by coating has a uniform film thickness and excellent flatness and is used as a protective film for color filters. In addition, it is possible to form a protective film having a desired film thickness and is excellent in adhesion, durability and transparency with transparent substrates such as glass and color filter layers, and is particularly preferred as a composition for forming a protective film for color filters used in liquid crystal display devices and the like.

Claims (7)

A coating composition containing at least a carboxyl group-containing polymer and a curing agent, wherein the solvent consists of a mixed solvent of propylene glycol monomethyl ether acetate (PGMEA) with a glycol-based compound other than one or more propylene glycol monomethyl ether acetates, The composition of the glycol-based compound other than PGMEA is 25 to 99% by weight and the viscosity at 20 ℃ is 15 to 25 centipoise. The coating composition according to claim 1, wherein the solid concentration is 16 to 21% by weight. The coating composition according to claim 1 or 2, wherein the glycol compound other than propylene glycol monomethyl ether acetate is a propylene glycol compound. The coating composition of claim 3, wherein the propylene glycol compound is a compound of Formula 1. Formula 1 R ¹ -O- [CH ₂ CH (CH ₃ ) O] nR ² In Chemical Formula 1, n is 1 or 2, R ¹ and R ² are hydrogen atoms, alkyl groups of 2 to 5 carbon atoms, phenyl groups or acetyl, and R ¹ and R ² are not hydrogen atoms at the same time, and when one of R ¹ and R ² is a methyl group, the other is not an acetyl group. . The coating composition according to claim 4, wherein the propylene glycol compound of formula 1 is propylene glycol diacetate. The coating composition according to claim 4, wherein the propylene glycol compound of formula 1 is dipropylene glycol methyl ether. The coating composition according to claim 4, wherein the propylene glycol compound of formula 1 is propylene glycol-n-butyl ether.