JPH03212467A - Acrylic coating material and its use - Google Patents

Abstract

PURPOSE:To obtain the title coating agent capable of being made into a color filter having excellent heat resistance, consisting essentially of a specific acrylic resin, solvent and transparent pigment, by using the coating agent as an overcoat of color filter useful in coloring of liquid crystal display. CONSTITUTION:The objective coating agent consisting essentially of (A) an acrylic resin, a copolymer of (i) 10-30 pts.wt. compound shown by formula I, (ii) 20-40 pts.wt. compound shown by formula II and (iii) 15-60 pts.wt. compound shown by formula III (R1 and R2 are H or CH3; (n) is 0-4), (B) a solvent (preferably cyclohexanone or ethyl cellosolve) and (C) transparent pigment (preferably pigment consisting essentially of barium sulfate). Further, a surfactant is preferably added as a dispersant.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides an acrylic coating that can be used as a protective layer by coating on the upper layer of colored materials such as various heat-resistant inks and various heat-resistant paints. Regarding materials. The present invention also relates to a color filter that can be used as an overcoat for color filters used in colorizing liquid crystal displays to provide color filters with excellent heat resistance.

<Conventional technology> The properties required for overcoat materials include (1) transparency, (2) adhesion to color filters, (3) heat resistance of 240°C or higher, (4) chemical resistance, and (5) ITO (transparent). (6) adhesion with the sealant, etc.

Conventionally, acrylic resin and silica-based inorganic coating materials have been used as overcoat materials provided on the upper layer of color filters. However, as color filters become larger, color filters are required to have a high degree of heat resistance, and acrylic resin has a high heat resistance (190 to 220
°C). Although silica-based coating materials are heat resistant, they tend to crack and lack reliability.

Acrylic resins can have excellent transparency and heat resistance depending on the selection of acrylic monomers.

By adding heat-resistant dyes or heat-resistant pigments to form ink, it is used as heat-resistant paints and various colored coating materials. Furthermore, by coating the substrate and then patterning it, it is possible to obtain color filters with desired pattern shapes that are color-coded for each color.

The color filter produced in this way is heated at 240°C.
It exhibits heat resistance (spectral stability) of about 11 hours at ~270°C, and has excellent characteristics. However, no overcoat material has been found satisfactory for use in this upper layer. Therefore, an object of the present invention is to provide an overcoat material with good heat resistance and transparency.

<Problems to be Solved by the Invention> As described above, a material with good heat resistance and transparency is required as an overcoat material for a color filter. As a result of repeated research on materials that can satisfy transparency and heat resistance, the present inventors discovered that heat resistance and transparency can be satisfied by highly dispersing transparent pigments in acrylic resin. Completed the invention.

Means for Solving the Problems> The present invention is an acrylic coating material containing an acrylic resin, a solvent, and a transparent pigment as main components, and optionally containing a dispersant.

The monomer of the acrylic resin used in the present invention is Ro CH2=C-Coo(aI(Z), 1-C)13 ・-
-----(a) When R1 is H, n=0: Cu2=CCOOC)+3 (methyl acrylate)
At n=1: CH2= CCoo CH2CH3(1-chill7 ri'J) At n=2: CH2=C00-CI(.

CHx CHx (propyl acrylate) When n = 4: When R1 is -CH, methyl methacrylate (n = 0) and ethyl methacrylate (n = 1), respectively
, propyl methacrylate (n=2), butyl methacrylate (n-3), and acrylate (n=4).

z CHx -CCoo CH2CHz OH...pentyl methane) Then, if R2 is H, CHz = CC0N(aHa)z...
... (a) This is N,N dimethylacrylamide, and there are other monomers that can be used in place of it.

In addition, when synthesizing acrylic resins with these compositions, benzyl acrylate, phenyl acrylate, glycidyl methacrylate, acrylonitrile, vinyl acetate, N-vinylpyrrolidone, and tetrahydrofuran are added as seven polymers that can change the properties by adding a small amount. Acrylic resins include frill methacrylate, etc., and these may also be added.
) Obtained by copolymerizing (a). these(
a) (b) The desirable blending ratio of the monomers in (a) is:
(a) 10 to 30 parts by weight, (b) 20 to 40 parts by weight, (
a) 15 to 60 parts by weight.

Examples of suitable containers include methyl cellosolve, ethyl cellosolve, butyl cellosolve, cyclohexanone, xylene, and mixtures of these solvents, but cyclohexanone and ethyl cellosolve are particularly preferred from the viewpoint of solubility and coating properties.

Transparent pigments include palite powder (BaSO, ), precipitated barium sulfate (BaSO, ), barium carbonate (BaCO,
j), carbonate lime powder (aaCO3), silica powder (SiO□
), basic magnesium carbonate (MgCOl), alumina! -(A 1103XH, O also HaA I (
OH)a), Prostophite (A I(OH)i
+B a SO4), Sachin White (aa COJ +
A I (OH)s), etc., but when shown by C, I, (color index) number, it is 10.18.19
．． 20.24.25.26.27 etc.

These transparent pigments should have a particle size of 50% by weight or more of all particles with a diameter of 0.3 μm or less and a particle size of 5% by weight or less with a particle size of 1 μm or more. From the viewpoint of dispersibility, it is preferable that particles of 0.3 μm or less are less than 50% by weight of the total particles, or if particles of 1 μm or more are more than 5% by weight, the transparency of the coating material is poor, especially It cannot be used in applications that require high transparency, such as overcoat materials for color filters.

Various surfactants are effective as dispersants for highly dispersing transparent pigments. Specifically, cationic systems include Acetamine 24, Acetamine 86, and Cortamino 86P Conc (all product names manufactured by Kao Corporation), and anionic systems include Demol P1, Demol EP, Homogenol M-8, and
Homogenol Shi-18, Homogenol L-95, and Homogenol L-100 (all manufactured by Kao Corporation) are available. Non-ionic products include Emaruan A-60, Rheodol 5P-LIO, Rheodol 5P-3IO, and Rheodol. 5p010, Emazol L-10H, Emazol S
-20 (all names of Kao Corporation accessories), etc.

Further, when the coating layer of the coating material of the present invention is partially exposed to light to be photocured and patterned, a crosslinking method or a polymerization method may be used.

When curing by a crosslinking method, various AND compounds can be used as the crosslinking agent added. For example 1, 3
-Bis(4'-Azido benzal)
2-prOpane+ 1, 3 B15(4'
-Azido benzal) -2-propane
2'-5ulfonic acid, 4,
4'-Diazido 5tylbene-22
'-disulfonic acid, etc., but from the viewpoint of solubility, 4, 4'-Diazide 5t
ylb-ene-2,2'-disofonic
When photocuring is carried out by a polymerization method, various types of monomers and polymerization initiators can be used.

Monomers include bifunctional and polyfunctional monomers, and the bifunctional monomers include 1,6-hexanediol diacrylate, ethylene glycol diacrylate, neopentyl glycol diacrylate, triethylene glycol diacrylate, and bis(acryloxyethoxy)bisphenol. A, 3-methylpentanediol acrylate, etc., and polyfunctional monomers include trimethylolprobatone acrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl) isocyanate, dipentaerythritol hexaacrylate, etc. Commercially available monomers are available from Showa Kobunshi Co., Ltd., Toagosei Kagaku Kogyo Co., Ltd., Celaniz Chemical Co., Ltd., and the like. Examples of photopolymerization initiators include acetophenone, penzophenone benzyl dimethyl ketal, hensyl peroxide, and 2-chlorothioxanthone. There are commercially available products from Osaka Organic Chemical Industry Co., Ltd., etc.
In order to improve the adhesion between the substrate and the composition, various commercially available primers may be added to the composition, or the composition may be coated on the substrate in advance after being dried.

The method for manufacturing the transparent pigment coating material of the present invention includes: 1. Adding a pigment and a dispersant to an acrylic resin and thoroughly kneading the mixture with a stirrer such as a triple roll to make a varnish; 2. Adding a crosslinking agent or A process of adding a polymerization initiator and an acrylic monomer and stirring thoroughly; ■ A process of coating 8 varnish on the color fill to the required thickness using a roll coater or spin coater; ■ Patterning by partial exposure. or simply exposing the entire surface to light and then thermally curing it. Here, the acrylic resin is a dispersion medium for the pigment, and the dispersant is an auxiliary agent that uniformly disperses the pigment in the acrylic resin.

<In the composition described in the detailed description of the invention, there is no particular limitation on the composition ratio, but the acrylic resin is usually 5 to 30% by weight, the photopolymerizable monomer is 10 to 30% by weight, and the photopolymerizable monomer is 10 to 30% by weight. The agent is about 0.05 to 3% by weight, the transparent pigment is about 5 to 30% by weight,
The amount of the dispersant is about 0 to 3% by weight.

When a composition is prepared according to the present invention, an acrylic resin, a solvent, a transparent pigment, and a dispersant are dispersed using a dispersion/mixing device such as a roll mill, a ball mill, a sand mill, or a mudriter. Alternatively, it can be made by dispersing the acrylic resin, transparent pigment, and dispersant in advance using a roll mill, etc., and then diluting it with a solvent or embossing varnish.

Note that the order of mixing and dispersion is not limited to this, and can be performed as appropriate. Further, when the composition is to have photopolymerizability, the composition can be patterned by adding a photopolymerizable monomer and a photopolymerization initiator.

The resin composition obtained as described above is coated onto a substrate consisting of a transparent substrate (1), a color filter layer (2), etc. shown in FIG. Overcoat layer (3)
Therefore, the color filter can be protected without impairing the color tone and transparency of the color filter. As for the form of the overcoat layer (3) in FIG. 2, the overcoat layer is removed at the end portion (4) where no overcoat is required, as shown in FIG. In order to do this, it is efficient to make the overcoat material a photosensitive resin with photocurable properties as described above, shield the area to be removed from light, expose it to light, and develop it with an appropriate solvent. It is true. Of course, as shown in FIG. 3, there may also be a form in which an overcoat layer (3) is applied over the entire surface.

The present invention will be specifically explained below using examples. In addition, all compounding ratios in the examples are weight ratios.

<Example 1> Acrylic resin, (hydroxyethyl nucleate 30
(Acrylic resin obtained by dissolving 50 parts of dimethyl acrylate and 20 parts of methyl methacrylate in 300 parts of ethyl cellosolve, adding 0.75 parts of azobisisobutyronitrile under a nitrogen atmosphere, and reacting at 70°C for 5 hours) was diluted with ethyl cellosolve to a resin concentration of 10%.

To 90.8 g of this diluted resin, 9.0 g of Palite powder (barium sulfate) as a transparent pigment and 0.2 g of Emaruan A-60 as a dispersant were added, and the mixture was sufficiently kneaded with three rolls to form a transparent varnish. It was created. In this varnish, 4,4′-diazidostilbene-2,2
Add 1.2 g of '-disulfonic acid and stir well.
A transparent composition was prepared. After coating the previously prepared color filter with a spin coater at 1200 rpm for 1 minute, heat at 70°C.
After drying for 20 minutes, it was exposed to light (300 mJ/cI11) using a mask approximately 5 mm larger than the color filter frame.

Thereafter, it was developed using sodium carbonate (2.5% aqueous solution), and the non-exposed areas were removed and thoroughly washed with water. Since there was a possibility that a small amount of transparent pigment remained on the substrate, the overcoat on the color filter was fixed by rubbing with a soft sponge, washing with water, spin-drying, and beta-betaning at 230° C. for 1 hour.

This color filter had the following properties and exhibited desirable characteristics as a color filter for liquid crystals.

<Example 2> Acrylic resin (30 parts of hydrocutyl methacrylate, 50 parts of dimethyl acrylate, 20 parts of methyl methacrylate) was dissolved in 300 parts of ethyl cellosolve, and 0.75 parts of abbisisobutyronitrile was added under a nitrogen atmosphere. The acrylic resin obtained by reaction at 70°C for 15 hours was diluted with ethyl cellosolve to a resin concentration of 10%.

To 90.8 g of this diluted resin, 9.0 g of halide powder (barium sulfate) as a transparent pigment and 0.2 g of Emaluan A-60 as a dispersant were added, and the mixture was thoroughly kneaded with three rolls to make it transparent. Created a varnish. To this varnish were added 4.0 g of trimethylolpropane triacrylate as a photopolymerizable monomer and 0.8 g of benzyl dimethyl ketal as a photopolymerization initiator, and the mixture was thoroughly stirred to obtain a transparent composition. After coating the previously prepared color filter with a spin coater at 1200 rpm for 1 minute, coat at 70'C for 2 minutes.
After drying for 0 minutes, it was exposed to light (30 mJ/c@'') using a mask that was approximately 5 mm larger than the frame of the color filter.

Thereafter, it was developed using sodium carbonate (2.5% aqueous solution), and the non-exposed areas were removed and thoroughly washed with water. Since a small amount of transparent pigment may remain on the substrate, it was rubbed with a soft sponge, washed with water, spin-dried, and baked at 230° C. for 1 hour to fix the overcoat on the color filter.

This color filter had the following properties and exhibited desirable characteristics as a color filter for liquid crystals.

<Effects of the Invention> Although it is possible to create a color filter with good heat resistance (240'C to 270°C) from a composition obtained by dispersing pigments in acrylic resin, as an overcoat material used for this color filter, It has excellent heat resistance and moisture resistance, and no cracks were observed. In contrast, the present invention is a color filter overcoat material with excellent heat resistance, and by dispersing transparent pigments in highly transparent acrylic resin, the color filter can be coated with heat resistance of 255°C or higher. It has excellent adhesion with ITO and with ITO, and by patterning it can be made into an overcoat without impairing the adhesion with the sealant, making it extremely excellent in practice.

[Brief Description of the Drawings] Fig. 1 is a sectional view showing an example of a color filter, Fig. 2 is a sectional view showing an example of a color filter provided with a patterned overcoat layer, and Fig. 3 is a sectional view showing an example of a color filter provided with a patterned overcoat layer. FIG. 2 is a cross-sectional view showing an example of a color filter provided with an overcoat layer over the entire surface. (1)...Transparent substrate (2)...Color filter layer (3)...Overcoat layer (4)...Edge clearance Applicant Toppan Printing Co., Ltd. Representative Kazuo Suzuki

Claims (4)

[Claims] (1) In the acrylic coating agent, which is characterized by having acrylic resin, solvent, and transparent pigment as its main components, the main components of the monomer composition of the acrylic resin are as follows: (a) ▲Mathematical formula, chemical formula, table, etc. ▼ (b) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (c) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (However, R_1 and R_2 are respectively H or CH_3,
n is an integer of 0 to 4), and the composition ratio is (a) 10 to 30 parts by weight, (b
) 20 to 40 parts by weight, and (c) 15 to 60 parts by weight of an acrylic resin. (2) The acrylic coating material according to claim (1), wherein the transparent pigment contains barium sulfate as a main component. (3) The acrylic coating material according to claim (1), wherein a surfactant is added as a dispersant. (4) A method of using an acrylic coating material, comprising using the acrylic coating material according to claim (1) as an overcoat layer of a color filter.