JPH03212465A - Transparent pigment-containing 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, comprising 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) 5-30 pts.wt. compound shown by formula I, (ii) 15-35 pts.wt. compound shown by formula II and (iii) 35-80 pts.wt. compound shown by formula III (R1 to R3 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 a coating material 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. Involved. 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.

<Prior art> The properties required for overcoat materials are (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 Murakami agent, 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).
It lacks. Although silica-based coating materials have heat resistance, they have problems such as being difficult to crank and lacking in 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 agents. Further, by patterning the coating on the substrate, it is possible to obtain color filters with desired pattern shapes classified by color.

The color filter produced in this way is 240°C ~
It exhibits heat resistance (spectral stability) of about 270°C for 1 hour and has excellent characteristics. However, using this upper layer,
There was no satisfactory overcoat material. 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 mentioned 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, it was discovered that heat resistance and transparency could be achieved by highly dispersing transparent pigments in acrylic resin, and the present invention was completed.

<Means for Solving the Problems> That is, the present invention is an acrylic coating material consisting of at least an acrylic resin, a solvent, and a transparent pigment, and optionally a dispersant for dispersing the transparent pigment is added. be.

The monos constituting the acrylic resin used in the present invention are as follows: 1 CNz"C-C0OH (a), cHs=e-coo-■, CHvC-Coo-CHz (Methi37 acrylate)
, n-1 in CHz□e-Coo-CHt-
CHs (Z-37 acrylate), CHt=C at n-3
-COO-CHz-CHs-CHx-CHs (butyl acrylate), (1) When 3 is CH, it represents methyl methacrylate, ethyl methacrylate, butyl methacrylate, and pentyl methacrylate, respectively.

The blending ratio of these monomers is (a) 5 to 30 parts by weight, [
(C) 15 to 35 parts by weight, and 35 to 80 parts by weight of (C), and an acrylic resin of a copolymer of these monomers is used.

In addition, monomers that can slightly change the properties of the resin by adding a small amount when synthesizing an acrylic resin include dimethylamino methacrylate, benzyl acrylate, glycidyl methacrylate, acrylonitrile, and vinyl acetate.

As a solvent, methyl cellosolve, ethyl cellosolve,
Butyl cellosolve, cyclohexanone, xylene, etc. are preferred, and mixtures of these solvents may also be used, but cyclohexanone and ethyl cellosolve are particularly preferred from the viewpoint of solubility and coating properties.

Transparent pigments include palite powder (BaSO4), precipitated barium sulfate (BaSO4), barium carbonate (BaSO4), and barium carbonate (BaSO4).
COz), carbonated lime powder (CaCOz), silica powder (
SjOz), basic magnesium carbonate (MgCO,)
Alumina white (＾Igos・XHzOtHaA1(OH)s), Gl:+7. ．． +'Fi) (A
I (OH) s + BaSO4), Sachin White (C
aSO4+ AI (OH) s), etc.
Indicated by c, r, <color index) number,
10.1B, 19, 20.24.25.26.27, etc.

These transparent 1!11 pigments have a particle size of 50% by weight or more of the total particles of 0.3 μm or less, and 5% of the total particles of the particles of 1 μm or more by weight.
It is preferable from the viewpoint of transparency and dispersibility of the transparent pigment.

If the particles of 0.3 μm or less are less than 50% by weight of the total particles, or if the particles of 1 μm or more are more than 5% by weight, the transparency of the coating material will be poor, especially for overcoat materials for color filters. It is not suitable for applications that require high transparency.

Various surfactants are effective as dispersants for highly dispersing these transparent pigments. Specifically, as cations, acetamine 24, acetamine 86, cortamino 86
P Conch (all product names manufactured by Kao Corporation) include Demol P5 Demol EP, Homogenolt 8, Homogenol Shi-18, Homogenol Shi-95, and Homogenol Shi-95 as anionic products.
There is homogenol L-100 (all product names manufactured by Kao Corporation), and Emaruan A-60 is a nonionic type.
, Rheodor 5P-LIO, Rheodor 5P-510,
Rheodol 5p-oto, Emazol T, -1on,
Emazol 5-20 (all product names manufactured by Kao Corporation)
etc.

Further, when patterning the coating material in the present invention, a photocuring reaction using a photopolymerization method can be used. In the case of photopolymerization, various types of polymers 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-methylbentanediol diacrylate, etc., and polyfunctional monomers include trimethylolpropane acrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl) isocyanate, dipentaerythritol hexaacrylate, etc. There are commercial products available from Showa Kobunshi Co., Ltd., Toagosei Kagaku Kogyo Co., Ltd., Celanese Chemical Co., Ltd., etc. In addition, photopolymerization initiators include acetophenone, benzophenone, benzyl dimethyl ketal, benzoyl peroxide, 2-chlorothioxanthone, etc.; There are commercially available products from Kogyo Co., Ltd., etc. Further, 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 coated and dried.

The method for manufacturing the transparent pigment coating material of the present invention includes: 1) Adding pigment and dispersant to acrylic resin and sufficiently kneading with a stirrer such as a triple roll to make a varnish; 2) Starting photopolymerization of this varnish. 1) Coating the varnish onto the substrate to the required thickness using a roll coater or spin coater; 2) Patterning by partial exposure. and a step of 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.

<Detailed Description of the Invention> In the composition of the present invention, although there is no particular limitation on the composition ratio, the acrylic resin is usually 5 to 30% by weight, the photopolymerizable monomer is 10 to 30% by weight, The photopolymerization initiator is 0.05 to 3% by weight, the transparent pigment is 5 to 30% by weight, and the agglomerate is about 0 to 3% by weight.

When producing a composition based on 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 sill, a ball mill 1, a sand mill, an attritor, or the like. Alternatively, it can be made by dispersing an acrylic resin, a transparent pigment, and a dispersant in advance using a roll mill or the like, and then diluting it with a solvent or acrylic resin varnish. Note that the order of mixing and dispersion is not limited to this, and can be performed as appropriate. In addition, when the composition is to have photopolymerizability, it can be made into a composition that can be patterned by adding a photopolymerizable monomer and a photopolymerization initiator.

The resin composition obtained as described above is coated on a substrate consisting of a transparent substrate (1), a color filter layer (2), etc. as shown in FIG. 1 using a roll coater, a spin coater, etc.
By applying it to an arbitrary thickness, it becomes an overcoat layer (3), which can protect the color filter without impairing the color tone and transparency of the color filter layer (2). 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. To do this, it is efficient to make the overcoat material a photosensitive resin with photocurable properties as described above, expose the area to light while shielding it from light, and develop it with an appropriate solvent. It is. 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> Acrylic resin (20 parts of methacrylic acid, 25 parts of cyclohexyl acrylate, 55 parts of methyl methacrylate was dissolved in 300 parts of ethyl cellosolve, and 0.75 parts of azobisisobutyronitrile was added under a nitrogen atmosphere to give a solution of 70 parts. °C15
Acrylic resin obtained by time reaction)Wol Fat concentration 10
% with ethyl cellosolve.

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 thoroughly kneaded with a main roll to form a transparent varnish. Created.

To this varnish were added 4.0 g of trimethylolpropane triacrylate as a photopolymerizable monomer and 0.8 g of benzyldimethylkecoel as a photopolymerization initiator and stirred well to obtain a transparent composition. After coating the previously created color filter with a spin coater at 1200 rpm for 1 minute,
After drying at C for 20 minutes, approximately 5mm from the color filter frame.
Exposure using a large mask (30m J/cm”
) Shita. Thereafter, it was developed using sodium carbonate (2.5% solution), and the non-exposed areas were removed and thoroughly washed with water. There may be a small amount of transparent pigment remaining on the substrate, so rub it with a soft sponge, wash it with water, and spin dry it for 230 minutes.
The overcoat on the color filter was fixed by baking at °C for 1 hour.

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 colored pigments in acrylic resin, it is difficult to use the overcoat material for this color filter. In contrast, the present invention is an overcoat material for color filters that has excellent heat resistance, and has excellent heat resistance and moisture resistance, and has no cracks. By dispersing it in a resin, it has good adhesion with ITO, and by patterning it, it can be made into an overcoat without impairing its adhesion with a sealant, which is extremely excellent in practice.

[Brief explanation of 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 non-patterned overcoat layer. FIG. 3 is a cross-sectional view showing an example of a filter. (1)...Transparent substrate (2)...Color filter layer (3)...Overcoat layer (4)...End portion Patent applicant Toppan Printing Co., Ltd.

Claims (4)

[Claims] (1) In an acrylic coating material consisting of at least an acrylic resin, a solvent, and a transparent pigment, the main component of the monomer composition of the acrylic resin is ▲a mathematical formula, a chemical formula, a table, etc.▼……(a) ▲a mathematical formula, There are chemical formulas, tables, etc.▼……(b) ▲There are mathematical formulas, chemical formulas, tables, etc.▼……(c) (However, R_1, R_2, R_3 are H or CH_3
, n is an integer from 0 to 4), and its composition ratio is (a) 5
~30 parts by weight, (b) 15-35 parts by weight (c) 35-8
A coating material containing a transparent pigment, characterized in that it uses a copolymer acrylic resin in an amount of 0 parts by weight. (2) The coating material containing a transparent pigment according to claim (1), characterized in that a surfactant is added as a dispersant. (3) A coating material containing a transparent pigment according to claim (1) or (2), wherein the transparent pigment contains barium sulfate as a main component. (4) A method of using a coating material containing a transparent pigment, characterized in that the coating material containing a transparent pigment according to claim (1) is used as an overcoat layer of a color filter.