JP2850679B2 - Manufacturing method of printing ink - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for producing a printing ink for forming a color filter layer of a liquid crystal display or the like by printing on a glass substrate. The present invention relates to an improved method for producing a printing ink.

[0002]

2. Description of the Related Art A color filter used for a color display liquid crystal display or the like generally has a cross section as shown in FIG. 1, that is, a transparent glass substrate 1 is provided with light transmitted from a portion between pixels. And a color filter layer 3R, 3G, 3B for each color provided in a pixel portion. The light-shielding layer 2 and the color filter layers 3R, 3R
G and 3B are provided with a transparent electrode 4 for applying a voltage to the liquid crystal and driving the liquid crystal.

The above color filter layers 3R, 3G, 3B
Is composed mainly of pigments of each color and a resin component holding these pigments, and various methods for forming these are known. A printing method in which a printing ink containing a pigment and a resin component is printed on the pixel portion to form the printing ink has been widely used.

As a resin component of the printing ink, a thermosetting melamine resin is mainly used because it is necessary to maintain the pixel pattern shape by withstanding the heat at the time of forming the transparent electrode and the heat at the time of assembling the liquid crystal display. In order to maintain and improve the adhesion to the glass substrate as a component, an ink containing a resin composition obtained by further adding an epoxy resin to this melamine resin is used. By heat treatment to a certain degree, the melamine resin and the epoxy resin are cross-linked by ring-opening polymerization, and phthalic acid is involved in the epoxy resin as a curing accelerator, so that the color filter layer 3 has heat resistance and chemical resistance. And the suitability for a transparent electrode.

In producing the printing ink, first, a varnish prepared by dissolving a thermosetting melamine resin in a solvent and a varnish prepared by dissolving an epoxy resin in a solvent are prepared. , A pigment powder is added, a solvent for adjusting viscosity is replenished, and the mixture is sufficiently kneaded with a three-roll mill or the like. Finally, a filter having an opening diameter of 5 to 10 μm is used for 2 to 6 kg / cm from the ink. A method has been adopted in which a solid substance having a particle size larger than the above-mentioned opening diameter is removed by applying an air pressure of about ² and filtering.

[0006]

However, the above-mentioned melamine resin and epoxy resin are hardly dissolved in a solvent and often aggregate in ink to form a solid content. When the pigment is added to the liquid containing the resin component thus aggregated, the pigment adheres to the resin solid component to form a larger solid component, thereby increasing the viscosity of the ink. However, there is a problem that the filtration system is reduced with the increase of the air pressure, and the efficiency of filtration is reduced. For example, it took about 2 hours to filter with a filter having a 5 μm opening diameter (a filter obtained by sintering a stainless mesh).

The present invention has been made in view of such circumstances, and provides a method for efficiently and surely filtering a large amount of ink to produce a high quality printing ink containing no fine solids. The purpose is to do.

[0008]

That SUMMARY OF THE INVENTION The present invention provides menu
In a method for producing a printing ink containing a lamin resin or an epoxy resin or a resin component, a solvent, and a dye as a main component by mixing them, an ink stock solution containing the resin component and a solvent is supplied with an opening diameter of 1 to 5 μm. After removing the solid matter by filtering through a filter having the following, the above-mentioned dye is mixed.

[0009]

According to the present invention, melamine resin or epoxy resin is used.
To remove the solid matter by filtering the ink stock solution containing the resin or the resin component obtained by mixing the resin and the solvent with a filter having an opening diameter of 1 to 5 μm, and then mixing the dye,
No pigment is attached to the resin solids during filtration,
Therefore, it can be filtered easily and efficiently, and
Subsequently, aggregation of the pigment added and mixed can be prevented to produce a high-quality ink containing no fine solids.

[0010]

EXAMPLE A melamine resin varnish was prepared by dissolving 100 parts by weight of a solvent-soluble thermosetting melamine resin in 20 parts by weight of a mixed solvent of ethyl carbitol and butyl cellosolve at a ratio of 1: 1. And this varnish is 3
Use a filter with a pore size of μm (sintered stainless steel mesh), 5kg / c from the top of the ink
Filtration was performed with an air pressure of m ² . On the other hand, 100 parts by weight of the epoxy resin was dissolved in 20 parts by weight of the same solvent to produce a varnish of the epoxy resin, which was filtered in the same manner. It should be noted that in any of the filtrations, the filtration could be performed extremely smoothly and efficiently without causing clogging or the like.

The melamine resin varnish and the epoxy resin varnish were mixed in a weight ratio of melamine resin varnish: epoxy resin varnish = 2: 1. Next, 50 parts by weight of this mixture, 20 parts by weight of pigment and 1 part by weight of phthalic anhydride were mixed, and the above-mentioned solvent was added to adjust the viscosity to 100 poise. After sufficiently kneading with three rolls, the mixture was finally filtered with a sintered filter having an opening diameter of 5 μm.

Using the printing ink thus filtered, as shown in FIG.
A color filter pattern of a liquid crystal display was printed thereon by an intaglio offset method, dried, and heat-treated to completely cure the ink film, thereby forming a color filter layer 3. The obtained color filter layer was uniform and excellent.

[0013]

According to the present invention, the ink can be easily and efficiently filtered, and a high-quality ink free of fine solids can be produced. It is possible to produce a high quality color filter printing ink efficiently and efficiently.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a color filter.

[Explanation of symbols]

 1 Glass substrate. 2 Light shielding film. 3 Color filter layer. 4 Transparent electrode.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C09D 11/10 G02B 5/20

Claims (1)

(57) [Claims] 1. A melamine resin or an epoxy resin or
In the method for producing a printing ink containing a resin component, a solvent, and a pigment as main components by this mixing, a solid material is obtained by filtering an ink stock solution containing the resin component and the solvent through a filter having an opening diameter of 1 to 5 μm. A method for producing a printing ink, comprising mixing the above-mentioned coloring matter after the removal.