JPS59184270A - Printing ink - Google Patents

Abstract

PURPOSE:To provide a printing ink which has excellent levelability and improved thixotropic properties so that no sagging is caused, by mixing particles, an org. binder and a mixture of a good solvent and a poor solvent for said binder in a specified weight ratio. CONSTITUTION:Particles (A) having a particle size of pref. 20mum or below, such as pigment, metallic particles or glass powder, an org. binder (B) such as ethyl- celluloe or acrylic resin, and a solvent mixture (C) obtd. by mixing a good solvent (e.g. butylcarbitol or carbitol acetate) for said binder and a poor solvent (e.g. terpineol or polyethylene glycol) for said binder in a weight ratio of 10/90- 90/10, are mixed together to obtain the desired printing ink. The resulting ink does not cause sagging observed when a good solvent alone is used, nor unevenness of the surface observed when a poor solvent alone is used.

Description

[Detailed description of the invention] The present invention relates to improvements in printing inks.

Conventionally, printing inks have used a good solvent for an organic binder, and the content of particles has been controlled by the content of this good solvent.

When only a good solvent is used, the smoothness of the rough surface, that is, the leveling property is improved, but there is a drawback that the printed pattern sag occurs.

One way to prevent this is to add fine powder such as aerosol to improve thixotropy.9 For example, in printing ink for ceramics, it is important not to change the sintering properties because it adds impurities. There were drawbacks.

The object of the present invention is to provide a printing ink that overcomes these drawbacks.

The inventors of the present invention have conducted intensive studies on methods to resolve the decrease in thixotropy that appears when conventionally using only good solvents, and found that, although the reason is not clear, some of the good solvents were replaced with poor solvents for organic binders. By doing so, the xixotropy can be increased.

It has been found that it is possible to prevent sagging due to xyxothrobby while maintaining leveling properties due to a good solvent.

The present invention consists of particles, an organic binder, and a solvent, and the solvent is a mixed solvent of a good solvent and a poor solvent for the organic binder, and the N amount ratio of the good solvent/poor solvent is 10/90 to 90/10. Concerning a certain printing ink.

Particles in the present invention include pigments, metal particles, inorganic particles such as glass, etc., and are not limited in any way. However, for the purpose of using it in printing ink, the particle size is 20 μm.
The thickness is preferably 10 μm or less, and more preferably 10 μm or less. As the organic binder, ethyl cellulose, butyral resin, acrylic resin, etc. are used, and the amount added is not particularly limited, but it is preferably added in an amount of 0.5 to 20 parts by weight, and 1 to 10 parts by weight per 100 parts by weight of particles. It is more preferable to add part by weight.

In the present invention, a good solvent has a thermodynamic interaction coefficient of 0.
Solvents with a thermodynamic interaction coefficient of 4 to 0.5 and excellent solubility are referred to as butyl carpitol, carpitol acetate, etc., and poor solvents are those with a thermodynamic interaction coefficient of less than 0.3 to 0.4 and excellent solubility Examples of bad solvents include terpineol, polyethylene glycol, and polypropylene glycol. There are no particular restrictions on its boiling point, viscosity, etc., but in view of the need for use in printing ink, the boiling point is preferably 100°C or higher, and more preferably 150°C or higher.

It is desirable that the good solvent and the poor solvent be compatible with each other. It is necessary that the mixing ratio of good solvent and poor solvent, that is, the weight ratio of good solvent/poor solvent, is between 10/90 and 90/10; if it is outside this range, the effect of mixing solvents with different properties will be lost. When the amount of the good solvent exceeds this range, leveling properties are good, but sag is likely to occur after printing due to lack of thixotropy. If the amount of the poor solvent exceeds this range, the xixotropy will be good and no sagging will occur, but the leveling property will be poor and
The unevenness of the printing surface becomes severe.

Although the viscosity of the poor solvent and the good solvent is not particularly limited, it is desirable that the poor solvent has a higher viscosity than the good solvent.

The present invention will be explained below with reference to Examples.

Example 1 100 parts by weight of tungsten particles with an average particle size of 1.8 μm (
(manufactured by Nippon Tungsten ■), 3 parts by weight of ethyl cellulose as an organic binder, and 1.5 parts of phthalate as a plasticizer.
Part M, and a weight ratio of butylcarpitol, which is a good solvent, and terpineol, which is a poor solvent, is 20/8 as a solvent.
A printing ink was obtained by adding 40 parts by weight of a mixed solvent of 0 (butylcarpitol/terpineol) and mixing with 3 nerol.

This was then printed on a ceramic green sheet using a screen with a line-to-line spacing of 100 μm.

When the cross section and surface of the printed product were observed using a stereomicroscope manufactured by Nippon Kogaku, there was no ink dripping and the surface was smooth.

Example 2 The same tungsten particles, organic binder, and plasticizer as in Example 1 were blended in the same amount as in Example 1, and a good solvent and a poor solvent were mixed in a weight ratio of 80/20 (butylcarpitol/terpineol). 35 parts by weight of the mixed solvent prepared above were added and mixed using three rolls to obtain a printing ink.

This was then printed on a ceramic green sheet using a screen with a line-to-line spacing of 100 μm.

When the cross section and surface of the printed product were observed using a stereomicroscope manufactured by Nippon Kogaku, there was no ink dripping and the surface was smooth.

Comparative Example 1 The same tungsten particles, organic binder, and plasticizer as in Example 1 were blended in the same amount as in Example 1, and 35 parts by weight of butyl calpitol was added as a solvent and mixed with three rolls to form a printing ink. Obtained.

Next, this was printed on a ceramic green sheet using a screen with a line spacing of 100 μm from all lines.

When the cross section and surface of the printed product were observed using a stereomicroscope manufactured by Nippon Kogaku, the surface was found to be extremely smooth.

Ink dripping is visible and line-to-line spacing is 100 μn
It becomes narrower from 1 to 20 to 50 μm.

Some short circuits were also observed.

Comparative Example 2 The same tungsten particles, organic binder, and plasticizer as in Example 1 were blended in the same amounts as in Example 1, and 45 parts by weight of terpineol as a solvent was added thereto and mixed with 3 nerol to obtain a printing ink.

This was then printed on a ceramic green sheet using a screen with a line-to-line spacing of 100 μm.

When the cross section and surface of the printed product were observed using a stereomicroscope manufactured by Nippon Kogaku, the surface was not smooth with marks from the screen mesh, and the thickness of the printed lines was uneven.

The printing ink of the present invention consists of particles, an organic binder, and a solvent, and the solvent is a mixed solvent of a good solvent and a poor solvent, and the MM ratio of good solvent/poor solvent is 1°/90 to 90. /1
Since it is set to 0, there is no sag due to only a good solvent, and there is no surface unevenness due only to a poor solvent, and both leveling properties and xyxotrope can be achieved.

Agent: Patent attorney Kunihiko Wakabayashi, -゛111. of

Claims (1)

[Claims] 1. Particles, an organic binder, and a solvent.The solvent is a mixed solvent of a good solvent and a poor solvent for the organic binder, and the weight ratio of good solvent/poor solvent is 10/90 to 90/10. Some printing ink.