JP2889624B2 - How to prevent discoloration of printing ink - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a dryer for printing ink, and more specifically, the present invention relates to a hydroquinone, catechol, methylhydroquinone, 4-t-butylcatechol, 2,5-di-t-
Printing attached to the surface of the printing ink in the container or the surface of each part of the printing machine when printing is interrupted without delaying drying on the printing material such as paper, especially when used together with a drying inhibitor such as butyl hydroquinone. Suppress ink drying,
The present invention relates to a printing ink using a printing ink dryer which is effective in delaying and suppressing discoloration of the printing ink during storage.

(Prior art) Various drying inhibitors have been used for the purpose of suppressing and delaying the drying of oxidation polymerization type printing inks such as planographic inks and letterpress inks.
For example, by adding or spraying 1,4-hydroquinone, catechol, methylhydroquinone, 4-tert-butylcatechol, 2,5-di-tert-butylhydroquinone, etc. into the printing ink, the printing ink in the container and the printing are performed. It has been practiced to prevent the printing ink of each part of the printing press from drying out during the interruption.

For example, Japanese Unexamined Patent Publication (Kokai) No. 1-132671 describes that hydroquinone is added or sprayed to a printing ink.

On the other hand, various kinds of metals such as (petroleum acid) metal salts such as naphthenic acid, octylic acid, octenoic acid and neodecanoic acid have been conventionally used to promote drying after printing of oxidative polymerization type printing ink such as planographic ink and letterpress ink. It has been practiced to add a salt dryer into the printing ink.

As described above, in a printing ink which simultaneously contains various drying inhibitors and various metal dryers which are metal salts such as naphthenic acid, octylic acid, octenoic acid, and neodecanoic acid, the printing ink on paper or the like is not suitable. Without delaying drying
Drying of the printing ink on the surface of the printing ink in the container or on the surface of each part of the printing machine when printing is interrupted can be suppressed or delayed. However, if left in an oxygen atmosphere after opening, time will elapse. As a result, the color changes to black, and the color change becomes conspicuous especially in yellow printing ink and medium, which is a problem.

(Problems to be Solved by the Invention) As a result of the study, the present inventors have found that 1,4-hydroquinone,
By using a drying inhibitor such as catechol, methylhydroquinone, 4-tert-butylcatechol, 2,5-di-tert-butylhydroquinone and one or more unsaturated fatty acid metal salts as a metal salt dryer. It has been found that the degree of discoloration of a printing ink such as yellow can be suppressed, and the present invention has been achieved. The present invention improves the above-mentioned various disadvantages and delays drying on a printing medium such as paper. Provided is a printing ink capable of suppressing or delaying the drying of the printing ink adhering to the surface of the printing ink in a container or the surface of each part of the printing machine when printing is interrupted, and suppressing discoloration during storage. Things.

[Configuration of the invention]

(Means for Solving the Problems) The present invention provides a yellow printing ink or a medium ink which is cured by oxidative polymerization, with a quinone-based drying inhibitor of 0.01 to 5%.
The present invention relates to a method for preventing discoloration of a printing ink, characterized by containing 0.1 to 10% by weight of an unsaturated fatty acid metal salt.

Further, the present invention is the method for preventing discoloration of the above printing ink, wherein the metal of the unsaturated fatty acid metal salt is cobalt, manganese, iron, cerium, lead, copper, zinc, zirconium or nickel.

The unsaturated fatty acid metal salt used in the present invention is linoleic acid,
Cobalt, manganese, iron, cerium, lead, copper, zinc, zirconium or nickel salts of unsaturated fatty acids such as oleic acid or linolenic acid.

The unsaturated fatty acid metal salt is added in an amount of 0.1 to 10% by weight, preferably 0.5 to 3% by weight in the printing ink. When the amount is less than 0.1% by weight, the drying property of the printing ink is deteriorated. When the amount exceeds 10% by weight, even if a quinone-based drying inhibitor is used, the printing ink is dried during the production or printing of the printing ink. Would.

The quinone-based drying inhibitors of the present invention include hydroquinone, catechol, methylhydroquinone, 4-tert-butylcatechol, and 2,5-di-tert-butylhydroquinone. These quinone-based drying inhibitors are used in printing inks at 0.01%.
To 5% by weight, preferably 0.04 to 1% by weight.

According to the present invention, it is possible to suppress or delay the drying of the printing ink adhering to the surface of the printing ink in the container or the surface of each part of the printing machine when printing is interrupted without delaying the drying on the printing material such as paper. Even when the printing ink container is left open in an oxygen atmosphere after opening the printing ink container, a printing ink excellent in discoloration resistance can be obtained.

Hereinafter, the present invention will be described with reference to examples. In the examples, “parts” means “parts by weight” and “%” means “% by weight”.

Examples 1-4, Comparative Examples 1-2 76 parts of vehicle mainly composed of rosin-modified phenolic resin and linseed oil, No. 5 solvent (Nippon Oil Co., Ltd.)
2 parts of a 20% hydroquinone / dipropylene glycol monobutyl ether solution and 5 parts of a prototype yellow ink comprising 15 parts of disazo yellow and the unsaturated carboxylic acid, resin acid, and cobalt salt of the present invention shown in Examples 1 to 4. And a sample to which one part of a mixture of manganese salt was added and Comparative Example 1
The cobalt salt and manganese salt of naphthenic acid and the cobalt salt and manganese salt of octyl salt shown in Nos.
For the sample added, the drying time when printing on art paper and the drying time of the ink on the printing press roll,
Table 1 shows the color difference ΔE between the time immediately after sample preparation and the time after standing at 70 ° C. for 90 hours for acceleration.

[Effects of the Invention] According to the present invention, drying of printing ink adhering to the surface of printing ink in a container or the surface of each part of a printing machine when printing is interrupted without delaying drying on a printing material such as paper. It has become possible to obtain a printing ink which has retarded retardation and has no discoloration during storage.

Claims (2)

(57) [Claims] 1. A yellow printing ink or a medium ink which is cured by oxidative polymerization, wherein a quinone-based drying inhibitor 0.01 to 5 is added.
% By weight and 0.1 to 10% by weight of a metal salt of an unsaturated fatty acid. 2. The metal of the unsaturated fatty acid metal salt is cobalt,
The method for preventing discoloration of a printing ink according to claim 1, wherein the method is manganese, iron, cerium, lead, copper, zinc, zirconium or nickel.