JPS6025467B2 - Method for producing coloring agent ink for carbon-free paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing colorant printing inks for carbonless paper.

Conventionally, volatile solvents such as methanol, imbropyl alcohol, or methyl ethyl ketone have been used as printing inks for partial printing of colorants on carbonless paper, but in this case, concentration control, toxicity, flammability, and Due to its low viscosity, its use is limited to gravure printing and flexographic printing, and it cannot be used for letterpress printing or planographic printing.

Conventional color-forming printing inks for carbonless paper use natural solid acids such as activated clay, kaolin, bentonite, and novolac-type acidic polymers as color-forming agents, and light-receiving agents that are dissolved in the above-mentioned low boiling point solvent together with a binder. were mixed and printed on paper using gravure printing or flexo printing. Therefore, since the printing method uses a low boiling point solvent, there are problems such as management to keep the concentration constant, toxicity, flammability, etc., and unavoidable restrictions on the printing method. Color-forming printing inks for planographic printing or letterpress printing have also been devised;
(Japanese Patent Publication No. 49-5930) It was not suitable for printing and the color development was weak, so it was not put to practical use. The present invention significantly improves the above-mentioned drawbacks and provides an excellent carbonless paper that has good printability even in letterpress printing and lithographic printing, has excellent color development, and maintains its sharpness for a long period of time. This makes it possible to produce color printing inks.

The main reason why spot inks for star coloring agents for letterpress and lithographic printing have not been possible until now is that the vehicle envelops the coloring agent, and furthermore, the components of this vehicle may contain substances that inhibit color development. There is. For example, the C=○ bond of glycerides such as vegetable oils and fats inhibits the color development of dyes. Therefore, when these were used, even if the color was developed, the color would quickly fade. In addition, synthetic doji drying oil (Special Publication No. 49-59
When using No. 3P), there was little fading, but the color development did not have sufficient density, and the printability was not good either.
Regarding fading due to substances with this C=○ bond, after developing the color on ordinary carbonless paper, add C on top of it.
It can be determined by coating a substance with =○ bond and observing the change in color.

That is, it is necessary to avoid using substances that show the presence of a C=◯ bond when measured with an infrared spectrophotometer and have an absorption around 1700 skin-1. All vegetable oils and fats have a C=○ bond.

In the method of the present invention, the acidic polymer, which is the coloring agent in carbonless paper, serves as a solvent for mainly novolak phenolic resin and also as a solvent for the coloring agent dye, and is nonvolatile and has good printability. As a result of examining various solvents, it was discovered that inpropylnaphthalenes and diphenylmethanes showed excellent results. The inpropylnaphthalenes are as shown in the following formula, and among these, those of m, {21, {3', and '4' formulas as shown in the following formula are particularly recommended.

These series of compounds can be used alone or in combination, and diphenylmethanes are shown by the following formulas, among which methylphenylxylylmethanes have shown particularly good results. The substance shown in shows extremely good results.

These solvents have been used as solvents for coloring dyes in carbonless paper, but have not been used in the field of ink vehicles.

In fact, the acidic polymer is difficult to dissolve in these solvents at room temperature, but it dissolves and boils when heated.

It was also confirmed that the dissolved acidic polymer did not precipitate even if this solution was cooled to room temperature again. Of course, there are limits to its solubility and precipitation range.
However, by appropriately increasing the viscosity by dissolving the acidic polymer in these solvents, the printability of the ink becomes significantly better, making letterpress and lithographic printing possible. These solutions do not contain substances that inhibit color development, are non-volatile, have moderately high viscosity, and are not known to be toxic, making them ideal as vehicles for letterpress and lithographic printing inks, and do not contain any elements that inhibit color development, so they do not fade. It is possible to keep clear records for a long time without being recognized.

Next, an example will be described.

Example 1 2 kg of KMC-oil (trade name, inpropyl naphthalene, manufactured by Kureha Chemical Co., Ltd.) was heated to 1.5k9 at 100 pm CKM-5254 (trade name, paraphenylphenol formaldehyde resin, manufactured by Showa Union Co., Ltd.). The vehicle was prepared by dissolution.

Add to this 210 g of titanium white as a white pigment (6
%) to make ink.

When this was finished by lithographic printing using a printing machine and printed against commercially available carbonless capsule paper, the color development was strong and no fading was observed even after being left indoors for 30 days. Printability was also extremely good. Drying was quick due to osmosis, and no peeling of the ink from the paper surface was observed.

Example 2 KMC-Oil (trade name, previous generation), lk9 and /-Isol SAS (trade name, methylphenylxylylmethane, manufactured by Nippon Petrochemicals) lk9 were mixed to make CKM-5254 (mentioned above, /volac resin) 2k9. A vehicle is prepared by heating and dissolving at 10℃.

Add to this 240 g of titanium white as a white pigment (6
%) to produce a colored ink for non-carbon paper.
This was finished by planographic printing using a printing machine, and when printed against commercially available carbonless capsule paper, the color development was very clear and no fading was observed even after being left indoors for 30 days. The printability of the same machine as in Example 1 was extremely good.

Printing with the coloring agent ink for carbonless paper produced by the method of the present invention does not require any special printing equipment, can easily perform full-scale printing or partial printing, can reduce costs, and is free from toxicity and flammability. Conventional problems such as quality and density control have also been resolved, and the number of printing operators has therefore been reduced, making the product more stable.

Claims (1)

[Claims] 1. Mixing a pigment with a vehicle obtained by dissolving an acidic polymer in isopropylnaphthalenes or diphenylmethanes, each singly or in a mixture thereof, which can dissolve both the dye for the color former and the acidic polymer for the color former. A method for producing coloring agent ink for carbonless paper, characterized by: