JPS5933369A - Color developing ink - Google Patents

Abstract

PURPOSE:To provide a color developing ink giving developed images of high density, with less fading with time and limited blur of the printed characters, and without developing stains, by incorporating a phenolic resin or an aromatic carboxylic acid (metallic salt) with 10-40C higher linear ether. CONSTITUTION:10-80wt% one or more developers selected from phenolic resins (e.g., p-phenylphenol/formaldehyde resin), and aromatic carboxylic acids or their metallic salts (e.g., zinc 3,5-di-tert-butylsalicylate), 20-200wt% 10-40C higher linear ether (e.g., di-n-amyl ether), and 0-60wt% pigment (e.g., TiO2) are incorporated. EFFECT:Said ink is usable in letterpress or offset printing and excellent in printability, without causing swelling of rubber rolls of a printer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color developing ink. More specifically, the present invention relates to a color-developing ink for carbonless copying paper that reacts with an almost colorless electron-donating dye (hereinafter referred to as a color former) to form a colored image.

Carbonless paper that utilizes a color-forming reaction between an electron-donating coloring agent and an electron-accepting solid acid (hereinafter referred to as a color developer) is already in public use, and generally the color developer is a paper. The entire surface is coated with a water-based color developer, but depending on the purpose, the color developer may be printed and applied only to the necessary parts of the base paper (spot printing and high-quality paper or carbonless paper). (The color developer formulation used for this purpose is called a color developer ink.)

However, most of the color developing inks currently used for spot printing are for flexographic or gravure printing using low boiling point organic solvents, and the use of organic solvents poses safety and hygiene problems. Ta.

On the other hand, JP-A Nos. 51-68307 and 51-68307,
No. 80410, No. 51-94308, No. 54-898
No. 16, No. 54-94910, No. 54-148606
No. 55-38826 discloses a color developing ink for letterpress or offset printing, and is expected to grow in the future due to its advantage of not using low-boiling point organic solvents.

However, these problems occur mainly because the characteristics of the solvent used to dissolve the color developer are not yet sufficient. ■ Insufficient density of the colored image and fading over time; ■ Smearing of the colored image (characters); ■ Printing machine problems. There are problems such as swelling of the rubber roller, ■ Colored stains due to abnormal destruction of microcapsules applied to the upper paper, ■ Poor transfer between the ink mixing rubber rolls during printing, ■ Lifting stains during offset printing, etc. The reality is that a color developing ink that is satisfactory is still not available.

That is, an object of the present invention is to provide a color developing ink which can be printed by a letterpress or offset printing method, has a uniform density of a colored image, has little fading over time, and has little bleeding of colored characters.

As a result of various studies, the inventor of the present invention realized that in order to obtain a good color developing ink, not only the color developer but also the type of solvent is the deciding factor, As a solvent for at least one color developer selected from the group consisting of metal salts, the total number of carbon atoms is 10.
By using a higher chain ether of 40 or less,
It has been found that the above purpose can be achieved.

The color developer used in the present invention is selected from the following.

A. Phenol resin A novolac type phenol resin having a phenolic hydroxyl group, preferable examples include p'-phenylphenol formalin resin, p-cumylphenol formalin resin, p--5ec- or p-1ert- Tylphenol/formalin resin, p-octylphenol/formalin resin, or a cocondensate thereof.

B, aromatic carboxylic acid having one carboxyl group per aromatic nucleus, such as benzoic acid, 4-methyl-3-nitrobenzoic acid, p
-tert-butylbenzoic acid, salicylic acid, 1-hydroxy-2-naphthoic acid, etc., and preferred examples include salicylic acid derivatives, such as 3.5-di-te-
butylsalicylic acid, 3,5-di(α-methylbenzyl)
Salicylic acid, 3-7chlorohexyl-5-(2,2-dimethylbenzyl)salicylic acid, 3-phenyl-5-(2,
2-dimethylbenzyl) salicylic acid and the like.

C1 The above phenolic resin or metal salt of aromatic carboxylic acid.

Examples of metals include calcium, magnesium, zinc, copper, iron, aluminum, and nickel, with zinc being particularly preferred.

In the higher chain ether having a total number of carbon atoms of 10 to 40 used in the color developing ink of the present invention, the two types of alkyl groups connected by an ether bond may be of the same type or different types; It may be linear or branched. Specific representative examples of similar ethers include di-n-amyl ether, di-1so-amyl ether, di-n-octyl ether, 2-ethylhexyl ether, bis(2
-Methyl-4-ethyl amyl ether, di-n-decyl ether, di-n-dodecyl ether (lauryl ether), myristyl ether, cetyl ether.

Examples of different ethers include lauryl methyl ether, lauryl ethyl ether, lauryl ethyl ether, octyl lauryl ether, inamyl cetyl ether, methyl stearyl ether, ethyl stearyl ether, flobyl stearyl ether, etc. It is used either in combination or in a mixture of the two.

If the total number of carbon acids is less than 10, the stability of the ink during printing will be poor, and if it is 41 or more, the compatibility with the color developer will be poor and the ink fluidity will decrease.

The most preferable higher chain ethers from the viewpoint of ink fluidity, stability, and solubility in color developers have a total carbon number of 1.
3 to 24, with a boiling point of about 200°C or higher and a melting point of about 40°C or lower.

Various methods can be considered for producing the color developing ink of the present invention,
Therefore, there are no restrictions on the procedure.

Generally, one or more color developers are dispersed and dissolved in one or more high-grade chain ethers, pigments, adhesives, and additives are added as necessary, and the mixture is ground with three rolls. By doing this, a developer ink is created.

In this case, the color developer in the color developer ink is 10 to 80% by weight.
, preferably 30 to 60% by weight.

The amount of higher chain ether is 20 to 200% of the color developer.
% by weight, preferably from 30 to 100% by weight.

Pigments include inorganic pigments such as titanium oxide, zinc oxide, silicon oxide, calcium carbonate, magnesium carbonate, kaolin, talc acid clay, and organic pigments such as urea/formalin resin and styrene resin. used at a rate of %.

In addition, adhesives include ketone resin, maleic acid resin,
Examples include rosin-modified phenolic resin, nitrocellulose, alkyd resin, etc.

Other additives include antioxidants, ultraviolet absorbers, fluorescent dyes, anti-set-off agents (such as starch, dextrin, and various waxes), and the like.

The amount of developer ink applied to paper during printing is 0.5 to 5 tAI, preferably 1 to 372 tAI as ink.
It's ge.

Examples will be described below, but the present invention is not limited thereto.

In addition, in the examples, parts represent parts by weight.

Example 1 p-phenylphenol-based lumaline resin 50 parts bis(2-ethylhexyl) ether 25 parts (
Boiling point: 269°C, melting point: -95°C) was heated and dissolved, and 25 parts of titanium oxide was added to the mixture.
The mixture was kneaded with a main roll to obtain an ink.

Example 2 p-phenylphenol-formalin m fat 50 parts lauryl methyl needle (liquid at 20°C) 20
20 parts of titanium oxide and 10 parts of calcium carbonate were added to a mixture obtained by heating and dissolving 1 part of the mixture, and the mixture was kneaded with a three-wire roll to obtain an ink.

Example 3 Zinc salt of p-octylphenol-formalin resin 50
Part di-n-lauryl ether (melting point 32°C) 30
10 parts of zinc oxide and 10 parts of titanium oxide were added to a mixture obtained by heating and melting 10 parts of zinc oxide and 10 parts of titanium oxide, and the mixture was kneaded with a three-wire roller to obtain an ink.

Example 4 Zinc 3.5-di-1 crt-putinolyricylate
50 parts bis(2-ethylhexyl)ether)
25 parts of titanium oxide was added to a mixture obtained by heating and dissolving 25 parts of titanium oxide, and the mixture was kneaded with a three-wire roll to obtain an ink.

Comparative Example 1゜Example 1 except that lauryl caprylate was used instead of bis(2-ethylhexyl) ether in Example 1.
An ink was obtained by processing in the same manner as above.

Comparative Example 2゜20 parts of lauryl methyl ether of Example 2 was added to the boat.
Methylphenylxylylmethane (Hysol SAS
, Japan Petrochemical System) except that 30 parts of Example 2 were used.
An ink was obtained by processing in the same manner as above.

Performance Comparison Test Examples 1 to 3, Comparative Example] Fragments of offset printing blankets were immersed in the ink obtained in Examples 1 to 3 and 2 for a day and night, and the degree of swelling was examined.

Next, the inks obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were applied to a letterpress printing machine at 50 far? Is the amount of ink on high-quality paper 1.5 f/n? Spot CF paper was obtained. Layer carbonless paper on this spot CF surface and print with a typewriter (the color density immediately after printing was good in all cases).
We investigated the degree of fading over time and bleeding of colored characters after several months.

These results are shown in Table 1.

Claims (1)

[Claims] 1. A color developing ink characterized by containing at least one member selected from the group consisting of phenolic resins, aromatic carboxylic acids, and metal salts thereof, and a higher chain ether having a total number of carbon atoms of 10 to 40.