JPS61203183A - Printing ink - Google Patents

Abstract

PURPOSE:To provide a printing ink capable of preventing a rapid drying during storage and working on a printing machine and suitable for printing on an absorptive printing material such as paper, which comprises a colorant, a varnish, a solvent and a solvent-soluble polymerizable compound. CONSTITUTION:To 100pts.wt. printing ink comprising 10-40pts.wt. colorant, 50-80pts.wt. varnish and 5-80pts.wt. solvent is added 2-60pts.wt. solvent- soluble polymerizable compound having a polymerizable double bond and selected from among a medium or higher unsaturated fatty acids (or its deriva tive) (e.g.: caproleic acid), a 6-30C aliphatic hydrocarbon (e.g.: undecene) and a vinyl compound (e.g.: vinyl hexyl ether).

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to printing inks, and more specifically, to printing inks that are particularly suitable for printing on absorbent printing materials such as paper and that provide excellent printing workability. Regarding ink.

(Prior Art) Conventionally, various printing inks have been known for imparting designs to various printing materials.

For example, for printing on non-absorbent printing materials such as plastic films, metals, and glass, solvent evaporation printing inks are used that dry by evaporation of the solvent they contain, and absorbent materials such as paper are used. For printing materials, printing inks that dry by absorbing the solvent they contain, such as lithographic printing inks, intaglio printing inks, letterpress printing inks, and silk screen printing inks, are known.

(Problem to be solved by the invention) The various printing inks mentioned above apply a thin film of ink to the surface of a printing plate according to each printing format, and transfer the applied ink to the printing material. Then, the printing ink is set by drying the varnish by evaporation of the solvent, absorption of the solvent, oxidative polymerization of the varnish, etc.

Therefore, it is preferable for these printing inks to dry quickly after transfer, and measures are being taken to do so. However, on the other hand, it is desirable to prevent these printing inks from drying as much as possible during storage or printing. required. In order to adjust these conflicting demands, the drying properties are controlled.

However, although some traditional printing operations may be continuous for long periods of time, most are interrupted occasionally, for example, after completing a day's work, they are then left unattended until the next morning's work. will be done. In such cases, the printing ink is given appropriate drying properties as described above, so the printing ink layer adhering to the printing plate or blanket of the printing press during the interruption will dry on the machine during the interruption. I will do it.

If it dries on the machine in this way, you will not be able to print satisfactorily the next time you start printing, so either remove the printing ink immediately after printing is interrupted, or remove the adhering printing ink before printing starts. It is necessary to remove it.

Such work requires, for example, 1 to 2 hours, during which time printing cannot be performed, and the work requires manpower, making it extremely uneconomical from an industrial perspective.

Therefore, it would be ideal to have a printing ink that does not dry out on the printing press during storage, during preparation before printing, or during printing interruptions, but which nevertheless has a sufficient drying speed on the substrate after printing. , and there is a strong demand for such printing inks. Since these requirements are contradictory, it has not been possible to provide a printing ink having the above-mentioned characteristics in the past.

The inventor of the present invention solved the above-mentioned drawbacks of the conventional technology and, as a result of intensive research in order to meet the above-mentioned demands of the industry, found that when adding a specific compound to a conventional printing ink, especially a polymeric printing ink, It dries very slowly during storage and on the printing press.
Therefore, even if the printing operation is interrupted, for example at night, the printing ink will not dry on the printing machine, so when the next printing starts, there is no need to clean the printing machine and printing can be done immediately, and even though the printing process The present invention was completed based on the finding that printing ink applied on a material can dry sufficiently quickly.

That is, one aspect of the present invention is a printing ink characterized by adding a solvent-soluble polymerizable compound to a printing ink consisting of a colorant, a varnish, and a solvent.

Next, to explain the present invention in more detail, the coloring agent constituting the printing ink of the present invention is a pigment or dye used in conventional printing ink, and the conventionally known pigment or dye is Any of these can be used as is as a coloring agent for ink. In addition, the amount used may be the same as that of conventionally known printing inks.For example, printing ink 1
For example, it generally accounts for about 10 to 40 parts by weight in 00 parts by weight.

Further, as for the varnish constituting the printing ink of the present invention, any conventionally known printing ink varnish can be used as is in the present invention, and the amount used is the same as before, for example, 1°0 parts by weight of the printing ink. In general, it accounts for about 50 to 80 parts by weight.

Preferable varnishes for the printing ink of the present invention are natural or synthetic oxidation-polymerizable resins used in conventional lithographic printing inks, that is, those having polymerizable double bonds in their structure and It polymerizes and hardens with oxygen to form a coating. Many varnishes for these lithographic printing inks are known, and any of these varnishes can be used in the present invention.

The solvent constituting the printing ink of the present invention has a viscosity of the ink,
It is added to correct brightness, flow, etc., and any of the various organic solvents conventionally used for printing ink can be used, and the amount used is:
It generally accounts for about 5 to 80 parts by weight in 100 parts by weight of printing ink. Moreover, such a solvent can also be substituted in whole or in part with a specific polymerizable compound described below.

The solvent-soluble polymerizable compound used in the invention and which mainly characterizes the present invention is used when the printing ink comes into contact with air,
It acts on polymerization initiating radicals generated in the printing ink by heat to eliminate or weaken the effects of those initiating radicals or growing radicals.

Any of the conventionally known solvent-soluble polymerizable compounds having such an effect can be used in the present invention, but those that are particularly suitable for the present invention are liquid in normal state, and are non-volatile to non-volatile in normal state. It is a volatile polymerizable compound.

If these polymerizable compounds are normally liquid or not soluble in solvents, the printing ink dries quickly on the printing press, and if they are volatile, they pose problems in terms of work hygiene, and It becomes difficult to prevent the printing ink from drying too quickly.

In the present invention, when the above polymerizable compounds are added to printing ink, these polymerizable compounds are present in the printing ink during storage of the printing ink or on the printing machine, and these polymerizable compounds are Due to its non-volatility, the polymerization and drying of the printing ink is delayed, thus solving the problems of the prior art as described above.

Furthermore, when the printing ink of the present invention is applied to a printing material,
In particular, when the printing material is an absorbent printing material such as paper, the solvent in the printing ink and the above polymerizable compound dissolved in the solvent are quickly absorbed into the printing material. Therefore, it has been found that the components consisting of the colorant and varnish remaining on the printing material dry quickly like conventional printing inks, and the object of the present invention has been completely achieved.

Therefore, the printing ink of the present invention is particularly useful as an ink for printing absorbent printing materials such as paper, such as lithographic printing.

Furthermore, the above-mentioned solvent-soluble polymerizable compounds may be used in place of the solvent in the printing ink of the present invention, or may be used as part of the solvent, but should not be used in too large a quantity. is not economical and may excessively delay drying after printing, and if the amount used is too small, the effects of the present invention cannot be fully achieved.

According to detailed research by the present inventor, the solvent-soluble polymerizable compound used in the present invention generally accounts for about 2 to 60 parts by weight, more preferably about 2 to 60 parts by weight in 100 parts by weight of the printing ink. The proportion is about 5 to 40 parts by weight, and the purpose of the present invention can be fully achieved at such a proportion.

To explain in more detail about the solvent-soluble polymerizable compound used in the present invention that functions as described above, such a solvent-soluble polymerizable compound has at least one polymerizable double polymer in its structure. It is a compound having a bond, and to give preferable specific examples, the first group includes medium to high unsaturated fatty acids or various derivatives thereof, such as esters, and preferable examples include caproleic acid, undecylenic acid, and elaidine. acids, oleic acid, linoleic acid,
Fatty acids such as lylinic acid, ricinoleic acid, and oxylirusic acid, alcohol esters of these such as methyl, ethyl, propyl, butyl, heptyl, hexyl, octyl, and benzyl esters, mono-triesters of polyhydric alcohols such as ethylene glycol, glycerin, etc. can be mentioned.

The second group includes aliphatic hydrocarbons having about 6 to 30 carbon atoms, and preferred examples include olefins such as nonene, decene, undecene, tridecene, tetradecene, hexadecene, octadecene, nonadecene, and tocodecene; Examples include unsaturated alcohols such as hexenol, heptenol, dodecenol, hexadecenol, oleyl alcohol, lysyl alcohol, and lysyl alcohol, and various esters thereof.

The third group includes various vinyl compounds, and preferred ones include styrene having a C4 to C20 alkyl group or derivatives thereof, vinyl hexyl ether, vinyl hebutyl ether, vinyl octyl ether, and vinyl nonyl ether. , vinyl decyl ether, vinyl lauryl ether, vinyl myristyl ether, vinyl stearyl ether, etc., vinyl oleyl ether, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, (Meth)acrylics such as 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, tetradecyl (meth)acrylate, and hexadecyl (meth)acrylate. Acid esters, vinyl esters such as vinyl caproate, vinyl caprylate, vinyl laurate, vinyl myristate, vinyl stearate, vinyl oleate, allyl esters such as allyl caprate, allyl caproate, allyl myristate, and allyl stearate. etc.

As mentioned above, the above solvent-soluble polymerizable compounds are as follows:
It is preferable to have a molecular weight above a certain level, that is, to have a certain molecular weight that is non-volatile to hardly volatile at room temperature, but not to have a high molecular weight like varnish. If the molecular weight is too high, the solvent-soluble polymerizable compound itself will form an insoluble film. The present invention is intended to explain the invention, and even solvent-soluble polymerizable compounds other than those described above, which have the same functions as those described above, are naturally included in the present invention.

The printing ink of the present invention has the above-mentioned components as essential components, but if necessary, various additives normally used in conventional printing inks can also be used in the printing ink of the present invention. It is possible.

The printing ink of the present invention can be manufactured by any conventionally known manufacturing method, such as kneading with a roll, except that the above-mentioned solvent-soluble polymerizable compound is added to the printing ink.

(Function/Effect) According to the present invention as described above, by adding an appropriate amount of a specific solvent-soluble polymerizable compound to printing ink, it is possible to improve This prevents the printing ink from drying too quickly on the press, so even if a printing operation is interrupted and a considerable period of time has elapsed, the printing ink on the press remains virtually intact and undried before the start of the next print run. Sometimes printing can be started immediately without any cleaning or special preparatory operations. Therefore, various problems of conventional printing presses, such as time-consuming and uneconomical cleaning and uneconomical running-in operation until printing is stabilized, have been solved. Nevertheless, this does not in any way hinder the rapid drying of the printing ink after printing, especially on absorbent printing materials.

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Note that parts in the text are based on weight.

Example 1 225 parts of oxidative polymerization type varnish and 70 parts of tall oil fatty acid benzyl ester (solvent-soluble polymerizable compound) were mixed, and 64.1 parts of the mixture and Brilliant Carmine 8B20 were mixed.
111. 0.8 parts of naphthenic acid mankan and 15.1 parts of 8 stone No. 5 solvent were blended and mixed and kneaded using a Miki roll to obtain a printing ink of the present invention having a tack value of 9.2.

0.15 mJL of this printing ink was spread on art paper using a 4-division RI tester. When the gloss of the color surface of the art paper was measured, it was 73%. On the other hand, when the printing ink was left on an RI tester overnight and then developed in the same way, the gloss was 46%, indicating the excellent storage stability of the printing ink. The time was 4 hours. Furthermore, after performing the above printing ink test, the printing press was left overnight without any cleaning, and when printing was attempted again the next morning, printing was possible without any problems.

Comparative Example 1 225 parts of oxidative polymerization type Fes and 70 parts of No. 865 Solvent were mixed, and 65.3 parts of this mixture, 6820 parts of Brilliant Carmite, 0.8 parts of manganese naphthenate, and 865 parts of Solvent No. 865 were mixed.
A comparative printing ink having a tack value of 9.1 was obtained by mixing and kneading 13.9 parts of the ink (Stone No. 5) in a three-ar.

When this ink was subjected to a color development test in the same manner as in Example 1, the gloss was 74%, but when left overnight on an RI tester, the gloss was 19%, indicating that the storage stability of the printing ink was It was shown that it was insufficient. The drying time of the printing ink on art paper was 4 hours.

In addition, in reprinting after the printing test and after being left overnight, the ink on the printing plate surface dried to form an insoluble film, resulting in poor transfer of the printing ink, and reprinting was impossible as it was.

Examples 2 to 7 Printing inks were prepared in the same manner as in Example 1 except that other polymerizable compounds shown in Table 1 below were used in place of the polymerizable compound in Example 1, and the same tests were performed. , the results shown in Table 1 below were obtained.

List 1 - U 2 Oleic acid [14434 hours 3 Hexadecene 82 35 3 hours M30 minutes 5 Reaction product of linseed oil fatty acid and ethylene glycol - 83453 hours 45 minutes 6 Dodecyl methacrylate 61 38 4 hours 7 Vinyl stearyl ether 82 40 For 3 hours and 15 minutes, the printing inks of Examples 2 to 7 did not dry even after being left on the printing press overnight.

Claims (7)

[Claims] (1) A printing ink comprising a colorant, a varnish, and a solvent, to which a solvent-soluble polymerizable compound is added. (2) The solvent-soluble polymerizable compound is non-volatile at room temperature.
The printing ink according to claim (1), which is hardly volatile. (3) The printing ink according to claim (1), wherein the solvent-soluble polymerizable compound is an unsaturated fatty acid or a derivative thereof. (4) The printing ink according to claim (1), wherein the solvent-soluble polymerizable compound is an aliphatic compound having a polymerizable double bond. (5) The printing ink according to claim (1), wherein the solvent-soluble polymerizable compound is a vinyl compound. (6) The solvent-soluble polymerizable compound has a printing ink of 100%
Printing ink according to claim 1, present in a proportion of about 2 to 60 parts by weight. (7) The printing ink according to claim (1), wherein the solvent-soluble polymerizable compound is liquid at room temperature.