JPH01292077A - Dry lithography ink - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] "Purpose of invention" (Industrial application field) The present invention relates to a dry lithographic printing ink.

(Prior art) Currently, there are letterpress printing, lithographic printing, intaglio printing, etc. as general printing methods. Among lithographic printing, in wet offset printing, the printing plate surface consists of a parent wood part and an oleophilic part, and the ink is This is a method that transfers only to the lipophilic area and yields two lines. This printing method is characterized by the fact that images are clear, high-quality printed matter can be obtained, plate making costs are low, and plate making can be done in a short time. However, this printing method uses dampening water along with ink during printing, so it is necessary to control the dampening water as well as the ink.

Printing work requires advanced technology. For this reason, printing methods that allow lithographic offset printing without using dampening water have recently been proposed. In other words, it is dry lithographic printing, and printing with this method does not suffer from the problems caused by dampening water, which was a problem with conventional wet offset printing.

For example, printing ink emulsification and poor transfer due to water loss.

The occurrence of ghosting etc. is improved.

However, if printing is continued for a long time using this dry lithography method using ordinary ink, the temperature on one plate surface will rise, and the ink will easily adhere to non-image areas, causing stains. As a means to solve this problem, a method has been proposed in which various ink materials are modified with silicon compounds. for example,
Silicon modified alkyd resin (Special Publication No. 51-10124
No. 51-22405 (91 ft), silicone-modified phenolic resin (Japanese Patent Publication No. 1982-10042, Japanese Patent Application Publication No. 52-62506), silicone-modified drying oil (Japanese Patent Publication No. 52-10041, Japanese Patent Application Publication No. 1982-1952) -100
No. 42) Silicon-modified cyclopentadiene resin (
JP-A-56-11024, JP-A No. 56-110706
Publication No.).

There is an ink using a solvent containing a low aromatic olefin component (Japanese Patent Application Laid-open No. 82861/1983). Although these materials are effective against stains, their stain resistance may still be unsatisfactory depending on the combination.

While the background smudge resistance is improved, the gloss of the printed matter is deteriorated, resulting in a decrease in the quality of the printed matter. On the other hand, the problem with ink is that the ink thickens during storage, resulting in poor workability. Furthermore, since siloxane compounds are much more expensive than general ink materials, they have the disadvantage of increasing the price of the ink.

(Problems to be Solved by the Invention) In printing using dry planography, there has been a desire for a dry planographic printing ink that is resistant to scumming, has excellent gloss, is inexpensive, and has excellent stability during storage.

"Structure of the Invention" (Means for Solving the Problems) The present inventors investigated a dry lithographic printing ink that is resistant to scumming, has excellent gloss and storage stability, and is inexpensive. and phenols in the presence of an acid catalyst. If necessary, an alkylphenol containing an alkyl group having 4 to 12 carbon atoms is mixed with the reaction product obtained by heating and reacting the compounds and phenols in the presence of formaldehyde and an acid catalyst. A rosin-modified phenol resin consisting of a reaction product obtained by reacting to form a novolac body, and then esterifying the novolac body using a polyhydric alcohol in a range not exceeding 10% by weight based on the novolac body. The resin used in the printing ink of the present invention, which led to the invention of the dry lithographic printing ink containing it as a varnish component, is a specific rosin.
to the phenol reactant (hereinafter referred to as intermediate).

If necessary, an alkylphenol containing an alkyl group having 4 to 2 carbon atoms is mixed and subjected to a so-called novolak reaction in the presence of diformaldehyde and an acid catalyst.

Next, a specific phenol-modified rosin resin obtained by subjecting this to an esterification reaction becomes an excellent resin for printing ink that meets this purpose.

In the present invention, there is an intermediate obtained by subjecting rosins and phenols to a heating reaction in the presence of an acid catalyst. Here, rosin refers to gum rosin, wood rosin, polymerized rosin, tall oil rosin, disproportionated rosin, polymerized rosin, and the like. As phenols.

Carbolic acid and cresol are preferred. As acid catalysts, 7 p-toluenesulfonic acid, dodecylbenzenesulfonic acid,
Methanesulfonic acid, ethanesulfonic acid, sulfuric acid.

Preferred are hydrochloric acid, boron trifluoride, anhydrous aluminum chloride, and the like.

The alkylphenols used when converting the intermediate into a novolak have an alkyl group having 4 to 12 carbon atoms.
There are various alkylphenols preferably having 4 to 9 alkylphenols, and specific examples include butylphenol, amylphenol, octylphenol, nonylphenol, dodecylphenol, and the like. The amount of the alkylphenol to be used is not particularly limited, but is determined by considering the gloss and solubility of the resulting printing ink resin, and is usually 0 to 100 parts by weight, preferably 1 part by weight, based on 100 parts by weight.
It may be in the range of 5 to 65 parts by weight. If it exceeds 100 parts by weight, the softening point of the resulting printing ink resin will drop significantly, which is not preferable.

Formaldehyde is an essential component for converting the intermediate into a novolak-type phenol-modified rosin resin.

Formaldehyde herein means a formaldehyde supply substance, and formaldehyde and paraformaldehyde can be exemplified.

Next, the novolak body is subjected to an esterification step to form the resin for printing ink of the present invention. Here, the esterification step refers to the process that occurs between the carboxyl group derived from rosin and the phenolic hydroxyl group derived from phenol present in the novolac body, when a polyhydric alcohol is not used for the novolak body. Refers to a dehydration reaction. On the other hand, when a polyhydric alcohol is used for the novolac compound, not only the above dehydration reaction but also the dehydration reaction between the carboxyl group derived from the rosin and the alcoholic hydroxyl group derived from the polyhydric alcohol proceeds. As mentioned above, the polyhydric alcohol is used as an optional component in the esterification step of the present invention, and is not particularly limited in the present invention, and various known ones can be used.

Specific examples thereof include glycerin, trimethylolethane, trimethylolpropane, diethylene glycol, pentaerythritol, and the like.

The resin for printing ink used in the present invention usually has an acid value of 50 or less, preferably 40 or less.

This is because if the acid value exceeds 50, troubles such as scumming tend to occur during printing. The softening point of the resin is usually 140°C or higher, preferably 160°C or higher. This is because if the temperature is lower than 140°C, the setting/drying properties and scumming resistance will be significantly reduced.

The solubility of the resin for printing ink of the present invention consisting of the reaction product obtained in this way is appropriately determined in consideration of workability during printing ink production and printing. The tolerance for is usually 2
It is preferable that it is more than g/g.

In addition, tolerance refers to the amount of solvent used until the dissolved material becomes cloudy when 1 g of resin is dissolved with a solvent.

The reason why the printing ink containing the resin of the present invention has excellent background smudge resistance in dry lithography is due to the fact that the mechanism by which the printing ink peels off from the ink repellent layer, which is mainly made of silicone resin, in dry lithography has not been elucidated. Although it does not go beyond this range, it is based on a new resin. This is thought to be due to the high solvent separation characteristic of rosin-modified phenolic resin.

In other words, one of the explanations for the mechanism by which printing ink peels off from the ink repellent layer in dry lithographic printing is Weak Fluid Boundary, which is related to adhesion failure.
Layer (References: Printed magazine Vol. 60, No. 2, p. 9 onwards: Hereafter.

There is a concept called WFBL.

The concept of WFBL is that the amount of solvent in the ink diffuses onto the surface of the silicone resin that forms the ink repellent layer of dry lithography, forming a boundary liquid film layer, and the image is reproduced by the destruction of this boundary liquid film layer. It is.

It is believed that the above-mentioned characteristics of the dry planographic ink of the present invention facilitate the formation of a boundary liquid film layer based on the -FBL concept, resulting in improved scumming resistance.

The printing ink varnish of the present invention is prepared by reacting rosins and phenols in the presence of an acid catalyst, and then forming a novolak compound.
0% by weight, ink solvent 20-70% by weight, drying oil such as linseed oil, tung oil, rice bran oil, soybean oil, polymerized oils of these, or drying oil alkyd resin, as necessary.
Add 30% by weight and dissolve at 180°C. In actual use, it is desirable to use a known gelling agent such as aluminum octylate, aluminum stearate, zirconium octylate, aluminum triisopropoxide, aluminum diisopropoxide monoacetylacetate, etc. to form a gel varnish. In addition, pigments such as yellow, red, indigo, or ink are dispersed as coloring agents, and compounds such as antifriction improvers, ink dryers, and drying inhibitors are added as necessary.

By adjusting the viscosity to an appropriate level, it becomes sheet-fed type and off-wheel type dry lithographic printing ink.

Furthermore, organopolysiloxane can also be added if necessary. The amount added is desirably 5% by weight or less; adding more than that will deteriorate the gloss. Examples of the organopolysiloxane include methylpolysiloxane, methylphenylpolysiloxane, dimethylpolysiloxane, alkylaryl-modified silicone oil, and the like.

Incidentally, when preparing the ink, an appropriate amount of a known resin for printing ink such as a rosin-modified phenol resin may be used in combination.

Hereinafter, the present invention will be explained in more detail by giving specific examples, but it goes without saying that the present invention is not limited to these. Note that hereinafter, "part" and "%" refer to 9% by weight.

Intermediate Production Example 1 A flask equipped with a stirrer, a Liebig condenser, and a thermometer is charged with gum rosin loosin, 1000 parts of carbolic acid, and 0.7 part of paratoluenesulfonic acid as a catalyst, and the temperature is raised to 150 to 170°C. The reaction was carried out at the same temperature for 5 hours, and while unreacted carbolic acid was distilled off, the
The temperature was raised to 260°C, and about 1200 ml of a rosin-phenol reaction product (hereinafter referred to as intermediate) was obtained. The acid value of the reactant was 107. The softening point was 110°C and the hydroxyl value was 75.

Intermediate Production Example 2 In Intermediate Production Example 1, the amount of 1-carboxylic acid used was reduced to 570 parts, and the reaction time at 150 to 170°C was changed from 10 to
The same operation was performed except that the time was extended to 13 hours, and the acid value was 10.
5. Intermediate with a softening point of 120°C and a hydroxyl value of 70, approximately 1200
I got the department.

Resin Production Example 1 ``Into a flask equipped with a stirrer, Liebig condenser, and thermometer, 1000 parts of the intermediate obtained in Intermediate Production Example 1, 45 parts of paraformaldehyde, and 1.5 parts of paratoluenesulfonic acid.
and 150 parts of xylene.

The temperature was raised to 100-110°C. After carrying out the novolak reaction at the same temperature for 4 hours, 250
The temperature was increased to ~260°C. Further, an esterification reaction was carried out at the same temperature for 8 hours, and 1 the resin for printing ink of the present invention had approximately 95%
I got 0 copies. The acid value of this substance is 25 and the softening point is 177°C.
Met. This resin is referred to as resin A.

Resin Production Example 2 The same operations as in Resin Production Example 1 were performed except that the type of intermediate used was changed to that obtained in Intermediate Production Example 2.

Acid value 22. 950 parts of resin with a softening point of 175°C was obtained.

This resin will be referred to as resin B.

Resin Production Example 3 As in Resin Production Example 1, 1000 parts of the intermediate obtained in Intermediate Production Example 1, 200 parts of paraoctylphenol, 63 parts of paraformaldehyde, and paratoluenesulfone were placed in a flask equipped with a stirrer, a Liebig condenser, and a thermometer. Acid 0.
5 parts and 212 parts of xylene, 100 to 110
Raise the temperature to ℃. After carrying out the novolac formation reaction at the same temperature for 4 hours, the temperature is heated to 250 to 260° C. while distilling off xylene. Further, esterification reaction was carried out at the same temperature for 10 hours to obtain 1137 parts of resin. The acid value of this thing is 23
．． The softening point was 177°C. This resin is referred to as resin C.

Resin Production Example 4 In Resin Production Example 3, the novolak-forming reaction was performed in the same manner, and after heating to 250 to 260°C.

50 parts of glycerin was charged and an esterification reaction was carried out at the same temperature for 8 hours, resulting in an acid value of 21. 1182 parts of a resin having a softening point of 176°C was obtained. The resin is called resin.

Example of producing varnish A fourth flask equipped with a stirrer, condenser, and thermometer was charged with 185 parts of the resin shown in Table 1, 175 parts of the solvent also shown in Table 1, and 40 parts of No. 00 linseed oil polymerized oil, and nitrogen gas was added. The mixture was heated to 180° C. and stirred for 30 minutes to dissolve, thereby obtaining varnishes 1 to 7 of Examples and varnishes 1 to 5 of Comparative Examples.

Gel varnish production example 340 parts of the varnish obtained in the varnish production example was charged into four flasks equipped with a stirrer, condenser, and thermometer.

Stir while blowing nitrogen gas, raise the temperature to 80 ° C, add 30 parts of a gelling agent in which 6 parts of Offtope A1 (gelling agent manufactured by Hope Pharmaceuticals) is dispersed in 24 parts of the solvent shown in Table-1, The temperature was raised to 170° C. and stirred for 30 minutes to obtain a gel varnish. These gel varnishes are referred to as Gel Varnishes 1 to 7 of Examples and Gel Varnishes 1 to 5 of Comparative Examples.

Ink production example 65 parts of gel varnish prepared in the KEL varnish production example.

After dispersing 18 parts of Carmine 6BA (red pigment made by Toyo Ink Manufacturing Co., Ltd.) using three rolls and adding 1 part of a dryer, the total amount was 100 parts using the combination of varnish, gel varnish, and solvent shown in Table 1. The tank value is 9.0-10.
0. Flow value is 19.0-20.0 (at 25℃)
The inks of Examples 1 to 7 and the inks of Comparative Examples 1 to 5 were obtained.

In addition, 2% of Shin-Etsu Silicone KF96 (organopolysiloxane manufactured by Shin-Etsu Silicone Jun) was added and mixed to the inks of Example 1 and Comparative Example 1, and Example IS and Comparative Example I were mixed.
SO ink was obtained.

■Damanol 354 manufactured by Arayo Kagaku Kogyo Rosin modified phenolic resin Softening point 170℃, acid value 18 ■Tamanol 361
Rosin-modified phenolic resin, manufactured by Arayo Kagaku Kogyo Co., Ltd. Soft break point: 155°C, acid value: 20 ■ No. 0 truben) H, manufactured by Nippon Petrochemicals, normal paraffinic solvent, No. 5 solvent, No. 3 solvent, ink solvent manufactured by Nippon Oil Co., Ltd. Evaluation] These inks were printed using a dry lithographic plate, and the background smudge temperature and the gloss of the printed matter were measured. In other words, a dry lithography plate with an ink repellent layer made of silicone rubber is attached to a printing machine that has been modified to increase the temperature of the plate surface by installing an electric heater on the second plate cylinder. Printing was carried out while maintaining the density and increasing the printing surface area, and the temperature at which scumming occurred was measured. The results are shown in Table-2.

In addition, the background smudge resistance is determined from the temperature at which background smudge occurs in dry lithographic printing: less than 27°C is "poor", 27 to 32°C is "medium",
A temperature of 32°C or higher is indicated as "good".

In addition, the gloss has no background stains and the solid density is 1.70 to 1.
About 75 printed materials Murakami Color Glossmeter DM-
26D (60'-60').

Table 2 [Effects of the Invention] As described above, the dry lithographic ink of the present invention is a printing ink that has good scumming resistance and excellent print gloss.

Claims (1)

[Scope of Claims] 1. In a printing ink used in lithographic printing that does not require dampening water, a reaction product obtained by subjecting rosins and phenols to a heating reaction in the presence of an acid catalyst is added to the reaction product as necessary. An alkylphenol containing an alkyl group having 4 to 12 carbon atoms is mixed and reacted with formaldehyde in the presence of an acid catalyst to form a novolak, and then a polyhydric alcohol is added in an amount not exceeding 10% by weight based on the novolak. 1. A dry lithographic printing ink comprising, as a varnish component, a rosin-modified phenolic resin which is a reaction product obtained by esterifying the novolak compound using a varnish. 2. The dry lithographic printing ink according to claim 1, wherein the softening point of the rosin-modified phenolic resin measured by the ring and ball method is 140° C. or higher. 3. The dry lithographic printing ink according to claim 1 or 2, further comprising an organopolysiloxane.