JPS58152073A - Ink composition for dry offset printing - Google Patents

Abstract

PURPOSE:To provide an ink composition for dry offset printing, having excellent antigreasing property and fludidity, and good for practical printing, by using a urethane-modified resin and an organic titanate as essential components. CONSTITUTION:The objective ink composition is prepared by adding 0.5-50wt% (based on whole resin component) of a urethane-modified resin and 0.1-10wt% (based on the resin) of an organic titanate compound as a gelling agent e.g. tetraisopropyl(bisdioctylphosphite) titanate to the resin component, gelatinizing the mixture by stirring for 5-30min at room temperature -250 deg.C, and adding a colorant, wax, grease, drying agent, dispersant, etc. to the gelatinzied product. The urethane-modified resin used as a starting material can be obtained by the urethane-forming reaction of a hydroxyl-containing compound (e.g. phenolic resin) with an isocyanate compound.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ink composition for dry lithographic printing that has excellent background stain resistance and fluidity.

In lithographic printing, which is the mainstream of current printing.

Taking advantage of the property that water and oil-based ink repel each other, a printing plate consisting of a hydrophilic non-printing area and a lipophilic printing area is used, water is attached to the hydrophilic non-printing area, and the other side is lipophilic. After applying oil-based ink to the printed area.

Printing is performed by transferring the oil-based ink adhering to the image area to the printing material to obtain the desired printed material.

However, in such a lithographic printing method.

1. It is difficult to control the dampening water, which serves to prevent ink from adhering to non-print areas. Furthermore, the use of dampening water is one of the major technical obstacles in terms of printability and printing effects. Therefore, various attempts have been made to perform dry lithographic printing using lithographic printing plates that do not require such dampening water. As the newest and most practical method of dry lithography,
There is a method of printing using a lithographic printing plate with a non-stick thin film of silicone rubber etc. on the non-image area, and in this case, ordinary oil-based ink is used without supplying dampening water to the second plate surface. It is reported that it can be printed.

However, in practice, it has been found that printing using conventional oil-based inks is undesirable because of its inadequate printability, resulting in scumming.

The phenomenon of scumming in dry lithographic printing occurs because the temperature of the plate surface rises due to friction between the drive unit and rollers of the printing press during printing, and the cohesive force of the ink itself decreases9.
Ink adheres to non-image areas that should originally be ink repellent.

Therefore, one possible way to improve these problems is to use high molecular weight resin to increase the cohesive force.
This method causes problems such as piles on the blanket and paper flakes.

Another improvement method is to add an aluminum compound such as aluminum stearate or aluminum octoate to the festival.

There is a way to make it gel. However, if this method is used to achieve high smudge resistance, the viscosity of the ink will increase significantly, and the transferability of the ink (1), such as transfer on the printing press (1) or transfer to the blanket, will be extremely poor. There is still a problem with this, and the current situation has not reached a stage where I am completely satisfied.

As a result of intensive studies on ink compositions suitable for the above-mentioned dry lithographic printing method, the present inventors found that an ink composition containing a urethane-modified resin and gelled using an organic titanate gave good results. We have arrived at the present invention as described below.

That is, 9 the present invention comprises a urethane modified resin and the following general formula [1
] or [■] The present invention relates to an ink composition for dry lithographic printing characterized by containing at least one organic titanate represented by [ ] or [■].

However, in formula 2, R1: difurkyl group, allyl group, aral #7141 fulkenyl group, alkanoyl group R2: alkylene group, arylene group l is 1 or 2 m, n is an integer of 0 and 4, and m + n = 4 It is.

However, in formula 2, RS is an alkyl group, an allyl group, an aralkyl group, an alkenyl group, an alkanoyl group HA, an alkyl group, an allyl group.

The urethane-modified resin used in the present invention means one produced by a urethane-forming reaction between a hydroxyl group-containing compound and an incyanate compound, such as those listed in (1) to (4) below.

(1) Vegetable oil derivatives having hydroxyl groups, such as vegetable oil (
Partially saponified products of linseed oil, tung oil, safflower oil, etc.)
Vegetable oil (as mentioned above) and polyhydric alcohol (pentaerythritolnato) tonoalcohol rinse reaction product (2) Alkyd resin with hydroxyl group Obtained by condensation reaction of polybasic acid and polyhydric alcohol and has hydroxyl group It is something. These include those modified with modifiers such as fats and oils, oil fatty acids, natural resins (rosin, etc.), and synthetic resins (fe/-/l/resin, melameta resin, urea resin, etc.).

(3) Phenol resin (4) Any of the known mono-, di-, and tri-isocyanate compounds can be used as the rosin-modified phenol m-fat isocyanate compound.

The amount of urethane modified resin used is 0.5 to 50% of the total resin components.
% by weight, preferably from 1 to 40% by weight.

For example, if the amount of the urethane-modified resin used is outside the above range, the performance as an ink will not be balanced.

Other resin components include drying oil and rosin.

Rosin ester, phenolic resin, rosin modified phenolic resin, alkyd resin, epoxy resin.

Amino alkyd resin 2 Petroleum resin, acrylic resin, etc. are used.

Examples of the organic titanate compound represented by the general formula (1) or (II) used as a gelling agent in the present invention include tetraisopropyl (bisdioctyl phosphite) titanate and tris (dioctyl pyrophosphate) ethylene titanate. , impropyl triisostearoyl titanate, impropyl tridodecylbenzenesulfonyl titanate, tetrabutyl titanate, and the like.

The above organic titanate is not only used alone but also in 2fl! The above mixtures are also effective, and can also be used effectively in combination with conventionally used aluminum compounds. In addition, the proportion added to the ink composition is determined by the constituent components of the ink used, but relative to the resin weight,
0.1-10% by weight.

Preferably 0. ．． It is 5 to 5% by weight.

For example, if more than this is used, the fluidity of the ink may deteriorate. However, if the amount is less than this, it is difficult to achieve the object of the present invention.

When the organic titanate is used for a gelation reaction, the reaction temperature is room temperature to 250°C, and the gelation reaction is achieved by adding a predetermined amount to the container and stirring. A reaction time of 5 to 60 minutes is sufficient.

The ink made from fen, which contains urethane-modified resin and uses organic titanate as a gelling agent, has excellent fluidity and excellent soil stain resistance.

Ink using only urethane modified resin and ink using only organic titanate are also excellent.

It has sufficient performance as an ink that can withstand practical printing.

Other components of the ink include (1) colorants used in conventional ink compositions such as inorganic or organic pigments, and (2) waxes, greases, desiccants, dispersants, fillers, etc. Any known one can be used.

Hereinafter, the present invention will be specifically explained with reference to Examples.

Note that the parts used in the 9 examples are based on parts by weight.

Example 1. Comparative Example 1 A product prepared by reacting linseed oil, pentaerythritol and Ink A made from phene gelled by adding dioctyl phosphite) titanate, and Ink B made from phen gelled with aluminum octoate without using a urethane-modified linseed oil derivative, and a urethane-modified linseed oil derivative. The temperature at which scumming occurs, which is a measure of scumming resistance, was measured when ink C gelled with aluminum octoate was prepared.

Both inks A and C were tested at 40°C, and ink B at 37°C, and shea inks A and C had excellent stain resistance.

Furthermore, the fluidity of these inks was measured using a spread meter, and the results were as follows.

Flow value IC (60℃, an) (mm) Ink A 38.3 24.1 Ink B
34.3 21.2 Ink C33,220
, 5 Ink A made from phene impregnated with a urethane-modified linseed oil derivative and gelled with tetraisopropyl bis(dioctyl phosphite) titanate had the best fluidity and had an excellent feel when handled with an ink spatula.

Each of these inks was printed on a Komori Sprint lithographic printing machine using a dry lithographic printing plate having a non-adhesive layer made of silicone rubber without supplying dampening water to the plate surface. the result.

Compared to Ink B and Ink C, Ink A has superior transferability and printing color stability, and is capable of forming halftone dots on printed matter.

It was also found that the paint has excellent solid areas, gloss, and gloss.

[ 1) 47.0 parts Carnauba wax 2.0 parts Paste dryer 1.0 parts Total 100
．． 0 parts When the above mixture was kneaded using a three-roll mill, the incometer tack was 9.7 (400 r, p, m).

A dry lithographic ink having a value of 1 minute at 30° C.) was obtained.

Prescription of rosin-modified phenolic resin varnish (1) Rosin-modified phenolic resin 63.0 parts Polymerized linseed oil 63.0 parts No. 15 Solvent' 54.0 parts (petroleum-based solvent manufactured by Nippon Oil Co., Ltd.) Total 100.0 parts Formula for gel varnish (n) Rosin-modified phenolic resin 62/D part Polymerized linseed oil 4 oil 16.0 parts Urethane-modified linseed oil derivative 12.0 parts No. 5 Solvent 1 690 parts (Nippon Oil Co., Ltd.)
Tetraisoprobyl (dioctyl phosphite) titanate 1.0 parts total 10
0.0 parts Ink B Ink using a aluminum compound as a gelling agent Carbon black 20.0 parts Alkaline blue toner 60 parts Gel varnish (I
I) 47.0 parts carnauba wax 2.0 parts paste dryer
1.0 parts “No. 5 Solvent 1”
4.0 parts (petroleum-based solvent manufactured by Nippon Oil Co., Ltd.) Total 100.0 parts Formula for gel varnish (III) Rosin-modified phenolic resin 32.0 parts Polymerized linseed oil 28.0 parts L'No. 5 Solvent'' 690 parts (Nippon Oil (
Petroleum-based solvent manufactured by Co., Ltd.) Aluminum octoate 1.0 parts total
When 1,000 parts of the above mixture was kneaded using a three-roll mill, an ink with an incometer tack of 11.8 was obtained.

Ink C: An ink containing a urethane-modified linseed oil derivative and using an aluminum compound as a gelling agent and binder Carbon black 20.0 parts Alkaline blue toner 6.0 parts Rosin-modified phenolic resin face (t) 20.0 parts Gel varnish (IV) 47.0 parts Carnauba wax 2.0 parts Paste dryer I, o parts No. 5 solvent 14.0 parts (petroleum-based solvent manufactured by Nippon Oil Co., Ltd.) Total ioo, o parts When kneaded using this roll, an ink with an incometer tack of 10.8 was obtained.

Formula for gel varnish (IV) Rosin-modified phenolic resin 52.0 parts Polymerized linseed oil 16.0 parts Urethane-modified linseed oil derivative 12.0 parts @No. 5 solvent 390 parts (petroleum-based solvent manufactured by Nippon Oil Co., Ltd.) Aluminum octane Eight 1.0 copies total
100.0 parts Evaluation method for background stain resistance (measuring the temperature at which background stains occur) A printing machine modified to raise the temperature of the plate surface by passing hot water into the plate cylinder,
A dry lithographic printing plate having a non-adhesive layer made of silicone rubber was attached, and printing was carried out while raising the temperature of one plate surface without supplying dampening water.

The plate surface temperature at which scumming occurs on a printed matter at a certain density is defined as the scumming temperature. Ink with a high background smudge generation temperature was less likely to cause background smudge, even in practical printing.

Example 2. Comparative Example 2 Ink D using a varnish that uses a urethane-modified alkyd resin and gelled with tris(dioctylpyrophosphate) ethylene titanate with the following composition and a varnish that does not contain a urethane-modified resin and gels with aluminum distearate. I made ink E using. Temperature at which scumming occurs, tack.

When examining the fluidity, Ink D was found to be stain resistant.

It was found that both fluidity was excellent.

Ink D, 42 11.6 54.6 22
．． 4 ink K 59 12.0 31.0 1
9.4 Each of these inks was printed on a Komori Sprint lithographic printing machine using a dry lithographic printing plate having a non-adhesive layer of silicone rubber without supplying dampening water to the plate surface. As a result, ink D becomes ink E.
Excellent metastasis compared to .

It was also found that the gloss of the printed matter was excellent.

Ink D Carmine 6B 20.0 parts Gel varnish (V) SO 19 parts Paste dryer 0.1 part "No. 5 Trubent" 4.0 parts (petroleum-based solvent manufactured by Nippon Oil Co., Ltd.) Total 100゜0 parts Above The mixture was kneaded into ink using a three-roll mill.

Formula for gel varnish (V) Rosin-modified alkylphenol resin 36.0 parts Polymerized linseed oil 10.0 parts Urethane-modified alkyd resin 21.8 parts No. 15 Solvent - 54.0 parts (petroleum-based solvent manufactured by Nippon Oil Co., Ltd.) Tris (Dioctyl pyrophosphate) ethylene titanate 1.2 parts total 100
．． 0 parts Ink E Carmine 6B 20.0 parts Gel varnish (VI) 50.9 parts Paste dryer 0.1 parts "No. 5 Solvent" 4.0 parts (Nippon Oil Co., Ltd.)
Total 100.0 parts Gel varnish (Vl) formulation Rosin-modified alkylphenol resin 35.0 parts Polymerized linseed oil 10.0 parts Long oil linseed oil alkyd resin 22.0 parts No. 5 Solvent 34 .0 parts (Nippon Oil (
(petroleum-based solvent manufactured by Co., Ltd.) Aluminum distearate 1.0 parts total
100.0 copies

Claims (1)

[Claims] (1) An ink composition for dry lithographic printing characterized by containing a urethane-modified resin and at least one organic titanate represented by the following general formula [1] or [1]. However, in formula 2, R+, alkyl group, allyl group, aralkyl group, alkenyl group, alkanoyl group R2: alkylene group, arylene group l is 1 or 2 m, n is an integer from 0 to 4, and m + n = 4. be. However, in formula 9, R5 is a nialkyl group, an allyl group, an aralkyl group, an alkenyl group, an alkanoyl group R4, an alkyl group, an allyl group.