JPS6336638B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a lithographic printing ink composition using dampening water. A lithographic printing plate consists of an oleophilic image area that accepts oil-based ink and an oil-repellent non-image area that does not accept ink, and the non-image area generally consists of a hydrophilic area that accepts water. Therefore, in normal lithographic printing, both ink and water are supplied to the plate surface, the image area selectively receives colored ink and the non-image area selectively receives water, and the ink on the image area is transferred to a substrate such as paper. This is done by being transcribed into . Lithographic printing plates that use dampening water include presensitized plates (so-called PS plates) that use diazonium compounds,
Planographic printing plates based on an electrophotographic method using zinc oxide or an organic photoconductor, and planographic printing plates based on a silver salt photographic method using a silver halide emulsion as a photosensitive component are known. A wide variety of inks are known for use in printing. However, with conventional printing inks, even if good prints can be obtained in the case of a specific printing plate or dampening solution, the type and printing conditions may change. Depending on the situation, various drawbacks may occur, and in some cases, it may not be possible to use it at all. It goes without saying that the properties required of such printing ink are that a sufficient amount of ink adheres to the printed areas and that no ink adheres to non-printed areas. Furthermore, the above properties must be obtained without causing emulsification with dampening water. Further, as mentioned above, it is desirable that the printing method be unaffected even if the plate material, type of dampening solution, printing conditions, etc. change. An object of the present invention is to provide an ink composition for lithographic printing using dampening water that satisfies the above-mentioned requirements. As a result of extensive research to achieve the above object, the present inventors have found that by using an ink composition containing the compounds described below, stains are less likely to occur in non-image areas, and image lines are less likely to be stained. It has been found that it is possible to perform lithographic printing using dampening water by giving sufficient concentration to the parts, making emulsification less likely to occur, and having greater tolerance to changes in conditions. Such a compound is an organopolysiloxane containing at least one of each of two substituents, substituent A and substituent B. Here, substituent A has the formula (In the formula, x is an integer from 0 to 4, a is a number from 1 to 50 on average, b is a number from 0 to 50 on average, R' is a hydrogen atom,
represents an alkyl group or an acyl group), and the substituent B is represented by the formula

[Formula] or

[Mountain water solution prescription]

O-phosphoric acid 10g Nickel nitrate 5g Sodium nitrite 5g Ethylene glycol 100g Colloidal silica (20% liquid) 23ml Add water to make 20 [Ink (A) formulation and manufacturing method] Γ Carbon black for prescription printing ink 200 Phthalocyanine Blue 50 Rosin modified phenolic resin 200 Silicone modified alkyd resin (A ₁ ) 200 Linseed oil 100 High boiling point solvent (No. 0 Solvent H) 200 Wax compound 40 Cobalt naphthenate salt (metal concentration 7.5%) 10 total 1000 parts of the above mixture Ink (A) was obtained by uniformly kneading the mixture using three rolls. Γ Production of silicone-modified alkyd resin (a ₁ ) Phthalic anhydride 100 parts Olefiic acid 50 parts Glycerin 50 parts Exemplary compound (3) 25 parts Isophorone 25 parts Butyl cellosolve 200 parts The above mixture was reacted at 150°C for 2 hours to undergo silicone modification. An alkyd resin (a ₁ ) was obtained. [Formulation and manufacturing method of ink (B)] The following compound in place of exemplified compound (3) in ink (A)
It was produced in exactly the same manner as ink (A) except that (b) was used. compound (b) Example 2 It is possible to produce an ink using disazo yellow carmine 6B and phthalocyanine blue as pigments in the ink (A) of Example 1, and the above-mentioned lithographic printing plate, which is prone to scumming with colored inks, also has these drawbacks. It was confirmed that good printing was possible with no blemishes at all. Example 3 The alkyd resin used in the ink (A) of Example 1 and the exemplified compound (3) were kneaded in advance at room temperature to prepare an ink additive composition, and the silicone-modified alkyd resin (a ₁ ) of the ink (A) was kneaded in advance at room temperature. used instead. The same results as ink (A) were obtained, and it was confirmed that the ink composition of the present invention does not necessarily have to be a heat reactant. Example 4 Example compound (3) used in the production of silicone-modified alkyd resin (a ₁ ) was converted into example compound (1), (2), (4) or
When Example 1 was repeated in exactly the same manner except for replacing ink (5), the same results as ink (A) were obtained.
The method for producing silicone-modified alkyd resins is described in detail in, for example, Japanese Patent Application Laid-open Nos. 50-71410 and 50-71411, which can be referred to. Example 5 When printing was carried out in the same manner as in Example 1 using the following ink, the same results as ink (A) of Example 1 were obtained. Carbon black for printing ink 200 Phthalocyanine blue 50 Rosin-modified phenolic resin varnish ( _A2 ) 400 Wax compound 40 Cobalt naphthenate salt (metal concentration 7.5%) 10 Manganese naphthenate salt (metal concentration 6.5%) 10 No. 0 Solvent H ( Nippon Oil) 290 Γ Above rosin modified phenolic resin varnish (a ₂ )
Prescription of rosin-modified alkylphenol resin 500 Silicone-modified linseed oil (A ₂₁ ) 300 Dehydrated castor oil 200 Γ Manufacturing method of the above-mentioned silicone-modified linseed oil (A ₂₁ ) Linseed oil 700 Exemplary compound (3) 300 Total 1000 parts Mixture consisting of the above composition were reacted at 150°C for 3 hours to obtain the ink composition of the present invention. Other exemplified compounds (1) and (5) in place of exemplified compound (2)
Similar results were obtained when using . The method for producing silicone-modified vegetable oil is described in detail in, for example, Japanese Patent Application Laid-open Nos. 51-21906 and 51-21907, so please refer to these. Example 6 10% by weight of the ink composition of the present invention used in Examples 1 to 5 was added to seven types of commercially available ink compositions with different ink tack values and colors, and the ink was well kneaded and the commercially available ink without additives was mixed. When printing was carried out using these materials, the same results as those obtained in Example 1 were obtained. Example 7 Example 6 was repeated using a commercially available PS plate and a printing plate using zinc oxide, each using their own dampening water. A remarkable difference was observed in all planographic printing plates. Example 8 When printing was carried out using an ink prepared by adding 2% by weight of exemplified compound (1) or (4) to a commercially available ink composition and well-kneaded, and an ink without the additive, the same results as in Example 6 were obtained. It was done.

Claims (1)

[Scope of Claims] 1. A lithographic printing ink composition containing an organopolysiloxane, wherein the organopolysiloxane contained in one molecule contains two types of the following formulas A and B. An ink composition for lithographic printing using dampening water, characterized in that it contains at least one substituent. Formula A; (In the formula, x is an integer from 0 to 4, a is a number from 1 to 50 on average, b is a number from 0 to 50 on average, R' is a hydrogen atom,
Represents an alkyl group or an acyl group. ) Formula B; [Formula] or [Formula] (In the formula, y is an integer of 0 to 4, R'' and R are saturated or unsaturated hydrocarbons having 1 to 30 carbon atoms that do not contain terminal unsaturated bonds, z represents an integer from 2 to 30.) 2. Claims containing the organopolysiloxane in the form of a mixture with or a reactant with a resin or oil that is miscible with the organopolysiloxane. The lithographic printing ink composition according to item 1.