FI77685C - Desensitizing ink for wet offset printing. - Google Patents

Description

77685

Deenable ink for wet of fset printing

The invention relates to a de-inking ink for wet offset printing on a receiving surface of a chemical self-copying assembly comprising at least two superimposed sheets, one of which has a receiving electrophilic coating and the other a nucleophilic coating capable of causing a chromogenic reaction with said recipient. .

GB Patent No. 1,433,469 already discloses desensitizing inks containing polypropylene glycol having a molecular weight of 400 to 5,000, which can be printed, flexographic or heliographically printed on the receiving surface of the self-copying assembly and thus prevent any color formation in this way. printed areas when something is later written or touched on the carbonless paper.

However, as mentioned in GB Patent No. 1,525,269, the holder of GB Patent No. 1,433,469 had not succeeded in developing a polyalkylene glycol-based ink capable of performing wet offset printing on the receiving surface of a chemical self-copying assembly.

As described in CH Patent No. 628,288, the assignee of the present invention has developed a desensitizing ink based on polyalkylene glycol or other high molecular weight nucleophilic alkoxy compounds which can be pressed by wet offset printing to the receiving surface The lipophilic equilibrium is 2 to 9 in order, on the one hand, to continuously transfer the ink of the color rolls to the hydrophobic areas of the wetted 2,776,85 printing plate of the offset printing machine and, on the other hand, to neutralize the corresponding areas of the chemical self-copying assembly receiving surface.

In order to increase the molecular weight of the desensitizing compound on the ink of the invention, it is characterized in that the nucleophilic alkoxy compound is crosslinked with an aliphatic or aromatic polyisocyanate derivative, which can further improve the ink transfer to the wet offset printing machine color path. The result is still that the ink feed of the color path rollers remains the same thickness. Such an ink film is particularly resistant to shocks because the wetting water is emulsified in the ink before it is transferred first to the offset printing plate, then to the rubber roll and finally to the desensit1 large Ivana ink layer, 1.5-5 g / m 2, on the paper base.

The essential features of the invention are set out in the appended claims.

The composition of the desensitizing ink according to the invention for wet offset printing on the receiving surface of a chemical copying unit can be determined as follows.

Example 1

In a three-cylinder grinder, 70 parts of a lacquer obtained by reacting 63 parts of polypropylene glycol (Molecular weight 2550) with 5 parts of hexamethylene triisoheoate and adding 32 parts of acid-modified phenolic resin, 13 parts of titanium dioxide and 1 part of silicon oxide are mixed.

To this ink powder is added 12 parts of an alkoxy compound. The HLB value of the ink rises to 3 (± 1). The theological properties of this ink are suitable for wet of fset printing.

Example 2

In a three-cylinder grinder, 68 parts of a lacquer obtained by reacting 66 parts of propoxyldiethylenetriamine (molecular weight 2500) with 9 parts of isocyanotri

II

3,776,85 methylolpropane treated with 3 parts of tolylene diisocyanate and the addition of 25 parts of acid-modified phenolic resin, 12 parts of titanium dioxide, 2 parts of silica and 6 parts of calcium carbonate.

To this ink powder is added 12 parts of an alkoxy derivative. The HLB value of the ink rises to 4 <+. 1). The theological properties of this ink are suitable for wet offset printing.

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In a three-cylinder grinder, 60 parts of a lacquer obtained by reacting 5 Θ parts of polypropylene glycol (Molecular weight 2500) with Θ parts of ricinoleic acid and 10 parts of isocyanotrimethylolpropane treated with 3 moles of titanium diisocyanate, , 2 parts of silica and 6 parts of calcium carbonate.

To this ink powder is added 12 parts of an alkoxy derivative. The HLB value of the ink rises to 3 (+.1). The theological properties of this ink are suitable for wet offset printing.

Example 4

In a three-cylinder grinder, 60 parts of a varnish obtained by reacting 72 parts of propoxyldiethylenetriamine (molecular weight 2500) with 5 parts of castor oil and 5 parts of hexamethylene triisocyanate and adding 18 parts of neutral esterified rosin oxide and 6 parts of titanium dioxide to 20 parts of titanium are mixed. calcium carbonate.

To this ink powder is added 12 parts of an alkoxy derivative.

The HLB value of the ink rises to 4 (± 1). The theological properties of this ink are eopvat for wet of fset printing.

4,77685

Example 5

In a three-cylinder grinder, 6Θ parts of a lacquer obtained by reacting 75 parts of polypropylene glycol (Molecular weight 2500) with 5 parts of a long-chain oil oil alkyd and 5 parts of a hexamethylene triisocyanate and adding 15 parts of an acid-modified phenolic titanium resin 2, 6 parts of potassium carbonate.

To this ink powder is added 12 parts of an alkoxy derivative. The HLB value of the ink rises to 3 (+.1). The theological properties of this ink are suitable for wet offset printing.

In the desensitizing ink defined in Examples 3, 4 and 5, either a hydroxyl-containing fatty acid (Example 3) or a fatty oil (Example 4) or a long-chain petroleum alkyd (Example 5) was replaced with a portion of the nucleophilic alkoxy compound to give the ink viscosity.

To facilitate testing of the hydrophilic areas of the printing plates in wet offset printing, some or all of the water required to moisten these areas can be emulsified in its ink.

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Claims (9)

1. A hydrogen sulfide printing ink on the receiving surface of a chemically non-copying unit comprising a nucleophilic alkoxy compound, characterized in that the nucleophilic alkoxy compound is crosslinked in the form of polyurethane, thereby increasing its molecular weight to increase its bleach weight. Black according to claim 1, characterized in that the nucleophilic alkoxy compound is cross-linked in the form of polyurethane with an aliphatic or aromatic polyieocyanate compound. Ink according to claim 1, characterized in that it contains water emulsified in the ink medium. 4. Ink according to claim 1 or 3, characterized in that the amount of water emulsified in the ink medium is sufficient to partially moisten the printing plate hydrophilic areas at the hydrogen pressure. Ink according to Claim 1 or 3, characterized in that the amount of water emulsified in the ink medium is sufficient to guarantee optimum wetting of the printing plate hydrophilic areas at the hydrogen discharge pressure. 6. Ink according to claim 1 or 2, characterized in that a portion of the nucleophilic alkoxy compound has a fatty acid containing the mine an OH group, wherein the nucleophilic alkoxy compound and the fatty acid are crosslinked in the form of polyurethane with an aliphatic or aliphatic poly. ieocyanatderivat. Ink according to claim 1 or 2, characterized in that a portion of the nucleophilic alkoxy compound eubetituerae with a fatty oil containing the mine contains an OH group, wherein