Patents

PATENT NUMBER 4,597,793  
Desensitizing ink for wet offset printing

Abstract

In a desensitizing ink for the wet offset printing of a given area of the acceptor surface of a duplicating set containing an alkoxylated nucleophilic compound, preferably having a molecular weight lying in the range of from 2000 to 4000 and having a hydrophilic-lipophilic balance (HLB) of from 3 to 6, emulsified water is added to the mass of ink. This rapidly forms a fine stable emulsion of water in the ink which is favorable for continuous wet offset printing.

 

Current U.S. Class:	106/31.14; 106/31.24; 106/31.26; 427/150; 427/151; 427/152; 428/207; 428/411.1; 428/914; 503/200
Intern'l Class:	C09D 011/00
Field of Search:	106/21,23,20 282/27.5 427/150,151,152 428/207,914,411 346/200

Chemicals Referenced

"alkoxylated nucleophilic compound; water/ink balance (HLB) value of from 0 to 8; or 3 to 6; or 700 to 10,000; or 2,000 to 4,000; polypropoxylated organic derivative; nucleophilic compound is an adduct of a primary or secondary amine, an alkylene or polyalkylene polyamine or a polyimine with propylene oxide or a mixture of alkylene oxides; (2(2'-hydroxy-3',5'-di-ter-butylphenyl)-benzotriazole in a proportion of from 1 to 10 parts of the total amount of ink; alkoxylated nucleophilic derivative represents from 10 to 60% of the desensitizing ink; hydrated, dimerised or polymerised colophane, colophane esterified with monoalcohols or polyalcohols, with resin forming agents such as acrylic acid and butynediol or maleic acid and pentaerythritol, modified colophane resin, the calcium or zinc salts of colophane, abietic acid and its esters, resins based on acrylic compounds;Maleic resins, oil-free alkyd resins, styrolised alkyd resins, alkyd resins modified with vinyl toluene, alkyd resins from synthetic fatty acids, alkyd resins from linseed oil, alkyl resins from soya oil, alkyd resins from coconut oil, alkyd resins from tall oil and table oil and acrylic alkyd resins; Terpenic resins; Phenolic resins; in particular phenolaldehyde resins, or polymers and organic acids, in particular aromatic carboxylic acids or polymeric organic acids; (CB) contains a nucleophilic compound; compounds of triaryl methane, diphenylamine, derivatives of xanthene, thiazine, spiropyrane or similar compounds are used as chromogens; 1 to 10% by weight, preferably from 1 to 3%; 40 parts of an acid phenolic resin are dissolved hot in 60 parts of polypropylene glycol (molecular weight 4000); 30 parts of an acid phenolic resin are dissolved hot in 70 parts of propoxylated diethylene triamine (molecular weight 4000); 30 parts of an acid phenolic resin are dissolved hot in 70 parts of propoxylated triethylene tetramine (molecular weight 4000); 45 parts of a neutral esterified colophane resin are dissolved hot in 55 parts of polypropylene glycol (molecular weight 2500); 30 parts of an acid phenolic resin are dissolved hot in 60 parts of polypropylene glycol (molecular weight 4000), and then 10 parts of the benzotriazole derivative are added hot." "This process requires much less pressure to transfer the ink onto the front of a sheet which has microcapsules on the back (CFB). Thus, the risk of bursting the microcapsules is considerably diminished."