Pigment preparation for offset printing with improved rheological properties

摘要

Organic pigment preparation containing a phenolic-modified natural resin which is obtained by reacting a mixture of natural resin or resin acid, mono- or poly-nuclear phenol, aldehyde or aldehyde acetal, Group Ia or IIa metal compound and alpha , beta -unsaturated carboxylic acid or anhydride. Pigment preparations containing an organic pigment and a phenolic-modified natural resin derivative with a weight-average mol. wt. (Mw) of 400-10,000, which is obtained by reacting a mixture of: (a) 50-95 wt. % natural resin or resin acid; (b) 0.5-30 wt. % mono- or poly-nuclear phenols; (c) 0.01-15 wt. % aldehyde or aldehyde acetal; (d) 0.001-2 wt. % Group Ia and/or IIa metal compound(s); and (e) 4.489-30 wt. % alpha , beta -unsaturated carboxylic acid or anhydride with an acid number of 160-300 mg KOH/g. Independent claims are also included for: (i) a process for the production of these pigment preparations by adding the phenolic-modified resin derivative during production of the organic pigment, or to the finely divided powder, or to a press cake or to an aqueous or organic suspension of the pigment; (ii) offset printing ink consisting essentially of a pigment preparation as described and a conventional offset ink varnish.