US 4,304,601 A · Planographic printing ink

Abstract

A novel ink formulation, especially useful in Driography printing, is disclosed. The ink formulation comprises a basic planographic printing ink vehicle, a pigment, a modifying varnish and a flow control agent to provide an ink, especially suitable for use in Driography, which exhibits desirable handling-viscosities under ambient conditions, improved rheological properties under severe press-operating conditions, and provides printings having sharp delineation, fidelity and excellent reproducibility in depth of color tones in long press runs. The basic printing ink vehicle may be a vehicle designed for either sheet-fed or heat-set printing systems. The novel ink formulation is designed to have a high viscosity and avoid becoming pseudoplastic in its behavior at higher press temperatures, which generally can range from about 85.degree. F. to 125.degree. F., and preferably, avoids becoming pseudoplastic at temperatures up to about 140.degree. F. or more.

Claims53

Dependent claims

A planographic printing ink which is thermally stable at temperatures of about 85.degree. F. to 140.degree. F. and especially adapted for use in Driography comprising (a) pigment dispersed in a planographic ink vehicle;

(b) a modifying varnish in an amount sufficient to provide an ink having a yield value below about 5000 dynes/cm.sup.2 and a viscosity above 100 poise at 40.degree. C. with high internal cohesion, the modifying varnish being selected from the group consisting of cyclised rubber, dimerized rosin esters, alkyds, rosin modified alkyds, esterified rosin modified oleoresinous gells, and hydrocarbon resin solutions;
and (c) a silicone polymer, flow control additive in an amount sufficient to increase the temperature, at which the ink becomes pseudoplastic, to at least 85.degree. F. and provide an ink having a low surface energy;
said internal cohesion being sufficient to maintain wetting and transference of the ink to the image areas of a printing plate whereas said surface energy is sufficiently low to avoid wetting, by the ink, of the non-image areas of the printing plate within the operating temperatures of the plate.

A planographic printing ink having thermal stability at temperatures between about 85.degree. F. and 140.degree. F. comprising by weight about 25 to 60% of a oil-based, planographic, basic printing ink vehicle, about 10 to 50% pigment, about 3 to 35% of a modifying varnish different from the basic printing ink vehicle and selected from the group consisting of cyclised rubber, dimerized rosin esters, alkyds, rosin modified alkyds, heat set esterified rosin modified phenolic oleoresinous gells and hydrocarbon resin solutions, the amount of modifying varnish being sufficient to provide an ink having a yield value below about 5000 dynes/cm.sup.2 and a viscosity above 100 poise at 40.degree. C. with high internal cohesion, and about 0.25 to 2% (dry basis) of a silicone polymer, flow control additive, the amount of silicone polymer flow control additive being sufficient to increase the temperature, at which the ink becomes pseudoplastic, to at least 85.degree. F. and provide an ink having a low surface energy, said internal cohesion being sufficient to maintain wetting and transference of the ink to the image areas of a printing plate whereas said surface energy is sufficiently low to avoid wetting, by the ink, of the non-image areas of the printing plate within the operating temperatures of the plate.

In a planographic printing ink comprising a planographic printing ink vehicle and pigment, the improvement comprising a process providing a planographic printing ink which is thermally stable at temperatures of 85.degree. F. to 140.degree. F., especially adapted for use in Driography, comprising incorporating into the planographic printing ink (a) a modifying varnish different from the basic printing ink vehicle and selected from the group consisting of cyclised rubber, dimerized rosin esters, alkyds, rosin modified alkyds, heat set esterified rosin modified oleoresinous gells and hydrocarbon resin solutions, said modifying varnish being added in an amount sufficient to provide an ink having a yield value below about 5000 dynes/cm.sup.2 and a viscosity above 100 poise at 40.degree. C. with high internal cohesion, and (b) a silicone resin, flow control additive in an amount sufficient to increase the temperature at which the ink becomes pseudoplastic to at least 85.degree. F. and thereby provide an ink having a low surface energy, said internal cohesion being sufficient to maintain wetting and transference of the ink to the image areas of a printing plate whereas said surface energy is sufficiently low to avoid wetting, by the ink, of the non-image areas of the printing plate within the plate operating range of temperatures.

A planographic printing ink having thermal stability at temperatures between about 85.degree. F. and 140.degree. F. and especially adapted for use in Driography comprising

(a) pigment dispersed in an oil-based, phenolic or maleic resin, planographic printing ink vehicle;
(b) a modifying varnish, which is cyclised rubber, dimerized rosin ester of heat-set, esterified, rosin modified phenolic oleoresinous gel, in an amount sufficient to provide the ink with a yield value below about 5000 dynes/cm.sup.2, a viscosity above 100 poise at 40.degree. C., and high internal cohesion;
(c) a silicone polymer flow control additive which is a silicone-polyether in an amount sufficient to increase the temperature at which the ink becomes pseudoplastic to at least 85.degree. F. and provide an ink having a low surface energy;
said internal cohesion being sufficient to maintain wetting and transference of the ink to the image areas of a printing plate whereas said surface energy is sufficiently low to avoid wetting, by the ink, of the non-image areas of the printing plate within the operating temperatures of the plate;
and
(d) a tack masking organo-silicone oil having a viscosity of about 200 to 600 centistokes in an amount effective to reduce the tack of the ink.

3 more elements

Dependencies are inferred from the claim text.

Planographic printing ink

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Planographic printing ink

Life of this patent

Abstract

Claims53