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US 8,507,181 B2Granted
Method for developing and sealing of lithographic printing plates
OwnerChristopher D. Simpson, Bernd Strehmel +3inventors
InventorsChristopher D. Simpson, Bernd Strehmel, Harald Baumann, Ulrich Fiebag, Mathias Jarek
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Abstract
A method is described for producing an imaged lithographic printing plate, wherein the developer comprises a hydrophilic polymer comprising (m1) structural units derived from at least one compound comprising both a polyalkylene oxide chain and a free radical polymerizable group, and (m2) structural units derived from at least one compound copolymerizable with the free radical polymerizable group of (i) and comprising at least one functional group with pKs<5.
Claims17
Method of producing an imaged lithographic printing plate comprising:
- (a) imagewise exposing a lithographic printing plate precursor comprising
- (i) a substrate,
- (ii) a radiation-sensitive coating comprising one or more layers, and
- (iii) optionally an oxygen-impermeable overcoat, to radiation for which the radiation-sensitive coating is sensitive;
- (b) treating the imagewise exposed precursor with an aqueous developer to remove non-image areas of the radiation-sensitive coating and to provide a protective gumming in a single step, the aqueous developer having a pH value of >6 and comprising
- (i) water,
- (ii) at least one hydrophilic polymer, comprising:
- (m1) structural units derived from at least one compound comprising both a polyalkylene oxide chain and a free radical polymerizable group, which (m1) structural units are present in the hydrophilic polymer in an amount of from 5 weight % to 95 weight %, and
- (m2) structural units derived from at least one compound copolymerizable with the free radical polymerizable group of (m1) and comprising at least one acidic group with pKs<5, wherein the acidic functional group(s) can be present as free acid group(s) or in salt form, which (m2) structural units are present in the hydrophilic polymer in an amount of from 5 weight % to 95 weight %,
- (iii) optionally at least one member selected from surfactants, alkaline reagents, water-soluble film forming hydrophilic polymers, additives selected from organic solvents, biocides, complexing agents, buffer substances, filter dyes, antifoaming agents, anticorrosive agents and radical inhibitors;
- and
- (c) optionally at least one step selected from rinsing with water, drying, and baking,
- wherein the hydrophilic polymer (ii) further comprises structural units (m3) derived from at least one kind of monomer that contains at least one free radical polymerizable group but that does neither contain an acidic group with pKs<5 nor a polyalkylene oxide chain.
10 more elements
Dependencies are inferred from the claim text.