Desensitizing solution for lithographic printing plates
AssigneeHoechst Celanese Corporation
InventorsShane Hsieh, Wayne A. Mitchell
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Abstract
The invention provides an organic solvent free, phosphate free, lithographic desensitizing composition which comprises: (a) from about 0.1% to about 20.0% by weight of the composition of a copolymer of polymethyl vinyl ether and maleic acid having the formula ##STR1## which has a molecular weight in an amount of from about 20,000 to about 70,000; and (b) from about 0.1% to about 20.0% by weight of the composition of a desensitizing component comprising one or more hydroxy carboxylic acids or salts; and (c) sufficient water to formulate a desensitizing composition; and (d) sufficient base to adjust the pH of the composition into the range of from about 6.5 to about 7.5.
Claims10
A method for treating an imagewise exposed lithographic printing plate containing a light sensitive diazo compound which comprises removing the non-image portions of said plate and then contacting said plate with an organic solvent free, phosphate free, lithographic desensitizing composition which comprises:
- (a) from about 0.1% to about 20.0% by weight of the composition of a copolymer of polymethyl vinyl ether and maleic acid having the formula ##STR5## which has a molecular weight in an amount of from about 20,000 to about 70,000;
- and
- (b) from about 0.1% to about 20.0% by weight of the composition of a desensitizing component comprising one or more hydroxy carboxylic acids or salts;
- and
- (c) sufficient water to formulate a desensitizing composition;
- and
- (d) sufficient base to adjust the pH of the composition into the range of from about 6.5 to about 7.5.
Dependencies are inferred from the claim text.