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US 5,341,799 AGranted
Urethane polymers for printing plate compositions
AssigneeHercules Incorporated
InventorsCharles C. Fifield, Rudolph L. Pohl, Wako Yokoyama
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AssigneeHercules Incorporated
InventorsCharles C. Fifield, Rudolph L. Pohl, Wako Yokoyama
Estimating the term…
A urethane polymer having free acidic groups on the backbone of the polymer and terminal (meth)acrylate groups is prepared by (1) reacting a mixture comprising an aliphatic diol and a diol having acidic functionality with an excess of an aliphatic, cycloaliphatic or aromatic diisocyanate in the presence of a catalyst to produce an isocyanate-terminated urethane polymer and (2) reacting the terminal isocyanate groups of the product of step (1) with a mono- or dihydroxy (meth)acrylate. The diol comprises greater than 50% of the reaction mixture, based on the total weight of reactants. The polymer can be used in photopolymerizable compositions for making low tack flexographic printing plates and photopolymer masters.
A urethane polymer comprising the reaction product of (a) an isocyanate-terminated urethane polymer that is the reaction product of a mixture comprising an aliphatic diol, a diol having acidic functionality and an excess of an aliphatic, cycloaliphatic or aromatic diisocyanate and (b) a mono- or dihydroxy (meth)acrylate, said aliphatic diol comprising greater than 50% of the reaction mixture, based on the total weight of reactants, and said polymer having free acidic groups only on the polymer backbone and (meth)acrylate residues only at the terminals of the polymer.
A process for preparing a urethane polymer having free carboxyl groups on the polymer backbone and terminal (meth)acrylate groups comprising (1) reacting a mixture comprising an aliphatic diol, a diol having acidic functionality and an excess of an aliphatic, cycloaliphatic or aromatic diisocyanate in the presence of a catalyst to produce an isocyanate-terminated urethane polymer having free acidic groups on the polymer backbone and (2) reacting the terminal isocyanate groups of the product of step (1) with a mono- or dihydroxy (meth)acrylate, said aliphatic diol comprising greater than 50% of the reaction mixture, based on the total weight of reactants.
Dependencies are inferred from the claim text.