Water-developable photosensitive plates especially suited for commercial flexographic printing

A water-developable photosensitive resin composition having a thickness increase, after photopolymerization and development thereof, upon immersion in water for 24 hours at ambient conditions, of less than about 3%, and hardness, as measured by the Shore A test, of less than about 75, said composition comprising:

• (A) in the range of about 30 up to 90 wt % of a copolymer comprising in the range of:
• (i) 5 up to 95 mol % of an aliphatic conjugated diene monomer,
• (ii) 1 up to 30 mol % of an .alpha.,.beta.-ethylenically unsaturated carboxylic acid,
• (iii) 0.1 up to 10 mol % of a polyfunctional vinyl monomer, and
• (iv) 0 up to 70 mol % of a monofunctional vinyl monomer;
• (B) in the range of about 0.2 up to 2 mol of a basic nitrogen-containing compound per mol of carboxyl groups in copolymer (A),
• (C) in the range of about 5 up to 70 wt % of a mixture of ethylenically unsaturated monomers, wherein said mixture contains at least one ethylenically unsaturated monomer selected from each of (a), (b), (c) and (d) below, wherein each of (a), (b), (c) and (d) have the core structure:
• ##STR5## wherein R is H or methyl, and X is selected from:
• (a) an alkyl group having in the range of about 8 up to 15 carbon atoms,
• (b) ##STR6## wherein each R' is independently selected from H or methyl, R is as defined above, selected independently of R of the core structure, and x is an integer falling in the range of about 2 up to 6,
• (c)
• --[(CH.sub.2).sub.x' --O].sub.y --Y
• wherein x' is an integer falling in the range of about 1 up to 12, y is an integer falling in the range of about 4 up to 12, and Y is selected from:
• alkyl having in the range of about 3 up to 15 carbon atoms such that two or more of the core species can be linked to one another, or ##STR7## wherein R is as defined above and is selected independently of R of the core structure, and
• (d) ##STR8## wherein x' and Y are as defined above, Z is an aliphatic, aromatic, aliphatic-substituted aromatic, or aromatic-substituted aliphatic linker having a molecular weight in the range of about 4,000-5,000, and z is an integer which falls in the range of about 0 up to 10, and
• (D) in the range of about 0.01 up to 10 wt % of at least one photopolymerization initiator.