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Abstract

The present invention relates to a high clarity water-sensitive carboxylated nitrile rubber composition which is particularly useful in making photopolymer formulations for printing plates utilized in flexographic printing applications. The present invention more specifically discloses a high clarity water-sensitive carboxylated nitrile rubber composition which is comprised of (a) a carboxylated nitrile rubber which is comprised of repeat units which are derived from about 33 weight percent to about 77 weight percent 1,3-butadiene, from about 15 weight percent to about 45 weight percent acrylonitrile and from about 8 weight percent to about 22 weight percent methacrylic acid and (b) from about 1 to about 10 phr of at least one organic acid which contains at least three carboxyl groups. The carboxylated nitrile rubber of this invention will typically have a Mooney ML-4 viscosity of less than about 80 and a volume swell of greater than 40 percent. It will also have sufficient clarity to allow print having 6-point font to be read through a 0.125-inch thick sheet of said carboxylated nitrile rubber. In applications where improved scorch safety is required, the rubber composition will also contain from about 0.1 phr to about 7 phr of at least one oligomerized fatty acid.

First Claim