Gencorp, Inc.

Andrew L Ratermann

Earl G Melby

Douglas S McBain

Kevin P LaJudice

I Glen Hargis

This invention relates to a thermosetting unsaturated polyester or vinyl ester resin compositions modified with AB or ABA block copolymers. The A blocks are unsaturated polyester while the B blocks are flexible poller having a Tg of 0.degree. C. or lower. The blocks are generally separately prepared having a variety of terminal groups such as hydroxyl, carboxyl, amine, or isocyanate groups, but low molecular weight A blocks can be prepared in situ on the B blocks, The functionality of the blocks can be controlled to get AB or ABA diblocks and polyblocks, These modified unsaturated polyester or vinyl ester resin compositions have higher flexural strain to failure and are generally tougher than standard resins without modification. Control of the reaction conditions and the functionality of the blocks prior to coupling minimizes the formation of A(BA).sub.n where n is an integer above 1.

Unsaturated polyester-modified flexible polymers for use in molding

A block copolymer of generally an AB, ABA, or A(BA).sub.n structure, or mixtures thereof where the A block is an unsaturated polyester, the B block is a flexible polymer having a Tg of 0.degree. C. or lower, and n is 2 to 5. The various block components are generally first separately prepared as polymers with the flexible polymer generally having 1 or 2 functional end groups such as an amine group, a carboxyl group, or a hydroxyl group with the later being preferred. Alternatively, for low molecular weight unsaturated polyester blocks, the block can be made in situ. The preferred reaction route is to react a mono or dihydroxy terminated flexible polymer with a diisocyanate which subsequently can be readily reacted with the polyester. The block copolymers can be utilized as toughening agents. They furthermore can be utilized to coat a fiber structure such as individual fibers, a woven structure, or a nonwoven structure such as mats, rovings, bundles, and the like, with the coated fiber structures subsequently incorporated into a polymeric matrix such as polyester.

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Indianapolis, IN, United States of America

Andrew L Ratermann