The Dow Chemical Company

The Upjohn Co.

Steven J Grossman

Kemal B Onder

Shenghong A Dai

Novel polyamide block copolymers are provided which comprise a central block of a soft segment derived from the residue of a polymeric polyol or polyamine joined to terminal hard segment polyamide blocks. The linkages which join the blocks are of a novel type and are the opened form of certain bis azetidine-2,4-dione rings. The block copolymers can be prepared very rapidly via anionically polymerizing lactams on to prepolymer soft segments containing terminal azetidine-2,4-dione rings. The speed with which the polymerizations can be carried out make the block copolymers particularly useful for the RIM preparation of molded parts.

Polymer from azetidine-2,4-dione and polyol or polyamine

Polyamide block copolymer from lactam and azetidine-2,4-dione

An improved process for the anionic polymerization of lactams is described. Particular azetidinedione compounds are employed as promoters and their use not only permits low polymerization temperatures but gives rise to faster polymerization reactions than prior art procedures allow. The rapid polymerization of caprolactam in accordance with the present invention makes the process particularly suited to RIM procedures for preparing molded polyamides.

Anionic polymerization of lactam with azetidine-2,4-dione promoter

Copolyamide-imides characterized by thermoplasticity, high heat resistance and high impact resistance are derived by the reaction of 4,4'-methylenebis(phenyl isocyanate), optionally in admixture with a minor amount (up to 10 mole percent) of toluene diisocyanate (2,4-, 2,6-isomers and mixtures), with a mixture of trimellitic acid or anhydride (30-40 mole percent), isophthalic acid (26-44 mole percent) and a C.sub.7-10 aliphatic dicarboxylic acid (balance of 100 mole percent but not greater than 32 mole percent). These polymers are useful as engineering plastics.

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Cheshire, CT, United States of America

Steven J Grossman