Stauffer Chemical Company

Medtronic, Inc.

Robert H Brunner

Erik R Scott

Paul Kraft

Collette M Vanelzen

Adam F Kopacki

Tri-Cuong Dang

Larry J Gillespie

Fire retardant copolymers of: (1) a bis (hydrocarbyl) vinylphosphonate, (2) a monomer which contains one ethylenically unsaturated bond, and (3) acrylic or methacrylic acid are disclosed. These copolymers are useful in a variety of applications, including as coatings, and as additives for enhancing the fire retardancy of thermoplastics.

Fire retardant copolymers

A process is disclosed for preparing a polyacrylate-modified polyvinyl chloride processing aid for polyvinyl chloride by sequentially polymerizing the vinyl chloride and the desired acrylate ester monomer. Thus, a conventional vinyl chloride suspension polymerization is conducted at a controlled rate of agitation and in the presence of a specified concentration of suspending agent and is then halted at or near its completion; unreacted vinyl chloride monomer is removed, a minor proportion of an acrylate ester monomer, e.g., methyl methacrylate, which has been pre-mixed with a fresh supply of a free radical initiating catalyst is added and polymerization is resumed and continued until the acrylate ester monomer polymerizes in and/or on the particles of the previously polymerized polyvinyl chloride. The polyacrylate-modified PVC thereby recovered is an effective aid for processing conventional PVC, or it can be processed per se since it is suitable for calendering or extruding.

Polymer composition containing processing aid

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Yonkers, NY, United States of America

Robert H Brunner