Browse Prior Art Database

SYNTHETIC METHOD FOR REDUCING VOLATILE IMPURITIES IN POLYMERS

IP.com Disclosure Number: IPCOM000026461D
Original Publication Date: 1992-Feb-29
Included in the Prior Art Database: 2004-Apr-05
Document File: 2 page(s) / 85K

Publishing Venue

Xerox Disclosure Journal

Abstract

In US. Patent 4,558,108 issued December 10, 1985, a novel method for reducing the residual unpolymerized butadiene in a styrene-butadiene copolymer is described in which a "venting" procedure is utilized during polymerization, but before the final stage of polymerization. This "venting" method can be applied not only to the styrene-butadiene materials described in the above-mentioned patent, but in all polymerizations where volatile residual monomer impurities should be reduced. It is especially suitable for suspension polymerizations. This "venting" procedure could be employed for any suitable polymer system or polymerization method but is particularly suitable in the suspension polymerization or copolymerization of vinyl chloride. In a specific example, the process may include the steps of providing an aqueous phase comprising a mixture of water, emulsifiers and suspension agents and an oil phase comprising a mixture of vinyl chloride monomer, polymerization initiates, chain transfer agents etc:, providing a vapor phase of an inert gas and vinyl chloride monomer, heating the aqueous oil phase and the vapor phase, removing vinyl chloride monomer from the vapor phase after at least about 75 percent by weight of the vinyl chloride monomer in the aqueous phase is converted to a polymer and prior to conversion of more than about 98 percent by weight of the vinyl chloride monomer in the aqueous phase to a polymer, and heating the aqueous phase until about 90 percent by weight of the vinyl chloride monomer is polymerized to form an aqueous suspension of discrete polymer particles.

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XEROX DISCLOSURE JOURNAL

SYNTHETIC METHOD FOR Proposed Classification REDUCING VOLATILE IMPUR- U.S. C1.5261344.2 ITIES IN POLYMERS
Lupu Alexandru

Int. C1. C08f 114/06

In US. Patent 4,558,108 issued December 10, 1985, a novel method for reducing the residual unpolymerized butadiene in a styrene-butadiene copolymer is described in which a "venting" procedure is utilized during polymerization, but before the final stage of polymerization. This "venting" method can be applied not only to the styrene-butadiene materials described in the above-mentioned patent, but in all polymerizations where volatile residual monomer impurities should be reduced. It is especially suitable for suspension polymerizations. This "venting" procedure could be employed for any suitable polymer system or polymerization method but is particularly suitable in the suspension polymerization or copolymerization of vinyl chloride. In a specific example, the process may include the steps of providing an aqueous phase comprising a mixture of water, emulsifiers and suspension agents and an oil phase comprising a mixture of vinyl chloride monomer, polymerization initiates, chain transfer agents etc:, providing a vapor phase of an inert gas and vinyl chloride monomer, heating the aqueous oil phase and the vapor phase, removing vinyl chloride monomer from the vapor phase after at least about 75 percent by weight of the vinyl chloride monomer in the aqueous phase is converted to a polymer and prior to co...