Method for reducing the monomer content in acrylonitrile containing polymers
AssigneeRadiation Dynamics, Inc.
InventorKennard H. Morganstern
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Abstract
The monomer content in acrylonitrile containing polymers, as for example bottles formed from acrylonitrile/styrene copolymer, is substantially reduced by applying ionizing radiation at conventional rates in low dosage levels.
Claims16
A method for reducing the acrylonitrile monomer content in an acrylonitrile polymer which comprises exposing the polymer to ionizing radiation at an irradiation dosage level of from about 0.050-2.0 megarads at a rate sufficient to significantly reduce the extractable residual acrylonitrile monomer content in the polymer, wherein the polymer is not at or above its softening point during exposure to said ionizing radiation.
A method for reducing the acrylonitrile monomer content in an acrylonitrile polymer which comprises exposing the polymer to ionizing radiation at an irradiation dosage level of from about 0.050-2.0 megarads at a rate sufficient to significantly reduce the extractable residual acrylonitrile monomer content in the polymer, wherein said acrylonitrile polymer is a copolymer comprised of from 55-85% by weight (of the total polymer weight) of acrylonitrile alone or acrylonitrile and methacrylonitrile in amounts up to 16% by weight (of the total polymer weight) and one or more comonomers selected from the group consisting of styrene, alpha methylstyrene, alpha olefins of 2-6 carbon atoms, C.sub.1 -C.sub.4 akyl esters of acrylic and methacrylic acid, vinyl acetate, and C.sub.1 -C.sub.4 alkyl vinyl esters.
A method for reducing the acrylonitrile monomer content in an acrylonitrile polymer which comprises exposing the polymer to ionizing radiation at an irradiation dosage level of from about 0.050-2.0 megarads at a rate sufficient to significantly reduce the extractable residual acrylonitrile monomer content in the polymer, wherein said polymer is a formed bottle or jar comprised of 60-83% by weight acrylonitrile.
A method for reducing the acrylonitrile monomer content in an acrylonitrile polymer comprising, providing the polymer to be treated in the form of a ground resin or pellet, exposing said polymer while in said ground resin or pellet form to a first dosage of ionizing radiation, thereafter forming the polymer into a finished article and exposing the polymer while in said finished article form to a second dosage of ionizing radiation, the total dosage of ionizing radiation not exceeding about 0.050-2.0 megarads.
Dependencies are inferred from the claim text.