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US 4,992,222 AGranted
Method for removing volatile substances from polyphenylene ether or polyphenylene ether/styrene resin compositions
AssigneeGeneral Electric Company
InventorsJohn P. Banevicius, Alexandros Hasson, William E. Pecak
Life of this patent
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Abstract
Volatile substances in polyphenylene ether or polyphenylene ether/polystyrene compositions are substantially reduced by extruding the resins in a single pass using a plurality of stages including water injection and vacuum venting.
Claims36
A process for the reduction of volatile substances in a composition comprising
- (a) a polyphenylene ether resin, alone, or in combination with
- (b) a styrene resin, said composition comprising impurities selected from styrene monomer, toluene, volatile odoriferous oxygenated species, sources of volatile odoriferous amines, mixtures of any of them and the like, said process comprising extruding said composition at a temperature above its melting point in one pass in at least two stages, each said stage comprising water injection followed by vacuum venting, the total amount of water being divided between said stages and comprising up to about 15 percent by weight of said composition whereby the devolatilization efficiency of both toluene and trimethylanisole is greater than about 70 percent in comparison with the reduction obtained with the same composition in one pass in a single stage employing the same amount of water.
In a process for the reduction of volatile substances in a composition comprising
- (a) a polyphenylene ether resin, alone, or in combination with
- (b) a styrene resin, said composition comprising impurities selected from styrene monomer, toluene, volatile odoriferous oxygenated species, sources of volatile odoriferous amines, mixtures of any of them, and the like;
- said process comprising extruding said composition at a temperature above about 280.degree. C. in one pass in the presence of water followed by vacuum venting, the improvement which comprises carrying out the process in at least two stages each said stage comprising water injection followed by vacuum venting, the total amount of water being divided between said stages and comprising up to about 15 percent by weight of said composition, whereby the devolatilization efficiency of both toluene and trimethylanisole is greater than about 70 percent in comparison with the reductions obtained with the same composition in one pass in a single stage employing the same amount of water.
Dependencies are inferred from the claim text.