Butyl elastomeric compositions having reduced permeability to gases
AssigneePolysar Limited
InventorSheikh A. H. Mohammed
Life of this patent
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Abstract
A new rubber composition, the vulcanizate of which has reduced permeability to gases, comprises: one hundred parts by weight of at least one butyl-type rubbery polymer; from about 3 to about 20 parts by weight of .alpha.-methylstyrene homopolymer having a softening point of from about 93.degree. C. to about 150.degree. C. and a Tg of from about 15.degree. C. to about 75.degree. C.; from about 30 to about 90 parts by weight of at least one carbon black, from 0 to about 7 parts by weight of hydrocarbon extender oil; and a curing system. A process for producing said rubber composition is also provided.
Claims24
A new rubber composition, the vulcanizate of which has reduced permeability to gases, comprising:
- one hundred parts by weight of at least one rubbery polymer selected from the group consisting of butyl rubber, chlorinated butyl rubber and brominated butyl rubber,
- from about 3 to about 20 parts by weight of .alpha.-methylstyrene homopolymer having a softening point of from about 93.degree. C. to about 150.degree. C. and a Tg of from about 15.degree. C. to about 75.degree. C.,
- from about 30 to about 90 parts by weight of at least one carbon black,
- from 0 to about 7 parts by weight of hydrocarbon extender oil, and
- a curing system.
A process for producing a vulcanizate having reduced permeability to gases which comprises:
- (A) mixing one hundred parts by weight of at least one rubbery polymer selected from the group consisting of butyl rubber, chlorinated butyl rubber and brominated butyl rubber with an .alpha.-methylstyrene homopolymer, wherein said .alpha.-methylstyrene homopolymer is used in an amount of from about 3 to about 20 parts by weight and has a softening point of from about 93.degree. C. to about 150.degree. C. and a Tg of from about 15.degree. C. to about 75.degree. C., from about 30 to about 90 parts by weight of at least one carbon black, from 0 to about 7 parts by weight of hydrocarbon extender oil, and a curing system,
- (B) forming the mixture produced in (A) into a sheet, and
- (C) vulcanizing the sheet formed in (B) at a temperature of from about 150.degree. C. for from about 5 to about 60 minutes.
Dependencies are inferred from the claim text.