US3855378A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing cellular rubber
Assignee: Cities Service Co
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Filing: 1973-06-28
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Granted: 1974-12-17
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Expires: 1993-06-28
Abstract
Abstract Closed-cell expanded rubber having a uniform cell structure is prepared by partially curing a vulcanizable rubber in the presence of a vulcanizing agent and a blowing agent at a temperature lower than that at which substantial decomposition of the blowing agent occurs and subsequently expanding and completing the cure of the partially cured rubber. If desired, the compositions which are treated in accordance with the invention may contain thermoplastic resins, antioxidants, processing aids, fillers, and other ingredients conventionally used in vulcanizable rubber compositions. According to a preferred embodiment of the invention, the rubber is butyl rubber or a mixture thereof with ethylene-propylene-diene terpolymer.
Inventors
- 👤 B Topcik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:18
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/06; C08J2321/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
152 words
IN A PROCESS FOR PREPARING A CELLULAR RUBBER BY HEATING A COMPOSITION COMPRISING (A) A VULCNIZABLE RUBBER SELECTED FROM THE GROUP CONSISTING OF BUTYL RUBBER, CHLORINATED BUTYL RUBBER, BROMINATED BUTYL RUBBER, ETHYLENE-PROPYLENE COPOLYMER, ETHYLENE-PROPYLENE-DIENE TERPOLYMER, CHLOROSULFONATED POLYETHYLENE, NEUTRAL RUBBER, SYNTHETIC POLYISOPRENE, POLYBUTADIENE, BUTADIENE-STYRENE COPOLYMER, BUTADIENE-ACRYLONITRILE COPOLYMER, POLYCHLOROPRENE, POLYEPICHLOROHYDRIN, EPICHLOROHYDRIN-ETHYLENE OXIDE COPOLYMER, AND MIXTURES THEREOF, (B) A VULCANIZING AGENT, AND (C) A BLOWING AGENT TO CURE AND EXPAND THE RUBBER, THE IMPROVEMENT WHICH COMPRISES INITIATING OF THE RUBBER BY HEATING THE COMPOSITION UNDER A PRESSURE OF ABOUT 1,00-2,000 PSI IN A MOLD AT A TEMPERATURE WITHIN THE RANGE OF ABOUT 220*-400*F, WHICH IS LOWER THAN THAT AT WHICH SUBSTANTIAL DECOMPOSITION OF THE BLOWING AGENT OCCURS, REMOVING THE PARTIALLY CURED RUBBER COMPOSITION FROM THE MOLD, AND COMPLETING CURE OF THE RUBBER AT A HIGHER TEMPERATURE WITHIN THE RANGE OF ABOUT 300*-420*F, WHICH PERMITS SUBSTANTIAL DECOMPOSITION OF THE BLOWING AGENT AND EXPANSION OF THE COMPOSITION.
Claim 2
Dependent Claim
152 words
IN A PROCESS FOR PREPARING A CELLULAR RUBBER BY HEATING A COMPOSITION COMPRISING (A) A VULCNIZABLE RUBBER SELECTED FROM THE GROUP CONSISTING OF BUTYL RUBBER, CHLORINATED BUTYL RUBBER, BROMINATED BUTYL RUBBER, ETHYLENE-PROPYLENE COPOLYMER, ETHYLENE-PROPYLENE-DIENE TERPOLYMER, CHLOROSULFONATED POLYETHYLENE, NEUTRAL RUBBER, SYNTHETIC POLYISOPRENE, POLYBUTADIENE, BUTADIENE-STYRENE COPOLYMER, BUTADIENE-ACRYLONITRILE COPOLYMER, POLYCHLOROPRENE, POLYEPICHLOROHYDRIN, EPICHLOROHYDRIN-ETHYLENE OXIDE COPOLYMER, AND MIXTURES THEREOF, (B) A VULCANIZING AGENT, AND (C) A BLOWING AGENT TO CURE AND EXPAND THE RUBBER, THE IMPROVEMENT WHICH COMPRISES INITIATING OF THE RUBBER BY HEATING THE COMPOSITION UNDER A PRESSURE OF ABOUT 1,00-2,000 PSI IN A MOLD AT A TEMPERATURE WITHIN THE RANGE OF ABOUT 220*-400*F, WHICH IS LOWER THAN THAT AT WHICH SUBSTANTIAL DECOMPOSITION OF THE BLOWING AGENT OCCURS, REMOVING THE PARTIALLY CURED RUBBER COMPOSITION FROM THE MOLD, AND COMPLETING CURE OF THE RUBBER AT A HIGHER TEMPERATURE WITHIN THE RANGE OF ABOUT 300*-420*F, WHICH PERMITS SUBSTANTIAL DECOMPOSITION OF THE BLOWING AGENT AND EXPANSION OF THE COMPOSITION.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein the vulcanizable rubber is butyl rubber.
Claim 4
Dependent Claim
18 words
The process of claim 1 wherein the vulcanizable rubber is a mixture of butyl rubber and ethylene-propylene-diene terpolymer.
Claim 5
Dependent Claim
68 words
The process of claim 1 wherein the composition additionally comprises up to 80 percent by weight of a compatible thermoplastic resin, based on the combined weights of rubber and resin; said thermoplastic resin being selected from the group consisting of polyethylene, ethylene-vinyl acetate copolymer, chlorinated polyethylene, polypropylene, polybutylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer, polyvinyl ether, polystyrene, styrene-butadiene copolymer, and mixtures thereof.
Claim 6
Dependent Claim
11 words
The process of claim 4 wherein the thermoplastic resin is polyethylene.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-16 | 1978-06-17 | 1978-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-16 | 1982-06-17 | 1982-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-16 | 1986-06-17 | 1986-12-17 | $7700.00 | Window Closed / Lapsed |