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US4455272A
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US
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Method of extruding a polystyrene foam using both a physical blowing agent and water
Assignee: Tenneco Foam Products Co
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Filing: 1982-03-29
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Granted: 1984-06-19
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Expires: 2002-03-29
Abstract
Abstract Forming polystyrene foam by extruding polystyrene, nucleating agent, physical blowing agent, and water where the physical blowing agent and water are injected into extruder to provide blowing system. The product produced has small cells at junction points between membranes of the foam.
Inventors
- 👤 John C. Schubert
- 👤 Edward C. LeDuc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:52
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/12; C08J9/14; C08J9/141; B; B29; B29C; B29C44/00; B29C44/34; B29C44/3442; C08J9/143; C08J9/147; B29K; B29K2025/00; C08J2325/00; Y; Y10; Y10S; Y10S264/00; Y10S264/05; Y10S264/13; Y10S521/00; Y10S521/91
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
47 words
In a process for producing extruded polystyrene foam comprising feeding a mixture comprising styrene polymer and nucleating agent to an extruder, and injecting physical blowing agent into the mixture in the extruder, the improvement comprising also injecting water into the extruder and extruding the resulting foamable mixture.
Claim 2
Dependent Claim
47 words
In a process for producing extruded polystyrene foam comprising feeding a mixture comprising styrene polymer and nucleating agent to an extruder, and injecting physical blowing agent into the mixture in the extruder, the improvement comprising also injecting water into the extruder and extruding the resulting foamable mixture.
Claim 3
Dependent Claim
21 words
The improvement of claim 1 wherein the water and physical blowing agent are supplied to the extruder at a common point.
Claim 4
Dependent Claim
11 words
The improvement of claim 1 wherein said nucleating agent is talc.
Claim 5
Dependent Claim
23 words
The improvement of claim 3 wherein said talc is used in an amount of 0.01 to 0.3 weight percent based on styrene polymer.
Claim 6
Dependent Claim
26 words
The improvement of claim 1 wherein said physical blowing agent is in the range of 0.05 to 0.1 gram mols per 100 grams of styrene polymer.
Claim 7
Dependent Claim
27 words
The improvement of claim 5 wherein said physical blowing agent is selected from the group consisting of hydrocarbons containing 3 to 6 carbon atoms, dichlorodifluoromethane and trichlorofluoromethane.
Claim 8
Dependent Claim
13 words
The improvement of claim 5 wherein said physical blowing agent is normal butane.
Claim 9
Dependent Claim
27 words
The improvement of claim 1 wherein said water is injected in the range of 0.5 to 5 weight percent based on the weight of the styrene polymer.
Claim 10
Dependent Claim
48 words
The process of claim 1 wherein the physical blowing agent is in the range of 0.05 to 0.1 gram mole per 100 grams of styrene polymer and said water is in the range of 0.5 to 5 weight weight percent based on the weight of the styrene polymer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-06-19 | 1987-12-19 | 1988-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-19 | 1991-12-19 | 1992-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-19 | 1995-12-19 | 1996-06-19 | $7700.00 | Window Closed / Lapsed |