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US4438224A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the preparation of styrene polymer foam and foam prepared thereby
Assignee: Dow Chemical Co
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Filing: 1983-08-15
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Granted: 1984-03-20
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Expires: 2003-08-15
Abstract
Abstract Mechanically stable styrene polymer foams having highly desirable physical properties are prepared employing as a blowing agent a mixture of lower alcohols with chlorofluoromethanes.
Inventors
- 👤 Kyung W. Suh
- 👤 David C. Krueger
- 👤 Burch E. Zehner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:08
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/12; C08J9/14; C08J9/149; C08J2325/00; C08J2325/02; Y; Y10; Y10S; Y10S264/00; Y10S264/05; Y10S521/00; Y10S521/91
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
313 words
A synthetic resinous thermoplastic foam prepared in accordance with the hereinbefore described method wherein an alkenyl aromatic thermoplastic synthetic resinous elongate foam body having a machine direction and a transverse direction, the body defining a plurality of closed noninterconnecting gas-containing cells therein, the cells having an average cell size of from about 0.1 to 1.2 millimeters, the foam body being of a generally uniform cellular structure and being without discontinuities, the body being without substantial variation in average cell size when cell size is measured by averaging cell diameter across the minimum cross-sectional dimension of the body (i.e., such as by ASTM Method D2842-69), the elongate body having a cross-sectional area of at least 8 square inches and having a minimum cross-sectional dimension of at least 0.25 inch, the foam body having a water vapor permeability not greater than 1.8 perm inches as measured by ASTM Method C355-64 Procedures for Desiccant method, a density of from about 1 to about 5 pounds per cubic foot with the further limitation that the cells contain a blowing agent which has a permeability through the alkenyl aromatic resinous polymer of not greater than 0.017 times the permeability of nitrogen through the body, a C 1 to C 3 monohydric alcohol and the blowing agent having a thermal conductivity of 0.08 British thermal units-inch per hour per square foot per degree Fahrenheit, wherein the foam is prepared by extrusion employing a blowing agent selected from the group consisting of (1) a mixture of from about 5 to 20 weight percent isopropyl alcohol, from about 5 to 50 percent chlorodifluoromethane, and from about 30 to 70 percent dichlorodifluoromethane; (2) a mixture of from about 5 to 50 percent of an ethanol, methanol or mixtures thereof, from about 5 to 50 percent of chlorodifluoromethane, and about 30 to 70 percent dichlorodifluoromethane; and mixtures thereof, all percentages being by weight.
Claim 2
Dependent Claim
313 words
A synthetic resinous thermoplastic foam prepared in accordance with the hereinbefore described method wherein an alkenyl aromatic thermoplastic synthetic resinous elongate foam body having a machine direction and a transverse direction, the body defining a plurality of closed noninterconnecting gas-containing cells therein, the cells having an average cell size of from about 0.1 to 1.2 millimeters, the foam body being of a generally uniform cellular structure and being without discontinuities, the body being without substantial variation in average cell size when cell size is measured by averaging cell diameter across the minimum cross-sectional dimension of the body (i.e., such as by ASTM Method D2842-69), the elongate body having a cross-sectional area of at least 8 square inches and having a minimum cross-sectional dimension of at least 0.25 inch, the foam body having a water vapor permeability not greater than 1.8 perm inches as measured by ASTM Method C355-64 Procedures for Desiccant method, a density of from about 1 to about 5 pounds per cubic foot with the further limitation that the cells contain a blowing agent which has a permeability through the alkenyl aromatic resinous polymer of not greater than 0.017 times the permeability of nitrogen through the body, a C 1 to C 3 monohydric alcohol and the blowing agent having a thermal conductivity of 0.08 British thermal units-inch per hour per square foot per degree Fahrenheit, wherein the foam is prepared by extrusion employing a blowing agent selected from the group consisting of (1) a mixture of from about 5 to 20 weight percent isopropyl alcohol, from about 5 to 50 percent chlorodifluoromethane, and from about 30 to 70 percent dichlorodifluoromethane; (2) a mixture of from about 5 to 50 percent of an ethanol, methanol or mixtures thereof, from about 5 to 50 percent of chlorodifluoromethane, and about 30 to 70 percent dichlorodifluoromethane; and mixtures thereof, all percentages being by weight.
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) | 1987-03-20 | 1987-09-19 | 1988-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-20 | 1991-09-19 | 1992-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-20 | 1995-09-19 | 1996-03-20 | $7700.00 | Window Closed / Lapsed |