US3816233A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of urethane foam sheets
Assignee: Specialty Converters Inc
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Filing: 1972-12-14
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Granted: 1974-06-11
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Expires: 1992-12-14
Abstract
Abstract This invention relates to a novel, porous integral polyurethane sheet wherein one side of the sheet, is of a high density, porous structure and the body of the sheet is a low density, open cell urethane foam. The invention provides a method of making such sheet which comprises differentially heating at least one side of a cast sheet of polyurethane foam mix relative to the body thereof during expansion, then compressing the expanded differentially heated, partially cured foam structure to achieve differential compression and a high density structure on the heated side.
Inventors
- 👤 W Powers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:03
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/34; B29C44/56; B29C44/5627; B29C44/5636; B29C44/5645; B29C44/20; B29C44/22; B29C44/30; C; C08; C08J; C08J9/00; B29C43/00; B29C43/32; B29C43/44; B29C43/46; B29K; B29K2105/00; B29K2105/04; B29L; B29L2007/00; B29L2009/00; C08J2375/00; C08J2375/04; Y; Y10; Y10S; Y10S264/00; Y10S264/14; Y10S521/00; Y10S521/918; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/24992; Y10T428/249921; Y10T428/249953; Y10T428/249975; Y10T428/249981; Y10T428/26; Y10T428/263; Y10T428/264
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
58 words
A uniform integral gas permeable foamed polyurethane sheet according to claim 1 wherein the cell volume is from about 25 percent to about 75 percent per unit volume of foam adjacent the high density side of the sheet and the cell volume is greater than 90 percent per unit volume of foam adjacent the body of the sheet.
Claim 2
Dependent Claim
30 words
A uniform integral gas permeable foamed polyurethane sheet according to claim 1 wherein the relatively low density body of the sheet forms the surface thereof opposite the high density side.
Claim 3
Dependent Claim
102 words
A gas permeable foamed uniform polyurethane sheet comprising a single layer structure having a skin of substantial thickness at at least one face thereof integrally formed with but distinct from a foamed main body, said skin being a foam having a density at least twice that of the body, said skin being characterized by having its closed cells deformed to a flattened shape such that the cell dimension normal to the plane of the sheet is substantially less than half the average dimension of the cells measured in the plane of the sheet, the cells of the body foam being substantiAlly isometric.
Claim 4
Dependent Claim
26 words
A gas permeable foamed polyurethane sheet according to claim 4 wherein the skin has a thickness in the range from about 0.003 inch to 0.075 inch.
Claim 5
Dependent Claim
26 words
A gas permeable foamed polyurethane sheet according to claim 4 wherein the skin constitutes from 10 to 60 percent of the total thickness of the sheet.
References Cited (Backward Citations)
US2908943A
Cited
US3384531A
Cited
US3306967A
Cited
US3328225A
Cited
US3391051A
Cited
US3396419A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |