US3689629A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solvent surface treatment of microporous polyurethane elastomer
Assignee: Porvair PLC
•
Filing: 1969-08-15
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Granted: 1972-09-05
•
Expires: 1989-08-15
Abstract
Abstract A microporous polyurethane coating is given an appearance resembling that of calf grain leather by being sprayed with a solvent for the polyurethane, for example N-N dimethylformamide and heating the surface to evaporate the solvent. The preferred spray has a narrow range of droplet sizes defined in the specification.
Inventors
- 👤 Graham Rodney Hull
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:24
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/36; Y; Y10; Y10S; Y10S428/00; Y10S428/904; Y10S521/00; Y10S521/918
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
37 words
Process as in claim 1 in which said flexible sheet used as the starting material has a colored surface and the color of said surface is darkened and made less matt by said solvent deposition and heating.
Claim 2
Dependent Claim
56 words
Process as in claim 2 in which a spray of said solvent is directed at the surface of the sheet and traversed back and forth across the surface of the sheet while the sheet moves transversely to the direction of spraying and a current of heated air is blown at the sprayed surface of the sheet.
Claim 3
Dependent Claim
20 words
Process as in claim 3 in which the current of air is at a temperature of 40* to 100* C.
Claim 4
Dependent Claim
50 words
Process as in claim 2, in which said heating is by a current of heated air at 40* to 100* C., the polyurethane is a linear thermoplastic elastomer having a molecular weight in the range of 20,000 to 300,000 and being soluble in dimethylformamide, and said deposited solvent comprises dimethylformamide.
Claim 5
Dependent Claim
22 words
Process as in claim 5 in which said elastomer is obtained by reacting a linear polyester having hydroxyl groups and a diisocyanate.
Claim 6
Dependent Claim
97 words
Process as in claim 5 in which said microporous soluble polyurethane elastomer surface zone is one obtained, from a mixture of sodium chloride particles of 5 to 25 micron particle size with a solution of said polyurethane elastomer in dimethylformamide, by shaping said mixture, contacting said mixture with water to cause the polyurethane to come out of solution, to remove the dimethylformamide and to extract the sodium chloride, and then drying the shaped mixture to remove the water, said finely divided liquid being applied in such amount and such finely divided form as to indent said surface.
References Cited (Backward Citations)
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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) | 1975-09-05 | 1976-03-06 | 1976-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-05 | 1980-03-06 | 1980-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-05 | 1984-03-06 | 1984-09-05 | $7700.00 | Window Closed / Lapsed |