US3632841A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of stretching acrylic plastics and product
Assignee: TERRY D FORTIN
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Filing: 1970-05-13
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Granted: 1972-01-04
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Expires: 1990-05-13
Abstract
Abstract A METHOD FOR STRETCHING OF AS-CAST ACRYLIC PLASTICS TO PRODUCE STRETCHED ACRYLICS HAVING SUPERIOR OPTICAL AND PHYSICAL PROPERTIES, COMPRISING COMPRESSING AN ACRYLIC PLASTIC BLANK, PREHEATED SUBSTANTIALLY ISOTHERMALLY TO ITS SOFTENING TEMPERATURE RANGE, BETWEEN A PAIR OF CURVED OR FLAT POLISHED ELEMENTS OR PLATES HAVING A FILM OF LUBRICANT COATED THEREON AT A PREDETERMINED THICKNESS-REDUCTION RATE UNTIL THE DESIRED ACRYLIC SHEET THICKNESS IS REACHED AND, THEREAFTER, COOLING THE STRETCHED ACRYLIC SHEET AT A PREDETERMINED RATE TO A TEMPERATURE BELOW ITS SOFTENING TEMPERATURE RANGE PRIOR TO REMOVING THE PRESSURE FROM THE ACRYLIC MATERIALS. D R A W I N G
Inventors
- 👤 Terry D Fortin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:14
CPC Classifications
B; B29; B29C; B29C55/00; B29C55/02; B29B; B29B13/00; B29B13/02; B29B13/023; B29C67/00; Y; Y10; Y10T; Y10T428/00; Y10T428/26
Claims Analysis
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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) | 1975-01-03 | 1975-07-05 | 1976-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-03 | 1979-07-05 | 1980-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-03 | 1983-07-05 | 1984-01-04 | $7700.00 | Window Closed / Lapsed |