Laminates of polypropylene and polyamide
Abstract
Abstract IMPROVEMENT IN SANDWICH-TYPE POLYPROPYLENE/POLYAMIDE LAMINATES CONSISTING OF A ALYER OF A MIXTURE OF POLYPROPYLENE (PP) AND POLYAMIDE (PA) (LAYER 2) SANDWICHED BETWEEN OUTER LAYERS 1 AND 3 OF POLYPROPYLENE AND POLYAMIDE RESPECTIVELY. THE IMPROVEMENT CONSISTS IN THAT (A) THE POLYPROPYLENE (PP) USED IS A SPECIFIC MIXTURE OF (A) A POLYPROPYLENE OF WHICH LESS THAN 1% BY WEIGHT IS SOLUBLE IN BOILING TOLUENE AND (B) A POLYPROPYLENE OF WHICH MORE THAN 99% BY WEIGHT IS SOLUBLE IN BOILING TOLUENE, PROVIDED THAT THE POLYPROPYLENES (A) AND (B) HAVE (SUBSTANTIALLY) THE SAME INTRINSIC VISCOSITIES, (SUBSTANTIALLY) THE SAME MOLECULAR WEIGHT DISTRIBUTIONS AND SPECIFICE INTRINSIC VISCOSITIES (N), AND (B) THE POLYAMIDE (PA) IS A POLYCAPROLACTAM HAVING A SPCEIFIC VISCOSITY AND SPECIFIC MELTING POINT. THE LAMINATES OF THE INVENTION HAVE IMPROVED PERMEABILITY TO WATER VAPOR, RELATIVELY LOWER PERMEABILTYITY TO OXYGEN AND RELATIVELY HIGH STIFFNESS AND ARE THEREFORE PARTICULARLY SUITABLE FOR PACKAGING FOODSTUFFS.
Inventors
- 👤 A Hofmann
- 👤 H Weiss
Bibliographic Details
Claims Analysis
Total Claims: 0References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |