Annular cooling device for manufacture of tubular film
Abstract
Abstract IN THE MANUFACTURE OF A FILM OF A THERMOPLASTIC RESIN ACCORDING TO AN INFLATION METHOD, THE IMPROVEMENT WHICH COMPRISES EXTRUDING A MOLTEN RESIN FROM AN ANNULAR DIE, COOLING PRELIMINARILY THUS EXTRUDED RESIN WITH A GASEOUS COOLANT TO NOT LOWER THAN THE SOFTENING POINT OF SAID RESIN, INFLATING PRELIMINARILY THUS COOLED RESIN BY AIR HAVING REDUCED PRESSURE, COOLING THUS INFLATED RESIN WITH A GASEOUS COOLANT RAPIDLY TO BELOW THE SOFTENING POINT OF SAID RESIN WHILE FURTHER INFLATING THE SAME TO A PREDETERMINED DIMENSION BY A GASEOUS MEDIUM SEALED IN THE RESULTNG TUBULAR FILM OF SAID RESIN AND FIXING THE DIMENSION OF THE RESULTING TUBULAR FILM AT THE PREDETERMINED POINT. THERE IS ALSO DISCLOSED AN ANNULAR COOLING DEVICE EMPLOYED IN THE MANUFACTURE OF THE TUBULAR FILM.
Inventors
- 👤 Kohei Masuda
- 👤 Kazumasa Hasegawa
- 👤 Akio Okamoto
Bibliographic Details
Claims Analysis
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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) | 1974-03-08 | 1974-09-07 | 1975-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-08 | 1978-09-07 | 1979-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-08 | 1982-09-07 | 1983-03-09 | $7700.00 | Window Closed / Lapsed |