Production of flat structural sandwich constructions
Abstract
Abstract A process for the production of sandwich constructions consisting of (a) an inner ply of polyethylene; (b) adhesionpromoting interlayers applied to both sides of the inner ply and (c) outer plies of metal applied to the two interlayers. It is a characteristic feature of the invention that sheeting is prepared continuously from a special polyethylene by means of a screw extruder at a specific temperature of the material, this sheeting is covered on both sides with a film of a special polymer by means of a pair of rollers, the resultant laminate is then covered continuously by means of a pair of rollers at a specific temperature of the material with metal sheeting having a specific temperature and the whole is combined to form a sandwich panel under a specific roller pressure. The process gives sandwich constructions having particularly good chemical and physical properties in a simple way.
Inventors
- 👤 Hans Frielingsdorf
- 👤 Heinz Mueller-Tamm
- 👤 Dieter Mahling
Bibliographic Details
Claims Analysis
Total Claims: 6References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |