Process for preparing gas-, vapor- and odor-proof coupled and coextruded multilayer articles of thermoplastic material and closed-surface bodies comprising the same
US4244914A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jun 5, 1978 |
| Grant date | Jan 13, 1981 |
| Priority date | — |
| Expiry date | Jun 5, 1998 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/1379
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
There is disclosed a new process for preparing coupled and coextruded multilayer articles (consisting of two or more layers) made of thermoplastic materials, and closed-surface bodies comprising the same. PA1 The process comprises PA1 (a) feeding, to an extruder connected with a coextrusion head, a polyvinyl alcohol having a high degree of hydrolysis mixed with an aqueous mixture of plasticizing compounds and heated under pressure to bring it to the plastisol state; PA1 (b) subjecting the plastisol polyvinyl alcohol to rapid decompression with simultaneous venting of the evolved vapors, before it enters the coextrusion head and while it is at a temperature at least equal to, and preferably higher than, the temperature of the coextrusion head; PA1 (c) separately feeding at least one other thermoplastic polymer to the same coextrusion head; PA1 (d) adjusting the temperature of the polymers, after contact thereof, so that the temperature of the polyvinyl alcohol is at least equal to, and preferably higher than, the temperature of the other coextruded polymer or polymers; PA1 (e) adjusting the flow rate of the polymers so that the outflow linear velocities thereof are equal or differ n…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.