Paper-like thermoplastic film
US4082880A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 23, 1977 |
| Grant date | Apr 4, 1978 |
| Priority date | — |
| Expiry date | May 23, 1997 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29K2995/0081
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A paper-like thermoplastic film and a process for making it are disclosed. The process involves extruding a mixture of (a) 70-98% by weight of a polyethylene having a maximum melt flow index of 5 decigrams per minute and (b) 2-30% by weight of inorganic lamellar filler particles, e.g., mica, the largest dimension of said particles being less than 150 microns, through a circular die, in the form of seamless tubing, continuously withdrawing the tubing from the point of extrusion, and expanding and simultaneously cooling the tubing while in the plastic formative state at a temperature above the melting temperature to a blow up ratio in the range of from 1.2:1 to 10:1.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.