Method for the manufacture of thermoplastic resin sheets
US5151234A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 29, 1990 |
| Grant date | Sep 29, 1992 |
| Priority date | — |
| Expiry date | Mar 29, 2010 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C48/001
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method for the manufacture of thermoplastic resin sheets, including extruding molten thermoplastic resin at an extrusion velocity V through a slit provided in an extrusion mold so as to form thermoplastic resin sheets with embossed surfaces, wherein said thermoplastic resin is extruded from said slit in said extrusion mold under conditions such that the ratio V/H of said extrusion velocity V to the width H of said slit exceeds a critical value (V/H)c, said critical value (V/H)c being the ratio of the extrusion velocity to the width of the mold slit corresponding minimum value of the roughness of the embossment formed on the surface of said thermoplastic resin sheets, whereby defects such as the adhesion to and winding onto rollers, inferior appearance and sizing marks which are prone to occur when the sheets are embossed with embossing rollers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.