Process for forming plasticized polyvinyl butyral sheet
US5137673A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 17, 1987 |
| Grant date | Aug 11, 1992 |
| Priority date | — |
| Expiry date | Nov 17, 2007 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2948/92971
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Plasticized polyvinyl butyral sheet optionally containing a gradient color band is formed by continuously extruding a sheet having a predetermined region across its width formed from melt issuing from a die at an increased mass flow rate in comparison with other portions of the melt forming the rest of the sheet and then forwardly distorting such sheet immediately after forming by preferentially stretching the side containing the predetermined region to form an arcuate shape of substantially uniform thickness. Arcuately shaped sections are then cut from the sheet to form discrete, shaped interlayer blanks having improved thickness uniformity and dimensional stability providing improved performance when used in laminated safety glass.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.