Method to prepare blown films of vinyl aromatic/conjugated diolefin block copolymer
US5658526A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 1, 1995 |
| Grant date | Aug 19, 1997 |
| Priority date | — |
| Expiry date | Nov 1, 2015 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29K2096/04
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method is provided to produce a blown film of a vinyl aromatic/conjugated block copolymer, the method including the steps of: PA1 providing an elastomeric composition, the composition comprising a block copolymer of vinyl aromatic and a conjugated block copolymer; PA1 melting the composition in an extruder; PA1 passing the melted composition from the extruder through a die, the die being a circular die comprising a circular outlet and a tapered channel leading to the circular outlet, the circular outlet having an opening width of about 10.sup.-2 inches, the taper being a linear taper of at least a one inch length, the center of the linear taper being angled away from the center of the circular outlet at an angle of at least 10.degree. from a line normal to the circular outlet, and the die having a source of gas pressure inside of the circular outlet; and PA1 cooling the extruded composition that has been passed through the die with a cooling gas stream.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.