Water-injection foaming devolatilizing method
US5630968A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | May 20, 1997 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/812
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A water-injection foaming devolatilizing method includes the steps of: melting and kneading a polymer in a water-injection dispersing zone of an extruder having a screw; injecting water into a polymer melt so as to be dispersed into the polymer melt which is being kneaded; and vaporizing volatile components contained in the polymer melt together with water in a devolatilizing zone having a vent port and located on a downstream side of the water-injection dispersing zone, so that the volatile components are removed and discharged through the vent port. A pressure-reducing expansion zone is provided between the water-injection dispersing zone and the devolatilizing zone so as to be upstream of the vent port. The method further includes gradually reducing a pressure in the pressure-reducing expansion zone so that not only bubbles in the water which is dispersed into the polymer melt are made to grow up, but also the bubbles are broken down at a downstream end portion of the pressure-reducing expansion zone.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.