Mold sulfonation system
US4861250A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 29, 1988 |
| Grant date | Aug 29, 1989 |
| Priority date | — |
| Expiry date | Aug 29, 2008 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29L2031/7172
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An in-mold sulfonation system for sulfonating the surface of plastic articles such as plastic containers during molding. Sulfur trioxide is introduced into a pre-mold chamber, converted to a relatively high pressure gaseous sulfur trioxide, and then injected into a mold such as a blow mold immediately before or immediately following full expansion of the formed plastic article in the mold cavity. Neutralization with a gaseous neutralizing agent follows. By controlling the timing and temperature of the in-mold sulfonation step it is possible to produce a plastic article having an effective barrier layer but containing a minimum of undesirable rinseable salts.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.