Addition method of supercritical carbon dioxide, and production process of expanded thermoplastic resin product by making use of the addition method
US6328916A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 12, 1999 |
| Grant date | Dec 11, 2001 |
| Priority date | — |
| Expiry date | Jul 12, 2019 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C44/3446
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
This invention provides a method for stably adding a predetermined amount of supercritical carbon dioxide at a fixed delivery rate into a forming machine and also a process for producing an expanded thermoplastic resin product by making use of the addition method. Carbon dioxide is charged from a liquefied carbon dioxide cylinder (1) into a predetermined amount deliverable pump (2) while allowing the carbon dioxide to remain in a liquefied state. When the carbon dioxide is pressurized and delivered by the predetermined amount deliverable pump (2), a delivery pressure of the carbon dioxide is controlled at an optional pressure within a range of from a critical pressure (7.4 MPa) of carbon dioxide to 40 MPa to deliver the carbon dioxide without any fluctuation of the amount of the delivery by setting up the pressure of a pressure control valve (3). The carbon dioxide is heated to a critical temperature (31.degree. C.) of carbon dioxide or higher to convert it into supercritical carbon dioxide. This supercritical carbon dioxide is then added to a molten thermoplastic resin in the forming machine (4).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.