Patent ID: 6328916
Filing Date: 2001-12-11
Classification: B29C

Abstract:
A method for the addition of supercritical carbon dioxide to a molten thermoplastic resin, which comprises charging carbon dioxide from a liquefied carbon dioxide cylinder (1) into a predetermined amount deliverable pump (2) while allowing said carbon dioxide to remain in a liquefied state, delivering said carbon dioxide from said predetermined amount deliverable pump (2) in such a manner that, when said carbon dioxide is pressurized and delivered by said predetermined amount deliverable pump (2), a delivery pressure is controlled at an optional pressure in a range of from a critical pressure (7.4 MPa) of carbon dioxide to 40 MPa to deliver said carbon dioxide without any fluctuation of the amount of the delivery by setting up the pressure of a pressure control valve (3), heating said carbon dioxide to a critical temperature (31.degree. C.) of carbon dioxide or higher to convert said carbon dioxide into supercritical carbon dioxide, and then adding said supercritical carbon dioxide to said molten thermoplastic resin into a forming machine.