| 摘要 |
PROBLEM TO BE SOLVED: To stabilize molding properties such as a plasticizing time and a metering property and to improve the quality of a molded article by a method wherein carbon dioxide and thermoplastic resin supplied from a material supply port of an injection molding machine are melted and mixed and then subjected to injection molding processing. SOLUTION: A molding machine has a constitution wherein a hopper 4 holding thermoplastic resin 11 is mounted on a heating cylinder 6 with a screw 5 provided inside and a joining part of the hopper functions as a material supply port 3. Carbon dioxide is introduced, in a gaseous state, from a cylinder 1 of the carbon dioxide of purity 99% or above through a gas supply passage 2 assembled from a piping of a diameter 2 mm, and it is supplied from right above into the heating cylinder 6 together with the material. In this contrivance, the screw 5 moves backward with rotation and plasticization and metering of resin are conducted. After metering, the resin is injected to be molded into a cavity 9 of molds 10 from a nozzle 8 by a cylinder 7 for injection. |
