| 摘要 |
PURPOSE:To prevent generation of thermal oxidation or yellowing due to the same effectively without depending upon an antioxidant, by a method wherein inactive gas is introduced within a cylinder and plasticization of resin is advanced within an atmosphere. CONSTITUTION:A gas introduction hole 10, for example, is provided in the bottom of a hopper 6 and inactive gas such as nitrogen gas is fed within a cylinder 1 continuously through a gas cylinder 11. With this construction, plasticization of resin is advanced within an atmosphere of the inactive gas, the resin and oxygen do not come into contact with each other during. plasticizing process, progress of radical chain reaction generating thermal oxidation is obstructed with the result that neither the thermal oxidation nor yellowing due to the thermal oxidation is generated. |
