| 摘要 |
Injection moulding of a thermoplastic resin contg. a thermally decomposable blowing agent is carried out by preparing the resin for injection at a temp. below the decomposition temp., and then heating to the decomposition temp. during the ejection of the resin from an injection cylinder and its passage to the mould, the increase in temp. of the resin to the decompn. temp. being obtained through the shear stress arising in the resin ejected from the injection cylinder. The temp. of the mass of resin is increased rapidly and uniformly to the decompn. temp. of the blowing agent during its ejection from the injection cylinder. Injection moulding can be carried out rapidly without overheating the resin in the previous preparation stage. |
