| 摘要 |
<p>PURPOSE:To control drawdown of a parison, enhance its moldability and simultaneously enhance its transfer properties to a mold by constituting cylindrical passageways in injection dies to be multiple passageways formed concentrically and injecting resin materials under the condition where a temperature of resin to be fed into the outermost passageway of the multiple passageways is increased higher than that of resin to be fed into the inside passageway as a main material. CONSTITUTION:In injection dies 10, cylindrical passageways 18 are constituted to be multiple passageways formed concentrically and joined to each other at a portion disposed immediately before a resin outlet port 24 so as to make it possible to inject a multi-layer parison. A parison 36 is injected by using the parison injection dies 10; however, the same kind of resin is used as a resin material, and a temperature of resin to be filled in an outer cylindrical passageway 18B of double passageways is increased by 10 to 20 deg.C higher than that of resin to be filled in an inner cylindrical passageway 18A, thus injecting the resin materials under the condition of giving them differences in their temperatures.</p> |
