| 摘要 |
PURPOSE:To obtain a molded product whose surface skin is beautiful by eliminating generation of a line on parison, by a method wherein the parison is cut off from air always by coating a boundry part between a die head and the parison to be extruded with inactive gas. CONSTITUTION:The inside of a first compartment 3 made into a shut up room by closing catchers 6 is filled with argon gas as inactive gas (b) by sending in the argon gas through an air pipe 5 by actuating a circulating device 4. When a resin material (d) is extruded through a die head 2 of an accumulator 1 under this state, parison (a) begins to descend within the first compartment 3 while the parison is being kept cut off. When end parts of the parison (a) are approached to the bottom 3a, the catchers 6 are opened and when the end parts of the parison (a) come outside a little, the catchers 6 are closed again and the end parts of the parison (a) are put between the catchers for join. Although the first compartment 3 is communicated with the outside through an opening 3b at the time when the catchers 6 are opened, as the inside of the first compartment 3 is filled with the argon gas (b) and high-pressure than open air, air neither enters into the first compartment 3 nor comes into contact with a boundary part between the die head 2 and the parison (a). |
