| 摘要 |
PROBLEM TO BE SOLVED: To obtain a hollow injection-molded article in which a hollow part and ribs for supporting the surface and the back are formed, the ribs small in thickness and its deflection are formed densely, and the surface is free from unnecessary unevenness, gloss nonuniformity, and color nonuniformity. SOLUTION: A mold 1 in which the volume of a mold cavity 2 can be changed by moving a movable mold 1a is used. While the cooling of a molten resin which is injected/packed in the cavity 2 whose volume is reduced is partially retarded, pressurized fluid is injected into the molten resin the cooling of which is retarded to form a tunnel-shaped hollow part 4. Next, while the fluid is injected, the movable mold 1a is moved back to increase the volume of the cavity 2 so that a leaf-shaped hollow part 10 connected to the tunnel- shaped hollow part 4 is formed with leaf vein-shaped ribs 9 branching irregularly left.
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