PURPOSE: To manufacture the product of the composite material which includes more wooden powder than resin and can float on the water, by injecting a specified material into a mold, reducing the pressure in the mold, thereby aiding the expansion of the resin.
CONSTITUTION: The composite material is formed by compounding a wooden material and plastics. The weight of the wooden part is the same as or heavier than that of the plastics. The specific gravity of the molded product is 1.0 or less. The specific gravity of the resin of the composite material is 0.9 or less. Hydraulic fluid is supplied through a hydraulic fluid port 18 in advance, and a main rum 13 is advanced. Then a rod 9 is advanced and penetrated into a thick part of a cavity 7, which is to become the product. The volume of the cavity 7 is made smaller than normal. A fused material is injected from a spool 2 and the cavity 7 is filled. When the pressure in a pressure generating chamber 14 is reduced, the rod 9 is moved back. Then the pressure in the cavity 7 in the mold is decreased and a vacuum state is locally obtained. Therefore the material is readily expanded locally. When a quick cooling medium 23 is supplied to a quick cooling port 22, vacuum bubbles are generated in the inside, and the low density is obtained. Then the perfectly hardened product is obtained after the cooling and hardening time.
SANO YASABUROU
MATSUDA SHIYOUJI
SANO YASABUROU
MATSUDA SHOJI