| 摘要 |
PROBLEM TO BE SOLVED: To make injection molding of a product being the same as a crystalline polyethylene terephthalate possible by decreasing water content of a ground polyethylene terephthalate material to a water content which does not generate excess steam in a heating cylinder by drying, and performing plasticization and deaeration by suction of the ground material as a molding material by a vent type injection apparatus. SOLUTION: The ground polyethylene terephthalate material is molded into a molded article with an arbitrary shape by using the vent type injection apparatus. After the water content of the ground material is decreased to a water content of≤0.05 wt.%, preferably 0.04-0.02 wt.% by a dryer, plasticization and deaeration by suction are performed. The ground material with a water content of≤0.6 wt.% requires a drying time of≥2 hr at a set temperature of 120°C to lower than 140°C for decreasing the water content by the dryer. The drying is performed by making the total amount corresponding to the amount for at least 2 hours of the weight of the product molded by one shot as a unit. COPYRIGHT: (C)2004,JPO |
