| 摘要 |
PURPOSE: To obtain a molding material compsn. which has a high specific gravity, is uniformly colored in milk white, and gives a nucleating agent for pearl culture excellent in affinity for mother shellfishes by compounding a polyester resin having a specified Hazen color number with barium sulfate having a specified particle size and anα-amino acid. CONSTITUTION: This compsn. is prepd. by homogeneously mixing, under heating, 100 pts.wt. polyester resin having a Hazen color number of 500 or lower in the molten or liq. state with 200-600 pts.wt. barium sulfate having an average primary particle size of 0.5μm or lower and 0.1-100 pts.wt.α-amino acid. The compsn. is molded into desired shapes by transfer or injection molding in such a manner as to give a molding having a specified gravity of 2.0 or higher. Thus obtd. nucleating agent for pearl culture has a high specific gravity, is uniformly colored in milk white with some transparency, and is excellent in mechanical strengths and affinity for mother shellfishes.
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