| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a controlling method of a cyclic oligomer content produced in a PET polyester chip and its processing moldings. <P>SOLUTION: In a producing process of polyethylene terephthalate (PET), the process comprises adding to reactants at least one selected from a calcium phosphate having a structure of Ca<SB>3</SB>(PO<SB>4</SB>)<SB>2</SB>or Ca<SB>5</SB>OH(PO<SB>4</SB>)<SB>3</SB>and a carboxyphosphonic acid with a structure represented by formula (1) (wherein R<SB>1</SB>, R<SB>2</SB>, and R<SB>3</SB>are each an alkyl group or a hydrogen atom; R is an alkyl group) to effectively control a produced amount of the cyclic oligomer in the polyester chip, and to reduce the produced amount of the cyclic oligomer upon a melt processing of a subsequent process. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
