| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polyester resin improved in surface exterior appearance, flatness stability and mechanical properties of its molding, a polyester resin composition comprising the polyester resin, and extrusion molding thereof. SOLUTION: The polyester resin comprises (A) an acid component mainly comprising telephthatic acid unit, (B) an alcohol component mainly comprising 1,4-butanediol unit, and (C) 0.05-2 mol% of at least one component of at least 3 valent polycarboxylic acid (base on total acid components of 100 mol%) or a polyhydroxy alcohol (based on total alcohol components of 100 mol%). The inherent viscosity [η] of the polyester resin measured at 250 deg.C in a solvent mixture comprising equal amounts of phenol and tetrachloroethane is at least 0.50 di/g and melt tension thereof at 270 deg.C is 0.8-5.0 g.
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