Patent ID: 7198846

Claim:
A polytrimethylene terephthalate resin comprising: 90 to 100 mole % of trimethylene terephthalate recurring units, and 0 to 10 mole % of at least one monomer unit selected from the group consisting of monomer units obtained from comonomers which are other than the monomers used for forming said trimethylene terephthalate recurring units and which are copolymerizable with at least one of the monomers used for forming said trimethylene terephthalate recurring units, said polytrimethylene terephthalate resin having the following characteristics (A) to (D): (A) an intrinsic viscosity [η] of from 0.8 to 4.0 dl/g; (B) a molecular weight distribution of from 2.0 to 2.7 in terms of the Mw/Mn ratio, wherein Mw represents the weight average molecular weight of said polytrimethylene terephthalate resin and Mn represents the number average molecular weight of said polytrimethylene terephthalate resin; (C) a psychometric lightness L-value (L-1) of from 70 to 100 and a psychometric chroma b*-value (b*-1) of from −5 to 25; and (D) a psychometric lightness L-value (L-2) of from 70 to 100 and a psychometric chroma b*-value (b*-2) of from −5 to 25 as measured after heating said polytrimethylene terephthalate resin at 180° C. for 24 hours in air.