| 摘要 |
PURPOSE:To obtain a new copolymerized polyester giving a heat-shrinkable film having large maximum value of shrinkage factor, excellent low-temperature shrinkability and good appearance in shrunk state, and useful as a covering material, a binding material, a sheathing material, etc. CONSTITUTION:This copolymerized polyester is composed mainly of (A) a constituent unit of formula I, (B) a constituent unit of formula II, (C) a constituent unit of formula III and (D) a constituent unit of formula IV (A and B each is H or methyl and at least one of A and B is H) and satisfies the molar ratios of A/B=995/5 to 900/100, C/D=95/5 to os/as and (4B+D)/(A+B+C+D):10/200 to 50/200. It has a glass transition temperature of 40-80 deg.C and an intrinsic viscosity of >=0.4dL/g [measured in 1:1 (weight ratio) mixture of phenol and tetrachloroethane at 30 deg.C]. The polymer can be produced by introducing respective prescribed amounts of comonomer units corresponding to the constituent units B to D into a PET molecule. |
