UNIAXIALLY OR BIAXIALLY STRETCHED POLYESTER RESIN FOAMED SHEET AND FILM

摘要

PROBLEM TO BE SOLVED: To provide uniaxially or biaxially stretched polyester resin foamed sheets and films having a low apparent density and a sufficiently high crystallinity. SOLUTION: This polyester resin foamed sheet has a melt strength of higher than 1 cN at 280 deg.C, a melt viscosity of at least 1,500 Pa.s at 280 deg.C for a shear rate which tends to 0 and a crystallization rate such that heating at 120 deg.C for 10 min gives crystallinity of 30-35%. Desirably, the bulk density is in the range of 100-1,000 kg/m3 and the thickness is 0.03-1 mm.