abstract |
Mono- or biaxially-stretched polyester resin foamed sheets and films wherein the polyester resin has a melt strength of more than 1 centinewton at 280°C, a melt viscosity of at least 1500 Pa.s at 280°C for a shear ratio which tends to zero and a crystallization rate such that for a 10-minute heating at 120°C the crystallinity can reach values as high as 30-35%. |