White polyester film with properties of lightweight and low-shrinkage

摘要

A white polyester film with a specific weight of 0.6-1.2 has a three-layered structure containing two outer layers (A) having a combined thickness taking up 2% to 30% of an overall thickness of the film and a middle layer (B), and having air-bubble cells in both the outer layers (A) and the middle layer (B). The outer layers (A) are formed from a polyester resin and inorganic particles. The middle layer (B) is formed of a polyester resin, modified polypropylene resin having a heat distortion temperature above 120° C. and a melt flow index (MI) of 0.2-1 g/10 minutes (at 230° C., with a load of 2.16 kg) via crosslinking with 0.1-3 wt % of peroxide with respect to the weight of the polypropylene resin, and inorganic particles.