Multilayer film formed of polyester and having a core layer suitable for thermoplastic embossing

Claim 1

An embossable, biaxially stretched and heat-set multilayer film, comprising: two external layers comprised of a first polyester composition and, sandwiched between said external layers, a core layer comprised of a second polyester composition having a lower-melting temperature than said first polyester composition, whereby the film can be embossed at higher temperatures and substantially maintains the resulting depth of embossing in a thermal treatment which is necessary for the further processing of the film after embossing with the following provisos: (i) that said multilayer film possess an asymmetric structure wherein said core layer is thicker than at least one of said external layers; (ii) that said core layer thickness is from 1 to 100 microns; (iii) that one of said external layers has a thickness which may range from 0.1 to 10 microns; (iv) that the other external layer has a thickness which may range from 1 to 100 microns.