Claims
- 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.
- 2. A film as claimed in claim 1, wherein the external polyester layers comprise polyethylene terephthalate.
- 3. A film as claimed in claim 2, wherein the intermediate layer comprises a copolyester containing between about 5 and 95% by weight of ethylene isophthalate units.
- 4. A film as claimed in claim 1, which is embossed on one side to form a non-planar pattern.
- 5. A film as claimed in claim 1, wherein the intermediate layer comprises a copolyester containing between about 5 and 95% by weight of ethylene isophthalate units.
- 6. A film as claimed in claim 1, wherein the total film thickness is in the range from about 5 to 350 microns, with the thickness of the intermediate layer ranging from 2 to 40 microns.
- 7. A film as claimed in claim 1, wherein the first polyester composition has a melting temperature in the range of from about 240.degree. to 260.degree. C., and the second polyester composition has a melting temperature in the range of from about 190.degree. to 230.degree. C.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3248670 |
Dec 1982 |
DEX |
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Parent Case Info
This application is a continuation of Ser. No. 566,898 filed Dec. 29, 1983, now abandoned.
US Referenced Citations (8)
Foreign Referenced Citations (1)
Number |
Date |
Country |
1115713 |
May 1968 |
GBX |
Continuations (1)
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Number |
Date |
Country |
Parent |
566898 |
Dec 1983 |
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