Claims
- 1. A multilayer film comprising skin layers A wherein the skin layers A essentially consist of a polyolefin selected from:A1) a composition containing i) 25-45% by weight of a random copolymer of propylene and ethylene having 2-5% by weight of ethylene units; and ii) 55-75% by weight of a random terpolymer of propylene, ethylene and one or more C4-C10 alphaolefins having 2-5% by weight of ethylene units and 6-12% by weight of alphaolefin units; or A2) a random copolymer of propylene and one or more C4-C10 alphaolefins or a blend of random copolymers of propylene and one or more C4-C10 alphaolefins with different composition, said copolymer or blend of copolymers containing 4-14% by weight of alphaolefin units; said polyolefin having a xylene-insoluble fraction greater than 85% by weight, a maximum melting peak at temperatures above 130° C. and a crystallinity such that at 90° C. the percentage of material melted is greater than 15% by weight; and a core layer B wherein the core layer B essentially consists of a heterophasic composition comprising: a) 20-60% by weight of a propylene homopolymer with an isotacticity index value, determined as percent by weight of the polymer insoluble in xylene at 25° C., higher than 80 or of a propylene crystalline copolymer with ethylene and/or C4-C10 alphaolefins containing at least 85% by weight of propylene units and having an isotacticity index value of at least 80 or of mixtures thereof; and b) 40-80% by weight of an ethylene copolymer with propylene and/or 1-butene and optionally a diene, containing 20-60% by weight of ethylene units and completely soluble in xylene at 25° C.
- 2. The multilayer film according to claim 1 wherein the polyolefin forming the skin layers A consists of the composition A1 containing 30-40% by weight of a random copolymer of propylene and ethylene having 3-4% by weight of ethylene units and 60-70% by weight of a random terpolymer of propylene, ethylene and one or more C4-C10 alphaolefins having 3-4% by weight of ethylene units and 8-10% by weight of alphaolefin units.
- 3. The multilayer film according to claim 1 wherein the alphaolefin present in the random terpolymer of composition A1 is 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, or 1-octene.
- 4. The multilayer film according to claim 1 wherein the alphaolefin present in the random terpolymer of composition A1 is 1-butene.
- 5. The multilayer film according to claim 1 wherein the polyolefin forming the skin layers A consists of a random copolymer of propylene and 1-butene with a content of 4-10% by weight of 1-butene units.
- 6. The multilayer film according to claim 1 wherein the polyolefin forming layers A consists of a blend of random copolymers of propylene and 1-butene having a different content of 1-butene units.
- 7. The multilayer film according to claim 1 wherein the heterophasic composition forming layer B consists of:a) 25-45% by weight of a propylene homopolymer with an isotacticity index value, determined as percent by weight of the polymer insoluble in xylene at 25° C., higher than 80 or of a propylene crystalline copolymer with ethylene and/or C4-C10 alphaolefins containing at least 85% by weight of propylene units and having an isotacticity index value of at least 80, or of mixtures thereof and b) 55-75% by weight of an ethylene copolymer with propylene and/or 1-butene and 0-10% by weight of a diene, containing 20-60% by weight of ethylene units and completely soluble in xylene at 25° C.
- 8. The multilayer film according to claim 1 wherein the alphaolefin present in fraction a) of the heterophasic composition of layer B is 1-butene, 1-hexene, 4-methyl-1-pentene or 1-octene.
- 9. The multilayer film according to claim 1 wherein the alphaolefin is 1-butene in each and every occurrence.
- 10. The multilayer film according to claim 1 wherein the diene optionally present in fraction b) of layer B is 1,3-butadiene, 1,4-hexadiene or 5-ethylidene -2-norbomene.
- 11. The multilayer film according to claim 1 wherein the heterophasic composition forming layer B consists of:a) 30-40% by weight of a propylene crystalline copolymer with ethylene containing at least 90% by weight of propylene units; and b) 60-70% by weight of an ethylene copolymer with propylene containing 25-60% by weight of ethylene units and completely soluble in xylene at 25° C.
- 12. The multilayer film according to claim 1 wherein the heterophasic composition forming layer B is partly crosslinked.
- 13. The multilayer film according to claim 1 wherein the heterophasic composition forming layer B has a melt flow rate according to ASTM D 1238 condition L in the range from 0.4 to 3 g/10 minutes.
- 14. The multilayer film according to claim 1 wherein the heterophasic composition forming layer B has a melt flow rate according to ASTM D 1238 condition L in the range from 0.5 to 1.5 g/10 minutes.
- 15. The multilayer film according to claim 1 wherein the polymer composition of layer B further comprises up to 75% by weight, referred to the total weight of layer B, of a component essentially the same as the polymer forming layer A but with a melt flow rate, according to ASTM D 1238 condition L, in the range 0.5-1 g/10 minutes.
- 16. A three-layer film ABA according to claim 1 wherein each of the skin layers A is present in amounts from 5 to 45% of the total weight of the film.
- 17. A three-layer film ABA according to claim 1 wherein the skin layers A are present in equal amounts, each in the range from 10 to 30% of the total weight of the film.
- 18. A multilayer packaging film according to claim 1.
Priority Claims (1)
Number |
Date |
Country |
Kind |
00201022 |
Mar 2000 |
EP |
|
Parent Case Info
This application is the U.S. national phase of International Application PCT/EP01/02858, filed Mar. 14, 2001.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/EP01/02858 |
|
WO |
00 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO01/70500 |
9/27/2001 |
WO |
A |
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A |
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