Granted Patent B2

US 7,611,768 · App. 11/941,425 · Granted Nov 3, 2009

Abstract

Claims (33)

1. A multilayer stretch film comprising:

a slip layer comprising at least polypropylene and high-density polyethylene blend;

a cling layer comprising at least a styrene block copolymer material; and

an intermediary layer comprising at least linear low-density polyethylene resin or its blend;

wherein the cling layer comprises 60-100% styrene block copolymer material.

2. The multilayer stretch film of claim 1 , wherein the intermediary layer further comprises titanium dioxide.

3. The multilayer stretch film of claim 1 , wherein the slip layer comprises about 3% to about 20% by weight, the cling layer comprises about 5% to about 20% by weight, and the intermediary layer comprises about 60% to about 90% by weight.

4. The multilayer stretch film of claim 3 , the slip layer comprises about 15% by weight, the cling layer comprises about 5% by weight, and the intermediary layer comprises about 80% by weight.

5. The multilayer stretch film of claim 1 , wherein the slip layer has a coefficient of friction between about 0.3 to about 0.9, and wherein the cling layer has a cling force to the slip layer between about 5 g/in to about 80 g/in.

6. The multilayer stretch film of claim 5 , wherein the slip layer has a coefficient of friction of about 0.5, and wherein the cling layer has a cling force to the slip layer of about 50 g/in.

7. The multilayer stretch film of claim 1 , wherein the slip layer comprises between about 70% and about 99% by weight polypropylene and between about 1% to about 30% by weight high-density polyethylene.

8. The multilayer stretch film of claim 7 , wherein slip layer comprises about 80% by weight polypropylene and about 20% by weight high-density polyethylene.

9. The multilayer stretch film of claim 1 , wherein the intermediary layer comprises between about 50% and 100% by weight linear low-density polyethylene.

10. The multilayer stretch film of claim 9 , wherein the intermediary layer further comprises between about 0.1% to about 5% by weight titanium dioxide.

11. The multilayer stretch film of claim 10 , wherein the intermediary layer comprises about 98% by weight linear low-density polyethylene and about 2% by weight titanium dioxide.

12. The multilayer stretch film of claim 1 , wherein the multilayer film can withstand a force stretch of the film to about 400% at about 5000 psi.

13. The multilayer stretch film of claim 1 , wherein the overall multilayer film thickness is between about 0.012 mm to about 0.125 mm.

14. The multilayer stretch film of claim 13 , wherein the overall multilayer film thickness is about 0.025 mm.

15. The multilayer stretch film of claim 1 , wherein the intermediary layer comprises at least two individual layers.

16. The multilayer stretch film of claim 15 , wherein the at least two individual layers each comprise a material selected from the group consisting of Linear Low-Density Polyethylene, metallocene-catalyzed Low-Density Polyethylene, Low-Density Polyethylene, Mid-Density Polyethylene, High-Density Polyethylene, Polypropylene, and any homopolymers, copolymers or blend thereof.

17. A multilayer stretch film comprising:

a first surface layer having a coefficient of friction at least less than about 0.9, comprising at least polypropylene and high-density polyethylene;

a second surface layer having a cling force to the first surface layer at least greater than about 5 g/in, comprising at least a styrenic block copolymer; and

a core layer, positioned between the first surface layer and the second surface layer, comprising at least linear low-density polyethylene resin;

wherein the second surface layer comprises 60-100% styrene block copolymer material.

18. The multilayer stretch film of claim 17 , wherein the coefficient of friction of the first surface layer is about 0.5, and wherein the cling force of the second surface layer to the first surface layer is about 50 g/in.

19. The multilayer stretch film of claim 17 , wherein the first surface layer comprises about 5% to about 20% by weight, the second surface layer comprises about 3% to about 20% by weight, and the core layer comprises about 60% to about 90% by weight.

20. The multilayer stretch film of claim 17 , wherein the first surface layer comprises about 15% by weight, the second surface layer comprises about 5% by weight, and the core layer comprises about 80% by weight.

21. The multilayer stretch film of claim 17 , wherein the first surface layer comprises between about 75% and about 99% by weight polypropylene and between about 1% to about 25% by weight high-density polyethylene.

22. The multilayer stretch film of claim 21 , wherein first surface layer comprises about 80% by weight polypropylene and about 20% by weight high-density polyethylene.

23. The multilayer stretch film of claim 17 , wherein the second surface layer comprises between about 80% and 100% by weight of a styrene block copolymer.

24. The multilayer stretch film of claim 17 , wherein the core layer comprises between about 50% and 100% by weight linear low-density polyethylene.

25. The multilayer stretch film of claim 24 , wherein the core layer further comprises between about 0.1% to about 5% by weight titanium dioxide.

Assignments (35)