Propylene elastomer-containing adhesive blends
View Patent ↗Adhesive blends suitable for use as tie-layer adhesives for a variety of substrates used in multi-layer film and sheet constructions are provided. The adhesive blends contain a polyolefin base resin, a functionalized polyolefin and a propylene elastomer containing isotactic propylene crystallinity.
1. An adhesive blend consisting essentially of:
(a) 25 to 85 weight percent, based on the total weight of the blend composition, polyolefin selected from the group consisting of high density polyethylene and linear low density polyethylene;
(b) 2.5 to 25 weight percent, based on the total weight of the blend composition, high density polyethylene or linear low density polyethylene grafted with 0.5 to 4 weight percent maleic anhydride; and
(c) 2.5 to 40 weight percent, based on the total weight of the blend composition, propylene elastomer having a propylene content of 60 mole percent or greater and isotactic propylene crystallinity, density from 0.840 to 0.890 g/cm 3 and melt flow rate from 1 to 500 g/10 min
(d) 5-25% of an ethylene alpha olefin copolymer plastomer.
2. The adhesive blend of claim 1 wherein (a) has a melt index from 0.01 to 400 g/10 min.
3. The adhesive blend of claim 2 wherein (a) is high density polyethylene having a density from 0.945 to 0.969 g/cm 3 and melt index from 0.1 to 200 g/10 min.
4. The adhesive blend of claim 2 wherein (a) is linear low density polyethylene having a density from 0.910 to 0.930 g/cm 3 and melt index from 0.1 to 200 g/10 min.
5. The adhesive blend of claim 2 wherein (c) contains 70 mole percent or greater propylene, has a density from 0.850 to 0.875 g/cm 3 and melt flow rate from 2 to 100 g/10 min.
6. The adhesive blend of claim 2 comprised of 40 to 80 weight percent (a), 4 to 20 weight percent (b) and 4 to 30 weight percent (c).
7. An adhesive blend consisting essentially of:
(a) 60 to 80 weight percent, based on the total weight of the blend composition, high density polyethylene,
(b) 5 to 15 weight percent, based on the total weight of the blend composition, high density polyethylene grafted with 1 to 4 weight percent maleic anhydride, and
(c) 5 to 25 weight percent, based on the total weight of the blend composition, propylene elastomer having a propylene content of 70 mole percent or greater and isotactic propylene crystallinity, density from 0.850 to 0.875 g/cm 3 and melt flow rate from 2 to 20 g/10 min; said adhesive blend having a melt index from 2 to 20 g/10 min.
8. The adhesive blend of claim 7 which additionally contains 5 to 25 weight percent ethylene-C 4-8 α-olefin copolymer plastomer.
9. A multi-layer film or sheet comprising a styrene layer and a tie-layer adhesively bonded thereto, said tie-layer comprising an adhesive blend consisting essentially of:
a) 25 to 85 weight percent, based on the total weight of the blend composition, polyolefin selected from the group consisting of high density polyethylene and linear low density polyethylene;
(b) 2.5 to 25 weight percent, based on the total weight of the blend composition, high density polyethylene or linear low density polyethylene grafted with 0.5 to 4 weight percent maleic anhydride and;
(c) 2.5 to 40 weight percent, based on the total weight of the blend composition, propylene elastomer having a propylene content of 60 mole percent or greater and isotactic propylene crystallinity, density from 0.840 to 0.890 g/cm 3 and melt flow rate from 1 to 500 g/10 min.
10. The multi-layer film or sheet of claim 9 further comprising a second polymer layer and wherein said tie-layer is disposed between the styrene layer and the second polymer layers.
11. The multi-layer film or sheet of claim 10 wherein the second polymer layer is a barrier resin layer.
12. A multi-layer film or sheet comprising a metal layer and a tie-layer adhesively bonded thereto, said tie-layer comprising an adhesive blend consisting essentially of:
a) 25 to 85 weight percent, based on the total weight of the blend composition, polyolefin selected from the group consisting of high density polyethylene and linear low density polyethylene;
(b) 2.5 to 25 weight percent, based on the total weight of the blend composition, high density polyethylene or linear low density polyethylene grafted with 0.5 to 4 weight percent maleic anhydride; and
(c) 2.5 to 40 weight percent, based on the total weight of the blend composition, propylene elastomer having a propylene content of 60 mole percent or greater and isotactic propylene crystallinity, density from 0.840 to 0.890 g/cm 3 and melt flow rate from 1 to 500 g/10 min.
13. The multi-layer film or sheet of claim 10 wherein the second polymer layer is a polyolefin layer.
14. The multi-layer film or sheet of claim 12 further comprising a polymer layer and wherein said tie-layer is disposed between the metal layer and the polymer layer.
15. The multi-layer film or sheet of claim 14 wherein the polymer layer is a polyolefin selected from the group consisting of high density polyethylene and linear low density polyethylene.