Graft composition having long chain branched olefins for improved layers
A tie layer adhesive composition for multilayer structures made up of graft composition compounded with a base resin, such as linear low density polyethylene (LLDPE), and a polyethylene having long chain branching, such as low density polyethylene (LDPE), and optionally one or more additives. The graft composition can be made up of a blend of a grafted polyolefin and an olefin elastomer and/or the reaction product of a live, grafted polyolefin and an olefin elastomer.
1. A composition comprising:
A) from 1 to 30 percent by weight of a grafted polyolefin copolymer comprising:
(i) a grafted polyolefin
(ii) an olefin elastomer
wherein the grafted polyolefin is chemically bonded to the olefin elastomer, and wherein the olefin elastomer is present in the range of 5 to 60 wt % of the grafted polyolefin copolymer;
B) from 65 to 85 percent by weight of a linear polyethylene;
C) from 0.5 to 25 percent by weight of a polyethylene having long chain branching; and
D) optionally one or more additives.
2. The composition of claim 1 wherein the grafted polyolefin or the live grafted polyolefin is high-density polyethylene (HDPE) grafted with maleic anhydride.
3. The composition of claim 1 wherein the olefin elastomer is ethylene-propylene rubber (EPR) or ethylene-propylene-diene monomer rubber (EPDM).
4. The composition of claim 1 , wherein component A) contains from 5 to 30 percent by weight of at least one grafted polyolefin copolymer.
5. The composition of claim 1 , wherein the linear polyethylene in component B) is a linear low density polyethylene (LLDPE).
6. The composition of claim 1 , wherein the branched polyethylene in component C) is a low density polyethylene (LDPE).
7. The composition of claim 1 , wherein component D) is present and the one or more additives are selected from the group consisting of antioxidants, stabilizers, and combinations thereof.
8. The composition of claim 1 wherein the composition is a tie layer adhesive.
9. A multi-layered film comprising a tie-layer adhesive consisting of
A) from 1 to 30 percent by weight of a grafted polyolefin copolymer comprising:
(i) a grafted polyolefin
(ii) an olefin elastomer
wherein the grafted polyolefin is chemically bonded to the olefin elastomer, and wherein the olefin elastomer is present in the range of 5 to 60 wt % of the grafted polyolefin copolymer;
B) from 65 to 85 percent by weight of a linear polyethylene;
C) from 0.5 to 25 percent by weight of a polyethylene having long chain branching; and
D) optionally one or more additives.
10. The multi-layered film of claim 9 , wherein components A), B), C), and optionally D) are dry blended and melt extruded to form the tie-layer adhesive.
11. The multi-layered film of claim 9 , wherein the multi-layered film comprises a layer of polyolefin and a layer comprising a polar polymer.
12. The multilayer film of 11 , wherein the polar polymer is ethylene vinyl alcohol copolymer (EVOH) or a polyamide.
13. A process for producing a tie-layer adhesive comprising:
reacting a grafted polyolefin with an olefin elastomer to produce a grafted polyolefin composition;
compounding
from 1 to 30 percent by weight of said grafted polyolefin composition,
from 65 to 85 percent by weight of a linear polyethylene,
from 0.5 to 25 percent by weight of a polyethylene having long chain branching, and optionally one or more additives to form a tie-layer adhesive.
14. The process of claim 13 wherein the grafted polyolefin is high-density polyethylene (HDPE) grafted with maleic anhydride.
15. The process of claim 13 wherein the olefin elastomer is ethylene-propylene rubber (EPR) or ethylene-propylene-diene monomer rubber (EPDM).