Universal thermoplastic adhesives for multilayer films
Embodiments of the present disclosure are directed to a thermoplastic adhesive composition comprising: at least one maleic anhydride-grafted ethylene-based polymer; at least one at least one ethylene/α-olefin/non-conjugated diene interpolymer having a molecular weight distribution (MWD) ≥2.5, wherein MWD=Mw/Mn, wherein Mw is weight averaged molecular weight and Mn is number averaged molecular weight, which are both determined by gel permeation chromatography; a very low density polyethylene (VLDPE) having a density in the range 0.885 to 0.915 grams/cm 3 ; and optionally at least one ethylene alkyl (meth)acrylate copolymer, wherein the alkyl group comprises one to four carbon atoms.
1. A thermoplastic adhesive composition comprising:
at least one maleic anhydride-grafted ethylene-based polymer;
at least one ethylene/α-olefin/non-conjugated diene interpolymer having a molecular weight distribution (MWD) ≥2.5, wherein MWD=Mw/Mn, wherein Mw is weight averaged molecular weight and Mn is number averaged molecular weight, which are both determined by gel permeation chromatography;
a very low density polyethylene (VLDPE) having a density in the range 0.885 to 0.915 grams/cm 3 .
2. The thermoplastic adhesive composition of claim 1 , further comprising at least one ethylene alkyl (meth)acrylate copolymer, wherein the alkyl group comprises one to four carbon atoms.
3. The thermoplastic adhesive composition of claim 2 , wherein the ethylene alkyl (meth)acrylate copolymer comprises a density of 0.930 to 0.960 g/cc.
4. The thermoplastic adhesive composition of claim 2 , wherein the thermoplastic adhesive composition comprises from 20 to 40% by weight of ethylene alkyl (meth)acrylate copolymer.
5. The thermoplastic adhesive composition of claim 1 , wherein the maleic anhydride-grafted ethylene-based polymer comprises one or more of a maleic anhydride grafted linear low density polyethylene, a maleic anhydride grafted polyethylene elastomer, or a combination thereof.
6. The thermoplastic adhesive composition of claim 1 , wherein the maleic anhydride-grafted ethylene-based polymer has a density below 0.900 g/cc and a melt index (12) between 1 to 20 g/10 min.
7. The thermoplastic adhesive composition of claim 1 , wherein the thermoplastic adhesive composition comprises from 10 to 40% by weight of maleic anhydride-grafted ethylene-based polymer.
8. The thermoplastic adhesive composition of claim 1 , wherein the α-olefin of the ethylene/α-olefin/non-conjugated diene interpolymer is propylene and the non-conjugated diene of the ethylene/α-olefin/non-conjugated diene interpolymer is ethylidene-norbornene.
9. The thermoplastic adhesive composition of claim 1 , wherein the thermoplastic adhesive composition comprises from 15 to 35% by weight of ethylene/α-olefin/non-conjugated diene interpolymer.
10. The thermoplastic adhesive composition of claim 1 , wherein the VLDPE has a melt index (12) from 2 to 8 g/10 mins.
11. The thermoplastic adhesive composition of claim 1 , wherein the thermoplastic adhesive composition comprises from 15 to 50% by weight of the VLDPE.
12. The thermoplastic adhesive composition of claim 1 , wherein the ethylene/α-olefin/non-conjugated diene interpolymer has a crystallinity from 7 to 20% as determined by Differential Scanning Calorimetry.