Adhesive compositions
View Patent ↗Adhesive compositions suitable for use as tie-layer adhesives in multi-layer films and sheets are provided. The adhesive compositions contain an olefin polymer base resin, a modified polyolefin and a paraffinic liquid hydrocarbon.
1. An adhesive composition comprising:
(a) 2 to 30 wt. % of a modified polyolefin comprising a polymer grafted with carboxylic acids, carboxylic acid anhydrides or derivatives thereof, the polymer being selected from a group consisting of (i) ethylene homopolymers, (ii) copolymers of ethylene with propylene, 1-butene, 4-methyl 1-pentene, 1-hexene, or 1-octene, (iii) propylene homopolymers, (iv) copolymers of propylene with ethylene or C 4 -C 10 α-olefins, and (v) mixtures of (i)-(iv);
(b) 0.02 to 0.3 wt. % of a polyalphaolefin polymer; and
(c) 65 to 98 wt. % of an olefin polymer base resin.
2. The adhesive composition of claim 1 wherein the olefin polymer base resin is selected from a group consisting of (i) a propylene homopolymer, (ii) a copolymer of propylene with up to about 30 wt. % of a comonomer selected from ethylene or C 4-8 α-olefins, (iii) an ethylene homopolymer, (iv) an ethylene copolymer with a comonomer selected from propylene, C 4-8 α-olefins, vinyl carboxylates, acrylic and methacrylic acids and esters, and (v) mixtures of (i)-(iv).
3. The adhesive composition of claim 1 wherein the modified polyolefin is present in an amount from 4 to 25 wt. %.
4. The adhesive composition of claim 1 wherein the modified polyolefin is present in an amount from 7 to 15 wt. %.
5. The adhesive composition of claim 1 wherein the polyalphaolefin polymer is one or more polyalphaolefin polymers.
6. The adhesive composition of claim 1 wherein the olefin polymer base resin has a crystallinity greater than 30 wt. %.
7. The adhesive composition of claim 1 wherein the olefin polymer base resin has a crystallinity greater than 40 wt %.
8. The adhesive composition of claim 1 wherein the olefin polymer base resin has a melt flow rate within a range between 0.01 and 400 dg/min.
9. The adhesive composition of claim 1 wherein the olefin polymer base resin has a melt flow rate within a range between 1 and 100 dg/min.
10. The adhesive composition of claim 1 wherein the polyalphaolefin polymer has a viscosity within a range between 85 and 1600 cSt.
11. The adhesive composition of claim 1 wherein the polyalphaolefin has a viscosity within a range between 375 and 1600 cSt.
12. The adhesive composition of claim 1 wherein the polyalphaolefin polymer has a flash point within a range between 225and 310° C.
13. The adhesive composition of claim 1 wherein the polyalphaolefin polymer has a flash point within a range between 260 and 300° C.
14. The adhesive composition of claim 1 wherein the polyalphaolefin polymer has a molecular weight within a range between 2000 and 3200.
15. The adhesive composition of claim 1 wherein the polyalphaolefin polymer has a specific gravity within a range between 0.840 and 0.860 g/cm 3 .
16. The adhesive composition of claim 1 , further comprising one or more additives comprising stabilizers, UV absorbers, metal deactivators, thiosynergists, peroxide scavengers, basic co-stabilizers, acid scavengers, nucleating agents, clarifiers, fillers, dispersing agents, plasticizers, lubricants, emulsifiers, pigments, flow-control agents, optical brighteners, flame-proofing agents, antistatic agents, and blowing agents.