STRETCH FILM LAMINATION ADHESIVE
The invention provides stretch film laminant adhesives, methods of using the adhesives to bond substrates together, and to articles of manufacture comprising the adhesives. It has been discovered that a stretch film lamination adhesive, which comprises a metallocene catalyzed polyolefin copolymer with a density greater or equal to 0.870 g/cm 3 and a peak melting point greater than 100° C., a plasticizer having a number average molecular weight greater than 1,000 g/mol, and a tackifier with a softening point greater than 110° C., has high creep resistance and low plasticizer migration and bleed-through making them particularly well suited for disposable personal care garments.
1 . A stretch film lamination adhesive comprising:
a) metallocene catalyzed polyolefin copolymer which has a density greater or equal to 0.870 g/cm 3 and a peak melting point greater than 100° C.;
b) a plasticizer which has a number average molecular weight greater than 1000 g/mol; and
c) a tackifier with a softening point greater than 110° C.;
wherein the adhesive is essentially free of plasticizers with molecular weight less than 1000 g/mol.
2 . The stretch film lamination adhesive of claim 1 wherein the copolymer comprises an ethylene or propylene base comonomer.
3 . The stretch film lamination adhesive of claim 2 wherein the copolymer further comprises a C 2 -C 10 alpha olefin comonomer.
4 . The stretch film lamination adhesive of claim 3 wherein the C 2 -C 10 alpha olefin comonomer is an ethylene-octene comonomer and mixtures thereof.
5 . The stretch film lamination adhesive of claim 1 further comprising a polymer selected from the group consisting of a metallocene polyolefin, amorphous poly-α-olefin, styrene block copolymer and mixture thereof.
6 . The stretch film lamination adhesive of claim 1 wherein the plasticizer has a molecular weight greater than 1300 g/mol.
7 . The stretch film lamination adhesive of claim 6 wherein the plasticizer is a polybutene.
8 . The stretch film lamination adhesive of claim 1 wherein the tackifier has a softening point greater than 110° C.
9 . The stretch film lamination adhesive of claim 8 wherein the tackifier is selected from natural and modified rosins, synthetic hydrocarbon resins, copolymers and terpolymers of natured terpenes, including, aliphatic and aromatic petroleum hydrocarbon resins; cyclic or acyclic C 5 resins, aromatic modified acyclic and cyclic resins, or mixtures thereof
10 . The stretch film lamination adhesive of claim 9 wherein the tackifier is a hydrocarbon tackifier.
11 . A stretch film lamination adhesive comprising a metallocene catalyzed polyolefin polymer which has a density greater or equal to 0.870 g/cm 3 and a peak melting point greater than 100° C., and wherein the adhesive has a creep recovery of more than 60% at constant shear stress of 2 psi at 38° C.
12 . The stretch film lamination adhesive of claim 11 wherein the adhesive has a creep recovery of more than 80% at constant shear stress of 2 psi at 38° C.
13 . The stretch film lamination adhesive of claim 11 further comprising a plasticizer with a molecular weight greater than 1300 g/mol.
14 . The stretch film lamination adhesive of claim 11 further comprising a tackifier with a softening point greater than 110° C.
15 . An article comprising the adhesive of claim 1 .
16 . The article of claim 15 which is a diaper, diaper pad or other hygienic articles.
17 . An article comprising the adhesive of claim 11 .
18 . A multilayer film comprising the adhesive of claim 11 .
19 . The multilayer film of claim 18 wherein at least one layer of the film is selected from the group consisting of rubber, olefin, and a mixture thereof.