Polyisobutylene adhesive comprising polyolefin copolymer additive
An adhesive composition are articles are described. The adhesive composition comprises a polyisobutylene polymer component; up to 20 wt.-% of a polyolefin copolymer comprising polymerized units of an acidic monomer; and optionally, at least one tackifier. The polyolefin copolymer typically comprises C 2 -C 4 alkylene units. The polyolefin copolymer comprises polymerized units of a carboxylic acid, or unsaturated derivative thereof. In some embodiments, the polyolefin copolymer has a melting temperature ranging from 50 to 150° C. In some embodiments, the polyolefin copolymer has an acid number of less than 40, 35, 30, or 25 mgKOH/g.
1 . An adhesive composition comprising:
at least 50 wt. % of polyisobutylene polymer component, wherein the polyisobutylene polymer component comprises a first polyisobutylene polymer having a weight average molecular weight no greater than 150,000 g/mole and a second polyisobutylene polymer having a weight average molecular weight greater than to 300,000 g/mole;
wherein the first polyisobutylene polymer is in an amount equal to or greater than the second polyisobutylene polymer; optionally at least one tackifier;
optionally less than 10 wt. % of polymerized units at least one (meth)acryl monomer;
and a component that improves adhesion to metal consisting of polyolefin copolymer comprising polymerized units of C 2 -C 4 alkylenes and a carboxylic acid or an anhydride thereof, wherein the polyolefin copolymer has an acid number of less than 40 mgKOH/g and is present in an amount up to 20 wt. % of the adhesive composition; and
wherein the adhesive composition is a pressure sensitive adhesive.
2 . The adhesive composition of claim 1 wherein the polyolefin copolymer comprises at least 75 wt.-% of polymerized units of polyolefin.
3 . The adhesive composition of claim 1 wherein the polyolefin copolymer has a melting temperature ranging from 50 to 150° C.
4 . The adhesive composition of claim 1 wherein the polyolefin copolymer further comprises polymerized units of at least one (meth)acryl monomer.
5 . The adhesive composition of claim 1 wherein the polyisobutylene polymer component comprises unfunctionalized polyisobutylene polymer.
6 . The adhesive composition of claim 1 wherein the polyolefin copolymer is not covalently bonded to the polyisobutylene polymer component.
7 . The adhesive composition of claim 1 wherein the polyisobutylene polymer component has an average weight average molecular weight ranging from 150,000 to 500,000 g/mole.
8 . The adhesive composition of claim 1 , wherein the composition further contains a UV blocking agent.
9 . The adhesive composition of claim 1 , wherein the adhesive composition at a thickness of 20 microns has a haze of less than 10%.
10 . The adhesive composition of claim 1 , wherein the adhesive composition at a thickness of 20 microns has a WVTR when measured at 40° C. and a relative humidity gradient of 90% of less than 100 g/m 2 /day.
11 . The adhesive composition of claim 1 wherein the adhesive composition comprises at least 60 wt. % of the polyisobutylene polymer component.
12 . The adhesive composition of claim 1 wherein the adhesive composition exhibits a 180 degree peel to an aluminum panel of at least 1, 2, or 3 N/dm.
13 . The adhesive composition of claim 1 wherein the adhesive composition exhibits a 180 degree peel to an aluminum panel of at least 4 or 5 N/dm.
14 . The adhesive composition of claim 1 wherein the adhesive composition comprises tackifier in an amount no greater than 40 wt. %.
15 . The adhesive composition of claim 14 wherein the tackifier is a hydrogenated aliphatic hydrocarbon tackifier.
16 . An article comprising the adhesive composition of claim 1 , wherein the adhesive composition is disposed on a substrate.
17 . The article of claim 16 wherein the substrate is a release liner.
18 . The article of claim 16 , wherein the substrate is an optical film, a display unit, a touch sensor, or a lens.