Release coating compositions for pressure sensitive adhesive articles and methods
A method of making a release coated article is described comprising: providing a release coating composition comprising at least 50 wt. % of a mixture of ethylenically unsaturated monomers based on the total ethylenically unsaturated components; wherein the mixture comprises monomer(s) with a linear alkyl group with at least 18 carbon atoms, and monomer(s) with a branched alkyl group with 7 to 31 carbon atoms, and crosslinking component(s) comprising at least two ethylenically unsaturated groups. The method comprises applying the release coating to a major surface of a substrate and polymerizing the monomer(s) and crosslinking component(s) of the release coating. The monomer(s) with linear alkyl groups and branched alkyl groups are typically present at a weight ratio such that the release coating is a liquid at 25° C. Also described are release coating compositions and articles.
1 . A method of making a pressure sensitive adhesive article comprising:
providing a release coating composition comprising
at least 50 wt. % of a mixture of ethylenically unsaturated monomers based on the total ethylenically unsaturated components, wherein the mixture comprises
monomer(s) with a linear alkyl group with at least 18 carbon atoms, and
monomer(s) with a branched alkyl group with 7 to 31 carbon atoms;
crosslinking component(s) comprising at least two ethylenically unsaturated groups and wherein the crosslinking component(s) lacks polydiorganosiloxane moieties; and
a polymerization initiator;
wherein the release coating composition comprises no greater than 1 wt. % of non-polymerizable organic solvent;
applying the release coating to a major surface of a substrate;
polymerizing the monomer(s) and crosslinking component(s) of the release coating after applying the release coating to the substrate; and
contacting a pressure sensitive adhesive to the release coating.
2 . The method of claim 1 wherein the polymerization initiator is a free-radical initiator.
3 . The method of claim 2 wherein the free-radical initiator is a photoinitiator.
4 . The method of claim 1 wherein the monomer(s) with linear alkyl group and branched alkyl group are present at a weight ratio such that the release coating is a liquid at 25° C.
5 . The method of claim 1 wherein the monomer(s) with a linear alkyl group and the monomer(s) with a branched alkyl group are present at a weight ratio less than 80:20, 75:25, 70:30, 65:35, 60:40, or 55:45.
6 . The method of claim 1 wherein the monomer(s) with a linear alkyl group and the monomer(s) with a branched alkyl group are present at a weight ratio less than 50:50, 45:55, 40:60, 35:65, or 30:70.
7 . The method of claim 1 wherein the monomer(s) with a branched alkyl groups comprises
8 . The method of claim 1 wherein the momomer(s) with a branched alkyl group have the formula
wherein:
R 1 and R 2 are each independently a C 1 to C 30 saturated linear alkyl group;
the sum of the number of carbons in R 1 and R 2 is 7 to 31; and
R 3 is H or CH 3 .
9 . The method of claim 8 wherein the sum of the number of carbons in R 1 and R 2 is 7 to 17.
10 . The method of claim 1 wherein the momomer(s) with a branched alkyl group comprise at least three structural isomers of alkyl (meth)acrylate of the formula:
wherein:
R 1 and R 2 are each independently a C 1 to C 30 saturated linear alkyl group;
the sum of the number of carbons in R 1 and R 2 is 7 to 31; and
R 3 is H or CH 3 .
11 . The method of claim 1 wherein the crosslinking component(s) comprises at least 3, 4, 5, or 6 ethylenically unsaturated groups.
12 . The method of claim 1 wherein the crosslinking component(s) is not an aliphatic urethane (meth)acrylate.
13 . The method of claim 1 wherein the ethylenically unsaturated groups are free-radically polymerizable groups.
14 . The method of claim 13 wherein the free-radically polymerizable groups are (meth)acrylate groups.
15 . The method of claim 1 wherein the substrate is selected from an organic polymeric film, metal coated film, metallic foil, paper, or fibrous web.
16 . A pressure sensitive adhesive article comprising:
a substrate;
a release coating composition disposed on a major surface of the substrate, wherein the release coating comprises polymerized units of at least 50 wt. % of a mixture of ethylenically unsaturated monomers based on the total ethylenically unsaturated components, wherein the mixture comprises
monomer(s) with a linear alkyl group with at least 18 carbon atoms; and
monomer(s) with a branched alkyl group with 7 to 31 carbon atoms;
crosslinking component(s) comprising at least two ethylenically unsaturated groups and wherein the crosslinking component(s) lacks polydiorganosiloxane moieties; and
a pressure sensitive adhesive layer in contact with the release coating.
17 . The pressure sensitive adhesive article of claim 16 wherein the pressure sensitive adhesive comprises at least one polymer selected from an acrylic copolymer, natural rubber, synthetic rubber, or a silicone polymer.
18 . The pressure sensitive adhesive article of claim 16 wherein the monomer(s) with a linear alkyl group and the monomer(s) with a branched alkyl group are present at a weight ratio less than 80:20, 75:25, 70:30, 65:35, 60:40, or 55:45.
19 . The pressure sensitive adhesive article of claim 16 wherein the monomer(s) with a linear alkyl group and the monomer(s) with a branched alkyl group are present at a weight ratio less than 50:50, 45:55, 40:60, 35:65, or 30:70.
20 . The method pressure sensitive adhesive article of claim 16 wherein the momomer(s) with a branched alkyl group comprise at least three structural isomers of alkyl (meth)acrylate of the formula:
wherein:
R 1 and R 2 are each independently a C 1 to C 30 saturated linear alkyl group;
the sum of the number of carbons in R 1 and R 2 is 7 to 31; and
R 3 is H or CH 3 .