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US 12,305,090 B2Granted
Protective films made of polyolefin support material, primer and radiation-crosslinkable hot melt adhesive
AssigneeBASF SE
InventorsDirk Wulff, Holger Kern, Matthias Gerst, Christoph Kiener
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Abstract
Described herein is a protection film comprising a polyolefin carrier material, a precoating of the polyolefin carrier material with a primer selected from polyurethane dispersions and a pressure-sensitive adhesive layer of a radiation-crosslinked hotmelt adhesive. A process for producing such protection films is also described.
Claims16
A removable protection film comprising:
- (a) a polyolefin carrier material whose surface to be coated has been pretreated, wherein the carrier material is selected from the group consisting of polyethylene and polypropylene,
- (b) a precoating of the polyolefin carrier material with at least one primer selected from aqueous polyurethane dispersions, the aqueous polyurethane dispersions consisting of a polyurethane dispersed in an aqueous solvent;
- and
- (c) a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer is formed by radiation crosslinking of a radiation-crosslinkable hotmelt adhesive and wherein the radiation-crosslinkable hotmelt adhesive comprises at least one poly(meth)acrylate formed from
- (i) at least 60% by weight of C4-to C10-alkyl (meth)acrylates and
- (ii) at least one ethylenically unsaturated monomer which comprises at least one polar group, wherein the polar group is selected from the group consisting of carboxylic acid groups, carboxylic anhydride groups, hydroxyl groups, amide groups, urethane groups, urea groups, piperidinyl groups, piperazinyl groups, morpholinyl groups, imidazoyl groups, ureido groups, pyrrolidone groups and combinations of two or more of the recited groups;
- wherein the at least one poly(meth)acrylate of the radiation-crosslinkable hotmelt adhesive has a K value of at least 30, and wherein before crosslinking the at least one poly(meth)acrylate has a glass transition temperature of not more than 10° C.,
- and wherein the radiation-crosslinkable hotmelt adhesive includes at least one photoinitiator and the photoinitiator is in the form of an additive not bonded to the at least one poly(meth)acrylate and/or the photoinitiator is incorporated into the at least one poly(meth)acrylate by polymerization, wherein the removable protection film exhibits a force for removal of the removable protection film from brushed steel of not more than 5 N/25 mm at 23° C.
5 more elements
A process for producing protection films, comprising:
- (1) precoating a polyolefin carrier material whose surface to be coated has been pretreated with at least one primer, wherein the at least one primer is selected from polyurethane dispersions, the aqueous polyurethane dispersions consisting of a polyurethane dispersed in an aqueous solvent, thereby forming a primer layer;
- and
- (2) applying a pressure-sensitive adhesive layer to the primer layer, wherein the pressure-sensitive adhesive layer is formed by radiation crosslinking of a radiation-crosslinkable hotmelt adhesive and wherein the radiation-crosslinkable hotmelt adhesive comprises at least one poly(meth)acrylate, wherein before crosslinking the at least one radiation-crosslinkable poly(meth)acrylate has a glass transition temperature of not more than 10° C., formed from
- (i) at least 50% by weight of C1-to C18-alkyl (meth)acrylates and
- (ii) at least one ethylenically unsaturated monomer which comprises at least one polar group, wherein the polar group is selected from the group consisting of carboxylic acid groups, carboxylic anhydride groups, hydroxyl groups, amide groups, urethane groups, urea groups, piperidinyl groups, piperazinyl groups, morpholinyl groups, imidazoyl groups, ureido groups, pyrrolidone groups and combinations of two or more of the recited groups;
- and wherein the radiation-crosslinkable hotmelt adhesive includes at least one photoinitiator and the photoinitiator is in the form of an additive not bonded to the at least one poly(meth)acrylate and/or the photoinitiator is incorporated into the at least one poly(meth)acrylate by polymerization.
3 more elements
Dependencies are inferred from the claim text.