Pressure-sensitive adhesives with mixed photocrosslinking system
The present disclosure provides a method of providing an adhesive composition comprising the steps of combining crosslinkable composition including: a) a (meth)acryloyl monomer mixture with the b) photocrosslinking agent mixture, and irradiating with UVC radiation to polymerize and crosslink the composition.
1. A crosslinkable syrup composition comprising:
a) solute copolymer comprising interpolymerized monomer units of:
i) a (meth)acrylic acid ester monomer;
ii) an acid-functional ethylenically unsaturated monomer;
iii) an optional non-acid-functional polar monomer;
iv) an optional vinyl monomer;
b) a photocrosslinking agent mixture comprising a benzophenone photocrosslinker, and an anthraquinone photocrosslinker and/or a thioxanthone photocrosslinker; and
c) a component including at least one free-radically polymerizable solvent monomer.
2. The crosslinkable syrup composition of claim 1 wherein the photocrosslinking mixture comprises
1) 5 to 50 wt. % benzophenone photocrosslinker, and
2) 50 to 95 wt. % of either an anthraquinone photocrosslinker or a thioxanthone photocrosslinkers.
3. The crosslinkable syrup composition of claim 1 wherein the photocrosslinking mixture comprises
1) 20 to 50 wt. % benzophenone photocrosslinker, and
2) 50 to 80 wt. % of either an anthraquinone photocrosslinker or a thioxanthone photocrosslinkers.
4. The crosslinkable syrup composition of claim 1 comprising 0.01 to 10 wt % of the photocrosslinking mixture relative to the solvent monomer component.
5. The crosslinkable syrup composition of claim 1 comprising 0.1 to 5 wt % of the photocrosslinking mixture relative to the solvent monomer component.
6. The crosslinkable syrup composition of claim 1 wherein the photocrosslinking mixture comprises a benzophenone photocrosslinker, and an anthraquinone photocrosslinker.
7. The crosslinkable syrup composition of claim 1 wherein the photocrosslinking mixture comprises a benzophenone photocrosslinker and a thioxanthone photocrosslinker.
8. The crosslinkable syrup composition of claim 1 wherein the photocrosslinking mixture comprises a benzophenone photocrosslinker, a thioxanthone photocrosslinker, and an anthraquinone photocrosslinker.
9. The crosslinkable syrup composition of claim 1 wherein the solvent monomer component comprises:
i. 85 to 99.5 parts by weight of an (meth)acrylic acid ester of non-tertiary alcohol;
ii. 0.5 to 15 parts by weight of an acid functional ethylenically unsaturated monomer;
iii. 0 to 10 parts by weight of a non-acid functional, ethylenically unsaturated polar monomer;
iv. 0 to 5 parts vinyl monomer; and
v. 0 to 5 parts of a multifunctional (meth)acrylate;
based on 100 parts by weight total monomer.
10. The crosslinkable syrup composition of claim 1 wherein the solvent monomer component comprises 0.01 to 5 parts of the multifunctional (meth)acrylate, based on 100 parts total monomers.
11. The crosslinkable syrup composition of claim 10 further comprising a chain transfer agent.
12. An adhesive composition comprising a (meth)acryloyl copolymer comprising:
a) an acid-functional (meth)acryloyl copolymer of interpolymerized monomers that include:
i) a (meth)acrylic acid ester;
ii) an acid-functional ethylenically unsaturated monomer;
iii) an optional non-acid-functional polar monomer;
iv) an optional vinyl monomer; and
v) an optional multifunctional (meth)acrylate crosslinker, and
b) the residues of a benzophenone photocrosslinker, and an anthraquinone photocrosslinker and/or a thioxanthone photocrosslinker in the copolymer matrix.