Ultraviolet radiation curable pressure sensitive acrylic adhesive
View Patent ↗A process for making UV curable pressure sensitive adhesive compositions by derivatizing an acrylic polymer with a derivatizing agent prepared from a hydroxy-functional acrylate monomer and a diisocyanate. The derivatizing agent typically has a ratio of hydroxy-functional acrylate monomer to diisocyanate greater than about 1:1. Also disclosed are UV curable pressure sensitive adhesives made with the derivatizing agent and methods for adhering substrates with pressure sensitive adhesive compositions.
1. A process for making an ultraviolet (“UV”) curable pressure sensitive adhesive composition comprising the step of derivatizing an acrylic polymer with about 2% to about 9% by weight solids of a derivatizing agent prepared from a hydroxy-functional acrylate monomer and a diisocyanate selected from the group consisting of isophorone diisocyanate, toluene diisocyanate and combinations thereof wherein the derivatizing agent has a ratio of hydroxy-functional acrylate monomer to diisocyanate of about 1.05:1 to about 1.5:1.
2. The process of claim 1 wherein the ratio is about 1.1:1 to about 1.2:1.
3. The process of claim 1 wherein the acrylic polymer has a molecular weight of about 40,000 to about 100,000.
4. The process of claim 1 wherein the acrylic polymer comprises a monomer selected from the group consisting of 2-ethylhexyl acrylate, iso-octyl acrylate, iso-decyl acrylate, lauryl acrylate, n-butyl acrylate and combinations thereof.
5. The process of claim 1 wherein the acrylic polymer comprises a monomer selected from the group consisting of methyl acrylate, ethyl acrylate, methyl methacrylate, styrene, vinyl acetate and combinations thereof.
6. The process of claim 1 wherein the acrylic polymer comprises at least one backbone hydroxy-functional monomer.
7. The process of claim 6 wherein the backbone hydroxy-functional monomer is selected from the group consisting of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate and combinations thereof.
8. The process of claim 1 wherein the acrylic polymer comprises a functional monomer selected from the group consisting of acrylic acid, methacrylic acid, maleic anhydride, glycidyl methacrylate, N-vinyl pyrrolidone, N-vinyl caprolactam, acrylamide and combinations thereof.
9. The process of claim 1 wherein the hydroxy-functional acrylate monomer is selected from the group consisting of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, caprolactone acrylate, and combinations thereof.