High refractive index pressure-sensitive adhesives

摘要

The present invention provides pressure-sensitive adhesives having a refractive index of at least 1.50. The pressure-sensitive adhesives comprise at least one monomer containing a substituted or an unsubstituted biphenyl group.

主权项

1. An adhesive article comprising:
a flexible or inflexible substrate; and a pressure sensitive adhesive coated on the substrate, the pressure sensitive adhesive comprising: a random copolymer having:
a) 10 to 90 parts by weight of monomer units having pendent biphenyl groups;b) 90 to 10 parts by weight of alkyl (meth)acrylate monomer units;c) 1 to 15 parts by weight of acid functional monomer units;d) 0 to 15 parts by weight of polar monomers; ande) 0 to 5 parts by weight of other monomers,wherein the sum of the monomers is 100 parts by weight; and optionally a plasticizer, wherein the monomer units having pendent biphenyl groups are of the formula: wherein X1 and X2 are each independently —O—, —S—, or —NR3—, where R3 is H or C1-C4 alkyl; R1 is an alkylene of 1 to 8 carbons optionally containing one or more catenary ether oxygen atoms or pendent hydroxy groups; n is 0 or 1; and R2 is either H or CH3; such that when n is 0, the biphenyl group comprises 2-substituted biphenyl, and wherein the monomer units having pendent biphenyl groups have as homopolymers a glass transition temperature of 70° C. or less.