Patent ID: 7022408

Claim:
A pressure sensitive adhesive, oriented and crosslinked in the oriented state, comprising a polymer at least 65% of which is made up of at least one acrylic monomer selected from the group consisting of monomers of the following formula: where R 1 =H or CH 3 and the radical R 2 =H or CH 3 or is selected from the group consisting of branched or unbranched saturated alkyl groups having 2–20 carbon atoms, the weight average molecular weight (M w ) of the polymer is at least 650,000, the refractive index of the adhesive, measured in the oriented direction n MD is greater than the refractive index measured in a direction perpendicular to the oriented direction n CD , the difference Δn=n MD −n CD being at least 1•10 −5 .