Patent ID: 8247509

Claim:
A pressure-sensitive adhesive composition used for a pressure-sensitive adhesive sheet to be directly attached to a metal surface, said composition comprising, as a main ingredient, a monomer mixture or an acrylic copolymer material obtained by at least partially polymerizing the monomer mixture, said monomer mixture comprising: at least one monomer (monomer m1) selected from alkyl(meth)acrylates represented by the following formula (I) in an amount of 50 to 99.9% by weight based on the total amount of the monomer mixture: CH 2 C(R 1 )COOR 2 (I) wherein R 1 is a hydrogen atom or a methyl group, and R 2 is an alkyl group having 1 to 20 carbon atoms, N-methylol (meth)acrylamide (monomer m2) in an amount of 0.1 to 25% by weight based on the total amount of the monomer mixture; and at least one monomer (monomer m3) selected from N-vinyl cyclic amides and (meth)acrylamides that may have an N-alkyl group, wherein the monomer m1 and the monomer m2 are contained in a total amount of 60% by weight or more based on the total amount of the monomer mixture, and monomer m3 is contained in a total amount of 40% by weight or less based on the total amount of the monomer mixture, and said monomer mixture comprises substantially no carboxyl group-containing monomer.