Pressure sensitive adhesive composition which is repulpable under acidic pH conditions

Claim 1

A pressure sensitive adhesive composition comprising (a) a terpolymer formed from A, B and C monomers wherein, A is a hydrophobic monomer selected from the group consisting of acrylic or a methacrylic ester of a non-tertiary alcohol, the alcohol having 2 to 14 carbon atoms, wherein A comprises from 30 to 85% by total weight of the A plus B plus C; B is a polar monomer copolymerizable with said A monomer and having hydroxyl, carboxyl, sulfonic acid functionality or combinations thereof, with the proviso that if B contains the hydroxyl functionality it is combined with a monomer having an acid group, wherein B comprises from 2 to 50% by total weight of A plus B plus C, and wherein from 5 to 100% of any said acidic group has been neutralized; and C is a water-dispersible macromolecular monomer which is copolymerizable with A and B and has the formula X--Y--Z wherein X is a structural element comprising a moiety which is copolymerizable with A and B, Y is a divalent linking group joining X to Z, and Z is a water-dispersible moiety containing at least two units which are essentially unreactive under free radical initiated copolymerization conditions used to form the terpolymer, wherein C comprises from 10 to 50% by total weight of A plus B plus C; and (b) an additive selected from the group consisting of tackifiers, plasticizers, and combinations thereof wherein the ratio of said additive to said terpolymer is in the range of from 0.2:1 to 5:1 wherein said composition is repulpable at a pH of from 2 to 11.