Emulsion adhesive for washable film

A wash-off label comprising:

• a first polymeric layer having a first coefficient of thermal expansion;
• a second polymeric layer having a second coefficient of linear thermal expansion underlying the first polymeric layer, wherein the first coefficient of linear thermal expansion is less than the second coefficient of linear thermal expansion;
• and
• an adhesive layer underlying the second polymeric layer, the adhesive layer comprising an emulsion based pressure sensitive adhesive composition comprising an acrylic pressure sensitive adhesive copolymer of copolymerizable monomers comprising at least one ethylenically unsaturated carboxylic acid and a neutralizer, the neutralizer comprising at least one of 2-[bis-(2-hydroxyethyl)-amino]-2-hydroxymethyl propane-1,3-diol, 2-amino-2-(hydroxymethyl)-1,3-propanediol, N-methyl-D-glucamine, N,N,N′,N′-tetrakis-(2-hydroxyethyl)-ethylenediamine, and N,N,N′,N′-tetrakis-(2-hydroxypropyl)-ethylenediamine;
• and
• wherein the label is reversibly curled toward the first polymeric layer at a temperature at or above 50° C. and the adhesive is washed off upon exposure to an aqueous caustic solution at a temperature of at least 50° C.

A wash-off label comprising:

• a polymeric layer comprising at least one shrinkable film wherein the film is stretched in at least one direction;
• an adhesive layer underlying the polymeric layer, the adhesive layer comprising an emulsion based pressure sensitive adhesive composition comprising an acrylic pressure sensitive adhesive copolymer of copolymerizable monomers comprising at least one ethylenically unsaturated carboxylic acid, and a neutralizer, the neutralizer comprising at least one of 2-[bis-(2-hydroxyethyl)-amino]-2-hydroxymethyl propane-1,3-diol, 2-amino-2-(hydroxymethyl)-1,3-propanediol, N-methyl-D-glucamine, N,N,N′,N′-tetrakis-(2-hydroxyethyl)-ethylenediamine, and N,N,N′,N′-tetrakis-(2-hydroxypropyl)-ethylenediamine;
• and
• wherein the polymeric layer irreversibly shrinks at a temperature at or above 50° C. and the adhesive is washed off upon exposure to an aqueous caustic solution at a temperature of at least 50° C.

A method of detaching a label from an article, wherein the label comprises:

• a first polymeric layer having a first coefficient of linear thermal expansion;
• a second polymeric layer having a second coefficient of linear thermal expansion underlying the first polymeric layer, wherein the first coefficient of linear thermal expansion is less than the second coefficient of linear thermal expansion;
• and
• an adhesive layer underlying the second polymeric layer, the adhesive comprising an emulsion based pressure sensitive adhesive composition comprising an acrylic pressure sensitive adhesive copolymer of copolymerizable monomers comprising at least one ethylenically unsaturated carboxylic acid, and a neutralizer, the neutralizer comprising at least one of 2-[bis-(2-hydroxyethyl)-amino]-2-hydroxymethyl propane-1,3-diol, 2-amino-2-(hydroxymethyl)-1,3-propanediol, N-methyl-D-glucamine, N,N,N′,N′-tetrakis-(2-hydroxyethyl)-ethylenediamine, and N,N,N′,N′-tetrakis-(2-hydroxypropyl)-ethylenediamine;
• the method comprising heating a washing liquid to form a hot washing liquid;
• and
• gradually detaching the label from the article, wherein the step of gradually detaching the label from the article comprises the step of exposing the label to the hot washing liquid for at least a predetermined amount of time so that the label is reversibly curled toward the first polymeric layer thereby overcoming the adhesive force of the adhesive layer.