Adhesive Acrylate-Olefin Copolymers, Methods for Producing Same and Compositions Utilizing Same

Abstract

The present invention relates to an adhesive compositions, facestocks and/or packaging labels containing same, where such compositions, facestocks and/or labels are designed to facilitate the recyclability of a plastic article formed from any suitable polymer or mixture of polymers (e.g., a polyethylene terephthalate (PET), high density polyethylene (HDPE), polyvinyl chloride (PVC), low density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), or others of all plastic types), or even glass bottles. In another embodiment, the present invention relates to a method for removing an adhesive composition, facestock and/or packaging label containing same, from a plastic article that is to be recycled.

What is claimed is: 
     
         1 . A facestock/adhesive construction for a plastic, glass, cardboard, or metal article, the construction comprising:
 a face layer, wherein the face layer is formed from a facestock material selected from olefin polymer facestocks, polystyrene facestocks, or PET facestocks, the facestock having a shrink force; and   an adhesive layer adhered to the article, the adhesive having a retention force to the article,
 wherein the adhesive retention force to the article is greater than the facestock shrink force in the presence of a caustic solution; and 
   wherein the adhesive layer comprises a homogeneous dispersion comprising an anionic/non-ionic emulsion pressure-sensitive copolymer latex of 2-ethylhexyl acrylate and other alkyl acrylates and styrene with at least one unsaturated carboxylic acid, including tackifiers comprising a mixture of hydrogenated rosin and tall oil esters, wherein other alkyl acrylates are selected from the group consisting of methyl acrylate, methyl methacrylate, and mixtures thereof.   
     
     
         2 . The facestock/adhesive construction of  claim 1 , wherein the olefin polymer facestocks is selected from polyethylene facestocks or polypropylene facestocks. 
     
     
         3 . The facestock/adhesive construction of  claim 1 , wherein the face layer is formed from a facestock having two or more layers of the facestock material. 
     
     
         4 . The facestock/adhesive construction of  claim 1 , wherein the facestock material of the face layer is either unaxially oriented, biaxially oriented, or unoriented. 
     
     
         5 . The facestock/adhesive construction of  claim 1 , wherein the facestock material of the face layer is unoriented. 
     
     
         6 . The facestock/adhesive construction of  claim 1 , wherein the facestock/adhesive construction is removable from the article by the caustic solution, the caustic solution selected from NaOH, KOH, LiOH, MgOH, CaOH, or mixtures of two or more thereof. 
     
     
         7 . The facestock/adhesive construction of  claim 1 , wherein the caustic solution further comprises at least one surfactant. 
     
     
         8 . The facestock/adhesive construction of  claim 1 , wherein the caustic solution further comprises at least one nonionic surfactant. 
     
     
         9 . The facestock/adhesive construction of  claim 1 , wherein the article is formed from PET, the article having a shrink force greater than the adhesive retention force in the presence of the caustic solution. 
     
     
         10 . A method of removing the facestock/adhesive construction of  claim 1 , wherein the method comprises the steps of:
 (a) supplying at least one article to be later recycled, the article having attached thereto at least one facestock/adhesive construction according to  claim 1 ; and   (b) subjecting the article containing the at least one facestock/adhesive construction to at least one caustic solution until the facestock/adhesive construction releases from the article to be recycled.   
     
     
         11 . The method of  claim 10 , wherein the method further comprises the steps of:
 (c) separating the removed one or more facestock/adhesive construction from the article to be recycled; and   (d) optionally washing the article to be recycled to remove any remaining caustic solution prior to further recycling steps.