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.

1 . A facestock/adhesive construction for a plastic, glass, cardboard, or metal article comprising:
 a face layer, wherein the face layer is formed from a facestock material selected from paper facestocks, olefin polymer facestocks, polystyrene facestocks, or PET facestocks; and   an adhesive layer,   wherein the facestock is able to be removed from a plastic, glass, cardboard, or metal article in a manner that enables recycling of the plastic, glass, cardboard, or metal article.   
     
     
         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 in 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 any  claim 1 , wherein the adhesive is a tacky, emulsion pressure-sensitive adhesive polymer. 
     
     
         7 . The facestock/adhesive construction of  claim 1 , wherein the adhesive is a tacky, emulsion pressure-sensitive adhesive polymer comprising, on a polymerized basis and based on the total weight of the polymer, at least one alkyl acrylate containing from about 4 to about 8 carbon atoms in the alkyl group, the alkyl acrylate present in a total amount of from about 35 weight percent to about 60 weight percent; at least one vinyl ester containing from 2 to about 16 carbon atoms in the alkyl chain of the acid, the vinyl ester present in a total amount of from about 15 weight percent to about 35 weight percent; at least one diester of a dicarboxylic acid wherein each alkyl group of the diester independently contains from about 6 to about 12 carbon atoms, the diesters being present in a total amount of from about 20 weight percent to about 40 weight percent; up to about 5 weight percent of an unsaturated carboxylic acid containing from 3 to about 5 carbon atoms, wherein the emulsion polymer has a glass transition temperature of less than about −30° C. and a gel content of from about 50 to about 70 weight percent of the polymer. 
     
     
         8 . The facestock/adhesive construction of  claim 7 , wherein the adhesive comprises about 1 to about 3 weight percent of the unsaturated carboxylic acid. 
     
     
         9 . The facestock/adhesive construction of  claim 1 , wherein the adhesive is an acrylic emulsion polymer system comprising a copolymer of about 15 weight percent to about 35 weight percent of vinyl acetate, about 20 weight percent to about 40 weight percent of di-2-ethylhexyl maleate, about 35 weight percent to about 60 weight percent 2-ethylhexyl acrylate and about 1 weight percent to about 3 weight percent of one or more unsaturated carboxylic acids for each 100 parts by weight of polymer, and about 3 weight percent to about 20 weight percent of acidic rosin derivative provided as tackifier and about 1 weight percent to about 10 weight percent of a rosin based surfactant based on 100 parts of the adhesive composition. 
     
     
         10 . The facestock/adhesive construction of  claim 1 , wherein the adhesive is an acrylic emulsion pressure-sensitive copolymer latex comprising butyl acrylate, 2-ethylhexyl acrylate and mixtures thereof with an unsaturated carboxylic acid that is stabilized via nonylphenol polyethylene glycol and partially hydrolyzed polyvinyl alcohol, having a mean particle size greater than about 1 micron and a particle size range of about 0.5 microns to about 3.0 microns, having a glass transition temperature value of about −48° C. to about −55° C. 
     
     
         11 . The facestock/adhesive construction of  claim 1 , wherein the adhesive is 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. 
     
     
         12 . The facestock/adhesive construction of  claim 1 , wherein the adhesive is an acrylic emulsion polymer comprising at least one acrylate ester of an alcohol containing at least four carbon atoms, at least one partially water soluble comonomer and at least one polar comonomer. 
     
     
         13 . The facestock/adhesive construction of  claim 1 , wherein the adhesive is a polymer produced by copolymerizing a mixture of monomers comprising at least one monomer selected from alkyl acrylate esters containing from about 4 to about 12 carbon atoms in the alkyl group with such one or more alkyl acrylates present in a total amount from about 90 weight percent to about 98 weight percent with up to about 5 weight percent of an unsaturated polar acrylate monomer that contains from 3 to 5 carbon atoms and in one instance at least one hydroxyl group. 
     
     
         14 . The facestock/adhesive construction of  claim 1 , wherein the adhesive is a polymer produced by copolymerizing a mixture of monomers comprising at least one monomer selected from the group of alkyl acrylate esters containing from about 4 to about 12 carbon atoms in the alkyl group where such one or more alkyl acrylate esters are present in a total amount from about 65 weight percent to about 80 weight percent with at least one vinyl ester containing from 2 to about 16 carbon atoms in the alkyl chain of the acid, with such said vinyl acetate present in a total amount of from about 15 to about 35 percent by weight, and up to about 5 weight percent of an unsaturated carboxylic acid contains from 3 to 5 carbon atoms. 
     
     
         15 . The facestock/adhesive construction of  claim 1 , wherein the adhesive is an emulsion of acrylic and rubber polymers that provides high adhesion and high tack to polar and nonpolar substrates with excellent cohesion, wherein the adhesive is modified by rosin-based acidic tackifiers and rosin-based surfactants. 
     
     
         16 . The facestock/adhesive construction of  claim 1 , wherein the facestock/adhesive construction is able to be removed by a caustic solution. 
     
     
         17 . The facestock/adhesive construction of  claim 1 , wherein the facestock/adhesive construction is able to be removed by a caustic solution selected from NaOH, KOH, LiOH, MgOH, CaOH, or suitable mixtures of two or more thereof. 
     
     
         18 . The facestock/adhesive construction of  claim 1 , wherein the caustic solution further comprises at least one surfactant. 
     
     
         19 . The facestock/adhesive construction of  claim 1 , wherein the caustic solution further comprises at least one nonionic surfactant. 
     
     
         20 . 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 any one of  claims 1  to  19 ; 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.   
     
     
         21 . The method of  claim 20 , 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.   
     
     
         22 . A facestock/adhesive construction for a plastic, glass, cardboard, or metal article comprising:
 a face layer; and   an adhesive layer,   wherein the facestock is able to be removed from a plastic, glass, cardboard, or metal article in a manner that enables recycling of the plastic, glass, cardboard, or metal article.   
     
     
         23 . A facestock/adhesive construction or label for a plastic, glass, cardboard, or metal article as shown and/or described herein. 
     
     
         24 . A method for removing a facestock/adhesive construction or label from a plastic, glass, cardboard, or metal article in order to facilitate recycling of the plastic, glass, cardboard, or metal article as shown and/or described herein. 
     
     
         25 . An adhesive composition as shown and/or described herein for use in conjunction with a label, or print, layer in a facestock, wherein the adhesive composition is designed to be removable from a plastic, glass, cardboard, or metal article without adversely affecting the ability of the plastic, glass, cardboard, or metal article to be recycled.