Fluid Activatable Adhesive for Glue-Free, Liner-Free, Labels for Glass and Plastic Substrates and Methods of Use Thereof

Abstract

Methods for applying a liner-free, or liner-less label, to a substrate, particularly glass or plastic (e.g., polyethylene terephthalate) substrates, are described herein. The method includes applying an adhesive composition, such as a polymeric coating, to a label face sheet, activating the adhesive composition with an activating fluid, and contacting the label to the substrate. The activating fluid is preferably a mixture of water and one or more organic solvents, such as low molecular weight alcohols.

We claim: 
     
         1 . A liner-free label comprising a non-tacky polymeric coating on a face sheet,
 wherein the polymeric coating comprises one or more alkaline soluble polymers selected from the group consisting of styrene-maleic anhydride resins, esters of styrene-maleic anhydride resins, styrene-maleic anhydride amic acid resins, styrene-maleic anhydride imide resins, ammonium and alkali metal salts of styrene-maleic anhydride resins, and combinations thereof and one or more emulsion polymers,   wherein the one or more alkaline soluble polymers are water-insoluble at neutral pH.   
     
     
         2 . The liner-free label of  claim 1 , wherein the emulsion polymer comprises a styrene acrylic polymer. 
     
     
         3 . The liner-free label of  claim 1 , wherein the face sheet is printed or printable paper. 
     
     
         4 . The liner-free label of  claim 1 , wherein the face sheet is a printed or printable polymeric film. 
     
     
         5 . The liner-free label of  claim 1 , wherein the alkaline soluble polymer comprises styrene-maleic anhydride resins. 
     
     
         6 . The liner-free label of  claim 1 , wherein the face sheet has a moisture vapor transmission rate of at least about 160 g/m 2 /24 hr. 
     
     
         7 . The liner-free label of  claim 1 , wherein the label exhibits no blocking after 90 seconds at 60 psi and 120-122° F. 
     
     
         8 . The liner-free label of  claim 1 , wherein the polymer coating further comprises a hygroscopic particulate filler selected from the group consisting of alumina, alumina gel, boehmite, pseudoboehmite, clay, calcium carbonate, chalk, magnesium carbonate, kaolin, calcined clay, pyropylate, bentonite, zeolite, talc, silica, silica gel, synthetic aluminum silicates, synthetic calcium silicates, diatomatious earth, anhydrous silicic acid powder, aluminum hydroxide, barite, barium sulfate, gypsum, calcium sulfate, polyamides, polyvinyl alcohol, polyvinylpyrrolidone, polyvinylpyrrolidone vinyl acetate, and combinations thereof. 
     
     
         9 . A liner-free label attached to a polyethylene terephthalate or glass substrate, wherein the liner-free label comprises a polymeric coating on a face sheet,
 wherein the polymeric coating comprises one or more alkaline soluble polymers selected from the group consisting of styrene-maleic anhydride resins, esters of styrene-maleic anhydride resins, styrene-maleic anhydride amic acid resins, styrene-maleic anhydride imide resins, ammonium and alkali metal salts of styrene-maleic anhydride resins, and combinations thereof and one or more emulsion polymers,   wherein the one or more alkaline soluble polymers are water-insoluble at neutral pH, and   wherein the polymeric coating serves as an adhesive composition that attaches the label to the polyethylene terephthalate or glass substrate.   
     
     
         10 . The liner-free label of  claim 9 , wherein the face sheet is printed or printable paper. 
     
     
         11 . The liner-free label of  claim 9 , wherein the face sheet is a printed or printable polymeric film. 
     
     
         12 . The liner-free label of  claim 10 , wherein the label has greater than 50% fiber tear after 2 minutes. 
     
     
         13 . The liner-free label of  claim 10 , wherein the label has greater than 75% fiber tear after 2 minutes. 
     
     
         14 . The liner-free label of  claim 9 , wherein the label exhibits no label drop-off after 72 hours immersed in ice water. 
     
     
         15 . The liner-free label of  claim 14 , wherein the label has complete label drop-off after soaking in 0.5% to 5% sodium hydroxide solution at 65° C. to 75° C. for less than 5 minutes. 
     
     
         16 . The liner-free label of  claim 9 , wherein prior to contact with the substrate, the polymeric coating is activated by an activating fluid to form the adhesive composition. 
     
     
         17 . The liner-free label of  claim 16 , wherein the activation fluid comprises water and one or more organic solvents. 
     
     
         18 . The liner-free label of  claim 17 , wherein activation fluid composition comprises 5% to 70% by weight of one or more low boiling alcohol(s). 
     
     
         19 . The liner free-label of  claim 18 , wherein the activation fluid composition comprises 10 to 30% by weight of one or more low boiling alcohol(s). 
     
     
         20 . The liner-free label of  claim 18 , wherein at least one low boiling alcohol is n-propanol or isopropanol.