Faceless pressure-sensitive adhesive construction

Abstract

Faceless PSA label constructions of this invention comprise a flexible substrate having a release surface, and a layer of pressure-sensitive adhesive disposed on the release surface. A nonblocking continuous film that, in combination with the pressure-sensitive adhesive is sufficiently self supporting, is disposed over a surface of the layer of pressure-sensitive adhesive to render the pressure-sensitive adhesive tack free. The continuous film is selected from the group of film-forming polymers consisting of polyamide resins, polyester resins, polyurethane resins, polyacrylate resins, vinyl acetate resins and mixtures thereof having a tensile strength of at least 200 psi, and a percent elongation of at least 50. The continuous film can be applied sequentially or simultaneously with the PSA. For purposes of simultaneous application it is desired that the continuous film be formed from a material having a hot melt viscosity that is within a factor of about two times a hot melt viscosity for the PSA. The completed faceless PSA label construction is adapted to receive and retain printing or marking indicia directly onto a surface of the continuous film.

What is claimed is:  
     
         1 . A pressure-sensitive adhesive construction comprising: 
 a flexible substrate;    a pressure-sensitive adhesive material disposed on the flexible substrate;    a layer of releasable material interposed between the flexible substrate and the pressure-sensitive adhesive material;    a continuous film layer disposed onto a surface of the pressure-sensitive adhesive material to render the pressure-sensitive adhesive nonblocking, the continuous film layer being provided as a film-forming thermoplastic material;    wherein the combined pressure-sensitive adhesive layer and continuous film layer is sufficiently self supporting to facilitate conversion and dispensing of the construction.    
     
     
         2 . The pressure-sensitive adhesive construction as recited in  claim 1  wherein the continuous film layer is printable.  
     
     
         3 . The pressure-sensitive adhesive construction as recited in  claim 1  wherein the continuous film layer has a thickness of less than about 100 micrometers.  
     
     
         4 . The pressure-sensitive adhesive construction as recited in  claim 1  wherein the pressure-sensitive adhesive material and continuous film layer have a combined thickness of less than about 225 micrometers.  
     
     
         5 . The pressure-sensitive adhesive construction as recited in  claim 4  wherein the pressure-sensitive adhesive material and continuous film layer have a combined thickness of less then about 150 micrometers.  
     
     
         6 . The pressure-sensitive adhesive construction as recited in  claim 1  wherein the continuous film layer has a tensile strength of at least 200 psi.  
     
     
         7 . The pressure-sensitive adhesive construction as recited in  claim 6  wherein the continuous film layer has a tensile strength of less than about 2,000 psi.  
     
     
         8 . The pressure-sensitive adhesive construction as recited in  claim 1  wherein the continuous film layer has a percent elongation of at least 50.  
     
     
         9 . The pressure-sensitive adhesive construction as recited in  claim 8  wherein the continuous film layer has a percent elongation of less than about 500.  
     
     
         10 . The pressure-sensitive adhesive construction as recited in  claim 1  wherein the film-forming thermoplastic used to form the continuous film layer is selected from the group consisting of polyamide resins, polyester resins, polyurethane resins, polyacrylate resins, vinyl acetate resins, and mixtures thereof.  
     
     
         11 . A method for the continuous production of a pressure-sensitive adhesive construction, the method comprising the steps of: 
 applying a layer of pressure-sensitive adhesive material onto a flexible substrate, wherein a layer of releasible material is interposed between the flexible substrate and the pressure-sensitive adhesive; and    applying a layer of film-forming thermoplastic material onto a surface of the pressure-sensitive adhesive to render the pressure-sensitive adhesive material tack free;    wherein the combined layer of pressure-sensitive adhesive material and layer of film-forming thermoplastic material is sufficiently self supporting to facilitate conversion and dispensing of the construction.    
     
     
         12 . The method as recited in  claim 11  further comprising, prior to the step of applying the pressure-sensitive adhesive material, the step of dispensing the flexible substrate in the form of a continuous web.  
     
     
         13 . The method as recited in  claim 11  further comprising, subsequent to the step of applying the layer of film-forming thermoplastic material, the step of collecting the pressure-sensitive construction in the form of a continuous web.  
     
     
         14 . The method as recited in  claim 11  wherein the steps of applying are carried out in a single step simultaneously.  
     
     
         15 . The method as recited in  claim 11  wherein the film-forming thermoplastic material is applied before the pressure-sensitive adhesive material is fully developed.  
     
     
         16 . The pressure-sensitive adhesive construction as recited in  claim 11  wherein the film-forming thermoplastic material is selected from the group consisting of polyamide resins, polyester resins, polyurethane resins, polyacrylate resins, vinyl acetate resins, and mixtures thereof.