Prelaminate pressure-sensitive adhesive constructions

Abstract

Prelaminate pressure-sensitive adhesive (PSA) constructions comprise, a first substrate, a coating or release material on a surface of the first substrate, a PSA layer disposed on the coating of release material, and a detackified layer (DL) disposed on a surface of the PSA layer to form a continuous film covering the PSA layer. In first and second embodiments of the construction the DL is activatable to form a tacky layer on top of the PSA layer for lamination with a second substrate. In a third embodiment, the DL includes constituents that when activated migrate into the PSA layer to expose the PSA layer tacky surface for lamination with a second substrate. The prelaminate PSA constructions are completely nonblocking to a minimum 24 hour blocking temperature of about 50° C. at pressure of about 40 kilopascals, thereby allowing such prelaminate PSA construction to be collected, stored, and or transported before being laminated without adhesive interference occurring between continuous layers. The DL in each embodiment is activatable in less than five seconds to provide a tacky layer having a sufficient open tack time to permit lamination at less than about 100° C.

1 . A method for forming a pressure-sensitive adhesive construction comprising the steps of: 
 a) depositing a layer of pressure-sensitive adhesive material onto a coating or release material that is disposed on a surface of a first flexible substrate; and    b) applying a layer of continuous film forming material onto a surface of the pressure-sensitive adhesive layer to render the pressure sensitive adhesive construction completely nonblocking, the continuous film forming material being applied to the pressure-sensitive adhesive at substantially the same time that the pressure-sensitive adhesive material is deposited.    
   
   
       2 . The method as recited in  claim 1  wherein the layer of continuous film forming material is applied in the form of a hot melt or an emulsion.  
   
   
       3 . The method as recited in  claim 1  wherein the layer of continuous film forming material is applied in the form of a hot melt and has a hot melt viscosity that is within a factor of about two times a hot melt viscosity for the pressure sensitive adhesive.  
   
   
       4 . The method as recited in  claim 1  further comprising the step of activating the continuous film forming material to form a tacky surface independent of the pressure sensitive adhesive for supporting adhesion to a second substrate.  
   
   
       5 . The method as recited in  claim 4  wherein the step of activating is achieved by heat.  
   
   
       6 . The method as recited in  claim 4  wherein the activated continuous film is laminated to a second substrate at a temperature of less than about 100° C.  
   
   
       7 . The method as recited in  claim 4  wherein the continuous film forming material is activated for lamination in less than about five seconds.  
   
   
       8 . A pressure-sensitive laminate construction prepared according to the method of  claim 1 .  
   
   
       9 . A method for forming a laminated pressure-sensitive adhesive construction comprising the steps of: 
 a) depositing a layer of pressure-sensitive adhesive material onto a coating or release material that is disposed on a surface of a first flexible substrate; and    b) applying a detackifying material onto a surface of the pressure-sensitive adhesive layer to occlude the pressure-sensitive adhesive layer and form a nonblocking detackified pressure-sensitive adhesive construction, the detackifying material being heat activatable;    c) heating the detackifying material to an activation temperature to provide a tacky surface independent of the pressure-sensitive adhesive for lamination; and    d) laminating a second substrate to the tacky surface of the detackifying material at a temperature less than about 100° C. to form a laminated pressure-sensitive adhesive construction having the second substrate;    wherein the step of depositing and applying occur at substantially the same time.    
   
   
       10 . The method as recited in  claim 9  wherein during the step of heating, the tacky surface has an open tack time in the range of from 0.25 to 5 seconds.  
   
   
       11 . The method as recited in  claim 9  wherein before the step of heating, the detackifying material is heat treated by heating to a temperature below an activation temperature.  
   
   
       12 . The method as recited in  claim 9  further comprising, between the step of applying and heating, the steps of: 
 collecting the detackified pressure-sensitive adhesive construction by placing the detackified pressure-sensitive adhesive adjacent to a contiguous surface of the first flexible substrate; and    removing the collected detackified pressure-sensitive adhesive from the contiguous first flexible substrate surface.    
   
   
       13 . A pressure-sensitive adhesive prepared according to the method recited in  claim 9 .  
   
   
       14 . A method for forming a laminated pressure-sensitive adhesive construction comprising the steps of: 
 a) heating a detackified prelaminate pressure-sensitive adhesive construction to an activation temperature to form a tacky surface for lamination, said pressure-sensitive adhesive construction comprising: 
 a first substrate comprising a coating of release material disposed thereon;  
 a pressure-sensitive adhesive disposed on the coating of release material; and  
 a continuous film layer disposed on a surface of the pressure-sensitive adhesive to occlude the pressure-sensitive adhesive layer, the continuous film layer being, in combination with the pressure-sensitive adhesive, self supporting and forming a tacky surface independent of the pressure-sensitive adhesive upon heating to an activation temperature; and  
   b) laminating a second substrate to the tacky surface of the activated continuous film layer to form a laminated pressure-sensitive adhesive construction;    wherein the continuous film layer is applied to the pressure-sensitive adhesive while the pressure-sensitive adhesive is not fully cured.    
   
   
       15 . The method as recited in  claim 14  wherein the continuous film layer forms a bond with the pressure-sensitive adhesive that is stronger than a bond formed with the second substrate to facilitate preferential removal of the second substrate from the continuous film layer and pressure sensitive adhesive during paper reclamation.  
   
   
       16 . The method as recited in  claim 14  wherein during the step of heating, the tacky surface is formed in less than about five seconds.  
   
   
       17 . The method as recited in  claim 14  wherein the step of laminating takes place in the range of from 0.25 to 5 seconds after the step of heating.  
   
   
       18 . The method as recited in  claim 14  further comprising between the steps of heating and laminating, placing an object on the tacky surface.