Method for forming multilayer release liners and liners formed thereby

Abstract

Disclosed herein is a multilayer silicone release surface comprising a backing, a support layer on the backing, and a silicone layer of the support layer. The various layers of the multilayer release surface are deposited substantially simultaneously, as for example by a dual die or using curtain coating techniques.

1 . A method of making a multilayer release liner, comprising: 
 depositing a support layer on a backing; and    substantially simultaneously depositing a release layer on the support layer, wherein the layers are deposited by curtain coating.    
     
     
         2 . The method of  claim 1 , wherein the release layer comprises silicone.  
     
     
         3 . A method of applying a multilayer release liner to a backing, said method comprising: 
 providing a curtain coating die having a face surface and at least first and second die slots opening into the face surface;    moving the backing past the curtain coating die in a position so that the second die slot is between the backing and the first die slot;    expressing a support layer from the second die slot so that the support layer flows onto the face surface and towards the backing;    expressing from the first die slot a release layer that comprises silicone so that the release layer flows along a portion of the face surface between the first and second die slots and further flows onto portions of the support layer flowing towards the backing; and    curtain coating the support layer and the release layer simultaneously from the curtain coating die and onto the backing as the backing moves past the curtain coating die so that the support layer secures to the backing and so that the release layer secures to a surface of the support layer opposite the backing.    
     
     
         4 . The method of  claim 3 , wherein the backing moves at a web speed in a range of 60 m/min-1200 m/min.  
     
     
         5 . The method of  claim 4 , wherein the web speed of the backing is about 350 m/min.  
     
     
         6 . The method of  claim 3 , wherein the face surface is aligned to a direction of movement of the web at an acute angle of between 20°-45°.  
     
     
         7 . The method of  claim 3 , wherein the support layer is coated to a weight of approximately 6 g/m 2 .  
     
     
         8 . The method of  claim 7 , wherein the release layer is coated to a weight of approximately 4 g/m 2 .  
     
     
         9 . The method of  claim 3 , wherein the release layer is a silicone/SBR mixture with a ratio of 30:70 silicone to SBR.  
     
     
         10 . The method of  claim 3 , wherein the support layer and the release layer are expressed from the curtain coating die at flow rates of between 6-7 L/(m.min).  
     
     
         11 . The method of  claim 3 , further comprising the step of impeding air flow behind the curtain of the support layer and the release layer at locations between the backing and the curtain coating die for maintaining a laminar layer of air dragged in by the moving backing.  
     
     
         12 . The method of  claim 3 , further comprising deaerating the support layer and the release layer prior to expressing the layers from the curtain coating die.