Apparatus for manufacturing multilayer polymeric films

Abstract

A feedblock including a first packet creator that forms a first packet including a first plurality of polymeric layers, the first plurality of layers including at least four first individual polymeric layers; and a second packet creator that forms a second packet including a second plurality of polymeric layers, the second plurality of layers including at least four second individual polymeric layers, wherein the first and second packet creators are configured such that, for each packet creator, respective individual polymeric layers of the plurality of polymeric layers are formed at approximately the same time. The feedblock may include a packet combiner that receives and combines the first and second primary packets to form a multilayer stream. In some examples, at least one of the first and second primary packets may be spread in the cross-web direction prior to being combined with one another.

1 . A method for manufacturing a multilayer film using an assembly, wherein the assembly includes a primary packet creator section and an extrusion die including a first flow channel and a second flow channel, the method comprising:
 orienting, via the primary packet creator section, polymeric material to form a first primary packet including a first plurality of polymeric layers stacked on each other and to form a second primary packet including a second plurality of polymeric layers stacked on each other;   receiving the first primary packet via the first flow channel, the first primary packet including a first plurality of polymeric layers;   receiving the second primary packet via the second flow channel, the second packet including the second plurality of polymeric layers;   spreading, via the extrusion die, at least one of the first primary packet and second primary packet in a cross-web direction to an extended width; and   combining, via the extrusion die, the first primary packet and second primary packet with one another after spreading at least one of the first packet and second packet in the cross-web direction to form a multilayer flow including the first and second plurality of polymeric layers.   
     
     
         2 . The method of  claim 1 , wherein the first channel includes a first spreading manifold configured to spread the first primary packet in the cross-web direction and the second channel includes a second spreading manifold configured to spread the second primary packet in the cross-web direction. 
     
     
         3 . The method of  claim 2 , wherein the first and second spreading manifolds are formed by an extrusion die configured to combine the first and second primary packets. 
     
     
         4 . The method of  claim 1 , further comprising:
 receiving an additional layer flow via a third flow channel; and   combining the additional layer flow with the first and second primary packets to form the multilayer flow stream.   
     
     
         5 . The method of  claim 4 , wherein the additional layer flow comprises a core layer flow for forming a core layer between the first and second primary packets in the multilayer flow stream. 
     
     
         6 . The method of  claim 4 , wherein the additional layer flow comprises at least one skin layer flow for forming at least one skin layer adjacent to at least one of the first packet or the second packet in the multilayer flow stream. 
     
     
         7 . The method of  claim 4 , further comprising combining the additional layer flow with at least one of the first primary packet or second primary packet prior to spreading the at least one first primary packet or second primary packet in the cross-web direction. 
     
     
         8 . The method of  claim 4 , further comprising spreading the additional layer flow in the cross-web direction prior to combining the additional layer flow with the first and second primary packets. 
     
     
         9 . The method of  claim 1 , further comprising:
 generating the first primary packet via a first packet generator, the first primary packet having a first cross-web width;   generating the second primary packet via a second packet creator, the second packet having a second cross-web width,   wherein receiving the first primary packet via the first flow channel comprises receiving the first packet having the first cross-web width via the first flow channel, and receiving the second primary packet via the second flow channel comprises receiving the second packet having the second cross-web width via the second flow channel, and   wherein spreading the at least one of the first primary packet and second primary packet in a cross-web direction comprising spreading the first primary packet to a third cross-web width greater than the first cross-web width and spreading the second primary packet to a fourth cross-web width greater than the second cross-web width.   
     
     
         10 . The method of  claim 1 , wherein the first and second packets have substantially the same cross-web width when combined with one another. 
     
     
         11 . The method of  claim 1 , further comprising manufacturing the multilayer flow stream into a multilayer optical film.