Multilayered polyolefin-based films having integrated backsheet and encapsulation performance comprising a layer comprising crystalline block copolymer composite or block copolymer composite

Abstract

A multilayer film structure comprising a top encapsulation layer A, a tie Layer B between top Layer A and bottom Layer C and a bottom layer C, the multilayer film structure characterized in that tie Layer B comprises a crystalline block composite resin or a block composite resin and bottom Layer C comprises a polyolefin having at least one melting point greater than 125° C.

What is claimed is: 
     
         1 . A multilayer film structure comprising a top encapsulation Layer A, a bottom Layer C and a tie Layer B between Layer A and Layer C, the multilayer film structure characterized in that Layer B comprises a crystalline block copolymer composite (CBC) or a specified block copolymer composite (BC), comprising:
 i) an ethylene polymer (EP) comprising at least 40 mol % polymerized ethylene;   ii) an alpha-olefin-based crystalline polymer (CAOP) and   iii) a block copolymer comprising (a) an ethylene polymer block comprising at least 40 mol % polymerized ethylene and (b) a crystalline alpha-olefin block (CAOB),   
       or a mixture of said composite(s); and bottom Layer C comprises a polyolefin having at least one melting point greater than 125° C. 
     
     
         2 . A multilayer film structure according to  claim 1  wherein the i) EP in tie Layer B comprises at least 80 mol % polymerized ethylene and the balance is polymerized propylene. 
     
     
         3 . A multilayer film structure according to  claim 1  wherein the block composite resin in tie Layer B is a crystalline block composite resin. 
     
     
         4 . A multilayer film structure according to  claim 1  wherein the tie Layer B block composite resin has a CAOB amount (in part (iii)) in the range of from 30 to 70 weight % of the CAOB. 
     
     
         5 . A multilayer film structure according to  claim 3  wherein the tie Layer B block composite resin has a CAOB amount (in part (iii)) in the range of from 40 to 60 weight % of the CAOB. 
     
     
         6 . A multilayer film structure according to  claim 1  where tie Layer B comprises a CBC having a CBCI of between 0.3 to 1.0 or a specified BC having a BCI of between 0.1 to 1.0. 
     
     
         7 . A multilayer film structure according to  claim 1  wherein propylene is the alpha-olefin in ii) and iii) in tie Layer B. 
     
     
         8 . A multilayer film structure according to  claim 1  wherein tie Layer B comprises a blend comprising greater than 40 weight percent CBC or specified BC. 
     
     
         9 . A multilayer film structure according to  claim 8  wherein tie Layer B is a blend further comprising one or more polyolefin selected from an ethylene octene copolymer plastomers or elastomer, LLDPE and LDPE. 
     
     
         10 . A multilayer film structure according to  claim 1  wherein the CBC or specified BC of Layer B has a melt flow rate of from 3 to 15 g/10 min (at 230° C./2.16 Kg). 
     
     
         11 . A multilayer film structure according to  claim 1  in which the top encapsulation Layer A comprises an ethylene octene copolymer plastomers or elastomer. 
     
     
         12 . A multilayer film structure according to  claim 11  in which the top encapsulation Layer A comprises a silane-graft containing ethylene octene copolymer. 
     
     
         13 . A multilayer film structure according to  claim 1  in which the bottom Layer C comprises a propylene-based polymer. 
     
     
         14 . A multilayer film structure according to  claim 13  in which the bottom Layer C comprises a propylene-based polymer having a heat of fusion value of at least 60 Joules per gram (J/g). 
     
     
         15 . A multilayer film structure according to  claim 1  comprising a top encapsulation Layer A comprising a silane-graft-containing ethylene alpha olefin copolymer, a bottom Layer C comprising a propylene-based polymer and a tie Layer B between Layer A and Layer C comprising a crystalline block copolymer composite (CBC) comprising i) an ethylene polymer (EP) comprising at least 93 mol % polymerized ethylene; ii) a crystalline propylene polymer and iii)a block copolymer comprising (a) an ethylene polymer block comprising at least 93 mol % polymerized ethylene and (b) a crystalline propylene polymer block. 
     
     
         16 . A multilayer film structure according to  claim 15  wherein tie Layer B is a blend further comprising one or more polyolefin selected from an ethylene octene copolymer plastomers or elastomer, LLDPE and LDPE. 
     
     
         17 . A multilayer film structure according to  claim 1  having a thickness of from 0.2 to 1.5 mm wherein Layer A is from 0.15 to 1.25 mm in thickness; Layer B is from 10 to 150 μm in thickness; and Layer C is from 150 to 375 μm in thickness. 
     
     
         18 . An electronic device (ED) module comprising an electronic device and a multilayer film structure according to  claim 1 . 
     
     
         19 . An electronic device (ED) module comprising an electronic device and a multilayer film structure according to  claim 16 . 
     
     
         20 . A lamination process to construct a laminated PV module comprising the steps of:
 (1.) bringing at least the following layers into facial contact in the following order:
 (a) a light-receiving top sheet layer having an exterior light-receiving facial surface and an interior facial surface; 
 (b) a light transmitting thermoplastic polymer encapsulation layer, having one facial surface directed toward the top sheet layer and one directed toward a light-reactive surface of a PV cell; 
 (c) a PV cell having a light reactive surface; 
 (d) a backsheet layer comprising a multilayer film structure according to  claim 1 ; and 
   (2.) heating and compressing the layers of Step (1.) at conditions sufficient to create the needed adhesion between the layers and, if needed in some layers or materials, initiation of their crosslinking.