Multilayer composite films and articles prepared therefrom

Abstract

The present invention is an optically transparent laminate film comprising: at least three layers of film, wherein at least two of the at least three layers comprise ionomeric films, and wherein the film can be suitable for use in a photovoltaic cell or in packaging.

1 . A laminate article comprising: 
 (i) a first outer layer comprising a first ionomer;    (ii) a core layer unit comprising at least one polymer layer positioned such that a first surface of the core layer unit is in direct contact with at least one surface of the first outer layer;    (iii) a second outer layer comprising a second ionomer positioned such that a second surface of the core layer unit is in direct contact with at least one surface of the second outer layer;    wherein the at least one core layer polymer is a non-ionomeric polymer and wherein the individual optical transmittance for each of the first ionomer layer, the second ionomer layer, the core layer unit, and the laminate at the same wavelength can each be measured, and wherein the measured transmittance for the laminate is greater than the expectation value of the transmittance calculated from the transmittance of the three individual layers in their non laminated state weighted by their thicknesses in the laminate.    
     
     
         2 . The laminate article of  claim 1  wherein the first and second ionomers comprise identical compositions.  
     
     
         3 . The laminate article of  claim 1  wherein the optical transmittance of the laminate material of light of 500 nm wavelength is greater than 85%.  
     
     
         4 . The laminate article of  claim 1  which shows a DMA transition temperature of greater than 65° C. at 1 Hz.  
     
     
         5 . The laminate article of  claim 5  wherein the core layer polymer shows a DMA transition temperature of less than 40° C. at 1 Hz when not laminated to the outer layers.  
     
     
         6 . The laminate article of  claim 1  wherein the core layer polymer is a laminate.  
     
     
         7 . The laminate article of  claim 1  wherein the core layer polymer comprises a polymer selected from the group consisting of: polyurethane; ethylene vinyl acetate (EVA); polyvinyl chloride (PVC); polyester; polyacetals; ethylene acid copolymers (which can be inclusive of ethylene acid terpolymers or higher copolymers), ethylene acrylate copolymers (which can be inclusive of terpolymers and higher copolymers) and blends, laminates or combinations thereof.  
     
     
         8 . The laminate article of  claim 1  wherein the first and second ionomers independently comprise copolymers obtained by the copolymerization of ethylene and an ethylenically unsaturated C 3 -C 8  carboxylic acid.  
     
     
         9 . The laminate article of  claim 1  wherein the first and second ionomers independently comprise an acid copolymer that includes from about 8 wt % to about 25 wt % of the acid, based on the total weight of the copolymer.  
     
     
         10 . The laminate article of  claim 9  wherein the first and second ionomers independently comprise an acid copolymer that includes from about 11 wt % to about 25 wt % of the acid, based on the total weight of the copolymer.  
     
     
         11 . The laminate article of  claim 10  wherein the first and second ionomers independently comprise an acid copolymer that includes from about 14 wt % to about 19 wt % of the acid, based on the total weight of the copolymer.  
     
     
         12 . The laminate article of  claim 11  wherein the first and second ionomers independently comprise an acid copolymer that includes from about 15 wt % to about 19 wt % of the acid, based on the total weight of the copolymer.  
     
     
         13 . An optically transparent laminate film comprising: at least three layers of film, wherein (a) at least two of the at least three layers comprise ionomeric films, (b) at least one layer of the laminate independently in a non laminated state (i) transmits less than about 85% incident visible light and/or (ii) has a haze value of equal to or greater than about 6% as measured according to ASTM D1003-00 on the at least one layer having a thickness of about 40 mil or less and (c) the transparent laminate (i) transmits at least about 85% of incident visible light and/or (ii) has a haze value of equal to or less than about 6% as measured according to ASTM D1003-00.  
     
     
         14 . An article comprising the optically transparent laminate film of  claim 13 .  
     
     
         15 . The article of  claim 14  wherein the article is a package or container.  
     
     
         16 . The article of  claim 15  wherein the article comprises one or more layers of glass laminated to at least one of the ionomeric films.  
     
     
         17 . A solar cell module comprising: (a) at least one solar cell and (b) a transparent encapsulant material disposed adjacent to at least one surface of the solar cell, the encapsulant material comprises a laminate of  claim 1 , wherein the solar cell module further comprises a front support layer formed of light transmitting material disposed adjacent a front surface of the encapsulant material and a backskin layer disposed adjacent a rear surface of the encapsulant material.  
     
     
         18 . The solar cell module of  claim 17  comprising a plurality of interconnected solar cells.  
     
     
         19 . A laminate article comprising: 
 (i) a first outer layer that comprises a first ionomer;    (ii) a core layer unit comprised of at least one core layer polymer located with a first surface next to a surface of the first outer layer;    (iii) a second outer layer that comprises a second ionomer located next to a second surface of the core layer unit,    wherein the core layer polymer is not an ionomer and the laminate material, the first and second ionomers and the core layer polymer can be characterized by their transition temperature measured under tensile conditions at 1 Hz by DMA such that the value of the transition temperature for the laminate material is greater than the value of the transition temperature of the core layer polymer measured under identical conditions and not in the laminate.    
     
     
         20 . The laminate article of  claim 19  wherein the first and second ionomers are the same.  
     
     
         21 . The laminate article of  claim 20  having a DMA transition temperature of greater than 65° C. at 100 Hz.  
     
     
         22 . The laminate article of  claim 21  wherein the core layer polymer has a DMA transition temperature of less than 40° C. at 100 Hz when not laminated to the outer layers.  
     
     
         23 . The laminate article of  claim 22  wherein the core layer polymer is a laminate.  
     
     
         24 . The laminate article of  claim 23  wherein the core layer polymer comprises a polymer selected from the group consisting of polyurethane; ethylene vinyl acetate (EVA); polyvinyl chloride (PVC); polyester; polyacetals; ethylene acid copolymers (which can be inclusive of ethylene acid terpolymers or higher copolymers); ethylene acrylate copolymers (which can be inclusive of terpolymers and higher copolymers), and blends or combinations thereof.  
     
     
         25 . The laminate article of  claim 24  wherein the first and second ionomers independently comprise copolymers obtained by the copolymerization of ethylene and an ethylenically unsaturated C 3 -C 8  carboxylic acid.  
     
     
         26 . The laminate article of  claim 25  wherein the first and second ionomers are independently comprise an acid copolymer that includes from about 8 wt % to about 25 wt % of the acid, based on the total weight of the copolymer.  
     
     
         27 . The laminate article of  claim 26  wherein the first and second ionomers are independently comprise an acid copolymer that includes from about 11 wt % to about 25 wt % of the acid, based on the total weight of the copolymer.  
     
     
         28 . The laminate article of  claim 27  wherein the first and second ionomers are independently comprise an acid copolymer that includes from about 14 wt % to about 19 wt % of the acid, based on the total weight of the copolymer.  
     
     
         29 . The laminate article of  claim 28  wherein the first and second ionomers independently comprise an acid copolymer that includes from about 15 wt % to about 19 wt % of the acid, based on the total weight of the copolymer.