Method for Producing a Photovoltaic Module

Abstract

A method for producing a photovoltaic module by contacting at least one layer of liquid encapsulant and a plurality of solar cells. The liquid encapsulant has two components. The first component is an acrylic polyol having a terminal hydroxy group, an average number of hydroxy-functional monomer units per polymer chain from 2 to 25 and Mn from 1,000 to 10,000. The second component is an aliphatic polyisocyanate with an average functionality of at least two. The molar ratio of non-terminal hydroxy groups in the polyol to isocyanate groups in the aliphatic polyisocyanate is from 0.5:1 to 1:0.5.

1 . A composition comprising: (i) an acrylic polyol having a terminal hydroxy group, an average number of hydroxy-functional monomer units per polymer chain from 2 to 25, Mn from 1,000 to 10,000, Tg from −100° C. to −40° C. and comprising from 65 to 95 wt % polymerized residues of C4-C12 alkyl (meth)acrylate and 5 to 35 wt % polymerized residues of hydroxy-containing acrylic monomer; and (ii) an aliphatic polyisocyanate with an average functionality of at least two; wherein a molar ratio of non-terminal hydroxy groups in the polyol to isocyanate groups in the aliphatic polyisocyanate is from 0.5:1 to 1:0.5. 
     
     
         2 . The composition of  claim 1  in which the acrylic polyol has an average hydroxyl functionality per polymer chain from 3 to 6. 
     
     
         3 . The composition of  claim 2  in which the acrylic polyol has Mn from 3,000 to 5,000 and from 10 to 20% residues of hydroxy-containing acrylic monomer. 
     
     
         4 . The composition of  claim 3  in which the hydroxy-containing acrylic monomer is a hydroxyalkyl (meth)acrylate. 
     
     
         5 . The composition of  claim 4  in which the hydroxy-containing acrylic monomer is hydroxyethyl methacrylate, hydroxypropyl methacrylate or a combination thereof. 
     
     
         6 . The composition of  claim 1  in which the hydroxy-containing acrylic monomer is a hydroxyalkyl (meth)acrylate. 
     
     
         7 . The composition of  claim 6  in which the hydroxy-containing acrylic monomer is hydroxyethyl methacrylate, hydroxypropyl methacrylate or a combination thereof. 
     
     
         8 . The composition of  claim 7  in which the acrylic polyol has an average hydroxyl functionality per polymer chain from 3 to 6. 
     
     
         9 . The composition of  claim 8  in which the acrylic polyol has Mn from 3,000 to 5,000 and from 10 to 20% residues of hydroxy-containing acrylic monomer.