Crosslinkable fluorinated aromatic prepolymer and its uses

Abstract

To provide a crosslinkable fluorinated aromatic prepolymer which is capable of forming a cured product having a low relative permittivity, high heat resistance, low birefringence and high flexibility, and its uses. A crosslinkable fluorinated aromatic prepolymer which is obtained by subjecting a compound (Y-1) having a crosslinkable functional group (A) and a phenolic hydroxyl group and/or a compound (Y-2) having a crosslinkable functional group (A) and a fluorinated aromatic ring, to a condensation reaction in the presence of a HF-removing agent, with a fluorinated aromatic compound (B) represented by the formula (1): (wherein n is an integer of from 0 to 2, each of a and b which are independent of each other, is an integer of 0 to 3, and each of Rf 1 and Rf 2 represents a fluorinated alkyl group having at most 8 carbon atoms and a compound (C) having at least 3 phenolic hydroxyl groups, and which has crosslinkable functional groups (A) and ether bonds and has a number average molecular weight of from 1×10 3 to 5×10 5 .

1 . A crosslinkable fluorinated aromatic prepolymer which is obtained by subjecting either one or both of a compound (Y-1) having a crosslinkable functional group (A) and a phenolic hydroxyl group and a compound (Y-2) having a crosslinkable functional group (A) and a fluorinated aromatic ring, to a condensation reaction in the presence of a HF-removing agent, with a fluorinated aromatic compound (B) represented by the following formula (1):  
       
         
           
           
               
               
           
         
       
       (wherein n is an integer of from 0 to 2, each of a and b which are independent of each other, is an integer of from 0 to 3, and each of Rf 1  and Rf 2  which may be the same or different from each other, represents a fluorinated alkyl group having at most 8 carbon atoms, and F in the aromatic ring represents that hydrogen atoms of the aromatic ring are all substituted by fluorine atoms), and a compound (C) having at least 3 phenolic hydroxyl groups, and which has crosslinkable functional groups (A) and ether bonds and has a number average molecular weight of from 1×10 3  to 5×10 5 .  
     
     
         2 . The crosslinkable fluorinated aromatic prepolymer according to  claim 1 , wherein the crosslinkable functional group (A) is an ethynyl group.  
     
     
         3 . A cured product formed by curing the crosslinkable fluorinated aromatic prepolymer as defined in  claim 1 .  
     
     
         4 . A coating composition comprising the crosslinkable fluorinated aromatic prepolymer as defined in  claim 1 , and a solvent.  
     
     
         5 . A cured film formed by forming a wet film of a crosslinkable fluorinated aromatic prepolymer on a substrate, by using the coating composition as defined in  claim 4 , and then, after removing the solvent in the wet film or at the same time as removing the solvent, curing the crosslinkable fluorinated aromatic prepolymer.  
     
     
         6 . The cured film according to  claim 5 , which contains pores in the film.  
     
     
         7 . An electric or electronic component having the cured film as defined in  claim 5.