Patent attributes
A crosslinkable fluorinated aromatic prepolymer which is capable of forming a cured product having high transparency, a low relative permittivity, high heat resistance, low birefringence and high flexibility, and which is obtained by subjecting a compound (Y-1) having a polymerizable double bond (A) and/or a phenolic hydroxyl group and a compound (Y-2) having a polymerizable double bond (A) and a fluorinated aromatic ring, to a condensation reaction in the presence of a HF-removing agent, with a particular fluorinated aromatic compound (B) and a compound (C) having at least 3 phenolic hydroxyl groups, the respective phenolic hydroxyl groups not being present in the same aromatic ring, and which has polymerizable double bonds (A) and ether bonds and has a number average molecular weight of from 1×103 to 5×105.