COATING LIQUID FOR FORMING INSULATION FILM

PROBLEM TO BE SOLVED: To obtain the subject coating liquid which is capable of forming a thermosetting insulation film on various substrates containing electronic devices at relatively low permittivity by including a polyether resin which has a specific structural unit and a specific structure at the end of the resin. SOLUTION: This coating liquid is obtained by including a polyether resin which has a structural unit of formula I (R1 to R4 are each hydrogen, fluorine, a 1-6C fluorine-substituted alkyl, a 4-8C fluorine-substituted cycloalkyl, except that all of R1 to R4 are hydrogen atoms at the same time), and a structure of formula II (R5 is a 2-4C substituent having carbon-carbon double bond or carbon-carbon triple bond; p is 0-1) at the end of the resin. As this polyether resin, a resin with a structural unit of formula III (R6 to R9 are each hydrogen, fluorine, a 1-6C alkyl, a 1-6C alkenyl or the like; A is a methylene, 2,2- isopropylidene, ether, sulfone or the like) is preferably used.