Polyformal resin copolymer and method for producing the same

A polyformal resin copolymer comprising a structural unit (a) having a fluorine structure with bisphenol moieties as represented by General Formula (1) and a structural unit (b) represented by General Formula (2), wherein the proportions of the structural unit (a) and the structural unit (b) are in a range of 1:99 to 99:1 in a molar ratio:

• where, in General Formula (2), R1 and R2 are each independently a hydrocarbon group with a carbon atom number of 1 to 9 that does not contain an aromatic group or a halogen atom, p and q represent identical or different integers of 0 to 4, and W is any one of Formula (3) below:
• wherein, R3 and R4 each represent a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group with a carbon atom number of 1 to 9, an alkoxy group with a carbon atom number of 1 to 5, an aryl group with a carbon atom number of 6 to 12, an alkenyl group with a carbon atom number of 2 to 5 or an aralkyl group with a carbon atom number of 7 to 17;
• R3 and R4 may also bind to each other and form a carbocyclic ring or a heterocyclic ring;
• R5 to R8 each represent a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group with a carbon atom number of 1 to 9, an alkoxy group with a carbon atom number of 1 to 5 or an aryl group with a carbon number of 6 to 12;
• and a represents an integer of 1 to 20.