Patent ID: 8563665

Claim:
A modified dimethylnaphthalene formaldehyde resin obtained by a process comprising modifying a polyfunctional dimethylnaphthalene formaldehyde resin comprising a constituent unit represented by formula [1] in a molecule thereof with at least one selected from the group consisting of a phenol represented by formula [2], a naphthol represented by formula [3] and a naphthol represented by formula [4]: wherein at least one of the naphthol represented by formula [3] and the naphthol represented by [4] is included; and R 1 represents an alkyl group comprising from 1 to 4 carbon atoms; each of R 2 , R 3 and R 4 independently represents a hydrogen atom or an alkyl group comprising from 1 to 3 carbon atoms; A is represented by —(OCH 2 ) t —; t is from 0 to 2; x is from 0 to 4; and y represents an integer of from 0 to 2, wherein the polyfunctional dimethylnaphthalene formaldehyde resin is obtained through a condensation reaction between a dimethylnaphthalene and formaldehyde, a molar ratio of the dimethylnaphthalene to formaldehyde is from 1/2.5 to 1/6, and in the polyfunctional dimethylnaphthalene formaldehyde resin comprising a constituent unit represented by formula [1] in a molecule thereof, a mean value of the number of hydrogen atoms substituted by a reaction producing the dimethylnaphthalene formaldehyde resin, among the six hydrogen atoms directly bonded on a naphthalene ring, is from 1.5 to 3.5.