Patent ID: 8648152

Claim:
A polyfunctional dimethylnaphthalene formaldehyde resin obtained by allowing (1) at least one dimethylnaphthalene having one methyl group on each of two benzene rings in a naphthalene ring thereof and selected from the group consisting of 1,5- dimethylnaphthalene, 1,6-dimethylnaphthalene, 1,7- dimethylnaphthalene, 1,8-dimethylnaphthalene and 2,7-dimethylnaphthalene; and (2) formaldehyde to react with each other in the presence of water and an acid catalyst, the polyfunctional dimethylnaphthalene formaldehyde resin having a mean value of the number of hydrogen atoms substituted by the reaction among the six hydrogen atoms directly bonded on the naphthalene ring in the dimethylnaphthalene of from 1.8 to 3.5.