Patent ID: 7491664

Claim:
A wet friction material, comprising: a paper base material; and a binder, wherein the binder comprises a cured material of a liquid resin composition obtained by mixing: a hydrolyzed solution of a silane coupling agent represented by the following formula (1); and a resol-type phenol resin, wherein a weight ratio (S/R) between respective non-volatile components of the hydrolyzed solution (S) of the silane coupling agent and the resol-type phenol resin (R) is in a range of from 80/20 to 20/80: (X)(R 1 ) n Si(OR 2 ) 3−n (1), wherein X represents an alkylamino group having a primary amine at a terminal; R 1 and R 2 each represents an alkyl group having from 1 to 3 carbon atoms; and n represents an integer of 0 or 1; wherein the wet friction material has a positive gradient in μ-V characteristic property.