Wet friction material
The wet friction material of the present invention is obtained by impregnating a friction base material with a bonding resin composition comprising a resol phenolic resin and a maleinized drying oil and curing the resulting material. The maleinized drying oil is obtained by reacting a drying oil such as tung oil or linseed oil with anhydrous maleic acid. The content thereof is preferably 50 to 250 parts by weight, based on 100 parts by weight of the resol phenolic resin. The wet friction material of the present invention has a high static friction coefficient and excellent durability.
1. A wet friction material obtained by impregnating a friction base material with a bonding resin composition comprising a resol phenolic resin and a maleinized drying oil and curing the resulting material.
2. The wet friction material according to claim 1 , wherein the resol phenolic resin is a resol phenolic resin reacted with an unmaleinized drying oil.
3. The wet friction material according to claim 1 , wherein the maleinization ratio of the maleinized drying oil is 10 to 50 mol %, and wherein the maleinization ratio represents the reaction ratio of anhydrous maleic acid with double bonds present in an unmaleinized drying oil.
4. The wet friction material according to claim 1 , wherein the amount of the maleinized drying oil in the bonding resin composition is 50 to 250 parts by weight, based on 100 parts by weight of the resol phenolic resin.