METHOD FOR PRODUCING FRICTION MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide a thermoforming method for a friction material which can prevent the occurrence of defective molding such as cracks and blisters, obtain a friction material excellent in quality, and improve the productivity of the friction material by curtailing the length of time for a thermoforming process. SOLUTION: A method for producing the friction material includes the thermoforming process in which the preliminary molding of the friction material is thermoformed at a prescribed temperature under a prescribed pressure in a thermoforming mold, pressurization and pressure reduction are repeated alternately prescribed times, and gas generated from the preliminary molding is subjected to degassing treatment. The degassing treatment process includes the first pressure reduction period in which the pressure is reduced from a molding pressure to the vapor pressure of the gas generated from the preliminary molding within 1.5 s and the second pressure reduction period in which the pressure is reduced to the atmospheric pressure during a time at least twice as long as the first pressure reduction period.