Slurry composition and method for forming friction material therefrom

A slurry composition for a wet slurry processed friction material, comprising water and 20-40% by weight solids, the solids comprising:

• 2-15 vol. % organic fibers of 2-15 mm length;
• 5-10 vol. % organic pulp of ¼-4 mm length;
• 2-10 vol. % inorganic fibers of 2-15 mm length;
• 2-15 vol. % metallic fibers of 2-15 mm length;
• 2-10 vol. % inorganic flake materials of ½-10 mm in the largest dimension;
• 5-20 vol. % carbonaceous particles of ½-10 mm in the largest dimension;
• 12-25 vol. % resin binder;
• and
• the balance being at least one filler selected from the group consisting of potassium titanates, zirconium silicate, zirconia, barium sulphate, calcium carbonate, rubber particles and cashew particles.

A method of forming a molded friction material, comprising:

• placing a slurry composition in a die cavity, the slurry composition comprising water and 10-50% by weight solids, the solids comprising 2-15 vol. % organic fibers of 2-15 mm length, 2-20 vol. % organic pulp of up to 8 mm length, 2-10 vol. % inorganic fibers of 2-15 mm length, 2-15 vol. % metallic fibers of 2-15 mm length, 2-10 vol. % inorganic flake materials of ½-10 mm in the largest dimension, 5-20 vol. % carbonaceous particles of ½-10 mm in the largest dimension, and resin binder;
• extracting the water from the slurry by pressing on the slurry in the die cavity with a die punch sized to form a gap between the punch and a sidewall of the die cavity whereby the water is extracted through the gap, followed by drying, resulting in the formation of a friction material preform;
• and
• molding the friction material preform by applying heat and pressure thereto.