Asbestos-free friction materials

DETAILED DESCRIPTION We claim: 1.
An asbestos-free friction material having good friction stability and wear properties consisting essentially of an aromatic polyamide fiber, a binder, from about 3 to about 15 parts of antimony sulfide and from about 7 to about 30 parts of copper oxide.
2.
The friction material of claim 1 wherein the binder is a mixture of two or more binders.
3.
The friction material of claim 2 wherein one of the binders is a phenolic resin.
4.
The friction material of claim 2 wherein the binder is a combination of phenolic resin and a copolymer of butadiene and acrylonitrile.
5.
An asbestos-free friction material having good friction stability and wear properties consisting essentially of a mixture of glass fiber and an aromatic polyamide fiber, a phenolic resin, from about 1.
5 to about 12 parts of antimony sulfide and from about 10 to about 25 parts of copper oxide.
6.
The friction material of claim 1 wherein it contains also from about 2% to about 15% of barytes.
7.
The friction material of claim 5 wherein it contains also from about 2% to about 15% of barytes.




Description:
This invention relates as indicated to asbestos-free friction materials.
More particularly, it relates to such materials as are especially adapted for use in brake and clutch linings.
Still more particularly, it relates to the use of these materials in dry, pad-type clutch linings.
BACKGROUND OF THE INVENTION It is well-known that friction materials which are intended for use in heavy duty brake or clutch operations in motor vehicles must withstand severe service conditions.
In use they are subjected to vigorous treatment by repeated and prolonged braking or clutching applications which develop high temperatures, usually above 500.
degree.
F.
, in the friction materials, these temperatures sometimes exceeding 1000.
degree.
F.
on the friction surface of the material and progressively decreasing inwardly of such surface.
These high temperatures, especially when occurring during high speed stops or following repeated applications of the brakes or clutches, tend to decompose the organic materials which act as a binder in the friction material