Friction material having heat-resistant paper support bearing resin-bonded carbon particles

• US 5,083,650 A
• Filed: 05/24/1991
• Issued: 01/28/1992
• Est. Priority Date: 05/24/1991
• Status: Expired due to Term

• Current Assignee: 3M Company, General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: 3M Company, General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Seiz, David S., Eldridge, Larry
• Primary Examiner(s): BONCK, RODNEY H
• Application Number:
  US07/705,182
• Time in Patent Office: 249 Days
• Field of Search: 192/107 M, 188/251 A, 427/203, 427/326, 428/283, 523/155, 523/156
• US Class Current: 192/107.00M
• CPC Class Codes: F16D 69/02 Composition of linings ; Methods of manufacturing
• CPC Class Codes: F16D 69/025 Compositions based on an organic binder

Abstract

A friction member which is suitable for use as a friction facing member in a transmission is provided. the friction member includes a uniform density heat resistant paper, a first layer of thermoset polymeric binder coated over and at least partially impregnated into one major surface of the paper, granular carbon friction particles uniformly distributed over and partially imbedded in the exposed surface of the first layer and a second layer of thermoset binder over the first layer and partially imbedded granular friction particles which coats without obscuring the granular friction particles. The friction member is made by applying a coating if liquid thermosettable binder filled with carbon particles to one major surface of the paper, supporting the coated paper and a movable carrier, applying a uniform layer of carbon friction particles over the binder layer, at least partially curing the binder layer, applying a second coating of thermosettable binder material over the carbon particles and curing the coatings until the binder material is thermoset.

Claims

1. A friction member which is especially useful as a friction facing member in a transmission, said friction member comprising:

(a) a uniform density heat resistant paper;

(b) a first layer of thermoset polymeric binder coated over and at least partially impregnated into one major surface of the paper;

(c) granular carbon friction particles uniformly distributed over and partially embedded in the exposed surface of the first layer; and

(d) a second layer polymeric binder as defined in (b) over the first layer and the partially embedded granular carbon friction particles which coats without obscuring the granular carbon friction particles.

2. The friction member of claim 1 wherein said paper has a weight 40 to 60 g/m².

3. The friction member of claim 1 wherein said heat resistant paper is formed substantially of resin bonded aramid staple fibers.

4. The friction member of claim 3 wherein said aramid staple fibers have a length between 0.6 and 2 cm.

5. The friction member of claim 3 wherein said resin is an acrylate resin.

6. The friction member of claim 1 wherein said thermoset polymer is an acid-catalyzed phenolic resin.

7. The friction member of claim 1 wherein said first layer of thermoset polymeric binder is filled with carbon filler particles.

8. The friction member of claim 7 wherein said carbon filler particles are of a size less than 50 μ

m.

9. The friction member of claim 1 wherein at least 85% by weight of said carbon friction particles have an average particle size which exceeds about 40 μ

m and no more than about 10% by weight have an average particle size which exceeds 250 μ

m.

10. The friction member of claim 1 wherein at least 85% by weight of said carbon friction particles have an average particle size which exceeds about 40 μ

m and no more than about 10% by weight have an average particle size which exceeds 350 μ

m.

11. Method of making a friction member, said method comprising the steps of:

(a) applying a coating of a liquid coating composition comprising thermosettable binder material filled with carbon filler particles to one major surface of a continuous length of uniform density, heat resistant paper under viscosity conditions which cause the coating composition to coat and impregnate the coated surface of the paper;

(b) supporting the coated paper on a movable carrier;

(c) applying a uniform layer of granular carbon friction particles over the coating of step (a) while the coating is sufficiently uncured so that at least some of the granular carbon friction particles become partially embedded into the coating;

(d) at least partially curing the coating after application of the granular carbon friction particles;

(e) applying a coating of a coating composition as defined in (a) over the partially cured coating; and

(f) curing the coatings until the binder material is thermoset.

12. A transmission which includes a friction facing member to transmit torque to another member by contact therewith, said friction facing member comprising:

(a) a uniform density heat resistant paper;

(b) a first layer of thermoset polymeric binder coated over and at least partially impregnated into one major surface of the paper;

(c) granular carbon friction particles uniformly distributed over and partially embedded in the exposed surface of the first layer; and

(d) a second layer polymeric binder as defined in (b) over the first layer and the partially embedded granular carbon friction particles which coats without obscuring the granular carbon friction particles.