CA1112388A - Brake block material - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Low abrasion, heat resistant, high strength friction material with a high resistance wear is described as containing phenolic resin, an organic modifier, processed mineral fibers and a filler. Rubber, either natural or synthetic, graphite, a metallic oxide, a color pigment and factice may also be present. The material finds particular use in brake blocks for disc and drum brake applications on heavy duty trucks and the like. This invention is distinguishable from others by reason of the use of spun blast furnace slag fibers rather than the asbestos fibers which have generally been used in the prior art brake block materials.

Description

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(1) Field of the Invention:
This invention relates to Friction material such as used in brake blocks, drum brake linings and disc pads in vehicle braking systems.

(2) Description of the Prior Art The prior art friction materials have typically included rubber and resin binders, inorganic fillers and asbestos fibers. Glass fibers and glass strands have also been present in the prior art materials as have metal fibers.
The present invention utili~es a processed mineral Fiber formed of blast furnace slag such as known in the art as spun slag. The spun slag Ftbers in combination with the other materials used as disclosed herein result in an unusually efficent brake block material havin~ none of the disadvantages ;n manufacture or use that have been commonly associated with asbestos fibers in the past.
U.S. Patent 3,365,041 of January 23, 196E disc!oses a Fric~ion material In the form of a clutch facing which incorporates asbestos fibers and is typical oF the prior art.
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U.S. Patent 3,390,750 of July 2, 196E incorporates porous sintered metal fib2rs in a friction element, for example stainless steel fibers. --U.S. Patent 3,526,306 oF September 1, 1970 dlscloses the use oF ~13ss yarn, asbestos Fibers, and fine metal wires in a friction element comprising a clutch facing.

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U.S. Patent 3,934,686 of January 27, 1976 discloses a friction element in which random textile fibers and/or boron fibers are present.
U.S. Patent 3,956,545 of May 11, 1976 relates to a glass fiber fric tion element and U.S. Patent 3~959~194 of May 259 1976 discloses a brake shoe material incorporating cellulosic and/or asbestos fibers.
The present invention differs from the pri.or ar~: primarily in the utilization of fibers spun from blast furnace slag ancl the unusual water and heat reslstance quali.ties of the materlal resulting from thei.r use.
Summary of the Inventi.on A consistently wear and heat res.istant material capable oF safe and economic manufacture and use can be made from a composition comprising 20% to 75~ by weight oF fibers spun from blast furnace slag, 13~ to 33~ by weight phenolic resin and associated modifier such as a GRS poiymer, and 10~ to 35~ by weight barytes. Variati.ons of the inventi.on may incorporat e 3% to 8% by weight pcwdered or flaked graphite, .05~ to 3~ by wei~ht of a metallic oxide., 1% to 4% by weight of a color pigment, such as carbon black, and 3% to 9~ by weight of rubber, natural or synthetic.
Description of the Preferred Embod;ment The composition of this inventi.on is a material satisfactory for the manufacture of brake blocks, pads, and the like.as used in drum and disc brake applications on various vehi.cles and particularlY heavy duty trucks and the like. The composition oF thîs invention is a material which incorporates processed mineral fibers whlch are spun From blast -Furnace slaq and these fibers, which in a typical example of the invention will ~-be present in an amount approxima~ely 30~ by weight, combine readily in : ~ the mixing and manufacturing process wtth phenolic resin 14~ by weight and ; an organic modifier for the resin, such as a GRS or HYCAR (TM~ polymer, an acrylonitrile~ 13% by wetght, 5~ by weight of a metallic oxide, ferrous or non-ferrous, a filler 27~ by weight such as barytes (barium sulphate), 5~ by weight of a powdered or flaked graphite : -3~

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and 3% by weight of a color pigment such as carbon black.
Additiooal modifiers can include other polymers such as natural rubber, styrene-butadine and butyl rubbers, and vegetable oils such as linseed, china wood and cashew oils.
A batch of the material is thoroughly mi~ed and performed under pressure to a desired shape with the formed shapes being positioned in a hydraulic molding press and subjected to 2~000 PSI pressure at a temperature of between Z85F. to 350t1F. for a suitable time, such as ten minutes. Tl1e cured shapes are removed to an oven for post cure at a temperature of between 300F. and 350F. for a t;me of approximately 18 hours.
Those skilled in the art will observe that the quantities of the ingredients in the composition of the material may vary considerably, for example the spun blast furnace slag fibers may be present in quantities between 20~ and 75~, by weight, a total of the phenolic resin and its organic modifiers may be present in amounts between 13~ and 33~ by weight, the filler barytes may be present in amo-ln-ts between 15% and 35~ by weight, the metallic oxides may be present in amounts between ~% and 6~ by weight, the graphite may be present in amounts between 3% a 8~ by weight, and factice may be present in amounts between 4% and 8~ by weight. In addition - ~0 to or in place of the carbon black pigment~ zinc oxide may be used and the rubber, when present, acts as a binder and may be natural or synthetic or elastomeric material, which can be vulcanized or otherwise cured. ~Ihen synthetic the rubber can be butyl, styrene-butadiene, or nitrile.
Tllose skilled in the art will recognize that the difficulties hereto-fore encountered in manufacturing brake block material incorporating asbestos fibers are overcome completely through the use of the composition of this invention. The spun blast furnace slag fibers are not readily airborne and under such circumstances as they may become airborne they do not comprise health hazards to manufacturing personnel. i1Ore importantly the spun blas-t furance slag fibers in the composition result in a ~li-Although but two embodiments of the present invent;on have been described, it will be apparent to thos~ sk.illed in th~ art that various changes and modific3tions may be made there;n without departin~ ~ro~

4 the spirit o~ the invention.

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Claims (11)

The embodiments of the invention in which an exclusive property of privilge is claimed are defined as follows:

1. An improved heat and water resistant friction material comprising in approximate percent by weight:
Spun blast furnace slag fibers...............................20% - 75%
Phenolic resin and modifier from the group consisting of vegetable oils and polymers......................................13% - 33%
Barytes......................................................10% - 35%,

2. The improved heat and wear resistant friction material of Claim 1 wherein said modifier is organic and one of the group consisting of vegetable oils.

3. The improved heat and wear resistant Friction material of Claim 1 and wherein said modifier is a polymer of the group consisting of natural rubber,styrene-butadiene, acrylonitrile and butyl rubbers.

4. The improved heat and war resistant Friction material of Claim 1 and wherein said modifier is GRS polymer.

5. The improved heat and wear resistant friction material of Claim 1 and wherein said modifier is acrylonitrile.

6. The improved heat and wear resistant friction material of Claim 1 and wherein rubber in approximate percent by weight between 3% to 9% is included.

7. An improved heat and wear resistant friction material comprising in approximate percent by weight:
Spun blast furnace slag fibers...............................20% - 75%
Phenolic resin and modifier from the group consisting of vegetable oils and polymers......................................13% - 33%
Barytes......................................................10% - 35%
Graphite..................................................... 3% - 8%
Carbon Black................................................. 1% - 4%
Metallic Oxide............................................... 2% - 6%

8. An improved heat and wear resistant friction material comprising in approximate percent by weight:
Spun blast furnace slag fibers.................................. 75%
Phenolic resin and modifier from the group consisting of vegetable oils and polymers.......................................... 15%
Barytes......................................................... 10%

9. An improved heat and wear resistant friction material comprising in approximate percent by weight:
Spun blast furnace slag fibers.................................. 30%
Phenolic Resin.................................................. 14%
Organic modifier for the resin from the group consisting of vegetable oils and polymers.......................................... 13%
Barytes......................................................... 25%
Factice......................................................... 7%
Graphite........................................................ 5%
Carbon Black ................................................... 3%
Metallic Oxide.................................................. 3%

10. An improved heat and wear resistant friction material comprising in approximate percent by weight:
Spun blast furnace slag fibers.................................. 37%
Phenolic Resin.................................................. 14%
Organic modifier for the resin from the group consisting of vegetable oils................................................................. 13%
Barytes ........................................................ 25%
Factice......................................................... 7%
Graphite................................................... ,... 5%
Carbon Black.................................................... 3%
Metallic Oxide.................................................. 3%

11. An improved heat and wear resistant friction material comprising in approximate percent by weight;
Spun blast furnace slag fibers.............................. 20% - 75%
Phenolic resin and modifier from the group consisting of natural rubber, styrene-butadiene, acrylonitrile and butyle rubbers 13% - 33%
Barytes..................................................... 10% - 35%
Factice..................................................... 4% - 8%
Graphite.................................................... 3% - 8%
Carbon Black................................................ 1% - 4%
Metallic Oxide.............................................. 2% - 6%