Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D69/00—Friction linings; Attachment thereof; Selection of coacting friction substances or surfaces
  • F16D69/02—Composition of linings ; Methods of manufacturing
  • F16D69/025—Compositions based on an organic binder
  • F16D69/026—Compositions based on an organic binder containing fibres
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K7/00—Use of ingredients characterised by shape
  • C08K7/02—Fibres or whiskers
  • C08K7/04—Fibres or whiskers inorganic
  • C08K7/06—Elements

Definitions

• This invention relates to friction materials, and more particularly to friction materials of the kind used for brake pads, brake linings, clutch facings and similar uses.
• Friction materials of this kind are generally composed of a thermoset binder, an inorganic fibrous reinforcement and various fillers and other additives. These compositions are required to withstand severe operating temperatures and pressures under repeated application without failure or deterioration in friction properties'and the fibrous reinforcement generally used is asbestos. Numerous proposals have been made of compositions containing other inorganic fibrous reinforcement but such materials have so far had limited commercial acceptance.
• a friction material comprises a thermoset binder, a fibrous reinforcement, and other fillers and additives, the thermoset binder comprising a phenol-formaldehyde resin and making up 20 to 45 per cent by volume of the material, the fibrous reinforcement consisting solely of short lengths of steel fibre in an amount between 5 and 15 per cent by volume, and at least 10 per cent by volume of the material comprising an inert mineral filler.
• inert mineral filler in this specification we mean a particulate filler whose presence does not substantially affect the friction properties of the material and which is an inexpensive mineral such as barytes, whiting or silica. We exclude metal oxides from this class of fillers since they are used for other purposes in friction materials.
• the fibrous reinforcement preferably consists of fine steel fibres having a length of the order of 1 to 5mm and a diameter of the order of 0.125mm.
• the steel may be a mild steel.
• the fibrous reinforcement preferably constitutes at least 9% by volume of the friction material.
• the thermoset binder includes a thermoset resin based on a phenol-formaldehyde material but may also include a heat and chemical resistant vulcanized rubber, such as a nitrile rubber.
• a mixture of such materials is used in which the phenol-formaldehyde resin material is preferably the major constituent i.e. more than 50% of said mixture.
• a rubber When a rubber is used it may be incorporated into the friction material in the form of a solution in an organic solvent such as trichloroethylene-, or in the form of a powder, and a vulcanizing, agent such as sulphur can be also used.
• friction materials It is usual in the manufacture of friction materials to include various other material as friction and wear modifiers the proportions of which can be varied to adjust to the friction and other properties of the materials.
• friction and wear modifiers are carbon, graphite, antimony trisulphide and molybdenum disulphide and metals in a finely divided form.
• suitable metals are copper, brass and tin. A mixture of such materials may be used, and the total amount of such materials may be up to 40 per cent by volume.
• the friction materials of the present invention are particularly suited to be manufactured by a press- moulding technique in which all the ingredients of the material are compounded together, the compounded mix disintegrated and (optionally) dried and then moulded into a component such as a brake pad in a die under pressure. The moulded component is then removed from the die and baked to cure the binder.
• the invention provides friction materials which contain no asbestos and yet which have friction properties comparible to conventional asbestos-reinforced materials.
• Sample disc brake pads were made using the formulation given below in Table I. The ingredients were compounded together the nitrile rubber being introduced as a powder and the resulting dry mix was disintegrated and press-moulded in a die into the shape of disc-brake pads. The mouldings so produced were baked in an oven to cure the binder.
• sample disc-brake pads were tested and their friction properties found to be comparable to materials containing asbestos as the fibre reinforcement.
• This example illustrates a formulation with a higher loading of steel fibres.
• Disc brake pads were manufactured to the formulation given below in Table II by the same method as used in Example 1 except that the nitrile rubber in the present example was introduced as a 16% (by weight) solution in trichloroethylene.
• This example illustrates the use of a lower binder content and higher loading of inert filler (Barytes).
• Disc brake pads were made by the same method as Example 2 to the formulation given in Table III.
• the assembly shear strengths measured were 2210 and 1890 psi.
• This example illustrates the use of an even lower binder content at the same loading of barytes.
• Disc brake pads were made as in Example 2 to the formulation given in Table IV.
• the assembly shear strengths measured were 1360 and 1150 psi.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Braking Arrangements (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)

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Publications (2)

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ID=10353584

Family Applications (1)

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Cited By (8)

Families Citing this family (16)

Citations (4)

Family Cites Families (2)

• 1977
  • 1977-08-10 GB GB33485/77A patent/GB1604828A/en not_active Expired
• 1978
  • 1978-07-31 US US05/929,533 patent/US4226759A/en not_active Expired - Lifetime
  • 1978-08-01 IN IN567/DEL/78A patent/IN148771B/en unknown
  • 1978-08-02 ZA ZA00784380A patent/ZA784380B/xx unknown
  • 1978-08-08 DE DE7878300260T patent/DE2860882D1/de not_active Expired
  • 1978-08-08 EP EP78300260A patent/EP0000841B1/de not_active Expired
  • 1978-08-09 BR BR7805106A patent/BR7805106A/pt unknown
  • 1978-08-09 AU AU38756/78A patent/AU3875678A/en active Pending
  • 1978-08-09 IT IT50667/78A patent/IT1157152B/it active
  • 1978-08-10 CS CS785245A patent/CS216921B2/cs unknown
  • 1978-08-10 JP JP9774978A patent/JPS5434351A/ja active Pending
  • 1978-08-10 SU SU782649255A patent/SU890983A3/ru active
  • 1978-08-10 DD DD78207210A patent/DD138220A5/de unknown

Patent Citations (4)

Non-Patent Citations (1)

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