Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L61/00—Compositions of condensation polymers of aldehydes or ketones; Compositions of derivatives of such polymers
  • C08L61/04—Condensation polymers of aldehydes or ketones with phenols only
  • C08L61/06—Condensation polymers of aldehydes or ketones with phenols only of aldehydes with phenols
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L15/00—Compositions of rubber derivatives
  • C08L15/005—Hydrogenated nitrile rubber
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
  • C08L83/04—Polysiloxanes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
  • C08L9/02—Copolymers with acrylonitrile
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
  • C08L9/02—Copolymers with acrylonitrile
  • C08L9/04—Latex
• • 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
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L61/00—Compositions of condensation polymers of aldehydes or ketones; Compositions of derivatives of such polymers
  • C08L61/20—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen
  • C08L61/26—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with heterocyclic compounds
  • C08L61/28—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with heterocyclic compounds with melamine

Definitions

• compositions based on silicone resin compositions based on silicone resin, methods for obtaining them and their applications
• the present invention relates to silicone resin compositions, processes for making them and their applications as a friction material, in particular their use in friction rings for clutch friction discs or brake pads.
• a friction ring is generally made from at least one wire providing resistance to centrifugal force and a binder (also called cement) providing cohesion.
• Most binders are made from phenolic and / or melamine organic resins. These binders have good thermal stability.
• the recent evolutions in the immediate environment of the binder (reduction of the thermal masses in the double damping flywheels and clutches with catch-up of wear, increase of the powers and energy, etc.) gave rise to the need for binders to higher thermal resistance.
• silicone resins that the introduction of silicone resin in a binder comprising a phenolic resin, increases the thermal resistance of said binder.
• silicone resins this document is aimed at silicone elastomers.
• fluids, elastomers and resins there are three major families of silicones: fluids, elastomers and resins, the latter two families being chemically distinct.
• the combination of a phenolic resin with a silicone elastomer described in this application does not make it possible to obtain a binder having an acceptable coefficient of friction beyond a temperature of 350 ° C.
• the work of the inventors has identified a composition capable of being used as a binder, said binder having an improved holding of the friction coefficient with the temperature, particularly above 350 0 C.
• the present invention therefore aims at a composition comprising: 3 to 30% by weight of silicone resin, preferably 5 to 15%,
• silicone resin also called “polysiloxane resin” means thermosetting silicone resins having a three-dimensional network with a high degree of crosslinking. They are in general of formula R n SiXmOy, in which - R, identical or different, represents a methyl or a phenyl,
• X identical or different, represents a hydrogen, a chlorine, a hydroxy, a methoxy or a phenyloxy, y, n and m such that the molecule reaches a molecular mass of the order of 2000 to 6000.
• These resins have a temperature of glass transition above ambient temperature (18-21 ° C.).
• silicone resins of the polymethylsiloxane, polyphenylmethylsiloxane and / or polyphenylsiloxane type are particularly advantageous for silicone resins of the polymethylsiloxane, polyphenylmethylsiloxane and / or polyphenylsiloxane type.
• NBR refers to "Nitrile Butadiene Rubber”. NBR derivatives are carboxylated NBR (XNBR), hydrogenated NBR (HNBR). By “NBR and / or its derivatives”, each of these compounds is targeted individually or as a mixture.
• the composition according to the invention may comprise at least one other resin, the percentage by total weight of all the resins present in the composition being from 10 to 50%, preferably 15 to 30%.
• This at least one other resin may be chosen from the group consisting of melamine formaldehyde resins, phenolic resins (novalaque resins, resole resins), resorcinols resins, epoxy resins, and the like.
• the introduction of a melamine or phenolic resin into the composition is then advantageously carried out at a weight percentage of 5 to 30% and from 0 to 20%, respectively, relative to the total weight of the composition.
• the percentages by weight of melamine or phenolic resin are 10 to 20% and 0 to 10% respectively.
• a melamine resin is present without the presence of phenolic resin.
• the composition according to the invention may comprise 10 to 40% by weight of at least one filler. It is more particularly friction loads such as barium sulfate or carbon black.
• the composition may further comprise at least one surfactant and / or an adjuvant.
• surfactant is more particularly targeted polyvinylalcohol (PVA) and anionic surfactants such as phosphates, polyphosphates, pyrophosphates, sulfates, sulphonates or carboxylates, associated with a cation (sodium, potassium, ammonium, calcium) or amines) and mixtures thereof.
• PVA polyvinylalcohol
• anionic surfactant is sodium polyphosphate and / or PVA.
• the use of PVA is particularly recommended in the case of a binder comprising both NBR, and / or its derivatives mixed with a phenolic resin.
• the term "adjuvant” refers essentially to additives known as "manufacturability" such as catalysts (such as sulfur, particularly advantageous in the case where NBR is used), thickeners (cellulose or its derivatives), improvers adhesion (rosin, petroleum resin).
• the composition according to the invention may also comprise at least one yarn, preferably a yarn mixture comprising at least one textured glass yarn, a metal yarn and a yarn based on mineral and / or organic fibers.
• Such a composition in particular when there is presence of fillers, is particularly suitable for the manufacture of a friction ring for friction clutch disc of the dry friction type.
• the textured glass yarn is 600 to 5000 tex.
• the wire is advantageously a copper wire.
• the mineral and / or organic fibers are preferably glass fibers or polyacrylonitrile or derived fibers.
• the invention also relates to the processes for preparing the compositions described above.
• the invention thus proposes a first process for preparing a composition according to the invention, comprising the following steps:
• the process for preparing a composition according to the invention may comprise the following steps: -AT-
• premix comprising the resin (s) and filler (s), optionally the surfactant (s) and / or adjuvant (s) and water, and
• the process for preparing this composition may comprise the following steps:
• composition further comprising at least one yarn is particularly preferred according to the invention, and it is produced by impregnating the yarn (s) with any one of the compositions obtained according to the three preparation methods according to the invention. described above.
• compositions according to the invention are also within the scope of the invention. It is more particularly the use of a composition according to the invention for the manufacture of a friction material, in particular for the manufacture of a clutch lining. These compositions are particularly suitable for producing friction rings for clutch friction discs working dry and that of brake pads.
• the invention also relates to a friction material, such as a friction ring for clutch friction disc working dry or brake pad, comprising the composition according to the invention described above.
• FIG. 1 represents the evolution of the coefficient of friction with temperature for compositions with or without siloxane resin
• FIG. 2 represents the evolution of the coefficient of friction with temperature for compositions comprising or not NBR
• FIG. 3 represents the evolution of the coefficient of friction with temperature for compositions comprising or comprising no polymethylphenylsiloxane resin and NBR
• FIG. 4 represents the evolution of the coefficient of friction with temperature for compositions comprising or not polymethylsiloxane and NBR resin.
• Example 1 Example of Composition According to the Invention
• the percentages are given as a percentage by weight relative to the total weight of the composition.
• Example 2 Process for preparing a friction ring
• the mixture is produced in aqueous phase.
• Polysiloxane resin and any other resins are incorporated as powders in an aqueous mixture containing the NBR rubber latex and the other fillers or constituents of the mixture (dispersions).
• the water content is adjusted to have a viscosity of 8 to 18 poles.
• the solids content of the mixtures vary from 50 to 90%.
• thickeners may be added at a level of from 0.1 to 5% by weight of the mixture (for example, 0.3% of hydroxyethylcellulose) or from 0.1 to 1% by weight of the surfactants.
• mixture for example, 0.3% sodium polyphosphates, potassium oleate
• improvers adhesion at a level of 0.1 to 5% by weight of the mixture (for example, 1, 5 or 3% rosin).
• a continuous wire composed of several types of fibers such as glass, polyacrylonitrile (PAN) and copper is then impregnated and dried.
• the water is evaporated to a relative humidity (RH) of 0.5 to 3%.
• the crowns are then formed into lobing.
• the following steps are thermocompression at 170-200 ° C. at 0.5 to 40 MPa and deburring of the crowns.
• the post-baking step ranges from 2 to 6 hours, at temperatures ranging from 200 to 330 ° C., continuously or in stages. This step can also be omitted if no phenolic resin is present in the composition.
• compositions are designated as follows: "Formula X (type of resin + type of rubber)".
• Formula 1 when it comprises phenolic resin and SBR, corresponds exactly to the reference formula, formula 2 being a variant of this formula (identical to formula 1 with the exception of the absence of copper).
• NBR or SBR NBR or SBR
• EXAMPLE 3 Evolution of the coefficient of friction with temperature, in start-up simulation, for compositions with or without siloxane resin.
• compositions are similar to the reference composition with one modification: the composition "formula 1 (PMS + SBR)" comprises a polymethylsiloxane resin replacing the phenolic resin contained in the reference composition,
• composition "Formula 1 (PMPS + SBR)" comprises a polymethylphenylsiloxane resin to replace the phenolic resin contained in the reference composition.
• compositions are compared in the context of a hill start test, aimed at determining the evolution of the coefficient of friction as a function of temperature.
• the test aims to follow the evolution of the coefficient of friction with the temperature.
• the measurement is made in a clutch on a brake bench.
• Figure 1 are indicated: a continuous thick line representing the minimum permissible coefficient of friction.
• a continuous fine curve representing the coefficient of friction of the reference composition
• a regular dashed curve representing the coefficient of friction of the composition "formula 1 (PMS + SBR)”
• - an irregular dashed curve representing the coefficient of friction of the composition "Formula 1 (PMPS + SBR)”.
• compositions comprising siloxane resins have a much better resistance to the coefficient of friction at temperature.
• EXAMPLE 4 Evolution of the coefficient of friction with temperature, in start-up simulation, for compositions comprising NBR or SBR.
• This example is intended to compare two compositions based on phenolic resins, of a formulation substantially similar to that of the reference composition, comprising NBR ("Formula 2 (phenolic + NBR)") or SBR.
• EXAMPLE 5 Evolution of the coefficient of friction with temperature, in hill start simulation, for compositions comprising polymethylphenylsiloxane type silicone resin coupled to NBR or SBR, in comparison with the reference composition.
• EXAMPLE 6 Evolution of the coefficient of friction with temperature, in start-up simulation, for compositions comprising polysiloxane-type silicone resin with NBR or SBR, in comparison with the reference composition.
• composition designated under the name "Formula 1 (phenolic + SBR)" corresponds to the reference composition described in Example 3.

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• Chemical & Material Sciences (AREA)
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• Chemical Kinetics & Catalysis (AREA)
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• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
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• Compositions Of Macromolecular Compounds (AREA)

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• 2008
  • 2008-04-16 FR FR0852569A patent/FR2930254B1/fr active Active
• 2009
  • 2009-04-15 DE DE112009000893.3T patent/DE112009000893B4/de active Active
  • 2009-04-15 WO PCT/FR2009/050693 patent/WO2009138618A2/fr active Application Filing

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