EP1601540A1 - Lubricating composition for a tyre safety support - Google Patents

Lubricating composition for a tyre safety support

Info

Publication number
EP1601540A1
EP1601540A1 EP04707202A EP04707202A EP1601540A1 EP 1601540 A1 EP1601540 A1 EP 1601540A1 EP 04707202 A EP04707202 A EP 04707202A EP 04707202 A EP04707202 A EP 04707202A EP 1601540 A1 EP1601540 A1 EP 1601540A1
Authority
EP
European Patent Office
Prior art keywords
composition according
polyoxyalkene
lubricating
silica
composition
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP04707202A
Other languages
German (de)
French (fr)
Inventor
Jean-Louis Mauclin
Georges Salaun
Laure Simonot
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Compagnie Generale des Etablissements Michelin SCA
Michelin Recherche et Technique SA France
Original Assignee
Michelin Recherche et Technique SA Switzerland
Michelin Recherche et Technique SA France
Societe de Technologie Michelin SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Michelin Recherche et Technique SA Switzerland, Michelin Recherche et Technique SA France, Societe de Technologie Michelin SAS filed Critical Michelin Recherche et Technique SA Switzerland
Publication of EP1601540A1 publication Critical patent/EP1601540A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C17/00—Tyres characterised by means enabling restricted operation in damaged or deflated condition; Accessories therefor
    • B60C17/10—Internal lubrication
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M107/00—Lubricating compositions characterised by the base-material being a macromolecular compound
    • C10M107/20—Lubricating compositions characterised by the base-material being a macromolecular compound containing oxygen
    • C10M107/30—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • C10M107/32—Condensation polymers of aldehydes or ketones; Polyesters; Polyethers
    • C10M107/34—Polyoxyalkylenes
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M113/00—Lubricating compositions characterised by the thickening agent being an inorganic material
    • C10M113/12—Silica
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M169/00—Lubricating compositions characterised by containing as components a mixture of at least two types of ingredient selected from base-materials, thickeners or additives, covered by the preceding groups, each of these compounds being essential
    • C10M169/02—Mixtures of base-materials and thickeners
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2201/00—Inorganic compounds or elements as ingredients in lubricant compositions
    • C10M2201/10—Compounds containing silicon
    • C10M2201/105—Silica
    • C10M2201/1056—Silica used as thickening agents
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2209/00—Organic macromolecular compounds containing oxygen as ingredients in lubricant compositions
    • C10M2209/10—Macromolecular compoundss obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • C10M2209/103—Polyethers, i.e. containing di- or higher polyoxyalkylene groups
    • C10M2209/1033—Polyethers, i.e. containing di- or higher polyoxyalkylene groups used as base material
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2209/00—Organic macromolecular compounds containing oxygen as ingredients in lubricant compositions
    • C10M2209/10—Macromolecular compoundss obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • C10M2209/103—Polyethers, i.e. containing di- or higher polyoxyalkylene groups
    • C10M2209/104—Polyethers, i.e. containing di- or higher polyoxyalkylene groups of alkylene oxides containing two carbon atoms only
    • C10M2209/1045—Polyethers, i.e. containing di- or higher polyoxyalkylene groups of alkylene oxides containing two carbon atoms only used as base material
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2209/00—Organic macromolecular compounds containing oxygen as ingredients in lubricant compositions
    • C10M2209/10—Macromolecular compoundss obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • C10M2209/103—Polyethers, i.e. containing di- or higher polyoxyalkylene groups
    • C10M2209/105—Polyethers, i.e. containing di- or higher polyoxyalkylene groups of alkylene oxides containing three carbon atoms only
    • C10M2209/1055—Polyethers, i.e. containing di- or higher polyoxyalkylene groups of alkylene oxides containing three carbon atoms only used as base material
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2209/00—Organic macromolecular compounds containing oxygen as ingredients in lubricant compositions
    • C10M2209/10—Macromolecular compoundss obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • C10M2209/103—Polyethers, i.e. containing di- or higher polyoxyalkylene groups
    • C10M2209/106—Polyethers, i.e. containing di- or higher polyoxyalkylene groups of alkylene oxides containing four carbon atoms only
    • C10M2209/1065—Polyethers, i.e. containing di- or higher polyoxyalkylene groups of alkylene oxides containing four carbon atoms only used as base material
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2209/00—Organic macromolecular compounds containing oxygen as ingredients in lubricant compositions
    • C10M2209/10—Macromolecular compoundss obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • C10M2209/103—Polyethers, i.e. containing di- or higher polyoxyalkylene groups
    • C10M2209/107—Polyethers, i.e. containing di- or higher polyoxyalkylene groups of two or more specified different alkylene oxides covered by groups C10M2209/104 - C10M2209/106
    • C10M2209/1075—Polyethers, i.e. containing di- or higher polyoxyalkylene groups of two or more specified different alkylene oxides covered by groups C10M2209/104 - C10M2209/106 used as base material
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2020/00—Specified physical or chemical properties or characteristics, i.e. function, of component of lubricating compositions
    • C10N2020/01—Physico-chemical properties
    • C10N2020/02—Viscosity; Viscosity index
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2020/00—Specified physical or chemical properties or characteristics, i.e. function, of component of lubricating compositions
    • C10N2020/01—Physico-chemical properties
    • C10N2020/04—Molecular weight; Molecular weight distribution
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
    • C10N2030/06—Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2050/00—Form in which the lubricant is applied to the material being lubricated
    • C10N2050/10—Semi-solids; greasy

Definitions

  • the present invention relates to a lubricating composition which can be used to lubricate an interface between a tire casing and a safety support mounted on a wheel rim inside said casing, such casing and a mounted assembly for a motor vehicle provided with said composition lubricating.
  • the invention also relates to lubrication between the support and the casing when running flat, following a drop in inflation pressure inside said casing.
  • envelope / envelope or rim / envelope lubricant compositions comprise, in a known manner:
  • a lubricating agent such as for example a polymer of alkene oxide (or polyoxyalkene) or glycerin; a thickening agent, such as silica, intended to increase the viscosity of the lubricating agent so as to minimize the flow of said lubricating agent due to gravity when the vehicle is at rest or is rolling with its tire casings swollen state; one or more volatile liquids which are vaporizable during a run-flat, such as water, an alcohol or a salt in aqueous solution; and a surfactant reinforcing agent also in aqueous solution.
  • a lubricating agent such as for example a polymer of alkene oxide (or polyoxyalkene) or glycerin
  • a thickening agent such as silica, intended to increase the viscosity of the lubricating agent so as to minimize the flow of said lubricating agent due to gravity when the vehicle is at rest or is rolling with its tire casings s
  • patent document FR-A-2 293 486 (or US 4,051,884) which has a lubricating composition intended to lubricate the envelope / envelope or envelope / wheel interface, which comprises a lubricating agent, an agent thickener, a volatile liquid and a surfactant reinforcing agent.
  • the lubricant of this composition consists of a polyoxyalkene, preferably a copolymer of ethylene oxide and propylene oxide.
  • the thickening agent used is a finely divided silica whose mass fraction in the lubricating composition must imperatively be at least 7.5%, this mass fraction varying from 8.4% to . 9.0% in the example embodiments.
  • This lubricating agent also comprises water as a volatile liquid intended to lower the relatively high viscosity of this copolymer.
  • the surfactant reinforcing agent consists of an ionic salt of an alkali metal of pH between 5.5 and 8.5 in aqueous solution. Mention may also be made of US-A-3,946,783 which has a lubricating composition intended to lubricate the casing / wheel interface.
  • This composition comprises, on the one hand, non-volatile agents which are intended to be housed inside the envelope and which comprise any known lubricating agent (such as water, oils, esters, silanes, surfactants , polyoxyalkene glycols, glycol ethers, chlorofluorocarbon polymers or silicones) and one or more thickening agents comprising inert organic or inorganic fillers (such as silicates, asbestos fibers, silica, cellulose derivatives or polyamides ) and, on the other hand, volatile agents that are intended to be accommodated in a reservoir mounted on the wheel for release 'in runflat for mixing with said non-volatile agents, which preferably comprise the water and a surfactant.
  • any known lubricating agent such as water, oils, esters, silanes, surfactants , polyoxyalkene glycols, glycol ethers, chlorofluorocarbon polymers or silicones
  • thickening agents comprising inert organic or inorganic fillers (such
  • support / casing lubricating compositions have been tested which are specifically intended to reduce the friction between said support and the internal face of the casing surrounding the support, under more severe conditions of run-flat and load and over durations significantly longer than those relating to previous tests without safety support. These compositions are usually applied to the internal face of the casing, prior to mounting it on the rim.
  • Patent document FR-A-2 480 201 presents a support / envelope lubricating composition
  • a support / envelope lubricating composition comprising, according to a mass fraction of approximately 70%, a lubricating agent consisting of a polyglycol and, according to a mass fraction of approximately 30%, a thickening agent comprising a multitude of solid particles including rubber powder and glass and plastic beads and, optionally, a silicon oxide.
  • the patent document FR-A-2 415 551 also presents a lubricating support / envelope composition, which comprises a lubricating agent consisting for example of a polypropylene glycol and a thickening agent comprising rubber and crushed tire cables, components. fibrous such as asbestos, and silica.
  • WO 02/04237 discloses a support / envelope lubricating composition
  • a support / envelope lubricating composition comprising, on the one hand, a lubricating agent and, on the other hand, a polysaccharide intended to thicken said agent.
  • lubricant this lubricating agent comprising glycerin for at least 60% by weight, and being present in the composition according to a mass fraction of between 95% and 99%.
  • the object of the present invention is to propose a new lubricating composition which can be used to lubricate the interface between a tire casing and a safety support mounted on a wheel rim inside the casing.
  • the invention also relates to the use of a lubricant composition according to the invention • for lubricating an interface between a tire casing for a motor vehicle, and a safety support mounted on a wheel rim inside said casing.
  • the invention also relates to a tire covering comprising a radially internal face intended to face a wheel rim on which it is intended to be mounted, and such that said radially internal face is provided with a lubricating composition according to the invention. .
  • the invention also relates to an assembly mounted according to the invention for a motor vehicle comprising a rim, a safety support which is mounted on said rim and of which at least the radially outer face consists of a rubber composition or of a material. plastic, and a tire cover mounted on said rim around said support, said rim having in each of its two peripheral edges a rim seat on which is mounted a bead of said cover, said rim comprising between its two seats a bearing receiving said support.
  • This mounted assembly has the characteristic of being provided with the lubricating composition according to the invention intended to lubricate the envelope / safety support interface.
  • the assembly mounted according to the invention is provided with the lubricating composition on the radially internal face of the casing which faces the rim.
  • FIG. 1 a side view of a support safety for inclusion in a mounted assembly according to the invention
  • Fig. 2 an axial section view of an assembly mounted according to the invention, in which the support of FIG. 1 is mounted on a wheel rim and is in the support position against a tire casing.
  • the level (or mass fraction) of silica must be greater than 4.0% and less than 7.5%, otherwise the endurance levels in run-flat required for the assembled assemblies of the invention is not achieved.
  • the silica content is preferably within a range of 5.3% to 6.7%, more preferably still in a range of 5.5% to 6.5%.
  • a mass fraction of silica equal to approximately 6.0% (or 6 ⁇ 0.3%) has been found to be optimal in a large number of cases.
  • the silica that can be used is any silica known to a person skilled in the art, for example a precipitated or preferably pyrogenic silica, having BET and CTAB specific surfaces preferably less than 450 m 2 / g.
  • the BET specific surface area (“mass area”) is determined by gas adsorption using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society” Nol. 60, page 309, February 1938), more precisely according to the French standard ⁇ F ISO 9277 of December 1996 [multi-point volumetric method (5 points) - gas: nitrogen - degassing: 1 hour at 160 ° C - relative pressure range p / in : 0.05 to 0.17].
  • the CTAB specific surface is the external surface determined according to French standard ⁇ F T 45-007 of November 1987 (method B).
  • a silica having a BET surface of between 50 and 350 m 2 / g is used. Above 350 m 2 / g, the endurance of the mounted assembly of the invention may deviate from the optimum, while the strengthening of the composition may be affected below 50 m 2 / g.
  • a silica having a BET surface area of between 100 and 250 m / g will be chosen more preferably, in particular when the safety support is a support made of diene elastomer such as natural rubber, or of polyurethane elastomer.
  • the polyoxyallene (or polyoxyalkene) used is preferably a polyalkylene glycol.
  • the alkylene (or alkene) is preferably chosen from ethylene, propylene and butylene.
  • a copolymer or a mixture of polymers of ethylene oxide and of propylene oxide is used.
  • the latter comprises units originating from ethylene oxide according to a preferred molar fraction of 40 to 80% (in particular from 50 to 70%), and units originating from the oxide of propylene according to a preferred molar fraction of 20 to 60% (in particular from 30 to 50%).
  • the polyoxyalkene has a number-average molecular mass (denoted Mn) of between 1000 and 1.0000 g / mol and, more preferably between 2,000 and 6,000 g / mol.
  • Mn number-average molecular mass
  • Ip polymolecularity index
  • a water-soluble grade polyoxyalkene is used, which makes it possible, if necessary, to extract the product, for example from the assembled assembly, by a simple washing with water.
  • This viscosity adjustment will of course be carried out while respecting the required range of silica concentration (between 4.0 and 7.5%) so as not to penalize the endurance of the assembly assembled in run-flat condition.
  • a polyoxyalkene of viscosity comprised in a range from 300 to 700 mPa.s, for example from 400 to 650 mPa.s, in particular in the case of a diene elastomer safety support. such as natural rubber.
  • lubricating composition does not require the presence of water, which promotes the interaction of the lubricating agent (polyoxyalkene) with the thickening agent (silica). This is why it can be described as “non-aqueous” or of the non-aqueous type, although it can withstand the presence of water in small quantity; by "nonaqueous" composition is meant in the present application a composition preferably comprising less than 2%, more preferably less than 1% by weight of water (% by weight of lubricating composition).
  • the composition according to the invention is also devoid of any other. volatile liquid vaporizable at a temperature less than or equal to 150 ° C., such as for example an alcohol or a salt (for example a salt of an alkali metal).
  • volatile liquid vaporizable at a temperature less than or equal to 150 ° C. such as for example an alcohol or a salt (for example a salt of an alkali metal).
  • the lubricant composition according to the invention may also comprise one or more various additives such as anti-oxidant, dye, bactericide, ionic or non-ionic surfactant, the level of each of these additives being preferably less than 2% (% by weight of composition).
  • various additives such as anti-oxidant, dye, bactericide, ionic or non-ionic surfactant, the level of each of these additives being preferably less than 2% (% by weight of composition).
  • the radially external face of said support comprises a rubber composition
  • the latter is based on a diene elastomer (or rubber) (natural or synthetic) such as for example natural rubber, or an elastomeric polyurethane; advantageously use a support whose elastomeric matrix comprises natural rubber or polyurethane, on a majority or exclusive basis.
  • At least the radially external face of said support comprises a plastic material
  • the latter is based on a thermosetting polyurethane (TPU) or a thermoplastic elastomer (TPE); advantageously use a support whose plastic matrix comprises such a polyurethane or such an elastomer, on a majority or exclusive basis.
  • each support 1 tested in the following examples essentially comprises, as taught in particular by documents FR-A-2 746 347 (US ' 5,891,279) or WO 00/76791 (US 6,564,842) mentioned above:
  • a base 2 of generally annular shape; an apex 3, substantially annular, with on its radially outer wall (optionally) longitudinal grooves 5, and an annular body 4 for connection between the base 2 and the apex 3.
  • Fig. 2 illustrates in particular the function of a support 1 which is to support the tread 7 of the tire 8 (mounted on its rim 9) in the event of a large loss of inflation pressure thereof.
  • FIG. 2 shows a particular example of such a support 1, with a first solid part 4a of the annular body 4 as well as a second, part 4b consisting of recesses (see also FIG. 1) extending axially over substantially more of the half of the annular body 4, opening on the outside in a substantially axial direction.
  • These recesses 4b are regularly distributed over the entire circumference of the annular body 4 and they define partitions 6, which provide a direct radial connection between the apex 3 and the base 2 of the support 1.
  • This geometry has the advantage of stressing in bending and not in compression these partitions 6 when they are crushed.
  • the recesses 4b and therefore the partitions 6 are numerous enough to provide regular support during rolling under pressure.
  • each support 1 is based on natural rubber and it comprises a highly dispersible silica as a reinforcing filler.
  • the viscosity of each lubricating agent was measured according to standard EN ISO 2555, as indicated previously.
  • the macrostructure (Mw and Mn) was determined by steric exclusion chromatography at a temperature of 35 ° C (tetrahydrofuran solvent at flow rate of 1 ml / min; concentration 1 g / 1; mass calibration of polystyrene; detector consisting of a differential refractometer).
  • the molar levels of ethylene oxide and propylene oxide units were determined by NMR.
  • no additive was added to the lubricating compositions C1 to C-5 which therefore consist simply of the combination of the plasticizing agent and the silica.
  • Identical tire casings were provided with compositions C1 to C-5, by applying each of these according to determined masses on a median zone of the internal face of the corresponding tire casing, zone admitting substantially for plane of symmetry the equatorial plane of the envelope. Then these envelopes were mounted on identical rims as illustrated in FIG. 2, on which identical safety supports as previously described in relation to FIGS. Were previously mounted. 1 and 2.
  • the lubricants in this test are the products "Emkarox VG 217W” and “Emkarox VG 379W” used in the previous test. In these examples, no additive was added to the lubricant compositions which therefore consist simply of the combination of the plasticizing agent and the silica.
  • compositions were tested on a flat run as indicated above for test No. 1 (only 60 g of lubricating composition per envelope). The results are reported in Table 2 below.
  • compositions according to the invention offer the mounted assemblies an endurance clearly greater than 200 km, while the compositions C-6 of on the one hand, C-9 and C-10 on the other hand, show comparatively degraded endurance, despite the use, which must be emphasized, of an identical lubricating agent and a very similar silica content.
  • the lubricant compositions according to the invention make it possible to give the mounted assemblies of the invention lubrication and therefore endurance in run-flat which are clearly improved, even for a substantially reduced amount of lubricant composition applied.
  • the mounted assemblies of the invention have the advantageous preferential characteristic of comprising less than 200 g, more preferably less than 150 g of lubricating composition.
  • the amount of lubricating composition even remains less than 100 g.

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  • Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Engineering & Computer Science (AREA)
  • Emergency Medicine (AREA)
  • Health & Medical Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Lubricants (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Tires In General (AREA)

Abstract

The invention relates to a lubricating composition which can be used to lubricate an interface between a tyre casing and a safety support which is mounted to the wheel rim inside said casing. The invention further relates to one such casing and a mounted assembly for a motor vehicle which are provided with the aforementioned lubricating composition. The inventive lubricating composition is characterised in that it comprises an alkene oxide polymer (polyoxyalkene) as a lubricating agent and between 4 % and 7.5 % silica (weight percent of the lubricating composition) as a thickening agent.

Description

COMPOSITION LUBRIFIANTE POUR UN APPUI DE SECURITE D' UN PNEUMATIQUE LUBRICATING COMPOSITION FOR A TIRE SAFETY SUPPORT
La présente invention concerne une composition lubrifiante utilisable pour lubrifier une interface entre une enveloppe de pneumatique et un appui de sécurité monté sur une jante de roue à l'intérieur de ladite enveloppe, une telle enveloppe et un ensemble monté pour véhicule automobile pourvus de ladite composition lubrifiante. L'invention concerne également la lubrification entre l'appui et l'enveloppe en roulage à plat, suite à une chute de pression de gonflage à l'intérieur de ladite enveloppe.The present invention relates to a lubricating composition which can be used to lubricate an interface between a tire casing and a safety support mounted on a wheel rim inside said casing, such casing and a mounted assembly for a motor vehicle provided with said composition lubricating. The invention also relates to lubrication between the support and the casing when running flat, following a drop in inflation pressure inside said casing.
Pour retarder, lors du roulage à pression réduite ou nulle (dit roulage « à plat ») d'une, enveloppe de pneumatique, la détérioration par échauffement des zones de frottement entre diverses parties de la face interne de l'enveloppe ou bien entre celle-ci et la jante métallique de roue, on a cherché par le passé à pourvoir la face interne de l'enveloppe d'une composition lubrifiante destinée à réduire la friction entre ces zones de frottement.To delay, during rolling at reduced or zero pressure (called "flat" rolling) of a tire, the deterioration by heating of the friction zones between various parts of the internal face of the tire or between that -ci and the metal wheel rim, attempts have been made in the past to provide the internal face of the casing with a lubricating composition intended to reduce the friction between these friction zones.
Ces compositions lubrifiantes enveloppe/enveloppe ou jante/enveloppe comprennent de manière connue :These envelope / envelope or rim / envelope lubricant compositions comprise, in a known manner:
un agent lubrifiant, tel que par exemple un polymère d'oxyde d'alcène (ou polyoxyalcène) ou de la glycérine ; un agent épaississant, tel qu'une silice, destiné à élever la viscosité de l'agent lubrifiant de sorte à minimiser le coulage dudit agent lubrifiant en raison de la pesanteur lorsque le véhicule est au repos ou roule avec ses enveloppes de pneumatique à l'état gonflé ; un ou plusieurs liquides volatiles qui sont vaporisables lors d'un roulage à plat, tel que de l'eau, un alcool ou un sel en solution aqueuse ; et un agent de renforcement tensioactif également en solution aqueuse.a lubricating agent, such as for example a polymer of alkene oxide (or polyoxyalkene) or glycerin; a thickening agent, such as silica, intended to increase the viscosity of the lubricating agent so as to minimize the flow of said lubricating agent due to gravity when the vehicle is at rest or is rolling with its tire casings swollen state; one or more volatile liquids which are vaporizable during a run-flat, such as water, an alcohol or a salt in aqueous solution; and a surfactant reinforcing agent also in aqueous solution.
On peut citer à titre d'exemple le document brevet FR-A-2 293 486 (ou US 4,051,884) qui présente une composition lubrifiante destinée à lubrifier l'interface enveloppe/ enveloppe ou enveloppe/ roue, qui comprend un agent lubrifiant, un agent épaississant, un liquide volatile et un agent de renforcement tensioactif. L'agent lubrifiant de cette composition est constitué d'un polyoxyalcène, de préférence un copolymère d'oxyde d'éthylène et d'oxyde de propylène. L'agent épaississant utilisé est une silice finement divisée dont la fraction massique dans la composition lubrifiante doit être impérativement d'au moins 7,5%, cette fraction massique variant de 8,4% à. 9,0% dans les exemples de réalisation. Cet agent lubrifiant comprend également de l'eau à titre de liquide volatile destiné à abaisser la viscosité relativement élevée de ce copolymère. Enfin, l'agent de renforcement tensioactif consiste en un sel ionique d'un métal alcalin de pH compris entre 5,5 et 8,5 en solution aqueuse. On peut également citer le brevet US-A-3 946 783 qui présente une composition lubrifiante destinée à lubrifier l'interface enveloppe/ roue. Cette composition comprend, d'une part, des agents non volatiles qui sont destinés à être logés à l'intérieur de l'enveloppe et qui comprennent tout agent lubrifiant connu (tel que de l'eau, des huiles, esters, silanes, tensioactifs, polyoxyalcène glycols, éthers de glycol, polymères de chlorofluorocarbone ou silicones) et un ou des agents épaississants comprenant des charges inertes organiques ou inorganiques (telles que des silicates, des fibres d'amiante, de la silice, des dérivés de cellulose ou des polyamides) et, d'autre part, des agents volatiles qui sont destinés à être logés dans un réservoir monté sur la roue en vue de leur libération' en roulage à plat pour leur mélange avec lesdits agents non volatiles et qui comprennent de préférence de l'eau et un tensioactif.By way of example, mention may be made of patent document FR-A-2 293 486 (or US 4,051,884) which has a lubricating composition intended to lubricate the envelope / envelope or envelope / wheel interface, which comprises a lubricating agent, an agent thickener, a volatile liquid and a surfactant reinforcing agent. The lubricant of this composition consists of a polyoxyalkene, preferably a copolymer of ethylene oxide and propylene oxide. The thickening agent used is a finely divided silica whose mass fraction in the lubricating composition must imperatively be at least 7.5%, this mass fraction varying from 8.4% to . 9.0% in the example embodiments. This lubricating agent also comprises water as a volatile liquid intended to lower the relatively high viscosity of this copolymer. Finally, the surfactant reinforcing agent consists of an ionic salt of an alkali metal of pH between 5.5 and 8.5 in aqueous solution. Mention may also be made of US-A-3,946,783 which has a lubricating composition intended to lubricate the casing / wheel interface. This composition comprises, on the one hand, non-volatile agents which are intended to be housed inside the envelope and which comprise any known lubricating agent (such as water, oils, esters, silanes, surfactants , polyoxyalkene glycols, glycol ethers, chlorofluorocarbon polymers or silicones) and one or more thickening agents comprising inert organic or inorganic fillers (such as silicates, asbestos fibers, silica, cellulose derivatives or polyamides ) and, on the other hand, volatile agents that are intended to be accommodated in a reservoir mounted on the wheel for release 'in runflat for mixing with said non-volatile agents, which preferably comprise the water and a surfactant.
Plus récemment, on a cherché à améliorer l'endurance des ensembles montés, dans des conditions de roulage à pression de gonflage réduite ou nulle, en prévoyant un appui de sécurité spécifique à l'intérieur du pneumatique, monté sur la jante de roue de manière à pouvoir soutenir la bande de roulement de l'enveloppe en cas de chute de la pression de gonflage. Pour la description de tels appuis, on peut citer par exemple les documents dé brevet FR-A-2 746 347 (ou US 5,891,279) ou WO 00/76791 (ou US 6,564,842).More recently, attempts have been made to improve the endurance of mounted assemblies, under running conditions with reduced or zero inflation pressure, by providing a specific safety support inside the tire, mounted on the wheel rim so to be able to support the tread of the tire in the event of a drop in inflation pressure. For the description of such supports, mention may be made, for example, of the patent documents FR-A-2 746 347 (or US 5,891,279) or WO 00/76791 (or US 6,564,842).
Dans ce contexte, on a testé des compositions lubrifiantes appui/ enveloppe qui sont spécifiquement destinées à réduire la friction entre ledit appui et la face interne de l'enveloppe entourant l'appui, dans des conditions de roulage à plat et de charge plus sévères et sur des durées nettement supérieures à celles se rapportant aux tests antérieurs sans appui de sécurité. Ces compositions sont usuellement appliquées sur la face interne de l'enveloppe, préalablement au montage de celle-ci sur la jante.In this context, support / casing lubricating compositions have been tested which are specifically intended to reduce the friction between said support and the internal face of the casing surrounding the support, under more severe conditions of run-flat and load and over durations significantly longer than those relating to previous tests without safety support. These compositions are usually applied to the internal face of the casing, prior to mounting it on the rim.
Le document de brevet FR-A-2 480 201 (ou GB-A-2 074 955) présente une composition lubrifiante appui/ enveloppe comprenant, selon une fraction massique d'environ 70%, un agent lubrifiant constitué d'un polyglycol et, selon une fraction massique d'environ 30%, un agent épaississant comprenant une multitude de particules solides incluant de la poudre de caoutchouc et des billes de verre et de plastique et, optionnellement, un oxyde de silicium.Patent document FR-A-2 480 201 (or GB-A-2 074 955) presents a support / envelope lubricating composition comprising, according to a mass fraction of approximately 70%, a lubricating agent consisting of a polyglycol and, according to a mass fraction of approximately 30%, a thickening agent comprising a multitude of solid particles including rubber powder and glass and plastic beads and, optionally, a silicon oxide.
Le document de brevet FR-A-2 415 551 (ou GB-A-2 013 143) présente également une composition lubrifiante appui/ enveloppe, qui comprend un agent lubrifiant constitué par exemple d'un polypropylène glycol et un agent épaississant comprenant du caoutchouc et des câbles de pneumatique broyés, des éléments . fibreux tels que de l'amiante, et de la silice.The patent document FR-A-2 415 551 (or GB-A-2 013 143) also presents a lubricating support / envelope composition, which comprises a lubricating agent consisting for example of a polypropylene glycol and a thickening agent comprising rubber and crushed tire cables, components. fibrous such as asbestos, and silica.
Plus récemment, la demande de brevet internationale WO 02/04237 (ou US 2003/087766) divulgue une composition lubrifiante appui/ enveloppe comprenant, d'une part, un agent lubrifiant et, d'autre part, un polysaccharide destiné à épaissir ledit agent lubrifiant, cet agent lubrifiant comprenant de la glycérine pour au moins 60% en poids, et étant présent dans la composition selon une fraction massique comprise entre 95% et 99%. Le but de la présente invention est de proposer une nouvelle composition lubrifiante utilisable pour lubrifier l'interface entre une enveloppe de pneumatique et un appui de sécurité monté sur une jante de roue à l'intérieur de l'enveloppe.More recently, international patent application WO 02/04237 (or US 2003/087766) discloses a support / envelope lubricating composition comprising, on the one hand, a lubricating agent and, on the other hand, a polysaccharide intended to thicken said agent. lubricant, this lubricating agent comprising glycerin for at least 60% by weight, and being present in the composition according to a mass fraction of between 95% and 99%. The object of the present invention is to propose a new lubricating composition which can be used to lubricate the interface between a tire casing and a safety support mounted on a wheel rim inside the casing.
Les Demanderesses ont découvert, de manière inattendue, que l'association dans ladite composition lubrifiante d'un agent lubrifiant comportant un polymère d'oxyde d'alcène avec un faible taux de silice à titre d'agent épaississant, dans un domaine étroit compris entre 4,0% et 7,5% (% en poids de composition lubrifiante), permet d'empêcher le coulage de ladite composition avant le roulage à plat et d'assurer en roulage à plat une lubrification et donc une endurance toutes deux améliorées par rapport à celles procurées par les compositions lubrifiantes connues. Ces résultats peuvent en outre être obtenus en utilisant des quantités réduites de composition lubrifiante.The Applicants have discovered, unexpectedly, that the combination in said lubricating composition of a lubricating agent comprising an alkene oxide polymer with a low level of silica as thickening agent, in a narrow range between 4.0% and 7.5% (% by weight of lubricating composition), makes it possible to prevent the flow of said composition before running flat and to provide lubrication and therefore endurance both while running flat, improved by compared to those provided by known lubricant compositions. These results can furthermore be obtained by using reduced amounts of lubricating composition.
L'invention concerne également l'utilisation d'une composition lubrifiante selon l'invention • pour lubrifier une interface entre une enveloppe de pneumatique pour véhicule automobile, et un appui de sécurité monté sur une jante de roue à l'intérieur de ladite enveloppe.The invention also relates to the use of a lubricant composition according to the invention • for lubricating an interface between a tire casing for a motor vehicle, and a safety support mounted on a wheel rim inside said casing.
L'mvention concerne également une enveloppe de pneumatique comportant une face radial ement interne destinée à faire face à une jante de roue sur laquelle elle est destinée à être montée, et telle que ladite face radialement interne est pourvue d'une composition lubrifiante selon l'invention. .The invention also relates to a tire covering comprising a radially internal face intended to face a wheel rim on which it is intended to be mounted, and such that said radially internal face is provided with a lubricating composition according to the invention. .
L'invention concerne également un ensemble monté selon l'invention pour véhicule automobile comportant une jante, un appui de sécurité qui est monté sur ladite jante et dont au moins la face radialement externe est constituée d'une composition de caoutchouc ou d'une matière plastique, et une enveloppe de pneumatique montée sur ladite jante autour dύdit appui, ladite jante présentant en chacun de ses deux bords périphériques un siège de jante sur lequel est monté un bourrelet de ladite enveloppe, ladite jante comportant entre ses deux sièges une portée recevant ledit appui. Cet ensemble monté a pour caractéristique d'être pourvu de la composition lubrifiante selon l'invention destinée à lubrifier l'interface enveloppe/ appui de sécurité.The invention also relates to an assembly mounted according to the invention for a motor vehicle comprising a rim, a safety support which is mounted on said rim and of which at least the radially outer face consists of a rubber composition or of a material. plastic, and a tire cover mounted on said rim around said support, said rim having in each of its two peripheral edges a rim seat on which is mounted a bead of said cover, said rim comprising between its two seats a bearing receiving said support. This mounted assembly has the characteristic of being provided with the lubricating composition according to the invention intended to lubricate the envelope / safety support interface.
De préférence, l'ensemble monté selon l'invention est pourvu de la composition lubrifiante sur la face radialement interne de l'enveloppe qui fait face à la jante.Preferably, the assembly mounted according to the invention is provided with the lubricating composition on the radially internal face of the casing which faces the rim.
L'invention sera aisément comprise à la lumière de la description détaillée qui suit ainsi que des figures annexées représentant :The invention will be easily understood in the light of the detailed description which follows as well as of the appended figures representing:
à la Fig. 1 , une vue de côté d'un appui' de sécurité destiné à être inclus dans un ensemble monté selon l'invention ; à la Fig. 2, une vue en coupe axiale d'un ensemble monté selon l'invention, dans lequel l'appui de la Fig. 1 est monté sur une jante de roue et se trouve en position d'appui contre une enveloppe de pneumatique.in Fig. 1, a side view of a support safety for inclusion in a mounted assembly according to the invention; in Fig. 2, an axial section view of an assembly mounted according to the invention, in which the support of FIG. 1 is mounted on a wheel rim and is in the support position against a tire casing.
Dans la composition lubrifiante selon l'invention, le taux (ou fraction massique) de silice doit être supérieur à 4,0% et inférieur à 7,5%, sinon les niveaux d'endurance en roulage à plat requis pour les ensembles montés de l'invention ne sont pas atteints. Pour cette raison, le taux de silice est de préférence compris dans un domaine de 5,3% à 6,7%, plus préferentiellement encore dans un domaine de 5,5% à 6,5%. Une fraction massique de silice égale à environ 6,0% (soit 6 ± 0,3%) s'est révélée optimale dans un grand nombre de cas.In the lubricating composition according to the invention, the level (or mass fraction) of silica must be greater than 4.0% and less than 7.5%, otherwise the endurance levels in run-flat required for the assembled assemblies of the invention is not achieved. For this reason, the silica content is preferably within a range of 5.3% to 6.7%, more preferably still in a range of 5.5% to 6.5%. A mass fraction of silica equal to approximately 6.0% (or 6 ± 0.3%) has been found to be optimal in a large number of cases.
La silice utilisable est toute silice connue de l'homme du métier, par exemple une silice précipitée ou de préférence pyrogénée, présentant des surfaces spécifiques BET et CTAB préferentiellement inférieures à 450 m2/g.The silica that can be used is any silica known to a person skilled in the art, for example a precipitated or preferably pyrogenic silica, having BET and CTAB specific surfaces preferably less than 450 m 2 / g.
Dans le présent exposé, la surface spécifique ("aire massique") BET est déterminée par adsorption de gaz à l'aide, de la méthode de Brunauer-Emmett-Teller décrite dans "The Journal of the American Chemical Society" Nol. 60, page 309, février 1938), plus précisément selon la norme française ΝF ISO 9277 de décembre 1996 [méthode volumétrique multipoints (5 points) - gaz: azote - dégazage: 1 heure à 160°C - domaine de pression relative p/po : 0,05 à 0,17]. La surface spécifique CTAB est la surface externe déterminée selon la norme française ΝF T 45-007 de novembre 1987 (méthode B).In the present account, the BET specific surface area ("mass area") is determined by gas adsorption using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society" Nol. 60, page 309, February 1938), more precisely according to the French standard ΝF ISO 9277 of December 1996 [multi-point volumetric method (5 points) - gas: nitrogen - degassing: 1 hour at 160 ° C - relative pressure range p / in : 0.05 to 0.17]. The CTAB specific surface is the external surface determined according to French standard ΝF T 45-007 of November 1987 (method B).
Plus préferentiellement,. on utilise une silice ayant une surface BET comprise entre 50 et 350 m2/g. Au-delà de 350 m2/g, l'endurance de l'ensemble monté de l'invention peut s'écarter de l'optimum, alors que le renforcement de la composition risque d'être affecté en dessous de 50 m2/g. Pour ces raisons, on choisira plus préferentiellement une silice ayant une surface BET comprise entre 100 et 250 m /g, en particulier lorsque l'appui de sécurité est un appui en élastomère diénique tel que du caoutchouc naturel, ou en élastomère polyuréthanne.More preferably ,. using a silica having a BET surface of between 50 and 350 m 2 / g. Above 350 m 2 / g, the endurance of the mounted assembly of the invention may deviate from the optimum, while the strengthening of the composition may be affected below 50 m 2 / g. For these reasons, a silica having a BET surface area of between 100 and 250 m / g will be chosen more preferably, in particular when the safety support is a support made of diene elastomer such as natural rubber, or of polyurethane elastomer.
Le polyoxyal ylène (ou polyoxyalcène) utilisé est de préférence un polyalkylène glycol. D'autre part, l'alkylène (ou alcène) est de préférence choisi parmi éthylène, propylene et butylène.The polyoxyallene (or polyoxyalkene) used is preferably a polyalkylene glycol. On the other hand, the alkylene (or alkene) is preferably chosen from ethylene, propylene and butylene.
On utilise avantageusement un copolymère ou un mélange de polymères d'oxyde d'éthylène et d'oxyde de propylene. Dans le cas d'un tel copolymère, ce dernier comporte des unités issues de l'oxyde d'éthylène selon une fraction molaire préférentielle de 40 à 80% (en particulier de 50 à 70%), et des unités issues de l'oxyde de propylene selon une fraction molaire préférentielle de 20 à 60% (en particulier de 30 à 50%).Advantageously, a copolymer or a mixture of polymers of ethylene oxide and of propylene oxide is used. In the case of such a copolymer, the latter comprises units originating from ethylene oxide according to a preferred molar fraction of 40 to 80% (in particular from 50 to 70%), and units originating from the oxide of propylene according to a preferred molar fraction of 20 to 60% (in particular from 30 to 50%).
Selon une autre caractéristique préférentielle de l'invention, le polyoxyalcène présente une masse moléculaire moyenne en nombre (notée Mn) comprise entre 1 000 et 1.0 000 g/mol et, plus préferentiellement entre 2 000 et 6 000 g/mol. D'autre part, son indice de polymolécularité (noté Ip) est de préférence inférieur à 1,5, plus préferentiellement inférieur à 1,3 (rappel : Ip = Mw/Mn avec Mw masse moléculaire moyenne en poids).According to another preferred characteristic of the invention, the polyoxyalkene has a number-average molecular mass (denoted Mn) of between 1000 and 1.0000 g / mol and, more preferably between 2,000 and 6,000 g / mol. On the other hand, its polymolecularity index (noted Ip) is preferably less than 1.5, more preferably less than 1.3 (reminder: Ip = Mw / Mn with Mw average molecular weight by weight).
Selon une autre caractéristique préférentielle de l'invention, le polyoxyalcène utilisé présente une viscosité apparente comprise entre 100 et 1500 mPa.s (1 mPa.s = 1 cP), plus préferentiellement comprise entre 200 et 1000 mPa.s, ladite viscosité étant mesurée à 23 °C selon la norme européenne et internationale EN ISO 2555 (juin 1999) (viscosité selon le procédé de Brookfield ; viscosimètre rotatif du type A ; rotation de 20 tours/min ; mobile N°2 ; modèle RVT).According to another preferred characteristic of the invention, the polyoxyalkene used has an apparent viscosity of between 100 and 1500 mPa.s (1 mPa.s = 1 cP), more preferably between 200 and 1000 mPa.s, said viscosity being measured at 23 ° C according to European and international standard EN ISO 2555 (June 1999) (viscosity according to the Brookfield process; rotary viscometer of type A; rotation of 20 revolutions / min; mobile N ° 2; RVT model).
On utilise avantageusement un polyoxyalcène de grade soluble dans l'eau, ce qui permet le cas échéant d'extraire le produit, par exemple de l'ensemble monté, par un simple lavage à l'eau.Advantageously, a water-soluble grade polyoxyalkene is used, which makes it possible, if necessary, to extract the product, for example from the assembled assembly, by a simple washing with water.
A la lumière de la description et des exemples de réalisation qui suivent, l'homme du métier saura aisément, en ajustant la viscosité de l'agent lubrifiant, contrôler celle de la composition lubrifiante en fonction des conditions particulières de réalisation de l'invention, notamment de la nature et géométrie de l'appui de sécurité, ceci afin d'éviter :In the light of the description and of the exemplary embodiments which follow, the person skilled in the art will easily know, by adjusting the viscosity of the lubricating agent, to control that of the lubricating composition as a function of the particular conditions for carrying out the invention, in particular the nature and geometry of the safety support, this in order to avoid:
en raison d'une fluidité trop élevée, le risque d'un écoulement parasite de la composition au repos, écoulement pouvant générer un problème de balourd en roulage ultérieur en conditions normales (sous pression de gonflage nominale) ; en raison d'une fluidité trop faible, le risque d'une distribution non uniforme de la composition autour de l'appui de sécurité, en conditions de roulage à plat, nuisible à l'endurance globale de l'ensemble monté.due to excessively high fluidity, the risk of a parasitic flow of the composition at rest, flow which may generate an imbalance problem during subsequent driving under normal conditions (under nominal inflation pressure); due to too low fluidity, the risk of a non-uniform distribution of the composition around the safety support, in run-flat conditions, detrimental to the overall endurance of the assembled assembly.
Cet ajustement de viscosité sera bien entendu réalisé tout en respectant la fourchette requise de concentration en silice (entre 4,0 et 7,5%) afin de ne pas pénaliser l'endurance de l'ensemble monté en condition de roulage à plat.This viscosity adjustment will of course be carried out while respecting the required range of silica concentration (between 4.0 and 7.5%) so as not to penalize the endurance of the assembly assembled in run-flat condition.
C'est ainsi que l'on pourra utiliser avantageusement un polyoxyalcène de viscosité comprise dans un domaine de 300 à 700 mPa.s, par exemple de 400 à 650 mPa.s, notamment dans le cas d'un appui de sécurité en élastomère diénique tel que du caoutchouc naturel.This is why it is advantageous to use a polyoxyalkene of viscosity comprised in a range from 300 to 700 mPa.s, for example from 400 to 650 mPa.s, in particular in the case of a diene elastomer safety support. such as natural rubber.
Des domaines de viscosité plus élevés, par exemple compris dans un domaine de 450 à 850 mPa.s, conviennent également à l'invention, par exemple dans le cas d'appuis de sécurité en élastomère polyuréthanne.Higher viscosity ranges, for example within a range of 450 to 850 mPa.s, are also suitable for the invention, for example in the case of safety bearings made of polyurethane elastomer.
Une autre caractéristique avantageuse de la composition lubrifiante selon l'invention est qu'elle ne nécessite pas la présence d'eau, ce qui favorise l'interaction de l'agent lubrifiant (polyoxyalcène) avec l'agent épaississant (silice). C'est en cela qu'elle peut être qualifiée de "non-aqueuse" ou du type non-aqueuse, bien qu'elle puisse supporter sans dommage la présence d'eau en faible quantité ; par composition "non aqueuse", on entend dans la présente demande une composition comportant de préférence moins de 2%, plus préferentiellement moins de 1% en poids d'eau (% en poids de composition lubrifiante).Another advantageous characteristic of the lubricating composition according to the invention is that it does not require the presence of water, which promotes the interaction of the lubricating agent (polyoxyalkene) with the thickening agent (silica). This is why it can be described as "non-aqueous" or of the non-aqueous type, although it can withstand the presence of water in small quantity; by "nonaqueous" composition is meant in the present application a composition preferably comprising less than 2%, more preferably less than 1% by weight of water (% by weight of lubricating composition).
A titre préférentiel, la composition selon l'invention est en outre dépourvue de tout autre . liquide volatile vaporisable à une température inférieure ou égale à 150°C, tel que par exemple un alcool ou un sel (par exemple un sel d'une métal alcalin).Preferably, the composition according to the invention is also devoid of any other. volatile liquid vaporizable at a temperature less than or equal to 150 ° C., such as for example an alcohol or a salt (for example a salt of an alkali metal).
On notera que la composition lubrifiante selon l'invention peut comprendre en outre un ou des' additifs divers tels qu'anti oxydant, colorant, bactéricide, tensioactif ionique ou non ionique, le taux de chacun de ces additifs étant de préférence inférieur à 2% (% en poids de composition).It will be noted that the lubricant composition according to the invention may also comprise one or more various additives such as anti-oxidant, dye, bactericide, ionic or non-ionic surfactant, the level of each of these additives being preferably less than 2% (% by weight of composition).
Selon un mode avantageux de réalisation de l'invention dans lequel au moins la face radialement externe dudit appui comporte une composition de caoutchouc, cette dernière est à base d'un élastomère (ou caoutchouc) diénique (naturel ou synthétique) tel que par exemple du caoutchouc naturel, ou encore un polyuréthanne élastomérique ; on utilisera avantageusement un appui dont la matrice élastomère comprend du caoutchouc naturel ou du polyuréthanne, à titre majoritaire ou exclusif. • According to an advantageous embodiment of the invention in which at least the radially external face of said support comprises a rubber composition, the latter is based on a diene elastomer (or rubber) (natural or synthetic) such as for example natural rubber, or an elastomeric polyurethane; advantageously use a support whose elastomeric matrix comprises natural rubber or polyurethane, on a majority or exclusive basis. •
Selon un autre mode avantageux de réalisation de l'invention dans lequel au moins la face radialement externe dudit appui comporte une matière plastique, cette dernière est à base d'un polyuréthanne thermodurcissable (TPU) ou d'un élastomère thermoplastique (TPE) ; on utilisera avantageusement un appui dont la matrice plastique comprend un tel polyuréthanne ou un tel élastomère, à titre majoritaire ou exclusif.According to another advantageous embodiment of the invention in which at least the radially external face of said support comprises a plastic material, the latter is based on a thermosetting polyurethane (TPU) or a thermoplastic elastomer (TPE); advantageously use a support whose plastic matrix comprises such a polyurethane or such an elastomer, on a majority or exclusive basis.
En référence aux Fig. 1 et 2, chaque appui 1 testé dans les exemples qui suivent comprend essentiellement, comme enseigné notamment par les documents FR-A-2 746 347 (US ' 5,891,279) ou WO 00/76791 (US 6,564,842) précités :With reference to Figs. 1 and 2, each support 1 tested in the following examples essentially comprises, as taught in particular by documents FR-A-2 746 347 (US ' 5,891,279) or WO 00/76791 (US 6,564,842) mentioned above:
une base 2, de forme généralement annulaire ; un sommet 3, sensiblement annulaire, avec sur sa paroi radialement extérieure (de façon optionnelle) des rainures longitudinales 5, et un corps annulaire 4 de liaison entre la base 2 et le sommet 3.a base 2, of generally annular shape; an apex 3, substantially annular, with on its radially outer wall (optionally) longitudinal grooves 5, and an annular body 4 for connection between the base 2 and the apex 3.
La Fig. 2 illustre notamment la fonction d'un appui 1 qui est de supporter la bande de roulement 7 du pneumatique 8 (monté sur sa jante 9) en cas de forte perte de pression de gonflage de celui-ci.Fig. 2 illustrates in particular the function of a support 1 which is to support the tread 7 of the tire 8 (mounted on its rim 9) in the event of a large loss of inflation pressure thereof.
La coupe de la Fig. 2 montre un exemple particulier d'un tel appui 1, avec une première partie massive 4a du corps annulaire 4 ainsi qu'une seconde, partie 4b constituée d'évidements (voir également Fig. 1) s'étendant axialement sur sensiblement plus de la moitié du corps annulaire 4, en débouchant du côté extérieur dans une direction sensiblement axiale. Ces évidements 4b sont régulièrement répartis sur toute la circonférence du corps annulaire 4 et ils définissent des cloisons 6, lesquelles assurent une liaison radiale directe entre le sommet 3 et la base 2 de l'appui 1.The section of FIG. 2 shows a particular example of such a support 1, with a first solid part 4a of the annular body 4 as well as a second, part 4b consisting of recesses (see also FIG. 1) extending axially over substantially more of the half of the annular body 4, opening on the outside in a substantially axial direction. These recesses 4b are regularly distributed over the entire circumference of the annular body 4 and they define partitions 6, which provide a direct radial connection between the apex 3 and the base 2 of the support 1.
Cette géométrie a l'avantage de solliciter en flexion et non en compression ces cloisons 6 lorsqu'elles sont écrasées. Les évidements 4b et donc les cloisons 6 sont suffisamment nombreux pour procurer un support régulier lors du roulage sous appui.This geometry has the advantage of stressing in bending and not in compression these partitions 6 when they are crushed. The recesses 4b and therefore the partitions 6 are numerous enough to provide regular support during rolling under pressure.
Dans les exemples de réalisation qui suivent, les dimensions caractéristiques en mm de chaque appui 1 (respectivement largeur - diamètre intérieur - hauteur) sont de 115 - 420 - 45. Chaque appui 1 est à base de caoutchouc naturel et il comprend une silice hautement dispersible à titre de charge renforçante.In the following exemplary embodiments, the characteristic dimensions in mm of each support 1 (respectively width - internal diameter - height) are 115 - 420 - 45. Each support 1 is based on natural rubber and it comprises a highly dispersible silica as a reinforcing filler.
Essai 1Trial 1
Dans ce premier essai, 5 compositions lubrifiantes conformes ou non à l'invention, notées C-l à C-5, sont préparées avec les agents lubrifiants suivants :In this first test, 5 lubricating compositions conforming or not to the invention, denoted C-1 to C-5, are prepared with the following lubricating agents:
C-l (témoin) : glycérine technique (à 90% de pureté) ;C-1 (control): technical glycerin (90% purity);
C-2 (invention) : copolymère d'oxyde d'éthylène et d'oxyde de propylene, commercialisé par la société Uniquema sous la dénomination "Emkarox NG 217W"C-2 (invention): copolymer of ethylene oxide and propylene oxide, sold by the company Uniquema under the name "Emkarox NG 217W"
(viscosité = 440 mPa.s - Mn = 4400 g/mol - Mw = 4900 g/mol, Ip = 1,11 - taux molaires d'unités oxyde d'éthylène et oxyde de propylene respectivement de 58 % et 42 %) ; ' C-3 (invention) : copolymère d'oxyde d'éthylène et d'oxyde de propylene, commercialisé par Uniquema sous la dénomination "Emkarox VG 379W" (viscosité(viscosity = 440 mPa.s - Mn = 4400 g / mol - Mw = 4900 g / mol, Ip = 1.11 - molar levels of ethylene oxide and propylene oxide units of 58% and 42% respectively); ' C-3 (invention): copolymer of ethylene oxide and propylene oxide, sold by Uniquema under the name "Emkarox VG 379W" (viscosity
= 650 mPa.s - Mn = 5500 g/mol - Mw = 6800 g/mol, Ip = 1,25 - taux molaires d'unités oxyde d'éthylène et oxyde de propylene respectivement de 59 % et 41 %) ; Ç-4 (invention) : copolymère d'oxyde d'éthylène et d'oxyde de propylene, commercialisé par Uniquema sous la dénomination "Emkarox NG 650W" (viscosité = 850 mPa.s) ;= 650 mPa.s - Mn = 5500 g / mol - Mw = 6800 g / mol, Ip = 1.25 - molar levels of ethylene oxide and propylene oxide units respectively 59% and 41%); Ç-4 (invention): copolymer of ethylene oxide and propylene oxide, sold by Uniquema under the name "Emkarox NG 650W" (viscosity = 850 mPa.s);
C-5 (invention) : copolymère d'oxyde d'éthylène et d'oxyde de propylene, commercialisé par Uniquema sous la dénomination "Emkarox VG 1051W" (viscosité = 1400 mPa.s - Mn = 8400 g/mol - Mw = 10900 g/mol, Ip = 1 ,30 - taux molaires d'unités oxyde d'éthylène et oxyde de propylene respectivement de 62% et 38%).C-5 (invention): copolymer of ethylene oxide and propylene oxide, sold by Uniquema under the name "Emkarox VG 1051W" (viscosity = 1400 mPa.s - Mn = 8400 g / mol - Mw = 10900 g / mol, Ip = 1.30 - molar levels of ethylene oxide and propylene oxide units of 62% and 38% respectively).
La viscosité de chaque agent lubrifiant a été mesurée selon la norme EN ISO 2555, comme indiqué précédemment. La macrostructure (Mw et Mn) a été déterminée par chromatographie d'exclusion stérique à la température de 35°C (solvant tétrahydrofurane selon débit de 1 ml/min ; concentration 1 g/1 ; étalonnage en masse de polystyrène ; détecteur constitué d'un réfractomètre différentiel). Les taux molaires d'unités oxyde d'éthylène et oxyde de propylene ont été déterminés par RMN. Chacune de ces compositions comporte en outre, à titre d'agent épaississant, 5,4% de silice pyrogénée présentant une surface BET comprise entre 100 et 250 m2/g (dénomination "Cabosil M5" de la société Cabot - BET = 200 m2/g). Dans ces exemples, aucun additif n'a été ajouté aux compositions lubrifiantes C-l à C-5 qui consistent donc simplement en la combinaison de l'agent plastifiant et de la silice.The viscosity of each lubricating agent was measured according to standard EN ISO 2555, as indicated previously. The macrostructure (Mw and Mn) was determined by steric exclusion chromatography at a temperature of 35 ° C (tetrahydrofuran solvent at flow rate of 1 ml / min; concentration 1 g / 1; mass calibration of polystyrene; detector consisting of a differential refractometer). The molar levels of ethylene oxide and propylene oxide units were determined by NMR. Each of these compositions also comprises, as thickening agent, 5.4% of fumed silica having a BET surface area between 100 and 250 m 2 / g (name "Cabosil M5" from the company Cabot - BET = 200 m 2 / g). In these examples, no additive was added to the lubricating compositions C1 to C-5 which therefore consist simply of the combination of the plasticizing agent and the silica.
Des enveloppes de pneumatique identiques ont été pourvues des compositions C-l à C-5, en appliquant chacune de ces dernières selon des masses déterminées sur une zone médiane de la face interne de l'enveloppe de pneumatique correspondante, zone admettant sensiblement pour plan de symétrie le plan équatorial de l'enveloppe. Puis on a monté ces enveloppes sur des jantes identiques telles qu'illustrées à la Fig. 2, sur lesquelles avaient été préalablement montés des appuis de sécurité identiques tels que décrits précédemment en relation avec les Fig. 1 et 2.Identical tire casings were provided with compositions C1 to C-5, by applying each of these according to determined masses on a median zone of the internal face of the corresponding tire casing, zone admitting substantially for plane of symmetry the equatorial plane of the envelope. Then these envelopes were mounted on identical rims as illustrated in FIG. 2, on which identical safety supports as previously described in relation to FIGS. Were previously mounted. 1 and 2.
Les dimensions caractéristiques de chaque ensemble monté ainsi obtenu, destiné à équiper ' un véhicule automobile de marque "RENAULT" (modèle "SCENIC") sont en mm : 185 - 620 - 420 (respectivement, largeur d'enveloppe - diamètre d'enveloppe - diamètre de jante).The characteristic dimensions of each assembled assembly thus obtained, intended to equip ' a motor vehicle of the "RENAULT" brand ("SCENIC" model) are in mm: 185 - 620 - 420 (respectively, envelope width - envelope diameter - rim diameter).
Pour les besoins du test, on a ensuite pratiqué une perforation de 6 mm de diamètre à mi- largeur de la bande de roulement de l'enveloppe incluse dans chaque ensemble monté, radialement à l'intérieur d'un fond de sillon de cette bande de roulement.For the purposes of the test, a perforation of 6 mm in diameter was then made at mid-width of the tread of the envelope included in each mounted assembly, radially inside a groove bottom of this band of rolling.
On a ensuite procédé à des essais successifs de roulage de ces véhicules dont l'un des ensembles montés (avant droit), comportant l'une des compositions lubrifiantes C-l à C-5, roule à plat dès le début de chaque essai en raison de cette perforation préalable.Successive rolling tests were then carried out on these vehicles, one of the mounted assemblies (front right), comprising one of the lubricating compositions Cl to C-5, runs flat at the start of each test due to this prior perforation.
Les conditions particulières de ce roulage à plat étaient pour chaque essai Tes suivantes: charge sur la roue de 450 kg ; vitesse moyenne de roulage de 100 km/h ; température ambiante pour le roulage de 25°C ; roulage sur un circuit de type autoroutier. Le critère d'arrêt de chaque essai est le kilométrage réalisé jusqu'à la destruction de l'appui de sécurité et/ou de l'enveloppe.The specific conditions of this running flat were for each test Tes the following: load on the wheel of 450 kg; average driving speed of 100 km / h; ambient temperature for driving 25 ° C; driving on a motorway-type circuit. The stopping criterion for each test is the mileage carried out until the destruction of the safety support and / or the enclosure.
Les résultats obtenus ont été rapportés dans le tableau 1 ci-dessous.The results obtained are reported in Table 1 below.
Tableau 1Table 1
Ces résultats démontrent clairement la supériorité des compositions selon l'invention C-2 à C-5, comparativement à la composition témoin C-l, chacun des ensembles montés conformes à l'invention parcourant une distance supérieure à 200 km, très nettement améliorée par rapport à l'ensemble monté de l'art antérieur comportant de la glycérine à titre d'agent lubrifiant. These results clearly demonstrate the superiority of the compositions according to the invention C-2 to C-5, compared to the control composition Cl, each of the assembled assemblies in accordance with the invention covering a distance greater than 200 km, very much improved compared to the assembled assembly of the prior art comprising glycerin as a lubricating agent.
Bien entendu, le résultat d'endurance obtenu pour chaque ensemble monté est d'autant meilleur que le kilométrage parcouru est plus élevé et que la masse de composition lubrifiante est plus réduite. De ce point de vue, on note que les meilleurs résultats sont ici obtenus avec les ensembles montés pourvus d'une très faible quantité (60 g par enveloppe) des compositions C-2 et C-3, comportant à titre d'agent lubrifiant un polyoxyalkylène dont la viscosité est comprise dans le domaine préférentiel préconisé de 300 à 700 mPa.s pour des appuis en élastomère diénique.Of course, the endurance result obtained for each assembled assembly is all the better as the mileage covered is higher and the mass of lubricating composition is reduced. From this point of view, it is noted that the best results are obtained here with the assembled assemblies provided with a very small amount (60 g per envelope) of compositions C-2 and C-3, comprising as lubricating agent a polyoxyalkylene whose viscosity is within the preferred range recommended from 300 to 700 mPa.s for supports in diene elastomer.
Essai 2Trial 2
Dans ce second essai, 5 nouvelles compositions lubrifiantes notées C-6 à C-10, conformes ou non à l'invention, sont préparées, présentant un taux variable d'agent épaississantIn this second test, 5 new lubricant compositions denoted C-6 to C-10, whether or not in accordance with the invention, are prepared, having a variable level of thickening agent
(silice "Cabosil M5") comme indiqué dans le tableau 2. Seules les compositions C-7 et C-(silica "Cabosil M5") as indicated in table 2. Only compositions C-7 and C-
8 comportant un taux de silice supérieur à 4,0% et inférieur à 7,5%, sont donc conformes à8 having a silica content greater than 4.0% and less than 7.5%, therefore comply with
• l'invention. • the invention.
Les agents lubrifiants de cet essai sont les produits "Emkarox VG 217W" et "Emkarox VG 379W" utilisés dans l'essai précédent. Dans ces exemples, aucun additif n'a été ajouté aux compositions lubrifiantes qui consistent donc simplement en la combinaison de l'agent plastifiant et de la silice.The lubricants in this test are the products "Emkarox VG 217W" and "Emkarox VG 379W" used in the previous test. In these examples, no additive was added to the lubricant compositions which therefore consist simply of the combination of the plasticizing agent and the silica.
Les compositions ont été testées en roulage à plat comme indiqué précédemment pour l'essai N°l (60 g seulement de composition lubrifiante par enveloppe). Les résultats sont rapportés dans le tableau 2 ci-dessous.The compositions were tested on a flat run as indicated above for test No. 1 (only 60 g of lubricating composition per envelope). The results are reported in Table 2 below.
Tableau 2Table 2
Ces résultats confirment bien ceux de l'essai précédent, à savoir que les compositions selon l'invention (C-7 et C-8) offrent aux ensembles montés une endurance nettement supérieure à 200 km, alors que les compositions C-6 d'une part, C-9 et C-10 d'autre part, montrent comparativement une endurance dégradée, malgré l'emploi, ce qui doit être souligné, d'un agent lubrifiant identique et d'un taux de silice très voisin. These results confirm those of the previous test, namely that the compositions according to the invention (C-7 and C-8) offer the mounted assemblies an endurance clearly greater than 200 km, while the compositions C-6 of on the one hand, C-9 and C-10 on the other hand, show comparatively degraded endurance, despite the use, which must be emphasized, of an identical lubricating agent and a very similar silica content.
En conclusion, les compositions lubrifiantes selon l'invention permettent de conférer aux ensembles montés de l'invention une lubrification et donc une endurance en roulage à plat qui sont nettement améliorées, cela même pour une quantité sensiblement réduite de composition lubrifiante appliquée.In conclusion, the lubricant compositions according to the invention make it possible to give the mounted assemblies of the invention lubrication and therefore endurance in run-flat which are clearly improved, even for a substantially reduced amount of lubricant composition applied.
Ainsi, les ensembles montés de l'invention ont pour caractéristique préférentielle avantageuse de comporter moins de 200 g, plus préferentiellement moins de 150 g de composition lubrifiante. Dans de nombreux cas, comme cela a été démontré dans les exemples de réalisation qui précèdent, la quantité de composition lubrifiante reste même inférieure à 100 g. Thus, the mounted assemblies of the invention have the advantageous preferential characteristic of comprising less than 200 g, more preferably less than 150 g of lubricating composition. In many cases, as has been demonstrated in the preceding embodiment examples, the amount of lubricating composition even remains less than 100 g.

Claims

REVENDICATIONS
1. Composition lubrifiante utilisable pour lubrifier une interface entre une enveloppe de pneumatique et un appui de sécurité monté sur une jante de roue à l'intérieur de ladite enveloppe, caractérisée en ce qu'elle comporte un polyoxyalcène à titre d'agent lubrifiant et, à titre d'agent épaississant, entre 4,0% et 7,5% de silice.1. Lubricating composition which can be used to lubricate an interface between a tire casing and a safety support mounted on a wheel rim inside said casing, characterized in that it comprises a polyoxyalkene as a lubricating agent and, as a thickening agent, between 4.0% and 7.5% silica.
2. Composition selon la revendication 1, le polyoxyalcène étant un polyalcène glycol.2. Composition according to claim 1, the polyoxyalkene being a polyalkene glycol.
3. Composition selon les revendications 1 ou 2, l'alcène étant choisi dans le groupe constitué par éthylène, propylene et butylène.3. Composition according to claims 1 or 2, the alkene being chosen from the group consisting of ethylene, propylene and butylene.
4. Composition selon la revendication 3, le polyoxyalcène étant un copolymère ou un mélange de polymères d'oxyde d'éthylène et d'oxyde de propylene.4. Composition according to claim 3, the polyoxyalkene being a copolymer or a mixture of polymers of ethylene oxide and propylene oxide.
5. Composition selon la revendication 4, dans laquelle le polyoxyalcène est un copolymère d'oxyde d'éthylène et d'oxyde de propylene, ledit copolymère comportant des unités issues de l'oxyde d'éthylène selon une fraction molaire de 40 à 80% et des unités issues de l'oxyde de propylene selon une fraction molaire de 60 à 20%.5. Composition according to claim 4, in which the polyoxyalkene is a copolymer of ethylene oxide and of propylene oxide, said copolymer comprising units derived from ethylene oxide in a molar fraction of 40 to 80% and units derived from propylene oxide in a molar fraction of 60 to 20%.
6. Composition selon l'une quelconque des revendications 1 à 5, le polyoxyalcène ayant une masse moléculaire moyenne en nombre comprise entre 1 000 et 10 000 g/mol, de préférence entre 2 000 et 6 000 g/mol.6. Composition according to any one of claims 1 to 5, the polyoxyalkene having a number average molecular weight of between 1,000 and 10,000 g / mol, preferably between 2,000 and 6,000 g / mol.
7. Composition selon la revendication 6, le polyoxyalcène ayant un indice de polymolécularité inférieur à 1 ,5, de préférence inférieur à 1 ,3.7. Composition according to claim 6, the polyoxyalkene having a polymolecularity index of less than 1.5, preferably less than 1.3.
8. Composition selon l'une quelconque des revendications 1 à 7, le polyoxyalcène ayant une viscosité apparente (mesurée selon norme européenne EN ISO 2555) comprise entre 100 et 1500 mPa.s.8. Composition according to any one of claims 1 to 7, the polyoxyalkene having an apparent viscosity (measured according to European standard EN ISO 2555) of between 100 and 1500 mPa.s.
9. Composition selon la revendication 8, le polyoxyalcène ayant une viscosité apparente comprise entre 200 et 1000 mPa.s.9. Composition according to claim 8, the polyoxyalkene having an apparent viscosity of between 200 and 1000 mPa.s.
10. Composition selon la revendication 9, le polyoxyalcène ayant une viscosité apparente comprise dans un domaine de 450 à 850 mPa.s.10. Composition according to claim 9, the polyoxyalkene having an apparent viscosity comprised in a range from 450 to 850 mPa.s.
11 Composition selon la revendication 9, le polyoxyalcène ayant une viscosité apparente comprise dans un domaine de 300 à 700 mPa.s.11 Composition according to claim 9, the polyoxyalkene having an apparent viscosity comprised in a range from 300 to 700 mPa.s.
12. Composition selon la revendication 11, le polyoxyalcène ayant une viscosité apparente comprise dans un domaine de 400 à 650 mPa.s. 12. Composition according to claim 11, the polyoxyalkene having an apparent viscosity comprised in a range from 400 to 650 mPa.s.
13. Composition selon l'une quelconque des revendications 1 à 12, la fraction massique de silice étant comprise dans un domaine de 5,3% à 6,7%.13. Composition according to any one of claims 1 to 12, the mass fraction of silica being within a range of 5.3% to 6.7%.
14. Composition selon la revendication 13, la fraction massique de silice étant comprise dans un domaine de 5,5% à 6,5%.14. Composition according to claim 13, the mass fraction of silica being within a range of 5.5% to 6.5%.
15. Composition selon la revendication 14, la fraction massique de silice étant égale à environ 6,0%.15. Composition according to claim 14, the mass fraction of silica being equal to approximately 6.0%.
16. Composition selon l'une quelconque des revendications 1 à 9, la silice ayant une surface spécifique BET inférieure à 450 m2/g.16. Composition according to any one of claims 1 to 9, the silica having a BET specific surface of less than 450 m 2 / g.
17. Composition selon la revendication 16, la silice ayant une surface spécifique BET comprise entre 50 et 350 m2/g.17. Composition according to claim 16, the silica having a BET specific surface of between 50 and 350 m 2 / g.
18. Composition selon la revendication 17, la silice ayant une surface spécifique BET comprise entre 100 et 250 m2/g.18. Composition according to claim 17, the silica having a BET specific surface of between 100 and 250 m 2 / g.
19. Composition selon l'une quelconque des revendications 1 à 18, la silice étant une silice pyrogénée.19. Composition according to any one of claims 1 to 18, the silica being a fumed silica.
20. Enveloppe de pneumatique comportant une face radialement interne destinée à faire face à une jante de roue sur laquelle elle est destinée à être montée, caractérisée en-ce que ladite face radialement interne est pourvue d'une composition lubrifiante selon l'une quelconque des revendications 1 à 19.20. A tire covering comprising a radially internal face intended to face a wheel rim on which it is intended to be mounted, characterized in that said radially internal face is provided with a lubricating composition according to any one of claims 1 to 19.
21. Ensemble monté pour véhicule automobile comportant une jante, un appui de sécurité qui est monté sur ladite jante et dont au moins la face radialement externe est constituée d'une composition de caoutchouc ou d'une matière plastique, et une enveloppe de pneumatique montée sur ladite jante autour dudit appui, la jante présentant en chacun de ses deux bords périphériques un siège de jante sur lequel est monté un bourrelet de ladite enveloppe, ladite jante comportant entre ses deux sièges une portée' recevant ledit appui, caractérisé en ce que ledit ensemble monté est pourvu d'une composition lubrifiante selon l'une quelconque des revendications 1 à 19, destinée à lubrifier l'interface enveloppe/ appui de sécurité.21. Mounted assembly for a motor vehicle comprising a rim, a safety support which is mounted on said rim and of which at least the radially outer face is made of a composition of rubber or of a plastic material, and a tire casing mounted on said rim around said support, the rim having on each of its two peripheral edges a rim seat on which is mounted a bead of said casing, said rim comprising between its two seats a bearing surface 'receiving said support, characterized in that said mounted assembly is provided with a lubricating composition according to any one of claims 1 to 19, intended to lubricate the envelope / safety support interface.
22. Ensemble monté selon la revendication 21, caractérisé en ce qu'il est pourvu 'de ladite composition lubrifiante sur la face radialement interne de ladite enveloppe qui- fait face à ladite jante.22. Mounted assembly according to claim 21, characterized in that it is provided with said lubricating composition on the radially internal face of said casing which faces said rim.
23. Ensemble monté selon les revendications 21 ou 22, caractérisé en ce qu'au moins la face radialement externe dudit appui comporte une composition de caoutchouc à base d'élastomère diénique, de préférence du caoutchouc naturel, ou d'élastomère polyuréthanne.23. An assembly assembled according to claims 21 or 22, characterized in that at least the radially external face of said support comprises a rubber composition based diene elastomer, preferably natural rubber, or polyurethane elastomer.
24. Ensemble monté selon les revendications 21 ou 22, caractérisé en ce qu'au moins la face radialement externe dudit appui comporte une composition de caoutchouc à base de polyuréthanne thermodurcissable (TPU) ou d'un élastomère thermoplastique (TPE).24. Mounted assembly according to claims 21 or 22, characterized in that at least the radially outer face of said support comprises a rubber composition based on thermosetting polyurethane (TPU) or a thermoplastic elastomer (TPE).
25. Ensemble monté selon l'une quelconque des revendications 21 à 25, caractérisé en ce qu'il contient moins de 200 g de composition lubrifiante.25. Mounted assembly according to any one of claims 21 to 25, characterized in that it contains less than 200 g of lubricating composition.
26. Ensemble monté selon la revendication 25, caractérisé en ce qu'il contient moins de 150 g de composition lubrifiante.26. Mounted assembly according to claim 25, characterized in that it contains less than 150 g of lubricating composition.
27. Ensemble monté selon la revendication.26, caractérisé en ce qu'il contient moins de 100 g de composition lubrifiante. -27. Mounted assembly according to claim.26, characterized in that it contains less than 100 g of lubricating composition. -
28. Utilisation d'une composition lubrifiante selon l'une quelconque des revendications 1 à 19, pour lubrifier une interface entre une enveloppe de pneumatique pour véhicule automobile, et un appui de sécurité monté sur une jante de roue à l'intérieur de ladite enveloppe. 28. Use of a lubricating composition according to any one of claims 1 to 19, for lubricating an interface between a tire casing for a motor vehicle, and a safety support mounted on a wheel rim inside said casing. .
EP04707202A 2003-02-04 2004-02-02 Lubricating composition for a tyre safety support Withdrawn EP1601540A1 (en)

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CN100528613C (en) 2009-08-19
US20060016535A1 (en) 2006-01-26
CN1747845A (en) 2006-03-15
JP2006518782A (en) 2006-08-17
WO2004069565A1 (en) 2004-08-19
KR20050097978A (en) 2005-10-10

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