Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/34—Silicon-containing compounds
• • 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
  • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
• • 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
  • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
  • B60C1/0008—Compositions of the inner liner
• • 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
  • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
  • B60C1/0016—Compositions of the tread
• • 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
  • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
  • B60C1/0025—Compositions of the sidewalls
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
  • C08K3/013—Fillers, pigments or reinforcing additives

Definitions

• the present invention relates to diene rubber compositions which can be used for the manufacture of tires or semi-finished products for tires, in particular treads for these tires, as well as to reinforcing fillers capable of reinforcing such rubber compositions.
• a first subject of the invention relates to a rubber composition based on at least (i) a diene elastomer, (ii) an inorganic reinforcing filler, (iii) a coupling agent ensuring the connection between the reinforcing filler and the elastomer, characterized in that said inorganic filler comprises a silicon nitride (hereinafter called "reinforcing silicon nitride”) having the following characteristics: - (a) a BET specific surface area of between 20 and 200 m 2 / g;
• the invention also relates to a process for obtaining a rubber composition which can be used for the manufacture of tires, in which at least one diene elastomer is incorporated, at least one reinforcing inorganic filler and a coupling agent ensuring the connection. between the reinforcing inorganic filler and the elastomer, this process being characterized in that said inorganic filler comprises a silicon nitride having the following characteristics: (a) a BET specific surface area of between 20 and 200 m 2 / g;
• thermomechanically kneaded in one or more stages, until a maximum temperature of between 110 ° C. and 190 ° C. is reached.
• the invention also relates to the use of a composition in accordance with the invention for the manufacture of finished articles or semi-finished products, as well as these finished articles and semi-finished products themselves, comprising a composition of rubber in accordance with the invention, these articles or products being intended for any ground connection system of motor vehicles, such as tires, internal safety supports for tires, wheels, rubber springs, elastomeric joints, other suspension and anti-vibration elements .
• the invention particularly relates to tires comprising an elastomeric composition according to the invention and intended to equip passenger vehicles, 4x4 vehicles (4-wheel drive), SUV ("Sport Utility Vehicles"), two wheels (in particular bicycles or motorcycles), such as industrial vehicles chosen from vans, "Heavy vehicles” - Le., metro, bus, road transport equipment (trucks, tractors, trailers), off-road vehicles, agricultural or civil engineering machinery , airplanes, other transport or handling vehicles.
• 4x4 vehicles (4-wheel drive
• SUV Sport Utility Vehicles
• two wheels in particular bicycles or motorcycles
• industrial vehicles chosen from vans, "Heavy vehicles” - Le., metro, bus, road transport equipment (trucks, tractors, trailers), off-road vehicles, agricultural or civil engineering machinery , airplanes, other transport or handling vehicles.
• the invention relates in particular to tire treads, these treads being able to be used during the manufacture of new tires or for retreading used tires; thanks to the compositions of the invention, these treads have both a low rolling resistance, a very good grip and a high resistance to wear.
• the invention also relates to the use as reinforcing filler, in a diene rubber composition, of a reinforcing silicon nitride as defined above.
• the invention finally relates to a process for reinforcing a diene rubber composition, characterized in that there is incorporated into this composition in the raw state, by thermo-mechanical kneading, a reinforcing silicon nitride as defined above .
• the charges described below consist, in a known manner, of agglomerates of particles, capable of disaggregating into these particles under the effect of an external force, for example under the action of mechanical work or ultrasound.
• particle used in the present application must be understood in its usual generic sense of aggregate (also called “secondary particle”), and not in that of elementary particle (also called “primary particle”) which may form, the if necessary, part of this aggregate; "aggregate” means in a known manner the non-breaking set (ie, which cannot be cut, divided, shared) which is produced during the synthesis of the charge, generally formed of elementary (primary) particles aggregated between they.
• 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” Vol. 60, page 309, February 1938), more precisely according to the French standard NF ISO 9277 of December 1996 [multi-point volumetric method (5 points) - gas: nitrogen - degassing: hour at 160 ° C - relative pressure range p / in: 0.05 to 0.17].
• the average size (by mass) of the particles is measured in a conventional manner after ultrasonic dispersion of the charge to be analyzed in demineralized water.
• the measurement is carried out using a centrifugal sedimentometer with X-ray detection type "XDC” ("X Ray Disc Centrifuge Sedimentometer"), sold by the company Brookhaven Instruments, a known device used in particular for the characterization of silica particles.
• XDC X Ray Disc Centrifuge Sedimentometer
• a suspension of 1 to 4 g (for example 1.7 g is suitable) of load sample to be analyzed is produced in 40 ml of water, per action for 8 minutes, at 60% power (60% of the maximum position of the "output control"), a 1500 W ultrasonic probe (3/4 inch Vibracell sonicator sold by the company Bioblock under the reference M75450).
• the suspension is preferably placed in a cold water bath (for example at a temperature of 5 to 10 ° C).
• the deagglomeration speed (denoted ⁇ ) is measured in the so-called “ultrasonic deagglomeration test” test, at 15% power of a 600 W (watt) probe operating here in pulsed mode (ie 1 second "ON”, 3 seconds “OFF") to avoid overheating of the ultrasonic probe during the measurement.
• This known principle test in particular the subject of patent application WO 99/28376, makes it possible to continuously measure the change in the average size (in volume) of the particle agglomerates during sonication (see WO99 / 28376, WO99 / 28380, WO99 / 28391). Given the very small size of the objects observed, the operating mode was adapted using in this case the Mie method.
• the assembly used consists of a laser granulometer (type "Mastersizer S”, marketed by Malvern Instruments - He-Ne laser source emitting in the red, wavelength 632.8 nm) and its preparer ("Malvern Small Sample Unit MSX1 "), between which was inserted a continuous flow treatment cell (Bioblock M72410) fitted with an ultrasonic probe (1/2 inch sonicator type Vibracell of 600 W sold by the company Bioblock under the reference M72412).
• a quantity of 100 mg of filler to be analyzed is introduced into 30 ml of water.
• the suspension obtained is introduced into the preparer with 130 ml of water, the circulation speed being fixed at its maximum (approximately 3 liters per minute).
• o ie 15% of the maximum position of the "amplitude tip
• a coupling agent white filler / elastomer
• bond which has the function of ensuring the bond or "coupling” between the white filler and the elastomer, while facilitating the dispersion of this inorganic filler within the elastomeric matrix.
• radicals R 2 substituted or unsubstituted, identical or different from each other, represent a C ⁇ -C 18 alkoxyl or C 5 -C 18 cycloalkoxyl group (preferably C ⁇ -C 8 alkoxyl or C 5 -C 8 cycloalkoxyl groups, more preferably Cj alkoxyl groups . -C, in particular methoxyl and / or ethoxyl).
• the optimum rate of coupling agent in moles per square meter of reinforcing inorganic filler for each reinforcing inorganic filler (silicon nitride plus, if applicable, associated additional inorganic filler) used; this optimal rate is calculated from the weight ratio [coupling agent / reinforcing inorganic filler], the BET surface area of the filler and the molar mass of the coupling agent (denoted M below), according to the known relationship next:
• the amount of coupling agent used in the compositions in accordance with the invention is between 10 " 7 and 10" 5 moles per m 2 of reinforcing inorganic filler, or per m 2 of reinforcing silicon nitride when the latter is used without associated reinforcing inorganic filler. Even more preferably, the amount of coupling agent is between 5.10 -7 and 5.10 " 6 moles per square meter of total inorganic charge (silicon nitride plus, where appropriate, associated additional inorganic charge).
• the level of coupling agent, reduced to the weight of diene elastomer will preferably be between 0.1 and 25 phr, more preferably between 0.5 and 20 pc.
• compositions are produced in suitable mixers, using two successive preparation phases well known to those skilled in the art: a first working or thermo-mechanical kneading phase (sometimes called a "non-productive" phase) at high temperature, up to a maximum temperature (noted T max ) of between 110 ° C and 190 ° C, preferably between 130 ° C and 180 ° C, followed by a second phase of mechanical work (sometimes referred to as the "productive" phase) at a lower temperature, typically less than 110 ° C, for example between 60 ° C and 100 ° C, finishing phase during which the crosslinking or vulcanization system is incorporated; such phases have been described for example in applications EP-A-0501227, EP-A-0735088, EP-A-0810258, WO00 / 05300 or WO00 / 05301 mentioned above.
• a first working or thermo-mechanical kneading phase (sometimes called a "non-productive" phase) at high temperature, up to a
• the invention relates to the rubber compositions described above, both in the so-called “raw” state (ie, before baking) and in the so-called “cooked” or vulcanized state (ie, after crosslinking or vulcanization). .
• Load A is tire grade carbon black (N234), conventionally used in tire treads.
• Load B is a coarser carbon black (N550) conventionally used in a tire carcass.
• Filler C is a conventional silica with a high specific surface (BET of around 160 m 2 / g), a reference inorganic filler for reinforcing the treads of "Green Tires” (“Zeosil 1165MP" silica from the company Rhodia).
• the filler D is a reinforcing silicon nitride, that is to say usable in the compositions in accordance with the invention (characteristics a and b verified).
• the filler E is a conventional non-reinforcing silicon nitride. It is commercially available (INTERCHIM company under reference 0429429, lot Kl 1 Jl 1)
• compositions tested below are prepared in a known manner, as follows: the diene elastomer (or the mixture of diene elastomers, if necessary) is introduced into an internal mixer filled to 80%, the initial temperature of which is tank is about 90 ° C; then, after an appropriate mixing time, for example of the order of 30 seconds, all the other ingredients, including the filler and the associated coupling agent, are added, with the exception of the vulcanization system. Thermomechanical work is then carried out for a duration of approximately 16 minutes, with an average speed of the pallets of 70 revolutions / min, until a drop temperature of approximately 140 ° C. is obtained.
• the mixture thus obtained is recovered, it is cooled and then the vulcanization system 0 (sulfur and primary accelerator of the sulfenamide type) is added on an external mixer (homo-finisher) at 30 ° C., mixing the whole (productive phase) for one appropriate time, between 5 and 12 min depending on the case.
• vulcanization system 0 sulfur and primary accelerator of the sulfenamide type
• composition C-1 (control): filler A (carbon black, N234); composition C-2 (control): filler B (carbon black, N550) composition C-3 (control): filler C (silica), with coupling agent (TESPT) - composition C-4: filler in accordance with the invention (Si 3 N), with coupling agent (TESPT) composition C-5 (control): charge E, Si 3 N not in accordance with the invention, with coupling agent (TESPT)
• the carbon black chosen for the control composition C-2 is a tire grade black usually used in a tire carcass.
• silicon nitride is used at iso-volume with respect to carbon black (composition C-1).
• the coupling agent TESPT Si69
• the compositions C-1 and C-2 which serve here as references do not, in known manner, require a coupling agent since they are reinforced with carbon black.
• composition of the invention exhibits, after firing, a level of reinforcement greater than that of the control compositions, with higher modules, in particular with strong deformations (M100 and M250), a ratio M250 / M100 neighbor, significantly higher measurements on the "bound rubber” test, as many reinforcement indices well known to those skilled in the art who are there to attest to the remarkable reinforcing activity of the charge D, in the presence of the coupling agent.
• Figure 2 attached clearly confirms the above observations. Results as remarkable as surprising could not have been foreseen by a person skilled in the art.
• the specific silicon nitride of the composition in accordance with the invention confers on the latter very interesting properties, in particular a remarkable reinforcement capacity and therefore of wear resistance at least equal if not greater than that achieved with carbon black or a conventional HDS silica, hitherto unknown with the silicon nitrides conventionally used in rubber compositions for tires of the prior art.
• the invention thus finds preferential applications in rubber compositions which can be used for the manufacture of tire treads having both a low rolling resistance and a high resistance to wear, in particular when these treads are intended tires for passenger vehicles or for industrial vehicles of the Truck type.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)

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Cited By (65)

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• 2002
  • 2002-07-01 FR FR0208279A patent/FR2841560B1/fr not_active Expired - Fee Related
• 2003
  • 2003-06-27 JP JP2004516714A patent/JP4593272B2/ja not_active Expired - Fee Related
  • 2003-06-27 WO PCT/EP2003/006802 patent/WO2004003067A1/fr not_active Ceased
  • 2003-06-27 AU AU2003245992A patent/AU2003245992A1/en not_active Abandoned
  • 2003-06-27 EP EP03738092A patent/EP1519986A1/fr not_active Withdrawn
• 2004
  • 2004-12-30 US US11/025,081 patent/US7135517B2/en not_active Expired - Fee Related

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