Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
• • 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
• • 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
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L21/00—Compositions of unspecified rubbers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L45/00—Compositions of homopolymers or copolymers of compounds having no unsaturated aliphatic radicals in side chain, and having one or more carbon-to-carbon double bonds in a carbocyclic or in a heterocyclic ring system; Compositions of derivatives of such polymers

Definitions

• the invention relates to compositions, in particular for tires and more particularly to compositions comprising a specific hydrocarbon resin for improving the compatibility of the resin with elastomers, in particular with elastomers of very low glass transition temperature (Tg). .
• low Tg elastomers allow an improvement in abrasion performance (WO 2015/043902).
• these low Tg elastomers have a low compatibility with the hydrocarbon resins, plasticizers, usually used in tires, which does not allow to use them easily and optimally in tire compositions that may present the best compromise between performance. difficult to combine at the same time, such as wear resistance, adhesion, which must be high and rolling resistance which must be low in order to minimize fuel consumption.
• WO 2013/176712 discloses various cyclopentadiene / dicyclopentadiene / methylcyclopentadiene type resins having specific masses and softening points. In this document, these resins are used at a rate of 12 phr in the examples to improve the adhesion on wet ground.
• compositions having high adhesion and low rolling resistance.
• the invention therefore relates to a rubber composition based on at least one elastomer, a reinforcing filler, a crosslinking system and a hydrocarbon resin, optionally hydrogenated, mainly composed of units chosen from the group consisting of cyclopentadiene. , dicyclopentadiene, methylcyclopentadiene and mixtures thereof, said hydrocarbon resin having an average molecular weight Mz of less than 2000 g / mol and a glass transition temperature Tg, expressed in ° C such that: Tg ⁇ 80 - 2 * (% HA)
• the level of said hydrocarbon resin is in a range from 15 to 150 phr.
• the invention preferably relates to a composition as defined above wherein said hydrocarbon resin has an Mz of less than 1500 g / mol.
• said hydrocarbon resin has a glass transition temperature Tg, expressed in ° C such that Tg ⁇ 85 - 2 * (% HA).
• said hydrocarbon resin has a polymolecularity index (Ip) of less than 1.7, preferably less than 1.6.
• the resin has an aromatic proton content of less than 50%, preferably in a range from 0% to 20%, preferably from 0% to 15%.
• the resin has an aromatic proton content of less than 5%, preferably in a range from 0% to 4%, preferably from 0% to 2%, and more preferably from 0%.
• the resin has an aromatic proton content ranging from 3% to 15%, preferably from 5% to 10%. Also preferably, the resin has an ethylenic proton content of less than 0.5%, preferably less than 0.1%. More preferably, the resin does not comprise an ethylenic unit.
• the invention relates to a composition as defined above in which the elastomer comprises predominantly an elastomer having a glass transition temperature Tg lower than -70 ° C, preferably between -70 ° C and - 1 10 ° C, more preferably between -80 ° C and -1 10 ° C, and more preferably still between -90 ° C and -1 10 ° C.
• Tg glass transition temperature
• the elastomer comprises predominantly an elastomer is selected from the group consisting of essentially unsaturated diene elastomers, preferably selected from the group consisting of polybutadienes, butadiene copolymers and mixtures of these elastomers, and more preferably in the group consisting of polybutadienes, butadiene and styrene copolymers and mixtures of these elastomers.
• the invention relates to a composition as defined above in which the reinforcing filler is selected from the group consisting of silicas, carbon blacks and mixtures thereof.
• the level of reinforcing filler is in a range from 5 to 200 phr, preferably from 40 to 160 phr.
• the The majority reinforcing filler is silica, preferably at a rate in a range from 40 to 150 phr.
• the composition additionally comprises, as a minor fraction, carbon black, preferably at a level within a range of from 0.1 to 10 phr.
• the invention relates to a composition as defined above wherein the level of said hydrocarbon resin is in a range from 25 to 120 phr, preferably from 40 to 1 phr.
• the invention also relates to a tire comprising a composition as defined above, preferably in all or part of its tread.
• the tire according to the invention will be selected from tires intended to equip a two-wheeled vehicle, a passenger vehicle, or a vehicle called “heavyweight” (that is to say, subway, bus , off-the-road vehicles, road transport vehicles such as trucks, tractors, trailers), or aircraft, civil engineering, agrarian, or handling equipment.
• a two-wheeled vehicle a passenger vehicle
• a vehicle called “heavyweight” that is to say, subway, bus , off-the-road vehicles, road transport vehicles such as trucks, tractors, trailers
• aircraft civil engineering, agrarian, or handling equipment.
• the rubber compositions according to the invention are based on at least one elastomer, a reinforcing filler, a crosslinking system and a hydrocarbon resin, optionally hydrogenated, predominantly composed of units selected from the group consisting of cyclopentadiene. , dicyclopentadiene, methylcyclopentadiene and mixtures thereof, said hydrocarbon resin having an average molecular weight Mz of less than 2000 g / mol and a glass transition temperature Tg, expressed in ° C such that:
• the level of said hydrocarbon resin is in a range from 15 to 150 phr (parts by weight per hundred parts by weight of elastomer).
• composition based on is meant a composition comprising the mixture and / or the reaction product in situ of the various basic constituents used, some of these constituents being able to react and / or being intended to react. between them, at least partially, during the various phases of manufacture of the composition, or during the subsequent firing, modifying the composition as it is prepared at the start.
• the compositions as implemented for the invention may be different in the uncrosslinked state and in the crosslinked state.
• any range of values designated by the expression "between a and b" represents the range of values from more than a to less than b (i.e. terminals a and b excluded) while any range of values designated by the term “from a to b” means the range from a to b (i.e., including the strict limits a and b).
• a majority compound is the polymer representing the largest mass relative to the total mass of the polymers in the composition.
• a so-called majority charge is that representing the largest mass among the charges of the composition.
• a "minor" compound is a compound that does not represent the largest mass fraction among compounds of the same type.
• a resin mainly composed of cyclopentadiene units is a resin in which the cyclopentadiene units represent the largest quantity by mass, among all the units composing said resin.
• a resin predominantly composed of units selected from the group consisting of cyclopentadiene, dicyclopentadiene, methylcyclopentadiene and mixtures thereof is a resin in which the sum of units selected from the group consisting of cyclopentadiene, dicyclopentadiene, methylcyclopentadiene and mixtures thereof, represent the largest number by mass among all the units comprising said resin.
• a "majority" monomer is a monomer that represents the largest mass fraction in the polymer.
• a “minor” monomer is a monomer that does not represent the largest mole fraction in the polymer.
• the elastomer may be selected from the group consisting of diene elastomers and mixtures thereof.
• elastomer or "rubber”, the two terms being considered synonymous
• the two terms being considered synonymous
• elastomer at least in part (ie, a homopolymer or copolymer) of diene monomers (monomers bearing two carbon-carbon double bonds, conjugated or otherwise).
• the diene elastomers can be classified in two categories: "essentially unsaturated” or “essentially saturated”.
• the term "essentially unsaturated” is generally understood to mean a diene elastomer derived at least in part from conjugated diene monomers, having a level of units or units of diene origin (conjugated dienes) which is greater than 15% (mol%);
• diene elastomers such as butyl rubbers or copolymers of dienes and alpha-olefins of the EPDM type do not fall within the above definition and may in particular be described as "essentially saturated” diene elastomers ( low or very low diene origin, always less than 15%).
• the term “highly unsaturated” diene elastomer is particularly understood to mean a diene elastomer having a content of units of diene origin (conjugated dienes) which is greater than 50%.
• diene elastomer any type of diene elastomer
• the person skilled in the art of the tire will understand that the present invention is preferably implemented with essentially unsaturated diene elastomers, in particular of the type (a) or (b) above.
• conjugated dienes 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di (C 1 -C 5) -alkyl-1,3-butadienes, such as for example 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl 1,3-butadiene, rary-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene.
• Suitable vinylaromatic compounds are, for example, styrene, ortho-, meta-, para-methylstyrene, the "vinyl-toluene" commercial mixture, para-tert-butylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene.
• the copolymers may contain between 99% and 20% by weight of diene units and between 1% and 80% by weight of vinylaromatic units.
• the elastomers may have any microstructure which is a function of the polymerization conditions used, in particular the presence or absence of a modifying and / or randomizing agent and the amounts of modifying and / or randomizing agent used.
• the elastomers can be for example block, statistical, sequenced, microsequenced, and be prepared in dispersion or in solution; they may be coupled and / or starred or functionalized with a coupling agent and / or starring or functionalization.
• function is meant here preferably a chemical group interactive with the reinforcing filler of the composition.
• the diene elastomer of the composition is preferably chosen from the group of highly unsaturated diene elastomers consisting of polybutadienes (abbreviated "BR"), synthetic polyisoprenes (IR), natural rubber (NR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers.
• BR polybutadienes
• IR synthetic polyisoprenes
• NR natural rubber
• butadiene copolymers isoprene copolymers and mixtures of these elastomers.
• SBR butadiene-styrene copolymers
• the invention preferably relates to compositions in which the elastomer said diene elastomer is selected from the group consisting of essentially unsaturated diene elastomers, and in particular in the group consisting of polybutadienes, synthetic polyisoprenes, natural rubber, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.
• the elastomer comprises predominantly an elastomer, preferably diene, having a glass transition temperature Tg lower than -70 ° C, preferably between -70 ° C and -1-10 ° C. ° C. More preferably, the elastomer comprises predominantly an elastomer having a glass transition temperature Tg of between -80 ° C and -110 ° C, preferably between -90 ° C and -110 ° C.
• the majority diene elastomer is chosen from the group consisting of polybutadienes, butadiene copolymers and mixtures of these elastomers, and more preferentially from the group consisting of polybutadienes, butadiene and styrene copolymers. and mixtures of these elastomers.
• the majority elastomer of very low Tg preferably diene
• the composition comprises 100 phr of elastomer of very low Tg as defined above.
• the composition according to the invention comprises a reinforcing filler. It is possible to use any type of reinforcing filler known for its ability to reinforce a rubber composition which can be used for the manufacture of tires, for example an organic filler such as carbon black, a reinforcing inorganic filler such as silica, alumina, or a blend of these two types of filler.
• a reinforcing filler known for its ability to reinforce a rubber composition which can be used for the manufacture of tires, for example an organic filler such as carbon black, a reinforcing inorganic filler such as silica, alumina, or a blend of these two types of filler.
• carbon blacks are suitable all carbon blacks, including so-called pneumatic grade blacks.
• the reinforcing carbon blacks of the 100, 200 or 300 series for example blacks N 15, N 134, N 234, N 326, N330, N 339, N 347 or N375, or else, according to the targeted applications, the blacks of higher series (for example N660, N683, N772).
• the carbon blacks could for example already be incorporated into an isoprene elastomer in the form of a masterbatch (see for example WO 97/36724 or WO 99/16600).
• organic fillers other than carbon blacks
• the composition may contain a type of silica or a blend of several silicas.
• the silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or fumed silica having a BET surface and a CTAB specific surface both less than 450 m 2 / g, preferably from 30 to 400 m 2 / boy Wut.
• HDS highly dispersible precipitated silicas
• the silica preferably has a BET surface area of between 45 and 400 m 2 / g, more preferably between 60 and 300 m 2 / g.
• compositions may optionally also contain, in addition to the coupling agents, coupling activators, inorganic charge-covering agents or, more generally, processing aid agents which can be used in a known manner, thanks to a improving the dispersion of the filler in the rubber matrix and lowering the viscosity of the compositions, to improve their ability to use in the green state, these agents being, for example, hydrolysable silanes such as alkylalkoxysilanes, polyols, fatty acids, polyethers, primary, secondary or tertiary amines, hydroxylated or hydrolysable polyorganosiloxanes.
• hydrolysable silanes such as alkylalkoxysilanes, polyols, fatty acids, polyethers, primary, secondary or tertiary amines, hydroxylated or hydrolysable polyorganosiloxanes.
• Polysulphurized silanes called “symmetrical” or “asymmetrical” according to their particular structure, are used, for example, as described for example in the applications WO03 / 002648 (or US 2005/016651) and WO03 / 002649 (or US 2005 / 016650).
• x is an integer of 2 to 8 (preferably 2 to 5);
• A is a divalent hydrocarbon radical (preferably C 1 -C 18 alkylene groups or C 6 -C 12 arylene groups, more particularly C 1 -C 10 alkylenes, in particular C 1 -C 4 alkylenes, in particular propylene);
• R2 R2 in which:
• the radicals R2 substituted or unsubstituted, identical or different from each other, represent a C 1 -C 18 alkoxyl or C 5 -C 18 cycloalkoxyl group (preferably a group chosen from C 1 -C 8 alkoxyls and C 5 -C 8 cycloalkoxyls, plus preferably still another group chosen from C 1 -C 4 alkoxyls, in particular methoxyl and ethoxyl).
• polysulphurized silanes By way of examples of polysulphurized silanes, mention may be made more particularly of polysulphides (especially disulfides, trisulphides or tetrasulfides) of bis (C 1 -C 4 alkoxyl) -alkyl (C 1 -C 4) alkyl-silyl (C 1 -C 4) )), such as, for example, bis (3-trimethoxysilylpropyl) or bis (3-triethoxysilylpropyl) polysulfides.
• polysulphides especially disulfides, trisulphides or tetrasulfides
• TESPT bis (3-triethoxysilylpropyl) tetrasulfide
• TESPD bis (3-triethoxysilylpropyl) tetrasulfide
• the content of coupling agent is preferably between 1 and 15 phr, more preferably between 3 and 14 phr.
• the physical state in which the reinforcing filler is present is indifferent, whether in the form of powder, microbeads, granules, beads or any other suitable densified form.
• the total reinforcing filler content (carbon black and / or reinforcing inorganic filler such as silica) is 5 to 200 phr, more preferably from 40 to 160 phr. Below 5 phr of load, the composition may not be sufficiently reinforced while above 200 phr of the load, the composition may be less effective in rolling resistance.
• silica is used as the predominant filler, preferably at a level ranging from 40 to 150 phr, more preferably from 90 to 150 phr; and optionally carbon black.
• Carbon black when present, is used in a minority manner, preferably at a level within a range from 0.1 to 10 phr, more preferably from 0.5 to 10 phr, especially from 1 to 5 phr. pc.
• composition of the invention one can use any type of crosslinking system known to those skilled in the art for rubber compositions.
• the crosslinking system is a vulcanization system, that is to say based on sulfur (or a sulfur donor agent) and a primary vulcanization accelerator.
• a primary vulcanization accelerator to say based on sulfur (or a sulfur donor agent) and a primary vulcanization accelerator.
• sulfur or a sulfur donor agent
• a primary vulcanization accelerator to say a sulfur donor agent
• various known secondary accelerators or vulcanization activators such as zinc, stearic acid or equivalent compounds, guanidine derivatives (in particular diphenylguanidine).
• Sulfur is used at a preferential rate of between 0.5 and 10 phr, more preferably between 0.5 and 5 phr, in particular between 0.5 and 3 phr.
• the vulcanization system of the composition according to the invention may also comprise one or more additional accelerators, for example the compounds of the thiuram family, zinc dithiocarbamate derivatives, sulfenamides, guanidines or thiophosphates.
• additional accelerators for example the compounds of the thiuram family, zinc dithiocarbamate derivatives, sulfenamides, guanidines or thiophosphates.
• any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur in particular thiazole type accelerators and their derivatives, thiuram type accelerators, zinc dithiocarbamates, may be used in particular.
• accelerators are more preferably selected from the group consisting of 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS”), N-cyclohexyl-2-benzothiazyl sulfenamide (abbreviated “CBS”), N, N-dicyclohexyl-2-benzothiazyl sulfenamide (abbreviated “DCBS”), N-tert-butyl-2-benzothiazyl sulfenamide (abbreviated “TBBS”), N-tert-butyl-2-benzothiazylsulfenimide (abbreviated "TBSI”), zinc dibenzyldithiocarbamate (abbreviated as "ZBEC”) and mixtures of these compounds.
• MBTS 2-mercaptobenzothiazyl disulfide
• CBS N-cyclohexyl-2-benzothiazyl sulfenamide
• DCBS N-dicyclohe
• composition according to the invention comprises a specific hydrocarbon resin.
• This hydrocarbon resin is mainly composed of units selected from the group consisting of cyclopentadiene, dicyclopentadiene, methylcyclopentadiene and mixtures thereof.
• the hydrocarbon resin useful for the purposes of the invention has an aromatic proton content of less than 50%, preferably in a range from 0% to 20%, preferably from 0% to 15%.
• the hydrocarbon resin useful for the purposes of the invention has an aromatic proton content of less than 5%, preferably in a range from 0% to 4%, preferably 0%. at 2%, preferably 0%.
• the hydrocarbon resin useful for the purposes of the invention has an aromatic proton content in a range from 3% to 15%, preferably from 5% to 10%.
• the hydrocarbon resin useful for the purposes of the invention has an ethylenic proton content of less than 0.5%, preferably less than 0.1%. More preferably, the resin does not comprise an ethylenic unit.
• the hydrocarbon resin useful for the purposes of the invention has an average molecular weight Mz of less than 2000 g / mol, preferably less than 1500 g / mol.
• the hydrocarbon resin useful for the purposes of the invention has a glass transition temperature Tg, expressed in ° C such that Tg ⁇ 80 - 2 * (% HA) - where% HA represents the aromatic proton content of said resin - preferably such that Tg ⁇ 85 - 2 * (% HA).
• Tg is measured according to ASTM D3418 (1999).
• the hydrocarbon resin useful for the purposes of the invention has a polymolecularity index (Ip) of less than 1, 7, preferably less than 1, 6.
• hydrocarbon resins In commerce, there are many hydrocarbon resins available. These resins may have characteristics, including chemical composition, Mz, Tg, aromatic proton levels or Ip, which differ from one supplier to another.
• the macrostructure (Mw, Mn, Ip and Mz) of the hydrocarbon resin is determined by steric exclusion chromatography (SEC) on the basis of ISO 16014 standards (Determination of average molecular mass and molecular mass distribution of polymers using size exclusion chromatography), ASTM D5296 (Molecular Weight Averages and molecular weight distribution of polystyrene by High performance size exclusion chromatography), and DIN 55672 (size exclusion chromatography).
• the resin sample is solubilized in non-antioxidized tetrahydrofuran to a concentration of 1.5 g / l.
• the solution is filtered with a Teflon filter with a porosity of 0.45 ⁇ , for example using a disposable syringe fitted with a filter.
• a volume of 100 ⁇ is injected through a set of size exclusion chromatography columns.
• the mobile phase is eluted with a flow rate of 1 ml / min.
• the columns are thermostatically controlled in an oven at 35 ° C.
• the detection is ensured by a refractometer thermostated at 35 ° C.
• the stationary phase of the columns is based on a divinylbenzene polystyrene gel with controlled porosity.
• the polymer chains are separated according to the size they occupy when they are solubilized in the solvent: the more they occupy a large volume, the less accessible the pores of the columns and their elution time is low.
• polystyrene standards with narrow molecular distributions are used for the calibration curve.
• the molar mass range of these standards ranges from 160 to about 70,000 g / mol.
• These standards can be grouped by "families" of 4 or 5 standards having an increment of approximately 0.55 in log of M between each.
• the average molar masses in number (Mn), in mass (Mw), the Mz, and the polydispersity of the analyzed resin are calculated from this calibration curve. This is why we speak of molar masses relative to a polystyrene calibration.
• Ip Mw / Mn with Mw weight average molecular weight, and Mn molecular mass by number. It is also recalled that the masses Mw, Mn and Mz are average masses calculated according to the formulas below:
• Ai is the amplitude of the signal of the refractometric detector corresponding to the mass Mi and to the elution time ti.
• the material used for the SEC measurement is a liquid chromatography chain, for example the WATERS Alliance 2690 chain comprising a pump, a degasser and an injector; a differential refractometer (for example the WATERS refractometer 2410), data acquisition and processing software, for example the WATERS WATOWER software, a column oven, for example the WATERS "columns Heater Module” and 4 mounted columns in series in the following order:
• the aromatic proton level (% HA) and the ethylene proton content (% HE) are measured by 1 H NMR. This determination is made with respect to all the detected signals. Thus, the results obtained are expressed as% peak area.
• the samples are solubilized in deuterated chloroform (CDCl3) at a rate of about 10 mg of resin in about 1 ml of solvent.
• the spectra are acquired on a Bruker 500 MHz Avance spectrometer equipped with a Bruker BBO z-grad 5 mm broadband probe.
• the 1 H NMR experiment uses a 30 ° single pulse sequence and a 5 second repetition time between each acquisition. 64 accumulations are performed at room temperature. The chemical shifts are calibrated with respect to the protonated impurity of deuterated chloroform; 1 ppm at 7.20 ppm.
• the 1 H NMR signals of the aromatic protons are between 8.5ppm and 6.2ppm. Ethylenic protons generate signals between 6.2ppm and 4.5ppm. Finally, the signals corresponding to the aliphatic protons are located between 4.5ppm and Oppm.
• the areas of each category of protons are referred to the sum of these areas to give a distribution in% of area of each category
• the resin useful for the purposes of the invention mainly composed of units selected from the group consisting of cyclopentadiene, dicyclopentadiene, methylcyclopentadiene and mixtures thereof, may comprise, in addition to these units, and a minority, aliphatic units, or aromatic or aliphatic / aromatic type that is to say based on aliphatic and / or aromatic monomers.
• Suitable aromatic monomers are styrene, alpha-methylstyrene, ortho-, meta-, para-methylstyrene, vinyl-toluene, para-tertiarybutylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene, indene, any vinylaromatic monomer from a C9 cut (or more generally from a C8 to C10 cut).
• the vinylaromatic monomer is styrene or a vinylaromatic monomer derived from a C9 cut (or more generally from a C8 to C10 cut).
• the resin useful for the purposes of the invention is selected from the group consisting of homopolymer resins of cyclopentadiene, dicyclopentadiene, or methylcyclopentadiene and mixtures thereof, or copolymer resins consisting of monomers selected from the group consisting of cyclopentadiene, dicyclopentadiene, methylcyclopentadiene and mixtures thereof, and mixtures of these copolymeric resins.
• the resin useful for the purposes of the invention may be a mixture of the aforementioned monomeric or copolymeric resins.
• the resin useful for the purposes of the invention is selected from the group consisting of resins mainly composed of units selected from the group consisting of cyclopentadiene, dicyclopentadiene, methylcyclopentadiene and minorotarily, aromatic units or the aliphatic / aromatic type, and mixtures thereof.
• the level of resin in the composition according to the invention is in a range from 15 phr to 150 phr, preferably 25 to 120 phr, more preferably 40 to 1 phr, even more preferably 50 to 1 phr. 10 pce, better from 65 to 1 10 pce. Indeed, below 15 phr of the resin useful for the purposes of the invention, the effect of the resin would not be sufficient and the composition could have adhesion problems, while above 150 phr the composition could present a manufacturing difficulty to easily incorporate all the resin in the composition.
• the rubber compositions according to the invention optionally also include all or part of the usual additives usually used in elastomer compositions intended in particular for the manufacture of treads, such as for example pigments, protective agents such as anti-ozone waxes, chemical antiozonants, anti-oxidants, plasticizers other than those previously described, anti-fatigue agents, reinforcing resins, acceptors (for example phenolic novolac resin) or methylene donors (for example HMT or H3M).
• the composition according to the invention may also comprise a plasticizer system. This plasticizer system may be composed of a hydrocarbon resin of Tg greater than 20 ° C, in addition to the specific hydrocarbon resin described above, and / or a plasticizing oil.
• compositions according to the invention can be used alone or in cutting (i.e., mixed) with any other rubber composition used for the manufacture of tires.
• the invention relates to the previously described rubber compositions both in the so-called “raw” or uncrosslinked state (ie, before cooking) in the so-called “cooked” or crosslinked state, or still vulcanized (ie, after crosslinking or vulcanization).
• compositions are manufactured in appropriate mixers, using two successive preparation phases well known to those skilled in the art: a first phase of work or thermomechanical mixing (sometimes called “non-productive” phase) to high temperature, up to a maximum temperature of between 1 10 ° C and 200 ° C, preferably between 130 ° C and 180 ° C, followed by a second phase of mechanical work (sometimes referred to as "productive" phase) to lower temperature, typically less than 1 10 ° C, for example between 60 ° C and 100 ° C, finishing phase during which is incorporated the crosslinking system or vulcanization; such phases have been described, for example, in EP-A-0501227, EP-A-0735088, EP-A-0810258, WO00 / 05300 or WO00 / 05301.
• the first phase is preferably carried out in several thermomechanical steps.
• a first step the elastomers, the reinforcing fillers, the hydrocarbon resin (and optionally the coupling agents and / or other ingredients with the exception of the above) are introduced into a suitable mixer such as a conventional internal mixer. of the crosslinking system) at a temperature between 20 ° C and 100 ° C and preferably between 25 ° C and 100 ° C.
• the other ingredients ie, those that remain if all were not put initially
• the total mixing time in this non-productive phase is preferably between 2 and 10 minutes at a temperature less than or equal to 180 ° C, and preferably less than or equal to 170 ° C.
• the low temperature crosslinking system typically less than 100 ° C
• an external mixer such as a roll mill
• the whole is then mixed (productive phase) for a few minutes, for example between 5 and 15 min.
• the final composition thus obtained is then calendered, for example in the form of a sheet or a plate, in particular for a characterization in the laboratory, or extruded, for example to form a rubber profile used for the manufacture. of semi-finished tires.
• These products can then be used for the manufacture of tires, according to techniques known to those skilled in the art, with the advantage of the invention, namely a good sticky layers on each other before baking the tire.
• the crosslinking (or baking) is conducted in a known manner at a temperature generally between 130 ° C and 200 ° C, under pressure, for a sufficient time which may vary for example between 5 and 90 min depending in particular on the cooking temperature, the crosslinking system adopted, the kinetics of crosslinking of the composition in question or the size of the tire.
• the rubber compositions are characterized before and / or after cooking as indicated below. Dynamic properties (after cooking):
• the dynamic properties G * and tan (5) max are measured on a viscoanalyzer (Metravib V A4000), according to the ASTM D 5992 - 96 standard.
• the response of a sample of vulcanized composition (cylindrical specimen of 4) is recorded. mm thick and 10 mm in diameter) subjected to sinusoidal stress in alternating simple shear at a frequency of 10 Hz, during a temperature sweep of -80 ° C to + 100 ° C with a ramp of + 1.5 ° C / min, under a maximum stress of 0.7 MPa.
• the tangent value of the loss angle (Tan delta) is then read at 0 ° C and 60 ° C.
• the results are expressed in performance base 100, that is to say that the value 100 is arbitrarily assigned to the best control, to then compare the tan (5) at 60 ° C. (that is to say the hysteresis - and therefore the rolling resistance) of the different solutions tested.
• the value in base 100 is calculated according to the operation: (value of tan (5) at 60 ° C of the control / value of tan (5) at 60 ° C of the sample) * 100.
• a value lower represents a decrease in hysteresis performance (that is, an increase in hysteresis) while a higher value represents a better hysteresis performance (ie lower hysteresis) ).
• tan (5) 0 ° C For the value of tan (5) 0 ° C, the higher the value, the more the composition will allow good wet adhesion.
• performance base 100 that is to say that the value 100 is arbitrarily assigned to the best control, to calculate and then compare the tan (5) at 0 ° C. of the different solutions tested.
• the value in base 100 is calculated according to the operation: (value of tan (5) at 0 ° C of the sample / value of tan (5) at 60 ° C of the control) * 100.
• a value lower is a decrease in adhesion performance (i.e., a tan value (5) at 0 ° C lower) while a higher value represents a better adhesion performance (ie that is, a tan value (5) at 0 ° C higher).
• compositions are manufactured with an introduction of all the constituents on an internal mixer, with the exception of the vulcanization system.
• Vulcanizing agents sulfur and accelerator
• the constituent cylinders of the mixer being at about 30 ° C).
• Table 2 The examples presented in Table 2 are intended to compare the different rubber properties of control compositions (TO to T7) to the properties of compositions according to the invention (C1 to C4). Properties measured before and after firing are presented in Table 3.
• the composition T0 which does not conform to the invention and which does not include plasticizing resin, has an adhesion (measured by the tan delta value at 0 ° C. ) which is weak and needs improvement.
• the adhesion of this composition therefore serves as a basis for comparing the performance of the other compositions. It is noted that all the compositions comprising a resin make it possible to improve this performance. In contrast, only compositions C1 to C4, and T4 allow more than 60% improvement in adhesion. On the other hand and contrary to the compositions according to the invention (C1 to C4), the composition T4 has a highly degraded hysteresis performance which can not be suitable for the invention.
• compositions C1 to C4 (whose average performance is improved by 25% or more with respect to T0) have a good hysteresis performance (measured by the tan delta value at 60 ° C.), and an improved grip of more than 60%.

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• 2015
  • 2015-10-16 FR FR1559874A patent/FR3042504B1/fr active Active
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