Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L7/00—Compositions of natural rubber
• • 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
  • B60C1/0016—Compositions of the tread
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2312/00—Crosslinking

Definitions

• the present invention relates to rubber compositions intended in particular for the manufacture of tires or semi-finished products for tires.
• the present invention also relates to a finished or semi-finished rubber article comprising a rubber composition according to the invention, as well as a tire comprising at least one composition according to the invention.
• This stiffening can be obtained by increasing the rate of reinforcing filler or by incorporating certain reinforcing resins in the rubber compositions constituting the parts of the tire.
• the reinforcing resins conventionally used to increase the rigidity of the compositions are reinforcing resins based on an acceptor / donor system of methylene.
• the terms “methylene acceptor” and “methylene donor” are well known to those skilled in the art and widely used to denote compounds capable of reacting together to generate by condensation a three-dimensional reinforcing resin which comes to superimpose, interpenetrate with the reinforcing filler / elastomer network on the one hand, with the elastomer / sulfur network on the other hand (if the crosslinking agent is sulfur).
• the methylene acceptor is a phenolic resin.
• Novolak phenolic resins have already been described in rubber compositions, in particular intended for tires or tire treads, for applications as varied as adhesion or reinforcement: reference will be made for example to patent EP 0 649 446 .
• a hardening agent capable of crosslinking or hardening, also commonly called “methylene donor”.
• the crosslinking of the resin is then caused during the curing of the rubber matrix, by formation of methylene bridges between the carbons in ortho and para positions of the phenolic nuclei of the resin and the methylene donor, thus creating a three-dimensional resin network.
• the conventionally used methylene donors are hexamethylene tetramine (abbreviated HMT), or hexamethoxymethylmelamine (abbreviated HMMM or H3M), or hexaethoxymethylmelamine.
• compositions comprising the methylene-acceptor formo-phenolic resin pair with a conventional HMT or H3M hardener methylene donor have been developed.
• application WO 2011/045342 describes compositions comprising an epoxy resin couple with an amine hardener. These compositions, in addition to the advantage of eliminating the formation of formaldehyde, exhibit, after crosslinking, stiffnesses greater than conventional compositions while retaining an acceptable rolling resistance.
• Application WO 2018/002538 describes compositions comprising an epoxy resin and an amine hardener which aims to improve the compromise between processability (in particular toasting time) / rigidity compared to known compositions.
• part by weight per hundred parts by weight of elastomer (or phr), it is understood within the meaning of the present invention, the part, by mass per hundred parts by mass of elastomer or rubber.
• any range of values designated by the expression "between a and b" represents the range of values going from more than a to less than b (ie limits a and b excluded) while any range of values designated by the expression “from a to b” signifies the range of values ranging from a to b (that is to say including the strict limits a and b).
• composition based on is meant a composition comprising the mixture and / or the in situ reaction product of the various constituents used, some of these constituents being able to react and / or being intended to react with each other, less partially, during the different manufacturing phases of the composition; the composition thus being able to be in the fully or partially crosslinked state or in the non-crosslinked state.
• a majority compound it is understood within the meaning of the present invention, that this compound is predominant among the compounds of the same type in the composition, that is to say that it is that which represents the greatest amount by mass among compounds of the same type.
• a majority elastomer is the elastomer representing the largest mass relative to the total mass of the elastomers in the composition.
• a so-called majority charge is that representing the largest mass among the charges of the composition.
• “minority” is a compound which does not represent the largest mass fraction among the compounds of the same type. Preferably, by majority, we mean present at more than 50%, preferably more than 60%, 70%, 80%, 90%, and more preferably the “majority” compound represents 100%.
• the compounds comprising carbon mentioned in the description can be of fossil origin or bio-based. In the latter case, they can be, partially or totally, from biomass or obtained from renewable raw materials from biomass. Are concerned in particular polymers, plasticizers, fillers, etc.
• the composition according to the invention comprises at least one diene elastomer. It can therefore contain a single diene elastomer or a mixture of several diene elastomers.
• diene elastomer or indistinctly rubber, whether natural or synthetic, must be understood in known manner an elastomer consisting at least in part (ie, a homopolymer or a copolymer) of diene monomer units (monomers carrying two carbon-carbon double bonds, conjugated or not).
• diene elastomers can be classified into two categories: “essentially unsaturated” or "essentially saturated”.
• the term "essentially unsaturated” means a diene elastomer derived at least in part from conjugated diene monomers, having a proportion of units or units of diene origin (conjugated dienes) which is greater than 15% (% by moles); This is how diene elastomers such as butyl rubbers or copolymers of dienes and of alpha-olefins of the EPDM type do not enter into the preceding definition and can be qualified in particular as “essentially saturated” diene elastomers (content of motifs of diene origin weak or very weak, always less than 15%).
• the diene elastomers included in the composition according to the invention are preferably essentially unsaturated.
• the other monomer can be ethylene, an olefin or a diene, conjugated or not.
• conjugated dienes having from 4 to 12 carbon atoms are suitable, in particular 1,3-dienes, such as in particular 1,3-butadiene and isoprene.
• olefins suitable are vinyl aromatic compounds having 8 to 20 carbon atoms and aliphatic ⁇ -monoolefins having 3 to 12 carbon atoms.
• vinyl aromatic compounds examples include styrene, ortho-, meta-, para-methylstyrene, the commercial "vinyl-toluene” mixture, para-tert-butylstyrene.
• the acipic aliphatic oc-monoolefins having from 3 to 18 carbon atoms are particularly suitable.
• the diene elastomer is chosen from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), butadiene copolymers, isoprene copolymers, and mixtures of these. elastomers.
• the butadiene copolymers are particularly chosen from the group consisting of butadiene-styrene copolymers (SBR).
• the diene elastomer is an isoprene elastomer.
• isoprene elastomer is understood in known manner an isoprene homopolymer or copolymer, in other words a diene elastomer chosen from the group consisting of natural rubber (NR), synthetic polyisoprenes (IR), different isoprene copolymers and mixtures of these elastomers.
• NR natural rubber
• IR synthetic polyisoprenes
• isoprene copolymers mention will in particular be made of isobutene-isoprene (butyl rubber - HR), isoprene-styrene (SIR), isoprene-butadiene (BIR) or isoprene-butadiene-styrene copolymers (SBIR).
• This isoprene elastomer is preferably chosen from the group consisting of natural rubber, synthetic cis-1,4 polyisoprenes and their mixtures; among these synthetic polyisoprenes are preferably used polyisoprenes having a rate (molar%) of cis-1,4 bonds greater than 90%, more preferably still greater than 98%.
• the diene elastomer is natural rubber.
• the level of diene elastomer preferably isoprene elastomer, preferably natural rubber
• the level of diene elastomer, preferably isoprene elastomer, preferably natural rubber is from 50 to 100 phr, more preferably from 60 to 100 phr, more preferably from 70 to 100 phr, even more preferably from 80 to 100 pce and very preferably 90 to 100 pce.
• the level of diene elastomer, preferably isoprene elastomer, more preferably natural rubber is very preferably 100 phr.
• the rubber composition according to the invention can also contain in a minority any type of synthetic elastomer other than diene, or even polymers other than elastomers, for example thermoplastic polymers.
• the rubber composition according to the invention does not contain a synthetic elastomer other than diene or a polymer other than elastomers or contains less than 10 phr, preferably less than 5 phr.
• the epoxy resins which can be used in the present invention include all the polyepoxide compounds. These can be, for example, aromatic epoxy resins, alicyclic epoxies, and aliphatic epoxies.
• the aromatic epoxy resin may be an amine-aromatic epoxy resin.
• the epoxy resins are preferably novolak epoxy resins, that is to say epoxy resins obtained by acid catalysis, as opposed to resol resins, obtained by basic catalysis.
• the epoxy resins chosen from the group consisting of 2,2 bis [4- (glycidyloxy) phenyl] propane, poly [(o-cresyl glycidyl ether) -co-formaldehyde] are preferred, poly [(phenylglycidyl ether) -co-formaldehyde], poly [(phenylglycidyl ether) -co (hydroxybenzaldehyde glycidyl ether)], aromatic amine epoxy resins and mixtures of these compounds, and preferably the epoxy resins chosen from the group consisting of poly [(o-cresylglycidyl ether) -co-formaldehyde, and poly [(phenylglycidyl ether) -co (hydroxybenzaldehyde glycidyl ether)].
• the epoxy resin is chosen from the group consisting of poly [o-cresylglycidyl ether) -co-formaldehyde], poly [o-phenylglycidyl ether) -co-formaldehyde], aromatic amine epoxy resins and mixtures of these compounds.
• the composition according to the invention comprises between 1 and 30 phr of epoxy resin.
• the rate of epoxy resin is preferably between 10 and 25 phr. More preferably, the level of epoxy resin in the composition according to the invention is between 10 and 20 phr.
• the epoxy resin of the composition of the invention is combined with a particular amine hardener which allows the crosslinking of the resin.
• the amino hardener comprises at least two primary amine functions, located on at least one (that is to say one or more) six-atom aromatic ring, said at least one six-atom aromatic ring comprising:
• At least two radicals Ri identical or different, chosen from the group consisting of linear or branched C1-C6 alkyl radicals, halogens, and ethers, tertiary amines, thioethers, ketones, esters and amides, substituted by linear or branched C1-C6 alkyl radicals,
• the amine hardener comprises one or more aromatic rings with six atoms and at least two primary amine functions, located on one or distributed over several of these aromatic rings with six atoms.
• primary amine function means an amino function in which the nitrogen atom is linked to two hydrogen atoms.
• the amine hardener comprises from 1 to 3, more preferably 1 or 2 aromatic rings with six atoms.
• the amine hardener comprises from 2 to 4, more preferably 2 primary amine functions located on at least one six-atom aromatic ring of the amine hardener.
• halogens capable of constituting the radicals Ri mention may be made of fluorine, chlorine, bromine or iodine atoms.
• the halogens are chosen from the group consisting of chlorine and bromine atoms, more preferably the halogens are chlorine atoms.
• the amine hardener can comprise a six-atom aromatic ring comprising:
• At least two radicals Ri identical or different, chosen from the group consisting of linear or branched C1-C6 alkyl radicals, halogens, and ethers, tertiary amines, thioethers, ketones, esters and amides, substituted by linear or branched C1-C6 alkyl radicals,
• the amine hardener can also comprise at least two aromatic rings with six atoms, identical or different, said cycles each comprising:
• At least one primary amine function • at least one primary amine function, and At least two radicals Ri, identical or different, chosen from the group consisting of linear or branched C1-C6 alkyl radicals, halogens, and ethers, tertiary amines, thioethers, ketones, esters and amides, substituted by linear or branched C1-C6 alkyl radicals,
• the amine hardener can also comprise several aromatic rings with six atoms and at least two primary amine functions located only on one of the aromatic rings.
• these cycles may be the same or different. They may, for example, differ from one another by the nature of the atoms constituting said rings and / or by the number of primary amine functions located on said cycles and / or by the nature and / or the number of radicals Ri placed on said cycles and / or by the position of the primary amine functions and radicals Ri on said cycles.
• the amine hardener comprises several aromatic rings with six atoms, these cycles are identical.
• the amino hardener comprises at least two radicals Ri, identical or different, chosen from the group consisting of linear or branched C1-C6 alkyl radicals, halogens, and ethers, tertiary amines, thio -ethers, ketones, esters and amides, substituted by linear or branched C1-C6 alkyl radicals.
• radicals Ri identical or different, chosen from the group consisting of linear or branched C1-C6 alkyl radicals, halogens, and ethers, tertiary amines, thio -ethers, ketones, esters and amides, substituted by linear or branched C1-C6 alkyl radicals.
• ethers, tertiary amines, thioethers, ketones, esters and amides, substituted by linear or branched C1-C6 alkyl radicals a person skilled in the art understands that the terms "Substituted by linear or branched C1-C6 alkyl radicals” refer to each of the ethers, tertiary amines, thioethers, ketones, esters and amides.
• the amine hardener preferably comprises at least two radicals Ri, identical or different, chosen from the group consisting of linear or branched C1-C6 alkyl radicals, halogens, and ethers , tertiary amines, thioethers, substituted by radicals linear or branched C1-C6 alkyls. More preferably, the amino hardener comprises at least two radicals Ri, identical or different, chosen from the group consisting of linear or branched C1-C6 alkyl radicals, halogens, and thioethers substituted by linear or branched alkyl radicals in C1-C6.
• the radicals Ri are very preferably chosen from the group consisting of linear or branched C1-C6 alkyl radicals.
• all of the radicals R 1 of the amino hardener can be linear or branched C1-C6 alkyl radicals, the linear or branched C1-C6 alkyl radicals being preferably chosen from the group consisting of methyl and ethyl radicals and propyl.
• the at least one aromatic ring with six atoms of the amine hardener may comprise at least two radicals Ri, identical or different, chosen from the group consisting of halogens, and ethers, tertiary amines and thioethers, substituted by linear or branched C1-C6 alkyl radicals, and at least one radical Ri chosen from the group consisting of linear or branched C1-C6 alkyl radicals.
• linear or branched C1- alkyl radicals C6 can be chosen from the group consisting of methyl, ethyl, propyl, isopropyl, isobutyl and butyl radicals.
• the linear or branched C1-C6 alkyl radicals are chosen from the group consisting of methyl, ethyl and propyl radicals. More preferably, the linear or branched C1-C6 alkyl radicals are chosen from the group consisting of methyl and ethyl radicals.
• the atoms of the aromatic rings of the amine hardener can be carbon atoms, and optionally comprise nitrogen atoms.
• all of the atoms in the aromatic rings of the amine hardener are carbon atoms.
• the aromatic rings with six atoms of the amine hardener are preferably aromatic rings with six carbon atoms.
• the radicals Ri can be identical or different.
• the amino hardener corresponds to the formula ( ⁇ ):
• amino hardener corresponds to formula (II):
• amino hardener corresponds to formula (III):
• n an integer ranging from 0 to 4, preferably from 1 to 3,
• RI and R2 identical or different, are chosen from the group consisting of a hydrogen atom and a methyl, ethyl, isobutyl or benzyl group, preferably RI and R2 both represent a hydrogen atom.
• amino hardener corresponds to formula (IV):
• n 1 or 2, preferably 1,
• RI and R2 identical or different, are chosen from the group consisting of a hydrogen atom, a methyl, ethyl, isobutyl or benzyl group, preferably RI and R2 both represent a hydrogen atom.
• the amine hardener corresponds to formula (V):
• the amino hardener is chosen from the group consisting of the compounds below and the mixtures of these compounds:
• Examples of commercially available amino hardeners which can be used in the context of the present invention include, for example, "Ethacure 100" or “Ethacure 300" from the company Albemarle, “Lonzacure DETDA” , the “Lonzacure MDEA” or the “Lonzacure MCDEA” from the company Lonza.
• the amount of amine hardener is between 1 and 15 phr. Below the indicated minimum, the targeted technical effect has been found to be insufficient, while beyond the indicated maximum, there is a risk of penalizing the raw use of the compositions.
• the level of amino hardener is within a range ranging from 5 to 10 phr, preferably from 2 to 8 phr.
• composition according to the invention comprises an imidazole of general formula (A)
• R a represents a hydrogen atom or a hydrocarbon group, optionally interrupted by one or more heteroatoms and / or substituted,
• R b represents a hydrocarbon group
• R c and R d represent, independently of one another, a hydrogen atom or a hydrocarbon group, optionally interrupted by one or more heteroatoms and / or substituted,
• R c and R d form, together with the carbon atoms of the imidazole ring to which they are attached, a ring possibly interrupted by one or more heteroatoms and / or substituted.
• the groups R a , R c and R d can, independently and when they represent a hydrocarbon group, be interrupted by a heteroatom (c In other words, a heteroatom is inserted in the hydrocarbon chain), preferably chosen from nitrogen, oxygen and sulfur, and / or substituted by a functional group.
• functional group is meant a group comprising a heteroatom, preferably chosen from amino, alkylamine, alkoxyl and hydroxyl groups, preferably chosen from hydroxyl and amino groups.
• amino group is meant a group of formula - NH 2 .
• hydroxyl group is meant a group of formula — OH.
• the imidazole of general formula (A) has groups such as:
• a hydrogen atom is chosen from the group consisting of a hydrogen atom, alkyl groups having from 1 to 20 carbon atoms, cycloalkyls having from 5 to 24 carbon atoms, aryls having from 6 to 30 carbon atoms, aralkyls having from 7 to 25 carbon atoms, optionally substituted,
• R b is chosen from the group consisting of alkyl groups having from 1 to 20 carbon atoms, cycloalkyls having from 5 to 24 carbon atoms, aryls having from 6 to 30 carbon atoms or aralkyls having from 7 to 25 carbon atoms ,
• R c and R d are independently chosen from the group consisting of a hydrogen atom, alkyl groups having from 1 to 20 carbon atoms, cycloalkyls having from 5 to 24 carbon atoms, aryls having from 6 to 30 carbon atoms or aralkyls having 7 to 25 carbon atoms; optionally substituted, or alternatively R c and R d form together with the carbon atoms of the imidazole ring to which they are attached, a ring chosen from aromatic, heteroaromatic or aliphatic rings, comprising from 5 to 12 carbon atoms, preferably 5 or 6 carbon atoms.
• R a is chosen from the group consisting of alkyl groups having from 2 to 12 carbon atoms and aralkyl groups having from 7 to 13 carbon atoms, optionally substituted. More preferably, R a is chosen from the group consisting of aralkyl groups having from 7 to 13 carbon atoms, optionally substituted and R b is chosen from the group consisting of alkyl groups having from 1 to 12 carbon atoms. Even more preferably, R a is chosen from the group consisting of aralkyl groups having from 7 to 11 carbon atoms optionally substituted and R b is chosen from the group consisting of alkyl groups having from 1 to 4 carbon atoms.
• R c and R d are independently chosen from the group consisting of a hydrogen atom and alkyl groups having from 1 to 12 carbon atoms, cycloalkyls having from 5 to 8 carbon atoms, aryls having from 6 to 24 carbon atoms and aralkyls having from 7 to 13 carbon atoms.
• R c and R d form with the carbon atoms of the imidazole ring to which they are attached, a phenyl, cyclohexene, or cyclopentene ring.
• R c and R d represent the hydrogen atom, R a and R b being chosen as described above.
• R a is a naphthylalkyl group comprising from 11 to 13 carbon atoms, optionally substituted with at least one hydroxyl group
• R b is an alkyl group having from 1 to 4 carbon atoms
• R c and R d are independently selected from the group consisting of a hydrogen atom and alkyl groups having from 1 to 12 carbon atoms.
• naphthylakyle group is meant a group of general formula (A1), where n represents an integer between 1 and 3:
• R a is a naphthylalkyl group comprising from 11 to 13 carbon atoms substituted by at least one hydroxyl group
• R b is an alkyl group having from 1 to 3 carbon atoms
• R c and R d are a hydrogen atom
• R a is a 2-naphthol-1-methyl group
• R b is a methyl group
• R c and R d are the hydrogen atom
• the compound (A) then corresponding to the formula (A2 ):
• the rubber composition according to the invention preferably comprises from 0.1 to 5 phr of imidazole of general formula (A), preferably from 0.1 to 3 phr, very preferably from 0.2 to 3 phr and very preferably 0.2 to 2 phr imidazole general formula (A).
• imidazole of general formula (A) could enter into competition with the amino hardener and modify the network obtained during crosslinking. .
• imidazoles useful for the needs of the invention are either commercially available or easily prepared by those skilled in the art according to well known techniques as described for example in documents JP2012211122, JP2007269658 or also in Science ofS j nthesis 2002, 12, 325-528.
• imidazoles useful for the needs of the invention mention may be made of 1,2-dimethylimidazole, l-decyl-2-methylimidazole, 1-benzyl-2-methylimidazole or 1 - ((2-Methyl-1H-Imidazol-1-yl) Methyl) Naphthalen-2-ol commercially available under the name "Aradur 3123" from the company Hunstman.
• composition of the tire according to the invention preferably comprises a reinforcing filler.
• the reinforcing filler may comprise any type of reinforcing filler known for its capacity to reinforce a rubber composition which can be used for the manufacture of tires, for example an organic filler such as carbon black, an inorganic reinforcing filler such as silica, or a mixture of carbon black and reinforcing inorganic filler. More preferably, the reinforcing filler mainly, or even exclusively, comprises carbon black, in particular in the case where the composition is used in an internal layer.
• the reinforcing filler may also mainly comprise an inorganic reinforcing filler, in particular in the case where the composition is used in a tread.
• Such a reinforcing filler typically consists of particles whose average size (by mass) is less than a micrometer, generally less than 500 nm, most often between 20 and 200 nm, in particular and more preferably between 20 and 150 nm.
• carbon blacks all carbon blacks are suitable, in particular blacks of the HAF, ISAF, SAF type conventionally used in tires (so-called pneumatic grade blacks).
• carbon blacks reinforcing series 100, 200 or 300 such as, for example, blacks NI 15, N134, N234, N326, N330, N339, N347, N375, or, depending on the intended 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 applications WO 97/36724 or WO 99/16600).
• Fa specific surface BET of carbon blacks is measured according to standard D6556-10 [multipoint method (at least 5 points) - gas: nitrogen - relative pressure range R / R0: 0.1 to 0.3]
• any inorganic or mineral filler (whatever its color and its natural or synthetic origin), also called “white” filler, “clear” filler even “non-black filler” as opposed to carbon black, capable of reinforcing on its own, without other means than an intermediate coupling agent, a rubber composition intended for the manufacture of tires, in particular other terms capable of replacing, in its reinforcing function, a conventional carbon black of pneumatic grade; such a charge is generally characterized, in a known manner, by the presence of hydroxyl groups (—OH) on its surface.
• —OH hydroxyl groups
• mineral fillers of the siliceous type in particular silica (Si0 2 ), or of the aluminous type, in particular of alumina (A1 2 0 3 ) are suitable.
• the silica used can be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenic silica having a BET surface as well as a CT AB specific surface, both less than 450 m 2 / g, preferably from 30 to 400 m 2 / g.
• HDS highly dispersible precipitated silicas
• mineral fillers of the aluminous type in particular alumina (A1 2 0 3 ) or aluminum (oxide) hydroxides, or also reinforcing titanium oxides, for example described in US 6,610,261 and US 6,747,087.
• reinforcing inorganic filler is also understood to mean mixtures of various reinforcing inorganic fillers, in particular highly dispersible siliceous and / or aluminous fillers.
• a reinforcing charge of another nature, in particular organic could be used, as soon as this reinforcing charge is covered with a inorganic layer such as silica, or else would have on its surface functional sites, in particular hydroxyls, making it possible to establish the bond between the filler and the elastomer in the presence or not of a covering or coupling agent.
• an at least bifunctional coupling agent intended to ensure a sufficient connection, of chemical and / or physical nature, between the filler inorganic (surface of its particles) and the diene elastomer.
• organosilanes or polyorganosiloxanes which are at least bifunctional are used.
• bifunctional is meant a compound having a first functional group capable of interacting with the inorganic charge and a second functional group capable of interacting with the diene elastomer.
• such a bifunctional compound may include a first functional group comprising a silicon atom, said first functional group being capable of interacting with the hydroxyl groups of an inorganic charge and a second functional group comprising a sulfur atom, said second functional group being capable of interacting with diene elastomer.
• the organosilanes are chosen from the group consisting of polysulphurized organosilanes (symmetrical or asymmetrical) such as bis (3-triethoxysilylpropyl) tetrasulphide, in short TESPT marketed under the name "Si69” by the company Evonik or bis disulphide - (triethoxysilylpropyle), in short TESPD marketed under the name “Si75” by the company Evonik, polyorganosiloxanes, mercaptosilanes, blocked mercaptosilanes, such as S- (3- (triethoxysilyl) propyl) octanethioate marketed by the company Momentary under the name "NXT Silane”. More preferably, the organosilane is a polysulfurized organosilane.
• the content of coupling agent is preferably less than 12 phr, it being understood that it is generally desirable to use as little as possible.
• the level of coupling agent represents from 0.5% to 15% by weight relative to the amount of inorganic filler. Its rate is preferably included in a range from 0.5 to 12 phr, more preferably included in a range ranging from 4 to 8 phr. This level is easily adjusted by a person skilled in the art according to the level of inorganic filler used in the composition.
• the rate of reinforcing filler preferably the reinforcing filler comprising predominantly or even exclusively carbon black
• the rate of reinforcing filler can be included in a range ranging from 20 to 200 phr, preferably from 30 at 150 phr, preferably from 40 to 100 phr, preferably from 50 to 80 phr.
• the crosslinking system can be any type of system known to those skilled in the art in the field of rubber compositions for tires. It can in particular be based on sulfur, and / or peroxide and / or bismaleimides.
• the crosslinking system is based on sulfur, this is called a vulcanization system.
• Sulfur can be provided in any form, in particular as molecular sulfur, or a sulfur donor.
• At least one vulcanization accelerator is also preferably present, and, optionally, also preferentially, various known vulcanization activators can be used such as zinc oxide, stearic acid or equivalent compound such as stearic acid salts and salts. of transition metals, guanidine derivatives (in particular diphenylguanidine), or also known vulcanization retardants.
• Sulfur is used at a preferential rate of between 0.5 and 12 phr, in particular between 1 and 10 phr.
• the vulcanization accelerator is used at a preferential rate of between 0.5 and 10 phr, more preferably of between 0.5 and 8.0 phr.
• accelerators of the thiazole type and their derivatives accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate type can be used as accelerator.
• MBTS 2-mercaptobenzothiazyl disulfide
• CBS N-cyclohexyl-2-benzothiazyl sulfenamide
• DCBS N-dicyclohexyl- 2-benzothiazyle sulfenamide
• TBBS N-ter-butyl-2-benzothiazyle sulfenamide
• TZTD tetrabenzylthiuram disulfide
• ZBEC zinc dibenzyldithiocarbamate
• the rubber compositions in accordance with the invention may also contain all or part of the usual additives and processing agents known to those skilled in the art and usually used in rubber compositions for tires, such as for example plasticizers. (such as plasticizing oils and / or plasticizing resins), pigments, protective agents such as anti-ozone waxes, chemical anti-ozonants, anti-oxidants, anti-fatigue agents.
• plasticizers such as plasticizing oils and / or plasticizing resins
• pigments such as plasticizing oils and / or plasticizing resins
• protective agents such as anti-ozone waxes, chemical anti-ozonants, anti-oxidants, anti-fatigue agents.
• the composition can be either in the cm state (before crosslinking or vulcanization), or in the baked state (after crosslinking or vulcanization). Gni or semi-üni and pneumatic rubber article
• the present invention also relates to a finished or semi-finished rubber article comprising a composition according to the invention.
• the present invention also relates to a tire which comprises a composition according to the invention.
• An external sidewall is an elastomeric layer placed outside the carcass reinforcement relative to the internal cavity of the tire, between the crown and the bead so as to completely or partially cover the area of the carcass reinforcement extending from the top to the bead.
• the radially inner zone and in contact with the inflation gas this zone generally being constituted by the layer which is impermeable to the inflation gases, sometimes called the inner sealing layer or inner rubber.
• the internal zone of the tire that is to say that between the external and internal zones.
• This zone includes layers or plies which are called here internal layers of the tire. These are for example carcass plies, tread underlays, plies of tire belts or any other layer which is not in contact with the ambient air or the inflation gas of the tire.
• composition defined in the present description is particularly well suited to the inner and outer layers of tires, and in particular, for the outer layers, to tread compositions.
• the internal layer can be chosen from the group consisting of carcass plies, crown plies, rod stuffing, crown feet, decoupling layers, border erasers, stuffing erasers, underlay -tread layer and combinations of these internal layers.
• the internal layer is chosen from the group consisting of carcass plies, crown plies, rod stuffing, crown feet, decoupling layers and combinations of these internal layers.
• the invention relates particularly to tires intended to equip motor vehicles of the tourism type, SUV ("Sport Utility Vehicles"), or two wheels (in particular motorcycles), or airplanes, or industrial vehicles chosen from vans, "Weight- heavy ”- ie metro, bus, road transport equipment (trucks, tractors, trailers), off-road vehicles such as agricultural or civil engineering equipment, and others.
• SUV Sport Utility Vehicles
• two wheels in particular motorcycles
• airplanes or industrial vehicles chosen from vans, "Weight- heavy ”- ie metro, bus, road transport equipment (trucks, tractors, trailers), off-road vehicles such as agricultural or civil engineering equipment, and others.
• the invention relates to articles comprising a rubber composition according to the invention, both in the cm state (that is to say, before baking) and in the baked state (that is, after crosslinking or vulcanization). ).
• the rubber composition according to the invention can be manufactured in suitable mixers, using two successive preparation phases well known to those skilled in the art:
• thermomechanical working phase or kneading which can be carried out in a single thermomechanical step during which one introduces, into a suitable mixer such as a usual internal mixer (for example of the type 'Banbury'), all the necessary constituents, in particular the elastomeric matrix, the fillers, any other miscellaneous additives, with the exception of the crosslinking system.
• a suitable mixer such as a usual internal mixer (for example of the type 'Banbury')
• the incorporation of the filler into the elastomer can be carried out in one or more times by thermomechanically kneading.
• the filler is already incorporated in whole or in part in the elastomer in the form of a masterbatch (“masterbatch” in English) as described for example in applications WO 97/36724 or WO 99 / 16600, it is the masterbatch which is directly kneaded and where appropriate the other elastomers or fillers present in the composition which are not in the form of masterbatch are incorporated, as well as any other miscellaneous additives other than the crosslinking system.
• masterbatch in English
• the non-productive phase is carried out at high temperature, up to a maximum temperature between 110 ° C and 190 ° C, preferably between 130 ° C and 180 ° C, for a period generally between 2 and 10 minutes.
• a second mechanical working phase (so-called "productive" phase), which is carried out in an external mixer such as a cylinder mixer, after cooling of the mixture obtained during the first non-productive phase to a lower temperature , typically less than 110 ° C, for example between 40 ° C and 100 ° C.
• the crosslinking system is then incorporated, and the whole is then mixed for a few minutes, for example between 2 and 15 min.
• compositions comprising for example the following steps:
• between 1 and 15 phr of an amino hardener and an imidazole of general formula (A) can be introduced, independently of each other, either during the non-productive phase (a), either during the productive phase (c).
• the epoxy resin is introduced during the non-productive phase (a) while the amine hardener and the imidazole of general formula (A) are introduced during the productive phase (c).
• the final composition thus obtained can then be calendered, for example in the form of a sheet, a plate in particular for characterization in the laboratory, or else extruded in the form of a semi-finished (or profiled) rubber used for the manufacture of a tire.
• the crosslinking of the composition can be carried out in a manner known to those skilled in the art, for example at a temperature between 130 ° C. and 200 ° C., under pressure.
• the invention relates to at least one of the objects described in the following points:
• a rubber composition based on at least:
• an amino hardener comprising at least two primary amine functions, located on at least one six-atom aromatic ring, said at least one six-atom aromatic ring comprising:
• radicals Ri identical or different, chosen from the group consisting of linear or branched C1-C6 alkyl radicals, halogens, ethers, tertiary amines, thioethers, ketones, esters and amides, substituted by linear or branched C1-C6 alkyl radicals, such that the at least one six-atom aromatic ring does not contain a hydrogen atom located in the ortho position with respect to the primary amine functions,
• R a represents a hydrogen atom or a hydrocarbon group, optionally interrupted by one or more heteroatoms and / or substituted,
• R b represents a hydrocarbon group
• R c and R d independently of one another represent a hydrogen atom or a hydrocarbon group, optionally interrupted by one or more heteroatoms and / or substituted, • or else R c and R d form together with the carbon atoms of the imidazole ring to which they are attached, a ring possibly interrupted by one or more heteroatoms and / or substituted.
• aromatic epoxy resins are chosen from the group consisting of 2,2 bis [4- (glycidyloxy) phenyl] propane, poly [(o-cresylglycidyl ether) -co- formaldehyde], poly [(phenylglycidyl ether) -co-formaldehyde], poly [(phenylglycidyl ether) - co (hydroxybenzaldehyde glycidyl ether)], epoxy amine aromatic resins and mixtures of these compounds.
• a rubber composition according to any one of the preceding points in which the linear or branched C1-C6 alkyl radicals are chosen from the group consisting of methyl, ethyl, propyl, isopropyl, isobutyl and butyl radicals, preferably in the group consisting of methyl, ethyl and propyl radicals.
• a rubber composition according to any one of the preceding points in which the at least one six-atom aromatic ring is a six-carbon aromatic ring.
• n an integer ranging from 0 to 4, preferably from 1 to 3,
• RI and R2 identical or different, are chosen from the group consisting of a hydrogen atom and a methyl, ethyl, isobutyl or benzyl group, preferably RI and R2 both represent a hydrogen atom.
• n 1 or 2, preferably 1,
• RI and R2 identical or different, are chosen from the group consisting of a hydrogen atom, a methyl, ethyl, isobutyl or benzyl group, preferably RI and R2 both represent a hydrogen atom.
• a rubber composition according to any one of the preceding points in which the content of amine hardener is within a range ranging from 5 to 10 phr, preferably from 2 to 8 phr. 19. A rubber composition according to any one of the preceding points, in which, in the imidazole of general formula (A):
• - is chosen from the group consisting of a hydrogen atom, alkyl groups having from 1 to 20 carbon atoms, cycloalkyls having from 5 to 24 carbon atoms, aryls having from 6 to 30 carbon atoms, aralkyls having from 7 with 25 carbon atoms, optionally substituted,
• - 3 ⁇ 4 is chosen from the group consisting of alkyl groups having from 1 to 20 carbon atoms, cycloalkyls having from 5 to 24 carbon atoms, aryls having from 6 to 30 carbon atoms or aralkyls having from 7 to 25 carbon atoms ,
• R c and R d are independently chosen from the group consisting of a hydrogen atom, alkyl groups having from 1 to 20 carbon atoms, cycloalkyls having from 5 to 24 carbon atoms, aryls having from 6 to 30 atoms carbon or aralkyls having 7 to 25 carbon atoms, optionally substituted, or alternatively R c and R d form, together with the carbon atoms of the imidazole ring to which they are attached, a ring chosen from aromatic, heteroaromatic or aliphatic rings, comprising from 5 to 12 carbon atoms, preferably 5 or 6 carbon atoms.
• R a is chosen from the group consisting of alkyl groups having from 2 to 12 carbon atoms and aralkyls having from 7 to 13 carbon atoms, optionally substituted.
• R a is chosen from the group consisting of aralkyl groups having from 7 to 13 carbon atoms optionally substituted and R b is selected from the group consisting of alkyl groups having from 1 to 12 carbon atoms.
• R a is chosen from the group consisting of aralkyl groups having from 7 to 11 carbon atoms optionally substituted and R b is selected from the group consisting of alkyl groups having from 1 to 4 carbon atoms.
• R c and R d are independently chosen from the group consisting of a hydrogen atom and the groups alkyls having 1 to 12 carbon atoms, cycloalkyls having 5 to 8 carbon atoms, aryls having from 6 to 24 carbon atoms and aralkyls having from 7 to 13 carbon atoms, R c and R d being very preferably the hydrogen atom.
• R a is a naphthylalkyl group comprising from 11 to 13 carbon atoms substituted by at least one hydroxyl group
• R b is an alkyl group having from 1 to 3 carbon atoms
• R c and R d are a hydrogen atom
• R a is a 2-naphtholmethyl group
• R b is a methyl group
• R c and R d are the hydrogen atom
• a rubber composition according to any one of the preceding points in which the level of imidazole of general formula (A) is within a range ranging from 0.1 to 5 phr.
• a finished or semi-finished rubber article comprising a rubber composition according to any one of the preceding points.
• a tire comprising a rubber composition according to any one of points 1 to 27.
• a tire according to point 30 in which the inner layer is chosen from the group consisting of carcass plies, crown plies, bead-stuffing, crown feet, decoupling layers, border erasers, erasers padding, the tread underlayment and combinations of these inner layers.
• results are expressed in base 100, the value 100 being assigned to the control.
• a result greater than 100 indicates that the composition of the example considered has greater rigidity.
• an elastomer is introduced into an internal mixer (final filling rate: approximately 70% by volume), the initial tank temperature of which is approximately 60 ° C. diene, the reinforcing filler, between 1 and 30 phr of the epoxy resin, as well as the various other ingredients with the exception of the vulcanization system, the amine hardener and the imidazole.
• Thermomechanical work (non-productive phase) is then carried out in one step, which lasts a total of approximately 3 to 4 min, until a maximum "fall" temperature of 165 ° C is reached.
• the mixture thus obtained is recovered, it is cooled and then sulfur, a sulfenamide type accelerator, the amine hardener and the imidazole are incorporated on a mixer (homo-finisher) at 30 ° C., mixing the whole (productive phase) for an appropriate time (for example between 5 and 12 min).
• compositions thus obtained are then calendered either in the form of plates (thickness of 2 to 3 mm) or of thin sheets of rubber for measuring their physical or mechanical properties, or extruded in the form of a profile.
• the crosslinking of the composition is carried out at a temperature of 150 ° C, for 60 min, under pressure.
• Example 1
• Compositions C.2 and C.3 contain an epoxy resin and a polyamine hardener to replace the formo-phenolic resin / HMT hardener (s) couple contained in the conventional control composition C.L
• compositions presented in table 1 do not cause the formation of formaldehyde during cooking.
• the conforming composition has a rigidity at room temperature similar to compositions Cl and C.2, and has a rigidity at high temperature greater than the composition without imidazole C.2, similar to composition Cl, with the advantage over the latter of not forming formaldehyde during cooking.
• Test C.5 shows that just increasing the amount of hardener increases stiffness at low temperatures but not stiffness at high temperatures.
• Test C.13 shows that imidazole used without a hardener does not improve rigidity at high temperatures. It is therefore the combination of the hardener and the imidazole which makes it possible to obtain both satisfactory rigidity at room temperature and at high temperature.

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• 2018
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