EP2934909A1 - Composition de caoutchouc comportant de la cellulose - Google Patents
Composition de caoutchouc comportant de la celluloseInfo
- Publication number
- EP2934909A1 EP2934909A1 EP13814899.4A EP13814899A EP2934909A1 EP 2934909 A1 EP2934909 A1 EP 2934909A1 EP 13814899 A EP13814899 A EP 13814899A EP 2934909 A1 EP2934909 A1 EP 2934909A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- cellulose
- group
- coupling agent
- composition according
- grafting
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- 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
- C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
- C08L9/06—Copolymers with styrene
Definitions
- the present invention relates to diene rubber compositions reinforced with an organic filler for the manufacture of tires or semi-finished products for tires, in particular to the treads of these tires.
- the cellulose in the native state is in the form of very elongated microfibrils of nanometric diameter, often organized into fibers. This cellulose can be found in higher plants, but also in certain algae, certain fungi, bacteria, amoebae and even certain marine animals.
- micro-fibrils means these extremely long and fine elements consisting of macromolecular cellulose chains aligned in the fiber direction extracted from the native structure.
- the micro-fibrils are in the form of highly elongated filaments of indefinite length and consisting of an alternation of crystalline zones and amorphous zones.
- cellulose nanocrystals or “whiskers” is understood to mean anisotropic crystals of finite length and of nanometric diameter obtained by hydrolysis of the amorphous parts of microfibrils and consisting of fiber-oriented macromolecular cellulose chains.
- these cellulose particles have an unfortunate tendency in the elastomeric matrix to agglomerate with each other.
- JP2009191198 discloses a rubber composition comprising cellulose nano fibers obtained by liquid mixing in an aqueous medium of the elastomer and cellulose fibers in the presence of a silane coupling agent to improve the adhesion of the fibers. and elastomer.
- EP 2072 574 describes the use of chemically modified cellulose microfibrils by an acetylation reaction, alkyl esterification, complex esterification, keto-esterification, alkyl carbamation or aryl carbamation, as as a reinforcing filler in a rubber composition.
- the processes for implementing and modifying cellulose are limited by the polar and hydrophilic nature of its surface, which leads to obtaining strong interactions between the surfaces of the substrate, and with polar and protic solvents.
- the dry form obtained is aggregated and has a small specific surface area limiting its reinforcing nature.
- the alternative generally used is to make a premix or masterbatch of the filler and the matrix in suspension, for example using a latex in water.
- the chemical modification of the cellulose in the aqueous medium is limited because of the low reactivity of the substrate and the highly protic nature of the water. It is then possible to use organic solvents to allow this modification.
- cellulose has a strong tendency to aggregate more or less irreversibly depending on the polarity of the solvent used. Moreover, these environments pose problems of toxicity and are not respectful of the environment.
- the subject of the invention is the use of cellulose as reinforcing filler of a rubber composition, that is to say capable of reinforcing on its own, without any other means than an intermediate coupling agent, a diene rubber composition. intended for the manufacture of tires, in other words able to replace, in its reinforcing function, a conventional load of carbon black or silica pneumatic grade.
- the Applicant has surprisingly discovered that the cellulose formed of microfibrils, chemically modified by grafting on said cellulose coupling agent molecules, could play this role of reinforcing filler, and in particular the cellulose in the form of an airgel or finely divided cellulose powder.
- airgel means a gel-like material in which the liquid component is replaced by gas. It is a solid with very low density with several remarkable properties, including a very large accessible surface with a significant value of the ratio between the surface and the mass.
- cellulose powder is understood to mean a solid divided into fine particles, these particles being made of cellulose, or even airgel of cellulose, and having a significant value of the ratio between the surface and the mass. .
- the subject of the invention is therefore a rubber composition based on at least one diene elastomer and at least one reinforcing filler, this reinforcing filler comprising cellulose grafted with coupling agent molecules capable of binding it to Diene elastomer, these molecules comprising at least one function A and one function B such that:
- A represents a functional group ("A" function) capable of binding chemically to cellulose, and which comprises at least one heteroatom chosen from oxygen, phosphorus, halogens, nitrogen and sulfur,
- - B represents a functional group (function "B") capable of binding physically and / or chemically to the diene elastomer;
- A is chosen from acyl chlorides, anhydrides, carboxylic acids, isocyanates, organic or inorganic esters, alkyl chlorides and epoxides.
- B carries mono or polysulfide functions.
- the coupling agent corresponds to formula (I): AXB, in which the group X represents a divalent linking group comprising from 1 to 18 carbon atoms, preferably a C 1 -C 18 alkylene group or a group arylene in
- the coupling agent corresponds to formula (II):
- the coupling agent corresponds to formula (III): AXBXA, in which the group X represents a divalent linking group comprising from 1 to 18 carbon atoms, preferably a group C1-C18 alkylene or a C6-C12 arylene group, preferably B is Sp where p is a number greater than or equal to 2, preferably 2 to 8 (preferably 2 to 5).
- the invention also relates to a tire comprising a composition as described above.
- the subject of the invention is also a cellulose formed of micro fibrils, chemically modified by grafting onto said cellulose coupling agent molecules capable of binding it to a diene elastomer, these molecules comprising at least one function A and one function B such as than :
- A represents a functional group ("A" function) capable of binding chemically to cellulose, and which comprises at least one heteroatom chosen from oxygen, phosphorus, halogens, nitrogen and sulfur,
- - B represents a functional group (function "B") capable of binding physically and / or chemically to the diene elastomer;
- the functions A and B being connected by an at least divalent group X; said cellulose being in the form of an airgel or a cellulose powder.
- the invention finally relates to a process for obtaining an airgel or a cellulose powder as described above.
- the measurement of a degree of functionalization of the load can be performed from gravimetric measurements. This quantity then makes it possible to quantify within the modified filler, the graft fraction and the rigid phase fraction.
- a quantity of cellulose airgel between 1 and 10 g is stored in a beaker of 50 to 500 ml previously tared on a Mettler AE 163 scale providing a measurement with an accuracy of 4 * 10 -4 g.
- the substrate is dried for at least 6 h at 60 ° C. in a Jouan oven.
- the dry substrate is weighed on a Mettler AE 163 providing a measure with an accuracy of 4 * 10 "4 g (m this ii i).
- the product is stored in a beaker of 50 to 500 ml previously calibrated on a Mettler AE 163 scale providing a measurement with an accuracy of 4 * 10 "4 g.
- the product is dried for at least 6 hours at 60 ° C. in a Jouan oven.
- the dry product was weighed on a Mettler AE 163 providing a measure with an accuracy of 4 * 10 "4 g (m this ii F).
- % graft (m ce ii F - m ce in) / m ce in * 100 b) Spectroscopic measurements to confirm the presence of a graft
- the control of the chemical modification can be reinforced by the use of spectroscopic techniques sensitive to the chemical environment, in our case IR and solid NMR.
- spectroscopic techniques sensitive to the chemical environment, in our case IR and solid NMR.
- the graft is an acyl chloride
- it is observed by Infra-Red the appearance of a vibration band of the carbonyl function at about 1750 cm -1 distinct from that of the acyl chloride ( reagent, 1800 cm -1 ), and carboxylic acid (hydrolyzed reactant, 1700 cm -1 )
- the carbon of carbonyl function appears to be about 175
- This signal is present in the ester (product), but also in the reagent which also has a specific band at 45 ppm, which makes it possible to differentiate them.It is also present in the acid (hydrolysed reagent) but has was then identified at around 180
- FTIR Fourier Transform IR
- the analyzes are carried out on a Brucker Avance 400 MHz spectrometer, by magic angle rotation (MAS) at 12000Hz, accumulating about 2000 acquisitions.
- MAS magic angle rotation
- a specific surface area, Ssp in m 2 / cc, can be converted to a lateral dimension of an equivalent square-section square fiber a in nm, using the following relationship:
- n a / 0.57
- DSg can then be converted into bond density by the formula:
- Bond density 5 * DSg / DS max area
- the protocol can be followed identically in the case of a cellulose powder.
- the BET surface area is determined in a known manner 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 (multipoint volumetric method (5 points) - gas: nitrogen - with a modification compared to the standard by applying a degassing for 5 hours at 50 ° C - relative pressure range p / po: 0.05 to 0.17)
- the present invention relates to a rubber composition based on at least one diene elastomer and at least one reinforcing filler, said reinforcing filler comprising cellulose grafted with coupling agent molecules capable of binding to the diene elastomer, these molecules comprising at least one function A and one function B such that:
- A represents a functional group ("A" function) capable of binding chemically to cellulose, and which comprises at least one heteroatom chosen from oxygen, phosphorus, halogens, nitrogen and sulfur,
- - B represents a functional group (function "B") capable of binding physically and / or chemically to the diene elastomer;
- this grafted cellulose is in the form of an airgel or a cellulose powder.
- the present invention also relates to cellulose formed of micro fibrils, chemically modified by grafting on said cellulose coupling agent molecules capable of binding to a diene elastomer, these molecules comprising at least one function A and one function B such that :
- A represents a functional group ("A" function) capable of binding chemically to cellulose, and which comprises at least one heteroatom chosen from oxygen, phosphorus, halogens, nitrogen and sulfur,
- - B represents a functional group (function "B") capable of binding physically and / or chemically to the diene elastomer;
- the functions A and B being connected by an at least divalent group X; said cellulose being in the form of an airgel or a powder of celllulose.
- composition-based is meant a composition comprising the mixture and / or the reaction product of the various constituents used, some of these basic constituents being capable of or intended to react with one another, less in part, during the various phases of manufacture of the composition, in particular during its crosslinking or vulcanization.
- 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).
- Cellulose is an organic polymer of formula It is a linear homopolymer composed of numerous D-Anhydroglucopyranose (AGU) units linked together by ⁇ - (1 ⁇ 4) glyco diket linkages. These linear chains are maintained in extended conformation by intramolecular bonds and associate with each other by intermolecular side bonds of the hydrogen bonding type, which gives the cellulose its fibrous and rigid structure.
- AGU D-Anhydroglucopyranose
- the cellulose microfibrils are derived from biosynthetic processes and are in the form of objects of nanometric diameter (typically 4 to 1000 nm in diameter) and of indefinite length well above one micron. They consist of a succession of zones with long macromolecular chains aligned in the fiber direction (nanocrystals) and short disordered amorphous zones (defects).
- micro-fibrils or micro-fibrillation
- the individualization of the micro-fibrils can be obtained by known methods of high-pressure mechanical homogenization, as described by way of example in the document USP 4,483,743, AF Turbak, "Microfibrillated cellulose", 1984, USA, or enzymatic or chemical or a combination of several of these techniques on cellulosic substrates such as paper pulps, agricultural waste, by-products of the food industry or any other cellulosic source terrestrial or marine, d animal, plant or microbial origin. All these processes have in common the obtaining of a suspension of microfibrils of diameter
- the fiber dispersion is treated in a high pressure homogenizer (such as, for example, high pressure homogenizers marketed by the company APV Manton).
- the product obtained is a dispersion in water having mass concentrations of the order of 1 to 2%.
- the drying step is then carried out by any method preserving the accessibility of the cellulose surfaces and therefore the formation of airgel or powders having a much larger surface area than a simple evaporative drying and a much less dense structure.
- cryoprotectant additive rapid freezing, atomization (or spray-drying), supercritical CO 2, fluidized bed drying or lyophilization from a solvent can thus be mentioned in a non-limiting manner. non-crystallizable.
- the suspension may be previously pre-concentrated by centrifugation, by gravity filtration or under vacuum or by osmotic pressure or by means of an evaporator / concentrator (Rotavapor).
- the colloidal dispersion formed by the cellulose microfibrils can be, for example, centrifuged and then redispersed in tertbutanol alcohol, then frozen in liquid nitrogen and then freeze-dried in order to obtain a cellulose airgel formed of micro-fibrils.
- This alcoholic solvent before the drying step by lyophilization avoids aggregation of the particles and therefore the formation of open aerogels to have a larger surface area.
- the BET specific surface area is greater than or equal to 10 mVg, and preferably greater than or equal to 50 m 2 / g.
- the airgel obtained or the cellulose powder is then subjected to modification by a graft (the reaction pattern of which follows) carried out in a heterogeneous phase on the surface of the particles and in particular in the gas phase in order to graft a coupling agent onto the microparticles. fibrils of cellulose.
- the previously obtained airgel or the powder undergoes a substitution reaction which is preferably carried out in the heterogeneous phase, in particular in the gas phase.
- the reactions for forming the covalent bond are those conventionally described in the field of cellulose chemistry and may be, without being exhaustive, carried out by esterification from acid derivatives chosen in particular from acyl chloride, anhydrides, the carboxylic acids, by carbamylation with isocyanates, by acetalization with aldehydes or by etherification from alkyl chlorides or epoxide. They can be easily carried out on a native cellulose substrate or on an oxidized substrate, or selectively in C6 (TEMPO, NO2 oxidation) or by oxidative cleavage of the C2-C3 glycol linkage (oxidation periodate).
- TEMPO TEMPO, NO2 oxidation
- the modification can be carried out by ester formation with the aid of organic or inorganic alcohol or esters, or else alkylating agents, by formation of acyl chloride by SOCL2, anhydrides with a carboxylic acid, and or by amidation with amines (carboxylic acid) or imines (aldehydes).
- the reaction is carried out by placing in a reactor, the airgel or the powder, formed of cellulose microfibrils and the reagent at a temperature and pressure that are stable so as to vaporize the reagent, and introducing a controlled flow of nitrogen through the reactor inlet; the reaction products (leaving groups and / or reagent residues) being discharged through the outlet connected to a vacuum pump.
- the reagent can also be vaporized separately and introduced into the reactor chamber.
- heterogeneous phase grafting are possible, in particular in the case of a cellulose powder, grafting in a fluidized bed by a stream of vaporized reagent.
- the degree of grafting of the cellulose is preferably greater than 0.1 bonds per nm 2 measured by gravimetry and relative to the BET surface, it varies more preferably from 1 to 20 bonds per nm 2 and even more preferably from 3 to 12 bonds. by nm 2 , and even more preferably from 3 to 6 bonds per nm 2 .
- the coupling agent is in the form of molecules comprising at least one function A and one function B such that:
- A represents a functional group ("A" function) capable of binding chemically to cellulose, and which comprises at least one heteroatom chosen from oxygen, phosphorus, halogens, nitrogen and sulfur,
- - B represents a functional group (function "B") capable of binding physically and / or chemically to the diene elastomer;
- A is preferably chosen from acyl chlorides, anhydrides, carboxylic acids, isocyanates, alkyl chlorides, organic or inorganic esters, aldehydes, epoxides or amines, primary or secondary.
- B carries mono or polysulfide functions.
- the coupling agent may correspond to formula (I): AXB, in which X represents a divalent linking group comprising from 1 to 18 carbon atoms, and preferably a C 1 -C 18 alkylene group or a C 5 arylene group. 6 -C 12, more particularly a C 1 -C 10 alkylene group, especially a C 1 -C 4 alkylene group.
- the coupling agent corresponds to formula (II):
- A-X-B wherein X is a trivalent group such as tri-substituted cycloalkyl, especially tri-substituted cyclohexane.
- B is in the form of a blocked mercapto function of formula:
- R represents hydrogen or a monovalent hydrocarbon group chosen from alkyls, linear or branched, cycloalkyls or aryls, having from 1 to 18 carbon atoms,
- n is a number greater than or equal to 1; m preferably ranges from 1 to 8, even more preferably m is equal to 1 (preferably from 2 to 5).
- B is in the form of a polysulfurized function of formula:
- R represents a monovalent hydrocarbon group chosen from alkyls, linear or branched, cycloalkyls or aryls, having from 1 to 30 carbon atoms,
- r is a number greater than or equal to 2, preferably from 2 to 8 (preferably from 2 to 5).
- the coupling agent corresponds to formula (III): ## STR2 ## in which:
- the group X represents a divalent linking group comprising from 1 to 18 carbon atoms, preferably a C 1 -C 18 alkylene group or an arylene group in
- B represents S p where p is a number greater than or equal to 2, preferably from 2 to 8 (preferably from 2 to 5).
- Particularly suitable 3,3'-dithio-dipropionic acid chloride preferably from 2 to 8 (preferably from 2 to 5).
- composition in accordance with the invention comprises at least one reinforcing filler comprising a cellulose grafted with coupling agent molecules as described in the preceding paragraphs.
- this grafted cellulose represents the majority reinforcing filler.
- it is in the form of an airgel or a chemically modified cellulose powder as described above.
- the reinforcing filler may also comprise other fillers, in particular with an organic filler and / or an inorganic filler.
- carbon blacks especially reinforcing carbon blacks of the series 100, 200 or 300 (ASTM grades), such as blacks NI 15, N134, N234, N326, N330, N339, N347 , N375, or, depending on the intended applications, blacks of higher series (for example N400, N660, N683, N772).
- any inorganic or mineral filler regardless of its color and origin (natural or synthetic), also called “white” charge, “clear” charge or “black non-black” filler as opposed to carbon black, this inorganic filler being capable of reinforcing on its own, without any other means than an intermediate coupling agent, a rubber composition intended for manufacturing a tire tread, in other words able to replace, in its reinforcing function, a conventional tire grade carbon black for tread.
- Such a filler is generally characterized by the presence of functional groups, in particular hydroxyl (-OH), at its surface, thereby requiring the use of an agent or coupling system intended to ensure a stable chemical bond between the isoprene elastomer and said charge.
- the reinforcing inorganic filler is a filler of the siliceous or aluminous type, or a mixture of these two types of filler.
- the silica (SiO 2 ) 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 area both less than 450 m 2 / g, preferably 30 to 400 m 2 / g.
- the total reinforcing filler content will be chosen between 10 and 200 phr, more preferably between 10 and 150 phr, more preferably between 20 and 110 phr.
- composition according to the invention comprises at least one diene elastomer.
- iene 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 monomeric diene 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” 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 "substantially 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%.
- iene elastomer can be understood more particularly to be used in the compositions according to the invention:
- 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, aryl-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene.
- Suitable vinylaromatic compounds are, for example, styrene, ortho-, meta-, para-methylstyrene, the commercial vinyl-toluene mixture, para-methylstyrene and the like.
- P10-2884 / SC tert-butylstyrene methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene.
- the copolymers may contain between 99% and 20% by weight of diene units and between 80% 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.
- alkoxysilane groups as described for example in FR 2,765,882 or US 5,977,238), carboxylic groups (as described for example in WO 01/92402 or US 6,815,473, WO 2004/096865 or US 2006 / 0089445) or polyether groups (as described for example in EP 1 127 909 or US 6,503,973, WO 2009/000750 and WO 2009/000752).
- Functional elastomers that may be mentioned are those prepared by the use of a functional initiator, especially those carrying an amine or tin function (see, for example, WO 2010072761).
- elastomers such as SBR, BR, NR or IR
- SBR surface potential
- BR BR
- NR IR
- elastomers such as SBR, BR, NR or IR
- Suitable polybutadienes and in particular those having a content (mol%) in units -1.2 between 4%> and 80%> or those having a content (%> molar) in cis-1,4 greater than 80%> polyisoprenes, butadiene-styrene copolymers and in particular those having a Tg (glass transition temperature (Tg, measured according to ASTM D3418) between 0 ° C. and -70 ° C. and more particularly between -10 ° C.
- Tg glass transition temperature
- styrene content of between 5% and 60% by weight and more particularly between 20% and 50%, a content (%> molar) in -1,2 bonds of the butadiene part between 4% and 75%, a content (mol%) of trans-1,4 bonds of between 10% and 80%, butadiene-isoprene copolymers and in particular those having an isoprene content of between 5% and 90%.
- the isoprene-styrene copolymers and especially those having a styrene content of between 5% and 50% by weight and a e Tg between -5 ° C and -50 ° C.
- styrene content of between 5% and 50% by weight and a e Tg between -5 ° C and -50 ° C.
- e Tg between -5 ° C and -50 ° C.
- butadiene-styrene-isoprene copolymers it is particularly suitable for those having a
- P10-2884 / SC styrene content between 5% and 50% by weight and more particularly between 10%> and 40%>, an isoprene content of between 15% and 60% by weight and more particularly between 20% and 50%, a content of in butadiene of between 5% and 50% by weight and more particularly between 20% and 40%, a content (mol%) in -1,2 units of the butadiene part of between 4% and 85%; content (mol%) in trans-1,4 units of the butadiene part of between 6% and 80%, a content (mol%) in units -1,2 plus -3,4 of the isoprene part of between 5% and 70% and a content (mol%) in trans units -1.4 of the isoprene part of between 10% and 50%), and more generally any butadiene-styrene-isoprene copolymer having a Tg of between -5 ° C. and 70 ° C.
- the diene elastomer (s) of the composition according to the invention are preferably chosen from the group of highly unsaturated diene elastomers consisting of polybutadienes (abbreviated as "BR"), synthetic polyisoprenes (IR) and natural rubber (NR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers.
- BR polybutadienes
- IR synthetic polyisoprenes
- NR natural rubber
- butadiene copolymers are more preferably selected from the group consisting of butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR) and isoprene-copolymers.
- SBIR butadiene-styrene
- the diene elastomer is predominantly (ie, for more than 50 phr) an SBR, whether it is an emulsion-prepared SBR ("ESBR") or an SBR prepared in solution (“SSBR”), or a blend (blend) SBR / BR, SBR / NR (or SBR / IR), BR NR (or BR / IR), or SBR BR NR (or SBR / BR / IR).
- an SBR elastomer In the case of an SBR elastomer (ESBR or SSBR), an SBR having an average styrene content, for example between 20% and 35% by weight, or a high styrene content, for example 35% by weight, is used in particular. at 45%, a vinyl content of the butadiene part of between 15% and 70%, a content (mol%) of trans-1,4 bonds of between 15% and 75% and a Tg of between -10 ° C. and - 55 ° C; such an SBR can be advantageously used in admixture with a BR preferably having more than 90% (mol%) of cis-1,4 bonds.
- the diene elastomer is predominantly (for more than 50 phr) an isoprene elastomer.
- the compositions of the invention are intended to constitute, in tires, the rubber matrices of certain treads (for example for industrial vehicles), crown reinforcing plies (for example work webs, protective webs or hoop webs), carcass reinforcement plies, flanks, beads, protectors, underlayments, rubber blocks and other internal gums providing the interface between aforementioned areas of the tires.
- isoprene elastomer in known manner a homopolymer or copolymer of isoprene, 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 examples include butyl rubber - IIR), isoprene-styrene (SIR), isoprene-butadiene (BIR) or isoprene-butadiene-styrene (SBIR).
- This isoprene elastomer is preferably natural rubber or synthetic cis-1,4 polyisoprene; of these synthetic polyisoprenes, polyisoprenes having a content (mol%) of cis-1,4 bonds greater than 90%, more preferably still greater than 98%, are preferably used.
- the composition according to the invention may contain less than an essentially saturated diene elastomer, in particular at least one EPDM copolymer or a butyl rubber (optionally chlorinated or brominated), that these copolymers are used alone or in admixture with highly unsaturated diene elastomers as mentioned above, in particular NR or IR, BR or SBR.
- the rubber composition comprises a blend of one (or more) diene elastomers called "high Tg” having a Tg between -70 ° C and 0 ° C and d one (or more) diene elastomers known as "low Tg” between -110 ° C and -80 ° C, more preferably between -105 ° C and -90 ° C.
- the high Tg elastomer is preferably selected from the group consisting of S-SBR, E-SBR, natural rubber, synthetic polyisoprenes (having a (mol%) content of cis-1,4 linkages of preferably greater than 95%>), BIR, SIR, SBIR, and mixtures of these elastomers.
- the low Tg elastomer preferably comprises butadiene units at a level (mol%) of at least 70%); it consists preferably of a polybutadiene (BR) having a content (mol%) of cis-1,4 chains greater than 90%.
- the rubber composition comprises, for example, from 30 to 100 phr, in particular from 50 to 100 phr, of a high Tg elastomer in a blend with 0 to 70 phr, in particular from 0 to 50 phr, of a low Tg elastomer; according to another example, it comprises for all 100 pce one or more SBR prepared (s) in solution.
- the diene elastomer of the composition according to the invention comprises a blend of a BR (as low elastomer Tg) having a rate (mol%) of cis chains -1.4 greater than 90%, with one or more S-SBR or E-SBR (as elastomer (s) high Tg).
- composition according to the invention may contain a single diene elastomer or a mixture of several diene elastomers, the diene elastomer or elastomers which may be used in combination with any type of synthetic elastomer other than diene, or even with polymers other than elastomers, for example thermoplastic polymers.
- the crosslinking system is preferably a vulcanization system, that is to say a system based on sulfur (or a sulfur-donor agent) and a primary vulcanization accelerator.
- a vulcanization system that is to say a system based on sulfur (or a sulfur-donor agent) and a primary vulcanization accelerator.
- various known secondary accelerators or vulcanization activators such as zinc oxide.
- Sulfur is used at a preferential rate of between 0.5 and 12 phr, in particular between 1 and 10 phr.
- the primary vulcanization accelerator is used at a preferred level of between 0.5 and 10 phr, more preferably between 0.5 and 5.0 phr.
- accelerator primary or secondary
- any compound capable of acting as an accelerator of vulcanization of diene elastomers in the presence of sulfur in particular thiazole-type accelerators and their derivatives, accelerators of thiuram type, zinc dithiocarbamates.
- accelerators are for example selected from the group consisting of 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS”), tetrabenzylthiuram disulfide (“TBZTD”), N-cyclohexyl-2-benzothiazyl sulfenamide (“CBS”), N, N dicyclohexyl-2-benzothiazyl sulphenamide (“DCBS”), N-tert-butyl-2-benzothiazyl sulphenamide (“TBBS”), N-tert-butyl-2-benzothiazyl sulphenimide (“TBSI”), zinc dibenzyldithiocarbamate (“ ZBEC ”) and mixtures of these compounds.
- MBTS 2-mercaptobenzothiazyl disulfide
- TBZTD tetrabenzylthiuram disulfide
- CBS N-cyclohexyl-2-benzothiazyl sulfen
- the rubber compositions in accordance with the invention may also comprise all or part of the usual additives normally used in elastomer compositions intended for the manufacture of tires, in particular treads, for example plasticizers or oils. of extension, whether these are of aromatic or non-aromatic nature, pigments, protective agents such as anti-ozone waxes, chemical antiozonants, anti-oxidants, agents
- acceptors for example phenolic novolak resin
- methylene donors for example HMT or H3M
- these compositions comprise, as preferential non-aromatic or very weakly aromatic plasticizing agent, at least one compound chosen from the group consisting of naphthenic, paraffinic, MES, TDAE, ester (especially trioleate) oils.
- glycerol the hydrocarbon plasticizing resins having a high Tg preferably greater than 30 ° C, and mixtures of such compounds.
- compositions may also contain, in addition to the coupling agents, coupling activators, reinforcing filler recovery agents or, more generally, processing aid agents that are capable in a known manner, by means of an improvement in the dispersion of the filler in the rubber matrix and a lowering of the viscosity of the compositions, to improve their ability to implement in the green state.
- processing aid agents that are capable in a known manner, by means of an improvement in the dispersion of the filler in the rubber matrix and a lowering of the viscosity of the compositions, to improve their ability to implement in the green state.
- inert fillers ie, non-reinforcing
- inert fillers such as clay particles, bentonite, talc, chalk, kaolin, used for example in flanks or treads of colored tires.
- the rubber compositions of the invention are manufactured in appropriate mixers, using two successive preparation phases according to a general procedure well known to those skilled in the art: a first phase of work or thermomechanical mixing (sometimes called phase “non-productive") at a high temperature, up to a maximum temperature of between 130 ° C and 200 ° C, preferably between 145 ° C and 185 ° C, followed by a second mechanical working phase (sometimes referred to as "Productive” phase) at lower temperature, typically below 120 ° C, for example between 60 ° C and 100 ° C, finishing phase during which is incorporated the crosslinking system or vulcanization.
- a first phase of work or thermomechanical mixing sometimes called phase "non-productive”
- a second mechanical working phase sometimes referred to as "Productive” phase
- the airgel of cellulose microfibrils A is obtained from the hardwood pulp obtained by sulphite treatment.
- the pulp is treated on a refiner (model marketed by Valley Laboratory Equipment of the Voith brand Serial No. 109-F-1627 X81734, 22L capacity) at the concentration of 2% by weight for 6 hours.
- aqueous dispersion obtained undergoes a different treatment, being centrifuged for 30 minutes at a speed of 11200 rpm at 25 ° C.
- the cake thus obtained is redispersed in pure terbutanol to a concentration of 1.25% by weight in a homogenizer such as UltraTurrax.
- the suspension obtained is freeze-dried in order to obtain a high surface area airgel: "open" aerogel A. After drying, the aerogels are stored at 60 ° C. until the start of the esterification reaction to avoid a return to water. aerogels.
- the previously obtained aerogels undergo esterification in the gas phase.
- the aerogels are thus contacted with acyl chloride in a 2L reactor at a controlled temperature under a controlled flow of nitrogen through the reactor inlet; the reaction products (hydrochloric acid and reagent residues) being discharged through the outlet connected to a vacuum pump.
- P10-2884 / SC Thus approximately 5 g of cellulose airgel are placed on a 5 cm grid above the reagent (coupling agent) in order to avoid direct contact between the airgel and the reagent.
- Two reagents are used for each airgel: respectively a non-reactive hydrophobation agent on the polymer, C16 palmitic acid chloride of formula CH 3 (CH 2 ) 4 COCl and the coupling agent 3,3 'chloride of dithiodipropanoyl (DTDPC).
- This test aims to demonstrate the interest of graft aerogels according to the invention as reinforcing filler of rubber compositions.
- SBR diene elastomer
- compositions all correspond to the basic formulation, expressed in parts by weight per hundred parts of elastomers, phr, which follows:
- Cl is a composition not in accordance with the invention comprising an ungrafted aerogel A 'as a reinforcing filler,
- C2 is a composition not in accordance with the invention comprising an ungrafted airgel A '' as a reinforcing filler,
- C3 is a composition not in accordance with the invention comprising an aerogel A 'grafted with palmitic acid chloride, as a reinforcing filler
- P10-2884 / SC C4 is a composition according to the invention comprising an airgel A 'grafted with DTDPC, as a reinforcing filler,
- C5 is a composition not in accordance with the invention comprising a palmitic acid chloride-grafted aerogel A, as a reinforcing filler,
- C6 is a composition according to the invention comprising an airgel A "grafted with DTDPC, as a reinforcing filler.
- compositions comprise 100 phr of SBR.
- content (in phr) of cellulose microfibrils and the level of the grafted compounds were calculated using the elements of Table 3 for each composition. It will be noted that the differences in the content of cellulose microfibrils (Table 4) correspond for all the compositions to an identical percentage by volume of cellulose microfibrils (this percentage being defined by the ratio of the volume of microfibrils of cellulose to the volume total constituents of the composition)
- compositions C3 and C5 including palmitic acid chloride-grafted cellulose aerogels exhibit insignificant reinforcement (value less than 1), however these values remain very low for use in a tire rubber composition.
- the compositions according to the invention C4 and C6 have reinforcing properties corresponding to acceptable values for tire rubber compositions.
- cellulose aerogels formed of microfibrils, chemically modified by grafting on said cellulose coupling agent molecules according to the invention can surprisingly act as a reinforcing filler for rubber compositions for tires.
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR1262600A FR3000081B1 (fr) | 2012-12-21 | 2012-12-21 | Composition de caoutchouc comportant de la cellulose |
PCT/EP2013/077369 WO2014096188A1 (fr) | 2012-12-21 | 2013-12-19 | Composition de caoutchouc comportant de la cellulose |
Publications (1)
Publication Number | Publication Date |
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EP2934909A1 true EP2934909A1 (fr) | 2015-10-28 |
Family
ID=48539261
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP13814899.4A Withdrawn EP2934909A1 (fr) | 2012-12-21 | 2013-12-19 | Composition de caoutchouc comportant de la cellulose |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP2934909A1 (fr) |
FR (1) | FR3000081B1 (fr) |
WO (1) | WO2014096188A1 (fr) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10647783B2 (en) * | 2015-10-27 | 2020-05-12 | The Research Foundation For The State University Of New York | Method for preparing modified nanocrystalline cellulose |
FR3045628B1 (fr) * | 2015-12-18 | 2018-03-16 | Compagnie Generale Des Etablissements Michelin | Composition de caoutchouc comportant de la cellulose greffee |
Family Cites Families (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4483743A (en) | 1981-10-22 | 1984-11-20 | International Telephone And Telegraph Corporation | Microfibrillated cellulose |
FR2740778A1 (fr) | 1995-11-07 | 1997-05-09 | Michelin & Cie | Composition de caoutchouc a base de silice et de polymere dienique fonctionalise ayant une fonction silanol terminale |
FR2765882B1 (fr) | 1997-07-11 | 1999-09-03 | Michelin & Cie | Composition de caoutchouc a base de noir de carbone ayant de la silice fixee a sa surface et de polymere dienique fonctionnalise alcoxysilane |
ATE290565T1 (de) | 2000-02-24 | 2005-03-15 | Michelin Soc Tech | Vulkanisierbare kautschukmischung zur herstellung eines luftreifens und luftreifen, der eine solche zusammensetzung enthält |
CA2380375A1 (fr) | 2000-05-26 | 2001-12-06 | Michelin Recherche Et Technique S.A. | Composition de caoutchouc utilisable comme bande de roulement de pneumatique |
JP5357371B2 (ja) | 2000-07-31 | 2013-12-04 | コンパニー ゼネラール デ エタブリッスマン ミシュラン | タイヤ用トレッド |
FR2854404B1 (fr) | 2003-04-29 | 2005-07-01 | Michelin Soc Tech | Procede d'obtention d'un elastomere greffe a groupes fonctionnels le long de la chaine et compositions de caoutchouc |
FR2915202B1 (fr) | 2007-04-18 | 2009-07-17 | Michelin Soc Tech | Elastomere dienique couple monomodal possedant une fonction silanol en milieu de chaine, son procede d'obtention et composition de caoutchouc le contenant. |
FR2918064B1 (fr) | 2007-06-28 | 2010-11-05 | Michelin Soc Tech | Procede de preparation d'un copolymere dienique a bloc polyether, composition de caoutchouc renforcee et enveloppe de pneumatique. |
FR2918065B1 (fr) | 2007-06-28 | 2011-04-15 | Michelin Soc Tech | Procede de preparation d'un copolymere dienique a bloc polyether, composition de caoutchouc renforcee et enveloppe de pneumatique. |
JP4581116B2 (ja) * | 2007-09-10 | 2010-11-17 | 住友ゴム工業株式会社 | 加硫ゴム組成物、空気入りタイヤおよびこれらの製造方法 |
JP5178228B2 (ja) | 2008-02-15 | 2013-04-10 | 株式会社ブリヂストン | ゴム組成物及びその製造方法 |
FR2940294B1 (fr) | 2008-12-23 | 2011-02-18 | Michelin Soc Tech | Nouveau systeme d'amorcage pour polymerisation anionique de dienes conjugues, procede de preparation d'elastomeres dieniques. |
US20110136939A1 (en) * | 2009-12-08 | 2011-06-09 | Annette Lechtenboehmer | Tire with component containing cellulose |
-
2012
- 2012-12-21 FR FR1262600A patent/FR3000081B1/fr not_active Expired - Fee Related
-
2013
- 2013-12-19 EP EP13814899.4A patent/EP2934909A1/fr not_active Withdrawn
- 2013-12-19 WO PCT/EP2013/077369 patent/WO2014096188A1/fr active Application Filing
Non-Patent Citations (2)
Title |
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None * |
See also references of WO2014096188A1 * |
Also Published As
Publication number | Publication date |
---|---|
WO2014096188A1 (fr) | 2014-06-26 |
FR3000081B1 (fr) | 2015-07-17 |
FR3000081A1 (fr) | 2014-06-27 |
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