Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B25/00—Layered products comprising a layer of natural or synthetic rubber
  • B32B25/04—Layered products comprising a layer of natural or synthetic rubber comprising rubber as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B25/042—Layered products comprising a layer of natural or synthetic rubber comprising rubber as the main or only constituent of a layer, which is next to another layer of the same or of a different material of natural rubber or synthetic rubber
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B25/00—Layered products comprising a layer of natural or synthetic rubber
  • B32B25/14—Layered products comprising a layer of natural or synthetic rubber comprising synthetic rubber copolymers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B25/00—Layered products comprising a layer of natural or synthetic rubber
  • B32B25/16—Layered products comprising a layer of natural or synthetic rubber comprising polydienes homopolymers or poly-halodienes homopolymers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/04—Interconnection of layers
  • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2250/00—Layers arrangement
  • B32B2250/03—3 layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2250/00—Layers arrangement
  • B32B2250/04—4 layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2250/00—Layers arrangement
  • B32B2250/05—5 or more layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2250/00—Layers arrangement
  • B32B2250/24—All layers being polymeric
  • B32B2250/248—All polymers belonging to those covered by group B32B25/00
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2270/00—Resin or rubber layer containing a blend of at least two different polymers

Definitions

• the field of the present invention is that of elastomeric laminates comprising 3 layers of rubber composition, intended in particular for use in a tire.
• a tire usually comprises a tread, two sidewalls, two beads, a carcass reinforcement passing in both flanks and anchored to the two beads, and a crown reinforcement disposed circumferentially between the tread and the carcass reinforcement.
• the tread is intended to come into contact with the running surface of the tire.
• the tire may further comprise an underlayer to the tread, the underlayer being disposed circumferentially between the tread and the carcass reinforcement, preferably between the tread and the crown reinforcement, the tread underlayer to the tread band being generally adjacent to the tread.
• the underlayer at the tread must adhere sufficiently to the tread to prevent the underlayer at the surface of the tread from becoming disengaged from the tread during the entire duration of the tread. tire life.
• the underlayer generally adheres to the tread by means of physical or chemical phenomena, such as the phenomena of interpenetration, entanglement or crosslinking of the constituent rubber compositions respectively of the tread and the sub-layer. layer to the tread. Under the appropriate conditions of implementation and firing of the rubber compositions placed against each other, these compositions are firmly bonded together and the resulting complex makes it possible to endure the stresses related to the field of application in question, in particular that of the tire.
• compositions which may be used in tread may contain an elastomeric matrix which comprises an elastomer comprising ethylene units and vinyl acetate units, as described, for example, in the patent application FR 16/63180.
• the presence of the vinyl acetate units in the elastomer makes it possible to qualify this elastomer as a polar elastomer.
• the rubber composition of a sub-layer at the tread is generally based on a highly hydrocarbon-based elastomer matrix, since the elastomer matrix is generally composed of more than 75 mol% of hydrocarbon constitutive repeating units ( in English "constitutional repeating unit").
• the level of adhesion between firstly a composition based on an elastomer matrix which is highly hydrocarbon, and secondly a second composition based on a Elastomer matrix containing a polar elastomer containing vinyl acetate units may be considered insufficient, especially for pneumatic application of the first composition as a tread of the tire and the second composition as a sub-layer to the tread .
• the sub-layer to the tread is no longer adjacent its entire length to the tread, but is separated by the connecting rubber.
• the Applicants have solved the problem by using a rubber composition which acts as a bonding gum between these two compositions. Used as an intermediate layer between the two compositions each constituting a layer in a laminate, it significantly improves the resistance of the laminate to the separation of the layers that constitute it.
• a first subject of the invention is an elastomer laminate comprising 3 layers, the first layer consisting of a rubber composition comprising a first diene elastomer matrix whose constitutive repeating units are more than 75 mol% of the hydrocarbon units,
• the second layer consisting of a rubber composition comprising a second elastomeric matrix which contains a highly saturated diene elastomer, the highly saturated diene elastomer being a diene elastomer which has more than 50 mol% of ethylene units randomly distributed in the elastomer,
• the third layer consisting of a rubber composition comprising a third elastomeric matrix that contains a polar elastomer, the polar elastomer being an elastomer comprising ethylene units and vinyl acetate units, the second layer being disposed between the first layer and the third layer; layer.
• Another object of the invention is the use of the laminate according to the invention in a tire.
• the invention also relates to a tire which comprises the laminate according to the invention.
• the invention also relates to the use of an adhesive composition identical to the rubber composition constituting the second layer of the laminate according to the invention for bonding a rubber composition identical to that constituting the first layer of the laminate according to the invention. the invention to a rubber composition identical to that constituting the third layer of the laminate according to the invention.
• 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.
• part by weight per hundred parts by weight of elastomer (or phr) is meant within the meaning of the present invention, the proportion by mass per hundred parts of elastomer present in the rubber composition considered and constituting a layer.
• 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 laminate is a product made of several layers of flat or non-planar shape, as defined by the International Patent Classification.
• the laminate according to the invention is called elastomer because it comprises 3 layers consisting of rubber compositions.
• the laminate consists of 3 layers defined according to any of the embodiments of the invention.
• the rubber composition of the second layer is different from the rubber composition of the first layer and is different from the rubber composition of the third layer.
• elastomer (or indistinctly “rubber”, the two terms being considered as synonymous) "diene”, must be understood in a known manner (one or more) elastomer derived at least in part (ie, a homopolymer or a copolymer) monomers dienes (monomers carrying two carbon-carbon double bonds, conjugated or not).
• elastomeric matrix is meant a rubber composition all the elastomers contained in the rubber composition.
• diene unit is meant a monomeric unit resulting from the insertion of a monomeric unit resulting from the polymerization of a conjugated diene monomer or a non-conjugated diene monomer, the diene unit having a carbon-carbon double bond.
• the rate of a given constitutive repetitive unit of an elastomer is equal to the ratio between the number of moles of this constitutive repeating unit present in the elastomer and the number of moles of all repeating units constituting the elastomer.
• the diene unit rate of an elastomer is the ratio between the number of moles of diene unit present in the elastomer and the number of moles of all the repeating units constituting the elastomer.
• the rate of hydrocarbon constitutive repeating units for a given elastomer E can be transcribed in the same way by replacing the symbol Ud by the symbol U H c which represents the number of moles of constituent repeating units in the elastomer E which are hydrocarbon-based.
• the rate of a repeating unit constituting an elastomer is expressed in mole percent.
• the rate of a given constitutive repetitive unit of an elastomer matrix is equal to the sum of the levels of the constitutive repetitive unit relating to each of the elastomers of the elastomer matrix and weighted by the mass fraction of the corresponding elastomer in the elastomer matrix.
• the microstructure of the elastomers is determined by 1 H NMR analysis, supplemented by 13 C NMR analysis when the resolution of the 1 H NMR spectra does not allow the assignment and quantification of all the species. Measurements are made using a 500 MHz BRUKER NMR spectrometer at frequencies of 500.43 MHz for proton observation and 125.83 MHz for carbon observation.
• a probe HRMAS 4mm z-grad for observing the proton and carbon decoupled proton mode.
• the spectra are acquired at rotation speeds of 4000Hz to 5000Hz.
• a liquid NMR probe is used to observe the proton and the carbon in decoupled mode of the proton.
• non-soluble samples are made in rotors filled with the analyzed material and a deuterated solvent allowing the swelling, in general of the deuterated chloroform (CDCl 3 ).
• the solvent used must always be deuterated and its chemical nature can be adapted by those skilled in the art.
• the amounts of material used are adjusted to obtain spectra with sufficient sensitivity and resolution.
• the soluble samples are dissolved in a deuterated solvent (approximately 25 mg of elastomer in lmL), usually deuterated chloroform (CDCl 3 ).
• a deuterated solvent approximately 25 mg of elastomer in lmL
• deuterated chloroform usually deuterated chloroform (CDCl 3 ).
• the solvent or solvent cut used must always be deuterated and its chemical nature can be adapted by those skilled in the art.
• a single pulse sequence of 30 ° is used.
• the spectral window is set to observe all of the resonance lines belonging to the analyzed molecules.
• the accumulation number is set to obtain a signal-to-noise ratio sufficient for the quantization of each pattern.
• the recycle time between each pulse is adapted to obtain a quantitative measurement.
• a 30 ° single pulse sequence is used with decoupling of the proton only during acquisition to avoid "Nuclear Overhauser” (NOE) effects and remain quantitative.
• the spectral window is set to observe all of the resonance lines belonging to the analyzed molecules.
• the accumulation number is set to obtain a signal-to-noise ratio sufficient for the quantization of each pattern.
• the recycle time between each pulse is adapted to obtain a quantitative measurement.
• the measurements are carried out at 25 ° C.
• the polar elastomer useful for the purposes of the invention is an elastomer which contains ethylene units and vinyl acetate units. It is called a polar elastomer because of the presence of vinyl acetate units in the elastomer.
• the polar elastomer contains more than 50 mol% of ethylene unit, preferably at least 55 mol% of ethylene unit.
• the polar elastomer contains at least 10 mol% of vinyl acetate unit. More preferably, the polar elastomer contains more than 50 mol% of ethylene unit, and at least 10 mol% of vinyl acetate unit.
• the polar elastomer contains at least 55 mol% of ethylene unit and at least 10 mol% of vinyl acetate unit.
• the polar elastomer is a copolymer of ethylene and vinyl acetate, also known as EVA.
• the polar elastomer useful for the purposes of the invention may be a mixture of polar elastomers which differ from each other by their macrostructure or their microstructure, in particular by the respective molar content of their constituent repeating units.
• the highly saturated diene elastomer useful for the purposes of the invention is a diene elastomer which contains more than 50 mol% of ethylene units distributed randomly in the elastomer.
• the highly saturated diene elastomer contains, in the molar percentages indicated below, the units UA, UB, UC, UD, optionally, UE units of the following formula
• n, o, p and q are numbers ranging from 0 to 100
• the highly saturated diene elastomer has at least one of the following criteria, and preferably all:
• q is equal to 0.
• the highly saturated diene elastomer contains as monomeric units only the units UA, UB, UC, UD and EU according to their respective molar percentage m, n, o, p and q, of preferably all different from 0.
• the highly saturated diene elastomer contains, as monomeric units, only the units UA, UB, UC and UD according to their respective molar percentage m, n, o and p, preferably all different from 0.
• the ethylene units UA present in the highly saturated diene elastomer preferably represent more than 70 mol% of all the monomer units of the highly saturated diene elastomer.
• the diene units comprising a carbon-carbon double bond and present in the highly saturated diene elastomer are preferably 1,3-diene units having 4 to 12 carbon atoms. , especially 1,3-butadiene units. More preferably, the highly saturated diene elastomer is a copolymer of ethylene and 1,3-butadiene.
• the highly saturated diene elastomer useful for the purposes of the invention may be a mixture of highly saturated diene elastomers which differ from each other by their macrostructure or their microstructure, in particular by the respective molar ratio of their constituent repetitive units.
• the highly saturated diene elastomer can be obtained according to various synthesis methods known to those skilled in the art, in particular according to the target values of m, n, o, p, q and r.
• the highly saturated diene elastomer can be prepared by copolymerization of at least one conjugated diene monomer and ethylene and according to known synthetic methods, in particular in the presence of a catalyst system comprising a metallocene complex.
• Catalyst systems based on metallocene complexes which catalytic systems are described in documents EP I 092 731 A1, EP 1 554 321 A1, EP 1 656 400 A1, EP 1 829 901 A1, EP 1 954, are described. 705 A1, EP 1 957 506 A1, on behalf of the Applicants.
• the highly saturated diene elastomer can be prepared in accordance with the documents cited above, by adapting the polymerization conditions by means known to those skilled in the art, so as to preferably reach values of number average molecular weight (Mn). at least 60,000 g / mol (conventionally determined by size exclusion chromatography (SEC) coupled to differential refractometric detection from calibration with polystyrene standards).
• Mn number average molecular weight
• SEC size exclusion chromatography
• the polymerization time can be significantly increased so that the conversion to monomer is greater, thus leading to the obtaining of molar masses of at least 60,000 g / mol.
• the stoichiometry of the alkylating agent with respect to the metallocene complex (s) is decreased, so as to reduce the chain transfer reactions and to obtain molar masses of at least 60 000 g / mol.
• the second elastomer matrix has the essential characteristic of comprising a highly saturated diene elastomer as defined above.
• the presence of the highly saturated diene elastomer in the second elastomeric matrix of the second layer improves the peel separation resistance of the first layer and the third layer.
• the second layer thus acts as an adhesive or adhesive composition for bonding the first layer and the third layer.
• the level of highly saturated diene elastomer in the second elastomer matrix is equal to or greater than 50 phr.
• the level of highly saturated diene elastomer in the second elastomer matrix is at least 90 phr.
• the second elastomer matrix further contains the polar elastomer as defined above.
• the mass fraction of the polar elastomer in the second elastomer matrix is less than or equal to the mass fraction of the highly saturated diene elastomer in the second elastomer matrix.
• the presence of the polar elastomer in the second elastomer matrix allows excellent resistance to the separation of the third layer and the second layer and good resistance to separation of the first layer and the second layer.
• the highly saturated diene elastomer and the polar elastomer preferably constitute the second elastomer matrix alone.
• the second elastomer matrix preferably consists of a mixture of the highly saturated diene elastomer and the polar elastomer.
• the second elastomer matrix is the highly saturated diene elastomer, which is to say that the highly saturated diene elastomer alone forms the second elastomer matrix or that the level of Highly saturated diene elastomer in the second elastomer matrix is 100 phr.
• the use of the only highly saturated diene elastomer in the second elastomer matrix provides access to a laminate which has excellent resistance to the separation of the first layer and the second layer and good resistance to the separation of the third layer and the second layer.
• the first elastomeric matrix that composes the rubber composition of the first layer is a diene elastomeric matrix, since it comprises one or more diene elastomers. Its essential characteristic is that it is highly hydrocarbon-based, since more than 75 mol% of the repeating units that make up the elastomer matrix are hydrocarbon-based.
• the repeating units constituting the elastomer matrix are typically the monomeric units which constitute the elastomers of the elastomer matrix, as well as the units which result from a modification of the monomer units in the case where one or more of the elastomers of the matrix have been modified. after the polymerization reaction.
• the repeating units constituting the first diene elastomer matrix are more than 90 mol% of the hydrocarbon units.
• the first elastomer matrix also contains a diene unit molar level greater than the diene unit molar ratio of the second elastomer matrix.
• the first diene elastomer matrix is also a highly unsaturated elastomer matrix, since it preferably has a diene unit molar level of greater than 50%.
• the first diene elastomer matrix is an elastomer chosen from the group of diene elastomers consisting of polybutadienes, polyisoprenes, butadiene copolymers, isoprene copolymers and their mixtures.
• the elastomer chosen from the group of diene elastomers consisting of polybutadienes, polyisoprenes, butadiene copolymers, isoprene copolymers and their mixtures is present in the matrix A at a preferential rate of 100 phr. means that it alone forms the matrix A according to this preferred embodiment.
• the matrix A is a highly unsaturated diene elastomer, that is to say an elastomer containing more than 50 mol% of diene units.
• the first diene elastomer matrix is a high cis polyisoprene having a 1,4-cis bond ratio greater than 90%, preferably a natural rubber. This more preferred embodiment is particularly suitable in the case where the laminate is used in a tire, more particularly when the first layer constitutes part or all of a sub-layer of a tread.
• the third polymer matrix that composes the rubber composition of the third layer comprises a polar elastomer as defined above.
• the third elastomer matrix further contains the highly saturated diene elastomer as defined above.
• the mass fraction of the highly saturated diene elastomer in the third elastomer matrix is smaller than the mass fraction of the polar elastomer in the third elastomer matrix.
• the polar elastomer is present in the third matrix at a rate greater than 50 phr, preferably at a level of at least 90 phr.
• the rate of the polar elastomer is 100 phr, which is to say that the polar elastomer alone forms the third elastomer matrix.
• the constituent rubber composition of any one of the three layers preferably comprises a reinforcing filler, particularly when the laminate is used in a tire.
• the reinforcing filler may be any type of so-called reinforcing filler, known for its ability to reinforce a rubber composition that can be used for the manufacture of tires, for example an organic filler such as carbon black, a reinforcing inorganic filler such as silica which is associated in a known manner a coupling agent, or a mixture of these two types of charge.
• Such a reinforcing filler typically consists of nanoparticles whose average size (in mass) is less than one micrometer, generally less than 500 nm, most often between 20 and 200 nm, in particular and more preferably between 20 and 150 nm.
• Suitable carbon blacks are all carbon blacks, especially blacks conventionally used in tires or their treads (so-called pneumatic grade blacks). Among the latter, there will be mentioned more particularly the reinforcing carbon blacks of the series 100, 200, 300, or the series blacks 500, 600 or 700 (ASTM grades), such as, for example, the blacks N115, N134, N234, N326, N330. , N339, N347, N375, N550, N683, N772). These carbon blacks can be used in the isolated state, as commercially available, or in any other form, for example as a carrier for some of the rubber additives used.
• Reinforcing inorganic filler means any inorganic or mineral filler, irrespective of its color and origin (natural or synthetic), also called “white” filler, “clear” filler or even “non-black” filler. as opposed to carbon black, capable of reinforcing on its own, without any other means than an intermediate coupling agent, a rubber composition intended for the manufacture of pneumatic tires, in other words able to replace, in its function reinforcement, a conventional carbon black of pneumatic grade; such a filler is generally characterized, in known manner, by the presence of hydroxyl groups (-OH) on its surface.
• -OH hydroxyl groups
• Suitable reinforcing inorganic fillers are in particular mineral fillers of the siliceous type, preferentially silica (SiO 2 ).
• 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 / g, especially between 60 and
• HDS highly dispersible precipitated silicas
• Hi-Sil silica EZ150G from the company PPG, the "Zeopol” silicas 8715, 8745 and 8755 from the Huber Company, the high surface area silicas as described in the application WO 03/016387.
• 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, specifically according to the French standard NF ISO 9277 of December 1996 (multipoint volumetric method (5 points) - gas: nitrogen - degassing: time at 160 ° C - relative pressure range p / po: 0.05 at 0.17).
• the CTAB specific surface is the external surface determined according to the French standard NF T 45-007 of November 1987 (method B).
• reinforcing inorganic filler is present indifferent, whether in the form of powder, microbeads, granules or beads.
• reinforcing inorganic filler is also understood to mean mixtures of different reinforcing inorganic fillers, in particular of highly dispersible silicas as described above.
• a coupling agent is used in a well-known manner, in particular an at least bifunctional silane (or bonding agent) intended to ensure a sufficient connection, of a chemical nature and / or or physical, between the inorganic filler (surface of its particles) and the elastomeric matrix.
• an at least bifunctional silane or bonding agent
• organosilanes or at least bifunctional polyorganosiloxanes are used.
• silane polysulfides are more particularly of bis (disulfide, trisulfide or tetrasulfide) of bis (alkoxyl (Ci-C 4) alkyl (Ci-C 4) alkyl-silyl (Ci-C 4 )), such as polysulfides of bis (3-trimethoxysilylpropyl) or bis (3-triethoxysilylpropyl).
• TESPT bis (3-triethoxysilylpropyl) tetrasulfide
• TESPD bis (3-triethoxysilylpropyl) tetrasulfide
• TESPD bis (3-triethoxysilylpropyl) tetrasulfide
• TESPD bis (3-triethoxysilylpropyl) tetrasulfide
• TESPD bis (3-triethoxysilylpropyl) tetrasulfide
• TESPD bis (3-triethoxysilylpropyl) tetrasulfide
• TESPD bis (triethoxysilylpropyl) disulfide, in abbreviated form
• TESPD bis (triethoxysilylpropyl) disulfide
• TESPD bis (triethoxysilylpropyl) disulfide
• As a coupling agent it is also possible to use a silane carrying at least
• the double bond is preferably activated by a carbonyl group CO.
• the silane carrying at least one activated ethylenic double bond is preferably a silane carrying a methacrylate function such as 3- (trimethoxysilyl) propyl methacrylate or 3- (triethoxysilyl) propyl methacrylate.
• the content of coupling agent is advantageously less than 20 phr (parts by weight per hundred parts of elastomer matrix present in the rubber composition considered and constituting a layer), it being understood that it is generally desirable to use them. the least possible.
• the level of coupling agent is from 0.5% to 15% by weight relative to the amount of inorganic filler. Its level is preferably between 0.5 and 12 phr, more preferably in a range from 3 to 10 phr. This level is readily adjusted by those skilled in the art depending on the level of inorganic filler used in the rubber composition.
• a polymer which carries reactive functions with the acetate groups of the polar elastomer, such as epoxide functional groups is preferably used as a coupling agent.
• carboxylic As such, one can use copolymers containing monomer units of a terminal olefin such as ethylene or alphaolefin, as well as monomer units of a monomer carrying an epoxide or carboxylic function, such as certain acrylate or methacrylate monomers.
• copolymers of ethylene and glycidyl acrylate particularly suitable copolymers of ethylene and glycidyl acrylate, copolymers of ethylene and glycidyl methacrylate, copolymers of ethylene, vinyl acetate and glycidyl methacrylate and copolymers of ethylene, vinyl acetate and glycidyl acrylate.
• These polymers are notably commercially available under the name "Lotader” from Arkema, "Elvaloy” from Du Pont and “Ingetabond” from Sumitomo.
• the polymer is used as a coupling agent in the rubber composition at a rate which is generally adjusted according to the amount of inorganic filler in the rubber composition and which typically ranges from 5% to 30% by weight relative to the weight of the inorganic reinforcing filler, in particular silica.
• each of the rubber compositions respectively constituting the 3 layers of the laminate comprises a reinforcing filler, preferably a carbon black or a silica or a mixture of carbon black and silica.
• the reinforcing filler of the third layer preferably comprises a silica, the reinforcing filler of the rubber compositions of the second and third layers being a carbon black or a mixture of carbon black. carbon and silica.
• the level of reinforcing filler in each of the laminate rubber compositions can vary to a large extent, for example depending on the nature of the elastomeric matrix or reinforcing filler in the rubber composition or the amount of plasticizer in the rubber composition. . These variables are adjusted by those skilled in the art according to the use that is made of the laminate, especially in a tire. This rate can therefore range from 20 to 200 phr.
• the nature of the Reinforcing filler in the rubber composition of the first layer and the third layer and its rate are chosen by those skilled in the art in accordance with the particular conditions of this use.
• the reinforcing filler content is preferably 20 to 50 phr for the first layer, from 30 to 80 phr for the third layer, from 5 to 80 phr and more preferably from 5 to 50 phr for the second layer.
• the level of reinforcing filler in the rubber composition of the second layer preferably varies from 5 to 80 phr, more preferably from 5 to 50 phr.
• the rubber composition of the second layer comprises a level of reinforcing filler less than or equal to the reinforcing filler content of the rubber composition of the first layer.
• the constitutive rubber composition of any one of the 3 layers can also contain, in addition to the coupling agents, coupling activators, inorganic filler agents or, more generally, processing aid agents capable of in a known manner, thanks to an improvement in dispersion of the filler in the rubber matrix and a lowering of the viscosity of the rubber composition, to improve its ability to implement in the green state.
• It may also comprise all or part of the usual additives usually used in elastomer compositions intended to constitute mixtures of finished articles of rubber such as tires, for example pigments, protective agents such as anti-ozone waxes.
• additives usually used in elastomer compositions intended to constitute mixtures of finished articles of rubber such as tires for example pigments, protective agents such as anti-ozone waxes.
• the constituent rubber composition of any one of the 3 layers preferably comprises a crosslinking system.
• the rubber compositions of the three layers contain a crosslinking system.
• a sulfur-based crosslinking system commonly known as a vulcanization system, or a peroxide-based crosslinking system is preferably used.
• the crosslinking system is preferably based on peroxides.
• the rubber compositions that are useful for the purposes of the invention may also comprise plasticizers, for example extender oils of aromatic or non-aromatic nature, in particular very slightly or non-aromatic oils (eg hydrogenated paraffinic oils, naphthenic oils, MES or TDAE oils), vegetable oils, in particular glycerol esters such as glycerol trioleate, hydrocarbon plasticizing resins having a high Tg, preferably greater than 30 ° C, as described for example in WO 2005 / 087859, WO 2006/061064 and WO 2007/017060.
• the plasticizer content is adjusted by those skilled in the art depending on the viscosity and desired properties of the rubber composition which are determined by the use of the rubber composition.
• the viscosity of the rubber composition itself depends on many variables, such as the viscosity of the elastomeric matrix, the level of reinforcing filler, interactions that may exist between the elastomeric matrix and the reinforcing filler. Thus the skilled person with his general knowledge chooses the appropriate plasticizer rate taking into account these different variables.
• the rubber composition of the second useful layer of the invention contains a plasticizer, it preferably contains at most 20 phr, more preferably less than 10 phr, even more preferably less than 5 phr. These preferred embodiments make it possible to achieve even more remarkable levels of adhesion between the first and third layers thanks to the interphase constituted by the second layer.
• the rubber composition of the second layer is devoid of plasticizer. This advantageous embodiment from the point of view of the adhesion performance is particularly suitable for the rubber compositions constituting the second layer which are weakly loaded, in particular those comprising at most 50 phr of reinforcing filler.
• the rubber compositions useful for the purposes of the invention may be manufactured in suitable mixers, using two successive preparation phases well known to those skilled in the art: a first phase of work or thermomechanical mixing (so-called “non-productive phase”). ”) At high temperature, followed by a second phase of mechanical work (so-called” productive "phase at lower temperature.
• the so-called “non-productive" phase is generally carried out in a single thermomechanical step during which the constituents are introduced into a suitable mixer such as a conventional internal mixer.
• a suitable mixer such as a conventional internal mixer.
• the total mixing time in this non-productive phase is preferably between 1 and 15 minutes, until a maximum temperature of between 130 ° C. and 200 ° C. is reached.
• the "productive" phase After cooling the mixture obtained, one proceeds to the "productive" phase during which it is then incorporated in an external mixer such as a roll mill maintained at low temperature (for example between 40 ° C and 100 ° C), the crosslinking system (typically sulfur and accelerator or peroxide).
• the crosslinking system typically sulfur and accelerator or peroxide.
• the mixture is then mixed for a few minutes, for example between 2 and 15 min at a temperature below 110 ° C, for example between 40 ° C and 100 ° C.
• the "non-productive" phase is generally carried out in a single thermomechanical step during which the elastomer matrix is introduced into a suitable mixer such as a conventional internal mixer. , if necessary the reinforcing filler, the coupling agent, other additives with the exception of the peroxide crosslinking system, at a temperature of between 20 ° C. and 100 ° C. and preferably between 25 ° C. and 100 ° C.
• the total mixing time, in this non-productive phase is preferably between 2 and 15 min, until a maximum temperature of between 100 ° C and 180 ° C is reached.
• the crosslinking system for example with peroxides
• low temperature typically below 100 ° C.
• second phase productive phase
• compositions prepared are then calendered, for example in the form of a layer, in particular for a characterization in the laboratory.
• the constituent rubber compositions of the layers are affixed in the green state, one on the other.
• the layers are preferably applied hot, the layers being in the green state.
• the hot application of the layers in the green state is carried out at a temperature which is compatible with the chemical nature of the layers, that is to say at a temperature which does not cause for example prematurely the crosslinking of the layers .
• a temperature above ambient (20 ° C) and not exceeding 80 ° C is entirely appropriate.
• the laminate according to the invention may comprise several preferred ranges of thickness.
• the first and third layers may have a thickness of at least 2 mm, preferably between 3 and 10 mm.
• the preferential thickness may be between 2 and 20 mm for the first and third layers.
• the preferred thickness of the first and third layers may be between 2 and 100 mm.
• the second layer preferably has a thickness ranging from 60 ⁇ m to a few millimeters, for example from 100 ⁇ m to 5 mm. The thickness is adjusted according to the particular conditions of use of the laminate.
• the layers are preferably formed by applying the rubber composition in the form of a dissolution composed of a volume of solvent.
• the layers may be arranged one on the other by successive application of the layers, for example on a clothing drum conventionally used in the manufacture of a tire (or envelope) of a tire.
• the first layer is deposited on the drum, the second layer on the first layer, the third layer on the second layer.
• the laminate can be either in the green state (before crosslinking or vulcanization) or in the fired state (after crosslinking or vulcanization).
• the laminate can be manufactured prior to the manufacture of the tire or during the manufacture of the tire.
• the preformed laminate formed and in the green state can be applied to the tire by depositing it, for example, on the carcass or crown reinforcement of the tire, also in the green state.
• the first layer may be deposited for example on the carcass or crown reinforcement of the tire, also in the green state, then the second layer on the third layer and the third layer on the second layer, the first, second and third layers being in the raw state.
• the laminate can be used in a tire, the tire comprising a tread, two sidewalls, two beads, a carcass reinforcement passing in both sides and anchored to the two beads, and a crown reinforcement arranged circumferentially between the tread and the carcass reinforcement.
• the laminate is used in a tire so that the third layer forms part or all of the tread of the tire and the first layer a part or all of a tire. under layer to the tread.
• the third layer constitutes the entire tread and the first layer all of a sub-layer to the tread.
• the third layer in the laminate is used as a sub-layer to the tread of a tire, it is preferably not intended to come into contact with the tread surface of the tire.
• the tire which is provided with the laminate and which represents another object of the invention may be in the baked state or in the green state.
• Another object of the invention is the use of a diene rubber composition as an adhesive composition for bonding two compositions.
• the two compositions to be bonded are respectively identical to the diene rubber compositions constituting the first layer and the third layer defined according to any of the described embodiments of the laminate according to the invention.
• the adhesive composition is identical to the diene rubber composition constituting the second layer defined according to any of the described embodiments of the laminate according to the invention.
• compositions whose formulation is shown in Tables 1 and 2 are prepared according to the process described above.
• a first series concerns compositions C1, C2-1 and C3-1.
• a second series concerns compositions C1, C2-2 and C3-2.
• composition C1 is an illustration of a composition of the first layer of a laminate according to the invention.
• compositions C2-1 and C2-2 are an illustration of a composition of the second layer (C2) of a laminate according to the invention.
• Compositions C3-1 and C3-2 are an illustration of a composition of the third layer (C3) of a laminate according to the invention.
• Adhesion tests were conducted to test the ability of the ethylene-vinyl acetate (C3) copolymer-based adhesive layer to adhere after baking to a layer of ethylene copolymer and 1,3-butadiene (C2), and this same layer based on copolymer of ethylene and 1,3 butadiene (C2) to adhere to a layer based on a matrix mainly diene (Cl).
• C3 ethylene-vinyl acetate
• C2 1,3-butadiene
• the adhesion is measured between the two layers C1 and C3, between the two layers C1 and C2 and between the two layers C2 and C3.
• the value of the adhesion measurement between the two layers C1 and C3 is retained as the control value, since the laminate comprising the only two layers C1 and C3 is not in accordance with the invention because of the absence of the layer C2.
• the value of the adhesion measurement of the control is 100.
• results are expressed in performance index.
• An index greater than 100 indicates a greater improvement in membership.
• Adhesive properties are measured according to the peel test described below. ll-l. Description of the peel test:
• the peel test pieces (of the 180 ° peel type) were made by stacking the following products:
• a layer C1 (between 2 and 3 mm thick)
• a layer C1 (between 2 and 3 mm thick)
• a rupture primer is placed at the interface between one of the layers of gums and the adhesive layer.
• test pieces are then fired at 170 ° C. for 20 minutes and at a pressure of 16 bar in a plate press.
• Strips of 30mm width were cut to the cutter. Both sides of the breakout primer were then placed into the jaws of an Instron brand traction machine. The tests are carried out at 60 ° C. after steaming of the test pieces for 30 minutes. The pulling speed is 100mm / min. The tensile forces are recorded and these are standardized by the width of the specimen. A force curve per unit width in N / mm is obtained as a function of the moving crosshead displacement of the traction machine (between 0 and 200 mm). The retained adhesion value corresponds to the average value calculated on the curve.
• the adhesion performance indices on the one hand between the first layer (C1) and the second layer (C2, in this case C2-1 and C2-2), on the other hand between the second layer ( C2, in this case C2-1 and C2-2) and the third layer (C3, in this case C3-1 and C3-2 respectively) are the highest relative to the controls. They are even up to 60 times higher than those of the witness.
• the results of the peel tests confirm the advantage of using a layer C2 based on a highly saturated diene elastomer to bond a layer C3 based on a polar elastomer containing ethylene units and vinyl acetate units on a layer Cl based on a very predominantly diene matrix.
• Ethylene / vinyl acetate copolymer (EVA) marketed by Arkema under the reference Evatane 42-60.
• the copolymer has a mole percent ethylene monomer equal to 81% and a mole percent vinyl acetate monomer equal to 19%;
• N-cyclohexylthiophthalimide (Vulkalent G) from the company Lanxess)
• Ethylene / vinyl acetate (EVA) copolymer sold by Arlanxeo under the reference LEVAPREN 500.
• the copolymer has a molar percentage of ethylene monomer equal to 75% and a molar percentage of vinyl acetate monomer equal to 25%. % .;

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• 2018
  • 2018-12-05 WO PCT/FR2018/053113 patent/WO2019110924A1/fr unknown
  • 2018-12-05 EP EP18830919.9A patent/EP3720700A1/de active Pending

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