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
• • 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
  • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
  • B60C11/0041—Tyre tread bands; Tread patterns; Anti-skid inserts comprising different tread rubber layers
  • B60C11/005—Tyre tread bands; Tread patterns; Anti-skid inserts comprising different tread rubber layers with cap and base layers
• • 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
  • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
  • B60C9/18—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
  • C08K5/0016—Plasticisers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L91/00—Compositions of oils, fats or waxes; Compositions of derivatives thereof
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T152/00—Resilient tires and wheels
  • Y10T152/10—Tires, resilient
  • Y10T152/10495—Pneumatic tire or inner tube
  • Y10T152/10765—Characterized by belt or breaker structure

Definitions

• the present invention relates to the elastomeric layers used in the crown ("crown") of tires and compositions based on thermoplastic elastomers (TPE), used for the manufacture of such tires.
• TPE thermoplastic elastomers
• a constant objective of tire manufacturers is to increase the rigidity of tire drift, in particular by the incorporation of a sub-layer of high rigidity under the tread.
• the rigidity of this underlayer makes it possible, in known manner, to improve the handling behavior of the tires.
• the invention relates to a radial tire for a motor vehicle, comprising:
• a crown comprising a tread provided with at least one radially outer portion intended to come into contact with the road;
• crown reinforcement or belt disposed circumferentially between the radially outer portion of the tread and the carcass reinforcement; o a radially inner elastomeric layer called "underlayer", of different formulation formulation of the radially outer portion of the tread, this sublayer itself being disposed circumferentially between the radially outer portion of the tread and the carcass reinforcement,
• said underlayer comprises at least one thermoplastic elastomer, said thermoplastic elastomer being a block copolymer comprising at least one minus one elastomeric block and at least one thermoplastic block, and the total content of thermoplastic elastomer being in a range of 65 to 100 phr (parts by weight per hundred parts of elastomer).
• the composition of this underlayer provides an increased drift rigidity. Moreover, it is difficult to achieve this goal without penalizing too strongly the rolling resistance since an increase in rigidity is generally accompanied by an increase in hysteresis, and conversely, the decrease in hysteresis often assumes a loss in rigidity.
• the underlayment compositions of the tires according to the invention make it possible to increase the rigidity of drift without any appreciable increase in hysteresis.
• the invention relates to a tire as defined above, wherein the number average molecular weight of thermoplastic elastomer F is between 30,000 and 500,000 g / mol.
• the invention relates to a tire as defined above, wherein the one or more elastomeric blocks of the block copolymer are chosen from elastomers having a glass transition temperature of less than 25 ° C .; preferably selected from the group consisting of ethylenic elastomers, diene elastomers and mixtures thereof, more preferably from diene elastomers. More preferably, the invention relates to a tire as defined above, in which the elastomeric block or blocks of the block copolymer are diene elastomers derived from isoprene, butadiene or a mixture thereof. .
• the invention relates to a tire as defined above, wherein the thermoplastic block or blocks of the block copolymer are chosen from polymers having a glass transition temperature greater than 80 ° C. and, in the case where a semicrystalline thermoplastic block, a melting temperature above 80 ° C; and in particular, the thermoplastic block (s) of the block copolymer are chosen from the group consisting of polyolefms, polyurethanes, polyamides, polyesters, polyacetals, polyethers, phenylene polysulfides, polyfluoro compounds, polystyrenes, polycarbonates, polysulfones, polymethyl methacrylate, polyetherimide, thermoplastic copolymers and mixtures thereof; and more preferably, the thermoplastic block (s) of the block copolymer are chosen from polystyrenes.
• the invention relates to a tire as defined above, wherein the thermoplastic elastomer or elastomers are selected from the group consisting of thermoplastic elastomers styrene / butadiene (SB), styrene / isoprene (SI) styrene / butadiene / isoprene (SBI), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / butadiene / isoprene / styrene (SBIS) and mixtures of these copolymers.
• SB thermoplastic elastomers
• SI styrene / isoprene
• SI styrene / butadiene
• SI styrene / isoprene / styren
• the invention relates to a tire as defined above, wherein the thermoplastic elastomer is the only elastomer of the underlayer.
• the invention relates to a tire as defined above, wherein the underlayer further comprises a non-thermoplastic elastomer at a rate of at most 35 phr.
• the invention relates to a tire as defined above, in which the underlayer further comprises at least one thermoplastic polymer other than an elastomer, which is preferentially chosen from poly (para) polymers. phenylene ether).
• the level of thermoplastic polymer is less than 40 phr.
• the invention relates more particularly to tires intended to equip non-motorized vehicles such as bicycles, or tourism-type motor vehicles, SUV ("Sport Utility Vehicles"), two wheels (including motorcycles), airplanes, as industrial vehicles chosen from vans, "heavy goods vehicles” - that is, metros, buses, road transport vehicles (trucks, tractors, trailers), off-the-road vehicles such as agricultural or civil engineering -, other transport or handling vehicles.
• non-motorized vehicles such as bicycles, or tourism-type motor vehicles, SUV ("Sport Utility Vehicles"), two wheels (including motorcycles), airplanes, as industrial vehicles chosen from vans, "heavy goods vehicles” - that is, metros, buses, road transport vehicles (trucks, tractors, trailers), off-the-road vehicles such as agricultural or civil engineering -, other transport or handling vehicles.
• the underlayer is disposed circumferentially inside the crown of the tire, between on the one hand the most radially outer portion of its tread, that is to say the portion intended to come into contact with the road during driving, and secondly the crown reinforcement.
• Underlay means any rubber part radially external to the crown reinforcement of the tire which does not extend to the outside of the tire, which is not in contact with the air or an inflation gas. other terms which is therefore located inside the tread or between the tread and the belt (or crown reinforcement) of the tire. It should therefore be understood that this sub-layer can be arranged:
• tread in the tread itself, but in this case radially under the carved portion (that is to say radially internally relative to this portion) tread which is intended to come into contact with the road during the rolling of the tire, throughout the life of the tire; - Or under the tread (that is to say radially internally relative to this tread), between the tread and the belt (or crown reinforcement).
• this underlayer is the single layer lying between the tread and the crown reinforcement, or lying inside the tread.
• Figures 1 and 2 appended represent in radial section, very schematically (in particular without respecting a specific scale), two examples preferential tire tires for a motor vehicle with a radial carcass reinforcement, according to the invention.
• FIG. 1 illustrates a first possible embodiment of the invention, according to which the underlayer (8) is integrated with the tread (3) itself, but arranged under the portion (3a) of the tread which is intended to come into contact with the road when driving, to form what is commonly called a sub-layer of a tread.
• the tread is also commonly known to those skilled in the art of "cap-base” tread, the term “cap” designating the sculpted portion of the tread intended to come into contact with the road and the term “base” designating the non-carved portion of the tread, of different formulation, which is in turn not intended to come into contact with the road.
• the tire (1) schematically comprises a vertex (2) having a tread (3) (for simplicity, with a very simple sculpture) whose radially outer portion (3 a) is intended in contact with the road, two non-extensible beads (4) in which is anchored a carcass reinforcement (6).
• the top (2), joined to said beads (4) by two sides (5), is known per se reinforced by a crown reinforcement or "belt” (7) at least partly metallic and radially external to the carcass reinforcement (6).
• a tire belt generally consists of at least two superimposed belt plies, sometimes called “working” or “crossed” plies, whose reinforcing elements or “reinforcements” are arranged substantially parallel to each other.
• Each of these two crossed plies consists of a rubber matrix or "calendering rubber” coating the reinforcements.
• the crossed plies may be supplemented by various other plies or layers of auxiliary rubber, of varying widths depending on the case, with or without reinforcements; we will mention examples of simple rubber cushions, so-called “protection” plies responsible for protecting the rest of the belt from external aggression, perforations, or so-called “hooping” plies comprising reinforcements oriented substantially in the circumferential direction ( so-called “zero degree” plies), whether radially external or internal with respect to the crossed plies.
• reinforcement is generally used in the form of steel cords or textile cords.
• "textile cords" consisting of fine threads assembled together by cabling or twisting.
• the carcass reinforcement (6) is here anchored in each bead (4) by winding around two rods (4a, 4b), the upturn (6a, 6b) of the armature (6) being for example disposed towards the outside of the tire (1) which is shown here mounted on its rim (9).
• the carcass reinforcement (6) consists of at least one ply reinforced by radial textile cords, that is to say that these cords are arranged substantially parallel to each other and extend from a bead to the other so as to form an angle of between 80 ° and 90 ° with the median circumferential plane (plane perpendicular to the axis of rotation of the tire which is located halfway between the two beads 4 and passes through the middle of the crown frame 7).
• this tire (1) further comprises, in known manner, a layer (10) of rubber or inner elastomer (commonly called “inner liner” or “inner liner”) which defines the radially inner face of the tire and which is intended for protecting the carcass ply from the diffusion of air from the interior space to the tire.
• This tire example (1) according to the invention of Figure 1 is characterized in that the base portion (8) of its tread (3) is constituted by the underlayer which is described in detail in the following.
• FIG. 2 illustrates another possible embodiment of the invention, according to which the underlayer (8) is external to the tread (ie, distinct from the tread), disposed this time, always in the top (2), below the tread (ie, radially inwardly from the latter) and above the belt (ie, radially externally to the latter), in other words between the tread (3) and the belt (7).
• the underlayer (8) is external to the tread (ie, distinct from the tread), disposed this time, always in the top (2), below the tread (ie, radially inwardly from the latter) and above the belt (ie, radially externally to the latter), in other words between the tread (3) and the belt (7).
• the underlayer thanks to its improved drift rigidity properties, is likely to contribute to a better behavior ("handling") of vehicles equipped with such tires .
• This underlayer preferably has a thickness of between 0.2 and 3 mm, more preferably between 0.5 and 2.5 mm, and even more preferably between 1 and 2.5 mm.
• thermoplastic elastomers in English “phr" means within the meaning of the present patent application, part by weight per hundred parts of elastomer, thermoplastic and non-thermoplastics combined.
• thermoplastic elastomers TPE are part of the elastomers.
• 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 (that is, terminals a and b excluded). ) while any range of values designated by the expression “from a to b” signifies the range of values from a to b (that is to say, including the strict limits a and b).
• the tire according to the invention has the essential feature of being provided with an elastomer layer called "underlayer" of different formulation of the outer portion, carved, of the tread, said underlayer comprising minus a thermoplastic elastomer, said thermoplastic elastomer being a block copolymer comprising at least one elastomer block and at least one thermoplastic block, and the total content of thermoplastic elastomer being in a range of from 65 to 100 phr (parts by weight per cent parts of elastomer).
• TPE Thermoplastic elastomer
• thermoplastic elastomers have an intermediate structure between thermoplastic polymers and elastomers. These are copolymers blocks, consisting of rigid blocks, thermoplastic, connected by flexible blocks, elastomers.
• thermoplastic elastomer used for the implementation of the invention is a block copolymer whose chemical nature of thermoplastic blocks and elastomers may vary.
• the number-average molecular weight (denoted Mn) of the TPE is preferably between 30,000 and 500,000 g / mol, more preferably between 40,000 and 400,000 g / mol.
• Mn number-average molecular weight
• the number-average molecular weight (Mn) of the TPE elastomer is determined in known manner, by steric exclusion chromatography (SEC).
• SEC steric exclusion chromatography
• the sample is solubilized beforehand in tetrahydrofuran at a concentration of approximately 1 g / l; then the solution is filtered on 0.45 ⁇ porosity filter before injection.
• the apparatus used is a "WATERS alliance" chromatographic chain.
• the elution solvent is tetrahydrofuran, the flow rate 0.7 ml / min, the system temperature 35 ° C and the analysis time 90 min.
• a set of four WATERS columns in series, of trade names "STYRAGEL"("HMW7",”HMW6E” and two “HT6E”) is used.
• the injected volume of the solution of the polymer sample is 100 ⁇ .
• the detector is a "WATERS 2410" differential refractometer and its associated chromatographic data exploitation software is the “WATERS” system.
• MILLENNIUM MILLENNIUM ".
• the calculated average molar masses relate to a calibration curve made with polystyrene standards. The conditions are adaptable by those skilled in the art.
• the TPE when reference is made to the glass transition temperature of the TPE, it is the Tg relative to the elastomeric block.
• the TPE preferably has a glass transition temperature ("Tg") which is preferably less than or equal to 25 ° C, more preferably less than or equal to 10 ° C.
• Tg glass transition temperature
• a value of Tg higher than these minima can reduce the performance of the underlayer when used at very low temperatures; for such use, the Tg of the TPE is more preferably still less than or equal to -10 ° C.
• the Tg of the TPE is greater than -100 ° C.
• the TPEs have two glass transition temperature peaks (Tg, measured according to ASTM D3418), the lowest temperature being relative to the elastomeric portion of the TPE, and the highest temperature being relative. to the thermoplastic part of the TPE.
• Tg glass transition temperature
• the soft blocks of the TPEs are defined by a Tg lower than the ambient temperature (25 ° C), while the rigid blocks have a Tg greater than 80 ° C.
• the TPE must be provided with sufficiently incompatible blocks (that is to say different because of their mass, their polarity or their respective Tg) to maintain their own properties of elastomer or thermoplastic block.
• the TPE may be copolymers with a small number of blocks (less than 5, typically 2 or 3), in which case these blocks preferably have high masses, greater than 15000 g / mol.
• These TPEs can be, for example, diblock copolymers, comprising a thermoplastic block and an elastomeric block. They are often also triblock elastomers with two rigid segments connected by a flexible segment. The rigid and flexible segments can be arranged linearly, star or connected. Typically, each of these segments or blocks often contains at least more than 5, usually more than 10 base units (e.g., styrene units and butadiene units for a styrene / butadiene / styrene block copolymer).
• base units e.g., styrene units and butadiene units for a styrene / butadiene / styrene block copolymer.
• the TPE may also comprise a large number of blocks (more than 30, typically from 50 to 500) smaller, in which case these blocks preferably have low masses, for example from 500 to 5000 g / mol, these TPEs will be called multiblock TPEs later, and are a sequence of elastomeric blocks - thermoplastic blocks.
• the TPE is in a linear form.
• TPE is a diblock copolymer: thermoplastic block / elastomeric block.
• the TPE can also be a triblock copolymer: thermoplastic block / elastomer block / thermoplastic block, that is to say a central elastomer block and two terminal thermoplastic blocks, at each of the two ends of the elastomeric block.
• the multiblock TPE can be a linear sequence of elastomeric blocks - thermoplastic blocks.
• the TPE useful for the purposes of the invention is in a star shape at least three branches.
• the TPE may then consist of a stellate elastomer block with at least three branches and a thermoplastic block, located at the end of each of the branches of the elastomeric block.
• the number of branches of the central elastomer can vary, for example from 3 to 12, and preferably from 3 to 6.
• the TPE is in a branched form or dendrimer.
• the TPE can then consist of a connected elastomeric block or dendrimer and a thermoplastic block, located at the end of the branches of the dendrimer elastomer block.
• the elastomeric blocks of the TPE for the purposes of the invention may be all the elastomers known to those skilled in the art. They generally have a Tg less than 25 ° C, preferably less than 10 ° C, more preferably less than 0 ° C and very preferably less than -10 ° C. Also preferably, the TPE block elastomer block is greater than -100 ° C.
• the elastomeric portion of the TPE does not contain ethylenic unsaturation, it will be a saturated elastomer block.
• the elastomeric block of the TPE comprises ethylenic unsaturations (that is to say carbon-carbon double bonds), then we will speak of an unsaturated or diene elastomer block.
• a saturated elastomer block consists of a polymer block obtained by the polymerization of at least one (that is to say one or more) ethylenic monomer, that is to say comprising a double bond carbon - carbon.
• polyalkylene blocks such as ethylene-propylene or ethylene-butylene random copolymers.
• saturated elastomeric blocks can also be obtained by hydrogenation of unsaturated elastomeric blocks. It may also be aliphatic blocks from the family of polyethers, polyesters, or polycarbonates.
• this elastomeric block of the TPE is preferably composed mainly of ethylenic units.
• a majority is meant a weight ratio of ethylenic monomer highest relative to the total weight of the elastomeric block, and preferably a weight of more than 50%, more preferably more than 75% and even more preferably more than 85%. %.
• Conjugated C 4 -C 14 dienes may be copolymerized with the ethylenic monomers. In this case, it is a question of random copolymers.
• these conjugated dienes are chosen from isoprene, butadiene, 1-methylbutadiene, 2-methylbutadiene, 2,3-dimethyl-1,3-butadiene, 2,4-dimethyl-1,3- butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, 2,3-dimethyl-1 , 3-pentadiene, 1,3-hexadiene, 2-methyl-1,3-hexadiene, 3-methyl-1,3-hexadiene, 4-methyl-1,3-hexadiene, 5-methyl- 1,3-hexadiene, 2,3- dimethyl-1,3-hexadiene, 2,4-dimethyl-1,3
• the conjugated diene is isoprene or a mixture containing isoprene.
• this elastomer block of the TPE is preferably composed mainly of a diene elastomer part.
• a majority is meant a weight ratio of the highest diene monomer relative to the total weight of the elastomer block, and preferably a weight content of more than 50%, more preferably of more than 75% and even more preferably of more than 85%. %.
• the unsaturation of the unsaturated elastomer block can come from a monomer comprising a double bond and a cyclic unsaturation, this is the case for example in polynorbornene.
• C 4 -C 14 conjugated dienes may be polymerized or copolymerized to form a diene elastomer block.
• these conjugated dienes are chosen from isoprene, butadiene, piperylene, 1-methylbutadiene, 2-methylbutadiene, 2,3-dimethyl-1,3-butadiene and 2,4-dimethyl-1.
• the monomers polymerized to form the elastomer part of the TPE may be randomly copolymerized with at least one other monomer so as to form an elastomer block.
• the molar fraction of polymerized monomer other than an ethylenic monomer, relative to the total number of Elastomeric block patterns must be such that this block retains its elastomeric properties.
• the molar fraction of this other comonomer may range from 0 to 50%, more preferably from 0 to 45% and even more preferably from 0 to 40%.
• this other monomer capable of copolymerizing with the first monomer can be chosen from the ethylenic monomers as defined above (for example ethylene), the diene monomers, more particularly the conjugated diene monomers having 4 to 14 carbon atoms as defined above (for example butadiene), the monomers of the vinylaromatic type having from 8 to 20 carbon atoms as defined below or else it may be a monomer such as vinyl acetate).
• the comonomer is of the vinylaromatic type, it advantageously represents a fraction in units on the total number of units of the thermoplastic block from 0 to 50%, preferably ranging from 0 to 45% and even more preferentially ranging from 0 to 40%.
• vinylaromatic compounds are particularly suitable styrenic monomers mentioned above, namely methylstyrenes, para-tert-butylstyrene, chlorostyrenes, bromostyrenes, fluoro styrenes or para-hydroxy-styrene.
• the vinylaromatic comonomer is styrene.
• the elastomer blocks of the TPE have in total a number-average molecular weight ("Mn") ranging from 25,000 g / mol to 350,000 g / mol, preferably from 35,000 g / mol to 250,000 g / mol so as to give the TPE good elastomeric properties and sufficient mechanical strength and compatible with the use of underlayer tire.
• Mn number-average molecular weight
• the elastomeric block may also be a block comprising several types of ethylenic, diene or styrenic monomers as defined above.
• the elastomeric block may also consist of several elastomeric blocks as defined above.
• the elastomer block of the TPE will preferably comprise double bonds. carbon - carbon. It is preferably an unsaturated elastomer block, thus forming a TPE said unsaturated TPE.
• the glass transition temperature characteristic (Tg) of the thermoplastic rigid block will be used. This characteristic is well known to those skilled in the art. It allows in particular to choose the temperature of industrial implementation (transformation). In the case of an amorphous polymer (or a polymer block), the implementation temperature is chosen to be substantially greater than the Tg. In the specific case of a polymer (or a polymer block) semi - Crystalline, we can observe a melting temperature then higher than the glass transition temperature. In this case, it is rather the melting temperature (Tf) which makes it possible to choose the implementation temperature of the polymer (or polymer block) considered. Thus, later, when we speak of "Tg (or Tf, if any)", we must consider that this is the temperature used to choose the temperature of implementation.
• the TPE elastomers comprise one or more thermoplastic block (s) preferably having a Tg (or Tf, where appropriate) greater than or equal to 80 ° C. and consisting of ) from polymerized monomers.
• this thermoplastic block has a Tg (or Tf, if applicable) in a range of 80 ° C to 250 ° C.
• the Tg (or Tf, if appropriate) of this thermoplastic block is preferably from 80 ° C to 200 ° C, more preferably from 80 ° C to 180 ° C.
• the proportion of thermoplastic blocks with respect to the TPE is determined firstly by the thermoplastic properties that must present said copolymer.
• Thermoplastic blocks having a Tg (or Tf, if appropriate) greater than or equal to 80 ° C are preferably present in proportions sufficient to preserve the thermoplastic nature of the elastomer according to the invention.
• the minimum rate of thermoplastic blocks having a Tg (or Tf, the case where applicable) greater than or equal to 80 ° C in the TPE may vary depending on the conditions of use of the copolymer.
• thermoplastic blocks having a Tg (or Tf, if any) greater than or equal to 80 ° C may be formed from polymerized monomers of various kinds, in particular, they may constitute the following blocks or mixtures thereof:
• polyolefins polyethylene, polypropylene
• polyethers polyethylene oxide, polyphenylene ether
• FEP polyfluoro
• thermoplastic copolymers such as acrylonitrile-butadiene-styrene copolymer (ABS).
• thermoplastic blocks having a Tg (or Tf, if appropriate) greater than or equal to 80 ° C can also be obtained from monomers chosen from the following compounds and their mixtures:
• acenaphthylene one skilled in the art can for example refer to the article by Z. Fodor and J.P. Kennedy, Polymer Bulletin 1992 29 (6) 697-705;
• indene and its derivatives such as, for example, 2-methylindene, 3-methylindene, 4-methylindene, dimethylindene, 2-phenylindene, 3-phenylindene and 4- phenylindene; those skilled in the art will for example be able to refer to the patent document US4946899, by the inventors Kennedy, Puskas, Kaszas and Hager and to the documents JE Puskas, G. Kaszas, JP Kennedy, WG Hager Journal of Polymer Science Part A: Polymer Chemistry (1992) 30, 41 and JP Kennedy, N. Meguriya, B. Keszler, Macromolecules (1991) 24 (25), 6572-6577;
• Polystyrenes are obtained from styrenic monomers.
• styrene monomer is to be understood in the present description any monomer comprising styrene, unsubstituted as substituted; among the substituted styrenes may be mentioned, for example, methylstyrenes (for example ⁇ -methylstyrene, m-methylstyrene or p-methylstyrene, alpha-methylstyrene, alpha-2-dimethylstyrene, alpha-4-dimethylstyrene or diphenylethylene), para-tert-butylstyrene, chlorostyrenes (e.g., ⁇ -chlorostyrene, m-chlorostyrene, p-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene or 2,4,6-dichlorostyrene).
• bromostyrenes eg, o-bromostyrene, m-bromostyrene, p-bromostyrene, 2,4-dibromostyrene, 2,6-dibromostyrene or 2,4,6-tribromostyrene
• fluorostyrenes eg o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, 2,4-difluorostyrene, 2,6-difluoro styrene or 2,4,6-trifluorostyrene
• the weight content of styrene in the TPE elastomer is between 5% and 50%. Below the minimum indicated, the thermoplastic nature of the elastomer is likely to decrease significantly while above the maximum recommended, the elasticity of the underlayer can be affected. For these reasons, the styrene content is more preferably between 10% and 40%.
• the polymerized monomer as defined above may be copolymerized with at least one other monomer so as to form a thermoplastic block having a Tg (or Tf, if appropriate) as defined. above.
• this other monomer capable of copolymerizing with the polymerized monomer may be chosen from diene monomers, more particularly conjugated diene monomers having 4 to 14 carbon atoms, and vinylaromatic-type monomers having from 8 to 20 carbon atoms, as defined in the part relating to the elastomeric block.
• the thermoplastic blocks of the TPE have in total a number-average molecular weight ("Mn") ranging from 5,000 g / mol to 150,000 g / mol, so as to give the TPE good properties. elastomeric and sufficient mechanical strength and compatible with the use of tire underlayer.
• Mn number-average molecular weight
• thermoplastic block may also consist of several thermoplastic blocks as defined above. 1.1.4. Examples of TPE
• the TPE is a copolymer whose elastomer portion is saturated, and comprising styrenic blocks and alkylene blocks.
• the alkylene blocks are preferably ethylene, propylene or butylene.
• this TPE elastomer is chosen from the following group, consisting of diblock copolymers, linear or starred triblocks: styrene / ethylene / butylene (SEB), styrene / ethylene / propylene (SEP), styrene / ethylene / ethylene / propylene (SEEP ), styrene / ethylene / butylene / styrene (SEBS), styrene / ethylene / propylene / styrene (SEPS), styrene / ethylene / ethylene / propylene / styrene (SEEPS), styrene / isobuty
• the TPE is a copolymer whose elastomer part is unsaturated, and which comprises styrenic blocks and diene blocks, these diene blocks being in particular isoprene or butadiene blocks.
• this TPE elastomer is chosen from the following group, consisting of diblock copolymers, linear triblocks or styrene / butadiene (SB), styrene / isoprene (SI), styrene / butadiene / isoprene (SBI), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / butadiene / isoprene / styrene (SBIS) and mixtures of these copolymers.
• SB styrene / isoprene
• SI styrene / butadiene / isoprene
• SBIS styrenelastomer
• the TPE is a linear or star-shaped copolymer whose elastomer part comprises a saturated part and an unsaturated part such as for example styrene / butadiene / butylene (SBB), styrene / butadiene / butylene / styrene (SBBS) ) or a mixture of these copolymers.
• SBB styrene / butadiene / butylene
• SBBS styrene / butadiene / butylene / styrene
• multiblock TPEs mention may be made of copolymers comprising random copolymer blocks of ethylene and propylene / polypropylene, polybutadiene / polyurethane (TPU), polyether / polyester (COPE), polyether / polyamide (PEBA).
• TPU polybutadiene / polyurethane
• COPE polyether / polyester
• PEBA polyether / polyamide
• TPE elastomers As examples of commercially available TPE elastomers, mention may be made of the elastomers of SEPS, SEEPS or SEBS type sold by Kraton under the name "Kraton G” (eg G1650, G1651, G1654, G1730 products).
• Kraton G eg G1650, G1651, G1654, G1730 products.
• thermoplastic elastomer (s) constitute the majority fraction by weight; they then represent at least 65%, preferably at least 70% by weight, more preferably at least 75% by weight of all the elastomers present in the elastomer composition. Also preferably, the TPE elastomer (s) represent (s) at least 95% (in particular 100%) by weight of all the elastomers present in the elastomer composition.
• the total amount of TPE elastomer is in a range from 65 to 100 phr, preferably from 70 to 100 phr and especially from 75 to 100 phr. Also preferably, the composition contains from 95 to 100 phr of TPE elastomer.
• the TPE elastomer or elastomers are preferably the one or only elastomers of the underlayer.
• thermoplastic elastomer or elastomers described above are sufficient on their own for the underlayment according to the invention to be usable.
• composition of the underlayer according to the invention may comprise at least one (that is to say one or more) diene rubber as non-thermoplastic elastomer, this diene rubber may be used alone, or in cutting with at least one (i.e. one or more) other non-thermoplastic rubber or elastomer.
• the optional total non-thermoplastic elastomer content is in a range from 0 to 35 phr, preferably from 0 to 30 phr, more preferably from 0 to 25 phr, and more preferably from 0 to 5 phr. . Also preferably, the underlayer of the tire according to the invention does not contain a non-thermoplastic elastomer.
• elastomer or “diene” rubber it is to be understood in a known way (one or more elastomers) are derived at least in part (ie a homopolymer or a copolymer) of diene monomers (monomers carrying two carbon-carbon double bonds, conjugated or otherwise).
• diene elastomers can be classified in two categories: “essentially unsaturated” or “essentially saturated”.
• the term “essentially unsaturated” is generally understood to mean a diene elastomer derived at least in part from conjugated diene monomers having a level of units or units of diene origin (conjugated dienes) which is greater than 15% (% by weight). mole).
• the term “highly unsaturated” diene elastomer is particularly understood to mean a diene elastomer having a content of units of diene origin (conjugated dienes) which is greater than 50%.
• diene elastomers such as certain butyl rubbers or copolymers of dienes and alpha olefins EPDM type can be described as "essentially saturated" diene elastomers (low or very low diene origin ratio). low, always less than 15%).
• diene elastomers low or very low diene origin ratio. low, always less than 15%.
• diene elastomer Any type of diene elastomer may be used in the invention.
• the composition contains a vulcanization system, essentially unsaturated elastomers, in particular types (a) and (b) above, are preferably used for the manufacture of the underlayer of the tire according to the present 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 "vinyl-toluene" commercial mixture, para-tertiarybutylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene.
• the copolymers may contain between 99% and 20% by weight of diene units and between 1% and 80% by weight of vinylaromatic units.
• the elastomers may have any microstructure which is a function of the polymerization conditions used, in particular the presence or absence of a modifying and / or randomizing agent and the amounts of modifying and / or randomizing agent used.
• the elastomers may for example 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.
• a coupling agent for example, there may be mentioned for example functional groups comprising a C-Sn bond or amino functional groups such as benzophenone for example;
• a reinforcing inorganic filler such as silica, mention may be made, for example, of silanol or polysiloxane functional groups having a silanol end (as described, for example, in FR 2,740,778 or US Pat. No.
• alkoxysilane groups such as 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 groups polyethers (as described for example in EP 1,127,909 or US 6,503,973).
• functionalized elastomers mention may also be made of elastomers (such as SBR, BR, NR or IR) of the epoxidized type.
• thermoplastic elastomer described above is sufficient on its own for the underlayment according to the invention to be usable.
• a reinforcing filler When a reinforcing filler is used, one can use any type of filler usually used for the manufacture of tires, for example an organic filler such as carbon black, an inorganic filler such as silica, or a cutting of these two types of filler, including a cut of carbon black and silica.
• an organic filler such as carbon black
• an inorganic filler such as silica
• a cutting of these two types of filler including a cut of carbon black and silica.
• carbon blacks are particularly suitable all carbon blacks conventionally used in tires (so-called pneumatic grade black).
• pneumatic grade black For example, mention will be made more particularly of reinforcing carbon blacks of the series 100, 200 or 300 (ASTM grades), such as for example the blacks NI 15, N134, N234, N326, N330, N339, N347, N375, or else according to targeted applications, blacks of higher series (for example N660, N683, N772), or even N990.
• any inorganic or mineral filler (whatever its color and its origin (natural or synthetic), also called “white” charge, charge “clear” or “non-black filler” as opposed to carbon black, capable of reinforcing on its own, with no other means than an intermediate coupling agent, a rubber composition for manufacturing tire, in other words able to replace, in its reinforcing function, a conventional carbon black pneumatic grade, such a charge is generally characterized, in known manner, by the presence of hydroxyl groups (-OH) at its area.
• -OH hydroxyl groups
• the physical state under which the reinforcing inorganic filler is present is indifferent, whether in the form of powder, microbeads, granules, beads or any other suitable densified form.
• the term "reinforcing inorganic filler” also refers to mixtures of different reinforcing inorganic fillers, in particular highly dispersible siliceous and / or aluminous fillers as described below.
• reinforcing inorganic fillers are especially suitable mineral fillers of the siliceous type, in particular of silica (SiO 2 ), or of the aluminous type, in particular of alumina (Al 2 O 3 ).
• 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.
• highly dispersible precipitated silicas called "HDS"
• a coupling agent or bonding agent at least bifunctional for ensuring a sufficient connection, chemical and / or physical, between the inorganic filler (surface of its particles) and the elastomer, in particular organosilanes or bifunctional polyorganosiloxanes.
• the reinforcing charge volume ratio, optional, in the composition is in a range from 0 to 20%, which corresponds to a rate of 0 to 50 pce for a composition without plasticizer.
• the composition comprises less than 30 phr of reinforcing filler and more preferably less than 10 phr.
• the composition of the underlayer does not contain a reinforcing filler. 1.4.
• the underlayer described above may furthermore comprise the various additives usually present in the sublayers known to those skilled in the art.
• one or more additives chosen from protective agents such as antioxidants or antiozonants, anti-UV agents, the various agents of implementation or other stabilizers, or the promoters able to promote the adhesion to the rest of the structure will be chosen. of the pneumatic object.
• the underlayer does not contain all these additives at the same time and even more preferably, the underlayer contains none of these agents.
• the composition of the sublayer of the invention may contain a crosslinking system known to those skilled in the art.
• the composition does not contain a crosslinking system.
• the composition of the underlayer of the invention may contain one or more inert micrometric fillers such as lamellar fillers known to those skilled in the art.
• the composition contains no micron charge.
• the composition of the underlayer of the invention may contain a plasticizer, such as an extender oil (or plasticizing oil) or a plasticizing resin whose function is to facilitate the implementation. of the underlayer, particularly its integration with the tire by a lowering of the module and an increase in the tackifiant power.
• a plasticizer such as an extender oil (or plasticizing oil) or a plasticizing resin whose function is to facilitate the implementation. of the underlayer, particularly its integration with the tire by a lowering of the module and an increase in the tackifiant power.
• Any extension oil preferably of a slightly polar nature, capable of extending and plasticizing elastomers, especially thermoplastics, may be used. At room temperature (23 ° C), these oils, more or less viscous, are liquids (that is to say, as a reminder, substances having the ability to eventually take the shape of their container), as opposed in particular to resins or rubbers which are inherently solid.
• the extender oil is selected from the group consisting of paraffmic oils, such as low viscosity paraffmic oil (PABV).
• PABV low viscosity paraffmic oil
• the level of plasticizer varies from 0 to 80 phr, more preferably from 0 to 50 phr, more preferably still from 0 to 30 phr, and in particular less than 10 phr, according to the Tg and the module. referred to for the underlayment.
• the composition of the underlayer does not contain a plasticizer.
• the composition of the underlayer may also comprise, in a minority weight fraction relative to the block elastomer, polymers other than elastomers, such as, for example, thermoplastic polymers.
• polymers other than elastomers such as, for example, thermoplastic polymers.
• the total content of non-elastomeric thermoplastic polymers is less than 40 phr, preferably between 5 and 30 phr, and more preferably between 10 and 25 phr.
• These thermoplastic polymers may in particular be polymers of poly (para-phenylene ether) (abbreviated as "EPP").
• thermoplastic polymers PPE are well known to those skilled in the art, they are solid resins at room temperature (20 ° C) compatible with styrenic polymers, which have in particular used to increase the Tg of TPE elastomers whose thermoplastic block is a styrenic block (see for example "Thermal, Mechanical and Morphological Analyzes of Poly (2,6-dimethyl-1,4-phenylene oxide) / Styrene-Butadiene-Styrene Blends", Tucker, Barlow and Paul, Macromolecules, 1988, 21). , 1678-1685).
• TPE elastomers can be used in the usual way for
• TPE by extrusion or molding, for example from a raw material available in the form of beads or granules.
• the underlayer for the tire according to the invention is prepared in the usual manner, for example, by incorporating the various components into a twin-screw extruder, so as to carry out the melting of the matrix and an incorporation of all the components. ingredients, then use a die to make the profile.
• This underlayer may be mounted on a tire in the usual manner, said tire comprising in addition to the underlayer necessary for the purposes of the invention, a tread, a crown and a crown reinforcement. and preferably, two flanks and two beads, and a carcass reinforcement anchored to the two beads and extending from one side to the other.
• Tire underlayer compositions according to the invention were prepared as indicated above.
• Tires were then prepared according to the usual methods, with the components known to those skilled in the art: a tread, an underlayer, a top, two flanks and two beads, a carcass reinforcement anchored to two beads, and a crown reinforcement, the underlayer being that described for the purposes of the present invention.
• the properties of the tires according to the invention can be evaluated by tests carried out on tires or from tests on samples of the undercoat composition as indicated hereinafter.
• drift thrust offers tires a very good level of handling behavior on a motor vehicle.
• each tire tested is mounted on a wheel of suitable size and inflated to its reference pressure. It is rolled at a constant speed of 80 km / h on an appropriate automatic machine (machine type "ground-plane” marketed by the company MTS).
• the load denoted “Z” is varied at a drift angle of 1 degree, and the rigidity or drifting pressure denoted “D" (corrected for zero drift thrust) is measured in known manner, by recording at sensor help the transverse force on the wheel as a function of this load Z; the drift thrust is the slope at the origin of the curve D (Z).
• the results are presented in base 100, corresponding to the drift rigidity of the control; a result greater than 100 thus showing an increased rigidity of drift.
• tires according to the invention were prepared as indicated above and compared to a control tire provided with a usual underlayer prepared according to a usual method known to those skilled in the art.
• the compositions of the adhesion layers are shown in Table 1 below.
• composition A-1 is a conventional undercoat composition, here constituting the control, while the compositions A-2, A-3 and A-4 correspond to underlayer compositions for the purposes of the invention. 'invention. It is possible to note in these compositions the great economy of means, related to the use of TPE elastomers in the composition of the underlayer. Indeed, it is noted that the TPE elastomer is sufficient on its own, as the only component of the composition of the underlayer, for this underlayer to be used according to the invention.

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• 2011
  • 2011-05-12 FR FR1154094A patent/FR2975045B1/fr not_active Expired - Fee Related
• 2012
  • 2012-05-04 JP JP2014509690A patent/JP6286348B2/ja not_active Expired - Fee Related
  • 2012-05-04 CN CN201280022970.0A patent/CN103517812A/zh active Pending
  • 2012-05-04 WO PCT/EP2012/058236 patent/WO2012152688A1/fr not_active Ceased
  • 2012-05-04 EP EP12718249.1A patent/EP2707231B1/fr active Active
  • 2012-05-04 US US14/116,059 patent/US20140083589A1/en not_active Abandoned

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