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
  • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
  • B60C9/0042—Reinforcements made of synthetic materials
• • 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
  • B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
  • B60C9/2003—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel characterised by the materials of the belt cords
  • B60C9/2009—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel characterised by the materials of the belt cords comprising plies of different materials
• • 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
  • B60C9/0064—Reinforcements comprising monofilaments
• • 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
  • B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
  • B60C9/22—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel the plies being arranged with all cords disposed along the circumference of the tyre
• • 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
  • B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
  • B60C2009/2012—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel with particular configuration of the belt cords in the respective belt 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
  • B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
  • B60C2009/2012—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel with particular configuration of the belt cords in the respective belt layers
  • B60C2009/2016—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel with particular configuration of the belt cords in the respective belt layers comprising cords at an angle of 10 to 30 degrees to the circumferential direction
• • 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
  • B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
  • B60C2009/2061—Physical properties or dimensions of the belt coating rubber
  • B60C2009/2067—Thickness
• • 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
  • B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
  • B60C2009/2074—Physical properties or dimension of the belt cord
  • B60C2009/2077—Diameters of the cords; Linear density thereof
• • 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
  • B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
  • B60C2009/2074—Physical properties or dimension of the belt cord
  • B60C2009/2083—Density in width direction
• • 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
  • B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
  • B60C9/22—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel the plies being arranged with all cords disposed along the circumference of the tyre
  • B60C2009/2238—Physical properties or dimensions of the ply coating rubber
  • B60C2009/2247—Thickness
• • 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
  • B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
  • B60C9/22—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel the plies being arranged with all cords disposed along the circumference of the tyre
  • B60C2009/2252—Physical properties or dimension of the zero degree ply cords
  • B60C2009/2257—Diameters of the cords; Linear density thereof
• • 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
  • B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
  • B60C9/22—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel the plies being arranged with all cords disposed along the circumference of the tyre
  • B60C2009/2252—Physical properties or dimension of the zero degree ply cords
  • B60C2009/2266—Density of the cords in width direction

Definitions

• the present invention relates to tires and their crown reinforcement or belt. It relates more particularly to multilayer composite laminates used in the tire belt, especially for passenger vehicles or vans.
• a radial carcass reinforcement tire for a passenger vehicle or a van has, as is known, a tread, two inextensible beads, two flexible flanks connecting the beads to the tread and a rigid crown reinforcement or "belt” (“ belt ”) arranged circumferentially between the carcass reinforcement and the tread.
• the tire belt is generally constituted by at least two rubber plies known as “working plies”, “triangulation plies” or “working reinforcement”, superimposed and crossed, most often reinforced with metal cables arranged substantially parallel to one another. relative to the others and inclined relative to the median circumferential plane, these working plies may or may not be associated with other plies and / or fabrics of rubber. These working plies have the primary function of giving the tire rigidity or high drift (“drift thrust” or “cornering”), necessary in a known manner to obtain good road handling (“handling”). ”) on a motor vehicle.
• the above belt which is particularly the case for tires that can run at high speed in a sustained manner, may further comprise a rubber sheet called “shrinking sheet” or “hooping reinforcement” which is generally reinforced by so-called “circumferential” reinforcing threads, that is to say that these reinforcing threads are disposed substantially parallel to each other and extend substantially circumferentially around the tire envelope so as to form an angle preferably included in a range of 0 to 5 ° with the median circumferential plane.
• These circumferential reinforcing son have the primary function, it is recalled, to resist the centrifugation of the top at high speed.
• Such belt structures finally consisting of a multilayer composite laminate comprising at least one hooping sheet, most often textile, and two working sheets - - Generally metallic, are well known to those skilled in the art and do not need to be described here in more detail.
• the present invention relates (according to the references given in FIGS. 1 and 2 appended) to a radial tire (1), defining three main directions, circumferential (X), axial (Y) and radial (Z), having a top (2) surmounted by a tread (3), two sidewalls (4), two beads (5), each sidewall (4) connecting each bead (5) to the top (2), a carcass reinforcement (7) anchored in each of the beads (5) and extending in the sidewalls (4) and in the apex (2), a crown reinforcement or belt (10) extending in the apex (2) in the direction circumferential (X) and located radially between the carcass reinforcement (7) and the tread (3), said belt (10) comprising a multilayer composite laminate (10a, 10b, 10c) comprising at least three superposed layers of reinforcements (110, 120 , 130), said reinforcements being in each layer unidirectional and embedded in a thickness of rubber (C1, C2, C3), with: o tread
• a second layer (10b) of rubber (C2) comprising a second row of reinforcements (120), oriented at a given beta angle, positive or negative, between 10 and 30 degrees relative to the circumferential direction (X), these reinforcements (120) said second reinforcements being metal reinforcements;
• a third layer (10c) of rubber (C3) comprising a third row of reinforcements (130), oriented at a gamma angle opposite to the angle beta, even between 10 and 30 degrees relative to the circumferential direction (X), these reinforcements (130) said third reinforcements being metal reinforcements;
• the second (120) and third (130) reinforcements consist of steel mono filaments whose diameter, denoted respectively D2 and D3, is between 0.20 mm and 0 50 mm; and in that the following characteristics, measured in the central part of the tire belt in the vulcanized state, on either side of the median plane (M) over a total axial width of 4 cm, are verified: average diameter Dl of the first reinforcements (110) is between 0.40 mm and 0.70 mm;
• o the density di of the first reinforcements (110) in the first rubber layer (C1), measured in the axial direction (Y), is between 70 and 130 son / dm;
• CT being the thermal contraction of the first reinforcements (110) of heat-shrinkable textile material, after 2 min at 185 ° C.
• this multilayer composite laminate Due to its specific construction and the combination of the above features, this multilayer composite laminate has been found to reduce tire weight and rolling resistance at reduced cost through the use of steel monofilaments that do not require prior assembly operation, all this without penalizing drift rigidity or endurance under particularly severe driving conditions. It also has the advantage of being very weakly hysteretic compared to laminates conventionally used in the belts of tires of the tourism or light truck type.
• the multilayer composite laminate according to the invention can be used as a belt-reinforcing element for any type of tire, particularly for a passenger vehicle including 4x4 vehicles and SUVs (Sport Utility Vehicles) or for a van vehicle.
• rubber or "elastomer” (both terms being considered synonymous): any type of elastomer, whether of the diene type or of the non-diene type, for example thermoplastic;
• rubber composition or “rubber composition” means a composition which comprises at least one rubber and a filler
• - “layer” a sheet, strip or any other element of relatively small thickness relative to its other dimensions, preferably whose ratio of the thickness on the largest of the other dimensions is less than 0.5, more preferably less than 0.1;
• axial direction means a direction substantially parallel to the axis of rotation of the tire;
• circumferential direction means a direction that is substantially perpendicular both to the axial direction and to a radius of the tire (in other words, tangential to a circle whose center is on the axis of rotation of the tire);
• radial direction a direction along a radius of the tire, that is to say any direction passing through the axis of rotation of the tire and substantially perpendicular to this direction, that is to say, with a perpendicular at this direction an angle not diverging by more than 5 degrees;
• oriented perpendicular to an axis or direction speaking of any element such as a reinforcement, an element which is oriented substantially perpendicular to that axis or direction, that is to say making with a perpendicular to this axis or direction an angle not more than 5 degrees apart;
• M “median circumferential plane”
• reinforcement or "reinforcing wire”: any long and thin strand, that is to say filiform, elongated, of great length relative to its cross section, especially any unitary filament, any multifilamentary fiber or any assembly of such filaments or fibers such as a plied yarn or cable, this strand or wire being rectilinear as non-rectilinear, for example twisted or corrugated, such a strand or wire being capable of reinforcing a rubber matrix (that is to say increasing the tensile properties of the matrix);
• unidirectional reinforcements reinforcements substantially parallel to each other, that is to say oriented along the same axis; - -
• laminate within the meaning of the International Patent Classification, any product having at least two layers, of flat or non-planar shape, in contact with each other, the latter being either unrelated, connected to each other; the term “bound” or “connected” must be interpreted extensively to include all connecting or joining means, in particular by gluing.
• 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 expression “from a to b” means the range from a to b (i.e., including the strict limits a and b).
• FIG. 1 very schematically represents (that is to say, without respecting a specific scale) a radial section of a tire according to the invention, for example for a tourism type vehicle. or van, whose belt comprises a multilayer composite laminate according to the invention.
• This tire (1) defining three perpendicular, circumferential (X), axial (Y) and radial (Z) directions, comprises an apex (2) surmounted by a tread (3), two sidewalls (4), two beads (5), each flank (4) connecting each bead (5) to the top (2), a carcass reinforcement (7) anchored in each of the beads (5) and extending into the flanks ( 4) and in the apex (2), a crown reinforcement or belt (10) extending in the crown (2) in the circumferential direction (X) and located radially between the carcass reinforcement (7) and the web rolling (3).
• the carcass reinforcement (7) is in a known manner constituted by at least one rubber ply reinforced by so-called "radial" textile cords arranged substantially parallel to each other and extending from one bead to the other so as to form an angle generally between 80 ° and 90 ° with the median circumferential plane M; it is here, for example, wrapped around two rods (6) in each bead (5), the upturn (8) of this armature (7) being for example disposed towards the outside of the tire (1) which is shown here mounted on its rim (9).
• the belt (10) of the tire (1) comprises a multilayer composite laminate comprising three layers (10a, 10b, 10c) superimposed with reinforcements, said reinforcements being in each layer unidirectional and embedded in a thickness of rubber (respectively Cl, C2, C3), with: o tread side, a first rubber layer (Cl) having a first row of reinforcements (110) oriented at an angle alpha (a) of -5 to +5 degrees with respect to the circumferential direction (X), these reinforcements (110) said first reinforcements being made of heat-shrinkable textile material;
• a second rubber layer (C2) comprising a second row of reinforcements (120) oriented at a given beta ( ⁇ ) angle, positive or negative, between 10 and 30 degrees; relative to the circumferential direction (X), these reinforcements (120) said second reinforcements being metal reinforcements;
• a third rubber layer (C3) comprising a third row of reinforcements (130) oriented at a gamma angle ( ⁇ ) opposite the beta angle, itself between 10 and 30 degrees relative to the circumferential direction (X), these reinforcements (130) said third reinforcements being metal reinforcements.
• angles ⁇ and ⁇ of opposite directions may be identical or different, that is to say that the second (120) and third (130) reinforcements may be arranged symmetrically or not on either side of the median circumferential plane (M) previously defined.
• the tread 3, the multilayer laminate 10 and the carcass reinforcement 7 may or may not be in contact with each other, even if these parts were deliberately separated in Figure 1, schematically, for reasons of simplification and clarity of the drawing. They could be physically separated, at least for a part of them, for example by bonding gums, well known to those skilled in the art, intended to optimize the cohesion of the assembly after baking or crosslinking.
• the second (120) and third (130) reinforcements consist, by definition, in steel monofilaments whose diameter, respectively denoted D2 and D3, is between 0.20 mm and 0.50 mm. preferably greater than 0.25 mm and less than 0.40 mm. More preferably, for optimum endurance of the tire of the invention, especially under severe driving conditions, it is preferred that D2 and D3 are in a range of 0.28 to 0.35 mm.
• the ratio of the largest dimension to the smallest dimension of the cross-section is preferably less than 50, more preferably less than 30, in particular less than 20.
• This tire of the invention has for other essential characteristics the following characteristics, measured in the central part of the tire belt in the vulcanized state, on either side of the median plane (M) over a total axial width of 4 cm (ie between - 2 cm and + 2 cm with respect to the median plane M): o the average overall diameter D1 of the first reinforcements (110) is between 0.40 mm and 0.70 mm;
• the density of the first reinforcements (110) in the first rubber layer (C1), measured in the axial direction (Y), is between 70 and 130 threads / dm (decimetre, that is, by 100 mm of rubber layer);
• the density, denoted d 2 and d 3 , of the second (120) and third (130) reinforcements in the second (C2) and third (C3) rubber layers respectively, measured in the axial direction (Y), is between 120 and 180 wires / dm;
• the average thickness Ezi of rubber separating a first reinforcement 110 (of the first layer C1) of the second reinforcement 120 (of the second layer C2) that is closest to it, measured in the radial direction (Z), is between 0.25 and 0.40 mm;
• FIG. 2 schematically shows (in a non-specific scale), in cross-section, the multilayer composite laminate (10a, 10b, 10c) used as a belt (10) in the tire (1) according to the invention of Figure 1.
• Ezi is the average of the thicknesses Ezi (3) , EZ I Q) rubber separating a first reinforcement (110) of the second reinforcement (120) which is closest thereto, these thicknesses being each measured in the radial direction Z, and averaged over a total axial distance included between - 2.0 cm and + 2.0 cm from the center of the belt (ie, for example in total about 40 measurements if there are ten reinforcements (110) per cm in the layer C1).
• Ezi is the average of the minimum distances EZ I Q separating "back to back" each first reinforcement (110) of the second reinforcement (120) which is closest to it in the radial direction Z, this average being calculated on the set of first reinforcements (110) present in the central part of the belt, in an axial gap extending between - 2 cm and + 2 cm with respect to the median plane M.
• Ez 2 is the average of the rubber thicknesses (Ez 2 ( i ) , Ez 2 ( 3 ⁇ 4 Ez 2 (3) , Ez 2 ( i ) ) separating a second reinforcement (120) from the third reinforcement (130) which is the closest, measured in the radial Z direction, this average being calculated over a total axial distance of between - 2.0 cm and + 2.0 cm from the center of the belt, expressed differently, these thicknesses represent the distances which separate "back to back" the second reinforcement (120) of the third reinforcement (130) which is closest thereto in the radial direction Z.
• Ez 2 is the average of the minimum distances Ez 2 ( i ) separating "back to back" each second reinforcement (120) of the third reinforcement (130) which is closest to it in the radial direction Z, this average being calculated on all the second reinforcements (120) present in the central part of the belt, in an axial gap extending between - 2 cm and + 2 cm with respect to the median plane M.
• the tire of the invention also satisfies the following inequalities:
• CT being the thermal contraction of the first reinforcements (110) of heat-shrinkable textile material, after 2 min at 185 ° C.
• CT is preferably less than 3.5%, more preferably less than 3%, values which have proved to be optimal for the manufacturing and design stability of the tire casings, in particular during the phases of cooking and cooling thereof.
• the size CT is measured, except for different precisions, according to the ASTM D1204-08 standard, for example on a device of the "TESTRITE" type, under a so-called standard pre-tension of 0.5 cN / tex (thus reduced to the title or density linear of the sample tested).
• the maximum of the contraction force (denoted Fc) is also measured using the - - test above, this time at a temperature of 180 ° C and under 3% elongation.
• This contraction force Fc is preferably greater than 20 N (Newton).
• a high contraction force proved to be particularly favorable to the hooping capacity of the first reinforcements (110) of heat-shrinkable textile material, vis-à-vis the crown reinforcement of the tire when the latter heats up under high speed rolling.
• the quantities CT and Fc above can be indistinctly measured on the initial textile reinforcements glued before their incorporation into the laminate and the tire, or else measured on these reinforcements once extracted from the central zone of the vulcanized tire and preferably "degummed” (i.e., rid of the rubber which coats them in the layer C1).
• any heat-shrinkable textile material that satisfies the contraction characteristics CT set forth above is suitable.
• this heat-shrinkable textile material is chosen from the group consisting of polyamides, polyesters and polyketones.
• polyamides that may be mentioned in particular are polyamides 4-6, 6, 6-6, 11 or 12.
• polyesters that may be mentioned for example PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PBT (polybutylene terephthalate) ), PBN (polybutylene naphthalate), PPT (polypropylene terephthalate), PPN (polypropylene naphthalate).
• hybrid reinforcements consisting of two (at least two) different materials, such as hybrid aramid / nylon, aramid / polyester, aramid / polyketone hybrid cords, to the extent that they verify the recommended CT characteristic.
• the heat-shrinkable textile material is a polyester, especially PET or PEN, especially a PET. More preferably still, the polyester used is a HMLS PET ("High Modulus Low Shrinkage").
• the first reinforcements of heat-shrinkable material may have any known shape, it may be certainly mono-filaments but most often they are made of multifilament fibers twisted together in the form of textile ropes.
• the diameter of the cylinder of imaginary revolution which surrounds such first reinforcements in the general case where they are not of circular cross-section (in contrast to the simple case of unit filaments) is usually understood as the overall diameter.
• the diameter D1 is between 0.45 mm and 0.65 mm;
• the density di is between 80 and 120 threads / dm, more preferably between 90 and 110 threads / dm;
• the densities d 2 and d 3 are between 130 and 170 son / dm;
• the thickness Ezi is between 0.25 and 0.35 mm, more preferably between
• the thickness Ez 2 is between 0.35 and 0.55 mm, more preferably between
• the total thickness of the multilayer composite laminate that is to say of its three layers
• the first reinforcements (110) of heat-shrinkable textile material can take any known shape, it can act for example mono elementary filaments of large diameter (for example equal to or greater than 50 ⁇ ), multifilamentary fibers (consisting of a plurality elementary filaments of small diameter, typically less than 30 ⁇ ), textile twists formed of several fibers twisted together, textile cords formed of several fibers or monofilaments cabled or twisted together.
• the second (120) and third (130) reinforcements are by definition steel monofilaments.
• the steel is a carbon steel such as those used in the steel cords for tires; but it is of course possible to use other steels, for example stainless steels, or other alloys.
• a carbon steel when a carbon steel is used, its carbon content (% by weight of steel) is in a range from 0.8% to 1.2%; according to another preferred embodiment, the carbon content of the steel is in a range from 0.6% to 0.8%.
• the invention applies in particular to steels of the steel cord type with normal resistance (called “NT” for “Normal Tensile”) or with high resistance (called “HT” for “High Tensile”), the (second and third ) carbon steel reinforcements then having a tensile strength (Rm) which is preferably greater than 2000 MPa, more preferably greater than 2500 MPa.
• the invention also applies to steels of the steel cord type with very high strength (called “SHT” for “Super High Tensile”), ultra-high strength (called “UHT” for “Ultra High Tensile” or “MT” for “Mega Tensile”), the (second and third) carbon steel reinforcements then having a tensile strength (Rm) which is preferably greater than 3000 MPa, more preferably greater than 3500 MPa.
• Rm tensile strength
• tensile strength For reinforcements (second and third) in steel, tensile strength, tensile strength Rm (in MPa) and elongation at break noted At (total elongation in%) are measured. in tension according to ISO 6892 of 1984.
• the steel used may itself be coated with a metal layer improving for example the properties of implementation of the monofilament of steel, or the properties of use of the reinforcement and / or the tire themselves, such as adhesion properties, corrosion resistance or resistance to aging.
• the steel used is covered with a layer of brass (Zn-Cu alloy) or zinc; it is recalled that during the wire manufacturing process, the coating of brass or zinc facilitates the drawing of the wire, as well as the bonding of the wire with the rubber.
• the reinforcements could be covered with a thin metal layer other than brass or zinc, whose function, for example, is to improve the corrosion resistance of these wires and / or their adhesion to the rubber, for example a thin layer of Co, Ni, Al, an alloy of two or more compounds Cu, Zn, Al, Ni, Co, Sn.
• a thin metal layer other than brass or zinc whose function, for example, is to improve the corrosion resistance of these wires and / or their adhesion to the rubber, for example a thin layer of Co, Ni, Al, an alloy of two or more compounds Cu, Zn, Al, Ni, Co, Sn.
• Each layer (C1, C2, C3) of rubber composition (or hereinafter “rubber layer”) constituting the multilayer composite laminate is based on at least one elastomer and a filler.
• the rubber is a diene rubber, that is to say for all elastomeric recall (single elastomer or elastomer mixture) which is derived, at least in part (ie, a homopolymer or a copolymer), monomers dienes that is to say monomers bearing two carbon-carbon double bonds, whether the latter are conjugated or not.
• This diene elastomer is more preferably selected from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), butadiene copolymers, isoprene copolymers, and mixtures of these elastomers.
• such copolymers being chosen in particular from the group consisting of copolymers of butadiene-styrene (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR) and isoprene-butadiene-styrene copolymers (SBIR).
• a particularly preferred embodiment consists in using an "isoprene" elastomer, that is to say a homopolymer or a copolymer of isoprene, in other words a diene elastomer chosen from the group consisting of natural rubber (NR ), the synthetic polyisoprenes (IR), the various isoprene copolymers and the mixtures of these elastomers.
• the isoprene elastomer is preferably natural rubber or synthetic polyisoprene of the cis-1,4 type.
• polyisoprenes having a content (mol%) of cis-1,4 bonds greater than 90%, more preferably still greater than 98%, are preferably used.
• each layer of rubber composition comprises 50 to 100 phr of natural rubber.
• the diene elastomer may consist, in whole or in part, of another diene elastomer such as, for example, an SBR elastomer used in or with another elastomer, for example type BR.
• Each rubber composition may comprise one or more diene elastomer (s), also all or part of the additives normally used in rubber matrices for the manufacture of tires, such as, for example, reinforcing fillers such as black rubber.
• carbon or silica coupling agents, anti-aging agents, antioxidants, plasticizers or extension oils, whether these are aromatic or non-aromatic in nature (in particular very low or non-aromatic oils, for example of the naphthenic or paraffmic type, with high or preferably low viscosity, MES or TDAE oils), plasticizing resins with a high glass transition temperature (greater than 30 ° C.), agents facilitating the implementation (processability) of the compositions in the green state, tackifying resins, anti-eversion agents, methylene acceptors and donors, such as, for example, HMT (hexamethylenetetramine) or H3M (hexamethoxymethylmelamine), reinforcing resins (such as resorcinol or bismale
• the crosslinking system of the rubber composition is a so-called vulcanization system, that is to say based on sulfur (or a sulfur-donor agent) and a primary vulcanization accelerator.
• a vulcanization system that is to say based on sulfur (or a sulfur-donor agent) and a primary vulcanization accelerator.
• sulfur or a sulfur-donor agent
• a primary vulcanization accelerator To this basic vulcanization system may be added various known secondary accelerators or vulcanization activators.
• Sulfur is used at a preferential rate of between 0.5 and 10 phr
• the primary vulcanization accelerator for example a sulfenamide
• the level of reinforcing filler for example carbon black and / or silica, is preferably greater than 30 phr, especially between 30 and 100 phr.
• Carbon blacks are suitable for all carbon blacks, in particular blacks of the HAF, ISAF, SAF type conventionally used in tires (so-called pneumatic grade blacks). Among the latter, mention will be made more particularly of carbon blacks of (ASTM) grade 300, 600 or 700 (for example N326, N330, N347, N375, N683, N772).
• Suitable silicas are in particular precipitated or pyrogenic silicas having a BET surface area of less than 450 m 2 / g, preferably from 30 to 400 m 2 / g.
• each rubber composition has, in the crosslinked state, a secant modulus in extension, at 10% elongation, which is between 4 and 25 MPa, more preferably between 4 and 20 MPa; values in particular between 5 and 15 MPa have proved particularly suitable.
• the modulus measurements are carried out in tension, unless otherwise indicated according to ASTM D 412 of 1998 (specimen "C"): the secant modulus is measured in second elongation (that is to say after an accommodation cycle).
• any suitable adhesive system for example a textile glue of the "RFL” type (resorcinol-formaldehyde), may be used.
• RRL resorcinol-formaldehyde
• - latex or equivalent for the first textile reinforcements, or for example an adhesive coating such as brass or zinc with respect to the second and third steel reinforcements; however, it is also possible to use a clear steel, that is to say uncoated steel.
• the multilayer composite laminate according to the invention makes it possible to reduce the weight and therefore the rolling resistance of the tires, at a reduced cost by using non-cabled steel monofilaments. all this and above all without degrading the rigidity of drift nor the overall endurance of these - - tires.
• the reinforcements (110) are polyamide 66 twists, each twists being 2 yarns of 140 tex which have been twisted together (on direct wiper) at 250 revolutions / meter, whose diameter D1 is equal to about 0.66 mm; their CT is equal to about 7% and their contraction force Fc is equal to about 28 N.
• the first rubber layer (Cl) coating the textile reinforcements (110) is a conventional rubber composition for calendering textile reinforcements, based on natural rubber, carbon black, a vulcanization system and usual additives; the adhesion between the polyamide twists and the rubber layer is ensured in known manner for example by a single textile glue type "RFL" (resorcinol-formaldehyde latex).
• RRL resorcinol-formaldehyde latex
• this first layer (Cl) it was well known to those skilled in the art, by a calendering operation of the textile plies (110) between two layers of rubber composition in the green state (no vulcanized) each having a thickness of about 0.25 mm.
• the metal reinforcements (120) and (130) are monolines made of carbon-based carbon (0.9% carbon and 0.2% Cr>) UHT type having a resistance Rm of the order of 3650 MPa ( breaking force of 258 N), a total elongation At of 2.3%>, whose diameter (D2, D3) is equal to 0.30 mm.
• the second (C2) and third (C3) rubber layers coating these steel monofilaments (120, 130) are constituted by a conventional composition for calendering tire belt metal plies, typically based on natural rubber, carbon black , a vulcanization system and conventional additives such as cobalt salts as adhesion promoters.
• the density of textile plies (110) in the first layer (C1), measured in the axial direction (Y), is equal to about 100 threads / dm, that (d 2 and d 3 ) respectively of the second (120) and third (130) single wire steel is equal to about 160 wires / dm.
• the average measured thickness Ezi of rubber separating these textile twists (110) from the steel monofilaments (120) was about 0.31 mm while the average thickness Ez 2 of rubber separating the steel monofilaments (120) from the other monofilaments steel (130) was close to 0.45 mm.
• the total average thickness of the laminate according to the invention, measured in the radial direction, was about 2.3 mm.
• the control tires used have the same architecture as the tires of the invention, except for the following technical characteristics: the metal reinforcements (120, 130) consist of conventional "2.30" architecture cables made of steel SHT (Rm equal to about 3170 MPa, breaking force of 450 N) consisting of 2 0.30 mm diameter wires wired together in a 14 mm pitch; the diameter (size) of these cables is 0.6 mm; they are arranged in a density of about 85 threads / dm; the average measured thickness Ezi of rubber separating the nylon twists (110) from the steel cables (120) was about 0.31 mm while the average measured thickness Ez 2 of rubber separating the steel cables (120) was of the order of 0.50 mm. The total average thickness of the laminate, measured in the radial direction, was about 3.0 mm.
• the rolling resistance was measured on a steering wheel, according to the method ISO 87-67 (1992).
• each tire was rolled at a constant speed of 80 km / h on an appropriate automatic machine (ground-plane machine marketed by MTS), by varying the load denoted "Z”.
• Z ground-plane machine marketed by MTS
• D rigidity or drifting thrust denoted
• D corrected zero drift thrust
• the invention makes it possible, in an unexpected manner, to reduce the weight and the rolling resistance of passenger or light truck tires, without harming the rigidity of drift and therefore the road behavior, while offering an endurance in running at least equivalent if not improved, even under particularly severe driving conditions.

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• 2012
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• 2013
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