WO2002096677A1 - Pneu pouvant rouler a plat - Google Patents

Pneu pouvant rouler a plat Download PDF

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Publication number
WO2002096677A1
WO2002096677A1 PCT/US2001/017257 US0117257W WO02096677A1 WO 2002096677 A1 WO2002096677 A1 WO 2002096677A1 US 0117257 W US0117257 W US 0117257W WO 02096677 A1 WO02096677 A1 WO 02096677A1
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WO
WIPO (PCT)
Prior art keywords
tire
insert
rubber
acid
metal salt
Prior art date
Application number
PCT/US2001/017257
Other languages
English (en)
Inventor
Michael Grah
Original Assignee
Societe De Technologie Michelin
Michelin Recherche Et Technique S.A.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Societe De Technologie Michelin, Michelin Recherche Et Technique S.A. filed Critical Societe De Technologie Michelin
Priority to PCT/US2001/017257 priority Critical patent/WO2002096677A1/fr
Priority to PCT/US2002/017174 priority patent/WO2002096672A2/fr
Priority to AU2002316181A priority patent/AU2002316181A1/en
Publication of WO2002096677A1 publication Critical patent/WO2002096677A1/fr

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Classifications

    • 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
    • C08K5/04—Oxygen-containing compounds
    • C08K5/09—Carboxylic acids; Metal salts thereof; Anhydrides thereof
    • C08K5/098—Metal salts of carboxylic acids
    • 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
    • B60C1/0025—Compositions of the sidewalls
    • 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
    • B60C17/00—Tyres characterised by means enabling restricted operation in damaged or deflated condition; Accessories therefor
    • B60C17/0009—Tyres characterised by means enabling restricted operation in damaged or deflated condition; Accessories therefor comprising sidewall rubber inserts, e.g. crescent shaped inserts
    • 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
    • B60C17/00—Tyres characterised by means enabling restricted operation in damaged or deflated condition; Accessories therefor
    • B60C17/0009—Tyres characterised by means enabling restricted operation in damaged or deflated condition; Accessories therefor comprising sidewall rubber inserts, e.g. crescent shaped inserts
    • B60C17/0018—Tyres characterised by means enabling restricted operation in damaged or deflated condition; Accessories therefor comprising sidewall rubber inserts, e.g. crescent shaped inserts two or more inserts in each sidewall portion
    • 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
    • C08K5/04—Oxygen-containing compounds
    • C08K5/14—Peroxides

Definitions

  • the invention is in the field of pneumatic tires, and specifically is in the field of pneumatic tires that function after losing all inflation pressure.
  • This tire reduces the need for a spare tire and ancillary equipment. Therefore, in some cases it may achieve substantial savings in vehicle weight, and increase the space for other automotive systems and cargo.
  • Numerous variations of runflat tires have been developed. These involve changes to the structure of the tire itself and modifications to the rim to hold and support the flat tire. Each variation is limited by restrictions on vehicle speed, length of travel, zero inflation pressure handling, and the magnitude of the lateral accelerations that force the bead of the tire off the rim seat.
  • a number of general features of runflat tires have been disclosed that permit some degree of operation of a vehicle when tire pressure is lost.
  • These features include thickened tire sidewalls, sidewall reinforcing plies, tire bead seat and vehicle rim configuration modifications, tire sidewall to rim flange contact, and tire belt package edge modifications.
  • Each of these features can be used to help solve known runflat performance problems.
  • one feature of some runflat tires is thickened sidewalls to support the vehicle after loss of inflation pressure.
  • Such a sidewall as the tire is viewed in cross-section, presents a crescent-shaped mass of rubber on the inside of the tire's sidewalls. On complete deflation of the tire, the crescent-shaped mass is put into compression while the carcass cord reinforcement is in tension, thereby preventing total collapse of the sidewall.
  • the invention is a pneumatic tire comprising at least one reinforced radial carcass layer having a crown portion and a pair of end portions each anchored in a respective spaced-apart bead; a tread outward of said crown portion of said carcass layer and a reinforced belt portion between said tread and said carcass layer; a pair of sidewall portions each adjacent said carcass layer and extending radially from a respective bead to a respective lateral edge of said tread; an inner-liner interior to said carcass layer to retain air inside a cavity of the tire; each one of said pair of sidewalls having a crescent-shaped insert for providing continuous running with the loss of inflation pressure.
  • Said tire includes a first crescent-shaped insert placed to the interior of said at least one carcass layer, said first insert having a first compound which includes a sulfur-accelerated system for curing; a second crescent-shaped insert placed radially inward of the first insert and having a common interface with said first crescent-shaped insert, said second insert having a second compound which includes a peroxide catalyst and a metal salt of a carboxylic acid, preferably an acrylic acid, and wherein said second crescent-shaped insert has a higher modulus of elasticity than said first crescent-shaped insert.
  • the metal salt of the acrylic acid comprises zinc dimethacrylate.
  • the tire is a bias-ply tire.
  • Figure 1 is a cross-section of a runflat tire showing crescent-shaped reinforcing inserts according to one embodiment of the invention.
  • the present invention comprises a tire with a support system comprising a set of two inserts interior to each of the sidewalls.
  • the inserts provide sufficient support for the tire to allow continued normal operation of the vehicle until the tire can be repaired or replaced. In some circumstances, the vehicle might have to be driven dozens of miles before service can be obtained.
  • the first insert, which is next to the sidewall has a lower modulus of elasticity (is less stiff) than the second crescent-shaped insert. Placing a stiff insert next to the sidewall might lead to cracking of the sidewall.
  • the first insert is made of an elastomer (i.e., rubber) cured with a sulfur system
  • the second insert is made of an elastomer (i.e., rubber) cured with a peroxide co-agent system.
  • the higher stiffness of the second insert means it will flex less as the tire rolls in the uninflated condition. Less flexure means less heat is generated, heat which could act to break down the structural components of the tire. Less flexure of the sidewall of the uninflated tire also improves the handling characteristics of the vehicle.
  • the higher stiffness of the second insert also means that a thinner insert can be used as compared to the prior art. A thinner insert has less mass, and causes less hysteretic heat build-up when the tire is in the normally inflated condition.
  • the peroxide co-agent curing system contains a metal salt of a carboxylic acid.
  • a metal salt of a carboxylic acid In one embodiment of the invention, certain polymerizable metal salts of alpha, beta-ethylenically unsaturated carboxylic acids are employed. These include methacrylic acid, ethacrylic acid, acrylic acid, cinnamic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and the like.
  • saturated aliphatic carboxylic acids such as acetic acid, butyric acid, lauric acid, palmitic acid, stearic acid and the like, higher unsaturated aliphatic carboxylic acids, such as oleic acid and the like, alicyclic carboxylic acids such as naphthenic acid and aryl carboxylic acids, such as benzoic acid.
  • the metal may be selected from the group consisting of sodium, potassium, iron, magnesium, calcium, zinc, barium, aluminum, tin, zirconium, lithium, cadmium, and cobalt.
  • Zinc is preferred.
  • a particularly preferred monomer for this use is zinc dimethacrylate, which may also be referred to as a metal salt. Suitable zinc salts of acrylic acid are described in Sartomer Co., Inc., "New Metallic Coagents for Curing Elastomers", April 1998.
  • the metal salt of the carboxylic acid is present in an amount from 5 to 90 parts by weight per hundred parts by weight of rubber. In a more preferred embodiment of the invention, the metal salt is present in an amount from 10 to 60 parts by weight per hundred parts by weight of rubber. In a most preferred embodiment of the invention, the metal salt is present in an amount from 20 to 50 parts by weight per hundred parts by weight of rubber.
  • Zinc dimethacrylate or other metal salt of a carboxylic acid is combined with at least one of the rubber polymers disclosed above in a grafting reaction such that the polymer of the metal salt is grafted onto the polymeric backbone.
  • Zinc dimethacrylate may be prepared by reacting with agitation zinc oxide and methacrylic acid in an amount of from about 0.5 to about 0.6 moles of zinc oxide per mole of methacrylic acid in a liquid medium (e.g. water or a volatile organic liquid such as a liquid hydrocarbon).
  • the present inventors have found that the two inserts, though made with different curing systems, do not separate from one another during operation of the vehicle in the flat-tire mode. Furthermore, the second insert, cured with the metal salt/acrylic acid/peroxide system, has higher thermal stability, permitting longer operation of the tire in the uninflated condition. It has been found that more than two inserts can be used, but at least two inserts, as defined herein, work well.
  • a series of three or more adjacent inserts provides support for each of the sidewalls, the adjacent inserts having a gradient of elasticity. The insert having the lower modulus of elasticity would be next to the sidewall, with the modulus of elasticity increasing from that point toward the interior of the tire.
  • the inserts are crescent-shaped.
  • this support system contributes relatively negligible mass, rolling resistance, and stiffness (which affects comfort) to the tire.
  • this support system In the deflated mode, this support system exhibits high stiffness, low hysteresis, thermomechanical stability (at dynamic strain levels of greater than 10%), and enhanced thermo-oxidative stability.
  • Figure 1 shows one embodiment of the present invention. Runflat tire 1 is shown in partial section having a rim contacting bead area 10, sidewall section 30, and crown tread 3.
  • the bead area 10 includes bead wire 12, bead core 43 that anchors carcass-reinforcing ply 42.
  • Underlying the tread 3 is the belt package 50 comprising reinforcing plies.
  • inserts 22 and 24 are elastomeric, and in one embodiment the elastomer is a rubber compound. In one embodiment of the invention, each of inserts 22 and 24 have a major concave surface and a major convex surface.
  • the convex surface of insert 22 lies adjacent to the concave surface of insert 24.
  • First insert 24 is nearer the sidewall than second insert 22.
  • Inserts 22 and 24 are radially adjacent to one another.
  • elastomeric crescent-shaped second insert 22 in the sidewall is compounded to have a peroxide and co-agent cured system.
  • the rubber employed in insert 22 may be a natural rubber or a synthetic rubber that is curable with a metal salt of a carboxylic acid and a peroxide cure system. Blends of such rubbers may also be employed.
  • Such rubbers include, but are not limited to: Olefinic thermoplastic elastomer; polybutadiene thermoplastic elastomer, e.g., syndiotactic 1 ,2-polybutadiene thermoplastic elastomer; polyester thermoplastic elastomer; polyurethane thermoplastic elastomer, for example, thermoplastic polyester-polyurethane elastomer, and thermoplastic polyether-polyurethane elastomer; styrenic thermoplastic elastomer.
  • Olefinic thermoplastic elastomer polybutadiene thermoplastic elastomer, e.g., syndiotactic 1 ,2-polybutadiene thermoplastic elastomer
  • polyester thermoplastic elastomer polyester thermoplastic elastomer
  • polyurethane thermoplastic elastomer for example, thermoplastic polyester-polyurethane elastomer, and thermoplastic polyether-polyurethane
  • rubbery polymers may also be employed, including acrylic rubber, such as ethylene-acrylate copolymer; and butadiene rubber, such as polybutadiene.
  • Butyl-containing polymers useful for this invention include, without limitation: bromobutyl rubber, e.g., bromoisobutylene-isoprene copolymer; poly(isobutylene-co-acrylonitrile) and poly(isobutylene-co- paramethylstyrene) may also be employed.
  • bromobutyl rubber e.g., bromoisobutylene-isoprene copolymer
  • poly(isobutylene-co-acrylonitrile) and poly(isobutylene-co- paramethylstyrene) may also be employed.
  • Other butyl-containing polymers may be readily selected by one of skill in the art.
  • Useful elastomeric polymers also include chlorosulfonated polyethylene rubber, e.g., chlorosulfonated polyethylene; ethylene-propylene rubber, such as ethylene-propylene copolymer, and ethylene-propylene-diene copolymer (EPDM).
  • chlorosulfonated polyethylene rubber e.g., chlorosulfonated polyethylene
  • ethylene-propylene rubber such as ethylene-propylene copolymer, and ethylene-propylene-diene copolymer (EPDM).
  • EPDM ethylene-propylene-diene copolymer
  • elastomeric polymers include neoprene rubber such as polychloroprene; nitrile rubber, such as acrylonitrile-butadiene copolymer; polyisoprene rubber; polysulfide rubber; propylene oxide rubber; silicone rubber, such as silicone (MQ), and styrene-butadiene rubber, such as styrene- butadiene copolymer (SBR).
  • neoprene rubber such as polychloroprene
  • nitrile rubber such as acrylonitrile-butadiene copolymer
  • polyisoprene rubber such as acrylonitrile-butadiene copolymer
  • polysulfide rubber polysulfide rubber
  • propylene oxide rubber silicone rubber, such as silicone (MQ)
  • silicone rubber such as silicone (MQ)
  • SBR styrene-butadiene rubber
  • Preferred rubbers include natural rubber, polyisoprene, polybutadiene, acrylonitrile butadiene rubber, ethylene-propylene diene rubber, styrene butadiene rubber, brominated isobutylene-isoprene rubber, and brominated isobutylene-paramethyl styrene rubber.
  • rubber and “elastomer” are synonymous.
  • Peroxides which may be employed to catalyze the curing of the elastomer of crescent-shaped insert 22 include, but are not limited to: di-cumyl peroxide, bis-(tert-butyl peroxy)-diisopropyl benzene, t-butyl perbenzoate, di- tert-butyl peroxide, 2,5-dimethyl-2,5-di-tert-butylperoxide hexane, etc.
  • Amounts of peroxide curing agents included in the composition will depend upon the elastomer and coagent loading utilized. In general, such amounts may range from about 0.5 parts per hundred weight to about 5.0 parts per hundred weight of elastomer.
  • Zinc dimethyl methacrylate may be formed from the combination of zinc oxide and methacrylic acid.
  • insert (22) is composed of a blend of natural rubber and polybutadiene ranging from 100% (by weight) natural rubber to 20% natural rubber/80% polybutadiene (by weight). Insert (22) also may contain carbon black (up to 120 parts per hundred weight of elastomer) and/or precipitated silica (up to 90 parts per hundred weight of elastomer).
  • insert 22 has a shore A hardness greater than 74, and preferably greater than 80, while insert 24 has a shore A hardness greater than 90 or 95.
  • insert 22 has an elastic modulus greater than 35 or 40 kg/(cm squared) when the elongation strain is 100 percent, and insert 22 has an elastic modulus greater than 65 or 70 kg/(cm squared) when the elongation strain is 100 percent.
  • the remaining portions of the tire include rubber components with conventional sulfur-accelerated vulcanization systems to obtain multiple carbon-sulfur and sulfur-sulfur links.
  • Elastomers which may be employed to form crescent-shaped insert 24 include, but are not limited to those elastomers listed above for insert 22.
  • crescent-shaped insert 22 have a modulus of elasticity of between 10 — 50 MPa at 10% elongation, while crescent-shaped insert 24 has a modulus of elasticity of between 5-15 MPa at 10% elongation.
  • One embodiment of the invention is a pneumatic tire having enhanced physical properties and run-flat endurance, where at least one reinforced radial carcass layer has a crown portion and a pair of end portions each anchored in a respective spaced apart bead; a tread outward of said crown portion of said carcass layer and a reinforced belt portion between said tread and said carcass layer; a pair of sidewall inserts each adjacent said carcass layer and extending radially from a respective bead to a respective lateral edge of said tread; and there is an innerliner interior to said carcass layer to retain air inside a cavity of the tire.
  • the improvement in this tire is in that each one of said pair of sidewalls has inserts for providing continuous running with the loss of inflation pressure.
  • the pair of sidewalls each includes a first insert inserted to the interior of said at least one carcass layer, the first insert comprising rubber having a sulfur-accelerated system for curing.
  • the second insert is inserted to the interior of the first insert, and has a common interface with the first insert.
  • the second insert comprises rubber and has a peroxide and a co-agent for curing.
  • the second insert has a higher modulus of elasticity than the first insert.
  • the co-agent comprises a metal salt of a carboxylic acid.
  • the metal salt may comprise a metal selected from the group consisting of sodium, potassium, iron, magnesium, calcium, zinc, barium, aluminum, tin, zirconium, lithium, cadmium, and cobalt and mixtures thereof.
  • the carboxylic acid is selected from saturated and unsaturated carboxylic acids and mixtures thereof.
  • the carboxylic acids are selected from the group consisting of methacrylic acid, ethacrylic acid, acrylic acid, cinnamic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, acetic acid, butyric acid, lauric acid, palmitic acid, stearic acid, naphthenic acid, and benzoic acid and mixtures thereof.
  • the peroxide may be selected from the group consisting of di-cumyl peroxide, bis-(tert-butyl peroxy)-diisopropyl benzene, t-butyl perbenzoate, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di-tert-butylperoxide hexane and mixtures thereof.
  • the metal salt of the carboxylic acid is preferably zinc dimethacrylate.
  • the first insert has modulus of elasticity at ten percent unit strain in a range of about 5 mega Pascals to about 15 mega Pascals and the second insert has a modulus of elasticity at ten percent unit strain in a range of about 10 mega Pascals to about 50 mega Pascals.
  • Another embodiment of the invention is a pneumatic tire, the improvement comprising multiple sidewall stiffening inserts, where:
  • a first stiffening insert comprises a sulfur-curable rubber composition
  • a second stiffening insert comprises a peroxide-curable rubber composition; and the first and second inserts are adjacent each other and in contact along a common interface.
  • the first insert may be crescent-shaped. It may comprise a mixture of rubber, a metal salt of an acrylic acid, and a peroxide curing agent.
  • the rubber is selected from the group consisting of natural rubbers and synthetic rubbers. In one embodiment of the invention, the rubber is selected from the group consisting of natural rubber, alkadienic rubbers, silicone rubbers, polyurethane rubbers, polyester thermoplastic elastomer, acrylic rubber, nitrile rubber, neoprene rubber, polyisoprene rubber, and styrene-butadiene rubber and mixtures thereof.
  • the insert comprises a rubber selected from the group consisting of natural rubber, polyisoprene, polybutadiene, acrylonitrile butadiene rubber, ethylene-propylene diene rubber, styrene butadiene rubber, isobutylene-isoprene, styrenic thermoplastic elastomer, ethylene-acrylate copolymer; bromobutyl rubber, bromoisobutylene- isoprene copolymer, poly(isobutylene-co-acrylonitrile) and poly(isobutylene-co- paramethylstyrene), chlorosulfonated polyethylene; ethylene-propylene copolymer, ethylene-propylene-diene copolymer, polychloroprene, acrylonitrile- butadiene copolymer, polysulfide rubber; propylene oxide rubber, brominated isobutylene-isoprene rubber, and bro
  • the metal salt carboxylate is selected from the group consisting of zinc diacrylate and zinc di-methacrylate.
  • the second insert comprises 5 to 90 parts of metal salt of a carboxylic acid per hundred parts by weight of rubber.
  • the first insert comprises 10 to 60 parts of metal salt of a carboxylic acid per hundred parts by weight of rubber.
  • the first insert comprises 20 to 50 parts of metal salt of a carboxylic acid per hundred parts by weight of rubber.
  • a tire according to the invention may be, for example, a bias-ply tire or a radial tire.
  • an insert is comprised of a blend of natural rubber and polybutadiene wherein the polybutadiene ranges from zero percent by weight to eighty percent by weight, and the natural rubber ranges from one hundred percent by weight to twenty percent by weight.
  • the inserts may further comprise a filler such as carbon black and silica.
  • the filler comprises 0 to 120 parts by weight per hundred parts rubber.
  • the filler comprises 0 to 65 parts by weight per hundred weight of rubber.
  • the inserts may also be crescent shaped.
  • a tire comprises a sidewall, where the sidewall includes at least two adjacent crescent-shaped inserts.
  • Each insert has a major concave surface and a major convex surface, where the major concave surface of the first insert lies adjacent to the major convex surface of the second insert, and the first insert is substantially nearer the sidewall than the second insert.
  • the second insert comprises a peroxide- curable rubber composition including a metal salt of a carboxylic acid
  • the first insert comprises a sulphur-curable rubber composition.
  • the metal salt of the carboxylic acid is selected from zinc diacrylate and zinc dimethacrylate.
  • a tire in another embodiment, comprises a sidewall, where the sidewall includes at least two radially adjacent crescent-shaped inserts, wherein said radius is drawn from the centerpoint of the tire.
  • the first insert is substantially nearer the sidewall than the first insert
  • the second insert comprises a peroxide-curable rubber composition including a metal salt of a carboxylic acid, and wherein said first insert comprises a sulphur-curable rubber composition.
  • the first insert has a shore A hardness greater than 72, and an elastic modulus greater than 35 kg/cm 2 when the elongation strain is one hundred percent, and wherein the second insert has a shore A hardness greater than 90, and an elastic modulus greater than 65 kg/cm 2 when the elongation strain is one hundred percent.
  • the first insert has a shore A hardness greater than 75, and an elastic modulus greater than 40 kg/cm 2 when the elongation strain is one hundred percent, and wherein the second insert has a shore A hardness greater than 95, and an elastic modulus greater than 70 kg/cm 2 when the elongation strain is one hundred percent.
  • the second insert comprises 20 to
  • the second insert further comprises a filler comprising 0 to 120 parts by weight per hundred parts rubber. In another embodiment of the invention, the second insert further comprises a filler comprising 0 to 65 parts by weight per hundred parts rubber.
  • the second insert further comprises between 0 and 2.5 parts by weight sulfur per hundred parts by weight of rubber.
  • the rubber mix of crescent-shaped insert 22 was created by replacing the sulfur vulcanization system of the conventional sulfur-cured crescent-shaped insert 24 with dicumyl peroxide and portions of the carbon black with zinc dimethacrylate (ZDMA).
  • compositions are shown in greater detail in Table 1. The proportions are given in parts per hundred weight of rubber.
  • [6PPD is N- (1, 3-dimethylbutyl) -N' -phenyl-p-phenylenediamine .
  • TMQ is poly (1, 2-dihydro-2, 2, 4-trimethyl quinoline. It is also known and Vulcanox 4020, by Bayer]
  • the force divided by the original area of the sample under duress is called the stress (shown above in units of mega Pascals).
  • the displacement (movement or stretch) of the material is called the strain.
  • the strain Normally the strain is given as the change in length divided by the original length, and the units are dimensionless.
  • the modulus is the slope of the curve of stress versus strain (stress in the ordinate, strain in the abscissa).
  • the elastic shear modulus (G') of a material is the ratio of the elastic (in-phase) stress to strain and relates to the ability of a material to store energy elastically.
  • the loss modulus (G) of a material is the ratio of the viscous (out of phase) component to the shear strain, and is related to the material's ability to dissipate stress through heat.
  • the ratio of these moduli (G7G") is defined as tangent delta, and indicates the relative degree of viscous to elastic dissipation, or damping of the material.
  • a low tan delta means higher resilience and less hysteresis.
  • G' represents the shear modulus in mega Pascals
  • tan delta represents the relative hysteresis of the material.
  • the first insert 24 was formed from a control mixture with a sulfur curing system [a different control than that of Table 1].
  • the second insert 22 was formed from a peroxide co-agent curing system.
  • Crescent-shaped inserts were formed with this composition having the respective general cross-sections shown in Figure 1. These inserts were positioned in a conventional mold after the other tire components were arranged. After the inner liner was put into place, the mold closed and heating began according to a predetermined schedule. Curing was terminated after the first insert was essentially cured. The tire of this invention was cured in a single curing operation. This did not degrade the endurance of the tire, but surprisingly enhanced the endurance of the tire (see below).
  • a tire with inserts compounded as above was compared with experimental control tires of the same size and architecture.
  • the standard Tire and Rim Association (Copley, Ohio 44321) dimensions were 205/50 R17; with the tires having an architecture of the Michelin MXM4 ZP tire line (Michelin North America, Inc. Greenville, SC). These tires are illustrated in Fig. 1.
  • Various tire and material performance parameters were measured to compare the experimental control tires with the tire of this invention.
  • the control tires were made with the same components except the second crescent-shaped insert 22 was made with the same first compound as the first crescent shaped insert 24, being a sulfur-accelerated system. Two tires of each type were tested. The tires were heated to a temperature of 160 degrees centigrade before terminating the cure at 17 minutes.
  • the integrity of the cured tire of this invention was investigated by measuring Shore A hardness and modulus of elasticity (modulus) of the first and second crescent shaped inserts.
  • the modulus at ten percent unit strain for the first crescent shaped insert 24 was nine (9) mega Pascals (MPa) and the modulus for second crescent shaped insert 22 was seventeen (17) MPa.
  • the curing time to reach a given percent vulcanization for the peroxide co-agent cured system is longer than that of the sulfur-cured system to reach the same percent vulcanization, the strength of the peroxide co-agent cured system is realized by terminating the cure based on the cure law of the sulfur cured system. This is at least partially due to the location of second crescent-shaped insert 22 adjacent to the innerliner 26 to provide a higher level of input thermal energy during curing of the tire.
  • the Shore A hardness across the first crescent-shaped insert was constant at 74 and the Shore A hardness across the second crescent shaped insert was constant at 90. There was no point where the hardness at the interface 23 dropped below that of either crescent-shaped insert. Therefore, the degrading of the physical properties of either crescent-shaped insert by the other adjacent crescent-shaped insert which might be expected because of the proximity of the antioxidant (6PPD), sulphur and peroxide curing systems was not found. That is, a weakening or separation at the interface 23 between the crescent-shaped inserts did not occur.
  • An important physical parameter of a run-flat tire is the amount of deflection under load with zero inflation pressure.
  • the amount of deflection directly relates to the amount of strain the various tire components are subjected to with each rotation of the tire. Durability of the tire is greatly improved with small decreases in deflection of the loaded tire.
  • the tire of this invention had a deflection of 25.9 millimeters under a load of 490 kilograms compared with an average of 28.1 millimeters for the control tires under the same load. This is an eight (8) percent reduction in the deflection.
  • the radial stiffness of the tire was improved by 8.5 percent, as measured by vertical deflection on an STL machine. This reduction is a direct result of the higher modulus of the second crescent shaped insert, which results in less strain in the tire's components and the interfaces between components.
  • Tire endurance for a run-flat tire is best measured by recording the number of miles traveled by a vehicle at a given speed, with zero pressure in the tires, without the tire being physically impaired.
  • Typical failure modes for a pneumatic tire include cracking of the sidewall, and under high heat conditions, softening of the tire material.
  • the run-flat tires of this invention were placed on a Bayerische Motor Werke (BMW) vehicle. One tire lasted for 173 miles until the car was stopped by the driver. Inspection of the tire showed some cracking in the support. The other tire went 200 miles, at which time the test was stopped and an inspection of the tire showed no evidence of extensive physical damage to the support system of the tires.
  • the test run was performed at a variety of speeds not exceeding 55 miles per hour, on a winding test track that gave high lateral force loading. No failures were present at interface 23 between the first and second crescent shaped inserts for the tire of this invention.
  • the higher modulus of elasticity of the innermost crescent-shaped insert allowed the runflat tire of this invention to operate with less deflection when running without an inflation pressure. Less deflection reduced the unit strains within the runflat tire, thereby decreasing heat build-up. Higher modulus also improved the handling of the tire in the zero inflation condition.
  • the greater thermal stability of the elastomer cured with peroxides and the metal salt of an acrylic acid meant that longer operation of the tire was possible in the uninflated state before the support system broke down. It is therefore expected that a tire according to the present invention will be able to travel over 200 miles in the uninflated condition without breaking down.

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  • Mechanical Engineering (AREA)
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  • Organic Chemistry (AREA)
  • Tires In General (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

La présente invention concerne un pneu avec un système de maintien comprenant deux inclusions adjacentes en croissant à l'intérieur du flanc. Lorsque le pneu perd de la pression de gonflage, éventuellement due à une crevaison soudaine, l'inclusion assure un maintien suffisant du pneu pour permettre la poursuite d'un fonctionnement normal et confortable de l'automobile jusqu'à ce que le pneu puisse être réparé ou remplacé. La première inclusion en croissant (24), celle qui est la plus proche du flanc extérieur, présente un module élastique plus bas, et donc moins de rigidité, que la deuxième inclusion en croissant (22). La première inclusion (24) est faire d'un élastomère, c'est à dire d'une gomme, vulcanisée avec un système soufré, alors que la deuxième inclusion (22) est faite d'un élastomère vulcanisé avec un catalyseur peroxydé et un sel de métal d'un acide carboxylique, notamment le diméthacrylate de zinc.
PCT/US2001/017257 2001-05-29 2001-05-29 Pneu pouvant rouler a plat WO2002096677A1 (fr)

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PCT/US2001/017257 WO2002096677A1 (fr) 2001-05-29 2001-05-29 Pneu pouvant rouler a plat
PCT/US2002/017174 WO2002096672A2 (fr) 2001-05-29 2002-05-29 Pneu a affaissement limite
AU2002316181A AU2002316181A1 (en) 2001-05-29 2002-05-29 Runflat tire

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US8546464B2 (en) 2008-06-26 2013-10-01 Bridgestone Corporation Rubber compositions including metal-functionalized polyisobutylene derivatives and methods for preparing such compositions
WO2014057082A1 (fr) 2012-10-12 2014-04-17 Compagnie Generale Des Etablissements Michelin Pneumatique adapté pour un roulage à plat comprenant nappe de carcasse hybride
US8802755B2 (en) 2011-01-18 2014-08-12 Bridgestone Corporation Rubber compositions including metal phosphate esters
US8901217B2 (en) 2009-07-01 2014-12-02 Bridgestone Corporation Multiple-acid-derived metal soaps incorporated in rubber compositions and method for incorporating such soaps in rubber compositions
US9090127B2 (en) * 2007-12-31 2015-07-28 Bridgestone Corporation Metal soaps incorporated in rubber compositions and method for incorporating such soaps in rubber compositions
WO2016156263A1 (fr) 2015-03-31 2016-10-06 Compagnie Generale Des Etablissements Michelin Elément de renfort hybride à torsions différenciées
US9670341B2 (en) 2012-11-02 2017-06-06 Bridgestone Corporation Rubber compositions comprising metal carboxylates and processes for making the same
US9803060B2 (en) 2009-09-10 2017-10-31 Bridgestone Corporation Compositions and method for making hollow nanoparticles from metal soaps
WO2018051032A1 (fr) 2016-09-19 2018-03-22 Compagnie Generale Des Etablissements Michelin Élément de renfort, composite d'élastomère et pneumatique comprenant cet élément de renfort
WO2018051031A1 (fr) 2016-09-19 2018-03-22 Compagnie Generale Des Etablissements Michelin Composite d'élastomère et pneumatique comprenant ce composite
WO2018162854A1 (fr) * 2017-03-08 2018-09-13 Compagnie Generale Des Etablissements Michelin Pneumatique muni d'une composition comprenant un elastomere riche en ethylene, un peroxyde et un acrylate de zinc
CN108859616A (zh) * 2018-07-12 2018-11-23 万力轮胎股份有限公司 一种缺气保用轮胎
US10752806B2 (en) 2014-06-18 2020-08-25 Ppg Industries Ohio, Inc. Elastic gas barrier coating compositions
US11286369B2 (en) 2017-03-08 2022-03-29 Compagnie Generale Des Etablissements Michelin Tire having a composition comprising an ethylene-rich elastomer, a peroxide and a polyfunctional acrylate derivative

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WO2006071228A1 (fr) * 2004-12-29 2006-07-06 Michelin Recherche Et Technique S.A. Pneumatique a mobilite accrue presentant une configuration asymetrique de materiaux entre les carcasses
KR20080031846A (ko) * 2005-06-27 2008-04-11 도오레 화인케미칼 가부시키가이샤 경화형 조성물
DE102008014986A1 (de) 2008-03-19 2009-09-24 Continental Aktiengesellschaft Fahrzeugluftreifen mit Notlaufeigenschaften und Verfahren zu seiner Herstellung
EP3138700B1 (fr) * 2014-04-28 2019-10-23 Sumitomo Rubber Industries, Ltd. Pneumatique
JP5932882B2 (ja) * 2014-05-14 2016-06-08 住友ゴム工業株式会社 空気入りタイヤ
WO2019086785A1 (fr) * 2017-10-31 2019-05-09 Compagnie Generale Des Etablissements Michelin Pneumatique a flancs autoporteurs optimise
CN118006051A (zh) * 2024-04-08 2024-05-10 寿光福麦斯轮胎有限公司 一种轮胎气密层用橡胶组合物及其制备方法

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US4713409A (en) * 1982-09-21 1987-12-15 The Firestone Tire & Rubber Company Vulcanizable polymeric compositions containing a zinc dimethacrylate adjuvant and method for preparing the adjuvant
US4917164A (en) * 1986-04-30 1990-04-17 Bridgestone Corporation Pneumatic safety tire
US4931508A (en) * 1988-05-13 1990-06-05 Servus Rubber Company, Inc. Co-curing of NR/EPDM rubber blends
US5217807A (en) * 1989-01-17 1993-06-08 Uniroyal Chemical Company, Inc. Metal acrylates as rubber-to-metal adhesion promoters
US5309970A (en) * 1991-05-22 1994-05-10 Bridgestone Corporation Pneumatic safety tires
US5494091A (en) * 1992-12-30 1996-02-27 Bridgestone Corporation High modulus low hysteresis rubber compound for pneumatic tires
US5310811A (en) * 1993-09-22 1994-05-10 The Goodyear Tire & Rubber Company Free radical cured rubber employing acrylate or methacrylate esters of hydroxybenzene and hydroxynaphthalene compounds as co-curing agents
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Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9090127B2 (en) * 2007-12-31 2015-07-28 Bridgestone Corporation Metal soaps incorporated in rubber compositions and method for incorporating such soaps in rubber compositions
US9637613B2 (en) 2007-12-31 2017-05-02 Bridgestone Corporation Metal soaps incorporated in rubber compositions and method for incorporating such soaps in rubber compositions
US8546464B2 (en) 2008-06-26 2013-10-01 Bridgestone Corporation Rubber compositions including metal-functionalized polyisobutylene derivatives and methods for preparing such compositions
US8901217B2 (en) 2009-07-01 2014-12-02 Bridgestone Corporation Multiple-acid-derived metal soaps incorporated in rubber compositions and method for incorporating such soaps in rubber compositions
US9803060B2 (en) 2009-09-10 2017-10-31 Bridgestone Corporation Compositions and method for making hollow nanoparticles from metal soaps
US8802755B2 (en) 2011-01-18 2014-08-12 Bridgestone Corporation Rubber compositions including metal phosphate esters
WO2014057082A1 (fr) 2012-10-12 2014-04-17 Compagnie Generale Des Etablissements Michelin Pneumatique adapté pour un roulage à plat comprenant nappe de carcasse hybride
US9670341B2 (en) 2012-11-02 2017-06-06 Bridgestone Corporation Rubber compositions comprising metal carboxylates and processes for making the same
US10752806B2 (en) 2014-06-18 2020-08-25 Ppg Industries Ohio, Inc. Elastic gas barrier coating compositions
WO2016156263A1 (fr) 2015-03-31 2016-10-06 Compagnie Generale Des Etablissements Michelin Elément de renfort hybride à torsions différenciées
WO2018051032A1 (fr) 2016-09-19 2018-03-22 Compagnie Generale Des Etablissements Michelin Élément de renfort, composite d'élastomère et pneumatique comprenant cet élément de renfort
WO2018051031A1 (fr) 2016-09-19 2018-03-22 Compagnie Generale Des Etablissements Michelin Composite d'élastomère et pneumatique comprenant ce composite
WO2018162854A1 (fr) * 2017-03-08 2018-09-13 Compagnie Generale Des Etablissements Michelin Pneumatique muni d'une composition comprenant un elastomere riche en ethylene, un peroxyde et un acrylate de zinc
CN110382610A (zh) * 2017-03-08 2019-10-25 米其林集团总公司 具有包括富乙烯弹性体，过氧化物和丙烯酸锌的组合物的轮胎
FR3063731A1 (fr) * 2017-03-08 2018-09-14 Compagnie Generale Des Etablissements Michelin Pneumatique muni d'une composition comprenant un elastomere riche en ethylene, un peroxyde et un acrylate de zinc
CN110382610B (zh) * 2017-03-08 2021-10-22 米其林集团总公司 具有包括富乙烯弹性体，过氧化物和丙烯酸锌的组合物的轮胎
US11254804B2 (en) 2017-03-08 2022-02-22 Compagnie Generale Des Etablissements Michelin Tire having a composition comprising an ethylene-rich elastomer, a peroxide and a zinc acrylate
US11286369B2 (en) 2017-03-08 2022-03-29 Compagnie Generale Des Etablissements Michelin Tire having a composition comprising an ethylene-rich elastomer, a peroxide and a polyfunctional acrylate derivative
CN108859616A (zh) * 2018-07-12 2018-11-23 万力轮胎股份有限公司 一种缺气保用轮胎

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WO2002096672A3 (fr) 2007-11-15
WO2002096672A2 (fr) 2002-12-05
AU2002316181A1 (en) 2002-12-09

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