JP2004291725A - Run flat tire supporting element, manufacturing method thereof, and run flat tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a run flat tire supporting element having more lightweight, made of a closed-celled foam element having small bubbles, and preventing shape deformation due to time duration, and also to provide a manufacturing method thereof, and a run flat tire. <P>SOLUTION: A ring-shaped core type run flat tire supporting element is made of a polyurethane foam elastic element and attached to a rim. The polyurethane foam elastic element is a foam element formed by a closed cell made by filling non-reactive gas in bubbles having an average bubble diameter of 20 to 200 μm. The run flat tire supporting element has: a bubble dispersion manufacturing step adding silicon surfactant to isocyanate base terminal prepolymer, and agitating and mixing that with the non-reactive gas to make bubble dispersion; a mixing step mixing active hydrogen group-containing compound into the bubble dispersion to be a reactive composition; and a molding step injecting the reactive composition into a mold and reactively curing that to be the polyurethane foam elastic element. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

以上の結果より、本発明のランフラットタイヤ用支持体は、従来のポリウレタン製支持体と比較してより軽量であり、気泡が小さく独立気泡の発泡体からなるものであることが分かる。また、気泡を構成する気体は空気であり、時間経過による形状安定性にも優れたものであった。
【図面の簡単な説明】
【図１】ランフラットタイヤの内部構造を例示した斜視図
【図２】ランフラットタイヤの構造を示した断面図
【図３】凹部を有するランフラットタイヤ支持体の別の実施形態を例示した斜視図
【図４】凹部を有するランフラットタイヤ支持体の断面図
【図５】支持体に形成された凹部の配置を例示した部分側面図とこれに対応する上面図[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a support for a run-flat tire that is mounted on a rim of an automobile tire, is disposed inside a pneumatic tire, maintains a necessary tire outer diameter when the tire is punctured, and can run safely. The present invention relates to a production method thereof and a run flat tire using the support.
[0002]
[Prior art]
Runflat tires can withstand the load and running of a vehicle until it reaches the nearest service facility, even if the tire pressure drops significantly or becomes zero due to a puncture or other cause. It is a tire with durability. As the run flat tire, a side reinforcement type in which the side portion of the tire is reinforced and a core type in which a support (core) is housed inside the tire are in practical use.
[0003]
As a core type run flat tire support, a non-foamed support using a polyurethane elastomer having a tensile modulus at 80 ° C. of 20 to 60 MPa is known (Patent Document 1).
[0004]
Also, a run flat tire in which the tire internal space is filled with a foam such as polyurethane foam is known (Patent Document 2).
[0005]
[Patent Document 1]
WO 01 / 42000A1 [Patent Document 2]
GB A 2013143 gazette [Problems to be solved by the invention]
However, although the support using the polyurethane elastomer disclosed in Patent Document 1 is sufficient in safety, there is a limit in reducing the weight of the support, and the fuel consumption due to the weight reduction of the entire vehicle is limited. The demand for reduction cannot be sufficiently met.
[0006]
Further, in the run flat tire described in Patent Literature 2, a support inside the tire is formed of a polyurethane foam. A flexible polyurethane foam needs to be a closed-cell foam in consideration of the load-bearing capacity.However, when a low-boiling organic compound is used as a foaming agent, the foaming agent is liquefied after molding, and thus the foam is foamed. The molded body shrinks due to a decrease in internal pressure, and the shape stability is not sufficient. When water is used as a foaming agent to form a closed-cell foam, the foaming gas that forms the bubbles is a carbon dioxide gas formed by the reaction of the isocyanate groups and water, and the permeability of the polyurethane cell wall is low. Since it is higher than air, there is a problem in that the carbon dioxide gas in the cells loses permeation over time, the foam shrinks, and the shape of the molded body also changes.
[0007]
An object of the present invention is to provide a support for a run-flat tire, which is lighter and is made of a foam of closed cells in which bubbles are small and does not cause a shape change with time, a method for manufacturing the same, and a lighter weight and shape with time. It is to provide a run-flat tire that does not change.
[0008]
[Means for Solving the Problems]
The present invention is a ring-shaped core-type run flat tire support composed of a polyurethane foam elastic body and mounted on a rim,
The polyurethane foam elastic body is a foam formed of fine closed cells in which non-reactive gas is filled in cells having an average cell diameter of 20 to 200 μm.
[0009]
The run flat tire support having such a configuration is made of a closed-cell foam having lighter weight and small cells while having necessary mechanical strength and the like, in particular, compressive strength. The non-reactive gas is preferably air or nitrogen, and due to such a configuration, water is used as a foaming agent, and unlike polyurethane foam in which carbon dioxide gas is filled in bubbles, bubbles due to gas permeation loss in bubbles are reduced. Since no shrinkage occurs, a support having excellent shape stability over time is formed.
[0010]
If the average cell diameter exceeds 200 μm, the rate of air void generation increases, and the compressive strength also decreases. It is difficult to manufacture a lightweight polyurethane foam elastic body having an average cell diameter of 20 μm or less. The average cell diameter of the polyurethane foam elastic body constituting the run flat tire support is more preferably 30 to 100 μm.
[0011]
Polyurethane foam elastic body constituting the run-flat tire support is preferably a density of 0.3~0.8kg / ^{m 3.}
[0012]
A polyurethane foam elastic body composed of closed cells having an average cell diameter of 20 to 200 μm and having a density in the above range has sufficient mechanical strength, particularly compressive strength, and forms a lighter support.
[0013]
If the density is less than 0.3 kg / ^{m 3,} there is a case where mechanical strength is lowered, weight reduction effect is not sufficient and when it exceeds 0.8 kg / ^{m 3.}
[0014]
The density of the polyurethane foam elastic body is more preferably from 0.4 to 0.7 kg / m ³ , because the balance between strength and weight reduction is excellent.
[0015]
It is preferable that the compression elastic modulus at the time of 5% deformation of the polyurethane foam elastic body constituting the run flat tire support of the present invention is 0.3 to 3 MPa.
[0016]
When the elastic modulus of the polyurethane foam is less than 0.3 MPa at the time of 5% deformation, the load resistance during run-flat running is not sufficient, and when it exceeds 3 MPa, it becomes too hard to be mounted on a tire. In addition, there is a problem that vibration during traveling increases.
[0017]
Another invention is a method for producing a ring-shaped run flat tire support, which is made of a polyurethane foam elastic body and is attached to a rim,
A bubble dispersion liquid in which a silicon-based surfactant is added to an isocyanate group-terminated prepolymer, and the resulting mixture is stirred and mixed with a non-reactive gas to disperse the non-reactive gas as fine bubbles in the isocyanate group-terminated prepolymer to form a bubble dispersion A manufacturing step, a mixing step of mixing an active hydrogen group-containing compound with the foam dispersion to form a reactive composition, and a polyurethane having fine closed cells by injecting the reactive composition into a mold and reaction-curing the mixture. It is characterized by having a molding step of forming a foam elastic body.
[0018]
According to the manufacturing method having such a configuration, it is possible to manufacture a foam formed of fine closed cells filled with a non-reactive gas, preferably air or nitrogen, in cells having an average cell diameter of 20 to 200 μm.
[0019]
By adding a silicon surfactant to the isocyanate group-containing prepolymer and agitating it vigorously in the presence of a non-reactive gas, these liquids become bubble dispersion liquids containing fine non-reactive gas bubbles. Then, an active hydrogen group-containing compound as a reaction partner is added to obtain a reactive composition, and a polymerization reaction is carried out to obtain a polyurethane foam having a uniform fine closed cell structure.
[0020]
The average cell diameter of the polyurethane foam elastic body is preferably 20 to 200 μm.
[0021]
Density of the polyurethane foam elastic body is preferably 0.3 to 0.8 g / cm ^3, more preferably 0.4 to 0.7 g / cm ^3.
[0022]
Another aspect of the present invention is a run flat tire, wherein the run flat tire support according to claim 1 or 2 is used.
[0023]
Still another aspect of the present invention provides a run-flat tire using a support manufactured by the manufacturing method according to any one of claims 3 to 5.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
The isocyanate group-terminated prepolymer and the active hydrogen group-containing compound are used for the polyurethane foam elastic material constituting the support for the run flat tire of the present invention. The isocyanate group-terminated prepolymer is obtained by reacting a polyol compound and a diisocyanate compound at a ratio where the equivalent of the isocyanate group is in excess of the equivalent of the hydroxyl group, preferably at an NCO / OH equivalent ratio of 1.7 to 2.5. Can be Unreacted diisocyanate compounds may coexist. The use of a commercially available isocyanate group-terminated prepolymer is also suitable, and for example, adiprene L-100, L-167 (manufactured by Uniroyal) is exemplified as a suitable material.
[0025]
Specific examples of the diisocyanate compound usable in the present invention include 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, naphthalene diisocyanate, Aromatic diisocyanate compounds such as 2,4-phenylenediisocyanate, aliphatic diisocyanates such as 2,2,4-trimethylhexamethylene diisocyanate and 1,6-hexamethylene diisocyanate (HDI), and hydrogenated 4,4'-diphenylmethane diisocyanate ( HMDI), 1,4-cyclohexane diisocyanate (CHDI), isophorone diisocyanate (IPDI), alicyclic diisocyanates, xylylene diisocyanate, and the like. That.
[0026]
The polyol compound is an oligomer having a molecular weight of about 500 to 10,000 based on a terminal group determination method, and specifically includes, for example, polyether polyol, polyester polyol, polybutadiene polyol, polyisoprene polyol, polyester-polyether polyol, and polycarbonate polyol. Is done. Further, a polyol compound obtained by condensing these polyol compounds with p-aminobenzoic acid and having an active hydrogen group as an aromatic amino group can also be used.
[0027]
Polyether polyols include polyhydric alcohols such as ethylene glycol and diethylene glycol, and at least one of bifunctional active hydrogen compounds such as water and at least one of cyclic ether compounds such as propylene oxide, ethylene oxide, butylene oxide, and tetrahydrofuran. The polyol polyol compound which is a polyoxyalkylene glycol obtained by adding one kind by ring-opening polymerization is exemplified.
[0028]
Examples of the polyester polyol include one or more glycol compounds such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, and cyclohexanedimethanol, and glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, and terephthalic acid. Acid, isophthalic acid, dimer acid, hydrogenated dimer acid or other low molecular weight dicarboxylic acids or condensation polymers with one or more of oligomeric acids, cyclic esters such as propiolactone, ε-caprolactone, valerolactone And polyesterols such as ring-opened polymers of the above.
[0029]
As the acrylic polyol, a hydroxyl group obtained by polymerizing an unsaturated monomer containing a (meth) acrylic acid ester with an organic peroxide-containing initiator in the presence of an organic sulfonic acid compound, particularly in the presence of an alcohol compound, A telechelic acrylic polyol which is a containing acrylic polymer is exemplified as a suitable polyol compound. Examples of the polyester-polyether polyol include a polyol compound obtained by ring-opening addition of ε-caprolactone to a polyether polyol.
[0030]
The active hydrogen group-containing compound to be reacted with the isocyanate group-terminated prepolymer is referred to as a chain extender in the technical field of polyurethane, and is a compound having a molecular weight of about 500 or less. Specifically, aliphatic low molecular weight glycols and triols represented by ethylene glycol, propylene glycol, 1,4-butanediol, trimethylolpropane, etc., methylenebis-o-chloroaniline (MOCA), dicyclohexylmethane-4, Aromatic diamines such as 4′-diamine, aromatic diols such as 1,4-bishydroxyethoxybenzene (Cuamine H (manufactured by Ihara Chemical Co.)), m-xylylene diol (manufactured by Mitsubishi Gas Chemical Company), etc. Can be used. Two or more chain extenders may be used in combination.
[0031]
The non-reactive gas used to form the fine bubbles is preferably a gas composed of only a normal-temperature gas component that does not react with an isocyanate group or an active hydrogen group and is not flammable, and specifically, Nitrogen, oxygen, rare gases such as helium and argon, and mixed gases thereof are exemplified. The use of air or nitrogen from which moisture has been removed by drying is most preferable in terms of cost.
[0032]
The silicon-based surfactant used in the present invention is a silicon-based nonionic surfactant. By using such a surfactant, the physical properties of the polyurethane foam are not impaired, and the bubbles are fine and uniform. A polyurethane foam elastic body can be obtained stably. Such a silicon-based nonionic surfactant is used as a foam stabilizer in the technical field of polyurethane, and uses a polydimethylsiloxane having an average molecular weight of 1,000 to 8,000 and a graft copolymer of polydimethylsiloxane and polyalkylene oxide. Is preferred. Specifically, silicone foam stabilizers SH-190, SH-192, SH-193, SF-2965, SF-2962, etc. (manufactured by Toray Dow Corning Silicone Co., Ltd.), L-5340, L-5366, L-5309, etc. (Manufactured by Nippon Unicar Co., Ltd.) and B8465 (manufactured by Teha Goldschmidt). These silicon-based surfactants are appropriately selected and used in consideration of the compatibility with the isocyanate group-terminated prepolymer to be used.
[0033]
The addition amount of the silicon-based surfactant is preferably 0.5 to 10% by weight based on the total amount of the raw material components. If it is less than 0.5% by weight, a foam having fine cells may not be obtained, and if it exceeds 10% by weight, the physical properties of the polyurethane foam may be deteriorated.
[0034]
The average cell diameter of the polyurethane foam elastic body can be set and controlled by appropriately selecting and adjusting conditions such as the type and amount of the silicon-based surfactant to be used, the amount of stirring, and the viscosity of the raw material to be used. It is possible.
[0035]
The stirring time in the foam dispersion manufacturing process varies depending on the performance of the stirrer, the viscosity of the mixture of the isocyanate group-terminated prepolymer and the silicone-based surfactant that forms the polyurethane foam elastic body, but is stable for at least 30 seconds. It is more preferably about 1 to 10 minutes to prepare a cell dispersion. The stirring time needs to be longer than the stirring time for producing an ordinary polyurethane foam using a blowing agent such as a halogenated hydrocarbon or water.
[0036]
In the foam dispersion manufacturing process, as a stirring device for dispersing the non-reactive gas into fine bubbles and dispersing it in a mixture containing an isocyanate group-terminated prepolymer as a main component, a known stirring device can be used without particular limitation, and Specific examples include a Henschel mixer, a homogenizer, a dissolver, a twin-screw planetary mixer (planetary mixer), and a multi-screw stirrer. However, it is not preferable to use a stirrer that causes a strong temperature rise by stirring. The shape of the stirring blade of the stirring device is not particularly limited, but the use of a whipper-type stirring blade is particularly preferable since fine bubbles can be obtained.
[0037]
The stirring in the mixing step of mixing the bubble dispersion liquid and the active hydrogen group-containing compound (chain extender) does not need to be particularly stirring to form fine bubbles, and it is preferable to use a stirring device that does not involve large bubbles. As such a stirrer, a planetary mixer is preferable, but there is no problem even if the same stirrer is used as the stirrer in the bubble dispersion liquid production process, and the rotational speed of the stirrer is adjusted as necessary. It is also preferable to adjust the stirring conditions such as the use.
[0038]
The conditions of the cell dispersion production process are not particularly limited as long as fine cells are formed and a cured product having a predetermined shape is obtained, but the temperature is not lower than the melting point of the prepolymer, and is generally 0%. C. to 140.degree. C., more preferably 20 to 120.degree.
[0039]
The temperature in the mixing step is not particularly limited as long as the bubble dispersion liquid does not solidify and the added active hydrogen group-containing compound (chain extender) does not crystallize. The higher the temperature, the faster the curing reaction between the isocyanate group and the active hydrogen group proceeds, and the shorter the flow time of the reactive composition in the molding step. Therefore, a lower temperature is preferable.
[0040]
In the method for producing a run-flat tire support of the present invention, heating and post-curing the foam that has been reacted until the reactive composition has flowed into the mold and no longer flows, the physical properties of the polyurethane foam elastic body Is very effective. The conditions in which the foam dispersion is poured into a mold and immediately placed in a heating oven to perform post-curing may be employed. Even under such conditions, heat is not immediately transmitted to the reaction components, so that the bubble diameter does not increase. The curing reaction is preferably performed at normal pressure because the bubble shape is stabilized.
[0041]
In the method for producing a run flat tire support of the present invention, a catalyst that promotes a polyurethane reaction may be used. As the catalyst, a known catalyst such as a tin catalyst or a tertiary amine catalyst in the field of polyurethane can be used without limitation.
[0042]
The production of the microcellular polyurethane foam elastic body of the present invention may be a batch system, and each component and a non-reactive gas are continuously supplied to a stirrer and stirred, and a cell dispersion or a chain extender is added. A continuous production system in which the mixed reactive composition is sent out and injected into a mold may be used.
[0043]
The run flat tire support of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view illustrating the internal structure of a run flat tire. The run flat tire 10 has a tire 12 and a ring-shaped support 14 mounted on a rim 16. The shape of the support 14 is smaller than the shape of the tire internal space. The rim 16 is a one-piece rim on which a support mounting portion 17 is formed in consideration of mounting of the support 14.
[0044]
FIG. 2A shows a cross section taken along line XX of FIG. The support 14, which is a core, has a rectangular cross section, and is externally fitted to the support mounting portion 17 of the rim 16. The inner diameter of the support 14 is set to a diameter close to the maximum outer diameter including the rim flange. In the vicinity of the inner peripheral surface of the support 14 which is in contact with the outer peripheral surface of the rim, a reinforcing fiber layer for preventing the support from expanding due to the centrifugal force and moving up from the rim due to the centrifugal force during normal running without the run-flat state. Is provided. In this example, an example is shown in which a one-piece rim on which the support mounting portion 17 is formed is used. The cross-sectional shape of the support 14 is not particularly limited, but is preferably a flat shape having a longer tire width direction in consideration of the stability during running in the run flat state.
[0045]
FIG. 2B shows an example in which a split rim is used. Since the split rim is a commonly used rim, the cost of the rim is small and advantageous as compared with FIG.
[0046]
The structure of the rim on which the run flat tire of the present invention is mounted is not particularly limited, and the rim shown in FIG. 2A and the split rim shown in FIG. A split rim or the like can also be used.
[0047]
Although the support shown in FIGS. 2A and 2B has a rectangular cross section, the shape is not limited to this, and the shape on the inner diameter side does not crack even when subjected to compressive deformation. Forming is also a preferred embodiment.
[0048]
FIG. 3 illustrates another embodiment of the support, and FIG. 4 is a sectional view taken along line YY of FIG. The support 21 has a concave portion formed on a side portion. The support 21 includes an outer peripheral portion 29 and an inner peripheral portion 25, and concave portions 23 and 24 are formed on side portions. A reinforcing fiber layer 18 is provided in the vicinity of the inner peripheral surface of the inner peripheral portion 25 on the contact side with the rim, as shown in FIG. The concave portion forming position for reducing the weight is not limited to the side portion, and may be formed on the surface of the outer peripheral portion in contact with the inner surface of the tread, or may be provided on both the side portion and the outer peripheral portion. .
[0049]
The shape and number of the concave portions 23 and 24 are not particularly limited as long as the support 21 satisfies a requirement such as a predetermined mechanical strength. FIGS. 3 and 4 show an example of a rectangular parallelepiped shape, but may have a half egg shape. The larger the volume ratio of the concave portions, the more the weight of the support 21 can be reduced. The size of the rectangular parallelepiped recess shown in FIGS. 3 and 4 is determined by the height H, the depth D, and the angle θ corresponding to the length in the circumferential direction.
[0050]
FIG. 5 illustrates a side view and a top view of the arrangement of the concave portions formed on the side of the support 21. FIG. 5A is an example corresponding to FIG. 3 in which the concave portions 23 and 24 are alternately arranged so as not to overlap in a side view, and FIG. This is an example in which they are arranged in parallel at the same position. In the example illustrated in FIG. 5, the example illustrated in FIG. 5B has a large number of concave portions, and the volume ratio of the concave portions is large, resulting in a lighter support.
[0051]
As the reinforcing fibers constituting the reinforcing fiber layer, known reinforcing fibers can be used without limitation. Examples thereof include polyamide fibers such as nylon 6,6, polyester fibers such as polyethylene terephthalate, aramid fiber, glass fiber, and steel cord. The reinforcing fibers may be monofilaments and thus may be like piano wires. These reinforcing fibers are preferably used after being subjected to an adhesive treatment for improving the adhesiveness to the polyurethane foam.
[0052]
【Example】
Hereinafter, examples that specifically show the configuration and effects of the present invention will be described.
<Manufacture of support>
(Example 1)
5000 g (100 parts by weight) of an isocyanate group-terminated prepolymer adiprene L-100 (manufactured by Uniroyal) is dissolved at 80 ° C. in a 20 L container, and a silicon-based nonionic surfactant SH-192 (Toray Dow Corning Silicone Co., Ltd.) 150 g (3 parts by weight) was added thereto, and the mixture was stirred at a high speed using a mixer in the air to prepare a foam dispersion. Stirring was performed until the volume of the foam dispersion became twice the used isocyanate group-terminated prepolymer. After adjusting the temperature of the cell dispersion to 50 ° C., 605 g (12.1 parts by weight) of MOCA (manufactured by Ihara Chemical Co.) dissolved at 120 ° C. was added, and the mixture was stirred and mixed at a low speed using the same mixer. A reactive composition was obtained. The obtained reactive composition was poured into a mold whose temperature was adjusted to 100 ° C., and cured at 100 ° C. for 8 hours to obtain a support. The support had a ring shape with a rectangular cross section having an outer diameter of 510 mm, an inner diameter of 420 mm, and a width of 110 mm.
[0053]
(Example 2)
A support was produced in the same manner as in Example 1 except that 5000 g (100 parts by weight) of adiprene L-167 (manufactured by Uniroyal) was used as the isocyanate group-terminated prepolymer, and 17.5 parts by weight of MOCA was used.
[0054]
(Example 3)
A support was produced in the same manner as in Example 2. However, the support has the concave shape shown in FIG. 5A, and the concave formed on the side has H of 30 mm and D of 45 mm, and has a circumferential angle θ of 18.5 °. , 8 pieces on one side, a total of 16 pieces are formed.
[0055]
(Example 4)
A support was produced in the same manner as in Example 2. However, the support has the concave shape shown in FIG. 5B, and the concave formed on the side has H of 30 mm and D of 45 mm, and has an angle of θ = 18.5 ° in the circumferential direction. , 16 pieces on one side, a total of 32 pieces are formed.
[0056]
<Evaluation>
(Density) A cube of 10 mm × 10 mm × 10 mm was cut out from a molded article of the support, and the weight was measured.
[0057]
(Average bubble diameter) The size of each bubble was measured from a SEM photograph of the cut surface of the support, and the average was determined for a range of 1 mm x 1 mm.
[0058]
(Compression Modulus) A 10 mm × 10 mm × 10 mm cube was cut out from a molded product of the support and measured using a universal testing machine Instron 4301 (manufactured by Instron Japan). The measurement conditions were a temperature of 23 ° C., a humidity of 65% RH, and a crosshead speed of 1.27 mm / min.
[0059]
(75 mm compression strength) The support was compressed by 75 mm in the radial direction, and the strength was measured. The measurement was performed using a universal testing machine, Instron 4301 (manufactured by Instron Japan). The measurement conditions were a temperature of 23 ° C., a humidity of 65% RH, and a crosshead speed of 10 mm / min.
[0060]
(Displacement under a load of 500 kg) When the support (inner diameter 420 mm) is externally fitted to a ring-shaped iron fitting having an outer diameter of 420 mm, an inner diameter of 400 mm, and a width of 110 mm, and compressed to a load of 500 kg under the same apparatus and conditions as the 75 mm compression strength. Was measured.
[0061]
The evaluation results are shown in Table 1 below.
[0062]
[Table 1]

From the above results, it can be seen that the support for a run flat tire of the present invention is lighter and has a smaller number of cells than a conventional polyurethane support, and is composed of a closed-cell foam. In addition, the gas constituting the air bubbles was air, and the shape stability over time was excellent.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating the internal structure of a run flat tire. FIG. 2 is a cross-sectional view illustrating the structure of a run flat tire. FIG. 3 is a perspective view illustrating another embodiment of a run flat tire support having a concave portion. FIG. 4 is a cross-sectional view of a run flat tire support having a concave portion. FIG. 5 is a partial side view illustrating the arrangement of concave portions formed in the support and a top view corresponding thereto.

Claims (7)

A ring-shaped run flat tire support composed of a polyurethane foam elastic body and attached to a rim,
The run-flat tire support, wherein the polyurethane foam elastic body is a foam formed of fine closed cells filled with a non-reactive gas in cells having an average cell diameter of 20 to 200 µm. Run flat tires support according to claim 1 density of 0.3 to 0.8 g / cm ^3. A method for producing a ring-shaped run flat tire support composed of a polyurethane foam elastic body and mounted on a rim,
A bubble dispersion liquid which is obtained by adding a silicon-based surfactant to an isocyanate group-terminated prepolymer, stirring and mixing with a non-reactive gas, and dispersing the non-reactive gas as fine bubbles in the isocyanate group-terminated prepolymer to form a bubble dispersion liquid. A manufacturing step, a mixing step of mixing an active hydrogen group-containing compound with the foam dispersion to form a reactive composition, and a polyurethane having fine closed cells by injecting the reactive composition into a mold and reaction-curing the mixture. A method for producing a run flat tire support, comprising a molding step of forming a foam elastic body. The method for producing a run-flat tire support according to claim 3, wherein the polyurethane foam elastic body has an average cell diameter of 20 to 200 m. The density of the polyurethane foam elastic body, 0.3 to 0.8 g / cm ³ A method of manufacturing a run-flat tire support according to claim 3 or 4. A run-flat tire using the run-flat tire support according to claim 1. A run-flat tire using a support manufactured by the manufacturing method according to claim 3.

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