JP2003048412A - Safety tire, and foaming composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety tire enabling the stable traveling even when the tire is damaged without sacrificing the rolling resistance and the ride quality during the normal traveling before the tire is damaged. SOLUTION: An internal space of a hollow doughnut-shaped tire is divided into a plurality of chambers, the gas is filled in at least one of the plurality of chambers, a compound material having closed bubbles is disposed in at least one of the remaining chambers, the void content of the compound material is set to be between 80.00 vol.% and 98.75 vol.%, the internal pressure at 25 deg.C of the bubbles in the compound material is set to be >=150 kPa by the absolute pressure, and the continuous phase of the compound material contains at least a nylon resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety tire which enables normal running even after being damaged, and more particularly to a safety tire which is excellent in durability and riding comfort in running after damage to the tire. .

[0002]

2. Description of the Related Art In a pneumatic tire, for example, a passenger car tire, the internal pressure (absolute pressure, the same applies hereinafter) 250 to 350
By enclosing air under a pressure of about kPa, tension is generated in the tire skeleton portion such as the carcass and belt of the tire, and this tension enables deformation and restoration of the tire with respect to input to the tire. That is, by maintaining the internal pressure of the tire within a predetermined range, a constant tension is generated in the skeleton of the tire to impart a load supporting function and enhance rigidity, such as driving, braking and turning performance, It gives the basic performance required for vehicle running.

When the tire held at the predetermined internal pressure is damaged, air leaks to the outside through the damage and the internal pressure of the tire is reduced to atmospheric pressure. Most of the tension generated in the part is lost. Then, as a result of losing the load supporting function, driving, braking and turning performance obtained by applying a predetermined internal pressure to the tire,
A vehicle equipped with the tires becomes unable to run.

Therefore, many proposals have been made for safety tires that enable traveling even in a punctured state. For example, as a pneumatic safety tire for automobiles,
Various types such as those having a double wall structure, those in which a load supporting device is arranged in the tire, and those in which tire side portions are reinforced have been proposed. Among these proposals, the technique actually used is a tire having a side reinforcing layer made of relatively hard rubber on the inner surface from the shoulder portion to the bead portion centering on the sidewall portion of the tire. This type of tire is mainly used as a so-called run-flat tire having a flatness ratio of 60% or less.

However, the method of adding the side reinforcing layer is as follows.
Since the tire weight is increased by 30 to 40% and the vertical spring constant of the tire is increased, there is a disadvantage that rolling resistance is significantly deteriorated and riding comfort during normal running before puncture is deteriorated. Therefore, it is a technology that is still lacking in versatility because it adversely affects the performance, fuel efficiency, and environment during normal driving.

On the other hand, in a pneumatic tire having a high tire cross-section height and an aspect ratio of 60% or more, in order to avoid heat generation in the sidewall portion due to relatively high speed and long distance running, a core or the like is formed on the rim. A run flat tire having a structure in which an inner support is fixed to support a load during puncture is mainly applied.

However, the tire cannot withstand the local repetitive stress generated between the tire and the internal support during the run-flat after the puncture, and as a result, the mileage after the puncture is about 100 to 200 km. Was limited to. In addition, the work of assembling the tire on the rim after disposing the inner support inside the tire is complicated and requires a long time, which is also a problem. In this regard, there has been proposed a device for facilitating the insertion of the internal support by providing a difference in the rim diameter between the one end side and the other end side in the width direction of the rim, but the sufficient effect has not been obtained.

In order to extend the mileage after puncture of a run flat tire having an internal support, it is effective to add a frame material to make the tire structure heavier.
The addition of the skeletal material deteriorates rolling resistance and riding comfort during normal use, so it is not practical to adopt this method.

Further, these conventional safety tires can exhibit the running ability after puncture to some extent on a normal asphalt road surface or a road surface having a relatively high friction coefficient such as an uneven road surface. However, on a road surface having a low coefficient of friction, which is represented by an icy road or a snowy road in winter, if the punctured tire is not the drive wheel but the idle wheel, a serious drawback is revealed. That is, in the state before puncture, the tire flexure is naturally small and maintains a shape close to a circle, so when the vehicle starts to move due to the driving force generated from the driving wheels at the time of start, the idle wheels will move as the vehicle moves. Start rolling. However, in the state after the puncture, the tire is largely bent, and the shape deviates from the circular shape. The idle wheel is a wheel that cannot roll on its own, that is, cannot generate a driving force. Therefore, the rolling of the idle wheel depends on the movement of the vehicle and the friction coefficient of the road surface. Therefore, on a road surface with a low coefficient of friction, even if the vehicle starts to move, the tire that has deflected significantly due to puncture and deviates from the circular shape due to the low coefficient of friction on the road surface will cause a large slip in the ground contact tread and roll. Without being dragged, it will move with the vehicle. The reason is that the ground contact pressure distribution in the ground contact tread becomes extremely non-uniform along with a large bending deformation as compared with the relatively uniform state before puncture. Such a situation occurs not only at the time of starting but also at the time of braking. Therefore, a "driving force adjustment function (traction control)" that is a function that is installed in the vehicle in advance to supplement safe driving on a road surface with a low friction coefficient, and a "braking force adjustment function" that avoids tire lock during braking (Anti-lock brake system) "is not fully exerted, and there is a risk that the vehicle may become out of control due to malfunction. In particular,
Needless to say, in a vehicle in which the front wheels are idle wheels and the steered wheels, and the rear wheels are the drive wheels, the puncture of the front wheels causes the steering performance to be extremely reduced, resulting in a very dangerous state.

Further, a tire in which a composite having closed cells is filled in an inner cavity of an assembly of a tire and a rim to be assembled to the tire is disclosed, for example, in Japanese Patent Laid-Open Nos. 6-127207 and 6-183226. It is described in, for example, Kaihei 7-186610 and JP-A-8-332805. The tires proposed therein are mainly limited to special or small tires such as agricultural tires, rally tires, motorcycle tires and bicycle tires. Therefore, its application to tires for passenger cars and tires for trucks and buses, such as tires that emphasize rolling resistance and riding comfort, has been unknown. Moreover, since the foaming ratio of each of the composites is low, the composite having air bubbles has a large weight, and it is inevitable that vibration and riding comfort and fuel economy are deteriorated. Therefore, it was not functionally sufficient to replace the high pressure air of conventional tires.

Further, Japanese Patent No. 2987076 discloses a puncture tire in which a foam filler is inserted in the inner peripheral portion. However, in addition to the disadvantage that the internal pressure of bubbles is extremely close to the atmospheric pressure, Since is a urethane type, energy loss due to intermolecular hydrogen bond of urethane group is large and self-heating property is high. Therefore, when the urethane foam is filled in the tire, the foam heats up due to repeated deformation during rolling of the tire, resulting in a significant decrease in durability. In addition, since it is difficult to form air bubbles independently of each other, it is difficult for air bubbles to communicate with each other and it is difficult to retain gas, and the desired tire internal pressure (load supporting ability or deflection suppressing ability, the same applies below) is obtained. There are disadvantages that cannot be obtained.

Further, in Japanese Unexamined Patent Publication (Kokai) No. 48-47002, the outer circumference of a multi-cell body mainly composed of closed cells is integrally covered with an outer coating film such as rubber or synthetic resin having a thickness of 0.5 to 3 mm. A puncture-less tire has been proposed in which a large number of expanded pressure bubbles that have been sealed are filled in a tire and the tire is maintained at a specified internal pressure. In this technique, in order to make the bubble internal pressure of the foam higher than normal pressure, the amount of the foaming agent compounded in the closed foam forming compound material that becomes the expansion pressure bubble is at least equal to or more than the tire internal volume. The amount of foaming agent that generates gas is set so that at least the same performance as ordinary pneumatic tires is aimed at.

In the above-mentioned technique, in order to prevent the gas in the bubbles in the expanded pressure bubble from being dissipated, the outer envelope film is integrally encapsulated and sealed. The material of the outer envelope film is exemplified by an automobile. Materials such as tubes for use or formulations for forming the tubes. In other words, a soft elastic envelope film mainly composed of butyl rubber having a low nitrogen gas permeability, which is used for a tire tube or the like, is used for covering and sealing, and many of these are filled in the tire. As the manufacturing method, an unvulcanized tire tube is used as the soft elastic envelope film, and an unvulcanized closed-cell body-forming compounded raw material is used as the expansion pressure bubble body, and after arranging a large number of these inside the tire / rim assembly, A foam-filled tire is obtained by foaming by heating. The atmospheric air inside the tire due to the expansion of the foam is naturally exhausted from the exhaust small holes formed in the rim.

Since the internal pressure of passenger car tires is generally set to about 250 to 350 kPa in absolute pressure at room temperature, the above foam-filled tire is manufactured by heating during vulcanization molding. It is estimated from the equation of state of gas that the internal pressure is approximately 1.5 times the internal pressure in the state of (140 ° C.). However, at such a pressure level, it is unavoidable to generate blown due to insufficient vulcanization pressure, particularly in the portion of the soft elastic envelope film composed of the unvulcanized tire tube. In order to avoid this blown phenomenon, it is necessary to greatly increase the compounding amount of the foaming agent to increase the pressure generated by foaming and increase the heating temperature. However, the method of increasing the blending amount of the foaming agent makes it difficult to use it as a substitute for the conventional pneumatic tire because the internal pressure at room temperature greatly exceeds 400 KPa due to the increase of the blending amount of the foaming agent. In addition, the method of increasing the heating temperature causes a great damage to the tire due to heat aging and significantly deteriorates the durability of the tire, which causes a problem in the durability in long-term use. On the other hand, inside the tire / rim assembly, a large number of expansion pressure bubbles wrapped in a soft elastic envelope film are arranged, but the friction between the soft elastic envelope films caused by the blow, the tire inner surface and the rim inner surface are generated. There is a big problem in terms of durability such as friction with. From the above, it can be said that the above-mentioned problem is a large defect caused by disposing a large number of divided expanded pressure bubbles, unlike the case where the expanded pressure bubbles have an integral donut shape. Also, the exhaust small hole opened on the rim is
Although it is effective for naturally exhausting the normal pressure air inside the tire due to the expansion of the expansion pressure bubble, it becomes a dissipation path for the gas in the bubble in the expansion pressure bubble, so it can withstand long-term use. Not a thing.

Further, as the soft elastic envelope film, a compounded composition mainly composed of butyl rubber having a small nitrogen gas permeability such as a tire tube is used. However, since butyl rubber has an extremely slow vulcanization reaction rate, A large heating time is required at a temperature of about 140 ° C. to complete the reaction. This means that the cross-linking density of the soft elastic envelope coating is insufficient, and it is needless to say that it is one of the factors that cause separation between the divided soft elastic envelope coatings. Further, the extension of the heating time further increases the damage of the tire due to the above-mentioned heat aging, so that the deterioration of the durability cannot be avoided and is not a good measure.

[0016]

Therefore, the present invention is
An object of the present invention is to provide a safety tire that enables stable running even after tire damage without sacrificing rolling resistance and riding comfort during normal running before tire damage.

Another object of the present invention is to provide a composite suitable as a filler for the inside of the above-mentioned safety tire and a foamable composition which is a raw material thereof.

[0018]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the inventors have found that in order to always maintain the internal pressure of the tire properly, the tire internal It has been found that it is effective to give a structure in which gas does not easily leak. That is, the gist of the present invention is as follows.

(1) The inner space of a hollow donut-shaped tire is divided into a plurality of chambers, at least one of the plurality of chambers is filled with gas, and a composite having closed cells is arranged in the remaining at least one chamber. A safety tire having a cell content of 80.00% by volume to 98.75% by volume of the composite, and the internal pressure at 25 ° C. of the closed cells contained therein is 1 in absolute pressure.
A safety tire having a pressure of 50 kPa or more, wherein the continuous phase of the composite contains at least a nylon resin.

(2) A safety tire according to the above (1), characterized in that the partition wall defining the plurality of chambers is made of a rubber composition containing 50 mass% or more of butyl rubber.

(3) In the above (1) or (2), the internal pressure at 25 ° C. of the closed cells contained in the composite is 20 in absolute pressure.
A safety tire having a pressure of 0 kPa or more.

(4) A safety tire according to the above (1), (2) or (3), characterized in that the continuous phase of the composite is made of nylon resin and butyl rubber.

(5) A safety tire according to the above (1), (2) or (3), wherein the continuous phase of the composite is made of a nylon resin.

(6) In any one of (1) to (5) above, the nylon resin is selected from nylon 6, nylon 11, nylon 12, nylon 6/66 copolymer and nylon 6/12 copolymer. A safety tire characterized by being at least one of the following:

(7) In any one of the above (1) to (6), nitrogen, air, carbon dioxide, a linear or branched aliphatic hydrocarbon having 3 to 8 carbon atoms is contained in the bubbles of the composite. And a safety tire having at least one gas selected from the group consisting of alicyclic hydrocarbons having 3 to 8 carbon atoms.

(8) In any one of (1) to (7) above, the continuous phase of the composite has a gas permeability coefficient of 300 × 10 ⁻¹² (cc · cm / cm ² · s · cmH at 30 ° C.).
g) A safety tire characterized by being:

(9) In any of (1) to (8) above,
The continuous phase of the composite has a gas permeability coefficient of 20 at 30 ° C.
× 10 ⁻¹² (cc · cm / cm ² · s · cmHg) or less, a safety tire.

(10) In any one of the above (1) to (9), the continuous phase of the composite has a gas permeability coefficient of 2 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg) at 30 ° C.
A safety tire characterized by being:

(11) In any one of the above items (1) to (10), an inner liner layer is provided on the inner peripheral surface of the tire, and the inner liner layer comprises nylon resin having a melting point of 170 to 230 ° C. and isobutylene paramethyl. The gelling ratio of the elastomer component including the halide of the styrene copolymer is 50 to 50.
A safety tire comprising a thermoplastic elastomer composition dynamically vulcanized to 95%.

(12) In the above (11), the inner liner layer has a gas permeability coefficient of 20 × 10 at 30 ° C.
A safety tire having a pressure of ⁻¹² (cc · cm / cm ² · s · cmHg) or less.

(13) A polymer containing at least a nylon resin and dinitrosopentamethylenetetramine (DP
T), azodicarbonamide (ADCA), paratoluenesulfonylhydrazine (TSH) and its derivatives, and at least one foaming agent selected from oxybisbenzenesulfonylhydrazine (OBSH).

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION A safety tire according to the present invention will be described below with reference to FIGS. 1 and 2 showing cross sections in the width direction. That is, the safety tire of FIG. 1 has a plurality of chambers in the inner space of the tire 1, and in the illustrated example, the tire 1
Is divided into two chambers 2 and 3 which are continuous in the circumferential direction, and at least one of these chambers, the chamber 2 in the illustrated example, is filled with a gas such as air or nitrogen, and the remaining at least one chamber, the illustrated chamber 3, a composite 4 composed of a resin continuous phase and closed cells is arranged. The structure of the tire 1 is not particularly limited as long as it is a tire for various automobiles, such as a tire for passenger cars, which is generally used. For example, the illustrated tire is a general automobile tire, and a belt 7 and a tread 8 are sequentially arranged radially outward of a crown portion of a carcass 6 extending in a toroidal shape between a pair of bead cores 5. In the figure, reference numeral 9 is an inner liner layer and 10 is a rim.

The composite 4 has closed cells in which individual cells are surrounded by partition walls and isolated, and the content of bubbles in the composite 4 is from 80.00% by volume to 9% by volume.
It is important that the internal pressure at 8.75% by volume and the contained closed cells at 25 ° C. is 150 kPa or more in absolute pressure. That is, when the bubble content is less than 80.00% by volume, when the composite is deformed inside the tire, stress is sporadically concentrated in the continuous phase portion between the bubbles, and cracks are likely to occur in the continuous phase, which causes repeated repetition. The durability of the composite against deformation is significantly reduced. On the contrary, the bubble content rate is 98.75.
When the content is more than the volume%, the degree of damage to the composite due to the tire damage becomes large, and the propagation speed also increases, and in this case as well, the durability of the composite against repeated deformation remarkably decreases.

Here, the bubble content rate is a percentage of the volume of the bubble volume with respect to the volume of the composite body placed inside the tire, and is calculated by the following equation. You can Bubble content = {1- (used volume of resin or composition constituting composite / indoor volume)} × 100

Further, the internal pressure at 25 ° C. of the closed bubbles is 1
It is 50 kPa or more, preferably 200 kPa or more.
That is, the internal pressure of the closed cells at 25 ° C is 150 kP
If it is less than a, the flexure of the composite becomes large and the amount of repeated deformation at the time of rolling of the tire becomes large, so that the fatigue history of the composite during normal running before tire damage increases, and the composite caused by tire damage The rate of damage progression increases as the amount of deformation increases, and in this case also, the durability of the composite against repeated deformation remarkably decreases, and the performance during running in a tire-damaged state becomes insufficient.

Here, in the safety tire of FIG. 1, as a device for maximizing the durability of the composite, the chamber 2 is filled with a gas at preferably about 200 to 300 kPa,
During normal driving (before tire damage), it is advantageous to positively compress the composite in the tire. With this device, it is possible to reduce the load bearing ratio of the complex during normal running, and it is possible to reduce the fatigue history associated with repeated deformation during rolling of the tire. Therefore, even if the air filled between the composite and the tire inner surface is dissipated due to tire damage, the running performance in a tire damaged state is significantly improved compared to the case where the above method is not adopted.

By arranging the composite body 4 as described above, a necessary internal pressure is applied to the tire. That is, by arranging the composite body 4 in the chamber 3 on the inner peripheral surface side of the tire and applying a predetermined internal pressure to the tire together with the gas in the chamber 2, tension may be generated in the tire skeleton portion such as the carcass and belt of the tire. Realized the structure. Therefore, since an appropriate internal pressure is applied to the tire by the composite body 4 and the chamber 2, it is not necessary to regulate the tire structure itself, and a general-purpose tire and a general-purpose rim can be utilized to newly provide a safety tire. .

The tire in which the composite body 4 is arranged inside is characterized in that even if the tire is damaged, the tension of the case does not easily decrease as in a normal pneumatic tire. Because when the tire is damaged, a part of the composite 4 is damaged on the inner surface of the tire near the damage,
The gas in some closed bubbles in this damage can escape to the outside of the tire. However, this phenomenon is similar to that of a conventional pneumatic tire, in which the internal pressure drop only occurs in a very small area, and therefore the tire loses its tension as a case due to partial damage of the composite body 4. In addition, the conventional pneumatic tire does not fall into a flat state. Further, the probability of damage to the composite body 4 due to the external damage of the tire is extremely low, and even if the composite body 4 is damaged, its area is extremely limited. However, it cannot be deteriorated so as to impair the tire function.

Moreover, although the pressure in the vicinity of the damaged closed bubbles is reduced to the atmospheric pressure, the closed bubbles in the peripheral portion are 150 kPa.
Since it has the above-mentioned internal pressure, it expands when the surrounding pressure decreases, and as a result, the region of the damaged independent bubbles is compressed and the damaged site is closed, and so-called self-repair becomes possible.

The above state is a state in which the composite directly or indirectly bears a load to provide the minimum tire internal pressure required for running. The tire deflection in this state is relatively small, and it is possible to maintain a circular shape compared to the above-mentioned conventional safety tire, and thus it is possible to maintain a relatively uniform contact pressure distribution in the contact tread. By filling the particles of the present invention in a tire mainly used for road surface running in winter such as a studless tire, the basic performance of the studless tire is not deteriorated even after the tire is damaged. That is, even on a road surface having a low coefficient of friction such as on a snowy road, the driving performance such as driveability, braking performance, turning performance, etc. is not significantly deteriorated and the vehicle is not incapable of running.

Here, in order to apply a predetermined tire internal pressure by the composite 4, the gas sealed in the closed cells in the composite 4 at a predetermined pressure does not leak from the foam to the outside of the composite.
In other words, it is essential that the continuous phase of the closed cells in the composite 4 has a property that gas hardly permeates. That is, the continuous phase of the composite body 4 serving as a matrix of closed cells is
It is important to use a material having low gas permeability, specifically, it is essential that at least a nylon resin is contained, and more specifically, a nylon resin, or a material composed of a nylon resin and butyl rubber is suitable. This material is particularly effective for the present invention because it has flexibility for input due to tire deformation.

Particularly, as the nylon resin, nylon 6, nylon 11, nylon 12, nylon 6/6
At least one selected from 6-copolymers and nylon 6 / 12-copolymers is advantageously suitable. All of these materials have a low gas permeability coefficient and a low gas permeability, so that the gas inside the closed bubbles does not leak to the outside and the atmospheric pressure inside the closed bubbles can be maintained within a predetermined range. .

The continuous phase of the composite is then at 30 ° C.
Gas permeability coefficient is 300 × 10^-12(Cc · cm / cm
^Two· S · cmHg) or less, preferably at 30 ° C
Transmission coefficient is 20 × 10^-12(Cc · cm / cm^Two・
s · cmHg) or less, more preferably at 30 ° C.
Gas permeability coefficient is 2 × 10^-12(Cc · cm / cm^Two・
s · cmHg) or less is recommended. Why
The inner liner layer of a normal pneumatic tire
Gas permeability coefficient is 300 × 10^-12(Cc · cm / c
m^Two・ Sufficient internal pressure at a level below s ・ cmHg)
Considering the track record of retaining function,
However, the gas permeability coefficient at 30 ° C is 300 × 10
^-12(Cc · cm / cm^Two・ S ・ cmHg) or less
It was However, at this gas permeation coefficient level,
Since it is necessary to replenish the internal pressure about once a month,
20 × 10 from the point of nonce^-12(Cc · cm /
cm ^Two· S · cmHg) or less, more preferably 2 × 1
0^-12(Cc · cm / cm ^Two・ S ・ cmHg) or less
Is recommended.

As the gas forming the closed cells of the composite, nitrogen, air, a linear or branched aliphatic hydrocarbon having 3 to 8 carbon atoms and a carbon number of 3 are contained in the foam of the composite. To 8 selected from the group consisting of alicyclic hydrocarbons.

The method for forming a composite having closed cells is not particularly limited, but it is preferable to use a foaming agent.
Examples of the foaming agent include a thermally decomposable foaming agent that generates a gas by thermal decomposition, a high-pressure compressed gas and a liquefied gas. In particular, many of the thermally decomposable foaming agents are characterized by generating nitrogen, and the composite obtained by appropriately controlling the reaction has nitrogen in the bubbles.

When the resin continuous phase forming the composite is melted and filled in the tire with air at high pressure to form the composite, air remains in the bubbles. Furthermore, during the resin continuous phase polymerization, propane, butane, pentane, hexane, butane, octane, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane and cyclooctane are liquefied and dispersed in a reaction solvent. While there is also a method of emulsion polymerization, by which the propane, butane, pentane, hexane, butane, octane, cyclopropane, cyclobutane, cyclopentane cyclohexane, cycloheptane and cyclooctane gas components such as the liquid continuous phase It is possible to obtain expandable resin particles that are encapsulated in, and when this is filled into the tire and heated to form a composite, propane, butane, pentane,
Hexane, heptane, octane, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane and cyclooctane are included. The isomers of butane and pentane include isobutane, isopentane, neopentane, 2-methylpentane, 2,2-dimethylbutane, methylhexanes, dimethylpentanes, trimethylbutane, methylheptanes, dimethylhexanes and trimethylpentane. Can be mentioned.

Further, resin particles containing a liquefied gas such as propane, butane, pentane and hexane may be filled in the chamber together with the melt of the resin forming the continuous phase of the composite.

The desired tire can be obtained by heating and foaming the surface of the expandable resin particles coated with a surface active agent, an oil agent or the like in the tire. Furthermore, the target tire can also be obtained by preliminarily heating and foaming the resin particles containing the liquefied gas to form hollow beads having a substantially spherical shape, and compressing and filling the hollow beads into the tire.

Further, in arranging a large number of composites inside the tire according to the present invention, it is important to add a liquid that does not substantially swell a continuous layer of the composite inside the tire. By adding this liquid, it is possible to further enhance the sealing function of the tire damaged portion when the tire is damaged and further extend the traveling distance after the tire is damaged. That is, since the composite has a substantially spherical shape, it has high fluidity, and therefore, the inside of the tire and the rim assembly can be easily filled from an inlet having a small inner diameter such as a valve of the tire.
On the other hand, when the tire is damaged, the composite tends to blow out from the damaged portion to the outside of the tire and collects on the inner surface of the damaged portion. However, since the damaged route from the inner surface of the damaged portion to the outer peripheral surface of the tire has a complicated intricate shape instead of a straight line, the complex entering from the scratch on the inner surface of the tire is blocked on the way of the route, resulting in a large number of composites. The body gathers in a compressed state on the inner surface of the damaged part, and the damaged part is sealed by the composite. At that time, if a liquid is added to the inside of the tire together with the composite, it is possible to collect several to several thousand composites based on the affinity between the surface of the composite and the liquid and the viscosity of the liquid. Therefore, when a tire is damaged, it is possible to instantly fill the damaged portion with the composite body.

Further, since the liquid to be mixed has a significantly higher specific gravity than the composite, under normal running, a large amount of liquid will be distributed on the inner surface of the tire tread portion due to the centrifugal force associated with tire rolling. This indicates that there are many composites that are relatively large aggregates near the inner surface of the tire tread portion during normal running. Therefore, when the tire is damaged by stepping on a foreign substance or the like, most of the composite bodies that are aggregated through a relatively large amount of liquid quickly seal the damaged part, which is extremely effective.

In order to obtain a composite-filled tire in which a liquid is mixed, the following points should be noted in production. That is, when filling the tire, it is important that the composite is filled in a highly fluid state, in other words, in a dry state before being mixed with the liquid. The composite forms an aggregate by mixing with the liquid as described above. Therefore, the composite mixed with the liquid has extremely low fluidity, which makes it difficult to fill the tire. Therefore, the method of applying the liquid to be mixed to the inner surface of the tire or the inner surface of the rim before the filling or the method of injecting the liquid into the tire and the rim assembly after the filling of the composite is efficient and reliable.

The liquid used here does not swell the continuous phase of the composite or causes a chemical reaction, as described above, and preferably does not cause a swell or a chemical reaction with respect to the inner liner layer. Furthermore, it is required to have performance such as being stable against heat generation during traveling. For example, silicone oil and aliphatic polyhydric alcohols represented by ethylene glycol and propylene glycol can be cited.

The safety tire of the present invention is particularly characterized in that the internal pressure of the closed cells of the composite body disposed inside is a high pressure which has never been obtained. The following is a description of how to realize such a safety tire. Much depends on the new manufacturing method.
The manufacturing method will be specifically described below, but in any method, it is preferable to monitor the tire internal pressure and the tire internal temperature in the manufacturing process and appropriately control the generation and growth of bubbles.

The first method is to load a predetermined amount of the foamable composition into the tire, and then install the tire in the rim.
Then, the tire assembly is heated to foam inside the tire. The heating can be performed by using microwaves or electron beams in addition to the oven or steam, and this is the same in the following method.

The second method is to melt a raw material for the continuous phase of the composite and add a thermally decomposable foaming agent (including a foaming aid) to the inside of the tire assembly after the rim assembly. Inject, then heat the tire assembly to foam inside the tire.

The third method is, for example, a polymer hollow particle such as Expancel (trademark) in which butane, propane and its isomers or pentane and its isomers are liquefied and encapsulated, and a molten continuous phase. The following material is injected into the tire assembly after the rim is assembled, and then the tire assembly is heated to foam inside the tire.

The fourth method is to melt high-pressure air or high-pressure gas such as CO ₂ or N ₂ inside the tire after the rim is assembled in a state in which the material to be the continuous phase of the composite is melted and fluidity appears. At the same time, it is injected into the tire assembly to form a composite body inside the tire assembly.

In the fifth method, a foamable composition molded into an annular shape is placed inside a tire, the tire is mounted on a rim, and then the tire assembly is heated.
Foaming is performed inside the tire. The foamable composition does not necessarily have to be annular, but from the viewpoint of workability and uniform filling, it is preferably annular.

When the chamber 3 is filled with the composite material by the above-mentioned method, after the partition walls for partitioning the plurality of chambers have been installed in the tire assembly in advance, a gas having a volume equal to or larger than the tire inner volume is filled in the chamber 2. Encapsulate. At this time, the chamber 3 and the outside air need to communicate with each other through a valve or the like mounted on the wheel. Thereby, the volume of the chamber 3 can be substantially zero. Next, a negative pressure can be generated in the chamber 3 by sucking the gas filled in the chamber 2, and the negative pressure generated is used to introduce the foamable composition into the chamber 3. Meanwhile, the chamber 2 filled with gas can be formed. Further, in the chamber 3, a gas such as nitrogen or air can be mixed in addition to the composite.

A nylon resin or a polymer selected from nylon resin and butyl rubber is suitable for the continuous phase, and dinitrosopentamethylenetetramine (DPT), azodicarbonate is used as the thermally decomposable foaming agent. At least one selected from amide (ADCA), paratoluene sulfonyl hydrazine (TSH) and its derivatives, and oxybisbenzene sulfonyl hydrazine (OBSH) is suitable.

On the other hand, a tire usually has an inner liner layer on its inner peripheral surface. The inner liner layer comprises a nylon resin having a melting point of 170 to 230 ° C. and a halogen of isobutylene paramethylstyrene copolymer. And a thermoplastic elastomer composition in which an elastomer component containing a compound is dynamically vulcanized to a gelation rate of 50 to 95%,
preferable. This is because, unlike the conventional inner liner layer mainly composed of butyl rubber, by using a nylon resin as the continuous phase, the gas permeability becomes extremely low, so that the function of the inner liner layer can be enhanced. On the other hand, the gelling rate of the elastomer component containing the halide of isobutylene paramethylstyrene copolymer is 50 to 95%.
By using the dynamically vulcanized thermoplastic elastomer composition, it is possible to obtain an inner liner layer having excellent flexibility, heat resistance and durability. The inner liner layer having the above characteristics can create an environment in which the gas in the closed cells of the composite body can easily remain in the bubbles.

The gelation rate means the pelletized mixture after biaxial kneading, is subjected to Soxhlet extraction with acetone in a water bath for 8 hours, and the residue is further subjected to n-
It is a value calculated by the following formula by extracting the unvulcanized elastomer component with a solvent by Soxhlet extraction with hexane and measuring the weight of the acetone and n-hexane extract after solvent drying. Gelation rate (%) = [weight of total formulation − {(amount of acetone extracted + amount of n-hexane extracted) −amount of stearic acid}] / weight of total formulation × 100

[0063] Further, the inner liner layer, the gas permeability coefficient at 30 ° C. is ^{20 × 10 - 12 (cc ·} cm /
It is preferably not more than cm ² · s · cmHg). This is because even if the gas in the bubbles leaks from the composite for some reason, if the gas permeability of the inner liner layer is low enough, the gas in the bubbles in the composite will leak to the outside of the tire. This is because it is less likely to come out, which is advantageous in maintaining the internal pressure of the tire. That is, the gas permeability of the inner liner layer is a factor that directly determines the pressure retention of the tire as a pressure vessel. Of course, it is fundamental that the continuous phase forming the composite has low gas permeability, and on top of that, it is ideal to use the inner liner layer having low gas permeability.

In the safety tire shown in FIG. 2, the composite body 4 is arranged in the chamber 2 in the safety tire shown in FIG.
Is filled with gas, and the other structure is the same as that of the tire of FIG. That is, the complex 4 in the chamber 2 is filled with gas, for example, air in the chamber 3 so that the complex 4
The inner pressure is compensated for while shrinking the. In this case, when the tire is damaged, the air in the chamber 3 is dissipated to the outside, but the pressure difference generated after the air is dissipated causes the complex 4 to expand, and as a result, the internal pressure is sufficient to allow traveling a limited distance. That is, since the composite can exhibit the deflection suppressing ability and the load supporting function, the run flat tire has sufficient performance.

Here, the state of the partition wall that divides the plurality of chambers is
It will be described below. That is, the partition wall has a melting point of 170 to 23.
An elastomer component containing a 0 ° C. nylon resin and a halide of isobutylene paramethylstyrene copolymer,
It is preferably composed of the thermoplastic elastomer composition dynamically vulcanized to the gelation rate of 50 to 95%. The reason for this is that by using nylon resin as the continuous phase, gas permeability becomes extremely good, and as a result, the function as a tube can be enhanced. Further, by providing a thermoplastic elastomer composition in which an elastomer component containing a halide of an isobutylene paramethylstyrene copolymer is dynamically vulcanized to have a gelation rate of 50 to 95%, it is highly flexible,
In addition, a partition wall having excellent heat resistance and durability can be obtained.

Also in this partition, the gas permeability coefficient at 30 ° C. is 300 × 10 ⁻¹² (cc · cm / cm ² ·.
s · cmHg) or less, preferably 20 × 10 ⁻¹² (c
c · cm / cm ² · s · cmHg) or less, more preferably 2 × 10 ⁻¹² (cc · cm / cm ² · s · cmH)
g) The following is recommended. Because, even if the gas permeability of the continuous phase of the composite is high, if the gas permeability of the partition wall is low, the bubble gas in the composite is less likely to leak outside the partition wall, and the internal pressure of the tire is maintained. This is because it is advantageous to

[0067]

EXAMPLES Composites of various specifications shown in Tables 1 to 3 were applied to a tire having the structure shown in FIG. A safety tire was prototyped. The tire size is 185 / 70R14 and the rim size is 5.5J × 14. Where tire 1
Is in accordance with the general structure of the tire type and size. In addition, in Tables 1 to 3, the compounding species and compounding contents which are the continuous phase of the composite and the polymer species are as shown in Tables 4 to 6, and similarly, the compounding species of the inner liner layer are Tables 4 and 5. Table 7 shows the composition of the side reinforcing rubber.
, Respectively.

The bubble internal pressures shown in Tables 1 to 3 were calculated by the following formula (A) based on the following definitions. Bubble pressure (kPa) = [(Wt / ρs) / Vt] 101.325 ---- (A) where: Wt: Weight of the composite filled in the tire chamber Vt: Contents of the chamber used for filling Product ρs: Specific gravity of the composite sampled from the tire under atmospheric pressure, expressed as ρs = Ws / Vs, where Vs: Volume of the composite sampled from the tire under atmospheric pressure Ws: From the tire Weight of sampled complex

Inventive Example 14 and Comparative Example 18 in Table 3
The bubble internal pressure in was multiplied by the reciprocal of the coefficient defined by the following formula (B), that is, the compression ratio of the composite obtained by additionally filling the gas, with the bubble internal pressure obtained above. (Compression ratio of the composite due to filling with gas) = [Vt- {Vg / (Pg / 101.325)}] / Vt ---- (B) where Vg: added to the tire after the composite is filled Volume Pg of the filled gas under atmospheric pressure: Pressure of the gas additionally filled in the tire after filling the composite (kPa)

For each tire thus obtained, 50
The amount of deflection of the tire was measured before and after running on the drum at 00 km and a load of 450 kgf, and the amount of change in deflection before and after running on the drum (tire height of tire before running under load-tire height after running under load) ) Is indicated as an index when the tire height before running under load of each tire is 100. The smaller this index is, the better the result is.

By the way, one of the important abilities that a tire should exhibit is its load bearing ability. In a conventional tire, its ability is exhibited by filling the inside with air, and the internal pressure is measured in order to measure the amount of the ability. However, since the tire of the present invention basically does not have a gas such as air filled therein, the so-called internal pressure cannot be measured.

Here, being able to support the load means that
That is, the tire has a force capable of opposing the force from the outside. In the conventional tire, this force is exerted by the air inside, and in the tire of the present invention, this force is exerted by the complex filled inside. If the two are in opposition, the tire retains its original shape and does not hinder driving, but if the force from the inside of the tire decreases due to leakage of internal air, etc., the force from the outside Gradually transforms,
Deflection occurs. Leakage of air in the interior means that in a conventional pneumatic tire, the air filled in the tire leaks out of the tire, and in the tire of the present invention, gas contained in bubbles in the complex is Leaks inside, which in turn refers to leaks outside the tire. Therefore, in the present invention, the rate of increase in the amount of flexure of the tire is measured as an index for grasping the change in the load bearing capacity of the tire.

Further, the tire after running on the drum is
It was attached to a 000cc class passenger car, and then a tire with a diameter of 3mm and a length of 3cm was penetrated into the tread from the outside of the tire tread to cause trauma, and then a load equivalent to that for 4 passengers was applied. The test course was run at 90 km / h for a maximum of 500 km, and a passable distance of 200 km or more was passed. The results of these investigations are also shown in Tables 1 to 3.

[0074]

[Table 1]

[0075]

[Table 2]

[0076]

[Table 3]

[0077]

[Table 4]

[0078]

[Table 5]

[0079]

[Table 6]

[0080]

[Table 7]

[0081]

According to the present invention, there is provided a safety tire capable of stable running even if the tire is injured without sacrificing rolling resistance and riding comfort during normal running before the tire is damaged. Can be provided.

[Brief description of drawings]

FIG. 1 is a tire width direction sectional view showing a safety tire according to the present invention.

FIG. 2 is a sectional view in the tire width direction showing another safety tire according to the present invention.

[Explanation of symbols]

1 tire 2 rooms 3 rooms 4 complex 5 bead core 6 carcass 7 belt 8 treads 9 Inner liner layer 10 rims

Claims (13)

[Claims] 1. A safety system in which the inner space of a hollow donut-shaped tire is divided into a plurality of chambers, at least one of the plurality of chambers is filled with gas, and a composite having closed cells is arranged in the remaining at least one chamber. The tire has a cell content of 80.00% by volume to 98.75% by volume, and the internal pressure of the contained closed cells at 25 ° C. is 15 in absolute pressure.
A safety tire having a pressure of 0 kPa or higher and a continuous phase of the composite containing at least a nylon resin. 2. The safety tire according to claim 1, wherein the partition wall that divides the plurality of chambers is made of a rubber composition containing 50 mass% or more of butyl rubber. 3. The internal pressure at 25 ° C. of the closed cells in the composite according to claim 1 or 2, which is 200 in absolute pressure.
A safety tire having a kPa or higher. 4. The safety tire according to claim 1, 2 or 3, wherein the continuous phase of the composite is made of nylon resin and butyl rubber. 5. The safety tire according to claim 1, 2 or 3, wherein the continuous phase of the composite is made of a nylon resin. 6. The method according to any one of claims 1 to 5,
Nylon-based resins include nylon 6, nylon 11, nylon 12, nylon 6/66 copolymer and nylon 6 /
A safety tire comprising at least one selected from 12 copolymers. 7. The method according to any one of claims 1 to 6,
Nitrogen, air, carbon dioxide, carbon number 3 in the bubbles of the complex
No. 8 to 8 straight-chain and branched aliphatic hydrocarbons and at least one gas selected from the group consisting of alicyclic hydrocarbons having 3 to 8 carbon atoms. 8. The method according to claim 1, wherein
The continuous phase of the composite has a gas permeability coefficient of 30 at 30 ° C.
0 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg)
A safety tire characterized by being: 9. The method according to claim 1, wherein
The continuous phase of the composite has a gas permeability coefficient of 20 at 30 ° C.
× 10 ⁻¹² (cc · cm / cm ² · s · cmHg) or less, a safety tire. 10. The continuous phase of the composite according to claim 1, having a gas permeability coefficient of 2 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg) at 30 ° C.
A safety tire characterized by being: 11. The tire according to claim 1, further comprising an inner liner layer on an inner peripheral surface of the tire, the inner liner layer having a melting point of 170 to 230 ° C. and a nylon resin and isobutylene paramethylstyrene copolymer. The gelling rate of the elastomer component including the halide of 50 to
A safety tire comprising a thermoplastic elastomer composition dynamically vulcanized to 95%. 12. The inner liner layer according to claim 11, having a gas permeability coefficient of 20 × 10 at 30 ° C.
A safety tire having a pressure of ⁻¹² (cc · cm / cm ² · s · cmHg) or less. 13. A polymer containing at least a nylon resin, and at least one foaming agent selected from dinitrosopentamethylenetetramine, azodicarbonamide, paratoluenesulfonylhydrazine and its derivatives, and oxybisbenzenesulfonylhydrazine. A foamable composition containing: