JP2003118311A - Safety tire, composite body used in the same, and foamable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety tire capable of realizing stable running even if the tire is damaged without sacrificing rolling resistance and riding comfortableness in ordinary running before the tire is damaged. SOLUTION: An inner space of the hollow doughnut-like tire is divided into a plurality of chambers, at least one chamber among the plurality of chambers is filled with gas, and a composite body composed of continuous phases of resin and independent air bubbles is arranged in at least one remaining chamber. Air bubble content of the composite body is set to 80.00 to 98.75 vol.%, and an internal pressure at 25 deg.C of incorporated air bubbles is set 150 kPa or more by absolute pressure.

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, internal pressure (absolute pressure, the same applies hereinafter) 2
Air is trapped under about 50 to 350 kPa to generate tension 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 traveling at a relatively high speed and a long distance, a core or the like is attached to the rim. Run-flat tires having a structure in which the internal support of is fixed to support the load at the time of puncture are 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. Since the idle wheel is a wheel that cannot roll itself, that is, cannot generate a driving force, 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. And since the foaming ratio of any of the composites is low, the composite having bubbles has a large weight, and it is inevitable that vibration riding comfort and fuel consumption are deteriorated, and since the inside of the closed cells is at atmospheric pressure,
It was not functionally sufficient as a substitute for 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 it 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, repeated deformation during rolling of the tire causes the foam to generate heat, 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 a passenger car tire 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 that the vulcanization pressure is insufficient and blown out. 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 blowing agent is to increase the blending amount of the blowing agent so that the internal pressure at room temperature is 400%.
Since it greatly exceeds KPa, it has been difficult to substitute for a conventional pneumatic tire. 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. Further, although the exhaust small hole formed in the rim is effective for naturally exhausting the normal pressure air inside the tire due to the expansion of the inflation pressure bubble, it does not function as a dissipation path for the gas in the bubble in the inflation pressure bubble. Therefore, it cannot withstand long-term use.

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 goes without saying that it becomes a factor in the occurrence of peeling of the soft elastic envelope coating. 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 the tire is damaged without sacrificing rolling resistance and riding comfort during normal running.

[0017]

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 the remaining at least one chamber is composed of a continuous phase and closed cells made of resin. A composite tire having the following composition, wherein the composite has a cell content of 80.00% by volume to 98.75% by volume, and 2
A safety tire characterized in that the internal pressure at 5 ° C is 150 kPa or more in absolute pressure.

(2) A safety tire according to the above (1), characterized in that the partition walls for partitioning the plurality of chambers are made of a rubber composition containing 50 mass% or more of butyl rubber. In a safety tire in which a composite consisting of a resin continuous phase and closed cells is arranged inside a hollow donut-shaped tire, the composite cell content is 80.00% by volume to 98.75% by volume, In addition, the safety tire is characterized in that the internal pressure at 25 ° C of the built-in closed cells is 150 kPa or more in absolute pressure.

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

(4) In any one of the above (1) to (3), the continuous phase of the composite is made of at least one of a resin having a polar functional group in the molecule and a polyolefin resin. And safety tires.

(5) In the above (4), the resin having a polar functional group in the molecule is a polyvinyl alcohol resin, an acrylonitrile copolymer, an acrylic copolymer, a vinylidene chloride copolymer, an acrylonitrile / styrene resin. And a safety tire comprising at least one of a polyester resin.

(6) A safety tire according to the above (4), wherein the polyolefin resin is at least one of polyethylene resin, polypropylene resin and polystyrene / polyethylene copolymer.

(7) A safety tire according to any one of (1) to (5) above, wherein the continuous phase of the composite is a polyvinyl alcohol resin.

(8) In any one of the above (1) to (5), the continuous phase of the composite comprises an acrylonitrile polymer, and the acrylonitrile polymer is an acrylonitrile polymer or an acrylonitrile / methacrylonitrile copolymer. A safety tire comprising at least one selected from acrylonitrile / methyl methacrylate copolymer and acrylonitrile / methacrylonitrile / methyl methacrylate terpolymer.

(9) In any one of (1) to (5) above, the continuous phase of the composite is an acrylic polymer, and the acrylic polymer is a methyl methacrylate resin or a methyl methacrylate / acrylonitrile copolymer. , Methylmethacrylate / methacrylonitrile copolymer and methylmethacrylate / acrylonitrile /
A safety tire comprising at least one selected from a methacrylonitrile terpolymer.

(10) In any one of the above (1) to (5), the continuous phase of the composite is a vinylidene chloride polymer, and the vinylidene chloride polymer is a vinylidene chloride / acrylonitrile copolymer or chloride. Vinylidene / methylmethacrylate copolymer, vinylidene chloride / methacrylonitrile copolymer, vinylidene chloride / acrylonitrile / methacrylonitrile copolymer, vinylidene chloride / acrylonitrile / methylmethacrylate copolymer,
A safety tire comprising at least one selected from vinylidene chloride / methacrylonitrile / methyl methacrylate copolymer and vinylidene chloride / acrylonitrile / methacrylonitrile / methyl methacrylate copolymer.

(11) In any one of the above (1) to (10), nitrogen, air, linear and branched aliphatic hydrocarbons having 3 to 8 carbon atoms and carbon are contained in the bubbles of the composite. A safety tire comprising at least one gas selected from the group consisting of alicyclic hydrocarbons represented by formulas 3 to 8.

(12) In any one of the above (1) to (11), the continuous phase of the composite has a gas permeability coefficient of 300 × 10 ⁻¹² (cc · cm / cm ² · s · s) at 30 ° C.
cmHg) or less, a safety tire.

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

(14) In any one of the above (1) to (13), the continuous phase of the composite has a gas permeation coefficient at 30 ° C. of 2 × 10 ⁻¹² (cc · cm / cm ² · s · cm).
Hg) or less, a safety tire.

(15) In any one of (1) to (14) above, an inner liner layer is provided on the inner peripheral surface of the tire, and the inner liner layer has a melting point of 170 to 230 ° C.
A safety tire comprising a thermoplastic elastomer composition, which is obtained by dynamically vulcanizing an elastomer component to a gelation rate of 50 to 95%, containing the nylon resin of 1. and a halide of isobutylene paramethylstyrene copolymer.

(16) In the above (15), the gas permeability coefficient of the inner liner layer at 30 ° C. is 20 × 10.
^-12 (cc · cm / cm ² · s · cmHg) or less, a safety tire.

[0034]

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 thereof. 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.

Here, the composite body 4 has closed cells in which individual cells are isolated by being surrounded by partition walls.
The bubble content rate in the composite 4 is from 80.00% by volume to 9%.
8.75% by volume and 25 ° C. of the closed cells contained therein
The internal pressure at 150 kPa in absolute pressure, preferably 20
It is important to set it to 0 kPa or more. 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.
In addition, when the bubble content exceeds 98.75% by volume, the degree of damage to the composite due to tire damage increases and the rate of propagation thereof also increases, and in this case also the durability of the composite against repeated deformation is increased. Markedly reduced.

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

Similarly, if the internal pressure of the closed cells at 25 ° C. is less than 150 kPa, the flexure of the composite increases and the amount of repeated deformation during tire rolling increases, so that fatigue of the composite during normal running before tire damage occurs. In addition to increasing the history, the rate of progress of damage to the composite due to tire trauma increases with an increase in the amount of deformation, and in this case as well, the durability of the composite against repeated deformation significantly decreases, and The performance when driving is insufficient.

Here, in the safety tire of FIG. 1, as a device for maximizing the durability of the composite body, the chamber 2 is filled with 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 disposed inside is characterized in that even if the tire is damaged, the tension of the case does not easily decrease like 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 does not lose tension as a case due to partial damage of the composite body 4. Also, the conventional pneumatic tire does not fall into a flat state.
Further, the probability of damage to the composite 4 due to the external damage of the tire is extremely low, and even if damaged, the area thereof is extremely limited.
It cannot be deteriorated enough to impair tire function.

Moreover, the pressure in the vicinity of the damaged closed bubbles is reduced to the atmospheric pressure, but the closed bubbles around the damaged bubbles are 150 kP.
Since it has an internal pressure of a or more, 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, so that so-called self-repair becomes possible.

The above state is a state in which the composite directly or indirectly bears the 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.

When 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 obviously larger 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.

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 bubbles 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 of hardly permeating gas. That is, the continuous phase of the composite body 4 serving as the matrix of the closed cells is made of a material having low gas permeability, specifically,
Polyvinyl alcohol resin, acrylonitrile-based copolymer, acrylic-based copolymer, vinylidene chloride-based copolymer,
It is essential that it is composed of at least one of acrylonitrile / styrene resin (AS), polyethylene resin (PE), polypropylene resin (PP), polyester resin (PET) and polystyrene / polyethylene copolymer (PS / PE). is there. All of these materials are particularly effective for the present invention because they can be foamed relatively easily in the tire and have flexibility for input due to tire deformation.

In particular, it is preferable to apply any one of polyvinyl alcohol resin, acrylonitrile polymer, acrylic polymer and vinylidene chloride polymer to the continuous phase of the composite. Further, as the acrylonitrile-based polymer, at least one selected from acrylonitrile polymer, acrylonitrile / methacrylonitrile copolymer, acrylonitrile / methyl methacrylate copolymer and acrylonitrile / methacrylonitrile / methyl methacrylate terpolymer, acrylic Methyl methacrylate resin (MM
A), methyl methacrylate / acrylonitrile copolymer (MMA / AN), methyl methacrylate / methacrylonitrile copolymer (MMA / MAN) and methyl methacrylate / acrylonitrile / methacrylonitrile terpolymer (MMA / AN / MAN) At least one selected from the following, and as vinylidene chloride-based polymer, vinylidene chloride / acrylonitrile copolymer, vinylidene chloride / methyl methacrylate copolymer, vinylidene chloride / methacrylonitrile copolymer, vinylidene chloride / acrylonitrile / methacrylonitrile Copolymer, vinylidene chloride / acrylonitrile / methyl methacrylate copolymer, vinylidene chloride / methacrylonitrile / methyl methacrylate copolymer, vinylidene chloride / acrylonitri / Methacrylonitrile / at least one selected from methyl methacrylate copolymer advantageously compatible respectively. 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. .

Next, the continuous phase of the composite has a gas permeability coefficient of 300 × 10 ⁻¹² (cc · cm / cm ^{2) at} 30 ° C.
· S · cmHg) or less, preferably a gas permeability coefficient at 30 ° C. of 20 × 10 ⁻¹² (cc · cm / cm ² · s · c)
mHg) or less, more preferably a gas permeability coefficient at 30 ° C. of 2 × 10 ⁻¹² (cc · cm / cm ² · s · cmH)
It is recommended that g) or less. Because, the gas permeability coefficient of the inner liner layer in a normal pneumatic tire is 300 × 10 ⁻¹² (cc · cm / cm ² · s · cm).
Considering the track record of having a sufficient internal pressure holding function at the level of Hg) or less, the continuous phase of the composite also has a temperature of 30 ° C.
300 gas permeability at × 10 ^{-1 2} (cc · cm
/ Cm ² · s · cmHg) or less. However, at this gas permeation coefficient level, it is necessary to replenish the internal pressure about once every 3 to 6 months, so from the viewpoint of maintainability, it is 20 × 10 ^-12. (Cc · cm / cm ² ・ S ・ cmH
g) or less, more preferably 2 × 10 ⁻¹² (cc · cm)
/ Cm ² · s · cmHg) or less is recommended.

As the gas forming the closed cells of the composite, nitrogen, air, a linear or branched aliphatic hydrocarbon group having 3 to 8 carbon atoms and an alicyclic group having 3 to 8 carbon atoms are used. At least one selected from the group consisting of hydrocarbon groups can be mentioned.

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.

The safety tire of the present invention is characterized in that the internal pressure of the closed cells of the composite disposed inside is higher than the atmospheric pressure, and in order to realize such a safety tire, Much depends on the following 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 during the manufacturing process and control the generation and growth of bubbles while appropriately adjusting.

The first method is to load a predetermined amount of the foamable composition into a tire, mount the tire on a rim, and then heat the tire assembly 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.

In the third method, for example, as in Expancel (trademark), polymer hollow particles in which butane, propane, pentane, etc. are liquefied and sealed are injected into the tire assembly after the rim assembly. Then, the tire assembly is heated to foam the inside of 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 where the material which becomes the continuous phase of the composite is melted and the fluidity appears. Is injected with to form a composite inside the tire assembly.

A fifth method is to charge a foamed composition molded into an annular shape inside a tire, install the tire in a rim, and then heat the tire assembly.
Foaming is performed inside the tire. The expandable polymer composition does not necessarily have to be annular, but from the viewpoint of workability and uniform filling, it is preferably annular.

The sixth method is to melt a resin continuous phase forming a composite by liquefying and encapsulating butane, propane, pentane and the like in high molecular hollow particles such as Expancel under the trade name. A tire and a rim assembly are filled with the product, and then the tire assembly is heated as necessary to foam the inside of the tire.

A seventh method is, for example, hollow particles of polymer, such as Expancel, which are liquefied and encapsulated in polymer hollow particles such as butane, propane or pentane, and are heat-foamed in advance to form substantially spherical hollow beads. This is compression packed into the tire and rim assembly.

When the chamber 3 is filled with the composite body by the above-mentioned method, after the partition walls for partitioning the plurality of chambers have been mounted in the tire assembly in advance, a gas having a volume equal to or larger than the tire internal 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.

The continuous phase includes polyvinyl alcohol resin, acrylonitrile polymer, acrylic polymer,
At least one resin selected from vinylidene chloride-based polymer, acrylonitrile / styrene resin, polyethylene resin, polypropylene resin, polyester resin and polystyrene / polyethylene copolymer is suitable, and dinitroso is used as the thermally decomposable foaming agent. At least one selected from pentamethylenetetramine (DPT), azodicarbonamide (ADCA), p-toluenesulfonylhydrazine (TSH) and its derivatives, and oxybisbenzenesulfonylhydrazine (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 ratio means the pelletized mixture after biaxial kneading is Soxhlet extracted with acetone for 8 hours in a water bath, 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

[0067] Further, the inner liner layer, the gas permeability coefficient at 30 ° C. is ^{20 × 10 -1 2 (cc ·} cm / c
It is preferably m ² · s · cmHg) or less. 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 of 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 mode 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%. This is because the use of a nylon resin as the continuous phase results in extremely low gas permeability, so that the function as a tube can be enhanced. Further, by using a thermoplastic elastomer composition in which an elastomer component containing a halide of an isobutylene paramethylstyrene copolymer is dynamically vulcanized to a gelation rate of 50 to 95%, it is rich in flexibility, heat resistance and durability. A partition wall having excellent properties can be obtained.

Also in this partition, the gas permeation 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

[0071]

EXAMPLES Composites of various specifications shown in Tables 1 and 2 were applied to a tire having the structure shown in FIG. .5J ×
A prototype safety tire for passenger cars of size 185 / 70R14 built into 14 rims was manufactured. Here, the tire 1 complies with a general structure of the tire type and size.
The types of resin of the composite continuous phase in Tables 1 and 2 are as shown in Table 3.

The expansion start temperature in Tables 1 and 2 is the temperature at the rise of the displacement measured by measuring the expansion displacement under the following conditions. Equipment: Nishizawa PERKIN-ELMER 7 Series
(Thermal Analysis System) Measurement conditions: temperature rising rate 10 ° C./min, measurement start temperature 25
℃, measurement end temperature 200 ℃, measurement physical quantity: measure expansion displacement due to heating

The bubble internal pressures shown in Tables 1 and 2 were calculated based on the following equation (A). Bubble pressure (kP
a) = [(Wt / ρs) / Vt] 101.325 ----
(A) Here, Wt: weight of the complex filled in the tire chamber Vt: internal volume of the chamber used for filling ρs: specific gravity of the complex sampled from the tire under atmospheric pressure, ρs = Ws / Vs, where Vs: volume of the composite sampled from the tire under atmospheric pressure Ws: weight of the composite sampled from the tire

For each of the tires thus obtained, the riding comfort and rolling resistance during normal use were investigated. That is, as for the riding comfort, a trial tire was mounted on a 2000 cc class passenger car, a feeling test concerning riding comfort was conducted by two professional drivers, an evaluation was performed on a maximum of 10 points, and the average thereof was obtained. The larger this value, the better the riding comfort.

The rolling resistance was measured by the coasting method, and the tire internal pressure (absolute internal pressure): 270 kPa, the load: JIS 100% load, and the coasting start temperature: 100.
The test was carried out under the condition of km, and the work amount corresponding to the rolling resistance of the tire was obtained from the speed decreasing curve of the coasting drum. The measurement result is 100 for the result of the tire of Comparative Example 1.
It was shown as an index. The smaller this number is,
It shows that the rolling resistance is small.

Further, each tire was mounted on a passenger car of 2000 cc class, and then the tire had a diameter of 3 mm and a length of:
After injuring a 3 cm nail from the outside of the tire tread through the tread, apply a load equivalent to that of 4 people and run the test course at 90 km / h for a maximum of 500 km. The travelable distance was measured. The results of these investigations are also shown in Tables 1 and 2.

[0077]

[Table 1]

[0078]

[Table 2]

[0079]

[Table 3]

[0080]

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

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Claims (16)

[Claims] 1. An 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 the remaining at least one chamber is made of a resin continuous phase and closed cells. A safety tire having a composite arranged therein, wherein the composite has a bubble content of 80.00% by volume to 9%.
8.75% by volume and 25 ° C. of the closed cells contained therein
A safety tire having an internal pressure of 150 kPa or more in absolute pressure. 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 safety tire according to claim 1 or 2, wherein the internal pressure of the contained closed cells at 25 ° C. is 200 kPa or more in absolute pressure. 4. The method according to any one of claims 1 to 3,
The safety tire, wherein the continuous phase of the composite is made of at least one of a resin having a polar functional group in the molecule and a polyolefin resin. 5. The resin having a polar functional group in the molecule according to claim 4, which is any one of polyvinyl alcohol resin, acrylonitrile polymer, acrylic polymer, vinylidene chloride polymer, acrylonitrile / styrene resin and polyester resin. Or a safety tire comprising at least one kind. 6. The safety tire according to claim 4, wherein the polyolefin resin is at least one selected from a polyethylene resin, a polypropylene resin and a polystyrene / polyethylene copolymer. 7. The method according to any one of claims 1 to 5,
A safety tire in which the continuous phase of the composite is made of polyvinyl alcohol resin. 8. The method according to any one of claims 1 to 5,
The continuous phase of the composite consists of an acrylonitrile-based polymer,
The acrylonitrile-based polymer is at least one selected from acrylonitrile polymer, acrylonitrile / methacrylonitrile copolymer, acrylonitrile / methyl methacrylate copolymer and acrylonitrile / methacrylonitrile / methyl methacrylate terpolymer. A featured safety tire. 9. The method according to claim 1, wherein
The continuous phase of the composite is made of an acrylic polymer, and the acrylic polymer is a methylmethacrylate resin, a methylmethacrylate / acrylonitrile copolymer, a methylmethacrylate / methacrylonitrile copolymer and a methylmethacrylate / acrylonitrile / methacrylonitrile ternary. A safety tire comprising at least one selected from copolymers. 10. The composite phase according to claim 1, wherein the continuous phase of the composite is a vinylidene chloride polymer, and the vinylidene chloride polymer is a vinylidene chloride / acrylonitrile copolymer or vinylidene chloride / methyl methacrylate. Copolymer, vinylidene chloride / methacrylonitrile copolymer, vinylidene chloride / acrylonitrile /
At least one selected from methacrylonitrile copolymer, vinylidene chloride / acrylonitrile / methyl methacrylate copolymer, vinylidene chloride / methacrylonitrile / methyl methacrylate copolymer, vinylidene chloride / acrylonitrile / methacrylonitrile / methyl methacrylate copolymer Safety tires characterized by being present. 11. The compound according to claim 1, wherein nitrogen, air, a linear or branched aliphatic hydrocarbon having 3 to 8 carbon atoms and a carbon atom having 3 to 8 carbon atoms are contained in the bubbles of the composite. A safety tire comprising at least one gas selected from the group consisting of alicyclic hydrocarbons. 12. The continuous phase of the composite according to claim 1, which has a gas permeability coefficient of 300 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg) at 30 ° C.
A safety tire characterized by being: 13. The continuous phase of the composite according to claim 1, wherein the gas permeation coefficient at 30 ° C. is 20 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg) or less. Safety tires characterized by. 14. The composite phase according to claim 1, wherein the continuous phase of the composite has a gas permeability coefficient at 30 ° C. of 2 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg) or less. Safety tires characterized by. 15. 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 an 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%. 16. The gas permeation coefficient at 30 ° C. of the inner liner layer according to claim 15, which is 20 × 10.
^-12 (cc · cm / cm ² · s · cmHg) or less, a safety tire.