JP2006159439A - Repairing method of punctured tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a repairing method for quickly certainly returning a tire of which the internal pressure is lowered upon the reception of an external damage to a runnable state. <P>SOLUTION: When the tire mounted on a vehicle through a rim receives a damage to lower the atmospheric pressure in its internal pressure, the tire air chamber demarcated by the tire and the rim, both of which are mounted on the vehicle, is filled with along with a gas while heating and expanding a large number of expansible resin particles encapsulating a gas component in a resin as a liquid state foaming agent to supply the expansible resin particles into the tire air chamber as hollow particles composed of a continuous phase due to the thermally expansible resin and closed cells not only to close the open wound by the hollow particles but also to apply use internal pressure by the filling with air. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a repair method for returning a tire that has been punctured due to trauma to a state in which it can run.

  In pneumatic tires, for example, passenger car tires, air is contained in the tire chamber under a pressure of about 150 kPa to 250 kPa as a gauge pressure, and tension is generated in the tire skeleton such as the carcass and belt of the tire. Therefore, the tire can be deformed and restored in response to the input to the tire. That is, by maintaining the internal pressure of the tire chamber within a predetermined range, a constant tension is generated in the tire skeleton to provide a load support function and increase the rigidity, driving, braking, turning performance, etc. The basic performance necessary for driving the vehicle is given.

  By the way, when the tire held at the predetermined internal pressure is damaged, high pressure air leaks to the outside through the external damage, and the tire internal pressure is reduced to the atmospheric pressure. Most of the tension that was generated in the process will be lost. As a result, the load support function and the driving, braking, and turning performance obtained by applying a predetermined internal pressure to the tire are also lost. As a result, the vehicle equipped with the tire cannot run.

Since the tire that has fallen into the puncture state needs to be repaired by filling the high-pressure gas after closing the wound that caused the puncture, remove the punctured tire from the vehicle and install the spare tire loaded on the vehicle. In general, puncture tires are transported to a repair site at a later date for repair.
Since dealing with punctures is complicated, it has been studied to repair tires while they are mounted on the vehicle at the time of occurrence of punctures. A typical method is a so-called puncture repair agent.

The technique using this puncture repair agent is a combination of an adhesive seal liquid and an electric pump that feeds compressed air, as described in Patent Document 1, for example. The liquid is supplied to the inside of the tire, the wound is closed with a sealing liquid, and air is filled to repair the damaged tire immediately.
International Publication No. 2004/048493 Pamphlet

  However, since the sealing liquid is a viscous material, it is difficult to reach the wound especially when the wound is above the tire. For example, it is necessary to perform preliminary traveling to rotate the tire after the sealing liquid is injected, or to rotate the tire. However, in order to replenish the air pressure leaked from the wound until the seal is completed, it is necessary to refill with air, or it takes a long time for the sealing liquid to reach the wound and seal it. There are disadvantages such as.

  In view of the above, an object of the present invention is to propose a repair method for reliably returning a tire whose internal pressure has decreased due to trauma to the tire to a running state in a short time.

  As a result of intensive studies to solve the above problems, the inventors can instantly close the wound that caused the puncture by utilizing hollow particles composed of a continuous phase and closed cells made of resin. As a result, the present invention has been completed.

That is, the gist configuration of the present invention is as follows.
(1) When a tire attached to a vehicle via a rim is damaged and the internal pressure is reduced to atmospheric pressure, a gas component is foamed in a liquid state in a tire chamber defined by the vehicle-attached tire and the rim. A large number of inflatable resin particles encapsulated in resin as an agent are filled with gas while being heated and expanded, and the expandable resin particles are filled into the tire chamber as hollow particles composed of a continuous phase and closed cells of a resin capable of thermal expansion. A method for repairing a puncture tire, characterized by supplying and closing a wound with the hollow particles and applying an internal pressure by gas filling.

(2) The method for repairing a puncture tire according to the above (1), wherein the expandable resin particles are heated and expanded 30 to 120 times.

(3) The method for repairing a puncture tire according to (1) or (2) above, wherein the expandable resin particles are heated at 60 to 300 ° C.

(4) The method for repairing a puncture tire according to any one of (1) to (3) above, wherein the filling rate of the hollow particles according to the following formula (I) is 1 vol% or more.
Filling ratio of hollow particles = (particle volume value / tire chamber volume value) × 100 --- (I)
here,
Particle volume value: The total volume of all the hollow particles placed in the tire chamber under the atmospheric pressure and the total void volume around the particles (cm ³ )
Tire chamber volume value: After filling the tire and rim assembly with air only and adjusting to the internal pressure (kPa), the amount of air discharged when the internal air is discharged until the internal pressure reaches atmospheric pressure (cm ³ ) using the following formula (II) (cm
³ )
Tire chamber volume value = (filled air discharge) / (internal pressure / atmospheric pressure) --- (II)
In the formula (II), the gauge pressure (kPa) is used for the internal pressure, and the absolute value (kPa) using a barometer is used for the atmospheric pressure value.

(5) The method for repairing a puncture tire according to (4) above, wherein the filling rate of the hollow particles is 5 vol% or more.

(6) The method for repairing a puncture tire according to (4) or (5) above, wherein the filling rate of the hollow particles is 10 vol% or more.

(7) The puncture tire repair according to any one of (1) to (6) above, wherein the hollow particles and gas obtained by heating and expanding the expandable resin particles are sent to a tire chamber through a compressor. Method.

(8) The method for repairing a puncture tire according to any one of (1) to (7) above, wherein a thermal expansion start temperature Ts1 of the expandable resin particles is 60 to 200 ° C.

(9) The method for repairing a puncture tire according to any one of (1) to (8) above, wherein a thermal expansion start temperature Ts1 of the expandable resin particles is 60 to 150 ° C.

(10) The puncture tire repair method according to any one of the above (1) to (9), wherein a thermal expansion start temperature Ts1 of the expandable resin particles is 60 to 120 ° C.

(11) The method for repairing a puncture tire according to any one of (1) to (10) above, wherein a thermal expansion start temperature Ts1 of the expandable resin particles is 60 to 100 ° C.

(12) The gas in the hollow part of the hollow particles is nitrogen, air, linear and branched aliphatic hydrocarbons having 2 to 8 carbon atoms and fluorinated products thereof, alicyclic hydrocarbons having 2 to 8 carbon atoms, and The fluorinated product and the following general formula (III):
R ¹ —O—R ² ---- (III)
(Wherein R ¹ and R ² are each independently a monovalent hydrocarbon group having 1 to 5 carbon atoms, and part of the hydrogen atoms of the hydrocarbon group may be replaced by fluorine atoms) The puncture tire repair method according to any one of (1) to (11) above, wherein the repair method is at least one selected from the group consisting of ether compounds represented by:

(13) The above-mentioned (1) to (1), wherein the resin constituting the expandable resin particles is at least one of a polyvinyl alcohol resin, an acrylonitrile polymer, an acrylic polymer, and a vinylidene chloride polymer. (12) The puncture tire repair method according to any one of the above.

(14) The resin constituting the expandable resin particles is composed of an acrylonitrile polymer, and the acrylonitrile polymer is an acrylonitrile polymer, an acrylonitrile / methacrylonitrile copolymer, an acrylonitrile / methyl methacrylate copolymer, or an acrylonitrile / methacrylonitrile. Any one of the above (1) to (13), which is at least one selected from the group consisting of: / methacrylate terpolymer and acrylonitrile / methacrylonitrile / methacrylic acid terpolymer How to repair puncture tires.

(15) In at least one of the steps before and after filling a large number of expandable resin particles with gas while heating, the expandable resin particles are introduced into the tire chamber without any heating step, and hollow in the tire chamber The method for repairing a puncture tire according to any one of (1) to (14), wherein the particles and the expandable resin particles are mixed.

(16) A large number of foams whose average bulk specific gravity under atmospheric pressure is larger than the average true specific gravity of the hollow particles are previously placed in the tire chamber, and filled while expanding and expanding the expandable resin particles after puncture. The puncture tire repair method according to any one of the above (1) to (15), wherein:

(17) In at least one of the steps before and after filling a large number of expandable resin particles with gas while heating, a large number of foams having an average bulk specific gravity under atmospheric pressure larger than the average true specific gravity of hollow particles The method for repairing a puncture tire according to any one of the above (1) to (15), wherein the puncture tire is added to a tire chamber and mixed with hollow particles.

(18) The foam has a substantially spherical shape with a diameter of 1 to 15 mm or a cubic shape with a side of 1 to 15 mm, an average bulk specific gravity of 0.06 to 0.3 (g / cc), and a closed cell. Alternatively, the method for repairing a puncture tire according to (16) or (17) above, wherein the puncture tire has a communication bubble.

  Here, the pressure of the tire chamber described in the text indicates a gauge pressure (pressure indicated on the gauge) unless otherwise specified.

  According to the present invention, the wound that caused the puncture is instantaneously closed by the hollow particles that are filled with the expandable resin particles and heated to expand the heated resin particles. It is possible to reliably return the tire whose internal pressure has been reduced to a state where it can run in a short time.

  Further, among the filled hollow particles, the hollow particles other than those used for sealing the wound remain in the tire chamber, and this remaining hollow particle functions to seal the wound at the time of another damage and to restore the lowered internal pressure. Therefore, a tire that has been repaired according to the present invention is a safety tire that can travel a certain distance without being disabled due to damage.

Below, the repair method of the puncture tire of this invention is demonstrated in detail with reference to FIG.
That is, when a puncture occurs in the tire 2 mounted on the vehicle via the rim 1, the expansion is performed by enclosing a gas component in a resin as a liquid foaming agent in a tire chamber defined by the tire 2 and the rim 1. Many of the conductive resin particles are filled while being heated together with a gas such as air or nitrogen.
Specifically, as shown in FIG. 1, first, a container 4 containing a expandable resin particle 3 and a compressor 5 for supplying gas, eg, air, to the container 4 via a hose 5a are used. The adapter 4b at the tip of the hose 4a extending from 4 is fixed to the tire valve 1a with screws. Next, when the stopper 4c between the container 4 and the hose 4a is opened, the expandable resin particles 3 and a part of the gas in the container 4 flow into the tire chamber.

  Here, it is important to provide a heater 40 in which a heating wire is wound around the hose 4a and the outside is covered with a heat insulating material, and the expandable resin particles 3 are guided into the tire chamber while being heated. That is, the expandable resin particles 3 are supplied to the tire chamber as hollow particles 30 composed of a continuous phase and closed cells made of a resin capable of thermal expansion by being heated and expanded in this heating process.

Next, the compressor 5 is operated to supply compressed air to the container 4. The air supplied into the container 4 is carried along with the remaining expandable resin particles 3 from the hose 4 a to the air chamber of the tire 2. Also in this process, the expandable resin particles 3 are heated by the heater 40 and are carried as hollow particles 30 into the tire chamber.
Thus, by supplying the hollow particles 30 into the tire chamber, the sealing of the wound and the supply of the internal pressure necessary for traveling are simultaneously achieved.

  The driving power for the compressor 5 and the power for the heater 40 are supplied from the vehicle by inserting the plug 5c at the end of the electric cable 5b into, for example, a cigar socket of the vehicle.

  The hollow particles 30 filled with the expandable resin particles 3 while being heated and supplied into the air chamber of the tire 2 have closed cells surrounded by a continuous phase of a substantially spherical resin, and have an average particle diameter. It is a hollow structure having a particle size distribution in the range of about 20 μm to 500 μm, or a spongy structure including a large number of small chambers due to closed cells. That is, the hollow particles 30 are particles that enclose closed closed cells that do not communicate with the outside, and the number of closed cells may be singular or plural. Here, “the inside of closed cells of a hollow particle group” is collectively referred to as “hollow part”. The hollow particles having closed cells indicate that the particles have a “resin shell” for enclosing the closed cells in a sealed state. Furthermore, the continuous phase by the above-mentioned resin refers to this “continuous phase on the component composition constituting the resin shell”. The composition of the resin shell is as described later.

  When the hollow particle group in which a large number of the hollow particles 30 are gathered is filled into the air chamber of the puncture tire together with air, for example, the air supplied at the same time leaks out of the tire through the wound from the tire air chamber. The wound is rushed into the air stream and sealed here. That is, the wound becomes a flow path through which the gas in the tire chamber leaks, and the flow path length substantially corresponds to the thickness of the tire. The hollow particles of the present invention can be clogged with a large number of hollow particles by the action of “consolidation” in the flow channel. Further, when the pressure in the tire chamber is increased from the atmospheric pressure, tension is applied to the tire frame, so that the inner diameter of the wound is reduced so as to be narrowed down. Therefore, the hollow particle group compacted to the wound can be sealed to the extent that the gas in the tire chamber is squeezed out by the pressure increase in the tire chamber and hardly leaks out. Therefore, the wound that caused the puncture can be instantly and reliably closed with the hollow particles.

Here, when the above-described hollow particles 30 are filled in the tire chamber and the wound is sealed, the filling rate of the hollow particles according to the following formula (I) is preferably set to 1 vol% or more.
Filling ratio of hollow particles = (particle volume value / tire chamber volume value) × 100 --- (I)
Here, the particle volume value, a total amount of the void volume of the total volume and particles surrounding at atmospheric pressure of all hollow particles arranged in the tire chamber (cm ^3), it can be calculated by the following method.

First, the average bulk specific gravity of the hollow particles under atmospheric pressure is determined. The method is calculated, for example, by measuring the weight of a known volume under atmospheric pressure. First, weigh the hollow particles in a graduated cylinder under atmospheric pressure, apply vibration in an ultrasonic water bath, and stabilize the packing between the hollow particles. And the total weight of the hollow particles is measured to calculate the average bulk specific gravity under atmospheric pressure. That is, the average bulk specific gravity of the hollow particles under atmospheric pressure is
Average bulk specific gravity of particles under atmospheric pressure = (total weight of particles) / (total volume of particles)
It is.

Next, measure the total weight of the hollow particles filled in the tire chamber, and calculate the "particle volume" placed inside the tire by dividing by the average bulk specific gravity of the hollow particles calculated above under atmospheric pressure. can do. That is,
Particle volume = (total weight of particles filled in tire) / (average bulk specific gravity of particles under atmospheric pressure)
It is.
In addition, particles having a desired particle volume can be arranged in the tire by a method of measuring particles in a container having a known volume and arranging the particles in the tire chamber.

The tire chamber volume value is adjusted to the working internal pressure (kPa) by filling the tire and rim assembly with only air, and then the filled air is discharged when the filled air is discharged to the atmospheric pressure. It is a value (cm ³ ) obtained from the following formula (II) using the amount (cm ³ ).
Tire chamber volume value = (filled air discharge) / (internal pressure / atmospheric pressure) --- (II)
In formula (II), the gauge pressure value (kPa) is used for the internal pressure, and the absolute value (kPa) measured by a barometer is used for the atmospheric pressure value. That is, the atmospheric pressure is represented by 0 [kPa] as a gauge pressure, but since the atmospheric pressure value itself fluctuates every day, the absolute value observed from the barometer at that time is used. Therefore, for example, when the atmospheric pressure at a certain time is 1013 hPa, 101.3 kPa is used as the absolute value of atmospheric pressure in the formula (II).

  The reason why the calculated filling ratio of the hollow particles is 1 vol% or more is as follows. In order to seal the wound, the concentration of the hollow particles with respect to the air when the hollow particles and the air are filled is important. That is, when the concentration is less than 1 vol%, the concentration of hollow particles in the mixture of hollow particles and air is so thin that the “consolidation” phenomenon does not easily occur in the wound, and the hollow particles may be ejected outside the tire chamber. is there. Therefore, in order to reliably seal the wound, it is necessary for the hollow particles to be present in an abundance ratio of a certain concentration or more with respect to air.

  Thus, if the wound is sealed, the internal pressure can be increased by the air to be filled, and the air is filled until the “use internal pressure” of the tire is reached. Here, “internal pressure” refers to “a tire chamber pressure value (gauge pressure value) for each mounting position specified by an automobile manufacturer for each vehicle”.

Now, the tire repaired according to the above includes hollow particles 30 that are not used for sealing wounds in the tire chamber 6, as shown in the cross section of the repaired tire assembled in the rim in FIG. Of course, the remaining hollow particles 30 exhibit the above-described function of sealing the wound even against re-puncture, but further, in the tire chamber without heating under a predetermined filling amount. When the introduced expandable resin particles are mixed with the hollow particles, it is possible to provide an internal pressure restoration function that copes with a decrease in internal pressure during puncture.
In FIG. 2, reference numeral 7 denotes a bead core, 8 denotes a carcass, 9 denotes a belt, 10 denotes a tread, and 11 denotes an inner liner.

  First, an effect at the time of re-puncture of a repaired tire in which the above expandable resin particles are mixed and filled in hollow particles will be described. Now, the tire after the repair is in a state where the pressure is increased by a compressor or the like and the running ability is temporarily recovered. From this state, when scratched again by nailing, etc., it is of course possible to seal a new wound with hollow particles, but at that time it is difficult to completely stop leakage of high-pressure gas in the tire It may become. In other words, as the number of flaws increases, the internal pressure holding ability of the tire will decrease, but in such low internal pressure traveling, the tire rolls while being greatly bent, so the air in the tire and the tire chamber is The temperature rises rapidly. At that time, as a result of heating the expandable resin particles mixed with the hollow particles, the expandable resin particles expand at a time when the expansion start temperature Ts1 is exceeded. By the expansion of the expandable resin particles, the gas in the tire chamber can be compressed, and the tire internal pressure that has started to be lost can be recovered again (expression of the internal pressure restoration function).

  As described above, in order to seal at least the damaged part, the filling rate of the hollow particles needs to be 1 vol% or more, and the temporary running ability can be recovered by increasing the pressure with a pump or the like thereafter. On the other hand, in order to reliably realize the running ability after re-scratching, it is necessary to further add the above expandable resin particles.

  Since hollow particles are particles with a low specific gravity and elasticity due to the hollow structure, when the tire is damaged and void gas around the hollow particles begins to leak from the damaged portion, the flow is caused by leakage of the void gas. It gets on the wounded part immediately after getting on, and the wound of the wounded part is instantly sealed. As described above, the function of sealing the damaged part by the hollow particles is an essential function that supports the internal pressure restoration function of the present invention.

As described above, in the tire and rim assembly filled with the hollow particles according to the present invention, the friction between the hollow particles is reduced due to the decrease in the tire chamber volume and the increase in the deflection of the tire due to the decrease in the internal pressure after the puncture. As a result, the internal pressure is restored due to the expansion of the expandable resin particles together with the rapid temperature rise of the particles, and safe driving after re-puncture can be realized.
The function according to the present invention is as described above. However, since the hollow particles are very bulky, there is a disadvantage of occupying a corresponding space when possessing the hollow particles necessary for expressing the function in advance. In that respect, in this invention, since it should just be possessed in the state of an expandable resin particle, there exists a merit which can reduce significantly the occupation space required for possession.

  Therefore, the inventors have intensively investigated the actual state of heat generation and expansion of the hollow particles, and found an appropriate range of the hollow particles. Now, the hollow particles are obtained by heating and expanding the “expandable resin particles” as the raw material, and the expandable resin particles have an expansion start temperature Ts1. Further, when the hollow particles obtained by the thermal expansion are heated again, the hollow particles start to expand further, and the expansion start temperature Ts2 of the hollow particles exists here. As a result of producing and examining hollow particles from many expandable resin particles, the inventors have determined Ts1, which is the expansion start temperature of the expandable resin particles that serve as a source of the function of restoring internal pressure in the present invention. It is used as an index of expansion characteristics.

First, the expansion behavior was observed when the expandable resin particles were heated and expanded. Since the expandable resin particles are in a stage before expansion, the particle diameter is extremely small as compared with the state of the hollow particles, and the thickness of the resin shell is extremely thick. Therefore, the microcapsule has a high rigidity. Therefore, even if the continuous phase of the resin shell exceeds the glass transition point in the process of thermal expansion, the expansion force of the internal gas overcomes the rigidity of the shell until the shell is softened to some extent by further heating. I can't. Therefore, Ts1 shows a higher value than the actual glass point transfer of the shell.
On the other hand, when the hollow particles are heated and expanded again, the thickness of the shell of the hollow particles is extremely thin and the rigidity as the hollow body is low. Therefore, since the continuous phase of the shell exceeds the glass transition point in the process of thermal expansion, expansion starts at the same time, so Ts2 is positioned lower than Ts1.

Here, it is important that Ts1 of the expandable resin particles is 60 ° C. or more and 200 ° C. or less. This is because if the Ts1 of the expandable resin particles is less than 60 ° C., the temperature at which the container containing the expandable resin particles is stored in the vehicle may be taken into account in this storage environment.
On the other hand, when the temperature exceeds 200 ° C., even if the temperature rises due to frictional heat generation of the hollow particles in the run flat running after puncture damage, the expansion start temperature Ts1 of the added expandable resin particles cannot be reached. In some cases, the intended “internal pressure restoration function” cannot be fully developed.

  Therefore, the range of Ts1 of the expandable resin particles is 60 ° C. or more and 200 ° C. or less, preferably 150 ° C. or less, more preferably 120 ° C. or less, and most preferably 100 ° C. or less.

  As described above, by arranging the mixture of the expandable resin particles having the expansion start temperature Ts1 according to the above upper limit value and the lower limit value and the hollow particles obtained therefrom, it is possible to reliably exhibit the internal pressure restoration function. Of course, the “internal pressure restoration function maintenance” in regular use is achieved.

  In order to exhibit this function of restoring the internal pressure, it is important to mix the expandable resin particles with the hollow particles in the tire chamber as described above. In this case, the mixing ratio of the expandable resin particles is preferably in the range of 5 vol% to 100 vol% of the hollow particle volume. This is because if it is less than 5 vol%, the effect of adding expandable resin particles may not be clearly obtained. On the other hand, if it is 100 vol% or more, the endothermic amount of the expandable resin particles is too large, so the speed of the internal pressure recovery may become slow, and as a result, the tire side part is running with the road surface in contact with the road surface. There is a concern that the tire itself, which is a pressure vessel, may break down due to the length of time that is spent.

Next, as the gas constituting the hollow part (closed cell) of the hollow particle, nitrogen, air, linear and branched aliphatic hydrocarbons having 2 to 8 carbon atoms and fluorinated products thereof, carbon numbers 2 to 8 are used. And fluorinated products thereof, and the following general formula (III):
R ¹ —O—R ² ---- (III)
(Wherein R ¹ and R ² are each independently a monovalent hydrocarbon group having 1 to 5 carbon atoms, and part of the hydrogen atoms of the hydrocarbon group may be replaced by fluorine atoms) And at least one selected from the group consisting of ether compounds. The gas filled into the tire chamber may be air. However, when the gas in the particles is not a fluorinated product, a gas not containing oxygen, such as nitrogen or an inert gas, is preferable from the viewpoint of safety.

  The method for obtaining hollow particles having closed cells is not particularly limited, but a general method is to produce “expandable resin particles” using a foaming agent and to heat and expand them. Examples of the foaming agent include a method utilizing vapor pressure such as high-pressure compressed gas and liquefied gas, and a method utilizing a thermally decomposable foaming agent that generates gas by thermal decomposition.

  Many of the latter thermally decomposable foaming agents are characterized by generating nitrogen, and the particles obtained by appropriately controlling the reaction of the expandable resin particles obtained by foaming by these have mainly nitrogen in the bubbles. It will be a thing. Although it does not specifically limit as this thermally decomposable foaming agent, Dinitroso pentamethylenetetramine, azodicarbonamide, para-toluene sulfonyl hydrazine and its derivative (s), and oxybisbenzene sulfonyl hydrazine can be mentioned suitably.

Next, a technique for obtaining “expandable resin particles” that become hollow particles by utilizing the vapor pressure of the former high-pressure compressed gas and liquefied gas will be described.
When polymerizing the continuous phase of the resin forming the hollow particles, linear and branched aliphatic hydrocarbons having 2 to 8 carbon atoms and fluorinated products thereof, alicyclic hydrocarbons having 2 to 8 carbon atoms and Fluorides and the following general formula (III):
R ¹ —O—R ² ---- (III)
(Wherein R ¹ and R ² are each independently a monovalent hydrocarbon group having 1 to 5 carbon atoms, and part of the hydrogen atoms of the hydrocarbon group may be replaced by fluorine atoms) In this method, at least one selected from the group consisting of ether compounds represented by the following formula is liquefied under high pressure as a blowing agent and dispersed in a reaction solvent, followed by emulsion polymerization. As a result, it is possible to obtain “expandable resin particles” in which the gas components shown above are contained in a liquid state foaming agent in the resin continuous phase of the previous operation, and by heating and expanding this, desired hollow particles are obtained. I can get it.

  Further, the surface of the “expandable resin particles” is coated with an anti-blocking agent such as silica particles, carbon black fine powder, antistatic agent, surfactant, oil agent, etc. Can be obtained.

  In addition, in order to give the necessary minimum internal pressure by the hollow particles in a state where the tire chamber pressure is reduced due to damage, in addition to the addition of the expandable resin particles, a gas sealed at a predetermined pressure in the hollow part of the hollow particles It is important that the resin does not leak to the outside of the particles, in other words, the continuous phase of the resin corresponding to the shell portion of the hollow particles has a property that it is difficult for gas to permeate. That is, the resin constituting the continuous phase is made of a material having low gas permeability, specifically, it is made of at least one of acrylonitrile copolymer, acrylic copolymer, and vinylidene chloride copolymer. Is essential. These materials are particularly effective in the present invention because they have flexibility as hollow particles with respect to input due to tire deformation.

  In particular, it is preferable to apply any one of an acrylonitrile polymer, an acrylic polymer, and a vinylidene chloride polymer to the continuous phase of the hollow particles. More specifically, the polymer constituting the polymer is a polymer selected from acrylonitrile, methacrylonitrile, methyl methacrylate, methacrylic acid, and vinylidene chloride, preferably acrylonitrile / methacrylonitrile / methyl methacrylate terpolymer, acrylonitrile. At least one selected from the group consisting of / methacrylonitrile / methacrylic acid terpolymer is advantageously suitable. Since all of these materials have a small gas permeability coefficient and are difficult for gas to permeate, the gas in the hollow part of the hollow particles hardly leaks to the outside, and the pressure in the hollow part can be appropriately maintained.

Further, the continuous phase of the hollow particles has a gas permeability coefficient at 30 ° C. of 300 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg) or less, preferably a gas permeability coefficient at 30 ° C. of 20 × 10 ⁻¹² ( ^{cc · cm / cm 2 · s} · cmHg) or less, it is recommended and further preferably the gas permeability coefficient at 30 ° C. is ^{2 × 10 -12 (cc · cm} / cm 2 · s · cmHg) or less. This is because normal performance gas permeability coefficient of the inner liner layer in the pneumatic tire of ^{300 × 10 -12 (cc · cm} / cm 2 · s · cmHg) In the following levels have sufficient internal pressure retaining function In view of the above, the gas permeation coefficient at 30 ° C. was set to 300 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg) or less for the continuous phase of the particles. However, at this gas permeation coefficient level, it is necessary to replenish the internal pressure once every 3 to 6 months. From the standpoint of maintainability, 20 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg) or less, more preferably 2 × 10 ⁻¹² (cc · cm / cm ² · s · cmHg) or less is recommended.

  Here, in filling the tire air chamber with the hollow particles according to the present invention, in order to enhance the sealing function of the tire damage portion when the tire is damaged, the average bulk specific gravity is previously set in the tire air chamber in the average true value of the hollow particles. A large number of foams larger than the specific gravity are arranged and filled with the expandable resin particles heated and expanded after puncture, or in addition to filling the expandable resin particles with heat expansion, immediately before or immediately after the filling. It is effective to arrange the foam in at least one of the steps. Specifically, it has a substantially spherical shape with a diameter of 1 to 15 mm or a cubic shape with one side of 1 to 15 mm, has independent or open cells, has an average bulk specific gravity of 0.06 to 0.3 g / cc, and particles By adding a large number of foams having a bulk specific gravity value larger than the average true specific gravity of the hollow particles alone, it becomes possible to seal large wounds that are difficult to seal with the hollow particles alone, and the manifestation of the internal pressure restoration function It is possible to extend the period and increase the running ability after tire damage.

  That is, since the hollow particles have a substantially spherical shape, the fluidity is high, so that the hollow particles can be easily arranged from the inlet having a small inner diameter such as a tire valve into the tire chamber. On the other hand, after the tire has been damaged, air is supplied by a compressor or the like while heating and filling the inflatable resin particles, and then the hollow particles are blown from the damaged portion to the outside of the tire together with the high-pressure gas in the tire chamber. It will gather on the inside of the club. However, since the wound path from the inner surface of the scratched part to the outer peripheral surface of the tire is not a straight line but presents a complicated and complicated shape, the particles entering from the wound on the inner surface of the tire are obstructed on the way of the path, resulting in a large number of hollow particles. Will gather in a compressed state on the inner surface of the damaged part, and the damaged part is temporarily sealed. Here, provisionally sealing refers to a state in which the hollow particles themselves do not leak, but the void gas around the particles gradually leaks.

At that time, if the size of the scratch on the damaged part is extremely large, provisional sealing with only the particles may be incomplete, and the hollow particles may leak out of the tire. In such a case, the sealing level can be improved as follows by adding a large number of the above-mentioned foams.
First, if a large number of the above-mentioned foams are arranged in the tire chamber in advance, along with the leakage of the gas in the tire chamber due to puncture, the foam adheres to the inner surface of the wound and accompanies the pressure and rotation in the tire chamber. Due to the centrifugal force, it enters a state where it is further submerged inside the wound. When the hollow particles are filled by the subsequent repair, the wound in which the foam has entered is sealed, and an extremely reliable sealing state can be obtained.

  On the other hand, in the tire after repair, a centrifugal force corresponding to the speed is generated in the tire chamber during rolling, and the foam having a large bulk specific gravity under the centrifugal force is directed to the inner liner side of the tire. The hollow particles having a small true specific gravity are unevenly distributed closer to the rotation center than the foam. In this state, even if a scratch of a size that cannot be sealed only with the particles is received again, the foam is unevenly distributed near the inner liner surface of the tire inner surface. It is extremely effective to seal the damaged part by quickly coming into close contact with the inner surface of the wound part of the damaged part in an attempt to blow out the tire.

  In particular, when the foam is a foam having open cells, it has high compressibility, easily adheres to the shape of the wound, and easily enters into the inside of the wound. This makes it possible to change the gas flow path of the complicated and refined gas into a state most suitable for sealing with the hollow particles, which is a very effective means.

Moreover, it is preferable to have a tire valve used in combination with hollow particles and gas filling. The tire valve includes a filter that blocks hollow particles in the tire chamber and allows only gas to pass outside the tire chamber. By attaching such a tire valve, when repairing a punctured tire according to the present invention, it becomes possible to place hollow particles in the tire chamber with only one valve, so there is only one valve hole. No general-purpose rim can be used as it is. In addition, it is possible to prevent “leakage of hollow particles during gas replenishment work” against a natural drop in tire chamber pressure during running after repair, and to easily maintain the tire chamber pressure.
As such a tire valve, one having the structure illustrated in FIG. 3 can be used. Here, the code | symbol 12 is the said filter, For example, a nonwoven fabric can be used.

The expandable resin particles shown in Table 1 and the following sealing liquid were prepared as fillers for repairing the puncture tires, and the puncture tires were repaired by filling them according to the conditions shown in Table 1. Table 1 also shows the results of investigations on the sealing performance of wounds in each repair and the running ability after re-puncture.
DPNR latex (rubber solid content): 500 parts by mass (300 parts by mass)
Tackifier: 200 masses Ethylene glycol: 300 masses Water-soluble polymer 2.5% CMC aq. (CMC solid content): 30 parts by mass (0.75 parts by mass)

Using an assembly with a tire size of 245 / 45R18 and a rim size of 7.5J-18, it was mounted on a passenger car with a displacement of 3000 cc, and a 6 mmφ nail was stepped and damaged under an internal pressure of 200 kPa.
Next, under the heating conditions shown in Table 1, each tire chamber was filled with the expandable resin particles as hollow particles using a compressor. Further, each tire air chamber was filled with the sealing liquid to be compared under the filling rate shown in Table 1. Table 3 shows the results of measurement of the average particle size, average true specific gravity, and expansion ratio in the tire chamber of the hollow particle group supplied to the tire chamber while heating and expanding the expandable resin particles shown in Table 2. .

  Here, the sealing performance of the wound is that the tire chamber is filled with a predetermined amount of sealing liquid or hollow particles, filled with air at a flow rate of 20 l / min until the internal pressure becomes 200 kPa, and then traveled for 10 km at a speed of 50 km / h. The tire internal pressure after the comparison was compared. As the tire internal pressure is kept at 200 kPa, the flaw sealability is better. In addition, the position of the damaged part when filling the sealing liquid or the hollow particles is (1) 0 ° (within the ground contact surface), (2) 90 ° (position 90 ° apart from the 0 ° position), (3) 180 It was carried out at 3 levels (° opposite to the tire shaft on the ground contact surface).

  Moreover, the running ability after re-puncturing is that the tire is filled with internal pressure and left at 60 km / h for 500 km and left for 24 hours, and then a 6 mmφ nail is stepped on at a position different from the first damage. The position of the damaged part was (3) 180 ° and left for 3 days. Thereafter, the vehicle was run at 60 km / h, and the running ability after re-puncturing was examined.

It should be noted that the air chamber pressure of each tire is adjusted to 200 kPa, which is the working internal pressure, in a state where no load is applied, and high pressure air in the air chamber is discharged to determine the amount of gas discharged, and the air chamber volume of each tire Was calculated. The calculation results are shown in Table 1.
Here, the measurement of the air volume of the tire was performed according to the following procedure.
[Measurement method of tire chamber volume]
Step 1: while maintaining the state in which that no load is the assembly of the tire and rim, filled with air at room temperature, a predetermined pressure (using pressure) is adjusted to P _2. In this case, the tire's air chamber volume of interest in P ₂ under and V _2.
Procedure 2: The tire valve is opened, and the air in the tire chamber is discharged to the atmospheric pressure P ₁ while flowing into the integrating flow meter, and the charged air discharge amount V ₁ is measured. As the integrating flow meter, DC DRY gas meter DC-2C, intelligent counter SSF manufactured by Shinagawa Seiki Co., Ltd. was used.
Using the above measured values,
Tire chamber volume value = (filled air discharge) / (internal pressure / atmospheric pressure) --- (II)
Accordingly, the tire chamber volume V ₂ at the use internal pressure P ₂ can be obtained.
In the formula (II), the internal pressure used was a gauge pressure value (kPa), and the atmospheric pressure value was an absolute value (kPa) measured by a barometer.

Furthermore, the method for measuring the average true specific gravity of the hollow particles is as follows.
[Measurement method of average true specific gravity]
The average true specific gravity value of the particles is generally measured by a liquid replacement method (Archimedes method), which is an ordinary method using isopropanol, and this ordinary method is also used in the present invention.

Moreover, the measuring method of the average particle diameter and particle size distribution of expansive resin particles and hollow particles is as follows.
Instrument: Sympatec Gmbh Laser Diffraction Particle Size Analyzer HELOS & RODOS System Measurement conditions: 2S-100ms / DRY
Dispersion pressure: 2.00 bar, feed: 50.00%, rotation: 60.00%
Shape factor: 1.00
Measurement is performed under the above conditions, and the following measured values are adopted.
That is, the volume-based average particle size is set as the average particle size value (D50 value) of the present invention.
Moreover, the expansion ratio was calculated | required with the following formula | equation.
Expansion ratio = (average particle diameter of hollow particles / average particle diameter of expandable resin particles) ³

Furthermore, the measuring method of the thermal expansion start temperature Ts1 of each expandable resin particle and the reexpansion start temperature Ts2 of each hollow particle is as follows.
[Measurement method of thermal expansion start temperature of particles]
The thermal expansion start temperature Ts1 in Table 2 was determined by measuring the expansion displacement amount under the following conditions, and setting it as the temperature at the rise of the displacement amount.
Equipment: PERKIN-ELMER 7Series
“Thermal Analysis System”
Measurement conditions: temperature increase rate 10 km / min, measurement start temperature 25 ° C., measurement end temperature 220 ° C.
Measurement physical quantity: Measures the amount of expansion displacement due to heating.

  In addition, on the inner surface of the rim of the assembly of the tire and rim to be evaluated, a pressure sensor that monitors the tire chamber pressure is incorporated, and the signal of the measured pressure data is transmitted by radio using a commonly used telemeter, The vehicle was run while measuring changes in pressure by receiving it with a receiver installed inside the test vehicle. In the run after the second injury (re-puncture), it is assumed that re-repair is not possible, and without any additional filling of sealing liquid or hollow particles and re-replenishment of air, Carried out from the state. In this situation, the mileage of 20 km or more was accepted as a premise, assuming direct access to the repair shop.

  From the results shown in Table 1, it can be seen that the seal liquid increases in viscosity when it is exposed to air after repair, and therefore it is difficult to seal the wound when punctured again. Further, if the vehicle is parked after repair, the sealing liquid collects on the inner surface of the ground surface, and it is difficult for the entire roll to become familiar with the entire roll. Therefore, it is difficult to seal the wound when it is damaged again. Usually, since only one sealing liquid is mounted, sealing after re-puncture is difficult, and even if it is refilled with air, it will be removed immediately, so the running ability is extremely low after the second damage.

On the other hand, as shown in Invention Examples 1 to 3, since the hollow particles are excellent in mobility in the tire, the sealing properties are high, and the internal pressure after traveling 10 km is kept high.
Further, as shown in Invention Examples 4 to 6, if the amount of the expandable resin particles added is 5 vol% or more with respect to the hollow particles, the vehicle can travel a certain distance by the expression of the internal pressure restoration mechanism even without replenishing air. it can.

It is a figure which shows the repair point of a puncture tire. It is tire width direction sectional drawing after the repair according to this invention. It is a figure which shows an example of the "valve for tires provided with the filter" used together with the filling of a hollow particle and gas mounted in the assembly of the tire and rim after the repair according to this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rim 2 Tire 3 Expandable resin particle 4 Container 5 Compressor 6 Tire air chamber 7 Bead core 8 Carcass 9 Belt 10 Tread 11 Inner liner layer 12 Filter 30 Hollow particle 40 Heater

Claims (18)

When a tire attached to a vehicle via a rim is damaged and the internal pressure is reduced to atmospheric pressure, a gas component is used as a liquid foaming agent in a tire air chamber partitioned by the vehicle-mounted tire and the rim. A large number of inflatable resin particles contained in the container are filled with gas while being heated and expanded, and the inflatable resin particles are supplied into the tire chamber as hollow particles composed of a continuous phase and closed cells by a resin capable of thermal expansion, A method for repairing a puncture tire, wherein a wound is closed with the hollow particles, and an internal pressure is applied by gas filling. The puncture tire repair method according to claim 1, wherein the expandable resin particles are heated and expanded 30 to 120 times. The method for repairing a puncture tire according to claim 1 or 2, wherein the expandable resin particles are heated at 60 to 300 ° C. The puncture tire repair method according to any one of claims 1 to 3, wherein a filling rate of the hollow particles according to the following formula (I) is 1 vol% or more.
Filling ratio of hollow particles = (particle volume value / tire chamber volume value) × 100 --- (I)
here,
Particle volume value: The total volume of all the hollow particles placed in the tire chamber under the atmospheric pressure and the total void volume around the particles (cm ³ )
Tire chamber volume value: After filling the tire and rim assembly with air only and adjusting to the internal pressure (kPa), the amount of air discharged when the internal air is discharged until the internal pressure reaches atmospheric pressure (cm ³ ) using the following formula (II) (cm
³ )
Tire chamber volume value = (filled air discharge) / (internal pressure / atmospheric pressure) --- (II)
In the formula (II), the gauge pressure (kPa) is used for the internal pressure, and the absolute value (kPa) using a barometer is used for the atmospheric pressure value. The puncture tire repair method according to claim 4, wherein a filling ratio of the hollow particles is 5 vol% or more. The puncture tire repair method according to claim 4 or 5, wherein a filling rate of the hollow particles is 10 vol% or more. The puncture tire repair method according to any one of claims 1 to 6, wherein the hollow particles and gas obtained by heating and expanding the expandable resin particles are sent to a tire chamber through a compressor. The puncture tire repair method according to any one of claims 1 to 7, wherein a thermal expansion start temperature Ts1 of the expandable resin particles is 60 to 200 ° C. The puncture tire repair method according to any one of claims 1 to 8, wherein a thermal expansion start temperature Ts1 of the expandable resin particles is 60 to 150 ° C. The puncture tire repair method according to any one of claims 1 to 9, wherein a thermal expansion start temperature Ts1 of the expandable resin particles is 60 to 120 ° C. The puncture tire repair method according to any one of claims 1 to 10, wherein a thermal expansion start temperature Ts1 of the expandable resin particles is 60 to 100 ° C. The gas in the hollow part of the hollow particles is nitrogen, air, linear and branched aliphatic hydrocarbons having 2 to 8 carbon atoms and fluorinated products thereof, alicyclic hydrocarbons having 2 to 8 carbon atoms and fluorinated products thereof. And the following general formula (III):
R ¹ —O—R ² ---- (III)
(Wherein R ¹ and R ² are each independently a monovalent hydrocarbon group having 1 to 5 carbon atoms, and part of the hydrogen atoms of the hydrocarbon group may be replaced by fluorine atoms) The puncture tire repair method according to claim 1, wherein the repair method is at least one selected from the group consisting of ether compounds represented by: The resin constituting the expandable resin particles is composed of at least one of a polyvinyl alcohol resin, an acrylonitrile-based polymer, an acrylic polymer, and a vinylidene chloride-based polymer. Repair method for puncture tires described in 1. The resin constituting the expandable resin particles is composed of an acrylonitrile polymer, and the acrylonitrile polymer is an acrylonitrile polymer, an acrylonitrile / methacrylonitrile copolymer, an acrylonitrile / methyl methacrylate copolymer, or an acrylonitrile / methacrylonitrile / methyl methacrylate. The puncture tire repair method according to any one of claims 1 to 13, which is at least one selected from a terpolymer and an acrylonitrile / methacrylonitrile / methacrylic acid terpolymer. . In at least one of the steps before and after filling a large number of the expandable resin particles with the gas, the heating step is omitted and the expandable resin particles are introduced into the tire chamber and expanded with the hollow particles in the tire chamber. The puncture tire repair method according to any one of claims 1 to 14, wherein the resin particle is mixed. In the tire chamber, a large number of foams whose average bulk specific gravity under atmospheric pressure is larger than the average true specific gravity of the hollow particles are arranged in advance, and the expansion resin particles are filled while being heated and expanded after puncturing. The puncture tire repair method according to any one of claims 1 to 15. At least one of the steps before and after filling a large number of expandable resin particles with gas while heating, a large number of foams having an average bulk specific gravity under atmospheric pressure larger than the average true specific gravity of hollow particles The puncture tire repair method according to any one of claims 1 to 15, wherein the puncture tire repair method according to any one of claims 1 to 15, wherein the puncture tire is added to a room and mixed with hollow particles. The foam has a substantially spherical shape with a diameter of 1 to 15 mm or a cubic shape with a side of 1 to 15 mm, an average bulk specific gravity of 0.06 to 0.3 (g / cc), and closed cells or open cells. The puncture tire repair method according to claim 16 or 17, characterized by comprising:

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