JP2019006006A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire excellent in initial sealing performance, sealing performance after driving and sealing performance at low temperature.SOLUTION: A pneumatic tire 10 has a sealant layer 22 inside the inner liner 19 in the radial direction of the tire. The sealant layer 22 has a structure including a first sealant layer 22a and a second sealant layer 22b laminated in this order from the inner liner 19 side. The viscosity of the first sealant layer 22a is lower than the viscosity of the second sealant layer 22b. The second sealant layer 22B is thicker than the first sealant layer 22A. Each of the sealant layers has a thickness of 1 to 5 mm, and the total thickness of the layers is 7 mm or less.SELECTED DRAWING: Figure 11

Description

The present invention relates to a pneumatic tire.

As a pneumatic tire having a puncture prevention function (hereinafter, a pneumatic tire is also simply referred to as a tire), a sealant tire in which a sealant material is applied to an inner peripheral surface of the tire is known. In a sealant tire, a hole formed at the time of puncture is automatically closed by a sealant material.

As a method for producing a sealant tire, an organic solvent is added to the sealant material, a diluted sealant material that reduces viscosity and is easy to handle is applied to the inner surface of the tire, and the organic solvent is removed from the diluted sealant material after application. Known is a method (for example, Patent Document 1), which is prepared by mixing a main agent and a curing agent prepared by a type kneading apparatus using a static mixer or a dynamic mixer to prepare a sealant material and then sticking the sealant material to the inner peripheral surface of the tire. It has been.

In recent years, a sealant tire using a sealant material obtained by oxidizing and crosslinking butyl rubber and liquid rubber has been put into practical use. In this sealant tire, it is possible to prevent puncture caused by foreign matter up to φ5 mm in an environment of −20 ° C. to 80 ° C. As the temperature changes, the viscosity of the sealant also changes, so each company is investigating a method to maintain an appropriate viscosity in the temperature range to be used so that it does not flow too much at high temperatures while ensuring fluidity at low temperatures. .

Special table 2010-528131

As a result of intensive studies by the present inventors, the following has been found.
In the conventional technology, when a puncture-causing foreign object (for example, a nail having a diameter of 5 mm and a length of 60 mm) is stuck in the tread portion of the tire, a puncture-causing foreign object is caused by the expansion of a hole caused by the puncture-causing foreign object. May fall off the tire (the nail that has been pierced will come off). In this case, the sealant material may flow out of the hole and lose the internal pressure. In addition, even when the puncture-causing foreign matter did not fall off the tire (the stuck nail did not come off) during driving, the sealant was removed when the puncture-causing foreign matter was removed artificially (with the nail removed) after running. The material may flow out of the hole and lose internal pressure.
In this way, with the conventional technology, good sealing performance (initial sealing performance) is exhibited when the puncture-causing foreign object is stuck, but when the puncture-causing foreign object is stuck and the hole is widened, The internal pressure may be lost when the puncture-causing foreign matter is removed inside or when the puncture-causing foreign matter is artificially removed after running.
That is, when the puncture-causing foreign object is pierced and the hole is widened, there are cases where good sealing performance (sealing performance after traveling) cannot be obtained after removing the puncture-causing foreign substance.

Further, when a high-viscosity sealant material is used, relatively good sealing performance can be obtained even with a large hole, but there is room for improvement in that the sealing performance at low temperatures is sacrificed.

An object of the present invention is to solve the above problems and to provide a pneumatic tire excellent in initial sealing performance, sealing performance after traveling, and sealing performance at low temperatures.

The present invention is a pneumatic tire having a sealant layer on the inner side in the tire radial direction of the inner liner, wherein the sealant layer is formed by laminating a first sealant layer and a second sealant layer in this order from the inner liner side. And the viscosity of the first sealant layer is lower than the viscosity of the second sealant layer.

The second sealant layer is preferably thicker than the first sealant layer.

The first sealant layer and the second sealant layer preferably have a thickness of 1 to 5 mm.

The total thickness of the first sealant layer and the second sealant layer is preferably 7 mm or less.

The first sealant layer contains 200 parts by mass or more of liquid polybutene, 40 parts by mass or less of carbon black, and 15 parts by mass or less of a crosslinking agent with respect to 100 parts by mass of the rubber component, and the 0 ° C. viscosity is 35 kPa · The second sealant layer is composed of a liquid polybutene having a viscosity of 250 parts by mass or less, 40 parts by mass or more of carbon black with respect to 100 parts by mass of the rubber component. It is preferably composed of a sealant material containing 15 parts by mass or more of the agent, having a 0 ° C. viscosity of 35 kPa · s or more and a 95 ° C. viscosity of 6 kPa · s or more.

The present invention is a pneumatic tire having a sealant layer on the inner side in the tire radial direction of the inner liner, wherein the sealant layer is formed by laminating a first sealant layer and a second sealant layer in this order from the inner liner side. And the first sealant layer has a lower viscosity than the second sealant layer, so that the initial seal performance, the seal performance after traveling, and the seal performance at low temperature are improved. Excellent.

It is explanatory drawing which shows typically an example of the coating device used with the manufacturing method of a sealant tire. It is an enlarged view near the front-end | tip of the nozzle which comprises the coating device shown in FIG. It is explanatory drawing which shows typically the positional relationship of the nozzle with respect to a tire. It is explanatory drawing which shows typically an example of the state by which the substantially string-like sealant material was continuously affixed helically on the inner peripheral surface of the tire. It is an enlarged view near the front-end | tip of the nozzle which comprises the coating device shown in FIG. It is explanatory drawing which shows typically an example of the sealant material currently affixed on the sealant tire. It is explanatory drawing which shows typically an example of the manufacturing equipment used for the manufacturing method of a sealant tire. It is explanatory drawing which shows typically an example of the cross section of the sealant material at the time of cut | disconnecting the sealant material of FIG. 4 by the straight line AA orthogonal to the application direction (length direction) of a sealant material. It is explanatory drawing which shows an example of the cross section of a pneumatic tire typically. It is a graph which shows the outline of an example of the result of having measured the steady flow shear viscosity of the sealant material. It is explanatory drawing which shows typically an example of a 1st sealant layer and a 2nd sealant layer. It is explanatory drawing which shows typically the behavior of a 1st sealant layer and a 2nd sealant layer when a tire is punctured with a nail.

The present invention is a pneumatic tire having a sealant layer on the inner side in the tire radial direction of the inner liner, wherein the sealant layer is formed by laminating a first sealant layer and a second sealant layer in this order from the inner liner side. And the viscosity of the first sealant layer is lower than the viscosity of the second sealant layer.

Generally, in a sealant tire having a sealant layer on the inner surface for preventing puncture, the sealing performance is
1) Sealing performance when a foreign object such as a nail gets stuck during traveling.
2) The rubber around the part where the foreign object has been punctured due to the foreign object's stagnation or heating during traveling with the foreign object pierced, and the hole formed by the foreign object spreads out. Sealing performance when foreign matter comes out of the tire due to centrifugal force.
3) After traveling with a foreign object stuck, the hole formed by the foreign object expands, the air gradually leaks from the tire, the internal pressure decreases, and the internal pressure alarm device is activated and the driver notices a puncture , Sealing performance when the driver removes foreign matter.
4) Sealing performance when the atmosphere of 3) is extremely low temperature.
There are 4 types.

Conventional sealant tires usually satisfy 1) sealing performance (initial sealing performance), but 2) and 3) sealing performance (sealing performance after running) is not sufficient. The sealing performance of 2) and 3) can be ensured by using a relatively high viscosity sealant material. However, the high viscosity sealant material becomes too viscous at low temperatures, and the seal of 4). It was difficult to achieve both performance (sealing performance at low temperature).

In contrast, in the present invention, the sealant layer disposed on the inner radial direction of the inner liner is a laminated structure of a low-viscosity first sealant layer and a high-viscosity second sealant layer. By placing one sealant layer on the tire cavity side (the inside of the first sealant layer in the radial direction of the tire), the second sealant layer has a high viscosity for large holes and has a low viscosity at low temperatures. It can be sealed with a first sealant layer. As a result, it is possible to achieve both the seal performance after running and the seal performance at a low temperature, which were difficult with conventional sealant tires, and a good initial seal performance can be obtained.

In addition, the sealant tire of the present invention can be sealed with the high-viscosity second sealant layer in the summer when the temperature is high, and with the low-viscosity first sealant layer in the winter when the temperature is low. It is also possible to achieve both the sealing performance at the same time.

FIG. 11 is an explanatory view schematically showing an example of the first sealant layer and the second sealant layer, and FIG. 12 schematically shows the behavior of the first sealant layer and the second sealant layer when the tire is punctured by a nail. FIG. As shown in FIGS. 11 and 12, the sealant layer 22 has a configuration in which a first sealant layer 22 a and a second sealant layer 22 b are laminated in this order from the inner liner 19 side of the tire 10. Then, as shown in FIG. 12A, after the nail A is pierced into the tire 10 and the nail A is removed, the hole formed by the nail A is sealed by the sealant layer 22. When the temperature is high or when the hole is large, as shown in FIG. 12B, the high-viscosity second sealant layer 22b mainly seals, and when the temperature is low or the hole is small, FIG. As shown in FIG. 2, the first sealant layer 22a having a low viscosity mainly seals. In this way, while ensuring good initial sealing performance, it is possible to achieve both the sealing performance after driving and the sealing performance at low temperature, and the compatibility between the sealing performance in summer and the sealing performance in winter. it can.

In addition, the sealant layer should just be comprised by 2 layers, the 1st sealant layer and the 2nd sealant layer, and the other layer may be further arrange | positioned in the range which does not inhibit the effect of this invention.

Further, in the present invention, a sealant layer is formed by continuously applying a substantially string-like sealant material to the inner peripheral surface of the tire in a spiral manner, so that the sealant material has a uniform sealant layer (the inner periphery of the tire). A sealant layer made up of a substantially string-like sealant material arranged in a spiral along the surface can be formed on the inner peripheral surface of the tire, and a sealant tire with excellent sealing performance can be stably produced. Can be manufactured well. The sealant tire obtained by the production method is excellent in sealability because the sealant material has a uniform sealant layer in the tire circumferential direction and the tire width direction (particularly in the tire circumferential direction). In addition, the balance of the tire is less likely to be lost due to the sealant material, and deterioration of tire uniformity can be reduced.

In particular, by using a sealant material having the composition described later as the sealant material, the effect can be obtained more suitably. Furthermore, in the sealant material having the composition described later, the hole formed at the time of puncture is automatically closed by the sealant material even under a low temperature environment.

As a sealant material having the composition described later, specifically, a sealant material is obtained by using an organic peroxide as a cross-linking agent, or by using a rubber component containing a butyl rubber and a liquid polymer such as liquid polybutene. The adhesiveness, sealability, fluidity, and processability of the resin are improved in a well-balanced manner, and the effect is more suitably obtained. This is because a liquid polymer component is introduced into an organic peroxide cross-linking system using a butyl rubber as a rubber component, and adhesion is imparted. In particular, liquid polymers having different viscosities are used at high speeds (at high temperatures). It is estimated that the performance of the sealant material is improved in a well-balanced manner by suppressing the flow of the sealant material. Furthermore, by blending 1 to 30 parts by mass of the inorganic filler with respect to 100 parts by mass of the rubber component, the adhesiveness, sealability, fluidity and processability of the sealant material are improved in a more balanced manner, and the effect is more suitably can get.

Hereinafter, the suitable example of the manufacturing method of the sealant tire of this invention is demonstrated.

For example, the sealant tire is prepared by mixing each component constituting the sealant material to prepare a sealant material, and then applying the obtained sealant material to the tire inner peripheral surface by coating or the like to form a sealant layer. Can be manufactured. The sealant tire has a sealant layer on the inner side in the tire radial direction of the inner liner.

It is necessary to control the viscosity of the sealant material according to the operating temperature by controlling the hardness (viscosity) according to the rubber component and the amount of crosslinking. Therefore, the type and amount of liquid rubber, plasticizer, and carbon black are adjusted as a rubber component control. On the other hand, in order to control the amount of crosslinking, the type and amount of the crosslinking agent and crosslinking aid are adjusted. In this way, the viscosity of the first sealant layer and the second sealant layer can be easily adjusted.

As a sealant material, if it has adhesiveness, it will not specifically limit, The normal rubber composition used for the puncture seal of a tire can be used. A butyl rubber is used as a rubber component constituting the main component of the rubber composition. Examples of the butyl rubber include halogenated butyl rubber (X-IIR) such as brominated butyl rubber (Br-IIR) and chlorinated butyl rubber (Cl-IIR) in addition to butyl rubber (IIR). Among these, from the viewpoint of fluidity and the like, either one or both of butyl rubber and halogenated butyl rubber can be preferably used. Moreover, it is preferable to use the pelletized butyl rubber. Thereby, a butyl rubber can be supplied to a continuous kneader accurately and suitably, and a sealant material can be produced with high productivity.

As a butyl rubber, a butyl rubber having a Mooney viscosity ML1 + 8 at 125 ° C. of 20 or more and less than 40 and / or a Mooney viscosity ML1 + 8 at 125 ° C. of 40 or more and 80 or less from the viewpoint of suppressing a decrease in fluidity of the sealant material. The use of rubber B is preferable, and at least butyl rubber A is preferably used. In addition, what is necessary is just to set a compounding ratio suitably, when using butyl-type rubber A and B together.

The Mooney viscosity ML1 + 8 at 125 ° C. of the butyl rubber A is more preferably 25 or more, further preferably 28 or more, more preferably 38 or less, still more preferably 35 or less. If it is less than 20, the fluidity may be lowered, and if it is 40 or more, the effect may not be obtained when used in combination.

The Mooney viscosity ML1 + 8 at 125 ° C. of the butyl rubber B is more preferably 45 or more, still more preferably 48 or more, more preferably 70 or less, still more preferably 60 or less. If it is less than 40, the effect may not be obtained when used in combination. When it exceeds 80, there exists a possibility that a sealing performance may fall.

The Mooney viscosity ML1 + 8 at 125 ° C. is based on JIS K-6300-1: 2001, the test temperature is 125 ° C., the rotor having an L-shape is preheated for 1 minute, and the rotor rotation time is 8 minutes. It is to be measured.

As rubber components, natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR) Other components such as diene rubber such as acrylonitrile butadiene rubber (NBR) and butyl rubber (IIR) may be used in combination, but from the viewpoint of fluidity, the content of butyl rubber in 100% by mass of the rubber component Is preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 100% by mass.

As liquid polymer in the sealant material, liquid polybutene, liquid polyisobutene, liquid polyisoprene, liquid polybutadiene, liquid poly α-olefin, liquid isobutylene, liquid ethylene α-olefin copolymer, liquid ethylene propylene copolymer, liquid ethylene butylene copolymer A polymer etc. are mentioned. Of these, liquid polybutene is preferable from the viewpoint of imparting tackiness and the like. Examples of the liquid polybutene include copolymers having a long-chain hydrocarbon molecular structure mainly composed of isobutene and further reacted with normal butene, and hydrogenated liquid polybutene can also be used.

As a liquid polymer such as liquid polybutene, from the viewpoint of preventing the flow of the sealant material at high speed, the liquid polymer A having a kinematic viscosity at 100 ° C. of 550 to 625 mm ² / s and / or the kinematic viscosity at 100 ° C. of 3540 to 4010 mm ^{The use of 2} / s of liquid polymer B is preferred, and the combined use of liquid polymers A and B is more preferred.

The kinematic viscosity at 100 ° C. of the liquid polymer A such as liquid polybutene is preferably 550 mm ² / s or more, more preferably 570 mm ² / s or more. If it is less than 550 mm ² / s, the sealant material may flow. The kinematic viscosity at 100 ° C. is preferably 625 mm ² / s or less, more preferably 610 mm ² / s or less. If it exceeds 625 mm ² / s, the viscosity of the sealant material increases, and the extrudability may deteriorate.

The kinematic viscosity at 100 ° C. of the liquid polymer B such as liquid polybutene is preferably 3600 mm ² / s or more, more preferably 3650 mm ² / s or more. If it is less than 3540 mm ² / s, the viscosity of the sealant material is too low, and it tends to flow during use of the tire, which may deteriorate the sealing performance and uniformity.
The kinematic viscosity at 100 ° C. is preferably 3900 mm ² / s or less, more preferably 3800 mm ² / s or less. If it exceeds 4010 mm ² / s, the sealing property may be deteriorated.

Kinematic viscosity at 40 ° C. of liquid polymer A, such as liquid polybutene is preferably 20000 mm ² / s or more, more preferably 23000mm ² / s or more. If it is less than 20000 mm ² / s, the sealant material may be soft and flow may occur. The kinematic viscosity at 40 ° C. is preferably 30000 mm ² / s or less, more preferably 28000 mm ² / s or less. If it exceeds 30000 mm ² / s, the viscosity of the sealant material becomes too high, and the sealing performance may be deteriorated.

The kinematic viscosity at 40 ° C. of the liquid polymer B such as liquid polybutene is preferably 120,000 mm ² / s or more, more preferably 150,000 mm ² / s or more. If it is less than 120,000 mm ² / s, the viscosity of the sealant material is too low, and the sealant material tends to flow during use of the tire, and the sealing performance and uniformity may be deteriorated.
The kinematic viscosity at 40 ° C. is preferably 200000 mm ² / s or less, more preferably 170000 mm ² / s or less. If it exceeds 200,000 mm ² / s, the viscosity of the sealant material becomes too high, and the sealing performance may be deteriorated.

In addition, kinematic viscosity is a value measured on condition of 100 degreeC and 40 degreeC based on JISK2283-2000.

In the case of the sealant material used for the first sealant layer, the content of the liquid polymer (total amount of the liquid polymers A, B, etc.) is preferably 200 parts by mass or more, and 230 parts by mass or more with respect to 100 parts by mass of the rubber component. Is more preferable. An upper limit is not specifically limited, What is necessary is just about 300 mass parts or less. Moreover, in the case of the sealant material used for the second sealant layer, 250 parts by mass or less is preferable with respect to 100 parts by mass of the rubber component, and 220 parts by mass or less is more preferable. A minimum is not specifically limited, What is necessary is just about 150 mass parts or more. If it is in the said range, an effect will be acquired more suitably.

When liquid polymers A and B are used in combination, the blending ratio (content of liquid polymer A / content of liquid polymer B) is preferably 10/90 to 90/10, more preferably 30/70 to 70 /. 30, more preferably 40/60 to 60/40. Within the above range, good tackiness is imparted.

It does not specifically limit as an organic peroxide (crosslinking agent), A conventionally well-known compound can be used. By using a butyl rubber or liquid polymer in the organic peroxide crosslinking system, adhesiveness, sealing properties, fluidity, and processability are improved.

Examples of the organic peroxide include acyl peroxides such as benzoyl peroxide, dibenzoyl peroxide, and p-chlorobenzoyl peroxide, 1-butyl peroxyacetate, t-butyl peroxybenzoate, and t-butyl peroxy. Peroxyesters such as phthalate, ketone peroxides such as methyl ethyl ketone peroxide, alkyl peroxides such as di-t-butylperoxybenzoate, 1,3-bis (1-butylperoxyisopropyl) benzene, t- Hydroperoxides such as butyl hydroperoxide, dicumyl peroxide, t-butyl cumyl peroxide and the like can be mentioned. Of these, acyl peroxides are preferable from the viewpoint of tackiness and fluidity, and dibenzoyl peroxide is particularly preferable. Moreover, it is preferable to use the organic peroxide (crosslinking agent) in a powder state. Thereby, an organic peroxide (crosslinking agent) can be accurately and suitably supplied to a continuous kneader, and a sealant material can be produced with high productivity.

In the case of the sealant material used for the first sealant layer, the content of the organic peroxide (crosslinking agent) is preferably 15 parts by mass or less and more preferably 12 parts by mass or less with respect to 100 parts by mass of the rubber component. A minimum is not specifically limited, What is necessary is just about 5 mass parts or more. Moreover, in the case of the sealant material used for a 2nd sealant layer, 15 mass parts or more are preferable with respect to 100 mass parts of rubber components, and 18 mass parts or more are more preferable. An upper limit is not specifically limited, What is necessary is just about 25 mass parts or less. If it is in the said range, an effect will be acquired more suitably.

As crosslinking aids (vulcanization accelerators), sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamine, aldehyde-amine, aldehyde-ammonia, imidazoline, xanthogenic acid, And at least one selected from the group consisting of quinone dioxime compounds (quinoid compounds) can be used, and for example, quinone dioxime compounds (quinoid compounds) can be suitably used. By using a butyl rubber or liquid polymer in a crosslinking system in which a crosslinking aid is further added to the organic peroxide, the tackiness, sealing property, fluidity, and processability are improved.

Examples of the quinone dioxime compound include p-benzoquinone dioxime, p-quinone dioxime, p-quinone dioxime diacetate, p-quinone dioxime dicaproate, p-quinone dioxime dilaurate, and p-quinone dioxime distea. Rate, p-quinone dioxime dicrotonate, p-quinone dioxime dinaphthenate, p-quinone dioxime succinate, p-quinone dioxime adipate, p-quinone dioxime difuroate, p-quinone Quinone dioxime dibenzoate, p-quinone dioxime di (o-chlorobenzoate), p-quinone dioxime di (p-chlorobenzoate), p-quinone dioxime di (p-vitrobenzoate), p-quinone dioxime Di (m-vitrobenzoate), p-quinonedio Shimdi (3,5-dinitrobenzoate), p-quinonedioximdi (p-methoxybenzoate), p-quinonedioximdi (n-amyloxybenzoate), p-quinonedioximdi (m-bromobenzoate), etc. Is mentioned. Of these, p-benzoquinonedioxime is preferable from the viewpoints of tackiness, sealing properties, and fluidity. Further, it is preferable to use a crosslinking aid (vulcanization accelerator) in a powder state. Thereby, a crosslinking aid (vulcanization accelerator) can be suitably and accurately supplied to a continuous kneader, and a sealant material can be produced with high productivity.

In the case of the sealant material used for the first sealant layer, the content of the crosslinking aid such as a quinonedioxime compound is preferably 15 parts by mass or less, and more preferably 12 parts by mass or less with respect to 100 parts by mass of the rubber component. A minimum is not specifically limited, What is necessary is just about 5 mass parts or more. Moreover, in the case of the sealant material used for a 2nd sealant layer, 15 mass parts or more are preferable with respect to 100 mass parts of rubber components, and 18 mass parts or more are more preferable. An upper limit is not specifically limited, What is necessary is just about 25 mass parts or less. If it is in the said range, an effect will be acquired more suitably.

Sealant materials include carbon black, silica, calcium carbonate, calcium silicate, magnesium oxide, aluminum oxide, barium sulfate, talc, mica and other inorganic fillers, aromatic process oils, naphthenic process oils, paraffinic process oils A plasticizer such as the above may be added.

In the case of the sealant material used for the first sealant layer, the content of the inorganic filler is preferably 40 parts by mass or less and more preferably 30 parts by mass or less with respect to 100 parts by mass of the rubber component. A minimum is not specifically limited, What is necessary is just about 10 mass parts or more. Moreover, in the case of the sealant material used for a 2nd sealant layer, 40 mass parts or more are preferable with respect to 100 mass parts of rubber components, and 45 mass parts or more are more preferable. An upper limit is not specifically limited, What is necessary is just about 65 mass parts or less. If it is in the said range, an effect will be acquired more suitably.

From the viewpoint of preventing deterioration due to ultraviolet rays, carbon black is preferred as the inorganic filler. In the case of the sealant material used for the first sealant layer, the carbon black content is preferably 40 parts by mass or less, and more preferably 30 parts by mass or less with respect to 100 parts by mass of the rubber component. A minimum is not specifically limited, What is necessary is just about 10 mass parts or more. Moreover, in the case of the sealant material used for a 2nd sealant layer, 40 mass parts or more are preferable with respect to 100 mass parts of rubber components, and 45 mass parts or more are more preferable. An upper limit is not specifically limited, What is necessary is just about 65 mass parts or less. If it is in the said range, an effect will be acquired more suitably.

The content of the plasticizer is preferably 1 part by mass or more, more preferably 5 parts by mass or more with respect to 100 parts by mass of the rubber component. If it is less than 1 part by mass, the adhesiveness to the tire is lowered, and there is a possibility that sufficient sealability cannot be obtained. The content is preferably 40 parts by mass or less, more preferably 20 parts by mass or less. If it exceeds 40 parts by mass, slipping may occur in the kneader and it may be difficult to knead the sealant material.

The sealant is preferably prepared by mixing pelletized butyl rubber, powder cross-linking agent, and powder cross-linking aid. Pelletized butyl rubber, liquid polybutene More preferably, it is prepared by mixing a plasticizer, powder carbon black, a powder crosslinking agent, and a powder crosslinking aid. Thereby, each raw material can be suitably supplied to a continuous kneader, and a sealant material can be produced with high productivity.

As the sealant material, a material in which a predetermined amount of a liquid polymer, an organic peroxide (crosslinking agent), and a crosslinking aid are blended with a rubber component containing butyl rubber is preferable.

Adhesiveness, sealability, fluidity by using two or more materials with different viscosities as butyl rubber and liquid polymer in particular, using a mixture of butyl rubber and liquid polymer such as liquid polybutene as the sealant material Processability is improved in a well-balanced manner. This is because a liquid polymer component is introduced into an organic peroxide cross-linking system using butyl rubber as a rubber component, and tackiness is imparted. By suppressing the flow, the adhesiveness, sealability, fluidity and processability are improved in a well-balanced manner.

The viscosity of the first sealant layer and the second sealant layer (the viscosity of the sealant material used for the first sealant layer and the second sealant layer) has a relationship that the viscosity of the first sealant layer is lower than the viscosity of the second sealant layer. If it is within the range to satisfy, it can be adjusted as appropriate.

The 0 ° C. viscosity of the first sealant layer is preferably less than 35 kPa · s, more preferably 25 kPa · s or less, and preferably 5 kPa · s or more, more preferably 10 kPa · s or more. The 95 ° C. viscosity of the first sealant layer is preferably less than 6 kPa · s, more preferably 4 kPa · s or less, and preferably 1 kPa · s or more, more preferably 2 kPa · s or more. If it is in the said range, an effect will be acquired more suitably.

The 0 ° C. viscosity of the second sealant layer is preferably 35 kPa · s or more, more preferably 40 kPa · s or more, and preferably 60 kPa · s or less, more preferably 45 kPa · s or less. The 95 ° C. viscosity of the second sealant layer is preferably 6 kPa · s or more, preferably 15 kPa · s or less, more preferably 9 kPa · s or less. If it is in the said range, an effect will be acquired more suitably.

The difference between the 0 ° C. viscosity of the first sealant layer and the 0 ° C. viscosity of the second sealant layer (the value obtained by subtracting the 0 ° C. viscosity of the first sealant layer from the 0 ° C. viscosity of the second sealant layer) is preferably 1 kPa · s. As mentioned above, More preferably, it is 10 kPa * s or more, Preferably it is 55 kPa * s or less, More preferably, it is 35 kPa * s or less.
The difference between the 95 ° C. viscosity of the first sealant layer and the 95 ° C. viscosity of the second sealant layer (the value obtained by subtracting the 95 ° C. viscosity of the first sealant layer from the 95 ° C. viscosity of the second sealant layer) is preferably 0.1 kPa. S or more, more preferably 2 kPa · s or more, preferably 25 kPa · s or less, more preferably 15 kPa · s or less, and further preferably 12 kPa · s or less.
If it is in the said range, an effect will be acquired more suitably.

In this specification, the viscosity of the sealant layer means the viscosity of the sealant material constituting the sealant layer, measured under the following conditions, the measured strain at each measurement temperature on the horizontal axis, and the shear viscosity on the vertical axis. The maximum value of the shear viscosity when creating the graph is the viscosity at each temperature (0 ° C., 95 ° C.).
FIG. 10 shows an outline of an example in the case where the steady flow shear viscosity of the sealant material is measured and a graph in which the measured strain is taken on the horizontal axis and the shear viscosity is taken on the vertical axis is created.
<Measurement conditions>
Measuring machine: Rheometer MCR52 (manufactured by Anton Paar)
Measurement mode: Steady flow shear viscosity Measurement temperature: 0 ° C or 95 ° C
Preheating time: 1 minute (time from being sandwiched between plates heated to the set temperature)
Gap: 1mm (Distance between plates, but no sealant sticking out)
Measurement time: 15 (seconds)
Measurement strain: 0 to 10,000 (%)
Shear rate: 6 (1 / s)
Rotor shape: Circular plate

The above-mentioned materials are mixed to prepare a sealant material, and the produced sealant material is applied to the inner circumferential surface of the tire (preferably the inner radial portion of the inner liner), so that the inner liner is radially inward of the tire. A sealant tire having a sealant layer can be manufactured, and mixing of each material constituting the sealant material can be performed using, for example, a known continuous kneader. Especially, it is preferable to mix using the multi-axis kneading extruder of the same direction rotation or a different direction rotation, especially a biaxial kneading extruder.

The continuous kneader (particularly a twin-screw kneading extruder) preferably has a plurality of supply ports for supplying raw materials, more preferably has at least three supply ports, and at least 3 upstream, intermediate and downstream sides. More preferably, it has one supply port. By sequentially supplying the various raw materials to a continuous kneader (particularly, a twin-screw kneading extruder), the various raw materials are mixed, and a sealant material is successively prepared.

It is preferable to supply the raw materials to a continuous kneader (particularly, a twin-screw kneading extruder) in order from a material having a higher viscosity. Thereby, each material is fully mixed and the sealant material with fixed quality can be prepared. In addition, when the powder material is added, the kneadability is improved.

The organic peroxide is preferably supplied to the continuous kneader (particularly, the twin-screw kneading extruder) from the supply port on the downstream side. Thereby, since the time from supplying the organic peroxide to applying the sealant material to the tire can be shortened, it can be applied to the tire before the sealant material is cured, and the sealant tire can be manufactured more stably.

If a large amount of liquid polymer is put into a continuous kneader (especially a twin screw kneading extruder) at a time, kneading will not be successful. It is preferable to carry out from the mouth. Thereby, kneading | mixing of a sealant material can be performed more suitably.

When a continuous kneader (especially a biaxial kneader extruder) is used, the sealant material is a continuous kneader (especially a biaxial kneader extruder) having at least three supply ports, and the continuous kneader (especially a two-screw kneader extruder). A rubber component such as butyl rubber, an inorganic filler, and a crosslinking aid are supplied from a supply port on the upstream side of the shaft kneading extruder, and a liquid polymer B is supplied from a supply port on the middle stream side, The liquid polymer A, the organic peroxide, and the plasticizer are preferably supplied from the supply port, and are preferably prepared by kneading and extruding. In addition, although you may supply the whole quantity or one part of each material, such as a liquid polymer, from each supply port, it is preferable to supply 95 mass% or more in the whole quantity of each material.

It is preferable that all the raw materials charged into the continuous kneader are controlled by a supply device capable of quantitative supply control and are charged into the continuous kneader. This makes it possible to prepare the sealant material in a continuous and automated state.

The supply device is not particularly limited as long as the quantitative supply control is possible, and a known supply device can be used. For example, a screw feeder, a plunger pump, a gear pump, a Mono pump, or the like can be used.

Solid raw materials (particularly pellets and powders) such as pelletized butyl rubber, powder carbon black, powder cross-linking agent, and powder cross-linking aid are quantitatively supplied using a screw feeder. It is preferable. As a result, it becomes possible to supply a solid raw material accurately and quantitatively, and it is possible to manufacture a higher-quality sealant material, and thus a higher-quality sealant tire.

Moreover, it is preferable to supply each solid raw material with a separate supply device. Thereby, since it is not necessary to blend each raw material beforehand, supply of the material at the time of mass production becomes easy.

The plasticizer is preferably supplied in a fixed amount using a plunger pump. As a result, it becomes possible to supply the plasticizer accurately and quantitatively, and it is possible to manufacture a higher-quality sealant material, and thus a higher-quality sealant tire.

The liquid polymer is preferably supplied in a fixed amount using a gear pump. As a result, the liquid polymer can be accurately and quantitatively supplied, and a higher-quality sealant material, and thus a higher-quality sealant tire can be manufactured.

The supplied liquid polymer is preferably controlled at a constant temperature. By controlling at a constant temperature, it becomes possible to quantitatively supply the liquid polymer with higher accuracy. The temperature of the supplied liquid polymer is preferably 20 to 90 ° C, more preferably 40 to 70 ° C.

Mixing in a continuous kneader (particularly a twin-screw kneading extruder) is preferably carried out at a barrel temperature of 30 (preferably 50) to 150 ° C. from the viewpoints of ease of mixing, extrudability, dispersibility, and crosslinking reaction. .

From the viewpoint of sufficient mixing properties, the mixing time of the material supplied on the upstream side is preferably 1 to 3 minutes, and the mixing time of the material supplied on the midstream side is preferably 1 to 3 minutes. On the other hand, from the viewpoint of preventing crosslinking, the mixing time of the material supplied on the downstream side is preferably 0.5 to 2 minutes. In addition, each mixing time means the residence time until it is discharged | emitted after supplying to a continuous kneading machine (especially biaxial kneading extruder), for example, the mixing time of the material supplied downstream is downstream. It is the residence time from the time of supply to the supply port until it is discharged.

The temperature of the sealant material discharged from the discharge port can be adjusted by adjusting the screw speed of the continuous kneader (especially the twin-screw kneading extruder) and the temperature controller, which in turn can control the curing acceleration rate of the sealant material. . In a continuous kneader (particularly a twin-screw kneading extruder), kneadability and material temperature increase as the number of rotations of the screw is increased. Note that the number of rotations of the screw does not affect the discharge amount. The number of rotations of the screw is preferably 50 to 700 (preferably 550) rpm from the viewpoint of sufficient mixing properties and control of the curing acceleration rate.

The temperature of the sealant material discharged from the discharge port of the continuous kneader (particularly the twin-screw kneading extruder) is preferably 70 to 150 ° C. from the viewpoint of sufficient mixing properties and control of the curing acceleration rate, It is more preferable that it is 90-130 degreeC. When the temperature of the sealant material is within the above range, a crosslinking reaction starts from the time of application, and has good adhesiveness to the tire inner peripheral surface, and the crosslinking reaction proceeds more suitably, and a sealant tire with high sealing properties is obtained. Can be manufactured. Moreover, the bridge | crosslinking process mentioned later is not required.

The amount of the sealant material discharged from the discharge port of the continuous kneader (particularly, the twin-screw kneading extruder) is determined based on the amount of raw material supplied to the supply port. The supply amount of the raw material to the supply port is not particularly limited, and can be appropriately set by those skilled in the art.
It is preferable that the amount (discharge amount) of the sealant material discharged from the discharge port is substantially constant because a sealant tire excellent in uniformity and sealability can be suitably obtained.
Here, in this specification, the discharge amount being substantially constant means that the fluctuation of the discharge amount is 93 to 107% (preferably 97 to 103%, more preferably 98 to 102%, and still more preferably 99 to 101%. ).

It is preferable to connect a nozzle to the discharge port of a continuous kneader (particularly a biaxial kneading extruder). A continuous kneader (especially a twin-screw kneading extruder) can discharge a material at a high pressure, so that the prepared sealant material is attached to a discharge port by a nozzle (preferably a small-diameter nozzle having high resistance). Bead-like) and can be attached to the tire. That is, the thickness of the sealant material is substantially reduced by discharging the sealant material from a nozzle connected to the discharge port of a continuous kneader (especially a twin-screw kneading extruder) and sequentially applying it to the inner peripheral surface of the tire. It becomes constant, can prevent deterioration of tire uniformity, and can produce a sealant tire excellent in weight balance.

Next, the mixed sealant material is discharged directly from the nozzle connected to the discharge port of an extruder such as a continuous kneader (especially a twin-screw kneading extruder) to feed directly to the inner peripheral surface of the vulcanized tire. A sealant tire is manufactured by applying to the inner peripheral surface. As a result, the sealant material mixed in a twin-screw kneading extruder and the like, and the progress of the crosslinking reaction in the extruder can be directly applied to the tire inner peripheral surface. While having favorable adhesiveness to a surrounding surface, a crosslinking reaction advances suitably. Thereby, the sealant material applied to the inner peripheral surface of the tire preferably forms a sealant layer while maintaining a substantially string-like shape. Accordingly, sealant coating can be performed in a series of steps, and productivity is further improved. Also, by applying a sealant material to the inner peripheral surface of a vulcanized tire, a sealant tire can be manufactured with higher productivity. Furthermore, it is preferable that the sealant material discharged from the nozzle connected to the discharge port of the continuous kneader (particularly, the twin-screw kneading extruder) is sequentially applied directly to the inner peripheral surface of the tire. As a result, since the sealant material in which the progress of the crosslinking reaction in the continuous kneader (particularly the twin-screw kneading extruder) is suppressed can be continuously applied to the tire inner peripheral surface as it is, the crosslinking reaction starts from the time of application. In addition to having good adhesion to the tire inner peripheral surface, a cross-linking reaction suitably proceeds, and a sealant tire with better productivity and excellent weight balance can be produced.

The sealant material may be applied to the inner peripheral surface of the tire at least on the inner peripheral surface of the tire corresponding to the tread portion, more preferably on at least the inner peripheral surface of the tire corresponding to the breaker. By omitting application to a portion where application of the sealant material is unnecessary, a sealant tire can be manufactured with higher productivity.
Here, the inner peripheral surface of the tire corresponding to the tread portion means the inner peripheral surface of the tire located inside the tire radial direction of the tread portion in contact with the road surface, and the inner peripheral surface of the tire corresponding to the breaker is It means the inner peripheral surface of the tire located on the inner side in the tire radial direction of the breaker. The breaker is a member arranged inside the tread and outside the carcass in the radial direction. Specifically, the breaker is a member shown in the breaker 16 of FIG.

Usually, an unvulcanized tire is vulcanized using a bladder. This bladder expands during vulcanization and comes into close contact with the inner peripheral surface (inner liner) of the tire. Thus, a release agent is usually applied to the inner peripheral surface (inner liner) of the tire so that the bladder and the inner peripheral surface (inner liner) of the tire do not adhere when vulcanization is completed.

As the release agent, a water-soluble paint or a release rubber is usually used. However, if a release agent is present on the inner peripheral surface of the tire, the adhesiveness between the sealant material and the inner peripheral surface of the tire may be reduced. Therefore, it is preferable to remove the release agent in advance from the inner peripheral surface of the tire. In particular, it is more preferable to remove the release agent in advance at least in the portion of the inner peripheral surface of the tire where the application of the sealant material is started. It is more preferable to remove the release agent in advance from all portions of the inner peripheral surface of the tire where the sealant material is applied. Thereby, the adherence of the sealant material to the inner peripheral surface of the tire is further improved, and a sealant tire with higher sealing performance can be manufactured.

The method for removing the release agent from the inner peripheral surface of the tire is not particularly limited, and examples thereof include known methods such as buff treatment, laser treatment, high-pressure water washing, and removal with a detergent (preferably a neutral detergent).

Here, an example of the manufacturing equipment used for the manufacturing method of a sealant tire is demonstrated easily using FIG.
The manufacturing equipment includes a twin-screw kneading extruder 60, a material feeder 62 for supplying raw materials to the twin-screw kneading extruder 60, a rotation driving device 50 for fixing and rotating the tire 10 and moving the tire 10 in the width direction and the radial direction of the tire. Have The biaxial kneading extruder 60 has five supply ports 61. Specifically, it has three upstream supply ports 61a, one midstream supply port 61b, and one downstream supply port 61c. Furthermore, the nozzle 30 is connected to the discharge port of the twin-screw kneading extruder 60.

The raw materials are sequentially supplied from the material feeder 62 to the twin-screw kneading extruder 60 through the supply port 61 of the twin-screw kneading extruder 60, and each raw material is kneaded by the twin-screw kneading extruder 60, so that the sealant material is sequentially prepared. Is done. The prepared sealant material is continuously discharged from the nozzle 30 connected to the discharge port of the twin-screw kneading extruder 60. The tire is rotated and / or raised and lowered (moved in the width direction and / or the radial direction of the tire) while rotating the tire with the rotation drive device 50, and the sealant material discharged from the nozzle 30 is sequentially applied directly to the inner peripheral surface of the tire. Thus, the sealant material can be continuously spirally attached to the inner peripheral surface of the tire. That is, the sealant material continuously discharged from the continuous kneader (especially the biaxial kneader-extruder) is sequentially applied to the inner peripheral surface of the tire while moving the tire in the width direction and / or the radial direction while rotating the tire. By applying directly, the sealant material can be continuously spirally attached to the inner peripheral surface of the tire.

By continuously sticking a sealant material on the inner peripheral surface of the tire in a spiral shape, deterioration of tire uniformity can be prevented and a sealant tire excellent in weight balance can be manufactured. Also, the sealant material can be formed in a uniform sealant layer in the tire circumferential direction and the tire width direction (especially in the tire circumferential direction) by continuously affixing the sealant material on the inner peripheral surface of the tire in a spiral shape. Highly stable sealant tires can be manufactured stably with good productivity. The sealant material is preferably pasted so as not to overlap in the width direction, and more preferably pasted without any gap. As a result, deterioration of tire uniformity can be further prevented, and a more uniform sealant layer can be formed.

In addition, raw materials are sequentially supplied to a continuous kneader (especially a twin-screw kneading extruder), and a sealant material is sequentially prepared by a continuous kneader (especially a twin-screw kneading extruder), and the prepared sealant material is continuously kneaded. It is continuously discharged from a nozzle connected to a discharge port of a machine (particularly a biaxial kneading extruder), and sealant materials are sequentially applied directly to the inner peripheral surface of the tire. Thereby, a sealant tire can be manufactured with high productivity.

The sealant layer is preferably formed by applying a substantially string-like sealant material to the inner peripheral surface of the tire in a spiral manner. Thereby, it becomes possible to form the sealant layer comprised by the substantially string-like sealant material continuously arranged spirally along the inner peripheral surface of the tire on the inner peripheral surface of the tire.
In addition, when laminating the first sealant layer and the second sealant layer, first arrange the first sealant layer in a spiral shape, and then arrange the second sealant layer in a spiral shape so as to overlap the first sealant layer. do it.

When the sealant material has a substantially string-like shape, a sealant layer composed of one sealant material can be formed by continuously applying the sealant material in a spiral manner to the inner peripheral surface of the tire. If the sealant material has a substantially string-like shape, the applied sealant material has a certain thickness, so even a sealant layer consisting of one sealant material can prevent deterioration of tire uniformity and weight. A sealant tire having excellent balance and excellent sealing properties can be manufactured.

The number of times the sealant material is wound around the inner peripheral surface of the tire is preferable because it can prevent deterioration of the tire uniformity, has an excellent weight balance, and can produce a sealant tire having good sealability with higher productivity. It is 20-70 times, More preferably, it is 20-60 times, More preferably, it is 35-50 times. Here, the number of times of winding is 2 means that the sealant material is applied so as to make two rounds on the inner circumferential surface of the tire. In FIG. 4, the number of times of winding the sealant material is 6.

By using a continuous kneader (especially a twin-screw kneading extruder), the preparation (kneading) of the sealant material and the discharge (coating) of the sealant material can be performed simultaneously, with high viscosity and high adhesiveness. The sealant material, which is difficult to handle, can be applied directly to the inner peripheral surface of the tire without handling, and a sealant tire can be manufactured with high productivity. In addition, when a sealant material is prepared by kneading with a batch type kneader, including the curing agent, the time from preparation of the sealant material to application to the tire is not constant, but raw materials containing organic peroxide are continuously kneaded. The time from the preparation of the sealant material to the application to the tire is constant by sequentially applying the sealant material sequentially prepared by mixing with a machine (especially a twin-screw kneading extruder) to the inner peripheral surface of the tire. Therefore, when the sealant material is applied using a nozzle, the discharge amount of the sealant material from the nozzle is stabilized, and further, the adhesive becomes constant adhesiveness while suppressing the decrease in the adhesiveness of the sealant material to the tire. Highly viscous, sticky, and difficult to handle sealant materials can be applied to the tire's inner surface with high accuracy, producing stable and consistent sealant tires. That.

Next, a method for applying a sealant material to the inner peripheral surface of the tire will be described below.

<First Embodiment>
In the first embodiment, the sealant tire rotates the tire and moves an adhesive sealant material to the inner peripheral surface of the tire by the nozzle while moving at least one of the tire and the nozzle in the width direction of the tire. When applying, the step (1) of measuring the distance between the inner peripheral surface of the tire and the tip of the nozzle by a non-contact displacement sensor, and at least one of the tire and the nozzle is arranged in the radial direction of the tire based on the measurement result. The step (2) of adjusting the distance between the inner peripheral surface of the tire and the tip of the nozzle to a predetermined distance by applying the sealant to the tire, and applying the sealant material to the inner peripheral surface of the tire with the adjusted distance. It can manufacture by performing the process (3) to perform.

The distance between the inner peripheral surface of the tire and the tip of the nozzle is measured using a non-contact displacement sensor, and the measurement result is fed back, so that the distance between the inner peripheral surface of the tire and the tip of the nozzle is kept constant. Can keep. And since the sealant material is applied to the inner peripheral surface of the tire while keeping the above distance constant, the thickness of the sealant material is uniform without being affected by unevenness of the tire shape or unevenness of the joints, etc. Can be. Furthermore, since it is not necessary to input coordinate values for each tire size as in the prior art, the sealant material can be applied efficiently.

Drawing 1 is an explanatory view showing typically an example of the application device used with the manufacturing method of a sealant tire. FIG. 2 is an enlarged view of the vicinity of the tip of the nozzle constituting the coating apparatus shown in FIG.

FIG. 1 shows a cross section obtained by cutting a part of the tire 10 in the meridian direction (cross section cut by a plane including the width direction and the radial direction of the tire), and FIG. 2 shows a part of the tire 10 around the tire. A cross section cut by a plane including a direction and a radial direction is shown. 1 and 2, the X direction is the tire width direction (axial direction), the Y direction is the tire circumferential direction, and the Z direction is the tire radial direction.

The tire 10 is set on a rotation drive device (not shown) that rotates the tire 10 while fixing and rotating the tire 10 in the width direction and the radial direction of the tire. This rotational drive device enables rotation around the tire axis, movement in the width direction of the tire, and movement in the radial direction of the tire independently.

The rotational drive device also includes a control mechanism (not shown) that can control the amount of movement of the tire in the radial direction. The control mechanism may be capable of controlling the amount of movement in the width direction of the tire and / or the rotational speed of the tire.

The nozzle 30 is attached to the tip of an extruder (not shown) and can be inserted inside the tire 10. Then, the adhesive sealant material 20 extruded from the extruder is discharged from the tip 31 of the nozzle 30.

The non-contact displacement sensor 40 is attached to the nozzle 30 and measures the distance d between the inner peripheral surface 11 of the tire 10 and the tip 31 of the nozzle 30.
Thus, the distance d measured by the non-contact displacement sensor is a distance in the radial direction of the tire between the inner peripheral surface of the tire and the tip of the nozzle.

In the sealant tire manufacturing method of the present embodiment, first, the tire 10 molded in the vulcanization process is set in a rotation drive device, and the nozzle 30 is inserted inside the tire 10. Then, as shown in FIGS. 1 and 2, the sealant material 20 is discharged from the nozzle 30 while rotating the tire 10 and moving the tire 10 in the width direction, so that it continues to the inner peripheral surface 11 of the tire 10. Apply it. The movement in the width direction of the tire 10 is performed along the profile shape of the inner peripheral surface 11 of the tire 10 that has been input in advance.

As will be described later, the sealant material 20 preferably has a substantially string-like shape. More specifically, the sealant material retains a substantially string-like shape when the sealant material is applied to the inner peripheral surface of the tire. In this case, the substantially string-like sealant material 20 is continuously attached to the inner peripheral surface 11 of the tire 10 in a spiral shape.

In the present specification, the substantially string-like shape means a shape having a length longer than a width and a certain width and thickness. FIG. 4 schematically shows an example of a state in which the substantially string-like sealant material is continuously attached in a spiral manner to the inner peripheral surface of the tire. FIG. 8 schematically shows an example of a cross section of the sealant material when the sealant material of FIG. 4 is cut along a straight line AA orthogonal to the application direction (length direction) of the sealant material. Thus, the substantially string-like sealant material has a certain width (a length indicated by W in FIG. 8) and a certain thickness (a length indicated by D in FIG. 8). Here, the width of the sealant material means the width of the sealant material after application, and the thickness of the sealant material means the thickness of the sealant material after application, more specifically, the thickness of the sealant layer. Means.

Specifically, the sealant material having a substantially string shape has a thickness of the sealant material (the thickness of the sealant material after application, the thickness of the sealant layer, the length indicated by D in FIG. 8), which will be described later. A sealant material satisfying a preferable numerical range of a preferable numerical range and a width of the sealant material (the width of the sealant material after application, the length indicated by W in FIG. 4, the length indicated by W ₀ in FIG. 6), More preferably, the sealant material satisfies a preferable numerical range of the ratio of the thickness of the sealant material and the width of the sealant material (the thickness of the sealant material / the width of the sealant material) described later. It is also a sealant material that satisfies a preferable numerical range of the cross-sectional area of the sealant material, which will be described later.

In the sealant tire manufacturing method of the present embodiment, the sealant material is applied to the inner peripheral surface of the tire by the following steps (1) to (3).

<Step (1)>
As shown in FIG. 2, a non-contact displacement sensor 40 measures a distance d between the inner peripheral surface 11 of the tire 10 and the tip 31 of the nozzle 30 before the sealant material 20 is applied. The measurement of the distance d is performed every time the sealant material 20 is applied to the inner peripheral surface 11 of each tire 10, and is performed from the start of application of the sealant material 20 to the end of application.

<Step (2)>
The measurement data of the distance d is transferred to the control mechanism of the rotary drive device. Based on the measurement data, the control mechanism adjusts the amount of movement in the radial direction of the tire so that the distance between the inner peripheral surface 11 of the tire 10 and the tip 31 of the nozzle 30 is a predetermined distance.

<Step (3)>
Since the sealant material 20 is continuously discharged from the tip 31 of the nozzle 30, the sealant material 20 is applied to the inner peripheral surface 11 of the tire 10 in which the interval is adjusted. Through the above steps (1) to (3), the sealant material 20 having a uniform thickness can be applied to the inner peripheral surface 11 of the tire 10.

FIG. 3 is an explanatory diagram schematically showing the positional relationship of the nozzle with respect to the tire.
As shown in FIG. 3, while the nozzle 30 moves to the position indicated by (a) to (d) with respect to the tire 10, the distance between the inner peripheral surface 11 of the tire 10 and the tip 31 of the nozzle 30 is set to a predetermined distance. it can be coated with a sealant material while maintaining the d _0.

The distance d ₀ after adjustment is preferably 0.3 mm or more, more preferably 1.0 mm or more, because the effect can be obtained more suitably. If it is less than 0.3 mm, the tip of the nozzle is too close to the inner peripheral surface of the tire, so that it becomes difficult to apply a sealant material having a predetermined thickness. Further, the adjusted distance d ₀ is preferably 3.0 mm or less, more preferably 2.0 mm or less. If it exceeds 3.0 mm, the sealant material cannot be successfully adhered to the tire, and the production efficiency may be reduced.
Here, the adjusted distance d ₀ is the distance in the tire radial direction between the inner peripheral surface of the tire and the tip of the nozzle after the adjustment in the step (2).

Further, for the reason that the effect can be more suitably obtained, the adjusted interval d ₀ is preferably 30% or less, more preferably 20% or less of the thickness of the sealant material after application, and the sealant material after application. The thickness is preferably 5% or more, more preferably 10% or more.

The thickness of the sealant material (the thickness of the sealant material after application, the thickness of the sealant layer, the length indicated by D in FIG. 8) is not particularly limited, but is preferable because the effect is more suitably obtained. Is 1.0 mm or more, more preferably 1.5 mm or more, still more preferably 2.0 mm or more, particularly preferably 2.5 mm or more, preferably 10.0 mm or less, more preferably 8.0 mm or less, Preferably it is 5.0 mm or less. When it is less than 1.0 mm, it is difficult to reliably close the puncture hole when the tire is punctured. Moreover, even if it exceeds 10.0 mm, the effect of closing the puncture hole does not change so much and the weight of the tire increases, which is not preferable. The thickness of the sealant material can be adjusted by adjusting the rotational speed of the tire, the moving speed in the width direction of the tire, the distance between the tip of the nozzle and the inner peripheral surface of the tire, and the like.

It is preferable that the thickness of the sealant material (the thickness of the sealant material after application, the thickness of the sealant layer) is substantially constant. Thereby, the deterioration of the uniformity of a tire can be prevented more, and the sealant tire more excellent in weight balance can be manufactured.
Here, in this specification, the thickness is substantially constant means that the variation in thickness is 90 to 110% (preferably 95 to 105%, more preferably 98 to 102%, still more preferably 99 to 101%. ).

It is preferable to use a substantially string-like sealant material because the nozzle is also less clogged and excellent in operational stability, and the effect is more suitably obtained. It is more preferable to affix in a spiral manner on the inner peripheral surface of the tire. However, a sealant material that is not substantially string-shaped may be used, and the sealant material may be applied by spraying on the inner peripheral surface of the tire.

When the sealant material having a substantially string shape is used, the width of the sealant material (the width of the sealant material after application, the length indicated by W in FIG. 4) is not particularly limited, but the effect is more preferably obtained. For the reason, it is preferably 0.8 mm or more, more preferably 1.3 mm or more, and further preferably 1.5 mm or more. If it is less than 0.8 mm, the number of times the sealant material is wound around the inner peripheral surface of the tire increases, and the production efficiency may be reduced. The width of the sealant material is preferably 18 mm or less, more preferably 13 mm or less, still more preferably 9.0 mm or less, particularly preferably 7.0 mm or less, most preferably 6.0 mm or less, and most preferably 5.0 mm. It is as follows. When it exceeds 18 mm, there is a possibility that weight imbalance tends to occur.

The thickness of the sealant (the thickness of the sealant after application, the thickness of the sealant layer, the length indicated by D in FIG. 8) and the width of the sealant (the width of the sealant after application, in FIG. 4) , W) (the thickness of the sealant material / the width of the sealant material) is preferably 0.6 to 1.4, more preferably 0.7 to 1.3, and still more preferably 0.8. It is 8 to 1.2, particularly preferably 0.9 to 1.1. As the ratio is closer to 1.0, the shape of the sealant material becomes an ideal string shape, and a sealant tire having a high sealing property can be manufactured with higher productivity.

The second sealant layer (the sealant material used for the second sealant layer) is preferably thicker than the first sealant layer (the sealant material used for the first sealant layer). Thereby, the sealing performance after driving | running | working can be improved more.

The thickness of the first sealant layer (the sealant material used for the first sealant layer) is preferably 1 mm or more, more preferably 1.3 mm or more, still more preferably 2 mm or more, and preferably 5 mm or less, more preferably Is 4 mm or less, more preferably 3 mm or less.
The thickness of the second sealant layer (sealant material used for the second sealant layer) is preferably 1 mm or more, more preferably 1.3 mm or more, still more preferably 2 mm or more, and preferably 5 mm or less, more preferably Is 4 mm or less, more preferably 3 mm or less.
The total thickness of the first sealant layer and the second sealant layer is preferably 7 mm or less, more preferably 6 mm or less, and preferably 3 mm or more, more preferably 4 mm or more.
If it is in the said range, an effect will be acquired more suitably.

The cross-sectional area of the sealant material (the cross-sectional area of the sealant material after application, in FIG. 8, the area calculated by D × W) is preferably 0.8 mm ² or more, because the effect is more suitably obtained. preferably 1.95 mm ² or more, more preferably 3.0 mm ² or more, particularly preferably 3.75 mm ² or more, preferably 180 mm ² or less, more preferably 104 mm ² or less, more preferably 45 mm ² or less, particularly preferably Is 35 mm ² or less, most preferably 25 mm ² or less.

The width of the region where the sealant material is affixed (hereinafter also referred to as the width of the affixed region and the width of the sealant layer, the length represented by 6 × W in FIG. 4, and W ₁ + 6 × W ₀ in FIG. 6. The length represented is not particularly limited, but 80% or more of the tread ground contact width is preferable, 90% or more is more preferable, 100% or more is more preferable, and 120% is more preferable because the effect is more suitably obtained. % Or less is preferable, and 110% or less is more preferable.

The width of the sealant layer is preferably 85 to 115%, more preferably 95 to 105% of the tire breaker width (the length of the breaker in the tire width direction) because the effect can be obtained more suitably. More preferred.
In the present specification, when a plurality of breakers are provided in the tire, the length in the tire width direction of the breaker is the tire width direction of the breaker having the longest length in the tire width direction among the plurality of breakers. It means length.

In the present specification, the tread ground contact width is determined as follows. First, the ground contact position on the outermost side in the tire axial direction when a normal load is loaded on a normal rim that is assembled with a regular rim and filled with a regular internal pressure, and a normal load is applied to a flat surface with a camber angle of 0 degrees. Is defined as “grounding end” Te. A distance in the tire axial direction between the ground contact ends Te and Te is defined as a tread ground contact width TW. When there is no notice in particular, the dimension of each part of a tire, etc. are values measured in this normal state.

The “regular rim” is a rim defined for each tire in the standard system including the standard on which the tire is based. “Standard rim” for JATMA and “Design Rim” for TRA. If it is ETRTO, it becomes “Measuring Rim”. The “regular internal pressure” is the air pressure defined by each standard for each tire in the standard system including the standard on which the tire is based, and is “maximum air pressure” for JATMA, and “ The maximum value described in TIRE LOAD LIMITS AT VARIOUS COLD INFRATION PRESURES is “INFLATION PRESSURE” if it is ETRTO, but 180 kPa if the tire is for passenger cars.

In addition, the “regular load” is a load determined by each standard for each tire in a standard system including the standard on which the tire is based. “JATMA” indicates “maximum load capacity”, and TRA indicates The maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFRATION PRESURES” is “LOAD CAPACITY” if it is ETRTO, but if the tire is for a passenger car, the load is equivalent to 88% of the above load.

The rotation speed of the tire when applying the sealant material is not particularly limited, but is preferably 5 m / min or more, more preferably 10 m / min or more, and preferably 30 m from the reason that the effect is more suitably obtained. / Min or less, more preferably 20 m / min or less. When it is less than 5 m / min and when it exceeds 30 m / min, it becomes difficult to apply a sealant material having a uniform thickness.

By using a non-contact type displacement sensor, the risk of failure due to the sealant material adhering to the sensor can be reduced. The non-contact type displacement sensor to be used is not particularly limited as long as it can measure the distance between the inner peripheral surface of the tire and the tip of the nozzle, and examples thereof include a laser sensor, an optical sensor, and a capacitance sensor. . These sensors may be used independently and may use 2 or more types together. Among these, from the viewpoint of measuring rubber, a laser sensor and an optical sensor are preferable, and a laser sensor is more preferable. When using a laser sensor, irradiate the inner peripheral surface of the tire with laser, measure the distance between the inner peripheral surface of the tire and the tip of the laser sensor from the reflection of the laser, and use the value to determine the tip of the laser sensor and the tip of the nozzle. The distance between the inner peripheral surface of the tire and the tip of the nozzle can be obtained.

The position of the non-contact type displacement sensor is not particularly limited as long as the distance between the inner peripheral surface of the tire before applying the sealant material and the tip of the nozzle can be measured, but it is preferably attached to the nozzle. It is more preferable to install it at a position where it does not adhere.

In addition, the number and size of the non-contact type displacement sensor are not particularly limited.

Non-contact type displacement sensors are sensitive to heat, and therefore, protection using heat insulating material and / or cooling using air or the like is performed in order to prevent thermal effects from the high-temperature sealant material discharged from the nozzle. Is preferred. Thereby, the durability of the sensor can be improved.

In the description of the first embodiment, an example in which the nozzle does not move and the tire moves as the movement in the width direction and the radial direction of the tire has been described, but the nozzle may move without the tire moving, Both nozzles may move.

Moreover, it is preferable that a rotation drive device has a means to expand the width | variety of the bead part of a tire. When applying the sealant material to the tire, the sealant material can be easily applied to the tire by widening the width of the bead portion of the tire. In particular, when the nozzle is introduced in the vicinity of the inner peripheral surface of the tire after the tire is set on the rotational drive device, the nozzle can be introduced simply by moving the nozzle in parallel, which facilitates control and improves productivity.

The means for expanding the width of the bead portion of the tire is not particularly limited as long as the width of the bead portion of the tire can be increased, but two sets of apparatuses having a plurality of (preferably two) rolls whose positions do not change from each other. And a mechanism that moves each in the tire width direction. The device may be inserted into the tire from both sides of the tire opening to increase the width of the tire bead.

In the above production method, the sealant material, which is mixed in a twin-screw kneading extruder and the like and the progress of the crosslinking reaction in the extruder is suppressed, is applied to the tire inner peripheral surface as it is, so that the crosslinking reaction starts from the time of application, While having good adhesiveness to the tire inner peripheral surface, the crosslinking reaction proceeds more suitably, and a sealant tire having high sealing properties can be produced. Therefore, it is not necessary to further crosslink the sealant tire coated with the sealant material, and good productivity can be obtained.

In addition, you may perform the bridge | crosslinking process which further bridge | crosslinks the sealant tire which apply | coated the sealant material as needed.
In the crosslinking step, it is preferable to heat the sealant tire. As a result, the crosslinking rate of the sealant material can be improved, the crosslinking reaction can proceed more suitably, and a sealant tire can be manufactured with higher productivity. The heating method is not particularly limited, and a known method can be adopted, but a method using an oven is preferable. In the crosslinking step, for example, the sealant tire may be placed in an oven at 70 ° C. to 190 ° C. (preferably 150 ° C. to 190 ° C.) for 2 to 15 minutes.
In addition, it is preferable to rotate the tire in the tire circumferential direction at the time of cross-linking because the cross-linking reaction can be performed without preventing the flow even with a sealant material that is easy to flow immediately after application and without deteriorating uniformity. The rotation speed is preferably 300 to 1000 rpm. Specifically, for example, an oven with a rotation mechanism may be used as the oven.

Even if the crosslinking step is not performed separately, it is preferable to rotate the tire in the tire circumferential direction until the crosslinking reaction of the sealant material is completed. As a result, even a sealant material that is easy to flow immediately after coating can be prevented from flowing and a crosslinking reaction can be performed without deteriorating uniformity. The rotation speed is the same as in the crosslinking step.

In order to improve the crosslinking rate of the sealant material, it is preferable to warm the tire in advance before applying the sealant material. Thereby, a sealant tire can be manufactured with higher productivity. The preheating temperature of the tire is preferably 40 to 100 ° C, more preferably 50 to 70 ° C. By setting the preheating temperature of the tire within the above range, the crosslinking reaction is suitably started from the time of application, the crosslinking reaction proceeds more suitably, and a sealant tire having a high sealing property can be manufactured. Further, by setting the preheating temperature of the tire within the above range, it is not necessary to perform a crosslinking step, so that a sealant tire can be manufactured with high productivity.

A continuous kneader (particularly a twin-screw kneading extruder) generally operates continuously. On the other hand, when manufacturing a sealant tire, it is necessary to replace the tire when application to one tire is completed. At this time, the following methods (1) and (2) may be employed in order to manufacture a higher-quality sealant tire while suppressing a decrease in productivity. The method (1) has a demerit of a decrease in quality, and the method (2) has an increase in cost. Therefore, it may be properly used depending on the situation.
(1) The continuous kneader and all the supply devices are simultaneously operated and stopped to control the supply of the sealant material to the inner peripheral surface of the tire. That is, when the application to one tire is completed, the continuous kneader, All the supply devices are stopped at the same time, the tire is replaced (preferably within 1 minute), the continuous kneader and all the supply devices are operated simultaneously, and the application to the tire is resumed. By performing tire replacement promptly (preferably within 1 minute), deterioration in quality can be suppressed.
(2) The supply of the sealant material to the inner peripheral surface of the tire is controlled by switching the flow path while the continuous kneader and all the supply devices are operating. That is, the inner peripheral surface of the tire is controlled by the continuous kneader. A flow path different from the nozzle that feeds directly to the nozzle is provided, and when the application to one tire is completed, the prepared sealant material may be discharged from the other flow path until the replacement of the tire is completed. In this method, since the sealant tire can be manufactured with the continuous kneader and all the supply devices being operated, a higher quality sealant tire can be manufactured.

In addition, it does not specifically limit as a carcass cord used for the carcass of the said sealant tire, A fiber cord, a steel cord, etc. are mentioned. Among these, a steel cord is preferable. In particular, a steel cord made of a hard steel wire specified in JIS G3506 is desirable. In sealant tires, the use of high-strength steel cords as carcass cords, rather than the commonly used fiber cords, greatly reduces the resistance to side-cuts (with respect to cuts on the side of the tire that occurs when riding on curbs, etc.) Resistance) and the puncture resistance of the entire tire including the side portions can be further improved.

The structure of the steel cord is not particularly limited. For example, a single-twisted steel cord having a 1 × n configuration, a layer-twisted steel cord having a k + m configuration, a bundle-twisting steel cord having a 1 × n configuration, and a double-twisted steel having an m × n configuration. Examples include codes. Here, the single stranded steel cord having a 1 × n configuration is a one-layer stranded steel cord obtained by twisting n filaments. The k + m layer-twisted steel cord is a steel cord having a two-layer structure with different twist directions and twist pitches, and having k filaments in the inner layer and m filaments in the outer layer. Further, the bundle-twisted steel cord having a 1 × n configuration is a bundle-twisted steel cord obtained by bundling n filaments and twisting them together. Further, the double twisted steel cord having an m × n configuration is a double twisted steel cord obtained by twisting m strands obtained by twisting n filaments. n is an integer of 1 to 27, k is an integer of 1 to 10, and m is an integer of 1 to 3.

The twist pitch of the steel cord is preferably 13 mm or less, more preferably 11 mm or less, and preferably 5 mm or more, more preferably 7 mm or more.

The steel cord preferably includes at least one typed filament spirally typed. Such a shaped filament can provide a relatively large gap in the steel cord to improve rubber permeability, maintain elongation at low load, and prevent occurrence of molding defects during vulcanization molding.

The surface of the steel cord is preferably plated with brass (brass), Zn or the like in order to improve the initial adhesion to the rubber composition.

The steel cord preferably has an elongation at a load of 50 N of 0.5 to 1.5%. Note that if the elongation at the time of 50 N load exceeds 1.5%, the elongation of the reinforcing cord becomes small at the time of high load, and there is a possibility that the disturbance absorbing ability cannot be maintained. On the other hand, if the elongation at the time of 50 N load is less than 0.5%, it cannot be sufficiently stretched during vulcanization molding, which may cause molding failure. From such a viewpoint, the elongation at the time of the 50N load is more preferably 0.7% or more, and more preferably 1.3% or less.

The end of the steel cord is preferably 20 to 50 (lines / 5 cm).

Second Embodiment
If only the method of the first embodiment is used, when the sealant material has a substantially string shape, it may be difficult to apply the sealant material to the inner peripheral surface of the tire. As a result of studies by the present inventors, it has become clear that there is a problem that it is easy. In the second embodiment, in the manufacturing method of the sealant tire, after attaching the sealant material and the distance between the inner circumferential surface and the tip of the nozzle of the tire at a distance d _1, the distance the distance d ₁ is larger than the distance d ₂ and a sealant material is pasted. Thereby, the width | variety of the sealant material corresponding to a sticking start part can be enlarged by making the space | interval of the inner peripheral surface of a tire and the front-end | tip of a nozzle close at the time of a sticking start, The tire corresponding to a tread part at least The sealant material having adhesiveness and a substantially string-like shape is continuously attached in a spiral shape to the inner peripheral surface of the sealant, and at least one of the end portions in the length direction of the sealant material is in the length direction. It is possible to easily manufacture a sealant tire characterized by being a wide portion that is wider than a portion adjacent to. In the sealant tire, by increasing the width of the sealant material corresponding to the pasting start portion, it is possible to improve the adhesive force of the portion and prevent the sealant material from peeling off at the portion.
In the description of the second embodiment, only the points different from the first embodiment will be mainly described, and the description overlapping with the first embodiment will be omitted.

5 is an enlarged view of the vicinity of the tip of the nozzle constituting the coating apparatus shown in FIG. 1, where (a) shows a state immediately after the start of application of the sealant material, and (b) shows a state after a predetermined time has elapsed. Yes.

FIG. 5 shows a cross section of a part of the tire 10 cut by a plane including the circumferential direction and the radial direction of the tire. In FIG. 5, the X direction is the tire width direction (axial direction), the Y direction is the tire circumferential direction, and the Z direction is the tire radial direction.

In the second embodiment, first, the tire 10 molded in the vulcanization process is set in a rotation drive device, and the nozzle 30 is inserted inside the tire 10. As shown in FIGS. 1 and 5, the sealant material 20 is discharged from the nozzle 30 while rotating the tire 10 and moving the tire 10 in the width direction. Apply it. The movement of the tire 10 in the width direction is performed, for example, along the profile shape of the inner peripheral surface 11 of the tire 10 that has been input in advance.

Since the sealant material 20 has adhesiveness and has a substantially string-like shape, the sealant material 20 is continuously attached in a spiral shape to the inner peripheral surface 11 of the tire 10 corresponding to the tread portion.

At this time, for a predetermined time from the start of application, the sealant material 20 is applied with the distance d ₁ between the inner peripheral surface 11 of the tire 10 and the tip 31 of the nozzle 30 as shown in FIG. 5A. wear. Then, after a predetermined time has elapsed, as shown in FIG. 5 (b), by changing the interval distance d ₁ is greater than the distance d ₂ by moving the tire 10 radially paste sealant material 20.

Incidentally, before exiting the paste sealant material, it may be returned to a distance d ₁ to the distance from the distance d _2, but the production efficiency, in terms of weight balance of the tire, and terminates the paste sealant material it is preferable that the distance d ₂ to the.

Further, it is preferable to keep the value of the distance d ₁ constant for a predetermined time from the start of the pasting, and to keep the value of the distance d ₂ constant after the predetermined time has elapsed, but the relationship of d ₁ <d ₂ is satisfied. As long as it is satisfied, the values of the distances d ₁ and d ₂ are not necessarily constant.

Although the value of the distance d ₁ is not particularly limited, it is preferably 0.3 mm or more, more preferably 0.5 mm or more, because the effect is more suitably obtained. If it is less than 0.3 mm, the tip of the nozzle is too close to the inner peripheral surface of the tire, so that the sealant material tends to adhere to the nozzle and the frequency of cleaning the nozzle may increase. The distance d ₁ is preferably 2 mm or less, more preferably 1 mm or less. If it exceeds 2 mm, the effect of providing the wide portion may not be sufficiently obtained.

Although the value of the distance d ₂ is not particularly limited, it is preferably 0.3 mm or more, more preferably 1 mm or more, and preferably 3 mm or less, more preferably 2 mm or less, because the effect can be obtained more suitably. It is. The distance d ₂ is preferably the same as the distance d ₀ after the above adjustment.

In the present specification, the distances d ₁ and d ₂ between the inner peripheral surface of the tire and the tip of the nozzle are radial distances between the inner peripheral surface of the tire and the tip of the nozzle.

The rotation speed of the tire when the sealant material is applied is not particularly limited, but is preferably 5 m / min or more, more preferably 10 m / min or more, and preferably 30 m because the effect is more suitably obtained. / Min or less, more preferably 20 m / min or less. When it is less than 5 m / min and when it exceeds 30 m / min, it becomes difficult to apply a sealant material having a uniform thickness.

Through the above steps, the sealant tire of the second embodiment can be manufactured.
Drawing 6 is an explanatory view showing typically an example of the sealant material stuck on the sealant tire of a 2nd embodiment.

The substantially string-like sealant material 20 is wound in the circumferential direction of the tire and is continuously attached in a spiral shape. One end portion in the length direction of the sealant material 20 is a wide portion 21 that is wider than a portion adjacent in the length direction. The wide portion 21 corresponds to a start portion for applying the sealant material.

The width of the wide portion of the sealant material because it (the width of the wide portion of the sealant material after coating, in FIG. 6, the length represented by W ₁₎ is not particularly limited, effects can be obtained more suitably, the wide portion (in FIG. 6, the length represented by _{W 0)} width than than of 103% of more, more preferably 110%, more preferably more than 120%. If it is less than 103%, the effect of providing the wide portion may not be sufficiently obtained. Further, the width of the wide portion of the sealant material is preferably 210% or less of the width other than the wide portion, more preferably 180% or less, and still more preferably 160% or less. If it exceeds 210%, it is necessary to make the tip of the nozzle excessively close to the inner peripheral surface of the tire in order to form a wide portion, so that the sealant material tends to adhere to the nozzle and the frequency of cleaning the nozzle may increase. There is. In addition, the weight balance of the tire may be lost.

In addition, although it is preferable that the width | variety of the wide part of sealant material is substantially constant in a length direction, there may be a location which is not substantially constant. For example, the wide portion may have a shape in which the width of the pasting start portion is the widest and the width becomes narrower in the length direction. Here, in this specification, when the width is substantially constant, the fluctuation of the width is 90 to 110% (preferably 97 to 103%, more preferably 98 to 102%, and further preferably 99 to 101%). It means to fit.

The length of the wide portion of the sealant material (the length of the wide portion of the sealant material after coating, in FIG. 6, the length shown by L ₁₎ because it is not particularly limited, effects can be obtained more suitably, Preferably it is less than 650 mm, More preferably, it is less than 500 mm, More preferably, it is less than 350 mm, Most preferably, it is less than 200 mm. If it is 650 mm or more, the time during which the tip of the nozzle is brought close to the inner peripheral surface of the tire becomes long, so that the sealant material tends to adhere to the nozzle and the frequency of cleaning the nozzle may increase. In addition, the weight balance of the tire may be lost. In addition, although the length of the wide part of a sealant material is so preferable that it is short, about 10 mm is a limit, when controlling the distance of the internal peripheral surface of a tire and the front-end | tip of a nozzle.

Wide portion other than the width of the sealant material because it (the width of the non-wide portion of the sealant material after coating, in FIG. 6, the length represented by W ₀₎ is not particularly limited, effects can be obtained more suitably, Preferably it is 0.8 mm or more, More preferably, it is 1.3 mm or more, More preferably, it is 1.5 mm or more. If it is less than 0.8 mm, the number of times the sealant material is wound around the inner peripheral surface of the tire increases, and the production efficiency may be reduced. Further, the width of the sealant material other than the wide portion is preferably 18 mm or less, more preferably 13 mm or less, still more preferably 9.0 mm or less, particularly preferably 7.0 mm or less, most preferably 6.0 mm or less, and most preferably. Is 5.0 mm or less. When it exceeds 18 mm, there is a possibility that weight imbalance tends to occur. W ₀ is preferably the same as W described above.

In addition, although it is preferable that widths other than the wide part of a sealant material are substantially constant in a length direction, there may be a location which is not substantially constant.

The width of the region where the sealant material is affixed (hereinafter also referred to as the width of the affixed region and the width of the sealant layer, the length represented by W ₁ + 6 × W ₀ in FIG. 6) is not particularly limited. 80% or more of the tread ground contact width is preferable, 90% or more is more preferable, 100% or more is further preferable, 120% or less is preferable, and 110% or less is more preferable.

The width of the sealant layer is preferably 85 to 115%, more preferably 95 to 105% of the tire breaker width (the length of the breaker in the tire width direction) because the effect can be obtained more suitably. More preferred.

In the sealant tire of the second embodiment, the sealant material is preferably pasted so as not to overlap in the width direction, and more preferably pasted without a gap.

In the sealant tire according to the second embodiment, the other end portion in the length direction of the sealant material (the end portion corresponding to the pasting end portion) is also a wider portion that is wider than the portion adjacent in the length direction. It may be.

The thickness of the sealant material (the thickness of the sealant material after application, the thickness of the sealant layer, the length indicated by D in FIG. 8) is not particularly limited, but is preferable because the effect is more suitably obtained. Is 1.0 mm or more, more preferably 1.5 mm or more, further preferably 2.0 mm or more, particularly preferably 2.5 mm or more, preferably 10 mm or less, more preferably 8.0 mm or less, still more preferably It is 5.0 mm or less. When it is less than 1.0 mm, it is difficult to reliably close the puncture hole when the tire is punctured. Moreover, even if it exceeds 10 mm, the effect of closing the puncture hole does not change so much and the weight of the tire increases, which is not preferable.

It is preferable that the thickness of the sealant material (the thickness of the sealant material after application, the thickness of the sealant layer) is substantially constant. Thereby, the deterioration of the uniformity of a tire can be prevented more, and the sealant tire more excellent in weight balance can be manufactured.

The thickness of the sealant material (the thickness of the sealant material after application, the thickness of the sealant layer, the length indicated by D in FIG. 8) and the width other than the wide portion of the sealant material (the width of the sealant material after application) part than the width, in FIG. 6, the ratio of the length) represented by W ₀ (width other than the wide portion of the thickness / sealant material of sealant material) is preferably 0.6 to 1.4, more preferably It is 0.7 to 1.3, more preferably 0.8 to 1.2, and particularly preferably 0.9 to 1.1. As the ratio is closer to 1.0, the shape of the sealant material becomes an ideal string shape, and a sealant tire having a high sealing property can be manufactured with higher productivity.

The cross-sectional area of the sealant material (the cross-sectional area of the sealant material after application, in FIG. 8, the area calculated by D × W) is preferably 0.8 mm ² or more, because the effect is more suitably obtained. preferably 1.95 mm ² or more, more preferably 3.0 mm ² or more, particularly preferably 3.75 mm ² or more, preferably 180 mm ² or less, more preferably 104 mm ² or less, more preferably 45 mm ² or less, particularly preferably Is 35 mm ² or less, most preferably 25 mm ² or less.

In the second embodiment, even when the viscosity of the sealant material is within the above range, in particular, even if the viscosity is relatively high, the width of the sealant material corresponding to the application start portion is widened to bond the portion. The force can be improved, and the sealant material can be prevented from peeling off at the portion.

The sealant tire of the second embodiment is preferably manufactured by the above manufacturing method, but may be manufactured by any other suitable manufacturing method as long as at least one end of the sealant material can be a wide portion. Also good.

In the above description, particularly in the description of the first embodiment, the case where the non-contact displacement sensor is used when the sealant material is applied to the inner peripheral surface of the tire has been described. Alternatively, the sealant material may be applied to the inner peripheral surface of the tire by controlling the movement of the nozzle and / or the tire based on the coordinate values input in advance.

A sealant tire having a sealant layer on the inner side in the tire radial direction of the inner liner can be manufactured by the above-described manufacturing method or the like. In particular, the sealant layer is coated with the sealant material on the inner surface of the vulcanized tire because it is less likely to cause problems due to the flow of the sealant material, and can be handled by programming even if the tire size changes. It is preferable that it is formed by the manufacturing method. In addition, because the sealant material is easy to handle and has high productivity, it is formed by a manufacturing method in which the sealant material, which is prepared sequentially by mixing raw materials containing a cross-linking agent with a continuous kneader, is sequentially applied to the inner peripheral surface of the tire. It is preferred that

The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

The various chemicals used in the examples are described below.
Butyl rubber: Regular butyl 065 (manufactured by Nippon Butyl Co., Ltd., Mooney viscosity ML1 + 8 = 32 at 125 ° C.)
Liquid polybutene: liquid polybutene A (Nippon Polybutene HV300 (JX Nippon Oil & Energy Ltd., dynamic viscosity 590 mm ² / s in kinematic viscosity 26,000mm ² / s, 100 ℃ at 40 ° C., a number average molecular weight 1,400)) and , liquid polybutene B (Nisseki polybutene HV1900 (JX Nippon Oil & energy Ltd., dynamic viscosity 3,710mm ² / s in kinematic viscosity 160,000mm ² / s, 100 ℃ at 40 ° C., a number average molecular weight 2,900)) And carbon black: N330 (manufactured by Cabot Japan Ltd., HAF grade, DBP oil absorption 102 ml / 100 g)
Crosslinking aid: Balnock GM (Ouchi Shinsei Chemical Co., Ltd., p-benzoquinone dioxime)
Cross-linking agent: Niper NS (manufactured by NOF Corporation, dibenzoyl peroxide (40% diluted product, dibenzoyl peroxide: 40% dibutyl phthalate: 48%), compounding amount in Table 1 is pure benzoyl peroxide amount)

(Example)
<Manufacture of sealant tires>
In accordance with the formulation in Table 1, butyl rubber, carbon black and crosslinking aid are supplied from the upstream supply port of the twin-screw kneading extruder, liquid polybutene B is supplied from the midstream supply port, and liquid polybutene A and crosslinking agent are supplied from the downstream supply port. The mixture was kneaded under conditions of barrel temperature 100 ° C. and 200 rpm to prepare a sealant material. In addition, about liquid polybutene, 50 degreeC liquid polybutene was supplied from the supply port.
(Kneading time of each material)
Mixing time of butyl rubber, carbon black and crosslinking aid: 2 minutes Mixing time of liquid polybutene B: 2 minutes Mixing time of liquid polybutene A and crosslinking agent: 1.5 minutes

Tire (215 / 55R17, 94W, rim: 17X8J, cavity cross-sectional area when assembled with tire rim: 194 cm ² , vulcanized, tire rotation speed: 12 m / min, preheating temperature: 40 ° C., tire breaker Sealant material (temperature: 100 ° C), which is prepared sequentially so that the width of the pasting region is 180 mm, with the sealant material (viscosity 10000 Pa · s (40 ° C), approximately string-like shape, width 4 mm) on the width: 180 mm) The first sealant layer was formed by extruding from a biaxial kneading extruder and continuously sticking to the inner peripheral surface of the tire in a spiral manner according to FIGS. Further, a sealant material was attached to the inside of the formed sealant layer in the tire radial direction by the same operation to form a second sealant layer.
The width of the sealant material was adjusted so as to be substantially constant in the length direction. Further, the thickness of the sealant layer was adjusted so as to have the values shown in Table 2.
Total volume of tire lumen: 36600 cm ³

(Comparative example)
In Comparative Example 1, a sealant layer is not formed.
Comparative Examples 2 and 3 were produced under the same conditions as in the Examples except that the sealant layer was composed of only one layer.
In Comparative Example 4, the arrangement order of the sealant layer is reversed from that in Example 1.

The obtained sealant tire was evaluated as follows.

<Test 1 (initial sealability)>
The initial internal pressure of the tire was set to 250 kPa, and at an atmospheric temperature of 25 ° C., 20 nails in which the length of a JIS N150 nail (cylinder diameter 5.2 mm) was processed to 50 mm were driven to the head of the tire block and left for 1 hour. Later, the nails were removed, and the tires were left at an ambient temperature of 25 ° C. for a whole day, and soap water was applied to check the number of nail holes where no air leaked.
The larger the index, the better the initial sealability. If it is 14 or more, it is good.

<Test 2 (sealing after running)>
An initial internal pressure of the tire was set to 250 kPa, 20 nails in which the length of a JIS N150 nail (cylinder diameter 5.2 mm) was processed to 50 mm were driven into the block portion of the tire to the head at an atmospheric temperature of 25 ° C., and the atmospheric temperature was 25 ° C. After running the 750 km drum under the conditions of speed 150 km / h and load 4.2 kN, the nails were removed and the tires were left at an ambient temperature of 25 ° C. with soapy water and air leaked. The number of nail holes not confirmed.
The larger the index, the better the sealing performance after running. If it is 14 or more, it is good.

<Test 3 (Sealability at low temperature)>
After running the drum under the same conditions as in Test 2, leave the tires in a room with an ambient temperature of -10 ° C for 12 hours, remove the nail, and then add soapy water to check the number of nail holes where no air leaks. did.
The larger the index, the better the sealing performance at low temperatures. If it is 14 or more, it is good.

A pneumatic tire having a sealant layer on the inner radial direction of the inner liner, wherein the sealant layer has a configuration in which a first sealant layer and a second sealant layer are laminated in this order from the inner liner side, The pneumatic tire of the example in which the viscosity of the first sealant layer is lower than the viscosity of the second sealant layer has good initial sealing performance, sealing performance after running, and sealing performance at low temperature. It was.

DESCRIPTION OF SYMBOLS 10 Tire 11 Tire inner peripheral surface 14 Tread part 15 Carcass 16 Breaker 17 Band 19 Inner liner 20 Sealant material 21 Wide part 22 Sealant layer 22a First sealant layer 22b Second sealant layer 30 Nozzle 31 Nozzle tip 40 Non-contact displacement Sensor 50 Rotation drive device 60 Twin-screw kneading extruder 61 (61a 61b 61c) Feed port 62 Distance A between the inner circumferential surface of the material feeders d, d ₀ , d ₁ and d ₂ and the tip of the nozzle A Nail

Claims (5)

A pneumatic tire having a sealant layer on the inner side in the tire radial direction of the inner liner,
The sealant layer has a configuration in which a first sealant layer and a second sealant layer are laminated in this order from the inner liner side,
A pneumatic tire in which the viscosity of the first sealant layer is lower than the viscosity of the second sealant layer. The pneumatic tire according to claim 1, wherein the second sealant layer is thicker than the first sealant layer. The pneumatic tire according to claim 1 or 2, wherein the first sealant layer and the second sealant layer have a thickness of 1 to 5 mm. The pneumatic tire according to any one of claims 1 to 3, wherein a total thickness of the first sealant layer and the second sealant layer is 7 mm or less. The first sealant layer contains 200 parts by mass or more of liquid polybutene, 40 parts by mass or less of carbon black, and 15 parts by mass or less of a crosslinking agent with respect to 100 parts by mass of the rubber component, and the 0 ° C. viscosity is 35 kPa · composed of a sealant material having a viscosity of less than s and a viscosity at 95 ° C. of less than 6 kPa · s,
The second sealant layer contains 250 parts by mass or less of liquid polybutene, 40 parts by mass or more of carbon black, and 15 parts by mass or more of a crosslinking agent with respect to 100 parts by mass of the rubber component, and the 0 ° C. viscosity is 35 kPa · s or more. The pneumatic tire according to any one of claims 1 to 4, comprising a sealant material having a viscosity at 95 ° C of 6 kPa · s or more.

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