JP2018003007A - Rubber composition for sealant material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for a sealant material having excellent low temperature sealing property, and a pneumatic tire (sealant tire) using the same. SOLUTION: A rubber composition for a sealant material having an elongation at break of 800% or more when a tensile test is performed under the conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C. [Selection diagram] FIG. 7

Description

The present invention relates to a rubber composition for a sealant material and a pneumatic tire using the same.

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 the inner surface of the tire is known. In the sealant tire, a hole formed at the time of puncture is automatically closed by the sealant material, and various studies have been made on the sealant material.

However, as a result of the study by the present inventors, it has been found that the conventional sealant material has room for improvement in low-temperature sealability.
An object of the present invention is to solve the above-mentioned problems and to provide a rubber composition for a sealant material excellent in low-temperature sealability and a pneumatic tire (sealant tire) using the same.

As a result of intensive studies on the low-temperature sealability (sealability at −20 ° C.) of the sealant material, the present inventor has conceived that the low-temperature tensile properties (elongation at break) of the sealant material are important. Then, although the tensile test was performed and evaluated under the conditions of test temperature -20 degreeC, even if it was highly evaluated by this test, there existed some things with low-temperature sealing property not favorable. As a result of intensive studies, the tensile speed at the time of performing the tensile test was 500 mm / min, which is conventionally used. However, the tensile speed was set to a very high speed of 3.0 m / s. It was found that there is a high correlation between the evaluation result of the tensile test and the low-temperature sealability. That is, it has been found that for low temperature sealability, the elongation of a sealant material against high-speed tension at low temperatures is important. Furthermore, as a result of intensive studies, the present inventor has found that when the tensile test is performed under the conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C., the elongation at break is 800% or more, a good low temperature The inventors have found that sealing properties can be obtained and completed the present invention.
That is, the present invention relates to a rubber composition for a sealant material having an elongation at break of 800% or more when a tensile test is performed under conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C.

The rubber composition for sealant material preferably has an elongation at break of 850% or more and 2000% or less when a tensile test is performed under conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C.

The rubber composition for sealant material preferably has an elongation at break of 900% or more and 1800% or less when a tensile test is performed under the conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C.

The rubber composition for a sealant material preferably contains 100 parts by mass or more of a liquid polymer with respect to 100 parts by mass of the rubber component.

The rubber composition for a sealant material preferably contains 8 parts by mass or less of an organic peroxide and 8 parts by mass or less of a crosslinking aid with respect to 100 parts by mass of the rubber component.

The rubber composition for a sealant material preferably contains 15 parts by mass or more of a plasticizer with respect to 100 parts by mass of the rubber component.

The present invention also relates to a pneumatic tire (sealant tire) having a sealant layer produced using the rubber composition.

The rubber composition for sealant material of the present invention has an elongation at break of 800% or more when subjected to a tensile test under the conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C. An excellent sealant material can be provided.

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.

The rubber composition for sealant material (sealant material) of the present invention has an elongation at break of 800% or more when subjected to a tensile test under the conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C.

Thus, sufficient elongation for high-speed tension at a low temperature is achieved by setting the elongation at break when the tensile test is performed under the conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C. to a specific value or more. Can be obtained, and a sealant material excellent in low-temperature sealability can be provided. By obtaining sufficient elongation for high-speed tension at low temperature, when the nail is pierced at low temperature, the sealant material can follow the nail.

The rubber composition of the present invention has an elongation at break of 800% or more, preferably 850% or more, more preferably when a tensile test is performed under the conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C. Is 900% or more, more preferably 950% or more. The upper limit is not particularly limited, but is preferably 2000% or less, more preferably 1800% or less, because there is a concern that rubber flow may occur when elongation becomes too large.
In this specification, the elongation at break when performing a tensile test under the conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C. is JIS K6251: 2010 “vulcanized rubber and thermoplastic rubber-tensile. In accordance with “How to Obtain Properties”, a No. 3 dumbbell-shaped test piece made of a rubber composition (crosslinked rubber composition) was used for tensile testing under the conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C. It is a value obtained by carrying out a test and measuring the elongation at break (tensile elongation; EB [%]), and can be specifically measured by the method described in the examples described later. When punching into the No. 3 dumbbell mold, it sticks softly at room temperature, so it is cooled to −30 ° C. and then punched.

In the above rubber composition, the specific elongation at break when a tensile test is conducted under the conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C. is a predetermined composition described later for the rubber composition. However, the present invention is not limited to this, and for the following reasons, the elongation at break when performing a tensile test under the conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C. is within a predetermined range. A person skilled in the art can understand how to prepare a rubber composition of the present invention.

Regarding the rubber composition, the elongation at break (tensile elongation) when a tensile test is performed is related to the molecular mobility of the rubber, and the degree of crosslinking of the rubber composition is high. When the density is high, the molecular mobility of the rubber decreases and the tensile elongation tends to decrease. On the other hand, when the degree of crosslinking of the rubber composition is low or the density of the rubber in the rubber composition is low, the molecular mobility of the rubber tends to increase and the tensile elongation tends to increase. These are common technical knowledge in the chemical field. In particular, when the tensile test is performed under conditions of a tensile speed of 3.0 m / s, a test temperature of −20 ° C., and a high temperature and a low temperature, the molecular mobility of the rubber is significantly affected by the tensile elongation.
Here, the degree of cross-linking of the rubber composition is such that the cross-linking point can be adjusted by adjusting the polymer component to be cross-linked, the type of cross-linking component such as a cross-linking agent or a cross-linking aid, or adjusting the blending amount. It is possible to control the amount. Moreover, about the density of rubber | gum in a rubber composition, it is possible to control the density of rubber | gum in a rubber composition by adjusting the kind and compounding quantity of components other than rubber | gum, such as a liquid component. This is also common technical knowledge in the chemical field. And furthermore, if the blending amount of the crosslinking component decreases, the amount of crosslinking points decreases, the degree of crosslinking of the rubber composition decreases, the tensile elongation increases, and if the blending amount of the liquid component increases, It is common technical knowledge in the field of sealant materials that the rubber density in the rubber composition is lowered and the tensile elongation is increased.
From these facts, those skilled in the art will be able to perform the tensile test under the conditions that the rubber composition has a tensile speed of 3.0 m / s and a test temperature of −20 ° C., no matter what components are added to the rubber composition. It is possible to adjust the elongation at break when the test is performed to a predetermined range.
Therefore, it is possible to prepare the rubber composition of the present invention in which the elongation at break when a tensile test is conducted under the conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C. is within a predetermined range.

The specific elongation at break when a tensile test is performed under the conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C. is, for example, the types of rubber components and reinforcing agents blended in the rubber composition, for example. Types and blending amounts of (inorganic fillers), crosslinking agents, crosslinking aids and blending amounts, and liquid polymers and plasticizers when blending liquid polymers and plasticizers with rubber compositions It can be provided by adjusting.

More specifically, when the blending amount of the liquid polymer and the plasticizer is increased, the elongation at break can be increased, and the blending amount of the rubber component, the reinforcing agent (inorganic filler), the crosslinking agent, and the crosslinking aid is increased. And the elongation at break can be reduced.

Specifically, as a sealant material described in detail later, the content of a liquid polymer (preferably a liquid polymer having a relatively high molecular weight (having kinematic viscosity described later)) is set to a specific amount or more, an organic peroxide, The elongation at break can be increased by setting the content of the crosslinking aid to a specific amount or less and setting the plasticizer amount (oil amount) to a specific amount or more.

The rubber composition for sealant tires (sealant material) of the present invention is applied to a portion of the tire inner surface that may be punctured, such as a tread of a sealant tire. While explaining, the sealant material will be explained.

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.

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 polymer, 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.

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.

The butyl rubber is preferably a halogenated butyl rubber. By using halogenated butyl rubber, it is possible to contribute to increasing the elongation at break, and a sealant material having good low-temperature sealability can be obtained more suitably. Furthermore, among the halogenated butyl rubbers, brominated butyl rubber is particularly preferable because the rubber flow can be prevented by promoting the crosslinking reaction.

When the rubber composition of the present invention contains a halogenated butyl rubber and an organic peroxide (preferably also a crosslinking aid), the crosslinking proceeds rapidly, so that the kneading time is relatively short. It is suitable to be prepared using a continuous kneader such as a machine. Thereby, problems such as overvulcanization can be suppressed, and better low-temperature sealing performance can be obtained.

The Mooney viscosity ML1 + 8 at 125 ° C. is preferably 20 to 60, and more preferably 40 to 60, from the viewpoint that the butyl rubber can ensure the fluidity of the sealant material more suitably. If it is less than 20, the fluidity may decrease, and if it exceeds 60, the sealing property may decrease. By using the halogenated butyl rubber having the above viscosity, the rubber flow can be prevented by the high viscosity of the halogenated butyl rubber and the high cross-linking density by promoting the cross-linking reaction by the halogenated butyl rubber. As a result, when applying the sealant material, The sealant material can be applied to the inner peripheral surface of the tire without worrying about the rubber flow. Also, good low temperature sealing properties can be obtained.

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.

The halogen content of the halogenated butyl rubber is preferably 0.1 to 5.0% by mass, more preferably 0.5 to 4.0% by mass. As a result, a more preferable effect of promoting the crosslinking reaction can be obtained, which can contribute to increasing the elongation at break, and a sealant material having a good low temperature sealing property can be obtained more suitably.
The halogen content can be measured by solution NMR.

The content of the butyl rubber is preferably 80% by mass or more, more preferably 90% by mass or more, and may be 100% by mass in 100% by mass of the rubber component. Thereby, it can contribute to increasing the said elongation at the time of a fracture | rupture, and a sealant material with favorable low temperature sealing property is obtained more suitably.

In addition to the above 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) ), Other components such as diene rubbers such as chloroprene rubber (CR) and acrylonitrile butadiene rubber (NBR) may be used in combination.

The sealant material preferably contains a liquid polymer.

Liquid polybutene, liquid polyisobutene, liquid polyisoprene, liquid polybutadiene, liquid poly α-olefin, liquid polyisobutylene, liquid ethylene α-olefin copolymer, liquid ethylene propylene copolymer, liquid ethylene butylene as the liquid polymer in the sealant material A copolymer 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, only 1 type may be used and 2 or more types may be used together.

The kinematic viscosity at 100 ° C. of the liquid polymer such as liquid polybutene is preferably 3540 mm ² / s or more, more preferably 3600 mm ² / s or more, and further 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.
Kinematic viscosity at the 100 ° C. is preferably 4010mm ² / s or less, more preferably 3900 mm ² / s, more preferably not more than 3800 mm ² / s. If it exceeds 4010 mm ² / s, the sealing property may be deteriorated.

The kinematic viscosity at 40 ° C. of the liquid polymer 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.

The content of the liquid polymer is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, and still more preferably 120 parts by mass or more with respect to 100 parts by mass of the rubber component. If it is less than 50 mass parts, there exists a possibility that adhesiveness may fall. Further, the elongation at break may not be sufficiently increased. The content is preferably 400 parts by mass or less, more preferably 300 parts by mass or less, still more preferably 250 parts by mass or less, and particularly preferably 200 parts by mass or less. If it exceeds 400 parts by mass, the sealant material may flow.

Especially, as said liquid polymer, it is preferable to use only 1 type of liquid polymer whose kinematic viscosity in 100 degreeC and kinematic viscosity in 40 degreeC are in the said range by the content mentioned above. By using a liquid polymer of such kind and content, it is possible to contribute to increasing the elongation at break, and a sealant material having good low temperature sealability can be obtained more suitably.
Specifically, 100 parts by mass (preferably 120 parts by mass) or more of the liquid polymer is blended with 100 parts by mass of the rubber component. Furthermore, the liquid polymer has a kinematic viscosity at 100 ° C. and a kinematic viscosity at 40 ° C. By using a liquid polymer having a value within the above range, the elongation at break can be suitably made to be a specific value or more.

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.

The content of the organic peroxide (crosslinking agent) is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and further preferably 3 parts by mass or more with respect to 100 parts by mass of the rubber component. If it is less than 0.5 part by mass, the crosslinking density is low, and the elongation at break may not be sufficiently increased. The content is preferably 8 parts by mass or less, more preferably 5 parts by mass or less. If the amount exceeds 8 parts by mass, the crosslink density increases and becomes hard, so that the elongation at break may not be sufficiently increased.
By blending 8 parts by mass (preferably 5 parts by mass) or less of the organic peroxide with respect to 100 parts by mass of the rubber component, the elongation at break can be suitably set to a specific value or more.

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-nitrobenzoate), p-quinone dioxime Di (m-nitrobenzoate), 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.

The content of the crosslinking aid such as a quinonedioxime compound is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and further preferably 3 parts by mass or more with respect to 100 parts by mass of the rubber component. If it is less than 0.5 parts by mass, the elongation at break may not be sufficiently increased. The content is preferably 8 parts by mass or less, more preferably 5 parts by mass or less. If the amount exceeds 8 parts by mass, the crosslink density increases and becomes hard, so that the elongation at break may not be sufficiently increased.
By blending 8 parts by mass (preferably 5 parts by mass) or less of a crosslinking aid with respect to 100 parts by mass of the rubber component, the elongation at break can be suitably set to a specific value or more.

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.

The content of the inorganic filler is preferably 1 part by mass or more, more preferably 10 parts by mass or more with respect to 100 parts by mass of the rubber component. If the amount is less than 1 part by mass, the sealing property may be deteriorated due to deterioration by ultraviolet rays. The content is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and still more preferably 30 parts by mass or less. If it exceeds 50 parts by mass, the viscosity of the sealant material becomes too high, and the sealing performance may be deteriorated.

From the viewpoint of preventing deterioration due to ultraviolet rays, carbon black is preferred as the inorganic filler. In this case, the content of carbon black is preferably 1 part by mass or more, more preferably 10 parts by mass or more with respect to 100 parts by mass of the rubber component. If the amount is less than 1 part by mass, the sealing property may be deteriorated due to deterioration by ultraviolet rays. The content is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and still more preferably 25 parts by mass or less. If it exceeds 50 parts by mass, the viscosity of the sealant material becomes too high, and the sealing performance may be deteriorated.

As the plasticizer (oil), dioctyl phthalate (DOP) is preferable because the softening point temperature is preferably low in order to maintain a low temperature softening state.
In the present specification, the plasticizer does not include the liquid polymer.

The content of the plasticizer is preferably 15 parts by mass or more, more preferably 20 parts by mass or more with respect to 100 parts by mass of the rubber component. If it is less than 15 parts by mass, the elongation at break may not be sufficiently increased. The content is preferably 40 parts by mass or less, more preferably 30 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.
By blending 15 parts by mass (preferably 20 parts by mass) or more of the plasticizer with respect to 100 parts by mass of the rubber component, the elongation at break can be suitably set to a specific value or more.

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, and a crosslinking aid are blended with a rubber component containing a butyl rubber is preferable.

Adhesiveness, sealability, fluidity, and workability are improved in a well-balanced manner by using a butyl rubber blended with a liquid polymer such as liquid polybutene as the sealant material. This is because a liquid polymer component is introduced into an organic peroxide cross-linking system using butyl rubber as a rubber component to provide adhesion, and a liquid polymer or solid butyl rubber provides a sealant material for high speed running. By suppressing the flow, the adhesiveness, sealability, fluidity and processability are improved in a well-balanced manner.

Moreover, as a sealant material, since it is excellent in fluidity | liquidity and deterioration resistance, what contains the rubber component containing halogenated butyl rubber and an organic peroxide is also preferable.

The viscosity (40 ° C.) of the sealant material is not particularly limited. However, when the sealant material is applied to the inner peripheral surface of the tire, the sealant material suitably holds a substantially string-like shape. From the viewpoint, it is preferably 3000 Pa · s or more, more preferably 5000 Pa · s or more, and preferably 70000 Pa · s or less, more preferably 50000 Pa · s or less. If it is less than 3000 Pa · s, the sealant material may flow when the tire is stopped after application of the sealant material, and the film thickness may not be maintained. Moreover, when it exceeds 70000 Pa.s, it becomes difficult to discharge the sealant material from the nozzle.
The viscosity of the sealant material is a value measured by a rotary viscometer under the condition of 40 ° C. according to JIS K 6833.

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 kneading extruder) is used, the sealant material is a continuous kneader (especially a biaxial kneading extruder) having at least three supply ports, and the continuous kneader (especially two A rubber component such as butyl rubber, an inorganic filler, and a crosslinking aid are supplied from the supply port on the upstream side of the shaft kneading extruder, and the liquid polymer is supplied from the supply port on the middle stream side, and the supply on the downstream side It is preferably prepared by supplying an organic peroxide and a plasticizer from the mouth and 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 viewpoint of ease of mixing, extrudability, and control of the curing acceleration rate. .

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 (controlling) 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. Good fluidity can be imparted to 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 pressure in the continuous kneader (particularly, the biaxial kneader / extruder) is preferably 1.0 to 10.0 MPa from the viewpoint of sufficient mixing property, plasticity, and curing acceleration rate control.

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. While traversing and / or moving up and down while rotating the tire with a tire driving device (moving in the width direction and / or radial direction of the tire), 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 sticking the sealant material spirally on the inner peripheral surface of the tire. 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. The sealant layer may be formed by laminating sealant materials, but preferably comprises a single layer of sealant material.

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. Moreover, since it is sufficient to apply one layer without laminating several layers of the sealant material, a sealant tire can be manufactured with higher productivity.
Thus, as the sealant material, the rubber composition for sealant material (sealant material) of the present invention having the specific elongation at break described above is used, and the substantially string-like sealant material is continuously spiraled into the tire. By forming the sealant layer by coating on the inner peripheral surface of the tire, a pneumatic tire (sealant tire) having a sealant layer excellent in low-temperature sealability can be stably produced with high productivity.

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, 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. 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 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 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.

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.
Brominated butyl rubber: Bromobutyl 2255 (manufactured by ExxonMobil, Mooney viscosity ML1 + 8 = 46 at 125 ° C., halogen content: 2.0 mass%)
Non-halogenated butyl rubber: Butyl 268 (manufactured by ExxonMobil, Mooney viscosity ML1 + 8 = 51 at 125 ° C., halogen content: 0% by mass)
Natural rubber: TSR20
Liquid polybutene: Nisseki Polybutene HV1900 (JX Nippon Oil & Energy Corporation, kinematic viscosity at kinematic viscosity 160,000mm ² / s, 100 ℃ at 40 ℃ 3,710mm ² / s, a number average molecular weight 2,900)
Polyisobutylene: Tetrax 3T (manufactured by JX Nippon Oil & Energy Corporation, kinematic viscosity at 200 ° C. 6,500 mm ² / s, weight average molecular weight 49,000)
Carbon black: N330 (manufactured by Cabot Japan, HAF grade, DBP oil absorption 102 ml / 100 g)
Silica: ULTRASIL VN3 (N ₂ SA: 175 m ² / g) manufactured by Evonik
Plasticizer (oil): Dioctyl phthalate (DOP) manufactured by Taoka Chemical Co., Ltd.
Processing aid: Stractol EF44 (fatty acid metal salt) manufactured by Schill & Seilacher
Crosslinking aid: Balnock GM (Ouchi Shinsei Chemical Co., Ltd., p-benzoquinone dioxime)
Zinc oxide: Zinc oxide type 2 cross-linking agent manufactured by Mitsui Mining & Smelting Co., Ltd .: Niper NS (manufactured by NOF Corporation, dibenzoyl peroxide (40% diluted product, dibenzoyl peroxide: 40% dibutyl phthalate: 48%) ), Table 1 compounding amount is pure benzoyl peroxide amount)
Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Co., Ltd.

<Manufacture of sealant tires>
In accordance with the composition of Table 1, butyl rubber or natural rubber, carbon black or silica, and a crosslinking aid or zinc oxide are supplied downstream from the upstream supply port of the twin-screw kneading extruder, and liquid polybutene or polyisobutylene is supplied downstream from the midstream supply port. A plasticizer or a processing aid and a crosslinking agent or sulfur were introduced from the mouth, and kneaded under conditions of a barrel temperature of 100 ° C., a screw rotation speed of 200 rpm, and a pressure of 5.0 MPa 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 or natural rubber, carbon black or silica and crosslinking aid or zinc oxide: 2 minutes Mixing time of liquid polybutene or polyisobutylene: 2 minutes Mixing time of plasticizer or processing aid and crosslinking agent or sulfur: 1. 5 minutes

Next, a sealant material prepared in sequence from the nozzle directly connected to the discharge port of the twin-screw kneading extruder and having the tip installed on the inner surface of the tire to the inner surface of the tire rotating in the circumferential direction (preheating temperature: 40 ° C.) (Temperature 100 ° C., viscosity 20000 Pa · s (40 ° C.), substantially string-like shape) was discharged and continuously applied spirally on the inner peripheral surface of the tire according to FIGS. Moreover, the viscosity of the sealant material was measured with a rotary viscometer in accordance with JIS K 6833 under the condition of 40 ° C.

1. High speed tensile test 195 / 65R15 size vulcanized tire inner surface (circumferential direction is the whole area, width direction is from the breaker edge part to the other breaker edge part) by applying a sealant material with a thickness of 3mm to form a sealant layer Formed. Next, a No. 3 dumbbell-shaped test piece was prepared from the formed sealant layer, and the test piece was used to obtain a tensile speed of 3 in accordance with JIS K6251: 2010 “vulcanized rubber and thermoplastic rubber—determining tensile properties”. A tensile test was performed under the conditions of 0.0 m / s and a test temperature of −20 ° C., and the elongation at break (tensile elongation; EB [%]) was measured.
When punching into the No. 3 dumbbell mold, it was softly adhered at room temperature. Therefore, the punching was performed after cooling to −30 ° C. Further, sampling from the sealant layer formed on the inner surface of the tire was also performed after cooling to -30 ° C.

2. Low-speed tensile test A tensile test was performed in the same manner as the high-speed tensile test except that the tensile speed was 500 mm / min, and the elongation at break (tensile elongation; EB [%]) was measured.

3. Low-temperature sealability evaluation A 195 / 65R15 size vulcanized tire inner surface (circumferential direction is the whole area, width direction is from the breaker edge part to the other breaker edge part) is applied with a sealant material at a thickness of 3 mm, and the internal pressure is 230 kPa. A nail having a diameter of 4 mm and a length of 50 mm was hit in an environment filled with air at −20 ° C., and the internal pressure immediately after the nail was pulled out after 3 hours was measured. The low temperature sealing property (low temperature air sealing property) of each example was indicated by an index according to the following formula, using Comparative Example 1 as a reference. The larger the low temperature sealability index, the lower the internal pressure, and the better the low temperature sealability (low temperature air sealability).
(Low-temperature sealability index) = (Internal pressure in each example) / (Internal pressure in Comparative Example 1) × 100

The sealant material of the example having an elongation at break of 800% or more when the tensile test was performed under the conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C. was excellent in low-temperature sealability.

DESCRIPTION OF SYMBOLS 10 Tire 11 Tire inner peripheral surface 14 Tread part 15 Carcass 16 Breaker 17 Band 20 Sealant material 21 Wide part 30 Nozzle 31 Nozzle tip 40 Non-contact displacement sensor 50 Rotation drive device 60 Two-screw kneading extruder 61 (61a 61b 61c ) Supply port 62 The distance between the inner peripheral surface of the material feeders d, d ₀ , d ₁ and d ₂ and the tip of the nozzle

Claims (7)

A rubber composition for a sealant material having an elongation at break of 800% or more when a tensile test is performed under conditions of a tensile speed of 3.0 m / s and a test temperature of −20 ° C. The rubber composition for a sealant material according to claim 1, wherein the elongation at break is 850% or more and 2000% or less. The rubber composition for a sealant material according to claim 1, wherein the elongation at break is 900% or more and 1800% or less. The rubber composition for sealant materials according to any one of claims 1 to 3, comprising 100 parts by mass or more of a liquid polymer with respect to 100 parts by mass of the rubber component. The rubber composition for sealant materials according to any one of claims 1 to 4, comprising 8 parts by mass or less of an organic peroxide and 8 parts by mass or less of a crosslinking aid with respect to 100 parts by mass of the rubber component. The rubber composition for sealant materials according to any one of claims 1 to 5, comprising 15 parts by mass or more of a plasticizer with respect to 100 parts by mass of the rubber component. A pneumatic tire having a sealant layer produced using the rubber composition according to claim 1.

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