JP7158127B2 - pneumatic tire - Google Patents

Description

The present invention relates to pneumatic tires.

In recent years, there has been a demand for further noise reduction and quietness of automobiles. There are various types of noise generated by tires. Among them, so-called road noise, which produces a rumbling sound in the frequency range of 50 to 400 Hz when driving on a road surface, is transmitted to the interior of the vehicle and causes discomfort to passengers. There is a risk. On the other hand, Patent Document 1 discloses that the noise can be reduced by attaching a sponge with a specific sealant material to the inside of the inner liner of the tire, but it is desirable to provide another method. It is rare.

JP 2013-43643 A

An object of the present invention is to solve the above problems and to provide a pneumatic tire excellent in road noise reduction.

Conventionally, attempts have been made to provide a sound absorbing layer having a sponge such as polyurethane as a sound absorbing material in the inner cavity of a tire. We found that it can be used as a material, and completed the present invention.
That is, the present invention provides a sound absorbing layer having a three-dimensional network structure as a sound absorbing material formed by irregularly entangling a plurality of filaments of molten resin and welding the entangled portions, in a tire inner cavity. It relates to a pneumatic tire equipped.

The pneumatic tire preferably has a sealant layer inside the inner liner in the tire radial direction.

The pneumatic tire has the sound absorbing layer inside the sealant layer in the tire radial direction, the sealant layer is made of a sealant material, and the sound absorbing layer is fixed by the sealant material. is preferred.

The three-dimensional network structure preferably has an apparent density of 10 to 250 kg/m ³ .

It is preferable that the three-dimensional network structure has a cross-sectional area ratio of 5 to 70% to the inner cavity of the tire.

The resin is preferably a thermoplastic resin.

Preferably, the filars are hollow fibers.

It is preferable that the sealant layer is composed of a substantially string-shaped sealant material continuously spirally arranged along the inner peripheral surface of the tire.

In the pneumatic tire of the present invention, a sound absorbing layer having, as a sound absorbing material, a three-dimensional network structure formed by a plurality of filaments made of molten resin intertwined irregularly and the intertwined portions being welded is provided in the tire. Since it is a pneumatic tire with a cavity, it is excellent in reducing road noise.

It is explanatory drawing which shows typically an example of the coating device used with the manufacturing method of a sealant tire. 2 is an enlarged view of the vicinity of the tip of a nozzle that constitutes the coating device shown in FIG. 1. FIG. FIG. 4 is an explanatory diagram schematically showing the positional relationship of nozzles with respect to tires; FIG. 4 is an explanatory diagram schematically showing an example of a state in which a substantially string-shaped sealant material is continuously and spirally attached to the inner peripheral surface of a tire. 2 is an enlarged view of the vicinity of the tip of a nozzle that constitutes the coating device shown in FIG. 1. FIG. It is explanatory drawing which shows typically an example of the sealant material stuck on the sealant tire. It is an explanatory view showing typically an example of the manufacturing equipment used for the manufacturing method of a sealant tire. FIG. 5 is an explanatory diagram schematically showing an example of a cross section of the sealant material when the sealant material of FIG. 4 is cut along a straight line AA perpendicular to the application direction (longitudinal direction) of the sealant material. It is an explanatory view showing an example of a section of a pneumatic tire typically. It is explanatory drawing which shows an example of the cross section of a sealant tire typically. FIG. 3 is an explanatory diagram schematically showing an example of how a three-dimensional network structure is manufactured. 6 is a bottom view showing an example of the arrangement of extrusion holes 611 in the mouthpiece 610. FIG. (a) is a plan view of an outer circumference chute 631. FIG. (b) is a cross-sectional view of the outer circumference chute 631 taken along line AA. (a) and (b) are sectional views of modifications of the outer circumference chute 631. FIG.

The pneumatic tire of the present invention (hereinafter, the pneumatic tire is also simply referred to as a tire) is a three-dimensional structure formed by irregularly intertwining a plurality of filaments made of molten resin and welding the intertwined portions. The pneumatic tire is provided with a sound absorbing layer having a mesh structure as a sound absorbing material in the inner cavity of the tire. That is, because the tire inner cavity is provided with a specific three-dimensional network structure that the present inventors have discovered can be used as a sound absorbing material in the same way as sponge such as polyurethane that has been conventionally used as a sound absorbing material. , good road noise reduction is obtained.

Since the three-dimensional network structure has cavities between the entangled filaments, it is presumed that the cavities contribute to the reduction of road noise.

Further, conventionally, a sealant tire having a sealant layer in which a sealant material is applied to the inner peripheral surface of the tire is known as a pneumatic tire having a puncture prevention function. In a sealant tire, a sealant material automatically closes the hole that is formed when the tire is punctured.

As a method of manufacturing a sealant tire, an organic solvent is added to the sealant material, and the diluted sealant material that has been reduced in viscosity and is easy to handle is attached to the inner surface of the tire, and after attaching the diluted sealant material, the organic solvent is removed from the diluted sealant material. A method is known in which a base compound and a curing agent prepared in a kneading apparatus are mixed using a static mixer or a dynamic mixer to prepare a sealant material, which is then attached to the inner peripheral surface of a tire.

Patent Document 1 discloses that noise can be reduced by attaching a sponge to the inner liner of a tire using a specific sealant material. It has been found that the attached sponge can adversely affect the sealing performance. That is, if a sponge is attached as a sound absorbing material, when the sealant material flows into the punctured hole and closes the hole, the torn pieces of sponge may also flow in together with the sealant material, which is about 10%. It was found that the air seal failed with a probability of On the other hand, as a result of intensive studies, the inventors of the present invention have found that when the above-mentioned specific three-dimensional network structure is used as a sound absorbing material, the three-dimensional network structure is less susceptible to damage and does not adversely affect the sealing performance. rice field. Thus, a pneumatic tire (sealant tire) having a sound absorbing layer having a three-dimensional network structure as a sound absorbing material in the tire cavity and further having a sealant layer inside the inner liner in the tire radial direction (sealant tire) has excellent sealing performance, road noise Excellent reduction performance.

In the pneumatic tire of the present invention, a sound absorbing layer having, as a sound absorbing material, a three-dimensional network structure formed by a plurality of filaments made of molten resin intertwined irregularly and the intertwined portions being welded is provided in the tire. A pneumatic tire with a cavity.

The pneumatic tire of the present invention only needs to have the sound absorbing layer in the inner cavity of the tire, thereby obtaining good road noise reduction properties. The sound absorbing layer may or may not be fixed to the tire. If the sound absorbing layer is not fixed to the tire, the sound absorbing layer may come into contact with the inner surface of the tire or the wheel while the vehicle is running, leading to damage to the sound absorbing layer. Even if the sound absorbing layer is damaged, it does not affect the running of the vehicle, but the noise reduction effect is lowered. Therefore, it is preferable that the sound absorbing layer be fixed to the tire.

A method for fixing the sound absorbing layer to the tire is not particularly limited. For example, the sound absorbing layer may be adhered to the inner surface of the tire with an adhesive or the like, but it is preferably fixed by the sealant material constituting the sealant layer. That is, a sound absorbing layer having a three-dimensional network structure as a sound absorbing material is provided in the tire lumen, a sealant layer is provided inside the inner liner in the tire radial direction, and the sound absorbing layer is provided inside the sealant layer in the tire radial direction. A pneumatic tire (sealant tire) in which the sealant layer is made of a sealant material and the sound absorbing layer is fixed by the sealant material is excellent in sealing performance and road noise reduction performance.

Further, it is preferable that the sealant layer is formed of a substantially cord-shaped sealant material that is continuously spirally arranged along the inner peripheral surface of the tire. That is, by forming a sealant layer by applying a substantially string-shaped sealant material continuously and spirally to the inner peripheral surface of the tire, a uniform sealant layer (along the inner peripheral surface of the tire) can be obtained. A sealant layer composed of a substantially string-shaped sealant material arranged continuously in a spiral shape) can be formed on the inner peripheral surface of the tire, and a sealant tire with more excellent sealability can be manufactured stably and with high productivity. . The sealant tire obtained by this production method has a sealant layer in which the sealant material is uniform in the tire circumferential direction and the tire width direction (especially in the tire circumferential direction), and therefore has more excellent sealing properties. In addition, the tire is less likely to be out of balance due to the sealant material, and deterioration of tire uniformity can be reduced.

Furthermore, by attaching the sound absorbing layer to the sealant layer having a uniform sealant material using the adhesiveness of the sealant material, good road noise reduction can be imparted without deteriorating the sealing performance. . Further, by attaching the sound absorbing layer to the sealant layer in which the sealant material is uniform, better road noise reduction can be obtained. In this way, the sealant layer is composed of a substantially string-shaped sealant material that is continuously spirally arranged along the inner peripheral surface of the tire, and the sound absorbing layer is fixed by the sealant material. (The sound absorbing layer is affixed by the sealant material applied to the inner peripheral surface of the tire), so that each improvement effect obtained by providing the sealant layer and the sound absorbing layer can be maximized. , sealant tires with excellent sealing properties and road noise reduction properties can be stably manufactured with high productivity. Also, by providing the sound absorbing layer, adhesion of foreign matter to the sealant layer can be suppressed.

In particular, by using a sealant material having a composition described below as the sealant material, the effect can be obtained more preferably. Furthermore, with the sealant material having the composition described below, even in a low-temperature environment, the sealant material automatically closes a hole formed when the tire is punctured.

In addition, since the sealant material having the composition described later has low fluidity even at high temperatures, impregnation of the sound absorbing layer with the sealant material can be suppressed. Therefore, there is no need to provide a film or layer on the sound absorbing layer for the purpose of preventing impregnation of the sealant material, and a sound absorbing layer composed only of a three-dimensional network structure can be used, resulting in higher road noise reduction performance. . In this case, the three-dimensional network structure and the sealant layer are in contact with each other without a film or layer between the three-dimensional network structure and the sealant layer.
In addition, impregnation of the sound absorbing layer with the sealant material deteriorates the road noise reduction performance. A sufficient effect of improving the noise reduction property can be obtained.

As the sealant material having the composition described later, specifically, an organic peroxide is used as a cross-linking agent, or a rubber component containing a butyl rubber is blended with a liquid polymer such as liquid polybutene. By using two or more materials with different viscosities together, the adhesiveness, sealability, fluidity, and workability of the sealant material are improved in a well-balanced manner, and the effects are obtained more preferably. This is an organic peroxide cross-linking system using butyl rubber as a rubber component, and a liquid polymer component is introduced to impart tackiness. It is presumed that the performance of the sealant material is improved in a well-balanced manner by suppressing the flow of the. Furthermore, by blending 1 to 30 parts by mass of an inorganic filler with respect to 100 parts by mass of the rubber component, the adhesiveness, sealability, fluidity, and processability of the sealant material are improved in a well-balanced manner, and the effect is more suitable. can get.

In addition, since the sealant material contains an organic peroxide, the sealant material has good adhesiveness even after the sealant material is applied, and the sound absorbing layer can be more preferably attached. After applying the sealant material and before attaching the sound absorbing layer, the cross-linking step described later may or may not be performed, but in any case, the sealant material contains an organic peroxide. By doing so, the sound absorbing layer can be attached more preferably.

The method for producing the pneumatic tire of the present invention is not particularly limited as long as the sound absorbing layer can be provided in the inner cavity of the tire. Preferred examples of the method for producing the sealant tire of the present invention will be described below.

Sealant tires, for example, prepare a sealant material by mixing each component that constitutes the sealant material, and then apply the obtained sealant material to the inner peripheral surface of the tire by coating or the like to form a sealant layer. It can be produced by a known method. The sealant tire has a sealant layer inside the inner liner in the tire radial direction.

The hardness (viscosity) of the sealant material must be controlled according to the rubber component and the amount of cross-linking, and the viscosity must be controlled according to the operating temperature. Therefore, to control the rubber component, the types and amounts of liquid rubber, plasticizer, and carbon black are adjusted. On the other hand, in order to control the amount of cross-linking, the types and amounts of the cross-linking agent and cross-linking aid are adjusted.

The sealant material is not particularly limited as long as it has adhesiveness, and ordinary rubber compositions used for tire puncture sealing can be used. Butyl-based rubber is used as a rubber component that constitutes the main component of the rubber composition. Examples of butyl-based rubber include butyl rubber (IIR) and halogenated butyl rubber (X-IIR) such as brominated butyl rubber (Br-IIR) and chlorinated butyl rubber (Cl-IIR). Among them, from the viewpoint of fluidity, either one or both of butyl rubber and halogenated butyl rubber can be preferably used. In addition, it is preferable to use pelletized butyl rubber. As a result, the butyl-based rubber can be accurately and suitably supplied to the continuous kneader, and the sealant material can be manufactured with high productivity.

As the butyl rubber, from the viewpoint of suppressing a decrease in fluidity of the sealant material, butyl rubber A having a Mooney viscosity ML1+8 at 125°C of 20 or more and less than 40 and/or a butyl rubber having a Mooney viscosity ML1+8 at 125°C of 40 or more and 80 or less Use of rubber B is preferred, and among others, use of at least butyl rubber A is preferred. When butyl-based rubbers A and B are used together, the compounding ratio may be appropriately set.

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

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

The Mooney viscosity ML1+8 at 125°C conforms to JIS K-6300-1: 2001, at a test temperature of 125°C, with an L-shaped rotor preheating for 1 minute and rotating the rotor for 8 minutes. It is what is measured.

Rubber components include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), ethylene propylene diene rubber (EPDM), and chloroprene rubber (CR). , acrylonitrile butadiene rubber (NBR), butyl rubber (IIR) and other diene rubbers may be used in combination. is preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 100% by mass.

Liquid polybutene, liquid polyisobutene, liquid polyisoprene, liquid polybutadiene, liquid poly-α-olefin, liquid isobutylene, liquid ethylene-α-olefin copolymer, liquid ethylene-propylene copolymer, liquid ethylene-butylene copolymer, liquid polybutene, liquid polyisobutene, liquid polyisoprene, liquid polybutadiene, A polymer etc. are mentioned. Among them, liquid polybutene is preferable from the viewpoint of imparting tackiness and the like. Examples of liquid polybutene include copolymers mainly composed of isobutene and having a molecular structure of long-chain hydrocarbon obtained by further reacting normal butene. Hydrogenated liquid polybutene can also be used.

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

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

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

The kinematic viscosity at 40° C. of the liquid polymer A such as liquid polybutene is preferably 20000 mm ² /s or more, more preferably 23000 mm ² /s or more. If it is less than 20000 mm ² /s, the sealant material is soft and may flow. The kinematic viscosity at 40° C. is preferably 30000 mm ² /s or less, more preferably 28000 mm ² /s or less. If it exceeds 30,000 mm ² /s, the viscosity of the sealant material becomes too high, and there is a risk that the sealability will deteriorate.

The kinematic viscosity at 40° C. of the liquid polymer B such as liquid polybutene is preferably 120000 mm ² /s or more, more preferably 150000 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 tire tends to flow during use, possibly deteriorating sealing performance and uniformity.
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 there is a risk that the sealability will deteriorate.

The kinematic viscosity is a value measured under conditions of 100°C and 40°C according to JIS K2283-2000.

The content of the liquid polymer (the total amount of the liquid polymers A, B, etc.) is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, and still more preferably 150 parts by mass or more with respect to 100 parts by mass of the rubber component. be. If the content is less than 50 parts by mass, the adhesiveness may decrease. The content is preferably 400 parts by mass or less, more preferably 300 parts by mass or less, and even more preferably 250 parts by mass or less. If it exceeds 400 parts by mass, the sealant may flow.

When liquid polymers A and B are used in combination, the blending ratio (content of liquid polymer A/content of liquid polymer B) is preferably 10/90 to 90/10, more preferably 30/70 to 70/ 30, more preferably 40/60 to 60/40. Good adhesiveness is provided as it is in the said range.

The organic peroxide (crosslinking agent) is not particularly limited, and conventionally known compounds can be used. By using a butyl rubber or a liquid polymer in an organic peroxide cross-linking system, adhesiveness, sealability, fluidity, and workability are improved.

Examples of organic peroxides include acyl peroxides such as benzoyl peroxide, dibenzoyl peroxide, and p-chlorobenzoyl peroxide, 1-butylperoxyacetate, t-butylperoxybenzoate, t-butylperoxy Peroxyesters such as phthalate, ketone peroxides such as methyl ethyl ketone peroxide, di-t-butyl peroxybenzoate, alkyl peroxides such as 1,3-bis(1-butylperoxyisopropyl)benzene, t- Examples include hydroperoxides such as butyl hydroperoxide, dicumyl peroxide, t-butyl cumyl peroxide and the like. Among them, acyl peroxides are preferred, and dibenzoyl peroxide is particularly preferred, from the viewpoint of adhesiveness and fluidity. Moreover, it is preferable to use a powdery organic peroxide (crosslinking agent). As a result, the organic peroxide (crosslinking agent) can be accurately and suitably supplied to the continuous kneader, and the 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 still more preferably 5 parts by mass or more with respect to 100 parts by mass of the rubber component. If the content is less than 0.5 parts by mass, the crosslink density may be low and the sealant may flow. The content is preferably 40 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less. If it exceeds 40 parts by mass, the cross-linking density becomes high, the sealant material becomes hard, and there is a possibility that the sealability may deteriorate.

Crosslinking aids (vulcanization accelerators) include sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamine, aldehyde-amine, aldehyde-ammonia, imidazoline, xanthate, and quinonedioxime compounds (quinoid compounds) can be used. For example, quinonedioxime compounds (quinoid compounds) can be preferably used. Adhesiveness, sealability, fluidity, and workability are improved by using butyl-based rubber or liquid polymer in a cross-linking system in which a cross-linking aid is further added to an organic peroxide.

The quinonedioxime compounds include p-benzoquinonedioxime, p-quinonedioxime, p-quinonedioxime diacetate, p-quinonedioxime dicaproate, p-quinonedioxime dilaurate, p-quinonedioxime distea rate, p-quinonedioxime dicrotonate, p-quinonedioxime dinaphthenate, p-quinonedioxime succinate, p-quinonedioxime adipate, p-quinonedioxime difuroate, p- quinonedioxime dibenzoate, p-quinonedioxime di(o-chlorobenzoate), p-quinonedioxime di(p-chlorobenzoate), p-quinonedioxime di(p-vitrobenzoate), p-quinonedioxime di(m-vitrobenzoate), p-quinonedioxime di(3,5-dinitrobenzoate), p-quinonedioxime di(p-methoxybenzoate), p-quinonedioxime di(n-amyloxybenzoate), p-quinonedioxime (m-bromobenzoate, etc.). Among them, p-benzoquinonedioxime is preferable from the viewpoint of adhesiveness, sealability, and fluidity. is preferably in the form of powder, so that the cross-linking aid (vulcanization accelerator) can be suitably supplied to the continuous kneader with high accuracy, and the sealant material can be manufactured with high productivity.

The content of the cross-linking aid such as the quinonedioxime compound is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and still more 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 sealant may flow. The content is preferably 40 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less. If the amount exceeds 40 parts by mass, the sealing performance may deteriorate.

Sealants include carbon black, silica, calcium carbonate, calcium silicate, magnesium oxide, aluminum oxide, barium sulfate, talc, inorganic fillers such as mica, aromatic process oil, naphthene process oil, and paraffin process oil. You may add plasticizers, such as.

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 it is less than 1 part by mass, there is a risk that the sealability will deteriorate due to deterioration due to ultraviolet rays. The content is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less. If the amount exceeds 50 parts by mass, the viscosity of the sealant material may become too high and the sealing performance may deteriorate.

Carbon black is preferable as the inorganic filler from the viewpoint of preventing deterioration due to ultraviolet rays. 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 it is less than 1 part by mass, there is a risk that the sealability will deteriorate due to deterioration due to ultraviolet rays. The content is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 25 parts by mass or less. If the amount exceeds 50 parts by mass, the viscosity of the sealant material may become too high and the sealing performance may deteriorate.

The content of the plasticizer is preferably 1 part by mass or more, more preferably 5 parts by mass or more with respect to 100 parts by mass of the rubber component. If the amount is less than 1 part by mass, the adhesiveness to the tire may be lowered and sufficient sealability may not be obtained. The content is preferably 40 parts by mass or less, more preferably 20 parts by mass or less. If it exceeds 40 parts by mass, it may become difficult to knead the sealant due to slippage in the kneader.

The sealant material is preferably prepared by mixing pelletized butyl rubber, powdered cross-linking agent, and powdered cross-linking aid. , a plasticizer, a powdered carbon black, a powdered cross-linking agent, and a powdered cross-linking aid. Thereby, each raw material can be suitably supplied to a continuous kneader, and a sealant material can be manufactured with high productivity.

As the sealant material, it is preferable to mix predetermined amounts of a liquid polymer, an organic peroxide, and a cross-linking aid with a rubber component containing butyl rubber.

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

The viscosity (90° C.) of the sealant material is not particularly limited. From the viewpoint, it is preferably 0.5 kPa·s or more, more preferably 1.0 kPa·s or more, still more preferably 3.0 kPa·s or more, and preferably 30.0 kPa·s or less, more preferably 20.0 kPa·s or more. It is 0 kPa·s or less, more preferably 7.0 kPa·s or less. If it is less than 0.5 kPa·s, the sealant may flow when the tire is stopped after application of the sealant, and the film thickness may not be maintained. Moreover, when it exceeds 30.0 kPa·s, it becomes difficult to discharge the sealant material from the nozzle.
In addition, in this specification, the viscosity of the sealant material is a value measured by a rotary viscometer at 90° C. in accordance with JIS K 6833.

By mixing each of the above materials to prepare a sealant material and applying the produced sealant material to the inner peripheral surface of the tire (preferably the inner liner in the tire radial direction), A sealant tire having a sealant layer can be manufactured, and each material constituting the sealant can be mixed using, for example, a known continuous kneader. Among them, it is preferable to use a co-rotating or counter-rotating multi-screw kneading extruder, particularly a twin-screw kneading extruder.

A continuous kneader (especially a twin-screw kneading extruder) preferably has a plurality of supply ports for supplying raw materials, and more preferably has at least three supply ports. It is even more preferred to have one supply port. By sequentially supplying the above various raw materials to a continuous kneader (particularly, a twin-screw kneading extruder), the above various raw materials are mixed and the sealant material is sequentially and continuously prepared.

It is preferable to supply raw materials to a continuous kneader (particularly, a twin-screw kneading extruder) in order of increasing viscosity. As a result, each material is thoroughly mixed, and a sealant material of uniform quality can be prepared. In addition, since the kneading property is improved when the powder material is added, it is desirable to add it as upstream as possible.

It is preferable to supply the organic peroxide to the continuous kneader (especially the twin-screw kneading extruder) from the downstream supply port. As a result, the time from the supply of the organic peroxide to the application of the sealant material to the tire can be shortened, so that the sealant material can be applied to the tire before curing progresses, and the sealant tire can be manufactured more stably.

If a large amount of liquid polymer is fed into a continuous kneader (especially a twin-screw kneading extruder) at one time, kneading will not go well. Oral is preferred. Thereby, kneading of the sealant material can be performed more suitably.

When using a continuous kneader (especially a twin-screw kneading extruder), the sealant material uses a continuous kneader (especially a twin-screw 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 cross-linking aid are supplied from the upstream supply port of the shaft kneading extruder), the liquid polymer B is supplied from the midstream supply port, and the downstream It is preferably prepared by supplying liquid polymer A, an organic peroxide and a plasticizer from a supply port, and kneading and extruding. Although all or part of each material such as liquid polymer may be supplied from each supply port, it is preferable to supply 95% by mass or more of the total amount of each material.

It is preferable that all raw materials to be fed into the continuous kneader are controlled by a feeding device capable of controlling constant supply and fed into the continuous kneader. This makes it possible to prepare the sealant material in a continuous and automated manner.

The feeding device is not particularly limited as long as it is capable of controlling constant feeding, and known feeding devices can be used, for example, screw feeders, plunger pumps, gear pumps, mono pumps and the like can be used.

Solid raw materials (especially pellets and powders) such as pelletized butyl rubber, powdered carbon black, powdered cross-linking agent, and powdered cross-linking aid are quantitatively fed using a screw feeder. is preferred. As a result, it is possible to accurately supply the solid raw material in a fixed quantity, and to manufacture a sealant material of higher quality and, in turn, a sealant tire of higher quality.

Moreover, it is preferable to supply each solid raw material with a separate supply apparatus, respectively. This eliminates the need to blend each raw material in advance, facilitating the supply of materials during mass production.

The plasticizer is preferably metered using a plunger pump. As a result, the plasticizer can be accurately and quantitatively supplied, and a higher quality sealant material and thus a higher quality sealant tire can be manufactured.

The liquid polymer is preferably metered 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 liquid polymer to be supplied is preferably controlled at a constant temperature. Controlling the constant temperature makes it possible to supply the liquid polymer in a fixed amount with higher accuracy. The temperature of the supplied liquid polymer is preferably 20-90°C, more preferably 40-70°C.

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

From the viewpoint of sufficient mixability, it is preferable that the mixing time for the materials supplied upstream is 1 to 3 minutes, and the mixing time for the materials supplied midstream is 1 to 3 minutes. On the other hand, from the viewpoint of preventing cross-linking, the mixing time of the materials supplied downstream is preferably 0.5 to 2 minutes. In addition, each mixing time refers to the residence time from feeding to a continuous kneader (especially a twin-screw kneading extruder) until it is discharged. For example, the mixing time of materials supplied downstream is is the residence time from the time of supply to the supply port of the gas until it is discharged.

The screw speed of the continuous kneader (especially the twin-screw kneading extruder) and the setting of the temperature controller can be used to adjust the temperature of the sealant material discharged from the discharge port, thereby controlling the curing acceleration speed of the sealant material. . In a continuous kneader (particularly, a twin-screw kneading extruder), the kneadability and material temperature increase as the number of rotations of the screws is increased. Note that the number of rotations of the screw does not affect the discharge amount. The rotation speed of the screw is preferably 50 to 700 (preferably 550) rpm from the viewpoint of sufficient mixability and control of curing acceleration speed.

The temperature of the sealant material discharged from the discharge port of a continuous kneader (especially a twin-screw kneading extruder) is preferably 70 to 150 ° C. from the viewpoint of sufficient mixability and control of the curing acceleration speed. It is more preferably 90 to 130°C. When the temperature of the sealant material is within the above range, the cross-linking reaction starts from the time of application, has good adhesion to the inner peripheral surface of the tire, and the cross-linking reaction proceeds more favorably, resulting in a sealant tire with high sealability. can be manufactured. Moreover, the cross-linking step, which will be described later, is not required.

The amount of sealant material discharged from the outlet of a continuous kneader (particularly, a twin-screw kneading extruder) is determined based on the amount of raw material supplied to the supply port. The amount of raw material supplied 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 for the reason that a sealant tire having excellent uniformity and sealing properties can be suitably obtained.
Here, in this specification, the discharge amount is substantially constant means that the discharge amount fluctuates by 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 outlet of the continuous kneader (especially a twin-screw kneading extruder). A continuous kneader (particularly, a twin-screw kneading extruder) can discharge the material at high pressure. bead) and can be attached to the tire. That is, 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, the thickness of the sealant material is substantially This makes it possible to prevent deterioration of the uniformity of the tire and to manufacture a sealant tire having an excellent weight balance.

Next, the mixed sealant material is discharged from a nozzle connected to the discharge port of an extruder such as a continuous kneader (especially a twin-screw kneading extruder), and directly fed to the inner peripheral surface of the vulcanized tire. , to the inner peripheral surface, etc., to produce a sealant tire. As a result, the sealant material mixed in a twin-screw kneading extruder or the like and the progress of the cross-linking reaction in the extruder is suppressed can be applied to the inner peripheral surface of the tire as it is. It has good adhesiveness to the peripheral surface, and the cross-linking reaction proceeds favorably. As a result, the sealant material applied to the inner peripheral surface of the tire preferably forms a sealant layer while maintaining a substantially string-like shape. Therefore, the sealant can be applied in a series of steps, and the productivity is further improved. Further, by applying the sealant material to the inner peripheral surface of the vulcanized tire, the sealant tire can be manufactured with higher productivity. Furthermore, it is preferable to sequentially apply the sealant material discharged from a nozzle connected to the discharge port of a continuous kneader (especially a twin-screw kneading extruder) directly onto the inner peripheral surface of the tire. As a result, the sealant material in which the progress of the cross-linking reaction in the continuous kneader (especially the twin-screw kneading extruder) is suppressed can be continuously applied to the inner peripheral surface of the tire as it is, so the cross-linking reaction starts from the time of application. It has good adhesiveness to the inner peripheral surface of the tire, and the cross-linking reaction proceeds favorably, so that it is possible to manufacture a sealant tire with high productivity and excellent weight balance.

Application of the sealant material to the inner peripheral surface of the tire may be performed at least on the inner peripheral surface of the tire corresponding to the tread portion, more preferably at least on the inner peripheral surface of the tire corresponding to the breaker. By omitting the application of the sealant material to portions that do not need to be applied, sealant tires 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 radially inside 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 inside the breaker in the tire radial direction. The breaker is a member arranged inside the tread and radially outward of the carcass, and specifically, it is a member such as the breaker 16 in FIG.

Unvulcanized tires are usually vulcanized using a bladder. This bladder expands during vulcanization and comes into close contact with the inner peripheral surface (inner liner) of the tire. Therefore, 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 to each other when vulcanization is completed.

Water-soluble paints and release rubbers are usually used as release agents. However, if the 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 decrease. Therefore, it is preferable to remove the release agent from the inner peripheral surface of the tire in advance. In particular, it is more preferable to remove the release agent in advance at least from the portion of the inner peripheral surface of the tire where the application of the sealant material is to be started. In addition, it is more preferable to previously remove the release agent from all portions of the inner peripheral surface of the tire to which the sealant material is to be applied. As a result, the adhesion of the sealant material to the inner peripheral surface of the tire is further improved, and a sealant tire with higher sealability can be manufactured.

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

Here, an example of manufacturing equipment used in the method of manufacturing a sealant tire will be briefly described with reference to FIG.
The manufacturing equipment includes a twin-screw kneading extruder 60, a material feeder 62 that supplies raw materials to the twin-screw kneading extruder 60, and a rotation drive device 50 that rotates the tire 10 while fixing it and moves it in the width direction and radial direction of the tire. have The twin-screw 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, a nozzle 30 is connected to the outlet of the twin-screw kneading extruder 60 .

Raw materials are sequentially supplied from a material feeder 62 to a twin-screw kneading extruder 60 through a supply port 61 of the twin-screw kneading extruder 60, and each raw material is kneaded by the twin-screw kneading extruder 60 to sequentially prepare a sealant material. be done. The prepared sealant material is continuously discharged from the nozzle 30 connected to the discharge port of the twin-screw kneading extruder 60 . The tire is traversed and/or lifted (moved in the width direction and/or radial direction of the tire) while being rotated by the tire driving device, and the sealant material discharged from the nozzle 30 is sequentially applied directly to the inner peripheral surface of the tire. Thus, the sealant material can be continuously and helically applied to the inner peripheral surface of the tire. That is, while rotating the tire and moving it in the width direction and / or radial direction of the tire, the sealant material continuously discharged from the continuous kneader (especially the twin-screw kneading extruder) is sequentially applied to the inner peripheral surface of the tire. By applying the sealant directly, it is possible to apply the sealant continuously and spirally to the inner peripheral surface of the tire.

By continuously and spirally applying the sealant material to the inner peripheral surface of the tire, it is possible to prevent deterioration of the uniformity of the tire and to manufacture a sealant tire excellent in weight balance. In addition, by continuously applying the sealant material to the inner peripheral surface of the tire in a spiral shape, the sealant material can form a uniform sealant layer in the tire circumferential direction and the tire width direction (especially in the tire circumferential direction), so that the sealant can be It is possible to stably manufacture sealant tires with excellent durability with high productivity. The sealant material is preferably attached so as not to overlap in the width direction, and more preferably attached without gaps. As a result, it is possible to further prevent deterioration of tire uniformity and form a more uniform sealant layer.

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

The sealant layer is preferably formed by continuously spirally applying a substantially string-shaped sealant material to the inner peripheral surface of the tire. As a result, it is possible to form on the inner peripheral surface of the tire a sealant layer composed of a substantially string-shaped sealant material that is continuously spirally arranged along the inner peripheral surface of the tire. The sealant layer may be formed by laminating sealant materials, but preferably consists of one layer of sealant material.

When the sealant material has a substantially string-like shape, a sealant layer consisting of one layer of the sealant material can be formed by applying the sealant material continuously and spirally to the inner peripheral surface of the tire. When the sealant material has a substantially string-like shape, the applied sealant material has a certain thickness. A sealant tire having excellent balance and good sealing performance can be produced. Moreover, since it is sufficient to apply only one layer of the sealant material without laminating many layers, the sealant tire can be manufactured with higher productivity.

The number of times the sealant material is wound around the inner peripheral surface of the tire is preferable because it is possible to prevent the deterioration of the uniformity of the tire, to achieve excellent weight balance, and to manufacture a sealant tire having good sealing performance with high productivity. 20 to 70 times, more preferably 20 to 60 times, still more preferably 35 to 50 times. Here, the number of times of winding is two times means that the sealant material is applied so as to make two turns around the inner peripheral surface of the tire. In FIG. 4, the number of times of winding the sealant material is six times.

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 continuously at the same time. The sealant material, which is difficult to handle, can be applied directly to the inner peripheral surface of the tire without handling, and sealant tires can be manufactured with high productivity. In addition, when the sealant material is prepared by kneading the curing agent in a batch-type kneading device, the time from the preparation of the sealant material to the application to the tire is not constant, but the raw material containing the organic peroxide is continuously kneaded. By 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, the time from preparation of the sealant material to application to the tire becomes constant. Therefore, when applying the sealant material using a nozzle, the amount of sealant material discharged from the nozzle is stable, and furthermore, the adhesiveness of the sealant material to the tire is kept constant while suppressing the decrease in adhesiveness. Even if a sealant material that is highly viscous, highly adhesive, and difficult to handle is used, it can be applied to the inner peripheral surface of the tire with high precision, and a sealant tire with a constant quality can be stably manufactured.

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

<First embodiment>
In the first embodiment, the tire is rotated and at least one of the tire and the nozzle is moved in the width direction of the tire, and the adhesive sealant material is applied to the inner peripheral surface of the tire by the nozzle. When applying, a step (1) of measuring the distance between the inner peripheral surface of the tire and the tip of the nozzle with a non-contact displacement sensor, and moving at least one of the tire and the nozzle in the radial direction of the tire based on the measurement result. A step (2) of adjusting the gap between the inner peripheral surface of the tire and the tip of the nozzle to a predetermined distance by moving the nozzle to the inner peripheral surface of the tire with the adjusted gap, and applying the sealant material to the inner peripheral surface of the tire It can be produced by carrying out the step (3).

By measuring the distance between the inner surface of the tire and the tip of the nozzle using a non-contact displacement sensor and feeding back the measurement results, the distance between the inner surface of the tire and the tip of the nozzle can be kept constant. can keep. Since the sealant is applied to the inner peripheral surface of the tire while maintaining a constant distance, the thickness of the sealant is uniform without being affected by variations in tire shape or irregularities in joints. can be Furthermore, since there is no need to input coordinate values for each tire size as in the conventional system, the sealant material can be applied efficiently.

FIG. 1 is an explanatory view schematically showing an example of an applicator used in a method for manufacturing a sealant tire. Moreover, FIG. 2 is an enlarged view of the vicinity of the tip of a nozzle that constitutes the coating apparatus shown in FIG.

FIG. 1 shows a cross section of a portion of the tire 10 taken in the meridian direction (a cross section taken along a plane including the width direction and radial direction of the tire), and FIG. It shows a cross-section through a plane containing the direction and the radial direction. 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 in a rotation drive device (not shown) that fixes and rotates the tire and moves it in the width direction and radial direction of the tire. This rotary drive device independently enables rotation of the tire about its axis, movement of the tire in the width direction, and movement of the tire in the radial direction.

The rotary drive device also has a control mechanism (not shown) capable of controlling the amount of radial movement of the tire. The control mechanism may be capable of controlling the amount of lateral movement 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 the radial distance of the tire between the inner peripheral surface of the tire and the tip of the nozzle.

In the method of manufacturing a sealant tire according to the present embodiment, first, the tire 10 molded in the vulcanization process is set in the rotary drive device, and the nozzle 30 is inserted inside the tire 10 . Then, as shown in FIGS. 1 and 2 , the tire 10 is rotated and the sealant material 20 is discharged from the nozzle 30 while the tire 10 is being moved in the width direction so that the sealant material 20 is continuously applied to the inner peripheral surface 11 of the tire 10 . apply evenly. The movement of the tire 10 in the width direction is performed along the previously input profile shape of the inner peripheral surface 11 of the tire 10 .

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

In this specification, the term "substantially string-like shape" means a shape whose length is longer than its width and which has a certain amount of width and thickness. FIG. 4 schematically shows an example of a state in which a substantially string-shaped sealant material is continuously and spirally attached to the inner peripheral surface of a tire. Further, 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 perpendicular to the application direction (longitudinal direction) of the sealant material. Thus, the substantially string-shaped sealant material has a certain width (length indicated by W in FIG. 8) and a certain thickness (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 is the thickness of the sealant material after application, more specifically, the thickness of the sealant layer. means

Specifically, the substantially string-shaped sealant material has a thickness of the sealant material (the thickness of the sealant material after application, the thickness of the sealant layer, and the length indicated by D in FIG. 8), which will be described later. A sealant material that satisfies a preferable numerical range and a preferable numerical range of the width of the sealant material (the width of the sealant material after application, the length indicated by W in FIG. 4, and the length indicated by _W0 in FIG. 6), More preferably, the sealant material satisfies the preferred numerical range of the ratio of the thickness of the sealant material to the width of the sealant material (thickness of the sealant material/width of the sealant material), which will be described later. It is also a sealant material that satisfies the preferable numerical range of the cross-sectional area of the sealant material, which will be described later.

In the method for manufacturing a sealant tire according to 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, the non-contact displacement sensor 40 measures the 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 distance d is measured each time the sealant material 20 is applied to the inner peripheral surface 11 of each tire 10, from the start of application of the sealant material 20 to the end of application.

<Step (2)>
The measurement data of the distance d are transferred to the control mechanism of the rotary drive. Based on the measurement data, the control mechanism adjusts the amount of radial movement 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 where the interval is adjusted. Through the steps (1) to (3) described above, 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 nozzles with respect to the tire.
As shown in FIG. 3, while the nozzle 30 moves to the positions 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. The sealant material can be applied while maintaining _d0 .

The distance d0 after adjustment is preferably 0.3 mm or more, and more preferably _1.0 mm or more, because the effect can be obtained more preferably. If it is less than 0.3 mm, the tip of the nozzle is too close to the inner peripheral surface of the tire, making it difficult to apply a sealant material having a predetermined thickness. Further, the distance d0 after adjustment is preferably _3.0 mm or less, more preferably 2.0 mm or less. If it exceeds 3.0 mm, the sealant material may not adhere well to the tire, resulting in a decrease in manufacturing efficiency.
Here, the distance d0 after adjustment is the distance in the radial direction of the tire between the inner peripheral surface of the tire and the tip of the nozzle after adjustment in step ( ₂ ).

In addition, since the effect can be obtained more preferably, the distance d ₀ after adjustment is preferably 30% or less, more preferably 20% or less, of the thickness of the sealant material after application. is preferably 5% or more, more preferably 10% or more, of the thickness of the

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 it is preferable because the effect can be obtained more preferably. is 1.0 mm or more, more preferably 1.5 mm or more, still more preferably 2.0 mm or more, particularly preferably 2.5 mm or more, and preferably 10.0 mm or less, more preferably 8.0 mm or less, and further Preferably, it is 5.0 mm or less. If it is less than 1.0 mm, it will be difficult to reliably close the puncture hole when the tire is punctured. Moreover, even if it exceeds 10.0 mm, the effect of plugging a puncture hole does not change 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 of the tire in the width direction, the distance between the tip of the nozzle and the inner peripheral surface of the tire, and the like.

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

It is preferable to use a substantially string-shaped sealant material for the reason that the nozzle is less clogged and has excellent operational stability, and for the reason that the effect is more preferably obtained. It is more preferable to attach it spirally to the inner peripheral surface of the tire. However, a sealant material that does not have a substantially string-like shape may be used and the sealant material may be applied by spraying it on the inner peripheral surface of the tire.

When using a substantially string-shaped sealant material, 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 it is said that the effect can be obtained more preferably. For these reasons, it is preferably 0.8 mm or more, more preferably 1.3 mm or more, and even more 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, which may reduce manufacturing efficiency. 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 below. If it exceeds 18 mm, weight imbalance may easily occur.

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 of the sealant material (the width of the sealant material after application, in FIG. 4 , W) ratio (thickness of sealant material/width of sealant material) is preferably 0.6 to 1.4, more preferably 0.7 to 1.3, and still more preferably 0.7 to 1.3. 8 to 1.2, particularly preferably 0.9 to 1.1. The closer the ratio is to 1.0, the more ideal the shape of the sealant material is, the string-like shape, and the more productively the sealant tire with high sealability can be manufactured.

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, more It is 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, still more preferably 45 mm ² or less, and particularly preferably is 35 mm ² or less, most preferably 25 mm ² or less.

The width of the area where the sealant material is attached (hereinafter also referred to as the width of the attached area or the width of the sealant layer, the length represented by 6 × W in FIG. 4, and W ₁ + 6 × W ₀ in FIG. 6) Although the expressed length) is not particularly limited, it is preferably 80% or more, more preferably 90% or more, even more preferably 100% or more of the tread ground contact width because the effect is more preferably obtained. % or less is preferable, and 110% or less is more preferable.

The width of the sealant layer is preferably 85 to 115% of the tire breaker width (the length of the breaker in the tire width direction), and more preferably 95 to 105%, because the effect is more preferably obtained. more preferred.
In this specification, when a tire is provided with a plurality of breakers, the length of the breaker in the tire width direction is the length of the breaker having the longest length in the tire width direction among the plurality of breakers. means length.

In this specification, the tread contact width is defined as follows. First, the outermost ground contact position in the axial direction of the tire, which is mounted on a regular rim and inflated to a regular internal pressure, is in a regular state without load, and is grounded on a flat surface with a camber angle of 0 degrees under a regular load. is defined as the "earth end" Te. A tread contact width TW is defined as a distance in the tire axial direction between the contact points Te and Te. Unless otherwise specified, the dimensions of each part of the tire are the values measured in this normal state.

The above-mentioned "regular rim" is a rim defined for each tire by each standard in the standard system including the standard on which the tire is based. , ETRTO, it becomes "Measuring Rim". In addition, the above-mentioned "regular internal pressure" is the air pressure determined for each tire by each standard in the standard system including the standard on which the tire is based. Maximum value described in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", "INFLATION PRESSURE" for ETRTO, but 180 kPa for tires for passenger cars.

In addition, the above-mentioned "regular load" is the load specified for each tire by each standard in the standard system including the standard on which the tire is based. The maximum value described in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", which is "LOAD CAPACITY" for ETRTO, is equivalent to 88% of the above load when the tire is for a passenger car.

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/min because the effect is more preferably 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 with a uniform thickness.

By using a non-contact displacement sensor, it is possible to reduce the risk of failure due to the sealant material adhering to the sensor. The non-contact 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. Examples include laser sensors, optical sensors, and capacitance sensors. . These sensors may be used alone or in combination of two or more. Among them, 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, the inner peripheral surface of the tire is irradiated with a laser, the distance between the inner peripheral surface of the tire and the tip of the laser sensor is measured from the reflection of the laser. By subtracting the distance from , 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 displacement sensor 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 before applying the sealant material, but it is preferable to attach it to the nozzle, and the sealant material It is more preferable to install it in a position where it does not adhere.

In addition, the number, size, etc. of the non-contact displacement sensors are not particularly limited.

Since non-contact displacement sensors are vulnerable to heat, they should be protected with heat insulating material and/or cooled with air, etc., in order to prevent the heat from the high-temperature sealant discharged from the nozzle. is preferred. Thereby, the durability of the sensor can be improved.

In the description of the first embodiment, an example was described in which the tire moves without moving the nozzle as the movement in the width direction and radial direction of the tire. Both nozzles may move.

Preferably, the rotary drive device also has means for widening the bead portion of the 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 into the vicinity of the inner peripheral surface of the tire after the tire is set on the rotary drive device, the nozzle can be introduced simply by moving the nozzle in parallel, thereby facilitating control and improving productivity.

The means for widening the bead portion of the tire is not particularly limited as long as it is possible to widen the width of the bead portion of the tire. , each of which moves in the tire width direction. The device can be inserted into the tire from both sides of the tire opening to widen the bead portion of the tire.

In the above production method, the sealant material mixed in a twin-screw kneading extruder or the like and the progress of the cross-linking reaction in the extruder is suppressed is applied to the inner peripheral surface of the tire as it is. It has good adhesiveness to the inner peripheral surface of the tire, and the cross-linking reaction proceeds more favorably, so that a sealant tire with high sealability can be produced. Therefore, it is not necessary to further crosslink the sealant tire to which the sealant material is applied, and good productivity can be obtained.

If necessary, a cross-linking step of further cross-linking the sealant tire to which the sealant material has been applied may be performed.
Preferably, the sealant tire is heated in the cross-linking step. As a result, the speed of crosslinking of the sealant material can be improved, the crosslinking reaction can proceed more favorably, and sealant tires can be produced with higher productivity. A heating method is not particularly limited, and a known method can be employed, but a method using an oven is preferable. For the cross-linking 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 when crosslinking because it is possible to perform the crosslinking reaction without deteriorating the uniformity by preventing the fluidity even if the sealant material is easy to flow immediately after application. The rotation speed is preferably 300-1000 rpm. Specifically, for example, an oven with a rotating mechanism may be used as the oven.

Further, even if the cross-linking step is not separately performed, it is preferable to rotate the tire in the tire circumferential direction until the cross-linking reaction of the sealant material is completed. As a result, the cross-linking reaction can be performed without deteriorating the uniformity of the sealant material, which is easily flowable immediately after application, by preventing the flow. The rotation speed is the same as for the cross-linking step.

In order to improve the speed of cross-linking of the sealant material, it is preferable to preheat the tire before applying the sealant material. Thereby, a sealant tire can be manufactured with higher productivity. The tire preheating temperature 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 cross-linking reaction starts favorably from the time of coating, the cross-linking reaction proceeds more favorably, and a sealant tire with high sealability can be produced. Further, by setting the preheating temperature of the tire within the above range, it is possible to manufacture the sealant tire with high productivity because the cross-linking step is not required.

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 after the application to one tire is completed. In this case, the following methods (1) and (2) may be adopted in order to manufacture sealant tires of higher quality while suppressing a decrease in productivity. The method (1) has the demerit of lowering the quality, and the method (2) has the demerit of increased cost.
(1) The continuous kneader and all supply devices are operated and stopped at the same time to control the supply of the sealant material to the inner peripheral surface of the tire. All 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 at the same time, and application to the tire is restarted. By replacing the tire quickly (preferably within 1 minute), deterioration in quality can be suppressed.
(2) Control the supply of the sealant material to the inner peripheral surface of the tire by switching the flow path while the continuous kneader and all the supply devices are in operation. A passage separate from the nozzle that feeds directly into the sealant is provided, and when application to one tire is completed, the prepared sealant material can be discharged from another passage until tire replacement is completed. According to this method, a sealant tire can be manufactured while the continuous kneader and all supply devices are in operation, so that a higher quality sealant tire can be manufactured.

Carcass cords used for the carcass of the sealant tire are not particularly limited, and examples thereof include fiber cords and steel cords. Among them, steel cords are preferred. Among others, steel cords made of hard steel wire specified in JIS G3506 are desirable. In sealant tires, by using high-strength steel cords as carcass cords instead of the fiber cords that are commonly used, side cut resistance is significantly improved resistance) can be improved, and the puncture resistance of the entire tire including the side portion can be further improved.

The structure of the steel cord is not particularly limited, and examples thereof include a 1×n single-stranded steel cord, a k+m layer-twisted steel cord, a 1×n bundle-twisted steel cord, and an m×n double-stranded steel cord. I can give you the code. Here, the single-twisted steel cord having a 1×n configuration is a single-layer stranded steel cord obtained by twisting n filaments together. A k+m layer-twisted steel cord is a steel cord having a two-layer structure with different twisting directions and twisting pitches, and having k filaments in the inner layer and m filaments in the outer layer. A stranded steel cord having a 1×n configuration is a stranded steel cord obtained by bundling and twisting n filaments. 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 together. n is an integer of 1-27, k is an integer of 1-10, and m is an integer of 1-3.

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

The steel cord preferably includes at least one helically shaped shaped filament. Such typed filaments can improve rubber permeability by providing a relatively large gap in the steel cord, maintain elongation under low load, and prevent the 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 initial adhesion to the rubber composition.

The steel cord preferably has an elongation of 0.5 to 1.5% under a load of 50N. If the elongation under a load of 50 N exceeds 1.5%, the elongation of the reinforcing cords becomes small under a high load, which may make it impossible to maintain the disturbance absorbability. Conversely, if the elongation under a load of 50 N is less than 0.5%, the elongation cannot be sufficiently achieved during vulcanization molding, and molding defects may occur. From this point of view, the elongation under a load of 50 N is more preferably 0.7% or more and more preferably 1.3% or less.

The steel cord ends are preferably 20 to 50 (cords/5 cm).

<Second embodiment>
With only the method of the first embodiment, when the sealant material has a substantially string-like shape, it may be difficult to apply the sealant material to the inner peripheral surface of the tire. As a result of investigations by the present inventors, it has become clear that there is a problem that it is easy to use. In the second embodiment, in the method for manufacturing a sealant tire, the distance between the inner peripheral surface of the tire and the tip of the nozzle is set to a distance d1, and after the sealant material is applied, the distance is set to _a distance d larger _than the distance d1. ₂ , and a sealant material is applied. As a result, the distance between the inner peripheral surface of the tire and the tip of the nozzle at the start of application can be shortened, so that the width of the sealant material corresponding to the application start portion can be widened, and at least the tire corresponding to the tread portion can be provided. A substantially string-shaped sealant material having adhesiveness is continuously and spirally attached to the inner peripheral surface of the sealant material, and at least one of the ends in the length direction of the sealant material extends in the length direction It is possible to easily manufacture a sealant tire characterized by a wide portion that is wider than the portion adjacent to the . In the sealant tire, by widening the width of the sealant material corresponding to the attachment start portion, the adhesive strength of the portion can be improved and the peeling of the sealant material at the portion can be prevented.
In addition, in the description of the second embodiment, mainly only points different from the first embodiment will be described, and descriptions of the contents overlapping with the first embodiment will be omitted.

FIG. 5 is an enlarged view of the vicinity of the tip of the nozzle constituting the applicator shown in FIG. there is

FIG. 5 shows a cross section of a portion of the tire 10 taken along a plane including the circumferential direction and 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 the rotary drive device, and the nozzle 30 is inserted inside the tire 10 . Then, 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 so that the sealant material 20 is continuously applied to the inner peripheral surface 11 of the tire 10 . apply evenly. The movement of the tire 10 in the width direction is performed, for example, along the previously input profile shape of the inner peripheral surface 11 of the tire 10 .

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

At this time, as shown in FIG. 5( _a ), the sealant material 20 is applied with the distance d1 between the inner peripheral surface 11 of the tire 10 and the tip 31 of the nozzle 30 for a predetermined time after the start of application. wear. After a predetermined period of time has passed, the tire 10 is moved in the radial direction to change the distance to _a distance d2 larger _than the distance d1, and the sealant material 20 is adhered, as shown in FIG. 5(b).

_The distance may be returned from the distance d2 to the distance d1 before _finishing the application of the sealant material. is preferably a distance _d2 .

Further, it is preferable to keep the value of the distance d1 constant for _a predetermined time from the start of attachment, and keep the value of the distance d2 constant after the predetermined _time has elapsed, but the relationship _d1 < _d2 is maintained. The values of distances d ₁ and d ₂ do not necessarily have to be constant as long as the conditions are satisfied.

Although the value of the distance d1 is not particularly limited, it is preferably 0.3 _mm or more, more preferably 0.5 mm or more, because the effect can be obtained more preferably. If it is less than 0.3 mm, the tip of the nozzle is too close to the inner peripheral surface of the tire, and the sealant material tends to adhere to the nozzle, which may increase the frequency of cleaning the nozzle. Also, the value of the distance d1 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.

_The value of the distance d2 is also not particularly limited, but is preferably 0.3 mm or more, more preferably 1 mm or more, and is preferably 3 mm or less, more preferably 2 mm or less, because the effect can be obtained more preferably. is. _The distance _d2 is preferably the same as the adjusted spacing d0 described above.

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

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/min because the effect is more preferably obtained. /min or less, more preferably 20 m/min or less. If it is less than 5 m/min or more than 30 m/min, it will be difficult to affix the sealant material with a uniform thickness.

Through the steps described above, the sealant tire of the second embodiment can be manufactured.
FIG. 6 is an explanatory diagram schematically showing an example of the sealant material attached to the sealant tire of the second embodiment.

The substantially string-shaped sealant material 20 is wound in the circumferential direction of the tire and is continuously attached in a spiral shape. One end of the sealant material 20 in the length direction forms a wide portion 21 that is wider than the portion adjacent to it in the length direction. This wide portion 21 corresponds to a portion where the sealant starts to be applied.

The width of the wide portion of the sealant material (the width of the wide portion of the sealant material after application, the length indicated by W1 in FIG. ₆ ) is not particularly limited. It is preferably 103% or more, more preferably 110% or more, and still more preferably 120% or more of the width other than the width (the length indicated by _W0 in FIG. 6). If it is less than 103%, the effect of providing the wide portion may not be sufficiently obtained. The width of the wide portion of the sealant material is preferably 210% or less, more preferably 180% or less, and even more preferably 160% or less of the width of the portion other than the wide portion. If it exceeds 210%, it is necessary to bring the tip of the nozzle too close to the inner peripheral surface of the tire to form the wide portion, so the sealant material tends to adhere to the nozzle, which may increase the frequency of cleaning the nozzle. There is Moreover, there is a possibility that the weight balance of the tire may be lost.

The width of the wide portion of the sealant material is preferably substantially constant in the length direction, but there may be portions where the width is not substantially constant. For example, the wide portion may have the widest width at the attachment start portion, and the width may become narrower along the length direction. Here, in this specification, the width is substantially constant means that the width variation is 90 to 110% (preferably 97 to 103%, more preferably 98 to 102%, further preferably 99 to 101%). means to fit.

The length of the wide portion of the sealant material (the length of the wide portion of the sealant material after application, the length indicated by L1 in FIG. ₆ ) is not particularly limited. It is preferably less than 650 mm, more preferably less than 500 mm, still more preferably less than 350 mm, particularly preferably less than 200 mm. If the distance 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 longer, so that the sealant material tends to adhere to the nozzle, which may increase the frequency of cleaning the nozzle. Moreover, there is a possibility that the weight balance of the tire may be lost. The length of the wide portion of the sealant material is preferably as short as possible, but considering the control of the distance between the inner peripheral surface of the tire and the tip of the nozzle, the limit is about 10 mm.

The width of the sealant material other than the wide portion (the width of the sealant material other than the wide portion after application, the length indicated by _W0 in FIG. 6) is not particularly limited. It is preferably 0.8 mm or more, more preferably 1.3 mm or more, and still more 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, which may reduce manufacturing efficiency. In addition, 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 6.0 mm or less. is 5.0 mm or less. If it exceeds 18 mm, weight imbalance may easily occur. W ₀ is preferably the same as W described above.

It should be noted that the width of the sealant material other than the wide portion is preferably substantially constant in the longitudinal direction, but there may be portions that are not substantially constant.

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

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

In the sealant tire of the second embodiment, the sealant material is preferably applied so as not to overlap in the width direction, and more preferably adhered without gaps.

In addition, in the sealant tire of the second embodiment, the other end in the length direction of the sealant material (the end corresponding to the end portion of the pasting) is also a wide portion wider than the adjacent portion 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 it is preferable because the effect can be obtained more preferably. is 1.0 mm or more, more preferably 1.5 mm or more, still more preferably 2.0 mm or more, particularly preferably 2.5 mm or more, and preferably 10 mm or less, more preferably 8.0 mm or less, still more preferably 5.0 mm or less. If it is less than 1.0 mm, it will be difficult to reliably close the puncture hole when the tire is punctured. Moreover, even if it exceeds 10 mm, the effect of plugging a puncture hole does not change much, and the weight of the tire increases, which is not preferable.

The thickness of the sealant material (the thickness of the sealant material after application, the thickness of the sealant layer) is preferably substantially constant. As a result, deterioration of tire uniformity can be further prevented, and a sealant tire having a more excellent 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 part of the sealant material (the wide width of the sealant material after application The ratio (thickness of the sealant material/width of the sealant material other than the wide portion) of the width other than the portion (the length indicated by W ₀ in FIG. 6) is preferably 0.6 to 1.4, more preferably 0.7 to 1.3, more preferably 0.8 to 1.2, particularly preferably 0.9 to 1.1. The closer the ratio is to 1.0, the more ideal the shape of the sealant material is, the string-like shape, and the more productively the sealant tire with high sealability can be manufactured.

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, more It is 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, still more preferably 45 mm ² or less, and particularly preferably is 35 mm ² or less, most preferably 25 mm ² or less.

In the second embodiment, even if the viscosity of the sealant material is within the above range, particularly even if the viscosity is relatively high, by widening the width of the sealant material corresponding to the attachment start portion, adhesion of the portion can be improved. The force can be improved and delamination of the sealant material in the area can be prevented.

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

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. Instead, 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 coordinate values input in advance.

A sealant tire having a sealant layer inside the inner liner in the radial direction of the tire can be manufactured by the manufacturing method described above. Among other things, problems such as the flow of the sealant material are unlikely to occur, and there are advantages such as being able to respond by programming even if the tire size changes. It is preferably formed by a manufacturing method that In addition, because the sealant material is easy to handle and highly productive, it is formed by a manufacturing method in which the sealant material, which is sequentially prepared by mixing raw materials containing a cross-linking agent with a continuous kneader, is sequentially applied to the inner peripheral surface of the tire. It is preferable that the

After manufacturing a sealant tire having a sealant layer on the inner side of the inner liner in the tire radial direction by the above-described manufacturing method, that is, the substantially string-shaped sealant material is continuously spirally formed into the vulcanized and molded tire. After forming a sealant layer on the radially inner side of the inner liner in the tire radial direction by the step of applying to the peripheral surface, the step of applying the sealant material and then attaching the sound absorbing layer is performed.

<Step of attaching sound absorbing layer>
In the step of attaching the sound absorbing layer, the sound absorbing layer is provided inside in the tire radial direction of the sealant layer formed inside the inner liner in the tire radial direction. Since the sealant material forming the sealant layer has adhesive strength, it is possible to easily provide the sound absorbing layer inside the sealant layer in the tire radial direction by bringing the sound absorbing layer into contact with the sealant layer. Thus, in the step of attaching the sound absorbing layer, the sound absorbing layer is attached with the sealant material applied to the inner peripheral surface of the tire.

In the step of attaching the sound absorbing layer, it is preferable to attach the sound absorbing layer having the necessary dimensions to a holder and attach it to the tire. As a result, a sealant tire to which a sound absorbing layer is adhered can be manufactured more productively.

From the viewpoint of production efficiency, it is preferable that in the step of attaching the sound absorbing layer, the sound absorbing layer is continuously introduced into the tire from the opening of the tire and then attached, and one sound absorbing layer is continuously attached to the tire.

FIG. 10 schematically shows an example of a cross section of a sealant tire in which a sound absorbing layer is provided inside the sealant layer in the tire radial direction. In FIG. 10 , the sound absorbing layer 25 is provided inside the sealant layer 22 in the tire radial direction.

The width of the sealant layer (the length of the sealant layer in the tire width direction, the length represented by W ₁ +6×W ₀ in FIG. 6, and the length represented by W _s in FIG. 10) is not particularly limited, but the effect is From the reason that it can be obtained more preferably, it is preferably 85 to 115% of the tire breaker width (the length of the breaker in the tire width direction, the length shown by W _b in FIG. 10), and 95 to 105%. It is more preferable to have

The width of the sound absorbing layer (the length of the sound absorbing layer in the tire width direction, the length indicated by W _a in FIG. 10) is not particularly limited, but the width of the sealant layer ( The length of the sealant layer in the tire width direction, the length represented by W ₁ + 6 × W ₀ in FIG. 6, and the length represented by W _s in FIG. More preferably 90%.

It is preferable that the length of the sound absorbing layer in the tire width direction is substantially constant. This makes it easy to automate the process of providing the sound absorbing layer (creating and attaching the sound absorbing layer), which is effective in reducing costs.
Here, in this specification, the length is substantially constant, the length variation is 95 to 105% (preferably 97 to 103%, more preferably 98 to 102%, more preferably 99 to 101% ).

Although the thickness of the sound absorbing layer is not particularly limited, it is preferably 1.0 to 150 mm, more preferably 30 to 120 mm.

The sound absorbing layer is advantageous in terms of tire uniformity, moldability of the three-dimensional network structure, material size processing, transportation, production workability, and cost. A cross-sectional shape is preferred.
Here, the term “substantially constant width” means that the variation in the length of the sound absorbing layer in the tire width direction is 95 to 105% (preferably 97 to 103%, more preferably 98 to 102%, still more preferably 99 to 101%). means to fit.
The term "substantially constant cross-sectional shape" means that the cross-sectional shape of the sound absorbing layer is substantially constant. Cross section cut by a plane including the width direction and radial direction) of the cross section of the cross section of the sound absorbing layer shown in FIG. to 102%, more preferably 99 to 101%).

Although it is preferable for the sound absorbing layer to have no joints from the viewpoint of keeping the weight constant in the tire circumferential direction, the manufacturing cost of the seamless annular sound absorbing layer is very high. Therefore, the cost and the performance can be balanced by attaching the substantially rectangular sound absorbing layer so that the seams are small. At the seams (end surfaces in the circumferential direction of the sound absorbing layers), the sound absorbing layers may overlap or may have gaps.

Although the number of seams is not particularly limited, one or two is preferable, and one is more preferable. The number of seams being 1 means that the sound absorbing layer is composed of one sound absorbing layer.
The gap length of the seam (the gap or overlapping portion of the sound absorbing layers) is preferably 80 mm or less, more preferably 20 mm or less, and even more preferably 10 mm or less. If it exceeds 80 mm, tire uniformity tends to deteriorate. Moreover, the gap length of the joint is preferably 1 mm or more from the viewpoint of manufacturing cost. When two seams are provided, the circumferential length ratio of the sound absorbing layer is preferably 3% or less, more preferably 1% or less. 3% or less corresponds to placing a small piece to fill the gap.

The circumferential end surface of the sound absorbing layer is preferably substantially perpendicular to the inner surface of the tire tread in terms of ease of processing.
Here, substantially vertical means that the angle is 70-100% (preferably 89-91%).

It is preferable that the seams of the sound absorbing layer have a taper angle of 1 or 2 with respect to the inner surface of the tire tread. By providing the taper, the gap between the sound absorbing layers can be narrowed in appearance, and adhesion of foreign matter can be prevented. In addition, although the seam portion of the sound absorbing layer is the portion where stress is most applied, separation of the sound absorbing layer can be suppressed by providing a taper.

The circumferential end face (taper angle) of the sound absorbing layer is preferably 10 to 80°, more preferably 15 to 45°, with respect to the inner surface of the tire tread. If it is less than 10°, processing is difficult, and if it exceeds 80°, the sound absorbing layer tends to peel off due to long-term running. tends to be

It is desirable that the surface of the sound absorbing layer in contact with the sealant layer, that is, the adhesive surface is substantially flat. Thereby, it is possible to increase the bonding area and obtain good adhesiveness.
Here, "substantially flat" means that the variation of the surface of the sound absorbing layer in contact with the sealant layer is within ±2 mm (preferably ±0.5 mm).

The surface of the sound absorbing layer opposite to the surface in contact with the sealant layer, i.e., the exposed top surface, can still provide a sound absorbing effect even if the surface is flat. Since the effect is high, it is preferable to have a thick portion if the width and volume are the same. In other words, the thickness of the sound absorbing layer at the widthwise end portions of the tire is preferably smaller than the thickness at the widthwise central portion of the tire for the reason that good road noise reduction is obtained.

In areas where the thickness of the sound absorbing layer is large, even if there is a taper, the sound absorbing layer may peel off, but in areas where the thickness is small, the peeling force of the sound absorbing layer is small, so it is difficult to peel off and has the effect of blocking the peeling. I understood it. Therefore, from the viewpoint of preventing separation of the sound absorbing layer, it is preferable that the thickness of the sound absorbing layer at the widthwise end portions of the tire is smaller than the thickness at the widthwise central portion of the tire.

When the thickness of the upper surface of the sound absorbing layer is different, if the shape of the thick part and the thin part can complement each other, it is possible to process the middle of one sound absorbing layer. A set of sound absorbing layers can be made and less waste can be produced.

The sound absorbing layer is not particularly limited as long as it contains a three-dimensional network structure as a sound absorbing material. In particular, as described above, the sound absorbing layer is preferably composed only of the three-dimensional network structure, because better road noise reduction can be obtained.

If the cross-sectional area ratio of the three-dimensional network structure to the tire cavity, that is, the cross-sectional area of the three-dimensional network structure/the cross-sectional area of the tire cavity×100, is low, the sound absorption performance is low. 2% to 90% is preferable, 5% to 70% is more preferable, and 20% to 70% is even more preferable. Here, in order to change the cross-sectional area ratio, for example, the width and thickness of the three-dimensional network structure may be changed.
In this specification, the cross-sectional area of the three-dimensional network structure is the apparent cross-sectional area of the three-dimensional network structure, which is determined from the outer shape of the three-dimensional network structure including the internal cavities. The cross-sectional area of the three-dimensional network structure is calculated by dividing the volume of the three-dimensional network structure by the average thickness of the three-dimensional network structure (thickness in the radial direction of the tire). Here, the volume of the three-dimensional network structure is the apparent total volume of the three-dimensional network structure, and refers to the volume determined from the outer shape of the three-dimensional network structure including the internal cavities. Further, the average thickness of the three-dimensional network structure also means the average thickness determined from the outer shape of the three-dimensional network structure including the internal cavities.
Further, in this specification, the cross-sectional area of the tire lumen is calculated by dividing the total volume of the tire lumen calculated as follows by the height of the tire lumen in the tire radial direction.
The total volume (V1) of the tire lumen is approximately determined by the following formula when the assembly is filled with normal internal pressure and no load is applied.
V1=A×{(Di−Dr)/2+Dr}×π
In the formula, A is the area of the bore in one tire meridian cross section obtained by CT scanning the tire in the normal state, where the bore is the tire rotation axis on both sides of the tire equator. A virtual space (closed region) formed by a straight line connecting close points and the tire inner peripheral surface (inner wall surface), Di is the maximum outer diameter of the tire lumen in a normal state, Dr is the rim diameter, and π is is pi.

If the apparent density of the three-dimensional network structure is low, the sound absorption performance is low. 10 to 250 kg/m ³ is preferred, 20 to 200 kg/m ³ is more preferred, and 30 to 100 kg/m ³ is even more preferred, since there is a risk of becoming susceptible to damage.
In this specification, the apparent density is a density calculated by regarding the cavities existing inside the three-dimensional network structure as the volume of the three-dimensional network structure, and the mass of the three-dimensional network structure is It is calculated by dividing by the apparent total volume of the body (the volume determined from the outer shape of the three-dimensional network structure including the internal cavities). Specifically, it can be calculated by preparing a cubic measurement sample of approximately 1 m×1 m×1 m using a three-dimensional network structure and measuring the mass of the prepared measurement sample.

The 25% compression hardness of the three-dimensional network structure is preferably 20-250N, more preferably 60-220N. When the 25% compression hardness is within the above range, a good road noise reduction property can be obtained without adversely affecting the sealing performance, and the tire is less likely to be damaged when a nail or the like is stuck in the tire.
In the present specification, the 25% compression hardness of the three-dimensional network structure is measured using a perfectly circular pressure plate with a diameter of 200 mm according to JIS K6400-2.

Preferably, the filars are hollow fibers. This provides better road noise reduction.

The hollowness ratio of the filament is preferably 10 to 90%, more preferably 20 to 80%, for the reason that it is more excellent in sealing performance and road noise reduction performance.
In this specification, the hollowness of the filaments refers to the total area (Sa) of the cross section taken perpendicular to the filament axis (fiber axis) of the filaments (cross section). A value obtained by measuring the area of the hollow portion (Sb) and calculating it using the following formula. However, Sb means the sum of the areas of the respective hollow portions when it has a plurality of hollow portions.
Hollow ratio (%) = (Sb/Sa) x 100

The average diameter of the filaments (average fiber diameter) is not particularly limited, but is preferably 0.1 to 5.0 mm, more preferably 0.3 to 2.0 mm. By setting the average diameter of the filament within the above range, a sufficient noise reduction effect can be obtained, and the tire can be made less susceptible to damage when a nail or the like is stuck in the tire.
The average diameter of the filaments can be determined by image analysis of scanning atomic force micrographs, image analysis of scanning electron micrographs, image analysis of transmission micrographs, analysis of X-ray scattering data, pore electric resistance method (Coulter principle method), etc.
The diameter of the filament means the apparent diameter (diameter including cavity) of the cross section perpendicular to the filament axis (fiber axis) of the filament.

A method for producing a three-dimensional network structure will be described below.
The three-dimensional mesh structure is
a descending step of extruding and lowering a filament assembly composed of a plurality of filaments, in which a molten resin is extruded downward from a die having a plurality of extrusion holes arranged in a substantially circular region;
An inclined surface of an outer circumference chute surrounding the outer circumference of the filament aggregate below the mouthpiece, sloping downward toward the inside of the filament assembly and having a substantially ring-shaped outer periphery forming portion at the lower end. A welding step of bending and forming into a substantially loop shape by contacting the above, and irregularly entangling the adjacent filaments and welding them;
a cooling step of cooling the entangled outer peripheral portion with cooling water supplied onto the inclined surface of the outer peripheral chute;
an outer peripheral portion forming step of forming the outer peripheral portion by the outer peripheral forming portion while guiding the entangled outer peripheral portion obliquely downward by the outer peripheral chute;
an internal forming step of forming the inside of the filament aggregate into water so as to bend it into a substantially loop shape, and irregularly entangling and welding the adjacent filaments in the vicinity of the water surface;
a cooling and solidifying step of cooling and solidifying the filament assembly by submerging it in water while taking it with a take-up machine below the outer circumference chute at a speed slower than the descending speed of the filament assembly;
It is manufactured by a manufacturing method including a cutting step of cutting the filament aggregate into a desired length to form a three-dimensional network structure of long members having both ends.

The three-dimensional network structure is formed by irregularly entangling a plurality of filaments made of molten resin and welding (heat welding) the entangled portions. As shown in FIG. 11, the three-dimensional mesh structure manufacturing apparatus 600 includes a mouthpiece 610, a peripheral chute 631 arranged below the mouthpiece 610, and an end of a water supply portion arranged above the peripheral chute 631. A water supply port 620 and a take-up device 650 arranged below the outer circumference chute 631 are provided. Each part will be described below.

The die 610 has a plurality of extrusion holes 611 arranged in a substantially rectangular shape, and is integrally provided below a die 612 that pressurizes and temporarily stores the molten resin. By ejecting the filaments 660 from the respective extrusion holes 611, a filament assembly 661 having a cross-sectional shape in the descending direction corresponding to the arrangement of the extrusion holes 611 in the mouthpiece 610 is ejected and lowered. Since the extrusion holes 611 are arranged in a substantially circular region as shown in FIG. 12, the filament assembly 661 as a whole descends in a substantially cylindrical shape.

As shown in FIGS. 11 and 13(a) and (b), the outer chute 631 is arranged below the mouthpiece 610 and surrounds the outer circumference 662 of the descending filament aggregate 661 . The outer circumference chute 631 has a sloped surface 632 that slopes downward toward the inside 663 of the filament assembly 661, and a substantially ring-shaped outer circumference molded portion 633 formed at the lower end. Here, if the space surrounded by the outer periphery molding portion 633 is defined as a molding opening 634, the molding opening 634 is similar in shape to the substantially circular area of the arrangement of the extrusion holes 611 in the mouthpiece 610, and is slightly smaller than this. Become. These substantially circular regions include not only perfect circles but also ellipses, oval shapes, and the like.

The water supply port 620 is provided in the supply pipe 621 extending over substantially the entire width in the circumferential direction above the outer circumference chute 631 and supplies cooling water to the inclined surface 632 (see FIG. 11). The supply pipe 621 is upstream connected to a water supply source (not shown).

The take-up machine 650 consists of a pair of take-up machines 650a and 650b. As shown in FIG. 11, the pair of take-up devices 650a and 650b are arranged facing each other below the outer circumference chute 631, and are provided with endless belts 651a and 651b provided so as to be in contact with the outer circumference 662 of the filament assembly 661, It has pulleys 653a and 654a for driving the belt 651a and pulleys 653b and 654b for driving the endless belt 651b. The pair of take-up machines 650a and 650b are respectively composed of drive motors, chains and gears for driving the pulleys 653a and 654a or the pulleys 653b and 654b, and also change the rotation speed of the endless belt 651a or the endless belt 651b. It has a drive control device (not shown) composed of a transmission, a control device, other gauges, and the like. A pair of take-up machines 650 a and 650 b are provided inside the water tank 640 . It is preferable that the space between the pair of endless belts 651a and 651b can be freely moved. Although the take-up device 650 uses an endless belt to take up the filament assembly 661, it is not limited to this, and a roller or the like can be used.

The water tank 640 is for submerging a predetermined portion of the three-dimensional network structure manufacturing apparatus 600 in water to cool and solidify the filament assembly 661 in a molten state. The water level of the water tank 640 is appropriately adjusted with the same height as the lower end of the outer circumference chute 631 being the lower limit.

A method for manufacturing a three-dimensional network structure will be described below with reference to FIG. Since detailed descriptions of known components are omitted, Japanese Patent No. 4350286, U.S. Pat. S. Patent no. 7,625,629.

First, a raw material containing resin as a main raw material is melted. The melted raw material is sent to the inside of the die 612 , is pressurized, and is extruded downward from the extrusion hole 611 of the lower die 610 to form the filament 660 . The temperature range inside the die can be set to 100 to 400° C., and the extrusion rate can be set to 20 to 200 kg/hour. The pressure inside the die is, for example, the discharge pressure of a 75 mm screw, and the pressure range is about 0.2 to 25 MPa. When manufacturing a three-dimensional network structure having a thickness exceeding 100 mm, it is preferable to uniform the die pressure by using a gear pump or the like. Each filament 660 ejected from the mouthpiece 610 becomes a filament aggregate 661 composed of a plurality of filaments 660 due to the arrangement of a plurality of extrusion holes 611 . Note that the above numerical values are only an example, and other conditions can be appropriately selected according to the raw material of the resin, the design of the product, and the like.

Of the filament assembly 661, the filament 660 located on the outer peripheral portion 662 is grounded on the inclined surface 632 of the outer peripheral chute 631, and the vertical drop trajectory is disturbed by the contact, and the adjacent filament 660 and the adjacent filament 660 are looped. While getting entangled with the water, it rides on the flow of cooling water supplied from the supply pipe 621 and slides down the inclined surface 632 . At this time, the filaments 660 are directly affected by gravity and are two-dimensionally entangled along the inclined surfaces 632 . An outer peripheral portion 662 of the filament assembly 661 that has slid down the inclined surface 632 is formed by the outer peripheral forming portion 633 when passing through the forming opening 634 . The smaller the molding opening 634 compared to the substantially circular area of the arrangement of the extrusion holes 611 in the die 610, the deeper and more densely formed the outer peripheral portion 662 toward the inner portion 663. Also, if the outer peripheral molded portion 633' is set long as shown in FIG. 14A, the range toward the inner portion 663' of the outer peripheral portion 662' is shallow but densely formed. As shown in FIG. 14(b), when the outer peripheral molded portion 633' is provided at the corner, the bulk density of the outer peripheral portion 662' hardly increases as compared with the inner portion 663', and the surface becomes soft.

Of the filament assembly 661 , the filament 660 that has fallen without contacting the inclined surface 632 passes through the forming opening 634 . At this time, among the filaments 660 passing through the molding opening 634, those that pass near the outer peripheral molding portion 633 come into contact with the filaments 660 sliding down the inclined surface 632, become entangled in a loop, and further contact with each other. Disturbance of the drop trajectory due to the entanglement propagates to the adjacent filaments 660 in the central direction while dropping. Of the filaments 660 passing through the forming opening 634, those that pass near the center of the forming opening 634 land on the water surface without being entangled as described above. Here, since the retrieving speed by the retrieving device 650 is slower than the falling speed of the filament assembly 661, the filament 660 that has landed on the water is bent and entangled in a substantially loop shape near the water surface.

In this way, the filament assembly 661 is formed into a three-dimensional mesh (three-dimensional mesh) structure, cooled in the water tank 640, and taken up by the take-up machine 650 and lowered. The outer peripheral portion 662, which has come into contact with the cooling water at the outer peripheral chute 631, is not yet completely solidified at that time, but is submerged in the water tank 640 to be cooled and fixed in shape.

A three-dimensional network structure can be obtained by continuing the above operations and cutting the obtained three-dimensional network structure into a desired length. The three-dimensional mesh structure becomes an elongated member having a cross section similar to the shape of the molded opening 634 and having both ends generated by cutting. The three-dimensional network structure is formed by randomly entangling and welding a plurality of filaments 660 in a loop shape, and is flexible with appropriate elasticity.

In the above description, the arrangement of the extrusion holes 611 in the mouthpiece 610 and the case where the molding openings 634 are substantially circular were described. may be changed as appropriate to the shape of Other conditions such as the diameter of the filaments, the number of extrusion holes, and the installation density of the extrusion holes may also be appropriately changed according to the properties and shape of the desired three-dimensional network structure.
In order to form the filament into a hollow fiber, a known technique may be adopted. For example, the extrusion hole may have a cross-sectional shape having a solid portion. As a cross-sectional shape having a solid portion, for example, a donut-shaped cross-sectional void portion may be used.

A thermoplastic resin can be preferably used as the raw material resin of the three-dimensional network structure. The thermoplastic resin is not particularly limited, and includes polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 66 and Kevlar, fluororesins such as Teflon (registered trademark), polyurethane, and polychloride. Examples thereof include vinyl, polystyrene, polyacrylonitrile, polyvinyl alcohol, polyimide, copolymers and elastomers copolymerized based on the above resins, and blends of the above resins. Among them, polyester-based resins (resins having a polyester structural unit) are preferable because the effect can be obtained more preferably, a more preferable 25% compression hardness can be obtained, and the inhibition of sealability can be more suitably suppressed. For that reason, copolymers of polyesters and aliphatic polyethers are more preferred, and copolymers of polybutylene terephthalate and aliphatic polyethers are even more preferred.
Aliphatic polyethers include units represented by —(CH ₂ ) _m O— (m: integer). m is the same or different, preferably 1-20, more preferably 1-10, still more preferably 2-6.

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

Various chemicals used in the examples are described below.
Butyl rubber A: Regular butyl 065 (manufactured by Nippon Butyl Co., Ltd., Mooney viscosity at 125°C ML1 + 8 = 32)
Liquid polymer A: Nisseki polybutene HV300 (manufactured by JX Nippon Oil & Energy, kinematic viscosity at 40°C: 26,000 mm ² /s, kinematic viscosity at 100°C: 590 mm ² /s, number average molecular weight: 1,400)
Liquid polymer B: Nisseki polybutene HV1900 (manufactured by JX Nippon Oil & Energy, kinematic viscosity at 40°C: 160,000 mm ² /s, kinematic viscosity at 100°C: 3,710 mm ² /s, number average molecular weight: 2,900)
Plasticizer: DOP (dioctyl phthalate, manufactured by Showa Chemical Co., Ltd., specific gravity 0.96, viscosity 81 mPs S)
Carbon black: N330 (manufactured by Cabot Japan Co., Ltd., HAF grade, DBP oil absorption 102 ml/100 g)
Crosslinking aid: Barnok GM (manufactured by Ouchi Shinko Chemical Co., Ltd., p-benzoquinonedioxime)
Cross-linking agent: Nyper NS (manufactured by NOF Corporation, dibenzoyl peroxide (40% diluted product, dibenzoyl peroxide: 40% dibutyl phthalate: 48%), the amount in Table 1 is pure benzoyl peroxide)
Polyurethane sponge: ESH2 (polyurethane) manufactured by INOAC Corporation
Belprene: Belprene P type manufactured by Toyobo Co., Ltd. (polybutylene terephthalate and aliphatic polyether copolymer, aliphatic polyether: unit represented by —(CH ₂ ) ₄ O—))

(Manufacturing example)
<Production of three-dimensional network structure>
Using velprene as the resin, a three-dimensional network structure was produced according to the production method described above. The apparent density, hollowness, and the like of the three-dimensional network structure were adjusted by varying the number of extrusion holes, the installation density of the extrusion holes, and the like. The average diameter (average fiber diameter) of the filaments forming the obtained three-dimensional network structure was 0.8 mm. Hollow fibers were used as filaments.

Table 2 shows the properties of the obtained three-dimensional network structure.

(Comparative example 1)
A tire of Comparative Example 1 (215/55R17, 94W, rim: 17×7.5J, cross-sectional area of tire lumen when assembled with tire rim: 194 cm ² ) was used.
(Example 1)
<Tire manufacturing>
According to Table 2, a sound absorbing layer (length 2000 mm) made of the three-dimensional network structure described in Table 2 was applied to a tire (215/55R17, 94 W, rim: 17 X 7.5 J, cross-sectional area of tire lumen when assembled with tire rim: 194 cm). ² ), and the tire of Example 1 was obtained.
(Comparative example 2)
<Tire manufacturing>
According to Table 2, the polyurethane sponge described in Table 2 was used in place of the three-dimensional network structure of Example 1 to prepare a tire of Comparative Example 2.

(Comparative Examples 3-4, Examples 2-16)
<Manufacture of sealant tires>
According to the formulation shown in Table 1, butyl rubber A, carbon black and a cross-linking aid are supplied from the upstream supply port of the twin-screw kneading extruder, liquid polybutene B is supplied from the midstream supply port, and liquid polybutene A and a plasticizer are supplied from the downstream supply port. and a cross-linking agent were added and kneaded under conditions of a barrel temperature of 100° C. and 200 rpm to prepare a sealant material. As for the liquid polybutene, the liquid polybutene at 50° C. was introduced from the supply port.
(Kneading time of each material)
Mixing time of butyl rubber A, carbon black and cross-linking aid: 2 minutes Mixing time of liquid polybutene B: 2 minutes Mixing time of liquid polybutene A, plasticizer and cross-linking agent: 1.5 minutes

According to Table 2, the tire (215/55R17, 94W, rim: 17X7.5J, cross-sectional area of tire cavity when assembled with tire rim: 194 cm ² , vulcanization molded, tire rotation speed 12 m/min.) , preheating temperature: 40 ° C, tire breaker width: 180 mm), sealant material (viscosity 4000 Pa s (90 ° C), approximately string-like shape, thickness 3 mm, width 4 mm) with a thickness of 3 mm, the width of the pasting area A sealant material (temperature: 100°C) that is prepared in sequence is extruded from a twin-screw kneading extruder so as to have a thickness of 180 mm, and is continuously spirally applied to the inner peripheral surface of the tire through a nozzle according to FIGS. 1 to 4. (coated in a spiral) to form a sealant layer. Furthermore, according to Table 2, in Comparative Example 4 and Examples 2 to 16, a sound absorbing layer made of the polyurethane sponge described in Table 2 or the three-dimensional network structure described in Table 2 was placed on the radially inner side of the formed sealant layer. (Length 2000 mm) was installed using the adhesiveness of the sealant material so that the gap between the circumferential end faces of the sound absorbing layer was 10 mm.
The width of the sealant material was adjusted so as to be substantially constant in the length direction. Also, the viscosity of the sealant material was measured with a rotary viscometer at 90° C. in accordance with JIS K 6833.
Moreover, in Example 2, in order to eliminate the tackiness of the surface of the sealant layer, the surface of the sealant layer was covered with a poly film, and then the sound absorbing layer was installed.

The obtained tires were evaluated as follows, and the results are shown in Table 2.

<Sound absorption effect (road noise reduction)>
Inside the vehicle (2400 cc, FF domestic vehicle) with tires installed on all wheels (internal pressure: 230 kPa) and running on a road noise measurement road (rough asphalt road) at a speed of 60 km / h, at the ear position on the driver's seat window side The peak of the sound (air column resonance sound in the narrow band around 210 Hz) was measured. The higher the numerical value, the better the road noise reduction performance.

<Durability test (durability performance)>
Under the condition of a load of 5.0 Kn, a tire (internal pressure: 230 kPa) was run on a drum (1.7 m) for 10,000 km at a speed of 100 km/h, and damage to the sound absorbing layer was visually confirmed.

<Air seal test (sealability)>
Set the initial internal pressure of the tire to 230 kPa, set the atmospheric temperature to 25 ° C., use a round nail of JIS N100 (body diameter 4.0 mm, length 10 cm), drive 36 nails into the groove of the tire to the head, and after 5 minutes After the nails were removed, the tire was left at an ambient temperature of 25° C. for a whole day, and soapy water was applied to the tire to check the number of nail holes that did not leak air.
A larger index indicates better sealing performance.

The pneumatic tire of the example in which the sound absorbing layer having the three-dimensional mesh structure as a sound absorbing material was provided in the tire lumen was excellent in reducing road noise. In addition, the pneumatic tires (sealant tires) of Examples 2 to 16, which have a sound absorbing layer having a three-dimensional network structure as a sound absorbing material in the tire lumen and further have a sealant layer inside the inner liner in the tire radial direction (sealant tire), have a seal performance and road noise reduction.

By comparing Comparative Examples 1 and 2 and Example 1, it was found that the three-dimensional network structure can be used as a sound absorbing material like a sponge.
Further, by comparing Comparative Example 4 and Example 3, it was found that the use of the three-dimensional network structure as a sound absorbing material does not adversely affect the sealing performance.
Further, from Examples 1 to 3, it was found that a part of the three-dimensional network structure was damaged when the three-dimensional network structure was not fixed.

10 Tire 11 Inner peripheral surface of tire 14 Tread portion 15 Carcass 16 Breaker 17 Band 20 Sealant material 21 Wide portion 22 Sealant layer 25 Sound absorbing layer 30 Nozzle 31 Nozzle tip 40 Non-contact displacement sensor 50 Rotary drive device 60 Twin-screw kneading extrusion Machine 61 (61a 61b 61c) Supply port 62 Material feeder d, d ₀ , d ₁ , d ₂ Distance between the inner peripheral surface of the tire and the tip of the nozzle 600 Manufacturing device 610 Die 611 Extrusion hole 612 Die 620 Water supply port 621 Supply Pipe 631 Peripheral chute 632 Inclined surface 633, 633' Peripheral forming part 634 Forming opening 640 Water tank 641 Water surface 650 (650a, 650b) Take-up machine 653a, 654a, 653b, 654b Pulleys 651a, 651b Endless belt 660 Wire 661 Wire assembly Body 662, 662' Peripheral portion 663, 663' Inside

Claims (8)

A three-dimensional network structure having an average diameter of 0.1 to 5.0 mm of the filaments formed by a plurality of filaments of molten resin being irregularly entangled and the entangled portions being welded. Equipping the inner cavity of the tire with a sound absorbing layer having a sound absorbing material ,
The three-dimensional network structure has cavities between the entangled filaments,
The sound absorbing layer is fixed to the tire,
The length of the sound absorbing layer in the tire width direction is substantially constant, and the length is substantially constant means that the variation in length is within 95 to 105%,
A pneumatic tire , wherein the sound absorbing layer has a thickness of 1.0 to 150 mm . The pneumatic tire according to claim 1, having a sealant layer inside the inner liner in the tire radial direction. Having the sound absorbing layer inside the tire radial direction of the sealant layer,
The sealant layer is composed of a sealant material,
3. The pneumatic tire according to claim 2, wherein said sound absorbing layer is fixed by said sealant material. The pneumatic tire according to any one of claims 1 to 3, wherein the three-dimensional network structure has an apparent density of 10 to 250 kg/m ³ . The pneumatic tire according to any one of claims 1 to 4, wherein the resin is a thermoplastic resin. The pneumatic tire according to any one of claims 1 to 5, wherein the resin is a polyester resin. The pneumatic tire according to any one of claims 1 to 6, wherein the filaments are hollow fibers. 4. The pneumatic tire according to claim 2, wherein the sealant layer is composed of a substantially string-shaped sealant material continuously spirally arranged along the inner peripheral surface of the tire.

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