Tire with functional component

Abstract

To provide a tire which includes a storage body storing a functional component on a tire inner surface of a tread part, is excellent in sensing accuracy of a sensor function possessed by the functional component and durability of the storage body, and maintains long-term deterioration resistance of the storage body.SOLUTION: A tire with a functional component includes a storage body storing a functional component on a tire inner surface of a tread part, wherein the functional component has at least a contact surface contacting the tire inner surface and a sensor function for detecting tire information, the storage body is composed of a rubber component containing 40 mass% or less of natural rubber (NR) and 60 mass% or more of butyl rubber (IIR), and 10 to 38 pts.mass of carbon black is contained with respect to 100 pts.mass of the rubber component.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a tire provided with a functional component having a sensor function for detecting tire information on the inner surface of the tire.

Background Art

[0002] In order to detect tire information, functional components having a sensor function (such as electronic components such as sensor units) are disposed in tires. In particular, due to ease of detecting air pressure and wear, such functional components are disposed on the inner surface of the tread portion of the tire (for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, the housing for housing the functional component disposed on the inner surface of the tread portion of the tire is likely to be subjected to forces due to the rotation of the tire during running and impacts from the road surface, etc., and thus there are problems in terms of durability. And, in Patent Document 1 and Patent Document 2, tires are disclosed in which peeling from the tire surface of an electronic component mounting member (housing), etc. hardly occurs even when a large impact is applied during high-speed running or during high-speed running in a low-temperature environment, but these have room for improvement from the viewpoints of the rubber physical properties of the members constituting the tire, the mounting position of the electronic component mounting member (housing) being restricted, and the aging deterioration property. Further, this functional component is difficult to stably sense the sensing accuracy of the sensor function due to the influence of the rotation of the tire during running, etc., and there is also room for further improvement in this regard.

[0005] Therefore, an object of the present invention is to provide a tire having a container housing functional components on the inner surface of the tread portion of the tire, excellent in sensing accuracy of the sensor function of the functional components and durability of the container, and further maintaining the aging deterioration property of the container.

Means for Solving the Problems

[0006] In order to solve the above problems, the present inventor has intensively studied and provided a container housing functional components on the inner surface of the tread portion of the tire. The functional components have at least a contact surface that contacts the inner surface of the tire and a sensor function for detecting tire information. The container is composed of a rubber component containing 40% by mass or less of natural rubber (NR) and 60% by mass or more of butyl rubber (IIR), and further contains 10 to 38 parts by mass of carbon black with respect to 100 parts by mass of the rubber component. It has been found that such a tire has excellent sensing accuracy of the sensor function of the functional components and durability of the container, and further maintains the aging deterioration property of the container, and the present invention has been completed.

[0007] That is, the present invention is as follows <1> to <7>. <1> A tire provided with a container housing functional components on the inner surface of the tread portion of the tire, The functional components have at least a contact surface that contacts the inner surface of the tire and a sensor function for detecting tire information, The container is composed of a rubber component containing 40% by mass or less of natural rubber (NR) and 60% by mass or more of butyl rubber (IIR), and further contains 10 to 38 parts by mass of carbon black with respect to 100 parts by mass of the rubber component. <2> The average value of the nitrogen adsorption specific surface area (N 2 SA) of the carbon black is less than 50 m 2 / g. The tire according to <1>. <3> The container further contains 3 to 85 parts by mass of a white filler with respect to 100 parts by mass of the rubber component. The tire according to <1> or <2>. <4>The tire according to any one of <1> to <3>, wherein the rubber component contains 80% by mass or more of the butyl rubber (IIR). <5>The tire according to any one of <1> to <4>, wherein the container is fixed to the inner surface of the tire. <6>The tire according to <5>, wherein the container is fixed to the inner surface of the tire by an adhesive. <7>The tire according to any one of <1> to <6>, wherein the sensor function of the functional component is a sensor function using a piezoelectric element as a sensor element.

Advantages of the Invention

[0008] According to the present invention, it is possible to obtain a tire having a container containing a functional component on the inner surface of the tire in the tread portion, excellent in the sensing accuracy of the sensor function of the functional component and the durability of the container, and further maintaining the secular deterioration property of the container.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0010] The present invention will be described. The present invention provides a tire having a container in which functional components are housed on the inner surface of the tread portion of the tire. The functional components have at least a contact surface that contacts the inner surface of the tire and a sensor function for detecting tire information. The container is made of a rubber component containing 40% by mass or less of natural rubber (NR) and 60% by mass or more of butyl rubber (IIR). Further, the tire contains 10 to 38 parts by mass of carbon black per 100 parts by mass of the rubber component. Hereinafter, this will also be referred to as "the tire of the present invention".

[0011] In the present invention, the numerical range represented by "~" means a numerical range in which the numerical value described before "~" is the lower limit value and the numerical value described after "~" is the upper limit value, unless otherwise specified.

[0012] Hereinafter, the configuration, contained components and their contents of the container provided in the tire of the present invention, the configuration of the tire of the present invention (as a whole), etc. will be described in detail with reference to the drawings. Note that the dimensional ratios (length, thickness, etc.) and orientations of each member shown in the drawings may be different from the actual dimensional ratios and orientations in order to facilitate understanding of the invention. Also, some reference signs may be omitted.

[0013] [Container] The container provided in the tire of the present invention is made of a predetermined rubber component. The container is provided on the inner surface of the tread portion of the tire and houses a functional component having a sensor function for detecting tire information so as to have a contact surface that contacts the inner surface of the tire. For example, as shown in FIGS. 1 to 3, the base portion 31 of the container 30 is joined and fixed to the inner surface 12 of the tread portion 1 of the tire (the inner surface 12 joined to the base portion 31 is omitted in FIGS. 2 and 3). The accommodating portion 33 houses the functional component 20 so as to be surrounded by the side wall 32. Further, an embodiment is shown in which the housed functional component 20 has a contact surface 21 that contacts the inner surface 12 of the tread portion 1 via the base portion 31.

[0014] Here, the meaning of the accommodation body being "provided on the inner surface of the tire in the tread portion" is that the accommodation body is connected and arranged on the inner surface of the tire in the tread portion (the inner circumferential surface of the tire at a position facing the tread surface of the tread portion). Also, the meaning of the functional component having "a contact surface that contacts the inner surface of the tire (in the tread portion)" includes not only the embodiment where the functional component has a contact surface that directly contacts the inner surface of the tire in the tread portion, but also the embodiment where the functional component has a contact surface that contacts through a member (the base portion 31 in the embodiment of FIG. 1) that is in surface contact with the inner surface of the tire in the tread portion in the accommodation body. That is, the embodiment where the functional component is in direct surface contact with the inner surface of the tire in the tread portion, and the embodiment where the functional component is in surface contact through a member that is in surface contact with the inner surface of the tire in the tread portion in the accommodation body are included.

[0015] And it is more preferable that the accommodation body containing this functional component is fixed to the inner surface of the tire in the tread portion (in a state where the position of the accommodation body does not substantially change), and further, it is more preferable that this is an embodiment where the accommodation body is fixed to the inner surface of the tire in the tread portion by an adhesive. As this adhesive, an epoxy-based adhesive, an acrylic-based adhesive, etc. can be used. Also, a double-sided tape or the like may be used as the adhesive.

[0016] Hereinafter, the details of each component included in this accommodation body, the physical properties of this accommodation body, etc. will be described.

[0017] <Rubber component> The container provided in the tire of the present invention is composed of a rubber component containing 40% by mass or less of natural rubber (NR) and 60% by mass or more of butyl rubber (IIR). That is, this container is composed of a rubber component, and in this rubber component, 60% by mass or more of butyl rubber (IIR) is contained and 40% by mass or less of natural rubber (NR) is contained. This rubber component is not particularly limited as long as it contains natural rubber (NR) at a content ratio of 40% by mass or less and butyl rubber (IIR) at a content ratio of 60% by mass or more, and any known rubber component used (used in combination) in applications constituting rubber products, such as diene rubbers, can be used. Examples of diene rubbers include, in addition to the natural rubber (NR) described above, for example, butadiene rubber (BR), styrene-butadiene copolymer rubber (styrene butadiene rubber, SBR), acrylonitrile-butadiene copolymer rubber (nitrile rubber, NBR), chloroprene rubber (CR), synthetic isoprene rubber (IR), styrene-isoprene copolymer rubber, isoprene-butadiene copolymer rubber, styrene-butadiene-vinyl pyridine terpolymer (VP), and the like. Furthermore, in addition to the butyl rubber (IIR) described above, it is also possible to use in combination rubber components other than diene rubbers, such as olefin rubbers (ethylene propylene rubber, acrylic rubber, etc.), fluororubbers, and silicone rubbers. Also, as the butyl rubber (IIR), recycled butyl rubber obtained by recycling from used rubber products and the like can be used.

[0018] In addition, the content ratio of natural rubber (NR) in the rubber component constituting the container provided in the tire of the present invention is more preferably less than 40% by mass, even more preferably 35% by mass or less, even more preferably 30% by mass or less, even more preferably 20% by mass or less, and even more preferably 10% by mass or less, since the effects of the present invention are more likely to be exhibited. The lower limit may be more than 0% by mass, but is more preferably 1% by mass or more, and even more preferably 5% by mass or more. Also, the content ratio of butyl rubber (IIR) in the rubber component constituting the container provided in the tire of the present invention is more preferably more than 60% by mass, even more preferably 65% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more, since the effects of the present invention are more likely to be exhibited. The upper limit is more preferably 95% by mass or less. In particular, from the viewpoint of aging resistance, an embodiment in which the rubber component constituting this container contains 20% by mass or less of natural rubber (NR) and 80% by mass or more of butyl rubber (IIR) is very suitable. In addition, the content ratio of butyl rubber (IIR) in the present invention is the content ratio of the entire butyl rubber including recycled butyl rubber when it is included (the same applies hereinafter).

[0019] Furthermore, since the effects of the present invention are more likely to be exhibited, it is even more preferable that the ratio of butyl rubber (IIR) to natural rubber (NR) in this rubber component is 1.5 times or more (IIR / NR is 1.5 or more), even more preferably this ratio is 2 times or more (IIR / NR is 2.0 or more), even more preferably 3 times or more (IIR / NR is 3.0 or more), and even more preferably 5 times or more (IIR / NR is 5.0 or more). The upper limit is not particularly limited, and it may be, for example, 50 times or less (IIR / NR is 50 or less).

[0020] <Carbon black> The container provided in the tire of the present invention contains carbon black in addition to the above-described predetermined rubber component which is a constituent component. This carbon black is not particularly limited, and any known carbon black used in applications such as rubber products can be used. Specific examples of carbon black include those of various grades such as SAF-HS, SAF, ISAF-HS, ISAF, ISAF-LS, IISAF-HS, HAF-HS, HAF, HAF-LS, FEF, GPF, SRF, FT, MT, etc. Recycled carbon black obtained by recycling from used rubber products or the like can also be used. And this carbon black may be used alone or in combination of two or more. In addition, since the effect of improving durability and the like are likely to be exhibited due to a decrease in the heat generation property of the container, the average value of the nitrogen adsorption specific surface area (N 2 SA) of this carbon black is more preferably less than 50 m 2 / g, even more preferably 45 m 2 / g or less, even more preferably 40 m 2 / g or less, even more preferably 35 m 2 / g or less. The lower limit is more preferably 10 m 2 / g or more, even more preferably 15 m 2 / g or more, even more preferably 23 m 2 / g or more because it becomes easier to suppress the dropout of functional parts.

[0021] Here, this "carbon black" means carbon fine particles composed of primary particles having a diameter of about 3 to 500 nm industrially manufactured with quality control. The nitrogen adsorption specific surface area (N 2 SA) of carbon black is a value measured in accordance with JIS K6217-2:2017. Furthermore, the "average value of the nitrogen adsorption specific surface area (N 2 SA) of carbon black" means the nitrogen adsorption specific surface area (N 2It is the value of SA), and when two or more are used in combination, it is the value obtained by multiplying the nitrogen adsorption specific surface area (N of each carbon black used by its usage ratio and then adding them together. In this calculation, the total of the usage ratios of each carbon black is set to 1.0. 2 SA) value, and when two or more are used in combination, it is the value obtained by multiplying the nitrogen adsorption specific surface area (N of each carbon black used by its usage ratio and then adding them together. In this calculation, the total of the usage ratios of each carbon black is set to 1.0.

[0022] And in this container, the above-mentioned carbon black is contained in an amount of 10 to 38 parts by mass with respect to 100 parts by mass of the rubber component constituting the container. Furthermore, the content of this carbon black is more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, even more preferably 25 parts by mass or more, and even more preferably 30 parts by mass or more with respect to 100 parts by mass of the above-mentioned rubber component. The upper limit is more preferably 35 parts by mass or less with respect to 100 parts by mass of the above-mentioned rubber component. Note that if the amount of this carbon black is less than 10 parts by mass or more than 38 parts by mass with respect to 100 parts by mass of the above-mentioned rubber component, the effects of the present invention may not be obtained. Here, the content of carbon black in the present invention means the total content of all carbon blacks including recycled carbon black when a plurality of carbon blacks are included.

[0023] <White filler> The container provided in the tire of the present invention preferably further contains a white filler. The white filler is not particularly limited, and any known white filler used in applications such as rubber products can be used. Specific examples of the white filler include, for example, silica, talc, mica, clay, calcium carbonate, etc., and silica is particularly preferred. As the silica, for example, wet silica, dry silica, fumed silica, diatomaceous earth, etc. can be used. And this white filler may be used alone or in combination of two or more. Here, this "silica" means a particulate substance composed of silicon dioxide (SiO 2 ) or having silicon dioxide as a main component (for example, containing 80% by mass or more, further 90% by mass or more).

[0024] Moreover, the container provided in the tire of the present invention preferably contains 3 to 85 parts by mass of this white filler with respect to 100 parts by mass of the rubber component constituting the container. Further, the lower limit is more preferably 5 parts by mass or more with respect to 100 parts by mass of the rubber component described above. The upper limit is more preferably 80 parts by mass or less, still more preferably 70 parts by mass or less, and even more preferably 60 parts by mass or less with respect to 100 parts by mass of the rubber component described above. In addition, when the container provided in the tire of the present invention contains a white filler, it is more preferable that the carbon black content and the white filler content both satisfy the above ranges, and the total of carbon black and white filler is 35 to 85 parts by mass with respect to 100 parts by mass of the rubber component constituting the container. The lower limit is more preferably 40 parts by mass or more with respect to 100 parts by mass of the rubber component described above, and the upper limit is more preferably 80 parts by mass or less with respect to 100 parts by mass of the rubber component described above. However, the container provided in the tire of the present invention may have a configuration that does not substantially contain a white filler.

[0025] <Other components> The container provided in the tire of the present invention may further contain, as optional components, components other than the rubber component, carbon black, and white filler described above, as long as they do not significantly affect the effects of the present invention. For example, resin components (such as terpene resin, coumarone resin, indene resin, rosin resin, etc.), zinc oxide (zinc white), oil (such as aroma oil), stearic acid, wax, lecithin, anti-aging agent, plasticizer, vulcanizing agent, vulcanization accelerator, vulcanization accelerator aid, and other various additives generally used in rubber products can be contained in an appropriate amount. As the vulcanizing agent, sulfur is typically exemplified, but as a component other than sulfur, a compound having a cross-linking function between polymers such as peroxide may also be used. Further, these may be used in combination.

[0026] For example, the contents of oil, stearic acid, zinc oxide, and resin component in this container are preferably 0.5 to 10 parts by mass, more preferably 1.0 to 8.0 parts by mass, respectively, based on 100 parts by mass of the rubber component constituting the container. And the sulfur content in this container is preferably 0.5 to 5.0 parts by mass based on 100 parts by mass of the rubber component constituting the container. Further, the content of the vulcanization accelerator in this container is preferably 0.3 to 3.0 parts by mass, more preferably 0.5 to 2.0 parts by mass, based on 100 parts by mass of the rubber component constituting the container, either with the primary accelerator alone or in a blend with the secondary accelerator.

[0027] Also, in the container provided in the tire of the present invention, when silica is used as the white filler, etc., in order to further improve the dispersibility of this silica, etc., a silane coupling agent may be further contained. This silane coupling agent is not particularly limited as long as it is a silane compound having a hydrolyzable group and an organic functional group. And this hydrolyzable group is not limited either, but for example, an alkoxy group, a phenoxy group, a carboxy group, an alkenyloxy group, etc. may be mentioned, and it is more preferable that the alkoxy group is an alkoxysilyl group bonded to a silicon atom. When the hydrolyzable group is an alkoxysilyl group, the carbon number of the alkoxy group is preferably 1 to 16, more preferably 1 to 4. Examples of the alkoxy group having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, etc.

[0028] Also, the organic functional group is not limited either, but it may be a group capable of forming a chemical bond with an organic compound. For example, an epoxy group, a vinyl group, an acryloyl group, a methacryl group, an amino group, a sulfide group (especially, a polysulfide group (-S n -: n is an integer of 2 or more)), a mercapto group, a blocked mercapto group (protected mercapto group) (for example, an octanoylthio group), etc. may be mentioned. Among them, a sulfide group (especially, a disulfide group, a tetrasulfide group), a mercapto group, and a blocked mercapto group are preferable. Such a silane coupling agent may be used alone or in combination of two or more. Further, this silane coupling agent is preferably a sulfur-containing silane coupling agent.

[0029] When silica is used as the above-mentioned white filler, it is preferably contained in an amount of 1 to 20 parts by mass, more preferably 2 to 10 parts by mass, based on 100 parts by mass of the silica.

[0030] <Tensile stress at 100% elongation at 100 °C (M100, M100 Aged)> The container provided in the tire of the present invention has the above-described configuration. Further, it is more preferable that the tensile stress at 100% elongation at 100 °C (M100) of this container is 5.0 MPa or less. This is because the container and the like are likely to have sufficient durability to withstand the forces and impacts caused by the rotation of the tire during running. This M100 is more preferably 4.0 MPa or less, still more preferably 3.0 MPa or less, and still more preferably 2.5 MPa or less. The lower limit is more preferably 1.0 MPa or more, still more preferably 1.3 MPa or more, because it is easier to further suppress the dropout of functional parts. Further, from the viewpoint of long-term deterioration properties, the tensile stress at 100% elongation at 100 °C (M100 Aged) after heat-treating this container at 70 °C for 168 h is more preferably 2.5 MPa or more, still more preferably 2.6 MPa or more, still more preferably 2.7 MPa or more, and still more preferably 3.0 MPa or more.

[0031] Here, this M100 and M100 Aged are values confirmed by a method in which a predetermined rubber test piece (for example, dumbbell No. 7 shape) is taken from the container (M100 Aged is the container after heat-treatment at 70 °C for 168 h), and a tensile test of this rubber test piece is performed in accordance with JIS K6251:2017 at a tensile speed of 500 mm / min, and the tensile stress at 100% elongation (MPa: M100) is measured at 100 °C. And by adjusting the ratio of each component and the like in the configuration as described above, this M100 or M100 Aged can be made within the above-mentioned range.

[0032] <Tensile strength at break (TB)> Moreover, the container provided in the tire of the present invention has the configuration as described above, and further, it is more preferable that the tensile strength at break (TB) of this container is 13.0 MPa or less. This is because the insertability of functional parts and the like are more likely to be enhanced. And this TB is more preferably 12.5 MPa or less, and even more preferably 12.0 MPa or less. This lower limit is more preferably 10.0 MPa or more, and even more preferably 11.0 MPa or more, because it becomes easier to highly maintain the durability of the container and more effectively suppress the dropout of functional parts.

[0033] Here, this TB is a value confirmed by a method of collecting a predetermined rubber test piece (for example, dumbbell-shaped No. 7) from the container, performing a tensile test on this rubber test piece at a tensile speed of 500 mm / min in accordance with JIS K6251:2017, and measuring the tensile strength at break (MPa: TB) at 20°C. And by adjusting the ratio of each component and the like in the configuration as described above, this TB can also be made within the above-mentioned range.

[0034] [Functional parts] As functional components to be housed in the tire housing of the present invention, there is no limitation as long as they have a sensor function for detecting tire information and can have a contact surface that contacts the inner surface of the tread portion of the tire. For example, electronic components including various sensors, transmitters, receivers, control circuits, batteries, etc. are exemplified. Examples of tire information detected and acquired by the sensor function include the internal temperature and internal pressure (air pressure) of a pneumatic tire, the wear amount of the tread portion, etc. A temperature sensor or a pressure sensor can be used for measuring the internal temperature and internal pressure. For detecting the wear amount of the tread portion, a sensor element using a piezoelectric element is disposed on the contact surface, and a functional component that detects an output voltage corresponding to the tire deformation during traveling by the sensor element and detects the wear amount of the tread portion based on the output voltage is exemplified as a preferable one. That is, it is more preferable from the viewpoint of detecting the wear amount of the tread portion that the sensor function of this functional component is a sensor function using a piezoelectric element as the sensor element. In addition, it is also possible to use an acceleration sensor or a magnetic sensor.

[0035] [Tire] The tire of the present invention has, for example, a tread portion 1 that extends in the tire circumferential direction and forms an annular shape as shown in FIG. 1, and a pair of sidewall portions 2, 2 disposed on both sides of the tread portion 1 (both ends in the tire width direction), and an embodiment including a pair of bead portions 3, 3 disposed on the inner side in the tire radial direction of the pair of sidewall portions 2 is shown.

[0036] And in this embodiment, at least one carcass layer 4 is mounted between the pair of bead portions 3, 3. This carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and is folded back from the inner side to the outer side of the tire around the bead core 5 disposed in each bead portion 3. A bead filler 6 made of a rubber composition having a triangular cross section is disposed on the outer circumference of the bead core 5.

[0037] On one side, one or more (preferably multiple) belt layers 7 are arranged on the outer peripheral side of the carcass layer 4 in the tread portion 1. These belt layers 7 include a plurality of reinforcing cords inclined in substantially the same direction with respect to the tire circumferential direction (the reinforcing cords are embedded), and when including a plurality (for example, two layers) of belt layers 7, the reinforcing cords are arranged so as to cross each other between these layers. In the belt layer 7, the inclination angle of the reinforcing cord with respect to the tire circumferential direction is set, for example, in the range of 10° to 60° at the smaller angle. As the reinforcing cord of the belt layer 7, a steel cord is preferably used. On the outer peripheral side of the belt layer 7, for the purpose of improving high-speed durability, at least one belt cover layer 8 formed by arranging reinforcing cords at an angle of, for example, 5° or less with respect to the tire circumferential direction may be arranged. As the reinforcing cord of the belt cover layer 8, organic fiber cords such as nylon and aramid are preferably used.

[0038] Furthermore, a tread rubber layer 15 is arranged in the tread portion 1. The tread rubber layer 15 includes at least a cap tread rubber layer 15A. In this embodiment, it is composed of two layers, namely, the cap tread rubber layer 15A forming the tread surface of the tread portion 1 and the under tread rubber layer 15B located on the inner side in the tire radial direction of the cap tread rubber layer 15A. Note that the tread rubber layer 15 may include a ground tread made of conductive rubber exposed on the tire contact surface and wing tips respectively arranged at both ends in the tire width direction of the cap tread rubber layer 15A.

[0039] The constituent components of the tire of the present invention (components constituting each member such as the tread portion and each layer such as the belt layer) are not particularly limited, and known components for constituting a tire such as rubber components can be arbitrarily used. Also, the tire size and the use of the tire are not particularly limited, and it is possible to make various tires such as passenger car tires, truck bus tires, and off-road tires.

[0040] The tire of the present invention is provided with a housing having the above-described configuration on the inner surface of the tire tread of the tire in such an embodiment. The arrangement position of this housing is not particularly limited as long as it is the inner surface of the tire tread, and it may be a position that does not pass through the center point in the tire width direction on the inner surface of the tire tread.

[0041] In addition, the tire of the present invention is preferably a pneumatic tire. As the gas filled in this pneumatic tire, for example, air, nitrogen, argon, an inert gas such as helium, and other gases can be used.

[0042] The tire (tire with functional parts) of the present invention having the above-described configuration has excellent sensing accuracy of the sensor function of the functional parts provided on the inner surface of the tire tread, and furthermore, the durability of the housing for accommodating these functional parts is also excellent. That is, even if repeated deformation occurs in the housing due to rotation, deformation of the tread portion, impact, etc. during tire running, damage (such as cracking or separation of members) of the housing is less likely to occur. In addition, the aging deterioration property of this housing is maintained (the durability against aging deterioration has not substantially decreased). In addition, it is also possible to make the housing less likely to undergo further aging deterioration.

[0043] Hereinafter, examples of the present invention will be described. However, the present invention is not limited to the following examples, and various modifications are possible within the technical idea of the present invention.

Example

[0044] (Production and evaluation of tires with functional parts) Each housing having the composition shown in Table 1 below and the shape shown in FIGS. 2 to 3 was produced, and this housing was bonded and fixed to the inner surface of the tire tread of a tire of tire size 235 / 50R18 97V with an adhesive as shown in FIG. 1. Furthermore, a functional part using a piezoelectric element as a sensor element was mounted on the housing so that the piezoelectric element was arranged on the contact surface in contact with the inner surface of the above tire, and tires with various functional parts were produced.

[0045] Then, for the obtained tires with functional parts of Reference Example 1, Comparative Examples 1 to 3, and Examples 1 to 5, the rubber hardness (HS), tensile stress at 100% elongation (M100), and tensile strength at break (TB) of the receptacle were measured as follows, and the sensing accuracy of the functional parts, the durability of the receptacle, and the evaluation of deterioration over time were carried out.

[0046] <Rubber hardness (HS)> A dumbbell-shaped No. 7 rubber test piece (thickness 1.0 ± 0.1 mm) was taken from the accommodating part in the receptacle of each obtained tire with functional parts, and the rubber hardness (HS) of this rubber test piece was measured at a temperature of 20°C using a Type A durometer (manufactured by Toyo Seiki Seisakusho Co., Ltd.) in accordance with JIS K6253-3:2012. These results were shown in the middle row of Table 1 below.

[0047] <Tensile stress at 100% elongation (M100)> A dumbbell-shaped No. 7 rubber test piece (thickness 1.0 ± 0.1 mm) was taken from the accommodating part in the receptacle of each obtained tire with functional parts, and for this rubber test piece, a tensile test was carried out at a tensile speed of 500 mm / min in accordance with JIS K6251:2017, and the tensile stress at 100% elongation (MPa: M100) was measured at 100°C. Also, for these, the same test was carried out after aging by hanging them in a test tank at 70°C for 168 h and heating (MPa: M100 Aged). These results were shown in the middle row of Table 1 below.

[0048] <Tensile strength at break (TB)> A dumbbell-shaped No. 7 rubber test piece (thickness 1.0 ± 0.1 mm) was taken from the accommodating part in the receptacle of each obtained tire with functional parts, and for this rubber test piece, a tensile test was carried out at a tensile speed of 500 mm / min in accordance with JIS K6251:2017, and the tensile strength at break (MPa: TB) was measured at 20°C. These results were shown in the middle row of Table 1 below.

[0049] <Sensing accuracy> For each tire with the obtained functional components, it was assembled onto a wheel with an air pressure of 230 kPa and run on a drum tester at a speed of 30 km / h, and the CV value (N = 10) of the peak height of the waveform detected by the sensor element of the functional component was measured. The results are shown in the lower part of Table 1 below. The results are expressed as an index with the value of Reference Example 1 being 100.

[0050] <Durability of the container> For each tire with the obtained functional components, as a pretreatment, oxygen was enclosed at 350 kPa and stored at 80 °C for 5 days, then assembled onto a wheel and subjected to an indoor running test on a drum tester under the running condition of increasing the speed by 10 km / h every 2 hours from 81 km / h. And the speed when the container was destroyed was taken as the test result. Note that the destruction of this container was defined as a state where the sensor function of the functional component could not be exerted due to cracks or detachment in the accommodating part of the container. The results are shown in the lower part of Table 1 below. The results are expressed as an index with the value of Reference Example 1 being 100.

[0051] <Aging deterioration> Regarding the aging deterioration (aging deterioration property) of the container, an index with the value of Reference Example 1 being 100 was calculated from the data of M100 Aged described above. The results are shown in the lower part of Table 1 below. Note that this result indicates that the higher the numerical value, the more difficult it is for aging deterioration to progress (the lower the numerical value, the easier it is for aging deterioration to progress).

[0052]

Table 1

[0053] The detailed content of each component, etc. in Table 1 above is as follows. ·NR: Natural rubber (SIR20, manufactured by PT. PANTJA SURYA) ·IIR: Butyl rubber (EXXON Bromobutyl 2255, manufactured by ExxonMobil chemical company) · CB1: Carbon black (GPF, nitrogen adsorption specific surface area (N 2 SA): 35 m 2 / g, Nitron #GN: manufactured by Shin Nippon Carbon Co., Ltd.) · CB2: Carbon black (HAF, nitrogen adsorption specific surface area (N 2 SA): 93 m 2 / g, Seast KH: manufactured by Tokai Carbon Co., Ltd.) · Silica: Silica (ULTRASIL VN3GR, CTAB specific surface area 170 m 2 / g: manufactured by Evonik Corporation) · Zinc oxide: Silver Ridge R (manufactured by Toho Zinc Co., Ltd.) · Stearic acid: Bead Stearic acid Kiri (manufactured by Chiba Fatty Acids Co., Ltd.) · Resin (resin component): C5 resin (Homogenizing Agent H40MSF, manufactured by SHANDONG YANGGU HUATAI CHEMICAL Co., Ltd.) · Oil: Aroma oil (Diana Process NH-70S, manufactured by Idemitsu Kosan Co., Ltd.) · Sulfur: Sulfax 5 (manufactured by Tsuruimi Chemical Industry Co., Ltd.) · Vulcanization accelerator: Nocceler DM-PO (manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.)

[0054] From these results, in Examples 1 to 5 where the container is composed of a rubber component containing 35% by mass or less of NR and 65% by mass or more of IIR, and further contains 10 to 38 parts by mass of carbon black with respect to 100 parts by mass of this rubber component, both the sensing accuracy of the sensor function and the durability of the container were improved. Also, the aging deterioration property of the container was maintained or it was less likely to undergo aging deterioration. On the other hand, in Comparative Example 1 where the proportion of NR in the rubber component of the container was high and Comparative Example 2 where the carbon black content was low, aging deterioration of the container was more likely to progress in both cases. Also, in Comparative Example 3 where the carbon black content of the container was high, the sensing accuracy of the sensor function and the durability of the container were decreased.

Explanation of symbols

[0055] 100 Tire 1 Tread part 2 Sidewall part 3 Bead part 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 8 Belt cover layer 11 Tire circumferential groove 12 Inner surface of the tread part of the tire 20 Functional parts 21 Contact surface (piezoelectric element) 30 Container 31 Base part 32 Side wall 33 Accommodation part

Claims

1. A tire comprising a container in which functional components are housed on the inner surface of the tread portion of the tire, wherein the functional components have at least a contact surface that contacts the inner surface of the tire and a sensor function for detecting tire information, and the container is made of a rubber component containing 40% by mass or less of natural rubber (NR) and 60% by mass or more of butyl rubber (IIR), and further contains 10 to 38 parts by mass of carbon black with respect to 100 parts by mass of the rubber component.

2. The average value of the nitrogen adsorption specific surface area (N 2 SA) of the carbon black is less than 50 m 2 / g, and the tire according to claim 1.

3. The tire according to claim 1 or 2, wherein the container further contains 3 to 85 parts by mass of a white filler with respect to 100 parts by mass of the rubber component.

4. The tire according to claim 1 or 2, wherein the rubber component contains 80% by mass or more of the butyl rubber (IIR).

5. The tire according to claim 1 or 2, wherein the container is fixed to the inner surface of the tire.

6. The tire according to claim 5, wherein the container is fixed to the inner surface of the tire by an adhesive.

7. The tire according to claim 1 or 2, wherein the sensor function of the functional component is a sensor function using a piezoelectric element as a sensor element.

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