JP2021084512A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire which can secure the communication property of a transponder.SOLUTION: A transponder 20 which extends along a tire circumferential direction is embedded between a position P1 at 15 mm on the tire radial direction outer side from an upper end 5e of a bead core 5 and a position P2 at 5 mm on the tire radial direction inner side from a terminal 7e of a belt layer 7. An amount of silicon of a release agent detected by a fluorescent X-ray spectroscopy on a tire inner surface corresponding to at least the embedded position of the transponder 20 is equal to or less than 10.0 wt.%, or the thickness of the release agent detected by an electron microscope is equal to or less than 100 μm.SELECTED DRAWING: Figure 2

Description

The present invention relates to a pneumatic tire in which a transponder is embedded, and more particularly to a pneumatic tire that enables communication of the transponder to be ensured.

When vulcanizing a green tire using a bladder in a pneumatic tire, the bladder easily sticks to the inner surface of the green tire. Therefore, by applying a mold release agent to the inner surface of the green tire, the green tire I try to prevent sticking between the tire and the bladder. Generally, the release agent contains materials such as carbon, mica, and silicone, and among these materials, carbon has a characteristic of easily reflecting radio waves.

When a transponder is embedded inside such a pneumatic tire (see, for example, Patent Document 1), when communicating with the transponder using a reader / writer, radio waves are transmitted by a layered mold release agent formed on the inner surface of the tire. There is a problem that reflection occurs and the communication distance decreases due to the cancellation of radio waves.

Japanese Unexamined Patent Publication No. 7-137510

An object of the present invention is to provide a pneumatic tire capable of ensuring the communicability of a transponder.

In order to achieve the above object, the pneumatic tire of the present invention includes a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and these sidewall portions. A pair of bead portions arranged inside in the tire radial direction are provided, a bead filler is arranged on the outer periphery of the bead core of each bead portion, and at least one carcass layer is mounted between the pair of bead portions. In a pneumatic tire in which a plurality of belt layers are arranged on the outer peripheral side of the carcass layer in the tread portion, a position 15 mm outward in the tire radial direction from the upper end of the bead core and 5 mm inward in the tire radial direction from the terminal of the belt layer. A transponder extending along the tire circumferential direction is embedded between the tire and the position of the tire, and the amount of silicon of the release agent detected by the fluorescent X-ray analysis method is at least on the inner surface of the tire corresponding to the embedding location of the transponder. It is characterized in that it is 10.0% by weight or less.

Further, in the pneumatic tire of the present invention, a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and the inside of these sidewall portions in the tire radial direction. The bead filler is arranged on the outer periphery of the bead core of each bead portion, and at least one carcass layer is mounted between the pair of bead portions. In a pneumatic tire in which a plurality of belt layers are arranged on the outer peripheral side of the carcass layer, a position 15 mm outward in the tire radial direction from the upper end of the bead core and a position 5 mm inward in the tire radial direction from the terminal of the belt layer. A transponder extending along the tire circumferential direction is embedded between the tires, and the thickness of the release agent detected by an electron microscope is at least 100 μm or less on the inner surface of the tire corresponding to the embedding location of the transponder. To do.

The inventor of the present invention has found that it is effective to specify the amount or thickness of the release agent adhering to the inner surface of the tire in order to ensure the communicability of the transponder, and has reached the present invention. ..

In the present invention, a transponder extending along the tire circumferential direction is embedded between the position 15 mm outside the tire radial direction from the upper end of the bead core and the position 5 mm inside the tire radial direction from the end of the belt layer. , Metal interference is unlikely to occur, and the communicability of the transponder can be ensured. In particular, at least on the inner surface of the tire corresponding to the buried part of the transponder, the amount of silicon of the release agent detected by the fluorescent X-ray analysis method is 10.0% by weight or less, or the release detected by an electron microscope. Since the thickness of the mold is 100 μm or less, the amount of the mold release agent adhering to the inner surface of the tire is very small, and it is possible to suppress the cancellation of radio waves during communication caused by the mold release agent, and the communicability of the transponder. It contributes to the improvement of.

In the pneumatic tire of the present invention, the amount of silicon of the release agent is preferably 0.1% by weight to 10.0% by weight, or the thickness of the release agent is preferably 0.1 μm to 100 μm. For example, buffing the inner surface of the tire after vulcanization, or attaching a film to the inner surface of the green tire in advance, applying a mold release agent to the inner surface of the green tire with the film attached, and applying the film after vulcanization. By peeling off, the mold release agent on the inner surface of the tire can be completely removed, but in that case, there is a concern that the air retention of the tire may be deteriorated. On the other hand, the communicability of the transponder can be ensured without extremely deteriorating the air retention.

It is preferable that the center of the transponder is arranged at a distance of 10 mm or more in the tire circumferential direction from the splice portion of the tire component member. Thereby, the durability of the tire can be effectively improved.

It is preferable that the transponder is arranged so as to be in contact with the rubber layer between the carcass layer and the rubber layer arranged outside the carcass layer at the sidewall portion. As a result, the attenuation of radio waves during communication is suppressed, and the communicability of the transponder can be effectively improved.

The distance between the cross-sectional center of the transponder and the outer surface of the tire is preferably 2 mm or more. As a result, the durability of the tire can be effectively improved, and the traumatic resistance of the tire can be improved.

It is a pneumatic tire in which an inner liner layer is arranged on the inner surface of the tire along the carcass layer, and the transponder is preferably arranged between the carcass layer and the inner liner layer. When the transponder is placed outside the winding part of the carcass layer in the tire width direction, the transponder may be damaged due to the damage of the sidewall part, whereas the damage of the transponder due to the damage of the sidewall part is caused. Can be prevented.

The distance between the cross-sectional center of the transponder and the inner surface of the tire is preferably 1 mm or more. As a result, the durability of the tire can be effectively improved, and damage to the transponder due to damage to the inner liner layer during rim assembly can be prevented.

It is preferable that the transponder is arranged between the position 5 mm outside the tire radial direction from the upper end of the bead filler and the position 5 mm inside the tire radial direction from the end of the belt layer. As a result, the transponder is arranged in the flex zone where the rubber gauge is thin, but since the radio wave is less attenuated during the communication of the transponder in this region, the communication property of the transponder can be effectively improved.

The transponder is coated with a coating layer, and the relative permittivity of the coating layer is preferably 7 or less. As a result, the transponder is protected by the coating layer, the durability of the transponder can be improved, the radio wave transmission of the transponder can be ensured, and the communication property of the transponder can be sufficiently ensured.

The transponder is coated with a coating layer, and the thickness of the coating layer is preferably 0.5 mm to 3.0 mm. As a result, the communicability of the transponder can be sufficiently ensured without causing unevenness on the outer surface of the tire or the inner surface of the tire.

The transponder has an IC board for storing data and an antenna for transmitting and receiving data, and the antenna is preferably spiral. As a result, it is possible to follow the deformation of the tire during running, and it is possible to improve the durability of the transponder.

It is a meridian semi-cross-sectional view which shows the pneumatic tire which comprises the embodiment of this invention. FIG. 5 is a cross-sectional view taken along the meridian line schematically showing the pneumatic tire of FIG. FIG. 5 is a cross-sectional view taken along the equator line schematically showing the pneumatic tire of FIG. FIG. 5 is an enlarged cross-sectional view showing a transponder embedded in the pneumatic tire of FIG. 1. (A) and (b) are perspective views which show the transponder which can be embedded in the pneumatic tire which concerns on this invention. It is a meridian semi-cross-sectional view which shows the modification of the pneumatic tire which concerns on embodiment of this invention. FIG. 6 is an enlarged cross-sectional view showing a transponder embedded in the pneumatic tire of FIG. It is explanatory drawing which shows the tire radial position of a transponder in a test tire.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIGS. 1 to 4 show a pneumatic tire according to an embodiment of the present invention.

As shown in FIG. 1, the pneumatic tire of the present embodiment includes a tread portion 1 extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions 2 arranged on both sides of the tread portion 1, and these. It includes a pair of bead portions 3 arranged inside the sidewall portion 2 in the tire radial direction.

At least one layer (one layer in FIG. 1) of the carcass layer 4 formed by arranging a plurality of carcass cords in the radial direction is mounted between the pair of bead portions 3. As the carcass cord constituting the carcass layer 4, an organic fiber cord such as nylon or polyester is preferably used. An annular bead core 5 is embedded in each bead portion 3, and a bead filler 6 made of a rubber composition having a triangular cross section is arranged on the outer periphery of the bead core 5.

On the other hand, a plurality of layers (two layers in FIG. 1) of belt layers 7 are embedded on the outer peripheral side of the tire of the carcass layer 4 in the tread portion 1. The belt layer 7 includes a plurality of reinforcing cords that are inclined with respect to the tire circumferential direction, and the reinforcing cords are arranged so as to intersect each other between the layers. In the belt layer 7, the inclination angle of the reinforcing cord with respect to the tire circumferential direction is set in the range of, for example, 10 ° to 40 °. As the reinforcing cord of the belt layer 7, a steel cord is preferably used.

On the outer peripheral side of the tire of the belt layer 7, at least one layer (two layers in FIG. 1) in which reinforcing cords are arranged at an angle of, for example, 5 ° or less with respect to the tire peripheral direction for the purpose of improving high-speed durability. The belt cover layer 8 is arranged. In FIG. 1, the belt cover layer 8 located inside the tire radial direction constitutes a full cover covering the entire width of the belt layer 7, and the belt cover layer 8 located outside the tire radial direction covers only the end portion of the belt layer 7. It constitutes an edge cover layer. As the reinforcing cord of the belt cover layer 8, an organic fiber cord such as nylon or aramid is preferably used.

In the pneumatic tire, both terminals 4e of the carcass layer 4 are arranged so as to be folded back from the inside to the outside of each bead core 5 and wrap the bead core 5 and the bead filler 6. The carcass layer 4 is wound around the bead core 5 in each bead portion 3 and the main body portion 4A which is a portion extending from the tread portion 1 through each sidewall portion 2 to each bead portion 3, and is wound up on each sidewall portion 2 side. It includes a winding portion 4B which is a portion extending toward the direction.

Further, an inner liner layer 9 is arranged along the carcass layer 4 on the inner surface of the tire. A cap tread rubber layer 11 is arranged on the tread portion 1, a sidewall rubber layer 12 is arranged on the sidewall portion 2, and a rim cushion rubber layer 13 is arranged on the bead portion 3. The rubber layer 10 arranged on the outside of the carcass layer 4 in the sidewall portion 2 includes the sidewall rubber layer 12 and the rim cushion rubber layer 13.

Further, in the pneumatic tire, a position P1 15 mm outward in the tire radial direction from the upper end 5e (outer end in the tire radial direction) of the bead core 5 and a position P2 5 mm inward in the tire radial direction from the terminal 7e of the belt layer 7. A transponder 20 is buried between the tire and the tire. That is, the transponder 20 is arranged in the region S1 shown in FIG. Further, the transponder 20 extends along the tire circumferential direction. The transponder 20 may be arranged so as to be inclined in a range of −10 ° to 10 ° with respect to the tire circumferential direction.

In the embodiment of FIGS. 1 and 2, the terminal 4e of the winding portion 4B of the carcass layer 4 is arranged in the middle of the sidewall portion 2, but the terminal 4e of the winding portion 4B of the carcass layer 4 is shown. It may be arranged on the side of the bead core 5. In such a low tanup structure, the transponder 20 is arranged between the carcass layer 4 (more specifically, the bead filler 6) and the sidewall rubber layer 12 or the rim cushion rubber layer 13 while abutting against the rubber layer. You may have.

As the transponder 20, for example, an RFID (Radio Frequency Identification) tag can be used. As shown in FIGS. 5A and 5B, the transponder 20 has an IC substrate 21 for storing data and an antenna 22 for transmitting and receiving data in a non-contact manner. By using such a transponder 20, it is possible to write or read information about the tire in a timely manner and efficiently manage the tire. RFID is an automatic recognition technology that is composed of a reader / writer having an antenna and a controller, an IC board, and an ID tag having an antenna, and can communicate data wirelessly.

The overall shape of the transponder 20 is not particularly limited, and for example, a columnar or plate-shaped transponder can be used as shown in FIGS. 5A and 5B. In particular, when the columnar transponder 20 shown in FIG. 5A is used, it is preferable because it can follow the deformation of the tire in each direction. In this case, the transponder 20's antenna 22 protrudes from each of both ends of the IC substrate 21 and has a spiral shape. As a result, it is possible to follow the deformation of the tire during traveling, and it is possible to improve the durability of the transponder 20. Further, communication can be ensured by appropriately changing the length of the antenna 22.

Further, in the pneumatic tire, at least on the inner surface of the tire corresponding to the buried portion of the transponder 20, the amount of silicon of the release agent is 10.0% by weight or less. In the present invention, in defining the amount of the mold release agent on the inner surface of the tire, the amount of silicon, which is the main component of the general mold release agent, is used as an index. The amount of silicon can be detected by using a fluorescent X-ray analysis method. Generally, the fluorescent X-ray analysis method includes an FP method (fundamental parameter method) and a calibration curve method. In the present invention, the FP method is used. adopt. When measuring the amount of the release agent (silicon), the carcass layer and the inner liner layer are applied at a plurality of locations of the pneumatic tire (for example, four locations in the tire circumferential direction and three locations in the tire width direction, for a total of seven locations). Using the sheet sample (dimensions: width 70 mm, length 100 mm) obtained by peeling, a total of 5 measurement samples (dimensions: width 13 mm to 15 mm, 4 corners and 1 center) were added to each sheet sample. A length of 35 mm to 40 mm) is sampled, and the amount of the release agent is measured for each measurement sample using a fluorescent X-ray analyzer. Then, the amount of the release agent for each sheet sample is calculated by averaging the measured values of the five measurement samples for each of the sheet samples, and the calculated values are 10.0% by weight or less, respectively. In addition, fluorescent X-ray particles have an inherent energy proportional to the atomic number, and it is possible to identify an element by measuring this intrinsic energy. Specifically, the intrinsic energy of silicon is 1.74 ± 0.05 keV. The number of fluorescent X-ray particles (X-ray intensity) of the release agent (silicon) is in the range of 0.1 cps / μA to 1.5 cps / μA.

Alternatively, at least on the inner surface of the tire corresponding to the buried portion of the transponder 20, the thickness of the release agent is 100 μm or less. The thickness of this release agent can be detected using an electron microscope. When measuring the thickness of the release agent with an electron microscope, a sample obtained by cutting out the pneumatic tire along the tire width direction is used, and a plurality of points (for example, four points in the tire circumferential direction and the tire width) are used in the sample. Measure the thickness in three directions). Then, the thickness (average thickness) of the release agent is calculated by averaging the measured values measured at the plurality of locations.

As the release agent, it is preferable to use a release agent containing no carbon, but it is preferable to use a release agent having a carbon content of less than 5% by weight. In particular, the release agent contains an insulator composed of silicone, mica and talc, and it is preferable to use a release agent in which the amount of silicone constituting the insulator is 80% by weight or more. Examples of the silicone component include organopolysiloxanes, and examples thereof include dialkylpolysiloxane, alkylphenylpolysiloxane, alkylaralkylpolysiloxane, and 3,3,3-trifluoropropylmethylpolysiloxane. The dialkylpolysiloxane is, for example, dimethylpolysiloxane, diethylpolysiloxane, methylisopropylpolysiloxane, or methyldodecylpolysiloxane. The alkylphenyl polysiloxane is, for example, a methylphenyl polysiloxane, a dimethylsiloxane / methylphenylsiloxane copolymer, or a dimethylsiloxane / diphenylsiloxane copolymer. The alkylaralkyl polysiloxane is, for example, methyl (phenylethyl) polysiloxane or methyl (phenylpropyl) polysiloxane. These organopolysiloxanes may be used alone or in combination of two or more.

In the above-mentioned pneumatic tire, it extends along the tire circumferential direction between the position P1 15 mm outward in the tire radial direction from the upper end 5e of the bead core 5 and the position P2 5 mm inward in the tire radial direction from the terminal 7e of the belt layer 7. Since the existing transponder 20 is embedded, metal interference is unlikely to occur, and the communicability of the transponder 20 can be ensured. In particular, at least on the inner surface of the tire corresponding to the buried portion of the transponder 20, the amount of silicon of the release agent detected by the fluorescent X-ray analysis method is 10.0% by weight or less, or it is detected by an electron microscope. Since the thickness of the release agent is 100 μm or less, the amount of the release agent adhering to the inner surface of the tire is very small, and it is possible to suppress the cancellation of radio waves during communication caused by the release agent. It contributes to the improvement of communication.

Here, if the transponder 20 is arranged inside the tire radial direction from the position P1, metal interference with the rim flange occurs, and the communication property of the transponder 20 tends to deteriorate. Further, when the transponder 20 is arranged outside the position P2 in the tire radial direction, metal interference with the belt layer 7 occurs, and the communication property of the transponder 20 tends to deteriorate.

In the pneumatic tire, the amount of silicon of the release agent is preferably 0.1% by weight to 10.0% by weight, or the thickness of the release agent is preferably 0.1 μm to 100 μm. For example, buffing the inner surface of the tire after vulcanization, or attaching a film to the inner surface of the green tire in advance, applying a mold release agent to the inner surface of the green tire with the film attached, and applying the film after vulcanization. By peeling off, the mold release agent on the inner surface of the tire can be completely removed, but at that time, there is a concern that the air retention of the tire may be deteriorated. On the other hand, the communicability of the transponder 20 can be ensured without extremely deteriorating the air retention.

In the pneumatic tire, the transponder 20 is preferably arranged between the carcass layer 4 and the rubber layer 10 so as to be in contact with the rubber layer 10. That is, it is preferable that the transponder 20 is arranged between the carcass layer 4 and the sidewall rubber layer 12 or the rim cushion rubber layer 13 while being in contact with the rubber layer as an arrangement area in the tire width direction. When the transponder 20 is arranged in this way, the attenuation of radio waves during communication is suppressed, and the communicability of the transponder 20 can be effectively improved.

Further, the transponder 20 may be arranged between the position P3 5 mm outside the tire radial direction from the upper end 6e of the bead filler 6 and the position P2 5 mm inside the tire radial direction from the terminal 7e of the belt layer 7. .. That is, it is preferable that the transponder 20 is arranged in the region S2 shown in FIG. The area S2 is a flex zone having a thin rubber gauge, but when the transponder 20 is arranged in the area S2, the attenuation of radio waves during communication of the transponder 20 is reduced, and the communication property of the transponder 20 can be effectively improved. ..

As shown in FIG. 3, there are a plurality of splice portions on the tire circumference in which the ends of the tire constituent members are overlapped with each other. FIG. 3 shows the position Q of each splice portion in the tire circumferential direction. The center of the transponder 20 is preferably arranged at a distance of 10 mm or more in the tire circumferential direction from the splice portion of the tire component member. That is, it is preferable that the transponder 20 is arranged in the region S3 shown in FIG. Specifically, it is preferable that the IC substrate 21 constituting the transponder 20 is separated from the position Q by 10 mm or more in the tire circumferential direction. Further, it is more preferable that the entire transponder 20 including the antenna 22 is separated from the position Q in the tire circumferential direction by 10 mm or more, and the entire transponder 20 in the state of being covered with the covering rubber is in the tire circumferential direction from the position Q. Most preferably, they are separated by 10 mm or more. Further, as the tire constituent member arranged apart from the transponder 20, it is preferable that the inner liner layer 9, the carcass layer 4, the sidewall rubber layer 12 or the rim cushion rubber layer 13 can be arranged adjacent to the transponder 20. By arranging the transponder 20 away from the splice portion of the tire constituent member in this way, the durability of the tire can be effectively improved.

In the embodiment of FIG. 3, an example is shown in which the positions Q of the splice portions of the tire constituent members in the tire circumferential direction are arranged at equal intervals, but the present invention is not limited to this. The position Q in the tire circumferential direction can be set to an arbitrary position, and in any case, the transponder 20 is arranged so as to be separated from the splice portion of each tire component by 10 mm or more in the tire circumferential direction.

As shown in FIG. 4, the distance d1 between the cross-sectional center of the transponder 20 and the outer surface of the tire is preferably 2 mm or more. By separating the transponder 20 from the outer surface of the tire in this way, the durability of the tire can be effectively improved, and the traumatic resistance of the tire can be improved.

Further, the transponder 20 is preferably covered with a coating layer 23. The coating layer 23 covers the entire transponder 20 so as to sandwich both the front and back surfaces of the transponder 20. The coating layer 23 may be made of rubber having the same physical characteristics as the rubber constituting the sidewall rubber layer 12 or the rim cushion rubber layer 13, or may be made of rubber having different physical characteristics. Since the transponder 20 is protected by the coating layer 23 in this way, the durability of the transponder 20 can be improved.

In the pneumatic tire, the relative permittivity of the coating layer 23 is preferably 7 or less, and more preferably 2 to 5 in a state where the transponder 20 is covered with the coating layer 23. By appropriately setting the relative permittivity of the coating layer 23 in this way, it is possible to secure radio wave transmission when the transponder 20 radiates radio waves and effectively improve the communication property of the transponder 20. The relative permittivity of the rubber constituting the coating layer 23 is a relative permittivity of 860 MHz to 960 MHz at room temperature. Here, the room temperature conforms to the standard state of the JIS standard, and is 23 ± 2 ° C. and 60% ± 5% RH. The relative permittivity of the rubber is measured after being treated at 23 ° C. and 60% RH for 24 hours. The above-mentioned range of 860 MHz to 960 MHz corresponds to the current assigned frequency of RFID in the UHF band, but when the above-mentioned allotted frequency is changed, the relative permittivity of the allotted frequency range may be defined as described above.

Further, in a state where the transponder 20 is covered with the coating layer 23, the thickness t of the coating layer 23 is preferably 0.5 mm to 3.0 mm, more preferably 1.0 mm to 2.5 mm. Here, the thickness t of the coating layer 23 is the rubber thickness at the position including the transponder 20, and is, for example, on a straight line passing through the center of the transponder 20 and orthogonal to the outer surface of the tire as shown in FIG. It is the total rubber thickness of the thickness t1 and the thickness t2. By appropriately setting the thickness t of the coating layer 23 in this way, the communicability of the transponder 20 can be effectively improved without causing unevenness on the outer surface of the tire or the inner surface of the tire. Here, if the thickness t of the coating layer 23 is thinner than 0.5 mm, the effect of improving the communication property of the transponder 20 cannot be obtained, and conversely, if the thickness t of the coating layer 23 exceeds 3.0 mm, Unevenness is generated on the outer surface of the tire or the inner surface of the tire, which is not preferable. The cross-sectional shape of the covering layer 23 is not particularly limited, but for example, a triangular shape, a rectangular shape, a trapezoidal shape, or a spindle shape can be adopted. The coating layer 23 of FIG. 4 has a substantially spindle-shaped cross-sectional shape.

6 and 7 show a modified example of the pneumatic tire according to the embodiment of the present invention. In FIGS. 6 and 7, the same objects as those in FIGS. 1 to 4 are designated by the same reference numerals, and detailed description of the parts thereof will be omitted.

As shown in FIG. 6, a transponder 20 is embedded between the carcass layer 4 and the inner liner layer 9. When the transponder is arranged between the carcass layer and the sidewall rubber layer or the rim cushion rubber layer so as to be in contact with the rubber layer, the transponder may be damaged due to the damage of the sidewall portion. On the other hand, when the transponder 20 is embedded between the carcass layer 4 and the inner liner layer 9 as shown in FIG. 6, damage to the transponder 20 due to damage to the sidewall portion 2 can be prevented.

As shown in FIG. 7, the distance d2 between the cross-sectional center of the transponder 20 and the inner surface of the tire is preferably 1 mm or more. By separating the transponder 20 from the inner surface of the tire in this way, the durability of the tire can be effectively improved, and damage to the transponder 20 due to damage to the inner liner layer 9 during rim assembly can be prevented. be able to.

In the above-described embodiment, an example of a pneumatic tire having one carcass layer has been shown, but the tire is not particularly limited, and may have two carcass layers. Further, in the above-described embodiment, an example is shown in which the terminal 4e of the winding portion 4B of the carcass layer 4 is arranged in the middle of the sidewall portion 2 beyond the upper end 6e of the bead filler 6, but the present invention is limited to this. Instead, it can be placed at any height.

Next, the method for manufacturing the pneumatic tire of the present invention will be described. Before vulcanizing a green tire, the bladder is coated with a release agent (preferably by baking) to form a coating layer composed of the release agent on the outer surface of the bladder. The step of forming the coating layer on the outer surface of the bladder is carried out, for example, while storing the release agent under the conditions of 150 ° C. for 1 hour, 90 ° C. for 4 hours or room temperature for 8 hours after application. Further, the step of forming the coating layer on the outer surface of the bladder is carried out once or more and three times or less. The green tire is vulcanized using the bladder on which the coating layer is formed in this way. When vulcanized using a bladder provided with a coating layer made of a mold release agent in this way, the mold release agent is transferred to the inner surface of the vulcanized pneumatic tire. In the transfer layer made of this release agent, the release agent is not transferred to the entire surface of the inner surface of the tire and is scattered.

Instead of vulcanizing using a bladder provided with a coating layer made of a mold release agent as described above, vulcanization can also be performed using a core in the vulcanization step of a green tire. Alternatively, buffing the inner surface of the tire after vulcanization, or attaching a film to the inner surface of the green tire in advance, applying a mold release agent to the inner surface of the green tire with the film attached, and applying the film after vulcanization. By peeling off, the mold release agent on the inner surface of the tire can be completely removed.

By vulcanizing using a bladder provided with a coating layer made of a mold release agent as described above, or by vulcanizing using a core, at least on the inner surface of the tire corresponding to the buried portion of the transponder 20. The amount of silicon of the release agent detected by the fluorescent X-ray analysis method can be 10.0% by weight or less, or 100 μm or less. When the amount of the release agent adhering to the inner surface of the tire is very small as described above, it is possible to suppress the cancellation of radio waves during communication caused by the release agent, and it is possible to improve the communicability of the transponder 20.

With a tire size of 265 / 40ZR20, a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and these sidewall portions are arranged inside the tire radial direction. A pair of bead portions are provided, a bead filler is arranged on the outer periphery of the bead core of each bead portion, a carcass layer is mounted between the pair of bead portions, and a plurality of belt layers are mounted on the outer peripheral side of the carcass layer in the tread portion. In the pneumatic tire in which is arranged, a transponder extending along the tire circumferential direction is embedded, and the release agent (removal method and amount) and the position of the transponder (tire radial direction) are set as shown in Table 1. The tires of Examples 1 to 5 and Examples 1 to 6 were manufactured.

In Table 1, when the vulcanization method is "normal", vulcanization molding is performed using a normal bladder, and when the vulcanization method is "core", vulcanization molding is performed using a core. When the vulcanization method was "coating", vulcanization molding was performed using a bladder provided with a coating layer made of a mold release agent. Further, in Table 1, the amount of the release agent (silicon) adhering to the inner surface of the tire was determined by each test after the completion of the manufacturing process using an energy dispersive fluorescent X-ray analyzer (EDX-720 manufactured by Shimadzu Corporation). It is an average of the calculated values calculated based on the amount of the mold release agent (silicon) measured at four points in the tire circumferential direction and three points in the tire width direction of the tire. The measurement conditions are a voltage of 50 kV, a current of 100 μA, an integration time of 50 seconds, and a collimator of φ10 mm in a vacuum state. Further, in Table 1, the positions of the transponders (in the tire radial direction) correspond to the respective positions A to F shown in FIG.

For these test tires, tire evaluation (air retention) and transponder evaluation (communication) were carried out by the following test methods, and the results are also shown in Table 1.

Air retention (tire):
After assembling each test tire to the wheel of the standard rim and leaving it for 24 hours under the conditions of air pressure 270 kPa and temperature 21 ° C, the initial air pressure was set to 250 kPa and the air pressure was measured for 42 days, and the air on the 15th to 42nd days. The slope of the leak amount was calculated. The evaluation result is shown by an index with Comparative Example 2 as 100 using the reciprocal of the measured value. The larger the index value, the better the air retention.

Communication (transponder):
For each test tire, communication work with the transponder was carried out using a reader / writer. Specifically, the maximum distance that can be communicated with a reader / writer with an output of 250 mW and a carrier frequency of 860 MHz to 960 MHz was measured. The evaluation result is shown by an index with Comparative Example 2 as 100. The larger the index value, the better the communication.

As can be seen from Table 1, in Examples 1 to 6, the communicability of the transponder was improved. In Examples 3 to 6, a bladder provided with a coating layer made of a core or a mold release agent was used in the vulcanization step, so that the air retention of the tire was maintained.

On the other hand, in Comparative Example 1, since vulcanization molding was performed using a normal bladder, the communication property of the transponder deteriorated. In Comparative Example 3, the inner surface of the tire was washed under high pressure after normal vulcanization molding, but a large amount of the release agent remained on the inner surface of the tire, and the amount exceeded the amount specified in the present invention. Communication has deteriorated. In Comparative Example 4, since the position of the transponder in the tire radial direction was out of the range specified in the present invention, the communication property of the transponder deteriorated. In Comparative Example 5, since the amount of the mold release agent on the inner surface of the tire exceeded the amount specified in the present invention, the communication property of the transponder was not improved.

Next, a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a pair of bead portions arranged inside the tire radial direction of these sidewall portions. A bead filler is arranged on the outer periphery of the bead core of each bead portion, a carcass layer is mounted between the pair of bead portions, and a plurality of belt layers are arranged on the outer peripheral side of the carcass layer in the tread portion. In a pneumatic tire, a transponder extending along the tire circumferential direction is embedded, and the release agent (removal method and thickness) and the position of the transponder (tire radial direction) are set as shown in Table 2 from Comparative Example 6 to The tires of No. 10 and Examples 7 to 12 were manufactured.

In Table 2, the thickness [μm] of the release agent adhering to the inner surface of the tire is determined by using a scanning electron microscope (SEM-EDX) at four locations in the tire circumferential direction of each test tire after the manufacturing process is completed. The thickness of the release agent was measured at three points in the tire width direction, and these measured values were averaged. In Table 2, the positions of the transponders (in the tire radial direction) correspond to the respective positions A to F shown in FIG.

Tire evaluation (air retention) and transponder evaluation (communication) were carried out for these test tires, and the results are also shown in Table 2. In Table 2, the evaluation results of the air retention of the tire and the communication property of the transponder are shown by an index with Comparative Example 7 as 100.

As can be seen from Table 2, in Examples 7 to 12, the communicability of the transponder was improved. In Examples 9 to 12, a bladder provided with a coating layer made of a core or a mold release agent was used in the vulcanization step, so that the air retention of the tire was maintained.

On the other hand, in Comparative Example 6, since vulcanization molding was performed using a normal bladder, the communication property of the transponder deteriorated. In Comparative Example 8, the inner surface of the tire was washed under high pressure after normal vulcanization molding, but a large amount of the release agent remained on the inner surface of the tire, and the amount exceeded the amount specified in the present invention. Communication has deteriorated. In Comparative Example 9, since the position of the transponder in the tire radial direction was out of the range specified in the present invention, the communication property of the transponder deteriorated. In Comparative Example 10, since the thickness of the release agent on the inner surface of the tire exceeded the amount specified in the present invention, the communication property of the transponder was not improved.

Next, a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a pair of bead portions arranged inside the tire radial direction of these sidewall portions. A bead filler is arranged on the outer periphery of the bead core of each bead portion, a carcass layer is mounted between the pair of bead portions, and a plurality of belt layers are arranged on the outer peripheral side of the carcass layer in the tread portion. In a pneumatic tire, a transponder extending along the tire circumferential direction is embedded, and the position of the transponder (tire width direction, tire radial direction and tire circumferential direction), the distance between the transponder and the tire outer surface, and the transponder and the tire inner surface. The tires of Comparative Example 11 and Examples 13 to 31 in which the distance, the specific dielectric constant of the coating layer, the thickness of the coating layer, and the form of the transponder were set as shown in Tables 3 and 4 were produced.

Here, the tires of Comparative Examples 11 and 13 to 31 were vulcanized using a bladder provided with a coating layer made of a release agent, and the amount of the release agent (silicon) adhering to the inner surface of the tire was 0. .1% by weight.

In Tables 3 and 4, when the transponder position (tire width direction) is "W", the transponder is arranged between the bead filler and the carcass layer, and the transponder position (tire width direction) is "X". In the case of, the transponder is arranged between the carcass layer and the inner liner layer, and when the transponder position (in the tire width direction) is "Y", the transponder is placed between the carcass layer and the sidewall rubber layer. When the position of the transponder (in the tire width direction) is "Z", it indicates that the transponder is placed in contact with the rim cushion rubber layer between the carcass layer and the rim cushion rubber layer. .. Further, in Tables 3 and 4, the positions of the transponders (in the tire radial direction) correspond to the respective positions A to F shown in FIG. Further, in Tables 3 and 4, the position of the transponder (tire circumferential direction) indicates the distance [mm] measured in the tire circumferential direction from the center of the transponder to the splice portion of the tire constituent member.

For these test tires, tire evaluation (durability, trauma resistance and appearance) and transponder evaluation (communication, durability, trauma resistance and damage resistance) were carried out by the following test methods, and the results are shown in Table 3. And are also shown in Table 4. The evaluation result of the communication property of the transponder is shown by an index with Example 13 as 100.

Durability (tires and transponders):
After assembling each test tire to the wheel of the standard rim and conducting a running test with a drum tester under the conditions of an air pressure of 120 kPa, 102% of the maximum load, and a running speed of 81 km, running when a tire failure occurs. The distance was measured. The evaluation results are indicated by "◎ (excellent)" when the mileage reaches 6480 km, "○ (good)" when the mileage is 4050 km or more and less than 6480 km, and when the mileage is 3240 km or more and less than 4050 km. Is indicated by "Δ (possible)", and the case where the mileage is less than 3240 km is indicated by four stages of "x (impossible)". Further, after the running was completed, the outer surface of each test tire was visually inspected to confirm whether or not the tire failure originated from the transponder. The evaluation result showed the presence or absence of the failure.

Trauma resistance (tire):
Each test tire was attached to a standard rim wheel and mounted on a test vehicle, and a running test was conducted in which the tire was run while being in contact with a curb having a height of 100 mm under the conditions of an air pressure of 230 kPa and a running speed of 20 km / h. After running, it was visually confirmed whether or not the outer surface of the tire was damaged. The evaluation results showed the presence or absence of damage to the outer surface of the tire.

Appearance (tire):
For each test tire, the outer surface of the tire corresponding to the location of the transponder was visually confirmed. As for the evaluation result, the case where there was no unevenness due to the arrangement of the transponder on the outer surface of the tire was shown as "good", and the case where there was unevenness was shown as "poor".

Trauma resistance (transponder):
Each test tire was assembled to a standard rim wheel, mounted on a test vehicle, and a running test was conducted in which the tire rides on a curb with a height of 100 mm under the conditions of an air pressure of 230 kPa and a running speed of 20 km / h. After running, it was confirmed that the outer surface of the tire corresponding to the location of the transponder was damaged. The evaluation results showed the presence or absence of damage to the outer surface of the tire due to the placement of the transponder.

Damage resistance when assembling the rim (transponder):
For each test tire, the inner surface of the tire corresponding to the location of the transponder was visually inspected when the rim was replaced. The evaluation results showed the presence or absence of damage to the transponder due to damage to the inner liner.

As can be seen from Tables 3 and 4, in Examples 14 to 31, various improvement effects were confirmed in the tire evaluation and the transponder evaluation. On the other hand, in Comparative Example 11, since the position of the transponder in the tire radial direction was out of the range specified in the present invention, the communication property of the transponder deteriorated.

1 Tread part 2 sidewall part 3 bead part 4 carcass layer 4A main body part 4B winding part 5 bead core 6 bead filler 7 belt layer 9 inner liner layer 20 transponder CL tire center line P1 to P3 position

Claims (13)

A tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a pair of bead portions arranged inside the tire radial direction of these sidewall portions. A bead filler is arranged on the outer periphery of the bead core of each bead portion, at least one carcass layer is mounted between the pair of bead portions, and a plurality of layers of belts are mounted on the outer peripheral side of the carcass layer in the tread portion. In pneumatic tires with layers
A transponder extending along the tire circumferential direction is embedded between a position 15 mm outward in the tire radial direction from the upper end of the bead core and a position 5 mm inward in the tire radial direction from the end of the belt layer, and at least the transponder of the transponder. A pneumatic tire characterized in that the amount of silicon of the release agent detected by the fluorescent X-ray analysis method on the inner surface of the tire corresponding to the buried portion is 10.0% by weight or less. A tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a pair of bead portions arranged inside the tire radial direction of these sidewall portions. A bead filler is arranged on the outer periphery of the bead core of each bead portion, at least one carcass layer is mounted between the pair of bead portions, and a plurality of layers of belts are mounted on the outer peripheral side of the carcass layer in the tread portion. In pneumatic tires with layers
A transponder extending along the tire circumferential direction is embedded between a position 15 mm outward in the tire radial direction from the upper end of the bead core and a position 5 mm inward in the tire radial direction from the end of the belt layer, and at least of the transponder. A pneumatic tire characterized in that the thickness of the release agent detected by an electron microscope on the inner surface of the tire corresponding to the buried portion is 100 μm or less. The pneumatic tire according to claim 1, wherein the amount of silicon in the release agent is 0.1% by weight to 10.0% by weight. The pneumatic tire according to claim 2, wherein the release agent has a thickness of 0.1 μm to 100 μm. The pneumatic tire according to any one of claims 1 to 4, wherein the center of the transponder is arranged at a distance of 10 mm or more in the tire circumferential direction from the splice portion of the tire component member. The transponder according to claim 1 to 5, wherein the transponder is arranged so as to abut the rubber layer between the carcass layer and the rubber layer arranged outside the carcass layer at the sidewall portion. Pneumatic tires listed in either. The pneumatic tire according to claim 6, wherein the distance between the cross-sectional center of the transponder and the outer surface of the tire is 2 mm or more. A pneumatic tire in which an inner liner layer is arranged on the inner surface of the tire along the carcass layer, wherein the transponder is arranged between the carcass layer and the inner liner layer. The pneumatic tire according to any one of 1 to 5. The pneumatic tire according to claim 8, wherein the distance between the cross-sectional center of the transponder and the inner surface of the tire is 1 mm or more. Claims 1 to 9 are characterized in that the transponder is arranged between a position 5 mm outward in the tire radial direction from the upper end of the bead filler and a position 5 mm inward in the tire radial direction from the end of the belt layer. Pneumatic tires listed in any of. The pneumatic tire according to any one of claims 1 to 10, wherein the transponder is coated with a coating layer, and the relative permittivity of the coating layer is 7 or less. The pneumatic tire according to any one of claims 1 to 11, wherein the transponder is coated with a coating layer, and the thickness of the coating layer is 0.5 mm to 3.0 mm. The pneumatic tire according to any one of claims 1 to 12, wherein the transponder has an IC substrate for storing data and an antenna for transmitting and receiving data, and the antenna has a spiral shape.

Images