JP6786867B2 - Tire deterioration judgment device and pneumatic tire equipped with it - Google Patents

Description

The present invention relates to a tire deterioration determination device in which a determination rubber layer used for a deterioration degree determination test is mounted on the inner surface of the tire and a pneumatic tire provided with the determination rubber layer. The present invention relates to a tire deterioration determination device that can be easily peeled off and a pneumatic tire equipped with the device.

In recent years, from the viewpoint of effective use of resources and energy saving, rehabilitated tires obtained by regenerating the pneumatic tire after the tread portion of the pneumatic tire has become unusable due to wear have become widespread. In particular, rehabilitated tires are widely used for heavy-duty pneumatic tires used for trucks and buses.

When rehabilitating a used pneumatic tire, a base tire in which the tread rubber is ground is produced, and the base tire is coated with new tread rubber. In performing such rehabilitation work, in order to confirm the residual durability of the base tire, the presence or absence of internal separation is confirmed by a shearography inspection, and the presence or absence of trauma is confirmed by a visual inspection. ing. However, such an inspection cannot sufficiently evaluate the degree of deterioration of the rubber composition constituting the pneumatic tire.

On the other hand, a tire deterioration determining tool having a core rubber made of a sulfur-crosslinkable diene rubber composition coated with a cover rubber having an oxygen permeation coefficient equal to or higher than that of the inner liner layer of the tire is applied to the inner surface of the tire. It has been proposed to install the tire and determine the degree of deterioration of the pneumatic tire based on the result of the bending test of the tire deterioration determining tool (see, for example, Patent Document 1). In this case, the tire deterioration determining tool is previously adhered to the inner surface of the tire and is peeled off at the time of determining the tire deterioration.

However, when such a tire deterioration determining tool is firmly adhered to the inner surface of the tire with an adhesive, there is a problem that it is difficult to remove the tire deterioration determining tool from the inner surface of the tire. Further, if a large distortion occurs in the tire deterioration determining tool during the peeling operation, it becomes a factor that the determination accuracy when determining the degree of deterioration of the pneumatic tire by using the tire deterioration determining tool is lowered.

Japanese Unexamined Patent Publication No. 2006-327469

An object of the present invention is to make it possible to easily peel off the determination rubber layer from the inner surface of the tire in constructing a tire deterioration determination device in which the determination rubber layer used for the determination test of the degree of deterioration is mounted on the inner surface of the tire. It is an object of the present invention to provide a tire deterioration determination device and a pneumatic tire equipped with the device.

The tire deterioration determination device of the present invention for achieving the above object is composed of a determination rubber layer made of a rubber composition and an adhesive layer laminated on the determination rubber layer, and the determination rubber layer is the adhesive layer. In a tire deterioration determination device that is detachably mounted on the inner surface of the tire via
A non-adhesive region that does not come into direct contact with the adhesive layer exists on the laminated surface on which the adhesive layer of the determination rubber layer is laminated, and the area ratio of the non-adhesive region on the laminated surface is in the range of 10% to 90%. it is characterized in that.

Further, the pneumatic tire of the present invention for achieving the above object includes a tire deterioration determination device composed of a determination rubber layer made of a rubber composition and an adhesive layer laminated on the determination rubber layer. In a pneumatic tire in which the determination rubber layer is detachably attached to the inner surface of the tire via the adhesive layer .
A non-adhesive region that does not come into direct contact with the adhesive layer exists on the laminated surface on which the adhesive layer of the determination rubber layer is laminated, and the area ratio of the non-adhesive region on the laminated surface is in the range of 10% to 90%. it is characterized in that.

In the present invention, a tire deterioration determination device is configured from a determination rubber layer made of a rubber composition and an adhesive layer laminated on the determination rubber layer, and the determination rubber layer can be removed from the inner surface of the tire by the adhesive layer. Since it is mounted in the state, the judgment rubber layer can be easily peeled off from the inner surface of the tire when the tire deterioration is judged. In addition, since the judgment rubber layer is peeled off without difficulty, the distortion given to the judgment rubber layer in the peeling work is suppressed, and the judgment accuracy when judging the degree of deterioration of the pneumatic tire by using the judgment rubber layer is improved. It is also possible to do.

In the present invention, the average peeling force when removing the determination rubber layer from the inner surface of the tire is preferably 2.0 N / inch to 100 N / inch. As a result, while the determination rubber layer is firmly held on the inner surface of the tire when the tire is running, the determination rubber layer can be easily peeled off from the inner surface of the tire when the tire deterioration is determined.

The thickness of the adhesive layer is preferably 0.01 mm to 3.0 mm. By ensuring a sufficient thickness of the adhesive layer, it is possible to prevent the determination rubber layer from peeling off from the inner surface of the tire due to the influence of strain generated on the inner surface of the tire during running of the tire. Further, by defining the upper limit of the thickness of the adhesive layer, it is possible to suppress the mass imbalance on the tire circumference caused by the adhesive layer.

Judgment A non-adhesive region that does not come into direct contact with the adhesive layer exists on the laminated surface on which the adhesive layer of the rubber layer is laminated, and the area ratio of the non-adhesive region on the laminated surface is in the range of 10% to 90%. preferable. By partially providing a non-adhesive region that does not come into direct contact with the adhesive layer on the laminated surface on which the adhesive layer of the determination rubber layer is laminated in this way, the determination rubber layer is sufficiently maintained while maintaining the adhesiveness based on the adhesive layer. Can be easily peeled off from the inner surface of the tire.

At least a part of the non-adhesive region is preferably located at the end of the determination rubber layer. In this case, when the determination rubber layer is peeled off, the end portion of the determination rubber layer can be easily grasped, so that the peeling operation can be easily performed.

It is preferable that the end portion of the determination rubber layer on which the non-adhesive region is arranged has a contour shape different from that of the end portion on the opposite side thereof. In this case, the end portion on which the non-adhesive region of the determination rubber layer is arranged can be identified based on the contour shape, and the determination rubber layer can be easily peeled off by grasping the end portion.

Alternatively, it is preferable that the end portion of the determination rubber layer on which the non-adhesive region is arranged has a display portion colored in a color different from that of the determination rubber layer. In this case, the end portion on which the non-adhesive region of the determination rubber layer is arranged can be identified based on the display portion, and the determination rubber layer can be easily peeled off by grasping the end portion.

In the present invention, the average peeling force is measured according to the measuring method of "90 ° peeling adhesive force" described in JIS-Z0237 "Test method for adhesive tape / adhesive sheet". This average peeling force is measured by pulling the end portion of the determination rubber layer while grasping the end portion.

It is a meridian cross-sectional view which shows the pneumatic tire for heavy load which concerns on embodiment of this invention. It is a perspective view which shows the basic structure of the tire deterioration determination apparatus which concerns on this invention. It is a side view which shows the basic structure of the tire deterioration determination apparatus which concerns on this invention. It is a side view which shows the state which started to peel off the determination rubber layer in the tire deterioration determination apparatus of FIG. It is a side view which shows the modification of the tire deterioration determination apparatus which concerns on this invention. (A) to (i) are plan views showing other modified examples of the tire deterioration determination device according to the present invention, respectively. It is a side view which shows the further modification of the tire deterioration determination apparatus which concerns on this invention. (A) to (b) are plan views which show still another modification of the tire deterioration determination apparatus which concerns on this invention. (A) to (c) are plan views which show still another modification of the tire deterioration determination apparatus which concerns on this invention. It is a side view which shows the further modification of the tire deterioration determination apparatus which concerns on this invention. (A) to (b) are plan views which show still another modification of the tire deterioration determination apparatus which concerns on this invention. It is a side view which shows the further modification of the tire deterioration determination apparatus which concerns on this invention. It is a side view which shows the further modification of the tire deterioration determination apparatus which concerns on this invention. It is a side view which shows the further modification of the tire deterioration determination apparatus which concerns on this invention.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a pneumatic tire for a heavy load according to an embodiment of the present invention, and FIGS. 2 to 4 show a tire deterioration determination device according to the present invention.

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

A carcass layer 4 is mounted between the pair of bead portions 3 and 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and is folded back from the inside to the outside of the tire around the bead core 5 arranged in each bead portion 3. 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 belt layers 7 are embedded 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 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 60 °. A steel cord is preferably used as the reinforcing cord of the belt layer 7.

In the pneumatic tire, as shown in FIGS. 1 to 3, a sheet-shaped determination rubber layer 11 is detachably attached to the tire inner surface S facing the tire air chamber via a sheet-shaped adhesive layer 12. ing. That is, the adhesive layer 12 holds the determination rubber layer 11 in a removable state based on its adhesiveness. The determination rubber layer 11 and the adhesive layer 12 constitute the tire deterioration determination device 10. It is desirable that the tire deterioration determination device 10 is arranged in the tread portion 1 or the bead portion 3 in which the deformation during running is relatively small. The tire deterioration determination device 10 may be mounted on the inner surface S of the tire before or after vulcanization of the pneumatic tire, and only the adhesive layer 11 may be mounted before vulcanization. Normally, the tire deterioration determination device 10 including the determination rubber layer 11 and the adhesive layer 12 is attached to the tire inner surface S after vulcanization.

As the rubber composition constituting the determination rubber layer 11, for example, a sulfur-crosslinkable diene-based rubber composition can be used. Examples of the diene rubber include natural rubber (NR), isoprene rubber (IR), epoxidized natural rubber, styrene butadiene rubber (SBR), butadiene rubber (BR), nitrile rubber (NBR), hydride NBR, hydride SBR, etc. Can be mentioned. However, the rubber used for the determination rubber layer 11 is not limited to the above-mentioned diene-based rubber, and the rubber includes sulfur, a vulcanization accelerator, an antiaging agent, a filler such as carbon black, and softening of oil and the like. Agents, resins, metal salts such as wax and cobalt salts, and additives such as stearic acid and zinc oxide can be appropriately blended. In particular, in determining the oxidative deterioration of a tire, a natural rubber-based rubber composition that easily causes oxidative deterioration is preferable, and one containing sulfur and further a metal salt is preferable.

As the adhesive layer 12, for example, a double-sided tape in which an adhesive is applied to both sides of the base material or a sheet made of the adhesive can be used. As the adhesive, it is particularly preferable to use an acrylic adhesive. Acrylic adhesives are suitable adhesives because their adhesive strength does not decrease so much even at high temperatures (for example, about 100 ° C.).

In the pneumatic tire described above, the tire deterioration determination device 10 is composed of the determination rubber layer 11 made of the rubber composition and the adhesive layer 12 laminated on the determination rubber layer 11, and the determination rubber layer 11 is the adhesive layer 12. As shown in FIG. 4, the determination rubber layer 11 can be easily removed from the tire inner surface S at the time of tire deterioration determination by pulling the end portion of the determination rubber layer 11 because the tire inner surface S is detachably mounted. Can be peeled off. Further, since the determination rubber layer 11 is peeled off without difficulty, it is possible to suppress the strain given to the determination rubber layer 11 in the peeling operation. As a result, there is also an advantage that the determination accuracy when determining the degree of deterioration of the pneumatic tire by using the determination rubber layer 11 can be improved.

In the above pneumatic tire, the average peeling force when removing the determination rubber layer 11 from the tire inner surface S is 2.0 N / inch to 100 N / inch, more preferably 10 N / inch to 50 N / inch, and further preferably 20 N. It is preferable that it is / inch to 40 N / inch. As a result, the determination rubber layer 11 is firmly held on the tire inner surface S when the tire is running, while the determination rubber layer 11 can be easily peeled off from the tire inner surface S when the tire deterioration is determined. If the average peeling force of the determination rubber layer 11 is less than 2.0 N / inch, the determination rubber layer 11 may separate from the tire inner surface S when the tire is running, and conversely, if it exceeds 100 N / inch, the determination rubber layer It becomes difficult to peel off 11. The interface when the determination rubber layer 11 is peeled off may be between the tire inner surface S and the adhesive layer 12, or between the adhesive layer 12 and the determination rubber layer 11. Alternatively, the adhesive layer 12 may be broken. The most preferable form is that peeling occurs at the interface between the adhesive layer 12 and the determination rubber layer 11. Therefore, it is desirable to adopt a structure in which the peeling force between the tire inner surface S and the adhesive layer 12 is larger than the peeling force between the adhesive layer 12 and the determination rubber layer 11.

In the pneumatic tire, the thickness t (see FIG. 3) of the adhesive layer 12 is 0.01 mm to 3.0 mm, more preferably 0.03 mm to 2.0 mm, still more preferably 0.03 mm to 1.0 mm. It is good to be. If the thickness t of the adhesive layer 12 is less than 0.01 mm, the determination rubber layer 11 may be peeled off from the tire inner surface S due to the influence of strain generated on the tire inner surface S during tire running, and conversely, 3.0 mm. If it exceeds, the mass balance on the tire circumference due to the adhesive layer 12 will deteriorate.

5 and 6 (a) to 6 (i) show modifications of the tire deterioration determination device according to the present invention, respectively. In FIG. 5, the laminated surface X on which the adhesive layer 12 of the determination rubber layer 11 is laminated has a non-adhesive region X1 that does not directly contact the adhesive layer 12 and an adhesive region X2 that directly contacts the adhesive layer 12. In a plan view, as shown in FIGS. 6A to 6I, the area of the adhesive region X2 (hatched portion) is smaller than the area of the laminated surface X of the determination rubber layer 11. As a result, the ratio of the area of the non-adhesive region X1 to the area of the laminated surface X is in the range of 10% to 90%, more preferably in the range of 30% to 70%. By partially providing the non-adhesive region X1 that does not come into direct contact with the adhesive layer 12 on the laminated surface X on which the adhesive layer 12 of the determination rubber layer 11 is laminated in this way, the adhesiveness based on the adhesive layer 12 is sufficiently maintained. At the same time, the determination rubber layer 11 can be easily peeled off from the tire inner surface S. Here, if the area ratio of the non-adhesive region X1 to the laminated surface X is less than 10%, the effect of improving the ease of peeling of the determination rubber layer 11 decreases, and conversely, if it exceeds 90%, the tire is running. The determination rubber layer 11 may be peeled off from the tire inner surface S due to the influence of the strain generated on the tire inner surface S.

In FIG. 6A, the non-adhesive region X1 is arranged so as to extend in the longitudinal direction of the determination rubber layer 11 at both ends in the width direction of the determination rubber layer 11. In FIG. 6B, the non-adhesive region X1 is arranged so as to extend in the width direction of the determination rubber layer 11 at both ends in the longitudinal direction of the determination rubber layer 11. In FIG. 6C, the non-adhesive region X1 is arranged along the peripheral edge of the laminated surface X of the determination rubber layer 11. In FIG. 6D, the non-adhesive region X1 is arranged at the center of the laminated surface X of the determination rubber layer 11. In FIG. 6E, the non-adhesive region X1 is arranged so as to extend in the width direction of the determination rubber layer 11 at the central portion in the longitudinal direction of the determination rubber layer 11. In FIG. 6F, the non-adhesive region X1 is arranged so as to extend in the longitudinal direction of the determination rubber layer 11 at the central portion in the width direction of the determination rubber layer 11. In FIG. 6 (g), the non-adhesive region X1 extends while bending from one diagonal portion of the laminated surface X of the determination rubber layer 11 toward the other diagonal portion. In FIG. 6H, the non-adhesive region X1 is arranged at a portion of the determination rubber layer 11 excluding the four corners of the laminated surface X. In FIG. 6 (i), a plurality of adhesive regions X2 are arranged so as to be scattered on the laminated surface X of the determination rubber layer 11, and the portions other than the adhesive regions X2 are non-adhesive regions X1.

7 and 8 (a) to 8 (b) show still other modifications of the tire deterioration determination device according to the present invention, respectively. As shown in FIG. 7, the non-adhesive region X1 is arranged at the end of the determination rubber layer 11. In FIG. 8A, the non-adhesive region X1 is arranged only at one corner of the laminated surface X of the determination rubber layer 11. On the other hand, in FIG. 8B, the non-adhesive region X1 is arranged only at one end of the determination rubber layer 11 in the longitudinal direction. When at least a part of the non-adhesive region X1 is located at the end of the determination rubber layer 11 in this way, the end of the determination rubber layer 11 can be easily grasped when the determination rubber layer 11 is peeled off. Can be easily performed.

9 (a) to 9 (c) show still other modifications of the tire deterioration determination device according to the present invention, respectively. In FIGS. 9A to 9C, the end portion 11A in which the non-adhesive region X1 of the determination rubber layer 11 is arranged has a contour shape different from that of the end portion 11B on the opposite side thereof. That is, in FIG. 9A, both sides of the end portion 11A of the determination rubber layer 11 in the width direction are notched small. In FIG. 9B, both sides of the end portion 11A of the determination rubber layer 11 in the width direction are largely notched. In FIG. 9C, the end portion 11A of the determination rubber layer 11 is formed in an arrow shape. When the end portion 11A on which the non-adhesive region X1 of the determination rubber layer 11 is arranged is given a contour shape different from that of the end portion 11B on the opposite side, the non-adhesive region X1 of the determination rubber layer 11 is arranged. The end portion 11A can be identified based on its contour shape, and the determination rubber layer 11 can be easily peeled off by grasping the end portion 11A.

FIG. 10 shows still another modification of the tire deterioration determination device according to the present invention. In FIG. 10, the end portion 11A in which the non-adhesive region X1 of the determination rubber layer 11 is arranged has a contour shape different from that of the end portion 11B on the opposite side thereof. More specifically, in the determination rubber layer 11, the end portion 11A has a step and is locally thickened. In order to make the contour shape of the end portion 11A on which the non-adhesive region X1 of the determination rubber layer 11 is arranged different from the contour shape of the end portion 11B on the opposite side in this way, not only the contour shape in the plan view but also the cross-sectional view It is also possible to make the contour shape different.

11 (a) to 11 (b) show still other modifications of the tire deterioration determination device according to the present invention, respectively. In FIGS. 11A to 11B, the end portion 11A in which the non-adhesive region X1 of the determination rubber layer 11 is arranged has a display portion 13 (hatched portion) colored in a color different from that of the determination rubber layer 11. ing. More specifically, in FIG. 11A, a circular display portion 13 is arranged at the end portion 11A of the determination rubber layer 11. In FIG. 11B, a band-shaped display portion 13 is arranged at the end portion 11A of the determination rubber layer 11. When the display unit 13 colored in a color different from that of the determination rubber layer 11 is provided on the end portion 11A where the non-adhesive region X1 of the determination rubber layer 11 is arranged in this way, the non-adhesive region X1 of the determination rubber layer 11 becomes The arranged end portion 11A can be identified based on the display portion 13, and the determination rubber layer 11 can be easily peeled off by grasping the end portion 11A. The difference in color can depend on any of hue, lightness, and saturation.

FIG. 12 shows still another modification of the tire deterioration determination device according to the present invention. In FIG. 12, the tire deterioration determination device 10 is composed of a determination rubber layer 11 and an adhesive layer 12, and the adhesive layer 12 is located on the adhesive layer 121 located on the tire inner surface S side and on the determination rubber layer 11 side. It has a laminated structure including an adhesive layer 122. The adhesive layer 121 on the inner surface S side of the tire has a stronger adhesive force than the adhesive layer 122 on the determination rubber layer 11. As a result, the peeling force between the tire inner surface S and the adhesive layer 12 (adhesive layer 121) is larger than the peeling force between the adhesive layer 12 (adhesive layer 122) and the determination rubber layer 11. It has become. In this case, when the determination rubber layer 11 is peeled off, the interface between the adhesive layer 12 and the determination rubber layer 11 is preferentially peeled off, and the determination rubber layer 11 can be collected in a good state.

FIG. 13 shows still another modification of the tire deterioration determination device according to the present invention. In FIG. 13, the tire deterioration determination device 10 is composed of the determination rubber layer 11 and the adhesive layer 12, and the adhesive layer 12 has a plurality of recesses 14 at the interface with the determination rubber layer 11. Due to the presence of these recesses 14, a non-adhesive region X1 that does not come into direct contact with the adhesive layer 12 is formed on the laminated surface X on which the adhesive layer 12 of the determination rubber layer 11 is laminated. As a result, the structure is such that the peeling force between the tire inner surface S and the adhesive layer 12 is larger than the peeling force between the adhesive layer 12 and the determination rubber layer 11. In this case, when the determination rubber layer 11 is peeled off, the interface between the adhesive layer 12 and the determination rubber layer 11 is preferentially peeled off, and the determination rubber layer 11 can be collected in a good state.

FIG. 14 shows still another modification of the tire deterioration determination device according to the present invention. In FIG. 14, the tire deterioration determination device 10 is composed of a determination rubber layer 11 and an adhesive layer 12, and a plurality of release materials 15 are arranged at an interval between the determination rubber layer 11 and the adhesive layer 12. ing. Due to the presence of the release material 15, a non-adhesive region X1 that does not come into direct contact with the adhesive layer 12 is formed on the laminated surface X on which the adhesive layer 12 of the determination rubber layer 11 is laminated. As a result, the structure is such that the peeling force between the tire inner surface S and the adhesive layer 12 is larger than the peeling force between the adhesive layer 12 and the determination rubber layer 11. In this case, when the determination rubber layer 11 is peeled off, the interface between the adhesive layer 12 and the determination rubber layer 11 is preferentially peeled off, and the determination rubber layer 11 can be collected in a good state.

In the tire deterioration determination device shown in FIGS. 13 and 14, the arrangement pattern depicted in FIGS. 6 (a) to 6 (i) can be adopted as the arrangement pattern of the non-adhesive region X1 of the determination rubber layer 11. .. At that time, it is desirable to set the ratio of the area of the non-adhesive region X1 to the area of the laminated surface X of the determination rubber layer 11 in the range of 10% to 90%.

Hereinafter, a tire deterioration determination method using the tire deterioration determination device 10 described above will be briefly described. First, in a pneumatic tire, the determination rubber layer 11 of the tire deterioration determination device 10 is attached in a state of being removable from the tire inner surface S by the adhesive layer 12. The tire deterioration determination device 10 may be installed immediately after the production of the pneumatic tire, or may be installed at the start of use of the pneumatic tire. The determination rubber layer 11 of the tire deterioration determination device 10 has the physical characteristics at the time of a new product grasped in advance. Next, the determination rubber layer 11 mounted on the inner surface S of the tire is removed at an arbitrary time after the start of using the tire. For example, the determination rubber layer 11 is removed from the inner surface S of the tire when an arbitrary mileage is reached in the process of using the tire, when the rehabilitation work is performed, or when the tire is discarded. Then, the physical characteristics of the determination rubber layer 11 are measured, the amount of change in the physical characteristics from the time of new product is obtained using the measured value, and the degree of deterioration of the pneumatic tire is determined based on the amount of change.

Examples of the physical characteristics include weight (specific gravity), oxygen adsorption amount, electric resistance, hardness, breaking characteristics, viscous elasticity characteristics, and the like. When the determination rubber layer 11 deteriorates due to oxidation, the weight (specific gravity), the amount of oxygen adsorbed, the electric resistance, the hardness, the breaking characteristics, and the viscous characteristics change with the deterioration. The degree of deterioration of the pneumatic tire can be accurately determined based on the above. It is also possible to chemically analyze the determination rubber layer 11 and use the analysis result as an index of the degree of deterioration.

A tire deterioration determination device composed of a determination rubber layer made of a rubber composition and an adhesive layer laminated on the determination rubber layer is prepared, and each of these tire deterioration determination devices is a pneumatic tire having a tire size of 11R22.5. It was attached to the inner surface of (Examples 1 to 7). The tire deterioration determination device was mounted on the inner surface of the tire at the position of the equator of the tire.

In Examples 1 to 7, a non-adhesive region that does not come into direct contact with the adhesive layer is formed on the laminated surface on which the adhesive layer of the determination rubber layer is laminated (see, for example, FIGS. 6A to 6I), and the lamination thereof is performed. The average peeling force when removing the determination rubber layer from the inner surface of the tire was adjusted by making the area ratio of the non-adhesive region on the surface different as shown in Table 1. Further, the thickness of the adhesive layer was set as shown in Table 1. An acrylic pressure-sensitive adhesive was used as the pressure-sensitive adhesive for the pressure-sensitive adhesive layer.

On the other hand, a tire deterioration determination device of a type in which the determination rubber layer is adhered to the inner surface of the tire with an adhesive was prepared, and the tire deterioration determination device was mounted on the inner surface of the tire (conventional example). As the adhesive, a chloroprene rubber-based adhesive was used.

For pneumatic tires equipped with the tire deterioration determination devices of the above-mentioned conventional examples and Examples 1 to 7, the retention and peeling ease of the determination rubber layer were evaluated by the following methods, and the results are shown in Table 1. Shown.

Judgment rubber layer retention:
Each test tire was assembled to a wheel with a rim size of 22.5 x 7.50 and mounted on a drum tester equipped with a drum with a diameter of 1707 mm, and a running test of 20000 km was conducted under the conditions of air pressure 700 kPa, load 37 kN, and speed 45 km / h. Then, after running, the holding state of the judgment rubber layer was examined. The evaluation result is indicated by "A" when the judgment rubber layer is firmly held on the inner surface of the tire, and is indicated by "B" when the judgment rubber layer is held on the inner surface of the tire but is unstable. , The case where the determination rubber layer is separated from the inner surface of the tire is indicated by “C”.

Ease of peeling off the judgment rubber layer:
The determination rubber layer was peeled off from the inner surface of each test tire, and the ease of peeling off at that time was evaluated. The evaluation result indicates the case where the judgment rubber layer could be easily peeled off by "A", and although the peeling work of the judgment rubber layer was a little difficult, the judgment rubber layer could be collected in a good state. The case is indicated by "B", and the case where the determination rubber layer is deformed or defective due to peeling is indicated by "C".

As is clear from Table 1, in the tires of Examples 1 to 7, the determination rubber layer could be easily peeled off from the inner surface of the tire, and the determination rubber layer could be collected in a good state. Further, in the tires of Examples 1 to 7, the retention of the determination rubber layer was also good. On the other hand, in the conventional tire, although the holding property of the determination rubber layer is good, it is difficult to peel off the determination rubber layer, and the peeled determination rubber layer is greatly deformed.

1 Tread part 2 Side wall part 3 Bead part 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 10 Tire deterioration judgment device 11 Judgment rubber layer 12 Adhesive layer 13 Display part S Tire inner surface

Claims (12)

It is composed of a determination rubber layer made of a rubber composition and an adhesive layer laminated on the determination rubber layer, and the determination rubber layer is attached to the inner surface of the tire in a removable state via the adhesive layer. In the tire deterioration judgment device
A non-adhesive region that does not come into direct contact with the adhesive layer exists on the laminated surface on which the adhesive layer of the determination rubber layer is laminated, and the area ratio of the non-adhesive region on the laminated surface is in the range of 10% to 90%. tire deterioration determination device, characterized in that there. The tire deterioration determination device according to claim 1, wherein the average peeling force when removing the determination rubber layer from the inner surface of the tire is 2.0 N / inch to 100 N / inch. The tire deterioration determination device according to claim 1 or 2, wherein the thickness of the adhesive layer is 0.01 mm to 3.0 mm. The tire deterioration determination device according to any one of claims 1 to 3, wherein at least a part of the non-adhesive region is located at an end portion of the determination rubber layer. The tire deterioration determination device according to claim 4 , wherein the end portion of the determination rubber layer on which the non-adhesive region is arranged has a contour shape different from that of the end portion on the opposite side thereof. The tire deterioration determination device according to claim 4 , wherein the end portion of the determination rubber layer on which the non-adhesive region is arranged has a display portion colored in a color different from that of the determination rubber layer. A pneumatic tire including a tire deterioration determination device composed of a determination rubber layer made of a rubber composition and an adhesive layer laminated on the determination rubber layer, wherein the determination rubber layer is interposed via the adhesive layer. a pneumatic tire that is mounted in a detachable state with respect to the tire inner surface Te,
A non-adhesive region that does not come into direct contact with the adhesive layer exists on the laminated surface on which the adhesive layer of the determination rubber layer is laminated, and the area ratio of the non-adhesive region on the laminated surface is in the range of 10% to 90%. a pneumatic tire characterized by that. The pneumatic tire according to claim 7 , wherein the average peeling force when removing the determination rubber layer from the inner surface of the tire is 2.0 N / inch to 100 N / inch. The pneumatic tire according to claim 7 or 8 , wherein the thickness of the adhesive layer is 0.01 mm to 3.0 mm. The pneumatic tire according to any one of claims 7 to 9, wherein at least a part of the non-adhesive region is located at an end portion of the determination rubber layer. The pneumatic tire according to claim 10 , wherein the end portion of the determination rubber layer on which the non-adhesive region is arranged has a contour shape different from that of the end portion on the opposite side thereof. The pneumatic tire according to claim 10 , wherein the end portion of the determination rubber layer on which the non-adhesive region is arranged has a display portion colored in a color different from that of the determination rubber layer.

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