JP2010280135A - Method of manufacturing run flat tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a deterioration in physicality by vulcanization return of topping rubber in a belt layer to improve a run-flat durability. <P>SOLUTION: The method includes a heating and vulcanizing process having an inner side heating of heating from the inner cavity side of a tire by filling a heating medium in the inner cavity of the green tire 1 placed in a mold 20 and an outer side heating of heating from the tire outer surface side by the mold 20. In the outer heating, a temperature T1 in a tread contacting part of the mold 20 is kept constant in a range of 150-170°C, and in the inner heating, vapor of 180-210°C is used for a temperature T3 as a heating medium. During a heating and vulcanizing process, by controlling a filling time t3 of the heating medium in a range of 0.3-2.75 min, the maximum achieving temperature T2 of the rubber member in a belt cord vicinity area Y is limited to a range of 155-170°C. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  By specifying the vulcanization conditions in a run-flat tire, the present invention can improve the rubber properties of the topping rubber in the belt ply, particularly the loss tangent and the complex elastic modulus, and can improve the run-flat durability. The present invention relates to a tire manufacturing method.

  As a method of vulcanizing a tire, usually, inside the tire lumen of the raw tire accommodated in the mold is filled with a high-temperature heating medium and the raw tire is heated from the tire lumen side, and through the mold. Then, a heating vulcanization process is performed, which includes outside heating for heating the raw tire from the tire outer surface side. In general, saturated water vapor of 180 to 210 ° C. (about 1050 kPa to 2028 kPa in terms of pressure) is used as the heating medium, and the temperature of the mold is controlled to be substantially constant at 180 to 185 ° C.

  On the other hand, as shown in FIG. 2, for example, as shown in FIG. 2, as a run-flat tire that can travel relatively long distances even when air in the tire escapes due to puncture, the sidewall 3 In addition, a so-called side-reinforcing type having a side-reinforcing rubber layer 9 having a substantially crescent-shaped cross section for supporting a load applied at the time of puncture has been proposed.

  This side-reinforced run-flat tire has a thick sidewall portion 3 and a large rubber volume. Therefore, when vulcanized, it is necessary to extend the vulcanization time as compared with a normal tire (non-run-flat tire). However, when only the vulcanization time is extended, the rubber volume is large, and therefore the tire surface side (including the outer surface side and the inner surface side) is over-vulcanized in order to vulcanize to the inside of the tire. (Over-vulcanization), vulcanization reversion occurs, and the physical properties of the rubber on the surface side are reduced.

  Therefore, in the case of a run-flat tire, the vulcanization time is extended while setting the mold temperature to a lower temperature than the normal temperature, for example, 160 to 170 ° C. However, even in such a case, with the topping rubber of the belt ply, vulcanization reversion is not sufficiently solved, and desired rubber properties (particularly loss tangent and complex elastic modulus) cannot be obtained. There still remains a problem that run-flat durability is lowered, such as causing damage to the belt ply.

The following can be presumed as the cause of the vulcanization return of the belt ply topping rubber.
(A) As the topping rubber of the belt ply, natural rubber (NR) excellent in adhesiveness with a belt cord (steel cord) is used, and this natural rubber has a characteristic of being easily re-vulcanized.
(B) Since heat is transferred quickly through the belt cord (steel cord), the topping rubber is easily vulcanized.
(C) The vulcanization return is determined by the cumulative vulcanization heat energy amount and the maximum temperature reached, and the maximum temperature reached can be lowered by setting the mold temperature to the low temperature. However, due to the extension of the vulcanization time, the cumulative vulcanization heat energy amount has not decreased so much.
And it is estimated that these (a)-(c) do not solve the vulcanization return of the top ply rubber of the belt ply, and the desired physical properties of the rubber cannot be obtained.

JP 2007-83703 A

  Therefore, the present invention sets the mold temperature to a low temperature, and reduces the filling time of the heating medium to suppress the amount of heat from the inner heating. An object of the present invention is to provide a method for producing a run-flat tire that can reduce the ultimate temperature and suppress the deterioration of physical properties due to reversion of the topping rubber and improve the run-flat durability.

In order to solve the above-mentioned problems, the invention of claim 1 of the present application is arranged in a carcass extending from the tread portion to the bead core of the bead portion through the sidewall portion, radially outside the carcass and inside the tread portion. A belt layer, and a side reinforcing rubber layer having a substantially crescent-shaped cross section disposed on the sidewall portion, and the belt layer is formed of a belt ply in which an array of steel belt cords is covered with a topping rubber. A method of manufacturing a run flat tire,
Inside the mold, a raw tire for run-flat tires is housed in a mold, a high-temperature heating medium is filled in the tire cavity of the housed raw tire, and the raw tire is heated from the tire lumen side. A heating vulcanization step including heating and heating the mold by a heat source provided in the mold to heat the green tire from the outer surface side of the tire,
Moreover, in the outer heating, the temperature T1 of the tread contact portion of the mold in contact with the tread portion is kept constant in the range of 150 to 170 ° C. by controlling the temperature to the heat source, and in the inner heating, the temperature as the heating medium is maintained. While using steam with T3 of 180-210 ° C,
In the heating vulcanization step, by adjusting the filling time t3 of the heating medium in the range of 0.3 minute to 2.75 minutes, the distance from the surface of the belt cord is within 3 mm in the cord vicinity region. Limiting the maximum temperature T2 of the tire rubber member to a range of 155 to 170 ° C,
Moreover, the product of the temperature T1 of the mold and the heating vulcanization process time t1 which is the time of the outside heating, the product of the temperature T3 of the heating medium and the filling time t3 of the heating medium. The vulcanization index K1 (unit: ° C / min) of the following formula (1) determined by T3 × t3 (unit: ° C / min) is set in the range of 4950 to 10,000 (unit: ° C / min).
K1 = T1 * t1 + 10 * T3 * t3 --- (1)

  The invention of claim 2 is characterized in that the temperature T1 of the tread contact portion of the mold is less than 165 ° C.

  According to a third aspect of the present invention, the topping rubber of the belt ply includes 60 parts by mass or more of natural rubber (NR) and / or isoprene rubber (IR) in 100 parts by mass of the rubber component.

  In the present invention, the temperature T1 of the tread contact portion, which is the mold temperature, is suppressed to a low temperature of 150 to 170 ° C., and overvulcanization on the tire surface side is suppressed. Furthermore, the heating medium filling time is shortened, and the maximum temperature T2 in the vicinity of the cord is limited to a low temperature range of 155 to 170 ° C. while suppressing the amount of heat energy from the inner heating. These synergistic effects can reduce both the amount of accumulated vulcanization heat energy in the belt ply topping rubber and the maximum temperature reached. As a result, it is possible to suppress deterioration in physical properties due to reversion of the topping rubber, particularly increase in loss tangent and decrease in complex elastic modulus, thereby improving run-flat durability.

It is sectional drawing which shows notionally the metal mold | die used for the manufacturing method of the tire of this invention. It is sectional drawing which shows one Example of the run flat tire formed with the manufacturing method of the tire of this invention. It is sectional drawing which shows the belt ply.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the method for producing a run-flat tire of the present invention is obtained by vulcanizing and molding an unvulcanized raw tire 1 for a run-flat tire in a mold 20 to obtain an already-cured run-flat tire 1A. A method for manufacturing, in which a high-temperature heating medium is filled in a tire lumen of a raw tire 1 accommodated in a mold 20 to heat the raw tire 1 from the tire lumen side, and the mold And a heating vulcanization step including heating the mold 20 by a heat source 24 provided at 20 and heating the green tire 1 from the tire outer surface side.

  As shown in FIG. 2, the run-flat tire 1 </ b> A includes a carcass 6 that extends from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4, the radially outer side of the carcass 6, and the inside of the tread portion 2. And a side reinforcing rubber layer 9 having a substantially crescent-shaped cross section disposed on the sidewall portion 3 and supporting a load when puncturing.

  The carcass 6 is formed of one or more, in this example, one carcass ply, in which a belt cord in which organic fiber carcass cords are arranged at an angle of 75 to 90 ° with respect to the tire circumferential direction is covered with a topping rubber. The The carcass ply 6A includes a series of ply turn-up portions 6b that are turned back from the inner side to the outer side in the tire axial direction around the bead core 5 at both ends of the ply body portion 6a straddling the bead cores 5 and 5. A bead apex rubber 8 for bead reinforcement extending in a tapered manner from the bead core 5 toward the outer side in the tire radial direction is disposed between the main body portion 6a and the ply turn-up portion 6b.

  The belt layer 7 includes two or more sheets in which steel belt cords (steel cords) 10 arranged at an angle of, for example, 10 to 35 ° with respect to the tire circumferential direction are covered with a topping rubber 11 (shown in FIG. 3). In this example, the belt plies 7A and 7B are formed. The belt layer 7 increases the belt rigidity by crossing the belt cords between the plies, and reinforces substantially the entire width of the tread portion 2 with a tagging effect.

  Here, the topping rubber 11 has 60 parts of natural rubber (NR) and / or isoprene rubber (IR) in 100 parts by mass of the rubber component in order to ensure good adhesion to the belt cord 10 (steel cord). NR rubber containing at least part by mass, more preferably at least 75 parts by mass is used. As the remaining rubber, other gen-based rubbers such as styrene-butadiene rubber (SBR) and butadiene rubber (BR) can be used. The topping rubber 11 includes a vulcanizing agent such as sulfur, a reinforcing filler such as carbon black, zinc oxide, an anti-aging agent, a softening agent and the like commonly used in the tire industry in order to obtain desired physical properties. , Stearic acid, a vulcanization accelerator, and the like can be appropriately blended.

  The side reinforcing rubber layer 9 for ensuring the run-flat function has a crescent-shaped cross section extending gradually from the central portion 9a having the maximum thickness toward the inside and the outside in the tire radial direction. The radially inner end 9b overlaps with the bead apex rubber 8 inside and outside in the tire axial direction, and the radially outer end 9c overlaps with the belt layer 7 both inside and outside in the tire radial direction. The side reinforcing rubber layer 9 is disposed on the tire lumen side of the ply main body 6a. Therefore, when the sidewall portion 3 is bent and deformed, a compressive load mainly acts on the side reinforcing rubber layer 9, and a tensile load mainly acts on the carcass cord of the carcass ply 6A. Since the rubber is strong against compressive load and the cord is strong against tensile load, the side reinforcing rubber layer 9 as described above efficiently increases the bending rigidity of the sidewall portion 3 and further increases the vertical deflection of the tire during run flat running. It can be effectively reduced.

  Although the side reinforcing rubber layer 9 is not particularly defined, its maximum thickness is in the range of 5 to 10 mm, which causes an increase in the rubber volume of the tire. Therefore, when the run flat tire 1A having such a side reinforcing rubber layer 9 is vulcanized in the mold 20, it is necessary to make the conditions of the heat vulcanization process different from those of the normal tire. Become.

  Therefore, in the present invention, in the outside heating, the temperature T1 of the tread contact portion of the mold 20 in contact with the tread portion 2 (hereinafter sometimes referred to as mold temperature T1) is kept constant in a low temperature range of 150 to 170 ° C., In the inner heating, a constant water vapor is used as the heating medium at a temperature T3 in the range of 180 to 210 ° C., and the filling time t3 of the heating medium is adjusted in the range of 0.3 to 2.75 minutes. This restricts the maximum temperature T2 of the rubber member in the cord vicinity region Y to a range of 155 to 170 ° C.

  As conceptually shown in FIG. 1, the mold 20 includes an upper side mold 20U that forms one sidewall outer surface of the tire 1A, a lower side mold 20L that forms the other sidewall outer surface, and a tread outer surface. And a tread mold 20A for forming a tire, and the split surfaces of the molds 20U, 20L, and 20A are in contact with each other, thereby forming a vulcanizing chamber 21 for accommodating a tire that forms a contour shape of a product tire. Each mold 20U, 20L, 20A is provided with a heat source 22 such as an electric heater or a steam jacket, and is heated to a predetermined temperature by the heat source 22. In this example, the case where the heat source 22 is a steam jacket 22J is exemplified, and the mold temperature T1 of the tread contact portion is controlled by controlling the temperature of saturated steam supplied from the boiler to each steam jacket 22J to be constant. The temperature is constantly controlled in a low temperature range of 150 to 170 ° C.

  A central mechanism 23 concentric with the tire shaft is disposed at the center of the mold 20. The central mechanism 23 is provided with a supply port 24a and a discharge port 24b for supplying and discharging a heating medium for inner heating to the vulcanizing chamber 21, and in this example, a heating medium for inner heating and A rubber bag-like bladder 25 is attached to prevent direct contact with the tire. Further, the supply port 24a is provided with a heating pipe 27A for heating the raw tire 1 by supplying the heating medium from a heating medium supply source (boiler) 26 for inner heating to the vulcanizing chamber 21, and an inner side. After the heating, a pressurizing medium 27 is connected to pressurize the raw tire 1 at a high pressure by continuously supplying the pressurizing medium from the pressurizing medium supply source 28 to the vulcanizing chamber 21. In FIG. 1, reference numerals 30A and 30B denote exhaust pipes connected to the discharge port 24b. One of the exhaust pipes 30A is negatively pressurized when the vulcanized tire is taken out from the mold 20, and the bladder A vacuum 31 for folding 25 is connected. Reference numeral 32 denotes an on-off valve.

  As the heating medium for the inner heating, saturated steam having a temperature T3 of 180 to 210 ° C. is used as in the conventional case. If the temperature T3 is less than 180 ° C, the saturated water vapor pressure becomes lower than 1049.84 kPa (10.36 atm), and the force for pressing the tire against the mold 20 is insufficient, resulting in poor molding and uniformity and appearance quality. Cause a decline. When the temperature exceeds 210 ° C., the saturated water vapor pressure becomes higher than 2028.46 kPa (20.02 atmospheres), so that the heating pipe 27A is required to have high pressure resistance, which causes an increase in equipment cost and maintenance cost.

  In the heat vulcanization step, outside heating by the mold 20 at the temperature T1 and inside heating by the heating medium at the temperature T3 are performed, and the filling time t3 of the heating medium for the inside heating is set to 0.3 minutes to 2 minutes. By adjusting within a range of .75 minutes, the maximum attainable temperature T2 of the rubber member of the tire in the cord vicinity region Y is limited to a range of 155 to 170 ° C. The “cord vicinity area Y” means an area in which the distance L from the surface of the belt cord 10 is within 3 mm, as shown in FIG. The rubber member in the cord vicinity region Y can be said to be a portion that is particularly prone to overvulcanization because heat is transmitted quickly through the belt cord during the heat vulcanization process.

  Here, in the outside heating, the mold temperature T1 is set to 150 to 170 ° C., which is lower than the conventional temperature, so that the temperature gradient when heat is transferred to the inside of the tire becomes gentle. Therefore, even when the run flat tire 1A having a large rubber volume is vulcanized, the inside of the tire can be vulcanized while suppressing over-vulcanization of the tire surface side.

  In the inner heating, the filling time t3 of the heating medium is shortened to 2.75 minutes or less, and the maximum temperature T2 in the cord vicinity region Y is set to a low temperature range of 155 to 170 ° C. while suppressing the amount of heat energy from the inner heating. Restricted. Therefore, it is possible to effectively reduce both the maximum temperature reached in the topping rubber 11 and the amount of accumulated vulcanization heat energy, and the physical properties are lowered due to the reversion of the topping rubber 11, particularly the loss tangent is increased and the complex elasticity is increased. It is possible to suppress a decrease in rate.

  Here, when the mold temperature T1 exceeds 170 ° C., the temperature gradient becomes steep and over vulcanization is caused on the tire surface side. Further, it is necessary to reduce the amount of heat energy due to the inner heating by decreasing the filling time t3 as the amount of heat energy due to the outer heating increases, whereby the inner liner rubber layer 15 disposed on the tire lumen surface side, the carcass No. 6 topping rubber, side reinforcing layer 9 and the like tend to be insufficiently vulcanized. Alternatively, the maximum temperature T2 exceeds the upper limit, causing the topping rubber 11 to return to vulcanization. On the contrary, when the mold temperature T1 is lower than 150 ° C., the productivity is remarkably lowered, for example, the vulcanization time is greatly increased. From such a viewpoint, the upper limit of the temperature T1 is preferably less than 165 ° C, more preferably 163 ° C or less, and further preferably 160 ° C or less.

  When the maximum temperature T2 exceeds 170 ° C. and the filling time t3 exceeds 2.75 minutes, the amount of heat energy due to the inner heating becomes large, and the maximum temperature reached and the cumulative value of the topping rubber 11 is increased. The amount of vulcanization heat energy increases, and the vulcanization return of the topping rubber 11 cannot be suppressed. Conversely, when the temperature is lower than 155 ° C. and when the filling time t3 is less than 0.3 minutes, the amount of heat energy due to the inner heating becomes too small, and the inner liner rubber layer 15 disposed on the tire lumen surface side, The topping rubber of the carcass 6 and the side reinforcing layer 9 and the like tend to be insufficiently vulcanized. From such a viewpoint, it is preferable that the maximum temperature T2 has an upper limit value of 165 ° C. The lower limit of the filling time t3 is preferably 0.5 minutes or more, and the upper limit is preferably 2.5 minutes or less, more preferably 2.0 minutes or less.

  In the heating vulcanization step, the inner heating is performed only during the filling time t3 from the start of the heating vulcanization step when the mold 20 is closed, whereas the outer heating is performed from the start of the heating vulcanization step, This is performed throughout the heat vulcanization process time t1 until the end of the heat vulcanization process in which the mold 20 is opened. Accordingly, the outside heating time is the heating vulcanization process time t1.

In the heating vulcanization step, the product T1 × t1 (unit: ° C / min) of the mold temperature T1 and the heating vulcanization step time t1, the temperature T3 of the heating medium for inner heating, and the filling time t3 thereof. The vulcanization index K1 (unit: ° C / min) of the following formula (1) determined by the product T3 × t3 (unit: ° C / min) is in the range of 4950 to 10000 (unit: ° C / min).
K1 = T1 * t1 + 10 * T3 * t3 --- (1)
If the vulcanization index K1 exceeds 10,000 (unit: ° C./min), the topping rubber 11 tends to return to vulcanization, the loss tangent increases, the heat generation deteriorates, the complex elastic modulus decreases, and the run flat durability Incurs the disadvantage of lowering. On the other hand, if the temperature is below 4950 (unit: ° C / min), the center of the side reinforcing layer 9 tends to be insufficiently vulcanized, resulting in insufficient rubber hardness, reducing the load carrying capacity and increasing loss tangent and generating heat. Reduces run-flat durability, such as deterioration of performance. In recent years, in order to reduce rolling resistance, silica tends to be added to the tread rubber as a reinforcing agent as in this example. However, when the vulcanization index K1 is less than 4950 (unit: ° C / min), the vulcanization is slow. The tread rubber blended with silica does not reach the original rubber properties, resulting in a disadvantage that steering stability and wear resistance are lowered.

  Here, a method for limiting the maximum temperature T2 to a range of 155 to 170 ° C. by adjusting the filling time t3 of the heating medium will be described.

  During vulcanization molding, the tread portion 2 is heated from both sides by the amount of heat supplied from the mold 20 and the amount of heat supplied from the heating medium, and the temperature of the cord vicinity region Y located inside the tread increases with time. To rise. At this time, the temperature of the outer surface of the tread is the same as the temperature T1 of the tread contact portion of the mold 20 and is constant in the range of 150 to 170 ° C., and the temperature of the inner surface of the tread is the same as the temperature T3 of the heating medium. It becomes constant in the range of 180 to 210 ° C.

Therefore, first, the temperatures T1 and T3 are set, and a preliminary vulcanization experiment of the sample tire is performed under the temperature conditions. The sample tire is prepared from tires of the same lot, and a temperature sensor such as a thermocouple is attached to the cord vicinity region Y. In the preliminary vulcanization experiment, the filling time t3 of the heating medium is made different, and the temperature-time curve in the cord vicinity region Y is measured every different filling time t3. And from the data of the various temperature-time curves obtained, the filling time t3 is set so that the maximum temperature T2 in the cord vicinity region Y is in the range of 155 to 170 ° C.
At this time, for setting the filling time t3, it is necessary to consider the vulcanization time t1, and the vulcanization index K1 (= T1 × t1 + 10 × T3 × t3) is 4950 to 10,000. It is set within the range of (unit ° C / min).

  As described above, the relationship between the temperatures T1, T2, T3 and the filling time t3 is grasped by the preliminary vulcanization experiment, and the other tires in the same lot are vulcanized under the vulcanization conditions set thereby.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

  Using the vulcanization method according to the present invention, a passenger car run flat tire (tire size 245 / 40ZR18) having the tire structure shown in FIG. 2 was prepared based on the specifications in Table 1, and the run flat durability of each sample tire was Tested sex. Further, a sample of the topping rubber of the belt ply was cut out from the sample tire, and its complex elastic modulus E * and loss tangent (tan δ) were measured and compared with each other. Except for the vulcanization conditions in Table 1, they are substantially the same. As the topping rubber for the belt layer, rubber having a natural rubber content of 100% by mass in the rubber component is used.

(1) Complex elastic modulus E *, loss tangent (tan δ):
Using a viscoelastic spectrometer, the complex elastic modulus E * and loss tangent (tan δ) of a rubber sample at 30 ° C. were measured under conditions of an initial strain of 10%, a dynamic strain of 2%, and a frequency of 10 Hz. The higher the complex elastic modulus E * and the lower the loss tangent (tan δ), the less the reversion and the more preferable.

(2) Run-flat durability Each test tire was run on a drum tester under the following conditions in a puncture state where the inner pressure was zero with the rim assembled on a regular rim (18x8J) from which the valve core had been removed. The running time until damage occurred was measured. The results are indicated by an index with Conventional Example 1 as 100. The larger the value, the better.
Drum diameter: 1.7m
Load: 4.5kN
Travel speed: 80km / H

  In the tires of the examples, the physical properties of the topping rubber of the belt layer due to reversion (reduction in complex elastic modulus E * and increase in loss tangent) are suppressed, and run-flat durability is greatly improved. Can be confirmed.

DESCRIPTION OF SYMBOLS 1 Raw tire 2 Tread part 3 Side wall part 4 Bead part 5 Bead core 6 Carcass 7 Belt layers 7A and 7B Belt ply 9 Side reinforcement rubber layer 10 Belt cord 11 Topping rubber 20 Mold 22 Heat source Y Area near the cord

Claims (3)

A carcass extending from the tread portion through the sidewall portion to the bead core of the bead portion, a belt layer disposed radially outside the carcass and inside the tread portion, and a substantially crescent-shaped cross section disposed on the sidewall portion A side reinforcing rubber layer, and the belt layer is formed from a belt ply in which an array of steel belt cords is covered with a topping rubber.
Inside the mold, a raw tire for run-flat tires is housed in a mold, a high-temperature heating medium is filled in the tire cavity of the housed raw tire, and the raw tire is heated from the tire lumen side. A heating vulcanization step including heating and heating the mold by a heat source provided in the mold to heat the green tire from the outer surface side of the tire,
Moreover, in the outer heating, the temperature T1 of the tread contact portion of the mold in contact with the tread portion is kept constant in the range of 150 to 170 ° C. by controlling the temperature to the heat source, and in the inner heating, the temperature as the heating medium is maintained. While using steam with T3 of 180-210 ° C,
In the heating vulcanization step, by adjusting the filling time t3 of the heating medium in the range of 0.3 minute to 2.75 minutes, the distance from the surface of the belt cord is within 3 mm in the cord vicinity region. Limiting the maximum temperature T2 of the tire rubber member to a range of 155 to 170 ° C,
Moreover, the product of the temperature T1 of the mold and the heating vulcanization process time t1 which is the time of the outside heating, the product of the temperature T3 of the heating medium and the filling time t3 of the heating medium. A run-flat tire characterized in that the vulcanization index K1 (unit: ° C / min) of the following formula (1) determined by T3 × t3 (unit: ° C / min) is in the range of 4950 to 10,000 (unit: ° C / min). Manufacturing method.
K1 = T1 * t1 + 10 * T3 * t3 --- (1)   The method for manufacturing a run-flat tire according to claim 1, wherein a temperature T1 of a tread contact portion of the mold is less than 165 ° C.   The run flat according to claim 1 or 2, wherein the topping rubber of the belt ply contains 60 parts by mass or more of natural rubber (NR) and / or isoprene rubber (IR) in 100 parts by mass of a rubber component. Tire manufacturing method.

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