JPS60197408A - Radial-ply tire - Google Patents

Abstract

PURPOSE:To secure high strength per area and a high modulus as well as to improve sixing stability and resistance to fatigue, by using a polyethyleneterephtalate system-dip cord having the specified characteristic for carcass plies. CONSTITUTION:A radial-ply tire consists of reinforced plies which dispose cords at almost nearly 90 deg. on an equatorial surface of the tire. It is provided with a troidal carcass ply layer 1 whose both ends engaged bead wires 2. As a carcass in this carcass ply layer 1, it consists of such a fiber as being more than 85mol% in a repetitive structural unit of ethylene terephtalate and containing a high polymerization degree of more than 0.80 in intrinsic viscosity IV, using a polyethyleneterephtalate system-dip cord having upper twisting and lower twisting of 2,000-1,300 in a twist coefficient impregnated with a dip solution for improving its adhesiveness with rubber.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radial tire with a polyester fiber cord having specific high modulus values and thermal properties in the carcass.

The fiber cord used in the carcass of radial tires and bias tires must have comprehensive properties such as heat resistance, fatigue resistance, dimensional stability, adhesion, and elastic modulus, but especially for radial tires. In this case, a fiber cord having a relatively high initial modulus, such as a steel cord, is used for the breaker from the viewpoint of high-speed durability, abrasion resistance, and handling stability. In this case, the carcass cord usually has a relatively high twist coefficient in consideration of fatigue resistance, resulting in large distortion, and as a result, fatigue resistance is inhibited.

Compared to conventional carcass cords, it has a relatively high elastic modulus, high strength, few flat spots, and heat resistance.

Polyester fiber cord is used because it has a good overall balance of properties such as good water resistance and low water absorption, but when used in conjunction with a breaker with a high initial modulus as mentioned above, However, it is insufficient in terms of modulus value, heat shrinkage rate, etc. It has already been proposed to use a low degree of polymerization polyester fiber cord for the carcass as a cord with improved modulus heat shrinkage (Japanese Patent Publication No. 56-3806), but this is due to the low degree of polymerization, resulting in low strength. It had the disadvantage of poor fatigue resistance.

The present invention provides a radial tire using a polyester fiber cord carcass which has higher strength than conventional polyester and has completely improved properties such as modulus heat shrinkage, heat resistance, and fatigue resistance.

On the other hand, as a method for completely improving the dimensional stability of the polymer without completely lowering the degree of polymerization, there is a poyi stretching method as seen in US Pat. No. 4,195,032, but the toughness is completely sacrificed in order to improve the dimensional stability.

Therefore, the present invention has been devised to eliminate such conventional drawbacks, and can further reduce the heat shrinkage rate of polyester dispersion cord, improve fatigue resistance toughness, and use it for carcass plies of radial tires. It has the characteristics of improving the handling stability of the tire and reducing the rolling resistance completely.

That is, the above purpose is (1) that the repeating structural unit of ethylene terephthalate is 8
Melt-spinning a polyester made of a polyester-based polymer of 5 molti or more and having a high degree of polymerization with an intrinsic viscosity of 0.80 or more, preferably 0.80 to 1.20; (2) The spun yarn is completely undrawn. Taking the yarn under conditions such that the single yarn denier is 30 d or less and the birefringence is 0.002 to 0.010; (3) The yarn that has passed through the take-up rolls is completely stretched continuously or after being wound once. Magnification is 5.0 times or more, preferably [6
(4) The quality of the drawn yarn satisfies the following conditions; (a) DT≧9.5r
/d.

Preferably DT≧11. Of/d (B) 12 pieces≧DE≧5chi, preferably 10 pieces≧DE≧5q/b (c) Tα≧160°C 5- More preferably, (b) Birefringence of the fiber Δn≧195X10” (Ho) ) Long period LP ≧ 170A by small-angle X-ray diffraction (f) Single yarn denier of fiber is 4 d or less (5) Twist coefficient 2 for drawn yarn (multifilament yarn)
000 to 1,300, preferably 1,800 to 1,400 to create a raw cord by first twisting and final twisting; (6) Adhesiveness to the whole rubber of the blind fabric woven from the raw cord or the raw cord; (7) Carcass ply is created by calendering the polyester cord fabric obtained as above and sandwiching it between rubber sheets. This is accomplished by combining it with ped wire and rubber to form a radial tire.

According to this method, the repeating structural unit of ethylene terephthalate is made of a polyester polymer having 85 moles or more, and the polyester fiber has an intrinsic viscosity of 0.80 or more = 6- or higher, and is made of a polyester fiber having a high degree of polymerization of 0.80 or more = 6- or more. The twist coefficient to which the dip liquid is attached is 2,000 to 1,300, preferably 1,800 to 1,800 to completely improve adhesion.
Made of polyester dip cord with 1400 ply and ply twist, it has high strength and has all of the following properties at the same time.
An n7 hypopolyester dipped cord with high modulus and significantly improved dimensional stability and fatigue resistance is obtained.

(a) Breaking strength of the dip cord A≧7.5 r/d Preferably A≧8.0 t/d (b) Intermediate elongation FB of the dip cord ≦5% (c) Dry heat shrinkage rate of the dip cord C≦ 5% (d) C≦-B+8.
5 This dipped cord is significantly different from conventional polyester dipped cords in that it has low shrinkage, high modulus, and high strength.

More specifically, the method of the present invention and the characteristics of the fibers obtained by the method will be described.

The polyester that is the raw material for the polyester cord intended in the present invention has an intrinsic viscosity of 0.80 or more, preferably 0.80 when measured at 30°C in a solvent of p-chlorophenol/tetrachloroethane = 3/1 (weight ratio). ~1.20, and 85 or more moles of the structural units, preferably 95 or more moles, are composed of divalent terephthalate, and other structural units that can be mixed in small amounts include diethylene glyco-isophthalic acid, dibenzoic acid, p-tert-
Examples include aromatic dicarboxylic acids such as phenyl-4,4'-dicarboxylic acid and hexahydroterephthalic acid, aliphatic dicarboxylic acids such as adipic acid, and hydroxy acids such as hydroxyacetic acid. It is made into fibers using a spinning method.

Such polyesters may be treated with matting agents, if necessary.
Pigments, light stabilizers, heat stabilizers, antioxidants, antistatic agents,
All dyeability improvers, adhesion improvers, etc. can be included, and all can be used except those that have a serious adverse effect on the properties of the present invention depending on how they are blended.

Usually, the polyester dried to a moisture content of 0.03% or less is spun using an all-melt spinning machine, but preferably an extruder type spinning machine is used. 'The spinning take-off speed is set so that the single fiber denier of the sampled yarn is 30 denier or less and the birefringence is 0.002 to 0.010.

The spinning conditions corresponding to the yarn quality can be determined by optimizing not only the take-up speed but also many factors such as the nozzle hole diameter, the nozzle-quench distance, the intrinsic viscosity of the polymer, and the spinning temperature.

In particular, it is preferable that the basic spinning factor parameters satisfy the following conditions in order to realize the fibers used in the present invention, which have a high degree of polymerization and a small filament denier.

()) Q / yr D” ≧ 23500 (f/cd
-m) (G) V w /V o ≦ 200 (S) LH: 30 to 200 [edit] Body) TA: 280 to 330 (°C) However, in formulas (G) to (2), Q: Single hole Amount of polymer discharged at 9 C9 m] 9-D: Nozzle hole diameter [sub] ■w; Spinning take-off speed Cm/m"J VO: Nozzle discharge linear velocity Cm/m] LH: Heating zone length directly below the nozzle [■] TA: Yarn atmosphere temperature in the heating zone directly below the nozzle [°C] ? Indicates.

When the birefringence of the drawn yarn exceeds 0.010, the cutting node FDT is stably 9.5 f/d or more, preferably 11,0
It does not become a high tenacity yarn of f/d or higher.

When the polymerization ratio of the polymer is constant, it is preferable that the birefringence of the drawn yarn is as small as possible in order to obtain a high-strength yarn. However, if the total birefringence of the drawn yarn is less than 0.002, the spinning operation becomes difficult. It is not desirable because it causes damage.

In addition, if the single yarn denier of the drawn yarn exceeds 30 deniers, it is difficult to stably draw it at a high draw ratio, and the high strength obtained by drawing at a high draw ratio as intended in the present invention. It becomes difficult to use thread sounds.

10- When the undrawn yarn obtained as described above is completely spun continuously or once wound and then stretched, the undrawn yarn first supply roller and the undrawn yarn maintained at 100°C or less are The undrawn yarn is pre-stretched by a factor of 1.10 times or less between the second supply roller and the second supply roller, and then the first step is carried out at a stretching ratio of 40% or more of the total stretching ratio between the second supply roller and the first stretching port. It is preferable to carry out drawing. If necessary, a high temperature pressurized steam jetting nozzle is provided between the undrawn yarn second supply roller and the first drawing roller, and the nozzle temperature is set to 200° C. or higher to blow out all of the high temperature steam. The stretching point is fixed near the hot pressurized steam jet nozzle. Furthermore, when performing the second-stage drawing, a heating device including a slit heater (slit as a thread running path) with an ambient temperature of 170 to 420°C was provided between the first drawing roller and the second drawing roller. The thread is heated while running through the slit in a non-contact state (ambient temperature refers to the temperature inside the slit). It is applied to a second stretching roller. At that time, the entire temperature gradient is set in the slit heater, the atmospheric temperature at the yarn inlet is set to 170°C or higher, the total exit atmospheric temperature is set to 420°C or lower, and the yarn stays in an atmosphere of 200 to 420°C for 0.3 seconds or more. It is preferable to pass the yarn through as much as possible. After the two-stage stretching is completed, dimensional stability can be improved throughout by performing a relaxation treatment of 10% or less at 230-165℃ either continuously without winding or once after winding. It is possible.

The total stretching ratio is set to 5.0 times or more, preferably I'' to 16.0 times or more.

In order to obtain the high tenacity, low elongation yarn used in the present invention,
Stretching is performed at a high draw ratio of 85% or more of the maximum draw ratio, preferably 90 inches or more, so that the elongation at break is 5 to 12. The draw ratio for each sample depends on the orientation degree of each drawn yarn Basically determined by

In addition, the maximum stretching ratio is the maximum stretching ratio k that can be stretched.
Measured with n = 5, and refers to the average value.

The polyester fiber thus obtained has the following properties.

(b) DT≧9.5f/d, preferably DT≧11
．． Of/d (b) 12chi≧DE≧5, preferably 10%≧DB≧
5% Furthermore, the mechanical loss tangent Tanδ measured at 110 C/S
The peak temperature Tα of the main dispersion appearing in the temperature dispersion of is 160
℃ or higher indicates that the amorphous portion has been sufficiently elongated, and can be said to be a reflection of 1) and (b) in terms of the filamentous fine structure.

Furthermore, these characteristics can be manufactured more stably by satisfying the following microstructural parameters.

(b) Δn≧195X10-” (e) Long-period LP by small-angle X-ray diffraction≧170 people) (
e) is Δn1, which represents the average orientation when viewed microscopically.
and L, which is representative of the elongation of crystalline and amorphous parts in the fiber axis direction.
This shows that P is large.

In addition, by setting the single yarn denier of the drawn yarn to 4d or less, the radius of the yarn becomes small, and the difference in heat history and stress history between the inner and outer layers during the spinning and drawing processes is small. As the difference becomes smaller and the potency utilization rate increases, it becomes easier to develop high potency.

One feature of the present invention is that it makes it possible to produce fibers with a high degree of polymerization and a low single denier, thereby making it possible to produce polyester fibers with high strength, low elongation, and high polymerization. It's because it became.

The polyester multifilament yarn obtained above is twisted according to a conventional method to form a green cord.

Furthermore, hot stretching 1 is performed following the dip liquid treatment to completely improve the adhesion between the raw cord or the blind fabric rubber woven from the raw cord.

The inventors of the present invention have carefully studied the process from making these raw cords to dipping treatment, and have made the dip cords highly strong, have a completely low intermediate elongation, and have a low shrinkage rate, which is superior to conventional polyester dip cords. The present inventors have discovered that it is possible to achieve excellent performance that cannot be achieved with conventional methods.

14- That is, in the case of the high-strength, low-elongation polyester fiber used in the present invention, the twist coefficient (Tx tension) is usually 2000, which is often used.
~2200 (for example, 47 t for 840 d/2 twist
urn / 10 cm>, the strength utilization rate of the raw cord decreases, but if the twist coefficient is set in the range of 1300 to 2000, preferably U1400 to 1800, the strength utilization rate is very excellent. ratio? By setting it as low as 0 to 3%, a dip cord with a low shrinkage rate and low intermediate elongation can be obtained.

The intermediate elongation is a measure corresponding to the modulus of the cord, and the fact that the intermediate elongation of the dip cord is low indicates that the modulus of the cord is high.

The feature of the present invention is that the high strength, high modulus, and low elongation yarn is already created by stretching it with molecular chain grapes compared to conventional polyester high strength yarn at the high strength yarn manufacturing stage, and after twisting, In the dipping process, the modulus of the dipped cord is reduced by hot stretching. In other words, since there is no need to lower the intermediate elongation, the load on the cord during the dipping process is reduced, resulting in a high-strength polyester with a low shrinkage rate and low intermediate elongation (high modulus) that was previously unimaginable. The goal is to achieve a system dip chord.

Conventional polyester dip cords have a breaking strength A of 7.5 f/d or more, preferably 8.5 f/d or more. Or
/d or more, there was no material whose intermediate elongation [B and dry heat shrinkage coefficient C each satisfied the lower rudder's formula.

(See Figure 1) (b) B≦5% (c) C55% (d) C≦-B + 8.5 The dip cord characteristics of Sait et al.
A low twist number of 300, more preferably 1,800 to 1,400 can be achieved only under low stretch conditions of a hot stretch ratio of 0 to 3% in the dipping step.

Reducing the number of twists has the advantage of increasing the twisting speed and reducing costs, but according to conventional knowledge, it has the disadvantage of decreasing fatigue resistance.

However, because the dipped cord of the present invention satisfies the formulas (a) to (d), even a low-twist cord has a fatigue resistance higher than that of a conventional cord with a twist number. These properties are evident, for example, in the high residual strength after disk fatigue tests.

The heat treatment temperature is generally in the range of 225-255°C, preferably in the range of 230-245°C. If the heat treatment temperature does not reach 225° C., the heat shrinkage rate of the treated cord will increase, making it impossible to obtain sufficient set, increasing the growth of the tire, and worsening the uniformity of the tire. On the other hand, when the temperature exceeds R5°C, the strength of the treated cord decreases significantly. The heat treatment time is usually 1.
It is 0 to 4.0 minutes, preferably 2.0 to 3.0 minutes. If the heat treatment time does not reach 1.0 minutes, the setting of the treatment cord will be insufficient as with the heat treatment temperature, and if it exceeds 4.0 minutes, the strength will decrease.

As described above, according to the present invention, a polyester dip cord having a high modularity of 1 fiber can be obtained by lowering the intermediate elongation without increasing the heat shrinkability.

However, since the radial tire of the present invention uses a polyester cord with high initial modulus, low heat shrinkage, high strength, heat resistance, and excellent dimensional stability for the carcass, it has improved handling stability, durability, and uniformity of flat spot tires. - It has become possible to significantly improve performance, etc. The breaker of the radial tire of the present invention uses a cord having a relatively high modulus of elasticity, such as a steel cord, an aromatic polyamide fiber cord, or a combination thereof.

Examples of the present invention will be described below, but characteristics and measurement methods not mentioned above are as follows.

<Method for measuring birefringence (Δn)> A Nikon polarizing microscope POH model Ui-sha Berek convensator was used, and a spectral light source activation device (Toshiba 5LS-8-B model) was used as the light source (Na light source). . 5
A sample cut at an angle of 45° to the fiber axis with a length of ~6 m is placed on a glass slide with the cut side facing up. Place the sample slide glass on the rotating stage, adjust the rotating stage so that the sample is at a 45° angle to the polarizer, insert the analyzer, set the dark field, and then turn on the compensator. 30 and count the number of stripes (n pieces). Turn the compensator clockwise and measure the compensator scale a at the point where the sample first becomes darkest.Turn the compensator counterclockwise and measure the compensator scale a at the point where the sample first becomes darkest. (read up to 1/10 scale in both cases), return the compensator to 30, remove the analyzer, measure the diameter d of the sample, and calculate the birefringence (Δ) based on the following formula.
n) is calculated (average value of 20 measurements).

△n=F/d (Fniretardage study r=nλ+ε)λ. =589
．． 3mμ ε: C/100 in Leitz compensator manual
Between 00 and 1.

i: (ab) (: Difference in compensator reading) <Method for measuring intrinsic viscosity> Measurement is performed in a mixed solvent consisting of 75% by weight p-chlorophenol and 25% by weight tetrachloroethane.

The polymer is dissolved in a solvent at room temperature and the viscosity measurements are carried out at 30° C. in an Ostwald Fenske tube.

Intrinsic viscosity is the limit value at which the natural logarithm of the ratio of solution viscosity to solvent viscosity divided by the concentration of the polymer solution in grams of polymer per 100 grams of solution approaches zero concentration.

<Measurement method of strength and elongation properties of fibers and cords> JIS-L1
According to the definition of 017. Take the sample in a skein shape and incubate at 20℃ for 6
After leaving it for 24 hours in a temperature and humidity controlled room with 5% RH, 1
Using Tensilon UTM-4L type tensile testing machine [manufactured by Toyo Baldwin (KK)], the test length was 20 cm, and the tensile speed was 2.
Measured at 0 m/min.

However, the measurement was performed after conditioning the raw cord while it was wound on the ply-twisted bobbin.

<Formula for calculating twist coefficient> Twist coefficient plus number of twists x (denier) T Number of twists: turn/10an Measuring method of disk fatigue> Created by embedding dip cord and vulcanizing using a normal disk fatigue tester. Set the test piece and set the compression ratio to 1.
After undergoing forced fatigue by rotating at a speed of 250 rpm for 48 hours under a stretch ratio of 6.3 inches and an elongation ratio of 6.3 inches, the dip cord was removed from the rubber and its residual strength was measured.

<Method for measuring intermediate elongation> According to the definition of JIS-L1017. Measure the elongation rate under a constant load W (groan). The elongation measurement conditions were strong elongation [according to the measurement conditions of properties. The constant load W is defined by the following formula.

W = 4.5
000 denier, and 2000 denier for cord.

<Specific Gravity> ” A density gradient tube made of n-beptane and carbon tetrachloride was created, and the fully degassed sample was placed in the density gradient tube whose temperature was controlled to 30℃±0.1℃, and it was left for 5 hours. After reading the sample position in the density gradient tube in 21-, the value read on the scale of the density gradient tube was converted into a specific gravity value from the density gradient tube scale to specific gravity calibration graph using a standard glass float, and measured at n = 4. As a general rule, specific gravity values are 4 decimal places.
Read down to the digits.

<Constant length heating thermal stress peak temperature> Trial length 45m, heating rate 20℃/min, initial load 0.05t/
Measure the thermal shrinkage stress from room temperature to the melting temperature under the conditions d, and determine the temperature at which the thermal stress is maximum.

[For details, see Textile Re5earch Jour
nal, vol, 47.

See 732 (1977). ] Single thread denier Measured according to JIS-L1073 (1977).

<Measurement method of dry heat shrinkage rate> A sample was taken in the form of a skein, left in a temperature and humidity controlled room at 20°C and 65% RH for 24 hours or more, and then measured by applying a load equivalent to 0.11/d of the sample. After leaving a sample of length to for 30 minutes in an open air condition at 150°C without tension,
Remove from the oven and leave in a room with the above temperature and humidity for 4 hours.
The above-mentioned load was applied again to the measurement, and the length t was calculated using the following formula.

<Measurement method of fiber long period LP by small-angle X-ray diffraction> Small-angle X
The measurement of the ray scattering pattern is performed using, for example, an X-ray generator manufactured by Rigaku Corporation (RU-3H type). For measurements, the tube voltage was 45KV and the tube current was 70mA.

Monochromatic with copper anticathode and nickel filter fccuKα
(λx = 1°5418A) is used. Attach the fiber sample to the sample holder so that the single threads are parallel to each other. It is appropriate that the thickness of the sample be about 0.5 to 1.0 .mu.m. X-rays are incident perpendicularly to the fiber axes of the fibers arranged in parallel to produce PSP manufactured by Rigaku Denki Co., Ltd.
C
It is measured using a port-ional counter) system. An overview of this system can be found, for example (Po
lmer Journal L vol.

13, 501 (1981)).

The measurement conditions were as follows: 0.3wωxo, 2Mo medium pinhole collimator, distance between sample and probe: 400 seconds, number of MCA (multichannel analyzer) measurement channels: 256, and measurement time: 600 seconds. Data processing is performed by subtracting the air scattering intensity from the measured scattering intensity using moving average processing, and by reading the maximum intensity position, the long-period small-angle scattering angle 2
The fiber long period is calculated from ct according to the following formula. [Second
See figure (A), mountain): In the figure, 1' is the sample, 2' is the pspc.
Glove, 3' is position analyzer, 4' is M
CA and 5' respectively indicate display parts].

λx = 1.5418A The moving average processing is calculated according to the following formula.

However, in the above formula, I(S)N and I(S)i are the measured scattering intensities (intensities minus air scattering intensity) of channel numbers N and l, respectively, and K is the moving average adopted score (
Here, = 7), N - K) 0°N ≦ 256 <Mechanical temperature dispersion> Using Rheovibron manufactured by Toyo Sokki Co., Ltd., initial thread length 4
Secondary, heating rate 2℃/min, sine frequency during measurement 110Hz
The temperature (Tα) at which the loss tangent tanδ=E'/E'' is maximum is determined.

Production Example 1 Using polyethylene terephthalate having the intrinsic viscosity shown in Table 1 as a raw material, spinning was performed under the conditions shown in Table 1 to obtain undrawn yarns having the birefringence shown in Table 1. During spinning, an appropriate amount of spinning oil was applied to the surface of the yarn before taking off the undrawn yarn.

The obtained undrawn yarn was drawn under the conditions shown in Table 2 to obtain drawn yarn having the quality shown in Table 3. Table 3 also shows the yarn quality of a commercially available high-strength grade polyester fiber for tire cord as Comparative Example 2.

25- First Table 26 Consultation 2 Table 3 Next, the drawn yarns of Example 1 and Comparative Example 2 were combined,
A 1000 denier V multifilament yarn was obtained.

49T/10crn, 42 respectively for the resulting yarns
T/10 secondary, and 37T/10crn top and bottom twists were applied to make a 1000d/2ply two-strand cord.

The raw cord thus obtained was immersed in a polyester dip solution consisting of a resorcinol/formalin/latex solution, and then heated at 120°C for 3 minutes. ! Dry with hot air under the stretch of S' 俤.

Subsequently, it was introduced into a hot stretch zone and heated at 240℃.
After 1% and 5% hot stretching in heated air of
A dipped cord was manufactured by performing heat treatment for a second.

The properties of the raw cord and dipped cord according to this production example were as shown in Table 4.

The dipped cord obtained in the present invention has significantly improved strength compared to the dipped cord obtained in the comparative example, and has low intermediate elongation and low dry heat shrinkage, which is a measure of dimensional stability, and has a low dry heat shrinkage rate in the false twist region. The fatigue resistance is far superior to that of the comparative example.

29- As is clear from Table 4, the polyester dipped cord according to the present invention has significantly improved strength and elongation properties as compared to the conventional polyester dipped cord, and also has excellent dimensional stability.

On the other hand, in the disk fatigue test, the cord of the present invention had higher residual strength in the low temperature region and was superior in fatigue resistance.

From the above, it can be clearly understood that the cord of the present invention has higher strength and superior fatigue resistance than conventional cords.

Next, various tires shown in FIG. 3 were manufactured using the polyester dipped cord according to the present invention shown in Table 4. That is, in the tire, bead wires 2 are placed on both the left and right sides of a carcass ply layer 1 consisting of one or more plies, in which cords are woven in the form of a curtain.
is curved into an arc and has a ratio shape. The carcass ply layer 1 is reinforced by providing a breaker layer 4 on its crown portion 3, and these constituent layers are further covered with a rubber layer (tread) 5 to obtain the tire of the present invention. The material of the rubber layer is not particularly limited, and for example, natural rubber, butyl rubber, butadiene rubber, nitrile butadiene rubber, styrene butadiene rubber, isoprene rubber, and blend rubbers thereof in arbitrary proportions can be used.

As clarified by the comparative study of the above Examples and Comparative Examples, the polyester cord used in the tire of the present invention has excellent strength as a yarn itself, and as a result, the tire of the present invention has high strength and durability. Demonstrates excellent performance such as fatigue resistance, and exhibits performance that cannot be obtained with tires using conventional polyester cords◇

[Brief explanation of drawings]

FIG. 1 is a diagram showing the characteristics of the dip cord constituting the tire of the present invention, in which the vertical axis represents the dry heat shrinkage rate, the horizontal axis represents the intermediate elongation, and the shaded area represents the characteristics of the dip cord of the present invention. This is an area that indicates Figure 2 (2) is a schematic diagram showing the arrangement of the sample and film surface in the PSPC system used to measure the fiber long period by small-angle X-ray diffraction in the present invention;
) is a schematic diagram showing a small-angle X-ray diffraction pattern of the fiber of the present invention. FIG. 3 is a half-sectional view of the main part of the tire of the present invention. 1...Carcass ply layer 2...Bead wire 3...Crown part 4...Belt part 5...Tread patent applicant Toyobo Co., Ltd. ,) Ko 21!1 (8) Uta 4 Shizuku & (2 Ba) Haya 3 diagram

Claims (1)

[Scope of Claims] 1. Reinforcing plies arranged at approximately 90 degrees with respect to the equatorial plane of the corded tire, reinforcing the toroidal carcass and the crown portion of the carcass that are secured to the bead wires at both ends. In radial tires with different belt layers,
The carcass is made of fibers made of polyester having a high polymerization ratio of 85 moles or more of ethylene terephthalate repeating structural units and an intrinsic viscosity of 0.80 or more, and a dip liquid is attached to the carcass to completely improve the adhesion with rubber. A polyethylene terephthalate dip cord having a top twist and a bottom twist with a twist coefficient of 2000 to 1300,
A radial tire characterized by using a polyester tip cord having high strength, high modulus, and significantly improved dimensional stability and fatigue resistance, having the following characteristics (a) to (d). (a) Dip cord breaking strength A≧7.5 t/d (
b) Intermediate elongation of dip cord B≦5chi (c) Dry heat shrinkage rate of dip cord C50chi (d) C≦−B + 8
．． 5 2. In claim 1, the breaking strength of the dip cord is 8. A radial tire using a polyester dipped cord having a polyester fiber having an intrinsic viscosity of 0.80 to 1.20. 3. A radial tire according to claim 1 or 2, which uses a polyester dip cord having a twist count of 1,800 to 1,400. 4.% Allowance In claim 1, 2 or 3, 110% of the polyester image fiber constituting the dip cord is
A radial tire using a polyester dip cord in which the peak temperature Tα of the main dispersion appearing in the temperature dispersion of the mechanical loss tangent at 0/S is 160° C. or higher.