KR20100010467A - Poly(ethyleneterephthalate) tire cord and tire comprising the same - Google Patents

Abstract

PURPOSE: Polyethylene terephthalate tire cord and a tire including the same are provided to improve ride comfort and adjustability of a vehicle and high driving capacity of the tire, and to offer good modulus and shape stability. CONSTITUTION: Polyethylene terephthalate tire cord is thermally processed for 2 minutes under the load of 0.01 g/d in 180 °C. The extension rates of the polyethylene terephthalate tire cord is 0.5~2.0%. When the load of 4.5kg/2000d is applied to the polyethylene terephthalate tire cord, the tire cord has the extension rate of 3.0~6.0%. The extension rate of the polyethylene terephthalate tire cord is 0.3~1.7% before a thermally process of the polyethylene terephthalate tire cord. The tire cord has a cap ply(4) a belt(5) etc.

Description

Polyethylene terephthalate tire cord and tire comprising same {POLY (ETHYLENETEREPHTHALATE) TIRE CORD AND TIRE COMPRISING THE SAME}

The present invention relates to polyethylene terephthalate tire cords and pneumatic tires comprising the same. More specifically, the present invention relates to a polyethylene terephthalate tire cord and a pneumatic tire including the same, which can improve the high-speed driving performance of the tire, ride comfort and controllability of the tire according to the present invention having excellent modulus and shape stability.

The tire is a composite of fiber / steel / rubber and generally has a structure as shown in FIG. 1. In other words, steel and fiber cords serve to reinforce rubber and form a basic skeletal structure in the tire. In other words, compared to the human body is a bone-like role.

The performance required for the cord as a tire reinforcement is fatigue resistance, shear strength, durability, resilience and adhesion to rubber. Therefore, a cord of appropriate material is used according to the performance required for the tire.

Commonly used materials for the cord are rayon, nylon, polyester, steel, and aramid, and rayon and polyester are used for body plies (also called carcasses) (6 in FIG. 1), and nylon is mainly a cap. In the ply (4 in FIG. 1), and steel and aramid are mainly used in the tire belt portion (5 in FIG. 1).

The following briefly illustrates the tire structure and its characteristics shown in FIG. 1.

Tread (1): This part is to be in contact with the road surface to provide the necessary frictional force for braking and driving, to have good abrasion resistance, to withstand external shocks, and to generate little heat.

Body Ply (or Carcass) (6): A layer of cord inside the tire, which must support loads, withstand impacts, and be resistant to flexing movements while driving.

Belt (5): Located between the body plies, consisting of steel wires in most cases to mitigate external shocks and maintain a wide tread ground to provide excellent driving stability.

Side Wall (3): refers to the rubber layer between the lower part of the shoulder (2) from the bead (9) and serves to protect the body ply (6) inside.

BEAD (9): A square or hexagonal wire bundle with rubber coating on the wire that rests and secures the tire to the rim.

Inner Liner (7): Located on the inside of the tire instead of the tube, this prevents air leakage and enables pneumatic tires.

CAP PLY (4): A special cord paper placed on the belt of some passenger radial tires that minimizes belt movement when driving.

APEX (8): A triangular rubber filler used to minimize the dispersion of beads, to mitigate external impacts, to protect the beads, and to prevent the ingress of air during molding.

Recently, the development of tires suitable for high-speed driving is required with the advancement of passenger cars. Accordingly, high-speed driving stability and high durability of tires are recognized as very important characteristics. In addition, in order to satisfy the characteristics, the performance of the cap ply cord material is more important than ever.

The steel belts present in the tire are generally arranged in an oblique direction, but at high speeds, such steel belts tend to move in the circumferential direction by centrifugal force. At this point, the end of the pointed steel belt breaks rubber or generates cracks. Doing so may cause separation between belt layers and deformation of tire shape. Cap fly acts to increase the high speed durability and driving stability by catching the movement of the steel belt to suppress the separation between layers and form deformation of the tire.

In general, the cap fly cord is mainly made of nylon 66. By the way, in the case of the nylon 66 cord, high shrinkage stress can be expressed under a high temperature environment corresponding to the internal environment of the tire at high speed, thereby wrapping the steel belt and suppressing the movement of the belt. However, the modulus and shape stability are low. Because of this, there is a disadvantage in that partial deformation may occur due to the tire and the vehicle's own load, which may cause a rattling while driving.

In addition, the nylon 66 cord has a low modulus and shape stability, so when the driving speed of the vehicle is suddenly increased, its appearance can be easily deformed, thereby deteriorating the tire. It can reduce the maneuverability or ride comfort.

In comparison, PET high modulus low shrinkage (HMLS) fiber, which is widely used as a general polyethylene terephthalate (PET) fiber or an industrial fiber, has superior modulus and shape stability compared to nylon 66, but these general PET Neither fibers nor HMLS fibers have sufficient modulus and shape stability, so when the vehicle's running speed suddenly increases, its appearance can be relatively easily deformed and the tires deformed. Therefore, even when the cords made of these materials are used as the wet ply cord, the high-speed running performance of the tire, the adjustability or the riding comfort of the tire may not be sufficient.

Accordingly, the present invention is to provide a polyethylene terephthalate tire cord having excellent modulus and shape stability.

In addition, the present invention is to provide a pneumatic tire including the tire cord, not only having excellent high-speed driving performance, but also can further improve the controllability or ride comfort of the vehicle.

The present invention exhibits an elongation rate of 0.5 to 2.0%, preferably 1.0 to 2.0% when subjected to a load of 2.0 kg / 2000d after heat treatment at 180 ° C. for 2 minutes under a load of 0.01 g / d. Provided is a polyethylene terephthalate tire cord that exhibits an elongation of 3.0-6.0%, preferably 4.0-6.0% when loaded.

The present invention also provides a pneumatic tire comprising the tire cord.

Hereinafter, a polyethylene terephthalate stretched yarn, a polyethylene terephthalate tire cord and a tire including the same according to a specific embodiment of the present invention will be described in detail. However, this is presented as an example of the invention, whereby the scope of the invention is not limited, it is apparent to those skilled in the art that various modifications to the embodiments are possible within the scope of the invention.

Additionally, unless otherwise indicated throughout this specification, "comprising" or "containing" refers to including any component (or component) without particular limitation, and refers to the addition of another component (or component). It cannot be interpreted as excluding.

According to one embodiment of the invention, a polyethylene terephthalate (hereinafter referred to as "PET") tire cord having certain properties is provided. This PET tire cord exhibits an elongation of 0.5 to 2.0%, preferably 1.0 to 2.0% when subjected to a load of 2.0 kg / 2000d after heat treatment at 180 ° C. for 2 minutes under a load of 0.01 g / d, and 4.5 kg / When a load of 2000d is applied, the elongation is 3.0 to 6.0, preferably 4.0 to 6.0%.

PET tire cord according to one embodiment of the present invention is subjected to a load of 2.0kg / 2000d or 4.5kg / 2000d under a high temperature of 180 ℃ corresponding to the high-speed running conditions of the tire (these 2.0kg / 2000d or 4.5kg The load of / 2000d can correspond to the low speed running condition or the high speed running condition of the tire, respectively.), And the length deformation does not greatly occur, and the difference in the length deformation when these two loads are respectively applied is not large. Therefore, the PET tire cord has excellent modulus and shape stability, and thus, even if the running speed of the vehicle suddenly increases and the temperature or load applied to the tire cord is suddenly increased, the appearance shape is hardly changed. Therefore, the tire cord can be preferably used as a cap ply cord and the like, and even when the running speed of the vehicle is suddenly increased, it is possible to suppress the deformation of the tire due to the deformation of the tire cord. The vehicle's control and ride comfort can be further improved.

In addition, the PET tire cord exhibits an elongation of 0.3 to 1.7%, preferably 0.7 to 1.7% when a load of 2.0 kg / 2000d is applied before the heat treatment, and 2.0 to 4.0% when a load of 4.5 kg / 2000d is applied. It can represent the elongation rate of.

That is, even when the PET tire cord is subjected to a load of 2.0 kg / 2000d or 4.5 kg / 2000d even under a low temperature corresponding to the tire stop or low-speed driving conditions, the length deformation does not significantly occur, and these two loads may be respectively applied. Not only does the difference in the length strain at the same time is large, but also the difference in the length strain due to the change of temperature is not great even when compared with the elongation rate under the high temperature. Thus, even when the tire cord is rapidly increased in temperature or load, there is little deformation of its appearance. Therefore, the tire cord can minimize the deformation of the tire itself and the deformation of the tire including the same even when the running speed of the vehicle is suddenly increased, thereby further improving the high-speed running performance of the tire or the maneuverability and ride comfort of the tire.

On the other hand, PET tire cord according to an embodiment of the present invention is not particularly limited in form, it may have a form equivalent to the conventional cap ply cord. More specifically, the PET tire cord is a deep cord having a total fineness of 1000 to 5000 denier (d) per cord, a number of plies of 1 to 3, and a twist number of 200 to 500 TPM according to the form of a conventional cap ply cord. It may have a form.

In addition, the PET tire cord is 5 to 8 g / d, preferably 5.5 to 7 g / d strength, 1.5 to 5.0%, preferably 2.0 to 3.5% of the core (elongation at 4.5 kgf load), 10 to 25 %, Preferably 15 to 25% of stretch and 0.5 to 5.0%, preferably 2.0 to 5.0% of shrinkage (177 ° C., 30 g, 2 min). As the tire cord exhibits various physical properties such as strength or elongation in this range, it can be preferably applied as a capfly cord.

The tire cord may be applied as a cap ply cord of the pneumatic tire. The tire to which the cap ply cord is applied has a sudden driving speed of the vehicle, so that the temperature or load on the cap ply cord is rapidly increased. However, the appearance of the cap ply cord is not easily deformed, and thus the tire itself is not easily deformed. Do not. Therefore, the tire not only exhibits high speed driving performance but also greatly improves the controllability and ride comfort of the vehicle. In addition, since the tire cord has various physical properties such as high modulus, shape stability, strength, or elongation that can be preferably used as a capfly cord, the tire to which the capfly cord is applied can exhibit excellent performance.

 However, the above description mainly assumes the case where the PET tire cord according to the embodiment of the invention is used as a cap ply cord, but the use of such a PET tire cord is not limited thereto, and other body ply cords and the like. Of course, it can also be used for purposes.

On the other hand, the above-described PET tire cord is melt-spun PET to produce a non-drawn yarn, stretched the non-drawn yarn to prepare a stretched yarn, after the twisted yarns are twisted yarns immersed in an adhesive to form a tire cord in the form of a deep cord It may be prepared by the method of preparation. The specific conditions or the process of each of these steps can be directly or indirectly reflected on the physical properties of the final tire cord can be produced PET tire cord having the above-described physical properties.

In particular, the polyethylene terephthalate non-drawn yarn having a crystallinity of 25% or more and an amorphous Orientation Factor (AOF) of 0.15 or less is obtained by adjusting the melt spinning condition of the PET, and thus, a stretched yarn is manufactured and used therefrom. It has been found that the above-mentioned PET tire cords can be produced in which the elongation rate itself is not large and the elongation difference is not large when the low or high load is applied under low temperature or high temperature.

PET basically has a crystallized form, and is composed of a crystalline region and an amorphous region. However, the PET non-drawn yarn obtained under controlled melt spinning conditions has a higher degree of crystallization than previously known PET non-drawn yarn due to the orientation crystallization phenomenon, and thus exhibits a high degree of crystallinity of 25% or more, preferably 25 to 40%. Due to such a high degree of crystallinity, PET stretched yarns and tire cords prepared from the PET non-stretched yarns may exhibit high shrinkage stress and modulus.

At the same time, the PET non-drawn yarn exhibits an amorphous orientation index of 0.15 or less, preferably 0.08 to 0.15, which is significantly lower than previously known PET non-drawn yarn. At this time, the amorphous orientation index indicates the degree of orientation of the chains included in the amorphous region in the unstretched yarn, and has a lower value as the matting of the chains in the amorphous region increases. That is, in general, when the amorphous orientation index is lowered, the disorder is increased so that the chains of the amorphous regions become a relaxed structure rather than a tensioned structure, so that the drawn yarn and tire cords made from undrawn yarn have low shrinkage with low shrinkage rate. It will show stress. However, the PET non-drawn yarn obtained under controlled melt spinning conditions contains more crosslinks per unit volume, forming a fine network structure due to the molecular chains which make it slip during the spinning process. For this reason, the PET unstretched yarn can have a strained structure of the chains in the amorphous region while the amorphous orientation index is greatly lowered, thereby showing the developed crystal structure and excellent orientation characteristics.

Therefore, it is possible to manufacture PET stretched yarns and tire cords simultaneously exhibiting a low shrinkage rate and a high shrinkage stress using PET non-drawn yarns exhibiting such high crystallinity and low amorphous orientation index, and furthermore, according to one embodiment of the invention It has been found that having various physical properties (eg, the difference in low elongation and low elongation by temperature or load described above) can provide a PET tire cord exhibiting excellent morphological stability and modulus.

The manufacturing method of such a PET tire cord will be described in each step as follows.

In the tire cord manufacturing method, PET unstretched yarn is first produced by melt spinning PET, which exhibits the above-described high crystallinity and low amorphous orientation index.

In this case, the melt spinning process may be performed under a higher spinning tension to obtain PET non-drawn yarn that satisfies such crystallinity and amorphous orientation index. For example, the melt spinning process may proceed under a spin tension of at least 0.85 g / d, preferably 0.85 to 1.25 g / d. In addition, for example, the rate of melt spinning the PET can be adjusted to 3800 to 5000 m / min, preferably 4000 to 4500 m / min can be adjusted.

As a result of the melt spinning process of PET under such a high spinning tension and optionally high spinning speed, the crystallization degree is increased with the orientation crystallization phenomenon of PET, and the molecular chains forming the PET slide during the spinning process to form a fine network structure. It has been found that PET non-drawn yarns can be obtained that satisfy the crystallinity and amorphous orientation index described above. However, adjusting the spinning speed to 5000 m / min or more is difficult to realize in reality and it is difficult to proceed with the cooling process due to excessive spinning speed.

In the manufacturing process of such PET non-stretched yarns, chips having an intrinsic viscosity of 0.8 to 1.3 dl / g and composed of 90 mol% or more of polyethylene terephthalate can be used as the PET.

As described above, in the manufacturing process of the PET non-stretched yarn, conditions of higher spinning tension and optionally higher spinning speed can be imparted. In order to proceed the spinning step preferably under these conditions, the inherent characteristics of the chip It is preferable that a viscosity is 0.8 dl / g or more. In addition, it is preferable that the intrinsic viscosity is 1.3 dl / g or less in order to prevent the molecular chain cutting and the pressure increase due to the discharge amount in the spin pack due to the rise of the melting temperature of the chip.

In addition, the chip is preferably spun through a mold designed so that the fineness of the monofilament is 2.0 to 4.0 denier, preferably 2.5 to 3.0 denier. In other words, the monofilament should have a fineness of 2.0 denier or more to reduce the possibility of trimming due to interference with each other during the generation and trimming of the yarn during spinning.The fineness of the monofilament should be increased to give a sufficiently high spinning tension by increasing the radiation draft. Is preferably 4.0 denier or less.

In addition, after melt spinning the PET, the unstretched yarn may be manufactured by adding a cooling process. The cooling process is preferably performed by applying a cooling wind of 15 to 60 ° C., and each cooling wind temperature. It is preferable to adjust the cooling air volume to 0.4-1.5 m / s in conditions. Thereby, PET non-drawn yarn satisfying the above-mentioned crystallinity, amorphous orientation index, and the like can be produced more easily.

On the other hand, after manufacturing the PET non-drawn yarn that satisfies the above-described crystallinity and the like through the spinning step, the non-drawn yarn is stretched to prepare a stretched yarn, the stretching step can be carried out under the draw ratio conditions of 1.0 ~ 1.55 or less. have. The PET non-drawn yarn has advanced crystal regions, and amorphous chains also have a low degree of orientation and form a fine network structure. Therefore, when the drawing step is carried out under a high draw ratio condition of more than 1.55, cutting or mousse may occur in the drawn yarn, and thus the final manufactured tire cord may not exhibit desirable physical properties. In addition, when the stretching process is performed under a relatively low draw ratio, the strength of the PET tire cord manufactured therefrom may be partially lowered. However, under an elongation ratio of 1.0 or more, for example, it is possible to manufacture a PET tire cord having a strength of 6 g / d or more suitable for application to a cap fly cord, etc., and thus, the stretching process may be preferably performed under an elongation ratio of 1.0 to 1.55. Can be.

After the drawn yarn is manufactured, the drawn yarn is fused and then immersed in an adhesive to prepare a dip cord. Such a twisted yarn process and an immersion process are in accordance with the conventional PET tire cord manufacturing process conditions and methods.

The tire cords thus prepared may have a form with a total fineness of 1000 to 5000 denier, plies of 1 to 3, twist of 200 to 500 TPM, excellent physical properties as described above, for example, temperature and By load, small elongation and elongation difference, excellent shape stability and modulus can be exhibited.

As described above, the tire cord of the present invention exhibits excellent modulus and form stability, so that deformation hardly occurs even if the temperature and load applied thereto are rapidly increased.

Therefore, when the tire cord of the present invention is used, the tire cord and the tire including the tire can be prevented from being deformed even when the speed of the vehicle is suddenly increased, thereby further improving the controllability and riding comfort of the vehicle together with the high speed running performance of the tire. You can.

Hereinafter, the configuration and operation of the invention through the preferred embodiments of the invention will be described in more detail. However, the scope of the invention is not limited by these embodiments, which are merely presented as an example.

Example 1 (Preparation of PET Tire Cord)

A PET polymer having an intrinsic viscosity of 1.05 dl / g was used, and a non-drawn yarn was prepared by melt spinning and cooling the PET polymer according to a conventional method at a spinning speed of 4500 m / min under a spinning tension of 1.15 g / d. These undrawn yarns were drawn, heat-set and wound at a draw ratio of 1.30 to prepare PET drawn yarns.

PET drawn in Example 1 by twisting two strands of Z-bonded yarns with 430 TPM of S yarns of the same twist number by squeezing yarns of total fineness of 1000 denier manufactured as described above and immersing and passing through RFL adhesive solution, followed by drying and heat treatment. Tire cords were prepared.

The composition and drying and heat treatment conditions of the RFL adhesive solution were the same as those of conventional PET cords.

Example 2-6 (Preparation of PET Tire Cord)

During the manufacturing process of PET stretched yarn, PET stretched yarn was prepared in the same manner as in Example 1 except that the spinning speed, the radial tension, the draw ratio or the intrinsic viscosity conditions were changed as shown in Table 1 below. PET stretched yarn was twisted and twisted in the same manner as in Example 1, immersed in an adhesive solution, and then dried and heat-treated to prepare PET tire cords of Examples 2 to 6, respectively.

TABLE 1

Condition Example 2 Example 3 Example 4 Example 5 Example 6 Spinning speed (m / min) 4000 Same as Example 1 Same as Example 1 3800 4800 Radial tension (g / d) 0.92 0.98 1.23 0.86 1.19 Elongation ratio 1.46 1.24 1.24 1.54 1.16 Intrinsic Viscosity (dl / g) Same as Example 1 0.9 1.2 Same as Example 1 Same as Example 1

Example 7 (Preparation of PET Tire Cord)

Using the drawn yarn obtained in the same manner as in Example 1, except that two strands of Z-bonded yarns with a total twist of 1000 denier and Z-bonded yarn at 260 TPM were twisted together at the same twisted number of S edges. In the same manner, the tire cord of Example 7 was prepared.

Comparative Example 1 (Production of Tire Cord Using High Elasticity Low Shrinkage (HMLS) Fiber)

For the production of undrawn yarn, PET polymer with an intrinsic viscosity of 1.05 dl / g was melt-spun at a spinning speed of 3000 m / min under a radial tension of 0.52 g / d, and the undrawn yarn was drawn at a draw ratio of 1.8 to produce a drawn yarn. Then, the tire cord of Comparative Example 1 was prepared in the same manner as in Example 1.

Comparative Example 2 (Preparation of Tire Cord Using Nylon 66 Fiber)

A non-drawn yarn was prepared by melt spinning and cooling a nylon 66 polymer having a relative viscosity of 3.3 m at a spinning speed of 600 m / min, and a non-drawn yarn was drawn, heat set, and wound at a draw ratio of 5.5 to prepare a drawn yarn using nylon 66 fibers. .

Two twisted yarns of Z-bonded yarn with 310 TPM of twisted yarn of total fineness of 840 denier manufactured as above were fused and immersed in RFL adhesive solution, passed through RFL adhesive solution, and then dried and heat treated to use nylon 66 fibers. The tire cord of Comparative Example 2 was prepared.

The composition and drying and heat treatment conditions of the RFL adhesive solution were the same as those of conventional nylon 66 cord.

First, the crystallization degree and amorphous orientation index (AOF) of Examples 1 to 6 (the non-drawn yarn obtained in Example 7 is the same as the undrawn yarn obtained in Example 1, and thus the measurement is omitted), and the non-drawn yarn obtained in Comparative Examples 1 and 2 are Measured by the method of, the measurement results are summarized in Table 2 below:

Crystallinity: After preparing a density gradient tube using CI ₄ , n-heptane, the density was measured and the crystallinity was measured using the following formula.

PET crystallinity (%) =

(At this time, PET is a constant of ρ _a = 1.336 and ρ _c = 1.457.)

-AOF: AOF was calculated by the following equation using the birefringence measured using a polarizing microscope and the crystal orientation index (COF) measured from XRD.

AOF = (birefringence-crystallinity (%) * 0.01 * crystal orientation index (COF) * 0.275) / ((1-crystallinity (%) * 0.01) * 0.22)

TABLE 2

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Crystallinity (%) 36 30 34 36 28 38 9 2 AOF 0.009 0.093 0.015 0.012 0.120 0.002 0.245 0.002

Referring to Table 2, the non-stretched yarns of Examples 1 to 6 prepared under high spinning tension and spinning speed have high crystallinity and low amorphous orientation index, and show advanced crystal structure and excellent orientation characteristics. It was confirmed that the undrawn yarn of 2 and 2 did not satisfy these characteristics.

The tire cords prepared according to Examples 1 to 7 and Comparative Examples 1 and 2 were measured using a universal tensile tester based on ASTM D885 standard, and elongation rate for each temperature and load was measured. More specifically, first, the elongation at the time when 2.0 kg / 2000d and 4.5 kg / 2000d is applied to the cord at room temperature, respectively, and the elongation rate is measured, and 180 ° C under the initial load of 0.01 g / d to the cord After the heat treatment for 2 minutes in the furnace, the elongation rate when the cord was loaded with 2.0kg / 2000d and 4.5kg / 2000d was measured, respectively.

The elongation rate according to the temperature and the load of each cord thus measured is shown in Tables 3 and 4 below.

TABLE 3

Temperature and load Example 1 (%) Example 2 (%) Example 3 (%) Example 4 (%) Example 5 (%) Before heat treatment (room temperature) 2.0kg / 2000d 1.2 1.0 1.2 1.1 1.0 4.5kg / 2000d 2.9 3.3 3.2 2.9 3.6 After heat treatment (180 ℃, 2 minutes) 2.0kg / 2000d 1.4 1.4 1.4 1.54 1.5 4.5kg / 2000d 5.2 4.8 5.4 4.6 5.2

TABLE 4

Temperature and load Example 6 (%) Example 7 (%) Comparative Example 1 (%) Comparative Example 2 (%) Before heat treatment (room temperature) 2.0kg / 2000d 1.2 0.9 1.4 4.2 4.5kg / 2000d 2.8 2.4 4.6 8.1 After heat treatment (180 ℃, 2 minutes) 2.0kg / 2000d 1.3 1.1 2.0 6.2 4.5kg / 2000d 4.6 4.6 7.3 10.8

Referring to Tables 3 and 4, the tire cords of Examples 1 to 7 manufactured from PET non-stretched yarns exhibiting high crystallinity and low amorphous orientation index are not only smaller in temperature and load-specific elongation than the tire cords of the comparative examples. It is confirmed that the difference in elongation rate by temperature and load is also smaller than that of the tire cord of the comparative example.

From this, it is confirmed that the tire cords of Examples 1 to 7 hardly form deformation even when the temperature and load applied thereto are rapidly increased. Therefore, it is confirmed that the tire cords of Examples 1 to 7 have excellent shape stability and hardly cause deformation of the tire including itself and the tire thereof even when the running speed of the vehicle suddenly increases.

1 is a partial cutaway perspective view showing a configuration of a general tire.

Claims (7)

After heat treatment at 180 ° C for 2 min under 0.01 g / d load, it shows 0.5 ~ 2.0% elongation when 2.0kg / 2000d is applied, and 3.0 ~ 6.0% elongation when 4.5kg / 2000d is applied. Polyethylene terephthalate tire cord which shows. The polyethylene terephthalate tire cord according to claim 1, wherein the polyethylene terephthalate tire cord exhibits an elongation of 0.3 to 1.7% when a load of 2.0 kg / 2000d is applied before the heat treatment, and an elongation of 2.0 to 4.0% when a load of 4.5 kg / 2000d is applied. . The method of claim 1, Polyethylene terephthalate tire cord showing strength of 5 to 8 g / d, heavy toxins (@ 4.5 kgf) and stretch to 10 to 25%. The method of claim 1, Polyethylene terephthalate tire cord having a total fineness of 1000 to 5000 denier, 1 to 3 plies, and 200 to 500 TPM. The method according to any one of claims 1 to 4, Polyethylene terephthalate tire cord as a capfly cord. A pneumatic tire comprising the tire cord according to any one of claims 1 to 4. The method of claim 6, Air-injected tire applying the cord to the cap ply.

Images