KR101231093B1 - Undrawn poly(ethyleneterephthalate) fiber, drawn poly(ethyleneterephthalate) fiber, and tire-cord comprising the same - Google Patents

Abstract

The present invention relates to a polyethylene terephthalate unstretched yarn, a stretched yarn, and a tire cord including the same, which enables the provision of a capfly-coated cord having improved modulus and thus excellent shape stability.

The polyethylene terephthalate undrawn yarn may have a crystallinity of 25% or more, a birefringence of 0.085 to 0.11, an amorphous orientation index (AOF) of 0.15 or less, and a melting point (Tm) of 258 ° C or more.

PET, unstretched yarn, stretched yarn, fine structure

Description

ETRAWN POLY (ETHYLENETEREPHTHALATE) FIBER, DRAWN POLY (ETHYLENETEREPHTHALATE) FIBER, AND TIRE-CORD COMPRISING THE SAME}

The present invention relates to polyethylene terephthalate undrawn yarn, drawn yarn and a tire cord comprising the same. More specifically, the present invention relates to a polyethylene terephthalate undrawn yarn, drawn yarn and a tire cord comprising the same, which enables the provision of a capfly-coated or the like which exhibits improved modulus and thus excellent 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.

Currently commonly used materials for the cord include rayon, nylon, polyester, steel, and aramid, and rayon and polyester are used for body ply (also called carcass) (6 in FIG. 1), and nylon is mainly used. In the cap ply (4 in FIG. 1), and steel and aramid are mainly used for 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. In the case of the nylon 66 cord, high shrinkage stress is 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, these nylon 66 cords have low modulus and glass transition temperatures at high temperatures, and thus low morphological stability, which may result in partial deformation due to tires and automobiles' own loads, which may cause them to rattle during driving. There are disadvantages.

In order to solve these disadvantages, polyethylene terephthalate (PET) cord, which has a high modulus, has been used as a cap ply cord because of its relatively high modulus, but a cord made of general PET fiber has a low shrinkage stress to effectively move the steel belt. It was difficult to suppress, which made it difficult to apply as a capfly cord. Moreover, since the cords made of such general PET fibers also do not have sufficient form stability, when the driving speed of the vehicle is changed and the load applied to the cords made of these materials is changed, the appearance form can be relatively easily deformed to deform the tire. .

In addition, in the case of a cord made of PET High Modulus Low Shrinkage (HMLS) fiber, which is widely used as a fiber or an industrial fiber, it may exhibit high shrinkage stress as compared to a cord made of the general PET fiber. As modulus is lowered and morphological stability is lowered, disadvantages such as the nylon 66 cord may still occur.

Accordingly, the present invention is to provide a polyethylene terephthalate unstretched yarn and a stretched yarn that enables the provision of a cap ply cord and the like exhibiting improved modulus and excellent shape stability.

The present invention also provides a method for producing the polyethylene terephthalate stretched yarn.

In addition, the present invention is to provide a polyethylene terephthalate tire cord that exhibits excellent morphological stability and can be preferably applied to a cap ply cord.

The present invention also provides a tire comprising the polyethylene terephthalate tire cord.

The present invention provides a polyethylene terephthalate undrawn yarn having a crystallinity of 25% or more, a birefringence of 0.085 to 0.11, an amorphous Orientation Factor (AOF) of 0.15 or less, and a melting point (Tm) of 258 ° C or more.

The present invention also provides a polyethylene terephthalate stretched yarn comprising at least 90 mol% of polyethylene terephthalate, having a crystallinity of at least 40%, and having a birefringence of 0.12 to 0.16.

The present invention also provides a polyethylene terephthalate tire cord including the polyethylene terephthalate stretched yarn.

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

Hereinafter, a polyethylene terephthalate non-drawn yarn, a stretched yarn, a tire cord, a manufacturing method thereof, and a tire including the same according to a specific embodiment of the present invention will be described in detail. It will be apparent to those skilled in the art, however, that this is not intended to limit the scope of the invention, which is set forth as an example of the invention, and that various modifications may be made to the embodiments within the scope of the invention.

In addition, throughout this specification, "comprising" or "containing ", unless specifically stated, refers to including any and all components (or components) Can not be interpreted as excluding.

Polyethylene terephthalate (hereinafter referred to as "PET") tire cord is melt-spun spinning the polymer PET to produce a non-drawn yarn, stretched to obtain a stretched yarn, and then twisted PET PET yarn and immersed in an adhesive It may be prepared in dipcode form.

Therefore, the properties of the undrawn yarn produced through melt spinning of the PET and the drawn yarn produced by drawing them are directly or indirectly reflected in the physical properties of the PET tire cord.

As a result of the experiments of the present inventors, as tire cords are manufactured from PET non-stretched yarns and / or stretched yarns having predetermined characteristics, PET tire cords exhibiting improved modulus and form stability can be obtained which can be preferably used as a capfly cord. Turned out to be.

In accordance with one embodiment of the present invention, there is provided a PET non-stretched yarn having a predetermined characteristic. The PET non-drawn yarn may have a crystallinity of 25% or more, a birefringence of 0.085 to 0.1, an amorphous orientation index of 0.15 or less, and a melting point (Tm) of 258 ° C or more.

PET that forms the unstretched yarn may be added with various additives in the manufacturing step, it is preferable that at least 90 mol% or more PET polymer to include the physical properties of PET suitable for the tire cord. Hereinafter, the term PET refers to the case where the PET polymer is 90 mol% or more without any special explanation.

PET non-drawn yarn according to an embodiment of the present invention was prepared under the controlled melt spinning conditions described below to exhibit a high degree of crystallinity of 25% or more and a low amorphous orientation index (AOF) of 0.15 or less.

The PET polymer constituting the unstretched yarn 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 (usually crystallized to less than 7%) due to the orientation crystallization phenomenon, preferably 25 to 40%. High crystallinity of%. Due to this high degree of crystallinity, PET drawn yarns and tire cords made from the PET non-drawn 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. In general, when the amorphous orientation index is lowered, the disorder is increased so that the chains in the amorphous region become a relaxed structure rather than a tensioned structure, so that the drawn yarn and tire cords manufactured from the undrawn yarn have low shrinkage stress with low shrinkage. Will be displayed. 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 produce PET stretched yarn and tire cord simultaneously exhibiting low shrinkage rate and high shrinkage stress by using PET non-drawn yarn showing such high crystallinity and low amorphous orientation index. Therefore, using the PET non-stretched yarn, a PET tire cord can be obtained that exhibits higher modulus and thus excellent morphological stability, but also exhibits high shrinkage stress. Since the tire cord exhibits excellent shape stability and can effectively suppress the movement of the steel belt in the tire, the tire cord can be suitably applied as a cap ply cord or the like.

On the other hand, PET non-drawn yarn according to an embodiment of the present invention may exhibit a crystallinity of 25% or more, preferably 25 to 40%, may have a birefringence of 0.085 to 0.1, the amorphous orientation index of 0.15 or less (Amorphous Orientation Factor, AOF) and may have a melting point of 258 ° C or higher. As described above, using the non-stretched yarn having high crystallinity and excellent molecular orientation characteristics, it is possible to provide a stretched yarn and tire cord which can be preferably used for cap ply as it has high modulus and shrinkage stress. have.

In addition, it is preferable that the PET non-drawn yarn has a specific heat of crystallinity (ΔH) of 42 to 50 J / g, the (010) plane spacing of the microcrystals calculated from the XRD measurement peak is 51 to 57 Å, and the (110) plane spacing is It is preferable that it is 45-50 mm and the (100) interval is 42-50 mm. PET unstretched yarn that satisfies these characteristics can be made to have a higher degree of crystallinity and more excellent orientation properties of the molecule, from which can be obtained PET stretch yarn and tire cord that can be more suitably applied to the capfly cord.

On the other hand, according to another embodiment of the invention, there is provided a PET drawn yarn that can be obtained from the PET non-drawn yarn as described above. The PET stretched yarn includes 90 mol% or more of polyethylene terephthalate, the crystallinity is 40% or more, more preferably 40 to 50%, and the birefringence may be 0.12 to 0.16. Such PET stretch yarn and tire cords manufactured using the same may have high modulus and shrinkage stress, and thus may be preferably applied to a cap ply cord or the like.

That is, PET stretched yarn according to another embodiment of the present invention is manufactured using PET non-stretched yarn having high crystallinity and excellent molecular orientation characteristics in the amorphous region, and thus the crystal structure may be developed to have a crystallinity of 40% or more. May be 40 to 50%. Due to this, such PET stretched yarns and tire cords obtained therefrom may have high modulus and shrinkage stress. However, if the degree of crystallinity is excessively increased, for example, exceeding 60%, the strength is excessively increased, resulting in poor workability and flexibility, and the excessive fatigue rigidity of the tire cord resulting therefrom greatly reduces the tire physical properties. Long-term use of the cord can be difficult.

In addition, the PET stretched yarn may have an amorphous Orientation Factor (AOF) of 0.35 or less, and among them, 0.01 to 0.2. As described above, the amorphous orientation index indicates the degree of orientation of the amorphous chains. In general, the lower the amorphous orientation index, the lower the stretched yarn exhibits the low shrinkage stress because the molecular chains in the amorphous region are relaxed. Can occur. However, the PET stretched yarn according to another embodiment of the present invention may have a structure in which the chains of the amorphous region are tensioned while the molecular chains form a fine network structure during the formation process of the non-stretched yarn described above, while the amorphous orientation index is greatly lowered. Therefore, such PET stretched yarn may exhibit high shrinkage stress while having high modulus and low shrinkage rate. Therefore, the tire cord obtained therefrom can be preferably used as a capfly cord or the like.

And, PET stretched yarn according to another embodiment of the invention is (010) plane spacing of the microcrystalline calculated from the XRD measurement peak is 48 to 60 mm 3, (110) plane spacing is 42 to 50 mm 3, (100) plane spacing It is preferable that it is 38-50 microseconds. As a result, the degree of crystallinity of PET stretched yarn may be higher and the orientation properties of molecules may be more excellent, and thus tire cords having excellent physical properties such as higher modulus and shrinkage stress may be obtained.

On the other hand, PET stretched yarn according to another embodiment of the invention as described above may be prepared by melt spinning the PET to produce a non-drawn yarn, a method of stretching the non-drawn yarn, as described above, the specifics of each step Conditions or a method of proceeding may be directly or indirectly reflected on the physical properties of the PET stretched yarn can be produced PET stretched yarn having the above-described properties.

In particular, by controlling the conditions of melt spinning the PET to obtain a PET non-drawn yarn having a crystallinity of 25% or more, the amorphous orientation index of 0.15 or less, by using this, PET stretched yarn according to another embodiment of the invention described above Turned out to be. More preferably, the PET drawn yarn is an undrawn yarn according to one embodiment of the invention, that is, the crystallinity is 25% or more, the birefringence is 0.085 to 0.11, the amorphous orientation index is 0.15 or less and the melting point (Tm) is 258 ℃ It can be more than that. That is, as described above, by using the PET non-drawn yarn having a high degree of crystallinity and low amorphous orientation index, it is possible to obtain a PET drawn yarn according to another embodiment of the invention showing a very developed crystal structure and excellent orientation properties. Therefore, the PET stretched yarn and the tire cord obtained therefrom exhibit high modulus and shrinkage stress at the same time, and thus can be preferably applied to a capfly cord or the like.

When explaining the manufacturing method of the PET stretcher in more detail for each step as follows.

In the production method of the PET stretched yarn, first, PET non-drawn yarn, preferably PET non-drawn yarn according to an embodiment of the present invention exhibiting the above-described high crystallinity and low amorphous orientation index by melt spinning PET.

In this case, the melt spinning process may be performed under higher spinning tension to obtain PET non-drawn yarn that satisfies high crystallinity and low 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 1.2 g / d. In addition, in order to obtain such a high spinning tension, for example, the rate of melt spinning the PET can be adjusted to 3800 to 5000 m / min, preferably to 4000 to 4500 m / min.

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

As described above, in the manufacturing process of the PET non-stretched yarn, conditions of higher spinning speed and spinning tension can be given. In order to proceed the spinning step under these conditions, the intrinsic viscosity of the chip is 0.8 dl / It is preferable that it is g or more. However, 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 amount of discharge from 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. That is, in order to reduce the possibility of trimming due to interference between each other during the generation of trimming and cooling during spinning, the denier of the monofilament should be 2.0 denier or more, and the fineness of the monofilament in order to give a high spinning tension by increasing the radiation draft Is preferably 4.0 denier or less.

Further, after the PET is melt-spun, the PET non-drawn filament can be produced by adding a cooling step. It is preferable to proceed with such a cooling process by the method of adding the cooling wind of 15-60 degreeC, and it is preferable to adjust the cooling air quantity to 0.4-1.5 m / s in each cooling wind temperature conditions. As a result, it is possible to more easily manufacture the PET unstretched yarn exhibiting all the physical properties according to one embodiment of the invention.

On the other hand, after producing the PET non-drawn yarn that satisfies the above-described crystallinity and amorphous orientation index through this spinning step, the non-drawn yarn is drawn to prepare a drawn yarn. At this time, the stretching step may proceed under a draw ratio condition of 1.0 ~ 1.55. The PET unstretched yarn has advanced crystal regions, and chains of amorphous regions also have a low degree of orientation and form fine networks. Therefore, when the drawing process 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, PET drawn yarn manufactured through the above-described manufacturing method is also difficult to exhibit desirable physical properties. In addition, when the stretching process is performed under a relatively low stretching ratio, the strength of the PET stretched yarn and tire cord manufactured therefrom may be partially lowered. However, under an elongation ratio of 1.0 or more, for example, since it is possible to manufacture a PET tire cord having a strength of 6 g / d or more suitable for application to a capply cord or the like, the stretching process may be preferably performed under an elongation ratio of 1.0 to 1.55. Can be.

In addition, in the stretching process, the unstretched yarn may be heat treated at a temperature of approximately 160-240 ° C., and preferably, may be heat-treated at a temperature of 160-180 ° C. for proper progress of the stretching process.

PET drawn yarn prepared by the above-described manufacturing method may exhibit a degree of crystallinity, birefringence, and the like according to another embodiment of the present invention, thereby, may exhibit a high shrinkage stress and modulus at the same time. Therefore, such PET stretch yarn can be applied to tire cords, and can be preferably used as a cap ply cord.

In accordance with another embodiment of the present invention, there is provided a PET tire cord including the PET stretch yarn described above.

These PET tire cords may have a L / S value of 70 g / d to 150 g / d, which is defined by the following Equation 1, thereby exhibiting better morphological stability:

[Equation 1]

L / S = LASE / Shrinkage (%)

In the above formula, LASE is a value defined as a load at a specific elongation (Load At Specific Elongation), in particular, in the above formula 1 is defined as a load at 3% elongation measured at 100 ℃. This is because the initial modulus of the PET tire cord is of great importance. In order to satisfy the above L / S value, the PET tire cord has a lase defined as a load at 3% elongation of 1.7 to 3.0 g when subjected to a tensile test under a supertension of 0.05 g / d and a temperature of 100 ° C. can be / d.

In Equation 1, the L / S value is a shape stability index indicating how stably the tire cord can be maintained despite the external heat or force. That is, as the L / S value is higher, the tire cord may be stably maintained without being deformed in spite of external heat or force. However, the PET tire cord according to another embodiment of the invention is manufactured with the above-described stretched yarn having high shrinkage stress and modulus, so that a very high L / S value, for example, L of 70 g / d to 150 g / d Since it has a value of / S, it is possible to effectively suppress the movement of the belt by wrapping the steel belt in the tire without being deformed well despite external heat or force. In addition, the PET tire cord can also effectively suppress the partial deformation and the noise caused by the tire and the vehicle's own load.

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

In addition, the PET tire cord has a strength of 5 to 8 g / d, 1.5 to 5.0%, preferably 2.0 to 5.0% of the core (elongation at 4.5kgf load), 10 to 25% of the elongation and 0.5 to 5.0%, Preferably it may exhibit a shrinkage (177 ℃, 30g, 2min) of 2.0 to 5.0%. 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.

And, the above-described PET tire cord can be applied as a cap ply cord of the pneumatic tire. The tire to which the PET tire cord is applied is not easily deformed due to its excellent shape stability of the cap ply cord, so that the tire itself is not easily deformed. Therefore, the tire can improve the controllability or ride comfort of the vehicle. In addition, since the PET tire cord effectively suppresses the movement of the steel belt and has various physical properties that can be preferably used as a capfly cord, the tire to which the capfly cord is applied can exhibit stable high-speed driving performance.

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

On the other hand, the tire cord of another embodiment of the present invention melt-spun PET to prepare a non-drawn yarn, stretch the non-drawn yarn to prepare a stretched yarn, after the twisted yarns are fused yarn and immersed in an adhesive to form a deep cord It can be prepared by a method for producing a tire cord of. The above-described PET tire cord may be manufactured by reflecting the specific conditions or the progressing methods of each step directly or indirectly in the physical properties of the final manufactured tire cord.

For example, PET non-drawn yarns, preferably one embodiment of the invention, that melt-spun PET under conditions of higher spinning tension and optionally high spinning speed, resulting in high crystallinity of 25% or higher and low amorphous orientation index of 0.15 or less By producing a PET non-stretched yarn, and by using this to prepare a PET stretched yarn and tire cord, PET tire cord of another embodiment of the invention can be provided. Thus, the PET tire cord of another embodiment of the invention can be prepared using another drawn yarn of PET in another embodiment, for example, a drawn yarn obtained from PET non-drawn yarn showing high crystallinity and low amorphous orientation index. Can be.

That is, the high degree of crystallinity and low amorphous orientation index of the PET non-drawn yarn, it is possible to manufacture a PET drawn yarn showing a low shrinkage rate with a high shrinkage stress, PET PET having excellent shape stability, etc. suitable for the cap ply cord, etc. using this Code can be prepared.

In addition, in the manufacturing process of the PET tire cord, the step of pulverizing the PET stretched yarn and immersed in the adhesive may be in accordance with the manufacturing process conditions and methods of conventional PET tire cord.

According to the present invention, there are provided PET non-drawn yarns and stretched yarns exhibiting advanced crystal structure and excellent orientation properties, and PET tire cords obtained using the same.

The PET tire cord exhibits excellent modulus and shape stability, while suppressing rattling and noise while driving a vehicle, and exhibits high shrinkage stress, thereby effectively suppressing the movement of the steel belt in the tire.

Therefore, this PET tire cord can be used very preferably as a tire cord for cap ply of pneumatic tires.

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]

Examples 1 to 6 (Preparation of PET Unstretched)

PET unstretched yarns of Examples 1 to 6 were prepared by melt spinning and cooling a PET polymer having a predetermined intrinsic viscosity. At this time, the intrinsic viscosity of the PET polymer, the spinning speed and the spinning tension conditions in the melt spinning process are as shown in Table 1, the remaining conditions were in accordance with conventional conditions for the production of PET non-drawn yarn.

[Table 1]

Example One 2 3 4 5 6 Intrinsic Viscosity (dl / g) 0.85 1.05 1.05 1.05 1.05 1.20 Spinning speed (m / min) 4200 3800 4000 4200 4500 4200 Radial tension (g / d) 0.93 0.86 0.92 1.03 1.15 1.08

The physical properties of the non-drawn yarns prepared according to Examples 1 to 6 were measured by the following methods, and the measured physical properties 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.)

Birefringence: The birefringence was measured using a polarizing microscope.

-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)

-Dry heat shrinkage: The dry heat shrinkage was measured for 2 minutes at 180 ° C. temperature and ultra high tension (30 g) using Testrite MK-V of Testrite of England.

Strength, Strength at 1% Elongation, LASE Value, and Body Weight: The strength, strength at 1% elongation, LASE, and body weight were measured using a universal tensile tester according to ASTM D885 criteria.

Melting Point and Specific Heat of Determination (ΔH): A DSC-7 instrument was applied, and the melting point and the specific heat of crystal were measured by chopping the yarn (undrawn or drawn yarn) into approximately 2 mg samples. At this time, the temperature was applied to a temperature increase rate of 20 ℃ / min.

Plane spacing: Plane spacing was measured using XRD.

[Table 2]

Example One 2 3 4 5 6 Crystallinity (%) 32 28 30 33 36 33 Birefringence 0.090 0.088 0.090 0.091 0.093 0.092 AOF 0.074 0.120 0.093 0.054 0.009 0.061 Strength (g / d) 3.7 3.7 3.9 4.0 4.1 4.0 Dry heat shrinkage (%) 5.2 6.2 5.7 5.5 4.6 5.9 Strength at 1% Elongation (g / d) 0.567 0.481 0.532 0.571 0.613 0.584 Melting point (캜) 262 258 263 262 270 261 010 face spacing 53 51 52 53 55 52 110 spaces 48 45 46 47 48 45 100 face spacing 46 42 43 45 47 43

Comparative Examples 1 to 6 (manufactured by PET undrawn)

A PET non-drawn yarn of Comparative Examples 1 to 6 was prepared according to the same method as Examples 1 to 6 except for the conditions described in Table 3 below.

[Table 3]

Comparative example One 2 3 4 5 6 Intrinsic Viscosity (dl / g) 0.75 1.05 1.05 1.05 1.05 1.30 Spinning speed (m / min) 4200 3000 3500 3800 5000 4200 Radial tension (g / d) 0.81 0.52 0.63 0.72 Cannot be sacrificed Cannot be sacrificed

Except for the non-preparable Comparative Examples 5 and 6, the physical properties of the undrawn yarn prepared according to Comparative Examples 1 to 4 are summarized in Table 4 below.

[Table 4]

Comparative example One 2 3 4 Crystallinity (%) 24 9 12 22 Birefringence 0.087 0.072 0.080 0.085 AOF 0.157 0.245 0.255 0.168 Strength (g / d) 3.2 2.8 3.0 3.2 Dry heat shrinkage (%) 5.0 12.3 11.6 7.3 Strength at 1% Elongation (g / d) 0.423 0.152 0.165 0.337 Melting point (캜) 257 254 254 255 010 face spacing 50 46 47 48 110 spaces 43 41 42 42 100 face spacing 42 32 36 38

As shown in Tables 2 and 4, the unstretched yarns of Examples 1 to 6 prepared under high spinning tension and spinning speed have high crystallinity and low amorphous orientation index, and exhibit advanced crystal structure and excellent orientation characteristics. It was confirmed that the undrawn yarns of Comparative Examples 1 to 4 did not satisfy these characteristics.

Examples 7 to 12 (Preparation of PET Stretch Yarn)

The PET drawn yarns of Examples 7 to 12 were prepared by stretching the undrawn yarns prepared according to Examples 1 to 6 at a draw ratio as shown in Table 5 and then heat-treating at 180 ° C. The physical properties of the PET stretched yarn were measured by the same method as the undrawn yarn, and are shown in Table 5 below.

[Table 5]

Example 7 8 9 10 11 12 Unpainted Shrine Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Stretching cost 1.39 1.54 1.46 1.39 1.30 1.39 Crystallinity (%) 42 40 41 42 45 41 Birefringence 0.139 0.150 0.147 0.137 0.128 0.141 AOF 0.236 0.348 0.312 0.220 0.093 0.267 Strength (g / d) 6.0 7.0 6.7 6.3 6.0 6.4 Dry heat shrinkage (%) 6.5 8.3 8.0 6.3 5.8 7.4 Strength at 1% Elongation (g / d) 0.92 0.82 0.90 0.98 1.03 0.93 Majority (%) 5.5 5.2 5.4 5.7 5.9 5.6 010 face spacing 54 49 52 53 55 52 110 spaces 44 42 43 44 45 44 100 face spacing 43 38 40 43 45 41

Comparative Examples 7 to 10 (manufacture of PET stretcher)

PET stretched yarns of Comparative Examples 7 to 10 were prepared in the same manner as in Examples 7 to 12, except that the non-drawn yarns prepared according to Comparative Examples 1 to 4 were used. The physical properties of the PET stretched yarn were measured in the same manner, and are shown in Table 6 below.

TABLE 6

Comparative example 7 8 9 10 Unpainted Shrine Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Stretching cost 1.39 1.8 1.57 1.50 Crystallinity (%) 38 35 36 37 Birefringence 0.163 0.184 0.180 0.171 AOF 0.472 0.651 0.615 0.541 Strength (g / d) 5.4 7.8 7.6 7.2 Dry heat shrinkage (%) 9.2 12.5 11.7 10.2 Strength at 1% Elongation (g / d) 0.545 0.442 0.473 0.523 Majority (%) 7.4 5.4 5.5 5.9 010 face spacing 48 44 46 47 110 spaces 41 40 41 41 100 face spacing 38 32 32 37

As shown in Tables 5 and 6, as shown in Tables 5 and 6, PET stretched yarns according to Examples 7 to 12 obtained from the non-drawn yarns of Examples 1 to 6 have high crystallinity, high birefringence, and low AOF. The dry heat shrinkage was low and the strength at 1% elongation was high. In contrast, it was confirmed that the PET stretched yarns of Comparative Examples 7 to 10 obtained from the non-stretched yarns of Comparative Examples 1 to 4 did not satisfy these characteristics.

Examples 13-18 (Preparation of Tire Cords)

To produce a tire cord with the drawn yarns prepared according to Examples 7 to 12, the twisted yarns are blended under conditions of upper and lower 430 TPM and lower and lower 430 TPM, immersed in an RFL adhesive solution, and then dried and heat-treated to form a deep cord for cap ply. Was prepared. At this time, the drawer was 1000De 'yarn and was assigned 430TPM based on this.

Comparative Examples 11 to 14 (Production of Tire Cords)

In order to manufacture the tire cord with the drawn yarn prepared according to Comparative Examples 7 to 10, the twisted yarns are blended under the conditions of the upper edge 430 TPM and the lower edge 430 TPM, and immersed in the RFL adhesive solution, followed by drying and heat treatment. Was prepared.

The L / S values of the tire cords prepared according to Examples 13 to 18 and Comparative Examples 11 to 14 and LASE values at 3% elongation measured at 100 ° C. under supertension of 0.05 g / d are shown in Table 7 below. .

[Table 7]

Used drawer L / S (g / d) 3% elongation LASE (g / d) Example 13 Example 7 84 1.80 Example 14 Example 8 71 1.95 Example 15 Example 9 70 1.90 Example 16 Example 10 81 1.85 Example 17 Example 11 94 2.10 Example 18 Example 12 73 1.90 Comparative Example 11 Comparative Example 7 68 1.60 Comparative Example 12 Comparative Example 8 55 1.30 Comparative Example 13 Comparative Example 9 64 1.45 Comparative Example 14 Comparative Example 10 67 1.50

As shown in Table 7, the tire cords prepared from the drawn yarns prepared from Examples 16 to 21 and having high crystallinity, etc., have L / S values of 70 to 150 g / d, and the tires are actually used. Since the LASE value was 1.7 to 3.0 g / d even at 100 ° C., it was found to be excellent in form stability and to be used as a tire cord for cap ply. In contrast, it was confirmed that the tire cords of Comparative Examples 12 to 15 did not satisfy these characteristics.

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

Claims (18)

A polyethylene terephthalate undrawn yarn having a degree of crystallinity of 25% or more, a birefringence of 0.085 to 0.11, an amorphous orientation index (AOF) of 0.15 or less, and a melting point (Tm) of 258 ° C or more. The polyethylene terephthalate undrawn yarn according to claim 1, wherein the crystallinity is 25 to 40%. The polyethylene according to claim 1, wherein the (010) plane spacing of the crystals calculated from the XRD measurement peak is 51 to 57 GPa, the (110) plane spacing is 45 to 50 GPa, and the (100) plane spacing is 42 to 50 GPa. Terephthalate undrawn. Polyethylene terephthalate stretched yarn containing 90 mol% or more of polyethylene terephthalate, crystallinity of 40% or more, and birefringence of 0.12 to 0.16. The polyethylene terephthalate stretched yarn according to claim 4, wherein the crystallinity is 40 to 50%. The polyethylene terephthalate stretched yarn according to claim 4, wherein the amorphous orientation index (AOF) is 0.35 or less. The polyethylene terephthalate stretched yarn according to claim 6, wherein the amorphous orientation index is 0.01 to 0.2. The polyethylene according to claim 4, wherein the (010) plane spacing of the crystals calculated from the XRD measurement peak is 48 to 60 mm 3, the (110) plane interval is 42 to 50 mm 3, and the (100) plane interval is 38 to 50 mm 3. Terephthalate drawn yarn. Melting and spinning a polymer including 90 mol% or more of polyethylene terephthalate to prepare polyethylene terephthalate undrawn yarn having a crystallinity of 25% or more and an amorphous orientation index of 0.15 or less; And A method for producing polyethylene terephthalate stretched yarn comprising stretching the polyethylene terephthalate non-stretched yarn to produce polyethylene terephthalate stretched yarn under a draw ratio of 1.0 to 1.55. The method according to claim 9, wherein the polyethylene terephthalate undrawn yarn has a birefringence of 0.085 to 0.11 and a melting point (Tm) of 258 ° C or higher. Polyethylene terephthalate tire cord comprising the stretched yarn according to any one of claims 4 to 8. The polyethylene terephthalate tire cord according to claim 11, wherein the L / S value defined by the following formula 1 is 70 g / d to 150 g / d: [Equation 1] L / S = LASE / Shrinkage (%) In the above formula, LASE is defined as Load At Specific Elongation measured at 100 ° C. 12. The polyethylene terephthalate tire cord according to claim 11, wherein LASE is defined as a load at 3% elongation of 1.7 to 3.0 g / d when subjected to tensile strength under a tensile strength of 0.05 g / d and a temperature of 100 ° C. 12. The polyethylene terephthalate tire cord of claim 11 having a strength of 5 to 8 g / d, a torsion of 1.5 to 5.0% (@ 4.5 kgf) and a stretch of 10 to 25%. 12. Polyethylene terephthalate tire cord according to claim 11, wherein the total fineness is 1000 to 5000 denier, 1 to 3 plies and 200 to 500 TPM. The polyethylene terephthalate tire cord according to claim 11, which is a capfly cord. A pneumatic tire comprising the tire cord according to claim 11. 18. The pneumatic tire according to claim 17, wherein said cord is applied to a cap ply.

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