KR20180078489A - Hybrid Tire Cord for Carcass and Method for Manufacturing The Same - Google Patents

Abstract

Disclosed are a hybrid tire cord capable of realizing high performance and lightweight of a tire based on high strength, high modulus, and high fatigue resistance properties, and a method for manufacturing the same. The hybrid tire cord of the present invention includes: a PET primarily-twisted yarn manufactured from PET filament yarn of 1500 to 3000 denier; an aramid primarily-twisted yarn manufactured from aramid filament yarn of 1500 to 3000 denier; and an adhesive coated on the PET primarily-twisted yarn and the aramid primarily-twisted yarn. The PET single yarn and the aramid single yarn are stitched together. In the hybrid tire cord for carcass having a predetermined length, the length of the aramid primarily-twisted yarn is 1 to 1.1 times the length of the PET primarily-twisted yarn, after the secondary twist is untwisted.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a hybrid tire cord for a carcass,

The present invention relates to a hybrid tire cord for carcass and a manufacturing method thereof, and more particularly to a hybrid tire for carcass which can realize high performance and light weight by having high strength, high modulus, Code and a method of manufacturing the same.

Background Art [0002] As a reinforcing material for rubber products such as tires, conveyor belts, V-belts, hoses and the like, fiber cords, in particular, fiber cords treated with adhesives (so-called "dip cords") have been widely used. The material of the fiber cord includes nylon fiber, polyester fiber, and rayon fiber. One of the important ways to improve the performance of finished rubber products is to improve the properties of the fiber cords used as reinforcements.

The fiber cord used as a reinforcing material of a tire is referred to as a tire cord. The driving speed of the vehicle is gradually increasing due to the improvement of the car performance and the improvement of the road condition. Therefore, studies on the tire cord that can maintain the stability and durability of the tire at high speeds are being actively conducted.

In addition, as the demand for environmentally friendly vehicles increases, weight reduction of vehicles for high fuel consumption is becoming a big issue, and research on light weight of tires has also been actively conducted.

A tire, which is a composite of fibers / metal / rubber, comprises a tread that is located at an outermost position and contacts the road surface, a cap ply under the tread, a belt under the cap fly, And carcass.

Since the carcass has a structure for supporting the load of the vehicle body and covering the entire surface of the tire as a skeleton of the tire for maintaining the air pressure of the tire, weight reduction of the carcass is required for reducing the weight of the tire. In order to reduce the weight of the carcass, it is necessary to reduce the number of the carcass reinforcing material layers or reduce the thickness of each reinforcing material layer. For this purpose, high performance of the tire cord for carcass must be determined.

Currently, PET (polyethylene terephthalate) and rayon (Rayon) are mainly used as materials for carcass tire cords, but both of them are strong enough to reduce the number of carcass reinforcement layers or reduce the thickness of each reinforcement layer. And insufficient modulus.

On the other hand, hybrid tire cords made of nylon and aramid have been developed using cap blades. The hybrid tire cords are characterized in that the nylon properties are initially expressed on the S-S curve pattern and exhibit low modulus. Since the carcass acts as a whole skeleton of the tire and has a great influence on the shape stability of the tire, there is a problem that when the initial modulus is low, the shape of the tire is collapsed due to low shape stability in manufacturing the tire. That is, the hybrid tire cord of nylon and aramid is recognized as not suitable for carcass.

Particularly, as the demand for SUV (Sport Utility Vehicle) and LT (Light Truck) increases, it is suitable for a high-pressure tire that can withstand a load higher than that of a tire of a general vehicle and can secure driving stability (that is, ) High-strength and high-modulus tire cords are further demanded.

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a hybrid tire cord for carcass and a method of manufacturing the same, which can prevent problems due to limitations and disadvantages of the related art.

One aspect of the present invention is to provide a hybrid tire cord for carcass which can realize high performance and light weight of a tire by having high strength, high modulus, and excellent endurance characteristics.

Another aspect of the present invention is to provide a hybrid tire cord for carcass that can realize high performance and light weight of a tire by having high strength, high modulus, and excellent endurance characteristics, and can be manufactured with high productivity and low cost while minimizing physical property variations It is a way to be able to do.

Other features and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description. Alternatively, other features and advantages of the present invention may be understood through practice of the present invention. Objects and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims of this invention.

According to one aspect of the present invention, there is provided a hybrid tire cord for carcass, comprising: a PET single yarn produced from a PET filament yarn of 1500 to 3000 denier; Aramid yarn produced from aramid filament yarn of 1500 to 3000 denier; And an adhesive coated on the aramid monofilament, wherein the PET monofilament and the aramid monofilament stand together and unt twist the outer surface of the hybrid tire cord for carcass of a predetermined length and measure Wherein the length of the aramid single yarn is 1 to 1.1 times the length of the PET single yarn.

The PET single yarn and the aramid single yarn may each have a first twist number.

The PET single yarn and the aramid single yarn are stacked together in a second twist number, and the second twist number may be equal to the first twist number.

The weight ratio of the PET yarn and the aramid yarn may be 1: 3 to 3: 1.

The strength, 3% LASE, 5% LASE, and 7% LASE of the hybrid tire cord for carcass as measured by ASTM D885 may be greater than 30 kgf, greater than 8 kgf, greater than 15 kgf, and greater than 25 kgf, respectively.

The breaking strength and elongation at break of the hybrid tire cord for carcass measured by ASTM D885 may be 10.0 to 15.0 g / d and 8 to 15%, respectively.

The strength retention ratio of the hybrid tire cord for carcass after the disk fatigue test conducted in accordance with JIS-L 1017 may be 80% or more.

According to another aspect of the present invention, there is provided a method for producing an aramid single yarn, comprising: a first step of dipping an aramid filament yarn of 1500 to 3000 denier in a first direction to form an aramid single yarn; A second step of lowering the PET filament yarn of 1500 to 3000 denier in the first direction to form a PET single yarn; A third step of straddling the aramid single yarn and the PET single yarn together in a second direction to form a combined twist yarn; Immersing the combined yarn in an adhesive solution; Drying the composite yarn impregnated with the adhesive solution; And heat treating the dried composite yarn, wherein the second direction is the opposite direction of the first direction, and the length of the PET single yarn measured after untwisting the upper edge with respect to the composite yarn of a predetermined length The tension applied to the PET filament in the second step is smaller than the tension applied to the aramid filament in the first step by an amount which is in the range of 1.005 to 1.05 times the length of the aramid single yarn, A method of manufacturing a cord is provided.

The first, second, and third steps may be performed by one twister.

The adhesive solution may include an RFL (Resorcinol Formaldehyde Latex) adhesive or an epoxy adhesive, and the drying step may be performed at 70 to 200 ° C for 30 to 120 seconds, and the heat treatment step may be performed at 30 to 250 ° C To 120 seconds, and the immersion step, the drying step, and the heat treatment step may be continuously performed.

The tension applied to the combined yarn in the immersion, drying, and heat treatment steps may be 0.4 kg / cord or more.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the invention as claimed.

According to the present invention, since the process of manufacturing a filament yarn single yarn and the process of manufacturing a twist yarn with two or more single yarns are performed by one twister, the productivity of the hybrid tire cord can be improved and the manufacturing cost can be reduced.

In addition, the hybrid tire cord of the present invention can minimize tire deformation during high-speed travel, and is particularly suited to a carcass of a high-pressure tire that must withstand high loads such as SUVs, LTs, etc., .

Also, according to the present invention, it is possible to minimize the strength and modulus deterioration which may be caused in the manufacturing process of the hybrid tire cord, in particular, the heat treatment process.

Further, according to the present invention, stress applied to the tire cord when the tension / compression of the tire is repeated can be dispersed not only in the aramid single yarn but also in the PET single yarn. As a result, the hybrid tire cord of the present invention having excellent endurance characteristics can maintain the stability of the tire even at high speed traveling for a long time.

Hereinafter, embodiments of the hybrid tire cord for carcass of the present invention and its manufacturing method will be described in detail.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Therefore, the present invention encompasses all changes and modifications that come within the scope of the invention as defined in the appended claims and equivalents thereof.

As used herein, the term "single yarn" means a yarn formed by twisting a single filament yarn in one direction.

The term " cabled yarn " as used herein means a yarn formed by twisting two or more single yarns together in one direction, and may be referred to as a " raw cord ".

The term "tire cord" as used herein refers to a composite yarn coated with an adhesive so that it can be directly applied to a rubber product, and may also be referred to as a "dip cord ".

As used herein, the term "twist number" means the number of twists per meter, and the unit is a twist per meter (TPM).

As used herein, " LASE " means load at specific elongation, for example 3% LASE means load at 3% elongation.

Since the carcass to which the tire cord of the present invention is applied is intended to maintain the shape of the tire and to improve the running performance of the car, the tire cord for carcass is preferably made of the material properties of the material itself and the linear density, And so on.

The tire cord according to the present invention is a hybrid type of PET and aramid, which comprises a PET single yarn and an aramid single yarn, wherein the PET single yarn and the aramid single yarn are stitched together.

The PET filament yarn and the aramid filament yarn are simultaneously inferred by a single twist yarn (for example, Allma's Cable Corder) so that the PET yarn and the aramid yarn are formed, and at the same time (that is, continuously) Aramid single yarn is performed together to form a composite yarn.

The PET yarn and the aramid yarn have the same twist direction and can have the same twist number, e.g., a first twist number of 200 to 500 TPM, respectively.

The PET single yarn and the aramid single yarn are stacked together in a second twist number, and the second twist number may be equal to the first twist number. The upstanding direction is opposite to the twist direction of the single yarns.

According to the present invention, since the lower edge and the upper edge are performed by one twister, it is possible to improve the productivity of the hybrid tire cord and reduce the manufacturing cost compared to the batch type method in which each lower edge and the upper edge are performed by using different twists have.

On the other hand, aramid has a linear molecular chain and therefore has a high degree of crystallinity and little heat shrinkage behavior. On the other hand, the PET filament yarn manufactured through the stretching process to develop the high strength and high modulus required in the tire cord is shrunk during the heat treatment process performed in the dip cord manufacturing process, and as a result, the length of the aramid single yarn Is greater than 1.1 times the length of the PET monofilament, the tensile strength and modulus of the tire cord are lowered, and the endothelial property is also decreased.

Therefore, according to the present invention, in order to produce a hybrid tire cord for carcass having high strength, high modulus and excellent endothelial property, the tension applied to the aramid filament yarn and the PET filament yarn is adjusted during the twisting process, It is made longer than the aramid single yarn. In addition, a relatively high level of tension (for example, 0.4 kg / cord) or more can be applied to the composite yarn (cord) in order to minimize shrinkage of the PET yarn during the heat treatment process.

Specifically, the tension applied to the aramid filaments and the PET filaments during the twisting process is appropriately adjusted so that the aramid yarn and the PET yarn have substantially the same length and structure in the final tire cord. That is, when the lower edge and the upper edge are performed, the length of the PET single yarn can be made longer than that of the aramid single yarn by applying a relatively larger tension to the aramid filament yarn than the PET filament yarn.

According to the present invention, the length of the PET monofilament measured after untwisting the upper edge with respect to the sum yarn (rope cord) of a predetermined length is 1.005 to 1.05 times the length of the aramid single yarn. That is, the composite yarn (rocod) of the present invention has a merged structure in which the aramid single yarn covers the structure of the PET yarn (i.e., the " covering structure ").

Since the length of the PET single yarn is longer than the length of the aramid single yarn in the composite yarn (roc cord) of the present invention, due to shrinkage of the PET single yarn caused when the subsequent dipping, drying and heat treatment steps for imparting an adhesive are sequentially performed The length of the aramid single yarn in the final tire cord (i.e., dipped cord) can be prevented from becoming excessively longer than that of the PET single yarn. According to a preferred embodiment of the present invention, the length of the aramid single yarn measured after untwisting the upper edge with respect to the final tire cord of a predetermined length is 1 to 1.1 times the length of the PET single yarn.

If the aramid yarn in the tire cord is shorter than the PET yarn (that is, the length of the PET yarn in the combined yarn exceeds 1.05 times the length of the aramid yarn), the stress applied to the tire cord Is intensively applied to the aramid single yarn, the endurance characteristics of the tire cord are inevitably low, and the stability of the tire can not be secured at the time of high-speed traveling for a long time due to such low endothelial characteristics.

On the other hand, when the length of the PET single yarn is less than 1.005 times the length of the aramid single yarn, the tire cord of the covering structure in which the length of the aramid single yarn exceeds 1.1 times the length of the PET single yarn is finally obtained. In the tire cord having such a covering structure, since the aramid single yarn covering the PET single yarn is pushed by the friction with the guide or the roller to form a loop, the unevenness of the shape is caused, In the tire manufacturing process, the defective tire ratio increases due to the physical property variation.

According to the present invention, the same twist number is applied within the range of 200 to 500 TPM when performing the bottom edge and top edge for the combined twist yarn (roc cord). However, unexpected untwist occurs when the subsequent dipping, drying, and heat treatment processes for applying the adhesive are performed sequentially, resulting in a difference of less than 15% between the initial set twist count and the initial set twist count have. Generally, the higher the twist of the filament yarn, the lower the strength but the higher the fatigue performance. On the other hand, the lower the twist of the filament yarn, the stronger the strength, but the fatigue performance decreases.

According to the present invention, the aramid yarns and PET yarns exhibit similar behavior in strength and fatigue performance as they have substantially the same twist number, length and structure in the final tire cord.

The aramid filament yarn and the PET filament yarn used for producing the hybrid tire cord of the present invention are not particularly limited, but have the same or similar fineness within a range of 1500 to 3000 denier.

The aramid contains an amide group and a phenyl ring in the main chain, and is classified into a para-form (p-) and a meta-form (m-) depending on the linkage state of the phenyl ring. According to a preferred embodiment of the present invention, the aramid is poly (p-phenylene terephthalamide).

According to one embodiment of the present invention, the aramid filament yarn has a fineness of 1500 to 3000 denier, a tensile strength of 20 g / d or more, and a cut elongation of 3% or more. If the tensile strength of the aramid filament yarn is less than 20 g / d, the low strength of the PET filament yarn can not be sufficiently compensated, thereby increasing the risk of tire deformation at high speed.

Aramid filament yarn has a modulus of 5 to 10 times higher than that of PET filament yarn, so that even if the weight ratio of aramid single yarn to PET single yarn is only about 15:85 in hybrid tire cord, the aramid filament yarn has a modulus of 2 to 3 times the tire cord of PET single yarn. Therefore, the weight ratio of the aramid single yarn and the PET single yarn can be determined by considering both the physical properties of the tire cord and the manufacturing cost. According to one embodiment of the present invention, the weight ratio of the aramid yarn to the PET yarn is 1: 3 to 3: 1.

If the weight of the PET single yarn exceeds 3 times the weight of the aramid single yarn, the finally obtained hybrid tire cord follows the physical properties of the PET, resulting in insufficient strength and modulus, and is not suitable as a tire cord for high-pressure tire requiring high form stability . Also, since a large number of carcass layers must be used to make up for the insufficient strength and modulus, the weight of the tire can not be reduced.

On the other hand, when the weight of the aramid single yarn is more than three times the weight of the PET single yarn, the performance of the hybrid tire cord is deteriorated by the inner film of the hybrid tire cord, so that it is difficult to secure the durability of the tire and cost increases by using a large amount of expensive aramid.

The hybrid tire cord of the present invention further includes the PET single yarn and an adhesive coated on the aramid single yarn to improve the adhesive strength with other structures of the tire. The adhesive may be an RFL (Resorcinol Formaldehyde Latex) adhesive or an epoxy adhesive.

The hybrid tire cord of the present invention has a high strength and strength of 30 kgf or more. In addition, the hybrid tire cord of the present invention has a high modulus, i.e., 3% LASE of 8 kgf or more, 5% LASE of 15 kgf or more, and 7% LASE of 25 kgf or more, . Further, the breaking strength and elongation at break of the hybrid tire cord for carcass of the present invention may be 10.0 to 15.0 g / d and 8 to 15%, respectively. The strength, breaking strength, elongation at break, 3% LASE, 5% LASE, and 7% LASE of the tire cord are the values measured by ASTM D885, respectively.

The hybrid tire cord of the present invention may have a strength retention ratio of 80% or more after the disk fatigue test according to JIS-L 1017.

Hereinafter, the method of manufacturing the hybrid tire cord of the present invention will be described in more detail.

An aramid filament yarn of 1500 to 3000 denier and a PET filament yarn of 1500 to 3000 denier are fed into a cable cord twisting machine (for example, Allma's Cable Corder) which performs both the lower and upper yarns. In the twisting machine, a first step of lowering the aramid filament yarn in the first direction to form the aramid yarn and a second step of lowering the PET filament yarn in the first direction to form the PET yarn are simultaneously performed, A third step of straddling the aramid yarn and the PET yarn together in a second direction to form a continuous yarn is continuously performed with the first and second steps.

As described above, the second direction is opposite to the first direction, and the same twist number is applied within the range of 200 to 500 TPM when performing the upper edge with the lower edge.

According to the present invention, since the combined yarn is produced by the continuous method in which the lower and upper yarns are performed in one twisted yarn, the PET filament yarn and the aramid filament yarn are respectively twisted with different twisted yarns and then bundled with another twisted yarn The productivity of the hybrid tire cord can be improved as compared with the method of the present invention.

According to the present invention, the tension applied to the PET filament in the second step is smaller than the tension applied to the aramid filament in the first step. Therefore, the length of the aramid single yarn measured after untwisting the upper edge with respect to the combined yarn (rope cord) of a predetermined length is shorter than the length of the PET single yarn, even though the lower yarn and the upper yarn are performed by one twister.

According to an embodiment of the present invention, the length of the PET single yarn measured after untwisting the upper edge with respect to the combined yarn (roving cord) of a predetermined length is increased by 1.005 to 1.05 times the length of the aramid single yarn, The tension applied to the PET filament yarns in the second step is smaller than the tension applied to the aramid filament yarns in the first step.

The magnitude of the tension applied to the PET filament yarn and the aramid filament yarn can be adjusted by appropriately setting the 'Creel Yarn Tension' and the 'Inner Yarn Tension' of the twin screw extruder.

Subsequently, a step of immersing the combined yarn (roving cord) in an adhesive solution, a step of drying the combined yarn (roving cord) impregnated with the adhesive solution, and a step of heat treating the dried roving yarn The hybrid tire cord of the present invention (i.e., a deep code) is completed.

An RFL solution (Resorcinol Formaldehyde Latex) or an epoxy based adhesive composition liquid may be used as the adhesive solution.

The temperature and time of the drying step may vary depending on the composition of the adhesive solution, but the drying step is usually carried out at 70 to 200 DEG C for 30 to 120 seconds.

The heat treatment may be performed at 200 to 250 ° C for 30 to 120 seconds.

Through the above-described processes, the adhesive component of the adhesive solution is coated on the surface of the composite yarn (roving cord), so that the adhesion between the hybrid tire cord of the present invention and other components of the tire is increased.

On the other hand, although the twisted yarn is set to perform the lower and upper yarns with the same twist number, twist loosening may occur during the process of being dipped in the adhesive solution, dried and heat-treated after the twist yarn (roving cord) produced by the twist yarn machine. In order to minimize such twist loosening (for example, to ensure that the difference between the original set twist count and the actual twist count of the final tire cord is less than 15% of the original set twist count) and to prevent excessive shrinkage of the PET yarn , It is preferable that the tensile force applied to the combined yarn (roving cord) in the immersion, drying, and heat treatment steps performed continuously is 0.4 kg / cord or more.

According to the present invention, it is possible to remarkably reduce the twist failure in the twisting process and to stabilize the combined yarn, so that the variation in physical properties due to unevenness in shape can be minimized. Specifically, in the case of the hybrid tire cords of the present invention manufactured under the same conditions, the difference between the maximum value and the minimum value in each property can be drastically reduced,

Hereinafter, the effects of the present invention will be described with reference to specific examples and comparative examples of the present invention. It should be understood, however, that the following examples are for the purpose of promoting understanding of the present invention and are not intended to limit the scope of the present invention.

Example  One

1500 denier PET filament yarn and 1500 denier aramid filament yarn were fed into a cable cord twisted cable machine (Allma's Cable Corder), and the Z-direction bottom wire and the S- -ply cabled yarn (code). At this time, the cable cord twisted yarn was set at a twist number of 380 TPM for the lower yarn and the upper yarn, and the tension applied to the PET filament yarn and the aramid filament yarn was adjusted so that the aramid yarn length (Length of PET single strand / length of aramid single strand: L _P / L _A ) was set to 1.03. In order to obtain the length ratio between the aramid single yarn and the PET single yarn, a single yarn of 1 m long yarn (cord) was subjected to a 0.05 g / d load to separate the aramid single yarn and PET single yarn, The lengths of the PET monofilaments were measured under the conditions of a load of 0.05 g / d.

The combined twist yarn (lo cord) was then kneaded with 2.0 wt% resorcinol, 3.2 wt% formalin (37%), 1.1 wt% sodium hydroxide (10%), 43.9 wt% styrene / butadiene / vinyl pyridine 15/70/15) rubber (41%), and water. The resulting solution was dipped in a resorcinol-formaldehyde-latex (RFL) adhesive solution. The hybrid tire cord was completed by drying the composite yarn (roc cord) containing the RFL solution by dipping at 150 DEG C for 100 seconds and then heat-treating at 240 DEG C for 100 seconds. The tensile force applied to the composite yarn during the immersion, drying, and heat treatment was 0.5 kg / cord.

Example  2

2000 denier PET filament yarn was used instead of 1500 denier PET filament yarn and 2000 denier aramid filament yarn was used instead of 1500 denier aramid filament yarn. The hybrid tire cord was completed in the same manner as in Example 1, except that it was set.

Example  3

_A hybrid tire cord was prepared in the same manner as in Example 1, except that the ratio (L _P / L _A ) of the length of the PET monofilament to the aramid monofilament length in the combined yarn (roc cord) was 1.005.

Example  4

_A hybrid tire cord was prepared in the same manner as in Example 1, except that the ratio (L _P / L _A ) of the length of the PET monofilament to the length of the aramid monofilament in the combined twist yarn (rope cord) was 1.05.

Comparative Example  One

1000 denier PET filament yarn was used instead of 1500 denier PET filament yarn and 1000 denier aramid filament yarn was used instead of 1500 denier aramid filament yarn. The hybrid tire cord was completed in the same manner as in Example 1, except that it was set.

Comparative Example  2

A hybrid tire cord was completed in the same manner as in Comparative Example 1, except that the cable cord twisted yarn was set at a twist number of 460 TPM for the lower run.

Comparative Example  3

_A hybrid tire cord was prepared in the same manner as in Example 1, except that the ratio (L _P / L _A ) of the length of the PET monofilament to the length of the aramid monofilament in the combined twist yarn (cord) was 1.003.

Comparative Example  4

_A hybrid tire cord was prepared in the same manner as in Example 1 except that the ratio (L _P / L _A ) of the length of the PET monofilament to the length of the aramid monofilament in the combined twist yarn (cord) was 1.052.

(I) the ratio of aramid single yarn length to aramid single yarn length (aramid yarn length / PET yarn length: L _A / L _P ) of the hybrid tire cords obtained by the above Examples and Comparative Examples, (ii) (iii) 3% LASE, (iv) 5% LASE, (v) 7% LASE, and (vi) disc fatigue test were measured by the following methods. The results are shown in Table 1.

* PET cinnabar  For length Aramid cinnabar  Length ratio (L _A / L _P )

The length of the aramid single yarn and the length of the PET single yarn were 0.05 g / d under a load of 0.05 g / d. The aramid single yarn and the PET single yarn were separated from each other by applying a load of 0.05 g / d to a 1 m long hybrid tire cord sample. Respectively.

* strong( kgf ), 3% LASE ( kgf ), 5% LASE ( kgf ), 7% LASE ( kgf )

According to the ASTM D-885 test method, tensile strength at 300 m / min was applied to 10 samples of 250 mm using an Instron tester (Instron Engineering Corp., Canton, Mass) LASE, 5% LASE, and 7% LASE, respectively. Next, the strength of the hybrid tire cord, 3% LASE, 5% LASE, and 7% LASE were obtained by calculating the average values of strength, 3% LASE, 5% LASE and 7% LASE of 10 samples respectively.

* Strong retention after disk fatigue test ( % )

After the hybrid tire cords were vulcanized to produce a sample, the disk fatigue tester was measured according to JIS-L 1017 method of Japanese Standard Association (JSA) The sample was subjected to fatigue by repeating tensile and shrinkage for 16 hours within a range of +/- 8% while rotating at a speed of 80 to 2500 rpm. Then, after the rubber was removed from the sample, the fatigue strength of the hybrid tire cord was measured. Based on the fatigue pre-stress and post-fatigue strength, the strength retention rate defined by the following formula 1 was calculated.

(1): Strength retention (%) = [Strength after fatigue (kgf) / Strength before fatigue (kgf)] × 100

Here, the pre-fatigue and post-fatigue strength (kgf) was measured at a tensile rate of 300 m / min for a 250 mm sample using an Instron tester (Instron Engineering Corp., Canton, Mass) according to the ASTM D- And the strength of the hybrid tire cord was measured.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 synthesis
year
four PET yarn
Line density
(denier) 1500 2000 1500 1500 1000 1000 1500 1500 Aramid
Single yarn density
(denier) 1500 2000 1500 1500 1000 1000 1500 1500 Twist Count (TPM) 380 300 380 380 360 460 380 380 L _P / L _A 1.03 1.03 1.005 1.05 1.03 1.03 1.003 1.052 Get
this
uh

nose
De L _A / L _P 1.02 1.025 1.035 1.00 1.015 1.03 1.05 1.00 Strong (kgf) 38.4 45.1 37.2 38.3 25.2 24.2 22.6 25.1 3% LASE
(kgf) 10.7 14.9 9.3 12.1 7.6 7.3 6.9 7.5 5% LASE
(kgf) 17.8 23.6 16.6 19.3 14.8 14.1 13.4 14.8 7% LASE
(kgf) 27.6 35.4 26.1 28.7 23.7 22.1 21.7 23.6 strong
Retention rate (%) 85.6 86.4 81.4 80.2 68.8 91.2 63.3 77.8

Claims (10)

In a hybrid tire cord for carcass,
A PET single strand made from PET filament yarn of 1500 to 3000 denier;
Aramid yarn produced from aramid filament yarn of 1500 to 3000 denier; And
A PET single yarn and an adhesive coated on the aramid single yarn,
Wherein the PET single yarn and the aramid single yarn are stitched together,
Wherein the length of the aramid single yarn measured after untwisting the upstream side with respect to the hybrid tire cord for a carcass having a predetermined length is 1 to 1.1 times the length of the PET single yarn,
Hybrid tire cord for carcass. The method according to claim 1,
Wherein the PET yarn and the aramid yarn each have a first twist number,
Hybrid tire cord for carcass. 3. The method of claim 2,
Wherein the PET single yarn and the aramid single yarn are stacked together in a second twist number,
Wherein the second twist number is equal to the first twist number,
Hybrid tire cord for carcass. The method according to claim 1,
Wherein the weight ratio of the PET yarn to the aramid yarn is 1: 3 to 3: 1,
Hybrid tire cord for carcass. The method according to claim 1,
Wherein the strength, 3% LASE, 5% LASE, and 7% LASE measured by ASTM D885 are greater than 30 kgf, greater than 8 kgf, greater than 15 kgf, and greater than 25 kgf,
Hybrid tire cord for carcass. The method according to claim 1,
The breaking strength and the elongation at break measured by ASTM D885 are 10.0 to 15.0 g / d and 8 to 15%, respectively,
And the strength retention after disc fatigue test according to JIS-L 1017 is 80% or more,
Hybrid tire cord for carcass. A first step of subjecting the aramid filament yarn of 1500 to 3000 denier to a first direction to form an aramid single yarn;
A second step of lowering the PET filament yarn of 1500 to 3000 denier in the first direction to form a PET single yarn;
A third step of straddling the aramid single yarn and the PET single yarn together in a second direction to form a combined twist yarn;
Immersing the combined yarn in an adhesive solution;
Drying the composite yarn impregnated with the adhesive solution; And
And heat treating the dried composite yarn,
The second direction being opposite to the first direction,
The length of the PET yarn measured after untwisting the upper edge with respect to the combined yarn of a predetermined length is applied to the PET filament in the second step by an amount such that the length of the PET yarn is 1.005 to 1.05 times the length of the aramid single yarn The tension is smaller than the tension applied to the aramid filament in the first step,
A method of manufacturing a hybrid tire cord for carcass. 8. The method of claim 7,
Characterized in that said first, second and third steps are performed by a single twister,
A method of manufacturing a hybrid tire cord for carcass. 8. The method of claim 7,
Wherein the adhesive solution comprises an RFL (Resorcinol Formaldehyde Latex) adhesive or an epoxy adhesive,
The drying step is carried out at 70 to 200 DEG C for 30 to 120 seconds,
The heat treatment step is performed at 200 to 250 DEG C for 30 to 120 seconds,
Wherein the immersion step, the drying step, and the heat treatment step are continuously performed,
A method of manufacturing a hybrid tire cord for carcass. 10. The method of claim 9,
The tensile force applied to the combined yarn in the immersion, drying, and heat treatment steps is 0.4 kg / cord or more,
A method of manufacturing a hybrid tire cord for carcass.