KR102544693B1 - Hybrid Tire Cord and Method for Manufacturing The Same - Google Patents

Abstract

Disclosed are high-performance hybrid tire cords capable of realizing high-performance and lightweight tires and a method for manufacturing the same. The hybrid tire cord of the present invention includes a PET lower twisted yarn, an aramid lower twisted yarn, and an adhesive coated on the PET lower twisted yarn and the aramid lower twisted yarn, and in the hybrid tire cord of a predetermined length, after untwisting the upper twisted yarn, The length of the aramid lower-twisted yarn is 1 to 1.1 times the length of the PET lower-twisted yarn.

Description

Hybrid Tire Cord and Method for Manufacturing The Same}

The present invention relates to a hybrid tire cord and a method for manufacturing the same, and more particularly, to a high-performance hybrid tire cord capable of realizing high performance and light weight of a tire and a method for manufacturing the same.

As a reinforcing material for rubber products such as tires, conveyor belts, V-belts, and hoses, fiber cords, in particular, fiber cords treated with adhesives (so-called “dip cords”) are widely used. Materials of the fiber cord include nylon fiber, polyester fiber, rayon fiber, and the like. One of the important ways to improve the performance of the final rubber product is to improve the physical properties of the fiber cord used as a reinforcing material.

Fiber cords used as reinforcing materials for tires are referred to as tire cords. As vehicle performance and road conditions improve, the driving speed of vehicles gradually increases, and research on tire cords capable of maintaining stability and durability of tires even during high-speed driving is being actively conducted.

In addition, as the demand for eco-friendly vehicles increases, weight reduction of vehicles for high fuel efficiency is emerging as a major issue, and for this purpose, research on weight reduction of tires is also being actively conducted.

A tire, which is a composite of fiber/metal/rubber, has a tread located on the outermost surface and in contact with the road surface, a cap ply under the tread, a belt under the cap ply, and a belt under the belt. Includes carcass.

In order to reduce the weight of tires, high-performance tire cords must be prioritized.

Hybrid tire cords made of nylon and aramid have been developed as part of the high performance of tire cords. However, the hybrid tire cords have a problem in that they exhibit low modulus due to the initial manifestation of nylon properties on the S-S curve pattern.

Accordingly, the present invention relates to a hybrid tire cord and a manufacturing method thereof capable of preventing problems caused by the above limitations and disadvantages of the related art.

One aspect of the present invention is to provide a high-performance hybrid tire cord capable of realizing high performance and light weight of a tire.

Another aspect of the present invention is to provide a method for manufacturing a high-performance hybrid tire cord capable of realizing high performance and light weight of a tire at high productivity and low cost while minimizing variation in physical properties.

Other features and advantages of the present invention are described below and will in part be apparent from such description. Alternatively, other features and advantages of the present invention may be understood through practice of the present invention. The objects and other advantages of the present invention will be realized and attained by the structure specified in the detailed description and claims.

According to one aspect of the present invention as described above, as a hybrid tire cord, PET lower twisted yarn; aramid lower twist yarn; and an adhesive coated on the PET lower-twisted yarn and the aramid lower-twisted yarn, wherein the PET lower-twisted yarn and the aramid lower-twisted yarn are twisted together, and in the hybrid tire cord of a predetermined length, after untwisting the upper-twisted yarn, the aramid lower-twisted yarn A hybrid tire cord having a length of 1 to 1.1 times the length of the PET lower twisted yarn is provided.

The PET lower-twisted yarn has a first twisting direction, the aramid lower-twisted yarn has a second twisting direction, the PET lower-twisted yarn and the aramid lower-twisted yarn are staging together in a third twisting direction, and the second twisting direction is the first twisted direction. direction, and the third twist direction is opposite to the first twist direction.

The weight ratio of the PET lower-twist yarn and the aramid lower-twist yarn may be 20:80 to 80:20.

The hybrid tire cord may have a breaking strength and an elongation at break of 8.0 to 15.0 g/d and 5 to 15%, respectively, measured by ASTM D885, and according to the JIS-L 1017 method of the Japanese Standard Association (JSA). The strength retention rate after the disk fatigue test performed according to the method may be 80% or more.

In the hybrid tire cord, 3% LASE (Load at Specific Elongation), 5% LASE, and 7% LASE measured by ASTM D885 are 1.0 g/d to 5.0 g/d and 3.0 g/d to 8.0 g/d, respectively. , and 6.0 g/d to 13.0 g/d.

The hybrid tire cord may have a dry heat shrinkage of 0.3 to 2.5% measured at an initial load of 0.01 g/d for 2 minutes at 180° C.

According to another aspect of the present invention, a first step of lowering the aramid filament in a first direction to form an aramid lower twisted yarn; a second step of untwisting the PET filament in a second direction to form a PET under-twisted yarn, wherein the second step is performed simultaneously with the first step; a third step of performing together the aramid lower-twisted yarn and the PET lower-twisted yarn in a third direction to form a raw cord, wherein the third step is performed successively with the first and second steps; immersing the raw cord in an adhesive solution; drying the raw cord impregnated with the adhesive solution by the immersion process; and completing a dip cord by heat-treating the dried raw cord, wherein the first, second and third steps are performed by one twisting machine, and the second direction is the same as the first direction. And, the third direction is a direction opposite to the first direction, and the tension applied to the PET filament in the second step is less than the tension applied to the aramid filament in the first step. is provided.

In the raw cord of a predetermined length, the tension applied to the PET filament in the second step is such that the length of the PET lower twisted yarn after untwisting the upper twisted yarn can be 1.005 to 1.050 times the length of the aramid lower twisted yarn. It may be less than the tension applied to the aramid filament in step 1.

The adhesive solution may include a Resorcinol Formaldehyde Latex (RFL) adhesive or an epoxy-based adhesive, 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 200 to 250 ° C for 30 seconds. to 120 seconds, the immersion step, the drying step, and the heat treatment step may be continuously performed, and the tension applied to the furnace cord in the immersion step, the drying step, and the heat treatment step is 0.4 kg/cord per cord can be more than cord.

In the dip cord having a predetermined length, the length of the aramid lower twisted yarn after untwisting the upper twist may be 1 to 1.1 times the length of the PET lower twisted yarn.

It is to be understood that both the above general description and the following detailed description are merely intended to illustrate or describe the present invention, and to provide a more detailed description of the claimed subject matter.

According to the present invention, since the upper and lower windings are performed by a single twisting machine, productivity of hybrid tire cords can be improved and manufacturing costs can be reduced.

In addition, thanks to the high strength of aramid, the hybrid tire cord of the present invention can minimize tire deformation during high-speed driving.

In addition, since the hybrid tire cord of the present invention has a stable structure with substantially the same number of twists and substantially the same length as the aramid lower-twisted yarn and the PET lower-twisted yarn, variation in physical properties and defect rates that may occur during the manufacturing process can be minimized.

In addition, according to the present invention, since the length of the aramid lower-twisted yarn after untwisting the tire cord is 1 to 1.1 times the length of the PET lower-twisted yarn, the stress applied to the tire cord when tension/compression of the tire is repeated is only the aramid lower-twisted yarn In addition, it can be dispersed in PET lower twisted yarn. As a result, the hybrid tire cord of the present invention having excellent fatigue resistance can maintain the stability of the tire even during high-speed driving for a long time.

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

It will be apparent to those skilled in the art that various changes and modifications of the present invention are possible without departing from the spirit and scope of the present invention. Accordingly, the present invention includes all modifications and variations falling within the scope of the invention described in the claims and equivalents thereof.

As used herein, the term "primarily twisted yarn" refers to a single yarn made by twisting one filament in either direction.

As used herein, the term "plied yarn" refers to a yarn made by twisting two or more lower-twisted yarns together in one direction, and is also referred to as "raw cord".

As used herein, the term "tire cord" means a plied yarn containing an adhesive so that it can be directly applied to a rubber product, and is also referred to as "dip cord".

As used herein, "twist number" means the number of twists per 1 m, and its unit is TPM (Twist Per Meter).

In order to develop a high-performance tire cord, it is necessary to consider both the physical properties of the material itself and structural aspects such as number of twists and shapes.

The tire cord according to the present invention is a hybrid type of PET and aramid, and includes a PET lower twisted yarn in a first twist direction and an aramid lower twisted yarn in a second twist direction, and the PET lower twisted yarn and the aramid lower twisted yarn are together in a third twist direction. It is staged.

By simultaneously untwisting the PET filament and the aramid filament by one twisting machine (for example, a cable cord twisting machine), the PET lower-twisted yarn and the aramid lower-twisted yarn are formed, and almost simultaneously (ie, continuously) with the PET untwisted yarn and the aramid lower-twisted yarn. Saga is performed together to form a raw cord. The second twisting direction of the aramid lower-twisted yarn is the same as the first twisting direction of the PET lower-twisted yarn, and the third twisting direction (ie, the upper twisting direction) is opposite to the first twisting direction.

Since the lower twisting and upper twisting are performed by one twisting machine, it is possible to improve the productivity of the hybrid tire cord and reduce manufacturing cost compared to a batch method in which each lower and upper twisting is performed using different twisting machines.

On the other hand, since aramid has a linear molecular chain, it has high crystallinity and almost no shrinkage behavior by heat. On the other hand, the PET filament manufactured through the drawing process to express the high strength and high modulus required for tire cords shrinks during the heat treatment process performed in the process of manufacturing the dip cord, and as a result, the aramid lower twisted yarn and PET filament in the final tire cord A difference in the length of the lower twisted yarn occurs, resulting in non-uniformity in physical properties. If the shape of the deep cord is non-uniform due to shrinkage of the PET lower-twisted yarn, the aramid lower-twisted yarn and the PET lower-twisted yarn are separated, resulting in a decrease in strength and a decrease in fatigue performance.

Therefore, according to the present invention, in order to manufacture a hybrid tire cord having high strength and fatigue performance, the tension applied to the aramid filament and the PET filament is adjusted during the twisting process, so that the PET lower-twisted yarn is longer than the aramid lower-twisted yarn. In addition, a relatively high level of tension may be applied to the raw cord in order to minimize shrinkage of the PET lower twisted yarn during the heat treatment process.

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

According to the present invention, in a raw cord of a predetermined length, the length of the PET lower twisted yarn after untwisting the upper twist is 1.005 to 1.050 times the length of the aramid lower twisted yarn. That is, the raw cord of the present invention has a structure in which the lower twisted yarn of PET covers the lower twisted yarn of aramid (ie, “covering structure”) is slightly added to the merged structure.

In the raw cord of the present invention, since the length of the PET lower-twisted yarn is longer than the length of the aramid lower-twisted yarn, the final tire cord ( That is, it is possible to prevent the length of the aramid lower-twisted yarn from being excessively longer than that of the PET lower-twisted yarn in the deep cord). According to a preferred embodiment of the present invention, the length of the aramid lower twisted yarn after untwisting the upper twist in the final tire cord of a predetermined length is 1 to 1.1 times the length of the PET lower twisted yarn.

If the aramid under-twisted yarn in the tire cord is shorter than the PET under-twisted yarn (i.e., when the length of the PET under-twisted yarn in the low cord exceeds 1.050 times the length of the aramid under-twisted yarn), the tire cord is subjected to repeated tension/compression. Since stress is intensively applied to the lower twisted yarn of aramid, the fatigue resistance of the tire cord is inevitably low, and the stability of the tire cannot be guaranteed during high-speed driving for a long time due to such low fatigue resistance.

On the other hand, when the length of the PET lower-twisted yarn in the raw cord is less than 1.005 times the length of the aramid lower-twisted yarn, a tire cord having a covering structure in which the length of the aramid lower-twisted yarn exceeds 1.1 times the length of the PET lower-twisted yarn is finally obtained. In the tire cord with such a covering structure, since the aramid lower twisted yarn covering the PET lower twisted yarn is pushed by friction with a guide or roller to form a loop, which causes shape irregularities, deviation in physical properties and defective rate during tire cord manufacturing will increase. In addition, in the tire manufacturing process, the tire defect rate increases due to the variation in physical properties.

According to the present invention, the same number of twists is applied within the range of 200 to 500 TPM when lowering and upper-twisting for the manufacture of the raw cord is performed. However, when the subsequent dipping, drying, and heat treatment processes for applying the adhesive are sequentially performed, unintended untwist may occur, resulting in a difference of less than 15% from the initially set number of twists in the lower and upper ends. there is. In general, when the number of twists in the fiber is high, the strength is reduced but the fatigue performance is increased. On the other hand, as the number of twists in the fiber decreases, the strength increases but the fatigue performance decreases.

According to the present invention, since the aramid lower-twisted yarn and the PET lower-twisted yarn have substantially the same number of twists, length, and structure, the lower-twisted yarns exhibit similar behavior in terms of strength and fatigue performance.

The aramid filament and the PET filament used for manufacturing the hybrid tire cord of the present invention are not particularly limited, but have the same or similar fineness within the range of 400 to 3000 denier.

Aramid contains a phenyl ring along with an amide group in the main chain, and is classified into para type (p-) and meta type (m-) according to the connection state of the phenyl ring. According to a preferred embodiment of the present invention, the aramid is poly(p-phenyleneterephthalamide).

According to one embodiment of the present invention, the aramid filament has a fineness of 400 to 3000 denier, a tensile strength of 20 g / d or more, and a breaking elongation of 3% or more. If the tensile strength of the aramid filament is less than 20 g/d, the risk of tire deformation increases during high-speed driving because the low strength of the PET filament cannot be sufficiently compensated for.

Since the aramid filament has a modulus 5 to 10 times that of the PET filament, even if the weight ratio of the aramid lower-twist yarn and the PET lower-twist yarn is only about 15:85 in the hybrid tire cord, the modulus is 2 to 3 times that of the tire cord made of a single PET material. Therefore, the weight ratio of the aramid lower-twist yarn and the PET lower-twist yarn may be determined in consideration of 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 lower-twist yarn and the PET lower-twist yarn is 20:80 to 80:20.

When the weight of the PET lower-twisted yarn exceeds 4 times the weight of the aramid lower-twisted yarn, the finally obtained hybrid tire cord follows the physical properties of PET, resulting in insufficient strength and modulus, and a large amount of tire cord is used to make up for the insufficient strength and modulus. must be used, and as a result it becomes impossible to reduce the weight of the tire.

On the other hand, if the weight of the aramid lower-twisted yarn exceeds 4 times the weight of the PET lower-twisted yarn, the fatigue resistance of the hybrid tire cord deteriorates, making it difficult to secure the durability of the tire, and the cost increases due to the use of a large amount of expensive aramid.

The hybrid tire cord according to an embodiment of the present invention further includes an adhesive coated on the PET lower-twisted yarn and the aramid lower-twisted yarn to improve adhesion with the tire, and the breaking strength and elongation at break measured by ASTM D885 are 8.0 to 15.0 g / d and 5 to 15%, respectively, and the strength retention after the disk fatigue test conducted according to the JIS-L 1017 method of the Japanese Standard Association (JSA) may be 80% or more. In addition, in the hybrid tire cord, 3% LASE, 5% LASE, and 7% LASE measured by ASTM D885 are 1.0 g / d to 5.0 g / d, 3.0 g / d to 8.0 g / d, and 6.0 g / d, respectively. g/d to 13.0 g/d. The hybrid tire cord may have a dry heat shrinkage of 0.3 to 2.5% measured at an initial load of 0.01 g/d for 2 minutes at 180° C.

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

Aramid filament of 400 to 3000 denier and PET filament of 400 to 3000 denier are fed into a cable cord twister that performs both lower and upper winding. In the twisting machine, the first step of untwisting the aramid filament in a first direction to form an aramid under-twisted yarn and the second step of unwinding the PET filament in a second direction to form a PET under-twisted yarn are simultaneously performed, A third step of performing the aramid lower twisted yarn and the PET lower twisted yarn together in a third direction in order to form is performed successively with the first and second steps. As described above, the second direction is the same direction as the first direction, the third direction is the opposite direction to the first direction, and the same direction is performed within the range of 200 to 500 TPM when performing the lower and upper stages. Twisting is applied.

According to the present invention, since the ply-twisted yarn is produced in a continuous method in which lower-twisting and upper-twisting are performed in one twisting machine, a batch type of untwisting PET filaments and aramid filaments with different twisting machines and then performing them together with another twisting machine. Compared to the method, productivity of hybrid tire cords can be improved.

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, even though lower twisting and upper twisting are performed by one twisting machine, the length of the aramid lower twisted yarn after untwisting the upper twist in the raw cord of a predetermined length may be slightly shorter than the length of the PET lower twisted yarn.

According to one embodiment of the present invention, after untwisting the upper twist in the raw cord of a predetermined length (ie, after untwisting the ply-twisted yarn), the length of the PET lower twisted yarn is 1.005 to 1.050 times the length of the aramid lower twisted yarn. To the extent possible, 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.

The amount of tension applied to the PET filament and the aramid filament can be adjusted by appropriately setting the rpm of the rolls of the twisting machine.

Subsequently, the step of immersing the raw cord in the adhesive solution, the step of drying the raw cord impregnated with the adhesive solution, and the step of heat-treating the dried raw cord are performed successively, thereby producing the hybrid tire cord of the present invention (that is, , deep code) is completed.

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

Although the temperature and time of the drying process may vary depending on the composition of the adhesive solution, the drying process is typically performed at 70 to 200° C. for 30 to 120 seconds.

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

Through the above processes, the adhesive component of the adhesive solution is coated on the surface of the raw cord, thereby increasing the adhesion between the hybrid tire cord of the present invention and the rubber composition for manufacturing a tire.

On the other hand, although the twisting machine is set to perform lower twisting and upper twisting with the same number of twists, untwisting may occur in the process of drying and heat-treating the ply-twisted yarn (i.e., raw cord) produced by the twisting machine after being immersed in the adhesive solution. there is. In order to minimize this untwisting phenomenon (for example, to ensure that the difference between the initially set number of twists and the actual number of twists in the final tire cord is less than 15% of the first set number of twists) and to prevent excessive shrinkage of the PET plied yarn. In order to do this, it is preferable that the tension applied to the raw cord in the immersion, drying, and heat treatment steps performed continuously is 0.4 kg/cord or more per cord.

According to the present invention, it is possible to significantly reduce twist defects in the twisting process, and since the ply-twisted yarn has a stable structure, it is possible to minimize physical property deviation due to shape non-uniformity. Specifically, in the case of the hybrid tire cords of the present invention manufactured under the same conditions, the difference between the maximum and minimum values of each property can be significantly reduced. For example, the difference between the maximum and minimum values of cutting strength is 3 g/d or less, and the difference between the maximum and minimum elongation at break is 5% or less.

Hereinafter, the effect of the present invention will be described through specific examples and comparative examples of the present invention. However, the following examples are only for helping understanding of the present invention, but do not limit the scope of the present invention.

Example 1

1000 denier PET filament and 1000 denier aramid filament are put into a cable cord twisting machine, and the lower winding in the Z-direction and the upper winding in the S-direction are simultaneously performed, respectively, to form a 2-ply yarn (ie, low cord) ) was prepared. At this time, the cable cord twisting machine was set with the number of twists of 460 TPM for the lower winding and upper winding, and by adjusting the tension applied to the PET filament and the aramid filament, respectively, the length of the PET lower twisted yarn relative to the aramid lower twisted yarn in the low cord The ratio (ie, PET lower twisted yarn length/aramid lower twisted yarn length) was set to 1.005. In order to obtain the length ratio of the aramid lower-twisted yarn and the PET lower-twisted yarn, the length of the aramid lower-twisted yarn and the PET lower-twisted yarn were separated from each other by untwisting the upper twist by applying a load of 0.05 g/d to a 1m-long raw cord sample. The lengths were each measured under a load of 0.05 g/d.

The raw code was then mixed with 2.0% by weight of resorcinol, 3.2% by weight of formalin (37%), 1.1% by weight of sodium hydroxide (10%), and 43.9% by weight of styrene/butadiene/vinylpyridine (15/70/ 15) Dipped in a resorcinol-formaldehyde-latex (RFL) adhesive solution containing rubber (41%), and water. The furnace cord containing the RFL solution by immersion was dried at 150° C. for 100 seconds and heat-treated at 240° C. for 100 seconds to complete the dip cord. The tension applied to the 2-ply-twisted yarn during the dipping, drying, and heat treatment processes was 0.5 kg/cord.

Example 2

A dip cord was manufactured in the same manner as in Example 1, except that the ratio of the length of the lower-twisted yarn to the lower-twisted yarn of PET in the raw cord was 1.010.

Example 3

A dip cord was manufactured in the same manner as in Example 1, except that in the raw cord, the ratio of the length of the lower twisted PET yarn to the lower twisted aramid yarn was 1.020.

Example 4

A dip cord was manufactured in the same manner as in Example 1, except that the ratio of the length of the PET lower twisted yarn to the aramid lower twisted yarn in the raw cord was 1.030.

Example 5

A dip cord was manufactured in the same manner as in Example 1, except that in the low cord, the ratio of the length of the lower twisted PET yarn to the lower twisted aramid yarn was 1.050.

Comparative Example 1

The cable cord twisting machine was set with the number of twists of 360 TPM for the lower twisting and upper twisting, and the dip was performed in the same manner as in Example 1 except that the ratio of the length of the PET lower twisted yarn to the aramid lower twisted yarn in the raw cord was 0.980. code was created.

Comparative Example 2

The cable cord twisting machine was set with the number of twists of 400 TPM for the lower twisting and upper twisting, and the dip was performed in the same manner as in Example 1 except that the ratio of the length of the PET lower twisted yarn to the aramid lower twisted yarn in the raw cord was 0.980. code was created.

Comparative Example 3

The cable cord twisting machine was set with the number of twists of 430 TPM for the lower twisting and upper twisting, and the dip was performed in the same manner as in Example 1 except that the ratio of the length of the PET lower twisted yarn to the aramid lower twisted yarn in the raw cord was 0.980. code was created.

Comparative Example 4

A dip cord was manufactured in the same manner as in Example 1, except that in the raw cord, the ratio of the length of the lower twisted PET yarn to the lower twisted aramid yarn was 0.980.

Strength, medium weight (at 4.5 kg), breakage, dry heat shrinkage, and disk fatigue characteristics of the dip codes obtained by Examples 1-5 and Comparative Examples 1-4 were measured by the following methods, respectively, and the results are shown in the table below. 1.

* strong (kgf), moderate (at 4.5 kg) (%), and sore (%)

According to the ASTM D-885 test method, by applying a tensile speed of 300 m/min to 10 samples of 250 mm using an Instron tester (Instron Engineering Corp., Canton, Mass), 4.5 kg) and cut-off were measured, respectively. Subsequently, the strength, medium strength (at 4.5 kg) and cutoff of the deep code were obtained by calculating the average values of the strong, medium strong (at 4.5 kg) and cutoff of the 10 samples, respectively.

* Dry heat shrinkage (%)

After being left for more than 24 hours under atmospheric conditions of a temperature of 25 ° C and a relative humidity of 65%, it was measured under an initial load of 0.01 g / d (20 g) at 180 ° C for 2 minutes using a Testrite device.

* Disc fatigue characteristics

After preparing a sample by vulcanizing the dip cord whose strength (strength before fatigue) is measured into rubber, a Disk Fatigue Tester is used according to the JIS-L 1017 method of the Japanese Standard Association (JSA) While rotating at 80 ° C. at a speed of 2500 rpm, fatigue was applied to the sample by repeating tension and contraction within a range of ± 8% for 16 hours. Subsequently, after removing the rubber from the sample, the fatigue strength of the dip cord was measured. The strength retention rate defined by Equation 1 below was calculated based on the strength before fatigue and the strength after fatigue.

<Equation 1>: Strength retention rate (%) = [strength after fatigue (kgf) / strength before fatigue (kgf)] × 100

Here, the strength (kgf) before and after fatigue is 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-885 test method. It was obtained by measuring the breaking strength (Strength at Break) of the deep cord while applying.

PET length/aramid length
(Raw Cord) strong
(kgf) Medium weight (at 4.5kg)
(%) desperate
(%) Dry heat shrinkage
(%) strong retention rate
(%) Example 1 1.005 24.1 2 9.3 1.02 90.3 Example 2 1.010 25.6 1.9 9.3 1.02 92.5 Example 3 1.020 24.6 2 8.9 0.96 96.4 Example 4 1.030 24.7 1.9 8.9 0.96 98.7 Example 5 1.050 24.2 1.7 7.2 0.89 95.1 Comparative Example 1 0.980 26.3 1.8 7.7 0.85 41.6 Comparative Example 2 0.980 23.6 2.2 8.6 0.8 59.9 Comparative Example 3 0.980 23.5 2.3 9.1 0.88 53.9 Comparative Example 4 0.980 22.6 2.5 13.1 0.87 68.1

Claims (10)

In the hybrid tire code,
PET lower twisted yarn;
aramid lower twist yarn; and
Including an adhesive coated on the PET lower twisted yarn and the aramid lower twisted yarn,
The PET lower twisted yarn and the aramid lower twisted yarn are performed together,
In the hybrid tire cord having a predetermined length, the length of the aramid lower twisted yarn after untwisting the upper twist is 1 to 1.1 times the length of the PET lower twisted yarn,
3% LASE, 5% LASE, and 7% LASE measured by ASTM D885 are 1.0 g/d to 5.0 g/d, 3.0 g/d to 8.0 g/d, and 6.0 g/d to 13.0 g/d, respectively. ego,
In the raw cord formed by staging together the PET lower twisted yarn and the aramid lower twisted yarn of a predetermined length, the length of the PET lower twisted yarn after untwisting the upper twisted yarn is 1.005 to 1.050 times the length of the aramid lower twisted yarn,
The difference between the maximum and minimum values of the breaking strength measured by ASTM D885 is 3 g / d or less, and the difference between the maximum and minimum values of the elongation at break is 5% or less,
Hybrid tire code. According to claim 1,
The PET lower twisted yarn has a first twisting direction,
The aramid lower twisted yarn has a second twist direction,
The PET lower twisted yarn and the aramid lower twisted yarn are staged together in a third twist direction,
The second twist direction is the same direction as the first twist direction,
The third twist direction is opposite to the first twist direction,
Hybrid tire code. According to claim 1,
The weight ratio of the PET lower-twisted yarn and the aramid lower-twisted yarn is 20:80 to 80:20,
Hybrid tire code. According to claim 1,
Breaking strength and elongation at break measured by ASTM D885 are 8.0 to 15.0 g / d and 5 to 15%, respectively,
The strength retention rate after the disk fatigue test conducted according to the JIS-L 1017 method of the Japanese Standard Association (JSA) is 80% or more,
Hybrid tire code. delete According to claim 1,
A dry heat shrinkage of 0.3 to 2.5% measured at an initial load of 0.01 g / d for 2 minutes at 180 ° C.
Hybrid tire code. A first step of untwisting the aramid filament in a first direction to form an aramid under-twisted yarn;
a second step of untwisting the PET filament in a second direction to form a PET under-twisted yarn, wherein the second step is performed simultaneously with the first step;
a third step of performing together the aramid lower-twisted yarn and the PET lower-twisted yarn in a third direction to form a raw cord, wherein the third step is performed successively with the first and second steps;
immersing the raw cord in an adhesive solution;
drying the raw cord impregnated with the adhesive solution by the dipping step; and
Completing a deep code by heat-treating the dried raw code,
The first, second and third steps are performed by one twisting machine,
The second direction is the same direction as the first direction,
The third direction is an opposite direction to the first direction,
In the raw cord of a predetermined length, the tension applied to the PET filament in the second step in the first step is such that the length of the PET lower twisted yarn after untwisting the upper twist is 1.005 to 1.050 times the length of the aramid lower twisted yarn. Less than the tension applied to the aramid filament,
A method of manufacturing the hybrid tire cord of claim 1. delete According to claim 7,
The adhesive solution includes a Resorcinol Formaldehyde Latex (RFL) adhesive or an epoxy-based adhesive,
The drying step is performed at 70 to 200 ° C. for 30 to 120 seconds,
The heat treatment step is performed at 200 to 250 ° C. for 30 to 120 seconds,
The immersion step, the drying step, and the heat treatment step are performed continuously,
The tension applied to the raw cord in the immersion step, the drying step, and the heat treatment step is 0.4 kg / cord or more per cord,
Manufacturing method of hybrid tire cord. According to claim 9,
In the dip cord of a predetermined length, after untwisting the upper twist, the length of the aramid lower twisted yarn is 1 to 1.1 times the length of the PET lower twisted yarn,
Manufacturing method of hybrid tire cord.