KR100995932B1 - A filament for tire cord, a bundle for tire cord comprising the same, a twisted yarn for tire cord comprising the same, and a tire cord comprising the same - Google Patents

Abstract

The present invention relates to a cross-section filament for a tire cord, a filament bundle for a tire cord including the same, a twist for a tire cord including the same, and a tire cord including the same, and more particularly, a cross section defined according to Formula 1 below. A mold release filament for a tire cord having a release rate greater than 1 and less than 3.0, a filament bundle for a tire cord comprising the same, a twisted product for a tire cord including the same, and a tire cord including the same.

[Calculation 1]

MR = R ² / R ¹

Wherein MR is the cross-sectional release rate, R ¹ is the radius of the largest inscribed circle of the filament cross section, and R ² is the radius of the minimum circumscribed circle of the filament cross section.

Release section, tire cord, cross section release rate, tensile strength, surface area, fatigue resistance

Description

Filament for tire cords, filament bundles comprising the same, twisted articles containing the same, and tire cords comprising the same A TIRE CORD COMPRISING THE SAME}

1 is a cross-sectional view illustrating a cross section of a release cross-section filament.

2 is a diagram showing the definition of the upper and lower edges.

3 shows the definition of the twist angle.

Figure 4 is a graph of the change in tensile strength according to the increase in the number of twist of the tire cord prepared according to Examples 1 to 5 and Comparative Examples 1 to 5.

5 is a graph showing changes in tensile elongation with increasing number of twists of tire cords prepared according to Examples 1 to 5 and Comparative Examples 1 to 5. FIG.

Figure 6 is a cross-sectional photograph of a triangular cross-section release cross-section filament prepared according to Example 6.

7 is a cross-sectional photograph showing an example of measuring the cross-sectional release rate of the release cross-section filament yarn manufactured according to Example 6.

8 is a graph of strong maintenance rate according to the increase in the number of twists of the tire cord prepared according to Examples 6 to 9 and Comparative Examples 6 to 9.

9 is a graph of elongation retention according to the increase in the number of twists of the tire cord prepared according to Examples 6 to 9 and Comparative Examples 6 to 9.

[Industrial use]

The present invention relates to a filament for a tire cord, a filament bundle comprising the same, a twisted product including the same, and a tire cord including the same, and more particularly, less stress due to twisting, and a filament for a tire cord exhibiting excellent mechanical properties. The present invention relates to a filament bundle comprising the same, a twisted article including the same, and a tire cord including the same.

[Private Technology]

The tire cord is used as a skeleton constituting the inside of the tire, and polyester, nylon, rayon, aramid, steel, and the like are used as materials of the tire cord.

The tire has a high temperature due to the friction generated during the driving of the vehicle, and must withstand the load of the vehicle, among other things, the physical properties of such tire is determined by the physical properties of the tire cord forming the skeleton of the tire.

Therefore, the basic performance that the tire cord should have includes high strength and initial modulus, excellent heat resistance, excellent fatigue resistance and form stability, excellent adhesion to tire rubber, and the like.

Most of the tire cords currently known satisfy some of the above-mentioned various physical properties, and some of them do not. Therefore, the tire cords are used according to the inherent physical properties of each material of the cord.

In general, the tire cord is made of a single cord through a process of dipping a cord yarn, dipping the filament fibers, and dipping them into an adhesive and heat treatment.

The single cord is formed into a cord paper through a weaving process, and the filament fibers, which can be regarded as starting materials for the production of cords, have a tendency of deteriorating physical properties through a continuous process for producing cords.

As an example, according to Korean Patent Publication No. 2004-0057550, in the case of a lyocell yarn, when a tire cord is manufactured by twisting and dipping using filament fibers having an initial tensile strength of 7.5 g / d, the tensile strength is 4.99 g / d was 33% below the initial filament value. This tendency depends on the material of the filament fibers, but is a common tendency seen in most tire cords.

An object of the present invention is to provide a release cross-section filament for a tire cord that can minimize the deterioration of physical properties in the manufacturing process of the tire cord, and can exhibit excellent physical properties.

Another object of the present invention is to provide a filament bundle (concentrator) for tire cords including the above-described cross-section filaments.

Still another object of the present invention is to provide a twisted yarn for a tire cord including the release cross-section filament.

Still another object of the present invention is to provide a tire cord including the twisted product.

The present invention provides a release cross-section filament for a tire cord having a cross-sectional release rate greater than 1 and less than or equal to 3.0, which is defined according to the following formula (1).

[Calculation 1]

MR = R ² / R ¹

Wherein MR is the cross sectional release rate, R ¹ is the radius of the largest inscribed circle of the filament fiber cross section, and R ² is the radius of the minimum circumscribed circle of the filament fiber cross section.

The present invention also provides a filament bundle for a tire cord comprising the above-described cross-section filaments and having a total number of filaments of 200 to 2000.

The present invention also provides the twisted yarn for tire cords, which comprises the above-described cross-section filaments, wherein the total number of filaments is 400 to 6000.

The present invention also provides a tire cord comprising the twisted product for the tire cord.

Hereinafter, the present invention will be described in more detail.

Typically, a filament fiber having a circular cross section is used as a tire cord yarn, but a multi-filament yarn having a circular cross section is accompanied by a decrease in physical properties in the twisting process.

In general, yarns such as yarns, cords, and cables have a twist through the twisting process, and when the twist direction is clockwise as shown in FIG. 2, it is referred to as a lower edge (or S lead), and the twist direction is a counterclockwise direction. This is called staging (or Z) ("Introduction to Textile Engineering", Hyungseol Publishing Co., Feb. 25, 1991, page 216).

In particular, according to the twisting per meter (TPM) level that is given in the twisting process, the strength, elongation, fatigue resistance, and fiduciary physical properties of the cord are being changed. As the twist number increases, the strength tends to decrease significantly.

The present inventors through a series of studies to prevent the deterioration of the properties in the twisting process, the yarn is inevitably subjected to a lot of stress in the spiral direction with respect to the fiber axis due to the twisting of the yarn accompanying the twisting process, this stress is deteriorated physical properties In particular, this tendency is more severe as the number of twists increases, and it is found that this phenomenon is more prominent in the case of fibers containing a rigid polymer.

The inventors have studied that the stress caused by twisting during the manufacturing process of the tire cord is mainly solved at the surface of the filament fiber, and when comparing the filament fibers having the same cross-sectional area, the larger the surface area, the more the stress accompanying twist per surface area. It confirmed that it decreases.

The present invention is applied to the results of this study, the tire cord of the present invention is characterized in that it comprises a sectional filament.

Since the cross-section filament of the present invention has a larger surface area than circular cross-section yarns, stress accompanying the twisting of the cord is reduced, thereby preventing the degradation of the physical properties of the cord during the manufacturing process or during operation.

Accordingly, the release cross-section filament for the tire cord of the present invention may be a release cross-section filament yarn having a cross-sectional release rate greater than 1 and less than or equal to 3.0 defined in accordance with Formula 1 below, 1.1 to 3.0, and 1.3 to 2.5. When the cross-sectional release rate of the release cross-section filament is 1, it means a substantially circular cross-section yarn, and may cause a decrease in physical properties due to the twisting process, and at a cross-sectional release rate of 3.0 or less, tire cord without deteriorating absolute physical properties of the release cross-section filament itself Sufficient physical properties can be secured.

[Calculation 1]

MR = R ² / R ¹

In the above formula, MR (Modification Ratio) is the cross-sectional release rate, R ¹ is the radius of the maximum inscribed circle of the filament cross-section, R ² is the radius of the minimum circumscribed circle of the filament cross-section.

In this case, the maximum inscribed circle is defined as a circle having a maximum size such that a circumference does not involve the outside of the cross section of the fiber with an arbitrary point inside the cross section of the fiber, and the minimum inscribed circle is With any point as the center point, the circumference is defined as the smallest size circle that does not invade the interior of the fiber cross section.

Hereinafter, the cross-sectional release rate defined in the present invention means an average value of calculated values obtained from at least 10 filament cross-sectional photographs.

In order to explain R ¹ and R ² defined in Equation 1, cross-sections of the release cross-section filaments are illustrated in FIG. 1.

In the present invention, since the cross-sectional shape of the release cross-section filament is not particularly limited, all of the cross-section filaments such as random, triangular, square, pentagon, etc. polygonal, cross-shaped, Wei-shaped, star-shaped, etc. Although it may correspond to the present invention, it is most preferable that the cross-section filament yarn having a substantially triangular cross section.

In addition, the release cross-section filament of the present invention is characterized by the shape, the material is not particularly limited because the equivalent effect can be obtained for all filament fibers that can be used for the tire cord.

Accordingly, the release cross-section filament may include a cellulose polymer, aramid, polyester polymer, nylon polymer, polyvinyl alcohol polymer, or a mixture of two or more thereof. In this case, the cellulose-based polymer may be rayon or lyocell, and in order to secure mechanical properties such as strength and elongation, the content of alpha-cellulose may be 94 wt% or more, more preferably 96 wt% or more. In addition, the polyester-based polymer may be polyethylene terephthalate, or polyethylenetaphthalate, the nylon-based polymer may be nylon 6, or nylon 66.

The fineness of the release cross-section filament is not particularly limited, but may be 0.8 to 6 d or 1 to 5 d in order to be suitable for the tire cord.

The release cross-section filaments are manufactured in the form of bundles (or clusters) in which multiple release cross-section filaments are focused before being manufactured in the form of tire cords, and the total number of filaments for the tire cord filament bundle of the present invention is 200 To 2000.

In addition, the filament bundle may have a total fineness of 200 to 3000d, and if necessary, the total fineness may be 500 to 2500d.

The bundles form one ply in the manufacture of the cord.

Since the filament bundle includes multiple release cross-section filaments, it may include two or more release cross-section filaments containing different polymers as necessary to compensate for the lack of physical properties of each other, and different cross-sectional release rates as necessary. It is possible to control the effect of improving the strong retention rate and elongation retention rate by including two or more heterogeneous cross-section filaments, and the packing of the filament in the cord by including two or more heterogeneous cross-section filaments having different cross-sectional shapes as necessary. You can also adjust the status.

The filament bundle is manufactured in the form of twisted yarns imparted with twist to be manufactured from a tire cord, and the twisted yarn for the cord of the present invention includes the release cross-section filament, and the total number of filaments may be 400 to 6000.

In addition, the total amount of fineness of the twisted material for the cord may be 400 to 9000d, may be 1000 to 7500d total fineness as needed.

At this time, the twisted yarn for the cord is made from the bundle, so as in the case of the bundle, including two or more different types of cross-section filaments containing different polymers, if necessary, to compensate for the insufficient physical properties of each other, and also necessary It is possible to control the effect of improving the strong retention rate and elongation retention rate, including two or more types of release cross-section filaments having different cross-sectional release rate according to, and also includes two or more release cross-section filaments having different cross-sectional shape as needed It is also possible to adjust the packing state of the filament in the cord.

However, since the corded yarn is manufactured by a first twisting process of streaking or lowering the bundle and a second twisting of the first twisted second twisting yarn 2 to 3 ply and then second twisting to lower or upper streaking. It may include two or more kinds of filaments of different materials, cross-sectional release rate, or cross-sectional shape in the first twisted material, and two to three kinds of materials, cross-sectional release rate, or cross-sectional shape are different in the final twisted material. It may also include the first burst of.

In the twisted product for the tire cord, the number of twists of the first upper or lower lead and the second lower or upper lead may be 200 to 600 TPM, respectively, and the twisted yarn of the present invention may have the twisted range of FIG. Since the twist angle (θ) with respect to the direction (D) perpendicular to the longitudinal direction (L) is 30 to 55 ^o , the number of twists is higher than that of conventional tire cords including circular cross-section yarns and having the same twist angle, resulting in elongation. The effect of oils and fats is particularly excellent.

The twisted yarn for the cord is manufactured in the form of a dip cord by a process of applying an adhesive on the surface, the characteristics of the twisted yarn is applied to the cord of the present invention as it is.

In general, tire cords have higher strength with less twist, while fatigue resistance is lowered, and fatigue resistance is improved with higher twist number of cords, but the strength decreases accordingly.

However, since the tire cord of the present invention includes a hetero sectional filament having a large surface area, the stress associated with the twist of the cord is reduced so that the strength decreases less, or depending on the type of fiber, the upper and lower edges, or the lower and upper edges, respectively, are twisted. In the range of 200 to 600 TPM (Cable & Cord 3 type twister by Allma Co.), it can also be seen that the strength is increased compared to the cord including a circular cross-section yarn. Therefore, the tire cord of the present invention may have a twist number of each of the upper and lower edges or the lower and upper edges of 200 to 600 TPM.

Particularly, in the case of tire cords containing cellulose-based cross-section filaments, a strong retention of 90% or more, elongation retention of 120% or more, and more preferably 130% or more may be obtained at a twisting rate of 350 TPM of upper and lower edges, respectively. At 420 TPM twist strength can be more than 80%, elongation retention can be more than 120%, better 160%, and at 470 TPM twist retention is more than 70% and elongation retention is 120% In the above, it may be better to exhibit an effect of 170% or more.

In the present invention, the strength retention rate is a percentage (%) of the relative ratio of the strength at a specific twist to the strength of the yarn having a twist of 0 TPM, and the elongation maintenance ratio is the specific twist for the elongation of the yarn having a twist of 0 TPM. Percentage of Relative Ratio.

The tire cord of the present invention including the release cross-section filament has a tensile strength of 12 kgf to 70 kgf, and in the case of synthetic fibers such as polyester fibers, it may exhibit a tensile strength of 14 kgf to 70 kgf, and the number of twists 200 It can exhibit a tensile strength of 15 kgf to 60 kgf in the range of to 600 TPM. In addition, in the case of the cellulose-based fiber may exhibit a tensile strength of 12 kgf to 60 kgf, and may exhibit a tensile strength of 14 kgf to 30 kgf within the range of twisting 200 to 600 TPM.

The tire cord of the present invention comprises the steps of: twisting the release cross-section filament bundle to produce a twisted product; And attaching an adhesive solution for a cord to the release cross-section filament yarn, and drying and heat-treating it.

The release cross-section filament can adjust the cross-sectional release rate to the range of the present invention by adjusting the shape of the spinneret, and other detailed spinning conditions can be adjusted within the usual range according to the type of polymer used, which is the present invention Since those skilled in the art can be carried out without difficulty, a detailed description thereof will be omitted.

However, in the case of a cellulose-based cross-section filament, cellulose is dissolved in a mixed solvent of N-methylmorpholine-N-oxide (NMMO) and water to prepare a spinning dope; Spinning a cellulose-based filament from the spinning stock solution using the spinning apparatus equipped with the cross section nozzle; And washing and drying the spun cellulosic filaments so that the cross-sectional release rate of the manufactured filaments is greater than 1 and less than or equal to 3.0.

In this case, as the spinning stock solution, 7 to 18% by weight of cellulose is dissolved in a mixed solvent including N-methylmorpholine-N-oxide (NMMO): water in a weight ratio of 93: 7 to 85:15. Preferably, the spinning solution is swelled in a mixed solvent containing N-methylmorpholine-N-oxide (NMMO): water in a weight ratio of 90:10 to 50:50, and then N-methylmorpholine-N -Oxide (NMMO) can be prepared according to the process of removing water so that the weight ratio of water is 93: 7 to 85:15, the final content of cellulose is 5 to 35% by weight, more preferably 7 to 18% by weight. . The content ratio of the mixed solvent and the content of cellulose are not limited to merely setting a range for producing cellulose-based cross-section filaments under optimum conditions.

In addition, the cross-sectional shape of the release cross-section filament of the present invention is determined according to the shape of the spinning nozzle, the expansion of the fiber spun by the extrusion passes through the nozzle, so that the Y-shaped nozzle to obtain a cross-section filament of the triangular cross section Preference is given to using.

As the adhesive solution attached to the filament fiber twisted yarn of the present invention, a conventional tire cord adhesive may be used, and RFL solution may be preferably used. The drying temperature and heat treatment conditions of the adhesive solution are in accordance with conventional process conditions.

In addition, in the tire cord manufacturing method of the present invention, other process conditions besides using a release cross-section filament are in accordance with a conventional tire cord manufacturing method, and can be added or subtracted as necessary, and therefore, the present invention is not particularly limited.

Hereinafter, preferred embodiments of the present invention will be described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

[Example]

Example 1

A polyethylene terephthalate with an intrinsic viscosity of 0.65 was used to form a polyethylene terephthalate with a Y-shaped mold of 4500 m / min, spinning temperature 289 ° C, cooling wind speed 0.5 m / sec, discharge rate 500g / min, first gourd roll temperature 85 ° C, and second gourd roll. A triangular cross-section polyester (PET) filament having a total fineness of 1000 deniers and a total number of filaments of 250 was spun at a temperature of 125 ° C.

The average cross-section of the release cross-sectional polyester filament fiber was 4 d, the cross-sectional release rate was 1.4, the health was 7.0 g / d, the elongation was 15%.

The cross-sectional release rate of the cross-section filament is obtained by using the SEM (SCANNING ELECTRONIC MICROSCOPY) to obtain the cross-sectional image of the filament, and using the CAD program (Auto CAD 2002) to draw the circle corresponding to the maximum internal and minimum external circumference of the cross-section MR was calculated by measuring the radius of the program. At this time, in order to increase the reliability of the measured values, the average of the measured values for at least 10 filament cross sections was obtained.

The release cross-section filament fiber was prepared using a Cable & Cord 3 type twister (C.C Twister, Allma Co.) at 200 TPM, and then the stranded yarn 2 ply was further lowered at 200 TPM to prepare a cord dough. In this case, however, the direction of the twisting direction may be lowered, and then the method may be performed again.

The cod dough is immersed in a resorcinol-formaldehyde-latex (RFL) adhesive solution comprising resorcinol, formalin, sodium hydroxide, styrene / butadiene / vinylpyridine (15/70/15) rubber, and water, adhesive After passing through 5% by weight, dried for 2 minutes at 150 ℃, heat treatment for 2 minutes at 240 ℃ to prepare a tire cord.

Example 2

Tire cords were prepared in the same manner as in Example 1 except that the twisted edges of the upper and lower edges of the cross-section polyester filament fibers were changed to 370 TPM, respectively.

Example 3

Tire cords were prepared in the same manner as in Example 1 except that the twisted edges of the upper and lower edges of the cross-section polyester filament fibers were changed to 460 TPM, respectively.

Example 4

Tire cords were prepared in the same manner as in Example 1 except that the twisted edges of the upper and lower edges of the cross-section polyester filament fibers were changed to 600 TPM, respectively.

Example 5

Tire cords were prepared in the same manner as in Example 1 except that the twisted edges of the upper and lower edges of the cross-section polyester filament fibers were changed to 750 TPM, respectively.

Comparative Example 1

Tire cords were prepared in the same manner as in Example 1, except that circular cross-section polyester filament fibers having an average fineness of 4 d, a health of 8 g / d, an elongation of 14%, and a filament number of 250 were used.

Comparative Example 2

Tire cords were prepared in the same manner as in Comparative Example 1 except that the twisted upper and lower edges of the circular cross-section polyester filament fibers were changed to 370 TPM, respectively.

Comparative Example 3

A tire cord was prepared in the same manner as in Comparative Example 1 except that the twisted edges of the upper and lower edges of the circular cross-section polyester filament fibers were changed to 460 TPM, respectively.

Comparative Example 4

A tire cord was prepared in the same manner as in Comparative Example 1 except that the twisted edges of the upper and lower edges of the circular cross-section polyester filament fibers were changed to 600 TPM, respectively.

Comparative Example 5

Tire cords were prepared in the same manner as in Comparative Example 1 except that the twisted edges of the upper and lower edges of the circular cross-section polyester filament fibers were changed to 750 TPM, respectively.

The change in tensile strength according to the increase in the number of twists of the tire cords manufactured according to Examples 1 to 5 and Comparative Examples 1 to 5 is shown in FIG. 4. As shown in Figure 4, according to Examples 1 to 5 of the present invention, the tire cord including the release cross-section filament increases the tensile strength according to the increase in the number of twists, while Comparative Examples 1 to 1 including a circular cross-section yarn Tire cord of 5 can be seen that the tensile strength decreases with increasing the number of twists.

In addition, the change in elongation according to the increase in the number of twists of the polyester tire cord prepared according to Examples 1 to 5 and Comparative Examples 1 to 5 is shown in FIG. As shown in Figure 5, according to Examples 1 to 5 of the present invention, the tire cord including the release cross-section filament is a tire cord of Comparative Examples 1 to 5 in which the elongation retention rate includes a circular cross section yarn according to the increase in the number of twists It can be seen that it is higher than elongation retention due to the increase in the number of twists.

From the above results, it can be seen that the tire cord including the release cross-section filament of the present invention is not accompanied by a decrease in strength as the number of twists increases in the twisting step, and the elongation is also higher than that of the circular cross section.

Example 6

The cellulose sheet (buckeye V-81) was put into a grinder equipped with a 100 mesh filter to prepare a cellulose powder having a diameter of 1700 μm or less.

The cellulose powder was swollen in 50 wt% NMMO aqueous solution. At this time, the content of cellulose in the NMMO solution is 6.5% by weight, and antioxidant was added to 0.01% by weight relative to cellulose.

The swelled cellulose slurry was maintained at an internal temperature of 90 ° C. and injected into a kneader maintained at an absolute pressure of 50 mmHg at a rate of 16 kg / hour using a rotary valve pump, while 50% by weight of NMMO aqueous solution was 89% by weight of NMMO aqueous solution. After completely dissolving the cellulose while removing the excess moisture to be discharged through the spinning screw through the discharge screw. At this time, the cellulose concentration of the discharged spinning dope was 11% by weight, it was confirmed that the homogeneous state does not contain undissolved cellulose particles.

The cellulose dope was adjusted to have a final filament total fineness of 1,650 deniers and spun using a Y-type nozzle having 1000 nozzles and a nozzle cross-sectional area of 0.047 mm 2. At this time, an air layer of 30 mm was placed between the nozzle and the coagulation bath.

The discharged and solidified multifilament yarns were completely removed by NMMO by the flushing liquid sprayed through the Nelson roller, and the lyocell multifilament was dried by drying an undried multifilament yarn with a moisture content of 170% on a three-stage drying roll. Yarn was obtained. At this time, the tension between the first and second stages of the drying roll was adjusted to 0.5 g / d, and the tension between the second and third stages was adjusted to 0.8 g / d, and the temperature of each drying roll was sequentially set at 100 ° C, 130 ° C, and 150 ° C. Adjusted to.

The number of filaments of the triangular cross-section lyocell filament yarn prepared by the above method was 1000, the average fineness was 1.5 d, the average cross-sectional release rate was 1.44, the health level was 6.0 g / d, and the elongation was 9%. Figure 6 is a cross-sectional photograph of the manufactured lyocell triangular cross section.

The average cross-sectional release rate was measured in the same manner as in Example 1, and a cross-sectional photograph of a release cross-section filament showing a measurement example of the cross-sectional release rate is shown in FIG. 7.

Comparative Example 6

With 1000 holes and 0.2 mm aperture, use a circular nozzle

The tire cord was prepared in the same manner as in Example 6, except that circular cross-section lyocell filament fibers having an average fineness of 1.5d, a health of 6.2 g / d, an elongation of 8%, and a number of filaments of 1000 were prepared.

Example 7

After the lyocell triangular cross section yarn prepared according to Example 1 was staged at 350 TPM, the yarn 2 ply was further stranded at 350 TPM to prepare a cord dough.

After immersing the cord dough in RFL adhesive solution containing resorcinol, formalin, sodium hydroxide, styrene / butadiene / vinylpyridine (15/70/15) rubber, and water, the adhesive is attached to 5% by weight, The tire cord was prepared by drying at 150 ° C. for 2 minutes and heat-treating at 240 ° C. for 2 minutes.

Example 8

A tire cord was manufactured in the same manner as in Example 7, except that the twisted upper and lower twisted numbers of the lyocell triangular yarn were changed to 420 TPM.

Example 9

Tire cords were manufactured in the same manner as in Example 7, except that the twisted upper and lower twisted numbers of the lyocell triangular yarn were changed to 470 TPM.

Comparative Example 7

A tire cord having a twist number of 350 was manufactured in the same manner as in Example 7, except that the lyocell circular section yarn manufactured according to Comparative Example 1 was used.

Comparative Example 8

A tire cord was manufactured in the same manner as in Comparative Example 7, except that the twisted upper and lower edges of the lyocell circular section yarn were changed to 420 TPM, respectively.

Comparative Example 9

A tire cord was manufactured in the same manner as in Comparative Example 7, except that the twisted edges of the upper and lower edges of the lyocell circular section yarn were changed to 470 TPM.

After the specimens were dried for 2 hours at a temperature of 110 ° C. for the yarns and tire cords prepared according to Examples 6 to 9 and Comparative Examples 6 to 9, and preliminarily dried below the process moisture content, KSK 0901 (Fiber Lab Standard) was used. It was allowed to stand at least 24 hours in a standard state to reach a water equilibrium state.

The prepared specimens were measured for strength and elongation in accordance with the KSK 0412 standard at a sample length of 250 mm and a tensile speed of 300 mm / min using an Instron low speed tensile tester. However, for the experiments under the same conditions, the yarns of Example 6 and Comparative Example 6 were measured after performing the adhesive applying process in the same manner as the remaining examples without twisting.

Strength and strength retention of the yarns and tire cords prepared according to Examples 6 to 9 and Comparative Examples 6 to 9 are shown in Table 1 below, and the change in the strength retention with increasing twist number is shown in FIG. 8.

 TABLE 1

Cross section Twist (TPM) Strong (kgf) Strong retention rate (%) Example 6 triangle 0 (yarn) 19.3 100 Example 7 triangle 350 18.4 95.3 Example 8 triangle 420 16.1 83.4 Example 9 triangle 470 14.9 77.2 Comparative Example 6 circle 0 (yarn) 20.5 100 Comparative Example 7 circle 350 18.1 88.3 Comparative Example 8 circle 420 15.7 76.6 Comparative Example 9 circle 470 14.2 69.3

As shown in Table 1 and FIG. 8, the tire cords of Examples 7 to 9 of the present invention including the release cross-section filament include a circular cross-section yarn, while the decrease in tensile strength is moderate with increasing twist. Tire cords of Comparative Examples 7 to 9 can be seen that the sharp decrease in the tensile strength according to the increase in the number of twists.

In addition, the elongation change according to the increase in the twist number of the lyocell tire cords manufactured according to Examples 6 to 9 and Comparative Examples 6 to 9 is shown in Table 2 below, and the change in the elongation retention rate according to the increase in the twist number is shown in FIG. 9. Indicated.

 TABLE 2

Cross section Twist (TPM) Shinto (%) Elongation Retention Rate (%) Example 6 triangle 0 4.6 100 Example 7 triangle 350 6.5 141 Example 8 triangle 420 6.8 170 Example 9 triangle 470 7.2 180 Comparative Example 6 circle 0 5.7 100 Comparative Example 7 circle 350 6.7 118 Comparative Example 8 circle 420 6.6 116 Comparative Example 9 circle 470 6.7 118

As shown in Table 2 and Figure 9, the tire cords of Examples 7 to 9 of the present invention including the release cross-section filament of Comparative Examples 7 to 9 in which the increase in elongation according to the increase in the number of twists includes a circular cross-section yarn It is much higher than the tire cord.

From the above results, it can be seen that the tire cord including the cellulose-based release cross-section filament of the present invention has a lower strength as the twist count increases, and the elongation also shows a higher level than the circular cross-section.

The reason why the strong deterioration in the tire cord of the present invention is weak is that the release cross-section filaments having a large specific surface area are more favorable to torsion than the circular cross-section filaments. It is an effect shown by further strengthening.

The release cross-section filament for the tire cord of the present invention has a wide surface area and excellent resistance to twisting of the cord, and the tire cord of the present invention includes the above-described cross-section filament, so that the stress due to the kink is reduced, so that the strong maintenance rate and elongation retention rate are reduced. There is an excellent advantage.

Claims (32)

delete delete delete delete delete delete delete delete delete delete delete delete delete It includes a release cross-section filament having a cross-sectional release rate of 1 to 3 or less defined in accordance with Formula 1, The total number of filaments is from 400 to 6000, A twisted product for tire cords, which is manufactured by firstly rolling or lowering a cross-section filament bundle having a total number of filaments of 200 to 2000 and then plying it to 2 to 3 ply again to second or lower rolling. [Calculation 1] MR = R ² / R ¹ Where MR is the cross-sectional release rate, R ¹ is the radius of the largest inscribed circle of the filament cross section, and R ² is the radius of the minimum circumscribed circle of the filament cross section. The method of claim 14, Burst for tire cords with a total fineness of 400d to 9000d. The method of claim 14, Burst for tire cords with a total fineness of 1000 to 7500 d. The method of claim 14, The twisted yarn is a tire cord for twisted yarn containing two or more types of release cross-section filaments containing different polymers. The method of claim 14, The twisted article is a tire cord twisted article comprising two or more types of release cross-section filaments having different cross-sectional release rate. The method of claim 14, The twisted yarn is a tire cord twisted yarn comprising two or more different types of cross-section filaments having a different cross-sectional shape. delete The method of claim 14, The twisted yarn of the primary upper or lower lead and the secondary lower or upper lead has a twist number of 200 to 600 TPM, respectively. The method of claim 21, The twisted product for tire cords whose angle of twist with respect to the direction perpendicular | vertical to the longitudinal direction of the said twisted yarn is 30-55 ^o . A tire cord comprising the twisted article for tire cord according to any one of claims 14 to 19 and 21 to 22. delete delete delete delete delete delete delete delete 24. The method of claim 23, The tire cord is a tire cord having a tensile strength of 12 kgf to 70 kgf.

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