KR102400546B1 - Method and apparatus for manufacturing polyster yarn having high strength - Google Patents

Abstract

In one embodiment of the present invention, forming a plurality of filaments by discharging a molten polyester resin using a nozzle, cooling the plurality of filaments, and converging the cooled plurality of filaments to form a multifilament A method for producing a polyester yarn, comprising the steps of: stretching the multifilament and winding the stretched multifilament, wherein the spinneret has a spinning area per denier of 40 mm ² /d to 80 mm ² /d provides

Description

Manufacturing method of high-strength polyester yarn and manufacturing apparatus thereof

The present invention relates to a method for producing a polyester yarn and an apparatus for producing the same, and more particularly, to a method and apparatus for producing a polyester yarn having excellent strength.

Recently, a polyester yarn made of polyethylene terephthalate (PET) has been used as a material for a tire cord, which is a reinforcing material of a tire.

In general, a polyester yarn melts a polyester chip, discharges the molten polyester through a nozzle to form a plurality of filaments, cools the plurality of filaments, and collects the cooled filaments to form a multifilament, It can be prepared by stretching the multifilaments, and winding the stretched multifilaments.

In order to improve the mechanical properties of the polyester yarn prepared in this way, it is necessary to maximize the draw ratio and the degree of orientation. As a method of improving the mechanical properties of the polyester yarn, there are, for example, the following two methods. One of them is a method applied to the manufacture of high-strength yarns for general industry, and is a method of maximizing the draw ratio after maximizing the orientation of untwisted yarns through low-speed spinning. The other is a method applied to the production of yarn for tire cords requiring excellent shape stability, and is a method of improving the orientation of undrawn yarn through high-speed spinning and then imparting a low draw ratio.

In both of these methods, in order to improve the spinning stability and maximize the orientation of the yarn, for example, a method of delaying the cooling of the filament discharged from the spinneret using a heating hood or an insulating plate can be applied, In addition, a method of irradiating a laser locally on the filament is currently under study to further improve the physical properties. However, even when these methods are applied, a difference in physical properties occurs between the filaments due to a cooling imbalance, causing problems such as some filaments being cut off during stretching. Due to this cooling imbalance, the improvement of the strength of the yarn is limited.

An embodiment of the present invention is to provide a method for producing a polyester yarn and an apparatus for producing a polyester yarn that can improve the strength of the polyester yarn by solving the cooling imbalance of the filaments.

Another embodiment of the present invention is to provide a polyester yarn prepared in this way.

Another embodiment of the present invention is to provide a tire cord including such a polyester yarn.

In addition to the above-mentioned aspects of the present invention, other features and advantages of the present invention will be described below or will be clearly understood by those of ordinary skill in the art from such description.

To this end, an embodiment of the present invention comprises the steps of discharging the molten polyester resin using a nozzle to form a plurality of filaments, cooling the plurality of filaments, and converging the cooled plurality of filaments to multi Forming a filament, stretching the multifilament, and winding the stretched multifilament, wherein the spinneret has a denier of 40 mm ² /d to 80 mm ² /d for uniform cooling of the plurality of filaments A method for producing a polyester yarn having a per-spinning area is provided.

The polyester resin includes polyethylene terephthalate (PET).

The polyester resin has an intrinsic viscosity (I.V.) of 0.8 dl/g to 1.5 dl/g.

The plurality of filaments are spun at a speed of 2000mpm to 4000mpm.

The nozzle includes a discharge surface having a plurality of discharge holes, and the plurality of discharge holes are present in an area other than 40% from the center of the discharge surface based on a radius.

In the cooling step, a cooling wind of 10° C. to 50° C. is used.

The cooling wind is used in a cooling unit through which the plurality of filaments pass, and the cooling unit has a cooling area per denier of 40mm ² /d to 80mm ² /d.

Each of the plurality of filaments has a fineness of 2.0 to 5.0 denier (d).

The polyester yarn has a fineness of 800 to 2,000 denier (d).

The method for producing the polyester yarn may include braiding filaments spun from the spinneret alone or from two or more different spinnerets.

The forming of the multifilaments may further include applying an emulsion to the multifilaments.

In the stretching step, the multifilament is drawn at a draw ratio of 1.5 to 3.0.

Another embodiment of the present invention provides a polyester yarn prepared by the above manufacturing method.

The polyester yarn has a tensile strength of 9 g/d or more.

Another embodiment of the present invention provides a tire cord including the polyester yarn.

The tire cord has excellent twist yarn and heat treatment properties due to uniform filament properties, and thus has excellent strength retention. This tire cord has a strength of at least 8.0 g/d.

Another embodiment of the present invention is a nozzle for discharging the molten polyester resin, a cooling unit for cooling a plurality of filaments formed by discharging the molten polyester resin from the nozzle, the cooled plurality of filaments A focusing unit to form multifilaments by focusing, a stretching unit for stretching the multifilaments, and a winder for winding the stretched multifilaments, wherein the spinneret includes a spinning area per denier of 40mm ² /d to 80mm ² /d It provides an apparatus for producing a polyester yarn having a.

The nozzle includes a discharge surface having the plurality of discharge holes, and the plurality of discharge holes are present in an area other than 40% from the center of the discharge surface based on a radius.

The cooling section has a cooling area per denier of 40 mm ² /d to 80 mm ² /d.

It should be understood that both the above general description and the following detailed description are for the purpose of illustrating or describing the present invention only, and are intended to provide a more detailed description of the claimed invention.

According to an embodiment of the present invention, since a plurality of filaments are formed by a spinneret having a radiation area per denier (d) of 40 to 80 mm ² /d, cooling wind can be easily introduced between the plurality of filaments. Accordingly, the plurality of filaments are uniformly cooled to have uniform physical properties and can be uniformly stretched. The yarn according to an embodiment of the present invention including a plurality of such filaments has high strength characteristics.

In addition, the apparatus for producing a polyester yarn according to an embodiment of the present invention, including a spinneret having a spinning area per denier (d) of 40 to 80 mm ² /d, spins a filament at a high spinning speed to achieve uniform physical properties It is possible to manufacture a plurality of filaments having, and it is possible to impart a high draw ratio to the plurality of filaments due to uniform physical properties, thereby improving the degree of orientation. Accordingly, the strength of the polyester yarn can be maximized.

BRIEF DESCRIPTION OF THE DRAWINGS BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which serve to understand the invention and constitute a part of this specification, illustrate embodiments of the invention, and together with the description, explain the principles of the invention.
1 is a schematic diagram of an apparatus and method for manufacturing a polyester yarn according to an embodiment of the present invention.
2 is a cross-sectional view of a cage according to an embodiment of the present invention.
Fig. 3 is a plan view of the nozzle shown in Fig. 2;
4 is a schematic diagram of a molecular structure before and after stretching of a multifilament according to an embodiment of the present invention.
5 is a schematic diagram of an apparatus and method for manufacturing a polyester yarn in another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments described below are provided for illustrative purposes only to help a clear understanding of the present invention, and do not limit the scope of the present invention.

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 their equivalents.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, with reference to FIGS. 1 to 3, the polyester yarn manufacturing apparatus 100 according to an embodiment of the present invention will be described in more detail.

1 is a schematic diagram of an apparatus 100 and a manufacturing method of a polyester yarn according to an embodiment of the present invention.

Referring to FIG. 1 , an apparatus 100 for manufacturing a polyester yarn according to an embodiment of the present invention includes an extruder 110 , a detention unit 120 , a heating unit 135 , a cooling unit 140 , and a focusing unit. 150 , a stretching unit 160 and a winder 170 are included.

According to an embodiment of the present invention, the nozzle 120 , the heating unit 135 , and the cooling unit 140 may be disposed in one chamber. As such, a system in which the detention 120 and the cooling unit 140 are disposed to be blocked from external air is also referred to as a closed system.

The extruder 110 prepares a molten polyester resin, and transfers the molten polyester resin to the nozzle 120 .

The nozzle 120 produces a plurality of filaments 10 by discharging the molten polyester resin.

Referring to FIG. 1 , the nozzle 120 is mounted on a pack body 131 . In addition, a spinning block 132 surrounds at least a portion of the pack body 131 , and protects the nozzle 120 and the pack body 131 .

Figure 2 is a cross-sectional view of the nozzle 120 according to an embodiment of the present invention, Figure 3 is a plan view of the nozzle shown in FIG.

2 and 3 , the nozzle 120 has an inlet surface 121 and a discharge surface 122 . The inlet surface 121 of the nozzle 120 is referred to as the upper surface, and the discharge surface 122 is also referred to as the lower surface.

The inlet surface 121 of the nozzle 120 is a surface through which the molten polyester resin in the extruder 110 flows. The inlet surface 121 has a plurality of inlet holes 125 . The molten polyester is injected into the nozzle 120 through the inlet hole 125 .

The discharge surface 122 is located opposite to the inflow surface 121 . The discharge surface 122 has a plurality of discharge holes 126 . The plurality of discharge holes 126 are respectively connected to the plurality of inflow holes 125 . As the molten polyester injected into the inlet hole 125 is discharged through the plurality of discharge holes 126 , the polyester is spun. That is, the plurality of filaments 10 are radiated through the discharge hole 126 .

According to an embodiment of the present invention, the slit 120 has a radiation area per denier d of from 40 mm ² /d to 80 mm ² /d. The spinning area of the spinneret per denier means the discharge area of the molten polyester per fineness (denier) of the yarn 30 . In an embodiment of the present invention, the discharge area is the same as the area of the discharge surface 122 .

Specifically, the discharge area per fineness (denier) of the yarn 30 may be calculated from the area of the discharge surface 122 and the fineness (denier) of the yarn 30 . For example, when the discharge surface 122 has a diameter of 160 mm and the yarn 30 has a fineness of 1000 denier (d), the area (discharge area) of the discharge surface 122 is about 40212 mm ² (80 mm x 80 mm) x π), the radiation area per denier is 40.2 mm ² /d.

If the radiation area of the nozzle 120 per denier (d) is less than 40mm ² /d, it is difficult to uniformly cool the plurality of filaments 10 formed by being discharged from the nozzle 120 by the cooling wind. On the other hand, when the radiation area of the nozzle 120 per denier (d) exceeds 80 mm ² /d, the nozzle 120 and the cooling unit 140 are large, and the equipment cost increases.

Meanwhile, the nozzle 120 may have 0.25 to 0.5 discharge holes 126 per unit area (cm ² ). When the number of discharge holes 126 per unit area (cm ² ) of the nozzle 120 is less than 0.25, the nozzle 120 and the cooling unit 140 become large to increase the equipment cost, and when it exceeds 0.5, the filament 10 ) is difficult to be uniformly cooled by the cooling wind.

According to an embodiment of the present invention, the plurality of discharge holes 126 do not exist in an area within 40% of the center C of the discharge surface 122 based on a radius. That is, the discharge hole 126 is present in an area other than 40% from the center C of the discharge surface 122 based on the radius.

2 and 3 , the inflow surface 121 and the discharge surface 122 are circular, and have radii of R0 and R1, respectively. As shown in FIG. 3 , the plurality of discharge holes 126 are disposed in the outer ring region except for the center (C) area of the discharge surface 122 .

Referring to FIG. 3 , a boundary line LB of an area in which the plurality of discharge holes 126 is disposed has a radius of R2. In the discharge surface 122 , the discharge hole 126 is not disposed in a region within the boundary line LB defined by the radius R2 from the center C. Here, the radius R2 of the boundary line LB is 40% or more of the radius R1 of the discharge surface 122 . That is, "0.4 ≤ R2/R1".

When the discharge hole 126 is disposed in an area within 40% of the center (C) of the discharge surface 122 on the basis of the radius, the plurality of filaments 10 discharged from the nozzle 120 are uniformly formed by the cooling wind. difficult to cool Accordingly, non-uniformity of physical properties occurs between the plurality of filaments 10, which leads to deterioration of the physical properties of the yarn.

More specifically, the discharge hole 126 may not be disposed in an area within 70% of the center C of the discharge surface 122 based on the radius.

That is, the radius R2 of the boundary line LB may be located in a range of 40% to 70% of the radius R1 of the discharge surface 122 . That is, it may be "0.4 ≤ R2/R1 ≤ 0.7".

The molten polyester resin is discharged from the nozzle 120 to form a plurality of filaments 10 . These plurality of filaments 10 are in a semi-solid state, and form a bundle.

The heating unit 135 heats the plurality of filaments 10 . The heating unit 135 may be omitted.

The cooling unit 140 cools the plurality of filaments 10 .

The cooling unit 140, for example, may provide a cooling wind to the plurality of filaments (10).

For the production of high-strength polyester yarn, spinning is performed at a high speed of 2000mpm or more, and a high spinning tension is applied at this time. When a high spinning speed and spinning tension are applied, even if the cooling wind for cooling is injected into the filament 10, the cooling wind only moves along the outer filament 10 due to air drag, and the inner filament 10 The cooling air is not transmitted to the furnace. As a result, the outer filament 10 is excessively cooled and the inner filament 10 is not cooled, resulting in a cooling imbalance. In order to solve this, even if the temperature of the cooling wind is lowered and the speed is increased, the cooling difference between the outer and inner filaments 10 is not completely resolved.

The difference in physical properties between the filaments 10 is generated by this cooling imbalance, so that the outer filaments 10 have a high degree of orientation and crystallinity, and the inner filaments 10 have a low degree of orientation and crystallinity. In this case, it is difficult to provide a uniform draw ratio with respect to the entire filament 10 , and when the draw ratio increases, the filament 10 may be broken or cut off during drawing. Therefore, it becomes difficult to manufacture a high-strength yarn by high elongation.

In order to solve the cooling imbalance, it is necessary to allow the cooling wind to sufficiently pass between the filaments (10). To this end, according to an embodiment of the present invention, the slit 120 has a radiation area per denier of 40 to 80 mm ² /d.

When the radiation area of the nozzle per denier is 40 to 80 mm ² /d, the planar area of the nozzle 120 and the cooling unit 140 for smooth cooling is secured, and the cooling imbalance is eliminated. Accordingly, it is possible to manufacture high-strength yarns and manufacture high-strength tire cords.

If the spinning area of the spinneret per denier is less than 40 mm ² /d, the cooling imbalance is not completely resolved, making it difficult to manufacture high-strength yarns. When the spinning area per denier exceeds 80 mm ² /d, high-strength yarn can be manufactured due to the resolution of the cooling imbalance, but the size of the equipment is increased and the equipment cost is increased.

The focusing unit 150 concentrates the cooled plurality of filaments 10 to form the multifilaments 20 . The focusing unit 150 may further include a means for applying an oil agent to the multifilaments 20 , so as to apply an oil agent to the multifilaments 20 .

The stretching unit 160 stretches the multifilaments 20 to manufacture the stretched multifilaments 20 . The stretched multifilament 20 may be referred to as a polyester yarn 30 .

The winder 170 winds the stretched multifilament 20 , that is, the polyester yarn 30 .

Hereinafter, a method of manufacturing the polyester yarn 30 according to an embodiment of the present invention will be described in more detail.

First, the polyester in the form of chips or pellets is put into the extruder 110 and then melted to prepare a molten polyester resin. According to an embodiment of the present invention, polyethylene terephthalate (PET) may be used as the polyester.

Specifically, a polyester chip having an intrinsic viscosity (I.V.) of 0.8 to 1.5 dl/g, for example, a PET chip is put into the extruder 110 and melted.

When the intrinsic viscosity (I.V.) of the polyester is less than 0.8 dl/g, it is difficult to secure a sufficient draw ratio due to the short chain length of the polyester, so it is not easy to manufacture a yarn having high strength.

On the other hand, when the intrinsic viscosity (I.V.) of the polyester exceeds 1.5 dl/g, it is difficult to secure sufficient discharge property or spinnability due to the high viscosity. In order to lower the viscosity, there is a method of applying a high temperature exceeding 305°C. However, the molecular weight of the polyester is reduced by the decomposition reaction at high temperature, so that the polyester yarn 30 may not have sufficient strength, and it may take a long period of solid-state polymerization, which may increase the process cost.

More specifically, the polyester may have an intrinsic viscosity (I.V.) of 1.0 to 1.4 dl/g.

The temperature of the molten polyester resin is maintained at 280 to 305°C. If the temperature of the molten polyester resin is less than 280 ° C., the polyester resin is not sufficiently melted, and the spinning viscosity is increased to decrease the spinnability. On the other hand, when the temperature of the molten polyester resin exceeds 305° C., thermal decomposition may occur due to high temperature, thereby reducing physical properties and making it difficult to express high strength.

More specifically, the temperature of the molten polyester resin while spinning may be maintained at 290 to 300 ℃.

The molten polyester resin is discharged through the nozzle 120 . More specifically, the molten polyester resin is transferred to the nozzle 120 , and is discharged through the discharge hole 126 of the nozzle 120 . A plurality of filaments 10 are spun by discharging the molten polyester resin.

The plurality of filaments may have a spinning speed of 2000mpm to 4000mpm. More specifically, it may have a spinning speed of 2000 to 3000mpm.

When the spinning speed is less than 2000mpm, the shape stability of the tire cord may be deteriorated due to the low spinning tension. When the spinning speed exceeds 4000mpm, the filament 10 may be broken or cut off due to high spinning tension. It is limited, and it is impossible to provide a sufficient draw ratio.

A plurality of filaments 10 in a semi-solidified state are formed as the polyester resin starts to solidify immediately upon being discharged from the detention 120 .

A plurality of high-temperature filaments 10 discharged from the nozzle are solidified by cooling in the cooling unit 140 . The cooling unit 140 provides cooling air to the plurality of filaments 10 . The cooling behavior of the filament 10 has a great influence on the final physical properties of the yarn 30 .

According to an embodiment of the present invention, the cooling of the closed system (Closed System) may be applied so that the plurality of filaments 10 are uniformly cooled.

When slow spinning is applied, cooling quenching by an open system is also applied for cooling. However, when high-speed spinning is applied to manufacture high-strength yarn, a closed-system cooling system is applied to prevent the generation of airflow due to air drag and to block the influence of external cooling imbalance factors. To this end, an annular nozzle 120 and a cooling unit 140 may be applied, which may be arranged in one chamber.

For cooling, a cooling wind of 10 to 50° C. is applied to the plurality of filaments 10 . More specifically, the temperature of the cooling wind may be adjusted in the range of 20 to 40 ℃.

When the temperature of the cooling wind is less than 10° C., a cooling imbalance between the filaments 10 may occur due to rapid cooling, and the energy cost for generating a cooling wind of a low temperature may increase. In addition, the orientation of the filaments 10 or the multifilaments 20 is reduced by quenching, making it difficult to draw at a high draw ratio, which may cause difficulties in manufacturing high-strength yarns. In addition, it may be difficult to apply a direct spin draw (DSD) facility for simultaneous spin drawing.

When the temperature of the cooling wind exceeds 50 ° C., the cooling of the high-temperature filament 10 is not smooth, so hair (毛羽) (lint or pilling) may occur during spinning. Saran (絲亂, thread tangling) may occur.

In order to solve the cooling imbalance by allowing the cooling wind to easily pass between the plurality of filaments 10, according to an embodiment of the present invention, in the nozzle 120 having a radiation area per denier of 40 to 80 mm ² /d The molten polyester is discharged by In addition, the discharge hole 126 is present in an area other than 40% from the center of the discharge surface 122 based on the radius. Accordingly, the polyester is not discharged from the center of the nozzle 120 so that the filament is not spun.

Like the nozzle 120 , the cooling unit 140 may also have a cooling area per denier d of 40 to 80 mm ² /d.

If the cooling area of the cooling unit 140 per denier is less than 40mm ² /d, cooling is not smooth, so it is difficult to manufacture the high-strength polyester yarn 30, and when the cooling area per denier exceeds 80mm ² /d, the size of the facility increases, which increases the cost of equipment.

By such a nozzle 120 and the cooling unit 140, the cooling imbalance is reduced, it is possible to manufacture the high-strength polyester yarn 30 and high-strength tire cord.

The plurality of filaments 10 that are cooled and solidified in the cooling unit 140 are concentrated in the focusing unit 150 to become the multifilaments 20 .

According to an embodiment of the present invention, the focusing unit 150 may apply an emulsion to the multifilament 20 . That is, the multifilament 20 forming step and the emulsion applying step may be performed at the same time. The emulsion application may be performed in a metered oiling (MO) or roller oiling (RO) method.

The multifilaments 20 formed through the focusing process are stretched in the stretching unit 160 . The stretching unit 160 may include first and second godet rollers 161 and 162 . The first godet roller 161 determines the spinning speed and the spinning draft ratio, and the draw ratio is the ratio of the speed of the first godet roller 161 and the speed of the second godet roller 162 . is decided

According to an embodiment of the present invention, the spinning speed may be determined by the speed of the first godet roller 161 . That is, the speed of the first godet roller 161 is the same as the spinning speed. For example, the first godet roller 161 may have a rotation speed of 2000 to 4000mpm. More specifically, the first godet roller 161 may have a rotation speed of 2000 to 3000mpm.

Optionally, a heating means may be disposed between the second godet roller 262 and the winder 170 for heat treatment or heat setting of the stretched multifilament 20 . By adjusting the number of times the multifilaments 20 are wound around the second godet roller 262, the time for the multifilaments 20 to stay in the second godet roller 262 can be adjusted, and through this, the stretched multifilaments 20 ) may be subjected to appropriate heat treatment or heat setting.

According to an embodiment of the present invention, the draw ratio is 1.5 to 3.0.

If the draw ratio is less than 1.5, the alignment of the polyester resin constituting the filament is not sufficient, so that the polyester yarn 30 may not have sufficient strength. When the draw ratio exceeds 3.0, each of the filaments 10 constituting the multi-filament 20 may be broken during the stretching process, and an overload may be applied to the second godet roller 162 and the winder 170 . .

The stretched and heat-treated multifilament 20 is wound by the winder 170 to complete the polyester yarn 30 .

4 is a schematic diagram of the molecular structure before and after stretching of the multifilament 20 according to an embodiment of the present invention.

The multifilament 20 according to an embodiment of the present invention has a regular molecular arrangement both before and after stretching, as illustrated in FIG. 4 . That is, molecular chains and entanglement points of the polyester resin are regularly aligned. Here, the multifilament 20 after stretching may be referred to as the polyester yarn 30 or the drawn yarn.

5 is a schematic diagram of an apparatus 200 and a manufacturing method of a polyester yarn in another embodiment of the present invention.

5, the polyester yarn manufacturing apparatus 200 according to another embodiment of the present invention is an extruder 110, two nozzles 120a and 120b, a heating unit 135, a cooling unit ( 140 ), two focusing parts 150a and 150b , an extending part 160 and a winder 170 .

Hereinafter, in order to avoid duplication, descriptions of the already described components will be omitted.

The extruder 110 manufactures a molten polyester resin, and transfers the molten polyester resin to the first nozzle 120a and the second cage 120b.

The first nozzle (120a) and the second nozzle (120b) discharge the molten polyester resin to form a first plurality of filaments (10a) and a second plurality of filaments (10a). The first plurality of filaments (10a) and the second plurality of filaments (10a) each include a plurality of filaments.

The heating unit 135 heats the first plurality of filaments (10a) and the second plurality of filaments (10a). The heating unit 135 may be omitted.

The cooling unit 140 cools the first plurality of filaments (10a) and the second plurality of filaments (10a).

The first focusing portion 150a forms a first multifilament 20a by focusing the cooled first plurality of filaments 10a, and the second focusing portion 150b is a cooled second plurality of filaments 10a. to form a second multifilament (20b).

The first multifilaments 20a and the second multifilaments 20b are braided to form the mixed multifilaments 21 .

The stretching unit 160 prepares the polyester yarn 31 by stretching the mixed multifilament 21 .

The winder 170 winds the polyester yarn 31 .

Another embodiment of the present invention provides a polyester yarn (30, 31) manufactured by the method described above.

According to another embodiment of the present invention, each of the filaments has a fineness of 2 to 5 denier. More specifically, each of the filaments may have a fineness of 2.5 to 4.0 denier.

If the fineness of the filament is less than 2.0 denier (d), the filament may be cut during stretching, and a cooling imbalance may occur due to interference of the filaments during the spinning process. Accordingly, the strength retention rate in the heat treatment process for manufacturing the tire cord using the polyester yarns 30 and 31 may be reduced.

On the other hand, when the fineness of the filament 10 exceeds 5.0 denier (d), physical properties are deteriorated due to non-uniform cooling inside the filament, and the tie chain is reduced due to the low radial tension, so that the shape stability of the tire cord is reduced. can be lowered

The polyester yarns 30 and 31 according to another embodiment of the present invention include 200 to 400 filaments 10, 10a, 10b, and have a strength of 9 g/d or more.

Tire cords made of polyester yarns 30 and 31, for example, polyester yarns 30 and 31 made of PET, should have high shape stability. To this end, high tension is imparted to the filament made of polyester, and the number of tie chains must be increased. Therefore, according to an embodiment of the present invention, the filament is spun at a high speed of 2000mpm or more.

Another embodiment of the present invention provides a tire cord including such polyester yarn (30, 31). The tire cord according to another embodiment of the present invention may have a strength of 8 g/d or more.

Hereinafter, the present invention will be described in more detail through Preparation Examples and Comparative Examples. However, the following preparation examples and comparative examples are only for helping the understanding of the present invention, and the scope of the present invention is not limited thereto.

<Preparation Example 1-3 and Comparative Example 1-2>

Polyester yarns according to Preparation Examples 1 to 3 were prepared by using the apparatus 200 for producing a polyester yarn shown in FIG. 5 , and Comparative Example using the apparatus 100 for producing a polyester yarn illustrated in FIG. 1 . A polyester yarn according to 1-2 was prepared.

[Production Example 1]

A molten polyester resin was prepared by melting a polyethylene terephthalate (PET) chip having an intrinsic viscosity (I.V.) of 1.25 dl/g. Using two nozzles 120a and 120b having an inlet surface 121 diameter of 180 mm and a discharge surface 122 diameter of 160 mm, the polyester resin melted at a spinning temperature of 295° C. is discharged, respectively, and a plurality of filaments (10a, 10b) was spun. The plurality of filaments (10a, 10b) was cooled with cooling air at 40°C, and a focusing process, a stretching process, and a winding process were sequentially performed. The discharge area per denier, the spinning speed and the draw ratio are as shown in Table 1.

Each of the nozzles (120a, 120b) has 125 discharge holes, and 125 filaments (10a, 10b) are spun from each of the nozzles (120a, 120b), and these are braided in a two-joint manner to obtain 800 denier (d) of A polyester yarn having a fineness was prepared.

[Production Example 2]

A molten polyester resin was prepared by melting a polyethylene terephthalate (PET) chip having an intrinsic viscosity (I.V.) of 1.25 dl/g. Using two nozzles 120a and 120b having an inlet surface 121 diameter of 180 mm and a discharge surface 122 diameter of 160 mm, the polyester resin melted at a spinning temperature of 295° C. is discharged, respectively, and a plurality of filaments (10a, 10b) was spun. The plurality of filaments (10a, 10b) was cooled with cooling air at 40°C, and a focusing process, a stretching process, and a winding process were sequentially performed. The discharge area per denier, the spinning speed and the draw ratio are as shown in Table 1.

Each of the nozzles (120a, 120b) has 125 discharge holes, and 125 filaments (10a, 10b) are spun from each of the nozzles (120a, 120b), and these are braided in a two-joint method to form 1,000 denier (d) of A polyester yarn having a fineness was prepared.

[Production Example 3]

A molten polyester resin was prepared by melting a polyethylene terephthalate (PET) chip having an intrinsic viscosity (I.V.) of 1.25 dl/g. Using two nozzles 120a and 120b having an inlet surface 121 diameter of 180 mm and a discharge surface 122 diameter of 160 mm, the polyester resin melted at a spinning temperature of 295° C. is discharged, respectively, and a plurality of filaments (10a, 10b) was spun. The plurality of filaments (10a, 10b) was cooled with cooling air at 40°C, and a focusing process, a stretching process, and a winding process were sequentially performed. The discharge area per denier, the spinning speed and the draw ratio are as shown in Table 1.

Each of the nozzles (120a, 120b) has 192 discharge holes, and 192 filaments (10a, 10b) are spun from each of the nozzles (120a, 120b), and these are braided in a 2-sum method to obtain 800 denier (d) of A polyester yarn having a fineness was prepared.

[Comparative Example 1]

A molten polyester resin was prepared by melting a polyethylene terephthalate (PET) chip having an intrinsic viscosity (I.V.) of 1.25 dl/g. Using a single nozzle 120 having an inlet surface 121 diameter of 180 mm and a discharge surface 122 diameter of 160 mm, a plurality of filaments 10 are discharged by discharging the molten polyester resin at a spinning temperature of 295 ° C. radiated. The plurality of filaments 10 were cooled with cooling air at 40° C., and a focusing process, a stretching process, and a winding process were sequentially performed. The discharge area per denier, the spinning speed and the draw ratio are as shown in Table 1.

The spinneret 10 has 250 discharge holes, and 250 filaments were spun from the spinneret 120, and a polyester yarn having a fineness of 800 denier (d) was manufactured in a single shot method.

[Comparative Example 2]

A molten polyester resin was prepared by melting a polyethylene terephthalate (PET) chip having an intrinsic viscosity (I.V.) of 1.25 dl/g. Using a single nozzle 120 having an inlet surface 121 diameter of 180 mm and a discharge surface 122 diameter of 160 mm, a plurality of filaments 10 are discharged by discharging the molten polyester resin at a spinning temperature of 295 ° C. radiated. The plurality of filaments 10 were cooled with cooling air at 40° C., and a focusing process, a stretching process, and a winding process were sequentially performed. The discharge area per denier, the spinning speed and the draw ratio are as shown in Table 1.

The spinneret 10 has 250 discharge holes, 250 filaments were spun from the spinneret 120, and a polyester yarn having a fineness of 1000 denier (d) was manufactured in a single shot method.

division yarn fineness
(denier, d) Number of filaments (pcs) detained
discharge area
(mm ² ) per denier
discharge area
(mm ² /d) radial speed
(mpm) draw ratio Preparation Example 1 800 250 40212 50.3 2300 2.52 Preparation 2 1000 250 40212 40.2 2400 2.42 Preparation 3 800 384 40212 50.3 2450 2.37 Comparative Example 1 800 250 20106 25.1 2500 2.32 Comparative Example 2 1000 250 20106 20.1 2550 2.27

<Measurement of tensile strength, intermediate elongation (EASL) and cut elongation of polyester yarn>

Tensile strength, Elongation At Specific Load (EASL) (at 4.5 kgf), and cut elongation of the polyester yarns prepared by Preparation Examples 1-3 and Comparative Examples 1-2, respectively, were measured by the following methods, respectively. was measured, and the results are shown in Table 2 below.

Specifically, according to ASTM D885 standard, using a universal tensile tester of Instron Engineering Corp, Canton, Mass, tensile strength (g/d) of polyester yarn, intermediate elongation under 4.5 kgf load (%) , and cut elongation (%) were measured, respectively.

division Tensile strength (g/d) Medium Elongation(at 4.5kgf)(%) Cutting Elongation (%) Preparation Example 1 9.5 4.6 11.3 Preparation 2 9.0 5.4 11.5 Preparation 3 9.2 4.5 10.9 Comparative Example 1 8.8 4.7 10.5 Comparative Example 2 8.5 5.6 12.1

Referring to Table 2, the polyester yarns of Preparation Examples 1-3 prepared according to embodiments of the present invention have a tensile strength of 9.0 g/d or more. On the other hand, the polyester yarn of Comparative Example 1-2 has a tensile strength of less than 9.0 g/d. As such, the polyester yarns prepared according to the embodiments of the present invention (Preparation Examples 1-3) have excellent tensile strength.

<Production of tire cords> Preparation Examples 4-6 and Comparative Examples 3-4

Tire cords of Preparation Examples 4-6 and Comparative Examples 3-4 were prepared in the same manner and under the same conditions using the polyester yarns prepared in Preparation Examples 1-3 and Comparative Examples 1-2, respectively.

Specifically, by using the polyester yarn prepared in Preparation Example 1-3 and Comparative Example 1-2, upper and lower twisting was performed with a twist number of 470 TPM to prepare a raw cord or greige cord. The prepared raw cord was first dipping in epoxy, second immersed in resorcinol-formaldehyde-latex (RFL), and then dried and heat treated to prepare a tire cord.

The strength, tensile strength, intermediate elongation (at 4.5 kgf), cut elongation, and dry heat shrinkage of the tire cords prepared in Preparation Examples 4-6 and Comparative Examples 3-4, respectively, were measured by the following methods, and the results is shown in Table 3 below.

<Strength, tensile strength, intermediate elongation and cut elongation of tire cord>

According to ASTM D885 method, tensile strength (g/d), intermediate elongation (%) under a load of 4.5 kgf, and elongation at cut (%) of the tire cord were measured using Instron's universal tensile tester, respectively. The strength of the tire cord is calculated as the product of tensile strength (g/d) and fineness.

<Dry heat shrinkage of tire cord>

According to ASTM D4974-04 method, dry heat shrinkage measuring equipment (manufacturer: TESTRITE, model name: MK-V) was used. After measuring the initial length (L1) of the specimen under a load of 0.01 g/d and the length (L2) of the specimen after 2 minutes at 180°C, respectively, the dry heat shrinkage rate of the tire cord ( %) was calculated.

Dry heat shrinkage (%) = [(L1 - L2)/L1] ×100

Condition strong The tensile strength middle-class
(at 4.5kgf) amputee dry heat shrinkage
(at 180 degrees, 2 min, 0.01 g/d) unit kgf g/d % % % Preparation 4 14.1 8.8 4.3 13.6 2.2 Preparation 5 16.6 8.3 5.2 15.6 2.1 Preparation 6 13.6 8.5 4.2 13.5 1.8 Comparative Example 3 12.6 7.9 4.3 13.4 2.4 Comparative Example 4 15.4 7.7 5.3 15.8 2.1

Referring to Table 3, the tire cord (Preparation Example 4-6) manufactured using the polyester yarn of Preparation Example 1-3 has a tensile strength of 8.0 g/d or more and a strength of 13.5 kgf or more. On the other hand, the tire cord (Comparative Example 3-4) manufactured using the polyester yarn of Comparative Example 1-2 had a tensile strength of less than 8.0 g/d.

In particular, when comparing tire cords made of polyester yarn having a fineness of 800 denier (d) (Preparation Example 4, Preparation Example 6 and Comparative Example 3), Preparation Examples 4 and 6 according to embodiments of the present invention The tire cord had a tensile strength of 8.5 g/d or more and a strength of 13.5 kgf or more, whereas the tire cord of Comparative Example 3 had a tensile strength of less than 8.0 g/d and a strength of less than 13.0.

As such, when the polyester yarn manufactured according to the embodiments of the present invention is used, a tire cord having excellent tensile strength and strength can be manufactured.

10: filament 20: multi-filament
110: extruder 120: detention
121: inlet surface 122: discharge surface
125: inlet hole 126: discharge hole
131: pack body 132: radiation block
140: cooling unit 150: focusing unit
160: stretching unit 161: first godet roller
162: second godet roller 170: winder

Claims (17)

discharging the molten polyester resin using a nozzle to form a plurality of filaments;
cooling the plurality of filaments;
forming a multifilament by converging the cooled plurality of filaments;
stretching the multifilament; and
Including; winding the stretched multifilament
the slit has a radiation area per denier of 40 mm ² /d to 80 mm ² /d,
The nozzle has 0.25 to 0.5 discharge holes per unit area (cm ² ),
The nozzle includes a discharge surface having a plurality of discharge holes,
The plurality of discharge holes are present in an area other than 40% from the center of the discharge surface based on a radius,
Method for producing polyester yarn. According to claim 1,
The polyester resin is a method for producing a polyester yarn having an intrinsic viscosity (IV) of 0.8 dl / g to 1.5 dl / g. According to claim 1,
The plurality of filaments is a method for producing a polyester yarn having a spinning speed of 2000mpm to 4000mpm. delete According to claim 1,
A method for producing a polyester yarn in which a cooling wind of 10° C. to 50° C. is applied to the plurality of filaments in the cooling step. 6. The method of claim 5,
The cooling wind is applied by a cooling unit through which the plurality of filaments pass,
The cooling unit has a cooling area per denier of 40 mm ² /d to 80 mm ² /d
Method for producing polyester yarn. According to claim 1,
Each of the plurality of filaments is a method for producing a polyester yarn having a fineness of 2.0 to 5.0 denier (d). According to claim 1,
A method for producing a polyester yarn having a fineness of 800 to 2,000 denier (d). According to claim 1,
A method for producing a polyester yarn comprising the step of braiding at least two different filaments spun from the spinneret. According to claim 1,
Forming the multifilaments, Method for producing a polyester yarn further comprising the step of imparting an emulsion to the multifilaments. According to claim 1,
The stretching step is a method for producing a polyester yarn for stretching the multifilament at a draw ratio of 1.5 to 3.0. A polyester yarn produced by the manufacturing method according to any one of claims 1 to 3, 5 to 11. 13. The method of claim 12,
Polyester yarn having a tensile strength of 9 g/d or more. A tire cord comprising the polyester yarn of claim 12 . 15. The method of claim 14,
A tire cord having a tensile strength of at least 8.0 g/d and a strength of at least 13.5 kgf. a nozzle for discharging the molten polyester resin;
a cooling unit for cooling the plurality of filaments formed by discharging the molten polyester resin from the nozzle;
a focusing unit for converging the cooled plurality of filaments to form a multifilament;
a stretching unit for stretching the multifilament; and
Including; a winder for winding the elongated multifilament
the slit has a radiation area per denier of 40 mm ² /d to 80 mm ² /d,
The nozzle has 0.25 to 0.5 discharge holes per unit area (cm ² ),
The nozzle includes a discharge surface having a plurality of discharge holes,
The plurality of discharge holes are present in an area other than 40% from the center of the discharge surface based on a radius,
A device for manufacturing polyester yarn.
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