KR20240045445A - Manufacturing method of eco-friendly recycled polyester(FD) elastic composite yarn and yarn and fabric manufactured therefrom - Google Patents

Abstract

Eco-friendly recycled polyester (FD) partially oriented yarn (POY) is manufactured by performing crystallization drying and dehumidifying drying on recycled polyester flakes under constant temperature conditions and spinning them, and this polyester (FD) partially oriented yarn (POY) and recycled yarn are produced. By plying polyester-based latent crimped yarn together to form air entanglements, recycled polyester (FD) elastic composite yarn with excellent tactile feel and excellent elasticity is manufactured. The composite yarn produced in this way is an eco-friendly material that recycles discarded resources, and is an elastic composite yarn with excellent volume, lightness, and absorbency, and can be competitive as a clothing fabric.

Description

Manufacturing method of eco-friendly recycled polyester (FD) elastic composite yarn and yarn and fabric manufactured therefrom}

The purpose is to develop recycled polyester materials by recycling waste plastics and to develop sustainable materials with functionality and differentiated natural sensibility that utilize the advantages of elasticity and eco-friendly materials.

It is said that millions to tens of millions of tons of polyester plastic enter the sea every year, and there are more than 1 million pieces of plastic per 1㎢ of sea. Polyester plastic pieces are found in the bodies of a wide variety of sea animals, and are used in marine life and ecosystems. In addition to the impact on human health, there are concerns about adverse socioeconomic impacts due to pollution.

Korea uses a combination of incineration and landfill methods to dispose of waste, but it is impossible to build any more incineration facilities due to opposition from residents, and the metropolitan area landfill, the world's largest, is also destined to be discontinued in 2025. In addition, China, which imported and disposed of about half of the world's recyclable waste, declared to the World Trade Organization (WTO), "We will take measures to restrict the import of plastic waste and electronic waste to protect the environment and improve health and hygiene," thereby affecting not only Korea. In fact, a ‘garbage crisis’ is occurring all over the world.

Recycled plastics produced from waste plastics can be applied to various fields depending on their composition and grade, but are currently being applied to plastic injection products, building reinforcement materials, and packaging bands, which require low technology, and are made into fibers that require a higher level of technology. And product application is insufficient.

In Korea, recycled polyester fiber for clothing using high-purity polyester flakes is being produced mainly by large and medium-sized companies (Hyosung, Huvis, etc.), and nonwoven fabrics for civil engineering and automobiles are being produced mainly by small and medium-sized companies.

Latent crimp fiber is a fiber made by spinning two types of polymers with different heat shrinkage characteristics in a side-by-side or sheath-core manner, then heat shrinking the fiber by applying heat during the spinning or stretching process. It is a fiber that is physically shaped into a coil due to differences in gender, giving it a high degree of elasticity on a principle similar to a spring.

In terms of elasticity, it is not as good as existing spandex fibers, but due to the disadvantages of spandex, latent crimp fibers are widely used, which have excellent alkali resistance and dimensional stability and are easy to dye and post-process.

By composite processing these latent crimped yarns with other types of recycled polyester yarns, composite yarns that meet the needs of more diverse consumers can be manufactured.

In addition, recycled polyester (Recycled Polyester) used in the present invention is a material recycling, recovered raw material in which raw materials are purified from waste materials recovered from waste materials or previously used products during the polyester manufacturing process and then melted and spun to be recycled. It can be divided into Chemical Recycling, which produces yarn by purifying, depolymerizing, and then repolymerizing and melt spinning.

Material Recycle can relatively easily recycle raw materials, but if it is difficult to control the purity and degree of polymerization of the material, it is difficult to obtain a polymer with uniform physical properties, which may limit the expansion of end-use purposes. In the case of Chemical Recycle, it must be reused after depolymerization. Since the polymer is manufactured through polymerization, it has the advantage of being able to produce excellent yarn with little difference in physical properties from yarn made from crude oil.

In the present invention, recycled polyester partially oriented yarn (POY) is manufactured by drying and melt spinning polyester flakes produced by collecting waste plastic under appropriately designed conditions, and this polyester partially oriented yarn (POY) and We intend to manufacture eco-friendly recycled polyester elastic composite yarn using recycled polyester latent crimped yarn.

Prior Document 1: Domestic Patent Application Publication No. 10-2017-0103281 (application published on September 13, 2017) Korean Registration Gazette No. 10-1979655 Korean Registration Publication No. 10-1851644

The present invention was devised to solve the above problems, and manufactures recycled polyester (FD) partially oriented yarn (POY) by drying and spinning recycled polyester resin, and separately manufactured recycled polyester latent crimped yarn. We would like to manufacture eco-friendly recycled polyester elastic composite yarn manufactured by plying yarn.

In general, in order to apply polyester synthetic fiber as a clothing material, it is manufactured to contain a certain amount of matting agent (TiO ₂ ) in order to remove the sparkle of the material itself, and the matting agent is included depending on the content of the matting agent. It is divided into bright (BR: bright), which contains no light (BR: bright), semi-dull (SD: semi-dull), which contains 0.2 to 0.4 wt%, and full-dull (FD), which contains 1.5 to 2.5 wt%, and is applied for each purpose. there is.

In addition, the recycled polyester (FD) partially oriented yarn (POY) is modified to be manufactured by supplying yarn from the composite yarn manufacturing equipment via a separate roll and stretching it using the first roller and the second roller. The goal is to dramatically reduce process defects in composite yarns manufactured and improve the quality of elastic composite yarns.

In order to achieve the above object, the present invention includes the steps of preparing recycled polyester (FD) partially oriented yarn (POY); Preparation stage for recycled polyester-based latent crimped yarn; A yarn supply step of supplying recycled polyester (FD) partially oriented yarn (POY) and recycled polyester latent crimped yarn to the first roller through a ceramic-coated separate roll; A yarn stretching step of stretching each of the yarns between a first roller and a second roller; A heat treatment step of heat treating the stretched yarn in a contact or non-contact heater;

An air-bridging step of forming air-bridging heat-treated yarn with a smart air nozzle; and a winding step of winding the air-interlaced recycled latent crimped composite yarn.

In addition, a method for manufacturing recycled polyester elastic composite yarn is provided, wherein the recycled polyester partially oriented yarn is manufactured at a spinning speed of 2,900 to 3,300 m/min and a fineness of 75 to 85 De'.

In the yarn supply step, the recycled polyester partially oriented yarn (POY) and the recycled polyester latent crimped yarn have a tension of 5 to 7 g between the ceramic coating separate roll and the first roller, and a tension deviation of within ±2 g. A method for manufacturing a recycled polyester elastic composite yarn is provided.

The recycled polyester elastic composite yarn produced in this way is manufactured into fabric through warp knitting and weaving and provided as fabric or knitted fabric for clothing.

Recycled polyester partially oriented yarn (POY) and recycled polyester latent crimped yarn are each supplied using ceramic-coated separate rolls, so the tension of each yarn supplied to the first roller can be maintained and managed at a constant level, preventing process defects. can be significantly reduced.

In addition, it has eco-friendliness, which is a characteristic required by the current clothing material market, and has high price competitiveness through the development of functional materials with excellent elasticity, so the scope of application can be expanded to various clothing materials.

Figure 1 is a manufacturing process flow chart for manufacturing recycled polyester (FD) elastic composite yarn according to the present invention.
Figure 2 is a schematic diagram of a manufacturing apparatus for manufacturing recycled polyester (FD) elastic composite yarn according to the present invention.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings attached to the present invention. In describing the present invention, detailed descriptions of related well-known functions or configurations are omitted in order to not obscure the gist of the present invention.

Figure 1 is a manufacturing process diagram for manufacturing an eco-friendly recycled polyester (FD) elastic composite yarn according to the present invention, and Figure 2 is a schematic diagram of a manufacturing apparatus for an eco-friendly recycled polyester (FD) elastic composite yarn according to the present invention.

The preparation step (S10) of recycled polyester (FD) partially oriented yarn (POY) for manufacturing the eco-friendly recycled polyester elastic composite yarn according to the present invention is to supply the recycled polyester resin to the extruder and extrude the spinning beam. It is manufactured by spinning through a light source.

Referring to Figures 1 and 2, in the recycled polyester partially oriented yarn (POY) preparation step (S10), the recycled polyester partially oriented yarn (POY) is melt-spun through drying and extruder of recycled polyester flakes. It is manufactured. Recycled polyester flakes are purchased and used by collecting waste polyester, separating foreign substances, wet grinding, fractionation, wet grinding, and fractionation. However, in the present invention, recycled polyester flakes have an IV of 0.70 to 0.8 dl/g, a PVC content in the range of 10 to 200 ppm, and a moisture absorption rate of 0.4 to 2% by weight, and are spun by lowering the spinning temperature. By doing so, problems with thread breakage and poor quality can be prevented, and pack filtration conditions can be strengthened to delay the increase in spinning pressure over spinning time.

The recycled polyester flakes undergo a separate drying system (not shown) for crystallization and dehumidification before being supplied to the extruder. The drying system is divided into crystallization drying and dehumidification drying. Crystallization drying is intended to remove moisture and prevent flakes for spinning from fusing together to form bridges, and dehumidifying drying removes moisture inside the flakes. This is because the lower the final moisture content, the fewer defects in the spinning process and the improved physical properties of the recycled polyester yarn.

The dehumidifying drying is carried out for a total of 20 to 60 minutes in the temperature range of 130 to 170 ℃, and the crystallization drying is carried out for 4 to 7 hours at a temperature of 80 to 150 ℃, varying the time for each temperature section, and the final moisture content is 100 ppm. Make sure it is below:

The recycled polyester flakes dried in this way are supplied to the extruder, an extrusion device. The supplied recycled polyester flakes are processed at different temperatures in an extruder with melting zones #1, #2, #3, and #4, depending on the movement path of the polyester resin. must be controlled. In the present invention, each zone is set to a temperature of 280 to 290°C, which can be set to a temperature lower than the spinning melt temperature of 285 to 295°C of general polyester. This is possible because the recycled polyester resin used in the present invention has an intrinsic viscosity of 0.70 to 0.80 dl/g and a melt temperature of 250 to 259°C, which is lower than the intrinsic viscosity and melt temperature of new polyester. It also affects the mechanical properties of elastic composite yarn.

The spinning solution melted in the extruder is spun through a spinning beam to produce recycled polyester (FD) partially oriented yarn (POY) through a spinneret at a spinning temperature of 280 to 290°C. , it is spun at a quenching temperature of 15 to 20°C, and is produced as recycled polyester (FD) partially oriented yarn (POY) by stretching at a constant draw ratio between the first and second rollers. The recycled polyester (FD) partially oriented yarn (POY) manufactured in this way is wound at a winding speed of 2,900 to 3,3000 m/min and a final fineness of 75 to 85 De'.

In order to manufacture recycled polyester (FD) partially oriented yarn by spinning, a matting agent (TiO ₂ ) must be contained in the fiber at 1.5 to 2.5% by weight, which is achieved by using a polyester (FD) masterbatch containing a matting agent (TiO ₂ ). The desired final content ratio can be achieved by manufacturing and inputting it into a melt spinning process, which can be inputted according to a known process.

On the other hand, the recycled polyester-based latent crimped yarn preparation step (S20) uses recycled polyester resins with different viscosities prepared by spinning them using a side-by-side spinning nozzle. The greater the difference in intrinsic viscosity between the two polymers, high-viscosity polyester and low-viscosity polyester, the greater the crimp effect due to the difference in shrinkage, resulting in higher elasticity.

According to FIG. 2, the yarn supply step (S30) of the recycled polyester (FD) partially oriented yarn (POY) and the recycled polyester latent crimped yarn is an improved multi-ply yarn device that is different from the structure of the existing multi-ply yarn device. It is supplied according to the apostle of.

First, the recycled polyester partially oriented yarn (POY) (10) is placed on the creel and then passed through the separate roll (31) and supplied to the first roller (40) via the braided separate roll (33). do. In addition, the recycled polyester-based latent crimped yarn 20 is designed so that it is supplied to the first roller 40 via the separate roll 32 and the braided separate roll 33.

As the yarn is designed in this way, the yarn supply tension of each supplied yarn can be adjusted independently from the influence that occurs when other yarns are supplied. In the existing plied yarn equipment without separate rolls, which corresponds to the comparative example shown in (a) of Figure 2, the tension of the supplied yarn is measured in the range of 5 to 15 g, and the deviation of tension is ±5 g. The fluctuation range within the range was large, resulting in many quality defects. However, depending on the installation of the separate roll 30 as in Examples 6-1 and 2 of the present invention, the yarn tension range measured between the separate roll 33 and the first roller 40 can be managed at the level of 5 to 7 g. and the deviation of tension can be managed at the ±2g level.

As the variation in yarn tension is reduced, hair, loops, etc. that occur on the appearance of the manufactured composite yarn are significantly reduced, and workability and quality uniformity can be further improved.

In the yarn stretching step (S40), the recycled polyester partially oriented yarn (POY) 10 and the recycled polyester-based latent crimped yarn 20 are drawn at the linear speed difference between the first roller 40 and the second roller 70, respectively. This is the stage where it is extended by . In particular, the recycled polyester partially oriented yarn (POY) 10 is drawn at a draw ratio of 1.0 to 1.2 to have a final fineness of 75 to 85 De'.

While being stretched in the yarn stretching step (S40), each yarn simultaneously undergoes a heat treatment step (S50) in which each yarn is heat treated in a contact heater (50) and a non-contact heater (60) on an axle. The heat treatment temperature of the contact heater 50 is in the range of 100 to 160°C, and the heat treatment temperature of the non-contact heater is in the range of 160 to 210°C.

The heat-treated yarn undergoes an air agitation step (S60). Each of the recycled polyester (FD) partially oriented yarn (POY) 10 and the recycled polyester latent crimped yarn 20 that passed through the second roller 70 are braided through air entanglement in the air nozzle 80. do. At this time, the air nozzle 80 used for air agitation supplies air at a pressure within 1.0 to 3.0 kg/m ² to provide air agitation, and the diameter of the air discharge port of the air nozzle is 1.6 to 2.0 mm. The air nozzle 80 used can be selected from a smart air nozzle and a tandem air nozzle. The tandem type has two or more holes through which air is discharged from the nozzle. This can further improve the effect of air circulation, and by introducing an inverter, air at a uniform pressure can be supplied to further improve the mixing ratio.

While the existing nozzle is a method of releasing air at a set pressure from the hole through the air of the air compressor, the smart air nozzle can reduce the deviation of air discharged from the hole by uniformly controlling the air through an electrical signal, thereby maintaining a uniform nip density. It has the advantage of being able to be controlled easily and maximizing the mixing ratio.

The winding step (S70) of the recycled polyester elastic composite yarn is a step of winding the air-interlocked recycled polyester elastic composite yarn at a winding speed of 550 to 850 m/min. The recycled polyester elastic composite yarn produced in this way has a final fineness of 170 to 200 De', strength of 1.8 to 2.2 g/De', and elongation of 15.0 to 25.0%.

The recycled polyester elastic composite yarn of the present invention is manufactured into yarn for fabric production through a twisting process that imparts a twist within the range of 600 to 2000 TM. Fabric manufactured by weaving or knitting the twisted yarn as warp or weft is applied to a conventional one-bath dyeing method in which the fabric is dyed in a high-temperature, high-pressure rapid dyeing machine at 100-130°C for 2-5 hours to produce clothing fabric. can do.

The present invention will be described in detail below through examples. This embodiment is intended to explain the present invention in detail using the most preferred embodiment of the present invention to the extent that a person skilled in the art can easily implement the technical idea of the present invention. The scope is not limited to these examples.

< Example 1-1~1-4> Drying step of recycled polyester resin

Recycled polyester flakes were used with an intrinsic viscosity of 0.70 to 0.80 dl/g, a PVC content of 10 to 200 ppm, a moisture absorption rate of 0.4 to 2.0 wt%, and a melt temperature of 250 to 259°C. Before inputting the drying system, crystallization drying and dehumidifying drying were performed under the conditions of Examples 1-1 to 1-4. Dehumidification drying was performed for 20 to 60 minutes at a temperature range of 130 to 170°C, and crystallization drying was performed at a temperature of 80 to 150°C for a set time for each temperature range.

[Table 1]

The final moisture content and fusion between chips were different depending on the processing time in each temperature range of crystallization drying. When comparing moisture content and bridge generation, Examples 1-3 and 1-4 showed the lowest moisture content. Although this was achieved, no bridges occurred due to fusion.

< Example 2> Recycled polyester Partially oriented yarn ( POY ) Preparation stage (S10)

Recycled polyester flakes dried under the conditions of Example 1 are supplied to an extruder using a feeder, and rapidly cooled at a spinning temperature of 275 to 290°C through an “O” type spinneret. Recycled polyester (FD) partially oriented yarn (POY) was manufactured by adjusting the temperature (Quenching Temp) of 15 to 20°C and the winding speed of 2,900 to 3,3000 m/min as follows.

A polyester (FD) masterbatch containing 30% by weight of TiO ₂ as a matting agent is added to the spinning process using a known method, and the final recycled polyester (FD) partially oriented yarn (POY) containing 1.5% by weight of TiO ₂ is produced. was manufactured.

[Table 2]

Recycled polyester (FD) partially oriented yarn (POY) manufactured under the above conditions has a final fineness in the range of 75 to 85 De', and when comparing the occurrence of defects such as single yarn breakage, weak yarn, appearance defects, hair, and loops during the production process, The process conditions according to Example 2-2 were the best.

< Example 3> to <Example 6> Recycling Manufacture of polyester (FD) elastic composite yarn.

In the composite yarn manufacturing apparatus of FIG. 2, the recycled polyester (FD) partially oriented yarn 10 manufactured according to Example 2 is placed on the creel and passed through the separate roll 31 and the separate roll 33 to the first roller ( 40) was supplied. In addition, the recycled polyester latent crimped yarn 20 is designed to be supplied to the first roller 40 via the separate roll 32 and the braided separate roll 33.

Recycled polyester (FD) partially oriented yarn (POY) 10 and 100De' recycled polyester latent crimped yarn 20 are produced by the difference in linear speed between the first roller 40 and the second roller 70, respectively. The recycled polyester (FD) partially oriented yarn (POY) 10 is stretched at a draw ratio of 1.0 to 1.2 to have a final fineness of 70 to 85 De'.

At the same time as stretching, each yarn is heat treated in a four-way contact heater 50 and a non-contact heater 60, respectively. The heat treatment temperature of the contact heater 50 is in the range of 100 to 160 ℃, and the heat treatment temperature of the non-contact heater is 160 to 160 ℃. Heat treatment is performed in the range of 210°C.

Each recycled polyester partially oriented yarn (POY) 10 and recycled polyester latent crimped yarn 20 that have passed through the second roller 70 are plyed through air entanglement in the air nozzle 80. At this time, the air nozzle 80 used for air agitation supplies air at a pressure within 1.0 to 3.0 kg/m ² to provide air agitation, and the diameter of the air discharge port of the air nozzle is 1.6 to 2.0 mm. The air nozzle 80 used can be a smart air nozzle and a tandem air nozzle, respectively.

The air-interlocked recycled polyester elastic composite yarn is wound at a winding speed of 550 to 850 m/min. The recycled polyester elastic composite yarn produced in this way has a final fineness of 170 to 200 De', strength of 1.8 to 2.2 g/De', and elongation of 15.0 to 25.0%.

<Examples 3-1 to 3-4> Production of recycled polyester (FD) elastic composite yarn according to the yarn speed in the winding step (S70).

[Table 3]

The mixed yarn is a measure of the number of mixed yarns per 1 m of composite yarn and measures the degree of uniformity of two materials. The composite yarn is floated on the surface of water in a water tank and the number of mixed yarns is measured in a length of 1 m. It is 50 mixed yarns per 1 m. If it is more than 40, it is marked as excellent (◎), if it is 40 to 50, it is marked as good ( ○ ), if it is 30 to 40, it is marked as average ( △) , and if it is less than 30, it is marked as poor ( × ).

Productivity evaluation was a relative comparison of the number of defects due to single yarn, thread breakage, and thread deviation during the production process, and was classified as excellent (◎), good ( ○ ), average ( △) , and defective ( × ).

Considering the productivity and the blending degree of the manufactured elastic composite yarn, the yarn speed of 550 to 850 m/min in Example 3-3 was found to be the best.

<Examples 4-1 to 4-3> Characteristics of elastic composite yarn according to heat treatment temperature in heat treatment step (S50).

The color depth, touch, and workability of stretchable composite yarns manufactured by adjusting the temperature range of 100 to 160°C in the contact heat treatment heater (50) under conditions of yarn speed of 550 to 850 m/min according to Example 3-3 were compared.

[Table 4]

When the heat treatment temperature of the contact heater 50 was low, deep coloring after dyeing was found to be low, and when the heat treatment temperature exceeded 140°C, it was confirmed that the Tocch of the elastic composite yarn became harsh and workability deteriorated. Heat treatment performed at a temperature of 140°C was best.

<Examples 5-1 to 5-3> Characteristics of elastic composite yarn according to the air nozzle diameter in the air agitation step (S60).

In the air agitation stage (S50), the air pressure of the air nozzle and the diameter of the air nozzle were compared and evaluated for blending.

[Table 5]

The blending degree was found to be superior the larger the nozzle diameter under the same air pressure conditions, and was confirmed to be the best in the case of Example 5-3 with a diameter of 2 mm.

<Examples 6-1 to 6-2 and Comparative Examples> Comparison of properties of composite yarns according to yarn design

Figure 2 (a) corresponds to a comparative example of the configuration of the yarn of the existing facility, and each recycled polyester (FD) partially oriented yarn (POY) (10) and recycled polyester latent crimped yarn (20) loaded on the creel ) is formed so that each is directly supplied to the first roller 40.

On the other hand, in Example 6-1, the yarn is independently configured so that each yarn is supplied to the first roller 40 via the separate rolls 31, 32, and 33, respectively, so that the yarn is supplied without being influenced by other supplied yarns. Tension management becomes possible. Example 6-2 additionally coated the surfaces of the separate rolls 31, 32, and 33 with ceramic to minimize the surface friction of the separate rolls and minimize frictional heat and wear damage generated from the yarn yarn.

[Table 6]

Appearance, hair, loop, and pimsa evaluations were conducted by measuring the number of occurrences per meter, and scores were given from 1 bad to 5 good. Workability was evaluated by measuring single yarns and thread separation during the process, and scores were given from 1 bad to 5 good. was granted. The wear stability of the guide was assessed by comparing the condition of each guide at the same operating time and giving a score of 1 point for poor to 5 points for good. Quality uniformity was given a score ranging from 1 bad to 5 good by comparing the overall appearance, condition of the mouth, roof, and PIMSA in a relative table.

When comprehensively considering the appearance evaluation, hair, loop occurrence, and workability, it was found that the appearance, quality, and workability were improved by providing a separate roll at the yarn supply stage to reduce the tension error range, especially the separate roll ( 30), it was confirmed that when the frictional force of the yarn was reduced by ceramic coating the surface, the yarn tension was reduced and the error in tension was also reduced, improving the quality of the recycled polyester (FD) elastic composite yarn produced.

Since the recycled polyester elastic composite yarn manufactured under these process conditions has different shrinkage characteristics between the two yarns, it has excellent bulkiness and warmth on the fabric after dyeing, and provides a smooth touch.

10: Recycled polyester (FD) partially oriented yarn
20: Recycled polyester latent crimp yarn
30: Separate Roll
40: First roller (GR ₁ )
50: contact heater
60: Non-contact heater
70: Second roller (GR ₂ )
80: Air nozzle
90: Winding roller

Claims (4)

Recycled polyester (FD) partially oriented yarn (POY) preparation step;
Preparation stage for recycled polyester-based latent crimped yarn;
A yarn supply step of supplying recycled polyester (FD) partially oriented yarn (POY) and recycled polyester-based latent crimped yarn through a ceramic-coated separate roll;
A yarn stretching step of stretching each of the yarns between a first roller and a second roller;
A heat treatment step of heat treating the stretched yarn in a contact or non-contact heater;
An air-bridging step of forming air-bridging heat-treated yarn with a smart air nozzle; and
A method of manufacturing recycled polyester (FD) elastic composite yarn, comprising a winding step of winding air-interlaced recycled latent crimped composite yarn. According to paragraph 1,
The recycled polyester (FD) partially oriented yarn (POY) is manufactured at a spinning speed of 2,900 to 3,300 m/min and a fineness of 75 to 85 De'. According to paragraph 1,
In the yarn supply step, the recycled polyester (FD) partially oriented yarn (POY) and the recycled polyester latent crimped yarn have a tension of 5 to 7 g between the ceramic coated Separate Roll and the Nip Roller, and the tension deviation is within ±2 g. A method for manufacturing recycled polyester (FD) elastic composite yarn, characterized in that: Recycled polyester (FD) elastic composite yarn manufactured by the manufacturing method of any one of claims 1 to 3.