KR101775144B1 - Warmth Filler Consisting Of Polyester Complex Hollow Fiber With Excellent Shape Retention And Recovery Rate - Google Patents

Abstract

The present invention relates to a warming filler in which a polyester-based hollow composite filament is packed as a ball shape. The polyester-based hollow composite filament comprises: a polyethylene terephthalate polymer and a polytrimethylene terephthalate polymer as a side by side type. A cross section of the hollow composite filament has an annular shape. A circular hollow unit of 5-30% of the total area is formed in the center of the cross section. The present invention relates to the warming filler using the polyester-based hollow composite filament having an excellent washability (W) value of 2,000 to 9,000 with an excellent shape retention rate (A) and an excellent recovery rate (B). The washability (W)=the shape retention rate (A) the recovery rate (B) (The shape retention rate (A)=1/a weight deviation variability rate (p), the recovery rate (B)=1/a fill power variation rate (q)).

Description

{Warmth Filler Consisting of Polyester Complex Hollow Fiber with Excellent Shape Retention and Recovery Rate}

TECHNICAL FIELD The present invention relates to a warming filler using a polyester-based hollow composite yarn, and more particularly, to a warming filler having excellent shape retention and recovery even after washing several times.

As outdoor clothing becomes popular, when outdoor winds are blowing, everyone can take out the goose down or duck down jumper to maintain the body temperature. Outdoor products are already in the deep part of our life. , Consumers have begun to demand outdoor products that are more suitable for everyday life than high-priced, warm-keeping high-end products for extreme environments.

As a result of these trends, winter outdoor products are being developed for outdoor products that are thin, lightweight, lightweight, windproof, breathable and highly functional outdoor products, and their popularity is increasing day by day.

Unlike outdoor or casual wear, which has a recent characteristic that use of artificial fillers will increase, men's wear with coat-style down products is wool on the outer and duck or goose, The artificial filler is preferred because it is easy to get out, and the unit price is much lower than that of natural filler which is raised in cost. However, a substitute material that can satisfy the warmth and lightweight effect of a feather used as a filler for endothelium is not sufficiently developed.

Most of the cold weather products currently on the market are heat insulation by the air layer, which causes the activity to be lowered as a reason to increase the thickness of the fabric constituting the covering, and the feathers (feather, Is deteriorated due to agglomeration and exudation during washing and it is not good for cosmetics. In addition, the form of pulling feathers from ducks and goosebumps is causing discomfort in animal protection groups. Due to the nature of natural materials, there is a concern that odor is generated, and there are many inconveniences in terms of management such as washing.

Accordingly, in order to satisfy consumer needs of various classes, it is required to develop a general-purpose outdoor product having superior functionality and cost competitiveness, and domestic materials for it.

Korean Patent No. 1183949 discloses a padding for warming which is formed by laminating synthetic fibers and mammalian hairs together. The padding made a multi-layered insulating material made by laminating a synthetic fiber layer, a layer of a mixture of a mammalian hair and a synthetic fiber, and made a formally stable insulating material having a proper thickness without aggregation or fiber exudation. However, The process is troublesome because a separate facility for supplying mammal hair is added, and the merit of the mammal hair is mixed with the synthetic fiber to reduce the merit of the moth, and the price competitiveness is lower than that of a general synthetic thermal insulator.

In addition, Korean Patent No. 1414206 discloses a C-type hollow fiber which has an improved hollow ratio to maximize the effects such as heat insulation and light weight, but it is inconvenient to carry out a post- (IV), and there is no curl property.

In addition, general synthetic fillers are produced in a uniform form by laminating short fibers, and when they are used in clothes such as padding, clustering may occur, and the recoverability is deteriorated when they are used for a long time.

Therefore, it is required to develop a warming filler having excellent shape retention and recovery rate in order to maintain warmth even if it is washed several times for long-term use.

Disclosure of Invention Technical Problem [8] The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a heat insulating filler made of a polyester-based hollow composite yarn having a ball- The purpose is to provide.

It is another object of the present invention to provide a warming filler using a polyester-based hollow composite yarn which can be used in an eco-friendly ball form, which can complement and replace the disadvantages of feather used in clothes.

In order to solve the above-mentioned problems, the present invention provides a method of producing a polyester-based hollow composite yarn comprising a polyethylene terephthalate polymer and a polytrimethylene terephthalate polymer as a side by side type Wherein the hollow composite filament has an annular cross section and a circular hollow portion having a diameter of 5 to 30% of the entire area at the center of the cross section, And a recovery degree (B) of 2000 to 9000. The polyester-based hollow composite yarn according to any one of claims 1 to 7,

Washing degree (W) = Shape maintenance (A) × Recovery (B)

(A) = 1 / weight deviation variation rate (p), recovery degree (B) = 1 / fill power variation rate (q)

The polyethylene terephthalate polymer has an intrinsic viscosity of 0.45 to 0.65 dl / g, and a polytrimethylene terephthalate polymer has an intrinsic viscosity of 1.00 to 1.05 dl / g. A thermosetting filler using a polyester-based hollow composite yarn is provided.

The present invention also provides a thermosetting filler using a polyester-based hollow composite yarn characterized in that the weight ratio of the polyethylene terephthalate polymer to the polytrimethylene terephthalate polymer is 4: 6 to 6: 4. do.

The present invention also provides a warming filler using the polyester-based hollow composite yarn, wherein the polyester-based staple fiber has a draw ratio of 2.1 to 4.0.

In addition, the present invention provides a warming filler using the polyester-based hollow composite yarn, wherein the polyester-based staple fiber has a single fiber fineness of 1.5 to 15 denier and a fiber length of 3 to 100 mm.

The hot-melt filler having a ball shape using the polyester-based hollow composite yarn according to the present invention has a high blending ratio and high elasticity due to the hollow ratio and crimp, The effect is maintained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-section of a fiber of a conventional warm-keeping filler material and a side-by-side two-component composite yarn cross-section through two circular nozzles bonded thereto.
Fig. 2 is a cross-sectional view of a polyester bicomponent composite yarn side-by-side type bicomponent hollow composite yarn used in the present invention.
3 is a conceptual diagram of a cross-section of a side-by-side type bicomponent hollow fiber composite hollow fiber composite yarn used in the present invention.
4 is a cross-sectional view of a spinneret for extruding a side-by-side type bicomponent hollow composite yarn through a melt spinning process, which is a polyester-based hollow composite yarn used in the present invention.
5 is a view showing a ball shape of the warming filler according to a preferred embodiment of the present invention.
FIG. 6 is a graph showing a variation in weight deviation of the warming filler according to the number of washing of the preferred embodiment and the comparative example of the present invention. FIG.
FIG. 7 is a graph showing the fill-power variation of the warming filler according to the number of washes of the preferred embodiment and the comparative example of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, it should be noted that, in the drawings, the same components or parts have the same reference numerals as much as possible. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted so as to avoid obscuring the subject matter of the present invention.

As used herein, the terms " about, " " substantially, " " etc. ", when used to refer to a manufacturing or material tolerance inherent in the stated sense, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-section of a fiber of a conventional warm-keeping filler material, showing a side-by-side two-component composite yarn cross-section through two coupled circular saws. FIG. Refers to a yarn having a Bi-Component structure in which two kinds of polymers having different heat shrinkage components are discharged through a nip and bonded in a side-by-side shape. It has a snowman shape with two circular sections connected to each other. Each circular component is mainly composed of polyethylene terephthalate polymer and polytrimethylene terephthalate polymer. However, since there is no space in the fiber cross section for containing air, there is a problem in heat insulation, elasticity, lightweight, and the like.

FIGS. 2 and 3 are cross-sectional views and a conceptual diagram of a side-by-side type bicomponent hollow fiber composite fiber used in a heat insulating filler according to the present invention.

Wherein the polyester short fibers are aggregated in a ball shape to form a filler, wherein the polyester short fibers are composed of polyethylene terephthalate polymer (110) and polytrimethylene terephthalate polymer (120) The hollow bicomponent composite yarn 100 is a side by side type hollow body having a hollow space 130 at the center thereof.

The bicomponent hollow bicomponent yarn 100 is characterized in that it has wavy or spiral wrinkles.

The polytrimethylene terephthalate (120), which is one component of the bicomponent hollow bicomponent yarn (100), is abbreviated as PTT and is a kind of polyester yarn, It is made good and refers to the skin-friendly yarn. It is a yarn applicable to potential crimp yarns, and has elastic characteristics such as nylon touch and spandex, and is excellent in breathability.

Another component, polyethylene terephthalate (PET) 110, is abbreviated as PET, which is mainly used as synthetic fibers. In general, PET, which is a thermoplastic polymer, is extruded through a spinneret at a temperature higher than the melting point, cooled and solidified, It is used after melt spinning process.

The cross-sectional shape of the hollow composite yarns arranged in the side by side type is an annular shape. The cross-sectional shape of the hollow composite yarn is a ball-shaped heat insulating filler having a circular hollow portion with an area of 5 to 30% .

1, which is a cross-section of a fiber which is a conventional filler, the cross-section of the fiber used in the present invention has a circular hollow space 130 at the center, which can increase the permeability.

Generally, when the enclosure ratio is high, the warmth is excellent. Insulating filler has better heat retention as it contains fibers with lower heat conductivity, and air has the lowest thermal conductivity and is very warm. In addition, the larger the hollow space in the fiber, the more excellent the light weight in addition to the warming property, and the wearer's feeling as a filling material of the garment can be improved.

4 is a cross-sectional view of a spinneret for extruding a side-by-side type bicomponent hollow composite yarn through a melt spinning process with a warming filler fiber according to the present invention.

Further, the above-mentioned two components are extruded through a spinneret at a temperature higher than the melting point to cool and solidify. At this time, although the spinneret has an annular shape as shown in Fig. 4, the spinneret is divided into the first spinneret and the second spinneret at regular intervals.

Molten polyethylene terephthalate polymer is disposed on the upper ends 141 and 151 of each of the first spinneret 140 and the second spinneret 150 and poly The polytrimethylene terephthalate polymer may be eluted. In this process, the volume expands immediately after being extruded at a high pressure, and the distance between the two becomes narrower, resulting in an annular shape that is finally connected.

At this time, in order to obtain a connected annular shape with a narrow spacing, the same polymer should be used at the connection portion. If the separate polymer is eluted by spinneret, interfacial separation between the two polymers may occur, making it difficult to connect the annular shape.

After that, after cooling and solidification process, it becomes undeveloped company. The undrawn yarn thus melt-spun can be made into an end yarn through a stretching process in which the culture and crystallization are expressed in the fiber structure to give the strength to be the final fiber.

The desired fiber and hollow ratio can be obtained according to the size and thickness of the spinneret. On the other hand, when the annular shaped spinneret which is not separated from the beginning is used, the inner radius of the composite yarn is reduced in the process of expanding the volume inside and outside immediately after the high pressure extrusion, so that it may be difficult to have a desired hollow ratio.

FIG. 5 is a view of a ball shape of a warmth filler according to an embodiment of the present invention. FIG. In the bicomponent hollow composite yarn obtained through the spinneret, there is a difference in degree of shrinkage after cooling and solidifying after extrusion due to the difference in intrinsic viscosity of each polymer.

Therefore, a crimp occurs in which the fibers are rounded in accordance with the difference in shrinkage ratio. As the intrinsic viscosity difference becomes larger, the crimp ratio becomes larger and the ball shape can be made small.

Therefore, it is preferable to use a polymer of two components in order to have a large difference in intrinsic viscosity. This is because the polymer of the same component may have a limited range of intrinsic viscosity.

It is preferable that the polyethylene terephthalate polymer used in the present invention has an intrinsic viscosity of 0.45 to 0.65 dl / g and an intrinsic viscosity of 0.9 to 1.1 dl / g of a polytrimethylene terephthalate polymer .

The weight ratio of the polyethylene terephthalate polymer to the polytrimethylene terephthalate polymer is preferably 4: 6 to 6: 4.

The polyester type short fibers of the warm-keeping filler having a ball shape according to the present invention are characterized by a draw ratio of 2.1 to 4.0. Stretching refers to the rearrangement of molecules as they are stretched while being wound in a take-up roller with a fast rotation speed in a slow feed roller.

 Polymeric materials are generally solid, but their mechanical properties are highly dependent on the orientation of the polymer chain. When a polymer in a non-oriented state is stretched in a certain direction at a temperature higher than the second transition temperature, the polymer chains are oriented in the tensile direction thereof and their mechanical properties change. This operation is referred to as elongation, and the synthetic fiber filament spun is easily stretched even by a very small force, and the elongation does not return even if the tension is removed. It is because the polymers are amorphous. Thus, it is not practical as a fiber alone, but if it is stretched above the second transition temperature, the molecules are oriented in the direction of the fiber axis and become extremely elastic fibers.

The polyester-based staple fiber preferably has a monofilament fineness of 1.5 to 15 denier, a fiber length of 3 to 100 mm, and a ball-shaped heat-resistant filler using the staple fiber having a fill power of 250 or more.

Generally, the fill factor and filling power differ depending on the fineness of the staple fibers used in the filler. When the filaments constituting the filler are three or more filaments, the heat resistance may be improved due to the high encapsulation efficiency. However, the filament fibers of the three filaments may be weak in elasticity and the fill power may be deteriorated. It is possible to increase the fill power because of the excellent elastic force, but the permeability can be lowered.

Therefore, the heat-insulating filler having the ball shape of the present invention can satisfy the concave and fill powers simultaneously by using short fibers having a fineness of 2 to 5 denier.

If the fiber length is too short or long, the polyester staple fiber may be difficult to form as a ball type filling material, or the shape stability may be deteriorated. Therefore, it is preferable that the fiber length of the staple fiber is 3 to 100.

In addition, the heat-resistant filler of the present invention is preferably formed in a ball shape so as to have a high filling ratio, excellent elastic recovery property, and a fill power of 250 or more.

Fill power or Filling power is a numerical value indicating how much the down weight (down volume) occupies the down weight. It is one of the value measures of down quality. The larger the fill power, the more amount of air can be filled with the same amount of down, which means that there is a greater amount of air pockets, which results in higher insulation and thermal insulation. Therefore, the higher the fill power is, the better the thermal insulation is.

The following are examples of the method of producing a warming filler having a ball shape and the shape retention (A), recovery (B) and wash wash (W) according to the number of times of washing, and the present invention is limited to the following examples It is not.

(A)

Example 1

The poly (trimethylene terephthalate) polymer was spin-spinned through the spinneret of FIG. 4 with an intrinsic viscosity (IV) of 1.02 and an intrinsic viscosity (IV) of 0.65 of polyethylene terephthalate polymer. The weight ratio of the polymer is 1: 1 and the composite fiber has a stretching ratio of 2.2 after stretching to obtain a composite fiber having a fineness of 3 denier. After that, the fiber is cut to obtain a 24 mm fiber filament. Thereafter, a ball-like warming filler is obtained by using short fibers. 31.5 g of the filler is injected into a 30 cm x 30 cm pouch to a predetermined thickness and then washed. Washing is done by hand washing in 40 ℃ water with neutral detergent. After dehydration, it is completely dried in a well-ventilated space and then divided into nine sections of 10cm × 10cm size flat and flat. Measure the weight of each section.

Example 2

The conditions are the same as those in Example 1, but have a polyethylene terephthalate polymer intrinsic viscosity (IV) of 0.55.

Example 3

The conditions are the same as those in Example 1, except that the polyethylene terephthalate polymer has an intrinsic viscosity (IV) of 0.45.

Comparative Example

The conditions are the same as those of Example 1, except that the binary polymer is polyethylene terephthalate having the same component (IV) of 0.5 and 0.65.

※ Shape maintenance (A) Evaluation method

The shape retentivity indicates the degree to which the filler is transferred to one space after washing several times. It is filled with 31.5g of filler at a constant height in a 30cm x 30cm pouch and divided into 9 equal sections, 3.5g of filler per section After washing 1, 5, 10 and 15 times, weigh the weight of each section again and measure the weight deviation.

The larger the weight deviation, the greater the degree of sticking of the filler. The weight deviations of the sections after 1, 5, 10 and 15 washing of each of the examples and comparative examples were measured and the values are summarized in Table 1 below.

Washing times Example 1 Example 2 Example 3 Comparative Example 1 time 0.094 0.101 0.105 0.115 5 times 0.11 0.121 0.125 0.15 10 times 0.132 0.142 0.148 0.216 15 times 0.163 0.179 0.189 0.31

Table 1 shows weight deviation values according to the number of times of washing in each of Examples and Comparative Examples.

The slope of the differential derivative of the quadratic function is defined as the weight deviation variation rate (p) by plotting the graph of the weight deviation value with respect to the number of washing times (Table 6) and expressing each graph as a quadratic function, Table 2 summarizes.

Weight deviation variation quadratic equation Derivative
Technology machine
(Weight deviation variation rate (p))
(A) Example 1 y = 0.0038x ² + 0.0042x + 0.0862 0.0076 1 / 0.0076 Example 2 y = 0.0042x ² + 0.0042x + 0.0933 0.0084 1 / 0.0084 Example 3 y = 0.0053x ² + 0.0012x + 0.0993 0.011 1 / 0.011 Comparative Example y = 0.0147x ² - 0.0087x + 0.1088 0.030 1 / 0.030

The shape retention (A) is as follows.

(A) = 1 / weight deviation variation rate (p)

It can be seen that as the weight deviation variation rate (p) is larger, the infiltration of the filler increases with an increase in the number of times of washing, and conversely, the infiltration of the infill is less.

6 is a graph showing a variation in weight deviation according to the number of times of washing in Examples and Comparative Examples.

In the comparative example, the weight deviation value is abruptly increased as the number of washing times is increased.

Therefore, it can be seen that the good shape retention (A) can be expressed by the reciprocal of the weight deviation variation rate (p), and the larger the shape retention degree (A), the less the leaching phenomenon of the filler.

Recovery (B)

Example 1

A polytrimethylene terephthalate polymer with a intrinsic viscosity (IV) of 1.02 and an intrinsic viscosity (IV) of 0.65 of a polyethylene terephthalate polymer (IV) was co-spun through the spinneret of FIG. The weight ratio of the polymer is 1: 1 and the composite fiber has a stretching ratio of 2.2 after stretching to obtain a composite fiber having a fineness of 3 denier. After that, the fiber is cut to obtain a 24 mm fiber filament. Thereafter, a ball-like warming filler is obtained by using short fibers. 31.5 g of the filler is injected into a 30 cm x 30 cm pouch to a predetermined thickness and then washed. Washing is done by hand washing at 40 ℃ using neutral detergent. After dehydration, it is dried completely in a well ventilated area and then fill power is measured.

Example 2

The conditions are the same as those in Example 1, but have a polyethylene terephthalate polymer intrinsic viscosity (IV) of 0.55.

Example 3

The conditions are the same as those in Example 1, except that the polyethylene terephthalate polymer has an intrinsic viscosity (IV) of 0.45.

Comparative Example

The conditions are the same as those of Example 1, except that the binary polymer is polyethylene terephthalate having the same component (IV) of 0.5 and 0.65.

◎ Fill power evaluation experiment

 When a sample of 1 ounce (28.4 g) is placed in a cylinder of 241 in diameter and compressed for 3 days at a weight of 3 ounces and then decompressed, the recovered volume is measured. For example, if the recovered volume is 300 in3 / oz Fill power 300, and calculate the average value of five evaluation tests per sample.

※ Recovery rate (B) Evaluation method

The recovery degree (B) shows the degree of recovery of the filler volume after washing several times. 31.5 g of the filler was filled in a 30 cm x 30 cm pouch flat at a constant height, and then washed at 1,5,10 and 15 times The recovery value (%) of the initial fill power value was measured by measuring the post-fill power. The values are summarized in Table 3 below.

Washing times Example 1 Example 2 Example 3 Comparative Example 1 time 98.00% 97.30% 97.00% 95.30% 5 times 96.75% 95.90% 95.32% 93.80% 10 times 94.00% 92.40% 91.50% 87.20% 15 times 89.00% 86.20% 83.90% 78.50%

Table 3 shows the fill power recovery rate (%) according to the number of times of washing in each of the examples and the comparative examples.

The graph shows the fill power recovery rate (%) for the number of washes (Table 3), and the graph is expressed as a quadratic function to calculate the absolute value of the slope of the derivative derivative of the quadratic function as the fill power variation rate (q) And the values are summarized in Table 4.

Fill power variation quadratic equation Derivative
Descriptor absolute value
(Fill power variation rate (q))
Recovery (B) Example 1 y = -0.0094x ² + 0.0171x + 0.9719 0.019 1 / 0.019 Example 2 y = -0.012x ² + 0.0232x + 0.9615 0.024 1 / 0.024 Example 3 y = -0.0148x ² + 0.0309x + 0.9531 0.030 1 / 0.030 Comparative Example y = -0.018x ² + 0.033x + 0.9395 0.036 1 / 0.036

Recovery rate (B) is shown in the following equation.

Recovery rate (B) = 1 / fill power variation rate (q)

The larger the fill power variation ratio (q), the smaller the recovery of the volume of the filler as the number of washing times increases.

7 is a graph showing variation of fill power according to the number of times of washing in the examples and the comparative examples.

In the comparative example, the fill-up recovery rate (%) is drastically lowered as the number of times of washing is increased.

Therefore, the goodness of recovery (B) can be expressed as the reciprocal of the fill power variation rate (q).

The shape maintenance chart (A) and the recovery chart (B) are numerical values defining whether the initial shape is maintained even after washing the filler of the present invention many times. It is known that the larger the value is, the better the initial shape is maintained . Therefore, the value of the wash rate W can be defined by the following equation using the values of the two variables.

Washing degree (W) = Shape maintenance (A) × Recovery (B)

My laundry (W) (A) Recovery (B) Example 1 6925 1 / 0.0076 1 / 0.019 Example 2 4960 1 / 0.0084 1 / 0.024 Example 3 3030 1 / 0.011 1 / 0.030 Comparative Example 926 1 / 0.030 1 / 0.036

Table 5 shows the value of the washing degree (W), which is 3000 to 7000 in the examples and 1000 or less in the comparative example. Therefore, the washability W is preferably 1000 or more, more preferably 2000 to 9000, so that the function as a warming filler can be maintained even when washing is repeated several times. 9000 or more, it may be difficult to manufacture the hollow fiber composite fiber due to the viscosity difference of the two components.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. It will be clear to those who have knowledge of.

100: Binary hollow composite yarn
110: polyethylene terephthalate polymer
120: polytrimethylene terephthalate polymer
130: hollow (empty space)
140: first spinneret 141: first spinneret top
143: first spinneret bottom 150: second spinneret
151: second spinneret top 153: second spinneret bottom

Claims (5)

A polyethylene terephthalate polymer and a polytrimethylene terephthalate polymer are spun through two symmetrical spinnerets of an annular shape bisecting at regular intervals to form a side by side type poly As a heat-resistant filler in which ester-based hollow composite fibers are bundled in a ball shape,
Wherein each of the symmetrical spinnerets is characterized in that a polyethylene terephthalate polymer and a polytrimethylene terephthalate polymer are spatially separated and emitted to the same polymer at regular intervals therebetween ,
The cross-section of the hollow composite yarn is annular in shape, and a circular hollow portion having 5 to 30% of the total area is formed at the center of the cross-
A warming filler using a polyester hollow composite yarn having a washability (W) value of 3000 to 7000, which is excellent in shape retention (A) and recovery (B)

Washing degree (W) = Shape maintenance (A) × Recovery (B)
(A) = 1 / weight variation rate (p), 90 to 140,
Recovery rate (B) = 1 / fill-power variation rate (q), 30 to 60)
The method according to claim 1,
Wherein the polyethylene terephthalate polymer has an intrinsic viscosity of 0.45 to 0.65 dl / g, and the polytrimethylene terephthalate polymer has an intrinsic viscosity of 1.00 to 1.05 dl / g. Thermosetting filler using composite yarn.
The method according to claim 1,
Wherein the weight ratio of the polyethylene terephthalate polymer to the polytrimethylene terephthalate polymer is 4: 6 to 6: 4. 4. The thermoplastic filler as claimed in claim 1, wherein the weight ratio of the polyethylene terephthalate polymer to the polytrimethylene terephthalate polymer is 4: 6 to 6: 4.
The method according to claim 1,
Wherein the polyester-based hollow composite filament yarn has a stretching ratio of 2.1 to 4.0.
The method according to claim 1,
Wherein the polyester-based hollow composite sintered fiber has a single fiber fineness of 1.5 to 15 denier and a fiber length of 3 to 100 mm.

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