KR20240027907A - Thermal adhesive composite fiber having excellent antibacterial property and soft property and Manufacturing method thereof - Google Patents

Abstract

The present invention relates to a heat-bonded composite fiber and a method of manufacturing the same, and provides a heat-bonded composite fiber with excellent mechanical properties and excellent antibacterial and soft properties, a method of manufacturing the same, and a nonwoven fabric containing the same. It's an invention.

Description

Thermal adhesive composite fiber having excellent antibacterial property and soft property and manufacturing method thereof}

The present invention relates to a heat-sealable composite fiber with high sensitivity such as excellent elasticity and soft touch and excellent antibacterial properties, and a method for manufacturing the same with high mass productivity.

Heat-bonded composite fibers are generally composed of two components, and are widely used in industrial materials because they can easily obtain bulky nonwoven fabrics through adhesion of fibers by melting specific components with heat. Polyester (PET)-based heat-sealable composite fibers are widely used as nonwoven fabrics for filters and household goods such as automobiles, building materials, and sanitary materials.

For example, US Patent No. 4,129,675 introduces a low melting point polyester copolymerized using terephthalic acid (TPA) and isophthalic acid (IPA), and Korean Patent No. 10-1216690. Discloses a low melting point polyester fiber containing isophthalic acid and diethylene glycol to improve adhesion.

However, although the conventional low melting point polyester fibers described above may have spinnability and adhesiveness above a certain level, there is a problem in obtaining a hard-feeling non-woven fabric or fabric structure after heat bonding due to the ring structure of the rigid modifier.

In addition, in order to impart antibacterial properties to the fibers used in the manufacture of non-woven fabrics applied to non-woven products or filters that come in direct contact with the skin, conventionally, when adding an emulsion during fiber manufacturing, antibacterial substances were used together with the emulsion to give anti-bacterial properties to the fiber. Existing antibacterial fibers use antibacterial agents in the emulsion, which increases processing costs due to loss of antibacterial agents during the process, reduces antibacterial activity due to insufficient absorption of antibacterial agents into the fiber, and does not increase the softness of the fiber.

Therefore, there is a need to develop a fiber that can improve the lack of softness of existing heat-bonded fibers, secure excellent antibacterial properties, and have the advantageous physical properties of existing fibers.

US Patent Registration No. US 4129675 (December 12, 1978) Korean Patent Registration No. 10-2061805 (2020.01.03)

The purpose of the present invention was created to solve the above problems. The purpose of the present invention is to provide a heat-sealable composite fiber with excellent mechanical properties as well as excellent touch and antibacterial properties and a non-woven fabric using the same, We aim to provide a method for manufacturing this with high commercial value.

In order to solve the above-mentioned problems, the heat-bonded composite fiber of the present invention is a sheath-core composite fiber including a sheath portion and a core portion, and the sheath portion contains inorganic fine particles and polymers containing zinc oxide and germanium oxide. Contains resin.

As a preferred embodiment of the present invention, the sheath portion may include 0.4 to 2.0% by weight of the inorganic fine particles and the remaining amount of polymer resin.

As a preferred embodiment of the present invention, the inorganic fine particles may contain 92 to 97% by weight of zinc oxide and 3 to 8% by weight of germanium oxide.

As a preferred embodiment of the present invention, the inorganic fine particles may have an average particle diameter of 10 ㎛ or less.

In a preferred embodiment of the present invention, the polymer resin is one or more selected from linear polyethylene, linear low density polyethylene, high density polyethylene, and low density polyethylene. It can be included.

In a preferred embodiment of the present invention, the core portion is a polyester resin containing at least one selected from poly(ethylene terephthalate) and poly(butylene terephthalate), Alternatively, it may include polypropylene resin.

As a preferred embodiment of the present invention, the sheath-core composite fiber may have a fineness of 0.8 to 20 de and a fiber length of 20 to 70 mm.

Another object of the present invention relates to a method of manufacturing the heat-bonded composite fiber described above. After melting each of the chips for the sheath portion and the chip for the core portion, each of the melted resins is composite spun through a composite spinneret to form a sheath-core. Step 1 of manufacturing a type unstretched subtow; Step 2 of stretching the unstretched subtow; 3 steps of applying emulsion and crimping to the stretched tow; and a fourth step of heat setting and cutting the crimped tow. The resin for the sheath part includes inorganic fine particles containing zinc oxide and germanium oxide.

Another object of the present invention is to provide a nonwoven fabric manufactured using the composite fiber.

Another object of the present invention is an application product using the non-woven fabric, such as a top sheet for diapers, a back sheet for diapers, a sheet for sanitary napkins, a filter for an air purifier, a filter for water treatment, a filter for a vacuum cleaner, and a mask. It can be applied to filters and wet tissue materials.

The composite fiber of the present invention has excellent mechanical properties, high crimp count, micro-crimp cycle, and appropriate fluff count, and has excellent antibacterial properties as well as excellent softness, making it suitable for use in non-woven products that come in direct contact with the skin. do.

Hereinafter, the present invention will be described in detail through the method of manufacturing the heat-bonded composite fiber of the present invention.

The heat-bonded composite fiber of the present invention has an antibacterial effect on the sheath portion (sheath component) of the composite fiber itself, unlike the existing case where an antibacterial component was introduced into the emulsion to provide antibacterial properties to the composite fiber when applying an emulsion during the production of composite fiber. It is a composite fiber manufactured to contain specific functional inorganic fine particles.

The heat-bonded composite fiber of the present invention is a first step of manufacturing a sheath-core type unstretched subtow by melting each of the chips for the sheath portion and the chip for the core portion, and then composite spinning each of the melted resins through a composite spinneret. ; Step 2 of stretching the unstretched subtow; 3 steps of applying emulsion and crimping to the stretched tow; It can be manufactured by performing a process including 4 steps of heat setting and cutting the crimped tow.

The chip for the sheath part in the first stage is manufactured by chipping a mixed resin containing inorganic fine particles and polymer resin, and contains 0.4 to 2.0% by weight of inorganic fine particles and the remaining amount of polymer resin, preferably 0.6 to 1.8 weight% of inorganic fine particles. % and the remaining amount of polymer resin, more preferably 0.8 to 1.6 wt% of inorganic fine particles and the remaining amount of polymer resin. At this time, if the inorganic fine particles are less than 0.4% by weight, the produced composite fiber may not have sufficient antibacterial properties, and if it exceeds 2.0% by weight, the friction between the fiber and metal such as the spinneret is reduced during composite spinning, causing a problem of non-uniform spinning properties. There may be.

In addition, the inorganic fine particles contain 92 to 97 wt% of zinc oxide and 3 to 8 wt% of germanium oxide, preferably 93.5 to 97.0 wt% of zinc oxide and 3.0 to 6.5 wt% of germanium oxide, and more preferably It may include 94.5 to 96.5% by weight of zinc oxide and 3.5 to 5.5% by weight of germanium oxide. At this time, if the germanium oxide content is less than 3% by weight, there may be a problem of insufficient softness of the composite fiber, and even if it is used in excess of 8% by weight, the softness is not improved and the antibacterial properties may be reduced, so it is recommended to use within the above range. .

In addition, the inorganic fine particles preferably have an average particle diameter of 10 ㎛ or less, preferably 8.0 ㎛ or less, and more preferably 0.5 to 6.5 ㎛, and if the average particle diameter exceeds 10 ㎛, the inorganic fine particles form composite fibers. Since they are not uniformly dispersed in the sheath, there may be a problem of poor softness and antibacterial properties, and if the average particle size is too small, problems may arise from separation from the fiber during management and fiber manufacturing, so inorganic fine particles with a particle size within the above range are used. It is good to introduce it.

The polymer resin may be a polyethylene resin, and is preferably one or more selected from linear polyethylene, linear low density polyethylene, high density polyethylene, and low density polyethylene. It may include, and more preferably, it may include one or more types selected from linear polyethylene and high-density polyethylene.

In addition, the polymer resin has a melt flow index (MI) of 8 to 25 g/10 min at 190°C as measured by ASTM D 1238, and preferably a melt flow index of 15 to 23 g/10 min (190°C). It is recommended to use one with a melt flow index of 17 to 22 g/10 min (190°C), more preferably, and at this time, if the melt index of the polymer resin is less than 8 g/10 min, an excessive melt temperature must be set by increasing the spinning pressure. There may be a problem of thermal decomposition due to the need for this, and if the melt index of the polymer resin exceeds 25 g/10 minutes, the fiber may be cut during spinning and the quality may deteriorate.

The mixed resin containing inorganic particles and polymer resin used to form chips for sheath parts, that is, the resin for sheath chips, has a melt flow index (MI) of 20 to 30 g/10 min at 190°C, preferably 24 to 30 g/ It may be 10 minutes (190°C), more preferably 25 to 29 g/10 minutes (190°C).

The chip for the core portion is made of poly(ethylene terephthalate) and poly(butylene terephthalate) having an intrinsic viscosity (IV) of 0.5 to 0.9 dl/g as measured by ASTM D2857. It may include a polyester-based resin containing at least one selected type, or a polypropylene resin.

When measured according to ASTM D 1238, the polypropylene resin has a melt flow index of 8 to 20 g/10 min at 230°C, preferably a melt flow index of 10 to 18 g/10 min (230°C). Preferably, the use of a melt flow index of 12.5 to 17.5 g/10 minutes (230°C) is good in terms of controlling the physical properties of uniform fineness and elongation of the fiber.

In step 1, each of the chips for the sheath portion and the chip for the core portion described above are melted by heating to the melting temperature according to each chip material, and then each of the molten resins is composite spun through a composite spinneret to produce a sheath-core type unstretched subtow. manufacture. At this time, the composite spinneret can be a general composite spinneret for manufacturing sheath-core fibers used in the industry.

In addition, in the second stage of stretching, stretched tow can be produced by stretching the unstretched subtow at a stretching ratio of 3.0 to 5.0 times, preferably 3.5 to 4.5 times, and more preferably 4.0 to 4.5 times.

In the third step, an emulsion is applied to the stretched tow, and then a crimping process is performed. The emulsion application is performed to remove static electricity in post-processing, reduce friction, and develop hydrophilic or hydrophobic properties, and is used in the art. It can be performed by a general method, preferably by using an oil roll, spraying method, or dipping method.

Additionally, the crimping process can be performed by applying crimping to the stretched tow using a crimper. The crimped tow that has undergone the crimping process may have a crimping number of 5 to 20 pieces/inch, and preferably a crimping number of 7 to 18 pieces/inch. At this time, if the number of crimps of the crimped tow is less than 5 pieces/inch, there may be a problem that the thickness of the unit weight of the nonwoven fabric decreases, and if the number of crimps of the tow exceeds 20 pieces/inch, there may be a problem of poor uniformity of the nonwoven fabric. .

In step 4, the heat setting may be performed on the crimped tow at 45°C to 130°C, more preferably at 50°C to 120°C, and even more preferably at 55°C to 120°C.

The heat-bonded composite fiber of the present invention manufactured by this method may have a cross-sectional area ratio of the core portion and the sheath portion of 1:0.40 to 2.40, preferably 1:0.50 to 2.00. At this time, if the cross-sectional area ratio of the sheath part to the cross-sectional area of the core part is less than 0.4, there may be a problem of significantly low thermal adhesiveness, and if the cross-sectional area ratio of the sheath part exceeds 2.40, there may be a problem that the mechanical properties of the composite fiber are too low, so it is within the above range. It is desirable to manufacture composite fibers to have a cross-sectional area ratio range of.

The cross-sectional shape of the core portion and/or sheath portion of the composite fiber of the present invention is not particularly limited, and can be manufactured to have various shapes such as circular, oval, pentagonal, square, and triangular shape by adjusting the nozzle shape of the composite spinneret. there is.

In addition, the composite fiber of the present invention may have a fineness of 0.8 to 20 de, preferably 1.0 to 15.0 de, more preferably 1.0 to 10.0 de, and the fiber length may be 20 to 70 mm, preferably 22 to 64 mm, more preferably 1.0 to 10.0 de. Preferably it may be 26 to 50 mm.

In addition, when the composite fiber of the present invention is measured according to ASTM D 3822, the fiber strength may be 2.5 to 5.0 g/de, preferably 2.8 to 4.5 g/de.

The composite fiber of the present invention has excellent antibacterial properties with a bacteriostatic reduction rate of 99.0% or more, preferably 99.5% or more, and the antibacterial properties last for a long time and have excellent softness.

Nonwoven fabrics can be manufactured using the composite fibers of the present invention as heat-bonded fibers, etc., and as a preferred embodiment, the composite fibers can be used to manufacture air through bonding nonwovens and thermal bonding. Nonwoven and/or spunlace nonwoven fabrics can be produced.

In addition, the non-woven fabric can be applied to various application products, for example, a top sheet for diapers, an absorption distribution layer for diapers, a back sheet for diapers, and sanitary napkins. It can be applied to non-woven products used in medical sheets, air purifier filters, water treatment filters, vacuum cleaner filters, mask filters, wet tissues, and construction materials.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples do not limit the scope of the present invention, and should be interpreted to aid understanding of the present invention.

[Example]

Preparation Example 1: Preparation of sheath chip

Inorganic fine particles containing 95.2% by weight of zinc oxide and 4.8% by weight of germanium oxide were prepared. At this time, the inorganic fine particles had an average particle diameter of about 1.5㎛.

Separately, a high-density polyethylene (HDPE) resin with a melt flow index (MI) of 19 to 20 g/10 minutes (190°C) was prepared.

Next, 1.2% by weight of the inorganic particles and the remaining amount of the high-density polyethylene (HDPE) resin were mixed to prepare a resin for a sheath chip with a melt flow index (MI) of 27 g/10 minutes (190°C), and then chipped. A sheath chip was manufactured.

Preparation Examples 2 to 4 and Comparative Preparation Examples 1 to 6

A sheath chip was prepared in the same manner as in Preparation Example 1, except that a resin for a sheath chip having the composition shown in Table 1 below was prepared and then chipped to produce sheath chips, respectively, in Preparation Examples 2 to 4 and Comparative Preparation Examples. 1 to 6 were carried out respectively.

division inorganic particles polymer resin
type Resin for sheath chip
my content Oxidation
zinc Oxidation
germanium average
particle size inorganic particles polymer resin Preparation example 1 96.0
weight% 4.0
weight% 1.5㎛ HDPE resin 1.2% by weight remaining balance Preparation example 2 96.8
weight% 3.2
weight% 1.5㎛ HDPE resin 1.0% by weight remaining balance Preparation example 3 93.5% by weight 6.5
weight% 2.5㎛ HDPE resin 1.0% by weight remaining balance Preparation example 4 96.0
weight% 4.0
weight% 1.5㎛ HDPE resin 1.8% by weight remaining balance Comparison preparation example 1 - - - HDPE resin - remaining balance Comparison preparation example
2 100
weight% - 2.8㎛ HDPE resin 1.0% by weight remaining balance Comparison preparation example
3 97.5
weight% 2.5
weight% 2.4㎛ HDPE resin 1.0% by weight remaining balance Comparison preparation example 4 97.5
weight% 8.5
weight% 3.1㎛ HDPE resin 1.0% by weight remaining balance Comparison preparation example
5 96.0
weight% 4.0
weight% 2.1㎛ HDPE resin 2.2% by weight remaining balance Comparison preparation example 6 96.0
weight% 4.0
weight% 11.2㎛ HDPE resin 1.0% by weight remaining balance

Example 1: Preparation of heat-adhesive composite fiber

(1) Preparation of core chip

A core chip was manufactured by chipping polypropylene (PP) resin with a melt flow index (MI) of 17 g/10 minutes (230°C).

(2) Manufacture of sheath-core composite fiber

The sheath chip of Preparation Example 1 was melted by heating to 240°C, and the core chip was melted by heating to 265°C.

Next, each melted resin was composite spun through a composite spinneret for producing cis-core fibers to produce unstretched subtow.

At this time, the composite spinning was performed under the conditions of a spinning speed of 980 m/min.

Next, the prepared unstretched subtow was stretched at a draw ratio of 4.2 to produce stretched tow.

Next, an emulsion containing a nonionic surfactant and an anionic surfactant is applied to the stretched tow using an oil roll and an oil guide, and then crimped using a crimper. By adding this, a crimped tow with a crimping number of 12 pieces/inch was manufactured.

Next, the crimped tow was heat set at 100°C and cut to produce a heat-sealable sheath-core composite fiber with a fineness of 2de, a fiber length of 38 mm, and a circular cross-section.

At this time, the cross-sectional area ratio of the sheath portion and core portion of the heat-adhesive composite fiber was 1:1.

Examples 2 to 4 and Comparative Examples 1 to 6

Heat-adhesive composite fibers were manufactured using the same core chip and method as in Example 1, but the heat-adhesive composite fibers were manufactured with different sheath chips as shown in Table 2 below, Examples 2 to 4 and Comparative Examples. 1 to 6 were carried out respectively.

Comparative Example 7

Sheath-core composite fibers were manufactured in the same manner as in Example 1 using the sheath chip made from the sheath chip resin of Comparative Preparation Example 1 without the use of inorganic fine particles, except that when an emulsion was applied to the drawn tow, An emulsion containing inorganic fine particles was used.

At this time, the emulsion contains 1.0% by weight of inorganic fine particles, a nonionic surfactant, and an anionic surfactant in the remaining amount. In addition, the inorganic fine particles contained 96.0% by weight of zinc oxide and 4.0% by weight of germanium oxide, and the average particle diameter of the inorganic fine particles was about 1.1㎛.

division Sis part Core part: Sheath part
cross-sectional area ratio Fineness/fiber length Number of windings
(pcs/inch) Example 1 Preparation example 1 1:1 2de/38mm 12 Example 2 Preparation example 2 1:1 2de/38mm 11 Example 3 Preparation example 3 1:1 2de/38mm 13 Example 4 Preparation example 4 1:1 2de/38mm 12 Comparative Example 1 Comparison preparation example 1 1:1 2de/38mm 13 Comparative Example 2 Comparison preparation example 2 1:1 2de/38mm 14 Comparative Example 3 Comparison preparation example 3 1:1 2de/38mm 13 Comparative Example 4 Comparison preparation example 4 1:1 2de/38mm 12 Comparative Example 5 Comparison preparation example 5 1:1 2de/38mm 12 Comparative Example 6 Comparison preparation example 6 1:1 2de/38mm 12 Comparative Example 7 Comparison preparation example 1 1:1 2de/38mm 12

In the production of heat-adhesive composite fibers carried out in the above Examples and Comparative Examples, it was confirmed that Examples 1 to 4, Comparative Examples 1 to 3, and Comparative Example 7 had good spinnability and good uniformity of the fiber, while Comparative Example 4 When the content of germanium oxide in the inorganic particulate component of the sheath chip is increased as shown, and when the inorganic particulate content exceeds 2.0% by weight when manufacturing the resin for the sheath chip as in Comparative Example 5, stickiness occurs intermittently during composite spinning. Therefore, it was difficult to obtain uniform fibers.

In addition, in the case of Comparative Example 6, where the average particle diameter of the inorganic particles used to manufacture the resin for the sheath chip exceeded 10.0㎛, the initial spinnability was good, but the pressure increase rate occurred rapidly, making continuous production of composite fibers difficult. .

Experimental example: Measurement of physical properties

Prepared in the above examples and comparative examples The mechanical properties (strength/elongation), antibacterial property, deodorization, and softness of the sheath-core heat-adhesive composite fiber were measured, and the results are shown in Table 3 below.

(1) Strength and elongation measurements

Fiber strength and elongation were measured based on the ASTM D 3822 evaluation method using a fiber tensile tester from TEXTEXHNO. The number of measurements was 20, and the average values were taken as strength and elongation.

(2) Measurement of antibacterial activity

It was evaluated as bacteriostatic reduction rate (%) according to KS K 0693-2006. The applied strains were Staphylococcus aureus ATCC 6538 and Klebsiella pneumonia ATCC 4352.

(3) Deodorization measurement

Deodorization was measured according to the Japan Textile Evaluation and Technology Council JTETC detection tube method (adsorption to ammonia gas).

(4) Soft touch measurement

For the soft touch evaluation, a blind test was conducted on 5 people who had worked in the field for more than 5 years without sample information, and then the softness of the fabric was evaluated on a scale of 1 to 5, and the average value was rounded to determine the soft touch property. was measured (1 point: very bad, 2 points: bad, 3 points: average, 4 points: good, 5 points: very good).

division robbery
(g/de) believer
(%) antibacterial
(Bacteriostatic reduction rate,%) Deodorizing
(ammonia,%) soft
touchability Staphylococcus aureus pneumoniae Example 1 4.22 102 99.9 99.9 >99 5 Example 2 4.35 103 99.9 99.9 >99 5 Example 3 4.31 102 99.9 99.9 >99 5 Example 4 4.10 115 99.9 99.9 >99 4 Comparative Example 1 4.28 113 5.4 4.8 3.0 3 Comparative Example 2 3.95 111 74.0 72.3 >99 2 Comparative Example 3 3.94 112 90.8 98.1 >99 3 Comparative Example 4 3.76 121 99.9 99.9 >99 5 Comparative Example 5 3.45 142 99.9 99.9 >99 2 Comparative Example 6 3.38 138 99.9 99.9 >99 4 Comparative Example 7 4.25 101 99.9 99.9 >99 2

Through the above examples and experimental examples, it was confirmed that the heat-sealable composite fibers of Examples 1 to 3 were composite fibers with excellent mechanical properties and adhesive strength, as well as high antibacterial properties, deodorization properties, and soft touch properties.

On the other hand, Comparative Examples 1 to 6 showed a tendency for the overall strength to be too low or the elongation to be somewhat high when compared to Examples 1 to 3. In addition, Comparative Example 1, which did not contain inorganic particles in the sheath chip, not only had almost no antibacterial properties, but also showed no deodorizing properties.

In addition, in the case of Comparative Example 3, which was manufactured with a sheath chip with a germanium oxide content of less than 3% by weight in the inorganic fine particles, compared to Example 2, there was a problem in that the softness was greatly reduced.

In addition, compared to Comparative Example 4 and Example 3 manufactured with a sheath chip with a germanium oxide content in the inorganic fine particles exceeding 8% by weight, antibacterial properties, deodorization, and softness are excellent, but as described above, mechanical properties are rather lower. There was a problem.

In addition, in the case of Comparative Example 5, which was manufactured using a sheath chip with an inorganic fine particle content exceeding 2.0% by weight, there was a problem of low mechanical properties and poor softness.

In addition, in the case of Comparative Example 7, the mechanical properties, antibacterial properties, and deodorizing properties were excellent, but the soft properties were poor.

These composite fibers of the present invention are binder fibers, such as air through bonding nonwoven fabric, air-laid nonwoven fabric, thermal bonding nonwoven fabric, spunlace nonwoven fabric, or rate ( Wet laid non-woven fabric can be manufactured, and various antibacterial and high-functional application products can be manufactured using it.

Claims (8)

A sheath-core composite fiber comprising a sheath portion and a core portion,
The sheath portion contains inorganic particles and polymer resin,
The inorganic fine particles are heat-bonded composite fibers with excellent antibacterial properties and softness, characterized in that they contain 92 to 97% by weight of zinc oxide and 3 to 8% by weight of germanium oxide.
The heat-bonded composite fiber with excellent antibacterial properties and softness according to claim 1, wherein the inorganic fine particles have an average particle diameter of 10 ㎛ or less.
The method of claim 1, wherein the sheath portion includes 0.4 to 2.0% by weight of the inorganic fine particles and a remaining amount of polymer resin,
The polymer resin is antibacterial and soft, characterized in that it contains at least one selected from linear polyethylene, linear low density polyethylene, high density polyethylene, and low density polyethylene. Heat-sealable composite fiber with excellent properties.
The method of claim 1, wherein the core portion is made of polyester resin containing at least one selected from poly(ethylene terephthalate) and poly(butylene terephthalate), or polypropylene. A heat-sealable composite fiber with excellent antibacterial properties and softness, characterized by containing (polypropylene) resin.
The heat-bonded composite fiber according to any one selected from claims 1 to 4, wherein the sheath-core composite fiber has a fineness of 0.8 to 20 de and a fiber length of 20 to 70 mm. .
A first step of manufacturing a sheath-core type unstretched subtow by melting each of the chips for the sheath portion and the chip for the core portion and then composite spinning each of the melted resins through a composite spinneret;
Step 2 of stretching the unstretched subtow;
3 steps of applying emulsion and crimping to the stretched tow;
Performing a process including 4 steps of heat fixing and cutting the crimped tow,
The chip for the sheath is a heat-bonded composite fiber with excellent antibacterial properties and softness, characterized in that it contains inorganic fine particles containing zinc oxide and germanium oxide.
A nonwoven fabric comprising the thermally bonded composite fiber of claim 5.
Including the non-woven fabric of paragraph 7,
The nonwoven fabric is characterized in that it is used as a top sheet for diapers, a back sheet for diapers, a sheet for sanitary napkins, a filter for an air purifier, a filter for water treatment, a filter for a vacuum cleaner, a filter for a mask, and wet tissues. product.