KR20230096549A - Method for manufacturing thermal adhesive fiber web and thermal adhesive fiber web manufactured therefrom - Google Patents

Abstract

A method for manufacturing a thermally adhesive fiber web is provided. A thermally adhesive fiber web according to one embodiment of the present invention is prepared by the steps comprising: (1) preparing a first spinning solution in which a first polymeric compound, which is a support component, is dissolved, and a second spinning solution in which a second polymeric compound, which is a thermal bonding component, having a melting point at least 50℃ lower than a melting point of the first polymeric compound, is dissolved; (2) transferring the first spinning solution and the second spinning solution through different flow paths such that the spinning solutions are not blended until an end of a discharge port of one nozzle of an electrospinning device, and then electrospinning the first spinning solution to be discharged through a part of an end surface of the discharge port and the second spinning solution to be discharged through the remaining part of the end surface of the discharge port to accumulate side-by-side thermally adhesive composite fibers having a diameter of less than 1 ㎛; and (3) applying heat to the accumulated side-by-side thermally adhesive composite fibers to produce a thermally adhesive fiber web. Accordingly, the present invention is suitable for manufacturing a thermally adhesive fiber web that allows easy interfacial bonding to dissimilar materials having different material and structural specifications while preventing closure of initially retained pores during thermal bonding, since the fiber web itself possesses thermally adhesive properties.

Description

Method for manufacturing thermal adhesive fiber web and thermal adhesive fiber web manufactured therefrom

The present invention relates to a method for manufacturing a heat-sealable fibrous web and a heat-sealable fibrous web manufactured thereby.

In general, electrospinning is a method of producing nanofibers through an electric field formed by applying an electric field to a polymer solution. Specifically, as the surface tension of the polymer solution is overcome by the electric field applied to the spinneret, the discharged polymer solution forms a jet, and this jet flies to the collector by a whipping mechanism, thereby dissolving the solvent. With volatilization, the polymer solidifies to form a fibrous structure.

The electrospun nanofibers manufactured through the above method are fused and combined with woven fabrics, non-woven fabrics, knits, and papers, and are applied to filters, moisture-permeable and waterproof materials, separators for various batteries, biomedical materials, and vents for electronic devices. there is.

At this time, the convergence process of nanofibers and heterogeneous materials having different material and / or structural specifications, such as woven fabrics and nonwovens, is performed through processing such as fusion or calendering through heat or ultrasonic waves using adhesives or binders. . However, the use of a separate binder or hot melt material results in clogging of the pores of the web formed of nanofibers, resulting in reduced air permeability, and there is a problem in that the excellent physical properties of the web formed of nanofibers cannot be sufficiently expressed. In addition, the use of separate adhesives or hot melt materials accompanies the addition of materials and processes, ultimately adversely affecting carbon emissions and energy.

In order to solve this problem, research has been conducted on blending two polymer compounds with different melting points and electrospinning so that the nanofibers manufactured through electrospinning can be self-welded without a separate adhesive or hot melt material, but most of the polymer compounds for electrospinning It is difficult to obtain uniformly blended nanofibers due to phase separation due to poor compatibility between heterogeneous materials.

In addition, in order to solve this problem, in recent years, woven or nonwoven fabrics that are converged with nanofibers are made of sheath-core type low-melting composite fibers or configured to contain some low-melting composite fibers to achieve convergence with nanofibers. Attempts are continuing, but it is difficult to achieve interfacial adhesion between nanofibers and conventional low-melting composite fibers, so that nanofibers are partially separated from the fusion composite, or woven or nonwoven fabrics used in the fusion composite are made only with low-melting composite fibers. There is a problem in that there is a limitation in the selection of woven fabric or nonwoven fabric because there is no choice but to use it.

Publication No. 2009-0111230

The present invention has been devised in consideration of the above points, and since the fiber web itself has thermal adhesiveness without a separate adhesive or hot melt material, it is possible to easily perform interfacial bonding to dissimilar materials having different materials and structural specifications through thermal fusion. It is an object of the present invention to provide a method for manufacturing a heat-sealable fibrous web and a heat-sealable fibrous web produced through the method.

In addition, the present invention exhibits excellent thermal bonding performance while preventing the closure of pores possessed in the initial application during interfacial thermal bonding with different materials, so that the initial properties such as air permeability and water pressure resistance of the thermal bonding fiber web are intact even after interfacial thermal bonding And another object is to provide a heat-sealable fibrous web that is expressed.

In order to solve the above problems, the present invention is (1) the first spinning solution in which the support component, which is the first polymer compound, is dissolved, and the thermal bonding component, which is the second polymer compound, which has a melting point at least 50 ° C lower than that of the first polymer compound, is dissolved. Step of preparing the second spinning solution, (2) transferring the first spinning solution and the second spinning solution to the end of the discharge port of one spinning nozzle of the electrospinning device to the end of the discharge port after transferring the first spinning solution and the second spinning solution through different channels so that the spinning solutions are not blended Accumulating side-by-side heat-sealable composite fibers having a diameter of less than 1 μm by electrospinning such that the first spinning solution is discharged to a certain portion of the cross section and the second spinning solution is discharged to the remaining portion, and (3) ) It provides a heat-sealable fibrous web manufacturing method comprising the step of preparing a heat-sealable fibrous web by applying heat to the accumulated side-by-side heat-sealable composite fibers.

According to one embodiment of the present invention, the first spinning solution and the second spinning solution may contain the same kind of solvent.

In addition, the first polymer compound includes at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polybenzyl imidazole (PBI), and high melting point polyethersulfone (PES), and the second polymer compound may include at least one of low melting point polyethersulfone and polyvinyl butyral.

In addition, the solvent may be any one or more solvents of dimethylformamide and dimethylacetamide, or a solvent in which acetone or alcohol is mixed with any one or more solvents of dimethylformamide and dimethylacetamide.

Also, in step (3), heat may be applied at a temperature higher than the glass transition temperature and lower than the melting point of the second polymer compound.

In addition, the present invention is a side-by-side having a diameter of less than 1 μm in which a support part formed of a first polymer compound in a cross section and a heat-sealed part formed of a second polymer compound having a melting point at least 50 ° C lower than that of the first polymer compound are adjacently disposed. Provided is a heat-sealable fibrous web having a three-dimensional network structure in which heat-sealable composite fibers are accumulated and welded between surfaces of the composite fibers in contact.

According to one embodiment of the present invention, the area of the thermally bonded portion in the cross-section of the heat-sealable composite fiber may be 50% or less of the cross-sectional area.

In addition, the area of the thermal bonding portion may be 10 to 30% of the cross-sectional area.

In addition, the first polymer compound may include polyvinylidene fluoride, and the second polymer compound may include polyvinyl butyral.

In addition, the present invention has a diameter of less than 1 μm, and in a cross section, a support part formed of a first polymer compound and a thermal bonding part formed of a second polymer compound having a melting point at least 50 ° C lower than that of the first polymer compound are disposed adjacent to each other. -Provides side-type heat-sealable composite fibers.

In addition, a sound-permeable sheet for waterproofing and dustproofing having the heat-sealable fibrous web according to the present invention is provided.

The method for manufacturing a heat-sealable fibrous web according to the present invention can realize a side-by-side type heat-sealable fiber in which separation does not occur at the interface formed by adjacently spun two types of polymer compounds, and through this, separate As the fibrous web itself has heat-adhesiveness without adhesives or hot-melt materials, it is suitable for realizing a heat-sealable fibrous web capable of interfacial bonding to dissimilar materials having different material and structural specifications through easy heat-sealing. In addition, the heat-sealable fibrous web manufactured according to the present invention exhibits excellent heat-sealing performance while preventing the closure of pores initially held during interfacial thermal bonding with a different material, thereby improving air permeability and water resistance possessed by the heat-sealable fibrous web. Since the initial physical properties can be fully retained and expressed even after interfacial thermal bonding, it can be used as a thermal bonding member or itself can be widely used for various purposes, such as membranes for water treatment or membranes for electronic devices.

1 is a schematic diagram showing an electrospinning process included in an embodiment of the present invention;
2a to 2c are cross-sectional schematic views of side-by-side heat-sealable composite fibers according to various embodiments of the present invention;
Figures 3a and 3b are schematic diagrams at the interface of convergence with different materials, and Figure 3a is a schematic diagram showing thermal bonding at the interface between a heat-sealable fibrous web and a different material according to an embodiment of the present invention, Figure 3b is a schematic diagram showing thermal bonding through a hot melt agent at the interface between a non-thermal bonding fiber web and a different material;
4 is a scanning electron micrograph of side-by-side thermally adhesive composite fibers accumulated after electrospinning in the process of manufacturing a thermally adhesive fibrous web according to Example 1, (a) magnification 5,000 times, (b) 10,000x magnification photo,
5 is a scanning electron micrograph of a heat-sealable fibrous web prepared according to Example 1, including (a) a surface and (b) a cross-sectional photograph, and
6 is a scanning electron micrograph of a heat-sealable fibrous web prepared according to Example 2 (a) at 5,000 times magnification and (b) at 30,000 times magnification.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. This invention may be embodied in many different forms and is not limited to the embodiments set forth herein. In order to clearly describe the present invention in the drawings, parts irrelevant to the description are omitted, and the same reference numerals are added to the same or similar components throughout the specification.

A heat-sealable fibrous web according to an embodiment of the present invention includes: (1) a first spinning solution in which a support component, which is a first polymer compound, is dissolved; Preparing the second spinning solution in which the adhesive component is dissolved, respectively, (2) the first spinning solution and the second spinning solution are passed through different channels to the end of the discharge port of one spinning nozzle of the electrospinning device so that the spinning solutions are not blended. After transferring, electrospinning is performed so that the first spinning solution is discharged to a part of the end surface of the discharge port and the second spinning solution is discharged to the remaining portion, thereby accumulating side-by-side heat-sealable composite fibers having a diameter of less than 1 μm. and (3) preparing a heat-sealable fibrous web by applying heat to the accumulated side-by-side heat-sealable composite fibers.

As step (1) according to the present invention, the first spinning solution in which the support component, which is the first polymer compound, is dissolved, and the second polymer compound, which is the second polymer compound, in which the melting point is at least 50 ° C. lower than that of the first polymer compound, the thermal bonding component is dissolved. Each step of preparing the spinning solution is performed.

The support component is a component that performs a support function in the spun side-by-side heat-sealable composite fibers and the heat-sealable fiber web realized by them. In addition, the thermal bonding component is a component that exhibits thermal bonding characteristics between side-by-side thermally bonding conjugate fibers or at an interface between these conjugate fibers and a different material.

These support components and thermal bonding components may be used without limitation when a combination of polymer compounds having a melting point difference of 50° C. or more among known polymer compounds known to be generally electrospinable is used. In addition, the same type of polymer compound having a melting point difference of 50° C. or more may also be used as a support component and a thermal bonding component, respectively. If the melting point difference is less than 50 ° C., it may be difficult to achieve the object of the present invention, such as weakening the thermal adhesiveness at the interface. In addition, the melting point difference may be preferably 100 ℃ or less. In addition, as an example, the supporting component is high melting point (or high polymer) polyurethane, polyacrylonitrile (PAN), polyetherimide (PEI), polymethyl methacrylate, polyvinyl chloride (PVC), polycarbonate ( A first polymer compound comprising at least one selected from the group consisting of PC), polyethylene terephthalate, polyamide, polyvinylidene fluoride (PVDF), polybenzyl imidazole (PBI), and high melting point polyethersulfone (PES) can be

In addition, the heat sealing component is low melting point (hypopolymer) polyurethane, polystyrene (PS), polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), polylactic acid (PLA), polyethylene oxide (PEO), poly Vinyl acetate (PVAc), polyacrylic acid (PAA), polycaprolactone (PCL), polyvinyl fluoride (PVDF), polyvinylpyrrolidone (PVP), polyacrylonitrile (PAN), polycarbonate (PC) , It may be a second polymer compound containing at least one of low melting point polyethersulfone and polyvinyl butyral.

Preferably, the first polymer compound includes at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polybenzyl imidazole (PBI) and high melting point polyethersulfone (PES), and the second polymer compound A side-by-side composite fiber can be implemented with a combination containing at least one of low-melting polyethersulfone and polyvinylbutyral, and more preferably, the first polymer compound includes polyvinylidene fluoride, , The second polymer compound may include polyvinyl butyral, which may be advantageous in achieving the object of the present invention.

The above-described first polymer compound and the second polymer compound are each dissolved in a solvent to form a first spinning solution and a second spinning solution. If homogeneous or heterogeneous polymer compounds with different melting points are mixed and the ratio of polymer compounds with low melting points is increased when spinning with a single spinning solution, the ratio exposed to the surface of the spun fiber is not uniform, and in addition, the ratio exposed to the surface is small. It is better not to mix these two spinning solutions until just before spinning.

The first spinning solution and the second spinning solution may include a solvent capable of dissolving the first polymer compound and the second polymer compound, respectively. The solvent is suitable for dissolving the selected polymer compound, and may be used without limitation in the case of a known solvent used in the preparation of a spinning solution for electrospinning. For example, the solvent contained in the first spinning liquid and the solvent contained in the second spinning liquid are each independently in any one or more solvents of dimethylformamide and dimethylacetamide, or any one or more solvents of dimethylformamide and dimethylacetamide. A solvent mixed with acetone or alcohol may be used.

However, preferably, the solvents used for each of the first spinning solution and the second spinning solution may be of the same kind, and further substantially the same solvent. If the same or even substantially the same solvent is not used, the solidification that occurs when the two spinning solutions meet each other at the tip of a single spinning nozzle causes clogging of the spinning nozzle or deterioration in spinning performance, and side-by-side composite fibers are realized. Even in this case, the area formed of the first polymer compound and the area formed of the second polymer compound can be implemented to have an area ratio different from the area ratio designed in the initial drawing, so that it does not have sufficient thermal bonding performance or the pores are closed after thermal bonding. can

In addition, the first spinning solution and the second spinning solution preferably contain the first polymer compound and the second polymer compound at 10 to 30% by weight, preferably 10 to 20% by weight, respectively, and if less than 10% by weight In this case, during spinning, it may be sprayed in the form of droplets instead of fibers, and even if spinning is performed, many beads are formed and the solvent is not evaporated well, which may cause pores to be clogged in the calendering process described later. In addition, if the fiber-forming component exceeds 30% by weight, the viscosity increases and solidification occurs on the surface of the solution, making it difficult to spin for a long time, and the fiber diameter increases, making it difficult to manufacture composite fibers having a diameter size of less than a micrometer.

Next, as step (2) according to the present invention, (2) the first spinning solution and the second spinning solution are transferred to different flow paths so that the spinning solutions are not blended to the end of the discharge port of one of the spinning nozzles of the electrospinning device Side-by-side heat-sealable composite fibers having a diameter of less than 1 μm are accumulated by electrospinning such that the first spinning solution is discharged to a part of the end surface of the discharge port and the second spinning solution is discharged to the remaining portion. do.

Referring to FIG. 1, the first spinning solution is provided in the first flow path 31, the second spinning solution so that the first spinning solution and the second spinning solution do not meet until the end of the discharge port of any one spinning nozzle 30 in the electrospinning device. After being transported through the second flow path 32, the used liquid is electrospun on the current collector 40 so that the first spinning liquid is discharged to a certain part of the end surface of the discharge port and the second spinning liquid is discharged to the remaining part. The side-by-side heat-sealable composite fibers may be accumulated on the current collector 40 . In addition, as an example of the spinning nozzle, as shown in FIG. 1, a spinning nozzle having a Y-shaped cross section may be used.

In addition, the electrospun side-by-side heat-sealable composite fiber may have a diameter of less than 1 μm, preferably 100 to 700 nm, and the heat-sealable fiber web realized through this exhibits excellent water pressure resistance characteristics and It can be advantageous in terms of thermal bonding performance as the interface in contact with different materials to be fused and combined increases.

On the other hand, composite fibers having a cross-section of sheath-core type can also be implemented through a single spinning nozzle divided into different parts of the end surface of the discharge port, that is, the core part and the sheath part surrounding it, but to manufacture sheath-core type composite fibers Spinning nozzles for side-by-side type composite fibers are more complicated than spinning nozzles for producing side-by-side composite fibers, and even when the ejection area is designed differently during spinning, low-melting polymer compounds may not be exposed to the outside, and different types of polymers The area of the interface in contact with the compound is larger than that of the side-by-side type composite fiber, and there is a concern that separation between regions formed of heterogeneous polymer compounds may occur. In addition, the fibrous web in which the spun sheath-core type thermally adhesive composite fibers are accumulated has a problem of frequent pore blockage during thermal compression.

On the other hand, in the case of a heat-sealable fibrous web in which support fibers and heat-sealable fibers are mixed, which are produced by spinning the first and second spinning solutions through different spinning nozzles, the support fibers and the heat-sealable fibers are uniformly distributed. It may not be mixed, and the ratio of heat-sealable fibers exposed to the outside of the heat-sealable fibrous web may not be uniform, so the heat-sealability is insufficient or partially insufficient at the interface with the different materials to be converged. This type of heat-sealable fibrous web may also be undesirable compared to a heat-sealable fibrous web formed in which side-by-side heat-sealable composite fibers are accumulated.

The step (2) can use a conventionally known electrospinning apparatus, and the electrospinning conditions can also be performed within a known condition range in consideration of the type of polymer compound selected, so the present invention is not particularly limited thereto. For example, the discharge amount of each spinning solution is 0.01 to 5 cc/g per minute for each spinning nozzle independently, the applied voltage is 0.5 kV to 100 kV, the air gap, which is the distance from the nozzle to the current collector, is 5 to 50 cm, and the spinning atmosphere is relative humidity 20 ~ 80%, the temperature may be 20 ~ 40 ℃.

Next, as step (3) according to the present invention, heat is applied to the accumulated side-by-side heat-sealable composite fibers to prepare a heat-sealable fibrous web.

Step (3) is performed so that the heat-sealable fibrous web has a three-dimensional network structure and has a desired porosity, pore diameter, basis weight, etc. Heat and pressure may be applied to realize a heat-sealable fibrous web. The heat or heat and pressure may be performed through a known device, for example, calendering. At this time, the applied heat may be applied at a temperature higher than the glass transition temperature of the second polymer compound and lower than the melting point, and specific Since the temperature varies depending on the type of the second polymer compound selected, the present invention is not particularly limited thereto. For example, when the first polymer compound is polyvinylidene fluoride and the second polymer compound is polyvinyl butyral, the applied temperature may be 70 to 130 °C.

In addition, when performing the calendering process, it may be performed once or multiple times, for example, after performing a drying process to remove the solvent remaining in the fiber through primary calendering, 2 Tea calendering can be carried out. In this case, the degree of heat and/or pressure applied in each calendering process may be the same or different.

As shown in FIGS. 2A to 2C , the heat-sealable fibrous web manufactured through the above-described manufacturing method includes a support portion 10 formed of the first polymer compound in the cross section and a melting point lower than that of the first polymer compound by at least 50 ° C. Side-by-side heat-sealable composite fibers (100, 101, 102) having a diameter of less than 1 μm, in which heat-sealed portions 20 formed of two polymer compounds are adjacently disposed, are accumulated, and three-dimensional welded between the surfaces of the heat-sealable composite fibers in contact. have a network structure.

As shown in FIG. 3A, the heat-sealable fibrous web can be welded (A) at the interface formed with the fibers 200 in the heterogeneous material in which the heat-sealable composite fibers 100 are fused and fused. And there is an advantage that can be thermally bonded without affecting the pores of both materials. However, as shown in FIG. 3B, in the case of the non-thermal adhesive fiber 400 having the same diameter as the thermally adhesive composite fiber, a separate adhesive or hot melt agent 400 is required to bond with the fiber 200 in a different material, The hot melt agent 400 may change the pores of both the heat-sealable fibrous web and the different materials.

Preferably, the area of the thermally bonded portion 20 in the cross section of the heat-sealable composite fibers 100 and 101 may be 50% or less of the cross-sectional area, and if the area of the thermally bonded portion 20 exceeds 50%, the heat-sealable fibrous web Pores may be clogged during the manufacturing process or during the thermal bonding process with different materials to be converged. More preferably, the area of the thermal bonding portion 20 may be 10 to 30% of the cross-sectional area, and through this, the bonding performance can be greatly improved through line contact with a different material to be converged. However, when the thermal bonding portion 20 contains less than 10%, it is not preferable because there is a concern that the thermal bonding performance is greatly reduced.

On the other hand, the area of the thermally bonded portion in the cross section of the thermally adhesive composite fiber can be realized by adjusting the concentration of the polymer compound in the first spinning solution and the second spinning solution, and the supply speed.

The heat-sealable fibrous web described above may have a thickness of 10 to 100 μm, but is not limited thereto.

In addition, the heat-sealable fibrous web may be used to manufacture a sound-permeable waterproof sheet. The sound-permeable waterproof sheet may include layers provided in known sound-permeable waterproof sheets such as a water repellent layer, a waterproof layer, a sound layer and a protective layer, and the heat-sealable fiber web according to an embodiment of the present invention is a waterproof and dustproof layer and / Alternatively, it can be used as an acoustic layer. On the other hand, for specific examples of the sound-permeable waterproof sheet, Application No. 10-2019-0151233 and Application No. 10-2021-0021153 by the same applicant of the present invention are inserted as references in the present invention.

Although the present invention will be described in more detail through the following examples, the following examples are not intended to limit the scope of the present invention, which should be interpreted to aid understanding of the present invention.

<Example 1>

It is prepared by dissolving polyvinylidene fluoride (PVDF) as the first polymer compound, which is a support component, in a mixed solvent of DMAc (dimethylacetamide) / Acetone (mixing ratio 80:20 in weight%) so that it is 15% by weight relative to the total weight of the spinning solution. 1 spinning solution was prepared. In addition, polyvinyl butyral (PVB), which has a melting point lower than that of the first polymer compound by about 100 ° C, is mixed with DMAc (dimethylacetamide) / Acetone (the mixing ratio is 80:20 in weight %) as a second polymer compound, which is a thermal bonding component. A second spinning solution was prepared by dissolving to be 15% by weight relative to the total weight of the spinning solution.

The prepared first spinning solution and the second spinning solution are transferred to a spinning nozzle pack, and each using a metering pump through the first flow path 10 and the second flow path 11 in one spinning nozzle 30 in FIG. Electrospinning was performed in a radiation atmosphere with a discharge amount of 0.05 cc/ghole per minute, an applied voltage of 20 kV, a distance between the spinning nozzle tip and the current collector of 20 cm, a temperature of 30 ° C and a relative humidity of 60%, and the average diameter as shown in FIG. A side-by-side composite fiber having a thickness of about 500 nm and an area of 50:50 between the support portion and the thermally bonded portion was prepared. The prepared side-by-side composite fibers are thermally fused between the heat-sealable composite fibers through a roller heated to 120 ° C, which is between the glass transition temperature and the melting temperature of PVB, so that the interfacial bonding between the heat-sealable composite fibers is achieved. Thus, a heat-sealable fibrous web having an average thickness of 45 μm as shown in FIG. 4 was obtained.

Through FIG. 4, it can be confirmed that the thermally adhesive composite fibers were smoothly interfacially bonded between the composite fibers by surface thermal welding, and the variation of pores was small with the naked eye.

<Example 2>

It is prepared in the same manner as in Example 1, but the supply speed of the first spinning solution and the second spinning solution is adjusted at a ratio of 1: 2, so that the area of the thermal bonding part is about 67%. A heat-sealable fibrous web shown in FIG. 6 made of fibers was prepared.

As shown in FIG. 6, as the area of the thermally bonded portion exceeded 50%, excessive welding occurred at the interface, and it can be seen that this caused a large fluctuation in pores.

<Examples 3 to 5>

Manufactured in the same manner as in Example 1, but by controlling the supply speed of the first spinning solution and the second spinning solution to produce a side-by-side heat-sealable composite fiber having the area of the heat-sealed portion as shown in Table 1 below. A heat-sealable fibrous web was prepared.

<Experimental example>

The following physical properties of the heat-sealable fibrous webs according to Examples 1 to 5 were evaluated and are shown in Table 1 below.

1. Mechanical strength

Mechanical strength was measured by a tensile tester according to ASTM D882-95a for the heat-sealable fiber webs according to Examples 1 to 5, and the area of the specimen was 0.5 cm in width, 6.0 cm in gauge length, and 10 mm/min. of cross-head speed. In addition, with respect to the evaluation results, the measured values of Example 1 were set as 100, and the measured values of the other examples were expressed as relative percentages.

2. Air permeability fluctuation rate

After measuring the air permeability (initial air permeability) with an air permeability meter (MODEL FX-3300, TEXTEST Co.) to check the pore fluctuation rate according to thermal fusion, heat and pressure of 120 ° C were applied twice to the specimen for each example After applying After measuring the air permeability (final air permeability) again under the same pressure conditions, the air permeability fluctuation rate was calculated according to the following formula. It can be evaluated that the larger the air permeability fluctuation rate, the larger the pore fluctuation due to thermal compression.

[ceremony]

Air permeability fluctuation rate (%) = [(initial air permeability (ccs) - final air permeability (ccs))/initial air permeability (ccs))] × 100

Example 1 Example 2 Example 3 Example 4 Example 5 fiber type Side-by-side composite fiber Thermal bonding area in composite fibers (%) 50 67 5 11 30 Mechanical strength (%) 100 105.0 70.9 88.4 96.7 Air permeability fluctuation rate (%) 16.1 48.4 0.6 1.1 3.8

As can be seen from Table 1,

Even in the case of the heat-sealable fibrous web formed of side-by-side type composite fibers, it was confirmed that there was a difference in mechanical strength and air permeability fluctuation rate according to the area of the heat-sealed part in the composite fiber, and compared to Examples 2 and 3, Example It can be seen that the fibrous webs according to 1, 4, and 5 can simultaneously achieve mechanical strength and air permeability fluctuation rate.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments presented herein, and those skilled in the art who understand the spirit of the present invention may add elements within the scope of the same spirit. However, other embodiments can be easily proposed by means of changes, deletions, additions, etc., but these will also fall within the scope of the present invention.

Claims (11)

(1) preparing a first spinning solution in which a support component, which is a first polymer compound, is dissolved, and a second spinning solution in which a thermal bonding component, which is a second polymer compound having a melting point at least 50 ° C. lower than that of the first polymer compound, is dissolved, respectively ;
(2) After transferring the first spinning solution and the second spinning solution through different channels so that the spinning solutions are not blended to the end of the discharge port of one spinning nozzle of the electrospinning device, the first spinning solution is transferred to a certain part of the end surface of the discharge port. accumulating side-by-side heat-sealable composite fibers having a diameter of less than 1 μm by electrospinning so that the second spinning liquid is discharged to the remaining portion; and
(3) preparing a heat-sealable fibrous web by applying heat to the accumulated side-by-side heat-sealable composite fibers. According to claim 1,
The first spinning solution and the second spinning solution contain the same type of solvent. According to claim 1,
The first polymer compound includes at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polybenzyl imidazole (PBI), and high melting point polyethersulfone (PES),
The second polymer compound is a heat-sealable fibrous web manufacturing method comprising at least one of low-melting polyethersulfone and polyvinyl butyral. According to claim 2,
The method of manufacturing a heat-sealable fiber web in which the solvent is a mixture of at least one solvent of dimethylformamide and dimethylacetamide, or a mixture of acetone or alcohol with at least one solvent of dimethylformamide and dimethylacetamide. According to claim 1,
In step (3), heat is applied at a temperature higher than the glass transition temperature and lower than the melting point of the second polymer compound. A side-by-side heat-sealable composite having a diameter of less than 1 μm in which a support part formed of a first polymer compound in a cross section and a heat-sealed part formed of a second polymer compound having a melting point at least 50° C. lower than that of the first polymer compound are adjacently disposed. A heat-sealable fiber web with a three-dimensional network structure in which fibers are accumulated and welded between the surfaces of the composite fibers in contact. According to claim 6,
The heat-sealable fibrous web in which the area of the heat-sealed portion in the cross-section of the heat-sealable composite fiber is 50% or less of the cross-sectional area. According to claim 6,
The area of the thermally bonded portion is 10 to 30% of the cross-sectional area of the heat-sealable fibrous web. According to claim 6,
The heat-sealable fiber web of claim 1 , wherein the first polymer compound includes polyvinylidene fluoride, and the second polymer compound includes polyvinyl butyral. Side-by-side type thermal bonding in which a support part formed of a first polymer compound having a diameter of less than 1 μm and a thermal bonding part formed of a second polymer compound having a melting point at least 50 ° C lower than that of the first polymer compound is disposed adjacent to each other in a cross section. sexual composite fibers. A waterproof and dustproof sound-permeable sheet comprising the heat-sealable fiber web according to any one of claims 6 to 9.

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