WO2013066022A1 - Laminated nanofiber web and method for producing same, and nanofiber composites using same - Google Patents

Abstract

The present invention relates to a laminated nanofiber, a method for producing the same, nanofiber composites using the same and to a method for producing the composites, in which multi-layer nanofiber web is produced by electrospinning polymers having different melting points, an upper layer polymeric substance having a low-melting point is thermally compressed to partially melt a surface of the nanofiber web and thus provide coating effects, thereby maintaining resistance against external scratches and durability against washing while achieving superior air and moisture permeability.

Description

Laminated nanofiber web and manufacturing method thereof, and nanofiber composite using same

The present invention relates to a laminated nanofiber web having a coating effect on its surface for improving the durability of the nanofiber web, a method of manufacturing the same, and a nanofiber composite material using the same, specifically, obtained by electrospinning two or more polymers. The present invention relates to a laminated nanofiber web and a method of manufacturing the same, and a nanofiber composite material having a coating effect applied to a surface by preparing a laminated nanofiber web of two or more layers and partially melting the surface layer of the nanofiber web through a thermocompression bonding process.

Conventional waterproofing is to coat or laminate the rubber or acrylic resin to prevent rain or water from penetrating from the outside to have a fully waterproof function. However, it does not emit sweat, steam, heat, etc. from the inside, so that the problem of unpleasant feelings arises when worn, and the material which appeared to solve this problem is a moisture-permeable waterproof material. Moisture-permeable waterproof material blocks moisture from the outside such as fog, rain and snow, and permeates fine moisture such as sweat, and so on climbing products such as hiking clothes, sleeping bags, hats, gloves, sportswear, military uniforms, tents, etc. It is a widely used fabric that can be encountered frequently in life.

Existing moisture-permeable waterproof materials do not sufficiently dissipate the internal sweat, water vapor, heat, etc. emitted from the human body compared to the waterproof performance to the outside when wearing clothing made of these materials has always been a problem. Therefore, there has been a demand for the development of nano webs that have improved the performance of high breathability, light weight, and soft touch, which are not provided with conventional moisture-permeable waterproof materials.

On the other hand, the electrospinning method is a technique for obtaining nanofibers having a three-dimensional laminated structure simultaneously with spinning by an electric field formed by applying a high voltage to the polymer melt, it is possible to control the size of the pores by controlling the fiber diameter, lamination.

However, the electrospinning nanoweb has a disadvantage in that the mechanical properties are significantly lower than the conventional film-type membranes, and since the nanofibers are not bonded and fixed, mechanical properties such as strength are significantly lower than those of conventional materials. There is a disadvantage that peeling or scratching occurs.

In order to overcome this drawback, the Korean Patent Application Publication No. 10-2011-0095753 proposed by the present applicant provides a blend of electrospun polymers having different melting points or a nanofiber web through cross-electrospinning, and partially melts a low melting polymer material to provide mechanical properties. It is disclosed a method of manufacturing a nanofiber composite by preparing a self-sealing nanofiber web improved by bonding it to a fabric.

However, in the nanofiber web obtained by the blend spinning or cross spinning, the low melting polymer and the high melting polymer nanofiber are distributed evenly throughout the web, so that partial melting may improve the bonding strength between the nanofibers constituting the web. Since it is difficult to uniformly control the pore distribution of the fibrous web, there is a limit in implementing high water pressure, and also the water resistance is drastically lowered due to the contamination problem caused by the penetration of detergent during washing.

In order to overcome these disadvantages, attempts have been made to overcome scratch resistance and durability after washing through hydrophilic PU coating on nano webs, but in this case, the advantages of nanofiber webs, such as breathability, light weight and softness There is a problem that is accompanied by a decrease in performance.

The present invention is to solve the above problems, an object of the present invention is to produce a two-layer or multi-layer nanofiber web obtained by electrospinning two or more kinds of polymers having different melting points, the surface layer is thermally compressed It is to provide a nanofiber web and a method of manufacturing the same by partially melting through imparting a surface coating effect.

Another object of the present invention is to partially melt the surface of the nanofiber web through heat compression processing to impart a surface coating effect, thereby preventing surface scratches caused by external forces and water resistance deterioration due to infiltration of detergent during washing. It is to provide a nanofiber web with a function of.

Still another object of the present invention is to provide a composite sheet composited with a base fabric provided with a waterproof function to the nanofiber web prepared above, or a breathable waterproof fiber structure having maximum breathability, moisture permeability, and softness.

Still another object of the present invention is to provide a composite sheet having functionality such as washing durability, scratch durability, etc., in the composite sheet provided with water pressure resistance, moisture permeability, and breathability.

According to an aspect of the present invention for achieving the above object, a nanofiber layer of a high melting point polymer; And a nanofibrous layer of a low melting point polymer formed on the nanofibrous layer of the high melting point polymer, wherein the nanofibers of the low melting point polymer are partially melted to provide a laminated nanofiber web.

According to another aspect of the invention, dissolving a high melting point polymer material in a solvent to prepare a first spinning solution; Preparing a second spinning solution by dissolving a low melting polymer in a solvent; Sequentially spinning the first and second spinning solutions to form a nanofibrous layer of a low melting polymer on top of the nanofibrous layer of a high melting polymer; And it provides a method for producing a laminated nanofiber web comprising the step of producing a laminated nanofiber web by thermocompression so that the nanofibrous layer of the low melting point polymer is partially melted.

According to another aspect of the invention, the base material; Nanofibrous layers of high melting point polymers formed on one or both surfaces of the base material; And a nanofibrous layer of a low melting point polymer formed on the nanofibrous layer of the high melting point polymer, wherein the nanofibers of the low melting point polymer are partially melted to provide a laminated nanofiber composite.

The low-melting and high-melting polymers are low-polymer polyurethane (polyurethane), high-polymer polyurethane, PS (polystylene), PVA (polyvinylalchol), PMMA (polymethyl methacrylate), polylactic acid (PLA: polylactic acid), PEO (polyethyleneoxide) , PVAc (polyvinylacetate), PAA (polyacrylic acid), polycaprolactone (PCL: polycaprolactone), PAN (polyacrylonitrile), PVP (polyvinylpyrrolidone), PVC (polyvinylchloride), nylon (Nylon), PC (polycarbonate), PEI (polyetherimide) , PVdF (polyvinylidene fluoride), PES (polyesthersulphone) is characterized in that the manufacturing by selecting a polymer having a different melting point.

The solvent is DMAc (dimethyl acetamide), DMF (N, N-dimethylformamide), NMP (N-methyl-2-pyrrolidinone), DMSO (dimethyl sulfoxide), THF (tetra-hydrofuran), EC (ethylene carbonate), DEC (DEC) diethyl carbonate, dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), propylene carbonate (PC), water, acetic acid, formic acid, chloroform, chloroform, dichloromethane and acetone It is characterized in that any one or more selected from the group consisting of.

The polymer material is characterized in that mixed in 5 to 22.5% by weight in each spinning solution for electrospinning.

The solvent used in the spinning solution is characterized in that the two-component solvent mixed with a high boiling point (BP: boiling point) and low.

The low melting point polymer has a melting point of 50 to 170 ° C, and the high melting point polymer has a melting point of 80 to 250 ° C.

The base material is characterized in that any one or more selected from woven paper, nonwoven fabric, foam, paper, mesh. The nanofiber web is composed of multiple layers of two or more layers.

The base material may be formed in a two-layer structure with the nanofiber web, or may be formed in a three-layer structure in which the nanofiber web is interposed between the base material.

As described above, in the present invention, the low-melting-point nanofibers are partially melted in the thermocompression process of the nanofiber web obtained by electrospinning polymer materials having different melting points, thereby improving the fastness of external scratches, washing durability, and the like. It can be usefully applied in the manufacture of lightweight materials having excellent moisture permeability, water resistance and thermal insulation can be adjusted in various ways.

In the present invention, it is possible to produce a composite sheet excellent in moisture-permeable waterproof function by combining the nanofiber web and the base material to give a surface coating effect can be utilized as a fiber material in various fields.

1 is a schematic diagram of air electrospinning for schematically illustrating a process of manufacturing a nanofiber web according to the present invention;

2 is a manufacturing process diagram for schematically illustrating a process of manufacturing a nanofiber composite according to the present invention;

3 to 5 are scanning electron micrographs of the nanofiber web prepared by Example 1 of the present invention,

6 is a scanning electron micrograph of a nanofiber web prepared by Example 3 of the present invention,

7 is a scanning electron micrograph of a nanofiber web prepared by Example 4 of the present invention,

8 is a scanning electron micrograph of the nanofiber web prepared by Example 5 of the present invention.

Hereinafter, according to the present invention with reference to the accompanying drawings, the melting point of the low melting point and the high melting point polymer using a different solvent to prepare a first spinning solution and a second spinning solution and using different spinning nozzles After electrospinning two or more spinning solutions to form two or more laminated nanofiber webs, the obtained nanofiber web is subjected to a thermocompression process (eg, calendaring) to partially melt the nanofibers of a low melting polymer component. It is possible to produce a laminated nanofiber to give a surface coating effect.

According to the present invention, when the nanofiber web formed by electrospinning using low melting point and high melting point polymers is subjected to heat treatment such as calendering, the nanofibers of low melting point polymer component are partially melted to give nanofibers which give a surface coating effect. It can be produced a durable nanofiber without a process for a separate surface coating.

Nanofiber manufacturing method in the present invention is electrospinning, electro-spray, air electro-spinning, centrifugal electro-spinning, flash electrospinning (flash) Various methods of spinning such as electro-spinning can be appropriately adopted and used. Preferably, the production of a laminated nanofiber web imparting a coating effect to the nanofibers according to the present invention is made by an air electrospinning (AES) method.

The nanofiber web produced by the air electrospinning (AES) method has a low melting point of 50-170 ° C. and a nanofiber phase by electrospinning a high melting point polymer material having a melting point of 80-250 ° C. It comprises a nanofiber phase by the electrospinning of the polymer material. Here, the high melting point polymer material increases the mechanical properties of the nanofiber web, and the low melting point polymer material plays a role of enhancing scratching and washing durability from the outside of the nanofiber web by partial melting.

As the polymer material used in the present invention, electrospinning is possible, and examples thereof include hydrophilic polymers and hydrophobic polymers, and these polymers may be used alone or in combination of two or more thereof.

The polymer material usable in the present invention is not particularly limited as long as it is a polymer that can be dissolved in an organic solvent for electrospinning and can form nanofibers by electrospinning. Examples include polyvinylidene fluoride (PVdF), poly (vinylidene fluoride-co-hexafluoropropylene), perfuluropolymers, polyvinylchloride, polyvinylidene chloride or copolymers thereof, polyethylene glycol dialkyl Polyethylene glycol derivatives including ethers and polyethylene glycol dialkyl esters, poly (oxymethylene-oligo-oxyethylene), polyoxides including polyethylene oxide and polypropylene oxide, polyvinylacetate, poly (vinylpyrrolidone-vinyl Acetates), polystyrene and polystyrene acrylonitrile copolymers, polyacrylonitrile (PAN), polyacrylonitrile copolymers including polyacrylonitrile methyl methacrylate copolymer, polymethyl methacrylate, polymethyl methacrylate And latex copolymers or mixtures thereof.

Also, polyamide, polyimide, polyamideimide, poly (meth-phenylene isophthalamide), polysulfone, polyetherketone, polyetherimide, polyethylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate and the like Polyphosphazenes such as aromatic polyesters, polytetrafluoroethylene, polydiphenoxyphosphazenes, poly {bis [2- (2-methoxyethoxy) phosphazene]}, polyurethanes and polyetherurethanes Polyurethane copolymers, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, and the like.

Particularly preferred among the polymer materials for the production of the nanofiber web of the present invention is polyvinylidene fluoride (PVdF), thermoplastic polyurethane (TPU: Thermoplastic Polyurethane), PAN, polyester sulfone (PES: Polyester Sulfone), polystyrene (PS) May be used alone, or polyvinylidene fluoride (PVdF) and polyacrylonitrile (PAN) may be mixed, or PVdF and PES, PVdF and thermoplastic polyurethane (TPU) may be mixed, but are limited to the above materials. There is no particular limitation as long as it is a polymer material capable of forming nanofibers by electrospinning.

The solvent is DMAc (N, N-Dimethyl acetoamide), DMF (N, N-Dimethylformamide), NMP (N-methyl-2-pyrrolidinone), DMSO (dimethyl sulfoxide), THF (tetra-hydrofuran), (EC (ethylene) carbonate), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), propylene carbonate (PC), water, acetic acid, formic acid, chloroform, dichloromethane ( dichloromethane) and acetone (acetone) is characterized in that any one or more selected from the group consisting of.

The base material is any one or more selected from the group consisting of woven paper, nonwoven fabric, foam, paper, mesh, and the like.

In addition, in the production of the nanofibers of the present invention, in order to form a fibrous structure, the polymer material is preferably prepared in an amount of 5 to 22.5 wt% to control the morphology of the fibers.

Here, if the content of the polymer material is less than 5% by weight, it is difficult to form a fibrous shape, and even if particles are formed or spun, rather than spinning due to spraying, spraying is not performed. ) Is formed a lot, the volatilization of the solvent is not well made during the calendar process of the web melts the pore (pore) occurs. In addition, when the content of the polymer material exceeds 22.5% by weight, the viscosity rises, so that solidification occurs at the surface of the solution, which makes it difficult to spin for a long time.

In order to prepare the spinning solution, the solvent mixed with the high molecular material may use a monocomponent solvent such as dimethylformamide (DMF), but in the case of using the bicomponent solvent, boiling point (BP) It is preferable to use a solvent mixed with a high and a low point).

The two-component mixed solvent according to the present invention is preferably used by mixing a high boiling point solvent and a low boiling point solvent in a weight ratio of 7: 3 to 9: 1. When the high boiling point solvent is less than 7, there is a problem that the polymer is not completely dissolved, and when it exceeds 9, the low boiling point solvent is too small to volatilize the solvent from the spun fibers so that the formation of a web is smooth. The problem does not occur.

If only a solvent having a high boiling point is used, spinning is not performed and spray is formed, even though particles are formed instead of fibers, or even if spinning occurs, a lot of beads are formed. Due to poor volatilization of the solvent, partial melting occurs during the lamination process of the web, causing pore clogging.

In addition, when only a low boiling point solvent is used, volatilization of the solvent occurs very quickly, and thus, many fine fibers are generated on the needle of the spinning nozzle, which causes the spinning trouble.

In the present invention, when the polymer material is PVdF and TPU, respectively, the two-component mixed solvent is, for example, DMAc (N, N-dimethylacetoamide: BP-165 ° C.) as a high boiling point solvent and acetone (acetone: BP-56) as a low boiling point solvent. ℃) may be used by mixing in a weight ratio of 9: 1. In this case, the mixing ratio between the two-component mixed solvent and the entire polymeric material is preferably set to about 8: 2 by weight.

When the above-mentioned polymer is used alone or mixed, the spinning solution dissolved in the solvent is air electrospun using a multi-hole spinning pack, and then a nanofiber web formed in a multi-layer is obtained and a thermal compression process, for example, calendaring, is performed. A nanofiber web is obtained in which the low melting polymer on the surface is uniformly melted.

The method of forming the nanofiber web according to the present invention is realized using the air electrospinning apparatus shown in FIG.

In the air electrospinning method of the present invention, nanofibers are radiated to the collector 6 by applying a high voltage electrostatic force of 90 to 120 KV between the spinneret nozzle 4 and the collector 6 on which the polymer solution having a sufficient viscosity is spun. The fiber web 7 is formed, and in this case, by spraying air at each spinning nozzle 4, the spun fiber is caught in the collector 6 and blown off.

Referring to FIG. 1, the air electrospinning apparatus of the present invention includes a spinning solution tank 1 in which a spinning solution in which a polymer material is mixed with a solvent is stored, and a plurality of spinning nozzles 41 to 44 connected to a high voltage generator (not shown). ) Includes a multi-hole spin pack 40 arranged in multiple columns / multiple rows.

The spinning pack 40 is disposed above the grounded collector 6 of the conveyor type moving at a constant speed, a plurality of spinning nozzles are arranged at intervals along the traveling direction of the collector 6, A plurality of spinning nozzles are arranged at intervals along a direction orthogonal to the traveling direction of the collector 6 (that is, the width direction of the collector). In FIG. 1, four spinning nozzles are arranged at intervals along the traveling direction of the collector 6 for convenience of description.

The radiation nozzles arranged along the traveling direction of the collector 6 may be arranged, for example, 30-60 or more, as required, and in the case of using a plurality of radiation nozzles, the collector 6 The productivity can be increased by increasing the rotational speed of.

The spinning solution tank 1 may have a built-in agitator 2 using a mixing motor 2a as a driving source to prevent phase separation until the low melting polymer material and the high melting polymer material are mixed with a solvent to form spinning. It is connected to the spinning nozzles 41-44 of each row through the metering pump and the conveying pipe 3 which are not shown from the spinning solution tank.

On the other hand, spinning can be performed by PVdF alone or by mixing PVdF and TPU. At this time, the first nanofiber web 7a is composed of fibers 51 in which the spinning solution is spun from the first spinning nozzle 41, and the second nanofiber web 7b is spinning solution from the second spinning nozzle 42. The first nanofiber web 7a is composed of fibers 52 spun onto the top, and the third nanofiber web 7c has a spinning solution from the third spinning nozzle 43 with the second nanofiber web 7b. It is made of a fiber 53 spun to the top of. Finally, the spinning solution from the fourth spinning nozzle 44 is composed of the fibers 54 spun onto the third nanofiber web 7c to finally obtain a multi-layered nanofiber web 7 of four layers. have.

The first to third nanofiber webs 7a to 7c may be formed by stacked spinning of nanofibers by PVdF alone from three rows of spinning nozzles 41 to 43, and formed on top of the web formed from three rows of spinning nozzles. A nanofiber web composed of two layers may be manufactured by stacking nanofibers in which PVdF and TPU are mixed from the fourth spinning nozzle 44.

The polymer spinning solution discharged sequentially from four rows of spinning nozzles 41 to 44 passes through the spinning nozzles 41 to 44 charged by the high voltage generator, respectively, and is discharged to the ultrafine fibers 5 to move at a constant speed. Nanofibers are sequentially accumulated on the grounded collector 6 of the form to form a multilayer nanofiber web 7.

In the case of using a plurality of multi-hole spinning packs 40 for mass production, the nanofiber webs obtained due to mutual interference, which are not blown while the fibers are blown out, become too bulky and cause troubles in the spinning. ) Acts as a cause.

In consideration of this, in the present invention, the air 4a is sprayed from a plurality of air injection nozzles (not shown) for each of the radiation nozzles 41 to 44 of each row using the multi-hole spinning pack 40. The multilayer nanofiber web 7 is formed by an air electrospinning method.

Accordingly, in the air electrospinning apparatus of the present invention, when the spinning solution is radiated for each spinning nozzle of each row, the air injection may be simultaneously performed from the multi-hole spinning pack nozzle.

That is, in the present invention, when the electrospinning is carried out by air electrospinning, the air is sprayed from the outer circumference of the spinning nozzle to play a dominant role in collecting and integrating the air, which is composed of a polymer having a high volatility, in the air. It is possible to produce high nanofiber webs and to minimize the radiation troubles that can occur as the fibers fly around.

The spin pack nozzle of the multi-hole spinning pack 40 used in the present invention is set in the range of 0.1 to 0.6 MPa when the air pressure of the air jet is, for example, 245 mm / 61 holes. In this case, if the air pressure is less than 0.1MPa, it does not contribute to the collection and accumulation. If the air pressure exceeds 0.6MPa, the cone of the spinning nozzle is hardened to block the needle, causing radiation trouble.

On the other hand, when spinning by air-electrospinning (AES), the temperature and humidity inside the spinning chamber have a great effect on the volatilization of the solvent from the spinning fibers, and if the proper conditions are not established, Radish is determined, and also the diameter of the fiber and the presence / absence of beads are determined.

If the temperature and humidity conditions inside the spinning chamber are different, one of the spinning nozzles 41 of the first row and the spinning nozzles 42 of the second row is impossible to spin, or the web produced by the subsequent process may be formed from the web of the previous process. Adhesion may be degraded and separated.

The air electrospinning apparatus shown in FIG. 1 illustrates the formation of four layers of nanofiber webs 7 by four spinning nozzles 41-44. However, the present invention provides a plurality of rows and columns. As the high speed spinning and the high speed rotation are performed using the multi-hole spinning pack 40 having the spinning nozzles arranged, a nanofiber web having a multilayer structure made of ultra-thin films is obtained for each layer.

In this way, the multi-layer nanofiber web 7 is formed by air electrospinning, and in the thermocompression calendering process of the multi-layer nanofiber web, a heat compression roller (not shown) is used, in which case the calendering temperature is too low. If the web is too bulky to have rigidity, and if the temperature is too high, the web will melt during processing and the pores will be blocked.

Therefore, the calendering temperature is a temperature at which the low melting polymer used may be partially melted, for example, about 50 to 170 ° C. It has a big influence on the performance of air permeability, moisture permeability, and water resistance according to the calendering temperature, and it has a big influence on the scratch resistance and the durability of washing according to the degree of partial melting of low melting point polymer.

Water resistance, air permeability, moisture permeability, etc. were evaluated as physical properties of the laminated nanofiber web according to the present invention, and the results are shown in Table 1.

The water resistance was measured using a low water pressure method according to ASTM D 751, and the air permeability was evaluated by ASTM D 737: 2004.

Preparation of the nanofiber composite using the laminated nanofiber web of the present invention can be prepared using a conventional fabrication method, preferably hot melt bonding, solvent bonding, thermal bonding, ultrasonic bonding, laser irradiation, high frequency treatment, Water jet and the like.

The physical properties of the nanofiber composite according to the present invention were evaluated for water resistance, water resistance after washing, air permeability, moisture permeability, and the results are shown in Table 2.

Hereinafter, with reference to Figure 2, it will be described in more detail the manufacturing process of the laminated nanofiber web and composite material given a coating effect according to the present invention.

Figure 2 is a manufacturing process of the moisture-permeable waterproof fabric according to an embodiment of the present invention.

Referring to Figure 2, as described above to dissolve the polymer material in a solvent to prepare a spinning solution (S1). The spinning solution is put into the spinning solution tank 1 of FIG. 1 for air electrospinning to perform air electrospinning (S2), and the multilayer nanofiber web 7 is formed (S3). The multilayer nanofiber web 7 thus formed is subjected to primary calendering as necessary (S4) and then dried (S5). Primary calendering is to remove the solvent and water and compress the web. When drying is complete, secondary calendering (S6) is performed to partially melt the low-melting polymer material to prepare a laminated nanofiber web given a coating effect. The laminated nanofiber web prepared is subjected to lamination and maturing through the fabric and laminating process (S7). Water-repellent finishing (S8) is carried out to the finished fabric to prepare a waterproof moisture-repellent fabric.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are intended to illustrate the present invention in more detail, and the scope of the present invention is not limited by the following examples, and the following examples are appropriately changed by those skilled in the art within the scope of the present invention. Can be.

<Example 1>

High melting point polymer: PVdF 17wt%-Acetone: DMAc = 3: 7

Low melting point polymer: TPU 12wt%-DMAc

In order to prepare nanofiber webs by air electrospinning (AES), polyvinylidene fluoride (PVdF: Polyvinylidenefluoride), a high melting point polymer, was added to a mixed solvent of Acetone and DMAc (30:70 vol%) in 17wt%. A spinning solution was prepared by dissolving to%, and a spinning solution was prepared by dissolving a low melting polymer TPU in DMAc to 12 wt%.

Two spinning solutions were put in a tank, respectively, and the polymer solution was discharged at 17.5 ul / min / hole. At this time, while maintaining the temperature of the spinning section 30 ℃, humidity 50% using a high voltage generator to give a 100KV voltage to the spinning nozzle pack and at the same time give a 0.2MPa air pressure per spinning pack nozzle to produce a nanofiber web It was.

PVdF nanofiber web, a high melting point polymer material, was prepared with a basis weight of 4gsm, and TPU nanofiber web, a low melting point polymer material, was prepared with a basis weight of 2gsm on the top thereof to prepare a laminated nanofiber web.

In order to increase the strength of the nanofiber web thus prepared, solvent and water remaining on the surface of the nanofiber web by passing a primary line drying section in which 30 ° C air is circulated at a speed of 30 m / sec at 3 m / min Was adjusted. The nanofiber web thus adjusted was calendered when the calender rolls were heated to 50, 70 and 100 ° C, respectively.

In order to measure the performance of the obtained nanofiber web, water resistance was measured by the low water pressure method according to ASTM D 751, and air permeability was measured by ASTM D 737: 2004.

In order to determine the degree of partial melting of the low-melting polymer TPU, a scanning electron microscope was used.

3 to 5 are scanning electron micrographs of nanofiber webs melted at different temperatures. From FIG. 3, when the temperature of the calender roll is 50 ° C., the nanofibers of the low melting point polymer component are hardly melted. In FIG. 4, where the temperature of the calender roll is 70 ° C., the nanofibers of the low melting point polymer component are partially melted. Shows the starting state.

In addition, FIG. 5 shows a state in which the nanofiber of the low melting polymer component is sufficiently melted when the temperature of the calender roll is 100 ° C. However, even in this case, it can be confirmed that the three-dimensional pore structure is maintained as it is.

<Example 2>

Laminated nanofibers were prepared in the same manner as in Example 1, except that PVdF nanofiber web, a high melting point polymer material, was prepared with a basis weight of 5 gsm, and TPU nanofiber web, a low melting point polymer material, was used with a basis weight of 1 gsm. The web was prepared.

In order to increase the strength of the nanofiber web thus prepared, solvent and water remaining on the surface of the nanofiber web by passing a primary line drying section in which 30 ° C air is circulated at a speed of 30 m / sec at 3 m / min Was adjusted. The nanofiber web thus adjusted was calendered when the calender rolls were heated to 50, 70 and 100 ° C, respectively.

In order to measure the performance of the obtained nanofiber web, water resistance was measured by the low water pressure method according to ASTM D 751, and air permeability was measured by ASTM D 737: 2004.

<Example 3>

High melting point polymer: PVdF 17wt%-Acetone: DMAc = 3: 7

Low melting point polymer: TPU / PVdF 13wt% (70:30 vol%)-DMAc

In order to prepare nanofiber webs by air electrospinning (AES), polyvinylidene fluoride (PVdF: Polyvinylidenefluoride), a high melting point polymer, was added to a mixed solvent of Acetone and DMAc (30:70 vol%) in 17wt%. A spinning solution was prepared by dissolving to%, and a low melting point polymer material, TPU and PVdF, was blended, dissolved in DMAc, and dissolved to 13 wt% to prepare a spinning solution.

Two spinning solutions were put in a tank, respectively, and the polymer solution was discharged at 17.5 ul / min / hole. At this time, while maintaining the temperature of the spinning section 30 ℃, humidity 50% using a high voltage generator to give a 100KV voltage to the spinning nozzle pack and at the same time give a 0.2MPa air pressure per spinning pack nozzle to produce a nanofiber web It was.

PVdF nanofiber web, a high melting point polymer material, was prepared with a basis weight of 4gsm, and TPU nanofiber web, a low melting point polymer material, was prepared with a basis weight of 2gsm on the top thereof to prepare a laminated nanofiber web.

In order to increase the strength of the nanofiber web thus prepared, solvent and water remaining on the surface of the nanofiber web by passing a primary line drying section in which 30 ° C air is circulated at a speed of 30 m / sec at 3 m / min Was adjusted. The nanofiber web thus adjusted was calendered when the calender rolls were heated to 100, 130 and 150 ° C, respectively.

In order to measure the performance of the obtained nanofiber web, water resistance was measured by the low water pressure method according to ASTM D 751, and air permeability was measured by ASTM D 737: 2004.

In order to determine the degree of partial melting of the low melting polymer TPU, it was photographed using a scanning electron microscope. In FIG. 6, it can be seen that the nanofibers are sufficiently partially melted at a temperature of the calender roll at 150 ° C. to maintain the pore structure.

<Example 4>

High melting point polymer: PVdF 17wt%-Acetone: DMAc = 3: 7

Low melting point polymer: TPU / PVdF 13wt% (50:50 vol%)-DMAc

A spinning solution was prepared such that the mixing ratio of the low melting polymer material used in Example 3 was 13 wt% (50:50 vol%) of TPU / PVdF.

Two spinning solutions were put in a tank, respectively, and the polymer solution was discharged at 17.5 ul / min / hole. At this time, while maintaining the temperature of the spinning section 30 ℃, humidity 50% using a high voltage generator to give a 100KV voltage to the spinning nozzle pack and at the same time give a 0.2MPa air pressure per spinning pack nozzle to produce a nanofiber web It was.

PVdF nanofiber web, a high melting point polymer material, was prepared with a basis weight of 4 gsm, and a TPU nanofiber web, a low melting point polymer material, was prepared with a basis weight of 2 gsm, to prepare a laminated nanofiber web.

In order to increase the strength of the nanofiber web thus prepared, the solvent and water remaining on the surface of the nanofiber web by passing the first-line drying section where air at 30 ° C. circulates at a speed of 30 m / sec at 3 m / min Was adjusted. The nanofiber web thus adjusted was calendered when the calender rolls were heated to 100, 130 and 150 ° C, respectively.

In order to measure the performance of the obtained nanofiber web, water resistance was measured by the low water pressure method according to ASTM D 751, and air permeability was measured by ASTM D 737: 2004.

In order to determine the degree of partial melting of the low melting polymer TPU, it was photographed using a scanning electron microscope. In FIG. 7, it can be seen that the nanofibers are sufficiently partially melted at a temperature of the calender roll at 150 ° C. to maintain the pore structure.

Comparative Example 1

Low melting point polymer with softening temperature of 80 ~ 100 ℃, low polymerization polyurethane (moisture curing type resin) and high melting point polymer with softening temperature of 140 ℃ or higher, high polymerization polyurethane is mixed in a ratio of 50:50 (wt%) and THF ( A spinning solution was prepared by dissolving 15% by weight in a mixed solvent of tetrahydrofuran) and DMAc (N, Ndimethylaceticamide) at a ratio of 50:50 (vol%).

Using the same nozzle using the same nozzle, the applied voltage is 25kV, the distance between the radiation nozzle and the current collector 20cm, discharge amount 0.05cc / g-hole per minute at 30 ℃, relative humidity 60% Electrospinning (blend spinning) was carried out by the method disclosed in the above to obtain a nanofiber web prepared with a basis weight of 6 gsm.

The nanofiber web prepared as described above was thermally compressed through the same process as in Example 1 except that calendering was performed when the calender roll was heated to 100 ° C., and then the water resistance, air permeability, The moisture permeability and the like were evaluated, and the results are shown in Table 1 together.

Comparative Example 2

The low-polymerization polyurethane and the high-polymerization polyurethane used in Comparative Example 1 were dissolved in a mixed solvent of THF and DMAc (50:50 vol%) to 20 wt% and 15 wt%, respectively, to prepare respective spinning solutions.

Two spinning solutions were electrospun (cross spinning) by the method disclosed in the Republic of Korea Patent Publication No. 10-2011-0095753 through each injection nozzle to obtain a nanofiber web made of a basis weight of 6gsm. At this time, the voltage and the radiation amount used were the same as in Example 1.

The nanofiber web prepared as described above was thermally compressed through the same process as in Example 1 except that calendering was performed when the calender roll was heated to 100 ° C., and then the water resistance, air permeability, The moisture permeability and the like were evaluated, and the results are shown in Table 1 together.

Table 1 division Basis weight (g / m ² ) Calendering Temperature (℃) Air Permeability (CFM) Water resistance (mmH ₂ O) High melting point material (PVdF) Low melting point material (TPU or TPU / PVdF) Example 1 4 2 70 1.6 6000 4 2 100 1.3 8000 Example 2 5 One 50 1.8 4000 5 One 70 1.6 6000 5 One 100 1.4 7000 Example 3 4 2 100 1.5 6000 4 2 130 1.3 8000 4 2 150 1.2 8000 Example 4 4 2 100 1.7 6000 4 2 130 1.6 7000 4 2 150 1.3 8000 Comparative Example 1 6 100 1.1 5000 Comparative Example 2 6 100 1.2 4500

The water resistance of ash, water resistance after washing, air permeability, moisture permeability, etc. were measured and shown in Table 2.

8 is a scanning electron micrograph showing a cross section of a nanofiber composite.

Comparative Example 3

A nanofiber web and a base material cross-electrospun by Comparative Example 2 were passed through a calender roll heated at 100 ° C. with a nanofiber web and a base material to melt the nanofibers of a low melting polymer (low polymerization degree polyurethane) component. The nanofiber composites were self-fused between the base fabric and the base fabric. In order to determine the properties of the obtained nanofiber composite material, the water resistance, water resistance after washing, air permeability, moisture permeability, etc. of the nanofiber composite were measured in the same manner as in Example 5, and the results are shown in Table 2 together.

TABLE 2 division Calendering Temperature (℃) Air Permeability (CFM) Water resistance (mmH ₂ O) Water resistance after washing three times (mmH ₂ O) Example 1 70 1.2 6500 1500 100 1.2 8000 4500 Example 2 70 1.2 6000 1700 100 1.2 7500 3800 Example 3 100 1.2 6000 2500 130 1.1 8000 4500 150 1.0 8000 5500 Example 4 100 1.2 6000 2000 130 1.1 7000 4300 150 1.0 8000 5200 Comparative Example 3 100 0.8 4500 900

From the results in Table 2, it can be seen that the water resistance after washing is sharply lowered in the case of the comparative example compared to the embodiment of the present invention. The reason for this is that in the case of the present invention, the surface layer is partially melted with a low melting polymer and thus the actual water resistance. This is because it protects the nanofiber web of high melting point polymer material that realizes its characteristics from the outside, so that it is less influenced by external scratches during washing, and the molten portion prevents the detergent from penetrating the detergent problem. .

However, in the case of conventional blend spinning or cross spinning, the surface is more affected by scratches than the present invention, and there is a limit in preventing the penetration of detergent, so that high water pressure cannot be realized, and the water resistance after washing is severely deteriorated. Does not have laundry durability.

In the above, the present invention has been illustrated and described with reference to specific preferred embodiments, but the present invention is not limited to the above-described embodiments, and the present invention is not limited to the spirit of the present invention. Various changes and modifications will be possible by those who have the same.

The present invention improves the fastness due to external factors in the nanofiber web and at the same time can adjust the pore structure to produce the desired material such as waterproof, moisture permeability, air permeability, heat insulation and light weight, filter material, biomedical, moisture absorption It can be applied to various types of clothing such as fabrics, outdoor clothing, military uniforms, NBC protective clothing, extreme cold protection clothing, and functional fabrics.

Claims (15)

Nanofibrous layer of a high melting point polymer; And It comprises a nanofibrous layer of a low melting polymer formed on the nanofibrous layer of the high melting point polymer, Laminated nanofiber web, characterized in that the low-melting polymer nanofibrous layer is formed by partially melting. According to claim 1, wherein the low-melting polymer is a low polymer polyurethane (polyurethane), polystyrene (polystylene), polyvinylalchol (PVA), polymethyl methacrylate (PMMA), polylactic acid (PLA: polylactic acid), PEO (polyethyleneoxide), VAc (polyvinylacetate), polyacrylic acid (PAA), polycaprolactone (PCL), polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), polyvinyl pyrrolidone (PVP), polyacrylonitrile (PAN), or polycarbonate (PC) Laminated nanofiber web, characterized in that at least one. The method of claim 1, wherein the high melting point polymer is a high polymer polyurethane, polyacrylonitrile (PAN), polyetherimide (PEI), polyesthersulphone (PES), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), PC (Polycarbonate), Nylon (Nylon) of the laminated nanofiber web, characterized in that any one or more selected. The laminated nanofiber web of claim 1, wherein the low melting point polymer has a melting point of 50 to 170 ° C., and the high melting point polymer has a melting point of 80 to 250 ° C. 6. Dissolving a high melting point polymeric material in a solvent to prepare a first spinning solution; Preparing a second spinning solution by dissolving a low melting polymer in a solvent; Sequentially electrospinning the first and second spinning solutions to form a nanofibrous layer of a low melting polymer on top of the nanofibrous layer of a high melting polymer; And Method of producing a laminated nanofiber web comprising the step of obtaining a laminated nanofiber web by thermocompression so that the nanofibrous layer of the low melting polymer partially melted. The method of claim 5, wherein the low-melting polymer is a low-polymer polyurethane (polyurethane), polystyrene (polystylene), polyvinylalchol (PVA), polymethyl methacrylate (PMMA), polylactic acid (PLA: polylactic acid), PEO (polyethyleneoxide), PVAc ( at least one selected from polyvinylacetate (PAA), polyacrylic acid (PAA), polycaprolactone (PCL), polyvinylidenefluoride (PVDF), polyvinyl chloride (PVC), polyvinyl pyrrolidone (PVP), polyacrylonitrile (PAN), and polycarbonate (PC) Method for producing a laminated nanofiber web, characterized in that. The method of claim 5, wherein the high melting point polymer is a high-polymer polyurethane, polyacrylonitrile (PAN), polyetherimide (PEI), polyesthersulphone (PES), polymethyl methacrylate (PMMA), poly vinylidenefluoride (PVDF), polyvinylchloride (PVC), PC ( polycarbonate), nylon (Nylon) any one or more selected method for producing a laminated nanofiber web. The method of claim 5, wherein the solvent is dimethyl acetamide (DMA), N, N-dimethylformamide (DMF), N-methyl-2-pyrrolidinone (NMP), dimethyl sulfoxide (DMSO), tetra-hydrofuran (THF), DMAc (DMAc). di-methylacetamide (EC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), propylene carbonate (PC), water, acetic acid, formic acid, Chloroform (Chloroform), dichloromethane (dichloromethane) and a method for producing a laminated nanofiber web, characterized in that any one or more selected from the group consisting of acetone. The method of claim 5, wherein the thermocompression is calendering. The method of claim 5, wherein the low melting point polymer has a melting point of 50 to 170 ° C., and the high melting point polymer has a melting point of 80 to 250 ° C. 7. Base material; Nanofibrous layers of high melting point polymers formed on one or both surfaces of the base material; And It comprises a nanofibrous layer of a low melting polymer formed on the nanofibrous layer of the high melting point polymer, The nanofibrous layer of the low melting point polymer is laminated nanofiber composite, characterized in that formed by melting partially. 12. The laminated nanofiber composite according to claim 11, wherein the low melting point polymer has a melting point of 50 to 170 ° C and the high melting point polymer has a melting point of 80 to 250 ° C. 12. The laminated nanofiber composite according to claim 11, wherein the base material is at least one selected from woven paper, nonwoven fabric, foam, paper, and mesh. The method of claim 5, wherein the polymer material is mixed at 5 to 22.5 wt% based on the respective spinning solutions. The method of claim 8, wherein the solvent is a mixture of different boiling points.

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