KR101721986B1 - Nano membrane and method of manufacturing the same - Google Patents

Abstract

The present invention relates to a method of manufacturing a nanomembrane, and more particularly, to a method of manufacturing a nanomembrane using bottom-up electrospinning, The present invention relates to a method of manufacturing a nanomembrane in which the basis weight of nanofibers is different from that of a nanofiber in a CD direction. The present invention relates to a nanomembrane having different basis weights and a method for producing the same.

Description

NANO MEMBRANE AND METHOD FOR MANUFACTURING THE SAME

The present invention relates to a method of manufacturing a nanomembrane having different basis weights in a normal direction, and more particularly, to a method of manufacturing a nanomembrane different in basis weight in the CD direction (Cross Direction) and a nanomembrane manufactured thereby.

Generally, a nanofiber refers to a microfiber having a diameter of only a few tens to a few hundred nanometers, and is produced by an electric field. That is, nanofibers generate electrical repulsive force inside the polymer material by applying a high voltage electric field to the polymer material, which is the raw material, and the nanofibers are manufactured and produced by breaking the molecules into a nano-sized yarn shape.

At this time, as the electric field becomes stronger, the polymer material as the raw material is finely torn, so that a nanofiber having a thinning of 10 to 1000 nm can be obtained.

In the conventional technology for spinning nanofibers, since it is limited to a small-scale working line focused on a laboratory, there is a demand for a technique of spinning nanofibers by dividing a spinning zone and using a unit concept.

On the other hand, in the conventional electrospinning apparatus, a spinning solution is electrospun on one surface of a substrate supplied from the outside, and a nanomembrane is laminated to produce nanofibers. That is, the conventional electrospinning device comprises a bottom-up or top-down electrospinning device, and the spinning solution is electrospun on only the bottom surface or the top surface of the substrate supplied into the electrospinning device to form a nanomembrane by laminating the nanomembrane.

As described above, since the electrospinning device comprises the bottom-up electrospinning device or the top-down electrospinning device, the spinning solution is electrospun to the bottom surface or the top surface of the substrate supplied from the outside and transported in a predetermined direction, .

As shown in FIG. 1, the top-down electrospinning device of the bottom-up or top-down electrospinning device includes a spinning solution main tank 120 filled with a polymer spinning solution and a polymer spinning solution filled in the spinning solution main tank 120 A nozzle block 111 for discharging the polymer solution in the spinning liquid main tank and having a plurality of nozzles 111a arranged in a pin shape and a nozzle block 111a And a voltage generator 114 for generating a high voltage in the collector 113. The collector 113 is disposed at a predetermined distance from the nozzle 111a in order to collect the polymer spinning solution injected from the collector 113, Units 110 and 110 '.

In the method of manufacturing a nanomembrane through the electrospinning device 100, the polymer spinning solution filled in the spinning liquid main tank 120 is continuously and quantitatively supplied to the nozzle block 111 to which a high voltage is applied through the metering pump, The polymer spinning solution supplied to the nozzle block 111 is radiated and focused on the collector 113 to which a high voltage is applied on the base material 115 conveyed in the electrospinning device 100 through the nozzle 111a A nanomembrane is laminated.

At this time, in the electrospinning apparatus 100, the substrate 115 is conveyed by the conveyance belt 116a rotated between the conveyance rollers 116b.

When the nanomembrane prepared by electrospinning the polymer spinning solution through the electrospinning device as described above is applied to a filter material used in an industrial field, the basis weight of the entire nanomembrane used as the filter material must be constant and uniform, It is possible to produce and sell the products satisfactorily. According to the filter used in the gas turbine of the thermal power plant, depending on the direction of the air flow, the position of the air inflow portion, the direction of the air exhaust portion and the position of the exhaust portion, It is necessary that the basis weight of the nanomembrane constituting the filter membrane is not necessarily constant. On the other hand, in the filter section where air filtration is active, the basis weight of the nanomembrane must be controlled to improve the air filtering efficiency, Since the air flow rate is not so large, the basis weight of the nanomembrane is greatly adjusted There is a need for a design that is more durable than the air filtration side.

Thus, the basis weight of the nanomembrane is required to be a nanomembrane material having different basis weights on the same nanomembrane depending on the positions of the air inlet and outlet.

Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a nanomembrane different in basis weight in the CD direction from the plane direction of the nanomembrane layer in order to improve abrasion resistance and productivity at the time of manufacturing the nanomembrane, The purpose.

The present invention relates to a method of manufacturing a nanomembrane using bottom-up electrospinning, comprising the steps of: forming a nanomembrane having different basis weights of nanofibers in a CD direction, which is produced by an on- Of the present invention.

In addition, it is also possible that the gradient of the basis weight in one direction of the CD direction is increased, or the slope of the basis weight is increased or decreased in both directions, or alternatively, the basis weight of the nanofiber in the CD direction is designed to be different. A method for producing a membrane is provided.

In addition, the present invention provides a nanomembrane produced by the above-described method.

The present invention provides a nanomembrane which improves durability and productivity of nanofiber production by providing a nanomembrane different in basis weight in the CD direction, and a method of manufacturing the same.

1 is a side view schematically showing a nanomembrane electrospinning device,
2 is a plan view schematically showing a nozzle body arranged in a nozzle block of a nanomembrane electrospinning apparatus according to the present invention,
FIG. 3 is a perspective view schematically showing a nozzle body arranged in a nozzle block of a nanomembrane electrospinning apparatus according to the present invention. FIG.
FIG. 4 is a side view schematically showing a nozzle body arranged in a nozzle block of the nanomembrane electrospinning apparatus according to the present invention. FIG.
FIGS. 5 to 6 show an operation process of electrospinning the polymer spinning solution on the same plane of the base material through the nozzles of the respective nozzle tubes of the nanomembrane electrospinning apparatus according to the present invention (the nozzles shown by broken lines in FIG. And the nozzle indicated by the broken line in Fig. 6 is located at the lower part of the substrate)
FIGS. 7 to 9 are plan views of a nanomembrane having a basis weight in the CD direction according to the present invention. FIG.

An electrospinning device for manufacturing and producing nanofibers includes a spinning liquid main tank filled with spinning solution, a metering pump for supplying a fixed amount of spinning solution, a nozzle block having a plurality of nozzles for discharging spinning solution, And a voltage generating device for generating a voltage and a collector for accumulating the fibers that are positioned at the lower end of the nozzle and emit radiation.

The electrospinning device having the above-described structure includes a spinning liquid main tank filled with a spinning solution, a metering pump for supplying a fixed amount of the polymer spinning solution filled in the spinning solution main tank, and a polymer spinning solution in the spinning solution main tank A nozzle block having a plurality of nozzles arranged in a pin shape and arranged to discharge the polymer solution, and a collector disposed at an upper end of the nozzle and spaced apart from the nozzle by a predetermined distance in order to accumulate the polymer solution, And a unit including the apparatus.

A method of manufacturing a nanomembrane through such an electrospinning device is characterized in that a spinning solution in a spinning liquid main tank filled with a spinning solution is continuously and quantitatively supplied in a plurality of nozzles to which a high voltage is applied through a metering pump, Is formed on a collector on which a high voltage is applied through a nozzle to form a nanomembrane on a long sheet conveyed to the units of the electrospinning device, After the sheet passes through each unit, the nanofibers are repeatedly laminated and then laminated, embossed or heat-pressed, or needle-punched to form a nanomembrane.

Here, the electrospinning device is divided into a bottom-up electrospinning device, a top-down electrospinning device, and a horizontal electrospinning device depending on the direction on the collector. That is, the electrospinning device has a configuration in which the collector is located at the upper end of the nozzle, and a bottom-up electrospinning device capable of producing a uniform and relatively thinner nanomembrane, a collector is disposed at the lower end of the nozzle, A top-down electrospinning device capable of increasing the production amount of nanofibers per unit time, and a horizontal electrospinning device having a collector and nozzles arranged in a horizontal direction.

In the bottom-up electrospinning device, a spinning solution is injected through a nozzle of an upward nozzle block, and a spinning solution to be injected is deposited on a lower surface of the support to form a nanomembrane.

According to the above-described configuration, the elongated sheet, in which the spinning solution is sprayed through one of the nozzles of the bottom-up electrospinning device to form the nanomembrane, is transferred into the other unit and transferred into the other unit The nanomembrane is manufactured by repeatedly performing the above-described processes such as spraying a spinning solution through a nozzle on a long sheet and again forming a laminate of nanofibers.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the scope of the present invention, but is merely an example, and various modifications can be made without departing from the technical spirit of the present invention.

The nanofiber generally means a fiber having an average diameter of 50 to 1000 nm or less and can be manufactured using an electrospinning device.

The electrospinning apparatus includes a power supply, a spinning nozzle, a collector, and the like. The power supply forms an electric field of high voltage between the nozzle and the collector. The spinning nozzle supplies spinning solution to the spinning space. The collector concentrates the electrospun nanofibers. The filaments formed in the spinning space of the electrospinning device may have various average diameters depending on spinning conditions, and may be nanofibers having an average diameter of 50 to 1000 nm.

The laminating method of the present invention is generally applicable to all cases where two or more sheets having a thin thickness are pressed and bonded, and appropriate technical effects can be exhibited depending on the use thereof.

An adhesive layer is formed on the lower surface of the fabric and a nano-membrane layer is formed below the adhesive layer. The nanomembrane layer can be made of nanofibers. Since the nanofibers are fibers having an average diameter of 50 to 1000 nm, the pore size can be controlled by adjusting the thickness of the nanofibers. The nano fiber layer may be made of a polymer resin such as polyurethane, polyvinylidene fluoride or nylon. The nanofiber layer is made of two or more polymers having different melting temperatures, and it is also possible to control the size of the pores by melting the nanofibers composed of at least one of the polymers.

In the process of manufacturing a nanomembrane using the laminating method according to the present invention, an adhesive fluid is prepared by dissolving an adhesive material in a solvent, and an adhesive layer is formed on one side of the fabric by electrospinning the adhesive fluid. The nanomembrane on which the adhesive layer is formed is laminated to produce a nanomembrane.

FIG. 2 is a plan view schematically showing a nozzle body arranged in a nozzle block of a nanomembrane electrospinning apparatus according to the present invention, and FIG. 3 is a cross-sectional view of a nozzle body of a nanomembrane electrospinning apparatus according to the present invention, 4 is a side view schematically showing a nozzle body arranged in a nozzle block of a nanomembrane electrospinning apparatus according to the present invention, and FIGS. 5 to 6 are views each showing a side view of the nanomembrane electrospinning apparatus according to the present invention. FIG. 2 is a plan view schematically showing an operation process in which a polymer spinning solution is electrospun on the same plane of a substrate through a nozzle of a nozzle tube. FIG.

Referring to FIG. 1, an electrospinning apparatus 100 according to the present invention includes a bottom-up electrospinning apparatus and at least one unit 110 or 110 '. In one embodiment of the present invention, the electrospinning device 100 is a bottom-up electrospinning device, but it may also be a top-down electrospinning device.

Here, the units 110 and 110 'include a spinning liquid main tank 120 filled with a polymer spinning solution and a metering pump (not shown) for supplying a polymer spinning solution filled in the spinning solution main tank 120 in a fixed amount And a plurality of nozzle tubes 112 having a plurality of nozzles 111a in the form of pins are arranged in the width direction of the substrate 115 so as to discharge the polymer solution in the spinning solution main tank 120 A collector 113 disposed at a predetermined interval from the nozzle 111a to collect the polymer spinning solution injected from the nozzle block 111 and the nozzle 111a and a voltage generator 113 for generating a high voltage to the collector 113, And a device 114. [

As described above, the nanomembrane electrospinning device 1 is continuously supplied with a predetermined amount of the polymer spinning solution filled in the spinning liquid main tank 120 into the nozzle block 111 to which a high voltage is applied through the metering pump, The polymer spinning solution supplied to the block 111 is radiated and focused onto the substrate 113 transferred in the electrospinning device through the nozzle 111a on the collector 113 with a high voltage applied thereto, do.

At least one or more units 110 and 110 'provided in the nanomembrane electrospinning device 1 are sequentially spaced apart from each other by a predetermined interval and the polymer spinning solution is supplied through the units 110 and 110' Thereby producing a nanomembrane.

The nozzle block 111 of the electrospinning apparatus 100 includes a plurality of nozzle tubes 112 arranged in the width direction thereof and a spinning liquid main tank for supplying a polymer spinning solution to the nozzle tubes 112 120 are connected to each other.

The nozzle tubes 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, and 112i, which are linearly formed on the upper surface of the nozzle block 111 and have a plurality of nozzles 111a linearly, A plurality of nozzle tubes 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i are arranged in the width direction of the substrate 115 in the width direction of the substrate 115, And the polymer spinning solution filled in the spinning solution main tank 120 is supplied.

Here, the nozzle tubes 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, and 112i are connected to the spinning solution main tank 120 through a solution supply tube 121, A plurality of nozzle tubes 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i and a spinning liquid main tank 120 are branched.

At this time, a supply amount adjusting means (not shown) is connected to the solution supply pipe 121, which is communicated to the nozzle tubes 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i in the spinning liquid main tank 120, And the supply amount adjusting means is composed of a supply valve 122.

A supply valve 122 is provided in the solution supply pipe 121 which is communicated to each nozzle body 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i in the spinning liquid main tank 120 112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i in the spinning liquid main tank 120 by the supply valves 122, And controlled on-off systems.

That is, when the polymer spinning solution is supplied to the nozzle tubes 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i from the spinning solution main tank 120 through the solution supply tube 121, By the opening and closing of the supply valve 122 provided in the solution supply pipe 121 for supplying the main tank 120 and the nozzle tubes 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, The nozzle tubes 112b, 112d, 112f, 112g, 112h, 112i at specific positions among the nozzle tubes 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i arranged in the nozzle block 111 112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i, 112f, 112g, 112h, 112i, 112f, 112h, 112h, 112h, The supply of the polymer solution is controlled and controlled.

For this purpose, the supply valve 122 is preferably controllably connected to a control unit (not shown). Preferably, the opening and closing of the supply valve 122 is automatically controlled by the control unit. However, It is also possible that the opening and closing of the supply valve 122 is manually controlled.

112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i in the spinning liquid main tank 120. However, The supply amount adjusting means may be composed of various other structures and means, but the present invention is not limited thereto.

The solution supply pipe 121 is connected to the spinning solution main tank 120 and the nozzle tubes 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h and 112i, A supply valve 122 is provided at each of the nozzles 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i in the spinning liquid main tank 120 to supply a plurality of 112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i arranged in the nozzle block 111 by opening the specific supply valve 122 of the supply valve 122, The nozzle tubular body 112a (112a, 112b, 112d, 112f, 112g, 112h, 112i) at the specific position among the nozzle tubular bodies provided in the nozzle block 111 by supplying the polymer solution, , 112c, and 112e of the spinning liquid main tank 120 are blocked by the opening and closing of the supply valve 122, The supply of the polymer spinning solution to be supplied to the (112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i) is adjusted and controlled.

The polymer spinning solution supplied to the nozzle tubes 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i through the solution supply tube 121 in the spinning solution main tank 120 flows through the solution supply tube 121, 112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i through a nozzle supply pipe 125 which is connected to the nozzles 121a.

That is, the nozzles 111a provided in the solution supply pipe 121 and the nozzle tubes 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h and 112i are provided as nozzle supply pipes 125, The supply pipe 125 is branched so as to correspond to the number of the nozzles 111a.

Here, the nozzle supply pipe 125 is provided with a dose adjusting means (not shown), and the dose adjusting means comprises a nozzle valve 126.

The supply of the polymer solution to be supplied to each nozzle 111a from the nozzle supply pipe 125 is controlled individually by the nozzle valve 126 by the opening and closing of the nozzle valve 126, Preferably, the nozzle valve 126 is controllably connected to a control unit (not shown), and the opening and closing of the nozzle valve 126 is automatically controlled by the control unit. However, It is also possible that the opening and closing of the nozzle valve 126 are manually controlled.

In an embodiment of the present invention, if the amount of the spinning solution of the polymer spinning solution is easily controlled and controlled after being supplied to the nozzle 111a from the nozzle tube, the spinning amount adjusting means is composed of the nozzle valve 126, But the present invention is not limited thereto.

According to the structure described above, the solution supply pipe 121 and the nozzles 111a are connected to each other, and the nozzle valve 126 is provided in the nozzle supply pipe 125, Of the plurality of nozzle valves 126 when supplying the polymer spinning solution to the respective nozzles 111a through the respective nozzle tubes 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, The polymer spinning solution is selectively discharged only from the nozzles 111a at specific positions among the nozzles 111a provided in the nozzle tubes 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, Or a specific nozzle valve 126 is closed so that the nozzles 111a provided in the nozzle tubes 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, The nozzle tubular body 112a, the tubular body 112a, the tubular body 112a, and the nozzle body 112b are separated from the spinning liquid main tank 120 by the nozzle valve 126, 112b, 112c, 112d, 112e, 112f, 112g, 112h, and 112i, the supply of the polymer spinning solution supplied to each nozzle 111a is individually controlled and controlled.

In an embodiment of the present invention, the solution supply pipe 121 is provided with a supply valve 122 so that the nozzle tubes 112a, 112b, 112c, 112d and 112e of the nozzle block 111 in the spinning liquid main tank 120 112b, 112c, 112d, 112f, 112g, 112h, and 112i, and a nozzle valve 126 is provided in the nozzle supply pipe 125 to adjust the supply amount of the polymer solution, 112b, 112c, 112d, 112e, 112f, 112c, 112d, 112e, 112f, 112f, 112g, 112h, 112i to regulate and control the radiation amount of the polymer spinning solution which is radiated through each nozzle 111a, 112a, 112b, 112g, 112h, and 112i, the nano membranes having different weights in the width direction of the base material 115 are stacked by the polymer spinning solution electrospunning from the respective nozzles 111a of the nozzle blocks 111, 111a are arranged, the respective nozzles 111a are directly controlled and controlled individually The nanomembranes having different basis weights may be laminated in the width direction of the substrate 115 by controlling and controlling the spinning amount of the polymer spinning solution electrospun through each of the nozzles 111a, but the present invention is not limited thereto.

The MD direction used in the present invention means a machine direction, and means a longitudinal direction corresponding to the progress direction in the case of continuously producing fibers such as a film or a nonwoven fabric, and the CD direction means a perpendicular direction to the MD direction as a cross direction . MD is the machine direction / longitudinal direction, and CD is the width direction / transverse direction.

Basis Weight or Grammage is defined as the mass per unit area, that is, the preferred unit, grams per square meter (often referred to as gsm rather than g / m2).

An on-off system based on an independent nozzle block can control the basis weight of the polymer solution stacked on the substrate differently. Usually, the basis weight of the nanomembrane layer can be appropriately selected depending on the application, but the basis weight is in the range of 1 to 12 g / m 2.

Hereinafter, the polymer used in the present invention will be described. Polymers of the present invention and polyvinylidene fluoride, polyurethane and nylon are preferable for the polymer.

The polymer may be at least one selected from the group consisting of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, or a composite composition thereof, a polyurethane, a polyamide, a polyimide, a polyamideimide, a poly (meta-phenylene isophthalate Amide), meta-aramid, polyethylene chlorotrifluoroethylene, polychlorotrifluoroethylene, polymethylmethacrylate, polyacrylonitrile, polyvinylidene chloride, polyvinylidene chloride-acrylonitrile copolymer, polyacrylic Amide, and the like.

First, the polyamide used in the present invention will be described.

Polyamide refers to a generic term for a polymer linked by an amide bond (-CONH-), which can be obtained by condensation polymerization of a diamine and a dicarboxylic acid. Polyamides are characterized by amide bonds in the molecular structure, and their physical properties vary depending on the ratio of amide groups. For example, when the ratio of amide groups in the molecule is increased, specific gravity, melting point, absorbency, rigidity and the like are increased.

In addition, polyamide is a material used in a wide range of fields such as clothing, tire cord, carpet, rope, computer ribbon, parachute, plastic and adhesive due to its excellent resistance to corrosion, abrasion resistance, chemical resistance and insulation.

Generally, polyamides are classified into aromatic polyamides and aliphatic polyamides. Representative aliphatic polyamides include nylon. Nylon is originally a trademark of DuPont, Inc., but is now used as a generic name.

Nylon is a hygroscopic polymer and is sensitive to temperature. Representative nylons include nylon 6, nylon 66, and nylon 46.

First, nylon 6 is characterized by excellent heat resistance, moldability and chemical resistance, and is produced by ring-opening polymerization of ε-caprolactam in order to produce it. Nylon 6 means that caprolactam has 6 carbon atoms.

(Scheme 1) Nylon 6 polymerization of caprolactam

On the other hand, nylon 66 is generally similar in properties to nylon 6, but is superior in heat resistance to nylon 6 and superior in self-extinguishing and abrasion resistance. Nylon 66 is prepared by dehydration condensation polymerization of hexamethylenediamine and adipic acid.

(Scheme 2) Dehydration condensation of hexamethylenediamine with adipic acid Nylon 66 polymerization by polymerization

Nylon 46 is also excellent in heat resistance, mechanical properties and impact resistance, and has a high processing temperature. Nylon 46 is prepared by polycondensation of tetramethylenediamine and adipic acid. Diaminobutane (DAB), a raw material, is prepared from the reaction of acrylonitrile with hydrogen cyanide. In the first stage of the polymerization operation, a salt is formed from diaminobutane and adipic acid, and the mixture is polymerized under appropriate pressure The prepolymer is converted into a prepolymer and the solid of the prepolymer is polymerized at a solid state by treatment at about 250 ° C in the presence of nitrogen and water vapor.

Nylon 46, in particular, is characterized by a high amide concentration and a regular arrangement between the methylene and amide groups. The melting point of nylon 46 is about 295 ° C, which is higher than that of other types of nylon, and has attracted attention as a resin having excellent heat resistance due to the above characteristics.

The present invention provides a nanomembrane having different basis weights in the CD direction on a substrate using the polyamide, and a method for producing the same.

The polyvinylidene fluoride used in the present invention will now be described. The polyvinylidene fluoride (PVDF) resin is one of the fluoro-based polymers, and the fluororesin contains fluorine, which is excellent in thermal and chemical properties. In producing a spinning solution in which polyvinylidene fluoride is dissolved in an appropriate organic solvent, the polyvinylidene fluoride includes a homopolymer of vinylidene fluoride or a copolymerized polymer containing vinylidene fluoride in a molar ratio of 50% or more , A homopolymer is more preferable from the viewpoint of excellent strength of the polyvinylidene fluoride resin. When the polyvinylidene fluoride resin is a copolymer polymer, known copolymerizable monomers copolymerized with vinylidene fluoride monomers may be suitably used For example, fluorine-based monomers and chlorine-based monomers can be suitably used.

The weight average molecular weight (Mw) is not particularly limited, but is preferably 10,000 to 500,000, more preferably 50,000 to 500,000, and when the weight average molecular weight of the polyvinylidene fluoride resin is less than 10,000, The fibers can not obtain sufficient strength. When the number average molecular weight exceeds 500,000, the handling of the solution is not easy, and the processability is deteriorated, making it difficult to obtain uniform nanofibers.

Among the polymers to be used in the present invention, polyacrylonitrile may be preferably used.

Generally, polyacrylonitrile (PAN) refers to a polymer of acrylonitrile (CH2 = CHCN).

(Reaction formula 3) The unit of polyacrylonitrile

Here, the polyacrylonitrile resin is a copolymer made from a mixture of acrylonitrile and a monomer constituting the majority. Frequently used monomers include butadiene styrene vinylidene chloride or other vinyl compounds. The acrylic fiber contains at least 85% acrylonitrile, and the mode acrylic contains 35 to 85% acrylonitrile. When other monomers are included, the fiber has the property of increasing the affinity to the dye. More specifically, in the production of an acrylonitrile-based copolymer and spinning solution, in the case of producing an acrylonitrile-based copolymer, there is little contamination of nozzles in the course of manufacturing ultrafine fibers by electrospinning, Thereby increasing the solubility in the solvent and imparting better mechanical properties. In addition, polyacrylonitrile has a softening point of 300 ° C or more and is excellent in heat resistance.

The degree of polymerization of the polyacrylonitrile is preferably 1,000 to 1,000,000, and more preferably 2,000 to 1,000,000.

The polyacrylonitrile is preferably used within a range that satisfies the usage amount of the acrylonitrile monomer, the hydrophobic monomer and the hydrophilic monomer. When the polymer is polymerized, the weight% of the acrylonitrile monomer is too low to be electrospun when the weight% of the hydrophilic monomer and the weight% of the hydrophobic monomer are 3: 4 and the total monomer is less than 60, It is difficult to form a stable jet (JET) at the time of electrospinning as well as to cause contamination of the nozzle. If the ratio is more than 99, the spinning viscosity is too high to spin, and even if an additive capable of lowering the viscosity is added, the diameter of the microfine fibers becomes too large and the productivity of electrospray is too low to achieve the object of the present invention.

In addition, as much amount of comonomer is added to the acrylic polymer, the amount of the crosslinking agent must be increased so that the stability of electrospinning can be secured and deterioration of the mechanical properties of the nanofiber can be prevented.

The hydrophobic monomer may be an ethylene-based compound such as methacrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, vinyl acetate, vinyl pyrrolidone, vinylidene chloride or vinyl chloride, It is preferable to use at least one selected.

Wherein the hydrophilic monomer is selected from the group consisting of acrylic acid, allyl alcohol, methallyl alcohol, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, butanediol monoacrylate, dimethylaminoethyl acrylate, butent ricarboxylic acid, vinyl It is preferable to use at least one selected from ethylene-based compounds such as sulfonic acid, allylsulfonic acid, methallylsulfonic acid, and para-styrenesulfonic acid and polyvalent acids or derivatives thereof.

As the initiator to be used for preparing the acrylonitrile-based polymer, an azo-based compound or a sulfate compound may be used, but it is generally preferable to use a radical initiator used for the oxidation-reduction reaction.

Among the polymers used in the present invention, polyethersulfone can also be preferably used.

In general, polyethersulfone (PES) is an amber transparent, amorphous resin having the following repeating unit, and is generally produced by condensation polymerization of dichlorodiphenylsulfone.

(Reaction formula 4) The unit of polyether sulfone

Polyethersulfone is a super heat resistant engineering plastic developed by ICI in the UK. It is a highly heat resistant polymer among thermoplastic plastics. Since the polyethersulfone is amorphous, the physical properties of the polyether sulfone are not lowered by temperature rise, and the temperature dependency of the flexural modulus is small, so that it hardly changes at -100 to 200 캜. The load-strain temperature is 200 to 220 占 폚, and the glass transition temperature is 225 占 폚. In addition, the creep resistance up to 180 占 폚 is the most excellent among the thermoplastic resins, and has the characteristic of being resistant to hot water and steam at 150 to 160 占 폚.

Due to such characteristics, polyethersulfone is used in optical disks, magnetic disks, electric and electronic fields, hydrothermal fields, automobile fields, and heat resistant paints.

Examples of the solvent usable with the polyethersulfone include acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide (DMF), dimethylacetamide (DMAc), N- N-methyl pyrrolidone (NMP), cyclohexane, water, or a mixture thereof, but the present invention is not limited thereto.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples. However, the embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art.

The physical property values in the examples were measured by the following methods.

Basis [gsm]

Six specimens of 200 mm (MD) x 50 mm (CD) were taken from the nanofiber layer. On the other hand, the sampling sites were randomly selected from each of the different weights by an on-off control system. Subsequently, each of the test specimens thus obtained was measured for weight (g) by using a top dish electronic balance. The average mass of each specimen was determined. The mass (g) per 1sm was converted from the obtained average value, and the first digit of the decimal point was rounded off to obtain the basis weight [gsm] of the nanofiber layer sample

Example 1

A polyurethane solution having a weight average molecular weight of 157,000 is dissolved in dimethylformamide (DMF) to prepare a polyurethane solution. The polyurethane solution was put into each of the spinning liquid main tanks, and the applied voltage was applied to the nozzle block including the on-off system designed to separate the two nozzle blocks in the CD direction and to be connected to the independent main tanks respectively at 20 kV, 3 g / m < 2 >. On the electrospinned collector, polyurethane nanofibers having a basis weight of 2 g / m 2 in one direction in the CD direction and 1 m in the other direction are formed in the direction of the CD in a direction of 1 m in the direction of the CD with a basis weight of 5 g / A polyurethane nanomembrane was prepared. At this time, bottom-up electrospinning was performed under the condition that the distance between the electrode and the collector was 40 cm and the temperature was 22 ° C.

Example 2

A polyurethane solution having a weight average molecular weight of 157,000 is dissolved in dimethylformamide (DMF) to prepare a polyurethane solution. The polyurethane solution was put into each of the spinning liquid main tanks and the applied voltage was applied at 20 kV to the nozzle block including the on-off system designed so that the nozzle block was divided into three parts in one direction of the CD direction, and a basis weight of 3 g / m 2 Lt; / RTI > substrate. On the electroluminescent collector, polyurethane nanofibers having a basis weight of 5 g / m < 2 > in the middle portion of the CD direction and polyurethane nanofibers having a basis weight of 2 g / m < 2 & Membranes were prepared. At this time, bottom-up electrospinning was performed under the condition that the distance between the electrode and the collector was 40 cm and the temperature was 22 ° C.

Example 3

A polyurethane solution having a weight average molecular weight of 157,000 is dissolved in dimethylformamide (DMF) to prepare a polyurethane solution. The polyurethane solution was put into the spinning liquid main tank and the applied voltage was applied at 20 kV to the nozzle block including the on-off system designed so that the nozzle block was separated into nine parts in one direction of the CD direction, and a weight of 3 g / And then electrospun on the substrate. Polyurethane nanofibers having a basis weight of 2 g / m 2 and a basis weight of 5 g / m 2 and a CD width of 2 m were alternately formed on the electrospun cellulose substrate in the CD direction to form a polyurethane nano- . At this time, bottom-up electrospinning was performed under the condition that the distance between the electrode and the collector was 40 cm and the temperature was 22 ° C.

100: electrospinning device 110, 110 ': unit
111: nozzle block 111a: nozzle
112: nozzle tube body
112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i:
113: collector 114: voltage generating device
115: substrate 115a, 115b, 115c: nanomembrane
116a: conveying belt 116b: conveying roller
120: spinning liquid main tank 121: solution supply pipe
122: supply valve 125: nozzle supply pipe
126: Nozzle valve
a, b, c, d, e, f: different basis weights of nanofibers

Claims (7)

A method of manufacturing a nanomembrane using bottom-up electrospinning, the method comprising: fabricating a bottom-up electrospinning device including a plurality of nozzle tubes in a bottom-
Wherein the weight of the nanofibers in the CD direction is different from that of the nanofibers in the CD direction by controlling the basis weight of the nanofibers by operating the plurality of nozzle tubes with an on-off system.

delete The method according to claim 1,
Wherein the on-off system is designed to increase the gradient of the basis weight in one direction of the CD direction in which the nanofibers are integrated, wherein the basis weight of the nanofibers in the CD direction is different.
The method according to claim 1,
Wherein the on-off system is designed to increase or decrease the slope of the basis weight in both directions of the CD direction in which the nanofibers are integrated. The method of manufacturing a nanomembrane having different weights of nanofibers in the CD direction
The method according to claim 1,
Wherein the on-off system is designed such that the basis weight of the nanofibers is alternately changed in the direction of the CD in which the nanofibers are integrated, wherein the basis weight of the nanofibers in the CD direction is different.
The method according to claim 1,
Wherein the basis weight of the nanofiber is different in the CD direction in the range of 1 to 12 g / m < 2 >.
A nanomembrane produced by the method according to claim 1.

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