KR101479752B1 - Nanofiber filter with excellent heat-resisting property and its method - Google Patents

Abstract

A nanofiber filter with enhanced heat resistance of the present invention is manufactured by electrospinning a heat resistant polymer in order to resolve low thermal stability, which is a flaw of an existing nanofiber filter. The nanofiber filter is manufactured by a continuous process with a gradient in fiber thickness. Therefore, the nanofiber filter is manufactured efficiently and has price competitiveness. The nanofiber fiber filter has increased filtering efficiency, high efficiency, and heat resistance, and is highly functional. The nanofiber filter includes: a heat resistant polymer nanofiber nonwoven fabric of which a diameter is 250-500 nm; and a heat resistant polymer nanofiber nonwoven fabric of which a diameter is 50-250 nm. The heat resistant polymer is polyethersulfone.

Description

[0001] The present invention relates to a nanofiber filter having improved heat resistance and an excellent heat-resisting property and its method,

The present invention relates to a heat-resistant polymer nanofiber filter having improved heat resistance and a method of manufacturing the same. More specifically, the present invention relates to a heat-resistant polymer, preferably polyacrylonitrile (PAN) or polyethersulfone (PES The present invention relates to a nanofiber filter having improved heat resistance in which heat-resistant polymer nanofibers are successively laminated by electrospinning a solution of a heat-resistant polymer nanofibers and a method for manufacturing the same.

Generally, a filter is a filtration device for filtering foreign matters in a fluid, and is divided into a liquid filter and an air filter. Among them, the air filter is used to prevent the defect of high-tech products as well as the development of high-tech industries. The air filter is used in a clean room where the biologically harmful substances such as dust, fine particles, biological particles such as bacteria and mold, bacteria, The installation of the room is spreading day by day. Cleanroom applications include semiconductor manufacturing, computer equipment assembly, tape manufacturing, printing painting, hospitals, pharmaceutical manufacturing, food processing plants, agriculture, forestry and fisheries.

The air filter forms a porous layer having a microporous structure on the surface of the filter medium, thereby performing a function of preventing the dust from penetrating into the filter medium and performing filtration. However, particles having a large particle size are formed by a filter cake on the surface of the filter medium, and fine particles pass through the primary surface layer and gradually accumulate in the filter medium, thereby blocking the pores of the filter. As a result, it is difficult to filter fine particles of nano-sized particles of 1 micron or less in the conventional filter media as well as to increase the pressure loss of the filter and reduce the life of the filter. .

On the other hand, the efficiency of the conventional air filter is measured by the principle that the static electricity is given to the fibrous aggregate constituting the filter filter material and the particles are collected by the electrostatic force. However, the recent European air filter classification standard EN779 has been revised to exclude the filter efficiency due to the static effect in 2012, so that the actual efficiency of the conventional filter is lowered by more than 20%.

In addition, due to the adverse effects of glass fiber, which has been used as a material of conventional heat-resistant filter, on the environment, in Europe and the United States, the use of glass fiber is regulated for environmental stability.

In order to solve the above problems, various methods of fabricating nano-sized fibers and applying them to filters have been developed. When the nanofibers are implemented in a filter, they have a larger specific surface area than conventional filter media having a large diameter, have flexibility for surface functional groups, and have a nanoparticle pore size, so that harmful fine particles and gas can be efficiently removed .

However, the implementation of the filter using the nanofibers raises the production cost, and it is not easy to control various conditions for production, and since it is difficult to mass-produce the filter, the filter using the nanofibers has a relatively low unit price It is a fact that production can not be spread. Furthermore, currently, filters used in gas turbines, furnaces, and the like require heat resistance.

In addition, the technology for spinning conventional nano-nonwoven fabrics is limited to a small-scale working line focused on laboratories, and there was no concept of dividing the spinning block into units or blocks. In this case, only nano-woven fabrics having a constant fiber thickness were emitted. This has a problem in that the air permeability and life time limit are used when the filter is used as a filter.

The present invention relates to a heat resistant polymer spinning solution obtained by dissolving a heat resistant polymer composed of polyacrylonitrile or polyethersulfone in an organic solvent as an electrospinning device, a heat resistant polymer nanofiber nonwoven fabric having a large fiber thickness and a heat resistant polymer nanofiber nonwoven fabric having a small fiber thickness Heat-resistant polymer nanofiber filter manufactured by electrospinning to produce a heat-resistant polymer nanofiber filter which has a gradient of fiber thickness and has a low pressure loss while having fine pores, and which can realize a high-efficiency and heat-resistant polymer nanofiber filter And a method for producing the same.

According to a preferred embodiment of the present invention, a cellulose substrate; A heat-resistant polymer nanofiber nonwoven fabric having a fiber diameter of 250 to 500 nm formed by electrospinning on a cellulose substrate; And a heat-resistant polymer nanofiber nonwoven fabric having a fiber diameter of 50 to 250 nm laminated by electrospinning on a heat-resistant polymer nanofiber nonwoven fabric having a fiber diameter of 250 to 500 nm.

According to another preferred embodiment of the present invention, the heat-resistant polymer uses polyacrylonitrile or polyethersulfone.

According to another preferred embodiment of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: supplying a heat-resistant polymer solution in which a heat-resistant polymer is dissolved in an organic solvent, Forming a heat-resistant polymer nanofiber nonwoven fabric having a fiber diameter of 250 to 500 nm by electrospinning the heat-resistant polymer solution on the cellulose substrate in the nozzle of the front end block of the block; And in the nozzle of the rear end block block, the heat-resistant polymer solution is continuously electrospinned on the heat-resistant polymer nanofiber nonwoven fabric having a fiber diameter of 250 to 500 nm to form a laminate on the heat-resistant polymer nanofiber nonwoven fabric having a fiber diameter of 50 to 250 nm ; And

According to another preferred embodiment of the present invention, by adjusting the intensity of the voltage applied to each block, adjusting the concentration of the spinning liquid, adjusting the gap between the nozzle and the collector, or adjusting the feeding speed of the long sheet, A polyamic acid non-woven fabric non-woven fabric having a different polyamic acid structure is laminated.

According to another preferred embodiment of the present invention, the electrospinning is a bottom-up electrospinning.

The present invention utilizes a heat-resistant polymer as a nanofiber material and thus has excellent heat resistance. By using a continuous electrospinning method, the manufacturing process is efficient and cost-competitive as well as a nanofiber nonwoven fabric can be used as a high efficiency filter .

Further, since the heat resistant polymer nanofiber nonwoven fabric having different thicknesses is provided, there is an advantage that the durability of the filter is good because the pressure loss is small.

1 is a schematic view of a heat-resistant polymer nanofiber filter having improved heat resistance according to the present invention.
Fig. 2 is a process schematic diagram of the electrospinning apparatus used in the present invention.
3 is a schematic process diagram of a block of an electrospinning device used in the present invention.
4 is a schematic view of an apparatus for measuring thickness of an electrospinning apparatus used in the present invention.
5 is a schematic view of a nozzle block and a nozzle of an electrospinning apparatus used in the present invention.

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.

First, an electrospinning device for producing a filter by electrospinning a spinning solution on a substrate will be described with reference to the drawings.

Fig. 1 is a schematic view of a heat-resistant polymer nanofiber filter having improved heat resistance according to the present invention, Fig. 2 is a schematic view of the process of the electrospinning device used in the present invention, Fig. 3 is a cross- Fig. 5 is a schematic view of a nozzle block and a nozzle of the electrospinning device used in the present invention. Fig. 5 is a schematic view of a nozzle block and a nozzle of the electrospinning device used in the present invention.

As shown in the drawing, the electrospinning apparatus 10 of the present invention includes a spinning liquid main tank (not shown) in which a spinning liquid is filled and a weighing device for supplying a fixed amount of the polymer spinning solution filled in the spinning liquid main tank (3) in which a plurality of nozzles (2) in the form of a pin are arranged for discharging the polymer solution for use in the spinning liquid main tank and a pump (not shown), and a nozzle block (20) for accommodating a collector (4) spaced apart from the nozzle (2) by a predetermined distance and a voltage generating device (1a, 1b) for generating a voltage to the collector (4) And a case 8 made of a conductor or a negative conductor in the block 20.

In the present invention, one spinning liquid main tank (not shown) is provided. However, in the case where the spinning liquid is composed of two or more spinning liquids, two or more main spinning liquid main tanks may be provided, or one spinning liquid main tanks It is also possible to divide into two or more spaces and supply two or more polymer spinning solution filled in each divided space.

With the above structure, the electrospinning apparatus 10 is configured such that the spinning liquid filled in the spinning liquid main tank in the block 20 continuously flows into the plurality of nozzles 2 to which a high voltage is applied through the metering pump And the spinning liquid of the polymer supplied to the nozzle 2 is radiated and focused on the collector 4 having a high voltage applied thereto through the nozzle 2 to form a nanofiber nonwoven fabric (not shown) The nanofiber nonwoven fabric is laminated to produce a filter.

A feeding roller 11 is provided at the front end of the electrospinning device 10 for feeding a long sheet (not shown) in which a polymer spinning solution is injected from the block 20 to laminate nanofibers, Up rollers 12 for winding up a long sheet on which fibers are stacked.

The elongated sheet is provided for preventing and transporting the nanofibers. One end and the other end of the elongated sheet are wound around a feeding roller 11 provided at the front end of the electrospinning device 10 and a winding roller 12 provided at the rear end.

On the other hand, the electrospinning apparatus 10 of each of the blocks 20a and 20b is installed in the advancing direction (a) of the long sheet with respect to the collector 4. An auxiliary belt 6 is provided between the collector 4 and the long sheet and a long sheet in which nanofibers are stacked and formed on the respective collectors 4 through the auxiliary belts 6 is formed in a horizontal direction Lt; / RTI > That is, the auxiliary belt 6 rotates in synchronization with the conveyance speed of the long sheet, and has the auxiliary belt roller 7 for driving the auxiliary belt 6. The auxiliary belt roller 7 is an automatic roller having at least two frictional forces. Since the auxiliary belt 6 is provided between the collector 4 and the long sheet, the long sheet is smoothly conveyed without being attracted to the collector 4 to which the high voltage is applied.

With the structure as described above, the spinning solution filled in the spinning liquid main tank in the block 20 of the electrospinning device 10 is sprayed onto the elongate sheet placed on the collector 4 through the nozzle 2 , The spinning liquid sprayed on the long sheet is accumulated, and the nanofiber nonwoven fabric is laminated. The auxiliary belt 6 is driven by the rotation of the auxiliary belt roller 7 provided on both sides of the collector 4 and the elongated sheet is conveyed to be positioned in the block 20b at the rear end of the electrospinning device 10 And the above-described process is repeatedly performed.

5, the nozzle block 3 includes a plurality of nozzles 2 arranged upward from the discharge port, a tube 43 formed of a row of nozzles 2, a spinning solution storage tank 44, And a spinning liquid circulating pipe (45).

First, the spinning liquid storage tank 44 connected to the spinning liquid main tank to receive and store the spinning solution is connected to the nozzle 2 through the spinning liquid circulating pipe 45 by the metering pump (not shown) And the spinning solution is supplied to the spinning solution. Here, the tube 43 having a plurality of nozzles 2 in a row is supplied with the same spinning solution from the spinning solution storage tank 44, but a plurality of spinning solution main tanks are provided, It is also possible to supply a spinning liquid of different kinds to each of the tubes 43 and radiate them.

When radiated from the discharge port of the plurality of nozzles 2, the overflowed solution is moved to the overflow solution storage tank 41. The overflow solution storage tank 41 is connected to the spinning solution main tank so that the overflow solution can be reused for spinning.

Meanwhile, the main controller 30 of the present invention controls the spinning conditions in the process of spinning and controls the amount of spinning solution supplied to the nozzle block 3, and generates a voltage for each block 20a and 20b Controls the voltage of the devices 1a and 1b and controls the feeding speed of each of the blocks 20a and 20b according to the thickness of the nanofiber nonwoven fabric and the long sheet measured by the thickness measuring device 9. [

The thickness measuring device 9 of the present invention is disposed so as to face the long sheets located at the front end and the rear end of the block 20 and having the laminated nanofiber nonwoven fabric therebetween. The thickness measuring device 9 is connected to the main controller 30 for controlling the radiation conditions of the electrospinning device 10 so that the thickness measuring device 9 measures the thickness of the non- The main controller 30 controls the conveying speed of each of the blocks 20a and 20b. For example, in the case of electrospinning, when the thickness of the nanofibers discharged to the block 20a located at the front end portion is measured thinly, the conveyance speed of the block 20b located at the rear end portion is reduced, The thickness of the film is controlled to be constant. In addition, the main controller 30 increases the discharge amount of the nozzle block 3 and controls the voltage intensity of the voltage generators 1a and 1b to increase the discharge amount of the nanofibers per unit area, It is possible to control it uniformly.

The thickness measuring device 9 includes a thickness measurement unit configured to measure a distance between the nanofiber nonwoven fabric in which the nanofiber nonwoven fabric is laminated and the elongated sheet by ultrasonic measurement, and a pair of ultrasonic longitudinal waves and a transverse wave, The thickness of the nanofiber nonwoven fabric and the long sheet is calculated on the basis of the distance measured by the pair of ultrasonic measuring devices, as shown in FIG. More particularly, the present invention relates to a method and a device for measuring the propagation time of longitudinal waves and transverse waves of longitudinal waves and transverse waves, respectively, by projecting ultrasound waves and transverse waves to longitudinal sheets laminated with nanofibers, Measuring the time, measuring a propagation time of the longitudinal wave and the transverse wave and a temperature coefficient of propagation velocity and propagation velocity of the longitudinal wave and the transverse wave at a reference temperature of the long sheet in which the nanofibers are stacked, Is a thickness measuring apparatus for calculating a thickness

The electrospinning apparatus 10 used in the present invention does not change the conveying speed from the initial value when the thickness deviation amount of the nanofiber nonwoven fabric is less than the predetermined value and sets the conveying speed to the initial value It is possible to simplify the control of the conveyance speed by the conveyance speed control apparatus. Further, in addition to the control of the conveying speed, the discharge amount and the voltage intensity of the nozzle block 3 can be adjusted. When the thickness deviation amount is less than the predetermined value, the discharge amount of the nozzle block 3 and the voltage intensity are not changed from the initial value , It is possible to control the amount of discharge of the nozzle block 3 and the intensity of the voltage to be changed from the initial value when the amount of deviation of the nozzle block 3 is equal to or larger than the predetermined value. .

The block 20 of the electrospinning device 10 is divided into a front end block 20a located at the front end portion and a rear end block 20b located at the rear end portion according to the radiation position. In the embodiment of the present invention, the number of blocks is limited to two, but it is also possible to have two or more blocks.

In the present invention, the same polymer spinning solution is radiated in each of the blocks 20a and 20b, but it is also possible to spin different kinds of polymer spinning solution for each block 20a and 20b, It is also possible to emit two or more different kinds of polymer solution. When at least two different types of spinning solutions are supplied and radiated for each of the blocks 20a and 20b, polymer nanofiber nonwoven fabrics of different kinds can be successively laminated.

On the other hand, a laminating device 19 is provided at the rear end of the electrospinning device 10 of the present invention. The laminating device 19 applies heat and pressure through which the elongated sheet and the nanofiber nonwoven fabric are adhered to each other, and then wound on the winding roller 12 to produce a filter.

The electrospinning device 10 can increase the collecting area to uniform the density of the nanofibers and effectively prevent the droplet phenomenon, thereby improving the quality of the nanofibers, The nanofibers and nanofibers thereof can be mass-produced. In addition, since the material and the electrospinning condition can be controlled in the electrospinning in the block 20 having the nozzle 2 having a plurality of pins, the width and thickness of the nonwoven fabric and the filament can be freely changed and adjusted.

In addition, when the polymer is spun as described above, it is most preferable to spin the polymer under environmental conditions of 30 to 40 DEG C and 40 to 70% of the temperature depending on the polymer material.

In the present invention, the diameter of the nanofiber is preferably 30 to 1000 nm, more preferably 50 to 500 nm.

Hereinafter, the heat-resistant polymer used in the present invention will be described. The heat-resistant polymer of the present invention and polyacrylonitrile and polyethersulfone are preferable.

First, the heat-resistant polymer may be at least one selected from the group consisting of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer or a composite composition thereof, a polyamide, a polyimide, a polyamideimide, a poly (meta-phenylene isophthalamide ), Meta-aramid, polyethylene chlorotrifluoroethylene, polychlorotrifluoroethylene, polymethylmethacrylate, polyacrylonitrile, polyvinylidene chloride, polyvinylidene chloride-acrylonitrile copolymer, polyacrylamide, etc. . ≪ / RTI >

Of the heat-resistant 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 Scheme 1) 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 electrospinning 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 heat-resistant 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 2) 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.

In one embodiment of the present invention, polyacrylonitrile or polyethersulfone solution is used as the heat resistant polymer spinning solution, but the heat resistant polymer spinning solution to be used is not limited thereto.

Hereinafter, a method of manufacturing a nanofiber filter having improved heat resistance according to the present invention will be described.

First, in the present invention, a heat-resistant polymer is used as a spinning solution, and a cellulose substrate 100 is used as a long sheet.

The heat-resistant polymer solution obtained by dissolving the heat-resistant polymer in an organic solvent is supplied to the spinning liquid main tank of the electrospinning device 10, and the heat-resistant polymer solution supplied to the spinning liquid main tank is supplied through a metering pump to a nozzle block (3) in a plurality of nozzles (2). The heat-resistant polymer solution supplied from each of the nozzles 2 is electrospun and converged on the cellulose substrate 100 located on the collector 4 with a high voltage applied thereto through the nozzle 2 to form a heat-resistant polymer nanofiber nonwoven fabric .

The heat-resistant polymer is preferably polyacrylonitrile or polyethersulfone. In one embodiment of the present invention, polyacrylonitrile or polyethersulfone solution is used as a spinning solution, but the present invention is not limited thereto.

The cellulose base material 100 in which the heat-resistant polymer nanofibers are laminated in the front end block 20a of the electrospinning device 10 includes a feed roller 11 operated by driving a motor (not shown) Is transferred from the front end block 20a into the rear end block 20b by the rotation of the auxiliary belt 6 driven by the rotation of the roller 11 and the above process is repeated to form the heat resistant polymer A nanofiber nonwoven fabric is formed.

Hereinafter, the cellulose base material 100 will be described. The cellulose base material (100) is characterized by excellent dimensional stability at a high temperature and high heat resistance. The fine cellulosic fibers have a high crystallinity and a high elastic modulus in that they form a fine porous structure, and are essentially excellent in dimensional stability at high temperatures. With this feature, the cellulosic substrate 100 can be used as a high-performance filter, a functional sheet, a living product such as a sheet for cooking or absorbent sheet, a substrate for a semiconductor device or a wiring board, a substrate for a low linear expansion rate material, And the like.

In an embodiment of the present invention, the cellulose base material 100 is used instead of the long sheet, but the present invention is not limited thereto.

The front end voltage generator 1a for supplying a voltage to the front end block 20a applies a low radiation voltage to the cellulose-based substrate 100 to provide a heat-resistant polymer nanofiber nonwoven fabric 200 having a fiber diameter of 250 to 500 nm. And the rear end voltage generating device 1b for supplying a voltage to the rear end block 20b is provided with a high radiation voltage to provide the heat resistant polymer nanofiber nonwoven fabric 300 having a fiber diameter of 50 to 250 nm to the cellulose Heat-resistant polymer nanofiber nonwoven fabric 200 having a fiber diameter of 250 to 500 nm formed on the base material 100.

The radiation voltage given by each of the voltage generating devices 1a and 1b is 1 kV or more, preferably 20 kV or more, and the voltage given by the front-end voltage generating device 1a is given by the rear- Voltage.

In the present invention, a heat-resistant polymer nanofiber nonwoven fabric 200 having a fiber diameter of 250 to 500 nm is laminated on a base material by applying a low voltage to the front end block 20a of the electrospinning device 10, 20b of the heat resistant polymer nanofiber nonwoven fabric 300 having a fiber diameter of 50 to 250 nm is laminated on the heat resistant polymer nanofiber nonwoven fabric 200 having a fiber diameter of 250 to 500 nm, . However, when the heat-resistant polymer nanofiber nonwoven fabric 300 having a fiber diameter of 50 to 250 nm is radiated from the front end block 20a and the heat-resistant polymer nanofiber nonwoven fabric 200 having a fiber diameter of 250 to 500 nm Or may be emitted from the rear end block 20b.

Also, a nanofiber filter in which the number of blocks of the electrospinning device 10 is set to three or more, and three-layered nanofiber nonwoven fabrics having different fiber thicknesses are laminated on a long sheet with different voltages for each block are manufactured It is also possible to do.

It is also possible that the nanofiber nonwoven fabrics having different fiber thicknesses are continuously laminated by varying the intensity of the voltage applied to each of the blocks 20a and 20b. Even in the block 20, It is also possible to form a hybrid nanofiber nonwoven fabric in which two or more polymers are electrospun and laminated by supplying different polymer spinning solutions for each nozzle 2

In addition, the degree width by, but this method of varying the intensity of voltage to be given to each block (20a, 20b) to put the difference in fiber diameter in the use, to adjust the distance between the nozzle (2) and the collector (4) It is possible to form other nanofiber nonwoven fabrics. When the spinning liquid is the same and the supply voltage is the same, the diameter of the fiber becomes thicker as the spinning distance becomes closer, and the fiber diameter becomes smaller as the spinning distance becomes longer. It is also possible that a fibrous nonwoven fabric is formed. The difference in fiber thickness can be determined by adjusting the concentration of the spinning liquid or by adjusting the feeding speed of the long sheet.

In addition, it is also possible to manufacture hybrid nanofiber nonwoven fabrics by constituting two or more kinds of polymers of the spinning solution to be used.

A heat resistant polymer nanofiber nonwoven fabric 200 having a fiber diameter of 250 to 500 nm is laminated on the cellulose substrate 100 and the heat resistant polymer nanofiber nonwoven fabric 200 having a fiber diameter of 250 to 500 nm is coated with a fiber diameter A heat resistant polymer nanofiber nonwoven fabric 300 having a thickness of 50 to 250 nm is laminated and finally a heat resistant polymer nanofiber filter is produced.

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 invention are provided to more fully describe the present invention to those skilled in the art.

Example 1

A polyacrylonitrile solution is prepared by dissolving polyacrylonitrile (Korea-Japan Synthetic Fiber) having a weight average molecular weight of 157,000 in dimethylformamide (DMF). The polyacrylonitrile solution was charged into the spinning liquid main tank and applied to the front end block at an applied voltage of 15 kV and the rear end block at an applied voltage of 20 kV to be electrospun on a cellulose substrate having a basis weight of 30 gsm. In the front end block, a polyacrylonitrile nanofiber nonwoven fabric having a thickness of 2.5 탆 and a fiber diameter of 350 nm was formed on a cellulose substrate. Subsequently, a polyacrylonitrile nano fiber having a thickness of 2.5 탆 and a fiber diameter of 350 nm A polyacrylonitrile nanofiber nonwoven fabric having a thickness of 2.5 탆 and a fiber diameter of 150 nm was laminated on the fibrous nonwoven fabric to prepare a polyacrylonitrile nanofiber filter. At this time, electrospinning was performed under the conditions of a distance between the electrode and the collector of 40 cm, a spinning solution flow rate of 0.1 mL / h, a temperature of 22 ° C, and a humidity of 20%.

Example 2

A polyacrylonitrile solution is prepared by dissolving polyacrylonitrile (Korea-Japan Synthetic Fiber) having a weight average molecular weight of 157,000 in dimethylformamide (DMF). The polyacrylonitrile solution was charged into the spinning liquid main tank, and the applied voltage was applied to the front end block at 15 kV and the applied voltage was applied to the rear end block at 20 kV to electrospray on the cellulose substrate. In the front end block, a polyacrylonitrile nanofiber nonwoven fabric having a thickness of 3 m and a fiber diameter of 350 nm was formed on the cellulose substrate. Subsequently, in the back end block, the polyacrylonitrile nano- A polyacrylonitrile nanofiber nonwoven fabric having a thickness of 2 탆 and a fiber diameter of 150 nm was laminated on the fibrous nonwoven fabric to prepare a polyacrylonitrile nanofiber filter. At this time, electrospinning was performed under the conditions of a distance between the electrode and the collector of 40 cm, a spinning solution flow rate of 0.1 mL / h, a temperature of 22 ° C, and a humidity of 20%.

Example 3

A polyacrylonitrile solution is prepared by dissolving polyacrylonitrile (Korea-Japan Synthetic Fiber) having a weight average molecular weight of 157,000 in dimethylformamide (DMF). The polyacrylonitrile solution was charged into the spinning liquid main tank, and the applied voltage was applied to the front end block at 15 kV and the applied voltage was applied to the rear end block at 20 kV to electrospray on the cellulose substrate. In the front end block, a polyacrylonitrile nanofiber nonwoven fabric having a thickness of 2 탆 and a fiber diameter of 350 nm was formed on a cellulose substrate. Subsequently, in the rear end block, the polyacrylonitrile nano-particles having a thickness of 2 탆 and a fiber diameter of 350 nm A polyacrylonitrile nanofiber nonwoven fabric having a thickness of 3 mu m and a fiber diameter of 150 nm was laminated on the fibrous nonwoven fabric to prepare a polyacrylonitrile nanofiber filter. At this time, electrospinning was performed under the conditions of a distance between the electrode and the collector of 40 cm, a spinning solution flow rate of 0.1 mL / h, a temperature of 22 ° C, and a humidity of 20%.

Example 4

Electrospinning was carried out in the same manner as in Example 1, except that the polyethersulfone solution was changed to a polyethersulfone solution in which polyethersulfone was dissolved in a solvent of dimethylacetamide (DMAc) instead of the polyacrylonitrile solution.

Example 5

Electrospinning was carried out in the same manner as in Example 2, except that the polyethersulfone solution was changed to a polyethersulfone solution in which polyethersulfone was dissolved in a solvent of dimethylacetamide (DMAc) instead of the polyacrylonitrile solution.

Example 6

Electrospinning was carried out in the same manner as in Example 3, except that the polyethersulfone solution was changed to a polyethersulfone solution in which polyethersulfone was dissolved in a solvent of dimethylacetamide (DMAc) instead of the polyacrylonitrile solution.

Comparative Example 1

Nylon 6 was dissolved in formic acid to prepare a nylon 6 solution, and the nylon 6 solution was added to the spinning liquid main tank. A nylon 6 nanofiber having a thickness of 5 탆 and a fiber diameter of 350 nm was electrospun on a cellulose substrate having a basis weight of 30 gs and placed on a collector under the conditions of an applied voltage of 20 kV, a spinning solution flow rate of 0.1 mL / h, a temperature of 22 캜 and a humidity of 20% Filter.

Comparative Example 2

A polyacrylonitrile solution is prepared by dissolving polyacrylonitrile (Korea-Japan Synthetic Fiber) having a weight average molecular weight of 157,000 in dimethylformamide (DMF). The polyacrylonitrile solution was charged into a spinning liquid main tank and electrospun on a cellulose substrate having a basis weight of 30 gs by applying a spinning voltage of 15 kV to obtain a polyacrylonitrile nanofiber nonwoven fabric having a thickness of 5 μm and a fiber diameter of 350 nm . At this time, electrospinning was performed under the conditions of a distance between the electrode and the collector of 40 cm, a spinning solution flow rate of 0.1 mL / h, a temperature of 22 ° C, and a humidity of 20%.

- Evaluation of heat shrinkage

The filters of the examples and comparative examples were cut into 3 cm x 3 cm and stored at 190 ° C for 30 minutes, and the heat shrinkage ratio was evaluated and shown in Table 1.

- Filtration efficiency measurement

The DOP test method was used to measure the efficiency of the fabricated nanofiber filter. The DOP test method measures the dioctyl phthalate (DOP) efficiency with an automated filter analyzer (AFT) of TSI 3160 from TSI Incorporated and measures the permeability, filter efficiency and differential pressure of the filter media material .

The automation analyzer is a device that automatically measures the velocity of air, DOP filtration efficiency, air permeability (permeability), etc. by passing DOP through the filter sheet by making particles of desired size and is a very important device for high efficiency filter.

The DOP% efficiency is defined as:

DOP% transmittance = 1 - 100 (DOP concentration downstream / DOP concentration upstream)

The filtration efficiencies of the examples and comparative examples were measured by the same method as described above, and are shown in Table 2.

Examples 1 to 3 Examples 4 to 6 Comparative Example 1 Comparative Example 2 Heat shrinkage (%) <2 <3 10 4

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 0.35 탆 DOP
Filtration efficiency (%) 98 98.2 98.1 98 98.1 98 90 90.4

It can be seen that the nanofiber filter manufactured through the embodiment of the present invention has excellent heat resistance and filtration efficiency as compared with the comparative example.

- pressure drop and filter life measurement

The pressure drop of the fabricated nanofiber filter was measured with ASHRAE 52.1 according to the flow rate of 50 / / m ³ , and the filter life was measured accordingly. Table 3 shows the comparison between the examples and the comparative examples.

Examples 1 to 3 Examples 4 to 6 Comparative Examples 1 to 2 Pressure drop (in.w.g) <4.2 <4 > 8 Filter life (month) 6.9 6.7 4.1

According to Table 3, the filter manufactured through the embodiment of the present invention has a lower pressure drop due to a lower pressure drop than the comparative example, and has a longer filter life, resulting in superior durability.

Thus, those skilled in the art will appreciate that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

1a, 1b: voltage generating device, 2: nozzle,
3: nozzle block, 4: collector,
6: auxiliary belt, 7: auxiliary belt roller,
8: case, 9: thickness measuring device,
10: electrospinning device, 11: feed roller,
12: take-up roller, 19: laminating apparatus,
20, 20a, 20b: block, 30: main controller,
41: Overflow solution storage tank, 43: Tubular body,
44: spinning liquid storage tank, 45: spinning liquid circulation pipe,
100: cellulose substrate,
200: heat-resistant polymer nanofiber nonwoven fabric,
300: heat-resistant polymer nanofiber nonwoven fabric.

Claims (6)

A cellulose substrate;
A heat-resistant polymer nanofiber nonwoven fabric having a fiber diameter of 250 to 500 nm formed by electrospinning on the cellulose substrate; And
A heat-resistant polymer nanofiber nonwoven fabric having a fiber diameter of 50 to 250 nm laminated by electrospinning on the heat-resistant polymer nanofiber nonwoven fabric having a fiber diameter of 250 to 500 nm;
Wherein the heat-resistant polymer is polyethersulfone, and the heat-resistant polymer is polyethersulfone.
delete Supplying a heat-resistant polymer solution obtained by dissolving a heat-resistant polymer in an organic solvent to a nozzle of each block;
Forming a heat-resistant polymer nanofiber nonwoven fabric having a fiber diameter of 250 to 500 nm by electrospinning the heat-resistant polymer solution on the cellulose substrate in the nozzle of the block of the front end block of the block; And
In the nozzle of the rear end block of the block, the heat-resistant polymer solution is continuously electrospinned on the heat-resistant polymer nanofiber nonwoven fabric having a fiber diameter of 250 to 500 nm to form a laminate on the heat-resistant polymer nanofiber nonwoven fabric having a fiber diameter of 50 to 250 nm step;
Wherein the heat-resistant polymer is polyethersulfone, and the heat-resistant polymer is polyethersulfone.
delete The method of claim 3,
The thickness of the polyether sulfone nanofibers having different fiber diameters may be adjusted by varying the intensity of the voltage applied to each of the blocks, adjusting the concentration of the spinning solution, adjusting the interval between the nozzles and the collector, Wherein the nonwoven fabric is laminated on the nonwoven fabric.
The method of claim 3,
Wherein the electrospinning is a bottom-up electrospinning process.

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