KR101635034B1 - Nano fiber filter and method of manufacturing the same - Google Patents

Abstract

The present invention relates to a method of manufacturing a nanofiber filter using bottom-up electrospinning, comprising the steps of: preparing a nanofiber filter having different basis weights of nanofibers in the MD direction, which is made of a bottom- And more particularly to a method of manufacturing a nanofiber filter having different basis weights of the nanofibers in the MD direction, characterized in that the basis weight of the nanofibers is manipulated with an on-off system of a plurality of nozzle tubes. A nanofiber filter, and a filter cartridge.

Description

TECHNICAL FIELD The present invention relates to a nanofiber filter and a method for manufacturing the nanofiber filter.

The present invention relates to a method of manufacturing a nanofiber filter having different basis weights in a planar direction, and more particularly, to a method of manufacturing a nanofiber filter having different basis weights in the MD direction and a nanofiber filter manufactured thereby.

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 biological harmful substances such as dust, fine particles, bacteria particles and 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, the particles and fine particles of the pores of the filter increase the pressure loss of the filter and deteriorate the life of the filter, and it is difficult to filter nano-sized fine particles of 1 micron or less in the conventional filter media .

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 electrostatic 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 .

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 nanofibers through such an electrospinning device is a method in which a spinning liquid in a spinning liquid main tank filled with a spinning liquid is continuously and constantly supplied in a large number of nozzles to which a high voltage is applied through a metering pump, A nanofiber web is formed on a long sheet conveyed to the units of the electrospinning device, and the nanofibers are formed in a laminated structure The long sheets are passed through the respective units and laminated with the nanofibers repeatedly, followed by laminating, embossing, heat-pressing, and needle punching.

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 uniform and relatively fine nanofibers, 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.

The bottom-up electrospinning device has a configuration in which a spinning solution is injected through nozzles of an upward nozzle block, and a spinning solution to be injected is deposited on a lower surface of the support to form nanofibers.

With the above-described configuration, the elongated sheet on which the nanofiber web is laminated by spraying the spinning liquid through the nozzles in one of the units of the bottom-up electrospinning device is transferred to the inside of the other unit, A nanofiber web is produced by repeatedly performing the above-mentioned processes such as spraying a spinning solution through a nozzle onto a long sheet to form a laminate of nanofibers.

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.

In addition, since the technology for spinning conventional nano-nonwoven fabrics is limited to a small-scale operation line focused on a laboratory, there is no concept of dividing the nanofibers in a horizontal direction by using a nozzle block, and in addition, In the case of the filter, the fiber thickness of the entire nano fiber layer of the filter is constant or the basis weight is constant, so that it can be produced and sold satisfying the standard specifications. In the case of the filter used in gas turbine of the thermal power plant, In some cases, the basis weight and thickness of the fibers constituting the filter do not have to be constant depending on the position of the inlet portion, the direction of exhausting, and the position of the exhaust air. In order to increase air filtering efficiency, While the filter section where air filtration is not active, So much there is a need to design the requirement to increase the durability than air filtration side to significantly control the thickness of the nanofiber. Also, in consideration of the efficiency of the filter, the basis weight of the nanofiber is required to have a different basis weight on the same filter depending on the positions of the air inlet and outlet. In addition, the filter cartridge has a corrugated structure in order to widen the surface area. In consideration of filter efficiency, durability and economical efficiency, the corrugated portion and the non-corrugated portion need to be designed differently in diameter and diameter.

In addition, a number of industrial requirements have also required nanofiber filters composed of different types of polymers in the plane of the filter.

Korean Patent No. 10-1162033 Korean Patent No. 10-1382571

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an air filtering apparatus, an air filtering apparatus, It is an object of the present invention to provide a nanofiber filter having a different basis weight in the MD direction among the plane directions of the filter in order to increase the efficiency and productivity of the filter.

The present invention relates to a method of manufacturing a nanofiber filter using bottom-up electrospinning, comprising the steps of: preparing a nanofiber filter having different basis weights of nanofibers in the MD direction, which is made of a bottom- ≪ / RTI >

In addition, the basis weight of the nanofibers is characterized in that a plurality of nozzle tubes are operated by an on-off system. The nanofiber filter is characterized in that the basis weight of the nanofibers is different in the MD direction.

In addition, the on-off system is characterized in that the basis weight is alternately designed in the MD direction in which nanofibers are integrated.

In addition, the present invention provides a nanofiber filter and a nanofiber filter cartridge manufactured by the method.

The present invention provides a method of manufacturing a nanofiber including a temperature control device, thereby providing a spinning method capable of increasing the productivity of the nanofiber by increasing the concentration of the polymer solution while keeping the diameter of the nanofiber constant.

1 is a side view schematically showing an electrospinning device for manufacturing a nanofiber web,
2 is a plan view schematically showing a nozzle body arranged in a nozzle block of an electrospinning apparatus for manufacturing a nanofiber web according to the present invention,
3 is a perspective view schematically showing a nozzle body arranged in a nozzle block of an electrospinning device for manufacturing a nanofiber web according to the present invention,
FIG. 4 is a side view schematically showing a nozzle body arranged in a nozzle block of an electrospinning device for manufacturing a nanofiber web according to the present invention. FIG.
5 to 6 are diagrams illustrating an operation process of electrospinning the polymer spinning solution on the same plane of the base material through the nozzles of each nozzle tube of the electrospinning apparatus for manufacturing a nanofiber web according to the present invention And the nozzle indicated by the broken line in Fig. 6 is located at the lower part of the substrate)
Figures 7 to 8 are plan views of nanofiber webs with different basis weights according to the invention prepared by the present invention.

Air Filter is divided into Pre Filter, Medium Filter, HEPA Filter and ULPA filter. The performance of the filter is mainly eliminated. The performance and evaluation method differ depending on the size of the target dust particle. The Pre Filter is a filter that removes the dust from the filter. Efficiency is indicated by AFI, and AFI 80% is used. Even if only Pre Filter is installed, good air is absorbed. Factory clean room final filter (HEPA It is also used as a pretreatment filter for protecting the filter. Medium Filter is used for the next stage of clean room (pre-filter) or for pre-treatment of final filter. It is not used because of high cost for general residence, but it is used to make factory interior of general clean level. Hepa -filter or more final filter It is used for the previous stage, but fan power ratio is much, but high-efficiency pre-filter is suitable for preprocessing. The HEPA Filter is a final filter used to make a clean room. The dust size is 0.3 micrometer or more fine dust or dust. Efficiency is represented by DOP. DOP 99.97% (at 0.3 micrometer size) It is installed on line, air conditioner, air chamber, etc., and the life of HEPA filter is extended by installing pre-filter in the previous stage. Ulpa Filter is a Final Filter used for super clean room. It is dust or virus of more than 0.1 micrometer size. Efficiency is represented by DOP like HEPA Filter, and DOP 99.9995% and 99.99995% are mainly used.

Since the cost of the filter increases to Pre, Medium, and HEPA, the Mdeium or HEPA Filter is not used alone in the industrial field. In order to protect against large dust particles and to prolong the service life, Pre, Medium, Use HEPA in order.

In addition, the type of HEPA Filter to be applied depends on the class of the Clean Room, and ULPA is used in super clean room where ultra-precision semiconductor is produced.

In the industrial field, other kinds of filters are used to increase the lifetime and efficiency of the filter. In addition, the present invention can control the basis weight and fiber diameter of the nanofiber filter according to the position and direction of the air, A filter manufactured by a method of manufacturing a nanofiber filter having different basis weights in the MD direction among planar directions of the nanofiber filter, and a filter fabricated by the manufacturing method, have been developed in order to improve the filter efficiency and economical efficiency.

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.

FIG. 2 is a plan view schematically showing a nozzle body arranged in a nozzle block of an electrospinning apparatus for manufacturing a nanofiber web according to the present invention. FIG. 3 is a cross- 4 is a side view schematically showing a nozzle body arranged in a nozzle block of an electrospinning apparatus for manufacturing a nanofiber web according to the present invention, and Figs. 5 to 6 are views showing a schematic view of a nano tube body according to the present invention FIG. 3 is a plan view schematically showing an operation process in which a polymer spinning solution is electrospun on the same plane of a base material through nozzles of each nozzle tube of an electrospinning device for producing a fibrous web. 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 a pin are arranged in the longitudinal 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 distance from the nozzle 111a to accumulate 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, (114).

In the electrospinning device 1 for producing a nanofiber web as described above, the polymer spinning solution filled in the spinning solution 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 substrate 115 conveyed in the electrospinning device through the nozzle 111a on the collector 113 with the high voltage applied thereto, .

At least one or more units 110 and 110 'provided in the electrospinning device 1 for manufacturing a nanofiber web are sequentially disposed at predetermined intervals and the polymer solution is supplied through the units 110 and 110' And electrospun to produce a filter material such as a nanofiber web or a nanofiber filter.

The nozzle block 111 of the electrospinning device 100 includes a plurality of nozzle tubes 112 arranged in the longitudinal 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 and 112i are arranged in the longitudinal direction of the substrate 115 in the longitudinal 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 the 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 112, The means for controlling the amount of radiation may be composed of various other structures and means, but 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 nanofiber web having different weights in the longitudinal direction of the base material 115 is laminated by the polymer spinning solution electrospunning from each nozzle 111a of the nozzle block 111, After the nozzles 111a are arranged, the nozzles 111a are directly controlled and controlled individually It is also possible to form and laminate nanofiber webs different in basis weight in the longitudinal direction of the base material 115 by controlling and controlling the amount of spinning of the polymer spinning solution that is electrospun through each of the nozzles 111a.

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 continuous production of fibers such as a film or a nonwoven fabric, and the CD direction means a perpendicular direction to the CD direction as a cross direction . MD is also referred to as machine direction / longitudinal direction, and CD is referred to as 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). In recent years, for the purpose of making the air filter and the unit lighter and more compact, a type of the filter having a smaller depth is required, and if the filter material having the same filtration area is put in the unit, the filter material faces contact each other due to the thickness of the filter material, There has been a problem in that the pressure loss of the air filter unit remarkably increases. To solve this problem, there has been an attempt to reduce the thickness of the filter material for the air filter, that is, to reduce the basis weight. However, such an attempt has been made to reduce the basis weight of the filter, and it is possible to solve the pressure loss of the air filter unit sufficiently when the basis weight is reduced for a specific portion of the filter for each specific industrial field to which the filter is applied. The strength of the filter medium can be maintained.

The basis weight should be measured in accordance with compendial methods, namely ASTM D 756, ISO 536 and EDANA ERT-40.3-90. The equipment required is scissors or die-cutters for sample cutting and precision weighing instruments (balances). The sample is cut to a total area per layer of 100 cm2 with an accuracy of +/- 0.5%. A balance with a sensitivity of 0.001 g is required, which is read and adjusted to within 0.25% of the applied load and has such precision. The sample is conditioned to about 23 ° C. (± 2 ° C.) and about 50% relative humidity for about two hours to reach equilibrium. Weigh and record 10-fold cut samples from a total area of 1000 cm2, i.e., 0.1 m2, on the analytical balance to approximately 0.001 g. (For samples thicker than 1 mm, it is preferable to weigh one layer only, but note if this is the case.) Divide the weight by the sample area (all tested layers) and calculate the basis weight to obtain a basis weight in gsm . All data are recorded for statistical analysis.

Hereinafter, the heat-resistant polymer used in the present invention will be described. The heat-resistant polymer of the present invention and polyvinylidene fluoride and polyamide 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 >

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 nanofiber filter having a different basis weight in the MD 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. The present invention provides a nanofiber filter having a different basis weight in the MD direction on a substrate using the polyvinylidene fluoride, and a method for producing the same.

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

Example 1

A polyvinylidene fluoride solution having a weight average molecular weight of 157,000 is dissolved in dimethylformamide (DMF) to prepare a polyvinylidene fluoride solution. The above-mentioned polyvinylidene fluoride solution was put into the spinning liquid main tank, and the nozzle block including the on-off system designed to separate the nozzle block in the MD direction was applied at an applied voltage of 20 kV, and electrospun on the cellulosic substrate having a basis weight of 30 gsm Respectively. The nanofiber nonwoven fabric electrospun on the cellulose substrate has a vertical width of 180 cm with respect to the MD direction, alternately 20 cm of the polyvinylidene fluoride nanofiber nonwoven fabric has a basis weight of 0.1 gsm, and 5 cm of the polyvinylidene fluoride nano- A polyvinylidene fluoride nanofiber filter having a structure in which the basis weight of the fibrous nonwoven fabric was repeated to 20 gsm was formed and the basis weight of the nanofibers was different in the MD direction. At this time, bottom-up electrospinning was performed under the conditions of a distance between the electrode and the collector of 40 cm, a spinning liquid flow rate of 0.1 mL / h, a temperature of 22 ° C, and a humidity of 20%.

Example 2

A polyvinylidene fluoride solution having a weight average molecular weight of 157,000 is dissolved in dimethylformamide (DMF) to prepare a polyvinylidene fluoride solution. The above-mentioned polyvinylidene fluoride solution was put into the spinning liquid main tank, and the nozzle block including the on-off system designed to separate the nozzle block in the MD direction was applied at an applied voltage of 20 kV, and electrospun on the cellulosic substrate having a basis weight of 30 gsm Respectively. The nanofiber nonwoven fabric electrospun on the cellulose substrate has a vertical width of 180 cm with respect to the MD direction, alternately 20 cm of the polyvinylidene fluoride nanofiber nonwoven fabric has a basis weight of 0.01 gsm, and 5 cm of the polyvinylidene fluoride nano- A polyvinylidene fluoride nanofiber filter having a structure in which the basis weight of the fibrous nonwoven fabric was repeated at 10 gsm was formed and the basis weight of the nanofibers was different in the MD direction. At this time, bottom-up electrospinning was performed under the conditions of a distance between the electrode and the collector of 40 cm, a spinning liquid flow rate of 0.1 mL / h, a temperature of 22 ° C, and a humidity of 20%.

Example 3

A polyvinylidene fluoride solution having a weight average molecular weight of 157,000 is dissolved in dimethylformamide (DMF) to prepare a polyvinylidene fluoride solution. The above-mentioned polyvinylidene fluoride solution was put into the spinning liquid main tank, and the nozzle block including the on-off system designed to separate the nozzle block in the MD direction was applied at an applied voltage of 20 kV, and electrospun on the cellulosic substrate having a basis weight of 30 gsm Respectively. The nanofiber nonwoven fabric electrospun on the cellulose substrate has a vertical width of 180 cm with respect to the MD direction, alternately 20 cm of polyvinylidene fluoride nanofiber nonwoven fabric has a basis weight of 3 gsm and 5 cm of polyvinylidene fluoride nanofiber A polyvinylidene fluoride nanofiber filter having a structure in which the basis weight of the nonwoven fabric was repeatedly 30 gsm was formed to produce a polyvinylidene fluoride nanofiber filter having a different basis weight of the nanofibers in the MD direction. At this time, bottom-up electrospinning was performed under the conditions of a distance between the electrode and the collector of 40 cm, a spinning liquid flow rate of 0.1 mL / h, a temperature of 22 ° C, and a humidity of 20%.

Example 4

The polyvinylidene fluoride nanofiber nonwoven fabric electrospun on the cellulose substrate had a vertical width of 180 cm with respect to the MD direction, the upper 90 cm had a basis weight of 0.1 gsm and the lower 90 cm had a basis weight of 10 gsm. A polyvinylidene fluoride nanofiber filter was prepared under the same conditions.

Example 5

Electrospinning was carried out in the same manner as in Example 1 except that nylon was replaced with nylon solution in which nylon was dissolved in a solvent of dimethylacetamide (DMAc) instead of polyvinylidene fluoride solution.

Example 6

Electrospinning was carried out in the same manner as in Example 2 except that nylon was replaced with a nylon solution in which nylon was dissolved in a solvent of dimethylacetamide (DMAc) instead of polyvinylidene fluoride solution.

Example 7

Electrospinning was carried out in the same manner as in Example 3, except that nylon was replaced with nylon solution in which nylon was dissolved in a solvent of dimethylacetamide (DMAc) instead of polyvinylidene fluoride solution.

Example 8

Electrospinning was carried out in the same manner as in Example 4 except that nylon was replaced with nylon solution in which nylon was dissolved in a solvent of dimethylacetamide (DMAc) instead of polyvinylidene fluoride solution.

Examples 9 to 16

The filter cartridge was fabricated by bending the nanofiber filters prepared in Examples 1-8.

100: electrospinning device, 110, 110 ': unit,
111: nozzle block, 111a: nozzle,
112: nozzle body,
112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, 112i:
113: collector, 114: voltage generator,
115: substrate,
115a, 115b and 115c: nanofiber webs,
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, and d: nanofiber webs having different weights in the MD direction

Claims (6)

A method of manufacturing a nanofiber filter using bottom-up electrospinning, the method comprising: fabricating a bottom-up electrospinning device including a plurality of nozzle tubes in a bottom-
Wherein the plurality of nozzle tubes are designed to have different weights alternately in the MD direction in which the nanofibers are integrated by operating the on-off system, wherein the basis weight of the nanofibers in the MD direction is different.
delete delete delete A nanofiber filter produced by the method of claim 1.
A nanofiber filter cartridge comprising the nanofiber filter of claim 5.

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