WO2017164112A1 - Air filter medium - Google Patents

Air filter medium Download PDF

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Publication number
WO2017164112A1
WO2017164112A1 PCT/JP2017/010904 JP2017010904W WO2017164112A1 WO 2017164112 A1 WO2017164112 A1 WO 2017164112A1 JP 2017010904 W JP2017010904 W JP 2017010904W WO 2017164112 A1 WO2017164112 A1 WO 2017164112A1
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WO
WIPO (PCT)
Prior art keywords
fine fiber
filter medium
fine
air filter
fibers
Prior art date
Application number
PCT/JP2017/010904
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French (fr)
Japanese (ja)
Inventor
大輔 小森
慶太 高橋
由浩 辻
稲垣　純
港 加藤
玄将 大西
Original Assignee
パナソニックＩｐマネジメント株式会社
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Priority claimed from JP2017036226A external-priority patent/JP2017170429A/en
Application filed by パナソニックＩｐマネジメント株式会社 filed Critical パナソニックＩｐマネジメント株式会社
Publication of WO2017164112A1 publication Critical patent/WO2017164112A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/28—Plant or installations without electricity supply, e.g. using electrets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
    • B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
    • B32B5/26—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary

Definitions

  • the present invention relates to an air filter medium.
  • FIG. 10 is a schematic diagram of a conventional air filter medium in a charged state.
  • the air filter medium 100 obtained by subjecting the nonwoven fabric to charging treatment has fibers having positive charges and negative charges dispersed in a random manner (see, for example, Patent Document 2). ).
  • JP 2008-000682 A JP-A-61-211027
  • an object of the present invention is to provide an air filter medium with improved collection performance by providing a directional electric field on a nonwoven fabric and applying sufficient electrostatic force to dust particles.
  • an air filter medium includes a base material and a fine fiber layer provided on the surface of the base material, and the fine fiber layer includes a plurality of fine fibers. It is a multilayer structure composed of aggregates.
  • the volume resistivity of the polymer forming the fine fibers is 10 ⁇ 16 ⁇ cm or more and the dielectric loss tangent is 0.001 or less, and the charge is distributed to 90% or more of the entire area in the plane direction of each fine fiber aggregate. ing.
  • the fine fibers in the local portion are laminated in the laminating direction with the first fine fiber aggregate having a lot of positive charges and the second fine fiber aggregate having a lot of negative charges. It is characterized by being. This achieves the intended purpose.
  • a collection of fine fibers having positive and negative charges is laminated, so that a high electric field strength having directionality in the lamination direction can be obtained.
  • a fiber can attract a dust particle strongly and can improve a collection efficiency remarkably.
  • FIG. 1 is a schematic cross-sectional view of an air filter medium according to Embodiment 1.
  • FIG. FIG. 2 is a schematic diagram in a charged state of fine fibers of the air filter medium in the first embodiment.
  • FIG. 3 is a schematic diagram in the charged state of the air filter medium in the first embodiment.
  • FIG. 4 is a diagram showing a method for manufacturing the air filter medium in the first embodiment.
  • FIG. 5 is a diagram illustrating a multilayer manufacturing method for an air filter medium in the first embodiment.
  • FIG. 6 is a view of the manufacturing process of the air filter medium according to the second embodiment as viewed from A of FIG.
  • FIG. 7 is a view of the manufacturing process of the air filter medium according to the second embodiment as viewed from B of FIG.
  • FIG. 8 is a view of the spinning trajectory in the first nozzle row of the air filter medium according to the second embodiment as viewed from B in FIG. 5.
  • FIG. 9 is a diagram showing the results of evaluating the fiber diameter, the filter medium collection efficiency, and the state of charge distribution in the examples.
  • FIG. 10 is a schematic view of a conventional air filter medium in a charged state.
  • An air filter medium includes a base material and a fine fiber layer provided on the surface of the base material, and the fine fiber layer is a multilayer structure including a plurality of fine fiber aggregates.
  • the volume resistivity of the polymer forming the fine fiber is 10 ⁇ 16 ⁇ cm or more and the dielectric loss tangent is 0.001 or less, and the charge distribution is distributed over 90% of the entire area of each fine fiber aggregate in the plane direction. . Furthermore, in the laminating direction in the local portion, the first fine fiber aggregate having a lot of positive charges and the second fine fiber aggregate having a lot of negative charges are laminated. It is characterized by that.
  • the air filter medium according to the embodiment of the present invention is characterized in that the first fine fiber aggregates and the second fine fiber aggregates are alternately laminated in three or more layers.
  • the fine fiber layer sandwiched between the uppermost surface and the lowermost surface can have higher electric field strength with respect to the laminating direction of the air filter medium, the fine fibers strongly attract and adsorb dust particles. And the collection efficiency can be remarkably improved.
  • the air filter medium according to the embodiment of the present invention is characterized in that the local bias of the charge is surrounded by the reverse charge in the planar direction and the stacking direction inside the fiber layer assembly. To do.
  • the air filter medium according to the embodiment of the present invention is characterized in that the fine fibers are made of polystyrene.
  • the charged state of the fiber layer can be maintained for a long time.
  • the air filter medium according to the embodiment of the present invention may be composed of fibers having an average fiber diameter of the fine fiber layer of 100 nm to 2000 nm.
  • the smaller the fiber diameter the less resistance the air collides with the fiber during ventilation, so the amount of fiber in the space at the same pressure loss can be increased. That is, as the fiber diameter is thinner, more fibers can be used. For this reason, the pores can be made denser, and the dust particle collection efficiency by mechanical collection can be improved. Furthermore, since the electric field strength between fibers becomes strong, the collection efficiency of dust particles by electrostatic force can be improved. As a result, the collection efficiency can be further improved.
  • FIG. 1 is a schematic cross-sectional view of an air filter medium according to Embodiment 1.
  • FIG. FIG. 2 and FIG. 3 are schematic diagrams in a charged state of fine fibers of the air filter medium in the first embodiment.
  • the air filter medium 1 has a base material 2 and a fine fiber layer 4 composed of fine fibers 3.
  • the first feature of the air filter medium 1 in the present embodiment is that the fine fiber layer 4 is a multilayer structure composed of a plurality of fine fiber aggregates 5 as shown in FIG.
  • the charge is distributed over 90% of the entire area in the plane direction.
  • the first fine fiber assembly 6 which is a fiber assembly having a lot of positive charges and the second fiber assembly having a lot of negative charges.
  • the fine fiber aggregates 7 are alternately laminated. Thereby, as shown in FIG. 3, polarization can be formed in the lamination direction in the fine fiber layer 4.
  • the fine fiber aggregate 5 refers to both the first fine fiber aggregate 6 and the second fine fiber aggregate 7.
  • the second feature of the air filter medium 1 in the present embodiment is that the material of the fibers forming the fine fibers 3 satisfies the conditions that the volume resistivity is 10 ⁇ 16 ⁇ cm or more and the dielectric loss tangent is 0.001 or less.
  • the polymer was used. Note that “ ⁇ ” is an operator representing a power. The above represents 10 to the 16th power.
  • the volume resistivity of the fibers forming the fine fibers 3 is determined by measuring in accordance with ASTM D257 (standard established by the American Test Materials Association) and the dielectric loss tangent is measured in accordance with ASTM D150 (standards established by the American Test Materials Association). It is done.
  • the volume resistivity is lower than 10 ⁇ 16 ⁇ cm, the fiber is not sufficiently charged, and the dust particle collection efficiency is lowered.
  • the dielectric loss tangent is greater than 0.001, the stability of the charge is deteriorated, and when exposed to water vapor, the charge disappears and the dust particle collection efficiency is lowered.
  • the volume resistivity is more preferably 10 ⁇ 16 ⁇ cm to 10 ⁇ 18 ⁇ cm.
  • polystyrene examples include polypropylene (PP), polyethylene (PE), polycarbonate (PC, PolyCarbonate), polystyrene (PS, Polystyrene), polyphenyl ether (PPE, PolyPhenylEther), polyphenylene oxide (PPO).
  • PP polypropylene
  • PE polyethylene
  • PC polycarbonate
  • PS polystyrene
  • PS polystyrene
  • PPE Polyphenyl ether
  • PPO polyphenylene oxide
  • PolyPhenyleneOxide Polyphenylsulfone (PPSU, PolyPhenylSulfone), Polytetrafluoroethylene (PTFE, PolyTetraFluoroEthylene), Perfluoroalkoxyalkane (PFA, PerFluoro Alkoxyl Alkylene Fluoroethylene-Alkane Fluoroethylene-Polyethylene Alkane Tetraethylene) (ETFE, Ethylene-TetraFluoroEthylenecopolymer), perfluoro ethylene - poly pen copolymer (FEP, PerfluoroEthylenepolypencopolymer), ethylene - chlorotrifluoroethylene copolymer (ECTFE, Ethylene-ChloroTriFluoroEthylenecopolymer) or the like can be used or mixtures thereof.
  • ECTFE Ethylene-ChloroTriFluoroEthylenecopolymer
  • the production method of the fine fiber 3 constituting the fine fiber layer 4 using these polymers is not particularly limited as long as it is a spinning method of a fiber having a nano-order fiber diameter, but an electrostatic spinning method is preferable.
  • the electrospinning method a high voltage is applied to the tip of the nozzle containing the polymer solution, and the polymer solution is sprayed onto the substrate surface charged to the ground or minus, causing the polymer to become fine fibers in the process of scattering the polymer solution.
  • this method includes a process of applying a high voltage, the fine fiber 3 can be charged without separately performing a charging process by using a polymer that satisfies the above-described conditions.
  • the above-mentioned conditions are conditions in which the volume resistivity is 10 ⁇ 16 ⁇ cm or more and the dielectric loss tangent is 0.001 or less.
  • the nonwoven fabric can be damaged by charging and the fine fiber 3 can be charged without lowering the collection efficiency due to leakage, the collection efficiency can be improved.
  • one fiber and one fiber can be charged, it is possible to increase the amount of electric charge of the fiber and improve the dust collecting performance as compared with separately performing the charging process.
  • FIG. 4 is a diagram showing a method for manufacturing the air filter medium in the first embodiment.
  • the manufacturing facility includes a transport unit 8 that transports the substrate 2 in the horizontal direction and a nozzle 9 that is positioned above the transport unit 8.
  • the nozzle 9 sprays a polymer solution in order to form the fine fiber layer 4 on the surface which is the upper surface of the flat substrate 2 conveyed by the conveying unit 8.
  • the conveying unit 8 In the manufacture of the air filter medium 1, first, while the flat substrate 2 is conveyed by the conveying unit 8, a polymer solution is discharged toward the substrate 2 in order to form the fine fiber layer 4 from the nozzle 9. .
  • a voltage of about +20 KV is applied to the nozzle, and the transport unit 8 is grounded.
  • a high polymer solution is drawn from the nozzle 9 to the base material 2 and the fine fibers 3 to be formed are deposited on the surface of the base material 2 to obtain the fine fiber layer 4.
  • the conveyance part 8 is not specified, it may be a conveyor that can convey fibers.
  • the solvent for dissolving the polymer is not particularly limited as long as it is compatible with the polymer and can be dissolved.
  • the solvent include water, alcohols, organic solvents and the like. Specific alcohols and organic solvents include acetone (acetone), chloroform (chloroform), ethanol (ethanol), isopropanol (isopropanol), methanol.
  • the solvent used is a highly polar solvent, and the charging of the polymer can be promoted by a charging method different from the voltage application from the nozzle. Details will be described later.
  • a solvent can be roughly classified into protic (which can supply hydrogen ions) or aprotic.
  • the approximate polarity can be classified depending on whether a hydrogen bond can be formed with other substances.
  • the highly polar solvent used in the present invention is an aprotic solvent capable of forming a protic or hydrogen bond.
  • solvents include acetone, ethanol, isopropanol, methanol, benzyl alcohol, propanol, phenol, pyridine, acetic acid, formic acid, N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), 1,1 , 1,3,3,3-hexafluoro-2-propanol (HFIP), trifluoroacetic acid (TFA), acetonitrile, diethyl ether, or the like, or mixtures thereof.
  • DMF N-dimethylformamide
  • DMAc N, N-dimethylacetamide
  • HFIP 1,1 , 1,3,3,3-hexafluoro-2-propanol
  • TFA trifluoroacetic acid
  • acetonitrile diethyl ether, or the like, or mixtures thereof.
  • the process of charging the polymer includes a process of charging by a voltage applied to the nozzle and a process of charging when the solvent is vaporized.
  • the sign of the charge obtained by the process of charging upon vaporization of the solvent is determined by the combination of the polymer and solvent used.
  • a method for confirming the obtained charge a method using a charged toner shown in [Example] described later is used.
  • the method for forming the first fine fiber aggregate 6 and the second fine fiber aggregate 7 differs depending on the solvent used.
  • a solvent to be used there are a nonpolar solvent and a polar solvent.
  • the applied voltage to the nozzle 9 is used as a pulse power source, and the applied voltage to the nozzle 9 is changed depending on time to form the fine fiber aggregate 5.
  • the first fine fiber assembly 6 is formed, and when a negative voltage is applied to the nozzle 9, the second fine fiber assembly 7 is formed.
  • a polar solvent When a polar solvent is used, it is further divided into two cases. The first is a case where both the process of charging by the voltage applied to the nozzle 9 and the process of charging when the polar solvent is vaporized have the same charge (both processes are charged positively or negatively charged). The second is a case where the process of charging by the voltage applied to the nozzle 9 and the process of charging when the polar solvent is vaporized are opposite charges (the charges charged in both processes are different). In this embodiment, the case of the same charge is described, and the case of the reverse charge is described in Embodiment 2.
  • FIG. 5 is a diagram showing a multilayer manufacturing method of the air filter medium in the first embodiment.
  • a plurality of nozzles 9 are provided in a line along the transport direction of the transport unit 8, and the first nozzle array 10, the second nozzle array 11, and the third nozzle array 12 are sequentially arranged from the transport direction.
  • both the process of charging by the voltage applied to the nozzle 9 and the process of charging when the polar solvent is vaporized have the same charge. Therefore, the first fine fiber aggregate 6 and the second fine fiber aggregate 7 can be forcibly created separately by changing the polarity of the voltage applied to the nozzle 9 in the odd and even rows.
  • the applied voltage of the nozzle 9 is performed from positive, but may be started from negative.
  • the manufactured air filter medium 1 can form a fine fiber layer 4 having a multilayer structure in which fine fiber aggregates 5 whose electric charges are biased in the local lamination direction are alternately laminated.
  • polarization can be formed in the lamination direction in the fine fiber layer 4, an electric field having high strength can be formed in the lamination direction.
  • the first fine fiber aggregate 6 is charged to a positive pole (charge so that the positive charge increases), and the second fine fiber aggregate 7 is charged to a negative polarity (negative It is charged to increase the charge).
  • the nonpolar dust particles are dielectrically polarized, and a negative polarity is generated on the first fine fiber assembly 6 side and a positive polarity is biased on the second fine fiber assembly 7 side.
  • the dust particle end portion side biased to the positive polarity is attracted to the second fine fiber aggregate 7 by electrostatic force and collected. Since the second fine fiber aggregate 7 is configured by entangled and piled up the fine fibers 3, the probability that the dielectrically polarized dust particles are adsorbed is improved, and the collection efficiency is increased.
  • the fine fibers 3 can collect the dust particles. That is, dust particles having negative polarity can be collected by the first fine fiber assembly 6, and dust particles having positive polarity can be collected by the second fine fiber assembly 7. , The collection efficiency can be remarkably improved.
  • the direction of the electrostatic force received from the electric field is reversed depending on the polarity of the charged electric charge of the dust particles, resulting in a difference in the speed of passing through the pores.
  • dust particles having a positive charge are accelerated, but dust particles having a negative charge are decelerated.
  • dust particles having different polarities collide with each other and agglomerate to increase the particle diameter, thereby improving the collection efficiency of the dust particles.
  • the base material 2 that forms the air filter medium 1 is a member that serves as a support for supporting the fine fiber layer 4.
  • the substrate 2 includes pulp fibers, resin fibers, carbon fibers and inorganic fibers, or at least one of them manufactured by a spunbond method, a dry or wet method, a melt blown method, a spunbond method, an airlaid method, or the like. Constructed from non-woven fabric.
  • the average diameter of the fibers constituting the substrate 2 is preferably about 1 ⁇ m to 30 ⁇ m.
  • the average fiber diameter is smaller than 1 ⁇ m, the strength is weak, and when it is larger than 30 ⁇ m, the space between the fibers increases, and the fine fibers 3 forming the fine fiber layer 4 penetrate deep into the base material 2 to increase the pressure loss. is there.
  • the material, shape and length of the substrate are not particularly limited, but if the stiffness of the nonwoven fabric is too low, the pleating process becomes difficult and the productivity is lowered.
  • glass fiber or cellulose fiber is preferable.
  • the fine fiber aggregate 5 is composed of three or more layers.
  • the inner layer 15 sandwiched between the uppermost layer 13 and the lowermost layer 14 has a higher electric field strength because it is sandwiched between charges opposite to the stacking direction. Therefore, dust collection efficiency increases.
  • the electrostatic force from the inside acts on the outer layer, so that the fine fiber 3 is not easily affected by the neutralization of electric charge and has a high collection efficiency. You can maintain the period.
  • the filter medium having a plurality of electric fields in the laminating direction can be constituted by laminating two or more kinds of non-woven fabrics having different polarities on the front surface and the back surface.
  • the pressure loss of the filter medium is high because an adhesive or heat bonding is required.
  • the air filter medium 1 of the present invention a plurality of first fine fiber aggregates 6 and second fine fiber aggregates 7 having different polarities are alternately laminated in the fine fiber layer 4. According to this configuration, it is not necessary to laminate a charged non-woven fabric by adhesion, and deterioration of air permeability due to blockage of pores can be suppressed, so that pressure loss can be reduced.
  • the charge is surrounded in the plane direction and the stacking direction (a local bias of a certain charge is surrounded by the reverse charge). It is characterized in that That is, it has a configuration in which either one of the positive and negative charges is increased and the larger charge is surrounded by the smaller charge.
  • FIG. 6 is a diagram of the manufacturing process of the air filter medium according to the second embodiment as viewed from A of FIG. More specifically, description will be made with reference to Fig. 6 [the conveyance direction in Fig. 4 and a diagram viewed from A (the first nozzle row 10 viewed from the upstream side of the conveyor)]. Since the center fiber 19 spun immediately below the nozzle 9 where the distance between the nozzle 9 to which the high voltage is applied and the base material 2 is close is charged by the electric field between the nozzle 9 and the base material 2, On the other hand, the end fibers 16 that are spun to the outer peripheral portion concentrically extending from directly below the nozzle 9 are not easily affected by the electric field created by the nozzle 9 and the base material 2, and vaporize the polar solvent.
  • opposite charges can be imparted at the location of the center fiber 19 where the distance between the nozzle 9 and the substrate 2 is short and the location of the end fiber 16.
  • it is positive and negative.
  • Charged polymers must have a dielectric loss tangent of 0.001 or less Therefore, once held, the charges are maintained without being released and recombined, and therefore, by providing the gap between the nozzles 9 so that the end fibers 16 overlap, the conveying direction on one layer as shown in FIG. It is possible to form a region in which only the end fibers 16 that are spun to the outer peripheral portion exist, and by changing the arrangement of the nozzles 9, the first fine fiber aggregate 6 and the second fine fiber aggregate 7.
  • a charged layer having the same polarity as the polarity of the nozzle 9 is formed in the stacking direction. It can be formed to surround the charged portion upon evaporation of the polar solvent.
  • FIG. 7 is a view of the manufacturing process of the air filter medium according to the second embodiment as viewed from FIG. 5B.
  • the nozzle 9 of the lower first nozzle array 10 and the nozzle 9 of the upper second nozzle array 11 Arrange the positions of.
  • the nozzles 9 of the second nozzle row 11 are arranged at the center position between the nozzles 9 of the first nozzle row 10.
  • the diameter of the center fiber 19 is the diameter ⁇ of the center fiber and the distance between the center fibers 19 is the distance ⁇ between the center fibers, the diameter of the center fiber ⁇ ⁇ the distance ⁇ between the center fibers, The charge of the end fibers 16 is surrounded by the charge of the center fibers 19 in the second nozzle array 11 in the nozzle array 10.
  • a charge bias can be formed in a band shape by a single nozzle row in the plane direction, and a state of being sandwiched by reverse charges due to the arrangement of the upper and lower nozzle rows in the stacking direction.
  • a local bias of a certain charge is surrounded by the opposite charge even in the plane direction of the produced fine fiber assembly 5.
  • FIG. 8 is a view of the spinning trajectory at the first nozzle row of the air filter medium according to the second embodiment as viewed from B.
  • the center fiber 19 is formed of the center fiber that is meandered by the movement of the first nozzle row 10 and the transport of the base material 2.
  • the first charge concentration portion 17 also meanders along the track 20 of the center fiber.
  • the end fiber 16 is spun into a second charge concentration portion 18 where the center fiber track 20 does not overlap between the nozzles 9 in the first nozzle row 10.
  • the second charge concentration portion 18 can be surrounded by the first charge concentration portion 17 by adjusting the diameter ⁇ of the center fiber and the distance ⁇ between the center fibers. Further, as shown in FIG.
  • the arrangement of the nozzles 9 is different between the first nozzle row 10 and the second nozzle row 11, and the first charge concentration portion 17 can be spun on the upper layer of the second charge concentration portion 18. it can. Accordingly, the second charge concentration portion 18 can be three-dimensionally surrounded by the first charge concentration portion 17 by spinning into a multilayer structure composed of a plurality of fine fiber assemblies 5.
  • the uppermost layer 13 and the lowermost layer 14 are the second fine fiber aggregate 7, and the inner layer 15 is the first fine fiber aggregate.
  • This is a fiber assembly 6.
  • FIG. 6 a state in which the second charge concentration portion 18 is surrounded by the first charge concentration portion 17 also in the planar direction of the first fine fiber aggregate 6 is realized. That is, the negative charge is three-dimensionally surrounded by the positive charge.
  • a state in which positive charges are included in negative charges may be realized. This can be produced by adjusting the spinning amount of the center fiber 19 and the end fiber 16 per unit time, the center fiber diameter ⁇ and the distance ⁇ between the center fibers, the moving speed of the nozzle 9, the transport speed of the substrate 2, and the like. It is.
  • the local charge is strengthened, so that a strong electric field is generated in both the planar direction and the stacking direction. Can be formed. That is, the particle collecting performance of the air filter medium 1 can be remarkably improved by improving the dielectric polarization effect of the passing dust particles and the Coulomb force of the fine fiber layer. Further, it becomes difficult to release charges included in the plane direction, and the charged state can be maintained for a long time.
  • the collection efficiency of dust particles can be increased, the discharge of charge from the atmosphere and the end face of the fine fiber layer 4 is reduced, and the charged state of the fine fiber layer can be maintained for a longer time.
  • the air filter medium 1 is preferably composed of fibers having an average fiber diameter of the fine fibers 3 of 100 to 2000 nm. If the fiber diameter is smaller than 100 nm, the self-supporting property is weak and it is easy to break. On the other hand, when the fiber diameter is larger than 2000 nm, the pores of the three-dimensional network structure formed by the fine fibers 3 are increased, and the Coulomb force that attracts dust in the atmosphere is weakened. Absent. More preferably, the average fiber diameter of the fine fibers 3 is 500 nm to 1500 nm.
  • the pores can be made smaller, so that the collection efficiency by mechanical collection such as blocking or diffusion can be improved. Furthermore, since the distance between the fine fibers 3 is shortened, the electric field strength is increased, and the collection efficiency by electrostatic force can be improved. As a result, the collection efficiency can be further improved. Moreover, since the change of the air flow in the fine fiber 3 vicinity can be made small by making a fiber diameter thin, a turbulent flow can be suppressed and a pressure loss can be reduced.
  • the curvature is increased, the charge density on the surface of the fine fiber 3 is increased, and the electrostatic force is increased, so that dust particles in the vicinity of the fine fiber 3 are easily sucked.
  • the dust particle collection efficiency of the air filter medium 1 can be improved.
  • the fiber diameter here is almost a normal distribution, and the numerical value of the fiber diameter is a numerical value of the center diameter including the variation of the standard deviation.
  • the surface of the obtained filter medium was photographed with a scanning electron microscope (magnification 10,000 times), 20 fiber diameters were measured from the image, and an average value was calculated.
  • the collection efficiency of dust particles is the number of particles with a particle diameter of 0.3 to 0.5 ⁇ m in the air dust upstream and downstream of the filter medium where the filter medium is placed in the duct and the air velocity at the passage surface of the filter medium is 6.5 cm / sec. Measurement was performed three times per sample with a particle counter (manufactured by Kanomax Co., Model 3887), and calculation was performed from the ratio of the number of particles on the upstream side and downstream side. In parallel with the evaluation of the collection efficiency, the pressure loss was obtained by reading the difference in static pressure upstream and downstream of the filter medium with a differential pressure gauge.
  • QF value was calculated from the following calculation formula from the measured collection efficiency and pressure loss. The larger the QF value, the higher the performance as an air filter medium.
  • Example 1 A filter medium was produced by the manufacturing method shown in the first embodiment. Fine fiber 3 is used as base material 2 by using a polyethylene terephthalate (PET) non-woven fabric having a weight per unit area of 98 g / m 2 and a polymer solution of 24% by weight of polystyrene dissolved in N, N-dimethylacetamide. A filter medium on which the fine fiber layer 4 was formed was obtained by spinning. Thereafter, the fiber diameter, the collection efficiency of the filter medium, and the state of charge distribution were evaluated. FIG. 9 is a diagram showing the results of evaluating the fiber diameter, the collection efficiency of the filter medium, and the state of charge distribution in the examples.
  • PET polyethylene terephthalate
  • Example 1 A 25 wt% polymer solution in which polyethersulfone was dissolved in N, N-dimethylacetamide was spun in the same manner as in Example 1 to obtain a filter medium. Thereafter, the fiber diameter, the collection efficiency of the filter medium, and the state of charge distribution were evaluated. The evaluation results are shown in FIG.
  • Comparative Example 2 A 20 wt% polymer solution in which polyvinylidene fluoride was dissolved in N, N-dimethylacetamide was spun in the same manner as in Example 1 to obtain a filter medium. Thereafter, the fiber diameter, the collection efficiency of the filter medium, and the state of charge distribution were evaluated. The evaluation results are shown in FIG.
  • Example 1 In Example 1 using polystyrene having a volume resistance of 10 ⁇ 16 ⁇ cm or more and a dielectric loss tangent of 0.001 or less, a charge distribution in which the aggregates are alternately stacked was confirmed, and a high QF value was exhibited.
  • the charged toner does not adhere and the QF value is low.
  • the air filter medium of the present invention significantly improves the collection efficiency, can be maintained for a long time, and has a low pressure loss. Therefore, it is expected to be utilized as an air filter for home use or office use, and an air purifying apparatus equipped with this air filter.

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  • Chemical Kinetics & Catalysis (AREA)
  • Filtering Materials (AREA)
  • Nonwoven Fabrics (AREA)

Abstract

This air filter medium (1) is provided with a base material (2) and a fine fiber layer (4) disposed on the surface of the base material (2), the fine fiber layer (4) being a multilayer structure comprising a plurality of fine fiber aggregates (5). The volume resistivity of polymers forming fine fibers (3) is 10^16Ωcm or above, the loss tangent is 0.001 or below, and each fine fiber aggregate (5) has the charge distributed to 90% or more of the total area in the planar direction. Moreover, the present invention is characterized in that first fine fiber aggregates (6) in which the fine fibers (3) have mostly positive charges and second fine fiber aggregates (7) in which the fine fibers (3) have mostly negative charges are layered on top of each other in a layering direction at local portions, thereby making it possible to markedly increase collection performance.

Description

エアフィルタ濾材Air filter media
　本発明は、エアフィルタ濾材に関する。 The present invention relates to an air filter medium.
　径が細い繊維を用いた不織布を帯電処理することにより、捕集性能を向上させたエアフィルタ濾材が検討されている（例えば、特許文献１参照）。 An air filter medium whose collection performance is improved by charging a non-woven fabric using fibers having a small diameter has been studied (for example, see Patent Document 1).
　図１０は、従来のエアフィルタ濾材の帯電状態における模式図である。不織布に帯電処理を施したエアフィルタ濾材１００は、図１０に示すように、正の電荷と負の電荷を有する繊維がランダムに分散して存在しているものである（例えば、特許文献２参照）。 FIG. 10 is a schematic diagram of a conventional air filter medium in a charged state. As shown in FIG. 10, the air filter medium 100 obtained by subjecting the nonwoven fabric to charging treatment has fibers having positive charges and negative charges dispersed in a random manner (see, for example, Patent Document 2). ).
特開２００８－０００６８２号公報JP 2008-000682 A 特開昭６１－２１１０２７号公報JP-A-61-211027
　上記従来例において、不織布に正負の電荷がランダムに分散して存在しているため、不織布全体の電界強度が弱く、十分な静電気力が粉塵粒子に働かないことにより、捕集性能が低いという課題があった。さらに、不織布に正負の電荷がランダムに分散して存在しているため、粉塵粒子の受ける静電気力の向きが、不織布を通過する場所によって変化するので、より捕集性能が低下するという課題があった。 In the above conventional example, positive and negative charges are randomly dispersed in the non-woven fabric, so the electric field strength of the entire non-woven fabric is weak, and sufficient electrostatic force does not work on the dust particles, resulting in low collection performance. was there. Furthermore, since positive and negative charges are randomly dispersed in the nonwoven fabric, the direction of electrostatic force received by the dust particles varies depending on the location through which the nonwoven fabric passes. It was.
　そこで、本発明は、不織布に方向性のある電界を設け、粉塵粒子に十分な静電気力を与えることにより、捕集性能を高めたエアフィルタ濾材を提供することを目的とするものである。 Therefore, an object of the present invention is to provide an air filter medium with improved collection performance by providing a directional electric field on a nonwoven fabric and applying sufficient electrostatic force to dust particles.
　そして、この目的を達成するために、本発明の一態様に係るエアフィルタ濾材は、基材と、基材の表面上に設けた細繊維層とを備え、細繊維層は、複数の細繊維集合体からなる多層構造体である。また、細繊維を形成するポリマーの体積抵抗率が１０＾１６Ωｃｍ以上且つ、誘電正接が０．００１以下であり、各細繊維集合体が平面方向には全体面積の９０％以上に帯電が分布している。さらに、局所的な部分での細繊維が積層方向には、正の電荷を多く帯びた第１の細繊維集合体と、負の電荷を多く帯びた第２の細繊維集合体とが、積層されていることを特徴とする。これにより、所期の目的を達成するものである。 In order to achieve this object, an air filter medium according to one embodiment of the present invention includes a base material and a fine fiber layer provided on the surface of the base material, and the fine fiber layer includes a plurality of fine fibers. It is a multilayer structure composed of aggregates. In addition, the volume resistivity of the polymer forming the fine fibers is 10 ^ 16 Ωcm or more and the dielectric loss tangent is 0.001 or less, and the charge is distributed to 90% or more of the entire area in the plane direction of each fine fiber aggregate. ing. Furthermore, in the laminating direction, the fine fibers in the local portion are laminated in the laminating direction with the first fine fiber aggregate having a lot of positive charges and the second fine fiber aggregate having a lot of negative charges. It is characterized by being. This achieves the intended purpose.
　すなわち、本発明によれば、正負の電荷を帯びた細繊維の集合体が積層することで、積層方向に方向性のある高い電界強度を有することができる。これにより、エアフィルタ濾材を通過する粉塵粒子に一方向の十分な静電気力を与えることができるので、繊維が粉塵粒子を強く引きよせることができ、捕集効率を著しく向上することができる。 That is, according to the present invention, a collection of fine fibers having positive and negative charges is laminated, so that a high electric field strength having directionality in the lamination direction can be obtained. Thereby, since sufficient electrostatic force of one direction can be given to the dust particle which passes an air filter medium, a fiber can attract a dust particle strongly and can improve a collection efficiency remarkably.
図１は、実施の形態１におけるエアフィルタ濾材の概略断面図である。1 is a schematic cross-sectional view of an air filter medium according to Embodiment 1. FIG. 図２は、実施の形態１におけるエアフィルタ濾材の細繊維の帯電状態における模式図である。FIG. 2 is a schematic diagram in a charged state of fine fibers of the air filter medium in the first embodiment. 図３は、実施の形態１におけるエアフィルタ濾材の帯電状態における模式図である。FIG. 3 is a schematic diagram in the charged state of the air filter medium in the first embodiment. 図４は、実施の形態１におけるエアフィルタ濾材の製造方法を示す図である。FIG. 4 is a diagram showing a method for manufacturing the air filter medium in the first embodiment. 図５は、実施の形態１におけるエアフィルタ濾材の多層製造方法を示す図である。FIG. 5 is a diagram illustrating a multilayer manufacturing method for an air filter medium in the first embodiment. 図６は、実施の形態２におけるエアフィルタ濾材の製造過程を図４のＡから見た図である。FIG. 6 is a view of the manufacturing process of the air filter medium according to the second embodiment as viewed from A of FIG. 図７は、実施の形態２におけるエアフィルタ濾材の製造過程を図５のＢから見た図である。FIG. 7 is a view of the manufacturing process of the air filter medium according to the second embodiment as viewed from B of FIG. 図８は、実施の形態２におけるエアフィルタ濾材の第一のノズル列での紡糸軌道を図５のＢから見た図である。FIG. 8 is a view of the spinning trajectory in the first nozzle row of the air filter medium according to the second embodiment as viewed from B in FIG. 5. 図９は、実施例における繊維径と濾材の捕集効率、及び、帯電分布の状態を評価した結果を示す図である。FIG. 9 is a diagram showing the results of evaluating the fiber diameter, the filter medium collection efficiency, and the state of charge distribution in the examples. 図１０は、従来のエアフィルタ濾材の帯電状態における模式図である。FIG. 10 is a schematic view of a conventional air filter medium in a charged state.
　本発明の実施の形態に係るエアフィルタ濾材は、基材と、基材の表面上に設けた細繊維層とを備え、細繊維層は、複数の細繊維集合体からなる多層構造体である。細繊維を形成するポリマーの体積抵抗率が１０＾１６Ωｃｍ以上且つ、誘電正接が０．００１以下であり、各細繊維集合体が平面方向には全体面積の９０％以上に帯電が分布している。さらに、局所的な部分での積層方向には、正の電荷を多く帯びた第１の細繊維集合体と、負の電荷を多く帯びた第２の細繊維集合体とが、積層されていることを特徴とする。 An air filter medium according to an embodiment of the present invention includes a base material and a fine fiber layer provided on the surface of the base material, and the fine fiber layer is a multilayer structure including a plurality of fine fiber aggregates. . The volume resistivity of the polymer forming the fine fiber is 10 ^ 16 Ωcm or more and the dielectric loss tangent is 0.001 or less, and the charge distribution is distributed over 90% of the entire area of each fine fiber aggregate in the plane direction. . Furthermore, in the laminating direction in the local portion, the first fine fiber aggregate having a lot of positive charges and the second fine fiber aggregate having a lot of negative charges are laminated. It is characterized by that.
　これにより、細繊維層の積層方向に対して高い電界強度を有することができるので、濾材を通過する粉塵粒子に一方向の十分な静電気力を与えることができる。その結果、細繊維が粉塵粒子を強く引きよせ、吸着することができるので、捕集効率を著しく向上することができる。 This makes it possible to have a high electric field strength with respect to the lamination direction of the fine fiber layers, so that a sufficient electrostatic force in one direction can be given to the dust particles passing through the filter medium. As a result, the fine fibers can attract and adsorb the dust particles strongly, so that the collection efficiency can be remarkably improved.
　また、本発明の実施の形態に係るエアフィルタ濾材は、第１の細繊維集合体と第２の細繊維集合体とが交互に３層以上に積層されていることを特徴とする。 Further, the air filter medium according to the embodiment of the present invention is characterized in that the first fine fiber aggregates and the second fine fiber aggregates are alternately laminated in three or more layers.
　これにより、エアフィルタ濾材の積層方向に対して、最上面と最下面に挟まれた細繊維層はさらに高い電界強度を有することができるので、細繊維が粉塵粒子を強く引きよせ、吸着することができ、捕集効率を著しく向上することができる。 Thereby, since the fine fiber layer sandwiched between the uppermost surface and the lowermost surface can have higher electric field strength with respect to the laminating direction of the air filter medium, the fine fibers strongly attract and adsorb dust particles. And the collection efficiency can be remarkably improved.
　また、本発明の実施の形態に係るエアフィルタ濾材は、繊維層集合体の内部において、平面方向かつ積層方向において、電荷の局所的な偏りが逆電荷によって包囲された状態であることを特徴とする。 Further, the air filter medium according to the embodiment of the present invention is characterized in that the local bias of the charge is surrounded by the reverse charge in the planar direction and the stacking direction inside the fiber layer assembly. To do.
　これにより、局所的な電荷を強めることとなるので、平面方向に対しても積層方向に対しても強い電界を形成でき、粉塵粒子の捕集効率を上げることができる。さらに、大気や細繊維層の端面への接触や導伝が無いので帯電放出が低減され、細繊維層の帯電状態をさらに長時間保持できるようになる。 This enhances the local charge, so that a strong electric field can be formed in both the plane direction and the stacking direction, and the dust particle collection efficiency can be increased. Further, since there is no contact or conduction with the atmosphere or the end face of the fine fiber layer, the charge emission is reduced, and the charged state of the fine fiber layer can be maintained for a longer time.
　また、本発明の実施の形態に係るエアフィルタ濾材は、上記細繊維がポリスチレンからなることを特徴とする。 The air filter medium according to the embodiment of the present invention is characterized in that the fine fibers are made of polystyrene.
　これにより、繊維層に帯電した電荷状態を長時間保持することができる。 Thereby, the charged state of the fiber layer can be maintained for a long time.
　また、本発明の実施の形態に係るエアフィルタ濾材は、細繊維層の平均繊維径が１００ｎｍ～２０００ｎｍの繊維から構成されていてよい。 Further, the air filter medium according to the embodiment of the present invention may be composed of fibers having an average fiber diameter of the fine fiber layer of 100 nm to 2000 nm.
　これにより、繊維径が細くなることで、繊維近傍で生じる乱流を抑制できるので、圧力損失を低減することができる。また、繊維径が細いほど通風時に空気が繊維に衝突する抵抗は少ないため、同じ圧力損失時の空間における繊維量を多くできる。つまり、繊維径が細いほど多くの繊維を使用できる。このため、細孔はより緻密にでき、機械的捕集による粉塵粒子の捕集効率を向上することができる。さらに、繊維間の電界強度が強くなるので、静電気力による粉塵粒子の捕集効率を向上することができる。その結果、より捕集効率を向上することができる。 This makes it possible to suppress the turbulent flow that occurs in the vicinity of the fiber by reducing the fiber diameter, thereby reducing the pressure loss. In addition, the smaller the fiber diameter, the less resistance the air collides with the fiber during ventilation, so the amount of fiber in the space at the same pressure loss can be increased. That is, as the fiber diameter is thinner, more fibers can be used. For this reason, the pores can be made denser, and the dust particle collection efficiency by mechanical collection can be improved. Furthermore, since the electric field strength between fibers becomes strong, the collection efficiency of dust particles by electrostatic force can be improved. As a result, the collection efficiency can be further improved.
　以下、本発明における実施の形態について図面を参照しながら説明するが、本発明は、本実施の形態に限定されるものではない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments.
　（実施の形態１）
　図１は、実施の形態１におけるエアフィルタ濾材の概略断面図である。図２、図３は、実施の形態１におけるエアフィルタ濾材の細繊維の帯電状態における模式図である。図１に示すように、エアフィルタ濾材１は、基材２と細繊維３からなる細繊維層４とを有する。 (Embodiment 1)
1 is a schematic cross-sectional view of an air filter medium according to Embodiment 1. FIG. FIG. 2 and FIG. 3 are schematic diagrams in a charged state of fine fibers of the air filter medium in the first embodiment. As shown in FIG. 1, the air filter medium 1 has a base material 2 and a fine fiber layer 4 composed of fine fibers 3.
　本実施の形態におけるエアフィルタ濾材１の第一の特徴は、図２に示すように、細繊維層４が、複数の細繊維集合体５からなる多層構造体としたことである。細繊維集合体５は、平面方向には全体面積の９０％以上に帯電が分布している。そして、局所的な部分での積層方向には、正の電荷を多く帯びた繊維集合体である第１の細繊維集合体６と、負の電荷を多く帯びた繊維集合体である第２の細繊維集合体７とが交互に積層している。これにより、図３に示すように、細繊維層４内の積層方向に分極を形成することができる。なお、細繊維集合体５は、第１の細繊維集合体６と第２の細繊維集合体７の両方をさす。 The first feature of the air filter medium 1 in the present embodiment is that the fine fiber layer 4 is a multilayer structure composed of a plurality of fine fiber aggregates 5 as shown in FIG. In the fine fiber assembly 5, the charge is distributed over 90% of the entire area in the plane direction. Then, in the stacking direction in the local portion, the first fine fiber assembly 6 which is a fiber assembly having a lot of positive charges and the second fiber assembly having a lot of negative charges. The fine fiber aggregates 7 are alternately laminated. Thereby, as shown in FIG. 3, polarization can be formed in the lamination direction in the fine fiber layer 4. The fine fiber aggregate 5 refers to both the first fine fiber aggregate 6 and the second fine fiber aggregate 7.
　本実施の形態におけるエアフィルタ濾材１の第二の特徴は、細繊維３を形成する繊維の材質を、体積抵抗率が１０＾１６Ωｃｍ以上、且つ、誘電正接が０．００１以下の条件を満たしたポリマーを用いたことである。なお、「＾」は、べき乗を表す演算子である。上記では１０の１６乗を表している。また、細繊維３を形成する繊維の体積抵抗率はＡＳＴＭ　Ｄ２５７（米国試験材料協会策定の規格）に、誘電正接はＡＳＴＭ　Ｄ１５０（米国試験材料協会策定の規格）に準じて測定することで、求められる。 The second feature of the air filter medium 1 in the present embodiment is that the material of the fibers forming the fine fibers 3 satisfies the conditions that the volume resistivity is 10 ^ 16 Ωcm or more and the dielectric loss tangent is 0.001 or less. The polymer was used. Note that “^” is an operator representing a power. The above represents 10 to the 16th power. Further, the volume resistivity of the fibers forming the fine fibers 3 is determined by measuring in accordance with ASTM D257 (standard established by the American Test Materials Association) and the dielectric loss tangent is measured in accordance with ASTM D150 (standards established by the American Test Materials Association). It is done.
　体積抵抗率が１０＾１６Ωｃｍより低いと、繊維の帯電が不十分となり、粉塵粒子の捕集効率が低くなる。また、誘電正接が０．００１より大きいと、電荷の安定性が悪くなり、水蒸気に曝露すると電荷が消失し、粉塵粒子の捕集効率が低下する。なお体積抵抗率は、より好ましくは１０＾１６Ωｃｍ～１０＾１８Ωｃｍである。これらの特性を満たす材質を用いることにより、繊維に多くの電荷を保持できるので、高い電界強度を有することができ、捕集効率を向上することができる。さらに、電荷を安定に保持できるので、細繊維層４の帯電を長期間に渡って維持できるという効果を奏する。上記特性を満たすポリマーとして、例えば、ポリプロピレン（ＰＰ、ＰｏｌｙＰｒｏｐｙｌｅｎｅ）、ポリエチレン（ＰＥ、ＰｏｌｙＥｔｈｙｌｅｎｅ）、ポリカーボネート（ＰＣ、ＰｏｌｙＣａｒｂｏｎａｔｅ）、ポリスチレン（ＰＳ、ＰｏｌｙＳｔｙｒｅｎｅ）、ポリフェニルエーテル（ＰＰＥ、ＰｏｌｙＰｈｅｎｙｌＥｔｈｅｒ）、ポリフェニレンオキシド（ＰＰＯ、ＰｏｌｙＰｈｅｎｙｌｅｎｅＯｘｉｄｅ）、ポリフェニルスルホン（ＰＰＳＵ、ＰｏｌｙＰｈｅｎｙｌＳＵｌｆｏｎｅ）、ポリテトラフルオロエチレン（ＰＴＦＥ、ＰｏｌｙＴｅｔｒａＦｌｕｏｒｏＥｔｈｙｌｅｎｅ）、パーフルオロアルコキシアルカン（ＰＦＡ、ＰｅｒＦｌｕｏｒｏ　Ａｌｋｏｘｙｌ　Ａｌｋａｎｅ）、エチレン－テトラフルオロエチレンコポリマー（ＥＴＦＥ、Ｅｔｈｙｌｅｎｅ－ＴｅｔｒａＦｌｕｏｒｏＥｔｈｙｌｅｎｅｃｏｐｏｌｙｍｅｒ）、パーフルオロエチレン－ポリペンコポリマー（ＦＥＰ、ＰｅｒｆｌｕｏｒｏＥｔｈｙｌｅｎｅｐｏｌｙｐｅｎｃｏｐｏｌｙｍｅｒ）、エチレン－クロロトリフルオロエチレンコポリマー（ＥＣＴＦＥ、Ｅｔｈｙｌｅｎｅ－ＣｈｌｏｒｏＴｒｉＦｌｕｏｒｏＥｔｈｙｌｅｎｅｃｏｐｏｌｙｍｅｒ）などやそれらの混合物を用いることができる。 When the volume resistivity is lower than 10 ^ 16 Ωcm, the fiber is not sufficiently charged, and the dust particle collection efficiency is lowered. On the other hand, when the dielectric loss tangent is greater than 0.001, the stability of the charge is deteriorated, and when exposed to water vapor, the charge disappears and the dust particle collection efficiency is lowered. The volume resistivity is more preferably 10 ^ 16 Ωcm to 10 ^ 18 Ωcm. By using a material satisfying these characteristics, a large amount of electric charge can be retained in the fiber, so that a high electric field strength can be obtained and the collection efficiency can be improved. Furthermore, since the electric charge can be stably held, there is an effect that the charging of the fine fiber layer 4 can be maintained for a long period of time. Examples of the polymer satisfying the above characteristics include polypropylene (PP), polyethylene (PE), polycarbonate (PC, PolyCarbonate), polystyrene (PS, Polystyrene), polyphenyl ether (PPE, PolyPhenylEther), polyphenylene oxide (PPO). , PolyPhenyleneOxide), Polyphenylsulfone (PPSU, PolyPhenylSulfone), Polytetrafluoroethylene (PTFE, PolyTetraFluoroEthylene), Perfluoroalkoxyalkane (PFA, PerFluoro Alkoxyl Alkylene Fluoroethylene-Alkane Fluoroethylene-Polyethylene Alkane Tetraethylene) (ETFE, Ethylene-TetraFluoroEthylenecopolymer), perfluoro ethylene - poly pen copolymer (FEP, PerfluoroEthylenepolypencopolymer), ethylene - chlorotrifluoroethylene copolymer (ECTFE, Ethylene-ChloroTriFluoroEthylenecopolymer) or the like can be used or mixtures thereof.
　これらのポリマーを用いて細繊維層４を構成する細繊維３の製造方法は、ナノオーダーの繊維径を有する繊維の紡糸方法であれば特に限定されないが、静電紡糸法が好ましい。 The production method of the fine fiber 3 constituting the fine fiber layer 4 using these polymers is not particularly limited as long as it is a spinning method of a fiber having a nano-order fiber diameter, but an electrostatic spinning method is preferable.
　静電紡糸法は、ポリマー溶液の入ったノズル先端に高電圧を印加し、アースやマイナスに帯電した基板表面にポリマー溶液を吹き付け、ポリマー溶液が飛散している過程でポリマーの細繊維化を起こすものである。この手法は高電圧を印加する過程を含んでいるため、前述の条件を満たしたポリマーを用いることで、別途、帯電加工を施すことなく、細繊維３を帯電させることができる。ここでいう前述の条件とは、体積抵抗率が１０＾１６Ωｃｍ以上、且つ、誘電正接が０．００１以下、の条件である。すなわち、帯電加工で不織布を破損させ、リークによる捕集効率の低下を起こすことなく、細繊維３に帯電加工を施すことができるので、捕集効率を向上させることができる。また、繊維の１本、１本を帯電できるため、別途、帯電加工を行うよりも繊維の電荷量を多くすることができ、集塵性能を向上することができる。 In the electrospinning method, a high voltage is applied to the tip of the nozzle containing the polymer solution, and the polymer solution is sprayed onto the substrate surface charged to the ground or minus, causing the polymer to become fine fibers in the process of scattering the polymer solution. Is. Since this method includes a process of applying a high voltage, the fine fiber 3 can be charged without separately performing a charging process by using a polymer that satisfies the above-described conditions. The above-mentioned conditions here are conditions in which the volume resistivity is 10 ^ 16 Ωcm or more and the dielectric loss tangent is 0.001 or less. That is, since the nonwoven fabric can be damaged by charging and the fine fiber 3 can be charged without lowering the collection efficiency due to leakage, the collection efficiency can be improved. In addition, since one fiber and one fiber can be charged, it is possible to increase the amount of electric charge of the fiber and improve the dust collecting performance as compared with separately performing the charging process.
　ここで、エアフィルタ濾材１の製造方法について説明する。図４は、実施の形態１におけるエアフィルタ濾材の製造方法を示す図である。図４に示すように、製造設備は、基材２を載せて水平方向へ搬送する搬送部８と、この搬送部８の上方に位置するノズル９とから構成される。 Here, a method for manufacturing the air filter medium 1 will be described. FIG. 4 is a diagram showing a method for manufacturing the air filter medium in the first embodiment. As shown in FIG. 4, the manufacturing facility includes a transport unit 8 that transports the substrate 2 in the horizontal direction and a nozzle 9 that is positioned above the transport unit 8.
　ノズル９は、搬送部８によって搬送される平板状の基材２の上面である表面上に細繊維層４を形成するために高分子ポリマー溶液を吹き付けるものである。 The nozzle 9 sprays a polymer solution in order to form the fine fiber layer 4 on the surface which is the upper surface of the flat substrate 2 conveyed by the conveying unit 8.
　エアフィルタ濾材１の製造は、まず、平板形状の基材２を搬送部８によって搬送させながら、ノズル９から細繊維層４を形成するために高分子ポリマー溶液を基材２に向かって放出する。ここで、ノズルには、＋２０ＫＶ程度の電圧が印加され、搬送部８はアース処理をされている。この電位差によって、ノズル９から基材２へ高分子ポリマー溶液を曳糸し、形成される細繊維３を基材２の表面に堆積することで、細繊維層４を得る。搬送部８は特定しないが、繊維を搬送できるコンベアのようなもので良い。 In the manufacture of the air filter medium 1, first, while the flat substrate 2 is conveyed by the conveying unit 8, a polymer solution is discharged toward the substrate 2 in order to form the fine fiber layer 4 from the nozzle 9. . Here, a voltage of about +20 KV is applied to the nozzle, and the transport unit 8 is grounded. By this potential difference, a high polymer solution is drawn from the nozzle 9 to the base material 2 and the fine fibers 3 to be formed are deposited on the surface of the base material 2 to obtain the fine fiber layer 4. Although the conveyance part 8 is not specified, it may be a conveyor that can convey fibers.
　高分子ポリマーを溶解させる溶媒としては、高分子ポリマーと相溶性があり、溶解させることが出来れば特に限定されない。溶媒としての一例は、水、アルコール類、有機溶剤等が挙げられ、具体的なアルコール類や有機溶剤としては、アセトン（Ａｃｅｔｏｎｅ）、クロロホルム（Ｃｈｌｏｒｏｆｏｒｍ）、エタノール（Ｅｔｈａｎｏｌ）、イソプロパノール（Ｉｓｏｐｒｏｐａｎｏｌ）、メタノール（Ｍｅｔｈａｎｏｌ）、トルエン（Ｔｏｌｕｅｎｅ）、テトラヒドロフラン（Ｔｅｔｒａｈｙｄｒｏｆｕｒａｎ））、ベンゼン（Ｂｅｎｚｅｎｅ））、ベンジルアルコール（Ｂｅｎｚｙｌ　Ａｌｃｏｈｏｌ）、１，４－ジオキサン（１，４－Ｄｉｏｘａｎｅ）、プロパノール（Ｐｒｏｐａｎｏｌ）、ジクロロメタン（ＤＣＭ、ＤｉＣｈｌｏｒｏＭｅｔｈａｎｅ）、四塩化炭素（Ｃａｒｂｏｎ　Ｔｅｔｒａｃｈｌｏｒｉｄｅ）、シクロヘキサン（Ｃｙｃｌｏｈｅｘａｎｅ）、シクロヘキサノン（Ｃｙｃｌｏｈｅｘａｎｏｎｅ）、塩化メチレン（Ｍｅｔｈｙｌｅｎｅ　Ｃｈｌｏｒｉｄｅ）、フェノール（Ｐｈｅｎｏｌ）、ピリジン（Ｐｙｒｉｄｉｎｅ）、酢酸（Ａｃｅｔｉｃ　Ａｃｉｄ）、蟻酸（Ｆｏｒｍｉｃ　Ａｃｉｄ）、Ｎ，Ｎ－ジメチルホルムアミド（ＤＭＦ、Ｎ，Ｎ－ＤｉＭｅｔｈｙｌＦｏｒｍａｍｉｄｅ）、ジメチルスルホキシド（ＤＭＳＯ、ＤｉＭｅｔｈｙｌ　ＳｕｌｆＯｘｉｄｅ）、Ｎ，Ｎ－ジメチルアセトアミド（ＤＭＡｃ、Ｎ，Ｎ－ＤｉＭｅｔｈｙｌａｃｅｔａｍｉｄｅ）、１－メチル－２－ピロリドン（ＮＭＰ、Ｎ－ＭｅｔｈｙｌＰｙｒｒｏｌｉｄｏｎｅ）、１，１，１，３，３，３－ヘキサフルオロ－２－プロパノール（ＨＦＩＰ、ＨｅｘａＦｌｕｏｒｏＩｓｏｐｒｏｐｙｌ　Ａｌｃｏｈｏｌ）、トリフルオロ酢酸（ＴＦＡ、ＴｒｉＦｌｕｏｒｏａｃｅｔｉｃ　Ａｃｉｄ）、エチレンカーボネート（Ｅｔｈｙｌｅｎｅ　Ｃａｒｂｏｎａｔｅ）、プロピレンカーボネート（Ｐｒｏｐｙｌｅｎｅ　Ｃａｒｂｏｎａｔｅ）、ジメチルカーボネート（Ｄｉｍｅｔｈｙｌ　Ｃａｒｂｏｎａｔｅ）、アセトニトリル（Ａｃｅｔｏｎｉｔｒｉｌｅ）、γ－ブチロラクトン（Ｇａｎｍａ－Ｂｕｔｙｒｏｌａｃｔｏｎｅ）、ジエチルカーボネート（Ｄｉｅｔｈｙｌ　Ｃａｒｂｏｎａｔｅ）、ジエチルエーテル（Ｄｉｅｔｈｙｌ　Ｅｔｈｅｒ）、１，２－ジメトキシエタン（Ｄｉｍｅｔｈｏｘｙｅｔｈａｎｅ）、１，３－ジメチル－２－イミダゾリジノン（１，３－Ｄｉｍｅｔｈｙｌ－２－Ｉｍｉｄａｚｏｌｉｄｉｎｏｎｅ）、１，３－ジオキソラン（１，３－Ｄｉｏｘｏｌａｎ）、エチルメチルカーボネート（Ｅｔｈｙｌ　Ｍｅｔｈｙｌ　Ｃａｒｂｏｎａｔｅ）、２－メチルテトラヒドロフラン（２－Ｍｅｔｈｙｌｔｅｔｒａｈｙｄｒｏｆｕｒａｎ）、スルホラン（Ｓｕｌｆｏｌａｎｅ）など、またはそれらの混合物を用いることができる。また、用いる溶媒が極性の高い溶媒であればなお良く、ノズルからの電圧印加とは別の帯電方法でポリマーの帯電を促せる。詳細については後述する。一般的に、溶媒はプロトン性（水素イオンを供給できる）、もしくは非プロトン性に大別でき、非プロトン性においては、他の物質と水素結合を形成できるかで、おおよその極性が分類できる。本発明で用いる、極性が高い溶媒とはプロトン性もしくは水素結合を形成可能な非プロトン性溶媒である。これらの溶媒としては、アセトン、エタノール、イソプロパノール、メタノール、ベンジルアルコール、プロパノール、フェノール、ピリジン、酢酸、蟻酸、Ｎ，Ｎ－ジメチルホルムアミド（ＤＭＦ）、Ｎ，Ｎ－ジメチルアセトアミド（ＤＭＡｃ）、１，１，１，３，３，３－ヘキサフルオロ－２－プロパノール（ＨＦＩＰ）、トリフルオロ酢酸（ＴＦＡ）、アセトニトリル、ジエチルエーテルなど、またはそれらの混合物を用いることができる。 The solvent for dissolving the polymer is not particularly limited as long as it is compatible with the polymer and can be dissolved. Examples of the solvent include water, alcohols, organic solvents and the like. Specific alcohols and organic solvents include acetone (acetone), chloroform (chloroform), ethanol (ethanol), isopropanol (isopropanol), methanol. (Methanol), toluene (Toluene), tetrahydrofuran (Tetrahydrofuran), benzene (Benzene)), benzyl alcohol (Benzyl Alcohol), 1,4-dioxane (1,4-Dioxane), propanol (Propanol), dichloromethane (DCM, DiChloroMethane), carbon tetrachloride (Carbon Tetrachloride), cyclohexane (Cyclohexa) e), Cyclohexanone, Methylene Chloride, Phenol, Pyridine, Acetic Acid, Formic Acid, N, N-dimethylformamide (DMF, N, N-) DiMethylFormamide), dimethyl sulfoxide (DMSO, DiMethyl SulphOxide), N, N-dimethylacetamide (DMAc, N, N-DiMethylacetamide), 1-methyl-2-pyrrolidone (NMP, N-Methylylpyrrolidone) , 3,3-hexafluoro-2-propanol (HFIP, HexaFluoroisopropyl Alc hol), trifluoroacetic acid (TFA, TriFluoroacetic Acid), ethylene carbonate (Ethylene Carbonate), propylene carbonate (Propylene Carbonate), dimethyl carbonate (Dimethyyl Carbonate), acetonitrile (Acetonitrile), γ-butyrolactone (Ga-N-butyrolactone) (Diethyl Carbonate), Diethyl ether (Diethyl Ether), 1,2-dimethoxyethane, 1,3-dimethyl-2-imidazolidinone (1,3-Dimethyl-2-imidazolidinone), 1,3-dioxolane (1,3-Dioxolan), ethyl methyl carbonate (Ethyl Methyl Carbonate), 2- methyltetrahydrofuran (2-Methyltetrahydrofuran), it can be used sulfolane (Sulfolane), etc., or mixtures thereof. Further, it is better if the solvent used is a highly polar solvent, and the charging of the polymer can be promoted by a charging method different from the voltage application from the nozzle. Details will be described later. In general, a solvent can be roughly classified into protic (which can supply hydrogen ions) or aprotic. In aprotic, the approximate polarity can be classified depending on whether a hydrogen bond can be formed with other substances. The highly polar solvent used in the present invention is an aprotic solvent capable of forming a protic or hydrogen bond. These solvents include acetone, ethanol, isopropanol, methanol, benzyl alcohol, propanol, phenol, pyridine, acetic acid, formic acid, N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), 1,1 , 1,3,3,3-hexafluoro-2-propanol (HFIP), trifluoroacetic acid (TFA), acetonitrile, diethyl ether, or the like, or mixtures thereof.
　上記静電紡糸法においてポリマーが帯電する過程としては、ノズルに印加した電圧により帯電する過程と、溶媒の気化に際して帯電する過程がある。溶媒の気化に際して帯電する過程により得られる電荷の正負は、使用するポリマーと溶媒の組合せで決まる。得られた帯電の確認方法については、後述する〔実施例〕で示す帯電トナーを使用した手法を用いる。 In the electrostatic spinning method, the process of charging the polymer includes a process of charging by a voltage applied to the nozzle and a process of charging when the solvent is vaporized. The sign of the charge obtained by the process of charging upon vaporization of the solvent is determined by the combination of the polymer and solvent used. As a method for confirming the obtained charge, a method using a charged toner shown in [Example] described later is used.
　第１の細繊維集合体６と第２の細繊維集合体７を形成する方法は、使用する溶媒によって異なる。使用する溶媒としては、非極性溶媒と極性溶媒とがある。 The method for forming the first fine fiber aggregate 6 and the second fine fiber aggregate 7 differs depending on the solvent used. As a solvent to be used, there are a nonpolar solvent and a polar solvent.
　非極性溶媒を用いる場合は、ノズル９への印加電圧をパルス電源とし、時間によってノズル９への印加電圧の正負を入れ替えて細繊維集合体５を形成する。正の電圧をノズル９へ印加した場合は第１の細繊維集合体６が形成され、負の電圧をノズル９へ印加した場合には第２の細繊維集合体７が形成される。 When using a non-polar solvent, the applied voltage to the nozzle 9 is used as a pulse power source, and the applied voltage to the nozzle 9 is changed depending on time to form the fine fiber aggregate 5. When a positive voltage is applied to the nozzle 9, the first fine fiber assembly 6 is formed, and when a negative voltage is applied to the nozzle 9, the second fine fiber assembly 7 is formed.
　次に、極性溶媒を用いる場合について説明する。極性溶媒を用いた場合にはさらに２つの場合に分けられる。１つめは、ノズル９に印加した電圧により帯電する過程と極性溶媒の気化に際して帯電する過程とが共に同電荷（両過程とも正電荷に帯電、もしくは負電荷に帯電）の場合である。２つめは、ノズル９に印加した電圧により帯電する過程と、極性溶媒の気化に際して帯電する過程とが逆電荷（両過程で帯電する電荷が異なる）の場合である。本実施の形態では、同電荷となる場合について説明し、逆電荷となる場合については、実施の形態２で説明する。 Next, the case where a polar solvent is used will be described. When a polar solvent is used, it is further divided into two cases. The first is a case where both the process of charging by the voltage applied to the nozzle 9 and the process of charging when the polar solvent is vaporized have the same charge (both processes are charged positively or negatively charged). The second is a case where the process of charging by the voltage applied to the nozzle 9 and the process of charging when the polar solvent is vaporized are opposite charges (the charges charged in both processes are different). In this embodiment, the case of the same charge is described, and the case of the reverse charge is described in Embodiment 2.
　図５は、実施の形態１におけるエアフィルタ濾材の多層製造方法を示す図である。図５に示すように、搬送部８の搬送方向に沿って、ノズル９を列状に複数設け、搬送方向から順に第一のノズル列１０、第二のノズル列１１、第三のノズル列１２とする。この場合、ノズル９に印加した電圧により帯電する過程と、極性溶媒の気化に際して帯電する過程とが共に同電荷となる。そのため、奇数列と偶数列でノズル９への印加電圧の正負を変えることで第１の細繊維集合体６と第２の細繊維集合体７を強制的に作り分けることが可能となる。この製造方法においては、ノズル９の列が多いほど多くの積層構造が形成でき、所定の効果を得ることができる。また、図５ではノズル９の印加電圧を正から行っているが、負から開始しても良い。 FIG. 5 is a diagram showing a multilayer manufacturing method of the air filter medium in the first embodiment. As shown in FIG. 5, a plurality of nozzles 9 are provided in a line along the transport direction of the transport unit 8, and the first nozzle array 10, the second nozzle array 11, and the third nozzle array 12 are sequentially arranged from the transport direction. And In this case, both the process of charging by the voltage applied to the nozzle 9 and the process of charging when the polar solvent is vaporized have the same charge. Therefore, the first fine fiber aggregate 6 and the second fine fiber aggregate 7 can be forcibly created separately by changing the polarity of the voltage applied to the nozzle 9 in the odd and even rows. In this manufacturing method, as the number of nozzles 9 is increased, a larger number of stacked structures can be formed, and a predetermined effect can be obtained. Further, in FIG. 5, the applied voltage of the nozzle 9 is performed from positive, but may be started from negative.
　上記製造方法により、製造されたエアフィルタ濾材１は、局所的な積層方向に電荷の偏った細繊維集合体５を交互に積層した多層構造となる細繊維層４を形成することができる。これにより、図３に示すように、細繊維層４内の積層方向に分極を形成することができるので、積層方向に強度の高い電界を形成することができる。本実施の形態では、第１の細繊維集合体６を正の極に帯電（正の電荷が多くなるように帯電）させ、第２の細繊維集合体７を負の極性に帯電（負の電荷が多くなるように帯電）させている。 By the above manufacturing method, the manufactured air filter medium 1 can form a fine fiber layer 4 having a multilayer structure in which fine fiber aggregates 5 whose electric charges are biased in the local lamination direction are alternately laminated. Thereby, as shown in FIG. 3, since polarization can be formed in the lamination direction in the fine fiber layer 4, an electric field having high strength can be formed in the lamination direction. In the present embodiment, the first fine fiber aggregate 6 is charged to a positive pole (charge so that the positive charge increases), and the second fine fiber aggregate 7 is charged to a negative polarity (negative It is charged to increase the charge).
　したがって、無極性の粉塵粒子は誘電分極され、第１の細繊維集合体６側に負の極性が、第２の細繊維集合体７側に正の極性が偏り生じる。これにより、正の極性に偏りをもった粉塵粒子端部側は第２の細繊維集合体７に静電気力で引寄せられ、捕集される。第２の細繊維集合体７は、細繊維３が絡み合い積み重なって構成されているので、誘電分極された粉塵粒子が吸着する確率が向上し、捕集効率が高くなる。 Therefore, the nonpolar dust particles are dielectrically polarized, and a negative polarity is generated on the first fine fiber assembly 6 side and a positive polarity is biased on the second fine fiber assembly 7 side. As a result, the dust particle end portion side biased to the positive polarity is attracted to the second fine fiber aggregate 7 by electrostatic force and collected. Since the second fine fiber aggregate 7 is configured by entangled and piled up the fine fibers 3, the probability that the dielectrically polarized dust particles are adsorbed is improved, and the collection efficiency is increased.
　さらに、本発明のエアフィルタ濾材１は、極性を有した細繊維集合体５である第１の細繊維集合体６と第２の細繊維集合体７とが交互に積層されているため、電荷を帯びた粉塵粒子は異極性の細繊維３近傍を通過するので、細繊維３は粉塵粒子を捕集することができる。つまり、負の極性を帯びた粉塵粒子を、第１の細繊維集合体６で捕集し、正の極性を帯びた粉塵粒子を第２の細繊維集合体７で捕集することができるので、捕集効率を著しく向上することができる。 Furthermore, in the air filter medium 1 of the present invention, since the first fine fiber aggregates 6 and the second fine fiber aggregates 7 that are polar fine fiber aggregates 5 are alternately laminated, Since the dust particles tinged pass through the vicinity of the fine fibers 3 of different polarity, the fine fibers 3 can collect the dust particles. That is, dust particles having negative polarity can be collected by the first fine fiber assembly 6, and dust particles having positive polarity can be collected by the second fine fiber assembly 7. , The collection efficiency can be remarkably improved.
　そして、第１の細繊維集合体６と第２の細繊維集合体７とを交互に複数配置することで、静電気力により粉塵粒子を捕集する機会を増やすことができるので、より捕集効率を向上することができる。 And since the opportunity which collects dust particles by electrostatic force can be increased by arranging a plurality of first fine fiber aggregates 6 and second fine fiber aggregates 7 alternately, more collection efficiency Can be improved.
　また、粉塵粒子は帯びた電荷の極性により、電界から受ける静電気力の向きが逆になるので、細孔を通過する速度に差が生じる。例えば、第１の細繊維集合体６から第２の細繊維集合体７に向けて通過する際は、正の電荷を帯びた粉塵粒子は加速するが、負の電荷を帯びた粉塵粒子は減速する。これにより、極性の異なる粉塵粒子同士が衝突し、凝集することで、粒子径が増大するため、粉塵粒子の捕集効率が向上する。なお、本実施の形態では、第１の細繊維集合体６と第２の細繊維集合体７を交互に多層に積層した形態を説明しているが、これに限定するものではなく、第１の細繊維集合体６と第２の細繊維集合体７をそれぞれ１層ずつ備えたものであっても良い。 Also, the direction of the electrostatic force received from the electric field is reversed depending on the polarity of the charged electric charge of the dust particles, resulting in a difference in the speed of passing through the pores. For example, when passing from the first fine fiber aggregate 6 toward the second fine fiber aggregate 7, dust particles having a positive charge are accelerated, but dust particles having a negative charge are decelerated. To do. Thereby, dust particles having different polarities collide with each other and agglomerate to increase the particle diameter, thereby improving the collection efficiency of the dust particles. In addition, in this Embodiment, although the form which laminated | stacked the 1st fine fiber assembly 6 and the 2nd fine fiber assembly 7 alternately in the multilayer was demonstrated, it is not limited to this, 1st The fine fiber aggregate 6 and the second fine fiber aggregate 7 may each be provided with one layer.
　なおエアフィルタ濾材１を形成する基材２については、細繊維層４を支持する支持体となる部材である。基材２は、スパンボンド法、乾式または湿式法、メルトブローン法、スパンボンド法、エアレイド法などにより製造されたパルプ繊維、樹脂繊維、炭素繊維および無機繊維、またはそれらの少なくとも１つを含んでいる不織布から構成される。また、基材２を構成する繊維の平均径は、１μｍ～３０μｍ程度が好ましい。平均繊維径が１μｍより小さいと強度が弱く、３０μｍより大きいと繊維同士の空間が大きくなり、細繊維層４を形成する細繊維３が基材２の深くまで入り込み、圧力損失を増大させるためである。基材の材質、形状、長さについては特に限定されないが、不織布の剛性が低すぎるとプリーツ加工が困難になり、生産性が低下するので、プリーツ加工に耐えられる程度の剛性があれば良く、例えばガラス繊維やセルロース繊維などが好ましい。 The base material 2 that forms the air filter medium 1 is a member that serves as a support for supporting the fine fiber layer 4. The substrate 2 includes pulp fibers, resin fibers, carbon fibers and inorganic fibers, or at least one of them manufactured by a spunbond method, a dry or wet method, a melt blown method, a spunbond method, an airlaid method, or the like. Constructed from non-woven fabric. The average diameter of the fibers constituting the substrate 2 is preferably about 1 μm to 30 μm. When the average fiber diameter is smaller than 1 μm, the strength is weak, and when it is larger than 30 μm, the space between the fibers increases, and the fine fibers 3 forming the fine fiber layer 4 penetrate deep into the base material 2 to increase the pressure loss. is there. The material, shape and length of the substrate are not particularly limited, but if the stiffness of the nonwoven fabric is too low, the pleating process becomes difficult and the productivity is lowered. For example, glass fiber or cellulose fiber is preferable.
　以上のように、本実施の形態のエアフィルタ濾材１は、細繊維集合体５が３層以上からなる。最上層１３と最下層１４に挟まれた内部層１５は、積層方向に対して逆の電荷で挟まれた状態になるため、より高い電界強度を有する。したがって、粉塵の集塵効率が増大する。また、大気に露出している外層に粉塵粒子が付着しても、内部からの静電気力が外層に働くため、細繊維３は電荷の中和による減衰効果を受け難く、高い捕集効率を長期間維持できる。 As described above, in the air filter medium 1 of the present embodiment, the fine fiber aggregate 5 is composed of three or more layers. The inner layer 15 sandwiched between the uppermost layer 13 and the lowermost layer 14 has a higher electric field strength because it is sandwiched between charges opposite to the stacking direction. Therefore, dust collection efficiency increases. In addition, even if dust particles adhere to the outer layer exposed to the atmosphere, the electrostatic force from the inside acts on the outer layer, so that the fine fiber 3 is not easily affected by the neutralization of electric charge and has a high collection efficiency. You can maintain the period.
　また、積層方向に複数の電界を有する濾材は、表面と裏面の極性が異なる２種類以上の不織布を積層することにより、構成することができる。この場合、接着材や熱による接着が必要なため、濾材の圧力損失が高くなっていた。それに対し、本発明のエアフィルタ濾材１は、細繊維層４内に、極性の異なる第１の細繊維集合体６と第２の細繊維集合体７を交互に複数積層している。この構成によれば、電荷を帯びた不織布を接着により積層させる必要が無く、細孔の閉塞による通気性の悪化を抑制できるため、圧力損失を低くすることができる。 Moreover, the filter medium having a plurality of electric fields in the laminating direction can be constituted by laminating two or more kinds of non-woven fabrics having different polarities on the front surface and the back surface. In this case, the pressure loss of the filter medium is high because an adhesive or heat bonding is required. On the other hand, in the air filter medium 1 of the present invention, a plurality of first fine fiber aggregates 6 and second fine fiber aggregates 7 having different polarities are alternately laminated in the fine fiber layer 4. According to this configuration, it is not necessary to laminate a charged non-woven fabric by adhesion, and deterioration of air permeability due to blockage of pores can be suppressed, so that pressure loss can be reduced.
　（実施の形態２）
　実施の形態２のエアフィルタ濾材１は、細繊維集合体５の内部層１５において、平面方向かつ積層方向に対して電荷が包囲された状態（ある電荷の局所的な偏りがその逆電荷によって囲まれた状態）であることを特徴とする。すなわち、正負どちらか一方の電荷を多くして、多いほうの電荷で少ないほうの電荷を包囲する構成を備えたものである。 (Embodiment 2)
In the air filter medium 1 according to the second embodiment, in the inner layer 15 of the fine fiber assembly 5, the charge is surrounded in the plane direction and the stacking direction (a local bias of a certain charge is surrounded by the reverse charge). It is characterized in that That is, it has a configuration in which either one of the positive and negative charges is increased and the larger charge is surrounded by the smaller charge.
　このエアフィルタ濾材１の製造に関しては、極性溶媒を使用し、かつノズル９に印加した電圧により帯電する過程と極性溶媒の気化に際して帯電する過程とが逆電荷である場合である。また、さらにノズル９の列を搬送方向に対して垂直方向に可動とした場合に作製が可能となる。 Regarding the production of the air filter medium 1, there is a case where a polar solvent is used and the process of charging by the voltage applied to the nozzle 9 and the process of charging when the polar solvent is vaporized are opposite charges. Further, it is possible to manufacture when the row of nozzles 9 is movable in the direction perpendicular to the transport direction.
　図６は、実施の形態２におけるエアフィルタ濾材の製造過程を図４のＡから見た図である。具体的に、図６〔図４の搬送方向、Ａから見た図（第一のノズル列１０をコンベアの上流側から見た図〕〕を用いて説明する。図６に示すように、紡糸時において高電圧が印加されているノズル９と基材２の距離が近いノズル９の直下へ紡糸される中心繊維１９は、ノズル９と基材２の間の電界により帯電するため、ノズル９の極性と同じ極に帯電する。一方でノズル９の直下から同心円状に広がった外周部へ紡糸される端繊維１６は、ノズル９と基材２の作る電界の影響を受けにくく、極性溶媒の気化に際して帯電する。つまり、ノズル９と基材２の距離が近い中心繊維１９の箇所と、端繊維１６の箇所で逆の電荷を持たせることができる。そして、実施の形態１と同様に正負の電荷を帯びたポリマーは誘電正接を０．００１以下のものを用いることで、一度保持した電荷が放出、再結合せず維持される。そのため、端繊維１６が重なるようにノズル９の間隔を設けることで、図６に示すように一つの層上の搬送方向に外周部へ紡糸される端繊維１６だけが存在する領域を形成することができる。さらに、ノズル９の配置を変えることで、第１の細繊維集合体６と第２の細繊維集合体７の多層構造を形成することができる。特に、搬送方向に見て、中心繊維１９に対して、端繊維１６の幅を少なくすることで、ノズル９の極性と同じ極性の帯電層を積層方向に形成して、極性溶媒の気化に際して帯電した部分を包囲することができる。 FIG. 6 is a diagram of the manufacturing process of the air filter medium according to the second embodiment as viewed from A of FIG. More specifically, description will be made with reference to Fig. 6 [the conveyance direction in Fig. 4 and a diagram viewed from A (the first nozzle row 10 viewed from the upstream side of the conveyor)]. Since the center fiber 19 spun immediately below the nozzle 9 where the distance between the nozzle 9 to which the high voltage is applied and the base material 2 is close is charged by the electric field between the nozzle 9 and the base material 2, On the other hand, the end fibers 16 that are spun to the outer peripheral portion concentrically extending from directly below the nozzle 9 are not easily affected by the electric field created by the nozzle 9 and the base material 2, and vaporize the polar solvent. In other words, opposite charges can be imparted at the location of the center fiber 19 where the distance between the nozzle 9 and the substrate 2 is short and the location of the end fiber 16. As in the first embodiment, it is positive and negative. Charged polymers must have a dielectric loss tangent of 0.001 or less Therefore, once held, the charges are maintained without being released and recombined, and therefore, by providing the gap between the nozzles 9 so that the end fibers 16 overlap, the conveying direction on one layer as shown in FIG. It is possible to form a region in which only the end fibers 16 that are spun to the outer peripheral portion exist, and by changing the arrangement of the nozzles 9, the first fine fiber aggregate 6 and the second fine fiber aggregate 7. In particular, when the width of the end fiber 16 is reduced with respect to the center fiber 19 when viewed in the transport direction, a charged layer having the same polarity as the polarity of the nozzle 9 is formed in the stacking direction. It can be formed to surround the charged portion upon evaporation of the polar solvent.
　図７は、実施の形態２におけるエアフィルタ濾材の製造過程を図５のＢから見た図である。例えば、図７〔図５の基材上方、Ｂ（紡糸上方）から見た図〕に示すように、下層の第一のノズル列１０のノズル９と上層の第二のノズル列１１のノズル９の位置を入れ違いに配置する。本実施の形態では、一例として、第一のノズル列１０のノズル９間の中心位置に第二のノズル列１１のノズル９を配置する。かつ、中心繊維１９の直径を中心繊維の直径α、中心繊維１９間の距離を中心繊維間の距離βとしたときに中心繊維の直径α≧中心繊維間の距離βの場合に、第一のノズル列１０で端繊維１６の電荷が、第二のノズル列１１で中心繊維１９の電荷に包囲される。 FIG. 7 is a view of the manufacturing process of the air filter medium according to the second embodiment as viewed from FIG. 5B. For example, as shown in FIG. 7 [viewed from above the base material in FIG. 5, B (above spinning)], the nozzle 9 of the lower first nozzle array 10 and the nozzle 9 of the upper second nozzle array 11 Arrange the positions of. In the present embodiment, as an example, the nozzles 9 of the second nozzle row 11 are arranged at the center position between the nozzles 9 of the first nozzle row 10. And, when the diameter of the center fiber 19 is the diameter α of the center fiber and the distance between the center fibers 19 is the distance β between the center fibers, the diameter of the center fiber α ≧ the distance β between the center fibers, The charge of the end fibers 16 is surrounded by the charge of the center fibers 19 in the second nozzle array 11 in the nozzle array 10.
　したがって、平面方向には１つのノズル列によって帯状に電荷の偏りが形成でき、積層方向には上層と下層のノズル列の配置よって逆電荷で挟まれた状態になる。 Therefore, a charge bias can be formed in a band shape by a single nozzle row in the plane direction, and a state of being sandwiched by reverse charges due to the arrangement of the upper and lower nozzle rows in the stacking direction.
　さらに、この製造方法において、同一平面上で、ノズル９の列を可動させることで、作製した細繊維集合体５の平面方向においても、ある電荷の局所的な偏りがその逆電荷によって囲まれた状態を作り出すことができる。具体的には、図６に示すように、中心繊維１９による正の電荷の局所的な偏りである第一の電荷集中部１７と、端繊維１６による負の電荷の偏りである第二の電荷集中部１８として作り分けることが可能である。 Furthermore, in this manufacturing method, by moving the row of nozzles 9 on the same plane, a local bias of a certain charge is surrounded by the opposite charge even in the plane direction of the produced fine fiber assembly 5. Can create a state. Specifically, as shown in FIG. 6, a first charge concentration portion 17 that is a local bias of positive charges by the center fiber 19 and a second charge that is a bias of negative charges by the end fibers 16. It is possible to make them separately as the concentration unit 18.
　例えば、図８（ノズル９上方から見た、第一のノズル列１０が平面状に紡糸する際のノズル９と中心繊維の軌道２０）に示す。図８は、実施の形態２におけるエアフィルタ濾材の第一のノズル列での紡糸軌道をＢから見た図である。 For example, as shown in FIG. 8 (the nozzle 9 and the center fiber track 20 when the first nozzle row 10 spins in a flat shape as viewed from above the nozzle 9). FIG. 8 is a view of the spinning trajectory at the first nozzle row of the air filter medium according to the second embodiment as viewed from B.
　第一のノズル列１０のノズル９が基材２上に紡糸をする際には、中心繊維１９は、第一のノズル列１０の動きと基材２の搬送により、蛇行したような中心繊維の軌道２０を描く。この時、中心繊維の軌道２０に沿って、第一の電荷集中部１７も蛇行する。また、第一のノズル列１０内のノズル９間で、中心繊維の軌道２０が重ならない部分は、端繊維１６が紡糸され第二の電荷集中部１８となる。さらに、中心繊維の直径αと中心繊維間の距離βの調整により、第二の電荷集中部１８を第一の電荷集中部１７で包囲することができる。また、図７のようにノズル９の配置が第一のノズル列１０と第二のノズル列１１で異なり、第二の電荷集中部１８の上層に第一の電荷集中部１７を紡糸することができる。これにより、複数の細繊維集合体５からなる多層構造に紡糸することで、第二の電荷集中部１８を第一の電荷集中部１７で３次元的に包囲することができる。 When the nozzle 9 of the first nozzle row 10 is spun onto the base material 2, the center fiber 19 is formed of the center fiber that is meandered by the movement of the first nozzle row 10 and the transport of the base material 2. Draw a trajectory 20. At this time, the first charge concentration portion 17 also meanders along the track 20 of the center fiber. Also, the end fiber 16 is spun into a second charge concentration portion 18 where the center fiber track 20 does not overlap between the nozzles 9 in the first nozzle row 10. Furthermore, the second charge concentration portion 18 can be surrounded by the first charge concentration portion 17 by adjusting the diameter α of the center fiber and the distance β between the center fibers. Further, as shown in FIG. 7, the arrangement of the nozzles 9 is different between the first nozzle row 10 and the second nozzle row 11, and the first charge concentration portion 17 can be spun on the upper layer of the second charge concentration portion 18. it can. Accordingly, the second charge concentration portion 18 can be three-dimensionally surrounded by the first charge concentration portion 17 by spinning into a multilayer structure composed of a plurality of fine fiber assemblies 5.
　構造例として、図６で示す細繊維集合体５が３層からなる細繊維層４では、最上層１３と最下層１４が第２の細繊維集合体７で、内部層１５が第１の細繊維集合体６である。図６に示すように、第１の細繊維集合体６の平面方向においても第二の電荷集中部１８が第一の電荷集中部１７に包囲された状態を実現しているものである。つまり、負の電荷が正の電荷に３次元的に包囲された状態である。 As a structural example, in the fine fiber layer 4 in which the fine fiber aggregate 5 shown in FIG. 6 is composed of three layers, the uppermost layer 13 and the lowermost layer 14 are the second fine fiber aggregate 7, and the inner layer 15 is the first fine fiber aggregate. This is a fiber assembly 6. As shown in FIG. 6, a state in which the second charge concentration portion 18 is surrounded by the first charge concentration portion 17 also in the planar direction of the first fine fiber aggregate 6 is realized. That is, the negative charge is three-dimensionally surrounded by the positive charge.
　また、正の電荷が負の電荷に包括された状態を実現しても良い。これは、単位時間当たりの中心繊維１９と端繊維１６の紡糸量、中心繊維の直径αと中心繊維間の距離β、ノズル９の可動速度、基材２の搬送速度などの調整で作製が可能である。 Further, a state in which positive charges are included in negative charges may be realized. This can be produced by adjusting the spinning amount of the center fiber 19 and the end fiber 16 per unit time, the center fiber diameter α and the distance β between the center fibers, the moving speed of the nozzle 9, the transport speed of the substrate 2, and the like. It is.
　これにより、第一の電荷集中部１７および第二の電荷集中部１８が全体を包囲されたため局所的な電荷を強めることとなるので、平面方向に対しても積層方向に対しても強い電界を形成できる。つまり、通過する粉塵粒子の誘電分極効果の向上と細繊維層のクーロン力により、エアフィルタ濾材１の粒子捕集性能を著しく向上させることが出来る。また、平面方向に包括した電荷が放出されにくくなり、長時間帯電状態を維持することができる。 As a result, since the first charge concentration portion 17 and the second charge concentration portion 18 are entirely surrounded, the local charge is strengthened, so that a strong electric field is generated in both the planar direction and the stacking direction. Can be formed. That is, the particle collecting performance of the air filter medium 1 can be remarkably improved by improving the dielectric polarization effect of the passing dust particles and the Coulomb force of the fine fiber layer. Further, it becomes difficult to release charges included in the plane direction, and the charged state can be maintained for a long time.
　したがって粉塵粒子の捕集効率を上げることができ、大気や細繊維層４の端面からの帯電放出が低減され、細繊維層の帯電状態をさらに長時間保持できるようになる。 Therefore, the collection efficiency of dust particles can be increased, the discharge of charge from the atmosphere and the end face of the fine fiber layer 4 is reduced, and the charged state of the fine fiber layer can be maintained for a longer time.
　また、エアフィルタ濾材１は、細繊維３の平均繊維径が１００～２０００ｎｍの繊維で構成されていることが好ましい。繊維径が１００ｎｍより細いと、自己支持性が弱く、破損しやすいので好ましくない。一方、繊維径が２０００ｎｍより太いと、細繊維３が形成する３次元網目構造の細孔が大きくなり、大気中の粉塵等を引き寄せるクーロン力が弱くなるため、捕集効率の低下を招くため好ましくない。より好ましくは細繊維３の平均繊維径は、５００ｎｍ～１５００ｎｍである。 The air filter medium 1 is preferably composed of fibers having an average fiber diameter of the fine fibers 3 of 100 to 2000 nm. If the fiber diameter is smaller than 100 nm, the self-supporting property is weak and it is easy to break. On the other hand, when the fiber diameter is larger than 2000 nm, the pores of the three-dimensional network structure formed by the fine fibers 3 are increased, and the Coulomb force that attracts dust in the atmosphere is weakened. Absent. More preferably, the average fiber diameter of the fine fibers 3 is 500 nm to 1500 nm.
　これにより、細孔を小さくできるので、さえぎりや拡散などの機械的捕集による捕集効率を向上することができる。さらに、細繊維３間の距離が短くなることで、電界強度が強くなり、静電気力による捕集効率を向上することができる。結果として、より捕集効率を向上することができる。また、繊維径を細くすることで、細繊維３近傍における空気流れの変化を小さくできるので、乱流を抑制でき、圧力損失を低減することができる。 As a result, the pores can be made smaller, so that the collection efficiency by mechanical collection such as blocking or diffusion can be improved. Furthermore, since the distance between the fine fibers 3 is shortened, the electric field strength is increased, and the collection efficiency by electrostatic force can be improved. As a result, the collection efficiency can be further improved. Moreover, since the change of the air flow in the fine fiber 3 vicinity can be made small by making a fiber diameter thin, a turbulent flow can be suppressed and a pressure loss can be reduced.
　また、繊維径を細くすることで、曲率が大きくなり、細繊維３表面の電荷密度が増加し、静電気力が強くなるので、細繊維３近傍の粉塵粒子を吸引しやすくなる。結果、エアフィルタ濾材１の粉塵粒子の捕集効率を向上することができる。 Further, by reducing the fiber diameter, the curvature is increased, the charge density on the surface of the fine fiber 3 is increased, and the electrostatic force is increased, so that dust particles in the vicinity of the fine fiber 3 are easily sucked. As a result, the dust particle collection efficiency of the air filter medium 1 can be improved.
　ここでの繊維径は、ほぼ正規分布となり、繊維径の数値は、中心径の数値で標準偏差のばらつきを含んだ数値である。 [The fiber diameter here is almost a normal distribution, and the numerical value of the fiber diameter is a numerical value of the center diameter including the variation of the standard deviation.
　以下本発明を実施例により説明するが、本発明は、これらの実施例に限定されるものではない。また、実施例と比較例における評価項目は以下の手法で実施した。 Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples. Moreover, the evaluation items in the examples and comparative examples were carried out by the following methods.
　（平均繊維径）
　得られた濾材の表面を走査型電子顕微鏡（倍率１００００倍）で撮影し、その画像から２０本の繊維径を測定し、平均値を算出した。 (Average fiber diameter)
The surface of the obtained filter medium was photographed with a scanning electron microscope (magnification 10,000 times), 20 fiber diameters were measured from the image, and an average value was calculated.
　（帯電分布）
　帯電トナー（春日電機株式会社製）を濾材に散布し、過剰なトナーを払い落とすことで、帯電状態を確認した。 (Charge distribution)
Charged toner (manufactured by Kasuga Denki Co., Ltd.) was sprayed on the filter medium, and the excess toner was removed to confirm the charged state.
　（濾材の性能評価）
　粉塵粒子の捕集効率は、濾材をダクト内に配置し、濾材の通過面風速が６．５ｃｍ／秒の濾材上流と下流における大気塵の粒子径０．３～０．５μｍの粒子数を、パーティクルカウンター（カノマックス社製、Ｍｏｄｅｌ３８８７）で１サンプル当り３回測定し、上流側と下流側の粒子数の比率から算出した。圧力損失は、捕集効率の評価時に平行して、濾材上流と下流の静圧差を差圧計で読み取った。 (Performance evaluation of filter media)
The collection efficiency of dust particles is the number of particles with a particle diameter of 0.3 to 0.5 μm in the air dust upstream and downstream of the filter medium where the filter medium is placed in the duct and the air velocity at the passage surface of the filter medium is 6.5 cm / sec. Measurement was performed three times per sample with a particle counter (manufactured by Kanomax Co., Model 3887), and calculation was performed from the ratio of the number of particles on the upstream side and downstream side. In parallel with the evaluation of the collection efficiency, the pressure loss was obtained by reading the difference in static pressure upstream and downstream of the filter medium with a differential pressure gauge.
　測定した捕集効率と圧力損失から、下記の計算式よりＱＦ値を算出した。ＱＦ値が大きい程、エアフィルタ濾材として高性能となる。 QF value was calculated from the following calculation formula from the measured collection efficiency and pressure loss. The larger the QF value, the higher the performance as an air filter medium.
　ＱＦ［１／Ｐａ］＝－ｌｎ（１－捕集効率［％］／１００）／圧力損失［Ｐａ］
　（実施例１）
　実施の形態１に示す製造方法によって、濾材を作製した。基材２として、目付量９８ｇ／ｍ２のポリエチレンテレフタレート（ＰＥＴ、ＰｏｌｙＥｔｈｙｌｅｎｅＴｅｒｅｐｈｔｈａｌａｔｅ）不織布を、高分子ポリマー溶液として、ポリスチレンをＮ，Ｎ－ジメチルアセトアミドに溶解した２４重量％を用いて、細繊維３を紡糸することにより、細繊維層４を形成した濾材を得た。その後、繊維径と濾材の捕集効率、及び、帯電分布の状態を評価した。図９は、実施例における繊維径と濾材の捕集効率および帯電分布の状態を評価した結果を示す図である。 QF [1 / Pa] =-ln (1-capturing efficiency [%] / 100) / pressure loss [Pa]
Example 1
A filter medium was produced by the manufacturing method shown in the first embodiment. Fine fiber 3 is used as base material 2 by using a polyethylene terephthalate (PET) non-woven fabric having a weight per unit area of 98 g / m 2 and a polymer solution of 24% by weight of polystyrene dissolved in N, N-dimethylacetamide. A filter medium on which the fine fiber layer 4 was formed was obtained by spinning. Thereafter, the fiber diameter, the collection efficiency of the filter medium, and the state of charge distribution were evaluated. FIG. 9 is a diagram showing the results of evaluating the fiber diameter, the collection efficiency of the filter medium, and the state of charge distribution in the examples.
　（比較例１）
　ポリエーテルサルホン（Ｐｏｌｙｅｔｈｅｒ　Ｓｕｌｆｏｎｅ）をＮ，Ｎ－ジメチルアセトアミドに溶解した２５重量％の高分子ポリマー溶液を、実施例１と同様の方法で紡糸し、濾材を得た。その後、繊維径と濾材の捕集効率、及び、帯電分布の状態を評価した。評価結果を図９に示す。 (Comparative Example 1)
A 25 wt% polymer solution in which polyethersulfone was dissolved in N, N-dimethylacetamide was spun in the same manner as in Example 1 to obtain a filter medium. Thereafter, the fiber diameter, the collection efficiency of the filter medium, and the state of charge distribution were evaluated. The evaluation results are shown in FIG.
　（比較例２）
　ポリフッ化ビニリデンをＮ，Ｎ－ジメチルアセトアミドに溶解した２０重量％の高分子ポリマー溶液を、実施例１と同様の方法で紡糸し、濾材を得た。その後、繊維径と濾材の捕集効率、及び、帯電分布の状態を評価した。評価結果を図９に示す。 (Comparative Example 2)
A 20 wt% polymer solution in which polyvinylidene fluoride was dissolved in N, N-dimethylacetamide was spun in the same manner as in Example 1 to obtain a filter medium. Thereafter, the fiber diameter, the collection efficiency of the filter medium, and the state of charge distribution were evaluated. The evaluation results are shown in FIG.
　（比較結果）
　体積抵抗が１０＾１６Ωｃｍ以上、且つ、誘電正接が０．００１以下であるポリスチレンを用いた実施例１では、集合体が交互に積層している帯電分布が確認でき、高いＱＦ値を示した。 (Comparison result)
In Example 1 using polystyrene having a volume resistance of 10 ^ 16 Ωcm or more and a dielectric loss tangent of 0.001 or less, a charge distribution in which the aggregates are alternately stacked was confirmed, and a high QF value was exhibited.
　一方、体積抵抗と誘電正接の少なくとも１つが条件を満たさないポリエーテルサルホンとポリフッ化ビニリデンでは、帯電トナーが付着せずに、ＱＦ値が低いものであった。 On the other hand, in the polyether sulfone and polyvinylidene fluoride in which at least one of the volume resistance and the dielectric loss tangent does not satisfy the condition, the charged toner does not adhere and the QF value is low.
　本発明のエアフィルタ濾材は、捕集効率を著しく向上させ、長期間維持できるとともに、圧力損失を低くしたものである。従って、家庭用や事務所用などのエアフィルタ、およびこのエアフィルタを備えた空気清浄装置として活用が期待されるものである。 The air filter medium of the present invention significantly improves the collection efficiency, can be maintained for a long time, and has a low pressure loss. Therefore, it is expected to be utilized as an air filter for home use or office use, and an air purifying apparatus equipped with this air filter.
１，１００　エアフィルタ濾材
２　基材
３　細繊維
４　細繊維層
５　細繊維集合体
６　第１の細繊維集合体
７　第２の細繊維集合体
８　搬送部
９　ノズル
１０　第一のノズル列
１１　第二のノズル列
１２　第三のノズル列
１３　最上層
１４　最下層
１５　内部層
１６　端繊維
１７　第一の電荷集中部
１８　第二の電荷集中部
１９　中心繊維
２０　中心繊維の軌道
α　中心繊維の直径
β　中心繊維間の距離 1,100 Air filter medium 2 Base material 3 Fine fiber 4 Fine fiber layer 5 Fine fiber aggregate 6 First fine fiber aggregate 7 Second fine fiber aggregate 8 Conveying section 9 Nozzle 10 First nozzle array 11 First Second nozzle row 12 Third nozzle row 13 Uppermost layer 14 Lowermost layer 15 Inner layer 16 End fiber 17 First charge concentration portion 18 Second charge concentration portion 19 Center fiber 20 Center fiber trajectory α Center fiber diameter β Distance between center fibers

Claims (5)

  1. 基材と、前記基材の表面上に設けた細繊維層とを備え、
    前記細繊維層は、複数の細繊維集合体からなる多層構造体であって、
    前記細繊維を形成するポリマーの体積抵抗率が１０＾１６Ωｃｍ以上且つ、誘電正接が０．００１以下であり、
    前記各細繊維集合体が平面方向には全体面積の９０％以上に帯電が分布し、局所的な部分での積層方向には、正の電荷を多く帯びた第１の細繊維集合体と、負の電荷を多く帯びた第２の細繊維集合体とが、積層されていることを特徴とするエアフィルタ濾材。     A base material, and a fine fiber layer provided on the surface of the base material,
    The fine fiber layer is a multilayer structure composed of a plurality of fine fiber aggregates,
    The volume resistivity of the polymer forming the fine fiber is 10 ^ 16 Ωcm or more and the dielectric loss tangent is 0.001 or less,
    In the plane direction, each fine fiber aggregate has a charge distribution in 90% or more of the entire area, and in the laminating direction at a local portion, a first fine fiber aggregate having a lot of positive charges, An air filter medium characterized in that a second fine fiber aggregate having a lot of negative charges is laminated.
  2. 前記第１の細繊維集合体と前記第２の細繊維集合体とが交互に３層以上に積層されていることを特徴とする請求項１に記載のエアフィルタ濾材。 The air filter medium according to claim 1, wherein the first fine fiber aggregates and the second fine fiber aggregates are alternately laminated in three or more layers.
  3. 前記細繊維集合体の内部において、平面方向かつ積層方向において、電荷の局所的な偏りが逆電荷で包括された状態であることを特徴とする請求項１または２に記載のエアフィルタ濾材。 3. The air filter medium according to claim 1, wherein in the fine fiber aggregate, a local bias of electric charge is covered by a reverse electric charge in a planar direction and a laminating direction. 4.
  4. 前記細繊維がポリスチレンからなる請求項１に記載のエアフィルタ濾材。 The air filter medium according to claim 1, wherein the fine fibers are made of polystyrene.
  5. 前記細繊維の平均繊維径が１００ｎｍ～２０００ｎｍの繊維から構成されたことを特徴とする請求項１に記載のエアフィルタ濾材。 The air filter medium according to claim 1, wherein the fine fibers are composed of fibers having an average fiber diameter of 100 nm to 2000 nm.
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Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5876118A (en) * 1981-10-30 1983-05-09 Koken Kk Multilayer structured filter
JPS61181511A (en) * 1985-02-06 1986-08-14 Toray Ind Inc Filter medium
JPS62102809A (en) * 1985-10-28 1987-05-13 Mitsui Petrochem Ind Ltd Nonwoven fabric filter converted to electret
JPS62197118A (en) * 1986-02-24 1987-08-31 Toray Ind Inc Laminated electret filter
JPH04326911A (en) * 1991-04-25 1992-11-16 Toyobo Co Ltd Production of electret filter
JPH05154318A (en) * 1991-12-10 1993-06-22 Toshiba Corp Dust collecting filter for air purifier
WO1994012262A1 (en) * 1992-11-23 1994-06-09 W.L. Gore & Associates, Inc. Triboelectric filtration material
JPH09114183A (en) * 1995-10-23 1997-05-02 Ricoh Co Ltd Friction electrifying device
WO2013096672A1 (en) * 2011-12-21 2013-06-27 E. I. Du Pont De Nemours And Company Process for laying fibrous webs from a centrifugal spinning process

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5876118A (en) * 1981-10-30 1983-05-09 Koken Kk Multilayer structured filter
JPS61181511A (en) * 1985-02-06 1986-08-14 Toray Ind Inc Filter medium
JPS62102809A (en) * 1985-10-28 1987-05-13 Mitsui Petrochem Ind Ltd Nonwoven fabric filter converted to electret
JPS62197118A (en) * 1986-02-24 1987-08-31 Toray Ind Inc Laminated electret filter
JPH04326911A (en) * 1991-04-25 1992-11-16 Toyobo Co Ltd Production of electret filter
JPH05154318A (en) * 1991-12-10 1993-06-22 Toshiba Corp Dust collecting filter for air purifier
WO1994012262A1 (en) * 1992-11-23 1994-06-09 W.L. Gore & Associates, Inc. Triboelectric filtration material
JPH09114183A (en) * 1995-10-23 1997-05-02 Ricoh Co Ltd Friction electrifying device
WO2013096672A1 (en) * 2011-12-21 2013-06-27 E. I. Du Pont De Nemours And Company Process for laying fibrous webs from a centrifugal spinning process

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