WO2016088691A1 - Filtre électret - Google Patents

Filtre électret Download PDF

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Publication number
WO2016088691A1
WO2016088691A1 PCT/JP2015/083521 JP2015083521W WO2016088691A1 WO 2016088691 A1 WO2016088691 A1 WO 2016088691A1 JP 2015083521 W JP2015083521 W JP 2015083521W WO 2016088691 A1 WO2016088691 A1 WO 2016088691A1
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WO
WIPO (PCT)
Prior art keywords
fluorine
containing polymer
filter
electret
fiber
Prior art date
Application number
PCT/JP2015/083521
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English (en)
Japanese (ja)
Inventor
北川　義幸
Original Assignee
東洋紡株式会社
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Publication date
Application filed by 東洋紡株式会社 filed Critical 東洋紡株式会社
Priority to JP2016562430A priority Critical patent/JP6743705B2/ja
Publication of WO2016088691A1 publication Critical patent/WO2016088691A1/fr

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Classifications

    • 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
    • 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
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/12—Layered products comprising a layer of synthetic resin next to a fibrous or filamentary layer
    • 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
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F14/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen
    • C08F14/18—Monomers containing fluorine
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
    • D06M15/19—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with synthetic macromolecular compounds
    • D06M15/21—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D06M15/263—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of unsaturated carboxylic acids; Salts or esters thereof
    • D06M15/277—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of unsaturated carboxylic acids; Salts or esters thereof containing fluorine

Definitions

  • the present invention relates to an electret filter.
  • fiber layer filters made of various fibers have been used as air purification filters. Since the fiber layer filter has a large porosity, it has an advantage that the ventilation resistance is lower and the life is longer than that of a filter using a membrane or a particle packed layer. Furthermore, since the degree of freedom of shape is high, the fiber layer filter is widely used for dust masks, various air conditioning elements, air purifiers, and the like.
  • particles are captured on the fiber by a mechanical collection mechanism such as contact adhesion, diffusion, inertial collision, and the like. These mechanisms vary depending on the physical properties of the particles, the fiber diameter, the passing wind speed, etc., but in practical use environments, particles with an aerodynamic equivalent diameter of about 0.1 to 1.0 ⁇ m have a trapping efficiency of the filter. It is known to be lower.
  • a method using electric attraction in combination is known.
  • a method of applying a charge to particles to be collected a method of applying a charge to a filter, or a combination of both methods are known.
  • a method for applying a charge to a filter a method in which a filter is disposed between electrodes and dielectric polarization is performed during ventilation, and a method in which a long-life electrostatic charge is applied to an insulating material are known. In particular, in the latter case, energy such as an external power source is not required. Therefore, a filter containing such an insulating material is widely used as an electret filter.
  • the electret filter described above has a drawback that electrostatic attraction decreases as the collection of particles proceeds. Especially when collecting mist-like particles that are liquid, the entire fiber surface gets wet, and the insulating material In this case, since the leakage and neutralization of charges are promoted, the collection efficiency is remarkably lowered. In order to solve this problem, by reducing the surface tension of the filter, the spreading of the mist-like particles on the fiber surface and the diffusion into the fiber is suppressed, and the shape of the mist-like particles is made close to a sphere, thereby obtaining mechanical capture. There is known a method for improving the collection efficiency of particles by a collection mechanism (hereinafter referred to as collection efficiency or collection efficiency of particles).
  • a polyolefin resin As a material for a general electret filter, a polyolefin resin, a polyester resin, a polycarbonate resin, a phenol resin, or the like excellent in charge stability is used.
  • polyolefin resins such as polypropylene, polyethylene, and polymethylpentene having the smallest surface tension are used, oil mist represented by poly- ⁇ -olefin (PAO), dioctyl phthalate (DOP), etc. Does not exhibit liquid repellency.
  • PAO poly- ⁇ -olefin
  • DOP dioctyl phthalate
  • Patent Document 1 a method of mixing an additive having a perfluoro group with a resin (for example, Patent Document 1), a method of coating a surface with an emulsion processing agent having a perfluoro group (for example, Patent Document 2), a fluorine gas treatment or plasma.
  • Oil mist resistance by reducing the surface tension of the electret filter while maintaining charge stability by the method of introducing fluorine atoms into the polymer constituting the filter by replacing constituent elements in the treatment eg Patent Document 3
  • fluororesins and fluorine-based low molecular additives are not suitable for melt spinning, and toxic gases such as hydrogen fluoride and carbonyl fluoride are generated as thermal decomposition products.
  • the introduction method of fluorine atoms by fluorine gas treatment or plasma treatment has a high degree of processing difficulty such as toxicity of fluorine gas and increase in hydrophilicity due to residual oxygen.
  • a processing agent developed for textiles it is easy to obtain oil repellency by coating with this processing agent, but processing agents developed for textiles give priority to softness. In other words, an acrylate processing agent developed for textiles cannot provide sufficient charge stability and does not have sufficient performance as an electret filter.
  • PFOS perfluorooctane sulfonic acid
  • PFOA perfluorooctanoic acid
  • a fluorine-based resin (for example, Patent Document 4) having both electret properties and coating properties is also known, but it is necessary to use a fluorine-based solvent for the coating solution, and the liquid retention property is not sufficient.
  • a fluorine-based solvent for the coating solution, and the liquid retention property is not sufficient.
  • the present invention has been given as an object to provide an electret filter that can be manufactured by a low-cost and simple method and has electret properties, oil repellency, and oil mist resistance.
  • the fluorine-containing polymer is a polymer containing a monomer having a fluorine-containing alkyl group or a fluorine-containing alkylene group having 7 or less carbon atoms, it adheres to the fiber layer composed of fibers and the surface of the fiber layer.
  • the inventors have found what can be done and have completed the present invention.
  • the present invention is an electret filter comprising a fiber layer made of fibers and an oil repellent layer containing a fluorine-containing polymer attached to the surface of the fiber layer, wherein the fluorine-containing polymer contains fluorine having 7 or less carbon atoms
  • the fluorine-containing polymer is preferably obtained by solution polymerization or emulsion polymerization, and the fluorine-containing polymer is obtained using an emulsifier other than an alkali metal salt and an alkaline earth metal salt. It is preferable that
  • an electret filter having excellent electret properties, oil repellency, and oil mist resistance can be obtained with a simple apparatus and process.
  • the filter of the present invention is an electret filter provided with a fiber layer composed of fibers and an oil repellent layer containing a fluorine-containing polymer attached to the surface of the fiber layer, and the glass transition temperature or melting point of the fluorine-containing polymer is 60. It is characterized by being over °C.
  • the constituent material of the fiber layer is not particularly limited as long as it has desired characteristics, but it is preferable to use a synthetic resin from the viewpoint of the degree of freedom in shape, and more preferably, a synthetic resin containing no fluorine is used. It is. Specific materials include polyester, polycarbonate, polyamide, polyolefin, cyclic olefin, polyvinyl chloride, polyvinylidene chloride, and the like, and polyolefin materials such as polyethylene, polybutene, polypropylene, polymethylpentene, and cyclic olefin, and polystyrene materials are preferable. . By using these materials, an electret filter having high electrical resistance, a good balance of hydrophobicity, moldability, etc., and excellent particle collection efficiency, that is, an electret filter excellent in practicality is obtained. be able to.
  • the fiber layer used in the present invention may be a woven fabric shape, a nonwoven fabric shape, a cotton shape, or the like obtained by molding a fibrous material obtained by a known technique into an appropriate shape and thickness according to the application, From the viewpoint of particle removal performance, a non-woven fiber layer is preferable.
  • the method for forming the non-woven fiber layer is not particularly limited. For example, melt blown method, wet method, dry method, spunbond method, flash spinning method, electrospinning method, force spinning method, supersonic stretching method
  • the present invention can use a melt blown method, an electrospinning method, a force spinning method, or a supersonic speed.
  • the fiber layer may be molded from only one type of material, or may be molded using two or more types of materials.
  • the diameter of the fiber used in the present invention is preferably 0.001 to 100 ⁇ m, more preferably 0.005 to 20 ⁇ m, still more preferably 0.01 to 10 ⁇ m, and particularly preferably 0.02 to 5 ⁇ m. Most preferably, it is 0.03 to 3 ⁇ m. If the fiber diameter is within the above range, the air ventilation resistance in the fiber layer can be reduced while increasing the collection efficiency. When the fiber diameter is smaller than 0.001 ⁇ m, it is difficult to give an electric charge to the fiber layer, and when the fiber diameter is larger than 100 ⁇ m, the collection efficiency may be lowered. There is a large decrease in efficiency in various performances.
  • the cross-sectional shape of the fiber does not have to be a circle, but may be an ellipse, a rectangle, a star, a clover, or the like.
  • the liquid whose contact angle with the fiber surface is 90 ° or less is absorbed into the fiber groove by capillary action, so that the entire fiber can be prevented from being covered with the liquid, and the electret degradation can be suppressed. can do.
  • a known compounding agent may be added to the resin in order to suppress the deterioration of the resin itself and increase the charge stability in the fiber layer.
  • the compounding agent include various metal salts, antioxidants, light stabilizers and the like.
  • the fiber layer may be formed using a plurality of different materials. For example, two or more different resin components may be formed.
  • a compatible or incompatible blend polymer, ionomer, maleic acid-modified polyolefin, hindered phenol resin, hindered amine resin, or the like obtained by mixing can be used.
  • an oil repellent layer is provided to repel oil mist such as DOP and PAO contained in tobacco smoke, cooking oil, lubricating oil, agricultural chemicals and the like.
  • a fluorine-containing polymer is applied to the surface of the fiber layer to form an oil repellent layer.
  • this method is referred to as a post-processing method.
  • a fluorine-containing resin such as polytetrafluoroethylene (PTFE), perfluoroalkoxy fluororesin (PFA), or ethylene / tetrafluoroethylene copolymer (ETFE) to the resin composition for the fiber layer.
  • PTFE polytetrafluoroethylene
  • PFA perfluoroalkoxy fluororesin
  • ETFE ethylene / tetrafluoroethylene copolymer
  • thermoplastic resin since fibers made of thermoplastic resin are generally melt-spun into a fiber shape at about 200 to 300 ° C., a fluororesin or an additive is mixed with the thermoplastic resin at the thermoplastic resin production stage or spinning stage. However, if a post-processing method is used, the fiber layer can be produced by general equipment and processes.
  • a method of adhering the fluorine-containing polymer by immersing, applying, and spraying a solution or dispersion containing the fluorine-containing polymer on the fiber surface A method of attaching a fluorine-containing polymer in a molten state to a fiber layer, a method of dispersing a particulate fluorine-containing polymer in an air stream and attaching it to a fiber layer, a method of attaching a fluorine-containing polymer by a technique such as vapor deposition or sputtering Etc. can be used. Further, it is also preferable to promote or fix the film formation or molecular orientation on the fiber surface by performing a heat treatment as necessary.
  • a solution or a dispersion is used.
  • a method of attaching the fluorine-containing polymer to the fiber layer is preferred.
  • Fluorine-containing polymers are insoluble and difficult to mix with general-purpose organic solvents and water.
  • emulsions in which fluorine-containing polymers are dissolved in fluorine-containing solvents are dispersed in non-fluorine organic solvents or water, or fluorine-containing polymers.
  • a dispersion in which a room-temperature liquid substance is dispersed in a dispersion medium is referred to as an emulsion
  • a dispersion liquid in which a room-temperature solid substance is dispersed in a dispersion medium is referred to as a suspension.
  • the purpose is to adhere the fluorine-containing polymer to the fiber surface using the liquid, and according to the gist of the present invention, the mode of the dispersion including changes in the state of the dispersion due to cooling and heating is changed. Can do.
  • the fluorinated solvent has a higher boiling point than the liquid used as the dispersion medium, and if the boiling point is low, it is advantageous for maintaining the shape of the particles and dispersing and supporting the particles.
  • Preferred combinations can be used depending on the characteristics.
  • the fluorine-containing polymer used for forming the oil-repellent layer may be any monomer component including a monomer having a fluorine-containing alkyl group or a fluorine-containing alkylene group having 7 or less carbon atoms.
  • a fluorine-containing polymer having thermoplasticity such as PFA / ETFE / low molecular weight PTFE can be used.
  • fluorine-containing polymers such as copolymers composed of fluorine-containing olefins containing fluorine-containing alkyl groups, fluorine-containing alkylene groups, and fluorine-containing (meth) acrylates having a fluoroalkyl group in the side chain
  • a copolymer containing a unit derived from a fluorine-containing monomer at least in part can be used.
  • the fluorine-containing olefins containing a fluorine-containing alkyl group and / or a fluorine-containing alkylene group preferably have a perfluoroalkyl group and / or a perfluoroalkylene group.
  • the fluorine-containing alkyl group and / or fluorine-containing alkylene group preferably has 1 to 7 carbon atoms, more preferably 4 to 6 carbon atoms. More preferably, it has a perfluoroalkyl group consisting of carbon atoms at the end of the side chain.
  • the fluorine-containing (meth) acrylate preferably has a (meth) acryloyl group having a trifluoromethyl group located at the terminal.
  • the fluorine-containing polymer may contain oxygen, silicon, nitrogen atoms and the like as a linking group, but more preferably has a structure consisting of only hydrogen, fluorine, and carbon atoms.
  • a structure consisting of only hydrogen, fluorine, and carbon atoms since there are no unpaired atoms and asymmetric polar components, surface tension and hygroscopicity are reduced, and as a result, oil resistance and electret properties are improved.
  • the fluorine-containing polymer has one or more aromatic groups and linear / branched / cycloaliphatic groups as spacers with the main chain.
  • ⁇ -chloro (meth) acrylate is used as the main chain, a chlorine atom having a large steric hindrance can be incorporated into the main chain, so that the polymer content can be maintained while maintaining a high content ratio of the fluorine-containing monomer. As a result, a high glass transition temperature can be obtained, and charge stability and oil repellency can be easily improved.
  • a monomer having a short-chain fluorine-containing alkyl group or fluorine-containing alkylene group in order to obtain a desired glass transition temperature or crystallinity, as a monomer copolymerized with these fluorine-containing monomers, carbon is used.
  • a (meth) acrylate having a branched aliphatic hydrocarbon group, a cyclic aliphatic hydrocarbon group, or an aromatic hydrocarbon group can be used.
  • examples include cycloalkyl groups such as cyclohexyl group; polycyclic aliphatic hydrocarbon groups having 7 to 20 carbon atoms such as norbornyl group, bornyl group, isobornyl group, adamantyl group; phenyl group, naphthyl group, benzyl group, etc.
  • (Meth) acrylate having an aromatic hydrocarbon group is
  • the resulting copolymer has a high melting point or glass transition temperature, and further blocks the ester group and reduces molecular mobility, so that it has electret properties. The stability of is improved.
  • Examples of the (meth) acrylate include cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, bornyl (meth) acrylate, adamantyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, Examples include tricyclodecanyl (meth) acrylate, phenyl (meth) acrylate, naphthyl (meth) acrylate, benzyl (meth) acrylate, and 2-t-butylphenyl (meth) acrylate.
  • a homopolymer having a cyclic aliphatic hydrocarbon group is characterized by a significantly higher glass transition temperature than a homopolymer having a linear aliphatic hydrocarbon group, while maintaining a high content ratio of the fluorine-containing monomer. As a polymer, a high glass transition temperature can be obtained.
  • a monomer having a halogenated olefin, a functional group having crosslinkability, a hindered phenol structure or a hindered amine structure imparting an antioxidant action and charge stability can also be used.
  • the halogenated olefin is preferably used as long as it has 2 or more carbon atoms. Examples thereof include vinyl chloride, vinyl bromide, vinyl iodide, vinylidene chloride, vinylidene bromide, and vinylidene iodide.
  • the copolymerization ratio of the fluorine-containing monomer and the non-fluorine monomer is preferably in the range of 100: 0 to 10:90, more preferably 100: 0 to 20:80, and still more preferably 100: 0. ⁇ 30: 70.
  • the melting point or glass transition temperature of the fluorine-containing polymer is preferably 60 ° C. or higher, more preferably 80 ° C. or higher, still more preferably 100 ° C. or higher, and most preferably 120 ° C. or higher. This is because it has the following effects. (1) Since the viscosity of the emulsion or suspension is reduced, blocking of particles in the dispersion is reduced. (2) The fluidity of the fluorine-containing polymer is lowered, and the loss of electric charge due to the spread of the fluorine-containing polymer on the fiber after electret processing can be suppressed.
  • the melting point of the fiber used as the base material is crystalline. It is preferable that the glass transition temperature or melting point of the fluorine-containing polymer is lower than the glass transition temperature or melting point of the fluorine-containing polymer lower than the glass transition temperature when the base fiber is amorphous. preferable.
  • the glass transition temperature of the fluorine-containing polymer is preferably 60 to 170 ° C., more preferably 80 ° C. to 170 ° C., still more preferably 100 ° C. to 170 ° C.
  • the melting point of the fluorine-containing polymer is preferably 60 to 170 ° C, more preferably 80 to 170 ° C, and still more preferably 100 to 170 ° C. Most preferably, it is 120 ° C to 170 ° C.
  • a well-known polymerization method can be used for the fluorine-containing polymer.
  • Anionic polymerization, cationic polymerization, radical polymerization and the like can be selected as necessary, and stereoregular polymerization is preferable.
  • Radical polymerization is preferred because the polymerization conditions are mild and the fluorine-containing polymer used in the present invention can be easily obtained.
  • Specific examples of radical polymerization include known solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization and the like.
  • a monomer is dissolved in an organic solvent, and after substitution with nitrogen as necessary, light, heat, and radiation are irradiated to polymerize under the activation conditions of the radical polymerization initiator.
  • Polymerization is preferably performed by heating and stirring at 0 to 120 ° C. for 1 to 10 hours.
  • the polymerization initiator is not particularly limited as long as it is soluble in a solvent, but azo polymerization initiators, peroxide polymerization initiators and the like are preferably used.
  • azobisisobutyronitrile azobisisobutyronitrile
  • benzoyl peroxide Polymerization initiators such as di-t-butyl peroxide, lauryl peroxide, cumene hydroperoxide, t-butyl peroxypivalate, and diisopropyl peroxydicarbonate can be selected according to the desired reaction rate and conditions.
  • the polymerization initiator is preferably added in an amount of 0.01 to 20 parts by mass, more preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the monomer.
  • organic solvent used for the solution polymerization a known organic solvent can be used depending on the reaction temperature and solubility as long as it is not polymerizable with the monomer and dissolves the monomer.
  • the monomer in the presence of a polymerization initiator and an emulsifier, the monomer is emulsified in water or a mixture of water and a water-soluble organic solvent, and after nitrogen substitution as necessary, light, heat, It is irradiated with radiation and polymerized under the activation conditions of the radical polymerization initiator.
  • Polymerization is preferably performed by heating and stirring at 0 to 100 ° C. for 1 to 10 hours.
  • Polymerization initiators include benzoyl peroxide, lauroyl peroxide, t-butyl perbenzoate, 1-hydroxycyclohexyl hydroperoxide, 3-carboxypropionyl peroxide, acetyl peroxide, azobisisobutylamidine dihydrochloride, Water-soluble initiators such as azobisisobutyronitrile, sodium peroxide, potassium persulfate, ammonium persulfate, azobisisobutyronitrile, benzoyl peroxide, di-t-butyl peroxide, lauryl peroxide, cumene hydroper Oil-soluble initiators such as oxide, t-butyl peroxypivalate and diisopropyl peroxydicarbonate can be selected according to the desired reaction rate and conditions.
  • the polymerization initiator is preferably added in an amount of 0.01 to 20 parts by mass, more preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the monomer
  • water-soluble organic solvent examples include acetone, methyl ethyl ketone, ethyl acetate, propylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol, tripropylene glycol, and ethanol.
  • the water-soluble organic solvent is 1 in 100 parts by mass of water. It is preferable to add ⁇ 50 parts by mass, more preferably 10 to 40 parts by mass.
  • the compound preferably used as the emulsifier is not particularly limited as long as it has desired characteristics, but fluorine-containing carboxylic acids, fluorine-containing alcohols, fluorine-containing sulfonic acids, fluorine-containing ethers, fluorine-containing esters, fluorine-containing amines Examples can be given.
  • monofunctional carboxylic acids, alcohols, sulfonic acids, ethers, esters, and amines having a perfluoroalkyl group having 7 or less carbon atoms (more preferably 6 or less carbon atoms); 7 or less carbon atoms (more preferably carbon number) 6 or less) bifunctional carboxylic acid having a perfluoroalkylene group, alcohol, sulfonic acid, ether; fluorine-containing compound other than perfluoro group; and the like can be preferably used.
  • the compound preferably used as an emulsifier is preferably a metal salt other than an alkali metal or an alkaline earth metal, or consists of only an organic component or a nonionic metal component (for example, a silicone compound).
  • An emulsifier made of an alkali metal salt or an alkaline earth metal salt is difficult to be decomposed or removed by transpiration, and there is a risk that electret properties may be lowered due to dissociation characteristics when moisture or polar mist is adhered.
  • it preferably has a trifluoromethyl group as a terminal structure.
  • perfluorohexanoic acid boiling point 160 ° C.
  • perfluorohexanesulfonic acid in the case of 6 carbon atoms.
  • Perfluoroheptanoic acid (boiling point 175 ° C.), perfluoroheptanesulfonic acid, or ammonium salts thereof can be preferably used, and ether bonds such as CF 3 CF 2 (O) m CF 2 CF 2 OCF 2 COOH
  • ether bonds such as CF 3 CF 2 (O) m CF 2 CF 2 OCF 2 COOH
  • the emulsifier is a carboxylic acid (terminal group H type)
  • the emulsifier can be volatilized and evaporated at a boiling point or higher of the compound used as the emulsifier, and it is preferable that the emulsifier can be volatilized and evaporated even at a temperature below the boiling point. It is possible to obtain an excellent dispersion that maintains both electret maintenance and processability of the fluorine-containing polymer used for fiber and / or fiber surface processing as a base material.
  • the volatilization removal condition can be selected at any temperature as long as the temperature is not lower than the normal temperature and lower than the melting point of the substrate, but is preferably 60 ° C. or higher, more preferably 80 ° C. or higher, more preferably 100 ° C. or higher.
  • the removal of the emulsifier from the inside of the resin and the vicinity of the surface is promoted by setting the volatilization temperature of the emulsifier to be equal to or higher than the glass transition temperature of the fluorine-containing polymer used for the surface processing.
  • an emulsion or suspension obtained by emulsion polymerization or suspension polymerization is used directly or diluted, and a fluorine-containing polymer solution obtained by solution polymerization is dispersed or emulsified in a fluorine-free solvent.
  • a fluorine-containing polymer obtained by emulsion polymerization / bulk polymerization / suspension polymerization is dispersed or emulsified in a fluorine-free solvent, and a fluorine-containing polymer obtained by emulsion polymerization / bulk polymerization / suspension polymerization is fluorine-containing.
  • the liquid used for dispersion preferably contains at least one fluorine-free organic solvent and water, and more preferably contains water.
  • the fluorine-containing polymer is contained on the particle side.
  • the particle size of the fluorine-containing polymer is preferably 1 nm to 100 ⁇ m, more preferably 2 nm to 10 ⁇ m, and even more preferably 3 nm to 5 ⁇ m. And most preferably 5 nm to 2 ⁇ m. If it exceeds 100 ⁇ m, penetration and adhesion are difficult, and if it is less than 1 nm, dispersion is difficult and a large amount of emulsifier needs to be used.
  • an emulsifier or a dispersant is used in the polymerization, dispersion, or emulsification to increase the affinity between the solid or liquid containing the fluorine-containing polymer and the water or non-fluorine organic solvent as the dispersion medium.
  • the emulsifier and the dispersant are not particularly limited as long as good dispersion characteristics can be obtained.
  • the fluorine-containing polymer used in the present invention is intended to provide oil repellency, and therefore has a low surface tension. Therefore, it is preferable to use a fluorine-containing emulsifier or a fluorine-containing solvent.
  • At least a part of the fiber layer or at least a part of the oil repellent layer is electretized.
  • Electretization is not particularly limited as long as desired characteristics can be obtained when the filter is used, and electretization may be performed at any timing after the single fiber, during sheet molding, or after sheet molding.
  • known methods such as polarization by high voltage, collision of charged ions, collision / injection of charged particles, frictional charging, contact charging / collision charging with vapor / condensed liquid / sprayed liquid, etc. should be used. Can do.
  • a plurality of steps may be performed in one step. That is, the coating of the fluorine-containing polymer and the electret process using a liquid or the like may be performed in one process, and the cleaning process such as the removal of the surfactant, degreasing and particle cleaning and the electret process are performed in one process. You may go on. Moreover, as an electretization process, you may charge a fluorine-containing polymer previously in a dispersion liquid, and you may make the charged fluorine-containing polymer adhere to a fiber.
  • the droplets of the test liquid used in JIS K 6768 or the liquid mixture for the wet tension test used in the AATCC-118 method are brought into contact with each other for 30 seconds. Based on the measured surface tension, the smaller the measured surface tension, the higher the oil repellency.
  • the surface tension is preferably 35 mN / m or less, more preferably 30 mN / m or less, still more preferably 28 mN / m or less, and most preferably 25 mN / m or less.
  • These materials have a surface tension of 31 mN / m bis (2-ethylhexyl) phthalate (DOP), which is a standard for liquid particles in the national certification standards for dust masks, and are one of poly- ⁇ -olefins (PAO)
  • DOP (2-ethylhexyl) phthalate
  • PAO poly- ⁇ -olefins
  • a fiber layer having an oil absorbing function or a water absorbing function (hereinafter referred to as a liquid absorbing layer).
  • a non-fluorine material is used as the fiber layer, it has an oil absorbing function even when a general-purpose resin such as polyethylene or polypropylene is laminated.
  • the material of the liquid-absorbing layer is not particularly limited as long as it absorbs liquid droplets, but is a fiber sheet material composed of polypropylene, polyethylene, polystyrene, polyamide, polyacrylonitrile, polyester, polycarbonate, cellulose, rayon, activated carbon, zeolite
  • a sheet material containing a porous material such as pulp in the gap or processed into a surface is preferable. More preferably, it is an olefin fiber sheet material such as polypropylene, polyethylene, polystyrene, or the like, or a fiber sheet material made of polyester, and more preferably a fiber sheet material made of polypropylene.
  • the fibers constituting the liquid absorption layer preferably have a diameter of 0.005 to 100 ⁇ m, more preferably 0.01 to 20 ⁇ m, still more preferably 0.5 to 10 ⁇ m, and 1 to 5 ⁇ m. Most preferably it is.
  • the fibers used in the liquid absorbing layer can be used alone or in combination of two or more, and the material can be selected from the viewpoints of collecting coarse particles and ventilation resistance.
  • the material used for the liquid absorbing layer may be a non-electret material or an electret material, but is preferably an electret material.
  • the production method of the liquid absorbing layer is not particularly limited as long as the desired properties can be obtained, but it is not limited by the thermal bond method, the spun bond method, the spun lace method, the melt electro spinning method, the solution electro spinning method, the force spinning method, or the like. It can be produced using a sheet material.
  • the filter of the present invention can be used in combination with layers such as a prefilter layer, a fiber protective layer, a functional fiber layer, and a reinforcing layer as necessary. These layers may be layers formed by adhering the fluorine-containing polymer used in the present invention.
  • Examples of the prefilter layer and the fiber protective layer include a spunbond nonwoven fabric, a thermal bond nonwoven fabric, and urethane foam.
  • Examples of the functional fiber layer include antibacterial, antiviral, colored fiber layers for identification and design purposes.
  • Examples of the reinforcing layer include a thermal bond nonwoven fabric and various nets.
  • the filter of the present invention can be widely used as a filter for removing oil mist.
  • the filter of the present invention can be used, for example, for protection of dust and gas masks, home air purifiers, building and vehicle ventilation systems, and various devices.
  • Test solutions from grade 1 to grade 8 defined in AATCC118 were prepared. Each was placed on the surface of a sample (filter after electretization) with a micropipettor for microbiological test, and 50 ⁇ L of each was left, and the degree of penetration after 30 seconds was observed. The series corresponding to the highest numbered test solution that did not mark or wet the sample was used as the oil repellency at AATCC118. Also, Emery 3004 (PAO (poly- ⁇ -olefin)) was prepared as a test solution, and 50 ⁇ L of the sample was allowed to stand on the surface of the sample with a micropipetter for microorganism test, and the degree of penetration after 30 seconds was observed.
  • PAO poly- ⁇ -olefin
  • test solution did not leave a mark or did not wet the sample, it was said to have oil repellency against PAO.
  • test solution was not completely absorbed by the sample, it was assumed to have oil repellency (non-penetration) with respect to PAO.
  • the particle collection efficiency test is performed before heat treatment (before the moisture resistance test) and after heating for 30 minutes at 40 ° C. and 95% RH (after the moisture resistance test), and the particles after the moisture resistance test for the particle collection efficiency before the moisture resistance test The ratio (%) of the collection efficiency was determined.
  • Evaluation particle Emery 3004 (PAO) in an equilibrium charged state Mode diameter 0.184 ⁇ m Ventilation speed: 5 cm / sec (6 L / min) Concentration: 100 mg / m 3 Efficiency calculation: Concentration evaluation before and after filter passage by light scattering concentration method
  • Glass-transition temperature The glass transition temperature of the particles is measured in accordance with JIS K 7121. Specifically, using a differential scanning calorimeter manufactured by TA Instruments under the conditions of a sample of 10 mg and a heating rate of 20 ° C./min. The measured midpoint glass transition temperature was taken as the glass transition temperature.
  • Polymers 2--7 In the polymer 1, a polymer was obtained in the same manner as the polymer 1 except that the amount of the substance added to water was changed. In polymer 5, ammonium perfluorohexanoate was added instead of perfluorohexanoic acid, and in polymer 6, sodium perfluorohexane was added instead of perfluorohexanoic acid. Table 1 shows the types and amounts of substances added to 200 parts by mass of water and the glass transition temperature of the obtained polymer.
  • Example 1 A polypropylene sheet having a basis weight of 30 g / m 2 , an average fiber diameter of 3 ⁇ m and a thickness of 0.25 mm obtained by the melt blown method is infiltrated with the emulsion of polymer 1 and dried at 80 ° C.
  • An electret filter was produced by carrying out a supporting treatment of 25 g / m 2 and performing electretization by performing direct current corona discharge in a state where the sample was left on the ground. The evaluation results of the obtained electret filter are shown in Table 2.
  • Example 2 to 6 Comparative Examples 1 to 3
  • a polymer was obtained in the same manner as in Example 1 except that the polymer emulsion to be permeated was changed.
  • the polymer 1 was not added but the filter was produced only with the polypropylene sheet used in Example 1.
  • Comparative Example 3 in place of Polymer 1, Unidyne (registered trademark) TG-5502 (Tg is 30 ° C. or lower) made by Daikin Industries, Ltd., which is a C 6 water- and oil-repellent agent, is added and supported.
  • a filter was produced in the same manner as in Example 1 except that the treatment was performed.
  • the evaluation results of the obtained electret filter are shown in Table 2.
  • the electret filter of the present invention can be widely used for filters for removing oil mist.
  • it can be widely used for dust and gas masks, household air purifiers, ventilation systems for buildings and vehicles, and protection of various devices.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Filtering Materials (AREA)
  • Electrostatic Separation (AREA)

Abstract

L'invention fournit un filtre électret qui peut être fabriqué à bas coût et selon une technique simple, et qui comporte des propriétés d'électret, des propriétés oléofuges et une résistance à un nuage d'huile. Plus précisément, l'invention concerne un filtre électret qui est équipé d'une couche de fibres constituée de fibres, et d'une couche oléofuge contenant un polymère à teneur en fluor en adhésion à la surface de la couche de fibres. Le polymère à teneur en fluor est obtenu à partir d'un composant monomère qui contient un monomère possédant un groupe alkyle à teneur en fluor de 7 atomes de carbone ou moins ou un groupe alkylène à teneur en fluor. La température de transition vitreuse ou le point de fusion dudit polymère à teneur en fluor, sont supérieurs ou égaux à 60°C.
PCT/JP2015/083521 2014-12-03 2015-11-30 Filtre électret WO2016088691A1 (fr)

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JP2018103109A (ja) * 2016-12-27 2018-07-05 東洋紡株式会社 エレクトレットフィルターおよびエレクトレットフィルターの製造方法
JP2018103108A (ja) * 2016-12-27 2018-07-05 東洋紡株式会社 エレクトレットフィルター

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JPH05214655A (ja) * 1992-01-30 1993-08-24 Daiwabo Create Kk エレクトレット繊維集合物
JPH06319923A (ja) * 1993-03-26 1994-11-22 Minnesota Mining & Mfg Co <3M> 耐油霧性エレクトレットフィルター媒体
WO2009104699A1 (fr) * 2008-02-22 2009-08-27 旭硝子株式会社 Electret et dispositif de conversion par induction électrostatique
JP2012001724A (ja) * 2011-07-26 2012-01-05 Daikin Industries Ltd 含フッ素シルセスキオキサン重合体を用いた表面処理剤
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JPS59181066U (ja) * 1983-05-20 1984-12-03 株式会社東芝 包装箱の構造
JPH05214655A (ja) * 1992-01-30 1993-08-24 Daiwabo Create Kk エレクトレット繊維集合物
JPH06319923A (ja) * 1993-03-26 1994-11-22 Minnesota Mining & Mfg Co <3M> 耐油霧性エレクトレットフィルター媒体
WO2009104699A1 (fr) * 2008-02-22 2009-08-27 旭硝子株式会社 Electret et dispositif de conversion par induction électrostatique
JP2012001724A (ja) * 2011-07-26 2012-01-05 Daikin Industries Ltd 含フッ素シルセスキオキサン重合体を用いた表面処理剤
JP2013034941A (ja) * 2011-08-08 2013-02-21 Toyobo Co Ltd 耐油性フィルター

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JP2018103109A (ja) * 2016-12-27 2018-07-05 東洋紡株式会社 エレクトレットフィルターおよびエレクトレットフィルターの製造方法
JP2018103108A (ja) * 2016-12-27 2018-07-05 東洋紡株式会社 エレクトレットフィルター

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