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
  • B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
  • B01D39/1607—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous
  • B01D39/1623—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of synthetic origin
• • 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
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
  • D04H3/08—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating
  • D04H3/10—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating with bonds between yarns or filaments made mechanically
  • D04H3/11—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating with bonds between yarns or filaments made mechanically by fluid jet
• • 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
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/20—Compounding polymers with additives, e.g. colouring
  • C08J3/201—Pre-melted polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/17—Amines; Quaternary ammonium compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/20—Carboxylic acid amides
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
  • D04H1/4282—Addition polymers
  • D04H1/4291—Olefin series
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
  • D04H1/4382—Stretched reticular film fibres; Composite fibres; Mixed fibres; Ultrafine fibres; Fibres for artificial leather
  • D04H1/43838—Ultrafine fibres, e.g. microfibres
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
  • D04H1/56—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving in association with fibre formation, e.g. immediately following extrusion of staple fibres
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
  • D04H3/005—Synthetic yarns or filaments
  • D04H3/007—Addition polymers
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
  • D04H3/08—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating
  • D04H3/16—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating with bonds between thermoplastic filaments produced in association with filament formation, e.g. immediately following extrusion
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G7/00—Capacitors in which the capacitance is varied by non-mechanical means; Processes of their manufacture
  • H01G7/02—Electrets, i.e. having a permanently-polarised dielectric
  • H01G7/021—Electrets, i.e. having a permanently-polarised dielectric having an organic dielectric
  • H01G7/023—Electrets, i.e. having a permanently-polarised dielectric having an organic dielectric of macromolecular compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/04—Additives and treatments of the filtering material
  • B01D2239/0435—Electret
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
  • B01D2239/0604—Arrangement of the fibres in the filtering material
  • B01D2239/0622—Melt-blown
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/10—Filtering material manufacturing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/12—Special parameters characterising the filtering material
  • B01D2239/1233—Fibre diameter
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
  • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
  • C08J2323/10—Homopolymers or copolymers of propene
  • C08J2323/12—Polypropene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K2201/00—Specific properties of additives
  • C08K2201/014—Additives containing two or more different additives of the same subgroup in C08K
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2321/00—Fibres made from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D10B2321/02—Fibres made from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds polyolefins
  • D10B2321/022—Fibres made from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds polyolefins polypropylene
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2505/00—Industrial
  • D10B2505/04—Filters
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G7/00—Capacitors in which the capacitance is varied by non-mechanical means; Processes of their manufacture
  • H01G7/02—Electrets, i.e. having a permanently-polarised dielectric

Definitions

• the present invention relates to an electret and an electret filter.
• Electrets are a group of materials that, through various manipulations of various dielectric materials, can maintain and utilize electrostatic forces without the need for continuous application of external energy. Electrets are used in microphones, sensors, generators, and various protection and isolation applications by utilizing electrostatic force against the outside.
• porous material itself is used in combination with separation and filtration applications to enhance functionality.
• filters using fibrous materials are widely used because they have the advantages of high porosity, long life, and low airflow resistance. Filters made of these fibrous materials trap particles on the fibers using mechanical trapping mechanisms such as blocking, diffusion, and inertial collision, but in a practical usage environment, the aerodynamic equivalent diameter of the trapped particles is 0.1. It is known that the filter collection efficiency reaches a minimum value when the diameter is about 1.0 ⁇ m, and to compensate for this weakness, an electret filter that utilizes the electrostatic attraction of electrets is used.
• an electrostatic charge to the fibrous material by a method of contacting or colliding a liquid with the fibrous material (liquid contact charging method) to form an electret.
• a method of contacting or colliding a liquid with the fibrous material liquid contact charging method
• an electret that achieves both cost and performance
• a fibrous material formed from a mixture of a resin whose main component is a polyolefin resin and a nitrogen-containing compound such as a hindered amine compound is brought into contact with a liquid such as water.
• Electrets with electrostatic charges are known.
• Patent Documents 1 to 3 disclose electret webs in which a fibrous material containing polyolefin resin as a main component is charged by a liquid contact charging method.
• US Pat. No. 5,000,303 discloses a nonwoven electret web comprising fibers made from a thermoplastic polymeric material, the thermoplastic polymeric material being formed into the fibers by treatment with a polymer and a polar liquid.
• a first additive (a) which traps the charge of a carboxylic acid having 29-50 carbon atoms and having one or two primary and/or secondary amino groups and in the aliphatic group
• a second additive comprising an organic amide derived from an aliphatic amine having 1-6 carbon atoms.
• Patent Document 2 discloses an electret material in which a reinforcing material is laminated on a carrier to which an electrostatic charge is applied and which supports fluorine. Further, Patent Document 3 discloses an electret web containing a thermoplastic resin and a predetermined charge-strengthening additive.
• the hindered amine compounds that have been widely added to conventionally known electrets have problems such as deterioration in quality due to off-odor and frying caused by thermal decomposition products. Additionally, due to heat treatment during processing, etc., the electrostatic force, or charge, that electret maintains may be attenuated, and antioxidants may be included to suppress this, but the suppression may not be sufficient. There is.
• the present invention provides a novel electret and an electret filter that achieve both productivity and charge stability that have not been achieved with conventionally known electrets.
• the present inventors discovered that by adding a combination of specific compounds to a polyolefin resin and charging it using a liquid contact method, an electret and an electret filter with excellent processability and charge stability can be obtained.
• the present invention has the following configuration. 1. An electret characterized by containing 90% by mass or more of a polyolefin resin, 0.1 to 5% by mass of a hindered phenol compound having an amide bond, and 0.1 to 5% by mass of a nitrogen-containing compound having a hydroxylamine structure. . 2. The electret as described in 1 above, which has a performance retention rate of 0.8 or more at 100°C. 3. 3. 3.
• the electret as described in 1 or 2 above which is a sheet-like product produced by a melt blowing method. 4.
• the electret according to any one of 1 to 3 above which is charged by contact with a liquid.
• the present invention it is possible to suppress the occurrence of shots due to an increase in spinning temperature when obtaining fineness and density of a nonwoven fabric. Further, by using an antioxidant having an amide bond rather than an ester bond found in many antioxidants, it is possible to suppress the decay of electrostatic charge due to heat. Therefore, according to the present invention, an electret and an electret filter with excellent productivity and charge stability can be obtained.
• the electret of the present invention uses a polyolefin resin that is hydrophobic and has high electrical resistance from the viewpoint of the degree of freedom in shape and the charge stability of the electret.
• polyolefin resins include homopolymers of olefins such as ethylene, propylene, butylene, hexene, octene, butadiene, isoprene, chloroprene, methyl-1-pentene, and cyclic olefins, and copolymers of two or more of the above olefins. can be mentioned.
• One type of polyolefin resin may be selected and used alone, or two or more types may be selected and used in combination.
• the polyolefin resin preferably contains at least one selected from polyethylene, polypropylene, and polymethylpentene, and more preferably contains polypropylene.
• the content of the polyolefin resin in 100 parts by mass of electret is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more. It is even more preferable that the amount is 97% by mass or more, particularly preferably 97% by mass or more.
• the upper limit of the content of the polyolefin resin is not particularly limited, and is, for example, 99.5% by mass or less, preferably 99% by mass or less.
• the degree of stereoregularity is preferably 85% or more, more preferably 90% or more, still more preferably 90% or more, particularly preferably 95% or more.
• isotactic or syndiotactic can be preferably used.
• the electret of the present invention contains one or more hindered phenol compounds having at least one amide bond in the molecule in the polyolefin resin.
• the hindered structure described above may include both hindered structures having steric hindrance groups on both sides of the phenolic hydroxyl group, and steric hindrance groups only on one side. Any single hindered one is preferable, and any of methyl, ethyl, propyl, butyl and each isomer can be preferably used. It is preferable that at least one phenol site exists at the end of the molecule, and it is also preferable that there be two or more phenol sites.
• the hindered phenol compound used in the present invention is characterized by having at least one amide bond in its molecular structure, and the bonding sites at both ends of the nitrogen atom and carbon atom of the amide bond are aliphatic carbon and Preferably, they are bonded.
• the number of amide bonds contained in the molecule may be two bisamides, three trisamides, or more. Both those having a straight chain structure and a branched structure can be preferably used.
• the number of carbon atoms contained between the amide groups is preferably in the range of 2 to 50, more preferably 2-30, still more preferably 2-20. If the number of carbon atoms is too small, it becomes difficult to handle due to decreased compatibility with the resin or a high melting point of the drug itself, and if it is too large, a large amount of compounding is required.
• the hindered phenol compound having an amide bond used in the present invention preferably has a melting point in the range of 60°C to 300°C, more preferably in the range of 80°C to 280°C, and most preferably in the range of 100°C to 250°C. It is °C. If the melting point is too low, stickiness and dissipation may easily occur, and if the melting point is too high, processability may be poor.
• the thermal decomposition temperature is preferably 150°C or higher, more preferably 200°C or higher, even more preferably 250°C or higher, and particularly preferably 300°C or higher. When the thermal decomposition temperature is low, there may be restrictions on molding conditions and use environment.
• the hindered phenol compound having an amide bond used in the present invention may be synthesized in-house, obtained as a reagent, or obtained as an industrial raw material, and may be a single compound or a mixture.
• N,N'-bis3-(3'5'di-t-butyl-4'-hydroxyphenyl)propionylhexamethylenediamine can be exemplified as one of the compounds available as a commercially available reagent or industrial raw material. .
• Irganox registered trademark
• 1098 manufactured by BASF Japan
• the content of the hindered phenol compound having an amide bond is preferably 0.1 to 5% by mass, and preferably 0.2 to 5% by mass relative to the polyolefin resin content of 90% by mass or more. It is more preferably 3% by mass, and particularly preferably 0.3 to 1.5% by mass.
• the proportion of hindered phenol with an amide bond contained in the polyolefin resin is Point.
• the electret contains resins other than polyolefins, they can be identified because they dissolve in solvents and acid-bases, or have different dyeing properties, and can be distinguished using methods such as DSC and NMR. Polyolefin resins can also be identified by quantitative methods. If the content is less than 0.1% by mass, the charge amount will be low and the filtration properties will be deteriorated, and if it is more than 5% by mass, the stability as an electret will be lost due to increased hydrophilicity.
• the electret in the present invention is characterized by containing a nitrogen-containing compound having a hydroxylamine structure in addition to the above-mentioned hindered phenol compound having an amide bond in the polyolefin resin.
• a hindered phenol compound having an amide bond and a nitrogen-containing compound having a hydroxylamine structure are clearly distinguished.
• N,N-dialkylhydroxylamine can be exemplified as one of the compounds available as a commercially available reagent or an industrial raw material. For example, it is sold as Irgastab (registered trademark) FS042 (manufactured by BASF Japan) as an antioxidant for polyolefin resins.
• the content of the nitrogen-containing compound having a hydroxylamine structure is preferably 0.1 to 5% by mass, and preferably 0.1 to 3% by mass relative to the polyolefin resin content of 90% by mass or more. It is more preferably 0.3% to 1.0% by mass, particularly preferably 0.3 to 1.0% by mass.
• the content of the nitrogen-containing compound having a hydroxylamine structure is preferably 0.1 to 5% by mass, and preferably 0.1 to 3% by mass relative to the polyolefin resin content of 90% by mass or more. It is more preferably 0.3% to 1.0% by mass, particularly preferably 0.3 to 1.0% by mass.
• two or more types of fibers are mixed in electret or two or more types of resin are mixed in one fiber, it refers to the proportion of nitrogen-containing compounds with a hydroxylamine structure contained in the polyolefin resin.
• the electret contains resins other than polyolefins, they can be identified because they dissolve in solvents and acid-bases, or have different dyeing properties, and can be distinguished using methods such as DSC and NMR. Polyolefin resins can also be identified by quantitative methods. If the content is less than 0.1% by mass, the charge amount will be low and the filtration properties will be deteriorated, and if it is more than 5% by mass, the stability as an electret will be lost due to increased hydrophilicity.
• the ratio of the hindered phenol compound having an amide bond to the nitrogen-containing compound having a hydroxylamine structure is not particularly limited as long as the desired properties can be obtained, but the mass ratio is preferably from 50:1 to 1:50.
• the mass ratio is preferably 20:1 to 1:20, still more preferably 10:1 to 1:10, particularly preferably 5:1 to 1:5.
• the content ratio of the hindered phenol compound having an amide bond and the nitrogen-containing compound having a hydroxylamine structure is not particularly limited as long as the desired properties can be obtained, but the content ratio of the two relative to the polyolefin resin material is from 0.2 to 0.2.
• the content is preferably 10% by weight, more preferably 0.3 to 5% by weight, even more preferably 0.4 to 4% by weight, and most preferably 0.5 to 3% by weight.
• the hindered phenol compound having an amide bond and the nitrogen-containing compound having a hydroxylamine structure used in the present invention need only be present at least on the surface of the electret molded body, and can be applied to the surface of the molded body by solution application, powder attachment, or polyolefin. They can be introduced by solution mixing, mixing during polymerization, melt mixing, etc.
• the melt mixing method is superior from the viewpoint of homogeneity and processability, and it is a method in which it is directly mixed with the resin during melt molding into the final shape, or it can be used as it is or diluted as a pre-made additive-containing resin compound. It can be used as
• the electret of the present invention can be used in any desired shape, such as fibrous materials, films, extruded materials, porous membranes, powders, and surface coating layers on other materials. can do. Among these, fibrous materials are particularly preferably used for filter applications.
• the above-mentioned fibrous material is preferably a fiber aggregate, and examples of the fiber aggregate include fibrous materials such as woven or knitted fabrics made of long or short fibers, nonwoven fabrics, cotton-like materials, or fibrous materials obtained from stretched films. Examples include things.
• a fiber aggregate is one that is recognized to have a fibrous form when the surface of the electret is observed using a device such as a scanning electron microscope or an optical microscope, and that at least some of the fibers constituting the fiber aggregate are Refers to a state in which the fibers are integrated by melting or entanglement between fibers.
• the fiber aggregate is preferably a nonwoven fabric.
• Methods for obtaining nonwoven fabrics include methods of forming single-component fibers, composite fibers such as core-sheath fibers and side-by-side fibers, and short fibers such as split fibers into sheets by carding, air-laid, wet paper-making methods, etc., and spunbond method using continuous fibers. It is possible to use conventionally known methods, such as forming a sheet using a melt-blowing method, an electrospinning method, or a force-spinning method.
• Nonwoven fabrics obtained by spunbond method, melt blown method, melt electrospinning method, or melt force spinning method are more preferable from the viewpoint of not requiring treatment of residual solvent or spinning oil adhering to the surface, and spunbond method or melt blown method. Particularly preferred are nonwoven fabrics obtained by this method.
• the average fiber diameter of the fibers used in the fibrous material is preferably 0.001 to 100 ⁇ m, more preferably 0.05 to 50 ⁇ m, and 0.001 to 100 ⁇ m, more preferably 0.05 to 50 ⁇ m. It is more preferably 1 to 30 ⁇ m, particularly preferably 0.3 to 25 ⁇ m, and most preferably 0.5 to 20 ⁇ m.
• the average fiber diameter of the fibers is thicker than 100 ⁇ m, it is difficult to obtain a practical collection efficiency, and the efficiency decreases significantly when the charge decays.
• the average fiber diameter of the fibers is smaller than 0.001 ⁇ m, it is difficult to produce a charged electret.
• the above-mentioned fineness is calculated by measuring the diameters of 50 fibers in the same field of view using a scanning electron microscope so that there is no overlap of the fibers, and taking the geometric mean.
• the fibrous material may be a homogeneous product made of a single manufacturing method and material, or a mixture made of two or more materials with different manufacturing methods, materials, and fiber diameters. It may be.
• the electret formation method in the present invention is not particularly limited as long as the desired characteristics can be obtained when using the electret, but when the electret of the present invention is a fibrous material, a method of contacting or colliding a liquid with the fibrous material ( The liquid contact charging method) is preferred, and an electret having high filtration properties can be obtained by the liquid contact charging method. More specifically, it is preferable to use a method in which the liquid is brought into contact with or collided with the fibrous material by a method such as suction, pressurization, or jetting.
• the liquid to be brought into contact or collided with in the liquid contact charging method is not particularly limited as long as the desired characteristics can be obtained, but from the viewpoint of handling and performance, water is preferable. Instead of water, a liquid obtained by adding a subcomponent (component other than water) to water may be used, and the conductivity and pH of the liquid can be adjusted by adjusting the type and amount of the subcomponent added.
• a subcomponent component other than water
• the liquid to be contacted or collided with in the liquid contact charging method preferably has a pH of 1 to 11, more preferably a pH of 3 to 9, and even more preferably a pH of 5 to 7. Further, the liquid that is contacted or collided with in the liquid contact charging method preferably has an electrical conductivity of 100 ⁇ S/cm or less, more preferably 10 ⁇ S/cm or less, and even more preferably 3 ⁇ S/cm or less.
• a filter using the electret of the present invention is also included in the scope of the present invention.
• the QF value described below is 1.0 mmAq-1 or more, preferably 1.1 mmAq-1 or more, more preferably 1.2 mmAq-1 or more, It is more preferably 1.3 mmAq-1 or more, and most preferably 1.4 mmAq-1 or more.
• an electret filter manufactured by a melt blowing method and having an average fiber diameter of 0.5 to 5 ⁇ m exceeds the above QF value. When it is less than 1.0 mmAq-1, particles are not sufficiently captured by the electret, resulting in insufficient performance as a filter.
• the QF value in this specification is calculated based on the ventilation resistance when aerating in the thickness direction of the filter at a wind speed of 10 cm/s and the number of particles counted in the particle size category of 0.3 to 0.5 ⁇ m using a laser particle counter. .
• the particle collection efficiency at a wind speed of 10 cm/s can be adjusted in various ways depending on the required characteristics, but it is preferably 50% or more, and preferably 70% or more. It is more preferably 90% or more, even more preferably 95% or more.
• the particle collection efficiency refers to the number of particles counted in the particle size category 0.3 to 0.5 ⁇ m by a laser particle counter before and after passing through the filter, when the air is ventilated in the thickness direction of the filter at a wind speed of 10 cm/s. Calculated based on.
• the ventilation resistance at a wind speed of 10 cm/s is preferably in the range of 0.05 to 50 mmAq, more preferably 0.2 to 30 mmAq, particularly preferably 0.5 to 50 mmAq. It is 20mmAq. If the ventilation resistance is too small, the performance as a filter will be insufficient, and if the ventilation resistance is too large, the advantages as an electret filter will be lost.
• the electret and electret filter of the present invention can be used in combination with other constituent members as necessary. That is, the electret of the present invention can be used in combination with a prefilter layer, a fiber protective layer, a reinforcing member, a functional fiber layer, and the like.
• Examples of the pre-filter layer and the fiber protection layer include spunbond nonwoven fabric, thermal bond nonwoven fabric, and foamed urethane fabric.
• Examples of the reinforcing member include thermal bond nonwoven fabric and various nets.
• Examples of the functional fiber layer include antibacterial, antiviral, and colored fiber layers for identification and design purposes.
• the electret of the present invention can be used in a wide range of applications.
• it can be suitably used for protection, ventilation, antifouling, waterproofing, etc., as dust masks, dustproof clothing, various air conditioning elements, air cleaners, cabin filters, and filters for protecting various devices.
• Ventilation resistance A sample punched to 72 mm ⁇ was attached to an adapter with an effective ventilation diameter of 50 mm ⁇ , and pipes with an inner diameter of 50 mm connected to a differential pressure gauge were connected above and below, and air was ventilated in the thickness direction of the sample at a speed of 10 cm/s. The pressure difference between the top and bottom of the sample in the absence of air flow was measured as ventilation resistance (pressure loss).
• Example 1 To 98.5% by mass of polypropylene homopolymer with a melt flow rate (MFR) of 1300 g/10 min, 1% by mass of Irganox (registered trademark) 1098 manufactured by BASF as a hindered phenol compound having an amide bond and a hydroxylamine structure. 0.5% by mass of N,N-dialkylhydroxylamine as a nitrogen-containing compound was spun using a melt blowing device at a nozzle temperature of 300°C and an air temperature of 280°C to obtain a fiber sheet with a basis weight of 30g/ m2 . Obtained.
• MFR melt flow rate
• the obtained fiber sheet was charged by passing water with an electrical conductivity of 0.7 ⁇ S/cm and a pH of 6.8 from the surface layer to the back surface, and then air-dried at 25° C. to obtain an electret sheet. .
• the properties as a filter were evaluated based on ventilation resistance and particle permeability.
• Example 1 was carried out in the same manner as in Example 1, except that only 1% by mass of Chimassorb (registered trademark) 944 manufactured by BASF, which is a hindered amine compound, was added to 99% by mass of polypropylene homopolymer with a melt flow rate (MFR) of 1300 g/10 min. An electret sheet of Comparative Example 2 was obtained.
• Chimassorb registered trademark 944 manufactured by BASF, which is a hindered amine compound
• MFR Melt flow rate
• ⁇ Comparative example 5 BASF Chimassorb (registered trademark) 944, a hindered amine compound, was added to 98.5% by mass of a polypropylene homopolymer with a melt flow rate (MFR) of 1300 g/10 min, and 1% by mass was added to BASF's Chimassorb® 944, a hindered phenol compound having an amide bond.
• An electret sheet of Comparative Example 5 was obtained in the same manner as in Example 1, except that 0.5% by mass of Irganox (registered trademark) 1098 manufactured by Co., Ltd. was added.
• Table 1 shows the evaluation measurement values of Example 1 and Comparative Examples 1 to 6.
• the table includes the natural logarithm (Ln) value of transmittance, the Ln (transmittance) ratio which is the numerical ratio with Example 1 (Example 1 is set as 1), and the QF value.
• the calculated QF ratio (Example 1 is set to 1), which is the numerical ratio of , is described.
• the table also shows the numerical ratio of the natural logarithm (Ln) value of the particle transmittance before heat treatment and after heat treatment at each temperature (the value before heat treatment is taken as 1). It also describes what has been done.
• Example 1 From the results of Example 1 and Comparative Examples 1 to 6, the electret containing the hindered phenol compound having an amide bond and the nitrogen-containing compound having a hydroxylamine structure of Example 1 has a QF ratio and a Ln (transmittance) ratio. It can be seen that it shows high collection performance. Further, since the average fiber diameter of Example 1 is equal to or larger than that of the comparative example, it can be seen that the amount of charge and the charge density are large. Further, Example 1 has superior trapping performance after heat treatment at 100° C. compared to Comparative Examples 3 and 4, which have the same trapping performance, which indicates that the charge stability is high.
• the electret of the present invention has excellent productivity and charge stability, and can be suitably used, for example, as a filter for dustproof clothing, dustproof masks, air cleaners, and the like.

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• 2023
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