WO2021199717A1 - Nonwoven fabric and method for manufacturing nonwoven fabric - Google Patents

Nonwoven fabric and method for manufacturing nonwoven fabric Download PDF

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Publication number
WO2021199717A1
WO2021199717A1 PCT/JP2021/005336 JP2021005336W WO2021199717A1 WO 2021199717 A1 WO2021199717 A1 WO 2021199717A1 JP 2021005336 W JP2021005336 W JP 2021005336W WO 2021199717 A1 WO2021199717 A1 WO 2021199717A1
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WO
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Prior art keywords
woven fabric
fiber
solution
collector
solvent
Prior art date
Application number
PCT/JP2021/005336
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French (fr)
Japanese (ja)
Inventor
洋亮 中川
金村　一秀
Original Assignee
富士フイルム株式会社
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Application filed by 富士フイルム株式会社 filed Critical 富士フイルム株式会社
Priority to CN202180025932.XA priority Critical patent/CN115349038A/en
Priority to JP2022511622A priority patent/JPWO2021199717A1/ja
Publication of WO2021199717A1 publication Critical patent/WO2021199717A1/en

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    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/04—Dry spinning methods
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F1/00—General methods for the manufacture of artificial filaments or the like
    • D01F1/02—Addition of substances to the spinning solution or to the melt
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F2/00—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F2/00—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof
    • D01F2/24—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from cellulose derivatives
    • D01F2/28—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from cellulose derivatives from organic cellulose esters or ethers, e.g. cellulose acetate
    • 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
    • D04H1/425—Cellulose series
    • D04H1/4258—Regenerated cellulose 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
    • 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
    • D04H1/70—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres
    • D04H1/72—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged
    • D04H1/728—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged by electro-spinning

Definitions

  • the present invention relates to a non-woven fabric and a non-woven fabric manufacturing method.
  • a non-woven fabric made of fiber is known.
  • Nonwoven fabrics are used in various applications such as filters.
  • an electric field spinning method is known.
  • the electrospinning method which is also called an electrospinning method, applies a voltage between a solution in which a fiber material is dissolved in a solvent and a collector, and ejects the solution to the collector to form a fiber on the surface of the collector. This is a method of collecting and obtaining a non-woven fabric.
  • the electric field spinning method since the fiber is charged, the electric field spinning method has a problem that it is difficult to increase the basis weight (weight per unit area) in addition to the problem that dust adheres. That is, since the fibers are charged at the same potential, the fibers repel each other. And this tendency becomes more remarkable as the collection progresses and the basis weight becomes larger. Therefore, the larger the basis weight, the more difficult it is to collect the fibers.
  • the present invention has been made in view of the above background, and an object of the present invention is to provide a non-woven fabric having a large basis weight and a non-woven fabric manufacturing method capable of producing such a non-woven fabric having a large basis weight.
  • the nonwoven fabric of the present invention includes fibers having an average wire diameter in the range of 10 nm or more and 2000 nm or less, has a void ratio of at least 90%, and has a basis weight of 120 g / m 2 or more and 2000 g / m. It is within the range of 2 or less.
  • the fiber may be made of a cellulosic polymer.
  • the cellulosic polymer may be cellulose acylate.
  • the fibers may have an entangled structure in which the fibers are entangled, and the entangled structure may be continuous from one surface side of the non-woven fabric to the other surface side.
  • the non-woven fabric manufacturing method of the present invention applies a voltage between a solution in which a fiber material is dissolved in a solvent and a collector, and ejects the solution from a nozzle to form a fiber.
  • the electrical conductivity of the solution is in the range of more than 2 mS / m and less than 50 mS / m, and is conductive with respect to the fibers collected on the surface of the collector. Adheres a conductive liquid having.
  • Electrolytes may be added to adjust the electrical conductivity of the solution.
  • the electrolyte may be lithium chloride, lithium bromide, or calcium chloride.
  • the solvent may be a mixture of a plurality of compounds.
  • the solvent may have a boiling point of 80 ° C. or lower.
  • the solvent may contain dichloromethane and methanol.
  • the fiber material may be a cellulosic polymer.
  • the cellulosic polymer may be cellulose acylate.
  • Cellulose acylate may be either cellulose acetate propionate or cellulose triacetate.
  • the electrical conductivity of the conductive liquid may be in the range of 0.1 mS / m or more and 50 mS / m or less.
  • the conductive liquid may be sprayed and adhered.
  • the non-woven fabric has an entangled structure in which fibers are entangled, and the entangled structure may be continuous from one surface side of the non-woven fabric to the other surface side.
  • the present invention it is possible to provide a non-woven fabric having a large basis weight and a non-woven fabric manufacturing method capable of producing such a non-woven fabric having a large basis weight.
  • the non-woven fabric 10 of the present embodiment shown in FIG. 1 is formed of a fiber 11.
  • the non-woven fabric 10 has an entangled structure in which the fibers 11 are entangled with each other, and the entangled structure is formed from one surface (hereinafter referred to as the first surface) 10A side in the thickness direction Z of the non-woven fabric 10 to the other surface (hereinafter referred to as the first surface). It is continuous up to the 10B side (referred to as 2 surfaces). That is, when a plurality of non-woven fabrics produced by spinning a plurality of times are stacked (laminated) to form one non-woven fabric, the above-mentioned entangled structure is interrupted between the layers of the non-woven fabrics (first surface 10A and second surface).
  • the entangled structure with 10B becomes intermittent).
  • the non-woven fabric 10 is different from the one in which a plurality of non-woven fabrics are laminated, and the entangled structure is continuous from the first surface 10A to the second surface 10B without interruption.
  • the non-woven fabric 10 has a structure in which the fiber 11 is further continuous on the lower side (second surface 10B side) of FIG. 1 in the thickness direction Z.
  • the non-woven fabric 10 may include the fiber 11, and may include other fibers made of different materials in addition to the fiber 11.
  • the fibers 11 are intertwined, and the non-woven fabric 10 is formed with a plurality of voids 14 as spatial regions defined by the fibers 11 as portions where air exists.
  • the plurality of voids 14 communicate with each other in the thickness direction Z of the non-woven fabric 10, pores are formed through the non-woven fabric 10 in the thickness direction Z.
  • the non-woven fabric 10 is used as a filter, for example, the pores function as holes in the filter.
  • some of the voids 14 do not form pores and exist as a non-penetrating space region in the thickness direction, for example, a space region closed by the fiber 11.
  • the volume ratio (hereinafter, porosity) of the void 14 in the non-woven fabric 10 is 90% or more (that is, at least 90%).
  • the porosity is more preferably in the range of 90% or more and 99% or less. It is more preferably in the range of 92% or more and 98% or less.
  • it can be used as a sound absorbing material and a heat insulating material because it exhibits excellent sound absorbing performance and heat insulating performance as compared with the case where the porosity is less than 90%.
  • the filter has a larger filtration treatment performance than the case where the porosity is less than 90%.
  • the filtration treatment performance means the amount of treatment per unit time and / or the sustainability of the state in which clogging is suppressed.
  • the porosity (unit:%) is such that the non-woven fabric 10 is weighed at W (unit is g / m 2 ), the thickness is H (unit is mm), and the specific gravity of the fiber 11 is ⁇ 1 (unit is kg / m 3 ). When doing so, it can be obtained by [1- ⁇ (W / 1000) / (H / 1000) ⁇ / ⁇ 1] ⁇ 100. Weighing W is cut out non-woven fabric 10 to 5 cm ⁇ 5 cm, the mass measured by an electronic balance (manufactured by Mettler-Toledo, Inc.), a value obtained by converting the measured value per 1 m 2.
  • the thickness H is measured by a non-contact laser displacement meter (LK-H025 manufactured by KEYENCE CORPORATION).
  • the wire diameter of the fiber 11 is formed to be substantially constant.
  • the average wire diameter (hereinafter referred to as the average wire diameter) is in the range of 10 nm or more and 2000 nm or less.
  • the average wire diameter is 10 nm or more, the detachment of the fiber piece is suppressed as compared with the case where the average wire diameter is less than 10 nm. Suppression of desorption of fiber pieces means that desorption of fiber pieces from the non-woven fabric 10 is suppressed, and suppression of desorption of fiber pieces leads to excellent durability of the non-woven fabric 10. ..
  • the non-woven fabric 10 is softer than the case where it is larger than 2000 nm even if the volume ratio of the air contained (hereinafter referred to as porosity) is the same. Further, since the average wire diameter is 2000 nm or less, the porosity of the non-woven fabric 10 is larger than that in the case of larger than 2000 nm even if the softness is about the same, and as a result, the sound absorbing material and the heat insulating material are used. When used as a filter, the sound absorption performance and heat insulation performance are improved, and when used as a filter, the amount of filtration treatment is increased.
  • the average wire diameter is more preferably in the range of 30 nm or more and 1500 nm or less, and further preferably in the range of 50 nm or more and 1000 nm or less.
  • the average wire diameter can be obtained by measuring the wire diameter of 100 fibers 11 from an image taken with a scanning electron microscope and calculating the average value.
  • the basis weight (weight per unit area) of the non-woven fabric 10 is in the range of 120 g / m 2 or more and 2000 g / m 2 or less, which is larger than the standard weight of the non-woven fabric.
  • the electrospinning method is used. Is preferable.
  • the larger the basis weight the larger the charge amount of the fibers 11 integrated in the collector 52 (see FIGS. 2 and 3) described later, and the fibers 11 repel each other in the vicinity of the collector 52.
  • the non-woven fabric 10 of the present invention is manufactured by devising a device for suppressing repulsion between fibers 11 in the vicinity of the collector 52 in the non-woven fabric manufacturing equipment 15 (see FIGS. 2 and 3) described later.
  • the non-woven fabric 10 has a small fiber diameter (average wire diameter of 2000 nm or less), a high porosity (porosity of 90% or more), and a large basis weight (120 g / m 2 or more).
  • the basis weight is preferably in the range of 150 g / m 2 or more and 1500 g / m 2 or less, and more preferably in the range of 200 g / m 2 or more and 1500 g / m 2 or less.
  • the non-woven fabric manufacturing equipment 15 of the present invention is for forming the fiber 11 and manufacturing the non-woven fabric 10 by using the electrospinning method, and is a solution preparing unit 23 and a non-woven fabric manufacturing unit. 24 and.
  • the solution preparation unit 23 is for preparing the solution 23a forming the fiber 11.
  • the solution preparation unit 23 dissolved the material of the fiber 11 (fiber material 16) with the solvent 17 and added, for example, an electrolyte 18 to adjust the electrical conductivity to a range of more than 2 mS / m and less than 50 mS / m.
  • a solution 23a is produced (prepared).
  • a resin can be used as the fiber material 16.
  • a resin polymer
  • the polymer it is preferable to use a polymer that can be made into a solution by dissolving it in a solvent 17, and more preferably a polymer that can be made into a solution by being dissolved in an organic solvent.
  • Cellulosic polymer it is preferable to use a cellulosic polymer.
  • cellulosic acylate is a cellulose ester in which some or all of the hydrogen atoms constituting the hydroxy group of cellulose are substituted with an acyl group.
  • the cellulose acylate is preferably any one of cellulose acetate propionate (CAP), cellulose triacetate (TAC), and cellulose diacetate (DAC).
  • the solvent 17 may be composed of one kind of compound or may be composed of two or more kinds of compounds. However, since the solvent 17 has a function of adjusting the evaporation rate in addition to the viewpoint of dissolving the fiber material 16, it is preferable that the solvent 17 is a mixture composed of two or more kinds of compounds from the viewpoint of adjusting the evaporation rate. .. Specific examples thereof include a mixture of dichloromethane (DCM) and methanol (Methanol), chloroform (CHCl 3 ), water, dimethylformamide (DMF) and the like.
  • DCM dichloromethane
  • Methanol methanol
  • chloroform CHCl 3
  • DMF dimethylformamide
  • the solvent 17 includes ethanol (EtOH), isopropanol, butanol, benzyl alcohol, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl formate, ethyl formate, hexane, cyclohexane, carbon tetrachloride, and benzene.
  • Xylene, N-methylpyrrolidone, diethyl ether, dioxane, 1-methoxy-2-propanol, toluene, acetone, tetrahydrofuran and the like can be used. These may be used alone or in combination of two or more.
  • the solvent 17 preferably has a boiling point of 80 ° C. or lower.
  • the solvent 17 having a low boiling point 80 ° C. or lower
  • the spinning amount per unit time is increased by using the solvent 17 having a low boiling point
  • the charging amount of the fiber 11 integrated in the collector 52 which will be described later, tends to be large, and it is difficult to increase the basis weight.
  • a device is provided to suppress repulsion between the fibers 11 in the vicinity of the collector 52. Therefore, in the present invention, the solvent 17 having a low boiling point can be used to shorten the drying time and increase the spinning amount per unit time while increasing the basis weight.
  • the boiling point of the compound having the largest mass ratio is regarded as the boiling point of the solvent 17.
  • the compound having the highest ratio is compound a and compound b
  • the boiling point of one of compound a and compound b having the higher boiling point is regarded as the boiling point of the solvent 17.
  • the solvent 17 is preferably an organic compound, that is, an organic solvent.
  • the electrolyte 18 is lithium chloride (LiCl), lithium bromide (LiBr), calcium chloride (CaCl 2 ) and the like.
  • the electrical conductivity of the solution 23a is adjusted to a range of more than 2 mS / m and less than 50 mS / m.
  • the electrical conductivity of the solution 23a is more preferably in the range of more than 5 mS / m and less than 40 mS / m, and further preferably in the range of more than 10 mS / m and less than 30 mS / m.
  • the basis weight can be increased. That is, since the solution 23a has electrical conductivity, the amount of charge of the fibers 11 in the vicinity of the collector 52, which will be described later, can be suppressed to be small and the repulsion between the fibers can be suppressed as compared with the case where the solution 23a does not have electrical leadability. .. As a result, the basis weight can be increased. Further, the diameter of the fiber 11 can be reduced by adding the electrolyte 18.
  • the solution 23a since the solution 23a has electrical conductivity, electric charges tend to collect in the solution 23a at the tip of the nozzle 25a, which will be described later, at the start of spinning or the like, and the solution 23a does not have electrical conductivity, as compared with the case where the solution 23a does not have electrical conductivity.
  • the solution 23a is attracted to the collector 52 side with a stronger force. This makes it possible to reduce the diameter of the fiber 11.
  • the solution 23a is produced by simultaneously mixing the fiber material 16, the solvent 17, and the electrolyte 18, but the present invention is not limited to this.
  • the solution 23a may be produced by adding the electrolyte 18 to the fiber material 16 dissolved in the solvent 17 (solution). Further, the solution 23a may be produced by dissolving the fiber material 16 with a solvent 17 to which the electrolyte 18 is added (solvent).
  • the fiber material 16 becomes highly viscous when made into a solution, and it takes time to dissolve the electrolyte 18. Therefore, it is preferable to generate the solution 23a by dissolving the fiber material 16 with a solvent 17 to which the electrolyte 18 is added (solvent).
  • the non-woven fabric manufacturing unit 24 includes a nozzle unit 25, an integrated unit 26, a power supply 27, and a sprayer 28.
  • the nozzle unit 25 is formed long in the width direction of the support 30 described later (see FIG. 2). Further, in the present embodiment, as described above, the nozzle units 25 long in the width direction of the support 30 are arranged side by side in the longitudinal direction of the support 30, and in the present embodiment, the three nozzle units 25 are arranged. (Three rows of nozzle units 25 are provided) (see FIG. 3). In these nozzle units 25, a plurality of nozzles 25a (three in the present embodiment) are arranged side by side along the longitudinal direction of the nozzle unit 25 (that is, the width direction of the support 30) (see FIG. 2).
  • the solution 23a prepared by the solution preparation unit 23 is supplied to each nozzle 25a, and the solution 23a is discharged from each nozzle 25a toward the integration unit 26.
  • the number of nozzle units 25 and the number of nozzles 25a provided in each nozzle unit 25 are not limited to this embodiment and can be changed as appropriate.
  • the collecting unit 26 has a collector 52, a support supply unit 57, and a support winding unit 58.
  • the collector 52 is for attracting the solution 23a discharged from the nozzle 25a and collecting the formed fibers 11 to obtain the non-woven fabric 10. In the present embodiment, the fibers 11 are placed on the support 30 described later. Collect.
  • the collector 52 is composed of an endless belt formed of a metal strip in an annular shape, is stretched over the rollers 61 and 62, and circulates and moves with the rotation of the rollers 61 and 62.
  • the support supply unit 57, the support winding unit 58, the rollers 61 and 62, the atomizer 28 described later, and the liquid supply unit 31 are not shown. ing. Further, in the present embodiment, the example of collecting the fiber 11 on the support 30 has been described, but the fiber 11 is collected directly on the collector 52 without going through the support 30 (abolished). May be. Further, in the present embodiment, an example in which the fiber 11 is collected on an endless belt stretched between two rollers, that is, an example in which the collector is an endless belt has been described, but the present invention is not limited thereto. .. For example, the fiber 11 may be collected on the peripheral surface of the rotating drum, that is, the collector may be the rotating drum.
  • a voltage is applied between the collector 52 and the nozzle unit 25 (nozzle 25a) by the power supply 27.
  • one of the collector 52 and the nozzle 25a is positively (+) charged, and the other is negatively ( ⁇ ) charged.
  • the solution 23a is attracted to the collector 52 side and ejected from the nozzle 25a toward the collector 52.
  • the collector 52 may be made of a material that is charged by applying a voltage from the power supply 27, and is made of, for example, stainless steel.
  • the nozzle 25a is charged with (+) and the collector 52 is charged with ( ⁇ ), but the polarities of the nozzle 25a and the collector 52 may be opposite. Further, one of the collector 52 and the nozzle 25a may be grounded to set the potential to 0.
  • the support supply unit 57 supplies, for example, a support 30 made of a strip-shaped aluminum sheet to the collector 52.
  • the support 30 moves with the movement of the collector 52 and passes below the nozzle unit 25.
  • the fibers 11 ejected from the nozzle 25a are sequentially collected on the support 30 to form the strip-shaped non-woven fabric 10.
  • the support 30 is peeled off from the non-woven fabric 10, and the support 30 is wound around the support winding portion 58.
  • the non-woven fabric 10 formed in this way has a thickness due to the entangled structure in which the fibers 11 are entangled with each other continuously from the first surface 10A to the second surface 10B without interruption, and also has a plurality of voids 14. (See Fig. 1).
  • a heating step may be provided to heat the non-woven fabric 10 together with the support 30, or the non-woven fabric 10 may be heated by itself after the support 30 is peeled off.
  • residual stress force accumulated in the fiber 11 at the time of collection and bending the fiber 11
  • a stretching step may be provided to stretch the non-woven fabric 10 together with the support 30, or the non-woven fabric 10 may be stretched by itself after the support 30 is peeled off.
  • the stretching may be performed in synchronization with the heating described above. By stretching, the fiber 11 can be straightened. Further, the pore diameter of the void 14 can be adjusted (enlarged).
  • a conductive liquid 31a having conductivity is supplied to the sprayer 28 from the liquid supply unit 31.
  • the sprayer 28 sprays and adheres the conductive liquid 31a supplied from the liquid supply unit 31 toward the fiber 11 collected by the collector 52.
  • adhering the conductive liquid 31a in this way the conductivity is improved in the vicinity of the collector 52 and the fiber 11 is statically eliminated (the charge amount of the fiber 11 can be reduced).
  • the repulsion between the fibers 11 can be suppressed and the basis weight can be increased.
  • the conductive liquid 31a can be produced, for example, by adding an electrolyte to pure water.
  • an electrolyte for example, sodium chloride, potassium chloride, calcium chloride, lithium chloride, magnesium chloride and the like can be used.
  • sodium chloride is used as the electrolyte, and a conductive liquid 31a having a conductivity (electrical conductivity) of 1.9 mS / m produced by adjusting to an aqueous solution of 0.001 wt% (weight concentration) is used. ing.
  • a conductive liquid 31a is uniformly sprayed on the entire spinning surface on which the fiber 11 is spun.
  • the conductive liquid 31a is sprayed with a basis weight equivalent to that of the fiber 11. That is, when 1 g of the fiber 11 is spun (collected) within a specific range, 1 g of the conductive liquid 31a is sprayed within this specific range.
  • the conductive liquid 31a it is preferable to spin the fiber 11 in a state where the conductive liquid 31a equivalent to the basis weight of the fiber 11 is attached to the fiber 11.
  • not all of the sprayed conductive liquid 31a adheres to the fiber 11, and a part of the conductive liquid 31a is scattered in a place different from the fiber 11.
  • the conductive liquid 31a adhering to the fiber 11 also decreases due to evaporation or the like with the passage of time. Therefore, it is preferable that the amount of the conductive liquid 31a sprayed is in the range of about the same as or about twice the basis weight of the fiber 11, that is, more conductive liquid 31a is sprayed than the basis weight of the fiber 11. By doing so, spinning can be performed in a state where the conductive liquid 31a having the same basis weight as the fiber 11 is attached to the fiber 11.
  • the electrical conductivity of the conductive liquid 31a is not limited to the above, but when the electrical conductivity is low, more conductive liquid 31a is used in order to suppress repulsion between the fibers 11 and increase the basis weight. Need to be sprayed. In this case, the distance between the fibers 11 becomes narrow due to the weight and tension of the conductive liquid 31a, and the porosity decreases. On the other hand, when the electrical conductivity is high, the spray amount of the conductive liquid 31a can be reduced and the decrease in the void ratio can be prevented, but on the other hand, it is difficult to uniformly adhere the conductive liquid 31a, and the conductive liquid 31a adheres.
  • the electrical conductivity of the conductive liquid 31a is preferably in the range of 0.1 mS / m or more and 50 mS / m or less, and more preferably in the range of 0.2 mS / m or more and 30 mS / m or less. It is preferably in the range of 1 mS / m or more and 20 mS / m or less.
  • the conductive liquid 31a In the production of the conductive liquid 31a, it is preferable to use pure water, and more preferably ultrapure water is used. This is because the smaller the number of impurities, the easier it is to adjust the electrical conductivity. However, since the conductive liquid 31a preferably does not dissolve the fiber 11, when the fiber 11 has a property of being soluble in water, the conductive liquid 31a is generated by using a solvent that does not dissolve the fiber 11. It is preferable to do so.
  • the conductive liquid 31a is sprayed and adhered to the fiber 11, but the conductive liquid 31a is adhered to the fiber 11 by various well-known methods such as spraying, showering, coating, and dipping. be able to.
  • the average wire diameter was small (the average wire diameter was 10 nm or more and 2000 nm or less), and the porosity was large (the porosity was 90% or more).
  • Comparative Example 1 produced without adhering the conductive liquid 31a, the basis weight was small. Further, in Comparative Example 2 in which the solution 23a was manufactured in a state where the electric conductivity of the solution 23a was small (with an electric conductivity of 2 mS / m or less) without adding the electrolyte 18, the average wire diameter was large and the porosity was large. Was also low. Further, in Comparative Example 3 in which the solution 23a was manufactured in a state where the electric conductivity is large (electrical conductivity is 50 mS / m or more), the nozzle 25a and the collector 52 are considered to be in the energized state, and the safety device of the manufacturing equipment is used. Was activated and spinning could not be performed.
  • Comparative Example 4 in which the electric conductivity of the solution 23a was small without adding the electrolyte 18 to the solution 23a and the solution 23a was manufactured without adhering the conductive liquid 31a, the average wire diameter was large. In addition, the porosity was low, and the texture was also small.

Abstract

Provided are a nonwoven fabric of a large basis weight, and a method for manufacturing the nonwoven fabric.　At a nonwoven fabric manufacturing facility (15), a fiber (11) formed by applying a voltage between a solution (23a) and a collector (52) and jetting out the solution (23a) through a nozzle (25a) is captured by the collector (52) to acquire a nonwoven fabric (10). The electrical conductivity of the solution (23a) is within a range of more than 2 mS/m but less than 50 mS/m. A conductive liquid (31a) is adhered to the fiber (11). The manufactured nonwoven fabric (10) has an average fiber diameter within a range of 10 nm-2000 nm, a porosity of 90% or higher, and a basis weight within a range of 120-2000 g/m2.<sp />

Description

不織布、不織布製造方法Non-woven fabric, non-woven fabric manufacturing method
　本発明は、不織布、不織布製造方法に関する。 The present invention relates to a non-woven fabric and a non-woven fabric manufacturing method.
　ファイバで形成された不織布が知られている。不織布は、フィルタなどの各種用途で用いられる。不織布を製造する方法としては、電界紡糸法が知られている。電界紡糸法は、エレクトロスピニング法などとも呼ばれ、溶媒にファイバ材が溶解している溶液とコレクタとの間に電圧を印加し、溶液をコレクタへ噴出することにより形成したファイバをコレクタの表面に捕集して不織布を得る方法である。 A non-woven fabric made of fiber is known. Nonwoven fabrics are used in various applications such as filters. As a method for producing a non-woven fabric, an electric field spinning method is known. The electrospinning method, which is also called an electrospinning method, applies a voltage between a solution in which a fiber material is dissolved in a solvent and a collector, and ejects the solution to the collector to form a fiber on the surface of the collector. This is a method of collecting and obtaining a non-woven fabric.
　電界紡糸法では、その製造方法に起因して、コレクタに捕集されたファイバが帯電しており、ダストが付着するといった問題があった。このような帯電によるダストの付着を防止するために、下記特許文献１では、不織布の除電を行っている。 In the electric field spinning method, there was a problem that the fibers collected in the collector were charged and dust adhered due to the manufacturing method. In order to prevent the adhesion of dust due to such charging, in Patent Document 1 below, the non-woven fabric is statically eliminated.
特開２０１７－０５３０６４号公報Japanese Unexamined Patent Publication No. 2017-053064
　上述のようにファイバが帯電していることで、電界紡糸法では、ダストが付着するといった問題とは別に、目付（単位面積あたりの重さ）を大きくすることが難しいといった問題もあった。つまり、ファイバは同電位に帯電するため、ファイバ同士が反発しあう。そして、この傾向は、捕集が進んで目付が大きくなるほど顕著となる。このため、目付が大きくなるほどファイバを捕集することが難しくなる。 As described above, since the fiber is charged, the electric field spinning method has a problem that it is difficult to increase the basis weight (weight per unit area) in addition to the problem that dust adheres. That is, since the fibers are charged at the same potential, the fibers repel each other. And this tendency becomes more remarkable as the collection progresses and the basis weight becomes larger. Therefore, the larger the basis weight, the more difficult it is to collect the fibers.
　このような問題は、上記特許文献１のように除電を行うことにより、緩和することは可能であるが、従来の除電方法で除電するだけでは減少できる帯電量に限界があり、目付を大きくするには不十分であった。 Such a problem can be alleviated by static elimination as in Patent Document 1, but there is a limit to the amount of charge that can be reduced only by static elimination by the conventional static elimination method, and the basis weight is increased. Was not enough.
　本発明は、上記背景を鑑みてなされたものであり、目付の大きな不織布、及び、このような目付の大きな不織布を製造可能な不織布製造方法を提供することを目的としている。 The present invention has been made in view of the above background, and an object of the present invention is to provide a non-woven fabric having a large basis weight and a non-woven fabric manufacturing method capable of producing such a non-woven fabric having a large basis weight.
　上記課題を解決するために、本発明の不織布は、平均線径が１０ｎｍ以上２０００ｎｍ以下の範囲内であるファイバを備え、空隙率が少なくとも９０％であり、目付が１２０ｇ／ｍ２　以上２０００ｇ／ｍ２　以下の範囲内である。 In order to solve the above problems, the nonwoven fabric of the present invention includes fibers having an average wire diameter in the range of 10 nm or more and 2000 nm or less, has a void ratio of at least 90%, and has a basis weight of 120 g / m 2 or more and 2000 g / m. It is within the range of 2 or less.
　ファイバは、セルロース系ポリマーで形成されたものでもよい。 The fiber may be made of a cellulosic polymer.
　セルロース系ポリマーは、セルロースアシレートであってもよい。 The cellulosic polymer may be cellulose acylate.
　ファイバが絡み合う絡み合い構造を有し、絡み合い構造が、不織布の一方の表面側から他方の表面側まで連続していてもよい。 The fibers may have an entangled structure in which the fibers are entangled, and the entangled structure may be continuous from one surface side of the non-woven fabric to the other surface side.
　また、上記課題を解決するために、本発明の不織布製造方法は、溶媒にファイバ材が溶解している溶液とコレクタとの間に電圧を印加し、溶液をノズルから噴出することにより形成したファイバを、コレクタの表面に捕集する不織布製造方法において、溶液の電気伝導度が２ｍＳ／ｍより大きく、５０ｍＳ／ｍ未満の範囲内であり、コレクタの表面に捕集されたファイバに対して導電性を有する導電性液体を付着させる。 Further, in order to solve the above problems, the non-woven fabric manufacturing method of the present invention applies a voltage between a solution in which a fiber material is dissolved in a solvent and a collector, and ejects the solution from a nozzle to form a fiber. In the method for producing a non-woven fabric that collects the liquid on the surface of the collector, the electrical conductivity of the solution is in the range of more than 2 mS / m and less than 50 mS / m, and is conductive with respect to the fibers collected on the surface of the collector. Adheres a conductive liquid having.
　電解質を添加して、溶液の電気伝導度を調整してもよい。 Electrolytes may be added to adjust the electrical conductivity of the solution.
　電解質は、塩化リチウム、臭化リチウム、塩化カルシウムのいずれかであってもよい。 The electrolyte may be lithium chloride, lithium bromide, or calcium chloride.
　溶媒は、複数の化合物の混合物であってもよい。 The solvent may be a mixture of a plurality of compounds.
　溶媒は、沸点８０℃以下であってもよい。 The solvent may have a boiling point of 80 ° C. or lower.
　溶媒は、ジクロロメタンとメタノールとを含有していてもよい。 The solvent may contain dichloromethane and methanol.
　ファイバ材は、セルロース系ポリマーであってもよい。 The fiber material may be a cellulosic polymer.
　セルロース系ポリマーは、セルロースアシレートであってもよい。 The cellulosic polymer may be cellulose acylate.
　セルロースアシレートは、セルロースアセテートプロピオネート、セルローストリアセテートのいずれかであってもよい。 Cellulose acylate may be either cellulose acetate propionate or cellulose triacetate.
　導電性液体の電気伝導度が０．１ｍＳ／ｍ以上、５０ｍＳ／ｍ以下の範囲内であってもよい。 The electrical conductivity of the conductive liquid may be in the range of 0.1 mS / m or more and 50 mS / m or less.
　導電性液体を噴霧して付着させてもよい。 The conductive liquid may be sprayed and adhered.
　不織布は、ファイバが絡み合う絡み合い構造を有し、絡み合い構造が、不織布の一方の表面側から他方の表面側まで連続していてもよい。 The non-woven fabric has an entangled structure in which fibers are entangled, and the entangled structure may be continuous from one surface side of the non-woven fabric to the other surface side.
　本発明によれば、目付の大きな不織布、及び、このような目付の大きな不織布を製造可能な不織布製造方法を提供できる。 According to the present invention, it is possible to provide a non-woven fabric having a large basis weight and a non-woven fabric manufacturing method capable of producing such a non-woven fabric having a large basis weight.
不織布の第１表面側の一部を示す説明図である。It is explanatory drawing which shows a part of the 1st surface side of a non-woven fabric. 不織布製造設備の概略図である。It is the schematic of the non-woven fabric manufacturing equipment. 不織布製造設備の概略図である。It is the schematic of the non-woven fabric manufacturing equipment.
　図１に示す本実施形態の不織布１０は、ファイバ１１で形成されている。不織布１０は、ファイバ１１同士が絡み合う絡み合い構造を有し、この絡み合い構造が、不織布１０の厚み方向Ｚにおいて一方の表面（以下、第１表面と称する）１０Ａ側から、他方の表面（以下、第２表面と称する）１０Ｂ側まで連続している。つまり、複数回の紡糸により製造された複数枚の不織布を重ねて（積層して）１枚の不織布とした場合、不織布同士の層間で前述の絡み合い構造が途切れる（第１表面１０Ａと第２表面１０Ｂとの間で絡み合い構造が断続的となる）。これに対し、不織布１０は、複数枚の不織布を積層したものとは異なり、第１表面１０Ａから第２表面１０Ｂまで絡み合い構造が途切れることなく連続している。 The non-woven fabric 10 of the present embodiment shown in FIG. 1 is formed of a fiber 11. The non-woven fabric 10 has an entangled structure in which the fibers 11 are entangled with each other, and the entangled structure is formed from one surface (hereinafter referred to as the first surface) 10A side in the thickness direction Z of the non-woven fabric 10 to the other surface (hereinafter referred to as the first surface). It is continuous up to the 10B side (referred to as 2 surfaces). That is, when a plurality of non-woven fabrics produced by spinning a plurality of times are stacked (laminated) to form one non-woven fabric, the above-mentioned entangled structure is interrupted between the layers of the non-woven fabrics (first surface 10A and second surface). The entangled structure with 10B becomes intermittent). On the other hand, the non-woven fabric 10 is different from the one in which a plurality of non-woven fabrics are laminated, and the entangled structure is continuous from the first surface 10A to the second surface 10B without interruption.
　なお、図１では、図の煩雑化を避けるために、不織布１０の第１表面１０Ａ側の一部のみを描き、第２表面１０Ｂ側については図示を省略している。したがって、不織布１０は、ファイバ１１が、厚み方向Ｚにおける図１の下側（第２表面１０Ｂ側）に、さらに連続した構造となっている。なお、不織布１０は、ファイバ１１を含んでいればよく、ファイバ１１に加えて、素材が異なる他のファイバを備えてもよい。 Note that in FIG. 1, in order to avoid complication of the drawing, only a part of the first surface 10A side of the non-woven fabric 10 is drawn, and the illustration of the second surface 10B side is omitted. Therefore, the non-woven fabric 10 has a structure in which the fiber 11 is further continuous on the lower side (second surface 10B side) of FIG. 1 in the thickness direction Z. The non-woven fabric 10 may include the fiber 11, and may include other fibers made of different materials in addition to the fiber 11.
　前述のように、ファイバ１１は絡み合っており、不織布１０には、ファイバ１１によって画定された空間領域としての空隙１４が、空気が存在する部分として複数形成されている。複数の空隙１４は、不織布１０の厚み方向Ｚにおいて連通している場合には、不織布１０の厚み方向Ｚに貫通した空孔を形成する。この空孔は、不織布１０を例えばフィルタに利用した場合には、フィルタの孔として機能する。また、空隙１４の中には、空孔を形成せずに、厚み方向で非貫通、例えばファイバ１１によって閉じられた空間領域として存在しているものもある。 As described above, the fibers 11 are intertwined, and the non-woven fabric 10 is formed with a plurality of voids 14 as spatial regions defined by the fibers 11 as portions where air exists. When the plurality of voids 14 communicate with each other in the thickness direction Z of the non-woven fabric 10, pores are formed through the non-woven fabric 10 in the thickness direction Z. When the non-woven fabric 10 is used as a filter, for example, the pores function as holes in the filter. Further, some of the voids 14 do not form pores and exist as a non-penetrating space region in the thickness direction, for example, a space region closed by the fiber 11.
　不織布１０における空隙１４の体積割合（以下、空隙率）は、９０％以上（すなわち、少なくとも９０％）である。なお、空隙率は９０％以上９９％以下の範囲内であることがより好ましく。９２％以上９８％以下の範囲内であることがさらに好ましい。このように空隙率を大きくすること、すなわち、内部に多量の空気を含ませることで用途に広がりをもたせることができる。例えば、９０％未満の空隙率である場合に比べて優れた吸音性能及び断熱性能を示すから、吸音材及び断熱材として利用できる。また、９０％未満の空隙率である場合に比べて、フィルタにした場合には大きなろ過処理性能を示す。ろ過処理性能とは、単位時間あたりの処理量、及び／または、目詰まりが抑制された状態の持続性などを意味する。 The volume ratio (hereinafter, porosity) of the void 14 in the non-woven fabric 10 is 90% or more (that is, at least 90%). The porosity is more preferably in the range of 90% or more and 99% or less. It is more preferably in the range of 92% or more and 98% or less. By increasing the porosity in this way, that is, by including a large amount of air inside, it is possible to expand the range of applications. For example, it can be used as a sound absorbing material and a heat insulating material because it exhibits excellent sound absorbing performance and heat insulating performance as compared with the case where the porosity is less than 90%. Further, the filter has a larger filtration treatment performance than the case where the porosity is less than 90%. The filtration treatment performance means the amount of treatment per unit time and / or the sustainability of the state in which clogging is suppressed.
　空隙率（単位は％）は、不織布１０の秤量をＷ（単位はｇ／ｍ２）とし、厚みをＨ（単位はｍｍ）とし、ファイバ１１の比重をρ１（単位はｋｇ／ｍ３）とするときに、［１－｛（Ｗ／１０００）／（Ｈ／１０００）｝／ρ１］×１００で求めることができる。秤量Ｗは、不織布１０を５ｃｍ×５ｃｍに切り出し、質量を電子天秤（メトラー・トレド株式会社製）で測定し、その測定値を１ｍ２あたりに換算した値を用いる。厚みＨは、本例では、非接触レーザー変位計（キーエンス株式会社製ＬＫ－Ｈ０２５）で測定している。 The porosity (unit:%) is such that the non-woven fabric 10 is weighed at W (unit is g / m 2 ), the thickness is H (unit is mm), and the specific gravity of the fiber 11 is ρ1 (unit is kg / m 3 ). When doing so, it can be obtained by [1-{(W / 1000) / (H / 1000)} / ρ1] × 100. Weighing W is cut out non-woven fabric 10 to 5 cm × 5 cm, the mass measured by an electronic balance (manufactured by Mettler-Toledo, Inc.), a value obtained by converting the measured value per 1 m 2. In this example, the thickness H is measured by a non-contact laser displacement meter (LK-H025 manufactured by KEYENCE CORPORATION).
　ファイバ１１は、線径が概ね一定に形成されている。線径の平均（以下、平均線径と称する）は、１０ｎｍ以上２０００ｎｍ以下の範囲内である。平均線径が１０ｎｍ以上であることにより、１０ｎｍ未満の場合と比べて、ファイバ片の脱離が抑制される。ファイバ片の脱離の抑制とは、不織布１０からのファイバ片の脱離が抑制されることを意味し、ファイバ片の脱離が抑制されていることは不織布１０としての優れた耐久性につながる。平均線径が２０００ｎｍ以下であることにより、２０００ｎｍよりも大きい場合に比べて、不織布１０は、含んでいる空気の体積割合（以下、空隙率と称する）が同じであっても、より柔らかくなる。また、平均線径が２０００ｎｍ以下であることにより、２０００ｎｍよりも大きい場合に比べて、不織布１０は柔らかさが同程度であっても、空隙率がより大きくなり、その結果、吸音材、断熱材として用いた場合の吸音性能、断熱性能が高くなり、また、フィルタに利用した場合のろ過処理量が高くなる。 The wire diameter of the fiber 11 is formed to be substantially constant. The average wire diameter (hereinafter referred to as the average wire diameter) is in the range of 10 nm or more and 2000 nm or less. When the average wire diameter is 10 nm or more, the detachment of the fiber piece is suppressed as compared with the case where the average wire diameter is less than 10 nm. Suppression of desorption of fiber pieces means that desorption of fiber pieces from the non-woven fabric 10 is suppressed, and suppression of desorption of fiber pieces leads to excellent durability of the non-woven fabric 10. .. Since the average wire diameter is 2000 nm or less, the non-woven fabric 10 is softer than the case where it is larger than 2000 nm even if the volume ratio of the air contained (hereinafter referred to as porosity) is the same. Further, since the average wire diameter is 2000 nm or less, the porosity of the non-woven fabric 10 is larger than that in the case of larger than 2000 nm even if the softness is about the same, and as a result, the sound absorbing material and the heat insulating material are used. When used as a filter, the sound absorption performance and heat insulation performance are improved, and when used as a filter, the amount of filtration treatment is increased.
　なお、平均線径は、３０ｎｍ以上１５００ｎｍ以下の範囲内であることがより好ましく、５０ｎｍ以上１０００ｎｍ以下の範囲内であることがさらに好ましい。平均線径は、走査型電子顕微鏡で撮影した画像から１００本のファイバ１１の線径を測定し、平均値を算出することにより求めることができる。 The average wire diameter is more preferably in the range of 30 nm or more and 1500 nm or less, and further preferably in the range of 50 nm or more and 1000 nm or less. The average wire diameter can be obtained by measuring the wire diameter of 100 fibers 11 from an image taken with a scanning electron microscope and calculating the average value.
　不織布１０の目付（単位面積あたりの重さ）は、１２０ｇ／ｍ２　以上２０００ｇ／ｍ２　以下の範囲内であり、標準的な不織布の目付よりも大きくされている。一般に、本実施形態のように繊維径が細く（平均線径が２０００ｎｍ以下であり）、かつ、空隙率の高い（空隙率９０％以上である）不織布を製造する場合、電界紡糸法が用いることが好適である。しかしながら、電界紡糸法では、目付が大きくなるほど、後述するコレクタ５２（図２、図３参照）に集積されたファイバ１１の帯電量が大きくなり、コレクタ５２の近傍においてはファイバ１１同士が反発し合うため、従来は本発明のように目付を大きくする（１２０ｇ／ｍ２　以上とする）ことが難しかった。そこで、本発明の不織布１０は、後述する不織布製造設備１５（図２、図３参照）において、コレクタ５２の近傍におけるファイバ１１同士の反発を抑える工夫を施して製造している。これにより、不織布１０は、繊維径が細く（平均線径が２０００ｎｍ以下であり）、空隙率が高く（空隙率９０％以上であり）、さらには、目付が大きい（１２０ｇ／ｍ２　以上）といった、従来では製造することのできないものとなっている。なお、目付は、１５０ｇ／ｍ２　以上１５００ｇ／ｍ２　以下の範囲内であることが好ましく、２００ｇ／ｍ２　以上１５００ｇ／ｍ２　以下の範囲内であることがさらに好ましい。 The basis weight (weight per unit area) of the non-woven fabric 10 is in the range of 120 g / m 2 or more and 2000 g / m 2 or less, which is larger than the standard weight of the non-woven fabric. Generally, when producing a nonwoven fabric having a small fiber diameter (average wire diameter of 2000 nm or less) and a high porosity (porosity of 90% or more) as in the present embodiment, the electrospinning method is used. Is preferable. However, in the electrospinning method, the larger the basis weight, the larger the charge amount of the fibers 11 integrated in the collector 52 (see FIGS. 2 and 3) described later, and the fibers 11 repel each other in the vicinity of the collector 52. Therefore, conventionally, it has been difficult to increase the basis weight (120 g / m 2 or more) as in the present invention. Therefore, the non-woven fabric 10 of the present invention is manufactured by devising a device for suppressing repulsion between fibers 11 in the vicinity of the collector 52 in the non-woven fabric manufacturing equipment 15 (see FIGS. 2 and 3) described later. As a result, the non-woven fabric 10 has a small fiber diameter (average wire diameter of 2000 nm or less), a high porosity (porosity of 90% or more), and a large basis weight (120 g / m 2 or more). , It has become something that cannot be manufactured in the past. The basis weight is preferably in the range of 150 g / m 2 or more and 1500 g / m 2 or less, and more preferably in the range of 200 g / m 2 or more and 1500 g / m 2 or less.
　図２、図３に示すように、本発明の不織布製造設備１５は、電界紡糸法を用いてファイバ１１の形成及び不織布１０の製造をするためのものであり、溶液調製部２３と不織布製造部２４とを備える。溶液調製部２３は、ファイバ１１を形成する溶液２３ａを調製するためのものである。溶液調製部２３は、ファイバ１１の素材（ファイバ材１６）を溶媒１７により溶解するとともに、例えば電解質１８を添加することにより、電気伝導度を２ｍＳ／ｍより大きく５０ｍＳ／ｍ未満の範囲に調整した溶液２３ａを生成（調製）する。 As shown in FIGS. 2 and 3, the non-woven fabric manufacturing equipment 15 of the present invention is for forming the fiber 11 and manufacturing the non-woven fabric 10 by using the electrospinning method, and is a solution preparing unit 23 and a non-woven fabric manufacturing unit. 24 and. The solution preparation unit 23 is for preparing the solution 23a forming the fiber 11. The solution preparation unit 23 dissolved the material of the fiber 11 (fiber material 16) with the solvent 17 and added, for example, an electrolyte 18 to adjust the electrical conductivity to a range of more than 2 mS / m and less than 50 mS / m. A solution 23a is produced (prepared).
　ファイバ材１６としては、樹脂（ポリマー）を用いることができる。ポリマーとしては、溶媒１７に溶解することにより溶液にできるポリマーを用いることが好ましく、有機溶媒に溶解することにより溶液にできるポリマーであることがより好ましい。具体的には、セルロース系ポリマー、シクロオレフィンポリマー（ＣＯＰなど）、ポリメチルメタクリレート（ＰＭＭＡ）、ポリエステル、ポリウレタン、ポリエチレン（ＰＥ）、ポリプロピレン、エラストマ、ポリ乳酸（ＰＬＡ）、ポリスチレン、ポリカーボネイト、ポリアクリルニトリル（ＰＡＮ）、アクリル樹脂、ポリビニルアルコール（ＰＶＡ）、ゼラチン、ポリイミド、ポリエーテルエーテルケトン（ＰＥＥＫ）、液晶性ポリマー（ＬＣＰ）、フッ素系樹脂などが挙げられる。 As the fiber material 16, a resin (polymer) can be used. As the polymer, it is preferable to use a polymer that can be made into a solution by dissolving it in a solvent 17, and more preferably a polymer that can be made into a solution by being dissolved in an organic solvent. Specifically, cellulose-based polymers, cycloolefin polymers (COP, etc.), polymethylmethacrylate (PMMA), polyester, polyurethane, polyethylene (PE), polypropylene, elastoma, polylactic acid (PLA), polystyrene, polycarbonate, polyacrylic nitrile. (PAN), acrylic resin, polyvinyl alcohol (PVA), gelatin, polyimide, polyether ether ketone (PEEK), liquid crystal polymer (LCP), fluororesin and the like can be mentioned.
　なお、上記のポリマーのなかでも、セルロース系ポリマーを用いることが好ましい。さらに、セルロース系ポリマーを用いる場合、セルロースアシレートを用いることが好ましい。セルロースアシレートは、セルロースのヒドロキシ基を構成する水素原子の一部または全部がアシル基で置換されているセルロースエステルである。またセルロースアシレートは、セルロースアセテートプロピオネート（ＣＡＰ）、セルローストリアセテート（ＴＡＣ）、セルロースジアセテート（ＤＡＣ）のいずれかであることが好ましい。 Among the above polymers, it is preferable to use a cellulosic polymer. Furthermore, when a cellulosic polymer is used, it is preferable to use cellulosic acylate. Cellulose acylate is a cellulose ester in which some or all of the hydrogen atoms constituting the hydroxy group of cellulose are substituted with an acyl group. The cellulose acylate is preferably any one of cellulose acetate propionate (CAP), cellulose triacetate (TAC), and cellulose diacetate (DAC).
　溶媒１７は、１種類の化合物で構成されていてもよいし、２種類以上の化合物で構成されていてもよい。ただし、溶媒１７は、ファイバ材１６を溶解する観点の他に、蒸発速度を調整する機能をもつから、蒸発速度を調整する観点では、２種類以上の化合物で構成された混合物である方が好ましい。具体的には、ジクロロメタン（ＤＣＭ）とメタノール（ＭｅＯＨ）の混合物、クロロホルム（ＣＨＣｌ３　）、水、ジメチルホルムアミド（ＤＭＦ）などが挙げられる。また、溶媒１７としては、エタノール（ＥｔＯＨ）、イソプロパノール、ブタノール、ベンジルアルコール、メチルエチルケトン、シクロヘキサノン、メチルアセテート、エチルアセテート、プロピルアセテート、ブチルアセテート、ギ酸メチル、ギ酸エチル、ヘキサン、シクロヘキサン、四塩化炭素、ベンゼン、キシレン、Ｎ－メチルピロリドン、ジエチルエーテル、ジオキサン、１－メトキシ－２－プロパノール、トルエン、アセトン、テトラヒドロフランなどを用いることができる。これらは、単独で使用してもよいし、２種類以上を混合して使用してもよい。 The solvent 17 may be composed of one kind of compound or may be composed of two or more kinds of compounds. However, since the solvent 17 has a function of adjusting the evaporation rate in addition to the viewpoint of dissolving the fiber material 16, it is preferable that the solvent 17 is a mixture composed of two or more kinds of compounds from the viewpoint of adjusting the evaporation rate. .. Specific examples thereof include a mixture of dichloromethane (DCM) and methanol (Methanol), chloroform (CHCl 3 ), water, dimethylformamide (DMF) and the like. The solvent 17 includes ethanol (EtOH), isopropanol, butanol, benzyl alcohol, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl formate, ethyl formate, hexane, cyclohexane, carbon tetrachloride, and benzene. , Xylene, N-methylpyrrolidone, diethyl ether, dioxane, 1-methoxy-2-propanol, toluene, acetone, tetrahydrofuran and the like can be used. These may be used alone or in combination of two or more.
　溶媒１７は、沸点が８０℃以下であることが好ましい。このように沸点の低い（８０℃以下の）溶媒１７を用いることで、蒸発速度を速めて乾燥時間を短縮することが可能であり、単位時間あたりの紡糸量（目付量）を増加できる。一方、沸点の低い溶媒１７を用いて単位時間あたりの紡糸量を増加させた場合、後述するコレクタ５２に集積されたファイバ１１の帯電量も大きくなる傾向にあり、目付を大きくすることが難しいが、本発明では、前述のようにコレクタ５２の近傍におけるファイバ１１同士の反発を抑える工夫を施している。このため、本発明では、沸点の低い溶媒１７を用いて乾燥時間を短縮し単位時間あたりの紡糸量を増加させながら目付を大きくできる。 The solvent 17 preferably has a boiling point of 80 ° C. or lower. By using the solvent 17 having a low boiling point (80 ° C. or lower) as described above, it is possible to accelerate the evaporation rate and shorten the drying time, and it is possible to increase the spinning amount (weighting amount) per unit time. On the other hand, when the spinning amount per unit time is increased by using the solvent 17 having a low boiling point, the charging amount of the fiber 11 integrated in the collector 52, which will be described later, tends to be large, and it is difficult to increase the basis weight. In the present invention, as described above, a device is provided to suppress repulsion between the fibers 11 in the vicinity of the collector 52. Therefore, in the present invention, the solvent 17 having a low boiling point can be used to shorten the drying time and increase the spinning amount per unit time while increasing the basis weight.
　なお、溶媒１７が複数の化合物の混合物である場合には、質量割合が最も多い化合物の沸点を、溶媒１７の沸点としてみなす。また、溶媒１７が３種以上の化合物の混合物であり、質量割合が最も多い化合物が複数ある場合には、それらのうち沸点が最も高い化合物の沸点を溶媒１７の沸点とみなす。例えば、溶媒１７が化合物ａと化合物ｂと化合物ｃとの混合物であり、（化合物ａの質量）：（化合物ｂの質量）：（化合物ｃの質量）＝４０：４０：２０というように、質量割合が最も多い化合物が化合物ａと化合物ｂとの２つである場合には、化合物ａと化合物ｂとのうち沸点が高い一方の沸点を溶媒１７の沸点とみなす。溶媒１７は有機化合物であること、すなわち有機溶媒であることが好ましい。 When the solvent 17 is a mixture of a plurality of compounds, the boiling point of the compound having the largest mass ratio is regarded as the boiling point of the solvent 17. When the solvent 17 is a mixture of three or more kinds of compounds and there are a plurality of compounds having the highest mass ratio, the boiling point of the compound having the highest boiling point is regarded as the boiling point of the solvent 17. For example, the solvent 17 is a mixture of compound a, compound b, and compound c, and the mass is (mass of compound a) :( mass of compound b) :( mass of compound c) = 40:40:20. When the compound having the highest ratio is compound a and compound b, the boiling point of one of compound a and compound b having the higher boiling point is regarded as the boiling point of the solvent 17. The solvent 17 is preferably an organic compound, that is, an organic solvent.
　電解質１８は、塩化リチウム（ＬｉＣｌ）、臭化リチウム（ＬｉＢｒ）、塩化カルシウム（ＣａＣｌ２　）などである。電解質１８を添加することで、溶液２３ａの電気伝導度が２ｍＳ／ｍより大きく５０ｍＳ／ｍ未満の範囲に調整される。なお、溶液２３ａの電気伝導度は、５ｍＳ／ｍより大きく４０ｍＳ／ｍ未満の範囲であることがより好ましく、１０ｍＳ／ｍより大きく３０ｍＳ／ｍ未満の範囲であることがさらに好ましい。 The electrolyte 18 is lithium chloride (LiCl), lithium bromide (LiBr), calcium chloride (CaCl 2 ) and the like. By adding the electrolyte 18, the electrical conductivity of the solution 23a is adjusted to a range of more than 2 mS / m and less than 50 mS / m. The electrical conductivity of the solution 23a is more preferably in the range of more than 5 mS / m and less than 40 mS / m, and further preferably in the range of more than 10 mS / m and less than 30 mS / m.
　このように、電解質１８を添加することにより、目付を大きくできる。つまり、溶液２３ａが電気伝導性を有することにより、電気先導性を有さない場合と比較して、後述するコレクタ５２の近傍におけるファイバ１１の帯電量を小さく抑え、ファイバ１１同士の反発を抑制できる。これにより、目付を大きくできる。また、電解質１８を添加することにより、ファイバ１１の細径化も可能である。つまり、溶液２３ａが電気伝導性を有することにより、紡糸開始時などに後述するノズル２５ａの先端部の溶液２３ａに電荷が集まり易く、溶液２３ａが電気伝導性を有さない場合と比較して、より強い力で溶液２３ａがコレクタ５２側に誘引される。これにより、ファイバ１１の細径化が可能となる。 In this way, by adding the electrolyte 18, the basis weight can be increased. That is, since the solution 23a has electrical conductivity, the amount of charge of the fibers 11 in the vicinity of the collector 52, which will be described later, can be suppressed to be small and the repulsion between the fibers can be suppressed as compared with the case where the solution 23a does not have electrical leadability. .. As a result, the basis weight can be increased. Further, the diameter of the fiber 11 can be reduced by adding the electrolyte 18. That is, since the solution 23a has electrical conductivity, electric charges tend to collect in the solution 23a at the tip of the nozzle 25a, which will be described later, at the start of spinning or the like, and the solution 23a does not have electrical conductivity, as compared with the case where the solution 23a does not have electrical conductivity. The solution 23a is attracted to the collector 52 side with a stronger force. This makes it possible to reduce the diameter of the fiber 11.
　なお、本実施形態では、ファイバ材１６と溶媒１７と電解質１８とを同時に混合することにより溶液２３ａを生成しているが、本発明はこれに限定されない。ファイバ材１６を溶媒１７により溶解したもの（溶液）に、電解質１８を添加することにより溶液２３ａを生成してもよい。また、溶媒１７に電解質１８を添加したもの（溶媒）で、ファイバ材１６を溶解させることにより溶液２３ａを生成してもよい。ただし、ファイバ材１６は、溶液にすると粘性が高くなり、電解質１８を溶解させるために時間がかかってしまう。このため、溶媒１７に電解質１８を添加したもの（溶媒）で、ファイバ材１６を溶解させることにより溶液２３ａを生成することが好ましい。 In the present embodiment, the solution 23a is produced by simultaneously mixing the fiber material 16, the solvent 17, and the electrolyte 18, but the present invention is not limited to this. The solution 23a may be produced by adding the electrolyte 18 to the fiber material 16 dissolved in the solvent 17 (solution). Further, the solution 23a may be produced by dissolving the fiber material 16 with a solvent 17 to which the electrolyte 18 is added (solvent). However, the fiber material 16 becomes highly viscous when made into a solution, and it takes time to dissolve the electrolyte 18. Therefore, it is preferable to generate the solution 23a by dissolving the fiber material 16 with a solvent 17 to which the electrolyte 18 is added (solvent).
　不織布製造部２４は、ノズルユニット２５と、集積部２６と、電源２７と、噴霧器２８とを備える。ノズルユニット２５は、後述する支持体３０の幅方向に長く形成されている（図２参照）。また、本実施形態では、前述のように支持体３０の幅方向に長いノズルユニット２５を、支持体３０の長手方向に並べて配置しており、本実施形態では、３つのノズルユニット２５を配置している（ノズルユニット２５を３列設けている）（図３参照）。これらノズルユニット２５には、ノズルユニット２５の長手方向（すなわち、支持体３０の幅方向）に沿って複数（本実施形態では３つ）のノズル２５ａが並べて配されている（図２参照）。各ノズル２５ａには、溶液調製部２３によって調製された溶液２３ａが供給され、溶液２３ａは、各ノズル２５ａから集積部２６へ向けて吐出される。なお、ノズルユニット２５の数、及び、各ノズルユニット２５に設けるノズル２５ａの数については、本実施形態に限定されず、適宜変更できる。 The non-woven fabric manufacturing unit 24 includes a nozzle unit 25, an integrated unit 26, a power supply 27, and a sprayer 28. The nozzle unit 25 is formed long in the width direction of the support 30 described later (see FIG. 2). Further, in the present embodiment, as described above, the nozzle units 25 long in the width direction of the support 30 are arranged side by side in the longitudinal direction of the support 30, and in the present embodiment, the three nozzle units 25 are arranged. (Three rows of nozzle units 25 are provided) (see FIG. 3). In these nozzle units 25, a plurality of nozzles 25a (three in the present embodiment) are arranged side by side along the longitudinal direction of the nozzle unit 25 (that is, the width direction of the support 30) (see FIG. 2). The solution 23a prepared by the solution preparation unit 23 is supplied to each nozzle 25a, and the solution 23a is discharged from each nozzle 25a toward the integration unit 26. The number of nozzle units 25 and the number of nozzles 25a provided in each nozzle unit 25 are not limited to this embodiment and can be changed as appropriate.
　集積部２６は、コレクタ５２と、支持体供給部５７と、支持体巻取部５８とを有する。コレクタ５２はノズル２５ａから吐出された溶液２３ａを誘引し、形成されたファイバ１１を捕集して不織布１０を得るためのものであり、本実施形態では、ファイバ１１を後述の支持体３０上に捕集する。コレクタ５２は、金属製の帯状物で環状に形成された無端ベルトで構成され、ローラ６１、６２に張り渡され、ローラ６１、６２の回転に伴って循環移動する。 The collecting unit 26 has a collector 52, a support supply unit 57, and a support winding unit 58. The collector 52 is for attracting the solution 23a discharged from the nozzle 25a and collecting the formed fibers 11 to obtain the non-woven fabric 10. In the present embodiment, the fibers 11 are placed on the support 30 described later. Collect. The collector 52 is composed of an endless belt formed of a metal strip in an annular shape, is stretched over the rollers 61 and 62, and circulates and moves with the rotation of the rollers 61 and 62.
　なお、図２では、図面の煩雑化を避けるため、支持体供給部５７、支持体巻取部５８、ローラ６１、６２、及び、後述する噴霧器２８、並びに液体供給部３１については図示を省略している。また、本実施形態では、支持体３０上にファイバ１１を捕集する例で説明をしたが、支持体３０を介さずに（廃止して）コレクタ５２上に直接、ファイバ１１を捕集する構成としてもよい。さらに、本実施形態では、２つのローラ間に張り渡された無端ベルト上にファイバ１１を捕集する例、すなわち、コレクタが無端ベルトである例で説明をしたが、本発明はこれに限定されない。例えば、回転ドラムの周面上にファイバ１１を捕集する構成としてもよい、すなわち、コレクタが回転ドラムであってもよい。 In FIG. 2, in order to avoid complication of the drawings, the support supply unit 57, the support winding unit 58, the rollers 61 and 62, the atomizer 28 described later, and the liquid supply unit 31 are not shown. ing. Further, in the present embodiment, the example of collecting the fiber 11 on the support 30 has been described, but the fiber 11 is collected directly on the collector 52 without going through the support 30 (abolished). May be. Further, in the present embodiment, an example in which the fiber 11 is collected on an endless belt stretched between two rollers, that is, an example in which the collector is an endless belt has been described, but the present invention is not limited thereto. .. For example, the fiber 11 may be collected on the peripheral surface of the rotating drum, that is, the collector may be the rotating drum.
　コレクタ５２とノズルユニット２５（ノズル２５ａ）との間には電源２７により電圧が印加される。これにより、コレクタ５２とノズル２５ａとのうち一方がプラス（＋）に帯電し、他方がマイナス（－）に帯電する。こうすることで、溶液２３ａがコレクタ５２側へ誘引され、ノズル２５ａからコレクタ５２へ向けて噴出される。コレクタ５２は、電源２７によって電圧が印加されることにより帯電する素材から形成されていればよく、例えば、ステンレス製とされる。なお、本実施形態では、ノズル２５ａを（＋）、コレクタ５２を（－）に帯電させているが、ノズル２５ａとコレクタ５２との極性は逆であってもよい。また、コレクタ５２とノズル２５ａとの一方をアースして電位を０とする構成としてもよい。 A voltage is applied between the collector 52 and the nozzle unit 25 (nozzle 25a) by the power supply 27. As a result, one of the collector 52 and the nozzle 25a is positively (+) charged, and the other is negatively (−) charged. By doing so, the solution 23a is attracted to the collector 52 side and ejected from the nozzle 25a toward the collector 52. The collector 52 may be made of a material that is charged by applying a voltage from the power supply 27, and is made of, for example, stainless steel. In the present embodiment, the nozzle 25a is charged with (+) and the collector 52 is charged with (−), but the polarities of the nozzle 25a and the collector 52 may be opposite. Further, one of the collector 52 and the nozzle 25a may be grounded to set the potential to 0.
　支持体供給部５７は、例えば、帯状のアルミニウムシートからなる支持体３０をコレクタ５２に供給する。支持体３０は、コレクタ５２の移動に伴って移動し、ノズルユニット２５の下方を通過する。この間に、ノズル２５ａから噴出したファイバ１１が支持体３０上に順次捕集されて帯状の不織布１０が形成される。この後、不織布１０から支持体３０が剥がされ、支持体３０は、支持体巻取部５８に巻き取られる。このようにして形成された不織布１０は、ファイバ１１同士が絡み合う絡み合い構造が、第１表面１０Ａから第２表面１０Ｂまで途切れることなく連続していることにより厚みを有するとともに、複数の空隙１４を有するものである（図１参照）。 The support supply unit 57 supplies, for example, a support 30 made of a strip-shaped aluminum sheet to the collector 52. The support 30 moves with the movement of the collector 52 and passes below the nozzle unit 25. During this time, the fibers 11 ejected from the nozzle 25a are sequentially collected on the support 30 to form the strip-shaped non-woven fabric 10. After that, the support 30 is peeled off from the non-woven fabric 10, and the support 30 is wound around the support winding portion 58. The non-woven fabric 10 formed in this way has a thickness due to the entangled structure in which the fibers 11 are entangled with each other continuously from the first surface 10A to the second surface 10B without interruption, and also has a plurality of voids 14. (See Fig. 1).
　なお、加熱工程を設け、支持体３０とともに不織布１０を加熱、または、支持体３０を剥がした後に不織布１０を単体で加熱してもよい。不織布１０を加熱することで、不織布１０から残留応力（捕集の際にファイバ１１に蓄積された力であり、ファイバ１１を湾曲させている力）が除去され、ファイバ１１が直線化される。また、延伸工程を設け、支持体３０とともに不織布１０を延伸、または、支持体３０を剥がした後に不織布１０を単体で延伸してもよい。もちろん、延伸を、前述した加熱と同期して行ってもよい。延伸を行うことで、ファイバ１１を直線化できる。また、空隙１４の孔径を調整（拡大）できる。 A heating step may be provided to heat the non-woven fabric 10 together with the support 30, or the non-woven fabric 10 may be heated by itself after the support 30 is peeled off. By heating the non-woven fabric 10, residual stress (force accumulated in the fiber 11 at the time of collection and bending the fiber 11) is removed from the non-woven fabric 10, and the fiber 11 is straightened. Further, a stretching step may be provided to stretch the non-woven fabric 10 together with the support 30, or the non-woven fabric 10 may be stretched by itself after the support 30 is peeled off. Of course, the stretching may be performed in synchronization with the heating described above. By stretching, the fiber 11 can be straightened. Further, the pore diameter of the void 14 can be adjusted (enlarged).
　噴霧器２８には、液体供給部３１から、導電性を有する導電性液体３１ａが供給される。噴霧器２８は、液体供給部３１から供給された導電性液体３１ａを、コレクタ５２に捕集されたファイバ１１へ向けて噴霧して付着させる。このように、導電性液体３１ａを付着させることにより、コレクタ５２の近傍において導電性が向上してファイバ１１が除電される（ファイバ１１の帯電量を減少できる）。これにより、ファイバ１１同士の反発を抑制し、目付を大きくできる。 A conductive liquid 31a having conductivity is supplied to the sprayer 28 from the liquid supply unit 31. The sprayer 28 sprays and adheres the conductive liquid 31a supplied from the liquid supply unit 31 toward the fiber 11 collected by the collector 52. By adhering the conductive liquid 31a in this way, the conductivity is improved in the vicinity of the collector 52 and the fiber 11 is statically eliminated (the charge amount of the fiber 11 can be reduced). As a result, the repulsion between the fibers 11 can be suppressed and the basis weight can be increased.
　導電性液体３１ａは、例えば、純水に電解質を添加することで生成できる。電解質としては、例えば、塩化ナトリウム、塩化カリウム、塩化カルシウム、塩化リチウム、塩化マグネシウムなどを用いることができる。そして、本実施形態では、電解質として塩化ナトリウムを用い、０．００１ｗｔ％（重量濃度）の水溶液に調整することにより生成した導電率（電気伝導度）１．９ｍＳ／ｍの導電性液体３１ａを用いている。そして、本実施形態では、このような導電性液体３１ａを、ファイバ１１が紡糸される紡糸面全体に均一に噴霧している。 The conductive liquid 31a can be produced, for example, by adding an electrolyte to pure water. As the electrolyte, for example, sodium chloride, potassium chloride, calcium chloride, lithium chloride, magnesium chloride and the like can be used. Then, in this embodiment, sodium chloride is used as the electrolyte, and a conductive liquid 31a having a conductivity (electrical conductivity) of 1.9 mS / m produced by adjusting to an aqueous solution of 0.001 wt% (weight concentration) is used. ing. Then, in the present embodiment, such a conductive liquid 31a is uniformly sprayed on the entire spinning surface on which the fiber 11 is spun.
　また、本実施形態では、この導電性液体３１ａを、ファイバ１１の目付と同等の目付で噴霧している。つまり、特定の範囲内にファイバ１１が１ｇ紡糸（捕集）された場合、この特定の範囲内に１ｇの導電性液体３１ａを噴霧している。このように導電性液体３１ａを噴霧することにより、ファイバ１１の目付と同等の導電性液体３１ａがファイバ１１に付着している状態で紡糸することが好ましい。しかし、噴霧した導電性液体３１ａの全てがファイバ１１に付着するわけではなく、導電性液体３１ａの一部はファイバ１１とは別の場所に飛散する。また、ファイバ１１に付着した導電性液体３１ａについても、時間の経過に伴う蒸発などにより減少する。このため、導電性液体３１ａの噴霧量は、ファイバ１１の目付と同等～２倍程度の範囲であること、すなわち、ファイバ１１の目付よりも多くの導電性液体３１ａを噴霧することが好ましい。こうすることで、ファイバ１１の目付と同等の導電性液体３１ａがファイバ１１に付着した状態で紡糸を行うことができる。 Further, in the present embodiment, the conductive liquid 31a is sprayed with a basis weight equivalent to that of the fiber 11. That is, when 1 g of the fiber 11 is spun (collected) within a specific range, 1 g of the conductive liquid 31a is sprayed within this specific range. By spraying the conductive liquid 31a in this way, it is preferable to spin the fiber 11 in a state where the conductive liquid 31a equivalent to the basis weight of the fiber 11 is attached to the fiber 11. However, not all of the sprayed conductive liquid 31a adheres to the fiber 11, and a part of the conductive liquid 31a is scattered in a place different from the fiber 11. Further, the conductive liquid 31a adhering to the fiber 11 also decreases due to evaporation or the like with the passage of time. Therefore, it is preferable that the amount of the conductive liquid 31a sprayed is in the range of about the same as or about twice the basis weight of the fiber 11, that is, more conductive liquid 31a is sprayed than the basis weight of the fiber 11. By doing so, spinning can be performed in a state where the conductive liquid 31a having the same basis weight as the fiber 11 is attached to the fiber 11.
　導電性液体３１ａの電気伝導度は、上記に限定されるものではないが、電気伝導度が低いと、ファイバ１１同士の反発を抑制して目付を大きくするために、より多くの導電性液体３１ａを噴霧する必要がある。この場合、導電性液体３１ａの重さや張力によりファイバ１１同士の間隔が狭くなり空隙率が低下してしまう。他方、電気伝導度が高いと、導電性液体３１ａの噴霧量を減らすことができ、空隙率の低下を防止できる反面、導電性液体３１ａを均質に付着させることが難しく、導電性液体３１ａの付着が少ない部分ではファイバ１１同士の反発を抑制できず、導電性液体３１ａの付着が多い部分では空隙率が低下したり導電性液体３１ａの成分が不織布１０に残留してしまうといった問題がある。このため、導電性液体３１ａの電気伝導度は、０．１ｍＳ／ｍ以上５０ｍＳ／ｍ以下の範囲内であることが好ましく、０．２ｍＳ／ｍ以上３０ｍＳ／ｍ以下の範囲内であることがより好ましく、１ｍＳ／ｍ以上２０ｍＳ／ｍ以下の範囲内であることがさらに好ましい。 The electrical conductivity of the conductive liquid 31a is not limited to the above, but when the electrical conductivity is low, more conductive liquid 31a is used in order to suppress repulsion between the fibers 11 and increase the basis weight. Need to be sprayed. In this case, the distance between the fibers 11 becomes narrow due to the weight and tension of the conductive liquid 31a, and the porosity decreases. On the other hand, when the electrical conductivity is high, the spray amount of the conductive liquid 31a can be reduced and the decrease in the void ratio can be prevented, but on the other hand, it is difficult to uniformly adhere the conductive liquid 31a, and the conductive liquid 31a adheres. There is a problem that the repulsion between the fibers 11 cannot be suppressed in the portion where there is little, and the void ratio is lowered or the component of the conductive liquid 31a remains in the non-woven fabric 10 in the portion where the conductive liquid 31a adheres a lot. Therefore, the electrical conductivity of the conductive liquid 31a is preferably in the range of 0.1 mS / m or more and 50 mS / m or less, and more preferably in the range of 0.2 mS / m or more and 30 mS / m or less. It is preferably in the range of 1 mS / m or more and 20 mS / m or less.
　導電性液体３１ａの生成においては、純水を用いることが好ましく、より好ましくは超純水を用いることである。不純物が少ない方が電気伝導度の調整が容易となるからである。ただし、導電性液体３１ａは、ファイバ１１を溶解させないものであることが好ましいため、ファイバ１１が水に溶解する性質を有する場合については、ファイバ１１を溶解させない溶媒を用いて導電性液体３１ａを生成することが好ましい。 In the production of the conductive liquid 31a, it is preferable to use pure water, and more preferably ultrapure water is used. This is because the smaller the number of impurities, the easier it is to adjust the electrical conductivity. However, since the conductive liquid 31a preferably does not dissolve the fiber 11, when the fiber 11 has a property of being soluble in water, the conductive liquid 31a is generated by using a solvent that does not dissolve the fiber 11. It is preferable to do so.
　なお、本実施形態では、導電性液体３１ａを噴霧してファイバ１１に付着させているが、導電性液体３１ａは、スプレー、シャワー、塗布、浸漬など、周知の各種の手法でファイバ１１に付着させることができる。 In the present embodiment, the conductive liquid 31a is sprayed and adhered to the fiber 11, but the conductive liquid 31a is adhered to the fiber 11 by various well-known methods such as spraying, showering, coating, and dipping. be able to.
　以下、本発明の効果を検証した検証結果について説明する。検証は、図２、図３に示す不織布製造設備１５を用いて製造した実施例１～８の不織布１０を、本発明の不織布製造設備を用いずに製造した比較例１～４の不織布と比較することにより行った。実施例１～８、及び、比較例１～４の製造方法（ファイバ材１６、溶媒１７、電解質１８の種類及び有無、溶液２３ａの電気伝導度、導電性液体３１ａの噴霧（付着）の有無）、及び、製造された不織布（繊維径、空隙率、目付、厚み）は、表１に示す通りである。 Hereinafter, the verification results for verifying the effects of the present invention will be described. In the verification, the non-woven fabrics 10 of Examples 1 to 8 manufactured using the non-woven fabric manufacturing equipment 15 shown in FIGS. 2 and 3 are compared with the non-woven fabrics of Comparative Examples 1 to 4 manufactured without using the non-woven fabric manufacturing equipment of the present invention. I went by doing. Production methods of Examples 1 to 8 and Comparative Examples 1 to 4 (type and presence / absence of fiber material 16, solvent 17, electrolyte 18, electrical conductivity of solution 23a, presence / absence of spraying (adhesion) of conductive liquid 31a) , And the produced non-woven fabric (fiber diameter, void ratio, texture, thickness) are as shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
  
Figure JPOXMLDOC01-appb-T000001
  
　表１に示すように、本発明を実施した実施例１～８については、平均線径も細く（平均線径１０ｎｍ以上２０００ｎｍ以下であり）、空隙率も大きく（空隙率９０％以上であり）、目付も大きい（目付１２０ｇ／ｍ２　以上であり）、良好な性能の不織布１０が得られた。 As shown in Table 1, in Examples 1 to 8 in which the present invention was carried out, the average wire diameter was small (the average wire diameter was 10 nm or more and 2000 nm or less), and the porosity was large (the porosity was 90% or more). A non-woven fabric 10 having a large basis weight (with a basis weight of 120 g / m 2 or more) and good performance was obtained.
　一方、導電性液体３１ａを付着させずに製造を行った比較例１では、目付が小さかった。また、溶液２３ａに電解質１８を添加せずに溶液２３ａの電気伝導度が小さい状態（電気伝導度２ｍＳ／ｍ以下で）製造を行った比較例２では、平均線径が太く、また、空隙率も低かった。さらに、溶液２３ａの電気伝導度が大きい状態（電気伝導度５０ｍＳ／ｍ以上で）製造を行った比較例３では、ノズル２５ａとコレクタ５２とが通電状態であるとみなされて製造設備の安全装置が作動し、紡糸を行うことができなかった。また、溶液２３ａに電解質１８を添加せずに溶液２３ａの電気伝導度が小さい状態であり、かつ、導電性液体３１ａを付着させずに製造を行った比較例４では、平均線径が太く、また、空隙率も低く、さらには、目付も小さかった。 On the other hand, in Comparative Example 1 produced without adhering the conductive liquid 31a, the basis weight was small. Further, in Comparative Example 2 in which the solution 23a was manufactured in a state where the electric conductivity of the solution 23a was small (with an electric conductivity of 2 mS / m or less) without adding the electrolyte 18, the average wire diameter was large and the porosity was large. Was also low. Further, in Comparative Example 3 in which the solution 23a was manufactured in a state where the electric conductivity is large (electrical conductivity is 50 mS / m or more), the nozzle 25a and the collector 52 are considered to be in the energized state, and the safety device of the manufacturing equipment is used. Was activated and spinning could not be performed. Further, in Comparative Example 4 in which the electric conductivity of the solution 23a was small without adding the electrolyte 18 to the solution 23a and the solution 23a was manufactured without adhering the conductive liquid 31a, the average wire diameter was large. In addition, the porosity was low, and the texture was also small.
　以上から、本発明を実施することにより、良好な性能の不織布１０を得られることが確認できた。 From the above, it was confirmed that the non-woven fabric 10 having good performance can be obtained by carrying out the present invention.
　１０　　不織布
　１０Ａ　第１表面
　１０Ｂ　第２表面
　１１　ファイバ
　１４　空隙
　１５　不織布製造設備
　１６　ファイバ材
　１７　溶媒
　１８　電解質
　２３　溶液調整部
　２３ａ　溶液
　２４　不織布製造部
　２５　ノズルユニット
　２５ａ　ノズル
　２６　集積部
　２７　電源
　２８　噴霧器
　３０　支持体
　３１　液体供給部
　３１ａ　導電性液体
　５２　コレクタ
　５７　支持体供給部
　５８　支持体巻取部
　６１、６２　ローラ 10 Non-woven fabric 10A 1st surface 10B 2nd surface 11 Fiber 14 Void 15 Non-woven fabric manufacturing equipment 16 Fiber material 17 Solvent 18 Electrolyte 23 Solution adjustment part 23a Solution 24 Non-woven fabric manufacturing part 25 Nozzle unit 25a Nozzle 26 Integrated part 27 Power supply 28 Atomizer 30 Support 31 Liquid supply part 31a Conductive liquid 52 Collector 57 Support supply part 58 Support winding part 61, 62 Roller

Claims (16)

  1. 　平均線径が１０ｎｍ以上２０００ｎｍ以下の範囲内であるファイバを備え、
    　空隙率が少なくとも９０％であり、
    　目付が１２０ｇ／ｍ２　以上２０００ｇ／ｍ２　以下の範囲内である不織布。     A fiber having an average wire diameter in the range of 10 nm or more and 2000 nm or less is provided.
    Porosity is at least 90%
    A non-woven fabric having a basis weight in the range of 120 g / m 2 or more and 2000 g / m 2 or less.
  2. 　前記ファイバは、セルロース系ポリマーで形成される請求項１に記載の不織布。 The non-woven fabric according to claim 1, wherein the fiber is made of a cellulosic polymer.
  3. 　前記セルロース系ポリマーは、セルロースアシレートである請求項１または２に記載の不織布。 The non-woven fabric according to claim 1 or 2, wherein the cellulosic polymer is a cellulose acylate.
  4. 　前記ファイバが絡み合う絡み合い構造を有し、前記絡み合い構造が、当該不織布の一方の表面側から他方の表面側まで連続している請求項１～３のいずれか１項に記載の不織布。 The non-woven fabric according to any one of claims 1 to 3, which has an entangled structure in which the fibers are entangled, and the entangled structure is continuous from one surface side of the non-woven fabric to the other surface side.
  5. 　溶媒にファイバ材が溶解している溶液とコレクタとの間に電圧を印加し、前記溶液をノズルから噴出することにより形成したファイバを、前記コレクタの表面に捕集する不織布製造方法において、
    　前記溶液の電気伝導度が２ｍＳ／ｍより大きく、５０ｍＳ／ｍ未満の範囲内であり、
    　前記コレクタの表面に捕集された前記ファイバに対して導電性を有する導電性液体を付着させる不織布製造方法。     In a non-woven fabric manufacturing method in which a voltage is applied between a solution in which a fiber material is dissolved in a solvent and a collector, and the fiber formed by ejecting the solution from a nozzle is collected on the surface of the collector.
    The electrical conductivity of the solution is greater than 2 mS / m and less than 50 mS / m.
    A method for producing a non-woven fabric, in which a conductive liquid having conductivity is attached to the fiber collected on the surface of the collector.
  6. 　電解質を添加して、前記溶液の電気伝導度を調整する請求項５に記載の不織布製造方法。 The non-woven fabric manufacturing method according to claim 5, wherein an electrolyte is added to adjust the electrical conductivity of the solution.
  7. 　前記電解質は、塩化リチウム、臭化リチウム、塩化カルシウムのいずれかである請求項６に記載の不織布製造方法。 The method for producing a non-woven fabric according to claim 6, wherein the electrolyte is lithium chloride, lithium bromide, or calcium chloride.
  8. 　前記溶媒は、複数の化合物の混合物である請求項５～７のいずれか１項に記載の不織布製造方法。 The method for producing a non-woven fabric according to any one of claims 5 to 7, wherein the solvent is a mixture of a plurality of compounds.
  9. 　前記溶媒は、沸点８０℃以下である請求項５～８のいずれか１項に記載の不織布製造方法。 The method for producing a non-woven fabric according to any one of claims 5 to 8, wherein the solvent has a boiling point of 80 ° C. or lower.
  10. 　前記溶媒は、ジクロロメタンとメタノールとを含有する請求項５～９のいずれか１項に記載の不織布製造方法。 The method for producing a non-woven fabric according to any one of claims 5 to 9, wherein the solvent contains dichloromethane and methanol.
  11. 　前記ファイバ材は、セルロース系ポリマーである請求項５～１０のいずれか１項に記載の不織布製造方法。 The method for producing a non-woven fabric according to any one of claims 5 to 10, wherein the fiber material is a cellulosic polymer.
  12. 　前記セルロース系ポリマーは、セルロースアシレートである請求項１１に記載の不織布製造方法。 The method for producing a non-woven fabric according to claim 11, wherein the cellulosic polymer is a cellulose acylate.
  13. 　前記セルロースアシレートは、セルロースアセテートプロピオネート、セルローストリアセテートのいずれかである請求項１２に記載の不織布製造方法。 The method for producing a non-woven fabric according to claim 12, wherein the cellulose acylate is either cellulose acetate propionate or cellulose triacetate.
  14. 　前記導電性液体の電気伝導度が０．１ｍＳ／ｍ以上、５０ｍＳ／ｍ以下の範囲内である請求項５～１３のいずれか１項に記載の不織布製造方法。 The non-woven fabric manufacturing method according to any one of claims 5 to 13, wherein the electric conductivity of the conductive liquid is within the range of 0.1 mS / m or more and 50 mS / m or less.
  15. 　前記導電性液体を噴霧して付着させる請求項５～１４のいずれか１項に記載の不織布製造方法。 The non-woven fabric manufacturing method according to any one of claims 5 to 14, wherein the conductive liquid is sprayed and adhered.
  16. 　前記不織布は、前記ファイバが絡み合う絡み合い構造を有し、前記絡み合い構造が、前記不織布の一方の表面側から他方の表面側まで連続している請求項５～１５のいずれか１項に記載の不織布製造方法。 The non-woven fabric according to any one of claims 5 to 15, wherein the non-woven fabric has an entangled structure in which the fibers are entangled, and the entangled structure is continuous from one surface side of the non-woven fabric to the other surface side. Production method.
PCT/JP2021/005336 2020-03-30 2021-02-12 Nonwoven fabric and method for manufacturing nonwoven fabric WO2021199717A1 (en)

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