JP7074433B2 - Fiber sheet manufacturing equipment and fiber sheet manufacturing method - Google Patents

Description

The present invention relates to a fiber sheet manufacturing apparatus and a fiber sheet manufacturing method.

The electrospinning method (electrospinning method) is attracting attention as a technique capable of producing a fiber sheet having fibers having a nano-sized diameter (hereinafter, also referred to as fibers) easily and with high productivity. In the electrospinning method, a high voltage is applied to a solution or melt of a resin that is a raw material of a fiber to form a fiber. In the electrospinning method using a resin solution, the resin solution is placed in a syringe, and the resin solution is placed between the nozzle attached to the tip of the syringe and the collection electrode installed facing each other at a predetermined distance from the nozzle. Apply high voltage. The resin solution discharged from the tip of the nozzle is stretched by Coulomb force and the solvent evaporates instantly. The resin from which the solvent has evaporated is elongated while coagulating to form fibers, which are attracted to the collection electrode. The formed fibers are deposited on the surface of the collection electrode to form a sheet.

Patent Document 1 proposes a method for manufacturing a fiber structure by an electrospinning method and an apparatus thereof. The apparatus used in the method of Patent Document 1 is provided with a thickness measuring unit for measuring the thickness of the manufactured fiber structure, and discharges the thickness of the fiber structure measured by the thickness measuring unit and the resin solution. In conjunction with a pressure control device that controls the gas pressure for the fiber structure, the thickness of the fiber structure in the transport direction (flow direction) is controlled.

Patent Document 2 proposes a non-woven fabric manufacturing apparatus in which a plurality of electrodes used for electrospinning are arranged. A plurality of electrodes and a voltage changing means capable of periodically changing the voltage application to each electrode are connected to this manufacturing apparatus, and a variable electric field is generated in the electrodes by the voltage changing means. It controls the thickness of the non-woven fabric.

JP-A-2007-092237 Japanese Unexamined Patent Publication No. 2008-144327

Although the apparatus of Patent Document 1 can control the thickness of the fiber sheet in the transport direction, the thickness in the width direction is not controlled, and it is easy to manufacture a fiber sheet having a uniform basis weight in the width direction. Not. In addition, droplet defects are likely to occur due to the appropriate change in the discharge amount of the resin solution, and as a result, it is not easy to improve the quality of the fiber sheet and the product using the fiber sheet.

In the apparatus of Patent Document 2, the fluctuating voltage applied to the electrodes and the change in the basis weight of the actually manufactured fiber sheet are not linked. As a result, fiber sheets having uneven basis weight distribution are periodically produced, and it is not easy to constantly produce high-quality fiber sheets.

Therefore, an object of the present invention is to provide a fiber sheet manufacturing apparatus and a manufacturing method capable of making the basis weight distribution in the width direction of a fiber sheet made of fibers constant.

The present invention comprises a transport belt for depositing and transporting fibers spun by an electric field spinning device.
An electrode group consisting of a plurality of electrodes arranged on the back surface of the transport belt, and
A voltage application unit that applies voltage to each electrode of the electrode group, and
A fiber sheet manufacturing apparatus including a voltage control unit that individually controls the voltage applied to each electrode of the electrode group from the voltage application unit.
Each electrode of the electrode group provides a fiber sheet manufacturing apparatus arranged along a direction intersecting the transport direction of the transport belt.

Further, in the present invention, each electrode of the electrode group consisting of a plurality of electrodes is arranged on the back surface of the traveling transport belt along the direction intersecting the transport direction of the transport belt, and on the front surface of the transport belt. It is a method of manufacturing a fiber sheet for depositing fibers spun by an electric field spinning device.
The basis weight distribution along the width direction of the fiber conveyed by the transfer belt is measured, and in the portion where the basis weight is lower than the target basis weight value, the deposition of the fiber in the portion is increased in the portion. The voltage applied to the electrode arranged at the corresponding position is adjusted, and the position corresponding to the portion is such that the deposition of fibers on the portion is reduced in the portion having a basis weight higher than the target average value. It provides a method of manufacturing a fiber sheet which adjusts the applied voltage of the electrode arranged in the above.

According to the present invention, it is possible to easily manufacture a fiber sheet having a constant basis weight distribution in the width direction.

FIG. 1 is a schematic view of the manufacturing apparatus of the present invention as viewed from the side. 2 (a) is an enlarged view of a main part of the collecting part in FIG. 1, and FIG. 2 (b) is a schematic view of the collecting part of FIG. 2 (a) as viewed from the front. c) is a schematic view of the schematic view of FIG. 2 (b) seen from the lower surface. 3A to 3F are schematic views showing another embodiment of the electrode of the collecting portion in the manufacturing apparatus of the present invention. FIG. 4 is an enlarged view of a main part showing an embodiment of a basis weight distribution measuring unit in the manufacturing apparatus of the present invention. FIG. 5 is an enlarged view of a main part showing another embodiment of the basis weight distribution measuring part in the manufacturing apparatus of the present invention. FIG. 6 is a graph of the basis weight distribution over the width direction of the fiber sheet in Comparative Example 1. FIG. 7 is a graph of the basis weight distribution over the width direction of the fiber sheet in Example 1. FIG. 8 is a graph of the basis weight distribution over the width direction of the fiber sheet in Example 2.

Hereinafter, the present invention will be described based on the preferred embodiment thereof with reference to the drawings. FIG. 1 schematically shows an embodiment of the fiber sheet manufacturing apparatus of the present invention. The manufacturing apparatus 10 shown in FIG. 1 is roughly classified into an electric field spinning unit 20, a collecting unit 30, and an evaluation unit 40.

The electric field spinning unit 20 is a device for spinning by discharging a solution or a melt of a raw material resin supplied from a raw material supply unit (not shown). The electric field spinning unit 20 is arranged so as to face the collecting unit 30. In the following description, the solution or melt of the raw material resin is also collectively referred to as “raw material liquid”.

The electric field spinning unit 20 includes a nozzle 21 for discharging the raw material liquid L and a charging electrode 22 for charging the raw material liquid L. The nozzle 21 is made of a conductive material such as metal and has a hollow needle-like structure. The charged electrode 22 has a substantially bowl shape as a whole, and the surface facing the nozzle 21 side is a concave surface. The nozzle 21 is provided at the bottom of the charging electrode 22, and has a shape surrounded by the charging electrode 22. It is preferable to provide an insulator (not shown) between the nozzle 21 and the charged electrode 22 to electrically insulate them. The tip 21a of the nozzle 21 is exposed inside the charging electrode 22. The rear end 21b of the nozzle 21 is connected to the raw material supply unit on the back surface side of the charging electrode 22. A high voltage power supply 23 is connected to the charging electrode 22. As the high voltage power supply 23, a known device such as a DC high voltage power supply can be used.

The lower limit of the inner diameter of the nozzle 21 can be set to preferably 100 μm or more, more preferably 300 μm or more. On the other hand, the upper limit value can be preferably set to 3000 μm or less, more preferably 2000 μm or less. The inner diameter of the nozzle 21 can be preferably set to 100 μm or more and 3000 μm or less, and more preferably 300 μm or more and 2000 μm or less. By setting the inner diameter of the nozzle within this range, the raw material liquid L, which is a polymer, can be easily and quantitatively sent, and the raw material liquid L can be efficiently charged, which is preferable.

In the embodiment shown in FIG. 1, the nozzle 21 is grounded and a high voltage is applied to the charging electrode 22. However, the applied voltage is not limited to this, and a positive voltage or a negative voltage may be applied to the nozzle 21, and the charging electrode 22 may be grounded. That is, it suffices if there is a potential difference between the nozzle 21 and the charged electrode 22. The potential difference applied between the nozzle 21 and the charging electrode 22 is preferably 1 kV or more, particularly preferably 10 kV or more, from the viewpoint of sufficiently charging the raw material liquid L. On the other hand, it is preferable that this potential difference is 100 kV or less, particularly 50 kV or less, from the viewpoint of preventing discharge between the nozzle 21 and the charged electrode 22. The potential difference is preferably, for example, 1 kV or more and 100 kV or less, particularly preferably 10 kV or more and 50 kV or less.

In order to further concentrate the charge on the tip of the nozzle 21, the nozzle 21 extends in the center of the circle defined by the open end of the charging electrode 22 or near the center thereof. Moreover, it is advantageous that the tip 21a of the nozzle 21 is located in the plane including the circle defined by the open end, or is arranged so as to be located in the vicinity of the plane.

In particular, the nozzle 21 is arranged so that its extending direction passes through the center of the circle defined by the open end of the concave curved surface 24 of the charging electrode 22 or the vicinity of the center thereof and the bottom of the charging electrode 22. It is preferable to be done. It is preferable that the plane including the circle defined by the open end of the charging electrode 22 and the extending direction of the nozzle 21 are orthogonal to each other. By arranging the nozzle 21 in this way, the electric charge is further concentrated on the tip of the nozzle 21. From this point of view, it is particularly preferable that the charged electrode 22 has a substantially hemispherical shape of a spherical shell.

Regarding the position of the tip 21a of the nozzle 21, the nozzle 21 is located in a plane including a circle defined by the open end of the charging electrode 22, or is located inside the plane. It is preferable to arrange.

As shown in FIG. 1, an air flow injection unit 25 is provided in the vicinity of the base of the nozzle 21. The air flow injection unit 25 is formed along the extending direction of the nozzle 21. The air flow injection unit 25 is located behind the tip 21a of the nozzle 21, and is formed so that the gas flow can be injected toward the tip 21a of the nozzle 21. From the viewpoint of obtaining a uniform air flow, it is desirable that the air flow injection unit 25 is provided in an annular shape so as to surround the nozzle 21. The opening on the rear end side of the air flow injection portion 25 formed of the through hole is connected to a gas flow supply source (not shown). By supplying the gas from this supply source, the gas is ejected from the periphery of the nozzle 21. The ejected gas is discharged from the tip 21a of the nozzle 21, and the raw material liquid L elongated by the action of the electric field is conveyed toward the collection electrode 31, which will be described later.

As shown in FIG. 1, the collecting unit 30 has a collecting electrode 31 for collecting the manufactured fibers S (hereinafter, also simply referred to as “electrode 31”) and a transport belt for depositing and transporting the fibers S. It is equipped with 32.

The collection electrode 31 is a flat plate made of a conductive material such as metal. The plate surface of the collection electrode 31 and the extending direction of the nozzle 21 are substantially orthogonal to each other. A voltage different from the voltage applied to the nozzle 21 is applied to the collection electrode 31 by the voltage application unit 44, which will be described later. For example, when a positive voltage is applied to the nozzle, a negative voltage can be applied to the collection electrode 31. By having this configuration, an electric field is formed between the nozzle 21 and the collection electrode 31, and electric field spinning is possible.

The transport belt 32 is composed of an endless belt, and as shown in FIG. 1, is hung between the two transport rolls 33 and 33 and is transported so as to draw an orbit in the direction R. As the transport belt 32, for example, a long strip-shaped belt may be unwound from the roll-shaped winding body instead of the endless belt. As the transport belt 32, for example, a film, a mesh, a non-woven fabric, paper, or the like can be used.

The raw material liquid L discharged from the nozzle 21 is charged by an electric field formed between the nozzle 21 and the collection electrode 31. The charged raw material liquid L is conveyed toward the collection electrode 31 while forming fine-diameter fibers by the electric repulsive force of the raw material liquid L and the air ejected from the air flow injection unit 25. The fibers having a small diameter are deposited on the transport belt 32 to form a sheet of the fiber S (hereinafter, the sheet of the fiber S is also referred to as a "fiber sheet S"). The fiber sheet S is sent out by the transport belt 32, guided by the guide roll 34, and transported to the next process.

As shown in FIG. 2A, the transport belt 32 is arranged adjacent to the collection electrode 31 and is arranged between the collection electrode 31 and the electric field spinning section 20. That is, the collection electrode 31 is arranged on the back surface of the transport belt 32. A support 35 is provided on the surface of the collection electrode 31 opposite to the surface facing the transport belt 32, and the collection electrode 31 and the support 35 are in contact with each other.

As shown in FIG. 2B, the collection electrode 31 constitutes an electrode group 31G composed of a plurality of collection electrodes 31, 31, .... The collection electrodes 31 of the electrode group 31G are arranged at intervals along the direction intersecting the transport direction R of the transport belt 32. A voltage can be applied to each of the collection electrodes 31 from the voltage application unit 44, which will be described later, to the plurality of collection electrodes 31, 31, ... That constitute the electrode group 31G.

As shown in FIGS. 2B and 2C, an electrode group is used from the viewpoint of preventing discharge from adjacent collection electrodes 31 when a high voltage is applied to the collection electrode 31. In 31G, it is preferable that the adjacent collection electrodes 31 are separated from each other by an insulator 36. As the material of the insulator 36, ceramics, plastic, or the like can be used.

The number of arrangements of the collection electrodes 31 constituting the electrode group 31G, the shape seen from the direction of the electric field spinning portion 20, and the positional relationship between the collection electrodes 31 can be measured by electric field spinning between the nozzle 21 and the electrode group 31G. There is no particular limitation as long as an electric field can be generated. For example, as shown in FIGS. 2A and 2B, a plurality of elongated rectangular collection electrodes 31 having long sides along the transport direction R of the transport belt 32 may be arranged, and FIG. 3A may be arranged. And, as shown in FIG. 3B, a plurality of elliptical or rhombic collecting electrodes 31 may be arranged. Further, as shown in FIGS. 3 (b) to 3 (d), a plurality of collection electrodes 31 may be arranged so as to be alternately positioned before and after the transport direction R. Further, as shown in FIGS. 3 (d) to 3 (f), a plurality of collection electrodes 31 having different plan-view shapes such as a triangle, a quadrangle, a rectangle, an ellipse, and a rhombus are arranged in various combinations. You may. Further, as shown in FIG. 3 (e), all the collection electrodes 31 may be rectangular, and their areas may be different from each other. Further, as shown in FIG. 3 (f), the centers of gravity of the collection electrodes 31 may not overlap.

From the viewpoint of achieving both the convenience of equipment maintenance and the uniformity of the basis weight distribution along the width direction of the manufactured fiber sheet S, the number of collection electrodes 31 arranged in the electrode group 31G is 4 or more and 15 or less. It is preferable that the shape is rectangular. From the same viewpoint, it is preferable that the electrodes 31 of the electrode group 31G are arranged at intervals along the direction orthogonal to the transport direction R of the transport belt 32.

The lower limit of the distance between the electrode group 31G and the tip of the nozzle 21 can be preferably 100 mm or more, more preferably 500 mm or more. The upper limit value can be preferably 2000 mm or less, more preferably 1500 mm or less. For example, it can be preferably 100 mm or more and 2000 mm or less, and more preferably 500 mm or more and 1500 mm or less.

The above is related to the collecting unit 30 in the manufacturing apparatus 10, and the evaluation unit 40 will be described below. As shown in FIG. 1, the evaluation unit 40 includes a take-up roll 41, a basis weight distribution measuring unit 42, a voltage control unit 43, and a voltage applying unit 44.

The take-up roll 41 recovers the fiber sheet S deposited on the transport belt 32 by taking up the fiber sheet S. The winding direction of the winding roll 41 coincides with the transport direction R.

The basis weight distribution measuring unit 42 measures the basis weight distribution along the width direction of the fiber sheet S in the process of conveying the fiber sheet S deposited on the transport belt 32 to the take-up roll 41. As shown in FIG. 1, the basis weight distribution measuring unit 42 is arranged above the fiber sheet S. The basis weight distribution measuring unit 42 is connected to a voltage control unit 43 described later, and the data signal acquired by the basis weight distribution measuring unit 42 can be transmitted to the voltage control unit 43.

As shown in FIG. 4, for example, the basis weight distribution measuring unit 42 can include a laser displacement meter 42A using infrared rays or the like. Thereby, the basis weight in the width direction of the fiber sheet S can be measured and the basis weight distribution can be analyzed. Instead of the laser displacement meter 42A, the basis weight distribution measuring unit 42 can include a camera 42B such as a CCD camera, as shown in FIG. Thereby, by analyzing using the image acquired by the camera, it is possible to analyze the basis weight distribution over the width direction of the fiber sheet S from the shading of the image and the like. In any form, it is preferable that the measurable area range of the basis weight distribution in the basis weight distribution measuring unit 42 covers the entire width direction of the fiber sheet S. The manufacturing apparatus 10 does not have to include the basis weight distribution measuring unit 42, and in this case, the basis weight distribution can be manually measured.

Returning to FIG. 1, the basis weight distribution measuring unit 42 is connected to the voltage control unit 43. The voltage control unit 43 receives the data on the basis weight distribution acquired by the basis weight distribution measurement unit 42, and repeats the data collection of the basis weight distribution in the width direction of the fiber sheet S to be conveyed. With the data collected in this way, the basis weight distribution in the width direction of the fiber sheet S being conveyed is analyzed by the voltage control unit 43. Based on the basis weight distribution in the width direction of the fiber sheet S analyzed by the voltage control unit 43, the voltage applied to each collection electrode 31 constituting the electrode group 31G in the voltage control unit 43 is determined, and the voltage thereof is determined. Is transmitted to the voltage application unit 44 connected to the voltage control unit 43.

The voltage application unit 44 applies a voltage to each collection electrode 31 constituting the electrode group 31G based on the voltage signal transmitted from the voltage control unit 43, or stops the application of the voltage. Adjusted individually. By having this configuration, the accumulated amount of fibers can be adjusted according to the height of the basis weight distribution in the width direction of the fiber sheet S measured by the basis weight distribution measuring unit 42, and as a result, the fiber sheet S can be adjusted. Basis weight distribution becomes uniform.

In the method for manufacturing a fiber sheet using the above manufacturing apparatus 10, each electrode 31 of the electrode group 31G composed of a plurality of electrodes 31 intersects the transport direction R of the transport belt 32 on the back surface of the traveling transport belt 32. The fiber sheet S is obtained by depositing the fibers spun by the electrospinning unit 20 on the front surface of the transport belt 32 under the state of being arranged along the above.

In the fiber sheet S transported by the transport belt 32, the basis weight distribution along the width direction thereof is measured by the basis weight distribution measuring unit 42. The information on the basis weight distribution measured by the basis weight distribution measurement unit 42 is transmitted to the voltage control unit 43. In the voltage control unit 43, the voltage applied to the electrode 31 arranged at the position corresponding to the portion is applied to the portion having the basis weight lower than the target basis weight value so that the accumulation of fibers in the portion increases. The signal to be adjusted is transmitted to the voltage application unit 44. At the same time, in the portion having a basis weight higher than the target average value, a signal for adjusting the applied voltage of the electrode 31 arranged at the position corresponding to the portion so as to reduce the accumulation of fibers on the portion is transmitted. It is transmitted to the voltage application unit 44. As described above, the applied voltage can be adjusted by raising or lowering the voltage or by on-off control. By performing on-off control in an extremely short cycle, it is possible to apparently control the voltage up and down. As described above, according to the present manufacturing method, the information on the basis weight distribution in the width direction of the manufactured fiber sheet S is fed back to the collecting unit 30, so that the fiber sheet has a uniform basis weight distribution in the width direction. S can be easily manufactured.

As the raw material liquid L used in the manufacturing apparatus 10, a solution in which a polymer compound capable of forming fibers is dissolved or dispersed in a solvent can be used. As the polymer compound, both a water-soluble polymer compound and a water-insoluble polymer compound are used. As used herein, the term "water-soluble polymer compound" refers to a polymer compound in water having a mass 10 times or more that of the polymer compound in an environment of 1 atm and room temperature (20 ° C. ± 15 ° C.). A polymer compound having a property of being soluble in water to the extent that 50% by mass or more of the immersed polymer compound is dissolved when a sufficient time (for example, 24 hours or more) has passed after immersion. On the other hand, the "water-insoluble polymer compound" is a polymer compound immersed in water having a mass 10 times or more that of the polymer compound in an environment of 1 atm and room temperature (20 ° C. ± 15 ° C.). A polymer compound having a property of being difficult to dissolve in water to the extent that 80% by mass or more of the immersed polymer compound does not dissolve after a sufficient time (for example, 24 hours or more) has elapsed. Inorganic particles, organic particles, plant extracts, surfactants, oils, electrolytes for adjusting the ion concentration and the like can be appropriately added to the raw material liquid L.

Examples of the water-soluble polymer compound include purulan, hyaluronic acid, chondroitin sulfate, poly-γ-glutamic acid, β-glucan, glucooligosaccharide, heparin, mucopolysaccharide such as keratosulfate, cellulose, pectin, xylan, lignin, glucomannan, and the like. Natural polymers such as galacturon, psyllium seed gum, tamarind seed gum, arabic gum, tragant gum, modified corn starch, soybean water-soluble polysaccharide, alginic acid, carrageenan, laminaran, agarose, fucoidan, methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, etc. , Partially saponified polyvinyl alcohol (when not used in combination with a cross-linking agent described later), low saponified polyvinyl alcohol, polyvinylpyrrolidone (PVP), polyethylene oxide, synthetic polymers such as sodium polyacrylate, and the like. These water-soluble polymer compounds can be used alone or in combination of two or more. Among these water-soluble polymer compounds, from the viewpoint of easy production of fibers, it is preferable to use purulan and synthetic polymers such as partially saponified polyvinyl alcohol, low saponified polyvinyl alcohol, polyvinylpyrrolidone and polyethylene oxide.

Examples of the water-insoluble polymer compound include fully saponified polyvinyl alcohol that can be insolubilized after fiber formation, partially saponified polyvinyl alcohol that can be crosslinked after fiber formation when used in combination with a cross-linking agent, and poly (N-propanoylethyleneimine) graft-dimethyl. Oxazoline-modified silicone such as siloxane / γ-aminopropylmethylsiloxane copolymer, zein (main component of corn protein), polyester, polylactic acid (PLA), polyacrylonitrile resin, acrylic resin such as polymethacrylic acid resin, polystyrene resin, Examples thereof include polyvinyl butyral resin, polyethylene teflate resin, polybutylene teflate resin, polyurethane resin, polyamide resin, polyimide resin, polyamideimide resin and the like. These water-insoluble polymer compounds can be used alone or in combination of two or more.

Other polymer compounds generally include polypropylene, polyethylene, polystyrene, polyvinyl alcohol, polyurethane, polyethylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, poly-m-phenylene terephthalate, poly-p-phenylene isofratate, and polyfurite. Vinylidene conjugation, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, vinylidene chloride-acrylate copolymer, polyacrylonitrile, polyacrylonitrile-methacrylate copolymer, polycarbonate, polyallylate, polyester carbonate, nylon, aramid, Examples thereof include polycaprolactone, polylactic acid, polyglycolic acid, collagen, polyhydroxybutyric acid, polyvinyl acetate, and polypeptides. These polymer compounds can be used alone or in admixture.

As the solvent of the raw material liquid L, water, methanol, ethanol, 1-propanol, 2-propanol, hexafluoroisopropanol, tetraethylene glycol, triethylene glycol, dibenzyl alcohol, 1,3-dioxolane, 1,4-dioxane, etc. Methyl ethyl ketone, methyl isobutyl ketone, methyl-n-hexyl ketone, methyl-n-propyl ketone, diisopropyl ketone, diisobutyl ketone, acetone, hexafluoroacetone, phenol, formic acid, methyl formate, ethyl formate, propyl formate, methyl benzoate, benzoate Ethyl acetate, propyl benzoate, methyl acetate, ethyl acetate, propyl acetate, dimethyl phthalate, diethyl phthalate, dipropyl phthalate, methyl chloride, ethyl chloride, methylene chloride, chloroform, o-chlorotoluene, p-chlorotoluene, quaternary Carbon chloride, 1,1-dichloroethane, 1,2-dichloroethane, trichloroethane, dichloropropane, dibromoethane, dibromopropane, methyl bromide, ethyl bromide, propyl bromide, acetic acid, benzene, toluene, hexane, cyclohexane, cyclohexanone, Cyclopentane, o-xylene, p-xylene, m-xylene, acetonitrile, tetrahydrofuran, N, N-dimethylformamide, pyridine and the like can be mentioned. These solvents can be used alone or in admixture.

In particular, when water is used as the solvent, it is preferable to use the following natural polymers and synthetic polymers having high solubility in water. Examples of natural polymers include purulan, hyaluronic acid, chondroitin sulfate, poly-γ-glutamic acid, β-glucan, glucooligosaccharide, heparin, keratosulfate and other mucopolysaccharides, cellulose, pectin, xylan, lignin, glucomannan and galacturonic acid. , Psyllium seed gum, tamarind seed gum, arabic gum, tragant gum, soybean water-soluble polysaccharide, alginic acid, carrageenan, laminaran, agarose, fucoidan, methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose and the like. Examples of the synthetic polymer include partially saponified polyvinyl alcohol, low saponified polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide, sodium polyacrylate and the like. These polymer compounds may be used alone or in combination of two or more. Among these polymer compounds, from the viewpoint of easy preparation of fibers, natural polymers such as purulan and synthetic polymers such as partially saponified polyvinyl alcohol, low saponified polyvinyl alcohol, polyvinylpyrrolidone and polyethylene oxide can be used. preferable.

The fiber manufactured by the manufacturing apparatus 10 of the present invention is generally 10 nm or more and 3000 nm or less, particularly 100 nm or more and 1000 nm or less when the thickness thereof is expressed by a diameter equivalent to a circle. Fiber thickness can be measured, for example, by scanning electron microscopy (SEM) observation. A fiber sheet can be obtained by randomly depositing such fibers.

The fiber manufactured by using the manufacturing apparatus 10 of the present invention can be used for various purposes as a fiber molded body in which the fiber is integrated. Examples of the shape of the molded body include a sheet, a cotton-like body, and a thread-like body. The fiber molded body may be used by laminating it with another sheet or by containing various liquids, fine particles, fibers and the like. The fiber sheet adheres to human skin, teeth, teeth, hair, skin of non-human mammals, teeth, teeth, branches, leaves, etc. for non-medical purposes such as medical purposes, cosmetic purposes, and decorative purposes. It is suitably used as a sheet to be used. It is also suitably used as a high-performance filter having high dust collection and low pressure loss, a battery separator that can be used at a high current density, a cell culture substrate having a high pore structure, and the like. The cotton-like body of the fiber is suitably used as a soundproofing material, a heat insulating material, or the like.

Although the present invention has been described above based on the preferred embodiment thereof, the present invention is not limited to the above embodiment. For example, the manufacturing apparatus and manufacturing method of the present invention can be applied to both the electric field spinning method by the solution method and the electric field spinning method by the melting method.

Further, in the manufacturing apparatus 10 of the embodiment shown in FIG. 1, the basis weight distribution in the width direction of the fiber sheet S was measured by a laser displacement meter or a CCD camera installed in the basis weight distribution measuring unit 42, but instead of this. Therefore, a worker can sample a part of the fiber sheet S and manually measure the basis weight distribution.

Hereinafter, the present invention will be described in more detail by way of examples. However, the scope of the invention is not limited to such examples.

[Comparative example: Condition 1]
Using the manufacturing apparatus 10 shown in FIGS. 1 and 2, the resin composition comprises 80% by mass of polypropylene (PP; MF650Y manufactured by PolyMirae) as a thermoplastic resin and 20% by mass of zinc stearate as an additive. The raw material liquid L of the molten resin was spun by the molten electrospinning method. The spinning conditions of the molten electric field spinning method were as follows.

-Manufacturing environment: 27 ° C, 50% RH
-Heating temperature of raw material liquid L: 250 ° C
-Discharge amount of raw material liquid L: 7.6 g / min
-Voltage applied to the charging electrode 22: -30 kV
-Voltage applied to the collection electrode 31: -20 kV
-Dimensions of the collection electrode 31: length 300 mm x width 30 mm x thickness 1 mm
-Number of collection electrodes 31 installed: 10 in the width direction with an interval of 3 mm between adjacent collection electrodes 31 (dimension meter 327 mm in the width direction).
Distance between nozzle tip 21a and electrode group 31G: 1100 mm
-The temperature of the gas ejected from the air flow injection unit 25: 450 ° C.
-Flow rate of gas ejected from the air flow injection unit 25: 200 L / min

The obtained sheet-shaped fibers were collected and cut into a length of 100 mm and a width of 300 mm in the longitudinal direction to obtain a fiber sheet. This fiber sheet was further cut so as to have a length of 100 mm × a width of 30 mm in the longitudinal direction, and a fiber sheet divided into 10 in the width direction was produced. The mass (g) of these divided fiber sheets was measured and divided by the area of the divided sheets (3000 mm ² = 0.003 m ^{2) to calculate the basis weight (g / m 2 )} of each divided sheet. FIG. 6 shows the basis weight distribution in the width direction of the fiber sheet in the comparative example (Condition 1). The average value of the basis weight distribution in the comparative example was 30 g / m ² .

[Example 1: Condition 2]
With reference to the result of the comparative example (Condition 1), the voltage was not applied to the electrodes corresponding to the positions of the width of 180 mm to 210 mm when one end in the width direction of the fiber sheet was set as the reference point (0 mm). , Spinning was carried out in the same manner as in Condition 1, and fiber sheets divided into 10 in the width direction were obtained. The position having a width of 180 mm to 210 mm in which no voltage was applied is the position having the highest basis weight as compared with the average value of the basis weight distribution under Condition 1. FIG. 7 shows the basis weight distribution in the width direction of the fiber sheet under condition 2. The average value of the basis weight distribution in Example 1 (Condition 2) was 26 g / m ² .

[Example 2: Condition 3]
With reference to the result of Example 1 (Condition 2), the voltage is not applied to the electrodes corresponding to the positions of the width of 60 mm to 180 mm and the width of 240 mm to 270 mm, and the voltage of the electrodes corresponding to the positions of the width of 180 mm to 210 mm is applied. In addition to the above, spinning was carried out in the same manner as in Condition 1 to obtain a fiber sheet divided into 10 in the width direction. The positions of widths of 60 mm to 180 mm and widths of 240 mm to 270 mm in which no voltage was applied are positions where the basis weight was higher than the average value of the basis weight distribution under Condition 2. FIG. 8 shows the basis weight distribution in the width direction of the fiber sheet under condition 3. The average value of the basis weight distribution in Example 2 (Condition 3) was 30.7 g / m ² .

〔evaluation〕
The standard deviation of the basis weight distribution having a width of 30 mm to 270 mm excluding the positions of the width 0 mm to 30 mm and the width 270 mm to 300 mm located at both ends of the fiber sheets under the conditions 1 to 3 was calculated, and the variation in the basis weight was evaluated.

When the standard deviation of the basis weight distribution of the fiber sheets produced in Examples and Comparative Examples was calculated, the standard deviation of the basis weight of the fiber sheets of Comparative Example (Condition 1) was 3.30. On the other hand, the standard deviation of the basis weight of the fiber sheet of Example 1 (Condition 2) was 2.78. The standard deviation of the basis weight of the fiber sheet of Example 2 (Condition 3) was 2.48. As described above, it can be seen that by individually controlling the voltage applied to each electrode of the electrode group based on the basis weight of the obtained fiber sheet, a fiber sheet having little variation in basis weight in the width direction can be manufactured.

10 Fiber sheet manufacturing equipment 20 Electric field spinning part 21 Nozzle 22 Charging electrode 25 Air flow injection part 30 Collection part 31 Collection electrode (electrode)
32 Conveyance belt 40 Evaluation unit 41 Take-up roll 42 Basis weight distribution measurement unit 43 Voltage control unit 44 Voltage application unit L Raw material liquid R Conveyance direction S Fiber, fiber sheet

Claims (4)

A transport belt that deposits and conveys the fibers spun by an electric field spinning device equipped with a nozzle that discharges the raw material liquid of the fibers.
A basis weight distribution measuring unit for measuring the basis weight distribution along the width direction of the fibers deposited on the transport belt, and a basis weight distribution measuring unit.
An electrode group consisting of a plurality of electrodes arranged on the back surface of the transport belt, and
An insulator arranged between each electrode of the electrode group and
A voltage application unit that applies voltage to each electrode of the electrode group, and
A fiber sheet manufacturing apparatus including a voltage control unit that individually controls the voltage applied to each electrode of the electrode group from the voltage application unit.
A voltage different from the voltage applied to the nozzle is applied to the electrode.
Each electrode of the electrode group is arranged along a direction orthogonal to the transport direction of the transport belt.
The height of the insulator is larger than the thickness of the electrode,
The insulator and the electrode are arranged at a distance from each other.
The voltage control unit individually controls the voltage applied from the voltage application unit to each electrode of the electrode group based on the basis weight distribution measured by the basis weight distribution measurement unit. manufacturing device. The fiber sheet manufacturing apparatus according to claim 1, wherein the basis weight distribution measuring unit includes a laser displacement meter. The fiber sheet manufacturing apparatus according to claim 1, wherein the basis weight distribution measuring unit includes a camera. A method for manufacturing a fiber sheet using the apparatus according to claim 1.
Spinning with an electric field spinning device on the front surface of the transport belt under the condition that each electrode of the electrode group consisting of a plurality of electrodes is arranged on the back surface of the traveling conveyor belt along the direction intersecting the transport direction of the transport belt. Deposit the fibers that have been
The basis weight distribution along the width direction of the fiber conveyed by the transfer belt is measured, and in the portion where the basis weight is lower than the target basis weight value, the deposition of the fiber in the portion is increased in the portion. The voltage applied to the electrode arranged at the corresponding position is adjusted, and the position corresponding to the portion is such that the deposition of fibers on the portion is reduced in the portion having a basis weight higher than the target average value. A method for manufacturing a fiber sheet, which adjusts the applied voltage of the electrodes arranged in the above.

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