JP4886610B2 - Method for producing electrospun nonwoven fabric - Google Patents

Description

  The present invention relates to a method for producing an electrospun nonwoven fabric. More specifically, the present invention relates to a method for producing an electrospun nonwoven fabric that can remove the solvent of the spinning dope without causing wrinkles or unevenness.

  If the fiber diameter of the fibers that make up the nonwoven fabric is small, the fiber diameter of the fibers that make up the nonwoven fabric is excellent because it has excellent performance such as separation performance, liquid retention performance, wiping performance, concealment performance, insulation performance, or flexibility. Is preferably small. As a method for producing a nonwoven fabric composed of fibers having such a small fiber diameter, a spinning solution in which a polymer is dissolved is supplied to the spinning space, and an electric field is applied to the supplied spinning solution to form a fiber, which is then stretched to obtain a fiber diameter. A so-called electrospinning method is known in which a small fiber is directly collected and made into a nonwoven fabric.

  In the case of producing a nonwoven fabric by such an electrostatic spinning method, if the number of means for supplying the spinning solution to the spinning space (for example, nozzles) is one, the supply amount of the spinning solution is small, resulting in poor productivity. Therefore, the applicant of the present application has proposed a method for increasing the productivity of the electrospun nonwoven fabric by circulating and moving a large number of nozzles in an oval shape (Patent Document 1).

JP 2006-112023 A (Claims, paragraph number 0059, etc.)

  In general, the solvent of the spinning solution remains in the nonwoven fabric formed by directly collecting fibers spun by the electrospinning method. Therefore, the solvent may have an adverse effect in the actual use. It was.

  Therefore, also in the said patent document 1, it is disclosed that it is preferable to dry before winding up the elongate nonwoven fabric formed by directly collecting the fiber spun by the electrostatic spinning method. For this reason, the electrospun nonwoven fabric was dried by passing it through a heated box in a floating state, and the solvent of the spinning stock solution was removed. As a result, unevenness of fiber dispersion occurred and the commercial value of the nonwoven fabric was significantly reduced.

  Therefore, the present inventors have considered stretching when the electrospun nonwoven fabric is dried. However, in order to stretch so as not to cause wrinkles during drying, it is necessary to stretch at a high magnification, and an electrospun nonwoven fabric having a small difference in strength between the warp direction and the transverse direction has a strength in the warp direction. It became strong and the original physical properties of the electrospun nonwoven fabric were damaged.

  The present invention has been made to solve such a problem, and without causing wrinkles or fiber dispersion unevenness, the solvent of the spinning dope is removed, and an electrostatic force having a small strength difference between the warp direction and the transverse direction is obtained. It aims at providing the method which can manufacture a spinning nonwoven fabric.

  The invention according to claim 1 of the present invention is such that “a fiber obtained by spinning a spinning stock solution containing a solvent by an electrospinning method is directly collected to form a fiber web, and then heated to a temperature higher than the boiling point of the solvent. “A method for producing an electrospun nonwoven fabric, comprising contacting a fiber web and stretching the fiber web 1.1 to 1.2 times”.

  In the invention according to claim 1 of the present invention, the solvent can be reliably removed by bringing the fiber web into contact with the roll heated to the boiling point of the solvent or more, and the degree of freedom of the fiber web can be obtained by bringing the fiber web into contact with the heating roll. The fiber web shrinkage or elongation is suppressed by stretching at a magnification of 1.1 times or more, wrinkles or fiber dispersion unevenness is not generated, and the stretching ratio is 1.2 times or less. Thus, it is possible to produce an electrospun non-woven fabric with a small difference in strength between the warp direction and the transverse direction by suppressing the fiber from being oriented in the warp direction.

  In the method for producing an electrospun nonwoven fabric of the present invention, first, fibers obtained by spinning a spinning stock solution containing a solvent by an electrospinning method are directly collected to form a fiber web. This electrostatic spinning method is a conventionally known method, in which an electric field is applied to a spinning solution supplied from a spinning solution supply unit such as a nozzle to a spinning space, whereby the spinning solution is stretched and fiberized. is there. The supply of the spinning dope from the spinning dope supply section to the spinning space can produce an electrospun nonwoven fabric with small fiber dispersion unevenness, and can produce an electrospun nonwoven fabric having a certain width and length. Moreover, it is preferable to carry out by the method disclosed in JP-A-2006-112023. That is, it is preferable to supply the spinning dope while moving the spinning dope supply unit such as a nozzle linearly (particularly in an oval shape) in the width direction of the collector. When moved linearly in this way, the moving speed of the spinning dope supply unit can be made constant, so that it is easy to produce a nonwoven fabric with small fiber dispersion unevenness. According to the electrostatic spinning method, continuous fibers having an average fiber diameter of 1 μm or less can be spun.

  The spinning dope contains a solvent, and is a solution obtained by dissolving a material that becomes a fiber base in a solvent. The material of the fiber varies depending on the use application of the electrospun nonwoven fabric and is not particularly limited. For example, polyethylene glycol, partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, polyvinyl pyrrolidone, polylactic acid, polyglycol Examples thereof include organic materials such as acid, polyacrylonitrile, polystyrene, polyamide, polyimide, polyolefin such as polyethylene and polypropylene, and inorganic materials such as quartz glass. In the case of an inorganic material, a spinnable sol solution obtained by hydrolyzing a metal alkoxide can be used as a spinning dope. Moreover, the material used as the element of a fiber does not need to be comprised from one type of material, and may be comprised from two or more types of materials.

  The solvent of the spinning dope varies depending on the material of the fiber and is not particularly limited. For example, water, acetone, methanol, ethanol, propanol, isopropanol, toluene, benzene, cyclohexane, cyclohexanone, tetrahydrofuran, dimethyl sulfoxide 1,4-dioxane, carbon tetrachloride, methylene chloride, chloroform, pyridine, trichloroethane, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, ethylene carbonate, diethyl carbonate, propylene carbonate And acetonitrile. Solvents other than those exemplified above can also be used, and mixed solvents using two or more solvents including solvents other than those exemplified can also be used.

  In the present invention, a fiber web is formed by directly collecting fibers spun by the above-described electrostatic spinning method with a collector. Although the collection body which can collect this fiber directly is not specifically limited, For example, it is a nonwoven material, a textile fabric, a knitted fabric, a net | network which consists of electroconductive materials, such as metal and carbon, or nonelectroconductive materials, such as an organic polymer. A flat plate, a drum, or a belt can be used. In some cases, a liquid such as water or an organic solvent can be used as a collector. In particular, it is preferable to use a collector having a silicone-based resin or a fluorine-based resin on the fiber collection surface and excellent in the peelability of the fiber web.

  Then, the fiber web formed by collecting with the collector is brought into contact with a roll heated to the boiling point of the above-mentioned solvent or more, and the fiber web is stretched 1.1 to 1.2 times. Manufacturing. Thus, since the fiber web is brought into contact with the roll heated to the boiling point of the solvent or higher, the solvent of the spinning dope can be reliably removed. In addition to lowering the degree of freedom of the fiber web by bringing the fiber web into contact with a heated roll, by stretching 1.1 times, fiber shrinkage or elongation due to removal of the spinning dope is suppressed, Occurrence of wrinkles and uneven fiber dispersion is suppressed. Furthermore, by setting the draw ratio to 1.2 times or less, it is possible to suppress the fiber from being oriented in the vertical direction, and to produce an electrospun nonwoven fabric with a small difference in strength between the vertical direction and the transverse direction.

  The roll is not particularly limited as long as it can be heated to the boiling point of the solvent or higher, and a metal roll can be generally used. In addition, although the roll should just be heated more than the boiling point of a solvent, it is preferable that it is heated more than the temperature 10 degreeC higher than a boiling point, and 30 degreeC higher than a boiling point so that a solvent can be removed efficiently. More preferably, it is heated above the temperature. The upper limit of the heating temperature of the roll is not particularly limited, but is preferably lower than the decomposition temperature of the material that is the basis of the fiber. The “boiling point” of the solvent in the present invention refers to a value obtained according to JIS K5601-2-3.

  The contact of the fiber web with such a heated roll is preferably performed along the surface of the roll so that the fiber web contracts or stretches and hardly generates wrinkles. In this way, when it is along the surface of the roll, the contact with the roll may be only on one side of the fiber web, or after the one side is aligned, the opposite surface may be contacted along the roll. When contacting both sides along the roll one side at a time, it is sufficient to contact either side along the roll heated above the boiling point of the solvent, and contact along the roll at the same temperature. There is no need to let them.

  In addition, when making a fiber web contact a heated roll, it may pressurize and does not need to pressurize. However, since the strength of the fiber web is low, pressing with a metal roll may damage the fiber web due to the unevenness of the metal roll, resulting in holes and tears. When pressing, an elastic roll such as a rubber roll It is preferable to pressurize with.

  Further, the contact time of the fiber web with the heating roll may be a time that can sufficiently remove the solvent, and varies depending on the material of the fiber, the basis weight of the fiber web, the solvent, the heating temperature, etc. Although it is not, it is preferable that it is 5 seconds or more.

  When brought into contact with the heated roll as described above, by rotating the roll, the fiber web can be transported without being damaged, and the effect of continuously producing the electrospun nonwoven fabric can be achieved.

  In the present invention, the fiber web is brought into contact with a heated roll, and at the same time, the fiber web is stretched by 1.1 times or more to suppress the shrinkage or elongation of the fiber by removing the solvent, and the occurrence of wrinkles and fiber dispersion unevenness Is suppressed. More preferably, the film is stretched by 1.13 times or more. On the other hand, by setting the draw ratio to 1.2 times or less, it is possible to suppress the change in fiber orientation and to manufacture an electrospun nonwoven fabric having a small difference in strength between the vertical direction and the transverse direction. More preferably, the film is stretched at 1.17 times or less. This “stretch ratio” is a value obtained by dividing the length (La) of the electrospun nonwoven fabric after stretching (after contact with the heating roll) by the length (Lb) of the fiber web before stretching (before contact with the heating roll) ( = La / Lb), for example, when the rotation speed of the heating roll is Vr and the winding speed of the electrospun nonwoven fabric is Vn, the Vn / Vr value is the draw ratio. Such stretching can be carried out, for example, by adjusting driving means (for example, a driving roll, a winding roll, etc.) disposed on the downstream side of the heating roll. In addition, when making a fiber web contact with two or more heating rolls, the rotational speed of each heating roll may be the same, and may differ.

  The removal of the solvent by such a heating roll may be continuously brought into contact with the heating roll after forming the fiber web, or after forming the fiber web and winding it once, it is unwound and brought into contact with the heating roll. Also good.

  The electrospun non-woven fabric produced by the production method of the present invention is an electrospun non-woven fabric that has no residual solvent, little wrinkles and fiber dispersion unevenness, and a small strength difference between the vertical direction and the transverse direction. Can be used for various purposes. For example, liquid, gas, or mask filter media, separators for electrochemical elements (for example, alkaline battery separators, lithium battery separators, electric double layer capacitor separators, electrolytic capacitor separators, etc.), wipers, electrolyte membrane materials It can be used for artificial skin materials, nanocapsule materials, and the like.

  EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but these do not limit the scope of the present invention. The “tensile strength” is a value measured by using an Instron type tensile tester and measuring an electrospun nonwoven fabric cut to a width of 15 mm under the conditions of a distance between chucks of 50 mm and a pulling speed of 50 mm / min. The amount of residual N, N-dimethylformamide was measured by heating a 0.003 g test piece collected from an electrospun nonwoven fabric at a temperature of 170 ° C. for 10 minutes, collecting the gas generated at that time, and measuring the mass of the gas chromatograph. It is a value measured by an analyzer (manufactured by Perkin Elmer, thermal desorption device “ATD-400”, manufactured by Shimadzu Corporation, gas chromatograph mass spectrometer “QP-5050A”).

Example 1
(1) Preparation of spinning stock solution;
A spinning stock solution (viscosity: 1200 mP · s) in which polyacrylonitrile having a weight average molecular weight of 500,000 was dissolved in N, N-dimethylformamide (boiling point: 153 ° C.) to a concentration of 10.5 mass% was prepared.

(2) Preparation of production equipment for fiber webs;
A manufacturing apparatus as shown in FIGS. 1 to 3 was prepared. That is, 17 nozzle groups 2 ₁ to 2 ₁₇ (stainless steel needle nozzles each having an inner diameter of 0.4 mm) are fixed to a chain-like support 6c at a pitch of 50 mm, and the support 6c is fixed to the first sprocket. 6a and bridging between the second sprocket 6b, nozzle groups ₂ 1 _{to 2 17} oval (diameter: 500 mm, minor axis: 100 mm) was placed. Furthermore, the drive motor 6 was attached to the first sprocket 6a.

Next, a micropump 3 (manufactured by Micropump; Micropump FC-513, pump head: 188 1 rpm = 0.17 mL type; controller unit: manufactured by Chuo Rika Co., Ltd.) is connected to the polyethylene container 1 and perfluoroalkoxy resin. connect the manufacturing tubes 1a, and connected through a rotary joint of this tube 1a in the nozzle 2 _1. Then, by connecting the nozzle 2 ₂ adjacent to the nozzle 2 ₁ by the same tube 1a, the spinning dope is to be able to supply to the nozzle 2 ₂ via the nozzle 2 _1. Similarly, the nozzle 2 ₂ and the nozzle 2 ₃ , the nozzle 2 ₃ and the nozzle 2 ₄ were connected in order by the tube 1 a so that the spinning solution could be supplied to the nozzle 2 ₁₇ .

Then, the glass cloth impregnated with polytetrafluoroethylene, and conductive particles, calcined belt-shaped collector body 5 (width: 800 mm) was grounded, it was placed directly below the nozzle group 2 ₁ to 2 _17. Then, while connecting the high voltage power supply 4 to the gear pump head of the micropump 3, the tip of the nozzle groups 2 ₁ to 2 _17, it is oriented in the direction of the belt-shaped collector body 5 as they go downward, moreover nozzle major axis direction of the endless track of the group 2 ₁ to 2 ₁₇ to coincide with the width direction of the belt-shaped collector body 5 (direction perpendicular to the moving direction), and arranged nozzle groups 2 ₁ to 2 _17. The distance between the nozzle groups ₂ 1 _{to 2 17} nozzle tip and the belt-shaped collector body 5 of the collecting surface was 40 mm.

Then, the nozzle group ₂ 1 _{to 2 17} and the belt-shaped collector body 5 made of vinyl chloride rectangular spinning container 8 (width: 1200 mm, height: 2000 mm, Depth: 2400 mm) was placed in the center of. In addition, inside the rectangular parallelepiped spinning vessel 8, a rectifying plate 9a was disposed in parallel with the upper wall surface at a position 800 mm below the upper wall surface. Also, a paper tube 7 (diameter: 80 mm, length: 800 mm) was installed at the end of the belt-shaped collector 5 in the moving direction so that the fiber web could be wound up following the belt-shaped collector 5. .

  A blower 9 (PAU-1400HDR, Apiste Co., Ltd.) having a temperature / humidity adjusting function was connected to the upper wall surface of the rectangular parallelepiped spinning vessel 8, and an exhaust fan 10 was connected to the lower wall surface of the rectangular parallelepiped spinning vessel 8.

(3) Preparation of solvent removal apparatus;
A solvent removal apparatus having a conceptual cross-sectional view shown in FIG. That is, the drive roll D1 (diameter: 80 mm, length: 450 mm) arranged for unwinding the fiber web of the paper tube 7 described above, and the fiber web unwound by the drive roll D1 on the downstream side of the drive roll D1. In addition, the heating rolls C1 and C2 (both diameters are 300 mm and the lengths are both 500 mm) that can be heat-treated one side at a time, and the electrospun nonwoven fabric from the heating rolls C2 are provided downstream of the heating rolls C1 and C2. Metal conveyance roll 20a (diameter: 60 mm, length: 650 mm) to be conveyed, NBR rubber drive roll D2 (diameter: 80 mm, length: 540 mm), and ear cut roll 21 for cutting unnecessary ends of the electrospun nonwoven fabric (Diameter: 80 mm, length: 540 mm, attached to a roll cutter (not shown)) Transport rolls 20b, 20c, and 20d (both have a diameter of 60 mm and a length of 540 mm), and contact with the take-up roll 23 on the downstream side of the transport roll 20d and press against the take-up roll 23. A pressure roll 22 (diameter: 80 mm, length: 450 mm) for winding the spinning nonwoven fabric, a winding roll 23 (diameter: 87 mm, length: 350 mm) that contacts the pressure roll 22 and winds the electrospun nonwoven fabric, and A solvent removing apparatus was prepared which was equipped with an NBR rubber drive roll D3 (diameter: 80 mm, length: 450 mm) which was in contact with the winding roll 23 and rotated the winding roll 23 to wind up the electrospun nonwoven fabric.

(4) Production of electrospun nonwoven fabric;
The put spinning solution to the container 1, said spinning dope with a micro-pump, supplied to the nozzle groups ₂ 1 _{to 2 17} via the nozzle _{2 1,} the nozzle groups ₂ 1 _{to 2 17} 180 mm / sec. The raw spinning solution is discharged from each nozzle while moving at a constant speed (discharge amount per one: 1 g / hour), and the belt-like collector 5 is moved at a constant speed (surface speed: 6 cm / min). Then, a voltage of +7 kV is applied from the high-voltage power source 4 to the spinning dope, and an electric field is applied to the discharged spinning dope to form fibers, which are accumulated on the belt-shaped collecting body 5 and have an average fiber diameter of 0. A fiber web composed of 3 μm continuous fibers was produced and wound with a paper tube 7. The tensile strength in the warp direction (longitudinal direction) and the tensile strength in the width direction (short direction) of the fiber web were 2.2 N / 15 mm width and 1.9 N / 15 mm width (later blade ratio = 1), respectively. 18). When the fiber web was manufactured, humidity control air having a temperature of 26 ° C. and a relative humidity of 23% was supplied from the blower 9 at 5 m ³ / min, and the gas exiting from the exhaust port was exhausted by the exhaust fan 10. .

  Next, the paper tube 7 is placed in the unwinding part of the solvent removing device, and the fiber web wound around the paper tube 7 is unwound by the drive roll D1 and supplied to the heating roll C1 heated to a temperature of 220 ° C. After being brought into contact with one side of the heating roll C1 for 20 seconds, it is supplied to the heating roll C2 heated to a temperature of 220 ° C., and the other side of the fiber web is brought into contact with the heating roll C2 for 20 seconds to contact the solvent. Removed to form an electrospun nonwoven fabric. The draw ratio at this time was 1.15 times.

  Then, the electrospun nonwoven fabric was supplied to the ear cut roll 21 by the action of the transport roll 20a and the NBR rubber drive roll D2, and both ends in the width direction were cut to a width of 260 mm.

Then, the electrospun nonwoven fabric is supplied to the pressing roll 22 by the transport rolls 20b, 20c, and 20d, the electrostatic spinning nonwoven fabric is pressed against the take-up roll 23 by the pressing roll 22, and the winding is rotated by the NBR rubber drive roll D3. The electrospun nonwoven fabric is supplied to the take-up roll 23 and wound up by the take-up roll 23 without generating wrinkles. The electrospun non-woven fabric (average fiber diameter: 0.3 μm, continuous fiber, basis weight: 4.4 g / m ²⁾ , Thickness: 0.024 mm, width: 260 mm, length: 50 m). The tensile strength in the warp direction (longitudinal direction) and the tensile strength in the width direction (short direction) of the electrospun nonwoven fabric are 2.6 N / 15 mm width and 1.6 N / 15 mm width (vertical length), respectively. Ratio = 1.63). Further, the amount of residual N, N-dimethylformamide in the electrospun nonwoven fabric was measured, but N, N-dimethylformamide was not detected.

(Example 2)
An electrospun nonwoven fabric (average fiber diameter: 0.3 μm, continuous fiber, basis weight: substantially the same as in Example 1 except that the temperature of the heating rolls C1 and C2 was 180 ° C. and the draw ratio was 1.13 times. 4.6 g / m ² , thickness: 0.023 mm, width: 260 mm, length: 50 m). Also in this case, the electrospun nonwoven fabric could be produced without generating wrinkles. The tensile strength in the warp direction (longitudinal direction) and the tensile strength in the width direction (short direction) of the electrospun nonwoven fabric are 2.6 N / 15 mm width and 1.7 N / 15 mm width (vertical length), respectively. Ratio = 1.53). Further, the amount of residual N, N-dimethylformamide in the electrospun nonwoven fabric was measured, but N, N-dimethylformamide was not detected.

(Example 3)
The electrospun nonwoven fabric (average fiber diameter: 0.3 μm, continuous fiber, basis weight: substantially the same as in Example 1 except that the temperature of the heating rolls C1, C2 was 160 ° C. and the draw ratio was 1.1 times. 4.8 g / m ² , thickness: 0.025 mm, width: 260 mm, length: 50 m). Also in this case, the electrospun nonwoven fabric could be produced without generating wrinkles. The tensile strength in the warp direction (longitudinal direction) and the tensile strength in the width direction (short direction) of the electrospun nonwoven fabric are 2.5 N / 15 mm width and 1.8 N / 15 mm width (vertical length), respectively. Ratio = 1.39). Further, the amount of residual N, N-dimethylformamide in the electrospun nonwoven fabric was measured, but N, N-dimethylformamide was not detected.

Example 4
An electrospun nonwoven fabric (average fiber diameter: 0.3 μm, continuous fiber, basis weight: substantially the same as in Example 1 except that the temperature of the heating rolls C1 and C2 was 220 ° C. and the draw ratio was 1.2 times. 4.2 g / m ² , thickness: 0.022 mm, width: 260 mm, length: 50 m). Also in this case, the electrospun nonwoven fabric could be produced without generating wrinkles. The tensile strength in the warp direction (longitudinal direction) and the tensile strength in the width direction (short direction) of the electrospun nonwoven fabric are 2.7 N / 15 mm width and 1.7 N / 15 mm width (length) Ratio = 1.59). Further, the amount of residual N, N-dimethylformamide in the electrospun nonwoven fabric was measured, but N, N-dimethylformamide was not detected.

(Comparative Example 1)
The electrospun nonwoven fabric (average fiber diameter: 0.3 μm, continuous fiber, basis weight: substantially the same as in Example 1 except that the temperature of the heating rolls C1, C2 was 140 ° C. and the draw ratio was 1.1 times. 4.8 g / m ² , thickness: 0.024 mm, width: 260 mm, length: 50 m). Also in this case, the electrospun nonwoven fabric could be produced without generating wrinkles, but N, N-dimethylformamide was detected from the electrospun nonwoven fabric.

(Comparative Example 2)
The electrospun nonwoven fabric (average fiber diameter: 0.3 μm, continuous fiber, basis weight: substantially the same as in Example 1 except that the temperature of the heating rolls C1, C2 was 220 ° C. and the draw ratio was 1.22 times. 4.0 g / m ² , thickness: 0.021 mm, width: 260 mm, length: 50 m). Also in this case, the electrospun nonwoven fabric could be produced without generating wrinkles. However, the tensile strength in the warp direction (longitudinal direction) of the electrospun nonwoven fabric and the tensile force in the width direction (short direction). The strengths were 2.8 N / 15 mm width and 1.4 N / 15 mm width (vertical ratio = 2), respectively, and the vertical ratio was large.

(Comparative Example 3)
Except that the temperature of the heating rolls C1 and C2 was 180 ° C. and the draw ratio was 1.08 times, an attempt was made to produce an electrospun nonwoven fabric, but wrinkles were generated. It was difficult to produce an electrospun nonwoven fabric.

(Comparative Example 4)
The fiber web produced in the same manner as in Example 1 is passed through an oven set at a temperature of 180 ° C. in a floated state (stretching ratio: 1.2 times), thereby removing the solvent and electrostatic spinning nonwoven fabric. However, wrinkles were generated and it was difficult to produce an electrospun nonwoven fabric. Therefore, although the draw ratio was set to 1.25 times, it was still difficult to produce an electrospun nonwoven fabric without generating wrinkles. Therefore, by setting the draw ratio to 1.3 times, the generation of wrinkles could be eliminated, but the tensile strength in the vertical direction (longitudinal direction) and the tensile strength in the width direction (short direction) are 2.8 N / 15 mm width and 1.2 N / 15 mm width (vertical ratio = 2.3), respectively, and an electrospun non-woven fabric with a large vertical ratio (weight per unit area: 4.2 g / m ² ) can be obtained. I could not.

  As is clear from the above examples and comparative examples, the fiber web is brought into contact with a roll heated to the boiling point of the solvent or more, and the fiber web is stretched 1.1 to 1.2 times to generate wrinkles. It was also found that the electrospun nonwoven fabric with a small difference in strength between the warp direction and the transverse direction can be produced by removing the solvent from the spinning dope.

Schematic plan view of the fiber web manufacturing apparatus in the examples 1 is a schematic cross-sectional view of the manufacturing apparatus shown in FIG. 1 is a schematic cross-sectional view of the manufacturing apparatus shown in FIG. Conceptual sectional view of solvent removal equipment

Explanation of symbols

1: container 1a: Tube 2 ₂₁ to _17: nozzle group 3: micropump 4: high voltage power supply 5: belt-shaped collector body 6: drive motor 6a: first sprocket 6b: second sprocket 6c: Chain-like support 7 : Paper tube 8: Cuboid spinning container 9: Blower 9a: Rectifying plate 10: Exhaust fan D1, D2, D3: Driving roll C1, C2: Heating roll 20a, 20b, 20c, 20d: Conveying roll 21: Ear cut roll 22: Press roll 23: Winding roll

Claims (1)

Fibers spun from a spinning stock solution containing a solvent by an electrospinning method are directly collected to form a fiber web, and then the fiber web is brought into contact with a roll heated to the boiling point of the solvent or higher. A method for producing an electrospun nonwoven fabric, which is drawn by 1 to 1.2 times.

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