JP2007092212A - Apparatus and method for producing fiber structure by electrospinning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for producing a fiber structure by an electrospinning method, more precisely, to provide the apparatus and the method for producing the fiber structure of a fiber-forming material by the electrospinning method, enabling the production of the fiber structure to be carried out safely and stably. <P>SOLUTION: The apparatus for producing the fiber structure by the electrospinning method by using at least one stage of a spinning part (A) having N<SB>h</SB>spinning holes having a cross section area A<SB>h</SB>is regulated so that the ratio A<SB>t</SB>/(A<SB>h</SB>×N<SB>h</SB>) of a cross section area A<SB>t</SB>of a pipe (B) for sending a solution containing the fiber-forming material to optional one stage of the spinning part (A<SB>N</SB>) to the total (A<SB>h</SB>×N<SB>h</SB>) of cross section areas of the spinning holes formed at one stage of the spinning part (A<SB>N</SB>) may be within the range of 1-1,000. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus and a method for producing a fiber structure by an electrospinning method. More specifically, the present invention relates to an apparatus and method for manufacturing a fiber structure of a fiber-forming substance by an electrospinning method, and a method and apparatus that can manufacture the fiber structure safely and stably.

  As a technique for spinning various fiber-forming substances, a melt-formed fiber-forming substance is spun from a nozzle, and this is cooled and solidified in the air or in a certain gas to obtain fibers. ”Or“ dry spinning method ”in which a solution containing a fiber-forming substance is spun from a nozzle and the solvent component is evaporated therefrom to obtain fibers. Similarly, the fiber-forming substance spun from the nozzle is added to the coagulation liquid. In general, a “wet spinning method” in which fibers are obtained by solidifying with a glass is known.

  In addition, the technology for producing a planar fiber structure is an application of the above-described spinning technology. In addition to the “dry method” and “wet method”, a process of drawing and opening is performed after melt spinning. "Spunbond method" to obtain a planar fiber structure, and "Meltblown method" to obtain a planar fiber structure through a drawing and opening process after blowing a high-temperature and high-pressure air stream to the melt spinning nozzle port Etc. are generally known.

  Various efforts have been made to use these spinning technology and fiber structure manufacturing technology to provide new characteristics not found in existing fibers and fiber structures. In particular, efforts are being made to impart new functions by minimizing the fiber diameter and improving the surface area per unit weight.

  However, the diameter of the fiber obtained by utilizing the above-described spinning technology and fiber structure manufacturing technology, and the diameter of the fiber constituting the fiber structure are the same diameter as existing fibers (several to several tens of μm). It is difficult to produce fibers with submicron or nanoscale diameters. In addition, the equipment used for extruding the fiber-forming substance under high pressure and cooling / solidifying the fiber structure is complicated and expensive, which hinders an increase in manufacturing cost and stable product supply.

  Therefore, as a new spinning technique, the “electrospinning method” exemplified in Patent Documents 1 and 2 has attracted attention. In this method, a fiber-forming substance-containing solution is charged positively or negatively, and is spun through a nozzle or a needle to a fiber structure deposition portion charged in the opposite polarity or grounded. Is the method. The fibrous fiber-forming substance spun from the nozzle or needle is refined under the influence of a potential gradient formed between the nozzle or needle and the fiber structure deposition portion. According to this method, a fiber having a diameter of several nm can be produced.

  On the other hand, studies on mass production technology, which is the subject of this method, are also being actively conducted. In Patent Document 3, a barrel that stores a liquid polymer material, a pump that pressurizes the liquid polymer material from the barrel, and a spinning device that injects the liquid polymer material supplied from the pump through a charged nozzle. A high-voltage generating unit for charging a liquid polymer substance, and a web depositing unit (collector) charged to a polarity different from that of the spinning unit is taught. According to this method, it is possible to produce a polymer web at high speed and in large quantities, unlike laboratory-scale production using a single needle provided for research purposes.

  However, in general, the amount of the polymer substance fed in the electrospinning method is a very small amount of several μL to several mL with respect to one spinning outlet. For example, the pipe between the barrel to the pump and the pump to the spinning unit If the inner diameter is not appropriate, the amount of pressure loss at the tip of the spinning section will be affected, and excessive dripping will occur from the spinning nozzle, or the uniformity of the resulting web will be extremely deteriorated. Such as spinning failure occurs.

  Further, there is a case where the blockage of the pipe occurs due to the polymer substance staying in the pipe for a long time. When the piping is clogged, the polymer material is not fed to the subsequent stage of these pipes and electrostatic spinning cannot be performed, and the internal pressure becomes excessive at the preceding stage of these pipes. There is a risk of causing damage to the barrel.

  In addition, the inside of the pump is charged to a high voltage via the polymer substance, causing an electrical malfunction, and there is a high possibility that the liquid feeding amount and spinning amount will become unstable, and a stable fiber structure. Adversely affects the production of Furthermore, when using a plurality of nozzles for the purpose of obtaining a fiber structure having a uniform opening, it is necessary to dispose a plurality of pumps for the purpose of stabilizing the spinning pressure and spinning amount at each nozzle. However, a pump required for this method that requires control of the amount of liquid fed to a very small range is generally expensive, and an increase in equipment cost required for this is inevitable.

  Further, in Patent Document 4, a jet flow is formed by providing a second electric field with respect to an electrostatic field where electrostatic spinning is performed, and this is electrostatically controlled to provide a plurality of spinning ports. An apparatus capable of continuously producing a fiber structure having a uniform opening by reducing the electric field interference between the spinning nozzle outlets and its method are taught.

  However, even in this method, a microflow pump system is used to feed the polymer material, and as described above, poor spinning, piping blockage due to retention of polymer material in the piping, pump failure, and equipment costs. It has not yet solved various problems such as increase.

US Pat. No. 6,106,913 US Pat. No. 6,110,590 JP 2002-201559 A International Publication No. 02/092888 Pamphlet

  The present invention relates to an apparatus and method for producing a fiber structure by an electrospinning method, and more specifically, in an apparatus and method for producing a fiber structure of a fiber-forming substance by an electrospinning method, the fiber structure is safe and stable. An object of the present invention is to provide an apparatus and a method capable of manufacturing a body.

The inventors diligently studied to solve the above-described problems, and led to the following invention.
1. An apparatus for producing a fiber structure made of a fiber-forming substance by an electrostatic spinning method using at least one spinning section (A) having N _h spinning outlets having a cross-sectional area A _h , wherein any spinning part (a _N) feeding the sum a _h · N _h of the cross-sectional area of the spinning outlet provided in _one stage, the solution containing the fiber-forming substance to the spinning unit of the any one stage (a _N) the ratio _{a t / (a h · N} h) is manufacturing equipment of the fiber structure by an electrostatic spinning method, characterized in that in the range of 1 to 1000 of the cross-sectional area _{a t} of the pipe (B) to.
2. The solution stored in at least one storage tank (C) disposed in the previous stage of the spinning section (A) is a mechanism for feeding the solution to the spinning section (A) via the pipe (B). This is due to the pressure applied to the liquid head. The manufacturing apparatus described in 1.
3. The inner diameter of the pipe (B) can be changed by the fluctuation of the pressure applied to the liquid head of the solution stored in the storage tank (C). Or 2. The manufacturing apparatus described in 1.
4). 1. Use a resin pipe for the pipe (B), and compress or relax the pipe wall in the middle of the pipe (B) at at least one location to vary the inner diameter of the pipe (B). ~ 3. The manufacturing apparatus in any one of.
5. A method for producing a fiber structure made of a fiber-forming substance by an electrostatic spinning method using at least one spinning section (A) having N _h spinning outlets having a cross-sectional area A _h , wherein any spinning part (a _N) feeding the sum a _h · N _h of the cross-sectional area of the spinning outlet provided in _one stage, the solution containing the fiber-forming substance to the spinning unit of the any one stage (a _N) method for producing a fiber structure by electrospinning method, wherein the pipe ratio _{a t / (a h · N} h) of the cross-sectional area _{a t} of (B) is in the range of 1 to 1000 to.
6). The method of feeding the solution to the spinning section (A) via the pipe (B) is the solution stored in at least one storage tank (C) disposed in the preceding stage of the spinning section (A). 4. It is due to the pressure applied to the liquid head. The manufacturing method as described in.
7). 4. The inner diameter of the pipe (B) is changed by a change in pressure applied to the liquid head of the solution stored in the storage tank (C). Or 6. The manufacturing method as described in.
8). 4. A resin pipe is used for the pipe (B), and the inner wall of the pipe (B) is changed by compressing or relaxing the pipe wall in the middle of the pipe (B) at at least one place. ~ 7. The manufacturing method in any one of.

  By utilizing the above-described apparatus and method for producing a fiber structure by the electrostatic spinning method, liquid feeding of the fiber-forming substance-containing solution to the spinning part, and formation of the fiber structure in the spinning part Stabilization is possible, and a fiber structure having uniform properties can be obtained. Moreover, since there is no mechanical device having a drive unit that is charged to the applied high voltage, not only can the manufacturing process be simplified, but also malfunction and danger of the mechanical device due to the applied voltage can be avoided. Since the associated work can be eliminated, safe manufacturing can be performed economically.

The production apparatus and method of the present invention will be described in detail below.
FIG. 1 is a diagram schematically illustrating a fiber structure manufacturing apparatus according to an embodiment of the present invention. 2 is a schematic view of a spinning nozzle spinning surface as seen from a surface on which a fiber-forming substance-containing solution is spun, and FIG. 3 is a schematic diagram of a side surface of the spinning nozzle. . Hereinafter, the present invention will be described in detail with reference to these drawings, but the scope of the present invention is not limited thereby.

  In the apparatus of the present invention, as shown in FIG. 1, a solution storage tank 1 capable of storing a fiber-forming substance-containing solution is disposed in the spinning section (A), that is, the front stage of the spinning nozzle 2, and the storage tank 1 and the storage tank 1 The nozzles 2 are connected by the above-described piping (B), that is, the liquid feeding piping 9. The nozzle 2 is connected to the high voltage generator 3 by electrical wiring, and the solution filled in the nozzle 2 can be charged with a high voltage together with the nozzle 2. A counter electrode 8 is disposed on the opposite side of the substrate 7 on which the fiber structure is deposited, and can be charged to the opposite polarity to the voltage applied to the nozzle 2 or grounded. It has a structure. The substrate 7 is unwound from the unwinding roll 4, passed through the free roll 5, and wound up by the winding roll 6.

  Further, depending on the conveyance speed of the base material and the desired basis weight of the fiber structure, it is possible to provide a plurality of spinning ports 10 as shown in FIG. It is effective for uniform structure and efficient production. In the present invention, it is assumed that a spinning nozzle having a plurality of spinning ports 10 as shown in FIG. 2 is used, but the number and arrangement thereof and the shape of the nozzle 2 are as shown in the schematic diagram of FIG. It is not limited.

Furthermore, the tip shape of the spout 10 of the nozzle 2 may be a hollow inverted conical shape as illustrated in FIG. 3, but may be a cylindrical shape, a hollow frustoconical shape, a hollow square shape, etc. Various shapes can be illustrated and are not limited by the schematic shown in FIG.
Further, the connecting portion between the pipe 9 and the nozzle 2 can be the center of the side surface in addition to the center of the upper surface of the nozzle 2 as illustrated in FIGS. 2 and 3. It is not limited by the schematic shown in FIG.
The fiber-forming substance-containing solution is fed from the solution storage tank 1 to the spinning section (A), that is, the spinning nozzle 2 through the pipe (B), that is, the liquid feeding pipe 9.

  Examples of the fiber-forming substance used in the present invention include polypropylene, polyethylene, polystyrene, polyethylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, poly-m-phenylene terephthalate, poly-p-phenylene isophthalate, polyfluoride. Vinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, polyvinylidene chloride-acrylate copolymer, polyacrylonitrile, polyacrylonitrile-methacrylate copolymer, polycarbonate, polyarylate, polyester carbonate, nylon, aramid, Examples include polycaprolactone, polylactic acid, polyglycolic acid, collagen, polyhydroxybutyric acid, polyvinyl acetate, and polypeptide Can, at least one selected from these are used, but the invention is not particularly limited thereto.

  Examples of the solvent used in the present invention include methanol, ethanol, 1-propanol, 2-propanol, hexafluoroisopropanol, tetraethylene glycol, triethylene glycol, dibenzyl alcohol, 1,3-dioxolane, 1,4-dioxane, 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, benzoic acid 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, chloroform, carbon tetrachloride, 1,1-dichloroethane, 1,2-dichloroethane, trichloroethane, dichloropropane, dibromoethane, dibromopropane, methyl bromide, ethyl bromide, bromide Examples include propyl, acetic acid, benzene, toluene, hexane, cyclohexane, cyclohexanone, cyclopentane, o-xylene, p-xylene, m-xylene, acetonitrile, tetrahydrofuran, N, N-dimethylformamide, pyridine, water and the like. At least one selected from these is used, but is not particularly limited thereto.

It is also possible to mix an inorganic solid material in the fiber-forming substance and the solvent described above. Examples of the inorganic solid material include oxides, carbides, nitrides, borides, silicides, fluorides, sulfides, etc., but oxides are preferably used from the viewpoint of heat resistance and workability. .
Examples of the oxide include Al ₂ O ₃ , SiO ₂ , TiO ₂ , Li ₂ O, Na ₂ O, MgO, CaO, SrO, BaO, B ₂ O ₃ , P ₂ O ₅ , SnO ₂ , ZrO ₂ , K. _{2 O, Cs 2 O, ZnO} , Sb 2 O 3, As 2 O 3, CeO 2, V 2 O 5, Cr 2 O 3, MnO, Fe 2 O 3, CoO, NiO, Y 2 O 3, Lu 2 O ₃ , Yb ₂ O ₃ , HfO ₂ , Nb ₂ O _{5 and the} like can be exemplified, and at least one selected from these can be used, but is not particularly limited thereto.

  Furthermore, although at least one storage tank 1 is provided, the pipes 9 and the nozzles 2 corresponding to the number of the storage tanks 1 are not necessarily provided. Usually, one storage tank 1 is provided. On the other hand, two or more pipes 9 and nozzles 2 are arranged. Not only the properties of the solution, the production amount and properties of the desired fiber structure, but also the amount of the solution stored in the storage tank 1 is restricted by the operation method of the device, for example, depending on the storage amount The quantity of the storage tank 1, nozzle 2, and pipe 9 must be optimized.

When the solution is sent to any one stage of the spinning section (A _N ), that is, any one stage of the nozzle 2, the solution is equally distributed to the plurality of spinning outlets 10 within the arbitrary nozzle 2, From the storage tank 1 to the entire spinning outlet 10 of the arbitrary nozzle 2 is filled with the solution. By turning on the power source of the high voltage generator 3 and the driving power source of the take-up roll 6 in this state, the fiber structure of the fiber-forming substance can be obtained on the base material 7 that moves continuously.

The number N _h of the spinning ports 10 included in any one stage of the nozzle 2 and the cross-sectional area A _h of each spinning port 10 are the properties of the fiber-forming substance, the production amount and properties of the desired fiber structure, and the like. Determined by. In particular the amount of these two products A _h · N _h numbers represents the sum of the cross-sectional area of the spinning outlet 10 any one stage of the nozzle 2 has, the solution spun from the arbitrary nozzle 2 It is a numerical value with a strong correlation.

On the other hand, the cross-sectional area A _t of the pipe (B), i.e. liquid feed pipe 9 for feeding the solution to any one stage of the nozzle 2, the amount of the solution to be fed to the arbitrary nozzle 2 It is a strongly correlated number. Thus, the ratio _A t _/ a spinning outlet cross-sectional area of any one stage of the nozzle 2 already described total _{A h} · _N h and cross-sectional area _{A t} of the pipe 9 _{(A h} · _N h) is stable This is a very important numerical value when considering the solution feeding required for the production of the fiber structure and the spinning from the arbitrary nozzle 2.

  When the numerical value becomes excessively large, the back pressure applied to the arbitrary nozzle 2 becomes excessive, and the supply of the solution to the arbitrary nozzle 2 becomes excessive, so that the solution forms a fiber structure. Without reaching droplets, the droplets reach the substrate 7 and the properties of the resulting fiber structure are remarkably deteriorated. On the other hand, when the value is small, not only is the solution fed to the arbitrary nozzle 2 inadequate and the formation of the fiber structure becomes intermittent, but also the tip of the arbitrary nozzle 2 Since the solution is solidified, as described above, the back pressure applied to the arbitrary nozzle 2 becomes extremely excessive, and in the worst case, there is a risk of causing damage to the solution storage tank 1 or the liquid feeding pipe 9. .

Therefore, the fiber structure production apparatus and the fiber structure production method according to the present invention use at least one stage of the spinning section (A) having N _h spinning outlets having a cross-sectional area A _h , that is, the spinning nozzle 2. An apparatus and a method for producing a fiber structure made of a fiber-forming substance by an electrostatic spinning method, in which one spinning stage (A _N ), that is, spinning provided in any one stage of the nozzle 2 is provided. the total a _h · N _h of the cross-sectional area of the outlet, a solution pipe for feeding a containing the fiber-forming substance on the arbitrary nozzle 2 (B), i.e. the cross-sectional area a _t of the liquid feed pipe 9 The ratio A _t / (A _h · N _h ) is in the range of 1 to 1000.

That the ratio _{A t / (A h · N} h) of the spinning outlet cross-sectional area of any one stage of the nozzle 2 Total _{A h} · _N h and cross-sectional area _{A t} of the pipe 9 and the range described above Thus, the problems described above that inhibit the formation of a stable fiber structure are solved, and a fiber structure having uniform properties can be obtained.

  Further, in the fiber structure manufacturing apparatus and method of the present invention, a mechanism for feeding the solution to the spinning section (A), that is, the nozzle 2 through the pipe (B), that is, the liquid feeding pipe 9, This is due to the pressure applied to the liquid head of the solution stored in the solution storage tank 1, that is, at least one storage tank (C) disposed in the preceding stage of the spinning section (A).

  Generally, in the electrostatic spinning method, in an electrostatic field generated by applying a high voltage to a fiber-forming substance-containing solution, an electric attractive force generated in the electrostatic field is formed at the tip of the spinning outlet 10 in the spinning nozzle 2. A method of obtaining a fiber structure by becoming larger than the surface tension of the droplet of the solution to be held and spinning the solution from the tip of the spinning outlet 10. Therefore, in order to continuously spin the solution and obtain a fiber structure stably, droplet formation / holding at the tip of the spinning outlet 10 can be an important requirement.

  On the other hand, in the conventional spinning method, when the solution consumed by the nozzle 2 is replenished, a method of feeding the solution using a pump having a high discharge pressure is employed. In the electrospinning method, a pump that can feed a very small amount of the solution is often used. However, in these methods, since the solution is forcibly fed, it is extremely difficult to form a droplet that can be held at the tip of the spinning outlet 10 in the nozzle 2. If droplet formation of the solution cannot be confirmed at the tip of the spinning outlet 10 due to insufficient liquid feeding, the surface tension of the solution becomes excessive with respect to the electric attractive force generated in the electrostatic field. The solution is not spun. Further, when the liquid feeding becomes excessive, the liquid droplets are not held at the tip of the spinning outlet 10, and the liquid droplets reach the substrate 7, and the properties of the obtained fiber structure are remarkably deteriorated.

In addition, the above-described pumps often generate unique pulsations due to the mechanism of the liquid feeding operation. Due to the pulsation, the amount of the solution delivered per unit time changes although it is extremely small, so in electrospinning that handles a very small amount of spinning, the effect on the amount of spinning is enormous. .
Therefore, in the present invention, the mechanism for feeding the solution to the nozzle 2 via the pipe 9 is provided at the liquid head of the solution stored in at least one storage tank 1 disposed in the previous stage of the nozzle 2. This is due to the pressure.

  According to this method, various problems caused by using a pump, such as unintentional droplet formation due to forced liquid feeding and fluctuations in the liquid feeding volume due to pulsation, are eliminated, so that the fiber structure can be manufactured stably. As well as the equipment costs for the pump and its peripherals.

  Furthermore, in the manufacturing apparatus and method of the fiber structure of the present invention, the pipe (B), that is, the liquid feed is caused by the fluctuation of the pressure applied to the liquid head of the solution stored in the storage tank (C), that is, the solution storage tank 1. The inner diameter of the pipe 9 is changed.

  As the fiber structure is manufactured, the amount of the solution stored in the storage tank 1 decreases. As the solution decreases, the pressure applied to the liquid head of the solution also decreases. When a plurality of the storage tanks 1 are arranged and the amount of the solution that can be stored in each of the storage tanks 1 is small, the amount of decrease in pressure applied to the liquid head of the solution is small, and the effect on the liquid feeding of the solution However, when the amount of the solution stored in the storage tank 1 increases, the pressure applied to the liquid head due to the decrease in the solution becomes serious.

In order to form and hold the droplet of the solution at the tip of the spinning outlet 10 in the nozzle 2 as described above, the amount of pressure loss at the spinning outlet 10 is made constant over time while maintaining the properties of the solution. It is also necessary to keep. If the pressure applied to the liquid head due to a decrease in the solution is reduced, if the cross-sectional area A _h of the cross-sectional area A _t and the spinning outlet 10 of the liquid feed pipe 9 is constant, the pressure loss in the spinning outlet 10 previously described The amount decreases over time. This becomes a factor which produces the same problem as the above-mentioned problem recognized by the liquid feeding using a pump, and inhibits the stable manufacture of a fiber structure remarkably.

  Therefore, in the present invention, the inner diameter of the pipe 9 is changed by a change in pressure applied to the liquid head of the solution stored in the storage tank 1. In the initial stage of production in which the pressure applied to the liquid head is relatively large, the diameter of the pipe is reduced for the purpose of increasing the amount of pressure loss in the middle of the pipe 9, and on the contrary, the pressure applied to the liquid head is relatively low in the late stage For the purpose of reducing the amount of pressure loss in the middle of the pipe 9 from the initial stage of manufacture, the pipe diameter once reduced is expanded to the original pipe diameter at the maximum.

  According to this method, the amount of pressure loss at the tip of the spinning outlet 10 becomes substantially constant over time regardless of the pressure fluctuation applied to the liquid head of the solution, and electrostatic spinning is performed at the tip of the spinning outlet 10. It is possible to form and hold a droplet that is optimal for performing the above. This is very effective for continuous production of a stable fiber structure.

  In the fiber structure manufacturing apparatus and method of the present invention, a resin pipe is used for the pipe (B), that is, the liquid feeding pipe 9, and at least one portion of the pipe wall in the middle of the pipe 9 is compressed or relaxed. Thus, the inner diameter of the pipe 9 is changed.

  The simplest method for changing the inner diameter of the pipe 9 described above is to install a flow rate adjusting valve in the middle of the pipe 9. Opening and closing the valve is synonymous with changing the inner diameter of the pipe 9, whereby the amount of pressure loss in the pipe 9 can be adjusted.

  However, according to this method, in order to perform minute flow rate adjustment, a valve having a wide adjustable range and high adjustment accuracy needs to be installed in the middle of the pipe 9. In general, such a valve is expensive and has poor maintainability, and an increase in equipment and maintenance costs is inevitable. Further, the valve also has a structural problem, and there is a risk that the solution is not sent to the spinning nozzle 2 and partly stays. This adversely affects the properties of the solution and further hinders the production of a uniform fiber structure.

Therefore, in the present invention, a resin pipe is used for the pipe 9 and the inner diameter of the pipe 9 is changed by compressing or relaxing at least one portion of the pipe wall in the middle of the pipe 9.
Here, the resin used as the material of the pipe 9 includes a fiber-forming substance that is excellent in elasticity and elasticity, such as polypropylene, polyethylene, silicon, and fluorine resin, and is generally produced as a pipe material. The selection can be made based on the properties of the solution, but is not limited thereto.

  In addition, as a method of compressing or relaxing the middle of the pipe 9, a roller-shaped clamp is disposed to adjust the throttle amount of the clamp, or a molding pinch cock is disposed, and the knob of the cock is Connect to the driving reciprocating cylinder, adjust the pinch cock opening by reciprocating movement of the cylinder, arrange the Hoffman pinch cock, connect the screw part of the cock to a rotary motor that can rotate forward and backward, Although the method etc. which adjust a pinch cock opening degree by rotation of the said motor can be illustrated, it does not specifically limit to these.

  According to this method, it is possible to adjust the minute flow rate by a simple method. That is, an excessive equipment cost is not required, and adjustment of the pressure loss amount in the middle of the pipe 9 is possible in a minute range. Therefore, the fluctuation of the pressure loss amount with time at the spinning outlet 10 in the spinning nozzle 2 is changed. Is minimized, and a continuous production of a stable fiber structure is possible.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.
[Example 1]
66 g of L-polylactic acid was charged into a glass container (internal volume: 1000 mL) equipped with a stirrer with an anchor blade made of SUS304, and 534 g of methylene chloride was further charged. After sealing the open part of the container, it was stirred in a 37 ° C. warm water bath, and it was confirmed that L-polylactic acid was uniformly dissolved in the aforementioned solvent. The container was opened, and the entire amount thereof was put into a Teflon (registered trademark) solution storage tank 1 (internal volume: 1000 mL each) of the apparatus illustrated in FIG.

The Teflon (registered trademark) spinning nozzle 2 illustrated in FIG. 2 (schematic dimensions: W300 × L100 × H40 mm, discharge port number N _h : 12, discharge port cross-sectional area A _h : 0.070 mm ²⁾ outlet cross-sectional area total ^{_{a h · N h: 0.84mm 2}} ) was disposed, the nozzle 2 and the storage tank 1 between silicon liquid feed pipe 9 (cross-sectional area _a t: connected by 28mm ²⁾ _{(a t} / (A _h · N _h ) = 33). The solution started to be fed to the nozzle 2 by the pressure applied to the liquid head of the solution stored in the storage tank 1. An electrical wiring was connected to an electrical connection terminal disposed on the side surface of the nozzle 2, and this was connected to the high voltage generator 3. Further, a polyester nonwoven fabric is used as the base material 7, the roll-shaped base material 7 is attached to the unwinding roll 4, and after being manually guided to the free roll 5 and then to the take-up roll 6, the transport speed of the base material 7 is The rotational speed of the winding roll 6 was set to 1.0 m / min, and the drive power was turned on. At the same time, the power source of the high voltage generator 3 was turned on to start manufacturing the fiber structure. The solution began to be spun from the spinning surface of the nozzle 2, and a planar fiber structure was obtained on the substrate 7.

  After leaving for 30 minutes, the power source of the high-voltage generator 3 and the driving power source of the take-up roll 6 were stopped, and the roll-shaped substrate 7 and the fiber structure were collected from the take-up roll 6. The fiber structure was peeled off from the base material 7, and 1 cm of each fiber structure was cut from 20 arbitrary locations, and the thickness of all of these was measured with an offline film thickness meter. Furthermore, all these surface states were observed with a scanning electron microscope. As a result, the thickness at each measurement location was all within ± 2.0 μm with respect to the average thickness of the fiber structure: 22 μm. Moreover, the average value of the fiber diameter in each measurement location was all within ± 50 nm with respect to the average value of the fiber diameter of all measurement locations: 265 nm.

[Example 2]
As the nozzle 2 to be used, schematic dimensions: W210 × L60 × H40 mm, number of discharge ports N _h : 6, discharge port cross-sectional area A _h : 0.20 mm ² , total discharge port cross-sectional area A _h · N _h : 1.2 mm ² This was carried out in the same manner as in Example 1 except that a spinning nozzle was used (A _t / (A _h · N _h ) = 23). As a result, the thickness at each measurement location was all within ± 3.0 μm with respect to the average thickness of the fiber structure: 31 μm. Moreover, the average value of the fiber diameter in each measurement location was all within ± 50 nm with respect to the average value of the fiber diameter of all measurement locations: 291 nm.

[Example 3]
As liquid feed pipe 9 to be used, the cross-sectional area _A t: except using silicon tubing 201 mm ² was carried out in the same manner as in Example _{1 (A t / (A h} · N h) = 239). As a result, the thickness at each measurement location was all within ± 2.5 μm with respect to the average thickness of the fiber structure: 27 μm. Moreover, the average value of the fiber diameter in each measurement location was all within ± 50 nm with respect to the average value of the fiber diameter of all measurement locations: 269 nm.

[Example 4]
The Hoffman pinch cock is arranged in the middle of the pipe 9, the screw part of the cock is connected to a rotary motor that can rotate forward and reverse, and the device is improved so that the pinch cock opening can be adjusted by the rotation of the motor. did. In addition, since the pressure applied to the liquid head of the solution stored in the storage tank 1 can be calculated from the liquid level of the stored solution, a liquid level gauge is additionally provided in the storage tank 1. The opening degree of the pinch cock described above was finely adjusted according to the degree of decrease in the indicated value of the liquid level gauge. As a result of carrying out in the same manner as Example 1 except for this, the thickness at each measurement location was all within ± 2.0 μm with respect to the average value of the thickness of the fiber structure: 19 μm. Moreover, the average value of the fiber diameter in each measurement location was all within ± 50 nm with respect to the average value of the fiber diameter of all measurement locations: 301 nm.

[Comparative Example 1]
As liquid feed pipe 9 to be used, the cross-sectional area _A t: except using silicon tubing 1257Mm ² was carried out in the same manner as in Example _{2 (A t / (A h} · N h) = 1047). As a result, although the formation of the fiber structure was confirmed, dripping of the solution occurred at the tip of the nozzle 2, the droplet reached the substrate 7, and the appearance of the resulting fiber structure was remarkably increased. It was detrimental.

[Comparative Example 2]
As the nozzle 2 to be used, schematic dimensions: W210 × L80 × H40 mm, number of discharge ports N _h : 6, discharge port cross-sectional area A _h : 5.3 mm ² , total discharge port cross-sectional area A _h · N _h : 31.8 mm ² except using the spinning nozzle it is was performed in the same manner as in example _{1 (a t / (a h} · N h) = 0.88). As a result, although formation of the fiber structure was confirmed at the beginning of production, blockage due to solidification of the solution was confirmed at the discharge port 10 of the nozzle 2 after several minutes, and formation of the fiber structure was not confirmed thereafter.

It is the schematic which shows an example of the manufacturing apparatus in this invention. It is the schematic of the said spinning nozzle spinning surface which looked at the spinning nozzle of arbitrary 1 steps | paragraphs of the manufacturing apparatus in this invention from the surface where a fiber-forming substance containing solution spins. It is the schematic of the spinning nozzle side surface of the manufacturing apparatus in this invention.

Explanation of symbols

1. 1. Solution storage tank 2. Spinning nozzle 3. High voltage generator 4. Unwinding roll Freeroll 6. 6. Winding roll Base material 8. Counter electrode 9. Feeding pipe (cross-sectional _{area: A} t)
10. Spinning outlet (cross-sectional area: A _h , number of units: N _h )

Claims (8)

An apparatus for producing a fiber structure made of a fiber-forming substance by an electrostatic spinning method using at least one spinning section (A) having N _h spinning outlets having a cross-sectional area A _h , wherein any spinning part (a _N) feeding the sum a _h · N _h of the cross-sectional area of the spinning outlet provided in _one stage, the solution containing the fiber-forming substance to the spinning unit of the any one stage (a _N) the ratio _{a t / (a h · N} h) is manufacturing equipment of the fiber structure by an electrostatic spinning method, characterized in that in the range of 1 to 1000 of the cross-sectional area _{a t} of the pipe (B) to.   The solution stored in at least one storage tank (C) disposed in the previous stage of the spinning section (A) is a mechanism for feeding the solution to the spinning section (A) via the pipe (B). The manufacturing apparatus according to claim 1, which is caused by pressure applied to the liquid head.   The manufacturing apparatus according to claim 1 or 2, wherein an inner diameter of the pipe (B) can be changed by a change in pressure applied to a liquid head of the solution stored in the storage tank (C).   The resin pipe is used for the pipe (B), and the inner wall of the pipe (B) is changed by compressing or relaxing the pipe wall in the middle of the pipe (B) at least at one place. 4. The manufacturing apparatus according to any one of 3. A method for producing a fiber structure made of a fiber-forming substance by an electrostatic spinning method using at least one spinning section (A) having N _h spinning outlets having a cross-sectional area A _h , wherein any spinning part (a _N) feeding the sum a _h · N _h of the cross-sectional area of the spinning outlet provided in _one stage, the solution containing the fiber-forming substance to the spinning unit of the any one stage (a _N) method for producing a fiber structure by electrospinning method, wherein the pipe ratio _{a t / (a h · N} h) of the cross-sectional area _{a t} of (B) is in the range of 1 to 1000 to.   The method of feeding the solution to the spinning section (A) via the pipe (B) is the solution stored in at least one storage tank (C) disposed in the preceding stage of the spinning section (A). The manufacturing method of Claim 5 which is based on the pressure concerning the liquid head.   The manufacturing method according to claim 5 or 6, wherein the inner diameter of the pipe (B) is changed by a change in pressure applied to a liquid head of the solution stored in the storage tank (C).   The resin pipe is used for the pipe (B), and the inner wall of the pipe (B) is changed by compressing or relaxing the pipe wall in the middle of the pipe (B) at least at one place. 8. The production method according to any one of 7 above.

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