JP2005273067A - Method for producing nonwoven fabric by electric charge-induced spinning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optimum charging method of an accumulating part for accumulating a fiber structure obtained by electric charge-induced spinning, a drying method using the accumulating part having a shape suitable for drying the fiber structure, and a method for continuously conveying a nonwoven fabric to safely mass-produce the nonwoven fabric having uniform shape and characteristics by using an electric charge-induced spinning method. <P>SOLUTION: The method for producing the nonwoven fabric by the electric charge-induced spinning method involves inserting a flat structure (C) having many holes between a spinning part (A) and an electrode (B), and accumulating the fiber structure comprising a macromolecular compound on the surface of the structure (C) in the method for producing the nonwoven fabric by jetting a macromolecular compound solution from the spinning part (A) for spinning the solution containing the positively or negatively charged macromolecular compound to the plate-shaped electrode (B) charged in the polarity inverse to that of the spinning part (A), and accumulating the fiber structure composed of the macromolecular compound. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a nonwoven fabric. More specifically, the present invention relates to a method for producing a non-woven fabric of a polymer compound by a charge-induced spinning method, a charging method for a deposited portion where the non-woven fabric is obtained, and a method for continuously conveying the non-woven fabric.

  As a technique for spinning various polymer compounds, a melt-spinning method is used in which molten polymer compounds are spun from a nozzle and cooled and solidified in the air or in a certain gas to obtain fibers. `` Spinning spinning method '' in which a solution containing a polymer compound is spun from a nozzle and the solvent component is evaporated therefrom to obtain fibers, and the fibrous polymer compound spun from the nozzle is solidified in a coagulation liquid. The “wet spinning method” in which fibers are obtained by causing them to be generally known.

  In addition, the technology for producing nonwoven fabrics applies the above-mentioned spinning technology. In addition to the “dry method” and “wet method”, “spunbond” is used to obtain nonwoven fabrics through melt spinning and drawing / opening processes. In general, there are known “method” and “melt blown method” in which a nonwoven fabric is obtained by blowing and opening a fibrous polymer compound by blowing a high-temperature and high-pressure air stream to a melt spinning nozzle port.

  Various efforts have been made to utilize these spinning technology and nonwoven fabric manufacturing technology to provide new characteristics not found in existing fibers and nonwoven fabrics. 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 using the above-described spinning technology and nonwoven fabric manufacturing technology, and the diameter of the fiber constituting the nonwoven fabric 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, facilities used for extruding a polymer compound under high pressure and cooling / solidifying a fibrous polymer compound are complicated and expensive, which hinders an increase in manufacturing cost and stable product supply.

  Thus, as a new spinning technique, “charge-induced spinning method”, which is also taken up in US Pat. No. 6,106,913 (Patent Document 1) and US Pat. No. 6,110,590 (Patent Document 2), is attracting attention. This method is a method in which a solution containing a polymer compound is charged positively or negatively, and spun through a nozzle or a needle to a fibrous polymer compound deposition portion charged in the opposite polarity. is there. The fibrous polymer compound having one polarity is thinned by an electric repulsive force in the fiber while reaching the 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 Japanese Patent Application Laid-Open No. 2002-201559 (Patent Document 3), a barrel for storing a liquid polymer substance, a pump for supplying a liquid polymer substance under pressure from the barrel, and a liquid polymer substance supplied from the pump There is provided a polymer web manufacturing apparatus comprising a spinning section for injecting a liquid through a charged nozzle, a high voltage generating section for charging a liquid polymer substance, and a web deposition section (collector) charged to a polarity different from that of the spinning section. 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 this method, it is structurally difficult to charge only the conveyor belt, and it is necessary to charge all the portions where the polymer web is deposited and transported. That is, it is necessary to place the web depositing part (collector) including the spinning part under a high voltage, and not only a uniform charge distribution is difficult, but also the solvent vapor is mixed, so the danger is extremely high. The number of charged parts is a problem directly related to the presence or absence of danger, and a device to reduce the charged parts is desired. In order to solve this problem, another high voltage generator is installed, and a method of charging the spinning unit and the web depositing unit separately is taught. However, the high voltage generator is very expensive and the equipment cost is low. An increase is inevitable.

  In addition, when performing hot air drying for the purpose of removing the solvent contained in the polymer web, the conveyor belt for the purpose of depositing and transferring the polymer web inhibits the circulation of the hot air, and remarkably deteriorates the drying efficiency.

  In addition, JP 2002-249966 A (Patent Document 4) teaches a similar mass production method. This method comprises a step of producing a polymer solution, a step of spinning the polymer solution by a charge-induced spinning method, and a step of obtaining a polymer web on the web depositing portion. By controlling the temperature, it is possible to mass-produce a polymer web having a desired fiber diameter.

  However, even in this method, there are problems with the above-described charging method and drying method, and it is difficult to provide a product having a uniform shape and characteristics.

US Pat. No. 6,106,913 US Pat. No. 6,110,590 JP 2002-201559 A JP 2002-249966 A

  In order to mass-produce non-woven fabric having a uniform shape and characteristics at high speed and safely by using the charge-induced spinning method, an optimal charging method for the depositing portion for depositing the fiber structure obtained by spinning, and the fiber structure An object of the present invention is to provide a drying method using a depositing portion having a shape suitable for drying and a method for continuously conveying a nonwoven fabric.

  The inventors have intensively studied in order to solve the above-mentioned problems, a spinning part (A) for spinning a solution containing a positively or negatively charged polymer compound, and a polarity opposite to that of the part. By inserting the structure (C) in which a plurality of holes are arranged at regular intervals between the plate-like electrode (B) charged to a high level, the polymer compound is excellent on the surface of the structure (C) It has been found that a nonwoven fabric having a uniform shape and characteristics can be continuously obtained while being deposited while maintaining proper order. Further, it has been found that the present invention can greatly contribute to the reduction of the equipment cost by reducing the number of charged portions of the non-woven fabric accumulation portion.

  That is, the first aspect of the present invention is a method for producing a nonwoven fabric of a polymer compound by a charge dielectric spinning method, and a spinning section (A) for spinning a solution containing a polymer compound positively or negatively charged; A planar structure (C) in which a plurality of holes are arranged at regular intervals is inserted between plate-like electrodes (B) charged to a polarity opposite to that of the portion, and the surface of the structure (C) The present invention relates to a method for producing a nonwoven fabric, characterized in that a polymer compound is deposited thereon to obtain a nonwoven fabric. A second aspect of the present invention is characterized in that the deposited portion formed from the structure (C) has a strip shape, and the obtained nonwoven fabric is continuously conveyed by continuously moving the strip-shaped deposited portion. This relates to the manufacturing method of the first invention. 3rd of this invention is related with the manufacturing method of the said 1st and 2nd invention characterized by the said structure (C) being a network structure. 4th of this invention is related with the manufacturing method of the said 3rd invention characterized by the opening of the said mesh-shaped structure being the range of 5 micrometers-30 mm.

Further, the present invention is a production apparatus for producing a nonwoven fabric of a polymer compound by a charge dielectric spinning method,
(1) a spinning section (A) for spinning a solution containing a polymer compound positively or negatively charged;
(2) having a plate-like electrode (B) that can be charged to a polarity opposite to that of the portion;
(3) A planar structure (C) having a plurality of holes for depositing a fiber structure made of the polymer compound is inserted between the spinning part (A) and the electrode (B). The present invention relates to a characteristic manufacturing apparatus.

  In a method for producing a nonwoven fabric of a polymer compound by the charge dielectric spinning method, a spinning part (A) for spinning a solution containing a polymer compound positively or negatively charged and a polarity opposite to that of the part By inserting the structure (C) in which a plurality of holes are arranged at regular intervals between the charged plate-like electrodes (B), the polymer compound is excellent on the surface of the structure (C). A non-woven fabric having a uniform shape and properties is obtained while being deposited while maintaining order. Moreover, the obtained nonwoven fabric can be continuously transported by continuously moving the band-shaped structure (C) serving as a polymer compound deposition portion. By setting the charging method of the deposited portion of the nonwoven fabric as described above, it is possible to reduce the extra charged portions of the equipment and to enable stable mass production of the nonwoven fabric.

The present invention is described in detail below.
The polymer compound that is the raw material of the product is uniformly dissolved in a solvent in which the polymer compound is soluble to prepare a solution containing the polymer compound. The preparation is performed in a closed stirring tank, and the inside of the tank is heated for the purpose of promoting uniform dissolution.

  Examples of the polymer compound 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, and polyvinylidene fluoride. , Polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, polyvinylidene chloride-acrylate copolymer, polyacrylonitrile, polyacrylonitrile-methacrylate copolymer, polycarbonate, polyarylate, polyester carbonate, nylon, aramid, polycaprolactone , Polylactic acid, polyglycolic acid, collagen, polyhydroxybutyric acid, polyvinyl acetate, polypeptide etc. One, and the like, but not particularly limited thereto.

  Examples of the solvent used in the present invention include methanol, ethanol, 1-propanol, 2-propanol, tetraethylene glycol, triethylene glycol, methyl isobutyl ketone, methyl-n-hexyl ketone, methyl-n-propyl ketone, Diisopropyl ketone, diisobutyl ketone, acetone, phenol, methyl formate, ethyl formate, propyl formate, methyl benzoate, ethyl benzoate, propyl benzoate, methyl acetate, ethyl acetate, propyl acetate, dimethyl phthalate, diethyl phthalate, phthalic acid Dipropyl, methyl chloride, ethyl chloride, methylene chloride, o-chlorotoluene, p-chlorotoluene, chloroform, carbon tetrachloride, 1,1-dichloroethane, 1,2-dichloroethane, dichloropropane, dibromoethane, dibro Examples include at least one of propane, methyl bromide, ethyl bromide, propyl bromide, benzene, toluene, hexane, cyclohexane, cyclopentane, o-xylene, p-xylene, m-xylene, water, and the like. It is not limited to.

  The solution containing the polymer compound uniformly dissolved in the closed stirring tank is fed from the stirring tank to the spinning section (A) via a pump. As the pump, a single-stage / multi-stage centrifugal pump, a mixed flow pump, a rotary pump, or the like can be used, and among them, a rotary pump is preferable. The spinning amount can be controlled by the number of revolutions of the pump.

  The spinning part (A) is composed of a cylinder provided with a nozzle or the like at the tip, and the solution containing the polymer compound pushed out by the pump described above passes through the nozzle toward the deposition part where the nonwoven fabric is deposited. It is spun into a shape.

  As the nozzle shape, a suitable shape can be selected from general-purpose spray nozzles, needles, spinning caps, and the like, but needles are preferred.

  In addition, the cylinder described above may be a single cylinder type or a multi-cylinder type, but in order to mass-produce planar nonwoven fabrics, many are used. In the case of the multi-cylinder type, a plurality of single-cylinder cylinders each having a nozzle or the like at the tip are arranged at regular intervals. The solution containing the polymer compound fed from the pump is equally divided into a plurality of cylinders, and is spun into fibers through a nozzle provided at the tip of each cylinder toward the deposition part where the nonwoven fabric is deposited. .

  As described above, it is preferable that the cylinder of the spinning part (A) is a multi-cylinder type, but more preferably, the cylinder is a single-cylinder type, and a plurality of holes are arranged at regular intervals at the tip thereof. This is a method of providing a spin block. The spin block is a hanger-shaped T-die having a spinning surface with a plurality of holes arranged at regular intervals at the tip.

  The solution containing the polymer compound is fed to a single cylinder cylinder, supplied to the spin block at the tip, and from the spinning surface in which a plurality of holes are arranged at regular intervals, toward the deposition part where the nonwoven fabric is deposited. And spun into fibers. According to this method, it is possible to uniformly spin a plurality of fibrous polymer compounds.

  In the charge induction spinning method, the nozzle or spin block which is the end of the spinning part (A) is charged positively or negatively. By charging the nozzle and the spin block, the solution containing the polymer compound is positively or negatively charged. Since the spun fibrous polymer compound is charged to only one of positive and negative, repulsive force between charges is generated inside the fiber, and the fiber diameter is reduced.

  The fibrous polymer compound is spun toward the electrode (B) charged to a polarity different from the charged polarity of the nozzle or spin block at the end of the spinning portion (A). Superfine fibers are deposited on the electrode to form a nonwoven fabric.

  However, as described above, in the above-described method using the electrode itself as the deposition part, not only the electrode but also the roll and the structure supporting the same are under a high voltage, and the stability and safety of production are significantly deteriorated. To do.

  Therefore, in the present invention, a plurality of holes having the same shape are provided at regular intervals between the spinning portion (A) charged positively or negatively and the plate-like electrode (B) charged to the opposite polarity to the portion. The arranged structure (C) is inserted, and a polymer compound is deposited on the surface of the structure (C).

  Moreover, the said structure (C) is made into strip | belt shape for the purpose of depositing and conveying the obtained fiber structure uniformly, and also makes the said strip | belt-shaped accumulation part into the belt conveyor form which can be transferred endlessly. The said strip | belt-shaped accumulation part is rotated with a roll, and the obtained nonwoven fabric is conveyed continuously.

  The structure (C) is preferably a structure that does not significantly disturb the electric field when a uniform charge distribution is taken into consideration. Accordingly, a mesh structure such as a wire mesh, a punched wire mesh, a perforated plate, or the like, which has been subjected to various weaving methods such as plain weave, twill weave, and plain tatami weave, is optimal.

  Furthermore, from the viewpoint of volatilization and drying of the solvent from the polymer solution as a raw material, it is desired to have air permeability, and thus a network structure such as a wire mesh or a punched perforated plate is optimal.

  However, when the mesh structure has an extremely large mesh opening, the fibrous polymer compound spun from the spinning portion (A) reaches the electrode, and therefore the nonwoven fabric is formed on the mesh structure. When it cannot be deposited and the aperture is extremely small, the uniform charge distribution is remarkably inhibited, so that a high-quality nonwoven fabric cannot be obtained. Therefore, the preferable range of the mesh structure is 5 μm to 30 mm, more preferably 5 μm to 1 mm.

  As materials for the network structure, metals such as stainless steel, aluminum and iron, alloys of these metals, various chemically synthesized resins, etc. can be taught, but considering long-term stability, solvent resistance, strength, etc. Stainless steel is used.

  By using the method described above, a nonwoven fabric having a uniform shape and characteristics can be obtained continuously. By reducing the number of extra charged parts in the non-woven fabric deposit, the manufacturing stability and safety can be improved, and the equipment cost can be reduced.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.
[Example 1]
A polylactic acid chip (5.0 g) and methylene chloride (45.0 g) were placed in a stainless steel stirring tank (internal volume: 100 mL) equipped with an anchor type stirring blade and sealed. For heating, the stirring tank was immersed in a hot water tank controlled at 25 ° C., and stirring was started at a rotational speed of 100 rpm. After 1 hour, the stirring tank was opened, and it was confirmed that polylactic acid was uniformly dissolved in methylene chloride. A stainless steel pipe was connected to the gate valve provided at the bottom of the stirring tank, and the other end point was connected to a gear pump. On the spinning side of the gear pump, a stainless steel pipe of the same type as that on the suction side was connected, and the other end of the stainless steel pipe was connected to a single cylinder cylinder made of stainless steel having an internal volume of 10 mL and a diameter of 10 mm. A spin block was connected to the bottom of the cylinder. The spinning surface of the spin block is a rectangle with a width of 100 mm and a length of 20 mm, and a plurality of holes with a hole diameter of 50 μm are provided. A plate electrode was set at a position 300 mm below the spinning surface. Between the spinning surface and the electrode, a stainless steel plain woven wire mesh with a mesh opening of 170 μm is placed at a position 150 mm below the spinning surface, and two rolls are installed to enable continuous conveyance of the deposited nonwoven fabric. did. These two rolls rotate in the same direction and have a structure capable of speed control. The spinning part (A) was the positive electrode, the electrode placed below the spinning part (A) was the negative electrode, and a high voltage of 10 kV was applied between the two. At the same time, the gate valve at the lower part of the stirring tank was opened, and the gear pump was started to be driven. Further, the polylactic acid-methylene chloride solution deposited on the nonwoven fabric was fed to the cylinder via the gear pump, and ultrafine fibers began to be spun from the spinning section (A). At this time, the temperature of the spinning part (A) was 25 ° C., the humidity was 34%, and the spinning amount was 0.9 mL / min. The nonwoven fabric was deposited on the stainless steel plain woven wire mesh, and the desired nonwoven fabric could be recovered at a conveyance speed of 1.1 m / min. When the SEM observation of the nonwoven fabric was performed, the fiber diameter of the fibers constituting the nonwoven fabric was 0.53 ± 0.07 μm.

[Example 2]
Example 1 except that the mesh size of the stainless steel plain woven wire mesh used as the non-woven fabric accumulation part is 510 μm, the temperature of the spinning part (A) is 24 ° C., the humidity is 32%, and the spinning amount is 1.2 mL / min. It carried out like. Similar to Example 1, a nonwoven fabric was deposited on the stainless steel plain woven wire mesh, and the target nonwoven fabric could be recovered by conveyance by rotation of a roll. When the SEM observation of the nonwoven fabric was performed, the fiber diameter of the fibers constituting the nonwoven fabric was 0.69 ± 0.07 μm.

[Example 3]
This was carried out in the same manner as in Example 1 except that the mesh size of the stainless steel plain woven wire mesh used as the non-woven fabric accumulation portion was 1.02 mm and the humidity of the spinning portion (A) was 38%. Similar to Example 1, a nonwoven fabric was deposited on the stainless steel plain woven wire mesh, and the target nonwoven fabric could be recovered by conveyance by rotation of a roll. As a result of SEM observation of the nonwoven fabric, the fiber diameter of the fibers constituting the nonwoven fabric was 0.81 ± 0.06 μm.

[Example 4]
The same process as in Example 3 was performed except that the polymer compound was polycarbonate chip 5.0 g, the temperature of the spinning part (A) was 22 ° C., and the humidity was 35%. Similar to Example 1, a nonwoven fabric was deposited on the stainless steel plain woven wire mesh, and the target nonwoven fabric could be recovered by conveyance by rotation of a roll. When the SEM observation of the nonwoven fabric was performed, the fiber diameter of the fibers constituting the nonwoven fabric was 0.88 ± 0.05 μm.

It is a conceptual diagram of this invention.

Explanation of symbols

1. Spinning department (A)
2. Electrode (B)
3. Structure (C)
4). High voltage generator

Claims (8)

(1) From a spinning part (A) for spinning a solution containing a positively or negatively charged polymer compound, (2) a plate-like electrode (B) charged to a polarity opposite to that of the part (3) A method for producing a nonwoven fabric in which a fiber structure made of the polymer compound is deposited,
(4) A planar structure (C) having a plurality of holes is inserted between the spinning portion (A) and the electrode (B),
(5) A method for producing a nonwoven fabric by charge dielectric spinning, wherein a nonwoven fabric is obtained by depositing a fiber structure composed of a polymer compound on the surface of the structure (C).   The accumulation part of the fiber structure formed from the structure (C) has a belt-like shape, and the nonwoven fabric obtained is continuously conveyed by continuously moving the belt-like deposition part. Item 10. A method for producing a nonwoven fabric according to Item 1.   The method according to claim 1 or 2, characterized in that the structure (C) is a network structure.   The method according to claim 3, wherein the mesh structure has an opening of 5 μm to 30 mm. A manufacturing apparatus for manufacturing a nonwoven fabric of a polymer compound by a charge dielectric spinning method,
(1) a spinning section (A) for spinning a solution containing a polymer compound positively or negatively charged;
(2) having a plate-like electrode (B) that can be charged to a polarity opposite to that of the portion;
(3) A planar structure (C) having a plurality of holes for depositing a fiber structure made of the polymer compound is inserted between the spinning part (A) and the electrode (B). A featured manufacturing device.   The structure (C) is a belt-like structure, and the structure (C) is a structure that can move continuously and transport a deposit of a fiber structure made of the polymer compound. Item 6. The manufacturing apparatus according to Item 5.   The manufacturing apparatus according to claim 6, wherein the structure (C) is a network structure.   The manufacturing apparatus according to claim 7, wherein the mesh structure has an opening of 5 μm to 30 mm.

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