JP2013091869A - Method of producing nanofiber laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of mass-producing nanofiber laminate in which a nonwoven fabric or a film with low or no air permeability can be used as a substrate.SOLUTION: A method of producing nanofiber laminate comprising the steps of applying strong electric field to generate nanofiber and spraying the nanofiber onto a collecting part. The collecting part comprises a plane part with nearly a plane serving as a net-like collection belt made of synthetic resin which allows air to pass through endlessly. At a rear side of the collection belt disposed is a suction mechanism by which nanofiber is attached to the collection belt to form a nanofiber laminate. The nanofiber laminate thus obtained is transported from the plane part to a take-off part. The take-off part comprises an electrification part for charging electrostatic which attracts the charged nanofiber laminate and an air blowing part for blowing air for taking nanofiber laminate off, thereby taking nanofiber laminate off and transporting the nanofiber laminate to a desirable substrate.

Description

  The present invention relates to a method for producing a laminate using nanofibers, and more particularly to a method for producing a nanofiber laminate capable of forming a laminate by being self-supported only by nanofibers.

Recently, nanofibers, which are generally defined as fibers having a diameter of 1 micron (= 1,000 nm) or less, have been developed. As a method for producing nanofibers, an ESD (Electro-Spray Deposition) method, Alternatively, a technique called electrospinning method has received the most attention, and the technique has been developed (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).
In the production of nanofibers by this ESD method, first, a syringe is filled with a solution of various biopolymers or polymers (hereinafter sometimes simply referred to as “polymers”) dissolved or melted in a solvent. A strong electric field is applied between the needle electrode and the collector electrode by applying a DC high voltage of several kV to several tens of kV from the high voltage DC power source between the needle electrode and the collector electrode on which the nanofibers are deposited. Generate a field.
In this environment, when the spinning solution is discharged from the needle-type electrode toward the collector electrode, the solvent that dissolved the polymer evaporates instantaneously in the electric field, and the polymer stretches with Coulomb force while solidifying. Then, nano-order fibers are formed under mild conditions at room temperature and atmospheric pressure.

Nanofibers can be expected to exhibit unique functions due to nanostructures. For example, nanofibers have a surface area in the same volume that is much larger than that of normal fibers. In addition, new functions such as adsorption properties and adhesive properties are developed, and development of new materials that are not possible in the past can be expected. Research on multifunctional special protective clothing worn by police officers, firefighters, doctors, and nurses has begun, and military applications are military uniforms that are lighter than before and have functions that have never existed, gathering in nanometer units. Development of new laminated materials with different functions is progressing. Furthermore, as shown in Patent Document 4, since the filter made of nanofibers can increase the space for a small area occupied by the fibers, it can be expected to have high collection efficiency with low pressure loss. Air filters, masks, etc. have been developed, and ultra-lightweight, high-functional protective clothing for biochemical hazard protection using nanofibers and regenerative medicine using nanofibers as a medium are being actively developed.
In addition, it is transparent to visible light, the pore size can be controlled in the nano order, advanced molecular organization is possible, and the living body does not feel nanofiber as a foreign substance and has good biocompatibility. It is done.

The manufacturing method or apparatus of nanofibers by the ESD method has a drawback that it is not suitable for mass production because the spray amount from one nozzle is very small. In the ESD method, although it varies depending on the compound and spray conditions, the spray speed from one nozzle is usually about several μρ per minute. Therefore, when mass production is performed, a large number of nozzles are arranged, A method of electrostatic spraying from a nozzle is employed. The manufacturing method of the ESD nanofiber using such a large number of nozzles requires a large number of nozzles, so that the quality is insufficient, maintenance is difficult, and the manufacturing cost is high. It was. Therefore, as disclosed in Patent Document 5 and Patent Document 6, the amount of spinning (discharge) from one nozzle is greatly increased, and the nanofiber filter is made of a nanofiber filter with a simple manufacturing method at a time. We have developed and provided a method for producing nanofiber laminates that have sufficient strength by spraying to take advantage of their properties.
In these nanofiber laminate manufacturing methods, nanofibers are collected by spraying on a plate or drum by spraying and static electricity. There were difficulties.
Therefore, as shown in Patent Document 7, the present applicant makes the collection surface of the nanofiber laminate a flat plate, and uses a breathable base material as a moving belt from the back side of the collection side of the nanofiber laminate. It provides a method for producing a large amount of nanofiber laminate by sucking efficiently by suction.

JP2002-249966 JP 2004-68161 A JP 2008-274487 A JP 2006-289209 A JP2010-121221A JP2011-127234A Japanese Patent Application No. 2011-90534

As mentioned above, in the production of nanofiber laminates, the structure that sucks air from the back side of the collection surface has enabled the nanofiber laminates to be collected dramatically more efficiently. There must be a strong base material,
In addition, there is a problem that the base material must be breathable so that a large amount of air can be ventilated, and a small air-permeable material such as a normal nonwoven fabric or film cannot be used.
The present invention has been made in view of the above-mentioned problems, and intends to provide a manufacturing method for manufacturing a large amount of nanofiber laminates that can use a non-permeable or non-breathable nonwoven fabric or film as a base material. In addition, the present invention intends to provide a method for efficiently producing a nanofiber laminate.

In order to solve the above-mentioned problem, the invention of claim 1 is a manufacturing method in which a strong electric field is generated to produce nanofibers and sprayed onto the collecting parts to laminate the nanofibers. A flat part is formed, and a collecting band is formed on the flat part as a net-like shape through which endlessly moving air made of synthetic resin passes, and a suction mechanism for sucking air is provided on the back side of the collecting band. The nanofibers are sucked onto the collection zone to form a nanofiber laminate, and the formed nanofiber laminate is transferred from the planar portion to the separation portion, and the separation portion attracts the charged nanofiber laminate. It consists of a charger that charges static electricity and a blower that blows air so as to separate from the collection zone, and the nanofiber laminate is separated from the collection zone and detached. The nanofiber laminate is a manufacturing method of the nanofiber laminated body characterized by transferring the desired substrate.
According to a second aspect of the present invention, in the method for producing a nanofiber laminate according to the first aspect, a static eliminator is provided immediately downstream of the separation portion.

  According to the method for producing a nanofiber laminate of the present invention, since the nanofiber laminate has a low occupation ratio of the nanofiber itself, it is thick and has less air passage resistance. The nanofiber laminate can be efficiently formed by the suction mechanism that sucks air, and the nanofiber laminate is created by utilizing the charged state of the nanofiber laminate produced by generating a strong electric field. A charger and a blower that charge static electricity that attracts the body are provided, and it can be easily removed from the collection zone and transferred to a desired base material. That is, a small non-permeable nonwoven fabric or a non-breathable film can be used as a substrate. Thus, mass production of the nanofiber laminated band is possible at low cost.

Conceptual schematic diagram of mainly nanofiber generation part on the upstream side of the method for producing a nanofiber laminate of an embodiment of the present invention, FIG. 1 is a conceptual schematic diagram of mainly the collection part, separation part, base material attachment part, temporary fixing part, product winding part of the nanofiber laminate, Explanatory drawing which shows the electric lines of force of the metal ball of the present invention and the spinning nozzle, 4 (a) is an explanatory view showing the relationship between the metal sphere, the high-speed air current injection nozzle, and the spinning nozzle in FIG. 1, FIG. 4 (b) is an explanatory view from the side of FIG. 4 (a), An explanatory view of a single nanofiber manufacturing apparatus in which a plurality of metal spheres and the spinning nozzle units are arranged in a nanofiber generation unit, Side view from line 8-8 in FIG. FIG. 3 is an enlarged view of a separation part in FIG. 2.

A feature of the present invention is that, in the electrospinning method for producing a nanofiber by generating a strong electric field, suction is used as a method for collecting the nanofiber laminate, and at the same time, only the nanofiber laminate is collected. It is characterized in that a desired base material is transferred by being detached from the substrate, and a nanofiber laminate having a charged state is used as the separation, and a release plate having an opposite charge is provided and nano The fiber laminate can be easily and easily transferred to a desired substrate.
Below, the suitable Example of the manufacturing method of the nanofiber laminated body of this invention is described with reference to drawings.

  Although the manufacturing method of the nanofiber laminated body N of Example 1 of this invention is demonstrated, as shown in the conceptual explanatory drawing which showed the outline of FIG. 1 and FIG. 2, FIG. 1 and FIG. 2 are continuous apparatuses, Fig. 1 mainly shows a nanofiber generation section upstream, which basically employs a jet ESD method combining ESD (Electro-Spray Deposition) and a high-speed jet stream (jet). FIG. 2 is a collection part K of the nanofiber laminate N downstream thereof, and FIG. 2 is a separation part of the nanofiber laminate N downstream of FIG. Part L, base material attachment part P for attaching a base material such as a film to the surface of the nanofiber laminate N, temporary fixing part (spot welding) Q for temporarily fixing the attached base material, and product winding part R It is configured.

[Nanofiber generation part J]
First, the nanofiber generation part J in FIG. 1 on the upstream side will be described. Examples of the polymer material having a long molecular arrangement of the present invention include biopolymer solutions such as proteins, organic polymer solutions, polymer solutions, and the like, but the nanofiber production apparatus (production method) of Example 1 is highly expensive. Polyethersulfone (PES) is used as the molecular material. The reason why this polyethersulfone (PES) is used is that, in addition to excellent heat resistance, it is possible to produce thinner nanofibers of 100 nm to 50 nm with the production apparatus disclosed in the present invention.
The material supply unit 1 in FIG. 1 contains a polymer solution N1 obtained by dissolving polyether sulfone (PES) as a material with DMF (dimethylformamide) as an organic solvent.
The polymer solution N1 in the material supply unit 1 is subjected to extrusion pressure by the gear pump 11. The polymer solution N1 is supplied by the gear pump 11 capable of accurately delivering a predetermined amount through the supply pipe 12 so as to push out the predetermined amount to the spinning nozzle 21. The polymer solution N1 is introduced into the metal spinning nozzle portion 2 through the supply pipe 12, and is spun into the spinning nozzle portion 2 from the opening 211 at the tip of the spinning nozzle 21. Here, by appropriately adjusting the above-described gear pump 11 that adjusts the speed at which the polymer solution N1 is spun, appropriate discharge is performed so that nanofibers are uniformly generated from the plurality of spinning nozzles 21 as described later. Adjust to speed.

By the way, the principle of the ESD method is that a polymer material having a long molecular arrangement such as polyethersulfone (PES) is swollen with a flammable organic solvent and exists in a disperse state. When released, the solvent rapidly evaporates due to the large surface area, shrinks laterally, and aligns in the longitudinal direction of the polymer molecular chain. Then, the polymer elongates due to the evaporation of the solvent and the accompanying increase in the Coulomb force. By repeating this, it gradually grows and grows into nanofibers. It is considered that the polymers that were disjointed as the polymers stretched are aligned while being intertwined. In the case where the material is a low molecule, the length of the molecule itself is short, so that the nano particles are generated without being entangled.
Therefore, by adjusting the discharge speed of the polymer solution N1, it is possible to obtain a dry deposit instead of a wet deposit formed at an excessive speed. That is, it is necessary to adjust the discharge speed to a limit that does not cause wet deposits.

In FIG. 1, a metal part metal ball 31 that forms a spherical electrode part 3 is disposed in the generation unit device frame M so as to face the opening direction of the spinning nozzle 21 and the opening 211 of the spinning nozzle. 211 and the shortest surface distance of the metal sphere 31 are installed at a predetermined interval.
The spinning nozzle 21 is also made of a conductive metal, and a high voltage power source 33 is applied to the spinning nozzle 21 and the metal ball 31, and a negative voltage of the high voltage power source 33 is applied to the metal ball 31. It is supplied via a lead wire, and the plus side is grounded G via the lead wire.
By applying a high voltage from the high voltage power source 33, a positive voltage is applied to the polymer solution N1 via the spinning nozzle 21, and the polymer in the polymer solution N1 to be spun is charged positively. The Note that the plus and minus are not limited to those in the first embodiment, and it is sufficient that a charge is applied to the polymer material. Conversely, the polarity of the voltage applied to the polymer solution N1 may be minus. .
In addition, the metal guide tube 22 up to the spinning nozzle 21 of the spinning nozzle unit 2 is heated by a heater 23 such as a heater to reduce the viscosity of the polyethersulfone (PES) as much as possible. Is heated to about 80 ° C.

The reason why the negative electrode is the metal sphere 31 is that, as shown in FIG. 3, the electric lines of force E are concentrated at the maximum at the opening 211 at the tip of the spinning nozzle 21, and the charged polymer solution The polymer material N1 inside jumps out linearly toward the metal sphere 31. Therefore, the diameter of the metal sphere 31 may be set such that the electric field lines E are most efficiently concentrated on the spinning nozzle 21. In the prior art, the diameter of the sphere is assumed to be 25 mm assuming that a charged state is generated. The high voltage was 30 Kv, but the distance between the spinning nozzle 21 and the metal sphere 31 was 55 mm to 65 mm so as not to discharge, although the optimum value varied depending on the voltage of the high voltage power source. By the way, if the diameter of the metal sphere is too small and it is made to be a needle, a discharge occurs and short-circuits, and the spinning nozzle 21 and the metal sphere 31 are not charged.
Further, the high-speed airflow injection nozzle portion 4 positioned between the spinning nozzle 21 and the metal ball 31 needs to be made of a synthetic resin made of an insulating material instead of metal so as not to be charged.

Here, the charged nanofibers are electrostatically induced in the course of floating from the spinning nozzle 21, and the amount of charge (+) in the opening 211 of the spinning nozzle 21 is neutralized. If it is sufficient, it will float as a droplet. However, the path of the nanofiber to be spun is changed by a jet nozzle 41 (see FIG. 1) of a high-speed airflow, which will be described later. By removing from the gap, both can still keep the capacitor coupling and the production can be increased, which is also an important feature of the present invention.
In this embodiment, the metal ball 31 and the spinning nozzle 21 are applied by the high voltage power source 33 and the spinning nozzle 21 is set to the ground G. Therefore, the spinning nozzle 21 (ground G) is applied by applying the metal ball 31. ) Is electrostatically induced, and the charge is supplied to the polymer of the nanofiber. Basically, the metal sphere 31 is merely electrostatically induced, and the current is supplied from the ground side to consume power. Is zero. This is also one of the important features of the present invention, and even if the number of spinning nozzles 21 is sufficiently increased and arranged in parallel, a small high-voltage power supply is sufficient. Therefore, the production units Y of the metal spheres 31 and the high-speed air jet nozzles 41 can be reduced in size, and the production units Y per unit area can be concentrated to greatly increase the production amount.

Next, a high-speed air flow injection nozzle portion 4 that discharges a high-speed air flow is arranged in the path between the metal ball 31 and the spinning nozzle opening 211 so as to be orthogonal to each other. The high-speed airflow X generated by the high-pressure pump 42 from the injection nozzle 41 of the high-speed airflow injection nozzle section 4 generates a low pressure at the spinning nozzle opening 211 and generates a force for sucking up the polymer solution N1 from the opening 211. . Therefore, the high-speed airflow X needs to be on a line (path) connecting the metal ball 31 and the spinning nozzle opening 211.
Therefore, in this embodiment, as shown in FIG. 4B, a plurality of openings 411 (three in FIG. 1) of the jet nozzle 41 for high-speed airflow are provided horizontally, and the airflow layer has a predetermined width in the horizontal direction. Therefore, the high-speed airflow X can be easily located on the line (path) connecting the metal ball 31 and the spinning nozzle opening 211.

The high-speed airflow X is air dried to a humidity of 30% or less by a dryer in this embodiment, and the temperature is kept constant so that the state of the nanofiber is kept constant, and the wind speed is 200 m / By setting the aspect ratio of the nanofiber to a large value for sec or more, the evaporation of the solvent is promoted, and as a result, the polymer material is cured, but it is maximized until it cannot be stretched by Coulomb force until it is cured. It will be.
Therefore, the distance from the nozzle opening 211 to the collection surface of the nanofiber collection part L1 also needs to be a distance for the nanofiber to extend to the nano unit. In Example 1, it depends on the temperature in the apparatus. However, the distance is about 1 m or more. Actually, this distance is set to 4 m or more to make the stacking state uniform on the collecting surface. By increasing the distance, air is sucked from the back surface of the base material, and the suction force is increased at a rough spot. Therefore, the nanofibers are attracted to the portion to be laminated uniformly.
In addition, one of the important features of the present invention is that the charge is generated at a low pressure generated in the vicinity of the opening 211 by the Coulomb force from the metal sphere 31 and the opening 411 of the high-speed airflow injection nozzle portion 4 and the injection nozzle 41. It is to give a high-speed air flow of 200 m / sec or more that is dried at a constant temperature necessary for the production of nanofibers by linearly ejecting the polymer.

Here, the arrangement of the openings 411 of the jet nozzle 41 for high-speed airflow will be described with reference to FIG.
A distance C (C in FIG. 4) from the line B connecting the spinning nozzle 21 and the metal sphere 31 to the opening 411 of the injection nozzle 41 is 3 mm to a right angle from the line regardless of the diameter of the metal sphere 31. The production of nanofibers is preferred at position C about 4 mm apart. It should be noted that the speed of the air sprayed from the opening 411 of the spray nozzle 41 is rapidly decelerated even at a position of 3 mm, so that even if the speed is significantly increased to 200 m / sec or more, the effect is weak.
Next, the distance D from the injection nozzle opening 411 of the high-speed air current injection nozzle section 4 is 8.5 mm to 10 mm in the horizontal distance (distance D) from the linear spinning nozzle opening 211 regardless of the diameter of the metal ball 31. Production of nanofibers is preferred. Further, the opening 411 of the high-speed airflow injection nozzle has a horizontal distance (distance D) from the spinning nozzle opening 211 of 8.5 mm to 10 mm, and the opening 411 defines the bottom surface 311 of the metal ball 31 and the spinning nozzle opening 211. A position that is parallel to the connecting line B and is 3 mm to 4 mm away from the spinning nozzle opening 211 by a vertical distance (distance C) is preferable.

Further, when the diameter of the metal sphere 31 is reduced, the distance B (FIG. 3) between the bottom surface 311 of the metal sphere 31 and the spinning nozzle opening 211 can be reduced, and the voltage of the high voltage is also reduced. If the diameter is made too small and close to a needle shape, (1) the vicinity will not be charged, but a short circuit will occur due to discharge, and the charged atmosphere as shown in FIG. (2) It becomes droplets or liquid particles, and nanofibers are not generated in this case. Therefore, by setting the diameter of the metal ball 31 from 8 mm to 4 mm, the distance between the metal ball 31 and the spinning nozzle opening 211 can be changed from 11.5 mm to 22 mm, and the high voltage can be set from 3 kv to 13 kv. The nanofiber can be produced by one nanofiber produced from one spinning nozzle 21 regardless of the amount produced, but when the nanofiber is transported by high-speed air. Is accumulated in a non-woven fabric on the collection surface by a random traverse action.
Here, in order to produce a large amount of nanofibers, as shown in FIG. 5, a plurality of the spinning nozzles 21 shown in FIG. You can collect in.

[Conditions of Jet ESD Method of Example 1]
In Example 1 shown in FIG. 1, it can be seen from Table 3 that the diameter of the metal sphere is 5 mm under the condition that the nanofibers can be stably and satisfactorily formed. Therefore, the diameter A is 5 mm and the distance B is 16 mm. The voltage was set to -13 kv.
Setting conditions Material: Polyethersulfone (PES)
Solvent: DMF (dimethylformamide)
Fiber generator voltage: -13kv
High-speed air pressure: 0.4 MPa
Spinning amount (discharge amount): 0.5 mL / min
Diameter of metal sphere: 5mm
Distance between spinning nozzle and metal ball: 16mm
Distance from nozzle opening to collection surface: 3m
Absorption negative pressure at the collecting surface: 200Pa

In the experimental apparatus under the setting conditions in the above examples, nanofibers having a diameter of 50 nm to 100 nm can be produced. This is because the lower thin fibers in the electron micrographs shown in FIGS. Sulphone (PES) nanofiber.
Although only one nanofiber is spun from the spinning nozzle 21 in FIG. 1, the polyethersulfone (PES) nanofibers are in a non-woven fabric (web) form due to random traverse action or the like. You can see the state of lamination.
Note that substantially the same results were obtained with polyetherimide (PEI), polyurethane (PU), and polyvinylidene fluoride (PVDF) instead of polyethersulfone (PES) as the material in Example 1.

In this example, DMF (dimethylformamide) was used as the solvent for polyethersulfone (PES), but similar results can be obtained with other dimethylacetamide (DMAc).
Other polymer and solvent combinations include polyvinyl alcohol (PVA) and water, polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), and polyether sulfone (Polysulfone). Ether Sulphone, PES) and dimethylacetamide (DMAc) or DMF (dimethylformamide), nylon (Nylon) and formic acid, chitosan and acetic acid or citric acid and other weak acids, acrylic (polymethyl methacrylate, PMMA) and methanol, polylactic acid and chloroform Combinations and the like are possible for the production of nanofibers.

[Nanofiber Laminate N Collection Part K (5)]
Next, the collection part K (5) of the nanofiber laminate N in which the nanofibers produced in the nanofiber production part J are laminated downstream will be described with reference to FIG.
As shown in FIG. 2, the collection part 5 of the nanofiber laminate N is a net-like collection band 51 that moves endlessly. The material is a non-conductive synthetic resin, and the shape is a net or net. Any material that can pass a large amount of air may be used. In this embodiment, a polypropylene (PP) monofilament net having a diameter of 0.4 to 0.6 mm is used as the synthetic resin, and a density of 15 to 20 pieces / inch is used. Therefore, the air resistance of the penetrating air is sufficiently small.
The collecting band 51 moves counterclockwise by the driving roller 52, is supported at a predetermined position by the driven support rollers 53a to 53f, and passes through a predetermined portion. In FIG. 2, a substantially flat collecting surface 54 is formed by driven support rollers 53e and 53f at positions facing the nanofiber generating portion J, and the nanofiber laminate N is continuously collected by the collecting surface 54. Then, the nanofiber laminate N is peeled off by moving to a later-described detachment portion L and turned upward by the drive 52, and further guided to the hot water tank 55 by the driven support roller 53a to be paired in the hot water tank 55. Are guided by the following driven support rollers 53b, c, and are guided and circulated by the original driven support rollers 53e.

On the back side of the collection surface 54, there are provided a suction chamber 561, a plurality of suction ducts 562a, b, c (upper, middle and lower in this embodiment) in the vertical direction and an air suction mechanism 56 connected to these. The suction ducts 562a, b, c are respectively provided with air volume adjusting shutters 563a, b, c for adjusting the air volume, and the nanofibers and the nanofiber laminate N generated by the nanofiber generating section J are provided. Sucking into the collecting zone 51.
In order to keep the collecting band 51 flat, a flat surface holding member 541 such as a synthetic resin is provided on the back surface thereof at an interval. A trumpet-shaped guide member 542 is provided on the front side of the collection surface 54 so as to converge on the collection surface 54 in order to efficiently guide the nanofibers to the collection surface 54.
The suction ducts 562a, b, c are respectively provided with air volume adjustment shutters 563a, b, c for adjusting the air volume, but the suction amount of the nanofiber laminate N on the collection surface 54 is determined by the suction. If the opening areas of the ducts 562a, b, and c are the same, the amount of nanofibers laminated decreases and the wind speed increases toward the upstream (upper side) of the collection band 51. In order to make the air velocity almost uniform, the opening area is adjusted. The opening area is smaller by the air volume adjusting shutter 563a in the upper suction duct 562a, and larger by the air volume adjusting shutter 563c in the lower suction duct 562c. The suction duct 562b is adjusted to have an intermediate opening area by the suction duct 562b.
Thus, the nanofiber laminate N formed vertically and continuously on the collection zone 51 moves and moves horizontally in the right direction as the collection zone 51 moves downward, and the nanofibers at the separation portion L. The laminated body N is detached and guided to the hot water tank 55.
The warm water tank 55 is filled with warm water, and the nanofibers remaining in the collection band 51 are peeled off by a pair of rotating brushes 551 that are rotated by a drive motor 552 while the collection band 51 passes through the warm water. The collection band 51 in a clean state is sent again to the collection surface 54.

[Separation part L of nanofiber laminate N (6)]
The above-described detachment portion L (6) has the function of transferring the formed nanofiber laminate N, peeling the transferred nanofiber laminate N from the collection zone 51, and transferring it to a desired substrate. Is.
Since the generation of nanofibers is basically based on ESD (Electro-Spray Depos), the injected nanofibers themselves usually have a positive (minus) charge. The drum was grounded and the drum itself was positively charged and collected.
On the other hand, since the collection of the present invention is an air suction method, nanofibers can be collected by using a metal net instead of a metal plate. It will not be easy. This is because, as described above, since the nanofiber has a negative (minus) charge, if a metal net is used, a grounding point is inevitably generated and the charge of the nanofiber itself is lost. Is strongly entangled in the metal net and is considered to be difficult to peel off.

Therefore, FIG. 7 is provided with a mechanism as shown in the enlarged view of the detachment portion 6 in FIG. 2, focusing on the fact that the nanofiber itself in the present invention has a charge, Focusing on the fact that the nanofiber laminate N is attracted or separated by the charging of the charger, the nanofiber laminate N is separated from the collection band 51.
As described above, the collection band 51 is made of a monofilament made of polypropylene (PP), which is an insulating resin, and collected in the collection band 51 while the nanofibers retain electric charge. L (6) is transported, and a charger 61 is provided at an appropriate position of the collecting band 51 for transporting the nanofiber laminate N. The charging edge 611 of the charger 61 has a width of the nanofiber laminate N. It extends over the entire width in the direction, and draws the nanofiber laminate N downward and separates it from the collection zone 51.
In this case, when the charger 61 is charged, in this embodiment, the charging edge 611 of the charger 61 is −18 Kv by the high voltage power supply 612 (preferably the use range is ± 15 Kv to ± 20 Kv). It was found that the laminate N and the lower film attachment F1 were sucked and the nanofiber laminate N could be peeled off from the simple collection band 51.
It should be noted that the charging of the charger 61 may vary depending on the state of charge in the upstream nanofiber generator, the polarity, the material of the collection band 51, etc. In this case, the collection band 51 and the nanofiber laminate N may be set to polarities or voltage values at which they are most efficiently separated.
Setting conditions of separation part (this example)
Speed of collection zone 51: 0.5 m / min Charger 6: −15 Kv to −20 Kv (optimal value: −18 Kv)
X1 spacing: 5-15mm (10mm)
X2 spacing: 15-25mm (20mm)
X3 spacing: 30-50mm (40mm)
Distance between charger and lower surface of lower film F1: 30 to 75 mm (50 mm)
Blower pressure: 0.1 MPa

In this embodiment, the nanofiber laminate N can be peeled off from the collection band 51 only by charging of the charger 61, but air is blown from above the collection band 51 and the nanofiber laminate N to support this. The apparatus 63 may blow peeling air downward through the mesh of the collection band 51. The wind pressure of the blower 63 in this embodiment was set to 0.1 MPa.
Further, if the static elimination 64 is provided immediately after the charger 61 so that the separated nanofiber laminate N does not adhere to the collection zone 51 again, the collection zone 51 and the nanofiber laminate N can be separated more smoothly. This is where the work is done, and the results of the experiment proved. The structure of this static elimination 64 applies AC5-7Kv with the alternating current power supply 641, and makes the electric charge on the collection belt | band | zone 51 and the nanofiber laminated body N zero.
In FIG. 7, the interval between the collection band 51 and the nanofiber laminate N is 10 mm at the position X1 of the upstream first insulating guide roller 75b. 5mm to 15mm is preferable, and the X2 position of the charging edge 621 of the charger 62 is 20mm, preferably 15mm to 25mm. The charging edge 621 and the nanofiber laminate The distance from N is set to 50 mm, but a range of 30 to 75 mm is preferable. Further, the opening is wide as 40 mm so that the peeled air can smoothly escape at the position X3 of the downstream second insulating guide roller 75c, but preferably 30 mm to 50 mm.
The height of the insulating guide rollers 75b and 75c can be adjusted by the adjusting unit, and the height of the charging edge 621 can be adjusted by the adjusting unit 62.

[Substrate attachment part P (7)]
(Lower film attached)
The detachment part 6 also serves as a part of the base material attachment part P (7). The lower film (PP film) F1, which is the lower base material, is sent out above the charger 61 to form a nanofiber laminate. N is attached.
In FIG. 2, the feeding roll 71a wound with the lower delivery film is intermittently driven so as to be fed by a drive motor 72a. The drive interval of the drive motor 72a is set between the guide rollers 74a and 74b at fixed positions. A dancer arm 73a coaxial with the drive motor 72a and a tip swing roller 731a are provided between them, and the storage state is detected by the position of the swing roller 731a. When the dancer arm 73a moves counterclockwise and the storage amount decreases, the feeding roll 71a is driven so that the film F1 is fed out. When the dancer arm 73a moves clockwise and the storage amount becomes sufficient, the supply roll The drive of 71 is stopped.
The lower film (PP film) F1 is guided from the guide roller 74b to the guide roller 74c, and is guided to the upper side of the charger 61 by the guide metal roller 75a and the insulating guide roller 75b of the separation portion 6, and is applied by the charger 61. At the same time as the nanofiber laminate N is peeled downward from the collection zone 51 by electricity, a lower film (PP film) F1 is attached, and the lower film (PP film) is attached to the lower side of the nanofiber laminate N. It is transferred from the guide insulating roller 75c to the next step with F1 attached.
An edge sensor 741 for detecting both end positions in the width direction of the lower film (PP film) F1 is provided downstream of the guide roller 74b, and a feeding unit 7a comprising a feeding roll 71a and a driving motor 72a is output by the output of the edge sensor 741. Moves in the axial direction of the feeding roll 71a to prevent meandering of the lower film (PP film) F1.

(Upper film attached)
Next, the process of sending the upper film (PP film) F2 as the upper substrate to the nanofiber laminate N with the lower film attached thereto and attaching it to the nanofiber laminate N will be described. However, it is not always necessary to attach the upper film F2 as long as it is sufficiently strong and does not get entangled during rewinding and is separated smoothly.
In FIG. 2, the upper film feed mechanism has almost the same structure, but the upper feed film feed roll 71b is intermittently driven so as to be fed by a drive motor 72b, and the drive interval of the drive motor 72b is a guide for a fixed position. A dancer arm 73b coaxial with the drive motor 72b and a tip swinging roller 731b are provided between the rollers 76a and 76b, and the storage state is detected by the position of the swinging roller 731b. When the dancer arm 73b moves counterclockwise and the storage amount decreases, the feeding roll 71b is driven so that the film F2 is fed out. When the dancer arm 73b moves clockwise and the storage amount becomes sufficient, the roll 71b is driven. The drive is stopped.
The upper film (PP film) F2 is guided by the guide rollers 76b to 76c, and the upper film (PP film) F2 is attached to the upper surface of the nanofiber laminate N by the guide rollers 76d.
An edge sensor 761 for detecting both end positions in the width direction of the upper film (PP film) F2 is provided downstream of the guide roller 76b, and the feeding unit 7b including the feeding roll 71b and the driving motor 72b is output by the output of the edge sensor 761. The upper film (PP film) F2 is prevented from meandering by moving in the axial direction of the feeding roll 71b.

(Driving process)
The nanofiber laminate N attached as the lower film F1 on the lower surface of the nanofiber laminate N and the upper film F2 on the upper surface is attracted from the guide roller 77 to the main drive roller 78 driven by the drive motor 781 for the next process. Be transported. The surface speed of the main driving roller 78 is synchronized with the surface speed of the driving roller 52 of the collecting unit 5 described above, and moves the nanofiber laminate N from the collecting band 51 to the main driving roller 78 at a constant speed. ing. In this embodiment, drive motors synchronized with each other are used.
A press roller 782 that freely rotates is provided above the main drive roller 78, and a pair of pressure regulators 783 that can adjust the pressure below the press roller 782 are provided in the vicinity of the left and right ends of the press roller 782. On the other hand, an edge sensor 784 is provided upstream of the main drive roller 78, and the output of the edge sensor 784 is input to the pressure regulator 783, and the nanofiber on the side of the press roller 782 pressurized by the pressure regulator 783. Since the laminated body N is slightly delayed by the resistance, the entire meandering of the nanofiber cleaning belt laminated body is corrected.

[Temporary fixing part of nanofiber laminate N (spot welding) Q (8)]
The nanofiber laminate N to which the upper and lower attached films F1 and F2 are attached will be peeled off or displaced immediately by this alone, so the nanofiber laminate N is temporarily fixed by spot welding. Product. This temporarily fixed nanofiber laminate N is for further pressing or adding a base material to be attached according to the demand of the customer.
The mechanism of this temporary fixing part (spot welding) Q (8) will be described with reference to FIGS.
The temporary fixing portion 8 includes a needle portion 81 that is heated by the heater 23 arranged at an interval in the width direction, a large vertical movement cylinder 82 that controls the rough vertical position, and a fine adjustment to accurately adjust the vertical position. It consists of two upper and lower cylinders of a small vertical cylinder 83 to be controlled and a needle receiving portion 84. During spot welding of the temporary fixing portion 8, the movement of the nanofiber laminate N is temporarily stopped at the lowered position of the needle portion 81. And a temporary stop mechanism 85.
The needle part 81 descends at regular intervals in the length direction, and the hot heat needle part 81 penetrates into the nanofiber laminate N. At this point, the partial films F1, F2 and the nanofiber melt and adhere to each other. For this reason, an intermittent drive roller 851 and an intermittent drive motor 852 that are intermittently controlled are provided, and when the rotation of the intermittent drive roller 851 stops, the nanofiber stack between the intermittent drive roller 851 and the guide roller 853 is provided. The movement of the body N is stopped, and the heated needle portion 81 is lowered by the small vertical movement cylinder 83 and raised by spot welding.

At this time, since a constant amount of the nanofiber laminate N is always supplied from the main drive roller 78, a storage device is provided between the main drive roller 78 and the guide roller 853 in order to absorb this. The accumulation device temporarily accumulates the loosened nanofiber laminate N when the dancer roller 854 moving up and down moves up and down.
When this spot welding is completed, the intermittent drive roller 851 and the intermittent drive motor 852 are driven again, and the accumulated nanofiber laminate N is taken up at a high speed and returned to the state of the dotted line in FIG.
A press roller 856 that freely rotates is provided above the intermittent drive roller 851, and a pair of pressure adjusters 857 that can adjust the pressure below the press roller 856 are provided near the left and right ends of the press roller 856. On the other hand, an edge sensor 858 is provided upstream of the intermittent drive roller 851, and the output of the edge sensor 858 is input to the pressure adjuster 857, and on the side of the press roller 856 pressurized by the pressure adjustment 857. The nanofiber laminate N is slightly delayed by the resistance force, so that the entire meandering of the nanofiber cleaning strip laminate is corrected.

[Product winding part R (9) of product nanofiber laminate N]
As shown in FIGS. 2 and 6, the product nanofiber laminate N sent out from the intermittent drive roller 851 of the temporary fixing portion 8 is taken up by the product take-up portion R (9). The rotary shaft 92 is taken up by a take-up drive motor 94 through a powder clutch 93. The product take-up unit 9 is provided with a take-up diameter detecting ultrasonic sensor 95, and the take-up tension changes due to a change in the take-up diameter. Therefore, the rotational speed of the motor is controlled so as to keep this tension constant, Since the powder clutch 93 is provided between the take-up drive motor 94 of the drive source and the rotary shaft 92, slippage occurs when an excessive load is applied, and the product nanofiber laminate N can be taken up with a constant tension. .

As described above, the manufacturing method of the nanofiber laminate N according to the embodiment of the present invention is a combination of the electrostatic induction ESD method and the high-speed air flow, and the metal sphere is made as small as possible. The distance B between the bottom surface 311 and the spinning nozzle opening 211 can be shortened, and the high voltage can be reduced from 13 kv to 3 kv.
In addition, according to the method for producing the nanofiber laminate N of the present invention, the nanofiber laminate N has a low occupation ratio of the nanofiber itself, so that it is thick and has low air passage resistance, so that the suction force is reduced. Therefore, the nanofiber laminate N can be efficiently formed by a suction mechanism that sucks air,
Furthermore, taking advantage of the fact that the nanofiber laminate N generated by generating a strong electric field is in a charged state, a release plate charged with static electricity that attracts the nanofiber laminate N is provided, so that it can be easily captured. It can be separated from the banding and transferred to a desired base material. The desired base material is not only a breathable base material, but also a non-breathable nonwoven fabric or film that is breathable. be able to. Thus, mass production of the nanofiber laminated band is possible at low cost.
Needless to say, the present invention is not limited to the above-described embodiments as long as the features of the present invention are not impaired. For example, although the nanofiber material is polyethersulfone (PES) in this embodiment, the material is not limited to this as long as the nanofiber can be manufactured.

J ... Nanofiber generation part, K ... Nanofiber laminate N collection part,
L ・ ・ Removal part, P ・ ・ Base attachment part, Q ・ ・ Temporary fixing part (spot welding),
R ... Product take-up part,
E ... Electric field lines, G ... Ground, F1 ... Lower film, F2 ... Upper film,
N ... Nanofiber laminate N1 ... Polymer solution (PES), N2 ... Adhesive (EVA),
N3 .. Base material (PP non-woven fabric),
X ... High-speed airflow, Y ... Generation unit,
1 .... Material supply section (material container), 11 .... Gear pump (discharge means),
12 .... Supply piping,
2 .... Spinning nozzle part, 21 ... Spinning nozzle, 211 ... Spinning nozzle opening,
22 .. Induction cylinder, 23 .. Heater (heater),
3 .. Electrode part, 31 .. Metal sphere, 311 .. Bottom surface, 33 .. High voltage power supply,
4 .... High-speed air current injection nozzle part, 41 .... Injection nozzle, 411 ... Open,
42. ・ High pressure pump,
5. Collecting part,
51..Collector, 52..Drive roller, 53a-f..Supported support roller,
54..Collecting surface, 541..Plane holding member, 542..Guide member,
55 ... Hot water tank, 551 ... Rotary brush, 552 ... Drive motor,
56..Suction mechanism, 561..Suction chamber, 562a, b, c..Suction duct,
563a, b, c .. air volume adjustment shutter 563,
6. Departing part,
61 .... Charger, 611 ... Charging edge, 612 ... High voltage power supply,
62 .... Adjustment unit, 63 .... Blower, 64..Non-charger, 65..AC power supply 7..Base material attachment, 7a, 7b..Feeding unit,
71a, b ... feed roll, 72a, b ... drive motor,
73a, b ... dancer arm, 731a, b ... swing roller,
74a, b, c .. Lower film guide roller, 741, 761 .. Edge sensor,
75a, b, c .... Insulation guide roller at the separation part,
76a, b, c, d .. Insulation guide roller for upper film,
77. ・ Guide roller
78 ..Main drive roller, 781 ..Drive motor, 782 ..Press roller,
783 ... Pressure adjuster, 784 ... Edge sensor,
8. Temporary fixing part (spot welding), 81 ... Needle part, 82 ... Large vertical cylinder,
83 .. Small vertical movement cylinder, 84.
85 .. Pause mechanism, 851 .. Intermittent drive roller, 852 .. Intermittent drive motor,
853 ... Guide roller, 854 ... Dancer roller, 856 ... Press roller,
857 ・ ・ Pressure adjuster, 858 ・ ・ Edge sensor,
9. Product take-up part, 91 ... Product take-up roll, 92 ... Rotary shaft,
93 ... Powder clutch, 94 ... Winding drive motor,
95 .. Winding diameter detection ultrasonic sensor,

Claims (2)

In the production method of generating nanofibers by generating a strong electric field and spraying the nanofibers on the collecting part to laminate the nanofibers,
The collection part forms a substantially flat plane part, and forms a collection band in the form of a net through which endlessly moving air made of synthetic resin passes on the flat part,
A suction mechanism for sucking air is provided on the back side of the collection zone to draw nanofibers onto the collection zone to form a nanofiber laminate,
The formed nanofiber laminate is transferred from the planar portion to the separation portion, and the separation portion blows air so as to separate from the charging zone and the collecting band that charge the static electricity that attracts the charged nanofiber laminate. A method for producing a nanofiber laminate, wherein the nanofiber laminate is separated from the collection zone, and the detached nanofiber laminate is transferred to a desired substrate.   The method for producing a nanofiber laminate according to claim 1, wherein a static eliminator is provided immediately downstream of the separation part.

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