JP6012932B2 - Separator manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a separator.

  Conventionally, a nanofiber composite having a structure in which a base material layer and a nanofiber layer are laminated, and a separator made of the nanofiber composite are known (for example, see Patent Document 1). Such a nanofiber composite and separator include a method for producing a nanofiber composite including an electrospinning step of forming a nanofiber layer on a base material layer by an electrospinning method (also referred to as an electrospinning method) using a polymer solution. Can be manufactured.

  According to the conventional nanofiber composite manufacturing method, it is possible to manufacture nanofiber composites having various properties by manufacturing using a base material layer and a nanofiber layer having different properties. .

  Moreover, according to the conventional nanofiber composite, it is possible to have various properties by adding the properties (wide surface area, fine voids, etc.) of the nanofiber layer to the properties of the base material layer. It becomes possible.

  Also, according to the conventional separator, compared with a separator having a general fiber layer, it has a nanofiber layer with a fine fiber average diameter and fine voids, so it has high electrolyte absorption, low ion resistance and high dendrite. It is possible to provide a separator having resistance and a thin total thickness.

The “base material layer” refers to a layer that becomes a base material for forming the nanofiber layer.
The “nanofiber” refers to a fiber made of a polymer material and having an average diameter of several nm to several thousand nm. Furthermore, the “separator” refers to a separator used for a battery (including a primary battery and a secondary battery), a capacitor (also referred to as a capacitor), and the like.

JP 2010-103050 A

  However, the conventional nanofiber composite manufactured by the conventional nanofiber composite manufacturing method has a problem that the bonding strength between the base material layer and the nanofiber layer may be small (that is, easy to peel off). . For this reason, in the conventional nanofiber composite manufacturing method, a base material layer and a nanofiber layer are obtained by using an adhesive material such as a heat-bonding fiber or a binder fiber, or an adhesive treatment such as a heat treatment, a pressure treatment, or a chemical treatment. Are bonded (for example, see paragraph [0040] of Patent Document 1). However, according to the research of the inventors of the present invention, in the above cases, the problem of the quality being deteriorated by filling the gap between the nanofibers by bonding, the process for bonding (heating treatment) Process, pressure treatment process, chemical treatment process, etc.) has been found to cause a problem of reduced productivity.

  Therefore, the present invention has been made to solve the above-described problems, and has a higher bonding strength between the base material layer and the nanofiber layer compared to the conventional nanofiber composite, and the base material layer and the nanofiber layer. To provide a nanofiber composite that can be made to have high quality and high productivity without the need for adhesion to a fiber layer, and a nanofiber composite manufacturing method that can manufacture the nanofiber composite Objective. Furthermore, it aims at providing the separator which has an above-mentioned nanofiber composite_body | complex and can be made to have high quality and high productivity.

  By the way, when nanofibers are formed on the base material layer by electrospinning, depending on the electrospinning conditions (mainly when the polymer concentration of the polymer solution is low), nanofibers and bead-like structures (substantially spherical structures) ) May be obtained in a mixed state.

Conventionally, the existence of the nanofiber layer has been known in the technical field of nanofibers, but in many cases, it has been regarded as a product of failure in setting the electrospinning conditions.
However, as a result of diligent research, the inventors of the present invention, as shown in a test example to be described later, have electrospun under an electrospinning condition in which a nanofiber layer in which nanofibers and bead-like structures are mixed is formed. When the nanofiber composite having a structure in which the base material layer and the nanofiber layer in the state are laminated is manufactured, the bonding strength between the base material layer and the nanofiber layer is increased. The invention has been completed. The present invention includes the following elements.

[1] The nanofiber composite production method of the present invention has a structure in which a nanofiber layer is formed on a base material layer by electrospinning using a polymer solution, and the base material layer and the nanofiber layer are laminated. A method for producing a nanofiber composite comprising an electrospinning process for producing a nanofiber composite having the electric field under electrospinning conditions in which a nanofiber layer in a state where nanofibers and bead-like structures are mixed is formed. A spinning process is performed.

  For this reason, according to the nanofiber composite of the present invention, similar to the conventional nanofiber composite manufacturing method, various properties can be obtained by manufacturing using a base material layer and a nanofiber layer having different properties. It becomes possible to produce a nanofiber composite having

  Further, according to the nanofiber composite of the present invention, the electrospinning process is performed under the electrospinning conditions in which the nanofiber layer in a state where the nanofibers and the bead-like structures are mixed is formed. As shown, the following nanofiber composite can be produced. That is, the bonding strength between the base material layer and the nanofiber layer is larger than that of the conventional nanofiber composite, and there is no need for adhesion between the base material layer and the nanofiber layer, resulting in high quality and high productivity. It becomes possible to produce a nanofiber composite that can be included.

[2] In the method for producing a nanofiber composite of the present invention, when the electrospinning step is performed under predetermined electrospinning conditions, the nanofiber and the bead-like structure are substantially composed of only the nanofiber. The polymer concentration at which the nanofiber layer is formed is defined as the first polymer concentration, and the polymer concentration at which a layer consisting of only the bead-like structure is formed among the nanofibers and the bead-like structure is defined as the second polymer concentration. The electrospinning step is performed under the predetermined electrospinning conditions using a polymer solution containing a polymer having a third polymer concentration lower than the first polymer concentration and higher than the second polymer concentration. Thus, it is preferable that a nanofiber layer in a state where nanofibers and bead-like structures are mixed is formed on the substrate as the nanofiber layer.

  By setting it as such a method, it becomes possible to manufacture the nanofiber composite of this invention stably.

  The “predetermined electrospinning conditions” include electrospinning conditions other than the polymer concentration of the polymer solution.

[3] In the nanofiber composite manufacturing method of the present invention, the base material layer is a base material layer having a structure in which two or more layers are laminated, and at least of the upper surface or the lower surface of the base material layer. It is preferable to perform the electrospinning process so that one surface and the side surface are covered with the nanofiber layer.

  By adopting such a method, two or more layers of the base material layer can be secured by the side surfaces by the nanofiber layer, and as a result, the bonding strength between the two or more layers can be increased. It is possible to produce a nanofiber composite that can be used.

[4] The nanofiber composite of the present invention includes a base material layer and a nanofiber layer in a state where nanofibers and bead-like structures are mixed, and the base material layer and the nanofiber layer are laminated. It has a structure.

  According to the nanofiber composite of the present invention, similar to the conventional nanofiber composite, various properties can be obtained by adding the properties (wide surface area, fine voids, etc.) of the nanofiber layer to the properties of the base material layer. It becomes possible to have such properties.

  In addition, according to the nanofiber composite of the present invention, since the nanofiber layer includes a nanofiber layer in which nanofibers and bead-like structures are mixed, the base material layer and the nanofiber are compared with the conventional nanofiber composite. The bonding strength between the layers is high, and there is no need for adhesion between the base material layer and the nanofiber layer, and it becomes possible to have high quality and high productivity.

  The nanofiber composite of the present invention includes separators for batteries (primary batteries and secondary batteries), separators for capacitors (also referred to as capacitors), industrial materials such as wiping cloths, filters, bag filters, carriers for various catalysts, Various electronic / mechanical materials, apparel such as high-function / high-sensitivity textiles, regenerative medical materials, biomedical materials, medical MEMS materials, medical materials such as biosensor materials, beauty-related products such as health care and skin care, and a wide range of other applications Can be used.

[5] In the nanofiber composite of the present invention, the average diameter of the nanofiber is in the range of 30 nm to 3000 nm, the average diameter of the bead-shaped structure is in the range of 60 nm to 5000 nm, The average diameter of the bead-like structure is preferably in the range of 2 to 100 times the average diameter of the nanofiber.

  By setting it as such a structure, it becomes possible to make the joint strength between a base material layer and a nanofiber layer still larger, and to have higher quality and higher productivity.

In the present invention, the average diameter of the nanofibers is in the range of 30 nm to 3000 nm because the production may be difficult if the average diameter is smaller than 30 nm, and the average diameter is 3000 nm. This is because if it is larger, the properties of the nanofiber may be impaired.
In the present invention, the average diameter of the bead-like structure is in the range of 60 nm to 5000 nm because the bonding strength between the base material layer and the nanofiber layer is sufficiently large when the average diameter is smaller than 60 nm. This is because it may be difficult to make the nanofiber composite thin when the average diameter is larger than 5000 nm.
Furthermore, in the present invention, the average diameter of the bead-like structure is in the range of 2 to 100 times the average diameter of the nanofibers when the average diameter is smaller than twice the average diameter of the nanofibers. This is because the bonding strength between the base material layer and the nanofiber layer may not be sufficiently increased. When the average diameter is larger than 100 times the average diameter of the nanofiber, the nanofiber composite is thinned. This may be difficult.

[6] In the nanofiber composite of the present invention, the base material layer is a base material layer having a structure in which two or more layers are laminated, and at least one of the upper surface and the lower surface of the base material layer. It is preferable that the surface and the side surface are covered with the nanofiber layer.

  By adopting such a configuration, it is possible to obtain a nanofiber composite having a high bonding strength between two or more layers, in which two or more layers of the base material layer are secured by the side surfaces by the nanofiber layer. It becomes.

[7] The separator of the present invention is characterized in that the nanofiber composite of the present invention is provided as at least one of the layers constituting the separator.

  According to the separator of the present invention, as in the case of the conventional separator, since the average fiber diameter and voids are provided with a nanofiber layer that is fine compared to a separator having a general fiber layer, the electrolyte absorbability is high and low. It has ion resistance and high dendrite resistance, and can be a separator having a thin total thickness.

  Moreover, according to the separator of this invention, since it has the nanofiber composite_body | complex of this invention, it becomes possible to have high quality and high productivity.

  The separator of the present invention can be particularly suitably used for batteries (including primary batteries and secondary batteries) and capacitors.

[8] In the separator of the present invention, the thickness of the separator is preferably in the range of 1 μm to 100 μm.

With such a configuration, it is possible to obtain a separator having sufficient mechanical strength and sufficiently low ion resistance.
In the present invention, the thickness of the separator is set in the range of 1 μm to 100 μm because the mechanical strength of the separator may not be sufficiently increased when the thickness is less than 1 μm. This is because if the thickness is greater than 100 μm, the ion resistance may not be sufficiently lowered.
From the above viewpoint, the thickness of the separator is more preferably in the range of 10 μm to 40 μm.

It is a figure for demonstrating the separator (nanofiber composite_body | complex 300) which concerns on Embodiment 1. FIG. It is a figure for demonstrating the nanofiber composite manufacturing apparatus 1 in Embodiment 1. FIG. 2 is a flowchart of a method for producing a nanofiber composite according to Embodiment 1. 2 is an electron micrograph of a nanofiber composite 300a according to Example 1. 4 is an electron micrograph of a nanofiber composite 300c according to Example 2. 6 is an enlarged cross-sectional view of a nanofiber composite 302 according to Embodiment 2. FIG.

  Hereinafter, the nanofiber composite manufacturing method, nanofiber composite, and separator of the present invention will be described based on the embodiments shown in the drawings.

[Embodiment 1]
1. Configuration of Separator (Nanofiber Composite 300) According to Embodiment 1 First, the configuration of the separator according to Embodiment 1 will be described.
FIG. 1 is a diagram for explaining a separator (nanofiber composite 300) according to the first embodiment. FIG. 1A is a perspective view of a separator wound around a core material (not shown), FIG. 1B is an enlarged cross-sectional view of the separator, and FIG. It is a schematic diagram which further expands and shows the range shown by A of (b).

  The separator according to the first embodiment includes the nanofiber composite 300 according to the first embodiment. That is, in Embodiment 1, the nanofiber composite 300 and the separator are the same. As shown in FIG. 1, the nanofiber composite 300 includes a base material layer W and a nanofiber layer 310 in which nanofibers 312 and bead-like structures 314 are mixed (see FIG. 1C). ), And the base material layer W and the nanofiber layer 310 are laminated. The thickness of the separator 300 is in the range of 1 μm to 100 μm, for example, 50 μm.

  The average diameter of the nanofiber 312 is in the range of 30 nm to 3000 nm, for example, 200 nm. The average diameter of the bead-like structure 314 is in the range of 60 nm to 5000 nm, for example, 4000 nm. Furthermore, the average diameter of the bead-like structure 314 is in the range of 2 to 100 times the average diameter of the nanofibers 312, for example, 20 times.

  The base material layer W takes the form of a long sheet, and as the base material layer W, there can be used a breathable material such as a nonwoven fabric, a woven fabric, a knitted fabric, and paper made of various materials. In the first embodiment, a fibrous base material layer is used as the base material layer W. In FIG. 1C, reference numeral 200 denotes a fiber in the base material layer W. The thickness of the base material layer W can be, for example, 1 μm to 90 μm. The length of the base material layer W can be, for example, 10 m to 10 km. In addition, as the base material layer W, things other than a fiber (for example, a porous film) can also be used.

  The separator according to Embodiment 1 is obtained by the nanofiber composite manufacturing method according to Embodiment 1 using the nanofiber composite manufacturing apparatus 1 described later.

2. Configuration of Nanofiber Composite Production Device 1 in Embodiment 1 Next, the configuration of the nanofiber composite production device 1 in Embodiment 1 will be described.
FIG. 2 is a diagram for explaining the nanofiber composite production apparatus 1 according to the first embodiment. FIG. 2A is a front view of the nanofiber composite manufacturing apparatus 1, and FIG. 2B is a view of the nozzle unit 110 viewed from the collector 150 side. In addition, in FIG.2 (b), the component (Upward nozzle 120 grade | etc.,) Arrange | positioned under the base material layer W is also illustrated. In FIG. 2, some members are shown as sectional views.

The nanofiber composite manufacturing apparatus 1 is an apparatus for manufacturing the nanofiber composite 300 according to the first embodiment. That is, it can be said that the apparatus is for manufacturing the separator according to the first embodiment.
As shown in FIG. 2, the nanofiber composite manufacturing apparatus 1 includes a transport device 10 and an electrospinning device 20. The nanofiber composite manufacturing apparatus 1 includes one electrospinning apparatus 20 as an electrospinning apparatus.

The transport apparatus 10 transports the base material layer W at a predetermined transport speed. The conveying device 10 includes a feeding roller 11 that feeds out the base material layer W, a winding roller 12 that winds up the base material layer W, tension rollers 13 and 18 that adjust the tension of the base material layer W, a feeding roller 11 and a winding roller. And an auxiliary roller 14 positioned between the two. The feeding roller 11 and the take-up roller 12 are configured to be rotated by a drive motor (not shown).
The electrospinning apparatus 20 forms the nanofiber layer 310 in a state where the nanofibers 312 and the bead-like structures 314 are mixed in the base material layer W transported by the transport apparatus 10.

  As shown in FIG. 2, the electrospinning apparatus 20 includes a housing 100, a nozzle unit 110, a polymer solution supply unit 130 (not shown), a collector 150, a power supply device 160, an auxiliary belt device 170, and the like. Is provided. The first electrospinning apparatus 20 discharges the polymer solution from the discharge ports of a plurality of upward nozzles 120 to be described later, thereby forming the nanofiber layer 310.

The housing 100 is made of a conductor.
The nozzle unit 110 has a plurality of upward nozzles 120.
Nozzle units having various sizes and shapes can be used in the separator manufacturing apparatus of the present invention, but the nozzle unit 110 has a rectangular shape (a square having a side of 0.5 m to 3 m when viewed from above. It has a block-like shape with a visible size.

  The upward nozzle 120 is a nozzle that discharges “a polymer solution that is a raw material of the nanofiber 312” supplied from a polymer solution supply unit 130 (not shown) from a discharge port. The upward nozzle 120 discharges the polymer solution upward from the discharge port. As the material constituting the upward nozzle 120, a conductor can be used, and for example, copper, stainless steel, aluminum, or the like can be used.

  The upward nozzles 120 are arranged at a pitch of 1.5 cm to 6.0 cm, for example. The number of upward nozzles 120 can be, for example, 36 (6 × 6 when arranged in the same vertical and horizontal directions) to 21904 (148 × 148 when arranged in the same vertical and horizontal directions).

  In the first embodiment, the upward nozzle 120 is used as the nozzle, but the present invention is not limited to this. A horizontal nozzle may be used as the nozzle, or a downward nozzle may be used.

The collector 150 is disposed above the nozzle unit 110. The collector 150 is made of a conductor and is attached to the housing 100 via an insulating member 152 as shown in FIG.
The power supply device 160 applies a high voltage between the upward nozzle 120 and the collector 150. The positive electrode of the power supply device 160 is connected to the collector 150, and the negative electrode of the power supply device 160 is connected to the nozzle unit 110 via the housing 100.

  The auxiliary belt device 170 includes an auxiliary belt 172 that rotates in synchronization with the conveyance speed of the long sheet W, and five auxiliary belt rollers 174 that assist the rotation of the auxiliary belt 172. Of the five auxiliary belt rollers 174, one or more auxiliary belt rollers are drive rollers, and the remaining auxiliary belt rollers are driven rollers. Since the auxiliary belt 172 is disposed between the collector 150 and the base material layer W, the base material layer W is smoothly conveyed without being attracted to the collector 150 to which a positive high voltage is applied. become.

3. Description of Nanofiber Composite Manufacturing Method According to Embodiment 1 Next, a nanofiber composite manufacturing method according to Embodiment 1 will be described.
FIG. 3 is a flowchart of the nanofiber composite manufacturing method according to the first embodiment.

  The nanofiber composite manufacturing method according to Embodiment 1 includes a polymer solution preparation step S1 and an electrospinning step S2, as shown in FIG. The nanofiber composite manufacturing method according to the first embodiment is a method for manufacturing the nanofiber composite 300 according to the first embodiment, that is, the separator according to the first embodiment, using the nanofiber composite manufacturing apparatus 1 described above. is there.

S1. Polymer Solution Production Step The polymer solution production step S1 is a step of producing a polymer solution containing a polymer material. More specifically, when the electrospinning step S2 is performed under predetermined electrospinning conditions, the polymer concentration at which a nanofiber layer composed of only the nanofibers 312 out of the nanofibers 312 and the bead-like structures 314 is formed is set to the first concentration. When the polymer concentration at which a layer consisting essentially of only the bead-like structures 314 is formed among the nanofibers 312 and the bead-like structures 314 is the second polymer concentration, it is lower than the first polymer concentration. And a step of preparing a polymer solution containing a polymer material having a third polymer concentration higher than the second polymer concentration.

  The third polymer concentration can be appropriately determined depending on the type and molecular weight of the polymer material, the type and ratio of the solvent, temperature, voltage, use of the nanofiber composite to be manufactured, and the like. As an example, when the polymer material is polyurethane, it can be set in the range of 5 wt% to 13 wt% under average electrospinning conditions.

S2. Electrospinning process The electrospinning process S2 is a nanofiber having a structure in which a nanofiber layer 310 is formed on a base material layer W by an electrospinning method using a polymer solution, and the base material layer W and the nanofiber layer 310 are laminated. This is a step of manufacturing the composite 300, which is performed under predetermined electrospinning conditions in which the nanofiber layer 310 in a state where the nanofibers 312 and the bead-like structures 314 are mixed is formed.

First, the produced polymer solution is supplied to the nozzle unit 110 through the polymer solution supply path 130.
Next, the base material layer W, which is a long sheet, is set on the transport device 10, and then the base material layer W is transported from the feed roller 11 toward the take-up roller 12 at a predetermined transport speed V, and each electric field is applied. In the spinning device 20, the nanofiber layer 310 is formed on the base material layer W, and the nanofiber composite 300 according to the first embodiment, that is, the separator is manufactured. The separator is wound around the winding roller 12.

  Below, the spinning conditions in Embodiment 1 are shown as an example.

  Examples of the polymer material for producing the polymer solution include polylactic acid (PLA), polypropylene (PP), polyvinyl acetate (PVAc), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN). ), Polyamide (PA), polyurethane (PUR), polyvinyl alcohol (PVA), polyacrylonitrile (PAN), polyetherimide (PEI), polycaprolactone (PCL), polylactic acid glycolic acid (PLGA), silk, cellulose, chitosan Etc. can be used.

  As a solvent for producing the polymer solution, for example, dichloromethane, dimethylformamide, dimethyl sulfoxide, methyl ethyl ketone, chloroform, acetone, water, formic acid, acetic acid, cyclohexane, THF and the like can be used. A plurality of types of solvents may be mixed and used. The polymer solution may contain an additive such as a conductivity improver.

  The first transport speed and the second transport speed can be set to, for example, 0.2 m / min to 100 m / min. The voltage applied to the nozzle, collector 150 and nozzle unit 110 can be set to 10 kV to 80 kV, and is preferably set to around 50 kV.

  The temperature of the spinning zone can be set at 25 ° C., for example. The humidity of the spinning area can be set to 30%, for example.

  Hereinafter, effects of the nanofiber composite manufacturing method, the nanofiber composite, and the separator 300 according to the embodiment will be described.

  According to the nanofiber composite manufacturing method according to the first embodiment, as in the conventional nanofiber composite manufacturing method, by using the base material layer and the nanofiber layer having different properties, there are various types. It becomes possible to produce a nanofiber composite having properties.

  Moreover, according to the nanofiber composite manufacturing method according to the first embodiment, the electrospinning process is performed under the electrospinning condition in which the nanofiber layer in a state where the nanofibers and the bead-like structures are mixed is formed. It becomes possible to manufacture the nanofiber composite 300 according to Form 1.

  In addition, according to the nanofiber composite manufacturing method according to Embodiment 1, a predetermined electrospinning is performed using a polymer solution containing a polymer having a third polymer concentration lower than the first polymer concentration and higher than the second polymer concentration. Since the electrospinning process is performed under conditions, the nanofiber composite 300 according to Embodiment 1 can be stably manufactured.

  According to the nanofiber composite 300 according to the first embodiment, as in the conventional nanofiber composite, the properties (wide surface area, fine voids, etc.) of the nanofiber layer are added to the properties of the base material layer. Thus, it becomes possible to have various properties.

  Moreover, according to the nanofiber composite 300 according to the first embodiment, the nanofiber composite 310 includes the nanofiber layer 310 in a state where the nanofibers 312 and the bead-like structures 314 are mixed, so that it is compared with the conventional nanofiber composite. The bonding strength between the base material layer and the nanofiber layer is high, and there is no need for adhesion between the base material layer and the nanofiber layer, and it is possible to have high quality and high productivity.

  In addition, according to the nanofiber composite 300 according to the first embodiment, the average diameter of the nanofibers 312 is in the range of 30 nm to 3000 nm, and the average diameter of the bead-like structures 314 is in the range of 60 nm to 5000 nm. In addition, since the average diameter of the bead-like structure 314 is in the range of 2 to 100 times the average diameter of the nanofiber 312, the bonding strength between the base material layer and the nanofiber layer is further increased. It becomes possible to have high quality and higher productivity.

  According to the separator according to Embodiment 1, as in the case of the conventional separator, the average fiber diameter and voids are provided with a nanofiber layer that is fine compared to a separator having a general fiber layer, so that the electrolyte absorbability is high. It has low ion resistance and high dendrite resistance, and can be a separator having a thin total thickness.

  Moreover, according to the separator which concerns on Embodiment 1, since the nanofiber composite_body | complex 300 which concerns on Embodiment 1 is provided, it becomes possible to make it have high quality and high productivity.

  Moreover, according to the separator which concerns on Embodiment 1, since the thickness of a separator exists in the range of 1 micrometer-100 micrometers, it is set as the separator which has sufficient mechanical strength and sufficiently low ion resistance. Is possible.

[Example 1]
FIG. 4 is an electron micrograph of the nanofiber composite 300a according to Example 1.
In Example 1, the nanofiber composite 300a defined by the present invention was actually manufactured, and the structure of the nanofiber composite 300a was confirmed.

The manufacturing method of the nanofiber composite 300a according to Example 1 is as follows.
First, a polymer solution used for the electrospinning process was prepared. The polymer solution was prepared using polyvinylidene fluoride (PVDF; purchased from Sigma-Aldrich) as a raw material and a mixed solvent of dimethylacetamide (DMAc): methyl ethyl ketone (MEK) = 7: 3. The raw materials and the solvent were stirred at room temperature for 3 hours, and dissolution of the raw materials was confirmed. The polymer concentration was adjusted to 19 wt%.

  Next, a nanofiber composite having a structure in which a nanofiber layer is formed on a base material layer by an electrospinning method using the polymer solution prepared as described above, and the base material layer and the nanofiber layer are laminated. The electrospinning process for producing

As the base material layer, general Japanese paper (main component is cellulose, average fiber diameter is about 20 μm) was used.
The electrospinning conditions were a nozzle-collector distance (TCD) of 10 cm and an applied voltage of 6 kV.

As shown in FIG. 4, it was confirmed that the nanofiber composite 300a manufactured as described above formed a nanofiber layer in a state where nanofibers and bead-like structures were mixed. In addition, the thick fiber reflected in the background in FIG. 4 is a fiber which comprises Japanese paper.
In the nanofiber composite 300a, the average diameter of the nanofiber is approximately 80 nm, the average diameter of the bead-shaped structure is approximately 2000 nm, and the average diameter of the bead-shaped structure is approximately 25 times the average diameter of the nanofiber. there were.

Thus, the structure of the nanofiber composite 300a defined by the present invention could be confirmed.
Also, when the bonding strength between the base material layer and the nanofiber layer was confirmed by rubbing the nanofiber layer side of the nanofiber composite 300a with a finger, it was confirmed that the nanofiber layer did not peel off due to the high bonding strength. did it.

[Comparative example]
In the comparative example, when the nanofiber layer is formed on the base material layer, the nanofiber composite is obtained by performing the electrospinning process under an electrospinning condition in which a nanofiber layer substantially consisting of only nanofibers is formed. The body 300b was actually manufactured, and the bonding strength between the base material layer and the nanofiber layer was confirmed.

  The manufacturing method of the nanofiber composite 300b according to the modified example was the same as the manufacturing method of the nanofiber composite 300a according to Example 1 except that the polymer concentration was adjusted to 24 wt%. Omitted.

  When the nanofiber layer side of the nanofiber composite 300b manufactured as described above was rubbed with a finger to confirm the bonding strength between the base material layer and the nanofiber layer, the nanofiber composite 300a according to Example 1 was confirmed. Unlike the case, it was confirmed that the nanofiber layer was peeled off because the bonding strength between the base material layer and the nanofiber layer was small.

[Example 2]
FIG. 5 is an electron micrograph of the nanofiber composite 300c according to Example 2.
In Example 2, the nanofiber composite 300c defined by the present invention was actually manufactured, and the structure of the nanofiber composite 300c was confirmed.

  The manufacturing method of the nanofiber composite 300c according to Example 2 is the same as that of the nanofiber composite 300a according to Example 1 except that a PE film separator (Celgard single-layer polyethylene separator, manufactured by Celgard) was used as the base layer. Since the method is the same as the manufacturing method, details are omitted.

Also in the nanofiber composite 300c manufactured as described above, as shown in FIG. 5, the nanofibers in a state where the nanofibers and the bead-like structures are mixed as in the nanofiber composite 300a according to Example 1. It was confirmed that a layer was formed.
Also in the nanofiber composite 300c, the average diameter of the nanofiber is about 80 nm, the average diameter of the bead-like structure is about 2000 nm, and the average diameter of the bead-like structure is about 25 times the average diameter of the nanofiber. there were.

Thus, the structure of the nanofiber composite 300c defined by the present invention could be confirmed.
Further, when the bonding strength between the base material layer and the nanofiber layer was confirmed by rubbing the nanofiber layer side of the nanofiber composite 300c with a finger, the bonding was performed similarly to the nanofiber composite 300a according to Example 1. It was confirmed that the nanofiber layer did not peel off due to the high strength.

[Embodiment 2]
FIG. 6 is an enlarged cross-sectional view of the nanofiber composite 302 according to the second embodiment.
The nanofiber composite 302 according to the second embodiment has basically the same configuration as the nanofiber composite 300 according to the first embodiment, but the configuration of the base material layer and the nanofiber layer is the nanostructure according to the first embodiment. This is different from the case of the fiber composite 300. That is, in the nanofiber composite 302 according to Embodiment 2, as shown in FIG. 6, the base material layer is a base material layer having a structure in which two layers W1 and W2 are laminated. The upper surface and the side surface are covered with the nanofiber layer 320.

  The nanofiber composite manufacturing method for manufacturing the nanofiber composite 302 according to the second embodiment is basically the same as the nanofiber composite manufacturing method according to the first embodiment. The point which performs an electrospinning process so that a side surface is covered with the nanofiber layer 320 differs from the nanofiber composite manufacturing method which concerns on Embodiment 1. FIG. As a nanofiber composite manufacturing method according to the second embodiment, for example, the nozzle interval is increased so that the nanofiber layer 320 can be formed up to the side surface of the substrate layer, or the width of the substrate layer is decreased. Can be considered.

  As described above, in the nanofiber composite manufacturing method according to the second embodiment, at least one of the upper surface and the lower surface of the base material layer and the side surface are in a state where nanofibers and bead-like structures are mixed. Although the point of performing the electrospinning process so as to be covered with the fiber layer 320 is different from the case of the nanofiber composite manufacturing method according to the first embodiment, the nanofiber composite manufacturing method according to the first embodiment is similar to the nanofiber composite manufacturing method. Since the electrospinning process is performed under the electrospinning conditions in which the nanofiber layer in which the fibers and the bead-like structures are mixed is formed, the nanofiber composite of the present invention can be manufactured.

  In addition, according to the nanofiber composite manufacturing method according to the second embodiment, the nanofiber layer 320 enables the two layers of the base material layer to be locked at the side surface, and as a result, between the two layers. It becomes possible to produce a nanofiber composite that can also increase the bonding strength of.

  In the nanofiber composite manufacturing method according to Embodiment 2, the electrospinning process is performed so that at least one of the upper surface and the lower surface of the base material layer is covered with the nanofiber layer. Since the method is basically the same as the nanofiber composite manufacturing method according to the first embodiment, the corresponding effect among the effects of the nanofiber composite manufacturing method according to the first embodiment is directly provided.

  The nanofiber composite 302 according to Embodiment 2 is different from the nanofiber composite 300 according to Embodiment 1 in the configuration of the base material layer and the nanofiber layer, but the nanofiber composite 300 according to Embodiment 1 Similarly, since the nanofiber layer 320 in a state where nanofibers and bead-like structures are mixed is provided, the bonding strength between the base material layer and the nanofiber layer is larger than that of the conventional nanofiber composite. In addition, it is not necessary to bond the base material layer and the nanofiber layer, and it becomes possible to have high quality and high productivity.

  In addition, according to the nanofiber composite 302 according to the second embodiment, the nanofiber layer 320 has two layers of the base material layer secured at the side surface, and the nanofiber composite having high bonding strength between the two layers. The body can be made.

  The nanofiber composite 302 according to the second embodiment has basically the same configuration as the nanofiber composite 300 according to the first embodiment except for the configuration of the base material layer and the nanofiber layer. Of the effects of the nanofiber composite 300 according to the first embodiment, the corresponding effects are provided as they are.

  As mentioned above, although this invention was demonstrated based on said embodiment, this invention is not limited to said embodiment. The present invention can be implemented in various forms without departing from the spirit thereof, and for example, the following modifications are possible.

(1) The number, positional relationship, and size of each component in each of the above embodiments are examples, and the present invention is not limited to this.

(2) In Embodiment 1 described above, the separator of the present invention has been described using the separator made of the nanofiber composite 300 as an example, but the present invention is not limited to this. For example, the separator may further include a layer (reinforcing member or the like) other than the nanofiber composite.

(3) In Embodiment 1 described above, the nanofiber composite 300 of the present invention has been described using a separator as an example, but the present invention is not limited to this. The nanofiber composite of the present invention includes industrial materials such as wiping cloths, filters, bag filters, various catalyst carriers, various electronic / mechanical materials, clothing such as high-functional and high-sensitive textiles, regenerative medical materials, and biomedical materials. It can be used for medical MEMS materials, medical materials such as biosensor materials, beauty-related products such as health care and skin care, and various other applications.

(4) The nanofiber composite 300 according to Embodiment 1 is manufactured using the nanofiber composite manufacturing apparatus 1 described above, but the present invention is not limited to this. The nanofiber composite of the present invention can be manufactured using various nanofiber composite manufacturing apparatuses.

(5) Although the nanofiber composite according to each of the above embodiments is manufactured by the nanofiber composite manufacturing method according to each of the embodiments, the present invention is not limited to this. The nanofiber composite of the present invention can be produced using various nanofiber composite production methods.

(6) Although the nanofiber composite manufacturing method according to Embodiment 1 is performed using the nanofiber composite manufacturing apparatus 1, the present invention is not limited to this. The nanofiber composite production method of the present invention can be performed using various nanofiber composite production apparatuses.

(7) In the second embodiment, the nanofiber composite of the present invention has been described by taking the nanofiber composite 302 having two base layers and one nanofiber layer 320 as an example. It is not limited to this. The present invention can also be applied to a nanofiber composite having three or more base layers or two or more nanofiber layers.

(8) In the nanofiber composite manufacturing apparatus used in the present invention, a nozzle unit other than the block-like nozzle unit, for example, a tubular nozzle unit may be used.

(9) In the first embodiment, the present invention has been described by taking the nanofiber composite manufacturing apparatus 1 including one electrospinning apparatus 20 as an electrospinning apparatus, but the present invention is not limited to this. Absent. For example, a nanofiber composite manufacturing apparatus including two or more electrospinning apparatuses can be applied to the present invention.

DESCRIPTION OF SYMBOLS 1 ... Separator manufacturing apparatus, 10 ... Conveying device, 11 ... Feeding roller, 12 ... Winding roller, 13, 18 ... Tension roller, 14 ... Auxiliary roller, 20 ... Electrospinning device, 100 ... Housing, 110 ... Nozzle unit, DESCRIPTION OF SYMBOLS 120 ... 1st nozzle, 150 ... Collector, 152 ... Insulator, 160 ... Power supply device, 170 ... Auxiliary belt device, 172 ... Auxiliary belt, 174 ... Roller for auxiliary belt, 200 ... Fiber of base material layer, 300, 302 ... Nanofiber composite, 310, 320 ... nanofiber layer, 312 ... nanofiber, 314 ... bead-like structure, W ... substrate layer

Claims (5)

As at least one layer among the layers constituting the separator,
A base material layer;
Formed on the base material layer by electrospinning using a polymer solution, comprising a nanofiber layer in a state where nanofibers and bead-like structures are mixed,
A separator manufacturing method for manufacturing a separator comprising a nanofiber composite having a structure in which the base material layer and the nanofiber layer are laminated,
Manufacturing method of the separator, characterized by forming the nanofiber layer by nano fiber and bead-like structure and to practice the electrospinning process by electrospinning conditions nanofiber layer is formed of a mixed state. In the manufacturing method of the separator of Claim 1,
When the electrospinning step is carried out under predetermined electrospinning conditions, a polymer concentration at which a nanofiber layer consisting essentially of only the nanofibers among the nanofibers and the bead-like structures is formed is defined as a first polymer concentration. When the polymer concentration at which a layer consisting essentially of only the bead-like structure is formed among the nanofibers and the bead-like structure is the second polymer concentration,
Before Symbol lower than the first polymer concentration, the nano by performing the electrospinning process at the predetermined electrospinning conditions using higher than said second polymer concentration polymer solution containing a polymer of a third polymer concentration separator aerator manufacturing method, which comprises forming a fiber layer. In the manufacturing method of the separator of Claim 1 or 2,
The average diameter of the nanofiber is in the range of 30 nm to 3000 nm,
The average diameter of the bead-like structure is in the range of 60 nm to 5000 nm,
The average diameter of the beaded structure, manufacturing method of the separator, characterized in that in the range of 2 times to 100 times the average diameter of the nanofibers. In the manufacturing method of the separator in any one of Claims 1-3,
The base material layer is a base material layer having a structure in which two or more layers are laminated,
And one surface of the upper surface or lower surface of at least the base layer, the manufacturing method of the separator, wherein a and the side to form the nanofiber layer so that covered by the nanofiber layer. In the manufacturing method of the separator in any one of Claims 1-4,
The thickness of the separator, a manufacturing method of the separator, characterized in that in the range of 1 m to 100 m.