JP2013155451A - Method for producing high-strength composite nanofiber assembly and high-strength composite nanofiber assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a high-strength composite nanofiber assembly capable of producing a composite nanofiber assembly having higher mechanical strength than that of a conventional composite nanofiber assembly.SOLUTION: The method for producing the high-strength composite nanofiber assembly comprises: a first step S1 of producing a composite nanofiber assembly containing a first nanofiber formed of a first polymer having a first melting point and a second nanofiber formed of a second polymer having a second melting point that is lower than the first melting point; and a second step S2 of heating the composite nanofiber assembly to a temperature lower than the first melting point and higher than the second melting point to produce the high-strength composite nanofiber assembly having a structure in which the first nanofibers are partially bonded to each other by the second polymer, in this order.

Description

  The present invention relates to a method for producing a high-strength composite nanofiber assembly and a high-strength composite nanofiber assembly.

  Conventionally, the composite nanofiber nonwoven fabric manufacturing apparatus for manufacturing the composite nanofiber nonwoven fabric containing 2 or more types of nanofibers is known (for example, refer patent document 1).

  FIG. 13 is a view for explaining a conventional composite nanofiber nonwoven fabric manufacturing apparatus 900. As shown in FIG. 13 (FIG. 1 of Patent Document), a conventional composite nanofiber nonwoven fabric manufacturing apparatus 900 is a polymer solution that stores a polymer solution of type A among different types (type A and type B). A nozzle having a tank 910, a polymer solution tank 920 that stores a type B polymer solution, a plurality of first nozzles 930 that discharge a type A polymer solution, and a plurality of second nozzles 940 that discharge a type B polymer solution A unit 950, a collector 960 that accumulates nanofibers electrospun from the nozzle unit 950, and a power supply device 970 that applies a high voltage between the nozzle unit 950 and the collector 960 are provided.

  According to the conventional composite nanofiber nonwoven fabric manufacturing apparatus 900, two types (type A and type B) of polymer solutions can be simultaneously electrospun, so that a composite nanofiber nonwoven fabric including two types of nanofibers is manufactured. It becomes possible to do. At this time, since the composite nanofiber nonwoven fabric manufactured by the conventional composite nanofiber nonwoven fabric manufacturing apparatus 900 includes two types of nanofibers each having different properties, a general nanofiber nonwoven fabric composed of a single nanofiber is included. Compared with, it has various characteristics.

Special table 2009-510272 gazette

  By the way, in the industrial world, a material having higher mechanical strength than ever has been demanded, and composite nanofiber nonwoven fabrics are no exception. Such a requirement is not a requirement that exists only in the composite nanofiber nonwoven fabric, but a requirement that exists in the entire composite nanofiber assembly including the composite nanofiber filament.

  Then, this invention is made | formed in view of the above situations, and provides the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly which can manufacture the composite nanofiber aggregate | assembly which has mechanical strength higher than before. For the purpose. Moreover, it aims at providing the high intensity | strength composite nanofiber aggregate | assembly which has mechanical strength higher than before.

  [1] The method for producing a high-strength composite nanofiber assembly of the present invention includes a first nanofiber made of a first polymer having a first melting point and a second polymer having a second melting point lower than the first melting point. A first step of producing a composite nanofiber assembly including the second nanofiber, and heating the composite nanofiber assembly to a temperature lower than the first melting point and higher than the second melting point, And a second step of producing a high-strength composite nanofiber assembly having a structure in which the first nanofibers are partially bonded to each other by the second polymer in this order.

  According to the method for producing a high-strength composite nanofiber assembly of the present invention, the first nanofiber made of the first polymer having the first melting point and the second polymer made of the second polymer having the second melting point lower than the first melting point. A first step of manufacturing a composite nanofiber assembly including two nanofibers, and a temperature lower than the first melting point and higher than the second melting point while pressurizing the composite nanofiber assembly manufactured by the first step Since the second step of producing the high-strength composite nanofiber aggregate by heating is included, the high-strength composite nanofiber aggregate manufactured by the second step is partially separated from each other by the second polymer. It becomes a high-strength composite nanofiber assembly having a structure bonded to. For this reason, the high-strength composite nanofiber assembly produced by the method for producing a high-strength composite nanofiber assembly of the present invention becomes a composite nanofiber assembly having higher mechanical strength than before.

  In addition, since the high-strength composite nanofiber assembly manufactured by the method for manufacturing a high-strength composite nanofiber assembly of the present invention has only the first nanofibers partially bonded to each other, The entire fiber assembly is not stiffened, and a high-strength composite nanofiber assembly can be obtained while maintaining the “flexibility” of the composite nanofiber assembly to some extent.

  In the present invention, the “composite nanofiber assembly including the first nanofiber and the second nanofiber” is in a state where the first nanofiber and the second nanofiber are entangled as shown in FIG. 4 described later. When the first nanofiber and the second nanofiber are included, as shown in FIG. 8 to be described later, the first nanofiber and the second nanofiber are combined with the first nanofiber and the second nanofiber laminated. The case where it contains or the case where it contains a 1st nanofiber and a 2nd nanofiber in states other than these is included.

  In the present invention, the “high-strength composite nanofiber assembly” refers to a composite nanofiber assembly that has higher strength than the composite nanofiber assembly manufactured in the first step. The same applies to “high-strength composite nanofiber nonwoven fabric” and “high-strength composite nanofiber filament” described later.

  [2] In the method for producing a high-strength composite nanofiber assembly of the present invention, in the first step, a composite nanofiber nonwoven fabric is prepared as the composite nanofiber assembly, and in the second step, the composite nanofiber assembly is prepared. It is preferable to produce a high-strength composite nanofiber nonwoven fabric as the high-strength composite nanofiber aggregate by heating the fiber nonwoven fabric while applying pressure.

  By setting it as such a method, it becomes possible to manufacture the composite nanofiber nonwoven fabric which has higher mechanical strength than before.

  [3] In the method for producing a high-strength composite nanofiber assembly of the present invention, in the first step, a first polymer solution containing the first polymer, and a second polymer solution containing the second polymer, It is preferable to produce the composite nanofiber nonwoven fabric by electrospinning each from a different nozzle.

  By setting it as such a method, the composite nanofiber nonwoven fabric which mixed the 1st nanofiber which consists of a 1st polymer, and the 2nd nanofiber which consists of a 2nd polymer can be manufactured.

  [4] In the method for producing a high-strength composite nanofiber assembly of the present invention, in the first step, a band-shaped composite nanofiber nonwoven fabric is created as the composite nanofiber assembly, and in the second step, It is preferable to produce a high-strength composite nanofiber filament as the high-strength composite nanofiber aggregate by heating the band-shaped composite nanofiber nonwoven fabric while twisting and stretching.

  By setting it as such a method, it becomes possible to manufacture the composite nanofiber filament which has higher mechanical strength than before.

  [5] In the method for producing a high-strength composite nanofiber assembly of the present invention, in the first step, a first polymer solution containing the first polymer, and a second polymer solution containing the second polymer; It is preferable that the composite nanofiber nonwoven fabric is produced by electrospinning each from a different nozzle, and then the composite nanofiber nonwoven fabric is cut to produce the strip-shaped composite nanofiber nonwoven fabric.

  By setting it as such a method, it can respond | correspond to any case with the case where a composite nanofiber nonwoven fabric is used as it is, and the case where a strip | belt-shaped composite nanofiber nonwoven fabric is used.

  [6] In the method for producing a high-strength composite nanofiber assembly of the present invention, in the first step, a first polymer solution containing the first polymer, and a second polymer solution containing the second polymer, It is preferable to produce the band-shaped composite nanofiber nonwoven fabric by electrospinning the film from different nozzles.

  By setting it as such a method, it becomes possible to manufacture a strip-shaped composite nanofiber nonwoven fabric efficiently with high productivity. Moreover, since it becomes a strip | belt-shaped composite nanofiber nonwoven fabric from the beginning, the effect that the cutting device for setting it as a strip | belt-shaped composite nanofiber nonwoven fabric becomes unnecessary is also acquired.

  [7] In the method for producing a high-strength composite nanofiber assembly of the present invention, the weight of the first nanofiber contained in the composite nanofiber assembly is M1, and the first nanofiber assembly contains the first nanofiber. It is preferable that the relationship of “0.01 ≦ M2 / (M1 + M2) ≦ 0.40” is satisfied when the weight of the two nanofibers is M2.

  The reason why it is preferable to satisfy such a relationship is that when M2 / (M1 + M2) is less than 0.01, bonding between the first nanofibers by the melted second polymer may be insufficient. Yes, if M2 / (M1 + M2) exceeds 0.40, the characteristics as the composite nanofiber aggregate may be deteriorated. From this viewpoint, it is preferable to satisfy the relationship of “0.02 ≦ M2 / (M1 + M2) ≦ 0.20”. In particular, when producing a composite nanofiber mainly composed of the first nanofiber by the first polymer, it is more preferable to satisfy the above relationship.

  [8] In the method for producing a high-strength composite nanofiber assembly of the present invention, when the average diameter of the first nanofiber is D1 and the average diameter of the second nanofiber is D2, “0.01 ≦ It is preferable to satisfy the relationship of “D2 / D1 ≦ 0.50”.

  The reason why it is preferable to satisfy such a relationship is that when D2 / D1 is less than 0.01, bonding between the first nanofibers by the melted second polymer may be insufficient. This is because if D2 / D1 exceeds 0.50, the properties of the composite nanofiber assembly may be deteriorated. From this point of view, it is preferable to satisfy the relationship of “0.02 ≦ D2 / D1 ≦ 0.20”. In particular, when producing a composite nanofiber mainly composed of the first nanofiber made of the first polymer, it is more preferable to satisfy the above-described relationship.

  [9] In the method for producing a high-strength composite nanofiber assembly of the present invention, when the first melting point is T1 and the second melting point is T2, the relationship of “T1-T2 ≧ 10 ° C.” is satisfied. Is preferred.

  This means that the first melting point T1 and the second melting point T2 preferably have a difference of 10 ° C. or more. The reason why it is preferable to satisfy this relationship is that if the difference between the first melting point T1 and the second melting point T2 is less than 10 ° C., only the second nanofibers are melted in a state where the first nanofibers remain. This is because it is difficult to set the temperature, and it is difficult to bond the first polymers with the melted second polymer.

[10] In the method for producing a high-strength composite nanofiber assembly of the present invention, the first polymer and the second polymer may be polymers of different materials.
This means, for example, that polyureta is used as the first polymer and polyvinylidene fluoride is used as the second polymer. In this case, it is preferable to satisfy various conditions necessary for carrying out the present invention, such as the melting point of the first polymer and the melting point of the second polymer.

  [11] In the method for producing a high-strength composite nanofiber assembly of the present invention, the first polymer and the second polymer may be polymers having the same material and different number average molecular weights.

  This is because even if the first polymer and the second polymer are the same material and are the same, the melting point and the like can be made different by different number average molecular weights. Can also be used. Also in this case, it is preferable that various conditions necessary for carrying out the present invention are satisfied.

  [12] The high-strength composite nanofiber assembly of the present invention includes a first nanofiber made of a first polymer having a first melting point and a second polymer made of a second polymer having a second melting point lower than the first melting point. A high-strength composite nanofiber assembly manufactured from a composite nanofiber assembly including nanofibers, wherein the first nanofibers are partially bonded to each other by the second polymer. To do.

  Since the high-strength composite nanofiber aggregate of the present invention is a high-strength composite nanofiber aggregate having high mechanical strength, industrial materials such as filters, separators for secondary batteries, separators for capacitors, various catalyst carriers, Electronic and mechanical materials such as sensor materials, regenerative medical materials, biomedical materials, medical MEMS materials, medical materials such as biosensor materials, garments such as wiping cloths, high-functional and high-sensitivity textiles, and beauty such as health care and skin care It can be used for a wide range of other related products.

It is a flowchart explaining each process of the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly of this invention. FIG. 3 is a view for explaining a method for producing a composite nanofiber assembly according to Embodiment 1. FIG. 3 is a view for explaining a method for producing a composite nanofiber assembly according to Embodiment 1. FIG. 3 is a view for explaining a method for producing a composite nanofiber assembly according to Embodiment 1. FIG. 3 is a view for explaining a method for producing a composite nanofiber assembly according to Embodiment 1. FIG. 3 is a view for explaining a method for producing a composite nanofiber assembly according to Embodiment 1. It is a figure shown in order to demonstrate the manufacturing method of the composite nanofiber aggregate | assembly which concerns on Embodiment 2. FIG. It is a figure shown in order to demonstrate the manufacturing method of the composite nanofiber aggregate | assembly which concerns on Embodiment 2. FIG. It is a figure shown in order to demonstrate the manufacturing method of the composite nanofiber aggregate | assembly which concerns on Embodiment 3. FIG. It is a figure shown in order to demonstrate the manufacturing method of the composite nanofiber aggregate | assembly which concerns on Embodiment 3. FIG. It is a figure shown in order to demonstrate the manufacturing method of the composite nanofiber aggregate | assembly which concerns on Embodiment 3. FIG. It is a figure shown in order to demonstrate the high intensity | strength composite nanofiber aggregate | assembly manufacturing method which concerns on Embodiment 4. FIG. It is a figure shown in order to demonstrate the conventional composite nanofiber nonwoven fabric manufacturing apparatus 900. FIG.

  Hereinafter, a method for producing a high-strength composite nanofiber assembly and a high-strength composite nanofiber assembly of the present invention will be described. Before describing the embodiments, first, the basic steps in the method for producing a high-strength composite nanofiber assembly in the present invention will be described.

  FIG. 1 is a flowchart for explaining each step of the method for producing a high-strength composite nanofiber assembly of the present invention. As shown in FIG. 1, the method for producing a high-strength composite nanofiber assembly in the present invention includes a first nanofiber made of a first polymer having a first melting point T1, and a second melting point T2 lower than the first melting point T1. A first step (step S1) for producing a composite nanofiber assembly including a second nanofiber made of a second polymer having a composite nanofiber at a temperature lower than the first melting point T1 and higher than the second melting point T2. A second step (step S2) of manufacturing a high-strength composite nanofiber aggregate having a structure in which the first nanofibers are partially bonded to each other by the second polymer by heating the aggregate.

  The first melting point T1 and the second melting point T2 preferably have a difference of 10 ° C. or more. This is because if the difference between the first melting point T1 and the second melting point T2 is less than 10 ° C., it is difficult to set the temperature so that only the second nanofibers are melted in a state where the first nanofibers remain, and the melted This is because it becomes difficult to bond the first polymers together by the second polymer.

  In the composite nanofiber assembly manufactured by the first step, the weight of the first nanofiber contained in the composite nanofiber assembly is M1, and the weight of the second nanofiber contained in the composite nanofiber assembly is When M2, it is preferable to satisfy the relationship of “0.01 ≦ M2 / (M1 + M2) ≦ 0.40”.

  The reason why it is preferable to satisfy such a relationship is that when M2 / (M1 + M2) is less than 0.01, bonding between the first nanofibers by the second polymer may be insufficient, This is because if M2 / (M1 + M2) exceeds 0.40, the characteristics of the composite nanofiber assembly may be deteriorated. From this viewpoint, it is preferable to satisfy the relationship of “0.02 ≦ M2 / (M1 + M2) ≦ 0.20”. In particular, when producing a composite nanofiber assembly mainly composed of the first nanofibers by the first polymer, it is more preferable to satisfy the above-described relationship.

  Further, the composite nanofiber assembly produced by the first step has a value of “0.01 ≦ D2 / D1 ≦ when the average diameter of the first nanofibers is D1 and the average diameter of the second nanofibers is D2. It is preferable to satisfy the relationship of “0.50”.

  The reason why it is preferable to satisfy such a relationship is that when D2 / D1 is less than 0.01, bonding between the first nanofibers by the second polymer may be insufficient, and D2 This is because if / D1 exceeds 0.50, the properties of the composite nanofiber assembly may be deteriorated. From this point of view, it is preferable to satisfy the relationship of “0.02 ≦ D2 / D1 ≦ 0.20”. In particular, when producing a composite nanofiber assembly mainly composed of the first nanofibers by the first polymer, it is more preferable to satisfy the above-described relationship.

  Each process in the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly of this invention demonstrated above is common in each embodiment demonstrated below. In addition, in the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly in each embodiment shown below, a polyurethane is used as a 1st polymer and a polyvinylidene fluoride is used as a 2nd polymer.

  According to the method for producing a high-strength composite nanofiber assembly of the present invention, industrial materials such as filters, secondary battery separators, capacitor separators, various catalyst carriers, electronic and mechanical materials such as various sensor materials, and regenerative medical materials , Biomedical materials, medical MEMS materials, medical materials such as biosensor materials, wiping cloth, apparel such as high-functional and high-sensitivity textiles, beauty-related products such as health care and skin care, and high strength that can be used in a wide range of other applications Composite nanofiber assemblies can be produced.

  In addition, the high-strength composite nanofiber assembly of the present invention (high-strength composite nanofiber nonwoven fabric, high-strength composite nanofiber filament) manufactured by the method for manufacturing a high-strength composite nanofiber assembly of the present invention has high mechanical properties. Since it is a high-strength composite nanofiber aggregate having strength, it can be used for a wide range of applications as described above.

[Embodiment 1]
2-6 is a figure shown in order to demonstrate the manufacturing method of the composite nanofiber aggregate | assembly which concerns on Embodiment 1. FIG. 2 is referred to as a composite nanofiber assembly manufacturing apparatus (hereinafter referred to as “composite nanofiber assembly manufacturing apparatus”) for performing the first step in the method of manufacturing a composite nanofiber assembly according to the first embodiment. FIG. In FIG. 2, some members are shown as sectional views. FIG. 3 is a plan view of the nozzle unit 110 used in the composite nanofiber assembly manufacturing apparatus 11. FIG. 4 is a view for explaining the composite nanofiber nonwoven fabric manufactured by the composite nanofiber assembly manufacturing apparatus 11. FIG. 4A is a perspective view showing a part of the composite nanofiber nonwoven fabric, and FIG. 4B is a schematic view showing an enlarged part of the composite nanofiber nonwoven fabric. FIG. 5 shows an apparatus for producing a high-strength composite nanofiber assembly for carrying out the second step shown in FIG. FIG. FIG. 5A is a front view, and FIG. 5B is a plan view. FIG. 6 is an enlarged schematic view showing a part of the high-strength composite nanofiber assembly manufactured by the high-strength composite nanofiber assembly manufacturing apparatus 51.

  The composite nanofiber assembly manufacturing apparatus 11 according to the embodiment includes a transport apparatus 10 and an electrospinning apparatus 20 as shown in FIG.

  The conveying device 10 includes a feeding roller 101 that feeds out the long sheet W, a winding roller 102 that winds up the long sheet W, and auxiliary rollers 103 and 104 that are positioned between the feeding roller 101 and the winding roller 102. The long sheet W is conveyed in the direction of arrow a (referred to as conveyance direction a) at a predetermined conveyance speed. The feed roller 101 and the take-up roller 102 are configured to be rotated by a drive motor (not shown).

  The electrospinning device 20 includes a first nanofiber 310 (see FIG. 4B) made of the first polymer and a second nanofiber 320 made of the second polymer (see FIG. 4B) on the long sheet W being conveyed by the conveying device 10. 4B) is deposited.

  As shown in FIG. 2, the electrospinning device 20 includes a conductive casing 100, a nozzle unit 110, a collector 150, a power supply device 160, an auxiliary belt device 170, a first polymer solution tank 200, A first supply device 210, a second polymer solution tank 220, and a second supply device 230 are provided.

  The first polymer solution tank 200 stores a first polymer solution obtained by melting polyurethane as a first polymer in a solvent. The second polymer solution tank 200 stores a first polymer solution obtained by melting polyvinylidene fluoride as a second polymer in a solvent. The first polymer solution tank 200 and the second polymer solution tank 220 are preferably provided with a stirring device (not shown) for stirring the polymer solution (first polymer solution and second polymer solution).

  In addition, as a solvent for preparing a 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 supply device 210 includes a valve 214 that can control the supply amount of the first polymer solution, and a distribution pipe 212 that distributes the first polymer solution to the nozzle unit 110. Similarly, the second supply device 230 includes a valve 234 capable of controlling the supply amount of the second polymer solution, and a distribution pipe 232 that distributes the second polymer solution to the nozzle unit 110.

  In each of the first polymer solution tank 200 and the first supply device 210 and the second polymer solution tank 220 and the second supply device 230, the respective polymer solutions (the first polymer solution and the second polymer solution) are set to a predetermined temperature (for example, 60). It is preferable to provide a heat retention device (not shown) for keeping the temperature at from 80 ° C. to 80 ° C.

  As illustrated in FIG. 3, the nozzle unit 110 includes a plurality of first nozzles 120, a plurality of second nozzles 130, a first polymer solution supply path 122, and a second polymer solution supply path 132. Further, a first polymer solution recovery path (not shown) for recovering the first polymer solution overflowed from the first nozzle 120 and a second polymer solution recovery path (for recovering the second polymer solution overflowed from the second nozzle 130). (Not shown) may be provided.

  For the composite nanofiber assembly production apparatus 11 of the present invention, nozzle units having various sizes and shapes can be used. For example, the nozzle unit 110 has a side of 0.5 m when viewed from above. It has a size and shape that looks like a rectangle (including a square) of ˜3 m.

  As shown in FIG. 3, the first polymer solution supply path 122 and the second polymer solution supply path 132 of the nozzle unit 110 have a comb shape having a concavo-convex portion, and a convex portion corresponding to a comb tooth, The teeth and the recesses corresponding to the teeth are arranged so as to be combined with each other.

  The first nozzles 120 are arranged at a predetermined pitch along the longitudinal direction of each convex portion of the first polymer solution supply path 122. Similarly, in the second polymer solution supply path 132, the second nozzles 130 are arranged at predetermined pitches along the longitudinal direction of the respective convex portions. Thereby, when the nozzle unit 110 is viewed along the transport direction a, the first nozzles 120 and the second nozzles 130 are alternately arranged.

  The first nozzle 120 and the second nozzle 130 are arranged at a pitch of 1.5 cm to 6.0 cm, for example. The total number of the plurality of first nozzles 120 and the plurality of second nozzles 130 is, for example, 36 (6 × 6 when arranged in the same vertical and horizontal directions) to 21904 (148 when arranged in the same vertical and horizontal numbers) X148).

  The interior of the first nozzle 120 is a cavity, and the cavity communicates with the cavity in the first polymer solution supply path 122. The first nozzle 120 discharges the first polymer solution upward from the discharge port. Similarly, the inside of the second nozzle 120 is a cavity, and the cavity communicates with the cavity in the second polymer solution supply path 122. The second nozzle 120 also discharges the second polymer solution upward from the discharge port.

  The first nozzle 120 and the second nozzle 130 are made of a conductor, and for example, copper, stainless steel, aluminum, or the like can be used. The nozzle unit is also made of a conductor, and the same material as the first nozzle 120 and the second nozzle 130 can be used.

  The inside of the first polymer solution supply path 122 is hollow, and the flow pipe 212 of the first supply device 210 is connected thereto. As a result, the first polymer solution stored in the first polymer solution tank 200 flows through the distribution pipe 212 and flows into the first polymer solution supply path 122 and then is supplied to the first nozzle 120.

  Similarly, the second polymer solution supply path 132 has a hollow inside, and the distribution pipe 232 of the second supply device 220 is connected thereto. Accordingly, the second polymer solution stored in the second polymer solution tank 220 flows through the distribution pipe 232 and flows into the second polymer solution supply path 132 and then is supplied to the second nozzle 130.

  The collector 150 is disposed at a position facing the first nozzle 120 and the second nozzle 130. 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 first nozzle 120 and the second nozzle 130 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 long sheet W, the long sheet W is smoothly conveyed without being attracted to the collector 150 to which a positive high voltage is applied. become.

  The electrospinning apparatus 20 configured as described above discharges the first polymer solution and the second polymer solution from the discharge ports of the plurality of first nozzles 120 and the plurality of second nozzles 130 while overflowing them, thereby forming the first nanofibers. 310 and the second nanofiber 320 are deposited on the long sheet W.

  By using the composite nanofiber assembly manufacturing apparatus 11 as described above, the first step (step S1) in FIG. 1 can be carried out, whereby a composite nanofiber nonwoven fabric 300A as a composite nanofiber assembly is obtained. (See FIG. 4).

  As shown in FIG. 4, the composite nanofiber nonwoven fabric 300A is a composite having first nanofibers 310 made of polyurethane having a first melting point T1 and second nanofibers 320 made of polyvinylidene fluoride having a second melting point T2. Nanofiber nonwoven fabric. The thickness of the composite nanofiber nonwoven fabric 300A is in the range of 1 μm to 100 μm, for example, 50 μm. In FIG. 4, the long sheet W is shown, but the long sheet W may be peeled off.

  In this specification, the composite nanofiber composed of the first nanofiber 310 and the second nanofiber 320 including the long sheet W may be referred to as “composite nanofiber nonwoven fabric”, and the long sheet W is peeled off. The composite nanofiber composed of the first nanofiber 310 and the second nanofiber 320 in a state of being in a state may be referred to as “composite nanofiber nonwoven fabric”.

  The average diameter of the first nanofibers 310 is in the range of 500 nm to 3000 nm, for example, 900 nm. The average diameter of the second nanofiber 320 is in the range of 50 nm to 1000 nm, for example, 100 nm. By setting the average diameters of the first nanofibers 310 and the second nanofibers 320 in this way, the relationship of “0.01 ≦ D2 / D1 ≦ 0.50” can be satisfied.

  In the composite nanofiber nonwoven fabric 300A, the weight M1 of the first nanofiber and the weight M2 of the second nanofiber contained in the composite nanofiber nonwoven fabric 300A are “0.01 ≦ M2 / (M1 + M2) ≦ 0.40. Is preferably satisfied.

  When the composite nanofiber nonwoven fabric 300A is manufactured as described above, a high-strength composite nanofiber nonwoven fabric is manufactured from the composite nanofiber nonwoven fabric 300A using the high-strength composite nanofiber assembly manufacturing apparatus 51 shown in FIG. The second step is performed.

  As shown in FIG. 5, the high-strength composite nanofiber assembly manufacturing apparatus 51 includes a transport device 60 that transports the composite nanofiber nonwoven fabric 300 </ b> A along the transport direction a, and a composite nanofiber nonwoven fabric that is transported by the transport device 60. And a pressurizing / heating device 70 for heating 300A while pressurizing.

  The conveyance device 60 feeds the composite nanofiber nonwoven fabric 300 </ b> A and a take-up roller for winding the composite nanofiber nonwoven fabric (referred to as the high-strength composite nanofiber nonwoven fabric 300 </ b> B) that has been strengthened by the pressurizing / heating device 70. 602, and auxiliary rollers 603 and 604 provided between the feeding roller 601 and the take-up roller 602. In addition to these components, the transport device 60 includes various components such as a driving unit that drives the feeding roller 601 and the take-up roller 602, but these are not shown.

  The pressurizing / heating device 70 is a high-strength composite nanofiber nonwoven fabric by heating the composite nanofiber nonwoven fabric 300 </ b> A being conveyed while pressurizing. Note that a calendar roll 701 can be used as the pressurizing device. Further, the heating device for heating the composite nanofiber nonwoven fabric 300A is not particularly limited, and for example, a heater function (not shown) may be incorporated in the calendar roll 701, and the composite nanofiber nonwoven fabric may be incorporated. A heating device (not shown) for directly heating 300A may be provided. In addition, as the heating device, for example, a resistance heater, an infrared heater, a combustion heater, a dryer, a hot air generator, or the like can be used.

  In addition, it is preferable that the heating temperature T3 when heating the composite nanofiber nonwoven fabric 300A is approximately halfway between the first melting point T1 and the second melting point T2. For example, if the first melting point T1 is 200 degrees and the second melting point T1 is 140 degrees, the heating temperature T3 is preferably about 170 degrees.

  In FIG. 5, the calendar roll 701 is exemplified as having a configuration in which the composite nanofiber nonwoven fabric 300 </ b> A is sandwiched between upper and lower rollers, but is not limited to such a configuration, and the upper and lower two are provided. It is possible to use calendar rolls having various configurations, such as one with each roller.

  In this way, by heating the composite nanofiber nonwoven fabric 300A with the pressurizing / heating device 70 at the heating temperature T3 while applying pressure, a high-strength composite nanofiber nonwoven fabric 300B as shown in FIG. 6 can be manufactured. . 6A shows a case where most of the second nanofibers 320 are melted, and FIG. 6B shows a case where the second nanofibers 320 remain.

  That is, since the heating temperature T3 at the time of pressurizing / heating with the pressurizing / heating device 70 is lower than the first melting point T1 and higher than the second melting point T2, the second nanofiber made of the second polymer. 320 melts. At this time, when the composite nanofiber nonwoven fabric 300A is pressurized, the melted second nanofiber 320 is intertwined with the plurality of first nanofibers 310, 310,..., As shown in FIG. When the first nanofibers 310 are intercalated at each intersection point, and solidify in that state, the first nanofibers 310 are joined by the second nanofiber 320 at each intersection point.

  In FIG. 6, the hatched portion shows a state where the melted second nanofiber is solidified at the intersection of the first nanofibers. As a result, the first nanofibers 310 are partially bonded by the second nanofibers 320. A portion where the first nanofibers 310 are partially bonded by the second nanofiber 320 is referred to as a “bonding portion C”.

  In this way, at each intersection of the first nanofibers 310, 310..., The bonded portions C are formed by the melted second nanofibers 320, and thus the high-strength composite nanofiber nonwoven fabric 300B having high mechanical strength. Can be manufactured. In addition, since the high-strength composite nanofiber nonwoven fabric 300B manufactured by the method for manufacturing the high-strength composite nanofiber nonwoven fabric according to Embodiment 1 has only a partial connection portion C between the first nanofibers 310, The entire high-strength composite nanofiber nonwoven fabric 300B is not stiffened, and a high-strength composite nanofiber nonwoven fabric can be obtained while maintaining the “flexibility” as the composite nanofiber nonwoven fabric to some extent.

  6A shows the case where the second nanofibers 320 other than the bonding portions C of the first nanofibers 310, 310,... Are completely melted, the heating temperature is set to a predetermined temperature. By setting, it is also possible to leave the second nanofibers 320 other than the coupling portions C of the first nanofibers 310, 310,.

  For example, if the heating temperature is set to approximately the same temperature as the melting point T2, the second nanofiber 320 is not completely melted, and there is a high possibility that a part will remain. However, when the composite nanofiber nonwoven fabric 300A is pressurized, a greater pressing force is applied to each intersection of the first nanofibers 310, 310,... Than the other portions. The fibers 320 are easily melted, and the joint C can be formed at each intersection.

  Thereby, for example, as shown in FIG. 6B, the second nanofibers other than the coupling portions C of the first nanofibers 310, 310,... It is possible to manufacture the high-strength composite nanofiber nonwoven fabric 300 </ b> C that remains and has a joint C formed at each intersection of the first nanofibers 310, 310,. In this case, the remaining second nanofiber 320 is in a state of becoming thinner or interrupted as compared to the original second nanofiber 320 (see FIG. 4B).

  Thus, the high-strength composite nanofiber nonwoven fabric 300C with the second nanofibers remaining is different from the high-strength composite nanofiber nonwoven fabric 300B with the second nanofibers completely dissolved. It can be a nanofiber nonwoven fabric.

  In addition, in the 2nd process in the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly which concerns on Embodiment 1 demonstrated above, although it did not specify about presence of the elongate sheet | seat W, when implementing a 2nd process The long sheet W may be present or the long sheet W may be peeled off. This can be arbitrarily selected according to the type of the high-strength composite nanofiber nonwoven fabric to be produced.

[Embodiment 2]
The composite nanofiber assembly manufacturing apparatus 11 in the first embodiment exemplifies the case where there is one electrospinning apparatus 20, but has a plurality of electrospinning apparatuses 20 along the conveyance direction a of the long sheet W. It is good also as such a structure.

  7 and 8 are diagrams for explaining the method of manufacturing the composite nanofiber assembly according to the second embodiment. FIG. 7 is a configuration diagram of the composite nanofiber assembly manufacturing apparatus 12 for performing the first step in the method of manufacturing a composite nanofiber assembly according to the second embodiment. In FIG. 7, some members are shown as sectional views. FIG. 8 is an enlarged cross-sectional view of a part of a composite nanofiber nonwoven fabric 301A as a composite nanofiber assembly manufactured by the composite nanofiber assembly manufacturing apparatus 12.

  As shown in FIG. 7, the composite nanofiber assembly manufacturing apparatus 12 includes a plurality (three) of electrospinning apparatuses 20 along the conveyance direction “a” of the long sheet W. In FIG. 7, the same components as those in FIG. However, the three electrospinning apparatuses 20 are referred to as the electrospinning apparatuses 201, 202, and 203 in order from the front side in the transport direction a.

  The configuration of each electrospinning apparatus 201, 202, 203 is basically the same as that of the electrospinning apparatus shown in FIG. 2, but in the composite nanofiber assembly manufacturing apparatus 12, each electrospinning apparatus 201, 202 and 203 are supplied with either the first polymer solution or the second polymer solution. In this case, the first polymer solution is supplied to the electrospinning apparatus 201, the second polymer solution is supplied to the electrospinning apparatus 201, and the first polymer solution is supplied to the electrospinning apparatus 203. It has become so.

  For this reason, each of the electrospinning apparatuses 201, 202, and 203 is provided with a polymer solution tank that stores a corresponding polymer solution. That is, the electrospinning apparatus 201 and the electrospinning apparatus 203 are provided with a polymer solution tank 200 for storing the first polymer solution, and the electrospinning apparatus 202 has a polymer solution end tank 220 for storing the second polymer solution. Is provided.

  The nozzle units 110 of the electrospinning apparatuses 210, 202, and 203 are not necessarily configured as shown in FIG. 3, and may be configured so that a single polymer solution can be supplied to the nozzles.

  When the first step is performed by the composite nanofiber assembly manufacturing apparatus 12 having the three electrospinning apparatuses 201, 202, and 203 configured as described above, a composite nanofiber nonwoven fabric 301A as shown in FIG. 8 is manufactured. can do. That is, the composite nanofiber nonwoven fabric 301A is formed on the long sheet W by the first nanofiber 310 by the first polymer solution, the second nanofiber 320 by the second polymer solution, and the first polymer solution, as shown in FIG. The first nanofibers 310 are formed. That is, the composite nanofiber nonwoven fabric 301 </ b> A has a sandwich structure in which the second nanofibers 320 are sandwiched between the first nanofibers 310.

  When the composite nanofiber nonwoven fabric 301A is manufactured in this way, a high-strength composite nanofiber nonwoven fabric 301B (not shown) is manufactured from the composite nanofiber nonwoven fabric 301A. The high-strength composite nanofiber nonwoven fabric 301B can be manufactured by performing the second step described in Embodiment 1 using the high-strength composite nanofiber assembly manufacturing apparatus 21 shown in FIG.

  Thus, the high-strength composite nanofiber nonwoven fabric 301B manufactured in the method for manufacturing a composite nanofiber assembly according to Embodiment 2 is the same as the high-strength composite nanofiber manufactured in the method for manufacturing a composite nanofiber assembly according to Embodiment 1. As with the fiber nonwoven fabric 300B (see FIG. 6), the composite nanofiber nonwoven fabric having high mechanical strength in which the intersections of the first nanofibers 310, 310,.

  In addition, although the composite nanofiber assembly manufacturing apparatus 12 in Embodiment 2 has exemplified the case where three electrospinning apparatuses are used, the number of electrospinning apparatuses is not limited to three, and may be two. Further, four or more electrospinning apparatuses may be provided. However, when manufacturing a high-strength composite nanofiber nonwoven fabric mainly composed of the first nanofibers 310 based on the first polymer, the second nanofibers 320 based on the second polymer solution are replaced with the first nanofibers 310 based on the first polymer solution. Since sandwiched sandwich structures are preferable, it is preferable that the number of electrospinning apparatuses is an odd number, such as five or seven.

[Embodiment 3]
In the first embodiment and the second embodiment, the case where a high-strength composite nanofiber non-woven fabric is manufactured as a high-strength composite nanofiber aggregate has been described. However, a high-strength composite nanofiber filament is manufactured as a high-strength composite nanofiber aggregate. can do. Also in this case, the first step (step S1) and the second step (step S2) described in FIG. 1 are performed. However, in the manufacturing method of the high-strength composite nanofiber assembly according to Embodiment 3, in the first step, first, a strip-shaped composite nanofiber nonwoven fabric (referred to as a strip-shaped composite nanofiber nonwoven fabric) is created, and in the second step. A high-strength composite nanofiber filament is produced by heating the strip-shaped composite nanofiber nonwoven fabric while twisting and stretching.

  9-11 is a figure shown in order to demonstrate the manufacturing method of the composite nanofiber aggregate | assembly which concerns on Embodiment 3. FIG. FIG. 9 is a diagram schematically illustrating a main configuration of the composite nanofiber assembly manufacturing apparatus 13 for performing the first step in the method of manufacturing the composite nanofiber assembly according to the third embodiment. ) Is a front view, and FIG. 9B is a plan view. FIG. 10 is a diagram schematically showing a configuration of a high-strength composite nanofiber assembly manufacturing apparatus 52 for performing the second step in the method of manufacturing a composite nanofiber assembly according to the third embodiment. Moreover, FIG. 11 is a figure which shows a mode that the high intensity | strength composite nanofiber filament as a high intensity | strength composite nanofiber aggregate | assembly is manufactured. In addition, in FIG. 11, a mode that a high intensity | strength composite nanofiber filament is manufactured from one strip | belt-shaped composite nanofiber nonwoven fabric among several strip | belt-shaped composite nanofiber nonwoven fabric is shown.

  The composite nanofiber assembly production apparatus 13 shown in FIG. 9 is different from the composite nanofiber assembly production apparatus 11 shown in FIG. 2 in that, in the composite nanofiber assembly production apparatus 13, an electrospinning apparatus 20 and a take-up roller are used. In order to form a strip of the long sheet W take-up roller 105 for winding the long sheet W peeled from the composite nanofiber nonwoven fabric and the composite nanofiber nonwoven fabric 300A from which the long sheet W has been peeled The cutting device 80 is provided, and the other components, which are the same as the composite nanofiber assembly manufacturing apparatus 11 shown in FIG. 2, are given the same reference numerals. In FIG. 9, the electrospinning apparatus 20 has the same configuration as the electrospinning apparatus 20 shown in FIG.

  The cutting device 80 is provided with a plurality of cutting blades 801 at predetermined intervals along the width direction of the composite nanofiber nonwoven fabric, and the composite nanofiber nonwoven fabric 300A is transported in the transport direction a, whereby each cutting is performed. The blade 801 has a structure in which the composite nanofiber nonwoven fabric 300A is cut along the transport direction a. In addition, the width | variety d of each strip | belt-shaped composite nanofiber nonwoven fabric after a cutting | disconnection can come to be set to the arbitrary width within the range of 1 mm-100 mm, for example by adjusting the space | interval of each cutting blade 801. ing.

  With the composite nanofiber assembly manufacturing apparatus 13 configured as described above, the first step for manufacturing the band-shaped composite nanofiber nonwoven fabric can be performed. That is, by electrospinning with the electrospinning apparatus 20, the first nanofibers and the second nanofibers are deposited on the long sheet W to produce the composite nanofiber nonwoven fabric 300A. Subsequently, after peeling the long sheet W from the composite nanofiber nonwoven fabric 300A, the composite nanofiber nonwoven fabric 300A from which the long sheet W has been peeled is shown in FIG. The cutting blade 801 performs an operation of cutting.

  Thereby, a strip-shaped composite nanofiber nonwoven fabric (referred to as strip-shaped composite nanofiber nonwoven fabric 300A1, 300A2,...) Having a predetermined width d is manufactured, and the strip-shaped composite nanofiber nonwoven fabric 300A1, 300A2,. It is wound around the take-up roller 102.

  When the band-shaped composite nanofiber nonwoven fabric is manufactured in this manner, the second step is then performed by the high-strength composite nanofiber assembly manufacturing apparatus 52. In the second step, a high-strength composite nanofiber filament as a high-strength composite nanofiber aggregate is manufactured by heating the band-shaped composite nanofiber nonwoven fabric while twisting and stretching.

  The high-strength composite nanofiber assembly manufacturing apparatus 52 heats the band-shaped composite nanofiber nonwoven fabrics 300A1, 300A2,... While twisting and stretching the high-strength composite nanofiber filaments 300F1, 300F2,. Is to be manufactured.

  As shown in FIG. 10, the high-strength composite nanofiber assembly manufacturing apparatus 52 includes a feeding roller 521 that feeds the strip-shaped composite nanofiber nonwoven fabric 300A1, 300A2,..., And the strip-shaped composite nanofiber nonwoven fabric 300A1, 300A2,. A twisting device 520 that twists the yarn into a “composite nanofiber filament”, a heating device 530 that heats the “composite nanofiber filament” in the process of drawing while feeding by the twisting device 52, and a high strength And a take-up roller 527 for winding the composite nanofiber filament 300F1, 300F2,. Although not shown in FIG. 10, the twisting device 520 and the heating device 530 are provided corresponding to the respective strip-shaped composite nanofiber nonwoven fabrics 300A1, 300A2,.

  As shown in detail in FIG. 11, the twisting device 520 includes a main twisting yarn portion 521 and two yarn feeding devices 522 and 523, and the main twisting yarn portion 521 causes a band-shaped composite nanofiber nonwoven fabric (for example, a band-shaped composite). The nanofiber nonwoven fabric 300A1) is twisted into composite nanofiber filaments, and then fed by the yarn feeders 522 and 523 while twisting from left to right in FIG. Then, the composite nanofiber filament is heated by the heating device 530 during the yarn feeding process.

  Thereby, the “high-strength composite nanofiber filament F1” that is strongly twisted can be continuously produced. Note that, when the yarn is fed by the yarn feeding devices 522 and 523, the yarn feeding speed V1 of the yarn feeding device 523 is faster than the yarn feeding speed V2 of the yarn feeding device 522. Thus, the composite nanofiber filament can be stretched while being fed.

  According to the high-strength composite nanofiber assembly manufacturing apparatus 52 configured as described above, the “high-strength composite nanofiber filaments 300F1, 300F2,...” That are strongly twisted can be continuously manufactured.

  By the way, although the heating apparatus 530 is not specifically limited, For example, a laser beam irradiation apparatus etc. can be used. When the “composite nanofiber filament” twisted by, for example, the twisting device 520 is irradiated with laser light output from the laser light irradiation device, the composite nanofiber filament is irradiated in the region R1 irradiated with the laser light (see FIG. 11). Is heated.

  Here, if the temperature (heating temperature) T3 of the composite nanofiber filament in the region R1 is adjusted so that T1> T3> T2 with respect to the first melting point T1 and the second melting point T2, the laser light irradiation apparatus is adjusted. Only the second nanofiber 320 made of the second polymer melts. At this time, since the composite nanofiber filament is twisted and stretched, the composite nanofiber filament is in a state almost the same as that of being pressurized, and thus is entangled as described in the first embodiment. At each intersection of the plurality of first nanofibers 310, 310,..., A bonded portion C (see FIG. 6) is formed by the solidified molten second nanofiber 320.

  In this case as well, by selecting the heating temperature T3, it is possible to completely dissolve the second nanofiber 320 made of the second polymer other than the bonding portion C, as shown in FIG. Further, as shown in FIG. 6B, it is possible to leave a part.

  By performing the above steps, the manufactured high-strength composite nanofiber filaments 300F1, 300F2,... Are first nanofibers by the second nanofibers 320 at the intersections of the first nanofibers 310, 310,. Since the fibers are partially bonded to each other, even if a tensile stress is applied to the high-strength composite nanofiber filaments 300F1, 300F2,. The nanofiber filament can be made stronger than the nanofiber filament.

  Further, in the high-strength composite nanofiber filaments 300F1, 300F2,... Manufactured by the method for manufacturing the high-strength composite nanofiber aggregate according to Embodiment 3, the joint portion C between the first nanofibers 310 is partially. Because it is only present, the entire high-strength composite nanofiber filament will not be stiffened, and it will be a high-strength composite nanofiber filament while maintaining the suppleness of the composite nanofiber filament to some extent. be able to.

  In the third embodiment, the composite nanofiber nonwoven fabric 300A is manufactured using the composite nanofiber assembly manufacturing apparatus 11 (see FIG. 2) described in the first embodiment, and the composite nanofiber nonwoven fabric 300A is used to produce a band-shaped composite nanofiber. Although the case where a fiber nonwoven fabric was manufactured was illustrated, it is not restricted to this, Composite nanofiber nonwoven fabric 301A is manufactured using the composite nanofiber assembly manufacturing apparatus 12 (refer FIG. 7) demonstrated in Embodiment 2. FIG. A band-shaped composite nanofiber nonwoven fabric may be manufactured from the composite nanofiber nonwoven fabric 301A.

[Embodiment 4]
In the said Embodiment 3, the composite nanofiber assembly manufacturing apparatus 13 for implementing the 1st process (process which manufactures a strip | belt-shaped composite nanofiber nonwoven fabric) first manufactures the sheet-like composite nanofiber nonwoven fabric 300A, The sheet-like composite nanofiber nonwoven fabric 300A is cut by the cutting device 80 to produce the band-shaped composite nanofiber nonwoven fabric 300A1, 300A2,... In Embodiment 4, the electrospinning method is used. The band-shaped composite nanofiber nonwoven fabrics 300A1, 300A2,.

  FIG. 12 is a diagram for explaining the high-strength composite nanofiber assembly manufacturing method according to the fourth embodiment. 12 (a) and 12 (b) are schematic views showing a state where the band-shaped composite nanofiber nonwoven fabrics 300A1, 300A2,... Are manufactured from different angles using the composite nanofiber assembly manufacturing apparatus 14. FIG. FIG. 12 (c) is a diagram showing a strip-shaped composite nanofiber nonwoven fabric 300 </ b> A <b> 1 among the strip-shaped composite nanofiber nonwoven fabrics 300 </ b> A <b> 1, 300 </ b> A <b> 2,.

  The composite nanofiber assembly manufacturing apparatus 14 includes a drum-shaped collector 400 in which a strip-shaped collector 401 extending in the circumferential direction is formed on the outer peripheral surface of the drum as a collector in the electrospinning apparatus 20. Then, the electrospinning is performed in a state where a high voltage is applied between the belt-like collector 401 in the drum-like collector 400 and the first nozzle 120 for discharging the first polymer solution and the second nozzle 130 for discharging the second polymer solution. By performing, the 1st nanofiber 310 which consists of a 1st polymer solution, and the 2nd nanofiber 320 which consists of a 2nd polymer solution are deposited on the strip | belt-shaped collector 401. FIG. Thereby, it becomes possible to manufacture the strip-shaped composite nanofiber nonwoven fabric 300A1, 300A2,... Composed of the first nanofiber and the second nanofiber.

In FIG. 12, only one each of the first nozzle 120 and the second nozzle 130 is shown, but actually there are a plurality of nozzles.
The drum-shaped collector 400 has a configuration in which a disk-shaped conductive disk 403 having a predetermined thickness and a disk-shaped non-conductive disk 404 having a predetermined thickness are alternately stacked on a rotating shaft 402 of a conductive material. Thus, the conductive disk 403 and the non-conductive disk 404 rotate together with the rotating shaft 402. Further, one side of the rotating shaft 402 is connected to the motor 406 via the bearing 405, and the other side of the rotating shaft 402 is connected to the power supply device 160. The bearing 405 is configured so that the motor 406 and the rotary shaft 402 can be electrically insulated.

  The 1st process for manufacturing a strip | belt-shaped composite nanofiber nonwoven fabric using the composite nanofiber assembly manufacturing apparatus 14 comprised in this way is demonstrated.

  When a high voltage is applied between the belt-shaped collector 401 of the drum-shaped collector 400 and the first nozzle 120 and the second nozzle 130 to perform electrospinning, the first nanofibers and the second nanofibers are deposited on the belt-shaped collector 401. To do. At this time, as shown in FIG. 12B, by performing electrospinning while rotating the drum-shaped collector 400 in the direction of the arrow c shown in FIG. The first nanofibers and the second nanofibers can be continuously deposited in the circumferential direction on the outer peripheral surface.

  While performing such electrospinning, the deposited first nanofibers and second nanofibers are wound around the take-up roller 409 via the auxiliary rollers 407 and 408, so that the first nanofibers and the second nanofibers are removed. The resulting strip-shaped composite nanofiber nonwoven fabric 300A1, 300A2,... Can be continuously recovered.

  According to the 1st process in the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly which concerns on Embodiment 4, it becomes possible to manufacture strip | belt-shaped composite nanofiber nonwoven fabric 300A1, 300A2, ... efficiently with high productivity. Moreover, since it becomes strip | belt-shaped composite nanofiber nonwoven fabric 300A1, 300A2, ... from the beginning, the cutting device for setting it as a strip | belt-shaped composite nanofiber nonwoven fabric becomes unnecessary.

  The strip-shaped composite nanofiber nonwoven fabric 300A1, 300A2,... Can be manufactured by the first step described above. And using the said strip | belt-shaped composite nanofiber nonwoven fabric 300A1, 300A2, ..., implementing a 2nd process for manufacturing a high intensity | strength composite nanofiber aggregate | assembly, manufacturing a high intensity | strength composite nanofiber filament. Can do. The second step for manufacturing the high-strength composite nanofiber assembly is the high-strength composite nanofiber assembly manufacturing apparatus 52 (FIG. 10) described in the method for manufacturing a high-strength composite nanofiber assembly according to the third embodiment. )), The description can be omitted here because it can be performed in the same manner as described in FIG.

  As mentioned above, although the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly of this invention was demonstrated based on said each embodiment, this invention is not limited to this, It can implement in the range which does not deviate from the summary. For example, the following modifications are possible.

(1) In each of the above embodiments, the case where polyurethane is used as the first polymer and polyvinylidene fluoride is used as the second polymer is exemplified. However, the present invention is not limited to this, and the melting point and the like have been described in the above embodiment. If various conditions are satisfied, it is possible to use polymers of other materials. For example, polylactic acid (PLA), polypropylene (PP), polyvinyl acetate (PVAc), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyamide (PA), polyvinyl alcohol (PVA) Polyacrylonitrile (PAN), polyetherimide (PEI), polycaprolactone (PCL), polylactic glycolic acid (PLGA), silk, cellulose, chitosan and the like can be used.

(2) In each of the above embodiments, the first polymer and the second polymer are exemplified by using different polymers, but the first polymer and the second polymer are made of different materials. It is not restricted to a certain thing, The polymer which is the polymer of the same material and has a different number average molecular weight may be sufficient. For example, when polyurethane is used as the polymer, two polymers having different number average molecular weights can be used as the first polymer and the second polymer. This is because even if the first polymer and the second polymer are the same material and are the same, the melting point and the like can be made different by different number average molecular weights. Can also be used.

(3) In the first step in Embodiments 1 and 2, a composite nanofiber assembly that manufactures a composite nanofiber nonwoven fabric by depositing the first nanofibers 310 and the second nanofibers 320 on the long sheet W Although the body manufacturing apparatus 11 is illustrated, the present invention is not limited to such a composite nanofiber assembly manufacturing apparatus, and the first nanofibers 310 and the second nanofibers 320 are directly deposited on the collector without using the long sheet W. The composite nanofiber aggregate manufacturing apparatus for manufacturing the composite nanofiber nonwoven fabric may be used. The same applies to the composite nanofiber assembly production apparatus 12 in the third embodiment. In this case, the long sheet W take-up roller 105 for winding the long sheet W is not necessary.

(4) The nozzle unit 110 used in the composite nanofiber assembly manufacturing apparatus 11 in Embodiment 1 is configured as shown in FIG. 3, but is not limited to such a configuration. A plurality of tubes arranged along the width direction of the length sheet W may be arranged in the conveying direction, and a predetermined number of nozzles may be attached to each tube. In this case, the first polymer solution and the second polymer solution are alternately supplied to each tube body. Even with such a configuration, a composite nanofiber nonwoven fabric similar to that of Embodiment 1 can be manufactured. Such a nozzle unit can also be applied to the second and third embodiments.

(5) In each of the above embodiments, the composite nanofiber assembly manufacturing apparatus for performing the first step and the high-strength composite nanofiber assembly manufacturing apparatus for performing the second step are separate devices. Although described, it is also possible to incorporate them in one device. By doing in this way, a 1st process and a 2nd process can be performed in a flow operation with one apparatus.

(6) When the high-strength composite nanofiber assembly of the present invention is used as a separator for a secondary battery, it is preferable to set the second melting point of the second polymer within a range of 150 ° C to 180 ° C. By adopting such a configuration, when the temperature of the separator rises to 150 ° C. to 180 ° C., the second polymer melts and the pores of the separator are blocked, so that the separator shutdown function functions effectively. be able to. In this case, it is preferable that the relationship of “0.40 ≦ M2 / (M1 + M2)” is satisfied, where the weight of the first nanofiber is M1 and the weight of the second nanofiber is M2. In this case, it is preferable to set the first melting point of the first polymer to a temperature of 200 ° C. or higher. By adopting such a configuration, even when the temperature of the separator rises to 150 ° C. to 180 ° C. and the second polymer melts, the first polymer does not melt, so that the thermal contraction of the separator can be kept small. it can.

(7) When the high-strength composite nanofiber assembly of the present invention is used as a separator for a secondary battery, it is also preferable to set the first melting point of the first polymer within a range of 150 ° C to 180 ° C. By adopting such a configuration, when the temperature of the separator rises to 150 ° C. to 180 ° C., the first polymer and the second polymer melt and the pores of the separator are surely blocked. The function can function effectively.

(8) When the high-strength composite nanofiber assembly of the present invention is used as a separator for an in-vehicle secondary battery, both the first melting point of the first polymer and the second melting point of the second polymer are set to 200 ° C. or higher. It is also preferable to do. With such a configuration, even when the temperature of the secondary battery rises to a temperature of about 150 ° C., for example, the separator is not deteriorated, and a highly reliable separator can be configured.

  DESCRIPTION OF SYMBOLS 10,60 ... Conveyance device 11, 12, 13, 14 ... Composite nanofiber assembly manufacturing device, 20, 201, 202, 203 ... Electrospinning device, 51, 52 ... High strength composite Nanofiber assembly manufacturing device, 70 ... Pressurizing / heating device, 80 ... Cutting device, 101 ... Feeding roller, 102 ... Winding roller, 110 ... Nozzle unit, 120 ... -1st nozzle, 130 ... 2nd nozzle, 170 ... Auxiliary belt device, 200 ... 1st polymer solution tank, 220 ... 2nd polymer solution tank, 300A ... Composite nanofiber nonwoven fabric, 300A1, 300A2 ... strip-shaped composite nanofiber nonwoven fabric, 300B ... high-strength composite nanofiber nonwoven fabric, 300F1, 300F2 ... high-strength composite nanofiber filament, 400 ... Dora -Shaped collector, 401 ... strip-shaped collector, 402 ... rotating shaft, 403 ... conductive disk, 404 ... non-conductive disk, 520 ... twisting device, 521 ... main twisting yarn part, 522 , 523 ... Thread feeding device, 530 ... Heating device, 701 ... Calendar roll, 801 ... Cutting blade, a ... Conveying direction, W ... Long sheet

Claims (12)

First manufacturing a composite nanofiber assembly including a first nanofiber made of a first polymer having a first melting point and a second nanofiber made of a second polymer having a second melting point lower than the first melting point Process,
The composite nanofiber assembly is heated to a temperature lower than the first melting point and higher than the second melting point, thereby having a structure in which the first nanofibers are partially bonded by the second polymer. The manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly characterized by including the 2nd process of manufacturing an intensity | strength composite nanofiber aggregate | assembly in this order. In the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly of Claim 1,
In the first step, a composite nanofiber nonwoven fabric is created as the composite nanofiber assembly,
In the second step, a high-strength composite nanofiber nonwoven fabric is produced as the high-strength composite nanofiber aggregate by heating the composite nanofiber nonwoven fabric while applying pressure. Manufacturing method. In the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly of Claim 2,
In the first step, the composite nanofiber nonwoven fabric is produced by electrospinning the first polymer solution containing the first polymer and the second polymer solution containing the second polymer from different nozzles, respectively. A method for producing a high-strength composite nanofiber assembly. In the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly of Claim 1,
In the first step, a band-shaped composite nanofiber nonwoven fabric is created as the composite nanofiber assembly,
In the second step, the high-strength composite nanofiber filament as the high-strength composite nanofiber aggregate is produced by heating the band-shaped composite nanofiber nonwoven fabric while twisting and stretching. A method for producing a high-strength composite nanofiber assembly. In the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly of Claim 4,
In the first step, the composite nanofiber nonwoven fabric is produced by electrospinning the first polymer solution containing the first polymer and the second polymer solution containing the second polymer from different nozzles, respectively. Then, the said composite nanofiber nonwoven fabric is cut | disconnected, and the said strip | belt-shaped composite nanofiber nonwoven fabric is manufactured, The manufacturing method of the high intensity | strength composite nanofiber assembly characterized by the above-mentioned. In the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly of Claim 4,
In the first step, the first polymer solution containing the first polymer and the second polymer solution containing the second polymer are electrospun into a band shape from different nozzles, respectively, to thereby form the band-shaped composite nano-particles. A method for producing a high-strength composite nanofiber assembly, which comprises producing a fiber nonwoven fabric. In the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly in any one of Claims 1-6,
When the weight of the first nanofiber contained in the composite nanofiber assembly is M1, and the weight of the second nanofiber contained in the composite nanofiber assembly is M2, “0.01 ≦ M2 / ( M1 + M2) ≦ 0.40 ”is satisfied. A method for producing a high-strength composite nanofiber assembly. In the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly in any one of Claims 1-7,
High strength characterized by satisfying a relationship of “0.01 ≦ D2 / D1 ≦ 0.50”, where D1 is an average diameter of the first nanofibers and D2 is an average diameter of the second nanofibers A method for producing a composite nanofiber assembly. In the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly in any one of Claims 1-8,
A method for producing a high-strength composite nanofiber assembly, wherein the relationship of “T1−T2 ≧ 10 ° C.” is satisfied, where the first melting point is T1 and the second melting point is T2. In the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly in any one of Claims 1-9,
The method for producing a high-strength composite nanofiber assembly, wherein the first polymer and the second polymer are polymers of different materials. In the manufacturing method of the high intensity | strength composite nanofiber aggregate | assembly in any one of Claims 1-9,
The method for producing a high-strength composite nanofiber assembly, wherein the first polymer and the second polymer are polymers having the same material and different number average molecular weights. A high produced from a composite nanofiber assembly comprising a first nanofiber made of a first polymer having a first melting point and a second nanofiber made of a second polymer having a second melting point lower than the first melting point. A strength composite nanofiber assembly,
A high-strength composite nanofiber assembly having a structure in which the first nanofibers are partially bonded to each other by the second polymer.

Images