Nanofiber nonwoven fabric laminate and method for producing same

Abstract

The purpose of the present invention is to provide a nanofiber nonwoven fabric layered body having superior adhesion between layers. In a nanofiber nonwoven fabric layered body according to the present invention, a nylon nanofiber nonwoven fabric and a protein nanofiber nonwoven fabric are brought into direct contact, layered, and integrated.

Description

[Technical Field]

[0001] The present invention relates to a nanofiber nonwoven fabric laminate having excellent interlayer adhesion and a method for producing the same. [Background technology]

[0002] Nanofiber nonwoven fabrics are made up of fibers with a diameter of 1 μm or less, and therefore break immediately when stretched, resulting in low elongation and making them difficult to handle. For this reason, nanofiber nonwoven fabrics are used attached to a support. However, there has been a demand for using the nanofiber nonwoven fabric alone. In this case, the attached support must be removed and peeled off, but the adhesion between the support and the nanofiber nonwoven fabric is strong, and the nanofiber nonwoven fabric may break during peeling. Furthermore, the desired elongation is often not achieved with nanofiber nonwoven fabric alone.

[0003] For this reason, it has been proposed to crosslink the nanofibers that make up a nanofiber nonwoven fabric with an epoxy compound (Patent Document 1). However, although this method improves the strength of the nanofiber nonwoven fabric, it may make the nanofiber nonwoven fabric rigid, resulting in reduced extensibility and conformability.

[0004] For this reason, Shinwa Co., Ltd., the applicant of the present invention, has proposed a nanofiber nonwoven fabric laminate in which a nylon nanofiber nonwoven fabric and another type of nanofiber nonwoven fabric are laminated together (Patent Document 2).

[0005] [Patent Document 1] JP 2015-143400 A [Patent Document 2] Japanese Patent Publication No. 2020-29053 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention is an improvement of the invention described in Patent Document 2, and aims to provide a nanofiber nonwoven fabric laminate with excellent interlayer adhesion. Another aim is to provide a method for advantageously producing such a nanofiber nonwoven fabric laminate. [Means for solving the problem]

[0007] The present invention relates to a nylon nanofiber nonwoven fabric and specific The above-mentioned problems have been solved by laminating and integrating a nylon nanofiber nonwoven fabric and a protein nanofiber nonwoven fabric. Consists of an artificial fibroin having an amino acid sequence corresponding to SEQ ID NO: 40 The present invention relates to a nanofiber nonwoven fabric laminate in which a protein nanofiber nonwoven fabric is laminated and integrated in direct contact with the nonwoven fabric.

[0008] The present invention also provides a method for producing a nylon nanofiber nonwoven fabric, comprising: Artificial fibroin having an amino acid sequence corresponding to SEQ ID NO: 40 and applying an electrospinning method to a protein solution in which a protein nanofiber is dissolved, thereby accumulating the protein nanofibers on the nylon nanofiber nonwoven fabric to form a laminate of the protein nanofiber nonwoven fabric.

[0009] Hereinafter, embodiments of the present invention will be described in detail.

[0010] The nanofiber nonwoven fabric laminate according to this embodiment is made of nylon nanofiber nonwoven fabric and Consists of an artificial fibroin having an amino acid sequence corresponding to SEQ ID NO: 40The protein nanofibers are laminated together in a state of direct contact with the nylon nanofiber nonwoven fabric. The reason for using a nylon nanofiber nonwoven fabric as one of the nanofiber nonwoven fabrics in this nonwoven fabric laminate is that it has excellent releasability from the support. Specifically, as described below, the nanofiber nonwoven fabric laminate of this embodiment is preferably manufactured using an electrospinning method (also known as an electrospinning method) or a melt-blowing method. Manufacturing a nanofiber nonwoven fabric using these methods generally requires a support for accumulating the nanofibers. When attempting to peel the support after manufacturing, most nanofiber nonwoven fabrics adhere relatively firmly to the support, often resulting in breakage during peeling. However, nylon nanofiber nonwoven fabrics have excellent releasability. While the reason for this excellent releasability is unclear, it is thought to be due to the polarity of nylon, which contains amide bonds. Specifically, nylon nanofibers are likely to crystallize during spinning using electrospinning or melt-blowing, which may prevent them from adhering to the support. Nylon 6 is the most suitable nylon.

[0011] Examples of such carriers include nonwoven fabrics formed by integrating thermoplastic continuous fibers and fusing the thermoplastic continuous fibers together. Particularly preferred are spunbonded nonwoven fabrics, in which the continuous fibers are fused together by thermocompression bonding between a pair of smooth rolls, a pair of textured rolls, or a smooth roll and a textured roll. Because the fibers are continuous, they are less likely to entangle with the nanofibers in the nylon nanofiber nonwoven fabric, and the surface is smoothed by thermocompression, making them easier to peel. Examples of thermoplastic continuous fibers include polypropylene continuous fibers, polylactic acid continuous fibers, and core-sheath conjugate continuous fibers with polyethylene as the sheath component and polypropylene as the core component. When spunbonded nonwoven fabrics made of core-sheath conjugate continuous fibers are thermocompressed, the fusion occurs so that only the sheath component softens or melts. Furthermore, since this carrier can also be used when producing nanofiber nonwoven fabrics by electrospinning, it is preferable that it be hydrophilized to impart electrical conductivity. The hydrophilization treatment may involve adding a hydrophilizing agent such as a surfactant, or introducing hydrophilic groups into the continuous fibers by corona discharge treatment, etc. The support is generally removed when the nanofiber nonwoven fabric laminate is used, but it is also possible to use the laminate with the support still attached.

[0012] The protein nanofiber nonwoven fabric laminated and integrated with the nylon nanofiber nonwoven fabric is composed of an accumulation of protein nanofibers. An artificial protein is used as the protein. Here, artificial proteins include recombinant proteins and synthetic proteins. In other words, in this specification, "artificial protein" refers to a protein produced artificially. An artificial protein may have a domain sequence that is different from the amino acid sequence of a naturally occurring protein, or it may have a domain sequence that is identical to the amino acid sequence of a naturally occurring protein. Furthermore, an "artificial protein" may use the amino acid sequence of a naturally occurring protein as is, or may be a protein whose amino acid sequence has been modified based on the amino acid sequence of a naturally occurring protein (e.g., a protein whose amino acid sequence has been modified by modifying the gene sequence of a cloned naturally occurring protein), or may be a protein artificially designed and synthesized without relying on a naturally occurring protein (e.g., a protein having a desired amino acid sequence obtained by chemically synthesizing a nucleic acid encoding a designed amino acid sequence).

[0013] Among the artificial proteins, artificial fibroin is used. Here, "fibroin" refers to a protein molecule produced by insects such as silkworms or spiders. Fibroin can also refer to a fibrous substance consisting of bundles of fibrils made up of protein molecules, but from this perspective, "fibroin" as used in this specification means a fibroin molecule, i.e., a protein molecule that makes up fibroin. Note that protein molecules are sometimes simply called proteins.

[0014] Artificial fibroin includes modified (recombinant) fibroin and synthetic fibroin. In other words, the term "artificial fibroin" as used herein refers to an artificially produced protein having an amino acid sequence identical or similar to that of a protein produced by insects such as silkworms or spiders. Nanofibers obtained using such artificial fibroin have high strength. In particular, artificial fibroin having an amino acid sequence derived from spider silk produced by spiders can produce nanofibers with even higher strength. Used in the present invention The domain sequence of the artificial fibroin is having an amino acid sequence corresponding to SEQ ID NO: 40 .

[0015] As the artificial fibroin, modified fibroin is preferably used.

[0016] Such modified fibroins include, for example, the modified fibroin (modified spider silk fibroin) described in International Publication No. WO2020 / 067546. That is, suitable examples of modified fibroins include a modified fibroin derived from a major spinal dragline silk protein produced in the major ampullate gland of spiders (first modified fibroin), a modified fibroin having a domain sequence with a reduced content of glycine residues (second modified fibroin), a modified fibroin having a domain sequence with a reduced content of (A)n motifs (third modified fibroin), a modified fibroin having a reduced content of glycine residues and a reduced content of (A)n motifs (fourth modified fibroin), a modified fibroin having a domain sequence including a region with a locally high hydrophobic index (fifth modified fibroin), and a modified fibroin having a domain sequence with a reduced content of glutamine residues (sixth modified fibroin). In the present invention, a modified fibroin having an amino acid sequence corresponding to SEQ ID NO: 40 is used, and therefore, the sixth modified fibroin is employed.

[0029] The sixth modified fibroin The sixth modified fibroin comprises a domain sequence represented by formula 1: [(A)n motif-REP]m and has an amino acid sequence with a reduced content of glutamine residues compared to naturally occurring fibroin. The sixth modified fibroin may have an amino acid sequence in which, compared to naturally occurring fibroin, one or more glutamine residues in REP have been deleted or replaced with other amino acid residues. The "other amino acid residues" may be any amino acid residue other than glutamine residues, but are preferably amino acid residues with a higher hydrophobic index than glutamine residues. The hydrophobic indexes of the amino acid residues are as shown in Table 1 above.

[0030] A more specific example of the sixth modified fibroin is a modified fibroin containing the amino acid sequence shown in SEQ ID NO: 40 or an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 40. The amino acid sequence shown in SEQ ID NO: 40 is a modified fibroin containing the amino acid sequence shown in SEQ ID NO: 32 The amino acid sequence shown in SEQ ID NO: 11 is added to the N-terminus of the amino acid sequence shown in SEQ ID NO: 11.

[0031] Sixth The modified fibroin includes a first modified fibroin, a second modified fibroin, a third modified fibroin, and a fourth modified fibroin. or The modified fibroin may also have the characteristics of the fifth modified fibroin.

[0034] In the nanofiber nonwoven fabric laminate according to this embodiment, the nylon nanofiber nonwoven fabric and the protein nanofiber nonwoven fabric are laminated and integrated together in contact with each other at at least a portion of the lamination interface. That is, the two may simply be laminated directly, but preferably they are entangled with each other at the lamination interface, or are pressure-bonded together in the thickness direction after lamination by pressure. They may also be heated during pressure application to be pressure-bonded together. Furthermore, the nylon nanofiber nonwoven fabric and the protein nanofiber nonwoven fabric may be fused or welded together at the lamination interface by softening, melting, swelling, or dissolving in a solvent or the like of the nanofibers. In either case, nylon and protein both have amide bonds, which provide a high affinity between them, and the amide bonds between nylon and protein are able to interact with each other. Therefore, in a nanofiber nonwoven fabric laminate in which a nylon nanofiber nonwoven fabric and a protein nanofiber nonwoven fabric are laminated together through direct contact, high adhesion is exhibited at the lamination interface between the nylon nanofiber nonwoven fabric and the protein nanofiber nonwoven fabric. The basis weight of the nanofiber nonwoven fabric and the artificial protein nanofiber nonwoven fabric is optional, but to obtain a predetermined tensile strength, a basis weight of 0.10 g / m2 or more is preferred, and a weight of approximately 0.15 to 0.85 g / m2 is more preferred. If the basis weight is too low, the tensile strength will be low and handling will be poor. Furthermore, if the basis weight is too high, the laminate will tend to be rigid.

[0035] In the nanofiber nonwoven fabric laminate, a predetermined support (cover layer) may be laminated on the surface of at least one of the nylon nanofiber nonwoven fabric and the protein nanofiber nonwoven fabric opposite to the laminated side. This support may impart a predetermined function, such as shape or strength, to the nanofiber nonwoven fabric laminate, or may impart a function that the nanofiber nonwoven fabric laminate has. Alternatively, as described above, the support may be a support for nanofiber aggregates when the nylon nanofiber nonwoven fabric or the protein nanofiber nonwoven fabric is produced using a method such as electrospinning or meltblowing.

[0036] The nanofiber nonwoven fabric laminate according to this embodiment is preferably produced using a known electrospinning method or melt-blowing method. A specific example of an electrospinning method is a method using the apparatus shown in FIG. 1 of JP 2016-108695 A. Specifically, the nanofiber nonwoven fabric laminate can be produced using an electrospinning apparatus comprising a spinning electrode, a collecting electrode positioned opposite the spinning electrode, and a carrier placed between the spinning electrode and the collecting electrode, through at least two steps. The first step involves using a spunbond nonwoven fabric or the like as a carrier, and using a nylon solution in which nylon resin present in the spinning electrode is dissolved, to generate nylon nanofibers by the action of an electric field generated between the spinning electrode and the collecting electrode, and accumulating the nylon nanofibers on the carrier to obtain a nylon nanofiber nonwoven fabric. Conventional solvents can be used to dissolve the nylon resin, but a mixed solvent of acetic acid and formic acid is preferred due to its low cost and reduced toxicity.

[0037] In the second step, a laminate in which a support and a nylon nanofiber nonwoven fabric are laminated is used as a laminate support, with the nylon nanofiber nonwoven fabric facing the spinning electrode side, and the nylon nanofiber nonwoven fabric is used as a support. Artificial fibroin having an amino acid sequence corresponding to SEQ ID NO: 40 This is a process in which protein nanofibers are generated from a protein solution in which the above-mentioned is dissolved by the action of an electric field generated between a spinning electrode and a collecting electrode, and the protein nanofibers are accumulated on a nylon nanofiber nonwoven fabric to obtain a protein nanofiber nonwoven fabric. Artificial fibroin having an amino acid sequence corresponding to SEQ ID NO: 40Although conventionally known solvents can be used as the solvent for dissolving the protein nanofiber nonwoven fabric, a mixed solvent of acetic acid and formic acid is preferred because of its low cost and reduced toxicity. The above two steps result in a nanofiber nonwoven fabric laminate in which a nylon nanofiber nonwoven fabric and a protein nanofiber nonwoven fabric are laminated together. A support is attached to the laminate, but this may be peeled off immediately after the second step or at the time of use. In this case, the nylon nanofiber nonwoven fabric exhibits good releasability from the support, which, combined with the excellent mechanical strength of the nanofiber nonwoven fabric laminate, results in the effect of the support being less likely to break when peeled off. When producing a nanofiber nonwoven fabric laminate by known electrospinning or melt-blowing methods, the nylon nanofiber nonwoven fabric may be produced using equipment separate from the equipment used to produce the protein nanofiber nonwoven fabric, or an existing or commercially available nylon nanofiber nonwoven fabric may be used.

[0038] If the laminated integration of the nylon nanofiber nonwoven fabric and the protein nanofiber nonwoven fabric is insufficient, stronger integration can be achieved by applying pressure in the thickness direction after the second step. The pressure may be 0.05 to 0.5 MPa. Heat may also be applied during the application of pressure. The heating temperature may be approximately 30 to 70°C.

[0039] Nanofiber nonwoven fabric laminates can be used in a variety of applications. For example, if a nanofiber nonwoven fabric laminate is relatively thin and has excellent flexibility and extensibility, it can easily follow the movements of the human body and can be used as a base fabric for skin care face masks and the like. Furthermore, since nanofiber nonwoven fabric laminates are an aggregate of nanofibers, they have excellent moisture permeability, waterproofness, and heat retention, and can therefore be used as a material for clothing such as skiing. Furthermore, since the gaps between the nanofibers are very small, they can easily capture minute particles such as dust and can be used as a filter material. When used for such applications, the support may be removed or left attached. If used with the support attached, the support functions as a reinforcing layer. In particular, if a spunbond nonwoven fabric is used as the support, it can also function as a pre-filter layer. [Effects of the Invention]

[0040] In the nanofiber nonwoven fabric laminate according to the present invention, the nylon nanofiber nonwoven fabric and the protein nanofiber nonwoven fabric are laminated and integrated through direct contact, and therefore the interaction between the amide bonds in the nylon and the protein enhances adhesion between the laminated layers. Therefore, the nanofiber nonwoven fabric laminate according to the present invention can be expected to have improved mechanical strength. As a result, peeling between the nonwoven fabric layers can be effectively prevented even when a tensile force is applied in the lamination direction, a shear force is applied to the laminate interface, or the laminate is bent.

[0041] Furthermore, according to the method for producing a nanofiber nonwoven fabric laminate of the present invention, the protein nanofiber nonwoven fabric and the nylon nanofiber nonwoven fabric are laminated using electrospinning, which allows the protein nanofibers and the nylon nanofibers to be more easily integrated with each other in a state of contact over a larger contact area, thereby making it easier to produce a nanofiber nonwoven fabric laminate with excellent adhesion at the laminate interface. [Example]

[0042] The present invention will be described in more detail below with reference to examples, etc. However, the present invention is not limited to the following examples.

[0043] Production of modified fibroin (Synthesis of nucleic acid encoding modified fibroin and construction of expression vector) A modified fibroin having the amino acid sequence shown in SEQ ID NO: 40 was designed. Nucleic acids encoding the designed modified fibroins were then synthesized. An NdeI site was added to the 5' end of the nucleic acid, and an EcoRI site was added downstream of the stop codon. These five nucleic acids were each cloned into a cloning vector (pUC118). The nucleic acids were then excised by restriction enzyme treatment with NdeI and EcoRI, and then recombined into the protein expression vector pET-22b(+) to obtain the respective expression vectors.

[0044] (Expression of modified fibroin) Escherichia coli BLR(DE3) was transformed with the resulting expression vector. The transformed E. coli was cultured in 2 mL of LB medium containing ampicillin for 15 hours. The culture solution was added to 100 mL of seed culture medium (Table 2) containing ampicillin so that the OD600 became 0.005. The culture solution temperature was maintained at 30°C, and flask culture was continued until the OD600 reached 5 (approximately 15 hours), to obtain a seed culture solution.

[0045] [Table 2]

[0046] The seed culture was added to a jar fermenter containing 500 ml of production medium (Table 3) so that the OD600 was 0.05. The culture temperature was maintained at 37°C, and the pH was controlled to a constant 6.9. The dissolved oxygen concentration in the culture was maintained at 20% of the dissolved oxygen saturation concentration.

[0047] [Table 3]

[0048] Immediately after the glucose in the production medium was completely consumed, a feed solution (455 g glucose / L, 120 g yeast extract / L) was added at a rate of 1 mL / min. The culture temperature was maintained at 37°C, and the pH was controlled at 6.9. The culture was continued for 20 hours while maintaining the dissolved oxygen concentration in the culture at 20% of the dissolved oxygen saturation concentration. 1 M isopropyl-β-thiogalactopyranoside (IPTG) was then added to the culture to a final concentration of 1 mM to induce expression of the desired modified fibroin. 20 hours after IPTG addition, the culture was centrifuged and the cells were collected. SDS-PAGE was performed using cells prepared from the culture before and after IPTG addition. Expression of the desired modified fibroin was confirmed by the appearance of a band of the size corresponding to the desired modified fibroin, which was dependent on IPTG addition.

[0049] (Purification of modified fibroin) Two hours after the addition of IPTG, the cells were harvested and washed with 20 mM Tris-HCl buffer (pH 7.4). The washed cells were suspended in 20 mM Tris-HCl buffer (pH 7.4) containing approximately 1 mM PMSF and disrupted using a high-pressure homogenizer (GEA Niro Soavi). The disrupted cells were centrifuged to obtain a precipitate. The resulting precipitate was washed with 20 mM Tris-HCl buffer (pH 7.4) until highly purified. The washed precipitate was suspended in 8 M guanidine buffer (8 M guanidine hydrochloride, 10 mM sodium dihydrogen phosphate, 20 mM NaCl, 1 mM Tris-HCl, pH 7.0) to a concentration of 100 mg / mL and dissolved by stirring at 60°C for 30 minutes. After dissolution, the cells were dialyzed against water using a dialysis tube (Cellulose tube 36 / 32, Sanko Junyaku Co., Ltd.). The white aggregated protein obtained after dialysis was collected by centrifugation. The collected aggregated protein was dehydrated using a freeze-dryer to obtain a freeze-dried powder of modified fibroin.

[0050] Example 1 [First step] A nylon solution was prepared by uniformly dissolving 13 parts by mass of nylon 6 resin in 87 parts by mass of a mixed solvent of acetic acid and formic acid (acetic acid: formic acid = 67 parts by mass: 33 parts by mass). The viscosity of this nylon solution was 200 mPa·s and the electrical conductivity was 0.025 mS / cm. On the other hand, as a support, a spunbond nonwoven fabric (basis weight 60 g / m) consisting of continuous polypropylene fibers accumulated and fused together was used. 2 ) was prepared. Using the nylon solution, carrier, and electrospinning device described above, electrospinning was performed under the following conditions. That is, a carrier was placed between a spinning electrode and a collecting electrode, facing each other, on the spinning electrode side of the collecting electrode, and a direct current voltage of 115 kV was applied between the collecting electrode and the spinning electrode to spin nylon 6 nanofibers from the nylon solution present on the spinning electrode, which were then accumulated on the carrier. Here, the distance between the collecting electrode and the spinning electrode was 180 mm. In this manner, a nylon 6 nanofiber with a basis weight of 0.66 g / m was deposited on the carrier. 2 A nylon 6 nanofiber nonwoven fabric was obtained.

[0051] [Second process] A protein solution (modified fibroin solution) was prepared by uniformly dissolving 15 parts by mass of the modified fibroin obtained above in 85 parts by mass of a mixed solvent of acetic acid and formic acid (acetic acid: formic acid = 50 parts by mass: 50 parts by mass). The viscosity of this protein solution was 530 mPa·s and the electrical conductivity was 0.23 mS / cm. A laminate of the support obtained in the first step and nylon 6 nanofiber nonwoven fabric was prepared as a laminated support. Using the above protein solution, laminated support, and electrospinning device, electrospinning was performed under the following conditions: The laminated support was placed between the opposing spinning electrode and collecting electrode, on the spinning electrode side of the collecting electrode (with the nylon 6 nanofiber nonwoven fabric of the laminated support facing the spinning electrode). A DC voltage of 80 kV was applied between the collecting electrode and spinning electrode. Protein nanofibers were spun from the protein solution present on the spinning electrode and accumulated on the nylon 6 nanofiber nonwoven fabric of the laminated support. The distance between the collecting electrode and the spinning electrode was 180 mm. In this manner, a protein nanofiber nonwoven fabric with a basis weight of 3.58 g / m2 was laminated on the nylon 6 nanofiber nonwoven fabric of the laminated support.

[0052] Through the above first and second steps, a nanofiber nonwoven fabric laminate was obtained in which a nylon 6 nanofiber nonwoven fabric and a protein nanofiber nonwoven fabric were laminated together. A support was attached to the other side of the nylon 6 nanofiber nonwoven fabric of this laminate. The basis weight of the nanofiber nonwoven fabric laminate from which the support was removed was 4.24 g / m. 2 The thickness was 0.058 mm.

[0053] Five test pieces, each 8 mm wide and 20 mm long, were taken from the nanofiber nonwoven fabric laminate obtained in Example 1 from which the support had been removed. A tensile test was conducted on each test piece at a chuck distance of 10 mm and a tensile speed of 10 mm / min. The results showed an average breaking strength of 1.15 N and an average breaking stress (stress at break) of 2.48 MPa. This demonstrates that the nanofiber nonwoven fabric laminate obtained in this example has excellent mechanical strength.

Claims

1. A nanofiber nonwoven fabric laminate in which a nylon nanofiber nonwoven fabric and a protein nanofiber nonwoven fabric made of artificial fibroin having an amino acid sequence corresponding to SEQ ID NO: 40 are laminated together in direct contact with each other.

2. 2. The nanofiber nonwoven fabric laminate according to claim 1, wherein the nylon nanofiber nonwoven fabric is a nylon 6 nanofiber nonwoven fabric.

3. The nanofiber nonwoven fabric laminate according to claim 1, wherein a carrier is attached to the surface of the nylon nanofiber nonwoven fabric.

4. The nanofiber nonwoven fabric laminate according to claim 3, wherein the support is a nonwoven fabric formed by accumulating thermoplastic continuous fibers, the thermoplastic continuous fibers being fused to each other.

5. Preparing a nylon nanofiber nonwoven fabric; A step of applying an electrospinning method to a protein solution in which an artificial fibroin having an amino acid sequence corresponding to SEQ ID NO: 40 is dissolved, and accumulating protein nanofibers on the nylon nanofiber nonwoven fabric to form a laminated protein nanofiber nonwoven fabric; A method for producing a nanofiber nonwoven fabric laminate, comprising:

6. 6. The method for producing a nanofiber nonwoven fabric laminate according to claim 5, wherein the nylon nanofiber nonwoven fabric is produced by applying an electrospinning method to a nylon solution in which a nylon resin is dissolved.

7. 7. The method for producing a nanofiber nonwoven fabric laminate according to claim 6, wherein the nylon nanofiber nonwoven fabric is produced by applying an electrospinning method to a nylon solution in which a nylon resin is dissolved, and accumulating nylon nanofibers on a support.

8. The method for producing the nanofiber nonwoven fabric laminate according to claim 7, further comprising the step of removing the support.

9. The method for producing a nanofiber nonwoven fabric laminate according to claim 6, wherein the solvent for each of the nylon solution and the protein solution is a mixed solvent of acetic acid and formic acid.

10. The method for producing the nanofiber nonwoven fabric laminate according to claim 5, further comprising a step of pressing the nanofiber nonwoven fabric laminate in the thickness direction.

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