WO2021241683A1

WO2021241683A1 - Nonwoven fabric, and method for producing same

Info

Publication number: WO2021241683A1
Application number: PCT/JP2021/020191
Authority: WO
Inventors: 亮高岡; 希安藤; 喬太福井; 明彦尾関
Original assignee: シンワ株式会社; Ｓｐｉｂｅｒ株式会社
Priority date: 2020-05-28
Filing date: 2021-05-27
Publication date: 2021-12-02
Also published as: EP4159907A1; US20230212798A1; JPWO2021241683A1; CN116249806A

Abstract

An objective of the present invention is to provide a nonwoven fabric that is not susceptible to liquid being dispersed in the direction of the surface and that can absorb and transmit liquid in a spotwise manner, i.e. has excellent spot absorbency. A nonwoven fabric according to the present invention is formed by mixing artificial protein fibers and hydrophobic synthetic fibers.

Description

Nonwoven fabric and its manufacturing method

The present invention relates to a non-woven fabric having excellent absorption characteristics of liquids such as body fluids and water and a method for producing the same. It is related to the manufacturing method.

Conventionally, a non-woven fabric that is soft to the touch has been used as a surface material for sanitary materials such as sanitary napkins and disposable diapers. Nonwoven fabrics used as surface materials for sanitary materials are required to have excellent properties of so-called spot absorption, which facilitates absorption and permeation of body fluids and makes it difficult for body fluids to diffuse in the surface direction. Various studies have been made to improve spot absorption, and for example, a non-woven fabric made by mixing short fibers, long fibers, and lumpy particles has been proposed (Patent Document 1).

Japanese Unexamined Patent Publication No. 2008-125062

An object of the present invention is to provide a nonwoven fabric having excellent spot absorption and a method capable of advantageously producing such a nonwoven fabric in a simpler process.

As a result of various studies to solve the above problems, the present inventors have excellent spot absorption in a non-woven fabric in which artificial protein fibers containing artificial fibroin and hydrophobic synthetic fibers are mixed (mixed). I found that it could be realized.

That is, the present invention relates to a nonwoven fabric having excellent liquid absorption characteristics, which has been completed based on the above findings and has a region formed by mixing artificial protein fibers containing artificial fibroin and hydrophobic synthetic fibers. It is a thing.

The present invention also relates to a method for producing a nonwoven fabric, which comprises a step of mixing an artificial protein fiber containing artificial fibroin and a hydrophobic synthetic fiber.

Hereinafter, embodiments for carrying out the present invention will be described in detail. The present invention is not limited to the following embodiments.

The non-woven fabric according to the present embodiment is composed of a mixture (mixed) of artificial protein fibers containing artificial fibroin and hydrophobic synthetic fibers. It is preferable that all of the artificial proteins of the artificial protein fibers constituting such a non-woven fabric are artificial fibroin, but natural or artificial proteins other than artificial fibroin and various types are used as long as the effects exhibited by the non-woven fabric of the present invention are not impaired. Additives may be included. Further, the artificial protein fiber may be a short fiber or a long fiber. Further, the artificial protein fiber may or may not be crimped as long as it can form a nonwoven fabric.

As used herein, "fibroin" means a protein molecule produced by insects such as silk moths or spiders. Fibroin may mean a fibrous bundle of fibrils composed of protein molecules, but from this point of view, "fibroin" as used herein refers to a fibroin molecule, that is, fibroin. It means a constituent protein molecule. In addition, a protein molecule may be simply referred to as a protein.

Artificial fibroin contains modified (recombinant) fibroin and synthetic fibroin. That is, the term "artificial fibroin" as used herein means an artificially produced protein having an amino acid sequence equivalent to or similar to that produced by insects such as silk moths or spiders. The artificial fibroin may be a fibroin whose domain sequence is different from the amino acid sequence of naturally occurring fibroin, or may be a protein having the same amino acid sequence as naturally occurring fibroin. In other words, such artificial fibroin may be artificially produced by utilizing the amino acid sequence of naturally occurring fibroin as it is, or the amino acid sequence thereof is modified based on the amino acid sequence of naturally occurring fibroin (for example). , The amino acid sequence may be modified by modifying the gene sequence of the cloned naturally occurring fibroin, or artificially designed and synthesized regardless of the naturally occurring fibroin (eg, designed amino acid). It may have a desired amino acid sequence by chemically synthesizing the nucleic acid encoding the sequence).

Modified fibroin is preferably used as the artificial fibroin contained in the artificial protein fiber which is the constituent material of the non-woven fabric according to the present embodiment. Among them, modified fibroin having an amino acid sequence derived from spider silk, so-called modified spider silk fibroin, is used. It is more preferably used.

Examples of such modified fibroin include modified fibroin (modified spider silk fibroin) described in International Publication No. WO2020 / 0675446. That is, as a preferable example of the modified fibroin, the modified fibroin (first modified fibroin) derived from the large spitting tube bookmark thread protein produced in the large bottle-shaped gland of the spider, and the domain having a reduced content of glycine residue. Modified fibroin having a sequence (second modified fibroin), (A) modified fibroin having a domain sequence having a reduced content of n motif (third modified fibroin), content of glycine residue, and (A). Modified fibroin with reduced n-motif content (fourth modified fibroin), modified fibroin with a domain sequence that locally contains a region with a high hydrophobicity index (fifth modified fibroin), and inclusion of glutamine residues. Examples include modified fibroin (sixth modified fibroin) having a reduced amount of domain sequence.

First Modified Fibroin Examples of the first modified fibroin include proteins containing a domain sequence represented by the formula 1: [(A) n motif-REP] m. In formula 1, the (A) n motif represents an amino acid sequence composed of 3-20 amino acid residues, and the number of alanine residues is 83% or more of the total number of amino acid residues in the (A) n motif. Formula 1: The total number of glycine residues, serine residues and alanine residues contained in the amino acid sequence represented by [(A) n motif-REP] m is 40 with respect to the total number of amino acid residues. % Or more. REP shows an amino acid sequence consisting of 10-200 amino acid residues. m represents an integer of 8-300. The plurality of (A) n motifs may have the same amino acid sequence or different amino acid sequences. The plurality of REPs may have the same amino acid sequence or different amino acid sequences.

The first modified fibroin contains the unit of the amino acid sequence represented by the formula 1: [(A) n motif-REP] m, and the C-terminal sequence is the amino acid sequence shown in any of SEQ ID NOs: 1 to 3 or the amino acid sequence. It may be a polypeptide having an amino acid sequence having 90% or more homology with the amino acid sequence shown in any of SEQ ID NOs: 1 to 3. As a specific example of such a first modified fibroin, 90% or more sequence identity with the amino acid sequence shown by SEQ ID NO: 4 (recombinant spider silk protein ADF3KaiLargeNRSH1) or the amino acid sequence shown by SEQ ID NO: 4 Examples thereof include modified fibroin containing an amino acid sequence having. The sequence identity is preferably 95% or higher. Further, the first modified fibroin may consist of the amino acid sequence shown in SEQ ID NO: 4. The amino acid sequence represented by SEQ ID NO: 4 is the amino acid sequence of ADF3 in which the amino acid sequence (SEQ ID NO: 5) consisting of a starting codon, a His10 tag and an HRV3C protease (Human rhinovirus 3C protease) recognition site is added to the N-terminal. The repeating regions 1 to 13 are increased to be approximately doubled, and the translation is mutated to terminate at the 1154th amino acid residue. The amino acid sequence at the C-terminal of the amino acid sequence shown in SEQ ID NO: 4 is the same as the amino acid sequence shown in SEQ ID NO: 3.

Second Modified Fibroin The second modified fibroin comprises a domain sequence represented by the formula 1: [(A) n motif-REP] m, the domain sequence of which is at least REP as compared to naturally occurring fibroin. It has an amino acid sequence with a reduced content of glycine residues, which corresponds to the substitution of one or more glycine residues in it with another amino acid residue.

As a more specific example of the second fibroin, 90% or more of the amino acid sequence shown by SEQ ID NOs: 6 to 10 and 12 to 16 or the amino acid sequence shown by SEQ ID NO: 6 to 10 and 12 to 16 is identical. Examples thereof include modified fibroin containing an amino acid sequence having sex. The amino acid sequences shown by SEQ ID NOs: 12, 13, 14, 15, and 16 are the amino acid sequences shown by SEQ ID NO: 11 at the N-terminal of the amino acid sequences shown by SEQ ID NOs: 6, 7, 8, 9, and 10, respectively. Amino acid sequence including tag sequence and hinge sequence) is added.

Third Modified Fibroin The third modified fibroin contains a domain sequence represented by the formula 1: [(A) n motif-REP] m, the domain sequence of which is compared to that of naturally occurring fibroin (A). ) It has an amino acid sequence in which the content of n motifs is reduced. It can be said that the domain sequence of the third modified fibroin has an amino acid sequence corresponding to the deletion of at least one or more (A) n motifs as compared with the naturally occurring fibroin.

As a more specific example of the third modified fibroin, the amino acid sequence shown by SEQ ID NO: 7, 8, 9, 17, 13, 14, 15, 18 or SEQ ID NO: 7, 8, 9, 17, 13, 14 , 15, 18, a modified fibroin containing an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown. The amino acid sequences shown in SEQ ID NOs: 13, 14, 15 and 18, respectively, are obtained by adding the amino acid sequence shown in SEQ ID NO: 11 to the N-terminal of the amino acid sequences shown in SEQ ID NOs: 7, 8, 9 and 17, respectively. ..

Fourth Modified Fibroin The fourth modified fibroin contains a domain sequence represented by the formula 1: [(A) n motif-REP] m and contains (A) n motif as compared to naturally occurring fibroin. In addition to having a reduced amount, it has an amino acid sequence with a reduced content of glycine residues. The domain sequence of the fourth modified fibroin lacks at least one or more (A) n motifs as compared to naturally occurring fibroin, plus at least one or more glycine residues in the REP. It can be said that it has an amino acid sequence corresponding to being substituted with another amino acid residue. That is, the fourth modified fibroin is a modified fibroin having the characteristics of the above-mentioned second modified fibroin and the third modified fibroin. Specific embodiments and the like are as described in the second modified fibroin and the third modified fibroin.

As a more specific example of the fourth modified fibroin, the amino acid sequence set forth in SEQ ID NO: 7, 8, 9, 13, 14, 15 or the amino acid set forth in SEQ ID NO: 7, 8, 9, 13, 14, 15 Examples thereof include modified fibroin containing an amino acid sequence having 90% or more sequence identity with the sequence.

Fifth Modified Fibroin The fifth modified fibroin contains a domain sequence represented by the formula 1: [(A) n motif-REP] m, the domain sequence of which is in REP as compared to naturally occurring fibroin. Corresponds to the fact that one or more amino acid residues in 1 or more are replaced with amino acid residues having a large hydrophobicity index, and / or that one or more amino acid residues having a large hydrophobicity index are inserted in REP. It has an amino acid sequence that locally contains a region with a large hydrophobicity index. Amino acid residues having a large hydrophobicity index are amino acid residues selected from isoleucine (I), valine (V), leucine (L), phenylalanine (F), cysteine (C), methionine (M) and alanine (A). Is preferable, and valine (V), leucine (L) and isoleucine (I) are more preferable.

Regarding the hydrophobicity index of amino acid residues, a known index (Hydrotherapy index: Kyte J, & Dollittle R (1982) “A simple method for dispensing the hydropathic protein, lip. 105-132) is used. Specifically, the hydrophobicity index of each amino acid (hydropathy index, hereinafter also referred to as “HI”) is as shown in Table 1 below.

A more specific example of the fifth modified fibroin comprises an amino acid sequence set forth in SEQ ID NOs: 19-24 or an amino acid sequence having 90% or more sequence identity with the amino acid sequence set forth in SEQ ID NOs: 19-24. Modified fibroin can be mentioned. The amino acid sequences shown in SEQ ID NOs: 22, 23, and 24, respectively, are obtained by adding the amino acid sequence shown in SEQ ID NO: 11 to the N-terminal of the amino acid sequences shown in SEQ ID NOs: 19, 20, and 21, respectively.

Sixth Modified Fibroin The sixth modified fibroin contains a domain sequence represented by the formula 1: [(A) n motif-REP] m and has a glutamine residue content as compared with naturally occurring fibroin. It has a reduced amino acid sequence. The sixth modified fibroin corresponds to its domain sequence being deleted from one or more glutamine residues in REP or replaced with other amino acid residues as compared to naturally occurring fibroin. It may have an amino acid sequence. The "other amino acid residue" may be an amino acid residue other than the glutamine residue, but is preferably an amino acid residue having a larger hydrophobicity index than the glutamine residue. The hydrophobicity index of the amino acid residue is as shown in Table 1 above.

As a more specific example of the sixth modified fibroin, the amino acid sequences shown by SEQ ID NOs: 25 to 32, 41, 42, 33 to 40, 43, 44, or SEQ ID NOs: 25 to 32, 41, 42, 33 to 40. , 43, 44 can be mentioned as a modified fibroin comprising an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown. The amino acid sequences shown in 33 to 40, 43 and 44, respectively, are obtained by adding the amino acid sequence shown in SEQ ID NO: 11 to the N-terminal of the amino acid sequences shown in SEQ ID NOs: 25 to 32, 41 and 42, respectively.

The modified fibroin is at least two or more of the characteristics of the first modified fibroin, the second modified fibroin, the third modified fibroin, the fourth modified fibroin, the fifth modified fibroin, and the sixth modified fibroin. It may be a modified fibroin having the above-mentioned characteristics.

The modified fibroin may be a hydrophilic modified fibroin or a hydrophobic modified fibroin. In the present specification, "hydrophilic modified fibroin" is a value obtained by obtaining the total hydrophobicity index (HI) of all amino acid residues constituting the modified fibroin, and then dividing the total by the total number of amino acid residues. It is a modified fibroin having (average HI) of 0 or less. The hydrophobicity index is as shown in Table 1 above. Further, the "hydrophobic modified fibroin" is a modified fibroin having an average HI of more than 0. Examples of the hydrophilic modified fibroin include those included in the definition of the first to fourth modified fibroin described above, and the hydrophobic modified fibroin includes those included in the definition of the fifth and sixth modified fibroin described above. Can be mentioned.

The modified fibroin contained in the artificial protein fiber of the non-woven fabric according to the present embodiment may be modified fibroin having an average HI of −1.0 or more (hydrophilic modified fibroin and hydrophobic modified fibroin), and the average HI is −. It may be a modified fibroin of 0.8 or more (hydrophilic modified fibroin and a hydrophobic modified fibroin), or may be a modified fibroin having an average HI of more than 0 (hydrophobic modified fibroin). When the modified fibroin contained in the artificial protein fiber has an average HI of -1.0 or more or -0.8 or more, more sufficient water absorption may be obtained, and the average HI is If it is more than 0, diffusion in the plane direction may be suppressed more effectively.

As a method for forming an artificial protein fiber using artificial fibroin, a known method such as the method described in International Publication No. WO2020 / 0675446 (for example, dry wet spinning method, wet spinning method, wet spinning method, etc.) is adopted. do it. That is, an artificial protein fiber may be obtained by ejecting a spinning liquid in which artificial fibroin is dissolved from a nozzle to form fibers. Further, artificial fibroin may be mixed with other proteins, polymer polymers, various additives and the like, and the dissolved spinning liquid may be discharged from a nozzle to form fibers to obtain artificial protein fibers. The form of the artificial protein fiber containing the artificial fibroin may be a short fiber or a long fiber. Further, the fineness of the artificial protein fiber containing artificial fibroin is arbitrary, for example, about 1 to 10 decitex.

The synthetic fiber constituting the non-woven fabric according to the present embodiment together with the artificial protein fiber is hydrophobic. Adopting a hydrophilic synthetic fiber is not preferable because the spot absorbability of the obtained non-woven fabric is lowered. The hydrophobic synthetic fiber is preferably a synthetic fiber having an official moisture content of less than 2%. When the official moisture content exceeds 2%, the spot absorbability of the obtained nonwoven fabric tends to decrease. The official moisture content of the hydrophobic synthetic fiber is preferably 1.5% or less, more preferably 1.0% or less, still more preferably 0.5% or less. The lower the official moisture content, the higher the spot absorption of the non-woven fabric may be. Specific examples of the hydrophobic synthetic fiber include polyester fiber such as polyethylene terephthalate fiber, polyolefin fiber such as polypropylene fiber, biodegradable fiber such as polylactic acid fiber, and elastic fiber such as polyurethane fiber. The fibers can be used alone or in combination (combined) as appropriate. The form of the hydrophobic synthetic fiber may be short fiber or long fiber. The fineness of the hydrophobic synthetic fiber is also arbitrary, for example, about 1 to 10 decitex.

The nonwoven fabric according to the present embodiment has a region formed by mixing artificial protein fibers and hydrophobic synthetic fibers. Then, spot absorbability is developed in this region. Such a region may be the entire region of the nonwoven fabric or a partial region. In particular, when artificial protein fibers and hydrophobic synthetic fibers are mixed in all regions of the nonwoven fabric, spot absorption is exhibited in any region of the nonwoven fabric, which is preferable. Although the reason why the excellent spot absorption is obtained in such a non-woven fabric is not clear, the inclusion of the artificial protein fiber makes it possible to secure sufficient water absorption of the artificial protein fiber and the artificial protein fiber. It is considered that the mixing of the hydrophobic synthetic fiber and the hydrophobic synthetic fiber suppresses the occurrence of the capillary phenomenon occurring between the fibers and suppresses the diffusion of water in the plane direction.

In the non-woven fabric according to the present embodiment, the spot absorption is better developed when the degree of mixing of the artificial protein fiber and the hydrophobic synthetic fiber is relatively uniform. Further, the mixed region of the artificial protein fiber and the hydrophobic synthetic fiber may be provided in a part of the nonwoven fabric, and may be provided in a stripe shape in the longitudinal direction or the width direction of the nonwoven fabric, for example. The region other than the mixed region may be composed of only artificial protein fibers, hydrophobic synthetic fibers, or other fibers. The mixing ratio of the artificial protein fiber and the hydrophobic synthetic fiber is arbitrary, but it is sufficient that 10 to 90% by mass of the artificial protein fiber is mixed in the mixed region. When the mixing ratio of artificial protein fibers is less than 10% by mass, that is, when the mixing ratio of hydrophobic synthetic fibers is more than 90% by mass, or when the mixing ratio of artificial protein fibers is more than 90% by mass, that is, hydrophobic. When the mixing ratio of the sex synthetic fiber is less than 10% by mass, the mixing of the artificial protein fiber and the hydrophobic synthetic fiber may be insufficient, and it may be difficult to obtain the desired spot absorbability. .. From that point, the mixing ratio of the artificial protein fiber and the hydrophobic synthetic fiber is generally: artificial protein fiber: hydrophobic synthetic fiber = 10 to 90% by mass: 90 to 10% by mass (total 100% by mass). It is preferably 30 to 70% by mass: 70 to 30% by mass (total 100% by mass), and more preferably 40 to 60% by mass: 60 to 40% by mass (total 100% by mass). good. Too few artificial protein fibers tend to reduce the ability to absorb liquids, and too many artificial protein fibers tend to reduce spot absorbability.

The nonwoven fabric according to this embodiment is produced by mixing artificial protein fiber containing artificial fibroin and hydrophobic synthetic fiber. The method for producing a nonwoven fabric by mixing artificial protein fibers and hydrophobic synthetic fibers is not particularly limited, and any known method can be adopted. That is, the nonwoven fabric according to the present embodiment can be specifically manufactured by a conventionally known manufacturing method such as a spunlace method, a needle punching method, or a thermal bond method. A typical manufacturing method is the following spunlace method. First, the artificial protein fiber and the hydrophobic synthetic fiber are uniformly mixed and passed through a card machine to obtain a fiber web. A high-pressure water stream is applied to the fiber web to entangle the artificial protein fiber and the hydrophobic synthetic fiber, and then the fiber web is dried to obtain the nonwoven fabric according to the present invention. If such a spunlace method is adopted, the artificial protein fiber and the hydrophobic synthetic fiber are strongly entangled, and a non-woven fabric having high tensile strength can be obtained without using an adhesive or the like.

The non-woven fabric according to this embodiment can be used for various purposes. Specifically, it is used as a surface material or a wiping cloth for sanitary materials such as scratch pads, sanitary napkins and disposable diapers.

The nonwoven fabric according to the present invention has the effect of being excellent in spot absorption and having high water absorption capacity. In addition, since the non-woven fabric contains artificial protein fibers, it also has the effect of being good on the skin. Further, according to the manufacturing method according to the present invention, the manufacturing process is simplified, whereby easy manufacturing becomes possible, and improvement in productivity can be desired.

Hereinafter, the present invention will be described more specifically based on examples and the like. However, the present invention is not limited to the following examples.

(1) Production of modified fibroin (synthesis of nucleic acid encoding modified fibroin and construction of expression vector)
Modified fibroin 1 having the amino acid sequence set forth in SEQ ID NO: 40 (mean hydrobacy index: 0.466) and modified fibroin 2 having the amino acid sequence set forth in SEQ ID NO: 15 (mean hydrobacy index: −0.801). Designed.

Nucleic acids encoding the two designed modified fibroins were synthesized respectively. NdeI sites were added to the nucleic acid at the 5'end, and EcoRI sites were added downstream of the stop codon. Each of these five types of nucleic acids was cloned into a cloning vector (pUC118). Then, the nucleic acid was cut out by restriction enzyme treatment with NdeI and EcoRI, and then recombinant into the protein expression vector pET-22b (+) to obtain each expression vector.

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

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

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

(Purification of modified fibroin)
The cells recovered 2 hours after the addition of IPTG were 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 about 1 mM PMSF, and the cells were disrupted with a high-pressure homogenizer (GEA Niro Soavi). The crushed cells were centrifuged to obtain a precipitate. The resulting precipitate was washed with 20 mM Tris-HCl buffer (pH 7.4) until high purity. The washed precipitate was suspended in 8M guanidine buffer (8M guanidine hydrochloride, 10 mM sodium dihydrogen phosphate, 20 mM NaCl, 1 mM Tris-HCl, pH 7.0) to a concentration of 100 mg / mL at 60 ° C. Stir with a stirrer for 30 minutes to dissolve. After dissolution, dialysis was performed with water using a dialysis tube (cellulose tube 36/32 manufactured by Sanko Junyaku Co., Ltd.). The white aggregated protein obtained after dialysis was recovered by centrifugation. Moisture was removed from the collected aggregated protein with a freeze-dryer to obtain freeze-dried powders of two types of modified fibroin 1 and 2 having different amino acid sequences.

(2) Production of artificial protein fiber (preparation of doping solution)
Dimethyl sulfoxide (DMSO) in which LiCl was dissolved to 4.0% by mass was prepared as a solvent, and lyophilized powder of modified fibroins 1 and 2 was added thereto to a concentration of 18% by mass or 24% by mass. And dissolved for 3 hours using a shaker. Then, insoluble matter and bubbles were removed to obtain two kinds of modified fibroin solutions.

(spinning)
Each of the two types of modified fibroin solutions obtained was used as a doping solution (spinning stock solution), and dry-wet spinning and stretching were performed using a known dry-wet device, and two types of artificial protein fibers containing two types of modified fibroin were used. Manufactured. Then, the artificial protein fibers 1 and 2 were wound around a bobbin, respectively. Of these two types of artificial protein fibers, the one containing the modified fibroin 1 was designated as the artificial protein fiber 1, and the one containing the modified fibroin 2 was designated as the artificial protein fiber 2. The conditions for dry-wet spinning are as follows.
Coagulant (methanol) temperature: 5-10 ° C
Stretching ratio: 4.52 times Drying temperature: 80 ° C

Next, the artificial protein fibers 1 and 2 obtained as described above and wound around the bobbin are each pulled out from the bobbin, bundled in groups of one, and cut to a length of 50 mm with a desktop fiber cutting machine. Artificial protein short fibers 1 and a large number of artificial protein short fibers 2 were prepared respectively. Then, the two types of artificial protein 1 and the artificial protein short fiber 2 are each immersed in water at 40 ° C. for 1 minute to be crimped to be crimped, and then dried at 40 ° C. for 18 hours to be crimped. A large number of crimped artificial protein short fibers 1 and a large number of crimped artificial protein fibers 2 were obtained. The fineness of these two types of artificial protein short fibers 1 and 2 was about 1.4 to 1.8 decitex.

Example 1
As a hydrophobic synthetic fiber, a polyester fiber having a fineness of 1.6 decitex and a fiber length of 51 mm (“Tetron T471” manufactured by Toray Industries, Inc.) was prepared. The official moisture content of this polyester fiber is about 0.4%. Then, 50% by mass of the crimped artificial protein short fiber 1 containing the modified fibroin 1 having the amino acid sequence of SEQ ID NO: 40 obtained as described above and 50% by mass of the polyester fiber were uniformly mixed. After that, I got a textile web through a card machine. While the fiber web is placed on a conveyor and conveyed, a water flow is applied at a water pressure of 2 MPa, then inverted and a water flow is applied at a water pressure of 4 MPa, the fibers are pre-entangled with each other, and then the fibers are further inverted. A water flow was applied at a water pressure of 6 MPa to entangle the fibers with each other. Then, it was dried to obtain a nonwoven fabric having a basis weight of 62 g / m ^2.

Example 2
Instead of the polyester fiber, a polypropylene fiber having a fineness of 1.7 decitex and a fiber length of 44 mm (“Polypropylene PN” manufactured by Daiwabo Holdings Co., Ltd.) was used, and the basis weight was 72 g / m ^{2 by the same method as in Example 1.} Non-woven fabric was obtained. The official moisture content of polypropylene fiber is about 0.0%.

Example 3
^{By the same method as in Example 1, a basis weight of 69 g / m 2} was used, except that a polylactic acid fiber having a fineness of 1.7 decitex and a fiber length of 51 mm (“Teramac PL01” manufactured by Unitika Ltd.) was used instead of the polyester fiber. Non-woven fabric was obtained. The official moisture content of the polylactic acid fiber is about 0.5%.

Example 4
Instead of the crimped artificial protein short fiber 1, the crimped artificial protein short fiber 2 containing the modified fibroin 2 having the amino acid sequence of SEQ ID NO: 15 is used, and the meshing is 55 g by the same method as in Example 1. A non-woven fabric of / m ^{2 was obtained.}

Example 5
Instead of the polyester fiber, a polylactic acid fiber having a fineness of 1.7 decitex and a fiber length of 51 mm (“Teramac PL01” manufactured by Unitika Ltd.) was used, and the basis weight was 55 g / m ^{2 by the same method as in Example 4.} Non-woven fabric was obtained.

Comparative Example 1
A nonwoven fabric having ^{a basis weight of 64 g / m 2} was obtained by the same method as in Example 1 except that a fiber web made of only crimped artificial protein short fibers 1 was used without using polyester fibers.

Comparative Example 2
The same as in Example 1 except that polyacrylonitrile fiber (“Bonnel H129” manufactured by Mitsubishi Chemical Corporation), which is a hydrophilic synthetic fiber having a fineness of 1.0 decitex and a fiber length of 44 mm, was used instead of the polyester fiber. By the method, a non-woven fabric having a grain size of 57 g / m ^{2 was obtained.} The official moisture content of the polyacrylonitrile fiber is about 2.0%.

Comparative Example 3
Same as Example 1 except that rayon fiber (“Hope NWD” manufactured by Omikenshi Co., Ltd.), which is a hydrophilic synthetic fiber having a fineness of 1.7 decitex and a fiber length of 40 mm, was used instead of the artificial protein short fiber 1. A non-woven fabric having a grain size of 64 g / m ^{2 was obtained by the above method.} The official moisture content of rayon fiber is about 11.0%.

The following physical properties of the nonwoven fabrics obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were measured and found to be as shown in Table 4.
[Water absorption capacity]
The water absorption capacity (%) was measured according to JIS L 1912.
[Suction height]
According to JIS L 1912, the suction height (mm) after 1 minute in the MD direction (the direction in which the fiber web is conveyed) and the CD direction (the direction orthogonal to the MD direction) of the non-woven fabric. Was measured.

[Table 4]
━━━━━━━━━━━━━━━━━━━━━━━━━━━
Water absorption capacity ━━━━━━━━━━━━━━━━━━
MD direction CD direction ━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Example 1 1064 2 1
Example 2 603 6 1
Example 3 613 0 0
Example 4 491 0 0
Example 5 370 0 0
Comparative Example 1 505 47 54
Comparative Example 2 982 40 51
Comparative Example 3 1010 30 25
━━━━━━━━━━━━━━━━━━━━━━━━━━━

As can be seen from the results in Table 4, the nonwoven fabric according to the example has a lower suction height in both the MD direction and the CD direction than the nonwoven fabric according to the comparative example. This means that even if water is dropped on the nonwoven fabric according to the embodiment, the water does not diffuse in the plane direction. Therefore, if the non-woven fabric according to the example is used as a surface material of a sanitary material such as a sanitary napkin, the body fluid is well absorbed and permeated, but the body fluid does not diffuse in the surface direction, and the hygienic material that does not easily cause stickiness on the skin is provided. It can be done.

Claims

A non-woven fabric having a region formed by mixing artificial protein fibers containing artificial fibroin and hydrophobic synthetic fibers.
The non-woven fabric according to claim 1, wherein the artificial protein fiber containing artificial fibroin and the hydrophobic synthetic fiber are mixed in the entire region.
The non-woven fabric according to claim 1 or 2, wherein the artificial protein fiber containing artificial fibroin and the hydrophobic synthetic fiber are uniformly mixed.
The nonwoven fabric according to any one of claims 1 to 3, wherein the artificial fibroin is a modified spider silk fibroin.
The average hydropathy index of artificial fibroin is. The nonwoven fabric according to any one of claims 1 to 4, which is −1.0 or higher.
The non-woven fabric according to claim 5, wherein the average hydropathic index of artificial fibroin exceeds 0.0.
The nonwoven fabric according to any one of claims 1 to 6, which contains 10 to 90% by mass of artificial protein fibers.
The non-woven fabric according to any one of claims 1 to 7, wherein the official moisture content of the hydrophobic synthetic fiber is less than 2%.
The nonwoven fabric according to any one of claims 1 to 8, wherein the hydrophobic synthetic fiber is at least one fiber selected from the group consisting of polyethylene terephthalate fiber, polypropylene fiber and polylactic acid fiber.
A method for producing a non-woven fabric, which comprises a step of mixing an artificial protein fiber containing artificial fibroin and a hydrophobic synthetic fiber.
A claim for further promoting mixing by applying a water stream to a fiber web formed by mixing an artificial protein fiber containing artificial fibroin and a hydrophobic synthetic fiber and entwining the artificial protein fiber with the hydrophobic synthetic fiber. Item 10. The method for producing a nonwoven fabric according to Item 10.