WO2024090523A1

WO2024090523A1 - Lofty blended yarn and method for producing same

Info

Publication number: WO2024090523A1
Application number: PCT/JP2023/038721
Authority: WO
Inventors: 皓斗佐藤; 瑞季西門; 和秀関山; 憲児東; 嘉隆中川
Original assignee: Ｓｐｉｂｅｒ株式会社; 中川絹糸株式会社
Priority date: 2022-10-26
Filing date: 2023-10-26
Publication date: 2024-05-02

Abstract

The present invention relates to a lofty blended yarn containing: first fibers comprising engineered protein fibers that contain engineered proteins and that are shrinkable on contact with water; and second fibers having a lower shrinkage rate on contact with water than the first fibers. The loftiness of the blended yarn is 10 cm³/g or greater.

Description

Bulky blended yarn and its manufacturing method

The present invention relates to a bulky blended yarn and a method for producing the same.

Patent Document 1 discloses an acrylic fiber bulk processing device that performs bulk processing (bulkification processing) on acrylic fibers, and a manufacturing method thereof. Patent Document 2 discloses a knitted fabric made of high-shrinkage acrylic fibers with a boiling water shrinkage rate of 15% or more and a single fiber fineness of 0.7 to 2.2 dtex and low-shrinkage fibers with a boiling water shrinkage rate of 10% or less, and having a specific volume of 6 to 12 ^cm3 /g and a heat retention rate of 28 to 60%. Patent Document 2 describes that the knitted fabric has an excellent texture, a soft surface touch, excellent dimensional stability, and is lightweight, bulky, and excellent in heat retention.

JP 2003-328241 A JP 2014-101601 A

The object of the present invention is to provide a new bulky blended yarn using fibers containing artificial proteins, a manufacturing method thereof, and a new fabric using bulky blended yarn containing artificial protein fibers.

The present invention relates to, for example, the following inventions.
[1]
A bulky blended yarn comprising a first fiber containing an artificial protein and capable of shrinking upon contact with water, and a second fiber having a shrinkage rate upon contact with water lower than that of the first fiber, and having a bulkiness of 10 cm ³ /g or more.
[2]
The bulky blended yarn according to [1], wherein the bulkiness is 50 cm ³ /g or less.
[3]
The bulky blended yarn according to [1] or [2], wherein the first fiber has a shrinkage rate of 15% or more upon contact with water.
[4]
The bulky blended yarn according to any one of [1] to [3], wherein the number of crimps of the first fiber is 5 or more.
[5]
The bulky blended yarn according to any one of [1] to [4], wherein the content of the first fiber is 5 mass% or more based on the total mass of the bulky blended yarn.
[6]
The bulky blended yarn according to [5], wherein the content of the first fiber is 90 mass% or less, based on the total mass of the bulky blended yarn.
[7]
The bulky blended yarn according to any one of [1] to [6], wherein the average length of the first fibers is 48 mm or more and 170 mm or less.
[8]
The bulky blended yarn according to any one of [1] to [7], wherein the first fibers and the second fibers are different from each other.
[9]
The bulky blended yarn according to any one of [1] to [7], wherein the first fibers and the second fibers are of the same type.
[10]
The bulky blended yarn according to [8], wherein the second fiber is at least one of animal hair fiber and silk.
[11]
The bulky blended yarn according to [10], wherein the second fiber is animal hair fiber or silk.
[12]
The bulky blended yarn according to any one of [1] to [11], which is spun by woolen spinning.
[13]
A method for producing a bulky blended yarn, comprising: a step of blending a first sliver containing a first fiber that contains an artificial protein and is shrinkable upon contact with water with a second sliver containing a second fiber whose shrinkage rate upon contact with water is lower than that of the first fiber to obtain a raw blended yarn; and a step of contacting the raw blended yarn with an aqueous medium to shrink at least the first fiber to obtain a bulky blended yarn.
[14]
The method of claim 13, further comprising obtaining the first sliver.
[15]
The method according to [13] or [14], wherein the step of obtaining the blended yarn is carried out by worsted spinning.
[16]
A fabric comprising the bulky blended yarn according to any one of [1] to [12].

The present invention can provide a new bulky blended yarn containing fibers that contain artificial proteins and a manufacturing method thereof. It can also provide a new fabric using a bulky blended yarn that contains artificial protein fibers.

The bulky blended yarn of the present invention has excellent water absorption properties because it contains an artificial protein. In addition, since it contains a first fiber containing an artificial protein that can be molecularly designed, and a second fiber that is different from the first fiber, the bulky blended yarn of the present invention can ensure a wide variety of properties. Furthermore, since the fabric of the present invention also contains the bulky blended yarn as described above, it has excellent water absorption properties and can ensure a wide variety of properties.

FIG. 1 is an explanatory diagram illustrating an example of a spinning apparatus for producing a first fiber (artificial protein fiber).

Below, the form for implementing this disclosure will be described in detail, with reference to the drawings where appropriate. However, the following embodiments are merely examples for explaining this disclosure, and are not intended to limit this disclosure to the following content.

Unless otherwise specified, the materials exemplified in this specification may be used alone or in combination of two or more. When multiple substances corresponding to each component are present in the composition, the content of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified.

[Bulky blended yarn]
The bulky blended yarn of this embodiment includes a first fiber that contains an artificial protein and is shrinkable upon contact with water, and a second fiber that has a lower shrinkage rate upon contact with water than the first fiber.

The bulkiness of the bulky blended yarn is 10 cm ³ /g or more. The bulkiness of the bulky blended yarn may be 15 cm ³ /g or more, 20 cm ³ /g or more, 25 cm ³ /g or more, 30 cm ³ /g or more, 35 cm ³ /g or more, 40 cm ³ /g or more, 45 cm ³ /g or more, 50 cm ³ /g or more, or 55 cm ³ /g or more. The bulkiness of the bulky blended yarn may be 70 cm ³ /g or less, 65 cm ³ /g or less, 60 cm ³ /g or less, 55 cm ³ /g or less, 50 cm ³ /g or less, 45 cm ³ /g or less, or 40 cm ³ /g or less. The higher the bulkiness, the more improved the softness, heat retention, water absorbency, and anti-pilling properties of the bulky blended yarn.

The bulkiness of bulky blended yarn is measured in accordance with JIS L 1095A method.

The bulkiness of the bulky blended yarn can be adjusted, for example, by controlling the shrinkage rate of the first fiber upon contact with water and the shrinkage rate of the second fiber upon contact with water. The bulkiness tends to be increased, for example, by increasing the difference between the shrinkage rate of the first fiber upon contact with water and the shrinkage rate of the second fiber upon contact with water.

<First fiber>
The first fiber is a fiber containing an artificial protein (artificial protein fiber). The fiber containing an artificial protein referred to here includes a fiber containing only an artificial protein, a fiber containing a component other than the artificial protein that is not physically or chemically bonded to the artificial protein, or a fiber containing a component that is physically or chemically bonded to the artificial protein. In addition, the artificial protein includes a chemically modified artificial protein, an artificial protein derivative, etc.

(Artificial Proteins)
In this specification, the term "artificial protein" refers to a protein that is artificially produced. Artificial proteins include recombinant proteins and synthetic proteins. An artificial protein may be a protein whose domain sequence is different from the amino acid sequence of a naturally occurring protein, or may be a protein whose domain sequence is identical to the amino acid sequence of a naturally occurring protein. An "artificial protein" may be a protein that uses the amino acid sequence of a naturally occurring protein as is, may be a protein whose amino acid sequence has been modified based on the amino acid sequence of a naturally occurring protein (for example, 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 that has been artificially designed and synthesized without relying on a naturally occurring protein (for example, a protein having a desired amino acid sequence by chemically synthesizing a nucleic acid that codes for a designed amino acid sequence).

Unlike natural proteins, the amino acid sequence of artificial proteins can be freely designed, and therefore the functions, characteristics, physical properties, etc. of the first fiber containing an artificial protein and the bulky blended yarn containing the first fiber can be freely controlled by appropriately designing the amino acid sequence of the artificial protein. Since artificial proteins can always be designed with uniform molecular design, it is possible to stably obtain artificial proteins that are highly homologous to the target protein and are suited to the purpose. This advantageously stabilizes the quality of the first fiber containing an artificial protein and the bulky blended yarn containing the first fiber. From this point of view, artificial structural proteins are advantageously used as the artificial protein.

The number of amino acid residues in the artificial protein is not particularly limited, but may be, for example, 50 or more. The number of amino acid residues may be, for example, 100 or more, 150 or more, 200 or more, 250 or more, 300 or more, 350 or more, 400 or more, 450 or more, or 500 or more. The number of amino acid residues may be, for example, 5000 or less, 4500 or less, 4000 or less, 3500 or less, 3000 or less, 2500 or less, 2000 or less, 1500 or less, or 1000 or less. The fewer the number of amino acid residues, the higher the solubility in a solvent tends to be.

The molecular weight of the artificial protein is not particularly limited, but may be, for example, 2 kDa or more and 500 kDa or less. The molecular weight of the artificial protein may be, for example, 2 kDa or more, 3 kDa or more, 4 kDa or more, 5 kDa or more, 6 kDa or more, 7 kDa or more, 8 kDa or more, 9 kDa or more, 10 kDa or more, 20 kDa or more, 30 kDa or more, 40 kDa or more, 50 kDa or more, 60 kDa or more, 70 kDa or more, 80 kDa or more, 90 kDa or more, or 100 kDa or more, and may be 500 kDa or less, 400 kDa or less, less than 360 kDa, 300 kDa or less, or 200 kDa or less.

As an artificial protein, for example, an artificial protein having physical properties close to those required for a desired application can be used. An example of an artificial protein is an artificial protein that can be used for industrial purposes. "Usable for industrial purposes" means that it can be used for various general-purpose materials used indoors and/or outdoors. An example of an artificial protein that can be used for industrial purposes is an artificial structural protein.

<Artificial structural proteins>
The artificial protein may be, for example, an artificial structural protein. In this specification, the term "artificial structural protein" refers to an artificially produced structural protein. A structural protein is a type of artificial protein that can be used for industrial purposes, and refers to a protein involved in the structure of a living organism, a protein that constitutes a structure produced by a living organism, or a protein derived therefrom. A structural protein also refers to a protein that self-aggregates under certain conditions to form a structure such as a fiber, a film, a resin, a gel, a micelle, or a nanoparticle. Furthermore, a structural protein can also be said to be a protein that has repeated motifs consisting of a characteristic amino acid sequence or a certain number of amino acid residues and forms the skeleton of an organism or material.

An artificial structural protein may be a structural protein produced from a microorganism using recombinant gene technology, and may have the same amino acid sequence as a natural structural protein, or may have an amino acid sequence that has been improved from the standpoint of productivity, moldability, etc.

Specific examples of artificial structural proteins include spider silk, silkworm silk, keratin, collagen, elastin, and resilin, as well as proteins derived from these.

The artificial structural protein according to this embodiment may have 150 or more amino acid residues. The number of amino acid residues may be, for example, 200 or more or 250 or more, and is preferably 300 or more, 350 or more, 400 or more, 450 or more, or 500 or more.

When forming an artificial structural protein, amino acids with relatively small side chains tend to form hydrogen bonds more easily and have higher strength. To provide superior strength, the alanine residue content may be, for example, 10-40%, 12-40%, 15-40%, 18-40%, 20-40%, or 22-40%. To provide superior strength, the glycine residue content may be, for example, 10-55%, 11-55%, 13-55%, 15-55%, 18-55%, 20-55%, 22-55%, or 25-55%.

As used herein, the "alanine residue content" refers to the number of alanine residues relative to the total number of amino acid residues constituting a protein, and is a value represented by the following formula:
Alanine residue content = (number of alanine residues contained in protein/total number of amino acid residues in protein) x 100 (%)

The glycine residue content, and the serine residue content, threonine residue content, proline residue content and tyrosine residue content described below are synonymous with the above formula, in which the alanine residue is replaced with glycine residue, serine residue, threonine residue, proline residue and tyrosine residue, respectively.

The artificial structural protein may have a total content (total content) of at least one amino acid residue selected from the group consisting of serine, threonine, and tyrosine (i.e., any of the serine residue content, the threonine residue content, the tyrosine residue content, the sum of the serine residue content and the threonine residue content, the sum of the serine residue content and the tyrosine residue content, the sum of the threonine residue content and the tyrosine residue content, the sum of the serine residue content, the threonine residue content and the tyrosine residue content), the alanine residue content, and the glycine residue content, based on the number of amino acid residues, of 40% or more. The total content may be, for example, 45% or more, 50% or more, 55% or more, or 60% or more. There is no particular upper limit to the total content, but it may be, for example, 90% or less, 85% or less, or 80% or less.

In one embodiment, the artificial structural protein may have a total content of serine residues, threonine residues, and tyrosine residues, based on the number of amino acid residues, of 4% or more, 4.5% or more, 5% or more, 5.5% or more, 6% or more, 6.5% or more, or 7% or more. The total content of serine residues, threonine residues, and tyrosine residues may be, for example, 35% or less, 33% or less, 30% or less, 25% or less, or 20% or less.

The artificial structural protein according to this embodiment has an average distribution of serine, threonine, or tyrosine residues, and the total content of serine, threonine, and tyrosine residues in any 20 consecutive amino acid residues may be 4% or more, 5% or more, 10% or more, or 15% or more, and may be 50% or less, 40% or less, 30% or less, or 20% or less.

Also, it is preferable that the artificial structural protein contains amino acids with relatively large side chains or amino acids with flexibility homogeneously to a certain extent throughout the entire sequence. Specifically, the artificial structural protein may contain a motif containing tyrosine residues, threonine residues, and proline residues in a repeated cycle. Such an artificial structural protein is likely to inhibit the formation of strong intermolecular hydrogen bonds during processing after molding, and is likely to improve processability. For example, the total content of proline residues, threonine residues, and tyrosine residues in any 20 consecutive amino acid residues may be 5% or more, more than 5.5%, 6.0% or more, more than 6.5%, 7.0% or more, more than 7.5%, 8.0% or more, more than 8.5%, 9.0% or more, 10.0% or more, or 15.0% or more. For example, the total content of proline residues, threonine residues, and tyrosine residues in any 20 consecutive amino acid residues may be 50% or less, 40% or less, 30% or less, or 20% or less.

The artificial structural protein may have a repetitive sequence. That is, the artificial structural protein may have multiple amino acid sequences (repetitive sequence units) with high sequence identity within the artificial structural protein. The number of amino acid residues in the repetitive sequence unit is preferably 6 to 200. The total number of glycine residues, serine residues, glutamine residues, and alanine residues relative to the total number of amino acid residues in the repetitive sequence unit may be 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, or 70% or more. Furthermore, the sequence identity between the repetitive sequence units may be, for example, 85% or more, 90% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more.

The hydrophobicity index of the repeating sequence unit may be, for example, -0.80 or more, -0.70 or more, -0.60 or more, -0.50 or more, -0.40 or more, -0.30 or more, -0.20 or more, -0.10 or more, 0.00 or more, 0.22 or more, 0.25 or more, 0.30 or more, 0.35 or more, 0.40 or more, 0.45 or more, 0.50 or more, 0.55 or more, 0.60 or more, 0.65 or more, or 0.70 or more. The upper limit of the hydrophobicity index of the repeating sequence unit is not particularly limited, but may be, for example, 1.0 or less, or 0.7 or less.

The hydropathic index is determined according to a known method using the known hydrophobicity index of amino acid residues. The known hydrophobicity index of amino acid residues is shown in Table 1. For example, the hydrophobicity may be calculated according to the method described in Kyte J, Doolittle R (1982) "A simple method for displaying the hydropathic character of a protein", J. Mol. Biol., 157, pp. 105-132.

The artificial structural protein may include an (A) _n motif. In the present specification, the (A) _n motif means an amino acid sequence mainly composed of alanine residues. The number of amino acid residues in the (A) _n motif may be 2 to 27, and may be an integer of 2 to 20, 2 to 16, or 2 to 12. The ratio of the number of alanine residues to the total number of amino acid residues in the (A) _n motif may be 40% or more, 60% or more, 70% or more, 80% or more, 83% or more, 85% or more, 86% or more, 90% or more, 95% or more, or 100%. The ratio of the number of alanine residues to the total number of amino acid residues in the (A) _n motif being 100% means that the (A) _n motif is composed of only alanine residues.

The (A) _n motif may be such that the total number of alanine residues, serine residues, threonine residues and valine residues relative to the total number of amino acid residues in the (A) _n motif is 80% or more, preferably 85% or more, more preferably 90% or more, even more preferably 95% or more, and even more preferably 100% (meaning that it is composed of only one or more amino acid residues selected from alanine residues, serine residues, threonine residues and valine residues). The (A) _n motifs present in the recombinant structural protein according to this embodiment may have the same amino acid sequence or different amino acid sequences. In addition, since the (A) _n motif mainly contains alanine residues, it is likely to have an α-helix structure or a β-sheet structure. Since the (A) _n motif is included in the repeating sequence unit, the artificial structural protein according to this embodiment will have these secondary structures repeatedly, and as described below, when the artificial structural protein is made into a fiber form, it is expected that these secondary structures will provide high strength.

The artificial structural protein may be an artificial fibroin. In this specification, "artificial fibroin" means artificially produced fibroin (man-made fibroin). The artificial fibroin may be a fibroin having an amino acid sequence different from that of naturally occurring fibroin, or may be a fibroin having an amino acid sequence identical to that of naturally occurring fibroin.

Examples of naturally occurring fibroin include fibroin produced by insects or spiders. Natural fibroin is a fibrous protein with a molecular weight of approximately 370,000, composed of two subunits, and has a high content of glycine, alanine, serine and tyrosine residues, with these amino acid residues accounting for nearly 90% of the total number of amino acid residues. Natural fibroin has crystalline regions rich in amino acid residues with relatively small side chains such as glycine, alanine and serine, and amorphous regions with amino acid residues with relatively large side chains such as tyrosine.

A more specific example of naturally derived fibroin is a fibroin whose sequence information is registered in NCBI GenBank. For example, it can be confirmed by extracting from among the sequences registered in NCBI GenBank that contain INV as a division, sequences with spidroin, amplify, fibroin, "silk and polypeptide", or "silk and protein" as keywords in DEFINITION, a specific product character string from CDS, and a specific character string in TISSUE TYPE from SOURCE.

Artificial fibroin can be produced by known methods, for example, the method described in WO 2019/194263.

Artificial fibroin may be a fibrous protein having a structure similar to that of naturally occurring fibroin, or may be a fibroin having a sequence similar to the repetitive sequence of naturally occurring fibroin. "A sequence similar to the repetitive sequence of fibroin" may be an actual sequence found in naturally occurring fibroin, or a sequence similar thereto.

As long as the artificial fibroin has an amino acid sequence specified in this disclosure, it may be one in which the amino acid sequence is modified based on naturally occurring fibroin (for example, one in which the amino acid sequence is modified by modifying the genetic sequence of a cloned naturally occurring fibroin), or it may be one in which the amino acid sequence is artificially designed without relying on naturally occurring fibroin (for example, one in which the desired amino acid sequence is obtained by chemically synthesizing a nucleic acid that codes for a designed amino acid sequence). Artificial fibroins with modified amino acid sequences are also included in the artificial fibroin category, so long as the amino acid sequence differs from that of naturally occurring fibroin.

Examples of artificial fibroins include artificial silk fibroin (a silk protein produced by silkworms with a modified amino acid sequence) and artificial spider silk fibroin (a spider silk protein produced by spiders with a modified amino acid sequence). Since the artificial fibroin is relatively easy to fibrillate and has a high fiber forming ability, it preferably contains artificial spider silk fibroin, and more preferably consists of artificial spider silk fibroin.

The artificial fibroin may be a protein containing a domain sequence represented by formula 1: [(A) _n motif-REP] _m , or formula 2: [(A) _n motif-REP] _m- (A) _n motif. The artificial fibroin may further have amino acid sequences (N-terminal sequence and C-terminal sequence) added to either or both of the N-terminal side and C-terminal side of the domain sequence. The N-terminal sequence and the C-terminal sequence are typically, but are not limited to, regions that do not have repetitions of amino acid motifs characteristic of fibroin and consist of about 100 amino acid residues.

As used herein, the term "domain sequence" refers to an amino acid sequence represented by formula 1: [(A) _n motif-REP] _m , or formula 2: [(A) _n motif-REP] _m- (A) _n motif. Here, the (A) _n motif indicates an amino acid sequence mainly composed of alanine residues, and has 2 to 27 amino acid residues. The number of amino acid residues in the (A) _n motif may be an integer of 2 to 20, 4 to 27, 4 to 20, 8 to 20, 10 to 20, 4 to 16, 8 to 16, or 10 to 16. In addition, the ratio of the number of alanine residues to the total number of amino acid residues in the (A) _n motif may be 40% or more, and may be 60% or more, 70% or more, 80% or more, 83% or more, 85% or more, 86% or more, 90% or more, 95% or more, or 100% (meaning that the sequence is composed only of alanine residues). At least seven of the (A) _n motifs present in the domain sequence may be composed of only alanine residues. REP represents an amino acid sequence composed of 2 to 200 amino acid residues. REP may be an amino acid sequence composed of 10 to 200 amino acid residues. m represents an integer of 2 to 300, and may be an integer of 10 to 300. The (A) _n motifs present in the domain sequence may be the same amino acid sequence as each other, or different amino acid sequences. The REPs present in the domain sequence may be the same amino acid sequence as each other, or different amino acid sequences.

Specific examples of artificial fibroins include artificial fibroins derived from the large spinal duct dragline silk protein produced in the large ampullate gland of spiders as described in WO 2021/187502 (first artificial fibroin), artificial fibroins having a domain sequence with a reduced content of glycine residues (second artificial fibroin), artificial fibroins having a domain sequence with a reduced content of (A) _n motifs (third artificial fibroin), artificial fibroins having a reduced content of glycine residues and (A) _n motifs (fourth artificial fibroin), artificial fibroins having a domain sequence including a region with a locally high hydrophobic index (fifth artificial fibroin), and artificial fibroins having a domain sequence with a reduced content of glutamine residues (sixth artificial fibroin). The definitions of the first to sixth artificial fibroins are incorporated herein by reference in the contents of WO 2021/187502.

The artificial fibroin may contain a tag sequence at either or both of the N-terminus and C-terminus. This allows the artificial fibroin to be isolated, immobilized, detected, and visualized. PRT966 is the sixth artificial fibroin that contains a tag sequence.

An example of a tag sequence is an affinity tag that utilizes specific affinity (binding ability, affinity) with other molecules. A specific example of an affinity tag is a histidine tag (His tag). A His tag is a short peptide with a sequence of about 4 to 10 histidine residues, and has the property of specifically binding to metal ions such as nickel, so it can be used to isolate artificial fibroin by chelating metal chromatography. A specific example of a tag sequence is the amino acid sequence shown in SEQ ID NO: 8 (an amino acid sequence including a His tag sequence and a hinge sequence).

It is also possible to use tag sequences such as glutathione-S-transferase (GST), which specifically binds to glutathione, and maltose-binding protein (MBP), which specifically binds to maltose.

Furthermore, it is also possible to use "epitope tags" that utilize antigen-antibody reactions. By adding an antigenic peptide (epitope) as a tag sequence, it is possible to bind an antibody against the epitope. Examples of epitope tags include HA tags (peptide sequence of influenza virus hemagglutinin), myc tags, and FLAG tags. By using epitope tags, artificial fibroin can be easily purified with high specificity.

Furthermore, a tag sequence that can be cleaved with a specific protease can also be used. By treating the protein adsorbed via the tag sequence with a protease, it is possible to recover the artificial fibroin from which the tag sequence has been cleaved.

Specific examples of artificial fibroins include those shown in SEQ ID NOs: 1 to 7. The artificial fibroins may be artificial fibroins shown in SEQ ID NOs: 1 to 7 or artificial fibroins containing amino acid sequences having 90% or more sequence identity with these amino acid sequences. The contents of alanine residues, glycine residues, serine residues, threonine residues, proline residues and tyrosine residues in the artificial fibroins shown in SEQ ID NOs: 1 to 7 are shown in Table 2 below.

The artificial fibroin may be an artificial fibroin having at least two or more characteristics of the first artificial fibroin, the second artificial fibroin, the third artificial fibroin, the fourth artificial fibroin, the fifth artificial fibroin, and the sixth artificial fibroin.

The molecular weight of the artificial fibroin according to this embodiment is not particularly limited, and may be, for example, 2 kDa or more and 700 kDa or less. The molecular weight of the artificial fibroin may be, for example, 2 kDa or more, 3 kDa or more, 4 kDa or more, 5 kDa or more, 6 kDa or more, 7 kDa or more, 8 kDa or more, 9 kDa or more, 10 kDa or more, 20 kDa or more, 30 kDa or more, 40 kDa or more, 50 kDa or more, 60 kDa or more, 70 kDa or more, 80 kDa or more, 90 kDa or more, or 100 kDa or more, and may be 700 kDa or less, 600 kDa or less, 500 kDa or less, 400 kDa or less, less than 360 kDa, 300 kDa or less, or 200 kDa or less.

(Artificial protein content)
The content of the artificial protein may be 30% by mass or more, 40% by mass or more, or 50% by mass or more, 60% by mass or more, 70% by mass or more, or 80% by mass or more, and 100% by mass or less, 95% by mass or less, or 90% by mass or less, based on the total mass of the first fiber. The higher the protein content, the higher the shrinkage rate of the first fiber due to contact with water tends to be. The range of the artificial protein content combining the above upper limit value and lower limit value includes any range (e.g., 30 to 100% by mass, 40 to 95% by mass, etc.) determined by arbitrarily selecting the above upper limit value and lower limit value, respectively.

(Shrinkage due to contact with water)
The first fiber is a fiber that can shrink when contacted with water. The shrinkage rate of the first fiber when contacted with water may be, for example, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, or 50% or more. The shrinkage rate of the first fiber when contacted with water may be, for example, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, or 55% or less. The higher the shrinkage rate of the first fiber when contacted with water, the more the bulkiness of the blended yarn is improved, and thus the flexibility, heat retention, pilling properties, water absorbency, and anti-pilling properties of the bulky blended yarn are improved. The range of the shrinkage percentage of the first fiber due to contact with water, which is a combination of the above-mentioned upper limit value and lower limit value, includes any range determined by arbitrarily selecting the above-mentioned upper limit value and lower limit value, respectively (e.g., 10 to 80%, 15 to 80%, 20 to 75%, etc.).

The "shrinkage rate due to contact with water" in this specification can be measured by the following method. First, a plurality of fibers having the same length are bundled to obtain a fiber bundle, and a 0.8 g lead weight is attached to this fiber bundle and it is immersed in water at 95°C for 10 minutes. After that, the fiber bundle is taken out of the water, and the fiber bundle is dried at room temperature for 2 hours with the 0.8 g lead weight still attached, and the length of the fiber bundle after drying is measured. Next, the "shrinkage rate due to contact with water (%)" of the fiber is calculated according to the following formula I. In formula I, L0 indicates the length of the fiber bundle before contact with water, and Ld indicates the length of the fiber bundle after shrinking due to contact with water and being in a dry state.
Formula I: Shrinkage rate = {1 - (Ld/L0)} x 100 (%)

The "shrinkage rate upon contact with water" in this specification can be adjusted by controlling the amino acid sequence of the artificial protein and the manufacturing conditions of the fiber (for example, the stretching conditions, if a stretching process is performed during fiber manufacturing).

(Number of crimps)
The number of crimps of the first fiber may be, for example, 5 or more, 7 or more, 9 or more, 11 or more, 13 or more, 15 or more, or 16 or more. The number of crimps of the first fiber may be, for example, 20 or less, 19 or less, 18 or less, or 17 or less. The higher the first crimp number, the more the bulkiness of the blended yarn improves, and the bulky blended yarn tends to have higher flexibility, heat retention, pilling resistance, water absorbency, and anti-pilling properties. The range of the number of crimps of the first fiber, which is a combination of the above upper limit and lower limit, includes any range (e.g., 5 to 20, 7 to 18, etc.) determined by arbitrarily selecting the above upper limit and lower limit, respectively.

The number of crimps can be measured in accordance with JIS L 1015.

The crimping of the first fiber occurs mainly due to shrinkage of the blended yarn upon contact with water, as described below. Therefore, the number of crimps of the first fiber, like the "shrinkage rate upon contact with water" of the first fiber, can be adjusted by controlling the amino acid sequence of the artificial protein and the manufacturing conditions of the fiber (for example, the stretching conditions, etc., if a stretching process is performed during the manufacturing of the fiber).

(Average length of first fiber)
The average length of the first fibers may be, for example, 48 mm or more, 50 mm or more, 60 mm or more, 70 mm or more, 80 mm or more, 90 mm or more, 100 mm or more, 110 mm or more, 120 mm or more, 130 mm or more, 140 mm or more, or 150 mm or more, and may be 170 mm or less, or 160 mm or less. Note that, as the first average length is higher, the bulkiness of the blended yarn is improved, and the flexibility, heat retention, pilling properties, water absorbency, and anti-pilling properties of the bulky blended yarn tend to be improved. The range of the average length of the first fibers, which is a combination of the above upper limit value and lower limit value, includes any range (e.g., 48 to 170 mm, 70 to 160 mm, etc.) determined by arbitrarily selecting the above upper limit value and lower limit value, respectively.

In this specification, "average fiber length" refers to the length of short fibers randomly extracted from the bulky blended yarn. Specifically, "average fiber length" is measured in accordance with JIS L 1015C method.

(Fineness of First Fiber)
The fineness of the first fiber may be, for example, 0.5 denier or more, 0.7 denier or more, 1.0 denier or more, 1.5 denier or more, or 2.0 denier or more. The fineness of the first fiber may be, for example, 5 denier or less, 4.5 denier or less, 4.0 denier or less, or 3.5 denier or less. For example, by controlling the molecular design of the artificial protein contained in the first fiber, it is possible to realize a fiber with excellent mechanical strength even if it is low in fineness, and a fiber with excellent flexibility even if it is high in fineness. The range of the fineness of the first fiber, which is a combination of the above upper limit value and the lower limit value, includes any range (for example, 1.0 to 3.5 denier, etc.) determined by arbitrarily selecting the above upper limit value and the lower limit value, respectively.

(Content of First Fiber)
The content of the first fiber may be, for example, 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, 40% by mass or more, 45% by mass or more, 50% by mass or more, 55% by mass or more, 60% by mass or more, 65% by mass or more, 70% by mass or more, 75% by mass or more, or 80% by mass or more, and 90% by mass or less, or 85% by mass or less, based on the total mass of the bulky blended yarn. If the content of the first fiber is too low, the bulkiness of the bulky blended yarn may be reduced. The range of the content of the first fiber, which is a combination of the above upper limit value and the lower limit value, includes any range (for example, 5 to 90%, 10 to 85%, etc.) determined by arbitrarily selecting the above upper limit value and lower limit value, respectively. In addition, the content of the first fiber can be appropriately determined depending on the difference between the shrinkage rate of the first fiber upon contact with water and the shrinkage rate of the second fiber upon contact with water, or depending on the desired characteristics of the bulky blended yarn to be achieved by combining the characteristics of the first fiber and the characteristics of the second fiber.

(Method of Manufacturing First Fiber)
The first fiber can be produced by a conventional spinning method, including the steps of obtaining a dope solution containing an artificial protein and spinning the dope solution to obtain the first fiber containing the artificial protein.

The dope solution can be obtained by dissolving the artificial protein in a solvent. Examples of the solvent include dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), and hexafluoroisopronol (HFIP). A dissolution promoter may be used as necessary to dissolve the artificial protein. Examples of the dissolution promoter include inorganic salts.

Spinning methods include wet spinning, dry spinning, dry-wet spinning, melt spinning, etc. Preferred spinning methods include wet spinning and dry-wet spinning.

FIG. 1 is an explanatory diagram that shows a schematic diagram of an example of a spinning apparatus for producing a first fiber. The spinning apparatus 10 shown in FIG. 1 is an example of a spinning apparatus for dry/wet spinning, and includes an extrusion device 1, an undrawn yarn production device 2, a wet heat drawing device 3, and a drying device 4.

A spinning method using a spinning device 10 will be described. First, the dope liquid 6 stored in the storage tank 7 is extruded from the nozzle 9 by the gear pump 8. In a laboratory scale, the dope liquid may be filled in a cylinder and extruded from a nozzle using a syringe pump. Next, the extruded dope liquid 6 is supplied to the coagulation liquid 11 in the coagulation liquid tank 20 through the air gap 19, the solvent is removed, the artificial protein is coagulated, and a fibrous coagulate is formed. Next, the fibrous coagulate is supplied to the warm water 12 in the drawing bath 21 and drawn. The drawing ratio is determined by the speed ratio between the supply nip roller 13 and the take-up nip roller 14. Thereafter, the drawn fibrous coagulate is supplied to the drying device 4 and dried in the yarn path 22, and the artificial protein fiber 36 is obtained as a wound yarn body 5. 18a to 18g are yarn guides.

The coagulation liquid 11 may be any solvent capable of desolvation, such as lower alcohols having 1 to 5 carbon atoms, such as methanol, ethanol, and 2-propanol, and acetone. The coagulation liquid 11 may contain water as appropriate. The temperature of the coagulation liquid 11 is preferably 0 to 30°C. When a syringe pump having a nozzle with a diameter of 0.1 to 0.6 mm is used as the nozzle 9, the extrusion speed is preferably 0.2 to 6.0 ml/hour per hole, and more preferably 1.4 to 4.0 ml/hour. The distance over which the coagulated protein passes through the coagulation liquid 11 (effectively the distance from the thread guide 18a to the thread guide 18b) may be a length that allows efficient desolvation, and is, for example, 200 to 500 mm. The take-up speed of the undrawn thread may be, for example, 1 to 20 m/min, and is preferably 1 to 3 m/min. The residence time in the coagulation liquid 11 may be, for example, 0.01 to 3 minutes, and preferably 0.05 to 0.15 minutes. Also, stretching (pre-stretching) may be performed in the coagulation liquid 11. The coagulation liquid tank 20 may be provided in multiple stages, and stretching may be performed in each stage or in a specific stage as necessary.

The stretching performed to obtain the first fiber may be, for example, the pre-stretching performed in the coagulation liquid bath 20 described above, the wet heat stretching performed in the stretching bath 21, or dry heat stretching.

The wet heat drawing can be carried out in hot water, in a solution of hot water with an organic solvent added, or under steam heating. The temperature may be, for example, 50 to 90°C, with 75 to 85°C being preferred. In the wet heat drawing, the undrawn yarn (or pre-drawn yarn) can be drawn, for example, 1 to 10 times, with 2 to 8 times being preferred.

Dry heat drawing can be carried out using an electric tubular furnace or a dry heat plate. The temperature may be, for example, 140°C to 270°C, with 160°C to 230°C being preferred. In dry heat drawing, the undrawn yarn (or pre-drawn yarn) can be drawn, for example, 0.5 to 8 times, with 1 to 4 times being preferred.

　Wet heat stretching and dry heat stretching may be performed alone, or they may be performed in multiple stages or in combination. That is, wet heat stretching may be performed in the first stage and dry heat stretching in the second stage, or wet heat stretching may be performed in the first stage, wet heat stretching in the second stage, and dry heat stretching in the third stage, etc., and wet heat stretching and dry heat stretching may be performed in an appropriate combination.

The lower limit of the final draw ratio is preferably more than 1, 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, or 9 or more relative to the undrawn yarn (or pre-drawn yarn), and the upper limit is preferably 40 or less, 30 or less, 20 or less, 15 or less, 14 or less, 13 or less, 12 or less, 11 or less, or 10 or less relative to the undrawn yarn (or pre-drawn yarn). If the first fiber is a fiber spun at a draw ratio of 2 or more, the shrinkage rate of the first fiber due to contact with water tends to be higher.

<Second Fiber>
The second fiber is a fiber having a shrinkage rate lower than that of the first fiber when contacted with water. The second fiber may include at least one selected from the group consisting of synthetic fibers (including chemical fibers and semi-synthetic fibers), natural fibers, regenerated fibers, and artificial protein fibers. Examples of the second fiber include animal hair fibers such as wool, cashmere, mohair, angora, and alpaca, natural cellulose fibers such as silk (including regenerated silk), cotton, and hemp, regenerated cellulose fibers such as lyocell and rayon, artificial protein fibers, and synthetic fibers such as nylon fibers, polyester fibers, and acrylic fibers. Among the synthetic fibers, natural fibers, regenerated fibers, and artificial protein fibers, fibers having a shrinkage rate lower than that of the first fiber when contacted with water are selected. In addition, when the second fiber is an artificial protein fiber, an artificial protein fiber containing the same type of artificial protein as the artificial protein contained in the first fiber but having a shrinkage rate lower than that of the first fiber when contacted with water is selected as the second fiber, and an artificial protein fiber containing a type of artificial protein different from that of the artificial protein contained in the first fiber is selected.

(Shrinkage upon contact with water)
The shrinkage rate of the second fiber upon contact with water may be, for example, 0% or more, 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, or 30% or more. The shrinkage rate of the second fiber upon contact with water may be, for example, 45% or less, or 40% or less. The second fiber may be a fiber that does not shrink at all upon contact with water. The range of the shrinkage rate of the second fiber upon contact with water, which is a combination of the above upper limit value and lower limit value, includes any range (e.g., 0 to 45% and 5 to 40%) determined by arbitrarily selecting the above upper limit value and lower limit value, respectively.

The difference (X1-X2) between the shrinkage rate X1 of the first fiber due to contact with water and the shrinkage rate X2 of the second fiber due to contact with water may be, for example, 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, or 40% or more, and may be 50% or less, or 45% or less. The larger the difference (X1-X2) between the shrinkage rate X1 and the shrinkage rate X2, the more the bulkiness of the blended yarn improves, and the softness, heat retention, pilling resistance, water absorption, and anti-pilling properties of the bulky blended yarn tend to increase. The range of the difference (X1-X2) between the shrinkage rate X1 and the shrinkage rate X2, which is a combination of the upper and lower limits described above, includes any range (e.g., 5 to 50% and 10 to 45%, etc.) determined by arbitrarily selecting the upper and lower limits described above.

(Number of crimps)
The number of crimps of the second fiber may be, for example, 5 or more, 7 or more, 9 or more, 11 or more, 13 or more, 15 or more, 17 or more, 19 or more, or 20 or more. The number of crimps of the second fiber may be, for example, 25 or less, 23 or less, or 21 or less. The range of the number of crimps of the second fiber, which is a combination of the above upper limit and lower limit, includes any range determined by arbitrarily selecting the above upper limit and lower limit, respectively (for example, 5 to 25, 7 to 23, etc.).

(Average length of second fiber)
The average length of the second fibers may be, for example, 48 mm or more, 50 mm or more, 60 mm or more, 70 mm or more, 80 mm or more, 90 mm or more, 100 mm or more, 110 mm or more, 120 mm or more, 130 mm or more, 140 mm or more, 150 mm or more, or 160 mm or more, and may be 200 mm or less, 190 mm or less, 180 mm or less, or 170 mm or less. Note that the range of the average length of the second fibers, which is a combination of the above upper and lower limits, includes any range (e.g., 48 to 200 mm, 60 to 190 mm, etc.) determined by arbitrarily selecting the above upper and lower limits, respectively.

(Content of second fiber)
The content of the second fiber may be 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, or 50% by mass or more, and may be 95% by mass or less, 90% by mass or less, 80% by mass or less, 70% by mass or less, or 60% by mass or less, based on the total mass of the bulky blended yarn. The range of the content of the second fiber, which is a combination of the above upper limit value and lower limit value, includes any range (e.g., 5 to 50%, 10 to 45%, etc.) determined by arbitrarily selecting each of the above upper limit value and lower limit value.

(Method of obtaining the second fiber)
The second fiber may be a commercially available product as is, may be produced by a known general method, or may be produced by spinning using the same method as the first fiber.

<Applications>
The bulky blended yarn can be used, for example, in fabrics for clothing, bedding, and the like.

[Method for producing bulky blended yarn]
The method for producing the bulky blended yarn according to the present embodiment includes a step of blending a first sliver containing an artificial protein and a first fiber that can shrink when contacted with water with a second sliver containing a second fiber whose shrinkage rate when contacted with water is lower than that of the first fiber to obtain a raw blended yarn (blending step), and a step of contacting the raw blended yarn with water to shrink at least the first fiber to obtain a bulky blended yarn (shrinking step). This method can suitably produce the above-mentioned bulky blended yarn. Details of the artificial protein, the first fiber, and the second fiber may be as described above. According to this production method, it is possible to produce a bulky blended yarn having the above-mentioned bulkiness. In addition, as the spinning method used to obtain the raw blended yarn, for example, known spinning methods such as worsted spinning (including 2-inch spinning), woolen spinning, cotton spinning, and silk spinning can be adopted. From the viewpoint of obtaining a bulky blended yarn having a higher bulkiness, among these spinning methods, for example, worsted spinning can be advantageously adopted. The reason why a bulky blended yarn having a higher bulkiness can be obtained by using a raw spun yarn obtained by worsted spinning is considered to be as follows. The blended yarn obtained by worsted spinning has a smaller number of twists than blended yarns obtained by other spinning methods, so that the whole blended yarn becomes soft. It is considered that this increases the bulkiness effect obtained by the first water shrinkage. In addition, in worsted spinning, the fiber length of the staple used is longer than that of the staple used in woolen spinning and cotton spinning (for example, fibers with a length of 50 to 170 mm are used in worsted spinning), so the force required for drafting when aligning the slivers is larger. Therefore, in worsted spinning, a larger residual stress is generated in the first fiber, and the shrinkage rate due to contact with water is larger. As a result, it is believed that the bulky blended yarn has a higher bulkiness. In addition, in worsted spinning, when the sliver is drawn together, a comb-like body is used to comb the sliver, and this combing process exerts a large resistance on the fibers. This also generates a larger residual stress in the first fibers, and it is believed that the final bulky blended yarn has a higher bulkiness.

The first sliver may be one that has been prepared in advance (already made), or one that has been obtained by a process of making the first sliver using a tow that contains the first fiber (first sliver obtaining process). The second sliver may also be one that has been prepared in advance (already made), or one that has been obtained by a process of making the second sliver using a known method using the second fiber (second sliver obtaining process).

The first sliver obtaining process can be carried out, for example, by supplying a tow of the first fiber between two sets of rollers, one before and one after, and draft-cutting (stretch-cutting) the tow by making the surface speed of the latter roller faster than that of the former roller, i.e., by stretch-cutting the tow, a conventional method of obtaining the first sliver can be used.

By adopting a method of draft cutting a tow containing the first fiber in the first sliver obtaining process, the first sliver can be obtained with the first fiber in an unshrunk and uncrimped state. This makes it easier to obtain a bulky blended yarn whose bulkiness is within the above-mentioned range. In addition, when the tow is draft cut, the first fiber is pulled, which further increases the residual stress. This is thought to further increase the water shrinkage rate (shrinkage rate when in contact with water) of the first fiber. It is expected that this will result in a bulky blended yarn with sufficient bulkiness.

In the blending process, the first sliver and the second sliver are blended to obtain a raw blended yarn. The second sliver contains a second fiber. A commercially available product can be used as is for the second sliver, or the second sliver may be produced using a second fiber that has a lower shrinkage rate upon contact with water than the first fiber. Any known method can be used to obtain the second sliver using the second fiber.

The first sliver and the second sliver can be blended using a normal method for blending slivers. Blending can be performed, for example, by a method including a step of forming a roving from the first sliver and the second sliver, and a step of twisting the roving while applying a draft, with the aim of increasing the parallelism of the fibers and mixing them uniformly. Drafting in such a twisting process also further increases the residual stress of the first fiber, further improving the water shrinkage rate. As a result, it is expected that a bulky blended yarn with more sufficient bulkiness can be obtained.

By adopting the above-mentioned blending process, in addition to bulkiness, there is a tendency for elongation, heat retention, water absorption and anti-pilling properties to be improved.

In the shrinkage process, the raw blended yarn is brought into contact with an aqueous medium to shrink at least the first fiber to obtain a bulky blended yarn.

An aqueous medium is a liquid or gas (steam) medium that contains water (including water vapor). The aqueous medium may be water or a mixture of water and a hydrophilic medium. For example, a volatile solvent such as ethanol or methanol or its vapor can be used as the hydrophilic medium. The aqueous medium may be a mixture of water and a volatile solvent such as ethanol or methanol, and is preferably water or a mixture of water and ethanol. The ratio of water to the volatile solvent or its vapor is not particularly limited, and may be, for example, 10:90 to 90:10 by mass. The proportion of water is preferably 30% by mass or more, and may be 40% by mass or 50% by mass or more.

The aqueous medium is preferably a liquid or gas containing water (including water vapor) at 10 to 230°C. The temperature of the aqueous medium may be 10°C or higher, 25°C or higher, 40°C or higher, 60°C or higher, or 100°C or higher, and may be 230°C or lower, 120°C or lower, 100°C or lower, or 90°C or lower. More specifically, when the aqueous medium is a gas (steam), the temperature of the aqueous medium is preferably 100 to 230°C, more preferably 100 to 120°C.

Methods for contacting the raw blended yarn with the aqueous medium include spraying the aqueous medium onto the raw blended yarn, immersing the raw blended yarn in the aqueous medium, and exposing the raw blended yarn to an environment filled with the steam of the aqueous medium.

The time of contact with the aqueous medium is adjusted appropriately depending on the type of raw material blended yarn, the temperature of the aqueous medium, the method of contact with the aqueous medium, etc. The time of contact with the aqueous medium may be, for example, 1 minute or more, 5 minutes or more, 10 minutes or more, or 15 minutes or more, and may be 30 minutes or less, 20 minutes or less, or 15 minutes or less. The contact with the aqueous medium may be performed under normal pressure or under reduced pressure (e.g., vacuum).

The raw material blended yarn that has been brought into contact with the aqueous medium may be washed as necessary. Washing can be carried out, for example, using the aqueous medium described above. The temperature of the aqueous medium during washing may be, for example, 10°C or higher, 20°C or higher, or 30°C or higher, and may be 50°C or lower, 45°C or lower, or 40°C or lower.

The raw blended yarn that has been brought into contact with the aqueous medium may be dried. There are no particular limitations on the drying method, and the drying may be natural drying or drying with hot air or hot rollers. There are no particular limitations on the drying temperature, and it may be, for example, 20 to 150°C, preferably 40 to 120°C, and more preferably 60 to 100°C. The drying time may be, for example, 5 minutes or more, or 10 minutes or more, and may be 30 minutes or less, or 20 minutes or less.

The fabric containing the bulky blended yarn of this embodiment may consist only of the bulky blended yarn, or may contain other yarns (e.g., spun yarn, twisted yarn, etc.). The fabric may be either a knitted fabric or a woven fabric, or a combination of both. Any known method can be used for manufacturing the knitted fabric or woven fabric that constitutes the fabric (knitting method or weaving method).

The present invention will be explained in more detail below based on examples. However, the present invention is not limited to the following examples.

<Manufacturing artificial proteins>
(1) Preparation of Plasmid Expression Strain An artificial protein (artificial fibroin) having the amino acid sequence shown in SEQ ID NO: 2 (PRT966) was designed.

Next, a nucleic acid encoding the designed artificial protein was 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. The nucleic acid was cloned into a cloning vector (pUC118). The nucleic acid was then excised by restriction enzyme treatment with NdeI and EcoRI, and then recombined into the protein expression vector pET-22b(+) to obtain an expression vector.

(2) Protein Expression E. coli BLR (DE3) was transformed with a pET22b(+) expression vector containing a nucleic acid encoding the designed artificial protein. 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 3) containing ampicillin so that the OD ₆₀₀ was 0.005. The culture solution temperature was kept at 30° C., and flask culture was performed until the OD ₆₀₀ reached 5 (about 15 hours), to obtain a seed culture solution.

The seed culture was added to a jar fermenter containing 500 mL of production medium (Table 4) so that the OD ₆₀₀ was 0.05. The culture temperature was kept at 37° C., and the pH was controlled to be constant at 6.9. The dissolved oxygen concentration in the culture 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 temperature was kept at 37°C, and the culture was controlled to a constant pH of 6.9. The dissolved oxygen concentration in the culture was maintained at 20% of the dissolved oxygen saturation concentration, and the culture was continued for 20 hours. After that, 1 M isopropyl-β-thiogalactopyranoside (IPTG) was added to the culture solution to a final concentration of 1 mM to induce the expression of the artificial protein. 20 hours after the addition of IPTG, the culture solution was centrifuged and the bacterial cells were collected. SDS-PAGE was performed using the bacterial cells prepared from the culture solution before and after the addition of IPTG, and the expression of the target artificial protein was confirmed by the appearance of a band of the target artificial protein size depending on the addition of IPTG.

(3) Protein purification The cells harvested 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 phenylmethylsulfonyl fluoride (PMSF), and the cells were disrupted with 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 it reached a high purity. 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 stirred with a stirrer at 60 ° C. for 30 minutes to dissolve. After dissolution, the solution was dialyzed against water using a dialysis tube (Cellulose tube 36/32 manufactured by Sanko Junyaku Co., Ltd.) The white aggregated protein obtained after dialysis was collected by centrifugation, and the water was removed using a freeze-dryer to collect a freeze-dried powder containing PRT966 as an artificial protein.

<Production of first fiber (artificial protein fiber)>
(1) Preparation of dope solution The freeze-dried powder of the artificial protein was added to dimethyl sulfoxide (DMSO) to a concentration of 24% by mass, and then LiCl was added as a dissolution promoter to a concentration of 4.0% by mass. The freeze-dried powder of the artificial protein was then dissolved using a shaker for 3 hours to obtain a DMSO solution of the artificial protein. Insoluble matter and bubbles in the obtained DMSO solution were removed to obtain a dope solution. The solution viscosity of the dope solution was 5000 cP (centipoise) at 90°C.

(2) Spinning The dope solution obtained as described above was used with the spinning apparatus 10 shown in Fig. 1 to perform known dry-wet spinning to obtain an artificial protein fiber. The obtained artificial protein fiber was wound around a bobbin. Dry-wet spinning was performed under the following conditions.
Temperature of coagulation liquid (methanol): 5 to 10°C
Stretching ratio: 4.52 times Drying temperature: 80°C

<Production of blended yarn>
The artificial protein fiber was tow-cut to produce a first sliver containing the artificial protein fiber. The cut length of the artificial protein fiber was about 150 mm to 250 mm. The worsted spinning method was used to produce the blended yarn.

Example 1
A pre-spinning process was carried out using the first sliver and the second sliver. This process is a process for turning the first sliver and the second sliver into rovings for post-spinning. The purpose of this process is to increase the parallelism of the fibers and mix them uniformly. A wool sliver was used as the second sliver. A commercially available wool sliver was used, and the fiber length was about 75 mm. In the pre-spinning process, for example, of the 10 slivers, 6 to 8 wool fibers and 2 to 4 artificial protein fibers are drawn together at a draft ratio of 2 to 6 times. This is repeated, for example, 5 times.

The post-spinning process was carried out using the roving yarn. Specifically, this process involves twisting the roving yarn while applying a draft. In this process, the number of twists was approximately 300 times/m, and the draft ratio was 25 to 30 times. The twist was applied in the Z direction. In the case of making a two-ply yarn, the number of twists was approximately 230 times/m, and the twist was applied in the S direction.

A skein of raw blended yarn obtained by the above method was created (2m40cm). The skein was set in a skein dyeing machine. Inside the skein dyeing machine, 100°C water was sprayed onto the skein for 15-20 minutes. The resulting skein was washed with 30-40°C water, dehydrated, and then dried with hot air at around 90°C for 15 minutes. This resulted in a bulky blended yarn made from artificial protein fiber and wool.

<Content of First Fiber>
The content of the first fiber was 30% by mass, based on the total mass of the blended yarn.

<Average fiber length>
The average length of the first fibers was 72.4 mm. The average length of the second fibers was 74.2 mm. The average length of the fibers is the average length measured according to JIS L 1015C.

<Shrinkage rate due to contact with water>
The shrinkage rate of the first fiber due to contact with water was 45%. The shrinkage rate of the second fiber due to contact with water was 10%. The "shrinkage rate due to contact with water" of the first fiber and the second fiber was measured in the same manner according to the following method. First, a plurality of fibers having the same length were bundled to obtain a fiber bundle. The obtained fiber bundle was attached with a 0.8 g lead weight and immersed in 95 ° C water for 10 minutes. After that, the fiber bundle was taken out of the water, and the fiber bundle was dried at room temperature for 2 hours with the 0.8 g lead weight still attached, and the length of the fiber bundle after drying was measured. Next, the "shrinkage rate due to contact with water (%)" of the fiber was calculated according to the following formula I. In formula I, L0 indicates the length of the fiber bundle before contact with water, and Ld indicates the length of the fiber bundle after shrinkage due to contact with water and then dried.
Formula I: Shrinkage rate = {1 - (Ld/L0)} x 100 (%)

<Number of crimps>
The crimp number of the first fiber was 8.0. The crimp number of the second fiber was 11.8. The crimp numbers were measured according to JIS L 1015.

<Bulkiness>
The bulkiness of the blended yarn obtained by the above method was 36.1 cm ³ /g. The bulkiness was measured according to JIS L 1095A method.

Example 2
A bulky blended yarn made of artificial protein fiber and silk was obtained in the same manner as in Example 1, except that a silk sliver was used as the second sliver. The raw blended yarn was produced by worsted spinning.

<Average fiber length>
The average length of the first fibers was 68.0 mm. The average length of the second fibers was 86.2 mm.

<Shrinkage rate due to contact with water>
The first fiber had a shrinkage of 45% when exposed to water, and the second fiber had a shrinkage of 10% when exposed to water.

<Number of crimps due to contact with water>
The number of crimps of the first fiber was 8.0. The number of crimps of the second fiber was 19.1. The average length of the first and second fibers, the shrinkage rate due to contact with water, and the number of crimps were measured in the same manner as in Example 1.

<Bulkiness>
The bulkiness of the blended yarn obtained by the above-mentioned method was 22.0 cm ³ /g. The bulkiness was measured in the same manner as in Example 1.

1...Extrusion device, 2...Undrawn yarn manufacturing device, 3...Wet heat drawing device, 4...Drying device, 6...Dope solution, 10...Spinning device, 20...Coagulation liquid tank, 21...Drawing bath, 36...Artificial protein fiber.

Claims

a first fiber comprising an artificial protein and capable of shrinking upon contact with water;
and a second fiber having a lower shrinkage rate upon contact with water than the first fiber.
A bulky blended yarn having a bulkiness of 10 cm 3 /g or more.
2. The bulky blended yarn of claim 1, wherein the bulkiness is 50 cm 3 /g or less.
The bulky blended yarn according to claim 1 or 2, wherein the shrinkage rate of the first fiber upon contact with water is 15% or more.
The bulky blended yarn according to claim 1 or 2, wherein the number of crimps of the first fiber is 5 or more.
The bulky blended yarn according to claim 1 or 2, wherein the content of the first fiber is 5% by mass or more based on the total mass of the bulky blended yarn.
The bulky blended yarn according to claim 1 or 2, wherein the average length of the first fibers is 48 mm or more and 170 mm or less.
The bulky blended yarn according to claim 1 or 2, wherein the second fiber is at least one of animal hair fiber and silk.
A step of blending a first sliver containing a first fiber that contains an artificial protein and can shrink when contacted with water with a second sliver containing a second fiber that has a shrinkage rate when contacted with water lower than that of the first fiber to obtain a raw blended yarn;
and a step of contacting the raw blended yarn with an aqueous medium to shrink at least the first fiber to obtain a bulky blended yarn.
A fabric comprising the bulky blended yarn according to claim 1 or 2.