Artificial fur and its manufacturing method

Abstract

The purpose of the present invention is to provide an artificial fur which has satisfactory moisture absorbency and requires a reduced amount of energy for the manufacture thereof. The artificial fur according to the present invention comprises artificial protein fibers.

Description

[Technical field]

[0001] The present invention relates to an artificial fur and a method for producing the same. [Background technology]

[0002] Artificial fur has been used as a substitute for natural fur. As described in Patent Document 1, for example, artificial fur is made of synthetic fibers such as acrylic fibers. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 63-6133 Summary of the Invention [Problem to be solved by the invention]

[0004] Unlike natural fur, which has limited supply, artificial fur can be mass-produced artificially, and so in recent years it has come to be used for a wider range of purposes, including clothing, accessories such as bags, carpets, stuffed toys, etc. Furthermore, most conventional artificial furs are made using acrylic fibers, which are light and warm like fluffy wool.

[0005] However, the artificial furs available to date have been made from synthetic fibers, which have poor moisture absorption properties, and because they are derived from petroleum, they inevitably require a huge amount of energy to manufacture.

[0006] In order to solve or reduce the above problems, it is conceivable to obtain an artificial fur using, for example, protein fibers. However, some protein fibers shrink when they come into contact with water, and there is a concern that artificial fur made using such protein fibers will undergo significant dimensional changes when they come into contact with water.

[0007] Moreover, artificial fur made of acrylic fiber, which is widely used in artificial fur, not only places a large burden on the environment, but also has problems such as being vulnerable to moisture and water, and the fibers stretching particularly when washed.

[0008] The present invention has been made in light of the above-mentioned circumstances, and its first object is to provide an artificial fur material which has sufficient moisture absorption properties and requires reduced energy for its production, and to provide a method for its production.

[0009] A second object of the present invention is to provide an artificial fur which has sufficient moisture absorption properties, requires less energy for its production, and is prevented as much as possible from undergoing dimensional changes due to contact with water.

[0010] A third object of the present invention is to provide an artificial fur that is excellent in functionality such as water resistance.

[0011] A fourth object of the present invention is to provide an artificial fur having excellent water resistance.

[0012] A fifth object of the present invention is to provide a method for advantageously producing artificial fur which has sufficient moisture absorption properties and requires reduced energy for production.

[0013] The sixth object of the present invention is to provide a method for advantageously producing artificial fur which has sufficient moisture absorption properties, requires less energy for production, and undergoes minimal dimensional change due to contact with water. [Means for solving the problem]

[0014] The present invention (first invention) for solving the first problem relates to, for example, the following inventions.

[0015] [1-1] Artificial fur, including artificial protein fibers.

[0016] [1-2] The artificial fur according to [1-1], wherein the artificial protein fiber contains an artificial structural protein fiber.

[0017] [1-3] The artificial fur according to [1-2], wherein the artificial structural protein fiber contains modified fibroin fiber.

[0018] [1-4] The artificial fur described in [1-3], wherein the modified fibroin fiber contains modified spider silk fibroin fiber.

[0019] [1-5] The artificial fur according to any one of [1-1] to [1-4], which has a limiting oxygen index (LOI) value of 26.0 or more.

[0020] [1-6] The artificial fur according to any one of [1-1] to [1-5], which has a maximum moisture absorption heat generation rate, calculated according to the following formula A, of more than 0.025° C. / g. Formula A: Maximum moisture absorption heat release rate = {(Maximum sample temperature when the sample is placed in a low humidity environment until the sample temperature reaches equilibrium and then transferred to a high humidity environment) - (sample temperature when the sample is placed in a low humidity environment until the sample temperature reaches equilibrium and then transferred to a high humidity environment)} (°C) / sample weight (g) [In formula A, the low humidity environment means an environment with a temperature of 20° C. and a relative humidity of 40%, and the high humidity environment means an environment with a temperature of 20° C. and a relative humidity of 90%.]

[0021] [1-7] The artificial fur according to [1-6], wherein the maximum moisture absorption heat generation rate is 0.031°C / g or more.

[0022] [1-8] The artificial fur according to any one of [1-1] to [1-7], which has a heat retention index calculated according to the following formula B of more than 0.18. Formula B: Heat retention index = Heat retention rate (%) / Sample weight (g / m 2 ) [In formula B, the heat retention rate (%) means the heat retention rate measured by the dry contact method (temperature 30°C, air speed 30 cm / sec), and is calculated by (1-a / b) x 100. a indicates the amount of heat dissipated through the test piece, and b indicates the amount of heat dissipated without passing through the test piece.] [1-9] The artificial fur described in [1-8], having a heat retention index of 0.22 or more.

[0023] The present invention (second invention) for solving the second problem relates to, for example, the following inventions.

[0024] [2-1] Artificial fur containing shrunk protein fibers.

[0025] [2-2] The artificial fur according to [2-1], wherein the protein fiber has a wet shrinkage rate, as defined by the following formula I, of 2% or more. Wet shrinkage rate = {1 - (length of protein fiber wetted by contact with water / length of protein fiber after spinning and before contact with water)} x 100 (%) ... (Equation I)

[0026] [2-3] The artificial fur according to [2-1] or [2-2], wherein the protein fiber has a dry shrinkage rate, as defined by the following formula II, of more than 7%. Dry shrinkage rate = {1 - (length of protein fiber in a dry state / length of protein fiber after spinning and before contact with water)} x 100 (%) ... (Formula II)

[0027] [2-4] The artificial fur according to any one of [2-1] to [2-3], wherein the protein fiber contains modified fibroin.

[0028] [2-5] The artificial fur described in [2-4], wherein the modified fibroin is modified spider silk fibroin.

[0029] [2-6] The artificial fur according to any one of [2-1] to [2-5], which has a limiting oxygen index (LOI) value of 26.0 or more.

[0030] [2-7] The artificial fur according to any one of [2-1] to [2-6], which has a maximum moisture absorption heat generation rate, calculated according to the following formula A, of more than 0.025° C. / g. Formula A: Maximum moisture absorption heat release rate = {(Maximum sample temperature when the sample is placed in a low humidity environment until the sample temperature reaches equilibrium and then transferred to a high humidity environment) - (sample temperature when the sample is placed in a low humidity environment until the sample temperature reaches equilibrium and then transferred to a high humidity environment)} (°C) / sample weight (g) [In formula A, the low humidity environment means an environment with a temperature of 20° C. and a relative humidity of 40%, and the high humidity environment means an environment with a temperature of 20° C. and a relative humidity of 90%.]

[0031] [2-8] The artificial fur according to [2-7], wherein the maximum moisture absorption heat generation rate is 0.031°C / g or more.

[0032] [2-9] The artificial fur according to any one of [2-1] to [2-8], which has a heat retention index calculated according to the following formula B of more than 0.18. Formula B: Heat retention index = Heat retention rate (%) / Sample weight (g / m 2 ) [In formula B, the heat retention rate (%) means the heat retention rate measured by the dry contact method (temperature 30°C, air speed 30 cm / sec), and is calculated by (1-a / b) x 100. a indicates the amount of heat dissipated through the test piece, and b indicates the amount of heat dissipated without passing through the test piece.] [2-10] The artificial fur described in [2-9], having a heat retention index of 0.22 or more.

[0033] The present invention (third invention) for solving the third problem relates to, for example, the following inventions.

[0034] [3-1] An artificial fur containing fibers and having functionality.

[0035] [3-2] The artificial fur according to [3-1], wherein the fibers include protein fibers.

[0036] [3-3] The artificial fur described in [3-2], wherein the protein fiber contains modified fibroin.

[0037] [3-4] The artificial fur described in [3-3], wherein the modified fibroin is modified spider silk fibroin.

[0038] [3-5] Contains a protein crosslinker, the protein crosslinked product has a polypeptide backbone, a first residue which is a residue of a first reacting agent having two or more first reactive groups capable of reacting with a protein to form a bond, and a second residue which is a residue of a second reacting agent having one second reactive group capable of reacting with the first reactive group to form a bond; at least one of the first residues bridges the polypeptide backbone; At least one of the first residues is attached to the polypeptide backbone at one end and to the second residue at the other end. The artificial fur according to any one of [3-1] to [3-4], wherein the artificial fur is bound to two residues.

[0039] [3-6] The artificial fur according to any one of [3-1] to [3-5], which comprises a modified hydroxyl group-containing polymer in which a functional group is bonded to a hydroxyl group-containing polymer.

[0040] [3-7] The artificial fur according to any one of [3-1] to [3-6], which has a limiting oxygen index (LOI) value of 26.0 or more.

[0041] [3-8] The artificial fur according to any one of [3-1] to [3-7], which has a maximum moisture absorption heat generation rate, calculated according to the following formula A, of more than 0.025° C. / g. Formula A: Maximum moisture absorption heat release rate = {(Maximum sample temperature when the sample is placed in a low humidity environment until the sample temperature reaches equilibrium and then transferred to a high humidity environment) - (sample temperature when the sample is placed in a low humidity environment until the sample temperature reaches equilibrium and then transferred to a high humidity environment)} (°C) / sample weight (g) [In formula A, the low humidity environment means an environment with a temperature of 20° C. and a relative humidity of 40%, and the high humidity environment means an environment with a temperature of 20° C. and a relative humidity of 90%.]

[0042] [3-9] The artificial fur according to [3-8], wherein the maximum moisture absorption heat generation rate is 0.031°C / g or more.

[0043] [3-10] The artificial fur according to any one of [3-1] to [3-9], which has a heat retention index calculated according to the following formula B of more than 0.18. Formula B: Heat retention index = Heat retention rate (%) / Sample weight (g / m 2 ) [In formula B, the heat retention rate (%) means the heat retention rate measured by the dry contact method (temperature 30°C, air speed 30 cm / sec), and is calculated by (1-a / b) x 100. a indicates the amount of heat dissipated through the test piece, and b indicates the amount of heat dissipated without passing through the test piece.] [3-11] The artificial fur described in [3-10], having a heat retention index of 0.22 or more.

[0044] The present invention (fourth invention) for solving the fourth problem relates to, for example, the following inventions.

[0045] [4-1] An artificial fur comprising fibers and a substance that provides water resistance.

[0046] [4-2] The artificial fur described in [4-1], wherein the fibers include protein fibers.

[0047] [4-3] The artificial fur described in [4-2], wherein the protein fiber contains modified fibroin.

[0048] [4-4] The artificial fur described in [4-3], wherein the modified fibroin is modified spider silk fibroin.

[0049] [4-5] The artificial fur according to any one of [4-2] to [4-4], wherein the modified fibroin and the water-resistance imparting substance are covalently bonded to each other.

[0050] [4-6] The artificial fur according to any one of [4-1] to [4-5], wherein the water-resistance imparting substance is at least one selected from the group consisting of silicone-based polymers and fluorine-based polymers.

[0051] [4-7] The artificial fur according to any one of [4-1] to [4-6], which has a limiting oxygen index (LOI) value of 26.0 or more.

[0052] [4-8] The artificial fur according to any one of [4-1] to [4-7], which has a maximum moisture absorption heat generation rate, calculated according to the following formula A, of more than 0.025° C. / g. Formula A: Maximum moisture absorption heat release rate = {(Maximum sample temperature when the sample is placed in a low humidity environment until the sample temperature reaches equilibrium and then transferred to a high humidity environment) - (sample temperature when the sample is placed in a low humidity environment until the sample temperature reaches equilibrium and then transferred to a high humidity environment)} (°C) / sample weight (g) [In formula A, the low humidity environment means an environment with a temperature of 20° C. and a relative humidity of 40%, and the high humidity environment means an environment with a temperature of 20° C. and a relative humidity of 90%.]

[0053] [4-9] The artificial fur according to [4-8], wherein the maximum moisture absorption heat generation rate is 0.031°C / g or more.

[0054] [4-10] The artificial fur according to any one of [4-1] to [4-9], which has a heat retention index calculated according to the following formula B of more than 0.18. Formula B: Heat retention index = Heat retention rate (%) / Sample weight (g / m 2 ) [In formula B, the heat retention rate (%) means the heat retention rate measured by the dry contact method (temperature 30°C, air speed 30 cm / sec), and is calculated by (1-a / b) x 100. a indicates the amount of heat dissipated through the test piece, and b indicates the amount of heat dissipated without passing through the test piece.] [4-11] The artificial fur described in [4-10], having a heat retention index of 0.22 or more.

[0055] The present invention (the fifth invention) for solving the above fifth problem relates to, for example, the following inventions.

[0056] [5-1] The method for producing artificial fur comprises the steps of obtaining a pile fabric having pile protruding from one or both sides of the fabric using fibers containing artificial protein fibers, and cutting the loops of the pile to form cut pile.

[0057] The present invention (sixth invention) for solving the sixth object relates to, for example, the following inventions.

[0058] [6-1] The method for producing artificial fur comprises the steps of obtaining a pile fabric having pile protruding from one or both sides of the fabric using shrink-proof protein fibers, and cutting the loops of the pile to form cut pile.

[0059] [6-2] A method for producing artificial fur, comprising the steps of: obtaining a pile fabric having pile protruding from one or both sides of the fabric using fibers containing protein fibers; cutting the loops of the pile to form cut pile; and shrink-proofing the pile fabric. Effect of the Invention

[0060] According to the first aspect of the present invention, it is possible to provide artificial fur that has sufficient moisture absorption properties and requires reduced energy for its production.

[0061] According to the second aspect of the present invention, it is possible to provide artificial fur that has sufficient moisture absorption properties, requires less energy for production, and is prevented from undergoing dimensional changes due to contact with water as much as possible.

[0062] According to the third invention, an artificial fur coat having excellent functionality such as water resistance can be provided.

[0063] According to the fourth aspect of the present invention, it is possible to provide artificial fur that is excellent in water resistance.

[0064] According to the fifth aspect of the present invention, it is possible to provide a method for advantageously producing artificial fur that has sufficient moisture absorption properties and requires reduced energy for production.

[0065] According to the sixth invention, it is possible to provide a method for advantageously producing artificial fur which has sufficient moisture absorption properties, requires less energy for production, and undergoes minimal dimensional change due to contact with water. [Brief description of the drawings]

[0066] [Figure 1] FIG. 2 is a schematic diagram showing an example of a domain sequence of a modified fibroin. [Diagram 2] FIG. 1 shows the distribution of z / w (%) values ​​of naturally occurring fibroin. [Diagram 3] FIG. 1 shows the distribution of x / y (%) values ​​of naturally derived fibroin. [Figure 4] FIG. 2 is a schematic diagram showing an example of a domain sequence of a modified fibroin. [Diagram 5] FIG. 2 is a schematic diagram showing an example of a domain sequence of a modified fibroin. [Figure 6] FIG. 1 is an explanatory diagram illustrating an example of a spinning apparatus for producing protein fibers (filaments). [Figure 7] 1 is a graph showing the results of evaluating the water shrinkage rate of produced protein fibers. [Figure 8]1 is a graph showing an example of the results of a moisture absorption heat generation test. [Figure 9] 1 is a photograph showing the surface of the artificial fur produced in Test Example 13. [Figure 10] 13 is a photograph showing the side of the artificial fur produced in Test Example 13. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0067] Hereinafter, an embodiment of the present invention will be described in detail. However, the present invention is not limited to the following embodiment.

[0068] <First embodiment> The artificial fur according to the first embodiment of the first invention contains artificial protein fibers.

[0069] Artificial protein fibers are fibers spun from proteins as the main raw material. Examples of proteins include natural proteins and recombinant proteins (artificial proteins). Examples of recombinant proteins include any protein that can be produced on an industrial scale, such as proteins that can be used for industrial purposes, proteins that can be used for medical purposes, structural proteins, etc. Specific examples of proteins that can be used for industrial or medical purposes include enzymes, regulatory proteins, receptors, peptide hormones, cytokines, membrane or transport proteins, antigens used in vaccinations, vaccines, antigen-binding proteins, immunostimulating proteins, allergens, full-length antibodies, or antibody fragments or derivatives. Specific examples of structural proteins include spider silk, silkworm silk, keratin, collagen, elastin, and resilin, as well as proteins derived therefrom. The protein used is preferably modified fibroin, more preferably modified spider silk fibroin, because of its excellent heat retention, moisture absorption and heat generation properties, and / or flame retardancy. If the protein is modified fibroin (preferably modified spider silk fibroin), the artificial fur of this embodiment can be further endowed with heat retention, moisture absorption and heat generation, and / or flame retardancy, making it even more valuable as an artificial fur.

[0070] In this specification, fibers spun from structural proteins, modified fibroins, and modified spider silk fibroin are referred to as artificial structural protein fibers, modified fibroin fibers, and modified spider silk fibroin fibers, respectively.

[0071] The modified fibroin according to this embodiment is represented by the formula 1: [(A) n Motif-REP] m Or formula 2: [(A) n Motif-REP] m -(A) n The modified fibroin is a protein containing a domain sequence represented by a motif. The modified fibroin may have further amino acid sequences (N-terminal sequence and C-terminal sequence) added to either or both of the N-terminal and C-terminal sides of the domain sequence. The N-terminal sequence and the C-terminal sequence are typically, but not limited to, regions that do not have repetitions of amino acid motifs characteristic of fibroin and consist of about 100 amino acid residues.

[0072] As used herein, the term "modified fibroin" refers to artificially produced fibroin (artificial fibroin). The modified fibroin may be a fibroin whose domain sequence is different from the amino acid sequence of naturally occurring fibroin, or may be a fibroin whose domain sequence is identical to the amino acid sequence of naturally occurring fibroin. The "naturally occurring fibroin" referred to in this specification is also a fibroin represented by the formula 1: [(A) n Motif-REP] m Or formula 2: [(A) n Motif-REP] m -(A) n A protein containing a domain sequence represented by a motif.

[0073] A "modified fibroin" may be one that uses the amino acid sequence of naturally occurring fibroin as is, or one that has had its amino acid sequence modified based on the amino acid sequence of naturally occurring fibroin (for example, one that has had its amino acid sequence modified by modifying the gene sequence of a cloned naturally occurring fibroin), or one that has been artificially designed and synthesized independent of naturally occurring fibroin (for example, one having a desired amino acid sequence obtained by chemically synthesizing a nucleic acid that codes for a designed amino acid sequence).

[0074] As used herein, the term "domain sequence" refers to a crystalline region specific to fibroin (typically, the (A) n A motif) and an amorphous region (typically corresponding to REP of an amino acid sequence), and the amino acid sequence is represented by the formula 1: [(A) n Motif-REP] m Or formula 2: [(A) n Motif-REP] m -(A) n The amino acid sequence represented by the motif (A) n The motif shows an amino acid sequence mainly composed of alanine residues, and the number of amino acid residues is 2 to 27. (A) n The number of amino acid residues in the 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. n The ratio of the number of alanine residues to the total number of amino acid residues in the 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 motif is composed of only alanine residues). n At least seven of the motifs 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. (A) nThe motifs may be identical to each other or different from each other in amino acid sequence, and the multiple REPs may be identical to each other or different from each other in amino acid sequence.

[0075] The modified fibroin according to the present embodiment can be obtained, for example, by modifying the amino acid sequence of the cloned gene sequence of naturally occurring fibroin by, for example, substituting, deleting, inserting, and / or adding one or more amino acid residues. Substitution, deletion, insertion, and / or addition of amino acid residues can be performed by methods well known to those skilled in the art, such as site-specific mutagenesis. Specifically, it can be performed according to the methods described in literature, such as Nucleic Acid Res. 10, 6487 (1982) and Methods in Enzymology, 100, 448 (1983).

[0076] Naturally occurring fibroin has the formula 1: [(A) n Motif-REP] m Or formula 2: [(A) n Motif-REP] m -(A) n A protein containing a domain sequence represented by a motif, specifically, for example, fibroin produced by insects or arachnids.

[0077] Examples of fibroin produced by insects include Bombyx mori, Bombyx mandarina, Antheraea yamamai, Anteraea pernyi, Eriogyna pyretorum, Pilosamia cynthia ricini, and Samia serrata. Examples of silk proteins include those produced by silkworms such as Bombyx mori (Caligura cynthia), Bombyx mori (Caligura japonica), Bombyx mori (Antheraea mylitta), and Bombyx mori (Antheraea assama), and hornet silk proteins excreted by the larvae of the Japanese hornet (Vespa simillima xanthoptera).

[0078] A more specific example of fibroin produced by an insect is, for example, silkworm fibroin L chain (GenBank accession numbers M76430 (nucleotide sequence) and AAA27840.1 (amino acid sequence)).

[0079] Examples of fibroin produced by spiders include spider silk proteins produced by spiders belonging to the order Araneae. More specifically, spiders belonging to the genus Araneus, such as the Japanese orb spider, the Japanese garden orb spider, the red orb spider, the green orb spider, and the like; spiders belonging to the genus Neoscona, such as the Japanese orb spider, the Japanese house orb spider, and the Japanese orb spider; spiders belonging to the genus Pronus, such as the Japanese orb spider; spiders belonging to the genus Cyrtarachne, such as the Japanese orb spider and the Japanese orb spider; spiders belonging to the genus Togegumo and the Japanese orb spider; Spiders of the genus Gasteracantha, spiders of the genus Ordgarius such as the Orbweaver Spider and the Orbweaver Spider, spiders of the genus Argiope such as the Orbweaver Spider, the Orbweaver Spider and the Orbweaver Spider, spiders of the genus Arachnura such as the Orbweaver Spider, spiders of the genus Acusilas such as the Breeding Spider, the Orbweaver Spider and the Orbweaver Spider, spiders of the genus Cytophorus such as the Orbweaver Spider, the Orbweaver Spider and the Orbweaver Spider, spider silk proteins produced by spiders belonging to the genus Poltys such as the Poltys spider, spiders belonging to the genus Cyclosa such as the Japanese bush spider, the four-headed bush spider, the round bush spider and the black bush spider, and spiders belonging to the genus Chorizopes such as the Japanese bush spider, as well as spiders belonging to the genus Tetragnatha such as the long-legged spider, the long-legged spider, the Japanese bush spider and the scaled long-legged spider, spiders belonging to the genus Orbweaver spider, Spiders of the genus Leucauge, such as the medium-sized orb-weaver spider and the small orb-weaver spider; spiders of the genus Nephila, such as the orb-weaver spider and the giant orb-weaver spider; spiders of the genus Menosira, such as the golden spider; spiders of the genus Dyschiriognatha, such as the long-legged spider; spiders of the genus Latrodectus, such as the black widow spider, the redback spider, the gray widow spider, and the three-spotted widow spider;and spider silk proteins produced by spiders belonging to the family Tetragnathidae, such as spiders belonging to the genus Euprosthenops. Examples of spider silk proteins include dragline proteins such as MaSp (MaSp1 and MaSp2) and ADF (ADF3 and ADF4), MiSp (MiSp1 and MiSp2), AcSp, PySp, Flag, etc.

[0080] More specific examples of spider silk proteins produced by spiders include fibroin-3 (adf-3) [derived from Araneus diadematus] (GenBank accession numbers AAC47010 (amino acid sequence), U47855 (nucleotide sequence)), fibroin-4 (adf-4) [derived from Araneus diadematus] (GenBank accession numbers AAC47011 (amino acid sequence), U47856 (nucleotide sequence)), dragline silk protein spidroin 1 [derived from Nephila clavipes] (GenBank accession numbers AAC04504 (amino acid sequence), U37520 (nucleotide sequence)), major ampullate spidroin 1 [derived from Latrodectus hesperus] (GenBank accession numbers ABR68856 (amino acid sequence), EF595246 (nucleotide sequence)), dragline silk protein spidroin 2 [derived from Nephila clavata] (GenBank accession numbers AAL32472 (amino acid sequence), AF441245 (nucleotide sequence)), major ampullate spidroin 1 [Euprosthenops australis] (GenBank accession numbers CAJ00428 (amino acid sequence), AJ973155 (nucleotide sequence)), and major ampullate spidroin 2 [Euprosthenops australis] (GenBank accession numbers CAM32249.1 (amino acid sequence), AM490169 (nucleotide sequence)), minor ampullate silk protein 1 [Nephila clavipes] (GenBank accession number AAC14589.1 (amino acid sequence)), minor ampullate silk protein 2 [Nephila clavipes] (GenBank accession number AAC14591.1 (amino acid sequence)), minor ampullate spidroin-like protein [Nephilengys cruentata] (GenBank accession number ABR37278.1 (amino acid sequence) and the like.

[0081] More specific examples of naturally occurring fibroin include those listed in the NCBI An example is fibroin, whose sequence information is registered in GenBank. For example, from among the sequences registered in NCBI GenBank that contain INV as DIVISION, it can be confirmed by extracting sequences with spidroin, ampullate, fibroin, "silk and polypeptide," or "silk and protein" as keywords in DEFINITION, a specific product character string in CDS, and a specific character string in TISSUE TYPE in SOURCE.

[0082] The modified fibroin in this embodiment may be modified silk fibroin (a silk protein produced by silkworms with a modified amino acid sequence) or modified spider silk fibroin (a spider silk protein produced by spiders with a modified amino acid sequence).

[0083] Specific examples of modified fibroins include a modified fibroin derived from the major ampullate gland protein of spiders (first modified fibroin), a modified fibroin having a domain sequence with a reduced content of glycine residues (second modified fibroin), (A) n A modified fibroin having a domain sequence with a reduced content of motifs (third modified fibroin), the content of glycine residues, and (A) n These include a modified fibroin with a reduced motif content (the fourth modified fibroin), a modified fibroin with a domain sequence that includes a region of high local hydrophobicity index (the fifth modified fibroin), and a modified fibroin with a domain sequence with a reduced content of glutamine residues (the sixth modified fibroin).

[0084] The first modified fibroin is represented by the formula 1: [(A) n Motif-REP] m In the first modified fibroin, a protein having a domain sequence represented by the formula: n The number of amino acid residues in the motif is preferably an integer of 3 to 20, more preferably an integer of 4 to 20, even more preferably an integer of 8 to 20, even more preferably an integer of 10 to 20, even more preferably an integer of 4 to 16, particularly preferably an integer of 8 to 16, and most preferably an integer of 10 to 16. The first modified fibroin has a number of amino acid residues constituting REP in formula 1 of preferably 10 to 200 residues, more preferably 10 to 150 residues, even more preferably 20 to 100 residues, and even more preferably 20 to 75 residues. The first modified fibroin has a number of amino acid residues constituting REP in formula 1: [(A) n Motif-REP] mThe total number of glycine residues, serine residues and alanine residues contained in the amino acid sequence represented by the formula (I) is preferably 40% or more, more preferably 60% or more, and even more preferably 70% or more, based on the total number of amino acid residues.

[0085] The first modified fibroin has the formula 1: [(A) n Motif-REP] m and the C-terminal sequence is an amino acid sequence shown in any one of SEQ ID NOs: 1 to 3 or an amino acid sequence having 90% or more homology to the amino acid sequence shown in any one of SEQ ID NOs: 1 to 3.

[0086] The amino acid sequence shown in SEQ ID NO:1 is identical to the amino acid sequence consisting of 50 amino acid residues at the C-terminus of the amino acid sequence of ADF3 (GI:1263287, NCBI), the amino acid sequence shown in SEQ ID NO:2 is identical to the amino acid sequence obtained by removing 20 residues from the C-terminus of the amino acid sequence shown in SEQ ID NO:1, and the amino acid sequence shown in SEQ ID NO:3 is identical to the amino acid sequence obtained by removing 29 residues from the C-terminus of the amino acid sequence shown in SEQ ID NO:1.

[0087] A more specific example of the first modified fibroin is (1-i) a modified fibroin comprising an amino acid sequence shown in SEQ ID NO: 4 (recombinant spider silk protein ADF3KaiLargeNRSH1), or (1-ii) an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 4. The sequence identity is preferably 95% or more.

[0088] The amino acid sequence shown in SEQ ID NO:4 is an amino acid sequence of ADF3 with an amino acid sequence (SEQ ID NO:5) consisting of an initiation codon, a His10 tag, and an HRV3C protease (Human rhinovirus 3C protease) recognition site added to the N-terminus, in which the repeat region at positions 1 to 13 is increased approximately twice and mutated so that translation terminates at amino acid residue 1154. The amino acid sequence at the C-terminus of the amino acid sequence shown in SEQ ID NO:4 is identical to the amino acid sequence shown in SEQ ID NO:3.

[0089] The modified fibroin of (1-i) may consist of the amino acid sequence shown in SEQ ID NO:4.

[0090] The second modified fibroin has an amino acid sequence in which the domain sequence has a reduced content of glycine residues compared to naturally-derived fibroin. It can be said that the second modified fibroin has an amino acid sequence in which at least one or more glycine residues in REP have been replaced with another amino acid residue compared to naturally-derived fibroin.

[0091] The second modified fibroin may have an amino acid sequence in which, compared to a naturally occurring fibroin, at least one glycine residue in at least one motif sequence selected from GGX and GPGXX (wherein G represents a glycine residue, P represents a proline residue, and X represents an amino acid residue other than glycine) in REP is replaced with another amino acid residue in at least one or more of the motif sequences.

[0092] In the second modified fibroin, the proportion of the motif sequence in which the above-mentioned glycine residue is replaced with another amino acid residue may be 10% or more relative to the total motif sequence.

[0093] The second modified fibroin has the formula 1: [(A) n Motif-REP] m(A) is located at the most C-terminal side of the domain sequence. n The total number of amino acid residues in the amino acid sequence consisting of XGX (where X represents an amino acid residue other than glycine) contained in all REPs in the sequence excluding the sequence from the motif to the C-terminus of the domain sequence is z, and the amino acid sequence located at the most C-terminus side from the domain sequence is (A). n When the total number of amino acid residues in the sequence excluding the sequence from the motif to the C-terminus of the domain sequence is w, the z / w ratio may be 30% or more, 40% or more, 50% or more, or 50.9% or more. (A) n The number of alanine residues relative to the total number of amino acid residues in the motif may be 83% or more, but is preferably 86% or more, more preferably 90% or more, even more preferably 95% or more, and even more preferably 100% (meaning that it is composed only of alanine residues).

[0094] The second modified fibroin is preferably one in which one glycine residue of the GGX motif is replaced with another amino acid residue to increase the content of the amino acid sequence consisting of XGX. The second modified fibroin preferably has a content of the amino acid sequence consisting of GGX in the domain sequence of 30% or less, more preferably 20% or less, even more preferably 10% or less, even more preferably 6% or less, even more preferably 4% or less, and particularly preferably 2% or less. The content of the amino acid sequence consisting of GGX in the domain sequence can be calculated by the same method as the calculation method for the content (z / w) of the amino acid sequence consisting of XGX below.

[0095] The method for calculating z / w will be described in more detail. First, the formula 1: [(A) n Motif-REP] m In a fibroin (modified fibroin or naturally-occurring fibroin) containing a domain sequence represented by the formula: nAn amino acid sequence consisting of XGX is extracted from all REPs contained in the sequence excluding the sequence from the motif to the C-terminus of the domain sequence. The total number of amino acid residues that make up XGX is z. For example, if 50 amino acid sequences consisting of XGX are extracted (no overlaps), z is 50 x 3 = 150. In addition, for example, in the case of an amino acid sequence consisting of XGXGX, if there are Xs contained in two XGXs (the central X), the overlaps are subtracted from the calculation (in the case of XGXGX, it is 5 amino acid residues). w is the number of amino acid residues (A) located at the most C-terminus side from the domain sequence. n It is the total number of amino acid residues contained in the sequence excluding the sequence from the motif to the C-terminus of the domain sequence. For example, in the case of the domain sequence shown in Figure 1, w is 4 + 50 + 4 + 100 + 4 + 10 + 4 + 20 + 4 + 30 = 230 ((A) located at the most C-terminus side). n (The motif is excluded.) Next, z / w (%) can be calculated by dividing z by w.

[0096] Here, the z / w ratio in naturally derived fibroin will be described. First, as described above, fibroins whose amino acid sequence information is registered in NCBI GenBank were confirmed by the method exemplified above, and 663 types of fibroin (of which, 415 types were spider-derived fibroin) were extracted. Of all the extracted fibroins, those with the formula 1: [(A) n Using the above-mentioned calculation method, z / w was calculated from the amino acid sequence of naturally-occurring fibroin, which contains a domain sequence represented by the motif [-REP]m and in which the content of the amino acid sequence consisting of GGX in the fibroin is 6% or less. The results are shown in Figure 2. The horizontal axis of Figure 2 indicates z / w (%), and the vertical axis indicates frequency. As is clear from Figure 2, z / w in all naturally-occurring fibroins is less than 50.9% (the highest being 50.86%).

[0097] In the second modified fibroin, z / w is preferably 50.9% or more, more preferably 56.1% or more, even more preferably 58.7% or more, even more preferably 70% or more, and even more preferably 80% or more. There is no particular upper limit to z / w, but it may be, for example, 95% or less.

[0098] The second modified fibroin can be obtained, for example, by modifying the gene sequence of a cloned naturally-derived fibroin by substituting at least a part of the base sequence encoding a glycine residue to encode another amino acid residue. In this case, one glycine residue in the GGX motif and the GPGXX motif may be selected as the glycine residue to be modified, or may be substituted so that z / w is 50.9% or more. Alternatively, for example, an amino acid sequence satisfying the above-mentioned aspects may be designed from the amino acid sequence of a naturally-derived fibroin, and a nucleic acid encoding the designed amino acid sequence may be chemically synthesized to obtain the second modified fibroin. In either case, in addition to the modification equivalent to substituting the glycine residue in REP with another amino acid residue from the amino acid sequence of a naturally-derived fibroin, the amino acid sequence may be modified by substituting, deleting, inserting and / or adding one or more amino acid residues.

[0099] The other amino acid residue is not particularly limited as long as it is an amino acid residue other than a glycine residue, but is preferably a hydrophobic amino acid residue such as a valine (V) residue, a leucine (L) residue, an isoleucine (I) residue, a methionine (M) residue, a proline (P) residue, a phenylalanine (F) residue, or a tryptophan (W) residue, or a hydrophilic amino acid residue such as a glutamine (Q) residue, an asparagine (N) residue, a serine (S) residue, a lysine (K) residue, or a glutamic acid (E) residue, more preferably a valine (V) residue, a leucine (L) residue, an isoleucine (I) residue, a phenylalanine (F) residue, or a glutamine (Q) residue, and even more preferably a glutamine (Q) residue.

[0100] More specific examples of the second modified fibroin include (2-i) a modified fibroin comprising an amino acid sequence shown in SEQ ID NO: 6 (Met-PRT380), SEQ ID NO: 7 (Met-PRT410), SEQ ID NO: 8 (Met-PRT525) or SEQ ID NO: 9 (Met-PRT799), or (2-ii) an amino acid sequence having 90% or more sequence identity to the amino acid sequence shown in SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8 or SEQ ID NO: 9.

[0101] The modified fibroin (2-i) will be described. The amino acid sequence shown in SEQ ID NO:6 is obtained by replacing all GGX in the REP of the amino acid sequence shown in SEQ ID NO:10 (Met-PRT313) corresponding to naturally-occurring fibroin with GQX. The amino acid sequence shown in SEQ ID NO:7 is obtained by replacing every third amino acid (A) from the N-terminus to the C-terminus of the amino acid sequence shown in SEQ ID NO:6. n The motif was deleted, and the C-terminal sequence was further amplified with [(A) n The amino acid sequence shown in SEQ ID NO:8 is a sequence in which each of (A) of the amino acid sequence shown in SEQ ID NO:7 is inserted. n Two alanine residues were inserted at the C-terminus of the motif, and some glutamine (Q) residues were further replaced with serine (S) residues, with some amino acids deleted at the C-terminus to have approximately the same molecular weight as SEQ ID NO: 7. The amino acid sequence shown in SEQ ID NO: 9 has a predetermined hinge sequence and His tag sequence added to the C-terminus of a sequence in which the 20 domain sequence regions present in the amino acid sequence shown in SEQ ID NO: 7 (with the exception that several amino acid residues at the C-terminus of said regions have been replaced) are repeated four times.

[0102] The z / w value in the amino acid sequence shown in SEQ ID NO: 10 (corresponding to naturally derived fibroin) is 46.8%. The z / w values ​​in the amino acid sequence shown in SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, and SEQ ID NO: 9 are 58.7%, 70.1%, 66.1%, and 70.0%, respectively. Furthermore, the x / y values ​​in the jagged ratio (described later) of 1:1.8 to 11.3 in the amino acid sequences shown in SEQ ID NO: 10, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, and SEQ ID NO: 9 are 15.0%, 15.0%, 93.4%, 92.7%, and 89.8%, respectively.

[0103] The modified fibroin (2-i) may consist of the amino acid sequence shown in SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8 or SEQ ID NO:9.

[0104] The modified fibroin of (2-ii) contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8 or SEQ ID NO: 9. The modified fibroin of (2-ii) also contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8 or SEQ ID NO: n Motif-REP] m It is a protein comprising a domain sequence represented by the following formula: The sequence identity is preferably 95% or more.

[0105] The modified fibroin (2-ii) preferably has a sequence identity of 90% or more with the amino acid sequence shown in SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8 or SEQ ID NO:9, and has a z / w ratio of 50.9% or more, where z is the total number of amino acid residues in the amino acid sequence consisting of XGX (wherein X represents an amino acid residue other than glycine) contained in REP, and w is the total number of amino acid residues in REP in the domain sequence.

[0106] The second modified fibroin may contain a tag sequence at either or both of the N-terminus and C-terminus, which allows for isolation, immobilization, detection, visualization, etc. of the modified fibroin.

[0107] 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). The His tag is a short peptide consisting of about 4 to 10 histidine residues lined up, and has the property of specifically binding to metal ions such as nickel, and can be used to isolate modified fibroin by metal chelating chromatography. A specific example of a tag sequence is the amino acid sequence shown in SEQ ID NO: 11 (an amino acid sequence including a His tag sequence and a hinge sequence).

[0108] Furthermore, tag sequences such as glutathione-S-transferase (GST) that specifically binds to glutathione, and maltose-binding protein (MBP) that specifically binds to maltose can also be used.

[0109] Furthermore, an "epitope tag" utilizing an antigen-antibody reaction can also be used. By adding an antigenic peptide (epitope) as a tag sequence, an antibody against the epitope can be bound. Examples of epitope tags include HA (peptide sequence of influenza virus hemagglutinin) tag, myc tag, and FLAG tag. By using an epitope tag, the modified fibroin can be easily purified with high specificity.

[0110] 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 the protease, the modified fibroin from which the tag sequence has been cleaved can be recovered.

[0111] More specific examples of modified fibroins containing a tag sequence include (2-iii) modified fibroins containing an amino acid sequence shown in SEQ ID NO: 12 (PRT380), SEQ ID NO: 13 (PRT410), SEQ ID NO: 14 (PRT525) or SEQ ID NO: 15 (PRT799), or (2-iv) an amino acid sequence having 90% or more sequence identity to the amino acid sequence shown in SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14 or SEQ ID NO: 15.

[0112] The amino acid sequences shown in SEQ ID NO:16 (PRT313), SEQ ID NO:12, SEQ ID NO:13, SEQ ID NO:14 and SEQ ID NO:15 are obtained by adding the amino acid sequence shown in SEQ ID NO:11 (including the His tag sequence and hinge sequence) to the N-terminus of the amino acid sequences shown in SEQ ID NO:10, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8 and SEQ ID NO:9, respectively.

[0113] The modified fibroin (2-iii) may consist of the amino acid sequence shown in SEQ ID NO:12, SEQ ID NO:13, SEQ ID NO:14 or SEQ ID NO:15.

[0114] The modified fibroin of (2-iv) contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, or SEQ ID NO: 15. The modified fibroin of (2-iv) also ... n Motif-REP] m It is a protein comprising a domain sequence represented by the following formula: The sequence identity is preferably 95% or more.

[0115] The modified fibroin (2-iv) has a sequence identity of 90% or more with the amino acid sequence shown in SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14 or SEQ ID NO: 15, and preferably has a z / w ratio of 50.9% or more, where z is the total number of amino acid residues in the amino acid sequence consisting of XGX (wherein X represents an amino acid residue other than glycine) contained in REP, and w is the total number of amino acid residues in REP in the domain sequence.

[0116] The second modified fibroin may contain a secretion signal for releasing the protein produced in the recombinant protein production system to the outside of the host. The sequence of the secretion signal can be appropriately set depending on the type of the host.

[0117] The third modified fibroin has a domain sequence different from that of naturally occurring fibroin, as follows: (A) n The third modified fibroin domain sequence has an amino acid sequence with a reduced content of motifs compared to naturally occurring fibroin. n It can be said that it has an amino acid sequence corresponding to the deletion of the motif.

[0118] The third modified fibroin was derived from naturally occurring fibroin (A). n It may have an amino acid sequence corresponding to a 10 to 40% deletion of the motif.

[0119] The third modified fibroin has a domain sequence that is different from that of naturally-occurring fibroin in that it has at least one to three (A) n One (A) per motif n It may have an amino acid sequence corresponding to the deletion of the motif.

[0120] The third modified fibroin has a domain sequence that is at least two consecutive domains from the N-terminus to the C-terminus, as compared with naturally occurring fibroin (A). n Deletion of the motif and one (A) n It may have an amino acid sequence corresponding to repeated deletion of the motif in this order.

[0121] The third modified fibroin has a domain sequence in which at least every third domain from the N-terminus to the C-terminus is (A) n It may have an amino acid sequence corresponding to the deletion of the motif.

[0122] The third modified fibroin has the formula 1: [(A) n Motif-REP] m The domain sequence is represented by the following two adjacent sequences from the N-terminus to the C-terminus: n The number of amino acid residues in the REP of the motif-REP] unit is compared in sequence. When the number of amino acid residues in the REP with the smaller number of amino acid residues is set to 1, the ratio of the number of amino acid residues in the other REP is 1.8 to 11.3 in two adjacent [(A) n When the maximum sum of the numbers of amino acid residues in the motif-REP units is x and the total number of amino acid residues in the domain sequence is y, the amino acid sequence may have an x / y ratio of 20% or more, 30% or more, 40% or more, or 50% or more. (A) n The number of alanine residues relative to the total number of amino acid residues in the motif may be 83% or more, but is preferably 86% or more, more preferably 90% or more, even more preferably 95% or more, and even more preferably 100% (meaning that it is composed only of alanine residues).

[0123] The method of calculating x / y will be described in more detail with reference to Fig. 1. Fig. 1 shows the domain sequence of the modified fibroin excluding the N-terminal sequence and the C-terminal sequence. The domain sequence is as follows from the N-terminal side (left side): (A) n Motif-First REP (50 amino acid residues)-(A) n Motif-Second REP (100 amino acid residues)-(A) n Motif-3 REP (10 amino acid residues)-(A) n Motif-4th REP (20 amino acid residues)-(A) n Motif-5 REP (30 amino acid residues)-(A) n It has a sequence called a motif.

[0124] Two adjacent [(A) n The motif-REP] units are selected sequentially from the N-terminus to the C-terminus, without overlapping. nA motif-REP] unit may be present. In FIG. 1, pattern 1 (comparison of the first REP with the second REP, and comparison of the third REP with the fourth REP), pattern 2 (comparison of the first REP with the second REP, and comparison of the fourth REP with the fifth REP), pattern 3 (comparison of the second REP with the third REP, and comparison of the fourth REP with the fifth REP), and pattern 4 (comparison of the first REP with the second REP) are shown. It should be noted that there are other selection methods.

[0125] Next, for each pattern, select two adjacent [(A) n The number of amino acid residues of each REP in the motif-REP unit is compared. The comparison is performed by determining the ratio of the number of amino acid residues of the other REP to the number of amino acid residues of the one with fewer amino acid residues set as 1. For example, when comparing the first REP (50 amino acid residues) with the second REP (100 amino acid residues), the ratio of the number of amino acid residues of the second REP is 100 / 50=2 when the number of amino acid residues of the first REP with fewer amino acid residues is set as 1. Similarly, when comparing the fourth REP (20 amino acid residues) with the fifth REP (30 amino acid residues), the ratio of the number of amino acid residues of the fifth REP is 30 / 20=1.5 when the number of amino acid residues of the fourth REP with fewer amino acid residues is set as 1.

[0126] In FIG. 1, when the number of amino acid residues of the one with fewer amino acid residues is set to 1, the ratio of the number of amino acid residues of the other one is 1.8 to 11.3 [(A) n The combination of motif-REP] units is shown by a solid line. In this specification, this ratio is called the "Jagged ratio." When the one with the fewer amino acid residues is set to 1, the ratio of the other amino acid residue number is less than 1.8 or more than 11.3 [(A) n The motif-REP] unit pairs are indicated by dashed lines.

[0127] In each pattern, the two adjacent [(A) nThe numbers of all amino acid residues in the motif-REP unit are added together (not only the numbers of amino acid residues in REP, but also in the (A)n motif). The sums are then compared, and the sum of the pattern with the largest sum (the maximum sum) is designated as x. In the example shown in Figure 1, the sum of pattern 1 is the largest.

[0128] Next, x / y (%) can be calculated by dividing x by the total number of amino acid residues, y, in the domain sequence.

[0129] In the third modified fibroin, x / y is preferably 50% or more, more preferably 60% or more, even more preferably 65% ​​or more, even more preferably 70% or more, even more preferably 75% or more, and particularly preferably 80% or more. There is no particular upper limit for x / y, and it may be, for example, 100% or less. When the knurling ratio is 1:1.9 to 11.3, x / y is preferably 89.6% or more, when the knurling ratio is 1:1.8 to 3.4, x / y is preferably 77.1% or more, when the knurling ratio is 1:1.9 to 8.4, x / y is preferably 75.9% or more, and when the knurling ratio is 1:1.9 to 4.1, x / y is preferably 64.2% or more.

[0130] The third modified fibroin is present multiple times in the domain sequence (A). n In the case of a modified fibroin in which at least seven of the motifs are composed only of alanine residues, x / y is preferably 46.4% or more, more preferably 50% or more, even more preferably 55% or more, even more preferably 60% or more, even more preferably 70% or more, and particularly preferably 80% or more. There is no particular upper limit to x / y, and it is sufficient as long as it is 100% or less.

[0131] Here, we will explain the x / y ratio of naturally occurring fibroin. First, as mentioned above, NCBI When fibroins with amino acid sequence information registered in GenBank were identified using the method described above, 663 types of fibroins (of which 415 were spider-derived fibroins) were extracted. Of all the extracted fibroins, those with the formula 1: [(A) n Motif-REP] m The ratio x / y was calculated by the above-mentioned calculation method from the amino acid sequence of naturally-occurring fibroin composed of the domain sequence represented by the following formula: The results when the jaggedness ratio was 1:1.9 to 4.1 are shown in FIG.

[0132] The horizontal axis of Fig. 3 indicates x / y (%), and the vertical axis indicates frequency. As is clear from Fig. 3, the x / y ratio in all naturally derived fibroins is less than 64.2% (the highest was 64.14%).

[0133] The third modified fibroin is, for example, (A) such that x / y is 64.2% or more based on the gene sequence of a cloned naturally occurring fibroin. n For example, one or more of the sequences encoding the motifs (A) may be deleted from the amino acid sequence of naturally occurring fibroin such that x / y is 64.2% or more. n Alternatively, the amino acid sequence corresponding to the deletion of the motif may be designed and a nucleic acid encoding the designed amino acid sequence may be chemically synthesized. In either case, the amino acid sequence of the naturally occurring fibroin may be selected from (A) n In addition to modifications corresponding to the deletion of a motif, further modifications to the amino acid sequence corresponding to the substitution, deletion, insertion and / or addition of one or more amino acid residues may be made.

[0134] More specific examples of the third modified fibroin include (3-i) a modified fibroin comprising an amino acid sequence shown in SEQ ID NO: 17 (Met-PRT399), SEQ ID NO: 7 (Met-PRT410), SEQ ID NO: 8 (Met-PRT525) or SEQ ID NO: 9 (Met-PRT799), or (3-ii) an amino acid sequence having 90% or more sequence identity to the amino acid sequence shown in SEQ ID NO: 17, SEQ ID NO: 7, SEQ ID NO: 8 or SEQ ID NO: 9.

[0135] The modified fibroin (3-i) will be described. The amino acid sequence shown in SEQ ID NO: 17 is a sequence of the amino acid sequence shown in SEQ ID NO: 10 (Met-PRT313) corresponding to naturally-occurring fibroin, which is obtained by subtracting every third amino acid from the N-terminus to the C-terminus. n The motif was deleted, and the C-terminal sequence was further amplified with [(A) n The amino acid sequence shown in SEQ ID NO: 7, SEQ ID NO: 8, or SEQ ID NO: 9 is as described for the second modified fibroin.

[0136] The value of x / y in the jagged ratio of 1:1.8-11.3 of the amino acid sequence shown in SEQ ID NO:10 (corresponding to naturally derived fibroin) is 15.0%. The values ​​of x / y in the amino acid sequence shown in SEQ ID NO:17 and the amino acid sequence shown in SEQ ID NO:7 are both 93.4%. The value of x / y in the amino acid sequence shown in SEQ ID NO:8 is 92.7%. The value of x / y in the amino acid sequence shown in SEQ ID NO:9 is 89.8%. The values ​​of z / w in the amino acid sequences shown in SEQ ID NO:10, SEQ ID NO:17, SEQ ID NO:7, SEQ ID NO:8 and SEQ ID NO:9 are 46.8%, 56.2%, 70.1%, 66.1% and 70.0%, respectively.

[0137] The modified fibroin (3-i) may consist of the amino acid sequence shown in SEQ ID NO: 17, SEQ ID NO: 7, SEQ ID NO: 8 or SEQ ID NO: 9.

[0138] The modified fibroin of (3-ii) contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 17, SEQ ID NO: 7, SEQ ID NO: 8 or SEQ ID NO: 9. The modified fibroin of (3-ii) also ... n Motif-REP] m It is a protein comprising a domain sequence represented by the following formula: The sequence identity is preferably 95% or more.

[0139] The modified fibroin (3-ii) has a sequence identity of 90% or more with the amino acid sequence shown in SEQ ID NO: 17, SEQ ID NO: 7, SEQ ID NO: 8 or SEQ ID NO: 9, and has two adjacent amino acids [(A) n The number of amino acid residues in the REP of the motif-REP] unit is compared in sequence. When the number of amino acid residues in the REP with the fewer amino acid residues is set to 1, the ratio of the number of amino acid residues in the other REP is 1.8 to 11.3 (the jagged ratio is 1:1.8 to 11.3) between two adjacent [(A) n When the maximum sum of the numbers of amino acid residues in the motif-REP units is x and the total number of amino acid residues in the domain sequence is y, it is preferable that x / y is 64.2% or more.

[0140] The third modified fibroin may contain the above-mentioned tag sequence at either or both of the N-terminus and C-terminus.

[0141] More specific examples of modified fibroins containing a tag sequence include (3-iii) modified fibroins containing an amino acid sequence shown in SEQ ID NO: 18 (PRT399), SEQ ID NO: 13 (PRT410), SEQ ID NO: 14 (PRT525) or SEQ ID NO: 15 (PRT799), or (3-iv) an amino acid sequence having 90% or more sequence identity to the amino acid sequence shown in SEQ ID NO: 18, SEQ ID NO: 13, SEQ ID NO: 14 or SEQ ID NO: 15.

[0142] The amino acid sequences shown in SEQ ID NO:18, SEQ ID NO:13, SEQ ID NO:14 and SEQ ID NO:15 are obtained by adding the amino acid sequence shown in SEQ ID NO:11 (including a His tag sequence and a hinge sequence) to the N-terminus of the amino acid sequences shown in SEQ ID NO:17, SEQ ID NO:7, SEQ ID NO:8 and SEQ ID NO:9, respectively.

[0143] The modified fibroin (3-iii) may consist of the amino acid sequence shown in SEQ ID NO:18, SEQ ID NO:13, SEQ ID NO:14 or SEQ ID NO:15.

[0144] The modified fibroin of (3-iv) contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 18, SEQ ID NO: 13, SEQ ID NO: 14, or SEQ ID NO: 15. The modified fibroin of (3-iv) also ... n Motif-REP] m It is a protein comprising a domain sequence represented by the following formula: The sequence identity is preferably 95% or more.

[0145] The modified fibroin (3-iv) has a sequence identity of 90% or more with the amino acid sequence shown in SEQ ID NO: 18, SEQ ID NO: 13, SEQ ID NO: 14, or SEQ ID NO: 15, and has two adjacent amino acids [(A) n The number of amino acid residues in the REP of the motif-REP] unit is compared in sequence. When the number of amino acid residues in the REP with the smaller number of amino acid residues is set to 1, the ratio of the number of amino acid residues in the other REP is 1.8 to 11.3 in two adjacent [(A) n When the maximum sum of the numbers of amino acid residues in the motif-REP units is x and the total number of amino acid residues in the domain sequence is y, it is preferable that x / y is 64.2% or more.

[0146] The third modified fibroin may contain a secretion signal for releasing the protein produced in the recombinant protein production system to the outside of the host. The sequence of the secretion signal can be appropriately set depending on the type of the host.

[0147] The fourth modified fibroin has a domain sequence different from that of naturally occurring fibroin, as follows: (A) n In addition to the reduced content of the motif, the fourth modified fibroin has an amino acid sequence with a reduced content of glycine residues. The fourth modified fibroin domain sequence has at least one or more (A) n In addition to the deletion of the motif, the fourth modified fibroin has an amino acid sequence in which at least one or more glycine residues in REP have been replaced with another amino acid residue. That is, the fourth modified fibroin is a modified fibroin having both the characteristics of the second modified fibroin and the third modified fibroin described above. Specific aspects are as described for the second modified fibroin and the third modified fibroin.

[0148] More specific examples of the fourth modified fibroin include (4-i) modified fibroin containing an amino acid sequence shown in SEQ ID NO: 7 (Met-PRT410), SEQ ID NO: 8 (Met-PRT525), SEQ ID NO: 9 (Met-PRT799), SEQ ID NO: 13 (PRT410), SEQ ID NO: 14 (PRT525) or SEQ ID NO: 15 (PRT799), or (4-ii) modified fibroin containing an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 13, SEQ ID NO: 14 or SEQ ID NO: 15. Specific embodiments of modified fibroin containing the amino acid sequence shown in SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 13, SEQ ID NO: 14 or SEQ ID NO: 15 are as described above.

[0149] The fifth modified fibroin may have an amino acid sequence whose domain sequence includes a localized region of high hydrophobicity index, corresponding to the replacement of one or more amino acid residues in REP with amino acid residues with a high hydrophobicity index and / or the insertion of one or more amino acid residues with a high hydrophobicity index into REP, compared to naturally occurring fibroin.

[0150] The region with a locally high hydrophobicity index is preferably composed of 2 to 4 consecutive amino acid residues.

[0151] The amino acid residue with a high hydrophobicity index is more preferably an amino acid residue selected from isoleucine (I), valine (V), leucine (L), phenylalanine (F), cysteine ​​(C), methionine (M) and alanine (A).

[0152] The fifth modified fibroin may, in addition to modifications corresponding to the replacement of one or more amino acid residues in REP with amino acid residues having a high hydrophobicity index and / or the insertion of one or more amino acid residues having a high hydrophobicity index into REP, have further modifications in the amino acid sequence corresponding to the substitution, deletion, insertion and / or addition of one or more amino acid residues compared to the naturally occurring fibroin.

[0153] The fifth modified fibroin can be obtained, for example, by substituting one or more hydrophilic amino acid residues (e.g., amino acid residues with a negative hydrophobicity index) in REP from the gene sequence of cloned naturally-derived fibroin with hydrophobic amino acid residues (e.g., amino acid residues with a positive hydrophobicity index) and / or by inserting one or more hydrophobic amino acid residues into REP. Alternatively, for example, it can be obtained by designing an amino acid sequence corresponding to the substitution of one or more hydrophilic amino acid residues in REP with hydrophobic amino acid residues from the amino acid sequence of naturally-derived fibroin and / or the insertion of one or more hydrophobic amino acid residues into REP, and chemically synthesizing a nucleic acid encoding the designed amino acid sequence. In either case, in addition to the modification corresponding to the substitution of one or more hydrophilic amino acid residues in REP with hydrophobic amino acid residues from the amino acid sequence of naturally-derived fibroin and / or the insertion of one or more hydrophobic amino acid residues into REP, the amino acid sequence may be modified by further substituting, deleting, inserting and / or adding one or more amino acid residues.

[0154] The fifth modified fibroin has the formula 1: [(A) n Motif-REP] m and (A) is located at the most C-terminal end. n In all REPs contained in the sequence excluding the sequence from the motif to the C-terminus of the domain sequence from the domain sequence, the total number of amino acid residues contained in a region in which the average hydrophobicity index of four consecutive amino acid residues is 2.6 or more is defined as p, and the region located most C-terminally is defined as (A). n The domain may have an amino acid sequence in which p / q is 6.2% or more, where q is the total number of amino acid residues contained in the domain sequence excluding the sequence from the motif to the C-terminus of the domain sequence.

[0155] The hydrophobicity index of amino acid residues is based on known indices (Hydropathy index: Kyte J, & Doolittle R (1982) “A simple method for displaying the hydropathic character of a protein”, J. Mol. Biol., 157, pp. 105-132) is used. Specifically, the hydrophobicity index (hereinafter also referred to as “HI”) of each amino acid is as shown in Table 1 below.

[0156] [Table 1]

[0157] The method of calculating p / q will be described in more detail. The calculation is carried out using the formula 1: [(A) n Motif-REP] m (A) is located at the C-terminal end of the domain sequence represented by nA sequence excluding the sequence from the motif to the C-terminus of the domain sequence (hereinafter referred to as "sequence A") is used. First, the average value of the hydrophobicity index of four consecutive amino acid residues is calculated for all REPs included in sequence A. The average value of the hydrophobicity index is calculated by dividing the sum of the HI of each amino acid residue included in the four consecutive amino acid residues by 4 (the number of amino acid residues). The average value of the hydrophobicity index is calculated for all four consecutive amino acid residues (each amino acid residue is used to calculate the average value 1 to 4 times). Next, a region in which the average value of the hydrophobicity index of the four consecutive amino acid residues is 2.6 or more is specified. Even if a certain amino acid residue corresponds to a plurality of "four consecutive amino acid residues with an average value of the hydrophobicity index of 2.6 or more", it is included as one amino acid residue in the region. The total number of amino acid residues included in the region is p. The total number of amino acid residues included in sequence A is q.

[0158] For example, if 20 "4 consecutive amino acid residues with an average hydrophobicity index of 2.6 or more" are extracted (without overlaps), the region in which the average hydrophobicity index of the consecutive 4 amino acid residues is 2.6 or more will contain 20 consecutive 4 amino acid residues (without overlaps), and p is 20×4=80. Also, for example, if two "4 consecutive amino acid residues with an average hydrophobicity index of 2.6 or more" overlap by one amino acid residue, the region in which the average hydrophobicity index of the consecutive 4 amino acid residues is 2.6 or more will contain 7 amino acid residues (p=2×4-1=7, where "-1" is the deduction of the overlap). For example, in the case of the domain sequence shown in FIG. 4, there are 7 "4 consecutive amino acid residues with an average hydrophobicity index of 2.6 or more" without overlaps, and p is 7×4=28. For example, in the case of the domain sequence shown in FIG. 4, q is 4+50+4+40+4+10+4+20+4+30=170 ((A) at the end of the C-terminus). n (The motif is not included.) Next, p / q (%) can be calculated by dividing p by q. In the case of Figure 4, it is 28 / 170 = 16.47%.

[0159] In the fifth modified fibroin, p / q is preferably 6.2% or more, more preferably 7% or more, even more preferably 10% or more, even more preferably 20% or more, and even more preferably 30% or more. The upper limit of p / q is not particularly limited, but may be, for example, 45% or less.

[0160] The fifth modified fibroin can be obtained, for example, by modifying the amino acid sequence of a cloned naturally-derived fibroin to include a region with a high hydrophobic index locally by substituting one or more hydrophilic amino acid residues (e.g., amino acid residues with a negative hydrophobic index) in the REP with hydrophobic amino acid residues (e.g., amino acid residues with a positive hydrophobic index) and / or inserting one or more hydrophobic amino acid residues into the REP so as to satisfy the above-mentioned p / q condition. Alternatively, for example, the fifth modified fibroin can be obtained by designing an amino acid sequence that satisfies the above-mentioned p / q condition from the amino acid sequence of a naturally-derived fibroin and chemically synthesizing a nucleic acid encoding the designed amino acid sequence. In either case, in addition to the modification corresponding to the substitution of one or more amino acid residues in the REP with amino acid residues with a high hydrophobic index and / or the insertion of one or more amino acid residues with a high hydrophobic index into the REP, modifications corresponding to the substitution, deletion, insertion and / or addition of one or more amino acid residues may be performed.

[0161] The amino acid residues having a high hydrophobicity index are not particularly limited, but are preferably isoleucine (I), valine (V), leucine (L), phenylalanine (F), cysteine ​​(C), methionine (M) and alanine (A), and more preferably valine (V), leucine (L) and isoleucine (I).

[0162] A more specific example of the fifth modified fibroin includes (5-i) a modified fibroin comprising an amino acid sequence shown in SEQ ID NO: 19 (Met-PRT720), SEQ ID NO: 20 (Met-PRT665) or SEQ ID NO: 21 (Met-PRT666), or (5-ii) an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 19, SEQ ID NO: 20 or SEQ ID NO: 21.

[0163] The modified fibroin of (5-i) will be described. The amino acid sequence shown in SEQ ID NO: 19 is obtained by inserting an amino acid sequence (VLI) consisting of three amino acid residues at every other REP at two positions, excluding the domain sequence at the C-terminus, and further substituting some glutamine (Q) residues with serine (S) residues, and deleting some amino acids at the C-terminus, in the amino acid sequence shown in SEQ ID NO: 7 (Met-PRT410). The amino acid sequence shown in SEQ ID NO: 20 is obtained by inserting an amino acid sequence (VLI) consisting of three amino acid residues at every other REP at one position, in the amino acid sequence shown in SEQ ID NO: 8 (Met-PRT525). The amino acid sequence shown in SEQ ID NO: 21 is obtained by inserting an amino acid sequence (VLI) consisting of three amino acid residues at every other REP at two positions, in the amino acid sequence shown in SEQ ID NO: 8.

[0164] The modified fibroin (5-i) may consist of the amino acid sequence shown in SEQ ID NO:19, SEQ ID NO:20 or SEQ ID NO:21.

[0165] The modified fibroin of (5-ii) contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 19, SEQ ID NO: 20, or SEQ ID NO: 21. The modified fibroin of (5-ii) also contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 19, SEQ ID NO: 20, or SEQ ID NO: 21. The modified fibroin of n Motif-REP] m It is a protein comprising a domain sequence represented by the following formula: The sequence identity is preferably 95% or more.

[0166] The modified fibroin (5-ii) has a sequence identity of 90% or more with the amino acid sequence shown in SEQ ID NO: 19, SEQ ID NO: 20, or SEQ ID NO: 21 and is located at the most C-terminal side (A). n In all REPs contained in the sequence excluding the sequence from the motif to the C-terminus of the domain sequence from the domain sequence, the total number of amino acid residues contained in the region in which the average hydrophobicity index of four consecutive amino acid residues is 2.6 or more is defined as p, and the region located most C-terminally is defined as (A). n When the total number of amino acid residues contained in the sequence excluding the sequence from the motif to the C-terminus of the domain sequence is defined as q, it is preferable that p / q is 6.2% or more.

[0167] The fifth modified fibroin may contain a tag sequence at either or both of the N-terminus and C-terminus.

[0168] More specific examples of modified fibroins containing a tag sequence include (5-iii) modified fibroins containing an amino acid sequence shown in SEQ ID NO: 22 (PRT720), SEQ ID NO: 23 (PRT665) or SEQ ID NO: 24 (PRT666), or (5-iv) an amino acid sequence having 90% or more sequence identity to the amino acid sequence shown in SEQ ID NO: 22, SEQ ID NO: 23 or SEQ ID NO: 24.

[0169] The amino acid sequences shown in SEQ ID NO: 22, SEQ ID NO: 23 and SEQ ID NO: 24 are obtained by adding the amino acid sequence shown in SEQ ID NO: 11 (including the His tag sequence and hinge sequence) to the N-terminus of the amino acid sequences shown in SEQ ID NO: 19, SEQ ID NO: 20 and SEQ ID NO: 21, respectively.

[0170] The modified fibroin (5-iii) may consist of the amino acid sequence shown in SEQ ID NO:22, SEQ ID NO:23 or SEQ ID NO:24.

[0171] The modified fibroin (5-iv) contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 22, SEQ ID NO: 23, or SEQ ID NO: 24. The modified fibroin (5-iv) also ... n Motif-REP] m It is a protein comprising a domain sequence represented by the following formula: The sequence identity is preferably 95% or more.

[0172] The modified fibroin (5-iv) has a sequence identity of 90% or more with the amino acid sequence shown in SEQ ID NO: 22, SEQ ID NO: 23, or SEQ ID NO: 24 and is located at the most C-terminal side (A). n In all REPs contained in the sequence excluding the sequence from the motif to the C-terminus of the domain sequence from the domain sequence, the total number of amino acid residues contained in the region in which the average hydrophobicity index of four consecutive amino acid residues is 2.6 or more is defined as p, and the region located most C-terminally is defined as (A). n When the total number of amino acid residues contained in the sequence excluding the sequence from the motif to the C-terminus of the domain sequence is defined as q, it is preferable that p / q is 6.2% or more.

[0173] The fifth modified fibroin may contain a secretion signal for releasing the protein produced in the recombinant protein production system to the outside of the host. The sequence of the secretion signal can be appropriately set depending on the type of the host.

[0174] The sixth modified fibroin has an amino acid sequence with a reduced content of glutamine residues compared to naturally occurring fibroin.

[0175] It is preferable that the sixth modified fibroin contains at least one motif selected from the GGX motif and the GPGXX motif in the amino acid sequence of REP.

[0176] When the sixth modified fibroin contains a GPGXX motif in the REP, the GPGXX motif content is usually 1% or more, may be 5% or more, and is preferably 10% or more. There is no particular upper limit to the GPGXX motif content, and it may be 50% or less, or may be 30% or less.

[0177] As used herein, the "GPGXX motif content" is a value calculated by the following method. Formula 1:[(A) n Motif-REP] m Or formula 2: [(A) n Motif-REP] m -(A) n In a fibroin (modified fibroin or naturally-occurring fibroin) containing a domain sequence represented by the motif, (A) is located at the most C-terminal side. n For all REPs contained in the sequence excluding the sequence from the motif to the C-terminus of the domain sequence from the domain sequence, the total number of GPGXX motifs contained in that region is multiplied by three (i.e., the total number of G and P in the GPGXX motif), and the number s is the number located at the most C-terminus side (A). n The sequence from the motif to the C-terminus of the domain sequence is removed from the domain sequence, and further (A) n When the total number of amino acid residues of all REPs excluding the motif is t, the GPGXX motif content is calculated as s / t.

[0178] In calculating the GPGXX motif content, the most C-terminal (A) n The target sequence is the sequence excluding the sequence from the motif to the C-terminus of the domain sequence, which is the sequence located at the most C-terminus (A). nThe "sequence from the motif to the C-terminus of the domain sequence" (sequence corresponding to REP) may contain sequences with low correlation with sequences characteristic of fibroin, and when m is small (i.e., when the domain sequence is short), this affects the calculation results of the GPGXX motif content, so this is to eliminate this influence. Note that when the "GPGXX motif" is located at the C-terminus of REP, even if "XX" is, for example, "AA", it is treated as a "GPGXX motif".

[0179] FIG. 5 is a schematic diagram showing the domain sequence of a modified fibroin. A method for calculating the GPGXX motif content will be specifically described with reference to FIG. 5. First, the domain sequence of the modified fibroin shown in FIG. n Motif-REP] m -(A) n In the 1990s, all REPs were located at the C-terminus (A) n Since the number of GPGXX motifs is 7, s is 7 × 3 = 21. Similarly, all REPs are included in the "domain sequence excluding the sequence from the motif to the C-terminus of the domain sequence" (the sequence shown as "Region A" in Figure 5). n Since the domain sequence is excluded from the sequence from the motif to the C-terminus of the domain sequence (the sequence shown as "Region A" in Figure 5), the sequence is further divided into (A) n The total number of amino acid residues of all REPs excluding motifs, t, is 50 + 40 + 10 + 20 + 30 = 150. Next, s / t (%) can be calculated by dividing s by t, which is 21 / 150 = 14.0% in the case of the modified fibroin in Figure 5.

[0180] The sixth modified fibroin preferably has a glutamine residue content of 9% or less, more preferably 7% or less, even more preferably 4% or less, and particularly preferably 0%.

[0181] In this specification, the "glutamine residue content" is a value calculated by the following method. Formula 1:[(A) n Motif-REP] m Or formula 2: [(A) n Motif-REP] m -(A) n In a fibroin (modified fibroin or naturally-occurring fibroin) containing a domain sequence represented by the motif, (A) is located at the most C-terminal side. n In all REPs contained in the sequence obtained by removing the sequence from the motif to the C-terminus of the domain sequence (the sequence corresponding to "Region A" in Figure 5), the total number of glutamine residues contained in the region is defined as u, and the number of glutamine residues located most C-terminally is defined as (A). n The sequence from the motif to the C-terminus of the domain sequence is removed from the domain sequence, and further (A) n When the total number of amino acid residues of all REPs excluding the motif is t, the glutamine residue content is calculated as u / t. n The reason for targeting "the sequence obtained by excluding the sequence from the motif to the C-terminus of the domain sequence from the domain sequence" is the same as that mentioned above.

[0182] The sixth modified fibroin may have an amino acid sequence whose domain sequence corresponds to the deletion of one or more glutamine residues in the REP or the substitution of other amino acid residues, compared to a naturally occurring fibroin.

[0183] The "other amino acid residue" may be any amino acid residue other than glutamine residue, but is preferably an amino acid residue with a higher hydrophobicity index than glutamine residue. The hydrophobicity indexes of amino acid residues are as shown in Table 1.

[0184] As shown in Table 1, examples of amino acid residues having a higher hydrophobicity index than glutamine residues include amino acid residues selected from isoleucine (I), valine (V), leucine (L), phenylalanine (F), cysteine ​​(C), methionine (M), alanine (A), glycine (G), threonine (T), serine (S), tryptophan (W), tyrosine (Y), proline (P) and histidine (H). Among these, amino acid residues selected from isoleucine (I), valine (V), leucine (L), phenylalanine (F), cysteine ​​(C), methionine (M) and alanine (A) are more preferred, and amino acid residues selected from isoleucine (I), valine (V), leucine (L) and phenylalanine (F) are even more preferred.

[0185] In the sixth modified fibroin, the hydrophobicity of REP is preferably -0.8 or more, more preferably -0.7 or more, even more preferably 0 or more, even more preferably 0.3 or more, and particularly preferably 0.4 or more. There is no particular upper limit to the hydrophobicity of REP, and it may be 1.0 or less, or 0.7 or less.

[0186] In this specification, the "hydrophobicity of REP" is a value calculated by the following method. Formula 1:[(A) n Motif-REP] m Or formula 2: [(A) n Motif-REP] m -(A) n In a fibroin (modified fibroin or naturally-occurring fibroin) containing a domain sequence represented by the motif, (A) is located at the most C-terminal side. n For all REPs contained in the sequence obtained by removing the sequence from the motif to the C-terminus of the domain sequence (the sequence corresponding to "Region A" in Figure 5), the sum of the hydrophobicity indexes of each amino acid residue in that region is v, and the REP located at the most C-terminus side (A) n The sequence from the motif to the C-terminus of the domain sequence is removed from the domain sequence, and further (A) nWhen the total number of amino acid residues of all REPs excluding the motif is t, the hydrophobicity of the REP is calculated as v / t. n The reason for targeting "the sequence obtained by excluding the sequence from the motif to the C-terminus of the domain sequence from the domain sequence" is the same as that mentioned above.

[0187] The sixth modified fibroin may have a domain sequence that, compared to a naturally occurring fibroin, is modified by the deletion of one or more glutamine residues in the REP and / or the replacement of one or more glutamine residues in the REP with other amino acid residues, and may also have an amino acid sequence modification that is equivalent to the substitution, deletion, insertion and / or addition of one or more amino acid residues.

[0188] The sixth modified fibroin can be obtained, for example, by deleting one or more glutamine residues in REP from the gene sequence of a cloned naturally-occurring fibroin and / or substituting one or more glutamine residues in REP with other amino acid residues. It can also be obtained, for example, by designing an amino acid sequence corresponding to the deletion of one or more glutamine residues in REP from the amino acid sequence of a naturally-occurring fibroin and / or the substitution of one or more glutamine residues in REP with other amino acid residues, and chemically synthesizing a nucleic acid encoding the designed amino acid sequence.

[0189] More specific examples of the sixth modified fibroin include (6-i) modified fibroin having an amino acid sequence shown in SEQ ID NO: 25 (Met-PRT888), SEQ ID NO: 26 (Met-PRT965), SEQ ID NO: 27 (Met-PRT889), SEQ ID NO: 28 (Met-PRT916), SEQ ID NO: 29 (Met-PRT918), SEQ ID NO: 30 (Met-PRT699), SEQ ID NO: 31 (Met-PRT698), SEQ ID NO: 32 (Met-PRT966), SEQ ID NO: 41 (Met-PRT917) or SEQ ID NO: 42 (Met-PRT1028), or (6-ii) modified fibroin having an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 32, SEQ ID NO: 41 or SEQ ID NO: 42.

[0190] The modified fibroin (6-i) will be described. The amino acid sequence shown in SEQ ID NO: 25 is obtained by substituting all QQ in the amino acid sequence shown in SEQ ID NO: 7 (Met-PRT410) with VL. The amino acid sequence shown in SEQ ID NO: 26 is obtained by substituting all QQ in the amino acid sequence shown in SEQ ID NO: 7 with TS, and substituting the remaining Q with A. The amino acid sequence shown in SEQ ID NO: 27 is obtained by substituting all QQ in the amino acid sequence shown in SEQ ID NO: 7 with VL, and substituting the remaining Q with I. The amino acid sequence shown in SEQ ID NO: 28 is obtained by substituting all QQ in the amino acid sequence shown in SEQ ID NO: 7 with VI, and substituting the remaining Q with L. The amino acid sequence shown in SEQ ID NO: 29 is obtained by substituting all QQ in the amino acid sequence shown in SEQ ID NO: 7 with VF, and substituting the remaining Q with I.

[0191] The amino acid sequence shown in SEQ ID NO: 30 is the amino acid sequence shown in SEQ ID NO: 8 (Met-PRT525) in which all QQ are replaced with VL. The amino acid sequence shown in SEQ ID NO: 31 is the amino acid sequence shown in SEQ ID NO: 8 in which all QQ are replaced with VL and the remaining Q is replaced with I.

[0192] The amino acid sequence shown in SEQ ID NO:32 is a sequence in which the 20 domain sequence region present in the amino acid sequence shown in SEQ ID NO:7 (Met-PRT410) is repeated twice, with all QQs replaced with VF and the remaining Qs replaced with I.

[0193] The amino acid sequence shown in SEQ ID NO:41 (Met-PRT917) is obtained by replacing all QQ in the amino acid sequence shown in SEQ ID NO:7 with LI and the remaining Q with V. The amino acid sequence shown in SEQ ID NO:42 (Met-PRT1028) is obtained by replacing all QQ in the amino acid sequence shown in SEQ ID NO:7 with IF and the remaining Q with T.

[0194] The amino acid sequences shown in SEQ ID NO:25, SEQ ID NO:26, SEQ ID NO:27, SEQ ID NO:28, SEQ ID NO:29, SEQ ID NO:30, SEQ ID NO:31, SEQ ID NO:32, SEQ ID NO:41 and SEQ ID NO:42 all have a glutamine residue content of 9% or less (Table 2).

[0195] [Table 2]

[0196] The modified fibroin (6-i) may consist of the amino acid sequence shown in SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 32, SEQ ID NO: 41 or SEQ ID NO: 42.

[0197] The modified fibroin of (6-ii) contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 32, SEQ ID NO: 41, or SEQ ID NO: 42. The modified fibroin of (6-ii) also contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 32, SEQ ID NO: 41, or SEQ ID NO: 42. The modified fibroin of (6 n Motif-REP] m Or formula 2: [(A) n Motif-REP] m -(A) nIt is a protein containing a domain sequence represented by the motif. The sequence identity is preferably 95% or more.

[0198] The modified fibroin (6-ii) preferably has a glutamine residue content of 9% or less, and the modified fibroin (6-ii) preferably has a GPGXX motif content of 10% or more.

[0199] The sixth modified fibroin may contain a tag sequence at either or both of the N-terminus and C-terminus, which allows the modified fibroin to be isolated, immobilized, detected, visualized, and the like.

[0200] More specific examples of modified fibroins containing a tag sequence include (6-iii) modified fibroins containing the amino acid sequence shown in SEQ ID NO: 33 (PRT888), SEQ ID NO: 34 (PRT965), SEQ ID NO: 35 (PRT889), SEQ ID NO: 36 (PRT916), SEQ ID NO: 37 (PRT918), SEQ ID NO: 38 (PRT699), SEQ ID NO: 39 (PRT698), SEQ ID NO: 40 (PRT966), SEQ ID NO: 43 (PRT917) or SEQ ID NO: 44 (PRT1028), or (6-iv) modified fibroins containing an amino acid sequence having 90% or more sequence identity to the amino acid sequence shown in SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 43 or SEQ ID NO: 44.

[0201] The amino acid sequences shown in SEQ ID NO:33, SEQ ID NO:34, SEQ ID NO:35, SEQ ID NO:36, SEQ ID NO:37, SEQ ID NO:38, SEQ ID NO:39, SEQ ID NO:40, SEQ ID NO:43 and SEQ ID NO:44 are obtained by adding the amino acid sequence shown in SEQ ID NO:11 (including a His tag sequence and a hinge sequence) to the N-terminus of the amino acid sequences shown in SEQ ID NO:25, SEQ ID NO:26, SEQ ID NO:27, SEQ ID NO:28, SEQ ID NO:29, SEQ ID NO:30, SEQ ID NO:31, SEQ ID NO:32, SEQ ID NO:41 and SEQ ID NO:42, respectively. Since only a tag sequence is added to the N-terminus, there is no change in the glutamine residue content, and the amino acid sequences shown in SEQ ID NO:33, SEQ ID NO:34, SEQ ID NO:35, SEQ ID NO:36, SEQ ID NO:37, SEQ ID NO:38, SEQ ID NO:39, SEQ ID NO:40, SEQ ID NO:43 and SEQ ID NO:44 all have a glutamine residue content of 9% or less (Table 3).

[0202] [Table 3]

[0203] The modified fibroin (6-iii) may consist of the amino acid sequence shown in SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 43 or SEQ ID NO: 44.

[0204] The modified fibroin of (6-iv) contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 43, or SEQ ID NO: 44. The modified fibroin of (6-iv) also contains an amino acid sequence having 90% or more sequence identity with the amino acid sequence shown in SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 43, or SEQ ID NO: 44. The modified fibroin of (6 n Motif-REP] m Or formula 2: [(A) n Motif-REP] m -(A) n It is a protein containing a domain sequence represented by the motif. The sequence identity is preferably 95% or more.

[0205] The modified fibroin (6-iv) preferably has a glutamine residue content of 9% or less, and the modified fibroin (6-iv) preferably has a GPGXX motif content of 10% or more.

[0206] The sixth modified fibroin may contain a secretion signal for releasing the protein produced in the recombinant protein production system to the outside of the host. The sequence of the secretion signal can be appropriately selected depending on the type of the host.

[0207] The modified fibroin may be a modified fibroin having 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.

[0208] The modified fibroin may be either hydrophilic or hydrophobic. In this specification, the term "hydrophilic modified fibroin" refers to modified fibroin in which the sum of the hydrophobicity index (HI) of all amino acid residues constituting the modified fibroin is calculated and then the sum is divided by the total number of amino acid residues, resulting in an average HI of 0 or less. The hydrophobicity index is as shown in Table 1. The term "hydrophobic modified fibroin" refers to modified fibroin in which the average HI is greater than 0. The hydrophilic modified fibroin is particularly excellent in flame retardancy. The hydrophobic modified fibroin is particularly excellent in hygroscopic heat generation and heat retention.

[0209] Examples of hydrophilic modified fibroins include modified fibroins containing the amino acid sequence shown in SEQ ID NO:4, the amino acid sequence shown in SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8 or SEQ ID NO:9, the amino acid sequence shown in SEQ ID NO:13, SEQ ID NO:11, SEQ ID NO:14 or SEQ ID NO:15, the amino acid sequence shown in SEQ ID NO:18, SEQ ID NO:7, SEQ ID NO:8 or SEQ ID NO:9, the amino acid sequence shown in SEQ ID NO:17, SEQ ID NO:11, SEQ ID NO:14 or SEQ ID NO:15, the amino acid sequence shown in SEQ ID NO:19, SEQ ID NO:20 or SEQ ID NO:21.

[0210] Examples of hydrophobic modified fibroins include modified fibroins having the amino acid sequence shown in SEQ ID NO:27, SEQ ID NO:28, SEQ ID NO:29, SEQ ID NO:30, SEQ ID NO:31, SEQ ID NO:32, SEQ ID NO:33 or SEQ ID NO:43, SEQ ID NO:35, SEQ ID NO:37, SEQ ID NO:38, SEQ ID NO:39, SEQ ID NO:40, SEQ ID NO:41 or SEQ ID NO:44.

[0211] The modified fibroin according to the present embodiment can be produced by a conventional method using a nucleic acid encoding the modified fibroin. The nucleic acid encoding the modified fibroin may be chemically synthesized based on the base sequence information, or may be synthesized using a PCR method or the like.

[0212] Artificial protein fibers can be obtained, for example, by dissolving a protein in a solvent capable of dissolving the protein to prepare a dope solution, and spinning the solution using a known spinning method such as wet spinning, dry spinning, dry-wet spinning, or melt spinning. Examples of solvents capable of dissolving proteins include dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), formic acid, and hexafluoroisopropanol (HFIP). Inorganic salts may be added to the solvent as dissolution promoters.

[0213] (artificial fur) The artificial fur according to the present embodiment may contain fibers other than the artificial protein fibers, so long as the effects of the present invention are not impaired. Examples of the other fibers include synthetic fibers such as nylon, polyamide, polyester, polyacrylonitrile, polyolefin, polyvinyl alcohol, polyethylene terephthalate, polytetrafluoroethylene, and acrylic resin, regenerated fibers such as cupra, rayon, and lyocell, and natural fibers such as cotton, hemp cotton, silk, wool, and cashmere.

[0214] The artificial fur according to the present embodiment may further contain other components in addition to the fibers, such as colorants, smoothing agents, antioxidants, UV absorbers, dyes, fillers, crosslinking agents, matting agents, and leveling agents.

[0215] The artificial fur according to this embodiment may have a maximum moisture absorption heat generation rate calculated according to the following formula A of more than 0.025° C. / g. Formula A: Maximum moisture absorption heat release rate = {(Maximum sample temperature when the sample is placed in a low humidity environment until the sample temperature reaches equilibrium and then transferred to a high humidity environment) - (sample temperature when the sample is placed in a low humidity environment until the sample temperature reaches equilibrium and then transferred to a high humidity environment)} (°C) / sample weight (g) In formula A, the low humidity environment means an environment with a temperature of 20° C. and a relative humidity of 40%, and the high humidity environment means an environment with a temperature of 20° C. and a relative humidity of 90%.

[0216] The artificial fur according to this embodiment may have a maximum moisture absorption heat generation rate of 0.026° C. / g or more, 0.027° C. / g or more, 0.028° C. / g or more, 0.029° C. / g or more, 0.030° C. / g or more, 0.031° C. / g or more, 0.035° C. / g or more, or 0.040° C. / g or more. There is no particular upper limit to the maximum moisture absorption heat generation rate, but it is usually 0.060° C. / g or less.

[0217] The artificial fur according to the present embodiment may have a limiting oxygen index (LOI) value of 18.0 or more, 20.0 or more, 22.0 or more, 24.0 or more, 26.0 or more, 28.0 or more, 29.0 or more, or 30.0 or more. In this specification, the LOI value is determined by the Chief of the Hazardous Materials Regulation Division of the Fire and Disaster Management Agency. This value is measured in accordance with the test method for powdered or low-melting-point synthetic resins, Fire Prevention Hazard No. 50, issued on May 31, 1995.

[0218] The artificial fur according to this embodiment may have a heat retention index calculated according to the following formula B of more than 0.18. Formula B: Heat retention index = Heat retention rate (%) / Sample weight (g / m 2 ) In this specification, the heat retention rate means the heat retention rate measured by the dry contact method using a Thermo Labo II type testing machine (in a wind of 30 cm / sec), and is a value measured by the method described in the examples described below.

[0219] The thermal insulation index of the artificial fur according to the present embodiment may be 0.20 or more, 0.22 or more, 0.24 or more, 0.26 or more, 0.28 or more, 0.30 or more, or 0.32 or more. There is no particular upper limit to the thermal insulation index, but it may be, for example, 0.60 or less, or 0.40 or less.

[0220] (Manufacturing method of artificial fur) The artificial fur of this embodiment can be obtained, for example, by a method using the above-mentioned fibers (fibers including artificial protein fibers) and comprising a step of obtaining pile fabric having a large number of pile threads protruding from one or both sides of the fabric (pile fabric production step), a step of cutting (shearing) the pile loops to form cut pile (cut hair) (shearing step), and, if necessary, a step of combing the cut pile (cut hair) (combing step) and / or a step of washing the fabric on which the cut pile (cut hair) has been formed (washing step).

[0221] The pile fabric manufacturing process can be carried out, for example, according to a method such as pile weaving or pile knitting used in the manufacture of known pile fabrics such as woven pile fabrics and knitted pile fabrics. In the case of woven pile fabrics, the pile may be formed of warp yarns (warp pile weaving) or weft yarns (weft pile weaving). The size of the pile (loop) can be appropriately set depending on the application of the artificial fur, and may be, for example, 5 mm or more and 50 mm or less.

[0222] The shearing step can be carried out, for example, according to a method commonly used in the production of cut pile fabrics.

[0223] The fibers used in the manufacture of the artificial leather according to the present embodiment may contain artificial protein fibers, and the form of the yarn is not particularly limited. That is, for example, the fibers may be yarns made of bundled filaments, twisted yarns made by twisting bundles of such yarns, or spun yarns made of staples. The spun yarns may be yarns that have been spun, or may be twisted yarns that have been further twisted. These yarns are manufactured according to known methods. For example, the spun yarns can be obtained by a method including a step of spinning a fiber raw material according to a conventional method to obtain fibers (spinning step), a step of crimping the obtained fibers as necessary (scrimping step), a step of cutting the fibers to obtain staples (short fibers) (cutting step), a step of water treatment as necessary (water treatment step), a step of opening and / or defibrating the staples as necessary (opening step), and a step of spinning the staples (spinning step).

[0224] The spinning step can be carried out according to a conventional method. The spinning method may be any of wet spinning, dry spinning, dry-wet spinning, and melt spinning.

[0225] The crimping step may be carried out as necessary, and can be carried out, for example, by a mechanical crimping method such as a pressing method, or a method in which the staple is brought into contact with an aqueous medium to cause crimping (hereinafter sometimes referred to as "water crimping").

[0226] The aqueous medium is a liquid or gas (steam) medium containing water (including water vapor). The aqueous medium may be water or a mixture of water and a hydrophilic solvent. In addition, as the hydrophilic solvent, for example, a volatile solvent such as ethanol and methanol or its vapor can be used. 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. By using an aqueous medium containing a volatile solvent or its vapor, the drying speed after water crimping can be improved, and further, a soft texture may be imparted to the finally obtained crimped staple. The ratio of water to the volatile solvent or its vapor is not particularly limited, and for example, the water:volatile solvent or its vapor may be 10:90 to 90:10 in mass ratio. The proportion of water is preferably 30 mass% or more, and may be 40 mass% or 50 mass% or more.

[0227] 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, or 100° C. or lower.

[0228] The time for contacting with the aqueous medium is not particularly limited, but may be 30 seconds or more, 1 minute or more, or 2 minutes or more, and is preferably 10 minutes or less from the viewpoint of productivity. The contacting with the aqueous medium may be performed under normal pressure or under reduced pressure (e.g., vacuum).

[0229] Examples of the method of contacting the staple with the aqueous medium include a method of immersing the staple in the aqueous medium, a method of spraying the steam of the aqueous medium onto the staple, and a method of exposing the staple to an environment filled with the steam of the aqueous medium. When the aqueous medium is steam, the contact of the aqueous medium with the staple can be carried out using a general steam setting device. Specific examples of the steam setting device include devices such as FMSA type steam setter (manufactured by Fukushin Kogyo Co., Ltd.) and EPS-400 (manufactured by Tsujii Senki Kogyo Co., Ltd.). Specific examples of the method of crimping the staple with the steam of the aqueous medium include a method of placing the staple in a predetermined storage chamber, introducing the steam of the aqueous medium into the storage chamber, and contacting the steam with the staple while adjusting the temperature in the storage chamber to the above-mentioned predetermined temperature (for example, 100°C to 230°C).

[0230] After contacting the staple with the aqueous medium, it may be further dried. The drying method is not particularly limited, and the drying may be natural drying, or drying with hot air or a hot roller. The drying temperature is not particularly limited, and may be, for example, 20 to 150°C, preferably 40 to 120°C, and more preferably 60 to 100°C.

[0231] The cutting step can be carried out using any device capable of cutting fibers. For example, a tabletop fiber cutter (s / NO. IT-160201-NP-300) can be mentioned as such a device. The length of the staple is not particularly limited, but may be, for example, 20 mm or more, 20 to 140 mm, 70 to 140 mm, or 20 to 70 mm.

[0232] The water treatment step may be carried out as necessary, and may be carried out, for example, in the same manner as in the water crimping.

[0233] The opening step may be carried out as necessary, and may be carried out, for example, by opening or defibrating the staples with an opener or breaker.

[0234] The spinning step can be carried out by a known spinning method. Examples of the spinning method include cotton spinning, worsted spinning, and woolen spinning. The apparatus used for these spinning methods is not particularly limited, and commonly used apparatus can be used. The spun yarn may be a single yarn or a blended yarn such as a two-ply yarn (for example, a blended yarn of an artificial protein fiber and the above-mentioned other fibers).

[0235] <Second embodiment> The artificial fur according to the second embodiment of the second invention comprises shrink-proof protein fibers.

[0236] Protein fibers are fibers spun using proteins as the main raw material. Protein fibers can be obtained, for example, by dissolving a protein in a solvent capable of dissolving the protein to prepare a dope solution, and spinning the solution by a known spinning method such as wet spinning, dry spinning, dry-wet spinning, or melt spinning. Examples of solvents capable of dissolving proteins include dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), formic acid, and hexafluoroisopropanol (HFIP). Inorganic salts may be added to the solvent as a dissolution promoter.

[0237] Fig. 6 is an explanatory diagram that shows a schematic diagram of an example of a spinning apparatus for producing protein fibers. The spinning apparatus 1000 shown in Fig. 6 is an example of a spinning apparatus for dry / wet spinning, and includes an extrusion apparatus 101, an undrawn yarn producing apparatus 102, a wet heat drawing apparatus 103, and a drying apparatus 104.

[0238] A spinning method using the spinning apparatus 1000 will be described. First, the dope 106 stored in the storage tank 107 is extruded from the die 109 by the gear pump 108. In a laboratory scale, the dope may be filled in a cylinder and extruded from a nozzle using a syringe pump. Next, the extruded dope 106 is supplied to the coagulation liquid 111 in the coagulation liquid tank 120 through the air gap 119, the solvent is removed, the protein is coagulated, and a fibrous coagulate is formed. Next, the fibrous coagulate is supplied to the hot water 112 in the stretching bath 121 and stretched. The stretching ratio is determined by the speed ratio between the supply nip roller 113 and the take-up nip roller 114. Thereafter, the stretched fibrous coagulate is supplied to the drying device 104 and dried in the thread path 122, and the protein fiber 136 is obtained as the wound yarn 105. 118a to 118g are thread guides.

[0239] (Shrink-proofing treatment) Examples of methods for shrink-proofing protein fibers include a method in which protein fibers after spinning and before contact with water are brought into contact with water to irreversibly shrink them (water shrinkage method), and a method in which protein fibers after spinning and before contact with water are heated and the protein fibers in a heated state are relaxed and irreversibly shrink them (dry heat shrinkage method), etc. Both the water shrinkage method and the dry heat shrinkage method may be performed on protein fibers before they are woven into an artificial fur, or may be performed on the artificial fur after they are woven (either before or after the pile loops are cut).

[0240] The irreversible shrinkage of protein fibers is thought to occur for the following reasons, for example: One reason is thought to be due to the secondary or tertiary structure of the protein fibers, and another reason is thought to occur when, for example, in protein fibers having residual stress due to stretching or the like in the production process, the residual stress is relaxed.

[0241] The water shrinking method includes a step (shrinking step) of contacting the protein fibers with water after spinning and before contacting with water to irreversibly shrink them. In the shrinking step, the protein fibers shrink due to contact with water without external force. The water to be contacted may be in either liquid or gaseous state. The method of contacting the protein fibers with water is also not particularly limited, and examples thereof include a method of immersing the protein fibers in water, a method of spraying water at room temperature or in the form of heated steam or the like onto the protein fibers, and a method of exposing the protein fibers to a high humidity environment filled with water vapor. Among these methods, the method of immersing the protein fibers in water is preferred because it can effectively shorten the shrinkage time and can simplify the processing equipment. Specific examples of the method of immersing the protein fibers in water include a method of putting the protein fibers (or artificial fur) into a container containing water at a predetermined temperature and contacting the protein fibers with water.

[0242] The temperature of the water brought into contact with the protein fibers is not particularly limited, but is preferably, for example, below the boiling point. Such a temperature improves handling and workability in the shrinking step. The upper limit of the water temperature is preferably 90°C or lower, and more preferably 80°C or lower. The lower limit of the water temperature is preferably 10°C or higher, more preferably 40°C or higher, and even more preferably 70°C or higher. The temperature of the water brought into contact with the protein fibers can be adjusted depending on the fibers that make up the protein fibers. The temperature of the water may be constant while the water is in contact with the protein fibers, or the temperature of the water may be adjusted to a desired value. The temperature may be varied to a constant value.

[0243] The time for contacting the protein fibers with water is not particularly limited and may be, for example, 1 minute or more. The time may be 10 minutes or more, 20 minutes or more, or 30 minutes or more. There is no particular upper limit to the time, but from the viewpoint of shortening the production process time and eliminating the risk of hydrolysis of the protein fibers, it may be, for example, 120 minutes or less, 90 minutes or less, or 60 minutes or less.

[0244] The water shrinkage method may further include, following the shrinkage step, a step of contacting the protein fibers with water and then drying them (drying step).

[0245] The drying method in the drying step is not particularly limited, and may be, for example, natural drying or forced drying using drying equipment. The drying temperature is not particularly limited as long as it is lower than the temperature at which the protein is thermally damaged, but is generally within the range of 20 to 150°C, preferably within the range of 40 to 120°C, and more preferably within the range of 60 to 100°C. Within such a temperature range, the protein fiber can be dried more quickly and efficiently without causing thermal damage to the protein. The drying time is appropriately selected depending on the drying temperature, etc., and may be, for example, 10 minutes. The time period adopted is such that the influence of excessive drying of protein fibers on the quality and physical properties of the woven fabric can be eliminated.

[0246] The dry heat shrinkage method includes a step of heating the protein fibers after spinning and before they come into contact with water (heating step), and a step of relaxing the protein fibers in the heated state to cause them to irreversibly shrink (relaxation and shrinkage step).

[0247] In the heating step, the heating temperature is preferably equal to or higher than the softening temperature of the protein used in the protein fiber. In this specification, the softening temperature of the protein is the temperature at which the protein fiber starts to shrink due to stress relaxation. In the heat relaxation shrinkage at or higher than the softening temperature of the protein, the fiber shrinks to an extent that cannot be obtained by simply removing water from the fiber, and as a result, the obtained protein fiber is sufficiently suppressed from shrinking due to contact with water, i.e., dimensional change. The heating temperature is preferably 80°C or higher, more preferably 180°C to 280°C, even more preferably 200°C to 240°C, and even more preferably 220°C to 240°C.

[0248] From the viewpoint of the elongation of the fiber after the heat treatment, the heating time in the heating step is preferably 60 seconds or less, more preferably 30 seconds or less, and even more preferably 5 seconds or less. It is considered that the length of this heating time does not have a significant effect on the stress.

[0249] In the relaxation contraction step, the relaxation ratio is preferably more than 1, more preferably 1.4 or more, even more preferably 1.7 or more, and particularly preferably 2 or more. The relaxation ratio is understood as, for example, the ratio of the delivery speed to the winding speed of the protein fiber.

[0250] (Protein Fiber and Protein) In the artificial fur according to the second embodiment, the protein fibers are shrink-proofed by carrying out the shrink-proofing treatment described above, so that dimensional changes due to contact with water are suppressed. Therefore, the protein fibers (and proteins) used in the artificial fur may be those that would otherwise undergo (significant) dimensional changes due to contact with water.

[0251] For example, the protein fiber may have a wet shrinkage of 2% or more. The wet shrinkage may be 4% or more, 6% or more, 8% or more, 10% or more, 15% or more, 20% or more, 25% or more, or 30% or more. The upper limit of the wet shrinkage is usually 80% or less. The wet shrinkage is defined by the following formula I. Wet shrinkage rate = {1 - (length of protein fiber wetted by contact with water / length of protein fiber after spinning and before contact with water)} x 100 (%) ... (Equation I)

[0252] For example, the protein fiber may have a dry shrinkage rate of more than 7%. The dry shrinkage rate may be 15% or more, 25% or more, 32% or more, 40% or more, 48% or more, 56% or more, 64% or more, or 72% or more. The upper limit of the dry shrinkage rate is usually 80% or less. The dry shrinkage rate is defined by the following formula II. Dry shrinkage rate = {1 - (length of protein fiber in a dry state / length of protein fiber after spinning and before contact with water)} x 100 (%) ... (Formula II)

[0253] There is no particular limitation on the protein that is the raw material of the protein fiber, and any protein can be used. Examples of proteins include natural proteins and recombinant proteins (artificial proteins). Examples of recombinant proteins include any protein that can be produced on an industrial scale, such as proteins that can be used for industrial purposes, proteins that can be used for medical purposes, structural proteins, etc. Specific examples of proteins that can be used for industrial or medical purposes include enzymes, regulatory proteins, receptors, peptide hormones, cytokines, membrane or transport proteins, antigens used in vaccinations, vaccines, antigen-binding proteins, immunostimulating proteins, allergens, full-length antibodies, or antibody fragments or derivatives. Specific examples of structural proteins include spider silk, silkworm silk, keratin, collagen, elastin, and resilin, as well as proteins derived therefrom. The protein used is preferably modified fibroin, more preferably modified spider silk fibroin, because it has excellent heat retention, moisture absorption and heat generation properties, and / or flame retardancy. When the protein is modified fibroin (preferably modified spider silk fibroin), the artificial fur according to this embodiment has heat retention and moisture absorption and heat generation properties. And / or flame retardant properties can be further imparted, making the material more valuable as artificial fur.

[0254] The modified fibroin used in the artificial fur according to this embodiment (second embodiment) may be the same as the modified fibroin used in the artificial fur according to the first embodiment described above.

[0255] (artificial fur) The artificial fur according to this embodiment may contain fibers other than protein fibers, provided that the effect of the present invention is not impaired. Examples of the other fibers include the same fibers as those that can be contained in the artificial fur according to the first embodiment described above.

[0256] The artificial fur according to this embodiment may further contain other components in addition to the fibers. Examples of the other components include the same components that can be contained as other components in the artificial fur according to the first embodiment described above.

[0257] The artificial fur according to this embodiment may have the above-mentioned maximum moisture absorption heat value, limit oxygen index (LOI) value, and heat retention index, similar to the artificial fur according to the first embodiment.

[0258] (Manufacturing method of artificial fur) The artificial fur according to this embodiment can be obtained by a method using the above-mentioned fibers (fibers containing protein fibers) and comprising the steps of obtaining a pile fabric having pile protruding from one or both sides of the fabric (pile fabric manufacturing step), cutting (shearing) the pile loops to form cut pile (cut hair) (shearing step), shrink-proofing (shrink-proofing step), and, if necessary, combing the cut pile (cut hair) (combing step) and / or washing the woven fabric on which the cut pile (cut hair) has been formed (washing step). The form of the fibers used in the pile fabric manufacturing step is not particularly limited as long as they contain protein fibers. That is, for example, they may be twisted yarns made by twisting bundles of filaments together or spun yarns made of staples.

[0259] Specifically, for example, a manufacturing method according to one embodiment includes a step of shrink-proofing protein fibers (shrink-proofing step). Here, the protein fibers may be shrink-proofed before being bundled, twisted, or spun (in the form of filaments or staples), or may be shrink-proofed after being bundled, twisted, or spun. The method according to the present embodiment also includes a step of using the shrink-proof protein fibers to obtain pile fabric having pile woven and protruding on one or both sides of the fabric (pile fabric manufacturing step), and a step of cutting the pile loops to form cut pile (shearing step). If necessary, a combing step may be performed. And / or a washing step may be further included.

[0260] A manufacturing method according to another embodiment includes a step of obtaining a pile fabric having pile protrusions on one or both sides of the fabric by, for example, pile weaving or pile knitting using fibers containing protein fibers (pile fabric manufacturing step), a step of cutting the pile loops to form cut pile (shrink-proof step), and a step of shrink-proofing the pile fabric (shrink-proof step). If necessary, the method may further include a combing step and / or a washing step. The shrink-proof step may be performed before or after the shearing step.

[0261] The shrink-proofing step can be carried out in the manner described in the shrink-proofing treatment.

[0262] The pile fabric manufacturing process and the shearing process may be the same as the pile fabric manufacturing process and the shearing process employed in the manufacture of the artificial leather according to the first embodiment described above. It is possible.

[0263] The spun yarn may be any yarn that has been spun, and may also be a twisted yarn that has been further twisted. The spun yarn can be obtained, for example, by a method including a step of spinning a fiber raw material in a conventional manner to obtain a fiber (spinning step), a step of crimping the obtained fiber as necessary (crimping step), a step of cutting the fiber to obtain staples (short fibers) (cutting step), a step of opening and / or defibrating the staples as necessary (opening step), and a step of spinning the staples (spinning step).

[0264] The spinning step can be carried out according to a conventional method. The spinning method may be any of wet spinning, dry spinning, dry-wet spinning, and melt spinning.

[0265] The crimping step may be carried out as necessary, and may be carried out by a mechanical crimping method such as a pressing method.

[0266] The cutting step, the opening step, and the spinning step may be the same as the cutting step, the opening step, and the spinning step employed in the manufacture of the artificial leather according to the first embodiment. The length of the staple obtained by the cutting step is not particularly limited, but may be, for example, 20 mm or more, and may be 20 to 140 mm, 70 to 140 mm, or 20 to 70 mm.

[0267] <Third embodiment> The artificial fur according to the third embodiment in accordance with the third invention contains fibers and is further endowed with functionality.

[0268] Fibers that can be used in the artificial leather according to this embodiment (third embodiment) include synthetic fibers such as nylon, polyamide, polyester, polyacrylonitrile, polyolefin, polyvinyl alcohol, polyethylene terephthalate, polytetrafluoroethylene, and acrylic resin; regenerated fibers such as cupra, rayon, and lyocell; natural fibers such as cotton, hemp cotton, silk, wool, and cashmere; artificial fibers such as protein fibers; and composite fibers thereof.

[0269] The fiber preferably contains modified fibroin, more preferably modified spider silk fibroin. By containing modified fibroin (preferably modified spider silk fibroin), the artificial fur can be endowed with heat retention, moisture absorption and heat generation, and / or flame retardancy. The modified fibroin may be contained in the artificial fur as modified fibroin fiber (protein fiber), or a composite fiber of modified fibroin fiber and other fiber. The modified fibroin preferably contained in the fiber that provides the artificial fur according to this embodiment (third embodiment) may be the same as the modified fibroin used in the artificial fur according to the first and second embodiments described above.

[0270] The artificial fur according to this embodiment may be one which is imparted with functionality by further containing a functionality-imparting substance (for example, a specific protein crosslinker or modified hydroxyl group-containing polymer in the second and third methods described below) in addition to ordinary fibers, or one which is imparted with functionality by containing fibers to which functionality has been imparted (for example, fibers containing modified fibroin in the first method described below, and fibers containing a specific protein crosslinker or modified hydroxyl group-containing polymer in the second and third methods described below). This is also fine.

[0271] Methods for imparting functionality to artificial fur include, for example, a method of incorporating modified fibroin into the artificial fur (first method), a method of incorporating a specific protein crosslinker into the artificial fur (second method), and a method of incorporating a modified hydroxyl group-containing polymer in which a functional functional group is bonded to a hydroxyl group-containing polymer into the artificial fur (third method).

[0272] (First Method) In the first method, for example, a fiber (protein fiber or composite fiber) containing modified fibroin is used as a raw material to obtain a functionalized artificial fur. The fiber containing modified fibroin can be obtained by spinning a raw material containing modified fibroin according to a conventional method. By including modified fibroin in the fiber, the fiber can be endowed with heat retention, moisture absorption heat generation, and / or flame retardancy, and thus the artificial fur according to this embodiment can be endowed with heat retention, moisture absorption heat generation, and / or flame retardancy. As the modified fibroin, modified spider silk fibroin is preferable because it is superior in these functionalities. The modified fibroin is as described above.

[0273] (Second Method) The specified protein crosslinker in the second method has a polypeptide backbone, a plurality of first residues which are residues of a first reactant having two or more first reactive groups capable of reacting with a protein to form a bond, and a plurality of second residues which are residues of a second reactant having one second reactive group capable of reacting with the first reactive group to form a bond, wherein at least one of the first residues crosslinks the polypeptide backbone, and at least one of the first residues is bonded to the polypeptide backbone at one end and to the second residue at the other end.

[0274] In the second method, for example, a fiber containing a specific protein crosslinker is used as a raw material to obtain an artificial fur to which functionality has been imparted. The fiber containing the specific protein crosslinker can be obtained, for example, by spinning a raw material containing a specific protein crosslinker in a conventional manner. The fiber containing the specific protein crosslinker can also be obtained by spinning a raw material containing a protein in a conventional manner to obtain a protein fibril or composite fibril (precursor), and then reacting the fibril (precursor) with a first reactant and a second reactant to crosslink the protein in the fibril and generate a specific protein crosslinker. In the second method, for example, a mixture of ordinary fiber and a specific protein crosslinker can also be used as a raw material to obtain an artificial fur to which functionality has been imparted.

[0275] More specifically, the second method includes a first step of reacting a protein-containing molded body precursor with a first reactant having two or more first reactive groups capable of reacting with the protein to form a bond to obtain an intermediate, and a second step of reacting the intermediate with a second reactant having one second reactive group capable of reacting with the first reactive group to form a bond to obtain a molded body. The "molded body" in this method includes, for example, a predetermined protein crosslinked body itself (the molded body precursor is the protein itself), or a protein fiber or a composite fiber containing a protein (the molded body precursor is a protein fibril, or a composite fibril containing a protein).

[0276] The first step is a step of reacting a molded body precursor containing a protein with a first reactant. The first reactant is a polyfunctional reactant having two or more first reactive groups capable of reacting with the protein to form a bond, and in the first step, the protein may be crosslinked by the first reactant.

[0277] The protein has at least one reactive functional group selected from the group consisting of an amide group, a hydroxyl group, a phenolic hydroxyl group, an amino group, a carboxyl group, a thiol group, a selenol group, an imidazolyl group, an indolyl group, and a guanidino group. The first reactive group of the first reactant may be a group capable of reacting with the reactive functional group to form a bond.

[0278] The first reactive group is preferably an electrophilic group. When the first reactive group is an electrophilic group, it can easily form a bond with the reactive functional group of a protein by an addition reaction.

[0279] The first reactive group, which is an electrophilic group, is preferably, for example, a group represented by the following formula (A-1), (A-2), (A-3), (A-4), (A-5) or (A-6), in which the wavy lines represent bonds of each group.

[0280] [ka]

[0281] In formula (A-1), X 1 represents an oxygen atom (O) or a sulfur atom (S). 1 As the atom, an oxygen atom is more preferable.

[0282] In formula (A-3), X 2 indicates a leaving group. The leaving group is not particularly limited, and may be any group capable of undergoing a nucleophilic substitution reaction with a reactive functional group of a protein. Examples of leaving groups include halogen atoms (fluorine atom (F), chlorine atom (Cl), bromine atom (Br), iodine atom (I)), sulfonate ester groups (-OSOR), and the like. 1 ), carboxylate group (-OCOR 2 ), quaternary ammonium group (-NR 3 3) etc. 1 R may be, for example, a fluorine atom, an alkyl group, an aryl group, a halogenated alkyl group, or a halogenated aryl group. 2 is, for example, an alkyl group, an aryl group, a halogenated alkyl group, or a halogenated aryl group. R 3 R may be, for example, an alkyl group, an aryl group, a halogenated alkyl group, or a halogenated aryl group. 1 , R 2 and R 3 may have a substituent. Examples of the substituent include an alkyl group, an alkenyl group, an aryl group, and a halogen atom.

[0283] X 2 R is more preferably a chlorine atom, a bromine atom, an iodine atom, an ester group, or a sulfonate group, and further preferably a bromine atom, an iodine atom, or a sulfonate group. 1 More preferred examples of R include a fluorine atom, an alkyl group (particularly, a methyl group, an ethyl group, a benzyl group, and an allyl group), a perfluoroalkyl group (particularly, a trifluoromethyl group and a pentafluoroethyl group), and an aryl group (particularly, a phenyl group, a tolyl group, a naphthyl group, and a fluorophenyl group). 2Examples of the alkyl group include alkyl groups (especially methyl groups, ethyl groups, benzyl groups, and allyl groups), perfluoroalkyl groups (especially trifluoromethyl groups, pentafluoromethyl groups, R is preferably an aryl group (particularly, a phenyl group, a tolyl group, a naphthyl group, or a fluorophenyl group), or an aryl group (particularly, a phenyl group, a tolyl group, a naphthyl group, or a fluorophenyl group). 3 As the alkyl group, an alkyl group (particularly, a methyl group, an ethyl group, a benzyl group, and an allyl group), an aryl group (particularly, a phenyl group, a tolyl group, a naphthyl group, and a fluorophenyl group) and the like are more preferable.

[0284] In formula (A-4), X 3 is an oxygen atom (O), a sulfur atom (S), -NR 4 -, or -C(R 5 )2- represents a group represented by R 4 R may be, for example, a hydrogen atom, an alkyl group, an aryl group, a halogenated alkyl group or an aryl group, an arylsulfonyl group, an alkylsulfonyl group, an acyl group, or a carbamate group. 5 represents an electron-withdrawing group. Examples of the electron-withdrawing group include a carbonyl group, a cyano group, an aryl group, an alkenyl group, and an alkynyl group. Two R 5 may be the same or different. 4 and R 5 may have a substituent. Examples of the substituent include an alkyl group, an alkenyl group, an aryl group, and a halogen atom.

[0285] X 3 As R, an oxygen atom is more preferable. 4 As the group, an arylsulfonyl group, an alkylsulfonyl group, an acyl group, a carbamate group, and the like are more preferable.

[0286] In formula (A-5), X 4 represents an oxygen atom (O) or a sulfur atom (S), and Y 1 is a halogen atom, a hydroxyl group, -R 6 a group represented by -OR 6 or -OCOR 6 R represents a group represented by the formula:6 R may be, for example, an alkyl group, an aryl group, a halogenated alkyl group, or a halogenated aryl group. 6 may have a substituent. Examples of the substituent include an alkyl group, an alkenyl group, an aryl group, and a halogen atom.

[0287] X 4 As Y, an oxygen atom is more preferable. 1 Examples of the halogen atom include -OR 6 or -OCOR 6 More preferred are groups represented by the following formula: R 6 As the alkyl group, an alkyl group, an aryl group, etc. are more preferable.

[0288] In formula (A-6), X 5 represents an oxygen atom (O) or a sulfur atom (S), and Y 2 is an oxygen atom (O), a sulfur atom (S) or NR 7 R represents a group represented by the formula: 7 R may be, for example, an alkylsulfonyl group, an arylsulfonyl group, an acyl group, a carbamate group, an alkyl group, an aryl group, a halogenated alkyl group, or a halogenated aryl group. 7 may have a substituent. Examples of the substituent include an alkyl group, an alkenyl group, an aryl group, and a halogen atom.

[0289] X 5 As Y, an oxygen atom is more preferable. 2 As R, an oxygen atom is more preferable. 7 As the group, an alkylsulfonyl group, an arylsulfonyl group, an acyl group, a carbamate group, and the like are more preferable.

[0290] The first reactant may be a compound having two or more first reactive groups. The number of first reactive groups in the first reactant is not particularly limited and may be, for example, 2 to 10,000, and preferably 2 to 1,000.

[0291] The first step may be carried out, for example, by contacting a first reaction liquid containing a first reactant with a molded body precursor and heating the mixture.

[0292] The first reaction liquid may be solvent-free or may further contain a solvent. The solvent of the first reaction liquid is not particularly limited, and may be, for example, any solvent that can dissolve the first reactant and does not inhibit the reaction between the reactive functional group of the protein and the first reactive group. When the first reactive group is an electrophilic group, for example, N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, benzene, toluene, xylene, mesitylene, tetrahydrofuran, dimethylsulfoxide, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, etc. can be suitably used as the solvent of the first reaction liquid. can.

[0293] The reaction conditions in the first step are not particularly limited as long as they allow the reactive functional group of the protein to react with the first reactive group.

[0294] In the first step, it is preferable that at least a part of the first reactant crosslinks the protein and at least a part of the first reactive groups remain in the intermediate, i.e., in the first step, it is preferable that an intermediate containing the protein crosslinked by the first reactant and having the first reactive groups is obtained.

[0295] For example, when the first reactive agent is a compound having two first reactive groups, a portion of the first reactive agent may crosslink the protein (i.e., both first reactive groups react with the protein), and another portion of the first reactive groups may react with the protein at only one of the first reactive groups, and in this case, the other first reactive group may remain unreacted in the intermediate.

[0296] Furthermore, for example, when the first reactive agent is a compound having three or more first reactive groups, a portion of the first reactive agent may crosslink the protein at all of the first reactive groups (i.e., all of the first reactive groups have reacted with the protein), and another portion of the first reactive agent may have some of the first reactive groups reacted with the protein and some of the first reactive groups remain unreacted in the intermediate.

[0297] The reaction of the first step can be said to be a reaction in which a crosslinked structure or a side chain having a first reactive group is formed by using the first reactant starting from the reactive functional group of the protein. The amount of the crosslinked structure and the side chain can be adjusted by the amount of the first reactant used in the reaction. By using a smaller amount of the first reactant, there is a tendency that fewer side chains and more crosslinked structures are formed, and by using a larger amount of the first reactant, there is a tendency that fewer crosslinked structures and more side chains are formed.

[0298] The adjustment of the amount of crosslinked structures and side chains can also be achieved, for example, by carrying out a pre-step in which a part of the first reactive group of the first reactant is reacted with the second reactive group of the second reactant prior to carrying out the first step. By appropriately adjusting the amount of the second reactant used in such a pre-step relative to the first reactant, the number of first reactive groups remaining without reacting with the second reactive group in the pre-step can be controlled. This makes it possible to easily adjust the amount of binding of the first reactive group to the protein in the first step, and as a result, it becomes possible to easily control the amount of crosslinked structures and side chains of the protein.

[0299] That is, the second method may further include a pre-step, prior to the first step, of reacting a portion of the first reactant with a portion of the second reactant to react a portion of the first reactive group carried by the first reactant with a portion of the second reactive group carried by the second reactant.

[0300] By forming a large number of crosslinked structures, the water resistance (e.g., the property of being able to suppress the amount of shrinkage due to contact with moisture, the property of being able to suppress the amount of shrinkage when drying after contact with moisture, etc.), mechanical strength, heat resistance, etc. of the molded article tend to be improved, and by forming a large number of side chains, the functionality imparted to the molded article (e.g., the texture described below) tends to be improved. In the second method, the proportions of crosslinked structures and side chains may be appropriately adjusted depending on the desired properties.

[0301] In the first step, an intermediate containing a reaction product of a protein and a first reactant is obtained. In the reaction product, the protein is crosslinked by the first reactant, and unreacted first reactive groups may remain. That is, the reaction product may contain a polypeptide backbone derived from the protein, a crosslinking portion that crosslinks the polypeptide backbone, and a side chain portion that is bound to the polypeptide backbone and has a first reactive group at its end.

[0302] The second step is a step of reacting the intermediate obtained in the first step with a second reactant. The second reactant has one second reactive group capable of reacting with the first reactive group to form a bond. The second step can also be said to be a step of reacting the first reactive group remaining in the intermediate with the second reactant.

[0303] The second reactive group of the second reactant is not particularly limited and may be appropriately changed depending on the type of the first reactive group. For example, when the first reactive group is an electrophilic group, the second reactive group is preferably a nucleophilic group.

[0304] Examples of the second reactive group that is a nucleophilic group include a hydroxyl group, a thiol group, an amino group, and a group represented by the following formula (B-1).

[0305] [ka]

[0306] In formula (B-1), X 6 represents an oxygen atom (O) or a sulfur atom (S).

[0307] An example of the group represented by formula (B-1) is a group represented by the following formula (B-1-1).

[0308] [ka]

[0309] In formula (B-1-1), Y 3 represents a monovalent group. Y 3 Y may be, for example, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, an alkylsulfide group, an arylsulfide group, a mono-substituted amino group, a di-substituted amino group, or the like, and is preferably an alkyl group, an aryl group, an alkoxy group, or a mono-substituted amino group. 3 may have a substituent. Examples of the substituent include an alkyl group, an alkenyl group, an aryl group, and a halogen atom.

[0310] The second reactant may be a compound having one second reactive group, and may further have a functional group that is inactive in the reaction of the second step (the reaction between the first reactive group and the second reactive group). With such a second reactant, the functional group can be easily introduced into the molded body starting from the unreacted first reactive group in the intermediate.

[0311] The functional group is not particularly limited, and may be a group that directly imparts functionality to the molded article, or a group that imparts reactivity with an additional reactant to the molded article.

[0312] Examples of functional groups include hydrocarbon groups such as alkyl groups, alkenyl groups, and alkynyl groups; groups having a ring structure such as aryl groups and heterocyclic groups; reactive groups protected by a protecting group (hydroxyl group, amino group, thiol group, and the like); groups having a structure such as a carbonyl group (-C(=O)-), an ether bond (-O-), an amide bond (>NC(=O)-), a urethane bond (>NC(=O)O-), a urea bond (>N(C=O)N<) or a carbonate bond (-OC(=O)O-); an alkoxysilyl group, a sulfonyl group (-S(=O)-), a carboxyl group (-C(=O)OH), a sulfonic acid group (-S(=O)OH), and a quaternary ammonium group.

[0313] For example, when the functional group is an alkyl group, the texture of the molded article is improved. Therefore, for example, when the molded article is fibrous, a material with excellent texture and good feel can be obtained by using a second reactant having an alkyl group as the functional group.

[0314] In conventional protein materials, when water resistance or strength is improved by crosslinking, the feel of the material deteriorates, making it difficult to use for applications in which the material comes into contact with human skin. However, according to the second method, it is possible to obtain a material that is suitable for use in applications in which the material comes into contact with human skin, by providing excellent texture and feel through the functional groups while maintaining the water resistance and mechanical strength provided by the crosslinking.

[0315] The second step may be carried out, for example, by contacting the intermediate with a second reaction liquid containing a second reactant and heating the mixture.

[0316] The second reaction liquid may be solvent-free or may further contain a solvent. The solvent of the second reaction liquid is not particularly limited, and may be, for example, a solvent that can dissolve the second reactant and does not inhibit the reaction between the first reactive group and the second reactive group. When the first reactive group is an electrophilic group and the second reactive group is a nucleophilic group, for example, N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, benzene, toluene, xylene, mesitylene, tetrahydrofuran, dimethylsulfoxide, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, etc. can be suitably used as the solvent of the second reaction liquid.

[0317] In the second step, the amount of the second reactant used is not particularly limited. The amount of the second reactant used may be, for example, an amount that exceeds the amount of the first reactive group in the intermediate.

[0318] In the second step, a part or all of the first reactive groups in the intermediate are consumed by reacting with the second reactive groups. It is desirable that the first reactive groups do not remain in the molded body as much as possible. For this reason, in the second method, it is preferable that all of the first reactive groups are consumed by reacting with the second reactive groups or other side reactions.

[0319] In the second step, a molded body containing the crosslinked protein is obtained.

[0320] In the description of the second method, the first residue refers to the structure remaining after removing the first reactive group from the first reactant, and the second residue refers to the structure remaining after removing the second reactive group from the second reactant.

[0321] The polypeptide backbone and the first residue are linked by a bond formed by reaction of a reactive functional group of the protein with the first reactive group (e.g., a urea bond when the reactive functional group is an amino group and the first reactive group is an isocyanate group), and the first residue and the second residue are linked by a bond formed by reaction of the first reactive group with a second reactive group (e.g., a urethane bond when the first reactive group is an isocyanate group and the second reactive group is a hydroxyl group).

[0322] In the second method, the protein is crosslinked by the first reactant, and a molded article having excellent water resistance, mechanical strength, heat resistance, etc. In addition, in the second method, a functional group can be imparted by the second reactant starting from the first reactive group remaining in the intermediate, and thus molded articles having various functionalities can be easily obtained.

[0323] (Third Method) The modified hydroxyl group-containing polymer in the third method is a polymer in which a functional group is bonded to a hydroxyl group-containing polymer. The modified hydroxyl group-containing polymer can be obtained, for example, by reacting a hydroxyl group-containing polymer with a reactant having a functional group.

[0324] The hydroxyl group-containing polymer can be used without any particular limitation as long as it is a polymer compound having a hydroxyl group.Specific examples of the hydroxyl group-containing polymer include starch, glycogen, cellulose, chitin, agarose, hyaluronic acid, chondroitin sulfate, polysaccharides such as pectin and carrageenan, polyvinyl alcohol (PVA), and synthetic polymers such as phenolic resin.

[0325] As the hydroxyl group-containing polymer, polysaccharides are preferred from the viewpoint of biodegradability, and starch is preferred from the viewpoint of high solubility in addition to biodegradability.

[0326] The functional functional group is a functional group having properties (e.g., hydrophobicity, hydrophilicity) corresponding to the functionality (e.g., water resistance, hydrophilicity, lipophilicity, oil resistance) desired to be imparted, and can be appropriately selected depending on the functionality desired to be imparted.

[0327] For example, when it is desired to improve water resistance, hydrophobic functional groups such as alkyl groups, e.g., methyl groups, ethyl groups, n-propyl groups, isopropyl groups, etc., aromatic groups, e.g., phenyl groups, naphthyl groups, etc., and acyl groups, e.g., acetyl groups, propanoyl groups, benzoyl groups, etc., can be used as the functional groups.

[0328] The reactant having a functional group is a compound having a functional group and further having a binding functional group capable of binding to a hydroxyl group-containing polymer. The binding functional group may be any functional group capable of binding to a hydroxyl group-containing polymer through a hydrogen bond or a covalent bond, but is preferably a functional group capable of binding to a hydroxyl group-containing polymer through a covalent bond, and more preferably a functional group capable of binding to a hydroxyl group in a hydroxyl group-containing polymer through a covalent bond.

[0329] Examples of the reactant having a functional group include an isocyanate having a functional group (RN=C=O: R is a functional group), an acid anhydride (RC(=O)-OC(=O)-R: R is a functional group), an epoxide, an aziridine, and an alkyl halide. As the reactant having a functional group, an isocyanate having a functional group and an acetic anhydride having a functional group are preferred because they can be covalently bonded to the hydroxyl group in the hydroxyl group-containing polymer, and an isocyanate having a functional group is more preferred because any functional group can be introduced.

[0330] In the third method, for example, a fiber containing a modified hydroxyl group-containing polymer is used as a raw material to obtain a functionalized artificial fur. The fiber containing a modified hydroxyl group-containing polymer can be obtained, for example, by spinning a raw material containing a modified hydroxyl group-containing polymer according to a conventional method. In the third method, for example, a mixture of a normal fiber and a modified hydroxyl group-containing polymer is used as a raw material to obtain a functionalized artificial fur.

[0331] The content of the modified hydroxyl group-containing polymer contained in the raw material is not particularly limited and may be appropriately set depending on the functionality to be imparted, etc. The content of the modified hydroxyl group-containing polymer may be, for example, 0.001 to 70 mass%, 0.01 to 65 mass%, or 0.1 to 60 mass% based on the total mass of the artificial fur.

[0332] The modified hydroxyl group-containing polymer is preferably hydrogen bonded to the fiber. This further improves the functionality. The hydrogen bond can be formed, for example, between a functional group in the modified hydroxyl group-containing polymer (e.g., a hydroxyl group, a functional group in a functional functional group or a binding functional group, etc.) and a functional group in the fiber (e.g., an amino group, a carboxyl group, etc. in the case of a protein fiber).

[0333] In the third method, the artificial fur may further contain a hydroxyl group-containing polymer. The hydroxyl group-containing polymer is preferably the same type of polymer as the hydroxyl group-containing polymer that is the raw material of the modified hydroxyl group-containing polymer. When the hydroxyl group-containing polymer is contained, the content of the hydroxyl group-containing polymer may be 50% by mass or more, 60% by mass or more, 70% by mass or more, or 80% by mass or more relative to 100% by mass of the total amount of the modified hydroxyl group-containing polymer and the hydroxyl group-containing polymer. The upper limit may be 90% by mass or less.

[0334] The artificial fur obtained by the above-mentioned second or third method may or may not contain modified fibroin.

[0335] The artificial fur according to this embodiment may further contain other components in addition to the fibers, such as the above-mentioned specific protein crosslinker and modified hydroxyl group-containing polymer, as well as colorants, smoothing agents, antioxidants, UV absorbers, dyes, fillers, crosslinking agents, matting agents, leveling agents, etc.

[0336] The artificial fur according to this embodiment, when made using fibers containing modified fibroin, may have the above-mentioned maximum moisture absorption heat value, limiting oxygen index (LOI) value, and heat retention index, similar to those of the artificial fur according to the first embodiment.

[0337] (Manufacturing method of artificial fur) The artificial fur of this embodiment can be manufactured, for example, using the above-mentioned fibers (fibers including artificial protein fibers) in a manner similar to that of the artificial fur of the first embodiment described above.

[0338] <Fourth Example> The artificial fur according to the fourth embodiment in accordance with the fourth invention comprises fibers and a water-resistance imparting substance.

[0339] Fibers that can be used in the artificial leather according to this embodiment (fourth embodiment) include synthetic fibers such as nylon, polyamide, polyester, polyacrylonitrile, polyolefin, polyvinyl alcohol, polyethylene terephthalate, polytetrafluoroethylene, and acrylic resin; regenerated fibers such as cupra, rayon, and lyocell; natural fibers such as cotton, hemp cotton, silk, wool, and cashmere; artificial fibers such as protein fibers; and composite fibers thereof.

[0340] The fiber preferably contains modified fibroin, more preferably modified spider silk fibroin. By containing modified fibroin (preferably modified spider silk fibroin), the artificial fur can be endowed with heat retention, moisture absorption and heat generation, and / or flame retardancy. The modified fibroin may be contained in the artificial fur as modified fibroin fiber (protein fiber) or a composite fiber of modified fibroin fiber and other fiber. The modified fibroin preferably contained in the fiber that provides the artificial fur according to this embodiment (fourth embodiment) may be the same as the modified fibroin used in the artificial fur according to the first to third embodiments described above.

[0341] Protein fibers can be obtained, for example, by dissolving a protein in a solvent capable of dissolving the protein to prepare a dope solution, and spinning the solution by a known spinning method such as wet spinning, dry spinning, dry-wet spinning, or melt spinning. Examples of solvents capable of dissolving proteins include dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), formic acid, and hexafluoroisopropanol (HFIP). An inorganic salt may be added to the solvent as a dissolution promoter.

[0342] The protein fiber containing the modified fibroin may contain other proteins other than the modified fibroin. There are no particular limitations on the other proteins, and any proteins can be used.

[0343] (Water resistance imparting substance) The water-resistance imparting substance is a substance that can improve the water resistance of the artificial fur. When the artificial fur contains the water-resistance imparting substance, for example, the water repellency of the artificial fur is improved, and the shrinkage of the artificial fur when it comes into contact with water is suppressed, and the waterproofness of the artificial fur is further improved. The artificial fur may contain one type of water-resistance imparting substance alone, or may contain two or more types.

[0344] Specific examples of the water-resistance imparting substance include hydrophobic polymers such as fluorine-based polymers and silicone-based polymers, and modified hydroxyl-containing polymers in which hydrophobic functional groups are bound to hydroxyl-containing polymers. When the artificial fur contains protein, further specific examples of the water-resistance imparting substance include protein binders such as polyfunctional reactants (first reactants) having two or more first reactive groups capable of reacting with protein to form bonds, and reactants having one or more first reactive groups capable of reacting with protein to form bonds and a functional group.

[0345] The fluorine-based polymer is not particularly limited as long as it is a polymer containing fluorine. The fluorine-based polymer may be, for example, a polymer obtained by polymerizing an olefin containing fluorine. Examples of the fluorine-based polymer include polytetrafluoroethylene, polytrifluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polyperfluoroalkylvinyl ether, polyperfluoropropylene, polytetrafluoroethylene-perfluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, and polyvinyl fluoride-ethylene copolymer. The fluorine-based polymer may be a copolymer (including a random copolymer, a block copolymer, or an alternating copolymer) obtained by polymerizing two or more kinds of monomers constituting the exemplified polymers.

[0346] The silicone polymer is not particularly limited as long as it is a polymer having a polysiloxane structure in the main chain. The silicone polymer may be, for example, a homopolymer or copolymer (including random copolymer, block copolymer, or alternating copolymer) obtained by polymerizing one or more monomers having a siloxane structural unit. The silicone polymer may be a copolymer (including random copolymer, block copolymer, or alternating copolymer) obtained by polymerizing one or more monomers having a siloxane structural unit and one or more monomers not having a siloxane structural unit.

[0347] The modified hydroxyl group-containing polymer is a polymer in which a hydrophobic functional group is bonded to a hydroxyl group-containing polymer. The modified hydroxyl group-containing polymer can be obtained, for example, by reacting a hydroxyl group-containing polymer with a reactant having a hydrophobic functional group.

[0348] The hydroxyl group-containing polymer can be used without any particular limitation as long as it is a polymeric compound having a hydroxyl group.Specific examples of the hydroxyl group-containing polymer include starch, glycogen, cellulose, chitin, agarose, hyaluronic acid, chondroitin sulfate, pectin, carrageenan, and other polysaccharides, polyvinyl alcohol (PVA), phenolic resin, and other synthetic polymers.As the hydroxyl group-containing polymer, polysaccharides are preferred from the viewpoint of having biodegradability.In addition, as the hydroxyl group-containing polymer, starch is preferred from the viewpoint of having biodegradability and high solubility.

[0349] The reactant having a hydrophobic functional group is a compound having a hydrophobic functional group and further having a binding functional group capable of binding to a hydroxyl group-containing polymer. The binding functional group may be capable of binding to a hydroxyl group-containing polymer by a hydrogen bond or a covalent bond, but is preferably a functional group capable of binding to a hydroxyl group-containing polymer by a covalent bond, and more preferably a functional group capable of binding to a hydroxyl group in a hydroxyl group-containing polymer by a covalent bond. Examples of the hydrophobic functional group include alkyl groups such as methyl, ethyl, n-propyl, and isopropyl groups, aromatic groups such as phenyl and naphthyl groups, and acyl groups such as acetyl, propanoyl, and benzoyl groups. Examples of the reactant having a hydrophobic functional group include isocyanates (RN=C=O:R is a hydrophobic functional group), acid anhydrides (RC(=O)-OC(=O)-R:R is a hydrophobic functional group), epoxides, aziridines, and alkyl halides having a hydrophobic functional group.

[0350] The content of the above-mentioned hydrophobic polymer in the artificial fur of this embodiment may be 0.001 to 70 mass%, 0.01 to 65 mass%, 0.1 to 60 mass%, 1 to 50 mass%, 1 to 40 mass%, 1 to 30 mass%, 1 to 20 mass%, 1 to 10 mass%, or 1 to 5 mass%, based on the total amount of the artificial fur.

[0351] Examples of protein binders include polyfunctional reactants (first reactants) having two or more first reactive groups capable of reacting with a protein to form a bond, and reactants (functional reactants) having one or more first reactive groups capable of reacting with a protein to form a bond and a functional group.

[0352] The first reactant has a first reactive group capable of reacting with at least one reactive functional group selected from the group consisting of an amide group, a hydroxyl group, a phenolic hydroxyl group, an amino group, a carboxyl group, a thiol group, a selenol group, an imidazolyl group, an indolyl group, and a guanidino group contained in the protein to form a bond.

[0353] Examples of the first reactive group include groups represented by the following formulae (A-1), (A-2), (A-3), (A-4), (A-5) and (A-6). The wavy lines in each formula represent bonds of each group. [ka]

[0354] In formula (A-1), X 1 represents an oxygen atom (O) or a sulfur atom (S). 2 represents a leaving group. In formula (A-4), X 3 is an oxygen atom (O), a sulfur atom (S), -NR 4 -, or -C(R 5 )2- represents a group represented by R 4R may be, for example, a hydrogen atom, an alkyl group, an aryl group, a halogenated alkyl group or an aryl group, an arylsulfonyl group, an alkylsulfonyl group, an acyl group, or a carbamate group. 5 In formula (A-5), X represents an electron-withdrawing group. 4 represents an oxygen atom (O) or a sulfur atom (S), and Y 1 is a halogen atom, a hydroxyl group, -R 6 a group represented by -OR 6 or -OCOR 6 R represents a group represented by the formula: 6 is, for example, an alkyl group, an aryl In formula (A-6), X may be a halogenated alkyl group or a halogenated aryl group. 5 represents an oxygen atom (O) or a sulfur atom (S), and Y 2 is an oxygen atom (O), a sulfur atom (S) or NR 7 R represents a group represented by the formula: 7 may be, for example, an alkylsulfonyl group, an arylsulfonyl group, an acyl group, a carbamate group, an alkyl group, an aryl group, a halogenated alkyl group, or a halogenated aryl group.

[0355] The functional reactant can be obtained by reacting a first reactant with a reactant (second reactant) having a functional group and a second reactive group (one) capable of reacting with the first reactive group to form a bond.

[0356] Examples of the second reactive group include a hydroxyl group, a thiol group, an amino group, and a group represented by the following formula (B-1). [ka]

[0357] In formula (B-1), X 6 represents an oxygen atom (O) or a sulfur atom (S).

[0358] Examples of functional groups include hydrocarbon groups such as alkyl groups, alkenyl groups, and alkynyl groups; groups having a ring structure such as aryl groups and heterocyclic groups; reactive groups protected by a protecting group (hydroxyl group, amino group, thiol group, and the like); groups having a structure such as a carbonyl group (-C(=O)-), an ether bond (-O-), an amide bond (>NC(=O)-), a urethane bond (>NC(=O)O-), a urea bond (>N(C=O)N<) or a carbonate bond (-OC(=O)O-); an alkoxysilyl group, a sulfonyl group (-S(=O)-), a carboxyl group (-C(=O)OH), a sulfonic acid group (-S(=O)OH), and a quaternary ammonium group.

[0359] A specific example of the first reactant is hexane diisocyanate (HDI), and a specific example of the second reactant is butanol (BuOH).

[0360] The water-resistance imparting substance is preferably a fluorine-based polymer or a silicone-based polymer, from the viewpoint of improving the water repellency of the artificial fur and suppressing shrinkage upon contact with water.

[0361] Methods for incorporating a water-resistance imparting substance into artificial fur include, for example, a method of producing an artificial fur in accordance with a conventional method using fibers containing a water-resistance imparting substance (for example, fibers mixed with a water-resistance imparting substance, or fibers to which a water-resistance imparting substance is bound) (method according to a first embodiment), a method of mixing a water-resistance imparting substance with an artificial fur produced from fibers that do not contain a water-resistance imparting substance (method according to a second embodiment), and a method of binding a water-resistance imparting substance to an artificial fur produced from fibers that do not contain a water-resistance imparting substance (method according to a third embodiment). In the method according to the second embodiment, it is not necessary for the water-resistance imparting substance to be bound to the artificial fur.

[0362] The method according to the third embodiment includes a step of bonding a water-resistance imparting substance to the artificial fur (bonding step). The bonding step can be carried out, for example, by bringing the water-resistance imparting substance into contact with the artificial fur by means of coating or immersion, and then, if necessary, by heating or plasma irradiation, to bond the artificial fur to the water-resistance imparting substance. When the water-resistance imparting substance is a hydrophobic polymer, for example, a silicon-based polymer or a fluorine-based polymer, the bonding step can be, for example, a step of irradiating plasma while the artificial fur is in contact with the water-resistance imparting substance or a precursor (monomer) of the water-resistance imparting substance, to covalently bond the artificial fur to the water-resistance imparting substance. Even when a precursor (monomer) of the water-resistance imparting substance is used, the precursor (monomer) of the water-resistance imparting substance is polymerized by plasma irradiation to form a water-resistance imparting substance (a hydrophobic polymer such as a silicon-based polymer or a fluorine-based polymer), so that an artificial fur containing the water-resistance imparting substance can be obtained. The method according to the third embodiment can be carried out not only on the artificial fur, but also on pile fabric before the shearing step.

[0363] The plasma to be irradiated may be appropriately set depending on the type of artificial fur (fiber to be used) and the water resistance imparting substance (or its precursor). The flow rate of the discharge gas may be, for example, in the range of 0.1 L / min to 10 L / min. The plasma density of the generated plasma may be, for example, 1×10 13 cm -3 More than 1×10 15 cm -3 It may be within the following ranges: The discharge gas may be, for example, a rare gas such as helium, neon, argon, oxygen, nitrogen, etc. Air may also be used as the discharge gas.

[0364] Plasma irradiation can be performed using a known plasma irradiation device. For example, a plasma treatment device manufactured by Europlasma can be used as the plasma irradiation device. This can be done.

[0365] (artificial fur) The artificial fur according to the present embodiment may further contain other components in addition to the fibers and the water resistance imparting substance, such as colorants, smoothing agents, antioxidants, UV absorbers, dyes, fillers, crosslinking agents, matting agents, leveling agents, etc.

[0366] The artificial fur according to this embodiment, when made using fibers containing modified fibroin, may have the above-mentioned maximum moisture absorption heat value, limiting oxygen index (LOI) value, and heat retention index, similar to those of the artificial fur according to the first embodiment.

[0367] (Manufacturing method of artificial fur) The artificial fur of this embodiment can be manufactured, for example, using the above-mentioned fibers (fibers including artificial protein fibers) in a manner similar to that of the artificial fur of the first embodiment described above.

[0368] (Uses of artificial fur) The artificial fur of this embodiment (first to fourth embodiments) can be used in any application where known artificial fur (such as artificial fur made from synthetic fibers) is used (for example, clothing, accessories such as bags, carpets, stuffed toys, etc.). EXAMPLES

[0369] The present invention will be described in more detail below based on test examples, etc. However, the present invention is not limited to the following test examples.

[0370] [Test Example 1: Production of modified fibroin] Modified spider silk fibroin (PRT399) having the amino acid sequence shown in SEQ ID NO: 18, modified spider silk fibroin (PRT380) having the amino acid sequence shown in SEQ ID NO: 12, modified spider silk fibroin (PRT410) having the amino acid sequence shown in SEQ ID NO: 13, modified fibroin (PRT918) having the amino acid sequence shown in SEQ ID NO: 37, modified fibroin (PRT966) having the amino acid sequence shown in SEQ ID NO: 40, and modified fibroin (PRT799) having the amino acid sequence shown in SEQ ID NO: 15 were designed. A nucleic acid encoding the designed modified fibroin 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. This 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.

[0371] The resulting expression vector was used to transform E. coli BLR(DE3). The transformed E. coli was cultured in 2 mL of LB medium containing ampicillin for 15 hours. The culture was transferred to 100 mL of seed culture medium (Table 4) containing ampicillin at OD 200. 600 The culture temperature was kept at 30°C, and the OD 600 The flask culture was continued until the number of cells reached 5 (about 15 hours), and a seed culture solution was obtained.

[0372] [Table 4]

[0373] The seed culture solution was transferred to a jar fermenter containing 500 mL of production medium (Table 5) and the OD 600 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.

[0374] [Table 5]

[0375] Immediately after the glucose in the production medium was completely consumed, the feed solution (glucose 455g / 1L, yeast extract 120g / 1L) was added at a rate of 1mL / 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. Then, 1M isopropyl-β-thiogalactopyranoside (IPTG) was added to the culture solution to a final concentration of 1mM to induce the expression of the modified fibroin. After 20 hours had passed after the addition of IPTG, the culture solution was centrifuged and the cells were collected. SDS-PAGE was performed using the cells prepared from the culture solution before and after the addition of IPTG, and the expression of the modified fibroin of interest was confirmed by the appearance of a band of the desired modified fibroin size depending on the addition of IPTG.

[0376] The cells harvested 2 hours after addition of IPTG were diluted with 20 mM 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 disrupted cells were centrifuged to obtain a precipitate. The 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 cells were dialyzed against water using a dialysis tube (Cellulose tube 36 / 32, Sanko Junyaku Co., Ltd.). The white aggregated protein obtained after dialysis was collected by centrifugation, the water was removed using a freeze-dryer, and the freeze-dried powder was collected to obtain modified fibroins (PRT399, PRT380, PRT410, PRT918, PRT966, and PRT799).

[0377] PRT918 and PRT966 are hydrophobic modified fibroins with an average HI greater than 0. PRT410, PRT399, and PRT799 are hydrophilic modified fibroins with an average HI less than or equal to 0.

[0378] [Test Example 2: Production of modified fibroin fiber and evaluation of contractility (1)] Dimethyl sulfoxide (DMSO) in which LiCl was dissolved to a concentration of 4.0% by mass was prepared as a solvent, and freeze-dried powder of modified fibroin (PRT399, PRT380, PRT410, or PRT799) was added to the solvent to a concentration of 18% by mass or 24% by mass, and dissolved for 3 hours using a shaker. Insoluble matter and bubbles were then removed to obtain a modified fibroin solution.

[0379] The obtained modified fibroin solution was used as a dope solution (spinning stock solution) to produce spun and drawn modified spider silk fibroin fibers by dry-wet spinning using a spinning apparatus similar to the spinning apparatus 1000 shown in Figure 6. The spinning apparatus used was the same as the spinning apparatus 1000 shown in Figure 6, except that it further included a second undrawn yarn production apparatus (second bath) between the undrawn yarn production apparatus 102 (first bath) and the wet heat drawing apparatus 103 (third bath). The conditions for dry-wet spinning were as follows. Extrusion nozzle diameter: 0.2mm Coagulation bath temperature: 2~15℃ Total stretch ratio: 1 to 4 times Drying temperature: 60℃

[0380] (Shrinkage evaluation) The resulting modified fibroin fibers (Production Examples 1 to 19) were evaluated for shrinkage. That is, each modified fibroin fiber (fibers after spinning and before contact with water) was subjected to a shrinkage process in which the fiber was brought into a wet state by contact with water (contact step) and then dried (drying step), and the shrinkage rates of the wet modified fibroin fibers and those of the wet and then dried modified fibroin fibers were determined.

[0381] <Contact Step> From each of the wound modified fibroin fibers, a plurality of modified fibroin fibers for testing, each having a length of 30 cm, were cut out. The plurality of modified fibroin fibers were bundled together to obtain a modified fibroin fiber bundle having a fineness of 150 denier. A 0.8 g lead weight was attached to each modified fibroin fiber bundle, and in that state, each modified fibroin fiber bundle was immersed in water at the temperatures shown in Tables 6 to 9 for 10 minutes. The length of each modified fibroin fiber bundle was then measured in water. The measurement was performed while the 0.8 g lead weight was attached to the modified fibroin fiber bundle in order to eliminate crimping of the modified fibroin fiber bundle. Next, the shrinkage rate of the modified fibroin fiber in a wet state (shrinkage rate when wet) was calculated according to the following formula V. In formula V, L0 indicates the length (30 cm) of the modified fibroin fiber bundle before immersion in water, and Lw indicates the length of the modified fibroin fiber bundle immersed in water and wet. Wet shrinkage (%) = {1-(Lw / L0)} x 100 ... (Formula V)

[0382] <Drying step> After the contact step, the modified fibroin fiber bundle was removed from the water. The removed modified fibroin fiber bundle was left to dry at room temperature for 2 hours with a 0.8 g lead weight still attached. After drying, the length of each modified fibroin fiber bundle was measured. Next, the shrinkage rate (shrinkage rate when dried) of the modified fibroin fiber that had been moistened and then dried was calculated according to the following formula VI. In formula VI, L0 indicates the length (30 cm) of the modified fibroin fiber bundle before immersion in water, and Lwd indicates the length of the modified fibroin fiber bundle that had been moistened by immersion in water and then dried. Shrinkage rate during drying (%)={1-(Lwd / L0)}×100(%) …(Formula VI)

[0383] The results are shown in Tables 6 to 9. In Tables 6 to 9, "total draw ratio" indicates the total draw ratio in the spinning process.

[0384] [Table 6]

[0385] [Table 7]

[0386] [Table 8]

[0387] [Table 9]

[0388] The modified fibroin fiber had high shrinkage both when wet and when dry. On the other hand, the modified fibroin fiber that had been subjected to the above-mentioned shrinkage evaluation (shrinkage process) had a sufficiently reduced shrinkage when it was contacted with water again. It is considered that the above-mentioned shrinkage process relieves residual stress caused by stretching during spinning.

[0389] [Test Example 3: Production of modified fibroin fiber and evaluation of contractility (2)] The modified fibroin (PRT799) was added to formic acid to a concentration of 24% by mass, and dissolved at room temperature with stirring for 1 hour. After that, insoluble matter and bubbles were removed to obtain a modified fibroin solution.

[0390] The resulting modified fibroin solution was used as a dope solution (raw spinning solution) and subjected to dry-wet spinning using a spinning apparatus similar to the spinning apparatus 1000 shown in Figure 6 to obtain a modified fibroin fiber. The conditions for dry-wet spinning were as follows. Temperature of coagulation liquid (methanol): 5-10℃ Stretching ratio: 6x Drying temperature: 80℃

[0391] The modified fibroin fiber obtained was subjected to a thermal relaxation and shrinkage treatment. The modified fibroin fiber was passed over a dry hot plate while in contact with the dry hot plate heated to a prescribed temperature. The let-off speed was increased relative to the take-up speed to relax the modified fibroin fiber. The slack portion was then shrunk by heat, thereby performing a dry relaxation treatment. The relaxation ratio was determined by dividing the let-off speed by the take-up speed. In this test, the relaxation ratio was adjusted so that the slack portion of the modified fibroin fiber caused by excessive let-off was the limit shrinkage ratio (maximum shrinkage rate) at which relaxation can offset the slack portion. The relaxation ratio was adjusted by rotating at least one of the rollers on the let-off side and the roller on the take-up side. This was done by adjusting one of them.

[0392] The water shrinkage evaluation was carried out according to the following procedure. The fiber (test piece) after the heat relaxation shrinkage treatment was cut to 300 mm and immersed in 40°C water for 10 minutes without load. Immediately after that, the length of the test piece (wet length) was measured and it was dried at room temperature for 2 hours. Thereafter, the length of the test piece (fiber length after drying) was measured and the water shrinkage rate was measured. The water shrinkage rate is a numerical value calculated by the following formula (1). Water shrinkage rate = (1 - fiber length after drying / fiber length before immersion) × 100 (1)

[0393] (Test Example 3-1) The relationship between the heating temperature and the relaxation ratio was confirmed. In this Test Example 3-1, in all of Test Examples 3-1-1 to 3-1-7, the length before immersion in water was set to 300 mm, and the tests were performed by changing other conditions. Specifically, the tests were performed by changing the heating temperature, the relaxation ratio, and the residence time. Table 10 shows the temperature conditions, relaxation conditions, and the measurement results of the shrinkage ratio. As shown in Table 10, the higher the heating temperature and the higher the relaxation ratio, the lower the water shrinkage ratio. As shown in the results of Test Examples 3-1-3 to 3-1-5, a water shrinkage ratio of 4% or less was obtained by heating at 220°C or higher. Note that in Example 5, where the heating temperature was 280°C, coloring of the fibers was observed. As a result of this test, it was considered that the optimal heating temperature was 240°C.

[0394] [Table 10]

[0395] (Test Example 3-2) Next, the relationship between the relaxation ratio and the water shrinkage ratio was confirmed. In this Test Example 3-2, in all of Test Examples 3-2-1 to 3-2-6, the length before immersion in water was set to 300 mm, the heating temperature was set to 240°C, the residence time was set to 1 minute (60 seconds), and other conditions were changed to perform the tests. Specifically, the relaxation ratio (feeding speed) was changed to perform the tests. Table 11 shows the measurement results of the relaxation conditions and the shrinkage ratio. As shown in Table 11, the water shrinkage ratio decreased with an increase in the relaxation ratio. As shown in the results of Test Examples 3-2-3 to 3-2-5, a water shrinkage ratio of 16% or less was obtained by setting the relaxation ratio to 1.4 to 2.0 times.

[0396] [Table 11]

[0397] (Test Example 3-3) The relationship between various heating temperatures, heating times, and relaxation ratios and the water shrinkage ratio was confirmed. In this Test Example 3-3, Test Examples 3-3-1 to 3-3-10, the length before water immersion was set to 300 mm, and tests were performed while changing other conditions. Specifically, tests were performed while changing the heating temperature, heating time (residence time), and relaxation ratio (feed-off speed / winding speed). The temperature conditions and relaxation conditions, as well as the measurement results of the shrinkage ratio, are shown in Table 12. In Test Example 3-3-10, the test piece was only immersed in water and dried, and no relaxation or heating was performed. As shown in the results of Test Examples 3-3-4 to 3-3-9, the heating temperature was set to 200°C or more, and the relaxation ratio was not increased. By setting the heating temperature at 220°C or higher, a water shrinkage rate of less than 15% was obtained. By setting the heating temperature at 220°C or higher, a low water shrinkage rate of 4% or less was obtained. A residence time of 5 seconds was sufficient for shrinkage, and even if the residence time was extended, the shrinkage rate did not change significantly.

[0398] [Table 12]

[0399] [Test Example 4: Shrinkage prevention treatment and evaluation of knitted fabric using modified fibroin fiber] [Manufacturing, shrink-proofing and evaluation of knitted fabrics] (Test Example 4-1) A knitted fabric was produced by circular knitting using a seamless knitting machine using the modified fibroin fiber obtained in the same manner as in Test Example 2, except that the total draw ratio in the spinning process was 4.55 times. Here, the count of the modified fibroin fiber was 58.1 Nm, and the gauge number of the seamless knitting machine was 18.

[0400] A square mark with a side length of 1 cm was made in the wale direction and course direction of the knitted fabric obtained above.The knitted fabric was then immersed in water at 20°C for 10 minutes.The knitted fabric after immersion in water was dried to perform shrink prevention treatment.

[0401] <Measurement of dimensional change rate> The dimensional change rate (%) of the shrink-proofed knitted fabric was calculated in the wale direction and the course direction according to the following formula. In the formula, L0f is the length of one side written on the knitted surface before contact with water, and Lwf is the length of one side of a square written on the knitted surface after shrink-proofing. The results are shown in Table 13. Formula: Dimensional change rate = {(Lwf / L0f)-1} x 100 (%)

[0402] <Measurement of the increase rate of the number of loops> The number of loops per 1 cm in the wale direction and course direction of the knitted fabric obtained above and the knitted fabric that had been subjected to shrink-proofing were counted, and the increase rate of the number of loops was calculated according to the following formula. In the formula, N0 indicates the number of loops of the knitted fabric before contact with water, and Nw indicates the number of loops of the knitted fabric that had been subjected to shrink-proofing. The results are shown in Table 13. Formula: Loop number increase rate = {(Nw / N0)-1} x 100 (%)

[0403] <Measurement of knitting density increase rate> The knitted fabric obtained above and the knitted fabric that had been subjected to shrinkage treatment were 2 The number of loops per unit area was counted, and the increase rate of knitting density was calculated according to the following formula, where M0 represents the knitting density of the knitted fabric before contact with water, and Mw represents the knitting density of the knitted fabric after shrink-proofing. The results are shown in Table 13. Formula: Increase rate of knitting density = {(Mw / M0)-1} x 100 (%)

[0404] <Measurement of increase in burst strength> The knitted fabric obtained above and the knitted fabric that had been subjected to shrink-proofing treatment were subjected to bursting strength measurement in accordance with JIS L 1096 B method, and the increase rate of bursting strength was calculated according to the following formula. In the formula, R0 indicates the bursting strength of the knitted fabric before contact with water, and Rw indicates the bursting strength of the knitted fabric that had been subjected to shrink-proofing treatment. The results are shown in Table 13. Formula: Burst strength increase rate = {(Rw / R0)-1} x 100 (%)

[0405] (Test Example 4-2) Instead of the modified fibroin fiber, natural silk fibroin fiber (natural silk thread) was used, and a knitted fabric was knitted by weft knitting using a seamless knitting machine. Here, the natural silk fibroin fiber used was a bundle of two threads with a count of 29 Nm. The gauge number of the seamless knitting machine was 18. The obtained knitted fabric was subjected to a shrink-proofing treatment in the same manner as in Test Example 4-1. The dimensional change rate, the increase rate of the number of loops, and the increase rate of the knitting density were determined for the obtained knitted fabric and the knitted fabric that had been subjected to the shrink-proofing treatment. The results are shown in Table 13.

[0406] (Test Example 4-3) A knitted fabric was obtained in the same manner as in Test Example 4-1, except that polyethylene terephthalate (PET) fiber was used instead of the modified fibroin fiber. The obtained knitted fabric was subjected to a shrink-proofing treatment under the same conditions as in Test Example 4-1. The dimensional change rate, the increase rate of the number of loops, the increase rate of the knitting density, and the burst strength were determined for the obtained knitted fabric and the knitted fabric that had been subjected to the shrink-proofing treatment. The results are shown in Table 13.

[0407] (Test Example 4-4) A knitted fabric was obtained in the same manner as in Test Example 4-1, except that polyethylene terephthalate (PET) fiber was used instead of the modified fibroin fiber and the knitting method was changed from circular knitting to flat knitting. The obtained knitted fabric was subjected to shrink-proofing under the same conditions as in Test Example 4-1. The dimensional change rate, the increase rate of the number of loops, the increase rate of knitting density, and the burst strength were obtained for the obtained knitted fabric and the knitted fabric that had been subjected to shrink-proofing. The results are shown in Table 13.

[0408] [Table 13]

[0409] [Fabric manufacturing, shrink-proofing and evaluation] Using twisted yarn made of the modified fibroin fiber, four types of fabrics (Test Examples 4-5 to 4-8) were woven in a plain weave using a rapier loom (Evergreen Automatic Sampling Loom, manufactured by CCI) having different weaving densities as shown in Table 14 below. Here, the fineness of the twisted yarn made of the modified fibroin fiber was 190 d, and the twist number was 450 T / m.

[0410] The four types of woven fabrics obtained above were each immersed in water at 40°C for 10 minutes and then dried to perform a shrink-proofing treatment. Thereafter, the densities of the woven fabrics of Test Examples 4-5 to 4-8 were examined. The results are shown in Table 14 below. In the table, the weaving density is shown in the form of warp density multiplied by weft density. For example, a weaving density of "26 x 26" means a warp density of 26 (threads / in) and a weft density of 26 (threads / in).

[0411] Four types of woven fabrics having different densities as shown in Table 14 below (Test Examples 4-9 to 4-12) were woven in the same manner as above, except that twisted yarn made of polyamide fiber was used instead of the twisted yarn made of modified fibroin fiber. Here, the fineness of the twisted yarn made of polyamide fiber was 150 d, and the twist number was 150 T / m.

[0412] The fabrics of Test Examples 4-9 to 4-12 were subjected to shrink-proofing treatment in the same manner as above. Thereafter, the densities of the fabrics of Test Examples 4-9 to 4-12 were measured. The results are shown in Table 14 below.

[0413] [Table 14]

[0414] [Test Example 5: Production and evaluation of functionalized protein fibers] (Test Example 5-1) <Preparation of spinning solution (dope solution)> 200 mg of starch (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 11,400 mg of a solvent (dimethyl sulfoxide (DMSO) containing 4 wt% LiCl), and then 400 mg of phenyl isocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added thereto and stirred at 90°C for 4 hours to react. As a result, the hydroxyl groups of the starch reacted with the isocyanate groups of the phenyl isocyanate to obtain a modified starch (modified hydroxyl group-containing polymer) in which the phenyl groups (functional functional groups) were bonded via urethane bonds. The modification rate (the proportion of hydroxyl groups converted to functional functional groups) of the modified starch calculated from the charge ratio was 100%.

[0415] After cooling the reaction solution to room temperature, 300 mg of the modified fibroin (PRT799) powder obtained above was added to the reaction solution and dissolved by stirring at 90°C for 12 hours to obtain a transparent spinning solution. The content of modified starch in the spinning solution was 17% by mass based on the total content of modified starch and starch.

[0416] <Production of protein fibers> The prepared spinning solution was filtered at 60°C with a metal filter having an opening of 5 μm, then left to stand in a 30 mL stainless steel syringe and degassed, and then discharged from a solid nozzle having a needle diameter of 0.2 mm into a 100% by mass methanol coagulation bath using nitrogen gas. The discharge temperature was 60°C and the discharge pressure was 0.3 MPa. After coagulation, the obtained raw yarn was wound at a winding speed of 3.00 m / min and naturally dried to obtain protein fibers (modified fibroin fibers).

[0417] <Water shrinkage test> The obtained protein fiber was cut to a length of about 10 cm, and the length (cm) of the thread before immersion in water was measured. The thread was then immersed in a water bath at 40°C for 1 minute. The thread was then removed from the water bath and vacuum dried at room temperature for 15 minutes, after which the length of the thread after drying was measured. The water shrinkage of the protein fiber was calculated according to the following formula. Water shrinkage rate (%) = {(length before immersion / length after immersion and drying)-1} x 100

[0418] (Test Example 5-2) <Preparation of spinning solution (dope solution)> 253 mg of starch (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 7600 mg of solvent (dimethyl sulfoxide (DMSO) containing 4 wt% LiCl), and then 147 mg of acetic anhydride (manufactured by Wako Pure Chemical Industries, Ltd.) was added and reacted by stirring at 90°C for 4 hours. As a result, the hydroxyl groups of the starch reacted with the acetic anhydride to obtain modified starch (modified hydroxyl group-containing polymer) to which acetyl groups (functional functional groups) were bonded. The modification rate (the proportion of hydroxyl groups converted to functional functional groups) of the modified starch calculated from the feed ratio was 100%.

[0419] After cooling the reaction solution to room temperature, 2000 mg of the modified fibroin (PRT799) powder obtained above was added to the reaction solution and dissolved by stirring at 90°C for 12 hours to obtain a transparent spinning solution. The content of modified starch in the spinning solution was 17% by mass based on the total content of modified starch and starch.

[0420] <Production of protein fiber and water shrinkage test> Using the prepared spinning dope, protein fibers were produced and a water shrinkage test was carried out in the same manner as in Test Example 5-1.

[0421] (Test Example 5-3) <Preparation of spinning solution (dope solution)> 215 mg of starch (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 7600 mg of solvent (dimethyl sulfoxide (DMSO) containing 4 wt% LiCl), and then 185 mg of acetic anhydride (manufactured by Wako Pure Chemical Industries, Ltd.) was added and reacted by stirring at 90°C for 4 hours. As a result, the hydroxyl groups of the starch reacted with the acetic anhydride to obtain modified starch (modified hydroxyl group-containing polymer) to which acetyl groups (functional functional groups) were bonded. The modification rate (the proportion of hydroxyl groups converted to functional functional groups) of the modified starch calculated from the feed ratio was 50%.

[0422] After cooling the reaction solution to room temperature, 2000 mg of the modified fibroin (PRT799) powder obtained above was added to the reaction solution and dissolved by stirring at 90°C for 12 hours to obtain a transparent spinning solution. The content of modified starch in the spinning solution was 17% by mass based on the total content of modified starch and starch.

[0423] <Production of protein fiber and water shrinkage test> Using the prepared spinning dope, protein fibers were produced and a water shrinkage test was carried out in the same manner as in Test Example 5-1.

[0424] (Test Example 5-4) <Preparation of spinning solution (dope solution)> 128 mg of polyvinyl alcohol (PVA) (Wako Pure Chemical Industries, Ltd.) was dissolved in 7600 mg of solvent (dimethyl sulfoxide (DMSO) containing 4 wt% LiCl), and then 272 mg of phenyl isocyanate (Tokyo Chemical Industry Co., Ltd.) was added and reacted by stirring at 90°C for 4 hours. As a result, the hydroxyl groups of the PVA reacted with the phenyl isocyanate to obtain a modified PVA (modified hydroxyl group-containing polymer) in which the phenyl groups (functional functional groups) were bonded via urethane bonds. The modification rate (the ratio of hydroxyl groups converted to functional functional groups) of the modified PVA calculated from the charge ratio was 100%.

[0425] After cooling the reaction solution to room temperature, 2000 mg of the modified fibroin (PRT799) powder obtained above was added to the reaction solution and dissolved by stirring at 90°C for 12 hours to obtain a transparent spinning solution. The content of modified PVA in the spinning solution was 17 mass% based on the total content of modified PVA and PVA.

[0426] <Production of protein fiber and water shrinkage test> Using the prepared spinning dope, protein fibers were produced and a water shrinkage test was carried out in the same manner as in Test Example 5-1.

[0427] (Test Example 5-5) <Preparation of spinning solution (dope solution)> 193 mg of polyvinyl alcohol (PVA) (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 7600 mg of a solvent (dimethyl sulfoxide (DMSO) containing 4 wt% LiCl), and then 207 mg of phenyl isocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added thereto and reacted by stirring at 90°C for 4 hours. As a result, the hydroxyl groups of the PVA reacted with the phenyl isocyanate to obtain a modified PVA (modified hydroxyl group-containing polymer) in which the phenyl groups (functional functional groups) were bonded via urethane bonds. The modification rate (the ratio of hydroxyl groups converted to functional functional groups) of the modified PVA calculated from the charge ratio was 50%.

[0428] After cooling the reaction solution to room temperature, 2000 mg of the modified fibroin (PRT799) powder obtained above was added to the reaction solution and dissolved by stirring at 90°C for 12 hours to obtain a transparent spinning solution. The content of modified PVA in the spinning solution was 17 mass% based on the total content of modified PVA and PVA.

[0429] <Production of protein fiber and water shrinkage test> Using the prepared spinning dope, protein fibers were produced and a water shrinkage test was carried out in the same manner as in Test Example 5-1.

[0430] (Test Example 5-6) <Preparation of spinning solution (dope solution)> 1,200 mg of the modified fibroin (PRT799) powder obtained above was added to a solvent (dimethyl sulfoxide (DMSO) containing 4 wt% LiCl) and dissolved by stirring at 90°C for 12 hours to obtain a transparent spinning solution.

[0431] <Production of protein fiber and water shrinkage test> Using the prepared spinning dope, protein fibers were produced and a water shrinkage test was carried out in the same manner as in Test Example 5-1.

[0432] (Test Example 5-7) <Preparation of spinning solution (dope solution)> 3,000 mg of the modified fibroin (PRT799) powder obtained above and 600 mg of starch (manufactured by Wako Pure Chemical Industries, Ltd.) were added to a solvent (dimethyl sulfoxide (DMSO) containing 4 wt% LiCl) and dissolved by stirring at 90°C for 12 hours to obtain a transparent spinning solution.

[0433] <Production of protein fiber and water shrinkage test> Using the prepared spinning dope, protein fibers were produced and a water shrinkage test was carried out in the same manner as in Test Example 5-1.

[0434] The results are shown in Figure 7 and Table 15. In Table 15, Test Example 3-1 refers to the above Test Example 5-1, Test Example 3-2 refers to the above Test Example 5-2, Test Example 3-3 refers to the above Test Example 5-3, Test Example 3-4 refers to the above Test Example 5-4, Test Example 3-5 refers to the above Test Example 5-5, Test Example 3-6 refers to the above Test Example 5-6, and Test Example 3-7 refers to the above Test Example 5-7. [Table 15]

[0435] By producing protein fibers using a spinning dope containing a modified hydroxyl group-containing polymer (modified starch or modified PVA) to which a hydrophobic functional group (phenyl group or acetyl group) is bonded as a functional group, and a protein (modified fibroin) (Test Examples 5-1 to 5-5 (Test Examples 3-1 to 3-5 in Table 15)), water shrinkage was reduced and water-resistant protein fibers were obtained compared to the case where a spinning dope containing only protein was used (Test Example 5-6 (Test Example 3-6 in Table 15)) and the case where a spinning dope containing protein and an unmodified hydroxyl group-containing polymer was used (Test Example 5-7 (Test Example 3-7 in Table 15)). By knitting or weaving a knitted or woven fabric using these protein fibers, a knitted or woven fabric having functionality (water resistance) can be obtained.

[0436] [Test Example 6: Production and evaluation of functionalized protein fibers] (Production Example 1) The above-mentioned spider silk fibroin (PRT799) 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 spider silk fibroin was then dissolved using a shaker for 3 hours to obtain a DMSO solution. Dust and bubbles were removed from the obtained DMSO solution to obtain a dope solution. The solution viscosity of the dope solution was 5000 cP (centipoise) at 90°C.

[0437] The dope solution obtained as described above was used in a known dry-wet spinning apparatus to perform dry-wet spinning to obtain a monofilament made of spider silk fibroin. The dry-wet spinning was performed under the following conditions. Temperature of coagulation liquid (methanol): 5-10℃ Stretching ratio: 6x Drying temperature: 80℃

[0438] The modified spider silk fibroin fiber thus obtained was used to produce a spun yarn by a known method, and the spun yarn made of the modified spider silk fibroin fiber was used to knit a 5 cm square knitted fabric (woven fabric) by weft knitting using a known knitting machine. The count of the spun yarn made of the modified spider silk fibroin fiber was 58.1 Nm, and the gauge number of the knitting machine was 18.

[0439] (Test Example 6-1) The woven fabric (5 cm square) obtained in Production Example 1 was immersed in 20 mL of hexane diisocyanate (HDI). Next, the woven fabric impregnated with HDI was sandwiched between aluminum foil and heated at 130°C for 30 minutes. After heating, the woven fabric was removed, immersed in 20 mL of butanol (BuOH), and reacted at 100°C for 240 minutes. After the reaction, the test sample was washed with THF to obtain a woven fabric imparted with functionality (water resistance imparting substance (first reactant and second reactant) bonded).

[0440] (Test Example 6-2) The knitted fabric obtained in Production Example 1 was evaluated as the knitted fabric of Test Example 6-2.

[0441] (Test Example 6-3) The woven fabric obtained in Production Example 1 was immersed in 20 mL of hexane diisocyanate (HDI, first reactant). Next, the HDI-impregnated woven fabric was sandwiched between aluminum foil and heated at 130°C for 30 minutes. After that, the woven fabric was washed with THF to obtain a woven fabric of Test Example 6-3 in which only the first reactant was bonded.

[0442] The knitted and woven fabrics of Test Examples 6-1 to 6-3 were evaluated for water resistance (shrinkage) and texture by the following test methods.

[0443] <Water resistance (shrinkage) evaluation> A 3 cm square was drawn on the knitted fabric with a pencil to prepare an evaluation sample. The evaluation sample was washed in a Panasonic washing machine (Na-VG1100L) using the "Home Cleaning" washing mode. The sample was then dehydrated for 15 minutes in the same washing machine and air-dried for 120 minutes. The length and width of the square were measured before and after washing, and the shrinkage rates in the longitudinal and transverse directions were calculated. The same test was performed three times, and the average value of the three results was used as the evaluation result. The results are shown in Table 16. In Table 16, Test Example 4-1 indicates Test Example 6-1, Test Example 4-2 indicates Test Example 6-2, and Test Example 4-3 indicates Test Example 6-3.

[0444] <Texture evaluation> The texture of the woven fabric was evaluated on a three-point scale. The texture of the woven fabric in Test Example 6-2 was set as the standard (B), and woven fabrics with a better texture were rated as A, and woven fabrics with a rough texture and poor texture were rated as C. The results are shown in Table 16.

[0445] [Table 16]

[0446] [Test Example 7: Production and evaluation of woven fabric using modified fibroin fibers] (1) Preparation of spinning solution (dope solution) DMSO in which lithium chloride was dissolved to a concentration of 4% by mass was used as a solvent, and the freeze-dried powder of the modified fibroin (PRT799) produced above was added to the solvent to a concentration of 24% by mass. After dissolving for 1 hour in an aluminum block heater at 90°C, insoluble matter and bubbles were removed to obtain a spinning solution (dope solution).

[0447] (2) Spinning The spinning solution was filled into a reserve tank and discharged from a monohole nozzle with a diameter of 0.1 or 0.2 mm into a 100% by mass methanol coagulation bath using a gear pump. The discharge rate was adjusted to 0.01 to 0.08 mL / min. After coagulation, washing and drawing were performed in a 100% by mass methanol washing bath. After washing and drawing, the fiber was dried using a dry heat plate, and the obtained raw yarn (modified fibroin fiber) was wound up.

[0448] (3) Manufacture of woven fabrics The modified fibroin fibers were then used to make ply-ply yarns, which were then plain woven to obtain woven fabrics.

[0449] (4) Bonding of water-resistant substances to woven fabrics The obtained woven fabric was coated with a fluorine-based coating monomer and subjected to plasma treatment using a plasma treatment device (manufactured by Europlasma). The plasma treatment resulted in a woven fabric with a fluorine-based polymer (water resistance imparting substance) covalently bonded to the fluorine-based coating monomer. Nanofics110 (Test Example 7-2) and Nanofics120 (Test Example 7-3) (both manufactured by Europlasma) were used as the fluorine-based coating monomer.

[0450] (5) Water repellency evaluation A water repellency test (spray test) was conducted on the woven fabrics of Test Examples 7-2 and 7-3 that were subjected to plasma treatment, and on the woven fabric (Test Example 7-1) that was not subjected to plasma treatment. The water repellency test (spray test) was conducted in accordance with ISO4920:2012. Judgment was conducted visually according to the following 6-level evaluation criteria (score 0 to 5). Score 5: No wetting or water droplets on the surface. Score 4: The surface is not wetted, but water droplets are attached. Score 3: There is a small amount of wetting on the surface. Score 2: The infiltration is widespread and some are connected to each other. Score 1: indicates complete wetting of the area hit by the water. Score 0: The entire surface is wet.

[0451] The results are shown in Table 17. The woven fabric of Test Example 7-1, which was not subjected to plasma treatment, received a score of 0, whereas the woven fabrics of Test Examples 7-2 and 7-3, which were subjected to plasma treatment, both received a score of 4, and were imparted with water resistance (water repellency). In Tables 17, 18, and 19 below, Test Example 2-1 refers to the above Test Example 7-1, Test Example 2-2 refers to the above Test Example 7-2, and Test Example 2-3 refers to the above Test Example 7-3, respectively.

[0452] [Table 17]

[0453] (6) Evaluation of texture and shrinkage A square test piece with a side length of 5 cm was cut out from each of the woven fabrics of Test Examples 7-1 to 7-3. The vertices (four points) of a square with a side length of 30 mm were marked with a pencil on one surface of the test piece. Each test piece was immersed in water at 40°C for 10 minutes, and then vacuum dried at room temperature. This process was repeated five times. The vacuum drying was performed for 30 minutes using a vacuum constant temperature dryer (VOS-310C, manufactured by Tokyo Rikakikai Co., Ltd.) at a set pressure of -0.1 MPa. In addition, at the end of each cycle, the tactile sensation was evaluated, and the shrinkage rate was evaluated by measuring the distance between the four marked points.

[0454] The texture was evaluated according to the following criteria. The results are shown in Table 18. The woven fabrics of Test Example 7-2 and Test Example 7-3, which were subjected to plasma treatment, showed less deterioration in texture than the woven fabric of Test Example 7-1, which was not subjected to plasma treatment. Score 5: As good as the original. Score 4: Good, but slightly inferior to the original. Score 3: Not bad, but a bit hard. Score 2: Poor and stiff, but bendable. Score 1: Very bad, stiff and inflexible.

[0455] [Table 18]

[0456] The shrinkage rate was calculated according to the following formula: The "average length of each side" is the sum of the lengths of each side of the rectangle formed by the four marked points divided by four. Shrinkage rate (%) = {1-(average length of each side (mm) / 30mm)} x 100 The results are shown in Table 19. The woven fabrics of Test Example 2-2 and Test Example 7-3, which were subjected to plasma treatment, both had smaller shrinkage percentages than the woven fabric of Test Example 7-1, which was not subjected to plasma treatment.

[0457] [Table 19]

[0458] [Test Example 8: Production and evaluation of knitted fabric using modified fibroin fiber] (1) Preparation of spinning solution (dope solution) DMSO in which lithium chloride was dissolved to a concentration of 4% by mass was used as a solvent, and the freeze-dried powder of the modified fibroin (PRT918) produced above was added to the solvent to a concentration of 24% by mass. After dissolving for 1 hour in an aluminum block heater at 90°C, insoluble matter and bubbles were removed to obtain a spinning solution (dope solution).

[0459] (2) Spinning The spinning solution was filled into a reserve tank and discharged from a monohole nozzle with a diameter of 0.1 or 0.2 mm into a 100% by mass methanol coagulation bath using a gear pump. The discharge rate was adjusted to 0.01 to 0.08 mL / min. After coagulation, washing and drawing were performed in a 100% by mass methanol washing bath. After washing and drawing, the fiber was dried using a dry heat plate, and the obtained raw yarn (modified fibroin fiber) was wound up.

[0460] (3) Manufacturing knitted fabric for evaluation The modified fibroin fibers obtained were cut to produce modified fibroin staples. The modified fibroin staples thus produced were opened and then spun using a known spinning device to produce spun yarn. The spun yarn was knitted using a whole garment flat knitting machine (MACH2XS, manufactured by Shima Seiki Co., Ltd.) to produce a knitted fabric.

[0461] (4) Bonding of water-resistant substances to knitted fabrics The obtained knitted fabric was coated with a fluorine-based coating monomer and subjected to plasma treatment using a plasma treatment device (manufactured by Europlasma). The plasma treatment resulted in a knitted fabric with a fluorine-based polymer (water resistance imparting substance) covalently bonded to the fluorine-based coating monomer (Test Example 3-2). Nanofics120 (manufactured by Europlasma) was used as the fluorine-based coating monomer.

[0462] (5) Water repellency evaluation A water repellency test (spray test) was conducted on the knitted fabric of Test Example 8-2 that was subjected to plasma treatment and the knitted fabric (Test Example 8-1) that was not subjected to plasma treatment in the same manner as in Test Example 7. The results are shown in Table 20. The knitted fabric of Test Example 8-1 that was not subjected to plasma treatment received a score of 0, whereas the knitted fabric of Test Example 8-2 that was subjected to plasma treatment received a score of 5, and was imparted with water resistance (water repellency). In the following Tables 20, 21, and 22, Test Example 3-1 refers to the above Test Example 8-1, and Test Example 3-2 refers to the above Test Example 8-2, respectively. [Table 20]

[0463] (6) Evaluation of texture and shrinkage Square test pieces with sides of 5 cm were cut out from the knitted fabrics of Test Examples 8-1 and 8-2. Four vertices of a square with sides of 30 mm were marked with a pencil on one surface of the test pieces. As a preliminary treatment, each test piece was immersed in water at 40°C for 10 minutes, and then vacuum dried at room temperature for five cycles. Vacuum drying was performed for 30 minutes using a vacuum constant temperature dryer (VOS-310C, manufactured by Tokyo Rikakikai Co., Ltd.) at a set pressure of -0.1 MPa.

[0464] Next, the test piece that had undergone the preliminary treatment was subjected to five cycles of washing, drying, soaking, and drying in this order. In the washing process, a Panasonic washing machine (NA-VG1100L) was used, and the test piece was washed for five minutes using a Lion detergent (Top Clear Liquid), rinsed twice, and then dehydrated for one minute. In the drying process, a vacuum constant temperature dryer (VOS-310C, Tokyo Rikakikai Co., Ltd.) was used to dry the test piece at room temperature for 30 minutes at a set pressure of -0.1 MPa. In the soaking process, the test piece was immersed in water at 40°C for 10 minutes. At the end of each cycle, the tactile sensation was evaluated using the same criteria as in Test Example 7, and the shrinkage rate was evaluated by measuring the distance between the four marked points.

[0465] The sensory evaluation results for the touch are shown in Table 21. Note that "at the start" is the evaluation result after the preliminary treatment and before the cycle was started. The knitted fabric of Test Example 8-2 (Test Example 2-2 in Table 21) which was subjected to plasma treatment showed less deterioration in touch than the knitted fabric of Test Example 8-1 (Test Example 2-1 in Table 21) which was not subjected to plasma treatment. [Table 21]

[0466] The evaluation results of the shrinkage rate are shown in Table 22. The knitted fabric of Test Example 8-2 (Test Example 2-2 in Table 22), which was subjected to plasma treatment, had a smaller shrinkage rate than the knitted fabric of Test Example 8-1 (Test Example 2-1 in Table 22), which was not subjected to plasma treatment. [Table 22]

[0467] Test Example 9: Production and evaluation of modified fibroin fibers <Test Example 9-1> (1) Preparation of spinning solution (dope solution) 200 mg of starch (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 11,400 mg of a solvent (dimethyl sulfoxide (DMSO) containing 4 wt% LiCl), and then 400 mg of phenyl isocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added thereto and stirred at 90°C for 4 hours to react. As a result, the hydroxyl groups of the starch reacted with the isocyanate groups of the phenyl isocyanate to obtain a modified starch (modified hydroxyl group-containing polymer) in which the phenyl groups (functional functional groups) were bonded via urethane bonds. The modification rate (the proportion of hydroxyl groups converted to functional functional groups) of the modified starch calculated from the charge ratio was 100%.

[0468] After the reaction solution was cooled to room temperature, 300 mg of freeze-dried powder of modified fibroin (PRT799) was added to the reaction solution and dissolved by stirring at 90°C for 12 hours to obtain a transparent spinning solution (dope solution). The content of modified starch in the spinning solution was 17% by mass based on the total content of modified starch and starch.

[0469] (2) Production of fibers containing modified fibroin and a substance that provides water resistance The prepared spinning solution was filtered at 60°C through a metal filter with a mesh size of 5 μm, then left to stand in a 30 mL stainless steel syringe and degassed, after which it was discharged from a solid nozzle with a needle diameter of 0.2 mm into a 100% by mass methanol coagulation bath using nitrogen gas. The discharge temperature was 60°C and the discharge pressure was 0.3 MPa. After solidification, the obtained raw yarn was wound at a winding speed of 3.00 m / min and naturally dried to obtain a fiber containing modified fibroin and a water resistance imparting substance (modified starch).

[0470] (3) Contractility evaluation The obtained fibers were cut to a length of about 10 cm, and the length (cm) of the yarn before immersion in water was measured. The yarn was then immersed in a water bath at 40°C for 1 minute. The yarn was then removed from the water bath and vacuum dried at room temperature for 15 minutes, after which the length of the dried yarn was measured. The shrinkage of the fiber was calculated according to the following formula. The results are shown in Table 23. Shrinkage rate (%) = {(length before immersion / length after immersion and drying)-1} x 100 In Table 23, Test Example 5-1 indicates Test Example 9-1, Test Example 5-2 indicates Test Example 9-2 described later, Test Example 5-3 indicates Test Example 9-3 described later, Test Example 5-4 indicates Test Example 9-4 described later, Test Example 5-5 indicates Test Example 9-5 described later, Test Example 5-6 indicates Test Example 9-6 described later, and Test Example 5-7 indicates Test Example 9-7 described later.

[0471] <Test Example 9-2> (1) Preparation of spinning solution (dope solution) 253 mg of starch (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 7600 mg of solvent (dimethyl sulfoxide (DMSO) containing 4 wt% LiCl), and then 147 mg of acetic anhydride (manufactured by Wako Pure Chemical Industries, Ltd.) was added and reacted by stirring at 90°C for 4 hours. As a result, the hydroxyl groups of the starch reacted with the acetic anhydride to obtain modified starch (modified hydroxyl group-containing polymer) to which acetyl groups (functional functional groups) were bonded. The modification rate (the proportion of hydroxyl groups converted to functional functional groups) of the modified starch calculated from the feed ratio was 100%.

[0472] After the reaction solution was cooled to room temperature, 2000 mg of freeze-dried powder of modified fibroin (PRT799) was added to the reaction solution and dissolved by stirring at 90°C for 12 hours to obtain a transparent spinning solution (dope solution). The content of modified starch in the spinning solution was 17% by mass based on the total content of modified starch and starch.

[0473] (2) Production of fibers containing modified fibroin and a substance that provides water resistance Using the prepared spinning solution, a fiber containing modified fibroin and a water resistance imparting substance (modified starch) was obtained in the same manner as in Test Example 9-1.

[0474] (3) Contractility evaluation The shrinkage properties of the obtained fiber were evaluated in the same manner as in Test Example 9-1. The results are shown in Table 23.

[0475] <Test Example 9-3> (1) Preparation of spinning solution (dope solution) 215 mg of starch (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 7600 mg of solvent (dimethyl sulfoxide (DMSO) containing 4 wt% LiCl), and then 185 mg of acetic anhydride (manufactured by Wako Pure Chemical Industries, Ltd.) was added and reacted by stirring at 90°C for 4 hours. As a result, the hydroxyl groups of the starch reacted with the acetic anhydride to obtain modified starch (modified hydroxyl group-containing polymer) to which acetyl groups (functional functional groups) were bonded. The modification rate (the proportion of hydroxyl groups converted to functional functional groups) of the modified starch calculated from the feed ratio was 50%.

[0476] After the reaction solution was cooled to room temperature, 2000 mg of freeze-dried powder of modified fibroin (PRT799) was added to the reaction solution and dissolved by stirring at 90°C for 12 hours to obtain a transparent spinning solution (dope solution). The content of modified starch in the spinning solution was 17% by mass based on the total content of modified starch and starch.

[0477] (2) Production of fibers containing modified fibroin and a substance that provides water resistance Using the prepared spinning solution, a fiber containing modified fibroin and a water resistance imparting substance (modified starch) was obtained in the same manner as in Test Example 5-1.

[0478] (3) Contractility evaluation The shrinkage properties of the obtained fiber were evaluated in the same manner as in Test Example 9-1. The results are shown in Table 23.

[0479] <Test Example 9-4> (1) Preparation of spinning solution (dope solution) 128 mg of polyvinyl alcohol (PVA) (Wako Pure Chemical Industries, Ltd.) was dissolved in 7600 mg of solvent (dimethyl sulfoxide (DMSO) containing 4 wt% LiCl), and then 272 mg of phenyl isocyanate (Tokyo Chemical Industry Co., Ltd.) was added and reacted by stirring at 90°C for 4 hours. As a result, the hydroxyl groups of the PVA reacted with the phenyl isocyanate to obtain a modified PVA (modified hydroxyl group-containing polymer) in which the phenyl groups (functional functional groups) were bonded via urethane bonds. The modification rate (the ratio of hydroxyl groups converted to functional functional groups) of the modified PVA calculated from the charge ratio was 100%.

[0480] After cooling the reaction solution to room temperature, 2000 mg of freeze-dried powder of modified fibroin (PRT799) was added to the reaction solution and dissolved by stirring at 90°C for 12 hours to obtain a transparent spinning solution (dope solution). The content of modified PVA in the spinning solution was 17% by mass based on the total content of modified PVA and PVA.

[0481] (2) Production of fibers containing modified fibroin and a substance that provides water resistance Using the prepared spinning solution, a fiber containing modified fibroin and a water resistance imparting substance (modified PVA) was obtained in the same manner as in Test Example 9-1.

[0482] (3) Contractility evaluation The shrinkage properties of the obtained fiber were evaluated in the same manner as in Test Example 9-1. The results are shown in Table 23.

[0483] <Test Example 9-5> (1) Preparation of spinning solution (dope solution) 193 mg of polyvinyl alcohol (PVA) (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 7600 mg of a solvent (dimethyl sulfoxide (DMSO) containing 4 wt% LiCl), and then 207 mg of phenyl isocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added thereto and reacted by stirring at 90°C for 4 hours. As a result, the hydroxyl groups of the PVA reacted with the phenyl isocyanate to obtain a modified PVA (modified hydroxyl group-containing polymer) in which the phenyl groups (functional functional groups) were bonded via urethane bonds. The modification rate (the ratio of hydroxyl groups converted to functional functional groups) of the modified PVA calculated from the charge ratio was 50%.

[0484] After cooling the reaction solution to room temperature, 2000 mg of freeze-dried powder of modified fibroin (PRT799) was added to the reaction solution and dissolved by stirring at 90°C for 12 hours to obtain a transparent spinning solution (dope solution). The content of modified PVA in the spinning solution was 17% by mass based on the total content of modified PVA and PVA.

[0485] (2) Production of fibers containing modified fibroin and a substance that provides water resistance Using the prepared spinning solution, a fiber containing modified fibroin and a water resistance imparting substance (modified PVA) was obtained in the same manner as in Test Example 9-1.

[0486] (3) Contractility evaluation The shrinkage properties of the obtained fiber were evaluated in the same manner as in Test Example 9-1. The results are shown in Table 23.

[0487] <Test Example 9-6> (1) Preparation of spinning solution (dope solution) 1,200 mg of freeze-dried powder of modified fibroin (PRT799) was added to a solvent (dimethyl sulfoxide (DMSO) containing 4 wt % LiCl) and dissolved by stirring at 90°C for 12 hours to obtain a transparent spinning solution (dope solution).

[0488] (2) Textile manufacturing Using the prepared spinning solution, fibers were obtained in the same manner as in Test Example 9-1.

[0489] (3) Contractility evaluation The shrinkage properties of the obtained fiber were evaluated in the same manner as in Test Example 9-1. The results are shown in Table 23.

[0490] <Test Example 9-7> (1) Preparation of spinning solution (dope solution) 3,000 mg of freeze-dried powder of modified fibroin (PRT799) and 600 mg of starch (Wako Pure Chemical Industries, Ltd.) were added to a solvent (dimethyl sulfoxide (DMSO) containing 4 wt% LiCl) and dissolved by stirring at 90°C for 12 hours to obtain a transparent spinning solution (dope solution).

[0491] (2) Textile manufacturing Using the prepared spinning solution, fibers were obtained in the same manner as in Test Example 9-1.

[0492] (3) Contractility evaluation The shrinkage properties of the obtained fiber were evaluated in the same manner as in Test Example 9-1. The results are shown in Table 23.

[0493] [Table 23]

[0494] Fibers containing modified fibroin and a substance that provides water resistance (a hydroxyl-containing polymer (modified starch or modified PVA)) had reduced shrinkage compared to fibers without the substance that provides water resistance.

[0495] [Test Example 10: Evaluation of flame retardancy of modified fibroin fiber] Dimethyl sulfoxide (DMSO) in which LiCl was dissolved to a concentration of 4.0 mass% was prepared as a solvent, and freeze-dried powder of modified fibroin (PRT799) was added to the solvent to a concentration of 24 mass%, and dissolved for 3 hours using a shaker. Insoluble matter and bubbles were then removed to obtain a modified fibroin solution (spinning stock solution).

[0496] The prepared spinning solution was filtered through a metal filter with a mesh size of 5 μm at 90° C., then allowed to stand in a 30 mL stainless steel syringe and degassed, and then discharged from a solid nozzle with a needle diameter of 0.2 mm into a 100% by mass methanol coagulation bath. The discharge temperature was 90° C. After coagulation, the obtained raw yarn was wound and naturally dried to obtain a modified fibroin fiber.

[0497] The resulting modified fibroin fiber (twisted filament yarn) was used to produce a knitted fabric for evaluation by circular knitting using a circular knitting machine. The knitted fabric had a thickness of 180 denier and a gauge number of 18. 20 g of the resulting knitted fabric was cut out as a test specimen.

[0498] The flammability test was conducted in accordance with the test method for powdered or low melting point synthetic resins issued by the Director of the Hazardous Materials Control Division of the Fire and Disaster Management Agency, ...

[0499] [Table 24]

[0500] As a result of the flame retardancy test, the limiting oxygen index (LOI) value of the modified fibroin (PRT799) fiber was 27.2. Generally, an LOI value of 26 or higher is considered to be flame retardant. This shows that the modified fibroin fiber has excellent flame retardancy.

[0501] [Test Example 11: Evaluation of moisture absorption and heat generation properties of modified fibroin fiber] Dimethyl sulfoxide (DMSO) in which LiCl was dissolved to a concentration of 4.0% by mass was prepared as a solvent, and the freeze-dried powder of modified fibroin was added to the solvent to a concentration of 24% by mass, and dissolved for 3 hours using a shaker. Insoluble matter and bubbles were then removed to obtain a modified fibroin solution (spinning stock solution).

[0502] The prepared spinning solution was filtered at 60°C through a metal filter with a mesh size of 5 μm, then left to stand in a 30 mL stainless steel syringe to degas it, and then discharged from a solid nozzle with a needle diameter of 0.2 mm into a 100% by mass methanol coagulation bath. The discharge temperature was 60°C. After coagulation, the obtained raw yarn was wound and naturally dried to obtain a modified fibroin fiber.

[0503] For comparison, commercially available wool fibers, cotton fibers, Tencel fibers, rayon fibers and polyester fibers were prepared.

[0504] Using each fiber, knitted fabrics for evaluation were produced by flat knitting using a flat knitting machine. The knitted fabrics using modified fibroin (PRT918) fiber had a thickness of 1 / 30N (single wool count) and a gauge number of 18. The knitted fabrics using modified fibroin (PRT799) fiber had a thickness of 1 / 30N (single wool count) and a gauge number of 16. The knitted fabrics using other fibers were adjusted in thickness and gauge number so that they had almost the same cover factor as the knitted fabrics using PRT918 fiber and PRT799 fiber. Specifically, the thickness and gauge number were as follows. Wool Thickness: 2 / 30N (double thread), Gauge: 14 Cotton Thickness: 2 / 34N (double thread), Gauge: 14 Tencel Thickness: 2 / 30N (double thread), Gauge: 15 Rayon Thickness: 1 / 38N (single thread), Gauge: 14 Polyester Thickness: 1 / 60N (single thread), Gauge: 14

[0505] Two pieces of knitted fabric cut to 10cm x 10cm were put together and sewn together at all four sides to make a test piece (sample). The test piece was left in a low humidity environment (temperature 20±2°C, relative humidity 40±5%) for more than 4 hours, then transferred to a high humidity environment (temperature 20±2°C, relative humidity 90±5%), and the temperature was measured at 1-minute intervals for 30 minutes using a temperature sensor attached to the center inside the test piece.

[0506] From the measurement results, the maximum moisture absorption heat generation was calculated according to the following formula A. Formula A: Maximum moisture absorption heat release rate = {(Maximum sample temperature when the sample is placed in a low humidity environment until the sample temperature reaches equilibrium and then transferred to a high humidity environment) - (sample temperature when the sample is placed in a low humidity environment until the sample temperature reaches equilibrium and then transferred to a high humidity environment)} (°C) / sample weight (g)

[0507] FIG. 8 is a graph showing an example of the results of a moisture absorption heat generation test. The horizontal axis of the graph indicates the time (minutes) that the sample was left in the high humidity environment, with the point at which the sample was moved from a low humidity environment to a high humidity environment being set at 0. The vertical axis of the graph indicates the temperature (sample temperature) measured by the temperature sensor. In the graph shown in FIG. 8, the point indicated by M corresponds to the maximum sample temperature. The calculation results of the maximum moisture absorption heat generation are shown in Table 25.

[0508] [Table 25]

[0509] As shown in Table 25, the modified fibroin fibers (PRT918 fiber and PRT799 fiber) have a higher maximum moisture absorption heat generation rate and are superior in moisture absorption and heat generation properties compared to existing fibers.

[0510] [Test Example 12: Evaluation of heat retention of modified fibroin fiber] Dimethyl sulfoxide (DMSO) in which LiCl was dissolved to a concentration of 4.0% by mass was prepared as a solvent, and the freeze-dried powder of modified fibroin was added to the solvent to a concentration of 24% by mass, and dissolved for 3 hours using a shaker. Insoluble matter and bubbles were then removed to obtain a modified fibroin solution (spinning stock solution).

[0511] The prepared spinning solution was filtered at 60°C through a metal filter with a mesh size of 5 μm, then left to stand in a 30 mL stainless steel syringe to degas it, and then discharged from a solid nozzle with a needle diameter of 0.2 mm into a 100% by mass methanol coagulation bath. The discharge temperature was 60°C. After coagulation, the obtained raw yarn was wound and naturally dried to obtain a modified fibroin fiber.

[0512] For comparison, commercially available wool fibers, silk fibers, cotton fibers, rayon fibers and polyester fibers were prepared.

[0513] Each fiber was used to produce knitted fabrics for evaluation by flat knitting using a flat knitting machine. The knitted fabric using the modified fibroin (PRT966) fiber had a count of 30 Nm, twist count of 1, gauge of 18GG, and weight of 90.1 g / m 2 The knitted fabric using modified fibroin (PRT799) fiber had a count of 30 Nm, twist count of 1, gauge number GG: 16, and weight per unit area of ​​111.0 g / m 2 The thickness and gauge of the knitted fabrics using other fibers were adjusted so that the cover factor was almost the same as that of the knitted fabrics using PRT966 and PRT799 fibers. Specifically, the thickness and gauge were adjusted as follows. Wool count: 30Nm, twist count: 2, gauge: 14GG, weight: 242.6g / m 2 Silk count: 60Nm, twist count: 2, gauge: 14GG, weight: 225.2g / m 2 Cotton count: 34Nm, twist count: 2, gauge: 14GG, weight: 194.1g / m 2 Rayon, count: 38Nm, twist: 1, gauge: 14GG, weight: 181.8g / m 2 Polyester Count: 60Nm, Twist: 1, Gauge: 14GG, Weight: 184.7g / m 2

[0514] The heat retention was evaluated using a KES-F7 Thermo Lab II tester manufactured by Kato Tech Co., Ltd., using the dry contact method (a method that assumes direct contact between the skin and clothing in a dry state). A piece of knitted fabric cut to 20 cm x 20 cm was used as the test piece (sample). The test piece was set on a hot plate set at a constant temperature (30°C), and the amount of heat (a) dissipated through the test piece was determined under the condition of a wind speed of 30 cm / sec in a wind tunnel. The amount of heat (b) dissipated under the same conditions as above was determined without the test piece being set, and the heat retention rate (%) was calculated according to the following formula. Heat retention rate (%)=(1-a / b)×100

[0515] From the measurement results, the heat retention index was calculated according to the following formula B. Formula B: Heat retention index = Heat retention rate (%) / Sample weight (g / m 2 )

[0516] The results of calculating the heat retention index are shown in Table 26. The higher the heat retention index, the better the material's heat retention properties can be evaluated.

[0517] [Table 26]

[0518] As shown in Table 26, the modified fibroin fibers (PRT966 fiber and PRT799 fiber) have a higher thermal insulation index and are superior in thermal insulation properties compared to existing fibers.

[0519] [Test Example 13: Production of artificial fur] A freeze-dried powder of modified fibroin (PRT966) was added to formic acid to a concentration of 30% by mass, and dissolved for 1.5 hours using a dissolving tank with stirring blades. Insoluble matter and bubbles were then removed to obtain a modified fibroin solution (spinning stock solution). The modified spider silk fibroin solution obtained was used as a dope solution (spinning stock solution), and modified spider silk fibroin fibers (filaments) were produced by dry-wet spinning using a known dry-wet spinning device. Next, the modified fibroin fibers obtained were mechanically crimped using a known crimping device, and then cut to a length of 110 to 150 mm to obtain staples. The resulting staples were used to obtain spun yarn in a conventional manner. The resulting spun yarn was then used to obtain a pile knit fabric with pile protruding on one side by pile knitting. The pile loops were then cut and combed. As a result, an artificial fur made of modified fibroin fibers was obtained. Photographs of the obtained artificial fur are shown in Figures 9 and 10.

Claims

1. Contains artificial protein fibers, 1. An artificial fur, wherein the artificial protein fibers comprise modified fibroin fibers.

2. The artificial fur of claim 1 , wherein the modified fibroin fibers comprise modified spider silk fibroin fibers.

3. Contains shrink-proof protein fibers, 1. An artificial fur, wherein the protein fibers comprise modified fibroin fibers.

4. The artificial fur according to claim 3, wherein the protein fiber has a wet shrinkage rate of 2% or more as defined by the following formula I: Wet shrinkage rate={1-(length of protein fiber wetted by contacting with water / length of protein fiber after spinning and before contacting with water)}×100(%) (Equation I)

5. The artificial fur according to claim 3 or 4, wherein the protein fiber has a dry shrinkage rate, as defined by the following formula II, of more than 7%. Dry shrinkage rate={1-(length of protein fiber immersed in water to make it wet and then dried / length of protein fiber after spinning and before contact with water)}×100(%) (Equation II)

6. The artificial fur according to any one of claims 3 to 5, wherein the modified fibroin is modified spider silk fibroin.

7. The material contains fibers and has functionality, 1. An artificial fur, wherein said fibers comprise modified fibroin fibers.

8. Contains a protein crosslinker, the protein crosslinked product has a polypeptide backbone, a first residue which is a residue of a first reactant having two or more first reactive groups capable of reacting with a protein to form a bond, and a second residue which is a residue of a second reactant having one second reactive group capable of reacting with the first reactive group to form a bond, at least one of the first residues bridges the polypeptide backbone; 8. The artificial fur of claim 7, wherein at least one of the first residues is attached to the polypeptide backbone at one end and to the second residue at the other end.

9. 9. The artificial fur according to claim 7 or 8, comprising a modified hydroxyl group-containing polymer in which a functional group is bonded to a hydroxyl group-containing polymer.

10. The material includes fibers and a water resistance imparting material, 1. An artificial fur, wherein said fibers comprise modified fibroin fibers.

11. 11. The artificial fur of claim 10, wherein said fibers and said water-resistant substance are covalently bonded.

12. 12. The artificial fur according to claim 10, wherein the water-resistance imparting substance is at least one selected from the group consisting of silicone-based polymers and fluorine-based polymers.

13. The artificial fur according to any one of claims 10 to 12, wherein the modified fibroin is modified spider silk fibroin.

14. The artificial fur according to any one of claims 1 to 13, which has a limiting oxygen index (LOI) value of 26.0 or more.

15. The artificial fur according to any one of claims 1 to 14, wherein the maximum moisture absorption heat generation rate calculated according to the following formula A is more than 0.025°C / g. Formula A: Maximum moisture absorption heat generation rate={(maximum temperature of a sample when the sample is placed in a low humidity environment until the sample temperature reaches equilibrium and then transferred to a high humidity environment)−(temperature of a sample when the sample is placed in a low humidity environment until the sample temperature reaches equilibrium and then transferred to a high humidity environment)}(° C.) / sample weight (g) [In formula A, the low humidity environment means an environment with a temperature of 20° C. and a relative humidity of 40%, and the high humidity environment means an environment with a temperature of 20° C. and a relative humidity of 90%.]

16. The artificial fur according to any one of claims 1 to 15, having a heat retention index calculated according to the following formula B of more than 0.

18. Formula B: Heat retention index = Heat retention rate (%) / sample basis weight (g / m ２ ) [In formula B, the heat retention rate (%) means the heat retention rate measured by the dry contact method (temperature 30°C, wind speed 30 cm / sec), and is calculated by (1-a / b) x 100. a indicates the amount of heat dissipated through the test piece, and b indicates the amount of heat dissipated without passing through the test piece.]

17. A step of obtaining a pile fabric having pile protruding from one or both sides of the fabric using fibers containing artificial protein fibers; and cutting the pile loops to form a cut pile. A method for producing artificial fur, wherein the artificial protein fibers contain modified fibroin fibers.

18. A step of obtaining a pile fabric having pile protruding from one or both sides of the fabric using the shrink-proof protein fiber; and cutting the pile loops to form a cut pile. A method for producing artificial fur, wherein the protein fibers contain modified fibroin fibers.

19. A step of obtaining a pile fabric having pile protruding from one or both sides of the fabric using fibers containing protein fibers; cutting the pile loops to form cut pile; and a step of shrink-proofing the pile fabric. A method for producing artificial fur, wherein the protein fibers contain modified fibroin fibers.

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