Method for preparing cocoons for reeling

Abstract

To provide a novel method for boiling cocoons without having to apply high-temperature heat treatment to a silk yarn, and which does not require a basic solution.SOLUTION: A method for preparing a silk reeling cocoon comprises: a contact stage for bringing the cocoon into contact with an organic solvent and / or an organic acid; and an infiltration stage for making water infiltrate into a cocoon layer and a cocoon cavity after the contact stage. Prior to the infiltration stage, the method further includes a removal stage for removing the organic solvent and / or organic acid. The infiltration stage is performed using an immersion method. The infiltration stage includes a cocoon cavity depressurization step to reduce pressure within the cocoon cavity. The infiltration stage is performed using a method selected from low-temperature depressurization, boiled cocoon cooling, and contact steaming.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for preparing cocoons for reeling, the cocoons for reeling prepared thereby, and a method for producing raw silk. [Background technology]

[0002] The use of biological materials has attracted more attention as genetic manipulation and genomic information have become easier to use, and is currently expanding. Research and development into this field is not only being actively pursued in the development of pharmaceuticals using cells, but also in the field of materials.

[0003] Silk thread, a biological material, is an ideal base for developing new materials from the viewpoints of its strength, texture, manufacturing method, processing method, etc. In fact, many studies have been conducted to impart new functions to silk thread (Patent Document 1 and Non-Patent Document 1).

[0004] Conventional silk production methods involve several heating steps, such as drying, boiling cocoons, and degumming. In recent years, attempts have been made to add various proteins to silk threads using genetic engineering techniques in order to impart new functions to silk threads. However, the heating steps can cause the added proteins to be thermally denatured, resulting in the loss of their functionality. There is an increasing need to develop new methods that do not inactivate the added proteins.

[0005] Cocoon boiling is a process in which cocoons are boiled to make it easier to pull out the thread end (cord). Conventionally, this process required boiling the cocoons in hot water. The present inventors have developed a method for treating cocoons at a low temperature of around 60°C using a basic solution, as a method that can be carried out at a relatively low temperature without denaturing proteins (Patent Document 2). This method has the problem that it is not suitable for proteins that are easily denatured in a basic environment, as it exposes the cocoons to a basic environment for a relatively long period of time. Therefore, there has been a demand for the development of a method that can be carried out at a lower temperature without inactivating the added functional protein. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-70293 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-95833 [Non-patent literature]

[0007] [Non-Patent Document 1] K. Kojima, et al., Biosci. Biotechnol. Biochem. 71, 2943 (2007) Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a novel method for boiling cocoons that does not require high-temperature heat treatment of silk threads and does not require a basic solution. [Means for solving the problem]

[0009] The inventors conducted extensive research to solve the above-mentioned problems. As a result, they found that by contacting cocoons with an organic solvent or organic acid, it is possible to prepare reelable cocoons at temperatures lower than those of previously developed methods, particularly at room temperature, without denaturing the proteins added to the silk thread. Furthermore, they found that when this method is applied to silk thread containing functional regions, the activity of the functional regions is maintained. They also found that treatment with an organic solvent or organic acid significantly promotes water penetration, so that similar effects can be obtained in a shorter time than conventional methods, even when using ordinary cocoons and boiling them at conventional temperatures. The present invention is based on these novel findings and provides the following:

[0010] (1) A method for preparing cocoons for reeling, comprising a contacting step of contacting the cocoons with an organic solvent and / or an organic acid, and a permeation step of permeating water into the cocoon shell and cocoon cavity after the contacting step. (2) The method according to (1), further comprising a removal step of removing the organic solvent and / or organic acid before the permeation step. (3) The preparation method according to (1) or (2), wherein the infiltration step is carried out by immersion. (4) A preparation method described in (1) or (2), wherein the infiltration step includes a step of reducing the pressure inside the cocoon cavity. (5) The preparation method according to (4), wherein the infiltration step is carried out by a method selected from the group consisting of a low-temperature decompression method, a cocoon boiling and cooling method, and a contact steaming method. (6) The preparation method according to any one of (1) to (5), wherein the organic solvent comprises one or more organic solvents selected from the group consisting of lower alcohols, acetone, N,N-dimethylformamide, acetonitrile, and ethyl acetate. (7) The preparation method according to any one of (1) to (6), wherein the organic acid includes acetic acid and / or propionic acid. (8) A cocoon for reeling prepared by the preparation method described in any one of (1) to (7). (9) A method for producing raw silk, comprising a cording step in which reeling cocoons obtained by the preparation method described in any one of (1) to (7) are corded, and a reeling step in which silk is reeled based on the thread spool obtained in the cording step. [Effects of the Invention]

[0011] According to the present invention, cocoons for reeling can be prepared at a temperature at which proteins do not denature. According to the present invention, cocoons for reeling can be prepared in a short time. Furthermore, according to the production method of the present invention, raw silk can be produced from the prepared cocoons for reeling. [Brief explanation of the drawings]

[0012] [Figure 1] This figure shows the amount of water absorbed by cocoons when treated with organic solvents using aqueous ethanol solutions of different concentrations, with error bars indicating standard deviation. [Figure 2] 1 shows the amount of water absorbed by cocoons when treated with different organic solvents, where the error bars indicate the standard deviation. [Figure 3] This is a diagram showing the appearance of cocoons containing the fluorescent protein Azami Green as a functional region when subjected to organic solvent treatment. In the figure, the upper row shows the appearance in bright field, and the lower row shows the appearance observed under fluorescent light. The order of the cocoons is the same in the upper and lower rows. The dashed line in the lower row indicates the position of the control cocoon. In the figure, "-" indicates that no Azami Green or ethanol treatment was performed, and "+" indicates that Azami Green or ethanol treatment was performed. [Figure 4] This is a diagram showing the appearance of cocoons containing the fluorescent protein Azami Green as a functional region when subjected to a normal cocoon boiling process. In the figure, the upper row shows the appearance in bright field, and the lower row shows the appearance under fluorescent observation. The order of the cocoon arrangement is the same in the upper and lower rows, with the left showing cocoons that were not boiled and the right showing cocoons that were boiled. The dashed line in the lower row indicates the position of the cocoons that were boiled. In the figure, "-" indicates that the cocoon did not undergo boiling, and "+" indicates that the cocoon did undergo either Azami Green or boiling treatment. [Figure 5] This is a diagram showing the appearance of cocoons containing the fluorescent protein Azami Green as a functional region when subjected to organic solvent treatment using acetic acid. In the figure, the upper row shows the appearance in bright field, and the lower row shows the appearance observed under fluorescent light. The order of the cocoons is the same in the upper and lower rows, with the left showing cocoons that were not treated with organic solvent and the right showing cocoons that were treated with organic solvent. The dashed line in the lower row indicates the position of the cocoons that were treated with organic solvent. In the figure, "-" indicates that no organic solvent treatment was included, and "+" indicates that either Azami Green or organic solvent treatment was included. DETAILED DESCRIPTION OF THE INVENTION

[0013] 1. Method of preparing cocoons for reeling 1-1. Overview A first aspect of the present invention is a method for preparing cocoons for reeling. The method of this aspect includes a contacting step and an infiltration step as essential steps. According to the method of this aspect, cocoons for reeling can be prepared at a lower temperature or in a shorter time.

[0014] 1-2.Definition "Reeling" refers to the process of producing raw silk by drawing out silk threads from the ends of corded cocoons. In this specification, "cocoon" refers to a structure consisting of a cocoon layer and an adult, pupa, exuvia, and / or larva. In this specification, cocoon includes cocoons produced by any silkworm, as long as the cocoon layer is composed of silk threads.

[0015] In this specification, the term "reeling cocoon" refers to a cocoon that has been processed so that the thread end can be easily pulled out using a cord. Typically, a reeling cocoon has a structure in which the cocoon cavity is filled with water and the cocoon itself cannot be pulled up during reeling.

[0016] As used herein, the term "cocoon cavity" refers to the space within a cocoon, i.e., the pupal chamber. For example, in the case of a silkworm cocoon, it refers to the space in which a silkworm larva, pupa, or adult is housed.

[0017] As used herein, the term "cocoon layer" refers to the wall of a cocoon made of silk threads. "Reeling" refers to the process of searching for and pulling out the thread ends from the cocoons. This is usually done with a reeling broom or the like, but in this specification, "reeling" includes any process of pulling out the thread ends from the reeling cocoons, regardless of the means.

[0018] As used herein, the term "thread end" refers to the end of a silk thread that has been released from a cocoon. As used herein, "silk thread" refers to a thread derived from silkworms, and refers to a protein thread produced by larvae or adults of silkworms for the purposes of nesting, moving, anchoring, spinning cocoons, capturing food, etc. Silk threads as used herein include those derived from any silkworm.

[0019] As used herein, the term "silkworm" refers to a general term for insects that have silk glands and can spin silk threads, and generally refers to species that can spin silk threads during their larval stage for nest-building, cocoon-spinning, or movement.

[0020] As used herein, "raw silk" refers to silk threads that have been reeled from cocoons and still contain adhesive substances such as sericin. Raw silk as used herein includes not only reeled silk, but also doubled and / or twisted silk.

[0021] In this specification, the term "organic solvent" refers to an organic compound that is in a liquid state at room temperature and normal pressure.

[0022] As used herein, the term "lower alcohol" refers to an organic compound having four or less carbon atoms and a hydroxyl group, and a derivative thereof. In this specification, the term "lower alcohol" includes both straight-chain lower alcohols with an unbranched carbon chain and branched-chain lower alcohols with a branched carbon chain.

[0023] As used herein, the term "organic acid" refers to an organic compound that can donate a proton to another compound. The organic acid as used herein primarily refers to an acidic organic solvent that is liquid at room temperature and normal pressure.

[0024] "Contact" means that one substance comes into direct physical contact with another substance. "Permeation" refers to the movement of a liquid present outside a substance or space through the surface of the substance or the structure surrounding the space to the inside. For example, "permeating the cocoon layer" refers to the liquid outside the cocoon soaking into the cocoon layer, and "permeating into the cocoon cavity" refers to the liquid outside the cocoon passing through the cocoon layer and moving into the cocoon cavity.

[0025] "Removal" refers to the process of removing at least a portion of a specific substance contained in a structure from the structure. In this specification, removal includes both active removal of the specific substance and passive removal by placing the specific substance in a situation where it can be lost.

[0026] As used herein, "immersion" refers to immersing a part or all of a target substance in a liquid. As used herein, "reducing pressure" refers to reducing atmospheric pressure or vapor pressure. As used herein, reducing pressure includes both a direct reduction in atmospheric pressure or vapor pressure and an indirect reduction thereof by, for example, a temperature change.

[0027] 1-3.Configuration The method of this embodiment includes a contacting step and a permeating step as essential steps, and includes a drying step, a removing step, and a washing step as optional steps.

[0028] 1-3-1. Drying process The "drying step" is an optional step in which the cocoons and / or pupae within the cocoon cavity are dried to prepare dried cocoons.

[0029] This step is usually carried out for the purpose of killing pupae and / or preserving them for a long period of time within the cocoon cavity. Therefore, whether or not this step is necessary can be determined taking into consideration the conditions such as the cocoons to be used and the necessity of preservation. For example, this step does not need to be carried out when using cocoons that do not contain pupae within the cocoon cavity or when they are not to be preserved.

[0030] The drying method used in this step is not particularly limited, and may be, for example, a method used for drying raw silkworm cocoons. Specific examples include air drying such as hot air drying, natural drying such as sun drying, drying by infrared rays, reduced-pressure drying in which evaporation is performed by degassing in a container using a vacuum pump or the like, freeze drying in which water is evaporated while the material is frozen, air drying using warm or cold air, dehumidification drying using a dehumidifier or the like, drying by electromagnetic waves, or a combination thereof. Any of these methods can be performed manually or automatically using a machine or the like.

[0031] The cocoons may be subjected to additional treatment during drying. For example, when natural drying is performed, the cocoons may be frozen or refrigerated before or after the drying.

[0032] 1-3-2. Contact process The "contact step" is an essential step in which the cocoons are brought into contact with an organic solvent and / or an organic acid (hereinafter, in this specification, often collectively referred to as "organic solvent, etc."). When a drying step is performed, this step can be performed after that.

[0033] <Cocoon> The cocoons used in this step are not particularly limited. For example, the insect from which they are derived, their composition and type can be selected arbitrarily depending on the purpose.

[0034] The silkworms from which the cocoons are derived are not particularly limited, but are preferably species belonging to the order Lepidoptera that can spin large amounts of silk. For example, species belonging to the families Bombycidae, Saturniidae, Brahmaeidae, Eupterotidae, Lasiocampidae, Psychidae, Archtiidae, and Noctuidae are preferred silkworms in this specification. Particularly preferred are species belonging to the genera Bombyx, Samia, Antheraea, Saturnia, Attacus, and Rhodinia, specifically Bombyx mori (domestic silkworm; hereinafter, both larvae and adults of silkworms are collectively referred to as "silkworms"), Bombyx mandarina, Samia cynthia (including Samia cynthia ricini and hybrids of Samia cynthia and Samia ricini), Antheraea yamamai, Antheraea pernyi (tussah silkworm), Saturnia japonica, and Actia gnoma. Genetically modified versions of these and mutants obtained by genome editing or the like can also be used. The cocoons used in the present method may be derived from a single individual, from multiple individuals, or may be a mixture of cocoons derived from multiple species.

[0035] When using cocoons derived from genetically modified organisms, the cocoons may be made of genetically modified silk thread.

[0036] As used herein, "genetically modified silk" refers to silk that has undergone genetic manipulation of the genes for silk components. Genetically modified silk not only includes silk that has been genetically modified to contain sericin or fibroin, which constitute the silk, but also silk that has had its properties altered by genetic modification, such as silk that has had its internal structure altered by genetic modification. Genetically modified silk can include, for example, a functional region.

[0037] As used herein, the term "functional region" refers to a protein region that has been introduced into a silk thread by genetic recombination to impart a desired function. Furthermore, in this specification, silk thread into which a functional region has been introduced is referred to as "functional silk thread" or the like. "Functional" means that the functional region exhibits activity.

[0038] The type of functional region is not particularly limited and includes any protein or part thereof, for example, enzymes, antibodies, binding proteins such as receptors and ligands, neuropeptides, hormones, fluorescent proteins, luminescent proteins, and parts thereof.

[0039] For example, fluorescent proteins include GFP, DsRed, TurboRFP and variants thereof, as well as various fluorescent proteins of different origins such as Azami Green.

[0040] The number and types of functional regions are not particularly limited. The silk thread used in the present invention can contain, for example, one or more functional regions of the same type, or multiple functional regions of different types. When multiple functional regions are contained in a single molecule, their arrangement is also not particularly limited. For example, one or more types of functional regions can be introduced linked to each other at the same location, or dispersed at different locations.

[0041] The functional region to be used can be appropriately selected depending on its properties, etc. For example, among fluorescent proteins, Azami Green has a higher quantum yield than GFP and produces stronger fluorescence from the same intensity of excitation light, but Azami Green, particularly in the monomer form, has properties such as being inferior to GFP in terms of pH stability (Karasawa et al., J. Biol. Chem. 278(36): 34167-71 (2003)).

[0042] The functional domain used in the methods of the present invention may be a protein or portion thereof that is susceptible to thermal denaturation and / or denaturation in basic conditions.

[0043] The origin of the functional region is not particularly limited. For example, it may be derived from an endogenous gene or an exogenous gene of the silkworm.

[0044] As used herein, the term "exogenous gene" refers to any gene introduced from outside. As used herein, the term "exogenous gene" includes both natural genes and artificial genes. In the case of an exogenous gene, the organism from which it originates is not particularly limited. The type of exogenous gene is not particularly limited. For example, it may be a gene not derived from silk thread, a gene derived from silk thread, or a combination thereof.

[0045] The method for introducing the gene is not particularly limited, and the gene can be introduced using gene recombination techniques known in the art.

[0046] There are no particular limitations on the treatment that is applied to the cocoons used in this step. Specifically, for example, cocoons produced by silkworms can be used as they are, or can be optionally treated prior to this step. Specifically, for example, both live cocoons and dried cocoons obtained by drying live cocoons can be used.

[0047] There are no particular limitations on the treatment that can be applied to the silk thread before this method, but if the aim is to avoid high-temperature heat treatment, it is preferable that this step does not include treatment at high temperatures (e.g., 80°C or higher).

[0048] <Organic solvents, etc.> The temperature of the organic solvent is not particularly limited. For example, it can be a temperature above the melting point or below the boiling point of the organic solvent used. Specifically, for example, the temperature is -120°C or higher, -100°C or higher, -90°C or higher, -80°C or higher, -50°C or higher, -30°C or higher, -20°C or higher, -10°C or higher, -5°C or higher, -2°C or higher, -1°C or higher, 0°C or higher, 3°C or higher, 5°C or higher, 10°C or higher, 12°C or higher, 15°C or higher, 17°C or higher, 18°C ​​or higher, 19°C or higher, 20°C or higher, 23°C or higher, 24°C or higher, or 25°C or higher. Specific upper limits of the temperature are, for example, 100°C or less, 90°C or less, 80°C or less, 79°C or less, 75°C or less, 70°C or less, 65°C or less, 60°C or less, 55°C or less, 50°C or less, 45°C or less, 40°C or less, 37°C or less, 35°C or less, 33°C or less, 31°C or less, or 30°C or less. The temperature does not need to be kept constant throughout this step as long as it is generally within the above temperature range. If necessary, the temperature can be adjusted using freezing means, refrigeration means, warming means, heating means, and / or heating means known in the art.

[0049] The type of organic solvent is not particularly limited, and either a water-soluble or a water-insoluble organic solvent can be used.

[0050] As used herein, "water-soluble" refers to the property of having a solubility in water at one atmosphere and 20°C that is greater than a certain level. The solubility of a water-soluble organic solvent is not particularly limited, but is, for example, greater than 8,000 mg / L. Specifically, for example, the solubility is 8,500 mg / L or more, 9,000 mg / L or more, 9,500 mg / L or more, 10,000 mg / L or more, 15,000 mg / L or more, 20,000 mg / L or more, 25,000 mg / L or more, 30,000 mg / L or more, 50,000 mg / L or more, 100,000 mg / L or more, 250,000 mg / L or more, 500,000 mg / L or more, or 1,000,000 mg / L. "Water-insoluble" refers to the property of not being water-soluble.

[0051] Examples of the water-soluble organic solvent include, but are not limited to, lower alcohols, acetone, N,N-dimethylformamide, acetonitrile, carboxylic acid derivatives such as ethyl acetate and formamide, polyhydric alcohols such as ethylene glycol and glycerin, other alcohols such as diethylene glycol, alcohol derivatives such as alcohol ethers and alcohol ether esters, sulfoxides such as dimethyl sulfoxide, polyethers, and lactones.

[0052] Non-water-soluble organic solvents include, but are not limited to, chloroform, isoamyl alcohol (also called isopentyl alcohol), and aromatic compounds such as xylene, benzene, hexane, and toluene.

[0053] Furthermore, for example, a low surface tension solvent may be used as the organic solvent. A low surface tension solvent refers to an organic solvent having a surface tension lower than that of pure water. Since the surface tension of pure water is 72.75 mN / m at 20°C, the surface tension of the low surface tension solvent may be less than 72.75 mN / m (20°C). Specifically, for example, solvents having a surface tension at 20°C of less than 72.75 mN / m, less than 70 mN / m, less than 65 mN / m, less than 60 mN / m, less than 55 mN / m, less than 50 mN / m, less than 45 mN / m, less than 40 mN / m, or less than 38 mN / m may be used.

[0054] Examples of organic acids include carboxylic acids including aliphatic carboxylic acids such as formic acid, acetic acid, and propionic acid, and aromatic carboxylic acids such as benzoic acid and salicylic acid, sulfonic acids such as methanesulfonic acid, and acidic alcohols such as phenols and enols.

[0055] The organic solvent does not have to be a pure substance. For example, a mixture of an inorganic compound such as water and / or other organic solvents can be used. In this case, the concentration of the organic solvent is not particularly limited. For example, the concentration may be 20% by volume or more, 30% by volume or more, 40% by volume or more, 45% by volume or more, 50% by volume or more, 55% by volume or more, 59% by volume or more, 60% by volume or more, 61% by volume or more, 64% by volume or more, 65% by volume or more, 66% by volume or more, 69% by volume or more, 70% by volume or more, 71% by volume or more, 74% by volume or more, 75% by volume or more, 76% by volume or more, 79% by volume or more, 80% by volume or more, 81% by volume or more, 90% by volume or more, or 99.5% by volume or more, based on the total volume of the mixture. The concentration need only be approximately within the above range during this process and does not need to be maintained constant. Furthermore, for example, the organic solvent or other components may be added or the solution may be replaced during this process.

[0056] In this step, it is sufficient that at least a portion of the organic solvent, etc., is liquid. It is not necessary for the entire organic solvent, etc., to be maintained in liquid form during this step. For example, a portion of the organic solvent, etc., may be vaporized or solidified during this step. For example, if the pure substance is in a form other than liquid but can become liquid by mixing with another substance, it may be preferable to use it as a mixture.

[0057] The organic solvent used in the present invention may contain any other component as needed, such as a buffer, a pH adjuster, a surfactant, or a chelating agent.

[0058] There are no particular limitations on the amount of liquid such as organic solvent. For example, when contact is carried out by immersion, the bath ratio, which indicates the total volume of the liquid when the weight of the cocoon shell is taken as 1, is usually 1:0.5 or more, 1:1 or more, 1:1.5 or more, 1:2 or more, 1:5 or more, or 1:10 or more.

[0059] The conditions for the organic solvent, such as temperature, can be selected appropriately depending on the purpose and the properties of the silk fibers that make up the cocoons. For example, the temperature of the organic solvent may be determined based on the physical properties, such as the boiling point and melting point, of the organic solvent used. Conditions may also be selected depending on the purpose. For example, if the purpose is to avoid heat treatment, organic solvents at temperatures below 80°C, below 60°C, room temperature (15°C to less than 40°C), or below room temperature can be used, and if the purpose is to shorten the time, organic solvents at higher temperatures can be used.

[0060] The organic solvent and the like used in this step may be prepared before this step or simultaneously with this step. Specifically, for example, components may be added and / or renewed during this step.

[0061] <Contact> There are no particular limitations on the method as long as the solid (cocoons) and the liquid (organic solvent, etc.) can be directly contacted with each other. In this step, since both components are brought into contact, a method suitable for contacting a solid with a liquid is preferred. Specifically, for example, the cocoons can be contacted by immersing them in an organic solvent, spraying, spraying, or applying the organic solvent to the cocoons, or a combination thereof.

[0062] For example, known methods used in boiling or scouring silkworm cocoons can be used for contacting. Specific methods include manual methods, such as hanging the cocoons directly from something or placing them in a bag or the like and immersing them in liquid, or methods using a machine to spray the liquid. The hanging method, the bag-containing method, and the spraying method can be carried out in accordance with methods used in scouring, such as the hanging method, the bag-based method, and the spraying method. The "hanging method" is a method in which fabric or silk thread is suspended from a rod or pole placed above or inside a pot and immersed in liquid in a pot, and is classified into the rod-based method, the bar-based method, etc., depending on the method used. The "bag-based method" is a method in which cocoons or silk thread are placed in a bag such as a cotton bag and immersed in liquid. The "spraying method" is a method in which liquid is sprayed onto silk thread using a machine.

[0063] When a method using immersion is used, it is not necessary for the entire cocoon to be under the liquid surface at once, and it is sufficient that the entire cocoon is brought into contact with the organic solvent, etc. as a result of, for example, changing the position, mixing, rotating, etc. Even when a method other than immersion is used, it is preferable to perform an operation such that the entire cocoon can be brought into contact with the organic solvent, etc., by changing the position or rotating the cocoon, etc.

[0064] The contact time is not particularly limited as long as the organic solvent or the like can penetrate into the cocoon shell. For example, it can be determined in relation to the temperature and properties of the organic solvent or the like. Generally, the lower the temperature, the longer the time, and the higher the temperature, the shorter the time. Specifically, the contact time is, for example, 1 second or more, 3 seconds or more, 5 seconds or more, 6 seconds or more, 9 seconds or more, 10 seconds or more, 11 seconds or more, 15 seconds or more, 20 seconds or more, 25 seconds or more, or 30 seconds or more. Note that in this process, the organic solvent or the like can penetrate into the cocoon cavity.

[0065] The contact can be carried out multiple times. In this case, the composition of the organic solvent, etc., the contact time, the temperature, etc. may be changed for each contact, or the same solvent as used in the previous contact may be used as is.

[0066] 1-3-3.Removal process The "removal step" is an optional step of removing the organic solvent and / or organic acid from the cocoon shell. This step can be performed after the contact step.

[0067] Whether or not this step is necessary can be determined taking into consideration conditions such as the type and concentration of the organic solvent, etc. used in the contacting step. This step is usually carried out when a water-insoluble organic solvent, etc. is used in the contacting step. Even when an organic solvent, etc. containing a water-insoluble organic solvent, etc. is used in the contacting step, this step may not be carried out, for example, depending on the type of the organic solvent, or if the organic solvent, etc. contains a water-soluble organic solvent, etc. or a surfactant.

[0068] The removal method used in this step is not particularly limited, and can be, for example, drying, dropping, centrifugation, suction, air blowing, or a combination thereof.

[0069] When drying is performed, the method is not particularly limited, but for example, the above-mentioned method for the drying step such as under reduced pressure can be used.

[0070] The method of dropping is not particularly limited as long as it allows the organic solvent to fall off by gravity. For example, the cocoons can be left to stand to allow the organic solvent to fall off. In this case, the cocoons may be given a stimulus such as rotation or vibration.

[0071] When centrifuging, the method is not particularly limited as long as it is a method that can remove the organic solvent etc. by utilizing centrifugal force. For example, it can be performed manually or automatically using a centrifuge etc.

[0072] When aspirating, the method is not particularly limited, and can be performed, for example, manually by breathing or using a syringe, or by using an aspirator or the like.

[0073] When blowing air, the method is not particularly limited as long as it is a method that can use wind pressure to remove the organic solvent, etc. For example, it can be done manually by breathing or using a fan, or by using a blower, etc.

[0074] This step can be carried out multiple times, and in that case, the method and conditions used may be the same each time or may be different each time.

[0075] 1-3-4. Cleaning process The "washing step" is an optional step in which the silk threads are brought into contact with water, an aqueous solution, or other organic solvents to wash the cocoons. This step can be carried out after the contacting step. Furthermore, if a removing step is carried out, this step can be carried out simultaneously with or after the removing step. In particular, if the method includes multiple steps, this step can be carried out between each of the steps. For example, if a drying step is carried out, this step can be carried out between the drying step and the contacting step and / or after the contacting step. If the contacting step is carried out multiple times, this step can be carried out between each contact.

[0076] The washing liquid used in this step is not particularly limited, but examples thereof include surfactants, water-soluble or volatile organic solvents such as toluene, benzene, and ethanol, and water.

[0077] This step can be carried out multiple times, in which case the composition and temperature of the liquid used may be the same each time or may be different each time.

[0078] 1-3-5. Penetration process The "permeation step" is an essential step in which water or an aqueous solution is permeated into the cocoon shell and cocoon cavity after contact. This step can be carried out simultaneously with or after the contact step, and also simultaneously with or after the removal step if one is carried out.

[0079] The composition of the aqueous solution used in this step is not particularly limited. For example, the aqueous solution may contain any other components as needed. Specific examples include alkaline agents such as sodium carbonate, sodium bicarbonate, and calcium carbonate; acid solutions such as citric acid, acetic acid, and propionic acid; metal ions; buffers; pH adjusters; surfactants; and chelating agents. Cocoon-cooking water used for boiling silkworm cocoons may also be used.

[0080] The temperature of the water and aqueous solution used in this step is not particularly limited. For example, water at the temperatures exemplified for the organic solvent, etc. (including cold water (less than 15°C), room temperature water (15°C or higher but less than 40°C), warm water (40°C or higher but less than 80°C), and hot water (80°C or higher)) can be used. The temperature of the hot water is not particularly limited, and is, for example, 80°C or higher, 85°C or higher, 90°C or higher, 93°C or higher, or 95°C or higher.

[0081] The method used in this step is not particularly limited. For example, a method used for normal boiling of silkworm cocoons can be used. For example, this step can be carried out by the immersion method. In this method, the cocoons are immersed in water for a certain period of time. The time is not particularly limited. For example, the immersion time can be 30 seconds or more, 1 minute or more, 1 minute 30 seconds or more, 2 minutes or more, 5 minutes or more, 6 minutes or more, 8 minutes or more, 10 minutes or more, 15 minutes or more, 20 minutes or more, 30 minutes or more, 40 minutes or more, 50 minutes or more, 60 minutes or more, or 90 minutes or more. Other conditions, etc., are the same as those described in detail for the immersion in the contact step.

[0082] This process may include a step of reducing the pressure inside the cocoon cavity. In this step, the pressure inside the cocoon cavity is reduced. The reduction in pressure in this step is carried out for the purpose of assisting water penetration into the cocoon cavity, so the method used and the degree of reduction in pressure are not particularly limited as long as this purpose is achieved.

[0083] Specific examples of the method include a reduced pressure method, a cooling method, and a catalytic steaming method. The decompression method is a method in which the air pressure in the space containing the cocoons is reduced while the cocoons are immersed in water or an aqueous solution. In this method, the pressure is usually reduced while the cocoons are immersed, and after maintaining the reduced pressure for a certain period of time, the pressure is restored to atmospheric pressure. In particular, the decompression method using cold water, room temperature water, or warm water is called the low-temperature decompression method, and the decompression method using hot water is called the high-temperature decompression method.

[0084] There are no particular limitations on the means for changing the air pressure. For example, methods include degassing and / or supplying air to the space (such as a container or a room) containing the cocoons, or changing the volume of the space (particularly the container). Commercially available pressure reducers may also be used.

[0085] The degree of pressure reduction is not particularly limited. Usually, it is low vacuum (10 5 Pa~10 2 For example, the gauge pressure, which indicates the strength of the pressure reduction, may be −50 mmHg or less, specifically −750 mmHg to −50 mmHg, −700 mmHg to −100 mmHg, −650 mmHg to −200 mmHg, or −600 mmHg to −300 mmHg.

[0086] The time for which the reduced pressure state is maintained is not particularly limited, and can be maintained for the time exemplified in the immersion method, for example.

[0087] After maintaining the reduced pressure, the pressure is restored to normal atmospheric pressure (for example, 1 atmosphere). At this time, the pressure is preferably restored slowly, but is not limited to this. Specifically, the pressure is restored over, for example, 1 second or more, 2 seconds or more, 5 seconds or more, 10 seconds or more, 30 seconds or more, 40 seconds or more, 1 minute or more, or 2 minutes or more.

[0088] The cooling method involves varying the temperature of the water used for steeping, with a first steeping in relatively high temperature water followed by a second steeping in relatively low temperature water.

[0089] The temperature difference between the first and second soaking is not particularly limited, and can be, for example, 10°C or more, 15°C or more, 20°C or more, 25°C or more, 30°C or more, or 35°C or more. The temperature of each soaking is not particularly limited, and can be appropriately selected, for example, from the water temperatures exemplified in this process. In this specification, a method using hot water for the first soaking is called the cocoon-cooking cooling method, and a method using water at a temperature lower than warm water for the first soaking is called the low-temperature cooling method. For example, the cocoon-cooking cooling method can use hot water for the first soaking and warm water for the second soaking. The temperature of the hot water used in the cocoon-cooking cooling method can be, for example, 90°C or more or 95°C or more.

[0090] The duration of the first and second immersions is not particularly limited. For example, the immersion can be performed for the time exemplified in the immersion method, but the method of the present invention can achieve the same effect in a shorter time than usual. Therefore, each immersion can be performed for, for example, 5 minutes or less, 3 minutes or less, 2 minutes or less, or 1 minute 30 seconds or less. The duration of the first and second immersions may be the same or different. For example, the first immersion can be performed longer than the second immersion.

[0091] The steaming method is a method in which high-temperature steam is applied to the cocoons instead of the first immersion in the cooling method. The temperature of the steam may be, for example, the same as the temperature of the hot water used in the cooling method.

[0092] Other conditions such as temperature difference are the same as for the cooling method. This step may be carried out using a known machine such as a cocoon cooker.

[0093] The method and conditions to be used can be selected appropriately taking into consideration the purpose, the properties of the silk threads that make up the cocoons, the facilities, etc. For example, if the purpose is to avoid heat treatment, the low-temperature reduced pressure method or low-temperature cooling method can be used, and if the purpose is to shorten the cocoon boiling time, the high-temperature reduced pressure method, cocoon boiling and cooling method, or contact steaming method can be used.

[0094] This step can be carried out multiple times, and in that case, the same method and conditions may be used, or the method and conditions may be changed each time.

[0095] The methods and conditions used in the methods of the present invention may be determined, for example, in relation to the stringing efficiency (the proportion of cocoons that can be stringed), the reeling rate (the number of cocoons per cut), or the amount of water absorption. For example, the stringing efficiency may be determined to be 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 85% or more, 90% or more, 95% or more, or 100%. Alternatively, the methods and conditions may be determined, for example, so that the reeling rate is 80% or more.

[0096] The amount of water absorbed per cocoon varies depending on the cocoon used, but typically should be 1 g or more, 1.1 g or more, 1.2 g or more, 1.3 g or more, or 1.4 g or more, or, for example, 1.05 times or more, 1.06 times or more, 1.075 times or more, 1.1 times or more, 1.15 times or more, 1.2 times or more, 1.3 times or more, 1.4 times or more, 1.5 times or more, or 1.6 times or more compared to when the same infiltration process is carried out using cocoons that have not been treated with an organic solvent or the like.

[0097] 1-4.Effects The method of this embodiment makes it possible to prepare cocoons for reeling at low temperatures or in a short time. These cocoons for reeling can be untied and reeled as they are. Furthermore, it is possible to obtain cocoons for reeling that retain the activity of functional regions that are susceptible to thermal denaturation and / or denaturation under basic conditions. Furthermore, the method of this embodiment makes it possible to cook cocoons in a shorter time using standard cocoon cooking equipment. Therefore, the method of the present invention can be used for various purposes, such as reducing the load on silk threads, shortening the processing time, or reducing silk reeling costs.

[0098] Although the method of this embodiment can produce cords and cocoons ready for reeling, it is also possible to store or provide cocoons prepared without carrying out the infiltration step of this method as cocoons for infiltration before reeling. In this case, the stored or provided cocoons for infiltration before reeling can be subjected to the infiltration step to prepare cocoons for reeling, which can then be used for reeling.

[0099] 2. Raw silk manufacturing method 2-1. Overview The second aspect of the present invention is a method for producing raw silk. The method of this aspect includes a cording step and a reeling step as essential steps. According to the method of this aspect, raw silk can be produced from the reeling cocoons prepared in the first aspect.

[0100] 2-2.Configuration The method of this embodiment includes a cording step and a reeling step as essential steps.

[0101] 2-2-1. Cording process The "stringing step" is an essential step in which stringing is performed on the reeling cocoons obtained in the first embodiment.

[0102] The reeling cocoon has been described in detail in the first embodiment, so a detailed description thereof will be omitted here. The method and conditions used in this step are not particularly limited. For example, methods commonly used for reeling silkworm cocoons can be used. For example, the reeling can be carried out by rubbing the surface of the cocoons with a broom or the like in the water in which the cocoons are soaked during reeling (hereinafter often referred to as "reeling water" in this specification). As long as a large amount of water is not lost from the cocoon cavity, it is not necessary to carry out this step while the cocoons are immersed in water. Furthermore, there are no particular limitations on the method for rubbing the cocoon surface, as long as it allows the thread end to be pulled out.

[0103] The temperature and composition of the reeling water are not particularly limited, but for example, the reeling water used in normal reeling of silkworm cocoons may be used, or one exemplified in the section on impregnation in embodiment 1 may be used. For example, when this method is carried out consecutively with the method described in embodiment 1, the water used for impregnation may be used as the reeling water as is, or the water used in this step may be replaced after this step or its composition may be changed before being used in the reeling step.

[0104] 2-2-2. Reeling process The "spinning process" is an essential process in which spinning is carried out using the thread end obtained in the cording process. This process can be carried out simultaneously with or after the cording process.

[0105] Any of the thread ends drawn out in the cording process can be selected for reeling. For example, similar to the cording process used in the normal silkworm cocoon reeling method, the process of drawing out further thread ends can be continued until only one thread end remains.

[0106] The method used in this step is not particularly limited. For example, a method commonly used for reeling silkworm cocoons can be used. Furthermore, since the main purpose of this step is to produce raw silk from cocoons, any method that can reel silk from cocoons can be used in this step.

[0107] This process may be carried out manually by hand reeling or counter-reeling, or may be carried out by controlling the fineness using a counter-reeler or multi-row reeling machine to reel in a fixed size, or an automatic reeling machine to reel in a fixed fineness.

[0108] If necessary, it is possible to address defects in the yarn such as cording, or to control the fineness of the yarn by doubling and / or twisting, etc. These methods are known in the art and are not particularly limited.

[0109] The method may be carried out as a series of steps using an automatic reeling machine which allows for continuous cording and reeling.

[0110] 2-3. Uses of raw silk Any desired products can be manufactured from the raw silk obtained by the method of this embodiment and / or the degummed silk obtained by degumming the raw silk, such as nonwoven fabrics, fillers, surgical sutures, woven fabrics, knitted fabrics, and musical instrument strings.

[0111] In this case, any other fiber material may be included, and although not particularly limited, specific examples include natural fibers including other animal fibers such as wool and plant fibers such as cotton, semi-synthetic fibers such as acetate, regenerated fibers such as rayon, synthetic fibers such as polyester, and inorganic fibers such as glass fibers.

[0112] The use of the product is not particularly limited. For example, when the reeling cocoons used in the method of this embodiment are prepared at low temperatures, even if the silk contains a functional region that is susceptible to thermal denaturation, raw silk that retains its activity can be obtained by the method of this embodiment. In such cases, the product may be used in an application in which the functional region can exert its function.

[0113] By carrying out the method of the first embodiment at a low temperature and then scouring the silk thread using a scouring method that can be carried out at a low temperature after the method of the present embodiment, it is possible to obtain a degummed silk thread containing a functional region that is capable of functioning, even if the silk thread contains a functional region that is susceptible to thermal denaturation. Any known method can be used as the scouring method in this case. [Example]

[0114] Example 1: Improvement of ripping efficiency by organic solvent treatment (the purpose) The effect of treatment with organic solvents on the efficiency of cocoon stringing is investigated.

[0115] (method) As samples, dried cocoons of Gunma 200 silkworm moths were used. The organic solvent treatment was carried out by immersing the cocoons in the organic solvent of the following composition for 30 seconds.

[0116] As the organic solvent, aqueous ethanol solutions with ethanol concentrations of 20, 40, 60, 80 and 99.5% by volume were used. As a control, water containing no ethanol (0% by volume aqueous ethanol solution) was used.

[0117] After the organic solvent treatment, the cocoon was immersed in water at room temperature and left to stand for 8 minutes under reduced pressure (gauge pressure: -600 mmHg) to allow water to penetrate into the cocoon cavity. After the pressure was restored to atmospheric pressure over two minutes, the surface of the cocoon was rubbed with a cord broom to pull out the thread.

[0118] The threading efficiency was calculated as the percentage of cocoons from which the correct thread was pulled out out of the cocoons (10 each) used under each condition.

[0119] (result) The results are shown in Table 1.

[0120] [Table 1]

[0121] Table 1 shows the ligation efficiency when each organic solvent was used. The ligation efficiency increased depending on the ethanol concentration. While the 0% ethanol control showed a ligation efficiency of 20%, the 40% ethanol aqueous solution showed an excellent ligation efficiency of 60%, 60% ethanol aqueous solution, 80% ethanol aqueous solution, 80% ethanol aqueous solution, and 99.5% ethanol aqueous solution showed an excellent ligation efficiency of 100%.

[0122] Observation of the cocoons revealed that in the control cocoon, there were patches of water-permeated (translucent) and non-permeated (white) areas. On the other hand, in the organic solvent-treated cocoons, the cocoon layer was translucent throughout, indicating that water had been uniformly permeated.

[0123] Furthermore, when reeling was performed from the thread spool pulled out by the cord, it was possible to reel more than 450 meters of silk thread from each of the corded cocoons. According to the selection criteria for water-reeling strains (Dai Nippon Sanshikai Silk News No. 41 p. 2-3 (2011)), all of the cocoons were deemed capable of being reeled.

[0124] Furthermore, we compared the physical properties of raw silk reeled from raw cocoons of Ariake, a four-way hybrid of Japan and China, using the same process as above with that of raw silk reeled from dried cocoons of the same variety that had been boiled in the usual way. As a result, no significant differences in physical properties were observed between the two, with the former having a strength of 4.25±0.10g / d and the latter having a strength of 4.29±0.05g / d.

[0125] From the above, it was found that organic solvent treatment makes it possible to prepare cocoons that can be corded and reeled without heating, without affecting the physical properties of the raw silk.

[0126] Example 2: Relationship between water penetration into cocoon shell and organic solvent concentration (the purpose) We investigate the effect of organic solvent treatment on water penetration into the cocoon layer and the relationship between organic solvent concentration and penetration.

[0127] (method) The sample and organic solvent treatment were basically the same as in Example 1. The amount of water absorbed was calculated for each cocoon by subtracting the weight of the cocoon before treatment with the organic solvent from the weight of the cocoon after the water in the cocoon cavity had been removed after the pressure was restored. Here, the water in the cocoon cavity was removed by lifting the cocoon out of the water after the pressure was restored and then reducing the pressure again. Experiments were conducted using 10 cocoons for each concentration condition.

[0128] (result) The results are shown in Figure 1. Figure 1 is a graph showing the amount of water absorbed by cocoons (cocoon shells) after organic solvent treatment using aqueous ethanol solutions of different concentrations. The amount of water absorbed by the cocoon shells varied depending on the ethanol concentration, with a significant increase when 60% ethanol was used compared to the 0% ethanol control. Furthermore, the amount of water absorbed increased further at concentrations of 80% or higher, with no significant difference observed between 80% and 99.5% ethanol.

[0129] From the above, it was found that the water absorption of the cocoon shell increases with organic solvent treatment, and that this increase is concentration-dependent.

[0130] Example 3: Relationship between water penetration into cocoon shell and type of organic solvent, etc. (the purpose) The amount of water absorbed by the cocoon layer is measured by changing the type of organic solvent used, and the relationship between the type of organic solvent and penetration is investigated.

[0131] (method) The sample and organic solvent treatment were basically the same as in Example 2. As the organic solvent, 99.5 to 99.8% by volume of aqueous ethanol solution, aqueous methanol solution, and aqueous 2-propanol solution were used. Experiments were conducted using 10 cocoons for each condition.

[0132] (result) The results are shown in Figure 2. Figure 2 is a graph showing the amount of water absorbed by the cocoon shell when treated with different organic solvents. Regardless of the organic solvent used, good water absorption of 1.4 g or more per cocoon was observed. Furthermore, there was no significant difference in the amount of water absorbed depending on the type of solvent.

[0133] In addition, for organic solvents (ethyl acetate, acetone, N,N-dimethylformamide, and acetonitrile) and organic acids (acetic acid and propionic acid), a simple penetration test into the cocoon shell was conducted using cocoon fragments, and good penetration into the cocoon shell and replacement with water were confirmed.

[0134] When chloroform and isopentyl alcohol were used as organic solvents, good penetration of the organic solvents into the cocoon layer was observed, but replacement with water was difficult, and they had to be removed by washing with a water-soluble organic solvent (ethanol, etc.).

[0135] This indicates that any organic solvent can promote the penetration of water into the cocoon shell, regardless of its type.

[0136] Example 4: Effect of exposure to organic solvents on functional regions in silk threads (the purpose) The cocoons containing the functional regions are exposed to organic solvents to examine the effect of organic solvents on the functional regions.

[0137] (method) The samples used were dried cocoons obtained from silkworms that spin silk containing green fluorescent protein as a functional region in the fibroin H chain. As a control, dried cocoons of a normal variety (variety: Nihon 137 x Shi 146) that does not contain the functional region were used.

[0138] Silkworms expressing fibroin fused with GFP or Azami Green (background strains: GFP: Gunma × 200; Azami Green: Nihon No. 604 × Chu No. 511) were used as green fluorescent proteins.

[0139] An 80% by volume aqueous solution of ethanol was used as the organic solvent. The cocoons were exposed to the organic solvent by immersing them in an 80% ethanol solution for 30 seconds, then leaving them to dry naturally for a day. This allowed the cocoons to be exposed to the ethanol until the ethanol completely evaporated from the cocoon shell and cocoon cavity.

[0140] In addition, some cocoons containing Azami Green as a functional region were boiled in the usual way without organic solvent treatment, using a VP-type vacuum boiler (Harada Co., Ltd.).

[0141] Control cocoons, cocoons that had not been exposed to the above treatment, and treated cocoons were observed under bright field. We also observed the fluorescence of the cocoons in the dark using a blue LED as excitation light.

[0142] (result) The results are shown in Figures 3 and 4. Figure 3 shows the appearance of cocoons containing Azami Green as a functional region when they were subjected to organic solvent treatment. The intensity of the fluorescence observed did not change regardless of whether or not they were exposed to ethanol.

[0143] On the other hand, as shown in Figure 4, the fluorescence of Azami Green was lost when the normal cocoon boiling treatment was performed (Figure 4, right column) compared to when the cocoon boiling treatment was not performed (Figure 4, left column).

[0144] Similarly, no effect of organic solvents was observed when cocoons containing GFP as the functional region were used.

[0145] From the above, it was found that even when using cocoons containing functional regions whose activity may be lost by normal cocoon boiling, it is possible to prepare cocoons that can be reeled without losing their activity.

[0146] Example 5: Effect of organic acid treatment on functional regions and improvement of retrieval efficiency (the purpose) We investigate the effect of treatment with organic acids on the functional regions in silk threads and on the efficiency of stringing cocoons.

[0147] (method) The samples used were dried cocoons obtained from silkworms that spin silk containing thistle green as a functional region in the fibroin H chain, and dried cocoons from a normal variety (variety: Gunma 200) that does not contain the functional region.

[0148] As the organic acid, a 99.7% by volume aqueous solution of acetic acid was used. For the cocoons containing Azami Green, treatment was carried out in the same manner as in Example 4, except that a 99.7% by volume aqueous solution of acetic acid was used as the organic solvent, and the effect of acetic acid treatment on the cocoons was examined.

[0149] For normal variety cocoons (10 cocoons), the treatment was carried out in the same manner as in Example 1 except that a 99.7% by volume aqueous solution of acetic acid was used as the organic solvent, and the stringing efficiency was measured.

[0150] (result) The results are shown in Figure 5. Figure 5 shows the appearance of cocoons containing Azami Green as a functional region when they were subjected to organic acid treatment using acetic acid. The intensity of the fluorescence observed did not change regardless of whether or not the cocoons were exposed to acetic acid.

[0151] Furthermore, even when organic acid treatment using acetic acid was performed, an excellent retrieval efficiency of 80% was observed.

[0152] From the above, it was found that even when an organic acid such as acetic acid is used as the organic solvent, it is possible to prepare cocoons that can be reeled without impairing the activity of the functional region.

[0153] <Example 6. Shortening the cocoon boiling time using organic solvent treatment> (the purpose) When the cocoon boiling and cooling method is carried out after the organic solvent treatment, the effects of the organic solvent treatment on the cocoon boiling time, reeling efficiency, and physical properties of the reeled raw silk are investigated.

[0154] (method) Dried cocoons of size 137 (Japan) and 146 (China) were used as samples. The organic solvent treatment was carried out by immersing the cocoons in an 80% by volume aqueous solution of ethanol for 30 seconds.

[0155] The organic solvent-treated cocoons were immersed in hot water heated to 95°C for about 90 seconds, and then transferred to warm water at 60°C and immersed therein for about 60 seconds, thereby carrying out the cocoon boiling and cooling method.

[0156] As a control, cocoons were used that were not treated with organic solvents but were cooked in the usual way using a VP type vacuum cocoon cooker (Harada Co., Ltd.).

[0157] The cocoons boiled under each condition were corded using a cord broom and reeled into silk. The unwinding rate was calculated by a reeling test in accordance with the old cocoon testing method (Cocoon Testing Station Management Council, 1984). The physical properties of raw silk obtained by reeling were measured.

[0158] (result) The results are shown in Table 2.

[0159] [Table 2]

[0160] Table 2 shows the reeling efficiency and physical properties of the raw silk produced (reeled) from cocoons that were boiled using organic solvent treatment and those that were boiled normally. In the group that used organic solvent treatment, although the boiling time was significantly shorter (approximately 3 minutes compared to the usual approximately 15 minutes), there was no significant difference in the reeling efficiency, such as the reeling rate and cocoon filament length, compared to those that used normally boiled cocoons. Similarly, there was no difference between the boiling methods in the physical properties of the reeled raw silk, such as the strength and elongation.

[0161] This indicates that organic solvent treatment enables cocoons to be boiled in a significantly shorter time without impairing reeling efficiency or the physical properties of raw silk.

Claims

1. A method for preparing cocoons for reeling, comprising the steps of: A contacting step of contacting the cocoons with a liquid organic solvent and / or organic acid at a concentration of 30% by volume or more at a temperature of 65°C or less; After the contact step, a penetration step of penetrating water or an aqueous solution into the cocoon shell and cocoon cavity after the contact step. The preparation method comprising:

2. The preparation method according to claim 1 , further comprising a removal step of removing the organic solvent and / or organic acid before the permeation step.

3. The preparation method according to claim 1 or 2, wherein the infiltration step is carried out by immersion.

4. The preparation method according to claim 1 or 2, wherein the infiltration step includes a step of reducing the pressure inside the cocoon cavity.

5. 5. The method according to claim 4, wherein the infiltration step is carried out by a method selected from the group consisting of a low-temperature decompression method, a boiling and cooling method, and a contact steaming method.

6. 6. The method of any one of claims 1 to 5, wherein the infiltration step comprises a first immersion at a temperature of 90°C or higher and a second immersion at a temperature below 80°C, each for a time of 5 minutes or less.

7. The preparation method according to any one of claims 1 to 6, wherein the organic solvent comprises one or more organic solvents selected from the group consisting of lower alcohols, acetone, N,N-dimethylformamide, acetonitrile, and ethyl acetate.

8. The preparation method according to any one of claims 1 to 7, wherein the organic acid comprises acetic acid and / or propionic acid.

9. A cocoon for reeling prepared by the preparation method according to any one of claims 1 to 8.

10. A method for producing raw silk, comprising: A stringing step in which stringing is performed on the reeling cocoons obtained by the preparation method according to any one of claims 1 to 8; A reeling step in which reeling is performed based on the thread obtained in the cording step. The manufacturing method comprising:

Images