Method for manufacturing laminate

Abstract

[Problem] The present invention provides a method for manufacturing a laminate comprising a skin layer formed from a polymer compound containing a protein structure, the laminate having excellent surface properties. [Solution] This method for manufacturing a laminate comprises: a step for forming a skin layer precursor gel on a base fabric layer by inducing gelation of a skin layer-forming solution layer, which contains a polymer compound containing a protein structure and a solvent, in a member that comprises said base fabric layer and said skin layer-forming solution layer; a step for replacing the solvent in the skin layer precursor gel with a solvent replacement liquid by bringing the skin layer precursor gel into contact with the solvent replacement liquid; and a step for laminating and forming the skin layer on the base fabric layer by removing the solvent replacement liquid from the skin layer precursor gel and solidifying the skin layer precursor gel.

Description

Manufacturing method of laminate

[0001] The present invention relates to a method for producing a laminate.

[0002] Laminates in which a surface layer is laminated on a base fabric layer are used in various fields, such as synthetic leather and electronic materials. For example, synthetic leathers in which a surface layer is laminated on a base fabric layer are known. In many cases, such synthetic leathers have a base fabric layer made of a woven fabric, knitted fabric, or nonwoven fabric, and the surface layer is formed by thinly coating a highly flexible polyurethane resin or the like on the base fabric layer.

[0003] For example, Patent Document 1 discloses a method for producing an ultrafine fiber artificial leather, the method including the steps of: preparing a substrate from ultrafine fibers having a sea-island structure and a reinforcing layer by needle punching or water jetting, wherein all the ultrafine fibers contain a sea part and an island part; dissolving the sea part of each ultrafine fiber; and immersing the substrate in a first type of elastomer resin.

[0004] US Patent Application Publication No. 2004 / 0191412

[0005] Conventional synthetic leathers have been made to exhibit flexibility similar to that of natural leather by, for example, thinly coating a base fabric layer with a polyurethane resin, but have a significant environmental impact due to the use of petroleum-derived materials. Therefore, the present applicant proposed, in International Publication No. 2023 / 013638 and other publications, a synthetic leather in which a surface layer containing a polypeptide derivative is laminated on a base fabric layer. This synthetic leather has a surface layer composed of a biodegradable polypeptide derivative, and the polypeptide derivative includes a block copolymer having a first segment containing a polypeptide backbone and one or more second segments bonded to the first segment, and the second segment includes a molecular group having a plasticizing function for the polypeptide backbone. This ensures sufficient flexibility while reducing the environmental impact.

[0006] In this way, by laminating a surface layer containing a polymer compound with a protein structure onto a base fabric layer, it is possible to reduce the environmental impact. However, for example, to implement laminates utilizing proteins and their derivatives in society and contribute to the realization of a recycling-oriented society, it is necessary to establish a production method that allows for mass production. Furthermore, to meet a wide range of market needs, a process that can manufacture products that are thick, soft, and have a smooth surface is also necessary.

[0007] Patent Document 1 describes, as an example of a mass-production method, a method in which fibers made of polyester, nylon, or polyolefin are coated with a polyurethane resin, an acrylic resin, or a polyamide resin, and then subjected to a wet treatment including coagulation, washing, and drying. However, the present inventors have found that when a base fabric layer coated with a polymer compound containing a protein structure is subjected to a wet treatment, for example, by a method similar to that described in Patent Document 1, the surface properties of the surface layer of the resulting laminate are significantly deteriorated.

[0008] An object of the present invention is to provide a method for producing a laminate having an excellent surface quality, the laminate having a skin layer formed from a polymer compound containing a protein structure.

[0009] Representative embodiments of the present invention are described below.

[0010] <1> A method for manufacturing a laminate, the method comprising the steps of: gelling an epidermal layer-forming solution layer, which is provided in a member including a base fabric layer and an epidermal layer-forming solution layer containing a polymer compound having a protein structure and a solvent, to form an epidermal layer precursor gel on the base fabric layer; bringing the epidermal layer precursor gel into contact with a solvent displacement liquid to replace the solvent in the epidermal layer precursor gel with the solvent displacement liquid; and removing the solvent displacement liquid from the epidermal layer precursor gel to solidify the epidermal layer precursor gel, thereby forming the epidermal layer on the base fabric layer. <2> A method for manufacturing the laminate according to <1>, wherein the polymer compound is a chemically modified protein. <3> A method for manufacturing the laminate according to <1>, wherein the polymer compound is a block copolymer containing a protein structure as a segment. <4> A method for manufacturing a laminate according to any one of <1> to <3>, wherein the epidermal layer-forming solution layer contains bubbles. <5> The method for producing a laminate according to <3>, wherein the polymer compound is a block copolymer in which a segment containing a protein structure and a segment containing a molecule capable of plasticizing a protein are bonded. <6> The method for producing a laminate according to any one of <1> to <3>, further comprising the step of producing the member by applying a skin layer-forming solution onto a fabric layer. <7> The method for producing a laminate according to any one of <1> to <3>, wherein the removal of the solvent displacement liquid is carried out by drying the skin layer precursor gel. <8> The method for producing a laminate according to <6>, wherein the step of producing the member is carried out by providing the fabric layer by a roll-to-roll method and applying the skin layer-forming solution onto the fabric layer. <9> The method for producing a laminate according to any one of <1> to <3>, wherein, after the step of forming the epidermal layer precursor gel on the base fabric layer, a step of applying an epidermal layer-forming solution onto the epidermal layer precursor gel to obtain an epidermal layer-forming solution layer, and gelling the epidermal layer-forming solution layer to form an epidermal layer precursor gel is further carried out one or more times to directly form a plurality of epidermal layer precursor gels into a laminate, and then the plurality of epidermal layer precursor gels are brought into contact with a solvent displacement liquid to replace the solvent in the epidermal layer precursor gels with the solvent displacement liquid, and the solvent displacement liquid is released from each of the epidermal layer precursor gels, thereby solidifying the plurality of epidermal layer precursor gels, thereby forming the epidermal layer in a multi-layer structure.<10> The method for producing a laminate according to <9>, wherein at least one layer, excluding an outermost layer, of the plurality of skin layer-forming solution layers is a bubble-containing layer formed using the skin layer-forming solution containing bubbles.<11> The method for producing a laminate according to any one of <1> to <3>, further comprising, before the step of forming the skin layer precursor gel on the fabric layer, a step of applying an intermediate layer-forming solution onto the fabric layer to obtain an intermediate layer-forming solution layer, and a step of applying the skin layer-forming solution onto the intermediate layer-forming solution layer to produce the member, wherein the intermediate layer-forming solution layer is not gelled after the step of forming the skin layer precursor gel on the fabric layer. <12> A method for producing a laminate in which a foam layer and a skin layer are laminated on a fabric layer, the method comprising: providing a foam layer-forming solution, the foam layer-forming solution containing a polymer compound having a protein structure, a solvent, and bubbles, on the fabric layer to form a foam layer-forming solution layer on the fabric layer; gelling the foam layer-forming solution layer to form a foam layer precursor gel; providing a skin layer-forming solution, the skin layer-forming solution containing a polymer compound having a protein structure and a solvent, directly on the foam layer precursor gel to form a skin layer-forming solution layer; gelling the skin layer-forming solution layer to form a skin layer precursor gel; bringing the foam layer precursor gel and the skin layer precursor gel into contact with a solvent replacement liquid to replace the solvent in the foam layer precursor gel and the skin layer precursor gel with the solvent replacement liquid; and removing the solvent displacement liquid from the foam layer precursor gel and the skin layer precursor gel to solidify the foam layer precursor gel and the skin layer precursor gel, thereby laminating the foam layer and the skin layer on the fabric layer. <13> The method for producing a laminate according to any one of <1> to <3> and 12, wherein the laminate is synthetic leather.

[0011] According to the present invention, there is provided a method for producing a laminate having an excellent surface property, the laminate having a skin layer formed from a polymer compound containing a protein structure.

[0012] FIG. 1 is a cross-sectional view showing an outline of a laminate according to one embodiment. FIG. 2 is a graph showing the relationship between gelation time and arithmetic mean height Sa in the examples. FIG. 3 is a graph showing the relationship between gelation time and thickness variation coefficient in the examples. FIG. 4 is a scanning electron microscope image of a cross section of a synthetic leather produced in Example 1. FIG. 5 is a scanning electron microscope image of a cross section of a synthetic leather produced in Example 2. FIG. 6 is a scanning electron microscope image of a cross section of a synthetic leather produced in Comparative Example 1. FIG. 7 is a scanning electron microscope image of a cross section of a synthetic leather produced in Example 3. FIG. 8 is a scanning electron microscope image of a cross section of a synthetic leather produced in Example 4. FIG. 9 is a scanning electron microscope image of a cross section of a synthetic leather produced in Comparative Example 2. FIG. 10 is a scanning electron microscope image of a cross section of a synthetic leather produced in Example 5. FIG. 11 is a scanning electron microscope image of a cross section of a synthetic leather produced in Example 6. FIG. 12 is a scanning electron microscope image of a cross section of a synthetic leather produced in Comparative Example 3. FIG. 13 is a scanning electron microscope image of a cross section of a synthetic leather produced in Example 7. 1 is a scanning electron microscope image of the surface of the synthetic leather produced in Example 7.

[0013] The main embodiments of the present invention will be described below. However, the present invention is not limited to the explicitly described embodiments. In this specification, a numerical range expressed using the symbol "to" means a range including the numerical values ​​before and after "to" as the lower and upper limits, respectively. In this specification, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved. In this specification, unless otherwise specified, the temperature is 23°C, the pressure is 101,325 Pa (1 atmosphere), and the humidity (relative humidity) is 50% RH. In this specification, a combination of preferred aspects is a more preferred aspect.

[0014] (Laminate) A first aspect of the laminate manufacturing method according to this embodiment (hereinafter also referred to as the "first laminate manufacturing method") includes the steps of: gelling a skin layer-forming solution layer, which is provided in a member including a fabric layer and a solution layer for forming an epidermal layer, the skin layer-forming solution layer containing a polymer compound having a protein structure and a solvent, to form an epidermal layer precursor gel on the fabric layer; contacting the epidermal layer precursor gel with a solvent displacement liquid to replace the solvent in the epidermal layer precursor gel with the solvent displacement liquid; and removing the solvent displacement liquid from the epidermal layer precursor gel to solidify the epidermal layer precursor gel, thereby forming the epidermal layer on the fabric layer. The laminate manufacturing method according to this embodiment may be a laminate manufacturing method in which an intermediate layer and an epidermal layer are laminated on a fabric layer. Here, the intermediate layer may consist of a single layer or multiple layers. Furthermore, if the intermediate layer consists of a single layer, the intermediate layer may be a foamed layer containing air bubbles. In a second aspect of the method for producing a laminate according to the present embodiment (hereinafter also referred to as "second method for producing a laminate"), a method for producing a laminate in which a foam layer and a skin layer are laminated on a fabric layer includes the steps of: causing a foam layer-forming solution containing a polymer compound having a protein structure, a solvent, and bubbles to be present on the fabric layer to form a foam layer-forming solution layer on the fabric layer; gelling the foam layer-forming solution layer to form a foam layer precursor gel; and directly depositing a skin layer-forming solution containing a polymer compound having a protein structure and a solvent on the foam layer precursor gel. the foam layer precursor gel and the skin layer precursor gel are brought into contact with a solvent displacement liquid to replace the solvent in the foam layer precursor gel and the skin layer precursor gel with the solvent displacement liquid, and the foam layer precursor gel and the skin layer precursor gel are caused to separate from the solvent displacement liquid, thereby solidifying the foam layer precursor gel and the skin layer precursor gel, thereby laminating the foam layer and the skin layer on the fabric layer. Hereinafter, the first laminate manufacturing method and the second laminate manufacturing method will be collectively referred to as the "laminate manufacturing method."

[0015] As described above, the inventors have found that when a base fabric layer coated with a polymeric compound containing a protein structure is subjected to a wet treatment, for example, using a method similar to that described in Patent Document 1, the surface properties of the surface of the skin layer of the resulting laminate are significantly deteriorated. This is presumably because the polymeric compound containing a protein structure is highly water-soluble, and a portion of the polymeric compound is washed away during the wet treatment, resulting in a rough surface of the skin layer. The method for producing a laminate according to this embodiment includes gelling a layer of a solution for forming a skin layer to form a skin layer precursor gel. By adopting this embodiment, the washing away of the polymeric compound described above is suppressed, allowing the formation of a laminate having a skin layer with excellent surface properties.

[0016] The inventors also found that the outflow increases thickness unevenness of the epidermal layer. As described above, the method for producing a laminate according to this embodiment includes gelling the epidermal layer-forming solution layer to form an epidermal layer precursor gel, thereby suppressing the outflow of the polymer compound. Therefore, the method for producing a laminate according to this embodiment can also reduce thickness unevenness of the epidermal layer.

[0017] Hereinafter, embodiments of the present disclosure will be described in detail, with reference to the drawings as needed. However, the following embodiments are merely examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents.

[0018] <Method for Producing First Laminate> FIG. 1 shows an example of a laminate obtained by the first method for producing a laminate according to this embodiment.

[0019] FIG. 1 is a cross-sectional view showing a schematic of a laminate according to one embodiment. The laminate 10 shown in FIG. 1 includes a base fabric layer 2 and a skin layer 1 bonded to the base fabric layer 2. In the laminate 10 shown in FIG. 1, the skin layer 1 also functions as a shape-retaining layer for maintaining the shape of the laminate. The skin layer 1 is integrally laminated with the base fabric layer 2. For example, the skin layer 1 may be impregnated into the fibers of the base fabric layer 2. As a result, the interface between these layers may not be clearly defined. The laminate according to this embodiment may further include a layer (another layer) other than the base fabric layer and the skin layer. Examples of such a layer include an adhesive layer. A preferred embodiment of the laminate according to this embodiment is a laminate consisting of a base fabric layer and a skin layer.

[0020] <Skin Layer Precursor Gel Forming Step> The method for producing the first laminate includes a step of gelling a skin layer forming solution layer in a member including a fabric layer and the skin layer forming solution layer containing a polymer compound having a protein structure and a solvent, to form an epidermal layer precursor gel on the fabric layer (also referred to as the "skin layer precursor gel forming step").

[0021] [Fabric Layer] The fabric layer is not particularly limited, but is preferably a layer containing a fibrous substrate. The fibrous substrate may be, for example, a knitted or nonwoven fabric. The knitted or nonwoven fabric as the fibrous substrate may be composed of synthetic fibers such as polyester, polyamide, polyacrylonitrile, polyolefin, and polyvinyl alcohol; natural fibers such as cotton, linen, and silk; regenerated fibers such as rayon, staple fiber, acetate, and collagen; and artificial protein fibers such as artificial casein, collagen, and fibroin, either alone or in combination. Alternatively, the knitted or nonwoven fabric may be composed of multicomponent fibers modified into ultrafine fibers by dissolving at least one component or splitting two-component fibers, or may be fibers of a polymeric compound containing a protein structure. Such a fabric layer or the polymeric compound fibers containing a protein structure contained therein may contain known additives as needed. Examples of additives include colorants, smoothing agents, antioxidants, UV absorbers, dyes, fillers, crosslinking agents, matting agents, and leveling agents.

[0022] The knitted or woven fabric is a general term for knitted fabrics and woven fabrics. The knitted fabric may be either a knitted fabric having a weft knitting structure such as flat knitting or circular knitting (also simply referred to as a "weft knitting fabric"), or a knitted fabric having a warp knitting structure such as tricot or raschel (also simply referred to as a "warp knitting fabric"). The woven fabric may be a woven fabric having any of plain weave, twill weave, or satin weave. The knitted or woven fabric may be an unprocessed knitted or woven fabric obtained by knitting or weaving, or may be a knitted or woven fabric that has been treated with a water-repellent finish or the like after knitting or weaving.

[0023] The knitted or woven body can be obtained by knitting or weaving raw yarn. Known methods can be used for the knitting and weaving methods. Examples of knitting machines that can be used include circular knitting machines, warp knitting machines, and flat knitting machines, with circular knitting machines being preferred from the viewpoint of productivity. Flat knitting machines include molding knitting machines and seamless knitting machines, but seamless knitting machines are more preferred, particularly because they allow the production of knitted fabrics in the form of final products. Examples of looms that can be used include shuttle looms and shuttleless looms such as gripper looms, rapier looms, and air jet looms.

[0024] The raw material yarn may be a single yarn or a composite yarn (e.g., blended yarn, mixed yarn, covered yarn, etc.), or a combination of these may be used. The single yarn and composite yarn may be a spun yarn made by twisting together short fibers, or a filament yarn made by twisting together long fibers. Examples of fibers contained in the raw material yarn include synthetic fibers such as nylon, polyester, polyamide, polyacrylonitrile, polyolefin, polyvinyl alcohol, polyethylene terephthalate, and polytetrafluoroethylene; regenerated fibers such as cupra, rayon, and lyocell; natural fibers such as cotton, hemp, and silk; protein fibers; and fibers of polymer compounds containing a protein structure.

[0025] The nonwoven fabric can be produced by a known production method using the above-mentioned fibers, for example. Specifically, for example, a web (including a single-layer web and a laminated web) is formed from the above-mentioned fibers by a dry method, a wet method, an air-laid method, or the like, and then the fibers of the web are bonded by a chemical bonding method (a dipping method, a spray method, or the like) or a needle punch method, to obtain a nonwoven fabric. The nonwoven fabric can also be formed by spinning using an electrospinning method.

[0026] The numerical ranges of the fiber density (basis weight), porosity, bulk density, etc. of the nonwoven fabric are appropriately set so that they are within ranges that can sufficiently ensure waterproofness and moisture permeability. The basis weight, porosity, bulk density, etc. can be adjusted, for example, by increasing or decreasing the amount of fiber that constitutes the web, or, in the case of a laminated web, by increasing or decreasing the number of layers.

[0027] The fabric layer may further contain a polymeric substance. When the fabric layer further contains a polymeric substance, the fabric layer can be defined as a layer formed by integrating a fibrous substrate with an impregnated body made of a polymeric substance impregnated into the fibrous substrate, or as a layer formed by embedding the fibrous substrate in a layer formed of a polymeric substance.

[0028] Generally, polymeric substances are impregnated into a fibrous substrate in solution, coagulate (solidify) by removing the solvent, and remain attached to the fibers in the gaps between the fibers of the fibrous substrate. That is, the polymeric substance is integrated with the fibrous substrate as a so-called impregnated body, and together with the fibrous substrate, it constitutes the fabric layer of a laminate, interconnecting the fibers of the fibrous substrate to maintain the shape of the fabric layer and impart a predetermined strength to the fabric layer. Examples of such polymeric substances include synthetic resins such as polyvinyl chloride, polyolefins, polystyrene, polyurethane, polyester resins, epoxy resins, acrylic polymers, and acrylonitrile polymers, as well as proteins. Examples of polyurethanes include polyether-based polyurethanes, polyester-based polyurethanes, and polycarbonate-based polyurethanes, which may be used alone or in combination. Polyurethanes can be synthesized, for example, by reacting a diisocyanate with a polyol to synthesize a prepolymer, and then reacting the prepolymer with a chain extender. The diisocyanate may be an aromatic or aliphatic compound. The polyol may be, for example, polyester, polyether, polycarbonate, silicone, fluororesin, etc. Using a polyether as the polyol provides excellent hydrolysis resistance, mildew resistance, and cold resistance, while using a polycarbonate as the polyol provides excellent impact resistance, hydrolysis resistance, and mildew resistance. The chain extender may be, for example, a glycol, a diamine, a reaction terminator, etc. The polymeric substance may contain a polymeric compound containing a protein structure. By containing a polymeric compound containing a protein structure, moisture can be controlled by the moisture absorption and release properties characteristic of natural fibers, reducing unpleasant sensations such as stuffiness and stickiness, and achieving a texture closer to that of natural leather. Such polymeric substances may contain known additives as necessary. Examples of additives include colorants, smoothing agents, antioxidants, UV absorbers, dyes, fillers, crosslinking agents, matting agents, leveling agents, etc.

[0029] The base fabric layer may be a porous layer, which makes it possible to achieve a more voluminous feel.

[0030] The thickness of the base fabric layer may be, for example, 100 to 2000 μm, 100 to 1000 μm, 500 to 1000 μm, or 500 to 750 μm.

[0031] [Skin Layer Forming Solution Layer] The skin layer forming solution layer contains a polymer compound containing a protein structure and a solvent.

[0032] The details of the polymer compound containing a protein structure will be described later. As the solvent, a solvent capable of dissolving the polymer compound containing a protein structure is preferred, and examples thereof include organic solvents such as dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), formic acid, alcohol, and hexafluoroisopropanol (HFIP). Among these, dimethyl sulfoxide is preferred.

[0033] In order to increase the solubility of the polymer compound, the solution layer for forming the surface layer may contain an inorganic salt. Examples of the inorganic salt include alkali metal halides (e.g., LiCl, LiBr, etc.), alkaline earth metal halides (e.g., CaCl, etc.), and the like. ２ ), alkaline earth metal nitrates (e.g., Ca(NO3)2), and sodium thiocyanate (e.g., NaSCN). When the total amount of dissolved components is taken as 100% by mass, the proportion of inorganic salts is preferably in the range of 0.1 to 20% by mass.

[0034] The content of the polymer compound containing a protein structure relative to the total mass of the epidermal layer forming solution layer is not particularly limited, but is preferably 1 to 45 mass %, more preferably 3 to 30 mass %, and even more preferably 5 to 25 mass %.

[0035] The skin layer-forming solution layer may contain air bubbles. Hereinafter, a skin layer-forming solution layer containing air bubbles will also be referred to as a "bubble-containing layer." The inclusion of air bubbles allows the skin layer to be formed as a porous layer. Air bubbles can be introduced into the skin layer-forming solution layer by stirring the skin layer-forming solution to form the skin layer-forming solution layer, foaming with a foaming agent, a casting method, or the like. The amount of air bubbles is not particularly limited, and can be, for example, 1 to 90 vol %, 20 to 80 vol %, or 30 to 75 vol % relative to the total volume of the skin layer-forming solution layer. Furthermore, the apparent density of the skin layer when air bubbles are contained (i.e., the density including the volume of the air bubbles in a unit volume) is 0.1 to 1.13 g / cm ３ ,0.2~0.9g / cm ３ , or 0.3 to 0.8 g / cm ３ It can be said that:

[0036] The skin layer-forming solution layer may contain a foaming agent, which can cause foaming during gelation or drying, making the solution layer porous.

[0037] The skin layer-forming solution layer may contain known additives as needed, such as colorants, smoothing agents, antioxidants, ultraviolet absorbers, dyes, fillers, crosslinking agents, matting agents, and leveling agents.

[0038] The member including the fabric layer and the skin layer-forming solution layer containing the polymer compound having a protein structure and a solvent is preferably produced by applying the skin layer-forming solution onto the fabric layer. That is, the method for producing the first laminate preferably further includes, before the skin layer precursor gel-forming step, a step of applying the skin layer-forming solution onto the fabric layer to produce the member (also referred to as a "skin layer-forming solution layer-producing step").

[0039] The epidermal layer forming solution preferably contains a polymer compound containing a protein structure and a solvent. Other details of the components contained in the epidermal layer forming solution are the same as the details of the components contained in the epidermal layer forming solution layer described above.

[0040] The coating method for applying the skin layer-forming solution to the fabric layer is not particularly limited, and any known method can be used. Examples include a curtain coater method in which a coating solution is supplied through multiple slits to supply the skin layer-forming solution in a curtain-like manner, a die coater method in which the skin layer-forming solution is supplied through multiple slits, a roll coating method, and a bar coating method. In one preferred aspect of this embodiment, the step of manufacturing the component is performed by providing the fabric layer using a roll-to-roll method and applying the skin layer-forming solution to the fabric layer.

[0041] [Gelling] Examples of a method for gelling the skin layer-forming solution layer to obtain a skin layer precursor gel include, but are not particularly limited to, leaving the solution to stand, cooling (to solidify the solvent), heating, solidifying the solution by applying steam, and removing the solvent to increase the solid content.

[0042] In the case of leaving the mixture to stand, the time for leaving the mixture to stand is not particularly limited, but is preferably 30 seconds or more, more preferably 5 minutes or more, and even more preferably 10 minutes or more. The upper limit of the time is not particularly limited, but can be, for example, 24 hours or less, 180 minutes or less, or 60 minutes or less.

[0043] In this embodiment, gelation refers to a state in which the solvent is contained and the fluidity is lost, so that the solution does not flow even when tilted, and preferably a state in which the viscosity is 50,000 mPa s or more. The viscosity is the arithmetic mean value measured for 10 minutes using a rotational rheometer (Kinexus pro+) with a cone and plate geometry (CP1 / 40:PLS55) at a measurement temperature of 25°C, a measurement frequency of 5 Hz, and a sampling interval of 5 seconds.

[0044] <Substitution Step> The method for producing a first laminate according to this embodiment includes a step of contacting the epidermal layer precursor gel with a solvent-substitution liquid to substitute the solvent in the epidermal layer precursor gel with the solvent-substitution liquid (also referred to as the "substitution step"). The solvent-substitution liquid is not particularly limited, but is preferably a solvent that mixes with the solvent contained in the epidermal layer precursor gel and that does not easily dissolve the polymer, such as water. Specifically, the solubility of the solvent contained in the epidermal layer precursor gel in the solvent-substitution liquid is preferably 10 g / 100 mL or more, more preferably 15 g / 100 mL or more, and even more preferably 20 g / 100 mL or more. The upper limit is not particularly limited, and the solvent contained in the epidermal layer precursor gel may be mixed with the solvent-substitution liquid in any desired combination. In this specification, solubility is measured at 25°C and 1 atmosphere unless otherwise specified.

[0045] From the viewpoint of removability of the substituted solvent, the boiling point of the solvent replacement liquid is preferably lower than the boiling point of the solvent contained in the epidermal layer precursor gel, more preferably not higher than 150, and even more preferably not higher than 100. In this specification, boiling points are values ​​at 1 atmosphere unless otherwise specified.

[0046] From the viewpoint of the volatility of the solvent to be replaced, the saturated vapor pressure of the solvent replacement liquid is preferably higher than the saturated vapor pressure of the solvent contained in the epidermis layer precursor gel, more preferably equal to or higher than 5.0 Pa, and even more preferably equal to or higher than 10.0 Pa. In this specification, the saturated vapor pressure is the value at 25°C and 1 atmosphere unless otherwise specified.

[0047] The solvent replacement liquid may contain multiple types of solvents. For example, a mixed solvent containing water and DMSO may be used as the solvent replacement liquid. In particular, when the epidermal layer precursor gel contains DMSO, using a mixed solvent containing water and DMSO as the solvent replacement liquid may reduce the replacement rate and further improve the surface properties.

[0048] The substitution method using a solvent substitution liquid is not limited as long as it brings the solvent substitution liquid into contact with the skin layer precursor gel, and examples thereof include a method of immersing the skin layer precursor gel in the solvent substitution liquid. For example, when the component is manufactured by providing a fabric layer using a roll-to-roll method and applying the skin layer-forming solution to the fabric layer, the substitution step can be performed by a method in which the component is gelled while being transported by the roll, and the fabric layer including the skin layer precursor gel after the gelation is immersed in the solvent substitution liquid.

[0049] The temperature during the substitution is not particularly limited, but may be 15°C or higher, 20°C or higher, 25°C or higher, or the like. Furthermore, the substitution may be performed at 90°C or lower, 85°C or lower, 80°C or lower, or the like. The pressure during the substitution is not particularly limited, and the substitution may be performed under increased pressure or reduced pressure, or may be performed without increased pressure or reduced pressure. Furthermore, the substitution operation may be performed multiple times, with the solvent substitution liquid being replaced with a new one.

[0050] <Laminate Formation Step> The first laminate manufacturing method of this embodiment includes a step of laminating the epidermis layer on the fabric layer by removing the solvent-replacement liquid from the epidermis layer precursor gel and solidifying the epidermis layer precursor gel (also referred to as the "laminate formation step"). The solvent-replacement liquid is removed from the epidermis layer precursor gel, solidifying it, and remaining in a state of being fixed to the fabric layer. The removal of the solvent-replacement liquid is preferably performed by drying the epidermis layer precursor gel.

[0051] The drying conditions are not particularly limited, but can be, for example, a drying temperature of 25°C or higher, 50°C or higher, 80°C or higher, 100°C or higher, or the like. Also, drying can be performed at 200°C or lower, 150°C or lower, 130°C or lower, or the like. Furthermore, drying can be performed for 5 minutes or more, 10 minutes or more, 20 minutes or more, 30 minutes or more, or the like. Furthermore, drying can be performed for 180 minutes or less, 120 minutes or more, 90 minutes or less, or the like. Furthermore, drying can be performed under reduced pressure, or by vacuum freeze drying or the like.

[0052] <Formation of Multiple Layers> In the first laminate manufacturing method of the present embodiment, after the step of forming the epidermal layer precursor gel on the base fabric layer (epidermal layer precursor gel-forming step), a step of applying an epidermal layer-forming solution to the epidermal layer precursor gel to obtain an epidermal layer-forming solution layer, and gelling the epidermal layer-forming solution layer to form an epidermal layer precursor gel (also referred to as an "another epidermal layer precursor gel-forming step") may be carried out one or more times to directly form a plurality of epidermal layer precursor gels as a laminate, and then the plurality of epidermal layer precursor gels may be brought into contact with a solvent displacement liquid to replace the solvent in the epidermal layer precursor gels with the solvent displacement liquid, and the solvent displacement liquid may be released from each of the epidermal layer precursor gels to solidify the plurality of epidermal layer precursor gels, thereby forming the epidermal layer in a multi-layer structure.

[0053] The other epidermal layer precursor gel-forming step can be carried out in the same manner as the above-described epidermal layer precursor gel-forming step, except that the epidermal layer-forming solution is applied to the epidermal layer precursor gel. The epidermal layer-forming solution layer formed in the other epidermal layer precursor gel-forming step may be the same as or different from the epidermal layer-forming solution layer in the above-described epidermal layer precursor gel-forming step in terms of the types and proportions of its constituent components. For example, the epidermal layer-forming solution layer formed in the other epidermal layer precursor gel-forming step may be formed as a layer containing air bubbles, and the epidermal layer-forming solution layer in the above-described epidermal layer precursor gel-forming step may be formed as a layer not containing air bubbles. Furthermore, the polymer compounds containing protein structures contained in these layers may have different structures or molecular weights.

[0054] The solvent substitution and removal in the above embodiment can be carried out according to the methods described in the substitution step and the laminate formation step, respectively.

[0055] It is also preferred that at least one layer, excluding the outermost layer, of the plurality of skin layer-forming solution layers is a bubble-containing layer formed using the skin layer-forming solution containing bubbles. The outermost layer refers to the layer farthest from the substrate among the skin layer-forming solution layers. This embodiment provides a laminate that is excellent in terms of surface properties, flexibility, and weight reduction.

[0056] The method for manufacturing a laminate may further include, before the step of forming the skin layer precursor gel on the fabric layer, a step of applying an intermediate layer forming solution to the fabric layer to obtain an intermediate layer forming solution layer, and a step of applying the skin layer forming solution to the intermediate layer forming solution layer to manufacture the member, wherein the intermediate layer forming solution layer is not gelled after the step of forming the skin layer precursor gel on the fabric layer. According to this embodiment, a laminate having one or more intermediate layers between the fabric layer and the skin layer can be obtained. Here, by forming the skin layer precursor gel on the intermediate layer forming solution layer without gelling the intermediate layer forming solution layer, surface properties can be improved. Furthermore, in this embodiment, when the intermediate layer consists of a single layer, the intermediate layer may be a foamed layer containing bubbles. When the intermediate layer consists of multiple layers, at least one of the layers may be a foamed layer. Preferred embodiments of the intermediate layer forming solution and the intermediate layer forming solution layer are the same as those of the skin layer forming solution and the skin layer forming solution layer described above. In this embodiment, the surface properties may be further improved by forming a relatively thick skin layer, even if the intermediate layer is not gelled. For example, the thickness of the skin layer may be 5 to 500 μm, or even 30 to 300 μm.

[0057] [Other Steps] The method for producing a laminate according to this embodiment may further include other steps in addition to the steps described above. These other steps include, after the laminate formation step, a step of surface treating the surface of the skin layer on the side opposite the fabric layer, a step of adhering a sheet or film-like molded article to the resulting laminate, and a step of cutting the resulting laminate. These steps can be performed by methods known in the art.

[0058] <Polymer Compound Containing Protein Structure> The polymer compound containing a protein structure may be a protein or a chemically modified protein. Chemically modified proteins include protein derivatives in which other structures are bound to the protein structure, and proteins modified using a reactive functional group such as a hydroxyl group as the starting point of the reaction. Furthermore, the protein derivative may be a protein derivative in which other structures are bound to a protein modified using a reactive functional group such as a hydroxyl group as the starting point of the reaction. Details of protein derivatives will be described later. Proteins modified using a reactive functional group such as a hydroxyl group as the starting point of the reaction include, for example, proteins in which the hydroxyl group of a serine residue, threonine residue, or tyrosine residue in the protein, the amino group of a lysine residue, or the sulfhydryl group of a cysteine ​​residue in the protein is acylated. Particularly, chemically modified proteins include esterified proteins. Examples of esterified proteins include maleate-esterified proteins, succinate-esterified proteins, sulfonate-esterified proteins, and phosphate-esterified proteins. Chemical modification can be performed by methods well known to those skilled in the art, for example, by the method described in WO 2021 / 187502. For example, a method is known in which an amino acid sequence is chemically modified by a 1,4-addition reaction of a mercapto group of cysteine ​​with a compound having a carbon-carbon double bond, such as maleimide. Chemical modification can also be performed by alkylating a guanidine group, an amide group, or a hydroxy group, or by acylating a hydroxy group. Because the reaction conditions are relatively mild, it is preferable to bind other structures by reacting a cysteine ​​residue with maleimide.

[0059] [Artificial Protein] As the protein, an artificial protein is preferred. Here, artificial proteins include recombinant proteins and synthetic proteins. In other words, in this specification, "artificial protein" means a protein produced artificially. An artificial protein may have a domain sequence different from the amino acid sequence of a naturally occurring protein, or it may have the same amino acid sequence as a naturally occurring protein. Furthermore, an "artificial protein" may use the amino acid sequence of a naturally occurring protein as is, or may be a protein whose amino acid sequence has been modified based on the amino acid sequence of a naturally occurring protein (e.g., a protein whose amino acid sequence has been modified by modifying the gene sequence of a cloned naturally occurring protein), or may be a protein artificially designed and synthesized without relying on a naturally occurring protein (e.g., a protein having a desired amino acid sequence obtained by chemically synthesizing a nucleic acid encoding a designed amino acid sequence).

[0060] Furthermore, examples of artificial proteins include proteins that can be used for industrial purposes. "Usable for industrial purposes" means that the protein can be used, for example, in various general-purpose materials for indoor and outdoor use. Specific examples of artificial proteins that can be used for industrial purposes include artificial structural proteins.

[0061] [Artificial structural proteins] Structural proteins refer to proteins involved in the structure of living organisms, proteins that constitute structures produced by living organisms, or proteins derived therefrom. Artificial structural proteins also refer to proteins that self-aggregate under certain conditions to form structures such as fibers, films, resins, gels, micelles, and nanoparticles. Furthermore, artificial structural proteins can also be said to be proteins that contain repeated motifs consisting of a characteristic amino acid sequence or a specific number of amino acid residues and form the skeleton of an organism or material. Artificial structural proteins are artificially produced versions of these structural proteins. Examples of such artificial structural proteins include artificial fibroin, artificial keratin, artificial collagen, artificial elastin, and artificial resilin.

[0062] When forming artificial structural proteins, amino acids with relatively small side chains are more likely to form hydrogen bonds and thus produce stronger molded products. Furthermore, alanine and glycine residues are amino acids with nonpolar side chains, and therefore are arranged so that they face inward during the folding process of protein production, making them more likely to form α-helix or β-sheet structures. Therefore, a high proportion of amino acids such as glycine and alanine residues is desirable. From the viewpoint of obtaining molded products with superior strength, the alanine residue content may be, for example, 10-40%, and may be 12-40%, 15-40%, 18-40%, 20-40%, or 22-40%. From the viewpoint of obtaining molded products with superior strength, the glycine residue content may be, for example, 10-55%, and may be 11-55%, 13-55%, 15-55%, 18-55%, 20-55%, 22-55%, or 25-55%.

[0063] As used herein, the term "alanine residue content" refers to the number of alanine residues relative to the total number of amino acid residues constituting a protein, and is a value expressed by the following formula:

[0064] Alanine residue content = (number of alanine residues contained in protein / total number of amino acid residues in protein) x 100 (%)

[0065] Furthermore, the glycine residue content, serine residue content, threonine residue content, proline residue content, and tyrosine residue content have the same meaning as those obtained by replacing the alanine residue in the above formula with glycine residue, serine residue, threonine residue, proline residue, and tyrosine residue, respectively.

[0066] It is preferable that the artificial structural protein contains amino acids with relatively large side chains or flexible amino acids uniformly throughout its entire sequence to a certain extent. Specifically, the structural protein may contain a motif containing tyrosine, threonine, and proline residues in a repeated cycle. Such a structural protein is likely to inhibit the formation of strong intermolecular hydrogen bonds during processing of the molded article obtained by molding, thereby improving processability. For example, the total content of proline, threonine, and tyrosine residues in any 20 consecutive amino acid residues may be 5% or more, more than 5.5%, 6.0% or more, more than 6.5%, 7.0% or more, more than 7.5%, 8.0% or more, more than 8.5%, 9.0% or more, 10.0% or more, or 15.0% or more. Furthermore, for example, the total content of proline, threonine, and tyrosine residues in any 20 consecutive amino acid residues may be 50% or less, 40% or less, 30% or less, or 20% or less.

[0067] The artificial structural protein may have an amino acid sequence that includes a repeat sequence. That is, the artificial structural protein according to this embodiment may have multiple amino acid sequences (repeat sequence units) with high sequence identity within the artificial structural protein. The number of amino acid residues in the repeat sequence unit is preferably 6 to 200. Furthermore, the sequence identity between the repeat sequence units may be, for example, 85% or more, 90% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more. The hydrophobicity index (hydropathy index) of the repeating sequence unit may be, for example, -0.80 or more, -0.70 or more, -0.60 or more, -0.50 or more, -0.40 or more, -0.30 or more, -0.20 or more, -0.10 or more, 0.00 or more, 0.22 or more, 0.25 or more, 0.30 or more, 0.35 or more, 0.40 or more, 0.45 or more, 0.50 or more, 0.55 or more, 0.60 or more, 0.65 or more, or 0.70 or more. The upper limit of the hydrophobicity index of the repeating sequence unit is not particularly limited, but may be, for example, 1.0 or less or 0.7 or less.

[0068] The artificial structural protein is (A) ｎThe amino acid sequence may include an amino acid sequence containing the motif. ｎ The motif means an amino acid sequence mainly consisting of alanine residues. (A) ｎ The number of amino acid residues in the motif may be an integer of 2 to 27, or may be an integer of 2 to 20, 2 to 16, or 2 to 12. 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, 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 Preferably, the artificial structural protein contains a plurality of motifs. ｎ When there are multiple motifs, their (A) ｎ The motifs may have the same amino acid sequence or different amino acid sequences. ｎ The amino acid sequence containing the motif is preferably different from the amino acid sequence of a naturally occurring protein. ｎ The amino acid sequence of the present invention is different from the amino acid sequence of a naturally occurring protein, and (A) ｎ The motif represents an amino acid sequence consisting of 2 to 27 amino acid residues, and (A) ｎ In another preferred embodiment of the present invention, the number of alanine residues in the motif is 40% or more of the total number of amino acid residues. ｎ Preferred embodiments of the motif are as described above.

[0069] The artificial structural protein may be artificial fibroin. Examples of fibroin include naturally occurring fibroin. Examples of naturally occurring fibroin include fibroin produced by insects or spiders. Natural fibroin is a fibrous protein with a molecular weight of approximately 370,000, composed of two subunits, and has a high content of glycine, alanine, serine, and tyrosine residues, with these amino acid residues accounting for nearly 90% of the total number of amino acid residues. Natural fibroin has a crystalline region rich in amino acid residues with relatively small side chains such as glycine, alanine, and serine, and an amorphous region containing amino acid residues with relatively large side chains such as tyrosine.

[0070] More specific examples of naturally occurring fibroins include fibroins whose sequence information is registered in NCBI GenBank. For example, among the sequences registered in NCBI GenBank that contain INV as a division, the sequence can be confirmed by extracting sequences in which spidroin, ampullate, fibroin, "silk and polypeptide," or "silk and protein" are described as keywords in the DEFINITION, a specific product character string from the CDS, or a specific character string in the TISSUE TYPE from the SOURCE.

[0071] As used herein, "artificial fibroin" refers to artificially produced fibroin (artificial fibroin). The artificial fibroin may be a fibroin with an amino acid sequence different from that of naturally occurring fibroin, or may be a fibroin with the same amino acid sequence as that of naturally occurring fibroin. Artificial fibroin can be produced by known methods, for example, by the method described in International Publication No. 2019 / 194263. When the modified fibroin is expressed by forming an insoluble body within cells, the host cells are similarly recovered, disrupted, and centrifuged to recover the insoluble body of the modified fibroin as a precipitate fraction. The recovered insoluble body of the modified fibroin may be inactivated by adding citric acid and water (e.g., at 80°C for 2 hours), washed with water by filter press filtration, granulated, and dried to obtain a purified sample.

[0072] Artificial fibroin may be a fibrous protein having a structure similar to that of naturally occurring fibroin, or may be a fibroin having a sequence similar to the repetitive sequence of naturally occurring fibroin. The "similar sequence to the repetitive sequence of fibroin" may be a sequence actually found in naturally occurring fibroin, or a sequence similar thereto.

[0073] "Artificial fibroin" may be a naturally occurring fibroin whose amino acid sequence has been modified (e.g., an amino acid sequence modified by modifying the gene sequence of a cloned naturally occurring fibroin), as long as it has the amino acid sequence specified in this disclosure. Alternatively, it may be an artificially designed amino acid sequence independent of naturally occurring fibroin (e.g., an artificial fibroin having a desired amino acid sequence obtained by chemically synthesizing a nucleic acid encoding a designed amino acid sequence). Artificial fibroins whose amino acid sequence has been modified are also included in the category of artificial fibroin, provided that the amino acid sequence differs from that of naturally occurring fibroin. Examples of artificial fibroins include artificial silk fibroin (a silk protein produced by silkworms) and artificial spider silk fibroin (a spider silk protein produced by spiders) whose amino acid sequence has been modified. Because artificial fibroin is relatively easy to fibrillate and has high fiber-forming ability, it is preferable for the molding material to contain, and more preferably consist of, artificial spider silk fibroin.

[0074] Artificial fibroin has the formula 1: [(A) ｎ motif-REP] ｍ , or Formula 2: [(A) ｎ motif-REP] ｍ -(A) ｎ The artificial fibroin may be a protein containing a domain sequence represented by a motif. The artificial 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 C-terminal sequence are typically, but are not limited to, regions that do not have repeats of the amino acid motif characteristic of fibroin and consist of about 100 amino acid residues.

[0075] As used herein, a "domain sequence" refers to a sequence of a molecule having the formula 1: [(A) ｎ motif-REP] ｍ , or Formula 2: [(A) ｎ motif-REP] ｍ -(A) ｎThe amino acid sequence represented by the motif (A) ｎ The motif represents an amino acid sequence mainly consisting of alanine residues, and the number of amino acid residues is an integer between 2 and 27. (A) ｎ The number of amino acid residues in the motif may be an integer of 2 to 27, 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 also 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) ｎ The motifs may have the same or different amino acid sequences, and the multiple REPs may have the same or different amino acid sequences.

[0076] Specific examples of artificial fibroins include, for example, an artificial fibroin derived from a major spinal dragline silk protein produced in the major ampullate gland of spiders (first artificial fibroin) as described in WO 2019 / 194263, an artificial fibroin having a domain sequence with a reduced content of glycine residues (second artificial fibroin), (A) ｎ An artificial fibroin having a domain sequence with a reduced motif content (third artificial fibroin), a glycine residue content, and (A) ｎThese include an artificial fibroin with a reduced motif content (fourth artificial fibroin), an artificial fibroin with a domain sequence containing a region with a locally high hydrophobic index (fifth artificial fibroin), and an artificial fibroin with a domain sequence with a reduced content of glutamine residues (sixth artificial fibroin). The definitions of the first to sixth artificial fibroins are set forth in WO 2019 / 194263, the contents of which are incorporated herein by reference.

[0077] The artificial fibroin may contain a tag sequence at either or both of the N-terminus and C-terminus, which allows the artificial fibroin to be isolated, immobilized, detected, visualized, and the like.

[0078] An example of a tag sequence is an affinity tag that utilizes specific affinity (binding property, affinity) with other molecules. A specific example of an affinity tag is a histidine tag (His tag). A His tag is a short peptide consisting of approximately 4 to 10 histidine residues, and has the property of specifically binding to metal ions such as nickel, so it can be used to isolate artificial fibroin by chelating metal chromatography. A specific example of a tag sequence is the amino acid sequence shown in SEQ ID NO: 8 (an amino acid sequence including a His tag sequence and a hinge sequence).

[0079] 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.

[0080] Furthermore, an "epitope tag" that utilizes an antigen-antibody reaction can also be used. By adding an antigenic peptide (epitope) as a tag sequence, an antibody specific to 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, artificial fibroin can be easily purified with high specificity.

[0081] 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 artificial fibroin from which the tag sequence has been cleaved can be recovered.

[0082] Specific examples of artificial fibroins include those represented by SEQ ID NOS: 1 to 7. The artificial fibroin may be an artificial fibroin represented by SEQ ID NOS: 1 to 7 or an artificial fibroin containing an amino acid sequence having 90% or more sequence identity with these amino acid sequences. The respective contents of alanine residues, glycine residues, serine residues, threonine residues, tyrosine residues, glutamine residues, and lysine residues in the artificial fibroins represented by SEQ ID NOS: 1 to 7 are shown in Table 1 below. The artificial fibroins represented by SEQ ID NOS: 1 and 7 correspond to the aforementioned fourth artificial fibroin, the artificial fibroins represented by SEQ ID NOS: 2, 3, 5, and 6 correspond to the aforementioned sixth artificial fibroin, and the artificial fibroin represented by SEQ ID NOS: 4 corresponds to the aforementioned first artificial fibroin.

[0083] (Table 1)

[0084] The artificial fibroin may be an artificial fibroin having at least two or more characteristics of the first artificial fibroin, the second artificial fibroin, the third artificial fibroin, the fourth artificial fibroin, the fifth artificial fibroin, and the sixth artificial fibroin.

[0085] The molecular weight of the artificial fibroin according to this embodiment is not particularly limited, and may be, for example, 2 kDa or more and 700 kDa or less. The molecular weight of the artificial fibroin according to this embodiment may be, for example, 2 kDa or more, 3 kDa or more, 4 kDa or more, 5 kDa or more, 6 kDa or more, 7 kDa or more, 8 kDa or more, 9 kDa or more, 10 kDa or more, 20 kDa or more, 30 kDa or more, 40 kDa or more, 50 kDa or more, 60 kDa or more, 70 kDa or more, 80 kDa or more, 90 kDa or more, or 100 kDa or more, or 700 kDa or less, 600 kDa or less, 500 kDa or less, 400 kDa or less, less than 360 kDa, 300 kDa or less, or 200 kDa or less.

[0086] [Protein Derivative] The protein derivative is preferably a block copolymer containing a protein structure as a segment, more preferably a block copolymer in which a segment containing a protein structure is bonded to a segment containing a molecule capable of plasticizing a protein, and even more preferably a block copolymer having a first segment containing a protein structure and one or more second segments bonded to the first segment. The second segment preferably contains a molecular group that has the function of plasticizing the protein structure. The number of second segments per first segment is one or more, preferably 2 or more, more preferably 2 to 10, even more preferably 2 to 8, particularly preferably 2 to 6, and most preferably 2 to 4.

[0087] A block copolymer having a first segment and a second segment may be, for example, one in which one or more second segments are bonded to one first segment, or may be one in which multiple blocks each including a first segment and a second segment bonded to the first segment are linked together. The block copolymer contained in the polymer compound containing a protein structure may be a polymer (e.g., a graft polymer) having a first segment containing a protein structure as the main chain and a second segment as a side chain. The block copolymer may, for example, have multiple first segments, with the first segments and the second segments bonded alternately. The alternating bonding of the first segments and the second segments may further improve the toughness of the laminate, for example.

[0088] The block copolymer may have a plurality of the first segments, and a portion of the second segments may be bonded to two or more of the first segments to form a network structure. The network structure can further improve the toughness of the laminate.

[0089] The bond between the first segment and the second segment may be a direct bond, or may be a bond via a structure that allows bonding between the first segment and the second segment. In any of these bonding forms, the bond between the first segment and the second segment may be a coordinate bond, a bond due to ionic interaction, or a covalent bond. Among these, a covalent bond is preferred.

[0090] [First Segment] The first segment may include a protein structure, and may, for example, consist solely of a protein structure. The first segment may be bound to the second segment via a functional group (e.g., a thiol group of cysteine) in the amino acid sequence constituting the protein structure. In other words, any recombinant protein structure or hydrophobic protein structure having a functional group capable of binding to the second segment can be used as the protein structure. In this case, the number of functional groups possessed by the protein structure may be, for example, one or more, two or more, or four or more. The number of functional groups possessed by the protein structure may be, for example, 30 or less, 25 or less, 20 or less, 15 or less, 10 or less, or 8 or less. The number of functional groups possessed by the protein structure can be adjusted within the above-mentioned ranges and may be, for example, 1 to 30, 1 to 25, 1 to 20, 1 to 15, 1 to 10, 1 to 8, or 2 to 8. The first segment may be bound to the second segment via a functional group introduced into a functional group in the amino acid sequence that constitutes the protein structural framework.

[0091] The functional group as described above may be, for example, at least one selected from the group consisting of a thiol group, an amino group, a hydroxy group, a guanidino group, a carboxy group, a phenoxy group, an indole group, an amide group, an azide group, and an alkynyl group, preferably at least one selected from the group consisting of a thiol group, an amino group, a hydroxy group, a guanidino group, a carboxy group, a phenoxy group, an indole group, and an amide group, more preferably at least one selected from the group consisting of a thiol group, an amino group, a hydroxy group, a guanidino group, a carboxy group, a phenoxy group, and an indole group, and even more preferably at least one selected from the group consisting of a thiol group, an amino group, a hydroxy group, a guanidino group, a carboxy group, a phenoxy group, and an indole group. The amino group may be at least one selected from the group consisting of an anidino group, a carboxy group, and a phenoxy group, more preferably at least one selected from the group consisting of a thiol group, an amino group, a hydroxy group, a guanidino group, and a carboxy group, even more preferably at least one selected from the group consisting of a thiol group, an amino group, a hydroxy group, and a guanidino group, particularly preferably at least one selected from the group consisting of a thiol group, an amino group, and a hydroxy group, particularly preferably at least one selected from the group consisting of a thiol group and an amino group, and most preferably a thiol group. The amino group may be, for example, the amino group contained in lysine. The hydroxy group may be, for example, the hydroxy group contained in serine, the hydroxy group contained in threonine, etc. The guanidino group may be, for example, the guanidino group contained in arginine. The carboxy group may be, for example, the carboxy group contained in glutamic acid, the carboxy group contained in aspartic acid, etc. The phenoxy group may be, for example, the phenoxy group possessed by tyrosine. The indole group may be, for example, the indole group possessed by tryptophan. The amide group may be, for example, the amide group possessed by glutamine, the amide group possessed by asparagine, etc. The alkynyl group may be an alkynyl group introduced by reacting a thiol group possessed by cysteine ​​with an acetylene halide.

[0092] The protein structure contained in the first segment is also preferably a protein structure formed using a reactive functional group such as the above-mentioned hydroxyl group as the starting point of the reaction. In particular, a protein in which at least some or all of the lysine, serine, threonine, tyrosine, or cysteine ​​residues in the raw protein are acylated is preferred. That is, the raw protein preferably has at least one lysine, serine, threonine, tyrosine, or cysteine ​​residue in its amino acid sequence. When the protein structure contained in the first segment contains at least one nucleophilic functional group such as a serine, threonine, tyrosine, lysine, or cysteine ​​residue, it is preferred that the hydroxyl group of the serine, threonine, or tyrosine residue, the amino group of the lysine residue, or the sulfhydryl group of the cysteine ​​residue be acylated. When the protein structure contains a serine, threonine, or tyrosine residue, it can be more efficiently acylated by an acylating agent. When taking into consideration the improvement in the reactivity of the protein structure with the acylating agent, the improvement in productivity of the modified protein, etc., the protein structure may have a total content of serine residues, threonine residues, and tyrosine residues (the ratio of the total number of serine residues, threonine residues, and tyrosine residues to the total number of amino acid residues) of, for example, 4% or more, 4.5% or more, 5% or more, 5.5% or more, 6% or more, 6.5% or more, or 7% or more. Note that the upper limit of the total content of serine residues, threonine residues, and tyrosine residues is not particularly limited, but considering the amino acid composition of various proteins that can be suitably used as the protein and modified protein according to this embodiment, it may be, for example, 35% or less, 33% or less, 30% or less, 25% or less, or 20% or less.

[0093] The acylating agent may be any reagent capable of acylating a hydroxyl group, an amino group, or a sulfhydryl group, such as activated carboxylic acid derivatives, such as carboxylic acid halides (e.g., carboxylic acid chlorides and carboxylic acid bromides) and carboxylic acid anhydrides (e.g., acid anhydrides and cyclic acid anhydrides). These acylating agents introduce an acyl group corresponding to the carboxylic acid. Examples of carboxylic acids include saturated monocarboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid (heptanoic acid), caprylic acid (octanoic acid), pelargonic acid (nonanoic acid), capric acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, and isostearic acid; unsaturated monocarboxylic acids such as oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid; and dicarboxylic acids such as maleic acid. Examples of acid halides corresponding to these carboxylic acids include acetyl chloride, acetyl bromide, propionyl chloride, propionyl bromide, lauroyl chloride, myristoyl chloride, palmitoyl chloride, stearoyl chloride, etc. Examples of acid anhydrides corresponding to these carboxylic acids include acetic anhydride, propionic anhydride, maleic anhydride, etc.

[0094] The amount of acylating agent used may be 1.5 to 7 equivalents per nucleophilic functional group contained in the protein structure. The amount of acylating agent used may preferably be 1.5 to 6.5 equivalents, 1.5 to 6 equivalents, 1.5 to 5.5 equivalents, 1.5 to 5 equivalents, 1.5 to 4 equivalents, 2 to 7 equivalents, 2 to 6.5 equivalents, 2 to 6 equivalents, 2 to 5.5 equivalents, 2 to 5 equivalents, 2 to 4.5 equivalents, 2.5 to 7 equivalents, 2.5 to 6.5 equivalents, 2.5 to 6 equivalents, 2.5 to 5.5 equivalents, 2.5 to 5 equivalents, or 2.5 to 4.5 equivalents per nucleophilic functional group. "Equivalent per nucleophilic functional group" refers to the molar equivalent of the acylating agent per nucleophilic functional group contained in the protein. By setting the amount of the acylating agent used within the above range, the reactivity or reaction efficiency between the protein and the acylating agent in, for example, mechanochemical treatment is increased, and the desired modified protein can be obtained more efficiently. Details of the mechanochemical treatment will be described later. In this embodiment, the protein can be chemically modified by mixing the above-mentioned protein with the acylating agent and treating the resulting mixture by the mechanochemical method.

[0095] The molecular weight of the first segment is, for example, preferably 200 to 1,000,000, more preferably 300 to 900,000, even more preferably 400 to 800,000, still more preferably 500 to 700,000, even more preferably 600 to 600,000, particularly preferably 1,000 to 600,000, even more preferably 3,000 to 600,000, even more preferably 5,000 to 600,000, even more preferably 10,000 to 600,000, and even more preferably 10,000 to 100,000.

[0096] When the molecular weight of the first segment is 200 or more, the first segment that functions as a hard segment relative to the second segment (soft segment) containing a molecular group with plasticizing function becomes sufficiently large. In this case, the rigidity of a laminate formed using a polymer compound containing a protein structure becomes sufficiently large, making it easier to use as a laminate material. When the molecular weight of the first segment is 1,000,000 or less, a decrease in the reactivity of the linking reaction is suppressed, making it easier to complete the reaction within a time period that allows commercial production of the material from a chemical engineering perspective. As a result, it becomes easier to suppress the localization of unreacted second segments remaining in the laminate material.

[0097] The molecular weight of the first segment and the molecular weight of the protein structural backbone contained in the first segment may be, for example, 1,000 or more, 2,000 or more, 3,000 or more, 4,000 or more, 5,000 or more, 6,000 or more, 7,000 or more, 8,000 or more, 9,000 or more, 10,000 or more, 20,000 or more, 30,000 or more, 40,000 or more, 50,000 or more, 60,000 or more, 70,000 or more, 80,000 or more, 90,000 or more, or 100,000 or more. The molecular weight of the first segment and the molecular weight of the protein structure contained in the first segment may be 400,000 or less, 360,000 or less, 300,000 or less, or 200,000 or less.

[0098] The smaller the molecular weight of the first segment and the protein structure, the higher their solubility in a solvent tends to be. Therefore, when the molecular weight of the protein structure and / or the first segment is, for example, 200,000 or less or 100,000 or less, improving the efficiency of producing a polymer compound containing a target protein structure is desirable when obtaining a polymer compound containing a protein structure by dissolving a compound containing a protein structure in a solvent and reacting it with a compound containing a molecular group that has a plasticizing function for the protein structure. A laminate molded using the polymer compound containing a protein structure obtained in this manner can be expected to have improved flexibility while maintaining a certain level of strength. When the molecular weight of the protein structure and / or the first segment is, for example, 200,000 or less or 100,000 or less, it is expected that the amount of the second segment used can be minimized to increase the flexibility of the polymer compound containing a protein structure. The molecular weights of the first segment and the protein structure described above are weight-average molecular weights.

[0099] The molecular weights referred to herein are values ​​measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Such electrophoresis is performed as follows: First, 200 μL of 2 M lithium chloride DMSO (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) is added to 2 mg of powder sample, and the sample is dissolved by stirring at 80°C for 60 minutes and then at 95°C for 10 minutes. The sample is then diluted 50-fold with 10 M (mol / L) urea solution, further diluted 2-fold with sample buffer (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and heated at 95°C for 5 minutes to denature the protein. Next, an SDS-PAGE gel (manufactured by Bio-lad) is attached to an electrophoresis apparatus (manufactured by Bio-lad), the apparatus is filled with SDS buffer, and the electrophoresis apparatus is connected to a power supply (manufactured by Biocraft). Ten microliters of the denatured sample was added to each well of an SDS-PAGE gel, and a current of 30 mA was applied for 30 minutes. After electrophoresis, the SDS-PAGE gel was removed from the apparatus, immersed in Oriole fluorescent gel stain (Bio-lad), and shaken for 1 hour. The gel was then placed on a UV sample tray (Bio-lad), and a stained image was captured using a Gel Doc EZ gel imager (Bio-lad).

[0100] The number of amino acid residues constituting the protein structure may be 50 or more. The number of amino acid residues may be, for example, 100 or more, 150 or more, 200 or more, 250 or more, 300 or more, 350 or more, 400 or more, 450 or more, or 500 or more. The number of amino acid residues may be, for example, 5000 or less, 4500 or less, 4000 or less, 3500 or less, 3000 or less, 2500 or less, 2000 or less, 1500 or less, or 1000 or less. The fewer the number of amino acid residues, the higher the solubility in a solvent tends to be. Therefore, when the number of amino acid residues of the protein structure according to this embodiment is, for example, 5000 or less or 2500 or less, when a compound containing a protein structure is dissolved in a solvent and reacted with a compound containing a molecular group having a plasticizing function for the protein structure to obtain a polymer compound containing a protein structure, it may be desirable to improve the efficiency of producing a polymer compound containing a target protein structure. A laminate made using the polymer compound containing a protein structure obtained in this way can be expected to have improved flexibility while maintaining a certain level of strength.

[0101] The protein structure is a recombinant protein structure or a hydrophobic protein structure, and may be a hydrophobic recombinant protein structure.

[0102] A recombinant protein structure refers to a protein structure produced using genetic recombination technology. When the protein structure is a recombinant protein structure, the amino acid sequence can be easily modified, making it easy to control the characteristics and physical properties of polymer compounds containing the protein structure. When the protein structure is a recombinant protein structure, uniform molecular design is always possible, making it possible to stably obtain protein structures tailored to the intended purpose. This advantageously stabilizes the quality of polymer compounds and laminates containing the desired protein structure.

[0103] When the protein structure is a hydrophobic protein structure, the affinity of the molecular group having a plasticizing function with the first segment is improved, allowing the production of a laminate with greater flexibility. In addition, the water resistance of such a laminate is improved, which can advantageously extend the service life, for example, when the laminate is used as a general-purpose industrial material. The hydrophobicity or hydrophilicity of the entire polymer compound containing a protein structure can be adjusted as desired, for example, by controlling the hydrophobicity or hydrophilicity of the molecular group having a plasticizing function for the protein structure, which is contained in the second segment. When the protein structure is a hydrophobic protein structure, the entire polymer compound containing the protein structure can be shifted to the hydrophobic side compared to when the protein structure is a hydrophilic protein structure, thereby making it possible to control the hydrophobicity or hydrophilicity of the entire polymer compound containing the protein structure over a wider range.

[0104] The hydrophobicity of a hydrophobic protein structure can be estimated using the value of the average hydropathy index (degree of hydrophobicity: hydrophobicity index) described below as an index. The value of the average hydropathy index of a hydrophobic protein structure may be, for example, 0.00 or more, 0.10 or more, 0.20 or more, 0.22 or more, 0.25 or more, 0.30 or more, 0.35 or more, 0.40 or more, 0.45 or more, 0.50 or more, 0.55 or more, 0.60 or more, 0.65 or more, or 0.70 or more. The upper limit is not particularly limited, but may be, for example, 1.00 or less or 0.70 or less.

[0105] The hydrophobic protein structure preferably has low solubility in an aqueous lithium bromide solution (concentration: 9 M) at 60°C. This solubility can be evaluated using a protein structure obtained by decomposing a compound (protein structure) corresponding to the hydrophobic protein structure or a polymer compound containing the protein structure and isolating only the hydrophobic protein structure. The maximum concentration of the protein structure when dissolved in an aqueous lithium bromide solution (concentration: 9 M) at 60°C may be, for example, less than 30% by mass, less than 25% by mass, less than 20% by mass, less than 15% by mass, less than 10% by mass, less than 5% by mass, or less than 1% by mass. The hydrophobic protein structure may also be completely insoluble in an aqueous lithium bromide solution (concentration: 9 M) at 60°C.

[0106] The hydrophobic protein structure preferably has a large water contact angle. The water contact angle can be evaluated by forming a film on a substrate, the film being composed of a protein structure obtained by decomposing a compound (protein structure) corresponding to the hydrophobic protein structure or a polymer compound containing the protein structure and isolating only the hydrophobic protein structure, and using the film. A protein structure that constitutes a film that has a contact angle of 55° or more after 5 seconds of water being dropped onto the film is preferred as the hydrophobic protein structure. The contact angle may be, for example, 60° or more, 65° or more, or 70° or more.

[0107] The hydrophobic protein structure preferably has excellent hot water resistance. Hot water resistance can be evaluated using a protein structure obtained by decomposing a compound (protein structure) corresponding to the hydrophobic protein structure or a polymer compound containing the protein structure and isolating only the hydrophobic protein structure. A preferred hydrophobic protein structure is a protein that does not decompose even when a dispersion containing the protein structure and water is prepared, the dispersion containing the protein structure at 5% by mass, and is heated at 100°C for 5 hours.

[0108] Other preferred embodiments of the protein structure in the protein derivative are the same as the preferred embodiments of the protein described above.

[0109] [Second Segment] The second segment preferably includes a molecular group having a plasticizing function for the protein structure. The molecular group having a plasticizing function for the protein structure refers to a molecular group in which the intermolecular force between the molecular groups is weaker than the intermolecular force between the protein structures, and when the two are mixed, the flexibility of the material can be improved compared to the protein structure alone. The molecular group having a plasticizing function for the protein structure can also be a molecular group having a lower melting point or glass transition temperature than the protein structure. The molecular group having a plasticizing function for the protein structure may be, for example, a polyether, polyester, or polycarbonate. The polyether as the molecular group may be, for example, polyethylene glycol (PEG) or polytetramethylene glycol (PTMG). The plasticizing function can also be referred to as a function of improving flexibility or a function of increasing breaking elongation in bending and / or tension. The molecular group having a plasticizing function for the protein structure is preferably biodegradable or derived from biomass. This is expected to further increase the biodegradability and biovalue of the laminate as a whole, and further reduce the energy required to produce the laminate.

[0110] The second segment may contain a plurality of the molecular groups. The second segment may contain a plurality of the molecular groups, and the plurality of molecular groups may be connected to each other. The connections between the molecular groups may be partially branched. By partially branching the connections, the second segment can have a branched structure consisting of the plurality of molecular groups, and each branch can form multiple bonds with the first segment. That is, by introducing a branch into some of the connections, a network structure between the first segment and the second segment can be formed. In this way, when the second segment contains a plurality of the molecular groups and these molecular groups are connected to each other, the design options for the second segment can be broadened, and, for example, the flexibility of the laminate can be more easily adjusted. When the second segment contains only one of the molecular groups, multiple second segments may be connected to each other, and at least one of the multiple second segments may be bonded to the first segment. Alternatively, multiple second segments may be bonded to one first segment. When multiple second segments are connected to each other, a branch may be introduced into some of the connections between the multiple second segments to form a network of second segments.

[0111] The second segment may include, for example, a skeleton derived from at least one selected from the group consisting of polyether, polyester, polycarbonate, polyamide, polyol (such as polyvinyl alcohol), polyolefin, polyacetal, polyketal, poly(meth)acrylate, silicone, polyurethane, polyalkyleneimine, phenol resin, urea resin, melamine resin, and polysaccharide, and may preferably include at least one functional group selected from the group consisting of a polyether group, a polyester group, a polycarbonate group, a polyamide group, a polyol group (such as a polyvinyl alcohol group), and a modified polysaccharide group, or may include at least one functional group selected from the group consisting of an ether group, an ester group, a carbonate group, an amide group, and a modified polysaccharide group. The second segment may include, for example, at least one structural unit selected from the group consisting of structural units having an ether bond, an ester bond, a carbonate ester bond (carbonate bond), an amide group, a siloxane bond, a urethane bond, or a urea bond, and can also be said to include at least one structural unit selected from the group consisting of structural units having an alkylene group, a substituted alkylene group, an oxymethylene group, an alkyleneimine group, or a modified polysaccharide group.

[0112] Examples of polyether groups include functional groups derived from polyalkylene glycols such as polyethylene glycol, polypropylene glycol, ethylene oxide / propylene oxide copolymer, and polybutylene glycol (polytetramethylene glycol (PTMG)). When these polyether groups are contained in the second segment, the polyether group may be directly bonded to a heteroatom (O, N, S) in an ester group, thioester group, or amide group of a linker (described below) contained in the second segment, if necessary. Alternatively, the polyether group may be directly bonded to a heteroatom (O, N, S) in an ester group, thioester group, or amide group of a protein structure contained in the first segment. In this case, the entire polyether group is more likely to separate from the linker and / or the first segment, thereby increasing the biodegradation rate of the polyether group.

[0113] Examples of the polyester group include functional groups derived from polyesters such as polylactic acid, poly(3-hydroxybutanoic acid), polyhydroxybutanoic acid / hydroxyvaleric acid copolymer, polyhydroxybutanoic acid / 4-hydroxybutanoic acid copolymer, polyhydroxybutanoic acid / hydroxyhexanoic acid copolymer, polytrimethylene terephthalate, butanediol / long-chain dicarboxylic acid copolymer, polyethylene terephthalate, polybutylene succinate, polybutylene succinate-adipate copolymer, polybutylene adipate-terephthalate copolymer, polycaprolactone, and polytrimethylene furandicarboxylate (PTF). Of the above polyesters, the polyester group is preferably a functional group derived from a material classified as a biomass plastic or biodegradable plastic, such as polycaprolactone.

[0114] Examples of the polycarbonate group include functional groups derived from polycarbonates having an aliphatic hydrocarbon chain as the main skeleton, such as 1,6-hexanediol polycarbonate, 1,5-pentanediol polycarbonate, and 1,10-decanediol carbonate.

[0115] Examples of the polyamide group include functional groups derived from polyamides such as nylon 3, nylon 4, nylon 5, nylon 6, nylon 11, and nylon 610. Of the above-mentioned polyamides, the polyamide group is preferably a functional group derived from a polyamide classified as a biomass plastic or a biodegradable plastic.

[0116] Examples of the polyol group (such as a polyvinyl alcohol group) include functional groups derived from polyols (such as polyvinyl alcohols) such as polyvinyl alcohol and ethylene-vinyl alcohol copolymers. Of the above-mentioned polyols, the polyol group is preferably a functional group derived from a polyol classified as a biomass plastic or a biodegradable plastic.

[0117] The modified polysaccharide group may be, for example, a functional group derived from a compound obtained by chemically modifying cellulose, starch, chitin, chitosan, etc. Examples of the chemically modified compound include cellulose acetate, ethyl cellulose, starch acetate, hydroxypropylated starch, carboxymethyl chitin, and carboxymethyl chitosan.

[0118] The second segment may further include a linker in addition to the molecular group having a plasticizing function for the protein structure. In this case, the molecular group and the protein structure may be bonded via the linker. Examples of the linker include a group formed by bonding an electrophilic functional group represented by any of the formulas (1) to (20) described below with a nucleophilic functional group contained in Compound A described below.

[0119] The molecular weight of the second segment (a molecular group having a plasticizing function on the protein structure) may be, for example, 200 to 500,000, 300 to 400,000, 350 to 350,000, 400 to 300,000, 500 to 200,000, 600 to 100,000, 700 to 50,000, 800 to 10,000, 900 to 7,500, or 1,000 to 5,000.

[0120] When the molecular weight of the second segment is 200 or more, localization of the molecular group having a plasticizing function within the three-dimensional structure of the molecule is easily suppressed, and the mass ratio of the molecular group having a plasticizing function that must be introduced to exert a certain level of function can be sufficiently reduced. As a result, it may be possible to shorten the reaction time and lower the reaction temperature in the production of a polymer compound containing a protein structure.

[0121] When the molecular weight of the second segment is 500,000 or less, the molecular weight falls within an appropriate range, and a decrease in the binding reactivity of the second segment with the first segment is more easily suppressed.

[0122] The molecular weight of the second segment is a weight average molecular weight, which is generally determined by a known method using GPC.

[0123] The molecular weight of the second segment (a molecular group having a plasticizing function for the protein structure) relative to the molecular weight of the first segment (protein structure) can be adjusted appropriately depending on the application of the polymer compound containing the protein structure, etc. The molecular weight of the second segment (the total molecular weight when two or more second segments are bound to one first segment) is, for example, preferably 1 to 10,000, more preferably 1.5 to 9,000, even more preferably 2 to 8,000, still more preferably 3 to 7,000, even more preferably 5 to 5,000, still more preferably 7 to 3,000, and even more preferably 10 to 2,000, based on the molecular weight of the first segment (100).

[0124] When the ratio of the molecular weight of the second segment to the molecular weight of the first segment is 1 or more, the flexibility of the laminate obtained using the polymer compound containing a protein structure can be further increased. When the ratio of the molecular weight of the second segment to the molecular weight of the first segment is 10,000 or less, the laminate has sufficient plasticity (flexibility) and the rigidity of the laminate material can be further improved. When the ratio of the molecular weight of the second segment to the molecular weight of the first segment is within the above range, it is possible to produce a laminate with excellent flexibility.

[0125] The molecular weight of the second segment and the molecular weight of the molecular group having a plasticizing function for the protein structure may be, for example, 1.4 or more, 1.5 or more, 1.6 or more, 1.7 or more, 1.8 or more, 1.9 or more, 2.0 or more, 5.0 or more, 10 or more, 20 or more, 30 or more, or 40 or more, when the molecular weight of the first segment or the molecular weight of the protein structure contained in the first segment is taken as 100 (preferably when the molecular weight of the protein structure contained in the first segment is taken as 100). The upper limit is not particularly limited, and may be, for example, 1000 or less, 800 or less, 600 or less, 400 or less, 200 or less, 100 or less, 80 or less, 70 or less, 60 or less, or 50 or less. The molecular weight of the second segment is preferably in the range of 1 to 1,000, more preferably in the range of 1 to 800, even more preferably in the range of 1 to 600, even more preferably in the range of 1 to 400, and even more preferably in the range of 1 to 200, when the molecular weight of the first segment is taken as 100. When the ratio of the molecular weight of the first segment (protein structure) to the molecular weight of the second segment (molecular group having a plasticizing function for the protein structure) is a value within the above range, for example, in a laminate obtained using a polymer compound containing a protein structure, it can be expected that the properties of the first segment due to the presence of the protein structure (e.g., high mechanical strength) will be sufficiently maintained while improving flexibility, extensibility, etc. The ratio of the molecular weight of the second segment to the molecular weight of the first segment taken as 100 is determined in terms of weight average molecular weight.

[0126] The content ratio of the first segment (protein structure) to the second segment (molecular group having plasticizing function) in the polymer compound containing a protein structure can be adjusted appropriately depending on the application of the laminate, etc. Such a content ratio, in mass ratio, when the second segment is taken as 100, may be, for example, 50 or more, 60 or more, 70 or more, 80 or more, 90 or more, 100 or more, 110 or more, 150 or more, 200 or more, 250 or more, 300 or more, 350 or more, 400 or more, 450 or more, 500 or more, 550 or more, or 600 or more of the first segment. The upper limit of this value is not particularly limited, but may be 1000 or less, 900 or less, 800 or less, or 700 or less. By setting the content ratio of the first segment to the second segment in the polymer compound containing a protein structure to a value within the above range, wasteful use of the second segment can be suppressed, and the production cost of the polymer compound containing a protein structure can be reduced. In a polymer compound containing a protein structure, the content ratio of the second segment to the first segment can be advantageously reduced by, for example, reducing the molecular weight of the second segment.

[0127] In the above description of the embodiment, the linker has been described as a component of the second segment, but it may be treated separately from the second segment. The linker can also be treated as a component of the first segment. Although the molecular weight of the linker portion is smaller than the above protein structure and the above molecular group, when the linker is treated separately from the second segment, the range obtained by subtracting the molecular weight of the linker portion from the molecular weight of the second segment is treated as the preferred molecular weight range of the second segment. Similarly, when the linker portion is treated as a component of the first segment, the range obtained by adding the molecular weight of the linker portion to the molecular weight of the first segment is treated as the preferred molecular weight range of the first segment.

[0128] [Method for Producing Block Copolymer] - First Aspect of Method for Producing Block Copolymer - The block copolymer in the polymer compound containing a protein structure is preferably obtained by a production method including a step of mechanochemically treating a mixture containing a compound having a protein structure (hereinafter also referred to as "compound A") and a compound having a molecular group capable of plasticizing the protein structure (hereinafter also referred to as "compound B"). The first segment described above is formed by compound A, and the second segment described above is formed by compound B. In other words, the block copolymer contained in the polymer compound containing a protein structure is preferably obtained by mechanochemically treating a mixture containing the compound having the protein structure and a compound having a molecular group capable of plasticizing the protein structure.

[0129] Preferred aspects of the protein structure in compound A are as described above. Compound A is preferably a protein. The definition of protein used in the method according to this embodiment can be taken into consideration as defined above. The protein preferably includes a hydrophobic protein. Furthermore, the hydrophobic protein preferably has a hydropathic index greater than 0. The protein may be an artificial protein, and preferably includes an artificially structured protein.

[0130] In certain embodiments, for example, compound A has two or more nucleophilic functional groups and compound B has two or more electrophilic functional groups. In this embodiment, the nucleophilic functional groups and the electrophilic functional groups are bonded to each other to form a block copolymer comprising compound A and compound B as monomer units. In a preferred embodiment, compound A has two or more hydroxyl, amino, or thiol groups, and compound B has two or more hydroxy-, amine-, or thiol-reactive groups.

[0131] The electrophilic functional group is, for example, a group represented by any one of formulas (1) to (20), and preferred electrophilic functional groups are groups represented by formulas (1), (2), (6) to (8), (16), or (19), and more preferred electrophilic functional groups are groups represented by formulas (1), (2), or (6). Preferred combinations of nucleophilic functional groups and electrophilic functional groups include a hydroxyl group and a hydroxy-reactive group represented by any one of formulas (2) to (9), (13) to (17), and (19), an amino group and an amine-reactive group represented by any one of formulas (2) to (9), (13) to (17), and (19), and a thiol group and a thiol-reactive group represented by any one of formulas (1) to (6), (8), (10) to (15), and (18).

[0132] In formulas (1) to (20), R ２ In formulae (2) to (8) and (13) to (15), Y represents, independently of each other, an oxygen atom, a sulfur atom, or NR １ indicates R １ represents a hydrogen atom, a hydrocarbon group, an aromatic group, a carbonyl group, or a sulfonyl group. In formulas (2) to (6) and (10) to (15), R each independently represents a hydrogen atom, a hydrocarbon group, or an aromatic group. In formulas (8) and (16), Z represents a halogen atom, a sulfonate ester group, or a fluorine-containing carboxylate ester group. In formula (19), X represents a halogen atom.

[0133] The amount of compound B used may be 1.5 to 7 equivalents per nucleophilic functional group contained in compound A. The amount of compound B used may preferably be 1.5 to 6.5 equivalents, 1.5 to 6 equivalents, 1.5 to 5.5 equivalents, 1.5 to 5 equivalents, 1.5 to 4 equivalents, 2 to 7 equivalents, 2 to 6.5 equivalents, 2 to 6 equivalents, 2 to 5.5 equivalents, 2 to 5 equivalents, 2 to 4.5 equivalents, 2.5 to 7 equivalents, 2.5 to 6.5 equivalents, 2.5 to 6 equivalents, 2.5 to 5.5 equivalents, 2.5 to 5 equivalents, or 2.5 to 4.5 equivalents per nucleophilic functional group. "Equivalent per nucleophilic functional group" means the molar equivalent of compound B per nucleophilic functional group contained in compound A. By setting the amount of compound B used to a value within the above range, the reactivity or reaction efficiency between compound A and compound B in the mechanochemical treatment is enhanced, and the target block copolymer can be obtained more efficiently.

[0134] Mechanochemical processing is a process in which a chemical reaction is induced by the direct absorption of mechanical energy. Such mechanical energy may be exerted, for example, by impact force or shear force. Specifically, such mechanochemical processing is carried out using a tumbling ball mill, a media-agitated mill, a planetary mill, a jet mill, a mixer mill, an extruder (twin-screw extruder), or the like. Specifically, compound A and compound B are placed in a grinding jar, and media balls, etc., are added depending on the type of mill used. The grinding jar is then placed in a mixer mill device and vibrated at a predetermined frequency and reaction time. At this time, a solvent, a base, a reaction accelerator, etc. may be further added to the grinding jar. Alternatively, compound A and compound B are placed in a mixer mill, and the milling procedure is initiated, followed by continuous kneading of the reactants. At this time, a solvent, a base, a reaction accelerator, etc. may be further added to the mixer mill. Alternatively, compound A and compound B are placed in an extruder and kneaded. At this time, a solvent, a base, a reaction accelerator, etc. may be further added to the extruder. Furthermore, if mechanochemical treatment is carried out using an extruder, it becomes possible to continuously produce the desired block copolymer.

[0135] The frequency can be adjusted appropriately by those skilled in the art depending on the reaction, and may be, for example, 10 to 50 Hz, 10 to 45 Hz, 10 to 40 Hz, 10 to 35 Hz, 15 to 50 Hz, 15 to 45 Hz, 15 to 40 Hz, 15 to 35 Hz, 20 to 50 Hz, 20 to 45 Hz, 20 to 40 Hz, or 20 to 35 Hz.

[0136] The reaction time can be set to the point where the raw material compound A disappears or a certain level of the block copolymer is detected by infrared (IR) absorption spectroscopy, gel filtration chromatography (GPC), etc. The reaction time may be any time, for example, 30 to 240 minutes, 30 to 210 minutes, 30 to 180 minutes, 30 to 150 minutes, 30 to 120 minutes, 30 to 110 minutes, 30 to 100 minutes, 30 to 95 minutes, 60 to 240 minutes, 60 to 210 minutes, 60 to 180 minutes, 60 to 150 minutes, 60 to 120 minutes, 60 to 110 minutes, 60 to 100 minutes, 6 ... The time may be up to 95 minutes, 70 to 240 minutes, 70 to 210 minutes, 70 to 180 minutes, 70 to 150 minutes, minutes, 70 to 120 minutes, 70 to 110 minutes, 70 to 100 minutes, 70 to 95 minutes, 80 to 240 minutes, 80 to 210 minutes, 80 to 180 minutes, 80 to 150 minutes, minutes, 80 to 120 minutes, 80 to 110 minutes, 80 to 100 minutes, or 80 to 95 minutes.

[0137] The solvent may be any solvent capable of swelling compound A or capable of dissolving at least one of compound A and compound B. However, it must be a compound that is liquid at room temperature and normal pressure and does not chemically react with compound A. Mechanochemical treatment using such a solvent is known as liquid-assisted grinding (LAG), and is a method in which the desired reaction proceeds more efficiently by adding a small amount of solvent to a grinding jar. Examples of such solvents include alcoholic solvents such as methanol and ethanol, and aprotic polar solvents such as dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpiperidone (NMP), and dihydrolevoglucosenone. The amount of solvent used may be, for example, 0.01 g to 1 g, or may be 0.01 g to 0.8 g, 0.01 g to 0.6 g, 0.01 g to 0.4 g, or 0.01 g to 0.2 g per 1 g of compound A. In other words, the amount of solvent used may be, for example, 1 to 100% by mass, or may be 1 to 80% by mass, 1 to 60% by mass, 1 to 40% by mass, or 1 to 20% by mass, relative to compound A. It is believed that a trace amount of solvent forms a microscopic reaction field by swelling compound A or locally dissolving compound A. Note that the addition of a solvent is not always necessary; for example, when compound B is a liquid at room temperature and normal pressure and has the above-mentioned function as a solvent, the addition of a solvent may not be necessary.

[0138] When obtaining a protein in which at least some or all of the lysine, serine, threonine, tyrosine, or cysteine ​​residues in the protein are acylated, the base may be any base that can assist in the acylation of the hydroxyl groups of serine, threonine, or tyrosine residues, the amino groups of lysine residues, and the sulfhydryl groups of cysteine ​​residues in the protein. Examples of the base include tertiary amines, nitrogen-containing aromatic compounds, and inorganic bases, and more specific examples include triethylamine, DIPEA (N,N-diisopropylethylamine), DABCO (1,4-diazabicyclo[2.2.2]octane), quinuclidine, DBU (1,8-diazabicyclo[5.4.0]undec-7-ene), DBN (1,5-diazabicyclo[4.3.0]non-5-ene), pyridine, imidazole, sodium hydroxide, potassium hydroxide, sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate, cesium carbonate, tripotassium phosphate, sodium acetate, and potassium acetate. The amount of the base used may be, for example, 1 to 10, 1 to 8, 1 to 7, 1 to 6, or 1 to 5, when the amount of nucleophilic functional groups contained in the protein is taken as 1. The amount of the base varies depending on the type of base used, and the like. For example, when sodium hydroxide is used as the base, the amount of the base is preferably 1 to 5, more preferably 1 to 2, and when DIPEA is used as the base, the amount of the base is preferably 1 to 5, more preferably 3.5 to 5.

[0139] The reaction promoter may be any one known in the field of organic chemistry to promote acylation reactions, such as 4-dimethylaminopyridine (DMAP). When the acylation is acetylation, no reaction promoter is required.

[0140] When the acylation is succinylation, the rate of the acylation reaction can be increased by adding a reaction promoter. In this case, the amount of the reaction promoter used may be more than 0 equivalents but not more than 5 equivalents, preferably 3.5 to 5 equivalents, per mole of the nucleophilic functional group contained in the protein (one amino acid residue having a nucleophilic functional group). The amount of the reaction promoter used may be more than 0 moles but not more than 1 mole, preferably 0.3 moles to 1 mole, per mole of the base used.

[0141] When the acylation is stearylation, the rate of the acylation reaction can be increased by adding a reaction accelerator. In this case, the amount of the reaction accelerator used may be 1 to 5 equivalents, preferably 3.5 to 5 equivalents, per mole of the nucleophilic functional group contained in the protein (one amino acid residue having a nucleophilic functional group). The amount of the reaction accelerator used may be 0.2 to 1 mole, or may be 0.7 to 1 mole, per mole of the base used.

[0142] After the reaction is complete, the mixture may be removed from the grinding jar and washed with a solvent. Washing can remove unreacted substances and excess by-products produced by the reaction. Examples of solvents used for washing include water, methanol, ethanol, acetonitrile, acetone, tetrahydrofuran, ethyl acetate, and hexane. After washing, the product may be dried to distill off the solvent used for washing. Drying may be performed under reduced pressure.

[0143] The average particle size of the block copolymer according to this embodiment is preferably 1 to 80 μm, 1 to 50 μm, 2 to 50 μm, 2 to 40 μm, 4 to 25 μm, 5 to 25 μm, 8 to 25 μm, or 8 to 16 μm. An average particle size within the above range provides excellent handleability. The average particle size can be determined, for example, by the following method. Particles or powder of the block copolymer are uniformly dispersed on a glass plate by suction in a vacuum chamber, and then measured five times each using a wet / dry image analysis particle size distribution meter (product name: DW-200 nano, manufactured by Jasco International Inc.). Projected images are then captured using a 10-megapixel camera, and the resulting projected images are analyzed using image analysis software.

[0144] The block copolymer according to this embodiment is obtained as a powder with a smaller average particle size and a more uniform particle size by mechanochemically treating a mixture containing compound A and compound B and then freeze-drying it. The average particle size of the block copolymer powder obtained by freeze-drying is, for example, about 1 to 30 μm, 1 to 20 μm, 1 to 10 μm, or 2 to 8 μm. Such powdered block copolymers are easier to handle and allow for fine adjustment of the amount used. Moreover, the freeze-dried block copolymer not only has a small average particle size, but also is expected to loosen the tertiary structure of compound A, thereby improving its dispersibility in aqueous media (aqueous liquids) such as water, basic aqueous solutions, acidic aqueous solutions, and neutral aqueous solutions containing inorganic salts, as well as its solubility in solvents. In particular, when the block copolymer powder obtained by mechanochemical treatment or an aqueous dispersion obtained by dispersing the block copolymer powder obtained by further freeze-drying it in an aqueous medium is applied to a substrate surface, it can be applied more uniformly and without unevenness. This allows for the formation of a more uniform coating film with as little unevenness as possible. That is, the aqueous dispersion of the block copolymer powder can also be useful as a coating liquid for forming a coating film. Furthermore, the aqueous dispersion of the block copolymer powder can be applied to the surface of a substrate, followed by laminating another substrate thereon, and then curing the block copolymer to bond the two substrates. In other words, the aqueous dispersion of the block copolymer according to this embodiment can also be useful as a water-dispersible adhesive. When the aqueous dispersion of the block copolymer is used as a coating liquid, for example, a predetermined colorant or an additive commonly used in coating liquids or the like may be added, blended, or mixed with the aqueous dispersion of the block copolymer. When the aqueous dispersion of the block copolymer is used as a water-dispersible adhesive, an additive commonly used in adhesives or the like may be added, blended, or mixed with the aqueous dispersion of the block copolymer. Since the coating liquid and water-dispersible adhesive made from the aqueous dispersion of the block copolymer according to this embodiment use an aqueous medium such as water as a solvent, they are suitable for application to or adhesion of materials with low organic solvent resistance, and the odor characteristic of organic solvents can also be reduced.

[0145] Block copolymers produced by mechanochemical methods use no organic solvents or only a very small amount of organic solvent (an amount sufficient to swell molecules capable of plasticizing compound A or compound B) in the production process, so that organic solvents are less likely to remain and the copolymers can be easily purified into powders.

[0146] The block copolymer powder thus obtained, or a powder obtained by pulverizing the block copolymer by a known method as needed, can be dissolved in a solvent and used to form a solution layer for forming a surface layer in the method for producing a laminate of this embodiment.

[0147] - Second Aspect of Method for Producing Block Copolymer - Furthermore, a block copolymer in a polymer compound containing a protein structure is also preferably produced by a method comprising reacting, by heating, in an organic solvent, a protein having at least one mercapto group (hereinafter also referred to as "compound C") and a compound having at least one structure selected from the group consisting of polyethers, polyesters, and polycarbonates, the compound having two structures represented by the following formula (M-1) or formula (M-2) (hereinafter also referred to as "compound D"). In formula (M-1), M is H, Na, K, or NHEt ３ , or NHEtiPr ２ In this specification, Et represents an ethyl group, and iPr represents an isopropyl group. １ represents a hydrogen atom or a methyl group.

[0148] The compound C forms the first segment, and the compound D forms the second segment.

[0149] <<Compound C>> Compound C is preferably a compound containing the above-described first segment. Here, the mercapto group in Compound C is preferably a mercapto group contained in a cysteine ​​residue in a protein structure. Other preferred aspects of the first segment in Compound C are as described above.

[0150] In the above production method, the blending amount of the compound C may be, for example, more than 1 part by mass, 2 parts by mass or more, 5 parts by mass or more, more than 5 parts by mass, 6 parts by mass or more, 7 parts by mass or more, or 8 parts by mass or more, relative to 100 parts by mass of the organic solvent. In the production method according to the present disclosure, the blending amount of the compound C may be, for example, 50 parts by mass or less, 30 parts by mass or less, 20 parts by mass or less, or 15 parts by mass or less, relative to 100 parts by mass of dimethyl sulfoxide. When the upper limit of the blending amount of the compound C is within the above range, the reaction can proceed while more sufficiently suppressing the generation of by-products and gelation.

[0151] <<Compound D>> Preferred embodiments of the polyether, polyester, and polycarbonate in Compound D are the same as those preferred embodiments in the second segment described above.

[0152] In the above production method, the ratio of the number of moles of the structure represented by formula (M-1) or formula (M-2) in compound D to the number of moles of mercapto groups in compound C may be, for example, 0.1 times or more, 0.2 times or more, 0.5 times or more, or 0.7 times or more. By setting this ratio within the above range, the reaction can proceed while further suppressing a decrease in reactivity. Furthermore, in the above production method, the ratio of the number of moles may be, for example, 5.0 times or less, 3.0 times or less, 1.5 times or less, or 0.8 times or less. By setting this ratio within the above range, the reaction can proceed while further suppressing the generation of by-products and gelation. By adjusting the above molar ratio, the number of polyether structures, etc. in the obtained polymer compound can be adjusted.

[0153] <<Organic Solvent>> The organic solvent is not particularly limited as long as it can dissolve Compound C and Compound D, but dimethyl sulfoxide is preferred.

[0154] <<Base>> Here, during the heating reaction, it is preferable to further contain a base in addition to Compound C and Compound D. By containing a base, the mercapto group in Compound C can be activated, and the Michael addition reaction between the functional group represented by Formula (M-1) and the mercapto group can be promoted. Examples of the base include primary amines, secondary amines, tertiary amines, nitrogen-containing ring compounds, nitrogen-containing aromatic compounds, and inorganic bases. Examples of primary amines include ethanolamine and hexamethylenediamine. Examples of secondary amines include diethylamine, methylethylamine, and N-methylbutylamine. Examples of tertiary amines include triethylamine, diethylmethylamine, and DIPEA (N,N-diisopropylethylamine). Examples of nitrogen-containing ring compounds include quinuclidine, DABCO (1,4-diazabicyclo[2.2.2]octane), DBU (1,8-diazabicyclo[5.4.0]undec-7-ene), and DBN (1,5-diazabicyclo[4.3.0]non-5-ene). Examples of nitrogen-containing aromatic compounds include pyridine and imidazole. Examples of inorganic bases include sodium hydroxide, potassium hydroxide, sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate, cesium carbonate, tripotassium phosphate, sodium acetate, and potassium acetate.

[0155] The lower limit of the amount of the base may be, for example, 0.01 parts by mass or more, 0.05 parts by mass or more, 0.1 parts by mass or more, or 0.5 parts by mass or more, based on the mass of compound C. By setting the lower limit of the amount of the base within the above range, the reaction between the mercapto group of compound C and the unsaturated bond represented by formula (M-1) or general formula (M-2) of compound D can be further promoted. The upper limit of the amount of the base may be, for example, 50 parts by mass or less, 20 parts by mass or less, 10 parts by mass or less, or 5 parts by mass or less, based on the mass of the protein. By setting the upper limit of the amount of the base within the above range, molecular decomposition due to the influence of residual base can be further suppressed, allowing the synthesis of the desired polymer compound. The amount of the base may be adjusted within the above range, and may be, for example, 0.05 to 50 parts by mass or 0.1 to 10 parts by mass, based on the mass of the protein.

[0156] <<Reducing Agent>> Here, during the heating reaction, it is also preferable to further contain a reducing agent in addition to Compound C and Compound D. The reducing agent itself is stable in dimethyl sulfoxide, is unlikely to undergo a Michael addition reaction with the functional group represented by Formula (M-1) or Formula (M-2), and can inhibit the formation of disulfide bonds between mercapto groups in the protein. The reducing agent may, for example, include at least one selected from the group consisting of thiol, dithiol, sodium carbonate, sodium sulfite, sodium hyposulfite, sodium sulfate, and sodium dithionite. The reducing agent may include at least one selected from the group consisting of dithiol, sodium carbonate, and sodium sulfite, and may be dithiol or sodium sulfite. The reducing agent is preferably a compound having a mercapto group.

[0157] The compound having a mercapto group is preferably a compound represented by the following general formula (Y). Such a compound forms a chemically stable six-membered ring structure in its oxidized form after the reduction reaction, suppressing the reaction between the reducing agent and the Michael addition acceptor in the reaction system. Furthermore, by forming a ring structure between the reducing agent and the mercapto group of the protein, the formation of disulfide bonds between proteins is suppressed, making the reaction between the mercapto group of the protein and the Michael addition acceptor more significant, thereby enabling the production of a target polymer compound in line with the reaction design more efficiently. Examples of dithiols include dithiothreitol and 1,4-butanedithiol. The compound (dithiol) represented by general formula (Y) is specifically dithiothreitol or 1,4-butanedithiol.

[0158]

[0159] Other compounds having a mercapto group include, for example, 3-mercaptopropionic acid, 3-mercapto-1,2-propanediol, and pentaerythritol tetra(3-mercaptopropionate). In addition to the above compounds, the reducing agent may also be, for example, tris(2-carboxyethyl)phosphine (TCEP).

[0160] The lower limit of the amount of the reducing agent may be, for example, 0.5 equivalents or more, 0.8 equivalents or more, or 1.0 equivalents or more relative to the mercapto groups of compound C. By setting the lower limit of the amount of the reducing agent within the above range, the formation of disulfide bonds due to the reaction between the mercapto groups of compound C can be more sufficiently inhibited. This can further improve the production efficiency of the target synthetic polymer compound. The upper limit of the amount of the reducing agent may be, for example, 2.4 equivalents or less, 2.0 equivalents or less, 1.6 equivalents or less, 1.2 equivalents or less, or 1.1 equivalents or less relative to the mercapto groups of compound C. By setting the upper limit of the amount of the reducing agent within the above range, the reaction between compound D and the reducing agent and the generation of by-products can be further suppressed while the reaction proceeds.

[0161] <<Polymerization Inhibitor>> Here, during the heating reaction, it is also preferable to further contain a polymerization inhibitor in addition to compound C and compound D. The polymerization inhibitor is a compound that inhibits self-polymerization of compound D. Examples of the polymerization inhibitor include hydroquinone, methoquinone, 4-tert-butylpyrocatechol, tert-butylhydroquinone, 1,4-benzoquinone, dibutylhydroxytoluene, methoquinol, phenothiazine, and 1,1-diphenyl-2-picrylhydrazyl.

[0162] The content of the polymerization inhibitor may be, for example, 0.01 parts by mass or more, 0.05 parts by mass or more, 0.1 parts by mass or more, or 0.2 parts by mass or more, relative to 100 parts by mass of compound D. By setting the content of the polymerization inhibitor within the above range, for example, the initiation of radical polymerization of the structure represented by formula (M-2) is suppressed, and it may be possible to make the reaction between the structure represented by formula (M-2) and the mercapto group of compound C more dominant. The content of the polymerization inhibitor may be, for example, 25 parts by mass or less, 10 parts by mass or less, 5 parts by mass or less, or 1 part by mass or less, relative to 100 parts by mass of compound D. By setting the content of the polymerization inhibitor within the above range, it is possible to further suppress the polymerization inhibitor from inhibiting the reaction in the system.

[0163] When a compound having a structure represented by the above formula (M-1) is used as compound D, it is preferable to add a reducing agent during the heating reaction, and it is preferable to add a reducing agent and a base during the heating reaction. When a compound having a structure represented by the above formula (M-2) is used as compound D, it is preferable to add a polymerization inhibitor and a reducing agent during the heating reaction, and it is preferable to add a polymerization inhibitor, a reducing agent, and a base during the heating reaction.

[0164] <<Reaction Conditions>> In the above production method, the reaction temperature in the heating reaction may be, for example, 50°C or higher, 53°C or higher, 55°C or higher, 57°C or higher, or 60°C or higher. When the lower limit of the reaction temperature is within the above range, the reaction between compound C and compound D can be further promoted. In the above production method, the upper limit of the reaction temperature for the reaction between compound C and compound D may be, for example, 90°C or lower, 85°C or lower, 80°C or lower, 75°C or lower, or 70°C or lower. When the upper limit of the reaction temperature is within the above range, the formation of bonds between mercapto groups in proteins as a side reaction can be further suppressed, allowing the desired polymer compound to be synthesized efficiently. The reaction temperature for the reaction between compound C and compound D may be adjusted within the above range, and may be, for example, 50 to 90°C, 53 to 80°C, 55 to 75°C, or 55 to 70°C.

[0165] The timing of heating is not limited to after mixing of compounds C and D, and further components such as a base, a reducing agent, and a polymerization inhibitor that are added as needed. For example, these components may be added to a preheated organic solvent (e.g., dimethyl sulfoxide); necessary components out of the base, reducing agent, and polymerization inhibitor may be added to dimethyl sulfoxide, heating may be initiated, and after a predetermined temperature has been reached, compounds C and D may be added and reacted; or one of compounds C and D and necessary components out of the base, reducing agent, and polymerization inhibitor may be added, heating may be initiated, and after a predetermined temperature has been reached, the remaining one of compounds C and D may be added and reacted.

[0166] According to such a method, the block copolymer is obtained in the form of a solution dissolved in an organic solvent. The block copolymer is recovered from this solution by a known method such as drying, reprecipitation, or dialysis, and then pulverized as necessary to obtain a powder of a polymer compound containing a protein structure.

[0167] Alternatively, the block copolymer can be obtained by, for example, the method described in WO 2023 / 013638.

[0168] <Method for manufacturing second laminate> The method for manufacturing the second laminate is a method for manufacturing a laminate in which a foam layer and a skin layer are laminated on a fabric layer, and includes the steps of: causing a foam layer-forming solution, which contains a polymer compound having a protein structure, a solvent, and bubbles, to be present on the fabric layer to form a foam layer-forming solution layer on the fabric layer (also referred to as a "foam layer-forming solution layer manufacturing step"); causing the foam layer-forming solution layer to be gelled to form a foam layer precursor gel (also referred to as a "foam layer precursor gel forming step"); causing a skin layer-forming solution, which contains a polymer compound having a protein structure and a solvent, to be directly present on the foam layer precursor gel to form a skin layer-forming solution layer (also referred to as a "skin layer-forming solution layer manufacturing step"); and causing the skin layer-forming solution layer to be gelled to form a skin layer precursor gel (also referred to as a "skin layer precursor gel forming step"). The method includes a step of contacting the foam layer precursor gel and the skin layer precursor gel with a solvent displacement liquid to displace the solvent in the foam layer precursor gel and the skin layer precursor gel with the solvent displacement liquid (the "displacement step"); and a step of removing the solvent displacement liquid from the foam layer precursor gel and the skin layer precursor gel to solidify the foam layer precursor gel and the skin layer precursor gel, thereby laminating the foam layer and the skin layer on the fabric layer (also referred to as the "lamination step").

[0169] In the second laminate manufacturing method, the foam layer-forming solution layer manufacturing step can be performed in the same manner as the skin layer-forming solution layer manufacturing step in the first laminate manufacturing method, except that a foam layer-forming solution containing bubbles is used as the foam layer-forming solution. The preferred aspects of the steps are also the same. The foam layer precursor gel-forming step can be performed in the same manner as the skin layer precursor gel-forming step in the first laminate manufacturing method. The preferred aspects of the steps are also the same.

[0170] In the second method for producing a laminate, the step of producing a skin layer-forming solution layer can be performed in the same manner as the step of producing a skin layer-forming solution layer in the first method for producing a laminate, except that a skin layer-forming layer is formed on a foam layer precursor gel. Preferred aspects of the steps are also the same.

[0171] In the second method for producing a laminate, the laminate formation step can be performed in the same manner as the laminate formation step in the first method for producing a laminate, except that the foam layer precursor gel and the skin layer precursor gel are brought into contact with the solvent displacement liquid. Preferred aspects of the steps are also the same.

[0172] In the second method for producing a laminate, the substitution step can be performed in the same manner as the substitution step in the first method for producing a laminate, except that the foam layer precursor gel and the skin layer precursor gel are brought into contact with the solvent substitution liquid. Preferred aspects of the step are also the same.

[0173] <Applications> The laminate obtained by the laminate manufacturing method of this embodiment can be used for synthetic leather, electronic materials, etc., and is preferably used as synthetic leather. As synthetic leather, it can be used for, for example, the same applications as conventional synthetic leather (for example, synthetic leather made of synthetic resin). The synthetic leather of this embodiment can be used for, for example, clothing, decorative items such as shoes and bags, various covers and furniture, and automotive interior materials. As electronic materials, it can be used for, for example, flexible flat cables, flexible printed wiring boards, insulating films, cover films, reinforcing plates, support members for glass, silicon wafers, etc.

[0174] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, processing details, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[0175] (Example 1: Prototype of Synthetic Leather Without a Sponge Layer) 1) Preparation of Bubble-Free BCP (Block Copolymer) Solution 124.3 g of dimethyl sulfoxide (DMSO) was weighed into a three-neck flask, and 183 mg of dithiothreitol (DTT) was added as a reducing agent and stirred to dissolve. Next, 12.8 g of artificial fibroin (polypeptide, 10 kDa) having the amino acid sequence shown in SEQ ID NO: 9 (PRT3177) was added, and the mixture was heated and stirred at 85°C for 30 minutes to dissolve the mixture. 12.8 g of polyethylene glycol bismaleate (molecular weight 11,000) was then added, and the mixture was heated and stirred at 85°C for 30 minutes to obtain a DMSO solution containing a polymer compound in which a polypeptide moiety and a polyethylene glycol moiety were bonded. The stirring speed during the reaction was 300 rpm, and air bubbles were mixed into the solution. After the reaction was completed, the reaction vessel was depressurized using a diaphragm pump (PG201, manufactured by Yamato Scientific) to remove the air bubbles, thereby obtaining a degassed BCP solution (BCP solution A).

[0176] 2) Method for Manufacturing Synthetic Leather: A cotton knit fabric cut to a length of 30 cm and a width of 8 cm was impregnated with water in an amount equivalent to 180% of the weight of the cotton knit fabric and coated with approximately 50 g of the BCP solution A prepared as described above to a thickness of 2.5 mm, including the base fabric. After gelation for 60 minutes at 20°C and 65% rh (relative humidity), and after confirming that the coating solution had lost its fluidity, the fabric was immersed in 1 L of tap water at 60°C for 10 minutes to replace the solvent in the coating layer with water. In this state, the viscosity of the coating solution was 50,000 mPa·s or greater. This replacement process was repeated five times to remove the DMSO, and the fabric was then dried in an oven at 120°C for 60 minutes to obtain a soft synthetic leather with an average thickness of 0.81 mm and good surface texture.

[0177] (Example 2: Prototype of Synthetic Leather Without a Sponge Layer Using a Short Gelation Time) A cotton knit fabric cut to a length of 30 cm and a width of 8 cm was impregnated with water in an amount equivalent to 180% of the weight of the cotton knit fabric and coated with approximately 50 g of the BCP solution A prepared as described above to a thickness of 2.5 mm, including the base fabric. After gelation for 10 minutes at 20°C and 65% RH, and confirmation that the coating solution had lost its fluidity, the fabric was immersed in 1 L of tap water at 60°C for 10 minutes to replace the solvent in the coating layer with water. In this state, the viscosity of the coating solution was greater than 50,000 mPa·s. The above replacement process was repeated five times to remove the DMSO, and the fabric was then dried in an oven at 120°C for 60 minutes to obtain a soft synthetic leather with an average thickness of 0.78 mm and good surface texture.

[0178] (Comparative Example 1: Prototype of Synthetic Leather Without a Sponge Layer, Without Gelling) A cotton knit fabric cut to a length of 30 cm and a width of 8 cm was impregnated with water in an amount equivalent to 180% of the weight of the cotton knit fabric and coated with approximately 50 g of the BCP solution A prepared as described above to a thickness of 2.5 mm, including the base fabric. Without allowing time for gelation, after confirming that the coated solution was fluid (not gelled), the sample was immersed in 1 L of tap water at 60°C for 10 minutes to replace the solvent in the coating layer with water. Observation of the sample surface at this point confirmed that the coating layer was wavy and had uneven thickness. The above-described replacement process was repeated a total of five times to remove the DMSO, and then dried in an oven at 120°C for 60 minutes to obtain synthetic leather with an average thickness of 0.98 mm and an uneven surface.

[0179] (Example 3: Prototype of Synthetic Leather with a Porous Epidermal Layer) 1) Synthesis of BCP Solution Containing Bubbles 125.8 g of dimethyl sulfoxide (DMSO) was weighed into a three-neck flask, and 172 mg of dithiothreitol (DTT) was added as a reducing agent and stirred to dissolve. 12.0 g of artificial fibroin (polypeptide, 10 kDa) having the amino acid sequence (PRT3177) was then added, and the mixture was heated and stirred at 85°C for 30 minutes to dissolve. 12.0 g of polyethylene glycol bismaleate (molecular weight 11,000) was then added, and the mixture was heated and stirred at 85°C for 30 minutes to obtain a DMSO solution containing a polymer compound in which a polypeptide moiety and a polyethylene glycol moiety were bonded. The stirring speed during the reaction was set to 600 rpm to foam the solution, creating a BCP solution containing bubbles (BCP solution B).

[0180] 2) Method for Manufacturing Synthetic Leather: A cotton knit fabric cut to a length of 30 cm and a width of 8 cm was impregnated with water in an amount equivalent to 180% of the weight of the cotton knit fabric and coated with approximately 50 g of the BCP solution B prepared as described above to a thickness of 3 mm, including the base fabric. After gelation for 60 minutes at 20°C and 65% RH, and confirming that the fluidity of the coated solution had been lost, the fabric was immersed in 1 L of tap water at 60°C for 10 minutes to replace the solvent in the coating layer with water. In this state, the viscosity of the coated solution was 50,000 mPa·s or greater. This replacement process was repeated five times to remove the DMSO, and the fabric was then dried in an oven at 120°C for 60 minutes to obtain a soft synthetic leather with an average thickness of 1.04 mm and good surface texture.

[0181] Example 4: Prototype production of synthetic leather with a porous surface layer using a short gelation time. A piece of cotton knit fabric cut to 30 cm length and 8 cm width was impregnated with water in an amount equivalent to 180% of the cotton knit fabric's weight and coated with approximately 50 g of the BCP solution B prepared as described above to a thickness of 3 mm, including the base fabric. After gelation for 10 minutes at 20°C and 65% RH, and confirmation that the coating solution had lost its fluidity, the fabric was immersed in 1 L of tap water at 60°C for 10 minutes to replace the solvent in the coating layer with water. In this state, the viscosity of the coating solution was 50,000 mPa·s or greater. The above-described replacement process was repeated five times to remove the DMSO, and the fabric was then dried in a 120°C oven for 60 minutes to obtain a soft synthetic leather with an average thickness of 1.13 mm and good surface texture.

[0182] (Comparative Example 2: Prototype of Synthetic Leather with a Porous Surface Layer, Without Gelling) A cotton knit fabric cut to a length of 30 cm and a width of 8 cm was impregnated with water in an amount equivalent to 180% of the weight of the cotton knit fabric and coated with approximately 50 g of BCP solution B prepared as described above to a thickness of 3 mm, including the base fabric. Without allowing time for gelation, after confirming that the coated solution was fluid (not gelled), the sample was immersed in 1 L of tap water at 60°C for 10 minutes to replace the solvent in the coating layer with water. Observation of the sample surface at this point confirmed that the coating layer was wavy and had uneven thickness. The above-described replacement process was repeated a total of five times to remove the DMSO, and then the sample was dried in an oven at 120°C for 60 minutes to obtain synthetic leather with an average thickness of 1.09 mm and an uneven surface.

[0183] (Example 5: Prototype of Multilayered Synthetic Leather by Layering) A cotton knit fabric cut to a length of 30 cm and a width of 8 cm was impregnated with water in an amount equivalent to 180% of the weight of the cotton knit fabric and coated with approximately 40 g of the bubble-containing BCP solution B prepared as described above to a thickness of 3 mm, including the base fabric. The first coating layer was formed by gelling at room temperature for 5 minutes, and then approximately 30 g of bubble-free BCP solution A was coated on top to a thickness of 3.5 mm, including the base fabric and first coating layer. The second coating layer was formed by gelling for 60 minutes at 20°C and 65% RH. After confirming that the fluidity of the coating solution in each coating layer had been lost, the fabric was immersed in 1 L of tap water at 60°C for 10 minutes, and the solvent in each coating layer was replaced with water. In the fluidity-depleted state, the viscosity of the coating solution was 50,000 mPa·s or greater. The above-mentioned replacement procedure was repeated a total of seven times to remove the DMSO, and then the leather was dried in an oven at 120° C. for 90 minutes to obtain a synthetic leather having a thickness of 1.21 mm, which was soft and had a good surface texture.

[0184] (Example 6: Prototype of Multilayered Synthetic Leather by Multiple Coatings with a Short Gelling Time) A cotton knit fabric cut to 30 cm length and 8 cm width was impregnated with water in an amount equivalent to 180% of the cotton knit fabric's weight and coated with approximately 40 g of the bubble-containing BCP solution B prepared as described above to a thickness of 3 mm, including the base fabric. The first coating layer was allowed to gel at room temperature for 5 minutes, and then approximately 30 g of bubble-free BCP solution A was coated on top to a thickness of 3.5 mm, including the base fabric and first coating layer. The second coating layer was allowed to gel for 10 minutes at 20°C and 65% RH. After confirming that the fluidity of the coating solution in each coating layer had been lost, the fabric was immersed in 1 L of tap water at 60°C for 10 minutes, and the solvent in each coating layer was replaced with water. In the fluidity-depleted state, the viscosity of the coating solution was 50,000 mPa·s or greater. The above-mentioned replacement procedure was repeated a total of seven times to remove the DMSO, and then the leather was dried in an oven at 120° C. for 90 minutes to obtain a soft synthetic leather with a thickness of 1.16 mm and good surface texture.

[0185] Comparative Example 3: Prototype of Multilayered Synthetic Leather by Layering Coatings Without Gelling. A cotton knit fabric cut to a length of 30 cm and a width of 8 cm was impregnated with water in an amount equivalent to 180% of the weight of the cotton knit fabric. Approximately 40 g of the bubble-containing BCP solution B prepared as described above was coated to a thickness of 3 mm, including the base fabric. The first coating layer was formed by gelling at room temperature for 5 minutes, and then approximately 30 g of bubble-free BCP solution A was coated on top of the first coating layer to a thickness of 3.5 mm, including the base fabric and first coating layer, to form a second coating layer. For the second coating layer, no gelling time was allowed. After confirming that the bubble-free solution had fluidity (no gelation), the sample was immersed in 1 L of tap water at 60°C for 10 minutes, and the solvent in each coating layer was replaced with water. Observation of the sample surface at this point confirmed that the coating layer was wavy and had uneven thickness. The above-mentioned replacement procedure was repeated a total of seven times to remove the DMSO, and then the leather was dried in an oven at 120° C. for 90 minutes to obtain synthetic leather having an uneven surface and an average thickness of 1.28 mm.

[0186] Correspondence between Examples and Comparative Examples and Manufacturing Conditions The correspondence between each Example and Comparative Example and each condition of coating layer structure and gelation time is summarized in the table below. In the table below, "non-porous structure" refers to synthetic leather without a sponge layer, "porous structure" refers to synthetic leather with a porous surface layer, and "multi-layer structure" refers to synthetic leather with multiple layers formed by multiple coatings.

[0187] (Table 2)

[0188] Result 1: Surface Roughness Measurements The synthetic leathers obtained under each manufacturing condition were cut into pieces approximately 5-10 mm square, and the arithmetic mean height (Sa) of 12 points was measured using the roughness measurement function of a tabletop scanning electron microscope (Phenom ProX, manufactured by Thermo Fisher Scientific). The magnification during measurement was 400x, and the field of view was 810.94 μm. The arithmetic mean height (Sa) of the sample was determined by averaging the data from 10 points, excluding the maximum and minimum results of the 12 arithmetic mean heights. The relationship between the results and gelation time is shown in Figure 2. Figure 2 indicates that the arithmetic mean height (Sa) of non-porous and multi-layered synthetic leathers decreased significantly with a gelation time of 10 minutes or more, indicating that gelation significantly improved the surface properties. On the other hand, the porous synthetic leathers had a large Sa even when the gelation time was 10 minutes or more. This is due to the presence of numerous irregularities on the surface resulting from the porous structure, and it is clear that this is not suitable for applications requiring surface smoothness. However, even for synthetic leather with a porous structure, the arithmetic mean height for the condition of 0 minutes of gelation (no gelation) was greater than for the condition of 10 minutes or more of gelation (with gelation), indicating that gelation improves surface smoothness.

[0189] Result 2: Relationship between gelation time and thickness variation. The thickness of synthetic leathers obtained under each manufacturing condition was measured at nine points, and the relationship between the calculated thickness coefficient of variation and gelation time is shown in Figure 3. Thickness was measured using a constant-pressure thickness gauge (FFD-2, manufactured by Ozaki Seisakusho) with a 5 mm probe diameter and a measuring force of 0.8 N or less. The results in Figure 3 indicate that, regardless of the coating layer configuration, the longer the gelation time, the smaller the thickness coefficient of variation. It was confirmed that under conditions in which the solution lost fluidity and gelled before proceeding to the process of replacing the coating layer solvent with water (gelation conditions of 10 minutes or more), the thickness coefficient of variation was below 5% for all samples. These results demonstrate that gelation is effective in ensuring thickness precision, and that longer gelation times increase thickness precision.

[0190] Results 3: Basic Physical Properties The average thickness, basis weight, and tensile properties of synthetic leathers (Examples 1, 3, and 5) with a gelation time of 60 minutes are summarized in the table below. Tensile tests were performed at a temperature of 20°C and humidity of 65% using a universal testing machine (Shimadzu Corporation, AG-Xplus) at a tensile speed of 10 mm / min, and the values ​​represent the average of three measurements. The thickness and basis weight results indicated that the porous and multilayer synthetic leathers had a smaller basis weight and maintained lightness despite their increased thickness compared to non-porous structures. Furthermore, when focusing on the elastic modulus and maximum point stress during tension, the porous and multilayer structures exhibited lower values ​​compared to non-porous structures, indicating softness despite inferior strength. On the other hand, there was no significant difference in maximum point elongation, confirming that it followed the elongation of the cotton knit fabric base regardless of structure. These results demonstrate that various properties such as thickness, basis weight, softness, and surface properties can be controlled by selecting the structure according to the purpose.

[0191] (Table 3)

[0192] Result 4: Cross-sectional SEM Observation The cross-sections of the synthetic leathers obtained under each manufacturing condition are shown in Figures 4 to 12. The cross-sections were photographed using a tabletop scanning electron microscope (Phenom ProX, manufactured by Themo Fisher Scientific) at a magnification of 400x, with only a portion of the base fabric layer included in the field of view. Figure 4 shows the results for Example 1, Figure 5 for Example 2, Figure 6 for Comparative Example 1, Figure 7 for Example 3, Figure 8 for Example 4, Figure 9 for Comparative Example 2, Figure 10 for Example 5, Figure 11 for Example 6, and Figure 12 for Comparative Example 3. These results also confirmed that the upper surface of the synthetic leather with a gelation time of 0 minutes was not smooth and had poor surface properties.

[0193] Example 7: Prototype of multi-layered synthetic leather without gelling before recoating

[0194] 1) Synthesis of Bubble-Free BCP Solution: 122.8 g of dimethyl sulfoxide (DMSO) was weighed into a three-neck flask, and 194 mg of dithiothreitol (DTT) was added as a reducing agent and stirred to dissolve. Then, 13.5 g of artificial fibroin (polypeptide, 10 kDa) having the amino acid sequence (PRT3177) was added, and the mixture was heated and stirred at 85°C for 30 minutes to dissolve. 13.5 g of polyethylene glycol bismaleate (molecular weight 11,000) was then added, and the mixture was heated and stirred at 85°C for 30 minutes to obtain a DMSO solution containing a polymer compound in which a polypeptide moiety and a polyethylene glycol moiety were bonded. The stirring speed during the reaction was 300 rpm, and bubbles were present in the solution. After the reaction, the reaction vessel was depressurized using a diaphragm pump (Yamato Scientific, PG201) to remove the bubbles, resulting in a degassed BCP solution (BCP Solution C).

[0195] 2) Synthetic Leather Manufacturing Method: A cotton knit fabric cut to a length of 33 cm and a width of 24 cm was impregnated with water in an amount equivalent to 180% of the cotton knit fabric's weight and coated with 150 g of the bubble-containing BCP solution B prepared as described above to a thickness of 4 mm, including the base fabric. Immediately thereafter, approximately 100 g of bubble-free BCP solution C was coated with the base fabric and the first coating layer to a thickness of 4.5 mm, including the base fabric and the first coating layer. At this time, the first and second coating solutions mixed, forming a marbled pattern. After gelling overnight at 20°C and 65% RH, and confirming that the coating solution had lost its fluidity, the fabric was immersed in 1 L of tap water at 60°C for 10 minutes to replace the solvent in the coating layer with water. This replacement process was repeated a total of seven times to remove the DMSO, and then dried in a 120°C oven for 120 minutes to obtain a synthetic leather with a thickness of 1.40 mm.

[0196] Result 5: Measurement of surface roughness and SEM observation The arithmetic mean height Sa of the synthetic leather of Example 7 was calculated using the method described in Result 1, and is shown in the following table together with the results of Example 5. Table 4 shows that coating the second layer after gelling the coating solution of the first layer resulted in a greater improvement in surface properties (a decrease in Sa) than by extending the gelling time after coating the second layer.

[0197] (Table 4) The cross section and surface of the synthetic leather of Example 7 were photographed using the method described in Result 4, and are shown in Figures 13 and 14. The cross section image (Figure 13) shows that the interface between the first layer containing bubbles and the second layer without bubbles is not smooth and undulates vertically. Furthermore, the surface image (Figure 14) shows that cavities have formed in the outermost layer, confirming that the coating solutions of the first and second layers have mixed, causing the layer containing bubbles to reach the surface. From the above, it was demonstrated that when coating multiple times, gelling after each coating is effective for ensuring multilayering and surface smoothness.

[0198] According to the present disclosure, there is provided a method for producing a laminate having an excellent surface property, the laminate having a skin layer formed from a polymer compound containing a protein structure.

[0199] 1 Skin layer 2 Fabric layer 10 Laminate

Claims

1. A method for manufacturing a laminate, comprising: a step of forming an epidermal layer precursor gel on a member having a base fabric layer and an epidermal layer solution layer containing a polymer compound having a protein structure and a solvent by gelling the epidermal layer solution layer; a step of bringing the epidermal layer precursor gel into contact with a solvent displacement liquid to replace the solvent in the epidermal layer precursor gel with the solvent displacement liquid; and a step of removing the solvent displacement liquid from the epidermal layer precursor gel to solidify the epidermal layer precursor gel, thereby forming the epidermal layer on the base fabric layer.

2. The method for producing a laminate according to claim 1, wherein the polymer compound is a chemically modified protein.

3. The method for producing a laminate according to claim 1, wherein the polymer compound is a block copolymer containing a protein structure as a segment.

4. The method for producing a laminate according to any one of claims 1 to 3, wherein the layer of the solution for forming the surface layer contains bubbles.

5. The method for producing a laminate according to claim 3, wherein the polymer compound is a block copolymer in which a segment containing a protein structure is bonded to a segment containing a molecule capable of plasticizing a protein.

6. The method for producing a laminate according to any one of claims 1 to 3, further comprising the step of applying a solution for forming a surface skin layer onto a base fabric layer to produce the member.

7. The method for producing a laminate according to any one of claims 1 to 3, wherein the removal of the solvent displacement liquid is carried out by drying the skin layer precursor gel.

8. The method for producing a laminate according to claim 6, wherein the step of producing the member is carried out by providing the base fabric layer by a roll-to-roll method and applying the solution for forming the surface skin layer onto the base fabric layer.

9. A method for producing a laminate according to any one of claims 1 to 3, wherein, after the step of forming the epidermal layer precursor gel on the base fabric layer, the steps of applying an epidermal layer-forming solution onto the epidermal layer precursor gel to obtain an epidermal layer-forming solution layer and gelling the epidermal layer-forming solution layer to form an epidermal layer precursor gel are carried out one or more times to directly form a plurality of epidermal layer precursor gels into a laminate, and then the plurality of epidermal layer precursor gels are brought into contact with a solvent displacement liquid to replace the solvent in the epidermal layer precursor gels with the solvent displacement liquid, and the solvent displacement liquid is released from each of the epidermal layer precursor gels, thereby solidifying the plurality of epidermal layer precursor gels, thereby forming the epidermal layer in a multi-layer structure.

10. The method for producing a laminate according to claim 9, wherein at least one layer, excluding the outermost layer, of the plurality of layers of the solution for forming a surface layer is a bubble-containing layer formed using the solution for forming a surface layer containing bubbles.

11. A method for producing a laminate according to any one of claims 1 to 3, further comprising, before the step of forming the skin layer precursor gel on the fabric layer, a step of applying an intermediate layer forming solution onto the fabric layer to obtain an intermediate layer forming solution layer, and a step of applying the skin layer forming solution onto the intermediate layer forming solution layer to produce the member, wherein the intermediate layer forming solution layer is not gelled after the step of forming the skin layer precursor gel on the fabric layer.

12. A method for producing a laminate in which a foam layer and a skin layer are laminated on a base fabric layer, the method comprising: providing a foam layer-forming solution, which contains a polymer compound having a protein structure, a solvent, and bubbles, on the base fabric layer to form a foam layer-forming solution layer on the base fabric layer; gelling the foam layer-forming solution layer to form a foam layer precursor gel; providing a skin layer-forming solution, which contains a polymer compound having a protein structure and a solvent, directly on the foam layer precursor gel to form a skin layer-forming solution layer; gelling the skin layer-forming solution layer to form a skin layer precursor gel; contacting the foam layer precursor gel and the skin layer precursor gel with a solvent replacement liquid to replace the solvent in the foam layer precursor gel and the skin layer precursor gel with the solvent replacement liquid; and removing the solvent displacement liquid from the foam layer precursor gel and the skin layer precursor gel to solidify the foam layer precursor gel and the skin layer precursor gel, thereby laminating the foam layer and the skin layer on the fabric layer.

13. The method for producing a laminate according to any one of claims 1 to 3 and 12, wherein the laminate is synthetic leather.

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