Compact, wearable terminal, method for producing molding, method for producing cross-linked polymer

Abstract

To provide: a compact obtainable through spontaneous bending caused by swelling with a solvent; a wearable terminal provided with the compact; a method for producing the compact; and a method for producing a cross-linked polymer.SOLUTION: A compact comprises a base and at least one bent portion connected to the base. Therein: the base and the bent portion are constituted of a first cross-linked polymer having a first mesh structure and a second mesh structure; and when thickness of the base before the solvent is impregnated is t1, thickness of the base after the solvent is impregnated is t2, thickness of the bent portion before the solvent is impregnated is ts1, and thickness of the bent portion after the solvent is impregnated is ts2, the compact has a swelling ratio (Q) expressed by the following formula (1) that is greater than 1 and up to 5. Q=(ts2 / ts1) / (t2 / t1) (1) (on condition that t1≥ts1).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a molded article, a wearable terminal, a method for manufacturing a molded article, and a method for manufacturing a crosslinked polymer article. [Background technology]

[0002] A crosslinked polymer is a material in which linear polymer chains are crosslinked by covalent bonds to form a network. Typical examples of crosslinked polymers include vulcanized rubber, which is widely used in tires, and hydrogels, which contain water within the network. Hydrogels, which are water-containing materials, are particularly expected to be used as bioreplacement materials and biomimetic materials because their hardness (elastic modulus) and water content are similar to those of living organisms.

[0003] To put a crosslinked polymer into practical use, it is necessary to mold it into a shape suitable for the intended application. Crosslinked polymers are similar to thermosetting resins, which have an internal network structure, making it difficult to apply common processing methods such as injection molding and rolling. Conventional techniques for molding crosslinked polymers include, for example, a method of synthesizing a crosslinked polymer inside a mold having a desired shape, a method of printing a crosslinked polymer using a 3D printer (see, for example, Patent Document 1), a method of cutting a crosslinked polymer using a grinder or the like after synthesis, and a method using a hydrogel having a structure in which a second polymer penetrates into the crosslinked network structure of microparticles containing a first polymer having a crosslinked network structure (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-150761 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-163055 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the mold-based method requires the creation of a mold suited to the application, resulting in high manufacturing costs. Furthermore, the crosslinked polymer must be demolded after synthesis, making it difficult to mold crosslinked polymers with complex shapes. Furthermore, the method of printing crosslinked polymers using a 3D printer requires a long printing time and requires the use of materials with properties suitable for printing. Furthermore, cutting crosslinked polymers using a grinder or other tool is extremely difficult, especially for hydrogels, due to their flexibility. Furthermore, the method using microparticles does not provide sufficient mechanical strength for the hydrogels.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a molded body obtained by spontaneous bending due to swelling in a solvent, a wearable terminal including the molded body, a method for manufacturing the molded body, and a method for manufacturing a polymer crosslinked body. [Means for solving the problem]

[0007] The present invention has the following aspects. [1] A molded body having a base and at least one bent portion connected to the base, the base portion and the bent portion are composed of a first crosslinked polymer having a first network structure and a second network structure, The thickness of the base portion before impregnating with the solvent is t1, the thickness of the base portion after impregnating with the solvent is t2, and the thickness of the bent portion before impregnating with the solvent is t s1 The thickness of the bent portion after the solvent is impregnated is t s2 The molded article has a swelling ratio (Q) represented by the following formula (1) of greater than 1 and not greater than 5 when: Q=(t s2 / t s1 ) / (t2 / t1) (1) (However, t1 ≥ t s1 ) [2] A wearable terminal comprising: a mounting body to be mounted on an adherend; and an electronic device fixed to the mounting body, The attachment is a wearable terminal comprising the molded article according to [1]. [3] A method for producing a molded article made of a crosslinked polymer and having a base and at least one bent portion connected to the base, comprising: a step of irradiating a laser beam to an arbitrary portion of the crosslinked polymer processed into a sheet or fiber; and impregnating the crosslinked polymer with a solvent after the laser beam irradiation. [4] The thickness of the base portion before impregnating with the solvent is t1, and the thickness of the bent portion before impregnating with the solvent is t s1 The method for producing a molded article according to [3], wherein the residual ratio (r) represented by the following formula (2) is 0.01 or more and 1 or less when r=t s1 / t1(2) [5] The method for producing a molded article according to [3] or [4], wherein the crosslinked polymer has an interpenetrating network structure or a semi-interpenetrating network structure. [6] The method for producing a molded article according to [3] or [4], wherein the crosslinked polymer has an ultimate extension network structure. [7] A method for producing a crosslinked polymer having an utmost stretch network structure, comprising: introducing a first monomer into a first network structure having a cross-linked structure, polymerizing the first monomer to introduce a first molecular stent, and forming a second network structure; introducing a second monomer into the second network and polymerizing the second monomer to introduce a second molecular stent to form a third network; and introducing a third monomer into the third mesh structure, polymerizing the third monomer to introduce a third molecular stent, and forming a fourth mesh structure. [8] A method for producing a crosslinked polymer according to [7], comprising the step of immersing the fourth network structure in a solvent to swell the fourth network structure. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a molded article obtained by spontaneous bending due to swelling in a solvent, a wearable terminal including the molded article, a method for producing the molded article, and a method for producing a crosslinked polymer. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a cross-sectional view showing the state of the molded body of the present disclosure after irradiation with laser light and before bending. [Figure 2] 1 is a diagram showing the relationship between the bending angle of the bent portion and the survival rate in Example 1. FIG. [Figure 3] FIG. 1 is a diagram showing the relationship between the bending angle of the bent portion and the scraping width in the width direction of the double-network gel in Example 1. [Figure 4] 1 is a photograph showing the bending state of a double network gel in Example 2. [Figure 5] 1 is a photograph showing the bending state of polydimethylacrylamide gel in Example 2. [Figure 6] 1 is a photograph showing the bending state of polyacrylamide gel in Example 2. [Figure 7] 1 is a photograph showing the bending state of a vulcanized rubber sheet in Example 3 when the residual ratio (r) is 0.3. [Figure 8] 1 is a photograph showing the bending state of a vulcanized rubber sheet in Example 3 when the residual ratio (r) is 0.55. [Figure 9] 10 is a photograph showing the state of a double-network gel cut into a spiral shape in Example 4. [Figure 10] 10 is a photograph showing a state in which a double-network gel cut into a spiral shape is immersed in pure water in Example 4. [Figure 11] 10 is a photograph showing the state in which the double network gel has been cut into the shape of an unfolded box in Example 4. [Figure 12] 10 is a photograph showing the state of a double network gel cut into the shape of an unfolded box and immersed in pure water in Example 4. [Figure 13]10 is a photograph showing the behavior of a gel folded into a box shape when immersed in a 50% by mass aqueous ethanol solution in Example 5. [Figure 14] 1 is a photograph showing the bending state of a double network gel in Example 6. [Figure 15] 10 is a photograph showing the bending state of poly-N-isopropylacrylamide gel in Example 7. [Figure 16] 10 is a photograph showing the bending state of poly-N-isopropylacrylamide gel in Example 7. [Figure 17] FIG. 10 is a diagram showing the relationship between the bending angle of the bent portion and the survival rate in Example 7. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments and examples of the present disclosure will be described with reference to the drawings, etc. However, the present disclosure can be implemented in many different forms, and should not be construed as being limited to the description of the embodiments and examples exemplified below. Furthermore, to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part more schematically than the actual form, but these are merely examples and do not limit the interpretation of the present disclosure. In addition, in this specification, the use of "to" to indicate a range of values ​​means that the values ​​before and after it are included as the lower limit and upper limit.

[0011] [Crosslinked polymer] The crosslinked polymer of the present disclosure refers to a material having at least one polymer network structure in which polymer chains are crosslinked to form a network, and may contain a solvent, another linear polymer, a polymer crosslinked to form a network, or other substances. Here, the crosslinking may be crosslinking by covalent bonds or crosslinking by non-covalent bonds such as hydrogen bonds or ionic bonds.

[0012] The crosslinked polymer preferably has an interpenetrating network structure or a semi-interpenetrating network structure. An interpenetrating network structure is a structure in which at least two types of polymer networks are independently entangled with each other. A crosslinked polymer having an interpenetrating network structure has at least a first network structure and a second network structure. The first network structure is a network structure of a crosslinked polymer in which polymer chains are crosslinked with each other. The second network structure is a structure in which other crosslinked network structures are uniformly entangled throughout the first network structure, resulting in the formation of multiple network structures within the crosslinked polymer. A semi-interpenetrating network structure is a structure in which at least one type of polymer network and at least one type of non-crosslinked polymer chain are independently entangled with each other.

[0013] An example of a crosslinked polymer having an interpenetrating network structure is a double network gel containing a solvent such as water.

[0014] Examples of crosslinked polymers having a semi-interpenetrating network structure include crosslinked polymers that are composed of a first network structure having multiple crosslinking points and a linear polymer, in which the first network structure and the non-crosslinked linear polymer are physically entangled with each other via the network.

[0015] The crosslinked polymer preferably has an ultimate stretched network structure. An ultimate stretched network structure is a double network structure in which a polymer network with significantly stretched network chains is combined with another polymer network. Crosslinked polymers having an ultimate stretched network structure are susceptible to destruction by laser light irradiation due to tension applied to the ultimate stretched network structure portion, and are therefore suitable for forming bent portions in the molded articles described below. Crosslinked polymers having an ultimate stretched network structure have an extremely high elastic modulus per unit active ingredient density, making them suitable as high-elasticity gels. Furthermore, crosslinked polymers having an ultimate stretched network structure are capable of absorbing water up to near the stretch limit of their network chains, making them suitable as highly water-absorbent gels. Furthermore, crosslinked polymers having an ultimate stretched network structure can be synthesized regardless of the chemical structure of the network chains or the type of solvent, allowing for a wide range of chemical species to be selected, making them suitable for a variety of applications. Crosslinked polymers having an ultimate stretched network structure are characterized by collapse upon overswelling.

[0016] Examples of crosslinked polymers having an utmost stretched network structure include crosslinked polymers having a triple network structure or a quadruple network structure, and crosslinked polymers having a semi-interpenetrating network structure having two or more types of non-crosslinked polymer chain components.

[0017] [Method of manufacturing crosslinked polymer] The method for producing a crosslinked polymer according to the present disclosure is a method for producing a crosslinked polymer having an utmost stretched network structure, and includes the steps of: introducing a first monomer into a first network having a crosslinked structure, polymerizing the first monomer to introduce a first molecular stent, thereby forming a second network structure (hereinafter referred to as "Step A1"); introducing a second monomer into the second network structure, polymerizing the second monomer to introduce a second molecular stent, thereby forming a third network structure (hereinafter referred to as "Step B1"); and optionally, introducing a third monomer into the third network structure, polymerizing the third monomer to introduce a third molecular stent, thereby forming a fourth network structure (hereinafter referred to as "Step C1"). The second to fourth mesh structures formed by introducing the first to third molecular stents may not be cross-linked. In this case, the polymers comprising the molecular stents contain non-cross-linked linear polymers and are physically entangled with the first mesh structure and other mesh structures.

[0018] "Process A1" In step A1, a first monomer is introduced into a first network structure having a crosslinked structure, and the first monomer is polymerized to introduce a first molecular stent, thereby forming a second network structure.

[0019] The first network structure having a crosslinked structure is preferably, for example, a network structure having a chemically crosslinked structure. The shape of the network structure may be a massive network structure that exists continuously throughout, or a particulate network structure. In particular, to obtain a high-strength polymer gel, the former massive network structure is preferable. Furthermore, the particulate network structure may be, for example, one obtained by pulverizing the massive network structure.

[0020] The monomer constituting the first network structure can be any known monomer without any particular restrictions, including, for example, electrically neutral unsaturated monomers, charged unsaturated monomers, and copolymers thereof.

[0021] Examples of electrically neutral unsaturated monomers include acrylamide monomers such as acrylamide (AAm), N-isopropylacrylamide (NIPAM), and dimethylacrylamide (DMAAm); vinyl monomers such as vinyl acetate, vinylpyridine, and styrene (St); alkyl acrylate monomers such as methyl methacrylate; hydroxyalkyl acrylate monomers such as hydroxyethyl acrylate (HEA); and fluorine-containing unsaturated monomers such as trifluoroethyl acrylate.

[0022] Suitable examples of the charged unsaturated monomer include unsaturated monomers having an acidic group (e.g., a carboxyl group, a phosphoric acid group, or a sulfonic acid group) or a basic group (e.g., an amino group), such as 2-acrylamido-2-methylpropanesulfonic acid (AMPS), acrylic acid (AAc), methacrylic acid, or salts thereof.

[0023] The crosslinking agent is not particularly limited, and any known crosslinking agent that forms a chemical crosslink can be used, but various ones can be selected depending on the organic monomer to be crosslinked and polymerized, for example, an acrylic crosslinking agent having two or more (meth)acrylic groups. More specifically, when AMPS, AAm, or AAc is used as the organic monomer, N,N'-methylenebisacrylamide can be used, and when St is used as the organic monomer, ethylene glycol dimethacrylate can be used.

[0024] The first network structure may be a multifunctional polymer crosslinked to form a three-dimensional network structure. The multifunctional polymer preferably contains one or both of the following P1 and P2. P1: A hyperbranched polymer having three or more branching points and three or more functional groups. P2: A linear polymer with no branching points with three or more branches and two functional groups.

[0025] The crosslinked polymer may be one obtained by crosslinking between polyfunctional polymers, or one obtained by crosslinking between a polyfunctional polymer and a polyfunctional monomer (crosslinking agent). Preferred embodiments of the crosslinked polymer having a three-dimensional network structure include, for example, the following embodiments 1 to 5. The crosslinked polymer preferably includes one or more types selected from the group consisting of the crosslinked polymers of the following embodiments 1 to 5. Aspect 1: A crosslinked polymer in which one or more types of P1 are crosslinked. Aspect 2: A crosslinked polymer in which one or more types of P1 are crosslinked with one or more types of P2. Aspect 3: A crosslinked polymer in which one or more types of P1 are crosslinked with one or more types of Q1 below. Aspect 4: A crosslinked polymer in which one or more types of P1 are crosslinked with one or more types of Q2 below. Aspect 5: A crosslinked polymer in which one or more types of P2 are crosslinked with one or more types of Q1 below. Q1: Branched monomers with three or more functional groups. Q2: A bifunctional monomer having two functional groups.

[0026] The functional groups P1, P2, Q1, and Q2 are reactive groups capable of crosslinking, and known reactive groups can be used. The crosslinking reaction may be a reaction between one type of functional group or a reaction between two types of functional groups, and any known crosslinking reaction can be used. As an example of a crosslinking reaction between two types of functional groups, a crosslinking reaction in which a nucleophilic functional group and an electrophilic functional group form a covalent bond is known as an AB cross-end coupling reaction (Matsunaga et al., Macromolecules, Vol. 42, No. 4, pp. 1344-1351, 2009). As the combination of the nucleophilic functional group and the electrophilic functional group, a known combination can be used. Examples of the nucleophilic functional group include a thiol group (-SH), an amino group, or -COOPhNO2 (Ph represents an o-, m-, or p-phenylene group). The electrophilic functional group may be an active ester group. Examples of the active ester group include a maleimidyl group, an N-hydroxysuccinimidyl (NHS) group, a sulfosuccinimidyl group, a phthalimidyl group, an imidazolyl group, an acryloyl group, and a nitrophenyl group. Other known active ester groups may also be used as appropriate. Examples of crosslinking reactions of one type of functional group include a reaction between thiol groups and a reaction between maleimide groups.

[0027] [P1: Hyperbranched polymer] The hyperbranched polymer P1 is a polymer having a branch point from which three or more branched chains emerge and having three or more functional groups. The number of branched chains extending from one branch point is preferably 3 to 8, more preferably 3 to 6, and particularly preferably 4. The branched chain has a polymer chain composed of units based on one or more types of monomer. The monomer constituting the polymer chain is not particularly limited as long as it is a monomer capable of constituting a multi-branched polymer. Known monomers can be used. Examples include ethylene glycol and vinyl compounds. Examples of vinyl compounds include (meth)acrylic acid or its derivatives, and styrene or its derivatives. The functional group of the hyperbranched polymer may be present at the end of a branched chain or in a pendant group (a group not containing a polymer chain) of the branched chain, but is preferably present at the end of a branched chain. It is preferable that the structures of the branched chains constituting one molecule of the hyperbranched polymer are the same. The weight average molecular weight per branch chain of the hyperbranched polymer is preferably 500 to 500,000, more preferably 1,000 to 100,000, and even more preferably 5,000 to 50,000. As the hyperbranched polymer constituting the crosslinked polymer, a hyperbranched polymer (hereinafter also referred to as "PEG polymer") in which the branched chain has a polyethylene glycol skeleton, which is a polymer chain of ethylene glycol, is preferred.

[0028] [P2: Linear polymer] The linear polymer P2 is a polymer having two functional groups. A linear polymer has a polymer chain made up of units based on one or more types of monomer. A linear polymer does not have a branch point from which three or more branches emanate, i.e., linear polymers do not include hyperbranched polymers. The monomer constituting the polymer chain is not particularly limited as long as it can form a linear polymer. Known monomers can be used. Examples include ethylene glycol and vinyl compounds. Examples of vinyl compounds include (meth)acrylic acid or its derivatives, and styrene or its derivatives. The functional group of the linear polymer may be attached to the end of the polymer chain directly or via a linker, or may be present as a pendant group of the polymer chain, preferably attached to the end of the polymer chain directly or via a linker. The weight average molecular weight of the linear polymer is preferably from 500 to 500,000, more preferably from 1,000 to 100,000, and even more preferably from 5,000 to 50,000. An example of a linear polymer that constitutes a crosslinked polymer is a polymer having a polyethylene glycol backbone, which is a polymer chain of ethylene glycol, and having functional groups at both ends.

[0029] [Q1: Branched monomer] The branched monomer Q1 is a monomer (crosslinking agent) having three or more functional groups. A branched monomer typically has a carbon-containing backbone and three or more functional groups attached to the backbone. A branched monomer does not contain a polymer chain. The functional group of the branching monomer may be present at the molecular terminal or as a pendant group on the backbone portion. The branching monomer may be a homopolyfunctional crosslinking agent in which three or more reactive groups are the same, or a heteropolyfunctional crosslinking agent in which the reactive groups are different from one another. The molecular weight of the branched monomer is preferably 30 or more and less than 500, more preferably 40-400, and even more preferably 50-300. As the branching monomer, a known crosslinking agent having three or more functional groups can be used, such as methanetriol, 1,2,4-butanetriol, trimethylolpropane, erythritol, pentaerythritol, dipentaerythritol, 2,2'-diethyl-2,2'-[[2-ethyl-2-(hydroxymethyl)propane-1,3-diyl]bis(oxymethylene)]bis(propane-1,3-diol), bis-trispropane, 2-amino-2-hydroxymethyl-1,3-propanediol, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, diethylenetriamine, and asparagine.

[0030] [Q2: Difunctional monomer] The bifunctional monomer Q2 is a monomer (crosslinking agent) having two functional groups. A bifunctional monomer typically has a carbon-containing backbone and two functional groups attached to the backbone. The backbone does not contain a polymer chain. That is, a bifunctional monomer does not include the linear polymer. The functional groups of the bifunctional monomer may be present at the molecular terminals or as pendant groups in the backbone portion. The bifunctional monomer may be a homobifunctional crosslinker in which two or more reactive groups are the same, or a heterobifunctional crosslinker in which the reactive groups are different from one another. The molecular weight of the bifunctional monomer is preferably 30 or more and less than 500, more preferably 40-400, and even more preferably 50-300. As the bifunctional monomer, a known crosslinking agent having two functional groups can be used, such as methanediol, ethylene glycol, diethylene glycol, dipropylene glycol, ethylenediamine, oxalic acid, maleic acid, adipic acid, lactic acid, and alanine.

[0031] The first monomer may be, for example, the same monomer as that constituting the first network structure described above.

[0032] The amount of the first monomer added per 100 parts by mass of the first network structure is preferably 10 to 5,000 parts by mass, more preferably 50 to 3,000 parts by mass, and even more preferably 200 to 2,000 parts by mass. When the amount of the first monomer added is equal to or greater than the lower limit, the first molecular stent obtained by polymerization of the added monomer can promote swelling of the first network structure. When the amount of the first monomer added exceeds the upper limit, cracks are likely to occur in the gel during the subsequent swelling process, which is undesirable. When the amount is less than the lower limit, swelling does not occur due to an insufficient amount of polymer.

[0033] The method for polymerizing the first monomer is not particularly limited, and examples include methods using a polymerization initiator. Known polymerization initiators can be used, but various initiators are selected depending on the organic monomer to be polymerized. For example, when thermally polymerizing AMPS, AAm, or AAc as organic monomers, water-soluble thermal catalysts such as potassium persulfate or redox initiators such as potassium persulfate-sodium thiosulfate can be used. When photopolymerizing, 2-oxoglutaric acid can be used as a photosensitizer. When thermally polymerizing St as an organic monomer, organic solvent-soluble thermal catalysts such as azobisisobutyronitrile (AIBN) or benzoyl peroxide (BPO) can be used. When photopolymerizing, benzophenone can be used as a photosensitizer.

[0034] The first molecular stent obtained by polymerization of the first monomer is a substance that has the effect of expanding the mesh structure. In other words, a substance with such an effect is called a molecular stent because it functions like a stent, a medical device that widens blood vessels.

[0035] Specifically, the second network structure obtained by the first step has a structure in which the first network structure is uniformly entangled throughout the entire structure.

[0036] "Process B1" In step B1, a second monomer is introduced into the first and second mesh structures obtained in step A1, and the second monomer is polymerized to introduce a second molecular stent, thereby forming a third mesh structure.

[0037] The second monomer may be, for example, the same monomer as that constituting the first network structure.

[0038] The amount of the second monomer added per 100 parts by mass of the second network structure is preferably 10 to 5,000 parts by mass, more preferably 50 to 3,000 parts by mass, and even more preferably 200 to 2,000 parts by mass. If the amount of the second monomer added is equal to or greater than the lower limit, the second molecular stent obtained by polymerization of the added monomer can promote swelling of the second network structure. If the amount of the second monomer added is equal to or greater than the upper limit, cracks are likely to occur in the gel during the subsequent swelling process, which is undesirable. If the amount is less than the lower limit, swelling does not occur due to an insufficient amount of polymer.

[0039] The second monomer can be polymerized, for example, by the same method as the above-described method for polymerizing the first monomer.

[0040] The second molecular stent obtained by polymerization of the second monomer has the effect of expanding the first and second network structures.

[0041] Specifically, the third network structure obtained in step B1 has a structure in which the first and second network structures are uniformly entangled throughout the entire structure.

[0042] "Process C1" In step C1, a third monomer is introduced into the first, second, and third mesh structures obtained in step B1, and the third monomer is polymerized to introduce a third molecular stent, thereby forming a fourth mesh structure.

[0043] The third monomer may be, for example, the same monomer as the first monomer described above.

[0044] The amount of the third monomer added per 100 parts by mass of the third network structure is preferably 10 to 5,000 parts by mass, more preferably 50 to 3,000 parts by mass, and even more preferably 200 to 2,000 parts by mass. If the amount of the third monomer added is equal to or greater than the lower limit, the second molecular stent obtained by polymerization of the added monomer can promote swelling of the second network structure. If the amount of the third monomer added is equal to or greater than the upper limit, cracks are likely to occur in the gel during the subsequent swelling process, which is undesirable. If the amount is less than the lower limit, swelling does not occur due to an insufficient amount of polymer.

[0045] The third monomer can be polymerized, for example, by the same method as the above-described method for polymerizing the first monomer.

[0046] The third molecular stent obtained by polymerization of the third monomer has the effect of expanding the first, second and third network structures.

[0047] Specifically, the fourth network structure obtained in step C1 has a structure in which the first, second, and third network structures are uniformly entangled throughout the entire structure.

[0048] "Process D1" The method for producing a crosslinked polymer of the present disclosure may include a step of immersing the first, second, third, and fourth network structures obtained in step C1 in a solvent to swell the fourth network structure (hereinafter referred to as "step D1").

[0049] According to the method for producing a crosslinked polymer of the present disclosure, a crosslinked polymer having an utmost stretched network structure can be produced.

[0050] [Molded body] FIG. 1 is a cross-sectional view showing a molded article of the present disclosure. As shown in FIG. 1 , the molded body 1 of the present disclosure includes a base 2 and a bent portion 3 connected to the base 2, which bends when swollen by immersion in a solvent. The thickness of the bent portion 3 may be thinner than the thickness of the base 2. That is, along the thickness direction of the molded body 1, the inner bottom surface 3a of the bent portion 3 (the laser irradiated side of the bent portion) may be located lower than the upper surface 2a of the base 2. In another example, the thickness of the bent portion 3 may be the same as the thickness of the base 2. In this case, at least one of the meshes from the first mesh to the fourth mesh is destroyed, and the bent portion bends when swollen by immersion in a solvent.

[0051] The base portion 2 and the bent portion 3 are composed of a first crosslinked polymer having a first network structure and a second network structure, or a crosslinked polymer further having a third network structure and / or a fourth network structure. The base 2 is a region that is not irradiated with laser light in a method for producing a molded body described later, and the bent portion 3 is a region that is irradiated with laser light in a method for producing a molded body described later. The bent portion 3 is a region in which the network structure of the crosslinked polymer that constitutes the base 2 is removed by irradiation with laser light, and the bent portion 3 has a thickness smaller than that of the base 2. In another example, when the amount of laser light irradiation is small, the network structure of the crosslinked polymer that constitutes the bent portion 3 does not need to be removed, and the bent portion 3 is a region with a thickness equivalent to that of the base 2.

[0052] In the molded body 1, the thickness of the base 2 before impregnating with the solvent is t1, the thickness of the base 2 after impregnating with the solvent is t2, and the thickness of the bent portion 3 before impregnating with the solvent is t s1 The thickness of the bent portion 3 after impregnation with the solvent is t s2 In this case, the swelling ratio (Q) represented by the following formula (1) is greater than 1 and equal to or less than 5, preferably greater than 1.1 and equal to or less than 3, and more preferably greater than 1.5 and equal to or less than 2.5. Q=(t s2 / t s1 ) / (t2 / t1) (1) (However, t1 ≥ t s1 )

[0053] If the swelling ratio (Q) is greater than the upper limit, the material will be destroyed due to a mismatch in the swelling ratio between the base portion 2 and the bent portion 3. If the swelling ratio (Q) is less than the lower limit, the molded body 1 will not bend spontaneously, and the purpose of molding will not be achieved.

[0054] The thickness t1 of the base 2 before impregnation with the solvent, the thickness t2 of the base 2 after impregnation with the solvent, and the thickness t of the bent portion 3 before impregnation with the solvent s1 , the thickness t of the bent portion 3 after impregnation with the solvent s2 can be measured by any thickness measuring device, for example, a micrometer.

[0055] The thickness of the base portion 2 before impregnation with the solvent is t1, and the thickness of the bent portion 3 before impregnation with the solvent is t s1 is not particularly limited and can be any thickness.

[0056] The crosslinked polymer constituting the base 2 and the bending portion 3 is not particularly limited, and examples thereof include polyacrylamide, poly-N,N-dimethylacrylamide, poly-N-isopropylacrylamide, poly-2-acrylamido-2-methylpropanesulfonic acid, vulcanized natural rubber, polydimethylsiloxane, etc. When the crosslinked polymer has an interpenetrating network structure or a semi-interpenetrating network structure, the two or more polymer components contained in the crosslinked polymer may be composed of the same chemical species or different chemical species.

[0057] When the molded article 1 of the present disclosure is immersed in a solvent, more solvent is impregnated near the inner bottom surface 3a of the bent portion 3 formed by irradiating the crosslinked polymer with laser light than near the base portion 2 not irradiated with laser light or near the bottom surface 3b of the bent portion 3 opposite the side irradiated with laser light (the side opposite the laser-irradiated side of the bent portion). This causes the bent portion 3 to swell more than near the base portion 2 of the bent portion 3 or the bottom surface 3b of the bent portion 3, resulting in the bent portion 3 bending with the surface opposite to the inner bottom surface 3a (the surface not irradiated with laser light) facing outward. Furthermore, the bend angle of the bent portion 3 can be controlled by adjusting the amount of solvent impregnated into the bent portion 3 through the selection of the solvent type, thereby adjusting the degree of swelling of the bent portion 3, and thus the shape of the molded article can be controlled. Furthermore, the molded article 1 of the present disclosure can memorize its shape by adjusting the degree of swelling of the bent portion 3.

[0058] [Method of manufacturing molded body] The method for producing a molded article of the present disclosure is a method for producing a molded article made of a crosslinked polymer and having a base and at least one bent portion connected to the base, and includes the steps of irradiating a laser beam to any portion of a crosslinked polymer processed into a sheet or fiber (hereinafter referred to as "step A2"), and impregnating the crosslinked polymer with a solvent after the irradiation with the laser beam (hereinafter referred to as "step B2").

[0059] "Process A2" In step A2, a laser beam is irradiated to an arbitrary portion of the crosslinked polymer that has been processed into a sheet or fiber shape, to form a bent portion at the arbitrary portion of the crosslinked polymer that is thinner than the remaining portion (base portion). The crosslinked polymer may be any of those described above. The crosslinked polymer preferably has an interpenetrating network structure or a semi-interpenetrating network structure. Furthermore, the crosslinked polymer preferably has an ultimate stretch network structure.

[0060] The wavelength of the laser light irradiated to any part of the crosslinked polymer is preferably 350 nm or more and 10,600 nm or less. When the wavelength of the laser light is equal to or more than the lower limit, the network structure of the crosslinked polymer can be destroyed by irradiation with the laser light, changing the swelling property of the crosslinked polymer and forming a bent portion in the crosslinked polymer. When the wavelength of the laser light is equal to or less than the lower limit, the network structure of the crosslinked polymer cannot be destroyed by irradiation with the laser light, changing the swelling property, and forming a bent portion in the crosslinked polymer cannot be formed.

[0061] As a laser light source for irradiating any part of the crosslinked polymer, a solid-state laser, semiconductor laser, or gas laser that emits infrared rays is suitable. The laser light source preferably has an output of 100 mW or more, and an irradiation energy of 10 mJ / cm. 2 ~10J / cm 2 The gas laser is preferably a CO2 pulsed laser.

[0062] [Infrared absorber] The molded article according to the present disclosure may further contain an infrared absorbing agent in the network structure of the crosslinked polymer, from the viewpoint of efficiently destroying the network structure of the crosslinked polymer. The infrared absorbing agent is preferably a compound having a maximum absorption in the wavelength range of 750 nm to 1400 nm. Infrared absorbers that can be used in the present disclosure include those known as "photothermal conversion materials." The photothermal conversion material is preferably one that absorbs infrared rays and converts them into heat. Although the photothermal conversion material is not essential for forming the bent portion 3 by laser light irradiation, the network structure of the crosslinked polymer containing the photothermal conversion material can also be formed using a high-temperature body, such as a thermal head or a thermal head array.

[0063] The photothermal conversion material may be any material capable of absorbing infrared light and converting it to heat. Suitable materials include dyes and pigments. Suitable pigments include, for example, carbon black, Heliogen Green, Nigrosine base, iron (III) oxide, manganese oxide, Prussine Blue, and Paris Blue. The size of the pigment particles should not exceed the thickness of the layer containing the pigment. Most preferably, the particle size is no more than half the thickness of the layer. The amount of infrared absorber in the network structure of the crosslinked polymer is preferably an amount that gives an optical density of 0.05 or more, more preferably 0.5 to 3, in the network structure of the crosslinked polymer at the wavelength of the laser light. The content of the infrared absorber is preferably 0.01% by mass to 30% by mass, more preferably 0.05% by mass to 20% by mass, and particularly preferably 0.1% by mass to 10% by mass, relative to the total mass of the crosslinked polymer.

[0064] The photothermal conversion material can include a dye with an appropriate absorption spectrum and solubility. As the dye, dyes having a maximum absorption in the wavelength region of 750 nm to 1400 nm are particularly preferred. Examples of suitable dyes include dyes in the following classes: methine, polymethine, arylmethine, cyanine, hemicyanine, streptocyanine, squarylium, pyrylium, oxonol, naphthoquinone, anthraquinone, porphyrin, azo, croconium, triarylamine, thiazolium, indolium, oxazolium, indocyanine, indotricarbocyanine, oxatricarbocyanine, phthalocyanine, thiocyanine, thiatricarbocyanine, merocyanine, cryptocyanine, naphthalocyanine, polyaniline, polypyrrole, polythiophene, chalcogenopyriloarylidene, bis(chalcogenopyrilo)polymethine, oxiindolizine, pyrazolineazo, and oxazine.

[0065] Furthermore, when a water-soluble photothermal conversion material is used as the infrared absorber, the infrared absorber can be dissolved and decolorized when water is used as a solvent in the swelling step, which is preferable for use in non-coloring applications. The water-soluble photothermal conversion material preferably contains, for example, a cyanine dye having one or more sulfate or sulfonate groups.

[0066] Among these, preferred examples of the infrared absorber include cyanine dyes such as cyanine compounds, hemicyanine compounds, streptocyanine compounds, indocyanine compounds, indotricarbocyanine compounds, oxatricarbocyanine compounds, phthalocyanine compounds, thiocyanine compounds, thiatricarbocyanine compounds, merocyanine compounds, cryptocyanine compounds, and naphthalocyanine compounds, squarylium dyes, pyrylium salts, and nickel thiolate complexes, and more preferred examples of the infrared absorber include cyanine dyes.

[0067] "Process B2" In step B2, the crosslinked polymer after being irradiated with laser light in step A2 is impregnated with a solvent. As a result, the crosslinked polymer spontaneously bends due to the solvent impregnating more in the vicinity of the inner bottom surface 3a of the bent portion 3 formed in the crosslinked polymer than in the base portion of the crosslinked polymer (the portion not irradiated with laser light).

[0068] The solvent is not particularly limited, and examples thereof include water, organic solvents such as hexane, oils, and ionic liquids. However, from the viewpoint of inducing bending by swelling, it is preferable to use a solvent that is compatible with at least one type of polymer that forms the crosslinked polymer.

[0069] The thickness of the base before the solvent is impregnated is t1, and the thickness of the bent part before the solvent is impregnated is t s1In this case, the residual ratio (r) represented by the following formula (2) is preferably 0.01 or more and 1 or less, more preferably 0.05 or more and 0.8 or less, and even more preferably 0.1 or more and 0.6 or less. If the residual ratio (r) exceeds the upper limit, the damage to the network structure of the crosslinked polymer is small and bending cannot be achieved. If the residual ratio (r) is less than the lower limit, the bent portion swells evenly, and effective bending cannot be achieved. r=t s1 / t1(2)

[0070] According to the method for producing a molded article of the present disclosure, the molded article of the present disclosure can be obtained.

[0071] [Wearable devices] The wearable terminal of the present disclosure is a wearable terminal comprising a mounting body to be mounted on an adherend and an electronic device fixed to the mounting body, wherein the mounting body is made of the above-described molded article.

[0072] The wearable device of the present disclosure can be worn on an object such as the human body (wrist, arm, leg, torso, etc.), or an animal's limbs, neck, or torso.

[0073] The attachment is made of the above-mentioned molded article. Therefore, the attachment deforms to follow the shape of the adherend and adheres closely to the adherend. Furthermore, the attachment can memorize its shape by adjusting the swelling degree of the bent portion, so it adheres closely to the adherend even after repeated attachment and detachment from the adherend.

[0074] Examples of electronic devices include watches, smartphones, tablet terminals, and sensing devices.

[0075] The wearable device of the present disclosure can be firmly fixed to the adherend because the attachment body deforms to follow the shape of the adherend and fits tightly to the adherend. [Example]

[0076] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0077] [Example 1] A rectangular double-network gel (5 mm wide, 30 mm long, and 1.5 mm thick; first network: poly(2-acrylamido-2-methylpropanesulfonic acid), second network: polyacrylamide, containing pure water as the solvent) was synthesized by mixing the first network with pure water and irradiating it with UV light for 8 hours. The second network precursor solution was prepared by mixing the second network precursor with pure water and irradiating it with UV light for 8 hours. The first network was immersed in the second network precursor solution for 1 day, and the first network containing the second network precursor was then irradiated with UV light for 8 hours. A laser cutter (Universal Laser Systems) was used to irradiate the center of the double-network gel with a focused pulsed CO2 laser beam while scanning, forming a bent section. The focused laser beam generated high heat, which removed the surface of the double-network gel at the bent section. The depth of the surface removal (depth of the bent section) can be controlled by the laser pulse width, laser scanning speed, etc. The relative removal depth was defined as the residual rate (r) expressed by the following equation (2). r=t s1 / t1(2) In the above formula (2), t1 is the thickness of the part (base) other than the bent part, t s1 is the thickness of the bent part. Note that the thickness of the base t1 and the thickness of the bent part t s1 was measured before the solvent impregnation step was carried out. A double-network gel with a bent portion formed in the center using a laser cutter was immersed in pure water. The double-network gel then bent at the bent portion with the laser-irradiated surface facing outward. After the double-network gel had completely swelled, the bending angle θ of the bent portion was measured. The bending angle θ was determined by image analysis as the angle between the two bases adjacent to the bent portion. The results are shown in Figures 2 and 3. The results shown in Figure 2 indicate that the bending angle of the double network gel at the bent portion increases as the residual rate (r) decreases, that is, as the scraping depth of the double network gel increases. From the results shown in Figure 3, the length of the bent part, i.e., the cutting width L in the longitudinal direction of the double network gel, s It was found that the larger the bending angle of the double network gel at the bending section, the larger the bending angle. From the above results, it was found that the bending angle of the double network gel at the bent portion can be controlled by adjusting the cutting depth of the double network gel or the cutting width in the longitudinal direction of the double network gel.

[0078] [Example 2] The double-network gel of Example 1, and common single-network hydrogels, polydimethylacrylamide gel (crosslinker: N,N'-methylenebisacrylamide) and polyacrylamide gel (crosslinker: N,N'-methylenebisacrylamide), were used to perform laser cutting on each gel in the same manner as in Example 1 (all under the same conditions as in Example 1). Subsequently, each processed gel was immersed in pure water to swell, and the state of bending at the bent portion of each gel was observed. The results are shown in Figures 4 to 6. Figure 4 is a photograph showing the state of bending of a double-network gel. Figure 5 is a photograph showing the state of bending of a polydimethylacrylamide gel. Figure 6 is a photograph showing the state of bending of a polyacrylamide gel. As Figures 4 to 6 show, bending at the bent portion was observed in all gels, indicating that the present invention is applicable to the processing of various hydrogels. Furthermore, since the double-network gel bent the most, it was found that the present invention is particularly suitable for double-network gels. This is thought to be due to the influence of the unique network structure of the double-network gel (the rigid first network structure suppresses the swelling of the flexible second network structure).

[0079] [Example 3] A commercially available vulcanized styrene-butadiene rubber sheet was subjected to laser cutting in the same manner as in Example 1 (all under the same conditions as in Example 1). The processed vulcanized styrene-butadiene rubber sheet was then immersed in hexane to swell, and the state of bending at the bent portion of the vulcanized styrene-butadiene rubber sheet was observed. The results are shown in Figures 7 and 8. Figure 7 is a photograph showing the state of bending of the vulcanized styrene-butadiene rubber sheet when the residual ratio (r) is 0.3. Figure 8 is a photograph showing the state of bending of the vulcanized styrene-butadiene rubber sheet when the residual ratio (r) is 0.55. As Figures 7 and 8 show, bending at the bent portion was also observed in the vulcanized styrene-butadiene rubber sheet, indicating that the present invention is applicable to the processing of vulcanized styrene-butadiene rubber sheets.

[0080] [Example 4] A laser cutter can determine the cutting location with high resolution. When the double-network gel of Example 1 was subjected to laser cutting of various patterns and then immersed in pure water, it was possible to mold the gel into various shapes. The results are shown in Figures 9 to 12. Figure 9 is a photograph showing the double-network gel cut into a spiral shape. Note that the white areas in Figure 9 are the bent portions formed by the cutting process. Figure 10 is a photograph showing the double-network gel cut into a spiral shape and immersed in pure water. Figure 11 is a photograph showing the double-network gel cut into an unfolded box shape. Note that the white areas in Figure 11 are the bent portions formed by the cutting process. Figure 12 is a photograph showing the double-network gel cut into an unfolded box shape and immersed in pure water. As shown in Figure 10, when double-network gel cut into a spiral shape was immersed in pure water, the double-network gel bent into a spiral shape. As shown in Figure 12, when double-network gel cut into an unfolded box shape was immersed in pure water, the double-network gel folded into a box shape.

[0081] [Example 5] The swelling of the gel after laser cutting is thought to occur because the network structure contained in the crosslinked polymer near the laser-irradiated area (bent portion) is partially decomposed by heat, making the bent portion more susceptible to swelling in the solvent. The equilibrium swelling ratio of the network structure contained in the crosslinked polymer in the solvent is determined by the compatibility between the solvent and the crosslinked polymer. Therefore, we attempted to control the swelling ratio of the gel by changing the type of solvent, thereby reversibly controlling the shape. The gel folded into a box shape in Example 4 was immersed in a 50% by mass aqueous ethanol solution. Aqueous ethanol is a solvent that is not very compatible with double-network gels. The results are shown in Figure 13. As shown in Figure 13, the gel folded into a box shape was observed to open up as the solvent was removed and the swelling degree decreased. This demonstrates that the shape achieved by this invention can be reversibly controlled by changing the solvent conditions for swelling.

[0082] [Example 6] A double-network gel was prepared in the same manner as in Example 1, except that the polyacrylamide in the second network of the double-network gel in Example 1 was replaced with polydimethylacrylamide. Next, the gel was subjected to laser cutting (all under the same conditions as in Example 1). The processed gel was then immersed in pure water to swell, and the state of bending at the bent portion of the gel was observed. The results are shown in Figure 14. Figure 14 is a photograph showing the state of bending of the double-network gel. Bending was also observed at the laser-processed portion (bent portion) of this gel, and the bending of the double-network gel was more pronounced than that of the single-mesh hydrogel.

[0083] [Example 7] Poly N-isopropylacrylamide gel was prepared by dissolving N-isopropylacrylamide (monomer), N,N'-methylenebisacrylamide (crosslinker), potassium persulfate (polymerization initiator), and N,N,N',N'-tetramethylethylenediamine (polymerization accelerator) in pure water and allowing the solution to stand at 4°C for 12 hours. The gel was then subjected to laser cutting in the same manner as in Example 1 (all under the same conditions as in Example 1). It is known that poly N-isopropylacrylamide gels using pure water as the solvent become hydrophobic at temperatures above 32°C and exhibit a reduced swelling ratio. The processed gel was then immersed in pure water at 25°C to swell, and the state of bending at the bent portion of the gel was observed. The results are shown in Figure 15. Figure 15 is a photograph showing the state of bending of the poly-N-isopropylacrylamide gel. As in Example 2, bending at the bent portion was also observed in the poly-N-isopropylacrylamide gel. Next, the processed gel was immersed in pure water at 50°C for 24 hours, at which point the gel network becomes hydrophobic, and the state of bending at the bent portion was observed. The results are shown in Figure 16. Figure 16 is a photograph showing the state of bending of the poly-N-isopropylacrylamide gel. From Figure 16, a decrease in the bending angle was observed. Similarly to Example 1, the depth of the poly-N-isopropylacrylamide gel was adjusted to change the residual rate (r), and the bending angle was measured in pure water at 25°C and 50°C. The results are shown in Figure 17. Figure 17 shows the relationship between the bending angle of the bent portion and the residual rate. From Figure 17, it was found that at 25°C, the bending angle at the bent portion increased as the residual rate (r) decreased. On the other hand, at 50°C, the bending angle remained constant at around 0°, regardless of the residual rate (r). From the above results, it was found that the bending angle of the gel at the bending portion can be reversibly controlled by using a temperature-responsive gel. [Explanation of symbols]

[0084] 1. Molded body 2 base 3 Bend 3a Laser irradiation side of bent part 3b Opposite side of the bent part to the laser irradiation side

Claims

1. A molded body comprising a base and at least one bent portion connected to the base, the base portion and the bent portion are composed of a first crosslinked polymer having a first network structure and a second network structure; The thickness of the base before impregnation with the solvent is t １ The thickness of the base after the solvent is impregnated is t ２ The thickness of the bent portion before impregnation with the solvent is t ｓ１ The thickness of the bent portion after the solvent is impregnated is t ｓ２ The molded article has a swelling ratio (Q) represented by the following formula (1) of greater than 1 and not greater than 5 when expressed as: Q=(t ｓ２ / t ｓ１ ) / (t ２ / t １ ) (1) (However, t １ ≧t ｓ１ It is.)

2. A wearable terminal comprising: a mounting body to be mounted on an adherend; and an electronic device fixed to the mounting body, The wearable terminal, wherein the attachment body is the molded body according to claim 1.

3. A method for producing a molded article made of a crosslinked polymer and having a base and at least one bent portion connected to the base, comprising: a step of irradiating a laser beam to an arbitrary portion of the crosslinked polymer processed into a sheet or fiber; and impregnating the crosslinked polymer with a solvent after the laser beam irradiation.

4. The thickness of the base before impregnation with the solvent is t １ The thickness of the bent portion before impregnation with the solvent is t ｓ１ The method for producing a molded article according to claim 3, wherein the residual ratio (r) represented by the following formula (2) is 0.01 or more and 1 or less when the formula is: r=t ｓ１ / t １ (2)

5. The method for producing a molded article according to claim 3 , wherein the crosslinked polymer has an interpenetrating network structure or a semi-interpenetrating network structure.

6. The method for producing a molded article according to claim 3 , wherein the crosslinked polymer has an ultimate elongation network structure.

7. A method for producing a crosslinked polymer having an utmost stretch network structure, comprising: introducing a first monomer into the first network structure having a cross-linked structure, and polymerizing the first monomer to introduce a first molecular stent to form a second network structure; introducing a second monomer into the second network and polymerizing the second monomer to introduce a second molecular stent to form a third network; and introducing a third monomer into the third mesh structure, polymerizing the third monomer to introduce a third molecular stent, and forming a fourth mesh structure.

8. 8. The method for producing a crosslinked polymer according to claim 7, further comprising the step of immersing the fourth network structure in a solvent to swell the fourth network structure.

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