JP7460066B2 - Moisture absorbent - Google Patents

Description

The present invention relates to a moisture absorbent material.

Conventionally, deliquescent inorganic salts such as calcium chloride, magnesium chloride, and aluminum chloride have been used as hygroscopic materials. Although deliquescent inorganic salts have excellent hygroscopicity, they tend to liquefy after absorbing moisture, causing problems such as the liquid material leaking out and staining the surrounding area. As moisture absorbing materials that solve this problem, there are desiccant materials containing deliquescent inorganic salts and nonionic cellulose derivatives as gelling agents (see Patent Document 1), and dehumidifying materials made of deliquescent inorganic salts, hydrophilic polymers, and cellulose powder. Compositions (see Patent Document 2) and the like are known.

Japanese Patent Publication “Unexamined Japanese Patent Publication No. 2010-194497” Japanese Patent Publication “Unexamined Japanese Patent Publication No. 2000-5553”

However, while the above-mentioned conventional techniques can prevent leakage of the deliquescent liquid to some extent when it contains deliquescent inorganic salts, they are still insufficient in terms of hygroscopicity.

The present invention has been made in consideration of the above problems, and its purpose is to prevent leakage of the deliquescent liquid when it contains a deliquescent inorganic salt, while also realizing a moisture-absorbing material with excellent moisture absorption properties.

In order to solve the above-mentioned problems, a moisture absorbent according to one embodiment of the present invention is a moisture absorbent containing a moisture absorbent polymer material, which prevents leakage of a deliquescent liquid of a deliquescent inorganic salt, the moisture absorbent containing a hydrophilic polymer, and a ligand having an affinity for a monovalent, divalent, or trivalent metal ion constituting the deliquescent inorganic salt is bound to the moisture absorbent polymer material, the ligand being a host molecule forming an inclusion compound or a chelating agent, the host molecule being at least one type of molecule selected from the group consisting of crown compounds, cyclophanes, azacyclophanes, calixarenes, porphyrins, phthalocyanines, salens, and derivatives thereof, the chelating agent being at least one type of molecule selected from the group consisting of polyalkylene glycols, bipyridines, phenanthrolines, and derivatives thereof, the monovalent metal ion being Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , or Cs ⁺ , and the divalent metal ion being Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , or Ba ²⁺ , the trivalent metal ion is Al ³⁺ , Y ³⁺ , In ³⁺ , Sc ³⁺ , or a lanthanoid ion group, and the ligand captures the metal ion.

As described above, the moisture-absorbing material according to one embodiment of the present invention is a moisture-absorbing material containing a moisture-absorbing polymer material, and the moisture-absorbing polymer material contains a hydrophilic polymer and has a configuration in which a ligand having an affinity for monovalent, divalent, or trivalent metal ions is bonded to the moisture-absorbing polymer material. Therefore, it is possible to capture salts of the metal ions, which have high moisture absorption properties, and it is possible to prevent leakage of the deliquescent liquid derived from the salt and to realize a moisture-absorbing material with excellent moisture absorption properties.

It is a figure which shows the result of evaluating the moisture absorption behavior of the moisture absorption material in the Example of this invention. FIG. 2 is a diagram showing the results of evaluating the moisture absorption behavior of a moisture absorbent in an example of the present invention.

The following describes in detail the embodiments of the present invention. However, the present invention is not limited to these, and various modifications are possible within the scope described. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. In this specification, unless otherwise specified, "A to B" representing a numerical range means "A or more, B or less." Furthermore, "mass" and "weight" are considered to be synonymous. Furthermore, when referring to either "acrylic" or "methacrylic," the term "(meth)acrylic" is used.

[Embodiment 1: Moisture absorbent]
As a result of intensive research in consideration of the above-mentioned problems, the inventors have found that a moisture-absorbing material containing a hydrophilic polymer, in which a ligand having an affinity for monovalent, divalent, or trivalent metal ions is bound to the moisture-absorbing polymer material, is capable of capturing a salt of the metal ion with high moisture absorption properties, prevents leakage of deliquescent liquid derived from the salt, and realizes a moisture-absorbing material with excellent moisture absorption properties, thereby completing the present invention.

In other words, the moisture-absorbing material according to one embodiment of the present invention is a moisture-absorbing material containing a moisture-absorbing polymer material, the moisture-absorbing polymer material containing a hydrophilic polymer, and a ligand having an affinity for monovalent, divalent, or trivalent metal ions is bonded to the moisture-absorbing polymer material.

A hygroscopic material according to an embodiment of the present invention contains a hygroscopic polymeric material, and a ligand having an affinity for monovalent, divalent, or trivalent metal ions is bound to the hygroscopic polymeric material. ing. The ligand has an affinity for monovalent, divalent, or trivalent metal ions, and therefore can capture monovalent, divalent, or trivalent metal ions. Therefore, the salt of the metal ion having high hygroscopicity can be trapped in the hygroscopic polymeric material, and the hygroscopicity of the hygroscopic polymeric material can be increased. Conventional moisture absorption materials containing a deliquescent inorganic salt and a polymer as a gelling agent have been a mixture of a deliquescent inorganic salt and a polymer as a gelling agent. Compared to such conventional hygroscopic materials, the hygroscopic material according to one embodiment of the present invention has higher hygroscopicity. The reason for this is that by uniformly dispersing the ligand in the hygroscopic polymer material, the metal ion salt can be more uniformly dispersed, and therefore more efficient moisture absorption is possible. It is believed that there is.

In the present invention, the term "bond" in the description "ligand is bonded" is not limited to this, but is preferably bonded via a chemical bond such as a covalent bond, an ionic bond, or a coordinate bond, and is more preferably bonded via a covalent bond. This allows the ligand to be stably fixed within the hygroscopic polymer material. More specifically, the ligand can be suitably bonded to the hygroscopic polymer material by introducing a reactive functional group into the ligand and reacting the reactive functional group with the hygroscopic polymer material. Note that "bonded to the hygroscopic polymer material" means that the ligand is bonded to any polymer contained in the hygroscopic polymer material.

(I) Ligand having affinity for monovalent, divalent, or trivalent metal ions Examples of the monovalent metal ions include Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , etc. Can be done. Examples of the divalent metal ions include Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , and the like. Examples of the trivalent metal ions include Al ³⁺ , Y ³⁺ , In ³⁺ , Sc ³⁺ , lanthanoid ions, and the like.

In the moisture absorbent according to one embodiment of the present invention, the ligand is preferably a host molecule that forms an inclusion compound, a chelating agent, or a molecule having a functional group that forms an ionic bond with the metal ion. The host molecule can capture the metal ion by including the metal ion, the chelating agent can capture the metal ion by coordinating the metal ion, and the molecule having a functional group that forms an ionic bond with the metal ion can capture the metal ion by forming an ionic bond with the metal ion.

In one embodiment of the present invention, the host molecule is preferably at least one type of molecule selected from the group consisting of cyclodextrin, crown compounds, cyclophanes, azacyclophanes, calixarenes, porphyrins, phthalocyanines, salens, and derivatives thereof. These host molecules have a ring structure and can recognize and include a specific metal ion according to the size, volume, and shape of the inner hole of the ring structure. By including the metal ion in the hygroscopic polymer material, it is possible to capture a salt of the metal ion that has high hygroscopicity in the hygroscopic polymer material, thereby increasing the hygroscopicity of the hygroscopic polymer material.

The crown compounds are not particularly limited, but examples thereof include crown ethers, benzocrown ethers, dibenzocrown ethers, azacrown ethers, etc.

The crown ether is not particularly limited, but examples include 12-crown-4, 15-crown-5, 18-crown-6, and the like. In order to obtain a hygroscopic agent in which 15-crown-5 is bonded to the hygroscopic polymeric material, for example, 15-crown-5 having a reactive functional group that reacts with the hygroscopic polymeric material can be used. can. Examples of 15-crown-5 having a reactive functional group that reacts with a hygroscopic polymer material include 2-hydroxymethyl-15-crown-5, 2-aminomethyl-15-crown-5, 1-aza- Examples include 15-crown-5. Furthermore, in order to obtain a hygroscopic agent in which 18-crown-6 is bonded to the hygroscopic polymeric material, for example, 18-crown-6 having a reactive functional group that reacts with the hygroscopic polymeric material is used. be able to. Examples of the 18-crown-6 having a reactive functional group that reacts with a hygroscopic polymeric material include 2-hydroxymethyl-18-crown-6, 2-aminomethyl-18-crown-6, (+)- Examples include (18-crown-6)-2,11,12-tetracarboxylic acid and 1-aza-18-crown-6.

The benzo crown ether is not particularly limited, and examples thereof include benzo-18-crown-6, benzo-21-crown-7, benzo-24-crown-8, and the like.

Examples of the dibenzo crown ether include dibenzo-18-crown-6.

Examples of the azacrown ether include aza-12-crown-4, aza-15-crown-5, aza-18-crown-6, etc. Examples of the aza-15-crown-5 include 1-aza-15-crown-5, etc., which can be bound to the hygroscopic polymeric material. Examples of the aza-18-crown-6 include 1-aza-18-crown-6, etc., which can be bound to the hygroscopic polymeric material.

The crown compound is preferably selected and used as appropriate depending on the size of the metal ion to be captured. Specifically, for example, when including Li ions and Ca ions, the crown ether is preferably 15-crown-5 or aza-15-crown-5. Further, when K ions and Na ions are included, the crown ether is preferably 18-crown-6 or aza-18-crown-6.

In one embodiment of the moisture-absorbing material according to the present invention, the chelating agent is preferably at least one type of molecule selected from the group consisting of polyalkylene glycols such as polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetramethylene glycol, copolymers of ethylene glycol and propylene glycol, ethylenediamine, bipyridine, ethylenediaminetetraacetic acid, phenanthroline, and derivatives thereof.

In the moisture absorbent according to one embodiment of the present invention, the molecule having the functional group is preferably at least one type of molecule selected from the group consisting of carboxylic acid, phosphoric acid, sulfonic acid, and amines. Examples of such molecules include poly(meth)acrylic acid, polystyrene sulfonic acid, and polyallylamine.

It is preferable that the moisture absorbent material according to one embodiment of the present invention further contains a salt of a monovalent, divalent, or trivalent metal ion. Examples of the salt include, but are not limited to, lithium chloride, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, aluminum chloride, and the like. Among these, it is more preferable that the salt is a deliquescent salt. These salts may be used alone or in combination of two or more. When the hygroscopic material further contains a salt of the metal ion, the amount and rate of moisture absorption of the hygroscopic material can be improved.

(II) Hygroscopic polymer material In one embodiment of the present invention, the hygroscopic polymer material may contain a hydrophilic polymer. Examples of the hygroscopic polymer material include hydrophilic polymers, mixtures containing hydrophilic polymers, copolymers containing hydrophilic polymers, interpenetrating polymer networks containing hydrophilic polymers, and semi-interpenetrating polymer networks containing hydrophilic polymers. The hygroscopic polymer material can absorb moisture in the air by containing a hydrophilic polymer. The hygroscopic material according to one embodiment of the present invention contains the hygroscopic polymer material. That is, the hygroscopic material according to one embodiment of the present invention may be made of the hygroscopic polymer material, or may contain other components within a range that does not adversely affect the effects of the present invention.

In the hygroscopic material according to an embodiment of the present invention, it is more preferable that the hygroscopic polymeric material is one of the following (a) to (e).
(a) Hydrophilic polymer (b) A mixture of a stimulus-responsive polymer and a hydrophilic polymer whose affinity for water changes reversibly in response to an external stimulus (c) Water in response to an external stimulus Copolymer of a stimulus-responsive polymer and a hydrophilic polymer whose affinity for water reversibly changes (d) A stimulus-responsive polymer whose affinity for water reversibly changes in response to external stimuli (e) Semi-interpenetrating polymer network structure of a stimulus-responsive polymer and a hydrophilic polymer whose affinity for water reversibly changes in response to external stimuli Molecular network structure (hydrophilic polymer)
Examples of the hydrophilic polymer include polymers having a hydrophilic group such as a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, or an amino group in a side chain or main chain. More specific examples of the hydrophilic polymers include polysaccharides such as alginic acid and hyaluronic acid; chitosan; cellulose derivatives such as carboxymethylcellulose, methylcellulose, ethylcellulose, and hydroxyethylcellulose; poly(meth)acrylic acid and polymaleic acid. , polyvinylsulfonic acid, polyvinylbenzenesulfonic acid, polyacrylamide alkylsulfonic acid, polydimethylaminopropyl (meth)acrylamide, combinations of these with (meth)acrylamide, hydroxyethyl (meth)acrylate, (meth)acrylic acid alkyl ester, etc. Polymer, complex of polydimethylaminopropyl (meth)acrylamide and polyvinyl alcohol, complex of polyvinyl alcohol and poly(meth)acrylic acid, poly(meth)acrylonitrile, polyallylamine, polyvinyl alcohol, polyethylene glycol, polypropylene glycol , poly(meth)acrylamide, poly-N,N'-dimethyl(meth)acrylamide, poly-2-hydroxyethyl methacrylate, poly-alkyl(meth)acrylate, polydimethylaminopropyl(meth)acrylamide, poly(meth)acrylonitrile and copolymers of the above polymers. Moreover, it is more preferable that the hydrophilic polymer is a crosslinked product of these.

When the hydrophilic polymer is a crosslinked polymer, examples of such crosslinked polymers include polymers obtained by polymerizing monomers such as (meth)acrylic acid, allylamine, vinyl acetate, (meth)acrylamide, N,N'-dimethyl(meth)acrylamide, 2-hydroxyethyl methacrylate, alkyl(meth)acrylate, maleic acid, vinyl sulfonic acid, vinylbenzenesulfonic acid, acrylamidoalkylsulfonic acid, dimethylaminopropyl(meth)acrylamide, and (meth)acrylonitrile in the presence of a crosslinking agent.

As the crosslinking agent, conventionally known ones may be appropriately selected and used, and examples thereof include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, N,N'-methylenebis(meth)acrylamide, and tri-ethylene glycol di(meth)acrylate. Crosslinkable monomers with polymerizable functional groups such as diisocyanate, divinylbenzene, and polyethylene glycol di(meth)acrylate; glutaraldehyde; polyhydric alcohols; polyhydric amines; polycarboxylic acids; metals such as calcium ions and zinc ions Ions etc. can be suitably used. These crosslinking agents may be used alone or in combination of two or more.

(Stimulus-responsive polymers that reversibly change their affinity for water in response to external stimuli)
A stimuli-responsive polymer is a polymer that reversibly changes its properties in response to an external stimulus.

The external stimuli are not particularly limited, but may include, for example, heat, light, an electric field, pH, etc.

In addition, a reversible change in affinity for water in response to an external stimulus means that a polymer exposed to an external stimulus reversibly changes between hydrophilic and hydrophobic properties in response to the external stimulus.

Among them, stimulus-responsive polymers whose affinity for water reversibly changes in response to heat, that is, temperature-responsive polymers, can be used to increase the amount of water in the air by changing the temperature using a simple heating device. It can reversibly absorb moisture and release absorbed moisture. For this reason, temperature-responsive polymers can be particularly suitably used in humidity controllers.

Such a temperature-responsive polymer is not particularly limited as long as it has a lower critical solution temperature (LCST (Lower Critical Solution Temperature), hereinafter sometimes referred to as "LCST" in this specification). A polymer with an LCST is hydrophilic at low temperatures, but becomes hydrophobic at or above the LCST. Note that LCST here refers to the temperature at which, when a polymer is dissolved in water, it is hydrophilic and soluble in water at low temperatures, but becomes hydrophobic and insoluble at or above a certain temperature.

More specifically, the temperature-responsive polymer may be, for example, poly(N-alkyl(meth)acrylamides) such as poly(N-isopropyl(meth)acrylamide), poly(N-normal propyl(meth)acrylamide), poly(N-methyl(meth)acrylamide), poly(N-ethyl(meth)acrylamide), poly(N-normal butyl(meth)acrylamide), poly(N-isobutyl(meth)acrylamide), and poly(N-t-butyl(meth)acrylamide); poly(N-vinyl isopropylamide), poly(N-vinyl normal propylamide), poly(N-vinyl normal butylamide), poly(N-vinyl isobutylamide), and poly(N-vinyl-t-butyl(meth)acrylamide). Examples of suitable temperature-responsive polymers include poly(N-vinyl alkylamides) such as poly(N-vinylpyrrolidone); poly(2-alkyl-2-oxazolines) such as poly(2-ethyl-2-oxazoline), poly(2-isopropyl-2-oxazoline), and poly(2-normal propyl-2-oxazoline); polyvinyl alkyl ethers such as polyvinyl methyl ether and polyvinyl ethyl ether; copolymers of polyethylene oxide and polypropylene oxide; poly(oxyethylene vinyl ether); cellulose derivatives such as methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl methyl cellulose, and copolymers of the above polymers. When a cellulose derivative is used as the temperature-responsive polymer, it is easy to manufacture the moisture absorbent because no polymerization is required. In addition, cellulose derivatives have the advantage of being safe and biodegradable, and therefore have a small environmental impact. When hydroxypropyl cellulose is used as the cellulose derivative, the preferred average molecular weight of hydroxypropyl cellulose is 2,000 to 2,000,000, and the preferred degree of substitution is 1 to 3. It is more preferable that the temperature-responsive polymer is a crosslinked product of these polymers.

In one embodiment of the present invention, when the stimulus-responsive polymer and the hydrophilic polymer form an interpenetrating polymer network structure, both the stimulus-responsive polymer and the hydrophilic polymer are crosslinked. . In one embodiment of the present invention, when the stimulus-responsive polymer and the hydrophilic polymer form a semi-interpenetrating polymer network structure, either the stimulus-responsive polymer or the hydrophilic polymer is cross-linked. It is the body.

When the temperature-responsive polymer is a crosslinked product, examples of the crosslinked product include N-isopropyl(meth)acrylamide, N-normalpropyl(meth)acrylamide, N-methyl(meth)acrylamide, and N-ethyl(meth)acrylamide. ) Acrylamide, N-alkyl (meth)acrylamide such as N-normal butyl (meth)acrylamide, N-isobutyl (meth)acrylamide, N-t-butyl (meth)acrylamide; N-vinylisopropylamide, N-vinyl normal propyl N-vinyl alkylamides such as amide, N-vinyl normal butyramide, N-vinyl isobutyramide, and N-vinyl-t-butyramide; vinyl alkyl ethers such as vinyl methyl ether and vinyl ethyl ether; ethylene oxide and propylene oxide; 2 - Monomers such as 2-alkyl-2-oxazolines such as ethyl-2-oxazoline, 2-isopropyl-2-oxazoline, and 2-n-n-propyl-2-oxazoline, or two or more of these monomers, in the presence of a crosslinking agent. Polymers obtained by polymerization can be mentioned.

As the crosslinking agent, conventionally known ones may be appropriately selected and used, and examples thereof include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, N,N'-methylenebis(meth)acrylamide, and tri-ethylene glycol di(meth)acrylate. Crosslinkable monomers with polymerizable functional groups such as diisocyanate, divinylbenzene, and polyethylene glycol di(meth)acrylate; glutaraldehyde; polyhydric alcohols; polyhydric amines; polycarboxylic acids; metals such as calcium ions and zinc ions Ions etc. can be suitably used. These crosslinking agents may be used alone or in combination of two or more.

Alternatively, when the temperature-responsive polymer is a crosslinked product, such a crosslinked product can be formed by reacting a non-crosslinked temperature-responsive polymer, for example, the temperature-responsive polymer exemplified above, with the crosslinking agent to form a network structure. It may also be a crosslinked product obtained by forming.

Stimulus-responsive polymers whose affinity for water changes reversibly in response to light include photoresponsive polymers whose hydrophilicity or polarity changes in response to light, such as azobenzene derivatives and spiropyran derivatives; Examples include a copolymer with at least one of a responsive polymer and a pH-responsive polymer, a crosslinked product of the photoresponsive polymer, or a crosslinked product of the copolymer.

In addition, stimuli-responsive polymers whose affinity for water reversibly changes in response to an electric field include polymers with dissociative groups such as carboxyl groups, sulfonic acid groups, phosphoric acid groups, and amino groups; Examples include polymers formed into complexes by electrostatic interaction, hydrogen bonding, etc., such as a complex between a polymer containing a polymer and an amino group-containing polymer, or crosslinked products thereof.

Examples of stimuli-responsive polymers whose affinity for water changes reversibly in response to pH include polymers having dissociable groups such as carboxyl groups, sulfonic acid groups, phosphate groups, and amino groups, polymers that form complexes through electrostatic interactions or hydrogen bonds, such as complexes between carboxyl group-containing polymers and amino group-containing polymers, and crosslinked products of these.

Although the molecular weight of the stimulus-responsive polymer is not particularly limited, it is preferable that the number average molecular weight determined by gel permeation chromatography (GPC) is 3000 or more.

((a): Hydrophilic polymer)
As the hygroscopic polymer material, the aforementioned hydrophilic polymers may be used alone, or two or more of the aforementioned hydrophilic polymers may be used as a mixture. In such cases, a ligand that has an affinity for monovalent, divalent, or trivalent metal ions is bound to a hydrophilic polymer.

The hydrophilic polymer is itself hydrophilic and can absorb moisture in the air. In addition, the ligand is bound to the hydrophilic polymer, so that the hydrophilic polymer can capture the highly hygroscopic salt of the metal ion, thereby enhancing the hygroscopicity of the hygroscopic polymer material. Furthermore, compared to the case where the salt of the metal ion is simply mixed with a hydrophilic polymer that does not contain the ligand, the salt of the metal ion can be uniformly dispersed by uniformly dispersing the ligand, thereby enhancing the hygroscopicity.

The effect due to the ligand binding to the hydrophilic polymer is an effect that can be obtained with any hygroscopic polymer material containing a hydrophilic polymer. Therefore, similar effects can be obtained in cases (b) to (e) described below.

((b): A mixture of a stimulus-responsive polymer and a hydrophilic polymer whose affinity for water reversibly changes in response to external stimuli)
The hygroscopic polymer material may include a stimulus-responsive polymer or a mixture of two or more types of stimulus-responsive polymers whose affinity for water reversibly changes in response to the external stimulus described above, and the aforementioned ( Mixtures with a) can be used. In such a case, a ligand having an affinity for monovalent, divalent, or trivalent metal ions is bound to at least one of the stimulus-responsive polymer and the hydrophilic polymer.

By using the mixture, the hygroscopic polymer material can reversibly absorb moisture in the air and release the absorbed moisture by changing the temperature, for example, using a simple heating device, due to the property of the stimuli-responsive polymer that reversibly changes its affinity for water in response to an external stimulus. In addition, since the ligand is bound to the hygroscopic polymer material, the salt of the metal ion, which has high hygroscopicity, can be captured, and the hygroscopicity of the hygroscopic polymer material can be increased. Furthermore, compared to the case where the salt of the metal ion is simply mixed with a hygroscopic polymer material that does not contain the ligand, the salt of the metal ion can be uniformly dispersed by uniformly dispersing the ligand, thereby increasing the hygroscopicity.

In addition, when the salt of the metal ion is simply mixed with a hygroscopic polymer material that does not contain the ligand, there is a problem that when the hygroscopic polymer material containing a stimuli-responsive polymer releases the moisture absorbed, the salt of the metal ion leaks out along with the released moisture. The leakage of the salt of the metal ion causes the hygroscopicity of the hygroscopic material to decrease while repeatedly absorbing moisture in the air and releasing the absorbed moisture. In contrast, since the ligand is bound to the hygroscopic polymer material, the ligand holds the metal ion, so that the salt of the metal ion can be prevented from leaking out along with the released water. In addition, since the donor potential barrier is maintained even though the metal ion is ionized in the hygroscopic polymer material, the leakage of the salt of the metal ion can be effectively suppressed.

The above-mentioned effect due to the inclusion of a stimuli-responsive polymer in the hygroscopic polymer material is an effect that can be obtained in any hygroscopic polymer material that includes a stimuli-responsive polymer. Therefore, the same effect can be obtained in the cases (c) to (e) described below.

The ratio of the stimuli-responsive polymer to the hydrophilic polymer contained in the hygroscopic polymer material is not particularly limited, but the hydrophilic polymer is more preferably contained in an amount of 5% by weight or more, even more preferably 20% by weight or more, and even more preferably 1000% by weight or less, and even more preferably 700% by weight or less, relative to the stimuli-responsive polymer, in terms of weight ratio excluding the weight of the crosslinking agent.

((c): Copolymer of stimulus-responsive polymer and hydrophilic polymer whose affinity for water reversibly changes in response to external stimuli)
The hygroscopic polymer material may include a stimulus-responsive polymer or a mixture of two or more types of stimulus-responsive polymers whose affinity for water reversibly changes in response to the external stimulus described above, and the aforementioned ( Copolymers with a) can be used. In such a case, a ligand having an affinity for monovalent, divalent, or trivalent metal ions is bound to at least one of the stimulus-responsive polymer and the hydrophilic polymer. Note that the copolymer herein is not particularly limited as long as it is a polymer containing a structural unit constituting a stimulus-responsive polymer and a structural unit constituting a hydrophilic polymer.

Although the ratio of the structural units constituting the stimulus-responsive polymer and the structural units constituting the hydrophilic polymer to the total constitutional units contained in the hygroscopic polymeric material is not particularly limited, With respect to the structural units forming the stimulus-responsive polymer, the structural units forming the hydrophilic polymer are more preferably contained in an amount of 30 mol% or more, still more preferably 40 mol% or more, and more preferably The content is preferably 80 mol% or less, more preferably 50 mol% or less.

((d): Interpenetrating polymer network structure of a stimulus-responsive polymer and a hydrophilic polymer whose affinity for water reversibly changes in response to external stimuli)
As the hygroscopic polymer material, an interpenetrating polymer network structure of the above-mentioned stimulus-responsive polymer or a mixture of two or more kinds of stimulus-responsive polymers and the above-mentioned (a) can be used. Here, an interpenetrating polymer network structure is one in which different types of polymers are all crosslinked polymers, and the crosslinked networks of each polymer exist independently without being chemically bonded to each other. It refers to an intertwined structure. That is, the interpenetrating polymer network structure is such that the hydrophilic polymer and the stimulus-responsive polymer are both crosslinked polymers, and the crosslinked network of the hydrophilic polymer and the stimulus-responsive polymer are crosslinked polymers. It refers to a structure in which crosslinked polymer networks are intertwined with each other in a state where they exist independently without being chemically bonded. When the hydrophilic polymer or the stimulus-responsive polymer is a mixture, at least one hydrophilic polymer and the stimulus-responsive polymer in the mixture may form an interpenetrating polymer network structure. Bye. By using the interpenetrating polymer network structure, the affinity for water increases in response to an external stimulus, compared to when a mixture or copolymer of the hydrophilic polymer and the stimulus-responsive polymer is used. Changes are more clearly reversible. Therefore, by applying an external stimulus, moisture in the air can be absorbed and the absorbed moisture can be released more efficiently, so that it can be particularly suitably used in a humidity conditioner.

The ratio of the stimuli-responsive polymer to the hydrophilic polymer contained in the hygroscopic polymer material is not particularly limited, but the hydrophilic polymer is more preferably contained in an amount of 5% by weight or more, even more preferably 20% by weight or more, and even more preferably 1000% by weight or less, and even more preferably 700% by weight or less, relative to the stimuli-responsive polymer, in terms of weight ratio excluding the weight of the crosslinking agent.

((e): Semi-interpenetrating polymer network structure of a stimulus-responsive polymer and a hydrophilic polymer whose affinity for water reversibly changes in response to external stimuli)
As the hygroscopic polymer material, a semi-interpenetrating polymer network structure of the above-mentioned stimulus-responsive polymer or a mixture of two or more types of stimulus-responsive polymers and the above-mentioned (a) can be used. . Here, a semi-interpenetrating polymer network structure is one in which one of different types of polymers is a crosslinked polymer and the other is a linear polymer or a non-crosslinked polymer, and each polymer is chemically Structures that are intertwined with each other and exist independently without being combined. That is, the semi-interpenetrating polymer network structure of the above-mentioned stimulus-responsive polymer or a mixture of two or more types of stimulus-responsive polymers and the hydrophilic polymer is defined as One of the polymers is a crosslinked polymer and the other is a non-crosslinked polymer, and the stimulus-responsive polymer and the hydrophilic polymer exist independently without being chemically bonded. A structure that is intertwined with each other. When the hydrophilic polymer or the stimulus-responsive polymer is a mixture, at least one hydrophilic polymer and the stimulus-responsive polymer in the mixture form a semi-interpenetrating polymer network structure. That's fine. By using the semi-interpenetrating polymer network structure, the affinity for water in response to an external stimulus is higher than when using a mixture or copolymer of the hydrophilic polymer and the stimulus-responsive polymer. changes more clearly and reversibly. Therefore, by applying an external stimulus, moisture in the air can be absorbed and the absorbed moisture can be released more efficiently, so that it can be particularly suitably used in a humidity conditioner.

The ratio of the stimulus-responsive polymer to the hydrophilic polymer contained in the hygroscopic polymer material is not particularly limited, but the ratio of the stimulus-responsive polymer to the hydrophilic polymer, excluding the weight of the crosslinking agent, The content of the hydrophilic polymer is more preferably 5% by weight or more, even more preferably 20% by weight or more, and even more preferably 1000% by weight or less, still more preferably 700% by weight or less. Contains less than % by weight.

(III) Moisture absorbent In the moisture absorbent according to one embodiment of the present invention, the ratio of the ligand contained in the moisture absorbent polymer material to the total structural units of the polymer contained in the moisture absorbent polymer material is preferably 10 mol% to 80 mol%, more preferably 30 mol% to 80 mol%, and even more preferably 40 mol% to 70 mol%. If the ratio of the ligand is 40 mol% or more, the ratio of metal ions contained in the moisture absorbent material is also high, which is preferable because the moisture absorption is improved. If the ratio of the ligand is 70 mol% or less, it is preferable because it does not affect the release of absorbed moisture when the stimuli-responsive polymer is used. Here, "contained in the moisture absorbent polymer material" means that it is present in the moisture absorbent polymer material, regardless of whether it is bound to the moisture absorbent polymer material.

In the hygroscopic material according to one embodiment of the present invention, at least a portion of the ligand is bonded to the hygroscopic polymer material. The ratio of the ligand bonded to the hygroscopic polymer material to the total structural units of the polymer contained in the hygroscopic polymer material is more preferably 10 mol% to 80 mol%, and 40 mol%. % to 70 mol % is more preferable. If the proportion of the ligand is 40 mol % or more, the proportion of metal ions contained in the moisture absorbent material will also be high, which improves the hygroscopicity, which is preferable. It is preferable that the proportion of the ligand is 70 mol % or less, since this does not affect the release of absorbed water when the stimulus-responsive polymer is used.

The shape of the moisture absorbent material according to one embodiment of the present invention is not particularly limited, and may be plate-like, sheet-like, film-like, or particle-like. The shape of the particulate moisture absorbent material is not particularly limited either, but may be, for example, approximately spherical, plate-like, or the like. Further, the size of the moisture absorbing material according to the present invention is not particularly limited, and when used in a humidity controller, it may be appropriately selected depending on the configuration of the humidity controller.

The hygroscopic polymer material is preferably a dried body dried by, for example, reduced pressure (vacuum) drying, heat drying, natural drying, or a combination thereof, and more preferably a dried body dried by reduced pressure drying or heat drying. By reduced pressure drying or heat drying, the hygroscopic polymer material can form fine holes when the solvent used in polymerization is sublimated and released to the outside, forming a dried body of the hygroscopic polymer material having a dense mesh structure. The hygroscopic polymer material having a dense mesh structure has a large area in contact with the air, so that the proportion of the amount of moisture absorbed in the air is high. In addition, the hygroscopic polymer material having a dense mesh structure can suppress leakage of the salt of the metal ion due to the close entanglement of the molecular chains. Furthermore, the hygroscopic polymer material having a dense mesh structure can maintain an equilibrium state after the salt of the metal ion is released with the release of water, because the functional groups of the hygroscopic polymer material that are not bound to the ligands maintain electrical neutrality in the hygroscopic polymer material, whether it is absorbing moisture in the air or releasing water due to a stimulus such as heating.

The degree of reduced pressure in the case of drying by the reduced pressure drying is preferably 10 Pa to 100 Pa, more preferably 20 Pa to 50 Pa.

It is more preferable that the vacuum drying is freeze-drying, which is performed after freezing the hygroscopic polymer material. By drying the hygroscopic polymer material under reduced pressure after freezing, the hygroscopic polymer material produces fine pores when the solvent used for polymerization sublimes and exits to the outside, and the hygroscopic polymer material has a dense network structure. A dry body of the polymeric material can be formed. The freezing temperature is preferably -60°C to -20°C, more preferably -60°C to -30°C. Although the drying time depends on the amount of sample, it is preferably 20 hours or more, more preferably 30 hours or more. The upper limit of the drying time is preferably about 50 hours.

In one embodiment of the present invention, the dry body of the hygroscopic polymeric material does not need to have moisture completely removed from the hygroscopic polymeric material, but as long as it can absorb moisture in the air, May contain. Therefore, the moisture content of the dry body of the hygroscopic polymeric material is not particularly limited as long as the dry body can absorb moisture in the air, but is, for example, 10% to 30% by weight. It is preferably 20% to 25% by weight, more preferably 20% to 25% by weight. Note that the moisture content herein refers to the ratio of moisture to the dry weight of the hygroscopic polymer material.

The above explanation of the dried body relates to hygroscopic polymeric materials, but the same applies to hygroscopic materials.

[Embodiment 2: Method for manufacturing moisture absorbent material]
A method for producing a hygroscopic material according to an embodiment of the present invention is a hygroscopic material containing a hygroscopic polymeric material, wherein the hygroscopic polymeric material contains a hydrophilic polymer, and the hygroscopic polymeric material contains a hydrophilic polymer. This is a method for producing a moisture absorbent material in which a ligand having an affinity for monovalent, divalent, or trivalent metal ions is bound to the material.

In one embodiment of the present invention, a method for producing a hygroscopic material includes a hygroscopic polymeric material containing a hydrophilic polymer, wherein monovalent, divalent, or trivalent metal ions are added to the hygroscopic polymeric material. A hygroscopic polymeric material manufacturing step for manufacturing a hygroscopic polymeric material to which a ligand having an affinity is bound, and a drying step for drying the hygroscopic polymeric material obtained in the hygroscopic polymeric material manufacturing step. It is sufficient if it includes at least the following. Furthermore, the method may include a pulverizing step of pulverizing the hygroscopic polymer material dried in the drying step.

Below, we will explain each step that constitutes the manufacturing method of the moisture-absorbent material according to one embodiment of the present invention. However, we will omit the explanation of the contents that overlap with the contents explained in the moisture-absorbent material mentioned above.

(Hygroscopic polymer material manufacturing process)
The hygroscopic polymer material manufacturing process is not particularly limited as long as it is a process that can manufacture the hygroscopic polymer material, but the hygroscopic polymer material can be manufactured, for example, by the following method. be able to.

[1] A step (i) of reacting a monomer constituting the hydrophilic polymer with the ligand to bond at least a portion of the ligand to the monomer constituting the hydrophilic polymer; A method comprising a step (ii) of polymerizing the monomer to which the ligand is bound obtained in step i).

[2] Step (i) of synthesizing the hydrophilic polymer by polymerizing monomers constituting the hydrophilic polymer or preparing the commercially available hydrophilic polymer; A method comprising the step (ii) of reacting with the ligand to bind at least a portion of the ligand to the hydrophilic polymer.

[3] Step (i) of reacting the monomer constituting the stimulus-responsive polymer with the ligand to bind at least a portion of the ligand to the monomer constituting the stimulus-responsive polymer; a step (ii) of synthesizing the stimulus-responsive polymer to which the ligand is bound by polymerizing the monomer to which the ligand is bound obtained in step (i); and step (ii) A method comprising a step (iii) of mixing the stimulus-responsive polymer obtained in [1] or [2] with the hydrophilic polymer obtained by the method [2].

[4] A method comprising the steps of: (i) synthesizing the stimuli-responsive polymer by polymerizing monomers constituting the stimuli-responsive polymer, or preparing a commercially available stimuli-responsive polymer; (ii) reacting the stimuli-responsive polymer with the ligand to bind at least a portion of the ligand to the stimuli-responsive polymer, thereby obtaining the stimuli-responsive polymer to which the ligand is bound; and (iii) mixing the stimuli-responsive polymer obtained in the step (ii) with a hydrophilic polymer obtained by the method of [1] or [2].

[5] The monomers constituting the hydrophilic polymer, the monomers constituting the stimulus-responsive polymer, and the ligand are reacted to convert at least a portion of the ligand into monomers constituting the hydrophilic polymer and/or or a step (i) of respectively bonding the monomers constituting the stimulus-responsive polymer, and the monomers constituting the hydrophilic polymer and the monomers constituting the stimulus-responsive polymer obtained in step (i). A method comprising a step (ii) of copolymerizing.

[6] A method comprising: a step (i) of copolymerizing a monomer constituting the hydrophilic polymer with a monomer constituting the stimuli-responsive polymer to obtain a copolymer; and a step (ii) of reacting the copolymer obtained in the step (i) with the ligand to bind at least a portion of the ligand to the copolymer.

[7] Step (i) of reacting a monomer constituting the stimulus-responsive polymer with the ligand to bind at least a portion of the ligand to the monomer constituting the stimulus-responsive polymer; and the step Step (ii) of forming a crosslinked network (a) of the crosslinked product of the stimulus-responsive polymer by polymerizing and crosslinking the monomers forming the stimulus-responsive polymer obtained in (i);
a step (iii) of reacting a monomer constituting the hydrophilic polymer with the ligand to bond at least a portion of the ligand to the monomer constituting the hydrophilic polymer; By polymerizing and crosslinking the monomers constituting the hydrophilic polymer obtained in step (iii) in the presence of the hydrophilic polymer, a crosslinked network (a) and a crosslinked network ( b) and step (iv) of forming an interpenetrating polymer network structure.

[8] Step (i) of forming a crosslinked network (a) of a crosslinked product of the stimulus-responsive polymer by polymerizing and crosslinking monomers constituting the stimulus-responsive polymer;
By polymerizing and crosslinking the monomers constituting the hydrophilic polymer in the presence of the crosslinked network (a), a crosslinked network (b) of the crosslinked product of the hydrophilic polymer is formed from the crosslinked network (a) and the crosslinked network (b) of the crosslinked product of the hydrophilic polymer. Step (ii) of forming an interpenetrating polymer network structure, and reacting the hygroscopic polymer material obtained in step (ii) and forming the interpenetrating polymer network structure with the ligand, (iii) binding at least a portion of the ligand to the hygroscopic polymeric material.

[9] A process (i) of reacting a monomer constituting the stimuli-responsive polymer with the ligand to bond at least a part of the ligand to the monomer constituting the stimuli-responsive polymer, and a process (ii) of polymerizing and crosslinking the monomer constituting the stimuli-responsive polymer obtained in the process (i) to form a crosslinked network (a) of the crosslinked body of the stimuli-responsive polymer;
The method includes the steps of: (iii) reacting a monomer constituting the hydrophilic polymer with the ligand to bond at least a portion of the ligand to the monomer constituting the hydrophilic polymer; and (iv) polymerizing the monomer constituting the hydrophilic polymer obtained in the step (iii) in the presence of a crosslinked network (a) to form a semi-interpenetrating polymer network structure composed of the crosslinked network (a) and a non-crosslinked hydrophilic polymer.

[10] Step (i) of forming a crosslinked network (a) of a crosslinked product of the stimulus-responsive polymer by polymerizing and crosslinking monomers constituting the stimulus-responsive polymer;
By polymerizing monomers constituting the hydrophilic polymer in the presence of the crosslinked network (a), a semi-interpenetrating polymer network structure consisting of the crosslinked network (a) and the non-crosslinked hydrophilic polymer is obtained. and reacting the hygroscopic polymer material obtained in step (ii) and forming the semi-interpenetrating polymer network structure with the ligand to form at least a portion of the ligand. (iii) of bonding the hygroscopic polymeric material to the hygroscopic polymeric material.

[11] A step (i) of reacting a monomer constituting the stimulus-responsive polymer with the ligand and binding at least a portion of the ligand to the monomer constituting the stimulus-responsive polymer; step (ii) of producing the non-crosslinked stimulus-responsive polymer by polymerizing the monomers forming the stimulus-responsive polymer obtained in i);
a step (iii) of reacting a monomer constituting the hydrophilic polymer with the ligand to bond at least a portion of the ligand to the monomer constituting the hydrophilic polymer; and a step (iii) of the non-crosslinking stimulus response. By polymerizing and crosslinking the monomers constituting the hydrophilic polymer obtained in step (ii) in the presence of the hydrophilic polymer, the non-crosslinked stimuli-responsive polymer and the hydrophilic polymer are combined. (iv) forming a semi-interpenetrating polymeric network structure consisting of a crosslinked network (b) of crosslinked molecules.

[12] Step (i) of producing the non-crosslinked stimulus-responsive polymer by polymerizing monomers constituting the stimulus-responsive polymer;
By polymerizing and crosslinking monomers constituting the hydrophilic polymer in the presence of the non-crosslinked stimulus-responsive polymer obtained in step (i), the non-crosslinked stimulus-responsive polymer and a step (ii) of forming a semi-interpenetrating polymer network structure consisting of a crosslinked network (b) of the crosslinked product of the hydrophilic polymer, and the semi-interpenetrating polymer network obtained in the step (ii). A method comprising the step (iii) of reacting the structured hygroscopic polymeric material with the ligand to bind at least a portion of the ligand to the hygroscopic polymeric material.

In the methods [3] and [4] above, a hydrophilic polymer to which the ligand is bound and a stimuli-responsive polymer to which the ligand is bound are mixed, but either the hydrophilic polymer or the stimuli-responsive polymer may be one to which the ligand is not bound.

In addition, in the method of [7], an interpenetrating polymer network structure is formed between the hydrophilic polymer to which the ligand is bound and the stimuli-responsive polymer to which the ligand is bound, but either the hydrophilic polymer or the stimuli-responsive polymer may be one to which the ligand is not bound.

In the above methods [1] to [12], the polymerization method for polymerizing the monomer is not particularly limited, and radical polymerization, ionic polymerization, polycondensation, ring-opening polymerization, etc. can be suitably used. The solvent used in the polymerization can also be appropriately selected depending on the monomer, and for example, water, phosphate buffer, Tris buffer, acetate buffer, methanol, ethanol, etc. can be suitably used.

The polymerization initiator is not particularly limited, and examples thereof include persulfates such as ammonium persulfate and sodium persulfate; hydrogen peroxide; peroxides such as t-butyl hydroperoxide and cumene hydroperoxide; Isobutyronitrile, benzoyl peroxide, and the like can be suitably used. Among these polymerization initiators, initiators showing oxidizing properties such as persulfates and peroxides are particularly suitable for combinations with sodium bisulfite, N,N,N',N'-tetramethylethylenediamine, etc. It can also be used as a redox initiator. Alternatively, light, radiation, etc. may be used as an initiator.

The polymerization temperature is not particularly limited, but is usually 5°C to 80°C. The polymerization time is not particularly limited, but is usually 4 hours to 48 hours.

The concentrations of the monomer, crosslinking agent, etc. during polymerization are not particularly limited as long as they are concentrations that can produce the stimuli-responsive polymer, the hydrophilic polymer, or crosslinked products thereof. The concentration of the polymerization initiator is also not particularly limited and may be selected appropriately.

In the methods [7] to [12] above, the method of forming a crosslinked network of the stimulus-responsive polymer or the crosslinked product of the hydrophilic polymer by polymerizing and crosslinking monomers refers to It may be a method of polymerizing in the presence of a polymer, or a method of polymerizing monomers to form a polymer and then crosslinking with a crosslinking agent.

In step (iv) of the above [7], [9] and [11], polymerization conditions or crosslinking conditions may be appropriately selected so that crosslinking is not formed between the polymer or its crosslinked product formed in step (ii). In step (iii) of the above [8], [10] and [12], polymerization conditions or crosslinking conditions may be appropriately selected so that crosslinking is not formed between the polymer or its crosslinked product formed in step (i).

In the methods [1] to [12] above, the monomers constituting the stimulus-responsive polymer, the monomers constituting the hydrophilic polymer, and the crosslinking agent are as described in (I) above.

In addition, in the methods [7] to [12] above, when the stimuli-responsive polymer or the hydrophilic polymer is, from the beginning, a polymer such as a cellulose derivative or a polysaccharide, "polymerizing and crosslinking the monomers constituting the stimuli-responsive polymer" shall be read as "crosslinking the stimuli-responsive polymer," and "polymerizing and crosslinking the monomers constituting the hydrophilic polymer" shall be read as "crosslinking the hydrophilic polymer."

In addition, in the methods [7] to [12] above, after producing the stimulus-responsive polymer or a crosslinked product thereof, the hydrophilic polymer is After producing the hydrophilic polymer or the crosslinked product, in the presence of the obtained hydrophilic polymer or the crosslinked product, the stimulus-responsive polymer is produced. Molecules or crosslinks thereof may also be produced.

Further, in the methods [7] to [12], the interpenetrating polymer network structure or the semi-interpenetrating polymer network structure is obtained after producing the stimulus-responsive polymer or its crosslinked product. The hydrophilic polymer or its crosslinked product is produced in a two-step process in the presence of the stimulus-responsive polymer or its crosslinked product, and the stimulus-responsive polymer or its crosslinked product is If the hydrophilic polymer or its crosslinked product is polymerized or crosslinked by selecting polymerization conditions or crosslinking conditions such that no crosslink is formed between the stimulus-responsive polymer or its crosslinked product and the hydrophilic polymer or its crosslinked product. , can also be performed simultaneously in one step. For example, if a combination is used in which the polymerization method and crosslinking agent used to produce the hydrophilic polymer or its crosslinked product are different from the polymerization method and crosslinking agent used to produce the hydrophilic polymer or its crosslinked product, , the hygroscopic polymeric material can be manufactured in a one-step process.

(Drying process)
In the drying step, the hygroscopic polymer material obtained in the hygroscopic polymer material production step is dried to obtain a dried body of the hygroscopic polymer material.

The method for drying the hygroscopic polymer material is not particularly limited, and any conventionally known method can be used as appropriate. Examples of methods for drying the hygroscopic polymer material include drying by heating, drying under reduced pressure, freeze-drying, and solvent replacement.

(Crushing process)
The dried body of the hygroscopic polymer material obtained by the drying step is pulverized in the pulverizing step, if necessary.

The method of grinding is not particularly limited, but for example, the dried body of the moisture-absorbing polymer material can be ground using a mechanical grinder such as a rotor, a ball mill, an airflow grinder, etc., and further classified as necessary to obtain a particulate moisture absorbent.

Further, the particulate hygroscopic material can also be manufactured by synthesizing fine particles of hygroscopic polymeric material using emulsion polymerization in the hygroscopic polymeric material manufacturing process.

[Embodiment 3: Humidity controller]
The hygroscopic material according to the present invention, particularly the hygroscopic material containing the hydrophilic polymer and the stimulus-responsive polymer, can absorb moisture in the air and release the absorbed moisture reversibly, so it can be used in a humidity conditioner. It can be used particularly preferably, and a humidity controller using the moisture absorbing material can efficiently control humidity without supercooling or using a large amount of heat. Therefore, the present invention also includes a humidity controller using a moisture absorbent material according to an embodiment of the present invention. Hereinafter, a humidity controller according to an embodiment of the present invention will be described. A humidity controller according to an embodiment of the present invention is a hygroscopic material containing a hygroscopic polymer material, the hygroscopic polymer material containing a hydrophilic polymer and a stimulus-responsive polymer, and the hygroscopic material containing a hygroscopic polymer material. A hygroscopic material in which a ligand having an affinity for monovalent, divalent, or trivalent metal ions is bound to a hygroscopic polymer material, and for reducing the affinity of the stimulus-responsive polymer with water. and a stimulation applying section that applies an external stimulation. Here, it is preferable that the moisture absorbent material further contains a salt of a monovalent, divalent, or trivalent metal ion. Regarding the moisture absorbing material, descriptions of the same contents as those described in [Embodiment 1] will be omitted.

The humidity conditioner according to one embodiment of the present invention is provided with a humidity conditioner body having an intake port and an exhaust port. Inside the humidity conditioner body, there are provided a plurality of humidity conditioner units carrying the moisture-absorbing material of the present invention, a humidity conditioner area in which the humidity conditioner units absorb moisture in the air, a dehydration area in which the moisture conditioner units absorb moisture in the air and release the absorbed moisture as water, a drainage tank for storing the released water, and a blower fan for taking in the air to be absorbed through the intake port and discharging the absorbed air through the exhaust port. In this embodiment, the humidity conditioner is a humidity conditioner containing a moisture-absorbing polymer material, which contains a hydrophilic polymer and a stimuli-responsive polymer whose affinity with water changes reversibly in response to an external stimulus, and a ligand having an affinity for monovalent, divalent, or trivalent metal ions is bonded to the moisture-absorbing polymer material.

The plurality of humidity control units are movable between the humidity control area and the dehydration area. The dehydration area is provided with a stimulus applying section that applies an external stimulus to reduce the affinity of the stimulus-responsive polymer with water. When the stimulus-responsive polymer is, for example, a temperature-responsive polymer, the stimulus applying section is, for example, a heater.

The air (humid air) taken into the humidity control machine comes into contact with the moisture absorbing material of the humidity control unit when passing through the humidity control area. Moisture-absorbing materials that are hydrophilic at room temperature absorb moisture in the air (humid air), thereby absorbing moisture from the humid air as it passes through the humidity control area, and discharging the absorbed air (dry air) through the exhaust outlet. is exhausted from.

The humidity control unit that has absorbed moisture in the air (humid air) moves from the humidity control area to the dehydration area. In the humidity control unit that has been moved to the dehydration area within the dehydration area, an external stimulus is applied to the hygroscopic material by the stimulation applying section, so that the hygroscopic material becomes hydrophobic. As a result, the moisture absorbed by the hygroscopic material is released from the hygroscopic material as water. The released water is then drained into a drainage tank.

At this time, in the humidity conditioner according to an embodiment of the present invention, since the ligand is bonded to the hygroscopic polymer material of the moisture absorbing material, the ligand holds the metal ion, so that the metal ion is released. It is possible to prevent the salt of the metal ion from leaking out together with water. Therefore, even when the humidity control unit repeatedly moves between the humidity control area and the dehydration area, the absorption of moisture in the air by the moisture absorbing material and the release of the absorbed moisture are repeated. A decrease in the hygroscopicity of the hygroscopic material can be suppressed.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Furthermore, new technical features can be formed by combining the technical means disclosed in the respective embodiments.

〔summary〕
The hygroscopic material according to aspect 1 of the present invention is a hygroscopic material containing a hygroscopic polymeric material, wherein the hygroscopic polymeric material contains a hydrophilic polymer, and the hygroscopic polymeric material contains 1 It has a structure in which a ligand having an affinity for a valent, divalent, or trivalent metal ion is bound.

According to the above configuration, it is possible to capture the salt of the metal ion, which has high hygroscopicity, thereby preventing leakage of the deliquescent liquid derived from the salt and realizing a hygroscopic material with excellent hygroscopicity.

A moisture absorbent material according to Aspect 2 of the present invention has a structure in which the ligand is a host molecule forming an clathrate compound, a chelating agent, or a molecule having a functional group that ionically bonds with the metal ion. We are prepared.

According to the above configuration, the salt of the metal ion having high hygroscopicity can be captured in the hygroscopic polymer material, and the hygroscopicity of the hygroscopic polymer material can be increased.

In the moisture absorbing material according to aspect 3 of the present invention, in the above aspect 2, the host molecule is a group consisting of cyclodextrin, crown compound, cyclophane, azacyclophane, calixarene, porphyrin, phthalocyanine, salen, and derivatives thereof. The composition includes at least one type of molecule selected from the following.

According to the above configuration, the salt of the metal ion having high hygroscopicity can be captured in the hygroscopic polymer material, and the hygroscopicity of the hygroscopic polymer material can be increased.

In the moisture absorbing material according to Aspect 4 of the present invention, in Aspect 2, the chelating agent is at least one selected from the group consisting of polyalkylene glycol, ethylenediamine, bipyridine, ethylenediaminetetraacetic acid, phenanthroline, and derivatives thereof. It has a composition that is a molecule of.

According to the above configuration, the salt of the metal ion, which has high hygroscopicity, can be captured in the hygroscopic polymer material, thereby increasing the hygroscopicity of the hygroscopic polymer material.

The moisture-absorbing material of aspect 5 of the present invention has a configuration similar to that of aspect 2 above, in which the molecule having the functional group is at least one type of molecule selected from the group consisting of carboxylic acids, phosphoric acids, sulfonic acids, and amines.

According to the above configuration, the salt of the metal ion, which has high hygroscopicity, can be captured in the hygroscopic polymer material, thereby increasing the hygroscopicity of the hygroscopic polymer material.

A hygroscopic material according to aspect 6 of the present invention has a configuration in which the hygroscopic polymer material has any of the following (a) to (e) in any one of aspects 1 to 5 above.
(a) Hydrophilic polymer (b) A mixture of a stimulus-responsive polymer and a hydrophilic polymer whose affinity for water changes reversibly in response to an external stimulus (c) Water in response to an external stimulus Copolymer of a stimulus-responsive polymer and a hydrophilic polymer whose affinity for water reversibly changes (d) A stimulus-responsive polymer whose affinity for water reversibly changes in response to external stimuli (e) Semi-interpenetrating polymer network structure of a stimulus-responsive polymer and a hydrophilic polymer whose affinity for water reversibly changes in response to external stimuli Molecular Network Structure According to the above configuration (a), the hydrophilic polymer is hydrophilic in itself and can absorb moisture in the air, and in addition to the fact that the ligand is bonded to the hydrophilic polymer, The salt of the metal ion having high hygroscopicity can be captured, and the hygroscopicity of the hygroscopic polymer material can be increased. Furthermore, even when compared to simply mixing the salt of the metal ion using a hydrophilic polymer that does not contain the ligand, it is possible to uniformly disperse the salt of the metal ion by uniformly dispersing the ligand. As a result, hygroscopicity can be increased.

According to the above configurations (b) to (e), in addition, when the salt of the metal ion is simply mixed with a stimuli-responsive polymer that does not contain the ligand, there is a problem that when the stimuli-responsive polymer releases the moisture absorbed by the polymer, the salt of the metal ion leaks out along with the released moisture. The leakage of the salt of the metal ion causes the moisture absorption of the moisture absorbent to decrease as the absorbent repeatedly absorbs moisture from the air and releases the absorbed moisture. In contrast, by binding the ligand to the stimuli-responsive polymer, the ligand holds the metal ion, so that it is possible to prevent the salt of the metal ion from leaking out along with the released water.

The hygroscopic material according to Aspect 7 of the present invention is characterized in that, in any one of Aspects 1 to 6 above, the amount of the ligand bonded to the hygroscopic polymer material relative to the total structural unit of the polymer contained in the hygroscopic polymer material is The proportion is comprised between 10 mol% and 80 mol%.

The above structure is preferable because it improves the hygroscopicity of the hygroscopic material, and when the stimulus-responsive polymer is used, it is preferable because it does not affect the release of absorbed moisture.

The moisture-absorbing material according to aspect 8 of the present invention has a configuration in which, in any one of aspects 1 to 7 above, it further contains a salt of a monovalent, divalent, or trivalent metal ion.

The above configuration is preferable because the hygroscopicity of the hygroscopic material is improved.

[Examples 1 to 3, Comparative Example 1]
Example 1: Synthesis of Alg-PEG(CaCl ₂ /LiCl)/HPC semi-interpenetrating polymer network
100 mg of sodium alginate (Alg) and 10 wt % polyethylene glycol diglycidyl ether (PEGDE) based on Alg were dissolved in 100 ml of ultrapure water. The resulting aqueous solution was heated at 70° C. for 11 hours. The heated aqueous solution was mixed with an aqueous solution of hydroxypropyl cellulose (HPC) (an aqueous solution obtained by dissolving HPC (Wako Pure Chemical Industries, Ltd., hydroxypropyl cellulose 150-400 cP)) in 100 ml of ultrapure water). 200 ml of an aqueous solution of CaCl ₂ /LiCl, each having a concentration of 0.5 M, was added to the resulting mixture and allowed to stand for 24 hours to obtain a polymer gel (Alg-PEG (CaCl ₂ /LiCl)/HPC semi-interpenetrating polymer network structure) in which CaCl ₂ /LiCl was captured in the semi-interpenetrating polymer network structure of alginic acid bound to polyethylene glycol (PEG) and HPC. The obtained polymer gel was frozen at -30°C and dried for 36 hours under reduced pressure of 20 Pa to obtain a dried polymer gel (moisture absorbent 1) in which CaCl ₂ /LiCl was trapped in the Alg-PEG/HPC semi-interpenetrating polymer network structure. The ratio of the ligand to the total structural units of the polymer contained in moisture absorbent 1 was approximately 5 mol %.

<Example 2>
CaCl ₂ /LiCl was added to the Alg-PEG/HPC semi-interpenetrating polymer network structure in the same manner as in Example 1, except that the amount of PEGDE added to sodium alginate (Alg) was 20 wt% with respect to Alg. A dried polymer gel (hygroscopic material 2) in which was captured was obtained. The ratio of the ligand to the total structural units of the polymer contained in the moisture absorbent material 2 was about 10 mol%.

Example 3
A dried polymer gel (moisture absorbent 3) was obtained in which CaCl ₂ /LiCl was trapped in the Alg-PEG/HPC semi-interpenetrating polymer network structure in the same manner as in Example 1, except that the amount of PEGDE added to sodium alginate (Alg) was 30 wt % relative to Alg. The ratio of the ligand to the total structural units of the polymer contained in moisture absorbent 3 was about 15 mol %.

Comparative Example 1: Synthesis of Alg/HPC semi-interpenetrating polymer network structure
A mixture of a dried Alg/HPC semi-interpenetrating polymer network structure and CaCl ₂ /LiCl (comparative moisture absorbent 1) was obtained in the same manner as in Example 1, except that the amount of PEGDE added to sodium alginate (Alg) was 0.

<Moisture absorption behavior of Alg/HPC semi-interpenetrating polymer network structure and Alg-PEG (CaCl ₂ /LiCl)/HPC semi-interpenetrating polymer network structure>
Hygroscopic materials 1 to 3 and comparative hygroscopic material 1 were left to stand under constant temperature and humidity conditions of a temperature of 25° C. and a humidity of 80% RH, and their moisture absorption behavior was investigated by measuring changes in weight over time.

Figure 1 shows the moisture absorption rate versus time. In Figure 1, the vertical axis shows the moisture content (labeled "Amount of moisture absorption" in Figure 1. In other words, moisture content is the amount of moisture absorbed in the air. Unit: g/g-dried polymer (labeled "g/g-dried polymer" in Figure 1)), and the horizontal axis shows time (unit: hours). As shown in Figure 1, the higher the proportion of PEG bound to Alg, the higher the moisture absorption rate. This is because a larger amount of PEG also results in a larger amount of coordinated Ca ions and Li ions.

[Example 4, Comparative Example 2]
Example 4: Synthesis of Alg-CE (CaCl ₂ /LiCl)
1 g of sodium alginate (Alg) was dissolved in 100 ml of ultrapure water. In order to react 50 mol% of the carboxyl groups in Alg to the obtained Alg aqueous solution, 735 mg of ethylene dichloride (EDC) and 437 mg of N-hydroxysuccinimide (NHS) were added and stirred for 30 minutes to prepare an EDC/NHS-activated Alg aqueous solution. Next, a CE aqueous solution in which 690 mg of 2-aminomethyl-15-crown-5 (CE) was dissolved in 10 ml of ultrapure water was dropped into the EDC/NHS-activated Alg aqueous solution and stirred for 8 hours to obtain an aqueous solution containing Alg-CE. The aqueous solution containing Alg-CE was purified by dialyzing it against ultrapure water using a cellulose dialysis membrane and removing small molecules less than the molecular weight cutoff in the solution by passive diffusion. Thereafter, the purified Alg-CE was dissolved in ultrapure water to prepare an Alg-CE aqueous solution. 200 ml of a 0.5 M CaCl ₂ /LiCl aqueous solution was added to the Alg-CE aqueous solution and allowed to stand for 20 hours to obtain a polymer gel (Alg-CE(CaCl ₂ /LiCl)) in which CaCl ₂ /LiCl was captured by alginic acid bound to CE. The obtained polymer gel was frozen at -30°C and dried under reduced pressure of 20 Pa for 36 hours to obtain a dried body (moisture absorbent 4). The ratio of the ligand to the total structural units of the polymer contained in moisture absorbent 4 was approximately 50 mol %.

<Comparative Example 2>
1 g of sodium alginate (Alg) was dissolved in 100 ml of ultrapure water. 200 ml of a CaCl ₂ /LiCl aqueous solution, each with a concentration of 0.5 M, was added to the resulting Alg aqueous solution and allowed to stand for 30 hours to obtain a polymer gel that was a mixture of Alg and CaCl ₂ /LiCl. The resulting polymer gel was frozen at -30°C and dried under reduced pressure conditions of 20 Pa for 36 hours to obtain a dried polymer gel that was a mixture of Alg and CaCl ₂ /LiCl (comparative moisture absorbent 2).

<Moisture absorption behavior of Alg and Alg-CE (CaCl ₂ /LiCl)>
Moisture absorption behavior of Moisture Absorbent Material 4 and Comparative Moisture Absorption Material 2 was studied by allowing them to stand under constant temperature and humidity conditions of 25° C. and humidity of 80% RH, and measuring changes in weight over time.

Figure 2 shows moisture absorption rate versus time. In Figure 2, the vertical axis shows moisture content (labeled "Amount of moisture absorption" in Figure 2. In other words, moisture content is the amount of moisture absorbed in the air. Unit: g/g-dried polymer (labeled "g/g-dried polymer" in Figure 2)), and the horizontal axis shows time (unit: hours). As shown in Figure 2, moisture absorbent 4, in which CE is bound to Alg, has a higher moisture absorption rate than comparative moisture absorbent 2, in which CE is not bound to Alg. This is because CE encapsulates Ca ions and Li ions.

The hygroscopic material according to the present invention is very useful as a hygroscopic/dehydrating material and can be suitably used in a humidity controller.

Claims (4)

A hygroscopic material containing a hygroscopic polymeric material,
The moisture absorbing material is a moisture absorbing material that prevents leakage of deliquescent liquid of the deliquescent inorganic salt,
The hygroscopic polymer material contains a hydrophilic polymer,
A ligand having an affinity for monovalent, divalent, or trivalent metal ions constituting the deliquescent inorganic salt is bound to the hygroscopic polymer material,
The ligand is a host molecule that forms an inclusion compound or a chelating agent,
The host molecule is at least one type of molecule selected from the group consisting of crown compounds, cyclophanes, azacyclophanes, calixarenes, porphyrins, phthalocyanines, salens, and derivatives thereof,
The chelating agent is at least one molecule selected from the group consisting of polyalkylene glycol, bipyridine, phenanthroline, and derivatives thereof,
The monovalent metal ion is Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , or Cs ⁺ ,
The divalent metal ion is Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , or Ba ²⁺ ,
The moisture absorbent material, wherein the trivalent metal ion is Al ³⁺ , Y ³⁺ , In ³⁺ , Sc ³⁺ , or a lanthanoid ion group, and the ligand captures the metal ion. 2. The moisture-absorbing material according to claim 1, wherein the moisture-absorbing polymer material is any one of the following (a) to (e).
(a) a hydrophilic polymer; (b) a mixture of a stimuli-responsive polymer, the affinity for water of which reversibly changes in response to an external stimulus, and a hydrophilic polymer; (c) a copolymer of a stimuli-responsive polymer, the affinity for water of which reversibly changes in response to an external stimulus, and a hydrophilic polymer; (d) an interpenetrating polymer network structure of a stimuli-responsive polymer, the affinity for water of which reversibly changes in response to an external stimulus, and a hydrophilic polymer; (e) a semi-interpenetrating polymer network structure of a stimuli-responsive polymer, the affinity for water of which reversibly changes in response to an external stimulus, and a hydrophilic polymer. The moisture-absorbing material according to claim 1 or 2, characterized in that the ratio of the ligand contained in the moisture-absorbing polymer material to the total polymer structural units contained in the moisture-absorbing polymer material is 10 mol % to 80 mol %. 4. The moisture absorbent according to claim 1 , further comprising the deliquescent inorganic salt .

Images