Polymer composition with moisture absorption and desorption, and humidity control material

Abstract

To provide a polymer composition that achieves both excellent moisture absorption and dispersion amount and moisture absorption and dispersion speed, and does not accompany odor, furthermore a humidity control material, an aqueous dispersion, a crosslinking precursor and its solution, a film-like polymer composition or a bulky polymer composition, a humidity control material, which use the polymer composition.SOLUTION: A polymer composition comprises a polymer containing 1.0 to 20.0 mmol / g of carboxyl groups, a monocarboxylic acid having at least one hydroxyl group and a molecular weight of 80 to 1000, and an inorganic cation. A polymer composition comprises a polymer containing 1.0 to 20.0 mmol / g of carboxyl groups, a polycarboxylic acid with a molecular weight of 100 to 1000, and an inorganic cation. It is preferable that the solubility in water at 25°C of the organic acid salt composed of the aforesaid monocarboxylic acid or polycarboxylic acid and the inorganic cation is 1 to 200 g / 100 mL.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polymer composition having moisture absorbing and releasing properties, and a humidity-conditioning material using the polymer composition. [Background technology]

[0002] Conventional moisture absorption elements and adsorption heat pumps used to dehumidify air containing water vapor have used a variety of moisture absorption materials, such as activated carbon, silica gel, zeolite, and polymer adsorbents, but there have been several issues depending on the type of material selected. For example, inorganic materials such as silica gel and zeolite have problems such as insufficient moisture absorption capacity and the high regeneration temperature required to desorb moisture. To solve these problems, some zeolites (product name: FAM-Z02 (manufactured by Mitsubishi Chemical Corporation)) have been developed with low regeneration temperatures, but the amount of water vapor sorption is still insufficient.

[0003] On the other hand, polymeric sorbents such as polyacrylates and polystyrene sulfonates are used as moisture absorbents (see Non-Patent Document 1 and Patent Document 1). These materials have a relatively high moisture absorption capacity, and the regeneration temperature required to desorb moisture tends to be lower than that of inorganic materials, but they have the problem of insufficient adsorption and regeneration speeds during moisture adsorption and desorption. As mentioned above, at present, it is extremely difficult to synthesize a moisture-absorbing material that has both excellent moisture absorption capacity and moisture absorption speed.

[0004] On the other hand, the performance of an adsorption heat cycle is determined by how fast and large the amount of moisture absorption and desorption can be achieved, i.e., by the amount and rate of moisture absorption and desorption, so there are limitations to the performance of adsorption heat cycles using existing moisture absorbents as described above. For this reason, the current performance of adsorption heat cycles makes it difficult to miniaturize the equipment, and their widespread adoption in society is lagging. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-011320 [Non-patent literature]

[0006] [Non-Patent Document 1] Kiyoshi Saito and 22 others, "Basic Theory and Latest Technology of Desiccant Air Conditioning Systems," 1st ed., S&T Publishing, September 2015, pp. 75-83. Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a polymer composition that exhibits both an excellent moisture absorption amount and an excellent moisture absorption rate. It is also an object of the present invention to provide a polymer composition that exhibits both an excellent moisture absorption and desorption amount and an excellent moisture absorption and desorption rate. It is also an object of the present invention to provide a humidity-conditioning material, an aqueous dispersion, a crosslinkable precursor and a solution thereof, a film-shaped polymerization composition or a bulk polymerization composition, and a humidity-conditioning member that use this polymer composition. Among polymer compositions that combine excellent moisture absorption and desorption amounts and rates, there are also polymer compositions that have an odor. If there were no odor-related constraints, it would be easy to provide polymer compositions that combine excellent moisture absorption and desorption amounts and rates. However, polymer compositions that have an odor are not suitable for use in the atmosphere, and are particularly difficult to use in environments where people live or work. Therefore, a further object of the present invention is to provide a polymer composition that has both an excellent moisture absorption and desorption amount and a high moisture absorption and desorption rate and is odorless, and to provide a humidity-conditioning material, an aqueous slurry or dispersion, a crosslinkable precursor and a solution thereof, a film-like polymerization composition or bulk polymerization composition, a humidity-conditioning element, and a heat exchange element using the polymer composition. [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by using a polymer composition containing a specific carboxylic acid and a specific inorganic cation, and have arrived at the present invention. That is, the gist of the present invention is as follows. [1] A polymer composition comprising: a polymer containing 1.0 to 20.0 mmol / g of a carboxy group; a monocarboxylic acid having at least one hydroxy group and a molecular weight of 80 to 1000; and an inorganic cation. [2] The polymer composition according to [1], wherein the organic acid salt formed from the monocarboxylic acid and the inorganic cation has a solubility in water at 25°C of 1 to 200 g / 100 mL. [3] A polymer composition comprising a polymer containing 1.0 to 20.0 mmol / g of carboxy groups, a polycarboxylic acid having a molecular weight of 100 to 1000, and an inorganic cation. [4] The polymer composition according to [3], wherein the organic acid salt formed from the polycarboxylic acid and the inorganic cation has a solubility in water at 25°C of 1 to 200 g / 100 mL. [5] The polymer composition according to [3] or [4], wherein the polycarboxylic acid has a molecular weight of 200 to 1,000. [6] The polymer composition according to any one of [1] to [5], wherein the inorganic cation includes one or more selected from the group consisting of Mg, Ca, Cu, and Zn. [7] The polymer composition according to any one of [1] to [6], which has a lower critical solution temperature in water of 0 to 80°C. [8] A humidity-conditioning material comprising the polymer composition according to any one of [1] to [7], which is in the form of particles and has a median particle size of 0.01 to 1000 μm. [9] The humidity-conditioning material according to [8], further comprising inorganic particles.

[10] The humidity-conditioning material according to [8] or [9], wherein the content of the polymer composition is 20% by mass or more.

[0009]

[11] An aqueous slurry or aqueous dispersion containing the humidity-conditioning material according to any one of [8] to

[10] .

[12] A crosslinkable precursor, wherein a polymer obtained by crosslinking any crosslinkable precursor contains 20% by mass or more of the polymer composition according to any one of [1] to [7].

[13] A crosslinkable precursor containing 20% ​​by mass or more of the polymer composition according to any one of [1] to [7].

[14] A crosslinkable precursor solution in which the crosslinkable precursor according to

[12] or

[13] is diluted with a solvent.

[15] A film-like polymerization composition or bulk polymerization composition obtained by photocrosslinking or thermal crosslinking the crosslinkable precursor according to

[12] or

[13] .

[16] A humidity-conditioning member in which the polymer composition according to any one of [1] to [7] is bound to a nonwoven fabric directly or via a binder.

[17] A humidity control member in which the humidity control material according to any one of [8] to

[10] is bound to a nonwoven fabric directly or via a binder.

[18] A humidity-conditioning member in which the crosslinkable precursor according to

[12] or

[13] is bound to a nonwoven fabric directly or via a binder.

[19] A heat exchange element in which the polymer composition according to any one of [1] to [7] and a refrigerant containing at least water are in contact with a part of a heat exchanger directly or via a binder. [Effects of the Invention]

[0010] The polymer composition of the present invention has both an excellent moisture absorption and desorption amount and a high moisture absorption and desorption rate, and is odorless, so that it has a small environmental impact and is suitable as a humidity-conditioning material to be used in environments where people live or work. The humidity-conditioning material, aqueous slurry or aqueous dispersion, crosslinkable precursor and solution thereof, film-shaped polymerization composition or bulk polymerization composition, humidity-conditioning member, and heat exchange member of the present invention have both excellent moisture absorption and desorption amounts and moisture absorption and desorption rates, and are odorless. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing an example of a water vapor adsorption isotherm in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be practiced with various modifications within the scope of the gist thereof. The numerical ranges of the contents and content ratios, various physical property values, and property values ​​disclosed in this specification can be arbitrarily combined with their lower and upper limits to form new numerical ranges. The following definitions of terms are used herein: "(Meth)acrylic" is a general term for "acrylic" and "methacrylic". "(Meth)acrylate" is a general term for "acrylate" and "methacrylate." A numerical range expressed by "to" means a numerical range that includes the numbers before and after "to" as the lower and upper limits. For example, "A to B" is synonymous with A or more and B or less.

[0013] [Polymer composition] The polymer composition of the first aspect of the present invention is a polymer composition comprising a polymer containing 1.0 to 20.0 mmol / g of carboxy groups, a monocarboxylic acid having at least one hydroxy group and a molecular weight of 80 to 1000, and an inorganic cation. The polymer composition according to the second aspect of the present invention is a polymer composition comprising a polymer containing 1.0 to 20.0 mmol / g of carboxy groups, a polycarboxylic acid having a molecular weight of 100 to 1000, and an inorganic cation.

[0014] "First Aspect" The polymer composition of the first embodiment will be described below.

[0015] <Polymer> The polymer used in the first embodiment is a polymer containing 1.0 to 20.0 mmol / g of carboxy groups, and is a polymer containing 1.0 to 20.0 mmol / g of carboxy groups per dry resin weight. In the present invention, a polymer containing 1.0 to 20.0 mmol / g of carboxy groups is also referred to as a "polymer compound."

[0016] Examples of polymers include acrylic polymers and styrene polymers, among which acrylic polymers are preferred because they are easy to introduce carboxyl groups and other reactive functional groups into. The polymer may be either crosslinked or non-crosslinked, but the crosslinked type is preferred since it is possible to suppress excessive swelling when absorbing moisture.

[0017] The content of carboxy groups in the dry resin is 1.0 to 20.0 mmol / g, preferably 3.0 to 20.0 mmol / g, and more preferably 8.0 to 20.0 mmol / g. When the content of carboxyl groups is equal to or greater than the lower limit, the moisture absorption amount is sufficient and the effects of the present invention are exhibited. When the content of carboxyl groups is equal to or less than the upper limit, the introduction of functional groups is appropriate and there are fewer constraints on synthesis.

[0018] The weight average molecular weight (Mw) of the polymer is preferably from 1,000 to 1,000,000, more preferably from 10,000 to 1,000,000, and even more preferably from 100,000 to 1,000,000. When the weight-average molecular weight of the polymer is equal to or greater than the lower limit, the polymer composition can easily maintain its shape as a solid, and elution of the polymer can be reduced when the polymer composition is used, for example, as a humidity control member or heat exchange member, as described below. When the weight-average molecular weight of the polymer is equal to or less than the upper limit, the polymer composition can sufficiently ensure the plasticity and flexibility required for post-processing when used, for example, as a humidity control member or heat exchange member, as described below. The weight average molecular weight of a polymer refers to the weight average molecular weight measured by gel permeation chromatography (GPC) and converted into standard polystyrene.

[0019] The polymer can be obtained, for example, by copolymerizing a monomer having a carboxy group with a monomer not having a carboxy group. That is, the polymer can be, for example, a polymer (resin) having a constitutional unit derived from a monomer having a carboxy group and a constitutional unit derived from a monomer not having a carboxy group.

[0020] Examples of the monomer having a carboxy group include (meth)acrylic acid, itaconic acid, crotonic acid, maleic acid, and fumaric acid. Of these, (meth)acrylic acid is preferred. Examples of the monomer not having a carboxy group include linear or branched alkyl group-containing (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and dodecyl (meth)acrylate; alicyclic (meth)acrylates such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate; and 2-hydroxyethyl (Meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and other hydroxy group-containing (meth)acrylates; glycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, and other epoxy group-containing (meth)acrylates; dimethyl acrylate Amino group-containing (meth)acrylates such as aminoethyl (meth)acrylate and diethylaminoethyl (meth)acrylate; amide group-containing (meth)acrylates such as (meth)acrylamide, N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-propyl (meth)acrylamide, Nn-butyl (meth)acrylamide, N-isopropyl acrylamide, hydroxyethyl acrylamide, N-methoxymethyl (meth)acrylamide, and N-butoxymethyl (meth)acrylamide; aromatic compounds such as styrene and α-methylstyrene. vinyl; unsaturated nitriles such as (meth)acrylonitrile; vinyl ethers such as methyl vinyl ether and butyl vinyl ether; vinyl halides such as vinyl chloride and vinyl bromide; vinylidene halides such as vinylidene chloride and vinylidene bromide; aliphatic or alicyclic crosslinkable unsaturated monomers having two or more allyl or vinyl groups, such as 1,5-hexadiene, 2-methyl-1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene, 1,5-cyclooctadiene, and 1,2,4-trivinylcyclohexane;Examples of the aromatic crosslinkable polyunsaturated monomer include divinylbenzene, divinyltoluene, divinylxylene, and divinylnaphthalene. These monomers may be used alone or in combination of two or more.

[0021] Alternatively, the polymer may be a resin produced by a synthesis method for a weakly acidic cation exchange resin as described in Japanese Patent No. 3376637 or by a synthesis method for a polyacrylic acid-based superabsorbent resin. In particular, the polymer is preferably a weakly acidic cation exchange resin.

[0022] Examples of weakly acidic cation exchange resins include (meth)acrylic acid-based weakly acidic cation exchange resins that have weakly acidic groups such as carboxyl groups as exchange groups. The counter ions of the carboxyl groups are hydrogen ions (H + ), metal ions (e.g., Na + etc.), ammonium ion (NH4 + ) and other cations. The weakly acidic cation exchange resin can be obtained, for example, by polymerizing a monomer component containing the above-mentioned monomer having a carboxy group. If necessary, the obtained polymer can be hydrolyzed to form the weakly acidic cation exchange resin. That is, the weakly acidic cation exchange resin can be a polymer obtained by polymerizing a monomer component containing a monomer having a carboxy group or a hydrolyzate thereof. The monomer component may further contain the above-mentioned monomer not having a carboxy group. A preferred combination of monomers is, for example, a combination of an unsaturated nitrile, a linear or branched alkyl group-containing (meth)acrylate, an aliphatic or alicyclic crosslinkable unsaturated monomer having two or more allyl or vinyl groups, and an aromatic crosslinkable polyunsaturated monomer. The polymer obtained by polymerizing these monomers is also particularly called an "acrylonitrile-based crosslinked copolymer."

[0023] The polymerization method is not particularly limited, but examples thereof include suspension polymerization, dispersion polymerization, and emulsion polymerization. In particular, it is preferable to carry out the polymerization in a suspension state in an aqueous medium mainly composed of water. The polymerization of the monomer components may be carried out in the presence of an inert organic solvent, preferably one having a specific gravity of 1.0 or more, such as halogenated hydrocarbons such as carbon tetrachloride, dichloroethane, dichloropropane, trichloroethane, trichloropropane, chlorobenzene, dichlorobenzene, chloroxylene, bromoethane, dibromoethane, and bromobenzene. The hydrolysis method is not particularly limited, but examples thereof include a method in which hydrolysis is carried out in the presence of an acid such as sulfuric acid or hydrochloric acid, or an alkali such as sodium hydroxide or potassium hydroxide.

[0024] The polymer may be a synthetic product or a commercially available product. Examples of commercially available polymer products include "Relite WK60L" manufactured by Mitsubishi Chemical Corporation; "C104Plus," "C106," "C107E," and "C115E" manufactured by Purolite; and "AMBERLITE HPR8400 H" and "AMBERLITE IRC76" manufactured by Organo Corporation. The polymers may be used alone or in combination of two or more.

[0025] <Monocarboxylic acid> The monocarboxylic acid used in the first embodiment is a monocarboxylic acid having at least one hydroxy group and a molecular weight of 80 to 1,000. Monocarboxylic acids have both hydrophilic groups, hydroxyl groups and carboxyl groups, in the molecule, and can produce odorless polymer compositions.

[0026] The number of hydroxy groups that a monocarboxylic acid has is at least 1. There is no particular upper limit to the number of hydroxy groups, but since this is the upper limit of the number of hydroxy groups that the molecule can have, the number of hydroxy groups is generally preferably 6 or less. If the number of hydroxy groups is one or more, the compound has a high boiling point and does not have an unpleasant odor like acetic acid or propionic acid, making it suitable for use in the atmosphere.

[0027] The molecular weight of the monocarboxylic acid is 80 to 1000, preferably 100 to 1000, and more preferably 150 to 500, from the viewpoints of solubility in water and ion exchange reactivity. If the molecular weight is 80 or more, the polymer will not be separated from the base polymer in an aqueous solution, and there is little possibility of unintentional diffusion into the atmosphere, making it suitable for use in the atmosphere. If the molecular weight is 1000 or less, the water solubility required during synthesis is sufficient, and the reaction rate does not decrease.

[0028] Examples of monocarboxylic acids include lactic acid, hydroxybutyric acid, and 3-hydroxy-3-methylbutyric acid. Among these, 3-hydroxy-3-methylbutyric acid is preferred from the viewpoints of solubility and material stability. The monocarboxylic acids may be used alone or in combination of two or more.

[0029] <Inorganic cation> The inorganic cation used in the first embodiment is not particularly limited as long as it can form an organic acid salt described below with the monocarboxylic acid. However, it preferably contains a cation of one or more metal atoms selected from the group consisting of Li, Na, K, Mg, Ca, Cu, Zn, and Fe, and more preferably contains a cation of one or more metal atoms selected from the group consisting of Mg, Ca, Cu, and Zn, because this easily changes the hydrophilicity / hydrophobicity of the resulting polymer composition, allows the polymer composition to have a large amount of water vapor absorption / desorption performance at high speed, and allows the moisture absorption amount and hydrophilicity to be adjusted.

[0030] <Composition of polymer composition> The composition of the polymer composition of the first embodiment is not particularly limited, but it is preferable to limit the ratio of carboxy groups to inorganic cations in the polymer within a certain range in view of the constraints imposed by the production method in which synthesis is carried out in an aqueous solution and the humidity control function. That is, since the valence of the carboxy group is (-1) and the valence of the inorganic cation is (+x (x = 1, 2, 3, 4)), if the amount of carboxy groups in the polymer composition, n, is [n] mol / g and the amount of inorganic cations, m, is [m] mol / g, then the value will be close to n = m / x. However, because the polymer composition contains monocarboxylic acids and other components, and because the carboxy groups can be in the hydrogen form or in a state where the hydrogen is ionized, the stoichiometric ratio predicted from the charge is not completely limited. In the present invention, the amount of inorganic cations in the polymer composition is preferably 1 to 100 mmol per 1 g of the polymer having a carboxy group, and similarly, the amount of monocarboxylic acid is preferably 1 to 100 mmol per 1 g of the polymer having a carboxy group.

[0031] The total content of the polymer, monocarboxylic acid, and inorganic cation in the polymer composition of the first embodiment is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, particularly preferably 80% by mass or more, and may be 100% by mass, based on the total mass of the polymer composition.

[0032] The polymer composition of the first embodiment can contain other components as long as the effects of the present invention are not impaired. The other components are not particularly limited, but because the polymer composition is a material that is handled under high humidity, antibacterial substances, disinfecting substances, fungicides, components having antifungal properties, and bactericides are preferred. Also, a single material that has multiple effects simultaneously may be used.

[0033] Examples of antibacterial substances include zinc pyrithione, silver ions, and copper ions. Examples of disinfecting substances include various alcohols. Examples of the antifungal agent include azoxystrobin, imazalil, sodium orthophenylphenol, diphenyl, thiabendazole, imazalil, fludioxonil, orthophenylphenol, and pyrimethanil. Examples of disinfectants include chlorous acid and sodium chlorite. These other components may be used alone or in combination of two or more.

[0034] <Organic acid salt> The organic acid salt according to the first embodiment is an organic acid salt comprising the monocarboxylic acid and the inorganic cation. The monocarboxylic acid and the inorganic cation may form an organic acid salt in the polymer composition. Furthermore, when producing the polymer composition, an organic acid salt may be used as the monocarboxylic acid and the inorganic cation. When an organic acid salt is used, the organic acid salt may be dissociated into the monocarboxylic acid and the inorganic cation in the polymer composition.

[0035] The solubility of the organic acid salt in water at 25° C. is preferably 1 to 200 g / 100 mL, more preferably 5 to 100 g / mL, and even more preferably 5 to 75 g / mL. If the solubility is equal to or greater than the lower limit, the water solubility required during synthesis is sufficient, and the reaction rate does not decrease. If the solubility is below this upper limit, the likelihood of unwanted unreacted molecules remaining in the solution or in the resulting resin is reduced.

[0036] The organic acid salt is preferably a combination of the monocarboxylic acid and the inorganic cation such that the solubility is 1 to 200 g / 100 mL, for example, a combination of 3-hydroxy-3-methylbutyric acid and a divalent inorganic cation. Specifically, examples of organic acid salts include divalent organic acid salts such as calcium 3-hydroxy-3-methylbutyrate and magnesium 3-hydroxy-3-methylbutyrate. Divalent organic acid salts can undergo LCST phase separation within the range of 0°C to 80°C, which is close to room temperature. At the same time, monovalent inorganic cations such as Li, Na, K, etc. and organic acid salts thereof may be contained in order to adjust the moisture absorption amount and hydrophilicity. The organic acid salts may be used alone or in combination of two or more.

[0037] <Synthesis of polymer composition> The polymer composition of the first aspect can be obtained by mixing the polymer, the monocarboxylic acid, the inorganic cation, and, if necessary, the other components. The organic acid salt may be formed in advance from the monocarboxylic acid and the inorganic cation, and the organic acid salt, the polymer, and, if necessary, the other components, are mixed to produce the polymer composition. Specifically, the polymer composition can be synthesized by the following method. The polymer is introduced into pure water, and then the organic acid salt consisting of the monocarboxylic acid and the inorganic cation, and optionally the other components, are mixed and stirred at room temperature (e.g., 20°C) and maintained for a predetermined time, whereby the reaction proceeds spontaneously and a solution containing the polymer composition of the present invention is obtained. To accelerate the reaction, it is also effective to apply heat or ultrasonic waves for a certain period of time during the synthesis.

[0038] "Second Aspect" The polymer composition of the second embodiment will be described below.

[0039] <Polymer> The polymer used in the second embodiment is a polymer containing 1.0 to 20.0 mmol / g of carboxy groups, and is a polymer containing 1.0 to 20.0 mmol / g of carboxy groups per dry resin weight. As the polymer, the same polymers as those mentioned in the first embodiment can be used.

[0040] <Polycarboxylic acid> The polycarboxylic acid used in the second embodiment is a polycarboxylic acid having a molecular weight of 100 to 1,000. Polyvalent means that one molecule has a plurality of carboxy groups, and the number of carboxy groups is two or more, preferably two to six from the viewpoint of stability in polymer materials.

[0041] The molecular weight of the polycarboxylic acid is 100 to 1,000. A molecular weight of 100 or more is advantageous in terms of suppressing volatile components, and provides good solubility in water and ion exchange reactivity. In particular, a molecular weight of 120 or more is preferred in terms of suppressing volatile components, more preferably 150 or more, even more preferably 170 or more, and still more preferably 200 or more. If the molecular weight is 1000 or less, the solubility in water and the ion exchange reactivity are good. In particular, if the molecular weight is 800 or less, it is preferable in terms of solubility in water, and if it is 600 or less, it is more preferable.

[0042] As the polycarboxylic acid, a chelating agent having a molecular weight of 100 or more and having a plurality of carboxy groups is suitable. In particular, a chelating agent having an amino group (hereinafter also referred to as an aminocarboxylic acid type chelating agent) is preferred. Specific examples include EDTA (ethylenediaminetetraacetic acid), NTA (nitrilotriacetic acid), DTPA (diethylenetriaminepentaacetic acid), HEDTA (hydroxyethylethylenediaminetriacetic acid), TTHA (triethylenetetraminehexaacetic acid), PDTA (1,3-propanediaminetetraacetic acid), DTPA-OH (1,3-diamino-2-hydroxypropanetetraacetic acid), HIDA (hydroxyethyliminodiacetic acid), and GEDTA (glycol ether diaminetetraacetic acid). Among these, EDTA, NTA, DTPA, and HEDTA are preferred from the viewpoints of solubility in water and stability in polymeric materials. The polycarboxylic acids may be used alone or in combination of two or more.

[0043] In addition to the above-mentioned chelating agents, other polycarboxylic acids such as tartaric acid, tartronic acid, malic acid, citric acid, and isocitric acid may also be used as the polycarboxylic acid.

[0044] <Inorganic cation> As the inorganic cation used in the second embodiment, the same inorganic cations as those mentioned in the first embodiment can be used.

[0045] <Composition of polymer composition> The composition of the polymer composition of the second embodiment is not particularly limited, but it is preferable to limit the ratio of carboxy groups to inorganic cations in the polymer within a certain range in view of the constraints imposed by the production method in which synthesis is carried out in an aqueous solution and the humidity control function. That is, since the valence of the carboxy group is (-1) and the valence of the inorganic cation is (+x (x = 1, 2, 3, 4)), if the amount of carboxy groups in the polymer composition, n, is [n] mol / g and the amount of inorganic cations, m, is [m] mol / g, then the value will be close to n = m / x. However, because the polymer composition contains polycarboxylic acids and other components, polycarboxylic acids can form various bonds with inorganic cations, and carboxy groups can be in the hydrogen form or in a state where the hydrogen is ionized, the stoichiometric ratio predicted from the charge is not completely limited. In the present invention, the amount of inorganic cations in the polymer composition is preferably 1 to 100 mmol per 1 g of the polymer having a carboxy group, and similarly, the amount of polycarboxylic acid is preferably 1 to 100 mmol per 1 g of the polymer having a carboxy group.

[0046] The total content of the polymer, polycarboxylic acid, and inorganic cation in the polymer composition of the second embodiment is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, particularly preferably 80% by mass or more, and may be 100% by mass, based on the total mass of the polymer composition.

[0047] The polymer composition of the second embodiment can contain other components as long as the effects of the present invention are not impaired. The other components are not particularly limited, but because the polymer composition is a material that is handled under high humidity, antibacterial substances, disinfecting substances, fungicides, components having antifungal properties, and bactericides are preferred. Also, a single material that has multiple effects simultaneously may be used.

[0048] Examples of antibacterial substances include zinc pyrithione, silver ions, and copper ions. Examples of disinfecting substances include various alcohols. Examples of antifungal agents include azoxystrobin, imazalil, sodium orthophenylphenol, diphenyl, thiabendazole, imazalil, fludioxonil, orthophenylphenol, and pyrimethanil. Examples of disinfectants include chlorous acid and sodium chlorite. These other components may be used alone or in combination of two or more.

[0049] <Organic acid salt> The organic acid salt according to the second embodiment is an organic acid salt comprising the polycarboxylic acid and the inorganic cation. The polycarboxylic acid and the inorganic cation may form an organic acid salt in the polymer composition. Furthermore, when producing the polymer composition, an organic acid salt may be used as the polycarboxylic acid and the inorganic cation. When an organic acid salt is used, the organic acid salt may be dissociated into the polycarboxylic acid and the inorganic cation in the polymer composition.

[0050] The solubility of the organic acid salt in water at 25° C. is preferably 1 to 200 g / 100 mL, more preferably 5 to 100 g / mL, and even more preferably 5 to 75 g / mL. If the solubility is equal to or greater than the lower limit, the water solubility required during synthesis is sufficient, and the reaction rate does not decrease. If the solubility is below this upper limit, the likelihood of unwanted unreacted molecules remaining in the solution or in the resulting resin is reduced.

[0051] In the organic acid salt, since the carboxylic acid is polyvalent, it is possible to bond a plurality of inorganic cations. The organic acid salt is preferably a combination of the polycarboxylic acid and the inorganic cation such that the solubility is 1 to 200 g / 100 mL. For example, the organic acid salt may be an organic acid salt composed of one polycarboxylic acid, a monovalent inorganic cation such as Li, Na, or K, and a divalent inorganic cation in order to adjust the moisture absorption and hydrophilicity of the material. Alternatively, the organic acid salt may be a mixture of an organic acid salt composed of a polycarboxylic acid and a monovalent inorganic cation, and an organic acid salt composed of a polycarboxylic acid and a divalent inorganic cation. These organic acid salts are all free from odor problems and are therefore highly preferred.

[0052] Examples of organic acid salts include EDTA·Na·Fe, EDTA·2Na·Ca, EDTA·2Na·Mg, EDTA·2Na·Cu, EDTA·2Na·Zn, DTPA·Na·Fe, and inorganic cation-bound malate, citrate, and tartrate. The organic acid salts may be used alone or in combination of two or more.

[0053] <Synthesis of polymer composition> The polymer composition of the second aspect can be obtained by mixing the polymer, the polycarboxylic acid, the inorganic cation, and, if necessary, the other components. The organic acid salt may be formed in advance from the polycarboxylic acid and the inorganic cation, and the organic acid salt, the polymer, and, if necessary, the other components, are mixed to produce the polymer composition. Specifically, the polymer composition can be synthesized by the following method. The polymer is added to pure water, and then the organic acid salt composed of the polycarboxylic acid and the inorganic cation, and optionally the other components, are mixed and stirred at room temperature (e.g., 20°C) and maintained for a predetermined time, whereby the reaction proceeds spontaneously and a solution containing the polymer composition of the present invention is obtained. To accelerate the reaction, it is also effective to apply heat or ultrasound for a certain period of time during the synthesis.

[0054] The following description will be common to the polymer composition of the first embodiment and the polymer composition of the second embodiment.

[0055] The lower critical solution temperature of the polymer composition of the present invention is preferably 0 to 80°C. Here, the lower critical solution temperature will be explained. Among polymers (or polymer compositions), there are known some that are hydrophilic and highly soluble in water at low temperatures, but become hydrophobic and insoluble in water above a certain temperature. Such polymers that change their properties depending on the temperature are called temperature-responsive polymers or temperature-responsive polymer compounds. The temperature at which a substance changes from water-soluble to water-insoluble is called the lower critical solution temperature (LCST).

[0056] The lower critical solution temperature of the polymer composition is more preferably 5 to 70°C, and even more preferably 10 to 50°C, since the hygroscopic change is more likely to occur at a temperature close to room temperature. The lower critical solution temperature can be detected by directly observing the endothermic onset temperature in differential scanning calorimetry (DSC), changes in optical properties (transmittance, reflectance), structural changes, and bond changes.

[0057] [Humidity-regulating materials] The humidity-conditioning material of the present invention contains the polymer composition of the present invention, is in the form of particles, and has a median particle size of 0.01 to 1000 μm. The humidity conditioning material may further include inorganic particles.

[0058] Although the polymer composition of the present invention exhibits its functions even in a bulk form, its performance can be improved by increasing the surface area by thinning or microparticulating the polymer composition. Therefore, microparticulating the polymer composition by various methods leads to an increase in the amount and speed of moisture absorption and desorption. The polymer composition may be made fine by a method in which the particle size is controlled by suspension polymerization or the like during synthesis of the polymer used in the present invention, or by a method in which a mass of the polymer used in the present invention is physically pulverized.

[0059] There are no particular restrictions on the pulverization method or the timing of pulverization in the process, but particle size can be controlled using various types of equipment capable of coarse pulverization, medium pulverization, fine pulverization, and ultrafine pulverization, and there is no problem whether wet pulverization or dry pulverization is used. Specific pulverization methods include medium-sized pulverizers such as a mortar, a roll crusher, and a cutter mill; fine pulverizers such as a roller mill, a jet mill, a hammer mill, a pin mill, a ball mill, and a vibration mill; and fine pulverizers such as an attritor and a bead mill. These methods may be used in succession or in combination. Regarding the timing of the pulverization step, the polymer may be pulverized, or the pulverization may be carried out after the synthesis of the polymer composition of the present invention. When the humidity-conditioning material contains inorganic particles, the finely divided polymer composition and the inorganic particles may be mixed, or the polymer composition and the inorganic particles may be mixed and then pulverized.

[0060] The median particle size of the humidity-conditioning material of the present invention is 0.01 to 1000 μm, preferably 0.01 to 100 μm, and more preferably 0.01 to 50 μm, because it can achieve both excellent moisture absorption amount and moisture absorption speed and can be dispersed or formed into a slurry in an aqueous solution. Here, "median particle size" refers to the diameter (abbreviated as d50) at which the larger and smaller particles are equal in volumetric particle size distribution measured by laser diffraction / scattering, when a powder is divided into two at a certain particle size.

[0061] The content of the polymer composition in the humidity-conditioning material is preferably 20% by mass or more, more preferably 50% by mass or more, based on the total mass of the humidity-conditioning material. The upper limit of the content of the polymer composition is not particularly limited and may be 100% by mass. When the humidity-conditioning material contains components other than the polymer composition, the content of the polymer composition is preferably 99.9% by mass or less, more preferably 99% by mass. In order to ensure sufficient moisture absorption, the content of the polymer composition in the humidity-conditioning material is preferably 20 to 100% by mass, more preferably 20 to 99.9% by mass, even more preferably 20 to 99% by mass, and particularly preferably 50 to 99% by mass, relative to the total mass of the humidity-conditioning material.

[0062] The humidity control material of the present invention can contain inorganic particles and other components from the viewpoints of mechanical properties, dimensional stability, thermal properties such as thermal conductivity, etc., other than the amount of moisture absorption and desorption. Examples of the inorganic particles include known inorganic solids such as silica gel, zeolite, activated carbon, etc.; metal organic frameworks. The other components are not particularly limited, but since the humidity control material is a material handled under high humidity conditions, antibacterial substances, sterilizing substances, fungicides, components having antifungal properties, and bactericides are preferable. The inorganic particles and the other components may each be used alone or in combination of two or more.

[0063] When the humidity control material contains inorganic particles, from the viewpoints of dimensional stability and thermal conductivity control, the content of the inorganic particles is preferably 0.1 to 80% by mass, more preferably 0.1 to 50% by mass, and still more preferably 1 to 50% by mass based on the total mass of the humidity control material.

[0064] The form of the humidity control material is particulate. Here, "particulate" means that the aspect ratio (AR = minimum diameter / maximum diameter) of the material form is within a certain range. The defined range of the aspect ratio is 0 < AR ≤ 1, but the particulate in the present invention is defined as 0.01 < AR ≤ 1.

[0065] <Manufacturing method of the humidity control material> The manufacturing method of the humidity control material of the present invention is not particularly limited as long as the blending ratio of each component is appropriate. For example, the polymer composition, the inorganic particles, and other components as required may be uniformly mixed by a known method such as direct stirring with a stirring blade, or mixing and stirring using dispersion in a solvent.

[0066] [Various functional members] The humidity control material of the present invention is in the form of dehydrated and dried powder, but the form at the time of use is not particularly limited, and it can be used in a suitable form according to various applications. For example, the humidity control material can be an aqueous slurry or an aqueous dispersion containing the humidity control material. Although both slurries and dispersions are forms in which solid particles exist in a liquid, they are generally distinguished by their properties. A "slurry" is a heterogeneous mixture in which relatively large solid particles (usually particles with a particle diameter of 1 μm or more) are suspended in a medium, and the solid particles are strongly affected by gravity and tend to settle. "Dispersion" refers to a wide range of systems, including colloidal dispersions (particle diameters are usually around 1 nm to 1 μm), stabilized in solution by thermal motion and Brownian motion. When the particles are submicron to several microns in size, it may be difficult to clearly distinguish between a slurry and a dispersion. In this invention, however, a "slurry" refers to a state in which particles settle without the application of external forces (except gravity), and a "dispersion" refers to a state in which particles are dispersed in a liquid.

[0067] The aqueous slurry or aqueous dispersion containing the humidity-conditioning material can be prepared by a known method using the humidity-conditioning material and an aqueous medium. The aqueous medium includes water and a mixture of water and an organic solvent, and among these, water is preferred. As the organic solvent, a water-miscible solvent is preferred, and examples thereof include alcohols such as methanol, ethanol, n-propanol, and isopropanol; ketones such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol, and propylene glycol; and alkyl ethers of polyalkylene glycols. The aqueous medium may be used alone or in combination of two or more kinds.

[0068] The content of the humidity-conditioning material in the aqueous slurry is preferably 30 to 80 mass %, more preferably 50 to 80 mass %, based on the total mass of the aqueous slurry. The content of the humidity-conditioning material in the aqueous dispersion is preferably from 0.1 to 50% by mass, more preferably from 0.1 to 30% by mass, based on the total mass of the aqueous dispersion.

[0069] The humidity-conditioning material may be a humidity-conditioning member in which the humidity-conditioning material is bound to a nonwoven fabric directly or via a binder. The humidity-conditioning member in which the humidity-conditioning material is bound to the nonwoven fabric directly or via a binder can be prepared by a known method using a known binder. The binder is not particularly limited, but examples thereof include acrylic resins, vinyl acetate resins, polyvinyl alcohol, and epoxy resins. The binder may be used alone or in combination of two or more kinds.

[0070] The polymer composition of the present invention is not particularly limited in its form when used, and can be used in a suitable form depending on various applications. For example, the polymer composition may be a crosslinkable precursor containing 20% ​​by weight or more of the polymer composition. In the present invention, the "crosslinkable precursor" is a composition containing a material that accelerates a polymerization reaction in the presence of a stimulus such as heat or light, or an acid or alkali. The crosslinkable precursor may consist solely of the polymer composition of the present invention, or may contain, in addition to the polymer composition of the present invention, a composition containing a monomer or oligomer constituting any thermosetting resin other than the polymer composition of the present invention, or a monomer or oligomer constituting a photoreactive resin, as a polymerization component (hereinafter also referred to as "other polymerizable composition"). The crosslinkable precursor also includes a composition having a blending composition such that, when the crosslinkable precursor is crosslinked, the content of the crosslinked product of the polymer composition of the present invention is 20 mass% or more relative to the total mass of the crosslinked product of the crosslinkable precursor. Alternatively, the crosslinkable precursor may be one in which the polymer (crosslinked product) obtained after crosslinking of any crosslinkable precursor contains 20% by mass or more of the polymer composition of the present invention. Here, "any crosslinkable precursor" includes the other polymerizable compositions described above.

[0071] The content of the polymer composition in the crosslinkable precursor is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass or more, and particularly preferably 70% by mass or more, relative to the total mass of the crosslinkable precursor. It may also be 100% by mass, 99% by mass or less, or 90% by mass or less.

[0072] The crosslinkable precursor may further contain, in addition to the polymer composition of the present invention, components other than the polymer composition of the present invention and other polymerizable compositions (other components), as necessary. The other components are not particularly limited, but since the humidity-conditioning material is a material that is handled in high humidity environments, the crosslinkable precursor may contain, for example, an antibacterial substance, a disinfecting substance, an antifungal agent, a component having antifungal properties, or a bactericide.

[0073] The polymer composition may be used as a humidity control member in which the polymer composition is bound to a nonwoven fabric directly or via a binder. Examples of the binder include those exemplified above.

[0074] The crosslinkable precursor may be a crosslinkable precursor solution diluted with a solvent, i.e., the crosslinkable precursor solution contains a crosslinkable precursor and a solvent. Examples of the solvent include the aqueous media exemplified above. The content of the crosslinkable precursor in the crosslinkable precursor solution is preferably 5 to 90 mass %, more preferably 10 to 70 mass %, based on the total mass of the crosslinkable precursor solution.

[0075] The crosslinkable precursor can be crosslinked to form a crosslinked product. The method for crosslinking the crosslinkable precursor is not particularly limited, and may be, for example, photocrosslinking or thermal crosslinking. The shape of the crosslinked product is not particularly limited, but examples thereof include a film and a block. In the present invention, a film-like crosslinked product obtained by crosslinking a crosslinkable precursor is also referred to as a "film-like polymer composition," and a bulk crosslinked product is also referred to as a "bulk polymer composition." The thickness of the film-shaped polymer composition is not particularly limited, but is preferably, for example, 0.1 to 500 μm. The shape of the bulk polymerization composition is not particularly limited as long as it is in the form of a film.

[0076] The crosslinkable precursor may be bound to a nonwoven fabric directly or via a binder to form a humidity control member. Examples of the binder include those exemplified above.

[0077] Furthermore, the polymer composition of the present invention undergoes significant changes in the moisture content of the resin due to changes in temperature and humidity. Furthermore, because changes in moisture content are accompanied by rapid and efficient transfer of water and heat associated with water movement, the polymer composition can be used as a suitable material for heat transport. That is, the polymer composition of the present invention is expected to function as a good heat exchange or heat transport material when it is brought into contact with a part of a heat exchanger, heat transporter, or radiator, directly or via a binder, with a refrigerant containing at least water. Examples include a heat exchange element in which the polymer composition of the present invention and a refrigerant containing at least water contact a part of a heat exchanger, directly or via a binder; a heat transport element in which the polymer composition of the present invention and a refrigerant containing at least water contact a part of a heat transporter, directly or via a binder; and a heat dissipation element in which the polymer composition of the present invention and a refrigerant containing at least water contact a part of a radiator, directly or via a binder. The heat exchangers, heat transporters, and radiators referred to here are devices used to exchange or transfer thermal energy between two objects or locations that possess different amounts of thermal energy. They are generally used to heat or cool objects by efficiently transferring heat from an object with a higher temperature to an object with a lower temperature. Specific examples of heat exchangers, heat transporters, and radiators include shell-and-tube heat exchangers, plate heat exchangers, finned-tube heat exchangers, jacketed heat exchangers, double-pipe heat exchangers, spiral heat exchangers, heat pipes, vapor chambers, heat sinks, etc. These heat exchangers, heat transporters, and radiators are often composed of metal plates, metal tubes, and metal fins made of metals such as copper and aluminum with good thermal conductivity, but any member with good thermal conductivity can be used regardless of the material type.

[0078] [Principle of action] The polymer composition of the present invention is likely to change its hydrophilicity and hydrophobicity at a temperature close to room temperature. Specifically, the lower critical solution temperature for water is likely to be 0 to 80°C. Due to this effect, in response to a small temperature change from room temperature, an internal structure or pores that are reversibly divided into hydrophilic and hydrophobic parts inside the particles are manifested, and it becomes possible to also manifest the volume change associated with this phenomenon. Moreover, due to its sharp temperature responsiveness, both the water vapor adsorption / desorption on the particle surface and the absorption / diffusion / release rate inside the particles are fast, enabling excellent moisture absorption / desorption rate, heat transfer, heat exchange, and heat dissipation. Also, the minute volume change during the hydrophilicity / hydrophobicity change may add a favorable effect on the water vapor adsorption / moisture movement between particles and the mobility of water molecules. Due to these properties, the polymer composition of the present invention can achieve both the moisture absorption / desorption amount and the moisture absorption / desorption rate with a smaller temperature change than before, and can be used as a material for a humidity control material, heat exchanger, heat transporter, and radiator with very high energy efficiency.

Examples

[0079] The present invention will be specifically described by the following examples, but the present invention is not limited to the following examples.

[0080] [Measurement and evaluation] <Confirmation of phase separation at LCST (visual observation, measurement by DSC)> In the case of transparent or translucent bulk or thin film polymer compositions of the present invention, phase separation due to temperature changes occurs when the temperature is increased from a temperature below the LCST. This occurs at temperatures above the phase separation temperature, and the resulting cloudiness is visible and can be confirmed by visual or optical measurements. However, in powder samples, light scattering due to their size and shape persists even below the LCST, making this change difficult to confirm visually or by optical measurements. For this reason, we used the presence or absence of dehydration and endothermic reactions that accompany phase separation as indicators of the presence or absence of phase separation. The presence or absence of endothermic reactions can be measured by placing the resin, which has been sufficiently hydrated in an aqueous solution, in a sealed AlCr pan and then measuring the temperature using a differential scanning calorimeter (DSC).

[0081] <Measurement of saturated water vapor amount (adsorption isotherm measurement)> A graph obtained by measuring the change in pressure and adsorption amount while the measurement material is kept at a constant temperature is called an adsorption isotherm. Generally, the horizontal axis shows the relative pressure (P / PO) obtained by dividing the equilibrium pressure by the saturated vapor pressure, and takes values ​​between 0 and 1. When P / PO≒1, this means that the adsorbed gas condenses within the sample tube. In other words, the adsorption isotherm measures the adsorbate density at a pressure lower than the saturated vapor pressure, where the interaction between the solid and the adsorbed molecules occurs and adsorption and condensation begin, which is higher than the gas phase. In addition, the constant volume method generally expresses the amount of adsorption as V / ml(STP)g -1 This is expressed as the volume of gas at standard conditions (0°C, 1 atm). In this study, this value was converted into the amount of water vapor adsorbed per measured material (g / g) and used as an adsorption index. The water vapor adsorption isotherm was measured using BELSORP-AQUA (MicrotracBEL). To confirm the changes and differences in moisture absorption and desorption amounts when the temperature is changed near the ambient temperature, measurements were performed at two temperatures: 20°C (room temperature) and 50°C (heated). Figure 1 shows an example of a water vapor adsorption isotherm in the present invention. Here, the amount of water vapor adsorption when the relative humidity is R% and the measurement temperature is T°C is defined as W(R [%], T [°C]). Based on Figure 1, we consider the process of adsorbing water vapor at room temperature (20°C) and desorbing it by heating to 50°C. Because it is expected that the phase separation effect will be significant in high humidity regions, we will assume that this material can fully desorb water vapor even at a relative humidity of 60%. When this index is used, the absolute value of W(95,20) - W(60,50) (hereinafter referred to as the "absolute value of difference value (1)") can be used as an index of the change in adsorption amount. The absolute value of difference value (1) represents the amount of change between each state, and the larger the absolute value of difference value (1), the better the temperature responsiveness, moisture absorption / desorption speed, and moisture absorption / desorption amount. Therefore, a large absolute value of difference value (1) indicates that the material is suitable as a humidity-regulating material. Similarly, if the absolute value of W(95,50)-W(60,50) (hereinafter also referred to as "absolute value of difference value (2)") and the absolute value of W(95,50)-W(95,20) (hereinafter also referred to as "absolute value of difference value (3)") are large, it can be said that the amount of adsorption and desorption between each state is large, and therefore the larger the absolute value of difference value (2) and the absolute value of difference value (3), the more suitable the humidity-regulating material can be determined to be. The larger the absolute value of each difference value, the better. Specifically, it is preferably 1.0 or more, and more preferably 2.0 or more. There is no particular upper limit to the absolute value of the difference value, but if it is too large, volume change will occur, which may be disadvantageous in terms of stability. Therefore, the absolute value of the difference value is preferably 10.0 or less, and more preferably 7.0 or less. It is preferable that the absolute values ​​of the difference value (1), the difference value (2), and the difference value (3), which are calculated as indicators of the change in the amount of adsorption, are all large (for example, 1.0 or more), but if one or two of the three are 1.0 or more, it can be determined that the result is sufficiently good.

[0082] <Median particle size measurement> The results were measured using a laser diffraction particle size distribution analyzer MT3300EXII (Microtrac Bell) using water as the dispersion medium, and expressed on a volume basis as the median particle size (d50).

[0083] <Analysis of volatile components (analysis of odor components)> The amount of volatile components of low molecular weight compounds that cause odors was quantified by headspace gas chromatography. The analytical equipment used was an Agilent 7890 / Agilent 5975 GC / MS. Odor assessment was carried out by multiple people at room temperature (20°C) and the following criteria were used. (Judgment criteria) ○: No one can smell it ×: One or more people found the smell unpleasant

[0084] [Example 1] <Synthesis of polymer composition> The polymer composition was synthesized by the following procedure. (1) Commercially available weakly acidic ion exchange resin Relite WK60L (manufactured by Mitsubishi Chemical Corporation) was pulverized for a total of 9 minutes using a small high-speed cutter mill (rotation speed: 30,000 rpm) to obtain a dry powdered pulverized resin. (2) The organic acid salt solution was prepared by dissolving 1000 mM calcium 3-hydroxy-3-methylbutyrate (HMB calcium) (Tokyo Chemical Industry Co., Ltd.) in 5.0 g of pure water. The crushed resin (1) was added to the organic acid salt solution, and the mixture was stirred gently and then allowed to stand at room temperature (20°C) for 72 hours. (3) A magnetic funnel was attached to the suction filter bottle, and quantitative filter paper (No. 5C) was used as the filter material, and the solution from (2) was subjected to suction filtration using a pump. The immersed resin was separated from the solution, and the drained resin was used as the polymer composition for each measurement.

[0085] The weakly acidic ion exchange resin used here, Relite WK60L, is a polymer containing 11.1 mmol / g of carboxyl groups per dry resin weight. 3-Hydroxy-3-methylbutyric acid is a monocarboxylic acid with one hydroxy group and a molecular weight of 118.1. The solubility of calcium 3-hydroxy-3-methylbutyrate in water at 25°C is 25 g / 100 mL.

[0086] <Adsorption isotherm measurement> Adsorption isotherm measurements were carried out using BELSORP-AQUA (manufactured by MicrotracBEL) according to the following procedure. (1) After drying a Pyrex (registered trademark) standard sample tube under reduced pressure for 1 hour, the polymer composition was weighed so that the weight after pretreatment would be 0.05 g and placed in the sample tube. (2) The sample tube from (1) was set in the pretreatment apparatus, and drying under reduced pressure was carried out at 85 °C for 4 hours. (3) Immediately after the pretreatment was completed, it was weighed with an analytical balance to calculate the amount of the polymer composition to be measured. (4) After weighing, the sample tube was set in the measurement section of the BELSORP-AQUA main body, and the measurement conditions and the calculated amount of the polymer composition were input and measured. The measurement conditions are as follows. (Measurement conditions) · Adsorbed substance: H2O · Adsorption temperature: 20 °C and 50 °C · Equilibrium time: 200 seconds

[0087] <DSC measurement> DSC measurement was carried out using DSC7020 (manufactured by Hitachi High-Tech Sciences Corporation). The polymer composition was weighed with an analytical balance at 5 - 10 mg in a simple hermetic container made of AlCr. When there was a lot of moisture remaining on the surface during weighing, after taking the polymer composition with a spatula, the surface moisture was adsorbed with filter paper or the like and then weighed. The simple hermetic container containing the polymer composition, which was caulked with a dedicated caulking machine, was measured as a sample. The measurement conditions are as follows. (Measurement conditions) · Step1: The temperature was decreased from 30 °C to 0.1 °C at 10 °C / min and held at 0.1 °C for 10 minutes. · Step2: After Step1, the temperature was increased from 0.1 °C to 95 °C at 3 °C / min, and the temperature increase data of Step2 was used as the measurement data.

[0088] <Analysis of volatile components (odor analysis)> Analysis of the volatile components of the polymer composition was measured by headspace gas chromatography. In this analysis, 0.5 g of the polymer composition was weighed into a headspace vial (volume 20 mL), and the vial was kept in a heater set at 80° C. for 30 minutes. The amount of gas generated was measured by injecting 1 mL of the gas phase in the vial into a GC. The equipment and measurement conditions used are as follows. The lid of 0.5 g of polymer composition placed in a vial was opened, and the presence of an odor at room temperature was also used as a criterion for judgment. (Equipment used and measurement conditions) GC / MS: Agilent 7890 / Agilent 5975 (Agilent) Column: DB-WAX (inner diameter 250 μm x film thickness 0.25 μm x length 30 m) Heating conditions: After holding at 40°C for 5 minutes, the temperature was raised to 240°C at a rate of 10°C / min and held at the maximum temperature for 20 minutes.

[0089] <Evaluation items> As an evaluation item of the polymer composition, the median particle size (d50) was measured using a laser diffraction particle size distribution analyzer. In addition, the detected low molecular weight (μg / g) was measured by headspace gas chromatography, and odor evaluation (presence or absence of odor by sensory evaluation at room temperature) was also performed. In addition, W(95,20), W(60,50), and W(95,50) were measured in water vapor adsorption isotherms, and the absolute values ​​of W(95,20)-W(60,50), W(95,50)-W(60,50), and W(95,50)-W(95,20) were calculated as indicators of the change in adsorption amount. The phase separation onset temperature T_dem (endothermic onset), which is an endothermic reaction detected by DSC measurement, was defined as the lower critical solution temperature. The results are shown in Table 1. In the table, "ND" means that the result was below the detection limit.

[0090] The headspace chromatography results showed that 6 μg / g of acetic acid and 0.1 μg / g of HMB (3-hydroxy-3-methylbutyric acid) were detected, but the odor of the polymer composition placed in the vial was indistinguishable at room temperature, so no odor problems arose. In addition, W(95,20)-W(60,50) was 1.04, W(95,50)-W(60,50) was 3.01, and W(95,50)-W(95,20) was 1.97, all of which were above 1.0 and showed good results.

[0091] [Example 2] A polymer composition was synthesized and various measurements and evaluations were carried out in the same manner as in Example 1, except that the organic acid salt aqueous solution used was prepared by dissolving 1000 mM ethylenediaminetetraacetic acid disodium magnesium tetrahydrate (EDTA·2Na·Mg tetrahydrate) (manufactured by Dojindo Laboratories) in 5.0 g of pure water. The results are shown in Table 1. The EDTA used here is a polycarboxylic acid with a molecular weight of 292.2. The solubility of EDTA·2Na·Mg in water at 25°C is 55 g / 100 mL.

[0092] The results were good, with no low molecular weight components in the raw materials that could be the source of the odor detected. Although the phase separation onset temperature T_dem could not be clearly detected by DSC measurement, the values ​​were 1.86 for W(95,20)-W(60,50), 3.51 for W(95,50)-W(60,50), and 1.65 for W(95,50)-W(95,20), all of which were above 1.0, indicating favorable results.

[0093] [Example 3] A polymer composition was synthesized in the same manner as in Example 1, except that the organic acid salt aqueous solution was prepared by dissolving 1000 mM dipotassium L-tartrate hemihydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) in 5.0 g of pure water, and various measurements and evaluations were carried out. The results are shown in Table 1. The L-tartaric acid used here is a polycarboxylic acid with a molecular weight of 150.1.

[0094] Odor evaluation by multiple people (sensory evaluation of odor presence or absence at room temperature) yielded favorable results. Although the phase separation onset temperature T_dem could not be clearly detected by DSC measurement, the values ​​were 0.29 for W(95,20)-W(60,50), 3.19 for W(95,50)-W(60,50), and 2.90 for W(95,50)-W(95,20), with two of the three values ​​being above 1.0, which was a good result.

[0095] [Example 4] A polymer composition was synthesized in the same manner as in Example 1, except that the organic acid salt aqueous solution was prepared by dissolving 1000 mM trisodium citrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) in 5.0 g of pure water, and various measurements and evaluations were carried out. The results are shown in Table 1. The citric acid used here is a polycarboxylic acid with a molecular weight of 192.1. The solubility of trisodium citrate in water at 25°C is 72 g / 100 mL.

[0096] Odor evaluation by multiple people (sensory evaluation of odor presence or absence at room temperature) yielded favorable results. Although the phase separation onset temperature T_dem could not be clearly detected by DSC measurement, it was 0.40 for W(95,20)-W(60,50), 2.08 for W(95,50)-W(60,50), and 1.68 for W(95,50)-W(95,20), and two of the three values ​​were above 1.0, which was a good result.

[0097] [Comparative Example 1] A polymer composition was synthesized in the same manner as in Example 1, except that a weakly acidic ion exchange resin, Relite WK60L (manufactured by Mitsubishi Chemical Corporation), was added to 5.0 g of pure water and no organic acid salt was added, and various measurements and evaluations were carried out. The results are shown in Table 2. The results were good, with no low molecular weight components in the raw materials that could be the source of the odor detected. However, W(95,20)-W(60,50) was 0.44, W(95,50)-W(60,50) was 0.49, and W(95,50)-W(95,20) was 0.05, showing a certain degree of moisture absorption and desorption, but not a significant effect compared to conventional materials.

[0098] Comparative Example 2 A polymer composition was synthesized in the same manner as in Example 1, except that a solution of 1000 mM calcium acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) dissolved in 5.0 g of pure water was used as the organic acid salt aqueous solution, and various measurements and evaluations were carried out. The results are shown in Table 2. The acetic acid used here is a monocarboxylic acid having no hydroxy group and a molecular weight of 60.1.

[0099] The W(95,20)-W(60,50) was 1.47, the W(95,50)-W(60,50) was 4.76, and the W(95,50)-W(95,20) was 3.29, indicating excellent moisture absorption and desorption properties. However, headspace chromatography measurement detected 110 μg / g of acetic acid, and the polymer composition placed in the vial gave off an irritating odor at room temperature, resulting in odor problems.

[0100] Comparative Example 3 A polymer composition was synthesized in the same manner as in Example 1, except that a solution of 0.1 mol / L sodium hydroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) dissolved in 5.0 g of pure water was used instead of the aqueous solution of organic acid salt, and various measurements and evaluations were carried out. The results are shown in Table 2. Odor evaluation by multiple people (sensory evaluation of odor presence or absence at room temperature) yielded favorable results. However, W(95,20)-W(60,50) was 0.36, W(95,50)-W(60,50) was 0.60, and W(95,50)-W(95,20) was 0.24, showing a certain degree of moisture absorption and desorption, but not a significant effect compared to conventional materials.

[0101] Comparative Example 4 A polymer composition was synthesized in the same manner as in Example 1, except that a solution of 0.1 mol / L potassium hydroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) dissolved in 5.0 g of pure water was used instead of the aqueous solution of organic acid salt, and various measurements and evaluations were carried out. The results are shown in Table 2. Odor evaluation by multiple people (sensory evaluation of odor presence or absence at room temperature) yielded favorable results. However, W(95,20)-W(60,50) was 0.30, W(95,50)-W(60,50) was 0.63, and W(95,50)-W(95,20) was 0.33, showing a certain degree of moisture absorption and desorption, but not a significant effect compared to conventional materials.

[0102] Comparative Example 5 A polymer composition was synthesized in the same manner as in Example 1, except that the organic acid salt aqueous solution was prepared by dissolving 1000 mM magnesium acetate tetrahydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) in 5.0 g of pure water, and various measurements and evaluations were carried out. The results are shown in Table 2. The acetic acid used here is a monocarboxylic acid having no hydroxy group and a molecular weight of 60.1.

[0103] W(95,20)-W(60,50) was 0.65, W(95,50)-W(60,50) was 1.95, and W(95,50)-W(95,20) was 1.30, showing excellent moisture absorption and desorption properties. However, odor judgments by multiple people (sensory evaluation at room temperature) revealed an irritating odor, and favorable results were not obtained.

[0104] [Table 1]

[0105] [Table 2]

[0106] As shown in Tables 1 and 2, the material containing neither a carboxylic acid having a predetermined molecular weight nor an inorganic cation (Comparative Example 1) did not exhibit a significant effect in terms of moisture absorption and desorption compared to conventional materials. Similarly, when no carboxylic acid having a predetermined molecular weight was contained (Comparative Examples 3 and 4), the material did not exhibit good properties as a humidity-conditioning material. Furthermore, when the molecular weight of the monocarboxylic acid is less than 80 and the monocarboxylic acid does not have a hydroxy group (Comparative Examples 2 and 5), odor problems occur, making it unsuitable as a material for adjusting environmental humidity. In contrast, materials (Examples 1 to 4) containing a monocarboxylic acid having one or more hydroxy groups and a molecular weight of 80 or more, or a polycarboxylic acid having a molecular weight of 100 or more, and an organic acid salt formed from an inorganic cation, showed good moisture absorption and desorption performance (large moisture absorption amount and large change amount).

Claims

1. a polymer containing 1.0 to 20.0 mmol / g of a carboxy group; a monocarboxylic acid having at least one hydroxy group and a molecular weight of 80 to 1000; an inorganic cation; A polymeric composition comprising:

2. 2. The polymer composition according to claim 1, wherein the organic acid salt formed from the monocarboxylic acid and the inorganic cation has a solubility in water at 25° C. of 1 to 200 g / 100 mL.

3. a polymer containing 1.0 to 20.0 mmol / g of a carboxy group; a polycarboxylic acid having a molecular weight of 100 to 1000; an inorganic cation; A polymeric composition comprising:

4. 4. The polymer composition according to claim 3, wherein the organic acid salt formed from the polycarboxylic acid and the inorganic cation has a solubility in water at 25° C. of 1 to 200 g / 100 mL.

5. 4. The polymer composition according to claim 3, wherein the polycarboxylic acid has a molecular weight of 200 to 1,000.

6. The polymer composition according to any one of claims 1 to 5, wherein the inorganic cation comprises at least one selected from the group consisting of Mg, Ca, Cu, and Zn.

7. 6. The polymer composition according to claim 1, wherein the lower critical solution temperature for water is 0 to 80°C.

8. A humidity-conditioning material comprising the polymer composition according to any one of claims 1 to 5, in the form of particles, and having a median particle size of 0.01 to 1000 µm.

9. The humidity-conditioning material according to claim 8 , further comprising inorganic particles.

10. The humidity-conditioning material according to claim 8 , wherein the content of the polymer composition is 20% by mass or more.

11. An aqueous slurry or aqueous dispersion containing the humidity-conditioning material according to claim 8.

12. A crosslinkable precursor, wherein a polymer obtained by crosslinking any crosslinkable precursor contains 20% by mass or more of the polymer composition according to any one of claims 1 to 5.

13. A crosslinkable precursor solution, in which the crosslinkable precursor according to claim 12 is diluted with a solvent.

14. A film-like polymerizable composition or bulk polymerizable composition obtained by photocrosslinking or thermally crosslinking the crosslinkable precursor according to claim 12.

15. A humidity control member comprising the polymer composition according to any one of claims 1 to 5 bound to a nonwoven fabric directly or via a binder.

16. A humidity control member, comprising the humidity control material according to claim 8 bound to a nonwoven fabric directly or via a binder.

17. A humidity control member comprising the crosslinkable precursor according to claim 12 bound to a nonwoven fabric directly or via a binder.

18. A heat exchange element, in which the polymer composition according to any one of claims 1 to 5 and a refrigerant containing at least water are in contact with a part of a heat exchanger directly or via a binder.

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