JP7344474B2 - High-speed moisture absorption and desorption polymers, fiber structures containing the polymers, resin moldings, air conditioning elements, sorption heat exchange modules, and adsorption heat cycles - Google Patents

Description

The present invention relates to a high-speed moisture absorption and desorption polymer that can exhibit excellent moisture absorption and desorption performance in a short period of time, as well as fiber structures, resin molded products, air conditioning elements, and sorption type heat exchangers containing the polymer. Regarding modules and adsorption heat cycles.

Conventional moisture absorbing elements and adsorption heat cycles used to dehumidify air containing water vapor have used inorganic moisture absorbing materials such as silica gel, zeolite, and activated carbon. It had the disadvantage of poor durability against repeated moisture absorption and release.

In response to this, a moisture-absorbing and desorbing polymer containing a salt-type carboxyl group has been proposed. The moisture-absorbing and desorbing polymer has a high moisture absorption capacity, can be regenerated at low temperatures, and has excellent durability against repeated moisture absorption and desorption (see Non-Patent Document 1). However, there was a problem in that it lacked superiority in moisture absorption rate compared to inorganic moisture absorbing materials. This type of moisture absorbing and releasing polymer is disclosed in Patent Document 1, for example.

Regarding this moisture absorption rate, for example, Patent Document 2 proposes a method of making a moisture absorbing material with an excellent moisture absorption rate by making a moisture absorbing and desorbing polymer into a porous body having pores of a specific size. There is. Patent Document 3 proposes a method in which the carboxyl group contained in a moisture-absorbing and desorbing polymer is made into a potassium salt type to exhibit an excellent moisture absorption rate. However, there is still a problem in that it has not been able to exhibit a moisture absorption rate superior to that of inorganic moisture absorption materials.

Due to these problems, there is currently no moisture absorbent material that can exhibit both excellent moisture absorption amount and moisture absorption rate. On the other hand, the performance of the adsorption type heat cycle is determined by how quickly a large amount of moisture can be absorbed, that is, the amount of moisture absorbed and the rate of moisture absorption, so there is a limit to the performance of the adsorption type heat cycle. With the current performance of adsorption heat cycles, it is difficult to miniaturize the equipment, and its widespread use has been delayed.The problem of insufficient performance of the adsorbent is particularly noticeable in on-vehicle adsorption refrigeration cycles, which have limited installation space. , which is an impediment to practical application.

Japanese Patent Application Publication No. 8-225610 Japanese Patent Application Publication No. 2000-017101 Japanese Patent Application Publication No. 2001-011320

Kiyoshi Saito, 22 others, “Basic theory and latest technology of desiccant air conditioning systems”, 1st edition, S&T Publishing, September 2015, p. 75-83.

The object of the present invention is to provide a polymer that has high moisture absorption and desorption properties and can express the moisture absorption and desorption properties in a short time, that is, has an excellent moisture absorption and release rate, and a fibrous structure containing the polymer. The present invention provides resin molded products, air conditioning elements, sorption heat exchange modules, and adsorption heat cycles.

The inventors of the present invention have conducted intensive studies focusing on the moisture absorption/desorption performance of moisture absorption/desorption materials, particularly the moisture absorption/desorption rate. As a result, they discovered that by using a bulky, low-charge density, low-coordination organic onium ion as the counter cation of the carboxyl group, the moisture absorption rate of the polymer could be greatly improved, leading to the completion of the present invention. Ta.

That is, the present invention is achieved by the following means.
(1) An organic polymer containing 2.0 to 8.0 mmol/g of carboxyl groups whose countercation is an organic onium ion and having a crosslinked structure, wherein the organic onium ion is an aliphatic ammonium ion, a pyridinium ion, etc. at least one type selected from the group consisting of ion and imidazolium ion, all the alkyl groups contained in the organic onium ion have 1 to 4 carbon atoms, and the organic onium ion has 1 to 4 carbon atoms. A high-speed moisture absorbing and releasing polymer characterized by a molecular weight of 1 to 20 .

( 2 ) The high-speed moisture absorption and desorption polymer according to (1), characterized in that the polymer has a fibrous, particulate, or film-like shape.

( 3 ) A fibrous structure containing the high-speed moisture absorbing and releasing polymer according to (1) or ( 2 ).
( 4 ) A resin molded product containing the high-speed moisture absorbing and desorbing polymer according to (1) or ( 2 ).

( 5 ) An air conditioning element containing the high-speed moisture absorbing and desorbing polymer according to (1) or ( 2 ) and having a plurality of gas passages.
( 6 ) A sorption type heat exchange module, characterized in that the high-speed moisture absorbing and desorbing polymer according to (1) or ( 2 ) is attached to at least a portion of the surface of the heat exchange module.
( 7 ) An adsorption heat cycle characterized by containing the high-speed moisture absorbing and desorbing polymer according to (1) or ( 2 ) as an adsorption core.

The fast moisture absorbing and desorbing polymer of the present invention uses a bulky, low-coordination organic onium ion with low electron density as the counter cation of the carboxyl group, which is the hydrophilic part, so that the ion dissociates quickly during water vapor sorption. , can exhibit excellent moisture absorption rate. In addition, when the high-speed moisture absorption and desorption polymer is used as a sorption core, it is possible to provide a highly efficient and energy-saving sorption heat cycle.

FIG. 2 is a diagram showing an example of a single-tiered sheet obtained by processing a moisture absorbing and releasing sheet into a corrugated shape. It is a figure which shows an example of the sorption element which processed the moisture absorption/release sheet into a honeycomb shape. It is a figure which shows an example of the moisture absorption and release element which processed the moisture absorption and desorption sheet|seat and made it into the shape of a rotor. 4 is a diagram showing an example of a desiccant air conditioning system using the rotor element shown in FIG. 3. FIG. FIG. 2 is a diagram showing an example of a moisture absorbing and desorbing block element in which the single-tiered sheets shown in FIG. 1 are stacked so that the ventilation directions are in the same direction. FIG. 2 is a diagram showing an example of a moisture absorbing and desorbing block element in which the single-tiered sheets shown in FIG. 1 are alternately laminated so that the ventilation directions are in different directions. FIG. 6 is a diagram showing an example of a batch switching type humidity control system using the block elements shown in FIG. 5. FIG. FIG. 2 is a diagram showing an example of a sorption heat exchange module using a high-speed moisture absorption and desorption polymer. 9 is a diagram showing an example of an adsorption heat pump system using the adsorption heat exchange module shown in FIG. 8. FIG.

The present invention will be explained in detail below. First, the fast moisture absorbing and desorbing polymer of the present invention has a crosslinked structure and has a carboxyl group (hereinafter referred to as organic onium salt It is necessary that the polymer contains 2.0 to 8.0 mmol/g of 2.0 to 8.0 mmol/g of carboxyl groups. In the present invention, by using an organic onium salt type carboxyl group, the dissociation rate of ion pairs and the flexibility of the polymer chain are increased, and the moisture absorption rate is dramatically improved compared to conventional highly moisture absorbing and desorbing polymers. It is characterized by

The amount of organic onium salt type carboxyl group in the fast moisture absorbing and releasing polymer according to the present invention is 2.0 to 8.0 mmol/g, preferably 3.0 to 8.0 mmol/g, more preferably 3.0 mmol/g. ~6.0 mmol/g. If the amount of organic onium salt type carboxyl group is less than 2.0 mmol/g, sufficient moisture absorption and desorption performance may not be obtained, and if it exceeds 8.0 mmol/g, the This may cause problems such as severe swelling and insufficient dimensional stability of the high-speed moisture absorption/desorption polymer, or moisture absorption/desorption performance reaching a plateau while the reaction time for hydrolysis during production becomes longer. be.

Further, all the alkyl groups contained in the organic onium ion have 1 to 4 carbon atoms. If the onium ion does not contain carbon, there is a problem that the coordinating property becomes high and a sufficient moisture absorption rate cannot be obtained, or the stability of the counter cation is poor and it easily evaporates and transpires. Furthermore, if the number of carbon atoms in the alkyl group contained in the onium ion exceeds 4, the hydrophobicity may become high and a problem may arise in that sufficient moisture absorption performance cannot be obtained.

Further, the number of carbon atoms contained in the organic onium ion is preferably 1 to 20, more preferably 2 to 10, and even more preferably 4 to 8. If the onium ion does not contain carbon, there is a problem that the coordinating property becomes high and a sufficient moisture absorption rate cannot be obtained, or the stability of the counter cation is poor and it easily evaporates and transpires. Furthermore, if the number of carbon atoms contained in the organic onium ion exceeds 20, the hydrophobicity may become high and a problem may arise in that sufficient moisture absorption performance cannot be obtained.

It is desirable that the total amount of organic onium ions bound is 2 mmol/g or more in order to obtain sufficient moisture absorption performance. That is, if two types of organic onium ions, dimethylimidazolium ion and tetrabutylammonium ion, are combined, it is desirable that the total amount of dimethylimidazolium ion and tetrabutylammonium ion is 2 mmol/g or more. . Note that the upper limit of the amount of bonding is the maximum amount that can be bonded to the carboxyl group in the high-speed moisture absorbing and desorbing polymer.

Note that even if the amount of carboxyl groups in the fast moisture absorption/desorption polymer of the present invention is more than 2 mmol/g, moisture absorption/desorption performance can be obtained as long as 2 mmol/g of organic onium ions are bonded as described above. . However, carboxyl groups to which organic onium ions are not bonded simply exist without being able to effectively utilize their potential moisture absorption and desorption properties, and the advantages of having a large amount of carboxyl groups in terms of moisture absorption and desorption do not appear. In order to realize this advantage, it is desirable that organic onium ions are bonded to at least 50 mol% or more, preferably 70 mol% or more of the entire carboxyl group.

In addition, cations other than the above-mentioned organic onium ions can also be contained as salts of carboxyl groups in the high-speed moisture absorbing and desorbing polymer of the present invention. Examples include cations of alkali metals such as Li, Na, K, Rb, and Cs, cations of alkaline earth metals such as Be, Mg, Ca, Sr, and Ba, and inorganic onium ions such as NH ₄ ⁺ and PH ₄ ⁺ . be able to.

Examples of the organic onium ions employed in the present invention include primary to quaternary ammonium ions, primary to quaternary phosphonium ions, primary to tertiary oxonium ions, primary to tertiary sulfonium ions, and the like. Among these, primary to quaternary ammonium ions are preferred, and quaternary ammonium ions are more preferred.

Examples of the quaternary ammonium ion include aliphatic ammonium ion, pyrrolidium ion, piperidinium ion, morpholinium ion, pyrolium ion, oxazolium ion, thiazolium ion, imidazolium ion, pyrazolium ion, 1,2 , 3-triazolium ion, 1,2,4-triazolium ion, pyridinium ion, quinolinium ion, carbazolium ion and the like. Specifically, tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, benzyltrimethylammonium, 1,3-dimethylimidazolium, 1-ethyl-3-methylimidazolium, 1-methyl-3-propylimidazo 1-butyl-3-methylimidazolium, 1-benzyl-3-methylimidazolium, 1-methylpyridinium, 1-ethylpyridinium, 1-propylpyridinium, 1-butylpyridinium, and the like.

Particularly preferred organic onium ions for the present invention include, for example, tetramethylammonium, ethyltrimethylammonium, diethyldimethylammonium, propyltrimethylammonium, 1,3-dimethylimidazolium, 1-ethyl-3-methylimidazolium, 1-methyl Examples include pyridinium and 1-ethylpyridinium.

Further, the high-speed moisture absorption/desorption polymer of the present invention must have a crosslinked structure in order to exhibit high moisture absorption/desorption performance and maintain shape stability during moisture absorption. This crosslinked structure is not particularly limited as long as it does not affect the moisture absorption and desorption performance that is the objective of the present invention and the performance of products that take advantage of this performance. Alternatively, it may have any structure such as a crosslinked crystal structure.

Further, the form of the high-speed moisture absorbing and desorbing polymer in the present invention is not particularly limited, and may be appropriately selected from particulate, fibrous, film, and the like. In the case of particles, they may not only be in the form of dehydrated and dried powders, but also in the form of emulsions dispersed in water, and the form can be selected according to various uses, and they can be used as additives in various molded bodies. Therefore, it has a wide range of applications and is useful. In addition, the size of these particles can be appropriately selected depending on the application and is not particularly limited, but if the average particle size is 1000 μm or less, preferably 100 μm or less, the range of application as various additives will expand. Therefore, it has great practical value.

When the high-speed moisture absorbing and desorbing polymer has a fibrous form, it can be easily processed into paper, nonwoven fabrics, woven fabrics, knitted fabrics, fiber molded articles, etc., and is useful because it can be used for a wide variety of applications. Furthermore, in the case of a film, it can be directly subjected to processing such as corrugation, and is useful for applications such as filters.

The high-speed moisture absorption/desorption polymer according to the present invention described above has a high moisture absorption/desorption rate and a saturated moisture absorption rate. Although a perfectly directly proportional relationship does not hold between the moisture absorption and desorption rate and the saturated moisture absorption rate, in order to achieve the excellent moisture absorption and desorption rate and moisture absorption and desorption performance that are the objectives of the high-speed moisture absorption and desorption polymer of the present invention. It is desirable that the saturated moisture absorption rate be at least 20% by weight or more and 40% by weight or more at 20° C., 65% RH (relative humidity) and 20° C., 90% RH, respectively. If the value of this saturated moisture absorption rate is less than 20% by weight or 40% by weight at each relative humidity, the basic moisture absorption performance will be low, and as a result, the moisture release performance will also be poor, and this purpose will not be met. It may not be possible to achieve this.

Next, a method for producing the high-speed moisture absorbing and releasing polymer of the present invention will be described. The fast moisture absorbing and desorbing polymer of the present invention can be produced mainly through the following steps: monomer polymerization step, crosslinked structure introduction step, carboxyl group introduction step, and organic onium ion introduction step. can. Here, the order of each step may be set based on the characteristics of the method employed in each step, and a plurality of steps may be performed simultaneously. Each step will be explained in detail below.

First, there is no particular limitation on the method of introducing a carboxyl group. For example, a method of obtaining a polymer by homopolymerizing or copolymerizing a monomer having a carboxyl group with another monomer that can be copolymerized ( Method 1), a method of polymerizing a monomer having a functional group that can be induced into a carboxyl group, and converting the functional group of the obtained polymer into a carboxyl group by chemical modification (method 2) Alternatively, the above two methods may be carried out by graft polymerization.

As a method of polymerizing a monomer having a carboxyl group in the above first method, for example, a monomer having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, vinylpropionic acid, etc., alone, Alternatively, a method may be mentioned in which two or more of these monomers are copolymerized, or the monomer is copolymerized with another copolymerizable monomer.

The second method for introducing carboxyl groups by the chemical modification method includes, for example, a homopolymer of monomers having a functional group that can be modified into a carboxyl group by chemical modification treatment, or a copolymer of two or more monomers, Or, when a copolymer with other copolymerizable monomers is polymerized and the resulting polymer is modified into carboxyl groups by hydrolysis, and the carboxyl groups obtained by modification are not in the expected salt form. Furthermore, the above method for converting into the salt form is applied.

Monomers that can be used in this way include monomers with nitrile groups such as acrylonitrile and methacrylonitrile, and monomers with carboxylic acid groups such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, and vinylpropionic acid. Examples include anhydrides, ester derivatives, amide derivatives, and ester derivatives having crosslinking properties.

Examples of the above-mentioned anhydrides include maleic anhydride, phthalic anhydride, acrylic anhydride, methacrylic anhydride, and the like. Examples of ester derivatives include alkyl ester derivatives such as methyl, ethyl, and propyl; alkyl ether ester derivatives such as methoxyethylene glycol; cyclic compound ester derivatives such as cyclohexyl and benzyl; hydroxyalkyl ester derivatives such as hydroxyethyl and hydroxypropyl; ) Carboxylic acid alkyl ester derivatives such as acryloyloxyethylsuccinic acid; crosslinkable alkyl esters such as ethylene glycol (meth)acrylate. Examples of the amide derivative include amide compounds such as (meth)acrylamide and dimethyl (meth)acrylamide.

Other methods for introducing carboxyl groups through chemical modification include oxidation of alkenes, halogenated alkyls, alcohols, aldehydes, and the like.

There is no particular limitation on the method of introducing carboxyl groups by the hydrolysis reaction of the polymer in the second method, and known hydrolysis conditions can be used. For example, a carboxyl group is introduced into a crosslinked polymer obtained by polymerizing the above monomers using a basic aqueous solution of an alkali metal hydroxide, such as sodium hydroxide, lithium hydroxide, potassium hydroxide, ammonia, or ammonium hydroxide. or a method of reacting with a strong acid such as nitric acid, sulfuric acid, or hydrochloric acid, or an organic acid such as formic acid or acetic acid to introduce a carboxyl group. The conditions under which the carboxyl group is 2.0 to 8.0 mmol/g can be determined by experimentally clarifying the relationship between reaction factors such as reaction temperature, concentration, and time and the amount of carboxyl group introduced. can be determined.

If the counter cation of the carboxyl group in the polymer into which a carboxyl group has been introduced as described above is not the desired organic onium ion, the polymer is then treated with a solution of an organic onium ion hydroxide, halide, etc. By mixing, at least a portion of the countercation is converted into the desired organic onium ion by ion exchange.

The treatment conditions include immersing the polymer in a solution containing 1 to 5 equivalents, preferably 1.5 to 3 equivalents, of organic onium ions based on the amount of carboxyl groups in the polymer, and heating at 20 to 80°C for 30 to 30 minutes. An example may be processing for 240 minutes.

Furthermore, there are no particular limitations on the method of introducing crosslinks, such as a method of introducing crosslinks by copolymerizing a crosslinkable monomer in the monomer polymerization step of the above-mentioned method for introducing a carboxyl group, or a method of introducing crosslinks by copolymerizing a crosslinkable monomer, or Examples include a post-crosslinking method in which a crosslinking structure is first polymerized and then a crosslinked structure is introduced by a chemical reaction or by physical energy. In particular, it is possible to introduce strong crosslinking through covalent bonds by using a crosslinking monomer in the monomer polymerization step or by chemical post-crosslinking after obtaining the polymer. It is preferable in that it is less susceptible to physical and chemical deterioration due to moisture absorption and release.

In the method of using a crosslinkable monomer in the monomer polymerization step, a crosslinkable vinyl compound is used and copolymerized with a monomer that has a carboxyl group or can be modified into a carboxyl group to create a crosslinked structure based on covalent bonds. It is possible to obtain a crosslinked polymer having the following. However, in this case, crosslinking that is not or is not susceptible to the acidic conditions exhibited by monomers such as acrylic acid, or chemical influences (such as hydrolysis) when modifying carboxyl groups in polymers. It must be a sexual monomer.

Examples of crosslinkable monomers that can be used in the method using a crosslinkable monomer in the monomer polymerization step include glycidyl methacrylate, N-methylolacrylamide, triallyl isocyanurate, triallyl cyanurate, divinylbenzene, and hydroxyethyl methacrylate. , diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, methylenebisacrylamide, etc. Among them, triallyl isocyanurate, triallyl A crosslinked structure using lucyanurate, divinylbenzene, or methylenebisacrylamide is desirable because it is chemically stable even during hydrolysis to introduce a carboxyl group to a crosslinked polymer containing them.

There is also no particular limitation on the method of post-crosslinking; for example, a nitrile group contained in a nitrile polymer containing 50% by weight or more of a vinyl monomer having a nitrile group is reacted with a hydrazine compound or formaldehyde. A post-crosslinking method can be mentioned. Among these, the method using hydrazine compounds is stable against acids and alkalis, and the crosslinked structure itself that is formed is hydrophilic, so it can contribute to improving hygroscopicity. It is extremely superior in that it can introduce strong crosslinks that can maintain the shape of the material. Although the details of the crosslinked structure obtained by this reaction have not been identified, it is presumed to be based on a triazole ring or tetrazole ring structure.

The vinyl monomer having a nitrile group is not particularly limited as long as it has a nitrile group, and specifically, acrylonitrile, methacrylonitrile, ethacrylonitrile, α-chloroacrylonitrile, α-fluoroacrylonitrile, cyanogen Examples include vinylidene chloride. Among these, acrylonitrile is most preferred because it is cost-effective and has a large amount of nitrile groups per unit weight.

There are no particular restrictions on the method of introducing crosslinks by reaction with a hydrazine compound, as long as the desired crosslinked structure can be obtained, and the method includes the concentration of the acrylonitrile polymer and hydrazine compound during the reaction, the solvent used, and the reaction. The time, reaction temperature, etc. can be appropriately selected as necessary. Regarding the reaction temperature, if it is too low, the reaction rate will be slow and the reaction time will be too long, and if it is too high, the raw material acrylonitrile polymer will plasticize and the shape of the polymer will change. The problem of destruction may occur. Therefore, the preferred reaction temperature is 50 to 150°C, more preferably 80 to 120°C. Furthermore, there is no particular limitation on the part of the acrylonitrile polymer to be reacted with the hydrazine compound, and it can be appropriately selected depending on the intended use and the form of the polymer. Specifically, it can be selected as appropriate, such as reacting only on the surface of the polymer, reacting the entire polymer up to its core, or reacting in a limited manner. The hydrazine compounds used here include hydrazine salts such as hydrazine hydrate, hydrazine sulfate, hydrazine hydrochloride, hydrazine nitrate, hydrazine bromate, and hydrazine carbonate, as well as ethylenediamine, guanidine sulfate, guanidine hydrochloride, guanidine nitrate, and phosphorus. Hydrazine derivatives such as acid guanidine and melamine.

The above-described high-speed moisture absorption and desorption polymer of the present invention can be used in a wider range of applications by forming molded articles such as fiber structures and resin molded articles containing the polymer. In particular, when used in molded products such as paper, nonwoven fabrics, woven fabrics, knitted fabrics, sheets, coatings, and foams, the contact area with gas is large and the shape retention property is excellent, resulting in excellent moisture absorption and desorption properties. Useful as a material. The method of constructing these is not particularly limited as long as the fast moisture absorbing and desorbing polymer of the present invention is used. Any method such as one in which a polymer is supported may be used. However, since it is easy to process and inexpensive, better results can be obtained if it is supported by particulate high-speed moisture absorption and desorption polymers.

There are no particular limitations on the method for supporting the high-speed moisture absorbing and desorbing polymer of the present invention, and various methods may be employed, such as mixing or impregnating it into the matrix that constitutes the material, or coating or incorporating it using a binder. I can do it. Further, the high-speed moisture absorbing and desorbing polymer of the present invention may be present inside the matrix or on the surface of the matrix. For example, methods include mixing the polymer in the manufacturing process of paper, nonwoven fabric, woven fabric, knitted fabric, sheet, foam, etc., impregnating these with a slurry of the polymer, or coating them using a binder. Can be adopted.

Particularly preferred methods of using the high-speed moisture absorbing and desorbing polymer of the present invention include using it as a moisture absorbing and desorbing sheet fixed on a suitable base material such as paper, film, or sheet, and using it as a moisture absorbing and desorbing sheet fixed on a suitable base material such as paper, film, or sheet. Examples include a method of fixing it on a base material and using it as a sorption type heat exchange module. In moisture absorbing and desorbing sheets and sorption type heat exchange modules, the surface area of the molded body for moisture absorption and desorption can be increased, which is effective in further increasing the rate of moisture absorption and desorption.

"Fixing" here refers to the state in which the high-speed moisture absorbing and desorbing polymer is fixed on the base material, and there are no particular limitations on the strength or method of fixing. It may be in a fixed state, or it may be in a state where it is immobilized by chemical bonding. In particular, when the fast moisture absorbing and desorbing polymer of the present invention is chemically bonded to the substrate directly or through some compound such as a binder, it is excellent in terms of durability and gives favorable results. .

Further, there is no particular restriction on the amount of the high-speed moisture absorbing/releasing polymer to be fixed on the substrate, and the amount can be appropriately selected and fixed depending on the intended use. However, if the amount of fixing is too large for the amount of base material, the base material such as paper may not be able to withstand the strength, or the moisture absorbing layer becomes thick, and the fast moisture absorbing and desorbing polymer deep in the moisture absorbing layer may not be used effectively and efficiency may drop. Also. If the amount of fixation is too small, the intended moisture absorption and release performance may not be obtained sufficiently. From this point of view, the preferred fixing amount is 5 to 300 g/m ² .

Further, there is no particular limitation on the ratio of the high-speed moisture absorbing and desorbing polymer to materials other than the base material in the fixing part, but from the viewpoint of increasing the moisture absorbing and desorbing performance as much as possible, it is preferable to make the ratio as high as possible. However, since the fast moisture absorbing and desorbing polymer of the present invention has high hydrophilicity, when the fast moisture absorbing and releasing polymer is solely fixed to a substrate, water resistance may be insufficient depending on the application. Therefore, it is possible to fix the adhesive more firmly by using the method described below as necessary. Even in such a case, from the viewpoint of fully expressing the function of the high-speed moisture absorbing and desorbing polymer of the present invention, the proportion of the fixing portion should preferably exceed 50% by weight, and more preferably exceed 70% by weight. This is desirable.

Furthermore, the base material for the moisture absorbing and releasing sheet is not particularly limited, and can be appropriately selected and used depending on the intended use. Examples include paper, nonwoven fabrics, woven fabrics, knitted fabrics, fiber molded bodies, resin molded bodies, films, sheets, metal plates, etc. Materials constituting these base materials include organic and inorganic substances. Or metal, etc., but there is no particular limitation. Among these, forms such as paper, non-woven fabric, or porous sheets have appropriate voids and uneven surfaces, which allow the fast moisture-absorbing and desorbing polymer to be easily fixed. It is also possible to increase the surface area of the fixing surface, which is suitable for improving the rate of moisture absorption and release.

In addition, in a sorption type heat exchange module, the base material is preferably a metal with excellent thermal conductivity from the viewpoint of increasing heat exchange efficiency, and if the thermal conductivity is 50 W/m・K or more, , is preferable because it allows highly efficient heat exchange. Examples of such metals with excellent thermal conductivity include silver, copper, gold, aluminum, steel, etc. Among them, aluminum, aluminum alloys, copper, and copper alloys are more preferred from a practical point of view of price. preferable.

There is no particular limitation on the method for fixing the high-speed moisture absorbing and releasing polymer of the present invention to a substrate, and commonly used methods can be used as appropriate. Generally, a method is used in which a dispersion containing a high-speed moisture absorbing and desorbing polymer is attached to or immersed in a substrate, and then the dispersion medium is removed by drying or the like. Here, examples of the dispersion medium include water and organic solvents, and mixtures thereof can also be used. There are no limitations on the method of applying such a dispersion, and a coating method can generally be used. Among these, the coating method by impregnation is superior because it can reliably adhere to both sides and the center of the substrate at once.

Another method of fixing is to coat or soak the substrate with a solution containing a monomer that can be converted into a high-speed hygroscopic polymer by polymerization, and then to polymerize the monomer. This is a method of fixing a high-speed moisture absorbing and releasing polymer on the surface of the substrate. Here, examples of monomers that can be converted into a high-speed moisture absorbing and desorbing polymer through polymerization include the monomers described above in the explanation of the method for introducing carboxyl groups, and the crosslinking agents mentioned above. be able to.

There is no particular limit to the strength of fixing, but in general use of moisture absorbing and desorbing sheets fixed with fast moisture absorbing and desorbing polymers and sorption type heat exchange modules, it is possible to continuously absorb and desorb moisture for a long time. In many cases, the polymer is used for a long period of time, and in some cases, the fixed moisture absorbing and desorbing polymer is exposed to water due to dew condensation. Those that express are preferred. From this point of view, it is better to chemically bond to the base material or chemically bond through some kind of compound than to simply physically fix a high-speed moisture absorbing and desorbing polymer. Preferably, the moisture-absorbing and releasing polymers are bonded to each other, or the bonded product is chemically bonded to the base material.

There is no particular limitation on the form in which the above-mentioned moisture-absorbing and desorbing sheet is used, and it can be used in its sheet form or after being further molded. In particular, as a form that takes advantage of the high moisture absorption and desorption rate that is a characteristic of high-speed moisture absorption and desorption polymers, it is possible to make use of the high moisture absorption and desorption rate that is characteristic of high-speed moisture absorption and desorption polymers. Examples include laminates in which moisture-releasing sheets are laminated (for example, FIGS. 3, 5, 6, etc.), which can be suitably used as air-conditioning elements and the like. Such a laminate can have a large contact area with water vapor involved in moisture absorption and desorption, and can also be molded in such a way that pressure loss can be suppressed to a low level, which is advantageous from a practical point of view. Further, when constructing such a laminate, only the moisture-absorbing and desorbing sheets may be superimposed, or a sheet-shaped or molded material other than the moisture-absorbing and desorbing sheet may be inserted in the middle.

Specific examples of the laminate include a corrugated shape (wavy shape) as illustrated in FIG. 1, a honeycomb shape (square, hexagonal, octagonal, etc.) as illustrated in FIG. ), etc. In the corrugated type shown in Fig. 1, the moisture-absorbing and desorbing sheet 1 is continuously folded to produce a sheet having a large number of continuous peaks and valleys, and then the above-mentioned folding is performed on the surface of another flat sheet. It is manufactured by gluing or fusing the bottom of the troughs of the sheet. The obtained single-tiered sheets can be further stacked or rolled into a roll to be used as a laminate having a large number of holes. Note that both the foldable sheet and the flat sheet may be the moisture absorbing and releasing sheet 1, or only one of them may be the moisture absorbing and releasing sheet 1.

The above-described laminate can be incorporated into a dehumidifying or humidifying device and used as an air conditioning element such as a moisture absorbing and desorbing rotor that takes advantage of its moisture absorbing and desorbing performance. An example of such a device is a device having a system as shown in FIG. This system consists of a moisture absorbing and desorbing rotor 2, a motor 3 that rotates the rotor, a fan 9 that blows or sucks air, a heat source 8 for regeneration, etc., and by passing air as shown by the arrow, It dehumidifies or humidifies the air, making it possible to control the humidity of a predetermined area to a constant level.

Other specific examples include an air conditioning element in which single-tiered sheets are stacked in the same direction as shown in FIG. 5, or an air conditioning element in which single-tiered sheets are stacked in different directions as shown in FIG. The former air conditioning element can be used, for example, in a device that adjusts humidity by humidification and dehumidification by alternately performing humidification and dehumidification in a batch system as shown in FIG. By passing gases 4 and 6 with different humidity from different directions through each hole, moisture absorption and desorption occurs on the flat moisture absorbing and desorbing sheet 1 that separates each gas, and one gas is released from the other. Since moisture transfer to the gas, that is, latent heat exchange occurs, it can be used in latent heat exchange devices, etc.

Furthermore, the form of the sorption heat exchange module in the present invention is not particularly limited, and may be a sheet, a plate, a plate fin type, a corrugated fin type, a slit fin type, an Elofin tube type, or any other existing heat exchanger. Can be used without restriction as applicable. Among these, a corrugated fin type or an erofin tube type is preferable because they have high heat transfer efficiency and can be miniaturized.

The sorption heat exchange module of the present invention can be used as an adsorption heat pump, an adsorption heat storage system, etc. by utilizing heat generation during moisture absorption and heat absorption during moisture release. For example, an adsorption heat pump having a system as shown in FIG. 9 using an adsorber 13 made of an adsorption heat exchange module (also referred to as an adsorption core) as shown in FIG. 8 can be mentioned.

Here, FIG. 9 shows the process of repeating the operation of adsorbing the adsorbate (water vapor in this embodiment) onto the adsorbent and the operation of desorbing the adsorbate from the adsorbent using the heat of the hot water 18 from the heat exchanger. The adsorber 13 is a unit that cools the adsorption heat generated by the adsorbate operation with cooling water 17, and the cold water 20 obtained by evaporation of the adsorbate is taken out to the outside, and the generated adsorbate vapor is sent to the adsorber 13. The adsorbate vapor desorbed by the sending evaporator 14 and adsorber 13 is condensed by external cooling water 19, and the condensed adsorbate is supplied to the evaporator 14, and the warm heat obtained by condensing the adsorbate is This system configuration includes a condenser 15 that transfers the water to the cooling water 19 and discharges it to the outside.

The present invention will be specifically explained with reference to the following examples, but the present invention is not limited to the following examples. In addition, parts and percentages in the examples are based on weight unless otherwise specified. First, the evaluation method of each characteristic and the notation method of the evaluation results will be explained.

<Measurement of saturated moisture absorption rate>
A bone-dried high-speed moisture-absorbing and desorbing polymer is finely ground in a mortar to form a dry powder, which is used as a measurement sample. About 0.2 g of the polymer powder is dried in a hot air dryer at 105° C. for 30 minutes, and the weight is measured (Wd (g)). Next, the sample is left in a constant temperature and humidity chamber adjusted to a temperature of 20° C. and a relative humidity of 65% RH or 90% RH for 24 hours, and the weight of the sample that has absorbed moisture is measured (Ww (g)). Based on the above values, it was calculated using the following formula.
Saturated moisture absorption rate (weight%) = {(Ww-Wd)/Wd}×100

<Measurement of initial moisture absorption rate for 5 minutes>
A bone-dried high-speed moisture-absorbing and desorbing polymer is finely ground in a mortar to form a dry powder, which is used as a measurement sample. About 0.2 g of the polymer powder is dried in a hot air dryer at 105° C. for 30 minutes, and the weight is measured (Wd1 (g)). Next, the sample is left to stand for 5 minutes in a closed container adjusted to 75% RH at a temperature of 30° C. using the saturated salt method, and the weight of the sample that has absorbed moisture is measured (Ww1 (g)). Based on the above results, the initial moisture absorption rate for 5 minutes is calculated using the following formula.
Initial moisture absorption rate for 5 minutes ((g/g)/s) = {(Ww1-Wd1)/Wd1}/300

<Measurement of salt type carboxyl group amount>
First, approximately 1 g of a sufficiently dried sample was accurately weighed (W2 (g)), 200 ml of water was added to it, and then 1 mol/l hydrochloric acid aqueous solution was added while heating it to 50°C to adjust the pH to 2. . Obtain a titration curve using a 1 mol/l aqueous sodium hydroxide solution according to a conventional method. The amount of sodium hydroxide aqueous solution consumed by carboxyl groups (V2 (ml)) is determined from the titration curve, and the total amount of carboxyl groups (Aa (mmol/g)) is calculated using the following formula.
Aa (mmol/g)=0.1×V2/W2
Separately, a titration curve was obtained in the same manner without adjusting the pH to 2 by adding 1 mol/l aqueous hydrochloric acid solution during the measurement of the total amount of carboxyl groups described above, and the amount of H-type carboxyl groups (COOH) contained in the sample (Ab (mmol/g)). From these results, the amount of salt-type carboxyl groups is calculated using the following formula.
Salt type carboxyl group amount (mmol/g) = Aa - Ab

[Example 1]
A monomer mixture consisting of 80 parts of acrylonitrile (AN) and 20 parts of divinylbenzene and an oxidizing agent aqueous solution prepared by dissolving 4 parts of ammonium persulfate in 330 parts of water were added to a polymerization tank, and the temperature was raised to 65°C. Polymerize for 3 hours. The resulting polymer dispersion was centrifugally dehydrated to obtain a powdery acrylonitrile polymer.

450 parts of sodium hydroxide and 3,600 parts of water were added to 450 parts of the obtained powdered acrylonitrile polymer, and the reaction was carried out at 95°C for 60 hours to hydrolyze the nitrile groups and form carboxyl groups (hydrolyzed At the time of completion, it was converted to sodium salt form). The hydrolyzed polymer dispersion was adjusted to pH 10 with a 75% by weight aqueous sulfuric acid solution, washed by suction filtration, and centrifugally dehydrated to obtain a powdery hygroscopic polymer.

The obtained powdered moisture-absorbing and desorbing polymer was adjusted to pH 2 with a 75% by weight aqueous sulfuric acid solution, and after suction filtration, the pH was adjusted again to pH 10 with a 10% by weight aqueous tetramethylammonium hydroxide solution, thereby reducing the carboxyl content of the polymer. The group was converted to the tetramethylammonium (TMA) form. After desalting by suction filtration, washing, and centrifugal dehydration, the high-speed moisture absorbing and desorbing polymer of Example 1 was obtained. The properties of the obtained high-speed moisture absorbing and desorbing polymer are as shown in Table 1, and the saturated moisture absorption rate was 48% at 20° C. x 65% RH, indicating excellent moisture absorption. Further, it was confirmed that the initial moisture absorption rate for 5 minutes also showed a very excellent value.

[Example 2]
In the same manner as in Example 1, except that tetramethylammonium hydroxide was changed to 1,3-dimethylimidazolium iodide, Example 2 having a 1,3-dimethylimidazolium (DMI) salt type carboxyl group was prepared. A high-speed moisture absorption and desorption polymer was obtained. Although the saturated moisture absorption rate and initial 5-minute moisture absorption rate of the polymer were both inferior to those of Example 1, it was confirmed that the moisture absorption performance itself was very excellent. This is considered to be due to a decrease in the amount of carboxyl groups per unit weight and an increase in the hydrophobicity of the organic onium ion serving as the counter cation, compared to Example 1.

[Example 3]
In the same manner as in Example 1, except that tetramethylammonium hydroxide was changed to tetrabutylammonium bromide, the fast moisture absorbing and desorbing polymer of Example 3 having a tetrabutylammonium (TBA) salt type carboxyl group was obtained. Ta. Although both the saturated moisture absorption rate and the initial 5-minute moisture absorption rate of the polymer were slightly inferior to those of Example 1, it was confirmed that the moisture absorption performance itself was very excellent. This is considered to be due to the fact that the amount of carboxyl groups per unit weight was reduced compared to Example 1, and the number of carbon atoms in the organic onium ion serving as the counter cation was increased, resulting in increased hydrophobicity.

[Example 4]
In the same manner as in Example 1, except that tetramethylammonium hydroxide was changed to 1-ethylpyridinium bromide, the fast moisture absorbing and desorbing polymer of Example 4 having a 1-ethylpyridinium (EPY) salt type carboxyl group was produced. I got it. Although both the saturated moisture absorption rate and the initial 5-minute moisture absorption rate of the polymer were slightly inferior to those of Example 1, it was confirmed that the moisture absorption performance itself was very excellent. This is considered to be due to the fact that the amount of carboxyl groups per unit weight was reduced compared to Example 1, and the number of carbon atoms in the organic onium ion serving as the counter cation was increased, resulting in increased hydrophobicity.

[Comparative example 1]
A hygroscopic polymer of Comparative Example 1 having a 1-dodecylpyridinium (DPY) salt type carboxyl group was obtained in the same manner as in Example 1 except that tetramethylammonium hydroxide was changed to 1-dodecylpyridinium chloride. Ta. It was confirmed that the saturated moisture absorption rate and initial 5-minute moisture absorption rate of the polymer were both significantly inferior to those of Example 1, and the moisture absorption performance itself was also inferior. This is because the amount of carboxyl groups per unit weight was greatly reduced compared to Example 1, and the number of carbon atoms in the alkyl chain contained in the organic onium ion serving as the counter cation exceeds 10, resulting in a large hydrophobicity. This is thought to be due to the increase in

[Comparative example 2]
The moisture absorbing performance of the powdered moisture absorbing and releasing polymer produced in Example 1 was evaluated. Although the saturated moisture absorption rate of this polymer exceeded that of Example 1, it was confirmed that the initial moisture absorption rate for 5 minutes was significantly inferior. This is because the amount of carboxyl groups per unit weight increased compared to Example 1, but on the other hand, the ionic radius of the sodium ion serving as the counter cation is small and the electron density is high, so the ion dissociation is slow and the moisture absorption rate is low. It is thought that this has decreased.

[Comparative example 3]
A hygroscopic polymer of Comparative Example 3 having a potassium (K) salt type carboxyl group was obtained in the same manner as in Example 1, except that potassium hydroxide was used instead of tetramethylammonium hydroxide. Although the saturated moisture absorption rate of the polymer was almost the same as that of Example 1, the initial 5-minute moisture absorption rate was inferior to that of Example 1. This is considered to be because, compared to Example 1, potassium ions, which are counter cations, have a smaller ionic radius and a higher electron density than organic onium ions, and therefore ion dissociation is slower.

[Reference example 1]
The moisture absorption performance of Type A silica gel (manufactured by Hayashi Junyaku) was evaluated. It was confirmed that both the saturated moisture absorption rate and the initial 5-minute moisture absorption rate of Type A silica gel were inferior to those of Example 1.

As can be seen from Table 1, the high-speed moisture absorption and desorption polymer of the present invention has a saturated moisture absorption rate equivalent to that of Comparative Examples 2 and 3, which are conventional moisture absorption and desorption polymers, and a 5-minute It has an initial moisture absorption velocity.

1 Moisture absorption and release sheet 2 Moisture absorption and release rotor 3 Motor 4 High humidity gas to be dehumidified 5 Gas after dehumidification 6 Low humidity gas to be humidified 7 Gas after humidification 8 Heat source such as heater 9 Fan 10 Dehumidification/humidification area separation seal 11 Moisture absorption and release element Packed column 12 3-way valve 13 Adsorber 14 Evaporator 15 Condenser 16 Flow path switching valve 17 Cooling water 18 Hot water 19 Cooling water 20 Cold water

Claims (7)

An organic polymer containing 2.0 to 8.0 mmol/g of carboxyl groups whose countercation is an organic onium ion and having a crosslinked structure, wherein the organic onium ions are aliphatic ammonium ions, pyridinium ions, and imidazo at least one type selected from the group consisting of ion, all alkyl groups contained in the organic onium ion have 1 to 4 carbon atoms, and the organic onium ion contains 1 to 20 carbon atoms. A high-speed moisture absorbing and desorbing polymer. 2. The high-speed moisture absorbing and desorbing polymer according to claim 1, wherein the polymer is in the form of a fiber, particulate, or film. A fibrous structure containing the high-speed moisture absorption and desorption polymer according to claim 1 or 2 . A resin molded article containing the high-speed moisture absorption and desorption polymer according to claim 1 or 2 . An air conditioning element containing the high-speed moisture absorption and desorption polymer according to claim 1 or 2 , and having a plurality of gas passages. A sorption type heat exchange module, characterized in that the high speed moisture absorption and desorption polymer according to claim 1 or 2 is attached to at least a portion of the surface of the heat exchange module. An adsorption heat cycle comprising the high-speed moisture absorption and desorption polymer according to claim 1 or 2 as an adsorption core.

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