JP2002212374A - Hygroscopic composition, hygroscopic agent and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hygroscopic composition composed of a combination of a deliquescent substance having an excellent hygroscopic ability and a liquid absorbing resin absorbing and holding the deliquescent liquid of the deliquescent substance at a high level and capable of absorbing and holding the deliquescent liquid at a high level without liquefying during moisture absorption and a hygroscopic agent in a preferred form of use and to provide a method for producing the same. SOLUTION: This hygroscopic composition comprises the liquid absorbing resin which is a cross-linked polymer prepared by polymerizing a monomer consisting essentially of a cyclic N-vinyllactam and having >=20 g/g liquid absorption ratio of a saturated aqueous solution of calcium chloride at 25 deg.C and the solid deliquescent substance. One of the hygroscopic agent is a hygroscopic agent comprising the liquid absorbing resin and the solid deliquescent substance. The liquid absorbing resin is the cross-linked polymer obtained by polymerizing the monomer component consisting essentially of the cyclic N-vinyllactam, has >=20 g/g liquid absorption ratio of the saturated aqueous solution of calcium chloride at 25 deg.C and is mixed with the solid deliquescent substance and packaged with a packaging material. The packaging material is characterized in that at least a part thereof is a moisture-permeable film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a hygroscopic composition, a hygroscopic agent, and a method for producing a hygroscopic agent.

[0002]

2. Description of the Related Art Deliquescent substances such as calcium chloride and magnesium chloride have been used in various applications such as dehumidifiers, dew condensation preventives, desiccants or humectants utilizing their excellent moisture absorbing ability. However, calcium chloride, magnesium chloride, etc. deliquesce upon absorption of moisture and become liquid. Therefore, when a container or the like is damaged, there is a problem that the deliquescent liquid leaks and contaminates the surroundings. Therefore, means for preventing leakage by increasing the viscosity or absorbing or gelling the deliquescent solution are being studied. For example, a water-soluble polymer such as polyvinyl alcohol, sodium polyacrylate or polyacrylamide is blended. (Japanese Patent Application Laid-Open No. 52-10 / 1982)
No. 7042, JP-A-60-143819, JP-A-63
252524), a water-absorbing modified polyethylene oxide resin, a crosslinked α-modified starch, a cationic water-absorbing resin, or a water-absorbing resin such as an acrylamide-acrylic acid (salt) cross-linked copolymer. Method for preventing liquefaction by liquid / gelation (JP-A-61-2
00835, JP-A-63-31522, JP-A-3-31
No. 127610, JP-A-4-78415, JP-A-11
No. -221428) and the like are disclosed.

[0003]

As described above, as a means for preventing the deliquescent liquid from leaking, a method using a water-soluble polymer or a water-absorbing resin is known. However,
When using a water-soluble polymer to prevent liquefaction,
There is a risk that tackiness or stickiness may occur during moisture absorption, liquefaction of the deliquescent substance may not be prevented, and liquefaction may occur together. On the other hand, when a water-absorbing resin is used to prevent liquefaction, there are also the following problems.

[0004] The water-absorbing resins are roughly classified into three types: anionic group-containing type, cationic group-containing type and nonionic group-containing type. When an anionic group-containing water-absorbing resin used for diapers or the like or a cationic group-containing water-absorbing resin is used, the liquid absorption ratio is low or the liquid absorption ratio is reduced, and thus deliquescent calcium chloride is used. However, there is a possibility that the high-concentration electrolyte-containing aqueous solution cannot be sufficiently absorbed and retained. The cause is presumed to be that the water absorbing ability of the anionic or cationic group-containing water absorbing resin depends on the osmotic pressure. That is, when the salt (ion) concentration of the liquid increases, the difference (osmotic pressure difference) from the salt (ion) concentration in the water-absorbent resin disappears, and the liquid absorption ratio decreases. In particular, since deliquescence such as calcium chloride is close to a saturated aqueous solution, these water absorbing resins hardly absorb liquid.

When a nonionic group-containing water-absorbent resin is used, a larger amount of a high-concentration aqueous electrolyte solution can be absorbed than an anionic or cationic group-containing water-absorbent resin.
Although various studies have been made, the liquid absorbing ability is still insufficient, and further improvement is expected. The liquid absorbing ability of the nonionic group-containing water-absorbing resin is based on the affinity of the nonionic hydrophilic group with the aqueous solution, and the liquid absorption ratio is affected by the type and concentration of the electrolyte as compared with the anionic and cationic water-absorbing resins. It is said to be difficult. However, it has not yet been found that even with a (co) polymer of various nonionic group-containing monomers, a solution capable of absorbing a saturated-concentration electrolyte-containing aqueous solution such as a saturated calcium chloride aqueous solution by 20 times or more can be obtained. Crosslinked polyethylene oxide shown in Comparative Example, N-
Cross-linked vinyl acetamide polymers, cross-linked acrylamide polymers and the like are examples. Further, there was almost no knowledge about the liquid absorbing ability of the water-absorbing resin in the saturated concentration region.

Accordingly, an object of the present invention is to provide a combination of a deliquescent substance having excellent moisture absorbing ability and a liquid-absorbent resin which absorbs and retains the deliquescent liquid of the deliquescent substance at a high level, and liquefies when absorbing moisture. It is an object of the present invention to provide a hygroscopic composition capable of absorbing and maintaining a high level of deliquescent liquid without any problem, a hygroscopic agent which is a preferred use form thereof, and a method for producing the same.

[0007]

Means for Solving the Problems As a result of diligent studies, the present inventors have found that a crosslinked polymer obtained by polymerizing a monomer component containing cyclic N-vinyllactam as a main component can be used as a saturated calcium chloride aqueous solution or the like. It has been found that an aqueous solution containing a high-concentration polyvalent metal salt can be highly absorbed and retained. According to such knowledge, the above-mentioned objects are a crosslinked polymer obtained by polymerizing a monomer component containing cyclic N-vinyllactam as a main component as a liquid-absorbing resin as a means for preventing the deliquescent liquid from leaking. The absorption capacity of a saturated aqueous solution of calcium chloride at 25 ° C. is 20 g /
g of the liquid-absorbent resin and a combination of the liquid-absorbent resin and a solid deliquescent substance. Further, the above is achieved by mixing the specific liquid-absorbent resin with a solid deliquescent substance and packaging at least a part thereof with a packaging material that is a moisture-permeable film. further,
This is achieved by arranging the specific liquid-absorbent resin and the solid deliquescent substance so as to come into contact with the liquid-absorbent resin when the solid deliquescent substance becomes liquid by absorbing moisture and deliquescent.

That is, the hygroscopic composition according to the present invention is a crosslinked polymer obtained by polymerizing a monomer component mainly composed of cyclic N-vinyllactam, and absorbs a saturated calcium chloride aqueous solution at 25 ° C. It comprises a liquid-absorbent resin having a liquid magnification of 20 g / g or more and a solid deliquescent substance. Further, the hygroscopic agent according to the present invention is a hygroscopic agent containing a liquid absorbing resin and a solid deliquescent substance, wherein the liquid absorbing resin is a monomer having a cyclic N-vinyl lactam as a main component. A crosslinked polymer obtained by polymerizing the components, wherein the absorption capacity of a saturated calcium chloride aqueous solution at 25 ° C. is 20 g / g or more, and mixed with the solid deliquescent substance;
It is packaged with a packaging material, wherein the packaging material is at least partially a moisture-permeable film.

Further, the method for producing a moisture absorbent according to the present invention is a method for producing a moisture absorbent containing a liquid absorbent resin and a solid deliquescent substance, wherein the liquid absorbent resin is a cyclic N-vinyl resin. A crosslinked polymer obtained by polymerizing a monomer component containing a lactam as a main component, wherein the absorption capacity of a saturated calcium chloride aqueous solution at 25 ° C. is 20 g / g or more; Mixing and packaging with a packaging material, wherein the packaging material is at least partially a moisture-permeable film. The moisture absorbent according to the present invention is a moisture absorbent containing a liquid absorbent resin and a solid deliquescent substance,
The liquid-absorbent resin is a crosslinked polymer obtained by polymerizing a monomer component containing cyclic N-vinyllactam as a main component, and has a liquid absorption capacity of a saturated calcium chloride aqueous solution at 25 ° C. of 20 g / g or more. The solid deliquescent material is arranged so as to be in contact with the liquid-absorbent resin when the solid deliquescent material is deliquescent by absorption of moisture.

[0010] The method for producing a moisture absorbent according to the present invention is a method for producing a moisture absorbent containing a liquid absorbent resin and a solid deliquescent substance, wherein the liquid absorbent resin is a cyclic N-vinyl resin. A crosslinked polymer obtained by polymerizing a monomer component containing lactam as a main component, wherein the liquid absorption capacity of a saturated calcium chloride aqueous solution at 25 ° C. is 20 g / g or more, and the solid deliquescent substance is Is arranged so as to come into contact with the liquid-absorbent resin when the liquid is absorbed and deliquescent.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The solid deliquescent substance used in the present invention includes various substances. For example, lithium chloride, sodium chloride, potassium chloride, calcium chloride, magnesium chloride, sulfuric acid Examples include manganese, magnesium sulfate, lithium bromide, sodium bromide, potassium bromide, calcium bromide, magnesium bromide, sodium hydroxide, potassium hydroxide, calcium hydroxide and the like. Among them, lithium chloride, calcium chloride and magnesium chloride are preferred. A crosslinked (co) polymer obtained by polymerizing the solid deliquescent material and a monomer component containing cyclic N-vinyllactam as a main component,
The absorption capacity of a saturated calcium chloride aqueous solution at 20 ° C. is 20
The mixing ratio and use ratio with the liquid-absorbing resin of g / g or more may be appropriately selected in consideration of the liquid-absorbing ability of the liquid-absorbing resin, the type of the deliquescent substance, the conditions of the atmosphere used, and the like.

For example, an anhydrous calcium chloride is used as a solid deliquescent substance, a resin having an absorption capacity of a saturated calcium chloride aqueous solution of 30 g / g is used as a liquid-absorbing resin, and under conditions of the atmosphere used. When the concentration of the deliquescent liquid becomes 45% by weight when the anhydrous calcium chloride is deliquescent-absorbed, the deliquescent substance 1 is added to 1 part by weight of the liquid-absorbent resin.
It is preferable to mix and use 3.5 parts by weight because the liquid-absorbing resin sufficiently exhibits its liquid-absorbing ability.
That is, the following formula (1) is used for 1 part by weight of the liquid absorbing resin.
It is preferable to include a solid deliquescent substance in an amount equal to or less than the amount calculated from. Calculation formula (1): Amount of deliquescent substance (parts by weight) = deliquescence concentration of deliquescent substance (% by weight) x liquid absorption ratio of liquid absorbent resin (g /
g) The liquid-absorbent resin used in the present invention needs to be a crosslinked (co) polymer obtained by polymerizing a monomer component containing cyclic N-vinyllactam as a main component.

The proportion of the cyclic N-vinyllactam in all the monomers (excluding the crosslinkable monomer) used in producing the crosslinked (co) polymer is 80 mol% or more, preferably 90 mol%.
1% or more, more preferably 100 mol%. 80
If the proportion of the cyclic N-vinyl lactam is smaller than mol%, the salt resistance, that is, the ability to absorb a high concentration polyvalent metal salt-containing aqueous solution becomes small. Examples of the cyclic N-vinyl lactam used in the present invention include, but are not particularly limited to, N-vinyl-2-pyrrolidone and N-vinyl caprolactam. These cyclic N
-Only one kind of vinyl lactam may be used, or two or more kinds may be used in combination. Among them, from the viewpoint of the safety of the monomer and the obtained liquid absorbing resin, N-vinyl-
2-Pyrrolidone is particularly preferred.

As the monomer copolymerizable with the cyclic N-vinyl lactam, any unsaturated monomer compatible with and copolymerized with the cyclic N-vinyl lactam can be used. As the unsaturated monomer, for example, acrylic acid,
Methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, citraconic acid, vinyl sulfonic acid, (meth)
Allylsulfonic acid, 2- (meth) acrylamide-2-
Methylpropanesulfonic acid, 2- (meth) acryloylethanesulfonic acid, 2- (meth) acryloylpropanesulfonic acid, and alkali metal salts and ammonium salts of these monomers; N, N-dimethylaminoethyl (meth) acrylate And quaternary compounds thereof; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide, diacetone (meth) acrylamide, N-isopropyl (meth) acrylamide, (meth) acryloyl (Meth) acrylamides such as morpholine and derivatives of these monomers; hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; polyethylene glycol mono ( (T) polyalkylene glycol mono (meth) acrylates such as acrylate, polypropylene glycol mono (meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate, and methoxypolypropylene glycol mono (meth) acrylate; N-vinyl monomer such as N-vinyl succinimide N-vinylformamide, N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-
N-vinylamide monomers such as N-methylacetamide;
Vinyl methyl ether; and the like, but is not particularly limited thereto. These ethylenically unsaturated monomers are
Only one type may be used, or two or more types may be used in combination.

As a method for obtaining the crosslinked (co) polymer,
Bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization,
Various methods such as a precipitation polymerization method can be employed.
The concentration of the monomer component in the aqueous solution prepared in the preceding stage is 2
5% by weight or more, preferably 25% by weight or more and 80% by weight
Within the following range. If the concentration of the monomer component is less than 25% by weight, a crosslinked liquid-absorbent resin cannot be obtained, and the obtained resin may be dissolved in water or the like. Further, even when a crosslinked liquid-absorbent resin is obtained, it is difficult to break down the gel after polymerization. Further, a long time is required for drying, and the resin may be deteriorated during drying. on the other hand,
If the concentration of the monomer component exceeds 80% by weight, it becomes difficult to control the polymerization, and it may not be possible to obtain a liquid-absorbent resin having excellent liquid-absorbing performance.

In order to obtain the crosslinked (co) polymer, a method of polymerizing in the presence of a crosslinking agent, a method of crosslinking after polymerization, and the like can be adopted. When the polymerization is carried out in the presence of a crosslinking agent, the amount of the crosslinking agent used can be appropriately set depending on the polymerization conditions, the type of the monomer component, and the like. Within the range, preferably within the range of 0.03 to 1 mol%. If the amount of the crosslinking agent is less than 0.01 mol%, a crosslinked (co) polymer may not be obtained and may be dissolved in water. 5mol%
If it is larger than this, the expansion of the molecular chain is restricted more than necessary, and the liquid absorbing performance becomes small.

Means for initiating polymerization of the monomer component containing cyclic N-vinyl lactam as a main component include a method of adding a polymerization initiator, a method of irradiating UV, a method of applying heat,
A method of irradiating light in the presence of a photoinitiator or the like can be employed. Examples of the method of crosslinking after polymerization include a method of irradiating N-vinylpyrrolidone-based polymer with UV, a method of applying heat to the N-vinylpyrrolidone-based polymer to cause self-crosslinking, and a method of N-vinylpyrrolidone-based polymer. After containing a radical generator, a method of self-crosslinking by applying heat, after including a radical polymerizable crosslinking agent and a radical polymerization initiator in the N-vinyl lactam polymer,
Examples of the method include heating and / or light irradiation.

The N-vinyllactam-based polymer used in the methods (1) and (2) is prepared by polymerizing a monomer component containing an N-vinyllactam-based monomer by a conventionally known polymerization method, for example, bulk polymerization, solution polymerization, emulsion polymerization, It can be obtained by performing suspension polymerization, precipitation polymerization or the like. In the method, the method of adding a radical polymerization initiator to the obtained N-vinyllactam-based polymer is not particularly limited. For example, a radical polymerization initiator may be added to the reaction solution immediately after obtaining the N-vinyllactam-based polymer. An agent may be added, or instead of the above-mentioned reaction solution, a product obtained by drying a vinyllactam-based polymer to obtain powder or the like may be used.

The radical polymerization initiator used in the method is not particularly limited as long as it generates a radical molecule by heat or light. Among the polymerization initiators for obtaining the N-vinyllactam-based polymer described above, Photopolymerization catalysts such as benzoin ether can be used in addition to azo compounds, peroxides, and redox initiators. Of these, peroxides are particularly preferable because they form a crosslinked product having higher shape retention. Specific examples of peroxides other than those described above include:
t-butyl peroxypivalate, octanoyl peroxide, succinic peroxide, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyiso Butyrate, t-butylperoxymaleic acid, and the like, but are not limited thereto. There is no particular limitation on the amount of the radical polymerization initiator used.
The content is preferably 0.005 to 20% by weight based on the total amount of the vinyl lactam polymer and the radical polymerizable crosslinking agent,
5 to 5% by weight is more preferred.

The radical polymerizable crosslinking agent used in the method may be a compound having two or more ethylenically unsaturated groups in one molecule, and is limited in molecular weight and molecular structure other than the unsaturated group. is not. Specific examples of the radical polymerizable crosslinking agent include ethylene glycol di (meth) acrylate and polyethylene glycol di (meth)
Acrylate, trimethylolpropane tri (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, pentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, allyl (Meth) acrylic crosslinking agents such as (meth) acrylate, (meth) acrylamide crosslinking agents such as N, N'-methylenebisacrylamide, N, N'-divinyl-2-imidazolidinone, N, N'- 1,4-butylenebis (N-vinylacetamide), divinylbenzene,
Vinyl crosslinkers such as divinyltoluene, diallylamine, triallylamine, tetraallyloxyethane, triallyl cyanurate, triallyl isocyanurate, diallyl ether, ethylene glycol diallyl ether, polyethylene glycol diallyl ether, trimethylolpropane triallyl ether, allyl Allyl cross-linking agents such as sulfide, allyl disulfide, diallyl urea, triallyl trimellitate, diallyl dimethyl ammonium chloride, sodium diallyl oxalate, and diallyl esters of polybasic acids such as diallyl phthalate and diallyl succinate. Among these crosslinking agents, (meth) acrylic and (meth) acrylamide-based crosslinking agents are preferable because of their good reactivity with vinyllactam-based polymers.

In crosslinking the N-vinyllactam-based polymer by the method (1), an arbitrary solvent may be used in the composition. As the solvent at this time, a solvent that can be used to obtain an N-vinyllactam-based polymer can be used.
It is preferable to use a solvent that makes the composition homogeneously dissolved. Since the crosslinked product obtained from the composition of the present invention can absorb a solvent in a wide pH range, there is no limitation on the types and amounts of acids and bases contained in the solvent. In the case of crosslinking by irradiating UV or light in the method and the method, a photopolymerization initiator or a sensitizer may be used.

When the N-vinyl lactam polymer is crosslinked by the method (1), a monofunctional monomer, a dye, an aromatic agent, a filler, a buffer,
An inorganic salt or the like may be mixed. When the method is described in detail, an N-vinyl lactam polymer is heated in an oven or the like.
It is obtained by heating by a conventionally known method.
The heating conditions are not particularly limited.
It is preferable to heat at a temperature of 50 to 250 ° C. for 1 to 120 minutes. If the heating temperature is too high or the heating time is too long, the obtained resin may be colored.On the other hand, if the heating temperature is too low or the heating time is too short, self-crosslinking hardly proceeds, and May be insufficient.

The method will be described in detail. It can be obtained by adding a radical generator to an N-vinyl lactam polymer and then heating it by a conventionally known method such as oven heating. The radical generator used in the method is not particularly limited as long as it is a compound capable of generating a radical by heat. For example, persulfates such as potassium persulfate and ammonium persulfate; alkyl peroxides, peroxyketals And the like; azo compounds such as azobisisobutyronitrile; and the like. The heating conditions are not particularly limited, for example, 120 to
It is preferable to heat at a temperature of 280 ° C. for 1 to 30 minutes. If the heating temperature is too high or the heating time is too long, the obtained resin may be colored.On the other hand, if the heating temperature is too low or the heating time is too short, self-crosslinking hardly proceeds, and May be insufficient.

The amount of the soluble component contained in the crosslinked (co) polymer is preferably 30% by weight or less, more preferably 20% by weight or less. If the amount of the soluble component exceeds 30% by weight, the soluble component may be dissolved in the deliquescent liquid and the absorption capacity may be gradually reduced. Crosslinking (co) obtained in this way
The polymer has excellent liquid absorbency with respect to a high-concentration electrolyte aqueous solution, in which the absorption capacity of a saturated calcium chloride aqueous solution at 25 ° C. is 20 g / g or more. The hygroscopic composition comprising the liquid absorbing resin and a solid deliquescent material,
It has excellent hygroscopicity and does not liquefy even if it absorbs moisture.

The method for producing a hygroscopic agent of the present invention is a cross-linked polymer obtained by polymerizing a solid deliquescent substance and a monomer component containing cyclic N-vinyllactam as a main component.
Absorption capacity of saturated aqueous calcium chloride solution at 20 g
/ G or more, wherein the liquid-absorbent resin is disposed so as to be in contact with the liquid-absorbent resin when the deliquescent substance becomes liquid by absorbing moisture and deliquescent. . A solid deliquescent substance used in the method for producing a moisture absorbent of the present invention, and a crosslinked polymer obtained by polymerizing a monomer component mainly composed of cyclic N-vinyllactam at 25 ° C Examples of the liquid-absorbent resin having a saturated calcium chloride aqueous solution having a liquid absorption capacity of 20 g / g or more include those similar to those used in the above-mentioned hygroscopic composition.

The deliquescent substance needs to be arranged so as to come into contact with the liquid-absorbent resin when the deliquescent substance becomes liquid by absorbing moisture. The moisture absorbent of the present invention is a moisture absorbent containing a liquid absorbent resin and a solid deliquescent substance, and is a crosslinked polymer obtained by polymerizing a monomer component mainly composed of cyclic N-vinyl lactam. In this case, a liquid absorbing resin having a liquid absorption capacity of a saturated calcium chloride aqueous solution at 25 ° C. of 20 g / g or more and a solid deliquescent substance are mixed and packaged with a moisture-permeable film.

Examples of the method for producing the moisture absorbent of the present invention include:
A crosslinked polymer obtained by polymerizing a solid deliquescent substance and a monomer component containing cyclic N-vinyllactam as a main component, and having a liquid absorption capacity of a saturated calcium chloride aqueous solution at 25 ° C. of 20 g / g. The above-mentioned liquid-absorbent resin is mixed with the moisture-absorbent composition, and the resultant is packaged in a moisture-permeable film. FIG. 4 shows this manufacturing method as [Example 1 of hygroscopic agent]. Another desiccant according to the present invention is a desiccant containing a liquid-absorbent resin and a solid deliquescent substance. A crosslinked polymer obtained by polymerizing a monomer component containing vinyl lactam as a main component and having a liquid absorption capacity of a saturated calcium chloride aqueous solution at 25 ° C. of 20 g / g or more so as to be in contact with an absorbent resin; It is arranged.

As another example of the method for producing a moisture absorbent of the present invention, a perforated plate is placed after a liquid-absorbent resin is placed in a container, and a solid deliquescent liquid is placed on the perforated plate. Place the substance. Thereafter, the container is covered with a moisture-permeable film. In this way, the deliquescent substance and the liquid-absorbent resin are arranged to obtain a moisture absorbent. In this way, when the deliquescent substance deliquesces and liquefies, the deliquescent liquid flows down from the hole of the perforated plate and comes into contact with the liquid-absorbent resin, and the liquid-absorbent resin absorbs the deliquescent liquid with the liquid-absorbing gel To prevent liquefaction. In addition, in this way, it is understood that all the deliquescent substances on the perforated plate are not deliquescent and liquefied, so that the moisture absorbing ability is lost. FIG. 5 shows this manufacturing method as [Example 2 of hygroscopic agent].

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments. [Production Example 1] First, N-vinyl-2-pyrrolidone (Mw:
111.1) 150.07 parts by weight, 0.168 parts by weight of triallyl cyanurate (Mw: 249.27) (reagent / manufactured by Wako Pure Chemical Industries, Ltd.), and 346.
58 parts by weight were put in a 500 ml separable flask and mixed to prepare an aqueous solution of a monomer component. In the above aqueous solution, the monomer component is N-vinyl-2-pyrrolidone 100 m
ol%, and the concentration of the monomer component is 30% by weight.
And contained a crosslinking agent, ie, triallyl cyanurate in an amount of 0.05 mol% (based on the monomer component).

After nitrogen was blown into this aqueous solution to reduce the dissolved oxygen in the aqueous solution to 0.1 ppm or less, the flask was placed in a water bath and the temperature of the aqueous monomer solution was adjusted to 50 ° C. Then, 3.38 parts by weight of a 10% by weight aqueous solution of 2,2′-azobis (2-amidinopropane) dihydrochloride (V-50 / manufactured by Wako Pure Chemical Industries, Ltd.) was added as a polymerization initiator, and the mixture was added for 30 seconds. After stirring, the stirring was stopped and the mixture was allowed to stand. The polymerization started 3 minutes after the addition of the polymerization initiator, and reached a peak 35 minutes later. The temperature at that time was 100 ° C. After aging for 20 minutes after the peak, the polymer gel was taken out of the flask. It was a clear gel.

This gel is W3 × D3 × H3 mm with scissors.
It was cut into small pieces and dried with hot air at 120 ° C. for 3 hours (Perfect Oven PS-112 / made by Tabai). After drying, a yellowish-white resin is obtained, which is pulverized with a table-top small pulverizer (Sample Mill SK-M10 / Kyoritsu Riko Co., Ltd.), and classified with a sieve having openings of 1000 μm and 500 μm. 500 μm through a 1000 μm sieve
m, a liquid-absorbent resin (1) having a particle size remaining on the sieve was obtained. [Production Example 2] In a 1-L flask equipped with a stirring blade, a monomer supply tank, a thermometer, a cooling pipe, and a nitrogen gas introduction pipe,
Add 800 g of water, introduce nitrogen gas, and stir,
The flask was heated so that the temperature in the flask became 75 ° C. In this flask, 200 g of N-vinylpyrrolidone, and 2,
2'-azobis (2-amidinopropane) dihydrochloride
06 g was fed into the system over 60 minutes and polymerized.
After heating at the same temperature for 2 hours, the internal temperature was raised to 90 ° C,
The polymerization was completed by heating for further 30 minutes to obtain an aqueous solution of polyvinylpyrrolidone. The nonvolatile content of the obtained aqueous solution of polyvinylpyrrolidone was 19.9%.

The obtained aqueous solution of polyvinylpyrrolidone was treated with 1
It was dried at 20 ° C. for 1 hour and further pulverized to obtain a polyvinylpyrrolidone powder. The obtained polyvinylpyrrolidone powder was placed in a hot air drier and heated at 200 ° C. for 30 minutes to obtain a liquid-absorbent resin (2). [Production Example 3] The polyvinylpyrrolidone powder obtained in Production Example 2 was placed in a hot air drier and heated at 180 ° C for 120 minutes to obtain a liquid-absorbent resin (3). [Comparative Production Example 1] First, 40% by weight of acrylamide (M
w: 71.04) Aqueous solution (manufactured by Mitsui Toatsu Chemicals, Inc.) 1
7.7.6 parts by weight, 5.14 parts by weight of a 1.5% by weight aqueous solution of N, N'-methylenebisacrylamide (Mw: 154.17) (TRIAM-507 / Wako Pure Chemical Industries, Ltd.), and deionization 97.42 parts by weight of water was put in a 500 ml separable flask and mixed to prepare an aqueous solution of a monomer component. In the above aqueous solution, the monomer component contains acrylamide at 100 mol%, the concentration of the monomer component is 25% by weight, and the crosslinking agent, ie, N, N ′
-Methylene bisacrylamide contained 0.05 mol% (based on monomer components).

After nitrogen was blown into the aqueous solution to reduce the dissolved oxygen in the aqueous solution to 0.1 ppm or less, the flask was placed in a water bath to adjust the temperature of the aqueous monomer solution to 25 ° C. Then, a 10% by weight aqueous solution of sodium persulfate (reagent / manufactured by Katayama Chemical Industry Co., Ltd.) was used as a polymerization initiator.
Then, 2.0 parts by weight of a 1% by weight aqueous solution of L-ascorbic acid (reagent / manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred for 30 seconds, stopped stirring, and allowed to stand.
The polymerization started 10 minutes after the addition of the aqueous L-ascorbic acid solution, and the polymerization reached a peak 44 minutes later. The temperature at that time was 85.5 ° C. After aging for 20 minutes after the peak, the polymer gel was taken out of the flask. It was a clear gel.

The gel was W3 × D3 × H3 mm with scissors.
The pieces were cut into small pieces, and dried with hot air at 120 ° C. for 3 hours (Perfect Oven PS-112 / manufactured by Tabai Espec Corporation). After drying, a yellowish-white resin was obtained, which was then crushed with a table-top small crusher (Sample Mill SK-M10 /
(Commercially available from Kyoritsu Riko Co., Ltd.), and classified by a sieve having openings of 1000 μm and 500 μm. The comparative liquid-absorbent resin (1) having a particle size that passes through a 1000 μm sieve and remains on a 500 μm sieve is obtained. Obtained. [Comparative Production Example 2] First, 40% by weight of acrylamide (M
w: 71.04) Aqueous solution (manufactured by Mitsui Toatsu Chemicals, Inc.) 1
24.3 parts by weight, 100% acrylic acid (Mw: 72.0
6) 21.6 parts by weight (manufactured by Nippon Shokubai Co., Ltd.), 25.0 parts by weight of a 48% by weight aqueous solution of sodium hydroxide (Mw: 40.0) (manufactured by Kayaku Co., Ltd.), N, N'-methylenebis Acrylamide (Mw: 154.17) (TRIAM-
507 / manufactured by Wako Pure Chemical Industries, Ltd.), 10.28 parts by weight of a 1.5% by weight aqueous solution and 74.59 parts by weight of deionized water were placed in a 500 ml separable flask and mixed to obtain an aqueous solution of the monomer component. Prepared. In the above aqueous solution, the monomer component contains 70 mol% of acrylamide and 30 mol% of sodium acrylate, the concentration of the monomer component is 30% by weight, and the crosslinking agent, ie, N, N′-methylene 0.1 mol% of bisacrylamide
(Relative to the monomer component).

After nitrogen was blown into the aqueous solution to reduce the dissolved oxygen in the aqueous solution to 0.1 ppm or less, the flask was placed in a water bath to adjust the temperature of the aqueous monomer solution to 20 ° C. Then, a 10% by weight aqueous solution of sodium persulfate (reagent / manufactured by Katayama Chemical Industry Co., Ltd.) was used as a polymerization initiator.
Then, 2.0 parts by weight of a 1% by weight aqueous solution of L-ascorbic acid (reagent / manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred for 30 seconds, stopped stirring, and allowed to stand.
The polymerization started 3 minutes after the addition of the aqueous L-ascorbic acid solution, and the polymerization reached a peak 44 minutes later. The temperature at that time was 100 ° C. After aging for 20 minutes after the peak, the polymer gel was taken out of the flask. It was a clear gel.

This gel was W3 × D3 × H3 mm with scissors.
The pieces were cut into small pieces and dried with hot air at 160 ° C. for 3 hours (Perfect Oven PS-112 / made by Tabai). After drying, a yellowish-white resin is obtained, which is pulverized with a table-top small pulverizer (Sample Mill SK-M10 / Kyoritsu Riko Co., Ltd.), and classified with a sieve having openings of 1000 μm and 500 μm. 500 μm through a 1000 μm sieve
m, a comparative liquid-absorbent resin (2) having a particle size remaining on the sieve was obtained. [Comparative Production Example 3] 800 g of water was put into a 1-L flask equipped with a stirring blade, a monomer supply tank, a thermometer, a cooling pipe, and a nitrogen gas introduction pipe, nitrogen gas was introduced, and the inside temperature of the flask was stirred. Was heated to 75 ° C. In this flask, 200 g of N-vinylpyrrolidone and 0.06 g of 2,2′-azobis (2-amidinopropane) dihydrochloride were supplied into the system over 60 minutes, and polymerized. After heating at the same temperature for 2 hours, the internal temperature was raised to 90 ° C., and further heated for 30 minutes to complete the polymerization to obtain an aqueous solution of polyvinylpyrrolidone. The nonvolatile content of the obtained aqueous solution of polyvinylpyrrolidone was 19.9%.

The obtained aqueous solution of polyvinylpyrrolidone was diluted with 1
It was dried at 20 ° C. for 1 hour and further pulverized to obtain a polyvinylpyrrolidone powder. The obtained polyvinylpyrrolidone powder was placed in a hot air drier and heated at 200 ° C. for 60 minutes to obtain a comparative liquid-absorbent resin (5). [Comparative Production Example 4] The polyvinylpyrrolidone powder obtained in Comparative Production Example 3 was placed in a hot air drier and heated at 190 ° C for 120 hours.
After heating for 5 minutes, a comparative liquid-absorbent resin (6) was obtained. [Method of Measuring Liquid Absorption Ratio] (Preparation of Saturated Calcium Chloride Aqueous Solution (Absorbed Liquid)) 120 g of anhydrous calcium chloride and 137.5 g of deionized water were added, stirred and dissolved while cooling.
And then stirring was continued for 3 hours. Since some calcium chloride remained without being dissolved, the supernatant was used as a liquid to be absorbed.

(Liquid Absorbing Operation) Two nonwoven fabrics of 5 cm × 5 cm that can be heat-sealed were prepared. A portion 1 mm from the rear end of the two sheets was heat-sealed, and three of the four sides were bonded to form a bag. Then, 0.3 g of the liquid-absorbent resin was put therein and heat-sealed to prevent the liquid-absorbent resin from spilling out. 250 g of the prepared saturated calcium chloride aqueous solution was placed in a PP container having an inner diameter of 6 cm and a depth of 10 cm. Thereafter, the bag containing the liquid-absorbent resin was immersed, sealed with a stirrer chip, stirred for 5 hours with a stirrer, and then the immersed bag with the liquid-absorbent resin was pulled up.

(Draining operation) Two kitchen towels (made by Oji Paper) were cut off. 4 times each 6cm × 6
cm. One of them was placed on a table, and a bag with a liquid-absorbent resin was put on the table, and another folded kitchen towel was put on the bag. A weight of 20 g / cm ² was placed thereon and drained for 20 seconds. After draining, the weight of the bag containing the absorbent resin was measured. (W
1 g) As a blank test, the same operation was performed without adding the absorbent resin, and the weight of the bag was measured. (W2g) Liquid absorption capacity (g / g) = (W1g-W2g) /0.3g [Evaluation method 1 for moisture absorption state] As shown in FIG. 1, 1 part by weight of a liquid absorbing resin and 9 parts by weight of calcium chloride were added. The beaker (container 2) containing the mixed hygroscopic composition was placed in a container (container 1) containing water, sealed with a lid, and placed in a thermostat adjusted to 25 ° C.

The state of the hygroscopic composition was observed at predetermined time intervals. [Evaluation Method 2 for Moisture Absorption State] As shown in FIG. 2, 9 parts by weight of calcium chloride and 1 part by weight of a liquid absorbing resin were placed in a container. That is, after the liquid-absorbent resin was put in the container, a perforated plate was set, and solid calcium chloride was placed on the perforated plate. Thereafter, the container was covered with a moisture-permeable film. The container was placed in a thermo-hygrostat adjusted to 25 ° C. and a relative humidity of 95%, and the state was observed at predetermined time intervals. Table 3 shows the results.
It was shown to. [Method of measuring liquid absorption rate] 45 in a 100 ml beaker
A 50% by weight aqueous solution of calcium chloride and a stirrer chip (length: 4 cm) are charged, and the liquid absorbent resin 2 is stirred while stirring.
0 g was added, and the time (second) until gelation was measured. The results are shown in [Reference Table].

[Examples 1 to 3] The absorbency of the liquid-absorbent resins (1) to (3) obtained in Production Examples 1 to 3 was measured with an aqueous calcium chloride solution adjusted to a predetermined concentration. The results are shown in Table 1 and FIG. As is evident from the results, the liquid-absorbent resin of the present invention has a remarkably excellent liquid-absorption ratio in a liquid in which calcium chloride (deliquescent substance) is deliquescent due to moisture absorption, that is, in a saturated concentration region (45% by weight in this case). I have. [Comparative Examples 1 to 6] With respect to the liquid absorbing resin described below, the liquid absorption ratio was measured in the same manner as in Example 1. The results are shown in Table 1 and FIG.

Comparative liquid absorbing resin (1): polyacrylamide crosslinked polymer obtained in Comparative Production Example 1 Comparative liquid absorbing resin (2): acrylamide-Na acrylate crosslinked copolymer obtained in Comparative Production Example 2 Liquid-absorbent resin (3): N-vinylacetamide crosslinked polymer (NA-010; manufactured by Showa Denko KK) Comparative liquid-absorbent resin (4): Polyacrylic acid partially Na salt crosslinked polymer (AQUALIC CA-W4; Comparative Liquid Absorbent Resin (5): Post-crosslinked Polyvinylpyrrolidone Obtained in Comparative Production Example 3 Comparative Liquid Absorbent Resin (6): Polyvinylpyrrolidone Postcrosslinked Product Obtained in Comparative Production Example 4 [Execution Examples 4 to 6] Absorbent resin (1) obtained in Production Examples 1 to 3
(3) was evaluated based on the above-mentioned [Evaluation method 1 for moisture absorption state]. The results are shown in [Table 2]. As is clear from Table 2, since the hygroscopic composition of the present invention completely absorbs the deliquescent liquid due to the deliquescent substance absorbing,
The deliquescence did not flow at all.

Comparative Examples 7 to 13 The comparative liquid-absorbent resins (1) to (6) and the comparative water-soluble resin (1) were evaluated in the same manner as in Examples 4 to 6. [Table 2]
It was shown to. Comparative water-soluble resin (1): polyethylene oxide (Mw
= 200,000) [Examples 7 to 9] Absorbent resin (1) obtained in Production Examples 1 to 3
(3) was evaluated based on the above-mentioned [Evaluation method 2 for moisture absorption state]. The results are shown in [Table 3]. As is evident from Table 3, the hygroscopic composition of the present invention completely absorbs the deliquescent liquid by absorbing the deliquescent substance,
The deliquescence did not flow at all. In addition, as shown in the reference table (Table 4), it became clear that the liquid absorbing speed was also higher than that of the comparative liquid absorbing resin.

Comparative Examples 14 to 20 The comparative liquid-absorbent resins (1) to (6) and the comparative water-soluble resin (1) were evaluated in the same manner as in Examples 7 to 9. The results are shown in [Table 3].

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

[Table 4]

[0049]

According to the present invention, a deliquescence retaining ability is provided by a liquid-absorbing resin capable of highly absorbing the deliquescence while containing a deliquescent substance which has a high hygroscopic capacity but is deliquescent. A hygroscopic composition can be provided. According to the present invention, not only does the deliquescent substance absorb moisture and deliquescent, it has excellent deliquescence retention ability due to the liquid absorbent resin that can highly absorb the deliquescence generated, and the deliquescent substance absorbs and deliquesces. That is, it is possible to provide a hygroscopic agent that allows a user to visually confirm that the dehumidifying ability is lost, and a method for producing the hygroscopic agent.

[Brief description of the drawings]

FIG. 1 is a view showing Evaluation Method 1 of a moisture absorption state.

FIG. 2 is a view showing Evaluation Method 2 of a moisture absorption state.

FIG. 3 shows the concentration (% by weight) of the aqueous solution of calcium chloride on the X-axis and the absorption ratio (g / g) on the Y-axis, and the absorption ratio of each absorbent resin when the concentration of the aqueous calcium chloride solution is changed. FIG. 4 is a diagram in which is a line graph.

FIG. 4 is a view showing a method for producing a moisture absorbent of the present invention, in which a moisture absorbent composition obtained by mixing a solid deliquescent substance and a liquid absorbent resin is packaged with a moisture permeable film.

FIG. 5: Using a perforated plate, a solid deliquescent substance,
It is a figure which shows the manufacturing method of the hygroscopic agent of this invention which arrange | positions a liquid-absorbent resin in the state which contacts with this liquid-absorbent resin when the deliquescent substance liquefies and liquefies.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D052 AA09 CA03 CA06 GA04 GB00 GB17 HA11 HA12 HA14 HA27 4G066 AA36B AB05A AB12A AC33B AC35B BA12 BA20 BA36 BA42 CA43 DA03 FA07 FA21 4J002 BJ001 DD056 DD066 DD086 DE056 DE086 DG046 GC00

Claims (7)

[Claims] 1. A crosslinked polymer obtained by polymerizing a monomer component mainly composed of a cyclic N-vinyllactam,
Absorption capacity of saturated aqueous calcium chloride solution at 20 g
/ G or more, and a liquid absorbent resin and a solid deliquescent substance. 2. The hygroscopic composition according to claim 1, wherein the composition comprises a solid deliquescent substance in an amount calculated from the following formula (1) per 1 part by weight of the liquid absorbing resin. . Calculation formula (1): Amount of deliquescent substance (parts by weight) = deliquescence concentration of deliquescent substance (% by weight) x liquid absorption ratio of liquid absorbent resin (g /
g) 3. The method according to claim 1, wherein the cyclic N-vinyl lactam is N-vinyl-2.
The hygroscopic composition according to claim 1 or 2, which is -pyrrolidone. 4. A hygroscopic agent containing a liquid absorbing resin and a solid deliquescent substance, wherein the liquid absorbing resin is obtained by polymerizing a monomer component mainly composed of cyclic N-vinyl lactam. The crosslinked polymer obtained has a liquid absorption capacity of a saturated calcium chloride aqueous solution at 25 ° C. of 20 g / g or more, is mixed with the solid deliquescent substance, and is packaged in a packaging material. A hygroscopic agent, characterized in that at least a part of the material is a moisture-permeable film. 5. A method for producing a hygroscopic agent containing a liquid-absorbent resin and a solid deliquescent substance, wherein the liquid-absorbent resin comprises a cyclic N
A cross-linked polymer obtained by polymerizing a monomer component containing vinyl lactam as a main component, wherein the liquid absorption capacity of a saturated calcium chloride aqueous solution at 25 ° C. is 20 g / g or more; And packaging with a packaging material, at least a part of which is a moisture-permeable film. 6. A hygroscopic agent containing a liquid absorbing resin and a solid deliquescent substance, wherein the liquid absorbing resin is obtained by polymerizing a monomer component mainly composed of cyclic N-vinyl lactam. The resulting crosslinked polymer has a liquid absorption capacity of a saturated calcium chloride aqueous solution at 25 ° C. of 20 g / g or more, and has a liquid absorption property when the solid deliquescent substance is deliquescent by absorption and becomes liquid. A hygroscopic agent, which is arranged to be in contact with a resin. 7. A method for producing a hygroscopic agent containing a liquid-absorbent resin and a solid deliquescent substance, wherein the liquid-absorbent resin contains a monomer component mainly composed of cyclic N-vinyllactam. A crosslinked polymer obtained by polymerization, wherein the liquid absorption capacity of a saturated calcium chloride aqueous solution at 25 ° C. is 20 g / g or more, and the solid deliquescent substance absorbs moisture and deliquesces to form a liquid. A method for producing a hygroscopic agent, wherein the method is arranged so as to be in contact with a liquid absorbing resin.