JPH05103944A - Hygroscopic material - Google Patents

Abstract

PURPOSE:To provide a hygroscopic material causing no sag-even at the time of moisture absorption and exhibiting high hygroscopic property. CONSTITUTION:A compsn. contg. a water-soluble unsatd. monomer and a crosslinking agent is polymerized in the presence of a deliquescent inorg. salt and the resulting hygroscopic resin is incorporated into a base material to obtain a hygroscopic material.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel hygroscopic material. More specifically, it relates to a hygroscopic material having excellent hygroscopic properties and excellent workability and workability.

[0002]

2. Description of the Related Art Conventionally, inorganic compounds such as calcium chloride and silica gel have been used as hygroscopic substances. Among them, calcium chloride is widely used because it is inexpensive and has a large hygroscopic ability. However, since calcium chloride is granular, it is difficult to handle, and since it liquefies due to moisture absorption, it has drawbacks such as spilling and staining other things.

In order to make up for this drawback, a hygroscopic agent prepared by mixing a water-soluble resin and calcium chloride (Japanese Patent Publication No. 60-28531).
No.) and a hygroscopic material in which a powdery water-absorbent resin is fixed to a fibrous base material (Japanese Patent Publication No. 3-13359) are also proposed. There was a problem that it was missing.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above problems. Therefore, an object of the present invention is to provide a novel hygroscopic material which is free from liquid dripping, has excellent hygroscopic properties and is easy to handle.

[0005]

[Means and Actions for Solving Problems] As a result of intensive studies to solve the above problems, the present inventors have found that hygroscopic resins produced under limited conditions are In terms of speed, amount of moisture absorption, liquid dripping after moisture absorption, etc., it has much more excellent properties than previously known combinations, and by incorporating this in various base materials, it is extremely hygroscopic. The inventors have found that the following can be obtained and reached the present invention.

That is, according to the present invention, a hygroscopic resin containing a water-soluble unsaturated monomer and a cross-linking agent in a base material contains a hygroscopic resin obtained by polymerization in the presence of a deliquescent inorganic salt. The material is provided.

The hygroscopic resin according to the present invention is produced, for example, by polymerizing a water-soluble unsaturated monomer in the presence of a crosslinking agent and a deliquescent inorganic salt by using a known polymerization method such as heat, radiation and light. it can.

Water-soluble unsaturated monomers that can be used include
Monomers having a carboxyl group such as (meth) acrylic acid and maleic anhydride; (meth) acrylic acid sodium salt,
Monomers having carboxyl groups in the form of salts such as potassium (meth) acrylic acid salts, ammonium (meth) acrylic acid salts and sodium maleic acid salts; vinyl sulfonic acid, styrene sulfonic acid, sulfopropyl (meth) acrylic acid, etc. Monomers having sulfonic acid groups; vinyl sulfonic acid sodium salt, vinyl sulfonic acid methylamine salt, (meth)
Monomers having sulfonates such as sulfopropyl sodium acrylate; Hydroxyl (meth) acrylate, hydroxypropyl (meth) acrylate, etc.
Monomers having an ether group such as rumonomethyl ether and trioxyethylene glycol (meth) acrylate;
Monomers having amino groups such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; N, N′-dimethylacrylamide, (meth) acrylamide, N-vinylpyrrolidone, N-methylolated Monomers having amide groups such as acrylamide; N,
Examples thereof include monomers having a quaternary ammonium salt group such as N ′, N ″ -trimethyl-N- (meth) acryloyloxyethylammonium chloride. Preferably, (meth) acrylic acid, maleic anhydride and the like are used. Monomers having a carboxyl group; monomers having a carboxyl group in the form of a salt such as (meth) acrylic acid sodium salt, (meth) acrylic acid potassium salt, (meth) acrylic acid ammonium salt, and maleic acid sodium salt; It is a monomer having an amide group such as N, N′-dimethylacrylamide, (meth) acrylamide, N-vinylpyrrolidone, N-methylolacrylamide.

Examples of the cross-linking agent include di- or tri- (meth) acrylic acid esters of polyols such as ethylene glycol, trimethylolpropane, glycerin, polyoxyethylene glycol and polyoxypropylene glycol. Unsaturated polyesters obtained by reacting the above-mentioned polyols with unsaturated acids such as maleic acid; N, N '
-Bisacrylamides such as methylene-bisacrylamide; allyl compounds such as tetraallyloxyethane, triallylamine, and allylated cellulose; di- or tri- () obtained by reacting a polyepoxide with (meth) acrylic acid. Examples of the (meth) acrylic acid ester include difunctional compounds such as methylated (meth) acrylamide, glyoxal, ethylene glycol, ethylene glycol diglycidyl ether and hydroxylation. Calcium etc. can also be used. A cross-linking agent having at least two polymerizable double bonds copolymerizable with the water-soluble unsaturated monomer is preferable.

The deliquescent inorganic salt refers to an inorganic salt in which the water vapor pressure of its saturated aqueous solution is smaller than the water vapor partial pressure of the atmosphere,
Specific examples thereof include halides such as chlorides, bromides and iodides of calcium, magnesium, lithium, zinc, aluminum and tin. Among them, magnesium chloride and lithium chloride can be preferably used from the viewpoint of hygroscopic ability.

The composition of the water-soluble unsaturated monomer, the cross-linking agent, and the deliquescent inorganic salt is not particularly limited, but from the viewpoint of hygroscopic properties, the water-soluble unsaturated monomer, the cross-linking agent, and the deliquescent inorganic salt. The weight ratio of the crosslinking agent is 0.0001 to 10 and the deliquescent inorganic salt is 10 to 1000 with respect to 100 of the water-soluble unsaturated monomer.
Is preferred.

As the polymerization solvent, for example, water, methanol,
Ethanol, acetone, DMF and mixtures thereof can be used, preferably water.

When, for example, water is used as the polymerization solvent, the hygroscopic resin of the present invention is optionally subjected to a drying step and a pulverizing step. A hygroscopic resin can be used without going through a crushing or drying step. Further, if necessary, classification can be carried out to adjust to a desired particle size. The shape of the hygroscopic resin is not particularly limited, and may be any shape such as powdery, flaky, pallet-like, fibrous or sheet-like.

The hygroscopic resin obtained by polymerization is contained in various base materials by a method such as spraying or mixing to form the hygroscopic material of the present invention. As the base material, natural fibers such as pulp, rayon and cotton; synthetic fibers such as polyolefin and polyester; webs formed from natural fibers and synthetic fibers,
Nonwoven fabrics, woven fabrics and papers; porous substrates such as sponge-like substrates such as rubber sponge and urethane foam, and thermoplastic resin sheets
Various materials such as gypsum, plaster, sawdust, sand, and soil can be used. A sheet-like porous fibrous base material is preferably used as a material that can maximize the hygroscopic capacity of the hygroscopic resin. Since it is molded into a sheet, it can be handled and stored easily, and can be used in a wide range.
In some cases, the polymerization is carried out in the presence of a fibrous base material.
It is also possible to obtain the moisture absorbent of the present invention in stages. The moisture absorbent of the present invention can also be used by putting it in a moisture permeable bag or box.

Further, a deodorant; an antiseptic / antifungal agent; an aromatic agent; a coloring agent and the like can be added to the moisture absorbent of the present invention.

The hygroscopic material of the present invention not only has an excellent hygroscopic capacity, but also has no fear of being liquefied even after absorbing moisture, and thus can be used for various purposes. For example, a) Dehumidifying material for living room, closet, getter box, shoes, rocker, etc. B) Drying materials for products such as seaweed and rice crackers, which are sold in a closed container that dislikes moisture absorption. C) Dew condensation prevention material. D) Packaging materials for equipment that does not like rusting. E) Humidity control material. Can be used effectively.
Further, the hygroscopic material of the present invention has a feature that it can be repeatedly used without losing the initial hygroscopic ability by drying even after hygroscopicity.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. Parts and% in the examples and comparative examples are by weight.

[0018]

[Reference Example 1] 37% sodium acrylate aqueous solution 360
Parts, acrylic acid 34 parts, methylenebisacrylamide 0.03 parts, and 37% magnesium chloride aqueous solution 450 parts were placed in an openable and closable closed container, and the liquid temperature was adjusted to 3 under a nitrogen atmosphere.
After the temperature was set to 5 ° C, 30 parts of a 3% ammonium persulfate aqueous solution and 25 parts of a 0.3% l-ascorbic acid aqueous solution were added to initiate polymerization. After aging for 1 hour at 80 ° C,
The gel polymer was taken out, dried in a hot air dryer at 150 ° C., and pulverized to a particle size of 10 to 50 mesh to obtain a hygroscopic resin (1).

[0019]

[Reference Example 2] 130 parts of sodium 2-acryloylethanesulfonate aqueous solution, 280% 37% lithium chloride aqueous solution
Parts, and 0.2 parts of methylenebisacrylamide were charged into a polymerization vessel, and the temperature of the solution was adjusted to 25 ° C. under a nitrogen atmosphere, and then 10 parts of 1% hydrogen peroxide aqueous solution and 0.04% 1-ascorbic acid aqueous solution 10 parts and % 2,2'-azobis (2-amidinopropane) dihydrochloride aqueous solution was added to initiate polymerization. After aging at 90 ° C. for 2 hours, the gel polymer was taken out, dried in a hot air dryer at 120 ° C., and pulverized to a particle size of 20 to 100 mesh to obtain a hygroscopic resin (2).

[0020]

Example 1 100 parts of hygroscopic resin (1), 100 parts of crushed pulp, and 20 parts of synthetic pulp were dry-mixed, then suction-laminated and heat-treated at 150 ° C. to obtain the moisture-absorbing material of the present invention ( 1) was obtained.

[0021]

Example 2 100 parts of hygroscopic resin (2) and 100
Parts of the crushed pulp were dry-mixed and then suction-laminated to obtain the moisture absorbent (2) of the present invention.

[0022]

COMPARATIVE EXAMPLE 1 100 parts of crushed pulp and 20 parts of synthetic pulp were dry-mixed, suction-laminated, and heat-treated at 150 ° C. to obtain a comparative moisture absorbent (1).

[0023]

Comparative Example 2 100 parts of magnesium chloride, 100 parts of crushed pulp, and 20 parts of synthetic pulp were dry-mixed, then suction-laminated and heat-treated at 150 ° C. to obtain a comparative hygroscopic material (2).

[0024]

Comparative Example 3 100 parts of a commercially available water-absorbent resin (trade name: Sunwet IM1000, manufactured by Sanyo Kasei Co., Ltd.), 100 parts of crushed pulp, and 10 parts of synthetic pulp were dry-mixed and then suction-laminated, Comparative moisture absorbent (3) was obtained by heat treatment at 150 ° C.

[0025]

[Embodiment 4] The hygroscopic materials (1) and (2) of the present invention obtained in Embodiment 1 and Embodiment 2 are each added in an amount of 1.0 g each.
Put in a 00ml glass container, 25 ℃, relative humidity 90%
The sample was left in a constant temperature and constant humidity tank, and the amount of weight increase was measured with time to examine the amount of moisture absorption. The results and the surface condition after 10 hours are shown in Table 1. For comparison, Table 1 also shows the results when the same amount of the comparative hygroscopic materials of Comparative Examples 1, 2, and 3 was used, and the results when only magnesium chloride was used as a blank. All samples were used after being sufficiently dried.
As is clear from Table 1, the moisture-absorbing material of the present invention has an excellent moisture-absorption rate and moisture-absorption amount, and since there is no liquid dripping after moisture absorption, no surface dew condensation occurs.

[0026]

Example 5 The sample after moisture absorption obtained in Example 4 was dried again, and the operation of Example 4 was repeated to compare repeated moisture absorption effects. Table 2 shows the results of the fourth repetition. It can be seen that the hygroscopic material of the present invention can be repeatedly used, and the effect at that time is not reduced.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

The hygroscopic material of the present invention has not only excellent hygroscopic properties but also no liquid dripping even after hygroscopicity, and is also easy to handle.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadao Shimomura 5-8 Nishimitabicho, Suita City, Osaka Pref.

Claims (2)

[Claims] 1. A hygroscopic material containing a hygroscopic resin obtained by polymerizing a component containing a water-soluble unsaturated monomer and a cross-linking agent in the presence of a deliquescent inorganic salt in a substrate. 2. The hygroscopic material according to claim 1, which is a sheet-like material.