JPH0859743A - Liquid absorbent - Google Patents

Abstract

PURPOSE: To obtain a cross-linked polymer useful as an absorbent, a water retaining agent, etc., having excellent chemical stability, liquid absorbing properties for an aqueous liquid or an alcohol, gel strength and economic efficiency by copolymerizing a specific N-vinylcarboxylic acid amide with an allyl compound or a vinyl ester compound. CONSTITUTION: This cross-linked polymer is obtained by copolymerizing (A) an N--vinylcarboxylic acid amide of formula I (R<1> and R<2> are H or CH3 ) or a mixture of it and a monomer copolymerizable with it, (B) a compound containing two or more allyl groups in one molecule [e.g. a compound of the formula, (CH2 =CH-CH2 -)n )-Z ((n) is >=2; Z is an nvalent organic group)] or (C) a compound containing two or more vinyl ester structures in one molecule [e.g. a compound of formula II ((m)>=2; Z' is an m-valent organic group)] and absorbs >=10 times as much water as the empty weight.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel crosslinked polymer having excellent gel strength and chemical stability, hardly affected by an electrolyte, and swelling in an aqueous liquid, alcohol and other organic solvents. Regarding how to use it.

[0002]

2. Description of the Prior Art Crosslinked polymers are insoluble in their solvents,
Since it often has special properties different from the non-crosslinked polymer in terms of strength as a material and other points, it is industrially used for various purposes such as a photosensitive resin and a reinforcing material. In particular, in recent years, water-swellable polymers having a structure in which a water-soluble polymer is cross-linked have attracted attention in applications in various industrial fields utilizing their water absorption and water retention properties. For example, hygiene materials such as disposable diapers, sanitary products, contact lenses, cosmetics, paints, adhesives, water-stopping agents, soil modifiers, etc., and applications and research in the medical field such as controlled drug release are active. Is. In addition, research and development are also underway in fields of application that utilize the stimulus responsiveness of swellable crosslinked polymers to pH, heat, light, solvents and the like. These crosslinked polymers have been produced by various methods,
As a method often used industrially, when a polymer is obtained by addition-polymerizing one or more kinds of vinyl compounds as monomers by a method such as radical polymerization, a vinyl group copolymerizable with the vinyl compound, etc. A typical method is to introduce a crosslinking point into the polymer chain by copolymerizing with a compound having a plurality of functional groups (i.e., a crosslinking agent).

As the cross-linking agent used when the water-swellable cross-linked polymer is produced by the above method, a compound having a plurality of vinyl groups copolymerizable with the monomer is generally used. Examples of such cross-linking agents currently known include N, N'-methylenebisacrylamide, ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and other acrylamide structures and There are compounds having a (meth) acrylic acid structure.

However, as described above, compounds having various structures are known as compounds capable of functioning as a cross-linking agent, but depending on the use of the cross-linked polymer and the kind of the monomer, the performance, the structure and the like are not always required. In many cases, there was no crosslinking agent that met all the requirements. For example, copolymerizability of a vinyl compound which is a monomer and a crosslinking agent,
This is the case where a crosslinking agent having sufficient performance to satisfy the conditions such as the solubility of the crosslinking agent in a solvent and the stability upon modification after crosslinking is not known. Thus, when an attempt is made to synthesize a crosslinked polymer using a crosslinking agent that does not sufficiently meet the desired requirements, the crosslinking agent does not proceed uniformly and the crosslinking agent is not effectively used. The strength of the cross-linked polymer is insufficient, a large amount of solvent-soluble polymer is produced because it is not sufficiently cross-linked, and the amount of the cross-linking agent required to obtain a satisfactory cross-linked polymer is very large. There is a problem such as doing. In particular, the copolymerizability of the vinyl group and the monomer in the cross-linking agent is an important factor, and if the so-called reactivity ratios of the respective vinyl groups are greatly different, the desired cross-linking weight is increased due to the problems mentioned above. You can't get coalesced. In the present invention, the expression “copolymerizability of the monomer and the cross-linking agent is good” means the reactivity ratio defined in the Mayo-Lewis formula between the vinyl group of the cross-linking agent and the vinyl group of the monomer. It means a system in which r ₁ and r ₂ are close to each other, and the cross-linking points are relatively uniformly introduced into the polymer molecular chain from the beginning to the end of the polymerization reaction.

By the way, in the production of N-vinylcarboxylic acid amide type liquid swellable crosslinked polymer, when the liquid swellable crosslinked polymer is produced by using the above-mentioned crosslinking agents as the crosslinking agent, conventional water As compared with the swellable cross-linked polymer, a polymer having an excellent ability to absorb an aqueous solution containing an electrolyte is obtained. That is, most of the conventional water-swellable cross-linked polymers are polycarboxylic acids (salts), and therefore their liquid absorption capacity largely depends on the concentration of electrolytes in an aqueous solution, especially the concentration of polyvalent metal ions such as calcium ions. The N-vinylcarboxylic acid amide-based liquid swellable crosslinked polymer is hardly affected by the electrolyte concentration in the aqueous solution, and has the ability to absorb an organic solvent such as alcohol. However, since the copolymerizability of the N-vinylcarboxylic acid amide and the above-mentioned crosslinking agent is not always good, the polymer chain is not sufficiently crosslinked, and a large amount of a polymer soluble in a solvent is generated, or sufficient crosslinking is performed. There has been a problem that the amount of the cross-linking agent required to obtain a cross-linked polymer having a density becomes very large. In addition, JP-A-4-323213
In the publication, a method for producing a fine N-vinylamide resin having an average particle diameter of 10 μm or less using a polyallyl compound as a crosslinking agent is described as an example.
The vinylamide resin is a polymer having a high cross-linking density that exhibits a thixotropic thickening property, does not have the property of a liquid-swelling cross-linking polymer that absorbs and retains a liquid, for example, in a state of absorbing a liquid. The fine particle cross-linked polymer cannot be filtered because it blocks the sieve.

Further, Japanese Patent Laid-Open No. 4-230250 discloses a screw (N
-Vinylcarboxylic acid amide) -based novel compounds are disclosed to be used as a crosslinking agent in the production of N-vinylcarboxylic acid amide-based liquid swellable crosslinked polymers. Since this bis (N-vinylcarboxylic acid amide) -based compound exhibits good copolymerizability with N-vinylcarboxylic acid amide, the N-vinylcarboxylic acid amide-based liquid swellable crosslinkable product obtained by copolymerizing the crosslinking agent is used. The polymer has the advantages that the polymer chains are sufficiently cross-linked, the amount of the polymer soluble in the solvent is small, and that the polymer has extremely excellent liquid absorbency and gel strength. However, since this bis (N-vinylcarboxylic acid amide) -based compound is not commercially available, it has to be produced by itself, and since this compound is produced through complicated steps, it is very expensive. There was a drawback. Furthermore,
The cross-linked polymer produced using the compound had a problem that a small amount of a polymer soluble in a solvent was present.

[0007]

Accordingly, the inventors of the present invention have a good copolymerizability with N-vinylcarboxylic acid amide more than a bis (N-vinylcarboxylic acid amide) type compound and are easily available. The present invention has been achieved as a result of extensive studies on an N-vinylcarboxylic acid amide-based liquid swellable crosslinked polymer using a crosslinking agent that can be produced at low cost.

[0008]

The present invention provides (1) N-vinylcarboxylic acid amide represented by the following general formula [A] alone or a mixture with a monomer copolymerizable with the N-vinylcarboxylic acid amide. And a cross-linked polymer that absorbs water at least 10 times its own weight, obtained by copolymerizing a compound having two or more allyl groups in one molecule or a compound having two or more vinyl ester structures in one molecule,

[Chemical 3] [In the formula, R ¹ and R ² independently represent hydrogen or a methyl group. (2) N-vinylcarboxylic acid amide represented by the general formula [A] alone or a mixture of a monomer copolymerizable with the N-vinylcarboxylic acid amide, and one molecule represented by the general formula [B] A compound having two or more allyl groups in 1 or 1
The molar ratio of the compound having two or more vinyl ester structures in the molecule is 90:10 to 99.9999: 0.0.
001 (1) concerning the crosslinked polymer of statement (here,
The [B] represented by the following general formula [I] or _{[II]), (CH 2 = CH-} CH 2 -) n -Z (I)

[Chemical 4] [In the formula, n and m are integers of 2 or more, and Z and Z'represent an n-valent and m-valent organic group, respectively. (3) The molar ratio of the N-vinylcarboxylic acid amide represented by the general formula [A] to the monomer copolymerizable with the N-vinylcarboxylic acid amide is 50:50 to 100: 0.
The crosslinked polymer according to (1) to (2), wherein (4)
A liquid absorbent for an aqueous liquid or / and an organic solvent, which comprises using the crosslinked polymer according to any one of (1) to (3), wherein (5) the organic solvent is a solvent polarity parameter E.
The liquid absorbent according to (4), which is a single liquid having a _T value of 45 or more or a mixed liquid having an E _T value of 43 or more, (6) (1) to
(3) A water retentive agent for vegetation or artificial medium, characterized by using the crosslinked polymer as described in (3),
A body fluid absorbent for hygiene products, characterized by using the crosslinked polymer according to any one of (1) to (3).
(3) A cross-linking polymer described in (3) is used, which relates to an auxiliary agent for a hygroscopic agent using calcium chloride, (9) (1)
The present invention relates to a liquid absorbent and a liquid absorbent article obtained by mixing the crosslinked polymer described in (3) and a powdery organic polymer substance.

The present invention will be described in more detail below. Examples of the N-vinylcarboxylic acid amide that can be used in the present invention include N-vinylacetamide, N-methyl-N-vinylacetamide, N-vinylformamide,
N-methyl-N-vinylformamide may be mentioned, of which N-vinylacetamide is preferred. Examples of vinyl compounds copolymerizable with these N-vinylcarboxylic acid amides include acrylic acid, sodium acrylate,
Potassium acrylate, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, sodium salt or potassium salt thereof, dimethylaminoethyl (meth) acrylate and quaternary salt thereof, dimethylaminopropyl (meth) acrylamide and quaternary salt thereof, Methacrylic acid, sodium methacrylate, 2-hydroxyethyl methacrylate and the like can be mentioned. Further, the molar ratio of N-vinylcarboxylic acid amide and the monomer copolymerizable with the N-vinylcarboxylic acid amide is 100: 0 to 50:50.
Is preferred, and more preferably 10 by weight.
It is 0: 0 to 50:50. If the ratio of the copolymerizable monomer is higher than this, the liquid absorbing performance of the electrolyte-containing aqueous solution of the crosslinked polymer is deteriorated, which is not preferable.

The cross-linking agent used in the present invention is a compound which shows very good copolymerizability with N-vinyl carboxylic acid amide. The present inventors have found that among cross-linking agents that are easily available or easily manufactured, a cross-linking agent having a specific structure shows very good copolymerizability with N-vinylcarboxylic acid amide, and The obtained crosslinked polymer has the same level of performance in terms of liquid absorption performance and gel strength as the crosslinked polymer produced using bis (N-vinylcarboxylic acid amide) as a crosslinking agent, and It was found that the amount of solvent-soluble polymer in the crosslinked polymer was small. here,
The cross-linking agent having a specific structure is a compound having two or more allyl groups in one molecule or a compound having two or more vinyl ester structures in one molecule. Considering the availability and the small amount of water-soluble polymer,
The former compound is advantageous.

The compound having two or more allyl groups in one molecule can be represented by the above general formula [I]. Although n represents an integer of 2 or more, an integer of 6 or less is suitable, and 3, 4 and 5 are particularly preferable. Z represents an n-valent organic group,
During the production of the crosslinked polymer of the present invention, it may be substituted with an atomic group or atom which is inert to the crosslinking reaction by addition polymerization. For example, acetals such as tetraallyloxyethane, pentaerythritol tetraallyl ether,
Pentaerythritol triallyl ether, pentaerythritol diallyl ether, trimethylolpropane triallyl ether, trimethylolpropane diallyl ether, ethylene glycol diallyl ether, diethylene glycol diallyl ether, triethylene glycol diallyl ether, diallyl ether, monosaccharides,
Ethers such as polyallyl ethers derived from compounds having two or more hydroxyl groups in one molecule such as disaccharides, polysaccharides and cellulose, tetraallyl pyromellitic acid, triallyl trimellitic acid, triallyl citrate, diallyl oxalate, amber Acid diallyl, diallyl adipate, diallyl maleate, diallyl fumarate, diallyl terephthalate, diallyl isophthalate, diallyl phthalate, 1
Esters such as polyallyl esters derived from compounds having two or more carboxyl groups in the molecule, and others,
Examples thereof include diallylamine, triallyl isocyanurate, triallyl cyanurate and the like.

Further, two vinyl ester structures are included in one molecule.
The compound having two or more can be represented by the above general formula [II]. m represents an integer of 2 or more, but an integer of 5 or less is suitable, and 2,3,4 is particularly preferable. Z'represents an m-valent organic group, and in the production of the crosslinked polymer of the present invention,
It may be substituted with an atomic group or atom that is inactive to the crosslinking reaction by addition polymerization. For example, divinyl oxalate, divinyl malonate, divinyl succinate, divinyl glutarate, divinyl adipate, divinyl pimelic acid,
Examples thereof include compounds having two or more vinyl ester structures such as divinyl maleate, divinyl fumarate, trivinyl citrate, trivinyl trimellitate and tetravinyl pyromellitic acid. These cross-linking agents may be used alone or in combination of two or more. Further, N, N'-methylenebisacrylamide, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and Compounds having a plurality of acrylamide structures or (meth) acryl groups, such as triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate In addition, a known crosslinking agent such as a compound having two or more unsaturated groups in one molecule such as divinylbenzene, divinyl ether, and allyl (meth) acrylate can be used in combination.

The amount of the cross-linking agent used is such that the molar ratio of monomer: cross-linking agent is 90:10 to 9 based on all the monomers.
The range of 9.9999: 0.0001 is suitable, and is appropriately selected from this range depending on the use of the crosslinked polymer, but usually the range of 95: 5 to 99.99995: 0.0005 is preferable. If the amount of the cross-linking agent used is more than this range, the cross-linking density becomes too high and the phase tends to become non-uniform during the polymerization. Is lost. Further, if the amount of the crosslinking agent used is too small, the strength of the obtained crosslinked polymer is lowered, and further, a part of the crosslinked polymer is dissolved in a solvent, and the performance expected as a water-swellable crosslinked polymer is exhibited. It will not be possible.
The polymerization process is not necessarily limited, but it is usually preferable to use an aqueous solution polymerization method, an inverse suspension polymerization method, an inverse emulsion polymerization method, or the like. For example, as an aqueous solution polymerization method, a monomer component and a cross-linking agent are uniformly dissolved in water or a mixed solvent of a hydrophilic organic solvent such as methanol, tetrahydrofuran, or acetone that can be uniformly mixed with water, and vacuum degassing or After removing the dissolved oxygen in the system by substitution with an inert gas such as nitrogen or carbon dioxide, a polymerization initiator is added to carry out copolymerization. Polymerization initiation temperature is usually -10 to 60 ° C
The polymerization time is about 0.5 to 20 hours.

As the polymerization initiator, a peroxide, an organic or inorganic peracid or a salt thereof, which can be uniformly dissolved in a polymerization solvent, and a redox type one prepared by combining an azobis compound with a reducing agent are used. As typical examples thereof, t-butyl peroxide, benzoyl peroxide, t-butyl hydroperoxide, benzoyl peroxide, azobisisobutyronitrile, 2,2′-azobis (2-amidinopropane) )
Dihydrochloride, 2,2'-azobis [2- (5-methyl-2
-Imidazolin-2-yl) propane] dihydrochloride, sodium persulfate, ammonium persulfate, hydrogen peroxide, and combinations of persulfates with tertiary amines such as triethylamine and triethanolamine. The amount of the polymerization initiator used is in the range of 0.0001 to 5% by weight, preferably 0.001 to 1% by weight, based on all the monomers.
When the amount of the polymerization initiator used is more than 5% by weight, the molecular weight of the main chain of the crosslinked polymer does not increase and a polymer soluble in a solvent may be produced, which is not preferable. Also, 0.00
If the amount is less than 01% by weight, there is a problem that the reaction rate of the polymerization reaction does not increase and the amount of residual monomer increases.

The reaction product is a gel containing the solvent used in the reaction and is usually cut with a rotary cutter or the like.
The solvent is removed by a method such as heating or decompression, followed by drying, and then, if necessary, pulverizing and classifying to obtain a powder having a particle size of several μm to 3 mm. As the reverse phase suspension polymerization method and the reverse phase emulsion polymerization method, a monomer component and a crosslinking agent are uniformly dissolved in water and suspended or emulsified in an organic solvent which is not uniformly mixed with water to carry out a polymerization reaction. As the polymerization initiator, not only water-soluble ones but also those soluble in an organic solvent are used. Therefore, in addition to the above, for example, hydrocarbons such as hexane, cyclohexane, heptane, octane, benzene, toluene, xylene, and ethylbenzene, halogenated hydrocarbons such as carbon tetrachloride, dichloroethane, and mineral oils such as isoper are also used. . Further, in the inverse suspension polymerization method and the inverse emulsion polymerization method, a surfactant is used as a dispersant,
A protective colloid is used together if necessary. Typical examples thereof include sorbitan monostearate, sorbitan monopalmitate, polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose and the like.

The method of removing dissolved oxygen in the system and the amount of the polymerization initiator used are the same as described above. Further, in the case of the reverse phase suspension polymerization method, the polymer is usually obtained in the form of particles of 100 μm to several mm. Therefore, the polymer may be filtered, dried and, if necessary, pulverized after the polymerization. It is also possible to remove water from the polymer by utilizing azeotropic distillation of hydrocarbon and water after the polymerization. In the case of reverse phase emulsion polymerization, the particle size of the polymer is usually about several μm, and the polymer is obtained as an emulsion with a hydrocarbon. This emulsion can be used as it is, or can be used after precipitating a polymer with an inorganic salt or acetone, filtering and drying. The polymerization reaction conditions are not particularly limited, but are generally as follows. The amount of the solvent used is the same as the aqueous monomer solution to 20 times, preferably the same amount to 10 times, particularly preferably the same amount to 5 times, the polymerization initiation temperature is about −10 ° C. to 90 ° C., and the reaction time is 0.5 to 20. It's about time.

The raw materials and process for producing the crosslinked polymer of the present invention are as described above, but it is essential that the crosslinked polymer of the present invention absorbs water 10 times or more its own weight. This enables the use as a liquid absorbent as described below. The N-vinylcarboxylic acid amide crosslinked polymer (liquid absorbent) of the present invention is primarily obtained in the form of powder having a particle size of several μm to several mm as described above. Dispersions, creams, paste-like viscous substances, etc., and can be molded into string-like, film-like, sheet-like, plate-like and various molded products, and can be combined with various base materials into various shapes and forms. Used.
The liquid absorbent mainly composed of the N-vinylcarboxylic acid amide crosslinked polymer of the present invention is an N-vinylcarboxylic acid amide crosslinked polymer using a bis (N-vinylcarboxylic acid amide) compound as a crosslinking agent. Similar to the liquid absorbent as the main component, it basically has an excellent absorption function for aqueous liquids and organic solvents with ionic resistance, chemical stability, and light resistance, but it absorbs and releases liquids. And the control function and sustained release, decrease in fluidity with respect to the added system, solidification, shapeability or adhesion to the external environment, sealing property or a kind of adhesiveness, coating property, and the above-mentioned for molded products having elasticity. In addition to its water retention and liquid absorption properties, it also absorbs vibrations and shocks and exerts sound absorption properties.

In the liquid absorbent of the present invention, a metal salt or an amine is particularly contained in the liquid to be absorbed by the sodium acrylate crosslinked polymer, which has hitherto been represented by water-swellable crosslinked polymers.
It has the drawback that its liquid absorption performance is significantly impaired when inorganic or organic ions such as carboxylic acid coexist, whereas it is less susceptible to the coexistence of ions, and therefore, even in an aqueous solution containing salts Is hardly reduced. In addition, the water absorbed and retained in the resin can be easily reused by plants and the like, and does not adversely affect the germination, rooting and growth of plants. As applications utilizing such characteristics, for example, in general farmland, mountain forests, etc., especially in relatively salty soil such as desert greening or medium containing artificial salt or fertilizer such as tissue culture or artificial cultivation, artificial soil. Water-retaining agent, absorbent for body fluids with high salt content (urine, menstrual blood) such as hygiene products (diapers, napkins, tampons), concrete curing,
Absorbent of water with high calcium content such as cement modifier, non-fluidizing agent of deliquescent liquid of calcium chloride type hygroscopic agent, dispersant of metal salt solution for producing ultrafine ceramics (complex forming agent with metal compound) ), A protein concentrate from an aqueous solution, an absorbent as a mixture with an organic polymer, and an absorbent article.

In the liquid absorbent of the present invention, particularly, the liquid to be absorbed of the sodium acrylate crosslinked polymer, which has hitherto been represented by the water-swellable crosslinked polymer, is water or water and a part of lower alcohol. However, it is also possible to absorb aqueous liquids, various organic solvents or mixtures thereof. Typical examples of the absorbable organic solvent include the followings, for example, and these are generally called relatively polar solvents. Methanol, ethanol, 1-propanol, 1-butanol, 2-butanol, isobutyl alcohol, isoamyl alcohol, cyclopentanol, allyl alcohol, 1,1,1,3,3,3-
Hexafluoro-2-propanol, 2-methoxyethanol, 2-butoxyethanol, 2-aminoethanol, ethylene glycol, trimethylene glycol, propylene glycol, 1,4-butanediol, 1,3
-Alcohols such as butanediol, 2,3-butanediol, triethylene glycol and glycerin, phenols such as phenol and cresol, and others, formamide, acetic acid, 2-pyrrolidinone, dimethyl sulfoxide, pyridine and the like, and further alone However, if it is not absorbable or is very poor, but it can be absorbed if it is a mixed system, for example, water and dimethylformamide, phenol,
A water-organic solvent mixed system such as acetone, tetrahydrofuran, dioxane, a mixed solvent system of organic solvents such as ethanol-acetone, ethanol-chloroform, ethanol-benzene, ethanol-ethyl acetate, methanol-methylene chloride, ethyl acetate-acetic acid. Shown.

Although the reason why the liquid absorbent of the present invention absorbs such a wide range of solvents is not always clear, it can be absorbed with the N-vinylcarboxylic acid amide crosslinked polymer which is the main component of the liquid absorbent of the present invention. As a measure of the strength of interaction with various solvent systems, the high polarity of the solvent system is considered. In general, as a measure of the polarity of the solvent, results dielectric constant (epsilon), solubility parameter ([delta]), but such a solvent polarity parameter (E _T value or Z value) are known, made various analyzed by these parameters , The above-mentioned organic solvents each have an E _T value of 45 or more in a single solvent, and the E _T value of the solvent system in a mixed solvent is 43 or more, and conversely, those having an E _T value of less than this value are hardly absorbed. Was confirmed. Accordingly, as the liquid absorbent capable of absorbing organic solvents of the present invention, E _T value of 45 or more in a single solvent, the mixed solvent E _T value of the solvent system is capable of 43 or more. In particular, the relationship between the E _T value and the absorbability is well applied to both the single solvent and the mixed solvent, the E _T value is 50 or more,
More preferably, it is 53 or more. If typical applications other than the above are specifically listed, for example, the following can be mentioned. Of course, these are merely examples, and the application of the liquid absorbent of the present invention is not limited to the following, and it is possible to utilize the above-mentioned function in various fields and products in a very wide range. Is.

Since the crosslinked polymer according to the present invention has the ability to absorb an aqueous solution containing various salts and a certain organic solvent, it has liquid absorption, thickening effect, dew condensation prevention, water retention, retention / sustained release of a medicinal agent. It can be used in various applications utilizing functions such as a stimulus response gel, and specific examples thereof are as follows. Food products (freshness preservation products, dehydration, water retention, water supply, water regulators) Agricultural and horticultural products (soil conditioners, seedlings and culture base materials, water retention agents for seedlings (forestation, desert greening, etc.), seed preparations , Frost damage and dew condensation prevention agents (agents) Household, architectural moisture absorption, dew condensation prevention, drip-proofing agents Communication cables, equipment waterproofing, water blocking materials (agents) dehydration,
Water retention, water regulator Various sustained release preparations for oral and enteral medicines, health foods, feed additives, agricultural chemicals, fertilizers, etc. Medical supplies (patches, mucosal preparations, suppositories) Auxiliaries for preparations (binders, binders, Covering agents) Toiletry hygiene products (paper diapers, sanitary napkins, other excrement disposal agents) Civil engineering, construction, household, various industrial sealing materials, putty,
Paint aid, adhesive tape, salt damage and dust prevention agent (material)
Adhesiveness, covering properties, etc. of base materials and assistants Water blocking agents for civil engineering, sandbags filled with liquid absorbents, pore shields and mines,
Excavation aids for foundations such as tunnels, buildings and piers, lubricants Household fragrances, deodorants, fire extinguishing agents, heat storage agents (cooling, heat retaining) Batteries, electrodes, sensor members Antistatic materials, etc. Anti-heat (convection) prevention, vibration absorption, sound-absorbing material, packing Cosmetics (scrub face wash, pack agent, fragrance) Decrease in fluidity of contact lens cleaners, solidification, or from diluent diluted aqueous solution Protein concentration

A specific method of using the liquid absorbent of the present invention,
The amount used cannot be generally stated because it varies slightly depending on the intended use, but in principle, it does not differ significantly from the general and standard modes of use for each intended use. However, due to its excellent functions and effects, we can expect use cases that have never existed before,
Needless to say, it is possible to reduce the amount used to achieve the same effect.

[0023]

The present invention will be described in more detail with reference to the following examples, but it goes without saying that the technical scope of the present invention is not limited to these examples.

Example 1 In a bath kept at 30 ° C., 250 g of N-vinylacetamide and tetraallyloxyethane (Tokyo Kasei Co., Ltd.) were placed in a three-necked 1 L separable flask equipped with a nitrogen inlet tube, a thermometer, and an exhaust tube. 600 mg (manufactured by Co., Ltd.) was dissolved in 745 g of deionized water, and nitrogen was introduced into the system at 0.5 L / min for about 1 hour to degas. Then, 75 mg of 2,2'-azobis (2-amidinopropane) dihydrochloride dissolved in 5 mL of degassed water was added, and the mixture was allowed to stand for 12 hours in an adiabatic system. The obtained gel was cut and vacuum dried at 50 ° C. for 12 hours. The obtained dry gel was swollen with water, ethanol, dimethylsulfoxide and the like. In addition, the content of the polymer dissolved in deionized water may be adjusted to G
Quantitative analysis by PC, the content is 0.3% by weight
Was less than.

Example 2 Instead of tetraallyloxyethane in Example 1,
The same operation was performed except that pentaerythritol tetraallyl ether synthesized by an etherification reaction from pentaerythritol and allyl chloride was used. The obtained dried gel had a water-soluble polymer content of less than 0.3% by weight, and maintained the shape of the gel.

Example 3 Instead of tetraallyloxyethane in Example 1,
The same operation was performed except that divinyl adipate (manufactured by Tokyo Kasei) was used. The obtained dried gel had a water-soluble polymer content of less than 0.3% by weight, and maintained the shape of the gel.

Example 4 Instead of N-vinylacetamide in Example 1, N
The same operation was performed except that -methyl-N-vinylacetamide was used. The obtained dried gel had a water-soluble polymer content of less than 0.3% by weight, and maintained the shape of the gel.

Example 5 Instead of N-vinylacetamide in Example 1, N was used.
-A similar operation was performed except that vinylformamide was used. The obtained dried gel had a water-soluble polymer content of less than 0.3% by weight, and maintained the shape of the gel.

Example 6 120 g of N-vinylacetamide and tetraallyloxyethane were placed in a four-liter 1 L separable flask equipped with a nitrogen inlet tube, a thermometer, an exhaust tube and a stir bar in a bath maintained at 40 ° C. 300 mg and 2.4 g of hydroxyethyl cellulose (manufactured by Fuji Chemical Co., Ltd.) were dissolved in 180 g of ion-exchanged water, and nitrogen was introduced into the system at 1 L / min for about 1 hour to degas. Separately, 0.6 g of sorbitan monostearate was dispersed in 300 g of cyclohexane that had been degassed beforehand, and the temperature was about 40 ° C.
After being heated and dissolved in the solution, the solution was transferred to a separable flask containing the above-mentioned aqueous solution under nitrogen. Then, 360 mg of 2,2′-azobis (2-amidinopropane) dihydrochloride dissolved in 10 mL of degassed water was added to 300 rp.
It was stirred at m for 6 hours. After the completion of heating and stirring, the content was filtered off and the solid content was vacuum dried at 80 ° C. for 12 hours. The obtained dry fine particles were in the form of beads having a particle size of 100 to 300 μm, and the polymer dissolved in water was a good gel containing less than 0.3% by weight.

Example 7 The same operation as in Example 6 was conducted except that diallyl terephthalate was used instead of tetraallyloxyethane. The resulting dry gel has a polymer soluble in water of 0.
It was less than 3% by weight, and the shape of the gel was maintained.

Example 8 The same operation as in Example 6 was carried out except that pentaerythritol triallyl ether was used instead of tetraallyloxyethane. The obtained dried gel had a water-soluble polymer content of less than 0.3% by weight, and maintained the shape of the gel.

Example 9 The same operation as in Example 1 was conducted except that 250 g of N-vinylacetamide was replaced with a mixture of 175 g of N-vinylacetamide and 75 g of sodium acrylate. The obtained dried gel had a water-soluble polymer content of less than 0.3% by weight, and maintained the shape of the gel.

Example 10 In Example 1, a mixture of 175 g of N-vinylacetamide and 75 g of sodium acrylate was used in place of 250 g of N-vinylacetamide, and pentaerythritol triallyl ether was used in place of tetraallyloxyethane. The same operation was performed except that it was present. The obtained dried gel had a water-soluble polymer content of less than 0.3% by weight, and maintained the shape of the gel.

Example 11 The same operation as in Example 6 was carried out except that a mixture of 80 g of N-vinylacetamide and 40 g of sodium acrylate was used in place of 120 g of N-vinylacetamide. The obtained dried gel had a water-soluble polymer content of less than 0.3% by weight, and maintained the shape of the gel.

Example 12 In Example 6, a mixture of 80 g of N-vinylacetamide, 30 g of sodium acrylate and 10 g of acrylamido-2-methylpropanesulfonic acid was used in place of 120 g of N-vinylacetamide, and 300 mg of tetraallyloxyethane was used. Instead of diallyl adipate 200m
The same operation was performed except that 70 mg of g, N, N′-methylenebisacrylamide was used. The obtained dried gel had a water-soluble polymer content of less than 0.3% by weight, and maintained the shape of the gel.

Example 13 In Example 6, instead of N-vinylacetamide,
The same operation was performed except that N-vinylformamide was used. The resulting dry gel has a water-soluble polymer content of 0.3.
It was less than wt% and maintained the shape of the gel.

Comparative Example 1 The same operation as in Example 1 was carried out except that N, N′-methylenebisacrylamide was used instead of tetraallyloxyethane. 99% by weight of the obtained polymer was soluble in water.

Comparative Example 2 The same operation as in Example 1 was carried out except that ethylene glycol diacrylate was used instead of tetraallyloxyethane. 99% by weight of the obtained polymer was soluble in water.

Comparative Example 3 The same operation as in Example 1 was carried out except that trimethylolpropane triacrylate was used instead of tetraallyloxyethane. 99% by weight of the obtained polymer was soluble in water.

Comparative Example 4 The same operation as in Example 6 was carried out except that N, N'-methylenebisacrylamide was used instead of tetraallyloxyethane. 99% by weight of the obtained polymer was soluble in water.

Comparative Example 5 The same operation as in Example 6 was carried out except that trimethylolpropane triacrylate was used instead of tetraallyloxyethane. 99% by weight of the obtained polymer was soluble in water.

Comparative Example 6 The same operation as in Example 9 was carried out except that ethylene glycol diacrylate was used instead of tetraallyloxyethane. 59% by weight of the obtained polymer was soluble in water.

Comparative Example 7 The same operation as in Example 11 was carried out except that N, N'-methylenebisacrylamide was used instead of tetraallyloxyethane. 63% by weight of the obtained polymer was soluble in water.

Comparative Example 8 The same operation as in Example 1 was carried out except that N, N'-butylenebis (N-vinylacetamide) was used instead of tetraallyloxyethane. The obtained dried gel had a water-soluble polymer content of 1.0% by weight and maintained the shape of the gel.

Example 14 [Measurement of liquid absorption ratio of crosslinked N-vinylacetamide homopolymer to organic solvent] Liquid absorption of crosslinked N-vinylacetamide homopolymer prepared in Example 1 to various organic solvents The magnification is shown in Table 1. As a comparative example, a sodium acrylate homopolymer crosslinked product (Comparative Example 9) and an N-vinylacetamide homopolymer crosslinked product using the bis (N-vinylcarboxylic acid amide) produced in Comparative Example 8 as a crosslinking agent. The liquid absorption ratio is shown in the table. As can be seen from the table, the liquid absorption performances of the crosslinked polymers produced in Example 1 and Comparative Example 8 were at the same level, and were extremely high as compared with the performance of the sodium acrylate homopolymer crosslinked product. . In addition, the liquid absorption ratio was obtained by dispersing 0.5 g of the gel pulverized into 32 to 100 mesh in 200 mL of each solvent and leaving it to stand for 2 hours, then 2
The gel was filtered through a 00 mesh wire net, and the weight of the swollen gel was weighed. However, the liquid absorption ratio is given by the following formula. Liquid absorption ratio = (weight of swollen gel-weight of dry gel) /
(Dry gel weight)

[0046]

[Table 1]

Example 15 [Measurement of Liquid Absorption Capacity of N-Vinylcarboxylic Acid Amide (Co) Polymer Crosslinked Product to Aqueous Solution Containing Electrolyte] Examples 1 to 1
Regarding the N-vinylcarboxylic acid amide (co) polymer crosslinked product produced in 3, the liquid absorption capacity for physiological saline, saturated (27% by weight) saline, and artificial urine was measured. Table 2 shows the results. As comparative examples, sodium acrylate homopolymer crosslinked product (Comparative Example 9) and bis (N- produced in Comparative Example 8 were used.
Vinylcarboxylic acid amide) as a cross-linking agent
The liquid absorption capacity of the crosslinked vinylacetamide homopolymer is shown in the same table. As can be seen from the table, the liquid-absorbing performances of the cross-linked polymers produced in Examples 1 to 13 and Comparative Example 8 are at the same level, and are significantly higher than that of the sodium acrylate homopolymer cross-linked product. it was high. The composition of artificial urine is as follows. Urea: 20 g / L, sodium chloride: 8.2 g / L, potassium sulfate: 2.04 g / L, magnesium sulfate: 1.
14 g / L, calcium chloride: 0.64 g / L

[0048]

[Table 2]

Example 16 [Weather resistance test of N-vinylcarboxylic acid amide (co) polymer crosslinked product in swollen state] With respect to the N-vinylcarboxylic acid amide (co) polymer crosslinked product produced in Example 1, Table 3 shows the results of evaluating the weather resistance in the swollen state. As comparative examples, sodium acrylate homopolymer crosslinked products (Comparative Example 9) and N-vinylacetamide homopolymer crosslinked products using bis (N-vinylcarboxylic acid amide) produced in Comparative Example 8 as a crosslinking agent. The liquid absorption ratio is shown in the table. As can be seen from the table, the weather resistance of the crosslinked polymers produced in Example 1 and Comparative Example 8 was at the same level, and was significantly higher than the weather resistance of the sodium acrylate homopolymer crosslinked product. . The weather resistance was evaluated as follows. -Evaluation of weather resistance (UV irradiation test) 100-400 mg of the gel is weighed in a 100 mL beaker, swollen with ion-exchanged water, and then 100 V, 15 W
30 cm below the UV lamp of. After a certain period of time, the absorption capacity of the gel was measured.

[0050]

[Table 3]

Example 17 [Measurement of Liquid Absorption Capacity of Cross-Linked N-Vinylcarboxylic Acid Amide (Co) Polymer with Aqueous Solution Containing Calcium Ion] N-vinylcarboxylic acid amide (co) polymer produced in Examples 1 to 5 Saturation (0.16% by weight) of the combined crosslinked product
The liquid absorption ratio to a calcium hydroxide aqueous solution and a 10 wt% calcium chloride aqueous solution was measured. The results are shown in Table 4.
As comparative examples, sodium acrylate homopolymer crosslinked products (Comparative Example 9) and N-vinylacetamide homopolymer crosslinked products using bis (N-vinylcarboxylic acid amide) produced in Comparative Example 8 as a crosslinking agent. The liquid absorption ratio is shown in the table. As can be seen from the table, Examples 1 to 5 and Comparative Example 8
The liquid absorption performance of the crosslinked polymer produced in 1. was at the same level, and was extremely high as compared with the performance of the crosslinked product of the sodium acrylate homopolymer.

[0052]

[Table 4]

Example 18 The water in the absorbent gel in the crosslinked polymer of the present invention can be reused by plants, and the water is gradually released, and not only simple water but also a fertilizer solution having a practical concentration. Since it can absorb and release (water supply) water containing inorganic and organic ionic components, it can be used not only for fertilization, soil improvement, artificial medium, etc., but especially for planting and planting in mountains where water is inconvenient. It is convenient for water retention / water supply when transplanting seedlings, turf, etc. for remediation of dust in the ground, etc., or for revegetation in the desert, etc. By the way, conventionally commercially available so-called water-swellable cross-linked polymers have extremely low absorption rate of water containing ionic components, and even if gelled with water that does not contain ions in advance, the water in the gel is usable by plants. It is difficult to use as described above because it is bad and sometimes causes drug damage. Hereinafter, a typical example will be shown and specifically described. In this test, the crosslinked polymer produced in Example 1, as a comparative example, a crosslinked product of a sodium acrylate homopolymer (Comparative Example 9), and the bis (N-vinylcarboxylic acid amide produced in Comparative Example 8) ) Was used as a cross-linking agent, and N-vinyl acetamide homopolymer cross-linked product and agar were used. 1) A gel prepared by adding 1% by weight of each of a cross-linked polymer or agar to distilled water and mixing them uniformly was placed in a group of petri dishes (diameter 10 cm), on which edible millet and lettuce seeds were placed. , And the effects on germination, rooting and growth were investigated by leaving it in a greenhouse. Gel of Example 1, Comparative Example 8
No significant difference was observed in germination, rooting and growth of the gel and the agar gel. On the other hand, in the gel of Comparative Example 9, germination and rooting were significantly inhibited, and the growth was also very poor.

2) A group of pots (15 cm in diameter) were filled with a fixed amount of sand containing 1% by weight of each crosslinked polymer and seeded with wheat seeds, allowed to stand in a greenhouse and irrigated every day. Five weeks after thinning and sowing, the plant height of standard seedlings is about 1
When it reached about 0 cm, the last water was supplied and the water was left as it was, and the wilting condition of the seedlings was investigated. In the pots containing the cross-linked polymers of Example 1 and Comparative Example 8, wilting started on the 9th day after the water was cut off. On the other hand, in the pot containing the cross-linked polymer of Comparative Example 9, wilting started on the 4th day after the water was stopped, and in the pot containing no cross-linked polymer, the wilting started on the 3rd day after the water was stopped.

Example 19 When an aqueous solution or suspension containing reaction components (metal ions, oxides, etc.) is brought into contact with the crosslinked polymer of the present invention, a gel containing the aqueous solution is produced, which is dried and heated and baked. By doing so, the crosslinked polymer component is decomposed and vaporized, and the number of the components (metal oxide) incorporated in the matrix of the crosslinked polymer is several n.
Obtained as fine particles of about m. If the heating and calcination are performed in a non-oxidizing atmosphere, fine particles of a mixture or reaction product with carbon in the crosslinked polymer component can be obtained. Further, even for a component such as aluminum chloride that is vaporized by heating, the aqueous solution may be once gelled, then reacted with ammonium hydroxide to be converted into aluminum hydroxide in the gel, and this may be heated and baked. Further, some of the alumina sol and silica sol are suspended in water as fine particles of about several nm, but like the dissolved components such as metal ions, they can be incorporated into the matrix of the crosslinked polymer as a liquid-absorbing gel. On the other hand, in order to obtain a ceramic article other than powder, the absorbent gel may be molded and then heated and baked. In this case, contrary to the case where fine powder particles are obtained, it is necessary to cause strong coagulation, and accordingly, it is necessary to increase the temperature and the time for heating and firing depending on the case.

In any case, it can be realized by using the crosslinked polymer of the present invention which has the ability to absorb an aqueous solution containing an ion or a colloidal solution as it is and gelate it. A typical example will be specifically described below. 1) 10 g of _{Al (NO 3) 3 · 9H} 2 O water 25m
1 g of the cross-linked polymer prepared in Example 1 dissolved in L
Is added and mixed uniformly to form a gel, which is sufficiently dried and placed in an alumina crucible, heated to 1000 ° C. in an argon stream in about 6 hours, and further heated to 1000 ° C. for 6 hours. Baked. After cooling, the contents are taken out and the specific surface area s
A (BET method), α-formation rate (X-ray diffraction method), and median particle diameter d ₅₀ (centrifugal sedimentation method) were measured, and sA: 20
(5) m ² / g, α-ized rate: 95 (90)%, d ₅₀ : 0.
It was 2 (1) μ and almost no condensation due to heating was observed. The values in parentheses are measured values when no crosslinked polymer was used. Further to the above, d ₅₀ :
When a similar test was performed by adding 10 mg of 0.05 μm α-alumina fine particles, sA: 18 (3) m ² / g, α
The conversion was 100 (95)% and the d _{50 was} 0.2 (1) μ. The values in parentheses are measured values when no crosslinked polymer was used.

2) 1.6 g of boehmite, 20 mg of α-alumina (d ₅₀ : 0.05 μ), and 0.1 g of 68% nitric acid were added to 18 mL of water to prepare an alumina sol. The combined product (1 g) was added and uniformly mixed to form a gel, which was dried and put in an alumina crucible and heated to 1000 ° C. in an argon stream for about 6 hours.
It was further heated and baked for 6 hours. The physical properties of the obtained powder are sA:
It was 39 m ² / g, α-formation ratio: 92%, and d ₅₀ : 0.08 μ. 3) A gel prepared in the same manner as in 2) above is thoroughly kneaded and extruded with a syringe through a needle of about 700μ to form a filament, which is dried and then heated in a muffle furnace at 1300 ° C in the air for about 1 minute to be calcined. A filamentous alumina having a thickness of 200 μ was obtained.
Also, when the crosslinked polymer produced in Comparative Example 8 is used,
A similar filamentous alumina was obtained.

Example 20 The strength of concrete or mortar products generally depends on the water / cement ratio of the cement composition. In other words, it is known that the strength after casting and hardening increases when the amount of water is reduced as much as possible. However, in the actual site, reducing the amount of water reduces the fluidity of the cement composition,
That is, since the workability is lowered, the water / cement ratio is naturally limited. A water-reducing agent is used to solve this problem, and although it can produce some strength, it is not yet satisfactory. Excess water of the concrete and mortar composition floats on the concrete and mortar after being cast as breathing water. Therefore, the concrete / mortar upper part has a large water / cement ratio, and the strength decreases as it goes to the upper part. Also, the breathing water will not proceed to the next process unless it is eliminated, so the construction period will be lengthened. Therefore, a method has been proposed in which excess water is taken using an absorbent, and the absorbed gel gradually releases water inside the concrete to perform internal wet curing, but currently commercially available water absorbents have ionic components, especially Since it hardly absorbs an aqueous solution containing a polyvalent ion component such as calcium ion, it cannot exert a sufficient effect. However, as is clear from the absorption performance table, the crosslinked polymer of the present invention absorbs even a saturated aqueous solution of calcium hydroxide, which is the main component of cement, and can be used as described above.

Further, the cement composition containing the crosslinked polymer of the present invention is unlikely to cause a rapid dry-out upon hardening, and prevents the occurrence of cracks due to the wet curing effect, thereby increasing the strength and dimensional change. The rate is improved. In addition to the method of mixing with the concrete and mortar composition, there is also a method of producing an absorbent sheet using the crosslinked polymer of the present invention and covering it on the concrete and mortar after casting. In this method, the absorbent sheet absorbs breathing water and is in close contact with the driving surface, so that the strength is increased by the wet curing effect. Further, by curing the mortar composition containing the crosslinked polymer of the present invention, it is possible to leave the gelled portion as voids and consequently reduce the density of the mortar (weight reduction of the mortar). By the way, the currently available water-absorbing agent hardly absorbs the aqueous solution containing the polyvalent ion component, so there are few voids in the mortar,
The above usage is difficult. In any case, the effect is exhibited by using the crosslinked polymer of the present invention having the ability to absorb the saturated aqueous solution of calcium hydroxide.

1) Ordinary Portland cement (manufactured by Nippon Cement) 300 kg, tap water 225 kg, fine aggregate 67
In a concrete composition having a composition of 0.6 kg and 1031.1 kg of coarse aggregate, each of Example 1, Example 9, Comparative Example 8 and sodium acrylate crosslinked polymer (Comparative Example 9) was added.
0 g was mixed. JIS except for kneading time of 4 minutes
A 1138 "How to make concrete in a test room"
The breathing amount and breathing rate are
The compression strength was measured according to IS A 1123, and the compression strength was measured according to JIS A 1108. The respective results are shown in Table 5. As is apparent from the table, by mixing the crosslinked polymers of Example 1, Example 9 and Comparative Example 8, the breathing water was clearly reduced and the compressive strength was also improved.

[0061]

[Table 5]

2) Example 1, Example 9, Comparative Example 8 and sodium acrylate cross-linked polymer (Comparative Example 9) were uniformly sprinkled on a non-woven fabric at 26.5 g / m ² respectively, and a non-woven fabric was formed thereon. I put it on. The absorbent sheet was cast on concrete after casting to prepare a test piece. The mix of this concrete is normal Portland cement (made by Nippon Cement) 300K
g / m ³ , tap water 225 kg / m ³ , fine aggregate 670.6
A kg / m ³ and coarse aggregate 1031.1Kg / m ^3, was prepared in accordance with JIS A 1138. This specimen was demolded after 7 days of age, the absorbent sheet was left as it was, and the compressive strength on the 28th and 91th days of the age was measured according to JIS A1108. The respective results are shown in Table 6. As is clear from the table, the absorbent sheets produced using the crosslinked polymers of Example 1, Example 9 and Comparative Example 8 clearly improved the compressive strength.

[0063]

[Table 6]

Example 21 The crosslinked polymer of the present invention does not significantly decrease the absorption rate even in an aqueous solution containing a large amount of calcium ions. Therefore, the hygroscopic agent containing the crosslinked polymer of the present invention absorbs a large amount of calcium chloride deliquescent solution resulting from moisture absorption, and the gelation of the crosslinked polymer causes the entire hygroscopic agent to become non-fluidized. As a result, it does not contaminate other substances.
By the way, conventionally commercially available so-called water-swellable crosslinked polymers are not suitable for the above-mentioned applications because the water absorption rate of an aqueous solution containing a polyvalent metal ion such as calcium ion is extremely lowered. The following are representative examples. 5 g, 10 g, and 50 g of the cross-linked polymer produced in Example 1 were added to 100 g of pulverized calcium chloride (200-mesh-passing product), and mechanically mixed to obtain hygroscopic agents A, B, and C. It was Also, Comparative Example 8 was added to 100 g of pulverized calcium chloride.
Hygroscopic agent D was prepared by adding 10 g of the cross-linked polymer prepared in
Then, 50 g of a sodium acrylate crosslinked polymer (Comparative Example 9) was added to and mixed with 100 g of a pulverized product of calcium chloride to obtain a hygroscopic agent E. 50 g of the hygroscopic agent obtained by the above formulation was left in a thermo-hygrostat (temperature 30 ° C., humidity 95%), and weight measurement after moisture absorption and morphological change were observed. The results are shown in Table 7.
It was shown to. The cross-linked polymer not added (that is, calcium chloride alone) is shown in the same table as the moisture absorbent F. As is clear from the table, the addition of the cross-linked polymer produced in Example 1 and Comparative Example 8 clearly eliminated the fluidity of the hygroscopic agent.

[0065]

[Table 7]

Example 22 The crosslinked polymer of the present invention has almost no decrease in the liquid absorption rate with respect to body fluids containing a large amount of salts (urine, menstrual blood), and thus can be used for sanitary products such as disposable diapers and sanitary napkins. . Conventional commercially available so-called water-swellable crosslinked polymer, the paper diaper containing the crosslinked polymer of the present invention has a large urine absorption capacity,
As a result, the amount of the cross-linked polymer required to absorb the same amount of urine can be reduced, and thus it can be said that the body fluid absorbent is suitable for the above-mentioned use. The basic form of sanitary goods is 1. Liquid-permeable topsheet, 2. 2. Absorption layer (crosslinked polymer, cotton pulp, etc.), 3. A breathable waterproof sheet. Among them, the crosslinked polymer of the present invention is used for the absorption layer. There are many shapes of this absorption layer,
Typical examples include those in which a crosslinked polymer is dispersed on a nonwoven fabric, and those in which the crosslinked polymer is sandwiched between the nonwoven fabrics. The absorption capacity was measured in a form close to these. The method for measuring the absorption capacity is shown below.

0.4 g of each of the crosslinked polymers prepared in Examples 1, 9 and Comparative Example 8 and the sodium acrylate crosslinked polymer (Comparative Example 9) were evenly distributed on a 165 × 60 mm tissue paper. After spraying, a piece of tissue paper was placed on it, lightly pressed and sprayed with water (the amount of spraying was appropriate). Next, it was pressed by an embossing roller heated to about 140 ° C. Since the embossing roller alone was not sufficient for drying, it was further vacuum dried at 80 ° C. for 2 hours. This sheet was placed on a wire mesh and immersed in artificial urine whose liquid temperature was 30 ° C. After 1 hour, the sheet was taken out together with the wire mesh, tilted at 45 °, drained for 1 minute, and then weighed. The respective results are shown in Table 8. As is apparent from the table, the sheets prepared from the crosslinked polymers prepared in Examples 1 and 9 and the sheet prepared from the crosslinked polymer prepared in Comparative Example 8 have the same liquid absorption performance. Moreover, the performance was extremely higher than that of the crosslinked product of the homopolymer of sodium acrylate.

[0068]

[Table 8]

Example 23 90 parts by weight of the crosslinked N-vinylacetamide homopolymer prepared in Example 1 and 10 parts by weight of cellulose powder having a particle size of 75 to 150 μm (filter paper powder A type manufactured by Toyo Roshi Kaisha, Ltd.) were used in Henschel. A mixer was mixed for 10 minutes to obtain a liquid absorbent.
1.0 g of this liquid absorbent was enclosed in a 4 × 6 cm cotton tea bag, immersed in natural seawater at 25 ° C. for 10 minutes, then pulled up and left for 1 minute, and the adhered water was wiped off with a tissue paper. (W ₁ ) was measured. Similarly, an empty tea bag was immersed in natural seawater, left to stand, and weighed to give a blank (W ₀ ). The weight W ₁ of the tea bag including the absorbent after the absorption of the liquid, the blank W ₀ and the weight of the absorbent 1.
The liquid absorption capacity was obtained by subtracting 0 g. Liquid absorption ratio is 2
It was double.

Comparative Example 10 1.0 g of only the liquid-absorbent resin used in Example 1 was sealed in a tea bag, and the liquid-absorption capacity was measured in the same manner as in Example 23. The particles in the tea bag adhered to each other to form a so-called momako, and the liquid absorption ratio was 4 times.

Comparative Example 11 Example 23 except that fine powdery silica gel (Wakogel C-200 manufactured by Wako Pure Chemical Industries, Ltd.) was used in place of the cellulose powder.
A liquid absorbing agent was prepared with the same formulation as above, and the liquid absorption ratio was measured in the same manner. The liquid absorption ratio was 3 times.

Example 24 The liquid absorbing agent prepared in Example 1 was mixed with cotton-like pulp in a weight ratio of 25:75 to form a sheet. Rayon paper (12 g / m ² ) is laminated on one side of this sheet, and 20 on the other side.
A polyethylene film with a thickness of μm was overlaid. 50c for this
An absorbent article was obtained by cutting into a size of m × 50 cm and press-bonding the ends by heat sealing. 200 mL of natural seawater was injected into the central part of this absorbent article for 30 seconds. When the area of the wet part of the absorbent article was measured after 10 minutes, it was 1.20 m ² .

[0073]

INDUSTRIAL APPLICABILITY The N-vinylcarboxylic acid amide type crosslinked polymer according to the present invention is excellent in chemical stability and is an aqueous liquid containing not only water but also a high concentration of an electrolyte such as a metal ion.
It is a liquid swellable resin having excellent liquid absorbability with respect to a polar organic solvent such as alcohol and excellent gel strength. In addition, compared with the conventionally known N-vinylcarboxylic acid amide-based crosslinked polymer, the content of the water-soluble polymer is small, and the crosslinked polymer can be manufactured at low cost. The cross-linked polymer according to the present invention is a liquid absorbent for aqueous liquids and polar organic solvents, a water retention agent for vegetation or artificial medium, a body fluid absorbent for hygiene products, an auxiliary agent for hygroscopic agents,
It can be used in various applications such as liquid absorbents and liquid absorbent articles by mixing with powdery organic polymer substances, protein concentration (refining) materials, concrete curing and cement modifiers, dispersants for metal salt solutions. In addition, it exhibits excellent functions in various applications as compared with conventionally known polyelectrolyte-based liquid absorbents such as polyacrylic acid sodium-based liquid absorbents.

Claims (9)

[Claims] 1. An N-vinylcarboxylic acid amide represented by the following general formula [A] alone or a mixture of the N-vinylcarboxylic acid amide and a copolymerizable monomer, and two allyl groups in one molecule. A crosslinked polymer obtained by copolymerizing the above compound or a compound having two or more vinyl ester structures in one molecule, which absorbs water 10 times or more of its own weight. Embedded image [In the formula, R ¹ and R ² independently represent hydrogen or a methyl group. ] 2. An N-vinylcarboxylic acid amide represented by the general formula [A] alone or a mixture of the N-vinylcarboxylic acid amide and a monomer copolymerizable with the N-vinylcarboxylic acid amide, and 1 represented by the following general formula [B]. The molar ratio of the compound having two or more allyl groups in the molecule or the compound having two or more vinyl ester structures in one molecule is 90:10 to 99.
The crosslinked polymer according to claim 1, which is 9999: 0.0001. (Here, [B] means the following general formula [I] or [I
I]. _{) (CH 2 = CH-CH} 2 -) n -Z (I) ## STR2 ## [In the formula, n and m are integers of 2 or more, and Z and Z'represent an n-valent and m-valent organic group, respectively. ] 3. A molar ratio of the N-vinylcarboxylic acid amide represented by the general formula [A] to the monomer copolymerizable with the N-vinylcarboxylic acid amide is 50:50 to 1.
The crosslinked polymer according to claim 1 or 2, which is 00:00. 4. A liquid absorbent for an aqueous liquid and / or an organic solvent, which comprises using the crosslinked polymer according to any one of claims 1 to 3. 5. The liquid absorbent according to claim 4, wherein the organic solvent is a single liquid having a solvent polarity parameter E _T value of 45 or more or a mixed liquid having an E _T value of 43 or more. 6. Use of the crosslinked polymer according to any one of claims 1 to 3 for the preservation (supply) of vegetative or artificial medium.
Liquid medication. 7. A body fluid absorbent for hygiene products, characterized by using the crosslinked polymer according to any one of claims 1 to 3. 8. A hygroscopic agent aid comprising the crosslinked polymer according to any one of claims 1 to 3. 9. A liquid absorbent and a liquid absorbent article obtained by mixing the crosslinked polymer according to claim 1 and a powdery organic polymer substance.