JP2002363340A - Crosslinking agent for water-absorptive resin, and water- absorptive material obtained by using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crosslinking agent, particularly a surface crosslinking agent, for water-absorptive resin particles, which is excellent in safety and can crosslink water-absorptive resin particles at a low temperature to give a water-absorptive resin excellent in both water absorbency and water absorption rate. SOLUTION: The crosslinking agent comprise a combination of a first component comprising a halohydrin compound and a second component comprising at least one compound selected from vinyl ether compounds, hydroxyethylamide compounds and oxazoline compounds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cross-linking agent for cross-linking a water-absorbing resin to obtain a water-absorbing agent, a water-absorbing agent thus obtained, and a method for producing the same.

[0002]

2. Description of the Related Art Water-absorbent resins have a very high water-absorbing ability, and thus have been widely used in sanitary materials such as disposable diapers and sanitary products, as well as in food, agriculture, forestry and civil engineering. Have been.

Heretofore, a partially neutralized salt of polyacrylic acid or polymethacrylic acid has been used in many cases as a water-absorbing resin for sanitary materials.
Not only under normal pressure (under no load) but also under pressure (under load), both water absorption capacity (water absorption ratio) and water absorption speed are large, and their performance under normal pressure and under pressure is well-balanced. Is required.

Here, one means of obtaining a water-absorbing resin having a high water absorption rate is to obtain a resin having an increased crosslinking density. However, as is conventionally known, for example, in the polymerization of acrylic acid and / or a salt thereof (neutralized salt), a large amount of a polyfunctional copolymerizable monomer is used as an internal crosslinking agent. The resulting uniformly cross-linked resin has a high water absorption capacity under pressure, but is inferior in water absorption capacity under normal pressure.

As one method for solving such a problem, there has been conventionally known a method of surface-crosslinking water-absorbent resin particles. This surface cross-linking method uses water-absorbing resin particles having a carboxylic acid group and / or a carboxylic acid group as a starting material, maintains a low degree of cross-linking therein, and does not reduce the water absorbing ability. Using a cross-linking agent having at least two reactive groups (functional groups) capable of reacting with the carboxylic acid group and / or carboxylic acid group, mainly cross-linking the vicinity of the surface of the water-absorbent resin particles, By increasing the degree of crosslinking near the surface of the resin particles, a water-absorbing agent having a high water-absorbing speed is obtained.

As a surface cross-linking agent used in such a surface cross-linking method, conventionally, for example, JP-A-57-4462.
No. 7 proposes an epoxy compound represented by ethylene glycol diglycidyl ether, and JP-A-58-180223 proposes a polyhydric alcohol represented by ethylene glycol, diethylene glycol, glycerin and the like. Have been. In addition, JP-A-63-195205 discloses polyamine compounds,
A polyvalent aziridine compound and an epoxy compound having an amino group, and a reaction product of epihalohydrin with a low-molecular primary amine such as ammonia and ethylenediamine are proposed in JP-A-2-248404.

[0007]

However, when an alcohol or an amine such as glycerin is used as a cross-linking agent in the above-mentioned surface cross-linking method, the surface cross-linking reaction of the water-absorbent resin particles by the cross-linking agent is usually performed at 180 ° C. or higher. It is necessary to carry out the reaction at a high temperature. However, if the crosslinking reaction is carried out at such a high temperature, thermal crosslinking and thermal deterioration of the water-absorbent resin itself occur, so that not only is it difficult to control the degree of crosslinking, but also to obtain the obtained water absorption. On the contrary, the agent may be inferior in its water absorbing ability and water absorbing speed.

On the other hand, a crosslinking agent such as an epoxy compound such as ethylene glycol diglycidyl ether, an epoxy compound having an amino group in the molecule, an amine compound, an aziridine compound, and an isocyanate compound has relatively strong skin irritation. Therefore, when used as a cross-linking agent for a water-absorbing resin for sanitary materials that may come into direct contact with the skin of infants, etc., there is a problem in the safety when an unreacted cross-linking agent remains in the obtained water-absorbing agent. is there.

The reaction product of epihalohydrin with a low-molecular-weight primary amine such as ammonia or ethylenediamine is a product obtained by simply adding an amine to the epoxy group of epihalohydrin, and thus has an active compound in the molecule. Since it does not have any functional group, effective crosslinking cannot be performed even under heating, and the water absorption rate cannot be sufficiently improved.

The present invention has been made in order to solve the above-mentioned problems in the production of a water-absorbing agent by the conventional surface cross-linking of water-absorbent resin particles. It is an object of the present invention to provide a cross-linking agent for obtaining a water-absorbing agent by internally cross-linking a water-soluble resin, and to provide a water-absorbing agent obtained by using such a cross-linking agent and a method for producing the same. With the goal.

Preferably, the present invention has no epoxy group in the molecule, is excellent in safety, and has a further advantage as compared with the case where a conventional surface cross-linking agent composed of alcohol or amine is used.
It is an object of the present invention to provide a surface cross-linking agent for water-absorbent resin particles that efficiently crosslinks the vicinity of the surface of the water-absorbent resin particles at a lower temperature and provides a water-absorbing agent having excellent water-absorbing ability under pressure. Another object of the present invention is to provide a water absorbing agent obtained by using such a surface cross-linking agent and a method for producing the same.

The present invention also provides a water-absorbing resin internal crosslinking agent for obtaining a water-absorbing agent by internal crosslinking of the water-absorbing resin, a water-absorbing agent obtained by using such an internal crosslinking agent, and a method for producing the same. The purpose is to:

[0013]

According to the present invention, (A)
General formula (I)

[0014]

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(Wherein, X represents a chlorine atom or a bromine atom, and R ₁ represents a hydrogen atom or an alkyl group.) A first compound comprising a halohydrin compound having at least two halohydrin groups D in the molecule. Component and (B) (B1)
General formula (II)

[0016]

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Wherein R ₂ is independently a hydrogen atom,
It represents an alkyl group, an aryl group or a halogen atom. A) a compound having at least two vinyl ether groups E in the molecule, or a compound having at least one vinyl ether group E in the molecule, a hydroxyl group, an amino group, and a compound represented by the general formula (III):

[0018]

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Wherein R ₃ is independently a hydrogen atom,
Represents an alkyl group, an aryl group or a halogen atom, and r is 0 or 1. A) a vinyl ether compound having at least one reactive group J selected from an alkylene carbonate group G represented by
1) and (B2) a general formula (IV)

[0020]

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[0021] (wherein, R ₄ each independently represent a hydrogen atom or a methyl group.) With hydroxyethyl amide compound having at least two hydroxyethyl amide groups K represented in the molecule with, (B3) the general formula (V)

[0022]

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(Wherein R ₅ each independently represents a hydrogen atom or a methyl group.)
And at least one selected from oxazoline compounds having at least two in the molecule.

In particular, according to the present invention, there is provided a water-absorbing resin surface cross-linking agent which can be suitably used for surface cross-linking of a water-absorbing resin.

According to the present invention, 0.001 to 20 parts by weight of the above-mentioned water-absorbent resin crosslinking agent is added to 100 parts by weight of a water-absorbent resin having a carboxylic acid group and / or a carboxylic acid group,
A water absorbing agent obtained by heating and crosslinking is provided.

Further, according to the present invention, 0.001 to 20 parts by weight of the above water-absorbing resin crosslinking agent is added to 100 parts by weight of a water-absorbing resin having a carboxylic acid group and / or a carboxylic acid group,
There is provided a method for producing a water-absorbing agent, which comprises heating and crosslinking.

In particular, according to the present invention, 0.001 to 20 parts by weight of the above-mentioned water-absorbing resin crosslinking agent is added to 100 parts by weight of the water-absorbing resin particles having a carboxylic acid group and / or a carboxylic acid salt group. And a surface-crosslinked water-absorbent resin obtained by heating.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION The water-absorbent resin cross-linking agent (hereinafter simply referred to as a cross-linking agent) according to the present invention is suitably used as a surface cross-linking agent for obtaining a water-absorbing agent by surface-cross-linking water-absorbent resin particles. However, it can also be used as an internal crosslinking agent.

According to the present invention, when water-absorbing resin particles are used as a starting material and the surface is cross-linked with the cross-linking agent of the present invention to obtain a water-absorbing agent, the water-absorbing resin particles are
Any conventionally known water-absorbing resin particles having a carboxylic acid group and / or a carboxylic acid group and absorbing water and swelling to form a hydrogel can be used. Accordingly, specific examples include, for example, a crosslinked product of partially neutralized polyacrylic acid, a partially neutralized product of self-crosslinked polyacrylic acid, a crosslinked product of starch-acrylate graft copolymer, and a crosslinked product of starch-acrylonitrile graft copolymer. Product, vinyl alcohol-acrylate copolymer crosslinked product, acrylate-acrylamide copolymer crosslinked product, acrylate-acrylonitrile copolymer crosslinked product, acrylate and 2- Copolymerized crosslinked products of acrylamide-2-methylpropanesulfonic acid salt and the like can be mentioned. These are used alone or as a mixture of two or more.

In the present invention, in particular, from the viewpoint of the water absorbing performance of the obtained water absorbing agent, the water absorbing resin particles as a starting material include a water absorbing resin having a carboxylic acid group and / or a carboxylic acid group at a high density. Particles, that is, particles composed of a partially neutralized acrylic acid partially crosslinked product or a partially neutralized self-crosslinked polyacrylic acid are preferred. Here, examples of the carboxylate include a sodium salt, a potassium salt, an ammonium salt and the like, and a sodium salt is particularly preferable.

In the present invention, the method of producing and the shape of the water-absorbent resin particles are not particularly limited, and the pearl-shaped water-absorbent resin particles obtained by the inverse suspension polymerization method and the dried product after the aqueous solution polymerization are used. A flaky, massive, rocky, granular, amorphous, water-absorbent resin or the like obtained by pulverization is used. Further, the water-absorbent resin particles may be those obtained by granulating these water-absorbent resin particles.

The particle size of the water-absorbing resin particles is not particularly limited, but is usually in the range of 40 to 140 mesh. However, when used in sanitary articles such as disposable diapers, fine particles having a large surface area have a too high water absorption rate, impeding the diffusion of urine to the side, and the fine particles form a pulp forming a base material of the sanitary article. Preferably, particles having a particle size of 20 to 60 mesh have 70% by weight or more of the entirety, particularly preferably, because it is easy to come off from the layer.
Particles having a particle size of 20 to 42 mesh have a weight percentage of 70% by weight or more.

The cross-linking agent according to the present invention is particularly useful as a surface cross-linking agent for effectively cross-linking the vicinity of the surface of the water-absorbent resin particles as described above.

The crosslinking agent according to the present invention comprises (A) a compound of the general formula (I)

[0035]

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(Wherein, X represents a chlorine atom or a bromine atom, and R ₁ represents a hydrogen atom or an alkyl group.) A first compound comprising a halohydrin compound having at least two halohydrin groups D in the molecule. Component and (B) (B1)
General formula (II)

[0037]

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Wherein R ₂ is independently a hydrogen atom,
It represents an alkyl group, an aryl group or a halogen atom. A) a vinyl ether compound having at least two vinyl ether groups E in the molecule, or at least one vinyl ether group E in the molecule;
Amino group and general formula (III)

[0039]

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Wherein R ₃ is independently a hydrogen atom,
Represents an alkyl group, an aryl group or a halogen atom, and r is 0 or 1. A) a vinyl ether compound having at least one reactive group J selected from an alkylene carbonate group G represented by
1) and (B2) a general formula (IV)

[0041]

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[0042] (wherein, R ₄ each independently represent a hydrogen atom or a methyl group.) With hydroxyethyl amide compound having at least two hydroxyethyl amide groups K represented in the molecule with, (B3) the general formula (V)

[0043]

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(Wherein R ₅ each independently represents a hydrogen atom or a methyl group.)
And at least one second component selected from oxazoline compounds having at least two in the molecule.

That is, according to the present invention, together with the first component comprising the halohydrin compound (A), it is selected from the vinyl ether compound (B1), the hydroxyethylamide compound (B2), and the oxazoline compound (B3). By combining a second component comprising at least one compound and using this as a surface cross-linking agent for the water-absorbent resin particles, the water-absorbent resin particles can be cooled at a lower temperature as compared with the case where a conventional surface cross-linking agent is used. Can efficiently crosslink in the vicinity of the surface, and can obtain a water-absorbing agent having excellent water-absorbing ability under normal pressure, in particular, under pressure. (First Component of Crosslinking Agent) First, the first component of the crosslinking agent according to the present invention
The halohydrin compound as a component will be described.

In the crosslinking agent according to the present invention, the first component, the halohydrin compound (A), has the general formula (I)

[0047]

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(In the formula, X represents a chlorine atom or a bromine atom, and R ₁ represents a hydrogen atom or an alkyl group.) A compound having at least two halohydrin groups D in a molecule.

According to the present invention, the halohydrin compound (A) is preferably a first halohydrin compound, a second halohydrin compound or a combination (mixture) thereof.

The first halohydrin compound is represented by (A1
a) General formula (VI)

[0051]

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[0052] (In the formula, R ₆ is 2 to 10 carbon atoms (k +
m) a valent aliphatic hydrocarbon group, X represents a chlorine atom or a bromine atom, k and m are 2 ≦ k ≦ 6, 0 ≦ m ≦ 4,
It is an integer satisfying 2 ≦ k + m ≦ 6. (A1a) represented by the general formula (VII):

[0053]

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Wherein R ₇ represents a hydrogen atom or a methyl group, X represents a chlorine atom or a bromine atom, and n is an integer of 1 to 50. A1
c) General formula (VIII)

[0055]

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Wherein R ₈ is a hydrogen atom or 3-halo-2
A hydroxy-group, wherein at least two of R ₈ are 3-halo-2-hydroxypropyl groups;
p is an integer of 1 to 10. (A1)
c) at least one selected from

In the halohydrin compound (A1c) represented by the general formula (VIII), the halogen atom is a chlorine atom or a bromine atom.

Such a first halohydrin compound is
Generally, the halohydrin compounds (A1a), (A1
Corresponding to b) or (A1c), it can be obtained by reacting a compound having at least two hydroxyl groups in the molecule (hereinafter referred to as a polyhydroxy compound) with epihalohydrin.

That is, the first halohydrin compound (A1
In order to obtain a), the above polyhydroxy compound is represented by the general formula (XIX)

[0060]

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(Wherein R ₆ , k and m are the same as those described above), and can be obtained by reacting this with an epihalohydrin. The aliphatic hydrocarbon group R ₆ is an aliphatic polyhydric alcohol residue, as is apparent from specific examples of the polyhydric alcohol described below.

To obtain the second hydrin compound (A1b), the polyhydroxy compound represented by the general formula (XX)

[0063]

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(Wherein R ₇ and n are the same as those described above), and can be obtained by reacting this with epihalohydrin. In the polyhydric alcohol represented by the general formula (XX), R ₇ is preferably a hydrogen atom, and n is preferably 1 or 2, and particularly preferably 2.

Further, a third halohydrin compound (A1
In order to obtain c), the polyhydroxy compound represented by the general formula (XXI)

[0066]

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(Wherein p is as defined above) and can be obtained by reacting this with an epihalohydrin. In the polyhydric alcohol represented by the general formula (XXI), p is preferably 1.

The polyhydric alcohol represented by the general formula (XIX) is not particularly limited, but includes, for example, 1,2-propanediol, 1,3-propanediol, 1,2-butane Diol, 1,4-butanediol, 1,
Examples thereof include 6-hexanediol, glycerin, trimethylolethane, trimethylolpropane, erythritol, pentaerythritol, and sorbitol. Among these, trimethylolethane or sorbitol is particularly preferred.

The polyhydric alcohol represented by the general formula (XX) is not particularly limited, but includes, for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, Examples thereof include polypropylene glycol. Of these, diethylene glycol or dipropylene glycol is particularly preferred.

The polyhydric alcohol represented by the general formula (XXI) is not particularly limited, but
For example, diglycerin, polyglycerin and the like can be mentioned. Among these, diglycerin is particularly preferred.

On the other hand, as the epihalohydrin to be reacted with such a polyhydric alcohol, epichlorohydrin or epibromohydrin is particularly preferably used.

The reaction between the polyhydric alcohol and epihalohydrin may be carried out, if necessary, in a reaction solvent in the presence of a Lewis acid catalyst, preferably under heating (for example, 30 ° C.).
(Temperature in the range of ９５95 ° C.), by adding epihalohydrin dropwise to the polyhydric alcohol and mixing. Examples of the Lewis acid catalyst include, but are not limited to, boron trifluoride etherate, tin tetrachloride, zinc borofluoride, titanium tetrachloride, zinc chloride, silica alumina, antimony pentachloride, and the like. It is not something to be done.

The above-mentioned reaction solvent is used as necessary for controlling the reaction and adjusting the viscosity, etc., as long as it is inert in the reaction between the above-mentioned polyhydric alcohol and epihalohydrin. Such a thing may be used. Therefore, as such a reaction solvent, for example, toluene,
Examples thereof include aromatic hydrocarbons such as xylene, aliphatic hydrocarbons such as hexane and heptane, and ethers such as diethyl ether, diisopropyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and dioxane.

In such a reaction between a polyhydric alcohol and epihalohydrin, epihalohydrin is usually added to the amount of hydroxyl groups of the polyhydric alcohol by 30%.
To 200 mol%, preferably 50 to 150 mol%. The amount of epihalohydrin used is 30 mol% based on the amount of hydroxyl groups of the polyhydric alcohol.
When less than, the amount of halohydrin groups in the resulting polyhalohydrin compound is too low, and using this as a crosslinking agent to perform surface crosslinking of the water-absorbing resin particles, the crosslinking efficiency is low, and the water-absorbing resin particles Water absorption performance cannot be sufficiently improved. However, when the use amount of epihalohydrin exceeds 200 mol%, unreacted epihalohydrin remains in the obtained halohydrin compound, which is not only uneconomical but also used as a surface cross-linking agent for the water-absorbent resin particles. This is not preferable from the viewpoint of safety.

According to the present invention, such a first halohydrin compound (A1a), (A1b) or (A1c)
Is a single component or a mixture of two or more components, each of which is described below as a second component, that is, a vinyl ether compound (B1)
And a combination of at least one selected from a hydroxyethylamide compound (B2) and an oxazoline compound (B3) is used as a water-absorbing resin crosslinking agent.

In the crosslinking agent according to the present invention, the second halohydrin compound is represented by the following formula (A2):

[0077]

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Wherein A is an alkylene group having 2 to 8 carbon atoms or a group represented by the general formula (X)

[0079]

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[0080] (wherein, R ₁₀ represents a hydrocarbon group having 1 to 4 carbon atoms, s is an integer of 1-3.) Shows a divalent group M represented by, R ₉ are each independently X represents a hydrocarbon group having 1 to 4 carbon atoms; X represents a chlorine atom or a bromine atom;
Is an integer of up to 5. ) Is an epihalo quaternary ammonium compound having two or more quaternary ammonium groups and 3-halo-2-hydroxypropyl groups in the molecule.
Here, the halogen atom is a chlorine atom or a bromine atom. Also, q is preferably 0, and s is preferably 1.

According to the present invention, such a second halohydrin compound (A2) also comprises a second component described later, namely, a vinyl ether compound (B1), a hydroxyethylamide compound (B2), and an oxazoline compound (B3). And used as a crosslinking agent in combination with at least one selected from

This second halohydrin compound (A2)
Is the general formula (XXII)

[0083]

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(Wherein A is an alkylene group having 2 to 8 carbon atoms or a group represented by the general formula (X)

[0085]

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[0086] (wherein, R ₁₀ represents a hydrocarbon group having 1 to 4 carbon atoms, s is an integer of 1-3.) Shows the free amino nitrogen divalent group M represented by, R ₉ Each independently represents a hydrocarbon group having 1 to 4 carbon atoms. Epihalohydrin or 1,3-dihalo-2 to the polytertiary amine compound represented by
-By reacting propanol.

For example, as described later, when N, N, N ′, N′-tetramethyl-1,2-diaminoethane is used as the polytertiary amine compound, the polytertiary amine compound 1 In the molar part epihalohydrin or 1,3-dihalo-2
-More than 2 mole parts of propanol may be reacted. When N, N, N ', N', N "-pentamethyldiethylenetriamine is used as the polytertiary amine compound, epihalohydrin or 1,3-dihalo- What is necessary is just to make 3 mol parts or more of 2-propanol react.

In the polytertiary amine compound represented by the general formula (XXII), each R ₉ independently represents a hydrocarbon group having 1 to 4 carbon atoms, and preferably (a) a carbon group having 1 carbon atom. An alkyl group having 1 to 4 carbon atoms, (b) an alkyl group having 1 to 4 carbon atoms having a hydroxyl group or a cyano group, or (c) a 1 carbon atom.
And 4 to 4 unsaturated alkyl groups, and particularly preferably a methyl group.

Accordingly, specific examples of such a polytertiary amine compound include, for example, N, N, N ′, N′-tetramethyl-1,2-diaminoethane, N, N, N ′, N ′ -Tetramethyl-
1,2-diaminopropane, N, N, N ', N'-tetramethyl-
1,3-diaminopropane, N, N, N ', N'-tetramethyl-
1,4-diaminobutane, N, N, N ', N'-tetraallyl-1,
4-diaminobutane, N, N, N ', N'-tetramethyl-1,6
-Diaminohexane, N, N, N ', N'-tetra (hydroxyethyl) -1,3-diaminopropane, N, N, N', N ', N "-pentamethyldiethylenetriamine. Among these, for example, N, N, N ', N'-tetramethyl-1,2-diaminoethane and N, N, N', N'-tetramethyl-1,6-diaminohexane are preferably used. Can be

As the epihalohydrin, epichlorohydrin or epipromhydrin is preferably used as described above. Examples of 1,3-dihalo-2-propanol include 1,3-dichloro-2-propanol and 1,3-dibromo-2-propanol.

The reaction of the above polytertiary amine compound with epihalohydrin or 1,3-dihalo-2-propanol is preferably carried out, if necessary, in a reaction solvent comprising water, a hydrophilic organic solvent or a mixture thereof. Can be carried out by adding epihalohydrin or 1,3-dihalo-2-propanol dropwise to the polytertiary amine compound under heating (for example, at a temperature in the range of 30 to 95 ° C.) and mixing. When epihalohydrin is used, the polyhalogenated tertiary amine compound is reacted with epihalohydrin in the presence of an aqueous solution of concentrated hydrochloric acid (concentrated hydrochloric acid) or concentrated hydrobromic acid in an equimolar amount or more with epihalohydrin.

Examples of the hydrophilic organic solvent include lower aliphatic alcohols such as methanol, ethanol and isopropyl alcohol, ethers such as tetrahydrofuran and dioxane, glycol esters such as ethyl cellosolve, and amides such as dimethylformamide. Can be mentioned.

In the reaction of the polytertiary amine compound with epihalohydrin or 1,3-dihalo-2-propanol, the amount of epihalohydrin or 1,3-dihalo-2-propanol used depends on the amount of the polytertiary amine compound. Third
It is usually in the range of 30 to 200 mol%, preferably 50 to 150 mol%, based on the amount of the primary amino group. Poly 3rd
When the amount of epihalohydrin or 1,3-dihalo-2-propanol used is less than 30 mol% with respect to the amount of tertiary amino groups of the tertiary amine compound, the halohydrin in the obtained epihalo quaternary ammonium compound The base amount is too low, used as a surface cross-linking agent for the water-absorbent resin particles,
Even if the surface cross-linking of the water-absorbent resin particles is performed, the cross-linking efficiency is low, and the water-absorbing performance of the water-absorbent resin particles cannot be sufficiently increased. On the other hand, when the use amount of epihalohydrin exceeds 200 mol%, unreacted epihalohydrin remains in the obtained quaternary ammonium compound, which is not only uneconomical but also causes surface crosslinking of the water-absorbent resin particles. When used as an agent, it is not preferred from the viewpoint of safety.

As described above, according to the present invention, the first halohydrin compound or the second halohydrin compound is used as the halohydrin compound as the first component. Preferably, the first halohydrin compound and the second halohydrin compound are used. 2
Is used in combination with the halohydrin compound.

As described above, when the first halohydrin compound and the second halohydrin compound are used in combination as the first component composed of the halohydrin compound (A), their ratio is not particularly limited. However, it is preferable that the first water-absorbing agent be composed of 10 to 90% by weight of the first halohydrin compound and 90 to 10% by weight of the second halohydrin compound, so that the obtained water-absorbing agent has an excellent balance between the water absorption rate and the water absorbing ability. , The first halohydrin compound 40
Preferably, the second halohydrin compound comprises 60 to 40% by weight and 60 to 40% by weight. (Second Component of Crosslinking Agent) Next, the second component of the crosslinking agent according to the present invention will be described. In the present invention, the second component is represented by the following general formula (II):

[0096]

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[0097] (wherein, R ₂ each independently represent a hydrogen atom,
It represents an alkyl group, an aryl group or a halogen atom. A) a vinyl ether compound having at least two vinyl ether groups E in the molecule, or at least one vinyl ether group E in the molecule;
Amino group and general formula (III)

[0098]

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Wherein R ₃ is independently a hydrogen atom,
Represents an alkyl group, an aryl group or a halogen atom, and r is 0 or 1. A) a vinyl ether compound (B1) having at least one reactive group J selected from an alkylene carbonate group G represented by the formula (B1):

[0100]

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(Wherein R ₄ independently represents a hydrogen atom or a methyl group.) A hydroxyethylamide compound (B2) having at least two hydroxyethylamide groups K in the molecule, and (B3 ) General formula (V)

[0102]

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(Wherein, R ₅ independently represents a hydrogen atom or a methyl group.)
And at least one oxazoline compound (B3) having at least two in the molecule. (Vinyl ether compound in the second component) According to the present invention, the vinyl ether compound (B1) has the general formula (II)

[0104]

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(Wherein R ₂ is each independently a hydrogen atom,
It represents an alkyl group, an aryl group or a halogen atom. A) a compound having at least two vinyl ether groups E in the molecule, or a compound having at least one vinyl ether group E in the molecule, a hydroxyl group, an amino group, and a compound represented by the general formula (III):

[0106]

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(Wherein, R ₃ is each independently a hydrogen atom,
Represents an alkyl group, an aryl group or a halogen atom, and r is 0 or 1. The compound (B1) having at least one reactive group J selected from the alkylene carbonate group G represented by the formula (1) in the molecule.

In the vinyl ether group E represented by the general formula (II), R ₂ is each independently a hydrogen atom, an alkyl group, an aryl group or a halogen atom.
In the alkylene carbonate group G represented by the general formula (III), R ₃ is also each independently a hydrogen atom, an alkyl group, an aryl group, or a halogen atom.

The alkyl group preferably has 1 to 6 carbon atoms, and specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group and a hexyl group. . When the alkyl group has 3 or more carbon atoms, the alkyl group may be linear or branched. The aryl group preferably has 6 to 14 carbon atoms, and specific examples thereof include a phenyl group, a naphthyl group, and a biphenyl group. Further, the halogen atom is preferably a chlorine atom, a bromine atom or an iodine atom.

The alkyl group may be substituted with a halogen atom such as a chlorine atom, a bromine atom or an iodine atom, and the aryl group has 1 to 6 carbon atoms as described above.
May be substituted with an alkyl group or a halogen atom.

However, in the present invention, the vinyl ether group E represented by the general formula (II) is preferably one in which all of R ₂ are hydrogen atoms. Similarly, the group G represented by the general formula (III) is also a group G in which all of R ₃ are hydrogen atoms and p is 0, that is, the following formula (XXIII)

[0112]

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The group G 'is preferably represented by the following formula:

According to the present invention, the vinyl ether compound (B1) is preferably at least one selected from the following first vinyl ether (B1a), second vinyl ether (B1b) and third vinyl ether (B1c). Is a seed.

According to the present invention, the first vinyl ether compound (B1a) has the general formula (XI)

[0116]

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(Wherein R ₁₁ represents an a-valent hydrocarbon group;
E represents the vinyl ether group, and a is an integer of 2 or more. ).

In the first vinyl ether compound (B1a) represented by the general formula (XI), R ₁₁ is an a-valent hydrocarbon group, wherein the hydrocarbon group is a hydrocarbon group. If so, it is not particularly limited, and may be any of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, or a combination thereof. It may be a hydrocarbon group.

However, preferably, a is 2 or 3, particularly preferably 2, and therefore R ₁₁ is preferably a divalent or trivalent hydrocarbon group, particularly preferably 2 And most preferably a divalent aliphatic or alicyclic aliphatic hydrocarbon group.

Preferred specific examples of such a divalent aliphatic or alicyclic aliphatic hydrocarbon group include alkylene groups having 2 to 12 carbon atoms such as ethylene group, propylene group, trimethylene group, and tetramethylene group. And an alicyclic aliphatic hydrocarbon group such as a cyclohexanedimethanol residue.

Accordingly, preferred specific examples of the first vinyl ether compound (B1a) include, for example, butanediol divinyl ether, cyclohexane dimethanol divinyl ether and the like.

According to the present invention, the second vinyl ether compound (B1b) has the general formula (XII)

[0123]

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(Wherein E represents the vinyl ether group, R ₁₂ independently represents a hydrogen atom, an alkyl group, an aryl group or a halogen atom, and Q represents a hydrogen atom or a compound represented by the general formula (XIII)

[0125]

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(Wherein, R ₁₃ is each independently a hydrogen atom,
It represents an alkyl group, an aryl group or a halogen atom. ), And b is an integer from 1 to 10. ).

In the second vinyl ether compound (B1b) represented by the general formula (XII), E represents the vinyl ether group, and R ₁₂ each independently represents a hydrogen atom, an alkyl group, an aryl group or a halogen atom. , Q is a hydrogen atom or a general formula (XIII)

[0128]

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(Wherein, R ₁₃ is each independently a hydrogen atom,
It represents an alkyl group, an aryl group or a halogen atom. ), And b is an integer from 1 to 10.

The alkyl group preferably has 1 to 6 carbon atoms, and specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group and a hexyl group. . When the alkyl group has 3 or more carbon atoms, the alkyl group may be linear or branched. The aryl group preferably has 6 to 14 carbon atoms, and specific examples thereof include a phenyl group, a naphthyl group, and a biphenyl group. Further, the halogen atom is preferably a chlorine atom, a bromine atom or an iodine atom.

The alkyl group may be substituted with a halogen atom such as a chlorine atom, a bromine atom or an iodine atom, and the aryl group has 1 to 6 carbon atoms as described above.
May be substituted with an alkyl group or a halogen atom.

Particularly, in the present invention, b is preferably 2 or 3, and both R ₁₂ and R ₁₃ are preferably all hydrogen atoms.

Therefore, the second compound represented by the general formula (XII)
Specific examples of the vinyl ether compound (B1b) include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, and diethylene glycol monovinyl ether.

According to the present invention, the third vinyl ether compound (B1c) has the general formula (XIV)

[0135]

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(Wherein R ₁₄ represents a (c + d) valent hydrocarbon group, E is the vinyl ether group, J is a hydroxyl group, an amino group and a compound represented by the general formula (III)

[0137]

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(Wherein R ₃ is independently a hydrogen atom,
Represents an alkyl group, an aryl group or a halogen atom, and r is 0 or 1. ) Represents at least one reactive group selected from the alkylene carbonate groups G, and c and d are each an integer of 1 or more. ) Is a compound (B1c).

The hydrocarbon group R ₁₄ is not particularly limited as long as it is a group consisting of a hydrocarbon, and may be an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, or any of these. Any combination may be used, and a saturated hydrocarbon group or an unsaturated hydrocarbon group may be used.

However, in the present invention, c + d is preferably 2 or 3, and particularly preferably c and d.
Are both 1. That is, c + d = 2. Thus, according to the invention, R ₁₄ is preferably divalent or trivalent
A divalent hydrocarbon group, particularly preferably a divalent hydrocarbon group, and most preferably a divalent aliphatic or alicyclic aliphatic hydrocarbon group.

Preferred examples of such a divalent aliphatic or alicyclic aliphatic hydrocarbon group include alkylene having 2 to 12 carbon atoms such as an ethylene group, a propylene group, a trimethylene group and a tetramethylene group. And an alicyclic aliphatic hydrocarbon group such as a cyclohexanedimethanol residue.

Accordingly, preferred specific examples of the third vinyl ether compound (B1c) include, for example, hydroxybutyl vinyl ether, cyclohexane dimethanol monovinyl ether, and a compound represented by the chemical formula (XXIV).

[0143]

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And propenyl ether propylene carbonate represented by the following formula:

According to the present invention, the first, second, and third
May be used alone or as a combination of two or more as the vinyl ether compound (B1) as the second component of the crosslinking agent. (Hydroxyethylamide compound in the second component) In the crosslinking agent according to the present invention, the hydroxyethylamide compound (B2), which is one of the second components, has the general formula (IV)

[0146]

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(Wherein R ₄ independently represents a hydrogen atom or a methyl group). This is a compound having at least two hydroxyethylamide groups K in the molecule.

According to the present invention, such a hydroxyethylamide compound is preferably (B2a) a compound of the general formula (XV)

[0149]

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(Wherein, R ₁₅ represents a (t + u) -valent aromatic hydrocarbon group, R ₁₆ each independently represents a hydrogen atom or a methyl group, and t and u are 0 ≦ t ≦ 2, 2 ≦ u ≦ 4,2
It is an integer satisfying ≦ t + u ≦ 6. A) a first hydroxyethylamide compound (B2a);
b) General formula (XVI)

[0151]

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(Wherein, R ₁₇ represents a (v) having 0 to 20 carbon atoms.
+ W) a valent aliphatic hydrocarbon group, R ₁₈ each independently represents a hydrogen atom or a methyl group, and v and w are 0 ≦ v
≦ 4, 2 ≦ w ≦ 6, 2 ≦ v + w ≦ 10. However, when R ₁₇ is a (v + w) -valent aliphatic hydrocarbon group having 0 carbon atoms, the compound represented by the general formula (XVI) is represented by the general formula (XVIa)

[0153]

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(In the formula, R ₁₈ is the same as the above.) (B2b ′) )), At least one selected from the second compounds (B2b).

In the first hydroxyethylamide compound (B2a) represented by the general formula (XV), R ₁₅ is a (t + u) -valent aromatic hydrocarbon group. Preferred specific examples of such an aromatic hydrocarbon group include a benzene nucleus,
Examples thereof include (t + u) -valent aromatic hydrocarbon groups derived from a naphthalene nucleus or a biphenyl nucleus. According to the invention, preferably t = 0, u is 2, 3 or 4, and R ₁₆ is preferably both hydrogen atoms.

Accordingly, the aromatic hydrocarbon group is a group derived from an aromatic (oxy) polycarboxylic acid which may have one or two hydroxyl groups in the molecule, and is preferably It is a group derived from an aromatic polycarboxylic acid having 2 to 4 carboxyl groups therein.

Specific examples of the group derived from the aromatic polycarboxylic acid having 2 to 4 carboxyl groups in the molecule include, for example, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid, Pyromellitic acid, naphthalene-2,3-dicarboxylic acid, naphthalene-1,
Examples include aromatic hydrocarbon groups derived from 8-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, and the like.

Such a first hydroxyethylamide compound (B1a) can be produced, for example, by the general formula (XXV)

[0159]

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(Wherein R ₁₅ , t and u are as defined above.) The aromatic (oxy) carboxylic acid represented by the general formula (XXVI)

[0161]

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(Wherein, R ₁₆ is the same as defined above).

As described above, R ₁₆ is preferably a hydrogen atom. Therefore, aminoethanol (ethanolamine) is preferably used as the alkanolamine.

Accordingly, preferred specific examples of such a first hydroxyethylamide compound include, for example, terephthalic acid (bishydroxyethylamide).

Similarly, the second compound represented by the above general formula (XVI)
In the hydroxyethylamide compound (B2b),
R ₁₇ is a (v + w) -valent aliphatic hydrocarbon group having 0 to 20 carbon atoms. As a preferable specific example of such a hydrocarbon group, the number of carbon atoms (the number of carbon atoms of the hydrocarbon group) is 2 to 2.
And 12 polyvalent aliphatic hydrocarbon groups derived from aliphatic (oxy) dibasic acids. That is, preferably, v = 0 and w = 2. R ₁₄ is preferably a hydrogen atom.

Therefore, as the aliphatic hydrocarbon group, a hydrocarbon group derived from an aliphatic dibasic acid such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, etc. And hydrocarbon groups derived from aliphatic oxydibasic acids such as malic acid, citric acid and tartaric acid.

In the present invention, when R ₁₇ is a (v + w) -valent aliphatic hydrocarbon group having 0 carbon atoms, as described above, the compound represented by the general formula (XVI) is represented by the general formula (XVI): XVIa)

[0168]

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(Wherein R ₁₈ is as defined above), that is, the compound (B2b ′), that is, bis (hydroxyethylamide) oxalate.

Such a second hydroxyethylamide compound can be prepared, for example, by the general formula (XXVII)

[0171]

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(Wherein R ₁₇ , v and w are the same as defined above) to the aliphatic (oxy) carboxylic acid represented by the general formula (XXVIII)

[0173]

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(Wherein R ₁₈ each independently represents a hydrogen atom or a methyl group). As mentioned above, R ₁₈ is preferably a hydrogen atom.

However, when R ₁₇ is a (v + w) -valent aliphatic hydrocarbon group having 0 carbon atoms, the above formula (XXVII)
It is assumed that the aliphatic (oxy) carboxylic acid represented by I) is oxalic acid.

Accordingly, preferred specific examples of such a second hydroxyethylamide compound include, for example, adipic acid (bishydroxyethylamide). (Oxazoline Compound in Second Component) In the crosslinking agent according to the present invention, the oxazoline compound (B3), which is one of the second components, is represented by the formula (V3):

[0177]

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(Wherein R ₅ independently represents a hydrogen atom or a methyl group.)
Is an oxazoline compound having at least two in the molecule.

According to the present invention, such an oxazoline compound is preferably represented by the formula (B3a):

[0180]

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(Wherein, R ₁₅ represents an aromatic hydrocarbon group of (t + u) valence, R ₁₆ independently represents a hydrogen atom or a methyl group, and t and u represent 0 ≦ t ≦ 2, 2 ≦ u ≦ 4,2
It is an integer satisfying ≦ t + u ≦ 6. (B3a) represented by the general formula (XVIII):

[0182]

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(Wherein R ₁₇ is a group of (v) having 0 to 20 carbon atoms.
+ W) a valent aliphatic hydrocarbon group, R ₁₈ each independently represents a hydrogen atom or a methyl group, and v and w are 0 ≦ v
≦ 4, 2 ≦ w ≦ 6, 2 ≦ v + w ≦ 10. However, when R ₁₇ is a (v + w) -valent aliphatic hydrocarbon group having 0 carbon atoms, the compound represented by the general formula (XVIII) is represented by the general formula (XVIIIa)

[0184]

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(In the formula, R ₁₈ is the same as described above.) It is assumed that the compound is a bisoxazoline compound (B3b ′). ) And at least one selected from the group consisting of (B3b).

The first and second oxazoline compounds are respectively the first hydroxy compound (B2
It can be easily obtained by heating a) and the second hydroxy compound (B2b) to effect cyclization dehydration.

Thus, R ₁₅ , R ₁₆ , R ₁₇ , R ₁₈ , t,
u, v and w are all the same as in the hydroxyethylamide compound, and thus, for example, cyclizing and dehydrating terephthalic acid (bishydroxyethylamide) converts p-phenylene (bis-2-oxazoline). Can be obtained by cyclodehydration of adipic acid (bishydroxyethylamide) to give 1,4
-Butane (bis-2-oxazoline) can be obtained. (Production of Water Absorbing Agent by Crosslinking Water Absorbent Resin) As described above, the crosslinking agent according to the present invention comprises the first component comprising the halohydrin compound (A), the vinyl ether compound (B1) and the hydroxyethylamide compound ( B2)
And at least one second component (B) selected from the oxazoline compound (B3).

Specifically, the halohydrin compound (A)
A first component consisting of a halohydrin compound (A1
a) at least one first halohydrin compound selected from (A1b) and (A1c), or the second halohydrin compound (A2), or the first halohydrin compound and the second halohydrin compound. A mixture is used. According to the present invention, a mixture of a first halohydrin compound and a second halohydrin compound is preferably used as the first component.

As for the second component, the vinyl ether compound (B1), the hydroxyethylamide compound (B2) and the oxazoline compound (B3) are used alone or as a mixture of two or more.

According to the present invention, such a crosslinking agent depends on the type of the water-absorbent resin particles to be treated and the degree of cross-linking possessed by the water-absorbent resin particles. The first component is generally in the range of 0.001 to 20 parts by weight, preferably 0.01 to 15 parts by weight, most preferably 0.1 to 10 parts by weight, and
20 parts by weight, preferably from 0.01 to 15 parts by weight, most preferably from 0.1 to 10 parts by weight of the second component are used in combination.

Particularly preferably, the first component and the second component are added in a total amount of 0.001 to 20 parts by weight, preferably 0.1 to 20 parts by weight.
It is used in the range of from 01 to 15 parts by weight, most preferably in the range of from 0.1 to 10 parts by weight. Here, the weight ratio of the first component / the second component is not particularly limited, but is usually 99 parts by weight. / 1
１／1/99, preferably 75/25 to 2
It is in the range of 5/75.

When the amount of the crosslinking agent used is less than 0.001 part by weight with respect to 100 parts by weight of the water-absorbing resin particles, crosslinking of the water-absorbing resin particles cannot be carried out effectively. When the amount exceeds the part, the crosslinking density becomes too high, and the resulting water-absorbing agent is inferior in both water-absorbing ability and water-absorbing speed.

The surface-crosslinking of the water-absorbent resin particles using the crosslinking agent according to the present invention to obtain a water-absorbing agent is preferably carried out in the presence of water, a hydrophilic organic solvent or a solvent mixture thereof. Specifically, it is preferable to dissolve the above-mentioned crosslinking agent in the above-mentioned solvent, mix the obtained solution with the water-absorbent resin particles, and then heat the obtained mixture.
Examples of the hydrophilic organic solvent include lower aliphatic alcohols such as methanol, ethanol, n-propyl alcohol, and isopropyl alcohol; ketones such as acetone; ethers such as dioxane, tetrahydrofuran, and methoxy (poly) ethylene glycol; Examples include amides such as ε-caprolactam and N, N-dimethylformamide.

The amount of the solvent depends on the type, particle size, water content and the like of the water-absorbing resin particles, but is usually 0.1 to 100 parts by weight of the solid content of the water-absorbing resin particles. It is in the range of 20 parts by weight, preferably in the range of 0.5 to 10 parts by weight.

According to the present invention, a conventionally known surface crosslinking agent such as a polyhydric alcohol compound, an epoxy compound, a polyhydric alcohol compound, or the like, as long as the surface crosslinking of the water-absorbent resin by the crosslinking agent according to the present invention is not prevented. Trivalent amine compound,
Polyisocyanate compound, polyvalent oxazoline compound,
Alkylene carbonate compounds, haloepoxy compounds,
You may use together a silane coupling agent, a polyvalent metal compound, etc.

More specifically, examples of polyhydric alcohol compounds include ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, 1,3-propanediol, dipropylene glycol, 2,2 , 4-Trimethyl-1,3-pentanediol, polypropylene glycol, glycerin, polyglycerin, 2-butene-1,4-diol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol ,
1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,2-cyclohexanol, trimethylolpropane, diethanolamine, triethanolamine,
Examples thereof include polyoxypropylene, oxyethylene-oxypropylene block copolymer, pentaerythritol, sorbitol and the like.

Examples of the epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, propylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether. And glycidol.

Specific examples of the polyvalent amine compound include, for example, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and polyethyleneimine. Inorganic salts and organic salts of these polyamine compounds (for example, aztinium salts and the like) can also be used as a crosslinking agent.

Further, specific examples of the polyisocyanate compound include, for example, 2,4-tolylene diisocyanate,
Hexamethylene diisocyanate and the like can be mentioned, and specific examples of the polyvalent oxazoline compound include, for example,
1,2-ethylenebisoxazoline and the like can be mentioned.

Further, specific examples of the alkylene carbonate include, for example, 1,3-dioxolan-2-one,
Methyl-1,3-dioxolan-2-one, 4,5-dimethyl-1,3-dioxolan-2-one, 4,4-dimethyl-
1,3-dioxolan-2-one, 4-ethyl-1,3-dioxolan-2-one, 4-hydroxymethyl-1,3-
Dioxolan-2-one, 1,3-dioxan-2-one, 4-methyl-1,3-dioxan-2-one, 4,6-
Dimethyl-1,3-dioxan-2-one and the like can be mentioned.

Specific examples of the haloepoxy compound include epichlorohydrin, epibromohydrin, α-methylepichlorohydrin and the like and polyvalent amine adducts thereof (for example, Kaimen (registered trademark) manufactured by Hercules) and the like. Can be mentioned.

In addition to these, silane coupling agents such as γ-glycidoxypropyltrimethoxysilane and γ-aminopropyltriethoxysilane, and hydroxides and chlorides such as zinc, calcium, magnesium, aluminum, iron, and zirconium. A polyvalent metal compound such as a product can also be used as a crosslinking agent.

In order to mix the water-absorbing resin particles with the crosslinking agent, for example, an aqueous solution of the crosslinking agent is sprayed on the water-absorbing resin particles, and then, a cylindrical mixer, a V-shaped mixer, a ribbon mixer,
What is necessary is just to mix using a screw type mixer, a double arm type mixer, a pulverization type kneader, etc. If necessary, the water-absorbing resin particles and the crosslinking agent may be mixed in the presence of a surfactant.
However, the method and means for mixing the water-absorbent resin particles and the crosslinking agent are not limited to the above.

According to the present invention, after mixing the water-absorbent resin particles with the crosslinking agent, the resulting mixture is usually heated to a temperature in the range of 40 to 250 ° C. The surface of the particles can be crosslinked. When the heating temperature is lower than 40 ° C., the surface of the water-absorbent resin particles is not uniformly cross-linked. Therefore, for example, a water-absorbing agent having a good balance between the water-absorption capacity under normal pressure and the water-absorption capacity under pressure is used. I can't get it. However, when the heating temperature is higher than 250 ° C., the water-absorbing resin particles are deteriorated, and the water absorbing performance of the resin may be reduced.

However, since the crosslinking agent according to the present invention has high reactivity, the surface crosslinking reaction of the water-absorbent resin particles can be rapidly and uniformly performed at a relatively low temperature. That is, according to the present invention, the heating temperature is 60 to 2
A range of 00 ° C is preferred, and a range of 70 to 200 ° C is particularly preferred.

The water-absorbing agent obtained by subjecting the water-absorbent resin particles to surface cross-linking according to the present invention is excellent in both water-absorbing ability and water-absorbing speed, and is suitable for use in sanitary articles such as disposable diapers and sanitary napkins. It can be suitably used as an absorbent.

As mentioned above, the crosslinker according to the invention comprises
Using water-absorbent resin particles as a starting material, cross-linking the surface,
Although it can be suitably used for obtaining a water absorbing agent, according to the present invention, a water absorbing agent can also be obtained by using the above-mentioned cross-linking agent as an internal cross-linking agent.

That is, in order to obtain a water-absorbing agent using the cross-linking agent of the present invention as an internal cross-linking agent, it is preferable that acrylic acid and / or a salt thereof (neutralization salt) be used as a main component in the presence of the cross-linking agent. The hydrophilic monomer is polymerized to generate a water-absorbent resin from the hydrophilic monomer, and the water-absorbent resin is cross-linked by the cross-linking agent. Also, as another method, after polymerization of the hydrophilic monomer, or or after polymerization and neutralization, by adding a crosslinking agent to the obtained water-absorbent resin, by crosslinking the water-absorbent resin, A water absorbing agent can be obtained. Usually, the latter method is preferred.

As described above, when the cross-linking agent according to the present invention is used as an internal cross-linking agent, the acrylic acid salt may be an alkali metal salt or an ammonium salt of acrylic acid.
Examples thereof include amine salts and the like. Usually, such an acrylate is used in a range of 90 to 60 mol% based on 10 to 40 mol% of acrylic acid.

The hydrophilic monomer other than acrylic acid or its salt (neutralized salt) is not particularly limited, but
Specifically, for example, methacrylic acid, maleic acid, vinylsulfonic acid, styrenesulfonic acid, 2- (meth) acrylamido-2-methylpropanesulfonic acid, 2- (meth) acryloylethanesulfonic acid, 2- (meth) Anionic unsaturated monomers such as acryloylpropanesulfonic acid and salts thereof, acrylamide, methacrylamide, N
-Ethyl (meth) acrylamide, Nn-propyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, 2-
Nonionic hydrophilic group-containing unsaturated compounds such as hydroxypropyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, polyethylene glycol mono (meth) acrylate, vinylpyridine, N-vinylpyrrolidone, N-acryloylpiperidine, and N-acryloylpyrrolidine. Monomer, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide And cationic unsaturated monomers such as quaternary salts thereof.

When such a monomer other than acrylic acid and its salt is used, the monomer other than acrylic acid and its salt is added to the total amount of acrylic acid and its salt used as the main component. , Usually 30 mol% or less, preferably
It is used in a proportion of 10 mol% or less.

The polymerization of the hydrophilic monomer may be bulk polymerization or precipitation polymerization, but is preferably performed by aqueous solution polymerization or reverse phase suspension polymerization from the viewpoint of performance and easy control of polymerization.

In the polymerization of the above hydrophilic monomer, the polymerization initiator is usually potassium persulfate, ammonium persulfate, sodium persulfate, t-butyl hydroperoxide, hydrogen peroxide, 2,2′-azobis ( A radical polymerization initiator such as 2-aminodipropane) dihydrochloride is used. Furthermore, in order to promote the decomposition of these polymerization initiators into radicals, a redox initiator may be used in combination with a crosslinking agent. Examples of the reducing agent include (bis) sulfite (salt) such as sodium sulfite and sodium bisulfite, L-ascorbic acid (salt), reducing metals (salt) such as ferrous salt, and amines. However, the present invention is not limited to these.

The polymerization of the hydrophilic monomer may be started by irradiating the reaction system with an active energy ray such as radiation, an electron beam, or an ultraviolet ray.

The reaction temperature in the above polymerization reaction is, in particular,
Although not limited, it is usually in the range of 20 to 90 ° C. The reaction time is also not particularly limited, and may be appropriately set according to the type of the hydrophilic monomer or the polymerization initiator, the reaction temperature, and the like.

When a water-absorbing resin is obtained by polymerization of a hydrophilic monomer as described above, and this is cross-linked using the cross-linking agent according to the present invention as an internal cross-linking agent, a water-absorbing resin is obtained.
Conventionally known internal crosslinking agents may be used in combination. Such conventionally known internal crosslinking agents include, for example, N, N-methylenebis (meth) acrylamide,
(Poly) ethylene glycol (meth) acrylate,
(Poly) propylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerin tri (meth) acrylate, glycerin acrylate methacrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, pentaerythritol hexa (meth) acrylate , Triallyl cyanurate, triallyl isocyanurate, triallyl phosphate, triallylamine, poly (meth) allyloxyalkane, (poly) ethylene glycol diglycidyl ether, glycerol diglycidyl ether, ethylene glycol, polyethylene glycol,
Examples thereof include propylene glycol, glycerin, pentaerythritol, ethylenediamine, ethylene carbonate, propylene carbonate, polyethyleneimine, and glycidyl (meth) acrylate.

When the cross-linking agent according to the present invention is used as an internal cross-linking agent, the amount of the cross-linking agent is usually 0.1% with respect to 100 parts by weight of the hydrophilic monomer (ie, water-absorbing resin).
001 to 20 parts by weight, preferably 0.01 to 15 parts by weight, most preferably 0.1 to 10 parts by weight of the first component, and 0.001 to 20 parts by weight, preferably 0.01. ~ 1
5 parts by weight, most preferably in the range from 0.1 to 10 parts by weight of the second component are used in combination.

Particularly preferably, the total amount of the first component and the second component is 0.001 to 20 parts by weight, preferably 0.1 to 20 parts by weight.
It is used in the range of from 01 to 15 parts by weight, most preferably in the range of from 0.1 to 10 parts by weight. Here, the weight ratio of the first component / the second component is not particularly limited, but is usually 99 parts by weight. / 1
１／1/99, preferably 75/25 to 2
It is in the range of 5/75.

When the amount of the crosslinking agent used is less than 0.001 part by weight with respect to 100 parts by weight of the water-absorbing resin particles, crosslinking of the water-absorbing resin particles cannot be carried out effectively. When the amount exceeds the part, the crosslinking density becomes too high, and the resulting water-absorbing agent is inferior in both water-absorbing ability and water-absorbing speed.

When the water-absorbing agent thus obtained is in the form of a gel, it is dried and then, if necessary, pulverized.

[0221]

EXAMPLES The present invention will be described below with reference to Examples together with Production Examples of water-absorbing resin particles and a crosslinking agent, but the present invention is not limited to these Examples. In the following, “part” indicates “part by weight” and “%” indicates “% by weight”. The water absorption capacity under pressure of the water absorbing agent according to the present invention was evaluated as follows.

(Water Absorption Ratio under Pressure of Water Absorbing Agent) A plastic tube (inner diameter 30 mm, height 60 mm) is set upright, and 250 mesh nylon gauze is stuck on the bottom to make a container, and 1 g of the water absorbing agent is put in the container. The weight was uniformly placed, and a weight having an outer diameter of 30 mm was placed on the water absorbing agent so as to have a load of 40 g / cm ² . Next, 60 mL of physiological saline (concentration 0.9%)
The plastic tube containing the water-absorbing agent was immersed in a petri dish (diameter: 12 cm) with the bottom facing down for 30 minutes, pulled up, drained for 15 minutes, and the weight increase of the plastic tube was measured. The water absorption capacity under pressure (g (increase in weight of water-absorbent resin particles) / g (weight of initial water-absorbent resin particles)).

Reference Example 1 (Production of Water Absorbent Resin Particles) After charging 40 g of acrylic acid into a 500 mL separable flask equipped with a stirrer, a reflux condenser and a nitrogen gas introducing tube, water was added thereto while stirring and cooling. 53 g to 17.9% sodium hydroxide 17.9
An aqueous solution in which g was dissolved was added dropwise to neutralize. Nitrogen gas was blown into the obtained aqueous solution for 30 minutes to replace the inside of the flask with nitrogen.

Next, nitrogen blowing 1 was performed in advance.
0.4% aqueous solution of ammonium persulfate and 0.5% N, N'-
0.2 g of an aqueous solution of methylenebisacrylamide was added, and the mixture was sufficiently stirred. After stopping the stirring, the flask was immersed in a hot water bath at 60 ° C. to start the polymerization. After 10 minutes, the temperature reached a maximum temperature of 80 ° C., after which the internal temperature dropped to 60 ° C.
After holding at this temperature for another hour, cool to room temperature,
The polymerization was terminated.

The contents are taken out of the separable flask,
After crushing into small pieces and drying at 105 ° C. for 2 hours, the mixture was crushed using a crusher and sieved, and the material passed through the 60 mesh was collected as water-absorbent resin particles used below.

Production Example 1 (Production of Crosslinking Agent (A1a)) 182 g of sorbitol was placed in a 1-L separable flask.
(1.0 mol), 500 g of toluene, 1.8 g of boron trifluoride ether complex as a catalyst, heating and stirring, 277.5 g of epichlorohydrin (3. 0 mol) was added dropwise. After completion of the dropwise addition, the mixture was further stirred for 2 hours at the same temperature as above, and the disappearance of epichlorohydrin was confirmed based on the quantitative determination of the epoxy group by titration, and the reaction was terminated. After completion of the reaction, toluene was distilled off under reduced pressure. As a reaction product, in the above general formula (VI), R ₆ was a sorbitol residue, X was a chlorine atom, and k = 3 and m = 3. Was obtained as crosslinking agent A1a.

The amount of chlorine (the amount of chlorine in the chlorohydrin group) in the above reaction product was quantitatively analyzed. As a result, it was 21.9% (theoretical amount: 23.0%), and the yield was 95%.

Production Example 2 (Production of Crosslinking Agent (A1b)) Diethylene glycol 1 was placed in a 1 L separable flask.
06 g (1.0 mol) and 0.1 g of a boron trifluoride etherate complex as a catalyst were heated and stirred.
While maintaining the temperature at ℃, 185 g (2.0 mol) of epichlorohydrin was added dropwise. After completion of the dropwise addition, the mixture was further stirred at the same temperature for 2 hours at the same temperature as described above. After confirming disappearance of epichlorohydrin based on the quantification of the epoxy group by titration, the reaction was terminated, and the reaction was terminated. VII) The crosslinking agent A1b wherein R ₇ is a hydrogen atom and n = 2
I got

The amount of chlorine (the amount of chlorine in the chlorohydrin group) in the above reaction product was quantitatively analyzed. As a result, it was 23.2% (theoretical amount: 24.4%), and the yield was 95%.

Production Example 3 (Production of Crosslinking Agent (A1c)) 166 g of diglycerin was placed in a 1-L separable flask.
(1.0 mol), boron trifluoride etherate complex as catalyst
0.9 g was added, and the mixture was heated and stirred, and while keeping the internal temperature at 50 to 70 ° C., 277.5 g of epichlorohydrin (3.0 g) was added thereto.
Mol) was added dropwise. After completion of the dropwise addition, the mixture was further stirred for 2 hours at the same temperature as above, and the disappearance of epichlorohydrin was confirmed based on the quantitative determination of the epoxy group by titration, and the reaction was terminated. As a reaction product, in the compound of the formula (VIII), p = 1, one of the groups R ₈ is a hydrogen atom, and the remaining three are a 3-chloro-2-hydroxypropyl group. A crosslinking agent (A1c) was obtained.

The amount of chlorine (the amount of chlorine in the chlorohydrin group) in the above reaction product was quantitatively analyzed. As a result, it was 23.3% (theoretical amount: 24.0%), and the yield was 97%.

Production Example 4 (Production of Crosslinking Agent (A2)) In a 1 L separable flask, 116 g (1.0 mol) of N, N, N ', N'-tetramethyl-1,2-diaminoethane and water 2
After cooling the internal temperature to 30 ° C. or less, 203 g (2.0 mol) of concentrated hydrochloric acid was slowly added dropwise, and p
H was adjusted to 5-7. While maintaining the internal temperature at 35 to 45 ° C., 185 g (2.0 mol) of epichlorohydrin was dropped into the aqueous solution in about 1 hour, and after completion of the dropping, the mixture was stirred at the same temperature for 2 hours and the epoxy group was titrated. The disappearance of epichlorohydrin was confirmed based on the quantification, and the reaction was terminated. As a reaction product, in the general formula (IX), A was an ethylene group, X was a chlorine atom, and R ₉
Are methyl groups, and the crosslinking agent (a
2) was obtained.

Quantitative analysis of the chlorine content (chlorine content of the chlorohydrin group) in the above reaction product revealed that it was 19.5% (theoretical amount: 20.1%) and the yield was 97%.

Production Example 5 (Production of Crosslinking Agent (B2a)) Dimethyl terephthalate 1 was placed in a 1-L separable flask.
94 g (1.0 mol), 300 g of methanol and 200 g of toluene were charged, and 140 g (2.3 mol) of aminoethanol was added dropwise thereto while keeping the internal temperature at 30 ° C. or lower. After completion of the dropwise addition, the internal temperature was heated to 50 to 80 ° C., and the reaction was performed for 1 hour. After completion of the reaction, the obtained reaction mixture was cooled to room temperature to precipitate crystals. The crystals are collected by filtration,
After drying, in the general formula (XV), t = 0 and u =
2, a hydroxyethylamide compound (b2b) wherein R ₁₅ is a divalent aromatic hydrocarbon group derived from terephthalic acid (that is, a p-phenylene group), and R ₁₆ is a hydrogen atom, 191 g of bis (hydroxyethylamide) terephthalate were obtained.

Production Example 6 (Production of Crosslinking Agent (B2b)) In a 1 L separable flask, aminoethanol 122.
0 g (2.0 mol) and 740 g of water,
118.0 g of dimethyl adipate while maintaining the temperature below ℃
(1.0 mol) was added dropwise. After completion of the dropwise addition, the internal temperature was heated to 70 ° C., and the reaction was performed at 70 ° C. for 1 hour. After completion of the reaction, water and methanol are distilled off under reduced pressure, whereby in the general formula (XVI), v = 0 and w = 2, and R ₁₇ is a divalent aliphatic hydrocarbon derived from adipic acid. Groups (ie, 1,
Hydroxyethylamide compound (B2b) wherein R ₁₈ is a hydrogen atom, that is, an aqueous solution of bis (hydroxyethylamide) adipate 69
0 g (20% solids) were obtained.

Production Example 7 (Production of Crosslinking Agent (b3b)) 200 g of the aqueous solution of bis (hydroxyethylamide) adipate and 500 g of xylene obtained in Production Example 6 were charged into a 1 L separable flask, and the internal temperature was raised to 150 ° C. Then, the mixture was stirred at this temperature for 12 hours, and the formed water was distilled off, whereby bis (hydroxyethylamide) adipate was dehydrated and cyclized. After completion of the reaction, xylene was distilled off under reduced pressure. In the general formula (XVIII), R ₁₇ was a divalent aliphatic hydrocarbon group derived from adipic acid (that is, a 1,4-butylene group). , R ₁₈ are each a hydrogen atom, and v =
An oxazoline compound (b3b) in which 0 and w = 2, that is, 1,4-butylenebis (2-oxazoline) was obtained.

Comparative Example 1 50 g of the water-absorbing resin particles obtained in Reference Example 1 were charged into a double-arm kneader reactor, and the crosslinking agent (A1a) 0.0 was added under stirring.
An aqueous solution in which 6 g was dissolved in water was sprayed and thoroughly mixed. The water-absorbent resin particles treated in this manner are treated at 175 ° C. with 3
Heating was performed for 0 minutes to obtain a water absorbing agent. Table 1 shows the performance of the water absorbing agent thus obtained.

Comparative Examples 2 to 7 In Comparative Example 1, instead of the crosslinking agent (A1a), the crosslinking agents (A1b), (A1c) and (A2), the crosslinking agent triethylene glycol divinyl ether (B1b), B
0.06 g of each of 2a), (B2b) or (B3b)
A water-absorbing agent was obtained in the same manner as in Comparative Example 1 except that was used. Table 1 shows the performance of the water absorbing agent thus obtained.

Comparative Example 8 Comparative Example 1 was repeated except that in place of the crosslinking agent (A1a), 0.06 g of ethylene glycol diglycidyl ether (EX-810 manufactured by Nagase Kasei Kogyo KK) (d) was used. A water absorbing agent was obtained in the same manner as in Example 1. Table 1 shows the performance of the water absorbing agent thus obtained.

Example 1 50 g of the water-absorbent resin particles obtained in Reference Example 1 was charged into a double-arm kneader, and the first component (A) of the crosslinking agent was stirred under stirring.
An aqueous solution obtained by dissolving 0.03 g of 1a) and 0.03 g of the second component triethylene glycol divinyl ether (B1b) in water was sprayed and mixed well. The water-absorbing resin particles thus treated were heated at 175 ° C. for 30 minutes to obtain a water-absorbing agent according to the present invention. Table 1 shows the performance of the water absorbing agent thus obtained.

Examples 2 to 10 In Example 1, the first component (A1a) and / or
Alternatively, instead of the second component triethylene glycol divinyl ether (B1b), the first component 0.03 as shown in Table 1 is used.
g and / or 0.03 g of the second component, respectively, to obtain a water-absorbing agent according to the present invention in the same manner as in Example 1. Table 1 shows the performance of the water absorbing agent thus obtained.

Examples 11 to 13 As the first component of the crosslinking agent, 1 / (A1c) / (A2)
0.03 g of the mixture at 1% by weight and 0.03 g of the second component shown in Table 1
A water-absorbing agent according to the present invention was obtained in the same manner as in Example 1, except that g was used. Table 1 shows the performance of the water absorbing agent thus obtained.

[0243]

[Table 1]

[0244]

As described above, the crosslinking agent for the water-absorbing resin according to the present invention comprises a first component comprising a halohydrin compound (A), a vinyl ether compound (B1), a hydroxyethylamide compound (B2) and an oxazoline. A second compound comprising at least one compound selected from the group consisting of compound (B3) and
Combined with the components, each component has no epoxy group in the molecule, so it is excellent in safety, and effectively cross-links water-absorbent resin particles at low temperature. Can be. The crosslinking agent according to the present invention can also be used as an internal crosslinking agent to obtain a water absorbing agent.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C07C 43/13 C07C 233/18 4J100 215/40 233/69 233/18 C07D 263/14 233/69 A61F 13/18 307A C07D 263/14 (72) Inventor Tetsuya Hosomi 236 Nakai, Tatsuno-cho, Tatsuno, Hyogo Prefecture Inside Nagase ChemteX Corporation (72) Inventor Nobuaki Aoki 236 Nakai, Tatsuno-cho, Tatsuno-shi, Hyogo Nagase ChemteX Corporation F term (for reference) 4C003 AA23 4C056 AA01 AB01 AC02 AD01 AE02 BA08 BB01 BC01 4C098 AA09 CC02 DD05 DD23 4H006 AA03 AB48 4J002 BC101 BG001 BG071 BG131 BH001 BQ001 ED017 ED046 EH007 EL107 EG001A00 00 007 AL62Q AL66Q AM15Q AM21Q AN01Q AP01Q BA03Q BA05Q BA28Q BA56Q BC65Q BC68Q CA01 CA04 CA05 C A31 DA37 HA53 HC04 HC12 HC13 HC38 HC48 HC63 JA50 JA57 JA59 JA60 JA64 JA67

Claims (14)

[Claims] (A) General formula (I) (Wherein, X represents a chlorine atom or a bromine atom, and R ₁ represents a hydrogen atom or an alkyl group.) A first component comprising a halohydrin compound having at least two halohydrin groups D represented by the following formula: (B) (B1) General formula (II) (Wherein R ₂ is independently a hydrogen atom, an alkyl group,
Indicates an aryl group or a halogen atom. Or a vinyl ether compound having at least two vinyl ether groups E in the molecule, or a hydroxyl group, an amino group and a general formula (III) (Wherein, R ₃ is each independently a hydrogen atom, an alkyl group,
Represents an aryl group or a halogen atom, and r is 0 or 1. A) a vinyl ether compound (B1) having at least one reactive group J selected from an alkylene carbonate group G represented by the following formula (B1):
2) General formula (IV) (Wherein R ₄ each independently represents a hydrogen atom or a methyl group.) A hydroxyethylamide compound (B2) having at least two hydroxyethylamide groups K in the molecule represented by the following general formula (B3): (V) (Wherein, R ₅ each independently represents a hydrogen atom or a methyl group) and at least one selected from oxazoline compounds (B3) having at least two 2-oxazolyl groups L in the molecule. A water-absorbing resin crosslinking agent comprising the second component. 2. The halohydrin compound is represented by the general formula (VI): (Wherein, R ₆ represents a (k + m) -valent aliphatic hydrocarbon group having 2 to 10 carbon atoms, X represents a chlorine atom or a bromine atom,
k and m are 2 ≦ k ≦ 6, 0 ≦ m ≦ 4, 2 ≦ k + m ≦ 6
Is an integer that satisfies (A1a)
And (A1b) a compound represented by the general formula (VII): (Wherein, R ₇ represents a hydrogen atom or a methyl group, X represents a chlorine atom or a bromine atom, and n is an integer of 1 to 50), and (A1c) Formula (VIII) (Wherein, R ₈ represents a hydrogen atom or a 3-halo-2-hydroxypropyl group, and at least two of R ₈ are 3-
A halo-2-hydroxypropyl group, p is 1 to 10
Is an integer. 2. The water-absorbent resin crosslinking agent according to claim 1, which is at least one member selected from the group consisting of: 3. The halohydrin compound is represented by the general formula (I)
X) (Wherein, A is an alkylene group having 2 to 8 carbon atoms or a general formula (X) (Wherein, R ₁₀ represents a hydrocarbon group having 1 to 4 carbon atoms, and s is an integer of 1 to 3).
₉ each independently represents a hydrocarbon group having 1 to 4 carbon atoms,
X represents a chlorine atom or a bromine atom, and q is an integer of 0-5. A quaternary ammonium group and 3
The water-absorbing tree crosslinking agent according to claim 1, which is a compound (A2) having two or more -halo-2-hydroxypropyl groups. 4. A halohydrin compound represented by the general formula (VI): (Wherein, R ₆ represents a (k + m) -valent aliphatic hydrocarbon group having 2 to 10 carbon atoms, X represents a chlorine atom or a bromine atom,
k and m are 2 ≦ k ≦ 6, 0 ≦ m ≦ 4, 2 ≦ k + m ≦ 6
Is an integer that satisfies (A1a)
And (A1b) a compound represented by the general formula (VII): (Wherein, R ₇ represents a hydrogen atom or a methyl group, X represents a chlorine atom or a bromine atom, and n is an integer of 1 to 50), and (A1c) Formula (VIII) (Wherein, R ₈ represents a hydrogen atom or a 3-halo-2-hydroxypropyl group, and at least two of R ₈ are 3-
A halo-2-hydroxypropyl group, p is 1 to 10
Is an integer. (A1c) and (A2) a compound represented by the general formula (IX): (Wherein, A is an alkylene group having 2 to 8 carbon atoms or a general formula (X) (Wherein, R ₁₀ represents a hydrocarbon group having 1 to 4 carbon atoms, and s is an integer of 1 to 3).
₉ each independently represents a hydrocarbon group having 1 to 4 carbon atoms,
X represents a chlorine atom or a bromine atom, and q is an integer of 0-5. A quaternary ammonium group and 3
The water-absorbing tree crosslinking agent according to claim 1, comprising a compound (A2) having two or more halo-2-hydroxypropyl groups. 5. A halohydrin compound comprising at least one compound selected from the group consisting of a compound (A1a), a compound (A1b) and a compound (A1c) in an amount of 10 to 90% by weight and a compound (A2) 90 to 90% by weight.
The water-absorbing tree crosslinking agent according to claim 4, which comprises 10% by weight. 6. A vinyl ether compound (B1) having the general formula (XI): (Wherein E is the vinyl ether group, R ₁₁ is an a-valent hydrocarbon group, and a is an integer of 2 or more), and is a compound (B1a) represented by the formula (1). Water absorbent resin crosslinking agent. 7. A vinyl ether compound (B1) having the general formula (XII): (In the formula, E represents the vinyl ether group, R ₁₂ independently represents a hydrogen atom, an alkyl group, an aryl group or a halogen atom, and Q represents a hydrogen atom or a general formula (XIII). (Wherein, R ₁₃ is each independently a hydrogen atom, an alkyl group,
Indicates an aryl group or a halogen atom. )), And b is an integer from 1 to 10. The water-absorbing resin crosslinking agent according to claim 1, which is a compound (B1b) represented by the formula: 8. A vinyl ether compound (B1) having the general formula (XIV): (Wherein, R ₁₄ represents a (c + d) -valent hydrocarbon group, E is the vinyl ether group, J is a hydroxyl group, an amino group, and a compound represented by the general formula (III). (Wherein, R ₃ is each independently a hydrogen atom, an alkyl group,
Represents an aryl group or a halogen atom, and r is 0 or 1. ) Represents at least one reactive group selected from the alkylene carbonate groups G, and c and d are each an integer of 1 or more. (B1)
The water-absorbent resin crosslinking agent according to claim 1, which is c). 9. A compound of the formula (XV) wherein the hydroxyethylamide compound (B2) is (B2a) (Wherein, R ₁₅ represents a (t + u) -valent aromatic hydrocarbon group, R ₁₆ each independently represents a hydrogen atom or a methyl group, and t and u are 0 ≦ t ≦ 2, 2 ≦ u ≦ 4 , 2 ≦ t + u
It is an integer satisfying ≦ 6. (B2)
a) and (B2b) a general formula (XVI) (Wherein, R ₁₇ represents a (v + w) -valent aliphatic hydrocarbon group having 0 to 20 carbon atoms, R ₁₈ independently represents a hydrogen atom or a methyl group, and v and w are 0 ≦ v ≦ 4, 2 ≦ w
It is an integer satisfying ≦ 6, 2 ≦ v + w ≦ 10. Where R
_{When 17} is a (v + w) -valent aliphatic hydrocarbon group having 0 carbon atoms, the compound represented by the general formula (XVI) is represented by the general formula (XVIa): (In the formula, R ₁₈ is the same as described above.) (B2)
The water-absorbing tree crosslinking agent according to claim 1, which is at least one member selected from b). 10. An oxazoline compound (B3) comprising (B3
a) General formula (XVII) (Wherein, R ₁₅ represents a (t + u) -valent aromatic hydrocarbon group, R ₁₆ each independently represents a hydrogen atom or a methyl group, and t and u are 0 ≦ t ≦ 2, 2 ≦ u ≦ 4 , 2 ≦ t + u
It is an integer satisfying ≦ 6. (B3)
a) and (B3b) a compound represented by the general formula (XVIII): (Wherein, R ₁₇ represents a (v + w) -valent aliphatic hydrocarbon group having 0 to 20 carbon atoms, R ₁₈ independently represents a hydrogen atom or a methyl group, and v and w are 0 ≦ v ≦ 4, 2 ≦ w
It is an integer satisfying ≦ 6, 2 ≦ v + w ≦ 10. Where R
_{When 17} is a (v + w) -valent aliphatic hydrocarbon group having 0 carbon atoms, the compound represented by the general formula (XVIII) is a compound represented by the general formula (XVIIIa) (In the formula, R ₁₈ is the same as described above.) It is assumed that the compound is a bisoxazoline compound (B3b ′). The water-absorbing tree crosslinking agent according to claim 1, which is at least one member selected from the group consisting of a compound (B3b) represented by 11. A cross-linking agent for a water-absorbent resin for surface cross-linking according to claim 1. 12. The method according to claim 1, wherein 100 parts by weight of the water-absorbent resin having a carboxylic acid group and / or a carboxylic acid salt group is added to 100 parts by weight.
A water-absorbing agent obtained by adding 0.001 to 20 parts by weight of the water-absorbing resin cross-linking agent according to any one of the above, heating and crosslinking. 13. The method according to claim 1, wherein 100 parts by weight of the water-absorbent resin having a carboxylic acid group and / or a carboxylic acid salt group is added to 100 parts by weight.
A method for producing a water-absorbing agent, comprising adding 0.001 to 20 parts by weight of a water-absorbing resin crosslinking agent according to any one of the above, and heating and crosslinking. 14. The surface cross-linking agent according to any one of claims 1 to 11, wherein 100 parts by weight of the water-absorbent resin particles (A) having a carboxylic acid group and / or a carboxylate group are added to the surface crosslinking agent.
A surface-crosslinked water-absorbing resin obtained by adding 0 parts by weight and heating.