JPH111559A - Production of crosslinked polyaspartic acid-based resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To industrially advantageously obtain the subject biodegradable resin, having excellent water absorptivity, and useful for paper diapers, agriculture/ horticulture, etc., by reacting polysuccinimide in a dispersed state with a crosslinking agent followed by hydrolyzing the imide ring. SOLUTION: For example, polysuccinimide >=30,000 in molecular weight is dissolved in a good solvent (N,N-dimethylformamide) as an organic solvent capable of substantially completely dissolving polysuccinimide followed by adding to the above solution a poor solvent (e.g. water, methanol) selected from the group consisting of water and organic solvents incapable of substantially completely dissolving polysuccimide to set the polysuccinimide in a dispersed state; subsequently, pref. 0.1-50 wt.% of the polysuccinimide in the above state is reacted with a crosslinking agent (pref. a polyamide, polythiol, e.g. hydrazine) at 0-200 deg.C followed by hydrolyzing the imide ring, thus obtaining the objective resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a crosslinked polyaspartic acid-based resin having (bio) degradability and high water absorption.

[0002]

[Prior art]

[Technical background of water-absorbent resin] A water-absorbent resin is a resin that can absorb tens to thousands of times as much water as its own weight.
Sanitary articles such as disposable diapers, breast milk pads, disposable rags, dressing materials for wound protection, medical underpads, medical supplies such as cataplasms, pet sheets, portable toilets, gel fragrances, gel deodorants, and sweat-absorbing fibers , Household goods such as disposable body warmers, shampoos, gels for setting, toiletries such as moisturizers, water retention materials for agriculture and horticulture, life-extending agents for cut flowers, floral foam (fixing material for cut flowers), nursery for nursery, water Agricultural and horticultural products such as cultivation, vegetation sheet, seed tape, fluid sowing, dew condensation prevention agricultural sheet, freshness retaining material for food tray, food wrapping material such as drip absorbent sheet, cold insulator, fresh vegetable transportation Materials for transportation such as water-absorbent sheets, building materials for preventing dew condensation, sealing materials for civil engineering and construction, sludge preventing agents for shield method, concrete admixtures,
Materials for civil engineering and construction such as gaskets and packing, sealing materials for electronic devices such as optical fibers, waterproof materials for communication cables, materials for electric devices such as ink jet recording paper, coagulants for sludge, dehydration of gasoline and oils, and water removal. It is used in a wide range of fields such as water treatment agents such as agents, printing pastes, water-swellable toys, and artificial snow.

[0003] Further, by utilizing the sustained-release properties of the chemicals, it is expected to be used in applications such as sustained-release fertilizers, sustained-release pesticides, and sustained-release drugs. Further, it is also expected to be used as a humidity control material utilizing its hydrophilicity, and as an antistatic agent utilizing its charge retention.

[Prior art relating to water-absorbing resin] Examples of the water-absorbing resin used in such applications include, for example,
Crosslinked polyacrylic acid partially neutralized product (JP-A-55-8430)
No. 4, U.S. Pat. No. 4,625,001), a partially hydrolyzed starch-acrylonitrile copolymer (JP-A-46-439).
No. 95), a starch-acrylic acid graft copolymer (JP-A-51-125468), and a hydrolyzate of a vinyl acetate-acrylate copolymer (JP-A-52-14689).
No.), copolymerized crosslinked product of 2-acrylamido-2-methylpropanesulfonic acid and acrylic acid (European patent 00681)
No. 89), a crosslinked polymer of a cationic monomer (US Pat. No. 4,906,717), a hydrolyzate of a crosslinked isobutylene-maleic anhydride copolymer (US Pat. No. 4,389,513)
Etc. are known.

However, since these water-absorbent resins do not have decomposability, disposal after use is a problem.

At present, these water-absorbent resins are incinerated at the time of disposal and landfilled. However, in the incinerator method, damage to furnace materials due to heat generated during incineration is not considered. In addition, it is pointed out that it causes global warming and acid rain. In addition, waste such as disposable diapers using a water-absorbent resin is difficult to burn because it contains a large amount of water, and it is suspected that it causes dioxin generation which is easily generated at 800 ° C. or lower to lower the temperature of the incinerator. ing.

On the other hand, in the landfill method, the plastic has a problem that the volume is bulky, the ground does not stabilize because it does not rot, and there is a big problem that the place suitable for the landfill has disappeared.

That is, these resins are poorly decomposable and exist semipermanently in water and soil, which is a very serious problem in view of environmental conservation in waste treatment. For example, in the case of disposable resins represented by sanitary materials such as disposable diapers and sanitary articles, recycling the resin requires a great deal of cost, and the amount of incineration is large, so that the burden on the global environment is great. When a crosslinked polyacrylic acid resin is used as a water retention material for agriculture and horticulture, Ca ²⁺
It is reported that the complex forms a complex with polyvalent ions such as those described above to form an insoluble layer (Matsumoto et al., Polymer, 42
Vol., August issue, 1993). Although such layers are said to have low toxicity per se, they are not present in nature at all, and the effects on ecosystems of accumulation of these resins in soil for a long time are unknown. Need to be examined, and its use requires a careful attitude. Similarly, in the case of a nonionic resin, a complex is not formed, but the nondecomposable resin may accumulate in soil due to its nondegradability, and its effect on the natural world is doubtful.

Further, these polymerization resins use monomers that are highly toxic to human skin and the like, and many studies have been made to remove them from products after polymerization. Is difficult to remove. In particular, it is expected to be more difficult in production on an industrial scale.

[Technical background of water-absorbing resin having biodegradability] On the other hand, in recent years, biodegradable polymers have attracted attention as "earth-friendly materials", and it has been proposed to use this as a water-absorbing resin. ing.

Examples of the biodegradable water-absorbing resin used in such applications include cross-linked products of polyethylene oxide (Japanese Patent Application Laid-Open No. 6-157795), cross-linked products of polyvinyl alcohol and cross-linked products of carboxymethyl cellulose (US Pat. No. 4650716), crosslinked alginic acid,
Crosslinked starch, crosslinked polyamino acid and the like are known.
Among these, crosslinked polyethylene oxide and crosslinked polyvinyl alcohol have low water absorption, and are not suitable especially when used as materials for products requiring high water absorption such as sanitary products, disposable diapers, disposable rags, and paper towels.

[0012] Further, since these compounds can be biodegraded only by special bacteria, biodegradation is slow or not at all under general conditions.
When the molecular weight is further increased, the decomposability extremely decreases.

Crosslinked saccharides such as crosslinked carboxymethylcellulose, crosslinked alginic acid, and crosslinked starch have many strong hydrogen bonds in their molecules, and therefore have strong interactions between molecules and between polymers. The molecular chains cannot be widely opened, and the water absorption capacity is not high.

[Technical background of polyamino acid-based water-absorbing resin] On the other hand, a resin obtained by crosslinking a polyamino acid is biodegradable and thus is friendly to the global environment. It has been shown that it is digested and absorbed, does not show antigenicity in the living body, and that the decomposition products have no toxicity.

As an example of description of such a resin, poly-γ
A method for producing a resin having a high water-absorbing ability by irradiating glutamic acid with γ-rays has been reported (Kunioka et al., Journal of Polymers, Vol. 50, No. 10, p. 755 (1993)). However, from the industrial point of view, ⁶⁰ Co irradiation equipment used in this technique, in order to shut off radioactivity requires large-scale facilities, realistic due to the need for sufficient consideration to the management is not. Another problem is that polyglutamic acid as a starting material is expensive.

Also, a method for obtaining a hydrogel by cross-linking an acidic amino acid has been reported [Akamatsu et al., US Pat. No. 3,948,863 (corresponding to Japanese Patent Publication No. 52-41309), Iwatsuki et al., JP-A-5-279416. ]. Further, it has been reported that a crosslinked amino acid resin is used as a water-absorbing polymer (Sikes et al., JP-A-6-506244; US Pat. Nos. 5,247,068 and 5,284,936; Suzuki et al.
JP-A-7-309943, Harada et al., JP-A-8-598
No. 20).

However, in any of these reports, these resins are not practical because of insufficient water absorption and salt water absorption.

[Background of the technical idea of the present inventors] As described in JP-A-7-224163, the present inventors reacted polysuccinimide with a crosslinking agent to form A technique for producing a crosslinked polyaspartic acid-based resin having a high salt water absorption ability by hydrolysis is disclosed.

The present inventors have disclosed in Japanese Patent Application Laid-Open No. 9-1698.
As described in No. 40, after cross-linking the polysuccinimide, the remaining imide ring is hydrolyzed in a uniform mixed solvent of a water-miscible organic solvent and water, whereby the cross-linking with high salt water absorption capacity is performed. A technique for producing a polyaspartic acid-based resin has been disclosed.

The crosslinked polyaspartic acid resins obtained by these techniques are very useful because they are earth-friendly and have high water absorption. However, from an industrial point of view, there was room for further improvement.

That is, in these methods, unless the production process of the crosslinked polysuccinimide is sufficiently controlled, the crosslinking does not proceed sufficiently, and a water-absorbing resin having high water-absorbing ability may not be obtained. In addition, when the crosslinking reaction proceeds sufficiently, the resin during the crosslinking reaction contains the reaction solvent and the entire reaction system is solidified, so that the treatment during the stirring becomes difficult, and the treatment after the reaction is extremely difficult. So it was not a suitable method for industrial production. Therefore, in the method for producing a crosslinked polysuccinimide which is a precursor of a crosslinked polyaspartic acid-based resin, there is room for improvement in terms of process control, simplification of the process, and improvement.

[0022]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a crosslinked polyaspartic acid-based resin which solves the above-mentioned conventional problems and has biodegradability and excellent water absorption. An object of the present invention is to provide a method which can be manufactured by a simple process.

[0023]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, completed the present invention.

That is, the present invention is specified by the following items [1] to [14]. [1] A method for producing a crosslinked polyaspartic acid-based resin, comprising subjecting a polysuccinimide in a dispersed state with a dispersant to a crosslinking reaction with a crosslinking agent to hydrolyze an imide ring. [2] The crosslinking agent is a polyamine [1]
3. The method for producing a crosslinked polyaspartic acid-based resin described in 1. above. [3] The method for producing a crosslinked polyaspartic acid-based resin according to [1] or [2], wherein the dispersant is a water-miscible organic solvent. [4] The method for producing a crosslinked polyaspartic acid-based resin according to [1] or [2], wherein the dispersant is a water-immiscible organic solvent. [5] The cross-linking described in [1] or [2], wherein the dispersant is a poor solvent selected from the group consisting of an organic solvent and water that cannot substantially completely dissolve the polysuccinimide. A method for producing a polyaspartic acid-based resin. [6] dissolving the polysuccinimide in a good solvent which is an organic solvent capable of substantially completely dissolving the polysuccinimide,
Polysuccinimide is dispersed by adding a poor solvent selected from the group consisting of an organic solvent and water that cannot substantially completely dissolve the polysuccinimide, and reacting the dispersed polysuccinimide with a crosslinking agent. The method for producing a crosslinked polyaspartic acid-based resin according to any one of [1] to [5]. [7] A mixed solvent of a good solvent that is an organic solvent capable of substantially completely dissolving polysuccinimide, and a poor solvent selected from the group consisting of an organic solvent that cannot substantially completely dissolve polysuccinimide and water. Characterized in that polysuccinimide is dispersed therein and reacted with a crosslinking agent [1]
The method for producing a crosslinked polyaspartic acid-based resin according to any one of claims 1 to 5. [8] dissolving the polysuccinimide in a good solvent which is an organic solvent capable of substantially completely dissolving the polysuccinimide,
After the addition of the crosslinking agent, a poor solvent selected from the group consisting of an organic solvent and water, which cannot substantially completely dissolve the polysuccinimide, is added and dispersed, and reacted with the crosslinking agent [ The method for producing a crosslinked polyaspartic acid-based resin according to any one of [1] to [5]. [9] A solution obtained by dissolving polysuccinimide in a good solvent which is an organic solvent capable of substantially completely dissolving polysuccinimide and adding a cross-linking agent to an organic solvent in which polysuccinimide cannot be substantially completely dissolved The method for producing a crosslinked polyaspartic acid-based resin according to any one of [1] to [5], wherein the resin is dispersed in a poor solvent selected from the group consisting of water and water and reacted with a crosslinking agent. [10] The “dispersed state” of polysuccinimide is a solid / liquid dispersion of a solid phase containing polysuccinimide and a liquid phase containing a dispersant [1] to [9]. The method for producing the crosslinked polyaspartic acid-based resin described in any of the above. [11] “Solid phase containing polysuccinimide”
Characterized by mixing a good solvent containing a polysuccinimide and a poor solvent miscible with the good solvent, as described in [10]. Method of manufacturing resin. [12] The “dispersion state” of polysuccinimide is a liquid / liquid dispersion of a liquid phase obtained by dissolving polysuccinimide in a good solvent and a liquid phase containing a dispersant [1] to [1]. [9] The method for producing a crosslinked polyaspartic acid-based resin described in any of [9]. [13] “Liquid / liquid dispersion” means that when a liquid phase obtained by dissolving polysuccinimide in a good solvent and a poor solvent immiscible with the good solvent are mixed, the two liquids are dissolved. [12] The method for producing a crosslinked polyaspartic acid-based resin as described in [12], wherein the resin is developed by not performing the process. [14] A crosslinked polyaspartic acid-based resin produced by the production method according to any one of [1] to [13].

According to the present invention, if the polysuccinimide is crosslinked in a dispersed state and the remaining imide ring is hydrolyzed, the process control for avoiding excessive gelling can be omitted, and the crosslinking reaction proceeds favorably. Therefore, a crosslinked polysuccinimide can be produced with a high productivity by a simple process, and when it is hydrolyzed, a crosslinked polyaspartic resin having (bio) degradability and high water absorption can be produced.

The crosslinked polyaspartic acid-based resin obtained according to the present invention is biodegradable after disposal and is therefore environmentally friendly.
It is very useful as a superabsorbent resin having excellent water absorbing ability.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

[1] Structure of Crosslinked Polyaspartic Acid Resin The crosslinked polyaspartic acid resin produced in the present invention can be broadly divided into structural parts based on the main chain basic skeleton part, side chain part and crosslinked part. Become. Hereinafter, these are referred to as 3
This will be described separately.

[1-1] Structure of Main Chain Basic Skeleton of Crosslinked Polyaspartic Acid Resin The repeating unit of the main chain basic skeleton of the crosslinked polyaspartic acid resin produced in the present invention is composed of an aspartic acid residue alone. It may be a copolymer of aspartic acid and an amino acid other than aspartic acid. In the present invention, the repeating unit composed of aspartic acid in the polymer is referred to as "polyaspartic acid residue" regardless of the type of bonding.

Specific examples of amino acids other than aspartic acid include, for example, 19 kinds of essential amino acids except aspartic acid, L-ornithine, a series of α-amino acids, and β-amino acids.
Amino acids and amino acids such as alanine, γ-aminobutyric acid, neutral amino acids, acidic amino acids, ω-esters of acidic amino acids, basic amino acids, N-substituted basic amino acids, aspartic acid-L-phenylalanine dimer (aspartame) Derivatives, aminosulfonic acids such as L-cysteic acid and the like can be mentioned. The α-amino acid may be an optically active form (L-form, D-form) or a racemic form.

When it is a copolymer, it may be a block copolymer or a random copolymer. Also, it may be a graft.

The number of repeating units comprising a polyaspartic acid residue is not particularly limited, but is preferably from 1 to 99.8% with respect to the total number of repeating units constituting the molecule.
10 to 99.8% is more preferable.

The repeating unit of the main chain basic skeleton of the crosslinked polyaspartic acid resin is composed of a polyaspartic acid residue alone or a copolymer with glutamic acid or lysine because of its high water absorbing ability. From the viewpoint of industrial production, the repeating unit is particularly preferably composed of a polyaspartic acid residue alone.

In the basic skeleton of the main chain of the polyaspartic resin, the amide bond in the main chain may be an α bond or a β bond. That is, in the case of polyaspartic acid and its copolymer, when the amino group of aspartic acid or a copolymer unit and the carboxyl group at the α-position of aspartic acid are bonded, the α-bond is formed, and the β-position of aspartic acid is Is a β bond when bonded to a carboxyl group. In the case of this polyaspartic acid, the α bond and the β bond usually exist in a mixed state. In the present invention, the binding mode is not particularly limited.

The side chain group and the crosslinking group of the polymer of the present invention are
Basically, it is a carboxylic acid derivative in which the carboxyl group of polyaspartic acid is substituted. The details will be described below. [1-2] Structure of Side Chain of Crosslinked Polyaspartic Acid Resin The side chain of the crosslinked polyaspartic acid resin has a structure in which the imide ring of the crosslinked polysuccinimide is opened by hydrolysis. Contains the generated carboxyl group. Further, the crosslinked polyaspartic acid-based resin may include a side chain having another substituent. Other substituents are not particularly limited, for example, a hydroxyl group, an amino group,
Pendant groups containing at least one mercapto group, carboxyl group, sulfonic acid group, phosphonic acid group, alkyl group, aryl group, aralkyl group and the like can be mentioned. Further, the pendant group may be an alkyl group, aralkyl group, or aryl group having no specific substituent. These pendant groups are connected to the polyaspartic acid residue by an amide bond, an ester bond, a thioester bond, or the like.

The carboxyl group generated by the hydrolysis may be free or form a salt. Specific examples of the ion forming a salt include, for example, sodium,
Ions such as potassium and lithium; alkali metal ions,
Ammonium; tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, tetrapentylammonium, tetrahexylammonium, ethyltrimethylammonium, trimethylpropylammonium, butyltrimethylammonium, pentyltrimethylammonium,
Ammonium ions such as hexyltrimethylammonium, cyclohexyltrimethylammonium, benzyltrimethylammonium, triethylpropylammonium, triethylbutylammonium, triethylpentylammonium, triethylhexylammonium, cyclohexyltriethylammonium, benzyltriethylammonium ion; trimethylamine, triethylamine, tripropylamine, tripropylamine Butylamine, tripentylamine, trihexylamine, triethanolamine, tripropanolamine, tributanolamine, tripentanolamine, trihexanolamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dicycloamine Hexylamine, di-benzylamine, ethylmethylamine, methylpropylamine, butyl methylamine, methyl pentyl amine, methyl hexyl amine, methyl amine, ethylamine, propylamine, butylamine, pentylamine, hexylamine,
Examples thereof include amine ions such as octylamine, decylamine, dodecylamine, and hexadecylamine ions.

Among these, the higher the atomic weight or molecular weight of the ion, the higher the molecular weight per monomer unit and the smaller the water absorption per unit weight. When there is a possibility of touching human skin or the like, it is preferable that irritation to the skin or the like be low. From these points, it is preferable to use sodium, potassium, lithium, ammonium and triethanolamine, and it is particularly preferable to use sodium and potassium from the viewpoint of cost.

[1-3] Structure of Crosslinked Portion of Crosslinked Polyaspartic Acid Resin The molecular structure of the crosslinked portion in the crosslinked polyaspartic acid resin is not particularly limited. The crosslinked portion of the crosslinked polyaspartic acid-based resin can be understood as a “bonding portion” with the polymer main chain basic skeleton and a “connecting portion” bridging them. Hereinafter, these will be described.

[1-3-1] Bonding portion of crosslinked portion of crosslinked polyaspartic acid-based resin The bonding portion of crosslinked portion of crosslinked polyaspartic acid-based resin is not particularly limited. As a specific example, for example,
Examples of the structure include an amide bond, an ester bond, and a thioester bond. These may be used alone,
A plurality of structures may be mixed.

[1-3-2] Linking Portion of Crosslinked Portion of Crosslinked Polyaspartic Acid Resin The connecting portion of crosslinked portion of crosslinked polyaspartic acid resin is not particularly limited. Specific examples of the connecting portion are described below.

-CH_Two-, -CH_TwoCH_Two-, -CH_TwoCH
_TwoCH_Two-, -CH_TwoCH_TwoCH_TwoCH_Two-,-(CH_Two)
_Five-,-(CH_Two)₆-,-(CH_Two)₇-,-(CH_Two)₈
-,-(CH_Two)₉-,-(CH_Two)_Ten-,-(CH_Two)₁₁
-,-(CH_Two)₁₂-,-(CH_Two)₁₃-,-(CH_Two)
₁₄-,-(CH_Two)_Fifteen-,-(CH_Two)₁₆-,-(C
H_Two)₁₇-,-(CH_Two)₁₈-, -CH_TwoCH_TwoOCH_TwoC
H_Two-,-(CH_TwoCH_TwoO)_TwoCH _TwoCH_Two-,-(CH_Two
CH_TwoO)_ThreeCH_TwoCH_Two-,-(CH_TwoCH_TwoO)_FourCH_TwoC
H_Two-,-(CH_TwoCH_TwoO)_FiveCH_TwoCH_Two-,-(CH_Two
CH_TwoO)₆CH_TwoCH_Two-, -CH_TwoCH_TwoCH_TwoOCH_TwoC
H_TwoCH_Two-,-(CH_TwoCH_TwoCH_TwoO)_TwoCH_TwoCH_TwoCH
_Two-,-(CH_TwoCH_TwoCH_TwoO)_ThreeCH_TwoCH_TwoCH_Two−, −
(CH_TwoCH_TwoCH_TwoO)_FourCH_TwoCH_TwoCH_Two-,-(CH_Two
CH_TwoCH_TwoO)_FiveCH_TwoCH_TwoCH_Two-,-(CH_TwoCH_TwoC
H_TwoO)₆CH_TwoCH_TwoCH_Two−,

[0042]

Embedded image

[0043]

Embedded image These linking moieties may be unsubstituted or substituted with a substituent. Examples of this substituent include an optionally branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an aralkyl group, an optionally substituted phenyl group, and an optionally substituted phenyl group. A good naphthyl group, an optionally branched alkoxy group having 1 to 18 carbon atoms, an aralkyloxy group, a phenylthio group, an optionally branched alkylthio group having 1 to 18 carbon atoms, An alkylamino group which may be branched, a dialkylamino group wherein each alkyl group may have 1 to 18 carbon atoms and an optionally branched trialkyl wherein each alkyl group has 1 to 18 carbon atoms Ammonium group, hydroxyl group, amino group, mercapto group,
Examples include a carboxyl group, a sulfonic acid group, a phosphonic acid group and salts thereof, an alkoxycarbonyl group, an alkylcarbonyloxy group and the like.

For example, alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, cyclopropyl, cyclobutyl, Cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl, aralkyl groups such as benzyl, phenylethyl, phenylpropyl and phenylbutyl, phenyl, tolyl, xylyl,
Chlorophenyl, phenyl group such as biphenyl, naphthyl, naphthyl group such as methylnaphthyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy, Alkoxy groups such as tetradecyloxy, pentadecyloxy, hexadecyloxy, heptyldecyloxy, octyldecyloxy, aralkyloxy groups such as phenoxy, benzyloxy, tolyloxy, methylthio, ethylthio, propylthio, butylthio, pentylthio, hexylthio, heptylthio, Octylthio, nonylthio, decylthio, undecylthio, dodecylthio, tridecylthio, tetradecylthio, pentadecylthio, hexadecylthio Alkylthio groups such as heptyldecylthio and octyldecylthio, phenylthio groups, aralkylthio groups such as benzylthio and tolylthio, methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, heptylamino, octylamino, nonylamino, Decylamino, undecylamino, dodecylamino, tridecylamino,
Alkylamino groups such as tetradecylamino, pentadecylamino, hexadecylamino, heptyldecylamino, octyldecylamino, dimethylamino, diethylamino, dipropylamino, dibutylamino, dipentylamino, dihexylamino, diheptylamino, dioctylamino, Dialkyl such as dinonylamino, didecylamino, diundecylamino, didodecylamino, ditridecylamino, ditetradecylamino, dipentadecylamino, dihexadecylamino, diheptyldecylamino, dioctyldecylamino, ethylmethylamino and methylpropylamino Amino group, trimethylammonium, triethylammonium, tripropylammonium, tributylammonium, tripentylammonium, trihexyl Ammonium, triheptyl ammonium, trioctyl ammonium, trinonyl ammonium, tridecyl ammonium, triundecyl ammonium, tridodecyl ammonium, tritetradecyl ammonium, tripentadecyl ammonium, trihexadecyl ammonium, triheptyl decyl ammonium, trioctyl decyl Ammonium, dimethylethylammonium, dimethylbenzylammonium, trialkylammonium groups such as methyldibenzylammonium, hydroxyl group, amino group, mercapto group, carboxyl group, or sulfonic acid group, or phosphonic acid group, and salts thereof, methyloxycarbonyl , Ethyloxycarbonyl, propyloxycarbonyl, butyloxycarbonyl, pentyloxycarbonyl, Sill oxycarbonyl, heptyloxycarbonyl, octyloxycarbonyl, nonyloxycarbonyl, decyloxycarbonyl, undecyl oxycarbonyl, dodecyloxycarbonyl, tridecyl oxycarbonyl, tetradecyloxy carbonyl, pentadecyloxy carbonyl,
Alkyloxycarbonyl groups such as hexadecyloxycarbonyl, heptadecyloxycarbonyl and octadecyloxycarbonyl, methylcarbonyloxy, ethylcarbonyloxy, propylcarbonyloxy, butylcarbonyloxy, pentylcarbonyloxy, hexylcarbonyloxy, heptylcarbonyloxy, octylcarbonyl Alkyl such as oxy, nonylcarbonyloxy, decylcarbonyloxy, undecylcarbonyloxy, dodecylcarbonyloxy, tridecylcarbonyloxy, tetradecylcarbonyloxy, pentadecylcarbonyloxy, hexadecylcarbonyloxy, heptadecylcarbonyloxy, and octadecylcarbonyloxy Examples thereof include a carbonyloxy group.

When one having a large molecular weight is selected from these, the molecular weight of the crosslinked portion becomes large, the molecular weight per repeating unit becomes relatively large, and the water absorption per unit weight becomes small. It is preferable to select In addition, it is generally preferable to select a simple production method. For example, unsubstituted or substituted (for example, methyl, ethyl, methoxy, methyloxycarbonyl and / or methylcarbonyloxy group; and / or hydroxyl group, amino group, mercapto group, carboxyl group, sulfonic acid group and / or Or a phosphonic acid group and / or a salt thereof).

Further, when a crosslinked polyaspartic acid resin is used for a water retention material, it is preferable that a polar group be present in the resin molecule. Therefore, the crosslinked portion contains an unsubstituted polar group. Or those substituted with a substituent containing a polar group (for example, a hydroxyl group, an amino group, a mercapto group, a carboxyl group, a sulfonic acid group and a phosphonic acid group, and / or a salt thereof).

Here, the amount of the cross-linking portion is not particularly limited, but the number of the repeating units having the cross-linking portion is preferably 0.1 to 20%, and -10% is more preferable.

[2] Method for Producing Polysuccinimide The method for producing the polysuccinimide before crosslinking used in the present invention is not particularly limited. As a specific example, for example, Journal of American Chemical Society (J. Amer. Chem. Soc.)
80, 3361 to (1958).

The molecular weight of the polysuccinimide used is
Although not particularly limited, the higher the molecular weight, the higher the capacity as a water retention material. Generally, it is 30,000 or more, preferably 50,000 or more, more preferably 90,000 or more.

The polysuccinimide may have a linear structure or a branched structure.

[3] Method for Producing Crosslinked Polysuccinimide According to the present invention, by reacting a polysuccinimide dispersed in a dispersant with a crosslinking agent, the crosslinked polysuccinimide can be produced at a high productivity by a simple process. It can be manufactured by The dispersant is preferably a poor solvent selected from the group consisting of an organic solvent and water, which cannot substantially completely dissolve the polysuccinimide.

Poor solvents (eg, water, and / or
Or other poor solvent), the following methods [3-1] to [3-5] can be mentioned as examples of the method of reacting the polysuccinimide in a dispersed state with a crosslinking agent.

[3-1] A method in which polysuccinimide is dispersed in a poor solvent as a dispersant and reacted with a crosslinking agent.

[3-2] A method in which a polysuccinimide is dissolved in a good solvent to prepare a polysuccinimide solution, mixed with a poor solvent as a dispersant to make the polysuccinimide in a dispersed state, and reacted with a crosslinking agent. .

[3-3] A method in which a mixed solution of a good solvent and a poor solvent as a dispersing agent is prepared, and polysuccinimide is added to the mixed solution to form a dispersed state, and reacted with a crosslinking agent. [3-4] A first step in which a polysuccinimide is dissolved in a good solvent to prepare a polysuccinimide solution, a cross-linking agent is added to partially advance the cross-linking reaction, and a polysuccinic acid is used in the first step. Before the imide is gelled by the crosslinking reaction,
A method including a second step in which a polysuccinimide is dispersed by adding a poor solvent as a dispersant, and a crosslinking reaction further proceeds.

[3-5] A method of dissolving polysuccinimide in a good solvent to prepare a polysuccinimide solution, gradually adding a poor solvent as a dispersant to form a dispersed state, and reacting with a crosslinking agent.

Method [3-1] is a method in which polysuccinimide is dispersed in a poor solvent as a dispersant,
The polysuccinimide during the progress of the crosslinking reaction is not dissolved in the solvent and does not swell. On the other hand, the method [3-
2] is different in that polysuccinimide is once dissolved in a good solvent, and then mixed with this polysuccinimide solution and a poor solvent as a dispersant to disperse the polysuccinimide. In this method [3-2], the polysuccinimide during the progress of the crosslinking reaction is in a dispersed state, but is in a state of being dissolved or swollen to some extent by the good solvent.

Accordingly, the method [3-2] is different from the method [3-2]
As compared with [1], the crosslinking reaction easily proceeds uniformly. Also,
Since the polysuccinimide once dissolved becomes finely dispersed by reprecipitation, its dispersion state is also good.

In the method [3-4], once the polysuccinimide gels during the progress of the crosslinking reaction, it becomes difficult to disperse the polysuccinimide with a dispersant. Therefore, it is necessary to add a poor solvent before gelling. It is. Further, before adding the crosslinking agent or after adding the crosslinking agent, an appropriate amount of a poor solvent or an acid may be added for the purpose of delaying the crosslinking reaction and preventing gelation. In the first step and the second step, the imide ring of the crosslinked polysuccinimide can be hydrolyzed.

Specific examples of the poor solvent used in the methods [3-1] to [3-5] will be described later. Especially,
In the methods [3-2] to [3-5], since a good solvent and a poor solvent are used in combination, it is preferable that both solvents have a property of being mutually miscible. In this case, the dispersion state is solid / liquid dispersion.

On the other hand, when the good solvent and the poor solvent do not have the property of being mutually miscible, liquid / liquid dispersion occurs, and the layer containing polysuccinimide becomes a gel as the crosslinking proceeds.

That is, in the present invention, the concept of “dispersion” means that a solid phase containing polysuccinimide, a solution in which polysuccinimide is dissolved, and a gel in which polysuccinimide is crosslinked are all in a dispersed state. Also included.
These phases may or may not contain a cross-linking agent or the like, but the cross-linking reaction proceeds faster when these phases contain a cross-linking agent.

[4] Manufacturing Conditions for Crosslinked Polysuccinimide The manufacturing conditions common to the above-mentioned methods [3-1] to [3-5] will be described below.

[4-1] Good Solvent Used in Crosslinking Reaction The concept of the term "good solvent" used herein includes an organic solvent capable of substantially completely dissolving polysuccinimide.

The good solvent used in the present invention is not particularly limited. Generally, a good solvent that can substantially dissolve the crosslinking agent to be used is more preferable. For example, when a cross-linking agent having high hydrophilicity is used, the polarity of the mixed solvent is preferably higher, and when a cross-linking agent having high hydrophobicity is used, the lower polarity of the mixed solvent is preferable.

Specific examples of the good solvent include, for example, N, N
-Dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, N, N'-dimethylimidazolidinone, dimethylsulfoxide, sulfolane and the like. Among these, N, N-dimethylformamide, in which the solubility of polysuccinimide is high,
N, N-dimethylacetamide is particularly preferred. These solvents may be used alone or in combination of two or more.

[4-2] Poor Solvent Used in Crosslinking Reaction The concept of the term "poor solvent" as used herein includes an organic solvent and water that cannot substantially completely dissolve polysuccinimide. In the present invention, this poor solvent can be suitably used as a dispersant.

The poor solvent used in the present invention is not particularly limited, and any solvent generally used in chemical reactions and having low solubility in polysuccinimide can be used. When a poor solvent and a good solvent are used in combination, the miscibility with the good solvent is not limited. In general, like the good solvent described above, it is generally preferable to use a poor solvent that can substantially dissolve the crosslinking agent used. In particular, when the good solvent cannot dissolve the crosslinking agent, it is effective to use a poor solvent that can dissolve the crosslinking agent.

Specific examples of the poor solvent include water, alcohols such as methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, heptanol, octanol, 2-methoxyethanol and 2-ethoxyethanol, ethylene glycol and diethylene glycol. , Triethylene glycol,
Propylene glycol, glycols such as dipropylene glycol, methyl glycosolve, glycosolves such as ethyl glycosolve, acetone, methyl ethyl ketone,
Ketones such as methyl isobutyl ketone, cyclic ethers such as tetrahydrofuran and dioxane, petroleum ether, pentane, hexane, heptane, octane, cyclohexane, benzene, toluene, ethylbenzene, xylene,
Decalin, diphenyl ether, anisole, cresol and the like. Among these, water, methanol, ethanol, propanol, and isopropanol are particularly preferable, in which the crosslinking agent can be dissolved when the polarity of the crosslinking agent is high.
These solvents may be used alone or in combination of two or more.

These poor solvents can be used not only for the purpose of dispersing the polysuccinimide but also for the purpose of, for example, slowing down the crosslinking reaction.

[4-3] Mixing ratio of good solvent and poor solvent used in the crosslinking reaction When good solvent and poor solvent are used in combination, the mixing ratio is not particularly limited. If the amount of the poor solvent is appropriately increased, the effect of the poor solvent is exhibited, and the polysuccinimide is in a dispersed state, thereby preventing gelation. On the other hand, if the amount of the poor solvent is appropriately reduced, the effect of the good solvent is exhibited, and the dispersion state of the polysuccinimide becomes uniform. Also, usually, if the amount of poor solvent is appropriately reduced,
The cost of solvent recovery is reduced, which is economically advantageous.

As in the case described above, it is generally preferable to use a good solvent or a poor solvent which can substantially dissolve the cross-linking agent to be used when used as a mixed solvent. .

[4-4] Concentration of Polysuccinimide Used in Crosslinking Reaction The concentration of polysuccinimide in the dispersion containing polysuccinimide at the time when the crosslinking reaction proceeds is not particularly limited. It is preferably from 0.1 to 50% by weight, particularly preferably from 1 to 40% by weight.

[4-5] Particle Size of Polysuccinimide Used in Crosslinking Reaction It is preferable that the particle size of the polysuccinimide in the dispersed state is small because the reaction is easy. Here, based on the particle size (average particle diameter) of the polysuccinimide in a dry state, the particle size is preferably 100 μm or less, and 10 μm or less.
μm or less is more preferable. As described above, if the particles of polysuccinimide are appropriately small, the cross-linking reaction easily proceeds to the inside, and when hydrolysis is performed later, the amount of uncross-linked water-soluble portions is small, and the reduction in yield and performance is prevented. it can.

In this regard, in order to suppress the non-uniform cross-linking reaction, it is preferable to adopt a method of positively expressing a more uniform dispersion state of polysuccinimide by wet pulverization. This wet pulverization is particularly effective in the method [3-
1].

In the case of cross-linking using a polysuccinimide which has been dispersed in a dispersant with a dispersant, wet pulverization is preferably carried out by performing the cross-linking reaction while wet pulverization, so as to develop a more uniform dispersion state. here,
The concept of the term "wet milling" includes an embodiment in which an object is ground in water and / or an organic solvent.

In consideration of the transfer and the like, the pulverization operation is performed by a method of pulverization in water and / or an organic solvent, or a method of pulverizing an object to be treated as it is and then transferring the same to a solvent (water and / or organic solvent) for transfer. To impart fluidity.

The solvent used in the wet grinding is not particularly limited, and examples thereof include a poor solvent represented by [4-2] or a mixture of a good solvent of [4-1] and a good solvent of [4-2]. it can.
These solvents may be used alone or as a mixture of two or more.

The pulverizing apparatus to be used is not particularly limited as long as it can substantially pulverize a solid or gel-like substance comprising a polysuccinimide, a cross-linking agent or a cross-linked product of the polysuccinimide. As a specific example,
It is preferable to use a blade with a blade or a type in which a general blade is rotated at high speed. Further, in order to increase the crushing efficiency, a crusher provided with a baffle is also preferable, and a crusher having both a crushing and a transfer function is also preferable. The shape of the stirring blade is not particularly limited, and may be a screw shape, a ribbon shape or a wire shape to which a large load is not easily applied.

For example, pipeline homomixer, homomix line mill, Golator pump, disintegrator, mixer, spike mill, homogenizer, meat chopper, noodle making machine, coffee mill, juicer mixer, vortex mixer, tumbler mixer, etc. Can be

Here, the rotation speed (rpm, rotation speed per minute) of the bladed stirring blade or ordinary stirring blade is not particularly limited as long as the pulverization is substantially achieved. Generally, high speed is preferable as long as the temperature of the system is not heated by frictional heat. Specifically, 10 to 100,000 rpm is preferable, 10 to 50,000 rpm is more preferable, and
10,000 rpm is particularly preferred.

The wet pulverization may be performed in one stage or may be performed in several stages. The particle size (average particle diameter) of the polysuccinimide in a dispersed state during the cross-linking reaction achieved by wet pulverization is not particularly limited, but a smaller one is preferable because the dispersion can be performed in a uniform dispersed state.
0.00001-1 mm is preferable, and 0.00001-
0.1 mm is more preferable. Normally, if the particle size of the dispersion is too large, the reaction becomes non-uniform, resulting in a decrease in yield and the like, and a resin having a high water absorption may not be obtained in some cases.

The pulverized product cross-linked during wet pulverization is then subjected to a hydrolysis reaction of an imide ring. This hydrolysis reaction step usually uses water as an essential component. Therefore, when wet pulverization is performed in water and / or a water-miscible organic solvent, the next hydrolysis step may be performed as it is without separating the pulverized material.

A salt (organic salt and / or inorganic salt) for the hydrolysis reaction is allowed to coexist with the object to be pulverized in advance by dissolving or mixing. Can also be performed. Further, simultaneously with the pulverization, an aqueous alkali solution for the hydrolysis reaction may be added to perform the pulverization and the hydrolysis reaction at the same time.

When a slurry containing a solid is obtained by the pulverization and the solid is separated from the solvent, it is preferable to separate the solid in consideration of solvent recovery and the like. Preferred separation methods include general chemical separation methods such as decantation and centrifugation. The obtained solid may be dried and then subjected to the next hydrolysis step, or may be subjected to the next hydrolysis step while keeping the wet cake. That is, the organic solvent may be removed before the hydrolysis step, or the hydrolysis step may be performed without removing the organic solvent.

[4-6] Types of Crosslinking Agent Used in Crosslinking Reaction The crosslinking agent used in the present invention is not particularly limited as long as it is a polyfunctional compound which reacts with the imide ring of polysuccinimide. For example, polyfunctional compounds such as polyamine and polythiol can be mentioned. Specific examples thereof include hydrazine, ethylenediamine, propylenediamine, 1,4-butanediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine,
Decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tetradecamethylenediamine,
Aliphatic polyamines such as hexadecamethylenediamine, 1-amino-2,2-bis (aminomethyl) butane, tetraaminomethane, diethylenetriamine and triethylenetetramine, norbornenediamine, 1,4-diaminocyclohexane, 1,3,5 One molecule of an alicyclic polyamine such as triaminocyclohexane, isophoronediamine, an aromatic polyamine such as phenylenediamine, tolylenediamine, xylylenediamine, a basic amino acid or an ester thereof, or a monoamino compound such as cystamine or the like; Polyamines such as compounds and derivatives thereof bonded by one or more disulfide bonds, 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 1,6-hexanedithiol, pentane Aliphatic polythiols such as rislithiol, alicyclic polythiols such as cyclohexanedithiol, aromatic polythiols such as xylylenedithiol, benzenedithiol, toluenedithiol, trimethylolpropane tris (thioglycolate), trimethylolpropane tris (3-mercaptopro) Pionate)
Esters such as pentaerythritol tetrakis (thioglycolate) and pentaerythritol tetrakis (3-mercaptopropionate) polythiol. In addition, protein-constituting amino acids typified by lysine, cystine, and ornithine, and salts or esters thereof are also included.

Among the other crosslinking agents, ethylenediamine, propylenediamine, 1,4-butanediamine, heptamethylenediamine, hexamethylenediamine, lysine, ornithine have a low odor and a high reactivity with the imide ring of polysuccinimide. , Cystamine is preferred.

[4-7] Amount of Cross-Linking Agent Used in Cross-Linking Reaction The amount of the cross-linking agent is not particularly limited, and is appropriately determined according to the degree of cross-linking determined by the functional number and molecular weight of the cross-linking agent, and the type of use. do it. Here, the degree of cross-linking is defined to indicate the distance between cross-links, the number of constituent monomer units, or the degree of the ratio of cross-linked portions to the polymer main chain.

In general, if the amount of the crosslinking agent is too large, the degree of crosslinking becomes too high, and the water absorbing ability of the crosslinked polyaspartic acid resin decreases. Conversely, if the amount of the cross-linking agent is too small, the degree of cross-linking will be too low, and eventually a water-soluble, partially cross-linked polyaspartic acid-based resin that does not exhibit water absorption will be obtained. . Therefore,
The amount of the crosslinking agent may be appropriately determined so as to achieve an appropriate degree of crosslinking. The amount of the crosslinking agent is generally 0.1 to 30% based on the total number of the monomer units of the polysuccinimide.
Is particularly preferable, and 1 to 20% is particularly preferable.

[4-8] Catalyst used in crosslinking reaction In the crosslinking reaction, a catalyst may be used if necessary. As the catalyst, a base catalyst is generally used.

Examples of the base catalyst include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide; alkali metal carbonates such as sodium carbonate, potassium carbonate and lithium carbonate; sodium hydrogen carbonate; Inorganic base reagents such as alkali metal bicarbonates such as potassium, alkali metal acetates such as sodium acetate and potassium acetate, alkali metal salts such as sodium oxalate, and ammonia; trimethylamine, triethylamine, tripropylamine, tributylamine, tributylamine Pentylamine, trihexylamine, triethanolamine, tripropanolamine, tributanolamine, tripentanolamine, trihexanolamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentyne Amine, dihexyl amine, dicyclohexylamine, dibenzylamine, ethylmethylamine, methylpropylamine, butyl methylamine, methyl pentyl amine, methyl hexyl amine, methyl amine, ethylamine, propylamine, butylamine,
Organic base reagents such as amines such as pentylamine, hexylamine, octylamine, decylamine, dodecylamine, hexadecylamine, pyridine, picoline, quinoline and the like can be mentioned.

[4-9] Reaction Temperature of Cross-Linking Reaction The reaction temperature of the cross-linking reaction is not particularly limited, and may be appropriately determined in consideration of the reactivity of the cross-linking agent and the dispersion state of polysuccinimide. Generally, it is preferably from 0 to 200C, more preferably from 10 to 80C.

[4-10] Conditions for Liquid / Liquid Dispersion Crosslinking Reaction When a good solvent and a poor solvent for polysuccinimide are not mixed, a solution (good solvent) of polysuccinimide and a dispersant (poor solvent) are mixed. / Liquid separation occurs, and a suitable stirring can be performed to obtain a dispersed state. The concept of “dispersion” in the present invention includes this state, and the crosslinking reaction can proceed in a liquid / liquid dispersion state. When reacting polysuccinimide and a crosslinking agent in a liquid / liquid dispersion state, the layer containing polysuccinimide gels as the crosslinking reaction proceeds. Since the gel has tackiness during the progress of cross-linking, it is desirable to adopt a method in which the dispersed gels do not adhere to each other.

Although the method is not particularly limited,
There are a method of maintaining dispersion at high speed and a method of using a surfactant or the like. Both may be used in combination. The method for maintaining dispersion at high speed is not particularly limited, but the stirring device described in the section of [4-5] can be used.

The surfactant is not particularly limited, and examples thereof include alkyl laurates such as sodium lauryl sulfate, triethanolamine lauryl sulfate and ammonium lauryl sulfate, sodium polyoxyethylene lauryl ether sulfate, and polyoxyethylene lauryl ether trisulfate. Polyoxyethylene alkyl ether sulfate such as ethanolamine, sodium lauryl sulfonate, potassium lauryl sulfonate, triethanolamine lauryl sulfonate, ammonium lauryl sulfonate, alkyl sulfonate such as sodium stearyl sulfonate, dodecyl diphenyl ether disulfonic acid Alkyl diphenyl ether disulfonate such as sodium, alkyl aryl sulfo such as sodium dodecylbenzene sulfonate Acid, sodium dodecylnaphthalenesulfonate, alkylnaphthalenesulfonic acid such as sodium salt of β-naphthalenesulfonic acid formalin condensate, ligninsulfonic acid salt, sodium distearylsulfosuccinate, dialkylsulfosuccinate such as sodium dioctylsulfosuccinate, poly Oxyethylene lauryl ether acetic acid, polyoxyethylene alkyl ether acetates such as sodium polyoxyethylene lauryl ether acetate, alkylene maleic acid copolymers, carboxymethyl cellulose, and carboxymethylated copolymers having carboxyl groups such as polysaccharides Alkali metal salts, coconut oil fatty acids, palmitic acid, behenic acid, lauric acid, stearic acid, myristic acid, oleic acid, sodium laurate, potassium laurate Triethanolamine, ammonium laurate, ammonium laurate, sodium stearate, potassium stearate, fatty acids such as triethanolamine stearate, ammonium stearate or salts thereof, sodium lauryl phosphate, triethanolamine lauryl phosphate, lauryl phosphorus Anionic surfactants such as monoalkyl phosphates such as ammonium acid, lauryl alcohol, myristyl alcohol, cetanol, cetostearyl alcohol, stearyl alcohol, 2-octyldodecanol, higher alcohols such as behenyl alcohol, glycerin, ethylene glycol, Diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol , Polyoxyethylene alkyls such as polyhydric alcohols such as sorbitol, sorbitan, pentaerythritol, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene higher alcohol ether ether,
Polyoxyethylene alkylphenyl ethers such as polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl dodecyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, and polyoxyethylene styryl phenyl ether Polyoxyethylene alkyl esters such as polyethylene glycol monostearate, polyethylene glycol distearate, ethylene glycol distearate, and polyoxyethylene hydrogenated castor oil; and polyoxyethylene glycol and polyoxypropylene glycol such as polyoxyethylene polyoxypropylene glycol. Copolymer, sorbitan monolaurate, sol monostearate Tan, sorbitan monooleate,
Sorbitan monopalmitate, sorbitan sesquioleate, sorbitan coconut oil fatty acid, sorbitan monopalmitate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, etc., sorbitan alkyl esters, polyoxyethylene sorbitan monolaurate, polyoxy Ethylene palm oil fatty acid sorbitan, polyoxyethylene sorbitan monopalmitate,
Polyoxyethylene sorbitan alkyl esters such as polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan triisostearate, and tetraolein Fatty acid polyoxyethylene sorbite such as polyoxyethylene sorbite acid, glycerin alkyl ester such as glycerin monostearate, glyceryl monooleate, glyceryl monocaprylate, propylene glycol alkyl ester such as propylene glycol monostearate, polyoxyethylene stearyl Polyoxyethylene alkylamines such as amines, palm kernel oil fatty acid diethanolamide, Alkyl alkanolamides such as phosphoric acid diethanolamide, nonionic surfactants such as cellulose, starch, and polysaccharides; alkylamine salts such as coconut amine acetate and stearylamine acetate; lauryl trimethyl ammonium chloride; stearyl trimethyl ammonium chloride; cetyl trimethyl chloride Cationic surfactants such as alkyltrimethylammonium salts such as ammonium, distearyldimethylammonium chloride, dialkyldimethylammonium salts such as dialkyl (12-18) dimethylammonium chloride, benzalkonium salts such as benzalkonium chloride, and lauryl betaine , Alkyl betaines such as stearyl betaine, alkyl methines such as betaine lauryl dimethylaminoacetate and betaine stearyl dimethylamino acetate. Arylamino acid betaine, 2-alkyl -N- carboxymethyl -N-
Alkyl carboxymethyl hydroxyethyl imidazolinium betaine, such as alkyl carboxymethyl hydroxy ethyl imidazolinium betaine, amide amide propyl betaine, alkyl amide propyl betaine such as amide amide propyl betaine, alkyl hydroxy sulfo betaine such as lauryl hydroxy sulfo betaine, lauryl dimethylamine And amphoteric surfactants such as alkyldimethylamine oxides such as oxides.

[4-11] Operation after Cross-linking Reaction After the cross-linking reaction is completed, the organic solvent used for the cross-linking reaction may not be separated and the process may proceed directly to the next hydrolysis step. It may be taken out as imide and proceed to the next hydrolysis step.

The separation of the crosslinked polysuccinimide and the organic solvent may be performed according to a generally used method. For example, filtration, decantation, centrifugation and the like can be adopted.

[5] Hydrolysis of imide ring of cross-linked polysuccinimide Hydrolysis of the remaining imide ring of cross-linked polysuccinimide can be easily carried out by the method described in Japanese Patent Application No. 9-68185. That is, the hydrolysis is carried out in a mixed solution of water and a water-miscible organic solvent, in an aqueous solution of an inorganic or organic salt, or in warm water at 40 to 100 ° C., and a plurality of these may be used in combination. Absent.

In the hydrolysis of the imide ring of the crosslinked polysuccinimide, gelation becomes remarkable in water, and stirring becomes difficult. In an organic solvent, precipitates aggregate to make stirring difficult. These methods are used because they become slow or do not proceed sufficiently and the amount of water absorbed by the produced resin decreases.

When a water-miscible organic solvent is used, the organic solvent to be used is not particularly limited. Generally, alcohols such as methanol, ethanol, propanol, isopropanol, butanol, 2-methoxyethanol and 2-ethoxyethanol, Glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol and dipropylene glycol; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; cyclic ethers such as tetrahydrofuran and dioxane; N, N-dimethylformamide;
N, N-dimethylacetamide, N-methylpyrrolidone, N, N'-dimethylimidazolidinone, dimethylsulfoxide, sulfolane and the like. Among them, methanol, ethanol, propanol, isopropanol, and butanol are preferable because they are particularly easy to dry when the crosslinked polyaspartic acid-based resin is dried, and the solvent hardly remains in the composition after drying.

The amount of water used is preferably 1 to 10 times by weight, particularly preferably 1 to 5 times by weight of the water-absorbing resin to be produced, in order to increase the volumetric efficiency.

The ratio of water used is 5 to the mixed solvent.
-100% by weight is preferred, and 20-80% by weight is particularly preferred.

When an inorganic or organic salt is used, the inorganic or organic salt is not particularly limited, and general salts can be widely used. For example, neutral salts, basic salts, and acid salts can be used. Here, in the case of a polyvalent metal salt, the concentration thereof cannot be increased because the polyvalent metal salt is ionically crosslinked with the carboxyl group generated by hydrolysis of the imide ring to increase the degree of crosslinking.

As a method for adding the salt to be used, the salt may be dissolved in water or may be formed by neutralization in water. Further, the salt generated by the crosslinking reaction can be used as it is.

The salts used include hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, sulfuric acid, sulfurous acid, disulfurous acid, amidosulfuric acid, thiosulfuric acid, nitric acid, nitrous acid, phosphoric acid, phosphorous acid,
Orthophosphoric acid, metaphosphoric acid, hypophosphoric acid, pyrophosphoric acid, phosphinic acid, phosphonic acid, carbonic acid, percarbonic acid, boric acid, orthoboric acid, metaboric acid, chloric acid, perchloric acid, hypochlorous acid, bromic acid, perbromine Acid, hypobromite, iodic acid, periodate, hypoiodite, silicic acid, orthosilicic acid, metasilicic acid, aluminate, telluric acid, isocyanic acid, thiocyanic acid, manganic acid, permanganic acid, periodate Inorganic or inorganic mineral acids such as chromic acid, dichromic acid, metaantimonous acid, metavanadic acid, molybdic acid, organic salts of organic phosphonic acids, organic sulfonic acids, organic carboxylic acids, oxalic acids, and organic phenols; Objects and the like. Among these, hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, sulfuric acid, sulfurous acid, which have low irritation to the skin, no redox properties, low cost, and high solubility in water , Nitric acid, nitrous acid, phosphoric acid, orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, phosphinic acid, phosphonic acid, carbonic acid, boric acid, orthoboric acid, metaboric acid, silicic acid, orthosilicic acid, metasilicic acid, oxalic acid, organic phosphonic acid , Organic sulfonic acids,
Metal salts or organic base salts of organic carboxylic acids are preferred, and hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, carbonic acid, boric acid, organic phosphonic acids, organic sulfonic acids, and metal salts or organic base salts of organic carboxylic acids are particularly preferred.

The metal of the metal salt is lithium, sodium, potassium, beryllium, magnesium, aluminum, calcium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, gerium, rubidium, strontium, Yttrium, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, cadmium, indium, tin, tellurium, cesium, barium, cerium, gold, mercury, thallium, lead and the like. Of these, lithium, sodium, and potassium, which have low irritation to the skin and the like, are low in cost, and have high solubility in water, are preferable.

Examples of the organic salt include ammonium, tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, tetrapentylammonium, tetrahexylammonium, ethyltrimethylammonium, trimethylpropylammonium, butyltrimethylammonium, pentyltrimethylammonium, hexyl Ammonium salts such as trimethylammonium, cyclohexyltrimethylammonium, benzyltrimethylammonium, triethylpropylammonium, triethylbutylammonium, triethylpentylammonium, triethylhexylammonium, cyclohexyltriethylammonium, and benzyltriethylammonium; Butylamine, tripropylamine,
Tributylamine, tripentylamine, trihexylamine, triethanolamine, tripropanolamine, tributanolamine, tripentanolamine,
Trihexanolamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dicyclohexylamine,
Dibenzylamine, ethylmethylamine, methylpropylamine, butylmethylamine, methylpentylamine, methylhexylamine, methylamine, ethylamine, propylamine, butylamine, pentylamine,
Examples thereof include amine salts such as hexylamine, octylamine, decylamine, dodecylamine, and hexadecylamine. In consideration of solubility in water, odor, safety, and cost, tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, ethyltrimethylammonium,
Benzyltrimethylammonium, ammonium salts such as benzyltriethylammonium, trimethylamine,
Particularly preferred are amine salts of triethylamine, tripropylamine, tributylamine, triethanolamine, and the like.

Examples of specific salts include sodium chloride, potassium chloride, lithium chloride, ammonium chloride,
Calcium chloride, magnesium chloride, beryllium chloride,
Aluminum chloride, titanium tetrachloride, vanadium chloride, chromium chloride, manganese chloride, iron chloride, cobalt chloride, nickel chloride, copper chloride, zinc chloride, strontium chloride, yttrium chloride, zirconium chloride, molybdenum chloride,
Ruthenium chloride, rhodium chloride, palladium chloride, silver chloride, cadmium chloride, tin chloride, tellurium chloride, cesium chloride, barium chloride, cerium chloride, lead chloride, tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, Chloride salts such as triethanolamine hydrochloride, sodium bromide, potassium bromide, lithium bromide, ammonium bromide, tetramethylammonium bromide, tetraethylammonium bromide, tetrabutylammonium bromide, triethanolamine bromide Hydrochloride,
Sodium iodide, potassium iodide, lithium iodide,
Ammonium iodide, tetramethylammonium / iodo, tetraethylammonium / iodo, tetrabutylammonium / iodo, triethanolamine / hydroiodide, sodium sulfate, potassium sulfate, lithium sulfate, ammonium sulfate, tetramethylammonium / sulfate, tetraethyl Ammonium sulfate, tetrabutylammonium sulfate, triethanolamine sulfate, sodium nitrate, potassium nitrate, lithium nitrate, ammonium nitrate, tetramethylammonium nitrate,
Tetraethylammonium / nitrate, tetrabutylammonium / nitrate, triethanolamine / nitrate, sodium phosphate, potassium phosphate, lithium phosphate, ammonium phosphate, sodium carbonate, potassium carbonate, lithium carbonate, ammonium carbonate, tetramethylammonium / carbonate Salt, tetraethylammonium carbonate, tetrabutylammonium carbonate, triethanolamine carbonate, sodium borate, potassium borate, lithium borate, ammonium borate, sodium benzenesulfonate, potassium benzenesulfonate, benzenesulfone Lithium acid, ammonium benzenesulfonate,
Tetramethylammonium benzenesulfonate, tetraethylammonium benzenesulfonate, tetrabutylammonium benzenesulfonate, triethanolamine benzenesulfonate, sodium p-toluenesulfonate, potassium p-toluenesulfonate, p -Lithium toluene sulfonate, ammonium p-toluene sulfonate, tetramethyl ammonium p
-Toluenesulfonate, tetraethylammonium
p-toluenesulfonate, tetrabutylammonium / p-toluenesulfonate, triethanolamine
p-toluenesulfonic acid salt, sodium benzoate, potassium benzoate, lithium benzoate, ammonium benzoate, tetramethylammonium benzoate, tetraethylammonium benzoate, tetrabutylammonium benzoate, triethanolamine. Benzoate, sodium oxalate, potassium oxalate, lithium oxalate, ammonium oxalate, tetramethylammonium oxalate, tetraethylammonium oxalate, tetrabutylammonium oxalate, triethanolamine, oxalic acid Salt, sodium acetate, potassium acetate, lithium acetate, ammonium acetate, tetramethylammonium acetate, tetraethylammonium acetate, tetrabutylammonium acetate, triethanolamine Salt, sodium propionate,
Examples include potassium propionate, lithium propionate, ammonium propionate, tetramethylammonium propionate, tetraethylammonium propionate, tetrabutylammonium propionate, and triethanolamine propionate.

Of these, sodium chloride, potassium chloride, lithium chloride, ammonium chloride, tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, triethanolamine hydrochloride, sodium bromide, potassium bromide, Lithium bromide, ammonium bromide, tetramethylammonium bromide, tetraethylammonium bromide, tetrabutylammonium bromide, triethanolamine hydrobromide, sodium iodide, potassium iodide, ammonium iodide, tetramethylammonium・ Iodine, tetraethylammonium ・ iodo, tetrabutylammonium ・ iodo, triethanolamine ・ hydroiodide, sodium sulfate, potassium sulfate, ammonium sulfate , Tetramethylammonium
Sulfate, tetraethylammonium / sulfate, tetrabutylammonium / sulfate, triethanolamine / sulfate, sodium nitrate, potassium nitrate, ammonium nitrate, tetramethylammonium / nitrate, tetraethylammonium / nitrate, tetrabutylammonium / nitrate, triethanolamine・ Nitrate, sodium phosphate, potassium phosphate, ammonium phosphate, sodium carbonate, potassium carbonate, lithium carbonate, ammonium carbonate, tetramethylammonium ・ carbonate, tetraethylammonium ・ carbonate, tetrabutylammonium ・ carbonate, triethanolamine・ Carbonates, sodium borate, potassium borate, ammonium borate, sodium benzenesulfonate, potassium benzenesulfonate, benzenesulfonate Monium, tetramethylammonium benzenesulfonate, tetraethylammonium benzenesulfonate, tetrabutylammonium benzenesulfonate, triethanolamine benzenesulfonate, sodium p-toluenesulfonate, potassium p-toluenesulfonate , Ammonium p-toluenesulfonate, tetramethylammonium.p
-Toluenesulfonate, tetraethylammonium
p-toluenesulfonate, tetrabutylammonium / p-toluenesulfonate, triethanolamine
p-toluenesulfonate, sodium benzoate, potassium benzoate, ammonium benzoate, tetramethylammonium benzoate, tetraethylammonium
Benzoate, tetrabutylammonium benzoate,
Triethanolamine / benzoate, sodium oxalate, potassium oxalate, ammonium oxalate, sodium acetate, potassium acetate, ammonium acetate, tetramethylammonium acetate, tetraethylammonium acetate, tetrabutylammonium acetate, tributylamine Preference is given to ethanolamine / acetate, sodium propionate, potassium propionate, etc., especially sodium chloride, potassium chloride, ammonium chloride, tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, triethanolamine hydrochloride , Sodium sulfate, potassium sulfate, ammonium sulfate, tetramethylammonium sulfate, tetraethylammonium sulfate, tetrabutylammonium sulfate Salt, triethanolamine sulfate, sodium phosphate, potassium phosphate, ammonium phosphate, sodium carbonate, potassium carbonate, ammonium carbonate, sodium borate, potassium borate, ammonium borate, sodium benzenesulfonate, benzenesulfonic acid Potassium, ammonium benzenesulfonate,
Tetramethylammonium benzenesulfonate, tetraethylammonium benzenesulfonate, tetrabutylammonium benzenesulfonate, triethanolamine benzenesulfonate, sodium p-toluenesulfonate, potassium p-toluenesulfonate, p -Ammonium toluenesulfonate, tetramethylammonium / p-toluenesulfonate, tetraethylammonium / p-toluenesulfonate, tetrabutylammonium / p-toluenesulfonate, triethanolamine / p-toluenesulfonate, benzoic acid Sodium oxalate, potassium benzoate, ammonium benzoate, sodium oxalate, potassium oxalate, ammonium oxalate, sodium acetate, potassium acetate, ammonium acetate, professional Sodium propionic acid, potassium propionate Konomashikui.

The concentration of the salt used is preferably from 0.01 to 20% by weight, more preferably from 0.1 to 5% by weight. If the concentration is too low, the effect is small, and if the concentration is too high, salt may be mixed into the product.

The reagents that can be used to open the remaining imide ring are not particularly limited, but generally alkaline water is used.

The alkaline water to be used is not particularly limited, but alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, alkali metal carbonates such as sodium carbonate, potassium carbonate and lithium carbonate, and sodium hydrogen carbonate And alkali metal bicarbonates such as potassium bicarbonate; alkali metal acetates such as sodium acetate and potassium acetate; alkali metal salts such as sodium oxalate; and aqueous ammonia. Among them, sodium hydroxide and potassium hydroxide which are inexpensive are preferable.

The pH of the reaction solution for the alkali-opening of the remaining imide ring varies depending on the concentration of alkaline water. If the pH is too low, the reaction will be slow and not practical. Generally, 7.5 to 13 is preferable, and 9 to 12 is more preferable.

The ring opening reaction of the imide ring of the crosslinked polysuccinimide is performed in water at 5 to 100 ° C. Especially 10
60 ° C. is preferred.

[6] Post-Treatment of Cross-Linked Polyaspartic Resin The post-treatment of the cross-linked polyaspartic resin produced by subjecting the imide ring of the cross-linked polysuccinimide to an alkaline hydrolysis reaction is not particularly limited. For example, treatments such as neutralization, salt exchange, drying, purification, granulation, and surface cross-linking treatment may be performed as necessary. Hereinafter, the processes of neutralization, salt exchange, and drying will be particularly described.

[6-1] Neutralization treatment of crosslinked polyaspartic acid-based resin Neutralization treatment of crosslinked polyaspartic acid-based resin may be performed as necessary. However, the reaction solution containing the crosslinked polyaspartic acid-based resin after the hydrolysis reaction is usually alkaline. Therefore, it is preferable to neutralize by adding an acid or the like. By this neutralization treatment, a carboxyl group present in the molecule of the crosslinked polyaspartic acid-based resin can be converted into a salt. Although the degree of neutralization is not particularly limited, generally, the proportion of carboxyl groups forming a salt is 0 to 50% based on the total number of all aspartic acid residues in the molecule of the crosslinked polyaspartic acid-based resin. Preferably, 0 to 30
% Is more preferred.

The method of the neutralization treatment is not particularly limited, but a method of adjusting the pH by adding an acid after the hydrolysis reaction is generally used. Specific examples of the acid include carboxylic acids such as hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, carbonic acid, phosphoric acid, formic acid, acetic acid, propionic acid, oxalic acid, and benzoic acid. And sulfonic acids such as methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid and toluenesulfonic acid, and phosphonic acids such as benzenephosphonic acid.

[6-2] Salt exchange treatment of cross-linked polyaspartic acid-based resin When the carboxyl group present in the molecule of the cross-linked polyaspartic acid-based resin is converted into a salt by neutralization treatment, if necessary, the salt may be used. Can be exchanged for another type of salt.

Specific examples of the reagent used for this salt exchange include, for example, alkali metal salts, ammonium salts, amine salts and the like. More specifically, sodium, potassium, alkali metal salts such as lithium, tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium,
Tetrapentylammonium, tetrahexylammonium, ethyltrimethylammonium, trimethylpropylammonium, butyltrimethylammonium, pentyltrimethylammonium, hexyltrimethylammonium, cyclohexyltrimethylammonium,
Ammonium salts such as benzyltrimethylammonium, triethylpropylammonium, triethylbutylammonium, triethylpentylammonium, triethylhexylammonium, cyclohexyltriethylammonium, benzyltriethylammonium, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine , Triethanolamine, tripropanolamine, tributanolamine, tripentanolamine, trihexanolamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dicyclohexylamine, dibenzylamine, ethylmethylamine , Methylpropylamine, spot Methylamine, methyl pentyl amine, methyl hexyl amine, methyl amine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, octylamine, decylamine,
Examples thereof include amine salts such as dodecylamine and hexadecylamine.

Of these, the higher the molecular weight, the higher the molecular weight per monomer unit and the smaller the water absorption per unit weight. Therefore, the smaller the molecular weight, the better. When there is a possibility of touching human skin or the like, it is preferable that toxicity is low. From these points, it is preferable to use sodium, potassium, lithium, ammonium and triethanolamine, and it is particularly preferable to use sodium and potassium from the viewpoint of cost.

[6-3] Drying Treatment of Crosslinked Polyaspartic Acid Resin The method of drying the crosslinked polyaspartic acid resin is not particularly limited. For example, known methods such as hot air drying, drying with specific steam, microwave drying, reduced pressure drying, drum dryer drying, and drying by azeotropic dehydration in a hydrophobic organic solvent can be used. The drying temperature is generally 20 to
200 ° C is preferable, and 50 to 120 ° C is more preferable.

The dried crosslinked polyaspartic acid-based resin may be further subjected to a purification treatment, a granulation treatment, a surface crosslinking treatment and the like.

[7] Shape and Particle Diameter of Crosslinked Polyaspartic Acid Resin The shape of the crosslinked polyaspartic acid resin is irregularly crushed, spherical, granular, granular, granulated, scaly, massive, and pearl. Various shapes such as a powder, a fine powder, a fiber, a rod, a film, and a sheet can be used, and a preferable shape can be used depending on the application. Further, it may be a fibrous base material, a porous material, a foam, or a granulated material.

[8] Shape of Crosslinked Polyaspartic Acid Resin Specific examples of the shape of the crosslinked polyaspartic acid resin include irregularly crushed, spherical, granular, granular, granulated, scaly, massive, Various shapes such as a pearl shape, a fine powder shape, a fibrous shape, a bar shape, a film shape, a sheet shape and the like can be mentioned, and a preferable shape can be selected according to the use. Further, it may be a fibrous base material, a porous body, a foam, a granulated material, or the like.

[9] Particle size of cross-linked polyaspartic resin Resin particle size (average particle diameter)
Is not particularly limited, and a preferred particle size can be selected according to the application. For example, when used in a disposable diaper, it is desired that a high absorption rate and gel blocking do not occur. Therefore, the average particle size is preferably 100 to 1000 µm, more preferably 150 to 600 µm. Also, for example,
When used for kneading into a resin such as a water-stopping material, the average particle diameter is preferably 1 to 10 μm, and when used for a water retention material for agriculture and horticulture, in consideration of dispersibility with soil, 100 μm to
5 mm is preferred.

[10] Form of Use of Crosslinked Polyaspartic Acid Resin The form of use of the crosslinked polyaspartic acid resin is not particularly limited, and may be used alone or in combination with other materials. .

For example, when used in combination with another resin,
A method of kneading with a thermoplastic resin and molding by injection molding or the like, a method of mixing a monomer of the constituent resin with an acidic polyamino acid-based resin and, if necessary, an initiator, and polymerizing with light or heat, etc., and a resin and a crosslinked polyasparagine. Dispersing the acid-based resin in a solvent, casting, removing the solvent, mixing the prepolymer and the cross-linked polyaspartic resin, then cross-linking, mixing the resin and the cross-linked polyaspartic resin,
There is a method of crosslinking and the like.

The molded product of the crosslinked polyaspartic acid resin is not particularly limited, and can be used as a solid, a sheet, a film, a fiber, a nonwoven fabric, a foam, a rubber and the like. Also, the molding method is not particularly limited.

On the other hand, the crosslinked polyaspartic acid-based resin is
It may be used alone or in a composite with other materials. The structure of the complex is not particularly limited, for example,
There are a method of sandwiching a pulp layer, a nonwoven fabric, or the like to form a sandwich structure, a method of forming a multilayer structure using a resin sheet or a film as a support, and a method of casting a resin sheet to form a two-layer structure. For example, if a crosslinked polyaspartic acid-based resin is formed into a sheet, a water-absorbing sheet (including a water-absorbing film) can be obtained.

Further, the crosslinked polyaspartic acid-based resin is
If necessary, it may be used by mixing with one or more other water-absorbing resins. If necessary, an inorganic compound such as salt, colloidal silica, white carbon, ultrafine silica, titanium oxide powder, or an organic compound such as a chelating agent may be added. In addition, oxidizing agents, antioxidants, reducing agents,
An ultraviolet absorber, an antibacterial agent, a bactericide, a fungicide, a fertilizer, a fragrance, a deodorant, a pigment, and the like may be mixed.

The crosslinked polyaspartic acid resin can be used as a gel or as a solid. For example, when used as a water retention material for agricultural and horticultural use, a cut flower life-promoting agent, a gel fragrance, a gel deodorant, etc., it is used as a gel, and an absorbent for disposable diapers is used as a solid.

[11] Use of Crosslinked Polyaspartic Acid Resin The use of the crosslinked polyaspartic acid resin is not particularly limited, but it can be used for any of the applications in which conventional water-absorbing resins can be used.

For example, sanitary articles such as sanitary articles, disposable diapers, breast milk pads, disposable rags, dressings for protecting wounds, medical articles such as medical underpads, cataplasms,
Pet seats, portable toilets, gel air fresheners, gel deodorants, sweat-absorbing fibers, household items such as disposable warmers, toiletries such as shampoos, set gels, moisturizers, water retention materials for agriculture and horticulture, Agricultural and horticultural supplies, food trays, etc., for life extension of cut flowers, floral foam (fixed material for cut flowers), nursery beds, hydroponic vegetation sheets, seed tapes, fluid seeding media, dew condensation prevention agricultural sheets, etc. Food packaging materials such as freshness preservation materials, drip absorbent sheets, cold insulation materials,
Transportation materials such as water-absorbent sheets for transporting fresh vegetables, building materials for preventing dew condensation, sealing materials for civil engineering and construction, anti-sedimentation agents for shielding methods, concrete admixtures, civil engineering and construction materials such as gaskets and packing, and electronic equipment , Sealing materials such as optical fibers, waterproof materials for communication cables, materials related to electrical equipment such as ink jet recording paper, coagulants for sludge, water treatment agents such as gasoline and oil dehydration, water removal agents, etc., printing pastes, Water-swellable toys, artificial snow, sustained-release fertilizers, sustained-release pesticides,
Sustained-release drugs, humidity control materials, antistatic agents, and the like.

[0134]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples. In the following Examples and Comparative Examples, “parts” means “parts by weight”. The amount of water absorption in the examples was measured by the following tea bag method.

(1) Tea Bag Method The amount of water absorption was measured for distilled water and physiological saline. That is, in the case of distilled water, about 0.05
Parts, in the case of physiological saline, about 0.1 part of a water-absorbent resin is placed in a non-woven tea bag (80 mm × 50 mm), immersed in an excess of the corresponding solution to swell the resin for 1 hour, The bag was pulled out and drained for 1 minute, and the weight of the tea bag containing the swollen resin was measured. When the same operation was performed using only a tea bag as a blank, the value obtained by subtracting the weight of the blank and the weight of the water-absorbent resin from the weight and dividing the value by the weight of the water-absorbent resin was used as the water absorption (g / resin 1).
g). The physiological saline is a 0.9% by weight aqueous sodium chloride solution.

[Example 1] 7.2 parts of lysine methyl ester dihydrochloride and 22.6 parts of lysine monohydrochloride were dispersed in 40 parts of distilled water, and 7.8 parts of caustic soda was added little by little. Then, a lysine aqueous solution was prepared. On the other hand, under a nitrogen stream,
100 parts of a polysuccinimide having a weight-average molecular weight of 96,000 is dissolved in 400 parts of N, N-dimethylformamide (hereinafter, referred to as DMF). 400 parts of toluene as an agent (poor solvent) was charged to disperse the polysuccinimide, and reacted for 2 hours. After the reaction, the precipitate was collected by suction filtration, washed with toluene, and dried at 60 ° C. for 2 hours to obtain a crosslinked polysuccinimide.

120 parts of this crosslinked polysuccinimide was
It was dispersed in 400 parts of distilled water and 400 parts of methanol, and 130 parts of a 27% by weight aqueous sodium hydroxide solution was added dropwise over 2 hours. After the dropwise addition, the mixture was further stirred for 2 hours, and neutralized to pH 7 using 7% by weight aqueous hydrochloric acid. After neutralization, the mixture was discharged into 300 parts of methanol and stirred for 1 hour. The precipitate was collected by filtration and dried at 60 ° C. to obtain 125 parts of a crosslinked polyaspartic acid-based resin as a water-absorbing polymer.

The water absorption of the crosslinked polyaspartic resin was 890 times with distilled water and 71 times with physiological saline.

Example 2 Lysine monohydrochloride (37.6 parts) was dispersed in distilled water (80 parts), and caustic soda (10.3 parts) was added for neutralization to prepare a lysine aqueous solution. On the other hand, under a nitrogen stream, polysuccinimide 10 having a weight average molecular weight of 96,000 was used.
0 parts was dissolved in 400 parts of DMF, an aqueous solution of lysine was added to this solution, and the mixture was stirred at room temperature for 10 minutes. 400 parts of methanol as a dispersant (poor solvent) was charged and dispersed, and reacted for 20 hours. After the reaction, the precipitate was collected by suction filtration and washed with methanol to obtain a wet cake of crosslinked polysuccinimide.

The cross-linked polysuccinimide of wet
The cake was dispersed in 400 parts of distilled water and 400 parts of methanol, and 122.1 parts of a 27% by weight aqueous sodium hydroxide solution was added dropwise over 2 hours. After the dropwise addition, the mixture was further stirred for 2 hours, and then neutralized to pH 7 using 7% by weight aqueous hydrochloric acid. After neutralization, the mixture was discharged into 300 parts of methanol and stirred for 1 hour. This precipitate was collected by filtration, dried at 60 ° C., and crosslinked polyaspartic resin 14 as a water-absorbing polymer.
0 parts were obtained.

The water absorption of the crosslinked polyaspartic resin was 860 times with distilled water and 70 times with physiological saline.

Example 3 Instead of an aqueous lysine solution, 3.0 parts of hexamethylenediamine was used as a crosslinking agent in distilled water 1
A wet cake of crosslinked polysuccinimide was obtained in the same manner as in Example 2 except that an aqueous solution dissolved in 0 parts was used.

The cross-linked polysuccinimide of wet
The cake was hydrolyzed, neutralized, recovered and dried in the same manner as in Example 2 except that 148.8 parts of a 27% by weight aqueous solution of caustic soda was used to obtain a crosslinked polyaspartic acid-based water-absorbing polymer. 108 parts of resin were obtained.

The water absorption of the crosslinked polyaspartic resin was 880 times with distilled water and 70 times with physiological saline.

Example 4 The procedure of Example 1 was repeated, except that a dispersion prepared by dispersing 3.5 parts of m-xylylenediamine in 20 parts of toluene was used as a crosslinking agent instead of the aqueous lysine solution. The steps before drying were performed to obtain a wet cake of crosslinked polysuccinimide.

The crosslinked polysuccinimide of wet
The cake was hydrolyzed, neutralized, recovered and dried in the same manner as in Example 2 except that 148.8 parts of a 27% by weight aqueous solution of caustic soda was used to obtain a crosslinked polyaspartic acid-based water-absorbing polymer. 110 parts of resin were obtained.

The water absorption of the crosslinked polyaspartic resin was 760 times with distilled water and 65 times with physiological saline.

[Example 5] 75.3 parts of lysine monohydrochloride were suspended in 150 parts of distilled water, and neutralized by adding 40.6 parts of caustic soda to prepare a lysine suspension. On the other hand, 100 parts of polysuccinimide having a weight-average molecular weight of 96,000 and 500 parts of distilled water as a dispersant (poor solvent) were charged into a high-speed stirrer having a blade with a blade, and ground at 15,000 rpm for 1 hour. Then, the lysine suspension was added, and the mixture was further stirred for 20 hours.
After the reaction, 500 parts of methanol was added to obtain a dispersion of crosslinked polysuccinimide.

In the dispersion of the crosslinked polysuccinimide,
13.7 parts of a 27% by weight aqueous sodium hydroxide solution was added dropwise over 2 hours. After the dropwise addition, the mixture was further stirred for 2 hours, and neutralized to pH 7 using 7% by weight aqueous hydrochloric acid. After neutralization, the mixture was discharged into 300 parts of methanol and stirred for 1 hour. The precipitate was collected by filtration and dried at 60 ° C. to obtain 95 parts of a crosslinked polyaspartic acid-based resin as a water-absorbing polymer.

The water absorption of the crosslinked polyaspartic resin was 460 times with distilled water and 63 times with physiological saline.

Example 6 Lysine monohydrochloride (56.4 parts) was dispersed in distilled water (100 parts), and caustic soda (25.5 parts) was added little by little to neutralize the mixture, thereby preparing a lysine suspension. on the other hand,
100 parts of a polysuccinimide having a weight-average molecular weight of 96,000 and 500 parts of methanol as a dispersant (poor solvent) were charged into a high-speed stirrer having a blade with a blade, and 15,000
pm for 1 hour, lysine suspension was added,
After stirring for 0 hour, a dispersion of crosslinked polysuccinimide was obtained.

The dispersion of the crosslinked polysuccinimide was
500 parts of distilled water was added, and 106.8 parts of a 27% by weight aqueous sodium hydroxide solution was further added dropwise over 2 hours. After the dropwise addition, the mixture was further stirred for 2 hours, and neutralized to pH 7 using 7% by weight aqueous hydrochloric acid. After neutralization, the mixture was discharged into 300 parts of methanol and stirred for 1 hour. The precipitate was collected by filtration and
It dried at 90 degreeC, and obtained 90 parts of crosslinked polyaspartic acid type resins which are water absorbing polymers.

The water absorption of the crosslinked polyaspartic resin was 520 times with distilled water and 65 times with physiological saline.

Example 7 48.0 parts of lysine methyl ester dihydrochloride were suspended in 80 parts of distilled water, and sodium hydroxide 1
6.5 parts were added little by little to neutralize to prepare a lysine methyl ester suspension. On the other hand, under nitrogen stream, 100 parts of polysuccinimide having a weight average molecular weight of 96,000 was added to DMF 40
0 parts, and 400 parts of methanol as a dispersant (poor solvent) was added to obtain a dispersed state. To this dispersion, a lysine methyl ester suspension was added, the mixture was stirred at room temperature for 20 hours, and the precipitate was collected by suction filtration, washed with methanol,
A wet cake of crosslinked polysuccinimide was obtained.

The crosslinked polysuccinimide was prepared by a wet method.
The cake was dispersed in 400 parts of distilled water and 400 parts of methanol, and 122.1 parts of a 27% by weight aqueous sodium hydroxide solution was added dropwise over 2 hours. After the dropwise addition, the mixture was further stirred for 2 hours, and neutralized to pH 7 using 7% by weight aqueous hydrochloric acid. After neutralization, the mixture was discharged into 300 parts of methanol and stirred for 1 hour. The precipitate was collected by filtration, dried at 60 ° C., and crosslinked polyaspartic acid resin 98 as a water-absorbing polymer.
Got a part.

The water absorption of the crosslinked polyaspartic acid resin was 450 times with distilled water and 64 times with physiological saline.

Example 8 7.2 parts of lysine methyl ester dihydrochloride and 22.6 parts of lysine monohydrochloride were dissolved in distilled water 4
0 parts, and 7.8 parts of caustic soda was added little by little to neutralize to prepare an aqueous lysine solution. On the other hand, 100 parts of polysuccinimide having a weight average molecular weight of 96,000 was added to a mixed liquid of 400 parts of DMF and 400 parts of methanol as a dispersant (poor solvent) under a nitrogen stream to form a dispersed state. An aqueous lysine solution was added to the dispersion, and the mixture was stirred at room temperature for 40 hours, suction-filtered, and the precipitate was collected and washed with methanol to obtain a wet cake of crosslinked polysuccinimide.

The cross-linked polysuccinimide of wet
The cake was dispersed in 400 parts of distilled water and 400 parts of methanol, and 130 parts of a 27% by weight aqueous solution of caustic soda was added to 2 parts.
It was dropped over time. After the addition, the mixture was further stirred for 2 hours.
Neutralized to pH 7 using a weight% aqueous hydrochloric acid solution. After neutralization, the mixture was discharged into 300 parts of methanol and stirred for 1 hour.
The precipitate was collected by filtration and dried at 60 ° C. to obtain 94 parts of a crosslinked polyaspartic acid-based resin as a water-absorbing polymer.

The water absorption of the crosslinked polyaspartic resin was 660 times with distilled water and 67 times with physiological saline.

Example 9 24.0 parts of lysine methyl ester dihydrochloride and 18.8 parts of lysine monohydrochloride were dispersed in 40 parts of distilled water, and 12.4 parts of caustic soda was added little by little to neutralize. Then, an aqueous lysine solution was prepared. On the other hand, under a nitrogen stream, polysuccinimide 10 having a weight average molecular weight of 96,000 was used.
0 parts was dissolved in 400 parts of DMF, an aqueous solution of lysine was added to the solution, and the mixture was stirred at room temperature for 10 minutes.
The mixture was charged over 30 minutes into 400 parts of toluene as a dispersant (poor solvent) in a stirrer equipped with a high-speed stirring blade rotating at rpm. After further reacting for 10 hours, the precipitate was collected by suction filtration, washed with toluene, and dried at 60 ° C. for 2 hours to obtain a crosslinked polysuccinimide.

130 parts of this crosslinked polysuccinimide was
It was dispersed in 400 parts of distilled water and 400 parts of methanol, and 122.1 parts of a 27% by weight aqueous sodium hydroxide solution was added dropwise over 2 hours. After the dropwise addition, the mixture was further stirred for 2 hours and neutralized to pH 7 using 7% by weight aqueous hydrochloric acid. After neutralization, the mixture was discharged into 300 parts of methanol and stirred for 1 hour. The precipitate was collected by filtration and dried at 60 ° C. to obtain 125 parts of a crosslinked polyaspartic acid-based resin as a water-absorbing polymer.

The water absorption of the crosslinked polyaspartic resin was 620 times with distilled water and 65 times with physiological saline.

Example 10 Lysine monohydrochloride 28.2
Was dispersed in 40 parts of distilled water, and 9.8 parts of caustic soda was added little by little to prepare an aqueous lysine solution. On the other hand, 100 parts of polysuccinimide having a weight-average molecular weight of 96,000 was dissolved in 400 parts of DMF, and 20 parts of sodium dodecylbenzenesulfonate and 500 parts of heptane as a dispersant (poor solvent) were charged into a high-speed stirrer. Then, an aqueous lysine solution was charged over 20 minutes while stirring at 15000 rpm. The mixture was further stirred for 20 hours to obtain a dispersion of crosslinked polysuccinimide. This crosslinked polysuccinimide dispersion is filtered,
500 parts of distilled water was added to the obtained solid, and 32.7 parts of a 27% by weight aqueous solution of caustic soda was added dropwise over 2 hours. After the dropwise addition, the mixture was further stirred for 2 hours, and neutralized to pH 7 using 7% by weight aqueous hydrochloric acid. After neutralization, methanol 3
00 parts and stirred for 1 hour. This precipitate was collected by filtration and dried at 60 ° C. to obtain 155 parts of a crosslinked polyaspartic acid-based resin as a water-absorbing polymer.

The water absorption of the crosslinked polyaspartic resin was 480 times with distilled water and 63 times with physiological saline.

[Comparative Example 1] 7.2 parts of lysine methyl ester dihydrochloride and 22.6 parts of lysine monohydrochloride were mixed with distilled water 4
0 parts, and 7.8 parts of caustic soda was added little by little to neutralize to prepare an aqueous lysine solution. On the other hand, under nitrogen stream, 100 parts of polysuccinimide having a weight average molecular weight of 96,000 was dissolved in 400 parts of DMF, an aqueous lysine solution was added to this solution, and the mixture was stirred at room temperature. However, the viscosity of the reaction solution became remarkably thick during the stirring, and the stirring became impossible. Therefore, the stirring was stopped and the reaction was carried out for 30 hours to obtain a gel of the reaction product.

The gel of the reaction product was added to 1000 parts of methanol and stirred at room temperature, but the stirring speed could not be increased due to the large size of the precipitated particles, and it took more than one day for the whole crosslinked product to be loosened. , Operation was difficult. The precipitate thus obtained was collected by suction filtration and washed with methanol and then with water to obtain a wet cake of crosslinked polysuccinimide.

The wet crosslinked polysuccinimide
The cake is suspended in 15 parts of distilled water and 15 parts of methanol,
7.3 parts of a 24% by weight aqueous sodium hydroxide solution was added dropwise so that the pH of the suspension was in the range of 11 to 12.
After the pH did not decrease, diluted hydrochloric acid was added to
Was added until 7. The resulting mixture was discharged into 100 parts of methanol, and the resulting precipitate was dried and pulverized,
7.6 parts of a crosslinked polyaspartic acid-based resin as a water-absorbing polymer was obtained.

The water absorption of the crosslinked polyaspartic acid resin was 380 times with distilled water and 59 times with physiological saline.

[Comparative Example 2] 6 parts of lysine methyl ester dihydrochloride was suspended in 200 parts of DMF, and neutralized with 6 parts of triethylamine. A solution prepared by dissolving 50 parts of polysuccinimide having a weight average molecular weight of 130,000 in 250 parts of DMF was added to the suspension, and the mixture was stirred at room temperature for 1 hour, and then, 12 parts of triethylamine was appropriately dropped and reacted at room temperature for 40 hours. Was. The reaction solution was discharged into ethanol and dried to obtain 50 parts of a crosslinked polysuccinimide.

26 parts of the crosslinked polysuccinimide were suspended in 5000 parts of distilled water, and the remaining imide ring was hydrolyzed while adjusting the pH to 9 to 11 by appropriately lowering the pH of a 2N aqueous solution of NaOH. The obtained reaction solution was discharged into ethanol, and the formed precipitate was filtered and dried to obtain 86 parts of a crosslinked polyaspartic acid-based resin as a water-absorbing polymer. The water absorption of the crosslinked polyaspartic acid resin was 110 times with distilled water and 30 times with physiological saline.

[Comparison and Discussion of Examples 1 to 10 and Comparative Examples 1 and 2] Comparative Example 1 is a conventional method for producing a crosslinked polyaspartic acid exhibiting a high water absorption.
Comparative Example 2 is a conventional method for producing a crosslinked polyaspartic acid with high productivity. However, in Comparative Examples 1 and 2, no good results were obtained overall because no dispersant was used. Specifically, in Comparative Example 1, the productivity was significantly reduced, and in Comparative Example 2, the water absorption of the resin was significantly reduced.

In contrast, in Examples 1 to 10, in each case, the crosslinking reaction was carried out in a dispersed state using a dispersant, so that the crosslinked polyaspartic acid exhibiting a high water absorption was used.
It could be manufactured with high productivity.

As described above, by using the dispersant in the crosslinking reaction and reacting the polysuccinimide in a dispersed state with the crosslinking agent, effects can be obtained in terms of water absorption and productivity.

[0174]

As described above, for disposable diapers,
As a water absorber used for horticulture, etc., it is suitable for industrial production by performing a crosslinking reaction in a dispersed state in the production of environmentally friendly crosslinked polyaspartic acid by being biodegradable after use or disposal. A water-absorbent resin having a high water absorption can be produced.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroaki Tamaya 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Chemicals, Inc.

Claims (14)

[Claims] 1. A method for producing a crosslinked polyaspartic acid resin, comprising subjecting a polysuccinimide in a dispersed state by a dispersant to a crosslinking reaction with a crosslinking agent to hydrolyze an imide ring. 2. The method for producing a crosslinked polyaspartic resin according to claim 1, wherein the crosslinking agent is a polyamine. 3. The method for producing a crosslinked polyaspartic acid-based resin according to claim 1, wherein the dispersant is a water-miscible organic solvent. 4. The method for producing a crosslinked polyaspartic acid-based resin according to claim 1, wherein the dispersant is a water-immiscible organic solvent. 5. The crosslinker according to claim 1, wherein the dispersant is a poor solvent selected from the group consisting of an organic solvent and water that cannot substantially completely dissolve the polysuccinimide. A method for producing a polyaspartic acid-based resin. 6. A polysuccinimide dissolved in a good solvent which is an organic solvent capable of substantially completely dissolving polysuccinimide, wherein the polysuccinimide is substantially completely insoluble in an organic solvent and water. The polysuccinimide in the dispersed state is reacted with a crosslinking agent by adding and dispersing a selected poor solvent.
6. The method for producing a crosslinked polyaspartic acid-based resin according to any one of the above items. 7. A poor solvent selected from the group consisting of a good solvent, which is an organic solvent capable of substantially completely dissolving polysuccinimide, and an organic solvent, which cannot substantially completely dissolve polysuccinimide, and water. The method for producing a crosslinked polyaspartic resin according to any one of claims 1 to 5, wherein the polysuccinimide is dispersed in a mixed solvent and reacted with a crosslinking agent. 8. An organic solvent in which the polysuccinimide cannot be substantially completely dissolved after dissolving the polysuccinimide in a good solvent which is an organic solvent capable of substantially completely dissolving the polysuccinimide and adding a crosslinking agent. The method for producing a crosslinked polyaspartic acid-based resin according to any one of claims 1 to 5, wherein a poor solvent selected from the group consisting of a solvent and water is added, dispersed, and reacted with a crosslinking agent. 9. A solution obtained by dissolving polysuccinimide in a good solvent which is an organic solvent capable of substantially completely dissolving polysuccinimide and adding a cross-linking agent cannot substantially completely dissolve polysuccinimide. The method for producing a crosslinked polyaspartic resin according to any one of claims 1 to 5, wherein the resin is dispersed in a poor solvent selected from the group consisting of an organic solvent and water and reacted with a crosslinking agent. 10. The “dispersed state” of polysuccinimide
Is a solid / liquid dispersion of a solid phase containing a polysuccinimide and a liquid phase containing a dispersant, the production of a crosslinked polyaspartic resin according to any one of claims 1 to 9. Method. 11. The “solid phase containing polysuccinimide” is expressed by mixing a good solvent containing polysuccinimide and a poor solvent miscible with the good solvent. The method for producing a crosslinked polyaspartic acid-based resin according to claim 10, wherein: 12. The “dispersed state” of polysuccinimide
Is a liquid / liquid dispersion of a liquid phase obtained by dissolving polysuccinimide in a good solvent, and a liquid phase containing a dispersant, and wherein the crosslinked polyaspartic acid system according to any one of claims 1 to 9 is used. Method of manufacturing resin. 13. “Liquid / liquid dispersion” means that when a liquid phase obtained by dissolving polysuccinimide in a good solvent and a poor solvent immiscible with the good solvent are mixed, The method for producing a crosslinked polyaspartic acid-based resin according to claim 12, wherein the resin is expressed by not dissolving. 14. A crosslinked polyaspartic acid-based resin produced by the production method according to claim 1.