JPH11181082A - Polymer and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polymer having biodegradability, exhibiting little change in the water absorption even to a salt-containing aqueous solution, usable over a wide pH range and useful e.g. as a water-absorbing material for agricultural and horticultural use by including a recurring unit having a pendant group containing a nonionic polar group. SOLUTION: The objective polymer is a crosslinked acidic polyamino acid polymer containing (A) a recurring unit of formula I R is a pendant group having a nonionic polar group [e.g. a group of formula NR1 "R2 " (R1 " and R2 " are each H, an alkyl, an aralkyl or an aryl), a group of formula CONR1 "R2 ", a group of formula SR1 " or a polyether group]; X is a group of formula NR' (R' is R1 "), O or S; (n) is 1 or 2} or (B) a recurring unit of formula II. The polymer is produced e.g. by reacting a crosslinked polysuccinimide with an amine, an alcohol or a thiol having nonionic polar group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel decomposable water-absorbing resin and a method for producing the same. For more information,
The present invention relates to a crosslinked acidic polyamino acid-based resin which has biodegradability, does not reduce water absorption even in an aqueous solution containing a salt, and can be used in a wide pH range, and a method for producing the same. More specifically, the present invention relates to a water-absorbing resin which is used for thickeners, water-stopping materials, agricultural and horticultural purposes, and is biodegradable after use or disposal, thereby being environmentally friendly.

[0002]

2. Description of the Related Art [Technical background of water-absorbent resin] A water-absorbent resin is a resin that can absorb water from several tens to several thousand times its own weight. Supplies, dressings for wound protection, medical supplies such as medical underpads, cataplasms, pet seats, portable toilets, gel fragrances, gel deodorants, sweat absorbing fibers, disposable warmers and other household items, shampoos, Set gels, toiletries such as moisturizers, water retention materials for agriculture and horticulture, cut flower life-promoting agents, floral foam (cutting flower fixing material), nursery beds for nursery, hydroponics, vegetation sheets, seed tapes, fluids Agricultural and horticultural products such as agricultural sheets for preventing sowing and dew condensation, freshness-retaining materials for food trays, food packaging materials such as drip-absorbent sheets, cooling materials, and transport materials such as water-absorbent sheets for transporting fresh vegetables Building materials for preventing dew condensation, sealing materials for civil engineering and construction, anti-sludge agents for shielding methods, concrete admixtures, civil engineering and building materials such as gaskets and packing, sealing materials for electronic devices such as optical fibers, waterproof materials for communication cables Used in a wide range of fields, including electrical equipment materials such as inkjet recording paper, coagulants for sludge, dewatering of gasoline and oils, water treatment agents such as water removers, printing pastes, water-swellable toys, and artificial snow. Have been. In addition, it is expected to be used for sustained-release fertilizers, sustained-release pesticides, sustained-release drugs, and the like by utilizing the sustained-release properties of the chemicals. 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:
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 product of a cationic monomer (US Pat.
No. 06717), a crosslinked isobutylene-maleic anhydride copolymer (US Pat. No. 4,389,513) and the like are known. However, since these water-absorbent resin compositions do not have decomposability, disposal after use is a problem. Currently,
At the time of disposal, these water-absorbent resins are incinerated and landfilled.However, in the incinerator method, in addition to damage to furnace materials due to heat generated during incineration, global warming It is pointed out that it causes acid rain. In addition, the method of landfill processing has the problems that the volume of plastic is bulky, the ground does not stabilize because it does not rot, and there is a major problem that the place suitable for 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). However, although such layers are said to have low toxicity per se, they are not found in nature at all, and the effects on ecosystems of long-term accumulation of these resins in soil are unknown. , Need to be thoroughly 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. Furthermore, these polymerization resins use monomers that are highly toxic to human skin, etc., and many studies have been made to remove them from products after polymerization. It is difficult. 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, for example, a polyethylene oxide crosslinked product (JP-A-6-15779).
No. 5, etc.), cross-linked polyvinyl alcohol, cross-linked carboxymethyl cellulose (US Pat. No. 4,650,716),
Alginic acid crosslinked products, starch crosslinked products, polyamino acid crosslinked products, and the like are known. Among these, crosslinked polyethylene oxide and crosslinked polyvinyl alcohol can be biodegraded only by special bacteria, so that biodegradability is slow or not decomposed at all under general conditions. Further, when the molecular weight is further increased, the decomposability is extremely lowered or the composition becomes non-decomposable. . In addition, 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. It cannot be opened widely and its absorption capacity is not high.

[Technical Background of Polyamino Acid Diameter-Based Water-Absorbent Resin] On the other hand, a resin obtained by crosslinking a polyamino acid is biodegradable and thus is friendly to the global environment. It is a material that is easy on humans because it has been shown that it is digested and absorbed, and that it does not show antigenicity in vivo and that degradation products have no toxicity. As a description example of such a resin, a method of producing a resin having a high water absorbing ability by irradiating poly-γ-glutamic acid with γ-ray is described (Kunioka et al.
0, 10, p. 755 (1993)). However, from an industrial point of view, the ⁶⁰ Co irradiation equipment used for this technology is:
In order to shut off radioactivity, large-scale equipment is required, and it is not practical because sufficient care must be taken for its management. Another problem is that polyglutamic acid as a starting material is expensive. Further, it has been reported that a cross-linked 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;
No. 43). However, in all cases, these resins were not practical because of insufficient water absorption. Therefore, the present inventors have invented a water-absorbing resin having a high salt water-absorbing ability in JP-A-7-224163. In addition, Japanese Patent Application No. Hei 9-1699
No. 1 has invented a water-absorbing resin having excellent water-absorbing ability even for salt solutions containing polyvalent ions and having excellent stability over time of the gel. However, these resins all have a carboxylic acid or a salt thereof as a functional group, and as a principle of water absorption, use the difference in osmotic pressure between intra- and extra-molecular to absorb water. Happens. In addition, when used as a thickener or the like, when used at a low pH containing natural components and the like, the water absorption was significantly reduced. Also, a method for obtaining a hydrogel by crosslinking an acidic amino acid has been reported (Akamatsu et al., US Pat. No. 3,948,863; Japanese Patent Publication No. 52-41309, Iwatsuki et al., JP-A-5-279416).
issue). However, when using this method, the polymer must react under severe conditions because of low reactivity between the polymer and the crosslinking agent, and the polymer and the precursor that can be a pendant group.
The resulting resin, where control of the reaction was almost impossible, did not perform well. In other words, it has biodegradability, and there is little change in water absorption even for salt solutions,
There is a high demand for a water-absorbing resin that can be used in a wide pH range, and there has been a demand for a resin with even higher performance.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the conventional problems as described above, have biodegradability, have a small change in water absorption even with salt solutions, and have a wide pH range.
The present invention relates to a polymer that can be used in the above range and a method for producing the polymer.

[0008]

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 matters described in the following [1] to [15].

[1] A crosslinked polymer having a repeating unit represented by the formula (1) in the molecule.

[0010]

Embedded image (Where R, -X-, R 'and n are as follows: R is a pendant group having at least one nonionic polar group; -X- is -NH-, -NR '
—, —O—, or —S—. R ′ is an alkyl group, an aralkyl group, or an aryl group. n is 1 or 2
It is. )

[2] When the nonionic polar group is —NR ₁ ″
The polymer according to [1], which is at least one selected from the group consisting of R ₂ ″, —CONR ₁ ″ R ₂ ″, and —SR ₁ ″. (Here, R ₁ ″ and R ₂ ″ are hydrogen, an alkyl group, an aralkyl group, or an aryl group.) [3] The nonionic polar group is a polyether group [1]
The polymer described in 1. [4] The repeating unit represented by the formula (1)
The polymer according to any one of [1] to [3], which contains the polymer in an amount of from 9 to 99.8%.

[0012]

Embedded image (Where R, -X-, R 'and n are as follows: R is a pendant group having at least one nonionic polar group; -X- is -NH-, -NR '
—, —O—, or —S—. R ′ is an alkyl group, an aralkyl group, or an aryl group. n is 1 or 2
It is. [5] A repeating unit represented by the formula (1)
The polymer according to any one of [1] to [4], containing 90 to 99.8%.

[0013]

Embedded image (Where R, -X-, R 'and n are as follows: R is a pendant group having at least one nonionic polar group; -X- is -NH-, -NR '
—, —O—, or —S—. R ′ is an alkyl group, an aralkyl group, or an aryl group. n is 1 or 2
It is. [6] The polymer according to any one of [1] to [5], wherein n is 1. [7] The polymer according to any one of [1] to [6], wherein -X- is -NH-. [8] A crosslinked polysuccinimide is provided with at least one compound selected from the group consisting of amines, alcohols and thiols having at least one nonionic polar group,
Wherein the compound of the formula (1)
1] A method for producing a crosslinked polymer having a repeating unit represented by [1].

[0014]

Embedded image (Where R, -X-, R 'and n are as follows: R is a pendant group having at least one nonionic polar group; -X- is -NH-, -NR '
—, —O—, or —S—. R ′ is an alkyl group, an aralkyl group, or an aryl group. n is 1 or 2
It is. [9] The crosslinked acidic polyamino acid is reacted with at least one compound selected from the group consisting of amines, thiols, and alcohols having at least one nonionic polar group by dehydration-condensation. A method for producing a crosslinked polymer having a repeating unit represented by the formula (1) in the molecule.

[0015]

Embedded image (Where R, -X-, R 'and n are as follows: R is a pendant group having at least one nonionic polar group; -X- is -NH-, -NR '
—, —O—, or —S—. R ′ is an alkyl group, an aralkyl group, or an aryl group. n is 1 or 2
It is. )

[10] When the nonionic polar group is —NR ₁ ″
The method according to [8] or [9], wherein the polymer is at least one selected from the group consisting of R ₂ ″, —CONR ₁ ″ R ₂ ″, and —SR ₁ ″. (Where R ₁ ″ and R ₂ ″
Is hydrogen, an alkyl group, an aralkyl group, or an aryl group. [11] The nonionic polar group is a polyether group,
The method for producing a polymer according to [8] or [9]. [12] The method for producing a polymer according to any one of [8] to [11], comprising 5 to 99.8% of the repeating unit represented by the formula (1) [formula 13].

[0017]

Embedded image (Where R, -X-, R 'and n are as follows: R is a pendant group having at least one nonionic polar group; -X- is -NH-, -NR '
—, —O—, or —S—. R ′ is an alkyl group, an aralkyl group, or an aryl group. n is 1 or 2
It is. [13] The polymer according to any one of [8] to [12], containing 90 to 99.8% of the repeating unit represented by the formula (1) [formula 14].

[0018]

Embedded image (Where R, -X-, R 'and n are as follows: R is a pendant group having at least one nonionic polar group; -X- is -NH-, -NR '
—, —O—, or —S—. R ′ is an alkyl group, an aralkyl group, or an aryl group. n is 1 or 2
It is. [14] The method for producing a polymer according to any one of [8] to [13], wherein n is 1. [15] The method for producing a polymer according to any one of [8] to [14], wherein -X- is -NH-.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The polymer in the present invention is an acidic polyamino acid,
Or a copolymer thereof. There are polyglutamic acid and polyaspartic acid as acidic polyamino acids,
The following description focuses on a more useful polyaspartic acid-based polymer as the water-absorbing resin.

(1) Structure of Polymer The polymer of the present invention is roughly composed of a polymer basic skeleton, a side chain portion, and a cross-linked portion of the polymer. Hereinafter, these will be described in three parts. (1-1) Polymer Basic Skeleton of Polymer The polymer basic skeleton of the polymer of the present invention is an acidic polyamino acid such as polyglutamic acid or polyaspartic acid, and thus forms a main chain with glutamic acid or aspartic acid as a repeating unit. . These may contain another amino acid as a repeating unit. Specific examples of amino acid components other than glutamic acid or aspartic acid as a copolymer include, for example, 20 kinds of essential amino acids, L-ornithine, a series of α-amino acids, β-alanine, γ-aminobutyric acid, and neutral amino acids. Acidic amino acids, ω-esters of acidic amino acids, basic amino acids, N-substituted basic amino acids, amino acids and amino acid derivatives such as aspartic acid-L-phenylalanine dimer (aspartame), and aminosulfones such as L-cysteic acid Acids and the like can be mentioned. The α-amino acid is an optically active form (L
, D-form) or a racemic form.

[0021] The polymer may be a copolymer containing a repeating unit other than an amino acid. Examples of the repeating unit of the copolymer include dehydration condensates such as aminocarboxylic acid, aminosulfonic acid, aminophosphonic acid, hydroxycarboxylic acid, mercaptocarboxylic acid, mercaptosulfonic acid, and mercaptophosphonic acid. In addition, polyamines, polyhydric alcohols, polythiols, polycarboxylic acids, polysulfonic acids, polyphosphonic acids, polyhydrazine compounds, polycarbamoyl compounds, polysulfonamide compounds, polyphosphonamide compounds , Polyvalent epoxy compounds, polyvalent isocyanate compounds, polyvalent isothiocyanate compounds, polyvalent aziridine compounds, polyvalent carbamate compounds, polyvalent carbamic acid compounds, polyvalent oxazoline compounds, polyvalent reactive unsaturated bond compounds, Examples include dehydration condensates, adducts, and substitution products of valent metals. When it is a copolymer, it may be a block copolymer or a random copolymer. Also, it may be a graft. Among these, it is preferable to use polyaspartic acid and polyglutamic acid having high water absorbency as the basic skeleton, and polyaspartic acid suitable for industrial production is particularly preferable.

As the basic polymer skeleton of the polymer of the present invention, in the case of polyaspartic acid, the amide bond in the main chain may be an α bond or a β bond. In the case of polyglutamic acid, the amide bond in the main chain may be an α bond or a γ bond. That is, in the case of polyaspartic acid and its copolymer, when the amino group of the aspartic acid or the copolymer monomer and the carboxyl group at the α-position of aspartic acid are bonded, the α-bond is formed. The case where it is bonded to the β-carboxyl group is a β bond. In the case of polyglutamic acid and a copolymer thereof, the amino group of glutamic acid or a copolymer monomer and the α of glutamic acid
Α-bond when bonded to the carboxyl group at the position, and γ when bonded to the carboxyl group at the γ-position of glutamic acid.
It is a union. Α-bond and β-bond in the case of polyaspartic acid, α-bond and γ-bond in the case of polyglutamic acid,
Usually, they are mixed. The binding mode is not particularly limited. The side chain group and the cross-linking group of the present invention are basically carboxylic acid derivatives in which the carboxyl group of the acidic polyamino acid is substituted. The details will be described below.

(1-2) Side chain structure of the polymer The polymer of the present invention is characterized in that at least one nonionic polar group is contained in the side chain portion of the polymer. The side chain of the polymer in the present invention has a structure in which a carboxyl group of an acidic polyamino acid as a polymer main chain is derived. In the present invention, the part excluding the above-mentioned bond with the polymer main chain from the side chain part of the polymer is called a pendant group. The pendant group of the polymer of the present invention is bonded to the carbonyl group of the polymer main chain by N, O, S. That is,
Amide, ester, and thioester bonds. In the case of an aspartic acid residue, the side chain group of the polymer of the present invention may be substituted at the α-position or β-position with respect to the amide bond of the polymer main chain, and may be substituted with glutamic acid. In the case of a residue, it may be substituted at the α-position or at the γ-position. One of the features of the present invention resides in that a nonionic polar group is included in the side chain group. Examples of the nonionic polar group contained in the pendant group of the present invention include the following specific examples.

[0024]

Embedded image Here, R ₁ "R ₂ ", an alkyl group, an aralkyl, or
An aryl group.

Specific examples of the nonionic polar group include:
Hydroxyl, mercapto, amino, methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, heptylamino, octylamino, nonylamino, decylamino, undecylamino , Dodecylamino, tridecylamino, tetradecylamino, pentadecylamino, hexadecylamino, heptyldecylamino, octyldecylamino, and other secondary amino groups, dimethylamino, diethylamino, dipropyl Amino group,
Dibutylamino, dipentylamino, dihexylamino, diheptylamino, dioctylamino, dinonylamino, didecylamino, diundecylamino, didodecylamino, ditridecylamino, ditetradecylamino, dipenta Tertiary amino groups such as decylamino group, dihexadecylamino group, diheptyldecylamino group, dioctyldecylamino group, ethylmethylamino group, methylpropylamino group, methoxy group, ethoxy group, propoxy group, butoxy group, pentyl Oxy, hexyloxy, heptyloxy, octyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy, tetradecyloxy, pentadecyloxy, hexadecyloxy, heptyldecyloxy , An alkoxy group such as octyldecyloxy group, an aralkyloxy group such as a phenoxy group, a benzyloxy group, a tolyloxy group, a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, and a nonylthio group. Group, decylthio group, undecylthio group,
Alkylthio groups such as dodecylthio group, tridecylthio group, tetradecylthio group, pentadecylthio group, hexadecylthio group, heptyldecylthio group, octyldecylthio group, arylthio groups such as phenylthio group, tolylthio group, and aralkylthio groups such as benzylthio group , Methyloxycarbonyl, ethyloxycarbonyl, propyloxycarbonyl, butyloxycarbonyl, pentyloxycarbonyl, hexyloxycarbonyl, heptyloxycarbonyl, octyloxycarbonyl, nonyloxycarbonyl, decyloxycarbonyl , Undecyloxycarbonyl group, dodecyloxycarbonyl group, tridecyloxycarbonyl group,
Alkyloxycarbonyl groups such as tetradecyloxycarbonyl group, pentadecyloxycarbonyl group, hexadecyloxycarbonyl group, heptyldecyloxycarbonyl group, octyldecyloxycarbonyl group, methylcarbonyloxy group, ethylcarbonyloxy group, and propylcarbonyloxy group , Butylcarbonyloxy group,
Pentylcarbonyloxy, hexylcarbonyloxy, heptylcarbonyloxy, octylcarbonyloxy, nonylcarbonyloxy, decylcarbonyloxy, undecylcarbonyloxy, dodecylcarbonyloxy, tridecylcarbonyloxy, tetradecylcarbonyl Oxy group, pentadecylcarbonyloxy group, hexadecylcarbonyloxy group,
And an alkylcarbonyloxy group such as a heptyldecylcarbonyloxy group and an octyldecylcarbonyloxy group.

Of these, a substituent having a small molecular weight and a high hydrophilicity is preferred. For example, hydroxyl group, mercapto group, amino group, methylamino group, ethylamino group, propylamino group, secondary amino group such as butylamino group, dimethylamino group, diethylamino group, dipropylamino group, dibutylamino group and the like Secondary amino group, methoxy group,
Alkoxy groups such as ethoxy group, propoxy group and butoxy group, alkylthio groups such as methylthio group, ethylthio group, propylthio group and butylthio group, methyloxycarbonyl group, ethyloxycarbonyl group, propyloxycarbonyl group and butyloxycarbonyl group Preferred are alkylcarbonyloxy groups such as an alkyloxycarbonyl group, a methylcarbonyloxy group, an ethylcarbonyloxy group, a propylcarbonyloxy group, and a butylcarbonyloxy group. Particularly, hydroxyl group, mercapto group, amino group,
Preferred are secondary amino groups such as methylamino group, ethylamino group and propylamino group, and tertiary amino groups such as dimethylamino group, diethylamino group and dipropylamino group.

The pendant group of the polymer of the present invention has at least one nonionic polar group, but the portion other than the nonionic polar group is mainly composed of carbon and hydrogen. Is called a hydrocarbon group. Examples of the hydrocarbon group of the present invention include, but are not limited to, alkyl, aralkyl, alkyl ether, phenyl, and naphthyl groups. These may be linear or branched,
It may be a ring structure. In the hydrocarbon group of the present invention, a part of the carbon may be substituted with a functional group containing O, N, S, P, B, Si or the like. That is, in the case of a ring structure, a part of carbon atoms may be substituted with O, N, S, P, B, Si, or the like, and O, N, S, P, B,
Ether group, ester group, carbonyl group, urea group, thioester group, thiocarbonyl group, sulfone group, sulfonyl group, sulfonamide group, secondary amino group, tertiary amino group, amide group, phosphone derived from Si etc. And a functional group such as a phosphonamide group may be substituted. Further, the substitution position of the nonionic polar group with respect to these hydrocarbon groups is not particularly limited.

Specific examples thereof include a hydrocarbon group in which a nonionic polar group is substituted with hydrogen for convenience. For example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group,
Hexadecyl group, heptadecyl group, alkyl group such as octadecyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group,
Cycloalkyl group such as cyclooctyl group, benzyl group,
Phenylethyl group, phenylpropyl group, aralkyl group such as phenylbutyl group, phenyl group, tolyl group, xylyl group, chlorophenyl group, phenyl group such as biphenyl group, naphthyl group, aryl group such as methylnaphthyl group, methoxyethyl group, Ethoxyethyl group, propoxyethyl group, butoxyethyl group, pentyloxyethyl group, hexyloxyethyl group, heptyloxyethyl group, octyloxyethyl group, decyloxyethyl group, undecyloxyethyl group, dodecyloxyethyl group, tridecyl Oxyethyl group, tetradecyloxyethyl group, pentadecyloxyethyl group, hexadecyloxyethyl group,
Alkoxyalkyl groups such as heptyldecyloxyethyl group and octyldecyloxyethyl group, polyoxyalkylene groups such as polyoxyethylene group and polyoxypropylene group, aryloxyalkyl groups such as phenoxyethyl group, benzyloxyethyl group, tolyloxy Aralkyloxyalkyl groups such as ethyl group, methylthioethyl group,
Ethylthioethyl group, propylthioethyl group, butylthioethyl group, pentylthioethyl group, hexylthioethyl group, heptylthioethyl group, octylthioethyl group,
Nonylthioethyl, decylthioethyl, undecylthioethyl, dodecylthioethyl, tridecylthioethyl, tetradecylthioethyl, pentadecylthioethyl, hexadecylthioethyl, heptyldecylthioethyl Alkylthioalkyl groups such as octyldecylthioethyl group, polythioethylene groups, polythioalkylene groups such as polythiopropylene groups, phenylthioethyl groups, arylthioalkyl groups such as tolylthioethyl groups, benzylthioethyl groups etc. Aralkylthioalkyl group, methylaminoethyl group, ethylaminoethyl group, propylaminoethyl group, butylaminoethyl group, pentylaminoethyl group, hexylaminoethyl group, heptylaminoethyl group, octylaminoethyl group, nonylaminoethyl group, Desi Aminoethyl, undecylaminoethyl, dodecylaminoethyl, tridecylaminoethyl, tetradecylaminoethyl, pentadecylaminoethyl, hexadecylaminoethyl, heptyldecylaminoethyl, octyldecylaminoethyl Alkylaminoalkyl, dimethylaminoethyl, diethylaminoethyl, dipropylaminoethyl, dibutylaminoethyl, dipentylaminoethyl, dihexylaminoethyl, diheptylaminoethyl, dioctylaminoethyl, dinonyl Aminoethyl group, didecylaminoethyl group, diundecylaminoethyl group, didodecylaminoethyl group, ditridecylaminoethyl group, ditetradecylaminoethyl group, dipentadecylaminoethyl group, dihexa Dialkylaminoalkyl groups such as silaminoethyl group, diheptyldecylaminoethyl group, dioctyldecylaminoethyl group, ethylmethylaminoethyl group, methylpropylaminoethyl group, trimethylammonio group, triethylammonio group, tripropylammonio Group, tributylammonio group, tripentylammonio group, dimethylethylammonio group, dimethylbenzylammonio group, trialkylammonium group such as methyldibenzylammonio group, methyloxycarbonylethyl group, ethyloxycarbonylethyl group, Propyloxycarbonylethyl group, butyloxycarbonylethyl group, pentyloxycarbonylethyl group, hexyloxycarbonylethyl group, heptyloxycarbonylethyl group, octyloxycarbo Nylethyl group, nonyloxycarbonylethyl group, decyloxycarbonylethyl group, undecyloxycarbonylethyl group, dodecyloxycarbonylethyl group, tridecyloxycarbonylethyl group, tetradecyloxycarbonylethyl group, pentadecyloxycarbonylethyl group, hexa Alkyloxycarbonylalkyl groups such as decyloxycarbonylethyl group, heptyldecyloxycarbonylethyl group, octyldecyloxycarbonylethyl group, methylcarbonyloxyethyl group, ethylcarbonyloxyethyl group, propylcarbonyloxyethyl group, butylcarbonyloxyethyl group , Pentylcarbonyloxyethyl group, hexylcarbonyloxyethyl group, heptylcarbonyloxyethyl group, octylcarbonyl Xyethyl group, nonylcarbonyloxyethyl group, decylcarbonyloxyethyl group, undecylcarbonyloxyethyl group, dodecylcarbonyloxyethyl group, tridecylcarbonyloxyethyl group, tetradecylcarbonyloxyethyl group, pentadecylcarbonyloxyethyl group, hexa And alkylcarbonyloxyalkyl groups such as a decylcarbonyloxyethyl group, a heptyldecylcarbonyloxyethyl group, and an octyldecylcarbonyloxyethyl group.
In addition, the following specific examples are given.

[0029]

Embedded image The actual structure is a structure in which hydrogen of these hydrocarbon groups is substituted with a nonionic polar group.

The hydrocarbon group constituting the pendant group of the polymer of the present invention may be unsubstituted or substituted. Examples of the substituent of the hydrocarbon group constituting the pendant group include an alkyl group having 1 to 18 carbon atoms which may be branched, and a carbon atom having 3 carbon atoms.
To 8 cycloalkyl groups, aralkyl groups, optionally substituted phenyl groups, optionally substituted naphthyl groups,
An optionally branched alkoxy group having 1 to 18 carbon atoms,
Aralkyloxy group, phenylthio group, carbon number 1 to 1
An optionally branched alkylthio group having 8 carbon atoms, an optionally branched alkylamino group having 1 to 18 carbon atoms,
To 18 dialkylamino groups which may be branched, trialkylammonio groups which may have 1 to 18 carbon atoms, a hydroxyl group, an amino group, a mercapto group, a cationic group, a sulfonic acid group, a phosphonic acid group and These include salts, alkoxycarbonyl groups, alkylcarbonyloxy groups and the like.

The polymer of the present invention may contain another side chain group in addition to the pendant group containing a nonionic polar group. For example, there are a group having a carboxyl group in a structure in which an imide ring is simply opened, an amino acid residue such as lysine, a pendant group having a carboxyl group, and a pendant group having a sulfonic acid group. Here, in the case of a carboxyl group or a sulfonic acid group, a salt may be used. Examples of the counter ion of the carboxyl group include alkali metal salts, ammonium salts, and amine salts. Here, when an ionic functional group is contained, the amount of water absorption and the thickening effect with respect to water containing no salt are large, but are small with respect to an aqueous solution containing salt. On the other hand, when the ionic substituent is eliminated, and when completely non-ionic, the reduction in water absorption and the decrease in the thickening effect are reduced for an aqueous solution containing a salt, but the water absorption for a salt-free water and The thickening effect is small. That is, the amount of the ionic functional group may be selected depending on the salt concentration of the aqueous solution intended for the intended use. Conversely, by adjusting the amount of ionic and nonionic functional groups, it is possible to cope with various salt aqueous solutions.

For the above reasons, the amount of the pendant group of the present invention is not particularly limited, and may be determined according to the intended use. Generally, as monomer units to the whole polymer, 5 to 99.8 mol% is preferable, and 20 to 99.8 mol% is more preferable. When used in low pH, high salt water, etc., as a monomer unit to the whole polymer,
30 to 99.8 mol% is preferable, and 50 to 99.8 mol% is more preferable. The substitution position of these pendant groups is not particularly limited.

The hydrocarbon group which may contain O, N and S constituting the pendant group may be unsubstituted or substituted with a functional group other than those described above. Examples of the substituent of the hydrocarbon group which may contain O, N, and S constituting the pendant group include an alkyl group which may have 1 to 18 carbon atoms and may be branched, a cycloalkyl group having 3 to 8 carbon atoms, An aralkyl group, an optionally substituted phenyl group, an optionally substituted naphthyl group, an optionally branched trialkylammonio group having 1 to 18 carbon atoms, a cationic group, a sulfone group,
Examples include a phosphone group and salts thereof. Specific examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl,
Alkyl groups such as tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptyldecyl group, octyldecyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group,
Cycloalkyl group such as cyclooctyl group, benzyl group,
Aralkyl groups such as phenylethyl group, phenylpropyl group and phenylbutyl group, phenyl group such as phenyl group, tolyl group, xylyl group, chlorophenyl group and biphenyl group, naphthyl group such as naphthyl group and methylnaphthyl group, cationic group and sulfone Groups, phosphon groups and salts thereof, and the like. Here, when an ionic functional group is contained as a substituent, the amount of water absorption and the effect of increasing the viscosity with respect to water containing no salt are increased, but are reduced with respect to an aqueous solution containing salt. On the other hand, when the ionic substituent is eliminated, and when completely non-ionic, the reduction in water absorption and the decrease in the thickening effect are reduced for an aqueous solution containing a salt, but the water absorption for a salt-free water and The thickening effect is small. That is, the amount of the ionic functional group may be selected depending on the salt concentration of the aqueous solution intended for the intended use. Conversely, by adjusting the amount of ionic and nonionic functional groups, it is possible to cope with various salt aqueous solutions.

In addition, when the molecular weight of the crosslinking group increases, the molecular weight per monomer unit relatively increases.
The smaller the molecular weight of the cross-linking group is, the better the water absorption per unit weight becomes. Further, those having a simple production method are preferable. Of these, unsubstituted, methyl, ethyl, methoxy, methyloxycarbonyl, methylcarbonyloxy, hydroxyl, amino, mercapto, carboxyl, sulfone, phosphonic acid groups and salts thereof are preferred. Further, as the water retention agent, a polar group is more preferable, and therefore, unsubstituted, hydroxyl, amino, mercapto, carboxyl, sulfonic, phosphonic, and salts thereof are particularly preferable. Further, when used for low pH and high concentration salt water, non-ionic groups such as unsubstituted hydroxyl groups, amino groups and mercapto groups are preferred. Here, the amount of the crosslinked portion is not particularly limited, but is preferably 0.1 to 20 mol% as a monomer unit with respect to the entire polymer, and is preferably 0.5 to 20 mol%.
-10 mol% is more preferred.

(2) Method for Producing Polymer The method for producing the polymer of the present invention is not particularly limited, but here, a description will be given mainly of a more useful polyaspartic acid-based polymer as a water-absorbing resin. The production of the polyaspartic acid polymer of the present invention is characterized by using polysuccinimide, polyaspartic acid, polyaspartic acid ester, or a copolymer thereof.

(2-1) Method for Producing Polysuccinimide A method for producing a polyaspartic acid-based polymer is not particularly limited. These methods suitable for performing industrial production will be described. The method for producing the polysuccinimide is not particularly limited, but is described in Journal of American Chemical Society (J. Amer. Chem. So).
c. ), Vol. 80, pp. 3361-(1958). The molecular weight of the polysuccinimide used is not particularly limited, but the higher the molecular weight, the higher the capacity as a water retention material. Generally, 30,000 or more, preferably 60,000 or more, more preferably 9
More than ten thousand. During the production of the polysuccinimide of the present invention, a copolymer can be produced by adding an amino acid other than aspartic acid. Specific examples of amino acid components other than aspartic acid include, for example, 20 kinds of essential amino acids, L-ornithine, a series of α-amino acids, β-
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. In addition, a copolymer can be produced by adding a monomer component other than an amino acid to the polymer.

Examples of the monomer components added during the production of the copolymer include aminocarboxylic acid, aminosulfonic acid, aminophosphonic acid, hydroxycarboxylic acid, mercaptocarboxylic acid, mercaptosulfonic acid, and mercaptophosphonic acid. . Also, polyamines, polyhydric alcohols,
Polyvalent thiol, polycarboxylic acid, polysulfonic acid, polyphosphonic acid, polyhydrazine compound, polycarbamoyl compound, polysulfonamide compound, polyphosphonamide compound, polyepoxy compound, polyisocyanate Examples include compounds, polyvalent isothiocyanate compounds, polyvalent aziridine compounds, polyvalent carbamate compounds, polyvalent carbamic acid compounds, polyvalent oxazoline compounds, polyvalent reactive unsaturated bond compounds, and polyvalent metals. A crosslinked polymer is produced using the polysuccinimide thus obtained, polyaspartic acid obtained by hydrolyzing the polysuccinimide, and polyaspartic acid ester as a derivative.

(3) Method for Producing Cross-Linked Polymer The reactions in the production of the polymer of the present invention, except for the order, are basically three steps: a cross-linking reaction, a pendant group introduction reaction, and a nonionic polar group introduction reaction. is there. Other reactions may be used or may be used in combination. The production method varies depending on the order in which these three reactions are performed. Although the method is not particularly limited, examples thereof will be described below. (A) A method of introducing a pendant group containing a non-ionic polar group after or simultaneously with crosslinking the polysuccinimide (B) Precursor of the non-ionic polar group after crosslinking or simultaneously with the polysuccinimide (C) A method of introducing a pendant group containing a nonionic polar group into a polysuccinimide, followed by crosslinking (D) Polysuccinic acid A method of introducing a pendant group which can be a precursor of a nonionic polar group into an imide, followed by crosslinking and further substitution with a nonionic polar group (E) After crosslinking an acidic polyamino acid or an ester thereof, or Simultaneously, a method of introducing a pendant group containing a nonionic polar group (F) after crosslinking an acidic polyamino acid or an ester thereof, or A method of introducing a pendant group which can be a precursor of a nonionic polar group into the acidic polyamino acid or an ester thereof to which a pendant group containing a nonionic polar group is introduced. Then, a method of crosslinking (H) A method of introducing a pendant group which can be a precursor of a nonionic polar group into an acidic polyamino acid or an ester thereof and substituting the ionic group with a nonionic polar group, followed by a method of crosslinking (I) A method of polymerizing an acidic amino acid substituted with a pendant group containing an ionic polar group, an unsubstituted acidic amino acid and / or an acidic amino acid oligomer in the presence of a crosslinking agent (J) A pendant group which can be a precursor of a nonionic polar group Substituted acidic amino acids, unsubstituted acidic amino acids and / or
Alternatively, a method of polymerizing in the presence of an acidic amino acid oligomer and a cross-linking agent and substituting with a nonionic polar group Among these methods, the methods (I) and (J) involve a method in which the obtained resin does not have a very high molecular weight. It is not preferable in the field where the water absorption is not high and high water absorption is required. In addition, protection of the nonionic polar group is required, and the process becomes complicated. On the other hand, the methods (A) to (H) are preferable because the water absorption and gel required for the water-absorbing resin can be adjusted and a resin having a high water absorption can be obtained. In this,
The methods (A) to (D) are more preferable because the reaction can be performed under mild conditions. Further, in these methods, it is preferable to carry out the crosslinking reaction first. The reason will be described below.

That is, when the polymer of the present invention is used as a water-absorbing resin, the degree of the crosslinking reaction (hereinafter referred to as the degree of cross-linking) changes the water-absorbing properties of the produced resin. In order to obtain, it is necessary to strictly control the crosslinking reaction. However, if the pendant group introduction reaction is performed first and the pendant group is introduced into the polymer main chain, the reaction kinetics often decrease due to the decrease in the number of reaction points, and it becomes difficult to control the degree of crosslinking. Therefore,
It is preferable to carry out the crosslinking reaction first to control the degree of crosslinking.

In these reactions, although there is a difference whether the reaction system is a homogeneous system or a heterogeneous system, basic reactions are used in a crosslinking reaction, a pendant group introduction reaction, and a substitution reaction with a nonionic polar group. Since the typical reaction conditions are almost the same, each reaction will be described individually.

When the cross-linking reaction is performed first, it is insolubilized by the cross-linking, so that the subsequent reaction often becomes a heterogeneous system. In the case of a heterogeneous reaction, the reaction rate may be lower than that of a homogeneous reaction.However, a method used for an existing heterogeneous system, such as increasing the stirring efficiency or using a phase transfer catalyst, may be used. You may use it. In addition, when the reaction is performed in a gel state, the reaction is slower than the reaction in a solution state, but the substance in the gel can be moved in and out of a normal liquid-solid phase two-phase reaction. Therefore, the reaction becomes faster. In this case, the reaction may be in the form of a liquid-solid phase two-phase system or a gel may be formed during the reaction.

Hereinafter, these production methods will be described, but mainly the (A) and (B) suitable as industrial production methods. The method for producing the crosslinked polymer is not limited to the methods (A) and (B), but may be any of (C) to (J).
And other methods can also be used. The description will be made on three kinds of reactions: a crosslinking reaction, a pendant group introduction reaction, and a substitution reaction with a nonionic polar group.

(4) Crosslinking Reaction The crosslinking reaction of the polymer of the present invention is not particularly limited, but includes the following three types. (4-1) Method for crosslinking polysuccinimide (4-2) Method for crosslinking acidic polyamino acid (4-3) Method for crosslinking acidic polyamino acid ester Among these, the number of steps is small and mild. A method that can efficiently react under the conditions is preferable, and a method of reacting a polysuccinimide with a crosslinking agent such as a polyvalent amine is particularly preferable. Alternatively, crosslinking may be performed by using a crosslinking agent having a reactive group having different reactivity to cause a stepwise reaction.

The crosslinking agent used in the crosslinking reaction of the present invention includes polyvalent amines, polythiols, polyhydric alcohols and the like. The reaction between the polysuccinimide and the crosslinking agent is not particularly limited as long as it is a polyfunctional compound that reacts with the imide ring of the polysuccinimide, and examples thereof include a polyamine and a polythiol. In general, hydrazine, ethylenediamine, propylenediamine, 1,4-butanediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tetradecamine Methylenediamine, hexadecamethylenediamine, 1-amino-
Aliphatic polyamines such as 2,2-bis (aminomethyl) butane, tetraaminomethane, diethylenetriamine and triethylenetetramine, norbornenediamine, 1,4
Alicyclic polyamines such as diaminocyclohexane, 1,3,5-triaminocyclohexane and isophoronediamine; aromatic polyamines such as phenylenediamine, tolylenediamine and xylylenediamine; basicity represented by lysine and ornithine Polyamines such as amino acids or their esters, monoamino compounds such as cystamine bonded by disulfide bonds and derivatives thereof, 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 1,6 -Hexanedithiol, aliphatic polythiol such as pentaerythrithiol, alicyclic polythiol such as cyclohexanedithiol, xylylenedithiol, benzenedithiol,
Aromatic polythiols such as toluenedithiol, trimethylolpropane tris (thioglycolate), trimethylolpropane tris (3-mercaptopropionate) pentaerythritol tetrakis (thioglycolate), pentaerythritol tetrakis (3-mercaptopropionate) Esters such as polythiol are exemplified. Among them, preferred are ethylenediamine, propylenediamine, 1,4-butanediamine, which have low odor and high reactivity with the imide ring of polysuccinimide,
Heptamethylenediamine, hexamethylenediamine, lysine, ornithine and cystamine are preferred.

The amount of the crosslinking agent used depends on the functional number of the crosslinking agent,
It depends on the degree of crosslinking determined by the molecular weight, but also depends on the type of application used. Here, for convenience, the degree of cross-linking is defined as expressing the distance between cross-links, the number of constituent monomers, or the degree of the ratio of cross-linked portions to the polymer main chain. The amount of use is not particularly limited, but if the degree of cross-linking is too large, the water absorption of the resin decreases, and if the degree of cross-linking is too low, the resin becomes water-soluble and does not exhibit water absorption, so it is adjusted to an appropriate degree of cross-linking. There is a need. The amount is preferably from 0.1 to 30 mol%, particularly preferably from 1 to 20 mol%, based on the monomer unit of the polysuccinimide. Further, the reaction product after the crosslinking reaction may be taken out of the system or, if necessary, may be continuously subjected to a pendant group introduction reaction or a cationization reaction as it is. Here, when the reaction product is taken out of the system, the reaction product may be dried before use.

(4-1) Method of Cross-Linking Polysuccinimide The method of cross-linking polysuccinimide is not particularly limited, but a method of reacting a cross-linking agent with polysuccinimide in an organic solvent is generally used. When cross-linking the polysuccinimide, any one capable of dissolving the polysuccinimide, or one capable of dissolving the cross-linking agent or the reactant that can be a pendant group may be used, and any of the common solvents used for chemical reactions can be used. . Similarly, in the case of polyaspartic acid and polyaspartic acid ester, those capable of dissolving a polymer or a crosslinking agent are preferable. Among these, when crosslinking polysuccinimide, those capable of dissolving polysuccinimide or a polysuccinimide derivative are preferable. For example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, N'-dimethylimidazolidinone, dimethyl sulfoxide, sulfolane and the like. Among them, N, N-dimethylformamide and N, N-dimethylacetamide, which have high solubility of polysuccinimide, are particularly preferable. These solvents may be used alone or in combination of two or more.

If necessary, a poor solvent which does not dissolve or only slightly dissolves polysuccinimide may be added for the purpose of delaying the crosslinking reaction or dispersing the raw materials or products. The poor solvent is not particularly limited, and any solvent generally used in chemical reactions can be used.

For example, water, methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, heptanol, octanol,
-Methoxyethanol, alcohols such as 2-ethoxyethanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol,
Glycols such as dipropylene glycol, glycosolves such as methyl glycosolve and ethyl glycosolve, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, cyclic ethers such as tetrahydrofuran and dioxane, petroleum ether, pentane, hexane, heptane and octane , Cyclohexane, benzene, toluene, ethylbenzene, xylene, decalin, diphenyl ether, anisole, cresol and the like.

The concentration of polysuccinimide in the crosslinking reaction is not particularly limited, but is preferably from 0.1 to 50% by weight, particularly preferably from 1 to 40% by weight.

(4-2) Method of Cross-Linking Acidic Polyamino Acid As a method of cross-linking an acidic polyamino acid, a method of dehydrating and condensing the cross-linking agent and the acidic polyamino acid is generally used. The dehydration condensation may be any of a method of removing generated water by azeotropic distillation with a solvent, a method of adding molecular sieve as a dehydrating agent, a method of reacting with a dehydrating condensing agent, and a method of using an enzyme. Further, aspartic acid and the crosslinking agent can be uniformly mixed, and the solvent can be removed, and the reaction can be performed in a solid state. Examples of the condensing agent include carbodiimides such as dicyclohexylcarbodiimide, N-ethyl-N '-(3-dimethylaminopropyl) carbodiimide, 1-acylimidazolide, 2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline. Phosphorus-containing compounds such as triphenylphosphine / carbon tetrachloride, triphenylphosphine / bromotrichloromethane, bis (2-nitrophenylester) phenylphosphonate, diethyl cyanophosphonate, and diphenylphosphoroazide;
Redox condensing agents such as 2-fluoro-1-ethylpyridium tetrafluoroborate, triphenylphosphine / bis (benzothiazole) disulfide, and tributylphosphine / bis (benzothiazole) disulfide. Examples of enzymes include lipases such as penicillin acylase and yeast lipase.
The reaction temperature during the dehydration condensation is preferably from 20 to 250 ° C,
100-180 ° C is particularly preferred.

Further, esterification from an acidic polyamino acid,
A method of amidation or thioesterification may be used. In this case, ordinary reaction conditions used in organic chemistry can be used. As the method, an acidic polyamino acid may be used as an acidic amino acid residue and reacted with its carboxyl group. Moreover, you may introduce after increasing reactivity as a derivative. For example, a method of performing a dehydration condensation reaction with a carboxyl group of an acidic amino acid residue and an alcohol, an amine or a thiol, activating a carboxyl group of an acidic amino acid residue with an acid anhydride, an acid halide, or an acid azide to activate an alcohol, an amine, A method of reacting with a thiol, a carboxyl group of an acidic amino acid residue and an activated alcohol, for example, a halide, an ester, a sulfonate, a sulfate, and an amine as a silicon derivative. Carboxyl group and epoxy compound, isocyanate compound,
Aziridine compound, a method of reacting with an alkyl metal,
There are a method in which the carboxyl group of the acidic amino acid residue is reacted with a halide or the like as a salt, and a method in which the carboxyl group of the acidic amino acid residue is converted into an active ester by transesterification or transamidation.

(4-3) Method for Cross-Linking Acidic Polyamino Acid Ester The method for cross-linking the acidic polyamino acid ester is not particularly limited, but a method in which a cross-linking agent is reacted with an acidic polyamino acid ester in an organic solvent is generally used. It is. Examples of the ester used include a small alcohol component such as methyl and ethyl, an alcohol component having an electron withdrawing group such as chloromethyl and dichloromethyl, and an alcohol such as N-hydroxysuccinimide. In some cases, a catalyst such as an acid catalyst or a base catalyst may be used. When the reaction system becomes heterogeneous or when the raw materials used are insoluble, a phase transfer catalyst may be used.

(5) Pendant group introduction reaction The method of the pendant group introduction reaction of the crosslinked polymer is not particularly limited, and the method is described below. (5-1) Method of reacting polysuccinimide with an amine containing a nonionic polar group (5-2) Method of dehydrating and condensing an acidic polyamino acid with an amine containing a nonionic polar group (5- 3) A method of transesterifying an acidic polyamino acid ester with an amine containing a nonionic polar group, and a method of introducing a pendant group containing a functional group that is a precursor of a nonionic polar group. (5-4) A method in which a pendant group which can be a precursor of a nonionic polar group is introduced into polysuccinimide and further substituted with a nonionic polar group. Among these, efficient reaction can be performed under mild conditions. The method is preferably a method in which a polysuccinimide or a derivative thereof is reacted with an amine containing a nonionic polar group, or a pendant group which can be a precursor of a nonionic polar group is introduced, and further a nonionic polar group is introduced. Is preferable.

Further, depending on the reaction conditions, the nonionic polar group itself may react with an amine or the like. That is, side chain groups are elongated. As a result, a decrease in the number of hydrophilic groups is not preferable because it leads to a decrease in water absorption. However, it is preferable when the gel strength is increased due to an increase in molecular weight. The solvent used for the pendant group introduction reaction of the crosslinked polymer may be the same as or different from the solvent used for the crosslinking reaction. Since a method of introducing a pendant group containing a nonionic polar group into a polysuccinimide and a method of introducing a pendant group containing a precursor of a nonionic polar group have a lot in common, they are described together. If the crosslinking reaction is carried out first, it is insolubilized by the crosslinking, so that the subsequent reaction often becomes a heterogeneous system. In the case of a heterogeneous reaction, the reaction rate may be lower than that of a homogeneous reaction.However, a method used for an existing heterogeneous system, such as increasing the stirring efficiency or using a phase transfer catalyst, may be used. You may use it. In addition, when the reaction is performed in a gel state, the reaction is slower than the reaction in a solution state, but the substance in the gel can be moved in and out of a normal liquid-solid phase two-phase reaction. Therefore, the reaction becomes faster. In this case, the reaction may be in the form of a liquid-solid phase two-phase system or a gel may be formed during the reaction.

The reaction reagent used for the pendant group introduction reaction may contain a nonionic polar group or may contain a precursor which can be a nonionic polar group. The reaction reagent containing a nonionic polar group used for the pendant group introduction reaction is an amine, thiol, or alcohol having at least one nonionic polar group, examples of which are given below.

[0056]

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[0057]

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As amines, thiols, and alcohols containing polyethers, H ₂ N (CH ₂ CH ₂ O) nH;
H ₂ N (CH ₂ CH ₂ CH ₂ O) nH, H ₂ N (CH ₂ CH _{2
O) m (CH 2 CH 2} CH 2 O) nH, H 2 N (CH 2 CH 2
O) nR, H ₂ N (CH ₂ CH ₂ CH ₂ O) nR, H ₂ N
(CH ₂ CH ₂ O) m (CH ₂ CH ₂ CH ₂ O) nR, H ₂ N
(CH ₂ CH ₂ O) nCOR, H ₂ N (CH ₂ CH ₂ CH)
_{2 O) nCOR, H 2 N} (CH 2 CH 2 O) m (CH 2 CH 2
CH ₂ O) nCOR the like. Here, R is an alkyl group, an aralkyl group, or an aryl group, and is not particularly limited. Also, n is not particularly limited. These may be used alone or as a mixture of two or more. Note that the pendant group introduction reaction is a multi-step system in which even if a pendant group is introduced in one step, a substituent is once introduced, and then another substituent is reacted with the substituent to form a pendant group. No problem. As a reaction reagent containing a precursor that can be a nonionic polar group used for the pendant group introduction reaction, an amine, thiol, or alcohol having at least one hydroxyl group, a halogen group, a sulfonic ester group, and a sulfate ester group can be used. An example is described in the following (6).

Although the amount of the pendant group to be used is not particularly limited, it is preferably 1 to 99.8 mol%, more preferably 10 to 99.8 mol% based on the polysuccinimide. Further, the reaction product after the pendant group introduction reaction may be taken out of the system or, if necessary, may be continuously subjected to a crosslinking reaction or a substitution reaction to a nonionic polar group as it is. Here, when the reaction product is taken out of the system, the reaction product may be dried before use. The reaction product after the pendant group introduction reaction may optionally hydrolyze a part of the imide ring. (5-1) a method of reacting a polysuccinimide with an amine containing a nonionic polar group, and (5-4) introducing a pendant group capable of serving as a precursor of a nonionic polar group into the polysuccinimide, A method of further substituting a nonionic polar group.

The solvent used for the reaction for introducing a pendant group into polysuccinimide is not particularly limited, and any solvent capable of dissolving polysuccinimide or a polysuccinimide derivative, or capable of dissolving a reactant capable of forming a pendant group. Any common solvent used in chemical reactions can be used. Among these, when a pendant group is introduced simultaneously with crosslinking, and when a pendant group is introduced before crosslinking, those capable of dissolving polysuccinimide are preferable. For example, N, N-dimethylformamide, N, N- Dimethylacetamide, N-methylpyrrolidone, N, N'-dimethylimidazolidinone, dimethylsulfoxide, sulfolane and the like are preferred.
Among them, polysuccinimide having high solubility, N, N-
Dimethylformamide and N, N-dimethylacetamide are particularly preferred.

In addition, water, methanol, ethanol, propanol, isopropanol, butanol,
Alcohols such as pentanol, hexanol, heptanol, octanol, 2-methoxyethanol and 2-ethoxyethanol, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol and dipropylene glycol, methyl glycosolve and ethyl glycosolve Such as glycosolves, 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,
Examples include toluene, ethylbenzene, xylene, decalin, diphenyl ether, anisole, and cresol. These vary depending on the structure, polarity and the like of the reaction reagent which can be a pendant group.

When the cross-linking reaction is carried out first, the cross-linked product itself is insoluble in almost all solvents, and therefore, it is preferable that the cross-linked product be capable of dissolving the reaction reagent which can be a pendant group. As the reaction solvent, the above-mentioned solvents can be used. In particular, a polar solvent is preferable because a reaction reagent containing a nonionic polar group has high polarity. Among them, water, methanol, ethanol, propanol, isopropanol, acetone and the like are preferable, and water is particularly preferable. However, when water is used, a gel is formed as the pendant group introduction reaction proceeds, and uniform stirring cannot be performed. In this case, it is preferable to use a poor solvent such as methanol, ethanol, isopropanol, or acetone mixed with water, since the swelling ratio of the gel is reduced and the stirring becomes smooth. These solvents may be used alone or in combination of two or more. In addition, in the pendant group introduction reaction, for the purpose of dispersing raw materials or products,
If necessary, a poor solvent that does not dissolve or only slightly dissolves the polysuccinimide may be added.

The poor solvent is not particularly limited, and any solvent generally used in chemical reactions can be used. For example, water, alcohols such as methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, heptanol, octanol, 2-methoxyethanol, 2-ethoxyethanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, diethanol Glycols such as propylene glycol, methyl glycosolve, glycosolves such as ethyl glycosolve, acetone, methyl ethyl ketone, ketones such as methyl isobutyl ketone,
Examples include 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. Here, whether these solvents become poor solvents or good solvents is determined not only for polysuccinimide but also for polyaspartic acid derivatives into which pendant groups have been introduced. It depends on the group.

The concentration of the polysuccinimide or the crosslinked polysuccinimide at the time of producing the polysuccinimide derivative is not particularly limited, but is preferably 0.1 to 50% by weight, particularly preferably 1 to 40% by weight. A catalyst may be used for the crosslinking reaction or the pendant group introduction reaction as necessary. Generally, a base catalyst is used as the catalyst.

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 and hydrogen carbonate. Alkali metal bicarbonates such as potassium, alkali metal acetates such as sodium acetate and potassium acetate, alkali metal salts such as sodium oxalate, inorganic reagents such as ammonia, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentyl Amine, trihexylamine, triethanolamine, tripropanolamine, tributanolamine, tripentanolamine, trihexanolamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine Emissions, dihexylamine, dicyclohexylamine, dibenzylamine, ethylmethylamine, methylpropylamine, butyl methylamine, methyl pentyl amine, methyl hexyl amine, pyridine,
Examples include amines such as picoline and quinoline.

(5-2) A method of dehydrating and condensing an acidic polyamino acid with an amine containing a nonionic polar group In the method of dehydrating and condensing an acidic polyamino acid with an amine containing a nonionic polar group, the reaction conditions are as follows. Depending on the case, the nonionic polar group itself may react with an amine or the like. That is, the side chain group is elongated, and as a result,
A decrease in the number of hydrophilic groups is not preferable because it leads to a decrease in water absorption, but is preferable when the gel strength increases due to an increase in molecular weight. In order to reduce the decrease in the hydrophilic group, a method of protecting the nonionic polar group and introducing a pendant group to the acidic polyamino acid after introducing the pendant group includes a method of dehydrating and condensing the above-mentioned reaction reagent and the acidic polyamino acid. General. The dehydration condensation may be any of a method of removing generated water by azeotropic distillation with a solvent, a method of adding molecular sieve as a dehydrating agent, a method of reacting with a dehydrating condensing agent, and a method of using an enzyme. Also,
Aspartic acid and the cross-linking agent can be uniformly mixed, and the reaction can be performed in a solid phase state in which the solvent is removed. Examples of the condensing agent include carbodiimides such as dicyclohexylcarbodiimide, N-ethyl-N ′-(3-dimethylaminopropyl) carbodiimide, 1-acylimidazolide,
Ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline, triphenylphosphine / carbon tetrachloride, triphenylphosphine / bromotrichloromethane, bis (2-nitrophenylester) phenylphosphonate, diethyl cyanophosphonate, diphenylphosphoro Examples include phosphorus-containing compounds such as azide, redox condensing agents such as 2-fluoro-1-ethylpyridium tetrafluoroborate, triphenylphosphine / bis (benzothiazole) disulfide, and tributylphosphine / bis (benzothiazole) disulfide. Examples of enzymes include lipases such as penicillin acylase and yeast lipase. The reaction temperature at the time of dehydration condensation is preferably from 20 to 250 ° C, particularly preferably from 100 to 180 ° C.

Further, esterification from an acidic polyamino acid,
A method of amidation or thioesterification may be used. In this case, ordinary reaction conditions used in organic chemistry can be used. As the method, an acidic polyamino acid may be used as an acidic amino acid residue and reacted with its carboxyl group. Moreover, you may introduce after increasing reactivity as a derivative. For example, a method of performing a dehydration condensation reaction with a carboxyl group of an acidic amino acid residue and an alcohol, an amine or a thiol, activating a carboxyl group of an acidic amino acid residue with an acid anhydride, an acid halide, or an acid azide to activate an alcohol, an amine, A method of reacting with a thiol, a carboxyl group of an acidic amino acid residue and an activated alcohol, for example, a halide, an ester, a sulfonate, a sulfate, and an amine as a silicon derivative. Carboxyl group and epoxy compound, isocyanate compound,
Aziridine compound, a method of reacting with an alkyl metal,
There are a method in which the carboxyl group of the acidic amino acid residue is reacted with a halide or the like as a salt, and a method in which the carboxyl group of the acidic amino acid residue is converted into an active ester by transesterification or transamidation.

(5-3) Method of Transesterifying Polyaspartic Acid Ester with Amines Containing Nonionic Polar Groups The method of crosslinking acidic polyamino acid esters is not particularly limited, but a crosslinking agent in an organic solvent is used. Is generally reacted with an acidic polyamino acid ester. Examples of the ester used include a small alcohol component such as methyl and ethyl, an alcohol component having an electron withdrawing group such as chloromethyl and dichloromethyl, and an alcohol such as N-hydroxysuccinimide. In some cases, a catalyst such as an acid catalyst or a base catalyst may be used. When the reaction system becomes heterogeneous or when the raw materials used are insoluble, a phase transfer catalyst may be used.

The drying temperature of the resin after completion of the crosslinking reaction and the pendant group introduction reaction is not particularly limited.
To 150 ° C, and particularly preferably 40 to 100 ° C. The method for drying these resins is not particularly limited, and may be hot air drying, drying with specific steam, microwave drying, reduced pressure drying, drum drying, drying by azeotropic dehydration in a hydrophobic organic solvent. Drying can be carried out by a known method. The drying temperature is preferably from 20 to 200C, more preferably from 50 to 120C.

The obtained resin may be subjected to surface crosslinking, if necessary.

(6) Introduction Reaction of Nonionic Polar Group The introduction reaction of the nonionic polar group of the present invention is carried out by introducing a pendant group containing a precursor of a nonionic polar group into polysuccinimide, Used to change the body to a nonionic polar group. Generally, the case where deprotection of a nonpolar group protected with a protecting group is also included. Examples of the reaction for introducing a nonionic polar group of the present invention include a hydrolysis reaction, a substitution reaction of a halogen compound, a sulfonic acid ester, a sulfate ester, and the like, and an addition reaction using an isocyanate and an epoxy compound.

(7) Shape and Particle Diameter of Crosslinked Acidic Polyamino Acid Resin The shape of the crosslinked acidic polyamino acid resin is irregularly crushed,
Various types such as a sphere, a granule, a granule, a granule, a scale, a lump, a pearl, a fine powder, a fiber, a bar, 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. The particle size of these crosslinked polyamino acid-based water-absorbing resins is not particularly limited, but varies depending on the intended use.

For example, in the case of disposable diapers, the average particle size is preferably 100 to 1000 μm, and it is desired that the gel particles do not cause a high absorption rate and gel blocking.
６００600 μm is more preferred. When it is used for kneading into a resin such as a water-stopping material, it is preferably 1 to 10 μm. In the case of a water retention material for agriculture and horticulture, it is 100 μm in consideration of dispersibility with soil.
m to 5 mm is preferred. Either one depends on the intended use.

(8) Form of Use of Crosslinked Acidic Polyamino Acid Resin The form of use of the crosslinked acidic polyamino acid resin is not particularly limited, and may be used alone or in combination with other materials. . For example, a method of kneading a thermoplastic resin and molding by injection molding or the like, after mixing a monomer of a constituent resin and an acidic polyamino acid-based resin and an initiator as necessary,
A method of polymerizing by light or heat, a method of dispersing a resin and an acidic polyamino acid-based resin in a solvent, casting and removing the solvent, a method of mixing a prepolymer and an acidic polyamino acid-based resin and then crosslinking, a method of polymer and acidic There is a method of cross-linking after mixing the polyamino acid resin, and the like. The resin composition of the present invention is not particularly limited as a molded product, and can be used as a solid, a sheet, a film, a fiber, a nonwoven fabric, a foam, a rubber, and the like. The molding method is not particularly limited.

On the other hand, the acidic polyamino acid-based resin used in the present invention may be used alone or in a complex formed by combining it with another material. Although the structure of the composite is not particularly limited, for example, a method of sandwiching between pulp and nonwoven fabric, a method of forming a sandwich structure, a method of forming a multilayer structure using a resin sheet and a film as a support, and a method of casting into a resin sheet to form a two-layer structure There are methods.

The water-absorbing resin used in the present invention may be used in combination with two or more other water-absorbing resins, if necessary. 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. Further, an oxidizing agent, an antioxidant, a reducing agent, 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 resin of the present invention 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.

(9) Use of Crosslinked Acidic Polyamino Acid Resin The use of the crosslinked acidic polyamino acid resin is not particularly limited, but it can be used for any of the conventional water absorbent resins. For example, sanitary articles, sanitary articles such as disposable diapers, breast milk pads, disposable rags, dressing materials for wound protection, medical underpads, medical supplies such as 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 products such as cut flower prolonging agents, floral foam (cutting flower fixing material), nursery beds, hydroponic cultivation, vegetation sheets, seed tape, fluid seeding, dew condensation prevention agricultural sheets, food tray freshness Food packaging materials such as holding 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, and anti-sludge agents for shielding methods Construction materials such as concrete admixtures, gaskets and packing, sealing materials for electronic devices such as optical fibers, waterproof materials for communication cables, and electrical devices such as recording paper for inkjet. Wood, sludge coagulants, gasoline,
Dehydration of oils, water treatment agents such as water removers, printing pastes, water-swelling toys, artificial snow, sustained-release fertilizers, sustained-release pesticides, sustained-release agents, humidity regulators, antistatic agents, etc. No.

[0078]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the examples. In the following Examples and Comparative Examples, “parts” means “parts by weight”. The measurement of water absorption and biodegradability in the examples were measured by the following methods.

(1) Tea Bag Method The amount of water absorption was measured for a saline solution and an aqueous solution having a different pH. That is, about 0.1 part of a water-absorbent resin is put into a non-woven tea bag (80 mm × 50 mm), immersed in an excessive solution having a predetermined concentration or pH, and allowed to swell for 1 hour. The tea bag was pulled up, drained for 1 minute, and weighed. Assuming that 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 measured value was divided by the weight of the water-absorbent resin. ).
The change in water absorption indicates the ratio of the water absorption using a 1% NaCl aqueous solution to the water absorption of distilled water in the case of a salt aqueous solution,
In the case of an aqueous solution having a changed pH, the ionic strength was represented by the ratio of the water absorption of a pH 2 aqueous solution to the water absorption of a pH 7 aqueous solution, which was adjusted using a phosphate buffer of 0.01 mol / l.

(2) Measurement of biodegradability The biodegradability was measured by a compost method. The compost method is an application of ISTM D-5338.92, IS
Performed according to O CD 14855. That is, first, the amount of carbon contained in the test sample was measured by elemental analysis. Next, 15 parts of the test sample was added to 800 parts of the inocula, and the test was carried out at 58 ° C. for 40 days, the amount of carbon dioxide generated was measured, and the amount of carbon contained in the test sample was calculated based on the amount converted to carbon dioxide. The amount of generated carbon dioxide was expressed as a biodegradation rate (%). Here, some of the samples that are easily biodegradable promote the decomposition of even the carbon content in the inocula, and in this case, some of the samples have a value exceeding 100%.

Example 1 An aqueous solution of 3.00 parts of hexamethylenediamine dissolved in 10 parts of distilled water was added to a solution of 100 parts of polysuccinimide having a molecular weight of 96,000 dissolved in 400 parts of DMF under a nitrogen stream. After stirring at room temperature for 30 minutes, the stirring was stopped and the reaction was carried out for 20 hours. The reaction product was transferred to a mixer equipped with a bladed stirring blade, and 400 parts of distilled water and 400 parts of methanol were added.
The gel was chopped at 8000 rpm for 3 minutes, and 105.3 parts of N, N-dimethylaminopropylamine was added dropwise over 2 hours. After the addition, the mixture was further stirred for 24 hours. The product was discharged into 800 parts of methanol, and after stirring for 1 hour, the precipitate was collected by suction filtration, dried at 60 ° C, and dried at 60 ° C.
6 parts were obtained. The change in water absorption is as follows:
It was 0.457 and 0.397 in the aqueous pH solution, and the change in water absorption was small and good.

Example 2 The procedure of Example 1 was repeated, except that 79.5 parts of 2-mercaptoethylamine was used instead of N, N-dimethylaminopropylamine. After drying, 175 parts of a water-absorbing polymer were obtained. The change in water absorption is Na
0.378 for Cl aqueous solution, 0.278 for pH aqueous solution
The change in water absorption was small and good.

Example 3 In Example 1, Jeffamine M-600 (PE / EO = 9/1, molecular weight: 60) was used in place of N, N-dimethylaminopropylamine.
0) The same treatment as in Example 1 was carried out except that 154.5 parts were used and reacted for 100 hours. 25% in the resulting slurry
164.8 parts of an aqueous solution of caustic soda was added to adjust the pH to 12 or less, and the mixture was further stirred for 10 hours.
The resulting precipitate was filtered and dried to obtain 227 parts of a water-absorbing polymer. The change in water absorption is NaC
1 solution, 0.455, pH solution, 0.42
The change in water absorption was small and good.

Example 4 An aqueous solution in which 2.5 parts of hexamethylenediamine was dissolved in 10 parts of distilled water was added to a solution of 100 parts of polysuccinimide having a molecular weight of 113,000 dissolved in 400 parts of DMF under a nitrogen stream. After stirring at room temperature for 30 minutes, the stirring was stopped and the reaction was carried out for 20 hours. The reaction product was transferred to a mixer equipped with a blade with stirring blades, and a distilled water portion and a methanol portion were added.
The gel was minced at m for 5 minutes. The resulting gel is
It discharged little by little into 800 parts of 50% methanol water in which 7.7 parts of ethylenediamine were dissolved. After stirring for further 5 hours, the product was discharged into 800 parts of methanol, and after stirring for 1 hour, the precipitate was collected by suction filtration and dried at 60 ° C. to obtain 148 parts of a water-absorbing polymer. The change in water absorption is NaCl
The aqueous solution was 0.381, and the pH aqueous solution was as follows. The change in water absorption was small and 0.364 was good.

Comparative Example 1 The water absorption was measured in the same manner as in Example 1 using a cross-linked polyacrylic acid resin (Aqualic CAW, manufactured by Nippon Shokubai Co., Ltd.). It was 55 times with saline. On the other hand, when a biodegradability test was performed,
The biodegradation rate was 2.8%, showing little biodegradability. In addition, the change in water absorption is as follows:
0.159 and 0.082 in the pH aqueous solution, which was a large change in the amount of water absorption.

Comparative Example 2 Crosslinking agent lysine methyl ester dihydrochloride 6 under a stream of nitrogen
Parts were suspended in 200 parts of DMF and neutralized with 6 parts of triethylamine. A solution prepared by dissolving 50 parts of a polysuccinimide having a molecular weight of 130,000 in 250 parts of DMF was added to the solution, and the mixture was stirred at room temperature for 1 hour. The reaction solution was discharged into ethanol and dried to obtain 50 parts of a crosslinked polymer. The obtained polymer (26 parts) was suspended in 5000 parts of water, and a 2N aqueous NaOH solution was added dropwise to adjust the pH to 9 to 11, while hydrolyzing the remaining imide ring. The obtained reaction suspension was discharged into ethanol, filtered and dried to obtain 28 parts of a water-absorbing resin. A biodegradability test was performed using this water-absorbent resin in the same manner as in Example 1.
%, Indicating good biodegradability. However, the change in water absorption was 0.148 for the NaCl aqueous solution and 0.088 for the pH aqueous solution, which was a large change in the water absorption.

Comparative Example 3 100 parts of polysuccinimide were suspended in water having a pH of 10,
Heated at 60 ° C. for 1 hour, then neutralized with 10N HCl. 70 parts of L-aspartic acid and 50 parts of lysine hydrochloride were added to the obtained solution, and the mixture was reacted at 220 ° C. for 12 hours under a nitrogen stream. The obtained reaction product was suspended in distilled water and filtered and washed three times using distilled water. After freeze-drying, 225 parts of a water-absorbent resin were obtained. Example 1 using this water absorbent resin
When the biodegradability test was performed in the same manner as in
03%, indicating good biodegradability. However, the change in water absorption was 0.138 in the NaCl aqueous solution and 0.072 in the pH aqueous solution, which was a large change in the water absorption.

[0088]

As described above, a water-absorbing material which is biodegradable after use or disposal after being used for agriculture, horticulture, etc., has become possible to obtain a water-absorbent resin which is environmentally friendly and has excellent water absorbing ability. .

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

Claims (15)

[Claims] 1. A crosslinked polymer having a repeating unit represented by the formula (1) in a molecule. Embedded image (Where R, -X-, R 'and n are as follows: R is a pendant group having at least one nonionic polar group; -X- is -NH-, -NR '
—, —O—, or —S—. R ′ is an alkyl group, an aralkyl group, or an aryl group. n is 1 or 2
It is. ) 2. The nonionic polar group is represented by —NR ₁ ″ R ₂ ″,
-CONR ₁ "R _2", or "at least one selected from the group consisting of a polymer according to claim 1. (Wherein, R _1" -SR ₁ and R ₂ 'is hydrogen , An alkyl group, an aralkyl group, or an aryl group.) 3. The polymer according to claim 1, wherein the nonionic polar group is a polyether group. 4. The polymer according to claim 1, comprising 5 to 99.8% of the repeating unit represented by the formula (1) [formula 2]. Embedded image (Where R, -X-, R 'and n are as follows: R is a pendant group having at least one nonionic polar group; -X- is -NH-, -NR '
—, —O—, or —S—. R ′ is an alkyl group, an aralkyl group, or an aryl group. n is 1 or 2
It is. ) 5. The polymer according to claim 1, comprising 90 to 99.8% of a repeating unit represented by the formula (1) [formula 3]. Embedded image (Where R, -X-, R 'and n are as follows: R is a pendant group having at least one nonionic polar group; -X- is -NH-, -NR '
—, —O—, or —S—. R ′ is an alkyl group, an aralkyl group, or an aryl group. n is 1 or 2
It is. ) 6. The polymer according to claim 1, wherein n is 1. 7. The polymer according to claim 1, wherein -X- is -NH-. 8. A molecule characterized by reacting at least one compound selected from the group consisting of amines, alcohols and thiols having at least one nonionic polar group with a crosslinked polysuccinimide. A method for producing a crosslinked polymer having a repeating unit represented by the formula (1) in the formula (1). Embedded image (Where R, -X-, R 'and n are as follows: R is a pendant group having at least one nonionic polar group; -X- is -NH-, -NR '
—, —O—, or —S—. R ′ is an alkyl group, an aralkyl group, or an aryl group. n is 1 or 2
It is. ) 9. The method of claim 1, wherein the cross-linked acidic polyamino acid has at least one
Wherein at least one compound selected from the group consisting of amines, thiols, and alcohols having two nonionic polar groups is reacted by dehydration-condensation. ] The manufacturing method of the crosslinked polymer which has a repeating unit represented by these. Embedded image (Where R, -X-, R 'and n are as follows: R is a pendant group having at least one nonionic polar group; -X- is -NH-, -NR '
—, —O—, or —S—. R ′ is an alkyl group, an aralkyl group, or an aryl group. n is 1 or 2
It is. ) 10. The nonionic polar group is represented by —NR ₁ ″
_{R 2 ", -CONR 1" R} 2 ", or, -SR _1" is at least one selected from the group consisting of, claim 8 or 9
The method for producing a polymer described in the above. (Here, R ₁ ″ and R ₂ ″ are hydrogen, an alkyl group, an aralkyl group, or an aryl group.) 11. The method for producing a polymer according to claim 8, wherein the nonionic polar group is a polyether group. 12. The method for producing a polymer according to claim 8, comprising 5 to 99.8% of the repeating unit represented by the formula (1) [formula 6]. Embedded image (Where R, -X-, R 'and n are as follows: R is a pendant group having at least one nonionic polar group; -X- is -NH-, -NR '
—, —O—, or —S—. R ′ is an alkyl group, an aralkyl group, or an aryl group. n is 1 or 2
It is. ) 13. The polymer according to claim 8, comprising 90 to 99.8% of the repeating unit represented by the formula (1) [Formula 7]. Embedded image (Where R, -X-, R 'and n are as follows: R is a pendant group having at least one nonionic polar group; -X- is -NH-, -NR '
—, —O—, or —S—. R ′ is an alkyl group, an aralkyl group, or an aryl group. n is 1 or 2
It is. ) 14. The method for producing a polymer according to claim 8, wherein n is 1. 15. The method of claim 8, wherein -X- is -NH-.
15. The method for producing a polymer according to any one of items 14 to 14.