JPH11221596A - Water treating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain equal or higher blodegradability than that of a conventional polyaspartic acid polymer and to improve scale preventing performance by incorporating an aspartic acid polymer having repeating units expressed by formula I and/or formula II and repeating units expressed by formula III and/or formula IV. SOLUTION: This water treating agent contains an aspartic acid polymer having repeating units expressed by formula I and/or formula II and repeating units expressed by formula III and/or formula IV. In formulae I and II, M represents hydrogen, alkali metals, alkaline earth metals. ammonium group or org. amine groups and may be same or different for each repeating unit. In formulae III and IV, R is a phenyl group in which at least one sulfonic acid groups is substituted. The mol.wt. of the aspartic acid polymer of the water treating agent is preferably between >=300 and <=500000. The mol.wt. can be controlled by controlling the reaction conditions such as reaction temp., reaction time, presence or absence of an acid catalyst or its amt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a water treatment agent. More specifically, the present invention relates to a water treatment agent containing an aspartic acid-based polymer having a phenyl group containing at least one sulfonic acid in a side chain.

[0002]

2. Description of the Related Art Since polyaspartic acid has excellent biodegradability, its use as a water treatment agent such as a detergent builder or a scale inhibitor has been studied. However, although it is superior in biodegradability to various polymers conventionally used in each application, it has not been put to practical use yet because it is inferior in various properties such as dispersing ability and metal ion chelating ability.

[0003] As an attempt to improve the water treatment agent of polyaspartic acid, particularly the scale-preventing performance, Japanese Patent Application Laid-Open No. 8-502 is disclosed.
No. 690 discloses polyaspartic acid having a hydrophobic group such as an alkyl group or an alkenyl group having 8 to 20 carbon atoms in a side chain. However, although biodegradability can be expected as compared with conventional acrylic acid-based polymers, there is a problem that sufficient anti-scale performance is not obtained.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an aspartic acid-based polymer having a biodegradability equal to or higher than that of a conventional polyaspartic acid-based polymer and having a high scale-inhibiting performance. It is an object of the present invention to provide a water treatment agent comprising:

[0005]

Means for Solving the Problems In order to solve the above problems, the present invention provides the following general formulas (1) and / or (2)
And a repeating unit represented by the following general formula (3) and / or
Or a water treatment agent comprising an aspartic acid-based polymer having a repeating unit represented by (4).

[0006]

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(However, in the general formulas (1) and (2), M
Represents hydrogen, an alkali metal, an alkaline earth metal, an ammonium group or an organic amine group, and may be the same or different for each repeating unit. )

[0008]

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(However, in the general formulas (3) and (4), R
Represents a phenyl group substituted with at least one sulfonic acid group. The present invention also provides a modified polysuccinimide obtained by subjecting a monomer capable of being converted into a polysuccinimide by thermal condensation polymerization to a compound represented by the following general formula (5) to obtain a modified polysuccinimide. Provided is a water treatment agent containing an aspartic acid-based polymer obtained by hydrolysis.

[0010]

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(However, in the general formula (5), R1 and R2 each represent a sulfonic acid group or hydrogen, and at least one is a sulfonic acid group.) In the above, a monomer which can be converted into a polysuccinimide by thermal condensation polymerization An acid is added to an aqueous solution containing a salt of the compound of formula (5) and a salt of a compound represented by the following general formula (5) to precipitate crystals, followed by thermal condensation polymerization to obtain a modified polysuccinimide. Provided is a water treatment agent containing an aspartic acid-based polymer obtained by hydrolyzing an acid imide.

[0012]

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(However, in the general formula (5), R1 and R2 each represent a sulfonic acid group or hydrogen, and at least one is a sulfonic acid group.)

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An aspartic acid polymer according to the water treatment agent of the present invention will be described together with a production method.

Usually, polyaspartic acid includes aspartic acid, ammonium maleate, ammonium fumarate,
The polysuccinimide can be obtained by subjecting a monomer capable of becoming a polysuccinimide by thermal polycondensation such as maleamic acid or maleimide to thermal polycondensation to obtain a polysuccinimide and then hydrolyzing it. Here, as the aspartic acid, any of DL-aspartic acid, L-aspartic acid, and D-aspartic acid can be used.

The aspartic acid-based polymer according to the water treatment agent of the present invention is prepared by, for example, (method 1) thermal condensation polymerization of a monomer capable of forming polysuccinimide by thermal condensation polymerization and a compound represented by the general formula (5). After obtaining the modified polysuccinimide, the modified polysuccinimide is hydrolyzed.

(Method 2) A compound represented by the general formula (5) is reacted with a polysuccinimide-based polymer obtained by subjecting a monomer capable of becoming a polysuccinimide by thermal condensation polymerization to thermal condensation and then hydrolyzed. .

Is obtained.

Polysuccinimide repeating unit:

[0020]

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By hydrolysis of the compound represented by the general formula (1)
And / or a repeating unit of polyaspartic acid represented by (2) is obtained. The aspartic acid polymer according to the present invention contains a repeating unit represented by the general formula (1) and / or (2), and may be a main component. “Main component” means that the total amount of the repeating units represented by the general formulas (1) and (2) is 50 m
ol% or more. In order to increase the water solubility, it is preferably at least 60 mol% of the whole,
More preferably, it is 0 mol% or more. The ratio of the general formulas (1) and (2) is not particularly limited, and varies depending on hydrolysis conditions and the like.
It can be used in a range of about 9 to 99: 1. M in the general formulas (1) and (2) is hydrogen, an alkali metal, an alkaline earth metal, an ammonium group or an organic amine group, and may be the same or different for each repeating unit. Of these, alkali metals are preferred from the viewpoint that the hydrolysis rate is high. By selecting the type of the hydrolyzing agent used in the hydrolysis, it is possible to adjust which group M is.

The aspartic acid polymer according to the water treatment agent of the present invention is characterized by containing a repeating unit represented by the general formula (3) and / or (4).
In the above (Method 1) and (Method 2), by using the compound represented by the general formula (5), a repeating unit represented by the general formula (3) and / or the general formula (4) is formed in the polymer. However, it is needless to say that the present invention is not limited to these manufacturing methods. The relationship between the general formulas (3) and (4) is the same as the relationship between the general formulas (1) and (2), and the ratio of the general formulas (3) and (4) is not particularly limited, and the molar ratio is usually Can be used in the range of about 1:99 to 99: 1.

In the general formulas (3) and (4), it is important that R is a phenyl group substituted with at least one sulfonic acid group, thereby providing both a hydrophilic group and a hydrophobic group, and This has the effect of improving performance. Examples of the phenyl group substituted with at least one sulfonic acid group include a phenyl group substituted with one sulfonic acid group, a phenyl group substituted with two sulfonic acid groups, and a combination thereof. In particular,
The residue (R) of the compound exemplified later as the compound represented by the general formula (5) may be mentioned.

The above effect can be obtained if at least one repeating unit represented by the general formulas (3) and / or (4) is present in the polymer, but is represented by the general formulas (3) and (4). The total amount of repeating units is 0.01
mol% or more, more preferably 0.1 mol% or more. In addition, the upper limit is set to 40 mol% from the viewpoint of preventing a decrease in the amount of carboxylic acid.
Or less, more preferably 30 mol% or less.

The molecular weight of the aspartic acid polymer according to the water treatment agent of the present invention is preferably from 300 to 500,000, more preferably from 500 to 200,000. It can be controlled by adjusting reaction conditions such as reaction temperature, reaction time, presence or absence and amount of an acid catalyst.

The method for producing an aspartic acid polymer according to the water treatment agent of the present invention will be described in more detail. In the following description, these items are common to the method 1 and the method 2 unless otherwise specified.

At the time of the thermal polycondensation, an amino acid or a polyfunctional monomer having two or more functional groups may be copolymerized. Examples of such amino acids include glycine, alanine, phenylalanine, leucine, isoleucine, valine, methionine, cysten, cysteine, serine, threonine, glutamic acid, α-amino-adipic acid, aminomalonic acid, α-amino-sebacic acid , Α-methylglutamic acid, β, β-dimethylaspartic acid, ornithine,
Lysine, arginine, histidine, β-alanine, β-
Phenylalanine, β-aminobutyric acid, α-methyl-β-
Aminopropionic acid, isoserine, β-tyrosine, taurine and the like.Examples of polyfunctional monomers include diamines such as ethylenediamine and hexamethylenediamine, polyamines such as diethylenetriamine, dicarboxylic acids such as succinic acid, and polycarboxylic acids. Is mentioned. These may be used alone or in combination of two or more. In this case, the amount of the amino acid or the polyfunctional monomer having two or more functional groups is preferably less than 50% by weight of the whole. If it is more than this, the water solubility will decrease,
It may not be dissolved in water.

In the thermal polycondensation reaction, the mixture of the raw materials is preferably heated to 110 to 300 ° C, more preferably 150 to 270 ° C.
By heating to a temperature of The time of the thermal polycondensation reaction varies depending on conditions such as the reaction temperature, the reaction pressure, and the type of the apparatus, but usually requires 1 minute to 12 hours. The apparatus for heating is not particularly limited, and examples thereof include a batch mixer and a continuous mixer capable of uniformly heating a mixture of raw materials.

The thermal polycondensation reaction can be carried out at normal pressure without any problem as long as the generated water can be removed from the reaction system. However, in order to remove the generated water more efficiently, the reaction must be carried out under reduced pressure. Is also good.

In the heat condensation polymerization reaction, a heat condensation polymerization catalyst may be used, if necessary. Examples of the thermal condensation polymerization catalyst include phosphoric acid, phosphorus pentoxide, polyphosphoric acid, alkylphosphonic acid, arylphosphonic acid, phosphorous acid, hypophosphorous acid / nitric acid, nitrous acid / sulfuric acid, sulfurous acid, alkylsulfonic acid, arylsulfonic acid / hydrochloric acid, Chloric acid, chlorous acid, hypochlorous acid / bromic acid, bromic acid, hypobromite / iodic acid / molybdic acid, tungstic acid, hydrogen sulfide, hydrogen bromide, sodium bisulfate, potassium bisulfate, ammonium bisulfate And the like.

The heat condensation polymerization may be carried out without a solvent.
It may be performed in a solvent. Examples of the solvent include solvents such as ethylene glycol, glycerin, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, tetralin, dodecyl alcohol, dimethylformamide, and dimethyl sulfoxide.

As the compound represented by the general formula (5),
For example, aminobenzenesulfonic acids such as 2-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid sulfonic acid, and 4-aminobenzenesulfonic acid;
Aminobenzene disulfonic acids such as 1,4-benzenedisulfonic acid.

The amount of the compound represented by the general formula (5) is designed so that one or more repeating units represented by the general formulas (3) and / or (4) are present in one molecule of the polymer. The amount is preferably 0.1% by weight or more based on a monomer which can be converted into polysuccinimide by thermal condensation polymerization.

In the method 1, a monomer capable of forming a polysuccinimide by thermal condensation polymerization, a compound represented by the general formula (5), and if necessary, other raw materials are mixed and then subjected to thermal condensation polymerization. In particular, when aspartic acid is used as a monomer and no solvent is used, a pretreatment step of adding an acid to an aqueous solution containing a salt of aspartic acid and a salt of the compound represented by the general formula (5) to precipitate crystals. , It is preferable to carry out thermal polycondensation. By performing such a pretreatment step, aspartic acid and the compound represented by the general formula (5) are uniformly mixed in the crystal.
Salt bases in this case include sodium, potassium,
Examples of the acid include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, maleic acid, fumaric acid, and aspartic acid.

In the method 2, a polysuccinimide is obtained by subjecting a monomer capable of being converted to a polysuccinimide by thermal condensation polymerization and, if necessary, a raw material to other monomers to obtain a polysuccinimide. Reaction with the compound represented by (5). The reaction between the polysuccinimide and the compound represented by the general formula (5) is preferably performed in a solvent. As the solvent, the same solvent as the solvent used in the above-mentioned thermal condensation polymerization, such as water or ethylene glycol, is used. The reaction is preferably carried out by heating to a temperature of 20 to 300C, more preferably 40 to 270C.

The hydrolysis of the modified polysuccinimide can be carried out in the same manner as in the known hydrolysis of polysuccinimide. As a hydrolyzing agent used for hydrolysis,
Acid compounds and alkali compounds can be mentioned. As the acid compound, inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid are preferable, and as the alkali compound, hydroxides of alkali metals and alkaline earth metals such as sodium hydroxide, potassium hydroxide, calcium hydroxide and lithium hydroxide are preferable. Or alkali metal or alkaline earth metal carbonates such as sodium carbonate, calcium carbonate and lithium carbonate; and organic amines such as ammonia, monoethanolamine, diethanolamine and triethanolamine.

As the water treatment agent of the present invention, the aforementioned aspartic acid-based polymer may be used alone, or a phosphorus-based agent such as a polymerized phosphate or a phosphonate, or a metal salt such as zinc, chromium, or manganese. And a composition containing other anticorrosive agents, slime control agents, chelating agents and the like. The water treatment agent of the present invention is effectively used to prevent metal corrosion and scale in water systems such as boiler water, cooling water, seawater desalination equipment, oil fields, pulp digesters, and black liquor concentrators. is there. These water systems can be used in the same manner as conventionally known water treatment agents, for example, by injecting quantitatively or intermittently so that the concentration in circulating water becomes constant.

[0038]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

<Example 1> Ammonium maleate 3
9.9 g and 5.2 g of sulfanilic acid (4-aminobenzenesulfonic acid) were mixed in a mortar and heated at 200 ° C. for 2 hours. The obtained powder was dispersed in water and hydrolyzed with a 48% aqueous sodium hydroxide solution to obtain polymer A. The weight average molecular weight of polymer A was determined by GPC (gel permeation chromatography). Next, the performance as a water treatment agent was evaluated. 2 pp of polymer A in water
m, 5 mmol / l of calcium chloride, 5 mmol / l of sodium hydrogen carbonate, and 100 ml of a test solution prepared with a 1% aqueous solution of NaOH so as to have a pH of 8.5 were prepared. After sealing the test solution, it was allowed to stand at 60 ° C. for 20 hours. After cooling, the solution was filtered through a 0.1 μm membrane filter, and the calcium concentration in the filtrate was measured. The calcium carbonate scale inhibition rate was determined by the following equation.

Scale inhibition rate (%) = (γ−β) / (α)
-Β) × 100 In the formula, α: Calcium concentration in the liquid before the test (ppm) β: Calcium concentration in the filtrate when no polymer is added (ppm) γ: Calcium concentration in the filtrate for each polymer (ppm) Example 2 39.9 g of ammonium maleate and 5.2 g of metanilic acid (3-aminobenzenesulfonic acid) were mixed in a mortar and heated at 200 ° C. for 2 hours. The obtained powder was dispersed in water and hydrolyzed with a 48% aqueous sodium hydroxide solution to obtain polymer B. In the same manner as in Example 1, the weight average molecular weight was determined, and the ability to inhibit calcium carbonate scale was evaluated.

Example 3 L-aspartic acid 13.3
1 g, metanilic acid (3-aminobenzenesulfonic acid)
About 50 g of water and 9.18 g of a 48% aqueous sodium hydroxide solution were added to 1.73 g, and dissolved. 5.4 g of 96% sulfuric acid was added thereto to precipitate crystals. The crystals were separated by filtration, washed with water, dried at 115 ° C., and pulverized in a mortar. Next, 200
Heated at ° C for 2 hours. The obtained powder is dispersed in water and 4
Hydrolysis was performed with an 8% aqueous sodium hydroxide solution to obtain polymer C. In the same manner as in Example 1, the weight average molecular weight was determined, and the ability to inhibit calcium carbonate scale was evaluated.

<Comparative Example 1> (Polyaspartic acid as raw material of ammonium maleate) 10.97 g of ammonium maleate was added at 250 ° C for 3 hours.
Heated for 0 minutes. Disperse the obtained powder in water and add 48%
Hydrolysis with an aqueous solution of sodium hydroxide gives polymer D
I got In the same manner as in Example 1, the weight average molecular weight was determined, and the ability to inhibit calcium carbonate scale was evaluated.

<Comparative Example 2> (Aspartic acid raw material polyaspartic acid) 13.31 g of DL-aspartic acid was heated at 250 ° C for 1 hour. The obtained powder was dispersed in water and hydrolyzed with a 48% aqueous sodium hydroxide solution to obtain Polymer E. In the same manner as in Example 1, the weight average molecular weight was determined, and the ability to inhibit calcium carbonate scale was evaluated.

Comparative Example 3 (Aspartic acid raw material laurylamine-modified polyaspartic acid) 80 g of dimethylformamide was added and dissolved in 20 g of polysuccinimide obtained by heating DL-aspartic acid at 250 ° C. for 1 hour. . Thereto, 3.8 g of laurylamine was added, and the mixture was heated and stirred at 80 ° C. for 3 hours. Next, it was poured into a large amount of methanol. The precipitate formed was separated by filtration and dried in a vacuum drier at 50 ° C.
The resultant was dispersed in water and hydrolyzed with a 48% aqueous sodium hydroxide solution to obtain a polymer F. In the same manner as in Example 1, the weight average molecular weight was determined, and the ability to inhibit calcium carbonate scale was evaluated.

[0045]

[Table 1]

[0046]

According to the present invention, the modified aspartic acid-based polymer, which is an essential component, exhibits biodegradability equal to or higher than that of conventional polyaspartic acid, and has a scale-inhibiting performance.
It has high gelation resistance and dispersion performance, and has excellent performance as a water treatment agent.

Claims (3)

[Claims] 1. The following general formula (1) and / or (2)
And a repeating unit represented by the following general formula (3) and / or
Or a water treatment agent comprising an aspartic acid-based polymer having a repeating unit represented by (4). Embedded image (However, in the general formulas (1) and (2), M represents hydrogen, an alkali metal, an alkaline earth metal, an ammonium group or an organic amine group, and may be the same or different for each repeating unit. ) (However, in the general formulas (3) and (4), R represents a phenyl group substituted with at least one sulfonic acid group.) 2. A modified polysuccinimide is obtained by polycondensation of a monomer capable of forming a polysuccinimide by thermal polycondensation and a compound represented by the following general formula (5), followed by hydrolysis of the modified polysuccinimide. Water treatment agent containing aspartic acid-based polymer. Embedded image (In the general formula (5), R1 and R2 each represent a sulfonic acid group or hydrogen, and at least one is a sulfonic acid group.) 3. A salt of aspartic acid and a compound represented by the following general formula (5):
An acid is added to an aqueous solution containing a salt of a compound represented by the formula (1) to precipitate crystals, and then subjected to thermal polycondensation to obtain a modified polysuccinimide, followed by hydrolysis of the modified polysuccinimide. A water treatment agent comprising the aspartic acid-based polymer described in the above. Embedded image (In the general formula (5), R1 and R2 each represent a sulfonic acid group or hydrogen, and at least one is a sulfonic acid group.)