JPH026792B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to phosphorus-free sequestering agents. Various metal ion sequestering agents, such as condensed phosphorus, are used as a means of removing harmful heavy metals contained in industrial wastewater or soil discharged from various industries such as mines, smelting plants, metal processing plants, and textile factories. Acid salts, polyamine condensates of acrylic esters, etc. are known. However, these have drawbacks such as being expensive because they require a complicated process to manufacture, and the PH range is toward the high alkaline side, requiring a large amount of neutralizing agent, which limits the processing range. . Furthermore, when currently preparing detergents containing a surfactant as a main component, it is important to incorporate a builder composition as an auxiliary component to the main active agent component in order to improve the detergent performance. It is known that inorganic salts which exhibit alkalinity when dissolved in water can generally be used as detergent builders. Examples of these are carbonates, bicarbonates, phosphates, condensed phosphates, silicates, borates, etc. of alkali metals, especially sodium and potassium. Also, alkali metal salts, ammonium salts, mono-di-triethanolamine salts, etc. of organic carboxylic acids that form complex compounds or chelate compounds with polyvalent cations when made into an aqueous solution, such as nitrilotriacetate, ethylenediaminetetra Acetates, citrates, succinates, tartrates, fumarates, maleates, gluconates, etc. are also known as builders. Furthermore, polymerized aliphatic polycarboxylic acid salts are known to be effective as builders. Known examples belonging to these include polymaleic acid, polyitaconic acid, salts of olefin-maleic acid copolymers, and salts of alkyl vinyl ether-maleic acid copolymers. Among these many builder compositions, phosphates and condensed phosphates are the most effective and are used in large amounts. The amount of other compounds used is limited due to economic efficiency, workability, safety, etc., and currently they are not used except in specific cases. However, when phosphates and condensed phosphate builders are flushed away as wastewater after washing, they flow into lakes and rivers, promoting the growth of algae and causing eutrophication. For this reason, builders that do not contain phosphorus are being developed, and many builders have been proposed. For example, polymer electrolytes have poor biodegradability and have not yet achieved the same level of effectiveness as sodium tripolyphosphate. In addition, compounds containing nitrogen have recently been reported, but nitrogen, like phosphorus, is a source of eutrophication and is therefore undesirable. The present inventors have conducted intensive studies to find a metal ion sequestering agent with excellent biodegradability that can replace phosphates and condensed phosphates. ) or isotactic poly(acrylic acid) having an average molecular weight of 500 to 50,000, or their alkali metal or amine salts have excellent biodegradability and excellent performance as a metal ion sequestering agent, and the present invention has been achieved. . The metal ion sequestering agent used in the present invention has an effect as a detergent builder equal to or greater than that of phosphorus builders such as sodium tripolyphosphate, and can be used not only alone but also in combination with phosphorus builders. It is also possible to reduce the amount used, and it is also possible to further reduce the amount of active agent blended. Furthermore, the metal ion sequestering agent of the present invention is extremely effective in preventing the formation of scale in boilers and the like and in removing the formed scale. Furthermore, the sequestering agent of the present invention is extremely useful for detoxifying soil contaminated with harmful metals. Furthermore, the sequestering agent of the present invention can be used in various products whose decomposition and deterioration are accelerated by the presence of trace amounts of metal ions; hydrazine, hydrogen peroxide, soda percarbonate, bleaching powder, formalin, lanolin products, plastics, etc. It is effective for stabilization and can also be used as an electrolyte for electroplating. Moreover, since the sequestering agent of the present invention has good biodegradability, it does not pollute the environment with waste water after being used for the above purpose. In the present invention, the alkali metals constituting the isotactic poly(methacrylic acid) or the isotactic poly(acrylic acid) salt include sodium,
Potassium and lithium are mentioned, and examples of the amine include ammonia, mono-, di- or tri-ethanolamine, morpholine and the like, and these salts may naturally be partial salts. The molecular weight range of isotactic poly(methacrylic acid) or its salt is about 500 to 10,000, preferably 800 to 7,000, and most preferably 1,000 to 5,000. The molecular weight range of the salt is about 500-50000,
The range is preferably 800 to 30,000, and most preferably 1,000 to 20,000. Further, the poly(methacrylic acid) (salt) and poly(acrylic acid) (salt) of the present invention may be a copolymer of both. The isotactic poly(methacrylic acid) (salt) or isotactic poly(acrylic acid) (salt) used in the present invention is preferably a homopolymer, but a small proportion of other copolymerizable It may also be a copolymer with a comonomer. Examples of the monomer include maleic anhydride, methyl vinyl ether, vinyl acetate, vinylpyrrolidone, itaconic acid, aconitic acid, citraconic acid, fumaric acid, styrene, butadiene, isoprene, and the like. The compound of the present invention can be blended with either an anionic activator or a nonionic activator, and can be arbitrarily blended with various known activators regardless of their type. The compound can be used alone as a detergent builder, or can be used in combination with other inorganic or organic builders. For example, it can completely or partially replace a phosphorus-based builder such as sodium tripolyphosphate. Moreover, even if it coexists with various compounds commonly added to cleaning compositions, its effectiveness will not be impaired in any way. The amount of the compound of the present invention added to the detergent composition is not particularly limited, and sufficient effects can generally be obtained with the amount of the compound added to the builder. The present invention will be explained below with reference to synthesis examples and examples of compounds according to the present invention. Note that the term "%" simply means "% by weight" unless otherwise specified. Synthesis Example 1 Synthesis of isotactic poly(sodium methacrylate) (hereinafter abbreviated as It-PMA) Inject dry nitrogen into a flask equipped with a stirrer, a thermometer, a nitrogen inlet and exhaust pipe, and a sample injection port with a syringe cap. Weigh out dry toluene and 3.2M phenylmagnesium bromide/ether solution under the conditions shown in Table 1 while flowing
Inject methyl methacrylate (MMA) using a syringe while stirring at 2°C.
The reaction was carried out for 24 hours. Then, methanol was gradually added to stop the polymerization, and the reaction mixture was diluted with 8% hydrochloric acid 1
The precipitated white oligomer was added to the solution while stirring and was vacuumed and dried. Then 150ml of acetone
Dissolve the insoluble matter, separate the insoluble matter, and add 8% hydrochloric acid 1 part to the solution.
The catalyst component in the oligomer was removed. Next, the precipitated oligomer was washed with water, and further purified by repeating the steps of dissolving the oligomer in a small amount of acetone, pouring it into a large amount of water, and re-precipitating it. Poly(methyl methacrylate)
(PMMA) was obtained. About methyl ester
Determined by VPO method, further IR and elemental analysis,
The molecular structure was confirmed by NMR. then 1.5
130 with double equivalent of 20% sodium hydroxide for about 3 days.
Heat saponification was performed at ℃ to obtain It-PMA. The molecular weight of It-PMA was calculated from the molecular weight of the corresponding methyl ester. synthesis conditions,
The conversion rate and analysis results are shown in Table 1.

[Table] Synthesis example 2 Isotactic poly(sodium acrylate)
Synthesis of (hereinafter abbreviated as It-PA) In the same manner as in Synthesis Example 1, methyl acrylate (MA) was used as an anionic catalyst, phenylmagnesium bromide (PhMgBr) or lithium tetrahydridoaluminate [LiAlH ₄ ] was used as a solvent. Solution polymerization was carried out at low temperature using dry toluene and the reaction was stopped by adding methanol. The reaction mixture was poured into methanol acidified with hydrochloric acid, and the catalyst components were decomposed by stirring. Thereafter, fractional precipitation was performed to separate oligomers with the desired molecular weight. Furthermore, in order to remove the catalyst component in the oligomer, the operations of dissolving it in acetone, filtering it, concentrating the solution, and pouring it into a large amount of water to reprecipitate it were repeated. The purified oligomer was dried under reduced pressure at 60°C to obtain isotactic poly(methyl acrylate) (PMA). The structures of these methyl esters were confirmed by IR, elemental analysis, and NMR. Next, the methyl ester was purified by heating and saponifying it with 1.2 equivalents of a 20% aqueous sodium hydroxide solution for over 24 hours, dissolving it in a small amount of water, and repeating reprecipitation by pouring it into a large amount of ethanol. Drying was carried out under reduced pressure at 100°C to obtain almost the theoretical amount of It-PA. The molecular weight of It-PA was calculated from the molecular weight of the corresponding methyl ester. Synthesis conditions and analysis results are shown in Table 2.

[Table] Example 1 The cleaning power test was carried out using a cotton face stain stain cloth as the naturally contaminated cloth, and the judgment was made using Scheffe's paired comparison method, repeated on 4 sheets (left and right), and visually judged.
For comparison, commercially available sodium tripolyphosphate and sodium oxadiacetate were also tested each time. The washing conditions and detergent composition are as follows. (i) Washing detergent concentration 0.12% Washing temperature 25℃ Washing time 8 minutes Washing machine used Household whirlpool electric washing machine bath Ratio 1:30 Water used 3゜DH tap water (ii) Rinse water Temperature 25℃ Washing machine used Rinse time 3 minutes (iii) Detergent composition Sodium alkylbenzenesulfonate (LAS MW346) 20% Sample builder 25% Sodium silicate No. 2 5% Anhydrous sodium carbonate 3% Carboxymethyl cellulose (CMC) 0.5% Anhydrous sodium sulfate 46.5% Cleaning power The results of the test are shown in Table 3. The evaluation was made with the effect of sodium oxadiacetate as 0 and the effect of sodium tripolyphosphate as 10.

【table】

[Table] Example 2 Sample builder in a 50ml beaker equipped with a rotor.
Weigh out 10 mg, dissolve it in 50 ml of 1.0 x 10 ^-3 M calcium chloride aqueous solution, add 1 ml of 4.0 M potassium chloride aqueous solution as an ionic strength adjusting agent to adjust the ionic strength μ = 0.08, and store in a constant temperature bath at 30°C. Stir and measure the calcium ion strength after 10 minutes using a calcium ion electrode (Orion Model 93-20)
Using an ion meter (Toa Denpa Kogyo KKIM)
-20E), and the calcium ions sequestered by 1 g of sample builder are shown as calcium carbonate equivalent values. The results are shown in Table 4.

[Table] Example 3 Using 0.1g/aqueous solution of each sample, JIS K0102
A biodegradability test was conducted according to the following. The results are shown in Table-5.

[Table] Example 4 A detergency test was conducted in the same manner as in Example 1 using the samples shown in Table 6. Further, the dispersion power of manganese dioxide was evaluated by the method shown below. The results are shown in Table-6. <Manganese dioxide dispersion power evaluation method> Manganese dioxide was added to a 50ml graduated test tube.
Take 1.0g and 50ml of 0.05% sample builder aqueous solution,
After shaking up and down 100 times, leave it in a constant temperature bath at 25°C for 4 hours. Then, 15 ml of the suspension was collected without disturbing the contents as much as possible. The amount of manganese dioxide in the collected suspension was measured by the potassium permanganate method. Dispersion power was expressed by the number of mg of manganese dioxide suspended in 100 ml of suspension. The results are shown in Table-6.

【table】

[Table] Same.
Example 5 Using 0.1g/aqueous solution of each sample, JIS K0102
A biodegradability test was conducted according to the following. The results are shown in Table-7.

[Table] Example 6 In order to examine the effectiveness of the sequestering agent of the present invention as a soil treatment agent, the following test was conducted using cadmium-contaminated soil. A cylinder with a diameter of 10 cm was filled with 1 m of soil contaminated with 20 ppm of cadmium.
1000 ml of 0.05% sequestering agent aqueous solution was flowed.
The amount of cadmium in the contaminated soil was then measured. The results are shown in Table-8.

[Table] Example 7 In order to examine the scale generation prevention effect of the metal ion sequestering agent of the present invention, a concentration of 10 ppm was added to boiler water.
Sequestering agent (It-PMA-
2120) was dissolved and operated for one year. As a result, no scale was observed.

Claims (1)

[Claims] 1 Isotactic poly(methacrylic acid) having an average molecular weight of 500 to 10,000 or an average molecular weight of 500 to 10,000
Isotactic poly(acrylic acid) with 50000
Or a metal ion sequestering agent containing these alkali metal salts or amine salts as active ingredients.