JPS60195176A - Metal sequestering agent - Google Patents

Abstract

PURPOSE:To provide a metal sequestering agent having excellent biodegradability, containing a copolymer having a specific molecular weight and composed of a monomer unit such as alkyl vinyl ether and a monomer unit such as acrylic acid, etc., or its alkali metal salt, etc. as an active component. CONSTITUTION:The objective metal sequestering agent contains, as an active component, a copolymer having an average molecular weight of 500-100,000 and containing (A) one or more monomer units selected from alkyl vinyl ether, alkyl vinylsulfide (alkyl or both components is <=3C) and vinyl alcohol and (B) one or more monomer units selected from acrylic acid and methacrylic acid, or alkali metal salt or amine salt of the copolymer. USE:Removal of harmful heavy metals from industrial waste water or soil. A detergent builder having similar effect to a phosphorus-based builder, and the prevention or removal of scale of boiler, etc.

Description

[Detailed description of the invention] The present invention relates to phosphorus-free sequestering agents.

Glaze is used as a means to remove harmful heavy metals contained in industrial wastewater or soil discarded from mines, smelting plants, gold processing plants, spinning factories, etc. Various metal ion pricking agents are known, such as condensed phosphates and polyamine condensates of acrylic esters. However, these methods have drawbacks such as being expensive due to complicated manufacturing processes, and limiting the processing range because the pH range is toward the high alkaline side and a large amount of neutralizing agent is required. there were.

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 enhance 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, when made into an aqueous solution, complex compounds with respect to polyvalent cations,
All alkali groups of organic carboxylic acids, such as forming chelate compounds, ammonium salts.

Mono-di-triethanolamine salts such as nitrilotriacetate, ethylenediaminetetraacetate, citrate, succinate, tartrate, fumarate, maleic salt, gluconate, etc. are also known as builders.

Furthermore, it is known that polymerized aliphatic polycarboxylic acid groups are immobile as builders. Known examples of these include polymaleic acid, polyitaconic acid, and olefin-maleic acid copolymer Hayabusa.

Among these many builder compositions, phosphate and condensed phosphorus IWi ammonium salt 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, phosphates and condensed phosphate builders are
If it is flushed away as post-effluent, it will flow into lakes and rivers, encouraging algae growth and causing field nutrient enrichment. Builders that do not contain this waste phosphorus are being developed, and many builders have been proposed.

For example, polymer frost and solute have poor biodegradability, and they 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 search for metal ion sequestering agents with excellent biodegradability that can replace phosphates and condensed phosphates. containing at least one monomer unit selected from the group consisting of (the number of atoms is 3 or less) and vinyl alcohol, and at least one monomer unit selected from acrylic acid and methacrylic acid, and having an average molecular weight of 500 to 100,000. The inventors have discovered that a copolymer or its alkali metal salt or amine salt has excellent performance as a gold ion sequestering agent, and has arrived at the present invention.

The metal ion sequestering agent used in the present invention has an effect as a detergent builder equal to or greater than the phosphorus-based bilgu of sodium tripolyphosphate group 4, and can be used not only alone but also in combination with the phosphorus-based bilgu. It is also possible to reduce the amount used, and it is also possible to further reduce the amount of the active agent blended.

Furthermore, the sequestering agent of the present invention is extremely effective in preventing scale formation in boilers and the like and in removing scale formed therein.

Furthermore, the total ion sequestering agent of the present invention is extremely unnecessary for the detoxification of soil piles contaminated with harmful substances.

Historically, the metal ion press agent of the present invention is one of the few products whose decomposition and deterioration are promoted by the presence of trace amounts of metal ions;
It is also used for the stabilization of hydrazine, hydrogen peroxide, supercarbohydrated soda, bleaching powder, formalin, lanolin products, plastics, etc., and is also used for 'il+ for 'ii and i plating.
, It can also be used as a pre-liquid.

Moreover, since the sequestering agent according to the present invention has good biochemical properties, it will not contaminate JA, M1- with waste water after being used for the above purpose.

In the present invention, the alkali metals constituting the base of the copolymer include sodium, potassium, and lithium.
As amines, mention may be made of ammonia, mo/-, triethanolamine, morpholine, etc., and these salts may of course be partially substituted.

The alkyl vinyl ether unit used in the present invention is preferably methyl vinyl ether, but ethyl vinyl ether or propyl vinyl ether can also be used.

In the case of a copolymer of alkyl vinyl ether and (meth)acrylic acid, it is preferable to contain 2 to 40 mol%, particularly preferably 5 to 35 mol%, of alkyl vinyl ether units, and the average molecular weight is about 1,000 to 50,000. good.

As the alkyl vinyl sulfite used in the present invention, methyl vinyl sulfide is preferred, but ethyl vinyl sulfite and yafrobil vinyl sulfide can also be used.

In the case of a copolymer of alkyl vinyl sulfide and (meth)acrylic acid, the number of alkyl vinyl sulfide units is 2 to 4.
It is preferably contained in an amount of 0 mol %, particularly 5 to 30 mol %, and preferably has an average molecular weight of about 2,000 to 90,000.

The copolymer containing vinyl alcohol units used in the present invention can be obtained by copolymerizing a vinyl ester such as r-vinyl ester and (meth)acrylic acid, and then hydrolyzing the copolymer.
The content of vinyl alcohol units is preferably 6 to 40 mol %, particularly preferably 5 to 30 mol %, and the average molecular weight is 1000 to 20,000, with a particularly good bite. O
It is preferably DD~15,000.

In either case, the polymerization method itself may be a known method.

The compound of the present invention can be blended with anionic activators and nonionic oil-based agents, and can be blended with various known activators regardless of their type. It can be used alone as a detergent builder, and can also be used in combination with other inorganic or organic builders.For example, it can completely replace glues such as sodium tripolyphosphate and R-based builders. The compound of the present invention can be used as a substitute for or partially substituted for it.Also, even if it coexists with various formulations that are usually added to cleaning compositions, its effectiveness will not be impaired. There is no particular limit to the amount of bilgoo added to the product, and sufficient effects can be obtained with the usual amount of bilgoo added and four ounces of bilgoo.

The present invention will be explained below with reference to synthesis examples and practical examples of compounds according to the present invention. However, unless otherwise specified, the term ``%'' shall mean ``% by weight.''

Synthesis Example 1 Synthetic glass material of melal vinyl ether-sodium acrylate copolymer (hereinafter abbreviated as P (MVE-A)) - Methyl vinyl ether (hereinafter abbreviated as MVE) and methyl acrylate (hereinafter abbreviated as MθA) in tocrepe 30% toluene solution of each of the following is added in the molar ratio of methyl vinyl ether/methyl acrylate shown in Table 1, and benzoyl peroxide (hereinafter abbreviated as BPO) is added to the total amount of both monomers by 7 to 10 mol in Table 1. In an argon atmosphere, 1-butanethiol (hereinafter abbreviated as Bu, SH) was used in a molar ratio of 'i'y-1 with respect to the total of both monomers as a continuous cutting. Polymerization was carried out at 80°C for 5 hours while stirring for 1υ9 hours. After cooling, the reactants were added to the grooves to form a copolymer, and the copolymer was purified by reprecipitation with chloroform and hexane to give an average molecular weight of 1 by the VPO method.
After determining the presence of functional groups by fla and measuring the polymerization ratio by element weight, it was reacted with 20% sodium hydroxide water bath solution of 1.5 times the amount in an autoclave at 130'C for 3 days to form sodium salt. .

Synthesis Example 2 Synthesis of Methyl Vinyl Sulfide-Sodium Acrylate Copolymer (hereinafter abbreviated as P(MVS-A)) Methyl vinyl sulfide (hereinafter abbreviated as P(MVS-A)) was placed in a four-bottle flask equipped with a reflux condenser, a thermometer, an agitator, and a nitrogen inlet tube. MV below
S) and methyl acrylate (hereinafter abbreviated as MθA) were charged in the molar ratio shown in Table 2, BPO was used as the polymerization initiator in the molar ratio shown in Table 2, and BPO was used as the chain transfer agent in the molar ratio shown in Table 2. Toluene was added as a solvent, and the solution was mixed at 60° C. for 5 hours under a nitrogen stream. The reaction solution was then cooled and poured into Inuyama 1: hexane with stirring to precipitate a copolymer. ft4't' of 11t radish copolymer in a small amount of chloroform
A methylvinyl sulfide-methyl acrylate copolymer was obtained by purifying the copolymer by reprecipitation in 10 times the volume of hexane.The Mn of the obtained copolymer was measured by the vpo method, and the necessary functional groups were determined by The monomer composition ratio in the polymer was calculated from the elemental analysis values.Next, the MVS7MeA copolymer was reacted with 1.5 times equivalent of 20% sodium hydroxide aqueous solution in an autoclave at 150°C for 3 days. Sodium salt!1
is.

Synthesis Example 3 Vinyl alcohol-sodium acrylate copolymer (
Synthesis of P(VA-A)) Polymerization was carried out at 70° C. for 5 hours using vinyl acetate (hereinafter referred to as VAc) and methyl acrylate (MeA) in the same manner as in Synthesis Example 2. The obtained copolymer was treated in the same manner as in Synthesis Example 2 to obtain P.
(V'A-A) was obtained. The molar ratio etc. are shown in Table-3.

Example 1 Cleaning power test d2. A cotton face stain cloth was used as the naturally contaminated cloth. Judgment was made using the Sch θffe pairwise comparison method (four sheets of paper turned over, left and right), and the naked eye was used for comparison. Each time, commercially available sodium tripolyphosphate and sodium oxadiacetate were also used.

The cleaning conditions and detergent composition are as follows.

1) Washing detergent rate: 0.12% Washing temperature: 25°C Washing time: 8 minutes
1: 60 Water used: 3°DH tap water 11) Rinse water temperature: 25°C Rinse time using washing machine: 3 minutes 111) Detergent composition trial builder (Table 4) 25% Sodium silica No. 2 5% Anhydrous sodium carbonate 3 % Carboxymethyl cellulose (OMO) o, s % Anhydrous sodium sulfate 46.5% The results of the detergency test are shown in Table 4.

In the same evaluation, the effect of sodium oxadiacetate was 0 and the effect of sodium tripolyphosphate was 10.

Table 4 Example 2 A 50 m #beak mold with rotor removed, 10 m1 of the sample builder shown in Table 5 was removed, and this was 1, OX 10
-' Dissolved in 50 m of aqueous calcium solution, added 4.0 M aqueous potassium chloride solution as an ionic strength adjusting agent, and adjusted the ionic strength to μ = 0.08.
Stir once in a constant temperature bath at ℃, and measure the calcium ion strength after 10 minutes using a calcium ion electrode (I-Rion Co., Ltd. MODE).
L 93-20) is used to
f of calcium ions measured using Nami Kogyo KK Kogyo M-2og) and sequestered by sample builder 100t.
Indicated by &U.

The results are shown in Table-5.

Actual h10 example 5 <Evaluation of manganese dioxide dispersion power> Manganese dioxide 1.
Of: Take 50ml of a 0.05% aqueous solution of the sample builder shown in A-5, shake it up and down 100 times, and then cool it at 25°C.
Leave it in a constant temperature bath for 4 hours. Next, 15 g 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. The dispersion power was expressed by the number of manganese dioxide suspended in 100 m of suspension. See the results
-5.

Table-5 Example 4 Using a, 1y/no aqueous solutions of each sample shown in Table-6,
The biodegradability test was carried out in accordance with J-K5KO102.

The results are shown in Table-6.

Table 6 Example 5 In order to examine the scale prevention effect of the sequestering agent of the present invention, a sequestering agent (P(MVS-a)-7sxo(
s, 2), p(uvg-A)-7sxo(1s, 9),
p(vA-A)-3960(24,6)) and 1
I drove it for 8 years.

As a result, no scale was observed.

Applicant's agent: Kaoru Utsuya

Claims (1)

[Claims] At least one incorporated monomer unit consisting of alkyl bi, = ether, alkyl vinyl sulfide ((both B and L have 3 or less carbon atoms in the alkyl group) and vinyl alcohol, acrylic acid and methacrylic acid) A gold plate ion polishing agent containing a copolymer containing at least one well-selected monomer unit and having an average molecular weight of 500 to 100,0 rIO, or an alkali metal or amine salt thereof as an active ingredient.