JP3375798B2 - Aqueous iron dispersant - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel aqueous iron dispersant. More specifically, the present invention, in a water system such as a boiler system, a cooling water system, a water supply system, a dust collection system, an iron oxide or iron hydroxide produced by corrosion of a steel material, an iron material or the like constituting the system, a water system from the surrounding environment. Iron oxides or iron hydroxides that are mixed in the water are deposited on or adhere to equipment such as heat exchangers and condensers or pipes that make up the water system, resulting in problems such as reduced efficiency of the heat exchangers and pipes. Prevents the flow rate of water from decreasing in the heat exchanger and the local corrosion (pitting corrosion) of the metal at the bottom of the iron oxide or iron hydroxide adhesion by dispersing the iron components such as iron oxide or iron hydroxide. The present invention relates to an aqueous iron-based dispersant.

[0002]

2. Description of the Related Art Conventionally, in a boiler system, a cooling water system, a water supply system, a dust collection system, etc., a polymerized phosphate or carboxylic acid system is used for the purpose of preventing damage caused by the deposition or adhesion of iron oxide or iron hydroxide. Polymer compounds are used. However, the dispersing effect of these compounds on iron oxide and iron hydroxide is insufficient, and their deposition or adhesion cannot be completely prevented. Although polymerized phosphate is effective, it has been a problem that various secondary obstacles occur. For example, polymerized phosphate is easily hydrolyzed to orthophosphate, which reduces its dispersive power. In addition, since the wastewater containing phosphorus causes a problem of eutrophication in closed waters such as lakes and inland seas, the amount of the chemical containing phosphorus must be limited. Also,
The carboxylic acid polymer compound forms an insoluble salt when the concentration of the polyvalent metal ion in water is increased, and the carboxylic acid polymer compound itself precipitates and thus does not act effectively. In particular, when the concentration of calcium ions increases, the water becomes cloudy due to the formation of insoluble salts,
A precipitate forms.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a water-based iron dispersant which does not contain phosphorus, does not form polyvalent metal ions and insoluble salts, has an excellent dispersing effect, and maintains the effect. It was made for the purpose of doing.

[0004]

As a result of intensive studies to solve the above problems, the present inventors have found that a copolymer of conjugated dienesulfonic acid and (meth) acrylic acid having a specific structure is They have found that they have an excellent dispersing effect on aqueous iron oxide and iron hydroxide, and have completed the present invention based on this finding. That is, the present invention provides (1) a conjugated dienesulfonic acid represented by the general formula [1] and / or a salt thereof.

[Chemical 3] (However, in the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are
Hydrogen, a methyl group or —SO ₃ X ¹ , and R ^{1 to} R ⁶
At least one of R ^{1 to} R ⁶ is a methyl group.
SO ₃ X ¹ , where X ¹ is hydrogen, a metal corresponding to monovalence, or an unsubstituted or organic group-monosubstituted ammonium group. ), And (meth) acrylic acid represented by the general formula [2] and / or a salt thereof.

[Chemical 4] (In the formula, R ⁷ is hydrogen or a methyl group, X ² is hydrogen, a metal corresponding to monovalent or an unsubstituted or organic group-monosubstituted ammonium group.) The water-based iron dispersant to be used, (2) the copolymer is a conjugated diene sulfonic acid and / or a salt thereof in a unit of 5 to 50 mol% and a (meth) acrylic acid and / or a salt thereof in a unit of 50.
The weight average molecular weight of the water-based iron dispersant according to item (1) and the copolymer (3) is 5 to 95 mol%.
The water-based iron dispersant according to item (1) or (2), which is 00 to 300,000.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The aqueous iron dispersant of the present invention is a conjugated dienesulfonic acid represented by the general formula [1] and / or a salt thereof, and a (meth) represented by the general formula [2]. It contains a copolymer synthesized from acrylic acid and / or its salt.

[Chemical 5] In the general formula [1], R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are hydrogen, a methyl group or —SO ₃ X ¹ , and
At least one of R ^{1 to} R ⁶ is a methyl group, at least one of R ^{1 to} R ⁶ is —SO ₃ X ¹ , and X ¹ is hydrogen, a metal corresponding to monovalent or an unsubstituted or organic group. It is a mono-substituted ammonium group. In addition, in the general formula [2], R ⁷ is hydrogen or a methyl group, and X ² is hydrogen, a metal corresponding to monovalence, or an unsubstituted or organic group-monosubstituted ammonium group. A metal equivalent to monovalent is a metal itself such as Na or K when the metal is monovalent like an alkali metal, and is a divalent metal like an alkaline earth metal. Is a metal that is virtually expressed like Mg _1/2 , Ca _1/2, etc. If the metal is trivalent like aluminum, it is virtually expressed like Al _1/3. It is a metal. The organic group mono-substituted ammonium group is an ammonium group formed by the reaction of —SO ₃ H and a primary amine, and examples of the primary amine which gives such an organic group mono-substituted ammonium group include methylamine. , Ethylamine, propylamine, isopropylamine, butylamine, isobutylamine, sec-butylamine, tert-
Examples thereof include butylamine, pentylamine, hexylamine, cyclohexylamine, benzylamine and monoethanolamine. In the aqueous iron dispersant of the present invention, X ¹ and X ² are preferably alkali metals, and X ¹ and X ² are particularly preferably sodium.

Examples of the conjugated dienesulfonic acid represented by the general formula [1] include 2-methyl-1,3-butadiene-1-sulfonic acid and 2-methyl-1,3-butadiene-3-sulfonic acid. , 2-methyl-1,3-butadiene-
4-sulfonic acid, 1,3-pentadiene-1-sulfonic acid, 1,3-pentadiene-2-sulfonic acid, 1,3-pentadiene-3-sulfonic acid, 1,3-pentadiene-
4-sulfonic acid, 2,3-dimethylbutadiene-1-sulfonic acid, 2-methyl-1,3-pentadiene-4-sulfonic acid, 3-methyl-1,3-pentadiene-1-sulfonic acid, 2-methyl -1,3-butadiene-1,3-disulfonic acid, 2-methyl-1,3-butadiene-1,4-
Examples thereof include disulfonic acid. General formula [2]
Examples of the (meth) acrylic acid represented by are acrylic acid and methacrylic acid, and acrylic acid can be preferably used in the water-based iron dispersant of the present invention. There is no particular limitation on the method of copolymerizing the conjugated dienesulfonic acid represented by the general formula [1] and / or its salt with the (meth) acrylic acid represented by the general formula [2] and / or its salt. Can be copolymerized by a known polymerization method. Both the monomer represented by the general formula [1] and the monomer represented by the general formula [2] are water-soluble, and the copolymer obtained by copolymerizing the both is also water-soluble. Solution polymerization as a medium can be preferably used. Solution polymerization using water as a medium can be carried out by dissolving a predetermined monomer in water, replacing the atmosphere with nitrogen, adding a water-soluble polymerization initiator, and heating.

In the aqueous iron dispersant of the present invention, the copolymer comprises 5 to 50 mol% of conjugated dienesulfonic acid and / or its salt unit and 50 to 50% of (meth) acrylic acid and / or its salt unit. It is preferably composed of 95 mol%, and the unit of the conjugated dienesulfonic acid and / or its salt is 10
More preferably, it is composed of ˜30 mol% and 70 to 90 mol% of units of (meth) acrylic acid and / or its salt. If the unit of the conjugated diene sulfonic acid and / or its salt in the copolymer is less than 5 mol% or more than 50 mol%, the dispersion effect of iron oxide and iron hydroxide in the aqueous system may decrease. is there. If the unit of (meth) acrylic acid and / or its salt in the copolymer is less than 50 mol% or more than 95 mol%, the dispersion effect of iron oxide and iron hydroxide in the aqueous system may decrease. There is. In the water-based iron dispersant of the present invention, the copolymer is a unit of the conjugated diene sulfonic acid represented by the general formula [1] and / or a salt thereof, and a unit represented by the general formula [2] (meth). In addition to the units of acrylic acid and / or its salt, a copolymer having further other monomer units can be used. Such a copolymer is obtained by copolymerizing a monomer represented by the general formula [1], a monomer represented by the general formula [2] and a monomer copolymerizable therewith by a known method. It can be obtained by polymerizing. Examples of the monomer represented by the general formula [1] and the monomer copolymerizable with the monomer represented by the general formula [2] include 2-acrylamido-2-methylpropanesulfonic acid and 3 -Allyloxy-2-hydroxypropanesulfonic acid, vinylphosphonic acid, acid phosphooxyethyl methacrylate, acid phosphooxyethyl acrylate, acid phosphooxypolyoxyethylene glycol monomethacrylate, (meth) acrylamide, (meth) acrylonitrile, (meth) acrylic Methyl acid, 2-hydroxyethyl (meth) acrylate,
Examples thereof include glycidyl (meth) acrylate, N-methylol (meth) acrylamide, maleic acid, maleic anhydride, styrene, α-methylstyrene, vinyltoluene, p-methylstyrene and vinyl acetate.
In the aqueous iron dispersant of the present invention, the weight average molecular weight of the copolymer is preferably 500 to 300,000, more preferably 5,000 to 50,000. When the weight average molecular weight of the copolymer is less than 500,
There is a risk that the effect of dispersing iron oxide and iron hydroxide in the water system may be reduced. The weight average molecular weight of the copolymer is 300,0
If it exceeds 00, the viscosity may be too high and handling may be difficult.

When the aqueous iron dispersant of the present invention is used, the concentration to be added to the aqueous system can be appropriately selected depending on the concentration of iron oxide or iron hydroxide in the water. The amount is 0.1 to 1,000 mg / liter, and in many cases, the solid content of the copolymer is 1 to 1 mg.
A sufficient dispersion effect can be exhibited by the addition of 00 mg / liter. The water-based iron dispersant of the present invention is a boiler system, a cooling water system, a water supply system such as industrial water, a dust collection system, a drainage system such as the steel industry, and the like, the deposition of iron oxide or iron hydroxide,
It is added to prevent problems caused by adhesion. The addition method is not particularly limited, and it may be added to the water system at once, or may be injected intermittently or continuously. The water-based iron dispersant of the present invention may be mixed with a known water treatment agent before use. Also,
The water-based iron dispersant of the present invention and a known water treatment agent can be individually added to the water system and used in combination. Examples of known water treatment agents that can be used in combination with the water-based iron dispersant of the present invention include metal corrosion inhibitors, scale inhibitors, bactericides (slime inhibitors), acids and alkaline agents. it can. Examples of the metal corrosion inhibitor include orthophosphate, polymerized phosphate, phosphate ester, phosphonate, zinc salt, nickel salt, molybdate, tungstate, oxycarboxylate, triazoles, amines. Kind of things can be mentioned. Examples of scale inhibitors include polyacrylic acid salts, polyacrylamides and partial hydrolysates thereof, maleic acid-based polymers, itaconic acid-based polymers, hydroxyethyl methacrylate, hydroxyallyloxypropane sulfonic acid, acrylamide-2.
Examples thereof include acrylic acid-based two-component copolymers containing methylpropanesulfonic acid and the like. Examples of the bactericide (antislime agent) include chlorine gas, sodium and calcium hypochlorite, chlorine agents such as chlorinated sodium isocyanurate, inorganic or organic bromine agents, organic nitrogen-sulfur agents, and quaternary ammonium. Examples thereof include salt.

[0009]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples. Example 1 In a 500 ml conical beaker, add 450 ml of demineralized water,
An iron dispersant containing a sodium salt of an isoprenesulfonic acid / acrylic acid (molar ratio 15/85) copolymer having a weight average molecular weight of 11,000 was 10.0 m as a solid content.
g was added. Calcium hardness 2
50 mg CaCO ₃ / liter, magnesium hardness 100 m
gCaCO ₃ / liter, M-alkalinity 250mgCaC
O ₃ / liter, silica 100 mg SiO ₂ / liter, total iron 10.0 mg Fe / liter, sodium hydrogen carbonate solution, sodium silicate No. 3 solution, calcium chloride solution, magnesium sulfate solution, ferric chloride solution are added sequentially. Then, a 1 wt% sulfuric acid aqueous solution was added to adjust the pH to 8.8, and demineralized water was further added to bring the total amount to 500 ml. Seal the conical beaker with polyethylene film and
It was immersed in a constant temperature water bath whose temperature was adjusted to 0 ° C. and left for 20 hours. Then, the conical beaker was taken out and the dissolved iron concentration in the supernatant was measured and found to be 10.0 mg Fe / liter. If the effect of the dispersant is insufficient, the iron content in the test solution will be deposited as iron oxide hydrate or iron hydroxide.
The dissolved iron concentration in the supernatant decreases. In this embodiment,
The dissolved iron concentration in the supernatant was exactly the same as the total iron concentration in the original test liquid, and it can be seen that the iron content was completely dispersed and retained in water without any sedimentation. Examples 2 to 12 The same tests as in Example 1 were conducted using the iron content dispersants of the types and amounts shown in Table 1 below. In the preparation of the test solution, the final pH adjustment was 1% by weight sulfuric acid solution or 1% by weight.
It was carried out by adding an aqueous solution of sodium hydroxide. The test results are shown in Table 1-1. Comparative Examples 1-3 Using sodium hexametaphosphate as an iron dispersant,
The same test as in Example 1 was conducted. In the preparation of the test solution, the final pH adjustment was performed by adding a 1 wt% sulfuric acid aqueous solution. The test results are shown in Table 1-2. Comparative Examples 4 to 5 The same test as in Example 1 was conducted using sodium polyacrylate having a weight average molecular weight of 5,000 as the iron dispersant. In the preparation of test solution, the final pH adjustment is 1
It was carried out by adding a weight% sulfuric acid aqueous solution. First test result
It shows in Table-2. Comparative Example 6 The same operation as in Example 1 was performed except that the iron dispersant was not added. In the preparation of the test solution, the final pH adjustment was performed by adding a 1 wt% sulfuric acid aqueous solution. The test results are shown in Table 1-2.

[0010]

[Table 1]

[0011]

[Table 2]

From the results shown in Table 1-1, the aqueous iron dispersants of Examples 1 to 12 of the present invention exhibited an excellent dispersing effect with respect to iron oxide or iron hydroxide and had a solid content of 7%. .5
10mgFe by adding ~ 10mg / l
It can be seen that the iron content of 1 / liter can be completely dispersed and held in water without being deposited. On the other hand, from the results of Comparative Examples 1 to 5, iron dispersants such as sodium hexametaphosphate and sodium polyacrylate, which have been conventionally used, have a solid concentration of 10 mg / liter. It can be seen that the iron content of 10 mg Fe / liter cannot be retained in the water and a considerable amount of iron is deposited. Further, in Comparative Example 6 in which no iron dispersant is used, up to 96% by weight of iron in water is deposited.

[0013]

The water-based iron dispersant of the present invention prevents iron oxide or iron hydroxide from depositing or adhering to heat exchangers, heat transfer pipes, pipes, etc. constituting the water system in a boiler system, a cooling water system or the like. It is possible to prevent problems such as a decrease in the thermal efficiency of the system and a decrease in the flow rate of water.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C02F 5/00 620 C02F 5/00 620D (72) Inventor Katsuhiro Ishikawa 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic rubber stock In-company (56) References JP-A-6-63590 (JP, A) JP-B-5-8045 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) C02F 5/00- 5/14 C23F 11/00-11/18 C23F 14/00-17/00 B01F 17/00-17/56 C09K 3/00 C11D 7/22-7/46

Claims (3)

(57) [Claims] 1. A conjugated diene sulfonic acid represented by the general formula [1] and / or a salt thereof: (However, in the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are
Hydrogen, a methyl group or —SO ₃ X ¹ , and R ^{1 to} R ⁶
At least one of R ^{1 to} R ⁶ is a methyl group.
SO ₃ X ¹ , where X ¹ is hydrogen, a metal corresponding to monovalence, or an unsubstituted or organic group-monosubstituted ammonium group. ), And (meth) acrylic acid represented by the general formula [2] and / or a salt thereof: (In the formula, R ⁷ is hydrogen or a methyl group, X ² is hydrogen, a metal corresponding to monovalent or an unsubstituted or organic group-monosubstituted ammonium group.) Aqueous iron dispersant. 2. The copolymer is a conjugated diene sulfonic acid and / or
The aqueous iron dispersant according to claim 1, which is composed of 5 to 50 mol% of a salt unit thereof and 50 to 95 mol% of (meth) acrylic acid and / or a salt unit thereof. 3. The weight average molecular weight of the copolymer is 500 to 3
The water-based iron dispersant according to claim 1 or 2, which is 00000.