JP2000007734A - Water-soluble copolymer (salt) and scale inhibitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-soluble copolymer (salt) having a better scale-inhibiting effect than conventional ones, and particularly exhibiting an excellent scale-inhibiting effect even on silica-based scales. . (A) a structural unit having a sulfonic acid group,
A water-soluble copolymer (salt) containing (b) a structural unit having a carboxylic acid group and (c) a structural unit having a polyalkylene oxide group as a repeating structural unit, and having a weight average molecular weight of more than 50,000 to 3,000,000 or less. .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a water-soluble copolymer (salt) capable of controlling the adhesion problem of an aqueous scale, particularly a silica-based scale, and a water-soluble copolymer (salt). It relates to a scale inhibitor as an active ingredient.

[0002]

2. Description of the Related Art Scales, such as calcium salts, magnesium salts, and silica, are formed on a vessel wall, such as a cooling water system or a boiler water system, which comes into contact with water, particularly on an electrically heated surface. Particularly, in the open-circulation type cooling water system, from the viewpoint of resource saving and energy saving, when performing the high concentration operation by reducing the disposal (blowing) of the cooling water outside the system, the dissolved salts are highly concentrated and the solubility is low. Calcium salts, magnesium salts, silica, etc. are scaled. Among them, silica has particularly low solubility, and is scaled at about 100 to 150 mg / L.

Heretofore, poly (meth) acrylates (for example, Japanese Patent Publication No. 49-149) have been used as scale inhibitors for preventing or removing such silica-based scale.
No. 30914), and a carboxylic acid / sulfonic acid / polyalkylene oxide copolymer (salt) having a weight average molecular weight of 50,000 or less and a specific low molecular weight compound (for example,
-Phosphonobutane-1,2,4-tricarboxylic acid) (for example, JP-A-5-104093).

Some of the conventional scale inhibitors containing a high molecular compound as an active ingredient have excellent scale preventing effects in a limited field of application, but are not always satisfactory. In particular, in the case of performing a high concentration operation in an open circulation cooling water system, the conventional technology is not satisfactory with respect to prevention of formation of silica-based scale, and a scale inhibitor having a higher scale prevention effect is demanded.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the conventional problems, and has an excellent scale preventing effect as compared with the conventional one. An object of the present invention is to provide a water-soluble copolymer (salt) having the following formula:

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the problems of the above-mentioned scale inhibitor, and as a result, have found that the following (1) and (2) are simultaneously satisfied. It has been found that a water-soluble copolymer (salt) having a high molecular weight has a very excellent scale-inhibiting effect without using a specific low-molecular-weight compound, and based on the findings, the present invention was completed. Was. (1) Water-soluble copolymer (salt) containing sulfonic acid group, carboxylic acid group and polyalkylene oxide group as essential components (2) Water-soluble copolymer (salt) having a weight average molecular weight exceeding 50,000

That is, the present invention comprises (a) a constitutional unit having a sulfonic acid group, (b) a constitutional unit having a carboxylic acid group, and (c) a constitutional unit having a polyalkylene oxide group as repeating constitutional units. The present invention provides a water-soluble copolymer (salt) having an average molecular weight of more than 50,000 and not more than 3,000,000. Here, the water-soluble copolymer (salt) includes (a) a monomer having a sulfonic acid group and having a polymerizable double bond (hereinafter referred to as “component (a)” or “(a) sulfonic acid group”). ), (B)
A carboxylic acid group-containing monomer having a polymerizable double bond (hereinafter also referred to as “(b) component” or “(b) carboxylic acid group-containing monomer”) and (c) a polyalkylene oxide group By polymerizing a monomer component mainly composed of a monomer having a polymerizable double bond (hereinafter also referred to as “(c) component” or “(c) polyalkylene oxide group-containing monomer”) Those obtained are preferred. Also,
The present invention provides a scale inhibitor containing the above water-soluble copolymer (salt) as an active ingredient. Here, the above-mentioned scale inhibitor has a high effect of preventing silica-based scale, and is particularly effective for silica-based scale.
Next, the present invention provides (a) a sulfonic acid group-containing monomer,
(B) polymerizing a monomer component mainly composed of a carboxylic acid group-containing monomer and a monomer having a polymerizable double bond containing a (c) -1 polyalkylene oxide group, or During or after polymerization of the monomer component having the component (b) and the component (b) as a main component,
(C) -2 a polyalkylene oxide is introduced or the above-mentioned component (a), component (b) and an active hydrogen-containing monomer [where active hydrogen is contained in component (a) and / or (b)] During or after the polymerization of the monomer component containing (c) -3 alkylene oxide to introduce a polyalkylene oxide group, or to contain a carboxylic acid group. The method for producing a water-soluble copolymer (salt), wherein a sulfonic acid group and a polyalkylene oxide group are introduced after the production of the high molecular weight product, and the weight average molecular weight is adjusted to be more than 50,000 to 3,000,000 or less. To provide. Here, the above (a) / (b)
/ (C) [(c) -1, (c) -2 or (c)-
3] The weight ratio of (a) / (b) / (c) is 2 to 50/4
0 to 93/5 to 50 [(a) + (b) + (c)
= 100% by weight]. The weight ratio of (a) / (b) / (c) [(c) -1, (c) -2 or (c) -3] is 5/45/45/87 /
When the value is 8 to 45 [(a) + (b) + (c) = 100% by weight], the A value represented by the following formula is 25.
It is preferable that the ratio is more than 3,000,000. A = {(Mw / 10,000) ⁴ × [% by weight of (c) in (a) to (c)]} / 1,000 (wherein Mw represents a weight average molecular weight) The polymerization degree of the polyalkylene oxide is preferably 2 to 50.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, even if the above (1) is satisfied, if (2) is not satisfied, the scale prevention effect will be poor. Further, even if the above (2) is satisfied, if any of the essential components of (1) is missing, the effect of preventing scale is inferior. It is surprising that such a limitation of the functional group and an increase in the molecular weight produce a synergistically superior scale-preventing effect, and no one has found this finding to date.

In the water-soluble copolymer (salt) of the present invention,
(A) The sulfonic acid group-containing monomer constituting the structural unit having a sulfonic acid group is not particularly limited as long as it is a monomer having a sulfonic acid group and having a polymerizable double bond. Conjugated diene sulfonic acids represented by the general formula (I) (for example, 2-methyl-1,3-butadiene-
1-sulfonic acid) (Wherein, R ^{1 to} R ⁶ are a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 20 carbon atoms or —SO ₃ X, wherein X is a hydrogen atom, a metal atom, ammonium Or at least one of R ^{1 to} R ⁶ is —SO ₃ X) or the following general formula (II)
(E.g., 3-allyloxy-2-hydroxypropanesulfonic acid, 3-methallyloxy-2-hydroxypropanesulfonic acid)

[0010]

Embedded image

[Wherein R ⁷ is a hydrogen atom or a carbon atom having 1 to
8 represents an alkyl group, ad is the same or different, and 0
Or an integer of 1 to 100 (however, a + b + c +
d = 0 to 100), (OC ₂ H ₄ ) units and (OC
₃ H ₆ ) units are bonded in any order, Y and Z are sulfonic acid groups or hydroxyl groups, and at least one of Y and Z is a sulfonic acid group. In addition, when a + b ≧ 2 or c + d ≧ 2, the monomer represented by the general formula (II) is (a) a sulfonic acid group-containing monomer and (c) a polyalkylene of the present invention. And a (meth) acrylamide-
2-methylpropanesulfonic acid, 2-hydroxy-3-
Examples include acrylamide propane sulfonic acid, styrene sulfonic acid, methallyl sulfonic acid, vinyl sulfonic acid, allyl sulfonic acid, isoamylene sulfonic acid, and salts thereof. Preferably, 2-methyl-1,3
-Butadiene-1-sulfonic acid, (meth) acrylamide-2-methylpropanesulfonic acid, 3- (meth) allyloxy-2-hydroxypropanesulfonic acid, styrenesulfonic acid, or salts thereof. These (a) sulfone group-containing monomers can be used alone or in combination of two or more.

The amount of the sulfonic acid group-containing monomer (a) used in the structural units (a) to (c), that is, (a) to (c)
It is preferably from 2 to 50% by weight, more preferably from 5 to 45% by weight, particularly preferably from 5 to 35% by weight, in the monomer component containing the component (c) as a main component. If the amount is less than 2% by weight, the resulting copolymer (salt) does not have sufficient scale-preventing performance. On the other hand, if it exceeds 50% by weight, these properties may not be satisfied.

The (b) carboxylic acid group-containing monomer constituting the carboxylic acid group-containing structural unit is not particularly limited as long as it is a monomer having a carboxylic acid group and having a polymerizable double bond. Is, for example, maleic anhydride, acrylic acid, methacrylic acid, α-haloacrylic acid, maleic acid, itaconic acid, vinyl acetic acid, allyl acetic acid, fumaric acid,
Examples include phosphinocarboxylic acid, β-carboxylic acid, and salts thereof. Preferably, acrylic acid, methacrylic acid, or salts thereof are good. These carboxylic acid group-containing monomers can be used alone or in combination of two or more. (B)
The amount of the carboxylic acid group-containing monomer to be used is preferably 40 to 93 in the structural units (a) to (c), that is, in the monomer component containing the components (a) to (c) as a main component. % By weight, more preferably 45 to 87% by weight, particularly preferably 50 to 87% by weight.
82% by weight. If the amount is less than 40% by weight, the resulting copolymer (salt) does not have sufficient anti-scaling properties.
When the content exceeds 3% by weight, these properties may not be satisfied.

Further, the water-soluble copolymer (salt) of the present invention
Examples of the method for introducing (c) a structural unit having a polyalkylene oxide group include: (a) a sulfonic acid group-containing monomer, (b) a carboxylic acid group-containing monomer, and (c) -1 Polymerizing the polyalkylene oxide group-containing monomer, during or after the polymerization of the components (a) and (b),
The (c) -2 polyalkylene oxide is graft-introduced by an esterification reaction. The above components (a) and (b) and an active hydrogen-containing monomer [where the components (a) and / or (b) During or after polymerization, (c) -3 alkylene oxide is reacted to introduce a polyalkylene oxide group, or a high molecular weight containing a base carboxylic acid group is included. After the body is produced, a sulfonic acid group and a polyalkylene oxide group are introduced.

When the above (c) -1 polyalkylene oxide group-containing monomer is polymerized, the component (c) -1 may be, for example, (alkoxy) polyethylene glycol mono (meth) acrylate, (alkoxy) polypropylene Glycol mono (meth) acrylate, (alkoxy) polyethylene glycol polypropylene glycol mono (meth) acrylate, (alkoxy) polyethylene glycol polytetramethylene glycol mono (meth) acrylate, (alkoxy) polypropylene glycol polytetramethylene glycol mono (meth)
Acrylate and the like. Preferred are (alkoxy) polyethylene glycol mono (meth) acrylate, (alkoxy) polypropylene glycol mono (meth) acrylate, and (alkoxy) polyethylene glycol polypropylene glycol mono (meth) acrylate. These (c) -1 polyalkylene oxide group-containing monomers can be used alone or
Mixtures of more than one species can be used.

When a polyalkylene oxide group is introduced during or after the polymerization, (c) -2 a polyalkylene oxide may be introduced by an ester reaction, or a monomer having an active hydrogen [ , (A) and / or (b) a component containing an active hydrogen] during or after the polymerization of (c) -3 alkylene oxide.

Here, the (c) -2 polyalkylene oxide used when introduced by an ester reaction is:
For example, (alkoxy) polyethylene glycol, (alkoxy) polypropylene glycol, (alkoxy)
Polyethylene glycol, polypropylene glycol and the like can be mentioned. During the polymerization, the polyalkylene oxide used for graft-introducing the polyalkylene oxide after the polymerization may be used alone or may be used alone.
Mixtures of more than one species can be used.

In the case where a polyalkylene oxide group is introduced by reacting (c) -3 alkylene oxide during or after polymerization of a monomer having active hydrogen, the monomer having active hydrogen may be: For example, in addition to the unsaturated (meth) allyl ether monomer represented by the general formula (II) (at least one of Y and Z is a hydroxyl group), these monomers other than the components (a) to (c) Among other monomers copolymerizable with (see below), unsaturated alcohols,
Hydroxy group-containing (meth) acrylic esters, (N-substituted) (meth) acrylamides, and the like. Further, as the (c) -3 alkylene oxide to be used,
For example, ethylene oxide, propylene oxide and the like can be mentioned. The ethylene / propylene (molar ratio) in the above alkylene oxide is preferably from 0 to 100/100.
０0, more preferably 50-100 / 50-0. The above-mentioned alkylene oxides can be used alone or in combination of two or more.

The above component (c) [(c) -1, (c) -2
Or (c) -3 component], the amount of (a) to (c)
Is preferably 5 to 50% by weight, more preferably 8 to 45% by weight, and particularly preferably 8 to 40% by weight in the structural unit (i), that is, in the components (a) to (c). If the amount is less than 5% by weight, the resulting copolymer (salt) does not have sufficient scale-preventing performance. On the other hand, if it exceeds 50% by weight, these properties may not be satisfied.

In the present invention, when component (c) is contained in component (a) and / or component (b), that is, in the final structure, a sulfonic acid group or a carboxylic acid group and a polyalkylene oxide group are formed. Same structural unit (d)
The amount (% by weight) of each component used in this case is 、% by weight of [(d) − (sulfonic acid group or carboxylic acid group + polyalkylene oxide group)].
Is added to the weight% of the sulfonic acid group or carboxylic acid group and the polyalkylene oxide group, respectively.

Furthermore, when a sulfonic acid group and a polyalkylene oxide group are introduced after the production of a carboxylic acid group-containing high molecular weight compound as a base, the carboxylic acid group-containing high molecular weight compound may be, for example, a sulfonable constituent. Examples include a monomer comprising a unit, a copolymer comprising a carboxylic acid group-containing monomer and an active hydrogen-containing monomer. Here, as a monomer containing a structural unit capable of being sulfonated,
For example, a polymerizable monomer having a benzene ring such as styrene may be used. Examples of the sulfonating agent used for introducing a sulfonic acid group include concentrated sulfuric acid, fuming sulfuric acid, and sulfuric anhydride. Examples of the carboxylic acid group-containing monomer include those similar to the component (b). Further, examples of the method for introducing a polyalkylene oxide group include the above-mentioned methods and the like. Also in the case of the above, the ratio of the sulfonic acid group-containing structural unit, the carboxylic acid group-containing structural unit and the polyalkylene oxide group-containing structural unit is the same as that of the above structural units (a) to (c), that is, the components (a) to (c) Same as each usage ratio.

The water-soluble copolymer (salt) of the present invention comprises
(A) a structural unit having a sulfonic acid group is 5 to 45% by weight in all repeating structural units, (b) a structural unit having a carboxylic acid group is 45 to 87% by weight in all repeating structural units,
(C) 8 to 45% by weight of the structural unit having a polyalkylene oxide group in all the repeating structural units [provided that (a)
+ (B) + (c) = 100% by weight], it is preferable that the A value represented by the following formula exceeds 25 and is 3,000,000 or less. A = {(Mw / 10,000) ⁴ × [% by weight of (c) in (a) to (c)]} / 1,000 That is, as described above, the water-soluble copolymer of the present invention ( When the amount of the polyalkylene oxide group in the salt is small, it is necessary to further increase its weight average molecular weight (Mw). In this case, if the A value is 25 or less, the scale prevention performance may not be sufficient. On the other hand, if the A value exceeds 3 million, the scale prevention performance may not be sufficient.

The length (degree of polymerization) of these polyalkylene oxides is preferably 2 to 50, and more preferably 2 to 30. When it is less than 2, the scale prevention performance is not sufficient. On the other hand, when it exceeds 50, this performance may not be satisfied similarly.

In the water-soluble copolymer (salt) of the present invention,
In addition to the components (a) to (c), it is also possible to copolymerize one or more other monomers copolymerizable therewith. Other copolymerizable monomers include, for example, unsaturated alcohols such as vinyl alcohol, allyl alcohol, methyl vinyl alcohol, ethyl vinyl alcohol, and vinyl glycolic acid, and hydroxymethyl (meth)
Hydroxyl-containing (meth) such as acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, glycerol mono (meth) acrylate, glycerol di (meth) acrylate, butanediol (meth) acrylate, and hexanediol (meth) acrylate (N-substituted) (meth) acrylamides such as acrylic acid esters, (meth) acrylamide, N-alkylacrylamide, aromatic compounds such as styrene, α-methylstyrene, vinyltoluene, p-methylstyrene, (meth) Alkyl (meth) acrylates such as methyl acrylate, ethyl (meth) acrylate, octyl (meth) acrylate, butadiene,
Aliphatic conjugated dienes such as isoprene, 2-chloro-1,3-butadiene and 1-chloro-1,3-butadiene;
Examples thereof include vinyl cyanide compounds such as (meth) acrylonitrile. When these other monomers are copolymerized, 30% by weight of all the monomer components used in the copolymerization are used.
The following is preferred.

A sulfonic acid group provided in the present invention,
A method for producing a water-soluble copolymer (salt) containing a carboxylic acid group and a polyalkylene oxide group is, for example, as follows. That is, a sulfonic acid group-containing monomer, a carboxylic acid group-containing monomer, and a polyalkylene oxide group-containing monomer are converted into a polymerization initiator, for example, a known radical such as hydrogen peroxide, sodium persulfate, or potassium persulfate. A copolymer (salt) can be produced by performing a polymerization reaction at a reaction temperature, usually 20 to 200 ° C, preferably 40 to 150 ° C, for 0.1 to 20 hours in the presence of a polymerization initiator. Further, a sulfonic acid group-containing monomer and a carboxylic acid group-containing monomer are reacted with a polymerization initiator such as sodium persulfate or a known radical polymerization initiator such as potassium persulfate at a reaction temperature of usually 20%. ~ 200 ° C, preferably 40
The polyalkylene oxide can be graft-introduced by an ester reaction after the copolymer is produced by carrying out a polymerization reaction at 0.1 to 150 ° C. for 0.1 to 20 hours or during the polymerization. Furthermore, a sulfonic acid group-containing monomer, a carboxylic acid group-containing monomer and an active hydrogen-containing monomer are polymerized with a polymerization initiator, for example, in the presence of a known radical polymerization initiator such as sodium persulfate and potassium persulfate. , Reaction temperature,
Usually, after a polymerization reaction is performed at 20 to 200 ° C., preferably 40 to 150 ° C. for 0.1 to 20 hours to form a copolymer, or during polymerization, an alkylene oxide is reacted to introduce a polyalkylene oxide group. It can also be manufactured. Further, there is also a method in which a sulfonic acid group and a polyalkylene oxide group are introduced after producing a carboxylic acid group-containing high molecular weight substance as a base. The reaction conditions in this case include a monomer containing a sulfonable structural unit, a carboxylic acid group-containing monomer and an active hydrogen-containing monomer (a monomer containing a sulfonable structural unit and / or a carboxylic acid-containing monomer). (Including the case where active hydrogen is contained in the group-containing monomer)
Is polymerized by the above-described method to produce a copolymer, and then a sulfonic acid group is produced by a sulfonation reaction,
It can be produced by introducing a polyalkylene oxide group according to the above-mentioned methods.

In the above case, the molecular weight of the obtained copolymer (salt) can be adjusted by controlling the reaction conditions, in particular, the amount of the polymerization / reaction solvent, the kind and amount of the polymerization initiator, the reaction temperature and the like. it can. The polymer structure of the water-soluble copolymer (salt) of the present invention thus obtained has a random structure or a block structure, but preferably has a random structure.

In each of the above reactions, a polymerization / reaction solvent can be used to smoothly carry out the reaction.
As the reaction solvent, water, an organic solvent, a mixture of an organic solvent miscible with water and water, or the like can be used.
Specific examples of the organic solvent include, for example, methanol,
Ethanol, propyl alcohol, alcohols such as butanol, benzene, toluene, xylene, aromatic hydrocarbons such as ethylbenzene, n-pentane, n-hexane, cyclohexane, n-heptane, aliphatic hydrocarbons such as octane, diethyl ether, Examples thereof include ethers such as tetrahydrofuran and 1,4-dioxane. The amount of the polymerization / reaction solvent used is 0 to 100 times the solid weight of the copolymer (salt) of the present invention. In the above reaction, when the polymerization of the monomer component is performed, the polymerization may be performed by charging the entire amount of the monomer component into the reactor at a time, or part or all of the monomer component may be sequentially added. Polymerization may be performed. In each of the above reactions, the amount of the radical polymerization initiator used is usually 0.001 to 20% by weight, preferably 0.01 to 10% by weight, based on all monomer components.

The water-soluble copolymer (salt) containing a sulfonic acid group, a carboxylic acid group and a polyalkylene oxide group provided in the present invention must have a weight average molecular weight of more than 50,000 and not more than 3,000,000. It is. When the weight average molecular weight is 50,000 or less, the scale prevention effect is poor, while
If it exceeds 3,000,000, there is a problem that its production becomes difficult.

The cationic species of the water-soluble copolymer (salt) thus obtained is not particularly limited, but in order to make it water-soluble, hydrogen, an alkali metal, an alkaline earth metal, etc. , Ammonium and amine are preferred. Examples of the alkali metal include sodium and potassium, examples of the alkaline earth metal include calcium and magnesium, and examples of the amine include methylamine, ethylamine, propylamine, dimethylamine, diethylamine, triethylamine, butylamine, dibutylamine, and tributylamine. And polyamines such as ethylenediamine, diethylenetriamine and triethylenetetramine, morpholine, piperidine and the like. Preferably, they are hydrogen, sodium, and potassium. These cation species can be exchanged with other cation species by various ion exchange techniques.

The water-soluble copolymer (salt) of the present invention can be used in an amount of 1,300 to 1,350 c
absorption of sulfonic acid group at m ⁻¹ , 1,700 to 1,8
Absorption of carboxylic acid group at 00 cm ⁻¹ ,
The absorption of the polyalkylene oxide group at 1,150 cm ^-1 and its structure can be confirmed by NMR measurement, and the composition ratio can be confirmed by measuring the amount of sulfonic acid, carboxylic acid and elemental analysis. Can be.

When the water-soluble copolymer (salt) of the present invention is used as a scale inhibitor, a sulfonic acid group, a carboxylic acid group and a polyalkylene oxide group are essential components,
In addition, as long as it contains a water-soluble copolymer (salt) having a weight-average molecular weight of more than 50,000 and not more than 3,000,000 as an active ingredient, it may further contain other components. The water-soluble copolymer (salt) of the present invention, as it is or dissolved in water or the like, is a boiler water system, a geothermal water system, an open or closed circulation cooling water system,
It is added to water systems such as a one-time cooling water system to prevent scale. The amount to be added varies depending on the metal ion and silica concentration of the target aqueous system, but generally ranges from 1 to 200 mg.
/ L. By adding the water-soluble copolymer (salt) of the present invention to the target aqueous system as a scale inhibitor, the formation of metal salt scales such as metal salts such as calcium salts and magnesium salts and silica scale can be suppressed and the formation of silica scales can be prevented. The scale that has been removed is removed to prevent scale, and the effect of preventing silica scale is particularly high. When the water-soluble copolymer (salt) of the present invention is used as a scale inhibitor, it can be used in combination with other scale inhibitors, corrosion inhibitors, slime inhibitors and the like.

[0032]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples. The percentages and parts in the examples are on a weight basis unless otherwise specified. Further, the weight average molecular weight (Mw) in the examples is obtained by converting the result determined by gel permeation chromatography (GPC) using a calibration curve prepared using sodium polystyrene sulfonate as a standard sample. Here, the measurement conditions of GPC are as follows. Column: G3000PWXL [manufactured by Tosoh Corporation] Column: GMPWXL [manufactured by Tosoh Corporation] Column: GMPWXL [manufactured by Tosoh Corporation] The columns are connected in series in the order of 〜, and a sample is introduced from the column side. Detector: Differential refractometer RI-8021 [Tosoh Corporation
Eluent: water / acetonitrile / sodium sulfate = 2,1
00/900/15 (weight ratio) Flow rate; 1.0 ml / min Temperature; 40 ° C. Sample concentration; 0.2% Sample injection volume; 400 μl

Reference Example 1 In a container having an internal volume of 1 L, 197.1 g of water and 40%
207.0 g of an aqueous solution of sodium methyl-1,3-butadiene-1-sulfonate, 161.3 g of an aqueous solution of acrylic acid having a concentration of 80%, 31.7 g of methoxypolyethylene glycol monomethacrylate, 5.0 g of sodium persulfate
And polymerized for 10 hours while stirring at 60 ° C.
A copolymer (salt) was obtained.

Reference Example 2 207.0 g of a 40% sodium 3-allyloxy-2-hydroxypropanesulfonate aqueous solution, 161.3 g of an 80% aqueous acrylic acid solution, 31.7 g of methoxypolyethylene glycol monomethacrylate, sodium persulfate 7 1.5 g dissolved in 100 g of water,
97.1 g was added to a 1-L container with stirring at 70 ° C. over 5 hours. Then 70 ° C
For 2 hours to obtain a copolymer (salt).

Reference Example 3 Instead of using 207.0 g of a 40% aqueous solution of sodium acrylamido-2-methylpropanesulfonate, 207.0 g of a 40% aqueous solution of sodium 3-allyloxy-2-hydroxypropanesulfonate was used. A copolymer (salt) was obtained in the same manner as in Reference Example 2 except that the reaction was carried out.

Reference Example 4 In a container having an internal volume of 1 L, 525.7 g of water and 40% concentration of 2
28.0 g of an aqueous solution of sodium methyl-1,3-butadiene-1-sulfonate, 115.6 g of an aqueous solution of acrylic acid having a concentration of 80%, 36.4 g of methoxypolyethylene glycol monomethacrylate, and 5.0 g of sodium persulfate were charged. Polymerization was carried out for 10 hours while stirring at, to obtain a copolymer (salt).

Reference Example 5 334.9 g of water and 40% concentration of 2
125.4 g of an aqueous solution of sodium methyl-1,3-butadiene-1-sulfonate, 159.2 g of an aqueous solution of acrylic acid having a concentration of 80%, 15.4 g of methoxypolyethylene glycol monomethacrylate, 5.8 g of sodium persulfate
And polymerized for 10 hours with stirring at 70 ° C.
A copolymer (salt) was obtained.

Reference Example 6 207.0 g of a 40% aqueous solution of sodium 3-allyloxy-2-hydroxypropanesulfonate, 161.3 g of an 80% aqueous solution of acrylic acid, and sodium persulfate 1
A solution of 0.0 g in 100 g of water was added to 197.1 water.
g was added to the 1-liter container with stirring at 70 ° C. over 5 hours. After aging at 70 ° C. for 2 hours, 20.0 g of ethylene oxide was reacted,
A copolymer (salt) was obtained.

Polymer A 21.8 g of a 40% aqueous solution of sodium 3-allyloxy-2-hydroxypropanesulfonate, 89.9 g of an 80% aqueous solution of acrylic acid, 28.3 g of methoxypolyethylene glycol monomethacrylate, and sodium persulfate 8. 0 g was dissolved in 100 g of water.
g was added to a 1 L container with stirring at 90 ° C. over 5 hours. Thereafter, aging was performed at 90 ° C. for 2 hours to obtain a copolymer (salt).

Polymer B 103.5 g of a 40% aqueous solution of sodium 2-methyl-1,3-butadiene-1-sulfonate, 80.7 g of an 80% aqueous solution of acrylic acid, 15.8 g of methoxypolyethylene glycol monomethacrylate, A solution of 8.0 g of sodium sulfate dissolved in 100 g of water was added to 310 g of water.
g was sequentially added to a 1-L container with stirring at 90 ° C. over 5 hours. Thereafter, aging was performed at 90 ° C. for 2 hours to obtain a copolymer (salt).

Polymer C In a 1 L container, 197.1 g of water and 40%
207.0 g of an aqueous solution of sodium methyl-1,3-butadiene-1-sulfonate, 161.3 g of an aqueous solution of acrylic acid having a concentration of 80%, and 2.5 g of sodium persulfate were charged.
Polymerization was carried out for 10 hours while stirring at 60 ° C. to obtain a copolymer (salt).

Polymer D In a 1 L container, 228.4 g of water and 2% of 40%
246.1 g of an aqueous solution of sodium methyl-1,3-butadiene-1-sulfonate, 153.9 g of methoxypolyethylene glycol monomethacrylate, and 2.5 g of sodium persulfate were charged, and the mixture was polymerized for 10 hours while stirring at 60 ° C. A polymer (salt) was obtained.

Polymer E: 52.9 g of an 80% strength aqueous solution of acrylic acid, 27.1 g of methoxypolyethylene glycol monomethacrylate,
A solution prepared by dissolving 3.5 g of sodium persulfate in 100 g of water was placed in a 1-liter container charged with 527.9 g of water.
It was added sequentially over 5 hours with stirring at 0 ° C. After that, aging is performed at 90 ° C. for 2 hours to obtain a copolymer (salt).
I got Table 1 shows the compositions and weight average molecular weights (Mw) of the polymers used in Examples and Comparative Examples.

[0044]

[Table 1]

Examples 1 to 6 and Comparative Examples 1 to 6 Using a beaker having an internal volume of 500 ml, a silica concentration of 210
mg / L (in terms of SiO ₂ , adjusted with sodium metasilicate 9-hydrate), magnesium concentration 200 mg / L
(CaCO ₃ equivalent, adjusted by magnesium sulfate heptahydrate), sodium hydrogen carbonate concentration 500 mg / L (Ca
Adjusted to CO ₃ equivalent, adjusted with sodium bicarbonate), copolymer (salt) concentration 100 mg / L, pH 9 (adjusted with sulfuric acid and sodium hydroxide), total volume 500 ml. This solution was charged into a 250 ml polyethylene container capable of being sealed so that no air was mixed therein, and the container was sealed and allowed to stand at 70 ° C. for 140 hours. Then 0.1 μm
The solution was filtered through a filter paper, and the filtrate was analyzed for silica and magnesium concentrations. On the other hand, in order to grasp the effect of suppressing the growth of the precipitated crystal, the average particle size of the precipitate is measured using a laser particle size analysis system; LPA-3000 / 3100 (manufactured by Otsuka Electronics Co., Ltd.).
Was measured. Table 2 shows the results. In the examples, both the precipitation suppressing effect and the crystal growth suppressing effect are superior to the comparative example, and the water-soluble copolymer (salt) which satisfies the limitation of the functional group and the increase in the molecular weight at the same time, that is, the present invention Having a sulfonic acid group, a carboxylic acid group and a polyalkylene oxide group as essential components, and having a weight average molecular weight of more than 50,000 to 300
It can be seen that 10,000 or less water-soluble copolymers (salts) have a synergistically excellent scale prevention effect. In contrast,
Comparative Examples 1 and 2 are examples in which the weight average molecular weight of the water-soluble copolymer (salt) is 50,000 or less, and Comparative Examples 3 to 5 are those in which any of the components (a) to (c) of the present invention is used. Comparative Example 6 was a case where no additive was added, and none of them exhibited the effect of the present invention.

[0046]

[Table 2]

*) Large outside the measurement range.

[0048]

The water-soluble copolymer (salt) containing the sulfonic acid group, carboxylic acid group and polyalkylene oxide group of the present invention as essential components and having a weight average molecular weight of more than 50,000 and not more than 3,000,000 is a scale inhibitor. When it is used, the scale prevention effect, particularly the scale prevention effect for silica scale, is high, and the scale prevention effect can be maintained for a long period of time.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C02F 5/10 620 C02F 5/10 620Z C08F 8/14 C08F 8/14 220/06 220/06 220/28 220/28 220/28 228/02 228/02 236/14 236/14 290/06 290/06 C08G 65/48 C08G 65/48 (72) Inventor Makoto Higami 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan JSR Co., Ltd. In-company (72) Inventor Katsuhiro Ishikawa 2-11-24 Tsukiji, Chuo-ku, Tokyo FSR term in JSR Corporation (reference) 4J005 AA12 BD02 4J027 AC02 AC03 AC04 AC07 AC09 AJ01 AJ02 AJ06 AJ08 BA02 BA03 BA04 BA05 BA06 BA07 BA08 BA13 BA14 BA16 BA19 CB02 CC02 CD08 4J100 AB07R AE18Q AE18R AJ01P AJ02P AJ03P AJ08P AJ09P AK32P AL08Q AL74R AM21R AP01R AP07P AS06R BA02R BA03R BA04Q BA08Q BA09Q BA56H BA56R BB01P FA19 HA31 HA61 HB02 HB14 HB15 HB43 HB52 HC43

Claims (11)

[Claims] 1. (a) a structural unit having a sulfonic acid group,
A water-soluble copolymer (salt) containing (b) a structural unit having a carboxylic acid group and (c) a structural unit having a polyalkylene oxide group as a repeating structural unit, and having a weight average molecular weight of more than 50,000 to 3,000,000 or less. . 2. (a) a monomer having a polymerizable double bond containing a sulfonic acid group, (b) a monomer having a polymerizable double bond containing a carboxylic acid group, and (c) a polyalkylene The water-soluble copolymer (salt) according to claim 1, which is obtained by polymerizing a monomer component containing a monomer having an oxide group and having a polymerizable double bond as a main component. 3. The weight ratio of (a) / (b) / (c) is 2 to 3.
50/40 to 93/5 to 50 [(a) + (b)
+ (C) = 100% by weight], the water-soluble copolymer (salt) according to claim 1 or 2. 4. The weight ratio of (a) / (b) / (c) is 5 to 5.
45/45 to 87/8 to 45 [(a) + (b)
+ (C) = 100% by weight], and the A value represented by the following formula is more than 25 and 3,000,000 or less, the water-soluble copolymer (salt) according to claim 1 or 2. A = [(Mw / 10,000) ⁴ × (% by weight of the structural unit having a polyalkylene oxide group in all the repeating structural units)] / 1,000 (where Mw represents a weight average molecular weight) 5. The water-soluble copolymer (salt) according to claim 1, wherein the degree of polymerization of the polyalkylene oxide constituting (c) is 2 to 50. 6. A scale inhibitor comprising the water-soluble copolymer (salt) according to claim 1 as an active ingredient. 7. The scale inhibitor according to claim 6, wherein the scale is a silica-based scale. 8. A monomer having a polymerizable double bond containing a sulfonic acid group, (b) a monomer having a polymerizable double bond containing a carboxylic acid group, and (c) -1. A monomer component containing a polyalkylene oxide group and having a polymerizable double bond as a main component is polymerized, or a monomer component containing the above components (a) and (b) as main components. During or after the polymerization, by an esterification reaction,
(C) -2 a polyalkylene oxide is introduced or the above-mentioned component (a), component (b) and an active hydrogen-containing monomer [where active hydrogen is contained in component (a) and / or (b)] During or after the polymerization of the monomer component containing (c) -3 alkylene oxide to introduce a polyalkylene oxide group, or to contain a carboxylic acid group. The water-soluble compound according to any one of claims 1 to 5, wherein a sulfonic acid group and a polyalkylene oxide group are introduced after the production of the high molecular weight product, and the weight average molecular weight is increased to more than 50,000 to 3,000,000 or less. A method for producing a copolymer (salt). 9. The weight ratio of component (a) / component (b) / component (c) [component (c) -1, (c) -2 or (c) -3] is 2 to 50/40 to 93. / 5 to 50 [however,
(A) + (b) + (c) = 100% by weight]. The method for producing a water-soluble copolymer (salt) according to claim 8, wherein 10. The weight ratio of component (a) / component (b) / component (c) [component (c) -1, (c) -2 or (c) -3] is 5-45 / 45-87. / 8-45 [however,
(A) + (b) + (c) = 100% by weight], and the A value represented by the following formula is more than 25 and 3,000,000 or less. Salt). A = {(Mw / 10,000) ⁴ × [% by weight of component (c) in components (a) to (c)]} / 1,000 (where Mw represents a weight average molecular weight) 11. The polymerization degree of the polyalkylene oxide is 2
The method for producing a water-soluble copolymer (salt) according to claim 8, wherein