JPS6225164B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel copolymer, its production method, and its uses. To explain in more detail,
A novel product that has two types of blocks with different properties: an anionic block having a carboxyl group and/or a salt thereof in one molecule, and a nonionic and hydrophilic block consisting of an adduct of ethylene oxide and/or propylene oxide. The present invention relates to a copolymer, a method for producing the same, and a pigment dispersant and scale inhibitor made of the new copolymer. BACKGROUND ART Polycarboxylates such as polyacrylates and polymethacucrates have heretofore been usefully used as dispersants and scale inhibitors for certain pigments. However, these polycarboxylates do not exhibit sufficiently satisfactory performance in dispersing special pigments or preventing scale precipitation in circulating water containing a large amount of metal ions. And in order to improve the drawbacks of these polycarboxylates,
Various methods have been attempted, such as copolymerization of (meth)acrylate and hydrophilic hydroxyethyl (meth)acrylate or (meth)acrylamide, or hydrophobic styrene or (meth)acrylic acid ester. At present, none of these methods fully satisfies the required performance. As a result of extensive research in view of the current situation, the present inventors have developed a nonionic block consisting of an adduct of ethylene oxide and/or propylene oxide and an anionic block having a carboxyl group and/or a salt thereof in one molecule. A new copolymer with two types of blocks with different properties, a large and hydrophilic block, can be used as a dispersant for various pigments, a chelating agent, a scale inhibitor, a builder for detergents, a polymeric surfactant, an emulsifier, and an admixture for cement. The present invention was completed based on the discovery that the compound exhibits extremely excellent performance over a wide range of applications such as agents. Therefore, the first object of the present invention is to provide a new copolymer that can be used in these applications and exhibits excellent performance. A second object of the present invention is to provide a method for producing the novel copolymer. Furthermore, the third and fourth objects of the present invention are to provide an excellent pigment dispersant and scale inhibitor comprising the new copolymer. That is, the first invention has the general formula (However, in the formula, m is 0 or a positive integer, n is a positive integer of 1 or more, and m+n=1 to 100, -(
The OC ₂ H ₄ --) unit and the --(OC ₃ H ₆ --) unit may be combined in any order. ) Repeating structural unit (A) shown by and general formula (However, in the formula, R represents hydrogen or a methyl group,
X represents hydrogen, a monovalent metal, a divalent metal, an ammonium group or an organic amine group. ) A new copolymer consisting of a repeating structural unit (B) shown in This relates to a copolymer (hereinafter referred to as a new copolymer). Or, the second invention is the general formula (However, in the formula, m is 0 or a positive integer, n is a positive integer of 1 or more, and m+n=1 to 100, -(
The OC ₂ H ₄ --) unit and the --(OC ₃ H ₆ --) unit may be combined in any order. ) Polyalkylene glycol monoallyl ether (a) represented by and the general formula (However, in the formula, R represents hydrogen or a methyl group,
Z represents hydrogen, an alkali metal or an ammonium group. A novel copolymer () obtained by copolymerizing the (meth)acrylic acid monomer (b) shown in ) using a polymerization initiator and further neutralizing with an alkaline substance if necessary. This relates to a manufacturing method. Moreover, the third invention relates to a pigment dispersant comprising the novel copolymer (). And the fourth
The invention relates to a scale inhibitor comprising a novel copolymer (). In the present invention, the polyalkylene glycol monoallyl ether (a) used to produce the new copolymer (a) is represented by the above general formula, and the number of added moles of ethylene oxide and/or propylene oxide m+n is 1 to 100. When the number of added moles (m+n) is 0, the resulting new copolymer () has low performance such as dispersibility and chelating ability, and on the other hand, when it exceeds 100, the reactivity of such a polyalkylene glycol monoallyl ether copolymer is low. is low. The polyalkylene glycol monoallyl ether (a) used in the present invention is KOH
It can be synthesized by a known method of directly adding ethylene oxide and/or propylene oxide to allyl alcohol using an alkali such as or NaOH as a catalyst. The (meth)acrylic acid monomer (b) is represented by the above general formula, and specific examples include acrylic acid, methacrylic acid, and alkali metal salts and ammonium salts thereof. One or more of these can be used. In the novel copolymer () of the present invention, it is necessary that the total amount of repeating structural units (A) and the total amount of repeating structural units (B) be in a weight ratio of 5:95 to 60:40. . Therefore, when producing a new copolymer, polyalkylene glycol monoallyl ether
The charging ratio of (a) and (meth)acrylic acid monomer (b) is determined by the total amount of repeating structural units (A) and the total amount of repeating structural units (B) in the resulting new copolymer (). must be within the above ratio range. If this ratio is outside of this range, the interaction between the two types of blocks, an anionic block and a nonionic and hydrophilic block contained in one molecule, will not be sufficiently exerted, making it difficult to achieve the objective of the present invention. I can't. Polyalkylene glycol monoallyl ether
In order to produce the new copolymer () from (a) and the (meth)acrylic acid monomer (b), it is sufficient to carry out copolymerization using a polymer initiator. Copolymerization can be carried out by methods such as polymerization in a solvent or bulk polymerization. Polymerization in a solvent can be carried out either batchwise or continuously, and the solvents used in this case include water:
Lower alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; benzene,
Examples include aromatic or aliphatic hydrocarbons such as toluene, xylene, cyclohexane and n-hexane; ethyl acetate; ketone compounds such as acetone and methyl ethyl ketone; From the solubility of the raw material monomers and the resulting new copolymer (2), and the ease of use of the copolymer (2), water and carbon atoms of 1 to 4
It is preferable to use at least one selected from the group consisting of lower alcohols. Carbon number 1-4
Among the lower alcohols, methyl alcohol, ethyl alcohol, and isopropyl alcohol are particularly effective. When polymerization is carried out in an aqueous medium, a water-soluble polymerization initiator such as ammonium or alkali metal persulfate or hydrogen peroxide is used as the polymerization initiator. At this time, an accelerator such as sodium hydrogen sulfite can also be used in combination. In addition, for polymerization using lower alcohols, aromatic hydrocarbons, aliphatic hydrocarbons, ethyl acetate, or ketone compounds as solvents, peroxides such as benzoyl peroxide and lauroyl peroxide; hydroperoxides such as cumene hydroperoxide; Aliphatic azo compounds such as bisisobutyronitrile are used as polymerization initiators. At this time, a promoter such as an amine compound can also be used in combination. Furthermore, when a water-lower alcohol mixed solvent is used, it can be appropriately selected from among the various polymerization initiators or combinations of polymerization initiators and accelerators mentioned above. The polymerization temperature is appropriately determined depending on the solvent and polymerization initiator used, but it is usually carried out within the range of 0 to 120°C. When water is used as a solvent, sodium hydrogen sulfite-oxygen may be used as a polymerization catalyst. In this case, the polymerization is carried out by blowing oxygen gas or a mixed gas of oxygen and an inert gas into the solvent while adding sodium hydrogen sulfite to the solvent containing the raw material monomer.
This can be carried out by proceeding the polymerization reaction within a temperature range of ~80°C. Bulk polymerization is carried out using peroxides such as benzoyl peroxide and lauroyl peroxide; hydroperoxides such as cumene hydroperoxide; and aliphatic azo compounds such as azobisisobutyronitrile as polymerization initiators at 50 to 150°C. carried out within a temperature range. When producing the new copolymer () in this way, the charging ratio of polyalkylene glycol monoallyl ether (a) and (meth)acrylic acid monomer (b), the amount of polymerization initiator used, the polymerization Depending on the temperature, the type and amount of solvent in the case of polymerization in a solvent, etc.
The molecular weight of the resulting copolymer () is 500 to 80,000.
It can be adjusted as appropriate within this range. The novel copolymer () thus obtained can be used as it is for various purposes, but it may be further neutralized with an alkaline substance if necessary. Preferred examples of such alkaline substances include hydroxides, chlorides, and carbonates of monovalent metals and divalent metals, ammonia, and organic amines. The novel copolymer () of the present invention has two types of blocks with different properties in one molecule: an anionic block and a nonionic and hydrophilic block. Due to the interaction, it exhibits excellent performance in a wide range of applications such as dispersants for various pigments, scale inhibitors, chelating agents, detergent builders, polymeric surfactants, emulsifiers, and cement admixtures. In addition, since the terminal of the polyalkylene glycol moiety in the new copolymer () is an OH group, foaming occurs very quickly even when an aqueous solution of the copolymer () is foamed by high-speed stirring. It has special features. Therefore, even when used as a dispersant for inorganic pigments, for example, there is no need to use an antifoaming agent in combination. Furthermore, the polyethylene glycol moiety in the molecule of the new copolymer () is bonded to the main chain of the copolymer () through an ether bond, making it suitable for long-term use at high temperatures, in boiling water, or in high pH ranges. It also has the advantage that no hydrolysis occurs at all, and its performance is not affected in any way. As mentioned above, the novel copolymer () of the present invention exhibits excellent dispersion stability as a pigment dispersant. When using the new copolymer () as a pigment dispersant, pigments that can be effectively dispersed include oxides such as zinc white, titanium oxide, antimony white, red iron oxide, red lead, and chromium oxide; zinc sulfide, cadmium yellow Sulfides such as barium sulfate, gypsum,
Sulfates such as lead sulfate; carbonates such as barium carbonate, calcium carbonate, and lead white; hydroxides such as alumina white and magnesium hydroxide; chromates such as yellow lead, zinc yellow, and barium chromate; various clays. ; satin white; talc; carbon black; and organic pigments such as nitro, azo, and phthalocyanine pigments. Especially Sachin White,
It exhibits a remarkable dispersion stabilizing effect on inorganic pigments such as calcium carbonate, titanium oxide, magnesium hydroxide, and talc. When the new copolymer () is used as a pigment dispersant, the amount added needs to be varied depending on the type of pigment to which it is applied, and it is difficult to specify it unambiguously. 0.005~
It is used appropriately within the range of 5% by weight (in terms of solid content). When using the new copolymer () as a pigment dispersant, its molecular weight can be within a wide range depending on the type of pigment to be applied.
Among them, those in the range of 500 to 50,000 are particularly effective. Further, the novel copolymer (2) of the present invention is used as a scale inhibitor as described above, and exhibits excellent performance in preventing scale precipitation and dispersing precipitated scale. Generally, scale inhibitors are added to water to prevent the formation of calcium, magnesium, barium salts and deposits on the surfaces of pipes, boilers, evaporators, steam ejectors, etc. However, the novel copolymers of the present invention ( ) is used as a scale inhibitor, it acts as a scale precipitation prevention agent and as a dispersant for precipitated scale in any aqueous system where scale formation is a problem. For example, during heating of boiler feed water or process cooling water; during desalination by evaporative desalination of seawater; dust collectors for exhaust gas discharged from blast furnaces, converters, sintering furnaces, etc., and dust and various reaction gases are present. It is highly effective in preventing the precipitation of scale and dispersing the precipitated scale during the circulation of dust collection water used in environmental dust collectors used for environmental purification in workplaces. When using the new copolymer () as a scale inhibitor, the amount added can be varied over a wide range, but it is usually 0.1 to 0.1 to 0.1 to water.
A range of 100ppm (by weight) is recommended.
In addition, in this case, there is no particular restriction on the molecular weight, and a wide range of molecular weights can be used, but among them, 500 to 500
Those in the 50,000 range are particularly effective. When the novel copolymer () of the present invention is used as a scale inhibitor, it is sufficiently effective even when used alone, but if necessary, other scale inhibitors, such as
It can be used in combination with lignin derivatives such as sodium ligninsulfonate, phosphorus compounds such as inorganic polyphosphates, or chelating agents such as EDTA. Further, in desalination of seawater, it may be used in combination with an acid such as sulfuric acid. Furthermore, it is also possible to use it in combination with other water treatment agents known in the art, such as corrosion inhibitors and slime control agents. By using the scale inhibitor of the present invention, the generation of scale can be prevented or suppressed over a long period of time. In addition, even if scale is precipitated due to long-term operation, the precipitated scale is soft due to the action of the scale inhibitor of the present invention, so it can be easily dispersed and removed by water flow. I can do it. Examples will be described in more detail below, but it goes without saying that the present invention is not limited only to these examples. In addition, unless otherwise specified, parts in the examples refer to parts by weight, and % refers to % by weight. All viscosities in the examples were measured using a Bismethron viscometer manufactured by Seiki Kogyo Kenkyusho at 25°C.
Measurement was performed at 60 rpm. Furthermore, the molecular weight was measured using gel permation chromatography (Model 244, manufactured by Waters). Example 1 Polyalkylene glycol monoallyl ether (on average 8 ethylene oxide units and 2 propylene oxide units per molecule) was placed in a glass reaction vessel equipped with a thermometer, stirrer, dropping funnel, gas inlet tube and reflux condenser. (including) 40 copies and water 443
The inside of the reaction vessel was replaced with nitrogen while stirring,
Heated to 95°C under nitrogen atmosphere. Thereafter, 421 parts of a 38% sodium acrylate aqueous solution and 80 parts of a 5% ammonium persulfate aqueous solution were each added over 120 minutes. After the addition was complete, an additional 16 parts of 5% ammonium persulfate aqueous solution was added over 20 minutes. After completing the addition of the monomer aqueous solution, the temperature was maintained at 95° C. for 120 minutes to complete the polymerization reaction, and a new copolymer (1) was obtained. A 40% aqueous solution of this copolymer (1) had a pH of 7.6 and a viscosity of 382 cps. Further, the molecular weight of this copolymer (1) was 4,200. Example 2 Into the same reaction vessel as in Example 1, 60 parts of polyalkylene glycol monoallyl ether (containing on average 25 ethylene oxide units and 5 propylene oxide units per molecule) and 452 parts of water were charged, and the mixture was stirred. The inside of the reaction vessel was purged with nitrogen and heated to 95°C in a nitrogen atmosphere. Thereafter, 368 parts of a 38% aqueous sodium methacrylate solution and 100 parts of a 5% aqueous ammonium persulfate solution were each added over 120 minutes. After the addition was complete, an additional 20 parts of 5% ammonium persulfate aqueous solution was added over 20 minutes. After completing the addition of the monomer aqueous solution, the temperature was maintained at 95° C. for 120 minutes to complete the polymerization reaction, and a new copolymer (2) was obtained. This copolymer (2)
The pH of a 40% aqueous solution of was 7.5 and the viscosity was 2100 cps. Moreover, the molecular weight of this copolymer (2) was 19,000. Example 3 238 parts of water was charged into the same reaction vessel as in Example 1,
The inside of the reaction vessel was purged with nitrogen while stirring, and heated to 95°C in a nitrogen atmosphere. Then 10% polyalkylene glycol monoallyl ether (average of 4% polyalkylene glycol monoallyl ether per molecule)
514 parts of a 35% ammonium acrylate aqueous solution and 40 parts of a 5% ammonium persulfate aqueous solution were each added over 120 minutes. After the addition was complete, 8 parts of 5% ammonium persulfate aqueous solution was added over 20 minutes. After the addition of the monomer aqueous solution was completed, the temperature was maintained at 95° C. for 120 minutes to complete the polymerization reaction, and a new copolymer (3) was obtained. The pH of a 40% aqueous solution of this copolymer (3) is 6.5, and the viscosity is 460 cps.
It was hot. Further, the molecular weight of this copolymer (3) was 6,700. Example 4 In the same reaction vessel as in Example 1, polyalkylene glycol monoallyl ether (30
56 parts of ethylene oxide units and 10 propylene oxide units) and 517 parts of water were charged, the inside of the reaction vessel was purged with nitrogen while stirring, and the mixture was heated to the boiling point in a nitrogen atmosphere. Thereafter, 379 parts of a 38% aqueous solution of partially neutralized sodium acrylate (75 mol% neutralization) and 40 parts of a 5% ammonium persulfate aqueous solution were each added over 120 minutes. Thereafter, the temperature was maintained at the boiling point for 120 minutes to complete the polymerization reaction, and a new copolymer (4) was obtained. A 40% aqueous solution of this copolymer (4)
The pH was 6.4 and the viscosity was 1004 cps. Further, the molecular weight of this copolymer (4) was 5,900. Example 5 In the same reaction vessel as in Example 1, 96 parts of polyalkylene glycol monoallyl ether (containing on average 4 ethylene oxide units and 4 propylene oxide units per molecule) and isopropyl alcohol (hereinafter abbreviated as IPA) were added. 279 parts of an azeotropic composition of water and water (IPA/water = 87.4/12.6 (weight ratio)) were charged, the inside of the reaction vessel was purged with nitrogen while stirring, and heated to the boiling point in a nitrogen atmosphere. Then acrylic acid
204 parts, 3 parts of benzoyl peroxide and IPA-
A mixture of 306 parts of water azeotrope was added over 120 minutes.
After the addition was completed, 0.6 parts of benzoyl peroxide dispersed in 11.4 parts of the IPA-water azeotropic composition was further added in two portions every 30 minutes. After the addition of the monomer mixture was completed, the temperature was maintained at the boiling point for 120 minutes to complete the polymerization reaction. Thereafter, it was neutralized with 283 parts of a 40% caustic soda aqueous solution. Next, IPA was distilled off to obtain a new copolymer (5). This copolymer (5)
The 45% aqueous solution had a pH of 8.5 and a viscosity of 580 cps.
Moreover, the molecular weight of this copolymer (5) was 3,900. Example 6 In the same reaction vessel as in Example 1, 49 parts of polypropylene glycol monoallyl ether (containing an average of 4 propylene oxide units per molecule) and 531 parts of isopropyl alcohol (hereinafter abbreviated as IPA) were added.
The inside of the reaction vessel was purged with nitrogen while stirring, and heated to the boiling point in a nitrogen atmosphere. after that,
A mixture of 151 parts of acrylic acid, 2 parts of benzoyl peroxide and 227 parts of IPA was added over 120 minutes. After the addition was completed, 0.4 parts of benzoyl peroxide dispersed in 39.6 parts of IPA was further added in two portions every 30 minutes. After completing the addition of the monomer mixture,
The temperature was maintained at boiling point for 120 minutes to complete the polymerization reaction. Thereafter, it was neutralized with 210 parts of a 40% caustic soda aqueous solution. Next, IPA was distilled off to form a new copolymer.
The PH of the 45% aqueous solution of this copolymer (6) from which (6) was obtained is
8.6, and the viscosity was 482 cps. Also, this copolymer
The molecular weight of (6) was 3000. Example 7 Polypropylene glycol monoallyl ether (on average 20
40 parts (containing propylene oxide units),
120 parts of acrylic acid and 0.8 parts of azobisisobutyronitrile were each charged, and the inside of the reaction vessel was sufficiently purged with nitrogen while stirring. Thereafter, it was gradually heated and copolymerized to obtain a solid new copolymer (7). A 20% aqueous solution obtained by completely neutralizing this copolymer (7) with a caustic soda aqueous solution has a pH of 9.0 and a viscosity of
It was 733cps. Moreover, the molecular weight of this copolymer (7) was 72,000. Example 8 Cyclohexane 536 was placed in the same reaction vessel as in Example 1.
The inside of the reaction vessel was replaced with nitrogen while stirring.
Heated to boiling point under nitrogen atmosphere. Then polyalkylene glycol monoallyl ether (average 1
A monomer solution of 16 parts (containing 2 ethylene oxide units and 8 propylene oxide units in the molecule) dissolved in 144 parts of cyclohexane.
20% of 64 parts of acrylic acid, and 20% of a solution of 4 parts of decanoyl peroxide in 36 parts of cyclohexane were added to perform initial polymerization. Then the rest of each of the above
80% of each was added in 120 minutes. After addition,
The temperature was further maintained at the boiling point for 120 minutes to complete the polymerization reaction, and the mixture was cooled and filtered to obtain a powder of the new copolymer (8). The pH of a 30% aqueous solution obtained by completely neutralizing this copolymer (8) powder with a caustic soda aqueous solution was 9.1.
The viscosity was 992 cps. Moreover, the molecular weight of this copolymer (8) was 31,000. Example 9 580 parts of ethyl acetate was charged into the same reaction vessel as in Example 1, and the interior of the reaction vessel was replaced with nitrogen while stirring, and heated to the boiling point in a nitrogen atmosphere. Next, 80 parts of polyalkylene glycol monoallyl ether (containing on average 5 ethylene oxide units and 15 propylene oxide units per molecule) was added to ethyl acetate.
20% of a monomer solution dissolved in 120 parts, 20% of 120 parts of acrylic acid, and 20% of a solution of 2.0 parts of benzoyl peroxide dissolved in 98 parts of ethyl acetate were added, and initial polymerization was carried out. I did this. Thereafter, the remaining 80% of each of the above was added over a period of 120 minutes. After the addition was completed, the temperature was maintained at the boiling point for an additional 120 minutes to complete the polymerization reaction. After the polymerization was completed, neutralization was carried out using 167 parts of a 40% caustic soda aqueous solution to obtain a new copolymer (9), and then ethyl acetate was distilled off. A 20% aqueous solution of this copolymer (9) had a pH of 8.8 and a viscosity of 220 cps. Moreover, the molecular weight of this copolymer (9) was 51,000. Example 10 In the same reaction vessel as Example 1, 315.6 parts of water was charged,
The temperature was 25°C. 160 ml of air per minute was blown into this water through a glass sintered porous tube with micropores of about 10 microns, and polyalkylene glycol monoallyl ether (12 ethylene oxide units and 3 propylene oxide units per molecule on average) was mixed with stirring. A monomer mixture aqueous solution consisting of 30 parts (containing units) and 567 parts of a 30% sodium acrylate aqueous solution.
and 87. parts of a 10% aqueous sodium bisulfite solution were added over 120 minutes each. As the polymerization started, the injected microbubbles became even finer. During the polymerization reaction, the heat generated by the polymerization was cooled with cold water, and the reaction temperature was maintained at 24-26°C. After the addition of the monomer mixture aqueous solution and the sodium bisulfite aqueous solution was completed, air was continued to be blown for an additional 30 minutes to complete the polymerization reaction, and a new copolymer (10) was obtained. 40 of this copolymer (10)
% aqueous solution had a pH of 9.0 and a viscosity of 560 cps.
Moreover, the molecular weight of this copolymer (10) was 4,500. Example 11 Copolymers (1), (6) and
(10), and sodium polyacrylate (commercial product,
The dispersing ability for Sachin White (manufactured by Shiraishi Kogyo Co., Ltd.) was evaluated according to the following procedure using a compound (molecular weight: 5000) as a dispersant. That is, an aqueous solution of deionized water, Sachin White, and the amount of dispersant shown in Table 1 was placed in a stainless steel beaker with an internal volume of 1, and heated for 20 minutes in a Lab Disper (manufactured by Tokushu Kika Kogyo Co., Ltd., Model MR-L). Stirring was performed to prepare 25% satin white slurry, and the viscosity of each slurry was measured.
The results were as shown in Table 1. As shown in Table 1, the dispersant of the present invention has excellent dispersion ability even when added in a small amount compared to the low molecular weight sodium polyacrylate (molecular weight 5000) conventionally used in this field. There is.

[Table] Example 12 Copolymers (1) obtained in Examples 1, 4, 5 and 10,
(4), (5) and (10), and sodium polyacrylate (commercial product, molecular weight 5000) were used as a dispersant to obtain calcium carbonate (average particle size 0.2 μm, Shiraishi Kogyo Co., Ltd.).
The dispersion ability and dispersion stability for the following products were evaluated according to the following procedure. That is, a solid content of 4.2 g (1.0 parts per 100 parts of calcium carbonate) of the dispersant aqueous solution was placed in a stainless steel beaker with an internal volume of 700 ml, and water was added to obtain 280 g of the dispersant aqueous solution. The aqueous dispersant solution was uniform and transparent. This dispersant aqueous solution was added to Lab Disper (manufactured by Tokushu Kika Kogyo Co., Ltd., MR-
420 g of calcium carbonate fine powder (manufactured by Shiraishi Kogyo Co., Ltd.) was added over about 20 minutes while stirring with a L-shape.
After the addition is complete, stir for another 30 minutes to reach a solid concentration of 60%.
An aqueous dispersion of calcium carbonate was obtained. The viscosity of this aqueous dispersion and the viscosity after standing overnight were as shown in Table 2. As shown in Table 2, by using the dispersant of the present invention, an aqueous calcium carbonate dispersion can be obtained with good dispersibility, and the obtained aqueous dispersion has low viscosity and excellent stability.

[Table] Example 13 Copolymers obtained in Examples 1, 4, 5, 6 and 10
(1), (4), (5), (6) and (10) and sodium polyacrylate (commercial product, molecular weight 5000) were used as scale inhibitors to test their ability to prevent scale against calcium carbonate according to the following procedure. I evaluated it. i.e. 750 ml of deionized water in a beaker, 0.58% of calcium chloride
50ml of an aqueous solution, 50ml of an aqueous solution containing 200ppm of the above scale inhibitor, and 0.44ml of sodium bicarbonate.
% aqueous solution under stirring, then adjust the pH to 8.5 with a 0.01N aqueous sodium hydroxide solution, and then add deionized water to make a total volume of 1000 g to prepare a 5 times supersaturated aqueous solution of calcium carbonate at 25°C. did. This 5-times supersaturated aqueous solution was divided into four equal parts, each placed in a glass bottle, sealed tightly and allowed to stand at 60°C. After 5 hours, 10 hours, 20 hours, and 40 hours, the test solution was taken out and cooled to 25°C. The test solution was filtered through Toyo Paper quantitative paper No. 5C, and 0.01 mol of EDTA aqueous solution was added to the test solution. The concentration of calcium ions remaining in the sample was measured, and the amount of precipitated calcium carbonate was calculated. The results are shown in Table 3. or,
Similarly, the amount of precipitated calcium carbonate was also investigated in the case where no scale inhibitor was used.

[Table] As is clear from the results shown in Table 3, the novel copolymer () of the present invention has an excellent scale prevention effect as a scale inhibitor. Example 14 In the circulating water system for blast furnace exhaust gas dust collection water, a test short pipe (3/8 inch diameter, 150 mm length) was installed in the middle of circulating the thickner treated water to the dust collector, and Example 5
The copolymer (5) obtained in step 1 was added to the circulating water at a concentration of 0.5 ppm at the thickener outlet, and the scale was operated continuously for 30 days to determine the weight of scale adhering to the test short tube and its adhesion rate. It was measured. The test conditions were as follows. The results are shown in Table 4. Water temperature: 35-40℃ Flow rate: 1.5m/sec PH: 7-8 (no particular adjustment) Similarly, when commercially available sodium polyacrylate (molecular weight 5000) is added instead of copolymer (5) The amount of scale adhesion and the adhesion rate were measured for the case where no scale inhibitor was added, and the results are shown in Table 4. However, when no scale inhibitor was added, the continuous operation period was 15 days.

[Table] As is clear from the results shown in Table 4, the novel copolymer (2) of the present invention has an excellent effect as a scale inhibitor in preventing scale precipitation in collected dust water during continuous operation. Example 15 Put 700ml of seawater into the beaker 1, add the copolymer (1) obtained in Example 1 to 5.0ppm, and add a pipe heater (100V, 500W) as a heat source to this seawater. The solution was immersed and evaporated while stirring. 5.0ppm of copolymer (1) with evaporation concentration
The added seawater was sequentially replenished. While performing such operations, the amount of scale attached to the pipe heater was determined at the time when the concentration ratio increased to 4 times. The results are shown in Table 5. Similarly, when copolymers (5) and (10) obtained in Examples 5 and 10 and commercially available sodium polyacrylate (molecular weight 5000) were added instead of copolymer (1), the scale The amount of scale attached to the pipe heater was determined in the case where no inhibitor was added, and the results are shown in Table 5.

[Table] As is clear from the results shown in Table 5, the new copolymer () of the present invention has an excellent effect as a scale inhibitor in preventing scale precipitation in seawater desalination equipment by evaporative desalination. There is.

Claims (1)

[Claims] 1. General formula (However, in the formula, m is 0 or a positive integer, n is a positive integer of 1 or more, and m+n=1 to 100, -(
The OC ₂ H ₄ --) unit and the --(OC ₃ H ₆ --) unit may be combined in any order. ) Repeating structural unit (A) shown by and general formula (However, in the formula, R represents hydrogen or a methyl group,
X represents hydrogen, a monovalent metal, a divalent metal, an ammonium group or an organic amine group. ), the total amount of (A) and the total amount of (B) are in the weight ratio of 5:95 to 60:40, and the molecular weight is within the range of 500 to 80,000. Polymer. 2 General formula (However, in the formula, m is 0 or a positive integer, n is a positive integer of 1 or more, and m+n=1 to 100, -(
The OC ₂ H ₄ --) unit and the --(OC ₃ H ₆ --) unit may be combined in any order. ) Polyalkylene glycol monoallyl ether (a) represented by and the general formula (However, in the formula, R represents hydrogen or a methyl group,
Z represents hydrogen, an alkali metal or an ammonium group. ) A general formula obtained by copolymerizing the (meth)acrylic acid monomer (b) represented by (b) using a polymerization initiator and further neutralizing with an alkaline substance if necessary (However, in the formula, m is 0 or a positive integer, n is a positive integer of 1 or more, and m+n=1 to 100, -(
The OC ₂ H ₄ --) unit and the --(OC ₃ H ₆ --) unit may be combined in any order. ) Repeating structural unit (A) and general formula shown by (However, in the formula, R represents hydrogen or a methyl group,
X represents hydrogen, a monovalent metal, a divalent metal, an ammonium group or an organic amine group. ), the total amount of (A) and the total amount of (B) are in the weight ratio of 5:95 to 60:40, and the molecular weight is within the range of 500 to 80,000. Method for producing polymers. 3. A method for producing a novel copolymer according to claim 2, wherein the copolymerization is carried out in a solvent. 4. The method for producing a novel copolymer according to claim 3, wherein at least one selected from the group consisting of water and a lower alcohol having 1 to 4 carbon atoms is used as a solvent. 5. The method for producing a novel copolymer according to claim 4, which uses water as a solvent and sodium bisulfite-oxygen as a polymerization initiator. 6. The method for producing a novel copolymer according to claim 3, using at least one selected from the group consisting of aromatic hydrocarbons and aliphatic hydrocarbons as a solvent. 7. The method for producing a novel copolymer according to claim 3, wherein at least one selected from the group consisting of ethyl acetate and ketone compounds is used as a solvent. 8 Claim 2 in which copolymerization is carried out by bulk polymerization
Method for producing the novel copolymer described in Section 1. 9 General formula (However, in the formula, m is 0 or a positive integer, n is a positive integer of 1 or more, and m+n=1 to 100, -(
The OC ₂ H ₄ --) unit and the --(OC ₃ H ₆ --) unit may be combined in any order. ) Repeating structural unit (A) shown by and general formula (However, in the formula, R represents hydrogen or a methyl group,
X represents hydrogen, a monovalent metal, a divalent metal, an ammonium group or an organic amine group. ), the total amount of (A) and the total amount of (B) are in the weight ratio of 5:95 to 60:40, and the molecular weight is within the range of 500 to 80,000. Pigment dispersant made of polymer. 10 General formula (However, in the formula, m is 0 or a positive integer, n is a positive integer of 1 or more, and m+n=1 to 100, -(
The OC ₂ H ₄ --) unit and the --(OC ₃ H ₆ --) unit may be combined in any order. ) Repeating structural unit (A) shown by and general formula (However, in the formula, R represents hydrogen or a methyl group,
X represents hydrogen, a monovalent metal, a divalent metal, an ammonium group or an organic amine group. ), the total amount of (A) and the total amount of (B) are in the weight ratio of 5:95 to 60:40, and the molecular weight is within the range of 500 to 80,000. A scale inhibitor made of polymer.