SULFURIC-ACID-(SALT)-ESTER-GROUP-CONTAINING COPOLYMER AND METHOD FOR PRODUCING SAME

Abstract

The invention aims to provide a polymer that can exhibit excellent calcium phosphate scale inhibition performance. The invention relates to a sulfuric acid (salt) ester group-containing copolymer containing a structural unit (a) derived from a sulfuric acid (salt) ester group-containing monomer (A) represented by the formula (1) and a structural unit (b) derived from an unsaturated carboxylic acid monomer (B).

##STR00001##

Claims

1. A sulfuric acid ester group and/or sulfuric acid ester salt group-containing copolymer comprising: a structural unit (a) derived from a sulfuric acid ester group or sulfuric acid ester salt group-containing monomer (A); and a structural unit (b) derived from an unsaturated carboxylic acid monomer (B), the sulfuric acid ester group or sulfuric acid ester salt group-containing monomer (A) being represented by the formula (1): ##STR00004## wherein AO is an oxyalkylene group, m is a number of 2 to 5, n is an average number of moles of oxyalkylene group added and a number of 1 to 300, and M is a cation.

2. The sulfuric acid ester group and/or sulfuric acid ester salt group-containing copolymer according to claim 1, wherein m in the formula (1) is 2.

3. The sulfuric acid ester group and/or sulfuric acid ester salt group-containing copolymer according to claim 1, wherein n in the formula (1) is a number of 2 to 50.

4. The sulfuric acid ester group and/or sulfuric acid ester salt group-containing copolymer according to claim 1, wherein a proportion of the structural unit (a) is 1 to 20 mol % in 100 mol % of all structural units of the copolymer.

5. The sulfuric acid ester group and/or sulfuric acid ester salt group-containing copolymer according to claim 1, wherein the copolymer is used for a water treatment agent.

6. The sulfuric acid ester group and/or sulfuric acid ester salt group-containing copolymer according to claim 1, wherein the copolymer is used for a detergent.

7. A water treatment agent comprising the sulfuric acid ester group and/or sulfuric acid ester salt group-containing copolymer according to claim 1.

8. A detergent composition comprising the sulfuric acid ester group and/or sulfuric acid ester salt group-containing copolymer according to claim 1.

9. A sulfuric acid ester group and/or sulfuric acid ester salt group-containing copolymer composition comprising: the sulfuric acid ester group and/or sulfuric acid ester salt group-containing copolymer according to claim 1; and a sulfuric acid ester group or sulfuric acid ester salt group-containing monomer (A) and/or an unsaturated carboxylic acid monomer (B), an amount of the sulfuric acid ester group or sulfuric acid ester salt group-containing monomer (A) being 1.5 mass % or less relative to 100 mass % of the sulfuric acid ester group and/or sulfuric acid ester salt group-containing copolymer, an amount of the unsaturated carboxylic acid monomer (B) being 2 mass % or less relative to 100 mass % of the sulfuric acid ester group and/or sulfuric acid ester salt group-containing copolymer.

10. The sulfuric acid ester group and/or sulfuric acid ester salt group-containing copolymer composition according to claim 9, wherein an amount of sulfamic acid in the sulfuric acid ester group and/or sulfuric acid ester salt group-containing copolymer composition is 10 mass % or less relative to 100 mass % of the sulfuric acid ester group and/or sulfuric acid ester salt group-containing copolymer.

Description

DESCRIPTION OF EMBODIMENTS

[0118] Hereinafter, the invention will be described in detail with reference to examples. However, the invention should not be limited to these examples. Unless otherwise mentioned, the term part(s) means part(s) by weight and % means % by mass.

<Measurement Conditions of Weight Average Molecular Weight (GPC)>

[0119] Apparatus: HLC-8320 GPC, Tosoh Corporation [0120] Detector: RI [0121] Column: SHODEX Asahipak GF-310-HQ, GF-710-HQ, GF-1G 7B, Showa Denko K.K.

[0122] Column temperature: 40 C. [0123] Flow rate: 0.5 mL/min [0124] Calibration curve: polyacrylic acid standard, Sowa Kagaku Co., Ltd. [0125] Eluent: 0.1 N aqueous sodium acetate solution

<Measurement of Non-Volatile Matter Content>

[0126] The polymer (composition) was allowed to stand in an oven heated to 120 C. for two hours and thus dried. The non-volatile matter content (mass %) and the volatile matter content (mass %) were calculated from the difference between the polymer weights before and after drying.

<Amount of Remaining Monomer>

[0127] The monomers and other components were quantified by liquid chromatography under the following conditions unless otherwise stated. [0128] Measurement apparatus: 8020 series, Tosoh Corporation Column: CAPCELL PAK Cl UG120 (three pieces), Shiseido Company, Limited [0129] Temperature: 40.0 C. [0130] Eluent: 10 mmol/L aqueous disodium hydrogen phosphate dodecahydrate solution (pH was controlled to 7 with phosphoric acid)/acetonitrile=45/55 (volume ratio) Flow rate: 1.0 ml/min [0131] Detector: RI [0132] Measurement apparatus: e-2695, Waters Corporation [0133] Detector: UV detector (200 nm) [0134] Column: SHODEX RSpak DE-413L, Showa Denko K.K. [0135] Temperature: 40.0 C. [0136] Eluent: 0.1% aqueous phosphoric acid solution [0137] Flow rate: 1.0 ml/min

[0138] Table 1 shows the results.

<Calcium Phosphate Scale Prevention (Inhibition) Performance (%)>

[0139] In a 225-ml screw top bottle were placed deionized water, a boric acid/sodium borate pH buffer solution, an aqueous calcium chloride solution, each of the polymer aqueous solutions prepared in the examples and the comparative examples, and an aqueous sodium phosphate solution in the stated order to prepare 100 ml of a test solution having a pH of 8.6, a polymer concentration of 6 mg/L or 7 mg/L in terms of non-volatile matter content, a calcium hardness of 200 mg CaCO.sub.3/L, and a phosphate ion of 10 mg PO.sub.4.sup.3/L. The bottle was sealed and allowed to stand at 60 C. for 24 hours. The test solution was filtered through a filter paper having a pore size of 0.1 m, and the concentration of residual phosphoric acid ions in the filtrate was analyzed. Separately, the same test solution but not containing the polymer was prepared as a blank test solution. The blank test solution was treated in the same manner as for the polymer-containing test solution, and the concentration of residual phosphoric acid ions was analyzed. The calcium phosphate scale prevention rate was determined by the following formula. Table 1 shows the results.

Calcium phosphate scale prevention rate(%)=100(RQ)/(PQ) [0140] P: Concentration of phosphoric acid ions charged (mg/L) [0141] Q: Concentration of residual phosphoric acid ions in the blank (mg/L) [0142] R: Concentration of residual phosphoric acid ions (mg/L)

<Measurement of Chelating Ability (Ability to Capture Calcium Ions)>

[0143] In a 100-mL beaker was placed 50 g of a 0.001 mol/L aqueous calcium chloride solution, and then 10 mg of a copolymer in solid content was added thereto. Subsequently, the pH of the aqueous solution was controlled to 9 to 11 with dilute sodium hydroxide. Thereafter, 1 ml of a 4 mol/L aqueous potassium chloride solution was added thereto as a stabilizer for a calcium ion electrode under stirring.

[0144] The amount of free calcium ions was measured with an ion analyzer (model EA920, Orion Corporation) and a calcium ion electrode (model 93-20, Orion Corporation), and the number of milligrams of calcium ions chelated, in terms of calcium carbonate, per gram of the copolymer (i.e., calcium ion-capturing ability which was a kind of chelating ability) was calculated. The ability to capture calcium ions was expressed in mg CaCO.sub.3/g.

<Carbon Black Dispersing Ability>

[0145] First, ion exchange water was added to 67.56 g of glycine, 52.6 g of sodium chloride, and 60 mL of a 1 mol/L aqueous sodium chloride solution to prepare 600 g of a glycine buffer solution.

[0146] Then, pure water was added to 0.3268 g of calcium chloride dihydrate and 60 g of the glycine buffer solution to prepare 1000 g of a dispersion.

[0147] Next, 0.03 g of carbon black was placed in a test tube (test tube with rim and guide line, 30 mL, 18 mm diameter180 mm height, Maruemu Corporation), followed by addition of 27 g of the dispersion and 3 g of a 0.1% by weight aqueous solution of a test sample (polymer composition) (in terms of solid content) to the test tube.

[0148] Then, the test tube was sealed and shaken to uniformly disperse the carbon black. The test tube was allowed to stand for one week, and then the state of the contents in the test tube was evaluated using the following criteria by visual observation with a patterned paper placed behind the test tube. Table 2 shows the results.

<Evaluation Criteria>

[0149] Good: The dispersion was black in color.

[0150] Fair: The dispersion was light gray in color, and the pattern was seen through the dispersion.

[0151] Poor: The dispersion was transparent.

[0152] A darker-colored dispersion through which the pattern was harder to see was deemed to have better carbon black dispersing ability.

<Clay Dispersing Ability>

[0153] First, ion exchange water was added to 67.56 g of glycine, 52.6 g of sodium chloride, and 60 ml of a 1 mol/l aqueous NaOH solution to prepare 600 g of a glycine buffer solution.

[0154] Then, pure water was added to 0.3268 g of calcium chloride dihydrate and 60 g of the glycine buffer solution to prepare 1000 g of a dispersion.

[0155] Separately, a 0.1% aqueous polymer solution in terms of solid content was prepared. Then, a test tube having a volume of about 30 cc commonly used in experiments was charged with 0.3 g of a clay of JIS test powder 1-Class 8 (KANTO loam, fine particles. The Association of Powder Process Industry and Engineering, JAPAN), 27 g of the dispersion, and 3 g of the 0.1% aqueous polymer solution to prepare a test solution.

[0156] The test solution had a calcium concentration of 200 ppm in terms of calcium carbonate.

[0157] The test tube was sealed with parafilm and gently shaken to disperse the clay throughout the solution, followed by shaking up and down 20 times.

[0158] The test tube was allowed to stand at a place away from direct sunlight for 20 hours, and 5 ml of the supernatant was removed from the test solution with a volumetric pipette.

[0159] The supernatant liquid was placed in a cell having an optical path length of 1 cm and subjected to absorbance (ABS) measurement using a UV spectroscope (UV-1800, SHIMADZU) at a wavelength of 380 nm. The resulting value indicates clay dispersing ability in high hardness water. Table 2 shows the results.

<Miscibility>

[0160] (1) A mixture of 1 g of polyoxyethylene alkyl ether (C12-C14 secondary alcohol with 9 mol of ethylene oxide added there to on average) and 1 g of an aqueous polymer composition solution (30 mass % or 5 mass %) was allowed to stand at room temperature for one hour.

[0161] (2) A case without turbidity was evaluated as good, and a case with turbidity or separation was evaluated as poor. The case without turbidity indicates that the detergent containing the polymer composition can be in a uniform state for a long period of time. Table 2 shows the results.

SYNTHESIS EXAMPLE 1

Sulfuric Acid (Salt) Ester Group-Containing Monomer (1)

[0162] An isoprenol ethylene oxide 10 mol adduct (hereinafter, also referred to as IPN10) was sulfated with a sulfating agent by a usual method (Hiroshi Horiguchi, 1975, New Surfactants (Shin-Kaimen Kasseizai), Mitsui Shuppan Co., Ltd., pp. 322-326 and Ryohei Oda and Kazuhiro Sachimura, 1965, Synthesis of Surfactants I (Kaimen Ksseizai Gousei-hen I), Maki Shoten, pp. 105-110), and was diluted with water to prepare a 80% aqueous monomer solution as a monomer composition (1).

SYNTHESIS EXAMPLE 2

Monomer Composition (2) for Comparative Examples: IPES10

[0163] A 5-L four-necked flask equipped with a stirring blade, a thermometer, and a condenser was charged with 1737 g of an isoprenol ethylene oxide adduct having an average number of moles of ethylene oxide of 10 mol (hereinafter, also referred to as IPN10, hydroxyl value: 106.5 (mg KOH/g)), 1692 g of epichlorohydrin, and 411 g of 48% NaOH.

[0164] The contents were reacted for six hours by stirring while the temperature was maintained at 50 C. After the reaction, the salt generated was removed to obtain an organic layer. The epichlorohydrin and water were removed from the organic layer to obtain 1779 g of a reaction solution containing an intermediate (A) (a compound represented by the formula (1) having a structure in which the average value of n is 10, R.sup.1 is a CH.sub.2CH.sub.2 group, R.sup.2 is a CH.sub.2CH.sub.2 group, and R.sup.3 is a CH.sub.3 group). The results of analysis by liquid chromatography showed that the reaction solution contained 1467 g of the intermediate (A) and 108 g of IPN10. Next, a 5-L four-necked flask equipped with a stirring blade, a thermometer, a condenser, and a dropping funnel was charged with the reaction solution in an amount such that the amount of the intermediate (A) was 1247 g, and the solution was heated under stirring so that the internal temperature was 50 C. To the reaction solution were slowly added dropwise over one hour a liquid mixture of 90.4 g of 48% NaOH, 1796.8 g of pure water, 269.9 g of 64% sodium bisulfite (hereinafter, also referred to as SBS) in terms of SO.sub.2, and 4H-TEMPO in an amount of 2500 ppm relative to the sodium bisulfite while the internal temperature was maintained at 50 C. The reaction solution was additionally stirred for four hours. Thus, 3671 g of a solution of a monomer composition (2) containing a monomer (2) (hereinafter, referred to as IPES) as a major constituent was obtained.

EXAMPLE 1

Copolymer 1

[0165] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 170.9 g of pure water and 1.8 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 87 C. under stirring. Then, under stirring, 122.1 g of a 80% aqueous solution of acrylic acid (hereinafter, also referred to as 80% AA), 6.0 g of 48% sodium hydroxide (hereinafter, also referred to as 48% NaOH), 127.1 g of the 80% monomer composition (1), 52.6 g of a 15% aqueous solution of sodium persulfate (hereinafter, also referred to as 15% NaPS), and 19.4 g of 35% SBS were added dropwise to the flask through different nozzles. The dropwise additions of the solutions were started simultaneously. The addition times of the solutions were as follows: the 80% AA and the 48% NaOH were each added over 180 min, the 80% monomer composition (1) was added over 160 min, the 15% NaPS was added over 210 min, and the 35% SBS was added over 170 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 15% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes to complete the polymerization. Thus, an aqueous solution of a copolymer (1) was obtained. The copolymer (1) had a weight average molecular weight of 9000.

EXAMPLE 2

Copolymer 2

[0166] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 99.5 g of pure water and 1.4 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 87 C. under stirring. Then, under stirring, 92.9 g of 80% AA, 49.6 g of a 40% aqueous solution of sodium 3-allyloxy-2-hydroxy-l-propanesulfonate (hereinafter, also referred to as 40% HAPS), 76.8 g of the 80% monomer composition (1), 64.8 g of 15% NaPS, and 14.9 g of 35% SBS were added dropwise to the flask through different nozzles.

[0167] The dropwise additions of the solutions were started simultaneously. The addition times of the solutions were as follows: the 80% AA was added over 180 min, the 40% HAPS was added over a total of 120 min, where a 16.5-g portion was added over the initial 30 min and a 33.1-g portion was added over the last 90 min, the 80% monomer composition (1) was added over 170 min, the 15% NaPS was added over a total of 200 min, where a 24.3-g portion was added over the initial 120 min and a 40.5-g portion was added over the last 80 min, and the 35% SBS was added over 170 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 15% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes to complete the polymerization. Thus, an aqueous solution of a copolymer (2) was obtained. The copolymer (2) had a weight average molecular weight of 9500.

EXAMPLE 3

Copolymer 3

[0168] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 142.1 g of pure water and 1.8 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to the boiling point under stirring. Then, under stirring, 150.7 g of 80% AA, 7.0 g of 48% NaOH, 155.4 g of a 75% aqueous monomer solution as the monomer composition (1), 25.9 g of 15% NaPS, and 17.3 g of a 45% aqueous solution of sodium hypophosphite (hereinafter, also referred to as 45% SHP) were added dropwise to the flask through different nozzles. The dropwise additions of the solutions were started simultaneously. The addition times of the solutions were as follows: the 80% AA and the 48% NaOH were each added over 180 min, the 75% monomer composition (1) was added over 170 min, the 15% NaPS was added over a total of 210 min, where a 19.4-g portion was added over the initial 180 min and a 6.5-g portion was added over the last 30 min, and the 45% SHP was added over 180 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 15% NaPS solution, the polymerization reaction solution was maintained (aged) at the boiling point for another 30 minutes to complete the polymerization. Thus, an aqueous solution of a copolymer (3) was obtained. The copolymer (3) had a weight average molecular weight of 9500.

EXAMPLE 4

Copolymer 4

[0169] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 142.1 g of pure water and 1.8 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 87 C. under stirring. Then, under stirring, 150.7 g of 80% AA, 7.0 g of 48% NaOH, 155.4 g of the 75% monomer composition (1), 25.9 g of 15% NaPS, and 17.3 g of 45% SHP were added dropwise to the flask through different nozzles. The dropwise additions of the solutions were started simultaneously. The addition times of the solutions were as follows: the 80% AA and the 48% NaOH were each added over 180 min, the 75% monomer composition (1) was added over 170 min, the 15% NaPS was added over a total of 210 min, where a 19.4-g portion was added over the initial 180 min and a 6.5-g portion was added over the last 30 min, and the 45% SHP was added over 180 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 15% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes to complete the polymerization. Thus, an aqueous solution of a copolymer (4) was obtained. The copolymer (4) had a weight average molecular weight of 10500.

EXAMPLE 5

Copolymer 5

[0170] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 105.4 g of pure water and 1.8 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 87 C. under stirring. Then, under stirring, 147.1 g of 80% AA, 7.2 g of 48% NaOH, 151.7 g of the 75% monomer composition (1), 63.4 g of 15% NaPS, and 23.4 g of 35% SBS were added dropwise to the flask through different nozzles. The dropwise additions of the solutions were started simultaneously. The addition times of the solutions were as follows: the 80% AA and the 48% NaOH were each added over 180 min, the 80% monomer composition (1) was added over 170 min, the 15% NaPS was added over 210 min, and the 35% SBS was added over 170 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 15% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes to complete the polymerization. Thus, an aqueous solution of a copolymer (5) was obtained. The copolymer (5) had a weight average molecular weight of 10500.

EXAMPLE 6

Copolymer 6

[0171] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 138.0 g of pure water and 1.8 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 87 C. under stirring. Then, under stirring, 169.4 g of 80% AA, 8.3 g of 48% NaOH, 136.7 g of the 75% monomer composition (1), 27.2 g of 15% NaPS, and 18.5 g of 35% SBS were added dropwise to the flask through different nozzles. The dropwise additions of the solutions were started simultaneously. The addition times of the solutions were as follows: the 80% AA and the 48% NaOH were each added over 180 min, the 75% monomer composition (1) was added over 170 min, the 15% NaPS was added over 210 min, and the 35% SBS was added over 170 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 15% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes to complete the polymerization. Thus, an aqueous solution of a copolymer (6) was obtained. The copolymer (6) had a weight average molecular weight of 22000.

Example 7

Copolymer 7

[0172] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 136.3 g of pure water and 1.8 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 87 C. under stirring. Then, under stirring, 165.6 g of 80% AA, 7.7 g of 48% NaOH, 124.6 g of the 80% monomer composition (1), 27.9 g of 15% NaPS, and 35.4 g of 35% SBS were added dropwise to the flask through different nozzles. The dropwise additions of the solutions were started simultaneously. The addition times of the solutions were as follows: the 80% AA and the 48% NaOH were each added over 180 min, the 80% monomer composition (1) was added over 170 min, the 15% NaPS was added over a total of 210 min, where a 20.9-g portion was added over the initial 180 min and a 7.0-g portion was added over the last 30 min, and the 35% SBS was added over 170 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 15% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes to complete the polymerization. Thus, an aqueous solution of a copolymer (7) was obtained. The copolymer (7) had a weight average molecular weight of 16500.

Example 8

Copolymer 8

[0173] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 117.0 g of pure water and 1.8 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 87 C. under stirring. Then, under stirring, 186.2 g of 80% AA, 8.6 g of 48% NaOH, 103.0 g of the 80% monomer composition (1), 61.4 g of 15% NaPS, and 22.0 g of 35% SBS were added dropwise to the flask through different nozzles.

[0174] The dropwise additions of the solutions were started simultaneously. The addition times of the solutions were as follows: the 80% AA and the 48% NaOH were each added over 180 min, the 80% monomer composition (1) was added over 175 min, the 15% NaPS was added over 210 min, and the 35% SBS was added over 170 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 15% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes to complete the polymerization. Thus, an aqueous solution of a copolymer (8) was obtained. The copolymer (8) had a weight average molecular weight of 12500.

EXAMPLE 9

Copolymer 9

[0175] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 173.2 g of pure water and 1.8 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 87 C. under stirring. Then, under stirring, 128.6 g of 80% AA, 6.0 g of 48% NaOH, 95.6 g of the 80% monomer composition (1), 19.1 g of an isoprenol ethylene oxide 10 mol adduct (hereinafter, IPN10), 55.3 .sub.g of 15% NaPS, and 20.4 g of 35% SBS were added dropwise to the flask through different nozzles. The dropwise additions of the solutions were started simultaneously. The addition times of the solutions were as follows: the 80% AA and the 48% NaOH were each added over 180 min, the 80% monomer composition (1) and IPN10 were each added over 175 min, the 15% NaPS was added over 210 min, and the 35% SBS was added over 170 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 15% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes to complete the polymerization. Thus, an aqueous solution of a copolymer (9) was obtained. The copolymer (9) had a weight average molecular weight of 8000.

COMPARATIVE EXAMPLE 1

Comparative Copolymer 1

[0176] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 299.6 g of pure water and 2.8 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 87 C. under stirring. Then, under stirring, 217.3 g of 80% AA, 10.1 g of 48% NaOH, 141.4 g of IPN10, 85.8 g of 15% NaPS, and 40.8 g of 35% SBS were added dropwise to the flask through different nozzles. The dropwise additions of the solutions were started simultaneously. The addition times of the solutions were as follows: the 80% AA and the 48% NaOH were each added over 180 min, the IPN10 was added over 150 min, the 15% NaPS was added over a total of 200 min, where a 41.1-g portion was added over the initial 130 min and a 44.7-g portion was added over the last 70 min, and the 35% SBS was added over 170 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 15% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes to complete the polymerization. Thus, an aqueous solution of a comparative copolymer (1) was obtained. The comparative copolymer (1) had a weight average molecular weight of 9000.

COMPARATIVE EXAMPLE 2

Comparative Copolymer 2

[0177] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 150.8 g of pure water and 1.8 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 87 C. under stirring. Then, under stirring, 89.5 g of 80% AA, 90.4 g of 40% HAPS, 87.3 g of IPN10, 61.9 g of 15% NaPS, and 18.4 g of 35% SBS were added dropwise to the flask through different nozzles. The dropwise additions of the solutions were started simultaneously. The addition times of the solutions were as follows: the 80% AA was added over 180 min, the 40% HAPS was added over 40 min, the IPN10 was added over 170 min, the 15% NaPS was added over a total of 200 min, where a 29.2-g portion was added over the initial 130 min and a 32.7-g portion was added over the last 70 min, and the 35% SBS was added over 170 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 15% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes to complete the polymerization. Thus, an aqueous solution of a comparative copolymer (2) was obtained. The comparative copolymer (2) had a weight average molecular weight of 11000.

COMPARATIVE EXAMPLE 3

Comparative Copolymer 3

[0178] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 51.2 of pure water and 1.8 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 87 C. under stirring. Then, under stirring, 70.7 g of 80% AA, 304.5 g of the monomer composition (2), 51.1 g of 15% NaPS, and 20.6 g of 35% SBS were added dropwise to the flask through different nozzles. The dropwise additions of the solutions were started simultaneously. The addition times of the solutions were as follows: the 80% AA was added over 180 min, the monomer composition (2) was added over 170 min, the 15% NaPS was added over a total of 200 min, where a 19.2-g portion was added over the initial 120 min and a 31.9-g portion was added over the last 80 min, and the 35% SBS was added over 170 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 15% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes to complete the polymerization. Thus, an aqueous solution of a comparative polymer (3) was obtained. The comparative polymer (3) had a weight average molecular weight of 11000.

COMPARATIVE EXAMPLE 4

Comparative Copolymer 4

[0179] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 53.0 g of pure water and 2.1 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 87 C. under stirring. Then, under stirring, 85.3 g of 80% AA, 86.1 g of 40% HAPS, 278.9 g of the monomer composition (2), 67.4 g of 15% NaPS, and 27.2 g of 35% SBS were added dropwise to the flask through different nozzles.

[0180] The dropwise additions of the solutions were started simultaneously. The addition times of the solutions were as follows: the 80% AA was added over 180 min, the 40% HAPS was added over 30 min, the monomer composition (2) was added over 170 min, the 15% NaPS was added over a total of 200 min, where a 25.3-g portion was added over the initial 120 min and a 42.1-g portion was added over the last 80 min, and the 35% SBS was added over 170 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 15% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes to complete the polymerization. Thus, an aqueous solution of comparative polymer (4) was obtained. The comparative polymer (4) had a weight average molecular weight of 13000.

COMPARATIVE EXAMPLE 5

Comparative Copolymer 5>

[0181] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 103.3 g of pure water and 1.8 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 87 C. under stirring. Then, under stirring, 186.0 g of 80% AA, 247.2 g of 40% HAPS, 67.2 g of 15% NaPS, 28.8 g of 35% SBS, and 1.8 g of 35% hydrogen peroxide (hereinafter, referred to as HP) were added dropwise to the flask through different nozzles. The dropwise additions of the solutions other than HP were started simultaneously. The dropwise addition of HP was started 185 min after the start of addition of the other materials. The addition times of the solutions were as follows: the 80% AA was added over 180 min, the 40% HAPS was added over a total of 140 min, where a 61.8-g portion was added over the initial 20 min and a 185.4 portion was added over the last 120 min, the 15% NaPS was added over a total of 200 min, where a 31.9-g portion was added over the initial 130 min and a 35.3-g portion was added over the last 70 min, the 35% SBS was added over 170 min, and the HP was added over 5 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 15% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes to complete the polymerization. Thus, an aqueous solution of a comparative polymer (5) was obtained. The comparative polymer (5) had a weight average molecular weight of 10500.

COMPARATIVE EXAMPLE 6

Comparative Copolymer 6

[0182] A 2.5-L stainless steel separable flask equipped with a thermometer, a stirrer, and a reflux condenser was charged with 149.8 g of pure water and 1.2 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 85 C. under stirring. Then, under stirring, 385.1 g of 80% AA, 17.8 g of 48% NaOH, 51.8 g of 15% NaPS, and 63.6 g of 35% SBS were added dropwise to the flask through different nozzles. The dropwise additions of the solutions were started simultaneously. The addition times of the solutions were as follows: the 80% AA was added over 180 min, the 15% NaPS was added over 185 min, and the 5% SBS was added over 175 min. After the dropwise addition of the 15% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes and neutralized by addition of 330.7 g of 48% NaOH. Thus, an aqueous solution of a comparative polymer (6) was obtained. The comparative polymer (6) had a weight average molecular weight of 7000.

COMPARATIVE EXAMPLE 7

Comparative Copolymer 7

[0183] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 72.4 g of pure water and 2.1 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 87 C. under stirring. Then, under stirring, 131.2 g of 80% AA, 340.4 g of 40% HAPS, 24.3 g of 30% NaPS, 28.2 g of 35% SBS, and 1.5 of 35% hydrogen peroxide (hereinafter, referred to as HP) were added dropwise to the flask through different nozzles. The dropwise additions of the solutions other than HP were started simultaneously. The dropwise addition of HP was started 185 min after the start of addition of the other materials. The addition times of the solutions were as follows: the 80% AA was added over 180 min, the 40% HAPS was added over a total of 120 min, where a 170.2-g portion was added over the initial 30 min and a 170.2 portion was added over the last 90 min, the 30% NaPS was added over a total of 200 min, where a 14.6-g portion was added over the initial 130 min and a 9.7-g portion was added over the last 70 min, the 35% SBS was added over 170 min, and the HP was added over 5 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 30% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes to complete the polymerization. Thus, an aqueous solution of a comparative polymer (7) was obtained. The comparative polymer (7) had a weight average molecular weight of 9000.

COMPARATIVE EXAMPLE 8

Comparative Copolymer 8

[0184] A 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle impellers) was charged with 73.9 g of pure water and 2.1 g of a 0.6% aqueous solution of Mohr's salt, and the contents were heated to 87 C. under stirring. Then, under stirring, 141.6 g of 80% AA, 422.2 g of 40% HAPS, 27.4 g of 30% NaPS, 31.8 g of 35% SBS, and 1.7 g of 35% hydrogen peroxide (hereinafter, referred to as HP) were added dropwise to the flask through different nozzles. The dropwise additions of the solutions other than HP were started simultaneously. The dropwise addition of HP was started 185 min after the start of addition of the other materials. The addition times of the solutions were as follows: the 80% AA was added over 180 min, the 40% HAPS was added over a total of 60 min, where a 211.1-g portion was added over the initial 20 min and a 211.1-g portion was added over the last 40 min, the 30% NaPS was added over a total of 200 min, where a 16.4-g portion was added over the initial 130 min and a 11.0-g portion was added over the last 70 min, the 35% SBS was added over 170 min, and the HP was added over 5 min. Each of the solutions was continuously added dropwise at a constant rate. After the dropwise addition of the 30% NaPS solution, the polymerization reaction solution was maintained (aged) at 87 C. for another 30 minutes to complete the polymerization. Thus, an aqueous solution of a comparative polymer (8) was obtained. The comparative polymer (8) had a weight average molecular weight of 10000.

TABLE-US-00001 TABLE 1 Ca phosphate scale Initiator Ca prevention performance (%) Monomer composition and chain Amount of residual monomer (ppm) capturing Copolymer Copolymer ratio (mol %) transfer agent Mw AA Monomer (1) HAPS IPN ability 6 mg/L 7 mg/L Example 1 AA/Monomer (1) = NaPS/SBS/Fe 9000 930 200 140 74 89 89.3/10.7 Example 2 AA/HAPS/Monomer 9500 730 0 3000 150 56 86 (1) = 84.5/7.4/8.1 Example 3 AA/Monomer (1) = NaPS/SHP 9500 40 450 90 >95 90/10 Example 4 AA/Monomer (1) = 10500 6 1200 91 >95 90/10 Example 5 AA/Monomer (1) = NaPS/SBS/Fe 10500 2600 5500 58 90/10 Example 6 AA/Monomer (1) = 92/8 22000 5400 650 23 64 Example 7 AA/Monomer (1) = 92/8 16500 1600 6250 30 63 Example 8 AA/Monomer (1) = 94/6 12500 550 0 Example 9 AA/Monomer (1)/IPN = 8000 2000 1100 0 48 80 90/7.7/2.3 Comparative AA/IPN10 = 90.0/10.0 NaPS/SBS/Fe 9000 4200 1600 170 37 56 Example 1 Comparative AA/HAPS/IPN10 = 11000 0 7500 0 90 <15 19 Example 2 75/12.5/12.5 Comparative AA/IPES = 82/18 11000 2100 60 80 93 Example 3 Comparative AA/HAPS/IPES = 13000 200 5800 60 50 86 Example 4 85/12.5/12.5 Comparative AA/HAPS = 82/18 10500 6 4300 200 15 37 Example 5 Comparative Polyacrylic acid 7000 10 250 <15 <15 Example 6 Comparative AA/HAPS = 70/30 9000 0 23000 37 62 Example 7 Comparative AA/HAPS = 67/33 10000 0 26000 22 55 Example 8

TABLE-US-00002 TABLE 2 Initiator Carbon black Clay Monomer composition and chain dispersing dispersing Miscibility Miscibility ratio (mol %) transfer agent Mw ability ability (1) (2) Example 1 AA/Monomer (1) = NaPS/SBS/Fe 9000 Good 0.913 Good 89.3/10.7 Example 2 AA/HAPS/Monomer 9500 Good 0.781 Good (1) = 84.5/7.4/8.1 Example 3 AA/Monomer (1) = NaPS/SHP 9500 Good Good Good 90/10 Example 4 AA/Monomer (1) = 10500 Good Good Good 90/10 Example 5 AA/Monomer (1) = NaPS/SBS/Fe 10500 Good Good 90/10 Example 6 AA/Monomer (1) = 92/8 22000 Good Good Example 7 AA/Monomer (1) = 92/8 16500 Good Good Example 8 AA/Monomer (1) = 94/6 12500 Good Good Example 9 AA/Monomer (1)/IPN = 8000 Good Good 90/7.7/2.3 Comparative AA/IPN10 = 90.0/10.0 NaPS/SBS/Fe 9000 Good 0.913 Example 1 Comparative AA/HAPS/IPN10 = 11000 Good 1.056 Poor Example 2 75/12.5/12.5 Comparative AA/IPES = 82/18 11000 Good 1.285 Poor Example 3 Comparative AA/HAPS/IPES = 13000 Good 1.572 Example 4 85/12.5/12.5 Comparative AA/HAPS = 82/18 10500 Fair 0.873 Poor Good Example 5 Comparative Polyacrylic acid 7000 Poor 0.782 Poor Poor Example 6 Comparative AA/HAPS = 70/30 9000 Poor Example 7 Comparative AA/HAPS = 67/33 10000 Poor Example 8 Miscibility (1) Polyoxyethylene alkyl ether (1 g) + 30% aqueous polymer solution (1 g) Miscibility (2) Polyoxyethylene alkyl ether (1 g) + 5% aqueous polymer solution (1 g)