Carboxyl-group-containing copolymer, and method for producing same

Abstract

The present invention provides a carboxyl group-containing copolymer having a better calcium ion trapping ability and a better carbon black dispersing ability than any conventional carboxyl group-containing copolymers. The present invention relates to a carboxyl group-containing copolymer including a structural unit (a) derived from an unsaturated monocarboxylic acid monomer (A), a structural unit (b) derived from an unsaturated dicarboxylic acid monomer (B), and a structural unit (c) derived from a cationic monomer (C).

Claims

1. A carboxyl group-containing copolymer comprising: a structural unit (a) derived from an unsaturated monocarboxylic acid monomer (A), a structural unit (b) derived from an unsaturated dicarboxylic acid monomer (B), and a structural unit (c) derived from a cationic monomer (C), wherein the carboxyl group-containing copolymer optionally contains at least one selected from the group consisting of a structural unit (d) derived from a sulfonic acid group-containing monomer (D), and a structural unit (e) derived from a monomer (E) other than the unsaturated monocarboxylic acid monomer (A), the unsaturated dicarboxylic acid monomer (B), the cationic monomer (C), and the sulfonic acid group-containing monomer (D), a proportion of the structural unit (b) in 100 mol % of all structural units is 10 to 70 mol %, a proportion of the structural unit (e) in 100 mol % of all structural units is 0 to 20 mol %, wherein the cationic monomer (C) contains a group represented by any of the following formulas (1) to (3): ##STR00006## wherein in the formulas (1) and (2), R.sup.1 and R.sup.2 are the same as or different from each other and each represents a hydrogen atom or a C1-C20 hydrocarbon group optionally containing a functional group, at least one of R.sup.1 or R.sup.2 being a C1-C20 hydrocarbon group optionally containing a functional group, in the formula (3), R.sup.3 to R.sup.5 are the same as or different from each other and each represent a C1-C20 hydrocarbon group optionally containing a functional group, and W.sup.− is an anion.

2. The carboxyl group-containing copolymer according to claim 1, further comprising the structural unit (d) derived from a sulfonic acid group-containing monomer (D).

3. The carboxyl group-containing copolymer according to claim 1, wherein the cationic monomer (C) contains a hydrophobic group.

4. The carboxyl group-containing copolymer according to claim 1, wherein the unsaturated monocarboxylic acid monomer (A) includes at least one selected from the group consisting of (meth)acrylic acid and salts of (meth)acrylic acid.

5. The carboxyl group-containing copolymer according to claim 1, wherein the unsaturated dicarboxylic acid monomer (B) includes at least one selected from the group consisting of maleic acid, salts of maleic acid, and maleic anhydride.

6. The carboxyl group-containing copolymer according to claim 1, wherein the carboxyl group-containing copolymer has a weight average molecular weight of 2000 to 500000.

7. A scale inhibitor comprising the carboxyl group-containing copolymer according to claim 1.

8. A method for producing a carboxyl group-containing copolymer, the method comprising polymerizing a monomer component that contains an unsaturated dicarboxylic acid monomer (B) and a hydrophobic group-containing cationic monomer (C1), wherein the monomer component optionally contains at least one selected from the group consisting of an unsaturated monocarboxylic acid monomer (A), a sulfonic acid group-containing monomer (D), and a monomer (E) other than the unsaturated monocarboxylic acid monomer (A), the unsaturated dicarboxylic acid monomer (B), the hydrophobic group-containing cationic monomer (C1), and the sulfonic acid group-containing monomer (D), a proportion of the unsaturated dicarboxylic acid monomer (B) in 100 mol % of all monomers of the monomer component is 10 to 70 mol %, a proportion of the monomer (E) in 100 mol % of all monomers is 0 to 20 mol %, wherein polymerization is conducted at a pH of 0 to 6 for at least 30% of a time, taking, from a start of the polymerization reaction to an end of a last completed addition of addition of a monomer component, addition of a chain transfer agent, and addition of a polymerization initiator, as 100%, wherein the hydrophobic group-containing cationic monomer (C1) contains a group represented by any of the following formulas (6) to (8): ##STR00007## wherein in the formulas (6) and (7), R.sup.11 and R.sup.12 are the same as or different from each other and each represents a hydrogen atom or a C1-C20 hydrocarbon group optionally containing a functional group, at least one of R.sup.11 or R.sup.12 is a C1-C20 hydrocarbon group containing no functional group or containing a hydrophobic functional group, and a total carbon number of the hydrocarbon groups R.sup.11 and R.sup.12 is 4 or more, in the formula (8), R.sup.13 to R.sup.15 are the same as or different from each other and each represent a C1-C20 hydrocarbon group optionally containing a functional group, at least one of R.sup.13 to R.sup.15 being a C1-C20 hydrocarbon group containing no functional group or containing a hydrophobic functional group, and in the formulas (7) and (8), W.sup.− is an anion.

9. The method for producing a carboxyl group-containing copolymer according to claim 8, wherein the unsaturated dicarboxylic acid monomer (B) includes at least one selected from the group consisting of maleic acid, salts of maleic acid, and maleic anhydride.

10. The method for producing a carboxyl group-containing copolymer according to claim 8, wherein the monomer component contains an unsaturated monocarboxylic acid monomer (A).

11. The method for producing a carboxyl group-containing copolymer according to claim 8, wherein the polymerization is conducted at 70° C. to 120° C.

12. The method for producing a carboxyl group-containing copolymer according to claim 8, wherein the carboxyl group-containing copolymer has a weight average molecular weight of 2000 to 500000.

13. The method for producing a carboxyl group-containing copolymer according to claim 8, wherein an amount of the chain transfer agent is 1 to 20 g relative to 1 mol total of the monomer component.

14. The method for producing a carboxyl group-containing copolymer according to claim 8, wherein a number of carbon atoms of the hydrocarbon group in R.sup.11-R.sup.15 is from 2 to 20 each.

15. The method for producing a carboxyl group-containing copolymer according to claim 8, wherein the cationic monomer (C1) is represented by the formula (9).

16. The method for producing a carboxyl group-containing copolymer according to claim 8, wherein R.sup.11 and R.sup.12 are the same as or different from each other and each represents a C1-C20 hydrocarbon group optionally containing a functional group.

17. The method for producing a carboxyl group-containing copolymer according to claim 8, wherein the upper limit of pH in the polymerizing is 5.8.

Description

DESCRIPTION OF EMBODIMENTS

(1) The present invention is described in further detail below with reference to examples, but the present invention is not limited to these examples. It should be noted that the terms “part(s)” and “%” refer to “part(s) by weight” and “mass %”, respectively, unless otherwise stated.

(2) The following parameters were determined or quantified by the methods described later.

(3) (1) Weight average molecular weight (Mw)

(4) (2) Ca trapping ability

(5) (3) Carbon black dispersing ability

(6) (4) Anti-redeposition properties

(7) (5) Beef tallow dispersing ability

(8) (1) Measurement of Weight Average Molecular Weight (Mw)

(9) Apparatus: high performance GPC apparatus (HLC-8320GPC) produced by Tosoh Corporation

(10) Detector: RI

(11) Column: SHODEX Asahipak GF-310-HQ, GF-710-HQ, GF-1G 7B produced by Showa Denko K.K.

(12) Column temperature: 40° C.

(13) Flow rate: 0.5 ml/min

(14) Calibration curve: POLYACRYLIC ACID STANDARD produced by Sowa Kagaku Co., Ltd.

(15) Eluent: 0.1 N sodium acetate/acetonitrile=3/1 (mass ratio)

(16) (2) Measurement of Ca Trapping Ability

(17) First, 50 g of a 0.01 mol/L, 0.001 mol/L, or 0.0001 mol/L aqueous solution was prepared as a calcium ion standard solution for a calibration curve using calcium chloride dehydrate. The pH of the aqueous solution was adjusted to 9 to 11 with a 48% aqueous solution of NaOH. Then, 1 mL of a 4 mol/L aqueous solution of potassium chloride (hereinafter, abbreviated as 4M-KCl aqueous solution) was added to the aqueous solution, and the contents were sufficiently stirred with a magnetic stirrer. Thereby, a sample solution for a calibration curve was prepared. Separately, a needed amount (50 g per sample) of a 0.001 mol/L aqueous solution was prepared as a calcium ion standard test solution using calcium chloride dehydrate. Then, 10 mg (in terms of solids) of a test sample (polymer) was weighed in a 100 cc beaker, and 50 g of the calcium ion standard test solution was added thereto. The contents were sufficiently stirred with a magnetic stirrer. The pH of the solution was adjusted to 9 to 11 with a 48% aqueous solution of NaOH, and 1 mL of a 4M-KCl aqueous solution was added thereto. Thereby, a test sample solution was prepared similarly to the sample solution for a calibration curve. The thus-prepared sample solution for a calibration curve and the test sample solution were subjected to measurement using a titrator COMTITE-550 produced by Hiranuma Sangyo Co., Ltd. with a calcium ion electrode 93-20 and a reference electrode 90-01 produced by Orion Corp. The amount of calcium ions trapped by the sample (polymer) was determined from the values obtained from the measurement for the sample solutions for calibration curve and the test sample solution. The resulting value was converted to the amount trapped by 1 g of the solids of the polymer. The amount was expressed as the number of milligrams in terms of calcium carbonate (mgCaCO.sub.3/g). The resulting value is defined as the calcium ion trapping ability.

(18) (3) Measurement of Carbon Black Dispersing Ability

(19) A buffer solution and a 0.1% aqueous polymer solution were prepared. The buffer solution was prepared in the following way: pure water was added to 6.76 g of glycine, 5.26 g of sodium chloride, and 0.50 g of 48% sodium hydroxide to prepare 60.0 g of a solution in total; and to the solution were added 0.123 g of calcium chloride dihydrate, 0.056 g of magnesium chloride hexahydrate, and pure water to prepare 1000.0 g of the buffer solution. The 0.1% aqueous polymer solution was prepared by diluting one of the polymers obtained in Examples 1 to 8 and Comparative Examples 1 to 7 with an appropriate amount of water to a solids concentration of 0.1% by mass.

(20) Next, the solutions and carbon black powder were put into a 30-mL test tube in the following order and amounts. First, 0.03 g of carbon black powder was added, then 27.0 g of the buffer solution was added, and finally 3.0 g of the 0.1% aqueous polymer solution was added.

(21) After the addition of the solutions and the carbon black powder in the stated order, the test tube was sealed and slowly inverted 60 times so that the contents were stirred. Thereafter, the test tube was allowed to stand at room temperature for 20 hours. Immediately after 20 hours, the supernatant was put into a 1-cm quartz cell, and the absorbance at a UV wavelength of 380 nm thereof was measured using a spectrophotometer (measurement apparatus: UV-1800 produced by Shimadzu Corporation). The resulting value is defined as the carbon black dispersing ability. A higher absorbance indicates a better dispersion of the carbon black powder.

(22) (4) Measurement of Anti-Redeposition Properties

(23) The reflectances as whiteness of white cotton fabrics and white cotton/polyester blend fabrics used as samples were previously measured. The reflectance may be measured using a colorimetric difference meter ND-1001DP produced by Nippon Denshoku Industries Co., Ltd., for example. Pure water was added to 1.47 g of calcium chloride dihydrate to prepare 10 kg of hard water. Pure water was added to 4.0 g of sodium linear alkylbenzenesulfonate (LAS) to prepare 100 g of a 4% aqueous surfactant solution. A tergotmeter was set at 25° C., and 1000 mL of the hard water and 5.0 g of an aqueous polymer solution (concentration 1.0%) were put into a pot. The contents were stirred for one minute. Thereafter, 5.0 g of the 4% aqueous surfactant solution and 0.5 g of clay (JIS test powder 1 Class 11) were put into the pot. The contents were stirred at 100 rpm for one minute. Then, 5.0 g of the white fabric was put in the pot and stirred at 100 rpm for 10 minutes. The white fabric was wrung by hand, and put in a pot with 1 L of the hard water. The contents were stirred at 100 rpm for two minutes. The white fabric was again wrung by hand and dried with an iron while wrinkles were smoothed with a filler cloth placed therebetween. The reflectance as whiteness of the fabric was measured again using the colorimetric difference meter. The anti-soil redeposition properties were determined from the following equation, based on the measurement results. Anti-redeposition properties (%)=(Whiteness of fabric after washing)/(Whiteness of original white fabric)×100

(24) (5) Measurement of Beef Tallow Dispersing Ability

(25) First, pure water was added to 0.123 g of calcium chloride dihydrate and 0.056 g of magnesium chloride hexahydrate to prepare 1000.0 g of hard water. Separately, pure water was added to 83.3 g of 25% sodium polyoxyethylene lauryl ether sulfate and 11.9 g of 35% lauryl dimethylamine oxide up to 100.0 g and the mixture was stirred to prepare a 25% aqueous surfactant solution having a ratio of sodium polyoxyethylene lauryl ether sulfate:lauryl dimethylamine oxide=5:1. Then, the hard water was added to an aqueous polymer solution having a solid content of 2 mg and 0.20 g of the 25% aqueous surfactant solution prepared as described above to prepare 20 g of a composition for cleaning.

(26) A 50-mL glass screw tube was charged with 0.10 g of beef tallow and 20 g of the composition for cleaning prepared as described above, and the contents were stirred and then allowed to stand at 25° C. for six hours. Immediately after six hours, the supernatant was put into a 1 cm quartz cell, and the absorbance at a UV wavelength of 380 nm thereof was measured using a spectrophotometer. The resulting value is defined as the beef tallow dispersing ability. A higher absorbance indicates a better beef tallow dispersing ability.

Example 1

Synthesis of Monomer

(27) The following describes a method for synthesizing a dibutylamine derivative monomer of allyl glycidyl ether (AGE) (AGE-DBA).

(28) A 2000 mL four-necked glass flask equipped with a reflux condenser and a stirrer (paddle blades) was charged with 319.9 g of pure water and 387.0 g of dibutylamine, and the contents were heated to 60° C. under stirring. Then, 359.5 g of AGE was added over 60 minutes, and the contents were reacted for five hours. The resulting monomer was washed with pure water and saturated saline, and the water layer was removed with a separatory funnel. Water in the organic layer was sufficiently removed with sodium sulfate, and the sodium sulfate was removed by filtration. Thus, 100% AGE-DBA was obtained.

Synthesis of Polymer

(29) A 500-mL glass separable flask equipped with a reflux condenser and a stirrer was charged with 27.7 g of pure water and 29.4 g (0.30 mol) of maleic anhydride, and the contents were heated to 90° C. under stirring. After the heating, 14.0 g (0.17 mol) of 48% sodium hydroxide (hereinafter, abbreviated as 48% NaOH) and 6.6 mg of Mohr's salt were added thereto. After the addition, the solution had a pH of 0.4. Subsequently, 75.7 g (0.84 mol) of a 80% aqueous solution of acrylic acid (hereinafter, abbreviated as 80% AA), 17.1 g (0.06 mol) of an addition reaction product of allyl glycidyl ether (AGE) with dibutylamine (hereinafter, abbreviated as AGE-DBA), 48.0 g (6.0 g per mole of the monomers added (here, the monomers added refer to all the monomers added, and the same shall apply to the following examples and comparative examples)) of a 15% aqueous solution of sodium persulfate (hereinafter, abbreviated as 15% NaPS), and 29.5 g (8.0 g per mole of the monomers added) of a 32.5% aqueous solution of sodium bisulfite (hereinafter, abbreviated as 32.5% SBS) were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA and AGE-DBA were each added over 120 minutes, 15% NaPS was added over 150 minutes, and 32.5% SBS was added over 110 minutes. During the addition, each component was continuously added dropwise at a constant rate. After the dropwise addition, the reaction solution was further maintained at 90° C. and aged for 60 minutes to complete the polymerization. The reaction solution immediately after the completion of the polymerization had a pH of 2.0. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 46.0 g (i.e., 0.55 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (1) having a solids concentration of 46 mass % and a final degree of neutralization of 52 mol % was obtained. The reaction ratio of AGE-DBA was 98%. The polymer (1) had a Mw of 9500, a Ca trapping ability of 294, and a carbon black dispersing ability of 0.77.

Example 2

(30) A 2.5 L stainless steel separable flask equipped with a reflux condenser and a stirrer was charged with 110.0 g of pure water and 216.2 g (2.205 mol) of maleic anhydride, and the contents were heated to 100° C. under stirring. After the heating, 155.0 g (1.86 mol) of 48% NaOH, 133.5 g (0.245 mol) of a 40% aqueous solution of sodium 3-allyloxy-2-hydroxypropanesulfonate (hereinafter, abbreviated as 40% HAPS), and 59.63 g (0.245 mol) of AGE-DBA were added thereto. After the addition, the solution had a pH of 4.8. Subsequently, 198.6 g (2.205 mol) of 80% AA, 183.8 g (2.205 mol) of 48% NaOH, 98.0 g (3.0 g per mole of the monomers added) of 15% NaPS, 33.6 g (2.4 g per mole of the monomers added) of a 35% aqueous solution of hydrogen peroxide (hereinafter, abbreviated as 35% H.sub.2O.sub.2), and 173.9 g of pure water were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA, 48% NaOH, and pure water were each added over 120 minutes, 15% NaPS was added over 150 minutes, and 35% H.sub.2O.sub.2 was added over 90 minutes. During the addition, each component was continuously added dropwise at a constant rate. The reaction solution had a pH of 5.2, 5.4, 5.7, 5.9, and 6.0 respectively after 30, 60, 90, 120, and 150 minutes from the start of dropwise addition.

(31) After the dropwise addition, the reaction solution was further maintained at 100° C. and aged for 35 minutes to complete the polymerization. The reaction solution immediately after the completion of the polymerization had a pH of 6.0. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 57.4 g (i.e., 0.69 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (2) having a solids concentration of 49 mass % and a final degree of neutralization of 78 mol % was obtained. The reaction ratio of AGE-DBA was 92%. The polymer (2) had a Mw of 10200, a Ca trapping ability of 363, and a carbon black dispersing ability of 0.58.

Example 3

(32) A 500-mL glass separable flask equipped with a reflux condenser and a stirrer was charged with 36.1 g of pure water and 29.4 g (0.30 mol) of maleic anhydride, and the contents were heated to 90° C. under stirring. After the heating, 14.0 g (0.17 mol) of 48% NaOH and 6.0 mg of Mohr's salt were added thereto. After the addition, the solution had a pH of 0.4. Subsequently, 65.3 g (0.72 mol) of 80% AA, 29.0 g (0.12 mol) of AGE-DBA, 48.0 g (6.0 g per mole of the monomers added) of 15% NaPS, and 29.5 g (6.0 g per mole of the monomers added) of 35% SBS were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA was added over 150 minutes, AGE-DBA was added over 120 minutes, 15% NaPS was added over 180 minutes, and 35% SBS was added over 150 minutes. During the addition, each component was continuously added dropwise at a constant rate.

(33) After the dropwise addition, the reaction solution was further maintained at 90° C. and aged for 30 minutes to complete the polymerization. The reaction solution immediately after the completion of the polymerization had a pH of 2.3. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 41.2 g (i.e., 0.49 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (3) having a solids concentration of 38 mass % and a final degree of neutralization of 50 mol % was obtained. The reaction ratio of AGE-DBA was 96%. The polymer (3) had a Mw of 8600, a Ca trapping ability of 462, and a carbon black dispersing ability of 1.00.

Example 4

(34) A 500-mL glass separable flask equipped with a reflux condenser and a stirrer was charged with 40.9 g of pure water and 39.0 g (0.30 mol) of itaconic acid, and the contents were heated to 90° C. under stirring. After the heating, 14.0 g (0.17 mol) of 48% NaOH and 7.0 mg of Mohr's salt were added thereto. After the addition, the solution had a pH of 0.7. Subsequently, 83.6 g (0.93 mol) of 80% AA, 19.6 g (0.08 mol) of AGE-DBA, 52.4 g (6.0 g per mole of the monomers added) of 15% NaPS, and 22.4 g (6.0 g per mole of the monomers added) of 35% SBS were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA and AGE-DBA were each added over 120 minutes, 15% NaPS was added over 150 minutes, and 35% SBS was added over 120 minutes. During the addition, each component was continuously added dropwise at a constant rate.

(35) After the dropwise addition, the reaction solution was further maintained at 90° C. and aged for 60 minutes to complete the polymerization. The reaction solution immediately after the completion of the polymerization had a pH of 3.0. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 49.7 g (i.e., 0.60 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (4) having a solids concentration of 39 mass % and a final degree of neutralization of 50 mol % was obtained. The reaction ratio of AGE-DBA was 90%. The polymer (4) had a Mw of 34400, a Ca trapping ability of 283, and a carbon black dispersing ability of 1.56.

Example 5

Synthesis of Monomer

(36) The following describes a method for synthesizing an iminodiacetic acid derivative monomer of AGE (AGE-IDA).

(37) A 1000 mL four-necked glass flask equipped with a reflux condenser and a stirrer (paddle blades) was charged with 151.7 g of pure water, 119.8 g of iminodiacetic acid, and 150.0 g of 48% NaOH, and the contents were heated to 60° C. under stirring. Then, 102.7 g of AGE was added over 60 minutes, and the contents were reacted for five hours. Thus, 50% AGE-IDA was obtained.

Synthesis of Polymer

(38) A 500-mL glass separable flask equipped with a reflux condenser and a stirrer was charged with 30.0 g of pure water and 34.3 g (0.35 mol) of maleic anhydride, and the contents were heated to 90° C. under stirring. After the heating, 16.3 g (0.20 mol) of 48% NaOH and 6.2 mg of Mohr's salt were added thereto. After the addition, the solution had a pH of 0.4. Subsequently, 87.0 g (1.0 mol) of 80% AA, 48.0 g (0.08 mol) of 50% AGE-IDA, 55.9 g (6.0 g per mole of the monomers added) of 15% NaPS, and 32.0 g (8.0 g per mole of the monomers added) of 35% SBS were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA and 50% AGE-IDA were each added over 120 minutes, 15% NaPS was added over 150 minutes, and 35% SBS was added over 110 minutes. During the addition, each component was continuously added dropwise at a constant rate.

(39) After the dropwise addition, the reaction solution was further maintained at 90° C. and aged for 60 minutes to complete the polymerization. The reaction solution immediately after the completion of the polymerization had a pH of 2.1. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 53.1 g (i.e., 0.64 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (5) having a solids concentration of 48 mass % and a final degree of neutralization of 50 mol % was obtained. The reaction ratio of AGE-IDA was 92%. The polymer (5) had a Mw of 17000, a Ca trapping ability of 328, and a carbon black dispersing ability of 0.50.

Example 6

Synthesis of Monomer

(40) The following describes a method for synthesizing a diethanolamine derivative monomer of AGE (AGE-DEA). A 1000 mL four-necked glass flask equipped with a reflux condenser and a stirrer (paddle blades) was charged with 235.9 g of diethanolamine, and the diethanolamine was heated to 60° C. under stirring. Then, 251.1 g of AGE was added over 60 minutes, and the contents were reacted for five hours. Thus, 100% AGE-DEA was obtained.

Synthesis of Polymer

(41) A 500-mL glass separable flask equipped with a reflux condenser and a stirrer was charged with 32.0 g of pure water and 34.3 g (0.35 mol) of maleic anhydride, and the contents were heated to 90° C. under stirring. After the heating, 16.3 g (0.20 mol) of 48% NaOH and 6.2 mg of Mohr's salt were added thereto. After the addition, the solution had a pH of 0.4. Subsequently, 87.0 g (1.0 mol) of 80% AA, 25.5 g (0.09 mol) of 80% AGE-DEA, 56.4 g (6.0 g per mole of the monomers added) of 15% NaPS, and 32.2 g (8.0 g per mole of the monomers added) of 35% SBS were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA and 80% AGE-DEA were each added over 120 minutes, 15% NaPS was added over 150 minutes, and 35% SBS was added over 110 minutes. During the addition, each component was continuously added dropwise at a constant rate.

(42) After the dropwise addition, the reaction solution was further maintained at 90° C. and aged for 60 minutes to complete the polymerization. The reaction solution immediately after the completion of the polymerization had a pH of 2.0. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 53.1 g (i.e., 0.64 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (6) having a solids concentration of 48 mass % and a final degree of neutralization of 50 mol % was obtained. The reaction ratio of AGE-DEA was 96%. The polymer (6) had a Mw of 10200, a Ca trapping ability of 281, and a carbon black dispersing ability of 0.34.

Example 7

Synthesis of Monomer

(43) The following describes a method for synthesizing a trimethylamine derivative monomer of AGE (AGE-TMA).

(44) A 1000 mL four-necked glass flask equipped with a reflux condenser and a stirrer (paddle blades) was charged with 104.9 g of pure water and 191.1 g of a trimethylamine hydrochloride, and the contents were heated to 50° C. under stirring. Then, 228.3 g of AGE was added over 120 minutes, and the contents were reacted for two hours. Thus, 80% AGE-TMA was obtained.

Synthesis of Polymer

(45) A 500-mL glass separable flask equipped with a reflux condenser and a stirrer was charged with 36.2 g of pure water and 29.4 g (0.30 mol) of maleic anhydride, and the contents were heated to 90° C. under stirring. After the heating, 14.0 g (0.17 mol) of 48% NaOH and 5.2 mg of Mohr's salt were added thereto. After the addition, the solution had a pH of 0.4. Subsequently, 74.6 g (0.8 mol) of 80% AA, 21.8 g (0.08 mol) of 80% AGE-TMA, 48.4 g (6.0 g per mole of the monomers added) of 15% NaPS, and 13.8 g (4.0 g per mole of the monomers added) of 35% SBS were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA and 80% AGE-TMA were each added over 120 minutes, 15% NaPS was added over 150 minutes, and 35% SBS was added over 110 minutes. During the addition, each component was continuously added dropwise at a constant rate.

(46) After the dropwise addition, the reaction solution was further maintained at 90° C. and aged for 60 minutes to complete the polymerization. The reaction solution immediately after the completion of the polymerization had a pH of 1.9. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 45.5 g (i.e., 0.55 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (7) having a solids concentration of 47 mass % and a final degree of neutralization of 50 mol % was obtained. The reaction ratio of AGE-TMA was 98%. The polymer (7) had a Mw of 8500, a Ca trapping ability of 294, and a carbon black dispersing ability of 0.20.

Example 8

(47) A 500-mL glass separable flask equipped with a reflux condenser and a stirrer was charged with 68.0 g of pure water and 53.9 g (0.55 mol) of maleic anhydride, and the contents were heated to 100° C. under stirring. After the heating, 36.7 g (0.44 mol) of 48% NaOH and 5.2 mg of Mohr's salt were added thereto. After the addition, the solution had a pH of 0.4. Subsequently, 49.5 g (0.5 mol) of 80% AA, 41.2 g (0.06 mol) of a 33% aqueous solution of sodium 2-acrylamide-2-methylpropane sulfonate (hereinafter, abbreviated as 33% AMPS), 14.9 g (0.06 mol) of AGE-DBA, 28.6 g (3.5 g per mole of the monomers added) of 15% NaPS, and 10.5 g (3.0 g per mole of the monomers added) of 35% H.sub.2O.sub.2 were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA and 33% AMPS were each added over 150 minutes, 15% NaPS was added over 180 minutes, and AGE-DBA and 35% H.sub.2O.sub.2 were each added over 120 minutes. During the addition, each component was continuously added dropwise at a constant rate.

(48) After the dropwise addition, the reaction solution was further maintained at 100° C. and aged for 60 minutes to complete the polymerization. The reaction solution immediately after the completion of the polymerization had a pH of 2.3. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 32.1 g (i.e., 0.38 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (8) having a solids concentration of 46 mass % and a final degree of neutralization of 50 mol % was obtained. The reaction ratio of AGE-DBA was 93%. The polymer (8) had a Mw of 7700, a Ca trapping ability of 312, and a carbon black dispersing ability of 0.56.

Comparative Example 1

(49) A 1.0 L glass separable flask equipped with a reflux condenser and a stirrer was charged with 100.0 g of pure water, and the water was heated to 70° C. under stirring. After the heating, 4.3 mg of Mohr's salt was added. Subsequently, 189.0 g (2.10 mol) of 80% AA, 50.4 g (0.21 mol) of AGE-DBA, 92.3 g (6.0 g per mole of the monomers added) of 15% NaPS, and 62.6 g (9.5 g per mole of the monomers added) of a 35% aqueous solution of sodium bisulfite (hereinafter, abbreviated as 35% SBS) were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA and 35% SBS were each added over 180 minutes, AGE-DBA was added over 170 minutes, and 15% NaPS was added over 190 minutes. During the addition, each component was continuously added dropwise at a constant rate.

(50) After the dropwise addition, the reaction solution was further maintained at 70° C. and aged for 30 minutes to complete the polymerization. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 122.5 g (i.e., 1.47 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (9) having a solids concentration of 44 mass % and a final degree of neutralization of 70 mol % was obtained. The polymer (9) had a Mw of 14700, a Ca trapping ability of 185, and a carbon black dispersing ability of 1.15.

Comparative Example 2

(51) A 1.0 L glass separable flask equipped with a reflux condenser and a stirrer was charged with 100.0 g of pure water, and the water was heated to 85° C. under stirring. After the heating, 13.3 mg of Mohr's salt was added. Subsequently, 183.8 g (2.04 mol) of 80% AA, 60.6 g (0.112 mol) of 40% HAPS, 42.0 g (0.173 mol) of AGE-DBA, 93.0 g (6.0 g per mole of the monomers added) of 15% NaPS, and 39.9 g (6.0 g per mole of the monomers added) of 35% SBS were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA was added over 180 minutes, 40% HAPS and AGE-DBA were each added over 120 minutes, 15% NaPS was added over 210 minutes, and 35% SBS was added over 175 minutes. During the addition, each component was continuously added dropwise at a constant rate.

(52) After the dropwise addition, the reaction solution was further maintained at 85° C. and aged for 30 minutes to complete the polymerization. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 111.7 g (i.e., 1.34 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (10) having a solids concentration of 42 mass % and a final degree of neutralization of 70 mol % was obtained. The polymer (10) had a Mw of 9400, a Ca trapping ability of 144, and a carbon black dispersing ability of 1.28.

Comparative Example 3

(53) A 1.0 L glass separable flask equipped with a reflux condenser and a stirrer was charged with 100.0 g of pure water, and the water was heated to 85° C. under stirring. After the heating, 14.1 mg of Mohr's salt was added. Subsequently, 210.0 g (2.33 mol) of 80% AA, 60.6 g (0.112 mol) of 40% HAPS, 21.0 g (0.112 mol) of a normal butanol adduct of allyl glycidyl ether (hereinafter, abbreviated as AGE-BuOH), 102.3 g (6.0 g per mole of the monomers added) of 15% NaPS, and 43.8 g (6.0 g per mole of the monomers added) of 35% SBS were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA was added over 180 minutes, 40% HAPS and AGE-BuOH were each added over 120 minutes, 15% NaPS was added over 210 minutes, and 35% SBS was added over 175 minutes. During the addition, each component was continuously added dropwise at a constant rate.

(54) After the dropwise addition, the reaction solution was further maintained at 85° C. and aged for 30 minutes to complete the polymerization. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 128.8 g (i.e., 1.55 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (11) having a solids concentration of 42 mass % and a final degree of neutralization of 70 mol % was obtained. The polymer (11) had a Mw of 7200, a Ca trapping ability of 185, and a carbon black dispersing ability of 0.90.

Comparative Example 4

(55) A 500-mL glass separable flask equipped with a reflux condenser and a stirrer was charged with 89.8 g of pure water, and the water was heated to 85° C. under stirring. After the heating, 7.0 mg of Mohr's salt was added. Subsequently, 126.1 g (1.40 mol) of 80% AA, 17.8 g (0.07 mol) of AGE-DBA, 23.6 g (2.4 g per mole of the monomers added) of 15% NaPS, and 25.8 g (3.5 g per mole of the monomers added) of 20% SBS were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA and AGE-DBA were each added over 180 minutes, 20% SBS was added over 200 minutes, and 15% NaPS was added over 210 minutes. During the addition, each component was continuously added dropwise at a constant rate.

(56) After the dropwise addition, the reaction solution was further maintained at 85° C. and aged for 30 minutes to complete the polymerization. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 70.0 g (i.e., 0.84 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (12) having a solids concentration of 45 mass % and a final degree of neutralization of 60 mol % was obtained. The polymer (12) had a Mw of 11400, a Ca trapping ability of 189, and a carbon black dispersing ability of 2.26.

Comparative Example 5

(57) A 500-mL glass separable flask equipped with a reflux condenser and a stirrer was charged with 27.4 g of pure water and 29.4 g (0.30 mol) of maleic anhydride, and the contents were heated to 90° C. under stirring. After the heating, 14.0 g (0.17 mol) of 48% NaOH and 6.0 mg of Mohr's salt were added. Subsequently, 96.4 g (1.07 mol) of 80% AA, 54.8 g (6.0 g per mole of the monomers added) of 15% NaPS, and 15.7 g (4.0 g per mole of the monomers added) of 35% SBS were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA was added over 120 minutes, 15% NaPS was added over 150 minutes, and 35% SBS was added over 120 minutes. During the addition, each component was continuously added dropwise at a constant rate.

(58) After the dropwise addition, the reaction solution was further maintained at 90° C. and aged for 60 minutes to complete the polymerization. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 69.5 g (i.e., 0.83 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (13) having a solids concentration of 48 mass % and a final degree of neutralization of 60 mol % was obtained. The polymer (13) had a Mw of 8200, a Ca trapping ability of 339, and a carbon black dispersing ability of 0.01.

Comparative Example 6

(59) A 500-mL glass separable flask equipped with a reflux condenser and a stirrer was charged with 81.4 g pure water, and the water was heated to 85° C. under stirring. After the heating, 7.4 mg of Mohr's salt was added. Subsequently, 126.1 g (1.40 mol) of 80% AA, 32.4 g (0.06 mol) of 40% HAPS, 14.5 g (0.06 mol) of AGE-DBA, 24.3 g (2.4 g per mole of the monomers added) of 15% NaPS, and 26.6 g (3.5 g per mole of the monomers added) of 20% SBS were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA was added over 180 minutes, 40% HAPS and AGE-DBA were each added over 120 minutes, 15% NaPS was added over 210 minutes, and 35% SBS was added over 180 minutes. During the addition, each component was continuously added dropwise at a constant rate.

(60) After the dropwise addition, the reaction solution was further maintained at 85° C. and aged for 30 minutes to complete the polymerization. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 70.0 g (i.e., 0.84 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (14) having a solids concentration of 41 mass % and a final degree of neutralization of 60 mol % was obtained. The polymer (14) had a Mw of 13200, a Ca trapping ability of 192, and a carbon black dispersing ability of 1.91.

Comparative Example 7

(61) A 2.5 L stainless steel separable flask equipped with a reflux condenser and a stirrer was charged with 110.0 g of pure water and 216.2 g (2.20 mol) of maleic anhydride, and the contents were heated to 100° C. under stirring. After the heating, 270.0 g (3.24 mol) of 48% NaOH and 267.1 g (0.49 mol) of 40% HAPS were added. Subsequently, 198.6 g (2.20 mol) of 80% AA, 78.4 g (2.4 g per mole of the monomers added) of 15% NaPS, 28.0 g (2.0 g per mole of the monomers added) of 35% H.sub.2O.sub.2, and 147.8 g of pure water were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA and 15% NaPS were each added over 120 minutes, 35% H.sub.2O.sub.2 was added over 75 minutes, and pure water was added over 120 minutes. During the addition, each component was continuously added dropwise at a constant rate.

(62) After the dropwise addition, the reaction solution was further maintained at 100° C. and aged for 35 minutes to complete the polymerization. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 136.6 g (i.e., 1.64 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (15) having a solids concentration of 42 mass % and a final degree of neutralization of 79 mol % was obtained. The polymer (15) had a Mw of 8300, a Ca trapping ability of 367, and a carbon black dispersing ability of 0.01.

Comparative Example 8

(63) A 2.5 L stainless steel separable flask equipped with a reflux condenser and a stirrer was charged with 110.0 g of pure water and 216.2 g (2.205 mol) of maleic anhydride, and the contents were heated to 100° C. under stirring. After the heating, 277.9 g (3.33 mol) of 48% NaOH, 133.5 g (0.245 mol) of 40% HAPS, and 59.63 g (0.245 mol) of AGE-DBA were added thereto. After the addition, the solution had a pH of 7.2. Subsequently, 198.6 g (2.205 mol) of 80% AA, 98.0 g (3.0 g per mole of the monomers added) of 15% NaPS, 33.6 g (2.4 g per mole of the monomers added) of a 35% aqueous solution of hydrogen peroxide (hereinafter, abbreviated as 35% H.sub.2O.sub.2), and 147.8 g of pure water were added dropwise to the polymerization reaction system through different nozzles under stirring. The addition times of these components were as follows: 80% AA and pure water were each added over 120 minutes, 15% NaPS was added over 150 minutes, and 35% H.sub.2O.sub.2 was added over 90 minutes. During the addition, each component was continuously added dropwise at a constant rate. The reaction solution had a pH of 5.9 both after 120 minutes and after 150 minutes from the start of dropwise addition.

(64) After the dropwise addition, the reaction solution was further maintained at 100° C. and aged for 35 minutes to complete the polymerization. The reaction solution immediately after the completion of the polymerization had a pH of 5.9. After the completion of the polymerization, the reaction solution was cooled and neutralized by gradually adding dropwise 136.6 g (i.e., 1.64 mol) of 48% NaOH to the reaction solution under stirring. Thus, a polymer (16) having a solids concentration of 42 mass % and a final degree of neutralization of 78 mol % was obtained. The reaction ratio of AGE-DBA was 13.5%.

(65) Table 1 shows the weight average molecular weight, the Ca trapping ability, and the carbon black dispersing ability of each of the polymers obtained in Examples 1 to 8 and Comparative Examples 1 to 7.

(66) In Table 1, MA means maleic acid.

(67) TABLE-US-00001 TABLE 1 Composition Composition ratio Ca trapping Carbon black of monomers of monomers (wt %) Mw ability dispersing ability Example 1 Polymer (1) AA/MA/AGE-DBA 54/31/15 9,500 294 0.77 Example 2 Polymer (2) AA/MA/AGE-DBA/HAPS 30/49/11/10 10,200 363 0.58 Example 3 Polymer (3) AA/MA/AGE-DBA 45/30/25 8,600 462 1.00 Example 4 Polymer (4) AA/Itaconic acid/AGE-DBA 53/31/16 34,400 283 1.56 Example 5 Polymer (5) AA/MA/AGE-IDA 52/30/18 17,000 328 0.50 Example 6 Polymer (6) AA/MA/AGE-DEA 53/31/16 10,200 281 0.34 Example 7 Polymer (7) AA/MA/AGE-TMA 53/31/16 8,500 294 0.20 Example 8 Polymer (8) AA/MA/AGE-DBA/AMPS 30/49/11/10 7,700 312 0.56 Comparative Polymer (9) AA/AGE-DBA 75/25 14,700 185 1.15 Example 1 Comparative Polymer (10) AA/AGE-DBA/HAPS 69/20/11 9,400 144 1.28 Example 2 Comparative Polymer (11) AA/AGE-BuOH/HAPS 79/10/11 7,200 185 0.90 Example 3 Comparative Polymer (12) AA/AGE-DBA 85/15 11,400 189 2.26 Example 4 Comparative Polymer (13) AA/MA 69/31 8,200 339 0.01 Example 5 Comparative Polymer (14) AA/AGE-DBA/HAPS 79/11/10 13,200 192 1.91 Example 6 Comparative Polymer (15) AA/MA/HAPS 30/49/21 8,300 367 0.01 Example 7

(68) The results of the examples and comparative examples demonstrate that the Ca trapping ability and the carbon black dispersing ability are both excellent in Examples 1 to 8, whereas in Comparative Examples 1 to 7, either the Ca trapping ability or the carbon black dispersing ability is excellent. Accordingly, the polymers of the present invention having the particular structure are excellent in both the Ca trapping ability and the carbon black dispersing ability.