Carboxyl group-containing polymer and composition containing the same

Abstract

The present invention provides a carboxyl group-containing polymer and a composition containing the polymer which exhibit excellent anti-soil redeposition ability in fabric washing. The carboxyl group-containing polymer includes specific ratios of a structure unit (a) derived from an ether bond-containing monomer (A), a structure unit (b) derived from a sulfonic acid group-containing monomer (B), and a structure unit (c) derived from an acrylic acid-based monomer (C), and has a specific weight average molecular weight. The carboxyl group-containing polymer composition contains the carboxyl group-containing polymer and a specific amount of a hydrogen sulfite adduct of the acrylic acid-based monomer (C).

Claims

1. A carboxyl group-containing polymer comprising: a structure unit (a) derived from an ether bond-containing monomer (A); a structure unit (b) derived from a sulfonic acid group-containing monomer (B); and a structure unit (c) derived from an acrylic acid-based monomer (C), wherein the structure unit (a) represented by the formula (1): ##STR00010## where R.sup.0 represents a hydrogen atom or a methyl group; R.sup.1 represents a CH.sub.2 group, a CH.sub.2CH.sub.2 group, or a direct bond; X represents a hydroxyl group or a group represented by the formula (2) or (3): ##STR00011## where R.sup.2 in the formula (2) and the formula (3) may be the same or different; R.sup.2 represent a C2-C4 alkylene group; n represents an average addition number of moles of an oxyalkylene group (—O—R.sup.2—) and is 0 to 2; and R.sup.3, R.sup.4 and R.sup.5 independently represent a C1-C4 alkyl group; Y represents a hydroxyl group or a group represented by the formula (2) or (3); and one of X and Y is a hydroxyl group and the other is a group represented by the formula (2) or (3); the structure unit (a) is present at a level of from 0.5 to 9% by mass based on 100% by mass of all structure units derived from all monomers in the carboxyl group-containing polymer; the structure unit (b) is present at a level of from 0.5 to 30% by mass based on 100% by mass of all the structure units derived from all the monomers in the carboxyl group-containing polymer; the structure unit (c) is present at a level of from 55 to 99% by mass based on 100% by mass of all the structure units derived from all the monomers in the carboxyl group-containing polymer; and the carboxyl group-containing polymer has a weight average molecular weight of 20,000 to 60,000.

2. A carboxyl group-containing polymer composition comprising: the carboxyl group-containing polymer according to claim 1; and an adduct of a hydrogen sulfite to an acrylic acid-based monomer (C), wherein the adduct is present at a level of 0.01 to 1.5% by mass based on 100% by mass of a solids content of the carboxyl group-containing polymer composition, and the adduct of a hydrogen sulfite to the acrylic acid-based monomer (C) is unpolymerized with the carboxyl group-containing polymer.

3. A method for preparing the carboxyl group-containing polymer of claim 1, comprising copolymerization of monomer materials including 0.5 to 9% by mass of an ether bond-containing monomer (A), 0.5 to 30% by mass of a sulfonic acid group-containing monomer (B) and 55 to 99% by mass of an acrylic acid-based monomer (C) based on 100% by mass of all the monomers, the ether bond-containing monomer (A) being represented by the formula (4): ##STR00012## wherein R.sup.0 represents a hydrogen atom or a methyl group; le represents a CH.sub.2 group, a CH.sub.2CH.sub.2 group, or a direct bond; X represents a hydroxyl group or a group represented by the formula (2) or (3): ##STR00013## wherein R.sup.2s, which may be the same or different, represent a C2-C4 alkylene group; n represents an average addition number of moles of an oxyalkylene group (—O—R.sup.2—) and is 0 to 2; and R.sup.3, R.sup.4 and R.sup.5 independently represent a C1-C4 alkyl group; Y represents a hydroxyl group or a group represented by the formula (2) or (3); and one of X and Y is a hydroxyl group and the other is a group represented by the formula (2) or (3), the copolymerization being performed using 1 to 15 g of a hydrogen sulfite and/or a compound capable of producing a hydrogen sulfite per mol of all the monomers.

4. The carboxyl group-containing polymer of claim 1, wherein the carboxyl group-containing polymer has a weight average molecular weight of 35,000-58,000 and an anti-soil redeposition ability in a range from 36.5%-45%.

5. The carboxyl group-containing polymer of claim 1, wherein the carboxyl group-containing polymer has a weight average molecular weight of 35,000-50,000.

Description

DESCRIPTION OF EMBODIMENTS

(1) The following description is offered to describe the present invention by way of Examples. The present invention, however, is not limited only to these examples. All parts are by mass unless otherwise specified, and all percentages are by mass unless otherwise specified.

(2) The monomers and reaction intermediates were quantified and measured for physical properties by the methods described below.

(3) <Measurement Condition of Weight Average Molecular Weight (GPC)>

(4) Measuring device: L-7000 series (product of Hitachi Ltd.)

(5) Detector: HITACHI RI Detector, L-7490

(6) Column: SHODEX Asahipak GF-310-HQ, GF-710-HQ, GF-1G 7B (products of Showa Denko K. K.)

(7) Column temperature: 40° C.

(8) Flow velocity: 0.5 ml/min

(9) Calibration curve: Polyacrylic acid standard (Product of Sowakagaku Co., Ltd)

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

(11) <Quantification of Ether Bond-Containing Monomer, Sulfonic Acid Group-Containing Monomer, Acrylic Acid-Based Monomer, and Hydrogen Sulfite Adduct>

(12) The ether bond-containing monomer, the sulfonic acid group-containing monomer, the acrylic acid-based monomer, and the hydrogen sulfite adduct were quantified by liquid chromatography under the following conditions.

(13) Measuring device: L-7000 series (product of Hitachi Ltd.)

(14) Detector: UV detector, L-7400 (product of Hitachi Ltd.)

(15) Column: SHODEX RSpak DE-413 (product of Showa Denko K. K.)

(16) Temperature: 40.0° C.

(17) Eluent: 0.1% phosphoric acid aqueous solution

(18) Flow velocity: 1.0 ml/min

(19) <Measurement of Solids Content>

(20) A mixture of 1.0 g of a carboxyl group-containing polymer composition of the present invention and 1.0 g of water was left in an oven heated to 130° C. in nitrogen atmosphere for one hour so as to be dried. The solids content (%) and volatile component content (%) were calculated from the mass change before and after the drying step.

Example 1

(21) (1) Synthesis of Monomers

(22) In a 500-mL four-necked glass flask equipped with a reflux condenser and a stirrer (paddle blade), n-butylalcohol (370.0 g) and sodium hydroxide pellets (4.27 g) were stirred while heating to 60° C. Next, allyl glycidyl ether (hereinafter, referred to as AGE) (57.0 g) was added thereto over 30 minutes, and then the mixture was reacted for five hours. The resulting solution was transferred to a 1000-ml recovery flask, and the solvent therein was removed by a rotary evaporator. To the residue was added a 20% by mass sodium chloride aqueous solution (200.0 g), and the resulting aqueous solution was transferred to a 500-ml separating funnel. The solution was shaken enough and then left standing until the solution was separated into phases. The lower phase was removed and the upper phase was transferred into a 300-ml recovery flask to remove the solvent therein by a rotary evaporator. The precipitated salt was removed by filtration, and thus a polymer (1) was obtained.

(23) (2) Polymerization

(24) In a 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (128.4 g) and Mohr's salt (0.0187 g) were stirred while heating to 85° C. Thus, a polymerization reaction system was built. Next, an 80% acrylic acid aqueous solution (hereinafter, also referred to as 80% AA) (270.0 g), a 40% aqueous solution of sodium 3-allyloxy-2-hydroxypropanesulfonate (hereinafter, also referred to as 40% HAPS) (192.0 g), the monomer (1) (15.0 g), a 15% sodium persulfate aqueous solution (hereinafter, also referred to as 15% NaPS) (68.7 g), and a 35% sodium hydrogen sulfite aqueous solution (hereinafter, also referred to as 35% SBS) (19.6 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at 85° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, the monomer (1), 15% NaPS, and 35% SBS were 180 minutes, 120 minutes, 120 minutes, 190 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.

(25) The reaction solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of polymerization, the polymerization reaction solution was cooled with stirring, and then neutralized by gradually adding dropwise a 48% sodium hydroxide aqueous solution (hereinafter, also referred to as 48% NaOH) (193.3 g).

(26) Through these steps, a polymer aqueous solution (1) containing a polymer (1) of the present invention was prepared. The solids content of the polymer aqueous solution (1) was 45%, and the weight average molecular weight of the polymer (1) was 35,000.

Example 2

(27) (1) Synthesis of Monomers

(28) In a 2-L four-necked glass flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (491.0 g) and di-n-butylamine (258.0 g) were stirred under purging with nitrogen while the liquid temperature was controlled to 50° C. Subsequently, AGE (232.8 g) was gradually added dropwise thereto over two hours with stirring. The liquid temperature was maintained at 50° C. to 60° C. After the completion of drop-wise addition, the resulting mixture was matured for two hours while the liquid temperature was maintained at 60° C. After cooled to room temperature, the liquid was transferred to a separating funnel and left standing. As a result, the liquid was separated into two phases. The lower aqueous phase was removed. The upper phase was washed with pure water. The resulting liquid was transferred to a recovery flask, and water therein was completely removed by a rotary evaporator. In this manner, a monomer (2) was obtained.

(29) (2) Polymerization

(30) In a 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (128.6 g) and Mohr's salt (0.0186 g) were stirred while heating to 85° C. Thus, a polymerization reaction system was built. Next, 80% AA (270.0 g), 40% HAPS (192.0 g), the monomer (2) (15.0 g), 15% NaPS (68.3 g), and 35% SBS (14.6 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at 85° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, the monomer (2), 15% NaPS, and 35% SBS were 180 minutes, 150 minutes, 120 minutes, 190 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.

(31) The reaction solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of polymerization, the polymerization reaction solution was cooled with stirring, and then neutralized by gradually adding dropwise 48% NaOH (193.3 g).

(32) Through these steps, a polymer aqueous solution (2) containing a polymer (2) of the present invention was prepared. The solids content of the polymer aqueous solution (2) was 45%, and the weight average molecular weight of the polymer (2) was 35,000.

Example 3

(33) In a 1000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (146.8 g) and Mohr's salt (0.0186 g) were stirred while heating to 85° C. Thus, a polymerization reaction system was built. Next, 80% AA (270.0 g), 40% HAPS (150.2 g), the monomer (1) (30.0 g), 15% NaPS (68.7 g), and 35% SBS (19.6 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at 85° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, the monomer (1), 15% NaPS, and 35% SBS were 180 minutes, 130 minutes, 140 minutes, 190 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.

(34) The reaction solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of polymerization, the polymerization reaction solution was cooled with stirring, and then neutralized by gradually adding dropwise 48% NaOH (197.5 g).

(35) Through these steps, a polymer aqueous solution (3) containing a polymer (3) of the present invention was prepared. The solids content of the polymer aqueous solution (3) was 45%, and the weight average molecular weight of the polymer (3) was 46,000.

Example 4

(36) In a 2000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (184.1 g) and Mohr's salt (0.0252 g) were stirred while heating to 85° C. Thus, a polymerization reaction system was built. Next, 80% AA (400.0 g), 40% HAPS (166.9 g), the monomer (1) (20.0 g), 15% NaPS (102.4 g), and 35% SBS (22.2 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at 85° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, the monomer (1), 15% NaPS, and 35% SBS were 180 minutes, 120 minutes, 150 minutes, 200 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.

(37) The reaction solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of polymerization, the polymerization reaction solution was cooled with stirring, and then neutralized by gradually adding dropwise 48% NaOH (298.2 g).

(38) Through these steps, a polymer aqueous solution (4) containing a polymer (4) of the present invention was prepared. The solids content of the polymer aqueous solution (4) was 45%, and the weight average molecular weight of the polymer (4) was 35,000.

Example 5

(39) In a 2000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (222.5 g) and Mohr's salt (0.0249 g) were stirred while heating to 85° C. Thus, a polymerization reaction system was built. Next, 80% AA (450.0 g), 40% HAPS (55.6 g), the monomer (1) (20.0 g), 15% NaPS (111.1 g), and 35% SBS (22.3 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at 85° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, the monomer (1), 15% NaPS, and 35% SBS were 180 minutes, 150 minutes, 150 minutes, 200 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.

(40) The reaction solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of polymerization, the polymerization reaction solution was cooled with stirring, and then neutralized by gradually adding dropwise 48% NaOH (298.2 g).

(41) Through these steps, a polymer aqueous solution (5) containing a polymer (5) of the present invention was prepared. The solids content of the polymer aqueous solution (5) was 45%, and the weight average molecular weight of the polymer (5) was 37,000.

Example 6

(42) In a 2000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (184.1 g) and Mohr's salt (0.0251 g) were stirred while heating to 85° C. Thus, a polymerization reaction system was built. Next, 80% AA (400.0 g), 40% HAPS (166.9 g), the monomer (1) (20.0 g), 15% NaPS (102.4 g), and 35% SBS (18.0 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at 85° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, the monomer (1), 15% NaPS, and 35% SBS were 180 minutes, 120 minutes, 150 minutes, 200 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.

(43) The reaction solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of polymerization, the polymerization reaction solution was cooled with stirring, and then neutralized by gradually adding dropwise 48% NaOH (298.2 g).

(44) Through these steps, a polymer aqueous solution (6) containing a polymer (6) of the present invention was prepared. The solids content of the polymer aqueous solution (6) was 45%, and the weight average molecular weight of the polymer (6) was 47,000.

Example 7

(45) In a 2000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (187.8 g) and Mohr's salt (0.0251 g) were stirred while heating to 85° C. Thus, a polymerization reaction system was built. Next, 80% AA (400.0 g), 40% HAPS (166.9 g), the monomer (1) (20.0 g), 15% NaPS (97.2 g), and 35% SBS (20.8 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at 85° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, the monomer (1), 15% NaPS, and 35% SBS were 180 minutes, 120 minutes, 150 minutes, 190 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.

(46) The reaction solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of polymerization, the polymerization reaction solution was cooled with stirring, and then neutralized by gradually adding dropwise 48% NaOH (298.2 g).

(47) Through these steps, a polymer aqueous solution (7) containing a polymer (7) of the present invention was prepared. The solids content of the polymer aqueous solution (7) was 45%, and the weight average molecular weight of the polymer (7) was 39,000.

Example 8

(48) In a 2000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (130.2 g) and Mohr's salt (0.0185 g) were stirred while heating to 85° C. Thus, a polymerization reaction system was built. Next, 80% AA (270.0 g), 40% HAPS (192.0 g), the monomer (1) (15.0 g), 15% NaPS (68.7 g), and 35% SBS (9.8 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at 85° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, the monomer (1), 15% NaPS, and 35% SBS were 180 minutes, 120 minutes, 150 minutes, 190 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.

(49) The reaction solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of polymerization, the polymerization reaction solution was cooled with stirring, and then neutralized by gradually adding dropwise 48% NaOH (193.3 g).

(50) Through these steps, a polymer aqueous solution (8) containing a polymer (8) of the present invention was prepared. The solids content of the polymer aqueous solution (8) was 45%, and the weight average molecular weight of the polymer (8) was 58,000.

Example 9

(51) In a 2000 mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (280.4 g) and Mohr's salt (0.0352 g) were stirred while heating to 85° C. Thus, a polymerization reaction system was built. Next, 80% AA (548.6 g), 40% HAPS (185.5 g), the monomer (1) (50.0 g), 15% NaPS (134.1 g), and 35% SBS (55.5 g) were separately added drop-wise through different nozzles to the polymerization reaction system maintained at 85° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, the monomer (1), 15% NaPS, and 35% SBS were 180 minutes, 150 minutes, 150 minutes, 200 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.

(52) The reaction solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of polymerization, the polymerization reaction solution was cooled with stirring, and then neutralized by gradually adding drop-wise 48% NaOH (413.3 g).

(53) Through these steps, a polymer aqueous solution (9) containing a polymer (9) of the present invention was prepared. The solids content of the polymer aqueous solution (9) was 45%, and the weight average molecular weight of the polymer (9) was 22,000. Polymer (9) comprises 9% by mass of a structure unit (a), 12% by mass of a structure unit (b), and 79% by mass of a structure unit (c).

Comparative Example 1

(54) In a 2000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (125.7 g) and Mohr's salt (0.0190 g) were stirred while heating to 85° C. Thus, a polymerization reaction system was built. Next, 80% AA (270.0 g), 40% HAPS (192.0 g), the monomer (1) (15.0 g), 15% NaPS (68.7 g), and 35% SBS (34.3 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at 85° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, the monomer (1), 15% NaPS, and 35% SBS were 180 minutes, 120 minutes, 150 minutes, 190 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.

(55) The reaction solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of polymerization, the polymerization reaction solution was cooled with stirring, and then neutralized by gradually adding dropwise 48% NaOH (193.3 g).

(56) Through these steps, a comparative polymer aqueous solution (1) containing a comparative polymer (1) was prepared. The solids content of the comparative polymer aqueous solution (1) was 45%, and the weight average molecular weight of the comparative polymer (1) was 17,000.

Comparative Example 2

(57) (1) Synthesis of Monomer

(58) In a 500-mL glass separable flask equipped with a stirrer (paddle blade), Newcol 2305 (ethylene oxide (5 mol) adducts of C12-C13 alcohols from Nippon Nyukazai Co., Ltd., 81.2 g) and potassium hydroxide (hereinafter, also referred to as KOH, 16.8 g) were stirred under purging with nitrogen while heating to 120° C. This state was continued for one hour to remove water in the reaction system. Next, a reflux condenser was attached to the flask, and the flask was cooled to 60° C. Methallyl chloride (hereinafter, also referred to as MLC) (27.0 g) was added thereto over 30 minutes, and then the mixture was reacted for five hours. To the resulting solution was added pure water (200.0 g), and then the obtained aqueous solution was cooled to room temperature, and transferred to a 500-ml separating funnel. The aqueous solution was left standing until the solution was separated into phases. The lower phase was removed, and the upper phase was transferred to a 300-ml recovery flask to remove the solvent therein by a rotary evaporator. The precipitated salt was removed by filtration, and thus a monomer (3) was obtained.

(59) (2) Polymerization

(60) In a 2000-mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade), pure water (168.6 g) and Mohr's salt (0.0223 g) were stirred while heating to 85° C. Thus, a polymerization reaction system was built. Next, 80% AA (360.0 g), 40% HAPS (138.5 g), the monomer (3) (17.8 g), 15% NaPS (85.9 g), and 35% SBS (18.4 g) were separately added dropwise through different nozzles to the polymerization reaction system maintained at 85° C., with stirring. The drop-wise addition times of 80% AA, 40% HAPS, the monomer (3), 15% NaPS, and 35% SBS were 180 minutes, 120 minutes, 120 minutes, 190 minutes, and 175 minutes, respectively. The drop-wise addition of each solution was continuously performed at a constant rate.

(61) The reaction solution was maintained (matured) at 85° C. for 30 minutes after the completion of drop-wise addition of 80% AA. In this manner, polymerization was completed. After the completion of the polymerization, the polymerization reaction solution was cooled with stirring, and then was neutralized with 48% NaOH (269.5 g).

(62) Through these steps, a comparative polymer aqueous solution (2) containing a comparative polymer (2) was prepared. The solids content of the comparative polymer aqueous solution (2) was 45%; the weight average molecular weight of the comparative polymer (2) was 32,000; and the anti-soil redeposition ability of the comparative polymer (2) was 32.6%.

(63) <Anti-Soil Redeposition Ability Test/Carbon Black>

(64) An anti-soil redeposition ability test was performed with carbon black in the following procedure.

(65) (1) Cotton cloth available from Testfabrics Inc. was cut into 5 cm×5 cm white cloth samples. The degree of whiteness was determined for the white cloth samples by measuring the reflectance with a colorimetric color difference meter (SE2000, product of Nippon Denshoku Industries Co., Ltd.).

(66) (2) Pure water was added to calcium chloride dihydrate (8.82 g) such that hard water (20 kg) was prepared.

(67) (3) A mixture (90.0 g) was prepared by adding pure water to sodium dodecylbenzensulfonate (4 g), sodium hydrogen carbonate (4.75 g), and sodium sulfate (4 g) and adjusted to pH 10 with a sodium hydroxide aqueous solution. Pure water was further added thereto such that a surfactant aqueous solution (100.0 g in total) was prepared.

(68) (4) A tergotmeter was set at 25° C. The hard water (1 L), the surfactant aqueous solution (2.5 g), a 0.4% (based on the solids content) polymer aqueous solution (2.5 g), zeolite (0.075 g), and carbon black (0.05 g) were stirred for one minute in a pot at 100 rpm. Subsequently, seven white cloth samples were put into the mixture, and the mixture was stirred for ten minutes at 100 rpm.

(69) (5) The white cloth samples were wrung by hand, and hard water (1 L) at 25° C. was poured into the pot and stirred at 100 rpm for two minutes.

(70) (6) The white cloth samples were each covered with a piece of cloth and dried by ironing while wrinkles were smoothed. The cloth samples were measured again for reflectance as whiteness with the colorimetric difference meter.

(71) (7) The anti-soil redeposition ratio was determined from the following equation, based on the measurement results.
Anti-soil redeposition ratio (%)=(whiteness of white cloth after washed)/(initial whiteness of white cloth)×100

(72) The mass ratios between the structure units (a), (b) and (c) in the polymers, the weight average molecular weights of the polymers, the 3-sulfopropionic acid (3SPA) contents (ppm), and the anti-soil redeposition ability of the compositions prepared in examples and comparative examples are shown in Table 1. In Table 1, “OBu” and “ABu.sub.2” refer to a n-butyl alcohol group in which a hydrogen atom of n-butyl alcohol is removed and a di-n-butylamine group in which a hydrogen atom of di-n-butylamine is removed, respectively.

(73) TABLE-US-00001 TABLE 1 Structure units Anti-soil (a)/(b)/(c) Weight average 3SPA redeposition ability Monomer (A) (% by mass) molecular weight (ppm) (%) Example 1 AGE-OBu 5/23/72 35,000 4,000 38.6 Example 2 AGE-ABu.sub.2 5/23/72 35,000 4,000 45 Example 3 AGE-OBu 10/18/72 46,000 3,000 37.8 Example 4 AGE-OBu 5/15/80 35,000 200 37.7 Example 8 AGE-OBu 5/23/72 58,000 2,000 36.5 Comparative AGE-OBu 5/23/72 17,000 5,000 32.9 Example 1

(74) The results of Examples and Comparative Examples demonstrate that the carboxyl group-containing polymers including a structure unit (a) derived from an ether bond-containing monomer (A), a structure unit (b) derived from a sulfonic acid group-containing monomer (B), and a structure unit (c) derived from an acrylic acid-based monomer (C) at specific levels, and having a specific weight average molecular weight, and the compositions containing these polymers and a specific amount of an adduct of a hydrogen sulfite to the acrylic acid-based monomer (C) have good anti-soil redeposition ability in hard water environment.

(75) Thus, it is presumed that the same mechanism of sufficiently producing good anti-soil redeposition ability works when any of the polymers and the compositions of the present invention having the above specific constitution.

(76) Therefore, it should be understood from the results of Examples, the present invention can be applied in the entire technical field of the present invention and the various modifications disclosed herein, and produce advantageous effects.