JP2014189669A - (meth)acrylic acid(salt)-dicarboxylic acid(salt) type copolymer and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a (meth)acrylic acid(salt)-dicarboxylic acid(salt) type copolymer which has a narrowed molecular weight distribution and excellent gelling resistance.SOLUTION: A (meth)acrylic acid(salt)-dicarboxylic acid(salt) type copolymer contains a structural unit originated from (meth)acrylic acid(salt) and a structural unit originated from a dicarboxylic acid(salt) and has sulfide bonds in the structure of the copolymer. The ratio of the structural unit originated from (meth)acrylic acid(salt) to the structural unit originated from dicarboxylic acid(salt), with the units constituting the copolymer, of 95:5 to 5:95, in terms of the mol ratio, and the weight average molecular weight of the copolymer is 500-200,000.

Description

  The present invention relates to a (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer and a method for producing the same. The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can be used in various applications such as detergent builders, dispersants, water treatment agents and the like.

  The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer obtained by polymerizing monomer components containing (meth) acrylic acid and dicarboxylic acid has a number of carboxyl groups or salts thereof. Excellent chelating action and dispersing action can be expressed. For this reason, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) -based copolymer can be used for various applications such as a detergent builder, a dispersant, a water treatment agent (see, for example, Patent Documents 1 and 2). ).

  However, in the conventional (meth) acrylic acid (salt) -dicarboxylic acid (salt) -based copolymer, the molecular weight distribution cannot be appropriately controlled, and in particular, those having a narrowed molecular weight distribution. It was difficult to obtain easily. If a (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer having a narrow molecular weight distribution can be easily obtained, (meth) acrylic acid whose molecular weight is appropriately controlled according to various uses Since it becomes possible to design and prepare a (salt) -dicarboxylic acid (salt) copolymer, positive development in various applications is expected.

  Moreover, in the conventional (meth) acrylic acid (salt) -dicarboxylic acid (salt) -based copolymer, the gelling ability is not sufficient, and particularly high gelling suppression such as detergent builder and water treatment agent is desired. There is a problem in use for applications.

JP 2000-53729 A JP 2000-143737 A

  An object of the present invention is to provide a (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer having a narrow molecular weight distribution and excellent gelation resistance, and a method for producing the same.

The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention is
A (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer comprising a structural unit derived from (meth) acrylic acid (salt) and a structural unit derived from dicarboxylic acid (salt),
Having a sulfide bond in the structure of the copolymer;
The molar ratio of the structural unit derived from the (meth) acrylic acid (salt) and the structural unit derived from the dicarboxylic acid (salt) constituting the copolymer is in the range of 95: 5 to 5:95,
The weight average molecular weight is 500-200000.

The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention is
A (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer comprising a structural unit derived from (meth) acrylic acid (salt) and a structural unit derived from dicarboxylic acid (salt),
Obtained through a polymerization step in the presence of a mercapto group-containing compound,
The molar ratio of the structural unit derived from the (meth) acrylic acid (salt) and the structural unit derived from the dicarboxylic acid (salt) constituting the copolymer is in the range of 95: 5 to 5:95,
The weight average molecular weight is 500-200000.

The method for producing the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention is as follows.
A method for producing a (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer according to the present invention,
A step of polymerizing a monomer essentially containing the (meth) acrylic acid (salt) and the dicarboxylic acid (salt) in the presence of a mercapto group-containing compound.

  The detergent composition of the present invention comprises the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention.

  The water treatment agent of the present invention contains the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention.

  According to the present invention, a (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer having a narrow molecular weight distribution and excellent gelation resistance can be provided. Since the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention exhibits excellent gelation resistance, it is suitably used for water-soluble polymer applications such as cleaning builders and water treatment agent applications. can do.

≪ (Meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer≫
The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention includes a structural unit derived from (meth) acrylic acid (salt) and a structural unit derived from dicarboxylic acid (salt). In the present specification, “(meth) acryl” means acryl and / or methacryl, and “(meth) acrylate” means acrylate and / or methacrylate. In the present specification, “(meth) acrylic acid (salt)” means (meth) acrylic acid and / or (meth) acrylate, and “dicarboxylic acid (salt)” means dicarboxylic acid. Means acid and / or dicarboxylate.

  The “salt” is a salt of a carboxyl group represented by COOM, and M is a hydrogen atom, a metal atom, an ammonium group (constituting an ammonium salt), or an organic amino group (constituting an organic amine salt). is there. Examples of the metal atom include alkali metals such as sodium and potassium, alkaline earth metals such as calcium, and transition metals such as iron. Examples of the organic amine salt include primary to quaternary amine salts such as methylamine salt, n-butylamine salt, monoethanolamine salt, dimethylamine salt, diethanolamine salt, morpholine salt, and trimethylamine salt. M is a hydrogen atom, a sodium atom, an excellent effect of improving the detergency when the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention is used for washing applications, etc. A potassium atom is preferred.

The structural unit derived from (meth) acrylic acid (salt) is a structural unit of a polymer structure formed by polymerization of (meth) acrylic acid (salt), and — [CH ₂ —CR ¹ (COOM ¹ )]-. Here, R ¹ is a hydrogen atom or a methyl group. M ¹ is a hydrogen atom, a metal atom, an ammonium group (composing an ammonium salt), or an organic amino group (composing an organic amine salt), and is the same as M described above. Only one type of structural unit derived from (meth) acrylic acid (salt) may be used, or two or more types may be used.

The structural unit derived from dicarboxylic acid (salt) is a structural unit of a polymer structure formed by polymerization of dicarboxylic acid (salt). Examples of the dicarboxylic acid (salt) include maleic acid (salt), maleic anhydride (salt), fumaric acid (salt), itaconic acid (salt), itaconic anhydride (salt), and 2-methyleneglutaric acid (salt). Etc. The dicarboxylic acid (salt) is preferably maleic acid (salt). When the dicarboxylic acid (salt) is maleic acid (salt), the structural unit of the polymer structure formed by polymerizing the dicarboxylic acid (salt) is-[CH (COOM ² ) -CH (COOM ³ )] It is represented by −. Here, M ² and M ³ are a hydrogen atom, a metal atom, an ammonium group (constituting an ammonium salt), or an organic amino group (constituting an organic amine salt), and are the same as M described above. Only one type of structural unit derived from dicarboxylic acid (salt) may be used, or two or more types may be used.

  The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention is a structural unit other than a structural unit derived from (meth) acrylic acid (salt) and a structural unit derived from dicarboxylic acid (salt). The structural unit derived from a monomer may be included. Examples of such other monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4 Hydroxyl group-containing alkyl (meth) acrylates such as hydroxybutyl (meth) acrylate and α-hydroxymethylethyl (meth) acrylate; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, ( Alkyl (meth) acrylates which are esters of alkyl groups having 1 to 18 carbon atoms of (meth) acrylic acid such as cyclohexyl (meth) acrylate and lauryl (meth) acrylate; dimethylaminoethyl (meth) acrylate or its quaternary Acrylic group-containing acrylate Amide group-containing monomers such as (meth) acrylamide, dimethylacrylamide and isopropylacrylamide; Vinyl esters such as vinyl acetate; Alkenes such as ethylene and propylene; Aromatic vinyl monomers such as styrene Maleimide derivatives such as maleimide, phenylmaleimide and cyclohexylmaleimide; nitrile group-containing vinyl monomers such as (meth) acrylonitrile; 2-acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid, (meth) allylsulfone Monomers having a sulfonic acid group such as acid, vinyl sulfonic acid, 2-hydroxy-3-allyloxy-1-propanesulfonic acid, 2-hydroxy-3-butenesulfonic acid, and salts thereof; vinylphosphonic acid, ( Phosphonic acids such as (meth) allylphosphonic acid Group-containing monomers; aldehyde group-containing vinyl monomers such as (meth) acrolein; alkyl vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether; polyalkylene glycol (meth) acrylate, monoalkoxy polyalkylene Polyalkylene glycol chain-containing monomers that are monomers having a structure in which 1 to 300 mol of alkylene oxide is added to unsaturated alcohol such as glycol (meth) acrylate, vinyl alcohol, (meth) allyl alcohol, and isoprenol; And monomers having other functional groups such as vinyl chloride, vinylidene chloride, allyl alcohol, vinyl pyrrolidone, and the like. These other monomers may be only one kind or two or more kinds.

  The ratio of the structural unit derived from (meth) acrylic acid (salt) and the structural unit derived from dicarboxylic acid (salt) constituting the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention is as follows: The molar ratio is 95: 5 to 5:95, preferably 92: 8 to 20:80, and more preferably 90:10 to 50:50. The ratio of the structural unit derived from (meth) acrylic acid (salt) and the structural unit derived from dicarboxylic acid (salt) constituting the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention is the above. By being within the range, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can have a narrower molecular weight distribution and more excellent gelation resistance.

  The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention is derived from a structural unit derived from (meth) acrylic acid (salt) and a dicarboxylic acid (salt) as a structural unit constituting the copolymer. Other structural units derived from monomers other than the structural unit may be included. In such a case, the ratio of the structural units derived from (meth) acrylic acid (salt) and the structural units derived from dicarboxylic acid (salt) and the structural units derived from other monomers is preferably a molar ratio, preferably It is 100: 0-80: 20, More preferably, it is 100: 0-85: 15, More preferably, it is 100: 0-90: 10. Sum of structural units derived from (meth) acrylic acid (salt) and structural units derived from dicarboxylic acid (salt) constituting the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention and others When the ratio of the structural unit derived from the monomer within the above range is within the above range, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention has a narrower molecular weight distribution. In addition, the gelation resistance can be more excellent. Other monomers will be described later.

  The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention has a weight average molecular weight of 500 to 200000, preferably 1000 to 150,000, more preferably 2000 to 120,000. Yes, particularly preferably 3000 to 100,000. When the weight average molecular weight of the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention falls within the above range, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) of the present invention. ) -Based copolymer can have a narrower molecular weight distribution and more excellent gelation resistance.

  The ratio of the carboxyl group (—COOH) and its salt (—COOM) in the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can be any appropriate ratio. In the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention, the ratio of the carboxyl group (—COOH) and its salt (—COOM) is the same as the carboxyl group (—COOH) and its salt. The proportion of carboxyl group (—COOH) in the total with (—COOM) is preferably 1 mol% to 99 mol%, more preferably 10 mol% to 99 mol%, and even more preferably 30 mol. % To 98 mol%, particularly preferably 50 mol% to 95 mol%. The ratio of the carboxyl group (—COOH) and its salt (—COOM) in the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention falls within the above range. The (meth) acrylic acid (salt) -dicarboxylic acid (salt) -based copolymer can be excellent in storage stability.

  The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention has a sulfide bond in its structure. Here, the sulfide bond is a bond represented by -S-. The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention has a sulfide bond in its structure, so that the (meth) acrylic acid (salt) -dicarboxylic acid (salt) of the present invention is present. ) -Based copolymer can be excellent in gelation resistance. The number of sulfide bonds in the structure of the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention may be only one, or may be two or more.

  The sulfide bond that the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention has in its structure is preferably obtained through a polymerization step in the presence of a mercapto group-containing compound. The mercapto group-containing compound may have a carboxylic acid group, a hydroxyl group, a sulfonic acid group, an amino group, a cationic group or the like as a functional group. The functional group may have a plurality of different types of functional groups. Examples of the mercapto group-containing compound include thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiosuccinic acid, thiomalic acid, mercaptoacetic acid, 2-mercaptoethanol, sodium 3-mercapto-1-propanesulfonate, Examples include cysteine and salts thereof. Only one type of mercapto group-containing compound may be used, or two or more types may be used. Preferably, it is a carboxylic acid group.

≪Method for producing (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer≫
The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention preferably polymerizes a monomer composition containing (meth) acrylic acid (salt) and dicarboxylic acid (salt). Can be obtained. The monomer composition mentioned here refers to a mixture of all monomers used for producing the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention.

  Examples of (meth) acrylic acid (salt) include acrylic acid, methacrylic acid, and salts thereof. The salt here is a carboxyl group salt represented by COOM as described above, and M is a hydrogen atom, a metal atom, an ammonium group (composing an ammonium salt), or an organic amino group (organic amine). Salt). Examples of the metal atom include alkali metals such as sodium and potassium, alkaline earth metals such as calcium, and transition metals such as iron. Examples of the organic amine salt include primary to quaternary amine salts such as methylamine salt, n-butylamine salt, monoethanolamine salt, dimethylamine salt, diethanolamine salt, morpholine salt, and trimethylamine salt. Only one (meth) acrylic acid (salt) may be used, or two or more types may be used.

  Examples of the dicarboxylic acid (salt) include maleic acid (salt), maleic anhydride (salt), fumaric acid (salt), itaconic acid (salt), itaconic anhydride (salt), and 2-methyleneglutaric acid (salt). Etc. The dicarboxylic acid (salt) is preferably maleic acid (salt). The salt here is a carboxyl group salt represented by COOM as described above, and M is a hydrogen atom, a metal atom, an ammonium group (composing an ammonium salt), or an organic amino group (organic amine). Salt). Examples of the metal atom include alkali metals such as sodium and potassium, alkaline earth metals such as calcium, and transition metals such as iron. Examples of the organic amine salt include primary to quaternary amine salts such as methylamine salt, n-butylamine salt, monoethanolamine salt, dimethylamine salt, diethanolamine salt, morpholine salt, and trimethylamine salt. Only one type of dicarboxylic acid (salt) may be used, or two or more types may be used.

  In addition to (meth) acrylic acid (salt) and dicarboxylic acid (salt), the monomer composition may contain other monomers. Examples of such other monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4 Hydroxyl group-containing alkyl (meth) acrylates such as hydroxybutyl (meth) acrylate and α-hydroxymethylethyl (meth) acrylate; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, ( Alkyl (meth) acrylates which are esters of alkyl groups having 1 to 18 carbon atoms of (meth) acrylic acid such as cyclohexyl (meth) acrylate and lauryl (meth) acrylate; dimethylaminoethyl (meth) acrylate or its quaternary Acrylic group-containing acrylate Amide group-containing monomers such as (meth) acrylamide, dimethylacrylamide and isopropylacrylamide; Vinyl esters such as vinyl acetate; Alkenes such as ethylene and propylene; Aromatic vinyl monomers such as styrene Maleimide derivatives such as maleimide, phenylmaleimide and cyclohexylmaleimide; nitrile group-containing vinyl monomers such as (meth) acrylonitrile; 2-acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid, (meth) allylsulfone Monomers having a sulfonic acid group such as acid, vinyl sulfonic acid, 2-hydroxy-3-allyloxy-1-propanesulfonic acid, 2-hydroxy-3-butenesulfonic acid, and salts thereof; vinylphosphonic acid, ( Phosphonic acids such as (meth) allylphosphonic acid Group-containing monomers; aldehyde group-containing vinyl monomers such as (meth) acrolein; alkyl vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether; polyalkylene glycol (meth) acrylate, monoalkoxy polyalkylene Polyalkylene glycol chain-containing monomers that are monomers having a structure in which 1 to 300 mol of alkylene oxide is added to unsaturated alcohol such as glycol (meth) acrylate, vinyl alcohol, (meth) allyl alcohol, and isoprenol; And monomers having other functional groups such as vinyl chloride, vinylidene chloride, allyl alcohol, vinyl pyrrolidone, and the like. These other monomers may be only one kind or two or more kinds.

  The content ratio of (meth) acrylic acid (salt) to dicarboxylic acid (salt) in the monomer composition is 95: 5 to 5:95, preferably 92: 8 to 20:80, in molar ratio. More preferably, it is 90: 10-50: 50. When the content ratio of (meth) acrylic acid (salt) and dicarboxylic acid (salt) in the monomer composition falls within the above range, (meth) acrylic acid (salt) -dicarboxylic acid (salt) of the present invention ) -Based copolymer can have a narrower molecular weight distribution and more excellent gelation resistance.

  When the monomer composition contains other monomers, the content ratio of the total of (meth) acrylic acid (salt) and dicarboxylic acid (salt) and the other monomers is a molar ratio, preferably 100. : 0 to 80:20, more preferably 100: 0 to 85:15, and still more preferably 100: 0 to 90:10. When the total content of (meth) acrylic acid (salt) and dicarboxylic acid (salt) in the monomer composition is within the above range, the (meth) acrylic of the present invention The acid (salt) -dicarboxylic acid (salt) copolymer may have a narrower molecular weight distribution and more excellent gelation resistance.

  The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention is preferably obtained through a polymerization step in the presence of a mercapto group-containing compound.

  Examples of the mercapto group-containing compound include thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiosuccinic acid, thiomalic acid, mercaptoacetic acid, 2-mercaptoethanol, sodium 3-mercapto-1-propanesulfonate, Examples include cysteine and salts thereof. Only one type of mercapto group-containing compound may be used, or two or more types may be used.

  The polymerization step in the presence of the mercapto group-containing compound is preferably a step in which the monomer composition is polymerized in the presence of hydrogen peroxide, a reducing agent, and a mercapto group-containing compound.

  Hydrogen peroxide can act mainly as a polymerization initiator in the polymerization step. For example, hydrogen peroxide in the form of an aqueous solution or in the form of a complex with another compound can be used. In producing the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention, it is preferable to use hydrogen peroxide in the form of an aqueous solution. By using hydrogen peroxide in the form of an aqueous solution, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) -based copolymer of the present invention can have a narrower molecular weight distribution and has a gel-resistant ability. Get better.

  The amount of hydrogen peroxide used is preferably 0.01 g to 5.0 g, more preferably 0.05 g to 4.0 g, and still more preferably 0.1 g, per 1 mol of the monomer composition. -3.0 g. By keeping the amount of hydrogen peroxide used within the above range, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can have a narrower molecular weight distribution and is resistant to gelation. Noh can get better.

  When hydrogen peroxide is used in the polymerization step in the presence of a mercapto group-containing compound, since hydrogen peroxide can mainly act as a polymerization initiator, the (meth) acrylic acid (salt) -dicarboxylic acid of the present invention is preferably used. One end of the main chain of the acid (salt) copolymer may be a hydroxyl group. In addition, when hydrogen peroxide is used in the polymerization step in the presence of a mercapto group-containing compound, the hydrogen peroxide does not contain a dispersibility inhibitor (for example, sulfate ion). ) The acrylic acid (salt) -dicarboxylic acid (salt) copolymer can be excellent in stability at low temperatures.

  In the polymerization step in the presence of the mercapto group-containing compound, other polymerization initiators may be used in combination with hydrogen peroxide. Examples of such other polymerization initiators include persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate; dimethyl-2,2′-azobis (2-methylpropionate), 2,2 ′. -Azobis (2-amidinopropane) hydrochloride, 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4- Dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (isobutyric acid) dimethyl, 4,4′-azobis (4-cyanovaleric acid) 2,2′-azobis (2-methylpropionamidine) dihydrochloride, 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] n hydrate, 2, '-Azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] disulfate dihydrate, 1 , 1′-azobis (cyclohexane-1-carbonitrile), etc .; organic peroxides such as benzoyl peroxide, lauroyl peroxide, peracetic acid, di-t-butyl peroxide, cumene hydroperoxide, etc. Is mentioned. Other polymerization initiators may be used alone or in combination of two or more.

  The amount of other polymerization initiator used is preferably 0 g to 5.0 g with respect to 1 mol of the monomer composition. By keeping the amount of other polymerization initiators used within the above range, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can have a narrower molecular weight distribution and is resistant to damage. The gelation ability can be more excellent.

  The reducing agent can act mainly as a decomposition catalyst for hydrogen peroxide in the polymerization step. Only one reducing agent may be used, or two or more reducing agents may be used. The reducing agent is preferably an organic compound reducing agent. By using the reducing agent of the organic compound, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can have a narrower molecular weight distribution and more excellent gelation resistance. obtain.

  Examples of the organic compound reducing agent include ascorbic acid, ascorbate, erythorbic acid, erythorbate, ascorbate, formic acid, formate, oxalic acid, oxalate, and hydroquinone. The “salt” here is a carboxyl group salt represented by COOM as described above, and M is a hydrogen atom, a metal atom, an ammonium group (constituting an ammonium salt), or an organic amino group (organic amine salt). Configuration). Examples of the metal atom include alkali metals such as sodium and potassium, alkaline earth metals such as calcium, and transition metals such as iron. Examples of the organic amine salt include primary to quaternary amine salts such as methylamine salt, n-butylamine salt, monoethanolamine salt, dimethylamine salt, diethanolamine salt, morpholine salt, and trimethylamine salt. Among these, the reducing agent is preferably ascorbic acid, ascorbate, erythorbic acid, or erythorbate, and more preferably ascorbic acid or ascorbate.

  The amount of the reducing agent to be used is preferably 0.01 g to 5.0 g, more preferably 0.05 g to 3.0 g, and still more preferably 0.1 g to 0.1 g relative to 1 mol of the monomer composition. 2.0 g. By keeping the amount of the reducing agent used within the above range, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can have a narrower molecular weight distribution and a gel resistance. Get better.

  As the reducing agent, an inorganic compound reducing agent may be used. Examples of the reducing agent for the inorganic compound include heavy metal ions (heavy metal salts). Examples of such heavy metal ions (heavy metal salts) include iron, cobalt, manganese, chromium, molybdenum, tungsten, copper, silver, gold, lead, platinum, iridium, osmium, palladium, rhodium, ruthenium, and the like; Sulfites such as sodium; bisulfites such as sodium bisulfite; dithionites such as sodium dithionite; hypophosphorous acids such as sodium hypophosphite; phosphites such as sodium phosphite; boron Compound; and the like.

  The mercapto group-containing compound can act mainly as a chain transfer agent in the polymerization step. Examples of the mercapto group-containing compound include thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiosuccinic acid, thiomalic acid, mercaptoacetic acid, 2-mercaptoethanol, sodium 3-mercapto-1-propanesulfonate, Examples include cysteine and salts thereof. Only one type of mercapto group-containing compound may be used, or two or more types may be used.

  The mercapto group-containing compound is preferably a mercapto group-containing compound having a carboxyl group. By using a mercapto group-containing compound having a carboxyl group as the mercapto group-containing compound, the molecular weight distribution of the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can be further narrowed. At the same time, the gelation resistance can be more excellent.

  When a mercapto group-containing compound having a carboxyl group is used as the mercapto group-containing compound, since the mercapto group-containing compound can mainly act as a chain transfer agent, the (meth) acrylic acid (salt) -dicarboxylic acid of the present invention is preferably used. One end of the main chain of the acid (salt) copolymer can be a carboxyl group via a sulfide bond.

  The amount of the mercapto group-containing compound used is preferably 0.1 g to 40 g, more preferably 0.3 g to 30 g, and still more preferably 0.5 g to 20 g, with respect to 1 mol of the monomer composition. is there. By keeping the amount of the mercapto group-containing compound used within the above range, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can be narrowed in molecular weight distribution and gel resistant. Ability to get better.

  In the polymerization step in the presence of the mercapto group-containing compound, other chain transfer agents may be used in combination with the mercapto group-containing compound. Examples of such other chain transfer agents include, for example, thiol chain transfer agents other than the mercapto group-containing compounds such as n-dodecyl mercaptan and octyl mercaptan; carbon tetrachloride, methylene chloride, bromoform, bromotrichloroethane, and the like. Halides; secondary alcohols such as isopropanol and glycerin; phosphorous acid, hypophosphorous acid, hypophosphites (such as sodium hypophosphite and potassium hypophosphite), hydrates thereof, etc. , Phosphoric acid (salts); bisulfite, dithionite, metabisulfite, salts thereof (sodium bisulfite, potassium bisulfite, sodium dithionite, potassium dithionite, sodium metabisulfite, meta Bisulfite (salts); and the like. Other chain transfer agents may be only one kind or two or more kinds.

  The amount of other chain transfer agent used is preferably 0 to 10 g with respect to 1 mol of the monomer composition. By keeping the amount of the other chain transfer agent used within the above range, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can have a narrower molecular weight distribution, The gelation ability can be more excellent.

  The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention preferably polymerizes a monomer composition containing (meth) acrylic acid (salt) and dicarboxylic acid (salt). Can be obtained. The polymerization may be performed in a polymerization solvent or without a solvent. The polymerization is preferably performed in a polymerization solvent. As a polymerization solvent, water, the mixed solvent of water and an organic solvent, and an organic solvent are mentioned, for example, Preferably it is water, the mixed solvent of water and an organic solvent. This is because, depending on the use of the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention, it may be better to reduce the presence of the organic solvent as much as possible.

  The polymerization concentration is preferably 10% to 70% by weight, more preferably 20% to 65% by weight, more preferably 25% to 60% by weight, based on the polymerization solution, as the solid content concentration. It is.

  The polymerization temperature is preferably 70 ° C or higher, more preferably 75 ° C to 110 ° C, and further preferably 80 ° C to 105 ° C. The polymerization temperature need not always be kept constant during the course of the polymerization reaction. For example, the polymerization is started from room temperature, the temperature is increased at an appropriate temperature increase time or rate, and then the set temperature is reached. You may make it hold | maintain. Further, during the polymerization reaction, the polymerization temperature may be changed (temperature increase or decrease) with time.

  The pressure in the system for the polymerization reaction may be normal pressure (atmospheric pressure), reduced pressure, or increased pressure. Preferably, it is under normal pressure (atmospheric pressure) and under pressure.

  The polymerization reaction system may be in an air atmosphere or an inert gas atmosphere.

  As a method for adding the monomer used for the polymerization, the entire amount used may be added to the reactor all at once, or a part or all of them may be added sequentially (preferably continuously) to the reactor. good. As a method for adding the monomer used for the polymerization, a part or all of the monomer is preferably added to the reactor sequentially (preferably continuously). This is because heat generation due to the polymerization reaction can be controlled, and the concentration of the monomer present in the reaction system during the polymerization can be controlled. Thus, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) of the present invention can be controlled. ) -Based copolymer can have a narrower molecular weight distribution and more excellent gelation resistance. The monomer may be added alone, may be added after being dissolved in a solvent such as water, or may be added by mixing with other raw materials.

  As a method for adding a polymerization initiator that preferably uses hydrogen peroxide, the entire amount used may be added to the reactor all at once, or a part or all of the reaction may be performed sequentially (preferably continuously). It may be added to the vessel. As a method for adding a polymerization initiator which preferably uses hydrogen peroxide, a part or all of the polymerization initiator is preferably added sequentially (preferably continuously) to the reactor. As a result, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can have a narrower molecular weight distribution and more excellent gelation resistance. The polymerization initiator that preferably contains hydrogen peroxide may be added alone, or may be added after being dissolved in a solvent such as water, or may be added by mixing with other raw materials. Also good. The polymerization initiator is preferably added after being dissolved in a solvent such as water.

  As a method for adding the monomer used for the polymerization, when part or all of the monomer is added sequentially (preferably continuously) to the reactor, it is preferable that the monomer is added at the same time as the monomer or the monomer. After the addition of the entire amount is completed, the addition of the polymerization initiator that preferably uses hydrogen peroxide is terminated, and more preferably between 0 minutes and 2 hours after the addition of the entire amount of monomer is completed. Then, the addition of the polymerization initiator is terminated. Such time is preferably 15 minutes to 1.5 hours. By adding the monomer used for the polymerization by such a method, the amount of the residual monomer can be effectively reduced.

  As a method for adding the reducing agent, the entire amount used may be added to the reactor all at once, or a part or all of the reducing agent may be added sequentially (preferably continuously) to the reactor. As a method for adding the reducing agent, a part or all of the reducing agent is preferably added sequentially (preferably continuously) to the reactor. As a result, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can have a narrower molecular weight distribution and more excellent gelation resistance. The reducing agent may be added alone, may be added after being dissolved in a solvent such as water, or may be added by mixing with other raw materials.

  As a method for adding a chain transfer agent which preferably contains a mercapto group-containing compound, the total amount used may be added to the reactor all at once, or a part or all of them may be added sequentially (preferably continuously). It may be added to the reactor. As a method for adding a chain transfer agent which preferably contains a mercapto group-containing compound, preferably a part or all of the chain transfer agent is added sequentially (preferably continuously) to the reactor. As a result, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can have a narrower molecular weight distribution and more excellent gelation resistance. The chain transfer agent that preferably contains the mercapto group-containing compound may be added alone, dissolved in a solvent such as water, or mixed with other raw materials and added. May be.

  As a method for adding a chain transfer agent that preferably contains a mercapto group-containing compound, when part or all of the chain transfer agent is added sequentially (preferably continuously) to the reactor, it is preferable to add the entire amount of monomer. At the same time or before the addition of the entire amount of monomer is completed, the addition of the chain transfer agent which preferably comprises the mercapto group-containing compound is terminated. By adding the monomer used for the polymerization by such a method, the amount of the residual monomer can be effectively reduced.

In the method for producing a (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention, a polyvalent metal ion may be added for the purpose of promoting polymerization, particularly in the polymerization step. . Examples of the polyvalent metal ions include iron ions (Fe ²⁺ , Fe ³⁺ ), vanadium ions (V ²⁺ , V ³⁺ , VO ²⁺ ), copper ions (Cu ²⁺ ), and the like. Among such polyvalent metal ions, iron ions (Fe ²⁺ , Fe ³⁺ ) are particularly preferable. Only one type of polyvalent metal ion may be used, or two or more types may be used.

Arbitrary appropriate supply forms can be employ | adopted as a supply form of a polyvalent metal ion. As such a supply form, the form using the metal and / or metal compound which ionize within a polymerization reaction system is mentioned, for example. For example, vanadium oxytrichloride, vanadium trichloride, vanadium oxalate, vanadium sulfate, vanadic anhydride, ammonium metavanadate, ammonium sulfate hypo-nosed Das _{((NH 4) 2 SO 4} · VSO 4 · 6H 2 O), ammonium sulfate nosed Das ((NH ₄ ) V (SO ₄ ) ₂ · 12H ₂ O), copper (II) acetate, copper (II) bromide, copper (II) acetyl acetate, cupric chloride, copper carbonate, copper (II) chloride , Copper (II) citrate, copper (II) formate, copper hydroxide (II), copper (II) oleate, copper maleate, copper phosphate, copper (II) sulfate, iron acetylacetonate, iron citrate Ammonium, ferric ammonium oxalate, ferrous ammonium sulfate, ferric ammonium sulfate, iron citrate, iron fumarate, iron maleate, ferrous lactate Water-soluble metal salts such as ferric nitrate, iron pentacarbonyl, ferric phosphate, and ferric pyrophosphate; metals such as vanadium pentoxide, copper (II) oxide, ferrous oxide, ferric oxide Oxides; metal sulfides such as copper (II) sulfide and iron sulfide; and the like.

  The polyvalent metal ions (the above metal compound and metal) are preferably charged in an amount of 80% by weight or more, more preferably the whole amount, in the initial stage. The polyvalent metal ion is preferably used in an amount of 1 ppm to 500 ppm, more preferably 3 to 400 ppm, based on the total amount of the reaction solution. When the amount of polyvalent metal ions used is less than the above range, the decomposition efficiency of hydrogen peroxide may be deteriorated. When the amount of the polyvalent metal ion used is larger than the above range, there is a possibility of causing coloring, and the effect of addition may be difficult to appear.

  In the method for producing a (meth) acrylic acid (salt) -dicarboxylic acid (salt) -based copolymer of the present invention, the copolymer produced in the polymerization step is an acid type or partially neutralized type in addition to the polymerization step. In some cases, a neutralization step may be included as necessary. In addition, if necessary, a mixing step for adding other components to the copolymer produced in the polymerization step, a purification step for removing or reducing a part of the components, and a solvent for the resulting copolymer solution A dilution step for increasing / decreasing the amount and a concentration / drying step may be included. That is, the method for producing a (meth) acrylic acid (salt) -dicarboxylic acid (salt) -based copolymer of the present invention is a single amount essentially containing (meth) acrylic acid (salt) and the dicarboxylic acid (salt). Including the step of polymerizing the body in the presence of a mercapto group-containing compound, and if necessary, including other steps (for example, the above neutralization step, mixing step, purification step, dilution step, concentration / drying step, etc.) May be.

  In the method for producing a (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention, the dropping time of each component dropped during polymerization in the polymerization step is preferably 30 minutes to 420 minutes. More preferably, it is 60 minutes to 360 minutes. The dropping time of each component dropped during the polymerization in the polymerization step may be different depending on the dropping time of each component. Arbitrary appropriate speed | velocity | rates can be employ | adopted for the dripping speed | rate of each component in the range which does not impair the effect of this invention. For example, the dropping speed may be constant from the start to the end of dropping, and the dropping speed may be changed as necessary.

  In the method for producing a (meth) acrylic acid (salt) -dicarboxylic acid (salt) -based copolymer of the present invention, in the polymerization step, a part or all of the monomers are reacted in a reaction vessel (reaction solution) before the start of polymerization. It is also possible to add to (initial charge).

  In the method for producing a (meth) acrylic acid (salt) -dicarboxylic acid (salt) -based copolymer of the present invention, the residual monomer can be reduced in the polymerization step, so that the entire amount of the dicarboxylic acid (salt) is polymerized. It is preferable to add to the reaction vessel (reaction solution) before the start. However, part or all of the dicarboxylic acid (salt) may be added after the start of polymerization.

  In this specification, “before the start of polymerization” and “after the start of polymerization” mean before the start of polymerization and after the start of polymerization, respectively. In the present specification, the “polymerization start point” means a point in time when a part or all of the polymerization initiator and a part or all of the monomer are first added to the reaction vessel (reaction liquid). .

≪Use of (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer≫
The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can be used for any appropriate application. Examples of such applications include flocculants, thickeners, pressure-sensitive adhesives, adhesives, surface coating agents, inorganic fiber crosslinking agents, organic fiber crosslinking agents, and crosslinkable compositions. Includes pigment dispersants, detergent builders, heavy metal scavengers, scale inhibitors, metal surface treatment agents, dyeing aids, dye fixing agents, foam stabilizers, emulsion stabilizers, ink dye dispersants, aqueous ink stabilizers, paints Pigment Dispersant, Paint Thickener, Pressure Sensitive Adhesive, Paper Adhesive, Stick Glue, Medical Adhesive, Patch Adhesive, Cosmetic Pack Adhesive, Resin Filler Dispersant, Resin Hydrophilizer , Recording paper coating agent, inkjet paper surface treatment agent, photosensitive resin dispersant, antistatic agent, moisturizer, fertilizer binder, pharmaceutical tablet binder, resin compatibilizer, photographic additive, cosmetic preparation Additives, hairdressing aids , Hair spray additives, like sunscreen composition additives.

≪Detergent composition≫
The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can be preferably applied to a detergent composition. That is, the detergent composition of the present invention contains the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention.

  The detergent composition of the present invention preferably contains the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention and a surfactant.

  In the detergent composition of the present invention, any appropriate blending amount can be adopted as the blending amount of the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention and the surfactant. . As such a blending amount, for example, from the viewpoints of capturing magnesium ions in tap water, dispersing clay, preventing deposition of magnesium hydroxide scale, etc., the (meth) acrylic acid ( Salt) -dicarboxylic acid (salt) copolymer is preferably 1% by weight to 20% by weight, more preferably 2% by weight to 18% by weight, and the surfactant is preferably 5% by weight to 60% by weight, more preferably 10% by weight to 55% by weight.

  The detergent composition of the present invention is a known polymer such as a glyoxylic acid-based polymer (salt), a polyaspartic acid-based polymer (salt), etc., as long as its performance and effects are not impaired. A polymer builder may be included.

  As the surfactant, at least one selected from the group consisting of an anionic surfactant, a nonionic surfactant, an amphoteric surfactant, and a cationic surfactant can be preferably used.

  Any appropriate anionic surfactant can be adopted as the anionic surfactant. Examples of such anionic surfactants include alkylbenzene sulfonates, alkyl or alkenyl ether sulfates, alkyl or alkenyl sulfates, α-olefin sulfonates, α-sulfo fatty acid or ester salts, alkane sulfonates, Examples thereof include saturated or unsaturated fatty acid salts, alkyl or alkenyl ether carboxylates, amino acid type surfactants, N-acyl amino acid type surfactants, alkyl or alkenyl phosphate esters or salts thereof. Only one type of anionic surfactant may be used, or two or more types may be used.

  Any appropriate nonionic surfactant can be adopted as the nonionic surfactant. Examples of such nonionic surfactants include polyoxyalkylene alkyl or alkenyl ether, polyoxyethylene alkyl phenyl ether, higher fatty acid alkanolamide or an alkylene oxide adduct thereof, sucrose fatty acid ester, alkyl glycoxide, fatty acid glycerin monoester. Examples thereof include esters and alkylamine oxides. Only one nonionic surfactant may be used, or two or more nonionic surfactants may be used.

  Any appropriate amphoteric surfactant can be adopted as the amphoteric surfactant. Examples of such amphoteric surfactants include carboxy type or sulfobetaine type amphoteric surfactants. Only one amphoteric surfactant may be used, or two or more amphoteric surfactants may be used.

  Any appropriate cationic surfactant can be adopted as the cationic surfactant. Examples of such cationic surfactants include quaternary ammonium salts. Only one type of cationic surfactant may be used, or two or more types may be used.

  In order to improve the detergency, the detergent composition of the present invention may further contain an enzyme as necessary. Examples of such an enzyme include protease, lipase, cellulase and the like. Among such enzymes, protease, alkaline lipase, and lucal cellulase are preferable because they are highly active in an alkaline cleaning solution. The compounding amount of the enzyme is preferably 0.01% by weight to 1% by weight with respect to the total amount of the detergent composition. If the amount of the enzyme is out of this range, the balance with the surfactant may be lost, and the cleaning power may not be improved.

  If necessary, the detergent composition of the present invention may further contain components commonly used in known detergent compositions such as known alkali builders, chelate builders, anti-redeposition agents, fluorescent agents, bleaching agents, and fragrances. May be. Moreover, you may mix | blend a zeolite with the detergent composition of this invention at the point which can improve a cleaning power significantly. As the alkali builder, for example, silicate, carbonate, sulfate and the like can be used. Examples of the chelate builder include HIDS (hydroxyiminodisuccinate), IDS (iminodisuccinate), CMOS (carboxymethyloxysuccinate), diglycolic acid, oxycarboxylate, EDTA (ethylenediaminetetraacetic acid), DTPA (Diethylenetriaminehexaacetic acid), citric acid, ss-EDDS (ss-ethylenediamine disuccinate), MGDA (methylglycine triacetate), GLDA (L-glutamic acid diacetate) and the like can be used. Further, for the purpose of improving detergency, a substance such as an EO (ethylene oxide) addition product to polyethyleneimine may be used in combination as a soil releasing agent.

≪Water treatment agent≫
The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can be used as a water treatment agent. That is, the water treatment agent of the present invention includes the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention. Such water treatment agents may contain polymerized phosphates, phosphonates, anticorrosives, slime control agents, chelating agents, and the like as other compounding agents as necessary.

  The water treatment agent of the present invention is useful for scale prevention in a cooling water circulation system, a boiler water circulation system, a seawater desalination apparatus, a reverse osmosis membrane treatment apparatus, a pulp digester, a black liquor concentration tank, and the like. Moreover, the water treatment agent of the present invention may contain any appropriate water-soluble polymer as long as it does not affect the performance and effects.

  In the water treatment agent of the present invention, as the blending amount of the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention and water or other additives, any appropriate blending amount is used. Can be adopted. As such a blending amount, for example, from the viewpoint of suppressing the scale of calcium carbonate and iron hydroxide in the water in the cooling water circulation system, the (meth) acrylic acid (salt)- The dicarboxylic acid (salt) copolymer is preferably 0.1% by weight to 100% by weight, and more preferably 1% by weight to 70% by weight.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples at all. Unless otherwise specified, parts and% in the examples are based on weight.

<Measurement of weight average molecular weight and number average molecular weight>
(Examples 1 to 3 and Comparative Example 1)
Equipment: Tosoh high-speed GPC equipment (HLC-8320GPC)
Detector: RI
Column: Tosoh TSK-GEL G-4000PW, G-3000PW
Column temperature: 40 ° C
Flow rate: 0.5 ml / min
Calibration curve: POLYACRYLIC ACID STANDARD made by Soka Science Co., Ltd.
Eluent: 0.08M phosphoric acid aqueous solution (for Examples 4 to 6 and Comparative Example 2)
Equipment: Tosoh high-speed GPC equipment (HLC-8320GPC)
Detector: RI
Column: SHODEX Asahipak GF-310-HQ, GF-710-HQ, GF-1G 7B manufactured by Showa Denko
Column temperature: 40 ° C
Flow rate: 0.5 ml / min
Calibration curve: POLYACRYLIC ACID STANDARD made by Soka Science Co., Ltd.
Eluent: 0.1N sodium acetate aqueous solution

<Measurement of residual monomer>
Apparatus: Waters Alliance e-2695 system Detector: UV detector (200 nm)
Column: Showa Denko SHODEX RSpak DE-413L
Column temperature: 40 ° C
Flow rate: 1.0 ml / min
Eluent: 0.1% phosphoric acid aqueous solution

<Measurement of gelation resistance>
(1) Glycine: 67.6 g, sodium chloride 52.6 g, 1 mol / L NaOH aqueous solution: 60 ml of ion-exchanged water was added to 600 g to prepare a glycine buffer.
(2) Glycine buffer solution: Pure was added to 54 g to make 1000 g.
(3) A 1% sample aqueous solution (copolymer aqueous solution to be measured) in terms of solid content was prepared.
(4) To a 100 ml beaker, 80 g of the aqueous solution of (2) and 2.5 g of the aqueous solution of (3) were added.
(5) 1 mol / L calcium chloride aqueous solution was dripped at the aqueous solution of (4) with the automatic titrator. The turbidity of the aqueous solution was measured with a photoelectrode, and the titration amount at which the liquid became turbid was determined.
(6) From the titration amount in which turbidity occurred, the gelation ability was determined by the following formula.
(7) Gelation resistance = [[titrated amount (ml) × 0.1] / [2.5 × 0.01]] × 100

<Measurement of solid content>
In an oven heated to 130 ° C., the copolymer composition (1.0 g of the copolymer composition plus 1.0 g of water) was left to dry for 1 hour. From the weight change before and after drying, the solid content (%) and the volatile component (%) were calculated.

[Example 1]
To a SUS reactor equipped with a thermometer, a stirrer, and a reflux condenser, maleic anhydride (abbreviated as MAN): 43.6 g (0.44 mol), 48% NaOH aqueous solution: 16.7 g (0.20 mol), Pure water: 116.9 g was charged and heated to 100 ° C.
Next, 80% acrylic acid aqueous solution (abbreviated as 80% AA): 360 g (4.0 mol) in 180 minutes, 30% 3-mercaptopropionic acid aqueous solution (abbreviated as 30% MPA): 66.7 g (0 .19 mol) in 180 minutes, 5% hydrogen peroxide aqueous solution (abbreviated as 5% H ₂ O ₂ ): 44.4 g (0.0147 mol) and 2% L-ascorbic acid aqueous solution (abbreviated as 2% L-As) Yes): 44.4 g (0.0050 mol) was added dropwise continuously over 240 minutes.
After completion of dropwise addition of 5% H ₂ O ₂ and 2% L-As, the mixture was stirred for 30 minutes, 48% NaOH aqueous solution: 389.5 g and pure water: 139.2 g were added separately, and (meth) acrylic acid (salt) A dicarboxylic acid (salt) copolymer (1) was obtained.
The amount of residual monomer was 380.0 ppm for residual acrylic acid and 80 ppm for residual maleic acid, and the reaction proceeded almost completely. The solid content was 40.5%.
The results are shown in Table 1.

[Example 2]
In a SUS reactor equipped with a thermometer, a stirrer, and a reflux condenser, maleic anhydride (abbreviated as MAN): 43.6 g (0.44 mol), 48% NaOH aqueous solution: 20.7 g (0.25 mol), Pure water: 153.4 g was charged and heated to 90 ° C.
Next, 80% acrylic acid aqueous solution (abbreviated as 80% AA): 360 g (4.0 mol) in 180 minutes, 30% 3-mercaptopropionic acid aqueous solution (abbreviated as 30% MPA): 103.7 g (0 .29 mol) in 180 minutes, 5% aqueous hydrogen peroxide solution (abbreviated as 5% H ₂ O ₂ ): 44.4 g (0.0147 mol) and 2% L-ascorbic acid aqueous solution (abbreviated as 2% L-As) Yes): 44.4 g (0.0050 mol) was added dropwise continuously over 240 minutes.
After completion of dropwise addition of 5% H ₂ O ₂ and 2% L-As, the mixture was stirred for 30 minutes, 48% NaOH aqueous solution: 346.3 g and pure water: 87.8 g were added separately, and (meth) acrylic acid (salt) A dicarboxylic acid (salt) copolymer (2) was obtained.
The amount of residual monomer was 900.0 ppm for residual acrylic acid and 200 ppm for residual maleic acid, and the reaction proceeded almost completely. The solid content was 41.3%.
The results are shown in Table 1.

Example 3
In a SUS reactor equipped with a thermometer, a stirrer and a reflux condenser, maleic anhydride (abbreviated as MAN): 43.6 g (0.44 mol), 48% NaOH aqueous solution: 10.4 g (0.12 mol), Pure water: 153.4 g was charged and heated to 90 ° C.
Next, 80% acrylic acid aqueous solution (abbreviated as 80% AA): 360 g (4.0 mol) in 180 minutes, 30% 3-mercaptopropionic acid aqueous solution (abbreviated as 30% MPA): 212.3 g (0 .64 mol) in 180 minutes, 5% hydrogen peroxide aqueous solution (abbreviated as 5% H ₂ O ₂ ): 44.4 g (0.0147 mol) and 2% L-ascorbic acid aqueous solution (abbreviated as 2% L-As) Yes): 44.4 g (0.0050 mol) was added dropwise continuously over 240 minutes.
After completion of dropwise addition of 5% H ₂ O ₂ and 2% L-As, the mixture was stirred for 30 minutes, 48% NaOH aqueous solution: 401.3 g and pure water: 54.6 g were added separately, and (meth) acrylic acid (salt) A dicarboxylic acid (salt) copolymer (3) was obtained.
The amount of residual monomer was 460.0 ppm for residual acrylic acid and less than 1 ppm for residual maleic acid, and the reaction proceeded almost completely. The solid content was 41.0%.
The results are shown in Table 1.

[Comparative Example 1]
In a SUS reactor equipped with a thermometer, a stirrer, and a reflux condenser, maleic anhydride (abbreviated as MAN): 131.3 g (1.34 mol), 48% NaOH aqueous solution: 62.5 g (0.75 mol), Pure water: 461.5 g was charged and heated to 90 ° C.
Next, 80% acrylic acid aqueous solution (abbreviated as 80% AA): 1080 g (12 mol) in 180 minutes, 15% sodium persulfate aqueous solution (abbreviated as 15% NaPS): 266.8 g (0.0095 mol) In 180 minutes, 35% sodium bisulfite aqueous solution (abbreviated as 35% SBS): 381.1 g (1.28 mol) was added dropwise continuously in 170 minutes.
After completion of the dropwise addition of 15% NaPS, the mixture was stirred for 30 minutes, and a 48% aqueous NaOH solution: 116.7 g was added to obtain a (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer (C1).
The amount of residual monomer was 8 ppm for residual acrylic acid and less than 1 ppm for residual maleic acid, and the reaction proceeded almost completely. The solid content was 44.3%.
The results are shown in Table 1.

Example 4
In a SUS reactor equipped with a thermometer, a stirrer and a reflux condenser, maleic anhydride (abbreviated as MAN): 98 g (1.00 mol), 48% NaOH aqueous solution: 166.7 g (2.00 mol), pure water : 135.5 g was charged and the temperature was raised to 100 ° C.
Next, 80% acrylic acid aqueous solution (abbreviated as 80% AA): 338.3 g (3.8 mol) in 180 minutes, 48% NaOH aqueous solution: 213.5 g (2.562 mol) in 180 minutes, 30% 3-mercaptopropionic acid aqueous solution (abbreviated as 30% MPA): 31.7 g (0.09 mol) in 180 minutes, 5% hydrogen peroxide aqueous solution (abbreviated as 5% H ₂ O ₂ ): 57.1 g ( 0.084 mol) and 2% L-ascorbic acid aqueous solution (abbreviated as 2% L-As): 47.6 g (0.0050 mol) was added dropwise continuously over 240 minutes.
After completion of dropwise addition of 5% H ₂ O ₂ and 2% L-As, the mixture was stirred for 30 minutes, 48% NaOH aqueous solution: 48.7 g and pure water: 340.8 g were added separately, and (meth) acrylic acid (salt) A dicarboxylic acid (salt) copolymer (4) was obtained.
The amount of residual monomer was 340.0 ppm for residual acrylic acid and 740 ppm for residual maleic acid, and the reaction proceeded almost completely. The solid content was 37.6%.
The results are shown in Table 1.

Example 5
In a SUS reactor equipped with a thermometer, a stirrer and a reflux condenser, maleic anhydride (abbreviated as MAN): 98 g (1.00 mol), 48% NaOH aqueous solution: 166.7 g (2.00 mol), pure water : 135.5 g was charged and the temperature was raised to 100 ° C.
Next, 80% acrylic acid aqueous solution (abbreviated as 80% AA): 338.3 g (3.8 mol) in 180 minutes, 48% NaOH aqueous solution: 212.3 g (2.562 mol) in 180 minutes, 30% 3-mercaptopropionic acid aqueous solution (abbreviated as 30% MPA): 25.4 g (0.07 mol) in 180 minutes, 5% hydrogen peroxide aqueous solution (abbreviated as 5% H ₂ O ₂ ): 47.6 g ( 0.070 mol) and 2% L-ascorbic acid aqueous solution (abbreviated as 2% L-As): 47.6 g (0.0050 mol) was added dropwise continuously over 240 minutes.
After completion of dropwise addition of 5% H ₂ O ₂ and 2% L-As, the mixture was stirred for 30 minutes, 48% NaOH aqueous solution: 48.7 g and pure water: 340.8 g were added separately, and (meth) acrylic acid (salt) A dicarboxylic acid (salt) copolymer (5) was obtained.
The amount of residual monomer was 310.0 ppm for residual acrylic acid and 740 ppm for residual maleic acid, and the reaction proceeded almost completely. The solid content was 36.4%.
The results are shown in Table 1.

Example 6
In a SUS reactor equipped with a thermometer, a stirrer and a reflux condenser, maleic anhydride (abbreviated as MAN): 98 g (1.00 mol), 48% NaOH aqueous solution: 166.7 g (2.00 mol), pure water : 135.5 g was charged and the temperature was raised to 100 ° C.
Next, 80% acrylic acid aqueous solution (abbreviated as 80% AA): 338.3 g (3.8 mol) in 180 minutes, 48% NaOH aqueous solution: 212.3 g (2.562 mol) in 180 minutes, 30% 3-mercaptopropionic acid aqueous solution (abbreviated as 30% MPA): 19 g (0.04 mol) in 180 minutes, 5% hydrogen peroxide aqueous solution (abbreviated as 5% H ₂ O ₂ ): 48.7 g (0. 070 mol) and 2% L-ascorbic acid aqueous solution (abbreviated as 2% L-As): 47.6 g (0.0050 mol) was added dropwise continuously over 240 minutes.
After completion of dropwise addition of 5% H ₂ O ₂ and 2% L-As, the mixture was stirred for 30 minutes, 48% NaOH aqueous solution: 48.7 g and pure water: 340.8 g were added separately, and (meth) acrylic acid (salt) A dicarboxylic acid (salt) copolymer (6) was obtained.
The amount of residual monomer was 220.0 ppm for residual acrylic acid and 200 ppm for residual maleic acid, and the reaction proceeded almost completely. The solid content was 36.4%.
The results are shown in Table 1.

[Comparative Example 2]
In a SUS reactor equipped with a thermometer, a stirrer and a reflux condenser, maleic anhydride (abbreviated as MAN): 98 g (1.00 mol), 48% NaOH aqueous solution: 166.7 g (2.00 mol), pure water : 135.5 g was charged and the temperature was raised to 100 ° C.
Next, 80% acrylic acid aqueous solution (abbreviated as 80% AA): 338.3 g (3.8 mol) over 180 minutes, 48% NaOH aqueous solution: 208.3 g (2.5 mol) over 180 minutes, 35% Hydrogen peroxide aqueous solution (abbreviated as 35% H ₂ O ₂ ): 8.2 g (0.084 mol) in 120 minutes after 60 minutes, 15% sodium persulfate aqueous solution (abbreviated as 15% NaPS): 64 g ( 0.04 mol) was added dropwise separately over 190 minutes.
After completion of the dropwise addition of 15% NaPS, the mixture was stirred for 30 minutes, and 48% NaOH aqueous solution: 48.3 g was added to obtain a (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer (C2).
The amount of residual monomer was 150.0 ppm for residual acrylic acid and 400 ppm for residual maleic acid, and the reaction proceeded almost completely. The solid content was 40.0%.
The results are shown in Table 1.

  As shown in Table 1, the molecular weight distribution of the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention is narrowed. For example, when the weight average molecular weights Mw are compared at the same level, the molecular weight distribution of Example 3 is narrower than that of Comparative Example 1, and also compared with that of Comparative Example 2, Examples 4-6. The molecular weight distribution is narrowed. Furthermore, as shown in Table 1, the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention is excellent in gelation resistance. For example, compared with the comparative example 1, Examples 1-3 are excellent in gelation resistance, and compared with the comparative example 2, Examples 1-3 are excellent in gelation resistance.

The (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer of the present invention can be used for any appropriate application. Examples of such applications include flocculants, thickeners, pressure-sensitive adhesives, adhesives, surface coating agents, inorganic fiber crosslinking agents, organic fiber crosslinking agents, and crosslinkable compositions. Includes pigment dispersants, detergent builders, heavy metal scavengers, scale inhibitors, metal surface treatment agents, dyeing aids, dye fixing agents, foam stabilizers, emulsion stabilizers, ink dye dispersants, aqueous ink stabilizers, paints Pigment Dispersant, Paint Thickener, Pressure Sensitive Adhesive, Paper Adhesive, Stick Glue, Medical Adhesive, Patch Adhesive, Cosmetic Pack Adhesive, Resin Filler Dispersant, Resin Hydrophilizer , Recording paper coating agent, inkjet paper surface treatment agent, photosensitive resin dispersant, antistatic agent, moisturizer, fertilizer binder, pharmaceutical tablet binder, resin compatibilizer, photographic additive, cosmetic preparation Additives, hairdressing aids , Hair spray additives, like sunscreen composition additives.

Claims (5)

A (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer comprising a structural unit derived from (meth) acrylic acid (salt) and a structural unit derived from dicarboxylic acid (salt),
Having a sulfide bond in the structure of the copolymer;
The molar ratio of the structural unit derived from the (meth) acrylic acid (salt) and the structural unit derived from the dicarboxylic acid (salt) constituting the copolymer is in the range of 95: 5 to 5:95,
The weight average molecular weight is 500-200000,
(Meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer. A (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer comprising a structural unit derived from (meth) acrylic acid (salt) and a structural unit derived from dicarboxylic acid (salt),
Obtained through a polymerization step in the presence of a mercapto group-containing compound,
The molar ratio of the structural unit derived from the (meth) acrylic acid (salt) and the structural unit derived from the dicarboxylic acid (salt) constituting the copolymer is in the range of 95: 5 to 5:95,
The weight average molecular weight is 500-200000,
(Meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer. A method for producing a (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer according to claim 1 or 2,
Including a step of polymerizing a monomer essentially containing the (meth) acrylic acid (salt) and the dicarboxylic acid (salt) in the presence of a mercapto group-containing compound,
A method for producing a (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer.   A detergent composition comprising the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer according to claim 1 or 2. A water treatment agent comprising the (meth) acrylic acid (salt) -dicarboxylic acid (salt) copolymer according to claim 1.