Polycarboxylic acid-based copolymer
Patent Information
- Application Number
- JP2025512422
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Filing Date
- 2025-07-17
- Publication Date
- 2025-09-30
Smart Images
Figure 2024209783000001 
Figure 2024209783000002 
Figure 2024209783000003
Abstract
Description
Polycarboxylic acid copolymer
[0001] The present invention relates to a polycarboxylic acid copolymer, and more particularly to a polycarboxylic acid copolymer useful as a water treatment agent or the like.
[0002] Polycarboxylic acid copolymers are water-soluble polymers and are widely used in various fields, among which low-molecular-weight copolymers have excellent chelating ability and dispersing performance and are suitably used in various applications such as dispersants for inorganic pigments, metal ions, etc., detergent builders, water treatment agents such as anticorrosives and scale inhibitors, etc. For example, in cooling water systems, boiler water systems, seawater desalination plants, pulp dissolving vessels, black liquor concentrating vessels, etc., deposits (scale) such as calcium carbonate, zinc phosphate, calcium phosphate, zinc hydroxide, magnesium silicate, etc. adhere to the inner walls, which can cause operational problems such as reduced thermal efficiency and localized corrosion, and polycarboxylic acid copolymers are used as anticorrosives and scale inhibitors to inhibit or remove such scale.
[0003] The main components of silica scale include silicates such as magnesium silicate and silica polymers. Patent Document 1 discloses a silica scale inhibitor containing a (meth)acrylic acid copolymer, which is a copolymer containing structural units derived from (meth)acrylic acid (salt) and structural units derived from a sulfonic acid (salt) group-containing monomer, wherein the structural units derived from the sulfonic acid (salt) group-containing monomer account for 11 mol% or more of the total monomer-derived structures (100 mol%), the copolymer has a sulfonic acid (salt) group at at least one main chain end, and has a weight-average molecular weight of 20,000 or more. Patent Document 2 discloses a silica scale inhibitor comprising polyethylene glycol and an oxidizing agent.
[0004] Furthermore, as a technology for suppressing precipitation of silica polymers, Patent Document 3 discloses a silica scale inhibitor containing a (meth)acrylic acid-based copolymer, which is a copolymer containing structural units derived from (meth)acrylic acid (salt) and structural units derived from a sulfonic acid (salt) group-containing monomer, characterized in that the structural units derived from the sulfonic acid (salt) group-containing monomer account for 11 mol% or more of 100 mol% of all monomer-derived structures, and the weight-average molecular weight is 9200 or less. Patent Document 4 discloses a water-soluble copolymer characterized by being obtained by polymerizing 45 to 95% by weight of a polyalkylene oxide group-containing monomer and 55 to 5% by weight of a sulfonic acid group-containing monomer.
[0005] JP 2022-114909 A JP 2022-114873 A JP 2022-114873 A JP 2004-027060 A
[0006] In cooling facilities in factories and the like, a portion of hot water that has come into contact with a high-temperature object is vaporized in a cooling tower, and the cooled water is recirculated. The circulating water used in cooling facilities contains trace amounts of silica, and by recirculating the vaporized and cooled water, the silica is concentrated, making scale more likely to precipitate. This silica scale deposition causes a decrease in heat exchange capacity. Suppressing the deposition of both magnesium silicate and silica polymers, which are the main components of silica scale, can effectively suppress silica scale deposition when cooling facilities and the like are operated under conditions where the silica content in the circulating water is concentrated. Therefore, there has been a need for a technology to suppress the deposition of both magnesium silicate and silica polymers. As described above, various polymers used in water treatment agents have been disclosed in the past, but the conventional polymers have been insufficient in terms of suppressing the deposition of both magnesium silicate and silica polymers.
[0007] The present invention has been made in view of the above-mentioned current situation, and an object of the present invention is to provide a copolymer capable of suppressing the precipitation of both magnesium silicate and silica polymer.
[0008] The present inventors have conducted extensive research into polycarboxylic acid copolymers and have found that copolymers having structural units derived from unsaturated carboxylic acid monomers, sulfonic acid group-containing monomers, polyalkylene glycol monomers, and hydrophobic monomers can suppress the precipitation of both magnesium silicate and silica polymers. This has led to the realization that the above-mentioned problems can be solved in an excellent manner, and has led to the present invention.
[0009] The present invention includes the following polycarboxylic acid copolymers, etc.: [1] A copolymer comprising a structural unit (a) derived from an unsaturated carboxylic acid monomer (A), a structural unit (b) derived from a sulfonic acid group-containing monomer (B), and a copolymer represented by the following formula (1): (In the formula, R １ , R ２ and R ３ are the same or different and represent a hydrogen atom or a methyl group. ４ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. (R ５ and (O) are the same or different and represent an oxyalkylene group having 2 to 18 carbon atoms. n represents the average number of moles of oxyalkylene groups added and is a number from 1 to 300. x1 represents a number from 0 to 4. y1 represents 0 or 1. A polycarboxylic acid copolymer having a structural unit (c) derived from a polyalkylene glycol monomer (C) represented by the formula (I) and a structural unit (d) derived from a hydrophobic monomer (D). [2] The polycarboxylic acid copolymer according to the above item [1], having a weight average molecular weight of 10,000 to 200,000. [3] The polycarboxylic acid copolymer according to the above item [1] or [2], wherein the hydrophobic monomer (D) is a monomer represented by the following formula (2): (In the formula, R ６ , R ７ and R ８ are the same or different and represent a hydrogen atom or a methyl group. x2 represents a number from 0 to 4. y2 represents 0 or 1. Z represents a hydrocarbon group having 4 to 18 carbon atoms or a group represented by the following formula (3): (In the formula, X １ , Y １ represents a hydroxyl group or a group represented by the following formula (4) or (5), and X １ , Y １One of the groups represents a hydroxyl group, and the other is a group represented by the following formula (4) or (5): (In the formula, R ９ are the same or different and represent an alkylene group having 2 to 4 carbon atoms. m is an oxyalkylene group (—O—R ９ -) and represents a number from 0 to 5. １０ represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms. １１ , R １２ are the same or different and represent an alkyl group having 1 to 18 carbon atoms. １１ , R １２ The total number of carbon atoms in the structural units (a) is 4 or more. [4] The polycarboxylic acid copolymer according to any one of [1] to [3] above, wherein the content of the structural unit (a) is 15 to 95% by mass, based on 100% by mass of all structural units. [5] The polycarboxylic acid copolymer according to any one of [1] to [4] above, wherein the content of the structural unit (b) is 0.1 to 40% by mass, based on 100% by mass of all structural units. [6] The polycarboxylic acid copolymer according to any one of [1] to [5] above, wherein the content of the structural unit (c) is 10 to 70% by mass, based on 100% by mass of all structural units. [7] The polycarboxylic acid copolymer according to any one of [1] to [6] above, wherein the content of the structural unit (d) is 0.1 to 20% by mass, based on 100% by mass of all structural units. [8] The polycarboxylic acid copolymer according to any one of [1] to [7] above, wherein the polycarboxylic acid copolymer may have a structural unit (e) derived from a monomer (E) other than the unsaturated carboxylic acid monomer (A), the sulfonic acid group-containing monomer (B), the polyalkylene glycol monomer (C), and the hydrophobic monomer (D), and the proportion of the structural unit (e) is 0 to 30 mass% relative to 100 mass% of all structural units. [9] A water treatment agent containing a polycarboxylic acid copolymer, wherein the polycarboxylic acid copolymer comprises a structural unit (a) derived from the unsaturated carboxylic acid monomer (A), a structural unit (b) derived from the sulfonic acid group-containing monomer (B), and a structural unit represented by the following formula (1); (In the formula, R １ , R ２ and R ３ are the same or different and represent a hydrogen atom or a methyl group. ４represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. (R ５ and (C) represents a structural unit (d) derived from a hydrophobic monomer (D).
[0010] The polycarboxylic acid copolymer of the present invention has the above-mentioned constitution and can inhibit the precipitation of both magnesium silicate and silica polymer, and therefore can be suitably used as a water treatment agent or the like.
[0011] Preferred embodiments of the present invention will be specifically described below, but the present invention is not limited to the following description and can be appropriately modified and applied within the scope of the present invention. Note that a combination of two or more of the individual preferred embodiments of the present invention described below also falls within the scope of the present invention.
[0012] [Polycarboxylic Acid Copolymer] The polycarboxylic acid copolymer of the present invention (hereinafter also referred to as the copolymer of the present invention) has a structural unit (a) derived from an unsaturated carboxylic acid monomer (A), a structural unit (b) derived from a sulfonic acid group-containing monomer (B), a structural unit (c) derived from a polyalkylene glycol monomer (C) represented by the following formula (1), and a structural unit (d) derived from a hydrophobic monomer (D). In the present invention, it is believed that the presence of a carboxyl group or a salt thereof, a polyoxyalkylene group, and a hydrophobic group in the polycarboxylic acid copolymer mainly contributes to the inhibition of silicate precipitation, and the presence of a polyoxyalkylene group mainly contributes to the inhibition of silica polymer precipitation. The presence of a carboxyl group or a salt thereof, and a sulfonic acid group or a salt thereof in the polycarboxylic acid copolymer improves the solubility and hardness resistance of the polymer, and therefore it is believed that the silicate precipitation inhibition effect and the silica polymer precipitation inhibition effect can be fully exerted. In the present invention, the structural unit derived from a monomer means a structure (-C-C-) in which a carbon-carbon double bond (C=C) of a monomer is replaced with a single bond to form a bond with adjacent carbon atoms. In the present invention, the structural unit derived from a monomer is not limited to one formed by polymerizing a monomer, and may be one formed by a reaction other than a polymerization reaction.
[0013] In the copolymer, the content of the structural unit (a) is not particularly limited, but is preferably 15 to 95% by mass, more preferably 30 to 80% by mass, even more preferably 40 to 70% by mass, and particularly preferably 50 to 60% by mass, relative to 100% by mass of all structural units.
[0014] In the copolymer, the content of the structural unit (b) is not particularly limited, but is preferably 0.1 to 40% by mass, more preferably 0.5 to 30% by mass, even more preferably 1 to 20% by mass, still more preferably 2 to 15% by mass, and particularly preferably 3 to 10% by mass, relative to 100% by mass of all structural units.
[0015] In the copolymer, the content of the structural unit (c) is not particularly limited, but is preferably 5 to 80% by mass, more preferably 10 to 70% by mass, even more preferably 20 to 60% by mass, and particularly preferably 30 to 50% by mass, relative to 100% by mass of all structural units.
[0016] In the copolymer, the content of the structural unit (d) is not particularly limited, but is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, even more preferably 2 to 12% by mass, and particularly preferably 5 to 9% by mass, relative to 100% by mass of all structural units.
[0017] When the copolymer has the structural units (a), (b), (c), and (d) in the preferred ratios, the balance of the structural units is favorable, resulting in an excellent ability to inhibit the precipitation of silicate and silica polymer.
[0018] The copolymer may have a structural unit (e) derived from a monomer (E) other than the unsaturated carboxylic acid monomer (A), the sulfonic acid group-containing monomer (B), the polyalkylene glycol monomer (C), and the hydrophobic monomer (D). The proportion of the structural unit (e) in the copolymer is preferably 0 to 30% by mass relative to 100% by mass of all structural units. It is more preferably 0 to 20% by mass, even more preferably 0 to 10% by mass, particularly preferably 0 to 5% by mass, and most preferably 0% by mass.
[0019] The copolymer preferably has a weight-average molecular weight of 10,000 to 200,000. This results in superior precipitation suppression ability for magnesium silicate and silica polymer. The weight-average molecular weight is more preferably 15,000 to 100,000, even more preferably 30,000 to 85,000, and particularly preferably 40,000 to 75,000. In one embodiment, the weight-average molecular weight is also preferably 50,000 to 170,000. The weight-average molecular weight can be measured by the method described in the Examples.
[0020] <Unsaturated Carboxylic Acid Monomer (A)> The unsaturated carboxylic acid monomer (A) is not particularly limited as long as it has a carboxyl group or a salt thereof and an ethylenically unsaturated hydrocarbon group (unsaturated group), but may be a monomer represented by the following formula (6):
[0021]
[0022] (In the formula, R １３ , R １４ , R １５ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, -(CH ２ ) ｐ１ COOM ２ (-(CH ２ ) ｐ１ COOM ２ Is -COOM １ or other -(CH ２ ) ｐ１ COOM ２ and an anhydride may be formed), -(CH ２ ) ｐ２ (CO) ｑ１ -O-R １６ , or -(CH ２ ) ｐ３ CONR １７ R １８ p1, p2, and p3 are the same or different and each represents an integer of 0 to 2, and q1 represents 0 or 1. M １ and M ２ R are the same or different and represent a hydrogen atom, a monovalent metal atom, a divalent metal atom, a trivalent metal atom, a quaternary ammonium group, or an organic amine group. １６ , R １７ , R １８ are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.
[0023] The above R １３ , R １４ , R １５The number of carbon atoms in the alkyl group having 1 to 10 carbon atoms in the above formula is preferably 1 to 8, more preferably 1 to 4. The alkyl group having 1 to 10 carbon atoms is preferably a methyl group, an ethyl group, a propyl group, or a butyl group, more preferably a methyl group or an ethyl group, and particularly preferably a methyl group. １３ , R １４ , R １５ At least one of these is preferably a hydrogen atom, and more preferably at least two of these are hydrogen atoms.
[0024] The above R １６ , R １７ , R １８ Examples of the hydrocarbon group having 1 to 30 carbon atoms include an aliphatic alkyl group having 1 to 30 carbon atoms, an alicyclic alkyl group having 3 to 20 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, and an aryl group having 6 to 30 carbon atoms.
[0025] The above M １ and M ２ Examples of the monovalent metal atom in the above formula include alkali metal atoms such as lithium, sodium, and potassium. Examples of the divalent metal atom include alkaline earth metal atoms such as calcium and magnesium. Examples of the trivalent metal atom include aluminum and iron. Examples of the organic amine group include alkanolamine groups such as ethanolamine group, diethanolamine group, and triethanolamine group, and triethylamine group. １ and M ２ is preferably a hydrogen atom or an alkali metal atom.
[0026] Specific examples of the unsaturated carboxylic acid monomer (A) include the following unsaturated monocarboxylic acid monomers and unsaturated dicarboxylic acid monomers. Examples of the unsaturated monocarboxylic acid monomers include (meth)acrylic acid, crotonic acid, isocrotonic acid, tiglic acid, 3-methylcrotonic acid, 2-methyl-2-pentenoic acid, α-hydroxyacrylic acid, and the like; their monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts; half esters of the following unsaturated dicarboxylic acid monomers and alcohols having 1 to 22 carbon atoms or glycols having 2 to 4 carbon atoms; and half amides of unsaturated dicarboxylic acid monomers and amines having 1 to 22 carbon atoms.
[0027] Examples of the alcohol having 1 to 22 carbon atoms include methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonaol, decanol, undecanol, dodecanol, tridecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol, nonadecanol, and icosanol.
[0028] Examples of the glycol having 2 to 4 carbon atoms include ethylene glycol, propylene glycol, and diethylene glycol.
[0029] Examples of the amine having 1 to 22 carbon atoms include methylamine, ethylamine, propylamine, butylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, pentylamine, dipentylamine, hexylamine, dihexylamine, heptylamine, diheptylamine, octylamine, dioctylamine, and dodecylamine.
[0030] The unsaturated dicarboxylic acid monomer may be any monomer having one unsaturated group and two groups capable of forming a carbanion in the molecule, and examples thereof include maleic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, etc., as well as their monovalent metal salts, divalent metal salts, ammonium salts, organic amine salts, and anhydrides. The unsaturated carboxylic acid monomer (A) is preferably (meth)acrylic acid (salt), maleic acid (salt), or maleic anhydride. From the viewpoint of improving polymerizability, (meth)acrylic acid (salt) is more preferred.
[0031] <Sulfonic Acid Group-Containing Monomer (B)> The sulfonic acid group-containing monomer (B) is not particularly limited as long as it has a sulfonic acid group or a salt thereof and an ethylenically unsaturated hydrocarbon group, and examples thereof include 3-(meth)allyloxy-2-hydroxypropanesulfonic acid, 2-(meth)allyloxyethylenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, p-styrenesulfonic acid, α-methyl-p-styrenesulfonic acid, vinylsulfonic acid, vinylsulfamic acid, (meth)allyl sulfonic acid, isoprenesulfonic acid, 4-(allyloxy)benzenesulfonic acid, and the like. Examples of the salt include 2-acrylamido-1-methylpropanesulfonic acid, 2-acrylamidopropanesulfonic acid, 2-acrylamido-n-butanesulfonic acid, 2-acrylamido-2-phenylpropanesulfonic acid, 2-((meth)acryloyloxy)ethanesulfonic acid, 2-(meth)allyloxyethylenesulfonic acid, and salts thereof. The salt is not particularly limited, and examples thereof include the M １ and M ２ Examples of the salts include the same as those in
[0032] The sulfonic acid group-containing monomer (B) is preferably 2-acrylamido-1-methylpropanesulfonic acid or a salt thereof, or a monomer represented by the following formula (7):
[0033] (In the formula, R １９ represents a hydrogen atom or a methyl group. ２０is CH ２ Group, CH ２ CH ２ represents a group or a direct bond. ２ and Y ２ are each independently a hydroxyl group or —SO ３ M ３ represents M ３ represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group (wherein X ２ , Y ２ At least one of the following is -SO ３ M ３ It is a monomer represented by the formula:
[0034] R in the above formula (7) １９ represents a hydrogen atom or a methyl group, and is preferably a hydrogen atom. ２０ is CH ２ Group, CH ２ CH ２ represents a group or a direct bond, preferably CH ２ X in the above formula (7) is a group. ２ , Y ２ are each independently a hydroxyl group or —SO ３ M ３ represents X ２ , Y ２ At least one of the groups is -SO ３ M ３ In order to more fully exhibit the effects of the present invention, X ２ , Y ２ Only one of the two is -SO ３ M ３ It is preferable that M ３ represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group. ３ When is a metal atom, an ammonium group, or an organic amine group, -SO ３ M ３ represents a metal salt, an ammonium salt or an organic amine salt of a sulfonic acid. ３ The metal atom and organic amine group in １ and M ２ The same metal atoms and organic amine groups as those in M ３is preferably a hydrogen atom, an alkali metal atom, or an ammonium group, more preferably a hydrogen atom, sodium, or potassium, and even more preferably a hydrogen atom or sodium.
[0035] The sulfonic acid group-containing monomer (B) is more preferably a monomer represented by the above formula (7), and even more preferably 3-(meth)allyloxy-2-hydroxypropanesulfonic acid or a salt thereof. The monomer represented by the above formula (7) has a hydroxyl group in its structure and contributes to improving the solubility of the polymer after polymerization, particularly for polymers with large molecular weights.
[0036] <Polyalkylene glycol-based monomer (C)> The polyalkylene glycol-based monomer (C) is a monomer represented by the following formula (1):
[0037] (In the formula, R １ , R ２ and R ３ are the same or different and represent a hydrogen atom or a methyl group. ４ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. (R ５ O) are the same or different and represent an oxyalkylene group having 2 to 18 carbon atoms. n represents the average number of moles of oxyalkylene groups added and is a number from 10 to 200. x1 represents a number from 0 to 4. y1 represents 0 or 1.
[0038] In the above formula (1), R １ ~R ３ are the same or different and represent a hydrogen atom or a methyl group. １ , R ２ is a hydrogen atom, and R ３ is a hydrogen atom or a methyl group. More preferably, R １ , R ２ is a hydrogen atom, and R ３ is a methyl group.
[0039] R in the above formula (1) ４represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. It is preferably a hydrocarbon group having 1 to 20 carbon atoms or a hydrogen atom, more preferably a hydrogen atom or a hydrocarbon group having 1 to 15 carbon atoms, even more preferably a hydrogen atom or a hydrocarbon group having 1 to 15 carbon atoms, particularly preferably a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, and most preferably a hydrogen atom.
[0040] Examples of the hydrocarbon group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an n-pentyl group (an amyl group), an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, an n-nonadecyl group, an n-icosyl group, an i-propyl group, a sec-butyl group, an i-butyl group, a t-butyl group, a 1-methylbutyl group, a 1-ethylpropyl group, a 2-methyl ... aliphatic alkyl groups such as butyl butyl group, i-amyl group, neopentyl group, 1,2-dimethylpropyl group, 1,1-dimethylpropyl group, t-amyl group, 1,3-dimethylbutyl group, 3,3-dimethylbutyl group, 2-ethylbutyl group, 2-ethyl-2-methylpropyl group, 1-methylheptyl group, 2-ethylhexyl group, 1,5-dimethylhexyl group, t-octyl group, branched nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, stearyl group, and icosyl group; groups; alicyclic alkyl groups such as a cyclopropyl group, a cyclopropylmethyl group, a cyclobutyl group, a cyclobutylmethyl group, a cyclopentyl group, a cyclohexyl group, a cyclohexylmethyl group, a cycloheptyl group, a cyclooctyl group, a cyclohexylpropyl group, a cyclododecyl group, a norbornyl group (C7), an adamantyl group (C10), or a cyclopentylethyl group; a vinyl group, an allyl group, a 1-butenyl group, a 2-butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, a dodecenyl group, or an octadecenyl group; Examples thereof include alkenyl groups such as icosenyl groups; alkynyl groups such as ethynyl groups, 1-propynyl groups, 2-propynyl groups, butynyl groups, pentynyl groups, hexynyl groups, heptynyl groups, octynyl groups, nonynyl groups, decynyl groups, dodecynyl groups, octadecynyl groups, and icosinyl groups; and aryl groups such as phenyl groups, benzyl groups, phenethyl groups, o-, m-, or p-tolyl groups, 2,3-, or 2,4-xylyl groups, mesityl groups, naphthyl groups, anthryl groups, phenanthryl groups, biphenylyl groups, benzhydryl groups, trityl groups, and pyrenyl groups. Among these, aliphatic alkyl groups and alicyclic alkyl groups are preferred.
[0041] In the above formula (1), R ５ O represents an oxyalkylene group having 2 to 18 carbon atoms, and n Os are present in the polyalkylene glycol. ５ This means that all of the oxyalkylene groups represented by O may be the same or different. The number of carbon atoms in the oxyalkylene group is preferably 2 to 18, more preferably 2 to 12, even more preferably 2 to 8, and particularly preferably 2 to 4. In the above formula (1), R ５ The oxyalkylene group represented by O is an alkylene oxide adduct, and examples of such alkylene oxides include alkylene oxides having 2 to 8 carbon atoms, such as ethylene oxide, propylene oxide, butylene oxide, isobutylene oxide, 1-butene oxide, 2-butene oxide, and styrene oxide. More preferred are alkylene oxides having 2 to 4 carbon atoms, such as ethylene oxide, propylene oxide, and butylene oxide, and even more preferred are ethylene oxide and propylene oxide. Furthermore, when the polyalkylene glycol is an alkylene oxide adduct of any two or more types of alkylene oxide selected from ethylene oxide, propylene oxide, butylene oxide, styrene oxide, and the like, the adduct may be in any form, such as random addition, block addition, or alternating addition. In order to ensure a balance between hydrophilicity and hydrophobicity, it is preferable that the oxyalkylene groups in the polyalkylene glycol contain oxyethylene groups as an essential component, more preferably 50 mol % or more of oxyethylene groups, and even more preferably 90 mol % or more of oxyethylene groups.
[0042] In the above formula (1), n represents the average number of moles of oxyalkylene groups added and is 1 to 300. n is preferably 5 to 200, more preferably 8 to 100, even more preferably 10 to 85, still more preferably 20 to 70, and particularly preferably 40 to 60.
[0043] In the above formula (1), x1 represents a number from 0 to 4, and y1 represents 0 or 1. x1 is preferably 1 to 4. y1 is preferably 0. Since the monomer (A) in which y1 is 0 is inexpensive, the copolymer of the present invention can be produced at low cost. When y1 is 0, x1 is preferably 1 to 4, more preferably 1 or 2, and even more preferably 2. When x1 is 1 to 4, R ３ is preferably a methyl group. When y1 is 1, x1 is preferably 0. In this case, R ３ is more preferably a hydrogen atom or a methyl group.
[0044] Specific examples of the polyalkylene glycol monomer (A) include (poly)alkylene glycol (meth)acrylates such as polyethylene glycol (meth)acrylate and alkoxy (poly)alkylene glycol (meth)acrylates in which the terminals of these are hydrophobically modified with a hydrocarbon group having 1 to 30 carbon atoms; compounds in which 1 to 300 moles of alkylene oxide are added to unsaturated alcohols having 2 to 8 carbon atoms such as vinyl alcohol, allyl alcohol, methallyl alcohol, 3-methyl-3-buten-1-ol, 3-methyl-2-buten-1-ol, 2-methyl-3-buten-1-ol, 2-methyl-2-buten-1-ol, and 3-allyloxy-1,2-propanediol; and compounds in which the terminals of these are hydrophobically modified with a hydrocarbon group having 1 to 30 carbon atoms. Among these, compounds in which 1 to 300 moles of alkylene oxide are added to unsaturated alcohols having 2 to 8 carbon atoms and compounds in which the terminals of these are hydrophobically modified with a hydrocarbon group having 1 to 30 carbon atoms are preferred. More preferred are compounds in which 1 to 300 moles of alkylene oxide are added to unsaturated alcohols having 2 to 8 carbon atoms, and even more preferred are compounds in which alkylene oxide is added to (meth)allyl alcohol or 3-methyl-3-buten-1-ol.
[0045] <Hydrophobic Monomer (D)> The hydrophobic monomer (D) may be any hydrophobic monomer, but is preferably a monomer having an ethylenically unsaturated group and a hydrocarbon group having 4 to 18 carbon atoms, which may have a heteroatom. The hydrocarbon group preferably has 4 to 12 carbon atoms, even more preferably 4 to 8 carbon atoms, even more preferably 4 to 6 carbon atoms, and particularly preferably 4 to 5 carbon atoms. As long as the hydrocarbon group exhibits hydrophobicity, it may have a heteroatom such as a nitrogen atom, sulfur atom, oxygen atom, phosphorus atom, or halogen atom. A carbon atom or hydrogen atom constituting the hydrocarbon group may be substituted with a heteroatom, or the hydrocarbon group may have a substituent having a heteroatom. Examples of the substituent having a heteroatom include, but are not limited to, a hydroxyl group, an ether group, an alkoxy group, a carboxyl group, an acyl group, a sulfonic acid group, an amino group, and a phosphate group. A more preferred hydrophobic monomer (D) is a monomer represented by the following formula (2):
[0046] (In the formula, R ６ , R ７ and R ８ are the same or different and represent a hydrogen atom or a methyl group. x2 represents a number from 0 to 4. y2 represents 0 or 1. Z represents a hydrocarbon group having 4 to 18 carbon atoms or a group represented by the following formula (3):
[0047] (In the formula, X １ , Y １ represents a hydroxyl group or a group represented by the following formula (4) or (5), and X １ , Y １ One of the groups is a hydroxyl group, and the other is a group represented by the following formula (4) or (5):
[0048] (In the formula, R ９ are the same or different and represent an alkylene group having 2 to 4 carbon atoms. m is an oxyalkylene group (—O—R ９ -) and represents a number from 0 to 5. １０ represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms. １１ , R １２ are the same or different and represent an alkyl group having 1 to 18 carbon atoms.１１ , R １２ The total number of carbon atoms is 4 or more.
[0049] In the above formula (2), x2 represents a number from 0 to 4, and y2 represents 0 or 1. In the above formula (2), when Z is a hydrocarbon group having 4 to 18 carbon atoms, it is preferable that x2 is 0 and y2 is 1. In the above formula (2), when Z is a group represented by the above formula (3), it is preferable that x2 is 1 to 4, more preferably 1 or 2, and y2 is 0.
[0050] In the above formula (2), R ６ ~R ８ are the same or different and represent a hydrogen atom or a methyl group. ６ , R ７ is a hydrogen atom, and R ８ is a hydrogen atom or a methyl group. More preferably, R ６ ~R ８ is a hydrogen atom.
[0051] In the above formula (2), Z is a hydrocarbon group having 4 to 18 carbon atoms, or a group represented by the above formula (3). The number of carbon atoms in the hydrocarbon group in Z is preferably 4 to 12, more preferably 4 to 8, even more preferably 4 to 6, and particularly preferably 4 to 5. The hydrocarbon group in Z is not particularly limited as long as it has 4 or more carbon atoms, and examples thereof include an aliphatic alkyl group, an alicyclic alkyl group, an alkenyl group, an alkynyl group, and an aryl group. Specific examples of these include R in the above formula (1). ４ Examples include those mentioned above.
[0052] The hydrocarbon group for Z is preferably an aliphatic alkyl group or an alicyclic alkyl group, more preferably an aliphatic alkyl group, and even more preferably an n-butyl group, a t-butyl group, an isobutyl group, a pentyl group, or a hexyl group.
[0053] In the above formula (3), X １ , Y １ is a hydroxyl group or a group represented by the above formula (4) or (5). １ , Y １One of the groups is a hydroxyl group, and the other is a group represented by the above formula (4).
[0054] In the above formula (4), R ９ are the same or different and represent an alkylene group having 2 to 4 carbon atoms. Examples of the alkylene group having 2 to 4 carbon atoms include an ethylene group, a propylene group, and a butylene group. From the viewpoint of improving the polymerizability of the hydrophobic monomer (D), an alkylene group having 2 to 3 carbon atoms, such as an ethylene group or a propylene group, is preferred. One or more types of the alkylene group can be used. In the general formulas (4) and (5), m represents an oxyalkylene group (-O-R ９ -) and represents a number of 0 to 5. m is preferably 0 to 4, more preferably 0 to 3, still more preferably 0 to 2, particularly preferably 0 or 1, and most preferably 0.
[0055] In the above formula (4), R １０ represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, preferably an alkyl group having 1 to 18 carbon atoms. １０ The number of carbon atoms in R is preferably 2 to 12, more preferably 3 to 8, still more preferably 4 to 6, and particularly preferably 4 or 5. １０ Specific examples of the alkyl group include R ４ Preferred are a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an isobutyl group, a pentyl group, and a hexyl group, and more preferred are an n-butyl group, a t-butyl group, an isobutyl group, a pentyl group, and a hexyl group.
[0056] In the above formula (5), R １１ , R １２ are the same or different and are alkyl groups having 1 to 18 carbon atoms, and R １１ , R １２ The total number of carbon atoms in R is 4 or more. １１ , R １２ The total number of carbon atoms in R is preferably 4 to 18, and more preferably 6 to 12. １１ , R １２ Specific examples of the alkyl group include R ４Preferred are an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an isobutyl group, a pentyl group, and a hexyl group.
[0057] Specific examples of the monomer represented by the above formula (2) include alkyl (meth)acrylates having an alkyl group having 4 to 18 carbon atoms, such as butyl (meth)acrylate and pentyl (meth)acrylate, and reaction products of compounds having a carbon-carbon double bond and an epoxy ring, such as (meth)allyl glycidyl ether and vinyl glycidyl ether, with alcohols having 4 to 18 carbon atoms and / or amine compounds having an alkyl group having 1 to 18 carbon atoms. Preferably, it is a reaction product of (meth)allyl glycidyl ether and alcohols having 4 to 18 carbon atoms.
[0058] Examples of the alcohol having 4 to 18 carbon atoms include butanol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, dodecyl alcohol (lauryl alcohol), etc. Examples of the amine compound having an alkyl group having 1 to 18 carbon atoms include di-n-isopropylamine, di-n-butylamine, etc.
[0059] The method for preparing the monomer represented by formula (2) is not particularly limited, and the monomer can be prepared by any appropriate method. A simple example of such a preparation method is a method in which the epoxy ring of a compound having a carbon-carbon double bond and an epoxy ring is reacted with the hydroxyl group and / or amino group of an amine compound having an alcohol having 4 to 18 carbon atoms and / or an alkyl group having 1 to 18 carbon atoms. The reaction may be carried out without a catalyst, or may be carried out in the presence of an acidic catalyst such as boron trifluoride, or a basic catalyst such as sodium hydroxide or potassium hydroxide.
[0060] <Other Monomers (E)> The copolymer of the present invention may have a structural unit (e) derived from a monomer (E) other than the monomers (A) to (D). Other monomers (E) are not particularly limited as long as they can be copolymerized with the monomers (A) to (D), and examples thereof include N-vinyl lactam monomers such as N-vinylpyrrolidone; (meth)acrylic acid esters having an alkyl group having 1 to 3 carbon atoms such as methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate; hydroxyl group-containing (meth)acrylic acid esters such as hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxy-1-methylethyl (meth)acrylate, 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and hydroxypentyl (meth)acrylate; (meth)acrylamide, N-monomethyl (meth)acrylamide, N vinyl aryl monomers such as styrene, α-methylstyrene, vinyltoluene, indene, vinylnaphthalene, phenylmaleimide, vinylaniline, etc.; alkenes such as ethylene, propylene, butadiene, isobutylene, octene, etc.; vinyl carboxylates such as vinyl acetate, vinyl propionate, etc.; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, etc.; vinyl ethylene carbonate and derivatives thereof; unsaturated amines such as N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylamide, vinylpyridine, vinylimidazole, and salts or quaternized products thereof;
[0061] [Method for producing polycarboxylic acid copolymer] The production of the polycarboxylic acid copolymer of the present invention is not particularly limited, but can be produced by polymerizing monomer components, specific and preferred examples of which are as described above. The content ratio of each monomer component relative to 100% by mass of all monomer components can be determined based on the ratio of the structural units (a) to (e) relative to 100% by mass of all structural units described above.
[0062] In producing the copolymer, a chain transfer agent can be used to adjust the molecular weight of the resulting polymer. Examples of chain transfer agents include thiol-based chain transfer agents such as mercaptoethanol, thioglycerol, thioglycolic acid, 3-mercaptopropionic acid, thiomalic acid, and 2-mercaptoethanesulfonic acid; secondary alcohols such as isopropyl alcohol; and hydrophilic chain transfer agents such as lower oxides and salts of phosphorous acid, hypophosphorous acid, and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, hydrogen sulfite, dithionous acid, metabisulfite, and salts thereof (sodium sulfite, sodium hydrogen sulfite, sodium dithionite, sodium metabisulfite, etc.). Thiol-based chain transfer agents are preferred.
[0063] The amount of the chain transfer agent used may be appropriately determined, but is preferably 0.1 mol or more, more preferably 0.25 mol or more, and even more preferably 0.5 mol or more, relative to 100 mol of the total amount of the monomer components, and is preferably 10 mol or less, more preferably 7 mol or less, and even more preferably 5 mol or less.
[0064] The polymerization reaction can be carried out by a method such as solution polymerization or bulk polymerization, using a radical polymerization initiator as necessary. Solution polymerization can be carried out batchwise or continuously, or a combination thereof, and examples of the solvent used in this case include water; alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, cyclohexane, and n-hexane; ester compounds such as ethyl acetate; ketone compounds such as acetone and methyl ethyl ketone; and cyclic ether compounds such as tetrahydrofuran and dioxane. Among these, polymerization by aqueous solution polymerization is preferred.
[0065] When the aqueous solution polymerization is carried out, a water-soluble polymerization initiator is used as the radical polymerization initiator, for example, a persulfate such as ammonium persulfate, sodium persulfate, or potassium persulfate; hydrogen peroxide; azoamidine compounds such as 2,2'-azobis-2-methylpropionamidine hydrochloride; cyclic azoamidine compounds such as 2,2'-azobis-2-(2-imidazolin-2-yl)propane hydrochloride; or azonitrile compounds such as 2-carbamoylazoisobutyronitrile. In this case, an accelerator such as an alkali metal sulfite such as sodium hydrogensulfite, metabisulfite, sodium hypophosphite, Fe(II) salts such as Mohr's salt, sodium hydroxymethanesulfinate dihydrate, hydroxylamine hydrochloride, thiourea, L-ascorbic acid (salt), or erythorbic acid (salt) may also be used in combination. Among these, persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate, and combinations of hydrogen peroxide with an accelerator such as L-ascorbic acid (salt) are preferred. A combination of hydrogen peroxide and L-ascorbic acid (salt) is even more preferred. These radical polymerization initiators and accelerators may be used alone or in combination of two or more. Furthermore, when solution polymerization is performed using a lower alcohol, an aromatic or aliphatic hydrocarbon, an ester compound, or a ketone compound as the solvent, or when bulk polymerization is performed, peroxides such as benzoyl peroxide, lauroyl peroxide, and sodium peroxide; hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide; and azo compounds such as azobisisobutyronitrile are used as radical polymerization initiators. In this case, accelerators such as amine compounds can also be used in combination. Furthermore, when a water-lower alcohol mixed solvent is used, the radical polymerization initiators or combinations of radical polymerization initiators and accelerators described above can be appropriately selected and used.
[0066] The amount of the radical polymerization initiator used is preferably 0.001 mol or more, more preferably 0.01 mol or more, even more preferably 0.1 mol or more, particularly preferably 0.2 mol or more, relative to 100 mol of the total amount of the monomer components, and is preferably 20 mol or less, even more preferably 10 mol or less, particularly preferably 5 mol or less, and most preferably 3 mol or less.
[0067] In the polymerization reaction, polymerization conditions such as polymerization temperature are appropriately determined depending on the polymerization method, solvent, polymerization initiator, and chain transfer agent used, but the polymerization temperature is preferably 0°C or higher and 110°C or lower, more preferably 30°C or higher, and even more preferably 50°C or higher, and more preferably 100°C or lower, and even more preferably 80°C or lower.
[0068] The method for adding each monomer component to the reaction vessel is not particularly limited, and examples include a method in which the entire amount is added to the reaction vessel all at once at the beginning; a method in which the entire amount is added to the reaction vessel in portions or continuously; a method in which a portion is added to the reaction vessel initially and the remainder is added to the reaction vessel in portions or continuously. Furthermore, the addition rate of each monomer to the reaction vessel may be changed continuously or stepwise during the reaction, thereby changing the weight ratio of each monomer added per unit time continuously or stepwise, thereby simultaneously synthesizing two or more copolymers with different monomer ratios during the polymerization reaction. The radical polymerization initiator may be charged to the reaction vessel from the beginning, or may be added dropwise to the reaction vessel, or a combination of these may be used depending on the purpose.
[0069] [Uses of Polycarboxylic Acid Copolymer] The polycarboxylic acid copolymer of the present invention can be used as a water treatment agent (scaling inhibitor, anticorrosion agent, etc.), a fiber treatment agent, a dispersant, a bleach stabilizer, a metal ion sequestering agent, a thickener, various binders, an emulsifier, a skin care agent, a hair care agent, etc. Use of the copolymer of the present invention for these purposes is also an embodiment of the present invention. A method of using the polycarboxylic acid copolymer of the present invention as a water treatment agent is also one aspect of the present invention.
[0070] The water treatment agent is useful for preventing scale formation in cooling water circulation systems, boiler water circulation systems, seawater desalination plants, reverse osmosis membrane treatment plants, pulp digesters, black liquor concentration plants, etc. A silica scale inhibitor containing the polycarboxylic acid copolymer of the present invention is also one embodiment of the present invention. The water treatment agent may also contain any appropriate water-soluble polymer as long as its performance and effects are not affected.
[0071] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" means "parts by weight" and "%" means "% by mass."
[0072] <Gel Permeation Chromatography (GPC)> The weight average molecular weight of the copolymer was measured by the following method. Apparatus: Alliance (e2695) manufactured by Waters Analysis software: Empower Professional + GPC option manufactured by Waters Column used: SHODEX OHpak SB-G 6G, SB-806M (3 units) manufactured by Showa Denko K.K. Detector: Refractive index (RI) detector (Waters 2414), multi-wavelength visible ultraviolet (PDA) detector (Waters 2998) Eluent: Prepared by dissolving 137.79 g of sodium dihydrogen phosphate dihydrate and 316.31 g of disodium hydrogen phosphate dodecahydrate in a mixed solvent of 17,209.9 g of water and 1,536 g of acetonitrile Standard material for creating calibration curve: Polyacrylic manufactured by American Polymer Standards Corporation Acid standard [Peak top molecular weight (Mp) 204, 900, 1250, 4100, 16000, 62900, 392600, 1310000, 2250000] Calibration curve: Created using a cubic equation based on the Mp and elution time of the above standard substance. Flow rate: 1.0 ml / min. Column temperature: 40°C. Measurement time: 45 minutes. Sample solution injection volume: 50 μL (eluent solution with a sample concentration of 0.5 wt%)
[0073] (GPC analysis conditions) In the obtained RI chromatogram, the flat and stable parts before the exclusion limit and after the elution limit were connected with a straight line as the baseline, and the polymer part was detected and analyzed. However, when the peaks of the monomer or monomer-derived impurities were measured to overlap partially with the polymer peak, they were vertically divided at the deepest part of the overlapping part with the polymer to separate the polymer part and the monomer part, and the molecular weight and molecular weight distribution of only the polymer part were measured. When the polymer part completely overlapped with other parts and could not be separated, they were calculated together.
[0074] <Evaluation of magnesium silicate production inhibitory ability> Preparation of boric acid buffer solution: 7.420 g of boric acid, 1.753 g of sodium chloride, and 19.069 g of sodium borate decahydrate were mixed with ion-exchanged water to make a total of 1000 g. Preparation of magnesium aqueous solution: 8.115 g of magnesium sulfate heptahydrate were mixed with ion-exchanged water to make a total of 1000 g. Preparation of silica aqueous solution: 2.129 g of sodium metasilicate nonahydrate were mixed with ion-exchanged water to make a total of 150 g.
[0075] Testing at a polymer concentration of 50 ppm: 71.0 g of ion-exchanged water, 4.0 g of boric acid buffer solution, 10.0 g of silica aqueous solution, and 5.0 g of polymer aqueous solution diluted to 0.1% were added to a container in this order while stirring, and 10.0 g of magnesium aqueous solution was further added. The mixture was then stirred for 18 hours in a warm bath at 60°C. After 18 hours, the mixture was subjected to suction filtration using a polyethersulfone (PES) membrane (manufactured by AS ONE Corporation) with 0.1 μm openings. The resulting filtrate was measured for its Si concentration by ICP (atomic emission spectroscopy), and the SiO ２ Converted.
[0076] When evaluating at a polymer concentration other than 50 ppm, the amounts of ion-exchanged water and the aqueous polymer solution added were adjusted so that the total amount did not change. The polymer concentration was changed in 5 ppm increments to evaluate the SiO ２ The amount of addition that can maintain the concentration at 200 ppm or more was determined as the minimum amount of addition required to inhibit silica scale.
[0077] <Evaluation of silica polymer suppression ability> Preparation of silica aqueous solution: Ion-exchanged water was added to 14.2 g of sodium metasilicate nonahydrate to make a total of 1000 g. Preparation of sodium hydrogen carbonate aqueous solution: Ion-exchanged water was added to 4.2 g of sodium hydrogen carbonate to make a total of 1000 g.
[0078] 4.0 g of silica aqueous solution, 26.2 g of ion-exchanged water, 4.0 g of sodium bicarbonate aqueous solution, and 1.6 g of polymer aqueous solution diluted to 0.1% were charged into a vessel and stirred. 4.210 g of 0.1 M hydrochloric acid was further added while stirring. The mixture was then left to stand in a warm bath at 30°C for 7 days. After 7 days, the ionic Si concentration was measured using the molybdenum yellow method (JIS K 0101). The silica polymerization inhibition rate was calculated according to the following formula: Silica polymerization inhibition rate (%) = ionic Si concentration in liquid (ppm) / Si concentration in feed (ppm)
[0079] Example 1 (1) Monomer Synthesis 370.0 parts of n-butyl alcohol and 4.3 parts of sodium hydroxide were charged into a glass reaction vessel equipped with a thermometer, a stirrer (paddle blade), and a reflux condenser, and the temperature was raised to 60°C while stirring. Next, 57.0 parts of allyl glycidyl ether (hereinafter also referred to as "AGE") was added over 30 minutes, and the mixture was then allowed to react for 5 hours. This solution was transferred to a recovery flask, and the solvent was removed using a rotary evaporator. 200.0 parts of a 20% by weight aqueous sodium chloride solution was added thereto, and the solution was transferred to a separatory funnel. After shaking well, the mixture was allowed to stand until the layers separated, and the lower layer was removed. The remaining upper layer was transferred to a recovery flask, and the solvent was removed using a rotary evaporator. The precipitated salt was removed by filtration, yielding Monomer (1). (2) Polymerization A glass reaction vessel equipped with a thermometer, a stirrer (paddle blade), a dropping funnel, a nitrogen inlet tube, and a reflux condenser was charged with 96.9 parts of water, and the atmosphere inside the reaction vessel was replaced with nitrogen while stirring. The temperature was raised to 60°C under a nitrogen atmosphere, and then 3.1 parts of 35% aqueous hydrogen peroxide was added to the reaction vessel. After the temperature stabilized at 60°C, mixed solution 1, which was a mixture of 101.1 parts of acrylic acid (hereinafter also referred to as "AA"), 41.9 parts of a 50% aqueous solution of sodium 2-acrylamido-2-methylpropanesulfonate (hereinafter also referred to as "50% AMPS"), 70.0 parts of an unsaturated polyalkylene glycol ether monomer in which an average of 50 moles of ethylene oxide were added to 3-methyl-3-buten-1-ol (hereinafter also referred to as "IPN-50"), 10.0 parts of monomer (1), and 27.0 parts of water, and mixed solution 2, which was a mixture of 0.3 parts of L-ascorbic acid, 4.2 parts of 2-mercaptopropionic acid, and 45.5 parts of water, were simultaneously added dropwise from separate nozzles. The addition was carried out continuously at a constant rate, and mixed solution 1 was added dropwise in its entirety over 150 minutes, and mixed solution 2 was added dropwise in its entirety over 210 minutes. After the dropwise addition of the mixed solution 2 was completed, the reaction vessel was maintained at 60° C. for an additional 60 minutes to complete the polymerization reaction, thereby obtaining the polymer (1) of the present disclosure.
[0080] Example 2 A glass reaction vessel equipped with a thermometer, a stirrer (paddle blade), a dropping funnel, a nitrogen inlet tube, and a reflux condenser was charged with 96.9 parts of water, and the atmosphere inside the reaction vessel was replaced with nitrogen while stirring. The temperature was raised to 60°C under a nitrogen atmosphere, and then 3.1 parts of 35% hydrogen peroxide solution was added to the reaction vessel. After the temperature stabilized at 60°C, Mixed Solution 1, which was a mixture of AA (101.1 parts), 50% AMPS (41.9 parts), IPN-50 (70.0 parts), monomer (1) (10.0 parts), and water (9.5 parts), and Mixed Solution 2, which was a mixture of L-ascorbic acid (0.3 parts), 2-mercaptopropionic acid (2.5 parts), and water (47.2 parts), were simultaneously added dropwise from separate nozzles. The addition was carried out continuously at a constant rate, with Mixed Solution 1 being added dropwise over 150 minutes and Mixed Solution 2 being added dropwise over 210 minutes. After the dropwise addition of the mixed solution 2 was completed, the reaction vessel was maintained at 60° C. for an additional 60 minutes to complete the polymerization reaction, thereby obtaining a polymer (2) of the present disclosure.
[0081] Example 3 A glass reaction vessel equipped with a thermometer, a stirrer (paddle blade), a dropping funnel, a nitrogen inlet tube, and a reflux condenser was charged with 97.9 parts of water, and the atmosphere inside the reaction vessel was replaced with nitrogen while stirring. The temperature was raised to 60°C under a nitrogen atmosphere, and then 2.1 parts of 35% hydrogen peroxide solution was added to the reaction vessel. After the temperature stabilized at 60°C, Mixed Solution 1, which was a mixture of AA (67.4 parts), 50% AMPS (28.0 parts), IPN-50 (110.0 parts), monomer (1) (10.0 parts), and water (34.7 parts), and Mixed Solution 2, which was a mixture of L-ascorbic acid (0.2 parts), 2-mercaptopropionic acid (2.9 parts), and water (46.9 parts), were simultaneously added dropwise from separate nozzles. The addition was carried out continuously at a constant rate, with Mixed Solution 1 being added dropwise over 150 minutes and Mixed Solution 2 being added dropwise over 210 minutes. After the dropwise addition of the mixed solution 2 was completed, the reaction vessel was maintained at 60° C. for an additional 60 minutes to complete the polymerization reaction, thereby obtaining a polymer (3) of the present disclosure.
[0082] Example 4 A glass reaction vessel equipped with a thermometer, a stirrer (paddle blade), a dropping funnel, a nitrogen inlet tube, and a reflux condenser was charged with 97.9 parts of water, and the atmosphere inside the reaction vessel was replaced with nitrogen while stirring. After the temperature was raised to 60°C under a nitrogen atmosphere, 2.1 parts of 35% hydrogen peroxide solution was added to the reaction vessel. After the temperature stabilized at 60°C, Mixed Solution 1, which was a mixture of AA (67.4 parts), 50% AMPS (28.0 parts), IPN-50 (110.0 parts), monomer (1) (10.0 parts), and water (34.7 parts), and Mixed Solution 2, which was a mixture of L-ascorbic acid (0.2 parts), 2-mercaptopropionic acid (1.7 parts), and water (48.1 parts), were simultaneously added dropwise from separate nozzles. The addition was carried out continuously at a constant rate, with Mixed Solution 1 being added dropwise over 150 minutes and Mixed Solution 2 being added dropwise over 210 minutes. After the dropwise addition of the mixed solution 2 was completed, the reaction vessel was maintained at 60° C. for an additional 60 minutes to complete the polymerization reaction, thereby obtaining a polymer (4) of the present disclosure.
[0083] Example 5 A glass reaction vessel equipped with a thermometer, a stirrer (paddle blade), a dropping funnel, a nitrogen inlet tube, and a reflux condenser was charged with 95.8 parts of water, and the atmosphere in the reaction vessel was replaced with nitrogen while stirring. After the temperature was raised to 60°C under a nitrogen atmosphere, 4.2 parts of 35% hydrogen peroxide solution was added to the reaction vessel. After the temperature stabilized at 60°C, a mixture 1 containing AA (144.0 parts), 50% AMPS (17.7 parts), IPN-50 (32.0 parts), monomer (1) (16.0 parts), and water (40.3 parts) and a mixture 2 containing L-ascorbic acid (0.4 parts), 2-mercaptopropionic acid (2.5 parts), and water (47.1 parts) were simultaneously added dropwise from separate nozzles. The addition was carried out continuously at a constant rate, with the mixture 1 being added dropwise over 150 minutes and the mixture 2 being added dropwise over 210 minutes. After the dropwise addition of the mixed solution 2 was completed, the reaction vessel was maintained at 60° C. for an additional 60 minutes to complete the polymerization reaction, thereby obtaining a polymer (5) of the present disclosure.
[0084] Example 6 A glass reactor equipped with a thermometer, a stirrer (paddle blade), a dropping funnel, a nitrogen inlet tube, and a reflux condenser was charged with 87.3 parts of water, and the atmosphere inside the reactor was replaced with nitrogen while stirring. After the temperature was raised to 60°C under a nitrogen atmosphere, 2.7 parts of 35% hydrogen peroxide solution was added to the reactor. After the temperature stabilized at 60°C, Mixed Solution 1, which was a mixture of AA (77.4 parts), 50% AMPS (115.5 parts), IPN-50 (39.6 parts), monomer (1) (10.8 parts), and water (36.7 parts), and Mixed Solution 2, which was a mixture of L-ascorbic acid (0.2 parts), 2-mercaptopropionic acid (2.1 parts), and water (27.7 parts), were simultaneously added dropwise from separate nozzles. The addition was carried out continuously at a constant rate, with Mixed Solution 1 being added dropwise over 150 minutes and Mixed Solution 2 being added dropwise over 210 minutes. After the dropwise addition of the mixed solution 2 was completed, the reaction vessel was maintained at 60° C. for an additional 60 minutes to complete the polymerization reaction, thereby obtaining a polymer (6) of the present disclosure.
[0085] Example 7 A glass reaction vessel equipped with a thermometer, a stirrer (paddle blade), a dropping funnel, a nitrogen inlet tube, and a reflux condenser was charged with 96.9 parts of water, and the atmosphere inside the reaction vessel was replaced with nitrogen while stirring. After the temperature was raised to 60°C under a nitrogen atmosphere, 3.1 parts of 35% hydrogen peroxide solution was added to the reaction vessel. After the temperature stabilized at 60°C, a mixture 1 containing AA (101.1 parts), 50% AMPS (41.9 parts), IPN-50 (70.0 parts), monomer (1) (10.0 parts), and water (27.0 parts) and a mixture 2 containing L-ascorbic acid (0.3 parts), 2-mercaptopropionic acid (1.7 parts), and water (48.0 parts) were simultaneously added dropwise from separate nozzles. The addition was carried out continuously at a constant rate, with the mixture 1 being added dropwise over 150 minutes and the mixture 2 being added dropwise over 210 minutes. After the dropwise addition of the mixed solution 2 was completed, the reaction vessel was maintained at 60° C. for an additional 60 minutes to complete the polymerization reaction, thereby obtaining a polymer (7) of the present disclosure.
[0086] Example 8 A glass reaction vessel equipped with a thermometer, a stirrer (paddle blade), a dropping funnel, a nitrogen inlet tube, and a reflux condenser was charged with 87.2 parts of water, and the atmosphere inside the reaction vessel was replaced with nitrogen while stirring. The mixture was heated to 60°C under a nitrogen atmosphere, and then 2.8 parts of 35% hydrogen peroxide solution was added to the reaction vessel. After the temperature stabilized at 60°C, a mixture 1 containing AA (90.9 parts), a 40% aqueous solution of sodium 3-allyloxy-2-hydroxypropanesulfonate (hereinafter also referred to as "40% HAPS") (47.5 parts), IPN-50 (63.0 parts), monomer (1) (9.0 parts), and water (69.6 parts), and a mixture 2 containing L-ascorbic acid (0.3 parts), 2-mercaptopropionic acid (2.3 parts), and water (27.5 parts) were simultaneously added dropwise from separate nozzles. The dropwise addition was carried out continuously at a constant rate, and the entire amount of Mixture 1 was added dropwise over 150 minutes, and the entire amount of Mixture 2 was added dropwise over 210 minutes. After the dropwise addition of Mixture 2 was completed, the reaction vessel was maintained at 60°C for an additional 60 minutes to complete the polymerization reaction, thereby obtaining Polymer (8) of the present disclosure.
[0087] Example 9 A glass reaction vessel equipped with a thermometer, a stirrer (paddle blade), a dropping funnel, a nitrogen inlet tube, and a reflux condenser was charged with 87.2 parts of water, and the atmosphere inside the reaction vessel was replaced with nitrogen while stirring. After the temperature was raised to 60°C under a nitrogen atmosphere, 2.8 parts of 35% hydrogen peroxide solution was added to the reaction vessel. After the temperature stabilized at 60°C, Mixed Solution 1, which was a mixture of AA (90.0 parts), 40% HAPS (50.0 parts), IPN-50 (63.0 parts), monomer (1) (9.0 parts), and water (68.0 parts), and Mixed Solution 2, which was a mixture of L-ascorbic acid (0.2 parts), 2-mercaptopropionic acid (1.5 parts), and water (28.3 parts), were simultaneously added dropwise from separate nozzles. The addition was carried out continuously at a constant rate, and Mixed Solution 1 was added dropwise in its entirety over 150 minutes, and Mixed Solution 2 was added dropwise in its entirety over 210 minutes. After the dropwise addition of the mixed solution 2 was completed, the reaction vessel was maintained at 60° C. for an additional 60 minutes to complete the polymerization reaction, thereby obtaining a polymer (9) of the present disclosure.
[0088] Example 10 A glass reaction vessel equipped with a thermometer, a stirrer (paddle blade), a dropping funnel, a nitrogen inlet tube, and a reflux condenser was charged with 87.2 parts of water, and the atmosphere inside the reaction vessel was replaced with nitrogen while stirring. After the temperature was raised to 60°C under a nitrogen atmosphere, 2.8 parts of 35% hydrogen peroxide solution was added to the reaction vessel. After the temperature stabilized at 60°C, a mixture 1 containing AA (90.0 parts), 40% HAPS (50.0 parts), IPN-50 (63.0 parts), monomer (1) (9.0 parts), and water (68.0 parts) and a mixture 2 containing L-ascorbic acid (0.2 parts), 2-mercaptopropionic acid (1.3 parts), and water (28.5 parts) were simultaneously added dropwise from separate nozzles. The addition was carried out continuously at a constant rate, and the entire amount of mixture 1 was added dropwise over 150 minutes, and the entire amount of mixture 2 was added dropwise over 210 minutes. After the dropwise addition of the mixed solution 2 was completed, the reaction vessel was maintained at 60° C. for an additional 60 minutes to complete the polymerization reaction, thereby obtaining a polymer (10) of the present disclosure.
[0089] Example 11 A glass reaction vessel equipped with a thermometer, a stirrer (paddle blade), a dropping funnel, a nitrogen inlet tube, and a reflux condenser was charged with 87.1 parts of water, and the atmosphere inside the reaction vessel was replaced with nitrogen while stirring. After the temperature was raised to 60°C under a nitrogen atmosphere, 2.9 parts of 35% hydrogen peroxide solution was added to the reaction vessel. After the temperature stabilized at 60°C, a mixture 1 containing AA (99.0 parts), 40% HAPS (10.0 parts), IPN-50 (63.0 parts), monomer (1) (14.4 parts), and water (93.6 parts) and a mixture 2 containing L-ascorbic acid (0.3 parts), 2-mercaptopropionic acid (1.4 parts), and water (28.3 parts) were simultaneously added dropwise from separate nozzles. The addition was carried out continuously at a constant rate, with the entire amount of mixture 1 being added dropwise over 150 minutes and the entire amount of mixture 2 being added dropwise over 210 minutes. After the dropwise addition of the mixed solution 2 was completed, the reaction vessel was maintained at 60° C. for an additional 60 minutes to complete the polymerization reaction, thereby obtaining a polymer (11) of the present disclosure.
[0090] Example 12 A glass reaction vessel equipped with a thermometer, a stirrer (paddle blade), a dropping funnel, a nitrogen inlet tube, and a reflux condenser was charged with 87.2 parts of water, and the atmosphere in the reaction vessel was replaced with nitrogen while stirring. After the temperature was raised to 60°C under a nitrogen atmosphere, 2.8 parts of 35% hydrogen peroxide solution was added to the reaction vessel. After the temperature stabilized at 60°C, a mixture 1 containing AA (90.0 parts), 40% HAPS (25.0 parts), IPN-50 (54.0 parts), monomer (1) (27.0 parts), and water (84.0 parts) and a mixture 2 containing L-ascorbic acid (0.3 parts), 2-mercaptopropionic acid (1.4 parts), and water (28.4 parts) were simultaneously added dropwise from separate nozzles. The addition was carried out continuously at a constant rate, with the mixture 1 being added dropwise over 150 minutes and the mixture 2 being added dropwise over 210 minutes. After the dropwise addition of the mixed solution 2 was completed, the reaction vessel was maintained at 60° C. for an additional 60 minutes to complete the polymerization reaction, thereby obtaining a polymer (12) of the present disclosure.
[0091] Comparative Example 1 A glass reaction vessel equipped with a thermometer, a stirrer (paddle blade), a dropping funnel, a nitrogen inlet tube, and a reflux condenser was charged with 85.7 parts of water, and the atmosphere inside the reaction vessel was replaced with nitrogen while stirring. The temperature was raised to 60°C under a nitrogen atmosphere, and then 4.2 parts of 35% hydrogen peroxide solution was added to the reaction vessel. After the temperature stabilized at 60°C, Mixed Solution 1, which was a mixture of AA (144.0 parts), 40% HAPS (75.0 parts), monomer (1) (9.0 parts), and water (52.0 parts), and Mixed Solution 2, which was a mixture of L-ascorbic acid (0.4 parts), 2-mercaptopropionic acid (3.5 parts), and water (26.1 parts), were simultaneously added dropwise from separate nozzles. The addition was carried out continuously at a constant rate, with Mixed Solution 1 being added dropwise in its entirety over 150 minutes and Mixed Solution 2 being added dropwise in its entirety over 210 minutes. After the dropwise addition of Mixture 2 was completed, the reaction vessel was maintained at 60° C. for an additional 60 minutes to complete the polymerization reaction, thereby obtaining Comparative Polymer (1) of the present disclosure.
[0092] <Comparative Example 2> IPN-50 (158.6 parts), AA (0.3 parts), and water (89.3 parts) were charged into a glass reaction vessel equipped with a thermometer, a stirrer (paddle blade), a dropping funnel, a nitrogen inlet tube, and a reflux condenser. The atmosphere inside the reaction vessel was replaced with nitrogen while stirring, and the temperature was raised to 60 ° C. under a nitrogen atmosphere. 0.7 parts of 35% hydrogen peroxide solution was then added to the reaction vessel. After the temperature stabilized at 60 ° C., mixed solution 1, which was a mixture of AA (21.1 parts) and water (100.0 parts), and mixed solution 2, which was a mixture of L-ascorbic acid (0.1 parts), 2-mercaptopropionic acid (1.0 parts), and water (29.0 parts), were simultaneously added dropwise from separate nozzles. The addition was carried out continuously at a constant rate, with mixed solution 1 being added dropwise over 150 minutes and mixed solution 2 being added dropwise over 210 minutes. After the dropwise addition of Mixture 2 was completed, the reaction vessel was maintained at 60° C. for an additional 60 minutes to complete the polymerization reaction, thereby obtaining Comparative Polymer (2) of the present disclosure.
[0093] <Comparative Example 3> 186.4 parts of water was charged into a glass reaction vessel equipped with a thermometer, a stirrer (paddle blade), a dropping funnel, a nitrogen inlet tube, and a reflux condenser, and the temperature was raised to the boiling point reflux temperature. Then, under stirring, a mixture (459.1 parts) of 37% aqueous sodium acrylate solution (445.1 parts) and acrylic acid (14.0 parts), 25% HAPS (299.5 parts), 20% NaPS (33.7 parts), and 12.5% aqueous hydrogen peroxide solution (18.3 parts) were added dropwise at a constant rate, respectively, over 120 minutes for the mixture of aqueous sodium acrylate solution and aqueous acrylic acid solution, 120 minutes for the 25% HAPS, 140 minutes for the 20% NaPS, and 120 minutes for the 12.5% aqueous hydrogen peroxide solution. After the dropwise addition was completed, the boiling point reflux temperature was maintained for 30 minutes to complete the polymerization. In this way, a comparative polymer (3) was obtained.
[0094] The copolymers obtained in Examples 1 to 12 and Comparative Examples 1 to 3 were evaluated for their ability to inhibit magnesium silicate formation and their ability to inhibit silica polymer formation by the methods described above. The results are shown in Tables 1 and 2. In Tables 1 and 2, the monomer compositions are listed in the weight ratio of structural unit (a) / structural unit (b) / structural unit (c) / structural unit (d) in that order.
[0095]
[0096]
[0097] As a result of the above evaluation, it was revealed that the polymers of Examples 1 to 12 having the structural units (a) to (d) have excellent ability to inhibit the deposition of both magnesium silicate and silica polymer. In Comparative Example 2, in the magnesium silicate formation inhibition test, even when 90 ppm of comparative polymer (2) was added, SiO ２ The concentration of 200 ppm could not be maintained.
Claims
1. A polymerizable composition comprising a structural unit (a) derived from an unsaturated carboxylic acid monomer (A), a structural unit (b) derived from a sulfonic acid group-containing monomer (B), and a polymerizable compound represented by the following formula (1): 【Chemical 1】 (In the formula, R １ , R ２ and R ３ are the same or different and represent a hydrogen atom or a methyl group. ４ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. (R ５ O) are the same or different and represent an oxyalkylene group having 2 to 18 carbon atoms. n represents the average number of moles of oxyalkylene groups added and is a number from 5 to 300. x1 represents a number from 0 to 4. y1 represents 0 or 1. The copolymer has a structural unit (c) derived from a polyalkylene glycol monomer (C) represented by the formula (I) and a structural unit (d) derived from a hydrophobic monomer (D), the content of the structural unit (a) is 15 to 95% by mass relative to 100% by mass of all structural units; the content of the structural unit (b) is 1 to 20% by mass relative to 100% by mass of all structural units; A polycarboxylic acid copolymer having a weight average molecular weight of 10,000 to 200,000.
2. The polycarboxylic acid copolymer according to claim 1 , wherein the hydrophobic monomer (D) is a monomer represented by the following formula (2): 【Chemistry 2】 (In the formula, R ６ , R ７ and R ８ are the same or different and represent a hydrogen atom or a methyl group. x2 represents a number from 0 to 4. y2 represents 0 or 1. Z represents a hydrocarbon group having 4 to 18 carbon atoms or a group represented by the following formula (3): 【Chemistry 3】 (In the formula, X １ , Y １ represents a hydroxyl group or a group represented by the following formula (4) or (5), and X １ , Y １ One of the groups represents a hydroxyl group, and the other represents a group represented by the following formula (4) or (5): 【Chemistry 4】 (In the formula, R ９ are the same or different and represent an alkylene group having 2 to 4 carbon atoms. m is an oxyalkylene group (—O—R ９ -) and represents a number from 0 to 5. １０ represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms. １１ , R １２ are the same or different and represent an alkyl group having 1 to 18 carbon atoms. １１ , R １２ The total number of carbon atoms is 4 or more.
3. 3. The polycarboxylic acid copolymer according to claim 1, wherein the content of the structural unit (c) is 10 to 70% by mass relative to 100% by mass of all structural units.
4. 3. The polycarboxylic acid copolymer according to claim 1, wherein the content of the structural unit (d) is 0.1 to 20% by mass relative to 100% by mass of all structural units.
5. The polycarboxylic acid copolymer according to claim 1 or 2, wherein the polycarboxylic acid copolymer may have a structural unit (e) derived from a monomer (E) other than the unsaturated carboxylic acid monomer (A), the sulfonic acid group-containing monomer (B), the polyalkylene glycol monomer (C) and the hydrophobic monomer (D), and the proportion of the structural unit (e) is 0 to 30 mass% relative to 100 mass% of all structural units.
6. A water treatment agent containing a polycarboxylic acid copolymer, The polycarboxylic acid copolymer comprises a structural unit (a) derived from an unsaturated carboxylic acid monomer (A), a structural unit (b) derived from a sulfonic acid group-containing monomer (B), and a copolymer represented by the following formula (1): 【Chemistry 5】 (In the formula, R １ , R ２ and R ３ are the same or different and represent a hydrogen atom or a methyl group. ４ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. (R ５ O) are the same or different and represent an oxyalkylene group having 2 to 18 carbon atoms. n represents the average number of moles of oxyalkylene groups added and is a number from 5 to 300. x1 represents a number from 0 to 4. y1 represents 0 or 1. The copolymer has a structural unit (c) derived from a polyalkylene glycol monomer (C) represented by the formula (I) and a structural unit (d) derived from a hydrophobic monomer (D), the content of the structural unit (a) is 15 to 95% by mass relative to 100% by mass of all structural units; the content of the structural unit (b) is 1 to 20% by mass relative to 100% by mass of all structural units; A water treatment agent having a weight average molecular weight of 10,000 to 200,000.
7. A silica scale inhibitor comprising a polycarboxylic acid copolymer, The polycarboxylic acid copolymer comprises a structural unit (a) derived from an unsaturated carboxylic acid monomer (A), a structural unit (b) derived from a sulfonic acid group-containing monomer (B), and a copolymer represented by the following formula (1): 【Chemistry 6】 (wherein R 1 , R 2 and R 3 are the same or different and represent a hydrogen atom or a methyl group; R 4 is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms; (R 5 O) are the same or different and represent an oxyalkylene group having 2 to 18 carbon atoms; n is the average number of moles of oxyalkylene groups added and is a number from 5 to 300; x1 is a number from 0 to 4; and y1 is 0 or 1), and has a structural unit (c) derived from a polyalkylene glycol monomer (C) represented by the formula: the content of the structural unit (a) is 15 to 95% by mass relative to 100% by mass of all structural units; the content of the structural unit (b) is 1 to 20% by mass relative to 100% by mass of all structural units; A silica scale inhibitor having a weight average molecular weight of 10,000 to 200,000.