JP7053297B2 - A polycarboxylic acid-based copolymer and a method for producing the same, and an additive and cement composition for inorganic particles using the same. - Google Patents

Description

The present invention relates to a polycarboxylic acid-based copolymer and a method for producing the same, and an additive for inorganic particles and a cement composition using the same.

Living polymerization is a polymerization capable of synthesizing a polymer whose structure is controlled, and has the following characteristics (see Non-Patent Document 1).
1. 1. When the polymerization reaction is started, the polymerization proceeds until the monomer has a certain concentration or less.
2. 2. The number average molecular weight increases in proportion to the polymerization rate.
3. 3. The number of polymer molecules (active species) is constant and is not related to the polymerization rate.
4. The molecular weight is stoichiometrically controlled.
5. A polymer having a molecular weight distribution narrower than that of a normal polymerization reaction can be obtained.
6. Subsequent addition of the monomer allows the polymerization reaction to proceed again, and a block copolymer can also be obtained.
7. The end of the polymer chain can be modified in quantitative yield.

As living radical polymerization, reversible addition-fragmentation chain transfer (RAFT) polymerization (see Patent Document 1), MADIX (macro-molecullar designin via interchange of RP) polymerization (see RP xanthates) Atom transfer radical polymerization (see Non-Patent Document 2), NMP (nitroxide-mediated polymerization) (see Patent Document 3), TERP (organotropic-mediated living) Here, since MADIX polymerization has the same reversible chain transfer mechanism as RAFT polymerization, the name "RAFT polymerization" is used uniformly in the present specification.

ATRP is a catalytic reaction by a transition metal complex, and the polymerization proceeds while the transition metal takes two different oxidation states. It is common to use an alkyl halide as an initiator. As the transition metal of the transition metal complex, Ti, Fe, Co, Ni, Cu, Mo, Ru, Rh, Pd, Re, Os and the like can be used, but the method using Cu is the most common. For example, examples of the transition metal complex having Cu as its nucleus include a catalyst composed of Cu and a nitrogen-containing ligand. Cu takes two types of oxidation states, Cu ¹⁺ and Cu ²⁺ . The drawbacks of ATRP are the use of unstable alkyl halides in the air and the use of large amounts of catalyst, and the purification process to remove the catalyst and the generation of waste increase the production cost of the polymer. ..

NMP requires a combination of radical initiators, monomers, and nitroxide radicals that trap intermediate polymer radical species. The difficulty with NMP lies in the difficulty of synthesizing a general-purpose initiator capable of supplying both a reactive radical that initiates polymerization and a stable nitroxide radical from a single molecule. In that respect, NMP has the lowest versatility.

TERP is a polymerization method using an organic tellurium compound, and is based on an equilibrium reaction between a dormant reaction species called a dormant species and an active species. Since an organic metal is used, an atmosphere of complete dehydration is required and care must be taken in handling.

In RAFT polymerization, in the presence of a suitable chain transfer agent (RAFT agent), reactions related to RAFT equilibrium are added to the general free radical polymerization of substituted monomers. The advantages of RAFT polymerization are that it can control the polymerization reaction of most of the monomers that can be polymerized by radical polymerization, and that unprotected functional groups in the monomers and solvents (eg, -OH, -NR ₂ , -COOH, -CONR). _2. Highly tolerant to -SO _3H ), polymerizable in water or radical solvents, wide range of reaction conditions applicable, easy to use and inexpensive compared to competing technologies. Can be mentioned.

Examples of the RAFT agent include dithioesters (-(C = S) -S-, see Patent Document 1), dithiocarbamate (> N- (C = S) -S-, see Patent Document 4), and trithio. Thiocarbonyls of carbonates (-S- (C = S) -S-, see Patent Documents 5 and 6), xanthates (-O- (C = S) -S-, see Patent Documents 4 and 7) and the like. Examples thereof include compounds having a thio group (-(C = S) -S-), and the living property is exhibited by a reversible chain transfer reaction.

RAFT agents typically establish an equilibrium state consisting of a very small amount of growth radicals and a dormant species (a polymer having a thiocarbonylthio group at the end) that accounts for most of the growth radicals in the presence of a radical polymerization initiator. (See Non-Patent Document 4).

It has recently been reported that RAFT polymerization using a specific monomer called butenylalkylene polyoxyethylene polyoxypropylene ether (BAPP) can synthesize a polycarboxylic acid-based copolymer that can be used as an additive for cement (non-). See Patent Document 5).

However, since the polycarboxylic acid-based copolymer described in Non-Patent Document 5 has high hydrophobicity of the copolymer due to the alkylene portion of BAPP, cement particles are aggregated by hydrophobic association to increase the viscosity of the cement composition. The suitability for cement additives remains questionable in that it raises the price.

In general, in order for the polycarboxylic acid-based copolymer to sufficiently function as an additive for cement, the amount of the polycarboxylic acid-based copolymer used to achieve the desired fluidity in the case of a cement composition. It is important to be able to reduce as much as possible.

Japanese Patent Publication No. 2000-515181 Japanese Patent Publication No. 2002-512653 U.S. Patent No. 4581429 Special Table 2002-508409 Publication No. Special Table 2003-522816 Japanese Patent Publication No. 2008-508384 Japanese Patent Publication No. 2002-512653

Roderic P. Quirk and Bumjae Lee, Experimental Criteria for Living Polymerizations, Polymer International 27 (1992) 359-376. M. Kato, M.M. Kamigaito, M.M. Sawamoto, and T. et al. Higashimura, Macromolecules 28 (1995) 1721-1723. Shigeru Yamako, Yasuyuki Nakamura, Living Radical Polymerization 2. Polymerization mechanism and method 2, Japan Rubber Association Paper, 82 (2009) 363-369. A. Fabier, M.M. -T. Charreyre, Experimental Requests for an Effect Control of Free-Radical Polymerizations via the Reversible Addition-Frashible Addition-Frashible Addition-FragmentRasis Binbin Yu, Zhong Zeng, Qinyu Ren, Yang Chen, Mei Liang, Huawei Zou, Journal of Molecular Structure 1120 (2016) 171-179.

An object of the present invention is to use an additive for inorganic particles (additive for cement), which can achieve a desired fluidity even when the amount added to the cement composition is reduced, and the above-mentioned additive. It is an object of the present invention to provide a possible polycarboxylic acid-based copolymer and a method for producing the polycarboxylic acid-based copolymer. Another object of the present invention is to provide a cement composition containing the additive for inorganic particles (additive for cement).

The polycarboxylic acid-based copolymer according to one embodiment of the present invention has the structural unit (I) derived from the unsaturated polyalkylene glycol-based monomer (a) represented by the following general formula (1) and the following general formula. It has a structural unit (II) derived from the unsaturated carboxylic acid-based monomer (b) represented by (2).

In the general formula (1), R ¹ and R ² represent the same or different hydrogen atom or methyl group, R ³ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and AO represents a hydrocarbon group. Represents an oxyalkylene group having 2 to 18 carbon atoms, n represents the average number of moles of the oxyalkylene group represented by AO, n is an integer of 1 to 500, and x is an integer of 0 to 2. be.

In the general formula ( ² ), ^R4 to R6 represent the same or different hydrogen atom, methyl group, or-(CH2) _zCOOM group, and-( _CH2 ) _zCOOM group is -COOX group or other. -(CH ₂ ) _z COM group may form an anhydride, z is an integer of 0 to 2, and M is a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, and an organic ammonium group. , Or an organic amine group, where X represents a hydrogen atom, a methyl group, an ethyl group, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group.

The polycarboxylic acid-based copolymer according to this embodiment is characterized in that it has a structure represented by the following general formula (3).

In the general formula (3), Z ⁴ is a substituted or unsubstituted linear, branched or cyclic alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted phenyl group .

In one embodiment, Z ⁴ in the general formula (3) is a —CH ₂ COM group (M is a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group. Represented) or a substituted or unsubstituted phenyl group.

In one embodiment, Z ⁴ in the general formula (3) is a —CH ₂ COOH group.

In one embodiment, the weight average molecular weight (Mw) in terms of polyethylene glycol obtained by gel permeation chromatography (GPC) of the polycarboxylic acid-based copolymer is in the range of 500 to 100,000, and the degree of dispersion (dispersity). Mw / Mn) is 1.0 to 1.8.

In one embodiment, ^R2 in the general formula (1) is a methyl group.

According to another embodiment of the present invention, an additive for inorganic particles containing the above polycarboxylic acid-based copolymer is provided.

According to still another embodiment of the present invention, there is provided a cement composition containing the above polycarboxylic acid-based copolymer.

According to another embodiment of the present invention, the unsaturated polyalkylene glycol-based monomer (a) represented by the general formula (1) and the unsaturated carboxylic acid-based monomer represented by the general formula (2). Provided is a method for producing a polycarboxylic acid-based copolymer, which comprises a polymerization step of polymerizing a monomer component essentially containing a weight (b). The production method is characterized in that the polymerization step is carried out in the presence of the trithiocarbonate type compound represented by the following general formula (4).

In general formula (4), Z ¹ and Z ² represent organic residues, and Z ¹ and Z ² are not identical to each other.

In one embodiment, the trithiocarbonate type compound has a structure represented by the following general formula (5).

In the general formula (5), Z ⁴ is a substituted or unsubstituted linear, branched or cyclic alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted phenyl group , and R ⁴¹ is an atom. Alternatively, it represents an atomic group, and R ⁴² and R ⁴³ represent an atom or an atomic group excluding a hydrogen atom independently of each other.

In one embodiment, Z ⁴ in the general formula (5) is a —CH ₂ COM group (M is a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group. Represented) or a substituted or unsubstituted phenyl group.

In one embodiment, Z ⁴ in the general formula (5) represents a -CH ₂ COM group (M represents a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group. ) Or a substituted or unsubstituted phenyl group, R ⁴¹ is a hydrogen atom, R ⁴² is a substituted or unsubstituted linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, and R ⁴³ is a —COM group (M represents a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group).

According to the present invention, it can be used as an additive for inorganic particles (additive for cement), which can achieve a desired fluidity even when the amount added to the cement composition is reduced, and the above-mentioned additive. It is possible to provide a polycarboxylic acid-based copolymer capable and a method for producing the polycarboxylic acid-based copolymer. Further, according to the present invention, it is possible to provide a cement composition containing the additive for inorganic particles (additive for cement).

It is explanatory drawing which shows how to draw a baseline in a GPC chart. It is a chart which shows an example of the result of having measured the UV spectrum for confirming that a polycarboxylic acid-based copolymer has a structure (trithiocarbonate structure) represented by the general formula (3).

In the present specification, the expression "(meth) acrylic" means "acrylic and / or methacrolein", and the expression "(meth) acrylate" means "acrylate and / or methacrylate". When the expression "(meth) allyl" is used, it means "allyl and / or methacrolein", and when the expression "(meth) acrolein" is used, "acrolein and / or methacrolein" is used. It means "rain". Further, when the expression "acid (salt)" is used in the present specification, it means "acid and / or a salt thereof". Further, when the expression "mass" is used in the present specification, it may be read as "weight" which is generally used as a unit of weight in the present specification, and conversely, "weight" is used in the present specification. When there is an expression of, it may be read as "mass" which is commonly used as an SI system unit indicating weight.

<< Polycarboxylic acid-based copolymer >>
The polycarboxylic acid-based copolymer according to one embodiment of the present invention has a structural unit (I) derived from the unsaturated polyalkylene glycol-based monomer (a) represented by the general formula (1) and a general formula (2). It has a structural unit (II) derived from the unsaturated carboxylic acid-based monomer (b) represented by).

The structural unit (I) derived from the unsaturated polyalkylene glycol-based monomer (a) represented by the general formula (1) is specifically represented by the following formula.

Further, the structural unit (II) derived from the unsaturated carboxylic acid-based monomer (b) represented by the general formula (2) is specifically represented by the following formula.

In the general formula (1) and the general formula (I), R ¹ and R ² represent the same or different hydrogen atoms or methyl groups.

In the general formula (1) and the general formula (I), ^R2 is preferably a methyl group. Since ^R2 is a methyl group, the effects of the present invention can be more exhibited.

In the general formula (1) and the general formula (I), R ³ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. Examples of the hydrocarbon group having 1 to 30 carbon atoms include an alkyl group having 1 to 30 carbon atoms (aliphatic alkyl group and an alicyclic alkyl group), an alkenyl group having 1 to 30 carbon atoms, and a carbon atom number. Examples thereof include an alkynyl group having 1 to 30 and an aromatic group having 6 to 30 carbon atoms. In terms of further exhibiting the effects of the present invention ^, R3 is preferably a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and more preferably a hydrogen atom or a hydrocarbon having 1 to 12 carbon atoms. It is a hydrogen group, more preferably a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and particularly preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In the general formula (1) and the general formula (I), AO is an oxyalkylene group having 2 to 18 carbon atoms, preferably an oxyalkylene group having 2 to 8 carbon atoms, and more preferably a carbon atom number. It is an oxyalkylene group of 2 to 4. When the AO is any two or more types selected from an oxyethylene group, an oxypropylene group, an oxybutylene group, etc., the addition form of AO is any of random addition, block addition, alternate addition, and the like. May be. In order to secure a balance between hydrophilicity and hydrophobicity, it is preferable that the oxyalkylene group contains an oxyethylene group as an essential component, and 50 mol% or more of the total oxyalkylene group is an oxyethylene group. It is preferable that 90 mol% or more of the total oxyalkylene group is an oxyethylene group.

In the general formula (1) and the general formula (I), n represents the average number of moles of oxyalkylene group represented by AO, and is a number of 1 to 500, preferably a number of 2 to 200. The number is more preferably 5 to 200, still more preferably 8 to 100, particularly preferably 20 to 70, and most preferably 40 to 60. When n is within the above range, it is possible to provide an additive for cement that can reduce the amount used to achieve the desired fluidity when the cement composition is obtained.

In the general formula (1) and the general formula (I), x is an integer of 0 to 2.

Examples of the unsaturated polyalkylene glycol-based monomer (a) represented by the general formula (1) include hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, (meth) allyl alcohol, and 3-methyl-3-. Butene-1-ol, 3-methyl-2-butene-1-ol, 2-methyl-3-butene-2-ol, 2-methyl-2-butene-1-ol, 2-methyl-3-butene- Examples thereof include compounds in which 1 to 500 mol of alkylene oxide is added to any of 1-ol. The unsaturated polyalkylene glycol-based monomer (a) is preferably a compound in which 1 to 500 mol of alkylene oxide is added to 3-methyl-3-butene-1-ol, or 1 to 1 to alkylene oxide is added to metallic alcohol. It is a compound to which 500 mol is added.

The unsaturated polyalkylene glycol-based monomer (a) represented by the general formula (1) may be of only one type or of two or more types.

In the general formula (2) and the general formula (II), R ⁴ to R ⁶ represent the same or different hydrogen atom, methyl group, or-(CH ₂ ) _z COM group. -The (CH ₂ ) _z COM group may form anhydrate with the -COOX group or other- (CH ₂ ) _z COM groups. z is an integer of 0 to 2.

M represents a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group. Here, examples of the alkali metal include lithium, sodium, potassium and the like. Examples of alkaline earth metals include calcium and magnesium.

Further, examples of the organic ammonium salt include methylammonium salt, ethylammonium salt, dimethylammonium salt, diethylammonium salt, trimethylammonium salt, triethylammonium salt and the like. Examples of the organic amine constituting the organic amine salt include monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, hydroxyethyldiisopropanolamine, dihydroxyethylisopropanolamine, and tetrakis (dihydroxyethylisopropanolamine). Examples thereof include alkanolamines such as 2-hydroxypropyl) ethylenediamine and pentakis (2-hydroxypropyl) diethylenetriamine. Among these, diisopropanolamine, triisopropanolamine, hydroxyethyldiisopropanolamine, tetrakis (2-hydroxypropyl) ethylenediamine, pentax (2-hydroxypropyl) diethylenetriamine are preferable, and triisopropanolamine and hydroxy are more preferable. It is ethyldiisopropanolamine.

X represents a hydrogen atom, a methyl group, an ethyl group, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group. Examples of organic amines constituting alkali metals, alkaline earth metals, organic ammonium groups and organic amine groups as X are given in the definitions of ^R4 to R6 in the general formulas ( ² ) and (II). (CH ₂ ) “M” in the _z COMM group is the same as illustrated above.

Examples of the unsaturated carboxylic acid-based monomer (b) represented by the general formula (2) include monocarboxylic acid-based monomers such as (meth) acrylic acid and crotonic acid, or salts thereof; maleic acid, Dicarboxylic acid-based monomers such as itaconic acid and fumaric acid or salts thereof; anhydrides of dicarboxylic acid-based monomers such as maleic acid, itaconic acid and fumaric acid or salts thereof; and the like. Examples of the salt here include alkali metal salts, alkaline earth metal salts, ammonium salts, organic ammonium salts, and organic amine salts. These salts correspond to the case where X in the general formula (2) represents an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, and an organic amine group, respectively.

The unsaturated carboxylic acid-based monomer (b) represented by the general formula (2) is preferably (meth) acrylic acid, maleic acid, or maleic anhydride in that the effects of the present invention can be further exhibited. It is more preferably acrylic acid or methacrylic acid.

The unsaturated carboxylic acid-based monomer (b) represented by the general formula (2) may be of only one type or of two or more types.

The content ratio of the structural unit (I) in the polycarboxylic acid-based copolymer is preferably 30% by mass to 99% by mass, more preferably 40% by mass to 95% by mass, and further preferably 50% by mass. % To 90% by mass, particularly preferably 60% by mass to 85% by mass, and most preferably 70% by mass to 80% by mass. When the content ratio of the structural unit (I) in the polycarboxylic acid-based copolymer is within the above range, the amount used for achieving the desired fluidity in the cement composition can be further reduced, for cement. Additives can be provided.

The content ratio of the structural unit (II) in the polycarboxylic acid-based copolymer is preferably 1% by mass to 70% by mass, more preferably 5% by mass to 60% by mass, and further preferably 10% by mass. % To 50% by mass, particularly preferably 15% by mass to 40% by mass, and most preferably 20% by mass to 30% by mass. When the content ratio of the structural unit (II) in the polycarboxylic acid-based copolymer is within the above range, the amount used for achieving the desired fluidity in the cement composition can be further reduced, for cement. Additives can be provided.

The total content of the structural unit (I) and the structural unit (II) in the polycarboxylic acid-based copolymer is preferably 50% by mass to 100% by mass, and more preferably 70% by mass to 100% by mass. %, More preferably 90% by mass to 100% by mass, particularly preferably 95% by mass to 100% by mass, and most preferably substantially 100% by mass. When the total content ratio of the structural unit (I) and the structural unit (II) in the polycarboxylic acid-based copolymer is within the above range, the desired fluidity can be achieved in the case of a cement composition. It is possible to provide an additive for cement that can further reduce the amount used.

The polycarboxylic acid-based copolymer may contain a structural unit (III) derived from another monomer (c) in addition to the structural unit (I) and the structural unit (II).

The monomer (c) is a monomer copolymerizable with the monomer (a) and the monomer (b). The monomer (c) may be only one kind or two or more kinds.

Examples of the monomer (c) include hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate; unsaturated monos such as methyl (meth) acrylate and glycidyl (meth) acrylate. Esters of carboxylic acids and alcohols with 1 to 30 carbon atoms; various (alkoxy) (poly) alkylene glycol mono (meth) such as polyethylene glycol mono (meth) acrylate and methoxy (poly) ethylene glycol mono (meth) acrylate. Glycols; Half esters of unsaturated dicarboxylic acids such as (anhydrous) maleic acid, fumaric acid, and itaconic acid and alcohols having 1 to 30 carbon atoms; unsaturated (anhydrous) maleic acid, fumaric acid, itaconic acid, etc. Diesters of dicarboxylic acids and alcohols having 1 to 30 carbon atoms; halfamides of the unsaturated dicarboxylic acids and amines having 1 to 30 carbon atoms; the unsaturated dicarboxylic acids and amines having 1 to 30 carbon atoms. Diamides with the above; half esters of alkyl (poly) alkylene glycols obtained by adding 1 to 500 mol of alkylene oxides having 2 to 18 carbon atoms to the above alcohols and amines and the above unsaturated dicarboxylic acids; Diesters of an alkyl (poly) alkylene glycol supplemented with 1 to 500 mol of an alkylene oxide having 2 to 18 carbon atoms and the unsaturated dicarboxylic acids; the unsaturated dicarboxylic acids and the glycol having 2 to 18 carbon atoms or these. Half-esters with polyalkylene glycols having an added mole number of 2 to 500; the unsaturated dicarboxylic acids and glycols having 2 to 18 carbon atoms or polyalkylene glycols having an added mole number of 2 to 500 of these glycols. Diesters; half-amides of maleamic acid and glycols with 2 to 18 carbon atoms or polyalkylene glycols with an additional molar number of 2 to 500 of these glycols; (poly) ethylene glycol di (meth) acrylate, (poly) propylene. (Poly) alkylene glycol di (meth) acrylates such as glycol di (meth) acrylate; Polyfunctional (meth) acrylates such as hexanediol di (meth) acrylate and trimethylolpropantri (meth) acrylate; polyethylene glycol dimalate Etc. (Poly) alkylene glycol dimalates; vinyl sulfonate, (meth) ants Unsaturated sulfonic acids (salts) such as lesulfonate, 2-methylpropanesulfonic acid (meth) acrylamide, styrenesulfonic acid; unsaturated monocarboxylic acids such as methyl (meth) acrylamide and amines with 1 to 30 carbon atoms. Amides; Vinyl aromatics such as styrene, α-methylstyrene and vinyltoluene; Alcandiol mono (meth) acrylates such as 1,4-butanediol mono (meth) acrylate; Dienes such as butadiene and isoprene; Unsaturated amides such as (meth) acrylic (alkyl) amides, N-methylol (meth) acrylamides, N, N-dimethyl (meth) acrylamides; unsaturated cyanides such as (meth) acrylonitrile; unsaturateds such as vinyl acetate. Esters; Unsaturated amines such as aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, vinylpyridine; Divinyl aromatics such as divinylbenzene; (meth) allyl alcohol, glycidyl (meth) allyl ether And the like; vinyl ethers such as (methoxy) polyethylene glycol monovinyl ether; (meth) allyl ethers such as (methoxy) polyethylene glycol mono (meth) allyl ether; and the like.

The content ratio of the structural unit (III) in the polycarboxylic acid-based copolymer is preferably 0% by mass to 50% by mass, more preferably 0% by mass to 40% by mass, and further preferably 0% by mass. % To 30% by mass, particularly preferably 0% by mass to 20% by mass, and most preferably 0% by mass to 10% by mass. When the content ratio of the structural unit (III) in the polycarboxylic acid-based copolymer is within the above range, the amount used for achieving the desired fluidity in the cement composition can be further reduced, for cement. Additives can be provided.

The content ratio of the structural unit (I), the content ratio of the structural unit (II), the total content ratio of the structural unit (I) and the structural unit (II) in the polycarboxylic acid-based copolymer, the polycarboxylic acid-based The content ratio of the structural unit (III) in the copolymer can be known, for example, by various structural analyzes (for example, NMR) of the polycarboxylic acid-based copolymer. Further, if the amount of various monomers used in producing the polycarboxylic acid-based copolymer is known without performing various structural analyzes as described above, LC (liquid chromatography) is used. ), The consumption rate of the monomer in the polymerization reaction is analyzed, and the structural unit (I) in the polycarboxylic acid-based copolymer is assumed that all the consumed monomers are converted into the copolymer by the polymerization reaction. ), The content ratio of the structural unit (II), the total content ratio of the structural unit (I) and the structural unit (II), the content ratio of the structural unit (III) in the polycarboxylic acid-based copolymer, etc. May be calculated.

When the content ratio of the structural unit in the polycarboxylic acid-based copolymer is determined, when the structural unit has a salt of a carboxyl group, all the acid portions of the carboxyl group are converted into sodium salts for calculation.

The polyethylene glycol-equivalent weight average molecular weight (Mw) obtained by gel permeation chromatography (GPC) of the polycarboxylic acid-based copolymer is preferably 500 to 100,000, more preferably 3000 to 70,000, and further. It is preferably 5000 to 40,000, particularly preferably 7500 to 35,000, and most preferably 10,000 to 30,000. If the weight average molecular weight (Mw) in terms of polyethylene glycol obtained by gel permeation chromatography (GPC) of the polycarboxylic acid-based copolymer is within the above range, the desired fluidity can be obtained in the case of a cement composition. It is possible to provide a polycarboxylic acid-based copolymer that can further reduce the amount used to achieve this.

The dispersity (Mw / Mn) of the polycarboxylic acid-based copolymer is preferably 1.0 to 1.8, more preferably 1.0 to 1.6, and even more preferably 1.0 to 1. It is 0.4, particularly preferably 1.0 to 1.3, and most preferably 1.0 to 1.2. If the dispersity (Mw / Mn) is very narrow as described above, the amount used to achieve the desired fluidity in the cement composition can be further reduced, and the polycarboxylic acid-based copolymer can be used. Can be provided.

As described above, the polycarboxylic acid-based copolymer according to this embodiment is characterized in that it has a structure (trithiocarbonate structure) represented by the following general formula (3). By essentially containing such a trithiocarbonate structure, the polycarboxylic acid-based copolymer according to the present embodiment further reduces the amount used to achieve the desired fluidity when made into a cement composition. It is possible to provide a polycarboxylic acid-based copolymer capable of this.

In the general formula (3), Z ⁴ is a substituted or unsubstituted linear, branched or cyclic alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted phenyl group . Examples of such an alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group and a hexyl group. Heptyl group, octyl group, 2-ethylhexyl group, isooctyl group, nonyl group, 2,3,5-trimethylhexyl group, decyl group, undecyl group, 4-ethyl-5-methyloctyl group, dodecyl group, tridecyl group, tetradecyl A linear or branched alkyl group such as a group, a pentadecyl group, a hexadecyl group, a heptadecyl group or an octadecyl group; and a cyclic alkyl group (cycloalkyl group) such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group or a cyclohexyl group. Can be mentioned. Of these alkyl groups, the undecylic group is particularly preferable.

The alkyl group may be substituted. When the alkyl group is substituted, the substituents that can replace the alkyl group include an alkoxy group, an aryl group, a heteroaryl group, a halogeno group, a hydroxy group, a carboxy group, a cyano group, a nitro group and an amino group. , Thiosianate group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, sulfo group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group and the like. A particularly preferred substituent when the alkyl group is substituted is a carboxy group. At this time, it is particularly preferable that the alkyl group as Z ⁴ is a methyl group.

That is, in one preferred embodiment, Z ⁴ in the general formula (3) is a —CH ₂ COM group (M is a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine. A group) or a substituted or unsubstituted phenyl group. Further, in a more preferable embodiment, Z ⁴ in the general formula (3) is a —CH ₂ COOM group, and in a particularly preferable embodiment, Z ⁴ in the general formula (3) is a —CH ₂ COOH group. In addition, an example of an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group as "M" when Z ⁴ in the general formula (3) is a -CH ₂ COM group is a general formula. (2) and the "M" in the-(CH ₂ ) _z COMM group in the definition of ^R4 to R6 in the general ^formula (II) are the same as exemplified above.

Specific examples of the trithiocarbonate structure represented by the general formula (3) include, but are not limited to, those represented by the following chemical formulas (6) to (13). Above all, it is preferable to have a trithiocarbonate structure represented by the chemical formula (7) from the viewpoint that the effect of the present invention can be more effectively expressed.

The form in which the polycarboxylic acid-based polymer according to the present embodiment has the structure (trithiocarbonate structure) represented by the above-mentioned general formula (3) is not particularly limited, but in a preferred embodiment, the above-mentioned common weight is used. The coalescence has a structure (trithiocarbonate structure) represented by the general formula (3) as the terminal structure of the polymer main chain.

The fact that the polycarboxylic acid-based copolymer has the structure (trithiocarbonate structure) represented by the above-mentioned general formula (3) is comprehensively determined by various structural analyzes of the following (i) to (iii). It is possible to confirm.
(I) ³³ Method using S-NMR:
First, using a separation means such as preparative gel permeation chromatography (GPC), only the copolymer is isolated from the composition containing the copolymer to be analyzed. Then, by measuring ³³ S-NMR of the isolated copolymer, it is possible to confirm the existence of the trithiocarbonate structure (-SC (= S) -S-). For the method of utilizing this ³³ S-NMR, refer to the literature (Yoshio Kosugi, Sulfur-33 Nuclear NMR of Benzenesulfonic Acid, Oil Chemistry Bulletin Vol. 38, No. 7, pp. 570-571 (1989)). obtain.
(Ii) Method using mass spectrometry:
First, in the same manner as described above, using a separation means such as preparative GPC, only the copolymer is isolated from the composition containing the copolymer to be analyzed. Then, mass spectrometry is performed on the isolated copolymer. At this time, as the ionization method, an ESI (electrospray ionization) method, a MALDI (matrix-assisted laser desorption ionization) method, or the like can be used. Then, MS / MS measurement (precision mass spectrometry) can be used for mass spectrometry. That is, the first mass separator (MS1) selects a specific ion containing the trithiocarbonate structure and then collides with the inert gas in the subsequent collision cell to cause fragmentation. Then, the fragment ion (including the trithiocarbonate structure) thus generated can be separated by a second mass separation unit (MS2) and detected (product ion spectrum).
(Iii) How to use UV spectrum:
First, a GPC equipped with a PDA detector and an RI detector is used to measure the UV spectrum of the copolymer in a solution containing the copolymer. Although slightly different depending on the structure of the RAFT agent, it is generally known that a compound having a trithiocarbonate structure has weak UV absorption in the vicinity of 210 nm to 250 nm and in the vicinity of 290 nm to 350 nm. Therefore, a copolymer polymerized using a RAFT agent having a trithiocarbonate structure and a copolymer having the same monomer composition and polymerized using a chain transfer agent such as mercaptopropionic acid without using the RAFT agent. Comparing the UV spectra at the peak top elution time of each copolymer component, the former has a higher intensity of UV absorption in the vicinity of 210 nm to 250 nm and 290 nm to 350 nm than the latter (described later). See examples). Utilizing this, it is possible to confirm that the polycarboxylic acid-based copolymer has a structure (trithiocarbonate structure) represented by the above-mentioned general formula (3). The absorption of the RAFT agent having a specific structure can be confirmed by measuring the UV spectrum of the RAFT agent to be used in advance.

<< Production method of polycarboxylic acid-based copolymer >>
The method for producing a polycarboxylic acid-based copolymer having the above-mentioned structure is not particularly limited, and conventionally known findings are appropriately referred to. However, according to another embodiment of the present invention, the above-mentioned polycarboxylic acid-based copolymer is used. Suitable production methods for producing copolymers are also provided. However, the technical scope of the above-mentioned polycarboxylic acid-based copolymer is not limited to those obtained by the production method described in detail below.

That is, other embodiments of the present invention include the unsaturated polyalkylene glycol-based monomer (a) represented by the general formula (1) and the unsaturated carboxylic acid-based monomer represented by the general formula (2). The present invention relates to a method for producing a polycarboxylic acid-based copolymer, which comprises a polymerization step of polymerizing a monomer component essentially containing a weight (b). The manufacturing method is described in the following general formula (4):

It is characterized in that the polymerization step is carried out in the presence of the trithiocarbonate type compound represented by.

In the method for producing a polycarboxylic acid-based copolymer according to this embodiment, the trithiocarbonate-type compound represented by the general formula (4) functions as a chain transfer agent. Specifically, it functions as a chain transfer agent (ie, RAFT agent) for advancing reversible addition-fragmentation chain transfer (RAFT) polymerization, which is a type of living radical polymerization. As described above, in RAFT polymerization, reactions related to RAFT equilibrium are added to the general free radical polymerization of substituted monomers. And the advantages of RAFT polymerization are that it can control the polymerization reaction of most of the monomers that can be polymerized by radical polymerization, and that unprotected functional groups in the monomers and solvents (eg, -OH, -NR ₂ , -COOH, Highly tolerant to -CONR ₂ , -SO _3H ), polymerizable in water or protonic solvents, wide range of reaction conditions applicable, easy to use and inexpensive compared to competing technologies Is mentioned.

Here, in the general formula (4), Z ¹ and Z ² represent organic residues, and Z ¹ and Z ² are not the same as each other. That is, in the method for producing a polycarboxylic acid-based copolymer according to this embodiment, a RAFT agent having an asymmetric chemical structure is used as a chain transfer agent, and a specific unsaturated polyalkylene glycol-based simpler is used in the presence of the RAFT agent. The polymerization step of polymerizing the monomer component essentially containing the weight (a) and the specific unsaturated carboxylic acid-based monomer (b) is performed. As described above, by performing the polymerization step using a RAFT agent in which Z ₁ and Z ₂ are different, the polymerization can proceed only on one side of the trithiocarbonate structure which is the RAFT active site, and is produced. It is easy to control the structure of the polycarboxylic acid-based copolymer to a desired one, and as a result, the structure of the substituent on the side remaining on the copolymer side after cleavage of the RAFT agent among Z ₁ and Z ₂ is appropriately selected. By doing so, it becomes possible to effectively introduce the structure (trithiocarbonate structure) represented by the above-mentioned general formula (3) into the polycarboxylic acid-based copolymer. It should be noted that, as in the production method according to the present embodiment, by obtaining a polycarboxylic acid-based copolymer by RAFT polymerization even in living polymerization, it is possible to produce the copolymer without the need for a catalyst containing heavy metals and tellurium. Is. Therefore, there is no risk of heavy metals being mixed into the system. Further, by obtaining a polycarboxylic acid-based copolymer by RAFT polymerization, the weight average molecular weight (Mw) and the number average molecular weight (Mw) in terms of polyethylene glycol obtained by gel permeation chromatography of the polycarboxylic acid-based copolymer (Mw). It is possible to lower the dispersity (Mw / Mn) calculated as a ratio to Mn). Then, it is possible to provide a polycarboxylic acid-based copolymer capable of reducing the amount used to achieve a desired fluidity when it is used as a cement composition.

As described above, in the general formula (4), Z ¹ and Z ² represent organic residues. The specific composition of the organic residue is not particularly limited, and any organic residue can be used as long as Z ¹ and Z ² are different.

Examples of the substituents Z ₁ and Z ₂ include a hydrogen atom or a hydrocarbon group composed of an alkyl group, an aryl group, or the like. The carbon chain of these substituents may be a straight chain or a branched chain, and may have a cyclic structure or an unsaturated bond in the middle or at the end. Further, these substituents may be further substituted by at least one of the substituents listed in the description of the general formula (3), and B, N, O, Si, P, S and the like may be added to the carbon chain. Atoms may intervene.

From the viewpoint of hydrophilicity, at least one of the substituents Z ¹ and Z ² is a hydroxy group, an amino group, a carbonyl group, a carboxy group, an amide group, a cyano group, a carbamoyl group, or an oxo acid group (sulfon group, phosphon group). , A phosphin group, etc.) and those having a polar functional group such as an oxo acid ester, and more preferably one having 15 or less carbon atoms per polar functional group. The RAFT agent having such a substituent has a relatively high molecular polarity and is easily uniformly dispersed in a polar solvent, particularly in water, so that a polymer having a lower dispersity can be obtained.

Further, in at least one of the substituents of Z ¹ and Z ² , the carbon atom at the connection end with the sulfur atom constituting the trithiocarbonate structure which is the RAFT active site (hereinafter, also referred to as “ _CA ”) is used. , Secondary or tertiary carbon atom, and in the other substituent of Z ¹ and Z ² , the connection end with the sulfur atom constituting the trithiocarbonate structure which is the RAFT active site. It is more preferable that the carbon atom (hereinafter, also referred to as “ _CB ”) is a primary carbon atom. In such a more preferred embodiment, the RAFT agent is usually cleaved between _CA and the RAFT active site (trithiocarbonate structure) and the chain transfer reaction proceeds. Therefore, the cleaved fragment containing _CA is not introduced into the copolymer. On the other hand, a structure containing a cleavage fragment containing CB and a _RAFT active site (trithiocarbonate structure) will be introduced into the copolymer. From this point of view, of Z ¹ and Z ² , the substituent on the side introduced into the copolymer (usually, the substituent on the _side containing CB) is preferably the above-mentioned general formula (3). The group corresponding to -CH ₂ -Z ⁴ in-CH _2- (substituted or unsubstituted linear, branched or cyclic alkyl group having 1 to 20 carbon atoms) or -CH _2- (substituted ). Or an unsubstituted phenyl group) ). That is, in a preferred embodiment, the trithiocarbonate compound used as a RAFT agent in the method for producing a polycarboxylic acid-based copolymer according to this embodiment has a structure represented by the following general formula (5). .. In the following general formula (5), the carbon atom bonded to the substituents R ⁴¹ to _R ⁴³ corresponds to the above-mentioned CA, and the carbon atom bonded to the substituent Z 4 corresponds to the above _- mentioned CB.

Here, in the general formula (5), Z ⁴ is a substituted or unsubstituted linear, branched or cyclic alkyl group having 1 to 20 carbon atoms. Since the specific example of Z ⁴ in the general formula (5) is the same as that described above for Z ⁴ in the general formula (3), detailed description thereof will be omitted here.

Further, in the general formula (5), R ⁴¹ represents an atom or an atomic group, and R ⁴² and R ⁴³ represent an atom or an atomic group excluding a hydrogen atom independently of each other. Examples of the atom that can form R ⁴¹ to R ⁴³ include a hydrogen atom and a halogen atom. The atomic groups that can constitute R ⁴¹ to R ⁴³ include a substituted or unsubstituted linear, branched or cyclic alkyl group having 1 to 20 carbon atoms and a corresponding alkoxy group, substituted or non-substituted. Substituent linear, branched or cyclic alkenyl groups with 2 to 20 carbon atoms, substituted or unsubstituted linear or unsubstituted alkynyl groups with 2 to 20 carbon atoms, substituted or unsubstituted carbon atoms 6 to 20 aryl groups, substituted or unsubstituted heteroaryl groups with 2 to 20 carbon atoms, substituted or unsubstituted arylalkyl groups with 7 to 20 carbon atoms, substituted or unsubstituted carbon atoms 3 to 20 heteroarylalkyl groups, cyano groups, carboxyl groups, aldehyde groups, carbonyl groups, hydroxyl groups, alkoxy groups, amino groups, imino groups, amide groups, nitro groups, as well as functional groups containing phosphorus such as phosphate groups , A functional group containing sulfur such as a thiol group and a sulfone group. Some of these atomic groups may be replaced with another atomic group, or another atomic group may be inserted, and the structure of the other atomic group includes a cyano group, a carboxyl group, and an aldehyde. Group, carbonyl group, hydroxyl group, alkoxy group, amino group, imino group, amide group, nitro group, phosphorus-containing functional group such as phosphoric acid group, sulfur-containing functional group such as thiol group and sulfone group, etc. Can be mentioned.

As described above, in one preferred embodiment, Z ⁴ in the general formula (3) is a —CH ₂ COMM group (M is a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, Or an organic amine group) or a substituted or unsubstituted phenyl group. Further, in a more preferable embodiment, Z ⁴ in the general formula (3) is a −CH ₂ COM group. Regarding these preferable forms, Z ⁴ in the general formula (5) is also preferable, and in this case, R ⁴¹ in the general formula (5) is preferably a hydrogen atom, and R ⁴² is a substituted or unsubstituted direct. It is preferably a chain, branched or cyclic alkyl group having 1 to 20 carbon atoms, and R ⁴³ is a −COMM group (M is a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group or an organic ammonium group). , Or an organic amine group). By carrying out the polymerization step using a trithiocarbonate compound (RAFT agent) having such a structure, the polycarboxylic acid-based copolymer has a structure represented by the above-mentioned general formula (3) (trithiocarbo). Nate structure) can be introduced more effectively. As a result, it is possible to provide a polycarboxylic acid-based copolymer capable of reducing the amount used to achieve the desired fluidity when the cement composition is obtained.

Specific examples of the above-mentioned trithiocarbonate compound (RAFT agent) include 2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid and 2- (dodecylthiocarbonylthioilthio) -2. -Methylpropanoic acid, 2-[(dodecylsulfanylthiocarbonyl) sulfanic acid] propanoic acid, 4-cyano-4- (ethylsulfanylthiocarbonylsulfanyl) pentanoic acid, 4-cyano-4- (dodecylsulfanylthiocarbonylsulfanyl) pentanoic acid , 4-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} -4-cyano-pentanoic acid, 4-cyano-4-[(dodecylsulfanylthiocarbonyl) sulfanyl] methylpentanoate, S- (2-cyanopropi) -2-yl) -S-dodecyltrithiocarbonate, S-cyanomethyl-S-dodecyltrithiocarbonate, 2-methyl-2-[(dodecylsulfanylthiocarbonyl) sulfanyl] propanoic acid and the like can be mentioned.

As the conditions for RAFT polymerization that can be adopted to obtain the polycarboxylic acid-based copolymer, any appropriate conditions can be adopted as long as the effects of the present invention are not impaired.

As the conditions for RAFT polymerization, for example, the following conditions are preferable.

(solvent)
The polymerization step (copolymerization step) for obtaining the polycarboxylic acid-based copolymer can be carried out by a usual method such as solution polymerization or bulk polymerization. Solution polymerization can be carried out either in batches or continuously. Any suitable solvent may be used in this case, for example, water; alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol; aromatic or aliphatic carbides such as benzene, toluene, xylene, cyclohexane, n-hexane. Examples thereof include hydrogen; ester compounds such as ethyl acetate; ketone compounds such as acetone and methyl ethyl ketone; cyclic ether compounds such as tetrahydrofuran and dioxane. Above all, from the viewpoint of the solubility of the raw material monomer and the obtained polymer, it is preferable to use at least one selected from the group consisting of water and a lower alcohol having 1 to 4 carbon atoms, and among them, water is a solvent removing step. Is more preferable in that the above can be omitted.

(Polymerization concentration)
The amount of all the monomer components used in the RAFT polymerization is preferably 15% by mass or more, more preferably 20% by mass to 90% by mass, still more preferably, with respect to all the raw materials including other raw materials. Is 25% by mass to 80% by mass, particularly preferably 30% by mass to 60% by mass, and most preferably 35% by mass to 40% by mass. If the amount of all monomer components used in the RAFT polymerization is within the above range, the polymerization rate can be improved, the productivity can be easily improved, and side reactions such as a two-molecule termination reaction are unlikely to occur.

(Amount of RAFT agent added)
In RAFT polymerization, the ratio of the number of moles of RAFT agent added to the number of moles of all monomers is preferably 1/1000 to 1/5, more preferably 1/500 to 1/10. It is more preferably 1/250 to 1/15, particularly preferably 1/130 to 1/20, and most preferably 1/120 to 1/40. When the ratio of the number of moles of the RAFT agent added to the number of moles of the total monomer is within the above range, the amount of the polycarboxylic acid used to achieve the desired fluidity in the case of a cement composition can be further reduced. A system copolymer can be provided.

(Type of polymerization initiator)
As the polymerization initiator for RAFT polymerization, any suitable polymerization initiator can be adopted. Examples of such a polymerization initiator include azo-based initiators and peroxides. Specific examples of the azo-based initiator include 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride (trade name "VA-044" manufactured by Wako Junyaku Kogyo Co., Ltd.). , 2'-Azobisisobuty [2- (imidazolin-2-yl) propane] disulfate dihydrate (trade name "VA-046B" manufactured by Wako Pure Chemical Industries Co., Ltd.), 2, 2'-azobis [2- (2-imidazolin-2-yl) propane] (trade name "VA-061" manufactured by Wako Pure Chemical Industries Co., Ltd., etc.), 2,2'-azobis (2-methylpropionamidine) Dihydrochloride (trade name "V-50" manufactured by Wako Junyaku Kogyo Co., Ltd., etc.), 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] n hydrate (Japanese Product name "VA-057" manufactured by Kojunyaku Kogyo Co., Ltd.), 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide] (trade name manufactured by Wako Junyaku Kogyo Co., Ltd.) "VA-086" etc.), 4,4'-azobis (4-cyanovaleric acid) (trade name "V-501" manufactured by Wako Pure Chemical Industries Co., Ltd.), 2,2'-azobis (4-methoxy) -2,4-dimethylvaleronitrile) (trade name "V-70" manufactured by Wako Pure Chemical Industries, Ltd.), 2,2'-azobis (2,4-dimethylvaleronitrile) (Wako Pure Chemical Industries, Ltd.) (Product name "V-65", etc.), 2,2'-azobis (isobutyronitrile) (AIBN), 2,2'-azobis (2-methylbutyronitrile) (manufactured by Wako Pure Chemical Industries, Ltd.) (Product name "V-59", etc.), 1,1'-azobis (cyclohexane-1-carbobisisobuty) (trade name "V-40", etc. manufactured by Wako Pure Chemical Industries Co., Ltd.), 2,2'-azobis [N- (2-propenyl) -2-methylpropionamide] (trade name "VF-096" manufactured by Wako Pure Chemical Industries, Ltd., etc.), 2,2'-azobis (N-butyl-2-methylpropionamide) ) (Product name "VAm-110" manufactured by Wako Junyaku Kogyo Co., Ltd.), 2,2'-azobis (isobutyric acid) dimethyl (trade name "V-601" manufactured by Wako Junyaku Kogyo Co., Ltd.), etc. Can be mentioned. Examples of peroxides include hydrogen peroxide, benzoyl peroxide, tertiary butyl hydroperoxide (trade name "Perbutyl H-69" manufactured by Nichiyu Co., Ltd., etc.), 1,1,3,3-tetramethylbutylhydroperoxide. (Product name "Perocta H" manufactured by Nichiyu Co., Ltd., etc.) and the like.

(Ratio of RAFT agent and polymerization initiator)
In RAFT polymerization, the polymerization reaction is started with a small amount of polymerization initiator. If the amount of the polymerization initiator is too small, the polymerization reaction will not proceed well because the initial radical concentration is low, and conversely, if the amount is too large, the initial radical concentration will increase and free radical polymerization will proceed at the same time, resulting in a copolymer with a narrow degree of dispersion. Cannot be obtained. For a polymerization initiator such as hydrogen peroxide, in which only one radical is generated from the cleavage of one molecule of the polymerization initiator, the ratio of the number of moles of the polymerization initiator to the number of moles of the RAFT agent is preferably 20 mol% to 80 mol. %, More preferably 30 mol% to 70 mol%, still more preferably 35 mol% to 65 mol%, particularly preferably 40 mol% to 60 mol%, and most preferably 45 mol% to. It is 55 mol%. When an azo-based initiator such as the trade name "V-50" manufactured by Wako Pure Chemical Industries, Ltd. is used, two radicals are generated from the cleavage of one molecule of the polymerization initiator, so that the number of moles of the RAFT agent is increased. The ratio of the number of moles of the polymerization initiator is preferably 10 mol% to 40 mol%, more preferably 15 mol% to 35 mol%, still more preferably 17 mol% to 32 mol%, and particularly. It is preferably 20 mol% to 30 mol%, and most preferably 22 mol% to 28 mol%.

(Polymerization temperature)
In RAFT polymerization, the polymerization temperature is appropriately determined by the polymerization method, solvent, polymerization initiator, chain transfer agent, etc. used, but the lower limit is preferably 0 ° C. or higher, more preferably 30 ° C. or higher, and further. The temperature is preferably 50 ° C. or higher, and the upper limit is preferably 150 ° C. or lower, more preferably 120 ° C. or lower, and further preferably 100 ° C. or lower.

(Monomer addition method)
As a method of charging each monomer into the reaction vessel, a method of initially charging the entire amount into the reaction vessel, a method of dividing or continuously charging the entire amount into the reaction vessel, and a method of initially charging a part into the reaction vessel and the rest. Can be divided or continuously charged into the reaction vessel. As a suitable charging method, specifically, a method of continuously charging the monomer (a) and all of the monomer (b) into the reaction vessel, and a method of continuously charging a part of the monomer (a) into the reaction vessel. A method in which the remainder of the monomer (a) and the entire monomer (b) are continuously charged into the reaction vessel at the initial stage, a part of the monomer (a) and one of the monomers (b). Examples thereof include a method in which the portions are initially charged into the reaction vessel, and the remainder of the monomer (a) and the remainder of the monomer (b) are alternately charged into the reaction vessel in several divided portions. Further, by continuously or stepwise changing the charging rate of each monomer into the reaction vessel during the reaction, the charging mass ratio of each monomer per unit time is continuously or stepwise changed to carry out polypoly. The polymer may be polymerized so that the ratio of the structural unit (I) and the structural unit (II) in the carboxylic acid-based copolymer changes continuously or stepwise in the same polymer chain. The polymerization initiator and the chain transfer agent may be charged into the reaction vessel from the beginning, may be dropped into the reaction vessel, or may be combined depending on the purpose.

(Dissolved oxygen concentration)
In RAFT polymerization, in order to obtain a polycarboxylic acid-based copolymer having a predetermined molecular weight with good reproducibility, it is necessary to allow the copolymerization reaction to proceed stably. Therefore, when solution polymerization is performed, the solvent used is used. The dissolved oxygen concentration at 25 ° C. is preferably 5 ppm or less. The dissolved oxygen concentration is more preferably 0.01 ppm to 4 ppm, further preferably 0.01 ppm to 2 ppm, and particularly preferably 0.01 ppm to 1 ppm. When nitrogen substitution or the like is performed after adding the monomer to the solvent, it is preferable that the dissolved oxygen concentration of the system including the monomer is within the above range. The dissolved oxygen concentration of the solvent may be adjusted in a polymerization reaction tank, or a solvent having a dissolved oxygen amount adjusted in advance may be used. Examples of the method for expelling oxygen in the solvent include the following methods (1) to (5).
(1) After pressure-filling the closed container containing the solvent with an inert gas such as nitrogen, the pressure inside the closed container is lowered to lower the partial pressure of oxygen in the solvent. The pressure in the closed container may be reduced under a nitrogen stream.
(2) The liquid phase portion is vigorously stirred for a long time while the gas phase portion in the container containing the solvent is replaced with an inert gas such as nitrogen.
(3) The solvent contained in the container is bubbled with an inert gas such as nitrogen for a long time.
(4) After boiling the solvent once, it is cooled under the atmosphere of an inert gas such as nitrogen.
(5) A static mixer is installed in the middle of the pipe, and an inert gas such as nitrogen is mixed in the pipe that transfers the solvent to the polymerization reaction tank.

(PH adjustment)
The obtained polycarboxylic acid-based copolymer can be used as it is as an additive for inorganic particles, but it is preferable to adjust the pH to 5 or more from the viewpoint of handleability. However, in order to improve the polymerization rate, it is preferable to carry out the copolymerization reaction at a pH of less than 5 and adjust the pH to 5 or more after the copolymerization. The pH is adjusted by adjusting the pH to one of alkaline substances such as monovalent metals such as sodium hydroxide, potassium hydroxide, calcium hydroxide and inorganic salts such as hydroxides and carbonates of divalent metals; ammonia; organic amines; It can be performed using two or more types. Further, after the reaction is completed, the concentration can be adjusted if necessary.

The concentration of the produced polycarboxylic acid-based copolymer can be adjusted as necessary with respect to the solution obtained by the production.

The produced polycarboxylic acid-based copolymer may be used as it is in the form of a solution, or may be powdered and used.

<< Additives for inorganic particles >>
The polycarboxylic acid-based copolymer according to one embodiment of the present invention described above and the polycarboxylic acid-based copolymer produced by the production method according to another embodiment of the present invention can be used for various purposes. One example is an additive for inorganic particles.

The content ratio of the polycarboxylic acid-based copolymer in the solid content of the additive for inorganic particles is preferably 45% by mass to 99.98% by mass, more preferably 70% by mass to 99.95% by mass. It is more preferably 85% by mass to 99.92% by mass, and particularly preferably 90% by mass to 99.9% by mass.

When the polycarboxylic acid-based copolymer according to the present invention is used as an additive for inorganic particles, the additive for inorganic particles preferably contains a defoaming agent.

As the defoaming agent, any suitable defoaming agent can be used. According to the embodiment of the present invention, an additive for inorganic particles is formed by combining a specific polycarboxylic acid-based copolymer as described above and a defoaming agent, and this is used as an additive for cement. A cement composition having particularly excellent fluidity can be obtained. That is, a preferable example of the additive for inorganic particles according to the present invention is an additive for cement. Here, examples of the defoaming agent include an oxyalkylene-based defoaming agent and a defoaming agent other than the oxyalkylene-based defoaming agent.

Examples of the oxyalkylene-based defoaming agent include polyoxyalkylenes such as (poly) oxyethylene (poly) oxypropylene adduct; polyoxyalkylene alkyl ethers such as diethylene glycol heptyl ether; polyoxyalkylene acetylene ethers; Poly) Oxyalkylene fatty acid esters; Polyoxyalkylene sorbitan fatty acid esters; Polyoxyalkylene alkyl (aryl) ether sulfate esters; Polyoxyalkylene alkyl phosphate esters; Polyoxypropylene polyoxyethylene laurylamine (propylene oxide 1 to Poly such as 20 mol addition, ethylene oxide 1 to 20 mol addition, etc.), amine derived from fatty acid obtained from hardened beef fat to which alkylene oxide is added (propylene oxide 1 to 20 mol addition, ethylene oxide 1 to 20 mol addition, etc.) Examples thereof include oxyalkylene alkylamines; polyoxyalkylene amides and the like;

Examples of defoamers other than oxyalkylene-based defoamers include mineral oil-based, oil-based, fatty acid-based, fatty acid ester-based, alcohol-based, amide-based, phosphate ester-based, metal soap-based, and silicone-based defoaming agents. Be done.

The content ratio of the defoaming agent in the solid content of the additive for inorganic particles is preferably 0.02% by mass to 70% by mass, more preferably 0.05% by mass to 10% by mass, and further preferably. It is 0.08% by mass to 6% by mass, and particularly preferably 0.1% by mass to 4% by mass.

The total content of the polycarboxylic acid-based copolymer and the defoaming agent in the solid content of the additive for inorganic particles is preferably 50% by mass to 100% by mass, and more preferably 75% by mass to 100% by mass. %, More preferably 90% by mass to 100% by mass, and particularly preferably 95% by mass to 100% by mass.

The content ratio (polycarboxylic acid-based copolymer / defoaming agent) (mass ratio) of the polycarboxylic acid-based copolymer and the defoaming agent in the additive for inorganic particles is preferably 1/2 to 5000/1. Yes, more preferably 10/1 to 2000/1, still more preferably 15/1 to 1000/1, and particularly preferably 30/1 to 750/1.

Additives for inorganic particles may contain any suitable additional ingredients. As additional components, for example, a sulfonic acid-based dispersant having a sulfonic acid group in a molecule that can be used as a cement admixture, a polycarboxylic acid-based dispersant other than the polycarboxylic acid-based copolymer according to the present invention, and a highly water-soluble dispersant. Molecular substances, polymer emulsions, curing retarders, fast-strengthening agents / accelerators, AE agents, crack reducing agents, surfactants, waterproofing materials, rust preventives, cement wetting agents, thickeners, separation reducing agents, flocculants , Dry shrinkage reducing agent, strength enhancer, self-leveling agent, coloring agent, antifungal agent and the like.

Examples of the sulfonic acid-based dispersant include polyalkylaryl sulfonate-based sulfonic acid-based dispersants such as naphthalene sulfonic acid formaldehyde condensate, methylnaphthalene sulfonic acid formaldehyde condensate, and anthracene sulfonic acid formaldehyde condensate; melamine sulfonic acid. Melamine formalin resin sulfonate-based sulfonic acid-based dispersants such as formaldehyde condensates; aromatic aminosulfonate-based sulfonic acid-based dispersants such as aminoaryl sulfonic acid-phenol-formaldehyde condensates; lignin sulfonates, Examples thereof include a lignin sulfonate-based sulfonic acid-based dispersant such as a modified lignin sulfonate; a polystyrene sulfonate-based sulfonic acid-based dispersant; and the like.

Examples of the water-soluble polymer substance include nonionic cellulose ethers such as methyl cellulose, ethyl cellulose, and carboxymethyl cellulose; polysaccharides produced by microbial fermentation such as yeast glucan, xanthan gum, and β-1.3 glucan; polyethylene glycol. Polyoxyalkylene glycols and the like; polyacrylamide and the like can be mentioned.

Examples of the polymer emulsion include copolymers of various vinyl monomers such as alkyl (meth) acrylate.

Examples of the curing retarder include oxycarboxylic acids such as gluconic acid, glucoheptonic acid, arabonic acid, malic acid and citric acid or salts thereof; sugars and sugar alcohols; polyhydric alcohols such as glycerin; aminotri (methylenephosphonic acid) and the like. Phosphoric acid and its derivatives thereof.

Examples of the fast-strengthening agent / accelerator include soluble calcium salts such as calcium chloride, calcium nitrite, calcium nitrate, calcium bromide and calcium iodide; chlorides such as iron chloride and magnesium chloride; sulfates; potassium hydroxide. ; Sodium hydroxide; carbonate; thiosulfate; formate such as formic acid and calcium formate;

Examples of the AE agent include resin soap, saturated or unsaturated fatty acid, sodium hydroxystearate, lauryl sulfate, ABS (alkylbenzene sulfonic acid), alkanesulfonate, polyoxyethylene alkyl (phenyl) ether, and polyoxyethylene alkyl (phenyl). Examples thereof include ether sulfate ester or a salt thereof, polyoxyethylene alkyl (phenyl) ether phosphate ester or a salt thereof, protein material, alkenyl sulfosuccinic acid, α-olefin sulfonate and the like.

Examples of the surfactant include various anionic surfactants; various cationic surfactants such as alkyltrimethylammonium chloride; various nonionic surfactants; various amphoteric surfactants and the like.

Examples of the waterproofing agent include fatty acids (salts), fatty acid esters, fats and oils, silicones, paraffins, asphalts, waxes and the like.

Examples of the rust preventive include nitrite, phosphate, zinc oxide and the like.

Examples of the crack reducing agent include polyoxyalkyl ethers and the like.

The content ratio of the additional component in the solid content of the additive for inorganic particles is preferably 0% by mass to 50% by mass, more preferably 0% by mass to 10% by mass, and further preferably 0% by mass to 1%. It is by mass, and particularly preferably 0% by mass to 0.1% by mass.

The types, combinations, blending amounts, etc. of additional components in the additive for inorganic particles can be appropriately set according to the purpose.

《Cement composition》
According to another embodiment of the present invention, the cement additive (including a polycarboxylic acid-based copolymer and, if necessary, a defoaming agent), which is an embodiment of the additive for inorganic particles according to the above-mentioned embodiment. , Cement and cement compositions are provided. Practically, the cement composition further comprises water and aggregate. The cement composition may further contain the above-mentioned additional components, if necessary. Further, the cement composition may contain each of the above-mentioned components as an additive for cement.

The content of the additive for cement in the cement composition is preferably 0.001% by mass to 10% by mass, more preferably 0.005% by mass to 5% by mass, based on the solid content of the cement. It is more preferably 0.01% by mass to 3% by mass, particularly preferably 0.05% by mass to 2% by mass, and most preferably 0.1% by mass to 1% by mass. As described above, the cement additive according to the embodiment of the present invention can exhibit the effect that the amount used for achieving the desired fluidity can be reduced when the cement composition is prepared.

The content of the polycarboxylic acid-based polymer in the cement composition is, in terms of solid content, preferably 0.02% by mass to 5% by mass, and more preferably 0.05% by mass to 1% by mass with respect to the cement. It is by mass, more preferably 0.1% by mass to 0.5% by mass, and particularly preferably 0.13% by mass to 0.2% by mass.

The content of the defoaming agent in the cement composition is preferably 0.00001% by mass to 1% by mass, more preferably 0.00002% by mass to 0.1% by mass, based on the solid content of the cement. It is more preferably 0.00005% by mass to 0.01% by mass, and particularly preferably 0.0001% by mass to 0.008% by mass.

As the aggregate, any suitable aggregate such as fine aggregate (sand or the like) or coarse aggregate (crushed stone or the like) can be adopted. Examples of such aggregates include gravel, crushed stone, granulated slag, and recycled aggregate. Further, examples of such aggregates include refractory aggregates such as silica stone, clay, zircon, high alumina, silicon carbide, graphite, chromium, chromog and magnesia.

As the cement contained in the cement composition, any suitable cement may be adopted. Examples of such cement include Portoland cement (ordinary, early-strength, ultra-fast-strength, moderate heat-resistant, sulfate-resistant and each low-alkali form), various mixed cements (blast furnace cement, silica cement, fly ash cement), and the like. White Portoland Cement, Alumina Cement, Ultra Fast Hard Cement (1 Clinker Fast Hard Cement, 2 Clinker Fast Hard Cement, Magnesium Phosphate Cement), Grout Cement, Oil Well Cement, Low Heat Cement (Low Heat Heat Type High Furnace Cement, Fly Ash Mixed Low) Heat-generating blast furnace cement, belite-rich cement), ultra-high-strength cement, cement-based solidifying material, eco-cement (cement manufactured from one or more of municipal waste incineration ash and sewage sludge incineration ash). Further, fine powder such as blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica powder, limestone powder, gypsum, and expansion material (for example, ettringite-based, coal-based) are added to the cement composition. You may. The cement contained in the cement composition may be only one kind or two or more kinds.

In the cement composition, any appropriate value can be set as the unit water amount per 1 m ³ of the cement composition, the amount of cement used, and the water / cement ratio. As such values, preferably, the unit water amount is 100 kg / m ³ to 185 kg / m ³ , the amount of cement used is 250 kg / m ³ to 800 kg / m ³ , and the water / cement ratio (mass ratio) =. It is 0.1 to 0.7, more preferably the unit water amount is 120 kg / m ³ to 175 kg / m ³ , the amount of cement used is 270 kg / m ³ to 800 kg / m ³ , and the water / cement ratio ( Mass ratio) = 0.12 to 0.65. As described above, the cement composition can be widely used from poor to rich concrete, and is effective for both high-strength concrete having a large unit cement amount and poor concrete with a unit cement amount of 300 kg / m ³ or less. ..

The cement composition may be effective for ready-mixed concrete, concrete for secondary concrete products, concrete for centrifugal molding, concrete for vibration compaction, steam curing concrete, sprayed concrete and the like. The cement composition of the present invention includes medium-fluidity concrete (concrete with a slump value of 22 to 25 cm), high-fluidity concrete (concrete with a slump value of 25 cm or more and a slump flow value of 50 to 70 cm), self-filling concrete, and self. It can also be effective for mortar and concrete that require high fluidity such as leveling materials.

The cement composition may be prepared by blending the constituent components by any suitable method. For example, a method of kneading the constituents in a mixer may be mentioned.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. Unless otherwise specified, the term "part" means "parts by mass", and the term "%" means "% by mass".

<Measurement conditions for weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn)>
The weight average molecular weight and the molecular weight distribution were measured under the following measurement conditions.
Device: Waters Alliance (2695)
Analysis software: Waters, Emper Professional + GPC option column: Tosoh, TSKgel guard column (inner diameter 6.0 mm x 40 mm) + TSKgel G4000SWXL (inner diameter 7.8 mm x 300 mm) + G3000SWXL (inner diameter 7.8 mm x 300 mm) + G2000SWXL (inner diameter 7.8 mm x 300 mm) Inner diameter 7.8 mm x 300 mm)
Detector: Differential Refractometer (RI) Detector (Waters 2414), Photodiode Array (PDA) Detector (Waters 2996)
Eluent: 115.6 g of sodium acetate trihydrate dissolved in a mixed solvent of 10999 g of water and 6001 g of acetonitrile, and the pH was adjusted to 6.0 with acetic acid.
GPC standard sample: Polyethylene glycol manufactured by GL Science (Peak Top Molecular Weight (Mp) 272500, 219300, 107000, 50000, 24000, 11840, 6450, 4250, 1470)
Calibration curve: Prepared by a cubic formula using the Mp value of the above polyethylene glycol.
Flow rate: 1.0 mL / min Column temperature: 40 ° C
Measurement temperature: 40 ° C
Measurement time: 45 minutes Sample solution injection amount: 100 μL (eluent solution with sample concentration of 0.5% by mass)
Standard sample injection volume: 100 μL (concentration 0.1% by mass eluent solution)
Analytical method: In the obtained RI chromatogram (GPC chart), as shown in the example of FIG. 1, a straight line (straight line in the example of FIG. 1) shows a flat and stable portion at the baseline immediately before and immediately after the polymer elution. The polymer was detected and analyzed by connecting with L). However, when the monomer peak is measured so as to overlap the polymer peak (M is the monomer peak in the example of FIG. 1), it is vertically divided at the innermost recess of the overlapping portion of the monomer and the polymer (straight lines a and b in the example of FIG. 1). ) The polymer part and the monomer part (the shaded part in the example of FIG. 1) were separated, and the molecular weight and the molecular weight distribution of only the polymer part were measured. When oligomers larger than dimer were detected, they were included in the polymer part.

<Analysis method of composition of structural units>
In Table 1 below, the "composition ratio of structural units (mass ratio (I) / (II))" is a single amount charged into a reaction vessel for producing a copolymer by LC (liquid chromatography). It is a composition ratio (mass ratio) of a structural unit calculated by analyzing the consumption rate of a body in a polymerization reaction and assuming that all the consumed monomers are converted into a copolymer by the polymerization reaction. The analysis conditions and methods for LC (liquid chromatography) are as follows.

(LC analysis conditions)
Model: Waters Alliance (2695)
Analysis software: Waters, Emper2 Professional column: Waters, Atlantis dC18 guard column + Atlantis dC18, 4.6 x 250 mm, 2 pieces
Detector: Differential Refractometer (RI) detector (Waters 2414), multi-wavelength visible ultraviolet (PDA) detector (Waters 2996)
Eluent: 3.75 g of sodium acetate trihydrate and 52.2 g of acetic acid dissolved in a mixed solvent of 9000 g of water and 6000 g of acetonitrile.
Flow rate: 1 mL / min Column temperature: 40 ° C
(LC analysis method)
A calibration curve of each monomer was prepared, and the consumption amount was determined from the residual amount of each monomer in the polymer solution after polymerization.

<Qualitative analysis of terminal structure of polycarboxylic acid copolymer>
A qualitative analysis of the polycarboxylic acid-based copolymer having the structure represented by the above-mentioned general formula (3) (trithiocarbonate structure) was performed by comparing UV spectra. The analysis method is as follows.

(UV spectrum analysis method)
For the analysis, the copolymer of Synthesis Example 1 described later obtained by polymerizing using 2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid or mercaptopropionic acid as a chain transfer agent, respectively ( The copolymer (C1) of 1) and Comparative Synthesis Example 1 was used. The UV spectra of these copolymers are obtained by analyzing the copolymer by the method described in the above-mentioned <Measuring conditions of weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn)> on the RI chart obtained. The observed dissolution time of the polymer portion (L shown in FIG. 1) was confirmed, and the absorption spectrum of the PDA chart at the dissolution time was cut out. Further, the UV spectrum of 2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid was obtained from the PDA chart obtained by analyzing the compound by the method described in the above-mentioned <LC analysis conditions>. It was obtained by cutting out the absorption spectrum at the elution time of the compound (not shown). The UV spectrum of 2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propionic acid showed a maximum peak at 305 nm.

<Mortar test>
The composition of the materials and mortar used in the test was 900 g of Pacific ordinary Portland cement, 1350 g of ISO standard sand for strength test, and 270 g of ion-exchanged water containing each copolymer and defoaming agent (MA404). The amount of the defoaming agent added was 1% by mass in terms of solid content with respect to the amount of solid content added to each copolymer. A mortar is prepared by mechanically kneading with a Hobart mixer for 4 minutes at a room temperature of 20 ° C. and a relative humidity of 55% using the following kneading method to obtain a metal flow cone having an upper inner diameter of 70 mm, a lower inner diameter of 100 mm and a height of 60 mm. Filled with mortar. Next, after 5.5 minutes after water injection, the flow cone was lifted vertically, and then the diameter of the mortar spread on the table was measured in two orthogonal directions, and this average was taken as the mortar flow value.

(Kneading method)
A kneader (Hobert Japan Co., Ltd., Mixer N50) is used to knead the mortar of each batch. The operation of the kneader is performed as follows. Add cement to the kneading pot and add water containing each polymer and defoaming agent. The kneader is then immediately started at low speed and after 30 seconds, sand is added in the next 30 seconds. Speed up the kneader and then knead for 30 seconds. Pause the kneader for 90 seconds. During the first 15 seconds of rest, scrape off the mortar adhering to the kneading bowl. Continue kneading at high speed for 60 seconds.

[Synthesis Example 1]
240 parts of ion-exchanged water, 136 parts of unsaturated alcohol with 50 mol of ethylene oxide added to 3-methyl-3-butene-1-ol in a glass reaction vessel equipped with a thermometer, agitator, dropping funnel, and reflux condenser. , 22.9 parts of acrylic acid, 2,2'-azobis (2-methylpropionamidine) dihydrochloride (trade name "V-50" manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator, 0.183 parts, 0.686 parts of 2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid was charged as a chain transfer agent, stirred at 300 rpm, and the inside of the reaction vessel was replaced with nitrogen at 500 mL / min for 30 minutes, and then 70. The temperature was raised to ° C. Then, the polymerization reaction was completed by maintaining the temperature at 70 ° C. for 3 hours continuously to obtain a cement additive (1) composed of an aqueous solution of the copolymer (1) having a weight average molecular weight (Mw) of 26200. The polymer physical characteristics of the obtained copolymer (1) are shown in Table 1 below. The results of the mortar test are shown in Table 2 below. The 2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propionic acid (described as "Ci" in Table 1 below) used as a chain transfer agent in this synthetic example has the following chemical structure. Have.

[Synthesis Example 2]
240 parts of ion-exchanged water and 140 parts of unsaturated alcohol with 50 mol of ethylene oxide added to 3-methyl-3-butene-1-ol in a glass reaction vessel equipped with a thermometer, agitator, dropping funnel, and reflux condenser. , 19.0 parts of acrylic acid, 2,2'-azobis (2-methylpropionamidine) dihydrochloride (trade name "V-50" manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator, 0.110 parts, 0.413 parts of 2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid was charged as a chain transfer agent, stirred at 300 rpm, and the inside of the reaction vessel was replaced with nitrogen at 500 mL / min for 30 minutes, and then 70. The temperature was raised to ° C. Then, the polymerization reaction was completed by maintaining the temperature at 70 ° C. for 3 hours continuously to obtain a cement additive (2) composed of an aqueous solution of the copolymer (2) having a weight average molecular weight (Mw) of 34500. The polymer physical characteristics of the obtained copolymer (2) are shown in Table 1 below. The results of the mortar test are shown in Table 2 below.

[Comparative synthesis example 1]
An unsaturated alcohol in which 87.8 parts of ion-exchanged water and 50 mol of ethylene oxide are added to 3-methyl-3-buten-1-ol in a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, and a reflux cooler. 186 parts and 0.335 parts of acrylic acid were charged, and the temperature was raised to 60 ° C. while stirring in the reaction vessel at 500 mL / min with nitrogen at 500 mL / min, and then the polymerization initiator, aqueous solution 2.00. A solution obtained by adding 17.49 parts of a% aqueous solution and dissolving 30.9 parts of acrylic acid in 18.3 parts of ion-exchanged water was added to 1.04 parts of 3-mercaptopropionic acid, which is a chain transfer agent, and a reducing agent for 3 hours. An aqueous solution prepared by dissolving 1.91 parts of L-ascorbic acid in 58.1 parts of ion-exchanged water was added dropwise over 3.5 hours. After the completion of the dropping, the temperature was maintained at 60 ° C. for 1 hour to complete the polymerization reaction, and a cement additive (C1) composed of an aqueous solution of the copolymer (C1) having a weight average molecular weight (Mw) of 30300 was obtained. .. The polymer physical characteristics of the obtained copolymer (C1) are shown in Table 1 below. The results of the mortar test are shown in Table 2 below. The 3-mercaptopropionic acid (denoted as "Cii" in Table 1 below) used as a chain transfer agent in this comparative synthetic example has the following chemical structure.

[Comparative synthesis example 2]
An unsaturated alcohol in which 42.6 parts of ion-exchanged water and 50 mol of ethylene oxide are added to 3-methyl-3-buten-1-ol in a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, and a reflux cooler. 191 parts and 0.345 parts of acrylic acid were charged, and the temperature was raised to 60 ° C. while stirring the inside of the reaction vessel at 500 mL / min with nitrogen at 300 rpm, and then the polymerization initiator, aqueous solution 2.00. % 15.0 parts of aqueous solution was added, and 25.5 parts of acrylic acid was dissolved in 37.9 parts of ion-exchanged water for 3 hours, 0.610 parts of 3-mercaptopropionic acid as a chain transfer agent, and a reducing agent. An aqueous solution prepared by dissolving 0.389 parts of L-ascorbic acid in 38.9 parts of ion-exchanged water was added dropwise over 3.5 hours. After the completion of the dropping, the temperature was maintained at 60 ° C. for 1 hour to complete the polymerization reaction, and a cement additive (C2) composed of an aqueous solution of the copolymer (C2) having a weight average molecular weight (Mw) of 40300 was obtained. .. The polymer physical characteristics of the obtained copolymer (C2) are shown in Table 1 below. The results of the mortar test are shown in Table 2 below.

FIG. 2 shows the measurement results of the UV spectrum. In order to compare the two copolymers, the amount of UV absorption of the copolymer increases in proportion to the concentration, so the UV / RI ratio standardized by dividing by the signal intensity of RI, which is also proportional to the concentration, is used. The vertical axis is used. It can be seen that in the copolymer having the structure represented by the chemical formula (7), the intensity of UV absorption in the vicinity of 290 nm to 350 nm is high. As described above, the UV spectrum of 2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid showed a maximum peak at 305 nm. Therefore, according to the UV spectrum shown in FIG. 2, the coweight. It was confirmed that the coalescence (1) had a structure represented by the chemical formula (7) derived from 2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid. The terminal structure of the polymer main chain inferred from this result is shown in Table 1 below.

In Table 2, as is clear from the comparison of the same monomer composition ratios, that is, Example 1 and Comparative Example 1, and Example 2 and Comparative Example 2, the additive for inorganic particles of the present invention is an inorganic particle of Comparative Example. The flow value is remarkably higher than that of the additive, and the industrial significance of being able to reduce the amount used to achieve the same flow value is very great.

The additive for inorganic particles containing the polycarboxylic acid-based copolymer according to the present invention, typically the additive for cement, is suitably used for cement compositions such as cement paste, mortar, and concrete.

Claims (10)

The following general formula (1):

In the general formula (1), R ¹ and R ² represent the same or different hydrogen atom or methyl group, R ³ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and AO represents a hydrocarbon group. Represents an oxyalkylene group having 2 to 18 carbon atoms, n represents the average number of moles of the oxyalkylene group represented by AO, n is an integer of 1 to 500, and x is an integer of 0 to 2. be,
The structural unit (I) derived from the unsaturated polyalkylene glycol-based monomer (a) represented by and the following general formula (2):

In the general formula ( ² ), ^R4 to R6 represent the same or different hydrogen atom, methyl group, or-(CH ₂ ) _z COOM group, and-(CH ₂ ) _z COOM group is -COOX group or It may form an anhydride with another − (CH ₂ ) _z COMM group, z is an integer of 0 to 2, and M is a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, or an organic ammonium. A group or an organic amine group, where X represents a hydrogen atom, a methyl group, an ethyl group, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group.
A polycarboxylic acid-based copolymer having a structural unit (II) derived from the unsaturated carboxylic acid-based monomer (b) represented by.
The following general formula (3):

In the general formula (3), Z ⁴ is a substituted or unsubstituted linear, branched or cyclic alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted phenyl group .
A polycarboxylic acid-based copolymer characterized by having a structure represented by. Z ⁴ in the general formula (3) is a -CH ₂ COM group (M represents a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group) or substituted or unsubstituted. The polycarboxylic acid-based copolymer according to claim 1, which is a phenyl group of the above. Claimed that the polyethylene glycol-equivalent weight average molecular weight (Mw) obtained by gel permeation chromatography (GPC) is in the range of 500 to 100,000 and the dispersity (Mw / Mn) is 1.0 to 1.8. Item 2. The polycarboxylic acid-based copolymer according to Item 1. The polycarboxylic acid-based copolymer according to any one of claims 1 to 3 , wherein R ² in the general formula (1) is a methyl group. An additive for inorganic particles, which comprises the polycarboxylic acid-based copolymer according to any one of claims 1 to 4. A cement composition comprising the polycarboxylic acid-based copolymer according to any one of claims 1 to 4. The following general formula (1):

In the general formula (1), R ¹ and R ² represent the same or different hydrogen atom or methyl group, R ³ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and AO represents a hydrocarbon group. Represents an oxyalkylene group having 2 to 18 carbon atoms, n represents the average number of moles of the oxyalkylene group represented by AO, n is an integer of 1 to 500, and x is an integer of 0 to 2. be,
The unsaturated polyalkylene glycol-based monomer (a) represented by the following, and the following general formula (2):

In the general formula (2), R4 ^{to R6} represent the same or different hydrogen atom, methyl group, or-(CH ₂ ) _z COOM group, and- (CH ₂ ) _z COOM group is -COOX group or It may form an anhydride with another − (CH ₂ ) _z COMM group, z is an integer of 0 to 2, and M is a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, or an organic ammonium. A group or an organic amine group, where X represents a hydrogen atom, a methyl group, an ethyl group, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group.
A method for producing a polycarboxylic acid-based copolymer, which comprises a polymerization step of polymerizing a monomer component essentially containing an unsaturated carboxylic acid-based monomer (b) represented by.
The following general formula (4):

In general formula (4), Z ¹ and Z ² represent organic residues, and Z ¹ and Z ² are not identical to each other.
A method for producing a polycarboxylic acid-based copolymer, which comprises performing the polymerization step in the presence of the trithiocarbonate type compound represented by. The trithiocarbonate type compound has the following general formula (5):

In the general formula (5), Z ⁴ is a substituted or unsubstituted linear, branched or cyclic alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted phenyl group , and R ⁴¹ is an atom. Or, they represent an atomic group, and R ⁴² and R ⁴³ represent an atom or an atomic group that is independent of each other and excludes a hydrogen atom.
The method for producing a polycarboxylic acid-based copolymer according to claim 7, which has a structure represented by. Z ⁴ in the general formula (5) is a -CH ₂ COM group (M represents a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group) or substituted or unsubstituted. The method for producing a polycarboxylic acid-based copolymer according to claim 8 , which is the phenyl group of the above. The ninth aspect of the present invention, wherein R ⁴³ in the general formula (5) is a −COMM group (M represents a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group). Method for producing a polycarboxylic acid-based copolymer.

Images