JP2015074667A - (poly)alkylene glycol-based block copolymer and use thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copolymer that can exhibit at high level, performance such as water-reducing property and usability in cement composition or the like, that has simple molecular structure, and that is suitable for industrial production.SOLUTION: There is provided a (poly)alkylene glycol-based block copolymer essentially having structure in which a polymer chain (A) composed of unsaturated carboxylic acid-based monomer units and a polymer chain (B) composed of (poly)alkylene glycol-based structure units are bonded via a binding site (X), and in which the (poly)alkylene glycol-based block copolymer has structure in which the polymer chain (A) and the polymer chain (B) are bonded via a binding site (X) in the order of the polymer chain (A), polymer chain (B) and polymer chain (A), and the binding site (X) does not form an ester linkage with the terminal oxygen atom of polymer chain (B) and the binding site (X) includes a sulfur atom.

Description

The present invention relates to a (poly) alkylene glycol block copolymer. More specifically, the present invention relates to a polyalkylene glycol block copolymer suitably used for applications such as a dispersant and a cement admixture, a dispersant containing the copolymer, a cement admixture, and a cement composition.

A polymer containing a (poly) alkylene glycol chain (hereinafter, also referred to as a (poly) alkylene glycol polymer) has hydrophilicity, hydrophobicity, and steric repulsion by appropriately adjusting the chain length and the constituent alkylene oxide. Therefore, it is utilized in cement admixture applications added to cement compositions such as cement paste, mortar and concrete. Such a cement admixture is usually used as a water reducing agent or the like, and exerts the action of improving the strength and durability of the cured product by reducing the cement composition by increasing the fluidity of the cement composition. Used for that purpose. As a water reducing agent, a water reducing agent such as a naphthalene type has been conventionally used, but a (poly) alkylene glycol chain can act as a dispersing group for dispersing cement particles due to its steric repulsion. A polycarboxylic acid-based water reducing agent containing a glycol chain has been proposed as exhibiting a high water reducing action, and has recently been used as a high-performance AE water reducing agent.

With respect to a conventional polymer containing a (poly) alkylene glycol chain, development research on a block copolymer having a polymerization site by an ethylenically unsaturated monomer compound or the like is underway.
For example, a mixture of a block copolymer and a solid aqueous suspension, where the solid-suspension contains hydraulic binders based on cement, gypsum, lime and hard gypsum, and the block copolymer is represented by the formula A method for dispersing a solid aqueous suspension produced by polymerization of a polyalkylene oxide compound and an ethylenically unsaturated monomer compound is disclosed (for example, see Patent Document 1).
In addition, an aqueous solid-suspended polymer specified as a copolymer in which a block copolymer is produced by atom transfer radical polymerization (ATRP polymerization) and a poly (alkylene oxide) compound and an ethylenically unsaturated monomer compound are copolymerized. Dispersants for suspension are disclosed. (For example, see Patent Document 2.)

Furthermore, a polymer having a (poly) alkylene glycol chain and a structural unit derived from a vinyl monomer, wherein the terminal oxygen atom at at least one of the terminals of the (poly) alkylene glycol chain is an organic residue. There is disclosed a phosphorus atom-containing (poly) alkylene glycol polymer having a structure bonded to a phosphorus atom via (for example, see Patent Document 3).

US Pat. No. 7,425,596 Japanese Patent No. 4399574 JP 2012-131997 A

As a polymer containing a (poly) alkylene glycol chain that can be used as an admixture for cement as described above, a block copolymer having a polymerization site by an ethylenically unsaturated monomer compound or the like is disclosed. However, it has not yet been industrially efficient to supply a product that can sufficiently exhibit the extremely high performance (cement dispersibility (water-reducing), slump flow) that has recently been demanded. Cement dispersibility is a very important factor related to workability in the field of handling cement and strength after hardening of cement, and a cement admixture that realizes a cement composition with better performance is required. .
In particular, there is a demand for a cement admixture that has a simple molecular structure and that can be produced industrially efficiently and that exhibits excellent characteristics.

The present invention has been made in view of the above-described situation, can exhibit performance such as water reduction and workability in cement compositions at a high level, has a simple molecular structure, and is industrially manufactured. An object is to provide a suitable copolymer.

The inventors of the present invention have made various studies on polymers that can be used as cement admixtures having excellent performance such as cement dispersibility (water-reducing properties). As a result, polymer chains (A) composed of unsaturated carboxylic acid monomer units and , A (poly) alkylene glycol block copolymer having a structure in which a polymer chain (B) with a (poly) alkylene glycol structural unit is bonded via a bonding site (X), the polymer chain (A) and the polymer chain (B) have a structure in which the polymer chain (A), the polymer chain (B), and the polymer chain (A) are bonded through the binding site (X) in this order. Copolymers where the binding site (X) does not contain an ester bond (such a copolymer is also referred to as non-ester type) has characteristics such as cement dispersibility (water reduction) and slump flow despite its simple structure. Excellent as a cement admixture Found that the polymer can be used.
In this respect, all the embodiments of the block polymers disclosed in Patent Documents 1 and 2 perform a reaction to modify the end of polyethylene glycol monomethyl ether to an ATRP-macro initiator, and convert t-butyl methacrylate by ATRP polymerization. It polymerizes and acid-decomposes a t-butyl group into carboxyl (-COOH), and an ester bond is included in the bonding site between the polyethylene glycol site and the polymerization site of t-butyl methacrylate. Thus, when an ester bond is included in the block bond site of the block polymer, the block bond portion (ester bond) is rapidly decomposed in an aqueous alkali solution (such a copolymer is also referred to as an ester type). The (poly) alkylene glycol produced by decomposition has almost no cement dispersibility, and the polycarboxylic acid polymer also has a low cement dispersibility. For this reason, the cement dispersibility of the decomposition product is very weak due to hydrolysis, and the amount of addition required for dispersing the cement increases.

Furthermore, these Patent Documents 1 and 2 disclose a structure in which a polyethylene glycol moiety and a polymerized moiety of t-butyl methacrylate are bonded in this order. As in the present invention, the polymer chain (A), the polymer chain are disclosed. A block copolymer bonded in the order of (B) and the polymer chain (A) is not disclosed.

Further, if the bonding site (X) of the (poly) alkylene glycol block copolymer contains a sulfur atom, a copolymer containing no ester bond at the bonding site (X) can be produced by an industrially preferred production method. It has also been found that it can be obtained.
In this respect, all the embodiments of the block polymers disclosed in Patent Documents 1 and 2 are atom transfer radical polymerization (ATRP polymerization), and the phosphorus atom-containing (poly) disclosed in Patent Document 3 Alkylene glycol-based polymers have room for improvement in terms of yield in their production, and have high technical hurdles. In other words, the yield is reduced when phosphorus atoms are introduced, and the polymerization rate is lowered due to a decrease in chain transfer ability due to phosphorus atoms.
In the embodiment described in Patent Document 3, a single-branched phosphorus atom-containing (poly) alkylene glycol polymer is disclosed, but the polymer chain (A) as in the present invention is disclosed. A block copolymer in which the polymer chain (B) and the polymer chain (A) are bonded in this order is not disclosed.

The present invention combines the two elements that the block bond site (X) of the (poly) alkylene glycol block copolymer does not contain an ester bond and contains a sulfur atom. It has been found that it has excellent properties such as cement dispersibility (water reduction) and slump flow despite its simple structure, can be suitably used as a cement admixture, and is a copolymer suitable for industrial production. is there.

That is, in the present invention, the polymer chain (A) based on the unsaturated carboxylic acid monomer unit and the polymer chain (B) based on the (poly) alkylene glycol structural unit are bonded via the binding site (X). A (poly) alkylene glycol block copolymer having an essential structure, wherein the (poly) alkylene glycol block copolymer has a high molecular chain (A) and a high molecular chain (B). It has a structure in which the molecular chain (A), the polymer chain (B), and the polymer chain (A) are bonded in this order via the binding site (X), and the binding site (X) is the polymer chain (B). It is a (poly) alkylene glycol block copolymer that does not form an ester bond with the terminal oxygen atom and contains a sulfur atom.

As a preferred embodiment of the present invention, the (poly) alkylene glycol block copolymer is represented by the following general formula (1):

(In the formula, X ₁ and X ₂ are the same or different and represent an organic residue. AO is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. R ¹ is the same or different. A hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms, wherein R ² , R ³ , R ⁴ , and R ⁵ are each a single unit. In the monomer unit, at least one is —COOM ¹ and the remaining R ² , R ³ , R ⁴ , and R ⁵ are the same or different and are a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or — ( ^{_{CH 2) zCOOM 2 (- (}} CH 2) zCOOM 2 is, COOM ¹ or other _- (CH ²⁾ _zCOOM 2 and anhydride may form a) represents, z are the same or different, 0 Represents an integer of 2. n represents an oxyalkylene group. Represents the average number of moles added, is .m ₁ and _{m 2} is the number of 1 to 500 same or different, .M ¹ and ^{M 2} is the number of 1 to 500 are the same or different, a hydrogen atom, a monovalent Represents a metal, a divalent metal, a trivalent metal, a quaternary ammonium group, or an organic amine group, wherein m ₁ monomer unit bonded via AO and —O—X—; And may be the same as or different from the m ₂ monomer units bonded via —X—.

-O- (AO) n- shown at the center in the general formula (1) is oxygen at the terminal of the (poly) oxyalkylene group constituting the polymer chain (B) by the (poly) alkylene glycol structural unit. Atomic and (poly) oxyalkylene groups. n represents the average number of moles of oxyalkylene groups of the (poly) alkylene glycol structural unit.
X ₁ and X ₂ located on both sides of the (poly) oxyalkylene group are binding sites, and the polymer chain (A) by the unsaturated carboxylic acid monomer unit is (poly) through X ₁ and X _2. It has couple | bonded with the both ends of the polymer chain (B) by the alkylene glycol type | system | group structural unit.
m ₁ and m ₂ represent the average number of moles of unsaturated carboxylic acid monomer units introduced, respectively.
In the present invention, the alkyl group, alkenyl group, organic residue and the like may be linear, branched or cyclic.

As a preferred embodiment of the present invention, a copolymer having a sulfur atom content of 0.15% by mass or more of the entire copolymer, or a 2% by mass aqueous alkaline solution of the copolymer (preferably pH 12.5). Examples thereof include a copolymer having a decomposition rate of 10% by mass or less after 15 minutes in the polymer chain (A) and polymer chain (B).
Hereinafter, the polymer chain (A) based on the unsaturated carboxylic acid monomer unit, the polymer chain (B) based on the (poly) alkylene glycol structural unit, and the binding site (X) will be described in this order.

A combination of two or more preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

<Polymer chain (A) by unsaturated carboxylic acid monomer unit>
In the present invention, the polymer chain (A) based on the unsaturated carboxylic acid monomer unit is a structural unit derived from the unsaturated carboxylic acid monomer. In particular, the unsaturated carboxylic acid monomer unit is preferably a structural unit derived from the following monomer (a) (hereinafter also simply referred to as “monomer (a)”).
Further, the unsaturated carboxylic acid monomer unit is obtained by modifying a structural unit derived from another monomer as long as it is a structural unit having the same structure as that derived from the monomer (a). It may be.
As the monomer (a), for example, the following formula (2):

^{(Wherein, R 2, R 3, R 4} , R 5 , at least one is -COOM ^1, the remaining ^{R 2, R 3, R 4} , R 5 are the same or different, a hydrogen atom, a carbon C 1 -C 10 alkyl _{^{group, - (CH 2) zCOOM 2}} (- (CH 2) zCOOM 2 is, COOM ¹ or other _- (CH 2) _zCOOM may form a ² and anhydride) represents , Z represents an integer of 0 to 2. M ¹ and M ² are the same or different and each represents a hydrogen atom, a monovalent metal, a divalent metal, a trivalent metal, a quaternary ammonium group, or an organic amine group. .) Is preferred.
That is, the monomer (a) is an unsaturated carboxylic acid monomer having at least one carboxyl group bonded to a C═C double bond or a salt thereof (—COOM ¹ ).
The structural unit derived from the monomer (a) is a structure in which a polymerizable double bond of the monomer (a) represented by the general formula (2) is opened by a polymerization reaction (double bond (C = C) corresponds to a single bond (-C—C—).
When the monomer (a) becomes a copolymer represented by the general formula (1), the position of at least one carboxyl group bonded to the C═C double bond or a salt thereof (—COOM ¹ ) is particularly It is not limited. It may be the position of the substituent (R ⁴ , R ⁵ ) bonded to the carbon atom bonded to X ₁ or X ₂ in the general formula (1), or the carbon atom bonded to R ¹ in the general formula (1) It may be the position of the substituent (R ² , R ³ ) bonded to. The position of (—COOM ¹ ) in each monomer unit may be any position of R ² , R ³ , R ⁴ , and R ⁵ .

In the general formula (2), examples of the group represented by M ¹ and M ² include monovalent metal atoms such as alkali metal atoms such as lithium, sodium and potassium; alkaline earth metal atoms such as calcium and magnesium And divalent metal atoms such as aluminum and iron. Moreover, as an organic amine group, alkanolamine groups, such as an ethanolamine group, a diethanolamine group, and a triethanolamine group, a triethylamine group etc. are mentioned, for example.

Specific examples of the unsaturated carboxylic acid monomer represented by the general formula (2) include monocarboxylic acid monomers such as acrylic acid, methacrylic acid, and crotonic acid, maleic acid, itaconic acid, fumaric acid, and methylene. Examples thereof include dicarboxylic acid monomers such as glutaric acid, dicarboxylic acid anhydrides and salts thereof (for example, salts of monovalent metals, divalent metals, trivalent metals, quaternary ammonium or organic amines).
Among these, acrylic acid, methacrylic acid, maleic acid, maleic anhydride and salts thereof are preferable from the viewpoint of polymerizability, and acrylic acid, methacrylic acid and salts thereof are particularly preferable.
Two or more of these monomers may be used in combination.

In the (poly) alkylene glycol block copolymer according to the present invention, the average number of moles of unsaturated carboxylic acid monomer units introduced into the polymer chain (A) by the unsaturated carboxylic acid monomer units is: It is preferably 2 or more, more preferably 4 or more, and further preferably 8 or more. The lower limit of the average number of moles introduced is also preferably 10, more preferably 15, and still more preferably 20. The upper limit is preferably 500, more preferably 300, still more preferably 200, and still more preferably 100.

The average number of moles of unsaturated carboxylic acid monomer units introduced is the number of moles of unsaturated carboxylic acid monomer units contained in 1 mole of the (poly) alkylene glycol block copolymer of the present invention. Mean value. In the general formula (1), the average number of moles of unsaturated carboxylic acid monomer units introduced is represented by m ₁ and m ₂ , and the average number of moles of unsaturated carboxylic acid monomer units introduced is a copolymer. The total value of 2 or more means that the value of m ₁ + m ₂ is 2 or more. In the copolymer of the present invention, it is preferable that the two polymer chains (A) at both ends of the copolymer have a well-balanced length, preferably a substantially uniform length. . For example, it is preferable that the values of m ₁ and m ₂ in the general formula (1) are substantially equal.
When the average number of introduced moles is 2, the unsaturated carboxylic acid monomer unit does not form a polymer chain, but such a case is also included in the polymer chain (A) according to the present invention. Shall.

By setting m to the above preferred number, it becomes possible for the copolymer to sufficiently exhibit the performance based on the polymer chain (A) based on the unsaturated carboxylic acid monomer unit.
In addition, when m exceeds 500, the amount of unsaturated carboxylic acid monomer introduced into the entire copolymer increases, and as a result, the (poly) alkylene glycol structural unit in which cement is dispersed becomes too small. In addition, the cement dispersion performance will be reduced. It is necessary to appropriately set the ratio of the unsaturated carboxylic acid monomer unit to the (poly) alkylene glycol structural unit.
In Examples described later, since methacrylic acid (MAA) is used as the unsaturated carboxylic acid monomer, the average number of moles of unsaturated carboxylic acid monomer units introduced in the polymer chain (A) Is shown by MAA / SH (degree of polymerization of MAA bonded to the thiol end).

In the (poly) alkylene glycol block copolymer according to the present invention, the terminal of the polymer chain (A) not bonded to the bonding site (X) is hydrogen, an alkyl group having 1 to 10 carbon atoms, or 1 to 1 carbon atoms. 10 alkenyl groups are preferred. As described above, in the general formula (1), R ¹ is a portion corresponding to the polymerization termination end of the polymer chain (A) by the unsaturated carboxylic acid monomer unit, and is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. Represents an alkenyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms.

<Polymer chain (B) based on (poly) alkylene glycol structural unit>
Among the polymer chains (B), the structure of the (poly) alkylene glycol (hereinafter referred to as (poly) alkylene glycol is also referred to as PAG) chain is a polymer chain composed of alkylene oxide ((poly) alkylene oxide). I just need it. Preferred is a polymer chain ((poly) alkylene oxide) composed of an alkylene oxide having 2 to 18 carbon atoms.
More preferably, the alkylene oxide is an alkylene oxide having 2 to 8 carbon atoms, such as ethylene oxide, propylene oxide, butylene oxide, isobutylene oxide, 1-butene oxide, 2-butene oxide, trimethylethylene oxide, tetramethylene oxide, tetramethyl. Examples thereof include ethylene oxide, butadiene monooxide, and octylene oxide. In addition, aliphatic epoxides such as dipentane ethylene oxide and dihexane ethylene oxide; alicyclic epoxides such as trimethylene oxide, tetramethylene oxide, tetrahydrofuran, tetrahydropyran, and octylene oxide; aromatics such as styrene oxide and 1,1-diphenylethylene oxide Epoxides and the like can also be used.

The alkylene oxide constituting the (poly) alkylene glycol-based structural unit is preferably appropriately selected according to the use required for the (poly) alkylene glycol-based block copolymer of the present invention. For example, a cement admixture When used for the production of components, it is preferable that a relatively short chain alkylene oxide (oxyalkylene group) having about 2 to 8 carbon atoms is mainly used from the viewpoint of affinity with cement particles. More preferably, the main component is an alkylene oxide having 2 to 4 carbon atoms such as ethylene oxide, propylene oxide, butylene oxide, and still more preferably, the main component is ethylene oxide.

The term “main body” as used herein means that when the polymer chain (B) based on the (poly) alkylene glycol structural unit is composed of two or more types of alkylene oxides, it accounts for the majority of the total number of alkylene oxides present. It means that. When “dominating” is expressed in terms of mol% of ethylene oxide in 100 mol% of all alkylene oxides, 50 to 100 mol% is preferable. Thereby, the (poly) alkylene glycol block copolymer of the present invention has higher hydrophilicity. More preferably, it is 60 mol% or more, More preferably, it is 70 mol% or more, Especially preferably, it is 80 mol% or more, Most preferably, it is 90 mol% or more.

When the polymer chain (B) with the (poly) alkylene glycol structural unit is composed of two or more kinds of alkylene oxides, any form such as random addition, block addition, and alternate addition of two or more kinds of alkylene oxides. May be added.

When the polymer chain (B) by the (poly) alkylene glycol-based structural unit contains an alkylene oxide having 3 or more carbon atoms, the (poly) alkylene glycol-based block copolymer of the present invention has a certain degree of hydrophobicity. Therefore, when the above copolymer is used as a cement admixture, it will bring some structure (network) to the cement particles and reduce the viscosity and stiffness of the cement composition. Can do. On the other hand, if an alkylene oxide having 3 or more carbon atoms is introduced too much, the hydrophobicity of the copolymer becomes too high, and the performance of dispersing cement particles may not be sufficient. For this reason, it is preferable that content of C3 or more alkylene oxide with respect to 100 mass% of all alkylene oxides is 30 mass% or less. More preferably, it is 25 mass% or less, More preferably, it is 20 mass% or less, Most preferably, it is 5 mass% or less.
In addition, depending on the use calculated | required by the said copolymer, the aspect which does not contain C3 or more alkylene oxide may be preferable.

Here, from the viewpoint of improving hydrolysis resistance, an oxyalkylene group having 3 or more carbon atoms may be introduced at the terminal of the polymer chain (B) by the (poly) alkylene glycol structural unit.
Examples of the oxyalkylene group having 3 or more carbon atoms include an oxypropylene group, an oxybutylene group, an oxystyrene group, and an alkyl glycidyl ether residue. Of these, an oxypropylene group and an oxybutylene group are preferable because of ease of production.
When introducing the oxyalkylene group having 3 or more carbon atoms, the amount introduced is preferably adjusted in consideration of the hydrolysis resistance of the binding site (X) in the block copolymer of the present invention. The amount introduced is preferably 50 mol% or more with respect to the polymer chain (B) of the (poly) alkylene glycol structural unit. More preferably, it is 100 mol% or more, More preferably, it is 150 mol% or more, Especially preferably, it is 200 mol% or more.

In the (poly) alkylene glycol block copolymer according to the present invention, the average number of repeating alkylene oxides in the polymer chain (B) by the (poly) alkylene glycol structural unit (average number of moles of oxyalkylene group added) The lower limit may be 1, but is preferably 10, more preferably 20, more preferably 50, still more preferably 75, still more preferably 100, and still more preferably. 150. When the average number of added moles is 1, the (poly) alkylene glycol structural unit is not a polymer chain, but the polymer chain (B) according to the present invention includes such a case. And
The average number of repeating alkylene oxides (average number of added moles of oxyalkylene group) is a polymer chain (B) composed of the (poly) alkylene glycol block unit of the (poly) alkylene glycol block copolymer of the present invention. It means the average value of the number of moles of alkylene oxide added in 1 mole. In the general formula (1), the average number of repeating alkylene oxides is represented by n.
In the present invention, by setting the average addition mole number of oxyalkylene groups to the above-mentioned preferable number, the above-mentioned copolymer can sufficiently exhibit the performance based on the polymer chain (B) by the (poly) alkylene glycol structural unit. Is possible.

The upper limit of the average number of added moles of the oxyalkylene group is not particularly limited, but is preferably 1000, more preferably 800, and even more preferably 500.
When the average added mole number of the oxyalkylene group exceeds the above upper limit, the viscosity of the raw material compound used for producing the copolymer may increase or the reactivity may not be sufficient. There is a possibility that it may not be suitable in terms of workability.
The lower limit of the average addition mole number of the oxyalkylene group is more preferably 25, still more preferably 50, still more preferably 75, and still more preferably 100. As an upper limit, More preferably, it is 400, More preferably, it is 300, More preferably, it is 250, More preferably, it is 200, More preferably, it is 180.

<Binding site (X)>
The binding site (X) in the (poly) alkylene glycol block copolymer of the present invention does not form an ester bond with the terminal oxygen atom of the polymer chain (B) and contains a sulfur atom, Further, it is a site having a structure capable of chemically and stably bonding the polymer chain (A) based on the unsaturated carboxylic acid monomer unit and the polymer chain (B) based on the (poly) alkylene glycol structural unit. The other structures are not particularly limited.
As a preferable structure of the binding site (X), an organic residue derived from a structure serving as a chain transfer agent used in a polymerization reaction can be mentioned.
The structures of the organic residues present at a plurality of positions in the same molecule as the binding site (X) may be the same or different. Further, the structures of organic residues present in different molecules may be the same or different.
In the general formula (1), organic residues as binding sites are indicated by X ₁ and X ₂ .

As the binding site (X) containing the sulfur atom, for example, the following formula (3):

[Wherein, R ⁷ is an organic residue and may be the same or different at two or more binding sites (eg, X ₁ , X ₂ ), preferably a straight chain having 1 to 18 carbon atoms. Or an aromatic group such as a branched alkylene group, phenyl group, alkylphenyl group, pyridinyl group, thiophene, pyrrole, furan, or thiazole (however, a hydroxyl group, an amino group, a cyano group, a carbonyl group, a carboxyl group, a halogen group, And may be partially substituted with a sulfonyl group, a nitro group, a formyl group, etc.))].

R ^{7 in the} structure represented by the above formula (3) is a site bonded to the polymer chain (B) by the (poly) alkylene glycol structural unit, and the sulfur atom (S) is an unsaturated carboxylic acid monomer unit. It is a site | part couple | bonded with the polymer chain (A) by.
As described later, the binding site represented by the above formula (3) is tosylated at the terminal hydroxyl group of the polymer chain (B) with the (poly) alkylene glycol structural unit, thioacetylated with thioacetic acid, and then hydrolyzed. The terminal thiol group thus obtained is used as a chain transfer agent, and the unsaturated carboxylic acid monomer (a) is block-polymerized using a radical polymerization initiator to thereby form a binding site having the structure represented by the above formula (3). Can be formed.

That the bonding site (X) does not form an ester bond with the terminal oxygen atom of the polymer chain (B) means that R ⁷ having the structure represented by the formula (3) is a polymer composed of a (poly) alkylene glycol-based structural unit. Bonded to the terminal oxygen atom of the chain (B), the following formula (4):

(Wherein R ⁷ is the same as described above), but this does not include an ester bond.
In the general formula (1), the bonding sites X ₁ and X ₂ are bonded to the terminal oxygen atom of the (poly) alkylene glycol structural unit of the polymer chain (B), and are represented by the above formula (4). Will be formed.
On the other hand, the copolymer caused a dehydration esterification reaction between the carboxyl group of mercaptocarboxylic acid and the hydroxyl group at the terminal of the polymer chain (B) by the (poly) alkylene glycol structural unit, and thus obtained. When the thiol ester is used as a chain transfer agent and obtained by block polymerization of the unsaturated carboxylic acid monomer (a) using a radical polymerization initiator, the bonding site (X) is represented by the following formula (5):

[Wherein R ⁸ is a mercaptocarboxylic acid residue, such as a linear or branched alkylene group having 1 to 18 carbon atoms, phenyl group, alkylphenyl group, pyridinyl group, thiophene, pyrrole, furan, thiazole, etc. Aromatic group (however, it may be partially substituted with a hydroxyl group, amino group, cyano group, carbonyl group, carboxyl group, halogen group, sulfonyl group, nitro group, formyl group, etc.)]. .
In this case, the bonding site includes the terminal oxygen atom of the polymer chain (B) by the (poly) alkylene glycol structural unit and the following formula (6):

(Wherein R ⁸ is the same as described above), and an ester bond is included at this site.
Such ester bonds are rapidly hydrolyzed in an alkaline aqueous solution, and the performance of the (poly) alkylene glycol block copolymer is not sufficiently exhibited.

The binding site (X) contains a sulfur atom, and thereby, the (poly) alkylene glycol block copolymer of the present invention is efficiently industrially prepared by applying a production method as described later. It is possible to achieve the object of the present invention and solve the problems.
In addition, as a case where the above-mentioned binding site (X) has a structure that does not form an ester bond with the terminal oxygen atom of the polymer chain (B), a binding site derived from a residue containing a phosphorus atom can be mentioned. Therefore, it is difficult to efficiently provide a (poly) alkylene glycol block copolymer.

<(Poly) alkylene glycol block copolymer>
As a preferred form of the (poly) alkylene glycol block copolymer of the present invention, the sulfur atom content is 0.15% by mass or more of the whole copolymer. That is, when the total amount of the copolymer is 100% by mass, the sulfur atom content is preferably 0.15% by mass or more, more preferably 0.2% by mass or more, and still more preferably 0.8%. 3% by mass or more. Moreover, it is preferable that content of a sulfur atom will be 15 mass% or less, More preferably, it is 10 mass% or less, More preferably, it is 5 mass% or less.
The content of sulfur atoms is the content of sulfur atoms in the PAG dithiol compound (number of SH introduced per molecule of PAG dithiol compound in the examples described later), unsaturated carboxylic acid monomer units in the polymer chain (A) It can be calculated from the average value of the number of one thiol group (SH) (MAA number / SH in Examples described later).
When the content of the sulfur atom is within the above range, the (poly) alkylene glycol block copolymer of the present invention can be efficiently produced by the production method described later.

As a preferred form of the (poly) alkylene glycol block copolymer of the present invention, the polymer chain (A) and polymer chain (B) after 15 minutes in a 2% by weight alkaline aqueous solution of the copolymer are also included. Is a decomposition rate of 10% by mass or less. More preferably, it is 5 mass% or less, More preferably, it is 2 mass% or less. Most preferably, it is substantially 0% by mass.
The degradation rate here means the hydrolysis rate in an alkaline aqueous solution, and if the hydrolysis rate is within the above range, superior performance in cement dispersibility (water reduction), slump flow, etc. In addition, workability and the like in cement admixture applications are improved.

For example, the decomposition rate can be measured by the following hydrolysis test.
(1) The weight average molecular weight (Mw) of the copolymer is measured under the GPC measurement conditions described later, and is defined as the molecular weight before the reaction (before decomposition).
(2) The copolymer is dissolved in an aqueous NaOH solution to prepare a 2% by mass aqueous solution. At that time, the pH of the NaOH aqueous solution is adjusted in advance so that the pH of the aqueous solution becomes 12.5. The 2% aqueous solution is stirred for 15 minutes and then neutralized with a 35% aqueous HCl solution to bring the pH to 5.0.
The copolymer is taken out, and its weight average molecular weight (Mw) is measured under the GPC measurement conditions described later to obtain a molecular weight after reaction (after decomposition).
(3) The hydrolysis rate is calculated from the GPC chart before and after the reaction.

The polymer chain (A) based on the unsaturated carboxylic acid monomer unit and the polymer chain (B) based on the (poly) alkylene glycol structural unit are polymer chains (A), polymer chains (B), high Among the (poly) alkylene glycol block copolymers according to the present invention that require a structure in which the molecular chain (A) is bonded via the bonding site (X) in this order, a particularly preferable structure is represented by the following formula (7). ).

In the formula, R ² is the same or different and represents a hydrogen atom or a methyl group. n represents the average addition mole number of an oxyethylene group, and is a number of 1 to 500 (preferably a number of 75 to 500). m ₁ and m ₂ are the same or different and have a number of 1 to 500 (preferably a number of 20 to 500).
In the above structure, the unsaturated carboxylic acid monomer is acrylic acid or methacrylic acid, the (poly) alkylene glycol chain is a (poly) ethylene glycol chain, and the binding site (X) is sulfur derived from thioacetic acid or a metal salt thereof. A structure that is a bonding site containing an atom is preferable.

In the above formula (7), the positions of the R ² and COOH groups of the unsaturated carboxylic acid monomer units are drawn on the terminal hydrogen atom side, but the R ² and COOH groups of each monomer unit The position may be located on the sulfur atom side. In the structure represented by the above formula (7), it is randomly determined for each monomer unit whether the position of R ² and the COOH group is on the hydrogen atom side or on the sulfur atom side.

The (poly) alkylene glycol block copolymer of the present invention has a weight average molecular weight (Mw) in consideration of its handleability and the retention of the cement composition when the polymer is used for cement admixture. ) Is preferably 1,000,000 or less. More preferably, it is 500,000 or less, More preferably, it is 300,000 or less, More preferably, it is 200,000 or less, More preferably, it is 150,000 or less, More preferably, it is 100,000 or less, More preferably, it is 50,000 or less. Further, when used for cement admixture, it is preferable that Mw is 1000 or more from the viewpoint that performance is better when adsorbed to cement particles to some extent, and the adsorption power increases as Mw increases. More preferably, it is 2000 or more, More preferably, it is 3000 or more, Especially preferably, it is 4000 or more, Most preferably, it is 5000 or more.
The number average molecular weight (Mn) is preferably 500,000 or less. More preferably, it is 250,000 or less, More preferably, it is 150,000 or less, More preferably, it is 100,000 or less, More preferably, it is 75,000 or less, More preferably, it is 35,000 or less. Moreover, it is preferable that it is 1000 or more. More preferably, it is 2000 or more, More preferably, it is 3000 or more, Especially preferably, it is 4000 or more, Most preferably, it is 5000 or more.
In addition, the weight average molecular weight and number average molecular weight of a compound can be calculated | required by the gel permeation chromatography (GPC) analysis method mentioned later.

<Method for producing (poly) alkylene glycol block copolymer>
As an example of the method for producing the (poly) alkylene glycol block copolymer according to the present invention, a copolymer having a binding site containing a sulfur atom derived from thioacetic acid (or a metal salt thereof) will be described below. explain.

The (poly) alkylene glycol block copolymer according to the present invention provides a polymer chain (B) with a (poly) alkylene glycol structural unit having hydroxyl group ends at both ends, A step of performing a tosylation reaction (tosylation step), a step of reacting thioacetic acid or a metal salt thereof (thioacetylation step), a step of hydrolyzing the thioacetyl group obtained by the thioacetylation step (hydrolysis) Decomposition step), polymer chain (B) with (poly) alkylene glycol structural units having thiol groups at both ends as a chain transfer agent and block polymerization of unsaturated carboxylic acid monomer using radical polymerization initiator It can manufacture by performing the process (block polymerization process) to make.
A method for producing such a (poly) alkylene glycol block copolymer is also one aspect of the present invention.
The polymer chain (B) composed of (poly) alkylene glycol structural units having thiol groups at both ends is also referred to as a PAG dithiol compound. When (poly) alkylene glycol is (poly) ethylene glycol, it is also called a PEG dithiol compound.

<Tosylation process>
In the tosylation step, the tosyl group is formed by reacting the hydroxyl group terminal of a polymer chain (preferably (poly) alkylene glycol) having a hydroxyl group terminal at both ends with a tosylating agent. To obtain a polymer chain (preferably both-terminal tosylated (poly) alkylene glycol) having a tosylated (poly) alkylene glycol structural unit at both ends.
The tosylating agent used in the tosylation step and the reaction conditions are not particularly limited as long as the hydroxyl group can be tosylated. For example, tosyl chloride (TsCl) is used as a tosylating agent and dichloromethane (CH ₂ Cl ₂ ) is reacted. What is necessary is just to set reaction conditions suitably as a solvent.

<Thioacetylation process>
In the thioacetylation step, the tosyl group of the polymer chain obtained by the (poly) alkylene glycol structural unit having a tosyl group at both ends obtained by the tosylation step and having a tosyl group at both ends is combined with the thioacetylating agent. A thioacetyl group is generated by reaction to obtain a polymer chain (preferably thioacetylated (poly) alkylene glycol) with a thioacetylated (poly) alkylene glycol structural unit.
The thioacetylating agent used in the thioacetylating step and the reaction conditions are not particularly limited as long as the tosyl group can be thioacetylated. For example, potassium thioacetate (CH ₃ COSK) is used as the thioacetylating agent, and acetonitrile (CH ₃ CN) is used. May be used as a reaction solvent, and reaction conditions may be set as appropriate.

<Hydrolysis step>
In the hydrolysis step, the thioacetyl group of the polymer chain is hydrolyzed by a (poly) alkylene glycol structural unit having a thioacetyl group at both ends obtained by thioacetylation at the both ends, obtained by the thioacetylation step. A group is generated to obtain a polymer chain (preferably dithiolated (poly) alkylene glycol) with a dithiolated (poly) alkylene glycol-based structural unit. For example, a PAG dithiol compound represented by the following formula (8) can be obtained.
The PAG dithiol compound represented by the following formula (8) is preferable as an intermediate for producing the (poly) alkylene glycol block copolymer according to the present invention.
Also in the hydrolysis step, the reaction conditions may be set as appropriate so that the hydrolysis of the thioacetyl group proceeds.

In the formula, R ⁷ , AO and n are the same as described above.

The PAG dithiol compound has a weight average molecular weight (Mw) of 500,000 or less, considering its handleability and the viscosity of the cement composition when a polymer produced using the compound is used for cement admixture. It is preferable that More preferably, it is 300,000 or less, More preferably, it is 100,000 or less, Especially preferably, it is 50,000 or less, Most preferably, it is 30,000 or less. Moreover, when using for a cement admixture use, it is preferable that Mw is 100 or more from a viewpoint that the one where Mw is large to some extent becomes dispersible. More preferably, it is 300 or more, More preferably, it is 500 or more, Especially preferably, it is 1000 or more, Most preferably, it is 2000 or more.
The number average molecular weight (Mn) is preferably 500,000 or less. More preferably, it is 300,000 or less, More preferably, it is 100,000 or less, Especially preferably, it is 50,000 or less, Most preferably, it is 30,000 or less. Moreover, it is preferable that it is 100 or more. More preferably, it is 300 or more, More preferably, it is 500 or more, Especially preferably, it is 1000 or more, Most preferably, it is 2000 or more.
In addition, the weight average molecular weight and number average molecular weight of a compound can be calculated | required by the gel permeation chromatography (GPC) analysis method mentioned later.

The PAG dithiol compound has a mercapto group derived from thioacetic acid or a metal salt thereof, and thus acts as a chain transfer agent for radical polymerization reaction. Various polymers produced using radical polymerization reaction are produced. Can be suitably used.

<Block polymerization process>
As described above, the PAG dithiol compound has a function as a chain transfer agent. Using this compound as a chain transfer agent, the polymer chain (A) ( Preferably, the (poly) alkylene glycol block copolymer of the present invention is conveniently and efficiently produced at low cost by radical polymerization of the unsaturated carboxylic acid monomer component containing the monomer (a)). Can be manufactured.
The unsaturated carboxylic acid monomer component is preferably mainly composed of the unsaturated carboxylic acid monomer that forms the polymer chain (A), and substantially all forms the polymer chain (A). It is preferably an unsaturated carboxylic acid monomer.

When a polymer is produced using the PAG dithiol compound represented by the general formula (8) as a chain transfer agent, the unsaturated carboxylic acid monomer component is present via the sulfur atom (S) of the PAG dithiol compound. One after another is added to form a polymer portion, and the polymer thus formed is produced as a main component.

In the polymerization reaction, a normal chain transfer agent may be used in combination. Examples of chain transfer agents that can be used include thiol chain transfer agents such as mercaptoethanol, thioglycerol, thioglycolic acid, 3-mercaptopropionic acid, thiomalic acid, and 2-mercaptoethanesulfonic acid; secondary such as isopropyl alcohol Alcohol; phosphorous acid, hypophosphorous acid and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, hydrogen sulfite, dithionite, metabisulfite and salts thereof (sodium sulfite, hydrogen sulfite) And hydrophilic chain transfer agents such as lower oxides of sodium, sodium dithionite, sodium metabisulfite, and the like, and salts thereof.

A hydrophobic chain transfer agent can also be used as the chain transfer agent. Examples of the hydrophobic chain transfer agent include 3 carbon atoms such as butanethiol, octanethiol, decanethiol, dodecanethiol, hexadecanethiol, octadecanethiol, cyclohexyl mercaptan, thiophenol, octyl thioglycolate, and octyl 3-mercaptopropionate. A thiol chain transfer agent having the above hydrocarbon group is preferably used.

When the chain transfer agent is used in addition to the PAG dithiol compound, the amount used may be set as appropriate, but is preferably 0.1 mol or more with respect to 100 mol of the total amount of unsaturated carboxylic acid monomer components. More preferably, it is 0.25 mol or more, more preferably 0.5 mol or more, and preferably 20 mol or less, more preferably 15 mol or less, still more preferably 10 mol or less.

In order to improve the polymerization rate of the monomer (a), it is important to appropriately set the neutralization rate of the carboxyl group of the monomer (a). In order to improve the polymerization rate of the monomer (a), it is preferable not to neutralize the carboxyl group as much as possible. However, when the neutralization rate of the carboxyl group is low, the acid type carboxyl group and the oxygen atom of the (poly) alkylene glycol structural unit may form a hydrogen bond to form a water-insoluble intermediate. The polymerization rate of the monomer (a) may decrease. Moreover, when the neutralization rate of the carboxyl group of the monomer (a) is increased too much, the polymerizability of the monomer (a) decreases, and as a result, the polymerization rate of the monomer (a) decreases. .
The neutralization rate of the carboxyl group of the monomer (a) is preferably 0 to 100 mol%, more preferably 10 to 80 mol%, still more preferably 20 to 60 mol%.

The polymerization reaction can be performed by a method such as solution polymerization or bulk polymerization using a radical polymerization initiator as necessary. The solution polymerization can be performed batchwise, continuously, or a combination thereof. Examples of the solvent used in this case include water; alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; benzene, toluene, Aromatic or aliphatic hydrocarbons such as xylene, cyclohexane and n-hexane; ester compounds such as ethyl acetate; ketone compounds such as acetone and methyl ethyl ketone; cyclic ether compounds such as tetrahydrofuran and dioxane. Among them, for example, when used in an application that is often used as an aqueous solution such as a cement admixture, polymerization is preferably performed by an aqueous solution polymerization method.

Among the solution polymerizations described above, in aqueous solution polymerization, it is preferable to use a water-soluble radical polymerization initiator because it is not necessary to remove insoluble components after polymerization. For example, persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate; hydrogen peroxide; azoamidine compounds such as 2,2′-azobis-2-methylpropionamidine hydrochloride, 2,2′-azobis-2- Cyclic azoamidine compounds such as (2-imidazolin-2-yl) propane hydrochloride, azonitrile compounds such as 2-carbamoylazoisobutyronitrile, 2,4′-azobis {2-methyl-N- [2- (1- Water-soluble azo initiators such as azoamide compounds such as (hydroxybutyl)] propionamide}, macroazo compounds such as esters of 4,4′-azobis (4-cyanovaleric acid) and (alkoxy) polyethylene glycol, These 1 type (s) or 2 or more types can be used. Of these, azoamidine compound-based initiators are preferred.

At this time, alkali metal sulfite such as sodium hydrogen sulfite, metabisulfite, sodium hypophosphite, Fe (II) salt such as molle salt, hydroxymethanesulfinate sodium dihydrate, hydroxylamine hydrochloride, thiourea , L-ascorbic acid (salt), erythorbic acid (salt) and other accelerators (reducing agents) can be used in combination. For example, a combination of hydrogen peroxide and an organic reducing agent is possible. Examples of the organic reducing agent include L-ascorbic acid (salt), L-ascorbic acid ester, erythorbic acid (salt), erythorbic acid ester, and the like. It can be used suitably. These radical polymerization initiators and accelerators (reducing agents) may be used alone or in combination of two or more.
The amount of the accelerator (reducing agent) used is not particularly limited. For example, when the total amount of the polymerization initiator used in combination is 100 mol, it is preferably 10 mol or more, more preferably 20 mol or more. More preferably, it is 50 mol or more, preferably 1000 mol or less, more preferably 500 mol or less, still more preferably 400 mol or less.

In solution polymerization and bulk polymerization using lower alcohols, aromatic or aliphatic hydrocarbons, esters or ketones as solvents, radical polymerization initiators such as benzoyl peroxide, lauroyl peroxide, sodium peroxide, etc. Peroxides such as t-butyl hydroperoxide and cumene hydroperoxide; azonitrile compounds such as azobisisobutyronitrile, 2,4′-azobis {2-methyl-N- [2- (1- 1 or 2 of azo initiators such as azoamide compounds such as hydroxybutyl)] propionamide}, macroazo compounds such as esters of 4,4′-azobis (4-cyanovaleric acid) and (alkoxy) polyethylene glycol More than seeds can be used. Among these, an azo initiator is suitable as will be described later. In this case, an accelerator such as an amine compound can be used in combination.
Furthermore, when using a mixed solvent of water and a lower alcohol, it can be appropriately selected from the above-mentioned various radical polymerization initiators or a combination of the above radical polymerization initiator and accelerator.

The amount of the radical polymerization initiator used may be appropriately set according to the form and amount of the PAG dithiol compound and the unsaturated carboxylic acid monomer component, but the unsaturated carboxylic acid that the radical polymerization initiator serves for polymerization. If the amount is too small relative to the monomer component, the radical concentration may be too low and the polymerization reaction may be slowed.On the other hand, if the amount is too large, the radical concentration will be too high, which is less than the polymerization reaction caused by sulfur atoms. The polymerization reaction from the saturated carboxylic acid monomer component has priority, and the yield of the (poly) alkylene glycol block copolymer of the present invention may not be increased. Therefore, the amount of the radical polymerization initiator used is preferably 0.001 mol or more, more preferably 0.01 mol or more, and still more preferably 0.001 mol or more with respect to 100 mol of the total amount of unsaturated carboxylic acid monomer components. 1 mol or more, particularly preferably 0.2 mol or more, more particularly preferably 0.5 mol or more, most preferably 1 mol or more, preferably 50 mol or less, more preferably 20 mol or less, still more preferably 15 moles or less, even more preferably 10 moles or less, particularly preferably 5 moles or less, and most preferably 3 moles or less.

In the above polymerization reaction, the polymerization conditions such as the polymerization temperature are appropriately determined depending on the polymerization method used, the solvent, the polymerization initiator, and the chain transfer agent, but the polymerization temperature is preferably 0 ° C. or higher, It is preferable that it is 150 degrees C or less. More preferably, it is 30 degreeC or more, More preferably, it is 50 degreeC or more. More preferably, it is 120 degrees C or less, More preferably, it is 100 degrees C or less.

The method for charging the unsaturated carboxylic acid monomer component into the reaction vessel is not particularly limited, and a method in which the entire amount is initially charged into the reaction vessel at once; a method in which the entire amount is divided or continuously charged into the reaction vessel Any of the methods in which a part is initially charged into the reaction vessel and the remainder is divided or continuously charged into the reaction vessel may be employed. The radical polymerization initiator and 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. The alkylene glycol block copolymer is produced by a method in which the entire amount of the PAG dithiol compound is initially charged into a reaction vessel at an initial stage, and then an unsaturated carboxylic acid monomer component is continuously charged therein. It is preferable. When produced by such a method, the fluidity of the cement can be further improved when the resulting polymer is used as a cement admixture.

In the above polymerization reaction, in order to obtain a polymer having a predetermined molecular weight with good reproducibility, it is preferable to allow the polymerization reaction to proceed stably. Therefore, in the solution polymerization, the dissolved oxygen concentration at 25 ° C. of the solvent to be used is set to a range of 5 ppm or less (preferably 0.01 to 4 ppm, more preferably 0.01 to 2 ppm, still more preferably 0.01 to 1 ppm). It is preferable to do. In addition, when performing nitrogen substitution after adding an unsaturated carboxylic acid monomer component to the solvent, the dissolved oxygen concentration of the system including the unsaturated carboxylic acid monomer component is within the above range. Is appropriate.

The dissolved oxygen concentration of the solvent may be adjusted in a polymerization reaction tank, or a dissolved oxygen amount may be adjusted in advance. Examples of the method for driving off oxygen in the solvent include the following methods (1) to (5).
(1) After pressure-filling an inert gas such as nitrogen in a sealed container containing a solvent, the partial pressure of oxygen in the solvent is lowered by lowering the pressure in the sealed container. In that case, you may reduce the pressure in a sealed container under 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) An inert gas such as nitrogen is bubbled in the solvent in the container for a long time.
(4) The solvent is once boiled and then cooled in an inert gas atmosphere such as nitrogen.
(5) A static mixer (static mixer) is installed in the middle of the pipe, and an inert gas such as nitrogen is mixed in the pipe for transferring the solvent to the polymerization reaction tank.

The polymer obtained by the above polymerization reaction is easy to handle by adjusting it to a pH range of weak acid or higher (preferably pH 4 or higher, more preferably pH 5 or higher, particularly preferably pH 6 or higher) in an aqueous solution state. be able to.
On the other hand, when the polymerization reaction is carried out at a pH of 7 or more, the polymerization rate is lowered, and at the same time, the copolymerizability is not sufficient. is there. Therefore, in the polymerization reaction, it is preferable to perform the polymerization reaction in a pH range from acidic to neutral (preferably less than pH 6, more preferably less than pH 5.5, and still more preferably less than pH 5). Examples of preferable polymerization initiators that change the polymerization system from acidic to neutral include persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate, and azoamidine compounds such as azobis-2-methylpropionamidine hydrochloride. It is preferable to use a water-soluble azo initiator such as hydrogen peroxide, a combination of hydrogen peroxide and an organic reducing agent, or the like.

In addition to the (poly) alkylene glycol block copolymer, the reaction product obtained by the above polymerization reaction may contain various polymers as by-products, unreacted raw materials, and impurities contained in the raw materials. Therefore, if necessary, it may be subjected to a step of isolating individual polymers, but it is usually used in various applications without isolating individual polymers from the viewpoint of work efficiency and production cost. May be used.
A preferable reaction form of each step in the production method, that is, a tosylation step, a thioacetylation step, a hydrolysis step, and a block polymerization step is represented by the following formula.
In the following formulae, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁷ , m ₁ , m ₂ , and n are the same as described above.

<(Poly) alkylene glycol block copolymer, dispersant, cement admixture, and cement composition>
The (poly) alkylene glycol block copolymer of the present invention can be suitably used for various applications such as an adhesive, a sealing agent, a component for imparting flexibility to various polymers, and a detergent builder. In a composition containing inorganic fine particles such as cement and gypsum, it can also be suitably used as a dispersant for dispersing inorganic fine particles.
Such a dispersant containing the (poly) alkylene glycol block copolymer of the present invention is also one aspect of the present invention.
Among them, the (poly) alkylene glycol block copolymer of the present invention can exhibit extremely high cement dispersion performance as described above, and is therefore preferably used for cement admixture. Thus, the cement admixture containing the (poly) alkylene glycol block copolymer is also one aspect of the present invention.
The cement admixture can be used in addition to a cement composition such as cement paste, mortar, concrete, etc., and such a cement composition containing the cement admixture is also one aspect of the present invention. Furthermore, a cement composition containing the cement admixture, cement and water is also one aspect of the present invention.

As the above-mentioned cement composition, those containing cement, water, fine aggregate, coarse aggregate and the like are suitable. As the cement, Portland cement (ordinary, early strength, very early strength, moderate heat, sulfate resistance, Various mixed cements (blast furnace cement, silica cement, fly ash cement); white Portland cement; alumina cement; super fast cement (1 clinker fast cement, 2 clinker fast cement, magnesium phosphate cement) ); Grout cement; oil well cement; low exothermic cement (low exothermic blast furnace cement, fly ash mixed low exothermic blast furnace cement, high content of belite); ultra high strength cement; cement-based solidified material; ecocement (city waste) Cement produced from one or more of incineration ash and sewage sludge incineration ash G) other such, these blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica fume, silica powder, and a film obtained by adding a fine powder and gypsum limestone powder.
As the above aggregate, in addition to gravel, crushed stone, granulated slag, recycled aggregate, etc., siliceous, clay, zircon, high alumina, silicon carbide, graphite, chrome, chromic, magnesia, etc. Refractory aggregate and the like.

Examples of the unit water amount per 1 m ³ of the cement composition, the cement use amount, and the water / cement ratio (mass ratio) include, for example, a unit water amount of 100 to 185 kg / m ³ , a use cement amount of 200 to 800 kg / m ³ , and a water / cement ratio. The cement ratio (mass ratio) is preferably 0.1 to 0.7, and more preferably, the unit water amount is 120 to 175 kg / m ³ , the cement amount used is 250 to 800 kg / m ³ , and the water / cement ratio ( (Mass ratio) = 0.2 to 0.65. Thus, the cement admixture containing the (poly) alkylene glycol block copolymer of the present invention can be used in a wide range from poor blending to rich blending, and has a high water reduction rate range, that is, water / Cement ratio (mass ratio) = 0.15 to 0.5 (preferably 0.15 to 0.4) can be used even in a region where the water / cement ratio is low. Is effective for both high-strength concrete with a small amount and poor blend concrete with a unit cement amount of 300 kg / m ³ or less.

As the cement admixture of the present invention, the fluidity, retention and workability can be exhibited with high performance in a balanced manner even in a high water reduction rate region, and since it has excellent workability, ready-mixed concrete, concrete secondary products ( It can be used effectively for precast concrete), centrifugal concrete, vibration compaction concrete, steam-cured concrete, shotcrete, etc., and medium fluidity concrete (slump value is 22-25cm) Mortar and concrete that require high fluidity, such as concrete with high fluidity (concrete with a slump value of 25 cm or more and a slump flow value of 50 to 70 cm), self-filling concrete, self-leveling material, etc. Also effective.

When the cement admixture is used in the cement composition, the blending ratio thereof is the essential component of the present invention (poly) alkylene glycol block copolymer is 100% by mass of the total mass of cement in terms of solid content. It is preferable to set so that it may become 0.01-10 mass% with respect to. If it is less than 0.01% by mass, the performance may not be sufficient. On the other hand, if it exceeds 10% by mass, the effect will substantially reach its peak, which may be disadvantageous in terms of economy. More preferably, it is 0.02-8 mass%, More preferably, it is 0.05-6 mass%.

The cement admixture can also be used in combination with other cement additives. As another cement additive, 1 type (s) or 2 or more types, such as a cement additive (material) as shown below, can be used, for example. Among these, it is particularly preferable to use an oxyalkylene antifoaming agent or an AE agent in combination.
In addition, it is suitable for the addition ratio of a cement additive to be 0.0001-10 mass parts with respect to 100 mass parts of solid content of the said (poly) alkylene glycol type block copolymer.

(1) Water-soluble polymer substances: polyacrylic acid (sodium), polymethacrylic acid (sodium), polymaleic acid (sodium), unsaturated carboxylic acid polymer such as sodium salt of acrylic acid / maleic acid copolymer; polyethylene Polymers of polyoxyethylene or polyoxypropylene such as glycol and polypropylene glycol or copolymers thereof; Nonionic cellulose ethers such as methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, carboxyethylcellulose, hydroxypropylcellulose, etc. Yeast glucan, xanthan gum, β-1,3 glucans (both linear and branched), for example, curdlan, paramylon, pachyman, Polyacrylamide; polyvinyl alcohol; starch; starch phosphate ester; sodium alginate; gelatin; copolymer of acrylic acid having an amino group in the molecule and its four Grade compounds and the like.

(2) Polymer emulsion.
(3) Retardant: Gluconic acid, malic acid or citric acid, and oxycarboxylic acids such as inorganic salts or organic salts such as sodium, potassium, calcium, magnesium, ammonium, triethanolamine, and salts thereof; glucose , Fructose, galactose, saccharose; sugar alcohols such as sorbitol; magnesium silicate; phosphoric acid and its salts or borate esters; aminocarboxylic acid and its salts; alkali-soluble protein; humic acid; tannic acid; Polyhydric alcohols such as aminotri (methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid) and alkali metal salts thereof, al Phosphonic acids and derivatives thereof such as Li earth metal salts.

(4) Early strengthening agent / accelerator: soluble calcium salt such as calcium chloride, calcium nitrite, calcium nitrate, calcium bromide, calcium iodide; alkanolamine; alumina cement; calcium aluminate silicate.
(5) Mineral oil-based antifoaming agent: cocoon oil, liquid paraffin, etc.
(6) Fat and oil-based antifoaming agents: animal and vegetable oils, sesame oil, castor oil, alkylene oxide adducts thereof and the like.
(7) Fatty acid-based antifoaming agent: oleic acid, stearic acid, and these alkylene oxide adducts.
(8) Fatty acid ester antifoaming agent: glycerin monoricinoleate, alkenyl succinic acid derivative, sorbitol monolaurate, sorbitol trioleate, natural wax and the like.

(9) Oxyalkylene antifoaming agents: polyoxyalkylenes such as (poly) oxyethylene (poly) oxypropylene adducts; diethylene glycol heptyl ether, polyoxyethylene oleyl ether, polyoxypropylene butyl ether, polyoxyethylene polyoxypropylene (Poly) oxyalkyl ethers such as 2-ethylhexyl ether and higher alcohols having 12 to 14 carbon atoms such as oxyethyleneoxypropylene adducts; (poly) oxy such as polyoxypropylene phenyl ether and polyoxyethylene nonylphenyl ether Alkylene (alkyl) aryl ethers; 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,5-dimethyl-3-hexyne-2,5-diol, 3-methyl-1 -Bu Acetylene ethers obtained by addition polymerization of alkylene oxide to acetylene alcohol such as n-3-ol; (poly) oxyalkylene fatty acid esters such as diethylene glycol oleate, diethylene glycol laurate, ethylene glycol distearate; polyoxyethylene (Poly) oxyalkylene sorbitan fatty acid esters such as sorbitan monolaurate and polyoxyethylene sorbitan trioleate; (poly) oxyalkylene alkyl such as sodium polyoxypropylene methyl ether sulfate and sodium polyoxyethylene dodecylphenol ether sulfate ( Aryl) ether sulfate esters; (poly) oxyethylene stearyl phosphates, etc. Polyoxyalkylene alkyl phosphoric acid esters; polyoxyethylene such as polyoxyethylene lauryl amine (poly) oxyalkylene alkyl amines; polyoxyalkylene amide.

(10) Alcohol-based antifoaming agent: octyl alcohol, hexadecyl alcohol, acetylene alcohol, glycols and the like.
(11) Amide antifoaming agent: acrylate polyamine and the like.
(12) Phosphate ester antifoaming agent: tributyl phosphate, sodium octyl phosphate, etc.
(13) Metal soap type antifoaming agent: aluminum stearate, calcium oleate, etc.
(14) Silicone antifoaming agent: dimethyl silicone oil, silicone paste, silicone emulsion, organically modified polysiloxane (polyorganosiloxane such as dimethylpolysiloxane), fluorosilicone oil and the like.
(15) AE agent: resin soap, saturated or unsaturated fatty acid, sodium hydroxystearate, lauryl sulfate, ABS (alkyl benzene sulfonic acid), LAS (linear alkyl benzene sulfonic acid), alkane sulfonate, polyoxyethylene alkyl (phenyl) ether , Polyoxyethylene alkyl (phenyl) ether sulfate or a salt thereof, polyoxyethylene alkyl (phenyl) ether phosphate or a salt thereof, protein material, alkenyl sulfosuccinic acid, α-olefin sulfonate, and the like.

(16) Other surfactants: aliphatic monohydric alcohols having 6 to 30 carbon atoms in the molecule such as octadecyl alcohol and stearyl alcohol, and those having 6 to 30 carbon atoms in the molecule such as abiethyl alcohol Intramolecular such as alicyclic monohydric alcohol, dodecyl mercaptan, etc. Intramolecular such as monovalent mercaptan having 6-30 carbon atoms in the molecule, such as nonylphenol, alkylphenol having 6-30 carbon atoms in the molecule, dodecylamine, etc. 10 mol or more of an alkylene oxide such as ethylene oxide or propylene oxide was added to a carboxylic acid having 6 to 30 carbon atoms in the molecule such as an amine having 6 to 30 carbon atoms, lauric acid or stearic acid. Polyalkylene oxide derivatives; having an alkyl group or alkoxyl group as a substituent Alkyl diphenyl ether sulfonates in which two phenyl groups having a sulfone group are ether-bonded; various anionic surfactants; various cationic surfactants such as alkylamine acetate and alkyltrimethylammonium chloride; various nonions Surfactants; various amphoteric surfactants.
(17) Waterproofing agent: fatty acid (salt), fatty acid ester, oil and fat, silicon, paraffin, asphalt, wax and the like.
(18) Rust preventive: nitrite, phosphate, zinc oxide and the like.
(19) Crack reducing agent: polyoxyalkyl ethers; alkanediols such as 2-methyl-2,4-pentanediol.
(20) Expansion material: Ettlingite, coal, etc.

Other cement additives (materials) include, for example, cement wetting agents, thickeners, separation reducing agents, flocculants, drying shrinkage reducing agents, strength enhancing agents, self-leveling agents, rust preventives, colorants, antifungal agents , Blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica fume, silica powder, gypsum and the like.

The (poly) alkylene glycol block copolymer of the present invention is composed of the above-mentioned constitution, and has excellent performance such as cement dispersibility (water reduction) and slump flow, and has excellent workability, etc., so that inorganic fine particles are dispersed. As a dispersant to be used, it can be suitably used for cement admixture and the like. Furthermore, the molecular structure is simple due to the block structure, and it is suitable for industrial production.

FIG. 1 is a graph showing the results of mortar tests in Examples and Comparative Examples, in which the horizontal axis represents MAA / SH and the vertical axis represents the addition ratio with the copolymer 1. FIG. 2 shows hydrolysis test results in Examples and Comparative Examples, and conceptually shows GPC charts before and after the test.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by mass” and “%” means “% by mass”.

Various measurements in the examples were performed as follows.
<GPC analysis method>
Device: Waters Alliance (2695)
Analysis software: Waters, Empor professional + GPC option Column: Tosoh Co., Ltd., TSK guard columns SWXL + TSKgel G4000SWXL + G3000SWXL + G2000SWXL
Detector: differential refractometer (RI) detector (Waters 2414), multi-wavelength visible ultraviolet (PDA) detector (Waters 2996)
Eluent: A solution prepared by dissolving 115.6 g of sodium acetate trihydrate in a mixed solvent of 10999 g of water and 6001 g of acetonitrile, and further adjusting the pH to 6.0 with acetic acid. ) 272500, 219300, 107000, 50000, 24000, 12600, 7100, 4250, 1470)
Calibration curve: Prepared by a cubic equation based on the Mp value and elution time of the polyethylene glycol.
Flow rate: 1 mL / min Column temperature: 40 ° C
Measurement time: 45 minutes Sample solution injection amount: 100 μL
Sample concentration: adjusted to 1% with eluent.

<LC analysis method>
Device: Waters Alliance (2695)
Analysis software: Waters Emper professional + GPC option column: Waters Atlantis dC18 guard column + column (particle size 5 μm, inner diameter 4.6 mm × 250 mm × 2)
Detector: differential refractometer (RI) detector (Waters 2414), multi-wavelength visible ultraviolet (PDA) detector (Waters 2996)
Eluent: A mixture of acetonitrile / 100 mM acetate ion exchange aqueous solution = 40/60 (mass%) adjusted to pH 4.0 by adding 30% NaOH aqueous solution Flow rate: 1 mL / min Column temperature: 40 ° C.
Measurement time: 45 minutes Sample solution injection amount: 100 μL
Sample concentration: adjusted to 1% with eluent.

<CE analysis method>
Equipment: Beckman Coulter MDQ analysis software: 32 Karat
Capillary used: Silica tube, 50 cm Effective Length, 75 μm D, 375 μm
O. D
Eluent: Boric acid (1.546 g) dissolved in ion-exchanged water (498.45 g) Detector: UV voltage: 20 kV
Capillary temperature: 25 ° C
Measurement time: 60 minutes Sample concentration: Adjusted to 2% with eluent.

<Production Example 1: Production of PAG dithiol compound 1>
(1. Tosylation step)
In a glass reactor equipped with a stirrer, 11.18 parts of polyethylene glycol (PEG25) having an average addition mole number of ethylene oxide of 25, 4.576 parts of tosyl chloride (TsCl), and triethylamine (Et ₃ N) were added. 3.036 parts and 100.0 parts of dichloromethane (CH ₂ Cl ₂ ) were charged. After reacting for 24 hours while stirring the reaction system, the salt was removed by filtration, and the filtrate was desolvated under reduced pressure to obtain tosylated PEG25 at both ends (PEG25-2OTs).

(2. Thioacetylation process)
In a glass reactor equipped with a stirrer, 14.27 parts of PEG25-2OTs, 2.741 parts of potassium thioacetate (CH ₃ COSK), and 100.0 parts of acetonitrile (CH ₃ CN) were charged. After reacting for 24 hours while stirring the reaction system, the salt was removed by filtration, and the solvent was removed under reduced pressure to obtain a thioacetylated compound at both ends of PEG25 (PEG25-2SAc).

(3. Hydrolysis step)
In a glass reactor equipped with a stirrer, 12.34 parts of synthesized PEG25-2SAc and 50.00 parts of methanol (MeOH) were charged to dissolve PEG25-2SAc, and 1N aqueous sodium hydroxide (NaOH) solution was added. After 25.00 parts were added and stirred for 10 minutes, 25.00 parts of 1N hydrochloric acid (HCl) was added and stirred for another 10 minutes, dichloromethane was added to perform extraction, the organic layer was recovered, and the solvent was removed under reduced pressure. To obtain PAG dithiol compound 1. As a result of NMR analysis of the obtained target compound, the average number of introduced SH per PEG25 molecule was 2.0.

<Production Examples 2 and 3: Production of PAG dithiol compounds 2 and 3>
In Production Examples 2 and 3, PAG dithiol compounds 2 and 3 were synthesized according to the same formulation as in Production Example 1. The charged amount of each raw material is as shown in Tables 1-3.

The symbols in Tables 1 to 3 are summarized below. PEG25, PEG50, and PEG100 are respectively polyethylene glycol having an average addition mole number of ethylene oxide of 25, 50, and 100, PEG25-2OTs, PEG50-2OTs, and PEG100-2OTs are respectively MPEG25, 50 and 100 ditosylated products, PEG25-2SAc, PEG50-2SAc and PEG100-2SAc are dithioacetylated products of PEG25, 50 and 100, respectively.
The same applies to the following tables.

<Comparative Production Examples 1 and 2: Production of PAG Dithiol Compounds 4 and 5>
(1. Dehydration esterification process)
Dean Stark apparatus with Jimroth condenser, Teflon (registered trademark) stirrer blade and stirrer with stir seal, glass reactor equipped with temperature sensor with glass protective tube, average added mole number of ethylene oxide 25 Polyethylene glycol (PEG25) of 100.00 parts, 3-mercaptoisobutyric acid (MiBA) 23.64 parts, p-toluenesulfonic acid monohydrate (PTS · 1H ₂ O) 2.473 parts, phenothiazine ( 0.6182 parts of PTZ) and 6.182 parts of cyclohexane (CyH) were charged. After the Dean-Stark apparatus was filled with cyclohexane, the reaction system was heated to reflux while stirring. The temperature of the heating oil bath was 120 ± 5 ° C. Cyclohexane was added on the way so that the temperature in the reaction system became 110 ± 5 ° C., and the reaction was carried out by heating under reflux while distilling off water for 65.0 hours.

(2. Desolvation step)
After completion of the reaction, the mixture was allowed to cool to 60 ° C. with stirring so as not to solidify, and then an aqueous solution obtained by adding 288.50 parts of ion-exchanged water (PW) to 1.647 parts of 30% NaOH aqueous solution was quickly put into the reactor. I put it in. Subsequently, the temperature was gradually raised to about 100 ° C., and cyclohexane was distilled off. Heating was stopped, nitrogen was bubbled at 30 mL / min for 90 minutes while cooling, and the remaining cyclohexane was removed to obtain an aqueous solution of PAG dithiol compound 4.
As a result of LC analysis of the obtained target compound, the PEG consumption rate was 92.0%, and the average number of SH introduced per molecule of PEG25 was 1.84.
Comparative Production Example 2 was synthesized with the same formulation as Comparative Production Example 1. The amount of each raw material charged is as shown in Table 4.

<Production Examples 4 to 11: Production of copolymers 1 to 8>
(4. Block weight process)
A glass reactor equipped with a thermometer, a stirrer, a dripping device, a nitrogen introducer, and a reflux cooling device was charged with 15.0 parts of ion-exchanged water, and the reactor was purged with nitrogen under stirring. Then, an aqueous solution (A) (acid aqueous solution) composed of 2.160 parts of methacrylic acid (MAA) and 8.640 parts of ion-exchanged water (PW) was dropped into the solution over 4.0 hours, and (A) At the same time, an aqueous solution (B) (PAG thiol aqueous solution) composed of 2.840 parts of PAG dithiol compound 1 and 6.627 parts of ion-exchanged water is dropped over 4.0 hours, and (A) starts to be dropped. At the same time, the azo initiator 2,2′-azobis-2-methylpropionamidine hydrochloride [2,2′-azobis (2-methylpropionamidine) dihydrochloride] (Wako Chemical Industries Co., Ltd. V-50) 0.1360 parts of an aqueous solution comprising an ion-exchanged water 9.733 parts (C) 5.0 hour period was added dropwise. Thereafter, after maintaining the temperature at 80 ° C. for 1 hour, the mixture was cooled to complete the polymerization, and the copolymer 1 of the present invention (an aqueous solution containing a copolymer for cement admixture which is a preferred embodiment) was prepared. Obtained. When the reaction rate (consumption rate) was determined by GPC, LC, and CE, the reaction rate of PAG dithiol compound 1 (shown in the column of thiol of consumption rate (%) in the table) was 95.00%, of methacrylic acid The reaction rate (shown in the column of acid of consumption rate (%) in the table) was 95.00%.

In Production Examples 5 to 11, copolymers 2 to 8 were synthesized in the same manner as in Production Example 4. The amount of each raw material charged is as shown in Table 5.

In the table, MAA / SH indicates the degree of polymerization of MAA bonded to the thiol end. That is, the value of (number of unsaturated carboxylic acid monomers) / (number of SH) is (m ₁ + m ₂ ) / 2 in the above formula, and unsaturated carboxylic acid monomers per SH. The average number of polymerizations.
Moreover, the amount of the PAG thiol compound in the PAG thiol aqueous solution was described in the column of thiol in the PAG thiol aqueous solution, and the amount of methacrylic acid in the acid aqueous solution was described in the acid column of the acid aqueous solution.

<Comparative Production Examples 3-7: Production of Copolymers 9-13>
A glass reactor equipped with a thermometer, a stirrer, a dripping device, a nitrogen introducer, and a reflux cooling device was charged with 15.0 parts of ion-exchanged water, and the reactor was purged with nitrogen under stirring. Then, an aqueous solution (A) composed of 2.160 parts of methacrylic acid (MAA) and 8.640 parts of ion-exchanged water (PW) is dropped over 4.0 hours, and (A) starts to be dropped. At the same time, 9.467 parts of PAG dithiol compound 4 aqueous solution (B) (PAG thiol aqueous solution) are added dropwise over 4.0 hours, and (A) starts to be added at the same time as the azo initiator 2,2′-azobis-2-methyl. Propionamidine hydrochloride [2,2′-azobis (2-methylpropionamidine) dihydrochloride] (V-50, manufactured by Wako Pure Chemical Industries, Ltd.) 0.1360 parts and Io Aqueous solution consisting exchanged water 9.733 parts (C) over a period of 5.0 hours was added dropwise. Thereafter, the temperature was maintained at 80 ° C. for 1 hour, followed by cooling to complete the polymerization, and a comparative copolymer 9 (an aqueous solution containing a cement admixture copolymer) was obtained. When the reaction rate was determined by GPC, LC, and CE, the reaction rate of PAG dithiol compound 4 was 95.00%, and the reaction rate of methacrylic acid was 95.00%.

In Comparative Production Examples 4 to 7, copolymers 9 to 12 were synthesized with the same formulation as Comparative Production Example 3. The amount of each raw material charged is as shown in Table 6.

In the table, MAA / SH indicates the degree of polymerization of MAA bonded to the thiol end.
Moreover, the amount of the PAG thiol compound in the PAG thiol aqueous solution was described in the column of thiol in the PAG thiol aqueous solution, and the amount of methacrylic acid in the acid aqueous solution was described in the acid column of the acid aqueous solution.

<Examples 1-3, Comparative Examples 1-3>
A mortar test was carried out using the copolymers 1, 6, 7, 9, 11, and 12.

<Mortar test method>
A kneader for mechanical kneading, a spoon, a flow table, a flow cone, and a stick according to JIS-R5201-1997 were used. At this time, unless otherwise specified, a mortar test was performed in accordance with JIS-R5201-1997.
The material and mortar used in the test consisted of 587 g of ordinary portland cement manufactured by Taiheiyo Cement Co., 1350 g of standard sand for cement strength test in accordance with JIS-R5201-1997, an aqueous copolymer solution and an antifoaming agent for cement admixture. 264.1 g of ion-exchanged water containing The solid content [nonvolatile component] in the aqueous copolymer solution is measured by removing a volatile component by heating and drying an appropriate amount of the aqueous copolymer solution at 130 ° C., and a predetermined amount of solid content [ The aqueous copolymer solution was weighed and used so that the non-volatile component was included. The antifoaming agent was added for the purpose of avoiding the influence of air bubbles on the dispersibility of the mortar composition so that the air amount was 3.0% or less. Specifically, the oxyalkylene-based antifoaming agent was used in an amount so as to be 0.1% with respect to the cement admixture copolymer. When the amount of air in the mortar is larger than 3.0%, the amount of the antifoaming agent is adjusted so that the amount of air becomes 3.0% or less.
The mortar was prepared at room temperature (20 ± 2 ° C.) using a Hobart mortar mixer (model number N-50, manufactured by Hobart) for 4 minutes and 30 seconds. Specifically, a prescribed amount of cement is put in a kneading bowl, attached to a kneader and started at a low speed. 15 seconds after starting the paddle, a predetermined amount of water containing a copolymer for cement admixture and an antifoaming agent is added for 15 seconds. Then, sand is added and mixed at a low speed for 30 seconds, then at a high speed and continuously mixed for 30 seconds. Remove the kneader from the kneader and stop kneading for 120 seconds, then attach the kneader again to the kneader and knead for 60 seconds at high speed (4 minutes 30 minutes after starting at the first low speed) After 10 seconds, stir 10 times each with a spoon. The kneaded mortar is divided into two layers and packed in a flow cone placed on a flow table. Each layer is struck 15 times over the entire surface so that the tip of the stab stick is about half the depth of the layer, and finally, the shortage is compensated, the surface is smoothed, and the start is started at a low speed first. 6 minutes later, after the flow cone was lifted vertically, the diameter of the mortar spread on the table was measured in two directions, and this average value was taken as the flow value.

Table 7 shows MAA number / SH value (average value of the number of MAAs subjected to addition polymerization to one thiol group (SH)) in the test samples (Copolymers 1, 6, 7, 9, 11, 12). The ratio of the addition amount of the test sample to the copolymer 1 (the addition amount of each copolymer in the mortar test calculated based on the addition amount of the copolymer (1) in the mortar test as 1.000) showed that.
FIG. 1 shows a graph in which the horizontal axis represents MAA / SH, and the vertical axis represents the addition amount ratio with the copolymer 1. The lower the value on the vertical axis, the higher the cement fluidity. As a result, it was found that at least the chain length (average added mole number of ethylene oxide) of 25 and 75 is more than 0 and 40 / SH or less, the non-ester type has higher fluidity than the ester type. .

<Examples 4-8, Comparative Examples 4-8>
Hydrolysis tests were performed using Copolymers 1, 2, 6-13.

<Hydrolysis test method>
The copolymer was dissolved in an aqueous NaOH solution to prepare a 2% aqueous solution. At that time, the pH of the NaOH aqueous solution is adjusted in advance so that the pH of the aqueous solution becomes 12.5. The 2% aqueous solution was stirred for 15 minutes, and then neutralized with a 35% HCl aqueous solution to adjust the pH to 5.0. The hydrolysis rate was calculated from the charts before and after the reaction by GPC.

Table 8 shows the hydrolysis rate of the test sample.
FIG. 2 is a GPC chart.
In the ester type, the molecular weight of the polymer decreases and the peak of the raw material PEG increases after the test. This shows that the hydrolysis is proceeding. However, it was found that in the non-ester type, there was no change in the chart before and after the test, and hydrolysis did not proceed substantially.
The decomposition rate calculation method is as follows.
“Polymer Area before Decomposition” and “Polymer Area after Decomposition” are the integrated values of the molecular weight distribution curves of the GPC chart before hydrolysis (before the test) and after hydrolysis (after the test) (the X axis of the GPC chart and The area of the region according to the molecular weight distribution curve).

Claims (7)

A structure in which a polymer chain (A) based on an unsaturated carboxylic acid monomer unit and a polymer chain (B) based on a (poly) alkylene glycol structural unit are bonded via a binding site (X) is essential. A (poly) alkylene glycol block copolymer,
The (poly) alkylene glycol block copolymer is
The polymer chain (A) and the polymer chain (B) are bonded via the binding site (X) in the order of the polymer chain (A), the polymer chain (B), and the polymer chain (A). Has a structure,
The (poly) alkylene glycol block copolymer, wherein the binding site (X) does not form an ester bond with the terminal oxygen atom of the polymer chain (B) and contains a sulfur atom. The (poly) alkylene glycol block copolymer is
The following general formula (1):

(In the formula, X ₁ and X ₂ are the same or different and represent an organic residue. AO is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. R ¹ is the same or different. A hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms, wherein R ² , R ³ , R ⁴ , and R ⁵ are each a single unit. In the monomer unit, at least one is —COOM ¹ and the remaining R ² , R ³ , R ⁴ , and R ⁵ are the same or different and are a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or — ( ^{_{CH 2) zCOOM 2 (- (}} CH 2) zCOOM 2 is, COOM ¹ or other _- (CH ²⁾ _zCOOM 2 and anhydride may form a) represents, z are the same or different, 0 Represents an integer of 2. n represents oxyalkylene. Represents the average number of moles added, .m ₁ and _{m 2} is a number of 1 to 500 are the same or different, .M ¹ and ^{M 2} is the number of 1 to 500 are the same or different, a hydrogen atom, one A valent metal, a divalent metal, a trivalent metal, a quaternary ammonium group, or an organic amine group, wherein m ₁ monomer unit bonded via AO and —O—X—, and AO And m ₂ monomer units bonded through -X- may be the same or different.), According to claim 1, Poly) alkylene glycol block copolymer. The (poly) alkylene glycol block copolymer according to claim 1 or 2, wherein the (poly) alkylene glycol block copolymer has a sulfur atom content of 0.15% by mass or more based on the total copolymer. Glycol block copolymer. The (poly) alkylene glycol block copolymer has a 10% by mass decomposition rate of the copolymer into a polymer chain (A) and a polymer chain (B) after 15 minutes in a 2% by mass alkaline aqueous solution of the copolymer. The (poly) alkylene glycol block copolymer according to claim 1, wherein: A dispersant comprising the (poly) alkylene glycol block copolymer according to claim 1. A cement admixture comprising the (poly) alkylene glycol block copolymer according to any one of claims 1 to 4. A cement composition comprising the cement admixture according to claim 6, cement and water.

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