JP5992790B2 - Polyalkylene glycol block copolymer for cement admixture, polyalkylene glycol block copolymer, dispersant, cement admixture, and cement composition - Google Patents

Description

The present invention relates to a polyalkylene glycol block copolymer and a polyalkylene glycol block copolymer for cement admixture. More specifically, the present invention relates to a polyalkylene glycol block copolymer for cement admixture suitably used for cement admixture, and a polyalkylene glycol block copolymer suitably used for dispersant, cement admixture and the like.

A polymer containing a polyalkylene glycol chain (hereinafter, also referred to as a polyalkylene glycol polymer) has properties such as hydrophilicity, hydrophobicity, and steric repulsion by appropriately adjusting the chain length and the constituent alkylene oxide. Cement admixture applications that are applied and added to cement compositions such as cement paste, mortar, concrete, etc. are being studied. 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 naphthalene was conventionally used, but the polyalkylene glycol chain can act as a dispersing group to disperse cement particles due to its steric repulsion, and therefore contains a polyalkylene glycol chain. The polycarboxylic acid-based water reducing agent has been newly 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 polyalkylene glycol chain, for example, a copolymer obtained by block polymerization of methacrylic acid at both ends / one end of a polyalkylene glycol chain (for example, see Patent Document 1) is disclosed.
Also disclosed is a copolymer produced by atom transfer radical polymerization (ATRP polymerization) in the form of a copolymer of a poly (alkylene oxide) compound and an ethylenically unsaturated monomer compound (see, for example, Patent Document 2). ing.
In addition, as a biodegradable water-soluble polymer used in detergent builders, a monoethylenically unsaturated monomer component is blocked or grafted to a modified polyether compound in which a compound having a mercapto group is introduced into a polyether compound by an ester reaction. A polymer obtained by polymerization is disclosed (for example, see Patent Document 3). Furthermore, it is disclosed that a novel polymer having a polymer unit comprising a polyalkylene glycol chain and a constituent unit derived from an unsaturated monomer bonded to at least one end of the chain is particularly useful as a cement admixture. (For example, refer to Patent Document 4).

US Pat. No. 6,248,839 US Pat. No. 7,425,596 JP-A-7-109487 JP 2007-119736 A

As described above, polymers having various structures have been disclosed as polyalkylene glycol chain-containing polymers. However, the extremely high performance (cement dispersibility (water-reducing), slump flow) required recently is still sufficient. It has not reached the level where it can be demonstrated. 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 need for a cement admixture that has a simple molecular structure and manufacturing method and exhibits excellent characteristics.

The present invention has been made in view of the above situation, and provides a copolymer having a simple molecular structure capable of exhibiting performance such as water reduction and workability in a cement composition at a high level. For the purpose.

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 polyalkylene glycol block copolymer for cement admixture, which has a structure in which a polymer chain (B) with a polyalkylene glycol structural unit is bonded via a bonding site (X), the polymer The 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 in this order via the binding site (X). The copolymer having a structure in which the average addition mole number of the oxyalkylene group of the polyalkylene glycol structural unit in the polymer chain (B) is 25 or more is cement dispersibility ( Decrease Excellent properties of sex) and slump flow, etc. were found to be a polymer which can be suitably used as a cement admixture.
Furthermore, the present inventors bonded the polymer chain (A) based on the unsaturated carboxylic acid monomer unit and the polymer chain (B) based on the polyalkylene glycol structural unit via the binding site (X). A polyalkylene glycol block copolymer having an essential structure, wherein the polymer chain (A) and the polymer chain (B) are polymer chains (A), polymer chains (B), It has a structure in which the molecular chain (A) is bonded through the bonding site (X) in this order, and the average addition mole number of the oxyalkylene group of the polyalkylene glycol-based structural unit in the polymer chain (B) is 70 or more. The copolymer having the structure is excellent in properties such as cement dispersibility (water reduction) and slump flow despite its simple structure, and can be suitably used as a cement admixture. Dispersion Found that can be suitably used as a.

That is, the polyalkylene glycol block copolymer for cement admixture of the present invention comprises a polymer chain (A) composed of unsaturated carboxylic acid monomer units and a polymer chain (B) composed of polyalkylene glycol structural units. Is a polyalkylene glycol-based block copolymer for cement admixture, which essentially has a structure bonded through a bonding site (X),
The above polyalkylene glycol block copolymer for cement admixture 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 average addition mole number of the oxyalkylene group of the polyalkylene glycol structural unit in the polymer chain (B) is 25 or more.
In the polyalkylene glycol block copolymer of the present invention, the polymer chain (A) comprising an unsaturated carboxylic acid monomer unit and the polymer chain (B) comprising a polyalkylene glycol constituent unit are bonded to each other. A polyalkylene glycol block copolymer essentially comprising a structure bonded via (X),
The polyalkylene 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 average addition mole number of the oxyalkylene group of the polyalkylene glycol structural unit in the polymer chain (B) is 70 or more.
Hereinafter, in the present specification, when simply referred to as “the present invention” or “the copolymer of the present invention”, the polyalkylene glycol block copolymer for cement admixture of the present invention and the polyalkylene glycol block of the present invention are used. It shall mean the matters common to the copolymer.
In addition, regarding technical features common to the polyalkylene glycol block copolymer for cement admixture of the present invention and the polyalkylene glycol block copolymer of the present invention, refer to the polyalkylene glycol block copolymer for cement admixture of the present invention. It will be explained in the description of coalescence. In the description of the polyalkylene glycol block copolymer of the present invention, technical features different from the polyalkylene glycol block copolymer for cement admixture of the present invention will be described.
A combination of two or more preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

<Polyalkylene glycol block copolymer for cement admixture>
The polyalkylene glycol block copolymer for cement admixture of the present invention has a polymer chain (A) composed of unsaturated carboxylic acid monomer units and a polymer chain (B) composed of polyalkylene glycol structural units. A polyalkylene glycol-based block copolymer for cement admixtures that requires a structure bonded through a bonding site (X),
The above polyalkylene glycol block copolymer for cement admixture 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 average addition mole number of the oxyalkylene group of the polyalkylene glycol structural unit in the polymer chain (B) is 25 or more.

As an example of the polyalkylene glycol block copolymer for cement admixture of the present invention, a copolymer having the structure of the following general formula (1) may be mentioned.

（式中、Ｘ_１及びＸ_２は、同一又は異なって、有機残基を表す。ＡＯは、同一又は異なって、炭素数２〜１８のオキシアルキレン基を表す。Ｒ^１は、夫々同一又は異なって、水素原子、炭素数１〜１０のアルキル基又は炭素数１〜１０のアルケニル基を表す。Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５は、少なくとも一つが−ＣＯＯＭ^１であり、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５は、同一又は異なって、水素原子、炭素数１〜１０のアルキル基、−（ＣＨ_２）ｚＣＯＯＭ^２（−（ＣＨ_２）ｚＣＯＯＭ^２は、ＣＯＯＭ^１またはその他の−（ＣＨ_２）ｚＣＯＯＭ^２と無水物を形成していてもよい）を表し、ｚは０〜２の整数を表す。ｎは、オキシアルキレン基の平均付加モル数を表し、２５以上の数である。ｍ_１及びｍ_２は、不飽和カルボン酸系単量体単位の平均導入モル数を表す。）

(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. Each represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 1 to 10 carbon atoms, wherein at least one of R ² , R ³ , R ⁴ , and R ⁵ is —COOM ¹ , 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, — (CH ₂ ) zCOOM ² (— (CH ₂ ) zCOOM ² is COOM ¹ or other — (CH ₂ ) zCOOM ² and an anhydride may be formed), and z represents an integer of 0 to 2. n represents the average number of moles added of the oxyalkylene group and is a number of 25 or more. M ₁ and m ₂ are unsaturated carboxylic acid based monomers Represents the average number of moles of body units introduced.)

-O- (AO) n- shown at the center in the general formula (1) is an oxygen atom at the terminal of the polyoxyalkylene group constituting the polymer chain (B) of the polyalkylene glycol structural unit and polyoxy An alkylene group; n represents the average number of added moles of the oxyalkylene group of the polyalkylene glycol structural unit.
X ₁ and X ₂ located on both sides of the polyoxyalkylene group are bonding sites, and the polymer chain (A) by the unsaturated carboxylic acid monomer unit is formed through the polyalkylene glycol structure via X ₁ and X _2. Bonded to both ends of the polymer chain (B) by the unit.
m ₁ and m ₂ represent the average number of moles of unsaturated carboxylic acid monomer units introduced, respectively.
Hereinafter, the polymer chain (A) based on the unsaturated carboxylic acid monomer unit, the polymer chain (B) based on the polyalkylene glycol structural unit, and the binding site (X) will be described.

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

(In the formula, at least one of R ² , R ³ , R ⁴ , and R ⁵ is —COOM ¹ , and R ² , R ³ , R ⁴ , and R ⁵ are the same or different and have a hydrogen atom, carbon number 1 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) represent, 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. Are preferred.
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 and fumaric acid. Examples thereof include dicarboxylic acid monomers, 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 copolymer of 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 20 or more in the entire copolymer. It is preferable that
Hereinafter, the value of the average number of moles of unsaturated carboxylic acid monomer units introduced is the average of unsaturated carboxylic acid monomer units in the entire copolymer contained in 1 mole of the copolymer of the present invention. This means the number of moles introduced.
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. That the total is 20 or more means that the value of m ₁ + m ₂ is 20 or more.
The lower limit of the average number of moles introduced is more preferably 25, and even more preferably 30. The upper limit is preferably 500, more preferably 300, and even more preferably 100.
By setting the average number of introduced moles to 20 or more, the copolymer can sufficiently exhibit the performance based on the polymer chain (A) based on the unsaturated carboxylic acid monomer unit.
In addition, when the average number of moles introduced exceeds 500, the amount of unsaturated carboxylic acid monomer introduced into the entire copolymer increases, and as a result, the number of polyalkylene glycol structural units that disperse the cement decreases. Therefore, the cement dispersion performance is deteriorated. It is necessary to appropriately set the ratio of the unsaturated carboxylic acid monomer unit to the polyalkylene glycol constituent unit.

R ¹ in the general formula (1) represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 1 to 10 carbon atoms.
R ¹ is a site corresponding to the polymerization termination terminal of the polymer chain (A) by the unsaturated carboxylic acid monomer unit.

<Polymer chain (B) by polyalkylene glycol structural unit>
The polymer chain (B) based on a polyalkylene glycol (hereinafter, polyalkylene glycol is also referred to as PAG) -based structural unit is a polymer chain composed of polyalkylene oxide.
The polymer chain (B) is preferably a polymer chain (polyalkylene oxide) composed of an alkylene oxide having 2 to 18 carbon atoms.
More preferably, it 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, tetramethylethylene oxide, butadiene. Examples include 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 polyalkylene glycol-based structural unit is preferably appropriately selected according to the use required for the polyalkylene glycol-based block copolymer of the present invention. For example, in the production of a cement admixture component Therefore, from the viewpoint of affinity with cement particles, it is preferable that the main component is a relatively short chain alkylene oxide (oxyalkylene group) having about 2 to 8 carbon atoms. 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 “main body” as used herein means that the majority of the total number of alkylene oxides occupies when the polymer chain (B) of the polyalkylene glycol structural unit is composed of two or more types of alkylene oxides. 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 polyalkylene 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) of the above polyalkylene glycol-based structural unit is composed of two or more kinds of alkylene oxides, two or more kinds of alkylene oxides are added in any form such as random addition, block addition, and alternate addition. It may be what you did.

When the polymer chain (B) by the polyalkylene glycol-based structural unit also contains an alkylene oxide having 3 or more carbon atoms, it becomes possible to impart a certain degree of hydrophobicity to the copolymer of the present invention. Therefore, when the above copolymer is used as a cement admixture, a slight structure (network) is provided to the cement particles, and the viscosity and stiffness of the cement composition can be reduced. 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, the polymer chain (B) composed of the polyalkylene glycol structural unit and the polymer chain (A) composed of the unsaturated carboxylic acid monomer unit may be cleaved by hydrolysis depending on the structure of the binding site. is there. When improvement in hydrolysis resistance is required, it is preferable to introduce an oxyalkylene group having 3 or more carbon atoms at the terminal of the polymer chain (B) by the polyalkylene 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.
The introduction amount of the oxyalkylene group having 3 or more carbon atoms depends on the required hydrolysis resistance, but the introduction amount is 50 with respect to both ends of the polymer chain (B) by the polyalkylene glycol-based structural unit. It is preferably at least mol%. 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 polyalkylene glycol block copolymer for cement admixture of the present invention, the average number of repeating alkylene oxides in the polymer chain (B) by the polyalkylene glycol structural unit (average added mole number of oxyalkylene groups) is , 25 or more.
In the general formula (1), the average number of repeating alkylene oxides is represented by n.
By setting n to a number of 25 or more, the polyalkylene glycol block copolymer for cement admixture of the present invention can sufficiently exhibit the performance based on the polymer chain (B) by the polyalkylene glycol structural unit. It becomes possible.

In the polyalkylene glycol block copolymer for cement admixture of the present invention, the upper limit of the average added mole number of oxyalkylene groups is not particularly limited, but is preferably 1000, more preferably 800. More preferably, it is 500, More preferably, it is 300, More preferably, it is 200, More preferably, it is 150. The lower limit is preferably 50, more preferably 75, still more preferably 100, and still more preferably 120.
When the average number of repetitions exceeds 1000, the viscosity of the raw material compound used to produce the copolymer is increased, or the reactivity is not sufficient, and is preferable in terms of workability. There is a risk of not being able to.
The average number of repeating alkylene oxides (average number of moles of oxyalkylene group added) refers to the number of additions in 1 mole of the polymer chain (B) by the polyalkylene glycol structural unit of the copolymer of the present invention. Means the average number of moles of alkylene oxide.

<Binding site (X)>
As the bonding site (X) in the copolymer of the present invention, a polymer chain (A) composed of an unsaturated carboxylic acid monomer unit and a polymer chain (B) composed of a polyalkylene glycol structural unit are chemically synthesized. The structure is not particularly limited as long as it has a structure that can be stably bonded.
As a preferable structure of the binding site, an organic residue derived from a structure serving as a chain transfer agent used in a polymerization reaction can be given.
In the general formula (1), organic residues as binding sites are indicated by X ₁ and X ₂ .
Examples of binding site (X) include (i) a binding site containing a sulfur atom, (ii) a binding site derived from an azo initiator, (iii) a binding site derived from a residue containing a phosphorus atom, (iv) other Examples include structure-derived binding sites.
The structures of the organic residues present at a plurality of binding sites may be the same or different.

(I) Binding site containing a sulfur atom Examples of the binding site containing a sulfur atom include the following formula (3):

[Wherein R ⁶ is an organic residue, preferably an aromatic group 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. Group or mercaptocarboxylic acid residue (which 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.)] The structure shown by is mentioned.
Among the bonding sites containing the sulfur atom, in particular, the following formula (4):

[Wherein R ⁷ is a mercaptocarboxylic acid residue, preferably a linear or branched alkylene group having 1 to 18 carbon atoms, phenyl group, alkylphenyl group, pyridinyl group, thiophene, pyrrole, furan, thiazole, etc. In which the structure is partially substituted by a hydroxyl group, amino group, cyano group, carbonyl group, carboxyl group, halogen group, sulfonyl group, nitro group, formyl group, etc.] preferable.

R ⁶ of the structure represented by the above formula (3) is a site bonded to the polymer chain (B) by the polyalkylene glycol-based structural unit, and the sulfur atom (S) is high by the unsaturated carboxylic acid-based monomer unit. This is the site that binds to the molecular chain (A).
The structure of one end of the binding site represented by the above formula (4) (the bond on the left side of the formula (4)) is a hydroxyl group at the terminal of the polymer chain (B) by the carboxyl group of mercaptocarboxylic acid and the polyalkylene glycol-based structural unit. It is obtained by inducing a dehydration esterification reaction with a group.
Using the thiol ester obtained by the esterification reaction as a chain transfer agent, the unsaturated monocarboxylic acid monomer (a) can be block polymerized using a radical polymerization initiator, and as a result, the above formula (4) It becomes a binding site of the structure shown in FIG.
Examples of mercaptocarboxylic acids include mercaptoacetic acid, mercaptopropionic acid, 3-mercaptoisobutyric acid, 11-mercaptoundecanoic acid and the like. Among these, 3-mercaptoisobutyric acid and 3-mercaptopropionic acid are preferable.

(Ii) Binding site derived from an azo initiator The binding site derived from an azo initiator is a site derived from a polymerization initiator (azo initiator) containing an azo group, for example, as shown in the following formula (5) Examples include structures derived from azo initiators.

[Wherein, R ⁸ are independently of each other an alkylene group having 1 to 20 carbon atoms (the alkylene group is partially substituted with an alkyl group, an alkenyl group, a hydroxyl group, a cyano group, a carboxyl group, an amino group, etc. ), A carbonyl group or a carboxyl group, or an alkylene group having 1 to 20 carbon atoms (the alkylene group is an alkyl group, an alkenyl group, a hydroxyl group, a cyano group, a carboxyl group, an amino group, etc.). Is a group bonded to a carbonyl group or a carboxyl group, and R ⁹ is independently of each other an alkyl group having 1 to 20 carbon atoms, carboxy-substituted (having 1 to 10 carbon atoms). an alkyl group, a phenyl group or substituted phenyl group, R ¹⁰ is, independently of one another, a cyano group, an acetoxy group, a carbamoyl group or a (carbon number 1 to 1 Is alkoxy) carbonyl group. An azo initiator having a repeating unit represented by
More preferably, the azo initiator shown by following formula (6) is mentioned.

The azo initiator represented by the above formula (6) preferably has a structure in which the terminal is previously bonded to the polymer chain (B) by a polyalkylene glycol structural unit by an ester bond.
Specific examples thereof include polymer azo initiator VPE series commercially available from Wako Pure Chemical Industries, Ltd., for example, VPE-0401 (number average molecular weight of about 2.5 to 40,000, molecular weight of polyethylene oxide portion of about 4, 000, average addition mole number of oxyethylene group n = 90), VPE-0601 (number average molecular weight about 2.5 to 40,000, molecular weight of polyethylene oxide part about 6,000, average addition mole number of oxyethylene group n = 135).

The structure of the organic residue X as a binding site derived from the azo initiator represented by the above formulas (5) and (6) is a structure represented by the following formulas (7) and (8).

^Wherein, R ^8, R ^{9, R 10} are the same as ^{R 8,} R ^{9, R 10} in the formula (5)]

式（８）におけるカルボニル基の炭素がポリアルキレングリコール系構成単位による高分子鎖（Ｂ）と結合する側である。

The carbon of the carbonyl group in Formula (8) is the side bonded to the polymer chain (B) by the polyalkylene glycol structural unit.

(Iii) Binding site derived from a residue containing a phosphorus atom Examples of the binding site containing a phosphorus atom include the following formula (9):

[Wherein Y represents an organic residue. M ³ represents a metal atom, an ammonium group, or an organic amine group].
Y is a site bonded to the polymer chain (B) by the polyalkylene glycol structural unit, and the phosphorus atom of hypophosphorous acid (salt) bonded to Y is a polymer by the unsaturated carboxylic acid monomer unit. This is the site that binds to the chain (A).

Examples of the organic residue include a linear, branched or cyclic alkylene group having 2 to 30 carbon atoms, and a divalent aromatic group having 6 to 30 carbon atoms (phenylene group, alkylphenylene group, and pyridine, Thiophene, pyrrole, furan, divalent group derived from thiazole, etc.), for example, hydroxyl group, amino group, acetylamino group, cyano group, carbonyl group, carboxyl group, halogen group, sulfonyl group, nitro group, formyl A group which may be partially substituted with a substituent such as a group is preferred.
Among these, more preferably, a divalent organic residue having 2 to 18 carbon atoms and a part thereof are substituted with a hydroxyl group, and more preferably a linear or branched chain having 2 to 8 carbon atoms. -Like alkylene groups and some of them are substituted with hydroxyl groups.

The hypophosphite is preferably a salt formed by hypophosphorous acid and any one of a metal, ammonia or an organic amine. As the metal, an alkali metal, an alkaline earth metal or the like is preferable. Examples of organic amines include alkylamines having 1 to 18 carbon atoms, hydroxyalkylamines, polyalkylenepolyamines and the like. Among these, a salt formed by sodium, potassium, ammonia, or triethanolamine is preferable.

(Iv) Binding sites derived from other structures Specific examples of the binding sites derived from other structures include the following binding sites derived from chain transfer agents. Among these, those having a sulfur atom are also included in the above (i) binding site containing a sulfur atom.
For example, after reacting a thiocarboxylic acid such as thioacetic acid and thiobenzoic acid with zinc halide on the terminal -OH group of polyalkylene glycol, alkali hydrolysis is performed to convert the -OH group to -SH. Compound converted into a group; after reacting diethyl azodicarboxylate (DEAD) with triphenylphosphine in the presence of polyalkylene glycol and thioacetic acid, alkali hydrolysis is performed to form a terminal -alkylene glycol- Compound in which OH group is converted to —SH group; Compound in which allyl halide such as allyl bromide is SN2 reacted with —OH group at the terminal of polyalkylene glycol to allylate the terminal of polyalkylene glycol; To compounds with double bonds such as allyl groups at the end, thioacetic acid, thiobenzoate After addition of thiocarboxylic acid such as an acid, by performing alkaline hydrolysis, the compound was converted to -SH group;
These compounds (chain transfer agents) may be used alone or in combination of two or more.

<Polyalkylene glycol block copolymer for cement admixture>
A structure in which a polymer chain (A) based on an unsaturated carboxylic acid monomer unit and a polymer chain (B) based on a polyalkylene glycol structural unit are bonded via a binding site (X) is essential. Among the polyalkylene glycol block copolymers for cement admixture according to the invention, a particularly preferred structure is a structure represented by the following formula (10) or (11).

[Wherein, R ² are the same or different and each represents a hydrogen atom or a methyl group. n represents an average addition mole number of the oxyalkylene group and is a number of 25 or more. m ₁ and m ₂ each represent the average number of moles of unsaturated carboxylic acid monomer units introduced. ]

In the above structure, the unsaturated monocarboxylic acid monomer in the general formula (1) is acrylic acid or methacrylic acid, the polymer chain based on the polyalkylene glycol structural unit is a polyethylene glycol chain, and the bonding site (X) is 3 -A structure that is a binding site containing a sulfur atom derived from mercaptoisobutyric acid.

[Wherein, R ² are the same or different and each represents a hydrogen atom or a methyl group. n represents an average addition mole number of the oxyalkylene group and is a number of 25 or more. m ₁ and m ₂ each represent the average number of moles of unsaturated carboxylic acid monomer units introduced. ]

In the above structure, the unsaturated monocarboxylic acid monomer in the general formula (1) is acrylic acid or methacrylic acid, the polymer chain based on the polyalkylene glycol structural unit is a polyethylene glycol chain, and the bonding site (X) is 3 -A structure which is a binding site containing a sulfur atom derived from mercaptopropionic acid.
In the above formulas (10) and (11), the positions of R ² and the COOH group of the unsaturated carboxylic acid monomer unit are drawn on the terminal hydrogen atom side. The position of ² and the COOH group may be located on the sulfur atom side. In the structures represented by the above formulas (10) and (11), it is randomly determined for each monomer unit whether the position of the R ² and COOH groups is on the hydrogen atom side or on the sulfur atom side.

The polyalkylene glycol block copolymer for cement admixture of the present invention has a weight average molecular weight in consideration of its handleability and the retention of the cement composition when the polymer is used for cement admixture. (Mw) 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 5000 or more, More preferably, it is 10,000 or more, Especially preferably, it is 20,000 or more, Most preferably, it is 30,000 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 2500 or more, More preferably, it is 5000 or more, Especially preferably, it is 10,000 or more, Most preferably, it is 15000 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 copolymer>
As an example of the method for producing a copolymer of the present invention, a case of producing a copolymer having a binding site containing a sulfur atom derived from mercaptocarboxylic acid will be described below.

The copolymer according to the present invention is prepared by preparing a polymer chain (B) with a polyalkylene glycol structural unit having hydroxyl groups at both ends, and reacting a carboxyl group of mercaptocarboxylic acid with the hydroxyl group ends. A step of obtaining a thiol ester by a step of performing an esterification reaction (esterification reaction step), and block-polymerizing an unsaturated monocarboxylic acid monomer using a radical polymerization initiator using the thiol ester as a chain transfer agent It can manufacture by performing (block polymerization process).
Such a method for producing a copolymer is also one aspect of the present invention.

<Esterification reaction process>
In the esterification reaction step, an ester bond is formed by reacting the hydroxyl group end of the polymer chain (B) with the carboxyl group of mercaptocarboxylic acid by the polyalkylene glycol-based structural unit having hydroxyl group ends at both ends. The thiol ester represented by (12) is obtained.
Hereinafter, a thiol ester having the following structure is also referred to as a PAG thiol compound.

[Wherein, AO is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. n represents the average added mole number of the oxyalkylene group. R ⁷ is a mercaptocarboxylic acid residue, preferably an aromatic group such as a linear or branched alkylene group having 1 to 18 carbon atoms, phenyl group, alkylphenyl group, pyridinyl group, thiophene, pyrrole, furan or thiazole. (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.)]

The PAG thiol compound has a weight average molecular weight (Mw) of 500,000 or less in consideration of 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 thiol compound acts as a chain transfer agent for radical polymerization reaction due to having a mercapto group derived from mercaptocarboxylic acid, and is suitable for production of various polymers using radical polymerization reaction. Can be used.

<Block polymerization process>
As described above, the PAG thiol compound has a function as a chain transfer agent, and this compound is used as a chain transfer agent to radically polymerize an unsaturated monocarboxylic acid monomer component. The polyalkylene glycol block copolymer of the invention can be produced simply and efficiently at a low cost.

When producing a polymer using the PAG thiol compound represented by the general formula (12) as a chain transfer agent, an unsaturated monocarboxylic acid monomer component via the sulfur atom (S) of the PAG thiol compound Are successively 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 thiol compound, the amount used may be appropriately set, but is preferably 0.1 mol with respect to 100 mol of the total amount of unsaturated monocarboxylic acid monomer components. More preferably, it is 0.25 mol or more, more preferably 0.5 mol or more, preferably 20 mol or less, more preferably 15 mol or less, and 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 polyalkylene glycol structural unit may hydrogen bond to form a water-insoluble intermediate. The polymerization rate of (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 50 mol%, more preferably 3 to 40 mol%, still more preferably 5 to 30 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 set as appropriate according to the form and amount of the PAG thiol compound and unsaturated monocarboxylic acid monomer component. If the amount is too small relative to the carboxylic acid monomer component, the radical concentration may be too low and the polymerization reaction may be slow. On the other hand, if the amount is too large, the radical concentration is too high and the polymerization reaction is caused by sulfur atoms. The polymerization reaction from the unsaturated monocarboxylic acid monomer component has priority, and the yield of the polyalkylene 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 with respect to 100 mol of the total amount of unsaturated monocarboxylic acid monomer components. .1 mol or more, particularly preferably 0.2 mol or more, more particularly preferably 1 mol or more, most preferably 5 mol or more, preferably 50 mol or less, more preferably 20 mol or less, still more preferably 10 mol Or less, even more preferably 5 mol or less, particularly preferably 2 mol or less, and most preferably 1 mol 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 monocarboxylic 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; the entire amount is divided or continuously charged into the reaction vessel. Method: 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. The radical polymerization initiator and the chain transfer agent may be charged into the reaction vessel from the beginning, or may be dropped into the reaction vessel, or these may be combined depending on the purpose. The system block copolymer is manufactured by a method in which the whole amount of the PAG thiol compound is initially charged into a reaction vessel at an initial stage, and then an unsaturated monocarboxylic acid monomer component is continuously added thereto. Is preferred. 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. When nitrogen substitution is performed after adding the unsaturated monocarboxylic acid monomer component to the solvent, the dissolved oxygen concentration of the system including the unsaturated monocarboxylic 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. For example, when used for cement admixture, there is a possibility that the dispersion performance cannot be sufficiently exhibited. 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 polyalkylene glycol block copolymer, the reaction product obtained by the above polymerization reaction may contain various polymers as by-products and unreacted raw materials, impurities contained in the raw materials, If necessary, it may be subjected to a process of isolating individual polymers, but it is usually used for various purposes without isolating individual polymers from the viewpoint of work efficiency and production cost. May be.

<Method for producing a copolymer having a binding site other than a binding site containing a sulfur atom>
Up to this point, an example in the case of producing a copolymer having a binding site containing a sulfur atom derived from mercaptocarboxylic acid has been described, but a method for producing a copolymer having another structure as the binding site will be described below. To do.

When producing a copolymer having a binding site derived from an azo initiator, the starting material has a structure in which the terminal of the azo initiator is previously bonded to the polymer chain (B) by the polyalkylene glycol-based structural unit by an ester bond. Things can be used.
For example, VPE-0401 commercially available from Wako Pure Chemical Industries, Ltd. (number average molecular weight of about 2.5 to 40,000, molecular weight of polyethylene oxide portion of about 4,000, average added mole number of oxyethylene group n = 90) , VPE-0601 (number average molecular weight of about 2.5 to 40,000, molecular weight of polyethylene oxide moiety of about 6,000, average number of added moles of oxyethylene group n = 135), and the like.
Those having a structure in which the terminal of the azo initiator is previously bonded to the polymer chain (B) of the polyalkylene glycol-based structural unit by an ester bond include, for example, an azo initiator having a carboxyl group at both ends of the azo group (V- 501 etc., manufactured by Wako Pure Chemical Industries, Ltd.) and polyalkylene glycol having hydroxyl groups at both ends can also be obtained by esterification. As a method of esterification, since a azo initiator will decompose | disassemble when a heating process is performed, the manufacturing method which does not include a heating process is required. As such a production method, (1) a method in which an azo initiator is reacted with thionyl chloride to synthesize an acid chloride, and then an alkoxypolyalkylene glycol is reacted to obtain an azo initiator; (2) an azo initiator and A method of obtaining an azo initiator by dehydration condensation of alkoxypolyalkylene glycol with dicyclohexylcarbodiimide (DCC) and optionally 4-dimethylaminopyridine.

When the azo initiator is used, the azo group is decomposed by heat to generate radicals, from which polymerization starts. Therefore, the unsaturated monocarboxylic acid monomer is successively added to both ends of the polyalkylene oxide portion composed of the oxyalkylene group to form the polyalkylene glycol block copolymer according to the present invention.

When producing a copolymer having a bonding site derived from a residue containing a phosphorus atom, an organic residue having a carbon-carbon double bond at the terminal oxygen atom of the polymer chain (B) by the polyalkylene glycol structural unit It is preferable to produce a phosphorus atom-containing polyalkylene glycol compound by adding hypophosphorous acid (salt) to compound A having a bonded structure.

In addition, the said compound A is compoundable by a well-known method.
The compound A may be synthesized by a method in which a compound having an unsaturated group is added to the polymer chain (B) having a polyalkylene glycol structural unit. As the form of addition, known methods such as esterification, etherification and amidation can be used. The unsaturated compound to be added may be any compound that can be added to the alkylene oxide.

In the step of subjecting compound A to hypophosphorous acid (salt) addition reaction, hypophosphorous acid (salt) is added in an amount of 0.01 to 100 mol with respect to 1 mol of unsaturated bond contained in compound A. It is preferable to add and react. From the viewpoint of increasing the reaction rate of Compound A, hypophosphorous acid (salt) is preferably 0.1 mol or more, more preferably 0.2 mol or more, and even more preferably 0 with respect to 1 mol of Compound A. .5 moles or more. From the viewpoint of reducing unreacted hypophosphorous acid (salt), hypophosphorous acid (salt) is preferably 10 mol or less, more preferably 5 mol or less, and still more preferably 1 mol of Compound A. 2 mol or less.

The step of subjecting compound A to addition reaction of hypophosphorous acid (salt) is preferably performed at a temperature of 0 to 200 ° C. More preferably, it is performed at a temperature of 20 to 150 ° C, more preferably 40 to 120 ° C, and still more preferably 50 to 100 ° C.

It is preferable to purify the resulting phosphorus atom-containing polyalkylene glycol compound after the step of subjecting compound A to addition reaction of hypophosphorous acid (salt). The purification step can be performed by drying the solution after the reaction to remove the solvent, then suspending in the purification solvent and performing filtration, and extraction, or both.
The purification solvent may be selected as appropriate, and for example, THF, acetonitrile, chloroform, isopropyl alcohol and the like are preferable.
The extraction solvent may be selected as appropriate, but it is preferably carried out using water, methanol, acetonitrile, dioxane or the like as the highly polar solvent. It is preferable to use diethyl ether, cyclohexane, chloroform, methylene chloride or the like as the low polarity solvent.

The step of subjecting compound A to hypophosphorous acid (salt) to an addition reaction can be performed in a solution state in which a radical polymerization initiator is used as necessary and dissolved in a solvent. Examples of the solvent used in this case include water; alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, cyclohexane, and n-hexane; ethyl acetate and the like. Ester compounds; ketone compounds such as acetone and methyl ethyl ketone; and cyclic ether compounds such as tetrahydrofuran and dioxane. Among these, it is preferable to use water as a solvent.

When performing the addition reaction of the compound A and hypophosphorous acid (salt) using water as a solvent, it is necessary to use a water-soluble radical polymerization initiator to remove insoluble components after the reaction. It is preferable because there is no. For example, persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate; hydrogen peroxide; organic peroxides such as t-butyl hydroperoxide; 2,2′-azobis-2-methylpropionamidine hydrochloride, etc. Azoamidine compounds, cyclic azoamidine compounds such as 2,2′-azobis-2- (2-imidazolin-2-yl) propane hydrochloride, azonitrile compounds such as 2-carbamoylazoisobutyronitrile, 2,4′-azobis { Azoamide compounds such as 2-methyl-N- [2- (1-hydroxybutyl)] propionamide}, macroazo compounds such as esters of 4,4′-azobis (4-cyanovaleric acid) and (alkoxy) polyethylene glycol Water-soluble azo initiators such as these can be used, and one or more of these can be used. Among these, a persulfuric acid-based initiator is preferable.

The phosphorus atom-containing polyalkylene glycol compound has a function as a chain transfer agent, and the present invention is obtained by radical polymerization of an unsaturated monocarboxylic acid monomer using the compound as a chain transfer agent. The polyalkylene glycol block copolymer can be easily and efficiently produced at a low cost.
Since the step of radically polymerizing the unsaturated monocarboxylic acid monomer can be performed in the same manner as the block polymerization step using the PAG thiol compound as a chain transfer agent, detailed description thereof is omitted.

As described above, the polyalkylene glycol block copolymer for cement admixture of the present invention can exhibit extremely high cement dispersion performance. Thus, the cement admixture containing the polyalkylene glycol block copolymer for cement admixture 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.

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; 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 polyalkylene 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 region, that is, a water / cement ratio. (Mass ratio) = 0.15 to 0.5 (preferably 0.15 to 0.4) can be used even in a low water / cement ratio region, and the unit cement amount is large and the water / cement ratio is small. It is effective for both high-strength concrete and poor-mixed concrete having 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 above cement admixture is used in a cement composition, the blending ratio is such that the polyalkylene glycol block copolymer, which is an essential component of the present invention, is 100% by mass of the total mass of cement in terms of solid content. Therefore, it is preferable to set it to be 0.01 to 10% by mass. 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 polyalkylene 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, fats and oils, 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.

<Polyalkylene glycol block copolymer>
In the polyalkylene glycol block copolymer according to the present invention, a polymer chain (A) based on an unsaturated carboxylic acid monomer unit and a polymer chain (B) based on a polyalkylene glycol structural unit are bonded to a bonding site ( A polyalkylene glycol block copolymer essentially comprising a structure bonded via X),
The polyalkylene 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 average addition mole number of the oxyalkylene group of the polyalkylene glycol structural unit in the polymer chain (B) is 70 or more.

Hereinafter, among the technical features of the polyalkylene glycol block copolymer of the present invention, differences from the above-described technical features of the polyalkylene glycol block copolymer for cement admixture according to the present invention will be described.

The use of the polyalkylene glycol block copolymer according to the present invention is not limited to cement admixture.
The polyalkylene 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 gypsum, it can also be suitably used as a dispersant for dispersing inorganic fine particles.
A dispersant containing such a polyalkylene glycol block copolymer of the present invention is also one aspect of the present invention.

In the polyalkylene glycol block copolymer according to the present invention, the average added mole number of the oxyalkylene group of the polyalkylene glycol structural unit in the polymer chain (B) is 70 or more.
When the average number of added moles of the oxyalkylene group is 70 or more, the above-described copolymer can more fully exhibit the performance based on the polymer chain (B) based on the polyalkylene glycol structural unit. More preferably, it is 80 or more, More preferably, it is 100 or more, More preferably, it is 120 or more, More preferably, it is 150 or more, More preferably, it is 200 or more.
The upper limit of the average number of moles added of the oxyalkylene group is not particularly limited, but is preferably 1000, more preferably 800, still more preferably 500, and still more preferably 300, More preferably, it is 250.

The method for producing the polyalkylene glycol block copolymer according to the present invention can be the same as the method for producing the polyalkylene glycol block copolymer for cement admixture according to the present invention. When producing the polyalkylene glycol block copolymer according to the present invention, a polymer chain (B) having a polyalkylene glycol structural unit having an average alkylene oxide repeating number of 70 or more is used.

The polyalkylene glycol block copolymer for cement admixture of the present invention has the above-described configuration, and includes a polymer chain (A) composed of an unsaturated carboxylic acid monomer unit and a polymer composed of a polyalkylene glycol based unit. A polyalkylene glycol block copolymer for a cement admixture, which has a structure in which a chain (B) is bonded via a bonding site (X),
The above polyalkylene glycol block copolymer for cement admixture 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 average addition mole number of the oxyalkylene group of the polyalkylene glycol-based structural unit in the polymer chain (B) is 25 or more, and is excellent in performance such as cement dispersibility (water reduction) and slump flow. It can be used for cement admixture applications.
In addition, the polyalkylene glycol block copolymer of the present invention has the above-described configuration, and includes a polymer chain (A) composed of unsaturated carboxylic acid monomer units and a polymer chain composed of polyalkylene glycol based units ( B) is a polyalkylene glycol block copolymer having a structure in which it is bound via the binding site (X),
The polyalkylene 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 average addition mole number of the oxyalkylene group of the polyalkylene glycol structural unit in the polymer chain (B) is 70 or more, and is excellent in performance such as cement dispersibility (water reduction) and slump flow. In addition to being used for cement admixture, it can also be suitably used as a dispersant for dispersing inorganic fine particles.

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.
<Measurement of consumption rate of polyethylene glycol by LC>
Device: Waters Alliance (2695)
Analysis software: Waters Empower 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: 1.0 mL / min Column temperature: 40 ° C.
Sample solution injection amount: 100 μL (eluent solution having a sample concentration of 1 to 2% by mass)

<Measurement of PAG thiol compound by GPC>
The monomer amount and multimer amount of the PAG thiol compound were measured under the following measurement conditions.
Device: Waters Alliance (2695)
Analysis software: Waters, Empor professional + GPC option column: Tosoh Co., Ltd., TSKguardcolumnsSWXL + 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. Standard material for preparing a calibration curve: polyethylene glycol (peak top molecular weight (Mp ) 272500, 219300, 107000, 50000, 24000, 12600, 7100, 4250, 1470)
Calibration curve: Flow rate prepared by cubic equation based on Mp value of polyethylene glycol and elution time: 1 mL / min Column temperature: 40 ° C
Measurement time: 45 minutes Sample solution injection amount: 100 μL (PAG, PAG thiol compound is an eluent solution having a sample concentration of 0.4 mass%)

<Measurement of polymer by GPC>
The weight average molecular weight, number average molecular weight, and peak top molecular weight of the polymer were measured under the following measurement conditions.
Device: Waters Alliance (2695)
Analysis software: Waters, Empor professional + GPC option column: Tosoh Corporation, TSKgel guardcolumn α + TSKgel α-5000 + TSKgel α-4000 + TSKgel α-3000
Detector: differential refractometer (RI) detector (Waters 2414), multi-wavelength visible ultraviolet (PDA) detector (Waters 2996)
Eluent: A solution prepared by dissolving 74.2 g of boric acid and 80.0 g of 30% aqueous NaOH in a mixed solvent of 11846 g of water and 3000 g of acetonitrile. Calibration standard: Polyethylene glycol (peak top molecular weight (Mp) 272500, 219300, 107,000, 50000, 24000, 12600, 7100, 4250, 1470)
Calibration curve: Flow rate prepared by cubic equation based on Mp value of polyethylene glycol and elution time: 1 mL / min Column temperature: 40 ° C
Measurement time: 75 minutes Sample solution injection amount: 100 μL (the polymer is an eluent solution having a sample concentration of 0.5% by mass)

(GPC analysis conditions)
In the obtained RI chromatogram, the portions that were flat and stable in the baseline immediately before and after elution of the polymer were connected by straight lines, and the polymer was detected and analyzed. However, when the peak of monomer or monomer-derived impurities is measured partially overlapping with the polymer peak, the polymer part and the monomer part are separated by vertical division at the most concave part of the overlapping part between them and the molecular weight of the polymer part only -The molecular weight distribution was measured. When the polymer part and the other part completely overlapped and could not be separated, the calculation was made collectively.
Further, as a measure of the yield of the polymer, the “polymer purity (hereinafter sometimes abbreviated as“ P% ”)” was calculated from the ratio of the peak area measured by the RI detector as follows.
Polymer purity = (Polymer peak area) / (Polymer peak area + monomer or impurity peak area)

<Solid content measurement conditions>
About 0.5 g of the sample was weighed on an aluminum dish and diluted with about 1 g of water to spread it uniformly. After drying at 130 ° C. for 1 hour under a nitrogen atmosphere and allowing to cool in a desiccator, the weight was measured after drying. The solid content (nonvolatile content) concentration was calculated from the weight difference before and after drying.
As the concentration of the synthesized PAG thiol compound or the aqueous solution of the polymer, the solid content measured by the above procedure was used unless otherwise specified.

<Production Example 1: Production of PAG thiol compound (1)>
(1) Dehydration esterification reaction process In a glass reactor equipped with a Dean-Stark device with a Dimroth condenser, a Teflon (R) stirring blade and a stirring seal, and a temperature sensor with a glass protective tube, Polyethylene glycol having an average addition mole number of ethylene oxide of 77 (PEG 3400, manufactured by MP. Biomedical, 1000 g), 3-mercaptoisobutyric acid (MiBA, manufactured by Tokyo Chemical Industry Co., Ltd., 77.76 g), p-toluenesulfonic acid monohydrate ( PTS · 1H ₂ O, manufactured by Wako Pure Chemical Industries, Ltd., 21.56 g), phenothiazine (PTZ, manufactured by Wako Pure Chemical Industries, Ltd., 0.5389 g), and cyclohexane (CyH, 53.89 g) 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 quickly reacted with an aqueous solution in which water (1023.32 g) was added to 30% NaOH aqueous solution (14.35 g). It was put into the vessel. Subsequently, the temperature was gradually raised to about 100 ° C., and cyclohexane was distilled off. The heating was stopped and nitrogen was bubbled at 30 mL / min for 90 minutes while cooling to remove residual cyclohexane to obtain an aqueous solution of PAG thiol compound (1).
As a result of LC analysis of the obtained target compound, the consumption rate of polyethylene glycol (PEG 3400) was 95.0%, and the average number of SH introduced per molecule of polyethylene glycol (PEG 3400) was 1.88. From this, the molecular weight was set to 3592. From the GPC analysis results, the monomer amount was 92.32%, and the remainder was a multimer.

<Production Example 2: Production of PAG thiol compound (2)>
(1) Dehydration esterification reaction process In a glass reactor equipped with a Dean-Stark device with a Dimroth condenser, a Teflon (R) stirring blade and a stirring seal, and a temperature sensor with a glass protective tube, Polyethylene glycol having an average addition mole number of ethylene oxide of 136 (PEG 6000, manufactured by Wako Pure Chemical Industries, Ltd., 1000 g), 3-mercaptoisobutyric acid (MiBA, manufactured by Tokyo Chemical Industry Co., Ltd., 44.06 g), p-toluenesulfonic acid monohydrate Japanese products (PTS · 1H ₂ O, manufactured by Wako Pure Chemical Industries, Ltd., 20.88 g), phenothiazine (PTZ, manufactured by Wako Pure Chemical Industries, Ltd., 0.5220 g), cyclohexane (CyH, 52.20 g). Prepared. 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 quickly reacted with an aqueous solution in which water (998.43 g) was added to 30% NaOH aqueous solution (13.91 g). It was put into the vessel. Subsequently, the temperature was gradually raised to about 100 ° C., and cyclohexane was distilled off. Heating was stopped and nitrogen was bubbled at 30 mL / min for 90 minutes while cooling to remove residual cyclohexane to obtain an aqueous solution of PAG thiol compound (2).
As a result of LC analysis of the obtained target compound, the consumption rate of polyethylene glycol (PEG 6000) was 97.1%, and the average number of SH introduced per molecule of polyethylene glycol (PEG 6000) was 1.90. From this, the molecular weight was 6194. From the GPC analysis results, the monomer amount was 91.70%, and the remainder was a multimer.

<Production Example 3: Production of PAG thiol compound (3)>
(1) Dehydration esterification reaction process In a glass reactor equipped with a Dean-Stark device with a Dimroth condenser, a Teflon (R) stirring blade and a stirring seal, and a temperature sensor with a glass protective tube, Polyethylene glycol having an average addition mole number of ethylene oxide of 23 (PEG 1000, manufactured by Wako Pure Chemical Industries, Ltd., 1000 g), 3-mercaptoisobutyric acid (MiBA, manufactured by Tokyo Chemical Industry Co., Ltd., 264.37 g), p-toluenesulfonic acid monohydrate Japanese products (PTS · 1H ₂ O, Wako Pure Chemical Industries, 25.28 g), phenothiazine (PTZ, Wako Pure Chemical Industries, 0.6322 g), cyclohexane (CyH, 63.22 g) Prepared. 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 and refluxing while distilling off water for 47.0 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 in which water (1161.17 g) was added to a 30% NaOH aqueous solution (16.84 g) was quickly reacted. It was put into the vessel. Subsequently, the temperature was gradually raised to about 100 ° C., and cyclohexane was distilled off. The heating was stopped and nitrogen was bubbled at 30 mL / min for 90 minutes while cooling to remove residual cyclohexane to obtain an aqueous solution of PAG thiol compound (3).
As a result of LC analysis of the obtained target compound, the consumption rate of polyethylene glycol (PEG 1000) was 97.00%, and the average number of SH introduced per molecule of polyethylene glycol (PEG 1000) was 1.92. From this, the molecular weight was 1196. From the GPC analysis results, the monomer amount was 95.62%, and the remainder was a multimer.

<Example 1: Production of polymer (1)>
As a monomer solution (A), ion exchange water was added to methacrylic acid (MAA, 25.04 g) and a 30% aqueous sodium hydroxide solution (1.05 g) to make a total of 32.35 g.
PAG thiol compound (1) obtained in Production Example 1 (24.03 g, but in terms of solid content) and ion-exchanged water were added to prepare a PAG thiol compound aqueous solution totaling 83.20 g.
As an initiator solution, a solution was prepared by adding ion-exchanged water to 2,2′-azobis-2-methylpropionamidine hydrochloride (V-50, 0.24 g, manufactured by Wako Pure Chemical Industries, Ltd.) to make a total of 50 g. .
A glass reactor equipped with a Dimroth condenser, a Teflon (R) stirrer and a stirrer with a stirring seal, a nitrogen inlet tube, and a temperature sensor was charged with 68.57 g of ion-exchanged water. While introducing at 200 mL / min, the mixture was heated to 80 ° C.
Subsequently, the monomer solution (A) and the PAG thiol compound aqueous solution were dropped into the reaction vessel over 3 hours and the initiator solution over 3.5 hours. The polymerization reaction was completed by maintaining at 80 ° C. for 1 hour after completion of the dropping. After cooling to room temperature, an aqueous solution of polymer (1) was obtained.
As a result of GPC analysis, the polymer was Mw = 23300, Mp = 19200, and Mn = 18900. The pure polymer content was 96.53%.
The average addition mole number (n) of the oxyalkylene group of the polymer (1) was 77, and the average introduction mole number (m1 + m2) of the monocarboxylic acid structural unit was 42.

<Example 2: Production of polymer (2)>
As a monomer solution (A), ion exchange water was added to methacrylic acid (MAA, 20.48 g) and a 30% aqueous sodium hydroxide solution (0.86 g) to make a total of 26.46 g.
PAG thiol compound (2) obtained in Production Example 2 (28.76 g, but in terms of solid content) and ion-exchanged water were added to prepare a PAG thiol compound aqueous solution totaling 98.40 g.
As an initiator solution, a solution was prepared by adding ion exchange water to 2,2′-azobis-2-methylpropionamidine hydrochloride (V-50, 0.20 g, manufactured by Wako Pure Chemical Industries, Ltd.) to make a total of 50 g. .
A glass reactor equipped with a Dimroth condenser, a Teflon (R) stirrer and a stirrer with a stirring seal, a nitrogen inlet tube, and a temperature sensor was charged with 68.57 g of ion-exchanged water. While introducing at 200 mL / min, the mixture was heated to 80 ° C.
Subsequently, the monomer solution (A) and the PAG thiol compound aqueous solution were dropped into the reaction vessel over 3 hours and the initiator solution over 3.5 hours. The polymerization reaction was completed by maintaining at 80 ° C. for 1 hour after completion of the dropping. After cooling to room temperature, an aqueous solution of the polymer (2) was obtained.
As a result of GPC analysis, the polymer was Mw = 27600, Mp = 24000, and Mn = 21600. The pure polymer content was 97.76%.
The average addition mole number (n) of the oxyalkylene group of the polymer (2) was 136, and the average introduction mole number (m1 + m2) of the monocarboxylic acid structural unit was 63.

<Comparative Example 1: Production of comparative polymer (1)>
As monomer solution (A), ion exchange water was added to methacrylic acid (MAA, 25.01 g) and 30% aqueous sodium hydroxide solution (1.05 g) to make a total of 32.31 g.
PAG thiol compound (3) obtained in Production Example 3 (23.60 g, in terms of solid content) and ion-exchanged water were added to prepare a PAG thiol compound aqueous solution totaling 83.31 g.
As an initiator solution, a solution was prepared by adding ion-exchanged water to 2,2′-azobis-2-methylpropionamidine hydrochloride (V-50, 0.25 g, manufactured by Wako Pure Chemical Industries, Ltd.) to make a total of 50 g. .
A glass reactor equipped with a Dimroth condenser, a Teflon (R) stirrer and a stirrer with a stirring seal, a nitrogen inlet tube, and a temperature sensor was charged with 68.57 g of ion-exchanged water. While introducing at 200 mL / min, the mixture was heated to 80 ° C.
Subsequently, the monomer solution (A) and the PAG thiol compound aqueous solution were dropped into the reaction vessel over 3 hours and the initiator solution over 3.5 hours. The polymerization reaction was completed by maintaining at 80 ° C. for 1 hour after completion of the dropping. After cooling to room temperature, an aqueous solution of comparative polymer (1) was obtained.
As a result of GPC analysis, the polymer was Mw = 15600, Mp = 11700, and Mn = 1100. The pure polymer content was 94.59%.
The average addition mole number (n) of the oxyalkylene group of the comparative polymer (1) was 23, and the average introduction mole number (m1 + m2) of the monocarboxylic acid structural unit was 14.

<Concrete test>
Using the polymers produced in Examples 1 and 2 and Comparative Example 1 as a cement admixture, the concrete slump flow value and the amount of air were measured as follows.

(1) Used material cement: Ordinary Portland cement made by Taiheiyo Cement Co., Ltd. Coarse aggregate: Ome crushed fine aggregate: Oigawa river sand (specific gravity 2.59) / Chiba prefecture Kimitsu mountain sand (specific gravity 2.53) weight ratio 9: (2) Unit amount (kg / m ³ )
W / C = 53.1
s / a = 47.0
Air = 45.0
Water = 170.0
Cement = 320
Stone = 942
Sand = 865
(3) Mixer used: Taiheiyo Kiko, TM55 (55 liter forced kneading bread type mixer), kneading amount 30 liter (4) Test method MA202 (Pozoris product) was used as an AE agent and MA404 (Pozoris product) was used as an antifoaming agent. . Fine aggregate and cement are put into a mixer and kneaded for 10 seconds. Next, cement admixture, AE agent, water containing antifoaming agent, and coarse aggregate are put in. After kneading for 60 seconds, concrete is mixed. Was discharged.
The slump flow value and the amount of air of the obtained concrete were measured in accordance with Japanese Industrial Standards (JIS A1101-2005, A1128-2005, A6204-2006). In addition, it shows that the fluidity | liquidity of concrete is so high that a slump flow value is large. If the slump flow value is the same, an admixture with a smaller addition amount indicates better cement dispersion performance and higher water reduction performance.

The results of the concrete test are shown in Table 1.
The blending amounts of the cement admixture, the defoaming agent (MA404) and the AE agent (MA202) were calculated as solid contents and are shown in Table 1 in terms of% (mass%) with respect to the cement mass.

In Comparative Example 1 in which the average added mole number (n) of the oxyalkylene group of the copolymer was small, the slump flow value was small.
On the other hand, in Examples 1 and 2 to which the copolymer of the present invention having a large average addition mole number (n) of oxyalkylene groups was added, the slump flow value was large.
From the above, it has become clear that the copolymer of the present invention is a polymer that can be suitably used as a cement admixture.

Claims (10)

Cement admixture with a structure in which a polymer chain (A) composed of an unsaturated carboxylic acid monomer unit and a polymer chain (B) composed of a polyalkylene glycol structural unit are bonded via a bonding site (X) A polyalkylene glycol block copolymer for an agent,
The polyalkylene glycol block copolymer for cement admixture 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 average addition mole number of the oxyalkylene group of the polyalkylene glycol constituent units in the polymer chain (B) is Ri der 25 or more,
Polymer chain (A) in the unsaturated carboxylic acid monomer average introduction number of moles of units throughout the copolymer for cement admixture, characterized in 20-500 der Rukoto polyalkylene glycol block copolymerization Coalescence. The polyalkylene glycol block copolymer for cement admixture according to claim 1, wherein the bonding site (X) of the polyalkylene glycol block copolymer for cement admixture has a sulfur atom. The polyalkylene glycol block copolymer for cement admixture has an average added mole number of oxyalkylene groups of the polyalkylene glycol structural unit in the polymer chain (B) of 70 or more. Item 3. The polyalkylene glycol block copolymer for cement admixture according to Item 1 or 2. A cement admixture comprising the polyalkylene glycol block copolymer for cement admixture according to any one of claims 1 to 3. A cement composition comprising the cement admixture according to claim 4, cement and water. A polyalkylene having a structure in which a polymer chain (A) based on an unsaturated carboxylic acid monomer unit and a polymer chain (B) based on a polyalkylene glycol structural unit are bonded via a binding site (X) A glycol-based block copolymer,
The polyalkylene 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,
Der the average addition mole number of the oxyalkylene group of the polyalkylene glycol structural unit of 70 or more in the polymer chain (B) is,
Polyalkylene glycol block copolymer having an average introduction number of moles of the unsaturated carboxylic acid-based monomer unit in the polymer chain (A) is characterized by 20-500 der Rukoto throughout the copolymer. The polyalkylene glycol block copolymer according to claim 6, wherein the bonding site (X) has a sulfur atom. A dispersant comprising the polyalkylene glycol block copolymer according to claim 6. A cement admixture comprising the polyalkylene glycol block copolymer according to claim 6 or 7. A cement composition comprising the cement admixture according to claim 9, cement and water.