JP6819321B2 - A method for producing a cement composition. - Google Patents

Description

The present invention relates to a method for producing a cement composition.

In order to improve the workability and durability of the cement composition, it is effective to reduce the unit water amount in the cement composition. However, it is known that when the unit water amount is reduced, the fluidity of the cement composition is lowered and the workability is impaired. Therefore, in order to ensure the efficient workability of the cement composition even when the unit water amount is reduced, various dispersants having a function of dispersing cement particles are used.

Furthermore, in recent years, as the number of ready-mixed concrete factories has decreased, the transportation distance and transportation time of concrete have increased. Therefore, various dispersants having a function of maintaining the slump retention of cement compositions have been developed, and after kneading, they have been developed. A method for producing a cement composition having arbitrary fluidity has also been developed by appropriately adding a cement admixture (hereinafter referred to as post-addition) to the cement composition having fluidity.

Patent Documents 1, 2 and 3 exemplify copolymers having a specific unsaturated polyalkylene glycol-based monomer and a specific unsaturated carboxylic acid ester-based monomer.

Patent Document 4 exemplifies an admixture for a water-hard composition containing two types of copolymers of a specific unsaturated polyalkylene glycol-based monomer and a specific unsaturated carboxylic acid-based monomer, and polyethylene glycol. Has been done.

These dispersants include a unit that adsorbs to cement particles and exerts dispersibility relatively early, and a unit that exposes the adsorbent group to cement after a lapse of time, and the initial water reduction of concrete. It is said that the slump retention can be satisfied.

Further, Patent Document 5 exemplifies a pump pumping aid in which oxycarboxylic acid or a salt thereof is granulated or flaked, and this admixture is said to have a slump retention for a long time.

Japanese Unexamined Patent Publication No. 10-81549 Japanese Unexamined Patent Publication No. 2009-096672 JP-A-2009-173527 Japanese Unexamined Patent Publication No. 2013-151403 Japanese Unexamined Patent Publication No. 2000-191354

However, with the cement admixtures described in Patent Documents 1 to 4, it is possible to maintain the slump retention of the cement composition, but the cement admixture exhibits the fluidity of the cement composition immediately after the post-addition. As a result, the slump retention cannot be maintained for a long time. Therefore, it cannot be suitably used as a cement admixture for post-addition, which is post-added to the fluid cement composition after kneading, which has been required in recent years. Further, the cement admixture described in Patent Document 5 can maintain the slump retention for a long time, but delays the initial strength development of the cement composition and tends to generate bleeding water. There is a problem in using it as a cement admixture for post-addition. Therefore, there is a demand for a method for producing a cement composition using a cement admixture for post-addition, which does not change the water reduction immediately after post-addition, does not delay the development of initial strength, and can further suppress bleeding water. ing.

Therefore, in order to solve the above-mentioned problems, the present invention has excellent long-term slump retention performance even when added to a fluid cement composition after a certain period of time has passed after kneading, and the initial strength of the cement composition is developed. It is an object of the present invention to provide a method for producing a cement composition using a cement admixture for post-addition, which is excellent and can suppress the generation of bleeding water.

As a result of diligent studies to achieve the above object, the present inventors have made a constituent unit having an alkenyl group having a specific carbon atom number and a constituent unit of an unsaturated monocarboxylic acid ester system having a specific carbon atom number. The above problem is solved by using a polycarboxylic acid copolymer containing a constituent unit derived from a saturated carboxylic acid monomer or a cement admixture containing a salt (A) thereof as a cement admixture for post-addition. This led to the present invention.

That is, the present invention is the following [1] to [5].
[1] A method for producing a cement composition, which comprises performing the following steps (1) and (2).
Step (1): A step of adding a cement admixture (D) to a base cement containing a hydraulic material and kneading it.
Step (2): A step of adding and kneading a cement admixture for post-addition containing at least the following component (A) component: a polycarboxylic acid-based copolymer or a salt (A) thereof after the kneading for 5 minutes or more.
(A) Ingredient:
Monomer (I) 1 to 97% by weight represented by the following general formula (1), monomer (II) 1 to 97% by weight represented by the following general formula (2), the following general formula (3) Copolymerized with monomers (III) 1 to 97% by weight, unsaturated carboxylic acid-based monomers (IV) 0.1 to 50% by weight, and monomers (I) to (IV). A polycarboxylic acid-based copolymer or a salt (A) thereof obtained by copolymerizing 0 to 50% by weight of other possible monomers (V).
R ^{1 −} O − (A ¹ O) _{n1 −} R ² ··· (1)
(In the formula, R ¹ represents an alkenyl group having 2 to 5 carbon atoms. A ¹ O represents an oxyalkylene group having 2 to 18 carbon atoms, which is the same or different. N 1 represents an oxyalkylene group. It is the average number of added moles and represents a number of 1 to 200. R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.)

（式中、Ｒ³、Ｒ⁴およびＲ⁵は、それぞれ独立に、水素原子または炭素原子数１〜３のアルキル基を表す。ｍは、０〜２の数を表す。Ａ²Ｏは、同一若しくは異なって、炭素原子数２〜１８のオキシアルキレン基を表す。ｎ２は、オキシアルキレン基の平均付加モル数であり、６〜２００の数を表す。Ｘは、水素原子または炭素原子数１〜３０の炭化水素基を表す。）

(In the formula, R ³ , R ⁴ and R ⁵ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. M represents a number from 0 to ^2. A ² O is the same. Or differently, it represents an oxyalkylene group having 2 to 18 carbon atoms. N2 is the average number of moles of the oxyalkylene group added, and represents a number of 6 to 200. X is a hydrogen atom or 1 to 1 carbon atom. Represents 30 hydrocarbon groups.)

（式中、Ｒ⁶、Ｒ⁷およびＲ⁸は、それぞれ独立に、水素原子または炭素原子数１〜３のアルキル基を表す。Ｙは、ヘテロ原子を含んでよい炭素原子数１〜１０の炭化水素基を表す。）
〔２〕前記ポリカルボン酸系共重合体またはその塩（Ａ）の単量体（ＩＩＩ）中のＹが、メチル基、エチル基、イソプロピル基、２−ヒドロキシエチル基、２−ヒドロキシプロピル基、２−ヒドロキシ−１−メチルエチル基から選ばれる少なくとも一つの単量体を含む〔１〕に記載のセメント組成物の製造方法。
〔３〕前記ポリカルボン酸系共重合体またはその塩（Ａ）の不飽和カルボン酸系単量体（ＩＶ）がアクリル酸またはその塩、メタクリル酸またはその塩、マレイン酸またはその塩から選ばれる少なくとも一つの単量体を含む〔１〕〜〔２〕のいずれかに記載のセメント組成物の製造方法。
〔４〕前記ポリカルボン酸系共重合体またはその塩（Ａ）の重量平均分子量が、ポリエチレングリコール換算で５，０００〜６０，０００である〔１〕〜〔３〕のいずれかに記載のセメント組成物の製造方法。
〔５〕前記セメント混和剤（Ｄ）が、下記（Ｂ）成分：ポリカルボン酸系共重合体またはその塩（Ｂ）および／または（Ｃ）成分：ポリカルボン酸系共重合体またはその塩（Ｃ）を含有する〔１〕〜〔４〕いずれかに記載のセメント組成物の製造方法。
（Ｂ）成分：
単量体（Ｉ）および単量体（ＩＶ）を、または、単量体（Ｉ）、単量体（ＩＶ）ならびに単量体（Ｉ）および（ＩＶ）と共重合可能なその他の単量体（ＶＩ）を、共重合させることにより得られるポリカルボン酸系共重合体またはその塩（Ｂ）。
（Ｃ）成分：
単量体（ＩＩ）および単量体（ＩＶ）を、または、単量体（ＩＩ）、単量体（ＩＶ）ならびに単量体（ＩＩ）および（ＩＶ）と共重合可能なその他の単量体（ＶＩＩ）を、共重合させることにより得られるポリカルボン酸系共重合体またはその塩（Ｃ）。

(In the formula, R ⁶ , R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Y is a carbonization having 1 to 10 carbon atoms which may contain a hetero atom. Represents a hydrogen group.)
[2] Y in the monomer (III) of the polycarboxylic acid-based copolymer or its salt (A) is a methyl group, an ethyl group, an isopropyl group, a 2-hydroxyethyl group, a 2-hydroxypropyl group, The method for producing a cement composition according to [1], which comprises at least one monomer selected from a 2-hydroxy-1-methylethyl group.
[3] The unsaturated carboxylic acid-based monomer (IV) of the polycarboxylic acid-based copolymer or its salt (A) is selected from acrylic acid or a salt thereof, methacrylic acid or a salt thereof, maleic acid or a salt thereof. The method for producing a cement composition according to any one of [1] to [2], which comprises at least one monomer.
[4] The cement according to any one of [1] to [3], wherein the weight average molecular weight of the polycarboxylic acid-based copolymer or its salt (A) is 5,000 to 60,000 in terms of polyethylene glycol. Method for producing the composition.
[5] The cement admixture (D) contains the following component (B): polycarboxylic acid-based copolymer or salt thereof (B) and / or component (C): polycarboxylic acid-based copolymer or salt thereof ( The method for producing a cement composition according to any one of [1] to [4], which contains C).
(B) Ingredient:
Monomer (I) and monomer (IV), or other monomer capable of copolymerizing with monomer (I), monomer (IV) and monomer (I) and (IV) A polycarboxylic acid-based copolymer obtained by copolymerizing a body (VI) or a salt (B) thereof.
(C) component:
Monomer (II) and monomer (IV), or other monomer capable of copolymerizing with monomer (II), monomer (IV) and monomer (II) and (IV) A polycarboxylic acid-based copolymer obtained by copolymerizing a body (VII) or a salt (C) thereof.

According to the present invention, even when added to a fluid cement composition after a certain period of time has passed after kneading, the slump retention performance for a long time is excellent, the initial strength of the cement composition is excellent, and bleeding water is generated. A method for producing a cement composition using a cement admixture for post-addition is provided.

That is, the present invention is a method for producing a cement composition, which comprises performing the following steps (1) and (2).
Step (1): A step of adding a cement admixture (D) to a base cement containing a hydraulic material and kneading it.
Step (2): A step of adding and kneading a cement admixture for post-addition containing at least the component (A) described later after the kneading for 5 minutes or more.

In the above method for producing a cement composition, by adding a specific cement admixture for post-addition, which will be described later, after the initial kneading in step (1), the initial strength of the cement is exhibited and the slump holding performance for a long time is excellent. Moreover, it was discovered for the first time that a cement composition in which the generation of bleeding water was suppressed could be obtained.

The time for adding the cement admixture for post-addition in the step (2) is important after 5 minutes or more have passed from the step (1), preferably in the elapsed range of 5 to 60 minutes, and more preferably 10 to 40 minutes. The elapsed range of minutes. By satisfying this range, the cement composition can maintain slump retention for a long time.

<Cement composition (D)>
The cement admixture (D) is intended to be mixed (initial addition) before kneading the cement composition, and therefore, there is no particular limitation as long as it exhibits initial water reduction and dispersibility. Examples of such a substance include those containing a polycarboxylic acid-based copolymer or a lignin sulfonic acid-based compound as an active ingredient.

<Ingredient (A)>
The component (A) of the present invention contains 1 to 97% by weight of the monomer (I) represented by the general formula (1) and 1 to 97% by weight of the monomer (II) represented by the general formula (2). , 1 to 97% by weight of the monomer (III) represented by the general formula (3), 0.1 to 50% by weight of the unsaturated carboxylic acid monomer (IV), and (I) to (IV). A polycarboxylic acid-based copolymer or a salt (A) thereof obtained by copolymerizing 0 to 50% by weight of another polymerizable monomer (V).

Component (A): The compounding ratio of each monomer when obtaining the polycarboxylic acid-based copolymer or the salt (A) thereof is as follows. The blending ratio of the monomer (I) is 1% by weight to 97% by weight, preferably 3% by weight to 90% by weight, and more preferably 5% by weight to 70% by weight.

The blending ratio of the monomer (II) is 1% by weight to 97% by weight, preferably 5% by weight to 97% by weight, and more preferably 5% by weight to 90% by weight.

The blending ratio of the monomer (III) is 1% by weight to 97% by weight, preferably 3% by weight to 90% by weight, and more preferably 5% by weight to 70% by weight.

The compounding ratio of the monomer (IV) is 0.1% by weight to 50% by weight, preferably 0.1% by weight to 40% by weight, and more preferably 0.1% by weight to 30% by weight. is there.
The compounding ratio of the monomer (V) is 0% by weight to 50% by weight, preferably 0% by weight to 40% by weight.

The above-mentioned compounding ratio is the compounding ratio of the monomer (I) + the compounding ratio of the monomer (II) + the compounding ratio of the monomer (III) + the compounding ratio of the monomer (IV) + the monomer. It is the compounding ratio when the compounding ratio of (V) = 100% by weight.

In the component (A): polycarboxylic acid-based copolymer or salt (A) thereof, the ratio of the blending amount of the monomer (II) to the blending amount of the monomer (I) is preferably 1% by weight to 1000% by weight. % By weight. The ratio of the blending amount of the monomer (III) to the blending amount of the monomer (I) is preferably 1% by weight to 1000% by weight. The ratio of the blending amount of the monomer (IV) to the blending amount of the monomer (I) is preferably 0.001% by weight to 700% by weight. The ratio of the blending amount of the monomer (V) to the blending amount of the monomer (I) is preferably 0% by weight to 30% by weight, and more preferably 0% by weight to 20% by weight.

Hereinafter, the monomer (I) will be described first.

The monomer (I) is a polyalkylene glycol monoalkenyl ether represented by the following general formula (1).

R ^{1 −} O − (A ¹ O) _{n1 −} R ² ··· (1)
(In the formula, R ¹ represents an alkenyl group having 2 to 5 carbon atoms. A ¹ O represents an oxyalkylene group having 2 to 18 carbon atoms, which is the same or different. N 1 represents an oxyalkylene group. It is the average number of added moles and represents a number of 1 to 200. R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.)

R ¹ in the general formula (1) represents an alkenyl group having 2 to 5 carbon atoms. The number of carbon atoms of the alkenyl group is preferably 3 to 5. Examples of R ¹ include, but are not limited to, allyl groups, metharyl groups, residues of 3-methyl-3-butene-1-ol, and the like.

A ¹ O in the general formula (1) represents an oxyalkylene group having 2 to 18 carbon atoms, which is the same or different. Examples of the oxyalkylene group include an oxyethylene group (ethylene glycol unit), an oxypropylene group (propylene glycol unit), and an oxybutylene group (butylene glycol unit), and an oxyethylene group (ethylene glycol unit) and oxypropylene. Groups (propylene glycol units) are preferred.

The above "same or different" means that when a plurality of A ¹ O are contained in the general formula (1) (when n1 is 2 or more), each A ¹ O may be the same oxyalkylene group. However, it means that they may be different (two or more kinds) oxyalkylene groups. When a plurality of A ¹ O are contained in the general formula (1), an embodiment comprises a group consisting of an oxyethylene group (ethylene glycol unit), an oxypropylene group (propylene glycol unit) and an oxybutylene group (butylene glycol unit). Examples include a mode in which two or more selected oxyalkylene groups are mixed, and a mode in which an oxyethylene group (ethylene glycol unit) and an oxypropylene group (propylene glycol unit) are mixed, or an oxyethylene group (ethylene glycol unit) and oxy. It is preferable that the butylene group (butylene glycol unit) is mixed, and it is more preferable that the oxyethylene group (ethylene glycol unit) and the oxypropylene group (propylene glycol unit) are mixed. In an embodiment in which different oxyalkylene groups are mixed, the addition of two or more types of oxyalkylene groups may be block-like addition or random addition. When an oxyethylene group and an oxypropylene group are mixed, the ratio of the average number of moles of the oxyethylene group to the average number of moles of the oxypropylene group is 50 to 99. It is preferably 9% / 50 to 0.1%.

N1 in the general formula (1) is the average number of moles of the oxyalkylene group added, and represents a number of 1 to 200. n1 is preferably 1 to 70, more preferably 5 to 70, and even more preferably 8 to 70. In the present specification, the average number of moles of oxyalkylene groups added means the average number of moles of alkylene glycol units added to 1 mole of the monomer.

R ² in the general formula (1) represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. If the number of carbon atoms is large, the cement dispersibility of the cement admixture may not be sufficiently exhibited. Therefore, R ² is preferably a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and is preferably a hydrogen atom or a hydrocarbon atom. It is more preferably a hydrocarbon group of number 1-5, most preferably a hydrogen atom or a methyl group.

Examples of the monomer (I) include (poly) ethylene glycol allyl ether, (poly) ethylene glycol metallic ether, (poly) ethylene glycol 3-methyl-3-butenyl ether, and (poly) ethylene (poly) propylene. Glycolallyl ether, (poly) ethylene (poly) propylene glycol metallic ether, (poly) ethylene (poly) propylene glycol 3-methyl-3-butenyl ether, (poly) ethylene (poly) butylene glycol allyl ether, (poly) Ethylene (poly) butylene glycol metallic ether, (poly) ethylene (poly) butylene glycol 3-methyl-3-butenyl ether, methoxy (poly) ethylene glycol allyl ether, methoxy (poly) ethylene glycol metallic ether, methoxy (poly) Ethylene glycol 3-methyl-3-butenyl ether, methoxy (poly) ethylene (poly) propylene glycol allyl ether, methoxy (poly) ethylene (poly) propylene glycol metalyl ether, methoxy (poly) ethylene (poly) propylene glycol 3- Methyl-3-butenyl ether, methoxy (poly) ethylene (poly) butylene glycol allyl ether, methoxy (poly) ethylene (poly) butylene glycol metallic ether, methoxy (poly) ethylene (poly) butylene glycol 3-methyl-3-3 Butenyl ethers, (poly) ethylene glycol (poly) propylene glycol monoallyl ethers, and ethylene oxide propylene oxide adducts of 3-methyl-3-butene-1-ol can be mentioned. As the monomer (I), one or more of these may be used, but since the hydrophilicity and hydrophobicity balance of the copolymer (A) can be made excellent, (poly) It preferably contains one or more selected from ethylene glycol (meth) allyl ether, (poly) ethylene glycol 3-methyl-3-butenyl ether, and (poly) ethylene (poly) propylene glycol allyl ether. The average number of moles of the oxyalkylene group (polyalkylene glycol unit) of the monomer (I) is preferably 1 to 70, more preferably 5 to 70, and further preferably 8 to 70. preferable. In addition, in this specification, "(poly)" means that one or two or more components or raw materials described immediately after that are bonded. Further, in the present specification, "(meth) allyl" means "allyl or metallyl".

The monomer (I) may contain only one type of monomer represented by the general formula (1), or may contain a combination of two or more types.

The monomer (II) is represented by the following general formula (2).

（式中、Ｒ³、Ｒ⁴およびＲ⁵は、それぞれ独立に水素原子または炭素原子数１〜３のアルキル基を表す。ｍは、０〜２の数を表す。Ａ²Ｏは、同一若しくは異なって、炭素原子数２〜１８のオキシアルキレン基を表す。ｎ２は、オキシアルキレン基の平均付加モル数であり、６〜２００の数を表す。Ｘは、水素原子または炭素原子数１〜３０の炭化水素基を表す。）

(In the formula, R ³ , R ⁴ and R ⁵ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. M represents a number of 0 to ^2. A ² O is the same or Differently, it represents an oxyalkylene group having 2 to 18 carbon atoms. N2 is the average number of moles of the oxyalkylene group added and represents a number of 6 to 200. X is a hydrogen atom or 1 to 30 carbon atoms. Represents the hydrocarbon group of.)

R ³ , R ⁴ and R ⁵ in the general formula (2) independently represent hydrogen atoms or alkyl groups having 1 to 3 carbon atoms, respectively.

A ² O in the general formula (2) represents an oxyalkylene group having 2 to 18 carbon atoms, which is the same or different. Examples of the oxyalkylene group include an oxyethylene group (ethylene glycol unit), an oxypropylene group (propylene glycol unit), and an oxybutylene group (butylene glycol unit), and an oxyethylene group (ethylene glycol unit) and oxypropylene. Groups (propylene glycol units) are preferred.

The above-mentioned "same or different" means that each of A ² O in the general formula (2) may be the same oxyalkylene group, or may be a different (two or more kinds) oxyalkylene group. Means that. When a plurality of A ² O are contained in the general formula (2), an embodiment comprises a group consisting of an oxyethylene group (ethylene glycol unit), an oxypropylene group (propylene glycol unit) and an oxybutylene group (butylene glycol unit). Examples include a mode in which two or more selected oxyalkylene groups are mixed, and a mode in which an oxyethylene group (ethylene glycol unit) and an oxypropylene group (propylene glycol unit) are mixed, or an oxyethylene group (ethylene glycol unit) and oxy. It is preferable that the butylene group (butylene glycol unit) is mixed, and it is more preferable that the oxyethylene group (ethylene glycol unit) and the oxypropylene group (propylene glycol unit) are mixed. In an embodiment in which different oxyalkylene groups are mixed, the addition of two or more types of oxyalkylene groups may be block-like addition or random addition.

N2 in the general formula (2) is the average number of moles of the oxyalkylene group added, and represents a number of 6 to 200. n2 is preferably 6 to 150, more preferably 6 to 100, and even more preferably 6 to 70.

The monomer (II) may be one kind of monomer represented by the general formula (2), or may be a combination of two or more kinds.

X in the general formula (2) represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. When the number of carbon atoms is not too large, the dispersibility of the hydraulic composition of the hydraulic composition dispersant is sufficiently exhibited. Therefore, X is preferably a hydrocarbon atom or a hydrocarbon group having 1 to 10 carbon atoms, more preferably a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, and is a hydrogen atom or a methyl group. Is most preferable.

Examples of the monomer (II) include unsaturated monocarboxylic acids such as (meth) acrylate (hereinafter, “(meth) acrylate” means “acrylate or methacrylate”) and (poly) ethylene glycol. , (Poly) ethylene (poly) propylene glycol, (poly) ethylene (poly) butylene glycol, methoxy (poly) ethylene glycol, methoxy (poly) ethylene (poly) propylene glycol, methoxy (poly) ethylene (poly) butylene glycol, etc. Examples thereof include esterified products with (poly) alkylene glycol. Also, for example, (poly) ethylene glycol (meth) acrylate, (poly) ethylene (poly) propylene glycol (meth) acrylate, (poly) ethylene (poly) butylene glycol (meth) acrylate, methoxy (poly) ethylene glycol (meth). Examples thereof include (poly) alkylene glycol (meth) acrylates such as acrylates, methoxy (poly) ethylene (poly) propylene glycol (meth) acrylates, and methoxy (poly) ethylene (poly) butylene glycol (meth) acrylates. As the monomer (II), one or a combination of two or more of these can be used, but it is preferable to use (poly) alkylene glycol (meth) acrylate, and (poly) ethylene glycol (meth). It is more preferable to use at least one of acrylate, (poly) propylene glycol (meth) acrylate and methoxy (poly) ethylene glycol (meth) acrylate. The average number of moles of the (poly) alkylene glycol added is preferably 6 to 200, more preferably 6 to 100, and even more preferably 6 to 70.

The monomer (II) is not particularly limited and can be produced by a known method. Such methods include, for example, unsaturated monocarboxylic acids such as (meth) acrylic acid, (poly) ethylene glycol, (poly) ethylene (poly) propylene glycol, (poly) ethylene (poly) butylene glycol, and methoxy. Examples thereof include a method of esterifying (poly) alkylene glycol such as (poly) ethylene glycol, methoxy (poly) ethylene (poly) propylene glycol, and methoxy (poly) ethylene (poly) butylene glycol.

The monomer (III) is represented by the following general formula (3).

（式中、Ｒ⁶、Ｒ⁷およびＲ⁸は、それぞれ独立に、水素原子または炭素原子数１〜３のアルキル基を表す。Ｙは、ヘテロ原子を含んでよい炭素原子数１〜１０の炭化水素基を表す。）

(In the formula, R ⁶ , R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Y is a carbonization having 1 to 10 carbon atoms which may contain a hetero atom. Represents a hydrogen group.)

R ⁶ , R ⁷ and R ⁸ in the general formula (3) independently represent hydrogen atoms or alkyl groups having 1 to 3 carbon atoms.

Y in the general formula (3) represents a hydrocarbon group having 1 to 10 carbon atoms which may contain a hetero atom. When an atomic group having an atomic group having not too large number of carbon atoms is present in the ester moiety, the slump retention property of the cement admixture and the effect of suppressing bleeding after aging are sufficiently exhibited. Therefore, Y is preferably a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom, and more preferably a hydrocarbon group having 1 to 5 carbon atoms which may contain a heteroatom. Most preferably, it is a hydrocarbon group having 1 to 3 carbon atoms which may contain an atom.

Examples of the monomer (III) include methyl (meth) acrylate, ethyl (meth) acrylate, normal propyl (meth) acrylate, isopropyl (meth) acrylate, normal butyl (meth) acrylate, isobutyl (meth) acrylate, and hydroxy. Methyl (meth) acrylate, 1-hydroxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxy-1-methylethyl acrylate, 1-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) Acrylic, 3-Hydroxypropyl (meth) acrylate, 2-Hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, diethylene glycol (meth) acrylate, dipropylene glycol (meth) acrylate, nitromethyl (meth) acrylate, amino Methyl (meth) acrylate and 2-aminoethyl (meth) acrylate are mentioned, and Y in the general formula (3) is a hydrocarbon group having 1 to 3 carbon atoms which may contain a hetero atom (3). The compound represented by is preferable, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxy-1-methylethyl (meth) acrylate, 2-. Hydroxypropyl (meth) acrylate is preferred.

The monomer (III) is not particularly limited and can be produced by a known method. As such a method, for example, a method of esterifying an unsaturated monocarboxylic acid such as (meth) acrylic acid and an alcohol such as methanol or ethanol, or an epoxy compound such as ethylene oxide or propylene oxide is ring-opened and added. The method can be mentioned.

The copolymer (A) may further contain a structural unit derived from at least one monomer (IV) selected from acrylic acid or a salt thereof, methacrylic acid or a salt thereof, maleic acid or a salt thereof.

Examples of the unsaturated carboxylic acid-based monomer (IV) include monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and salts thereof (for example, monovalent metal salt, divalent metal salt, ammonium salt, etc.). Organic amine salts), dicarboxylic acids such as maleic acid and fumaric acid, and salts thereof (for example, monovalent metal salt, divalent metal salt, ammonium salt, organic amine salt) can be mentioned. The unsaturated carboxylic acid-based monomer (IV) may be one or more of these, preferably two or more of these, and more preferably two or more of these. More preferred. Among them, it is preferable to use at least one monomer selected from acrylic acid or a salt thereof, methacrylic acid or a salt thereof, maleic acid or a salt thereof, and it is more preferable to use two kinds in combination, acrylic acid or a salt thereof. And it is even more preferable to use two kinds selected from methacrylic acid or a salt thereof in combination. When two types (monomer (IV-1) and monomer (IV-2)) are used in combination, the ratio when using the monomer (IV-1) and the monomer (IV-2) ( (The total is 100% by weight), usually (IV-1) / (IV-2) is (0.1% to 99.9%) / (99.9% to 0.1%), which is preferable. Is (1% to 99%) / (99% to 1%). When three types (monomer (IV-1), monomer (IV-2), and monomer (IV-3)) are used in combination, the monomer (IV-1) and the monomer (IV) The ratio (total is 100% by weight) when 2) and the monomer (IV-3) are used is usually (IV-1) / (IV-2) / (IV-3) (0). .1% to 99.9%) / (0.1% to 99.9%) / (0.1% to 99.9%), preferably (1% to 99%) / (1% to 99%) / (1% to 99%).

When acrylic acid is used as the unsaturated carboxylic acid monomer (IV), the ratio of acrylic acid dimer (total is 100% by weight) is acrylic acid monomer / acrylic acid dimer = (90.0% by weight to 100% by weight). %) / (0% by weight to 10% by weight) is preferable.

The monomer (V) may be a monomer copolymerizable with one or more monomers selected from the group consisting of the monomers (I), (II), (III) and (IV). There is no particular limitation. The monomer (V) does not contain the monomer (I), the monomer (II), the monomer (III) and the monomer (IV).

Examples of the monomer (V) include the following, and one or more of these can be used;

General formula (V-1):

で示されるジアリルビスフェノール類、例えば４，４’−ジヒドロキシジフェニルプロパン、４，４’−ジヒドロキシジフェニルメタン、４，４’−ジヒドロキシジフェニルスルホンの３および３’位アリル置換物；

3 and 3'-position allyl substitutions of diallyl bisphenols represented by, for example, 4,4'-dihydroxydiphenylpropane, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenylsulfone;

General formula (V-2):

で示されるモノアリルビスフェノール類、例えば４，４’−ジヒドロキシジフェニルプロパン、４，４’−ジヒドロキシジフェニルメタン、４，４’−ジヒドロキシジフェニルスルホンの３位アリル置換物；

Monoallyl bisphenols represented by, for example, 3-position allyl substitutions of 4,4'-dihydroxydiphenylpropane, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenylsulfone;

General formula (V-3):

で示されるアリルフェノール；

Allylphenol indicated by;

Half-esters and diesters of unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, fumaric acid, itaconic acid, and citraconic acid and alcohols having 1 to 30 carbon atoms;
Half-amides and diamides of the unsaturated dicarboxylic acids and amines having 1 to 30 carbon atoms;
Half esters and diesters of alkyl (poly) alkylene glycols obtained by adding 1 to 500 mol of alkylene oxides having 2 to 18 carbon atoms to the alcohols or amines and unsaturated dicarboxylic acids;
Half-esters and diesters of the unsaturated dicarboxylic acids and glycols having 2 to 18 carbon atoms or polyalkylene glycols having 2 to 500 moles of these glycols;
Half-amides of maleamic acid and glycols with 2 to 18 carbon atoms or polyalkylene glycols with 2 to 500 moles of these glycols;

(Poly) alkylene glycols such as triethylene glycol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, (poly) ethylene glycol (poly) propylene glycol di (meth) acrylate Di (meth) acrylates;
Polyfunctional (meth) acrylates such as hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and trimethylolpropane di (meth) acrylate;
(Poly) alkylene glycol dimalates such as triethylene glycol dimalate and polyethylene glycol dimalate;
Vinyl Sulfonate, (Meta) Allyl Sulfonate, 2- (Meta) Acryloxyethyl Sulfonate, 3- (Meta) Acryloxypropyl Sulfonate, 3- (Meta) Acryloxy-2-Hydroxypropyl Sulfonate, 3- (Meta) Acryloxy-2 -Hydroxypropyl sulfophenyl ether, 3- (meth) acryloxy-2-hydroxypropyloxysulfobenzoate, 4- (meth) acryloxybutyl sulfonate, (meth) acrylamide methyl sulfonic acid, (meth) acrylamide ethyl sulfonic acid, 2- Unsaturated sulfonic acids such as methylpropanesulfonic acid (meth) acrylamide and styrenesulfonic acid, and their monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts;
Amides of unsaturated monocarboxylic acids such as methyl (meth) acrylamide and amines with 1 to 30 carbon atoms;
Vinyl aromatics such as styrene, α-methylstyrene, vinyltoluene, p-methylstyrene;
Alkanediol mono (meth) acrylates such as 1,4-butanediol mono (meth) acrylate, 1,5-pentanediol mono (meth) acrylate, and 1,6-hexanediol mono (meth) acrylate;
Dienes such as butadiene, isoprene, 2-methyl-1,3-butadiene, 2-chlor-1,3-butadiene;

Unsaturated amides such as (meth) acrylamide, (meth) acrylic alkylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide;
(Meta) Unsaturated cyanes such as acrylonitrile and α-chloroacrylonitrile;
Unsaturated esters such as vinyl acetate and vinyl propionate;
Unsaturation of (meth) aminoethyl acrylate, methylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dibutylaminoethyl (meth) acrylate, vinylpyridine, etc. Amines;
Divinyl aromatics such as divinylbenzene; cyanurates such as triallyl cyanurate;
Allyls such as (meth) allyl alcohol and glycidyl (meth) allyl ether;
Vinyl ethers or allyl ethers such as methoxypolyethylene glycol monovinyl ether, polyethylene glycol monovinyl ether, methoxypolyethylene glycol mono (meth) allyl ether, polyethylene glycol mono (meth) allyl ether;
Polydimethylsiloxane propylaminomale amidoic acid, polydimethylsiloxane aminopropylene aminomale amidoic acid, polydimethylsiloxane-bis- (propylaminomale amidoic acid), polydimethylsiloxane-bis- (dipropylene aminomale amidoic acid), polydimethyl Siloxane- (1-propyl-3-acrylate), polydimethylsiloxane- (1-propyl-3-methacrylate), polydimethylsiloxane-bis- (1-propyl-3-acrylate), polydimethylsiloxane-bis- (1) A siloxane derivative such as −propyl-3-methacrylate).

The monomer (V) may be of one type or a combination of two or more types.

The monomer (V) preferably contains the 3 and 3'-allyl substitutions of 4,4'-dihydroxydiphenyl sulfone, and is the 3 and 3'-allyl substitution of 4,4'-dihydroxydiphenyl sulfone. Is preferable.

Component (A): In order to obtain a polycarboxylic acid-based copolymer or a salt (A) thereof, a monomer (I), a monomer (II), a monomer (III), and a single amount are required. Monomers other than the body (IV) and the monomer (V) may be used.

In the present invention, the component (A): polycarboxylic acid-based copolymer or a salt (A) thereof can be produced by copolymerizing each predetermined monomer by a known method. Examples of the method include polymerization methods such as polymerization in a solvent and bulk polymerization.

Solvents used in polymerization in solvents include, for example, water; lower alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol; aromatic hydrocarbons such as benzene, toluene, xylene; fats such as cyclohexane and n-hexane. Group hydrocarbons; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone. From the viewpoint of solubility of the raw material monomer and the obtained copolymer, it is preferable to use one or more selected from the group consisting of water and lower alcohols, and it is more preferable to use water among them.

When copolymerizing in a solvent, each monomer and the polymerization initiator may be continuously added dropwise to the reaction vessel, or a mixture of the monomers and the polymerization initiator may be continuously added dropwise to the reaction vessel. May be good. Alternatively, the solvent may be charged into the reaction vessel, and the mixture of the monomer and the solvent and the polymerization initiator solution may be continuously added dropwise to the reaction vessel, or a part or all of the monomer may be charged into the reaction vessel for polymerization. The initiator may be continuously added dropwise.

When copolymerizing in a solvent, it is preferable that each monomer is mixed in a container different from the reaction vessel, which is installed in front of the vessel in which the reaction is carried out in advance, and then continuously added dropwise to the reaction vessel.

Component (A): The polycarboxylic acid-based copolymer or a salt thereof (A) may be added to the cement admixture as it is containing the reaction solvent or the like after the copolymerization reaction is completed, or some further. It may be added in a treated state. Treatments include, for example, removal of reaction solvent, concentration adjustment by concentration or dilution, purification, pH adjustment and the like. After completion of the reaction, it is preferable to adjust the concentration and / or pH in a container installed after the reaction vessel. The method for adjusting the concentration is not particularly limited, but for example, it may be concentrated or diluted with water. The pH adjustment will be described later.

The polymerization initiators that can be used for copolymerization are persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate when copolymerizing in an aqueous solvent; t-butyl hydroperoxide and hydrogen peroxide. Water-soluble organic peroxides such as. At this time, an accelerator such as sodium bisulfite or moor salt or a reducing agent such as ascorbic acid or monosaccharide can be used in combination. Further, when the copolymerization is carried out in a solvent such as a lower alcohol, an aromatic hydrocarbon, an aliphatic hydrocarbon, an ester or a ketone, for example, a peroxide such as a benzoyl peroxide or a lauryl peroxide; a cumene peroxide. Hydrocarbons such as; aromatic azo compounds such as azobisisobutyronitrile can be used as the polymerization initiator. At this time, an accelerator such as an amine compound can also be used in combination. Further, when copolymerization is carried out in a water-lower alcohol mixed solvent, the above-mentioned polymerization initiator or combination of the polymerization initiator and the accelerator can be appropriately selected and used. The polymerization temperature varies depending on the polymerization conditions such as the solvent used and the type of the polymerization initiator, but is usually in the range of 50 to 120 ° C.

Further, in the copolymerization, the molecular weight can be adjusted by using a chain transfer agent as needed. Chain transfer agents used include, for example, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thioapple acid, octyl thioglycolate, and 2-. Known thiol compounds such as mercaptoethanesulfonic acid: phosphite, hypophosphite, and salts thereof (sodium bisulfite, potassium hypophosphate, etc.), sulfite, hydrogen sulfite, dithionic acid, meta Lower oxides of bisulfite and its salts (sodium bisulfite, potassium sulfite, sodium bisulfite, potassium bisulfite, sodium bisulfite, potassium bisulfite, sodium metabisulfite, potassium metabisulfite, etc.) and their salts. Salt; etc. These may be used alone or in combination of two or more. Further, in order to adjust the molecular weight of the polycarboxylic acid-based copolymer or its salt (A), it is also effective to use a monomer (V) having a higher chain transfer property as the monomer for obtaining each. Is. Examples of the monomer (V) having high chain transferability include (meth) allylsulfonic acid (salt) -based monomers. The blending ratio of the monomer (V) is usually 20% by weight or less, preferably 10% by weight or less in the polycarboxylic acid-based copolymer or the salt (A) thereof. Regarding (A), the above-mentioned compounding ratio is the compounding ratio of the monomer (I) + the compounding ratio of the monomer (II) + the compounding ratio of the monomer (III) + the compounding of the monomer (IV). Ratio + compounding ratio of monomer (V) = 100% by weight.

When copolymerizing in an aqueous solvent, the pH at the time of polymerization is usually strongly acidic due to the influence of a monomer having an unsaturated bond, but this may be adjusted to an appropriate pH. If it is necessary to adjust the pH during polymerization, adjust the pH using acidic substances such as phosphoric acid, sulfuric acid, nitric acid, alkyl phosphoric acid, alkyl sulfuric acid, alkyl sulfonic acid, and (alkyl) benzene sulfonic acid. Can be done. Among these acidic substances, it is preferable to use phosphoric acid because it has a pH buffering action. However, in order to eliminate the instability of the ester bond of the ester-based monomer, it is preferable to carry out the polymerization at pH 2 to 7. The alkaline substance that can be used for adjusting the pH is not particularly limited, but alkaline substances such as NaOH and Ba (OH) ₂ are generally used. The pH adjustment may be performed on the monomer before the polymerization or on the copolymer solution after the polymerization. Further, these may be polymerized by adding a part of alkaline substances before polymerization, and then the pH of the copolymer may be further adjusted.

Component (A): The weight average molecular weight of the polycarboxylic acid-based copolymer or its salt (A) is preferably 5,000 or more, more preferably 6,000 or more, and 6,500 or more. It is more preferably present, and particularly preferably 9,000 or more. As a result, the cement dispersibility of the cement admixture is sufficiently exhibited, an excellent water reduction rate can be obtained, the fluidity or workability is improved, and the desired effect as the cement admixture can be sufficiently exhibited. .. The upper limit of the weight average molecular weight is preferably 60,000 or less, more preferably 50,000 or less, and even more preferably 30,000 or less. As a result, the agglutination action of cement particles is suppressed, and workability can be improved. The weight average molecular weight is preferably 5,000 to 60,000, more preferably 6,000 to 50,000, and even more preferably 9,000 to 30,000.

Component (A): The molecular weight distribution (Mw / Mn) of the polycarboxylic acid-based copolymer or its salt (A) is preferably 1.2 or more, and more preferably 1.25 or more. The upper limit is preferably 3.0 or less, and more preferably 2.50 or less. The molecular weight distribution is preferably in the range of 1.2 to 3.0.

The weight average molecular weight in the present invention can be measured by a known method of converting into polyethylene glycol by gel permeation chromatography (GPB).

The GPB measurement conditions are not particularly limited, but the following conditions can be mentioned as examples. The weight average molecular weight in the latter example is a value measured under this condition.
Measuring device; Column used by Tosoh; ShoCex Volume OH-pak SB-806HQ, SB-804HQ, SB-802.5HQ
Eluent; 0.05 mM sodium nitrate / acetonitrile 8/2 (v / v)
Standard substance: Polyethylene glycol (manufactured by Tosoh, manufactured by GL Science)
Detector; differential refractometer (manufactured by Tosoh)
Calibration curve; polyethylene glycol standard

Component (A): The polycarboxylic acid-based copolymer or a salt (A) thereof may be one kind or a combination of two or more kinds different from each other.

Component (A) in the cement admixture for post-addition of the present invention: The content of the polycarboxylic acid-based copolymer or its salt (A) is not limited, but with respect to the total weight of the cement admixture for post-addition. It is preferably 10% by weight to 100% by weight.

The component (A) of the present invention: a polycarboxylic acid-based copolymer or a salt thereof (A) can also be used as a cement admixture for initial addition as a cement admixture (D), but the initial water reduction / dispersion Considering the properties and compatibility with the cement composition for post-addition of the present invention, it is preferable to use the component (B) and / or the component (C) described later as the cement admixture (D).

<Ingredient (B)>
The component (B) of the present invention is a monomer (I) represented by the general formula (1) and an unsaturated carboxylic acid-based monomer (IV), or a monomer (I), a monomer. A polycarboxylic acid-based copolymer or a salt thereof obtained by copolymerizing (IV) and the monomer (I) and another monomer (VI) copolymerizable with the monomer (IV). B).
Component (B): The polycarboxylic acid-based copolymer or its salt (B) is different from the polycarboxylic acid-based copolymer or its salts (A) and (C) in that the monomer (II) is not copolymerized. Can be distinguished. Examples and preferred examples of each of the monomer (I) and the monomer (IV) are those of the monomers (I) and (IV) described in the polycarboxylic acid-based copolymer or the salt (A) thereof. Same as each example and preferred example.

The monomer (VI) may be copolymerizable with the monomers (I) and (IV), may be copolymerized with the monomer (II), or the monomers (I) to (IV). It may be copolymerizable with a monomer other than). Examples and preferred examples of the monomer (VI) are the same as those of the monomer (V) described in the polycarboxylic acid-based copolymer or its salt (A) and preferred examples. Examples and preferred examples of the method for producing the polycarboxylic acid-based copolymer or the salt (B) thereof are the same as the examples and preferred examples of the method for producing the polycarboxylic acid-based copolymer or the salt (A) thereof.

Component (B): The compounding ratio of each monomer when obtaining the polycarboxylic acid-based copolymer or the salt (B) thereof is as follows. The blending ratio of the monomer (I) is preferably 40% by weight to 97% by weight, more preferably 50% by weight to 97% by weight, and further preferably 60% by weight to 97% by weight. The blending ratio of the monomer (IV) is preferably 1% by weight to 60% by weight, more preferably 1% by weight to 50% by weight, and further preferably 1% by weight to 40% by weight. The compounding ratio of the monomer (VI) is preferably 0% by weight to 50% by weight, more preferably 0% by weight to 40% by weight, and further preferably 0% by weight to 30% by weight. However, the compounding ratio of the monomer (I) + the compounding ratio of the monomer (IV) + the compounding ratio of the monomer (VI) = 100% by weight.

In the component (B): polycarboxylic acid-based copolymer or salt (B) thereof, the ratio of the blending amount of the monomer (IV) to the blending amount of the monomer (I) is preferably 1% by weight to 70% by weight. It is by weight%, more preferably 5% by weight to 70% by weight, still more preferably 5% by weight to 60% by weight. The ratio of the blending amount of the monomer (VI) to the blending amount of the monomer (I) is preferably 0% by weight to 50% by weight, more preferably 0% by weight to 40% by weight, and further preferably. Is 0% by weight to 30% by weight.

Component (B): The weight average molecular weight of the polycarboxylic acid-based copolymer or its salt (B) is preferably 5,000 to 60,000, more preferably 6,000 to 50,000. ..

Component (B): The molecular weight distribution (Mw / Mn) of the polycarboxylic acid-based copolymer or its salt (B) is preferably in the range of 1.2 to 3.0, preferably 1.25 to 2.5. More preferably.

Component (B): The polycarboxylic acid-based copolymer or its salt (B) may be one kind or a combination of two or more kinds different from each other.

When the component (B): polycarboxylic acid-based copolymer or salt (B) thereof is used as the cement admixture (D) of the present invention, it is contained in the cement composition for post-addition in the cement composition ( The component (B) component: the polycarboxylic acid-based copolymer or its salt (B) is 1% by weight to 500% by weight with respect to the component (A) component: the polycarboxylic acid-based copolymer or its salt (A). It is preferably 1% by weight to 300% by weight, more preferably 50% by weight to 300% by weight.

<Component (C)>
The component (C) of the present invention is a monomer (II) represented by the general formula (2) and an unsaturated carboxylic acid-based monomer (IV), or a monomer (II) or a monomer. With a polycarboxylic acid-based copolymer obtained by copolymerizing (IV) and another monomer (VII) copolymerizable with the monomer (II) and (IV) or a salt (C) thereof. is there.
Component (C): Polycarboxylic acid-based copolymer or salt thereof (C) does not copolymerize monomer (I). Component (A) Component: Polycarboxylic acid-based copolymer or salt thereof (A) and Component (B): Different from the polycarboxylic acid-based copolymer or its salt (B). Component (C): In the polycarboxylic acid-based copolymer or a salt (C) thereof, examples and preferred examples of the monomer (II) and the monomer (IV) are: Component (A): Polycarboxylic acid. It is the same as each example and preferable example of the monomer (II) and (IV) described in the system copolymer or the salt (A) thereof.

The monomer (VII) may be copolymerizable with the monomers (II) and (IV), may be copolymerized with the monomer (I), or the monomers (I) to (IV). It may be copolymerizable with a monomer other than). Examples and preferred examples of the monomer (VII) are the same as those of the monomer (V) described in the polycarboxylic acid-based copolymer or the salt (A) thereof and the preferred examples. Examples and preferred examples of the method for producing the polycarboxylic acid-based copolymer or the salt (C) thereof are the same as the examples and preferred examples of the polycarboxylic acid-based copolymer or the salt (A) thereof.

Component (C): The compounding ratio of each monomer when obtaining the polycarboxylic acid-based copolymer or the salt (C) thereof is as follows. The blending ratio of the monomer (II) is preferably 40% by weight to 97% by weight, more preferably 50% by weight to 97% by weight, and further preferably 60% by weight to 97% by weight. The blending ratio of the monomer (IV) is preferably 1% by weight to 60% by weight, more preferably 1% by weight to 50% by weight, and further preferably 1% by weight to 40% by weight. The blending ratio of the monomer (VII) is preferably 0% by weight to 50% by weight, more preferably 0% by weight to 40% by weight, and further preferably 0% by weight to 30% by weight. However, the compounding ratio of the monomer (II) + the compounding ratio of the monomer (IV) + the compounding ratio of the monomer (VII) = 100% by weight.

In the component (C): polycarboxylic acid-based copolymer or salt (C) thereof, the ratio of the blending amount of the monomer (IV) to the blending amount of the monomer (II) is preferably 1% by weight to 70% by weight. It is by weight%, more preferably 5% by weight to 70% by weight, still more preferably 5% by weight to 60% by weight. The ratio of the blending amount of the monomer (VII) to the blending amount of the monomer (II) is preferably 0% by weight to 50% by weight, more preferably 0% by weight to 40% by weight, and further preferably. Is 0% by weight to 30% by weight.

Component (C): The weight average molecular weight of the polycarboxylic acid-based copolymer or its salt (C) is preferably 5,000 to 60,000, more preferably 6,000 to 50,000. ..

Component (C): The molecular weight distribution (Mw / Mn) of the polycarboxylic acid-based copolymer or its salt (C) is preferably in the range of 1.2 to 3.0, preferably 1.25 to 2.5. More preferably.

Component (C): The polycarboxylic acid-based copolymer or its salt (C) may be one kind or a combination of two or more kinds different from each other.

When the component (C): polycarboxylic acid-based copolymer or salt (C) thereof is used as the cement admixture (D) of the present invention, the component contained in the post-addition cement admixture in the cement composition. (A): The component (C): the polycarboxylic acid-based copolymer or its salt (C) is 1% by weight to 500% by weight with respect to the polycarboxylic acid-based copolymer or its salt (A). Is more preferable, 1% by weight to 300% by weight is more preferable, and 50% by weight to 300% by weight is more preferable.

Each of the monomers (I) to (VII) constituting the components (A), (B) and (C) of the present invention is independent and may be the same or separate.

In the cement admixture for post-addition of the present invention, the content form of the component (A) is not limited, and the component (A) may be contained as it is, or a solution or dispersion in which the component (A) is dissolved in a solvent. It may be blended as a dispersed dispersion or a suspended suspension. The dispersion liquid may also contain a commercially available dispersant. Further, if necessary, the component (B) and the component (C) can be used in combination with the component (A) as long as the effects of the present invention are not impaired, and can be used as a cement admixture for post-addition. (When the cement admixture for post-addition of the present invention contains the component (B) and / or the component (C), the solution, dispersion or suspension of the components (A) and (B) and the component (B) A solution in which the component (C) is dissolved in a solvent, a dispersed solution, and a suspended suspension are separately prepared, and these are mixed to prepare a cement admixture for post-addition. You may.

The cement admixture for post-addition of the present invention can be used in the form of an aqueous solution or in the form of being dried and powdered.

The cement admixture for post-addition of the present invention can be used by post-adding to a cement composition (base cement) such as cement paste containing a hydraulic material such as cement, mortar, concrete, and plaster.

The cement composition of the present invention may contain a cement admixture for post-addition, and the hydraulic material to be combined is not particularly limited. Examples of the hydraulic material include cement, gypsum (hemihydrate gypsum, dihydrate gypsum, etc.), and dolomite. The most common hydraulic material is cement.

The cement is not particularly limited. For example, Portoland cement (normal, fast-strength, super-fast-strength, moderate heat, sulfate-resistant and each low-alkali form), various mixed cements (blast furnace cement, silica cement, fly ash cement), white Portorand cement, alumina cement, Ultra-fast-hardening cement (1 clinker fast-hardening cement, 2 clinker fast-hardening cement, magnesium phosphate cement), grout cement, oil well cement, low heat-generating cement (low-heat-generating blast furnace cement, fly ash mixed low-heat-generating blast furnace cement, belite High-content cement), ultra-high-strength cement, cement-based solidifying material, eco-cement (cement manufactured from one or more of municipal waste incineration ash and sewage sludge incineration ash) and the like. Fine powder such as blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica fume, silica powder, limestone powder, gypsum and the like may be added to the cement.

In addition, the cement composition may contain aggregate. The aggregate may be either a fine aggregate or a coarse aggregate. Aggregates include, for example, sand, gravel, crushed stone; granulated slag; recycled aggregate, etc .; silica stone, clay, zirconite, high alumina, silicon carbide, graphite, chromium, chromog, magnesia. Fire-resistant aggregates such as.

The mixing ratio of the cement admixture for post-addition in the cement composition is not particularly limited. For example, when the cement composition is mortar or concrete, the addition amount (blending amount) of the polycarboxylic acid-based copolymer or its salt (A) contained in the cement admixture for post-addition is the total amount of the cement. It is usually 0.01 to 5.0% by weight, preferably 0.02 to 2.0% by weight, and more preferably 0.05 to 1.0% by weight based on the weight. With this addition amount, the obtained cement composition has various preferable effects such as reduction of unit water amount, increase of strength, and improvement of durability. If the above compounding ratio is less than 0.01% by weight, the obtained cement composition may not have sufficient performance, and conversely, even if a large amount exceeding 5.0% by weight is used, the effect is substantially effective. It may reach a plateau and be disadvantageous in terms of economy.

The above cement composition is effective as concrete such as ready mixed concrete, concrete for secondary concrete products (precast concrete), concrete for centrifugal molding, concrete for vibration compaction, steam curing concrete, and sprayed concrete. .. In addition, medium-fluidity concrete (concrete with a slump value in the range of 22 to 25 cm), high-fluidity concrete (concrete with a slump value of 25 cm or more and a slump flow value in the range of 50 to 70 cm), self-filling concrete, self-leveling material. It is also effective as mortar or concrete, which requires high fluidity such as.

The cement admixture for post-addition of the present invention is still another cement dispersant, water-soluble polymer, polymer emulsion, air entraining agent, cement wetting agent, swelling agent, waterproofing agent, retarder, thickener, coagulant. It can also be used in combination with known concrete additives such as drying shrinkage reducing agents, strength enhancers, curing accelerators, defoaming agents, AE agents, and other surfactants. These may be used alone or two or more kinds may be used.

Examples of other cement dispersants include sulfonic acid-based dispersants (S) such as naphthalene sulfonic acid formaldehyde condensate, melamine sulfonic acid formaldehyde condensate, and lignin sulfonate. The content of the sulfonic acid-based dispersant (S) is 0.01% by weight to 50% by weight with respect to the total amount of the component (A), the component (B), and the component (C) of the present invention. Is preferable. In the present specification, when the term "total amount of component (A), component (B), and component (C)" is used, all of the components (A), (B), and (C) are the present invention. It does not only mean the total amount when it is contained in the cement admixture of the present invention, but also when either the component (B) or the component (C) is not contained in the cement admixture for post-addition of the present invention. It also means the total amount when the weight of the components not included is calculated as 0.

Examples of the water-soluble polymer (P) include polyalkylene glycol and cellulosic compounds. Specific examples thereof include polyethylene glycol, polypropylene glycol, polyethylene polypropylene glycol, polyethylene polybutylene glycol, hydroxyethyl cellulose, hydroxymethyl cellulose and methyl cellulose. , Hydroxypropyl methylcellulose and the like. The content of the water-soluble polymer (P) may be 0.01% by weight to 50% by weight with respect to the total amount of the component (A), the component (B), and the component (C) of the present invention. preferable.

Examples of the delaying agent include oxycarboxylic acids such as gluconic acid (salt) and citric acid (salt), sugars such as glucose, and sugar alcohols (G) such as sorbitol. The content of the sugar alcohol (G) is preferably 0.01% by weight to 50% by weight with respect to the total amount of the component (A), the component (B), and the component (C) of the present invention. ..

Examples of the curing accelerator include soluble calcium salts such as calcium chloride, calcium nitrite and calcium nitrate, chlorides such as iron chloride and magnesium chloride, and formates (K) such as thiosulfate, formic acid and calcium formate. Can be mentioned. The content of the curing accelerator (K) is preferably 0.01% by weight to 50% by weight with respect to the total amount of the component (A), the component (B), and the component (C) of the present invention. ..

Examples of the thickener include hydroxypropyl methylcellulose, methylcellulose, carboxymethylcellulose, known cellulose nanofibers, and known cellulose nanocrystals (Z). The content of the thickener (Z) is preferably 0.01% by weight to 50% by weight with respect to the total amount of the component (A), the component (B), and the component (C) of the present invention. ..

The present invention will be described in more detail with reference to Examples below, but the present invention is not limited thereto. In the example, unless otherwise specified,% indicates a weight% and a part indicates a weight part.

<Ingredient (A)>
<Manufacturing example 1>
148 parts of water and polyethylene polypropylene glycol monoallyl ether (average number of moles of ethylene oxide added 39, average mole of propylene oxide added) in a glass reaction vessel equipped with a thermometer, agitator, reflux device, nitrogen introduction tube and dropping device. (3, Random addition of ethylene oxide and propylene oxide) 94 parts were charged, and the temperature was raised to 80 ° C. in the reaction vessel under stirring. After that, 35 parts of methacrylic acid, 5 parts of acrylic acid (monomer / dimer = 99% by weight / 1% by weight), 63 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide 13), 60 parts of 2-hydroxyethyl acrylate. , 8 parts of 3-mercaptopropionic acid and 165 parts of water were mixed, and a mixed solution of 3 parts of ammonium persulfate and 47 parts of water was continuously added dropwise to a reaction vessel kept at 80 ° C. for 2 hours each. Further, an aqueous solution of the copolymer was obtained by reacting for 1 hour while keeping the temperature at 100 ° C. The weight ratio of the monomers in the copolymer in the liquid was monomer I: II: III: IV: V = 37: 25: 23: 15: 0. The copolymer in the liquid was a copolymer (A-1) (weight average molecular weight 10,000, Mw / Mn1.5).

<Manufacturing example 2>
105 parts of water, 3 parts of a mixture of 2-hydroxypropyl acrylate and 2-hydroxy-1-methylethyl acrylate, and polyethylene polypropylene in a glass reaction vessel equipped with a thermometer, agitator, reflux device, nitrogen introduction tube and dropping device. 26 parts of glycol monoallyl ether (average number of moles of ethylene oxide added 33, average number of moles of propylene oxide 2 added, 2 mol of propylene oxide added to allyl unit and then 33 mol of ethylene oxide added) was charged and reacted under stirring. The container was replaced with ethylene, and the temperature was raised to 100 ° C. under a nitrogen atmosphere. After that, 9 parts of methacrylic acid, 1 part of acrylic acid (monomer / dimer = 99% by weight / 1% by weight), 53 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide 25), 2-hydroxypropyl acrylate and 2 A monomer aqueous solution in which 84 parts of a mixture of −hydroxy-1-methylethylacrylate, 3 parts of 3-mercaptopropionic acid, and 51 parts of water was mixed, and a mixed solution of 1 part of ammonium persulfate and 47 parts of water were prepared for 3 hours each. It was continuously added dropwise to a reaction vessel kept at 100 ° C. Further, an aqueous solution of the copolymer was obtained by reacting for 1 hour while keeping the temperature at 100 ° C. The weight ratio of the monomers in the copolymer in the liquid was monomer I: II: III: IV: V = 15: 30: 49: 6: 0. The copolymer in the liquid was a copolymer (A-2) (weight average molecular weight 19,000, Mw / Mn1.4).

<Manufacturing example 3>
137 parts of water and 52 parts of polyethylene glycol monoallyl ether (average number of added moles of ethylene oxide 10) were charged into a glass reaction vessel equipped with a thermometer, agitator, a reflux device, a nitrogen introduction tube and a dropping device, and the mixture was stirred. The reaction vessel was replaced with nitrogen and the temperature was raised to 80 ° C. in a nitrogen atmosphere. After that, 5 parts of methacrylic acid, 5 parts of acrylic acid (monomer / dimer = 99% by weight / 1% by weight), 87 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide 17), 20 parts of 2-hydroxyethyl acrylate. , 20 parts of methyl methacrylate, 7 parts of 3-mercaptopropionic acid, and 120 parts of water were mixed, and a mixed solution of 2 parts of ammonium persulfate and 48 parts of water was kept at 80 ° C. for 2 hours each. Was continuously dropped into the water. Further, an aqueous solution of the copolymer was obtained by reacting for 1 hour while keeping the temperature at 100 ° C. The weight ratio of the monomers in the copolymer in the liquid was monomer I: II: III: IV: V = 28: 46: 21: 5: 0. The copolymer in the liquid was a copolymer (A-3) (weight average molecular weight 20,500, Mw / Mn1.5).

<Manufacturing example 4>
155 parts of water in a glass reaction vessel equipped with a thermometer, stirrer, reflux device, nitrogen introduction tube and dropping device, and ethylene oxide propylene oxide adduct of 3-methyl-3-buten-1-ol (ethylene oxide) An average number of moles of 45 was added, an average number of moles of propylene oxide was 3, and 70 parts of ethylene oxide and propylene oxide were randomly added.) The reaction vessel was replaced with nitrogen under stirring, and the temperature was raised to 80 ° C. under a nitrogen atmosphere. After that, 15 parts of methacrylic acid, 5 parts of acrylic acid (monomer / dimer = 99% by weight / 1% by weight), 33 parts of methoxypolyethylene glycol methacrylate (average number of moles of ethylene oxide added 13), 87 parts of 2-hydroxyethyl acrylate. , 3-Part of mercaptopropionic acid and 119 parts of water were mixed, and a mixed solution of 3 parts of ammonium persulfate and 47 parts of water was continuously added dropwise to a reaction vessel kept at 80 ° C. for 2 hours each. Further, an aqueous solution of the copolymer was obtained by reacting for 1 hour while keeping the temperature at 100 ° C. The weight ratio of the monomers in the copolymer in the liquid was monomer I: II: III: IV: V = 33: 16: 41: 10: 0. The copolymer in the liquid was a copolymer (A-4) (weight average molecular weight 24,500, Mw / Mn1.5).

<Manufacturing example 5>
100 parts of water and an ethylene adduct adduct of 3-methyl-3-buten-1-ol (average addition of ethylene oxide) in a glass reaction vessel equipped with a thermometer, agitator, recirculation device, nitrogen introduction tube and dropping device. The number of moles 67) 143 parts was charged, the reaction vessel was replaced with ethylene under stirring, and the temperature was raised to 60 ° C. under a nitrogen atmosphere. After that, 15 parts of methacrylic acid, 15 parts of acrylic acid (monomer / dimer = 99% by weight / 1% by weight), 34 parts of methoxypolyethylene glycol methacrylate (average number of moles of ethylene oxide added 25), 42 parts of 2-hydroxypropyl acrylate. , 3-Mercaptopropionic acid 6 parts, ascorbic acid 5 parts, water 138 parts mixed monomer aqueous solution and a mixed solution of hydrogen peroxide 4 parts and water 46 parts each were held at 80 ° C. for 2 hours. It was continuously added dropwise to the container. Further, an aqueous solution of the copolymer was obtained by reacting for 1 hour while keeping the temperature at 60 ° C. The weight ratio of the monomers in the copolymer in the liquid was monomer I: II: III: IV: V = 57: 14: 17: 12: 0. The copolymer in the liquid was a copolymer (A-5) (weight average molecular weight 20,200, Mw / Mn1.6).

<Manufacturing example 6>
195 parts of water, 21 parts of 2-hydroxyethyl acrylate, polyethylene polypropylene glycol monoallyl ether (average number of moles of ethylene oxide added 10,) in a glass reaction vessel equipped with a thermometer, agitator, a reflux device, a nitrogen introduction tube and a dropping device. The average number of moles of propylene oxide added is 1, 10 mol of ethylene oxide is added to the allyl unit, and then the same volume of propylene oxide is added) 50 parts, and the 3 and 3'positions of 4,4'-dihydroxydiphenylsulfone are allyl-substituted. 3 parts of the compound was charged, the reaction vessel was replaced with ethylene under stirring, and the temperature was raised to 80 ° C. under a nitrogen atmosphere. After that, 40 parts of methacrylic acid, 5 parts of acrylic acid (monomer / dimer = 99% by weight / 1% by weight), 100 parts of methoxypolyethylene glycol methacrylate (average number of moles of ethylene oxide added 25), 60 parts of 2-hydroxyethyl acrylate. , 8-part 3-mercaptopropionic acid and 150 parts of water were mixed, and a mixed solution of 3 parts of ammonium persulfate and 47 parts of water was continuously added dropwise to a reaction vessel kept at 80 ° C. for 2 hours each. Further, an aqueous solution of the copolymer was obtained by reacting for 1 hour while keeping the temperature at 100 ° C. The weight ratio of the monomers in the copolymer in the liquid was monomer I: II: III: IV: V = 18: 36: 29: 16: 1. The copolymer in the liquid was a copolymer (A-6) (weight average molecular weight 11,600, Mw / Mn1.5).

<Manufacturing example 7>
A glass reaction vessel equipped with a thermometer, agitator, a reflux device, a nitrogen introduction tube and a dropping device was charged with 195 parts of water and 55 parts of polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added 10), and reacted under stirring. The container was replaced with nitrogen, and the temperature was raised to 100 ° C. under a nitrogen atmosphere. After that, 12 parts of methacrylic acid, 4 parts of acrylic acid (monomer / dimer = 99% by weight / 1% by weight), 57 parts of methoxypolyethylene glycol methacrylate (average number of moles of ethylene oxide added), 57 parts of methoxypolyethylene glycol methacrylate (ethylene). The average number of moles of oxide 13) 35 parts, 8 parts of 3-mercaptopropionic acid, and 150 parts of water were mixed to form a monomer aqueous solution, and a mixed solution of 3 parts of ammonium persulfate and 47 parts of water was mixed at 100 ° C. for 2 hours each. It was continuously added dropwise to the reaction vessel held in. Further, an aqueous solution of the copolymer was obtained by reacting for 1 hour while keeping the temperature at 100 ° C. The weight ratio of the monomers in the copolymer in the liquid was monomer I: II: IV = 34: 56:10. The copolymer in the liquid was a copolymer (A-7) (weight average molecular weight 11,600, Mw / Mn1.5).

<Components (B) and (C)>
<Manufacturing example 8>
148 parts of water and 347 parts of polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added 40) were charged into a glass reaction vessel equipped with a thermometer, agitator, a reflux device, a nitrogen introduction tube and a dropping device, and the mixture was stirred. The reaction vessel was replaced with nitrogen and the temperature was raised to 80 ° C. in a nitrogen atmosphere. Then, 90 parts of acrylic acid (monomer / dimer = 99% by weight / 1% by weight), 1 part of 30% NaOH aqueous solution, and 288 parts of water were mixed to form a monomer aqueous solution, and 7 parts of ammonium persulfate and 113 parts of water were mixed. Was continuously added dropwise to the reaction vessel kept at 80 ° C. for 2 hours each. Further, an aqueous solution of the copolymer was obtained by reacting for 1 hour while keeping the temperature at 100 ° C. The weight ratio of the monomers in the copolymer in the liquid was monomer I: IV: VI = 79: 21: 0. The copolymer in the liquid was a copolymer (B-1) (weight average molecular weight 16,000, Mw / Mn 1.7).

<Manufacturing example 9>
501 parts of water, ethylene oxide adduct of 3-methyl-3-butene-1-ol (average number of moles of ethylene oxide adduct) in a glass reaction vessel equipped with a thermometer, agitator, reflux device, nitrogen introduction tube and dropping device. 30) 500 parts and 2 parts of the compound in which the 3 and 3'positions of 4,4'-dihydroxydiphenylsulfone were allyl-substituted were charged, the reaction vessel was replaced with nitrogen under stirring, and the temperature was raised to 80 ° C. under a nitrogen atmosphere. did. Then, an aqueous monomer solution prepared by mixing 135 parts of acrylic acid (monomer / dimer = 99% by weight / 1% by weight) and 501 parts of water and a mixed solution of 12 parts of ammonium persulfate and 188 parts of water were added to each of 80 parts in 1 hour. It was continuously added dropwise to a reaction vessel kept at ° C. Further, an aqueous solution of the copolymer was obtained by reacting for 1 hour while keeping the temperature at 100 ° C. The weight ratio of the monomers in the copolymer in the liquid was monomer I: IV: VI = 78: 21: 1. The copolymer in the liquid was a copolymer (B-2) (weight average molecular weight 20,200, Mw / Mn1.7).

<Manufacturing example 10>
1052 parts of water was charged in a glass reaction vessel equipped with a thermometer, a stirrer, a reflux device, a nitrogen introduction tube and a dropping device, the reaction vessel was replaced with nitrogen under stirring, and the temperature was raised to 80 ° C. under a nitrogen atmosphere. Then, 323 parts of methoxypolyethylene glycol methacrylate (average number of moles of ethylene oxide added: 13), 2 parts of the compound in which the 3 and 3'positions of 4,4'-dihydroxydiphenyl sulfone were allyl-substituted, 39 parts of methacrylic acid, and 357 parts of water. A mixed solution of 7 parts of sodium persulfate and 113 parts of water was continuously added dropwise to a reaction vessel kept at 80 ° C. for 2 hours each. Further, an aqueous solution of the copolymer was obtained by reacting for 1 hour while keeping the temperature at 100 ° C. The weight ratio of the monomers in the copolymer in the liquid was monomer II: IV: VII = 88: 11: 1. The copolymer in the liquid was a copolymer (C-1) (weight average molecular weight 19,000, Mw / Mn1.5).

<Manufacturing example 11>
100 parts of water was charged into a glass reaction vessel equipped with a thermometer, a stirrer, a reflux device, a nitrogen introduction tube and a dropping device, the reaction vessel was replaced with nitrogen under stirring, and the temperature was raised to 75 ° C. under a nitrogen atmosphere. Then, 90 parts of methoxypolyethylene glycol methacrylate (average number of moles of ethylene oxide added: 18), 5 parts of methacrylic acid, 21 parts of water, and 0.3 parts of 3-mercaptopropionic acid were mixed, and the monomer aqueous solution and sodium persulfate 1 were mixed. A mixed solution of 29 parts of water and 29 parts of water was continuously added dropwise to a reaction vessel kept at 75 ° C. for 2 hours each. Further, an aqueous solution of the copolymer was obtained by reacting for 1 hour while keeping the temperature at 75 ° C. The weight ratio of the monomers in the copolymer in the liquid was monomer II: IV: VII = 95: 5: 0. The copolymer in the liquid was a copolymer (C-2) (weight average molecular weight 26,000, Mw / Mn 1.7).

<Examples 1 to 12 and Comparative Examples 1 to 9>
A component: A-1, A-2, A-3, A-4, A-5, A-6, A-7, B component: B-1, B-2, C component: C-1 , C-2 in the combinations shown in Table 1 and used as Examples 1 to 12 and Comparative Examples 1 to 9.

<Concrete test>
Concrete (cement composition, hydraulic composition) to which the cement admixtures of Examples 1 to 12 and Comparative Examples 1 to 9 were added was prepared by the following procedure, and the obtained concrete was subjected to a slump test, air volume measurement, and viscosity. Evaluation and bleeding evaluation were performed.

<Concrete test procedure and evaluation method: Examples 1 to 12, Comparative Examples 1 to 9>
At the ambient temperature (20 ° C.), the coarse aggregate, fine aggregate, and cement formulated as shown in Table 2 were added and kneaded for 10 seconds by mechanical kneading with a forced biaxial mixer. Next, water and the cement admixture (initial addition) shown in Table 1 were added in the amounts shown in Table 1, kneaded for 90 seconds, and then some concrete was discharged to perform a fresh concrete test (slump test JIS). A 1101 (measured by measuring the spread of fresh concrete as a flow value), air volume JIS A 1128, concrete viscosity evaluation) was performed, and the initial concrete evaluation was performed.
For the concrete composition not used for the evaluation, after 30 minutes of kneading, the component A shown in Table 1 was mixed with 100 grams of water in the amount shown in Table 1, then added, and after further kneading for 60 seconds, the concrete was added. It was discharged and a concrete test evaluation over time was carried out in the same manner as described above. The results are shown in Tables 3 and 4.
The viscosity of concrete was evaluated by a sensory evaluation by five evaluators according to the above-mentioned criteria.
[Evaluation criteria for viscosity]
◎: The handling when the concrete is cut back with a scoop is very good, and the separation of the concrete from the scoop is very good.
◯: Good handling when cutting back concrete with a shovel, and good separation of concrete from the shovel.
×: The handling when the concrete is cut back with a shovel is poor, and the concrete is not separated from the shovel poorly.

<BD (bleeding) evaluation>
Evaluation was performed by the method specified in JIS A1123. The smaller the amount of BD (bleeding) (cm ³ / cm ² ), the more resistant the cement composition is to material separation. The results are shown in Tables 3 and 4.

In Table 1, the values in parentheses are% by weight of each admixture to the weight of cement.

C: Equal weight mixture of the following three types of cement Ordinary Portland cement (manufactured by Ube-Mitsubishi Cement Co., Ltd., specific gravity 3.16)
Ordinary Portland cement (manufactured by Taiheiyo Cement Co., Ltd., specific gravity 3.16)
Ordinary Portland cement (manufactured by Tokuyama Corporation, specific gravity 3.16)
W: Tap water S1: Lime crushed sand from Tsukumi, Oita Prefecture (fine aggregate, specific gravity 2.66)
S2: Crushed stone crushed sand from Shunan, Yamaguchi Prefecture (fine aggregate, specific gravity 2.66)
G1, G2: Crushed stone from Iwakoku, Yamaguchi Prefecture (coarse aggregate, specific gravity 2.73, 2.66)
Cement admixture (solid content equivalent) See Table 1.

The "addition rate" of the cement admixture in Tables 3 and 4 indicates the solid content addition rate of the admixture to cement. In addition, SLF indicates slump flow, respectively.

As is clear from Tables 3 and 4, the concrete of each example has better long-term dispersion retention of the concrete than the concrete of each comparative example even after 120 minutes have passed immediately after the concrete kneading. You can see that. Moreover, the slump holding performance of the concrete of each example was good. Furthermore, when comparing the amount of bleeding water over time in each example, it can be seen that the concrete in each example has a small bleeding and is less likely to cause aggregate separation. These results show that when the cement admixture for post-addition of the present invention has excellent slump retention performance and is used as a cement composition, it is possible to suppress an increase in bleeding of the cement composition for a long time. It shows that it is possible to produce a cement composition such as concrete suitable for transporting and pumping after a lapse of time.

Claims (5)

A method for producing a cement composition, which comprises performing the following steps (1) and (2).
Step (1): A step of adding a cement admixture (D) to a base cement containing a hydraulic material and kneading it.
Step (2): A step of adding and kneading a cement admixture for post-addition containing at least the following component (A) component: a polycarboxylic acid-based copolymer or a salt (A) thereof after the kneading for 5 minutes or more.
(A) Ingredient:
Monomer (I) 1 to 97% by weight represented by the following general formula (1), monomer (II) 1 to 97% by weight represented by the following general formula (2), the following general formula (3) Copolymerized with monomers (III) 1 to 97% by weight, unsaturated carboxylic acid-based monomers (IV) 0.1 to 50% by weight, and monomers (I) to (IV). A polycarboxylic acid-based copolymer or a salt (A) thereof obtained by copolymerizing 0 to 50% by weight of other possible monomers (V).
R ^{1 −} O − (A ¹ O) _{n1 −} R ² ··· (1)
(In the formula, R ¹ represents an alkenyl group having 2 to 5 carbon atoms. A ¹ O represents an oxyalkylene group having 2 to 18 carbon atoms, which is the same or different. N 1 represents an oxyalkylene group. It is the average number of added moles and represents a number of 1 to 200. R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.)

(In the formula, R ³ , R ⁴ and R ⁵ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. M represents a number from 0 to ^2. A ² O is the same. Or differently, it represents an oxyalkylene group having 2 to 18 carbon atoms. N2 is the average number of moles of the oxyalkylene group added, and represents a number of 6 to 200. X is a hydrogen atom or 1 to 1 carbon atom. Represents 30 hydrocarbon groups.)

(In the formula, R ⁶ , R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Y is a carbonization having 1 to 10 carbon atoms which may contain a hetero atom. Represents a hydrogen group.) Y in the monomer (III) of the polycarboxylic acid-based copolymer or its salt (A) is a methyl group, an ethyl group, an isopropyl group, a 2-hydroxyethyl group, a 2-hydroxypropyl group, or 2-hydroxy. The method for producing a cement composition according to claim 1, which comprises at least one monomer selected from a -1-methylethyl group. The unsaturated carboxylic acid-based monomer (IV) of the polycarboxylic acid-based copolymer or a salt thereof (A) is at least one selected from acrylic acid or a salt thereof, methacrylic acid or a salt thereof, maleic acid or a salt thereof. The method for producing a cement composition according to any one of claims 1 and 2, which contains a monomer. The cement composition according to any one of claims 1 to 3, wherein the weight average molecular weight of the polycarboxylic acid-based copolymer or the salt (A) thereof is 5,000 to 60,000 in terms of polyethylene glycol. Production method. The cement admixture (D) contains the following component (B): a polycarboxylic acid-based copolymer or a salt thereof (B) and / or a component (C): a polycarboxylic acid-based copolymer or a salt thereof (C). The method for producing a cement composition according to any one of claims 1 to 4 containing the cement composition.
(B) Ingredient:
Monomer (I) and monomer (IV), or other monomer capable of copolymerizing with monomer (I), monomer (IV) and monomer (I) and (IV) A polycarboxylic acid-based copolymer obtained by copolymerizing a body (VI) or a salt (B) thereof.
(C) component:
Monomer (II) and monomer (IV), or other monomer capable of copolymerizing with monomer (II), monomer (IV) and monomer (II) and (IV) A polycarboxylic acid-based copolymer obtained by copolymerizing a body (VII) or a salt (C) thereof.