JP7430054B2 - Manufacturing method of cement admixture - Google Patents

Description

The present invention relates to cement admixtures.

In order to improve the workability and durability of concrete, it is effective to reduce the unit amount of water in concrete. However, it is known that reducing the unit amount of water reduces the fluidity of concrete and impairs workability. Therefore, in order to ensure efficient concrete workability even when the unit water volume is reduced, various dispersants are used that have the function of dispersing cement particles.

Such dispersants include AE water reducing agents such as lignosulfonic acid dispersants and oxycarboxylic acids; high performance AE water reducing agents such as naphthalene sulfonic acid dispersants, aminosulfonic acid dispersants, and polycarboxylic acid dispersants. agents (Patent Documents 1 to 4) are known.

These dispersants are required to have initial water reduction properties and slump retention properties, and in recent years, the demand for slump retention properties has become particularly high. In concrete construction, concrete is manufactured at a manufacturing plant, then transported to the construction site by a truck agitator, unloaded onto a pump truck, and pumped to the pouring site for construction. Therefore, it takes a long time from manufacture to installation on site. For this reason, unless slump retention is imparted to concrete, workability will deteriorate significantly.

For this reason, cement admixtures have been proposed to improve the slump retention of cement compositions (cement paste, concrete, mortar, etc.). For example, copolymers of polyethylene glycol monoallyl ether monomers and (meth)acrylic acid monomers (Patent Document 5), polyalkylene glycol mono(meth)acrylic acid ester monomers and (meth) Copolymers of acrylic acid monomers (Patent Document 6) and copolymers of specific unsaturated polyalkylene glycol ether monomers and unsaturated dicarboxylic acid monomers (Patent Document 7) have been proposed. ing.

Japanese Patent Application Publication No. 9-86990 JP2005-281022A Japanese Patent Application Publication No. 11-157898 Japanese Patent Application Publication No. 2003-146717 Special Publication No. 62-025164 Japanese Patent Application Publication No. 58-074552 Patent No. 3374369

However, the cement admixtures described in Patent Documents 5 to 7 are still insufficient to satisfactorily solve the problems of slump retention and concrete viscosity. It was unclear about the relevant elements.

Therefore, an object of the present invention is to obtain a cement admixture that has excellent slump retention and, in turn, excellent workability.

As a result of diligent efforts to achieve the above object, the present inventors have found that the above problem can be solved by using a cement admixture that has an unadsorbed rate of 65% or more in a cement composition under specific conditions. This discovery led to the present invention.

That is, the present invention includes [1] to [7] below.
[1] Copolymer containing a structural unit derived from the monomer (I) represented by the following general formula (1) and a structural unit derived from the monomer (II) represented by the following general formula (2) A cement admixture containing Aggregate A, which satisfies the following condition (A).

（式中、Ｒ^１は、炭素原子数２～５のアルケニル基を表す。Ａ^１Ｏ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。ｎ１は、オキシアルキレン基の平均付加モル数であり、１～１００の数を表す。Ｒ^２は、水素原子又は炭素原子数１～３０の炭化水素基を表す。）

(In the formula, R ¹ represents an alkenyl group having 2 to 5 carbon atoms. ^{A 1} O is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. n1 is an oxyalkylene group having 2 to 18 carbon atoms. It is the average number of moles added and represents a number from 1 to 100. R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.)

（式中、Ｒ^３、Ｒ^４及びＲ^５は、それぞれ独立に、水素原子又は炭素原子数１～３のアルキル基を表す。ｍは、０～２の数を表す。Ａ^２Ｏ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、１～１００の数を表す。Ｘは、水素原子又は炭素原子数１～３０の炭化水素基を表す。）
条件（Ａ）：環境温度２０℃において下記配合にて調整したセメント組成物Ｓにセメント混和剤を添加し、攪拌混合してから３０分後に得られる分離水において、〔（分離水中の炭素量）／（ブランク分離水中の炭素量）×１００〕であらわされる未吸着率ＮＡ（３０）が、６５％以上であること。

C：下記3種の等重量混合物。

(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 Alternatively, it represents an oxyalkylene group having 2 to 18 carbon atoms. n2 is the average number of added moles of the oxyalkylene group and represents a number of 1 to 100. X is a hydrogen atom or an oxyalkylene group having 1 to 18 carbon atoms. 30 hydrocarbon groups.)
Condition (A): In the separated water obtained 30 minutes after adding the cement admixture to the cement composition S prepared with the following formulation at an environmental temperature of 20 ° C. and stirring and mixing, [(carbon content in the separated water)] The unadsorbed rate NA (30), expressed as / (carbon content in blank separated water) x 100], is 65% or more.

C: Equal weight mixture of the following three types.

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 Co., Ltd., specific gravity 3.16)
W: Tap water
S1: Kakegawa mountain sand (fine aggregate, specific gravity 2.57)
S2: Crushed sand from Iwase (fine aggregate, specific gravity 2.61)
G: Crushed stone from Ome (coarse aggregate, specific gravity 2.65)
[2] The cement admixture according to [1], wherein the copolymer (A) further contains a structural unit derived from the monomer (III) represented by the following general formula (3).

（式中、Ｒ^６、Ｒ^７、及びＲ^８は、それぞれ独立に、水素原子、－ＣＨ_３、又は－（ＣＨ_２）ｒＣＯＯＭ_２を表し、－（ＣＨ_２）ｒＣＯＯＭ_２は、－ＣＯＯＭ_１又は他の－（ＣＨ_２）ｒＣＯＯＭ_２と無水物を形成していてもよく、その場合、それらの基のＭ_１及びＭ_２は存在しない。Ｍ_１及びＭ_２は、同一若しくは異なって、水素原子、アルカリ金属、アルカリ土類金属、アンモニウム基、アルキルアンモニウム基、又は置換アルキルアンモニウム基を表す。ｒは０～２の整数を示す。）
〔３〕共重合体（Ａ）が、更に下記一般式（４）で表される単量体（ＩＶ）に由来する構成単位を含む、〔１〕～〔２〕いずれかに記載のセメント混和剤。

(In the formula, R ⁶ , R ⁷ , and R ⁸ each independently represent a hydrogen atom, -CH ₃ , or -(CH ₂ )rCOOM ₂ , and -(CH ₂ )rCOOM ₂ represents -COOM ₁ or It may form an anhydride with other -(CH ₂ )rCOOM ₂ , in which case M ₁ and M ₂ of those groups are not present. M ₁ and M ₂ are the same or different and are hydrogen atoms. , represents an alkali metal, an alkaline earth metal, an ammonium group, an alkylammonium group, or a substituted alkylammonium group. r represents an integer of 0 to 2.)
[3] The cement mixture according to any one of [1] to [2], wherein the copolymer (A) further contains a structural unit derived from the monomer (IV) represented by the following general formula (4). agent.

（式中、Ｒ^９、Ｒ^１０及びＲ^１１は、それぞれ独立に、水素原子又は炭素原子数１～３のアルキル基を表す。Ｒ^１２は、炭素原子数１～４のヘテロ原子を含んでよい炭化水素基を表す。ｓは、０～２の整数を表す。ただし、一般式（４）で表される単量体（ＩＶ）には、一般式（１）～（３）で表される単量体は含まれない。）
〔４〕下記一般式（５）であらわされる単量体（ＶＩ）を含む共重合体（Ｂ）を、さらに含むことを特徴とする〔１〕～〔３〕いずれかに記載のセメント混和剤。

(In the formula, R ⁹ , R ¹⁰ and R ¹¹ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹² may contain a hetero atom having 1 to 4 carbon atoms. Represents a hydrocarbon group. s represents an integer of 0 to 2. However, monomer (IV) represented by general formula (4) may include a group represented by general formulas (1) to (3). (Does not include monomers.)
[4] The cement admixture according to any one of [1] to [3], further comprising a copolymer (B) containing a monomer (VI) represented by the following general formula (5). .

・・・・（５）
（式中、Ｒ^３b、Ｒ^４b及びＲ^５bは、それぞれ独立に、水素原子又は炭素原子数１～３のアルキル基を表す。ｍbは、０～２の数を表す。Ａ^1bＯ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。ｎ1bは、オキシアルキレン基の平均付加モル数であり、１～１００の数を表す。Ｘは、水素原子又は炭素原子数１～３０の炭化水素基を表
す。）
〔５〕条件（Ｂ）をさらに満たすことを特徴とする〔１〕～〔４〕いずれかに記載のセメント混和剤。
条件（Ｂ）：環境温度２０℃においてセメント組成物Ｓにセメント混和剤を添加し、攪拌混合してから６０分後に得られる分離水において、〔（分離水中の炭素量）／（ブランク分離水中の炭素量）×１００〕であらわされる未吸着率ＮＡ（６０）が、５０％以上であること。
〔６〕条件（Ｃ）をさらに満たすことを特徴とする〔１〕～〔５〕いずれかに記載のセメント混和剤。
条件（Ｃ）：環境温度２０℃においてセメント組成物Ｓにセメント混和剤を添加し、攪拌混合してから９０分後に得られる分離水において、〔（分離水中の炭素量）／（ブランク分離水中の炭素量）×１００〕であらわされる未吸着率ＮＡ（９０）が、３５％以上であること。
〔７〕〔１〕～〔６〕いずれかに記載のセメント混和剤を含む、セメント組成物。

...(5)
(In the formula, R ^3b , R ^4b and R ^5b each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. mb represents a number of 0 to 2. A ^1b O is the same Alternatively, it represents an oxyalkylene group having 2 to 18 carbon atoms. n1b is the average number of added moles of the oxyalkylene group and represents a number of 1 to 100. X is a hydrogen atom or an oxyalkylene group having 1 to 18 carbon atoms. 30 hydrocarbon groups.)
[5] The cement admixture according to any one of [1] to [4], which further satisfies condition (B).
Condition (B): In the separated water obtained 60 minutes after adding the cement admixture to the cement composition S and stirring and mixing at an environmental temperature of 20°C, The unadsorbed rate NA (60), expressed as carbon content) x 100], is 50% or more.
[6] The cement admixture according to any one of [1] to [5], which further satisfies condition (C).
Condition (C): In the separated water obtained 90 minutes after adding the cement admixture to the cement composition S and stirring and mixing at an environmental temperature of 20°C, The unadsorbed rate NA (90) expressed as carbon content) x 100] is 35% or more.
[7] A cement composition comprising the cement admixture according to any one of [1] to [6].

According to the present invention, it is possible to obtain an additive for a hydraulic composition that has excellent slump retention and, in turn, excellent workability.

That is, the present invention provides a structural unit derived from a monomer (I) represented by the following general formula (1) and a structural unit derived from a monomer (II) represented by the following general formula (2), which will be described later. A cement admixture comprising a copolymer A comprising:
In the separated water obtained 30 minutes after adding it to the cement composition described below and stirring and mixing at an environmental temperature of 20 ° C., it is expressed as [(amount of carbon in separated water) / (amount of carbon in blank separated water) x 100]. This is a cement admixture characterized by an unadsorbed rate NA (30) of 65% or more.

<Polycarboxylic acid copolymer A>
Copolymer A contained in the cement admixture of the present invention is a structural unit derived from monomer (I) represented by the following general formula (1) and a monomer represented by the following general formula (2). Contains a structural unit derived from (II). Note that the ratio of each structural unit contained in the copolymer (A) usually corresponds to the charging ratio of each structural unit.

The cement admixture of the present invention may contain only one type of copolymer A, or may contain two or more types of copolymer A.

(Monomer (I) represented by general formula (1))
Hereinafter, monomer (I) will be explained first.

Monomer (I) is represented by the following general formula (1).

（式中、Ｒ^１は、炭素原子数２～５のアルケニル基を表す。Ａ^１Ｏ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。ｎ１は、オキシアルキレン基の平均付加モル数であり、１～１００の数を表す。Ｒ２は、水素原子又は炭素原子数１～３０の炭化水素基を表す。）

(In the formula, R ¹ represents an alkenyl group having 2 to 5 carbon atoms. ^{A 1} O is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. n1 is an oxyalkylene group having 2 to 18 carbon atoms. It is the average number of moles added and represents a number from 1 to 100. R2 represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.)

R ¹ in general formula (1) represents an alkenyl group having 2 to 5 carbon atoms. The alkenyl group preferably has 3 to 5 carbon atoms. Specific examples of R ¹ include, but are not limited to, an allyl group, a methallyl group, a residue of 3-methyl-3-buten-1-ol, and the like.

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

The above-mentioned "same or different" means that when multiple A ¹ O's are included in general formula (1) (when n1 is 2 or more), each A ¹ O may be the same oxyalkylene group. However, it means that different (two or more types) oxyalkylene groups may be used. In the case where a plurality of A1Os are contained in the general formula (1), an oxyethylene group (ethylene glycol unit), an oxypropylene group (propylene glycol unit), and an oxybutylene group (butylene glycol unit) are selected from the group consisting of Examples include an embodiment in which two or more oxyalkylene groups are mixed, an embodiment in which an oxyethylene group (ethylene glycol unit) and an oxypropylene group (propylene glycol unit) are mixed, or an embodiment in which an oxyethylene group (ethylene glycol unit) and an oxybutylene group are mixed. (butylene glycol units) are preferably mixed, and more preferably oxyethylene groups (ethylene glycol units) and oxypropylene groups (propylene glycol units) 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.

n1 in the general formula (1) is the average number of added moles of oxyalkylene groups, and represents a number from 1 to 100. n1 is preferably from 1 to 50, more preferably from 5 to 50, even more preferably from 8 to 50. The average number of moles added means the average number of moles of alkylene glycol units added to 1 mole of monomer.

R ² in general formula (1) represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. If the number of carbon atoms becomes 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; Examples of the carbon monomer (I) having numbers 1 to 5 include (poly)ethylene glycol allyl ether, (poly)ethylene glycol methallyl ether, (poly)ethylene glycol 3-methyl-3-butenyl ether, (poly) ) Ethylene (poly)propylene glycol allyl ether, (poly)ethylene (poly)propylene glycol methallyl ether, (poly)ethylene (poly)propylene glycol 3-methyl-3-butenyl ether, (poly)ethylene (poly)butylene glycol Allyl ether, (poly)ethylene (poly)butylene glycol methallyl ether, (poly)ethylene (poly)butylene glycol 3-methyl-3-butenyl ether, methoxy(poly)ethylene glycol allyl ether, methoxy(poly)ethylene glycol methallyl ether, methoxy(poly)ethylene glycol 3-methyl-3-butenyl ether, methoxy(poly)ethylene(poly)propylene glycol allyl ether, methoxy(poly)ethylene(poly)propylene glycol methallyl 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 methallyl ether, methoxy(poly)ethylene(poly)butylene glycol Examples include 3-methyl-3-butenyl ether. As monomer (I), one type or two or more types of these may be used, but (poly)ethylene glycol can provide an excellent balance between hydrophilicity and hydrophobicity of copolymer A. It is preferable to use one or more selected from (meth)allyl ether, (poly)ethylene glycol 3-methyl-3-butenyl ether, and (poly)ethylene(poly)propylene glycol allyl ether. Also in the specific examples of monomer (I), the average number of added moles of oxyalkylene groups (polyalkylene glycol units) is preferably 1 to 50, more preferably 5 to 50, and 8 to 50. It is more preferable that In addition, in this specification, "(poly)" means that one or more of the constituent elements or raw materials described immediately after it are bonded. Moreover, in this specification, "(meth)allyl" means "allyl or methallyl."

Copolymer A may contain only one type of structural unit derived from monomer (I),
It may be included in a combination of two or more types.

Monomer (I) is not particularly limited and can be produced by a known method. Such a method includes, for example, a method in which 1 to 100 moles of alkylene oxide is added to an unsaturated alcohol such as allyl alcohol, methallyl alcohol, or 3-methyl-3-buten-1-ol.

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

（式中、Ｒ^３、Ｒ^４及びＲ^５は、それぞれ独立に水素原子又は炭素原子数１～３のアルキル基を表す。ｍは、０～２の数を表す。Ａ^２Ｏ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、１～１００の数を表す。Ｘは、水素原子又は炭素原子数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 added moles of the oxyalkylene group and represents a number of 1 to 100. X is a hydrogen atom or a group having 1 to 30 carbon atoms. (represents a hydrocarbon group)

R ³ , R ⁴ and R ⁵ in general formula (2) each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

A2O in general formula (2) is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. Examples of the oxyalkylene group include oxyethylene group (ethylene glycol unit), oxypropylene group (propylene glycol unit), oxybutylene group (butylene glycol unit), and oxyethylene group (ethylene glycol), oxypropylene group (Propylene glycol) is preferred.

The above-mentioned "same or different" means that when multiple A ² O's are included in general formula (2) (when n2 is 2 or more), each A ² O may be the same oxyalkylene group. However, it means that different (two or more types) oxyalkylene groups may be used. In the case where a plurality of A ² O's are contained in the general formula (2), a group consisting of an oxyethylene group (ethylene glycol unit), an oxypropylene group (propylene glycol unit), and an oxybutylene group (butylene glycol unit) is used. Examples include an embodiment in which two or more selected oxyalkylene groups are mixed, an embodiment in which an oxyethylene group (ethylene glycol unit) and an oxypropylene group (propylene glycol unit) are mixed, or an embodiment in which an oxyethylene group (ethylene glycol unit) and an oxyalkylene group are mixed. It is preferable to have a mixture of butylene groups (butylene glycol units), and more preferable to be a mixture of oxyethylene groups (ethylene glycol units) and oxypropylene groups (propylene glycol units). 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 added moles of oxyalkylene groups, and represents a number from 1 to 100. n2 is preferably from 1 to 50, more preferably from 5 to 50, even more preferably from 8 to 50. The average number of moles added means the average number of moles of alkylene glycol units added to 1 mole of monomer.

Copolymer A may contain only one type of structural unit derived from monomer (II) represented by general formula (2), or may contain a combination of two or more types. In particular, it is preferable to contain two types of monomers (II) having different average numbers of added moles of oxyalkylene groups, and a monomer (IIa) having an average number of added moles of oxyalkylene groups n2 of 1 and an oxyalkylene It is more preferable to include a combination of monomers (IIb) in which the average number of added moles n2 of groups is greater than 1 and not more than 100, and it is still more preferable to use such a combination. As a result, even after a long period of time has passed since the cement admixture of the present invention is added to a hydraulic composition (eg, a cement composition), the hydraulic composition can have excellent fluidity.

Examples of the monomer (IIa) include compounds represented by formula (2) in which n2 is 1 and X is a hydrogen atom, such as 2-hydroxyethyl (meth)acrylate, 4- Examples include hydroxybutyl (meth)acrylate, preferably a compound represented by formula (2) where n2 is 1 and X is a hydrogen atom, and 2-hydroxyethyl (meth)acrylate is preferred.

When the structural unit derived from monomer (II) includes a structural unit derived from monomer (IIa) and a structural unit derived from monomer (IIb), the structural unit derived from monomer (IIa) The weight ratio ((IIa)/(IIb) of the structural units derived from monomer (IIb) to the structural units derived from monomer (IIb), provided that the weight ratio of the structural units derived from monomer (IIa) and the structural units derived from monomer (IIb) (total 100% by weight) is preferably 1/99 to 99/1, more preferably 3/97 to 50/50, and even more preferably 5/95 to 30/70. . The weight ratio of the structural units derived from monomer (IIa) to the structural units derived from monomer (IIb) usually corresponds to the charged weight ratio of monomer (IIa) to monomer (IIb). do.

X in 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 additive (dispersant) for hydraulic compositions can sufficiently exhibit the dispersibility of the hydraulic composition. Therefore, X is preferably a hydrogen 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 include esterified products of (poly)alkylene glycol.

Specifically, for example, (poly)ethylene glycol (meth)acrylate, (poly)ethylene (poly)propylene glycol (meth)acrylate, (poly)ethylene (poly)butylene glycol (meth)acrylate, methoxy (poly)ethylene (Poly)alkylene glycol (meth)acrylates, such as glycol (meth)acrylate, methoxy (poly)ethylene (poly)propylene glycol (meth)acrylate, methoxy (poly)ethylene (poly)butylene glycol (meth)acrylate, 4- Examples include hydroxybutyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate. As monomer (II), one type or a combination of two or more of these may be used, but it is preferable to use (poly)alkylene glycol (meth)acrylate, and (poly)ethylene glycol (meth)acrylate It is more preferable to use methoxy (poly)ethylene glycol (meth)acrylate. When monomer (II) is (poly)alkylene glycol (meth)acrylate, the average number of added moles of (poly)alkylene glycol in monomer (II) is preferably 1 to 50. When monomer (IIa) is (poly)alkylene glycol (meth)acrylate, the average number of moles of (poly)alkylene glycol added in monomer (IIa) is 1, and monomer (IIb) is ( In the case of poly)alkylene glycol (meth)acrylate, the average number of added moles of (poly)alkylene glycol in monomer (IIb) is preferably greater than 1 and 100 or less, more preferably from 5 to 50. It is preferably 8 to 50, more preferably 8 to 50.

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

(Monomer (III) represented by general formula (3))
The copolymer (B) may further contain a structural unit derived from the monomer (III) represented by the following general formula (3).

（式中、Ｒ^６、Ｒ^７、及びＲ^８は、それぞれ独立に、水素原子、－ＣＨ_３、又は－（ＣＨ_２）ｒＣＯＯＭ_２を表し、－（ＣＨ_２）ｒＣＯＯＭ_２は、－ＣＯＯＭ_１又は他の－（ＣＨ_２）ｒＣＯＯＭ_２と無水物を形成していてもよく、その場合、それらの基のＭ_１及びＭ_２は存在しない。Ｍ_１及びＭ_２は、同一若しくは異なって、水素原子、アルカリ金属、アルカリ土類金属、アンモニウム基、アルキルアンモニウム基、又は置換アルキルアンモニウム基を表す。ｒは０～２の整数を示す。）

(In the formula, R ⁶ , R ⁷ , and R ⁸ each independently represent a hydrogen atom, -CH ₃ , or -(CH ₂ )rCOOM ₂ , and -(CH ₂ )rCOOM ₂ represents -COOM ₁ or It may form an anhydride with other -(CH ₂ )rCOOM ₂ , in which case M ₁ and M ₂ of those groups are not present. M ₁ and M ₂ are the same or different and are hydrogen atoms. , represents an alkali metal, an alkaline earth metal, an ammonium group, an alkylammonium group, or a substituted alkylammonium group. r represents an integer of 0 to 2.)

Examples of the monomer (III) include unsaturated monocarboxylic acid monomers and unsaturated dicarboxylic acid monomers. Examples of the unsaturated monocarboxylic acid monomer include acrylic acid, methacrylic acid, crotonic acid, and salts thereof (eg, monovalent metal salts, ammonium salts, and salts with organic amines). Examples of unsaturated dicarboxylic acid monomers include maleic acid, itaconic acid, citraconic acid, and fumaric acid, salts thereof (e.g., monovalent metal salts, ammonium salts, and salts with organic amines), and Anhydrous forms thereof may be mentioned.

In addition, the copolymer (B) may contain only one type of structural unit derived from the monomer (III), or may contain two or more types.

(Monomer (IV) represented by general formula (4))
Copolymer A contained in the cement admixture of the present invention further contains a structural unit derived from a monomer represented by the following general formula (4) (hereinafter also referred to as monomer (IV)). You can stay there.

（式中、Ｒ^９、Ｒ^１０及びＲ^１１は、それぞれ独立に、水素原子又は炭素原子数１～３のアルキル基を表す。Ｒ^１２は、炭素原子数１～４のヘテロ原子を含んでよい炭化水素基を表す。ｓは、０～２の整数を表す。ただし、一般式（４）で表される単量体（ＩＶ）には、一般式（１）～（３）で表される単量体は含まれない。）

(In the formula, R ⁹ , R ¹⁰ and R ¹¹ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹² may contain a hetero atom having 1 to 4 carbon atoms. Represents a hydrocarbon group. s represents an integer of 0 to 2. However, monomer (IV) represented by general formula (4) may include a group represented by general formulas (1) to (3). (Does not include monomers.)

Preferably, R ⁹ , R ¹⁰ and R ¹¹ are each independently a hydrogen atom or a methyl group, more preferably R ⁹ , R ¹⁰ and R ¹¹ are a hydrogen atom, or R ¹⁰ is a methyl group. , and R ⁹ and R ¹¹ are hydrogen atoms.

Examples of the hydrocarbon group represented by R ¹² and which may contain a heteroatom having 1 to 4 carbon atoms include an alkyl group having 1 to 4 carbon atoms and a monohydroxyalkyl group having 1 to 4 carbon atoms. More specifically, examples include methyl group, ethyl group, propyl group, butyl group, glyceryl group, and 2-hydroxypropyl group.

The hydrocarbon group which may contain a heteroatom having 1 to 4 carbon atoms and represented by R ¹² is preferably a monohydroxyalkyl group having 1 to 4 carbon atoms, more preferably a hydroxypropyl group, More preferred is 2-hydroxypropyl group.

Examples of the monomer (IV) include monoesters of unsaturated monocarboxylic acids. Examples of monoesters of unsaturated monocarboxylic acids include methyl (meth)acrylate, ethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and glyceryl (meth)acrylate. Monomer (IV) is preferably a monohydroxyalkyl ester of (meth)acrylic acid having 1 to 4 carbon atoms, more preferably 2-hydroxypropyl (meth)acrylate.

In addition, copolymer A may contain only one type of structural unit derived from monomer (IV), and may contain two or more types.

(Other constituent units)
Copolymer A may contain structural units derived from monomers (V) other than the above-mentioned monomers (I) to (III) and monomer (IV). The copolymer (B) may contain only one type of structural unit derived from the monomer (V), or may contain two or more types. Examples of the monomer (V) include the following monomers. In addition, among the following examples, the monomers contained in monomers (I) to (III) and monomer (IV) are excluded from monomer (V).

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及び３’位アリル置換物；

Diallylbisphenols represented by, for example, 4,4'-dihydroxydiphenylpropane, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl sulfone allyl substituted at the 3 and 3'positions;

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, 4,4'-dihydroxydiphenylpropane, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl sulfone, allyl substituted at the 3-position;

General formula (V-3):

で示されるアリルフェノール；

Allylphenol represented by;

Half esters and diesters of unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid and alcohols having 1 to 30 carbon atoms;
Half amides and diamides of the above unsaturated dicarboxylic acids and amines having 1 to 30 carbon atoms;
Half esters and diesters of an alkyl (poly)alkylene glycol obtained by adding 1 to 500 moles of alkylene oxide having 2 to 18 carbon atoms to the above alcohol or amine, and the above unsaturated dicarboxylic acids;
Half esters and diesters of the above 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 glycol having 2 to 18 carbon atoms or polyalkylene glycol having 2 to 500 moles of these glycols;
Esters of alkoxy(poly)alkylene glycol, which is obtained by adding 1 to 500 moles of alkylene oxide having 2 to 18 carbon atoms to alcohol having 1 to 30 carbon atoms, and unsaturated monocarboxylic acids such as (meth)acrylic acid; Addition of alkylene oxides having 2 to 18 carbon atoms to unsaturated monocarboxylic acids such as (meth)acrylic acid, such as (poly)ethylene glycol monomethacrylate, (poly)propylene glycol monomethacrylate, and (poly)butylene glycol monomethacrylate. 1 to 500 molar adducts;
(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, etc. 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, (meth)allyl sulfonate, 2-(meth)acryloxyethyl sulfonate, 3-(meth)acryloxypropylsulfonate, 3-(meth)acryloxy-2-hydroxypropylsulfonate, 3-(meth)acryloxy-2 -Hydroxypropylsulfophenyl ether, 3-(meth)acryloxy-2-hydroxypropyloxysulfobenzoate, 4-(meth)acryloxybutyl sulfonate, (meth)acrylamidomethylsulfonic acid, (meth)acrylamidoethylsulfonic 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 having 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-chloro-1,3-butadiene;
Unsaturated amides such as (meth)acrylamide, (meth)acrylalkylamide, N-methylol (meth)acrylamide, N,N-dimethyl (meth)acrylamide;
Unsaturated cyanogens such as (meth)acrylonitrile and α-chloroacrylonitrile;
Unsaturated esters such as vinyl acetate and vinyl propionate; aminoethyl (meth)acrylate, methylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, ) Unsaturated amines such as dibutylaminoethyl acrylate and vinylpyridine;
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; and
Polydimethylsiloxane propylaminomaleamide acid, polydimethylsiloxane aminopropyleneaminomaleamide acid, polydimethylsiloxane-bis-(propylaminomaleamide acid), polydimethylsiloxane-bis-(dipropyleneaminomaleamide acid), polydimethyl Siloxane-(1-propyl-3-acrylate), Polydimethylsiloxane-(1-propyl-3-methacrylate), Polydimethylsiloxane-bis-(1-propyl-3-acrylate), Polydimethylsiloxane-bis-(1-propyl-3-acrylate) -propyl-3-methacrylate) and other siloxane derivatives.

In obtaining copolymer A, other monomers may be further used as necessary.

<Example of copolymer A>
Examples of copolymer A include copolymers a-1 and a-2 shown below. Copolymer A is preferably copolymer a-1 or copolymer a-2 shown below. Copolymer A may contain only one type or two or more types of structural units derived from the monomers represented by general formulas (1) to (3).

(Copolymer a-1)
Copolymer a-1 has a structural unit derived from monomer (I) represented by general formula (1) and a structural unit derived from monomer (II) represented by general formula (2). , contains a monomer (III) represented by general formula (3). Preferably, in copolymer a-1, the weight ratio of structural units derived from monomer (I) / structural units derived from monomer (II) / structural units derived from monomer (III) is 1 to 98/1 to 98/1 to 50, preferably 5 to 90/5 to 90/1 to 50, more preferably 5 to 50/50 to 90/1 to 50, More preferably 5 to 20/70 to 90/1 to 20. However, the total weight ratio of the structural units derived from monomer (I), the weight ratio of the structural units derived from monomer (II), and the weight ratio of the structural units derived from monomer (III) is Set it to 100.

(Copolymer a-2)
Copolymer a-2 consists of a monomer (I) represented by general formula (1), a monomer (II) represented by general formula (2), and a monomer represented by general formula (3). The monomer (III) and the monomer (IV) represented by the general formula (4) are included. Preferably, in copolymer a-2, the weight ratio of structural units derived from monomer (I)/constituent units derived from monomer (II)/(constituent units derived from monomer (III)) unit + structural unit derived from monomer (IV)) is 1 to 98/1 to 98/1 to 50, more preferably 5 to 90/5 to 90/1 to 50, more preferably The ratio is 5 to 50/50 to 90/1 to 50, more preferably 5 to 20/70 to 90/1 to 20. However, the weight ratio of the structural units derived from monomer (I), the weight ratio of the structural units derived from monomer (II), the weight ratio of the structural units derived from monomer (III), and the monomer The total weight ratio of the structural units derived from body (IV) is 100.

Copolymer a-1 and copolymer a-2 can further contain a structural unit derived from monomer (V), but the structure derived from monomer (V) in copolymer A The weight ratio of the units is preferably 0 to 50. However, the weight ratio of the structural units derived from monomer (I), the weight ratio of the structural units derived from monomer (II), the weight ratio of the structural units derived from monomer (III), the monomer The total weight ratio of the structural units derived from (IV) and the weight ratio of the structural units derived from monomer (V) is 100.

<Method for producing copolymer A>
Copolymer A in the present invention 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.

(reaction solvent)
Examples of solvents used in polymerization in a solvent include water; lower alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; aromatic hydrocarbons such as benzene, toluene, and xylene; and fats such as cyclohexane and n-hexane. Examples include cyclic or aliphatic 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 resulting copolymer, it is preferable to use one or more selected from the group consisting of water and lower alcohols, and among them, it is more preferable to use water.

When copolymerization is carried out in a solvent, each monomer and polymerization initiator may be continuously dropped into the reaction vessel, or a mixture of each monomer and the polymerization initiator may be continuously dropped into the reaction vessel. You may. Alternatively, a solvent may be charged into a reaction container, and a mixture of monomers and a solvent and a polymerization initiator solution may be continuously dropped into the reaction container, or some or all of the monomers may be charged into the reaction container, The polymerization initiator may be added dropwise continuously.

(initiator)
There are no particular limitations on the polymerization initiator that can be used in copolymerization, but when copolymerization is carried out in an aqueous solvent, for example, persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate; t-butyl Examples include water-soluble organic peroxides such as hydroperoxide. At this time, an accelerator such as sodium bisulfite or Mohr's salt may be used in combination. In addition, when copolymerizing in a solvent such as lower alcohol, aromatic hydrocarbon, alicyclic or aliphatic hydrocarbon, ester or ketone, peroxide such as benzoyl peroxide or lauryl peroxide may be used. Hydroperoxides such as cumene peroxide; aromatic azo compounds such as azobisisobutyronitrile can be used as the polymerization initiator. At this time, a promoter such as an amine compound may be used in combination. Further, when copolymerization is carried out in a water-lower alcohol mixed solvent, for example, an appropriate polymerization initiator or a combination of a polymerization initiator and an accelerator can be selected and used. The polymerization temperature varies appropriately depending on the polymerization conditions such as the solvent used and the type of polymerization initiator, but it is usually carried out in the range of 50 to 120°C.

(Chain transfer agent)
Furthermore, in the copolymerization, a chain transfer agent may be used to adjust the molecular weight if necessary. Examples of chain transfer agents used include mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycolate, and 2-mercaptoethanesulfonic acid. Known thiol compounds; phosphorous acid, hypophosphorous acid, and its salts (sodium hypophosphite, potassium hypophosphite, etc.), sulfite, hydrogen sulfite, dithionite, metabisulfite, and their Lower oxides of salts (sodium sulfite, potassium sulfite, sodium hydrogen sulfite, potassium hydrogen sulfite, sodium dithionite, potassium dithionite, sodium metabisulfite, potassium metabisulfite, etc.) and their salts; etc. It will be done. These may be used alone or in combination of two or more. Furthermore, in order to adjust the molecular weight of copolymer A, in addition to the above monomers (I) to (IV), monomers with higher chain transfer properties may be used as monomers for obtaining copolymer A. (V) may also be used. Examples of the monomer (V) with high chain transferability include (meth)allylsulfonic acid (salt) monomers. The blending ratio of monomer (V) in copolymer (A) is usually 20% by weight or less, preferably 10% by weight or less. The above blending ratio is monomer (I) blending ratio + monomer (II) blending ratio + monomer (III) blending ratio + monomer (IV) blending ratio = 100% by weight. This is the blending ratio when

(neutralization)
When copolymerizing in an aqueous solvent to obtain a copolymer, the pH during polymerization is usually strongly acidic due to the influence of monomers having unsaturated bonds, but this may be adjusted to an appropriate pH. . If pH adjustment is necessary during polymerization, adjust the pH using an acidic substance such as phosphoric acid, sulfuric acid, nitric acid, alkylphosphoric acid, alkylsulfuric acid, alkylsulfonic acid, (alkyl)benzenesulfonic acid, etc. I can do it. Among these acidic substances, phosphoric acid is preferably used because of its pH buffering effect. However, in order to eliminate the instability of ester bonds possessed by ester monomers, it is preferable to carry out the polymerization at a pH of 2 to 7. Furthermore, although there is no particular limitation on the alkaline substance that can be used to adjust the pH, alkaline substances such as NaOH and Ca(OH)2 are common. pH adjustment may be performed on the solution containing the monomer before polymerization, or may be performed on the solution containing the copolymer after polymerization. Furthermore, after the polymerization is performed by adding a part of alkaline substance before polymerization, the pH of the solution containing the copolymer may be further adjusted.

(molecular weight)
The weight average molecular weight of copolymer A is preferably 5,000 or more, more preferably 6,000 or more, and even more preferably 6,500 or more. As a result, the dispersibility of the hydraulic material of the cement admixture is fully exhibited, and it is possible to obtain a water reduction rate higher than that of AE water reducers such as ligninsulfonic acid-based or oxycarboxylic acid-based water reducers, and improve fluidity and/or workability. It is possible to fully exhibit the desired effect as a cement additive (cement dispersant). 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. This suppresses the agglomeration effect of cement particles and improves workability. The weight average molecular weight is preferably 5,000 to 60,000.

The molecular weight distribution (Mw/Mn) of copolymer A is preferably 1.0 or more, more preferably 1.20 or more. The upper limit is preferably 3.0 or less, more preferably 2.50 or less. The molecular weight distribution is preferably in the range of 1.0 to 3.0, more 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 using gel permeation chromatography (GPC) in terms of polyethylene glycol.

Although there are no particular limitations on the measurement conditions for GPC, the following conditions can be cited as examples. The weight average molecular weights in the later examples are values measured under these conditions.

Measuring device: Tosoh Column used: Shodex Column OH-pak SB-806HQ, SB-8
04HQ, SB-802.5HQ
Eluent: 0.05mM sodium nitrate/acetonitrile 8/2 (v/v)
Standard substance: Polyethylene glycol (manufactured by Tosoh, GL Science)
Detector: Differential refractometer (manufactured by Tosoh)
Calibration curve: polyethylene glycol standard

<Other ingredients>
The cement admixture of the present invention may further contain other components as required. Other components include, for example, 40 to 85% by mass of the monomer (VI) represented by the following general formula (5), 10 to 50% by mass of the monomer (III) described above, and the monomers described above. (IV) Polycarboxylic acid copolymer which is copolymer B of 0 to 10% by mass (however, monomer (I) + monomer (III) + monomer (VI) = 100% by mass) or a salt thereof.

・・・・（５）
（前記一般（５）式中、Ｒ^１b～Ｒ^３bは、それぞれ独立に、水素原子又は炭素原子数１～３のアルキル基を表す。ｍｂは、０～２の整数を表す。Ａ^１bＯは、同一又は異なっていてもよい、炭素原子数２～１８のオキシアルキレン基を表す。ｎ１は、オキシアルキレン基の平均付加モル数であり、１～８０の整数を表す。Ｘは、水素原子又は炭素原子数１～３０の炭化水素基を表す。）

...(5)
(In the general formula (5), R ^1b to R ^3b each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. mb represents an integer of 0 to 2. A ^1b O is , represents an oxyalkylene group having 2 to 18 carbon atoms, which may be the same or different. n1 is the average number of added moles of the oxyalkylene group and represents an integer of 1 to 80. X is a hydrogen atom or Represents a hydrocarbon group having 1 to 30 carbon atoms.)

In the general formula (5), among the groups represented by R ^1b to R ^3b , examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group.

A ^1b O in general formula (5) represents an oxyalkylene group having 2 to 18 carbon atoms, which may be 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). Among these, oxyethylene group (ethylene glycol) and oxypropylene group (propylene glycol) are preferred.

"They may be the same or different" means that when a plurality of A ^1b O's are included in general formula (1) (when n1 is 2 or more), each A ^1b O is the same oxyalkylene group; This means that it may be different (two or more types) of oxyalkylene groups. In the case where a plurality of A ^1b O's are contained in the general formula (1), a group consisting of an oxyethylene group (ethylene glycol unit), an oxypropylene group (propylene glycol unit), and an oxybutylene group (butylene glycol unit) is used. Examples include embodiments in which two or more selected oxyalkylene groups are mixed. Among these, an embodiment in which an oxyethylene group (ethylene glycol unit) and an oxypropylene group (propylene glycol unit) are mixed, or an embodiment in which an oxyethylene group (ethylene glycol unit) and an oxybutylene group (butylene glycol unit) are mixed is possible. Preferably, an embodiment in which oxyethylene groups (ethylene glycol units) and oxypropylene groups (propylene glycol units) are mixed is more preferable. 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.

n1b in the general formula (1) is the average number of added moles of oxyalkylene groups, and represents an integer of 1 to 80. n1b is preferably an integer of 1 to 50, more preferably an integer of 5 to 50, even more preferably an integer of 8 to 50. The average number of moles added means the average number of moles of alkylene glycol units added to 1 mole of monomer.

X in general formula (5) represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. From the viewpoint of dispersibility, X is preferably a hydrogen 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 X is a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms. More preferably, it is a methyl group.

The monomer (VI) represented by general formula (5) includes α,β-unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and one of the two OH groups of polyoxyalkylene. Examples include those obtained by ester bonding the ester, and those obtained by etherifying the remaining free OH group of this ester with an alkyl group. Typical specific examples include methoxypolyoxyethylene methacrylate (EO chain length = 9), methoxypolyoxyethylene methacrylate (EO chain length = 23), and methoxypolyethylene glycol methacrylate.

In addition, in producing a copolymer, it is also possible to use two or more types of monomers in combination.

Copolymer B contains X parts by mass of monomer (III), Y parts by mass of monomer (VI), and Z parts by mass of monomer (IV) (however, X+Y+Z=100) , 10≦X≦50, 40≦Y≦85, and 0≦Z≦10. If the range of X is less than 10 or more than 50, or if the range of Y is more than 85 or less than 40, the balance between hydrophilicity and charge of the resulting copolymer may become poor and good dispersibility may not be exhibited. . If the range of Z exceeds 10, the dispersion performance may actually deteriorate.

Note that Z is preferably 1 or more in order to enhance the effect of addition.

Regarding monomer (III) and monomer (IV) contained in copolymer B, the same ones as in copolymer A described above can be used. Furthermore, as the method for producing copolymer B and the method for measuring molecular weight, the same methods as for copolymer A described above can be employed.

Note that copolymer B does not contain a monomer corresponding to monomer (I).

Copolymer B of the present invention is preferably mixed with copolymer A in an amount of 5% by weight or more, more preferably 10% by weight or more, and even more preferably 20% by weight or more. The upper limit is preferably 90% by weight or less, more preferably 80% by weight or less, and even more preferably 70% by weight or less based on the weight of copolymer A.

<Cement admixture>
The cement admixture of the present invention thus obtained is prepared by adding the cement admixture to a cement composition S prepared according to the following formulation at an environmental temperature of 20° C. and mixing with stirring for 30 minutes. In the separated water obtained after minutes, it is important that the unadsorbed rate NA (30), expressed as [(amount of carbon in separated water)/(amount of carbon in blank separated water) x 100], is 65% or more. .

The above-mentioned cement composition has coarse aggregate, fine aggregate, cement, and water mixed as shown in the table below at an environmental temperature of 20°C.

C：下記3種の等重量混合物。
普通ポルドランドセメント（宇部三菱セメント株式会社製、比重３．１６）
普通ポルドランドセメント（太平洋セメント株式会社製、比重３．１６）
普通ポルドランドセメント（株式会社トクヤマ製、比重３．１６）
W：水道水
S1：掛川産山砂（細骨材、比重２．５７）
S2：岩瀬産砕砂（細骨材、比重２．６１）
G：青梅産砕石（粗骨材、比重２．６５）

C: Equal weight mixture of the following three types.
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 Co., Ltd., specific gravity 3.16)
W: Tap water
S1: Kakegawa mountain sand (fine aggregate, specific gravity 2.57)
S2: Crushed sand from Iwase (fine aggregate, specific gravity 2.61)
G: Crushed stone from Ome (coarse aggregate, specific gravity 2.65)

When the NA (30) satisfies this range, the unadsorbed amount is 65% or more even after 30 minutes of addition and stirring in the cement composition, ensuring long-term fluidity and achieving the slump retention of the present invention. can be obtained.

In addition, the unadsorbed amount was determined in the separated water obtained 60 minutes after adding the cement admixture to the cement composition S prepared according to the above formulation at an environmental temperature of 20°C and stirring and mixing. It is more preferable that the unadsorbed rate NA (90), which is expressed as (amount of carbon in water)/(amount of carbon in blank separated water)×100], is 50% or more.

Furthermore, the amount of unadsorbed water is determined in the separated water obtained 90 minutes after adding the cement admixture to the cement composition S prepared according to the above formulation at an environmental temperature of 20° C. and stirring and mixing. It is further preferable that the unadsorbed rate NA (90), which is expressed as (amount of carbon in water)/(amount of carbon in blank separated water)×100], is 35% or more.

When the unadsorbed amount satisfies the above conditions B to C, the effects of the present invention can be more excellently exhibited.

Note that the amount of carbon in the separated water can be obtained using a TOC (total organic carbon amount) meter.

The cement admixture of the present invention can be used in the form of an aqueous solution. Note that the cement admixture may be added to other components constituting the cement composition and hydraulic materials other than the cement composition at the time of use of the cement composition.

The cement admixture of the present invention can be added to hydraulic materials such as cement and used as cement compositions such as cement paste, mortar, concrete, and plaster.

The cement composition related to the present invention only needs to contain the cement admixture of the present invention, 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.

There are no particular limitations on the cement. For example, Portland cement (normal, early strength, ultra early strength, medium heat, sulfate resistant, and each low alkali type), various mixed cements (blast furnace cement, silica cement, fly ash cement), white Portland cement, alumina cement, Super fast hardening cement (1 clinker fast hardening cement, 2 clinker fast hardening cement, magnesium phosphate cement), grouting cement, oil well cement, low heat generation cement (low heat generation blast furnace cement, fly ash mixed low heat generation blast furnace cement, B-lite) examples include high-strength cement), ultra-high strength cement, cement-based solidifying materials, and ecocement (cement manufactured using one or more of the following as raw materials: municipal waste incineration ash and sewage sludge incineration ash). Fine powder such as blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica fume, silica powder, limestone powder, gypsum, etc. may be added to the cement.

The cement composition may also contain aggregate. The aggregate may be either fine aggregate or coarse aggregate. As aggregates, for example, sand, gravel, crushed stone; granulated slag; recycled aggregate, etc.; silica, clay, zircon, high alumina, silicon carbide, graphite, chromium, chromagite, magnesia Examples include fire-resistant aggregates such as

There is no particular limitation on the blending ratio of the cement admixture in the cement composition. For example, when the cement composition is mortar or concrete, the amount (mixed amount) of the polycarboxylic acid copolymer or its salt (A) contained in the cement admixture is based on the total weight of cement. The amount is 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. By adding this amount, the resulting cement composition has various favorable effects such as a reduction in unit water content, an increase in strength, and an improvement in durability. If the above blending ratio is less than 0.01% by weight, the resulting cement composition may not have sufficient performance.On the other hand, even if it is used in a large amount exceeding 5.0% by weight, the effect will be substantially reduced. There is a risk that the production will reach a plateau and be disadvantageous from an economic standpoint.

The above cement composition is effective as concrete such as ready-mix concrete, concrete for secondary concrete products (precast concrete), concrete for centrifugal forming, concrete for vibration compaction, steam-cured concrete, and shotcrete. . In addition, medium flow concrete (concrete with a slump value in the range of 22 to 25 cm), high flow 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-compacting concrete, and self-leveling materials. It is also effective as mortar or concrete that requires high fluidity.

The cement admixture of the present invention can also be used as a cement dispersant as it is. Furthermore, other cement dispersants, water-soluble polymers, polymer emulsions, air entraining agents, cement wetting agents, swelling agents, waterproofing agents, retarders, thickeners, flocculants, drying shrinkage reducers, strength enhancers, effects It is also possible to use it in combination with known concrete additives such as accelerators, antifoaming agents, AE agents, and other surfactants. These may be used alone or in combination of two or more.

Further, the cement admixture of the present invention can impart material separation resistance and appropriate fluidity to a cement composition, and can adjust the initial fluidity of the cement composition. Therefore, the cement admixture of the present invention may be used as a cement admixture for adjusting the initial fluidity when kneading cement materials, and during stirring and mixing of the cement composition. In order to suppress a decrease in fluidity, it may be used as an additional fluidizing agent.

Since the cement admixture of the present invention can maintain the non-adsorption rate in cement for a long time, the effects of the present invention can be exhibited no matter which method of addition is used in the cement composition.

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

<Manufacture example 1>
In a glass reaction vessel equipped with a thermometer, a stirring device, a reflux device, a nitrogen inlet tube, and a dropping device, add 157 parts of water and ethylene oxide adduct of 3-methyl-3-buten-1-ol (polyethylene glycol 3-methyl -3-Butenyl ether: 111 parts of ethylene oxide (average number of added moles of ethylene oxide: 25) was charged, the reaction vessel was purged with nitrogen under stirring, and the temperature was raised to 80° C. under a nitrogen atmosphere. Thereafter, a monomer aqueous solution containing 8 parts of acrylic acid, 63 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide: 13), 30 parts of 2-hydroxyethyl acrylate, 5 parts of ascorbic acid, and 165 parts of water, and ammonium persulfate were added. A mixed solution of 3 parts and 47 parts of water was continuously dropped into a reaction vessel maintained at 80° C. for 2 hours each. Furthermore, an aqueous solution of the copolymer was obtained by reacting for 1 hour while maintaining the temperature at 80°C. The weight ratio of each monomer was monomer I:II:III:IV:V=52:44:4:0:0. The content of polyethylene glycol 3-methyl-3-butenyl ether in the copolymer was 25% by weight, and the content of water-soluble polyethylene glycol having hydroxyl groups at both end groups was 0.7% by weight. Ta. This liquid was adjusted to pH 7 with a 30% NaOH aqueous solution. The copolymer in the liquid was copolymer (A-1) (weight average molecular weight 28,000, Mw/Mn 1.9).

<Production example 2>
129 parts of water and 52 parts of polyethylene glycol monoallyl ether (average number of added moles of ethylene oxide: 35) were charged into a glass reaction vessel equipped with a thermometer, a stirring device, a reflux device, a nitrogen inlet tube, and a dropping device, and the mixture was reacted with stirring. The temperature of the container was raised to 80°C. Thereafter, 5 parts of methacrylic acid, 3 parts of acrylic acid, 155 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide 13), 21 parts of 2-hydroxyethyl acrylate, 8 parts of methyl methacrylate, 2 parts of 3-mercaptopropionic acid A monomer aqueous solution prepared by mixing 1 part of ammonium persulfate and 24 parts of water was continuously dropped into a reaction vessel maintained at 100° C. for 2 hours each. Furthermore, an aqueous solution of the copolymer was obtained by reacting for 1 hour while maintaining the temperature at 100°C. The weight ratio of each monomer was monomer I:II:III:IV:V=21:72:3.5:3.5:0. The content of polyethylene glycol monoallyl ether in the copolymer was 20% by weight, and the content of water-soluble polyethylene glycol having both terminal groups as hydroxyl groups was 0.5% by weight. This liquid was adjusted to pH 4 with a 31% NaOH aqueous solution. The copolymer in the liquid was copolymer (A-2) (weight average molecular weight 15,000, Mw/Mn 1.8).

<Manufacture example 3>
132 parts of water and 120 parts of polyethylene glycol monoallyl ether (average number of added moles of ethylene oxide: 52) were placed in a glass reaction vessel equipped with a thermometer, a stirring device, a reflux device, a nitrogen introduction tube, and a dropping device, and the mixture was stirred. The reaction vessel was purged with nitrogen, and the temperature was raised to 100°C under a nitrogen atmosphere. Thereafter, a monomer aqueous solution containing 27 parts of acrylic acid, 51 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide 25), 2 parts of 3-mercaptopropionic acid, and 103 parts of water, 2 parts of ammonium persulfate, and water was added. 48 parts of the mixed solution were continuously dropped into a reaction vessel maintained at 100° C. over a period of 2 hours. Furthermore, an aqueous solution of the copolymer was obtained by reacting for 1 hour while maintaining the temperature at 100°C. The weight ratio of each monomer was monomer I:II:III:IV:V=61:25:14:0:0. The content of polyethylene glycol monoallyl ether in the copolymer was 8% by weight, and the content of water-soluble polyethylene glycol having hydrogen atoms at both end groups was 0.5% by weight. This liquid was adjusted to pH 7 with a 31% NaOH aqueous solution. The copolymer in the liquid was copolymer (A-3) (weight average molecular weight 65,700, Mw/Mn 2.3).

<Manufacture example 4>
733 parts of water was charged into a glass reaction vessel equipped with a thermometer, a stirring device, a reflux device, a nitrogen inlet tube, and a dropping device, the reaction vessel was purged with nitrogen while stirring, and the temperature was raised to 80° C. under a nitrogen atmosphere. Thereafter, 45 parts of acrylic acid, 95 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide: 25), 2 parts of a compound obtained by allyl substitution at the 3 and 3' positions of 4,4'-dihydroxydiphenyl sulfone, and 65 parts of water. A mixture of 3 parts of ammonium persulfate and 87 parts of water was continuously dropped into a reaction vessel maintained at 80° C. over a period of 2 hours. Further, a reaction was carried out for 1 hour while the temperature was maintained at 100° C. to obtain an aqueous solution of the copolymer. This liquid was adjusted to pH 7 with a 30% NaOH aqueous solution to obtain a copolymer (B-1) (weight average molecular weight 29,500, Mw/Mn 2.1).

The copolymers obtained in Production Examples 1 to 4 were blended at the blending ratios shown in Table 2 to obtain cement admixtures of each Example and Comparative Example.

(Examples 1 to 5, Comparative Example 1)
Each of the obtained cement admixtures was added to a cement composition S prepared according to the formulation shown in Table 3 at an environmental temperature of 20° C. so that the amount was 0.11% by weight based on the cement solid content, and mixed using a hand mixer. The mixture was stirred and mixed.
Cement compositions were collected immediately after stirring and mixing, 30 minutes later, 60 minutes later, 90 minutes later, and 120 minutes later.
The collected cement composition was treated with a centrifuge at 2500 rpm for 10 minutes to obtain supernatant separated water 1 .
The obtained separated water 1 was filtered under pressure using glass filter paper (50 μm pore size) to obtain separated water 2 and blank separated water .

The organic carbon content of the blank separated water and separated water 2 was measured using a TOC meter (total organic carbon content measurement, model name: TOC-L manufactured by Shimadzu Corporation), and the unadsorbed rate was measured using the following formula.

Unadsorbed amount NA
= (Amount of carbon in separated water 2/Amount of carbon in blank separated water ) x 100

In addition, the unadsorbed amount obtained from the cement composition collected immediately after stirring and mixing is defined as NA (0), and the amount obtained from the cement composition similarly collected after 30 minutes, 60 minutes, 90 minutes, and 120 minutes after stirring and mixing. The unadsorbed amounts were defined as NA (30), NA (60), NA (90), and NA (120), respectively. The results are shown in Table 4.

C：下記3種の等重量混合物。
普通ポルドランドセメント（宇部三菱セメント株式会社製、比重３．１６）
普通ポルドランドセメント（太平洋セメント株式会社製、比重３．１６）
普通ポルドランドセメント（株式会社トクヤマ製、比重３．１６）
W：水道水
S1：掛川産山砂（細骨材、比重２．５７）
S2：岩瀬産砕砂（細骨材、比重２．６１）
G：青梅産砕石（粗骨材、比重２．６５）

C: Equal weight mixture of the following three types.
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 Co., Ltd., specific gravity 3.16)
W: Tap water
S1: Kakegawa mountain sand (fine aggregate, specific gravity 2.57)
S2: Crushed sand from Iwase (fine aggregate, specific gravity 2.61)
G: Crushed stone from Ome (coarse aggregate, specific gravity 2.65)

(Examples 6 to 10, Comparative Examples 5 to 8)
At an environmental temperature of 20°C, Flowrick SV (manufactured by Flowrick) was added in an amount of 0.5 to 1.0% by mass based on the cement mass in order to give initial fluidity to the cement composition prepared according to the formulation shown in Table 5 below. The base concrete was adjusted so that the air content was 4.5% and the slump value was 18±2.5 cm.

Thereafter, stirring was continued for 30 minutes, and then cement admixtures 1 to 6 listed in Table 2 were added in an amount of 0.5% by weight based on the solid content of the cement.

Continue stirring and mixing after addition, obtain slump flow values immediately after addition, 30 minutes, 60 minutes, 90 minutes, and 120 minutes, and use the slump flow value immediately after addition as a reference to calculate the slump ratio over time. Calculated.

It is evaluated that the higher the slump ratio after aging, the better the slump retention of the admixture. Note that the slump flow value was measured by the following method.

A hollow cylindrical mini slump cone with a bottom diameter of 20 cm, a top diameter of 10 cm, and a height of 30 cm is filled with the above mortar, and when the mini slump cone is lifted vertically, the average value of the diameters in two directions of the mortar spread on the table was taken as the slump flow value.

C：下記3種の等重量混合物。
普通ポルドランドセメント（宇部三菱セメント株式会社製、比重３．１６）
普通ポルドランドセメント（太平洋セメント株式会社製、比重３．１６）
普通ポルドランドセメント（株式会社トクヤマ製、比重３．１６）
W：水道水
S1：掛川産山砂（細骨材、比重２．５７）
S2：岩瀬産砕砂（細骨材、比重２．６１）
G：青梅産砕石（粗骨材、比重２．６５）

C: Equal weight mixture of the following three types.
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 Co., Ltd., specific gravity 3.16)
W: Tap water
S1: Kakegawa mountain sand (fine aggregate, specific gravity 2.57)
S2: Crushed sand from Iwase (fine aggregate, specific gravity 2.61)
G: Crushed stone from Ome (coarse aggregate, specific gravity 2.65)

Claims (7)

A copolymer A containing a structural unit derived from a monomer (I) represented by the following general formula (1) and a structural unit derived from a monomer (II) represented by the following general formula (2). A method for producing a cement admixture, the method comprising: producing a composition containing a cement admixture, confirming that conditions including the following condition (A) are satisfied, and selecting the confirmed composition as a cement admixture .

(In the formula, R ¹ represents an alkenyl group having 2 to 5 carbon atoms. ^{A 1} O is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. n1 is an oxyalkylene group having 2 to 18 carbon atoms. It is the average number of moles added and represents a number from 1 to 100. 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 of 0 to 2. A ² O is the same Alternatively, it represents an oxyalkylene group having 2 to 18 carbon atoms. n2 is the average number of added moles of the oxyalkylene group and represents a number of 1 to 100. X is a hydrogen atom or an oxyalkylene group having 1 to 18 carbon atoms. 30 hydrocarbon groups.)
Condition (A): In the separated water obtained 30 minutes after adding the cement admixture to the cement composition S prepared with the following formulation at an environmental temperature of 20 ° C. and stirring and mixing, [(carbon content in the separated water)] The unadsorbed rate NA (30), expressed as / (carbon content in blank separated water) x 100], is 65% or more.

C: Equal weight mixture of the following three types.
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 Co., Ltd., specific gravity 3.16)
W: Tap water S1: Kakegawa mountain sand (fine aggregate, specific gravity 2.57)
S2: Crushed sand from Iwase (fine aggregate, specific gravity 2.61)
G : Crushed stone from Ome (coarse aggregate, specific gravity 2.65) The manufacturing method according to claim 1, wherein the copolymer (A) further contains a structural unit derived from a monomer (III) represented by the following general formula (3).

(In the formula, R ⁶ , R ⁷ , and R ⁸ each independently represent a hydrogen atom, -CH ₃ , or -(CH ₂ ) _r COOM ₂ , and -(CH ₂ ) _r COOM ₂ represents -COOM ₁ or another -(CH ₂ ) _r COOM ₂ may form an anhydride, in which case M ₁ and M ₂ of those groups are absent. M ₁ and M ₂ are the same or different , represents a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an alkylammonium group, or a substituted alkylammonium group. r represents an integer of 0 to 2.) The manufacturing method according to claim 1 or 2 , wherein the copolymer (A) further contains a structural unit derived from a monomer (IV) represented by the following general formula (4).

(In the formula, R ⁹ , R ¹⁰ and R ¹¹ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹² may contain a hetero atom having 1 to 4 carbon atoms. Represents a hydrocarbon group. s represents an integer of 0 to 2. However, monomer (IV) represented by general formula (4) may include a group represented by general formulas (1) to (3). (Does not include monomers.) The manufacturing method according to any one of claims 1 to 3 , further comprising a copolymer (B) containing a monomer (VI) represented by the following general formula (5).

(In the formula, R ^1b , R ^2b and R ^3b each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. mb represents a number of 0 to 2. A ^1B O is the same Alternatively, it represents an oxyalkylene group having 2 to 18 carbon atoms. n1b is the average number of added moles of the oxyalkylene group and represents a number of 1 to 100. X is a hydrogen atom or an oxyalkylene group having 1 to 18 carbon atoms. 30 hydrocarbon groups.) The manufacturing method according to any one of claims 1 to 4 , wherein the conditions including condition (A) further include condition (B).
Condition (B): In the separated water obtained 60 minutes after adding the cement admixture to the cement composition S and stirring and mixing at an environmental temperature of 20°C, The unadsorbed rate NA (60), expressed as carbon content) x 100], is 50% or more. The manufacturing method according to any one of claims 1 to 5 , wherein the conditions including condition (A) further include condition (C).
Condition (C): In the separated water obtained 90 minutes after adding the cement admixture to the cement composition S and stirring and mixing at an environmental temperature of 20°C, The unadsorbed rate NA (90) expressed as carbon content) x 100] is 35% or more. A copolymer A containing a structural unit derived from a monomer (I) represented by the following general formula (1) and a structural unit derived from a monomer (II) represented by the following general formula (2). A method for producing a cement composition, the method comprising confirming that the composition it contains satisfies conditions including condition (A) below, and adding the confirmed composition to a hydraulic material.

(In the formula, R ¹ represents an alkenyl group having 2 to 5 carbon atoms. A ¹ O is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. n1 is the average number of added moles of oxyalkylene groups, and represents a number from 1 to 100. 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 represents 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 different and represents an oxyalkylene group having 2 to 18 carbon atoms. n2 is the average number of added moles of oxyalkylene groups, and represents a number from 1 to 100. X represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. )
Condition (A): In the separated water obtained 30 minutes after adding the cement admixture to the cement composition S prepared with the following formulation at an environmental temperature of 20 ° C. and stirring and mixing, [(carbon content in the separated water)] The unadsorbed rate NA (30), expressed as / (carbon content in blank separated water) x 100], is 65% or more.

C: Equal weight mixture of the following three types.
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 Co., Ltd., specific gravity 3.16)
W: Tap water
S1: Kakegawa mountain sand (fine aggregate, specific gravity 2.57)
S2: Crushed sand from Iwase (fine aggregate, specific gravity 2.61)
G: Crushed stone from Ome (coarse aggregate, specific gravity 2.65)