JP2005330129A - Cement admixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cement admixture capable of improving hardness of the cured product and its durability by improving water reducing property of a cement composition, etc., and capable of preparing viscosity easy to operate in the field, and a cement composition containing such cement admixture. <P>SOLUTION: This cement admixture is essentially a copolymer formed by polymerization of a monomer component containing at least three kinds of monomers; an ethylene-based monomer (A) having a polyoxyalkylene group, an unsaturated organic acid-based monomer (B), and another unsaturated monomer (C) which is hydrolyzed in an alkaline aqueous solution, and the copolymer is formed by changing the molar ratio of the ethylene-based monomer (A) having a polyoxyalkylene group and the other unsaturated monomer (C) during the polymerization. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a cement admixture and a cement composition containing the same. More specifically, a cement admixture that can be suitably used for a cement composition such as cement paste, mortar, concrete, and the like, and a civil engineering / building structure containing such a cement admixture. The present invention relates to a widely used cement composition.

Cement admixtures are widely used as water reducing agents for cement compositions such as cement paste, mortar, and concrete, and are indispensable for building civil engineering and building structures from cement compositions. It has become. Such a cement admixture has the effect of improving the strength, durability, and the like of the cured product by increasing the fluidity of the cement composition and reducing the water content of the cement composition. Among such water reducing agents, those containing a polycarboxylic acid polymer exhibit high water reducing performance as compared with conventional water reducing agents such as naphthalene, and thus have many achievements as high performance AE water reducing agents.
In such a cement admixture, in addition to the water reducing performance for the cement composition, there is a demand for a cement admixture whose viscosity can be improved so that it is easy to work at the site where the cement composition is handled. In other words, the cement admixture used as a water reducing agent will exhibit water reducing performance by lowering the viscosity of the cement composition. What can be made to have a high viscosity is demanded in the field of manufacturing civil engineering and building structures. When the cement admixture exhibits such performance, work efficiency and the like in construction of civil engineering and building structures will be improved.
By the way, a copolymer obtained by copolymerizing a specific monomer (A) such as an ethylenically unsaturated carboxylic acid derivative having a polyoxyalkylene group and a specific monomer (B) such as (meth) acrylic acid. Concrete admixtures containing a polymer mixture and wherein the molar ratio (A) / (B) of the monomers (A) and (B) is changed at least once during the reaction are disclosed (for example, (See Patent Document 1). In such a concrete admixture, the main purpose is to change the molar ratio of the monomer (A) to the monomer (B), and a copolymerizable monomer other than these monomers. However, 0% by weight is preferred, and it is disclosed that it is better not to use a monomer other than the monomer (A) and the monomer (B). However, by improving the fluidity retention of concrete, etc. at the manufacturing site and making the state of concrete, etc. easier to work, the work efficiency, etc. at the construction site of civil engineering / building structures, etc. There was room for further improvement.

JP 2001-180998 A (page 2, 6-11)

The present invention has been made in view of the above-described situation, and it is easy to work in the field where the cement composition etc. is handled while maintaining the fluidity as an excellent slump retainability of the cement composition etc. It is an object of the present invention to provide a cement admixture that can be made viscous, and a cement composition containing such a cement admixture.

The present inventors examine a cement admixture that is required in the construction site of civil engineering and building structures, etc., that can form a cement composition that has excellent fluidity and excellent workability. Among them, a copolymer obtained by polymerizing a monomer component containing an ethylene monomer (A) having a polyoxyalkylene group and an unsaturated organic acid monomer (B) is suitable as a cement admixture. In particular, in addition to these monomers, a monomer component containing three or more monomers is copolymerized using the third unsaturated monomer (C). , A monomer (C) in which a part of the site derived from the unsaturated monomer (C) in the copolymer can be hydrolyzed in an alkaline aqueous solution is used. Among them, the ethylene monomer (A) having a polyoxyalkylene group and the third unsaturated When a copolymer in which the molar ratio with the monomer (C) is changed during polymerization, that is, a copolymer in which the molar ratio of (A) / (C) is changed during polymerization, is essential. It has been found that the agent improves the slump retention of the cement composition and the like and is effective in improving the viscosity. Further, when a mixture of three or more types of copolymers is formed by changing the molar ratio of the monomer components during the polymerization, the cement admixture has various characteristics of each copolymer, The inventors have found that the operational effects of the present invention are sufficiently exhibited, and have arrived at the present invention by conceiving that the above problems can be solved brilliantly.
That is, the present invention provides three or more monomers of an ethylene monomer having a polyoxyalkylene group (A), an unsaturated organic acid monomer (B), and another unsaturated monomer (C). A cement admixture essentially comprising a copolymer obtained by polymerizing a monomer component containing, wherein the copolymer is partially hydrolyzed in an alkaline aqueous solution. It is a cement admixture obtained by decomposing and changing the molar ratio of the ethylene monomer (A) having a polyoxyalkylene group and other unsaturated monomer (C) during polymerization.
The present invention is also a cement composition containing the above cement admixture.

The present invention is described in detail below.
In the cement admixture of the present invention, the monomer component forming the copolymer is an ethylene monomer (A) having a polyoxyalkylene group, an unsaturated organic acid monomer (B), and other non-volatile monomers. It will contain at least 3 types of monomers of a saturated monomer (C), and each monomer may use 1 type and may use 2 or more types.
In the copolymer, the dispersibility of the cement composition due to the hydrophilicity and steric repulsion of the oxyalkylene group is exhibited by the monomer unit formed by the ethylene monomer (A) having a polyoxyalkylene group. It has a function to adsorb the copolymer to cement particles by the monomer unit formed by the unsaturated organic acid monomer (B) and to increase the hydrophilicity of the copolymer. Moreover, these characteristics will be improved by the monomer unit formed by the other unsaturated monomer (C), or other characteristics will be exhibited. Furthermore, when the monomer unit formed by the unsaturated monomer (C) is hydrolyzed in an alkaline aqueous solution, these characteristics may be further improved as compared with those before decomposition, or other characteristics may be obtained. It will be demonstrated more. That is, by copolymerizing the monomer (C) in addition to the monomer (A) and the monomer (B), the copolymer of the monomer (A) and the monomer (B) is essential. As compared with the cement admixture, the performance is improved and other characteristics are imparted. Accordingly, the other unsaturated monomer (C) is an unsaturated monomer other than the ethylene monomer (A) and the unsaturated organic acid monomer (B) having a polyoxyalkylene group. The monomer unit that improves the characteristics exhibited by these monomer units or that imparts other characteristics, and the monomer unit formed by the unsaturated monomer (C) is an alkaline aqueous solution. It may be anything that hydrolyzes inside, for example, the copolymer may be hydrophobic or hydrophilic. In the present invention, the other unsaturated monomer (C) is preferably a (meth) acrylic acid ester monomer and / or a maleic acid ester monomer. By copolymerizing (meth) acrylic acid ester monomers and / or maleic acid ester monomers, the adsorptive capacity by hydrolysis will be gradually released, and concrete using this will have slump retention properties. It will be excellent. (In the present invention, the ethylene monomer (A) having a polyoxyalkylene group is suitable as an unsaturated organic acid monomer (B) and other unsaturated monomers (C). It does not include an ethylene monomer having a branched polyoxyalkylene group.
The copolymer, which is an essential component of the cement admixture of the present invention, changes the molar ratio between the ethylene monomer (A) having a polyoxyalkylene group and the other unsaturated monomer (C) during the polymerization. It is something to be made. That is, in the polymerization vessel at a certain point in the polymerization from the initial stage of the polymerization using these monomers to the completion of the polymerization, the monomer (A), the monomer (B) and the monomer (C) Assuming that the number of moles charged from the beginning of the polymerization to that point is A, B, and C, respectively, the copolymer obtained by changing the molar ratio A / C at least once during the polymerization is an essential component of the cement admixture. It will be an ingredient. The molar ratio B / C may or may not be changed during the polymerization.
Examples of changes in the molar ratio include increasing or decreasing the molar ratio, and combining increasing and decreasing, and the degree of these changes can be further changed. The change in the molar ratio may be stepwise or continuous. As a method for changing the molar ratio during the polymerization in this way, for example, any or all of the monomer (A), the monomer (B) and the monomer (C) are dropped into a polymerization vessel and dropped. It can be performed by changing the dropping rate of the monomer to be changed stepwise or continuously. In the present invention, the copolymer is polymerized by dropping the other unsaturated monomer (C), and the dropping rate of the other unsaturated monomer (C) is changed. It is preferable. As a result, the copolymer is obtained by changing the molar ratio A / C at least once during the polymerization.
In the present invention, since the molar ratio A / C may be changed at least once during the polymerization, for example, polymerization with the monomer (A) and the monomer (B) The molar ratio may be changed during the polymerization by carrying out polymerization with A), monomer (B) and monomer (C). In this case, depending on the polymerization period during which a copolymer of the monomer (A) and the monomer (B) is formed, and the monomer (A), the monomer (B), and the monomer (C) There will be a polymerization period for the copolymer to form. In the case of dropping the monomer (C), for example, after the polymerization with the monomer (A) and the monomer (B), the monomer (C) is dropped to drop the monomer (C). By performing polymerization with A), monomer (B) and monomer (C), the molar ratio A / C can be changed at least once during the polymerization.
As a ratio of each monomer in the monomer component forming the copolymer, for example, the (meth) acrylic acid ester monomer (C) is an unsaturated organic acid monomer (B). When the amount used is 100 mol%, it is 0.1 mol% or more, and preferably 100 mol% or less. More preferably, it is 1 mol% or more and 60 mol% or less. More preferably, it is 3 mol% or more and 30 mol% or less.
Furthermore, the molar ratio of the ethylene monomer (A) / unsaturated organic acid monomer (B) having a polyoxyalkylene group is 0.1 or more, and preferably 2 or less. More preferably, it is 0.3 or more and 1.2 or less.
The ethylene monomer (A) having a polyoxyalkylene group, the unsaturated organic acid monomer (B), and other unsaturated monomers (C) will be described.
Examples of the ethylene monomer (A) having a polyoxyalkylene group in the present invention include a polyalkylene glycol ester monomer having an ethylene group and ethylene having a polymerizable ethylene group and a polyalkylene glycol chain. Alcohol polyalkylene glycol adducts having a group are preferred. As the polyalkylene glycol ester monomer having an ethylene group, any monomer having a structure in which an ethylene group and a polyalkylene glycol chain are bonded via an ester bond may be used. A carboxylic acid having an ethylene group may be used. Polyalkylene glycol ester compounds are preferred, and (alkoxy) polyalkylene glycol mono (meth) acrylic acid esters having an ethylene group are particularly preferred.
The alcohol polyalkylene glycol adduct having an ethylene group may be a compound having a structure in which a polyalkylene glycol chain is added to an alcohol having an ethylene group, such as a vinyl alcohol alkylene oxide adduct, (meth) allyl alcohol alkylene oxide. Adduct, 3-buten-1-ol alkylene oxide adduct, isoprene alcohol (3-methyl-3-buten-1-ol) alkylene oxide adduct, 3-methyl-2-buten-1-ol alkylene oxide adduct 2-methyl-3-buten-2-ol alkylene oxide adduct, 2-methyl-2-buten-1-ol alkylene oxide adduct, 2-methyl-3-buten-1-ol alkylene oxide adduct are preferred. It is. In addition, the alcohol polyalkylene glycol adduct having such an ethylene group is preferably a compound represented by the following general formula (1).

In the general formula (1), R ¹ , R ² and R ³ are the same or different and each represents a hydrogen atom or a methyl group. R ⁴ represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. R ^a is the same or different and represents an alkylene group having 2 to 18 carbon atoms. m represents the average addition mole number of the oxyalkylene group represented by R ^a O, and is a number of 1 to 300. X represents a divalent alkylene group having 1 to 5 carbon atoms, or, when the group represented by R ¹ R ³ C═CR ² — is a vinyl group, a carbon atom bonded to X, oxygen Indicates that atoms are directly bonded to each other.
When two or more oxyalkylene groups represented by-(R ^a O)-in the general formula (1) are present in the alcohol polyalkylene glycol adduct having the same ethylene group,-(R ^a O) The oxyalkylene group represented by-may be in any addition form such as random addition, block addition, and alternate addition.
The oxyalkylene group represented by-(R ^a O)-is an alkylene oxide adduct having 2 to 18 carbon atoms, and the structure of such an alkylene oxide adduct is ethylene oxide, propylene oxide, butylene oxide, It is a structure formed by one or more of alkylene oxides such as isobutylene oxide, 1-butene oxide and 2-butene oxide. Among such alkylene oxide adducts, ethylene oxide, propylene oxide, and butylene oxide adducts are preferable. Further, those mainly composed of ethylene oxide are more preferable.
M is the average number of moles of the oxyalkylene group represented by R ^{a O} is the number of 1 to 300. When m exceeds 300, the polymerizability of the monomer is lowered. The preferable range of m is 2 or more, and the average added mole number of the oxyethylene group in — (R ^a O) m— is preferably 2 or more. If m is less than 2 or the average added mole number of the oxyethylene group is less than 2, there is a possibility that sufficient hydrophilicity and steric hindrance to disperse cement particles may not be obtained. There is a possibility that fluidity cannot be obtained. In order to obtain excellent fluidity, the range of m is preferably 3 or more, and more preferably 280 or less. More preferably, it is 5 or more, more preferably 10 or more, and particularly preferably 20 or more. More preferably, it is 250 or less, and particularly preferably 150 or less. Moreover, as an average addition mole number of an oxyethylene group, Preferably it is 3 or more, and 280 or less is preferable. More preferably, it is 10 or more, More preferably, it is 20 or more. More preferably, it is 250 or less, More preferably, it is 200 or less, Most preferably, it is 150 or less. The average added mole number means an average value of the number of moles of the organic group added in one mole of the monomer. In order to obtain concrete with low viscosity, the range of m is preferably 3 or more, and preferably 100 or less. More preferably, it is 4 or more and 50 or less. More preferably, it is 4 or more and 30 or less. Particularly preferably, it is 5 or more and 25 or less. In addition, as the ethylene-based monomer (A) having the polyoxyalkylene group, two or more types of monomers having different average added mole numbers m of oxyalkylene groups can be used in combination. As a suitable combination, for example, a combination of two types of monomers (A) in which a difference in m is 10 or less (preferably 5 or less), and a difference in m is 10 or more (preferably a difference in m is 20 or more). Or a combination of three or more types of monomers (A) having a difference in average added mole number m of 10 or more (preferably a difference of m of 20 or more). Furthermore, the range of m to be combined is a combination of a monomer (A) having an average added mole number m in the range of 40 to 300 and a monomer (A) in the range of 1 to 40 (provided that the difference in m is 10 or more, preferably 20 or more), a combination of a monomer (A) having an average added mole number m in the range of 20 to 300 and a monomer (A) in the range of 1 to 20 (provided that the difference in m is 10 or more, preferably 20 or more).
When R ⁴ has more than 20 carbon atoms, the cement admixture of the present invention becomes too hydrophobic, so that it may not be possible to obtain good dispersibility. A preferred form of R ⁴ is a hydrocarbon group having 1 to 20 carbon atoms or hydrogen from the viewpoint of dispersibility. More preferably, it is a hydrocarbon group having 10 or less carbon atoms, more preferably 3 or less carbon atoms, and particularly preferably 2 or less carbon atoms. Of the hydrocarbon groups, a saturated alkyl group and an unsaturated alkyl group are preferable. These alkyl groups may be linear or branched. In addition, in order to achieve excellent material separation prevention performance and an appropriate amount of air entrained in the cement composition, it is preferably a hydrocarbon group having 5 or more carbon atoms, A hydrocarbon group of 20 or less is preferable. More preferably, it is a C5-C10 hydrocarbon group. Of the hydrocarbon groups, a saturated alkyl group and an unsaturated alkyl group are preferable. These alkyl groups may be linear or branched.
The above-mentioned alcohol polyalkylene glycol adduct having an ethylene group may be any of those described above. Polyethylene glycol monovinyl ether, polyethylene glycol monoallyl ether, polyethylene glycol mono (2-methyl-2-propenyl) ether, polyethylene glycol Mono (2-butenyl) ether, polyethylene glycol mono (3-methyl-3-butenyl) ether, polyethylene glycol mono (3-methyl-2-butenyl) ether, polyethylene glycol mono (2-methyl-3-butenyl) ether, Polyethylene glycol mono (2-methyl-2-butenyl) ether, polyethylene glycol mono (1,1-dimethyl-2-propenyl) ether, polyethylene polypropylene glycol (3-methyl-3-butenyl) ether, methoxy polyethylene glycol mono (3-methyl-3-butenyl) ether, ethoxy polyethylene glycol mono (3-methyl-3-butenyl) ether, 1-propoxy polyethylene glycol mono (3 -Methyl-3-butenyl) ether, cyclohexyloxypolyethylene glycol mono (3-methyl-3-butenyl) ether, 1-octyloxypolyethylene glycol mono (3-methyl-3-butenyl) ether, nonylalkoxypolyethylene glycol mono (3 -Methyl 3-butenyl) ether, lauryl alkoxy polyethylene glycol mono (3-methyl-3-butenyl) ether, stearyl alkoxy polyethylene glycol mono (3-methyl-3-butenyl) ether Ter, phenoxy polyethylene glycol mono (3-methyl-3-butenyl) ether, naphthoxy polyethylene glycol mono (3-methyl-3-butenyl) ether, methoxy polyethylene glycol monoallyl ether, ethoxy polyethylene glycol monoallyl ether, phenoxy polyethylene glycol Preferred are monoallyl ether, methoxypolyethylene glycol mono (2-methyl-2-propenyl) ether, ethoxypolyethylene glycol mono (2-methyl-2-propenyl) ether, and phenoxypolyethylene glycol mono (2-methyl-2-propenyl) ether. The (alkoxy) polyalkylene glycol mono (meth) acrylic acid ester having the ethylene group is represented by the following general formula (2) A compound is preferred.

In the general formula (2), R ⁵ represents a hydrogen atom or a methyl group. R ^a is the same or different and represents an alkylene group having 2 to 18 carbon atoms. R ⁶ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. n represents the average added mole number of the oxyalkylene group represented by R ^a O, and is a number of 2 to 300.
In the general formula (2), n, which is the average added mole number of the oxyalkylene group represented by-(R ^a O)-and the oxyalkylene group represented by R ^a O, is the same as in the general formula (1). It is. Moreover, it is preferable from the point of the improvement of the productivity of esterification with (meth) acrylic acid that the ethylene oxide part has added to the ester bond part with (meth) acrylic acid.
N which is the average addition mole number of the oxyalkylene group represented by said R ^<a> O is a number of 2-300. When n exceeds 300, the polymerizability of the monomer is lowered. The preferable range of n is 2 or more, and the average added mole number of the oxyethylene group in — (R ^a O) n— is preferably 2 or more. When n is less than 2 or the average added mole number of the oxyethylene group is less than 2, it is possible that sufficient hydrophilicity and steric hindrance to disperse the cement particles may not be obtained. There is a possibility that fluidity cannot be obtained. In order to obtain excellent fluidity, the range of n is preferably 3 or more, and more preferably 280 or less. More preferably, it is 5 or more, More preferably, it is 10 or more, Most preferably, it is 20 or more. Further, it is more preferably 250 or less, further preferably 200 or less, and particularly preferably 150 or less. Moreover, as an average addition mole number of an oxyethylene group, 5 or more are preferable and 250 or less are preferable. More preferably, it is 10 or more, More preferably, it is 20 or more. Further, it is more preferably 200 or less, and still more preferably 150 or less. In order to obtain concrete with low viscosity, the range of n is preferably 3 or more, and preferably 100 or less. More preferably, it is 4 or more and 50 or less. More preferably, it is 4 or more and 30 or less. Particularly preferably, it is 5 or more and 25 or less. The average added mole number means an average value of the number of moles of the organic group added in one mole of the monomer. In addition, as the ethylene monomer (A) having a polyoxyalkylene group, two or more types of monomers having different average addition mole numbers n of oxyalkylene groups can be used in combination. As a suitable combination, for example, a combination of two types of monomers (A) having a difference of n of 10 or less (preferably 5 or less), a difference of n of 10 or more (preferably a difference of n of 20 or more), or Examples thereof include combinations of three or more types of monomers (A) having a difference in average added mole number n of 10 or more (preferably a difference of n of 20 or more). Further, the range of n to be combined is a combination of a monomer (A) having an average added mole number n in the range of 40 to 300 and a monomer (A) in the range of 2 to 40 (provided that the difference in n is 10 or more, preferably 20 or more), a combination of a monomer (A) having an average added mole number n in the range of 20 to 300 and a monomer (A) in the range of 2 to 20 (provided that the difference in n is 10 or more, preferably 20 or more).
When R ⁶ has more than 30 carbon atoms, the cement admixture of the present invention becomes too hydrophobic, so that good dispersibility cannot be obtained. A preferred form of R ⁶ is a hydrocarbon group having 1 to 20 carbon atoms or hydrogen from the viewpoint of dispersibility. More preferably, it is a hydrocarbon group having 10 or less carbon atoms, more preferably 3 or less carbon atoms, and particularly preferably 2 or less carbon atoms. Of the hydrocarbon groups, a saturated alkyl group and an unsaturated alkyl group are preferable. These alkyl groups may be linear or branched. In addition, in order to achieve excellent material separation prevention performance and an appropriate amount of air entrained in the cement composition, it is preferably a hydrocarbon group having 5 or more carbon atoms, A hydrocarbon group of 20 or less is preferable. More preferably, it is a C5-C10 hydrocarbon group. Of the hydrocarbon groups, a saturated alkyl group and an unsaturated alkyl group are preferable. These alkyl groups may be linear or branched.
The (alkoxy) polyalkylene glycol mono (meth) acrylic acid ester having an ethylene group may be any of those described above, but methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 1-hexanol, 2-hexanol, 3-hexanol, octanol, 2-ethyl-1-hexanol, nonyl alcohol, lauryl alcohol, cetyl alcohol, stearyl alcohol, etc. C1-C30 aliphatic alcohols, C3-C30 alicyclic alcohols such as cyclohexanol, (meth) allyl alcohol, 3-buten-1-ol, 3-methyl-3-butene-1 -C3-C30 unsaturated alcohols such as oals And an alkoxy polyalkylene glycol having an ethylene group obtained by adding 1 to 300 moles of an alkylene oxide group having 2 to 18 carbon atoms, particularly an alkoxy polyalkylene glycol mainly composed of ethylene oxide, (meth) acrylic acid, The esterified product is preferred.
As the esterified product, the following (alkoxy) polyethylene glycol (poly) (C2-C4 alkylene glycol) (meth) acrylic acid esters and the like are preferable.
Methoxy polyethylene glycol mono (meth) acrylate, methoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, methoxy {polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, methoxy {polyethylene glycol (poly) propylene glycol (Poly) butylene glycol} mono (meth) acrylate, ethoxypolyethyleneglycol mono (meth) acrylate, ethoxy {polyethyleneglycol (poly) propyleneglycol} mono (meth) acrylate, ethoxy {polyethyleneglycol (poly) butyleneglycol} mono (meta ) Acrylate, ethoxy {polyethylene glycol (poly) propylene glycol (poly) butylene glycol} mono (Meth) acrylate, propoxy polyethylene glycol mono (meth) acrylate, propoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, propoxy {polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, propoxy {polyethylene glycol ( Poly) propylene glycol (poly) butylene glycol} mono (meth) acrylate.
Butoxy polyethylene glycol mono (meth) acrylate, butoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, butoxy {polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, butoxy {polyethylene glycol (poly) propylene glycol (Poly) butylene glycol} mono (meth) acrylate, pentoxypolyethylene glycol mono (meth) acrylate, pentoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, pentoxy {polyethylene glycol (poly) butylene glycol} mono ( Meth) acrylate, pentoxy {polyethylene glycol (poly) propylene glycol (poly) butylene glycol } Mono (meth) acrylate, hexoxypolyethylene glycol mono (meth) acrylate, hexoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, hexoxy {polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, hexoxy {Polyethylene glycol (poly) propylene glycol (poly) butylene glycol} mono (meth) acrylate.
Heptoxy polyethylene glycol mono (meth) acrylate, heptoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, heptoxy {polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, heptoxy {polyethylene glycol (poly) propylene Glycol (poly) butylene glycol} mono (meth) acrylate, octoxypolyethylene glycol mono (meth) acrylate, octoxy {polyethyleneglycol (poly) propyleneglycol} mono (meth) acrylate, octoxy {polyethyleneglycol (poly) butyleneglycol} mono (Meth) acrylate, octoxy {polyethylene glycol (poly) propylene glycol (poly) butylene Recall} mono (meth) acrylate, nonanoxy polyethylene glycol mono (meth) acrylate, nonanoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, nonanoxy {polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, Nonanoxy {polyethylene glycol (poly) propylene glycol (poly) butylene glycol} mono (meth) acrylate.
Decanoxy polyethylene glycol mono (meth) acrylate, decananoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, decanoxy {polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, decanoxy {polyethylene glycol (poly) Propylene glycol (poly) butylene glycol} mono (meth) acrylate, undecanoxy polyethylene glycol mono (meth) acrylate, undecananoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, undecanoxy {polyethylene glycol (poly) butylene glycol } Mono (meth) acrylate, undecanoxy {polyethylene glycol (poly) propylene glycol (Poly) butylene glycol} mono (meth) acrylate, dodecanoxy polyethylene glycol mono (meth) acrylate, dodecananoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, dodecanoxy {polyethylene glycol (poly) butylene glycol} Mono (meth) acrylate, dodecanoxy {polyethylene glycol (poly) propylene glycol (poly) butylene glycol} mono (meth) acrylate.
Tridecanoxy polyethylene glycol mono (meth) acrylate, tridecananoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, tridecanoxy {polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, tridecanoxy {polyethylene glycol (poly) Propylene glycol (poly) butylene glycol} mono (meth) acrylate, tetradecanoxy polyethylene glycol mono (meth) acrylate, tetradecananoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, tetradecanoxy {polyethylene glycol ( Poly) butylene glycol} mono (meth) acrylate, tetradecanoxy {polyethylene glycol Poly) propylene glycol (poly) butylene glycol} mono (meth) acrylate, pentadecanoxy polyethylene glycol mono (meth) acrylate, pentadecananoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, pentadecanoxy {polyethylene Glycol (poly) butylene glycol} mono (meth) acrylate, pentadecanoxy {polyethylene glycol (poly) propylene glycol (poly) butylene glycol} mono (meth) acrylate.
Hexadecanoxy polyethylene glycol mono (meth) acrylate, hexadecananoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, hexadecanoxy {polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, hexadecanoxy {polyethylene Glycol (poly) propylene glycol (poly) butylene glycol} mono (meth) acrylate, heptadecanoxy polyethylene glycol mono (meth) acrylate, heptadecanoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, heptadecanoxy {Polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, heptadecanoxy {polyethylene group Cole (poly) propylene glycol (poly) butylene glycol} mono (meth) acrylate, octadecanoxy polyethylene glycol mono (meth) acrylate, octadecananoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, octadecanoxy {Polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, octadecanoxy {polyethylene glycol (poly) propylene glycol (poly) butylene glycol} mono (meth) acrylate.
Nonadecanoxy polyethylene glycol mono (meth) acrylate, nonadecanoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, nonadecanoxy {polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, nonadecanoxy {polyethylene glycol (poly) ) Propylene glycol (poly) butylene glycol} mono (meth) acrylate, cyclopentoxypolyethylene glycol mono (meth) acrylate, cyclopentoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, cyclopentoxy {polyethylene glycol (Poly) butylene glycol} mono (meth) acrylate, cyclopentoxy {polyethylene glycol ( B) propylene glycol (poly) butylene glycol} mono (meth) acrylate, cyclohexoxypolyethylene glycol mono (meth) acrylate, cyclohexoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, cyclohexoxy {polyethylene glycol (poly) ) Butylene glycol} mono (meth) acrylate, cyclohexoxy {polyethylene glycol (poly) propylene glycol (poly) butylene glycol} mono (meth) acrylate.
As the (alkoxy) polyalkylene glycol mono (meth) acrylic acid ester having an ethylene group, in addition to the compound represented by the general formula (1), phenoxypolyethylene glycol mono (meth) acrylate, phenoxy {polyethylene glycol (Poly) propylene glycol} mono (meth) acrylate, phenoxy {polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, phenoxy {polyethylene glycol (poly) propylene glycol (poly) butylene glycol} mono (meth) acrylate, ( (Meth) allyloxypolyethylene glycol mono (meth) acrylate, (meth) allyloxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, (me ) Allyloxy {polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, (meth) allyloxy {polyethylene glycol (poly) propylene glycol (poly) butylene glycol} mono (meth) acrylate are preferred.
Examples of the polyalkylene glycol ester monomer having an ethylene group include an (alkoxy) polyalkylene glycol monomaleate having an ethylene group in addition to the (alkoxy) polyalkylene glycol mono (meth) acrylate having an ethylene group. Acid esters and (alkoxy) polyalkylene glycol dimaleates having an ethylene group are preferred. As such a monomer, the following are suitable.
Half ester of alkyl polyalkylene glycol obtained by adding 1 to 300 mol of oxyalkylene having 2 to 4 carbon atoms to alcohol having 1 to 22 carbon atoms or amine having 1 to 22 carbon atoms and unsaturated dicarboxylic acid monomer A half ester of an unsaturated dicarboxylic acid monomer and a polyalkylene glycol having an average addition mole number of 2 to 300 carbon atoms, a diester; a triethylene glycol di (meth) acrylate, (poly) (Poly) alkylene glycol di (meth) acrylates such as ethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, (poly) ethylene glycol (poly) propylene glycol di (meth) acrylate; triethylene glycol dimaleate , Polyethylene grease (Poly) alkylene glycol dimaleate such as Rujimareto.
The unsaturated organic acid monomer (B) in the present invention may be any monomer having a polymerizable unsaturated group and a group capable of forming a carbanion. And unsaturated dicarboxylic acid monomers are preferred.
The unsaturated monocarboxylic acid-based monomer may be any monomer having one unsaturated group and one group capable of forming a carbanion in the molecule. Preferred forms include the following general formula ( It is a compound represented by 3).

In the general formula ^{(3), R 7, R} 8 and ^{R 9} are the same or different and each represents a hydrogen atom, a methyl group, or _- represents a (CH ²⁾ zCOOM 2, z represents a number of 0-2. M ¹ and M ² are the same or different and each represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group (organic ammonium group). Examples of the metal atom in M ¹ and M ² include monovalent metal atoms such as alkali metal atoms such as lithium, sodium and potassium; divalent metal atoms such as alkaline earth metal atoms such as calcium and magnesium; aluminum and iron A trivalent metal atom such as is preferable. Moreover, as an organic amine group, alkanolamine groups, such as an ethanolamine group, a diethanolamine group, and a triethanolamine group, and a triethylamine group are suitable. Further, it may be an ammonium group.
As such an unsaturated monocarboxylic acid monomer, acrylic acid, methacrylic acid, crotonic acid, etc .; these monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts (organic ammonium salts) are suitable. It is. Among these, methacrylic acid; its monovalent metal salt, divalent metal salt, ammonium salt, and organic amine salt are preferably used from the viewpoint of improving cement dispersibility, and unsaturated carboxylic acid (salt) monomer It is suitable as.
The unsaturated dicarboxylic acid monomer may be any monomer having one unsaturated group and two groups capable of forming a carbanion in the molecule. Maleic acid, itaconic acid, citraconic acid , Fumaric acid and the like, monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts thereof, or anhydrides thereof are preferable.
In addition to these, the unsaturated organic acid monomer (B) is a half ester of an unsaturated dicarboxylic acid monomer and an alcohol having 1 to 22 carbon atoms, an unsaturated dicarboxylic acid and a carbon number. Preference is given to half amides with 1 to 22 amines, half esters of unsaturated dicarboxylic acid monomers and glycols having 2 to 4 carbon atoms, and half amides of maleamic acid and glycols having 2 to 4 carbon atoms.

The alkaline aqueous solution in the present invention has a pH of 10 or more, preferably a pH of 11 or more.
The copolymer of the present invention can be partially hydrolyzed in an alkaline aqueous solution. The fact that a part of the structural unit can be hydrolyzed in the aqueous alkaline solution means that, for example, 1% or more, preferably 3% or more of the total number of structural units is hydrolyzed in an aqueous solution at 20 ° C. and pH 10. This means that 3% or more, preferably 5% or more, of the total number of structural units in an aqueous solution at ° C and pH 11 is hydrolyzed after 30 minutes.
The other unsaturated monomer (C) in the present invention is:
Unsaturated monomer in copolymer obtained by polymerizing ethylene monomer (A) having polyoxyalkylene group, unsaturated organic acid monomer (B), unsaturated monomer (C) A part of the monomer unit formed by (C) can be hydrolyzed in an alkaline aqueous solution. In particular, the alkaline aqueous solution is preferably an aqueous solution containing cement.
The hydrolyzability of the monomer unit formed by the unsaturated monomer (C) in the copolymer was evaluated by the following method, for example.
500 g of ordinary Portland cement cement (JIS R 5210) and 500 g of distilled water were placed in a 1 L container and stirred vigorously for 10 minutes, and then filtered to obtain a filtrate from which cement particles were removed (hereinafter referred to as cement filtrate).
The copolymer to be evaluated was dissolved in the cement filtrate so that the solid content of the copolymer was 1%, and the mixture was made uniform, and then allowed to stand for 30 minutes.
By quantifying the free substance derived from the monomer unit formed by the unsaturated monomer (C) produced by hydrolysis by liquid chromatography, gas chromatography,
Hydrolysis rate (%) = (number of monomer units hydrolyzed among monomer units formed by unsaturated monomer (C) in copolymer) / (copolymerization before hydrolysis) Number of monomer units formed by unsaturated monomer (C) in coalescence) x 100
Was requested. The above evaluation was performed at 20 ° C.
When the copolymer of the present invention is evaluated by the above-described method, the lower limit of the preferable hydrolysis rate range is 3% or more. More preferably, it is 6% or more, more preferably 9% or more, particularly preferably 12% or more, and most preferably 15% or more. The upper limit of a preferable hydrolysis rate is 90% or less. More preferably, it is 70% or less, more preferably 60% or less, particularly preferably 50% or less, and most preferably 40% or less.
Examples of other unsaturated monomers (C) include alkyl acrylates having a C 1-4 alkyl group such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hydroxyethyl ( (Meth) acrylate, anhydride of unsaturated dicarboxylic acid, maleic anhydride, half ester of unsaturated dicarboxylic acid monomer and alcohol having 1 to 22 carbon atoms, unsaturated dicarboxylic acid and amine having 1 to 22 carbon atoms And a half amide of an unsaturated dicarboxylic acid monomer and a glycol having 2 to 4 carbon atoms, and a half amide of maleamic acid and a glycol having 2 to 4 carbon atoms are preferred. These are selected from two or more.
Especially, acrylic acid alkyl ester having 1 to 4 carbon atoms such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hydroxyethyl (meth) acrylate, unsaturated dicarboxylic acid based monomer And a half ester of an alcohol and an alcohol having 1 to 5 carbon atoms, and a half ester of an unsaturated dicarboxylic acid monomer and a glycol having 2 to 4 carbon atoms are preferable, and at least one or more of them are selected. .
Furthermore, alkyl acrylates having 1 to 4 carbon atoms such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and the like, and hydroxyethyl (meth) acrylate are preferred, and one of these is preferred. Or two or more are selected.
In particular, alkyl acrylates having 1 to 4 carbon atoms such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and the like, and hydroxyethyl acrylate are preferable. More than species are selected.
Most preferred are methyl acrylate, ethyl acrylate, and hydroxyethyl acrylate, and at least one or two or more are selected from these.
In the present invention, in addition to an ethylene monomer having a polyoxyalkylene group (A), an unsaturated organic acid monomer (B), and an unsaturated monomer (C), a different unsaturated monomer (D ) May be added. During the polymerization, the ratio of the monomer (A) to the monomer (D) may be constant or may vary.
The unsaturated monomer (D) may be any monomer that can be copolymerized with the monomers (A), (B), and (C). As such a monomer, different from the monomer (C), an unsaturated dicarboxylic acid monomer such as maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, and carbon atoms of 23 to Half esters and diesters with 30 alcohols; half amides and diamides of the above unsaturated dicarboxylic acid monomers and amines having 23 to 30 carbon atoms; alkylenes having 2 to 18 carbon atoms in addition to the alcohols and amines Half esters and diesters of an alkyl (poly) alkylene glycol to which 1 to 500 mol of oxide has been added and the unsaturated dicarboxylic acid monomer; and the unsaturated dicarboxylic acid monomer and the carbon atom number 5-18. Half esters and diesters of glycols or polyalkylene glycols having 2 to 500 addition moles of these glycols; Half amides of acid and glycols having 5 to 18 carbon atoms or polyalkylene glycols having 2 to 500 moles of addition of these glycols; triethylene glycol di (meth) acrylate, (poly) ethylene glycol di (meth) (Poly) alkylene glycol di (meth) acrylates such as acrylate, polypropylene glycol di (meth) acrylate, (poly) ethylene glycol (poly) propylene glycol di (meth) acrylate; hexanediol di (meth) acrylate, trimethylolpropane Multifunctional (meth) acrylates such as tri (meth) acrylate and trimethylolpropane di (meth) acrylate; (poly) alkylene groups such as triethylene glycol dimaleate and polyethylene glycol dimaleate Coal dimaleates; vinyl sulfonate, (meth) allyl sulfonate, 2- (meth) acryloxyethyl sulfonate, 3- (meth) acryloxypropyl sulfonate, 3- (meth) acryloxy-2-hydroxypropyl sulfonate, 3- ( (Meth) acryloxy-2-hydroxypropylsulfophenyl ether, 3- (meth) acryloxy-2-hydroxypropyloxysulfobenzoate, 4- (meth) acryloxybutylsulfonate, (meth) acrylamidomethylsulfonic acid, (meth) acrylamidoethyl Unsaturated sulfonic acids such as sulfonic acid, 2-methylpropane sulfonic acid (meth) acrylamide, styrene sulfonic acid and the like, and monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts thereof; ) Amides of unsaturated monocarboxylic acids and amines having 1 to 30 carbon atoms such as acrylamide; vinyl aromatics such as styrene, α-methylstyrene, vinyltoluene, p-methylstyrene; 1,4- Alkanediol mono (meth) acrylates such as butanediol mono (meth) acrylate, 1,5-pentanediol mono (meth) acrylate, 1,6-hexanediol mono (meth) acrylate; butadiene, isoprene, 2-methyl- Dienes such as 1,3-butadiene and 2-chloro-1,3-butadiene; (meth) acrylamide, (meth) acrylalkylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide and the like Unsaturated amides of: (meth) acrylonitrile, α-chloroacrylonitrile Unsaturated cyanides such as ril; unsaturated esters such as vinyl acetate and vinyl propionate; aminoethyl (meth) acrylate, methylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, (meth) Unsaturated amines such as dimethylaminopropyl acrylate, dibutylaminoethyl (meth) acrylate, and vinylpyridine; divinyl aromatics such as divinylbenzene; cyanurates such as triallyl cyanurate; polydimethylsiloxanepropylaminomaleamic acid Polydimethylsiloxane aminopropylaminomaleamic acid, polydimethylsiloxane-bis- (propylaminomaleamic acid), polydimethylsiloxane-bis- (dipropyleneaminomaleamic acid), polydimethylsiloxane- (1-propyl Pill-3-acrylate), polydimethylsiloxane- (1-propyl-3-methacrylate), polydimethylsiloxane-bis- (1-propyl-3-acrylate), polydimethylsiloxane-bis- (1-propyl-3-) A siloxane derivative such as methacrylate) is preferable, and one or more of these can be used.
As the unsaturated monomer (D), (meth) acrylic acid ester, (meth) acrylic acid amide, acrylamide, styrene, styrene derivatives, (meth) allyl alcohol, (meth) allyl alcohol derivatives, sulfone group-containing single amount And an ethylene monomer having a phosphoric acid group-containing monomer and a multi-branched polyoxyalkylene group are more preferred.
Of these, acrylamide, a sulfone group-containing monomer, a phosphoric acid group-containing monomer, and an ethylene monomer having a multi-branched polyoxyalkylene group are preferred.
As a sulfone group-containing monomer, 2-acrylamido-2-methylpropanesulfonic acid or a monovalent metal salt, divalent metal salt, ammonium salt or organic ammonium salt thereof; 2-hydroxy-3-acryloxysulfonic acid or the same Monovalent metal salts, divalent metal salts, ammonium salts, organic ammonium salts; sulfoalkyl (C2-C4) (meth) acrylates such as sulfoethyl (meth) acrylate, sulfopropyl (meth) acrylate, sulfobutyl (meth) acrylate, etc. Or a monovalent metal salt, divalent metal salt, ammonium salt, organic ammonium salt thereof; isoprenesulfonic acid or a monovalent metal salt thereof, divalent metal salt, ammonium salt, organic ammonium salt; (meth) allylsulfonic acid Or monovalent metal salt, divalent metal salt, ammonium salt, organic ammonium Salts are preferred.

Suitable ethylene-based monomers having a multi-branched polyoxyalkylene group include (1) a macromer obtained by adding glycidyl methacrylate to a multi-branched polymer obtained by adding alkylene oxide to polyalkylene imine, and (2) polyalkylene imine. (Meth) acrylic acid ester macromer of a hyperbranched polymer to which an alkylene oxide is added, and (3) maleic ester macromer of a multibranched polymer in which an alkylene oxide is added to a polyalkyleneimine. As the multi-branched polymer, a polyamide polyamine or a polyhydric alcohol added with an alkylene oxide may be used.
As said polyalkylene imine, 1 type (s) or 2 or more types of C2-C8 alkylene imines, such as ethyleneimine, propyleneimine, 1,2-butyleneimine, 2,3-butyleneimine, 1,1-dimethylethyleneimine Homopolymers and copolymers of these alkyleneimines obtained by polymerizing a conventional method, preferably a polyethyleneimine polymer mainly composed of ethyleneimine. In these alkyleneimine homopolymers and copolymers, a polyalkyleneimine chain is formed, and the polyalkyleneimine chain has a branched structure and / or a three-dimensionally crosslinked structure. Is required. Further, it may be obtained by polymerizing ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine and the like. Such a polyalkyleneimine usually has a primary amino group having an active hydrogen atom or a secondary amino group (imino group) in addition to a tertiary amino group in the structure. Moreover, as a weight average molecular weight of polyalkyleneimine, 100-100,000 are preferable, More preferably, it is 300-50000, More preferably, it is 600-10000.
Examples of the alkylene oxide include 2 carbon atoms such as ethylene oxide, propylene oxide, butylene oxide, isobutylene oxide, 1-butene oxide, 2-butene oxide, trimethylethylene oxide, tetramethylene oxide, tetramethylethylene oxide, butadiene monooxide, and octylene oxide. Aliphatic alkylene epoxides such as dipentane ethylene oxide and dihexane ethylene oxide; alicyclic epoxides such as trimethylene oxide, tetramethylene oxide, tetrahydrofuran, tetrahydropyran and octylene oxide; styrene oxide, 1,1- Aromatic epoxides such as diphenylethylene oxide are preferred. These may be used alone or in combination of two or more. Among these, ethylene oxide, propylene oxide, and butylene oxide are preferable. Furthermore, what has ethylene oxide as a main component is more preferable.
In the alkylene oxide adduct, the average addition mole number of the oxyalkylene group is preferably more than 0 and 300 or less. More preferably, it is 0.5 or more, more preferably 1, or more, particularly preferably 2, or more, most preferably 3, or more. More preferably, it is 200 or less, More preferably, it is 150 or less, Especially preferably, it is 100 or less, Most preferably, it is 50 or less. When the average addition mole number of the oxyalkylene group in the alkylene oxide adduct is out of such a range, there is a possibility that the effect of improving the fluidity of the cement composition or the like is not sufficiently exhibited. In addition, the said average addition mole number means the average value of the mole number of the said oxyalkylene group added in 1 mol of groups formed by the oxyalkylene group which an alkylene oxide adduct has.
Next, the copolymerization method of the monomer component in the present invention will be described below.
As said copolymerization method, it can carry out by well-known polymerization methods, such as solution polymerization and block polymerization, using a monomer component and a polymerization initiator, for example. As the polymerization initiator, known ones can be used. Persulfates such as ammonium persulfate, sodium persulfate and potassium persulfate; hydrogen peroxide; azobis-2methylpropionamidine hydrochloride, azoisobutyronitrile Suitable are azo compounds such as benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide and the like. In addition, as a promoter, reducing agents such as sodium bisulfite, sodium sulfite, Mole salt, sodium pyrobisulfite, formaldehyde sodium sulfoxylate, ascorbic acid; and amine compounds such as ethylenediamine, sodium ethylenediaminetetraacetate, glycine, etc. You can also. These polymerization initiators and accelerators may be used alone or in combination of two or more.
In the copolymerization method, a chain transfer agent can also be used as necessary. As such a chain transfer agent, one or more known chain transfer agents can be used, but a hydrophobic chain transfer agent can also be used.

The hydrophobic chain transfer agent is preferably a thiol compound having a hydrocarbon group having 3 or more carbon atoms or a compound having a solubility in water at 25 ° C. of 10% or less. The chain transfer agent, butanethiol, octane described above Thiol, decanethiol, dodecanethiol, hexadecanethiol, octadecanethiol, cyclohexyl mercaptan, thiophenol, octyl thioglycolate, octyl 2-mercaptopropionate, octyl 3-mercaptopropionate, 2-ethylhexyl ester of mercaptopropionate, octanoic acid 2 -Thiol chain transfer agents such as mercaptoethyl ester, 1,8-dimercapto-3,6-dioxaoctane, decanetrithiol, dodecyl mercaptan; carbon tetrachloride, carbon tetrabromide, methylene chloride, bromoform, Halides mode trichloroethane; alpha-methylstyrene dimer, alpha-terpinene, .gamma.-terpinene, dipentene, unsaturated hydrocarbon compounds such as terpinolene are preferable. These may be used alone or in combination of two or more. Among these, it is preferable to include a thiol chain transfer agent having a hydrocarbon group having 3 or more carbon atoms.
The hydrophobic chain transfer agent may be used in combination with one or two hydrophilic chain transfer agents as required. As such a hydrophilic chain transfer agent, known ones can be used, such as mercaptoethanol, thioglycerol, thioglycolic acid, mercaptopropionic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, Thiol chain transfer agents such as 2-mercaptoethanesulfonic acid; primary alcohols such as 2-aminopropan-1-ol; secondary alcohols such as isopropanol; phosphorous acid, hypophosphorous acid and salts thereof (hypophosphorous acid) Sodium sulfate, potassium hypophosphite, etc.), sulfurous acid, hydrogen sulfite, dithionite, metabisulfite and its salts (sodium sulfite, sodium bisulfite, sodium dithionite, sodium metabisulfite, potassium sulfite, sulfurous acid) Potassium hydrogen, potassium dithionite, potassium metabisulfite, etc. Lower oxides and salts thereof are preferred.
As a method for adding the chain transfer agent to the reaction vessel, a continuous charging method such as dropping or divided charging can be applied. In addition, the chain transfer agent may be introduced alone into the reaction vessel, or may be previously confused with a monomer having an oxyalkylene group constituting the monomer component, a solvent, or the like.

The copolymerization method can be carried out either batchwise or continuously. In the copolymerization, a known solvent can be used as necessary. Water: alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol; benzene, toluene, xylene, cyclohexane, n- Aromatic or aliphatic hydrocarbons such as heptane; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone are preferred. These may be used alone or in combination of two or more. Among these, from the viewpoint of the solubility of the monomer component and the resulting copolymer, it is possible to use one or more solvents selected from the group consisting of water and lower alcohols having 1 to 4 carbon atoms. preferable.
In the above copolymerization method, monomer components, polymerization initiators, etc. can be added to the reaction vessel by adding all of the monomer components to the reaction vessel and adding the polymerization initiator into the reaction vessel. Polymerization method: Charge a part of the monomer components into the reaction vessel, add the polymerization initiator and the remaining monomer components into the reaction vessel, and carry out the copolymerization. Charge the reaction vessel with the polymerization solvent. A method of adding the whole amount of the monomer and the polymerization initiator is preferable. Among these methods, the molecular weight distribution of the obtained polymer can be narrowed (sharpened), and the cement dispersibility, which is an effect of increasing the fluidity of the cement composition, etc., can be improved. It is preferable to perform copolymerization by a method in which an agent and a monomer are successively dropped into a reaction vessel. In addition, since the storage stability of the polymer obtained by improving the copolymerization of the monomer component is further improved, the concentration of water in the reaction vessel during the copolymerization is maintained at 50% or less for the copolymerization. It is preferable to carry out the reaction. More preferably, it is 40% or less, More preferably, it is 30% or less.
In the above copolymerization method, the copolymerization conditions such as the copolymerization temperature are appropriately determined depending on the copolymerization method used, the solvent, the polymerization initiator, and the chain transfer agent, but the copolymerization temperature is usually 0 ° C. or higher. It is preferable that it is 150 degrees C or less. More preferably, it is 40 degreeC or more, More preferably, it is 50 degreeC or more, Most preferably, it is 60 degreeC or more. More preferably, it is 120 degrees C or less, More preferably, it is 100 degrees C or less, Most preferably, it is 85 degrees C or less.
The polymer obtained by the above copolymerization method is used as it is as a main component of the cement additive, but may be further neutralized with an alkaline substance as necessary. As the alkaline substance, it is preferable to use inorganic salts such as monovalent and divalent metal hydroxides, chlorides and carbonates; ammonia; organic amines.
As a preferable molecular weight range of the copolymer obtained by the above copolymerization reaction, it is preferable that the weight average molecular weight (Mw) in terms of polyethylene glycol by gel permeation chromatography (hereinafter referred to as “GPC”) is 5,000 to 100,000. It is more preferable that it is 9000-50000. In addition, in this specification, the weight average molecular weight of a polymer is a value measured by the following GPC measurement conditions.
[GPC molecular weight measurement conditions]
Column used: TSK guard column SWXL + TSKge1 G4000SWXL + G3000SWXL + G2000SWXL manufactured by Tosoh Corporation
Eluent: An eluent solution prepared by dissolving 115.6 g of sodium acetate trihydrate in a mixed solvent of 10999 g of water and 6001 g of acetonitrile, and adjusting the pH to 6.0 with acetic acid is used.
Implantation amount: 100 μl of 0.5% eluent solution
Eluent flow rate: 0.8 mL / min
Column temperature: 40 ° C
Standard substance: polyethylene glycol, peak top molecular weight (Mp) 272500, 219300, 85000, 46000, 24000, 12600, 4250, 7100, 1470.
Calibration curve order: Tertiary detector: 410 manufactured by Waters, Inc. 410 Differential refraction detector analysis software: MILLENIUM Ver. Manufactured by Waters, Japan 3.21
The method for producing the cement admixture of the present invention can be carried out by copolymerizing the monomer components described above. As the copolymerization method, the above-described method is suitable, and the type and amount of the monomer in the monomer component, the copolymerization conditions, and the like are appropriately set.

The cement admixture of the present invention contains the above essential components. Such a cement admixture means an agent that can be mixed with a cement composition or the like, that is, an agent comprising a cement additive or the like. A cement admixture containing the essential component as a main component is one of the preferred embodiments of the present invention. The essential component in the present invention is suitable as a main component of the cement additive, and can thereby constitute the cement admixture of the present invention. Such cement additives are described below.
The cement additive can be used in addition to a cement composition such as cement paste, mortar, and concrete. It can also be used for ultra high strength concrete.
As the cement composition, those usually used including cement, water, fine aggregate, coarse aggregate and the like are suitable. Moreover, what added fine powders, such as a fly ash, blast furnace slag, a silica fume, and a limestone, may be used.
Ultra-high-strength concrete is generally called as such in the field of cement composition, that is, the cured product is equivalent to the conventional one even if the water / cement ratio is smaller than that of conventional concrete. Or concrete having a higher strength, for example, the water / cement ratio is 25% by mass or less, further 20% by mass or less, particularly 18% by mass or less, particularly 14% by mass or less, especially about 12% by mass. However, it becomes a concrete having workability that does not hinder normal use, and the cured product thereof is 60 N / mm ² or more, further 80 N / mm ² or more, further 100 N / mm ² or more, particularly 120 N / mm ² or more. , in particular 160 N / mm ² or more, and particularly will exhibit 200 N / mm ² or more compression strength.
As the cement, portland cement such as normal, early strength, super early strength, moderate heat, white, etc .; mixed portland cement such as alumina cement, fly ash cement, blast furnace cement, silica cement and the like are suitable. As the blending amount and unit water amount per 1 m ³ of concrete of the cement, for example, in order to produce highly durable and high strength concrete, the unit water amount is 100 to 185 kg / m ³ , and the water / cement ratio is 10 to 70. % Is preferable. More preferably, the unit water amount is 120 to 175 kg / m ³ and the water / cement ratio is 20 to 65%.
The amount of the cement additive added to the cement composition is preferably such that the essential component of the present invention is 0.01% by mass or more based on 100% by mass of the total mass of the cement. It is preferable to be 10% by mass or less. If it is less than 0.01% by mass, the performance may be insufficient, and if it exceeds 10% by mass, the economical efficiency will be inferior. More preferably, it is 0.05 mass% or more, and is 8 mass% or less, More preferably, it is 0.1 mass% or more, and is 5 mass% or less.
In addition, the said mass% is a value of solid content conversion.
The cement additive can be used in combination with a commonly used cement dispersant. As the cement dispersant, the following are suitable.
Lignin sulfonate; polyol derivative; naphthalene sulfonic acid formalin condensate; melamine sulfonic acid formalin condensate; polystyrene sulfonate; aminoaryl sulfonic acid-phenol-formaldehyde condensate as described in Aminosulfonic acid type; as described in JP-A-7-267705, as a component (a), a copolymer of a polyalkylene glycol mono (meth) acrylic acid ester compound and a (meth) acrylic acid compound and / or A salt thereof, and as a component (b), a copolymer of a polyalkylene glycol mono (meth) allyl ether compound and maleic anhydride and / or a hydrolyzate thereof, and / or a salt thereof, and a component (c) As polyalkylene glycol mono (meth) allylamine A cement dispersant containing a copolymer of a polyalkylene glycol and a maleic ester of a polyalkylene glycol compound and / or a salt thereof; (meth) acrylic acid as component A as described in Japanese Patent No. 2508113 A copolymer of a polyalkylene glycol ester of (meth) acrylic acid (salt), a specific polyethylene glycol polypropylene glycol compound as the B component, and a concrete admixture comprising a specific surfactant as the C component; (Meth) acrylic acid polyethylene (propylene) glycol ester or polyethylene (propylene) glycol mono (meth) allyl ether, (meth) allyl sulfonic acid (salt), and (meth) as described in JP-A-62-216950 A copolymer made of acrylic acid (salt).
A copolymer comprising polyethylene (propylene) glycol ester of (meth) acrylic acid, (meth) allylsulfonic acid (salt), and (meth) acrylic acid (salt) as described in JP-A-1-226757; As described in JP-B-5-36377, (meth) acrylic acid polyethylene (propylene) glycol ester, (meth) allylsulfonic acid (salt) or p- (meth) allyloxybenzenesulfonic acid (salt), and Copolymer comprising (meth) acrylic acid (salt); copolymer of polyethylene glycol mono (meth) allyl ether and maleic acid (salt) as described in JP-A-4-149056; JP-A-5-170501 (Meth) acrylic acid polyethylene glycol ester, (meth) allylsulfonic acid ( ), (Meth) acrylic acid (salt), alkanediol mono (meth) acrylate, polyalkylene glycol mono (meth) acrylate, and α, β-unsaturated monomer having an amide group in the molecule Polymerization: as described in JP-A-6-191918, polyethylene glycol mono (meth) allyl ether, polyethylene glycol mono (meth) acrylate, (meth) acrylic acid alkyl ester, (meth) acrylic acid (salt), and ( Copolymer comprising meth) allylsulfonic acid (salt) or p- (meth) allyloxybenzenesulfonic acid (salt); alkoxypolyalkylene glycol monoallyl ether and maleic anhydride as described in JP-A-5-43288 Copolymer or its hydrolyzate or its salt; Polyethylene glycol monoallyl ether as described in 58-38380 JP, maleic acid, and copolymers composed of these monomers copolymerizable with monomer, or a salt thereof, or an ester thereof.
As described in JP-B-59-18338, polyalkylene glycol mono (meth) acrylic acid ester monomer, (meth) acrylic acid monomer, and a monomer copolymerizable with these monomers A copolymer comprising a polymer; a copolymer comprising a (meth) acrylic acid ester having a sulfonic acid group and a monomer copolymerizable therewith as described in JP-A-62-1119147, or Salt thereof; as described in JP-A-6-271347, an esterification reaction product of a copolymer of an alkoxy polyalkylene glycol monoallyl ether and maleic anhydride and a polyoxyalkylene derivative having an alkenyl group at the terminal; Copolymer of alkoxypolyalkylene glycol monoallyl ether and maleic anhydride as described in Kaihei 6-298555 , Esterification reaction product with a polyoxyalkylene derivative having a hydroxyl group at the terminal; as described in JP-A-62-68806, ethylene oxide or the like is added to a specific unsaturated alcohol such as 3-methyl-3-buten-1-ol. Added alkenyl ether monomers, unsaturated carboxylic acid monomers, copolymers consisting of monomers copolymerizable with these monomers, or polycarboxylic acids (salts) such as salts thereof ). These cement dispersants may be used alone or in combination of two or more.
When the cement dispersant is used in combination, it is not uniquely determined depending on the type of cement dispersant to be used, blending, test conditions, etc., but the proportion of the blending mass of the cement additive and the cement dispersant Is preferably 5 to 95:95 to 5. More preferably, it is 10-90: 90-10.

Moreover, the said cement additive can also be used in combination with another cement additive. Examples of the other cement additives include other known cement additives (materials) as shown below.
(1) Water-soluble polymer substance: polyacrylic acid (sodium), polymethacrylic acid (sodium), polymaleic acid (sodium), unsaturated carboxylic acid polymer such as sodium salt of acrylic acid / maleic acid copolymer; polyethylene Polyoxyethylene or polyoxypropylene polymers such as glycol and polypropylene glycol or copolymers thereof; Nonionic cellulose ethers such as methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, carboxyethylcellulose, hydroxypropylcellulose; yeast glucan Or xanthan gum, β-1,3 glucans (both linear and branched) may be mentioned. For example, curdlan, paramylon, bakiman, Polysaccharides produced by microbial fermentation such as cleroglucan, laminaran, etc .; polyacrylamide; polyvinyl alcohol; starch; starch phosphate ester; sodium alginate; gelatin; copolymer of acrylic acid having an amino group in its molecule and its quaternary Compounds and the like.
(2) Polymer emulsion: Copolymers of various vinyl monomers such as alkyl (meth) acrylate.
(3) retarder: oxycarboxylic such as gluconic acid, glucoheptonic acid, arabonic acid, malic acid or citric acid, and inorganic salts or organic salts thereof such as sodium, potassium, calcium, magnesium, ammonium, triethanolamine, etc. Acids and salts thereof; monosaccharides such as glucose, fructose, galactose, saccharose, xylose, apiose, ribose and isomerized sugar, oligosaccharides such as disaccharide and trisaccharide, oligosaccharides such as dextrin, and many dextran Sugars, sugars such as molasses containing them; sugar alcohols such as sorbitol; magnesium silicate; phosphoric acid and its salts or boric acid esters; aminocarboxylic acids and their salts; alkali-soluble proteins; humic acids; Phenol; polyhydric alcohol such as glycerine; aminotri ( Tylene phosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid) and their alkali metal salts, alkaline earth metal salts and other phosphonic acids and their derivatives etc.
(4) Early strengthening agents / accelerators: soluble calcium salts such as calcium chloride, calcium nitrite, calcium nitrate, calcium bromide and calcium iodide; chlorides such as iron chloride and magnesium chloride; sulfates; potassium hydroxide; Sodium hydroxide; carbonate; thiosulfate; formate such as formic acid and calcium formate; alkanolamine; alumina cement; calcium aluminate silicate.
(5) Mineral oil-based antifoaming agent: straw oil, liquid paraffin, etc.
(6) Fat and oil-based antifoaming agents: animal and vegetable oils, sesame oil, castor oil, and alkylene oxide adducts thereof.
(7) Fatty acid-based antifoaming agent: oleic acid, stearic acid, and these alkylene oxide adducts.
(8) Fatty acid ester antifoaming agent: glycerin monoricinoleate, alkenyl succinic acid derivative, sorbitol monolaurate, sorbitol trioleate, natural wax and the like.
(9) Oxyalkylene antifoaming agents: polyoxyalkylenes such as (poly) oxyethylene (poly) oxypropylene adducts; diethylene glycol heptyl ether, polyoxyethylene oleyl ether, polyoxypropylene butyl ether, polyoxyethylene polyoxypropylene (Poly) oxyalkyl ethers such as 2-ethylhexyl ether and oxyethyleneoxypropylene adducts to higher alcohols having 12 to 14 carbon atoms; (poly) oxyalkylenes such as polyoxypropylene phenyl ether and polyoxyethylene nonylphenyl ether (Alkyl) aryl ethers; 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,5-dimethyl-3-hexyne-2,5-diol, 3-methyl-1- Spotted Acetylene ethers obtained by addition polymerization of alkylene oxide to acetylene alcohol such as -3-ol; (poly) oxyalkylene fatty acid esters such as diethylene glycol oleate, diethylene glycol laurate, ethylene glycol distearate; polyoxyethylene sorbitan (Poly) oxyalkylene sorbitan fatty acid esters such as monolaurate and polyoxyethylene sorbitan trioleate; (poly) oxyalkylene alkyl (aryl) such as sodium polyoxypropylene methyl ether sulfate and sodium polyoxyethylene dodecylphenol ether sulfate ) Ether sulfate esters; (Poly) oxy such as (poly) oxyethylene stearyl phosphate Ruki alkylene alkyl phosphate esters; polyoxyethylene such as polyoxyethylene lauryl amine (poly) oxyalkylene alkyl amines; polyoxyalkylene amide.
(10) Alcohol-based antifoaming agent: octyl alcohol, hexadecyl alcohol, acetylene alcohol, glycols and the like.
(11) Amide antifoaming agent: acrylate polyamine and the like.
(12) Phosphate ester antifoaming agent: tributyl phosphate, sodium octyl phosphate, etc.
(13) Metal soap type antifoaming agent: aluminum stearate, calcium oleate, etc.
(14) Silicone antifoaming agent: dimethyl silicone oil, silicone paste, silicone emulsion, organically modified polysiloxane (polyorganosiloxane such as dimethylpolysiloxane), fluorosilicone oil and the like.
(15) AE agent: resin soap, saturated or unsaturated fatty acid, sodium hydroxystearate, lauryl sulfate, ABS (alkyl benzene sulfonic acid), LAS (linear alkyl benzene sulfonic acid), alkane sulfonate, polyoxyethylene alkyl (phenyl) ether Polyoxyethylene alkyl (phenyl) ether sulfate or a salt thereof, polyoxyethylene alkyl (phenyl) ether phosphate or a salt thereof, protein material, alkenylsulfosuccinic acid, α-olefin sulfonate, and the like.
(16) Other surfactants: aliphatic monohydric alcohols having 6 to 30 carbon atoms in the molecule such as octadecyl alcohol and stearyl alcohol, and those having 6 to 30 carbon atoms in the molecule such as abiethyl alcohol Intramolecular such as alicyclic monohydric alcohol, dodecyl mercaptan, etc. Intramolecular such as monovalent mercaptan having 6-30 carbon atoms in the molecule, such as nonylphenol, alkylphenol having 6-30 carbon atoms in the molecule, dodecylamine, etc. 10 mol or more of an alkylene oxide such as ethylene oxide or propylene oxide was added to a carboxylic acid having 6 to 30 carbon atoms in the molecule such as an amine having 6 to 30 carbon atoms, lauric acid or stearic acid. Polyalkylene oxide derivatives; having an alkyl group or alkoxyl group as a substituent Alkyl diphenyl ether sulfonates in which two phenyl groups having a sulfone group are ether-bonded; various anionic surfactants; various cationic surfactants such as alkylamine acetate and alkyltrimethylammonium chloride; various nonions Surfactants; various amphoteric surfactants.
(17) Waterproofing agent: fatty acid (salt), fatty acid ester, oil and fat, silicon, paraffin, asphalt, wax and the like.
(18) Rust preventive: nitrite, phosphate, zinc oxide and the like.
(19) Crack reducing agent: polyoxyalkyl ethers; alkanediols such as 2-methyl-2,4-pentanediol.
(20) Expansion material: Ettlingite, coal, etc.
Other known cement additives (materials) include cement wetting agents, thickeners, separation reducing agents, flocculants, drying shrinkage reducing agents, strength enhancers, self-leveling agents, rust preventives, colorants, and antifungal agents. Agents, blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica fume, silica powder, gypsum and the like. These known cement additives (materials) may be used alone or in combination of two or more.
The above-mentioned cement additive may be used in combination with the above-described known cement dispersant and cement additive (material), in addition to those that improve the dispersibility of the cement composition, foam suppression, and the like.
As a method for adding the cement additive and the cement dispersant to the cement composition, it is preferable to mix these cement additives and the cement dispersant into a cement admixture so as to be easily mixed into the cement composition. .
In the cement composition, the following (1) to (6) may be mentioned as particularly preferred embodiments for components other than cement and water.

  (1) <1> A combination comprising two components of the cement admixture of the present invention and <2> an oxyalkylene-based antifoaming agent. The blending mass ratio of the oxyalkylene antifoaming agent <2> is preferably 0.01 to 20% by mass with respect to the cement admixture <1>.

  (2) A combination comprising essentially the three components of <1> the cement admixture of the present invention, <2> an oxyalkylene antifoaming agent, and <3> an AE agent. As the oxyalkylene-based antifoaming agent, polyoxyalkylenes, polyoxyalkylene alkyl ethers, polyoxyalkylene acetylene ethers, polyoxyalkylene alkylamines and the like can be used, but polyoxyalkylene alkylamines are particularly preferable. Is preferred. The blending mass ratio of the cement admixture <1> and the antifoaming agent <2> is preferably 0.01 to 20% by mass with respect to the cement admixture <1>. On the other hand, the blending mass ratio of the AE agent <3> is preferably 0.001 to 2 mass% with respect to the cement.

  (3) A combination comprising two components, <1> the cement admixture of the present invention and <2> a material separation reducing agent. As a material separation reducing agent, various thickeners such as nonionic cellulose ethers, an average addition of a hydrophobic substituent consisting of a hydrocarbon chain having 4 to 30 carbon atoms and an alkylene oxide having 2 to 18 carbon atoms as a partial structure A compound having a polyoxyalkylene chain having 2 to 300 moles added can be used. The blending mass ratio between the cement admixture of <1> and the material separation reducing agent of <2> is preferably 10/90 to 99.99 / 0.01, and 50/50 to 99.9 / 0. .1 is more preferable. The cement composition of this combination is suitable as high fluidity concrete, self-filling concrete and self-leveling material.

  (4) <1> A combination comprising two components of the cement admixture of the present invention and <2> retarder. As the retarder, oxycarboxylic acids such as gluconic acid (salt) and citric acid (salt), sugars such as glucose, sugar alcohols such as sorbitol, phosphonic acids such as aminotri (methylenephosphonic acid), and the like can be used. However, oxycarboxylic acids are particularly suitable. The blending mass ratio of the cement admixture of <1> and the retarder of <2> is preferably in the range of 10/90 to 99.9 / 0.1, and in the range of 20/80 to 99/1. More preferred.

  (5) A combination comprising two components, <1> the cement admixture of the present invention and <2> an accelerator. As the promoter, soluble calcium salts such as calcium chloride, calcium nitrite and calcium nitrate, chlorides such as iron chloride and magnesium chloride, formates such as thiosulfate, formic acid and calcium formate, and the like can be used. The blending mass ratio of the <1> cement admixture and the <2> accelerator is preferably in the range of 0.1 / 99.9 to 90/10, and in the range of 1/99 to 70/30. More preferred.

(6) <1> The cement admixture of the present invention, <2> a combination comprising essentially two components of a sulfonic acid-based dispersant having a sulfonic acid group in the molecule. Examples of the sulfonic acid-based dispersant include amino sulfonic acid-based compounds such as lignin sulfonate, naphthalene sulfonic acid formalin condensate, melamine sulfonic acid formalin condensate, polystyrene sulfonate, aminoaryl sulfonic acid-phenol-formaldehyde condensate. A dispersant or the like can be used. The blending mass ratio of the cement admixture of <1> and the sulfonic acid dispersant of <2> is preferably in the range of 5/95 to 95/5, more preferably in the range of 10/90 to 90/10. preferable.
The cement admixture of the present invention can be suitably applied to various cement compositions and the like so that the fluidity is maintained with excellent slump retention properties of the cement composition and the like and handled. Since it is possible to make the viscosity easy to work on site, by using the cement admixture of the present invention, the water reduction of the cement composition is improved and the strength and durability of the cured product are improved. Since it is excellent and has a viscosity that makes it easy to work at the site where the cement composition is handled, work efficiency and the like in construction of civil engineering and building structures will be improved. Such a cement composition containing the cement admixture of the present invention is also one aspect of the present invention.

Since the cement admixture of the present invention has the above-described configuration, the cement composition such as cement paste, mortar, concrete and the like is improved in water reduction, and the cured product has excellent strength and durability. Since it is possible to maintain fluidity by increasing slump retention of objects, etc., and it can be made viscous so that it is easy to work at the site where it is handled, civil engineering and building structures with excellent basic performance Work efficiency can be improved in construction.

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

200 parts of water was charged into a glass reactor equipped with a thermometer, a stirrer, a dripping device, a nitrogen introducing tube and a reflux cooling device, and the inside of the reactor was purged with nitrogen under stirring and heated to 80 ° C. in a nitrogen atmosphere. Monomer aqueous solution in which 306.5 parts of methoxypolyethylene glycol monomethacrylate (average added mole number of ethylene oxide 25), 46.5 parts of methacrylic acid, 88.3 parts of water, and 2.1 parts of 3-mercaptopropionic acid as a chain transfer agent are mixed. Was added dropwise over 5 hours. Simultaneously with the start of dropping of the monomer aqueous solution, 80 parts of a 1.8% hydrogen peroxide aqueous solution and 80 parts of a 2.3% L ascorbic acid aqueous solution were dropped over 6 hours as initiators. Simultaneously with the start of the dropwise addition of the aqueous monomer solution, 196 parts of hydroxyethyl acrylate was added dropwise over 3 hours. Thereafter, the temperature was maintained at 80 ° C. for 1 hour to complete the polymerization reaction, and a polymer aqueous solution (P-1) having a weight average molecular weight of 20,000 was obtained.

A glass reactor equipped with a thermometer, a stirrer, a dropping device, a nitrogen introduction tube and a reflux cooling device was charged with 227 parts of water, and the inside of the reactor was purged with nitrogen under stirring and heated to 65 ° C. in a nitrogen atmosphere. 354.5 parts of ethyleneprene added to the hydroxyl group of isoprenol (average number of moles of ethylene oxide added 50), 31.4 parts of acrylic acid, 96.5 parts of water, 1.1 parts of 3-mercaptopropionic acid as a chain transfer agent Was added dropwise over 3 hours. Simultaneously with the start of dropping of the monomer aqueous solution, 80 parts of a 0.5% aqueous hydrogen peroxide solution and 80 parts of a 0.7% L ascorbic acid aqueous solution were added dropwise over 4 hours as initiators. Simultaneously with the start of dropping of the monomer aqueous solution, 130 parts of hydroxyethyl acrylate was dropped in 2 hours. Thereafter, the temperature was maintained at 80 ° C. for 1 hour to complete the polymerization reaction, and an aqueous polymer solution (P-2) having a weight average molecular weight of 27,000 was obtained.

In Examples 3 and 4 and Comparative Examples 1, 2, 3, and 4, in the same manner as in Example 1, the aqueous polymer solution was used at the monomer, monomer amount, monomer dropping time, and polymerization temperature shown in Table 1. (P-3), (P-4), (H-1), (H-2), (H-3) and (H-4) were synthesized.
PGM-25E in the table is methoxypolyethylene glycol monomethacrylate (average addition mole number of ethylene oxide 25), IPN-50 is the one obtained by adding ethylene oxide to the hydroxyl group of isoprenol (average addition mole number of ethylene oxide 50), MAL-50 is obtained by adding ethylene oxide to the hydroxyl group of methallyl alcohol. The average number of moles of ethylene oxide added is 50), MAA is methacrylic acid, AA is acrylic acid, HEA is hydroxyethyl acrylate, and AM is methyl acrylate. MMA represents methyl methacrylate.
By the concrete test, the polymer aqueous solutions obtained in Examples 1 to 4 and Comparative Examples 1 to 4 were evaluated as cement admixtures. The results are shown in Table 1.
Concrete test conditions Tap water 172kg / m ³
Cement (manufactured by Taiheiyo Cement) 491kg / m ³
Fine aggregate (mountain sand from Ogasayama) 744.6kg / m ³
Coarse aggregate (Ome-produced single-grain crushed stone No. 5-6, blend ratio 53/47) 909.8 kg / m ³
The mixture was kneaded for 90 seconds with a pan mixer.
Measure the slump just after kneading to 24cm.

In Table 1, the charged amount represents the weight part of the monomer used for the polymerization, and the dropping time represents the time when the monomer was dropped.
The amount added is mass% with respect to the solid content of the copolymer when the slump value immediately after kneading is adjusted to 24 cm, and the smaller the amount added, the better the water reduction.
The retention was evaluated as follows by measuring the slump value 30 minutes after the measurement of the slump value immediately after kneading. The higher the score, the better the slump retention.
3 points: The slump value after 30 minutes is 90% or more of the slump value immediately after kneading 2 points: The slump value after 30 minutes is less than 90% of the slump value immediately after kneading, 70% or more 1 point: after 30 minutes A slump value of less than 70% of the slump value immediately after kneading The aqueous polymer solutions (P-1), (P-2), (P-3) and (P-4) of Examples were used as concrete admixtures. Time was excellent in both water reduction and retention.
On the other hand, when (H-1), (H-3) and (H-4) of Comparative Examples were used, the water reduction was good, but the retention was poor, and when (H-2) was used, the retention was Although the property was good, it was inferior in water reduction.

Claims (9)

A monomer comprising three or more monomers of an ethylene monomer (A) having a polyoxyalkylene group, an unsaturated organic acid monomer (B), and another unsaturated monomer (C) A cement admixture essentially comprising a copolymer obtained by polymerizing components,
The copolymer is obtained by changing the molar ratio of an ethylene monomer (A) having a polyoxyalkylene group and another unsaturated monomer (C) during polymerization. A cement admixture characterized in that a part of structural units in a coalescence can be hydrolyzed in an alkaline aqueous solution. The cement admixture according to claim 1, wherein the structural unit that can be hydrolyzed in the alkaline aqueous solution is a structural unit derived from the unsaturated monomer (C). The cement admixture according to claim 1 or 2, wherein the alkaline aqueous solution is an aqueous solution containing cement. The carboxyl group is generated by hydrolysis of a part of the monomer unit formed by the unsaturated monomer (C) in the copolymer. Cement admixture. The cement according to any one of claims 1 to 4, wherein the other unsaturated monomer (C) is a (meth) acrylic acid ester monomer and / or a maleic acid ester. Admixture. The copolymer is polymerized by dropping the other unsaturated monomer (C), and the dropping rate is changed during the polymerization of the other unsaturated monomer (C). The cement admixture according to any one of claims 1 to 5, wherein The copolymer is characterized in that the molar ratio between the ethylene monomer (A) having a polyoxyalkylene group and the unsaturated organic acid monomer (B) is constant during the polymerization. The cement admixture according to any one of claims 1 to 6. The cement admixture is an ethylene monomer (A) having a polyoxyalkylene group, an unsaturated organic acid monomer (B), and other unsaturated monomers (C) in a single amount. A copolymer obtained by polymerizing a monomer component containing a polymer, and two types of single monomers, an ethylene monomer (A) having a polyoxyalkylene group and an unsaturated organic acid monomer (B) The copolymer mixture containing at least three kinds of copolymers among the copolymers formed by polymerizing monomer components containing the polymer is essential. The cement admixture according to one. A cement composition comprising the cement admixture according to claim 1.