JP2011079721A - Early-strength cement admixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cement admixture which can provide a cement composition markedly excellent in dispersion performance (water reduction performance) and additionally early strength developability, and can remarkably improve productivity and workability; and to provide a cement composition containing the same. <P>SOLUTION: The cement admixture essentially comprises a polycarboxylic acid-based copolymer and an organic curing accelerator, wherein the polycarboxylic acid-based copolymer comprises a structural unit (A) originated from an unsaturated polyalkylene glycol ether-based monomer (a) represented by formula (1): YO(R<SP>1</SP>O)<SB>n</SB>R<SP>2</SP>, and a structural unit (B) originated from an unsaturated carboxylic acid-based monomer (b). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to the early strength cement admixture. More specifically, the present invention relates to a cement admixture and a cement composition that are useful as an additive component to cement compositions such as cement paste, mortar, and concrete.

Cement admixtures are widely used as additive components to cement compositions such as cement paste, mortar, and concrete, and are indispensable for building civil engineering and building structures from cement compositions. Yes. Such a cement admixture is used as a water reducing agent or the like, and has an effect of improving the strength, durability, and the like of the cured product by increasing the fluidity of the cement composition to reduce the cement composition. As a water reducing agent, a water reducing agent such as a naphthalene type has been conventionally used. However, a cement admixture containing a polycarboxylic acid polymer exhibits high water reducing performance as compared with this, so that it is a high performance AE water reducing agent. It has come to have a lot of actual use.

As such a cement admixture, recently, in addition to water reduction performance (dispersion performance) with respect to a cement composition, there has been a demand for a cement admixture that can improve the delay in hardening and develop strength at an early stage. For example, a concrete secondary product (precast) is made by pouring concrete into a formwork at a factory and then transporting it to the site to assemble it. However, this will improve productivity, increase work efficiency and save labor. For this purpose, it is required to be able to remove the mold from the mold at an early stage. Also, in the field of ready-mixed concrete, a cement admixture that develops strength at an early stage is required because it can be quickly transferred to the next step if it is hardened quickly after placing the concrete. However, the conventional cement admixture has a large degree of curing delay and cannot exhibit sufficient strength at the initial stage of curing.

Accordingly, a cement admixture containing a copolymer obtained by using an unsaturated (poly) alkylene glycol ether monomer and an unsaturated carboxylic acid monomer and a curing accelerator has been developed (Patent Document 1). 2), and the examples described in these patent documents specifically disclose a form in which an inorganic compound such as calcium nitrite or calcium chloride is used as a curing accelerator. A cement admixture containing a polycarboxylic acid copolymer obtained by using an unsaturated (poly) alkylene glycol ether monomer and an unsaturated carboxylic acid monomer and an alkanolamine compound has also been developed. (See Patent Document 3).

JP 2003-212623 A JP 2003-73158 A JP 2008-239416 A

As described above, various cement admixtures have been developed. In particular, the cement admixtures described in Patent Documents 1 to 3 are extremely useful in the industry, but further increase early strength development. Therefore, there was room for improvement in order to further improve productivity and workability.
The present invention has been made in view of the above situation, and can provide a cement composition that is remarkably excellent in early-stage strength development in addition to dispersion performance (water reduction performance), and greatly improves productivity and workability. It is an object of the present invention to provide a cement admixture that can be used and a cement composition containing the same.

The present inventors have made various studies on cement admixtures, and found that a copolymer obtained using an unsaturated polyalkylene glycol ether monomer having a polyalkylene glycol chain and an unsaturated carboxylic acid monomer is used. If included, the carboxyl group derived from the unsaturated carboxylic acid monomer has the action of adsorbing cement particles, and the polyalkylene glycol chain derived from the unsaturated polyalkylene glycol ether monomer is cement particles. First of all, attention was paid to the fact that it can exhibit high dispersion performance because it acts as a dispersing group for dispersing the. And as this unsaturated polyalkylene glycol ether monomer, if the polyalkylene glycol chain length is longer than 50, in addition to the dispersion performance (water reduction performance), early strength development, that is, the initial stage of curing ( For example, it is found that the compressive strength is particularly excellent after 1 to 7 days), and when the copolymer and the organic curing accelerator are used in combination, the synergistic effect causes the early strength to be significantly higher than expected. It was found to be improving and improving. In addition, as an organic curing accelerator, when using an amine curing accelerator, especially an alkanolamine compound, the inventors found that this effect is further exhibited, and conceived that the above problems can be solved brilliantly, The present invention has been achieved.

That is, the present invention is a cement admixture essentially comprising a polycarboxylic acid copolymer and an organic curing accelerator, and the polycarboxylic acid copolymer has the following general formula (1):
YO (R ¹ O) _n R ² (1)
(In the formula, Y represents an alkenyl group having 2 to 5 carbon atoms. R ¹ O is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. N represents R ¹ O. Represents an average number of added moles of the oxyalkylene group, and is a number exceeding 50 and not more than 300. R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. A cement admixture comprising a structural unit (A) derived from a saturated polyalkylene glycol ether monomer (a) and a structural unit (B) derived from an unsaturated carboxylic acid monomer (b).
The present invention is also a cement composition comprising the above cement admixture, cement and water.
The present invention is described in detail below.

(Cement admixture)
The cement admixture of the present invention may further contain one or more other components as long as the polycarboxylic acid copolymer and the organic curing accelerator are essential. Moreover, 1 type (s) or 2 or more types can each be used for a polycarboxylic acid type copolymer and an organic type hardening accelerator.
The content of the polycarboxylic acid copolymer in the cement admixture (when two or more polycarboxylic acid copolymers are included, the total content thereof) is not particularly limited. It is preferable that it is 20 mass% or more and 100 mass% or less in 100 mass% of solid content (namely, non-volatile content). More preferably, it is 40 mass% or more, More preferably, it is 50 mass% or more, Most preferably, it is 60 mass% or more.
In the present specification, “cement admixture” refers to a cement additive added to a cement composition such as cement paste, mortar, concrete, and the above-mentioned polycarboxylic acid copolymer and organic curing. It may be an agent consisting only of an accelerator, or may be an agent containing not only the polycarboxylic acid copolymer and the organic curing accelerator but also other components and additives as required. May be.

In the cement admixture, the content of the organic curing accelerator is preferably 50% by mass or less with respect to 100% by mass of the total amount of the polycarboxylic acid copolymer and the organic curing accelerator. . As a result, the water-reducing performance derived from the polycarboxylic acid copolymer can be exhibited, and the early strength development derived from both the polycarboxylic acid copolymer and the organic curing accelerator is synergized, and the action of the present invention. effect it is possible to more sufficiently exhibited. 45 wt% and more preferably less, even more preferably not more than 40 wt%. Moreover, it is preferable that it is 1 mass% or more, More preferably, it is 3 mass% or more, More preferably, it is 5 mass% or more, Most preferably, it is 10 mass% or more.

-Polycarboxylic acid copolymer-
In the cement admixture, the polycarboxylic acid copolymer is composed of a structural unit (A) derived from the unsaturated polyalkylene glycol ether monomer (a) represented by the general formula (1) and an unsaturated carboxylic acid. Although it contains the structural unit (B) derived from the acid monomer (b), it may further contain a structural unit (C) derived from another monomer (c) described later. Each structural unit may be one kind or two or more kinds.
Hereinafter, the unsaturated polyalkylene glycol ether monomer (a) is also referred to as “monomer (a)”, and “unsaturated carboxylic acid monomer (b)” is referred to as “monomer (b)”. Also called.

In the polycarboxylic acid-based copolymer, the proportion of the structural units (A) and (B) is preferably 1% by mass or more with respect to 100% by mass of all the structural units. If the structural unit (A) is less than 1% by mass, the early strength development may not be sufficiently exhibited, and if the structural unit (B) is less than 1% by mass, the polycarboxylic acid copolymer There is a possibility that the proportion of the carboxyl group present is too small to exhibit sufficient dispersibility. The content ratio of the structural unit (A) in the total amount of the structural units (A) and (B) of 100% by mass is preferably 60 to 96% by mass, more preferably 70 to 95% by mass, and still more preferably 80%. It is -94 mass%, Most preferably, it is 84-94 mass%. Moreover, as a content rate of the structural unit (B) which occupies in 100 mass% of total amount of a structural unit (A) and (B), Preferably it is 4-60 mass%, More preferably, it is 5-30 mass%, More preferably, Is 6 to 20% by mass, particularly preferably 6 to 16% by mass.
By setting it in the above range, it is possible to further develop the effect of the present invention that the fluidity retention performance can be remarkably exhibited simultaneously with the early strength development performance and water reduction performance.

Further, the total ratio (mass%) of the structural units (A) and (B) is preferably 70 to 100 mass% with respect to 100 mass% of all the structural units. That is, it is preferable that the content rate of the structural unit (C) derived from another monomer (c) is 0-30 mass% with respect to 100 mass% of all the structural units. The total ratio of the structural units (A) and (B) in 100% by mass of all the structural units is more preferably 80 to 100% by mass, still more preferably 90 to 100% by mass, and particularly preferably 95 to 100% by mass. .

Here, in this specification, when calculating the ratio of the structural unit (B) derived from the unsaturated carboxylic acid monomer (b), the structural unit (B) is a completely neutralized single monomer. It shall be calculated as a structural unit derived from the body (salt). For example, when acrylic acid is used as the monomer (b) and neutralized with sodium hydroxide in the polymerization reaction, sodium acrylate is used as the monomer (b). ).

In the polycarboxylic acid copolymer, the proportion of the structural unit (A) is preferably 50 mol% or less with respect to 100 mol% of all the structural units. This is because the unsaturated polyalkylene glycol ether monomer (a) constituting the structural unit (A) is not sufficiently polymerizable, and a highly dispersible polycarboxylic acid copolymer is obtained in a high yield. Furthermore, it is because it is preferable that the use ratio of the monomer (a) is 50 mol% or less with respect to 100 mol% of all monomer components. More preferably, it is 48 mol% or less.

Next, the monomer component constituting the polycarboxylic acid copolymer will be further described. In addition, each monomer can use 1 type (s) or 2 or more types, respectively.
<Unsaturated polyalkylene glycol ether monomer (a)>
The monomer (a) is a monomer represented by the above general formula (1), and the structural unit (A) derived from the monomer (a) is a monomer (a). Means a structure in which the unsaturated double bond (carbon-carbon double bond) portion of the is a single bond.
In the general formula (1), R ¹ O represents an oxyalkylene group having 2 to 18 carbon atoms. Among them, an oxyalkylene group having 2 to 8 carbon atoms is preferable, and examples thereof include an oxyethylene group, an oxypropylene group, an oxybutylene group, an oxyisobutylene group, an oxymethylethylene group, an oxyoctylene group, and an oxystyrene group. An oxyalkylene group having 2 to 4 carbon atoms is more preferable, and an oxyethylene group is particularly preferable. The polyalkylene glycol chain represented by (R ¹ O) _n may be formed by two or more oxyalkylene groups. In this case, two or more oxyalkylene groups are randomly added. Any addition form such as block addition or alternate addition may be used.

In the general formula (1), the ratio of oxyethylene groups in 100 mol% of all oxyalkylene groups is preferably 50 mol% or more. Thereby, sufficient dispersibility can be exhibited. More preferably 70 mol% or more, still more preferably 80 mol% or more, particularly preferably 90 mol% or more, most preferably 100 mol%, that is, a polyalkylene represented by (R ¹ O) n only by an oxyethylene group A glycol chain is formed. In addition, as the combination having two or more oxyalkylene groups, (oxyethylene group, oxypropylene group), (oxyethylene group, oxybutylene group), (oxyethylene group, oxystyrene group) are preferable. . Among these, (oxyethylene group, oxypropylene group) is more preferable.

The average addition mole number (average chain length of the polyalkylene glycol chain) n of the oxyalkylene group is more than 50 and 300 or less. Thus, by having a long polyalkylene glycol chain where n is greater than 50, the polycarboxylic acid copolymer can sufficiently exhibit early strength development, and when used in combination with an organic curing accelerator, cure delay Can be further improved significantly. From the viewpoint of early strength development performance and dispersion performance, the lower limit value of n is preferably not less than a specific value in the following order (preferably in order of increasing next numerical value). That is, 60 or more, 75 or more, 100 or more, 110 or more, 120 or more, 130 or more are preferable. On the other hand, if n exceeds 300, the copolymerizability may not be sufficient, and the dispersibility retention performance may not be fully exhibited. Therefore, the upper limit value of n is preferably equal to or less than a specific value in the following order (preferably in the order of decreasing the next numerical value). That is, 280 or less, 250 or less, 225 or less, 200 or less, 180 or less, 170 or less, 160 or less are preferable.
The average chain length of polyalkylene glycol chain (average added mole number of oxyalkylene group) is a polyalkylene derived from the polyalkylene glycol ether monomer (a) possessed by the polycarboxylic acid copolymer. It means the average number of moles of oxyalkylene groups added to 1 mole of glycol chain.

In the general formula (1), R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. However, as the number of carbon atoms in the hydrocarbon group increases, the hydrophobicity increases and the dispersibility is sufficient. Therefore, the number of carbon atoms in the hydrocarbon group is preferably 1-20. More preferably, it is 1-12, More preferably, it is 1-10, Most preferably, it is 1-6, Most preferably, it is 1-4.
As the hydrocarbon group, for example, an alkyl group (straight chain, branched chain or cyclic), a phenyl group, an alkyl-substituted phenyl group, an alkenyl group, an alkynyl group, an aryl and the like are preferable. Of these, an alkyl group (straight chain, branched chain or cyclic) is preferable.
R ² is particularly preferably a hydrogen atom, a methyl group or an ethyl group.

In the general formula (1), Y represents an alkenyl group having 2 to 5 carbon atoms, for example, an alkenyl group having 2 carbon atoms such as a vinyl group; an alkenyl group having 3 carbon atoms such as an allyl group; Group, alkenyl group having 4 carbon atoms such as 3-butenyl group, 2-butenyl group, 1-methyl-2-propenyl group; 3-methyl-3-butenyl group, 4-pentenyl group, 3-pentenyl group, 2 -Methyl-2-butenyl group, 2-methyl-3-butenyl group, 1,1-dimethyl-2-propenyl group and the like are preferable. Among these, an alkenyl group having 4 to 5 carbon atoms is preferable, and a methallyl group and a 3-methyl-3-butenyl group are more preferable.

The unsaturated polyalkylene glycol ether monomer (a) can be obtained, for example, by addition reaction of unsaturated glycol with alkylene glycol (alkylene oxide). The unsaturated alcohol is not particularly limited as long as it has a group having an unsaturated bond and a hydroxyl group, but preferably has a group having a double bond and a hydroxyl group. What has one each is more preferable. More preferably, the unsaturated alcohol is represented by the following general formula (2):
YO— (R ¹ O) _p —H (2)
(In the formula, Y corresponds to Y described above. P represents the average number of added moles of the oxyalkylene group represented by R ¹ O, and is a number from 0 to 300. R ¹ O represents R above. ^{It is the same as 1} O.).

In the said General formula (2), although p is a number of 0-300, as a range of p, 0-200 are preferable. More preferably, it is 0-100, More preferably, it is 0-50, More preferably, it is 0-25, Especially preferably, it is 0-10, Most preferably, it is 0-4. Also, p is, it is preferable is 1 or more. If p is equal to or greater than 1, 1 to 50 it is preferable. More preferably, it is 1-25, More preferably, it is 1-10, More preferably, it is 1-5, More preferably, it is 1-3, Most preferably, it is 1-2, Most preferably, it is 1. Furthermore, p is also suitable if 0. When p is 0, in the compound represented by the general formula (2), Y corresponds to an unsaturated alcohol having 2 to 5 carbon atoms.

Specific examples of the unsaturated alcohol include, for example, alcohols such as methallyl alcohol, allyl alcohol, and 3-methyl-3-buten-1-ol, and alkylene oxide adducts of these alcohols. As the adduct, those having a relatively small average added mole number p are preferable.
Among the above unsaturated alcohols, methallyl alcohol, allyl alcohol, 3-methyl-3-buten-1-ol, methallyl alcohol-1EO (one mole of ethylene oxide added to methallyl alcohol), allyl alcohol-1EO (One mole of ethylene oxide added to allyl alcohol), 3-methyl-3-buten-1-ol-1EO (one mole of ethylene oxide added to 3-methyl-3-buten-1-ol), Methallyl alcohol-2EO (two moles of ethylene oxide added to methallyl alcohol), allyl alcohol-2EO (two moles of ethylene oxide added to allyl alcohol), 3-methyl-3-buten-1-ol- 2EO (3-methyl-3-buten-1-ol and ethylene Kisaido 2 mol addition to ones) are more preferable.

As said alkylene oxide, a C2-C18 alkylene oxide is preferable. More preferably, it is C2-C8 alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide, isobutylene oxide, styrene oxide, etc. are mentioned. Among these, alkylene oxides having 2 to 4 carbon atoms are preferable, and ethylene oxide is particularly preferable. Two or more kinds of alkylene oxides may be used. In this case, the addition reaction may be in any form such as random addition, block addition, and alternate addition.

Specific examples of the unsaturated polyalkylene glycol ether monomer (a) include, for example, vinyl alcohol alkylene oxide adducts, (meth) allyl alcohol alkylene oxide adducts, and 3-buten-1-ol alkylene oxide adducts. , Isoprenyl 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 adducts, 2-methyl-2-buten-1-ol alkylene oxide adducts, 2-methyl-3-buten-1-ol alkylene oxide adducts, and the like are suitable.

More specifically, for example, methoxy polyethylene glycol monomethallyl ether, ethoxy polyethylene glycol monomethallyl ether, propoxy polyethylene glycol monomethallyl ether, butoxy polyethylene glycol monomethallyl ether, phenoxy polyethylene glycol monomethallyl ether, polyethylene glycol monovinyl ether, polyethylene glycol Monoallyl ether, polyethylene glycol monomethallyl 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, poly Tylene 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 mono (3 -Methyl-3-butenyl) ether, methoxypolyethylene glycol mono (3-methyl-3-butenyl) ether, ethoxypolyethyleneglycol mono (3-methyl-3-butenyl) ether, 1-propoxypolyethyleneglycolmono (3-methyl- 3-butenyl) ether, cyclohexyloxypolyethylene glycol mono (3-methyl-3-butenyl) ether, phenoxypolyethyleneglycol mono (3-methyl-3-butenyl) ether, methoxypoly Tylene glycol monoallyl ether, ethoxy polyethylene glycol monoallyl ether, phenoxy polyethylene glycol monoallyl ether, methoxy polyethylene glycol mono (2-methyl-2-propenyl) ether, ethoxy polyethylene glycol mono (2-methyl-2-propenyl) ether, Phenoxy polyethylene glycol mono (2-methyl-2-propenyl) ether and the like are preferable.

<Unsaturated carboxylic acid monomer (b)>
The monomer (b) is a monomer containing an unsaturated double bond (carbon-carbon double bond) and a carboxyl group and / or a carboxylate. The structural unit (B) derived from the unsaturated carboxylic acid monomer (b) means a structure in which the unsaturated double bond portion of the monomer (b) is a single bond.

Here, including a carboxyl group and / or a carboxylate salt means that a group represented by —COOZ (Z represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group) is 1 per molecule. It means having one or more. Examples of metal atoms include alkali metals such as sodium, lithium, potassium, rubidium and cesium; alkaline earth metals such as magnesium, calcium, strontium and barium; aluminum and iron. Organic amine groups include monoethanolamine groups, diethanolamine groups, triethanolamine groups and other alkanolamine groups; monoethylamine groups, diethylamine groups, triethylamine groups and other alkylamine groups; ethylenediamine groups, triethylenediamine groups and other polyamines Groups and the like. Among these, the carboxylate is preferably an ammonium salt, a sodium salt, or a potassium salt, and more preferably a sodium salt.

The unsaturated carboxylic acid monomer (b) includes an unsaturated monocarboxylic acid monomer containing an unsaturated double bond and one carboxyl group or carboxylate in one molecule, An unsaturated dicarboxylic acid monomer containing an unsaturated double bond and two carboxyl groups or a carboxylate is preferable.

Specific examples of the unsaturated monocarboxylic acid monomer include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, α-hydroxyacrylic acid, α-hydroxymethylacrylic acid and derivatives thereof, These salts are mentioned.
Specific examples of the unsaturated dicarboxylic acid monomer include unsaturated dicarboxylic acids such as maleic acid, itaconic acid, citraconic acid, fumaric acid, and mesaconic acid, salts thereof, and anhydrides thereof. Can be mentioned.
Among these, acrylic acid, acrylate, maleic acid, maleic anhydride, fumaric acid and salts thereof are preferable from the viewpoint of polymerizability. Of these, acrylic acid, methacrylic acid, and salts thereof are more preferable. That is, the carboxylic acid monomer (b) preferably includes (meth) acrylic acid or a salt thereof. More preferably, it is acrylic acid or a salt thereof, and by including a structure derived from acrylic acid or a salt thereof, the resulting polycarboxylic acid copolymer can exhibit further superior dispersibility in a smaller amount. Become.
Acrylic acid and methacrylic acid are collectively referred to as “(meth) acrylic acid”.

<Other monomer (c)>
As described above, the polycarboxylic acid copolymer also contains the structural unit (C) derived from the monomer (c) other than the essential monomer components (a) and (b). It may be included. Such a monomer (c) may be any monomer that can be copolymerized with the monomer (a) and / or (b), and includes, for example, one or more of the following compounds. Can be used.
Half esters and diesters of the above unsaturated dicarboxylic acid monomers and alcohols having 1 to 30 carbon atoms; Half amides and diamides of the above unsaturated dicarboxylic acid monomers 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 an alkylene oxide having 2 to 18 carbon atoms to the alcohol or amine and the unsaturated dicarboxylic acid monomer; Half esters and diesters of saturated dicarboxylic dicarboxylic acid monomers and alkylene glycols having 2 to 18 carbon atoms or polyalkylene glycols having 2 to 500 addition moles of the alkylene glycol; methyl (meth) acrylate, ethyl (meta ) Acrylate, propyl (meth) acrylate, glycidyl Esters of unsaturated monocarboxylic acids such as (meth) acrylate, methyl crotonate, ethyl crotonate, propyl crotonate and alcohols having 1 to 30 carbon atoms; alcohols having 1 to 30 carbon atoms and 2 to 18 carbon atoms Esters of alkoxy (poly) alkylene glycols to which 1 to 500 moles of alkylene oxide have been added and unsaturated monocarboxylic acids such as (meth) acrylic acid; (poly) ethylene glycol monomethacrylate, (poly) propylene glycol monomethacrylate, 1-500 molar adducts of alkylene oxides having 2-18 carbon atoms to unsaturated monocarboxylic acids such as (meth) acrylic acid, such as (poly) butylene glycol monomethacrylate;

Half amides of maleamic acid and glycols having 2 to 18 carbon atoms or polyalkylene glycols having 2 to 500 addition moles of these glycols; hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tri Polyfunctional (meth) acrylates such as methylolpropane di (meth) acrylate; (poly) alkylene glycol dimaleates such as triethylene glycol dimaleate and polyethylene glycol dimaleate; vinyl sulfonate, (meth) allyl sulfonate, 2- ( (Meth) acryloxyethyl sulfonate, 3- (meth) acryloxypropyl sulfonate, 3- (meth) acryloxy-2-hydroxypropyl sulfonate, 3- (meth) acryloxy-2-hydroxypropyls Phophenyl ether, 3- (meth) acryloxy-2-hydroxypropyloxysulfobenzoate, 4- (meth) acryloxybutyl sulfonate, (meth) acrylamidomethylsulfonic acid, (meth) acrylamidoethylsulfonic acid, 2-methylpropanesulfone Unsaturated sulfonic acids such as acid (meth) acrylamide and styrene sulfonic acid, and monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts thereof; unsaturated monocarboxylic acids such as methyl (meth) acrylamide and carbon atom Amides with amines of 1 to 30; Vinyl aromatics such as styrene, α-methylstyrene, vinyltoluene, p-methylstyrene;

Dienes such as butadiene, isoprene, 2-methyl-1,3-butadiene, 2-chloro-1,3-butadiene; (meth) acrylamide, (meth) acrylalkylamide, N-methylol (meth) acrylamide, N, Unsaturated amides such as N-dimethyl (meth) acrylamide; unsaturated cyanides such as (meth) acrylonitrile and α-chloroacrylonitrile; unsaturated esters such as vinyl acetate and vinyl propionate; aminoethyl (meth) acrylate , Unsaturated amines such as methylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dibutylaminoethyl (meth) acrylate, vinylpyridine, and the like; divinyl aromatics; such as triallyl cyanurate Anurates; Allyls such as (meth) allyl alcohol and glycidyl (meth) allyl ether; Unsaturated amino compounds such as dimethylaminoethyl (meth) acrylate; Methoxypolyethylene glycol monovinyl ether, Polyethylene glycol monovinyl ether, Methoxypolyethylene glycol mono Vinyl ethers or allyl ethers such as (meth) allyl ether and polyethylene glycol mono (meth) allyl ether; polydimethylsiloxanepropylaminomaleamic acid, polydimethylsiloxaneaminopropylaminomaleamic acid, polydimethylsiloxane-bis- (propylamino) Maleamic acid), polydimethylsiloxane-bis- (dipropyleneamino maleamic acid), polydimethylsiloxane- (1-propyl-3-acrylate), polydimethylsiloxane- (1-propyl-3-methacrylate), polydimethylsiloxane-bis- (1-propyl-3-acrylate), polydimethylsiloxane-bis- (1-propyl) (3-methacrylate) and the like, and one or more of these can be used.

Next, a method for obtaining the polycarboxylic acid copolymer will be described.
As a method for obtaining the polycarboxylic acid-based copolymer, a monomer containing monomer (a) and monomer (b) and, if necessary, monomer (c) is used by using a polymerization initiator. The monomer component may be copolymerized, but the type and amount of the monomer contained in the monomer component are set so that the structural unit constituting the polycarboxylic acid copolymer is within the above-described range. It is preferable to set appropriately. That is, it is preferable to appropriately set the type and amount of the monomer contained in the monomer component so that the proportion of the structural units constituting the polycarboxylic acid copolymer is in the preferred range described above. .

Therefore, the content of each of the monomers (a) and (b) is 1% by mass or more with respect to 100% by mass of all monomer components used to obtain the polycarboxylic acid copolymer. Is preferred. Further, the content ratio of the monomer (a) in the total amount of 100% by mass of the monomers (a) and (b) is preferably 60 to 96% by mass, more preferably 70 to 95% by mass, Especially preferably, it is 80-94 mass%, Most preferably, it is 94-94 mass%. Moreover, as a content rate of the monomer (b) which occupies in 100 mass% of total amounts of monomer (a) and (b), Preferably it is 4-60 mass%, More preferably, 5-30 mass%, More preferably, it is 6-20 mass%, Most preferably, it is 6-16 mass%.

The total ratio (mass%) of the monomers (a) and (b) is preferably 70 to 100 mass% with respect to 100 mass% of all monomer components. That is, it is preferable that the content rate of another monomer (c) is 0-30 mass% with respect to 100 mass% of all the monomer components. The total ratio of the monomers (a) and (b) in 100% by mass of all monomer components is more preferably 80 to 100% by mass, still more preferably 90 to 100% by mass, and particularly preferably 95 to 100% by mass. %.
In order to obtain a highly dispersible polycarboxylic acid copolymer in a high yield, the proportion of the monomer (a) is 50 mol% or less with respect to 100 mol% of all monomer components. Is preferred. More preferably, it is 48 mol% or less.

The copolymerization can be performed by a usual method such as solution polymerization or bulk polymerization. The solution polymerization can be carried out either batchwise or continuously. Examples of the solvent used here include water; alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol; benzene, toluene, xylene, cyclohexane, n- Examples include aromatic or aliphatic hydrocarbons such as hexane; ester compounds such as ethyl acetate; ketone compounds such as acetone and methyl ethyl ketone; and cyclic ether compounds such as tetrahydrofuran and dioxane. Among these, from the viewpoint of the solubility of the raw material monomer and the resulting polymer, it is preferable to use at least one selected from the group consisting of water and a lower alcohol having 1 to 4 carbon atoms. It is more preferable in that the solvent step can be omitted.

When the copolymerization is performed by an aqueous solution polymerization method, a water-soluble polymerization initiator, for example, a persulfate such as ammonium persulfate, sodium persulfate, or potassium persulfate; hydrogen peroxide; 2 Azoamidine compounds such as 2,2′-azobis-2-methylpropionamidine hydrochloride, cyclic azoamidine compounds such as 2,2′-azobis-2- (2-imidazolin-2-yl) propane hydrochloride, 2-carbamoylazoiso It is preferable to use a water-soluble azo initiator such as an azonitrile compound such as butyronitrile. In addition, at this time, alkali metal sulfites such as sodium hydrogen sulfite, metabisulfite, sodium hypophosphite, Fe (II) salts such as molle salt, sodium hydroxymethanesulfinate dihydrate, hydroxylamine hydrochloride, Accelerators such as thiourea, L-ascorbic acid (salt), and erythorbic acid (salt) can also be used in combination. Among these, a combination of hydrogen peroxide and an accelerator such as L-ascorbic acid (salt) is preferable. These radical polymerization initiators and accelerators may be used alone or in combination of two or more.

In the copolymerization, the reaction temperature is not particularly limited. For example, when persulfate is used as the initiator, the reaction temperature is preferably in the range of 30 to 100 ° C, more preferably in the range of 40 to 95 ° C, and 45 to 45 ° C. A range of 90 ° C. is more preferable. Further, when hydrogen peroxide and L-ascorbic acid (salt) as a promoter are combined to form an initiator, the reaction temperature is preferably in the range of 30 to 100 ° C, more preferably in the range of 40 to 95 ° C, and 45 to 45 ° C. A range of 90 ° C. is more preferable.
Although the polymerization time in the case of copolymerization is not specifically limited, For example, the range of 0.5 to 10 hours is preferable. If the polymerization time is too long or too short than this range, the polymerization rate may be lowered or the productivity may be lowered, which is not preferable. More preferably, it is 0.5-8 hours, More preferably, it is the range of 1-6 hours.
The amount of all monomer components used in the copolymerization is preferably in the range of 10 to 99% by mass with respect to 100% by mass of all the raw materials including other raw materials and the polymerization solvent. In particular, if the amount of all the monomer components used is too lower than this range, it is not preferred because it may cause a decrease in polymerization rate or a decrease in productivity. More preferably, it is 20-98 mass%, More preferably, it is 25-95 mass%, More preferably, it is 30-90 mass%, Especially preferably, it is 30-80 mass%, Most preferably, it is the range of 40-70 mass%.

In the above copolymerization, the method for charging each monomer component into the reaction vessel is not particularly limited, a method in which the entire amount is initially charged into the reaction vessel; a method in which the entire amount is divided or continuously charged into the reaction vessel; Examples thereof include a method of initially charging the reaction vessel and dividing or continuously charging the remainder into the reaction vessel. In addition, by changing the charging rate of each monomer into the reaction vessel during the reaction continuously or stepwise, and changing the weight ratio of each monomer per unit time continuously or stepwise, Two or more types of copolymers having different monomer ratios may be synthesized simultaneously during the polymerization reaction. The radical polymerization initiator may be charged into the reaction vessel from the beginning, may be dropped into the reaction vessel, or may be combined according to the purpose.

In the copolymerization, a chain transfer agent can be used for adjusting the molecular weight of the resulting polycarboxylic acid copolymer. In particular, it is preferable to use a chain transfer agent when the polymerization reaction is performed at a high concentration of 30% by mass or more with respect to 100% by mass of the total amount of raw materials used during polymerization. . Examples of chain transfer agents include mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycolate, octyl 3-mercaptopropionate, 2-mercaptoethanesulfonic acid, etc. These thiol chain transfer agents can be used, and two or more types of chain transfer agents can be used in combination. Furthermore, in order to adjust the molecular weight of the copolymer, it is also effective to use a monomer having high chain mobility such as (meth) allylsulfonic acid (salt) as the monomer (c).

In the above copolymerization reaction, when a solvent is used, the polymerization may be carried out at a pH of 5 or more, but in that case, the polymerization rate is lowered and the copolymerizability is not sufficient, and the performance as a cement admixture. Therefore, it is preferable to carry out the copolymerization reaction at a pH of less than 5. The adjustment of pH may be performed by, for example, non-polymerizable organic sulfonic acid having a molecular weight of 300 or less and / or a salt thereof, an inorganic salt such as a monovalent metal or divalent metal hydroxide or carbonate; ammonia, an organic amine, etc. Alkaline material substance: It can be performed using a pH adjuster such as inorganic acids such as hydrochloric acid, phosphoric acid, and sulfuric acid. These pH adjusters can use 1 type (s) or 2 or more types.

In the copolymerization reaction, it is particularly preferable to control (adjust) the pH during the copolymerization by using essentially non-polymerizable organic sulfonic acid having a molecular weight of 300 or less and / or a salt thereof. That is, in the copolymerization reaction, it is preferable to control the pH during copolymerization in the presence of a pH adjuster containing a non-polymerizable organic sulfonic acid having a molecular weight of 300 or less and / or a salt thereof. More preferably, the copolymerization is carried out by controlling the pH during the copolymerization to 3 or less, and this makes it easier to obtain a sufficient copolymerizability for the unsaturated polyalkylene glycol ether monomer (a). The production cost of the polycarboxylic acid copolymer to be produced can be reduced, and the cement admixture can have a higher performance. More preferably, the copolymerization is carried out by controlling the pH to 2 to 3.

Examples of the non-polymerizable organic sulfonic acid and / or salt thereof include, for example, the following general formula (5):
_{^{R 10 - (Ph) m-}} SO 3 H (5)
(Wherein R ¹⁰ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, Ph represents a phenyl group, m represents 0 or 1), and It is preferable that the salt is an organic sulfonic acid salt represented by the general formula (5).
The salt is not particularly limited, and examples thereof include metal salts, ammonium salts, and organic amine salts (organic ammonium salts). The metal atom constituting the metal salt is preferably an alkali metal such as sodium, lithium, potassium, rubidium or cesium; an alkaline earth metal such as magnesium, calcium, strontium or barium; aluminum or iron. Organic amine salts include alkanolamine salts such as monoethanolamine salts, diethanolamine salts and triethanolamine salts; alkylamine salts such as monoethylamine salts, diethylamine salts and triethylamine salts; polyamine salts such as ethylenediamine salts and triethylenediamine salts Is preferred.

In the general formula (5), R ¹⁰ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and particularly preferably an alkyl group having 1 or 2 carbon atoms. Specifically, a methyl group and an ethyl group are preferable, but by using an organic sulfonic acid and / or a salt thereof in which R ¹⁰ is an alkyl group having 1 or 2 carbon atoms, the cement admixture of the present invention can be dispersed. The property can be further improved.

The non-polymerizable organic sulfonic acid and / or salt thereof is preferably a low molecular weight compound having a molecular weight of 300 or less. However, in order to further develop the effect of exhibiting a sufficient dispersibility, the molecular weight is 250. The following is more preferable. More preferably, the molecular weight is 200 or less.

Specifically, as the non-polymerizable organic sulfonic acid having a molecular weight of 300 or less and / or a salt thereof, for example, paratoluenesulfonic acid and / or a hydrate thereof, methanesulfonic acid and / or a salt thereof, and the like are preferable. .

In the above pH adjuster, the proportion of non-polymerizable organic sulfonic acid and / or salt thereof used is 50% by mass of non-polymerizable organic sulfonic acid and / or salt thereof relative to 100% by mass of the total amount of pH adjuster. % Or more is preferred. More preferably, it is 70 mass% or more, More preferably, it is 90 mass% or more.
The amount of the non-polymerizable organic sulfonic acid and / or salt thereof used is preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the total amount of monomer components. If the amount of the non-polymerizable organic sulfonic acid and / or salt thereof used is too large, the pH during the copolymerization will be too low, and there is a possibility that preferable polymerization conditions will not be achieved. More preferably, it is 0.05-4 weight part, More preferably, it is 0.05-2.5 weight part.
In addition, the ratio of the usage-amount of the pH adjuster with respect to 100 weight part of total amounts of said monomer component is substantially the content rate (weight) of the pH adjuster with respect to 100 weight part of copolymers in the composition obtained. Part).

The polycarboxylic acid-based copolymer can be used as it is as a main component of a cement admixture, but it is preferable to adjust the pH to 5 or more from the viewpoint of handleability. As described above, the copolymerization reaction is preferably performed at a pH of less than 5, and the pH is preferably adjusted to 5 or more after the copolymerization. The pH can be adjusted using, for example, an alkaline substance such as inorganic salt such as hydroxide or carbonate of monovalent metal or divalent metal; ammonia; organic amine; It is also possible to carry out after the completion of the reaction, the concentration adjustment if necessary. The polycarboxylic acid copolymer may be used as a main component of the cement admixture as it is in the form of an aqueous solution, or may be neutralized with a hydroxide of a divalent metal such as calcium or magnesium. It may be used after being made into a polyvalent metal salt and then dried, or supported on an inorganic powder such as silica fine powder and dried.

As the weight average molecular weight (Mw) of the polycarboxylic acid copolymer, it is preferable that the weight average molecular weight (Mw) is 500,000 or less in consideration of the handleability, the retention of the cement composition, and the like. . More preferably, it is 300,000 or less, More preferably, it is 200,000 or less, Most preferably, it is 100,000 or less. Moreover, it is preferable that Mw is 3000 or more from the viewpoint that adsorbing to cement particles to some extent tends to exhibit performance, and that the adsorption power increases as Mw increases. More preferably, it is 5000 or more, More preferably, it is 7000 or more, Especially preferably, it is 10,000 or more, Most preferably, it is 20,000 or more.
In addition, the weight average molecular weight of the said polycarboxylic acid type-copolymer can be calculated | required by the gel permeation chromatography (GPC) analysis method mentioned later.

-Organic curing accelerator-
The organic curing accelerator is a curing accelerator for organic compounds, and examples thereof include amine compounds, calcium organic acids such as calcium formate and calcium acetate, and the like, one or more of these. Can be used. Of these, amine compounds are preferred. Examples of the amine compound include alkanolamine compounds such as trialkanolamine compounds and tetraalkanolamine compounds. Among these, alkanolamine compounds are preferable, and among the alkanolamine compounds, trialkanol. Amine compounds and tetraalkanolamine compounds are particularly preferred. By using these, it becomes possible to further enhance early strength development. Thus, a form in which the alkanolamine compound is at least one selected from the group consisting of a trialkanolamine compound and a tetraalkanolamine compound is also a preferred form of the present invention.

Examples of the trialkanolamine compound include the following general formula (3):

(Wherein R ³ , R ⁴ and R ⁵ are the same or different and represent a divalent alkylene group having 1 to 20 carbon atoms or a divalent arylene group having 6 to 20 carbon atoms). Compounds are preferably used. Specific examples of such compounds include triethanolamine, hydroxyethyl di- (hydroxypropyl) -amine, di- (hydroxyethyl) -hydroxypropylamine, tri- (hydroxypropyl) -amine, hydroxyethyl -(Hydroxy-n-butyl) -amine, tri- (2-hydroxybutyl) -amine, hydroxybutyl di- (hydroxypropyl) -amine, triisopropanolamine, N, N-bis- (2-hydroxybutyl)- N- (2-hydroxypropyl) -amine and the like. Among these, triethanolamine represented by the following formula (3-1) and triisopropanolamine represented by the following formula (3-2) are particularly suitable.

Examples of the tetraalkanolamine compound include the following general formula (4):

(Wherein R ⁶ , R ⁷ , R ⁸ and R ⁹ are the same or different and each represents a divalent alkylene group having 1 to 20 carbon atoms or a divalent arylene group having 6 to 20 carbon atoms). The compounds represented are preferably used. Specifically, for example, tetraethanolamine represented by the following formula (4-1) and tetraisopropanolamine represented by the formula (4-2) are preferable.

As said organic type hardening accelerator, 1 type (s) or 2 or more types, such as a compound mentioned above, can be used, However, It is especially suitable to use 2 or more types of organic hardening accelerators especially. This can increase the early strength development even more. More preferably, two or more alkanolamine compounds are used, and more preferably, at least two or more selected from the group consisting of trialkanolamine compounds and tetraalkanolamine compounds are used.

-Other ingredients-
The cement admixture of the present invention preferably further contains a non-polymerizable organic sulfonic acid having a molecular weight of 300 or less and / or a salt thereof. Thereby, the dispersibility can be more fully exhibited. In such a cement admixture, the polymerization of the monomer component in obtaining the polycarboxylic acid copolymer is performed in the presence of a non-polymerizable organic sulfonic acid having a molecular weight of 300 or less and / or a salt thereof. Can be obtained.
In addition, the preferable form of the non-polymerizable organic sulfonic acid having a molecular weight of 300 or less and / or a salt thereof is as described above.

The content of the non-polymerizable organic sulfonic acid having a molecular weight of 300 or less and / or a salt thereof is 0.01 to 5 weights with respect to 100 parts by weight of the polycarboxylic acid copolymer contained in the cement admixture. Part. As a result, the effect exhibited by the non-polymerizable organic sulfonic acid having a molecular weight of 300 or less and / or its salt is synergized with the effect exhibited by the polycarboxylic acid copolymer and the organic curing accelerator. it is possible to obtain a cement admixture having a performance. More preferably, it is 0.05-4 weight part, More preferably, it is 0.05-2.5 weight part.

The cement admixture of the present invention preferably further contains a polyalkylene glycol. The content of the polyalkylene glycol is preferably 1 to 50 parts by weight with respect to 100 parts by weight of the polycarboxylic acid copolymer. By further containing polyalkylene glycol, the workability of the cement composition such as mortar and concrete can be further improved, but if it is less than 1 part by weight, this workability improvement effect will not be more sufficient. If it exceeds 50 parts by weight, the dispersibility with respect to cement may not be improved. More preferably, it is 2-50 weight part, More preferably, it is 2-40 weight part, Most preferably, it is 3-30 weight part.

The cement admixture also includes viscosity (workability, for example, mortar) in addition to fluidity (ease of flow when poured) and early strength development due to the inclusion of the polycarboxylic acid copolymer. It is also possible to improve the ease of kneading and scoop work at the concrete site.

The cement admixture may further contain other commonly used cement dispersants and can be used in combination. Other cement dispersants are not particularly limited. For example, various sulfonic acid dispersants having a sulfonic acid group in the molecule, and various polycarboxylic acid dispersants having a polyoxyalkylene chain and a carboxyl group in the molecule. Etc. Further, for example, one or more of cement additives (materials) exemplified in the following (1) to (21) may be included. The blending ratio of these cement dispersant and cement additive (material) may be set so that the total amount is 10 parts by weight or less with respect to 100 parts by weight of the solid content of the polycarboxylic acid copolymer. Is preferred.

(1) Water-soluble polymer substances: polyacrylic acid (sodium), polymethacrylic acid (sodium), polymaleic acid (sodium), unsaturated carboxylic acid polymer such as sodium salt of acrylic acid / maleic acid copolymer; polyethylene Polyoxyethylene or polyoxypropylene polymers such as glycol and polypropylene glycol, or copolymers thereof.

(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. Acid 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; alumina cement; calcium aluminate silicate and the like.
(5) Mineral oil-based antifoaming agent: cocoon oil, liquid paraffin, etc.
(6) Fat and oil-based antifoaming agents: animal and vegetable oils, sesame oil, castor oil, these alkylene oxide adducts and the like.
(7) Fatty acid-based antifoaming agent: oleic acid, stearic acid, and these alkylene oxide adducts.
(8) Fatty acid ester antifoaming agent: glycerin monoricinoleate, alkenyl succinic acid derivative, sorbitol monolaurate, sorbitol trioleate, natural wax and the like.

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

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

(16) Other surfactants: various anionic surfactants; various cationic surfactants; various nonionic 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.
(21) Cement additives (materials) other than the above (1) to (20); cement wetting agent, thickener, separation reducing agent, flocculant, drying shrinkage reducing agent, strength enhancer, self-leveling agent, rust prevention Agents, coloring agents, fungicides, blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica fume, silica powder, plaster and the like.

The cement admixture can be used for various hydraulic materials, that is, cement compositions such as cement and gypsum, and other hydraulic materials. As a specific example of a hydraulic composition containing such a hydraulic material, water and the above cement admixture, and further containing fine aggregate (sand, etc.) and coarse aggregate (crushed stone, etc.) as necessary, Cement paste, mortar, concrete, plaster, etc. are mentioned. Among these hydraulic compositions, a cement composition using cement as the hydraulic material is most preferable, and a cement composition containing the cement admixture, cement, and water as essential components is also one aspect of the present invention. .

(Cement composition)
In the above cement composition, as the cement, Portland cement (ordinary, early strength, very early strength, moderate heat, sulfate resistance and low alkali type of each); various mixed cements (blast furnace cement, silica cement, fly ash cement) White portland cement; alumina cement; super fast cement (1 clinker fast cement, 2 clinker fast cement, magnesium phosphate cement); grout cement; oil well cement; low heat cement (low heat blast furnace cement, fly ash mixed) Others such as low exothermic type blast furnace cement, cement with high content of belite); ultra-high strength cement; cement-based solidified material; eco-cement (cement manufactured from one or more of municipal waste incineration ash and sewage sludge incineration ash) Blast furnace slag, fly ash, cinder Ash, clinker ash, husk ash, silica fume, silica powder, and a film obtained by adding a fine powder and gypsum limestone powder.
As the above aggregate, in addition to gravel, crushed stone, granulated slag, recycled aggregate, etc., siliceous, clay, zircon, high alumina, silicon carbide, graphite, chrome, chromic, magnesia, etc. Refractory aggregate and the like.

In the cement composition, the unit water amount per 1 m ³ , the cement use amount, and the water / cement ratio are not particularly limited. For example, the unit water amount is 100 to 185 kg / m ³ , the cement amount used is 250 to 800 kg / m ³ , The water / cement ratio (weight ratio) is preferably 0.1 to 0.7. More preferably, the unit water amount is 120 to 175 kg / m ³ , the amount of cement used is 270 to 800 kg / m ³ , and the water / cement ratio (weight ratio) = 0.15 to 0.65. As described above, the cement composition of the present invention can be used widely from poor blending to rich blending, and is effective for both high-strength concrete having a large unit cement amount and poor blending concrete having a unit cement amount of 300 kg / m ³ or less. It is. In addition, the cement composition of the present invention has a relatively high water reduction rate, that is, water / cement ratio (weight ratio) = 0.15 to 0.5 (preferably 0.15 to 0.4). Even in a low cement ratio region, it can be used satisfactorily.

In addition, since the cement admixture of the present invention can exhibit excellent performances even in a high water reduction rate region with high performance and has excellent workability, it is used for ready mixed concrete and concrete secondary products (precast concrete). It can also be effectively applied to concrete, concrete for centrifugal molding, concrete for vibration compaction, steam-cured concrete, shotcrete, and the like. Also, medium-fluidity concrete (concrete with a slump value of 22-25 cm), high-fluidity concrete (concrete with a slump value of 25 cm or more and a slump flow value of 50-70 cm), self-filling concrete, self-leveling material It is also effective for mortar and concrete that require high fluidity.

In the cement composition, the blending ratio of the cement admixture of the present invention is, for example, that the polycarboxylic acid-based copolymer that is an essential component of the present invention is based on 100% by mass of the total cement mass in terms of solid content. Therefore, it is preferable to set it to be 0.01 to 10% by mass. If it is less than 0.01% by mass, the performance may not be sufficient. On the other hand, if it exceeds 10% by mass, the effect will substantially reach its peak, which may be disadvantageous in terms of economy. More preferably, it is 0.02-5 mass%, More preferably, it is 0.05-3 mass%. In the present specification, the solid content can be measured as follows.
(Solid content measurement method)
1. Weigh the aluminum dish.
The solid content to be measured is precisely weighed on the aluminum dish precisely weighed in 2.1.
3. A solid content measurement product precisely weighed in 2 is placed in a dryer adjusted to 130 ° C. in a nitrogen atmosphere for 1 hour.
4. After 1 hour, remove from the dryer and allow to cool in a desiccator at room temperature for 15 minutes.
5. After 15 minutes, remove from the desiccator and precisely weigh the aluminum dish and the measurement object.
The mass of the aluminum dish obtained in 1 is subtracted from the mass obtained in 6.5, and the solid content is measured by dividing the mass of the fixed part obtained in 2.

Since the cement admixture of the present invention is configured as described above, in addition to the dispersion performance (water reduction performance), a cement composition that is remarkably excellent in early strength development can be provided, and productivity and workability are remarkably improved. It can be improved. Therefore, a cement composition containing such a cement admixture is suitably used in the civil engineering / architectural field.

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%”.
In the following examples and the like, the measurement conditions of the weight average molecular weight (GPC measurement method) and the concrete test conditions were as follows.

<GPC measurement conditions>
The GPC measurement conditions are as follows.
Column used: TSK guard column SWXL manufactured by Tosohichi Corporation
TSKgel G4000SWXL
TSKgel G3000SWXL
TSKgel G2000SWXL connected in this order.
Eluent: A solution prepared by dissolving 115.6 g of sodium acetate trihydrate in a solution of 6001 g of acetonitrile and 10999 g of water and further adjusting the pH to 6.0 with acetic acid was used.
Sample: A polymer aqueous solution dissolved in the eluent so that the polymer concentration is 0.5% by mass.
Sample injection amount: 100 μL
Flow rate: 1.0 mL / min Column temperature: 40 ° C
Detector: Empower Software manufactured by Japan Waters
Standard material for preparing a calibration curve: polyethylene glycol [peak top molecular weight (Mp) 272500, 219300, 107000, 50000, 24000, 11840, 6450, 4250, 1470]
Calibration curve: Prepared by a cubic equation based on the Mp value and elution time of the above polyethylene glycol.

<Concrete test condition A>
(Concrete test mix)
Unit cement amount: 399.0 Kg / m ³
Unit fly ash amount: 100.0 kg / m ³
Unit water content: 164.0 Kg / m ³ (including admixtures such as copolymer, curing accelerator, antifoaming agent, etc.)
Unit fine aggregate amount: 751 Kg / m ³
Unit coarse aggregate amount: 1038 Kg / m ³
Water / Binder (*) Ratio (W / B): 32.9%
Aggregate amount ratio (s / a): 42.0%
Cement: Promotion Ordinary Portland cement fly ash: Minfeng fine aggregate: Anhui river sand coarse aggregate: Anhui crushed stone * "Binder" generally reacts with water and contributes to strength development of concrete Is a general term for materials that produce slag, including cement, fine powder of blast furnace slag, fly ash and the like. Here, it means a combination of cement and fly ash.

(Preparation of concrete composition)
The respective materials were weighed so that the mixing amount was 30 L depending on the concrete raw material and blending, and the materials were kneaded by the method described below using a forced kneading uniaxial mixer.
First, fine aggregate, coarse aggregate, cement and fly ash were kneaded for 10 seconds, and then a predetermined amount of tap water containing a cement admixture was added and kneaded for 180 seconds to obtain a concrete composition.
(Preparation of cement admixture)
A predetermined amount of the copolymer aqueous solution and the curing accelerator were weighed, and a commercially available oxyalkylene-based antifoaming agent (manufactured by BASF Pozzolith Co., Ltd., Micro Air 404) was used as the antifoaming agent, and the air amount was 1.0 ± 0.00. It adjusted so that it might become 5 vol% (volume%).

(Evaluation test items and measurement methods)
The slump flow value, air volume, and compressive strength were measured by the following methods. In addition, the material used in the test, the forced kneading mixer, and the measuring instruments are conditioned under the test temperature atmosphere so that the temperature of the concrete composition is 20 ° C. The kneading and each measurement are performed at the test temperature. Performed under atmosphere.
Slump flow value: JIS-A-1101 (revised in 2005)
Compressive strength: GB8076-1997
Air volume: JIS-A-1128 (revised in 2005)

<Concrete test condition B>
(Concrete test mix)
Unit cement amount: 573.0 Kg / m ³
Unit water amount: 172.0 Kg / m ³ (including admixtures such as copolymer, antifoaming agent, curing accelerator)
Unit fine aggregate amount: 736.0 Kg / m ³
Unit coarse aggregate amount: 866.0 Kg / m ³
Water / cement ratio (W / C): 30.0%
Aggregate amount ratio (s / a): 47.0%
Cement: Taiheiyo Cement Co., Ltd. Ordinary Portland cement fine aggregate: A mixture of mountain sand from Kimitsu and land sand from Kakegawa water system Coarse aggregate: Ome crushed stone

(Preparation of concrete composition)
Each material was weighed so that the amount of kneading became 30 L depending on the above concrete raw materials and blending, and the materials were kneaded by the method described below using a bread mixer.
First, fine aggregate and cement were kneaded for 10 seconds, and then a predetermined amount of tap water containing a cement admixture was added and kneaded for 60 seconds. Coarse aggregate was added thereto and kneaded for 90 seconds to obtain a concrete composition.
(Preparation of cement admixture)
A predetermined amount of the copolymer aqueous solution and the curing accelerator were weighed, and a commercially available oxyalkylene-based antifoaming agent (manufactured by BASF Pozzolith Co., Ltd., Micro Air 404) was used as the antifoaming agent, and the air amount was 1.0 ± 0.00. It adjusted so that it might become 5 vol% (volume%).

(Evaluation test items and measurement methods)
The slump flow value, air volume, and compressive strength were measured by the following methods. In addition, the material used for the test, the bread mixer, and the measuring instruments are conditioned under the test temperature atmosphere so that the temperature of the concrete composition becomes 20 ° C. The kneading and each measurement are performed at the test temperature. Performed under atmosphere.
Slump flow value: JIS-A-1101 (revised in 2005)
Compressive strength: JIS-A-1108 (2006 revision) (Sample preparation: JIS-A-1132 (2006 revision))
Air volume: JIS-A-1128 (revised in 2005)

Production Example 1 (Copolymer 1)
In a glass reactor equipped with a thermometer, a stirrer, a dropping device, a nitrogen introduction tube and a reflux cooling device, 144.3 g of ion-exchanged water, unsaturated polyalkylene glycol having an average of 150 moles of ethylene oxide added to methallyl alcohol 152 g of ether (addition product of methallyl alcohol 150EO), 1.37 g of acrylic acid and 5.32 g of paratoluenesulfonic acid were charged, and the inside of the reaction apparatus was purged with nitrogen under stirring, and heated to 58 ° C. in a nitrogen atmosphere. While maintaining the inside of the reaction vessel at 58 ° C., 25.0 g of a 5% hydrogen peroxide aqueous solution was added. While maintaining the inside of the reaction vessel at 58 ° C., 1351 g of 45% aqueous solution of methallyl alcohol 150EO adduct was dropped over 1 hour, and at the same time, 43.5 g of acrylic acid was dissolved in 10.9 g of ion-exchanged water. The aqueous solution was added dropwise over a period of two-thirds over the course of one-third over a period of two-thirds, and at the same time, 3.36 g of L-ascorbic acid and 3-mercaptopropion were added to 60.3 g of ion-exchanged water. An aqueous solution in which 3.08 g of acid was dissolved was dropped over 3.5 hours. Then, after maintaining the temperature at 58 ° C. for 1 hour, the polymerization reaction was terminated. Thereafter, the acidic reaction solution was neutralized to pH 6.5 with an aqueous sodium hydroxide solution at a temperature not higher than the polymerization reaction temperature to obtain an aqueous solution of copolymer 1 having a weight average molecular weight of 48,000. The aqueous solution of copolymer 1 obtained contained paratoluenesulfonic acid (salt).

Production Example 2 (Copolymer 2)
In a glass reactor equipped with a thermometer, a stirrer, a dripping device, a nitrogen introduction tube and a reflux cooling device, 225 g of unsaturated polyalkylene glycol ether obtained by adding 116 g of ion-exchanged water and 120 mol of ethylene oxide on average to methallyl alcohol. Then, 0.163 g of acrylic acid was charged, the inside of the reaction apparatus was purged with nitrogen under stirring, and heated to 58 ° C. in a nitrogen atmosphere. While maintaining the inside of the reaction vessel at 58 ° C., 17.1 g of a 2% aqueous hydrogen peroxide solution was added. An aqueous solution in which 11.3 g of acrylic acid was dissolved in 17.4 g of ion-exchanged water was dropped over 3 hours while maintaining the inside of the reaction vessel at 58 ° C., and at the same time, L-ascorbine was added to 41.3 g of ion-exchanged water. An aqueous solution in which 0.887 g of acid and 0.770 g of 3-mercaptopropionic acid were dissolved was dropped over 3.5 hours. Then, after maintaining the temperature at 58 ° C. for 1 hour, the polymerization reaction was terminated. Thereafter, the acidic reaction solution is adjusted to a temperature of not higher than the polymerization reaction temperature using an aqueous sodium hydroxide solution and ion-exchanged water so as to have a pH of 6.5 and a solid content of 45%, and a copolymer having a weight average molecular weight of 50,000. An aqueous solution of 2 was obtained.

Comparative Production Example 1 (Comparative Copolymer 1)
Add an average of 50 moles of ethylene oxide to 440 g of ion-exchanged water and 3-methyl-3-buten-1-ol in a glass reactor equipped with a thermometer, stirrer, dropping device, nitrogen inlet tube and reflux cooling device. 1025 g of the unsaturated polyalkylene glycol ether and 1.85 g of acrylic acid were charged, the inside of the reaction apparatus was purged with nitrogen under stirring, and heated to 58 ° C. in a nitrogen atmosphere. While maintaining the inside of the reaction vessel at 58 ° C., 49.7 g of a 2% hydrogen peroxide aqueous solution was added. While maintaining the inside of the reaction vessel at 58 ° C., an aqueous solution in which 71.1 g of acrylic acid was dissolved in 17.8 g of ion-exchanged water was dropped over 3 hours, and at the same time, L-ascorbine was added to 191.2 g of ion-exchanged water. An aqueous solution in which 1.29 g of acid and 2.02 g of 3-mercaptopropionic acid were dissolved was added dropwise over 3.5 hours. Then, after maintaining the temperature at 58 ° C. for 1 hour, the polymerization reaction was terminated. Thereafter, the acidic reaction solution was adjusted to a pH of 7.0 or lower with a sodium hydroxide aqueous solution and ion-exchanged water at a temperature lower than the polymerization reaction temperature, and the solid content was 40%. An aqueous solution of coalescence 1 was obtained.

<Concrete test>
In Examples 1 to 4 and Comparative Examples 1 to 6, the concrete test was performed under the concrete test condition A, and in Example 5 and Comparative Examples 7 to 9, the concrete test was performed under the concrete test condition B.

Examples 1-4
A concrete test was carried out using a cement admixture composed of the aqueous solution of copolymer 1 obtained in Production Example 1 and an organic curing accelerator (triethanolamine or triisopropanolamine) shown in Table 1. Table 1 shows the types of curing accelerators, mixing ratios of admixtures, and test results.

Comparative Examples 1-2
A concrete test was carried out using the copolymer shown in Table 1 (an aqueous solution of copolymer 1 or an aqueous solution of comparative copolymer 1) as a cement admixture and no curing accelerator. Table 1 shows the copolymer type, the blending ratio of the admixture, and the test results.

Comparative Examples 3-6
A concrete test was carried out using a cement admixture consisting of the aqueous solution of comparative copolymer 1 obtained in Comparative Production Example 1 and an organic curing accelerator (triethanolamine or triisopropanolamine) shown in Table 1. Table 1 shows the types of curing accelerators, mixing ratios of admixtures, and test results.

Example 5
A concrete test was conducted using an aqueous solution of the copolymer 2 obtained in Production Example 2 and a cement admixture composed of triisopropanolamine. Table 2 shows the mixing ratio of the admixture and the test results.

Comparative Examples 7-8
A concrete test was carried out using the copolymer shown in Table 2 (an aqueous solution of copolymer 2 or an aqueous solution of comparative copolymer 1) as a cement admixture and no curing accelerator. Table 2 shows the copolymer type, the blending ratio of the admixture, and the test results.

Comparative Example 9
A concrete test was conducted using an aqueous solution of the comparative copolymer 1 obtained in Comparative Production Example 1 and a cement admixture composed of triisopropanolamine. Table 2 shows the mixing ratio of the admixture and the test results.

In Tables 1 and 2, “addition amount (%) / cement” means the addition amount of each of the copolymer (solid content and non-volatile content of the aqueous copolymer solution) or the organic curing accelerator with respect to 100 mass% of the cement mass. (Mass%) is meant. Further, “(I) / {(A) + (I)} (%)” means organic curing with respect to 100% by mass of the total amount of the copolymer (A) and the organic curing accelerator (I). It means the amount (% by mass) of the accelerator (I).
In Table 1, “PTS content (% vs. copolymer)” means the content (% by mass) of paratoluenesulfonic acid (salt) (PTS) with respect to 100% by mass of the copolymer solid content in the cement admixture. ).

From Tables 1 and 2, Examples 1 to 4 and 5 using a specific polycarboxylic acid copolymer and an organic curing accelerator (preferably an alkanolamine compound) are compared without using an organic curing accelerator. Compared with Examples 1 and 7 respectively, the compressive strength after 1 day is increased by about 3 to 20%, and in particular, an appropriate amount (preferably the content of the organic curing accelerator is preferably a polycarboxylic acid copolymer and an organic In Examples 2, 4 and 5 in which the alkanolamine-based compound is used in an amount of 10 to 50% by mass with respect to 100% by mass of the total amount with the system curing accelerator, it may be about 15 to 20% larger. I understand. In addition, it can be seen that Examples 1 to 4 and 5 have a compressive strength of about 10 to 45% greater than Comparative Examples 2 to 6 and 8 and 9 using Comparative Copolymer 1, respectively. Therefore, it can be said that by using a cement admixture in which a specific polycarboxylic acid copolymer and an organic curing accelerator are essential, a cement cured product having remarkably excellent early strength can be obtained.

Claims (7)

A cement admixture comprising a polycarboxylic acid copolymer and an organic curing accelerator as essential components,
The polycarboxylic acid copolymer has the following general formula (1):
YO (R ¹ O) _n R ² (1)
(In the formula, Y represents an alkenyl group having 2 to 5 carbon atoms. R ¹ O is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. N represents R ¹ O. Represents an average number of added moles of the oxyalkylene group, and is a number exceeding 50 and not more than 300. R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. A cement admixture comprising a structural unit (A) derived from a saturated polyalkylene glycol ether monomer (a) and a structural unit (B) derived from an unsaturated carboxylic acid monomer (b) . The cement admixture according to claim 1, wherein the organic curing accelerator is an amine compound. The cement admixture according to claim 2, wherein the amine compound is an alkanolamine compound. The cement admixture according to claim 3, wherein the alkanolamine compound is at least one selected from the group consisting of a trialkanolamine compound and a tetraalkanolamine compound. The organic curing accelerator is 1% by mass or more and 50% by mass or less based on 100% by mass of the total amount of the polycarboxylic acid copolymer and the organic curing accelerator. cement admixture according to any one of 1 to 4. The cement admixture according to any one of claims 1 to 5, further comprising a non-polymerizable organic sulfonic acid having a molecular weight of 300 or less and / or a salt thereof. A cement composition comprising the cement admixture according to any one of claims 1 to 6, cement and water.