JPH11209155A - Cement admixture, cement composition using the same and its preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new cement admixture having activcity basically as a thickener, further having ability to suppress the separation of materials and excellent in applicability. SOLUTION: This cement admixture contains a cement additive and may further contain a cement water-reducing agent. The cement additive comprises a copolymer obtd. by polymerizing monomer components essentially including two or more alkyl (meth)acrylate monomers which are methyl acrylate and other alkyl (meth)acrylates and preferably including (meth)acrylic acid. The amt. of the methyl acrylate is equal to or larger than the amt. of the other alkyl (meth)acrylates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a cement admixture, a cement composition using the same, and a method for preparing the cement composition.

[0002]

2. Description of the Related Art At present, in cement admixtures which are materials other than cement, aggregate and water, a new cement water reducing agent and a high-performance cement admixture have been developed in order to control the hydration hardening of the cement and to improve the properties of the hardened product. Performance water reducing agent, superplasticizer, thickener, AE agent,
A great deal of research and development has been conducted on the composition of various types of admixtures such as a solidification retarder, a curing accelerator, a hydration heat inhibitor, and a drying shrinkage reducing agent, and their effects.

Under these circumstances, admixtures having various complex functions and performances have been proposed.

Specifically, in a cement composition comprising cement, water and a polymer compound, or a cement composition comprising cement, water, aggregate and a polymer compound,
Japanese Patent Laid-Open No. 3-131553 discloses a cement composition characterized by using an emulsion copolymer containing an α, β-monoethylenically unsaturated carboxylic acid as an essential monomer. In the cement composition described in the above-mentioned publication, by gelling under an alkaline atmosphere, extremely high water retention is exhibited, and in addition, troubles such as mold collapse and dryout at the time of demolding due to the action of the high water retention. It can be eliminated.

A high-performance water reducing agent comprising an aqueous mixture of a vinyl polymer emulsion and a water-soluble vinyl copolymer, wherein the aqueous mixture is twice or more in a pH range of 9 or more. The composition is disclosed in JP-A-9-71.
No. 447. In the high-performance water reducing agent composition described in the above publication, the cement composition prepared using the high-performance water reducing agent composition can simultaneously impart the desired high fluidity and material separability. is there.

[0006] Further, Japanese Patent Laid-Open Publication No. Hei 8 (1996) -1984 discloses an admixture for high-fluidity concrete containing a copolymer emulsion having a free carboxylic acid group obtained from a monomer component in a polymer chain.
No. 225353. The invention of the admixture for high-fluidity concrete described in the above-mentioned publication describes that high-fluidity concrete excellent in fluidity and filling property and excellent in separation resistance can be prepared.

Also, an emulsion of an acrylic polymer having a carboxyl group in the molecule and having an alkali-thickening property, or an admixture for ground injection containing an organic admixture thereof such as a polycarboxylic acid polymer and the like. Is disclosed in JP-A-8-1
No. 57820, and in such a synthesis example, as the emulsion of the acrylic polymer, methyl acrylate / ethyl acrylate / methacrylic acid = 24
It is exemplified that a copolymer obtained by polymerizing each monomer component of / 36/40 (% by weight) can be used.

[0008]

In such conventional cement admixtures, the cement composition is not a main component which directly and importantly plays a role in imparting various complex functions and performances to the cement composition. As an optional or incidental use, alkyl acrylate is described as one of the other monomers copolymerizable with these main components. However, with regard to the alkyl acrylate, which is only one of these other monomer components, unlike the main constituent component, what kind of effects and effects can be brought on the cement composition is not so important. But slightly as described in JP-A-3-131553.
In the specification of Japanese Patent Application Laid-Open Publication No. H10-146, there was some description that a compound having low solubility in water, such as an alkyl acrylate, was better. Accordingly, there is no report on the specific action and effect that methyl acrylate, which is one specific example of the alkyl acrylate, can have on the cement composition.

On the other hand, in such conventional cement admixtures, efforts have been made to develop new admixtures having newly added various complex functions and performances. In terms of workability, which is a technical problem to be solved when preparing a product, particularly in terms of significantly shortening the kneading time of the cement composition, etc., what components effectively contribute has not been found at all. It is the current situation.

Accordingly, an object of the present invention is to provide a cement admixture which basically has a function as a thickener, further has a property of reducing the separation of materials, and has a workability, especially a kneading time of the cement composition. To provide a novel cement admixture which can significantly reduce the viscosity of the cement and a cement composition using the same.

[0011] Another object of the present invention is to provide a cement composition using a novel cement admixture.
In particular, the present invention provides a method for preparing a cement composition that can significantly shorten the kneading time of the cement composition.

[0012]

In order to achieve the above objects, the present inventors have conducted intensive studies on a cement admixture, a cement composition using the same, and a method for preparing the same. The main component is at least two or more alkyl (meth) acrylate-based monomers composed of other alkyl (meth) acrylates, and the amount of the methyl acrylate is other alkyl (meth) acrylate; A copolymer obtained by polymerizing a monomer component that is equal to or more than the amount of the ester has a function and effect unique to the present invention, which has both functions of a thickener and a material separation reducing agent. In addition, a cement water reducing agent is used in combination with a cement additive made of the copolymer, and at least the cement water reducing agent is dissolved or dispersed in kneading water in advance, and this is mixed. By introducing kneaded into the system,
Furthermore, they have found that a further unique function and effect of promoting the improvement of workability can be exhibited, and based on this finding, the present invention has been completed.

That is, a first object of the present invention is to provide (1)
As a main component, at least two or more (meth) acrylic acid alkyl ester-based monomers composed of methyl acrylate and other (meth) acrylic acid alkyl esters, and the amount of the methyl acrylate is other (meth) )
This is achieved by a cement admixture characterized by containing a cement additive consisting of a copolymer obtained by polymerizing a monomer component having an amount equal to or more than the amount of the alkyl acrylate.

Further, a first object of the present invention is to provide (2) the cement additive, wherein the cement additive is at least two or more alkyl (meth) acrylates comprising methyl acrylate and another alkyl (meth) acrylate; It is also achieved by the cement admixture according to the above (1), which comprises a copolymer obtained by polymerizing a monomer component containing an ester monomer and (meth) acrylic acid. .

Further, a first object of the present invention is to provide (3)
This is achieved by a cement admixture comprising the cement additive described in (1) or (2) and a cement water reducing agent.

The second object of the present invention is achieved by (4) a cement composition comprising at least a cement admixture, cement and kneading water according to any one of the above (1) to (3). Is done.

A third object of the present invention is to provide (5) a method of dispersing or dissolving a cement water reducing agent and the cement additive as described in (1) or (2) above in a part or all of the kneading water to form a mixture in a mixed system. And kneading by kneading.

[0018] A third object of the present invention is to provide (6) the cement additive and the cement water reducing agent as described in (1) or (2) above, each of which is dispersed or dissolved in a part of kneading water. This is achieved by a method for preparing a cement composition, which comprises simultaneously introducing and kneading a liquid containing a cement additive and a liquid containing a cement water reducing agent according to (1) or (2).

A third object of the present invention is to provide (7) the above (1) or (2) wherein the cement additive described in (1) or (2) is dispersed or dissolved in a part of the kneading water. The cement additive-containing liquid described in 2) is charged into the mixing system and kneaded, and then the cement water-reducing agent-containing liquid obtained by dispersing or dissolving the cement water-reducing agent in a part of the kneading water is charged and further kneaded. This is achieved by a method for preparing a cement composition, which comprises:

A third object of the present invention is to provide (8) a state in which the mixed system contains cement, cement and fine aggregate, and cement, fine aggregate and coarse aggregate. The cement composition according to any one of the above (5) to (7), wherein the cement composition is in a state in which the cement composition does not contain any of cement, fine aggregate and coarse aggregate. Achieved by the preparation method.

A third object of the present invention is that (9) the mixed system contains cement, cement and fine aggregate, or cement, fine aggregate and coarse aggregate. This is achieved by the method for preparing a cement composition as described in (8) above, wherein the composition components in the mixed system are kneaded in the mixed state.

A third object of the present invention is to provide (10)
When the mixed system does not contain any of cement, fine aggregate and coarse aggregate, the cement water reducing agent according to any one of the above (5) to (7) and the above (1)
Or kneading water in which the cement additive according to (2) is dispersed or dissolved, the cement additive-containing liquid and the cement water-reducing agent-containing liquid according to (1) or (2), or the above (1) or (2) The above-mentioned (5) to (5) to (5) to (5), wherein the cement additive-containing liquid described in (1) and at least cement among cement, fine aggregate and coarse aggregate are put into the mixing system at a time and kneaded. This is achieved by the method for preparing a cement composition according to any one of (7).

A third object of the present invention is to provide (11)
The method for preparing a cement composition according to any one of the above (5) to (7), wherein at least one of a cement admixture excluding a cement water reducing agent is contained in the mixed system. Is achieved by

A third object of the present invention is to provide (12)
Achieved by the method for preparing a cement composition according to the above (11), wherein the cement admixture other than the cement water reducing agent contains a solid cement additive according to the above (1) or (2). Is done.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The cement admixture of the present invention comprises at least two or more alkyl (meth) acrylate-based monomers composed of methyl acrylate and other alkyl (meth) acrylates as main components. And a copolymer (hereinafter simply referred to as (meth) acrylic acid) obtained by polymerizing a monomer component in which the amount of the methyl acrylate is equal to or more than the amount of the other alkyl (meth) acrylate. Characterized by containing a cement additive consisting of an alkyl ester monomer as a main component). Preferably, the cement additive comprises methyl acrylate and other (Meth) acrylic acid alkyl ester and at least two kinds of (meth) acrylic acid alkyl ester-based monomers and (meth) acrylic acid (Hereinafter referred to simply as a copolymer obtained by polymerizing a monomer component containing (meth) acrylic acid alkyl ester-based monomer and (meth) acrylic acid). (Also abbreviated as a polymer).

The above methyl acrylate and other (meth)
The amount of the methyl acrylate is at least two or more kinds of (meth) acrylic acid alkyl ester-based monomers, and the amount of the methyl acrylate is the same as the amount of other (meth) acrylic acid alkyl esters. At least one of alkyl (meth) acrylates other than methyl acrylate, which is an essential monomer component for polymerizing a copolymer obtained by polymerizing a monomer component having an amount of at least one. The above (meth) acrylic acid alkyl ester-based monomer is not particularly limited, but preferably, the alkyl group of the acrylic acid alkyl ester has 2 to 12 carbon atoms or the alkyl methacrylate ester Is an alkyl group having 1 to 1 carbon atoms
Two. Examples of the alkyl (meth) acrylate include methyl methacrylate, ethyl (meth) acrylate, propyl (meth) acrylate,
Examples include butyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, and the like.

The above-mentioned methyl acrylate and other (meth)
In a copolymer containing alkyl acrylate and at least two kinds of alkyl (meth) acrylate monomers as main components, the amount of methyl acrylate is other than (methyl) acrylate other than methyl acrylate. It must be equal to or greater than the total amount of the alkyl acrylate. Main ingredient methyl acrylate and other (meth)
Preferably 50% or more alkyl acrylate,
More preferably, those containing 60% or more are desirable.
Among them, a main component composition containing 30% or more of methyl acrylate is particularly desirable. When the content of methyl acrylate and other alkyl (meth) acrylates is less than 50% as monomer components, it has both functions as a thickener and a material separation / reduction agent. Excellent in nature,
In addition, while maintaining these functions, the required amount for achieving the same function and effect can be reduced, which is not preferable because the function and effect unique to the present invention cannot be obtained. Further, in order to provide different functions depending on the other polymerizable monomer components, from the viewpoint that the function cannot be effectively exhibited unless it contains a certain amount or more, as a preferred range, methyl acrylate and The amount of other alkyl (meth) acrylates is specified. This is because methyl acrylate is important in order to show the flowability and separation resistance of the preferred cement composition, and their performance decreases as other (meth) acrylic acid alkyl esters become higher than methyl acrylate It is to let.

The reason why a polymer containing methyl acrylate as a main component can exhibit these properties has not yet been elucidated. However, the methyl acrylate portion in the polymer is used in an alkaline atmosphere such as in a cement composition. It has been found below that rapid hydrolysis and generation of carboxyl groups are related to the fluidity and separation resistance of the cement composition.

However, (meth) other than methyl acrylate
When the acrylic acid alkyl ester is not contained at all, the hydrolysis of methyl acrylate cannot be controlled, and the fluidity of the cement composition changes with time, or the fluidity extremely decreases, which is not preferable.

In addition, at least two types of copolymers comprising methyl acrylate and other alkyl (meth) acrylates, which are preferable as a copolymer containing the above-mentioned alkyl (meth) acrylate-based monomer as a main component, In the copolymer obtained by polymerizing the above-mentioned (meth) acrylic acid alkyl ester-based monomer and the monomer component containing (meth) acrylic acid, the (meth) acrylic acid alkyl ester should be the main component. Although there is no change, the remaining (meth) acrylic acid monomer component is preferably contained in an amount of 0 to 50% by weight, preferably 5 to 40% by weight, based on all the monomer components. If the amount of (meth) acrylic acid exceeds 50% by weight, the amount of the alkyl (meth) acrylate, which is the main component, is reduced, so that sufficient separation resistance cannot be obtained or the kneading of the cement composition. This is not preferable because the time becomes extremely long.

At least two kinds of (meth) acrylic acid alkyl ester monomers composed of the above-mentioned methyl acrylate and other (meth) acrylic acid alkyl esters and polymerizable monomers other than (meth) acrylic acid. As the body component, as one of the components of various admixtures capable of expressing various functions and performances conventionally known, those capable of exhibiting the effect can be particularly preferably used, The present invention is not limited to these, and it is possible to widely use monomers copolymerizable with the above-mentioned monomer components. Examples thereof include itaconic acid, crotonic acid, maleic acid, and maleic anhydride ( Carboxyl group-containing polymerizable monomers excluding (meth) acrylic acid; sulfonic acids such as vinylsulfonic acid, styrenesulfonic acid, and sulfoethyl (meth) acrylate Containing polymerizable monomer; 2- (meth) acryloyloxyethyl acid phosphate,
Acidic phosphate-based polymerizable monomers such as 2- (meth) acryloyloxypropyl acid phosphate, 2- (meth) acryloyloxy-3-chloropropyl acid phosphate, 2- (meth) acryloyloxyethyl phenyl phosphate; styrene , Styrene derivatives such as vinyltoluene, α-methylstyrene, chloromethylstyrene; (meth) acrylamide, N-monomethyl (meth) acrylamide, N-monoethyl (meth)
(Meth) acrylamide derivatives such as acrylamide and N, N-dimethyl (meth) acrylamide; polymerizable monomers having a cycloalkyl group such as cyclohexyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, (meth) acrylate 2-hydroxypropyl acrylate, hydroxyl group-containing (meth) acrylates such as monoester of (meth) acrylic acid and polypropylene glycol; polyethylene glycol chain-containing polymerizable monomers such as polyethylene glycol (meth) acrylic ester ;
Vinyl acetate; (meth) acrylonitrile; N-vinylpyrrolidone; dimethylaminoethyl (meth) acrylate;
Basic polymerizable monomers such as dimethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, vinylpyridine, and vinylimidazole;
Crosslinkable (meth) acrylamides such as N-methylol (meth) acrylamide and N-butoxymethyl (meth) acrylamide; vinyltrimethoxysilane, vinyltriethoxysilane, γ- (meth) acryloylpropyltrimethoxysilane, vinyltris (2 A polymerizable monomer having a hydrolyzable silicon group directly bonded to a silicon atom such as -methoxyethoxy) silane or allyltriethoxysilane; a polymerizable monomer having an epoxy group such as glycidyl (meth) acrylate or acrylic glycidyl ether Oxazoline group-containing polymerizable monomers such as 2-isopropenyl-2-oxazoline and 2-vinyloxazoline; and aziridinyl groups such as (meth) acrylic acid-2-aziridinylethyl and (meth) acryloylaziridine Polymerizable monomer: vinyl fluoride, vinyl fluoride Halogen-containing polymerizable monomers such as den, vinyl chloride and vinylidene chloride; (meth) acrylic acid and ethylene glycol, 1,3-butylene glycol, diethylene glycol, 1,6-hexanediol, neopentyl glycol, polyethylene glycol, propylene Polyfunctional (meth) having two or more polymerizable unsaturated groups in the molecule, such as esterified products with polyhydric alcohols such as glycol, polypropylene glycol, trimethylolpropane, pentaerythritol and dipentaerythritol
Acrylic acid esters; polyfunctional (meth) acrylamides having two or more polymerizable unsaturated groups in a molecule such as methylenebis (meth) acrylamide; diallyl phthalate;
Polyfunctional allyl compounds having two or more polymerizable unsaturated groups in the molecule, such as diallyl maleate and diallyl fumarate;
(Meth) acryl allyl, divinylbenzene, and the like. At least two or more types of alkyl (meth) acrylate-based monomers composed of methyl acrylate and other alkyl (meth) acrylates and polymerizable monomer components other than the (meth) acrylic acid monomer component As these, one or more of these polymerizable monomers and polymerizable polyfunctional monomers can be used as a mixture.

Further, a copolymer containing the above-mentioned (meth) acrylic acid alkyl ester-based monomer as a main component, more preferably, a (meth) acrylic acid alkyl ester-based monomer and (meth) acrylic acid The method for producing the copolymer obtained by polymerizing the monomer components is not particularly limited, and known methods such as bulk, solution, dispersion, and suspension are applied to the production method. Among them, methyl acrylate, other (meth) acrylic acid alkyl esters, furthermore, (meth) acrylic acid and other monomer components in the above-mentioned ratios can be prepared by using known emulsifiers, polymerization initiators, and chain transfer. It can be easily obtained by copolymerization using an agent or the like by a conventionally known emulsion polymerization method.

Here, as the emulsifier, any surfactant such as an anionic surfactant, a nonionic surfactant, a cationic surfactant, an amphoteric surfactant or a polymer surfactant can be used. Depending on the case, the polymerization may be performed without using any emulsifier.

Examples of the anionic surfactant include alkyl sulfate salts such as sodium dodecyl sulfate, potassium dodecyl sulfate and ammonium alkyl sulfate; sodium dodecyl polyglycol ether sulfate; sodium sulfolisinoate; sulfonated paraffin salts and the like. Alkyl sulfonates such as sodium dodecylbenzene sulfonate, alkali metal sulfate of alkali phenol hydroxyethylene; high alkyl naphthalene sulfonate; naphthalene sulfonic acid formalin condensate, sodium laurate, triethanolamine oleate, triethanolamine Fatty acid salts such as ahiate; polyoxyalkyl ether sulfates; poly Reactive anionic emulsifiers having a double bond such as xylethylene carboxylate sulfate, polyoxyethylene phenyl ether sulfate; dialkyl succinate sulfonate; polyoxyethylene alkylaryl sulfate, etc. can be used. .

Examples of the nonionic surfactant include polyoxyethylene alkyl ether; polyoxyethylene alkyl aryl ether; sorbitan aliphatic ester; polyoxyethylene sorbitan aliphatic ester; and glycerol monolaurate. Aliphatic monoglyceride; polyoxyethyleneoxypropylene copolymer, ethylene oxide and aliphatic amine,
Condensation products with amides or acids can be used.

As the above-mentioned polymer surfactant, for example,
Polyvinyl alcohol and modified products thereof; (meth) acrylic acid-based water-soluble polymer; hydroxyethyl (meth) acrylic acid-based water-soluble polymer; hydroxypropyl (meth) acrylic acid-based water-soluble polymer; .

When the above-mentioned emulsifier is used, the amount of the emulsifier used may be any as long as it can exhibit the desired function of assisting the formation of the emulsion and stabilizing the formed emulsion. ) It is usually 0.1 to 10% by weight, preferably 1 to 5% by weight, based on all the monomer components of the acrylic acid alkyl ester, further (meth) acrylic acid and other monomer components. If the amount of the emulsifier is less than 0.1% by weight, the stability of the emulsion polymerization is remarkably lost, a large amount of aggregates are generated, or the whole is aggregated. On the other hand, when the use amount of the emulsifier exceeds 10% by weight, the curing of the cement composition is delayed or excessive air is entrained.

As the above-mentioned polymerization initiator, for example, persulfates such as potassium persulfate, ammonium persulfate, sodium persulfate and the like, which are substances which decompose by heat to generate molecules having radicals; 2,2'-azobis ( Water-soluble azo compounds such as 2-amidinopropane) dihydrochloride and 4,4'-azobis (4-cyanopentanoic acid); a thermal decomposition initiator such as hydrogen peroxide; and a combination of an oxidizing agent and a reducing agent. Redox polymerization initiators such as hydrogen peroxide and ascorbic acid, t-butyl hydroperoxide and Rongalit, potassium persulfate and metal salts, and ammonium persulfate and sodium bisulfite to generate molecules having radicals in the oxidation-reduction reaction. And one or more of these can be used as a mixture.

The amount of the polymerization initiator to be used is not particularly limited as long as it can easily generate free radicals or ions and exhibit the desired function of initiating polymerization by a chain reaction. (Meth) acrylic acid alkyl ester, furthermore, (meth) acrylic acid, usually 0.001 to 1% by weight, preferably 0.01% by weight, based on all monomer components of other monomer components.
~ 0.5% by weight. The amount of the polymerization initiator used is 0.00
When the amount is less than 1% by weight, the polymerization becomes extremely slow,
Polymerization does not start. On the other hand, when the use amount of the polymerization initiator exceeds 1% by weight, the polymerization becomes unstable and aggregates increase.

Further, at the time of the above-mentioned emulsion polymerization, it is possible to appropriately add various known hydrophilic solvents and additives as described below as necessary, as long as the physical properties are not adversely affected. . In preparing the emulsion polymer, a chain transfer agent may be used for controlling the molecular weight. Examples of the chain transfer agent include t-dodecyl mercaptan (1,1-dimethyldecane-1-thiol), 1-hexadecanethiol, 1,10-decanethiol, 1,8-dimercapto-3,6-dioxa. Octane, 1,5,10-decanetrithiol, 2-ethylhexyl mercaptopropionate, 2-mercaptoethyl octanoate, carbon tetrachloride, carbon tetrabromide, α-methylstyrene dimer, terpinolene, α
-Terpinene, β-terpinene, dipentene, allyl alcohol, 2-amino-propanol and the like.
Further, in order to promote the emulsion polymerization, for example, reducing agents such as sodium pyrobisulfite, sodium sulfite, sodium bisulfite, ferrous sulfate, formaldehyde sodium sulfoxylate, L-ascorbic acid and salts thereof, for example, , Sodium ethylenediaminetetraacetate,
A chelating agent such as glycine can be used in combination. In addition, for example, a dispersant such as sodium polyacrylate, an electrolyte such as potassium chloride, disodium phosphate, trisodium phosphate, diammonium phosphate, sodium pyrophosphate, sodium tripolyphosphate, a pH adjuster, and the like. They can be used together. The amount of these additives may be appropriately added as long as the physical properties are not adversely affected.

The method of adding the above-mentioned various monomer components to the polymerization reaction system is not particularly limited, and a batch addition method, a monomer dropping method, a pre-emulsion method, a power feed method,
Any conventionally known method such as a seed method or a multi-stage addition method can be used.

The nonvolatile content of the polymer emulsion after the above emulsion polymerization is preferably 60% or less. If the nonvolatile content is more than 60%, the viscosity is too high,
Aggregates without maintaining dispersion stability. The number average molecular weight of the polymer obtained by the emulsion polymerization method by GPC is as follows:
It is usually 100,000 to 10,000,000, preferably 500,000 to 2,000,000. When the number average molecular weight is less than 100,000, the separability of the cement composition is significantly reduced. On the other hand, when the number average molecular weight exceeds 10,000,000, the fluidity of the cement composition is impaired. When the polymer obtained by the emulsion polymerization method is held in the form of an emulsion, the pH of the polymer is usually adjusted to 1 to 7, particularly in consideration of the emulsion stability. , Should be kept.

When the particle size of the dispersion is less than 0.001 μm, the surface area of the particles is considerably increased, so that a large amount of an emulsifier is required, and the viscosity of the emulsion itself is considerably increased at a low solid content. Therefore, it is not suitable for this use. If the dispersion exceeds 1 μm, it is difficult to produce the dispersion by ordinary emulsion polymerization, and it is not suitable for this application because it cannot be stably present as an emulsion and particles settle.

On the other hand, the copolymer polymerized by these methods is dried and pulverized, salted out, coagulated sedimentation method, freeze-dried method, coagulated pulverization method, spray-dry, belt dryer, etc. It may be used in a form as a kind of cement admixture.

When used in the form of a dry powder or a slurry, it is usually 1 to 10,000 μm, preferably 10 to 10,000 μm.
It is appropriate to form a particle size of １０００1000 μm. When the particle size is less than 1 μm, the bulk of the powder becomes large and the powder easily scatters in the air, so that handling becomes difficult. In addition, even in the case of a slurry, the viscosity of the slurry itself becomes too high and becomes close to a gel, so that handling becomes difficult.

When the particle size exceeds 10,000 μm,
Since it does not dissolve quickly, it takes a long time to obtain sufficient viscosity and separation resistance. As a result, the productivity of concrete is reduced, and fine adjustment of fluidity or the like depending on the amount of addition becomes considerably difficult.

The cement additive comprising a copolymer containing the alkyl (meth) acrylate as a main component does not dissolve in acidic or neutral water, but does not dissolve in an alkali such as an aqueous alkali solution or cement paste. Methyl acrylate in the coalesce is sequentially hydrolyzed to form a carboxyl group, so that part or all of the copolymer is dissolved to have a high viscosity. A cement additive composed of a copolymer containing a (meth) acrylic acid alkyl ester-based monomer as a main component and exhibiting a suitable fluidity and separation resistance of a cement composition is copolymer 1 as the cement additive. In water containing 10% by weight, a part or the whole is dissolved when the pH is 9, and the viscosity after dissolution is 50 to 50%.
Those showing 5000 mPa · s are particularly effective.

The amount of the cement additive composed of a copolymer containing the above-mentioned alkyl (meth) acrylate monomer as a main component is uniformly defined because the appropriate amount varies depending on the intended use and the kind used. It is not possible to exert its properties, such as its thickening action and material separation reducing action, which are the purpose of its use, and in addition to this action, it has an effect on the workability when preparing cement compositions such as concrete and mortar. The amount of the more effective effect may be blended within a range in which the desired desired action and effect can be usefully exhibited. The amount of the (meth) acrylic acid alkyl ester relative to the weight of the cement used is not particularly limited. Cement additive consisting of a copolymer containing a monomer as a main component is used in an amount of from 0.001% to 5%, preferably from 0.01 to 5% in terms of dry resin or solid content.
It is desirable to contain 1%. When the content of the cement additive composed of a copolymer having a (meth) acrylic acid alkyl ester-based monomer as a main component is less than 0.001%,
Sufficient separation resistance cannot be obtained. On the other hand, when the content of the cement additive composed of a copolymer containing a (meth) acrylic acid alkyl ester-based monomer as a main component exceeds 5%, the fluidity of a cement composition such as concrete is impaired. Would.

Next, the cement admixture of the present invention includes, in addition to the above-mentioned cement additive composed of a copolymer containing a (meth) acrylic acid alkyl ester-based monomer as a main component,
An appropriate admixture can be used in combination depending on the purpose of use, use, and the like.

In particular, in the method for preparing a cement composition using the cement admixture of the present invention, in order to obtain excellent workability, the above alkyl (meth) acrylate having a function as a thickener is required. A cement additive comprising a copolymer containing a monomer as a main component and a conventionally known arbitrary cement water reducing agent are used in combination, and at least the cement water reducing agent is dispersed or dissolved in kneading water in advance as described later. It turned out that it is desirable to add and knead this.

The cement water reducing agent that can be blended as one of the cement admixtures of the present invention is not particularly limited to its name, but adsorbs on the surface of cement particles to cause repulsion between each other. The surfactant to be used is not limited as long as it can reduce the unit water amount of the cement composition such as concrete by this action and increase the strength, and further imparts another action to this, for example, an air entrainment action. AE water reducer, which has a high-performance water reducer that can significantly reduce the water-cement ratio to obtain a cement composition such as high-strength concrete, while maintaining the quality of cement composition such as kneaded concrete Fluid, a high-performance water reducing agent used in cement compositions such as concrete for fluidization, which has the effect of maintaining high workability (workability) for a certain period of time And various types of cement water reducers, AE water reducers, high performance water reducers, high performance AE water reducers, superplasticizers or cement dispersants which have been developed to date. In addition, even if it is described only as a cement or concrete admixture, judging from its components, it can be widely applied to those contained in the cement water reducing agent, for example, lignin sulfonate System, oxycarboxylic acid salt system, polyol derivative system, naphthalenesulfonic acid formalin condensate system, alkylnaphthalenesulfonic acid formalin condensate system, melaminesulfonic acid formalin condensate system, phenolsulfonic acid formalin condensate system (Patent Publication No. 1097647) ), Phenolsulfanilic acid formalin condensate (JP-A-1-11341) JP),
Phenol melamine methylolated sulfonic acid formalin condensate (Japanese Patent Application Laid-Open No. 56-13674), polycarboxylic acid type (Japanese Patent Application Laid-Open No. Hei 7-2677056, Japanese Patent No. 2508113, Japanese Patent Application Laid-Open No. 62-216950), Japanese Unexamined Patent Publication No. Hei 1-222657, Japanese Patent Publication 5-363
No. 77, Japanese Unexamined Patent Application Publication No. 4-149056, Japanese Unexamined Patent Application Publication No.
-170501, JP-A-6-191918, JP-A-5-43288, JP-B-58-383.
No. 80, Japanese Patent Publication No. Sho 59-18338,
JP-A 2-119147), polystyrene sulfonate (JP-A-51-525, JP-A-56-41)
866), and these can be used alone or in an appropriate combination of two or more.

The amount of the cement water reducing agent to be added cannot be specified uniformly because its proper amount varies depending on the kind used and the like, and the water reducing effect which is the purpose of use is usefully exhibited. What is necessary is just to mix the amount which raises the effect within the range in which the effect of increasing the strength by reducing the unit water amount of the cement composition can be usefully exhibited, and is not particularly limited. 0.01 to 3%, preferably 0.02 to 2%, more preferably 0.04 to 100% of cement weight
It is formulated to be able to contain 1%, achieving high water reduction rate, improving slump loss prevention performance, reducing unit water volume,
It is desirable because various favorable effects such as an increase in strength and an improvement in durability are brought about. When the content of the cement water reducing agent is less than 0.01% based on the weight of cement, a sufficient water reducing action cannot be exhibited effectively, and the unit water amount of a cement composition such as concrete cannot be reduced.
Further, the properties of the paste as a cement composition such as concrete that has not yet solidified are not sufficiently improved, and the fluidity cannot be improved. On the other hand, even if the content of the cement water reducing agent exceeds 3% based on the weight of cement and is used in a large amount, the effect is substantially flattened, which is disadvantageous in terms of economy.

Further, as the cement admixture, besides the cement additive and the cement water reducing agent consisting of the copolymer containing the above-mentioned alkyl (meth) acrylate monomer as a main component, if necessary, a conventional cement admixture may be used. Known admixtures may be added. Examples of such admixtures include air entrainers, cement wetting agents, swelling agents, waterproofing agents, retarders, quick-setting agents, flocculants, drying shrinkage reducing agents, and strength enhancers. Agents, curing accelerators, fillers, antifoaming agents, foaming agents, coloring agents, flame retardants, preservatives, water resistance agents, antioxidants, stabilizers, vulcanization accelerators, antistatic agents, and the like. Blast furnace slag, pozzolan, fly ash, silica fume, limestone, an expanding material mainly containing minerals such as CaO and C ₃ A ₃ CaSO ₄ may be used as the fine powder admixture. The timing of the addition of these admixtures is not particularly limited, and a cement additive and a cement water reducing agent comprising a copolymer containing the above-mentioned alkyl (meth) acrylate-based monomer as a main component are used. There is no particular need to dissolve or diffuse in the kneading water in advance, as in the prior art, and may be appropriately added in the same manner as in the past, and the addition amount is within a range where the performance of the admixture can be effectively exhibited. If there is,
It can be as usual.

The cement admixture of the present invention described above comprises:
In addition to ordinary general mortar and concrete, high-fluidity concrete, underwater inseparable concrete, sprayed concrete, back-cast concrete, ground injection (improved)
It can be used for cement, mortar, concrete, etc. such as construction methods, concrete moldings, and shield construction methods.

Next, the cement composition according to the present invention comprises a cement additive comprising a copolymer containing the above-mentioned alkyl (meth) acrylate monomer as a main component, preferably the cement admixture and the cement water reducing agent. It contains at least a cement admixture containing an agent, cement and water. The cement composition according to the present invention includes at least the cement admixture, a cement paste which is a mixture of cement and water (hereinafter, also simply referred to as a paste), and the cement admixture. Mortar, which is a mixture of cement, fine aggregate and water (hereinafter simply referred to as mortar), a mixture of the above cement admixture, cement, aggregate and water, As the aggregate, cement concrete in which at least coarse aggregate is blended (for example, a cement concrete in which coarse aggregate is blended or a mixture in which both fine aggregate and coarse aggregate are blended) is applicable. (In this specification,
(Also simply referred to as concrete), but is not limited thereto.

Here, the cement is not particularly limited as long as it can be used for a cement composition, specifically, a paste, mortar or concrete. Hydraulic materials other than cement, such as various types of Portland cement such as early strength, moderate heat, and white, belite-rich cement, alumina cement, fly ash cement, blast furnace cement, silica cement, various mixed cements, etc. And so on.

The amount of the above-mentioned cement is appropriately determined according to the purpose of use, purpose of use, etc., and usually, various properties such as fluidity and uniformity generally desired for a cement composition such as concrete are used. In order to provide the properties, the cement is used in an amount of 150 to 70 per m ^{3 of} the cement composition used.
0 kg / m ³ , preferably 200 to 650 kg / m ³ ,
More preferably, the content is 250 to 600 kg / m ³ . The content of cement is 150 kg / m ³
If it is less than 10, sufficient strength cannot be obtained due to a small amount of cement. On the other hand, the content of the cement is 700 kg / m
^When it exceeds ³ , although the strength by the cement is obtained, the strength of the whole cement composition such as concrete is not sufficient because the unit bone material is reduced.

The above-mentioned fine aggregate refers to an aggregate in which a 10 mm net sieve is used as a whole and a 5 mm net sieve accounts for 85% by weight or more. Specifically, for example, river sand, mountain sand, crushed sand,
Sea sand, fly ash, artificial lightweight aggregate and the like can be mentioned, and these can be used alone or in an appropriate combination of two or more.

The amount of the fine aggregate to be used is as follows.
Although it is appropriately determined according to the use and the like, usually, in order to have various properties such as fluidity and uniformity generally desired for a cement composition such as mortar or concrete, a cement composition to be used is used. 1m ³ per fine aggregate 500 to 1
500 kg / m ³ , preferably 550-1200 kg /
m ³ , more preferably 600 to 1000 kg / m ³ . 500kg fine aggregate content
If it is less than / m ³ , the amount of coarse bone material increases and material separation easily occurs. On the other hand, the content of the fine aggregate is 1500
If the amount exceeds kg / m ³ , the separation resistance will occur and the fluidity will be impaired, and the strength will also decrease due to the decrease in unit bone material.

The above-mentioned coarse aggregate refers to an aggregate that is contained in a 5 mm mesh sieve at 85% by weight or more. Specifically, for example, river gravel, mountain gravel, crushed stone, sea sand, chestnut stone, blast furnace slag crushed stone, Light natural gravel, artificial lightweight aggregate, and the like as natural lightweight aggregates can be mentioned, and these can be used alone or in an appropriate combination of two or more.

The amount of the coarse aggregate may be selected depending on the purpose of use,
Although it is appropriately determined according to the use and the like, usually, in order to have various properties such as fluidity and uniformity generally desired for a cement composition such as mortar or concrete, a cement composition to be used is used. 1m ³ per, the coarse aggregate 500 to 1
500 kg / m ³ , preferably 550-1200 kg /
m ³ , more preferably 600 to 1000 kg / m ³ . 500kg of coarse aggregate content
If it is less than / m ³ , the amount of unit coarse bone material is reduced, and sufficient strength is not obtained. On the other hand, when the content of the coarse aggregate is 150
If it exceeds 0 kg / m ³ , material separation is likely to occur.

Further, the use amount of the kneading water, that is, the unit water amount is not particularly limited, but a unit water amount of 120 to 200 kg / m ³ per m ^{3 of} concrete to be used is recommended. Also, the amount of cement and mixing water used is
It is desirable to adjust the water / cement ratio within a range of 20 to 70, preferably 30 to 60.

The method for preparing the cement composition of the present invention is not particularly limited, and a conventionally known preparation method can be applied. As a specific example, when preparing a mortar or concrete as a cement composition, for example, first, as shown in FIG.
(1) Fine aggregate such as cement and sand is put into a suitable mixer and kneaded. Thereby, the fine aggregate and the cement are uniformly mixed.

(2) Next, the kneading water and the above (meth)
The fine aggregate prepared by the kneading of the cement admixture of the present invention containing the cement additive comprising a copolymer mainly composed of an alkyl acrylate monomer as a main component, a cement water reducing agent, etc. Put into cement and knead. By the kneading, a uniform mortar is prepared. The above is the method of preparing the mortar.

(3) If necessary, a concrete can be prepared by adding coarse aggregate such as gravel to the mortar prepared by kneading in (2) and further kneading.

In the present invention, in addition to the method of preparing the cement composition according to the procedure shown in FIG. 1 (a), the cement after kneading the cement, the kneading water and, if necessary, the aggregate is used. A method of post-adding the cement admixture of the present invention to a mixture (here, a mixture of a cement composition other than a cement admixture), and the whole or a part of the kneading water used for kneading is added to the cement of the present invention. A method of dispersing or dissolving the admixture and then kneading the cement and the aggregate can be applied. Although such a conventionally known preparation method may be used, the present inventor has found that the preparation method shown below is excellent, from the viewpoint of workability, particularly from the viewpoint of shortening the kneading time, which will be described below. I do.

A preferred method for preparing the cement composition of the present invention comprises a cement water-reducing agent and a copolymer containing the above-mentioned alkyl (meth) acrylate-based monomer as a main component in part or all of the kneading water. It is characterized by dispersing or dissolving a cement additive (hereinafter, also simply referred to as a cement additive or a thickener), introducing the mixture into a mixing system, and kneading the mixture.

In the present invention, the preparation method can be appropriately applied or modified based on the above basic concept. That is, as another preferred embodiment of the method for preparing the cement composition of the present invention, a cement additive (a thickener) obtained by dispersing or dissolving a cement additive and a cement water reducing agent in a part of kneading water, respectively. ) A liquid containing a cement and a liquid containing a cement water reducing agent are simultaneously charged into a mixing system and kneaded. Further, as still another embodiment of the method for preparing a cement composition according to the present invention, a cement additive (thickener) obtained by dispersing or dissolving a cement additive (thickener) in a part of kneading water. It is characterized in that the liquid containing is poured into the mixing system and kneaded, and then the liquid containing the cement water reducing agent obtained by dispersing or dissolving the cement water reducing agent in a part of the kneading water is further kneaded. is there.

The mixed system may contain cement, cement and fine aggregate, cement, fine aggregate and coarse aggregate, or cement, fine aggregate and coarse aggregate. Desirably, the material does not contain any of the materials, but is not limited thereto.

When the mixed system contains cement, cement and fine aggregate, or cement, fine aggregate and coarse aggregate, the mixed system may contain These composition components in the mixed system may be kneaded before the kneading water is introduced into the mixed system. When kneading, it is only necessary to be able to uniformly mix these composition components, and the kneading time required to prepare these composition components into a uniform mixture by kneading is determined by the mixing machine used. It depends on the performance, cement, aggregate (fine aggregate, coarse aggregate) and the amount of cement mixture, etc.
Usually, about 5 to 60 seconds is sufficient.

When the mixed system contains cement, cement and fine aggregate, or cement, fine aggregate and coarse aggregate, the mixture may further include At least one of the cement admixtures excluding the cement water reducing agent may be contained in the mixed system. It is particularly preferable that the cement admixture except for the cement water reducing agent is a cement admixture containing a solid cement additive (thickener).

On the other hand, when the mixed system does not contain any of cement, fine aggregate and coarse aggregate, kneading water is added to the mixed system (more specifically, in the above-described embodiment). Water in which a cement water reducing agent and a cement additive (thickener) are dispersed or dissolved according to the conditions, a liquid containing a cement additive (a thickener) and a liquid containing a cement water-reducing agent, or a cement additive (a thickener) It is desirable to add and knead at least one cement at a time with cement, fine aggregate and coarse aggregate.

As described above, in the method for preparing the cement composition of the present invention, a cement water reducing agent, preferably a cement water reducing agent and a cement additive (thickening agent) are dispersed or dissolved in a part or the whole of the kneading water in advance. Preliminarily, the cement water reducing agent (and also a cement additive (thickener))
By adding the kneading water containing into the mixing system, the kneading water has a feature in that it can be kneaded in a very short time, and for other requirements, a conventionally known preparation method can be applied as it is. It is.

Hereinafter, a preferred method of preparing the cement composition of the present invention will be described in more detail with reference to the flow charts outlining the procedures of each embodiment of the preparation method of the present invention shown in FIGS. 1 (b) to 1 (d). Although described in detail, it goes without saying that the present invention is not limited to these specific embodiments.

As one specific embodiment of the method for preparing a cement composition according to the present invention, as shown in FIG. 1 (b), (1) fine aggregates such as cement and sand are mixed appropriately. Into the inside (for example, in a mixer) and knead it. Thereby, the fine aggregate and the cement are uniformly mixed.

(2) A kneading water obtained by dispersing or dissolving a cement water reducing agent and a cement additive in a part or the whole amount is introduced into the mixture of fine aggregate and cement prepared by the above-mentioned kneading in (1). Knead. By the kneading, a uniform mortar is prepared.

(3) Next, coarse aggregate such as gravel is put into a mixing system (in the mortar prepared by kneading in (2) above) and further kneaded. By this kneading, uniform concrete is prepared.

In this embodiment, in the kneading step (2), a cement water reducing agent and a cement additive are dispersed or dissolved in kneading water in a part or the whole amount, and the kneading water containing the cement water reducing agent and the cement additive is added. Is an example of a material having a feature in that kneading can be performed in a very short time by introducing the.

Next, as another embodiment of the method for preparing the cement composition according to the present invention, as shown in FIG. 1C, (1) fine aggregate such as cement and sand is appropriately It is put into a mixing system (for example, in a mixer) and kneaded. Thereby, the fine aggregate and the cement are uniformly mixed.

(2) The cement additive-containing liquid and the cement water-reducing agent-containing liquid obtained by separately dividing the cement additive and the cement water-reducing agent and dispersing or dissolving them in a part of the kneading water are subjected to the empty kneading of (1). The mixture is charged into the prepared mixture of fine aggregate and cement and kneaded. By the kneading, a uniform mortar is prepared.

(3) The coarse aggregate such as gravel is put into a mixing system (in the mortar prepared by the kneading in the above (2)) and further kneaded. By this kneading, uniform concrete is prepared.

In this embodiment, in the kneading of (2), the cement water reducing agent and the cement additive are dispersed or dissolved in a part of the kneading water, respectively. This is an example of a material having a feature in that it can be kneaded in a very short time by being charged.

Next, still another embodiment of the method for preparing a cement composition according to the present invention is as follows: (1) Cement admixture containing fine aggregate such as cement and sand and a solid cement additive Is put into a suitable mixing system (for example, in a mixer) and kneaded. Thereby, the cement, the fine aggregate and the thickener are uniformly mixed.

(2) Mixing a kneading water obtained by dispersing or dissolving a cement water reducing agent in a part or the whole amount with the cement prepared by the empty kneading of (1) above, a cement containing fine aggregate and a solid cement additive. Into the mixture with the product and knead. By the kneading, a uniform mortar is prepared.

(3) Next, coarse aggregate such as gravel is put into a mixing system (in the mortar prepared by kneading in (2) above) and further kneaded. By this kneading, uniform concrete is prepared.

In this embodiment, in the kneading of (1),
A cement mixture containing a solid cement additive is further added to the mixture system to prepare a mixture of uniform cement, a fine aggregate, and a cement mixture containing a solid cement additive. In the kneading of 2), the cement water reducing agent can be kneaded in a very short time by dispersing or dissolving the cement water reducing agent in a part or the whole amount of the kneading water and adding the kneading water containing the cement water reducing agent. It is an example of the one having the following.

Next, as still another specific embodiment of the method for preparing a cement composition according to the present invention, as shown in FIG. The aggregate is put into a suitable mixing system (for example, in a mixer) and kneaded. Thereby, the cement and the fine aggregate are uniformly mixed.

(2) A cement additive-containing liquid obtained by dispersing or dissolving a cement additive in a part of kneading water is poured into the mixture of cement and fine aggregate prepared by the above-mentioned (1) kneading. And knead. A mortar is prepared by the kneading.

(3) Next, a liquid containing the cement water reducing agent obtained by dispersing or dissolving the cement water reducing agent in a part of the kneading water is placed in a mixed system (in the mortar prepared by kneading in (2) above).
And further kneaded. A uniform mortar is prepared by the kneading.

In this embodiment, in the kneading of (2), a cement additive-containing liquid obtained by dispersing or dissolving the cement additive in a part of the kneading water is charged and kneaded. This is an example of a material having a feature in that a cement water reducing agent-containing liquid obtained by dispersing a cement water reducing agent in a part of kneading water can be kneaded in a short time.

In this embodiment, from the introduction of the liquid containing the cement additive (thickener) in the kneading step of (2), (3)
The time required until the introduction of the liquid containing the cement water reducing agent in the kneading step is preferably 5 to 30 seconds. If the charging interval is less than 5 seconds, sufficient kneading is not achieved,
That is to say, it is consistent with the preparation method of the other embodiments described above, and if it exceeds 30 seconds, the kneading time,
In particular, the time required to prepare a uniform mortar is slightly reduced.

[0092] Although the principle of operation that the kneading time can be extremely shortened by each of the above embodiments is not clear, contrary to the embodiment shown in Fig. 1 (d) described above, in the kneading of (2). Then, a liquid containing a cement water reducing agent obtained by dispersing or dissolving a cement water reducing agent in a part of the kneading water in advance is added and kneaded, and in the subsequent kneading (3), the cement additive (thickener) is kneaded in advance. When a liquid containing a cement additive (thickener) that is dispersed or dissolved in a part of the mixture is added and kneaded, the kneading time as described above, particularly the time until a uniform mortar is prepared, cannot be shortened. In view of the results, if the dispersant adsorbed first on the cement particles is replaced by the cement additive (thickener) added later,
It is considered that the mortar thickens at a stretch and the kneading time is required.

Next, in each of the above-described embodiments, the kneading step can be performed without performing the idle kneading step. In this case, however, cement or bone is previously placed in the mixing system (for example, in the mixer). After the composition components such as cement are added, kneading water containing a cement admixture such as a cement water reducing agent may be added and kneaded, or the composition such as cement or aggregate and a cement water reducing agent may be added. And kneading water containing the cement admixture may be put into a mixing system (for example, in a mixer) at a time and kneaded.

[0094] Further, coarse aggregate and fine aggregate are previously charged with cement as the aggregate, kneaded by kneading if necessary, and kneading is performed by adding kneading water containing a cement admixture such as a cement water reducing agent. May be. Thereby, the preparation of the mortar and the preparation of the concrete in each of the above embodiments are reduced by one.
It can be performed in the process, and the process can be simplified. In particular, all of the composition components used, that is, a composition such as cement, an aggregate (coarse aggregate and fine aggregate) and a cement admixture excluding a cement water reducing agent, and a kneading water containing a cement water reducing agent and the like are used. At the same time, it can be put into a mixing system (for example, in a mixer) that does not contain any of cement, fine aggregate and coarse aggregate and kneaded, and in this case, only one kneading step is required. A desired cement composition can be prepared, and the process can be further simplified.

The method for preparing the cement composition according to the present invention is not limited to the method of preparing concrete as shown in FIGS. 1B and 1C, but also the mortar shown in FIG. It can be applied to the preparation of paste. In this case, in each embodiment shown in FIGS. 1 (b) and (c) described above, the final step, that is, the step of charging the coarse aggregate into the mortar and kneading it, is a preceding step. It can be used for the preparation of a mortar, and can be used for the preparation of a cement paste to be used in the first step using only cement in the first step up to the preparation step of the next step. It can be appropriately selected from those described. Similarly, in addition to the preparation of the mortar and cement shown in FIG. 1 (d), the preparation of concrete can also be performed by appropriately performing the final steps shown in FIGS. 1 (b) and (c). Can be appropriately selected from those already described.

In the above-mentioned mixing system, means (apparatus) for adding kneading water to these compositions and kneading them include the ability to knead cement and aggregate, etc. It is not particularly limited as long as it has the ability to sufficiently mix and knead kneading water or coarse aggregate containing a cement water reducing agent or a cement additive as an ingredient. Various mixers (mixers) used for the preparation of cement compositions such as concrete can be applied as they are, for example, a pan-type forced kneading mixer, a horizontal single-shaft type, a horizontal twin-shaft type, a drum type, A tilted cylinder type, a continuous mixer, or the like can be used.

[0097]

EXAMPLES Examples of the present invention will be shown below, but these are given for illustrative purposes and do not limit the spots of the present invention. In the following, parts and% are parts by weight,
It represents% by weight.

(1) Production Method of Cement Additive (Thickener) Example 1 A flask equipped with two dropping funnels, a stirrer, a nitrogen inlet tube, a thermometer and a cooler was charged with 327 parts of ion-exchanged water and Hytenol N. -08 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was charged, and Hytenol N-08 was completely dissolved at 72 ° C under stirring. Nitrogen was gently flowed at an internal temperature of 72 ° C., and the inside of the flask was replaced with nitrogen. After sufficient nitrogen substitution, methacrylic acid 105 prepared in advance was dropped from the dropping funnel.
Parts, 97.5 parts of methyl acrylate, 9 ethyl acrylate
7.5 parts, 1.6% hytenol N-08 aqueous solution 300
30 parts of the pre-emulsion mixture obtained by vigorously stirring the parts were added and stirred for 5 minutes. Next, 1 part of a 5% aqueous solution of sodium hydrogen sulfite and 4 parts of a 1% aqueous solution of ammonium persulfate were added, and stirring was continued for 20 minutes while maintaining the internal temperature at 72 ° C. to perform initial polymerization. The remaining 570 parts of the pre-emulsion mixture and 64 parts of 1% ammonium persulfate were added dropwise thereto over 2 hours. After the completion of the dropwise addition, the temperature was raised to 80 ° C., and stirring was continued for 1 hour, followed by cooling to complete the polymerization, thereby obtaining an aqueous resin dispersion (1) having a nonvolatile content of 30.8%.

Example 2 In place of the pre-emulsion mixture described in Example 1, 75 parts of methacrylic acid, 120 parts of methyl acrylate, 105 parts of ethyl acrylate and 300 parts of a 1.6% aqueous solution of hytenol N-08 were added. The same procedure as in Example 1 was repeated except that the pre-emulsion mixture obtained by stirring was used.
A 0.9% aqueous resin dispersion (2) was obtained.

Comparative Example 1 A flask equipped with two dropping funnels, a stirrer, a nitrogen inlet tube, a thermometer and a cooler was charged with 327 parts of ion-exchanged water and 4 parts of Hytenol N-08 (Daiichi Kogyo Seiyaku Co., Ltd.). Was added, and Hytenol N-08 was completely dissolved at 72 ° C under stirring. Nitrogen was gently flowed at an internal temperature of 72 ° C., and the inside of the flask was replaced with nitrogen. After sufficient nitrogen substitution, methacrylic acid 105 prepared in advance was dropped from the dropping funnel.
195 parts of ethyl acrylate, and 300 parts of a 1.6% aqueous solution of hytenol N-08, 30 parts of the pre-emulsion mixture obtained by vigorous stirring were added, and the mixture was stirred for 5 minutes. Next, 1 part of a 5% aqueous sodium sulfite solution and 4 parts of a 1% ammonium persulfate aqueous solution were added, and stirring was continued for 20 minutes while keeping the internal temperature at 72 ° C. to carry out initial polymerization. The remaining 570 parts of the pre-emulsion mixture and 64 parts of 1% ammonium persulfate were added dropwise thereto over 2 hours. After completion of the dropwise addition, the temperature was raised to 80 ° C., and stirring was continued for 1 hour, followed by cooling to complete the polymerization, thereby obtaining a comparative aqueous resin dispersion (1) having a nonvolatile content of 30.8%.

Comparative Example 2 In place of the pre-emulsion mixture described in Comparative Example 1, 120 parts of methacrylic acid, 72 parts of methyl acrylate, 108 parts of ethyl acrylate and 300 parts of a 1.6% aqueous solution of hytenol N-08 were added. The same operation as in Comparative Example 1 was carried out except that the pre-emulsion mixture obtained by stirring was used.
0.8% of a comparative aqueous resin dispersion (2) was obtained.

Table 1 below shows, for confirmation, the monomer compositions used for producing the aqueous resin dispersions obtained in Examples 1 and 2 and Comparative Examples 1 and 2 and the comparative aqueous resin dispersions. And displayed together.

[0103]

[Table 1]

(2) Addition of cement obtained in (1) above
COMPOSITION USING CEMENT ADDITIVE CONTAINING PERFORMANCE
(Concrete) Preparation Method Examples 3-4 and Comparative Examples 3-4 Ordinary Portland cement (Chichibu Onoda Cement, specific gravity 3.16) as cement, and Oigawa-based land sand (specific gravity 2.62, FM2. 71), Hard sandstone crushed stone from Ome (specific gravity 2.64, MS 20 mm) was used as coarse aggregate.

As a cement water reducing agent, a naphthalenesulfonic acid formalin condensate (manufactured by Kao Corporation, Mighty 150) commercially available as a cement dispersant was used.
% By weight of cement and used as a cement additive (hereinafter also referred to as a thickener) in Examples 1-2.
And the aqueous resin dispersions (1) obtained in Comparative Examples 1 and 2.
(2) and comparative aqueous resin dispersions (1) and (2) were used, respectively. In order to adjust the amount of air, a commercially available antifoaming agent was used.

The compounding conditions of the cement composition (here, concrete) were such that the unit cement amount was 500 kg / m ³ ,
The unit water amount was 165 kg / m ³ and the fine aggregate ratio was 45%.

Concrete was prepared according to the following procedure under the conditions of mixing the above-mentioned raw materials and cement composition (here, concrete).

(1) 44.2 kg of fine aggregate and 25.0 kg of ordinary Portland cement were put into a 50 liter pan-type forced kneading mixer and kneaded for 10 seconds.

(2) Kneading water containing a cement dispersant and a cement additive (thickener) in the amounts shown in Table 2 below.
11 kg was added to the fine aggregate / cement prepared in the above (1) and kneaded, and the time until the mortar became uniform was measured. The mortar became uniform at the kneading times shown in Table 2 below. After the mortar became uniform, kneading was further continued for 30 seconds each.

(3) Thereafter, 44.2 kg of the coarse aggregate was charged into the mortar prepared in the above (2), and kneaded for 90 seconds to produce each concrete.

(3) Evaluation of Concrete Performance Slump value and flow value were measured for each of the concretes manufactured according to the procedures shown in (1) to (3) of the above concrete preparation method.

-Measurement Method- The slump value and the flow value are measured according to Japanese Industrial Standards (J
IS A 1101, 1128).
Table 2 shows the results.

[0113]

[Table 2]

When the aqueous resin dispersions (1) and (2) obtained from Examples 1 and 2 and Comparative Examples 1 and 2 were compared with the comparative aqueous resin dispersions (1) and (2), mortar kneading was performed. The time was 147 seconds in Comparative Example 3 using the comparative aqueous resin dispersion (1), and 165 seconds in Comparative Example 4 using the comparative aqueous resin dispersion (2), whereas the aqueous resin dispersion ( It was confirmed that the kneading time can be significantly reduced to 25 seconds in Example 3 using 1) and 58 seconds in Example 4 using the aqueous resin dispersion (2).

[Brief description of the drawings]

FIG. 1 is a process diagram outlining a procedure for a method for preparing a cement composition according to the present invention. Figure 1
(A) and FIG. 1 (e) are process diagrams outlining the procedure for each embodiment when a conventionally known typical method for preparing concrete or mortar is applied, and FIG. 1 (b)
(D) is a process diagram outlining the procedure for each embodiment when the method for preparing a cement composition according to the present invention is applied.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C04B 111: 00

Claims (12)

[Claims] Claims 1. An alkyl (meth) acrylate-based monomer composed of at least two kinds of methyl acrylate and another alkyl (meth) acrylate as a main component, and the amount of the methyl acrylate is And a cement additive comprising a copolymer obtained by polymerizing a monomer component having an amount equal to or more than that of other alkyl (meth) acrylates. 2. The method according to claim 1, wherein the cement additive comprises at least two or more alkyl (meth) acrylate-based monomers composed of methyl acrylate and another alkyl (meth) acrylate, and (meth) acrylic acid. The cement admixture according to claim 1, comprising a copolymer obtained by polymerizing a monomer component containing 3. A cement admixture comprising the cement additive according to claim 1 and a cement water reducing agent. 4. A cement composition comprising at least the cement admixture according to any one of claims 1 to 3, cement and kneading water. 5. A cement composition characterized in that a cement water reducing agent and the cement additive according to claim 1 or 2 are dispersed or dissolved in a part or the whole amount of the kneading water, and the mixture is kneaded by being charged into a mixing system. Preparation method. 6. The cement additive-containing liquid and the cement water-reducing liquid according to claim 1 or 2, wherein the cement additive and the cement water-reducing agent according to claim 1 or 2 are respectively dispersed or dissolved in a part of the kneading water. A method for preparing a cement composition, characterized by simultaneously introducing and kneading an agent-containing liquid into a mixing system. 7. The cement additive according to claim 1, which is dispersed or dissolved in a part of the mixing water.
Alternatively, the cement additive-containing liquid described in 2 is charged into the mixing system and kneaded, and then the cement water-reducing agent-containing liquid obtained by dispersing or dissolving the cement water-reducing agent in a part of the kneading water is charged and further kneaded. A method for preparing a cement composition, comprising: 8. The mixed system contains cement, cement and fine aggregate, cement,
The cement composition according to any one of claims 5 to 7, wherein the cement composition is in a state containing fine aggregate and coarse aggregate or in a state not containing any of cement, fine aggregate and coarse aggregate. Preparation method. 9. The composition in the mixed system when the mixed system contains cement, cement and fine aggregate, or cement, fine aggregate and coarse aggregate. The method for preparing a cement composition according to claim 8, wherein the material component is kneaded. 10. The water reducing agent for cement according to claim 5, wherein the mixed system does not contain any of cement, fine aggregate and coarse aggregate. Kneading water in which the cement additive according to 1 or 2 is dispersed or dissolved, the cement additive-containing liquid and the cement water-reducing agent-containing liquid according to claim 1 or 2, or the cement additive according to claim 1 or 2. The cement composition according to any one of claims 4 to 6, wherein a liquid containing the cement, at least cement among cement, fine aggregate and coarse aggregate is put into the mixing system at a time and kneaded. Preparation method. 11. The method for preparing a cement composition according to claim 5, wherein the mixed system contains at least one cement admixture excluding a cement water reducing agent. 12. A method for preparing a cement composition according to claim 11, wherein the cement admixture other than the cement water reducing agent contains a solid cement additive according to claim 1 or 2.