JPH10167784A - Reducing agent for water separation of cement composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a reducing agent for water separation for a cement composition, capable of sufficiently reducing the separated water while maintaining excellent fluidity for the cement composition such as a mortar or a concrete and manifesting remarkable reducing effects on the water separation even with a small amount added thereof. SOLUTION: This reducing agent for water separation comprises at least either one of an aluminate and a silicate and a water absorbing resin and further preferably a water-soluble resin. A water absorbing resin having a liquid absorption ratio for cement water within the range of 5-100g/g is preferred as the water absorbing resin and, e.g. an acrylic or a methacrylic ester-based cross-linked polymer is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement composition containing cement and water, such as concrete and mortar, which is used for reducing the amount of water separated from cement in the cement composition. The present invention relates to a water separation reducing agent for a cement composition to be used.

[0002]

2. Description of the Related Art In general, when a cement composition such as concrete or mortar is prepared by kneading water with a cement material such as cement or aggregate, a part of the kneading water is obtained by placing the cement composition. Separation from the cement, sedimentation of other components such as aggregates and cement particles, and bleeding on the upper surface of the cement composition, that is, bleeding occurs.

When this bleeding occurs, the strength of the hardened cement composition is reduced. Also,
Since bleeding causes material separation, the fluidity of the cement composition is reduced, and workability (workability) is reduced.
Gets worse.

Therefore, conventionally, when kneading water with a cement material to prepare a cement composition, a separated water reducing agent has been used to reduce the amount of water separated from the cement. As the separation water reducing agent for the cement composition, a natural water-soluble resin such as a polysaccharide polymer or a water-soluble cellulose ether, or a synthetic water-soluble resin such as a polyacrylamide-based water-soluble resin has been put to practical use. I have.

[0005] However, these water-soluble resins are expensive, and in order to sufficiently reduce the separated water in the cement composition and obtain good results, it is necessary to increase the amount of the added water. Cannot be reduced efficiently. In addition, natural water-soluble resins such as polysaccharide polymers and water-soluble cellulose ethers may be spoiled.

[0006] Calcium aluminate (JP-A-51-44117) and sodium aluminate (JP-A-1-13396) are used as a separating water reducing agent for a cement composition.
No. 5) or a silicate such as an aluminate such as magnesium silicate (Japanese Patent Application Laid-Open No. 54-145147) and sodium silicate (Japanese Patent Application Laid-Open No. 56-169160). Use is also being considered.

However, these aluminates and silicates need to be added in large amounts in order to sufficiently reduce the separated water in the cement composition and obtain good results. Cannot efficiently reduce the water separation. These aluminates and silicates also reduce the slump value of the cement composition. That is, the fluidity of the cement composition decreases. Furthermore, especially in the case of a high addition amount, the hardening of the cement composition is promoted, and the workability is reduced.

Further, Japanese Patent Application Laid-Open No. 51-44117 discloses a cement composition containing Portland cement, calcium aluminate (calcium aluminate), an inorganic sulfate, an inorganic lightweight body, and a water-soluble polymer substance. Is disclosed. JP-A-56-169160 discloses a cement composition in which a specific admixture and a water-soluble polymer substance are added to cement, water, and sodium silicate (sodium silicate). .

[0009]

However, as described above, even when a water-soluble resin and calcium aluminate or a water-soluble resin and sodium silicate are used in combination in the cement composition, each of them is used alone. Although some improvement is seen in comparison with the case of using in the above, the above-mentioned problems of water-soluble resin and aluminate (silicate), that is, the separation water is efficiently reduced while maintaining excellent fluidity. The fact is that the problem of not being able to do so has not been resolved.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a cement composition such as mortar or concrete with a sufficient flow of separated water while maintaining excellent fluidity. Another object of the present invention is to provide a separation water reducing agent for a cement composition which can significantly reduce the separation water even with a small amount of addition.

[0011]

Means for Solving the Problems The present inventors have intensively studied a separation water reducing agent in order to solve the above-mentioned problems. As a result, in the separation water reducing agent of the cement composition containing at least one of aluminate and silicate,
In addition, by incorporating a water-absorbent resin, it is possible to sufficiently reduce the amount of separated water while maintaining excellent fluidity for cement compositions such as mortar and concrete. And found that the present invention was completed.

The water separation agent for a cement composition according to the first aspect of the present invention comprises at least one of an aluminate and a silicate and a water-absorbing resin in order to solve the above-mentioned problems. And

According to the above construction, at least one of an aluminate and a silicate is dissolved in water in the cement composition to increase the viscosity of the cement composition, and the water-absorbing resin is used in the cement composition. By absorbing the water in the material, it is possible to efficiently reduce the separated water in the cement composition while avoiding a decrease in the fluidity of the cement composition. This provides a separated water reducing agent that can sufficiently reduce separated water with respect to cement compositions such as mortar and concrete while maintaining excellent fluidity, and that exhibits a remarkable separated water reducing effect even with a small amount of addition. can do.

In order to solve the above-mentioned problems, the agent for reducing separated water of the cement composition according to the second aspect of the present invention further comprises a water-soluble resin in the agent for reducing separated water according to the first aspect. It is characterized by.

[0015] According to the above configuration, the water-soluble resin is dissolved in the water in the cement composition to increase the viscosity of the water, so that the separated water reducing agent can more efficiently reduce the separated water in the cement composition. Can be provided.

[0016] In order to solve the above-mentioned problems, the separation water reducing agent for a cement composition according to the third aspect of the present invention has the first aspect.
Or the separation water reducing agent according to 2, wherein the water-absorbent resin has a liquid absorption ratio to cement water of 5 to 100 g / g.
Is within the range.

According to the above configuration, since the water-absorbing resin absorbs water in the cement composition more efficiently, there is provided a separated water reducing agent which can more efficiently reduce the separated water in the cement composition. can do.

Hereinafter, the present invention will be described in detail. The separation water reducing agent of the cement composition according to the present invention comprises at least one of an aluminate and a silicate, and a water-absorbing resin.

The above-mentioned water-absorbing resin may be any resin that has water-absorbing properties and is insoluble in water, but the liquid-absorbing ratio to cement water is in the range of 5 to 100 times (g / g). Is more preferable. Thereby, the separation water reducing agent can more efficiently reduce the separation water of the cement composition. Further, it is more preferable that the water absorbing resin has a water absorption ratio to pure water of 50 to 1000 times. The term “cement water” refers to a filtrate obtained by filtering a mixed solution consisting of 99 parts by weight of pure water and 1 part by weight of cement.

As the above water-absorbing resin, specifically,
Various crosslinked polymers can be used, for example, polyacrylate-based crosslinked polymer, isobutylene-maleic acid crosslinked copolymer, starch-acrylic acid crosslinked graft polymer, vinyl alcohol-acrylic acid crosslinked copolymer, Vinyl alcohol crosslinked polymer, polyalkylene glycol crosslinked polymer, starch-acrylonitrile crosslinked copolymer, vinylpyrrolidone crosslinked polymer, sulfonic acid group-containing crosslinked polymer, N-
Examples include a vinylamide-based crosslinked polymer, a (meth) acrylate-based crosslinked polymer, and a (meth) acrylamide-based crosslinked polymer.

Among the water-absorbing resins exemplified above, a sulfonic acid group-containing crosslinked polymer, an N-vinylamide-based crosslinked polymer,
(Meth) acrylate crosslinked polymer, and
(Meth) acrylamide crosslinked polymer is more preferable,
N-vinylamide-based crosslinked polymers and (meth) acrylate-based crosslinked polymers are more preferred, and (meth) acrylate-based crosslinked polymers are most preferred.

The above N-vinylamide crosslinked polymer is
It is a crosslinked polymer obtained by copolymerizing monomer components containing N-vinylamides. As the N-vinylamides,
For example, the general formula (1)

[0023]

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(Wherein R ₁ and R ₂ each independently represent a hydrogen atom or a methyl group), and more specifically, for example, N-vinylformamide, N-vinylformamide, -Vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide and the like, but are not particularly limited. These N-vinylamides may be used alone or in combination of two or more. Among the N-vinyl amides exemplified above, N-vinyl acetamide is particularly preferred. Further, N-vinylamides and the following (meth) acrylates may be used in combination.

The (meth) acrylic ester-based crosslinked polymer is a crosslinked polymer obtained by copolymerizing (or polymerizing) a monomer component containing (meth) acrylic esters. As the (meth) acrylates, for example, those represented by the general formula (2)

[0026]

Embedded image

(Wherein, R represents a hydrogen atom or a methyl group, and X represents an oxyalkylene group having 2 to 4 carbon atoms in which the mole fraction of the oxyethylene group to all oxyalkylene groups is 50% or more. , Y represents an alkoxy group having 1 to 5 carbon atoms, a phenoxy group, or an oxyalkylphenyl group having 1 to 3 carbon atoms as a substituent, and n represents an average of 3 to 5 A compound represented by a positive number of 100) is more preferable, and specifically,
For example, methoxy polyethylene glycol mono (meth)
Acrylate, methoxy polyethylene glycol / polypropylene glycol mono (meth) acrylate, methoxy polyethylene glycol / polybutylene glycol mono (meth) acrylate, ethoxy polyethylene glycol mono (meth) acrylate, ethoxy polyethylene glycol / polypropylene glycol mono (meth)
Examples include acrylate, ethoxy polyethylene glycol / polybutylene glycol mono (meth) acrylate, phenoxy polyethylene glycol mono (meth) acrylate, and benzyloxy polyethylene glycol mono (meth) acrylate, but are not particularly limited. These (meth) acrylates are
They may be used alone or in combination of two or more. Among the (meth) acrylates exemplified above,
Methoxy (poly) ethylene glycol (meth) acrylate is particularly preferred. Further, (meth) acrylates and the above-mentioned N-vinylamides may be used in combination.

The above-mentioned monomer components include, in addition to N-vinylamides and / or (meth) acrylates,
A monomer copolymerizable with these monomers (hereinafter, referred to as a comonomer) may be contained as necessary. As the comonomer, various compounds can be used and are not particularly limited.

Specific examples of the above-mentioned comonomer include acrylic acid, methacrylic acid, crotonic acid,
And unsaturated monocarboxylic acid monomers such as neutralized products and partially neutralized products thereof; maleic acid, fumaric acid, itaconic acid, citraconic acid, and neutralized products and partially neutralized products thereof; Unsaturated dicarboxylic acid monomers; vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, styrene sulfonic acid, 2- (meth) acrylamido-2-methylpropane sulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meth) ) Unsaturated sulfonic acid monomers such as acrylate, 2-hydroxysulfopropyl (meth) acrylate, sulfoethylmaleimide, 3-allyloxy-2-hydroxypropanesulfonic acid, and neutralized and partially neutralized products thereof ; (Meth) acrylamide, isopropylacrylamide, t-butyl (meth)
Amide monomers such as acrylamide; hydrophobic monomers such as (meth) acrylate, styrene, 2-methylstyrene and vinyl acetate; 2-hydroxyethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate; Polypropylene glycol mono (meth) acrylate, allyl alcohol, polyethylene glycol monoallyl ether, polypropylene glycol monoallyl ether, 3-methyl-3-buten-1-ol (isoprenol), polyethylene glycol monoisoprenol ether, polypropylene glycol monoisoprenol Ether, 3-methyl-2-butene-1-
All (prenol), polyethylene glycol monoprenol ether, polypropylene glycol monoprenol ether, 2-methyl-3-buten-2-ol (isoprene alcohol), polyethylene glycol monoisoprene alcohol ether, polypropylene glycol monoisoprene alcohol ether, N -Methylol (meth) acrylamide, glycerol mono (meth) acrylate, glycerol monoallyl ether,
Hydroxyl-containing unsaturated monomers such as vinyl alcohol; cationic monomers such as dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylamide; and quaternaries thereof; nitriles such as (meth) acrylonitrile Monomer; (meth) acrylamide methanephosphonic acid, (meth) acrylamide methanephosphonic acid methyl ester, 2- (meth) acrylamide-2-
And phosphorus-containing monomers such as methylpropanephosphonic acid. Further, the above unsaturated monocarboxylic acid monomer,
Unsaturated dicarboxylic acid monomers, and neutralized or partially neutralized unsaturated sulfonic acid monomers, the corresponding compound,
It is obtained by neutralization with a monovalent metal, a divalent metal, ammonia, or an organic amine.

These comonomer may be used alone or in combination of two or more. Of these, unsaturated monocarboxylic acid-based monomers, unsaturated sulfonic acid-based monomers, and mixtures thereof are particularly preferred because of their excellent copolymerizability and low cost.

A method for producing the above-mentioned N-vinylamide-based crosslinked polymer and (meth) acrylate-based crosslinked polymer (hereinafter, simply referred to as a crosslinked polymer) will be described below.

In the above crosslinked polymer, the ratio of N-vinylamides and / or (meth) acrylates in the monomer components is more preferably set to 10 mol% or more. That is, it is more preferable that the crosslinked polymer is obtained by copolymerizing a monomer component containing at least 10 mol% of N-vinylamides and / or (meth) acrylates. N- in monomer components
When the proportion of vinylamides and / or (meth) acrylic esters is less than 10 mol%, the obtained crosslinked polymer, that is, the separation water reducing effect of the separation water reducing agent containing a water-absorbing resin, is not effective. It may decrease.

When copolymerizing the monomer components, a solvent can be used. Examples of the solvent include a liquid in which the monomer component can be dissolved, for example, water, and a hydrophilic organic solvent that is uniformly mixed with water. Examples of the organic solvent include lower alcohols having 1 to 4 carbon atoms such as methyl alcohol and ethyl alcohol; lower ketones such as acetone;
N, N-dimethylformamide, dimethylsulfoxide; and the like. These solvents may be used alone or as a mixture of two or more. Among the solvents exemplified above, water is particularly preferred. When two or more solvents are used in combination, the mixing ratio may be appropriately set in consideration of the composition of the above-mentioned monomer components and the like. When the polymerization is carried out by a reversed phase suspension polymerization method (described later),
A hydrophobic organic solvent can be used. The hydrophobic organic solvent is not particularly limited.

The amount of the solvent used, that is, the concentration of the monomer component in the solvent (hereinafter simply referred to as “concentration”) is not particularly limited, but it is easy to control the polymerization reaction, economical, Taking the reaction yield and the like into consideration, the concentration may be set within the range of 20% by weight or more and the saturation concentration or less. If the concentration is less than 20% by weight, the amount of the solvent used becomes excessive, and the economy and the reaction yield may be reduced. If the concentration exceeds the saturation concentration, the polymerization reaction becomes non-uniform, and it becomes difficult to remove the heat of polymerization reaction (heat of polymerization). Therefore, it becomes difficult to control the polymerization reaction.

The monomer component further contains a crosslinking agent. By using a crosslinking agent, the internal crosslinking density of the resulting crosslinked polymer can be controlled to an arbitrary value. Specific examples of the crosslinking agent include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and polyethylene glycol di ( Meta)
In one molecule such as acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol di (meth) acrylate, N, N-methylenebisacrylamide, triallyl isocyanurate, and trimethylolpropane diallyl ether A compound having two or more ethylenically unsaturated groups; ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, polyglycerin, propylene glycol, diethanolamine, triethanolamine, polypropylene glycol, polyvinyl alcohol, pentaerythritol, sorbit, Polyhydric alcohols such as sorbitan, glucose, mannitol, mannitan, sucrose, glucose, etc .; ethylene Recall diglycidyl ether, glycerin diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl Ether, trimethylolpropane triglycidyl ether,
Polyepoxy compounds such as glycerin triglycidyl ether; and the like. These crosslinking agents may be used alone or in combination of two or more.

The amount of the crosslinking agent used, that is, the proportion of the crosslinking agent in the monomer component is not particularly limited, but is more preferably in the range of 0.001 mol% to 1.0 mol%. . When the proportion of the cross-linking agent is less than 0.001 mol%, the internal cross-linking density of the obtained cross-linked polymer becomes too small, and the cross-linked polymer, that is, the separated water reducing agent containing a water-absorbing resin, is not used. There is a possibility that the effect of reducing separated water is reduced. When the proportion of the crosslinking agent is more than 1.0 mol%, the internal crosslinking density of the obtained crosslinked polymer becomes too high, and the separation water reducing effect of the separation water reducing agent containing the water absorbent resin is reduced. There is a possibility that.

When a polyhydric alcohol is used as a cross-linking agent, the reaction product obtained after the polymerization reaction is heated to 150 ° C.
More preferably, the heat treatment is performed at a temperature of about 250 ° C. Also,
When a polyepoxy compound is used as a cross-linking agent, it is more preferable to heat-treat the obtained reaction product at 50 ° C to 250 ° C after the polymerization reaction.

The above-mentioned crosslinked polymer can be prepared by subjecting a monomer component to, for example, a radical polymerization method using a radical polymerization initiator, a radiation polymerization method, an electron beam polymerization method, or an ultraviolet polymerization method; It can be obtained by performing polymerization using a known polymerization method such as a polymerization method and a reversed-phase suspension polymerization method. Further, polymerization is performed using a so-called casting polymerization method, thin film polymerization method, spray polymerization method, or a polymerization method in which a double-arm type kneader is used as a reactor, and the reaction product is polymerized while being fragmented by the shearing force of the kneader. By doing so, a crosslinked polymer can also be obtained. Further, the polymerization may be performed with stirring or may be performed in a state of standing.

Examples of the above radical polymerization initiator include, for example, hydrogen peroxide; persulfates such as ammonium persulfate, sodium persulfate and potassium persulfate;
2′-azobis (2-amidinopropane) dihydrochloride,
2,2'-azobis (2-methylpropionamidine)
Water-soluble azo compounds such as dihydrochloride and 4,4′-azobis (4-cyanovaleric acid); 2,2′-azobisisobutyronitrile, 2,2′-azobis (4-methoxy-2,4 −
Oil-soluble azo compounds such as dimethylvaleronitrile); organic peroxides such as benzoyl peroxide, lauroyl peroxide, peracetic acid, benzoyl peroxide, cumene hydroperoxide; and the like, but are not particularly limited. Absent. These radical polymerization initiators may be used alone or in combination of two or more.

A redox initiator can also be obtained by using a reducing agent which promotes the decomposition of the radical polymerization initiator in combination and combining the two. Specific examples of the reducing agent include (bis) sulfuric acid (salt) such as sodium bisulfite, L-ascorbic acid (salt), reducing metals (salt) such as ferrous salt, and amines And the like, but are not particularly limited.

In the case of performing the reverse phase suspension polymerization method, examples of the dispersant for dispersing the aqueous solution of the monomer component in a hydrophobic organic solvent include sorbitan fatty acid ester, sucrose fatty acid ester, glycerin fatty acid ester, Glycerin fatty acid esters; cellulose esters such as ethyl cellulose and cellulose acetate; cellulose ethers, α
-A carboxyl group-containing polymer such as an olefin / maleic anhydride copolymer; and the like, but are not particularly limited.

The reaction temperature depends on the composition of the monomer components, the type and combination of the monomer components, the solvent, and the radical polymerization initiator, the amount used, and the like.
A relatively low temperature is preferred so that the molecular weight of the resulting crosslinked polymer is high. The reaction temperature is, for example, 20 ° C.
A temperature in the range of 100 ° C. is preferred. The reaction time is not particularly limited, and may be appropriately set according to the reaction temperature and the like.

The reaction product obtained by the polymerization reaction may be dried using a dryer or the like, if necessary. The drying temperature and the drying conditions may be set so that the dried product, that is, the crosslinked polymer is not deteriorated by heat, and is not particularly limited. Further, the crosslinked polymer, if necessary,
It can also be crushed and pulverized using a crusher such as a meat chopper or a crusher such as a hammer mill or a jet mill to form particles. A crosslinked polymer is obtained by the above production method.

The surface of the crosslinked polymer is subjected to various processes and modifications to improve its physical properties and properties, for example, the permeability and dispersibility of the cement water and the liquid absorption rate. May be. That is, the crosslinked polymer may be subjected to, for example, a surface treatment for introducing a crosslinked structure near the surface of the crosslinked polymer. By performing the above-mentioned surface treatment, the initial liquid absorption speed (liquid absorption speed immediately after the start of liquid absorption) of the crosslinked polymer, that is, the water-absorbent resin, is further increased.

As the surface cross-linking agent used in performing the above-mentioned surface treatment, a compound having two or more functional groups in one molecule that can react with the functional group of the cross-linked polymer is preferable. Specific examples of the surface cross-linking agent include polyhydric alcohols such as glycerin, ethylene glycol, and pentaerythritol; polyepoxy compounds such as ethylene glycol diglycidyl ether; ethylene diamine, diethylene triamine, triethylene tetramine, and tetraethylene pentane. Polyvalent amines such as amine, pentaethylenehexamine and polyethyleneimine; polyvalent aldehydes such as glutaraldehyde and glyoxal; polyvalent metal salts such as (poly) aluminum chloride, magnesium chloride, calcium chloride, aluminum sulfate, magnesium sulfate, calcium sulfate and the like And the like. One of these surface crosslinking agents may be used alone, or two or more thereof may be used in combination.

The amount of the surface cross-linking agent used is not particularly limited, but may be 0.005% by weight or less based on the cross-linked polymer.
It is preferably in the range of 5% by weight. In addition, the treatment method for performing the above-described surface treatment is not particularly limited. For example, after mixing the surface cross-linking agent as it is in the particulate cross-linked polymer or in a state of being dissolved in an appropriate solvent,
Surface treatment may be performed by heating if necessary, and after the crosslinked polymer is dispersed in a hydrophobic organic solvent, a surface crosslinking agent is added to the dispersion, and then, if necessary. Surface treatment may be performed by heating. By the above production method, a crosslinked polymer having a crosslinked structure further introduced near the surface is obtained.

The method for producing the water-absorbent resin is not limited to the above-described method. Further, only one type of water-absorbing resin may be used, or two or more types may be used in combination.

The agent for reducing separated water according to the present invention comprises the above-mentioned water-absorbing resin and at least one of aluminate and silicate. The above-mentioned aluminate is not particularly limited, and examples thereof include an alkali metal aluminate such as sodium aluminate and an alkaline earth metal aluminate such as calcium aluminate.
As the aluminate, among the above examples, an alkali metal aluminate is more preferred, and sodium aluminate is most preferred.

The silicate is not particularly restricted but includes alkali metal silicates such as sodium silicate and alkaline earth metal silicates such as magnesium silicate. As the silicate, among the above examples, an alkali metal silicate is more preferred, and sodium silicate is most preferred. When one of aluminate and silicate is used, it is more preferable to use aluminate.

The total amount of the aluminate and the silicate used is 20 to 100 parts by weight based on 100 parts by weight of the water-absorbing resin.
It is more preferably within the range of 0 parts by weight,
More preferably, it is within the range of 00 parts by weight. When the total amount of the aluminate and the silicate is out of the above range, the effect of the separation water reducing agent on the cement composition for reducing the separation water may be reduced.

The agent for reducing separated water according to the present invention further comprises:
It is desirable to include a water-soluble resin. Thereby, the effect of reducing the separated water of the cement composition can be further improved.

The above water-soluble resin is easily soluble in water,
Any resin that can increase the viscosity of water by dissolving in water may be used. Further, the water-soluble resin is more preferably a weight average molecular weight (M _W) is 100,000 or more, and more preferably a weight average molecular weight (M _W) is 200,000 or more.

As the above water-soluble resin, specifically,
A linear polymer can be used, and polysaccharide polymers such as β-1,3-glucan and alginic acid; cellulose-based water-soluble resins such as water-soluble cellulose ether, methylcellulose, carboxymethylcellulose, hydromethylcellulose and hydroxypropylmethylcellulose Polyacrylamide-based water-soluble resin; polyvinyl alcohol;
Polyacrylic acid; polyacrylate; protein; starch and the like.

The amount of the water-soluble resin is preferably in the range of 5 to 300 parts by weight, more preferably in the range of 20 to 100 parts by weight, based on 100 parts by weight of the water absorbent resin. More preferred. If the amount of the water-soluble resin is outside the above range, the effect of the separation water reducing agent on the cement composition for reducing the separation water may be reduced.

Further, the total amount of the aluminate and the silicate used is 20 to 1 with respect to 100 parts by weight of the water absorbent resin.
000 parts by weight, and the amount of the water-soluble resin used is in the range of 5 to 300 parts by weight with respect to 100 parts by weight of the water-absorbent resin, whereby the separated water of the separated water reducing agent with respect to the cement composition is reduced. The reduction effect can be further improved.

As described above, the separation water reducing agent according to the present invention has a structure containing at least one of an aluminate and a silicate, and a water-absorbing resin. The separated water reducing agent can sufficiently reduce separated water while maintaining excellent fluidity with respect to a cement composition such as mortar or concrete, and exhibits a remarkable separated water reducing effect even with a small amount of addition.

Next, a method of using the separated water reducing agent according to the present invention will be described. The separated water reducing agent according to the present invention is used by being added to a cement composition containing cement and water. The cement composition may be a composition containing cement and water, and examples thereof include concrete, mortar, cement paste, and the like. still,
The cement composition will be described in detail later.

The amount of the separated water reducing agent to be added to the cement composition is determined so that a desired separated water reducing effect can be ensured according to the type of cement, the composition of the separated water reducing agent, the use of the cement composition and the working conditions. , But more preferably within a range of 0.02 to 1 part by weight based on 100 parts by weight of cement.

When the added amount of the separation water reducing agent is less than 0.02 parts by weight, the separated water of the cement composition cannot be reduced sufficiently, and the physical properties such as the strength of the cured cement composition cannot be reduced. May decrease. If the amount of the water-absorbing resin is more than 1 part by weight, there is a possibility that the fluidity is reduced and the workability is deteriorated, or various physical properties of the cement composition are reduced. It should be noted that the amount of the separated water reducing agent added when water is used by mixing the separated water reducing agent does not include the amount of water.

The amount of the water-absorbing resin added is 0.01 to 0.5 part by weight with respect to 100 parts by weight of cement, and the amount of at least one of aluminate and silicate is added to 100 parts by weight of cement. More preferably, it is 0.01 to 1 part by weight. The amount of water absorbent resin added,
By setting the addition amount of at least one of the aluminate and the silicate within the above range, the separated water of the cement composition can be sufficiently reduced.

Next, the cement composition to which the separation water reducing agent is added will be described. The cement composition comprises cement and water, and further, if necessary, fine aggregate,
Contains coarse aggregate, admixture, etc. As the above-mentioned cement, various known cements can be adopted, and it is not particularly limited, but those conforming to JIS standards are more preferable. Specifically, for example, ordinary Portland cement, ordinary Portland cement (low-alkali type), early-strength Portland cement, early-strength Portland cement (low-alkali type), ultra-high-strength Portland cement, ultra-high-strength Portland cement (low-alkali type) ), Moderate heat Portland cement, moderate heat Portland cement (low alkali type), sulfate resistant Portland cement,
Portland cement such as sulfate-resistant Portland cement (low alkali type); blast furnace cement such as blast furnace cement A, blast furnace cement B, blast furnace cement C; silica cement A, silica cement B, silica cement C, etc. Silica cement; fly ash cement such as fly ash cement type A, fly ash cement type B, fly ash cement type C; alumina cement; calcium cement; various mixed cements; slag cement; One type of these cements may be used, or two or more types may be appropriately mixed and used.

The amount of water used for the cement may be appropriately set according to the type of the cement, the composition of the separation water reducing agent, the molding method of the cement composition, the application, and the like, and is not particularly limited.

The cement composition desirably contains a cement dispersant as an admixture, in addition to cement and water, in order to increase the fluidity of the cement composition and improve workability. The cement dispersing agent, soluble in water, may be any substance capable to promote dispersion of cement particles to improve the fluidity of the cement composition, but the weight average molecular weight (M _W) of 100,000 More preferably, it is less than.

Examples of the cement dispersant include polycarboxylate cement dispersants; carboxylate cement dispersants such as resinates and oxycarboxylates; polyol composites; lignin sulfonate, melamine sulfonic acid or a mixture thereof. Sulfonic acids (salts) such as a formalin condensate of a salt (hereinafter, an acid or a salt thereof is referred to as an acid (salt)), a formalin condensate of creosote oil sulfonic acid (salt), and a naphthalene sulfonic acid (salt) formalin condensate And a cement dispersant. These cement dispersants may be used alone or as a mixture of two or more.

Among the cement dispersants exemplified above, a polycarboxylic acid cement dispersant is excellent in water reducing performance,
It is particularly preferable because the slump holding performance is good. As a result, a cement composition having excellent fluidity and excellent strength and resistance to freezing and thawing can be obtained.

The polycarboxylic acid cement dispersant is
It is a polymer obtained by polymerizing a monomer component containing an unsaturated carboxylic acid (salt). Examples of the polycarboxylic acid-based cement dispersant include a copolymer of polyethylene glycol monoallyl ether and maleic acid (salt); polyalkylene glycol (meth) allyl ether or polyalkylene glycol (meth) acrylate; A copolymer obtained by copolymerizing a monomer component consisting of a sulfonate and a (meth) acrylate; a copolymer of (meth) acrylamide and (meth) acrylic acid (salt); A copolymer obtained by copolymerizing a monomer component comprising (meth) acrylamide, (meth) acrylic acid ester, and (meth) acrylic acid (salt); polyalkylene glycol vinyl ether or polyalkylene glycol (meth) ) Copolymers of allyl ether and (meth) acrylic acid (salt); polyalkylene Copolymer of glycol (meth) acrylate and (meth) acrylic acid (salt); polymerizing a monomer component containing an unsaturated carboxylic acid (salt) and a monomer having a polyalkylene glycol chain as essential components And the like.

Among the above examples, a copolymer obtained by polymerizing a monomer component containing an unsaturated carboxylic acid (salt) and a monomer having a polyalkylene glycol chain as essential components is preferable. Examples of the unsaturated carboxylic acids (salts) include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, citraconic acid, and neutralized and partially neutralized products thereof. One or more kinds can be used. Examples of monomers having a polyalkylene glycol chain include hydroxyalkyl (meth) acrylates such as hydroxylethyl (meth) acrylate; ethylene glycol mono (meth) acrylate, polyethylene glycol / polypropylene glycol mono (meth) acrylate, and the like. Polyalkylene glycol mono (meth) acrylate; alkoxypolyalkylene glycol mono (meth) acrylate such as methoxypolyethylene glycol mono (meth) acrylate and ethoxypolyethylene glycol mono (meth) acrylate; poly such as ethylene glycol mono (meth) allyl ether Alkoxy polyalkyl such as alkylene glycol mono (meth) allyl ether; methoxy polyethylene glycol mono (meth) allyl ether Glycol mono (meth) allyl ether; polyalkylene glycol monotyl ether such as ethylene glycol monochloro ether; alkoxypolyalkylene glycol monotyl ether such as methoxy polyethylene glycol monotyl ether; and one or more of these. Two or more types can be used. In addition, these polycarboxylic acid cement dispersants,
They may be used alone or as a mixture of two or more.

The content of the cement dispersant in the cement composition is preferably in the range of 0.01 to 1% by weight,
More preferably, it is in the range of 0.02 to 0.7% by weight. When the content of the cement dispersant is less than 0.01% by weight,
The fluidity of the cement composition may deteriorate. Conversely, even if the content of the cement dispersant exceeds 1% by weight,
This is economically disadvantageous because the fluidity of the cement mixture is not improved enough to match the amount used.

The above-mentioned cement composition may further contain various additives as an admixture, if necessary. Examples of the above additives include metal hydroxides such as aluminum hydroxide and magnesium hydroxide; carbonates such as calcium carbonate; rock wool, slag wool,
Fibrous substances such as glass fiber, carbon fiber, ceramic fiber, mineral fiber, plant fiber, animal fiber, synthetic fiber, semi-synthetic fiber, regenerated fiber, etc .; vermiculite; silicon carbide, silica, attapulgite, zonolite, sepiolite, wollastonite Diatomaceous earth, vermiculite, perlite, mica, talc, bentonite, asbestos, asbestos foam, etc., but are not particularly limited. These additives may be used alone or in combination of two or more. In addition, the cement composition containing a fibrous substance as an additive further improves the strength after curing.

The amount of the additive to be used with respect to the cement may be appropriately set according to the type of the cement, the type of the additive, the composition of the separation water reducing agent, the use of the cement composition, and the like, and is not particularly limited. .

The method for adding the separation water reducing agent to the cement composition is not particularly limited. Specifically, for example, (1) a separation water reducing agent, water, and, if necessary, are used. After mixing with other admixtures such as a cement dispersant, a method of adding and mixing cement and aggregates such as fine aggregates and coarse aggregates used as needed, (2) cement, After mixing with aggregates such as fine aggregate and coarse aggregate used as needed, water was mixed with other admixtures such as cement dispersant used as needed to form a slurry. Thereafter, a method of adding a separation water reducing agent and water to the slurry may be used. Among these, the method (2) is more preferable.

As described above, a cement mixture comprising the cement composition and the separated water reducing agent is obtained by adding the separated water reducing agent to the cement composition. Then, by molding and curing the cement mixture, a cement molded article excellent in various physical properties such as strength can be obtained. In addition, the molding method of the cement mixture is not particularly limited, and an optimal method may be adopted according to the use and the like.

[0073]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. Unless otherwise specified, "parts" described in Examples and Comparative Examples indicate "parts by weight",
“%” Indicates “% by weight”.

Example 1 First, a water-absorbing resin was prepared. That is, a thermometer was attached to a jacketed tabletop type kneader having an inner volume of 10 L and lined with an ethylene trifluoride resin, to form a reactor. Warm water was allowed to flow through the jacket. In this reactor,
2,247 parts of methoxypolyethylene glycol monomethacrylate (average number of moles of ethylene oxide added: 9 mol) as (meth) acrylates, 43% aqueous solution of sodium methacrylate as a comonomer 2,
448 parts, 4.74 parts of polyethylene glycol diacrylate as a cross-linking agent, and 741 parts of ion-exchanged water as a solvent were supplied as a reaction liquid.

The proportion of methoxypolyethylene glycol monomethacrylate in the monomer components was 68%, and the proportion of sodium methacrylate was 32%. The ratio of polyethylene glycol diacrylate to the monomer component was 0.07 mol%.

Then, after the inside of the reactor was replaced with nitrogen, warm water of 45 ° C. was passed through the jacket while stirring the reaction solution by rotating the blade of a kneader to cool the reaction solution to 45 ° C.
(Reaction start temperature). Then, 59 parts of a 10% aqueous solution of 2,2′-azobis (2-amidinopropane) dihydrochloride as a radical polymerization initiator was added to the reaction solution to initiate polymerization. Then, after the addition, the mixture is stirred for 20 seconds,
Thereafter, stirring was stopped and the reaction solution was allowed to stand. 2,2'-azobis (2-amidinopropane) based on the monomer component
The proportion of dihydrochloride was 0.15 mol%.

Immediately after the addition of 2,2′-azobis (2-amidinopropane) dihydrochloride, the polymerization reaction was started,
After 4 minutes, the reaction temperature peaked at 85 ° C. During this time, the temperature of the jacket was raised to be equal to the temperature of the reaction solution. Next, put the jacket at 80 ℃
Warm water, and kept for 30 minutes to ripen the hydrogel polymer as a reaction product. After the ripening, the kneader blade was rotated at 40 rpm for 10 minutes to break up the hydrogel polymer. Next, the above kneader was inverted to take out the hydrogel polymer from the reactor.

The hydrogel polymer having a fine particle size thus crushed is put into a hot air circulating dryer, and
Dry at 20 ° C. for 4 hours. Next, the crosslinked polymer, which is a dried product, is mixed with a desktop simple pulverizer (manufactured by Kyoritsu Riko Co., Ltd.).
To obtain a (meth) acrylate crosslinked polymer (hereinafter, referred to as a water-absorbent resin (1)) as a water-absorbent resin.

Next, the liquid absorption capacity of the water-absorbent resin (1) with respect to 1% cement water was measured by the following method.
That is, first, 1 part of ordinary Portland cement (manufactured by Tokuyama Corporation) was added to 99 parts of ion-exchanged water, followed by stirring for 2 hours. Then, the obtained mixed solution was 2 Filtration using filter paper provided 1% cement water as a filtrate.

Next, about 0.1 g of the water-absorbent resin (1) was weighed, uniformly placed in a tea bag-type bag, and immersed in 100 g of the above 1% cement water. After 24 hours, the bag was pulled out, drained for a certain period of time, and then the weight W ₁ (g) of the bag was measured. Further, the same operation was performed without using the water-absorbing resin, and the weight W ₀ (g) at that time was measured. And
From these weights W ₁ · W ₀ , the following equation is obtained: liquid absorption capacity (g / g) = (weight W ₁ (g) −weight W
₀ (g)) / weight (g) of water-absorbent resin (1) to calculate the water absorption capacity (g / g). As a result, the liquid absorption ratio of the water absorbent resin (1) was 28 g / g.

Then, 0.315 parts of the water absorbent resin (1),
Sodium aluminate 0.315 as aluminate
, And 63 parts of ion-exchanged water were mixed to obtain a separated water reducing agent according to the present invention.

Next, 1,016 parts of Toyoura standard sand and 630 parts of ordinary Portland cement as cement were charged into a mortar mixer having a capacity of 5 L, and mixed for 30 seconds. Subsequently, 277 parts of ion-exchanged water and 1.89 parts of a polycarboxylic cement dispersant (trade name “FC-900”, manufactured by Nippon Shokubai Co., Ltd.) were added and mixed for 90 seconds.

Next, the above separated water reducing agent was added, and 9
Kneading was performed for 0 seconds to obtain a kneaded material as a cement mixture. The amount of the water-absorbent resin (1) added was 0.05% and the amount of sodium aluminate added was 0.05% based on 100% of ordinary Portland cement.

1,900 g of the obtained kneaded material was transferred to a plastic container having a capacity of 1 L, and allowed to stand for 4 hours.
Measure the weight of water separated from the kneaded material and deposited on the upper surface,
The amount of water separated (bleeding water) of the kneaded product was defined as the amount of bleeding water. Table 1 shows the measurement results together with the composition of the separation water reducing agent.

Example 2 Sodium aluminate 0.3
By performing the same reaction and operation as in Example 1 except that 0.315 part of sodium silicate was used instead of 15 parts, a separated water reducing agent according to the present invention was obtained.

Next, a kneaded product was obtained by performing the same operation as in Example 1 except that the above separated water reducing agent was used. The results of measuring the amount of separated water of the kneaded material in the same manner as in Example 1 are shown in Table 1 together with the composition of the separated water reducing agent.

Example 3 The separated water according to the present invention was obtained by performing the same reaction and operation as in Example 1 except that the amount of sodium aluminate was changed from 0.315 parts to 0.630 parts. A reducing agent was obtained.

Next, a kneaded product was obtained by performing the same operation as in Example 1 except that the above separated water reducing agent was used. The results of measuring the amount of separated water of the kneaded material in the same manner as in Example 1 are shown in Table 1 together with the composition of the separated water reducing agent.

Example 4 The amount of the water-absorbent resin (1) was adjusted to 0.
By carrying out the same reaction and operation as in Example 1 except that the amount of sodium aluminate was changed from 0.315 parts to 0.630 parts while changing the amount of sodium aluminate from 315 parts to 0.630 parts, the present invention was achieved. To obtain a separated water reducing agent.

Next, a kneaded material was obtained by performing the same operation as in Example 1 except that the above separated water reducing agent was used. The results of measuring the amount of separated water of the kneaded material in the same manner as in Example 1 are shown in Table 1 together with the composition of the separated water reducing agent.

Example 5 The amount of the water-absorbent resin (1) was adjusted to 0.
Changed from 315 parts to 0.630 parts, and instead of sodium aluminate 0.315 parts, sodium silicate 0.63 parts
A separation water reducing agent according to the present invention was obtained by performing the same reaction and operation as in Example 1 except that 0 part was used.

Next, a kneaded product was obtained by performing the same operation as in Example 1 except that the above separated water reducing agent was used. The results of measuring the amount of separated water of the kneaded material in the same manner as in Example 1 are shown in Table 1 together with the composition of the separated water reducing agent.

Example 6 First, the same reaction and operation as in Example 1 were performed to obtain a water-absorbing resin (1).
Next, 0.315 parts of the water-absorbing resin (1), a polysaccharide polymer as a water-soluble resin (trade name "Biopoly", manufactured by Takeda Pharmaceutical Co., Ltd., a neutral polysaccharide produced by microorganisms, (Β-1,3-glucan having a number average molecular weight of about 70,000 formed by linearly bonding) 0.126
Part, sodium aluminate 0.3 as aluminate
15 parts and 63 parts of ion-exchanged water were mixed to obtain a separated water reducing agent according to the present invention.

Next, a kneaded product was obtained by performing the same operation as in Example 1 except that the above separated water reducing agent was used. The amount of the water-absorbent resin (1) was 0.05%, the amount of the polysaccharide polymer was 0.02%, and the amount of sodium aluminate was 0.05%, based on 100% of ordinary Portland cement. .

After transferring 1,900 g of the obtained kneaded material to a plastic container having a capacity of 1 L, and allowed to stand for 4 hours,
Measure the weight of water separated from the kneaded material and deposited on the upper surface,
The amount of water separated from the kneaded product was determined. Table 1 shows the measurement results together with the composition of the separation water reducing agent.

Example 7: Sodium aluminate 0.3
The same reaction as in Example 6 except that 0.315 parts of sodium silicate as a silicate was used instead of 15 parts.
By performing the operation and the like, the separated water reducing agent according to the present invention was obtained.

Next, a kneaded product was obtained by performing the same operation as in Example 1 except that the above separated water reducing agent was used. The results of measuring the amount of separated water of the kneaded material in the same manner as in Example 1 are shown in Table 1 together with the composition of the separated water reducing agent.

Example 8 First, the procedure of Example 1 was repeated except that the amount of polyethylene glycol diacrylate was changed from 4.74 parts to 0.47 parts (0.007 mol% based on the monomer component). By performing similar reactions and operations, etc.,
A (meth) acrylic acid ester-based crosslinked polymer (hereinafter, referred to as a water absorbent resin (2)) was obtained. 1% of water absorbent resin (2)
The liquid absorption capacity with respect to the cement water was measured in the same manner as in Example 1, and as a result, was 74 g / g.

Next, except that 0.315 parts of the water-absorbing resin (2) was used instead of 0.315 parts of the water-absorbing resin (1),
By performing the same reaction and operation as in Example 1, the separated water reducing agent according to the present invention was obtained. Further, except for using the above separated water reducing agent, the same operation as kneading in Example 1 was performed to obtain a kneaded product. The amount of water separated from the kneaded material was determined in Example 1.
Table 1 shows the results of the measurement in the same manner as in the above, together with the composition of the separated water reducing agent.

Example 9 First, except that the amount of polyethylene glycol diacrylate was changed from 4.74 parts to 23.7 parts (0.35 mol% based on the monomer component),
By performing the same reaction and operation as in Example 1, a (meth) acrylate-based crosslinked polymer (hereinafter, referred to as water-absorbent resin (3)) was obtained. The liquid absorption capacity of the water-absorbent resin (3) with respect to 1% cement water was measured in the same manner as in Example 1, and as a result, it was 8 g / g.

Next, except that 0.315 part of the water absorbent resin (3) was used instead of 0.315 part of the water absorbent resin (1),
By performing the same reaction and operation as in Example 1, the separated water reducing agent according to the present invention was obtained. Further, except for using the above separated water reducing agent, the same operation as kneading in Example 1 was performed to obtain a kneaded product. The amount of water separated from the kneaded material was determined in Example 1.
Table 1 shows the results of the measurement in the same manner as in the above, together with the composition of the separated water reducing agent.

[0102]

[Table 1]

Comparative Example 1 First, 1,016 parts of Toyoura standard sand and 630 parts of ordinary Portland cement as cement were charged into a mortar mixer having a capacity of 5 L.
Mix for seconds. Subsequently, 277 parts of ion-exchanged water and a polycarboxylic cement dispersant (trade name “FC-900”,
And 1.89 parts of Nippon Shokubai Co., Ltd.) and mixed for 90 seconds.

Next, a mixture of 0.315 parts of sodium aluminate and 63 parts of ion-exchanged water was added as a separation water reducing agent and kneaded for 90 seconds to obtain a kneaded product. Table 2 shows the results in which the amount of separated water of the obtained kneaded product was the same as in Example 1, together with the composition of the separated water reducing agent.

Comparative Example 2 A kneaded product was obtained in the same manner as in Comparative Example 1, except that the amount of sodium aluminate was changed from 0.315 parts to 0.630 parts. The results of measuring the amount of separated water of the kneaded product in the same manner as in Example 1 are shown in Table 2 together with the composition of the separated water reducing agent.

Comparative Example 3 A kneaded product was obtained in the same manner as in Comparative Example 1, except that the amount of sodium aluminate was changed from 0.315 parts to 1.260 parts. The results of measuring the amount of separated water of the kneaded product in the same manner as in Example 1 are shown in Table 2 together with the composition of the separated water reducing agent.

Comparative Example 4 Sodium Aluminate 0.3
A kneaded product was obtained in the same manner as in Comparative Example 1, except that 0.630 part of sodium silicate was used instead of 15 parts. The results of measuring the amount of separated water of the kneaded product in the same manner as in Example 1 are shown in Table 2 together with the composition of the separated water reducing agent.

[Comparative Example 5] Sodium aluminate 0.3
A kneaded material was obtained by performing the same operation as in Comparative Example 1 except that 1.260 parts of sodium silicate was used instead of 15 parts. The results of measuring the amount of separated water of the kneaded product in the same manner as in Example 1 are shown in Table 2 together with the composition of the separated water reducing agent.

[0109]

[Table 2]

Comparative Example 6 First, the same reaction and operation as in Example 1 were performed to obtain a water-absorbing resin (1).
Next, a kneaded product was obtained in the same manner as in Comparative Example 1, except that 0.315 part of the water-absorbent resin (1) was used instead of 0.315 part of sodium aluminate. The result of measuring the amount of separated water of the kneaded material in the same manner as in Example 1,
Table 3 shows the composition of the separation water reducing agent.

Comparative Example 7 First, the same reaction and operation as in Example 1 were performed to obtain a water-absorbing resin (1).
Next, a kneaded product was obtained in the same manner as in Comparative Example 1, except that 0.630 part of the water-absorbent resin (1) was used instead of 0.315 part of sodium aluminate. The result of measuring the amount of separated water of the kneaded material in the same manner as in Example 1,
Table 3 shows the composition of the separation water reducing agent.

Comparative Example 8 First, the same reaction and operation as in Example 1 were performed to obtain a water-absorbing resin (1).
Next, a kneaded product was obtained in the same manner as in Comparative Example 1, except that 1.260 parts of the water-absorbent resin (1) was used instead of 0.315 parts of sodium aluminate. The result of measuring the amount of separated water of the kneaded material in the same manner as in Example 1,
Table 3 shows the composition of the separation water reducing agent.

Comparative Example 9 First, 1,016 parts of Toyoura standard sand and 630 parts of ordinary Portland cement were charged into a mortar mixer having a capacity of 5 L, and mixed for 30 seconds. Subsequently, 277 parts of ion-exchanged water and 1.89 parts of a polycarboxylic cement dispersant (trade name “FC-900”, manufactured by Nippon Shokubai Co., Ltd.) were added and mixed for 90 seconds.

Next, a polysaccharide polymer (trade name “Biopoly”, manufactured by Takeda Pharmaceutical Co., Ltd.) was used as a water separation reducing agent.
A mixture consisting of 0.126 parts, 1.260 parts of sodium aluminate and 63 parts of ion-exchanged water was added, and 90 parts were added.
The mixture was kneaded for 2 seconds to obtain a kneaded material. The results of measuring the amount of separated water of the kneaded material in the same manner as in Example 1 are shown in Table 3 together with the composition of the separated water reducing agent.

[Comparative Example 10] Sodium aluminate
A kneaded product was obtained by performing the same operation as kneading in Comparative Example 9 except that 1.260 parts of sodium silicate was used instead of 260 parts. Table 3 shows the results of measuring the amount of separated water of the kneaded material in the same manner as in Example 1 together with the composition of the separated water reducing agent.
Shown in

Comparative Example 11 First, 1,016 parts of Toyoura standard sand and 630 parts of ordinary Portland cement were charged into a mortar mixer having a capacity of 5 L, and mixed for 30 seconds.
Subsequently, 340 parts of ion-exchanged water and 1.89 parts of a polycarboxylic cement dispersant (trade name "FC-900", manufactured by Nippon Shokubai Co., Ltd.) were added, mixed for 90 seconds, and further mixed for 90 seconds. To obtain a kneaded product. Table 3 shows the results obtained when the amount of separated water in the obtained kneaded product was the same as in Example 1, together with the composition of the separated water reducing agent.

[0117]

[Table 3]

From the comparison between the results of Examples 1 to 5 shown in Table 1 and the results of Comparative Examples 1 to 8 shown in Table 2, the water-absorbent resin according to the present invention and an aluminate or silicate were used. It can be seen that the separated water reducing agent can reduce the amount of separated water of the cement composition more efficiently than the separated water reducing agent consisting only of the water absorbent resin, and the separated water reducing agent consisting only of the aluminate or the silicate. .

Further, the results of Examples 6 and 7 shown in Table 1 and
From the comparison with the results of Comparative Examples 9 and 10 shown in Table 3, the separation water reducing agent comprising the water-absorbent resin, the water-soluble resin, and the aluminate or the silicate according to the present invention shows that the separation water amount of the cement composition It can be seen that the water-soluble resin and the aluminate or silicate can be more efficiently reduced.

[0120]

As described above, the agent for reducing separated water of the cement composition of the present invention has a structure containing at least one of an aluminate and a silicate and a water-absorbing resin.

According to the above structure, the separated water can be sufficiently reduced while maintaining excellent fluidity with respect to the cement composition such as mortar and concrete, and a remarkable separated water reducing effect is exhibited even with a small amount of addition. This has the effect of providing a water separation reducing agent.

Claims (3)

[Claims] An agent for reducing water separation of a cement composition comprising at least one of an aluminate and a silicate, and a water-absorbing resin. 2. The agent for reducing separated water of a cement composition according to claim 1, further comprising a water-soluble resin. 3. The agent for reducing separated water of a cement composition according to claim 1, wherein the water-absorbent resin has a liquid absorbency against cement water in a range of 5 to 100 g / g.