JP6250385B2 - Whitening agent for hydraulic composition - Google Patents

Description

  The present invention relates to a hydraulic composition, a method for producing a hydraulic composition, and a whitening agent for a hydraulic composition.

  There is a growing need for white concrete to make buildings and concrete decorations that you want to have dignity.

White Portland cement is often used for white concrete.
However, there is a problem that white Portland cement is expensive.

  Patent Document 1 discloses a concrete repair mortar in which heavy calcium carbonate fine powder is added and the particle size of the heavy calcium carbonate fine powder is smaller than that of hydraulic cement. It is disclosed that the color tone of the repaired portion in the cast-in-place concrete frame or secondary concrete product and the surrounding concrete can be easily matched at low cost.

  Patent Document 2 uses a dispersant for a hydraulic composition containing an alkyldiethanolamine and a naphthalenesulfonic acid formaldehyde condensate in a specific weight ratio, thereby improving the fluidity retention and early strength of the hydraulic composition. A hydraulic composition dispersant that is compatible is described.

  Patent Document 3 describes a modified hydraulic cement product treated with an aldehyde or an additive containing a substance that can be converted to an aldehyde under the general alkaline conditions of the cement before or during the solidification reaction. .

  Patent Document 4 discloses a water-insoluble polymer (1) having a molecular weight of 500 to 50,000 having a carboxyl group in the molecule and an average particle size of 0.1 to 20 μm, or a heavy polymer having a molecular weight of 500 to 50,000 having a carboxyl group in the molecule. Cement admixture containing one or two or more polymers selected from a water-insoluble metal complex (2) having an average particle diameter of 0.1 to 20 μm obtained from a coalescence and a bivalent or higher metal and a curing accelerator Agents are disclosed, and alkanolamines, low molecular weight aldehydes and polymers thereof are mentioned as curing accelerators.

JP 2011-32143 A JP 2012-121794 A JP 56-45854 A JP-A-2-279546

  However, in the method of Patent Document 1, it takes time and effort to pulverize heavy calcium carbonate and to keep the particle size below a certain level.

  The present invention provides a hydraulic composition that provides a cured product having high whiteness and high strength, for example, a high strength after 24 hours from kneading.

  The present invention relates to a hydraulic powder, an N-alkyldiethanolamine having a linear alkyl group having 1 to 4 carbon atoms [hereinafter referred to as component (a)], and formaldehyde or formaldehyde releasing compound [hereinafter referred to as component (b). The total of the content of the component (a) and the content of the component (b) is 0.05 parts by mass or more and 0.5 parts by mass or less with respect to 100 parts by mass of the hydraulic powder. The invention relates to a hydraulic composition.

The present invention also provides:
N-alkyldiethanolamine having a linear alkyl group having 1 to 4 carbon atoms and formaldehyde or formaldehyde-releasing compound in a total of 0.05 parts by mass or more and 0.5 parts by mass with respect to 100 parts by mass of the hydraulic powder. A step of preparing a hydraulic composition by mixing a part or less, and a step of curing the hydraulic composition to obtain a cured body,
The present invention relates to a method for producing a cured product of a hydraulic composition.

  Moreover, this invention relates to the whitening agent for hydraulic compositions containing N-alkyl diethanolamine which has a C1-C4 linear alkyl group, and formaldehyde or a formaldehyde releasing compound.

  According to the present invention, there is provided a hydraulic composition capable of obtaining a cured product having high whiteness and high strength, for example, a strength after 24 hours from kneading (hereinafter referred to as strength for 24 hours).

The mechanism that exhibits the effects of the present invention is estimated as follows.
Cement usually contains the following components:
C ₃ S: 3CaO · SiO ₂ alite C ₂ S: 2CaO · SiO ₂ belite C ₃ A: 3CaO · Al ₂ O ₃ calcium aluminate C ₄ AF: 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ calcium alumino Ferrite CaSO ₄ : Calcium sulfate Gypsum CaCO ₃ : Calcium carbonate CaO: Calcium oxide MgO: Magnesium oxide

(A) N-alkyldiethanolamine having a linear alkyl group having 1 to 4 carbon atoms as a component promotes the hydration reaction between C ₃ A, C ₄ AF and gypsum, and forms a hydrate called monosulfate Increase the amount of product produced. On the other hand, the formaldehyde or formaldehyde-releasing compound as component (b) acts as a reducing agent in concrete, and it is considered that iron in cement is reduced from trivalent having low solubility to divalent having high solubility. Here, it is known that the whiteness of concrete depends on the amount of iron in the cement. Usually, most of iron in cement remains as unreacted materials, so iron is localized in the concrete. This is one of the causes of darkening. In the present invention, by using the component (a) and the component (b) in combination, iron in the cement is first dissolved by the reducing action, and further incorporated into the monosulfate by the effect of the component (a). It is conceivable that iron in the concrete is uniformly dispersed by these actions, and concrete with higher whiteness is formed.

<(A) component>
The component (a) is N-alkyldiethanolamine having a linear alkyl group having 1 to 4 carbon atoms. The N-alkyldiethanolamine having a linear alkyl group having 1 to 4 carbon atoms is preferably an N-alkyldiethanolamine having an alkyl group having 1 to 3 carbon atoms from the viewpoint of whiteness of the hydraulic composition. N-alkyldiethanolamine having an alkyl group having 1 or 2 carbon atoms is more preferable, and N-alkyldiethanolamine having an alkyl group having 1 carbon atom is still more preferable.

  Specific examples of the N-alkyldiethanolamine having an alkyl group having 1 to 4 carbon atoms as component (a) include N-methyldiethanolamine, N-ethyldiethanolamine, N-propyldiethanolamine, and N-isopropyldiethanolamine. One or more selected compounds may be mentioned, and N-methyldiethanolamine is preferable. (A) A component can use 1 type (s) or 2 or more types.

  The content of the component (a) in the hydraulic composition of the present invention is preferably 0.005 parts by mass or more with respect to 100 parts by mass of the hydraulic powder from the viewpoint of the whiteness of the cured product of the hydraulic composition. 0.01 parts by mass or more is more preferable. Moreover, 0.3 mass part or less is preferable and 0.2 mass part or less is more preferable.

  The content of the component (a) in the hydraulic composition of the present invention is 0.005 parts by mass or more with respect to 100 parts by mass of the hydraulic powder from the viewpoint of the 24-hour strength of the cured product of the hydraulic composition. Preferably, 0.01 mass part or more is more preferable, and 0.02 mass part or more is still more preferable. Moreover, 0.3 mass part or less is preferable, 0.2 mass part or less is more preferable, 0.1 mass part or less is further more preferable, and 0.045 mass part or less is still more preferable.

<(B) component>
The component (b) is formaldehyde or a formaldehyde releasing compound. A formaldehyde-releasing compound is a compound that releases formaldehyde into a hydraulic composition under general alkaline conditions before or during the solidification reaction of the hydraulic composition. The formaldehyde releasing compound may be a compound that produces formaldehyde by self-decomposition. Examples of the component (b) include formaldehyde, hydroxymethanesulfonic acid, melamine formalin resin prepolymer, phenol formalin resin prepolymer, urea formalin resin prepolymer, and the like. From the viewpoint, a compound selected from formaldehyde and hydroxymethanesulfonic acid is preferable, and formaldehyde is more preferable. (B) 1 type (s) or 2 or more types can be used for a component.

  The content of the component (b) in the hydraulic composition of the present invention is preferably 0.005 parts by mass or more with respect to 100 parts by mass of the hydraulic powder from the viewpoint of the whiteness of the cured product of the hydraulic composition. 0.07 parts by mass or more is more preferable, and 0.1 parts by mass or more is more preferable. Moreover, 0.3 mass part or less is preferable and 0.2 mass part or less is more preferable.

  The content of the component (b) in the hydraulic composition of the present invention is 0.005 parts by mass or more with respect to 100 parts by mass of the hydraulic powder from the viewpoint of the 24-hour strength of the cured product of the hydraulic composition. Preferably, 0.01 mass part or more is more preferable, and 0.015 mass part or more is still more preferable. Moreover, 0.3 mass part or less is preferable, 0.2 mass part or less is more preferable, 0.04 mass part or less is further more preferable, and 0.03 mass part or less is still more preferable.

  The content of the component (b) in the hydraulic composition of the present invention is preferably 0.3 parts by mass or less, and 0.2 parts by mass or less with respect to 100 parts by mass of the hydraulic powder from the viewpoint of safety. Is more preferable, 0.1 mass part or less is still more preferable, 0.05 mass part or less is still more preferable, 0.03 mass part or less is still more preferable, 0.02 mass part or less is still more preferable.

<Hydraulic composition>
The hydraulic composition of the present invention contains a hydraulic powder, component (a), component (b), and preferably contains a dispersant, an aggregate, and water.

  Hydraulic powder is a powder that has the property of curing by reacting with water, and a single substance does not have curability, but when two or more types are combined, a hydrate is formed by interaction through water. It is a powder that hardens and hardens. Examples of the hydraulic powder include ordinary Portland cement, early-strength Portland cement, ultra-early-strength Portland cement, mixed cement, and eco-cement (for example, JIS R5214). The hydraulic powder used in the present invention may include gypsum, blast furnace slag, fly ash, silica fume and the like as hydraulic powder other than cement.

  In the hydraulic composition of the present invention, the total content of the component (a) and the content of the component (b) is 0.05 parts by mass or more and 0.5 parts by mass or less with respect to 100 parts by mass of the hydraulic powder. It is. From the viewpoint of the whiteness of the cured product of the hydraulic composition, the total content of the component (a) and the component (b) is 0.05 parts by mass or more with respect to 100 parts by mass of the hydraulic powder. Yes, 0.06 parts by mass or more is preferable, 0.1 parts by mass or more is more preferable, and 0.25 parts by mass or more is more preferable. Moreover, it is 0.5 mass part or less, and 0.3 mass part or less is preferable.

  The total content of the component (a) and the content of the component (b) in the hydraulic composition of the present invention is 100 parts by mass of the hydraulic powder from the viewpoint of the 24-hour strength of the cured product of the hydraulic composition. On the other hand, it is 0.05 mass part or more. Moreover, it is 0.5 mass part or less, and 0.3 mass part or less is preferable.

  In the hydraulic composition of the present invention, the mass ratio of the content of the component (a) to the content of the component (b) is 0.005 or more in terms of the content of the component (a) / the content of the component (b). 15 or less is preferable.

  In the hydraulic composition of the present invention, from the viewpoint of the whiteness of the hydraulic composition, the mass ratio of the content of the component (a) and the content of the component (b) is the content of the component (a) / (b ) Component content of 0.05 or more, preferably 0.1 or more, more preferably 15 or less, more preferably 10 or less, still more preferably 3 or less, and even more preferably 2 or less.

  In the hydraulic composition of the present invention, from the viewpoint of the 24-hour strength of the cured product of the hydraulic composition, the mass ratio of the content of the component (a) and the content of the component (b) is the content of the component (a). The amount / (b) component content is preferably 0.05 or more, more preferably 0.5 or more, and still more preferably 1.0 or more. Moreover, 15 or less is preferable, 10 or less is more preferable, 5 or less is further more preferable, and 2.0 or less is still more preferable.

<Dispersant>
The hydraulic composition of the present invention preferably contains a dispersant. The dispersant is not particularly limited, and examples thereof include lignin-based dispersants, melamine-based dispersants, naphthalene-based dispersants, polycarboxylic acid-based dispersants, and phosphate ester-based dispersants. From the viewpoint of degree, a dispersant selected from naphthalene dispersants and polycarboxylic acid dispersants is preferable, and a dispersant selected from naphthalene dispersants is more preferable.

As a naphthalene-type dispersing agent, naphthalenesulfonic acid formalin condensate is mentioned. The naphthalene sulfonic acid formaldehyde condensate has a weight average molecular weight of preferably 200000 or less, more preferably 100000 or less, still more preferably 80000 or less, and even more preferably 50000 or less, from the viewpoint of fluidity of the hydraulic composition. From the same viewpoint, the weight average molecular weight is preferably 1000 or more, more preferably 3000 or more, further preferably 4000 or more, and still more preferably 5000 or more. The weight average molecular weight of the naphthalenesulfonic acid formaldehyde condensate can be measured by size exclusion chromatography (GPC) under the following conditions.
[GPC conditions]
Standard substance: Polystyrenesulfonic acid Na equivalent Column: G4000SWXL + G2000SWXL (manufactured by Tosoh Corporation)
Eluent: 30 mM acetic acid / acetonitrile = 6/4
Flow rate: 1.0mL / min
Column temperature: 40 ° C
Detector: RI, UV

  Examples of the method for producing a naphthalenesulfonic acid formaldehyde condensate include a method of obtaining a condensate by a condensation reaction of naphthalenesulfonic acid and formaldehyde. You may neutralize the said condensate. Moreover, you may remove the water insoluble matter byproduced by neutralization. Specifically, in order to obtain naphthalenesulfonic acid, 1.2 mol or more and 1.4 mol or less of sulfuric acid is used with respect to 1 mol of naphthalene, and it is 150 ° C. or more and 165 ° C. or less for 2 hours or more and 5 hours or less React to obtain a sulfonated product. Next, formalin is dropped at 85 ° C. or more and 95 ° C. or less over 3 hours or more and 6 hours or less so that the formaldehyde is 0.95 mol or more and 0.99 mol or less with respect to 1 mol of the sulfonated product. After the dropping, the condensation reaction is performed at 95 ° C. or more and 105 ° C. or less. If necessary, water and a neutralizing agent are added to the condensate, and a neutralization step is performed at 80 ° C or higher and 95 ° C or lower. The neutralizing agent is preferably added in an amount of not less than 1.0 mol and not more than 1.1 mol with respect to naphthalenesulfonic acid and unreacted sulfuric acid, respectively. Further, water-insoluble matter generated by neutralization may be removed, preferably separated by filtration. By these steps, an aqueous solution of a naphthalenesulfonic acid formaldehyde condensate water-soluble salt is obtained. This aqueous solution can be used as a naphthalene-based dispersant as it is or with other components added as appropriate. Although the solid content concentration of the aqueous solution depends on the use, the naphthalene dispersant is preferably 30% by mass or more and 45% by mass or less. Further, if necessary, the aqueous solution can be dried and pulverized to obtain a powdery naphthalenesulfonic acid formaldehyde condensate water-soluble salt, which may be used as a powdery naphthalene dispersant. Drying and powdering can be performed by spray drying, drum drying, freeze drying, or the like.

  Examples of the polycarboxylic acid-based dispersant include a polycarboxylic acid-based copolymer. As the polycarboxylic acid copolymer, a copolymer of a monoester of polyalkylene glycol and (meth) acrylic acid and a carboxylic acid such as (meth) acrylic acid (for example, described in JP-A-8-1297 Compounds), copolymers of unsaturated alcohols having polyalkylene glycol and carboxylic acids such as (meth) acrylic acid, copolymers of unsaturated alcohols having polyalkylene glycol and dicarboxylic acids such as maleic acid, etc. Can be used. Here, (meth) acrylic acid means a carboxylic acid selected from acrylic acid and methacrylic acid.

  As a polycarboxylic acid copolymer, a monomer (1) represented by the following general formula (1) and a monomer (2) represented by the following general formula (2) are polymerized. The resulting copolymer [hereinafter referred to as polycarboxylic acid copolymer (I)] can be used.

[Where,
R ¹ , R ² : hydrogen atom or methyl group 1: number of 0 or more and 2 or less m: number of 0 or 1 AO: alkyleneoxy group of 2 or more and 4 or less carbon atoms n: average number of added moles of AO, A number between 5 and 150,
R ^{3 represents a} hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ]

[Where,
R ⁴ , R ⁵ , R ⁶ : hydrogen atom, methyl group, or (CH ₂ ) _m1 COOM ²
M ¹ and M ² : each represents a number of hydrogen atom, alkali metal, alkaline earth metal (1/2 atom), ammonium, alkylammonium, or substituted alkylammonium m1: 0 to 2; Note that (CH ₂ ) _m1 COOM ² may form an anhydride with COOM ¹ . ]

  In general formula (1), AO is preferably an alkyleneoxy group (ethyleneoxy group) having 2 or 3 carbon atoms, more preferably 2 carbon atoms, from the viewpoint of fluidity of the hydraulic composition.

  In general formula (1), n is preferably 9 or more, more preferably 20 or more, still more preferably 50 or more, and even more preferably 70 or more, from the viewpoint of improving the strength of the hydraulic composition after 24 hours. From the viewpoint of the initial fluidity of the hydraulic composition, n is preferably 150 or less, and more preferably 130 or less.

When m is 0, l is preferably 1 or 2. When m is 1, l is preferably 0. From the viewpoint of reactivity during polymerization of the copolymer, m is preferably 1. When m is 0, R ³ is preferably a hydrogen atom from the viewpoint of ease of production of the monomer. When m is 1, R ³ is preferably an alkyl group having 1 to 4 carbon atoms from the viewpoint of ease of production of the monomer, and more preferably a methyl group from the viewpoint of water solubility.

  As the monomer (1), for example, an ester of a polyalkylene glycol and (meth) acrylic acid, an ether obtained by adding an alkylene oxide to an alkenyl alcohol, or the like can be used. Monomer (1) is preferably an ester of polyalkylene glycol and (meth) acrylic acid from the viewpoint of reactivity during polymerization of the copolymer.

  As an ester of polyalkylene glycol and (meth) acrylic acid, an ester of alkylene glycol and (meth) acrylic acid blocked at one end can be used. Specifically, one or more kinds such as methoxypolyethylene glycol acrylate, methoxypolyethylene glycol methacrylate, ethoxypolyethylene glycol acrylate, and ethoxypolyethylene glycol methacrylate can be used. Of these, methoxypolyethylene glycol methacrylate is preferable.

  Further, as an ether in which an alkylene oxide is added to an alkenyl alcohol, an allyl alcohol ethylene oxide adduct or the like can be used. Specifically, an ethylene oxide adduct of methallyl alcohol, an ethylene oxide adduct of 3-methyl-3-buten-1-ol, and the like can be used.

  As a monomer (2), 1 or more types chosen from acrylic acid or its salt, methacrylic acid or its salt, maleic acid or its salt, maleic anhydride, etc. can be used. The monomer (2) is preferably methacrylic acid or a salt thereof from the viewpoint of reactivity during polymerization of the copolymer when m of the monomer (1) is 1. When m is 0, maleic acid or a salt thereof and maleic anhydride are preferred from the viewpoint of reactivity during polymerization of the copolymer.

  In the polycarboxylic acid copolymer (I), the molar ratio of the monomer (1) to the monomer (2) is selected from the viewpoint of improving the initial fluidity of the hydraulic composition. / Monomer (2) is preferably 3/97 or more, more preferably 5/95 or more, further preferably 10/90 or more, and preferably 70/30 or less, more preferably 50/50 or less, 30 / 70 or less is more preferable.

Moreover, the total ratio of the monomer (1) and the monomer (2) in all the monomers contained in the polycarboxylic acid copolymer (I) is an improvement in the initial fluidity of the hydraulic composition. From the viewpoint, 50 mol% or more is preferable, 80 mol% or more is more preferable, 100 mol% or less is preferable, and 100 mol% is more preferable.
The polycarboxylic acid copolymer (I) contains at least one selected from alkyl esters of unsaturated carboxylic acids as constituent monomers other than the monomer (1) and monomer (2). Can be used.

Further, the weight average molecular weight of the polycarboxylic acid copolymer (I) is preferably 10,000 or more, more preferably 35,000 or more, and further preferably 50,000 or more, from the viewpoint of improving the initial fluidity of the hydraulic composition. From the viewpoint of reducing the viscosity of the hydraulic composition, the weight average molecular weight of the polycarboxylic acid copolymer (I) is preferably 100,000 or less, more preferably 80000 or less, and further preferably 70000 or less. This weight average molecular weight is measured by a gel permeation chromatography (GPC) method. For example, it can be measured under the following conditions.
[GPC conditions]
Equipment: High-speed GPC equipment HLC-8320GPC (manufactured by Tosoh Corporation)
Column: G4000PWXL + G2500PWXL (manufactured by Tosoh Corporation)
Eluent: 0.2M phosphate buffer / CH ₃ CN = 9/1
Flow rate: 1.0mL / min
Column temperature: 40 ° C
Detection: Differential refraction detector (RI)
Sample size: 0.5mg / mL
Reference material: Polyethylene glycol equivalent

  When the dispersant is a naphthalene-based dispersant, the content of the dispersant is 0.005 with respect to 100 parts by mass of the hydraulic powder from the viewpoint of improving the fluidity of the hydraulic composition and suppressing curing delay. Part by mass or more is preferable, 0.05 part by mass or more is more preferable, 0.1 part by mass or more is further preferable, 2.5 parts by mass or less is preferable, 1.0 part by mass or less is more preferable, 0.5 More preferred is less than or equal to parts by weight.

  When the dispersant is a polycarboxylic acid-based dispersant, the content of the dispersant is 0 with respect to 100 parts by mass of the hydraulic powder from the viewpoint of improving the fluidity of the hydraulic composition and suppressing curing delay. 0.005 parts by mass or more is preferable, 0.05 parts by mass or more is more preferable, 0.1 parts by mass or more is more preferable, 2.5 parts by mass or less is preferable, 1.0 parts by mass or less is more preferable, 0 0.5 parts by mass or less is more preferable, and 0.2 parts by mass or less is even more preferable.

<Aggregate>
Moreover, the hydraulic composition of this invention can contain an aggregate. Examples of the aggregate include fine aggregate and coarse aggregate. The fine aggregate is preferably mountain sand, land sand, river sand and crushed sand, and the coarse aggregate is preferably mountain gravel, land gravel, river gravel and crushed stone. Depending on the application, lightweight aggregates may be used. The term “aggregate” is based on “Concrete Overview” (published on June 10, 1998, published by Technical Shoin). The hydraulic composition of the present invention preferably contains fine aggregate and coarse aggregate as aggregates. When the hydraulic composition of the present invention is concrete, the amount of coarse aggregate used reduces the expression of the strength of the hydraulic composition and the amount of hydraulic powder such as cement, and can be filled into a formwork or the like. From the viewpoint of improving, the bulk volume is preferably 50% or more, more preferably 55% or more, further preferably 60% or more, more preferably 100% or less, more preferably 90% or less, and still more preferably 80% or less. Further, when the hydraulic composition is concrete, the amount of fine aggregate used is preferably 500 kg / m ³ or more, more preferably 600 kg / m ³ or more, and 700 kg from the viewpoint of improving the filling property to a mold or the like. / M ³ or more is more preferable, 1000 kg / m ³ or less is preferable, and 900 kg / m ³ or less is more preferable. When the hydraulic composition is mortar, the amount of fine aggregate used is preferably 800 kg / m ³ or more, more preferably 900 kg / m ³ or more, still more preferably 1000 kg / m ³ or more, and 2000 kg / m ³ or less. Is preferably 1800 kg / m ³ or less, more preferably 1700 kg / m ³ or less.

  In addition, the hydraulic composition of the present invention includes an AE agent, a retarder, an early strengthening agent, an accelerator, a foaming agent, a thickening agent, a waterproofing agent, an antifoaming agent, a shrinkage reducing agent, a swelling agent, a water-soluble agent. A functional polymer, a surfactant, and the like.

  The hydraulic composition of the present invention preferably contains water. Water / hydraulic powder ratio of the hydraulic composition of the present invention [mass percentage (mass%) of water and hydraulic powder in the slurry, usually abbreviated as W / P, Sometimes abbreviated as W / C. ] Is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, and still more preferably 40% by mass or more. And 60 mass% or less is preferable, and 50 mass% or less is more preferable.

  The hydraulic composition of the present invention may be used for so-called secondary products obtained by casting concrete into a mold and then demolding, or so-called casting after transporting concrete that is not solidified. It may be used for ready-mixed concrete. The cured product of the hydraulic composition of the present invention has a high surface whiteness, and a beautiful product can be obtained.

<Method for producing a cured product of hydraulic composition>
The method for producing a cured product of the hydraulic composition of the present invention comprises:
N-alkyldiethanolamine having a linear alkyl group having 1 to 4 carbon atoms and formaldehyde or formaldehyde-releasing compound in a total of 0.05 parts by mass or more and 0.5 parts by mass with respect to 100 parts by mass of the hydraulic powder. A step of preparing a hydraulic composition by mixing a part or less, and a step of curing the hydraulic composition to obtain a cured body,
Have

  In this invention, from a viewpoint of the whiteness of the hardening body of a hydraulic composition, 0.05 mass part or more of (a) component and (b) component are mixed with respect to 100 mass parts of hydraulic powder. The mixing amount is preferably 0.06 parts by mass or more, more preferably 0.1 parts by mass or more, and further preferably 0.25 parts by mass or more. Moreover, it is 0.5 mass part or less, and 0.3 mass part or less is preferable.

  Moreover, the said mixing amount is 0.05 mass part or more and 0.5 mass part or less with respect to 100 mass parts of hydraulic powder from a viewpoint of 24 hours intensity | strength of the hardening body of a hydraulic composition. 3 parts by mass or less is preferable.

  In the step of preparing the hydraulic composition, it is preferable to mix water, a dispersant, and an aggregate. The above-mentioned thing can be used for these and a preferable aspect is also the same.

In the step of curing the hydraulic composition to obtain a cured body, the mold composition is filled with the hydraulic composition. Carry out curing as needed.
In addition, although the hardened | cured material obtained improves the whiteness of the surface, it does not matter to the extent. Preferably, the whiteness of the surface is 70 or more.

  According to the present invention, N-alkyldiethanolamine having a linear alkyl group having 1 to 4 carbon atoms and formaldehyde or formaldehyde releasing compound in a total of 0.05 parts by mass or more with respect to 100 parts by mass of the hydraulic powder. The manufacturing method of a hydraulic composition which has a process of mixing 0.5 mass part or less and preparing a hydraulic composition is provided. In the step of preparing the hydraulic composition, it is preferable to mix water, a dispersant, and an aggregate. The above-mentioned thing can be used for these and a preferable aspect is also the same.

<Whitening agent for hydraulic composition>
The whitening agent for a hydraulic composition according to the present invention comprises an N-alkyldiethanolamine having a linear alkyl group having 1 to 4 carbon atoms (hereinafter referred to as component (a)) and formaldehyde or formaldehyde releasing compound [hereinafter, (B) component] and a whitening agent for a hydraulic composition that improves the whiteness of a cured product of the hydraulic composition.

  The total content of the component (a) and the content of the component (b) in the whitening agent for a hydraulic composition of the present invention is preferably 5% by mass or more, more preferably 10% by mass or more, and 50 % By mass or less is preferable, and 30% by mass or less is more preferable.

  From the viewpoint of improving the whiteness of the cured product of the hydraulic composition, the whitening agent for the hydraulic composition of the present invention has a mass ratio of the content of the component (a) and the content of the component (b) ( a) content of component / (b) content of component, 0.005 or more is preferable, 0.05 or more is more preferable, 0.1 or more is more preferable, 15 or less is preferable, and 10 or less is more Preferably it is 3 or less, more preferably 2 or less.

  The whitening agent for hydraulic composition of the present invention preferably contains a dispersant. The dispersants described above can be used, and the preferred embodiments are also the same. The content of the dispersant in the whitening agent for a hydraulic composition of the present invention is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 90% by mass or less, more preferably 70% by mass or less. Preferably, 50 mass% or less is more preferable.

  Moreover, it is preferable that the whitening agent for hydraulic compositions of this invention contains water. From the viewpoint of storage stability and from the viewpoint of improving workability, the content of water in the whitening agent for hydraulic composition is preferably 10% by mass or more, more preferably 30% by mass or more, and 50% by mass. The above is more preferable, 90% by mass or less is preferable, and 80% by mass or less is more preferable. The whitening agent for a hydraulic composition of the present invention may be in the form of a composition.

  The components used in Examples and Comparative Examples are shown below.

<(A) component>
MDEA: N-methyldiethanolamine: manufactured by Nippon Emulsifier Co., Ltd. <Comparative compound of component (a)>
TEA: Triethanolamine: manufactured by Kishida Chemical Co., Ltd.

<(B) component>
Formaldehyde: 37% by mass aqueous formaldehyde solution (formalin), manufactured by Wako Pure Chemical Industries, Ltd. (mass parts in the table are effective amounts)
Sodium hydroxymethanesulfonate: manufactured by Kanto Chemical Co., Inc.

<Cement dispersant>
Naphthalene-based dispersant: manufactured by Kao Corporation, Mighty 150
Polycarboxylic acid-based dispersant: obtained by the following Production Example 1

Production Example 1 (Production of polycarboxylic acid-based dispersant)
Into a glass reaction vessel (four-necked flask) equipped with a stirrer, 114 g of water was charged, purged with nitrogen while stirring, and heated to 80 ° C. in a nitrogen atmosphere. 60% by mass of ω-methoxypolyethylene glycol monomethacrylate (average addition mole number of ethylene oxide 120: ester purity 100%) aqueous solution 300 g, methacrylic acid (reagent: Wako Pure Chemical Industries, Ltd.) 11.5 g, and 3-mercaptopropion An aqueous solution in which 1.2 g of acid was mixed and dissolved and an aqueous solution in which 1.9 g of ammonium persulfate was dissolved in 45 g of water were dropped into the reaction vessel over 1.5 hours. Thereafter, aging was performed at 80 ° C. for 1 hour, and an aqueous solution obtained by dissolving 0.8 g of ammonium persulfate in 15 g of water was added dropwise over 30 minutes, followed by aging at 80 ° C. for 1.5 hours. After completion of aging, the mixture was cooled to 40 ° C. or lower, and then neutralized with 9.6 g of a 48% aqueous sodium hydroxide solution to obtain a copolymer (polycarboxylic acid-based dispersant) having a weight average molecular weight of 54,000 (neutralization degree: 0. 0). 7). Then, it adjusted to solid content 40 mass% using water, and obtained the 40 mass% aqueous solution of the polycarboxylic acid type dispersing agent. The molar ratio of monomer (1) / monomer (2) is 20/80. This aqueous solution was used so that the addition amount of the copolymer was the value shown in Table 2.

<Hydraulic powder>
Cement (C): Ordinary Portland cement (Ordinary Portland cement of Taiheiyo Cement Co., Ltd./Ordinary Portland cement of Sumitomo Osaka Cement Co., Ltd. = 1/1, mass ratio), density 3.16 g / cm ³
<Aggregate>
Fine aggregate (S): Jyoyo, mountain sand, FM = 2.67, density 2.56 g / cm ³
<Water>
Tap water (W)

<Preparation and evaluation of mortar>
(1) Mortar preparation process Cement (C) and fine aggregate (S) were prepared using the mortar mixer (all-purpose mixing stirrer made by Dalton Co., Ltd. model: 5DM-03-γ) under the blending conditions shown in Table 1. The mixture was added and kneaded for 10 seconds, and kneading water (W) containing a cement dispersant and an additive for hydraulic composition was added. At this time, an antifoaming agent was added so that the air entrainment amount was 2% or less. Then, mortar was prepared by main kneading for 60 seconds at a low speed rotation (63 rpm) of the mortar mixer and 120 seconds at a high speed rotation (128 rpm).

  In addition, the additive for hydraulic compositions prepared the aqueous solution which dissolved 10 mass parts of (b) component in 100 mass parts of water, (a) component or the comparison compound of (a) component, and (b) component, Was prepared by mixing the component (a) or the comparative compound of the component (a) with the aqueous solution of the component (b) in such a ratio that the amount of addition was as shown in Table 2. When only the (a) component or the comparative compound of the (a) component was added, the (a) component or the comparative compound of the (a) component was directly added to the kneaded water and used.

  Moreover, the cement dispersant and the additive for hydraulic composition of the addition amount of Table 2 were used by mixing with kneading water. Since the amount of the cement dispersant and hydraulic composition additive in the kneading water is very small, the total amount of the cement dispersant and hydraulic composition additive and the kneading water was set to the amount of W in Table 1.

(2) Mold filling step Based on JIS A 1132, mortar was filled into three cylindrical plastic molds (bottom diameter: 5 cm, height 10 cm) by a two-layer filling method.

(3) Curing and demolding step The mortar after filling is cured in the air (20 ° C) in a room at 20 ° C, and the specimen cured 24 hours after the preparation of the mortar is removed from the mold to obtain a specimen. It was.

(4) Evaluation of Hardness of Cured Body The whiteness after 24 hours of the specimen was measured under the conditions shown below using SpectroEye manufactured by x-rite. Three arbitrary chromaticities on the side surface of the specimen were measured, and an average value was obtained using the L value of the obtained Lab chromaticity as an index of whiteness.
* Whiteness measurement conditions Observation light source: D65
Observation field: 2 °
Concentration: DIN
White standard: Abs
Filter: NO

(5) Evaluation of Curing Strength The 24-hour strength of the specimen was measured based on JIS A1108, and the average value of three specimens was obtained.

In Table 2, a mass part is a mass part with respect to 100 mass parts of cement.
In Table 2, the comparative compound of component (a) is also shown in the column of component (a) for convenience, and the total of component (a) and component (b), mass ratio of component (a) / (b) Also shows the value calculated by regarding the comparative compound as component (a).

Claims (1)

  A whitening agent for a hydraulic composition, comprising N-alkyldiethanolamine having a linear alkyl group having 1 to 4 carbon atoms and formaldehyde or a formaldehyde-releasing compound.