JP5350135B2 - Dispersant for hydraulic composition - Google Patents

Description

  The present invention relates to a dispersant for a hydraulic composition and a hydraulic composition.

  Various admixtures are conventionally added to the hydraulic composition. For example, for the purpose of improving the fluidity of the hydraulic composition, naphthalene sulfonic acid formaldehyde condensate, melamine sulfonic acid formaldehyde condensate, polycarboxylic acid High molecular compounds such as salts are used. Each of these polymer compounds has unique properties and is properly used in consideration of the application of the hydraulic composition, etc., but it is also known to use a combination of these polymer compounds.

  For example, Patent Document 1 describes a slump loss prevention type cement dispersant in which an acrylic ester or methacrylic ester polymer and a cement dispersant (such as a naphthalenesulfonic acid formaldehyde condensate) are used in combination. Patent Document 2 describes a cement composition having good workability containing a polymer using hydroxyalkyl (meth) acrylate, and further describes that a polystyrenesulfonic acid-based water reducing agent can be used. ing.

  Patent Document 3 describes a concrete admixture composed of polyethylene glycol having a weight average molecular weight of 6000 to 50000 and a naphthalenesulfonic acid formaldehyde condensate for the purpose of improving high fluidity and material separation resistance. ing.

JP-A-60-161365 U.S. Pat. No. 4,792,360 JP-A-5-246744

  The dispersant used in the hydraulic composition is required to maintain good workability by appropriately suppressing a decrease in the dispersibility of the hydraulic composition over time and an increase in viscosity. Although Patent Documents 1 and 2 are said to be effective in improving workability such as fluidity, concrete having a water-cement ratio (W / C) of 50 or less is often used with increasing strength of concrete. Therefore, further improvement in suppression of dispersibility and workability is desired.

  The subject of this invention is providing the dispersing agent for hydraulic compositions which can improve the workability | operativity by suppressing the fall of the dispersibility of a hydraulic composition and a viscosity increase with time.

The present invention relates to a polymer (A) comprising a structural unit containing 70% by weight or more of a structural unit derived from a monomer represented by the following formula (1), a naphthalenesulfonic acid formaldehyde condensate (B), a polyalkylene The present invention relates to a dispersant for a hydraulic composition containing glycol (C).
H ₂ C═CHCOOCH ₂ CH ₂ OH (1)

  Moreover, this invention relates to the hydraulic composition containing the dispersing agent for hydraulic compositions of the said invention, hydraulic powder, and water.

  ADVANTAGE OF THE INVENTION According to this invention, the dispersing agent for hydraulic compositions which can suppress the fall of the dispersibility of a hydraulic composition and a viscosity increase with time, and can improve workability | operativity is provided.

  The dispersant for a hydraulic composition of the present invention is a polymer (A) [hereinafter referred to as component (A) comprising a structural unit containing 70% by weight or more of a structural unit derived from the monomer represented by the above formula (1). Naphthalenesulfonic acid formaldehyde condensate (B) [hereinafter referred to as component (B)] and polyalkylene glycol (C) [hereinafter referred to as component (C)].

<(A) component>
Component (A) is a polymer in which 70% by weight or more of the structural unit is a structural unit derived from the monomer represented by the above formula (1) [hereinafter referred to as monomer (1)]. This structural unit means the following structure.

  Component (A) is preferably 75% by weight or more, more preferably 80% by weight or more, more preferably 85% by weight or more, and still more preferably 90% by weight or more of the structural unit derived from monomer (1). By using together the component (A) in which the proportion of the structural unit derived from the monomer (1) in the structural unit is in this range together with the component (B), it is possible to effectively suppress a decrease in dispersibility over time. Can do. In addition, when there exists the salt of the acid or base neutralized in the structural unit of (A) component, the structural unit is converted with the weight of the acid type or base type before neutralization, Formula (1) The weight% of the structural unit derived from the monomer represented by is calculated.

  (A) As for the weight average molecular weight of a component, 1000-100,000 are preferable, More preferably, it is 3000-80000, More preferably, it is 5000-60000. The component (A) having a weight average molecular weight within this range is suitable for producing a one-component hydraulic composition dispersant in which the viscosity of the aqueous solution is small, the concentration of the active ingredient is high, and it is easy to handle. The weight average molecular weight of the component (A) is measured by using size exclusion chromatography (GPC) and using polystyrene as a RI detector and a calibration substance. The measurement conditions are as described in Comparative Synthesis Example 1 described later.

  The component (A) can be obtained by a known polymerization method, and the polymerization concentration is preferably 10% by weight or more from an industrial viewpoint. The polymerization method can be performed by a method such as radical polymerization, living radical polymerization, or ionic polymerization, and is preferably a radical polymerization method. The polymerization solvent is not limited as long as the monomer is soluble, but includes water, methyl alcohol, ethyl alcohol, isopropyl alcohol, benzene, toluene, xylene, cyclohexane, n-hexane, ethyl acetate, acetone, methyl ethyl ketone, and the like. Water, methyl alcohol, ethyl alcohol and isopropyl alcohol are preferred.

  As the polymerization initiator, known initiators such as an azo initiator, a peroxide initiator, a macro initiator, and a redox initiator may be used. In the case of a polymerization solvent containing water, as a polymerization initiator, an ammonium salt or alkali metal salt of persulfuric acid, hydrogen peroxide, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis ( Water-soluble azo compounds such as 2-methylpropionamido) dihydrate. In the case of a polymerization solvent not containing water, examples of the polymerization initiator include peroxides such as benzoyl peroxide and lauroyl peroxide, and aliphatic azo compounds such as azobisisobutyronitrile.

  Furthermore, you may use a chain transfer agent for the purpose of molecular weight adjustment as needed. Examples of chain transfer agents include thiol chain transfer agents and halogenated hydrocarbon chain transfer agents, and thiol chain transfer agents are preferred.

As the thiol chain transfer agent, those having a —SH group are preferable, and in particular, the general formula HS—R—Eg (wherein R represents a hydrocarbon-derived group having 1 to 4 carbon atoms, and E is − OH, —COOM, —COOR ′ or —SO ₃ M group, M represents a hydrogen atom, monovalent metal, divalent metal, ammonium group or organic amine group, and R ′ represents an alkyl having 1 to 10 carbon atoms. In which g represents an integer of 1 to 2, for example, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, Examples include octyl thioglycolate, octyl 3-mercaptopropionate, and the like from the viewpoint of chain transfer effect in a copolymerization reaction including monomers 1 to 3. Mercaptoethanol are preferable, more preferably mercaptopropionic acid. These 1 type (s) or 2 or more types can be used.

  Examples of the halogenated hydrocarbon chain transfer agent include carbon tetrachloride and carbon tetrabromide.

  Examples of other chain transfer agents include α-methylstyrene dimer, terpinolene, α-terpinene, γ-terpinene, dipentene, 2-aminopropan-1-ol and the like. A chain transfer agent can use 1 type (s) or 2 or more types.

  The polymerization temperature is not particularly limited but is preferably controlled in a region up to the boiling point of the polymerization solvent.

  As the component (A), a monomer other than the monomer (1) can be used as a constituent monomer. For example, (i) monocarboxylic acids such as (meth) acrylic acid and crotonic acid or salts thereof (for example, alkali metal salts, alkaline earth metal salts, ammonium salts, mono-, di-, tri-alkyls in which hydroxyl groups may be substituted) Alkyl (C2-C8) ammonium salt) or esters thereof (for example, acrylic acid esters or methacrylic acid esters other than the monomer (1)). Further, for example, (ii) a dicarboxylic acid monomer such as maleic acid, itaconic acid, fumaric acid or the like, or an anhydride or salt thereof (for example, alkali metal salt, alkaline earth metal salt, ammonium salt, hydroxyl group is substituted) Mono, di, trialkyl (carbon number 2 to 8) ammonium salt) or ester may be mentioned. Among these, (meth) acrylic acid, maleic acid, and maleic anhydride are preferable, and (meth) acrylic acid or alkali metal salts thereof are more preferable. In addition, (meth) acrylic acid means acrylic acid and / or methacrylic acid (hereinafter the same).

  The component (A) can be used as an aqueous solution or a solid powder. The solid content concentration can be selected and used at 1 to 100% by weight. However, from the viewpoint of preparing the dispersant of the present invention by mixing the component (A) with the component (B), the solid content concentration is 20%. -100 wt% is preferable, and 30-100 wt% is preferable. Moreover, from a viewpoint which synthesize | combines (A) component and obtains as aqueous solution, 10 to 70 weight% is preferable, 15 to 60 weight% is more preferable, and 20 to 50 weight% is more preferable.

<(B) component>
The component (B) is a naphthalenesulfonic acid formaldehyde condensate, and the weight average molecular weight is preferably 200000 or less, more preferably 100000 or less, further preferably 80000 or less, and more preferably 50000 or less. Further, the weight average molecular weight is preferably 1000 or more, more preferably 3000 or more, further preferably 4000 or more, and more preferably 5000 or more. Therefore, 1000-200000 are preferable, 3000-100000 are more preferable, 4000-80000 are still more preferable, 5000-50000 are still more preferable. The (B) component naphthalenesulfonic acid formaldehyde condensate may be in an acid state or a neutralized product.

  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 to 1.4 mol of sulfuric acid is used with respect to 1 mol of naphthalene and reacted at 150 to 165 ° C. for 2 to 5 hours to obtain a sulfonated product. Next, formalin is added dropwise at 85 to 95 ° C. over 3 to 6 hours to form 0.95 to 0.99 mol as formaldehyde with respect to 1 mol of the sulfonated product, and condensed at 95 to 105 ° C. after the addition. Perform the reaction. If necessary, water and a neutralizing agent are added to the condensate, and a neutralization step is performed at 80 to 95 ° C. The neutralizing agent is preferably added in an amount of 1.0 to 1.1 moles per each of naphthalenesulfonic acid and unreacted sulfuric acid. 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 it is or as a component (B) by appropriately adding other components. Although the solid content concentration of the aqueous solution depends on the use, the component (B) is preferably 0.3 to 50% by weight from the viewpoint of the dispersion performance of the hydraulic powder and the handleability due to the viscosity of an appropriate aqueous solution, 5 to 45% by weight is more preferable, and 30 to 45% by weight is still more preferable. Further, if necessary, the aqueous solution can be dried and powdered to obtain a powdery naphthalenesulfonic acid formaldehyde condensate water-soluble salt, which may be used as the powdery component (B). Drying and powdering can be performed by spray drying, drum drying, freeze drying, or the like.

<(C) component>
Component (C) is polyalkylene glycol, and examples thereof include polyethylene glycol and polypropylene glycol, and polyethylene glycol is preferable from the viewpoint of mixing with hydraulic powder and water. The number average molecular weight of the component (C) is preferably 5000 to 50000, more preferably 10000 to 40000, more preferably 15000, from the viewpoint of suppressing the decrease in dispersibility of the hydraulic composition and suppressing the increase in viscosity of the hydraulic composition. 40,000 is more preferable. The number average molecular weight is 5000 or more and tends to be excellent in suppressing the decrease in dispersibility. The number average molecular weight is 50000 or less, and the hydraulic composition tends to have low viscosity and excellent workability. As alkylene glycol, C2-C6 alkylene glycol is mentioned, Ethylene glycol and propylene glycol are preferable and ethylene glycol is more preferable. Further, the component (C) may be a copolymer of a plurality of alkylene glycols or an alkylene glycol having a terminal modified, but it is preferable that the terminal is not modified. Examples of the copolymer of a plurality of alkylene glycols include a polymer composed of ethylene glycol and propylene glycol, and a polymer composed of ethylene glycol, propylene glycol and butylene glycol. Examples of the alkylene glycol having a terminal modified include linear or branched alkoxy polyalkylene glycols having 1 to 8 carbon atoms such as alkoxy polyethylene glycol.

<Dispersant for hydraulic composition>
In the dispersant for a hydraulic composition of the present invention, the weight ratio (A) / (B) of the component (A) to the component (B) is preferably 1/99 to 75/25. From the viewpoint of the mixing property of the component (A) and the component (B) and the dispersibility of the hydraulic composition, it is more preferably 1/99 to 50/50, and further preferably 1/99 to 45/55. Preferably, it is still more preferable that it is 1 / 99-30 / 70. Further, from the viewpoint of suppressing the decrease in dispersibility over time of the hydraulic composition, that is, from the viewpoint of retention, it is more preferably 5/95 to 40/60, and even more preferably 5/95 to 30/70. The weight ratio in this range is preferable from the viewpoints of dispersibility and dispersion retention, and from the viewpoint of obtaining a one-part preparation having a uniform and stable handling property as an aqueous solution. (B) component contributes to the initial dispersibility as a reason for excellent dispersibility and retention, and then (A) component has a synergistic effect with component (B) even if component (A) is an amount that is less effective with component (A) alone Therefore, it is presumed that it exhibits dispersibility and is excellent in retention.

  The (A) / (B) weight ratio is preferably 1/99 to 45/55 when the structural unit derived from the monomer represented by the formula (1) in the component (A) is 80% by weight or more. In the case of 85% by weight or more, preferably 1/99 to 50/50, and in the case of 90% by weight or more, preferably 1/99 to 75/25.

  In the dispersant for hydraulic composition of the present invention, the weight ratio of the component (A) to the component (C) is 60 in terms of (A) / (C) from the viewpoint of suppressing the decrease in dispersibility of the hydraulic composition. / 40 to 98/2 is preferable, and 70/30 to 95/5 is more preferable. Moreover, it is preferable that the weight ratio of (B) component and (C) component is 99 / 1-70 / 30 by (B) / (C), and it is more preferable that it is 99 / 1-80 / 20. (A) component, (B) component, and (C) component are 2-50 weight part of (A) component with respect to 100 weight part of these total from a viewpoint of suppression of a dispersible fall, (B) The component is preferably 40 to 97.8 parts by weight, the component (C) is preferably 0.2 to 15 parts by weight, the component (A) is 4.5 to 25 parts by weight, the component (B) is 70 to 95 parts by weight, The component (C) is more preferably 0.5 to 5 parts by weight.

  The dispersant for a hydraulic composition of the present invention can be used in the form of a solid such as powder or granules, or in the form of a liquid or paste by dissolving or dispersing in a solvent. Especially, the liquid form which is a uniform solution is preferable. In the case of the liquid form, a solution containing the component (A), the component (B) and the component (C), and further an aqueous solution are preferable. When used as an aqueous solution, the content of the component (A) in the aqueous solution is preferably 0.1 to 50% by weight, more preferably 3 to 20% by weight, and the content of the component (B) is preferably 0.3 to 50% by weight, more preferably 5 to 45% by weight, and the content of component (C) can be preferably 0.02 to 15% by weight, more preferably 1 to 5% by weight. In the case of the aqueous solution, the water content is preferably 30 to 80% by weight, more preferably 40 to 70% by weight. Moreover, 20-70 weight% is preferable and, as for the total amount of (A) component, (B) component, and (C) component, 30-60 weight% is more preferable. When used in a liquid state, an organic solvent other than water can be used as the solvent.

  The dispersant for a hydraulic composition of the present invention includes a dispersant other than the component (A), the component (B), and the component (C), an air entraining agent (AE agent), an antifoaming agent, and a fluidizing agent. It is also possible to use drugs such as thickeners, early strengthening agents, and retarding agents in combination.

<Hydraulic composition>
The hydraulic composition of the present invention contains the dispersant for a hydraulic composition of the present invention, a hydraulic powder, and water.

  The hydraulic powder used in the hydraulic composition of the present invention is a powder having physical properties that are cured by a hydration reaction, and examples thereof include cement and gypsum. Preferred are ordinary Portland cement, Belite cement, moderate heat cement, early strong cement, super early strong cement, sulfuric acid resistant cement, etc., and blast furnace slag, fly ash, silica fume, stone powder (calcium carbonate powder), etc. May be added. The hydraulic composition of the present invention can also contain aggregates and the like. In addition, the hydraulic composition finally obtained by adding sand, sand and gravel as aggregates to these powders is generally called mortar, concrete, etc., respectively. The hydraulic composition of the present invention is used in the field of ready-mixed concrete, concrete vibration products, self-leveling, refractory, plaster, gypsum slurry, lightweight or heavy concrete, AE, repair, pre-packed, tray It is useful in any field of various concrete such as for grouting, for ground improvement, for cold weather.

  The hydraulic composition of the present invention has a water / hydraulic powder ratio [weight percentage (% by weight) of water and hydraulic powder in the slurry, usually abbreviated as W / P. , W / C may be abbreviated. ] Can be 5 to 500% by weight, further 10 to 200% by weight, and further 10 to 100% by weight.

  In the hydraulic composition, the dispersant for the hydraulic composition of the present invention is 0.001 to 10 in total of the component (A), the component (B), and the component (C) with respect to 100 parts by weight of the hydraulic powder. It is preferably added in a ratio (in terms of solid content) of parts by weight, further 0.01 to 5 parts by weight, and further 0.05 to 1 part by weight. Further, the component (A) is added in a ratio (in terms of solid content) of 0.0005 to 4.5 parts by weight and further 0.005 to 2.25 parts by weight with respect to 100 parts by weight of the hydraulic powder. Is preferred. In addition, the component (B) is added in a ratio (in terms of solid content) of 0.0055 to 9.5 parts by weight and further 0.0055 to 4.75 parts by weight with respect to 100 parts by weight of the hydraulic powder. Is preferred. The component (C) is preferably added at a ratio (in terms of solid content) of 0.0001 to 1.2 parts by weight, and further 0.0001 to 0.55 parts by weight with respect to 100 parts by weight of the hydraulic powder. .

  By adding the component (A), the component (B), and the component (C) according to the present invention to a composition containing a hydraulic powder and water, the hydraulic powder in the composition Dispersibility can be improved, and a decrease in dispersibility and an increase in viscosity can be suppressed. Therefore, it is possible to obtain a hydraulic composition excellent in workability with little deterioration in dispersibility over time. Component (A), component (B) and component (C) may be added to a composition containing hydraulic powder and water after mixing the three components in advance, and component (A) And (B) component may be prepared and added to a composition containing hydraulic powder and water together with (C) component, or (A) component, (B) component and (C) component Each of these may be added separately to a composition containing hydraulic powder and water. Moreover, it is also preferable to adjust the mixture of (A) component and (C) component from a viewpoint of the mixing property of each component, and to add to the composition containing hydraulic powder and water with (B) component. From the viewpoint of ease of addition, it is preferable to add the mixture containing the component (A), the component (B), and the component (C) to the composition containing hydraulic powder and water. In the case where the component (A), the component (B), and the component (C) are added separately, from the viewpoint of suppressing dispersibility of the hydraulic composition and deterioration of dispersibility over time, the component (A) and ( It is preferable to satisfy the weight ratio of the component B) and the component (C).

[Component (A)]
As the component (A) and the comparative polymer, the following comparative synthetic examples and synthetic polymers were used.

<Synthetic raw material>
Hydroxyethyl acrylate: Aldrich (96% effective content) [monomer (1)]
Acrylic acid: Aldrich (99% effective)
-Methyl acrylate: Wako Pure Chemical Industries, Ltd. (effective portion 98%)
-Ethyl acrylate: Wako Pure Chemical Industries, Ltd. (97% effective)
・ Sodium methallylsulfonate: Wako Pure Chemical Industries, Ltd. (effective portion 98%)
・ Mercaptopropionic acid: Aldrich
・ Ammonium peroxodisulfate: Wako Pure Chemical Industries, Ltd.
V-65: 2,2′-azobis (2,4-dimethylvaleronitrile), Wako Pure Chemical Industries, Ltd.

<Synthesis example>
Comparative Synthesis Example 1
82.5 g of ion exchange water was put into a four-necked flask of the reaction vessel, and after deaeration, the atmosphere was changed to nitrogen. Acrylic acid (hereinafter referred to as AA) 33.4 g and hydroxyethyl acrylate (hereinafter referred to as HEA) 69.7 g were mixed to prepare a monomer solution. An aqueous initiator solution (1) was prepared by dissolving 1.42 g of ammonium peroxodisulfate in 28.3 g of ion-exchanged water. An aqueous chain transfer agent solution was prepared by dissolving 2.2 g of 3-mercaptopropionic acid in 25 g of ion-exchanged water. The reaction vessel was brought to 80 ° C., and the monomer solution, the initiator aqueous solution (1) and the chain transfer agent aqueous solution were simultaneously added dropwise over 90 minutes. Thereafter, 0.4 g of ammonium peroxodisulfate was dissolved in 7.1 g of ion-exchanged water to prepare an initiator aqueous solution (2), which was added dropwise over 30 minutes, and further reacted at 80 ° C. for 60 minutes. After completion of the reaction, the reaction solution was brought to room temperature and neutralized with a 48% aqueous sodium hydroxide solution to obtain an aqueous solution of polymer a-1 having a solid content of 41% by weight and a pH of 5.
Preparation composition ratio:
AA / HEA = 32.4 / 67.6 (weight ratio) (HEA 67.6% by weight)
AA / HEA = 43.6 / 56.4 (molar ratio)
Weight average molecular weight: 45300
AA: reaction rate 98% (HPLC)
HEA: 99% reaction rate (HPLC)
The molecular weight was measured under the following GPC conditions.
[GPC conditions]
Standard material: Polystyrene conversion column: G4000PWXL + G2500PWXL (Tosoh)
Eluent: 0.2M phosphate buffer / acetonitrile = 9/1
Flow rate: 1.0 mL / min Column temperature: 40 ° C
Detector: RI

Comparative Synthesis Example 2
158.5 g of isopropyl alcohol (hereinafter referred to as IPA) was placed in a four-necked flask of the reaction vessel. A monomer liquid consisting of 66.7 g of methyl acrylate was prepared. An initiator solution (1) in which 1.2 g of V-65 and 38.1 g of IPA were mixed was prepared. A chain transfer agent solution in which 0.8 g of 3-mercaptopropionic acid was mixed with 25 g of IPA was prepared. The reaction vessel was brought to 70 ° C., and the monomer solution, initiator solution (1) and chain transfer agent solution were simultaneously added dropwise over 60 minutes. Thereafter, 0.3 g of V-65 was mixed with 15 g of IPA to prepare an initiator solution (2), which was added dropwise over 30 minutes, and further reacted at 70 ° C. for 30 minutes. After completion of the reaction, the polymer was precipitated and became cloudy at room temperature, but acetone was added to make it uniform, and the solvent was removed to obtain a polymer a-2.
Charge composition ratio: methyl acrylate 100 mol%
Weight average molecular weight: 4100
Methyl acrylate: 94% reaction rate (H-NMR)
The molecular weight was measured under the following GPC conditions.
[GPC conditions]
Standard material: Polystyrene conversion column: K804L + K804L
Eluent: 1 mmol / L Farmin DM20 (Kao Corporation: Dimethyllaurylamine) / Methyl chloride flow rate: 1.0 ml / min Column temperature: 40 ° C
Detector: RI

Synthesis example 1
Into a four-necked flask of the reaction vessel, 84.2 g of ion-exchanged water was charged, and after deaeration, a nitrogen atmosphere was established. A monomer solution was prepared by mixing 20.2 g of AA and 83.5 g of HEA. An initiator aqueous solution (1) was prepared by dissolving 1.3 g of ammonium peroxodisulfate in 26.4 g of ion-exchanged water. 2.6 g of 3-mercaptopropionic acid was dissolved in 25 g of ion-exchanged water to prepare an aqueous chain transfer agent solution. The reaction vessel was brought to 80 ° C., and the monomer solution, the initiator aqueous solution (1) and the chain transfer agent aqueous solution were simultaneously added dropwise over 90 minutes. Thereafter, an aqueous initiator solution (2) obtained by dissolving 0.3 g of ammonium peroxodisulfate in 6.6 g of ion-exchanged water was added dropwise over 30 minutes, and further reacted at 80 ° C. for 60 minutes. After completion of the reaction, the reaction solution was brought to room temperature and neutralized with a 48% aqueous sodium hydroxide solution to obtain an aqueous solution of polymer A-1 having a solid content of 43% by weight and a pH of 5.
Preparation composition ratio:
AA / HEA = 19.5 / 80.5 (weight ratio) (HEA 80.5 wt%)
AA / HEA = 28.0 / 72.0 (molar ratio)
Weight average molecular weight: 34500
AA: 97% reaction rate (HPLC)
HEA: 98% reaction rate (HPLC)
The measurement conditions for GPC are the same as in Comparative Synthesis Example 1.

Synthesis example 2
The reaction vessel was charged with 224.5 g of ion-exchanged water in a four-necked flask, and after deaeration, the atmosphere was set to nitrogen. An initiator aqueous solution (1) was prepared by dissolving 4.4 g of ammonium peroxodisulfate in 90 g of ion-exchanged water. A chain transfer agent aqueous solution in which 10.2 g of 3-mercaptopropionic acid was dissolved in 80 g of ion-exchanged water was prepared. The monomer vessel of HEA 280 g, the initiator aqueous solution (1) and the chain transfer agent aqueous solution were dropped simultaneously over 90 minutes at 80 ° C. Thereafter, an initiator aqueous solution (2) obtained by dissolving 0.6 g of ammonium peroxodisulfate in 10 g of ion-exchanged water was dropped over 30 minutes, and further reacted at 80 ° C. for 60 minutes. After completion of the reaction, the mixture was brought to room temperature and neutralized while stirring with a 48% aqueous sodium hydroxide solution. An aqueous solution of polymer A-2 having a solid content concentration of 41% by weight and a pH of 5 was obtained.
Charge composition ratio: HEA 100 mol% (100 wt%)
Weight average molecular weight: 14200
HEA: 96% reaction rate (HPLC)
The measurement conditions for GPC are the same as in Comparative Synthesis Example 1.

[(B) component]
As the component (B), naphthalenesulfonic acid formaldehyde condensate (B-1) obtained in Synthesis Example B-1 below was used.
<Synthesis Example B-1>
44 g of water was added to a product (sulfonated product) obtained by reacting 1 mol (128.2 g) of naphthalene and 1.28 mol (125.5 g) of sulfuric acid at 150 ° C. to 160 ° C. for 3 hours. 37% aqueous solution of formaldehyde) was added dropwise at 90 ° C. over 3 hours in an amount of 0.98 mol as formaldehyde. After dropping, a condensation reaction was performed at 100 ± 2 ° C. for 10 hours. After completion of the reaction, the mixture was brought to room temperature, neutralized with calcium hydroxide to pH 5, and the resulting precipitate (gypsum) was removed by filtration to obtain an aqueous solution of naphthalenesulfonic acid formaldehyde condensate (B-1). The polymer was dried at 105 ° C. for 24 hours, and the aqueous solution concentration was adjusted as necessary.
Weight average molecular weight: 13000
The molecular weight was measured under the following GPC conditions.
[GPC measurement conditions]
Column: G4000SW _XL + G2000SW _XL
Eluent: 30 mM sodium acetate / acetonitrile = 6/4 vol%
Flow rate: 0.7ml / min Detector: UV 280nm
Column temperature: 25 ° C
<Column pretreatment>
Coating solution: 30 mM sodium acetate / acetonitrile = 6/4 vol% containing 0.5% naphthalenesulfonic acid dispersant (Mao 100, manufactured by Kao Corporation)
Flow rate: 0.2 ml / min Time: 72 hours

[Component (C)]
C-1: Polyethylene glycol (number average molecular weight 35000)

<Example 1> [Mortar flow]
Cement (Pacific Ocean Cement / Sumitomo Osaka Cement manufactured = 1: 1 (by weight); density = 3.16 g / cm ³⁾ 400 g and mountain sand (Joyo production, density = 2.55 g / cm ³⁾ 700 g of the universal mixing stirrer (Model number: 5DM-03-r, manufactured by Dalton Co.), set to low speed and stirred for 10 seconds. Thereafter, 160 g of a previously prepared aqueous dispersant solution was added (starting water contact), and stirring was performed for 90 seconds at a low speed. After stirring, the mortar was filled into a cone (lower diameter 100 mm, upper diameter 70 mm, height 60 mm), and the mortar flow was measured based on JIS R 5201 (immediately after). In addition, the drop motion described in JIS R 5201 is not performed. The flow value is an average value of the length in the direction recognized as the maximum and the length in the direction perpendicular thereto. Moreover, the mortar flow after 30 minutes and 60 minutes after the start of water contact was also measured. In this example, evaluation of dispersibility over time was performed. In addition, 160 g of the dispersing agent aqueous solution includes a dispersing agent using each component in an amount such that the solid content added to 100 parts by weight of cement is parts by weight shown in Table 1, 0.05 g of an antifoaming agent, and the remaining water. It consists of The results are shown in Table 1. Further, the mortar viscosity of the products 1-1 and 1-2 of the present invention was not much different from the comparative products 1-3 and 1-4, and had the same workability. In Comparative Examples 1-5 and 1-6 in Table 1, components not corresponding to the component (A) are described in the column of the component (A) for convenience.

  For solids, put about 3g of sample solution into an aluminum foil cup, measure the weight, dry at 105 ° C for 2 hours, measure the weight again, and calculate the solids concentration in the solution from the change in weight. did. It is preferable that the mortar flow has little decrease from the value immediately after 30 minutes, preferably until 60 minutes.

Claims (4)

A polymer composed of a structural unit containing 70% by weight or more of a structural unit derived from a monomer represented by the following formula (1), which is other than the structural unit derived from a monomer represented by the following formula (1) When the structural unit is included, the structural unit is a polymer (A) that is a structural unit derived from acrylic acid or an alkali metal salt thereof , naphthalenesulfonic acid formaldehyde condensate (B), and polyalkylene glycol (C). contain,
The weight ratio of the polymer (A) and the naphthalenesulfonic acid formaldehyde condensate (B) is (A) / (B), and is 1/99 to 45/55,
The weight ratio of the polymer (A) to the polyalkylene glycol (C) is 60/40 to 95/5 in (A) / (C).
Dispersant for hydraulic composition.
H ₂ C═CHCOOCH ₂ CH ₂ OH (1) Hydraulic composition dispersant according to claim 1 having a number average molecular weight of 5,000 to 50,000 of the polyalkylene glycol (C). The dispersant for a hydraulic composition according to claim 1 or 2 , wherein the polymer (A) has a weight average molecular weight of 1,000 to 100,000. The hydraulic composition containing the dispersing agent for hydraulic compositions in any one of Claims 1-3 , hydraulic powder, and water.