JP2022007923A - Method of producing powder dispersant composition for hydraulic composition - Google Patents

Abstract

To provide a method of producing a powder dispersant composition for hydraulic composition, the method capable of producing a polycarboxylic acid-based dispersant in a powder state at a high yield.SOLUTION: The method of producing a powder dispersant composition for hydraulic composition is a method of producing powders containing copolymer obtained by dehydrating a mixture of the copolymer and water, the copolymer having a constituent unit (1) expressed by a specified formula and a constituent unit (2) expressed by a specified formula. In a case where n of the constituent unit (2) of the copolymer is smaller than 40, the dehydration is performed by the thin film drying method or the spray drying method after adjusting pH of the mixture to 11 or higher and 14 or lower; in a case where n of the constituent unit (2) of the copolymer is 40 or larger and smaller than 80, the dehydration is performed by the thin-film dry method or the spray dry method after adjusting pH of the mixture to 9 or higher and 14 or lower; and in a case where n of the constituent unit (2) of the copolymer is 80 or larger, the dehydration is performed by the thin-film dry method or the spray dry method after adjusting pH of the mixture to 7 or higher and 14 or lower.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a powder dispersant composition for a hydraulic composition.

In recent years, the aging of major infrastructure built during the period of high economic growth has become apparent in Japan, and the era of major infrastructure renewal and renovation is approaching. Among them, the field where demand is expected to grow is the repair / reinforcement field, and in this field, the use of repair materials in which a hydraulic composition and a powdery dispersant (hereinafter referred to as powder dispersant) are premixed is used. It is mainstream.

Examples of the powder dispersant premixed in the repair material include a naphthalene sulfonic acid-based dispersant, a polycarboxylic acid-based dispersant, and a melamine sulfonic acid-based dispersant. It is highly evaluated that the amount of addition can be reduced and that it has good compatibility with a polymer-based thickener typified by methyl cellulose.

Examples of the powder dispersant powdering method include a drum drying method, a disk drying method, a thin film drying method typified by a belt drying method, a spray drying method, a kneader method, and an inorganic powder supporting method. Of particular importance in the powdering process are the melting point and vitrification temperature of the dispersant, which is a polycarboxylic acid-based dispersant consisting of an adsorbent group having the same polymerization ratio and an ethyleneoxy group (hereinafter, also referred to as EO) graft chain. Compared with, the polycarboxylic acid-based powder dispersant having a larger average number of moles of EO added to the EO graft chain, which is a steric repulsive group, has a higher freezing point, so that it has excellent thin film formability and pulverizability during cooling, and is relatively powdery. It's easy.

Patent Document 1 describes the production of a powdered cement dispersant containing a acrylate-based or methacrylate-based polymer compound having a predetermined structural unit as a main component, adding a reducing agent to a mixture containing water or a solvent, and then drying. The method is disclosed. Patent Document 2 discloses a powder dispersant for an amorphous refractory containing a polymer compound having a polyalkylene glycol chain and a reducing compound.

Japanese Unexamined Patent Publication No. 2000-169206 Japanese Unexamined Patent Publication No. 2001-213761

However, in the general step of powdering a polycarboxylic acid-based dispersant, a commercially acceptable yield is obtained by a drying method in which water is evaporated to obtain a powder as the average number of moles of EO added to the EO graft chain decreases. It may be difficult to obtain a powder dispersant at a rate (for example, 90% or more as the mass at the time of drying with respect to the mass of the solid content of the dispersant before drying).

The present invention provides a method for producing a powder dispersant composition for a water-hard composition, which can produce a powdered polycarboxylic acid-based dispersant in a high yield.

In the present invention, a copolymer having a structural unit (1) represented by the following formula (1) and a structural unit (2) represented by the following formula (2), and a mixture containing water are dried and the same. A method for producing a powder dispersant composition for a water-hard composition, which comprises producing a powder containing a polymer.
When the copolymer is a copolymer in which n of the structural unit (2) is less than 40, the mixture is dried by a thin film drying method or a spray drying method with a pH of 11 or more and 14 or less.
When the copolymer is a copolymer in which n of the structural unit (2) is 40 or more and less than 80, the mixture is dried by a thin film drying method or a spray drying method with a pH of 9 or more and 14 or less.
When the copolymer is a copolymer in which n of the structural unit (2) is 80 or more, the mixture is dried by a thin film drying method or a spray drying method with a pH of 7 or more and 14 or less.
The present invention relates to a method for producing a powder dispersant composition for a hydraulic composition.

(In the formula, R ¹ and R ³ indicate the same or different hydrogen atom or methyl group, respectively, and R ² and R ⁴ are the same or different, each of which is a hydrogen atom or an alkyl group having 1 or more and 3 or less carbon atoms. , M indicates a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium or an organic ammonium, p indicates a number of 0 or more and 2 or less, q indicates a number of 0 or 1, and n indicates an average number of added moles. Indicates a number of 5 or more and 150 or less.)

Further, in the present invention, the copolymer having the structural unit (1) represented by the formula (1) and the structural unit (2) represented by the formula (2) and the mixture containing water are dried. A method for producing a powder dispersant composition for a water-hard composition, which comprises producing a powder containing the copolymer.
When the copolymer is a copolymer in which n of the structural unit (2) is less than 40, the mixture is dried with a pH of 11 or more and 14 or less.
When the copolymer is a copolymer in which n of the structural unit (2) is 40 or more and less than 80, the mixture is dried with a pH of 9 or more and 14 or less.
When the copolymer is a copolymer in which n of the structural unit (2) is 80 or more and less than 100, the mixture is dried with a pH of 8 or more and 14 or less.
When the copolymer is a copolymer in which n of the structural unit (2) is 100 or more, the mixture is dried with a pH of 7 or more and 14 or less.
The present invention relates to a method for producing a powder dispersant composition for a hydraulic composition.

Hereinafter, the method for producing a powder dispersant composition for a hydraulic composition of the present invention includes these two production methods. The matters described below can be appropriately applied to each manufacturing method.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a method for producing a powder dispersant composition for a water-hard composition, which can produce a powdered polycarboxylic acid-based dispersant in a high yield.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a method for producing a powder dispersant composition for a water-hard composition, which solves a problem in the production of a powdered polycarboxylic acid-based dispersant in a drying method. That is, the yield of the powder dispersant can be increased by adjusting the pH of the mixture containing the polycarboxylic acid-based dispersant, for example, the aqueous solution, to a predetermined value according to the number of moles of EO added to the copolymer. , A method for producing a powder dispersant composition for a water-hardening composition is provided.

The mechanism by which the copolymer can be powdered and the yield is improved by the method for producing a powder dispersant composition for a water-hardening composition of the present invention is presumed as follows. Since the polycarboxylic acid-based dispersant contains a monomer having a carboxy group as a polymerization unit, it is considered that the degree of dissociation of the carboxy group increases as the pH is improved. This means that the polymerization unit is more strongly negatively charged, and it is expected that the spread of the polymer chain will be increased by the electrostatic repulsive force. As a result, it is considered that the drying property is improved by increasing the polymer molecular volume and the drying area. In the present invention, it is presumed that the above-mentioned dryness is further improved by setting an appropriate pH according to the average number of moles of EO added to the EO graft chain.

<Copolymer 1>
The copolymer 1 is a copolymer having a structural unit (1) represented by the formula (1) and a structural unit (2) represented by the formula (2).

Regarding the structural unit (1) represented by the formula (1), from the viewpoint of reactivity and easiness of powdering, R ¹ is a hydrogen atom or a methyl group, and preferably contains a methyl group. M is a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium or an organic ammonium, and is preferably an alkali metal or an alkaline earth metal from the viewpoint of ease of powdering. The structural unit (1) may be two or more types. Examples of the monomer serving as the structural unit (1) include acrylic acid, methacrylic acid, and a monomer selected from salts thereof.

Regarding the structural unit (2) represented by the above formula (2), R ² and R ⁴ are the same or different from each other from the viewpoint of reactivity and easiness of powdering, and have hydrogen atoms or carbon atoms of 1 or more and 3 respectively. These are the following alkyl groups, each of which is preferably an alkyl group having 1 carbon atom, that is, a methyl group. Further, R ³ is a hydrogen atom or a methyl group from the viewpoint of easiness of powdering, and a hydrogen atom is preferable. The structural unit (2) may be two or more types. p represents a number of 0 or more and 2 or less, and is preferably 0 or more and 1 or less, and more preferably 0, from the viewpoint of easiness of powdering. From the viewpoint of easiness of powdering, q represents a number of 0 or 1, and is preferably 1. n is the average number of moles added, and represents a number of 5 or more and 150 or less from the viewpoint of easiness of powdering. n is preferably 20 or more, more preferably 40 or more, still more preferably 60 or more. And n is preferably 140 or less, more preferably 130 or less, still more preferably 120 or less. Examples of the monomer serving as the structural unit (2) include a monomer selected from methoxypolyethylene glycol monomethacrylate, polyoxyethylene metharyl ether, polyoxyethylene isoprenyl ether, and polyoxyethylene vinyl ether.

The molar ratio of the structural unit (1) and the structural unit (2) in the copolymer 1 is the structural unit (1) / the structural unit (2), preferably 1 or more, more preferably, from the viewpoint of easiness of powdering. 2 or more, more preferably 3 or more, still more preferably 5 or more, still more preferably 8 or more, and preferably 10 or less, more preferably 9 or less, still more preferably 7 or less, still more preferably 5 or less. It is even more preferably 4 or less, and even more preferably 3 or less.

The weight average molecular weight of the copolymer 1 is preferably 20,000 or more, more preferably 25,000 or more, still more preferably 30,000 or more, still more preferably 40,000 or more, from the viewpoint of ease of powdering. And, preferably 70,000 or less, more preferably 60,000 or less, still more preferably 50,000 or less, still more preferably 45,000 or less. This weight average molecular weight was measured by gel permeation chromatography (GPC) under the following conditions.
* GPC conditions Equipment: GPC (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: 1.0 mL / min
Column temperature: 40 ° C
Detection: RI
Sample size: 0.2 mg / mL
Standard substance: Polyethylene glycol equivalent (monodisperse polyethylene glycol: molecular weight 87,500, 250,000, 145,000, 46,000, 24,000)

The copolymer 1 may have a structural unit (hereinafter referred to as a structural unit (3)] other than the structural unit (1) and the structural unit (2). Examples of the arbitrary monomer serving as the structural unit (3) include ethylene glycol methacrylate phosphate, methyl acrylate, and 2-hydroxyethyl acrylate.

From the viewpoint of ease of powdering, the ratio of the total of the structural units (1) and the structural units (2) to the total structural units of the copolymer 1 is preferably 80 mol% or more, more preferably 90 mol% or more. It is more preferably 95 mol% or more, and preferably 100 mol% or less, and may be 100 mol%.

From the viewpoint of ease of powdering, the ratio of the total of the structural units (1) and the structural units (2) to the total structural units of the copolymer 1 is preferably 80% by mass or more, more preferably 90% by mass or more. , And preferably 100% by mass or less, and may be 100% by mass.

From the viewpoint of ease of powdering, the proportion of metharylsulfonic acid or a salt thereof in all the constituent units of the copolymer 1 is preferably 1 mol% or less, more preferably 0.5 mol% or less, still more preferably. Is 0.1 mol% or less, more preferably 0.05 mol% or less, even more preferably 0.01 mol% or less, still more preferably substantially free, that is, even more preferably substantially 0 mol. %, More preferably 0 mol%.
Further, the proportion of polyamide polyamine in all the constituent units of the copolymer 1 is preferably 1% mol or less, more preferably 0.5 mol% or less, still more preferably, from the viewpoint of ease of powdering. 0.1 mol% or less, still more preferably 0.05 mol% or less, even more preferably 0.01 mol% or less, even more preferably substantially free, that is, even more preferably substantially 0 mol%. , More preferably 0 mol%.

In the present invention, a mixture containing the copolymer 1 and water (hereinafter, also referred to as a drying mixture) is dried under predetermined conditions to produce a powder containing the copolymer 1. The drying mixture is preferably an aqueous solution.
In the present invention
When the copolymer 1 is a copolymer in which n of the structural unit (2) is less than 40, the pH of the drying mixture is set to 11 or more and 14 or less, and the mixture is dried by a thin film drying method or a spray drying method.
When the copolymer 1 is a copolymer in which n of the structural unit (2) is 40 or more and less than 80, the pH of the drying mixture is set to 9 or more and 14 or less, and the mixture is dried by a thin film drying method or a spray drying method.
When the copolymer 1 is a copolymer in which n of the structural unit (2) is 80 or more, the drying mixture is dried by a thin film drying method or a spray drying method with a pH of 7 or more and 14 or less.

According to another aspect, in the present invention, when the copolymer 1 is a copolymer in which n of the structural unit (2) is less than 40, the drying mixture is dried with the pH set to 11 or more and 14 or less.
When the copolymer 1 is a copolymer in which n of the structural unit (2) is 40 or more and less than 80, the drying mixture is dried with a pH of 9 or more and 14 or less.
When the copolymer 1 is a copolymer in which n of the structural unit (2) is 80 or more and less than 100, the drying mixture is dried with a pH of 8 or more and 14 or less.
When the copolymer 1 is a copolymer in which n of the structural unit (2) is 100 or more, the drying mixture is dried with the pH set to 7 or more and 14 or less.

In the present invention, a drying mixture having a pH in the predetermined range is subjected to drying according to the average number of moles of alkylene oxide added to the copolymer 1. This pH may be the pH at which the drying mixture begins to dry. That is, in the present invention, drying can be started using a drying mixture having a pH in the predetermined range.

In the method for producing a powder dispersant composition for a water-hardening composition of the present invention, when the copolymer 1 is a copolymer in which n of the structural unit (2) is less than 40, the pH of the drying mixture is determined. From the viewpoint of easiness of powdering, it is preferably 12 or more and 13 or less.

In the method for producing a powder dispersant composition for a water-hardening composition of the present invention, when the copolymer 1 is a copolymer in which n of the structural unit (2) is 40 or more and less than 80, the pH of the drying mixture is used. Is preferably 10 or more and 13 or less from the viewpoint of easiness of powdering.

In the method for producing a powder dispersant composition for a water-hardening composition of the present invention, when the copolymer 1 is a copolymer in which n of the structural unit (2) is 80 or more, the pH of the drying mixture is determined. From the viewpoint of easiness of powdering, it is preferably 8 or more and 13 or less.
In the method for producing a powder dispersant composition for a water-hardening composition of the present invention, when the copolymer 1 is a copolymer in which n of the structural unit (2) is 80 or more and less than 100, the pH of the drying mixture is used. Is preferably 9 or more and 14 or less, and more preferably 9 or more and 13 or less, from the viewpoint of easiness of powdering.
In the method for producing a powder dispersant composition for a water-hardening composition of the present invention, when the copolymer 1 is a copolymer in which n of the structural unit (2) is 100 or more, the pH of the drying mixture is determined. From the viewpoint of easiness of powdering, it is 8 or more and 14 or less, preferably 9 or more and 14 or less, and more preferably 9 or more and 13 or less.

In the present invention, the pH of the aqueous solution of the drying mixture, for example, the copolymer 1 is adjusted with a hydroxide of an alkali metal or an alkaline earth metal from the viewpoint of one-component stability and safety and ease of powdering. It is preferable to do so. The hydroxide is preferably one or more selected from barium hydroxide, calcium hydroxide, potassium hydroxide, and sodium hydroxide, and more preferably one or more selected from potassium hydroxide and sodium hydroxide. Is.

Further, the viscosity of the drying mixture to be dried is preferably 250 mPa · s or more, more preferably 300 mPa · s or more, from the viewpoints of productivity, liquid feedability and easiness of powdering of the copolymer 1 powder. It is more preferably 350 mPa · s or more, preferably 5,000 mPa · s or less, more preferably 3,000 mPa · s or less, still more preferably 1,000 mPa · s or less.

The content of the copolymer 1 in the drying mixture is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 20% by mass or more in terms of solid content, from the viewpoint of powdering the copolymer 1. It is 50% by mass or less, more preferably 40% by mass or less.
When the drying mixture is an aqueous solution of the copolymer 1, the content of the copolymer 1 in the aqueous solution is preferably 10% by mass or more in terms of solid content from the viewpoint of pulverizing the copolymer 1. , More preferably 20% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less.

The drying mixture can further contain an anti-caking agent, such as an inorganic powder and / or an organic powder. In this case, it may be in a suspended state, but in the present invention, such an embodiment may also be referred to as an aqueous solution for convenience.

The drying mixture can be dried by heating and vacuum drying, and is preferably performed by heating and drying from the viewpoint of productivity of the dried product.

The drying mixture can be dried by a method such as a thin film drying method or a spray drying method. In the present invention, from the viewpoint of productivity, it is preferable to dry the drying mixture and the aqueous solution of the copolymer 1 by a thin film drying method or a spray drying method.

Examples of the thin film drying method include a drum drying method and a disc drying method.
Specifically, the drum dry method comprises, for example, the following process. A drying mixture such as an aqueous solution of the copolymer 1 is uniformly applied to the drying drum while rotating, and the water content is evaporated to obtain a thin film sheet molded product. Subsequently, the molded sheet is peeled off with a scraper, the sheet is wound on a drum cooled to room temperature or lower, and cooled on the drum for a certain period of time. Change to. The obtained glassy sheet is peeled off from the cooling drum with a scraper, introduced into a crusher such as a feather mill, and crushed to obtain a powder product.
In addition, the disc dry method specifically comprises the following processes. A drying mixture such as an aqueous solution of the copolymer 1 is uniformly applied to the disk while rotating to evaporate the water content to obtain a thin film sheet molded product. Subsequently, the molded sheet is peeled off with a scraper, and the peeled-off dried product is cooled to change it into a glassy substance that is easier to grind. The obtained glassy dried product is introduced into a crusher such as a feather mill and crushed to obtain a powder product.

Further, the drying mixture can be dried by a spray drying method. Specifically, the spray drying method consists of the following processes. A drying mixture such as an aqueous solution of the copolymer 1 is sprayed into a drying chamber from a sprayer such as a rotary disk nozzle, a two-fluid nozzle, or an ultrasonic nozzle, and water is separated from an effective dispersant by evaporation. In the drying mixture such as the sprayed aqueous solution of the copolymer 1, the polymer 1 becomes a powdery solid due to the evaporation of water toward the lower part of the drying chamber, and after being sent to the recovery part by blowing air, a powder separator such as a cyclone is used. Will be collected at.

The temperature at which the drying mixture is dried is preferably 100 ° C. or higher, more preferably, under normal pressure from the viewpoint of the drying property of the drying mixture, the thermal stability of the powder of the copolymer 1 and the ease of powdering. Is 120 ° C. or higher, preferably 200 ° C. or lower, and more preferably 180 ° C. or lower. On the other hand, under reduced pressure, the drying temperature is not limited, and for example, the lower limit temperature may be lower than the above. This temperature may be the temperature of the heat medium applied to the drying mixture.

Drying of a drying mixture, preferably an aqueous solution of the copolymer 1, gives a powder containing the copolymer 1. In the obtained dry powder, the content of the copolymer 1 as an effective solid content is preferably 80% by mass or more, more preferably 90% by mass or more, and preferably 99% by mass or less, more preferably 98% by mass. % Or less.

With respect to the powder containing the copolymer 1, "powder" may mean solid particles including granules, flakes, pellets, granules and the like. The shape of the powder may be fixed or irregular.

In the present invention, from the viewpoint of easiness of powdering, the monomer serving as the constituent unit (1) is methacrylic acid, the monomer serving as the constituent unit (2) is methoxypolyethylene glycol monomethacrylate, and n is 5. More than 40, the molar ratio of the structural unit (1) / structural unit (2) is 2 or more and 4 or less, the weight average molecular weight of the copolymer 1 is 40,000 or more and 60,000 or less, and the total of the copolymer 1 is The ratio of the total of the constituent units (1) and the constituent units (2) to the constituent units is 100 mol%, and it is preferable to dry the drying mixture by a spray drying method.

In the present invention, from the viewpoint of ease of powdering, the monomer serving as the constituent unit (1) is a monomer selected from methacrylic acid and acrylic acid, and the monomer serving as the constituent unit (2) is methoxypolyethylene. It is a glycol monomethacrylate, n is 40 or more and less than 80, the molar ratio of the structural unit (1) / the structural unit (2) is 1 or more and 3 or less, and the weight average molecular weight of the copolymer 1 is 30,000 or more and 50,000 or less. The total ratio of the structural units (1) and the structural units (2) to the total structural units of the copolymer 1 is 100 mol%, and it is preferable to dry the drying mixture by a spray drying method.

In the present invention, from the viewpoint of easiness of powdering, the monomer serving as the constituent unit (1) is acrylic acid, the monomer serving as the constituent unit (2) is polyoxyethylene methallyl ether, and n is 40. More than 80, the molar ratio of the constituent unit (1) / constituent unit (2) is 3 or more and 5 or less, the weight average molecular weight of the copolymer 1 is 25,000 or more and 45,000 or less, and the total of the copolymer 1 is The ratio of the total of the constituent units (1) and the constituent units (2) to the constituent units is 100 mol%, and it is preferable to dry the drying mixture by a spray drying method.

In the present invention, from the viewpoint of ease of powdering, the monomer serving as the constituent unit (1) is a monomer selected from methacrylic acid and acrylic acid, and the monomer serving as the constituent unit (2) is methoxypolyethylene. It is a glycol monomethacrylate, n is 100 or more and 150 or less, the molar ratio of the structural unit (1) / the structural unit (2) is 8 or more and 10 or less, and the weight average molecular weight of the copolymer 1 is 25,000 or more and 45,000 or less. The total ratio of the structural units (1) and the structural units (2) to the total structural units of the copolymer 1 is 100 mol%, and it is preferable to dry the drying mixture by a spray drying method.

The powder containing the copolymer 1 produced according to the present invention has an average particle size of preferably 1 μm or more, more preferably 10 μm or more, still more preferably 20 μm or more, and preferably 20 μm or more, from the viewpoint of ease of powdering. It is 90 μm or less, more preferably 80 μm or less, still more preferably 70 μm or less.

The powder containing the copolymer 1 produced according to the present invention may have a median diameter (D50) of 1 μm or more, further 25 μm or more, further 50 μm or more, and 90 μm or less, further 80 μm or less, further 70 μm or less. The median diameter (D50) uses a laser diffraction / scattering particle size distribution measuring device LA-300 (manufactured by Horiba, Ltd.) and ethanol (ethanol (95), manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) as a dispersion medium. It was measured without ultrasonic irradiation.
Further, in the powder containing the copolymer 1 produced by the present invention, the proportion of particles having a particle size of 1 μm or more and 250 μm or less may be 90% by mass or more, further 95% by mass or more, and 100% by mass or less. .. This ratio is determined by using a laser diffraction / scattering particle size distribution measuring device LA-300 (manufactured by HORIBA, Ltd.) and ethanol (ethanol (95), manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) as a dispersion medium. It was calculated based on the result of the particle size measured under irradiation.
Further, the powder containing the copolymer 1 produced according to the present invention has a median diameter (D50) of 1 μm or more, further 25 μm or more, further 50 μm or more, and 90 μm or less, further 80 μm or less, further 70 μm or less. The proportion of particles having a particle size of 1 μm or more and 250 μm or less may be 90% by mass or more, further 95% by mass or more, and 100% by mass or less. These median diameters and ratios are also measured and calculated by the same method as described above.

From the viewpoint of ease of powdering, the powder dispersant composition for a water-hardening composition produced by the present invention contains the copolymer 1 in an effective content of preferably 80% by mass or more, more preferably 90% by mass. The above, and preferably 100% by mass or less, more preferably 95% by mass or less. The powder dispersant composition for a hydraulic composition produced by the present invention may be composed of the copolymer 1.

The powder dispersant composition for a hydraulic composition produced by the present invention can contain components other than the copolymer 1. For example, it can contain a powdering aid. Examples of the powdering aid include inorganic powder. Examples of the inorganic powder include silicon oxide, a salt of silicon oxide, and a carbonate. Further, an organic powder such as polyethylene glycol can also be used. When the powdering aid is contained, the content thereof is preferably 1% by mass or more, more preferably 5% by mass or more in terms of effective content with respect to the copolymer 1 from the viewpoint of easiness of powdering. The content is preferably 40% by mass or less, more preferably 20% by mass or less. The powder dispersant composition for a water-hard composition produced by the present invention may consist of the copolymer 1 and the powdering aid.

Other components that can be contained in the powder dispersant composition for a water-hardening composition produced according to the present invention include, for example, a powder defoaming agent, a powder shrinkage reducing agent, a powder thickener, and the like. Examples of the powder defoaming agent and the powder shrinkage reducing agent include polyoxyalkylene glycol alkyl ethers. Examples of the powder thickener include cellulose derivatives such as hydroxypropylmethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose and methyl cellulose. When a component selected from a powder defoaming agent, a powder shrinkage reducing agent and a powder thickener is contained, the content thereof is preferably 1% by mass or more, more preferably 1% by mass or more, in terms of effective content with respect to the copolymer 1. Is 5% by mass or more, preferably 40% by mass or less, and more preferably 20% by mass or less. Even if the powder dispersant composition for a water-hardening composition produced by the present invention comprises a copolymer 1 and a component selected from a powder defoaming agent, a powder shrinkage reducing agent and a powder thickener. good.

In the present invention, the above-mentioned arbitrary component may be blended in the drying mixture, powdered and blended in the dispersant composition, or added to the powder of the copolymer 1 and blended in the dispersant composition. You may.

The powder dispersant composition for a hydraulic composition produced by the present invention is a powder. Here, the powder means solid particles including granules, flakes, pellets, granules and the like. The shape of the powder may be fixed or irregular.

The powder dispersant composition for a hydraulic composition produced by the present invention has an average particle size of preferably 1 μm or more, more preferably 10 μm or more, still more preferably 20 μm or more, and preferably 90 μm or less, more preferably 90 μm or less. It is 80 μm or less, more preferably 70 μm or less.

The powder dispersant composition for a hydraulic composition produced according to the present invention has a median diameter (D50) of 1 μm or more, further 25 μm or more, further 50 μm or more, and 90 μm or less, further 80 μm or less, further 70 μm or less. good.
Further, in the powder dispersant composition for a water-hard composition produced by the present invention, the proportion of particles having a particle size of 1 μm or more and 250 μm or less is 90% by mass or more, further 95% by mass or more, and 100% by mass or less. It's okay.
Further, the powder dispersant composition for a water-hardening composition produced according to the present invention has a median diameter (D50) of 1 μm or more, further 25 μm or more, further 50 μm or more, and 90 μm or less, further 80 μm or less, further 70 μm or less. The proportion of particles having a particle size of 1 μm or more and 250 μm or less may be 90% by mass or more, further 95% by mass or more, and 100% by mass or less.

According to the present invention, the powder dispersant composition for a water-hard composition produced by the method of the present invention has a median diameter (D50) of 1 μm or more and 90 μm or less, and a particle size of 1 μm or more and 250 μm or less. A powder dispersant composition for a water-hard composition having a content of 90% by mass or more and 100% by mass or less is provided. The matters described in the production method of the present invention can be appropriately applied to the powder dispersant composition for a hydraulic composition of the present invention. The preferred range of the median diameter and the proportion of particles having a particle size of 1 μm or more and 250 μm or less is the same.

INDUSTRIAL APPLICABILITY The present invention provides a powdery water-hardening composition comprising a water-hardening powder and the powdery dispersant composition for a water-hardening composition of the present invention. The matters described in the production method of the present invention and the powder dispersant composition for a hydraulic composition can be appropriately applied to the powdery hydraulic composition of the present invention.

The powdery hydraulic composition of the present invention may be a premix for a so-called hydraulic composition. The powdery hydraulic composition of the present invention is a mixture for producing a hydraulic composition such as concrete and mortar, and the powder dispersant composition for a hydraulic composition of the present invention and the hydraulic powder are previously combined with each other. Is obtained by mixing. Usually, the powdery hydraulic composition of the present invention is used by mixing with water. The powdery hydraulic composition of the present invention may be, for example, a mortar premix.

The hydraulic powder is a powder having physical properties that hardens by a hydration reaction, and examples thereof include cement and gypsum. The water-hard powder is preferably a cement such as ordinary Portoland cement, belite cement, moderate heat cement, early-strength cement, ultra-fast-strength cement, sulfate-resistant cement, and blast furnace slag, fly ash, silica fume and the like. Posoran action and / or latent hydrohardness of the above, blast furnace slag cement, fly ash cement, silica fume cement, etc. to which stone powder (calcium carbonate powder) or the like is added may be used. Here, the hydraulic powder is selected from powder having a physical property of hardening by a hydration reaction such as cement, powder having a pozolan action, powder having latent hydraulic property, and stone powder (calcium carbonate powder). In the present invention, when the powder is contained, the amount thereof is also included in the amount of the hydraulic powder. When the powder having physical properties that are cured by the hydration reaction contains a high-strength admixture, the amount of the high-strength admixture is also included in the amount of the hydraulic powder. This also applies to the mass% and mass ratio related to the mass of the hydraulic powder.

In the powdery water-hard composition of the present invention, the blending amount of the powder dispersant composition for the water-hard composition of the present invention is 0.01 part by mass or more with respect to 100 parts by mass of the water-hard powder, and further 0. It may be 1 part by mass or more, 0.2 parts by mass or more, 5 parts by mass or less, 3 parts by mass or less, and 1 part by mass or less.

According to the present invention, producing a powder dispersant composition for a water-hard composition by the production method of the present invention, and mixing the produced powder dispersant composition for a water-hard composition with a water-hard powder. A method for producing a powdery water-hard composition is provided.
The method for producing a powdery water-hard composition of the present invention includes a method for producing a powder dispersant composition for a water-hard composition of the present invention, a powder dispersant composition for a water-hard composition, and a powdery water-hard composition. The matters described in the above can be applied as appropriate.

<Example 1 and Comparative Example 1>
(1) Preparation of aqueous solution for dispersant An aqueous solution containing the following copolymer and water was prepared. This aqueous solution had a solid content concentration of 40% by mass and a pH (25 ° C.) of 3. A 48% aqueous sodium hydroxide solution (manufactured by Kanto Chemical Co., Inc.) was added thereto to adjust the pH as shown in Table 1 to prepare various aqueous solutions for dispersants. The pH of the aqueous solution and the aqueous solution for a dispersant was measured and carried out at 25 ° C. with an electrode type pH meter (manufactured by HORIBA, Ltd.). Hereinafter, the pH measurement was carried out according to the same method in other Examples and Comparative Examples. The types of copolymers used are also shown in Table 1.

<Copolymer>
Polymer A: methacrylic acid / methoxypolyethylene glycol (25) monomethacrylate = 75 mol / 25 mol (n in the formula (2) in parentheses, the same applies hereinafter), weight average molecular weight = 50 000, pH 3 (effective solid content 40% by mass, measured at 25 ° C with an electrode type pH meter, the same applies hereinafter)
Copolymer B: Acrylic acid / methacrylic acid / methoxypolyethylene glycol (45) monomethacrylate = 35 mol / 35 mol / 30 mol, weight average molecular weight = 40,000, pH 3
Copolymer C: Acrylic acid / polyethylene glycol (55) metallic ether = 80 mol / 20 mol, weight average molecular weight = 35,000, pH 3
Copolymer D: Methacrylic acid / methoxypolyethylene glycol (120) monomethacrylate = 90 mol / 10 mol, weight average molecular weight = 39,000, pH 3

<Example 1 and Comparative Example 1>
(1) Production of Powder Dispersant Composition for Water-Hard Composition by Spray Drying Method The aqueous solution for dispersant prepared as described above was spray-dried with an actual powdering facility to evaluate the drying property. The powdering equipment used was equipped with a disc atomizer, a blower, and a dryer. The dryer inlet temperature was 150 ° C, the outlet temperature was 80 ° C, the outside temperature was 20 ° C, and the disk atomizer rotation speed was 18,000 rpm. rice field. Then, it was sieved with a 1 mm mesh for removing coarse particles and foreign substances, and the passed material was used in the test as a powder dispersant composition for a hydraulic composition.

(2) Production of Powder Dispersant Composition for Hydraulic Composition by Drum Dry Method The aqueous solution for dispersant prepared as described above was made into a sheet in an actual drum drying facility. The powdering equipment used was equipped with a drying drum and a scraper, and the drying drum area was 6.2 m ² , the drying drum rotation speed was 3.1 rpm, the drying drum temperature was 130 ° C, and the outside air temperature was 30 ° C. Subsequently, the obtained sheet was cooled by an actual drum cooling facility and crushed by a feather mill. A cooling facility was installed in the vicinity of the powdering facility so that the sample sheet stripped from the drum drying facility by the scraper could continue to be transported to the cooling facility. The cooling equipment used was equipped with a cooling drum, the cooling drum area was 5.8 m ² , the cooling drum rotation speed was 1.5 rpm, the cooling drum temperature was 22 ° C, and the outside air temperature was 30 ° C. The dried product after pulverization was used in a test as a powder dispersant composition for a hydraulic composition after removing coarse particles and foreign substances with a 700 μm mesh sieve.

(3) Production of Powder Dispersant Composition for Hydraulic Composition by Disc Dry Method The aqueous solution for dispersant prepared as described above was made into a sheet by a pilot type disc drying facility. The powdering equipment used was equipped with a drying disk and a scraper, and the drying disk area was 0.4 m ² , the drying drum rotation speed was 1.5 rpm, the drying drum temperature was 140 ° C, and the outside air temperature was 30 ° C. Subsequently, the obtained dried product was cooled by a cooling facility of an actual machine type and crushed by a feather mill. The cooling / crushing equipment used had a function of blowing cold air at 10 ° C., and crushing was carried out while cooling until the surface temperature of the dried product reached about 20 ° C. The dried product after pulverization was used in a test as a powder dispersant composition for a hydraulic composition after removing coarse particles and foreign substances with a 700 μm mesh sieve.

In either method, the difference in the mesh of the sieve does not affect the final particle size. For the powder dispersant composition for a water-hard composition, the particle size distribution was measured by the above method, and the median diameter (D50; μm) and the proportion (mass%) of the particles having a particle size of 1 μm or more and 250 μm or less were measured and calculated. The results are shown in Table 1.

(4) Calculation of Yield of Powder Dispersant Composition for Water-Hard Composition The yield of powder dispersant composition for water-hard composition obtained by the above operations (1), (2) or (3) is , Calculated based on the following formula. The results are shown in Table 1 as "yield".
Yield (%) of powder dispersant composition for hydraulic composition = [X × 100] / [Y × Z]
X: Mass (g) of powder dispersant composition for hydraulic composition
Y: Mass (g) of the dispersant aqueous solution used for production
Z: Solid content (% by mass) of the aqueous solution for dispersant used for production
The solid content of the dispersant aqueous solution was calculated based on the following formula based on the mass change of 2 g of the dispersant aqueous solution collected in an aluminum cup and dried at 105 ° C. for 2 hours.
Solid content (%) of aqueous solution for dispersant = [mass of aqueous solution for dispersant after drying (g) × 100] / mass of aqueous solution for dispersant before drying (g)

In Table 1, Examples 1-1 to 1-12 showed superior yields of powder dispersant compositions for hydraulic compositions as compared with Comparative Examples 1-1 to 1-7. It is considered that this is because the drying property of the aqueous solution for the dispersant was improved by increasing the pH and the drying proceeded effectively, so that the spray drying efficiency and the pulverization efficiency were improved.
The drum-drying method has the same degree of drying property as the spray-drying method if the water content is the same, and the drum-drying method also has ancillary cooling equipment. Of course, it is considered impossible to pulverize by the spray drying method.

Claims (13)

A copolymer having a structural unit (1) represented by the following formula (1) and a structural unit (2) represented by the following formula (2), and a mixture containing water are dried to contain the copolymer. A method for producing a powder dispersant composition for a water-hardening composition, which comprises producing a powder thereof.
When the copolymer is a copolymer in which n of the structural unit (2) is less than 40, the mixture is dried by a thin film drying method or a spray drying method with a pH of 11 or more and 14 or less.
When the copolymer is a copolymer in which n of the structural unit (2) is 40 or more and less than 80, the mixture is dried by a thin film drying method or a spray drying method with a pH of 9 or more and 14 or less.
When the copolymer is a copolymer in which n of the structural unit (2) is 80 or more, the mixture is dried by a thin film drying method or a spray drying method with a pH of 7 or more and 14 or less.
A method for producing a powder dispersant composition for a hydraulic composition.

(In the formula, R ¹ and R ³ indicate the same or different hydrogen atom or methyl group, respectively, and R ² and R ⁴ are the same or different, each of which is a hydrogen atom or an alkyl group having 1 or more and 3 or less carbon atoms. , M indicates a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium or an organic ammonium, p indicates a number of 0 or more and 2 or less, q indicates a number of 0 or 1, and n indicates an average number of added moles. Indicates a number of 5 or more and 150 or less.) A copolymer having a structural unit (1) represented by the following formula (1) and a structural unit (2) represented by the following formula (2), and a mixture containing water are dried to contain the copolymer. A method for producing a powder dispersant composition for a water-hardening composition, which comprises producing a powder thereof.
When the copolymer is a copolymer in which n of the structural unit (2) is less than 40, the mixture is dried with a pH of 11 or more and 14 or less.
When the copolymer is a copolymer in which n of the structural unit (2) is 40 or more and less than 80, the mixture is dried with a pH of 9 or more and 14 or less.
When the copolymer is a copolymer in which n of the structural unit (2) is 80 or more and less than 100, the mixture is dried with a pH of 8 or more and 14 or less.
When the copolymer is a copolymer in which n of the structural unit (2) is 100 or more, the mixture is dried with a pH of 7 or more and 14 or less.
A method for producing a powder dispersant composition for a hydraulic composition.

(In the formula, R ¹ and R ³ indicate the same or different hydrogen atom or methyl group, respectively, and R ² and R ⁴ are the same or different, each of which is a hydrogen atom or an alkyl group having 1 or more and 3 or less carbon atoms. , M indicates a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium or an organic ammonium, p indicates a number of 0 or more and 2 or less, q indicates a number of 0 or 1, and n indicates an average number of added moles. Indicates a number of 5 or more and 150 or less.) The method for producing a powder dispersant composition for a hydraulic composition according to claim 2, wherein the mixture is dried by heating. The method for producing a powder dispersant composition for a water-hard composition according to claim 2 or 3, wherein the mixture is dried by a thin film drying method or a spray drying method. When the copolymer is a copolymer in which n of the structural unit (2) is 80 or more and less than 100, the mixture is dried with a pH of more than 9 and 14 or less.
The method for producing a powder dispersant composition for a hydraulic composition according to any one of claims 2 to 4. The hydraulic composition according to any one of claims 1 to 5, wherein the ratio of the total of the structural units (1) and the structural units (2) to the total structural units of the copolymer is 80 mol% or more. A method for producing a powder dispersant composition. Any one of claims 1 to 6, wherein the molar ratio of the structural unit (1) to the structural unit (2) in the copolymer is 1 or more and 10 or less in the structural unit (1) / structural unit (2). The method for producing a powder dispersant composition for a hydraulic composition according to the above item. The method for producing a powder dispersant composition for a water-hard composition according to any one of claims 1 to 7, wherein the pH of the mixture of the copolymers is adjusted with a hydroxide of an alkali metal or an alkaline earth metal. .. The method for producing a powder dispersant composition for a water-hard composition according to any one of claims 1 to 8, wherein the copolymer has a weight average molecular weight of 20,000 or more and 70,000 or less. The method for producing a powder dispersant composition for a hydraulic composition according to any one of claims 1 to 9, wherein q in the formula (2) is 1. Claim 1 for producing a powder dispersant composition for a water-hard composition having a median diameter (D50) of 1 μm or more and 90 μm or less and a particle size of 1 μm or more and 250 μm or less of 90% by mass or more and 100% by mass or less. The method for producing a powder dispersant composition for a water-hardening composition according to any one of 10 to 10. A powder dispersant composition for a water-hard composition produced by the method according to any one of claims 1 to 11, having a median diameter (D50) of 1 μm or more and 90 μm or less, and a particle size of 1 μm or more and 250 μm. A powder dispersant composition for a water-hard composition, wherein the proportion of the following particles is 90% by mass or more and 100% by mass or less. A powdery hydraulic composition obtained by blending a hydraulic powder and the powdery dispersant composition for a hydraulic composition according to claim 12.