JP7623855B2 - Dispersant composition for hydraulic powder - Google Patents

Description

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

Conventionally, naphthalene-based dispersants such as naphthalene sulfonate formaldehyde condensates have been known as dispersants for hydraulic powders such as cement. Compared to polycarboxylic acid-based dispersants, naphthalene-based dispersants have less variation in the effect of fluidity expression in response to changes in materials and temperature, and the viscosity of the resulting hydraulic composition is relatively low, making them easy to use when producing hydraulic compositions.

Patent Document 1 discloses a method for producing a slurry dispersant whose main component is a naphthalenesulfonic acid-formalin condensate, characterized in that when a sulfonation reaction solution of naphthalene and formalin are condensed under inert gas pressure, the amount of water used for condensation is adjusted to 6.5 to less than 7.5 times the total number of moles of the naphthalene compound.

Patent Document 2 discloses a water-reducing agent for hydraulic compositions that contains a naphthalenesulfonic acid formaldehyde condensate having a weight-average molecular weight of 1,900 to 24,000 as measured by gel permeation chromatography (GPC), and in which the peak area of molecular weights of 4,000 or less as measured by GPC accounts for 17 to 38% of the total peak area.

Japanese Patent Application Publication No. 11-302048 JP 2010-59045 A

Generally, naphthalenesulfonic acid formaldehyde condensates are produced by a condensation reaction between naphthalenesulfonic acid and formaldehyde in an aqueous system. The reaction product is often used as a product as an aqueous solution containing the naphthalenesulfonic acid formaldehyde condensate, either as is or with appropriate adjustments to the concentration and composition. For example, an aqueous solution containing the naphthalenesulfonic acid formaldehyde condensate or a salt thereof can be used as a dispersant composition for hydraulic powders, and in this case, it is desirable for the solution to have an appropriate viscosity.

The present invention provides a dispersant composition for hydraulic powders that contains a naphthalenesulfonic acid formaldehyde condensate or a salt thereof and has an appropriate viscosity that is easy to handle.

The present invention relates to a dispersant composition for hydraulic powder, which is prepared by blending a mixture containing a naphthalenesulfonic acid formaldehyde condensate or a salt thereof and 1,5-naphthalenedisulfonic acid or a salt thereof (hereinafter referred to as an NSF mixture) with water,
The NSF mixture contains 1,5-naphthalenedisulfonic acid or a salt thereof in a ratio of 4.0% or more and 8.0% or less in terms of a peak area of a molecular weight distribution curve of the NSF mixture measured by a gel permeation chromatography (GPC) method.
The present invention relates to a dispersant composition for hydraulic powder.

According to the present invention, a dispersant composition for hydraulic powder containing a naphthalenesulfonic acid formaldehyde condensate or its salt (hereinafter also referred to as NSF) is provided, which has an appropriate viscosity and excellent handling properties.

NSF is a condensate of naphthalenesulfonic acid and formaldehyde or a salt thereof. NSF may be co-condensed with aromatic compounds capable of co-condensing with naphthalenesulfonic acid, such as methylnaphthalene, ethylnaphthalene, butylnaphthalene, hydroxynaphthalene, naphthalenecarboxylic acid, anthracene, phenol, cresol, creosote oil, tar, melamine, urea, sulfanilic acid and/or derivatives thereof, as a monomer, as long as the performance is not impaired.

For NSF, commercially available products such as Mighty 150, Demol N, Demol RN, Demol MS, Demol SN-B, Demol SS-L (all manufactured by Kao Corporation), Celluflow 120, Labelin FD-40, Labelin FM-45 (all manufactured by Daiichi Kogyo Co., Ltd.) can be used as raw materials.

From the viewpoint of fluidizing hydraulic powder such as cement, gypsum, etc., the weight average molecular weight of NSF is preferably 6,000 or more, more preferably 8,000 or more, and preferably 25,000 or less, more preferably 19,000 or less. The weight average molecular weight of NSF can be measured by gel permeation chromatography (GPC) under the following conditions.
[GPC conditions]
Apparatus: Tosoh Corporation HLC-8320GPC
Column: Tosoh Corporation G4000SWXL + G2000SWXL
Eluent: 30mM _CH3COONa / _CH3CN =6/4
Flow rate: 0.7ml/min
Detector: UV 280 nm
Sample size: 3.33 mg/ml
Standard substance: Polystyrene sulfonate sodium conversion SCIENTIFIC POLYMER PRODUCTS, INC. SODIUM POLYSTYRENE SULFONATE-narrow distribution-: MW = 1,690, 7,540, 16,000, 68,300, 126,700, 587,600

For example, NSF can be obtained by a method of obtaining a condensation product by a condensation reaction of naphthalenesulfonic acid and formaldehyde. The condensation product may be neutralized. In addition, water-insoluble substances produced as a by-product in the neutralization may be removed. Specifically, to obtain naphthalenesulfonic acid, 1.2 to 1.4 moles of sulfuric acid are used per mole of naphthalene, and the mixture is reacted at 150 to 165°C for 2 to 5 hours to obtain a sulfonated product. Next, formalin is dropped at 85 to 95°C over 3 to 6 hours so that 1 mole of the sulfonated product has 0.90 to 0.99 moles of formaldehyde, and the condensation reaction is carried out at 95 to 105°C after the dropwise addition. Furthermore, since the aqueous solution of the obtained condensation product is highly acidic, from the viewpoint of suppressing metal corrosion of storage tanks, etc., water and a neutralizing agent can be added to the obtained condensation product and a neutralization process can be carried out at 80 to 95°C. The neutralizing agent is preferably added in an amount of 1.0 to 1.1 moles each relative to the naphthalenesulfonic acid and unreacted sulfuric acid. In addition, water-insoluble matters resulting from neutralization can be removed, preferably by separation by filtration. By these steps, an aqueous solution of a water-soluble salt of NSF is obtained. Note that when the NSF obtained by such a method contains a predetermined amount of 1,5-naphthalenedisulfonic acid or a salt thereof as specified in the present invention, it can be used as an NSF mixture as it is.

The NSF mixture is a blend of NSF and 1,5-naphthalenedisulfonic acid or a salt thereof. The NSF mixture has a content of 1,5-naphthalenedisulfonic acid or a salt thereof of 4.0% or more and 8.0% or less in peak area of a molecular weight distribution curve of the NSF mixture measured by gel permeation chromatography (GPC) under the following conditions. This content can be calculated as the ratio of the peak area corresponding to 1,5-naphthalenedisulfonic acid or a salt thereof to the total amount of peak areas of the molecular weight distribution curve of the NSF mixture.
[GPC conditions]
Apparatus: Tosoh Corporation HLC-8320GPC
Column: Tosoh Corporation G4000SWXL + G2000SWXL
Eluent: 30mM _CH3COONa / _CH3CN =6/4
Flow rate: 0.7ml/min
Detector: UV 280 nm
Sample size: 3.33 mg/ml
Standard substance: Polystyrene sulfonate sodium conversion SCIENTIFIC POLYMER PRODUCTS, INC. SODIUM POLYSTYRENE SULFONATE-narrow distribution-: MW = 1,690, 7,540, 16,000, 68,300, 126,700, 587,600

The content of 1,5-naphthalenedisulfonic acid in the NSF mixture may be, for example, 3% or more, further 4% or more, and 10% or less, further 8% or less. In the past, the content of unreacted substances and low molecular weight fractions in NSF was adjusted to improve the dispersion performance of NSF, but it was not known that 1,5-naphthalenedisulfonic acid affects the viscosity of an NSF aqueous solution, and that when the content is within a certain range, the viscosity becomes appropriate for a dispersant composition for hydraulic powder containing water.

In the present invention, the content of 1,5-naphthalenedisulfonic acid in the NSF mixture is within a specified range. When producing NSF by the above method, the content of 1,5-naphthalenedisulfonic acid in the NSF mixture tends to increase when the temperature at which sulfuric acid is dripped is lowered, the molar ratio of sulfuric acid charged is increased, etc.

The hydraulic powder dispersant composition of the present invention may contain, for example, 0.01% by mass or more, further 0.1% by mass or more, further 1.0% by mass or more, and 10% by mass or less, further 5% by mass or less, and further 3% by mass or less of the NSF mixture. This blending amount is the ratio of the total blended components (same below).

The hydraulic powder dispersant composition of the present invention can contain optional components such as, for example, an effect accelerator such as mirabilite, a setting retarder such as sodium gluconate or sucrose, and other antifoaming agents and air entraining agents.

The hydraulic powder dispersant composition of the present invention is blended with water. Water is preferred from the viewpoint of solubility in the mixing water. The hydraulic powder dispersant composition of the present invention is preferably blended with water in an amount of, for example, 20% by mass or more, further 30% by mass or more, further 35% by mass or more, and 60% by mass or less, further 50% by mass or less, further 45% by mass or less. The hydraulic powder dispersant composition of the present invention is preferably a liquid hydraulic powder dispersant composition blended with a specified NSF mixture and water.

The hydraulic powder dispersant composition of the present invention is used when dispersing hydraulic powder in water. The hydraulic powder is a powder having a physical property of hardening by a hydration reaction, and examples thereof include cement and gypsum. The hydraulic powder is preferably cement such as ordinary Portland cement, belite cement, moderate heat cement, high-early strength cement, ultra-high-early strength cement, and sulfate-resistant cement, and may also be blast furnace slag cement, fly ash cement, silica fume cement, etc., to which powder with posolan action and/or latent hydraulic properties such as blast furnace slag, fly ash cement, and silica fume cement have been added, or powder of stone (calcium carbonate powder) or the like. The hydraulic powder dispersant composition of the present invention can be used in the same manner as a normal NSF-based dispersant in the preparation of a hydraulic composition containing hydraulic powder and water.

According to the present invention, there is provided a method for producing a dispersant composition for hydraulic powder, which comprises mixing a mixture containing a naphthalenesulfonic acid formaldehyde condensate or a salt thereof and 1,5-naphthalenedisulfonic acid or a salt thereof (hereinafter referred to as an NSF mixture) with water,
The NSF mixture contains 1,5-naphthalenedisulfonic acid or a salt thereof in a ratio of 4.0% or more and 8.0% or less in terms of a peak area of a molecular weight distribution curve of the NSF mixture measured by a gel permeation chromatography (GPC) method.
A method for producing a dispersant composition for hydraulic powder is provided.
The manufacturing method can be appropriately applied to the items described in the description of the dispersant composition for hydraulic powder of the present invention. The conditions for the GPC method are as described above.

A hydraulic powder dispersant composition was prepared by blending the NSF mixture having the composition shown in Table 1 with water. The concentration of the NSF mixture in the composition was 40 mass%. The NSF mixture contained a sodium salt of a naphthalenesulfonic acid formaldehyde condensate having a weight average molecular weight of 14,000 (hereinafter also referred to as NSF-Na) and a sodium salt of 1,5-naphthalenedisulfonic acid. Table 1 shows the area percentages of NSF-Na and the sodium salt of 1,5-naphthalenedisulfonic acid in the peak area of the molecular weight distribution curve of the NSF mixture measured by the GPC method under the above-mentioned conditions.
The viscosity and storage stability of the obtained dispersant composition for hydraulic powder were evaluated. The results are shown in Table 1. The viscosity was measured at a measurement temperature of 20°C using a B-type viscometer. The viscosity was also shown in Table 1 as a relative value based on that of Example 1. The storage stability was evaluated by visually observing the appearance after storage at 20°C for 24 hours.

The difference in viscosity between the examples and comparative examples in Table 1 has a large impact on practical use, for example, as a difference in the cumulative amount of energy required for pumping, and would be recognized as an extremely large difference by those skilled in the art.

Claims (1)

A hydraulic powder dispersant composition comprising a mixture containing a naphthalenesulfonic acid formaldehyde condensate or its salt and 1,5-naphthalenedisulfonic acid or its salt (hereinafter referred to as NSF mixture) and water,
The NSF mixture is a mixture obtained by a condensation reaction of naphthalenesulfonic acid and formaldehyde, and contains 1,5-naphthalenedisulfonic acid or a salt thereof in a proportion of 6.6% or more and 8.0% or less in a peak area of a molecular weight distribution curve of the NSF mixture measured by gel permeation chromatography (GPC) ;
The naphthalenesulfonic acid formaldehyde condensate or its salt has a weight average molecular weight of 6,000 or more and 19,000 or less .
Dispersant composition for hydraulic powder.