JP2003277114A - Composite cement dispersant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a composite cement dispersant which has high dispersion performance for concrete, or the like, and high fluidity of itself, and has satisfactory handling properties on premixing. <P>SOLUTION: This powdery composite cement dispersant is obtained by carrying the following B-component on the surface of a A-component, and contains the A-component in 95 to 99.99 mass% and the B-component in 0.01 to 5 mass%, and has an angle of repose of ≤43 degrees: the A-component is dry powder consisting of a water soluble vinyl copolymer containing the following A1- component in 40 to 85 mol%, the A2-component in 15 to 60 mol% and the A3-component in 0 to 5 mol% (100 mol% in total), and having a number average molecular weight of 2,000 to 50,000: the A1-component is one or more selected from olefin monocarboxylic acid and a salt thereof; the A2-component is one or more selected from alkoxypolyethylene glycol(meth)acrylate and (meth) allylsulfonate; the A3-component is one or more selected from alkyl(meth) acrylate and hydroxyalkyl(meth)acrylate; and the B-component is inorganic powder having a specific surface area of 40 to 500 m<SP>2</SP>/g. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a composite cement dispersant used for producing mortar and concrete, particularly for producing cement-based premix products.

[0002]

2. Description of the Related Art In recent years, examples of using a dispersant containing a polycarboxylic acid type polymer as a main component as a cement dispersant capable of obtaining good fluidity even at a low water cement ratio Is increasing. However, since such a dispersant is generally produced as an aqueous solution, it is impossible to premix it into a premix product such as a plasterer material, and there is a drawback that it is more costly than a powdered dispersant in transportation and the like. there were. In addition, the powdered dispersants of naphthalene sulfonate formaldehyde condensate and melamine sulfonate formaldehyde condensate, which are widely used at present, contain the formaldehyde which is pointed out to be carcinogenic by the International Agency for Research on Cancer (IARC). Since it may be contained, a powdery dispersant containing a polycarboxylic acid polymer compound as a main component is desired from the viewpoint of safety. Therefore, as a method for producing a powdery dispersant containing a polycarboxylic acid polymer as a main component, a method of mixing an aqueous dispersant solution and an inorganic powder and spray-drying has been proposed (JP-A-6-239652). However, if pulverization is attempted satisfactorily, the mixing amount of the inorganic powder increases and the polycarboxylic acid-based polymer compound concentration decreases, or the polymer compound that is adsorbed by the inorganic powder and elutes in the concrete liquid phase is generated. Tended to decrease. Further, when an attempt is made to produce a powdery dispersant having a high concentration of a polycarboxylic acid type polymer compound, the polymer compound adheres to the inner wall of the spray dryer to lower the recovery rate of the powdery dispersant, and to prevent thermal denaturation. However, there was a problem that the dispersion performance deteriorated.

Further, a composite cement admixture prepared by coating the surface of a cement admixture powder with an inorganic powder has been proposed (JP-A-5-301751 and JP-A-7-138058).
However, since the average particle size of such an inorganic powder is relatively large, the amount of the inorganic powder required to sufficiently cover the surface of the cement admixture is large, and it is necessary to secure the predetermined dispersibility of concrete or the like. There is a problem that the amount of the composite cement admixture added increases. Further, since the particle size of the inorganic powder is large, the surface coverage of the cement admixture is low, the fluidity of the composite cement admixture itself is lowered, and the handling property during premixing is poor.

[0004]

In view of the above situation, the present inventors have conducted diligent research, and as a result, coated the surface of a polycarboxylic acid type polymer compound powder having a specific structure with an inorganic powder having a specific surface area. The present invention has completed the present invention by finding that the composite cement dispersant described above has high dispersibility for concrete and the like, high fluidity of the composite cement dispersant itself, and good handleability during premixing.

That is, the present invention is a powdery composite cement dispersant in which the following B component is supported on the surface of the A component, wherein the A component is 95 to 99.99% by mass and the B component is 0.01 to 5% by mass. % Of the composite cement dispersant having an angle of repose of 43 degrees or less: A component: 40 to 85 mol% of the following A1 component, 15 to 60 mol% of A2 component and 0 to 5 mol% of A3 component (total 100 Mol%) and a dry powder consisting of a water-soluble vinyl copolymer having a number average molecular weight of 2000 to 50,000: A1 component: one or more selected from olefin monocarboxylic acid and its salt A2 component: alkoxy polyethylene glycol One or more selected from (meth) acrylate and (meth) allyl sulfonate A3 component: One or more selected from alkyl (meth) acrylate and hydroxyalkyl (meth) acrylate B component: ratio surface area of 40~500m ² / g Inorganic powder.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below. A1
As the olefin monocarboxylic acid as a component, acrylic acid and methacrylic acid are preferable. As the olefin monocarboxylic acid salt, a salt selected from alkali metal salts such as lithium, sodium and potassium, alkaline earth metal salts such as calcium and magnesium, and organic amine salts such as diethanolamine and triethanolamine can be used.

Examples of the alkoxypolyethylene glycol (meth) acrylate as the A2 component include monoalkoxy polyethylene glycols having 1 to 3 carbon atoms such as monomethoxy polyethylene glycol, monoethoxy polyethylene glycol and mono (iso) propoxy polyethylene glycol. Examples thereof include esters with (meth) acrylic acid, and of these, methoxypolyethylene glycol (meth) acrylate having an oxyethylene group repeating number of 5 to 100 is preferable. If the number of repetitions is less than 5, the dispersibility is insufficient, and if it exceeds 100, a solid having a high melting point is formed, which makes handling difficult. As the (meth) allyl sulfonic acid salt of the component A2, an alkali metal salt, an alkaline earth metal salt, an organic amine salt of (meth) allyl sulfonic acid can be used. In the present invention, as the A2 component, one or more selected from alkoxypolyethylene glycol (meth) acrylate and (meth) allyl sulfonate can be used.

Examples of the alkyl (meth) acrylate as the A3 component include methyl (meth) acrylate and ethyl (meth) acrylate. Examples of hydroxyalkyl (meth) acrylates include 2-hydroxyethyl (meth) acrylate and 3-hydroxypropyl (meth) acrylate.

The A1 component in the A component is 40 to 85 mol%, preferably 45 to 80 mol%, the A2 component is 15 to 60 mol%, preferably 20 to 55 mol%, and the A3 component is 0 to 50 mol%. It is 5 mol%, preferably 0 to 3 mol%. Dispersion performance tends to decrease outside these ranges.

Especially from the viewpoint of dispersion performance and recovery rate, A1
Methacrylic acid or its salt as a component is 55 to 75 mol% and A
Methoxy polyethylene glycol (meth) as two components
Acrylate 25-45 mol% (A1 component and A2 component total 100
Water-soluble vinyl copolymer containing 50% to 72 mol% of methacrylic acid or a salt thereof as the A1 component, 25 to 40 mol% of methoxypolyethylene glycol (meth) acrylate as the A2 component, and (meth) allyl sulfone. A water-soluble vinyl copolymer containing 0.1 to 10 mol% of acid salt (total 100 mol% of A1 component and A2 component) is more preferable.

The water-soluble vinyl copolymer has a number average molecular weight of 20.
It is from 00 to 50,000, preferably from 3000 to 40,000. Outside this range, the dispersion performance tends to decrease. In the present invention, the number average molecular weight is a pullulan conversion value by the GPC method.

Examples of the inorganic powder as the component B used in the present invention include inorganic compounds such as silicon dioxide, aluminum oxide and tin dioxide having a specific surface area of 40 m ² / g or more. It is preferable that the adhesive force between the inorganic powders is lowered and the inorganic powder is in a free-flowing state. Specific surface area is 40
When it is less than m ² / g, the fluidity of the particles of the composite cement dispersant is not significantly improved.

As the method for producing the composite cement dispersant of the present invention, a method of mixing and agitating the water-soluble vinyl copolymer powder and the inorganic powder with a known mixer such as a Henschel mixer or a Nauta mixer, and a spray dryer are used. Immediately after producing a water-soluble vinyl copolymer powder from a water-soluble vinyl copolymer aqueous solution through a nozzle or a disk atomizer, a method of coating the surface of the powder with an inorganic powder gradually introduced through another nozzle Can be mentioned. When using a spray dryer, the drying conditions are preferably hot air inlet temperature 150 to 250 ° C and hot air outlet temperature 80 to 150 ° C. If the hot air inlet temperature is lower than 150 ° C, the productivity will decrease, and if it exceeds 250 ° C, the thermal denaturation will cause the dispersion performance to decrease. If the hot air outlet temperature is lower than 80 ° C, the powder has a high water content and is apt to cause blocking.

The thus-obtained composite cement dispersant of the present invention has a high fluidity of the powder itself, is easy to handle, and has a small angle of repose (JISR1600 injection method) of 43 degrees or less. .

Examples of the cement to which the powdery dispersant of the present invention can be used include ordinary Portland cement, early strength Portland cement, moderate heat Portland cement, high belite Portland cement, blast furnace cement, fly ash-containing cement and silica fume-containing cement. . If necessary, the powdery cement dispersant according to the present invention may be used together with an additive such as a hardening accelerator, a retarder, a thickener, a waterproofing agent, a shrinkage reducing agent, a swelling agent, an antifoaming agent and an AE agent. You can also

Embodiments of the present invention include the following 1) to 1
0) can be mentioned. 1) In a spray dryer equipped with a disk atomizer in the spraying device part, while maintaining the hot air inlet temperature at 200 ° C., sodium methacrylate / methoxy polyethylene glycol (n = 23) methacrylate 70/30 (mol%)
Number average molecular weight 22 obtained by the copolymerization reaction at a ratio of
Obtained by mixing 99.95 parts of water-soluble vinyl copolymer powder P1 spray-dried with 500 aqueous solution of vinyl copolymer a1 and 0.05 parts of silicon dioxide having a specific surface area of 200 m ² / g. Composite cement dispersant P with angle of repose of 35 degrees
B1.

2) It is obtained by mixing 99.90 parts of the powder P1 of the water-soluble vinyl copolymer by spray-drying in the same manner as 1) and 0.10 part of silicon dioxide having a specific surface area of 200 m ² / g. Composite cement dispersant PB2 with an angle of repose of 32 degrees.

3) Obtained by mixing 99.75 parts of powder P1 of a water-soluble vinyl copolymer by spray-drying in the same manner as in 1) above and 0.25 part of silicon dioxide having a specific surface area of 200 m ² / g. Composite cement dispersant PB3 with an angle of repose of 25 degrees.

4) In a spray dryer, calcium methacrylic acid salt / methoxy polyethylene glycol (n = 45) methacrylate / methallyl sulfonic acid sodium salt = 60
99 of powder P2 of water-soluble vinyl copolymer obtained by introducing an aqueous solution of a vinyl copolymer a2 having a number average molecular weight of 30,000 obtained by a copolymerization reaction at a ratio of / 35/5 (mole% ratio) and spray drying. A composite cement dispersant PB4 having a repose angle of 35 degrees obtained by mixing 0.75 part of 0.25 part of silicon dioxide having a specific surface area of 110 m ² / g.

5) In a spray dryer, sodium methacrylate / methoxy polyethylene glycol (n = 23) methacrylate / methallyl sulfonic acid sodium salt = 55 /
99. of the water-soluble vinyl copolymer powder P3 obtained by introducing an aqueous solution of a vinyl copolymer a3 having a number average molecular weight of 27,000 obtained by a copolymerization reaction at a ratio of 30/15 (mole% ratio) and spray-drying. A composite cement dispersant PB5 having a repose angle of 30 degrees obtained by mixing 50 parts with 0.50 part of silicon dioxide having a specific surface area of 110 m ² / g.

6) In a spray drier, methacrylic acid sodium salt / methoxy polyethylene glycol (n = 45) methacrylate / acrylic acid methyl ester = 60/37
Of a water-soluble vinyl copolymer powder P4 obtained by introducing an aqueous solution of a vinyl copolymer a4 having a number average molecular weight of 7,000 obtained by a copolymerization reaction at a ratio of / 3 (mole% ratio) and spray drying.
3. of titanium dioxide having 7.00 parts and a specific surface area of 50 m ² / g.
Composite cement dispersant PB6 having a repose angle of 28 degrees obtained by mixing 00 parts.

7) A ratio of sodium acrylate / methoxy polyethylene glycol (n = 23) methacrylate / methallyl sulfonic acid sodium salt / hydroxyethyl methacrylate = 60/30/6/4 (mol% ratio) in a spray dryer. Number average molecular weight 2 obtained by copolymerization reaction with
95.50 of water-soluble vinyl copolymer powder P5 obtained by introducing an aqueous solution of 6500 of vinyl copolymer a5 and spray-drying
Parts and 4.50 parts of titanium dioxide having a specific surface area of 50 m ² / g, a composite cement dispersant PB7 having a repose angle of 27 degrees.

8) Vinyl having a number average molecular weight of 22,500 obtained by copolymerization reaction in a spray dryer at a ratio of sodium methacrylic acid salt / methoxypolyethylene glycol (n = 23) methacrylate = 70/30 (mole% ratio). 99.75 parts of a water-soluble vinyl copolymer powder P1 obtained by introducing an aqueous solution of the copolymer a1 and spray-drying it and a specific surface area of 50 m ² /
Composite cement dispersant PB8 having an angle of repose of 30 degrees, obtained by mixing 0.25 part of aluminum oxide (g).

9) In a spray dryer, calcium methacrylic acid salt / methoxy polyethylene glycol (n = 45) methacrylate / methallyl sulfonic acid sodium salt = 60
99 of powder P2 of water-soluble vinyl copolymer obtained by introducing an aqueous solution of a vinyl copolymer a2 having a number average molecular weight of 30,000 obtained by a copolymerization reaction at a ratio of / 35/5 (mole% ratio) and spray drying. A composite cement dispersant PB9 having an angle of repose of 32 degrees obtained by mixing 0.75 part and 0.25 part of aluminum oxide having a specific surface area of 50 m ² / g.

10) In a spray dryer, sodium methacrylic acid salt / methoxy polyethylene glycol (n = 23)
Methacrylate / methallyl sulfonic acid sodium salt = 5
Of a water-soluble vinyl copolymer powder P3 obtained by introducing an aqueous solution of a vinyl copolymer a3 having a number average molecular weight of 27,000 obtained by a copolymerization reaction at a ratio of 5/30/15 (mole% ratio) and spray drying. The angle of repose obtained by mixing 99.75 parts and 0.25 part of aluminum oxide having a specific surface area of 50 m ² / g is 3
2 degree composite cement dispersant PB10.

[0026]

EXAMPLES Synthesis Example 1 (Synthesis of Water-Soluble Vinyl Copolymer a1) 590 parts of water was charged into a 200 L glass-lined reaction vessel and heated while stirring to keep the internal temperature at 60 ° C. A reaction vessel containing a mixture of methacrylic acid 60 parts, methoxypolyethylene glycol (oxyethylene group repetition number n = 23) methacrylate 334 parts and 3-mercaptopropionic acid 4.7 parts and 25% 20% aqueous sodium persulfate solution for 2 hours. Was added dropwise. Next, add 10 parts of a 20% aqueous sodium persulfate solution to 3 parts.
Drop over 0 minutes, age at the same temperature for 2 hours, and then at 80 ℃
The temperature was raised to and aged for 2 hours. Next, 58 parts of 48% NaOH was added dropwise while flowing cooling water to the jacket to neutralize the reaction solution. This reaction liquid was a water-soluble vinyl copolymer having a number average molecular weight of 22,500, which was obtained by copolymerizing methacrylic acid at a ratio of 70 mol% and methoxypolyethylene glycol (n = 23) methacrylate at a ratio of 30 mol% (total 100 mol%). Was an aqueous solution containing 40% by mass.

Synthesis Examples 2 to 5 (water-soluble vinyl copolymer a2 to
Synthesis of a5) In the same manner as in Synthesis Example 1, water-soluble vinyl copolymers a2 to a5 were synthesized. Table 1 shows the types of monomers, the reaction ratio, the number average molecular weight of the water-soluble vinyl copolymer, and the concentration of the water-soluble vinyl copolymer.

[0028]

[Table 1]

M1: sodium methacrylic acid salt M2: calcium methacrylic acid salt M3: sodium acrylate M4: methoxy polyethylene glycol (n = 23) methacrylate M5: methoxy polyethylene glycol (n = 45) methacrylate M6: methallyl sulfonic acid sodium salt M7: Hydroxyethyl methacrylate M8: Acrylic acid methyl ester

Preparation Example 1 (Production of Water-Soluble Vinyl Copolymer Powder P1) A spray dryer having a tower diameter of 3.2 m and a height of 7.9 m was used as a spray dryer, and a disk atomizer was used as a spray device.
While maintaining the hot air inlet temperature at 200 ° C, the disk atomizer rotation speed was 24000 rpm and the water-soluble vinyl copolymer a1
Was spray-dried at a flow rate of 125 kg / hr.

Preparation Example 2 (Water-soluble vinyl copolymer powder P2-
Production of P5) In the same manner as in Preparation Example 1, water-soluble vinyl copolymer powder P2
P5 was manufactured. Table 2 shows the residual water content, average particle size, and angle of repose of the obtained water-soluble vinyl copolymer powder.

[0032]

[Table 2]

Example 1 (Production of composite cement dispersant) In a 50 L Henschel mixer, 99.95 parts of the water-soluble vinyl copolymer powder P1 and 0.05 of silicon dioxide B1 having a specific surface area of 200 m ² / g were added.
Parts were mixed and mixed for 30 seconds to produce a composite cement dispersant.

Examples 2-10, Comparative Examples 1-3 A composite cement dispersant was produced in the same manner as in Example 1.
It was Type and mixing ratio of A component and B component, composite cement dispersion
Table 3 shows the angle of repose of the agent. Specific surface area of A component is 40m ²/ g or less
Composite cement component carrying component B which is the above inorganic powder
The powder has a low angle of repose and improved handling.
You can see that

[0035]

[Table 3]

B1: Silicon dioxide having a specific surface area of 200 m ² / g (hydrophobic) Trade name; AEROSIL R972 (manufactured by Nippon Aerosil Co., Ltd.) B2: Silicon dioxide having a specific surface area of 110 m ² / g (hydrophilic) Trade name; AEROSIL R200 (Manufactured by Nippon Aerosil Co., Ltd.) B3: titanium dioxide with a specific surface area of 50 m ² / g Product name: titanium dioxide P25 (manufactured by Nippon Aerosil Co., Ltd.) B4: aluminum oxide with a specific surface area of 50 m ² / g Product name: aluminum oxide C (Japan Aerosil Co., Ltd.) B5: Calcium carbonate with a specific surface area of 0.8 m ² / g (Reagent Grade 1 Kanto Chemical Co., Inc.) B6: Silica fume with a specific surface area of 20 m ² / g Product name: (Microsilica # 940 Elchem Japan Co., Ltd.) B7: Aluminum oxide with a specific surface area of 0.5 m ² / g (reagent grade 1
(Kanto Chemical Co., Ltd.)

Test Example (Paste Flow Test) A performance test of the obtained composite cement dispersant was conducted as follows. 27 parts by weight of water is added to 100 parts by weight of ordinary Portland cement, and a composite cement dispersant is added at room temperature of 20 ° C. and mixed for 3 minutes using a Hobart mixer to prepare a paste, and a flow value is measured. did. Table 4 summarizes the types of composite cement dispersants, the amounts added, the remixing, and the flow values after 60 minutes. (Flow measurement method) PVC pipe with an inner diameter of 50 mm and a height of 51 mm on a polished glass plate with a thickness of 5 mm (internal volume 100 m
Place l), fill the prepared paste and pull up the pipe. After the spread was stopped, the diameters in two directions at right angles were measured and the average value was used as the flow value.

[0038]

[Table 4]

P6: Powder product of naphthalene sulfonate formaldehyde condensate P7: Powder product of melamine sulfonic acid formaldehyde condensate

[0040]

EFFECTS OF THE INVENTION The composite cement dispersant of the present invention has high dispersibility for concrete and the like, high fluidity of the composite cement dispersant itself, and good handleability during premixing.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08F 220/26 C08F 220/26 228/02 228/02 290/06 290/06 // C04B 103: 40 C04B 103: 40 (72) Inventor Masaki Ishimori 2-4, Daisaku, Sakura-shi, Chiba Central Research Institute, Taiheiyo Cement Co., Ltd. (72) Inventor Mitsuo Kinoshita 2-5 Minatomachi, Gamagori-shi, Aichi Takemoto Yushi Co., Ltd. 72) Inventor Takeshi Kamoto No. 2-5 Minatomachi, Gamagori-shi, Aichi Takemoto Yushi Co., Ltd. F-term within the company (reference) 4J027 AC02 AC03 AC06 AJ02 BA06 BA07 BA08 CC02 CD09 4J100 AJ02P AK00P AK07P AK08P AK12P AL03R AL08Q ALQ CA08Q BAQQ AP08Q BAQQ AP08Q BAQQ08 AP05Q. DA01 JA05 JA67

Claims (5)

[Claims] 1. A powdery composite cement dispersant comprising the following component B supported on the surface of component A, wherein component A is 95
~ 99.99% by mass, 0.01 to 5% by mass of B component, the angle of repose is 43
Cement Dispersant Below Degree: A component: 40-85 mol% of the following A1 component, 15-60 mol% of A2 component and 0-5 mol% of A3 component (total 100 mol%), and number average Dry powder consisting of water-soluble vinyl copolymer having a molecular weight of 2000-50000: A1 component: one or more selected from olefin monocarboxylic acid and its salt A2 component: alkoxypolyethylene glycol (meth) acrylate and (meth) One or more selected from allyl sulfonate A3 component: One or more selected from alkyl (meth) acrylate and hydroxyalkyl (meth) acrylate B component: Specific surface area 40 to 500 m ² / g Inorganic powder. 2. The composite cement dispersant according to claim 1, wherein the component A is a dry powder obtained by spray drying. 3. The composite cement dispersant according to claim 1, wherein the component B is an inorganic powder selected from silicon dioxide, titanium dioxide and aluminum oxide. 4. A component is 55 to 75 mol% of methacrylic acid or a salt thereof as an A1 component and 25 to 45 mol of methoxypolyethylene glycol (meth) acrylate as an A2 component.
The composite cement dispersant according to any one of claims 1 to 3, which is a dry powder made of a water-soluble vinyl copolymer containing 100% (total of 100 mol% of A1 component and A2 component). 5. The component A comprises methacrylic acid or a salt thereof as the component A1 in an amount of 50 to 72 mol%, and methoxypolyethylene glycol (meth) acrylate as the component A2 in an amount of 25 to 40 mol%.
4. A dry powder comprising a water-soluble vinyl copolymer containing 0.1 to 10 mol% of (meth) allyl sulfonate (total 100 mol% of A1 component and A2 component). Composite cement dispersant.