JP2002167256A - Powder dispersant for hydraulic composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powder dispersant excellent in pumping transportation before drying and excellent in pressure and moisture resistances. SOLUTION: The powder dispersant contains a copolymer obtained by polymerizing a specific vinyl monomer (a) such as an ethylenic unsaturated carboxylic acid derivative having a polyoxyalkylene group and the specific vinyl monomer (b) such as (meth)acrylic acid, an average of addition mole number of a 2-4C oxyalkylene group or an oxystyrene group is 45-150, and the ratio of the monomer (a) to the monomer (b) is (a)/[(a)+(b)]×100 = more than 0 mol% to 45 mol% or less. At least a part of the copolymer is a multivalent metallic salt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a powder dispersant for hydraulic compounds such as cement and gypsum, particularly for grout mortar, and a hydraulic composition containing the same.

[0002]

2. Description of the Related Art As a dispersant for hydraulic compounds, monovalent metal salts of polycarboxylic acid copolymers have the advantage of high dispersibility, and are usually used as liquid products. In order to increase the quality, products in which a powdery dispersing agent is previously mixed (premixed) with a powder material such as a hydraulic compound or an aggregate have been developed. However, polycarboxylic acid-based copolymer monovalent metal salts are difficult to dry powder at room temperature, and even if dry powder can be obtained, long-term storage stability,
That is, it does not satisfy, to a high level, that it does not cause adhesion or the like due to the pressure in the package (pressure resistance), does not cause adhesion by moisture absorption, and does not cause deterioration in dispersion performance (moisture resistance) before use.

[0003] As a method for obtaining a powder dispersant, Patent 266 is disclosed.
No. 9761 discloses a method of spray-drying a liquid polycarboxylic acid copolymer and inorganic powder.
JP-A-11-310444 discloses a method in which a copolymer of polyalkylene glycol alkenyl ether having a small number of moles of alkylene oxide added and maleic anhydride is converted to a polyvalent metal salt. Japanese Patent Application Laid-Open No. 2000-26145 discloses a method in which a polymer is used in combination with a water-insoluble specific metal salt or metal hydroxide.
No. 09 discloses a method of dry-pulverizing a (meth) acrylate-based cement dispersant having a specific structure.

[0004]

When a large amount of powder dispersant is used in a factory-produced environment, and the temperature and humidity are not necessarily controlled, the pressure dispersing agent and the moisture resistance are further improved. Is desired. On the other hand, dispersing performance, in particular, it is possible to disperse the mortar of the hydraulic composition without imparting excessive viscosity to the mortar, and in particular, it is necessary to impart a proper viscosity to a large amount of powder in the field and disperse it. A powder dispersant useful for (especially for use in grout mortar) is desired. However, the conventional technology employs a means such as mixing with an inorganic powder that does not contribute to the dispersion of the hydraulic compound or containing a large amount of salt. In addition, there is a concern that the dispersion may harden or cause physical property deterioration after the dispersion is cured.

According to the present invention, a polycarboxylic acid copolymer which is hard to be dried and powdered at room temperature does not hinder pumping, etc., and is excellent in pressure resistance and moisture resistance when dryly powdered industrially. An object of the present invention is to provide a powder dispersant capable of imparting a stable dispersion state to a hydraulic composition, particularly a hydraulic composition for mortar grout.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a vinyl monomer (a) represented by the following general formula (1) and a vinyl monomer represented by the following general formula (2). A powder dispersant for a hydraulic composition containing one or more copolymers obtained by polymerizing at least one of the polymer (b), wherein the oxyalkylene group having 2 to 4 carbon atoms in the dispersant. Alternatively, the average value of the number of moles of the added oxystyrene group is 45 to 150, and the ratio of the monomer (a) to the monomer (b) is (a) / [(a) +
(B)] x 100 = more than 0 mol% and 45 mol% or less;
The present invention also relates to a powder dispersant in which at least a part of the copolymer is a polyvalent metal salt, and a hydraulic composition containing the powder dispersant and a hydraulic compound.

[0007]

Embedded image

Wherein R ¹ , R ² : hydrogen atom or methyl group R ³ : hydrogen atom or —COO (AO) _n X m: 0 to 2 p: 0 or 1 AO: carbon number 2 Oxyalkylene group or oxystyrene group of 4 to 4 n: Average number of moles added and a number of 2 to 300 X: represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms. ]

[0009]

Embedded image

[Wherein R ^{4 to} R ⁶ may be the same or different and each represents a hydrogen atom, a methyl group or (CH ₂ ) _m1 COOM ² ;
H ₂ ) _m1 COOM ² is COOM ¹ or another (CH ₂ ) _m1 COO ₂
An anhydride may be formed with M ² , in which case M ¹ and M ² of those groups are not present. M ¹ , M ² : hydrogen atom or polyvalent metal m1: represents the number of 0 to 2. ]

[0011]

DETAILED DESCRIPTION OF THE INVENTION The present inventors have paid attention to the fact that the polyvalent metal salt of a polycarboxylic acid-based dispersant can be easily dried into powder and the dispersibility does not decrease. As a result of trying to determine a structure most suitable for expressing both pressure resistance and moisture resistance in a well-balanced manner, an oxyalkylene group having 2 to 4 carbon atoms or an oxystyrene group (hereinafter referred to as a specific AO) ) And the copolymerization molar ratio M _a (mol%) of the monomer (a) in the dispersant. That is,
Pressure resistance tend to additional molar number of specific AO becomes good as M _a is reduced to increase, whereas, tends moisture resistance becomes good as the M _a number of moles increases specific AO increases I found something. Then, as a range where both the pressure resistance and humidity resistance is exhibited good balance, the average value n _M of the number of moles of a particular AO in the dispersant 45-150, the M _a 0 mole%
More than 45 mol% or less. Furthermore, in a dispersant satisfying this requirement, it is specified that a polyvalent metal salt of the copolymer is used in order to obtain excellent dry powder properties and further excellent dispersibility. Hereinafter, the monomers (a) and (b), the copolymer, and the like will be described.

<Monomer (a)> As the monomer (a) represented by the general formula (1), methoxy polyethylene glycol, methoxy polypropylene glycol, methoxy polybutylene glycol, methoxy polystyrene glycol, ethoxy polyethylene polypropylene glycol (Meth) acrylic acid, (half) esterified product with maleic acid, 3-methyl-3-butenyl alcohol, (meth)
Examples include etherified products with allyl alcohol, and (meth) acrylic acid, maleic acid, 3-methyl-3-butenyl alcohol, and ethylene oxide and propylene oxide adducts to (meth) allyl alcohol. R ³ is preferably a hydrogen atom, p is preferably 1, and m is preferably 0. AO is preferably an oxyethylene group. Monomer (a)
As such, an alkoxy, especially an esterified product of methoxypolyethylene glycol and (meth) acrylic acid is more preferable. Note that two or more monomers (a) having different n's may be used in combination. n is 5 to 200, especially 8 to 15
0 is preferred.

<Monomer (b)> The monomer (b) represented by the general formula (2) includes monocarboxylic acid monomers such as (meth) acrylic acid and crotonic acid, and maleic acid. Preferred are dicarboxylic acid monomers such as acid, itaconic acid and fumaric acid, or anhydrides or polyvalent metal salts thereof, for example, alkaline earth metal salts, and more preferably (meth) acrylic acid or a polyvalent metal salt thereof. , Maleic acid or a polyvalent metal salt thereof,
Maleic anhydride, more preferably (meth) acrylic acid or an alkaline earth metal salt thereof, particularly preferably (meth) acrylic acid.

<Copolymer> The copolymer used in the powdery dispersant of the present invention can be produced by a known method using the above monomers (a) and (b). A plurality of monomers (a) and (b) can be used respectively. Japanese Patent Application Laid-Open No. 59-162163 describes an example of the production method.
JP, JP-A-62-70250, JP-A-62-70250
No. 78137, U.S. Pat. No. 4,870,120, and U.S. Pat. No. 5,137,945 include solution polymerization methods. That is, it can be produced by combining and polymerizing the vinyl monomers (a) and (b) in an appropriate solvent in the above ratio. For example, in water or a lower alcohol having 1 to 4 carbon atoms, in the presence of a polymerization initiator such as ammonium persulfate and hydrogen peroxide, if necessary, sodium hydrogen sulfite or mercaptoethanol is added, and if necessary, 50-100 ° C under a nitrogen atmosphere. For 0.5 to 10 hours.

In producing the copolymer of the present invention, acrylonitrile, (meth) acrylamide, styrene, alkyl (meth) acrylate (having 1 to 12 carbon atoms which may have a hydroxyl group) are further used. Copolymerizable monomers such as esters, methallyl sulfonic acid, styrene sulfonic acid, phosphoethyl methacrylate, and sulfoethyl methacrylate can be used in combination, but the total of monomers (a) and (b) in the raw material monomers Is preferably 98 to 100% by weight.

The weight average molecular weight of the copolymer used in the powdery dispersant of the present invention [gel permeation chromatography, in terms of polyethylene glycol, column: G
4000PWXL + G2500PWXL (Tosoh Corporation)
Eluent: 0.2 M phosphate buffer / acetonitrile = 7/3 (volume ratio)] is preferably in the range of 6,000 to 1,000,000 from the viewpoint of dispersibility and surface hardness, and 10,000 to 200,000. Is more preferable, and 550,000 to 150,000 is even more preferable.

At least a part of the copolymer of the present invention forms a salt with a polyvalent metal. The salt may be derived from the monomer or may be formed by neutralization after the copolymerization reaction. Examples of the polyvalent metal include calcium, magnesium, and aluminum, and calcium is particularly preferred. In addition, the degree of neutralization with a polyvalent metal is preferably 5% or more, more preferably 10% or more, still more preferably 20% or more, still more preferably 40% or more, and preferably 50% or more, in consideration of dry powder properties. Most preferred. On the other hand, if the degree of neutralization is too high, the pumping property decreases due to excessive thickening. The degree of neutralization is the ratio of the total number of moles of the polyvalent metal salt to the total number of carboxyl groups in the powder dispersant. The polyvalent metal salt in the powder dispersant is subjected to inductively coupled plasma emission spectrometry. It is calculated by quantification.

In the powder dispersant of the present invention, the n _M
And _a plurality of copolymers having different M _a can be used.
Further, an acid-type copolymer which is not a polyvalent metal salt can be appropriately used in combination.

<Powder Dispersant> The obtained copolymer can be powdered by a known method and used as a dispersant. Specific examples include a spray drying method and a thin film drying method. Further, if necessary at the time of production, it is possible to powderize an organic compound and / or an inorganic compound as a carrier, but it is preferable not to use these carriers. As the organic compound, a polymer compound is preferable, and as the inorganic compound, blast furnace slag,
Silica sand, silica stone powder, fly ash and calcium carbonate are preferred. When a carrier is used, the amount in the powdery dispersant finally obtained is 1 to 80% by weight, particularly 5 to 30% by weight.
It is preferable to use it.

The average value n _{M of the} number of moles of the specific AO added to the powder dispersant of the present invention is from 45 to 150. From the viewpoint of pressure resistance and moisture resistance, n _M is 50 or more, more preferably 60 or more, and especially 70 or more.
The above is preferred. Further, from the viewpoints of pumping properties during production of the copolymer and suppression of mortar thickening, n _M is 150 or less, further 130 or less, further 115 or less, particularly 100 or less.
The following is preferred.

The ratio M _a of the total monomer (a) and the total monomer (b) in the powder dispersant of the present invention is (a) /
[(A) + (b)] × 100 = 0% to 45% by mol or less, preferably 5% by mol or more from the viewpoint of moisture resistance.
It is more preferably at least 10 mol%, particularly preferably at least 15 mol%. Further, from the viewpoint of pressure resistance, preferably 4
0 mol% or less.

Here, n _M and M _a are monomers (a),
Although it can be calculated from the charging ratio of (b), it can be determined by analyzing the final dispersant by ¹ H-NMR. In the present invention employs a n _M and M _a found by ¹ H-NMR analysis as the value of the dispersing agent.

In the present invention, a monovalent metal salt of a copolymer obtained by polymerizing one or more of the vinyl monomer (a) and one or more of the vinyl monomer (b), Preferably, a sodium salt can be used in combination. Some of the copolymers (acid type) composed of the monomers (a) and (b) or the monovalent metal salts thereof are difficult to be dried and powdered at room temperature. By using a copolymer which is a valent metal salt in combination, dry powder properties are improved. Average value n of all monomers (a) constituting the polyvalent metal salt
_MP is preferably larger than the average value n _MM of n of all monomers (a) in the copolymer (acid form) and / or its monovalent metal salt (ie, n _MP > n _MM ), and more preferably It is preferably at least one, more preferably at least two, particularly preferably at least five.

In order for the polyvalent metal salt type copolymer to be present in the powder dispersant of the present invention, the monovalent metal salt type and the polyvalent metal salt type may be mixed in advance and made into a dry powder. Alternatively, the monovalent metal salt having a low degree of neutralization may be neutralized with a polyvalent metal hydroxide to be present as a copolymer containing the polyvalent metal salt. Any method may be used as long as the union is contained.

It is desirable to add an antifoaming agent to the powdery dispersant of the present invention from the viewpoint of antifoaming properties. Examples of the antifoaming agent include lower alcohols such as methanol and ethanol, dimethyl silicone oil, and fluorocarbon. Silicone such as silicone oil, mineral oil such as a blend of mineral oil and surfactant, phosphate such as tributyl phosphate, oleic acid, sorbitan oleate monoester, sorbitan oleate monoester, polyethylene glycol fatty acid ester And fatty acid esters such as polyethylene / polypropylene glycol fatty acid esters and the like, and nonionic types such as polypropylene glycol and polyethylene / polypropylene glycol alkyl ether.
Preferably, it is a fatty acid or an ester thereof, and more preferably, a polyethylene / polypropylene glycol fatty acid ester. The addition amount of the antifoaming agent is preferably 0.01 to 10% by weight, more preferably 0.05 to 5% by weight in the powdery dispersant.
Is more preferable, and 0.1 to 3% by weight is particularly preferable.

The powdery dispersant of the present invention has a particle diameter of 500 μm or less from the viewpoint of practical water solubility.
The content is preferably 0 to 100% by weight, more preferably 70 to 100% by weight, and still more preferably 90 to 100% by weight.
% By weight.

The powdery dispersant of the present invention can be used by premixing with a hydraulic compound such as cement or gypsum, and, if necessary, with an aggregate. The premix can be used for self-leveling materials, grout for tunnels, spray mortar, non-shrink materials, refractories, gypsum plasters and the like. Examples of the hydraulic compound include Portland cement, blast furnace cement, silica cement, fly ash cement, alumina cement, natural gypsum, by-product gypsum and the like. Preferred are portland cement, alumina cement and natural gypsum, and more preferred are portland cement and alumina cement.

The powdery dispersant of the present invention is used in an amount of 0.01 to 5% by weight based on a hydraulic compound such as cement or gypsum.
Is preferable, and 0.02 to 3% by weight is more preferable.

[0029]

EXAMPLES Production Example 1 475 parts by weight of water was charged into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube and a reflux condenser, and the atmosphere was replaced with nitrogen. Subsequently, the temperature was raised to 58 ° C. under a nitrogen atmosphere, and then 295 parts by weight of methoxypolyethylene glycol monomethacrylate (monomer (a), n = 10) was added.
A solution obtained by mixing 76.7 parts by weight of methacrylic acid, and 5% -2
44.9 parts by weight of an aqueous mercaptoethanol solution and 5%
-Three liquids of 85.2 parts by weight of an aqueous solution of ammonium persulfate were simultaneously added dropwise, and the addition of all three liquids was completed in 90 minutes.
Next, after aging for 1 hour at the same temperature, 13.1 parts by weight of a 5% aqueous solution of ammonium persulfate was added dropwise over 30 minutes, and the mixture was aged for 2 hours at the same temperature. Furthermore, calcium hydroxide 5
After adding 2.7 parts by weight and neutralizing, the mixture was cooled and a copolymer having a weight average molecular weight of 36000 [Ca salt (degree of neutralization: 80%)]
(Copolymer 2 in Table 1) was obtained. Ca salts of other similar copolymers in Table 1 were prepared according to the above, with a degree of neutralization of 80 ± 10%.

Production Example 2 The same glass reaction vessel as in Production Example 1 was charged with 266 parts by weight of water and purged with nitrogen. Subsequently, under a nitrogen atmosphere, 80
After heating to 60 ° C., 60% -methoxypolyethylene glycol monomethacrylate (monomer (a), n = 12
0) 508.5 parts by weight of an aqueous solution, methoxypolyethylene glycol monomethacrylate (monomer (a), n = 9)
42.2 parts by weight of a mixture of 36.6 parts by weight of methacrylic acid and a 5% -2-mercaptoethanol aqueous solution
3 parts by weight and 51.7% aqueous solution of ammonium persulfate 51.7
Parts by weight of the three liquids were simultaneously dropped, and the dropping of all three liquids was completed in 90 minutes. Next, after aging for 1 hour at the same temperature, 5%
An aqueous solution of ammonium persulfate (25.8 parts by weight) was added dropwise over 30 minutes, and the mixture was aged at the same temperature for 2 hours. Further, the mixture was neutralized by adding 25.2 parts by weight of calcium hydroxide, and then cooled to obtain a copolymer having a weight average molecular weight of 68,000 [Ca salt (degree of neutralization: 80%)] (Copolymer 17 in Table 1). Obtained. Ca salts of other similar copolymers in Table 1 were prepared according to the above, with a degree of neutralization of 80 ± 10%.

Production Example 3 According to the method for producing a water-soluble vinyl copolymer disclosed in JP-A-7-309656, except that calcium hydroxide was used instead of sodium hydroxide, the copolymer 18 [Ca salt (Degree of neutralization 80%)].

Production Example 4 According to the production method described in paragraph 0042 of JP-A-9-309756, the copolymer 20 [Ca salt (neutralization degree of 8
0%)].

[0033]

[Table 1]

(Note) The symbols in the table are as follows. All the salts of the copolymers in the table have a degree of neutralization of 80 ± 10%. -MEPEG: methoxy polyethylene glycol monomethacrylate-METPEG: methoxy polyethylene glycol monoallyl ether-MAA: methacrylic acid-MSA: methallyl sulfonic acid-MA: maleic anhydride-Mw: weight average molecular weight.

Example 1 The copolymers shown in Table 1 were combined as shown in Table 2 to prepare dispersants, and the following evaluations were made. Table 2 shows the results. Was also measured n _M and M _a of the dispersant in the following way.

(A) A dispersant dissolved in _nM water as a dispersant and dried under reduced pressure in a nitrogen atmosphere is dissolved in heavy water at a concentration of 3 to 4%, and ¹ H-NMR is measured. From the integrated value of the peak of the alkoxy group (in this case, the methoxy group) and the integrated value of the peak of the alkylene oxide group (in this case, the ethylene oxide group), the total number of Hs in the ethylene oxide group was determined. The value obtained by dividing by the number of hydrogen atoms contained is n _M of the dispersant.
And In addition, ¹ H-NMR measurement was performed using “UNITY-INOVA500” (500 MHz) manufactured by Varian.
Using 64000 data points and 100 measurement ranges
00.0 Hz, pulse width (45 ° pulse) 60 μs
c, the pulse delay time was 30 sec, and the measurement temperature was 25.0.

(B) A dispersant dissolved in _Ma water is dried at room temperature in a nitrogen atmosphere, dissolved in heavy water, and ¹ H-NMR is measured (the conditions are the same as above). From the integrated value s of the peak of the alkoxy group (in this case, a methoxy group) and the integrated value S of the peak of the alkyl group in the main chain (in this case, a methyl group), [(S−s) / S] × 1
00 is calculated to determine the ratio M _a of the monomer of the total dispersing agent (a) and monomer (b).

(1-1) Dry Powder Property The aqueous solution of the dispersant shown in Table 1 is placed in a flat container after adjusting the concentration and amount so that the film thickness after drying is about 1 mm.
Dry at 5 ° C. for 2 hours. 40m from dry dispersant film
A test piece of mx 15 mm is prepared, a portion about 1 cm from one end in the longitudinal direction is sandwiched between fingers, and a bending force is applied by hand from the other end. This test was carried out at a predetermined thin film temperature, and the behavior at that time was observed and evaluated according to the following criteria. At that time, those that were broken by this bending force were regarded as “powderable”, and those that simply bent without breaking were regarded as “impossible to be powdered”. The temperature of the thin film was adjusted by leaving the film in a constant temperature room at a predetermined temperature for 2 hours without absorbing moisture. ：: Can be powdered at 40 ° C. ○ to ：: Can be powdered at 30 ° C., but liquid or not powdered at 40 ° C .: Can be powdered at 20 ° C., but not liquid or powdered at 30 ° C. Δ to ○: powdery at 10 ° C., but liquid or non-pulverizable at 20 ° C. Δ: non-powderable at 10 ° C. ×: liquid at 10 ° C.

(1-2) Pressure Resistance The dispersant was placed in a polyethylene bag (capacity: 250 cm ³ ).
Filled with 50 cm ³ and sealed 1000 kgf / m ²
Was left at 20 ° C. under a load. After 1 day and 7 days, the 1410 μm sieve passing rate was measured, and the pressure resistance was evaluated based on the following criteria. ：: Sieve passing rate of more than 95% and 100% or less ○ to ◎: Sieve passing rate of more than 90% and 95% or less ：: Sieve passing rate of more than 80% and 90% or less △ to ○: Sieve passing rate of more than 70% and 80% or less △: More than 50% of sieve passing rate and 70% or less ×: 50% or less of sieve passing rate.

(1-3) Moisture resistance A 300 ml beaker was charged with 50 g of a powder dispersant (pre-dried at 105 ° C. for 2 hours), and the temperature was 25 ° C. and the humidity was 40.
% In an open system for 7 days, the moisture absorption was determined from the weight change, and the moisture resistance was evaluated according to the following criteria. ◎: moisture content of 2% or less (solid content rate of 98% or more) ○ to ：: moisture content of more than 2% and 4% or less (solid content rate of 96% to 9)
O: less than 4% and 6% or less (solid content 94% or more and 96%)
Less than) △-○: Water content more than 6% and 8% or less (solid content 92% or more and 9 or less)
Δ: less than 8% and 10% or less (solid content: 90% or more and 92% or less)
%: ×: water content of more than 10% (solid content of less than 90%).

(1-4) Pumpability The viscosity of the aqueous solution of the dispersant (active ingredient 40% by weight) at 20 ° C. was measured using a B-type rotational viscometer, and the pumpability was evaluated based on the following criteria. . ：: Viscosity of 400 mPa · s or more and less than 420 mPa · s ○-◎: Viscosity of 420 mPa · s or more and less than 450 mPa · s ○: Viscosity of 450 mPa · s or more and less than 500 mPa · s Δ〜: Viscosity of 500 mPa · s or more and less than 600 mPa · s △: Viscosity 600 mPa · s or more and less than 700 mPa · s ×: Viscosity 700 mPa · s or more.

(1-5) Separation resistance Dispersant, 360 g of water, 800 g of cement, fine aggregate 180
A mortar obtained by kneading 0 g with a mortar mixer (based on JIS R5201.8) is 100 mm in upper opening opening diameter, 20 mm in lower discharging opening diameter, and 3 mm in length.
A lower frustum-shaped cylinder (mortar flow time measuring device) with a diameter of 00 mm is packed with the lower discharge opening closed, and after rubbing off the upper input opening, the lower discharge opening is opened to remove the mortar. The mortar was allowed to flow naturally, and the time (flowing time) until holes were confirmed in at least a part of the mortar when visually observed from the upper charging opening was measured. The longer the flow time, the higher the viscosity of the concrete and the stronger the resistance to material separation. In addition, the addition amount of the dispersant is determined by the mortar flow value of 29.
It was adjusted to be 0 mm ± 10 mm.

[0043]

[Table 2]

As shown in Table 2, the comparative products 1-1, 1
-3,1-4 can not powder drying small n _M of the dispersant,
Even in Comparative product 2 containing a polyvalent metal salt, if n _M is small, the pressure resistance is insufficient. Comparative product 1-5 has a large n _M and has insufficient pumping properties. On the other hand, the product 1-1 of the present invention
In Nos. 1 to 23, dry powder properties, pressure resistance, moisture resistance, pumpability, and separation resistance are all good.

Example 2 Early strength Portland cement (manufactured by Taiheiyo Cement Corporation)
100 parts by weight, fine aggregate [silica sand (mixed with 3,4,5, manufactured by Takeori Mining Works)] 100 parts by weight, thickener [Metroze (manufactured by Shin-Etsu Chemical Co., Ltd.)] 0.0025 parts by weight, delayed 0.02 parts by weight of an agent [sodium citrate (special grade reagent)], 5 parts by weight of an expanding material [DENKA CSA (manufactured by Denki Kagaku Kogyo KK)], and 0.0015 parts by weight of a foaming agent (metal aluminum powder);
The powder dispersant in Table 3 and the amount of the antifoaming agent [Formrex 797 (manufactured by Nichika Chemical Co., Ltd.)] shown in Table 3 were mixed to produce a grout material. Water was added to the grout material and kneaded with a hand mixer for 3 minutes to obtain a slurry.
The following evaluation was performed using this slurry. Table 3 shows the results.

(2-1) Fluidity Standard of PCJ Grout Test Method (JCSE-F5)
31) ", the flow time (sec) from the J14 funnel was measured. However, the flow value measured according to “JIS R 5201 Cement physical test method” is 250 m
This was carried out by adjusting the addition ratio of the powder dispersant so that m ± 10 mm.

(2-2) Bleeding rate The bleeding rate was measured in accordance with the standards of the Japan Society of Civil Engineers “PC grout test method (polyethylene bag method) (JCSE-F532)”.

(2-3) Expansion coefficient Standard of PCJ Grout test method (container method) (J
CSE-F533) ".

(2-4) Compressive strength Measured at a material age of 28 days according to “JIS R 5201 Cement physical test method”.

[0050]

[Table 3]

As shown in Table 3, when the powder dispersant of the present invention is used for mortar grout, a powder having good fluidity, bleeding rate, expansion rate and compressive strength can be obtained. In particular, when an antifoaming agent is used, the compressive strength is stabilized.
Further, in mortar grout applications, the Ca salt of the copolymer derived from the ester monomer (Nos. 2-1 to 2-4) is better than the Ca salt of the copolymer derived from the ether monomer (No. .
2-5) The flow time is longer and the separation resistance is more stable. On the other hand, No. In the case of 2-6 (comparative product), the fluidity may decrease due to excessive thickening.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08F 216/12 C08F 216/12 220/04 220/04 222/02 222/02 222/04 222/04 / / C04B 103: 40 C04B 103: 40 F term (reference) 4J100 AD07P AE18P AE21P AJ01Q AJ02Q AJ03P AJ08Q AJ09P AJ09Q AK13Q AK21Q AK32Q AL08P AL41P BA05P BA06P BA08P BA09P BC43H CA31 HA31B

Claims (3)

[Claims] 1. One or more vinyl monomers (a) represented by the following general formula (1) and one or more vinyl monomers (b) represented by the following general formula (2): And a powder dispersant for a hydraulic composition containing one or more copolymers obtained by polymerizing the oxyalkylene group or the oxystyrene group having 2 to 4 carbon atoms in the dispersant. Is 45 to 150, and the ratio of the monomer (a) to the monomer (b) is (a) / [(a) + (b)] × 100 = 0 mol%
A powder dispersant having a content of more than 45 mol% or less and wherein at least a part of the copolymer is a polyvalent metal salt. Embedded image [Wherein R ¹ , R ² : hydrogen atom or methyl group R ³ : hydrogen atom or —COO (AO) _n X m: the number of 0 to 2 p: the number of 0 or 1 AO: the number of carbon atoms of 2 to 4 Oxyalkylene group or oxystyrene group n: average number of added moles and a number of 2 to 300 X: represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms. [Chemical formula 2] [Wherein, R ^{4 to} R ⁶ may be the same or different and each is a hydrogen atom, a methyl group, or (CH ₂ ) _m1 COOM ² ;
H ₂ ) _m1 COOM ² is COOM ¹ or another (CH ₂ ) _m1 COO ₂
An anhydride may be formed with M ² , in which case M ¹ and M ² of those groups are not present. M ¹ , M ² : hydrogen atom or polyvalent metal m1: represents the number of 0 to 2. ] 2. The powder dispersant for a hydraulic composition according to claim 1, wherein all of the copolymer is a polyvalent metal salt. 3. A hydraulic composition comprising the powder dispersant according to claim 1 and a hydraulic compound.