JP2002348162A - Manufacturing method of powdery cement dispersant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of powdery cement dispersant, where in solidifying and pulverizing a dispersant comprising a liquid polycarboxylc acid-based polymer as a major component, pulverizing after drying can be easily done even in finely pulverizing stage with high pulverization efficiency and high manufacturing yield without any damage to its dispersing property. SOLUTION: In abtainig the dispersant, a liquid polycarboxylic acid-based polymer is dried and coarsely crushed mainly by cutting and/or shearing. The resulting product is pulverized to have a diameter of <=1 mm or made to have the crystallinity of polycarboxylic acid-based polymer in the dried product of >=35%, and then pulverized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a polycarboxylic acid-based powdery cement dispersant.

[0002]

2. Description of the Related Art A composition using cement such as concrete or mortar is practically advantageous for hardenability and mechanical properties after hardening. Therefore, it is preferable to reduce the amount of compounding water to cement. At that time, a cement dispersant is used to ensure good fluidity and workability, and a dispersant mainly composed of a polycarboxylic acid-based polymer compound capable of providing extremely good fluidity at a low water cement ratio. The use of is increasing. Since this polycarboxylic acid-based dispersant is synthesized and produced as a liquid, it is added at the time of mixing with cement and other components or at the time of mixing water with solid components. Therefore, it is impossible to pre-blend it into a premix product, etc., and there are many restrictions on storage and transportation, and furthermore, complicated preparation work on site is required. A powder form is desired. In order to obtain a powdery dispersant, not limited to a polycarboxylic acid type, generally, a liquid dispersant is dried, and the dried product is crushed and pulverized.

However, a dispersant containing a liquid polycarboxylic acid-based polymer as a main component has a remarkable increase in viscosity during the drying process, and is apt to aggregate. Pulverization is not easy, a large amount of deposits easily remain in the processing apparatus, and the production yield is low. It is also known to mix a large amount of inorganic powder such as blast furnace slag and silica fume with a liquid polycarboxylic acid-based dispersant to suppress the increase in viscosity (Japanese Patent No. 2669761).
The properties as a cement dispersant tend to decrease. Without using such an inorganic powder, a highly viscous material can be dried, for example, using a dynamic drying device that can uniformly and highly efficiently dry the material, and if it is sufficiently dried, a dried product with reduced adhesive force can be obtained. it can.

[0004]

However, even if the adhesive force is reduced, the dried product of the polycarboxylic acid-based polymer material generally has a high elasticity property, and this serves as a buffering effect of the pulverization, and the pulverization progresses. Along with, especially in the pulverization and pulverization stage,
The energy acting as a buffering action also increases, and the progress of the grinding is slowed down, and the grinding efficiency is rapidly reduced. When the pulverizing power is increased and the pulverizing process is continued, the heat generated by the pulverization increases, and the heat is accumulated, and there is a risk that the pulverized material becomes high temperature and undergoes thermal deterioration. The present invention solves such a problem, that is, in forming a solid powder of a dispersant containing a liquid polycarboxylic acid-based polymer compound as a main component, it is possible to easily perform pulverization after drying even in a fine pulverization stage. It is an object of the present invention to provide a method for producing a powdery dispersant which can be performed with high grinding efficiency and high powder production yield and which does not impair the properties of a polycarboxylic acid-based cement dispersant at all.

[0005]

Means for Solving the Problems The inventors of the present invention have made various studies to achieve the above-mentioned object. As a result, the present inventors have found that a liquid polycarboxylic acid-based polymer compound which generally forms a relatively strong aggregate when dried is used. The dried product of the dispersant, which is the main component, is crushed by a device that grinds mainly by shearing or cutting in order to suppress the action due to its adhesiveness and elasticity, and further crushes the crushed material without exerting as much wear or crushing action as possible. If the elastic properties are reduced as much as possible by finely pulverizing with a machine or by increasing the crystallinity of the polycarboxylic acid-based polymer compound in the dried product, the pulverization can easily proceed to a desired particle size and a high yield. Thus, the present invention was completed because the obtained powder did not impair the properties of the cement dispersant at all.

That is, the present invention is a method for producing a powdery cement dispersant represented by the following (1) to (6). (1) Drying a cement dispersant containing a liquid polycarboxylic acid polymer as a main component, crushing the dried product mainly by cutting and / or shearing, and then crushing the crushed product to 1 mm or less. A method for producing a powdery cement dispersant, which is characterized in that: (2)
The above (1), in which the degree of crystallinity of the polycarboxylic acid-based polymer compound in the crushed product is increased to 20% or more, and crushed to 1 mm or less.
Production method of powdery cement dispersant. (3) The method for producing a powdery cement dispersant according to the above (1) or (2), wherein the crushed material is crushed to 1 mm or less at a temperature of 10 ° C. or less. (4) Drying a cement dispersant containing a liquid polycarboxylic acid-based polymer as a main component, making the crystallinity of the polycarboxylic acid-based polymer in the dried product 35% or more, and pulverizing the same. A method for producing a powdery cement dispersant, which is characterized in that: (5) Keep the temperature of the dried product below 5 ° C
mm. (6) The method for producing a powdery cement dispersant according to any one of (1) to (5), wherein the polycarboxylic acid-based polymer compound is a (meth) acrylic acid-based copolymer or a maleic acid-based copolymer.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The cement dispersant containing a polycarboxylic acid polymer as a main component used in the production method of the present invention mainly comprises a liquid polycarboxylic acid polymer commonly used in cement dispersants. It is not particularly limited as long as it is a component, and examples thereof include (meth) acrylic acid-based copolymers and maleic acid-based copolymers (excluding polyvalent metal salts) disclosed in JP-A-2000-26145. Can be. More preferably, a cement dispersant containing a polycarboxylic acid-based polymer compound having a polyalkylene glycol chain as a main component is used.

As the (meth) acrylic acid-based copolymer,
A preferred example is a (meth) acrylic acid-based copolymer having a -COOM group (M represents a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium or an organic amine) and a polyalkylene glycol chain. Can,
Preferred examples of the maleic acid-based copolymer include a polyalkylene glycol alkenyl ether-maleic anhydride copolymer (excluding polyvalent metal salts). Any of the polyalkylene glycol chains has a structure of -O (CH ₂ CH
Those represented by (R) O) _b- are desirable. (R represents a hydrogen atom or a methyl group, b is 2 to 300, preferably 5 to 109.) Preferable specific examples are as follows.

Methacrylic acid-methoxy polyethylene glycol methacrylate copolymer, methacrylic acid-methoxy polyethylene glycol methacrylate-sodium methallylsulfonate copolymer, methacrylic acid-methoxy polyethylene glycol methacrylate-sodium metal sulfonate-acrylic acid ester copolymer A maleic acid-methoxypolyethylene glycol allyl ether copolymer, a maleic acid methoxypolyethylene glycol-styrene copolymer, a methacrylic acid-hydroxypropyl methacrylate copolymer, and an acrylic acid-hydroxyethyl acrylate copolymer.

The above-mentioned cement dispersant containing a polycarboxylic acid polymer as a main component is dried. The drying method may be such that the moisture content is about 2% or less. The drying device to be used is not particularly limited, but a device having a mechanism with less adhesion of dried matter in the device is recommended. Specifically, a Henschel type dryer, a vacuum kneader, a drum dryer, a groove type stirring and drying device, etc. are exemplified. Although the form of the dried product is not limited, the method of the present invention can be sufficiently applied to a case where a lump of a solidified solid product, which generally occurs easily, is formed of a polycarboxylic acid-based polymer compound which becomes highly viscous with drying.

The dried product is roughly crushed by a device having a mechanism for crushing the material to be crushed mainly by cutting and / or shearing. When the object to be ground is mainly crushed by cutting and / or shearing, it is difficult to completely eliminate other factors of action with known crushing means and devices, so that cutting and / or shearing is dominant. It is only necessary that other factors have little effect on the actual pulverization progress. The crushing is performed by such a crushing action because the dried product has an elastic property in addition to the adhesiveness of the dried product to some extent.
Grinding by action such as compression is not suitable because the grinding efficiency is significantly reduced. In the pulverization by the cutting and / or shearing action, the adhesion and elasticity of the object to be pulverized are hardly affected, and the pulverization can be easily performed, and the reduction in the pulverization efficiency hardly occurs. The crushing in the present invention is preferably performed until a crushed product having a particle size of about 10 mm or less is obtained. Examples of the pulverizing device suitable for the coarse pulverization include a pulverization type granulator and a pulverization type granulator. When all the particles have a particle size of 10 mm or less, the progress of the fine-graining rapidly slows down even if the crushing treatment is further performed. Accordingly, a powder having a particle size of about 1 mm or less, which is desirable as a powdery cement dispersant, more preferably a powder having a particle size of 10 to 600 μm,
In order to reduce the size, it is necessary to further grind the crushed material.

In the present invention, the pulverization of the crushed product is performed by any of the following procedures. That is, the first method is a method in which the coarsely crushed material obtained in the previous step is finely pulverized by a specific crusher as it is. The crusher used here is preferably a pin mill capable of continuously collecting the crushed material outside the crushing chamber during crushing,
More preferably, it is a rotary pin mill. Pin mills are suitable for fine pulverization and sizing of the pulverized material.Since the pulverization proceeds by the interaction of the impact and repulsion between the pulverized material and the pin, the action such as abrasion and compression is weak. In addition, the impact force and the number of collisions with the pins are increased, and the material to be ground having adhesiveness or elasticity can be finely ground almost without delay. In particular, by using a pin mill with a collection mechanism outside the crushing chamber during crushing, it is possible to sufficiently prevent the crushed material itself from becoming a crush buffer,
Since generation and accumulation of heat of grinding can be suppressed, heat denaturation and viscosity re-rise hardly occur. Therefore, if the crushed material is crushed using such a crusher so as to have a particle size of 1 mm or less,
A powdery cement dispersant can be obtained.

In a second method of pulverizing the crushed material, the crushed material obtained by the crushing treatment is made to have a crystallinity of the polycarboxylic acid type polymer compound in the crushed material of 20% or more, and this is reduced to 1 mm.
Finely pulverize below. In this case, any pulverizing apparatus can be used as long as it is used in a general pulverizing process. Among them, the rotary type pin mill used in the first method is preferable because particularly high pulverization efficiency can be obtained. In addition, a simple method of setting the degree of crystallinity of the polycarboxylic acid-based polymer compound in the crushed product to 20% or more is to cool the crushed product. The crystallinity of the dried polycarboxylic acid-based polymer compound rapidly increases at a low temperature, and is slightly reduced depending on the composition even at the same temperature. The cooling method is not particularly limited. When the crystallinity is increased to 20% or more, the elastic state of the crushed material is lost to a degree suitable for crushing,
Since the plastic state advances, fine grinding, which generally requires a large amount of energy, also easily proceeds. In addition, the adhesion is also reduced, the adhesion and accumulation on the inner wall of the crushing device and the crushing medium are extremely small, and the adhesion and bonding of the crushed materials are hard to occur. Since the crystallinity decreases with an increase in the temperature of the material to be pulverized, it is desired to perform a fine pulverization treatment immediately after cooling. When a long time of pulverization is required and the object to be pulverized is in a high temperature state due to accumulation of the pulverization heat, it can be coped with by cooling the pulverizer itself.

It is also possible to increase the crystallinity of the polycarboxylic acid-based polymer compound in the dried product before the crushing step, and crush it. In this case, if the crystallinity is set to 35% or more, and preferably the temperature of the dried product is set to approximately 5 ° C. or less, the crushing means is not limited, and any known crushing method can be applied. It is also possible to proceed to pulverization of 1 mm or less directly by one pulverization without dividing into steps.
The dried product having a high degree of crystallinity is quite strong, requires high pulverization energy to increase the pulverization efficiency, and generates a large amount of heat at the time of pulverization.

The fine powder obtained through any of the above pulverization treatments is
If necessary, a known classifying operation can be performed to obtain a powdery cement dispersant containing a polycarboxylic acid-based polymer compound having a desired particle size and particle size range as a main component.

[0016]

EXAMPLES Example 1 A powdery cement dispersant was produced by the following method using the following aqueous solution [A]. [A] Methacrylic acid 63 mol%, methoxy poly (n =
40) ethylene glycol methacrylate 3 mol%,
Methoxy poly (n = 23) 18 mol% ethylene glycol methacrylate, sodium methallylsulfonate 1
A total of about 1% by weight of sodium sulfite and triethanolamine are added to a polymer compound having a weight average molecular weight of 44000 obtained by copolymerizing 5% by mole and 1% by mole of methyl acrylate, and sodium hydroxide having a pH of 8.
An aqueous solution having a solid content of 50.0% by weight, which was added so as to be 5.

<Drying of the Liquid> A commercially available vacuum kneading type drier (double-arm type kneading machine, Co., Ltd.) having a capacity of 100 liters provided with a steam heating jacket on the outer periphery of the drying vessel was used for each 80 liters of the aqueous solution of [A]. The drying was performed while keeping the jacket temperature at 120 ° C., reducing the pressure in the vessel to 30 Torr, and kneading at a stirring rotation speed of 60 rpm. Drying was stopped when the water content of the dried product became 1.0% by weight or less. The moisture content of the dried product was measured using a commercially available moisture meter (model FD, manufactured by Kett Scientific Research Institute).
-600). The obtained dried product was aggregated in a lump. In addition, adhesion of extremely thin dried material was observed in the drying device. The remaining dry matter was taken out of the apparatus without forcibly removing the attached matter.

<Crushing of dried product>
After the temperature was kept at 0 ° C., it was pulverized at a processing speed of 100 kg / H with a crushing type granulator (trade name: Power Mill P-3 type, manufactured by Showa Giken Co., Ltd.) having a punch hole of 6 mm and a particle size of 6 mm.
The following crude product was obtained.

<Pulverization of the crushed material>
After maintaining the temperature at 0 ° C., pulverizing was performed at room temperature (about 20 ± 1 ° C.) using a high-speed rotating pin mill (trade name: Coroplex 160Z, manufactured by Hosokawa Micron Corporation) (processing conditions: rotation speed 18000 rpm, number of pins 400). Book). The pin mill has a structure in which crushed materials are collected in a collector (chamber) provided outside the crushing chamber during crushing, and the crushing particle size can be adjusted by the number of rotations and the number of pins used without providing a screen or the like. Mechanism. The pulverized product taken out of the chamber was passed through a sieve to recover a powder having a particle size of 600 μm or less. The processing amount of the material to be pulverized by the pin mill for 10 minutes was 7.5 kg. Also, the result of calculating the yield (= 100 × WP / WD) from the value of the weight of the dried material subjected to the crushing: WD and the weight of the powder having a particle diameter of 600 μm or less recovered through the above-mentioned treatments: WP. , 98%.

<Properties of Powder> Obtained Powder 0.54
g, 900 g of ordinary Portland cement, 1350 g of JIS standard sand, and 360 g of water were charged all at once into a Hobart mixer and kneaded for 210 seconds to prepare a mortar. Then, place a mortar flow cone on a glazing plate glass having a thickness of only 5 mm and fill the cone with the adjusted mortar,
The flow cone was pulled up, and when the spread of the mortar on the plate glass stopped, the diameters of the spread in two orthogonal directions were measured, and the average value was used as a flow value, and the properties as a cement dispersant were confirmed from the flow value. As a result, the flow value was 231 mm. For comparison, 1.08 g of a 50% solid content aqueous solution of non-pulverized [A], ordinary Portland cement 900 g, JIS standard sand 1350
g and 360 g of water were prepared in the same manner, and the mortar flow value was measured in the same manner. Since the flow value in this case was 230 mm, a significant difference in properties as a cement dispersant from this powder did not occur.

Example 2 A powder having a particle size of 600 μm or less was produced by the same method and apparatus as in Example 1 except that the aqueous solution used for drying was changed to the following [B]. [B] 74% by mole of methacrylic acid, methoxy poly (n =
23) Ethylene glycol methacrylate 26 mol%
To a high molecular weight compound having a weight average molecular weight of 55,000, and sodium sulfite and triethanolamine in a total amount of about 1
Weight percent, and sodium hydroxide was added as a pH adjuster so as to have a pH of 8.5.
Wt% aqueous solution.

In this example, the processing amount of the material to be ground which could be ground in a pin mill for 10 minutes was 7.3 kg. From the value of the weight of the dried product subjected to the crushing: WD and the weight of the recovered powder having a particle size of 600 μm or less: WP, the yield (=
As a result of calculating (100 × WP / WD), the value was as high as 99%.

Further, 0.54 g of the obtained powder, 900 g of ordinary Portland cement, 1350 g of JIS standard sand, and 360 g of water were put into a Hobart mixer at once, and the mixture was poured into 210 g.
The mortar was adjusted by kneading for 2 seconds. As a result of measuring the flow value of this mortar by the same test method as in Example 1, the flow value was 251 mm. For comparison, 1.08 g of a 50% solids aqueous solution of unpulverized [B],
Normal Portland cement 900g, JIS standard sand 13
The mortar flow value obtained by adjusting 50 g and 360 g of water in the same manner as described above was measured in the same manner. Since the flow value in this case was 252 mm, there was no significant difference in properties as a cement dispersant from the present powder.

Example 3 A powder having a particle diameter of 600 μm or less was produced by the same method and apparatus as in Example 1 except that the aqueous solution used for drying was changed to the following [C]. [C] 50 mol% of maleic anhydride, methoxy poly (n
= 40) Ethylene glycol allyl ether 50 mol%
To a polymer compound having a weight average molecular weight of 43,000 and sodium sulfite and triethanolamine in a total amount of about 1
Weight percent, and sodium hydroxide was added as a pH adjuster so as to have a pH of 8.5.
Wt% aqueous solution.

In this example, the processing amount of the material to be pulverized in a pin mill for 10 minutes was 7.5 kg. From the value of the weight of the dried product subjected to the crushing: WD and the weight of the recovered powder having a particle size of 600 μm or less: WP, the yield (=
As a result of calculating (100 × WP / WD), the value was as high as 99%.

Also, 0.54 g of the obtained powder, 900 g of ordinary Portland cement, 1350 g of JIS standard sand and 360 g of water were put into a Hobart mixer at once, and the mixture was added to
The mortar was adjusted by kneading for 2 seconds. As a result of measuring the flow value of this mortar by the same test method as in Example 1, the flow value was 225 mm. For comparison, 1.08 g of a 50% solids aqueous solution of [C] which has not been powdered, 900 g of ordinary Portland cement, JIS standard sand 135
The flow value of a mortar prepared by adjusting 0 g and 360 g of water in the same manner as described above was measured in the same manner. Since the flow value in this case was 223 mm, there was no significant difference in properties as a cement dispersant between the powder and the present powder.

Example 4 Using the same aqueous solution [A] as in Example 1, drying was carried out in the same manner and under the same conditions as in Example 1, and the dried product taken out from the drying apparatus was powdered by the method described below. Was manufactured.

<Crushing of Dried Product> The dried product was kept at 20 ° C., and then crushed by a crushing granulator (trade name: Power Mill P-3, manufactured by Showa Giken Co., Ltd.) having a screen with 6 mm punch holes.
It was pulverized at a processing speed of 0 kg / H to obtain a crushed product of 6 mm or less.

<Cooling of the crushed material> The crushed material was taken out of the crushing granulator, and cooled to 3 ° C in a constant temperature room, and this state was maintained for about 24 hours.

<Pulverization of Cooled Material> The cooled crushed material was pulverized at room temperature by a vibration mill (trade name: FV-30 type vibration mill, manufactured by Chuo Koki Co., Ltd.) for about 10 minutes.
The pulverized product was passed through a sieve to recover a powder having a particle size of 600 μm or less. In this example, the processing amount of the object to be pulverized in a vibration mill for 10 minutes was 35 kg. The weight of the dried product subjected to the crushing: WD and the collected particle size of 600 μm
m or less: From the value of WP, the yield (= 100 × W
As a result of calculating (P / WD), the value was as high as 97%.

<Properties of Powder> Obtained Powder 0.54
g, 900 g of ordinary Portland cement, 1350 g of JIS standard sand, and 360 g of water were charged all at once into a Hobart mixer and kneaded for 210 seconds to prepare a mortar. As a result of measuring the flow value of this mortar by the same test method as in Example 1, the flow value was 228 mm. For comparison, 1.08 g of a 50% solids aqueous solution of non-pulverized [A], 900 g of ordinary Portland cement, JI
The mortar flow value obtained by preparing 1350 g of S standard sand and 360 g of water in the same manner as described above was measured in the same manner.
Since the flow value in this case was 230 mm, there was no significant difference in properties as a cement dispersant from the present powder.

[Example 5] Using the same aqueous solution [A] as in Example 1, drying was performed by the same method and apparatus as in Example 1, and the dried product taken out from the drying device was subjected to the same method as in Example 4. And after performing the crushing and cooling of the crushed material with the device, the cooled material is used using the same high-speed rotation type pin mill as in Example 1,
The same pulverization treatment as in Example 1 was performed, and the pulverized material taken out of the chamber was passed through a sieve to collect powder having a particle size of 600 μm or less.

In this example, the processing amount of the material to be pulverized by the pin mill for 10 minutes was 11.7 Kg, and showed extremely high pulverization efficiency. The weight of the dried material subjected to the crushing: WD and the particle diameter 600 collected through the above-mentioned treatment
Powder weight of μm or less: From the value of WP, the yield (= 100 ×
As a result of calculating (WP / WD), the value was as high as 99%.

Further, 0.54 g of the obtained powder, 900 g of ordinary Portland cement, 1350 g of JIS standard sand and 360 g of water were put into a Hobart mixer at once, and the mixture was added to
The mortar was adjusted by kneading for 2 seconds. As a result of measuring the flow value of this mortar by the same test method as in Example 1, the flow value was 232 mm. For comparison, 1.08 g of a 50% solids aqueous solution of [A] which is not powdered, 900 g of ordinary Portland cement, JIS standard sand 135
The flow value of a mortar prepared by adjusting 0 g and 360 g of water in the same manner as described above was measured in the same manner. Since the flow value in this case was 230 mm, there was no significant difference in properties as a cement dispersant from the present powder.

[Comparative Example 1] Using the same aqueous solution [A] as in Example 1, drying was performed under the same method and conditions as in Example 1, and the dried product taken out of the drying apparatus was kept at 20 ° C. 1 with a crushing type granulator (trade name: Power Mill P-3 type, manufactured by Showa Giken Co., Ltd.)
Grinding was performed at a processing speed of 00 Kg / H. The powder temperature immediately after milling exceeded 200 ° C. The pulverized product was classified using a vibration sieve, and a powder having a particle size of 600 μm or less was recovered.

0.54 g of the obtained powder, 900 g of ordinary Portland cement, 1350 g of JIS standard sand and water 3
60 g was put into a Hobart mixer all at once and kneaded for 210 seconds to prepare a mortar. As a result of measuring the flow value of this mortar by the same test method as in Example 1, the flow value was 101 mm. For comparison, 1.08 g of a 50% solid content aqueous solution of [A] which is not powdered, 900 g of ordinary Portland cement, 1350 g of JIS standard sand and 360 g of water were prepared in the same manner as described above, and the flow value of the mortar was the same. Was measured. In this case, since the flow value was 230 mm, it was judged that the thermal deterioration of the polymer component was remarkable in this powder, and as a result, the cement dispersing action was significantly reduced.

Comparative Example 2 Using the same aqueous solution [A] as in Example 1, drying was performed in the same manner and under the same conditions as in Example 1, and the dried product taken out of the drying apparatus was kept at 20 ° C. For about 24 hours. Next, the dried product is subjected to the same pulverization treatment as in Example 1 at room temperature (about 20 ± 1 ° C.) using the same high-speed rotary pin mill as in Example 1, and the pulverized product taken out of the chamber is sieved. Through, particle size 600μ
m or less powder was recovered. Weight of dry matter subjected to grinding: WD and weight of recovered powder having a particle size of 600 μm or less:
The yield (= 100 × WP / WD) was calculated from the value of WP to be 69%. In this example, the processing amount of the object to be pulverized in a pin mill for 10 minutes was 3.0K.
g, resulting in low grinding efficiency.

[0038]

According to the production method of the present invention, a powdery polycarboxylic acid system having a high yield, a high efficiency in a short time, and a performance not inferior to that of a liquid can be obtained without a special drying method. A cement dispersant can be obtained.

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Claims (6)

[Claims] 1. A cement dispersant containing a liquid polycarboxylic acid polymer as a main component is dried, and the dried product is crushed mainly by cutting and / or shearing.
A method for producing a powdery cement dispersant, characterized by pulverizing below. 2. The method for producing a powdery cement dispersant according to claim 1, wherein the degree of crystallinity of the polycarboxylic acid-based polymer compound in the crushed material is adjusted to 20% or more, and crushed to 1 mm or less. 3. The temperature of the crushed product is set to 10 ° C. or less and 1 mm
The method for producing a powdery cement dispersant according to claim 1 or 2, wherein the method is pulverized below. 4. A cement dispersant containing a liquid polycarboxylic acid-based polymer compound as a main component is dried, and the crystallinity of the polycarboxylic acid-based polymer compound in the dried product is set to 35% or more, and 1 mm or less. A method for producing a powdery cement dispersant, comprising: 5. The method for producing a powdery cement dispersant according to claim 4, wherein the temperature of the dried product is reduced to 5 ° C. or less and pulverized to 1 mm or less. 6. The method for producing a powdery cement dispersant according to claim 1, wherein the polycarboxylic acid-based polymer compound is a (meth) acrylic acid-based copolymer or a maleic acid-based copolymer.