JP2007238387A - Powdery cement dispersant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means to produce a polycarboxylic acid type cement dispersant which has excellent dispersibility and can be easily pulverized. <P>SOLUTION: The powdery cement dispersant comprises a polycarboxylic acid type copolymer as a main component which has a repeating unit (I) derived from an unsaturated polyalkyleneglycol type monomer, a repeating unit (II) derived from an unsaturated carboxylic acid type monomer, and a repeating unit (III) derived from a branched compound monomer having a branched structure containing three or more polyoxyalkylene chains in the molecule. Alternatively, the powdery cement dispersant contains a polycarboxylic acid type copolymer (A) having a repeating unit (IV) derived from an unsaturated polyalkyleneglycol type monomer and a repeating unit (V) derived from an unsaturated carboxylic acid type monomer and a branched compound (B) having a branched structure containing three or more polyoxyalkylene chains in the molecule. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a powdery cement dispersant, and more particularly to a powdery cement dispersant containing a polycarboxylic acid polymer.

  Concrete has become one of the indispensable materials in modern society, and is widely used in various applications such as buildings, houses, bridges, and tunnels. Typically, concrete is formed by curing a concrete composition that includes cement, water, and aggregate. In addition to these materials, various admixtures are blended in the concrete composition in order to enhance various properties such as fluidity, air entrainment, and freeze-thaw resistance of the cured product.

  As one of admixtures, a cement dispersant is known. In general, the lower the water content, the more improved the durability of the concrete. Therefore, it is preferable that the amount of water in the concrete composition is small. However, if the blending amount of water is too small, the fluidity of the concrete composition cannot be ensured, and workability is deteriorated. The cement dispersant has a function of reducing the amount of water in the concrete composition, and contributes to the solution of this problem.

As one of the cement dispersants, a polycarboxylic acid cement dispersant containing a carboxylic acid or a salt thereof in a repeating unit of a polymer is known. In addition, it is known that the fluidity of cement paste is improved by introducing polyalkylene oxide (PAO;-(AO) _n- ) into a polycarboxylic acid polymer. Compared with conventional naphthalene-based and melamine-based cement dispersants, polycarboxylic acid-based cement dispersants with introduced polyalkylene oxide have cement dispersibility, fluidity in the fresh state of cement composition, fluid retention, Excellent in material separation resistance and curing strength.

  The polycarboxylic acid-based cement dispersant introduced with polyalkylene oxide can be classified into a plurality of types depending on the monomer used as a raw material and the bonding form of the polyalkylene oxide. For example, a polymer (alkenyl PAO ether / acrylic acid structure; in which (meth) acrylic acid or a salt thereof is used as one of raw material monomers and polyalkylene oxide is bonded to the main chain of another raw material monomer by an ether bond; (Wherein COOY represents a carboxyl group or a salt thereof), maleic acid or fumaric acid or a salt thereof is used as one of the raw material monomers, and polyalkylene oxide is present in the main chain of the other raw material monomers. A polymer (alkenyl PAO ether / maleic acid structure; see the following formula (2)), (meth) acrylic acid or a salt thereof used as one of the raw material monomers, and the main chain of other raw material monomers A polymer (poly (meth) acrylic P) in which polyalkylene oxide is bonded with an ester bond O ester / (meth) acrylic acid structure; formula (3) refer to), and the like. In addition, various polymers are classified into acid type, monovalent metal salt type, divalent metal salt type, trivalent metal salt type, etc., depending on whether the carboxylic acid moiety remains carboxylic acid or is a metal salt. being classified.

  Conventionally, for example, Patent Document 1 discloses a monovalent metal salt type polymer of (meth) acrylic PAO ester / (meth) acrylic acid structure and (meth) acrylic PAO ester / alkenyl PAO ether / (meth) acrylic acid structure. ing. For example, Patent Document 2 discloses a monovalent metal salt type polymer of (meth) acrylic PAO ester / (meth) acrylic acid structure and alkenyl PAO ether / acrylic acid structure. Further, for example, Patent Document 3 discloses a divalent metal salt type polymer having a (meth) acrylic PAO ester / (meth) acrylic acid structure and an alkenyl PAO ether / acrylic acid structure. For example, Patent Document 4 discloses a divalent metal salt type polymer having an alkenyl PAO ether / maleic acid structure.

In order to improve the properties as a cement dispersant, a method of adding other components to the polycarboxylic acid polymer has also been proposed. For example, a cement dispersant in which a polycarboxylic acid polymer and PEG are mixed is disclosed (see, for example, Patent Document 5). Further, a cement composition obtained by addition polymerization of an alkylene oxide to a polycarboxylic acid polymer and a polyalkylene polyamine has been disclosed (see, for example, Patent Document 6).
JP 2000-26145 A JP 2002-167255 A JP 2002-167256 A JP-A-9-309756 JP 2000-26146 A JP 2000-109357 A

  The above-described polycarboxylic acid-based cement dispersant is usually used as a liquid product, but considering the transportation cost and the like, the cement dispersant is preferably in a powder form. The cement dispersant is also required to have high dispersion performance. However, the conventional polycarboxylic acid-based cement dispersant in which the polyalkylene oxide moiety is present in the polymer tends to be in the form of wax or elutriation even when moisture is removed, and tends to be difficult to be pulverized.

  Accordingly, an object of the present invention is to provide a means capable of facilitating pulverization while exhibiting excellent dispersion performance in a polycarboxylic acid cement dispersant.

  The present inventors have intensively studied to solve the above problems. As a result, when a branched compound having a branched structure containing three or more polyoxyalkylene chains in the molecule is combined with or mixed with a polycarboxylic acid polymer having a specific structure having a polyalkylene oxide moiety, the dispersion performance is impaired. Thus, it has been found that a polycarboxylic acid polymer-containing solution that has been difficult to be pulverized can be easily pulverized. And based on such knowledge, it came to complete this invention. In addition, although the mechanism by which such an effect as described above is obtained by such a configuration is unknown, the branched compound and the polycarboxylic acid polymer having a specific structure interact with each other, and the molecular weight of the polymer increases in a pseudo manner. The mechanism is estimated. However, this mechanism is merely a guess, and the technical scope of the present invention is not affected at all even if the above-described effects are obtained by other mechanisms.

  Specifically, the first of the present invention is a repeating unit (I) derived from an unsaturated polyalkylene glycol monomer, a repeating unit (II) derived from an unsaturated carboxylic acid monomer, and a polyoxyalkylene. A powdery cement dispersant mainly comprising a polycarboxylic acid copolymer having a repeating unit (III) derived from a branched compound monomer having a branched structure containing three or more chains in the molecule.

  The second of the present invention is a polycarboxylic acid copolymer having a repeating unit (IV) derived from an unsaturated polyalkylene glycol monomer and a repeating unit (V) derived from an unsaturated carboxylic acid monomer. A powdery cement dispersant containing (A) and a branched compound (B) having a branched structure containing three or more polyoxyalkylene chains in the molecule.

  ADVANTAGE OF THE INVENTION According to this invention, the polycarboxylic-acid-type cement dispersing agent which expresses the outstanding dispersibility and can be easily pulverized can be provided.

  Hereinafter, the present invention will be described in detail by dividing it into several embodiments. However, the technical scope of the present invention should be determined based on the description of the claims, and is limited by the following specific modes. Should not be done.

  In the first aspect of the present invention, a repeating unit (I) derived from an unsaturated polyalkylene glycol monomer, a repeating unit (II) derived from an unsaturated carboxylic acid monomer, and a polyoxyalkylene chain are contained in the molecule. A powdery cement dispersant mainly comprising a polycarboxylic acid-based copolymer having a repeating unit (III) derived from a branched compound monomer having a branched structure containing three or more.

(First embodiment)
This embodiment relates to the first aspect of the present invention, and specifically, the repeating unit (I) derived from an unsaturated polyalkylene glycol monomer represented by the following chemical formula 1 (hereinafter referred to as “repeating unit”). (Also referred to as (Ia) ”), a repeating unit (II) derived from an unsaturated carboxylic acid monomer represented by the following chemical formula 2 (hereinafter also referred to as“ repeating unit (II-a) ”), A powdery cement dispersant mainly comprising a polycarboxylic acid copolymer having a repeating unit (III) derived from a branched compound monomer having a branched structure containing three or more polyoxyalkylene chains in the molecule. It is.

In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and AO independently represents an oxy having 2 to 18 carbon atoms. Represents an alkylene group, R ^a represents an alkylene group having 0 to 2 carbon atoms, n represents an average number of added moles of the oxyalkylene group, is 2 to 300, and R ³ and R ⁴ are each independently And represents a hydrogen atom, a methyl group or —COOM ² (except when both R ³ and R ⁴ are —COOM ² ), and R ⁵ represents a hydrogen atom, a methyl group or —CH ₂ COOM ³ . (Wherein R ⁵ is —CH ₂ COOM ³ , R ³ and R ⁴ each independently represents a hydrogen atom or a methyl group), M ¹ , M ² and M ³ are each independently Hydrogen atom, metal source , An ammonium group or an organic amine group.

  In the first aspect of the present invention, the “branched compound monomer” that forms the repeating unit (III) derived from the branched compound monomer is obtained by introducing a polymerizable unsaturated double bond into the above-mentioned predetermined branched compound. Means a monomer.

  In this embodiment, the branched compound is a polyhydric alcohol alkylene oxide adduct having a structure in which an oxyalkylene group is bonded to a polyhydric alcohol residue having an average of 3 or more hydroxyl groups per molecule. In other words, the powdery cement dispersant of the present embodiment has a specific structure of a polycarboxylic acid-based polymer having a polyalkylene oxide moiety and is a predetermined branched compound monomer. The main component is a polycarboxylic acid copolymer in which a polyhydric alcohol alkylene oxide adduct monomer having a structure in which an oxyalkylene group is bonded to a polyhydric alcohol residue having a hydroxyl group is copolymerized. Here, the “polyhydric alcohol alkylene oxide adduct” refers to a group having a structure in which active hydrogen is removed from a hydroxyl group of a polyhydric alcohol having 3 or more hydroxyl groups per molecule on average (hereinafter simply referred to as “polyvalent alcohol”). It means a compound having a structure in which an oxyalkylene group is added to an “alcohol residue”. The “polyhydric alcohol alkylene oxide adduct monomer” means a polyhydric alcohol alkylene oxide adduct having a polymerizable unsaturated double bond. Details of the polyhydric alcohol alkylene oxide adduct and the polyhydric alcohol alkylene oxide adduct monomer will be described later.

  Hereinafter, each of the repeating unit (Ia) represented by the chemical formula 1 and the repeating unit (II-a) represented by the chemical formula 2 will be described in detail, and then “polyhydric alcohol alkylene oxide adduct monomer”. Will be described in detail.

(Repeating unit (Ia) represented by Chemical Formula 1)
In the repeating unit (Ia) represented by Chemical Formula 1, R ¹ is a hydrogen atom or a methyl group. R ² is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. Examples of the hydrocarbon group include an alkyl group, an alkenyl group, an aryl group, and an alkylphenyl group. Examples of such an alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a cyclohexyl group, and a 2-ethylhexyl group. Is mentioned. The “alkenyl group” means a monovalent group represented by the general formula C _n H _{2n-1 in} which one hydrogen atom is removed from any carbon atom of an alkene. Examples of such an alkenyl group include a vinyl group, an allyl group, a propenyl group, and an isopropenyl group. Furthermore, examples of the aryl group include a phenyl group and a naphthyl group. Examples of the alkylphenyl group include a methylphenyl group and an ethylphenyl group. From the viewpoint of fluidity, R ² is preferably a hydrogen atom or a methyl group.

In the repeating unit (Ia) represented by Chemical Formula 1, AO represents an oxyalkylene group having 2 to 18 carbon atoms. Examples of “A” constituting such an oxyalkylene group include an ethylene group, a trimethylene group, a methylethylene group, an ethylethylene group, a phenylethylene group, a tetramethylene group, and a 1,2-dimethylethylene group. . That is, in Chemical Formula 1, “AO” is an oxyalkylene group (for example, oxyethylene group) containing the above functional group. Especially, it is preferable that A is an ethylene group or a methylethylene group from a viewpoint of being excellent in fluidity | liquidity. In some cases, two or more different AO structures may exist in the repeating unit represented by (AO) _n . However, considering the ease of production of the polyoxyalkylene chain and the ease of control of the structure, the repeating structure represented by (AO) _n is preferably a repetition of the same AO structure.

In the repeating unit (Ia) represented by Chemical Formula 1, R ^a represents an alkylene group having 0 to 2 carbon atoms. Note that “R ^a is an alkylene group having 0 carbon atoms” means that there is no site represented by R ^a and ^a structure in which O (AO) _n R ² is directly bonded to a carbon atom constituting the main chain. It means to become. When R ^a has 1 carbon atom, the main chain carbon atom and O (AO) _n R ² are connected by a methylene group. When R ^a has 2 carbon atoms, Has a structure in which the carbon atom of the main chain and O (AO) _n R ² are connected by an ethylene group or a methylmethylene group.

  In the repeating unit (Ia) represented by Chemical Formula 1, n represents the average added mole number of the oxyalkylene group represented by “AO” and is an integer of 2 to 300. From the viewpoint of excellent fluidity and ease of pulverization, n is preferably 10 to 200, more preferably 20 to 150.

  As a monomer which forms the repeating unit (Ia) represented by Chemical Formula 1, for example, vinyl alcohol, allyl alcohol, methallyl alcohol, isoprene alcohol (3-methyl-3-buten-1-ol), An alkylene oxide adduct of an unsaturated alcohol obtained by adding 2 to 300 moles of alkylene oxide to an unsaturated alcohol such as 3-methyl-3-buten-2-ol. Two or more of these may be used in combination.

  Moreover, the monomer which forms the repeating unit (Ia) represented by Chemical Formula 1 may be a commercially available compound, or may be prepared by synthesis by itself. In the synthesis, knowledge already obtained is referred to as appropriate. For example, when alkylene oxide is added to an unsaturated alcohol, vinyl alcohol, allyl alcohol, methallyl alcohol, isoprene alcohol (3-methyl-3-buten-1-ol), 3-methyl-3-butene-2 An alkylene oxide such as ethylene oxide, propylene oxide, or butylene oxide may be added to an unsaturated alcohol such as -ol. Although the temperature conditions at the time of performing an alkylene oxide addition reaction are not specifically limited, Preferably it is 80-155 degreeC, More preferably, it is 90-150 degreeC.

(Repeating unit (II-a) represented by Chemical Formula 2)
In the repeating unit (II-a) represented by Chemical Formula 2, R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or —COOM ² . However, the case where both R ³ and R ⁴ are —COOM ² is excluded. R ⁵ represents a hydrogen atom, a methyl group, or —CH ₂ COOM ³ . However, when R ⁵ is —CH ₂ COOM ³ , R ³ and R ⁴ each independently represent a hydrogen atom or a methyl group and do not represent —COOM ² . Furthermore, in the repeating unit represented by Chemical Formula 2, M ¹ , M ² and M ³ each independently represent a hydrogen atom, a metal atom, an ammonium group or an organic amine group. When M ¹ , M ² or M ³ is a metal atom, the metal atom may be any of monovalent, divalent, and trivalent, specifically, an alkali such as lithium, sodium, or potassium Preferred are monovalent metal atoms such as metal atoms; divalent metal atoms such as alkaline earth metal atoms such as calcium and magnesium; and trivalent metal atoms such as aluminum and iron. Among these, from the viewpoint of improving the ease of pulverization, M ¹ , M ² and M ³ are preferably a monovalent metal atom or a divalent metal atom. The ammonium group is a functional group represented by “—NH ₃ ⁺ ”. The organic amine group includes, for example, alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine; alkylamines such as monoethylamine, diethylamine, and triethylamine; residues derived from organic amines such as polyamines such as ethylenediamine and triethylenediamine. Is mentioned.

When R ³ and R ⁴ are hydrogen atoms, the repeating unit (II-a) represented by Chemical Formula 2 is an acrylic acid (when R ⁵ is a hydrogen atom) or methacrylic acid (R ⁵ is a methyl group). In the case). In addition, when R ⁴ is a carboxyl group and R ⁵ is a hydrogen atom, the repeating unit represented by Chemical Formula 2 is a site derived from maleic acid or fumaric acid. Furthermore, when R ⁴ is a carboxyl group and R ⁵ is a CH ₂ COOH group, the repeating unit represented by Chemical Formula 2 is a site derived from itaconic acid.

  Examples of the monomer that forms the repeating unit (II-a) represented by Chemical Formula 2 include acrylic acid, methacrylic acid, sodium acrylate, sodium methacrylate, ammonium acrylate, and ammonium methacrylate. Two or more of these may be used in combination. As these monomers, commercially available compounds may be used, or they may be prepared by synthesis themselves.

(Repeating unit (III) derived from a branched compound monomer having a branched structure containing three or more polyoxyalkylene chains in the molecule)
In addition to the repeating unit (Ia) represented by the chemical formula 1 and the repeating unit (II-a) represented by the chemical formula 2, the powdered cement dispersant of the present embodiment has a polyoxyalkylene chain as a molecule. It further has a repeating unit (III) derived from a branched compound monomer having a branched structure containing three or more therein (specifically, a repeating unit (III) derived from a polyhydric alcohol alkylene oxide adduct monomer). In this embodiment, the said repeating unit (III) is a bivalent repeating unit produced by the cutting | disconnection of one coupling | bonding of the polymerizable unsaturated double bond which a polyhydric alcohol alkylene oxide adduct monomer has.

  The “polyhydric alcohol” constituting the “polyhydric alcohol residue” in the polyhydric alcohol alkylene oxide adduct means a compound having an average of 3 or more hydroxyl groups per molecule, and its specific form is particularly There is no limit. In a preferred form, the polyhydric alcohol is a compound consisting of three atoms of carbon, hydrogen and oxygen.

  The average value of the number of hydroxyl groups of one molecule of polyhydric alcohol is not particularly limited, but is preferably 3 to 300, more preferably 4 to 100, still more preferably 5 to 50, Preferably 6 to 25. When the average value of the number of hydroxyl groups possessed by one molecule of the polyhydric alcohol is within such a range, the polyhydric alcohol alkylene oxide monomer functions are sufficiently exhibited and the polymerizability is also excellent.

  Preferred specific examples of the polyhydric alcohol include, for example, polyglycidol, glycerin, polyglycerin, trimethylolethane, trimethylolpropane, 1,3,5-pentatriol, erythritol, pentaerythritol, dipentaerythritol, sorbitol, sorbitan, Examples include sorbitol glycerin condensate, adonitol, arabitol, xylitol, and mannitol. Also, sugars of hexoses such as glucose, fructose, mannose, indose, sorbose, growth, talose, tagatose, galactose, allose, psicose, altrose; saccharides of pentoses such as arabinose, ribulose, ribose, xylose, xylulose, lyxose Sugars of tetroses such as threose, erythrulose, erythrose; other sugars such as rhamnose, cellobiose, maltose, isomaltose, trehalose, sucrose, raffinose, gentianose, melezitose; these sugar alcohols, sugar acids (sugars; glucose, sugars Alcohol; glucite, sugar acid; gluconic acid) may also be preferably used. Furthermore, derivatives of these compounds such as partially etherified products and partially esterified products can also be preferably used. One of these polyhydric alcohols may be used alone, or two or more thereof may be used in combination. Among them, in the present invention, it is more preferable to use a polyhydric alcohol (for example, saccharide) having a structure in which a hydroxyl group is bonded to each of two adjacent carbon atoms, and it is particularly preferable to use sorbitol or polyglycerin. Preferably, sorbitol is most preferably used.

  From the viewpoint of not inhibiting the performance as a cement dispersant, the content of the carboxyl group (including the salt form) contained in the polyhydric alcohol alkylene oxide adduct is 1 mol of the oxyalkylene group contained in the adduct. The amount is preferably 0.02 mol or less, more preferably 0.01 mol or less, still more preferably 0.005 mol or less, and most preferably 0 mol.

  As described above, the “polyhydric alcohol alkylene oxide adduct monomer” is a polyhydric alcohol alkylene oxide adduct having a polymerizable unsaturated double bond. In other words, the “polyhydric alcohol alkylene oxide adduct monomer” is an unsaturated monomer having a structure in which an oxyalkylene group is bonded to a polyhydric alcohol residue.

  Examples of a method for producing such a polyhydric alcohol alkylene oxide adduct monomer include (1) a method of introducing an unsaturated group into a compound obtained by adding an alkylene oxide to a polyhydric alcohol, and (2) an unsaturated alcohol. Examples thereof include a method in which 1 mol or more of glycidol is added to 1 mol of an unsaturated alcohol polyalkylene glycol adduct to generate 2 or more hydroxyl groups in one molecule and then an alkylene oxide is added.

  In the above method (1), as a method for introducing an unsaturated group, a hydroxyl group of a compound obtained by adding an alkylene oxide to a polyhydric alcohol has a (meth) acrylic acid such as (meth) acrylic acid or methyl (meth) acrylate. A method of introducing an unsaturated group by esterification or transesterification with an unsaturated compound such as an acid alkyl ester, a hydroxyl group of a compound obtained by adding an alkylene oxide to a polyhydric alcohol, glycidyl (meth) acrylate or (meth) allyl A method of introducing an unsaturated group by reacting an epoxy compound having 2 to 5 carbon atoms such as glycidyl ether, or an etherification with an alkenyl halide having 2 to 5 carbon atoms such as (meth) allyl chloride. A method of introducing a group or the like is preferably used. As unsaturated compounds for introducing unsaturated groups, unsaturated carboxylic acids such as (meth) acrylic acid, maleic acid, fumaric acid and citraconic acid; unsaturated compounds such as (meth) acrylic anhydride and maleic anhydride Carboxylic anhydride; unsaturated carboxylic acid halide such as (meth) acrylic acid chloride; (meth) acrylic acid alkyl ester having 1 to 30 carbon atoms, maleic acid monoester having 1 to 30 carbon atoms, 1 to 30 carbon atoms Preferably used are unsaturated carboxylic acid esters such as maleic acid diesters; epoxy compounds such as glycidyl (meth) acrylate and (meth) allyl glycidyl ether. These compounds may be used independently and may use 2 or more types together. In particular, the alkenyl compound-based unsaturated group is preferably an unsaturated group having 4 or more carbon atoms, and more preferably an unsaturated group having 5 or more carbon atoms. Moreover, a methallyl group and an isoprenyl group (3-methyl-3-butenyl group) are more preferable than an allyl group. Furthermore, a (meth) acryloyl group can also be preferably used.

  In the above method (2), examples of the unsaturated alcohol include vinyl alcohol, (meth) allyl alcohol, 3-buten-1-ol, isoprene alcohol (3-methyl-3-buten-1-ol), and 3-methyl. -3-buten-2-ol, 3-methyl-2-buten-1-ol, 2-methyl-3-buten-2-ol, 2-methyl-2-buten-1-ol, 2-methyl-3 -Buten-1-ol etc. are preferably used. In addition, as the unsaturated alcohol polyalkylene glycol adduct, a compound having a structure in which a polyalkylene glycol chain is added to the unsaturated alcohol as described above may be used.

  The polyhydric alcohol alkylene oxide adduct monomer has a group formed by one oxyalkylene group or a group formed by adding two or more oxyalkylene groups (polyalkylene glycol chain). . In the group formed by adding two or more oxyalkylene groups, the type of the oxyalkylene group forming the group may be only one type or two or more types. When formed with two or more oxyalkylene groups, the addition form of the two or more oxyalkylene groups may be any of random addition, block addition, and alternate addition. In addition, when two or more groups formed with the said oxyalkylene group exist in one molecule, these may be the same and may differ.

  Examples of the oxyalkylene group include ethylene oxide (EO), propylene oxide (PO), isobutylene oxide, 1-butene oxide, 2-butene oxide, trimethylethylene oxide, tetramethylene oxide, tetramethylethylene oxide, butadiene monooxide, and octylene. Examples include groups derived from compounds such as oxide, styrene oxide, and 1,1-diphenylethylene oxide.

The group formed by the oxyalkylene group is preferably mainly composed of an oxyethylene group (—O—CH ₂ —CH ₂ —). In this case, “mainly composed of oxyethylene groups” means that when two or more oxyalkylene groups are present in the monomer, the oxyethylene groups occupy most of the total number of oxyalkylene groups present. It means that. As a result, the hydrophilicity of the polycarboxylic acid copolymer obtained by copolymerization of the polyhydric alcohol alkylene oxide adduct monomer is improved, and the effects thereof are sufficiently exhibited.

  In the above oxyalkylene group, when “mainly composed of oxyethylene groups” is represented by mol% of oxyethylene groups in 100 mol% of all oxyalkylene groups, it is preferably 50 to 100 mol%. When the content of the oxyethylene group is less than 50 mol%, the hydrophilicity of the group formed from the oxyalkylene group may be lowered. More preferably, it is 60 mol% or more, more preferably 70 mol% or more, particularly preferably 80 mol% or more, and most preferably 90 mol% or more.

  The average addition mole number of the oxyalkylene group in the polyhydric alcohol alkylene oxide adduct monomer is preferably more than 0 and 300 or less with respect to 1 mole of the hydroxyl group (—OH group). When it exceeds 300, there exists a possibility that the polymerizability of the said monomer may fall. The average added mole number is more preferably 1 or more, still more preferably 2 or more, particularly preferably 6 or more, and most preferably 12 or more. More preferably, it is 270 or less, More preferably, it is 250 or less, Especially preferably, it is 220 or less, Most preferably, it is 200 or less. When the average addition mole number of the oxyalkylene group in the polyhydric alcohol alkylene oxide adduct monomer is out of such a range, the action of the polycarboxylic acid copolymer having excellent fluidity such as a cement composition There is a possibility that the effect is not sufficiently exhibited. The "average number of moles of oxyalkylene group added in the polyhydric alcohol alkylene oxide adduct monomer" means that 1 mol of the group formed by the oxyalkylene group possessed by the polyhydric alcohol alkylene oxide adduct monomer. The average value of the number of moles of the oxyalkylene group added, or the oxyalkylene group added to 1 mol of the hydroxyl group of the polyhydric alcohol that will form the polyhydric alcohol alkylene oxide adduct monomer Means the average number of moles.

  In the polyhydric alcohol alkylene oxide adduct monomer, it is preferable that at least one terminal of the oxyalkylene group having a structure bonded to a polyhydric alcohol residue is a hydroxyl group. More preferably, all of the terminals of the oxyalkylene group are hydroxyl groups. This is because when the terminal of the oxyalkylene group is an alkyl group, the polycarboxylic acid copolymer obtained by copolymerization with a polyhydric alcohol alkylene oxide adduct monomer is used as a cement additive. This is because there is a risk of decrease.

  The weight average molecular weight of the polyhydric alcohol alkylene oxide adduct monomer is not particularly limited, but is preferably 500 to 500,000, more preferably 1000 or more, further preferably 5000 or more, and particularly preferably 8000 or more. Yes, most preferably 10,000 or more. Further, it is more preferably 300000 or less, further preferably 200000 or less, particularly preferably 100000 or less, and particularly preferably 80000 or less. In addition, as a value of the weight average molecular weight of a polyhydric alcohol alkylene oxide adduct monomer, the value measured by GPC on the following measurement conditions shall be employ | adopted.

  The polycarboxylic acid copolymer constituting the powdery cement dispersant of the present embodiment includes a repeating unit (Ia) represented by Chemical Formula 1, a repeating unit (II-a) represented by Chemical Formula 2, and The repeating unit (III) derived from the predetermined branched compound is contained as an essential component, but other repeating units may be contained. Examples of monomers that form other repeating units include 2- (meth) acrylamido-2-methylpropanesulfonic acid, 2-hydroxy-3-allyloxysulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meta ) Unsaturated sulfonic acids having a sulfonic acid group such as acrylate and styrene sulfonic acid; Unsaturated amides such as (meth) acrylamide and (meth) acrylalkylamide; Vinyl esters such as vinyl acetate and vinyl propionate; Styrene and bromo Examples thereof include styrenes such as styrene; monovalent metal salts, divalent metal salts, ammonium salts, and organic ammonium salts. Each of these repeating units may be present by random polymerization, block polymerization, alternating polymerization, or the like.

  However, in order to obtain a cement dispersant that exhibits excellent dispersion performance and can be easily pulverized during production, the three essential repeating units described above are the main components of the polycarboxylic acid copolymer. A repeating unit is preferred. Specifically, the three essential repeating units described above are preferably included in an amount of 80 to 100%, more preferably 90 to 100%, based on the total number of repeating units of the polycarboxylic acid copolymer.

  In the polycarboxylic acid copolymer that is the main component of the powdery cement dispersant of the present embodiment, the repeating unit (Ia) represented by Chemical Formula 1 and the repeating unit (II-a) represented by Chemical Formula 2 The ratio of the content of the repeating unit (III) derived from the predetermined branched compound is not particularly limited and can be appropriately determined in consideration of the desired dispersion performance. Preferably, the total content of these repeating units is 100. It is preferable that (Ia) / (II-a) / (III) = 40 to 90/5 to 30/5 to 50 mass% with respect to mass%, and (Ia) / (II- It is more preferable that a) / (III) = 50 to 90/5 to 30/5 to 40% by mass, and (Ia) / (II-a) / (III) = 60 to 80/10 to 20 More preferably, it is / 10-30 mass%. It is preferable that the content of each component in the polycarboxylic acid copolymer is a value within such a range from the viewpoint of excellent dispersion performance. In addition, as a value of content of these repeating units, the value measured by methods, such as NMR and an acid value measurement, shall be employ | adopted.

  From the viewpoint of excellent dispersibility, the weight average molecular weight of the polycarboxylic acid copolymer that is the main component of the powdery cement dispersant of the present embodiment is preferably 1,000 to 500,000 in terms of polyethylene glycol. Preferably it is 5000-100000. In addition, as a value of the said weight average molecular weight, the method described in the Example mentioned later is used.

  The average particle diameter of the powdery cement dispersant of this embodiment is preferably 1 to 500 μm, more preferably 10 to 100 μm. If the average particle size is less than 1 μm, the powdered cement dispersant may be easily aggregated, and if it exceeds 500 μm, the solubility in water may be reduced, and the dispersibility in cement may be reduced.

  The method for producing the powdery cement dispersant of the present embodiment is not particularly limited, and conventionally known knowledge relating to the production of the polymer can be appropriately referred to. For example, the repeating unit (Ia) represented by Chemical Formula 1 and A copolymer obtained by copolymerizing a monomer that forms each of the repeating units (II-a) represented by Chemical Formula 2 and a polyhydric alcohol alkylene oxide adduct monomer is dried. A powdered cement dispersant can be produced by pulverization. You may synthesize | combine based on the newly acquired knowledge.

  In order to obtain such a copolymer, the above-mentioned monomers may be mixed at a desired content ratio and polymerized using a polymerization initiator. The polymerization can be performed by a method such as polymerization in a solvent or bulk polymerization. Polymerization in a solvent can be carried out either batchwise or continuously. The solvent used here is water; lower alcohols such as methyl alcohol, ethyl alcohol, 2-propanol; benzene, toluene, xylene, cyclohexane, Examples include aromatic or aliphatic hydrocarbons such as n-hexane; ester compounds such as ethyl acetate; ketone compounds such as acetone and methyl ethyl ketone. In consideration of the solubility of the raw material monomer and the resulting polycarboxylic acid copolymer, and convenience during use of the polycarboxylic acid copolymer, water, methyl alcohol, ethyl alcohol, 2-propanol and the like are solvents. It is particularly effective when used as.

  When polymerization is performed in an aqueous medium, a water-soluble polymerization initiator such as ammonium or alkali metal persulfate or hydrogen peroxide is used as a polymerization initiator. In this case, an accelerator such as sodium bisulfite, Mole salt, ascorbic acid (salt), Rongalite and the like can be used in combination. For polymerization using a lower alcohol, aromatic hydrocarbon, aliphatic hydrocarbon, ester compound or ketone compound as a solvent, a peroxide such as benzoyl peroxide or lauroyl peroxide; a hydroperoxide such as cumene hydroperoxide; An azo compound such as azobisisobutyronitrile is used as a polymerization initiator. In this case, an accelerator such as an amine compound can be used in combination. Furthermore, when a water-lower alcohol mixed solvent is used, it can be appropriately selected from the above-mentioned various polymerization initiators or combinations of polymerization initiators and accelerators. The polymerization temperature can be appropriately determined depending on the solvent used and the polymerization initiator, but is usually performed within the range of 0 to 120 ° C.

  Bulk polymerization uses, for example, a peroxide such as benzoyl peroxide or lauroyl peroxide as a polymerization initiator; a hydroperoxide such as cumene hydroperoxide; an azo compound such as azobisisobutyronitrile, and the like. Within the temperature range of.

  Moreover, hypophosphorous acid (salt) and a thiol chain transfer agent can be used in combination for the purpose of adjusting the molecular weight of the resulting polycarboxylic acid copolymer. Examples of the thiol chain transfer agent used in this case include mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycolate, and 3-mercaptopropionic acid. Examples include octyl, octyl mercaptan, dodecyl mercaptan and the like, and one or more of these can be used. Furthermore, in order to adjust the molecular weight of the polycarboxylic acid copolymer, it is also effective to use a monomer having a high chain transfer property such as (meth) allylsulfonic acid (salt) as a monomer.

  There is no particular limitation on the drying means for drying the copolymer to form powder. A drying means may be selected according to the properties of the copolymer. As such drying means, for example, a solution containing a copolymer is dried and pulverized, salted out, coagulation sedimentation, freeze drying, coagulation pulverization drying, spray dryer method, drum dryer method, belt dryer. Law. Among these, from the viewpoint of preventing thermal deterioration of the copolymer, a drying means (for example, freeze-drying method) in which the copolymer is less heated can be preferably used. According to the lyophilization method, for example, a solution containing a copolymer is rapidly cooled using liquid nitrogen or the like and frozen, and then the frozen copolymer solution is dried under reduced pressure using a freeze dryer. Thereby, for example, a powder having a particle size of about 40 nm to 500 μm is obtained. Also, according to the spray dryer method, the copolymer solution is atomized using a spray dryer and dried in the air by mixing with hot air. Thereby, for example, a powder having an average particle diameter of 100 μm or less is obtained. Further, according to the drum dryer method or the belt dryer method, the copolymer solution is dried to a film thickness of 100 μm or less using a drum dryer or a belt dryer, and this is pulverized and classified. Thereby, for example, a powder having an average particle size of 300 μm or less is obtained. The particle size of the powder obtained by pulverization by drying may be further adjusted by any pulverization / classification means to obtain a powdery cement dispersant having a desired particle size.

(Second Embodiment)
This embodiment relates to the first aspect of the present invention, and specifically, a repeating unit (I) derived from an unsaturated polyalkylene glycol monomer represented by the following chemical formula 3 (hereinafter referred to as “repeating unit”). (Also referred to as (Ib) "), repeating unit (II) derived from an unsaturated carboxylic acid monomer represented by the following chemical formula 2 (hereinafter also referred to as" repeating unit (II-b) "), A powdery cement dispersant mainly comprising a polycarboxylic acid copolymer having a repeating unit (III) derived from a branched compound monomer having a branched structure containing three or more polyoxyalkylene chains in the molecule. It is.

In the formula, R ⁶ represents a hydrogen atom or a methyl group, R ⁷ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and BO is independently an oxy having 2 to 18 carbon atoms. Represents an alkylene group, p represents an average addition mole number of the oxyalkylene group, is 2 to 300, R ⁸ represents a hydrogen atom or a methyl group, and R ⁹ represents a hydrogen atom, a methyl group or —CH _2. COOM ⁵ is represented, and M ⁴ and M ⁵ each independently represent a hydrogen atom, a metal atom, an ammonium group or an organic amine group.

  Also in this embodiment, the branched compound is a polyhydric alcohol alkylene oxide adduct having a structure in which an oxyalkylene group is bonded to a polyhydric alcohol residue having an average of 3 or more hydroxyl groups per molecule. In other words, the powdery cement dispersant of the present embodiment has a polyalkylene oxide moiety, but the polycarboxylic acid polymer having a structure different from that of the first embodiment is a predetermined branched compound monomer. A polycarboxylic acid copolymer having a structure in which a polyhydric alcohol alkylene oxide adduct monomer having a structure in which an oxyalkylene group is bonded to a polyhydric alcohol residue having 3 or more hydroxyl groups per molecule is copolymerized Main unit is coalescence. In other words, the polycarboxylic acid copolymer that is the main component of this embodiment is the same as that of the first embodiment in that it has a repeating unit (III) derived from a predetermined branched compound, Unlike the first embodiment, the structure of the other repeating unit of the polycarboxylic acid copolymer that is the main component is different from that of the first embodiment, and the polymer is represented by the repeating unit (Ib) represented by the chemical formula 3 and the chemical formula 4. Repeat unit (II-b) is included. Here, in the present embodiment, the specific form of the “repeating unit (III) derived from a branched compound monomer having a branched structure containing three or more polyoxyalkylene chains in the molecule” is described in the first embodiment. Since it is the same as that of a form, detailed description is abbreviate | omitted here.

  Hereinafter, the repeating unit (Ib) represented by Chemical Formula 3 and the repeating unit (II-b) represented by Chemical Formula 4 will be described in detail.

(Repeating unit (Ib) represented by Chemical Formula 3)
In the repeating unit (I-b) represented by the Chemical Formula 3, specific form of the R ⁶ and R ^7, R ¹ in the repeating unit (I-a) represented by the Chemical Formula 1 in the first embodiment described above And R ² is the same. Therefore, detailed description is omitted here.

  In the repeating unit (Ib) represented by Chemical Formula 3, the specific form of B is the same as A in the repeating unit (Ia) represented by Chemical Formula 1 in the first embodiment. Therefore, detailed description is omitted here.

  In the repeating unit (Ib) represented by Chemical Formula 3, p represents the average added mole number of the oxyalkylene group represented by “BO” and is an integer of 2 to 300. From the viewpoint of excellent fluidity and ease of pulverization, p is preferably 10 to 200, more preferably 20 to 150.

  Examples of the monomer that forms the repeating unit (Ib) represented by Chemical Formula 3 include polyethylene glycol mono (meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate, ethoxypolyethylene glycol mono (meth) acrylate, and methoxypolypropylene. “Polyalkylene glycol and (meth) acrylic” such as glycol mono (meth) acrylate, methoxypolyethylene glycol polypropylene glycol mono (meth) acrylate, methoxypolybutylene glycol mono (meth) acrylate, methoxypolyethylene glycol polybutylene glycol mono (meth) acrylate, etc. And an esterified product with an acid ”. Two or more of these may be used in combination.

  As the monomer that forms the repeating unit (Ib) represented by Chemical Formula 3, a commercially available compound may be used, or it may be prepared by synthesis by itself. In the synthesis, knowledge already obtained is referred to as appropriate. As a method for producing the monomer, for example, an esterified product of polyalkylene glycol and (meth) acrylic acid is (meth) acrylic acid methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, ) Synthesis is possible by transesterification of alkyl acrylate and polyalkylene glycol. In addition, a method of esterifying polyalkylene glycol and (meth) acrylic acid may be used.

(Repeating unit (II-b) represented by Chemical Formula 4)
In the repeating unit (II-b) represented by Chemical Formula 4, R ⁸ represents a hydrogen atom or a methyl group. R ⁹ represents a hydrogen atom, a methyl group or —CH ₂ COOM ⁵ . Here, R ⁸ and R ⁹ may be the same or different. Furthermore, M ⁴ and M ⁵ each independently represent a hydrogen atom, a metal atom, an ammonium group, or an organic amine group, and the specific form thereof is represented by the chemical formula 1 in the first embodiment. The same as M ^{1 to} M ³ in the unit (Ia) or the repeating unit (II-a) represented by Chemical Formula 2. Therefore, detailed description is omitted here.

  Examples of the monomer that forms the repeating unit (II-b) represented by Chemical Formula 4 include acrylic acid and methacrylic acid. These may be used alone or in combination.

  The polycarboxylic acid copolymer constituting the powdered cement dispersant of the present embodiment includes a repeating unit (Ib) represented by Chemical Formula 3, a repeating unit (II-b) represented by Chemical Formula 4, and Although the repeating unit (III) derived from the polyhydric alcohol alkylene oxide adduct monomer is contained as an essential component, other repeating units may be contained. Here, the specific form of the monomer forming the other repeating unit is “other monomer” in the polycarboxylic acid copolymer which is the main component of the cement dispersant of the first embodiment. It is the same. Therefore, detailed description is omitted here.

  The repeating units (Ia), (II-a), (III) and other repeating units, or the repeating units (Ib), (II-b), (III) and other repeating units are: It may be copolymerized in a block shape or may be copolymerized in a random shape.

  Here, in order to obtain a cement dispersant that exhibits excellent dispersion performance and can be easily pulverized during production, the three essential repeating units described above are the main components of the polycarboxylic acid copolymer. It is preferable that it is a repeating unit. Specifically, the three essential repeating units described above are preferably included in an amount of 80 to 100%, more preferably 90 to 100%, based on the total number of repeating units of the polycarboxylic acid copolymer.

  In the polycarboxylic acid copolymer that is the main component of the powdery cement dispersant of the present embodiment, the repeating unit (Ib) represented by Chemical Formula 3 and the repeating unit (II-b) represented by Chemical Formula 4 And the ratio of the content of the repeating unit (III) derived from the polyhydric alcohol alkylene oxide adduct monomer is not particularly limited and can be appropriately determined in consideration of the desired dispersion performance. The same as in the case of the repeating unit (Ia), the repeating unit (II-a) and the repeating unit (III) in the first embodiment. Therefore, detailed description is omitted here.

  About the preferable form of the weight average molecular weight and average particle diameter of the powdery cement dispersant of this embodiment, it is the same as that of the preferable form in said 1st Embodiment. Therefore, detailed description is omitted here.

  The method for producing the powdery cement dispersant of the present embodiment is not particularly limited, and the monomer that forms the repeating unit represented by Chemical Formula 1 and Chemical Formula 2 is selected from the repeating unit represented by Chemical Formula 3 and Chemical Formula 4. The method described in the column of the first embodiment can be similarly used except that the monomer to be formed is used. Therefore, detailed description is omitted here.

  The first powdered cement dispersant of the present invention has been specifically described above by taking the first embodiment and the second embodiment as examples, but the technical scope of the first powdered cement dispersant of the present invention. Should not be limited only to this embodiment. For example, in the above-described embodiment, instead of the repeating unit (Ia) represented by Chemical Formula 1 or the repeating unit (Ib) represented by Chemical Formula 3, an unsaturated polyalkylene glycol-based monomer other than these In place of the form containing the repeating unit (I) derived from the body, the repeating unit (II-a) represented by the chemical formula 2 or the repeating unit (II-b) represented by the chemical formula 4, The form containing the repeating unit (II) derived from the carboxylic acid monomer can also be included in the technical scope of the first powdered cement dispersant of the present invention. The specific forms of the repeating unit (I) and the repeating unit (II) other than those detailed in the first embodiment and the second embodiment are not particularly limited, and conventionally known knowledge is appropriately referred to. Thus, it can be suitably used in the first aspect of the present invention.

  The second of the present invention is a polycarboxylic acid copolymer (A) having a repeating unit (IV) derived from an unsaturated polyalkylene glycol monomer and a repeating unit (V) derived from an unsaturated carboxylic acid monomer. And a branched compound (B) having a branched structure containing three or more polyoxyalkylene chains in the molecule.

(Third embodiment)
This embodiment relates to the second of the present invention, and specifically, a repeating unit (IV) derived from an unsaturated polyalkylene glycol monomer represented by the following chemical formula 5 or 6: Hereinafter, the repeating unit (IV) derived from the left unsaturated polyalkylene glycol monomer in Formula 5 is also referred to as “IV-a”, and the repeating unit derived from the left unsaturated polyalkylene glycol monomer in Formula 6 (IV) is also referred to as “IV-b”) and a repeating unit derived from an unsaturated carboxylic acid monomer (V) (hereinafter, a repeating unit derived from an unsaturated carboxylic acid monomer on the right side in Formula 5 (V ) Is also referred to as “Va”, and the repeating unit (V) derived from the unsaturated carboxylic acid monomer on the right side in Formula 6 is also referred to as “Vb”) Co polymer (A), branched compound having a branched structure containing 3 or more in the molecule a polyoxyalkylene chain (B), and including a powdery cement dispersant. In the following description, a polycarboxylic acid copolymer having a repeating unit represented by Chemical Formula 5 is also referred to as “copolymer (Aa)”, and a polycarboxylic acid-based copolymer represented by Chemical Formula 6 is used. The carboxylic acid copolymer is also referred to as “copolymer (Ab)”.

In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and AO independently represents an oxy having 2 to 18 carbon atoms. Represents an alkylene group, R ^a represents an alkylene group having 0 to 2 carbon atoms, n represents an average number of added moles of the oxyalkylene group, is 2 to 300, and R ³ and R ⁴ are each independently And represents a hydrogen atom, a methyl group or —COOM ² (except when both R ³ and R ⁴ are —COOM ² ), and R ⁵ represents a hydrogen atom, a methyl group or —CH ₂ COOM ³ . (Wherein R ⁵ is —CH ₂ COOM ³ , R ³ and R ⁴ each independently represents a hydrogen atom or a methyl group), M ¹ , M ² and M ³ are each independently Hydrogen atom, metal source , An ammonium group or an organic amine group,

In the formula, R ⁶ represents a hydrogen atom or a methyl group, R ⁷ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and BO is independently an oxy having 2 to 18 carbon atoms. Represents an alkylene group, p represents an average addition mole number of the oxyalkylene group, is 2 to 300, R ⁸ represents a hydrogen atom or a methyl group, and R ⁹ represents a hydrogen atom, a methyl group or —CH _2. COOM ⁵ is represented, and M ⁴ and M ⁵ each independently represent a hydrogen atom, a metal atom, an ammonium group or an organic amine group.

  That is, the powdery cement dispersant of this embodiment includes a polycarboxylic acid polymer having a specific structure having a polyalkylene oxide moiety and a branched compound having a branched structure containing three or more polyoxyalkylene chains in the molecule (specifically Includes a polyhydric alcohol alkylene oxide adduct having a structure in which an oxyalkylene group is bonded to a polyhydric alcohol residue having an average of 3 or more hydroxyl groups per molecule (for example, a mixture thereof) ). Here, the powdery cement dispersant of the first and second embodiments is a polycarboxylic acid copolymer obtained by copolymerizing a predetermined branched compound monomer in a polycarboxylic acid polymer having a predetermined structure. Is the main component. On the other hand, the powdery cement dispersant of the present embodiment includes (mixed) the predetermined polycarboxylic acid polymer and the predetermined branched compound without a covalent bond. Different from the first and second embodiments.

  Hereinafter, the polycarboxylic acid copolymer (A) and the branched compound (B) having a branched structure containing three or more polyoxyalkylene chains in the molecule will be described in detail.

(Polycarboxylic acid copolymer (A))
The polycarboxylic acid copolymer (A) used in the powdery cement dispersant of this embodiment has a repeating unit represented by the above chemical formula 5 or the above chemical formula 6.

  First, the polycarboxylic acid copolymer (Aa) having a repeating unit represented by Chemical Formula 5 (that is, a repeating unit (IV-a) and a repeating unit (Va)) will be described.

  The repeating unit (IV-a) on the left side in Chemical Formula 5 is the same as the repeating unit (Ia) represented by Chemical Formula 1 in the first embodiment. Moreover, the repeating unit (Va) on the right side in Chemical Formula 5 is the same as the repeating unit (II-a) represented by Chemical Formula 2 in the first embodiment. Therefore, detailed description is omitted here.

  The ratio of the content of (IV-a) and (Va) in Chemical Formula 5 is not particularly limited. However, in order to express the adsorption performance by the carboxyl group and the dispersion performance by the polyoxyalkylene chain in a balanced manner, the total number of repeating units (IV-a): the total number of repeating units (Va) is preferably 1: It is 0.1 to 1:50, More preferably, it is 1: 0.5 to 1:20, More preferably, it is 1: 1 to 1: 4.

  In the polycarboxylic acid copolymer (Aa) having a repeating unit represented by the chemical formula 5, in addition to the repeating unit (IV-a) and the repeating unit (Va), other repeating units. May be included. Here, the specific form of the monomer forming the other repeating unit is “other monomer” in the polycarboxylic acid copolymer which is the main component of the cement dispersant of the first embodiment. It is the same. Therefore, detailed description is omitted here.

  In addition, in the polycarboxylic acid-type copolymer (Aa) which has a repeating unit represented by Chemical formula 5, a repeating unit (IV-a), a repeating unit (Va), and another repeating unit are block shape. The copolymer may be copolymerized in random, or may be copolymerized randomly.

  Here, in order to obtain a cement dispersant that exhibits excellent dispersion performance and can be easily pulverized during production, two repeating units represented by Formula 5 (that is, repeating units (IV-a ) And the repeating unit (Va)) are preferably main repeating units in the polycarboxylic acid copolymer (Aa) having the repeating unit represented by the chemical formula 5. Specifically, the two repeating units represented by Chemical Formula 5 ((IV-a) and (Va)) are preferably based on the total number of all repeating units of the copolymer (Aa), 60 to 95% is contained, more preferably 70 to 90%.

  The weight average molecular weight of the polycarboxylic acid copolymer (Aa) having a repeating unit represented by Chemical Formula 5 is preferably 1000 to 500,000 in terms of polyethylene glycol, from the viewpoint of excellent fluidity. More preferably, it is 5000-100000. In addition, the method described in the Example mentioned later is used for the measurement of the value of the said weight average molecular weight.

  Subsequently, the polycarboxylic acid copolymer (Ab) having a repeating unit represented by Chemical Formula 6 will be described.

  The left repeating unit (IV-b) in Chemical Formula 6 is the same as the repeating unit (Ib) represented by Chemical Formula 3 in the second embodiment. Moreover, the repeating unit (Vb) on the right side in Chemical Formula 6 is the same as the repeating unit (II-b) represented by Chemical Formula 4 in the second embodiment. Therefore, detailed description is omitted here.

  The ratio of the content of the repeating unit (IV-b) and the repeating unit (Vb) in Chemical Formula 6 is not particularly limited. However, in order to express the adsorption performance by the carboxyl group and the dispersion performance by the polyoxyalkylene chain in a balanced manner, the total number of repeating units (IV-b): the total number of repeating units (Vb) is preferably 1: It is 0.1 to 1:50, More preferably, it is 1: 0.5 to 1:20, More preferably, it is 1: 1 to 1: 4.

  In the polycarboxylic acid copolymer (Ab) having a repeating unit represented by the chemical formula 6, in addition to the repeating unit (IV-b) and the repeating unit (Vb), other repeating units. May be included. Here, the specific form of the monomer forming the other repeating unit is “other monomer” in the polycarboxylic acid copolymer which is the main component of the cement dispersant of the first embodiment. It is the same. Therefore, detailed description is omitted here. In some cases, the “polyhydric alcohol alkylene oxide adduct monomer (a branched compound having a branched structure containing three or more polyoxyalkylene chains in the molecule” used in the first and second embodiments described above. Body) ”may be used as“ another monomer ”constituting the polycarboxylic acid copolymer in the present embodiment.

  In the polycarboxylic acid copolymer (Ab) having a repeating unit represented by Chemical Formula 6, the repeating unit (IV-b), the repeating unit (Vb) and other repeating units are in the form of blocks. The copolymer may be copolymerized in random, or may be copolymerized randomly.

  Here, in order to obtain a cement dispersant that exhibits excellent dispersion performance and is easily pulverized during production, two repeating units represented by the chemical formula 6 (that is, repeating units (IV-b ) And the repeating unit (Vb)) are preferably main repeating units in the polycarboxylic acid-based copolymer (Ab) having the repeating unit represented by Chemical Formula 6. Specifically, the two repeating units represented by Chemical Formula 6 ((IV-a) and (Va)) are preferably based on the total number of all repeating units of the copolymer (Ab). It is contained 70 to 99%, more preferably 80 to 95%.

  The weight average molecular weight of the polycarboxylic acid copolymer (Ab) having a repeating unit represented by Chemical Formula 6 is preferably 1,000 to 500,000 in terms of polyethylene glycol, from the viewpoint of excellent fluidity. More preferably, it is 5000-100000. In addition, the method described in the Example mentioned later is used for the measurement of the value of the said weight average molecular weight.

  In the powdery cement dispersant of the present embodiment, the polycarboxylic acid copolymer as the main component is represented by a copolymer (Aa) having a repeating unit represented by the chemical formula 5 and a chemical formula 6. Only any one of the copolymer (Ab) which has a repeating unit may be used, and both may be used together. From the viewpoint of obtaining a cement dispersant having excellent dispersibility, the powdery cement dispersant of the present embodiment preferably includes a copolymer having at least a repeating unit represented by Chemical Formula 6.

  The method for producing the polycarboxylic acid copolymer (A) in the powdery cement dispersant of the present embodiment is not particularly limited. The copolymer (A) can be synthesized by appropriately referring to conventionally known knowledge relating to polymer production. A copolymer may be synthesized based on newly obtained knowledge. At this time, a monomer corresponding to the repeating unit may be prepared as a raw material.

(Branched compound (B) having a branched structure containing three or more polyoxyalkylene chains in the molecule)
The powdery cement dispersant of the present embodiment includes a predetermined branched compound (B) in addition to the above-described polycarboxylic acid copolymer (A).

  The “polyhydric alcohol alkylene oxide adduct (B)” which is a branched compound in the present embodiment is a compound having a structure in which an oxyalkylene group is added to a polyhydric alcohol residue, and has a polymerizable unsaturated double bond. Except that it is not always necessary, it has the same form as the above-mentioned “polyhydric alcohol alkylene oxide adduct monomer”. Therefore, detailed description is omitted here.

  Here, when the powdery cement dispersant of this embodiment contains the copolymer (Aa) which has a repeating unit represented by Chemical formula 5 as a polycarboxylic acid type copolymer (A), this embodiment The ratio of the content of the polycarboxylic acid copolymer (A) and the predetermined branched compound (B) in the powdery cement dispersant of (A) / (B) with respect to the total content of 100% by mass = 50 to 98/2 to 50% by mass, more preferably 50 to 95/5 to 50% by mass, (A) / (B) = 60 to 90/10 to 40% by mass More preferably, it is particularly preferable that (A) / (B) = 70 to 85/15 to 30% by mass. It is preferable that the content of each component in the powdered cement dispersant of the present embodiment is a value within such a range from the viewpoint of excellent dispersion performance. In addition, as a value of content of each of these components, a value measured by a technique such as NMR or acid value measurement is adopted.

  About the preferable form of the average particle diameter of the powdery cement dispersant of this embodiment, it is the same as that of the preferable form in said 1st Embodiment. Therefore, detailed description is omitted here.

  As a manufacturing method of the powdery cement dispersant of this embodiment, for example, a polycarboxylic acid copolymer (Aa) having a repeating unit represented by Chemical Formula 5 and / or a repeating unit represented by Chemical Formula 6 is used. Examples include a method of preparing and mixing a polycarboxylic acid copolymer (Ab) having a predetermined amount and a predetermined branched compound (B) and then pulverizing the resulting mixture by drying. .

  At this time, the mixing means for mixing the polycarboxylic acid copolymer (A) and the predetermined branched compound (B) and the drying means for drying the resulting mixture are not particularly limited. Depending on the properties, conventionally known knowledge regarding mixing and drying of the polymer composition can be referred to as appropriate. As for the drying means, the above-mentioned form can be preferably used as well.

  The second powdery cement dispersant of the present invention has been specifically described by taking the third embodiment as an example, but the technical scope of the second powdered cement dispersant of the present invention is only the embodiment. Should not be limited to. For example, in the third embodiment described above, a polycarboxylic acid copolymer (Aa) having a repeating unit represented by Chemical Formula 5 or a polycarboxylic acid copolymer having a repeating unit represented by Chemical Formula 6 A form in which a polycarboxylic acid copolymer (A) having a repeating unit other than these is used in place of (Ab) is also included in the technical scope of the second powdery cement dispersant of the present invention. Can be done. The specific form of the polycarboxylic acid-based copolymer (A) other than the form described in detail in the third embodiment is not particularly limited, and conventionally known knowledge is appropriately referred to. 2 can be suitably used.

The above-mentioned powdery cement dispersant of the present invention is added to these compositions for the purpose of improving the dispersibility of the cement composition such as cement paste, mortar, concrete, etc. as well as known cement dispersants. Used by It can also be used for ultra high strength concrete. In the cement composition, commonly used materials such as cement, water, fine aggregate, coarse aggregate and the like can be blended. Fine powders such as fly ash, blast furnace slag, silica fume, and limestone may be added to the cement composition. Ultra-high-strength concrete is generally called as such in the field of cement composition, that is, the cured product is equivalent to the conventional one even if the water / cement ratio is smaller than that of conventional concrete. Or it means concrete that has higher strength. For example, the water / cement ratio is preferably 25% by mass or less, more preferably 20% by mass or less, further preferably 18% by mass or less, particularly preferably 14% by mass or less, and most preferably about 12% by mass or less. However, it becomes the concrete which has workability | operativity which does not interfere with normal use, The compressive strength of the hardened | cured material becomes like this. Preferably it is 60 N / mm < ² > or more, More preferably, it is 80 N / mm < ² > or more, More preferably, it is 100 N / mm ² or more, more preferably 120 N / mm ² or more, particularly preferably 160 N / mm ² or more, and most preferably shows a 200 N / mm ² or more compression strength.

As the cement, portland cement such as ordinary, early strength, ultra-early strength, rapid curing, moderate heat, white, etc., and mixed portland cement such as alumina cement, fly ash cement, blast furnace cement, silica cement and the like are suitable. The amount of cement per 1 m ³ of concrete and the amount of unit water are, for example, 100 to 185 kg / m ³ per unit of water and 10 to 70% water / cement ratio in order to produce highly durable and high strength concrete. It is preferable that More preferably, the unit water amount is 120 to 175 kg / m ³ and the water / cement ratio is 20 to 65%.

  The amount of addition to the cement composition when the powdered cement dispersant of the present invention is used is 0.01 to 1% with respect to 100% by mass of the cement composition of the present invention. It is preferable to adjust so that it may become 0 mass%. If the addition amount of the powdered cement dispersant is less than 0.01% by mass, the performance may be insufficient, and if it exceeds 1.0% by mass, the dispersibility will be improved in proportion to the increase in the addition amount. May not be seen, and there is a risk that the economic efficiency will decrease. The addition amount of the powdered cement dispersant is more preferably 0.05 to 0.5% by mass, further preferably 0.1 to 0.3% by mass with respect to 100% by mass of the cement composition. is there. In addition, the said mass% is a value of solid content conversion.

  The powdery cement dispersant of the present invention is added to the cement composition, but two or more powdered cement dispersants of the first to third embodiments of the present invention are used in combination and added to the cement composition. Also good. Other additives may be blended in the cement composition. For example, other cement dispersing agents, air entraining agents, cement wetting agents, expansion agents, waterproofing agents, retarders, quick setting agents, water-soluble polymer substances, thickeners, flocculants, drying shrinkage reducing agents, strength enhancers In addition to the powdery cement dispersant of the present invention, a hardening accelerator, an antifoaming agent and the like can be added to the cement composition.

  Preferred embodiments of the combination of the powdery cement dispersant of the present invention and other additives include the following (1) to (7).

  (1) <1> A combination comprising essentially two components of the powdered cement dispersant of the present invention and <2> an oxyalkylene antifoaming agent. As the oxyalkylene-based antifoaming agent, polyoxyalkylenes, polyoxyalkylene alkyl ethers, polyoxyalkylene acetylene ethers, polyoxyalkylene alkylamines and the like can be used. Of these, polyoxyalkylene alkylamines are particularly preferred. The blending mass ratio of the <2> oxyalkylene antifoaming agent is preferably in the range of 0.01 to 20% by mass with respect to 100% by mass of the <1> powdered cement dispersant.

  (2) A combination comprising essentially the three components of <1> the powdery cement dispersant of the present invention, <2> an oxyalkylene antifoaming agent, and <3> an AE agent. As the oxyalkylene-based antifoaming agent, polyoxyalkylenes, polyoxyalkylene alkyl ethers, polyoxyalkylene acetylene ethers, polyoxyalkylene alkylamines and the like can be used. Of these, polyoxyalkylene alkylamines are particularly preferred. As the AE agent, resin acid soaps, alkyl sulfates, and alkyl phosphates are particularly suitable. The blending mass ratio of the <2> oxyalkylene antifoaming agent is preferably in the range of 0.01 to 20% by mass with respect to 100% by mass of the <1> powdered cement dispersant. The blending mass ratio of the <3> AE agent is preferably in the range of 0.001 to 2 mass% with respect to 100 mass% of the cement composition.

  (3) <1> Powdery cement dispersant of the present invention, <2> Polyalkylene glycol mono having a polyoxyalkylene chain in which an alkylene oxide having 2 to 18 carbon atoms is added at an average addition mole number of 2 to 300 moles A copolymer comprising a (meth) acrylic acid ester monomer, a (meth) acrylic acid monomer, and a monomer copolymerizable with these monomers (Japanese Patent Publication No. 59-18338) JP, 7-223852, JP 9-2441056, etc.) and <3> an oxyalkylene-based antifoaming agent as essential components. The blending mass ratio of <1> powdered cement dispersant and <2> copolymer is preferably in the range of 5/95 to 95/5 (powdered cement dispersant / copolymer). A range of / 10 is more preferable. The blending mass ratio of the <3> oxyalkylene-based antifoaming agent is preferably in the range of 0.01 to 20% by mass with respect to a total of 100% by mass of the <1> powdered cement dispersant and the <2> copolymer. .

  (4) A combination comprising two components, <1> the powdery cement dispersant of the present invention and <2> retarder. As the retarder, oxycarboxylic acids such as gluconic acid (salt) and citric acid (salt), sugars such as glucose, sugar alcohols such as sorbitol, phosphonic acids such as aminotri (methylenephosphonic acid), and the like can be used. . The blending mass ratio of <1> powdered cement dispersant and <2> retarder is preferably in the range of 50/50 to 99.9 / 0.1 (powder cement dispersant / retarder), 70/30 The range of -99/1 is more preferable.

  (5) A combination comprising two components of <1> the powdery cement dispersant of the present invention and <2> accelerator. As the accelerator, soluble calcium salts such as calcium chloride, calcium nitrite and calcium nitrate, chlorides such as iron chloride and magnesium chloride, formates such as thiosulfate, formic acid and calcium formate, and the like can be used. The blending mass ratio of <1> powdered cement dispersant to <2> accelerator is preferably in the range of 10/90 to 99.9 / 0.1 (powder cement dispersant / accelerator), 20/80 The range of -99/1 is more preferable.

  (6) A combination comprising two components, <1> the powdery cement dispersant of the present invention and <2> a material separation reducing agent. Examples of the material separation reducing agent include various thickeners such as nonionic cellulose ethers, a hydrophobic substituent composed of a hydrocarbon chain having 4 to 30 carbon atoms as a partial structure, and an alkylene oxide having 2 to 18 carbon atoms. A compound having a polyoxyalkylene chain added at an average addition mole number of 2 to 300 moles can be used. The blending mass ratio of <1> powdered cement dispersant and <2> material separation reducing agent is preferably in the range of 10/90 to 99.99 / 0.01 (powdered cement dispersing agent / material separation reducing agent). The range of 50/50 to 99.9 / 0.1 is more preferable. The cement composition of this combination is suitable as high fluidity concrete, self-filling concrete and self-leveling material.

  (7) A combination comprising two components of <1> the powdery cement dispersant of the present invention and <2> a sulfonic acid-based dispersant having a sulfonic acid group in the molecule. Examples of sulfonic acid-based dispersants include amino sulfonic acid-based dispersions such as lignin sulfonate, naphthalene sulfonic acid formalin condensate, melamine sulfonic acid formalin condensate, polystyrene sulfonate, and aminoaryl sulfonic acid-phenol-formaldehyde condensate. An agent or the like can be used. The mass blending ratio of <1> powdered cement dispersant and <2> sulfonic acid-based dispersant is preferably in the range of 5/95 to 95/5 (powdered cement dispersant / sulfonic acid-based dispersant). The range of / 90 to 90/10 is more preferable.

  The method for preparing the concrete composition is not particularly limited, and a method similar to the conventional cement composition can be used. For example, a method of mixing the powdered cement dispersant of the present invention and cement, mixing other compounding materials as necessary, and adding water to the mixture; mixing the powdered cement dispersant of the present invention, Examples include a method of preparing a solution containing a cement dispersant by dissolving in water in advance, and adding and mixing the resulting mixture with cement and other compounding materials.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, the technical scope of this invention is not restrict | limited only to the following Example. In the following Examples, the weight average molecular weight of the polycarboxylic acid polymer was measured by GPC under the following measurement conditions.

(Production Example 1: Synthesis of polycarboxylic acid polymer (1))
A glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser was prepared. Here, 105.17 g of water was charged, and the inside of the reaction vessel was purged with nitrogen under stirring, and heated to 80 ° C. in a nitrogen atmosphere. When the internal temperature is stabilized at 80 ° C., 112.59 g of methoxypolyethylene glycol monomethacrylate (average added mole number of ethylene oxide = 25; hereinafter also referred to as “MPG25E”) forming a repeating unit represented by Chemical Formula 3 A monomer aqueous solution (213.92 g) in which 22.41 g of methacrylic acid (hereinafter also referred to as “MAA”), 77.68 g of water, and 1.23 g of 3-mercaptopropionic acid are formed in 4 hours. In addition, 29.77 g of an aqueous solution in which 1.60 g of ammonium persulfate was dissolved was dropped into the reactor in 5 hours. Thereafter, the temperature was continuously maintained at 80 ° C. for 1 hour to complete the polymerization reaction.

  After completion of the reaction, an aqueous solution (A) prepared by neutralizing with sodium hydroxide (degree of neutralization with respect to carboxylic acid = 70%) and adjusting the solid content (polycarboxylic acid polymer (1)) to 40% by mass. Got. The weight average molecular weight of the polycarboxylic acid polymer (1) contained in the obtained aqueous solution (A) was 19000. The polycarboxylic acid polymer (1) is a polymer having a repeating unit represented by Chemical Formula 3 and a repeating unit represented by Chemical Formula 4.

(Production Example 2: Synthesis of polycarboxylic acid polymer (2))
The solid content (polycarboxylic acid polymer (2)) was adjusted to 40% by mass in the same manner as in Production Example 1 except that neutralization was performed using calcium hydroxide instead of sodium hydroxide. An adjusted aqueous solution (B) was obtained. The polycarboxylic acid polymer (2) is also a polymer having repeating units represented by Chemical Formula 3 and Chemical Formula 4.

(Production Example 3: Synthesis of polycarboxylic acid polymer (3))
A glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser was prepared. Here, 113.57 g of water, and 3-methyl-3-buten-1-ol / ethylene oxide adduct forming the repeating unit represented by Chemical Formula 1 (average number of moles of added ethylene oxide = 50; hereinafter, “ 112.59 g) (also referred to as “IPN50”) was charged, and the reaction vessel was purged with nitrogen under stirring and heated to 60 ° C. in a nitrogen atmosphere. When the internal temperature was stabilized at 60 ° C., 0.5 g of hydrogen peroxide was added. Thereafter, 18.75 g of an aqueous monomer solution obtained by mixing 15.01 g of acrylic acid (hereinafter also referred to as “AA”) forming a repeating unit represented by Chemical Formula 2 and 3.74 g of water in 3 hours, and 3-mercaptopropion 24.37 g of an aqueous solution in which 0.44 g of acid and 0.23 g of L-ascorbic acid were dissolved was dropped into the reactor in 3.5 hours. Thereafter, the temperature was continuously maintained at 60 ° C. for 1 hour to complete the polymerization reaction.

  After completion of the reaction, neutralization was performed using sodium hydroxide to obtain an aqueous solution (C) in which the solid content (polycarboxylic acid polymer (3)) was adjusted to 40% by mass. The weight average molecular weight of the polycarboxylic acid polymer (3) contained in the obtained aqueous solution (C) was 34000. The polycarboxylic acid polymer (3) is a polymer having a repeating unit represented by Chemical Formula 1 and a repeating unit represented by Chemical Formula 2.

(Production Example 4: Synthesis of polycarboxylic acid polymer (4))
40% by mass of solid content (polycarboxylic acid polymer (4)) is contained in the same manner as in Production Example 3 except that it is neutralized using calcium hydroxide instead of sodium hydroxide. An aqueous solution (D) was obtained. The polycarboxylic acid polymer (4) is also a polymer having a repeating unit represented by Chemical Formula 1 and a repeating unit represented by Chemical Formula 2.

(Production Example 5: Synthesis of polyhydric alcohol alkylene oxide adduct (1))
In a pressure vessel equipped with a stirrer, a pressure gauge, and a thermometer, 64 g of commercially available sorbitol and 0.20 g of sodium hydroxide were charged. Next, the temperature of the reaction system was raised to 120 ° C. or higher to melt sorbitol. Thereafter, 936 g of ethylene oxide was added while maintaining the reaction system at 120 to 140 ° C. to obtain a compound in which 10 mol of ethylene oxide was added to each active hydrogen of sorbitol (hereinafter also referred to as “SB600”).

(Production Example 6: Synthesis of polyhydric alcohol alkylene oxide adduct (2))
In a pressure vessel equipped with a stirrer, a pressure gauge, and a thermometer, 517 g of SB600 synthesized in Production Example 5 and 0.10 g of sodium hydroxide were charged. Next, after raising the temperature of the reaction system, 483 g of ethylene oxide was added while maintaining the reaction system at 120 to 140 ° C., and a compound in which 20 moles of ethylene oxide was added to each active hydrogen of sorbitol (hereinafter referred to as “SB1200”). Also referred to as “).

(Production Example 7: Synthesis of polyhydric alcohol alkylene oxide adduct (3))
In a pressure vessel equipped with a stirrer, a pressure gauge, and a thermometer, 176 g of SB600 synthesized in Production Example 5 and 0.16 g of sodium hydroxide were charged. Next, after raising the temperature of the reaction system, 824 g of ethylene oxide was added while maintaining the reaction system at 120 to 140 ° C., and a compound in which 60 mol of ethylene oxide was added to each active hydrogen of sorbitol (hereinafter referred to as “SB3600”). Also referred to as “).

(Example 1: Synthesis of polycarboxylic acid copolymer in the second embodiment, and preparation of a precursor aqueous solution of the cement dispersant of the second embodiment containing the copolymer)
A glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux cooling device was prepared. Here, 300 g of SB3600 synthesized in Production Example 7 and 0.08 g of sodium hydroxide were charged, and the temperature was raised to 90 ° C. in an air atmosphere. When the internal temperature was stabilized at 90 ° C., 22.9 g of glycidyl methacrylate was added in 1 hour. After completion of the addition, stirring was continued at 90 ° C. for 2 hours to obtain a sorbitol / ethylene oxide adduct monomer (hereinafter also referred to as “SB / EO adduct monomer”).

  A glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser was separately prepared. Here, 82.5 g of water was charged, and the inside of the reaction vessel was purged with nitrogen under stirring and heated to 80 ° C. in a nitrogen atmosphere. When the internal temperature is stabilized at 80 ° C., 72.3 g of methoxypolyethylene glycol monomethacrylate (average number of moles of added ethylene oxide = 25) forming a repeating unit represented by Chemical Formula 3 is formed, and the repeating unit represented by Chemical Formula 4 is formed. A monomer aqueous solution in which 22.5 g of methacrylic acid, 25.2 g of the SB / EO adduct monomer synthesized above, 64.6 g of water, and 2.88 g of 3-mercaptopropionic acid as a chain transfer agent were mixed, and 4 22.5 g of a 6% ammonium persulfate aqueous solution was added dropwise over 3 hours. Thereafter, the temperature was continuously maintained at 80 ° C. for 1 hour to complete the polymerization reaction.

  After completion of the reaction, neutralization was performed using sodium hydroxide to obtain an aqueous solution (1) containing 40% by mass of a solid content (polycarboxylic acid copolymer (5)). The weight average molecular weight of the polycarboxylic acid copolymer (5) was 25000.

  About the aqueous solution (1) obtained above, pulverization mentioned below was tried and it was evaluated whether pulverization was possible.

(Example 2: Synthesis of the precursor of the cement dispersant of the third embodiment by synthesis of the polycarboxylic acid copolymer in the second embodiment and mixing of the copolymer and the polyhydric alcohol alkylene oxide adduct) Preparation)
A glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser was prepared. Here, 82.5 g of water was charged, and the inside of the reaction vessel was purged with nitrogen under stirring and heated to 80 ° C. in a nitrogen atmosphere. When the internal temperature is stabilized at 80 ° C., 84.3 g of methoxypolyethylene glycol monomethacrylate (average number of added moles of ethylene oxide = 25) forming a repeating unit represented by Chemical Formula 3 and forming a repeating unit represented by Chemical Formula 4 A monomer aqueous solution in which 22.5 g of methacrylic acid, 13.2 g of the SB / EO adduct monomer synthesized above, 64.6 g of water, and 2.88 g of 3-mercaptopropionic acid as a chain transfer agent were mixed, and 4 22.5 g of a 6% ammonium persulfate aqueous solution was added dropwise over 3 hours. Thereafter, the temperature was continuously maintained at 80 ° C. for 1 hour to complete the polymerization reaction.

  After completion of the reaction, neutralization treatment was performed using sodium hydroxide to obtain an aqueous solution containing 40% by mass of solid content (polycarboxylic acid copolymer (6)). The polycarboxylic acid copolymer had a weight average molecular weight of 22,000.

  By adding 1 g of an aqueous solution containing 40% by mass of SB3600 to 49 g of an aqueous solution containing 40% by mass of the polycarboxylic acid copolymer (6), and mixing until the system is uniform, the solid content (polycarboxylic acid An aqueous solution (2) containing 40% by mass of a copolymer (6) + SB3600) was obtained.

  About the aqueous solution (2) obtained above, pulverization mentioned later was tried and it was evaluated whether it could be pulverized.

(Example 3: Preparation of precursor aqueous solution of cement dispersant of third embodiment)
By adding 10 g of an aqueous solution containing 40% by mass of SB3600 to 50 g of the aqueous solution (A) obtained in Production Example 1, solid content (polycarboxylic acid polymer (1 ) + SB3600) in an aqueous solution (3) containing 40% by mass.

  About the aqueous solution (3) obtained above, pulverization mentioned below was tried and it was evaluated whether it could be pulverized.

(Example 4: Preparation of precursor aqueous solution of cement dispersant of third embodiment)
By adding 7.5 g of an aqueous solution containing 40% by mass of SB3600 to 50 g of the aqueous solution (B) obtained in Production Example 2 above, the solid content (polycarboxylic acid polymer) is mixed until the system is uniform. An aqueous solution (4) containing 40% by mass of (2) + SB3600) was obtained.

  About the aqueous solution (4) obtained above, pulverization mentioned below was tried and it was evaluated whether it could be pulverized.

(Example 5: Preparation of precursor aqueous solution of cement dispersant of third embodiment)
By adding 10 g of an aqueous solution containing 40% by mass of SB1200 synthesized in the above Production Example 6 to 50 g of the aqueous solution (C) obtained in the above Production Example 3, and mixing until the system is uniform, An aqueous solution (5) containing 40% by mass of (polycarboxylic acid polymer (3) + SB1200) was obtained.

  About the aqueous solution (5) obtained above, pulverization mentioned below was tried and it was evaluated whether it could be pulverized.

(Example 6: Preparation of precursor aqueous solution of cement dispersant of third embodiment)
By adding 5.5 g of an aqueous solution containing 40% by mass of SB1200 to 50 g of the aqueous solution (D) obtained in Production Example 4 above, the solid content (polycarboxylic acid polymer) is mixed until the system is uniform. An aqueous solution (6) containing 40% by mass of (4) + SB1200) was obtained.

  About the aqueous solution (6) obtained above, pulverization mentioned below was tried and it was evaluated whether it could be pulverized.

(Example 7: Preparation of precursor aqueous solution of cement dispersant of third embodiment)
50 g of the aqueous solution (A) obtained in Production Example 1 above, a polyglycerin / ethylene oxide compound (a compound obtained by adding 60 mol of ethylene oxide to all active hydrogens of polyglycerin (n = 4), respectively; 10 g of an aqueous solution containing 40% by mass of “PG30”) is added and mixed until the inside of the system becomes uniform, whereby an aqueous solution containing 40% by mass of the solid content (polycarboxylic acid polymer (1) + PG30) (7 )

  About the aqueous solution (7) obtained above, pulverization mentioned below was tried and it was evaluated whether it could be pulverized.

(Example 8: Preparation of precursor aqueous solution of cement dispersant of third embodiment)
To 50 g of the aqueous solution (A) obtained in Production Example 1 above, a trimethylolpropane / ethylene oxide compound (a compound obtained by adding 60 moles of ethylene oxide to all active hydrogens of trimethylolpropane; hereinafter, “TEP60”) 10 g of an aqueous solution containing 40% by mass), and mixing until the system is uniform, thereby obtaining an aqueous solution (8) containing 40% by mass of solid content (polycarboxylic acid polymer (1) + TEP60). It was.

  About the aqueous solution (8) obtained above, pulverization mentioned below was tried and it was evaluated whether it could be pulverized.

(Comparative Example 1)
The aqueous solution (A) obtained in Production Example 1 was tried to be pulverized as described later, and was evaluated whether it could be pulverized.

(Comparative Example 2)
The aqueous solution (B) obtained in Production Example 2 was tried to be pulverized as described later, and was evaluated whether it could be pulverized.

(Comparative Example 3)
10 g of an aqueous solution containing 40% by mass of polyethylene oxide (molecular weight = 4000; hereinafter also referred to as “PEG”) is added to 50 g of the aqueous solution (A) obtained in Production Example 1 and mixed until the system is uniform. By doing this, the aqueous solution (E) containing 40 mass% of solid content (polycarboxylic acid type polymer (1) + PEG) was obtained.

  About the aqueous solution (E) obtained above, pulverization mentioned below was tried and it was evaluated whether it could be pulverized.

(Powdering test)
The pulverization of the aqueous solutions (1 to 8, A, B, and E) obtained in each of the above Examples and Comparative Examples was performed by the following method.

Each aqueous solution was supplied to a glass petri dish having a diameter of 13 cm so that the solid content after drying was 20 g. This was left in an environment of 50 ° C. and 50 Torr (about 6.7 × 10 ³ Pa) for 24 hours to remove moisture. After drying, the obtained solid was left in a desiccator for 1 day, and the resulting product was pulverized using a mortar. The pulverized powder was passed through a 16-mesh sieve to obtain a powdered cement dispersant having a certain particle size distribution.

  It was evaluated whether powdering by the above process was possible. The evaluation results are shown in Table 3 below. Evaluation is that the polymer after drying can be pulverized and a powdery cement dispersant having fluidity is obtained, ◯ that the powder is difficult to peel from the petri dish and difficult to be powdered, candy-like or sticky A film having a film shape that could not be crushed was marked as x.

  From the results shown in Table 3, the polycarboxylic acid polymer, which is the main component of the cement dispersant, is copolymerized with the polyhydric alcohol alkylene oxide adduct monomer, or the polycarboxylic acid polymer and the polyhydric alcohol. It is shown that by mixing with the alkylene oxide adduct, powdering of the aqueous solution containing the polymer is facilitated by drying, and a powdery cement dispersant is obtained. Further, an aqueous solution further containing a polyhydric alcohol alkylene oxide adduct in a copolymer obtained by copolymerizing a polycarboxylic acid polymer as a main component of the cement dispersant with a polyhydric alcohol alkylene oxide adduct monomer. It is shown that a powdery cement dispersant having extremely excellent fluidity can be obtained by pulverizing the powder.

(Mortar test)
For the purpose of investigating the dispersibility of the powdery cement dispersant of the present invention, the powdered cement dispersant obtained by pulverizing the aqueous solution (3) obtained in Example 3 and obtained in Comparative Example 3 were used. The polymer mass obtained in the pulverization step of the aqueous solution (E) was added to each mortar, and a mortar test was performed. The powdered cement dispersant derived from Example 3 was added as a powder. On the other hand, the polymer mass derived from Comparative Example 3 was added so as to be dissolved in water in the mortar.

  The mortar formulation is as follows.

  The mortar flow was measured according to the flow test of JIS R 5201 using a mixer according to the method of kneading of 10.4.3 of JIS R 5201 and a kneading method. The measurement results are shown in Table 5 below.

  From the results shown in Table 5, it can be seen that a higher mortar flow can be obtained with the powdered cement dispersant of the present invention if the addition amount is the same. The powdered cement dispersant of the present invention is pulverized. Not only is easy, but also has excellent dispersibility

  The powdery cement dispersant of the present invention is used for the purpose of improving the dispersibility of the cement composition. Since the powdery cement dispersant of the present invention is a powder, it is easy to handle and is excellent in dispersion performance.

Claims (10)

A repeating unit (I) derived from an unsaturated polyalkylene glycol monomer;
A repeating unit (II) derived from an unsaturated carboxylic acid monomer;
A repeating unit (III) derived from a branched compound monomer having a branched structure containing three or more polyoxyalkylene chains in the molecule;
A powdery cement dispersant comprising a polycarboxylic acid copolymer having a main component as a main component. The powdery cement dispersant according to claim 1, wherein the repeating unit (I) is represented by the following chemical formula 1, and the repeating unit (II) is represented by the following chemical formula 2:

In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and AO independently represents an oxy having 2 to 18 carbon atoms. Represents an alkylene group, R ^a represents an alkylene group having 0 to 2 carbon atoms, n represents an average number of added moles of the oxyalkylene group, is 2 to 300, and R ³ and R ⁴ are each independently And represents a hydrogen atom, a methyl group or —COOM ² (except when both R ³ and R ⁴ are —COOM ² ), and R ⁵ represents a hydrogen atom, a methyl group or —CH ₂ COOM ³ . (Wherein R ⁵ is —CH ₂ COOM ³ , R ³ and R ⁴ each independently represents a hydrogen atom or a methyl group), M ¹ , M ² and M ³ are each independently Hydrogen atom, metal source , An ammonium group or an organic amine group. The powdery cement dispersant according to claim 1, wherein the repeating unit (I) is represented by the following chemical formula 3, and the repeating unit (II) is represented by the following chemical formula 4:

In the formula, R ⁶ represents a hydrogen atom or a methyl group, R ⁷ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and BO is independently an oxy having 2 to 18 carbon atoms. Represents an alkylene group, p represents an average addition mole number of the oxyalkylene group, is 2 to 300, R ⁸ represents a hydrogen atom or a methyl group, and R ⁹ represents a hydrogen atom, a methyl group or —CH _2. COOM ⁵ is represented, and M ⁴ and M ⁵ each independently represent a hydrogen atom, a metal atom, an ammonium group or an organic amine group.   The ratio of the content of the repeating unit (I), the repeating unit (II) and the repeating unit (III) in the polycarboxylic acid copolymer is based on a total content of these repeating units of 100% by mass. The powdery cement dispersant according to any one of claims 1 to 3, wherein (I) / (II) / (III) = 40 to 90/5 to 30/5 to 50 mass%. A polycarboxylic acid copolymer (A) having a repeating unit (IV) derived from an unsaturated polyalkylene glycol monomer and a repeating unit (V) derived from an unsaturated carboxylic acid monomer;
A branched compound (B) having a branched structure containing three or more polyoxyalkylene chains in the molecule;
A powdered cement dispersant. The powdery cement dispersant according to claim 5, wherein the polycarboxylic acid copolymer (A) has a repeating unit represented by the following chemical formula 5 or 6:

In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and AO independently represents an oxy having 2 to 18 carbon atoms. Represents an alkylene group, R ^a represents an alkylene group having 0 to 2 carbon atoms, n represents an average number of added moles of the oxyalkylene group, is 2 to 300, and R ³ and R ⁴ are each independently And represents a hydrogen atom, a methyl group or —COOM ² (except when both R ³ and R ⁴ are —COOM ² ), and R ⁵ represents a hydrogen atom, a methyl group or —CH ₂ COOM ³ . (Wherein R ⁵ is —CH ₂ COOM ³ , R ³ and R ⁴ each independently represents a hydrogen atom or a methyl group), M ¹ , M ² and M ³ are each independently Hydrogen atom, metal source , An ammonium group or an organic amine group,

In the formula, R ⁶ represents a hydrogen atom or a methyl group, R ⁷ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and BO is independently an oxy having 2 to 18 carbon atoms. Represents an alkylene group, p represents an average addition mole number of the oxyalkylene group, is 2 to 300, R ⁸ represents a hydrogen atom or a methyl group, and R ⁹ represents a hydrogen atom, a methyl group or —CH _2. COOM ⁵ is represented, and M ⁴ and M ⁵ each independently represent a hydrogen atom, a metal atom, an ammonium group or an organic amine group.   The ratio of the content of the polycarboxylic acid copolymer (A) and the branched compound (B) is (A) / (B) = 50 to 98/2 with respect to the total content of 100% by mass. The powdery cement dispersant according to claim 5 or 6, which is 50% by mass.   The powdery cement dispersant according to claim 6 or 7, wherein the polycarboxylic acid copolymer (A) has a repeating unit represented by the chemical formula 6.   The branched compound is a polyhydric alcohol alkylene oxide adduct having a structure in which an oxyalkylene group is bonded to a polyhydric alcohol residue having an average of 3 or more hydroxyl groups per molecule. 2. The powdery cement dispersant according to item 1.   The powdery cement dispersant according to claim 9, wherein an average value of the number of hydroxyl groups of one molecule of the polyhydric alcohol constituting the polyhydric alcohol alkylene oxide adduct is 3 to 300.