JP2006182606A - Cement admixture and cement composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cement admixture, which is excellent in the dispersion stability of cement particles and in water-reducing activities without reduction in the molecular weight of a polymer and remaining of unreacted materials, compared with conventional cement admixtures consisting of polymers of (meth)acrylate polyoxyalkylene glycol. <P>SOLUTION: The cement admixture consists of a polymer of water-soluble (meth)acrylate polyoxyalkylene glycol ester expressed by formula (a) (wherein, R<SB>1</SB>is hydrogen or a methyl group; R<SB>2</SB>is a 1-30C hydrocarbon group; AO is a 2-4C oxyalkylene group; and n shows a number of 1-300) that is obtained by carrying out transesterification of a glycol compound and (meth)acrylic ester by using a titanium alkoxide and/or a zirconium alkoxide as an esterification catalyst, and then treating the reaction mixture with water to separate and remove insoluble materials. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cement admixture and a cement composition using the admixture.

    Conventionally, naphthalene sulfonic acid formaldehyde condensate salt, melamine sulfonic acid formaldehyde condensate salt, lignin sulfonic acid formaldehyde condensate salt, etc. are known as cement dispersants used for the purpose of improving the fluidity of cement compositions such as concrete. It was. However, conventional cement dispersants do not always have a sufficient effect of dispersing the cement particles, but the so-called slump loss is large and the slurry thickens, so that the workability at the time of placement on site is significantly reduced. When the cement composition slurry is poured into the container, there is a problem that unfilling is likely to occur when compaction or the like is delayed. Furthermore, if the amount of unit water in the cement composition is too large, the required strength after curing cannot be obtained, so a sufficient water-reducing effect is required for cement dispersants. There was something that was not enough. In order to solve these problems, a cement dispersant containing a polycarboxylic acid-based copolymer has been used in recent years, and it is highly effective in improving strength after curing as an admixture exhibiting excellent water reduction with respect to the cement composition. Because of its performance, it is widely used for civil engineering and construction in place of conventional dispersants. However, none of these dispersants satisfy all the requirements such as water reduction, sustainability of the slump, workability, and strength when used in concrete.

  In recent years, (meth) acrylic acid polyalkylene glycol ester polymers have been used to solve the problems of the conventional cement dispersants. (Meth) acrylic acid polyalkylene glycol ester can be obtained by transesterification between glycol compound such as polyoxyalkylene glycol obtained by adding alkylene oxide to alcohol and (meth) acrylic acid ester. Compared to the polymer of (meth) acrylic acid polyalkylene glycol ester obtained by transesterification reaction using styrene, the polymer of (meth) acrylic acid polyalkylene glycol ester obtained by transesterification with a basic catalyst is cement dispersed. It is said that the water-reducing property as an agent is greatly improved (Patent Document 1).

Japanese Patent No. 3327809

  In Patent Document 1, when a transesterification reaction between a glycol compound and a (meth) acrylic acid ester is performed, an alkali metal hydroxide such as sodium hydroxide or an alkaline earth metal hydroxide such as calcium hydroxide is used as a basic catalyst. Products, alkali metal alkoxides such as sodium methoxide, sodium ethoxide, and the like, and strongly basic ion exchange resins having an ammonium-type amine as an exchange group are disclosed. However, when transesterification of (meth) acrylic acid ester having a highly reactive double bond in the presence of these strongly basic catalysts, a glycol compound is added to the double bond part of (meth) acrylic acid ester. There is a problem that by-products such as those added by the reaction and alcohol by-produced by the reaction are added to the double bond portion, and catalysts such as sodium alkoxide are deactivated during the reaction. As a result, a cement dispersant using a polymer of a (meth) acrylic acid polyalkylene glycol ester obtained by a transesterification reaction using a basic catalyst is obtained. A water-soluble (meth) acrylic acid polyalkylene glycol ester of good quality cannot be obtained, and a cement admixture is produced using this. Unreacted glycolate to - or not sufficient dispersion performance is obtained for Le compounds are mixed, gelation occurs during the production, there is a problem such that desired polymer can not be obtained.

  As a result of diligent research to solve the above-mentioned problems, the inventors of the present invention obtained a water-soluble (meth) acrylic acid polyoxyalkylene glycol ester obtained by removing a water-insoluble component after a transesterification reaction using a specific catalyst. The present inventors have found that a cement dispersant obtained by polymerization can solve the above-mentioned conventional problems and have completed the present invention.

（２）グリコール化合物が、エチレンオキシド成分２０重量％以上含有する下記式（ｂ）で示される化合物である上記（１）のセメント混和剤、

（３）水溶性（メタ）アクリル酸ポリオキシアルキレングリコールエステルと、他のモノマーとの共重合体よりなる上記（１）又は（２）のセメント混和剤、
（４）水溶性（メタ）アクリル酸ポリオキシアルキレングリコールエステルと、下記式（ｃ）で示される不飽和カルボン酸系モノマーとの共重合体である上記（３）のセメント混和剤、

（５）水溶性（メタ）アクリル酸ポリオキシアルキレングリコールエステルと、下記式（ｃ）で示される不飽和カルボン酸系モノマー及び、これらと共重合可能な他のモノマーとの共重合体である上記（３）のセメント混和剤、

（６）水溶性（メタ）アクリル酸ポリオキシアルキレングリコールエステル１０〜９５重量％と、不飽和カルボン酸系モノマー２〜４５重量％と、これらと共重合可能な他のモノマー５０重量％以下（但し０重量％は除き、３者の合計は１００重量％である。）との共重合体である上記（５）のセメント混和剤、
（７）上記（１）〜（６）のいずれかに記載のセメント混和剤と、水及びセメントを含むことを特徴とするセメント組成物、
を要旨とするものである。 That is, the present invention
(1) Obtained by subjecting a glycol compound and (meth) acrylic acid ester to a transesterification reaction using titanium alkoxide and / or zirconium alkoxide as a transesterification catalyst, and then treating with water to separate and remove insoluble components. A cement admixture comprising a water-soluble (meth) acrylic acid polyoxyalkylene glycol ester polymer represented by the following formula (a):

(2) The cement admixture of the above (1), wherein the glycol compound is a compound represented by the following formula (b) containing 20% by weight or more of an ethylene oxide component,

(3) The cement admixture according to (1) or (2), comprising a copolymer of a water-soluble (meth) acrylic acid polyoxyalkylene glycol ester and another monomer,
(4) The cement admixture of (3) above, which is a copolymer of a water-soluble (meth) acrylic acid polyoxyalkylene glycol ester and an unsaturated carboxylic acid monomer represented by the following formula (c):

(5) The above-mentioned copolymer which is a copolymer of a water-soluble (meth) acrylic acid polyoxyalkylene glycol ester, an unsaturated carboxylic acid monomer represented by the following formula (c), and other monomers copolymerizable therewith (3) cement admixture,

(6) 10-95% by weight of water-soluble (meth) acrylic acid polyoxyalkylene glycol ester, 2-45% by weight of unsaturated carboxylic acid monomer, and 50% by weight or less of other monomers copolymerizable therewith (however, The total amount of all three is 100% by weight except 0% by weight.) The cement admixture of (5) above, which is a copolymer with
(7) A cement composition comprising the cement admixture according to any one of (1) to (6) above, water and cement,
Is a summary.

  The cement admixture of the present invention has a high purity with little by-product during the production of (meth) acrylic acid polyoxyalkylene glycol ester used as a raw material, and does not inhibit the polymerization reaction. The cement admixture of the present invention obtained by polymerization using an oxyalkylene glycol ester has a lower molecular weight than the conventional cement admixture made of a polyoxyalkylene glycol ester polymer of (meth) acrylic acid. , No unreacted material remains. Moreover, since the cement admixture of the present invention contains little molecular weight and no by-products, it has effects such as high water reduction and dispersion stability.

  The cement admixture of the present invention is a polymer of a water-soluble (meth) acrylic acid polyalkylene glycol ester represented by the following formula (a). This water-soluble (meth) acrylic acid polyalkylene glycol ester contains titanium alkoxide and / or Alternatively, zirconium alkoxide can be used as a transesterification catalyst, and a glycol compound and a (meth) acrylic ester can be transesterified.

  As the glycol compound, homopolymers or copolymers of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, polyoxyalkylene glycols that are copolymers, and addition polymerization of one or more of the above alkylene oxides to alcohols, Examples include alkoxypolyoxyalkylene glycols obtained by reacting alkyl halides with the above polyoxyalkylene glycols to alkoxylate the polyoxyalkylene glycols.

  Examples of preferred polyoxyalkylene glycols include polyethylene glycol, polypropylene glycol, polybutylene glycol, polyethylene-polypropylene glycol, polyethylene-polybutylene glycol, polyethylene-polypropylene-polybutylene glycol. In addition, as a preferable example of alkoxy polyoxyalkylene glycol, an alkoxy group is methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, 2-ethylhexyl alcohol, decyl alcohol, lauryl alcohol, Carbon such as saturated and unsaturated aliphatic alcohols such as myristyl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, alicyclic alcohols such as cyclohexyl alcohol, and aromatic alcohols such as octylphenol, nonylphenol, and dodecylphenol. What is a group derived from an alcohol having a hydrocarbon group of 1 to 30 is exemplified. For example, methoxy polyoxyalkylene glycol, ethoxy polyoxyalkylene glycol, propoxy polyoxyalkylene glycol, butoxy polyoxyalkylene glycol, hexyl alkoxy polyoxyalkylene glycol, cyclohexyl alkoxy polyoxyalkylene glycol, 2-ethylhexyl alkoxy polyoxy Examples include alkylene glycol, cetyl alkoxy polyoxyalkylene glycol, stearyl alkoxy polyoxyalkylene glycol, methylphenoxy polyoxyalkylene glycol, nonylphenoxy polyoxyalkylene glycol, decylphenoxy polyoxyalkylene glycol, and naphthoxy polyoxyalkylene glycol. Alkoxypolyoxyalkyl The oxyalkylene groups in the glycol, polyoxyethylene, include oxypropylene and or oxybutylene. Among these, a glycol compound represented by the following formula (b) is preferable.

In producing a water-soluble (meth) acrylic acid polyalkylene glycol ester, water is added to the reaction product produced by the transesterification method, and then impurities are filtered, so that the material to be filtered is liquid in the filtration process. There is a need. For this reason, although the to-be-filtered object is heated as needed in the filtration treatment step, the filtration treatment is preferably performed at room temperature or with little heating. In the glycol compound represented by the above formula (b), if the carbon number of R ₃ becomes too large, the filtration treatment must be performed at a high temperature, and if the number of added moles of alkylene oxide: n increases, transesterification occurs. Since the reactivity at the time of the reaction is lowered, in order to obtain a (meth) acrylic acid polyalkylene glycol ester more effectively, R ₃ in the above formula (b) is hydrogen or a compound having 1 to 4 carbon atoms as a glycol compound. A hydrocarbon group having n of 5 to 50 is preferred. Specifically, polyoxyethylene (10 mol) glycol, polyoxyethylene (20 mol) polyoxypropylene (10 mol) glycol, methoxy polyoxyethylene (10 mol) glycol, methoxy polyoxyethylene (30 mol) Glycol, methoxypolyoxyethylene (20 mol) polyoxypropylene (10 mol) glycol, ethoxypolyoxyethylene (10 mol) glycol, propoxypolyoxyethylene (25 mol) glycol, butoxypolyoxyethylene (10 mol) glycol Etc.

  In obtaining alkoxy polyoxyalkylene glycol, the method of addition polymerization of alkylene oxide to alcohols includes metals such as metal sodium and metal potassium, various metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, Alkaline earth metal compounds such as magnesium hydroxide and calcium hydroxide, various carbonates such as sodium carbonate, metal alcoholates such as sodium methylate and potassium methylate, boron trifluoride ether, tin chloride, zeolite, etc. Using a known polymerization catalyst such as an acidic catalyst such as a basic catalyst, a protonic acid, a Lewis acid, and a solid acid, an alkylene oxide is converted to an alcohol at a temperature of about 50 to 200 ° C., anionic polymerization, cationic polymerization, coordination anionic polymerization, etc. It can be obtained by addition polymerization by a known method.

  When the polyoxyalkylene group of the polyoxyalkylene glycol or alkoxy polyoxyalkylene glycol is composed of two or more alkylene oxides, the alkylene oxide may be randomly polymerized or block polymerized, In order to obtain a (meth) acrylic acid polyalkylene glycol ester having good properties, random polymerization is preferred. In order to obtain a (meth) acrylic acid polyalkylene glycol ester having good water solubility, the alkylene oxide component constituting the polyoxyalkylene group preferably contains 20% by weight or more of an ethylene oxide component.

  Examples of the (meth) acrylate ester to be transesterified with the glycol compound include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, And lower alcohol esters of (meth) acrylic acid, such as isobutyl (meth) acrylate.

  In the present invention, the titanium alkoxide used as a transesterification catalyst between the glycol compound and the (meth) acrylic acid ester includes tetramethoxy titanium, tetraethoxy titanium, tetra normal propoxy titanium, tetraisopropoxy titanium, tetra normal butoxy titanium, tetra Examples include isobutoxy titanium. Examples of the zirconium alkoxide include tetramethoxyzirconium, tetraethoxyzirconium, tetranormalpropoxyzirconium, tetraisopropoxyzirconium, tetranormalbutoxyzirconium, tetraisobutoxyzirconium and the like. Titanium alkoxide and zirconium alkoxide can be used alone or in combination of two or more. The addition amount of a catalyst such as titanium alkoxide or zirconium alkoxide is preferably 0.01 to 10% by weight, more preferably 0.1 to 5% by weight, based on the weight of the glycol compound. When the amount of the catalyst is less than 0.01% by weight of the glycol compound weight, the effect as a catalyst is insufficient, and even if the amount exceeds 10% by weight, the transesterification reaction efficiency is improved in proportion to the amount added. It is uneconomical. Moreover, since the hue of the reaction product by transesterification is superior to that of titanium alkoxide, zirconium alkoxide is preferably used for obtaining a water-soluble (meth) acrylic acid polyalkylene glycol ester having a more excellent hue. .

  Both transesterification and continuous methods can be employed for the transesterification reaction between the glycol compound and the (meth) acrylic acid ester. Usually, the glycol compound and (meth) acrylic are contained in a reaction vessel equipped with a reflux tower. The reaction is conducted while heating and refluxing by adding an acid ester, a catalyst titanium alkoxide and / or zirconium alkoxide, a polymerization inhibitor and a solvent such as hydrocarbons, hexane, toluene, cyclohexane as necessary. As the polymerization inhibitor, for example, hydroquinone, hydroquinone monomethyl ether, phenothiazine, phenol derivatives, catechols, amines and the like are used and added in the range of 50 to 5000 ppm of the total amount of glycol compound and (meth) acrylic acid ester. The molar ratio of the glycol compound to the (meth) acrylic acid ester is preferably glycol compound: (meth) acrylic acid ester = 1: 1 to 1:20, more preferably 1: 3 to 1:10. When the ratio of (meth) acrylic acid ester is less than 1 mole per mole of glycol compound, unreacted glycol compound remains as an impurity. The use of more than 20 moles of (meth) acrylic acid ester is uneconomical. The transesterification reaction has a reaction temperature of 80 to 140 ° C., a reflux ratio of 1: 1 to 15: 1, and the reflux tower top temperature varies depending on the (meth) acrylic acid ester used as a raw material, but (meth) acrylic acid is present in excess. An appropriate azeotropic temperature is preferable for efficiently distilling the alcohol produced by the ester exchange reaction with the ester out of the reaction system. For example, 60-80 ° C. is suitable for the reaction with methyl (meth) acrylate. If the reaction temperature is less than 80 ° C., the reaction efficiency is poor, and if it exceeds 140 ° C., side reactions such as polymerization tend to occur. On the other hand, if the reflux ratio is out of the above range, the alcohol produced by the reaction may not be efficiently distilled out of the reaction system. The transesterification reaction can be carried out at normal pressure, but the alcohol produced by the reaction can be efficiently distilled out from the reaction vessel by carrying out under reduced pressure. The transesterification rate can be calculated from this value by measuring the residual amount of glycol compound by measuring liquid chromatography or hydroxyl value. The reaction time varies depending on the molar ratio of raw materials, the amount of catalyst, the reaction temperature, the reflux ratio and the like, but is usually almost completed in about 5 to 15 hours. Unreacted (meth) acrylic acid ester remaining in the reaction system and the solvent added as necessary can be removed by distillation under reduced pressure.

  After the above reaction is completed, water is added, and the water-soluble (meth) acrylic acid polyalkylene glycol ester produced by the transesterification reaction between the glycol compound and the (meth) acrylic acid ester is dissolved in water, and filtered. Separate and remove water insolubles. By this treatment, titanium alkoxide and zirconium alkoxide used as a transesterification catalyst are removed. The amount of water added is appropriately selected depending on the type of the reacted (meth) acrylic acid polyalkylene glycol ester, but the smallest amount necessary to separate and remove water-insoluble components such as titanium alkoxide and zirconium alkoxide is added. It is preferable. When there is too little addition amount of water, the purity of the (meth) acrylic-acid polyalkylene glycol ester will fall. Usually, addition of an equimolar amount or more of water per mole of metal alkoxide (total of titanium alkoxide and zirconium alkoxide) is preferable, and the larger the amount of water, the easier the catalyst becomes and the removal becomes easier. Preferably, it is the same amount or more by weight, more preferably 5 times or more, still more preferably 20 times or more. When the amount of water is less than equimolar with respect to the metal alkoxide, the metal alkoxide is insufficiently insoluble in water and may remain as an impurity in the (meth) acrylic acid polyalkylene glycol ester. Also, if the amount of water added is too large, the efficiency when removing water from the (meth) acrylic acid polyalkylene glycol ester may be reduced as necessary after removing impurities. Is within a range that can remove impurities, and the addition amount is preferably 200 times or less of the catalyst amount.

  When removing the insoluble matter after the transesterification reaction, if an adsorbent is used together with water, the hue can be improved and the remaining acid content can be reduced. An alkylene glycol ester can be obtained, and this is preferable because the dispersibility of the cement admixture produced using the alkylene glycol ester is improved. As the adsorbent, those having an acid adsorption action, an alkali adsorption action, an acid and an alkali adsorption action are used, and water-insoluble is preferable. In particular, an adsorbent having an acid adsorption ability containing at least one selected from magnesium oxide, aluminum oxide and silicon dioxide, a gas such as carbon dioxide after carbonizing raw materials such as charcoal, peat, coal and coconut shell, or sulfuric acid Activated carbon having fine pores heat-treated with a chemical such as phosphoric acid is preferred. The adsorbent can be added simultaneously with water, or after the treatment with water and before filtering the water-insoluble matter. Moreover, in order to make it easy to filter water-insoluble matter, a filter aid may be used in combination as necessary. Examples of the adsorbent containing one or more selected from magnesium oxide, aluminum oxide, and silicon dioxide include KYOWARD 100, KYOWARD 200, KYODWARD 300, KYOWARD 400, KYODWARD 500, KYODWARD 600S, Commercially available adsorbents such as 1000, KYOWARD 2000 (manufactured by Kyowa Chemical Industry Co., Ltd.) can be used. Examples of commercially available activated carbon include Shirakaba A (manufactured by Takeda Pharmaceutical). Activated carbon has various shapes such as powder, granular, fiber, felt, filter, cartridge, etc. The activated carbon in the form of felt, filter, cartridge is water-insoluble by adding water after the reaction is completed. It can be used as a filter for filtering the minutes. The amount of the adsorbent used is preferably 0.01 to 10% by weight of the total weight of the reaction product after completion of the reaction, more preferably 0, considering the quality improvement effect and economic efficiency of the (meth) acrylic acid polyalkylene glycol ester. 0.05 to 5% by weight. The washing treatment with water or water and an adsorbent can be performed at a so-called normal temperature of about 20 ° C. However, when the viscosity of the object to be treated is high, the treatment can be performed by heating to lower the viscosity. However, the temperature is preferably 100 ° C. or lower in order to prevent side reactions such as hydrolysis and polymerization of the (meth) acrylic acid polyalkylene glycol ester.

  Specific examples of the (meth) acrylic acid polyalkylene glycol ester represented by the formula (a) obtained as described above include methoxypolyethylene glycol mono (meth) acrylate, ethoxypolyethylene glycol mono (meth) acrylate, and propoxy Polyethylene glycol (meth) acrylate, butoxypolyethylene glycol (meth) acrylate, methoxypolyethylene glycol polypropylene glycol (meth) acrylate, hexylalkoxypolyethyleneglycol (meth) acrylate, cyclohexylalkoxypolyethyleneglycol (meth) acrylate, 2-ethylhexyl Alkoxy polyethylene glycol (meth) acrylate, cetyl alkoxy polyethylene glycol (meth) acrylate , Stearylalkoxypolyethyleneglycol (meth) acrylate, methylphenoxypolyethyleneglycol (meth) acrylate, nonylphenoxypolyethyleneglycol (meth) acrylate, decylphenoxypolyethyleneglycol (meth) acrylate, naphthoxypolyethyleneglycol (meth) acrylate, polyethyleneglycolmono (Meth) acrylate, polyethylene glycol polypropylene glycol mono (meth) acrylate, polyethylene glycol polybutylene glycol mono (meth) acrylate and the like.

  The polymer of the (meth) acrylic acid polyoxyalkylene glycol ester represented by the above formula (a) constituting the cement admixture of the present invention is a homopolymer of (meth) acrylic acid polyoxyalkylene glycol ester, Although a copolymer with another monomer may be sufficient, a copolymer is preferable. Examples of other monomers copolymerized with (meth) acrylic acid polyoxyalkylene glycol ester include acrylic acid, methacrylic acid, crotonic acid, acrylate, and methacrylate. Other monomers include unsaturated dicarboxylic acid monomers, (meth) acrylate alkyl monomers, styrene monomers, vinyl ester monomers, unsaturated acrylamides, polyfunctional (meth) acrylates, unsaturated alcohol ethers, ( (Meth) allyl sulfonate and the like can be mentioned, and an unsaturated carboxylic acid monomer represented by the following formula (c) is preferable.

  Examples of the unsaturated carboxylic acid monomer represented by the above formula (c) include acrylic acid, methacrylic acid, crotonic acid, acrylate, and methacrylate. Examples of the acrylate and methacrylate include alkali metal salts such as lithium, potassium and sodium, and alkaline earth metal salts such as calcium and magnesium. Two or more of these unsaturated carboxylic acid monomers can be used in combination. As the unsaturated carboxylic acid monomer, acrylic acid, methacrylic acid, acrylate, and methacrylate are preferable. Further, the cement dispersant of the present invention may be a copolymer of (meth) acrylic acid polyoxyalkylene glycol ester and the above unsaturated carboxylic acid monomer and other monomers copolymerizable therewith. .

  In addition to the water-soluble (meth) acrylic acid polyoxyalkylene glycol ester represented by the above formula (a) and the unsaturated carboxylic acid monomer represented by the above formula (c), another monomer copolymerizable therewith is also copolymerized. When polymerized, the hydrophobicity, hydrophilicity and steric hindrance of the copolymer can be controlled, which is effective for the dispersion performance. Examples of other copolymerizable monomers include (a) unsaturated dicarboxylic acid monomers, (b) esters of polyalkylene glycol and unsaturated dicarboxylic acid, and (c) alkoxyalkylene glycol and unsaturated dicarboxylic acid. Esters, (d) alkyl (meth) acrylate monomers, (e) styrene monomers, (f) vinyl ester monomers, (g) unsaturated acrylamides, (h) polyfunctional (meth) acrylates, (i) ) Unsaturated alcohol ester, (j) (meth) allyl sulfonate and the like. (A) Unsaturated dicarboxylic acid monomers include maleic acid, itaconic acid, citraconic acid, fumaric acid, their metal salts, ammonium salts, organic amine salts, alkyl esters, etc. Itaconic acids, glycol esters thereof, amides with alkylamides, and the like can be mentioned. (D) Examples of the alkyl (meth) acrylate monomer include methyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate, dodecyl methacrylate, and the like. (E) Styrene monomers include styrene, methyl styrene, chlorostyrene, and (f) vinyl ester monomers include vinyl acetate. Examples of (g) unsaturated acrylamides include (meth) acrylamides, and examples of (h) polyfunctional (meth) acrylates include trimethylolpropane di (meth) acrylate. Among the monomers (a) to (j), (a) a maleic acid monomer that is an unsaturated dicarboxylic acid monomer and (j) (meth) allyl sulfonate are preferable. (I) As unsaturated alcohol ether, polyethylene glycol allyl alcohol ether, polyethylene glycol methallyl alcohol ether, polyethylene glycol polypropylene glycol allyl alcohol ether, polyethylene glycol polypropylene glycol methallyl alcohol ether, polypropylene glycol methallyl alcohol ether, methoxypolyethylene glycol allyl Alcohol ethers and the like (j) As the (meth) allyl sulfonate, allyl sulfonate and methallyl sulfonate are preferable. In the case of a copolymer of (meth) acrylic acid polyoxyalkylene glycol ester, an unsaturated carboxylic acid monomer, and other monomers copolymerizable therewith, the proportion of each monomer is (meth) in formula (a). It is preferred to contain at least 10% by weight of acrylic acid polyoxyalkylene glycol ester, more preferably 10 to 95% by weight of (meth) acrylic acid polyoxyalkylene glycol ester of formula (a), 2 to 45% by weight of a saturated carboxylic acid monomer and 50% by weight or less of other monomers (however, except for 0% by weight, the total of the three is 100% by weight), more preferably (meth) acrylic acid poly Oxyalkylene glycol ester 40 to 90% by weight, unsaturated carboxylic acid monomer 10 to 35% by weight, other monomers 0% by weight or less. Generally, the solvent used for the polymerization is water, alcohols such as isopropyl alcohol, hydrocarbons such as cyclohexane and toluene, etc., but the polymer is used for applications such as aqueous dispersants. In this case, it is preferable to perform polymerization using water as a solvent.

  Polymerization of the monomer can be carried out at a temperature of about 30 to 150 ° C. by a known method such as solution polymerization, bulk polymerization or suspension polymerization. Either a continuous method or a batch method can be adopted for the polymerization. In carrying out the polymerization, a polymerization initiator, a reducing agent, a chain transfer agent and the like can be used. As the polymerization initiator, for example, persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate, azo compounds such as azobisisobutyronitrile, peroxides such as benzoyl peroxide, and the like can be used. As the reducing agent, sodium sulfite, sodium bisulfite and the like can be used, and as the chain transfer agent, mercaptopropionic acid and the like can be used. These chemicals such as a polymerization initiator, a reducing agent, and a chain transfer agent can be used alone or in combination of two or more.

  The polymer obtained as described above can be further neutralized with an alkali compound such as an alkali metal hydroxide, an alkaline earth metal hydroxide, an organic amine, or an ammonium salt, if necessary.

  The cement admixture of the present invention preferably has a weight average molecular weight in the range of 1,000 to 500,000, particularly preferably in the range of 5,000 to 100,000. The weight average molecular weight here is a weight average molecular weight in terms of polyethylene glycol as measured by gel permeation chromatography, and is measured under the following conditions.

Weight average molecular weight measuring condition measuring instrument: detector manufactured by JASCO Corporation: differential refractometer eluent: 50 mM NaNO ₃ aqueous solution / acetonitrile = 80/20 (volume%)
Column temperature: 40 ° C
Column: Shodex OHpak SB802.5HQ + SB804HQ + SB806HQ
Reference material: Polyethylene glycol

  The cement composition of the present invention contains water and cement together with the cement admixture. The proportion of the cement admixture in the cement composition is preferably 0.10 to 5.0%, more preferably 0.02 to 2.0%, per 100 parts by weight of cement. Cement is not particularly limited, but examples include various types of cement such as normal Portland cement, early strength cement and other Portland cement, fly ash cement, and cement additions such as blast furnace slag, clinker ash, fly ash, silica fume and gypsum. A material etc. can be used. In addition to the cement admixture, water and cement, the cement composition of the present invention may further contain other cement dispersant, air entraining agent, antifoaming agent, retarder, early strength agent, waterproofing agent, if necessary. It can be used in combination with other cement additives such as thickeners, separation reducing agents, rust preventives, and resin emulsions. Other cement dispersants include copolymers of monomers copolymerizable with (meth) acrylic acid monomers, (alkoxy) polyalkylene glycol (meth) acrylates and (meth) acrylic acid monomers Examples thereof include polycarboxylic acid-based dispersants such as copolymers with isomers, lignin sulfonates, polystyrene sulfonates, melamine sulfonic acid formalin condensates, naphthalene sulfonic acid formalin condensates, amino sulfonic acid dispersants, and the like. Air entrainers include alkyl sulfate salts, polyoxyethylene alkyl sulfate salts, α-olefin sulfonate salts, alkylbenzene sulfonate salts, resin acid soaps, alkane sulfonate salts, fatty acid soaps, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyls Various surfactants such as ether, polyoxyethylene alkylphenyl ether sulfate, polyoxyethylene castor oil ether and the like can be mentioned. Antifoaming agents include fatty acid ester-based antifoaming agents, animal and vegetable oil-based antifoaming agents, mineral oil-based antifoaming agents, alcohol-based antifoaming agents, polyoxyalkylene-based antifoaming agents, silicon-based antifoaming agents, and fatty acid amides. An antifoaming agent etc. are mentioned.

Hereinafter, the present invention will be described in more detail with reference to examples.
Synthesis Example 1: Synthesis of (meth) acrylic acid polyoxyalkylene glycol ether 1 (monomer 1) A 2-liter pressure reactor was charged with 32 g (1 mol) of methanol and 0.5 g of sodium methoxide as a catalyst, and a reaction vessel After sufficiently replacing the interior with nitrogen, 968 g (22 moles) of ethylene oxide was introduced at 100 ° C. to 130 ° C. over 4 hours while maintaining the pressure at 5 kg / cm ² or less to carry out the addition reaction. After completion of the introduction, the reaction was completed by aging for 1 hour. Subsequently, 10 g of KYOWARD 600S (manufactured by Kyowa Chemical Industry Co., Ltd.) was added as an adsorbent at a temperature of 110 to 115 ° C. under introduction of nitrogen, and after an adsorption treatment for 1 hour. Filtration was carried out to obtain methoxypolyethylene glycol to which 22 mol of ethylene oxide was added. Subsequently, 444 g (0.444 mol) of the methoxypolyethylene glycol (average added mole number: 22 mol) was charged into a 2-liter reaction flask equipped with a stirrer, a thermometer, a gas introduction tube, a reflux tube, and a cooling tube. After introducing nitrogen under reduced pressure and heating to 100 to 110 ° C. to dehydrate the water, it was cooled to 50 ° C. and 355 g (3.55 mol) of methyl methacrylate and 1 hydroquinone monomethyl ether as a polymerization inhibitor. .2 g (1500 ppm) and 5 g of tetraisopropyl titanium serving as a transesterification catalyst were added, and the mixture was gradually heated with stirring until distillation of methanol produced as a by-product by the transesterification reaction started. Distillation starts when the reaction temperature in the flask is 100 ° C., and the reaction is carried out while distilling methanol produced as a by-product at the reaction temperature of 100 ° C. to 115 ° C. in the flask. Maintained 65-68 ° C. The reaction was completed in 6 hours. After cooling the reaction product, unreacted methyl methacrylate was distilled off under reduced pressure to obtain 468 g of a crude reaction product. The crude reaction product had a Gardner color of 8 and an acid value of 0.24. After adding 86 g of water (41 times the amount of catalyst used) to 200 g of this reaction product and stirring at 40 ° C. for 1 hour, the mixture was filtered using a filter paper. The water content was 28.8 wt. % Methoxypolyethylene glycol (average added mole number of ethylene oxide 22) methacrylic acid ester was obtained. When the residual amount of titanium derived from the catalyst was quantified, the residual amount of titanium in the crude reaction product was 1374 ppm, and after treatment with water and filtration, it was 2.8 ppm. The acid value was 0.12, the hue was 10 with APHA, and the hydroxyl value was 1.5. The reaction rate was calculated from the hydroxyl value, which was 97.3%. The catalyst-derived titanium residual amount, the catalyst-derived zirconium residual amount (hereinafter simply referred to as titanium residual amount and zirconium residual amount), and the reaction rate were obtained as follows.

Remaining amounts of titanium and zirconium After the reaction product sample was incinerated, the content of titanium and zirconium was measured by a calibration curve method using a standard solution using a plasma emission analyzer using a nitric acid acidic solution.
Measuring device: Plasma emission analyzer ICPS-1000IV (manufactured by Shimadzu Corporation)
Standard solution: Titanium 1000 mg / L standard solution (manufactured by Kanto Chemical Co., Inc.)
Zirconium 1000mg / L standard solution (manufactured by Kanto Chemical Co., Inc.)

Reaction rate The hydroxyl value of the reaction product: OHr (mgKOH) in accordance with the measurement method of the hydroxyl value (pyridine-acetic anhydride method: 2.3.6.2) of the standard oil analysis test method (1996 version) established by the Japan Oil Chemical Association / G) and the hydroxyl value of raw material methoxypolyethylene glycol: OHm (mgKOH / g), and from these values, the content of unreacted alkoxypolyalkylene glycol in the reaction product: A (%) Calculate from the formula (1), and the reaction rate: B (%) is calculated from the value by the following formula (2).
A (%) = OHr ÷ OHm × 100 (1)
B (%) = 100−A (2)

Synthesis Example 2: Synthesis of (Meth) acrylic acid polyoxyalkylene glycol ether 2 (monomer 2) 100 g of methoxypolyethylene glycol methacrylic ester crude reaction product having an average addition mole number of 22 moles of ethylene oxide produced in the same manner as in Synthesis Example 1. After adding 43 g of water (41 times the weight of catalyst used) at 40 ° C. and stirring for 30 minutes, 1 g (crude reaction) of KYOWARD 2000 (manufactured by Kyowa Chemical Industry Co., Ltd.) as an adsorbent was further added. (1% by weight of the product) and stirring at the same temperature for 30 minutes, followed by filtration using filter paper. As a result, methoxypolyethylene glycol having an hue of 10 APHA and a water content of 28.4% by weight (average of ethylene oxide) Addition mole number 22) A methacrylic acid ester is obtained, and the residual amount of titanium of this ester is 0.2 ppm, acid value Was 0.09.

Synthesis Example 3: Synthesis of (meth) acrylic acid polyoxyalkylene glycol ether 3 (monomer 3) A 2-liter reaction flask equipped with a stirrer, thermometer, gas introduction tube, reflux tube, and cooling tube was prepared in the same manner as in Synthesis Example 1. 500 g (0.5 mol) of methoxypolyethylene glycol (average number of added moles of 22 mol) obtained in this manner, 300 g (3 mol) of methyl methacrylate, 0.4 g (500 ppm) of diethylhydroxylamine as a polymerization inhibitor, a transesterification catalyst Then, 2.0 g of tetraisopropyl titanium was added, heating was started gradually with stirring, and the reaction was carried out while distilling off by-produced methanol. The reaction temperature in the flask was 110 ° C. to 122 ° C., and the top temperature of the azeotropic distillate was kept at 60 ° C. to 78 ° C. The reaction was completed in 10 hours, and after cooling the reaction product, unreacted methyl methacrylate was distilled off under reduced pressure to obtain 534 g of a crude reaction product. The crude reaction product had a hue of 150 APHA and an acid value of 0.16. To 200 g of this reaction product, 86 g of water (115 times the amount of catalyst used) was added at 40 ° C. and stirred for 1 hour, and then 2 g of Kyoward 2000 as an adsorbent (1 weight of the crude reaction product). The mixture was stirred at the same temperature for 30 minutes and filtered using a filter paper. The color was 10 APHA, and the moisture content was 30.6% by weight. Methoxypolyethylene glycol (average added mole number of ethylene oxide 22) A methacrylic acid ester was obtained. When the amount of remaining titanium was quantified, the amount of remaining titanium in the crude reaction product was 611 ppm, and the amount after filtration with water and Kyoward 2000 was 0.1 ppm. The acid value of the purified product was 0.08, the hydroxyl value was 0.9, and the reaction rate calculated by the hydroxyl value was 98.4%.

Synthesis Example 4: Synthesis of (meth) acrylic acid polyoxyalkylene glycol ether 4 (monomer 4) A 2-liter pressure reactor was charged with 32 g (1 mol) of methanol and 0.2 g of sodium methoxide as a catalyst, After sufficiently substituting with nitrogen, 440 g (10 mol) of ethylene oxide was introduced at 100 ° C. to 130 ° C. over 3 hours while maintaining a pressure of 5 kg / cm ² or less to carry out an addition reaction. After completion of the introduction, the reaction was terminated by aging for 1 hour, followed by addition of 5 g of KYOWARD 600S (manufactured by Kyowa Chemical Industry Co., Ltd.) as an adsorbent at a temperature of 110 to 115 ° C. under nitrogen introduction for 1 hour. Thereafter, filtration was performed to obtain methoxypolyethylene glycol to which 10 mol of ethylene oxide was added. Subsequently, 472 g (1 mol) of methoxypolyethylene glycol (average mole number of 10 mol) was charged into a 2 liter reaction flask equipped with a stirrer, a thermometer, a gas introduction tube, a reflux tube, and a cooling tube, and 400 g of methyl methacrylate ( 4 mol), 1.74 g (2000 ppm) of hydroquinone monomethyl ether as a polymerization inhibitor, and 4.4 g of tetraisopropyl titanium as a transesterification catalyst, gradually start heating under stirring, and react while distilling off by-product methanol. Went. The reaction temperature in the flask was 105 ° C to 120 ° C, and the top temperature of the azeotropic distillate was kept at 66 ° C to 69 ° C. The reaction was completed in 6 hours. After cooling the reaction product, unreacted methyl methacrylate was distilled off under reduced pressure to obtain 530 g of a crude reaction product. The crude reaction product had a hue of 5 in Gardner color and an acid value of 0.23. The reaction product was cooled to 30 ° C., 10 g of water (6 times the amount of catalyst used) was added to 200 g of the reaction product, and the mixture was stirred for 30 minutes. 2.0 g (1% by weight of the reaction product) was added, stirred at the same temperature for 30 minutes, and filtered using filter paper. The hue was 70 by APHA and the water content was 4.0% by weight. Methoxypolyethylene glycol (average added mole number of ethylene oxide 10) methacrylic acid ester was obtained. When the amount of remaining titanium was quantified, the amount of remaining titanium in the crude reaction product was 1372 ppm, and the amount of remaining titanium was 5.7 ppm after filtration with water and an adsorbent. The acid value was 0.11, the hydroxyl value was 2.9, and the reaction rate calculated by the hydroxyl value was 97.6%.

Synthesis Example 5: Synthesis of (meth) acrylic acid polyoxyalkylene glycol ether 5 (monomer 5) A 2-liter reaction flask equipped with a stirrer, a thermometer, a gas introduction tube, a reflux tube, and a cooling tube was used in the same manner as in Synthesis Example 1. 500 g (0.5 mol) of methoxypolyethylene glycol (average added mole number 22 mol) obtained in this manner, 400 g (4 mol) of methyl methacrylate, 0.45 g (500 ppm) of diethylhydroxylamine as a polymerization inhibitor, transesterification catalyst As described above, 4.5 g of tetranormalpropylzirconium was added, heating was started gradually with stirring, and the reaction was carried out while distilling off by-produced methanol. The reaction temperature in the flask was 113 ° C to 125 ° C, and the top temperature of the azeotropic distillate was kept at 65 ° C to 72 ° C. The reaction was completed in 12 hours. After cooling the reaction product, unreacted methyl methacrylate was distilled off under reduced pressure to obtain 531 g of a crude reaction product. The color of the crude reaction product was 110 by APHA and the acid value was 0.15. After adding 40 g of water (24 times the amount of the catalyst used) to 200 g of this reaction product and stirring for 1 hour, the mixture was filtered using filter paper. A methoxypolyethylene glycol (average added mole number of ethylene oxide 22) methacrylic acid ester having a water content of 16.4% by weight was obtained. When the amount of zirconium remaining was quantified, the amount of zirconium remaining in the crude reaction product was 3360 ppm, and the amount after filtration with water was 1.9 ppm. The acid value of the purified product was 0.08, the hydroxyl value was 1.0, and the reaction rate calculated by the hydroxyl value was 98.2%.

Synthesis Example 6: Synthesis of (Meth) acrylic acid polyoxyalkylene glycol ether 6 (monomer 6) 100 g of methoxypolyethylene glycol methacrylic ester crude reaction product having an average addition mole number of 22 mol of ethylene oxide produced in the same manner as in Synthesis Example 1 1 g of Kyoward 2000 (1% by weight of the crude reaction product) and 1 g of activated clay (1% by weight of the crude reaction product) were added and treated at 100 ° C. for 1 hour. Cellulose filter aid KC-Flock W -50 (manufactured by Nippon Paper Chemical Co., Ltd.) was added in an amount of 1% by weight based on the weight of the crude reaction product, followed by filtration using filter paper. The hue after filtration was 7 in Gardner color, the acid value was 0.23, and the remaining amount of titanium was determined to be 586 ppm.

Synthesis Example 7: Synthesis of (Meth) acrylic acid polyoxyalkylene glycol ether 7 (monomer 7) 100 g of methoxypolyethylene glycol methacrylic ester crude reaction product having an average addition mole number of 22 moles of ethylene oxide produced in the same manner as in Synthesis Example 5 2 g of Kyoward 600S (2% by weight of the crude reaction product) was added to the mixture, treated at 80 ° C. for 1 hour, and the cellulose filter aid KC-Flock W-50 (manufactured by Nippon Paper Chemical Co., Ltd.) was roughly reacted. 0.5% by weight based on the weight of the product was added and filtration was performed using filter paper. The hue after filtration was 60 with APHA, the acid value was 0.16, and the amount of zirconium remaining was determined to be 980 ppm.

Synthesis Example 8: Synthesis of (Meth) acrylic acid polyoxyalkylene glycol ether 8 (monomer 8) Similar to Synthesis Example 4 in a 1-liter reaction flask equipped with a stirrer, thermometer, gas introduction tube, reflux tube, and condenser. 472 g (1 mol) of methoxypolyethylene glycol having an average addition mole number of 10 mol (average addition mole number of 10 moles) of ethylene oxide prepared as described above, 400 g (4 moles) of methyl methacrylate, and 0 hydroquinone monomethyl ether as a polymerization inhibitor .44 g (500 ppm) and 4.4 g of sodium methylate (purity 98%) as a transesterification catalyst were added, heating was started gradually with stirring, and the reaction was carried out while distilling off by-produced methanol. Distillation started from a reaction temperature of 101 ° C. in the flask, and the reaction was carried out while removing the azeotropic distillate. The reaction temperature in the flask increased so rapidly that the temperature in the flask reached 126 ° C. after 1 hour. did. The reaction was completed in 6 hours, and after cooling the reaction product, unreacted methyl methacrylate was distilled off under reduced pressure to obtain 525 g of a crude reaction product. 67 g of water (40 times the amount of catalyst used) was added to 200 g of this reaction product and stirred for 30 minutes, followed by filtration using filter paper. As a result, the hue was 6 in Gardner color and the water content was 24. 8% by weight of methoxypolyethylene glycol (average added mole number of ethylene oxide 10) methacrylic acid ester was obtained. When the sodium derived from the catalyst was quantified by atomic absorption spectrometry, the amount of sodium in the crude reaction product before water treatment was 3390 ppm, and after treatment with water, filtered was 2324 ppm, and sodium derived from the catalyst was It was not removed. When the hydroxyl value of the treated product having a water content of 24.8% by weight was measured, 11.3% of unreacted methoxypolyethylene glycol (average number of moles added: 10 mol) remained at 11.3% in the treated product. The reaction rate was 85.1%.

Synthesis Example 9: Synthesis of water-soluble (meth) acrylic acid polyoxyalkylene glycol ether 9 (monomer 9) Synthesis Example 1 in a 1-liter reaction flask equipped with a stirrer, a thermometer, a gas introduction tube, a reflux tube, and a cooling tube 500 g (0.5 mol) of methoxypolyethylene glycol having an average addition mole number of 22 moles of ethylene oxide (average addition mole number of 22 moles) prepared in the same manner as above, 300 g (3 moles) of methyl methacrylate, and diethyl as a polymerization inhibitor 0.4 g (500 ppm) of hydroxylamine and 2 g of sodium methylate (purity 98%) as a transesterification catalyst were added, and the reaction was carried out while distilling off by-produced methanol, which was gradually heated under stirring. Distillation started at a reaction temperature of 110 ° C in the flask, and when the reaction was carried out, the reaction temperature in the flask increased rapidly, and after 1 hour and 30 minutes, the temperature in the flask reached 130 ° C and the distillation of methanol stopped. The reaction was terminated. After the reaction product was cooled, unreacted methyl methacrylate was distilled off under reduced pressure, and the reaction product was taken out. When 200 g of this reaction product was added with 85 g of water (115 times the amount of catalyst used) at 40 ° C. and filtered, it was a slightly cloudy liquid with a water content of 29.2 wt%. When the hydroxyl value of the treated product having a water content of 29.2% by weight was measured, it showed a gel during measurement and could not be measured.

Example 1
A glass reaction vessel equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser was charged with 399 g of ion-exchanged water, and the reaction vessel was purged with nitrogen under stirring and heated to about 100 ° C. in a nitrogen atmosphere. Next, 355 g of monomer 1 produced in Synthesis Example 1, 52 g of methacrylic acid, 94 g of ion-exchanged water, an aqueous monomer solution consisting of 0.5 g of sodium hydroxide, and an initiator consisting of 100 g of 4.5% aqueous sodium persulfate solution Two solutions of the aqueous solution were dropped over 2 hours using a metering pump. After maintaining at 100 ° C. for 1 hour, the mixture was cooled to 35 ° C. and partially neutralized with 10 g of a 30% aqueous sodium hydroxide solution to obtain a polymer having a solid content of 30.0% and a weight average molecular weight of 30700.

Example 2
A glass reaction vessel equipped with a thermometer, a stirrer, a nitrogen introduction tube, and a reflux condenser was charged with 350 g of ion exchange water, and the reaction vessel was purged with nitrogen under stirring, and heated to about 100 ° C. in a nitrogen atmosphere. Next, 220 g of the monomer 2 produced in Synthesis Example 2, 44 g of the monomer 4 produced in Synthesis Example 4, 93 g of methacrylic acid, 199 g of ion-exchanged water, 3 g of 31% sodium hydroxide, 4 g of excess monomer solution Two solutions of an initiator aqueous solution consisting of 65 g of an aqueous initiator solution in which sodium sulfate was dissolved in 61 g of ion-exchanged water were dropped over 2 hours using a metering pump. After maintaining at 100 ° C. for 1 hour, the mixture was cooled to 35 ° C. and partially neutralized with 17 g of 31% aqueous sodium hydroxide solution to obtain a polymer having a solid content of 29.4% and a weight average molecular weight of 30200.

Example 3
A glass reaction vessel equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser was charged with 399 g of ion-exchanged water, and the reaction vessel was purged with nitrogen under stirring and heated to about 100 ° C. in a nitrogen atmosphere. Next, an initiator comprising 303 g of monomer 1 produced in Synthesis Example 1, 88 g of methacrylic acid, 110 g of ion-exchanged water, 0.8 g of sodium hydroxide, and 100 g of a 4.5% sodium persulfate aqueous solution. Two solutions of the aqueous solution were dropped over 2 hours using a metering pump. After maintaining at 100 ° C. for 1 hour, the mixture was cooled to 35 ° C. and partially neutralized with 17 g of a 30% aqueous sodium hydroxide solution to obtain a polymer having a solid content of 30.0% and a weight average molecular weight of 25600.

Example 4
A glass reaction vessel equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser was charged with 390 g of ion-exchanged water, and the reaction vessel was purged with nitrogen under stirring and heated to about 100 ° C. in a nitrogen atmosphere. Next, an initiator composed of 218 g of monomer 4 produced in Synthesis Example 4, 91 g of methacrylic acid, 201 g of ion-exchanged water, 0.8 g of sodium hydroxide, and 100 g of 4.5% sodium persulfate aqueous solution. Two solutions of the aqueous solution were dropped over 2 hours using a metering pump. After maintaining at 100 ° C. for 1 hour, the mixture was cooled to 35 ° C. and partially neutralized with 17.4 g of a 30% aqueous sodium hydroxide solution to obtain a polymer having a solid content of 30.8% and a weight average molecular weight of 30400.

Example 5
A glass reaction vessel equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser was charged with 399 g of ion-exchanged water, and the reaction vessel was purged with nitrogen under stirring and heated to about 100 ° C. in a nitrogen atmosphere. Next, an initiator comprising 303 g of the monomer 5 produced in Synthesis Example 5, 88 g of methacrylic acid, 110 g of ion-exchanged water, 0.8 g of sodium hydroxide, and 100 g of a 4.5% sodium persulfate aqueous solution. Two solutions of the aqueous solution were dropped over 2 hours using a metering pump. After maintaining at 100 ° C. for 1 hour, the mixture was cooled to 35 ° C. and partially neutralized with 17 g of a 30% aqueous sodium hydroxide solution to obtain a polymer having a solid content of 29.3% and a weight average molecular weight of 28600.

Example 6
A glass reaction vessel equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser was charged with 399 g of ion-exchanged water, and the reaction vessel was purged with nitrogen under stirring and heated to about 100 ° C. in a nitrogen atmosphere. Next, 303 g of the monomer 5 produced in Synthesis Example 5, 58 g of methacrylic acid, 30 g of sodium methallyl sulfonate, 110 g of ion-exchanged water, 0.8 g of sodium hydroxide, 4.5% persulfuric acid Two solutions of an initiator aqueous solution consisting of 100 g of an aqueous sodium solution were added dropwise over 2 hours using a metering pump. After maintaining at 100 ° C. for 1 hour, the mixture was cooled to 35 ° C. and partially neutralized with 17 g of a 30% aqueous sodium hydroxide solution to obtain a polymer having a solid content of 29.5% and a weight average molecular weight of 21,300.

Example 7
A glass reaction vessel equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser was charged with 436 g of ion-exchanged water, and the reaction vessel was purged with nitrogen under stirring and heated to about 100 ° C. in a nitrogen atmosphere. Next, an initiator comprising 318 g of the monomer 3 produced in Synthesis Example 3, 52 g of methacrylic acid, 94 g of ion-exchanged water, 0.5 g of sodium hydroxide, and 100 g of a 4.5% sodium persulfate aqueous solution. Two solutions of the aqueous solution were dropped over 2 hours using a metering pump. After maintaining at 100 ° C. for 1 hour, the mixture was cooled to 35 ° C. and partially neutralized with 10 g of a 30% aqueous sodium hydroxide solution to obtain a polymer having a solid content of 30.1% and a weight average molecular weight of 30700.

Example 8
A glass reaction vessel equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser was charged with 397 g of ion exchange water, and the inside of the reaction vessel was purged with nitrogen under stirring, and heated to about 100 ° C. in a nitrogen atmosphere. Next, an initiator comprising 161 g of monomer 1 produced in Synthesis Example 1, 187 g of methacrylic acid, 153 g of ion-exchange water, 1.7 g of sodium hydroxide, and 100 g of a 4.5% sodium persulfate aqueous solution. Two solutions of the aqueous solution were dropped over 2 hours using a metering pump. After maintaining at 100 ° C. for 1 hour, the mixture was cooled to 35 ° C. and partially neutralized with 108 g of a 30% aqueous sodium hydroxide solution to obtain a polymer having a solid content of 28.6% and a weight average molecular weight of 34200.

Example 9
A glass reaction vessel equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser was charged with 391 g of ion-exchanged water, and the reaction vessel was purged with nitrogen under stirring and heated to about 100 ° C. in a nitrogen atmosphere. Next, an initiator comprising 161 g of monomer 4 produced in Synthesis Example 4, 139 g of methacrylic acid, 201 g of ion-exchanged water, 1.3 g of sodium hydroxide, and 100 g of a 4.5% sodium persulfate aqueous solution. Two solutions of the aqueous solution were dropped over 2 hours using a metering pump. After maintaining at 100 ° C. for 1 hour, the mixture was cooled to 35 ° C. and partially neutralized with 27 g of a 30% aqueous sodium hydroxide solution to obtain a polymer having a solid content of 29.9% and a weight average molecular weight of 31200.

Comparative Example 1
Polymerization was carried out in the same manner as in Example 9 using the monomer 8 produced in Synthesis Example 8, and a polymer having a solid content of 29.9% and a weight average molecular weight of 11,500 was obtained.

Comparative Example 2
Polymerization was carried out in the same manner as in Example 6 using the monomer 6 produced in Synthesis Example 6 to obtain a polymer having a solid content of 30.1% and a weight average molecular weight of 9900.

Comparative Example 3
Polymerization was carried out in the same manner as in Example 6 using the monomer 7 produced in Synthesis Example 7 to obtain a polymer having a solid content of 30.1% and a weight average molecular weight of 12800.

Comparative Example 4
Polymerization was carried out in the same manner as in Example 6 using the monomer 9 produced in Synthesis Example 9, but gelation occurred during polymerization, and no polymer was obtained.

  In order to evaluate cement dispersibility using the polymers obtained in Examples 1 to 9 and Comparative Examples 1 to 4, the following mortar tests were performed.

Test material: Cement Ordinary Portland cement (Pacific cement)
Sand Standard sand for cement strength test (Cement Association)
Tap water Mortar preparation method: Mortar was prepared with the following composition according to JIS R 5201-1997.
200g of tap water
Cement 540g
1350g of sand
W / C = 37% s / c = 2.5
Kneading machine: Shinagawa universal kneading machine (50 Mr)

  A specified amount of tap water in which the polymer obtained in Examples 1 to 9 and Comparative Examples 1 to 3 and an antifoaming agent (Trimin DF-325; manufactured by Miyoshi Oil and Fats) are dispersed is put into a kneading bowl, and then cement is added. Immediately after the addition, the kneader was started at a low speed (spinning speed: 140 ± 5 revolutions per minute, revolution speed; 140 ± 5 revolutions per minute). Thirty seconds after starting the paddle, a specified amount of sand was added in 30 seconds and continued to knead for 60 seconds, then the kneading was paused for 60 seconds and scraped off for the first 15 seconds of rest. When the pause is over, start at a high speed (automatic rotation speed: 285 ± 5 revolutions per minute, revolution speed: 125 ± 5 revolutions per minute) and knead for 60 seconds. A mortar was prepared by swirling. The amount of air immediately after kneading was measured with a mortar air meter. Moreover, the slump and flow value of mortar were measured by the following methods. These results are shown in Table 1. Moreover, the addition amount (converted value of solid substance) of a polymer is also shown in Table 1.

Slump, flow value measuring method: The slump measurement of the prepared mortar was performed immediately after 60 minutes according to JIS A 1101 using the following slump cone. Moreover, the longest part and the shortest part of the diameter of the mortar were measured after the slump measurement, and the average value was used as the flow value.
Slump cone: Mortar slump cone (Maruto Seisakusho)
Upper diameter 50mm Lower diameter 100mm Height 150mm

Claims (7)

The following formula was obtained by subjecting a glycol compound and (meth) acrylic acid ester to a transesterification reaction using titanium alkoxide and / or zirconium alkoxide as a transesterification catalyst, and then treating with water to separate and remove insoluble matter. A cement admixture comprising a water-soluble (meth) acrylic acid polyoxyalkylene glycol ester polymer represented by (a).

The cement admixture according to claim 1, wherein the glycol compound is a compound represented by the following formula (b) containing 20% by weight or more of an ethylene oxide component.

The cement admixture according to claim 1 or 2, comprising a copolymer of a water-soluble (meth) acrylic acid polyoxyalkylene glycol ester and another monomer. The cement admixture according to claim 3, which is a copolymer of a water-soluble (meth) acrylic acid polyoxyalkylene glycol ester and an unsaturated carboxylic acid monomer represented by the following formula (c).

4. A copolymer of a water-soluble (meth) acrylic acid polyoxyalkylene glycol ester, an unsaturated carboxylic acid monomer represented by the following formula (c), and other monomers copolymerizable therewith. Cement admixture.

10-95% by weight of water-soluble (meth) acrylic acid polyoxyalkylene glycol ester, 2-45% by weight of unsaturated carboxylic acid monomer, and 50% by weight or less of other monomers copolymerizable therewith (however, 0% by weight) The cement admixture according to claim 5, wherein the total of the three components is 100% by weight. A cement composition comprising the cement admixture according to claim 1, water and cement.