JPH1171151A - Production of ester for producing cement admixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the productivity of a polyalkylene glycol (meth)acrylate without causing a get, by using a polyalkylene glycol having a peroxide value equal to or smaller than a specific value and a (meth)acrylic acid-based monomer as raw materials and carrying out esterification. SOLUTION: A polyalkylene glycol having <=0.7 meq/kg peroxide value is used. The polyalkylene is shown by the formula HO(R<1> O)n R<2> (R<1> O is one or a mixture of oxyalkylene groups and in the case of two or more, R<1> O may be added in a block or random state; R<2> is a 1-22C alkyl, phenyl or an alkylphenyl; (n) is 1-300). Preferably there is a relation of the equation (a/n<1/2> )/b}×100<=200 among the pts.wt. (a) of the polyalkylene glycol to be added to a reactor, the pts.wt. (b) of the (meth)acrylic acid-based monomer and the average number (n) of addition mols of the oxyalkylene group contained in the polyalkylene glycol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an ester used as an intermediate in producing a cement admixture.

[0002]

2. Description of the Related Art In the concrete industry in recent years, there is a strong demand for improvements in the durability and strength of concrete buildings. Improvements have been made by increasing the dispersibility of cement in cement compositions used for the production of concrete buildings. Is known to be. In the concrete industry, it takes time from the preparation of a cement composition to its use. For this reason, cement compositions are also required to have high slump retention.

As a cement admixture for improving the cement dispersibility and the slump retention, there is an admixture containing a polycarboxylic acid.

[0004]

According to the study of the present inventors, this polycarboxylic acid is obtained by reacting a polyalkylene glycol with a (meth) acrylic acid monomer to form a polyalkylene glycol (meth) acrylate. It can be produced through an esterification step obtained, and a polymerization step of reacting the obtained polyalkylene glycol (meth) acrylate with the (meth) acrylic acid-based monomer to obtain a polycarboxylic acid. In the formation step, a gel was generated, and it was necessary to perform filtration and the like in order to remove the gel.

Accordingly, an object of the present invention is to provide a method for producing an ester for producing a cement admixture, which can produce a polyalkylene glycol (meth) acrylate with high productivity without generating a gel.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, if the peroxide value of the polyalkylene glycol used as a raw material for esterification is below a certain value, the above-mentioned problems will be solved. Finds a solution,
The present invention has been completed. That is, the method for producing an ester for producing a cement admixture according to the present invention is a method for producing a polyalkylene glycol (meth) acrylate by performing esterification using a polyalkylene glycol and a (meth) acrylic acid-based monomer as raw materials. The polyalkylene glycol has a peroxide value of 0.7
It is characterized by using a polyalkylene glycol having a meq / kg or less.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing an ester according to the present invention is a method of esterifying a polyalkylene glycol (A) and a (meth) acrylic acid monomer (B) as raw materials. As a product, polyalkylene glycol (meth) acrylate (C) is obtained.

The polyalkylene glycol (A) is represented by the following general formula (1).

[0009]

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(However, in the formula, R ¹ O represents one or a mixture of two or more oxyalkylene groups, and in the case of two or more, they may be added in block form or in random form. , R ² is an alkyl group having 1 to 22 carbon atoms, a phenyl group, an alkyl phenyl group, n represents the number of 1 to 300 the average molar number of addition of oxyalkylene group.) as the polyalkylene glycol (a) Is, for example, methoxy (poly) ethylene glycol, methoxy (poly) ethylene glycol (poly) propylene glycol, methoxy (poly) propylene glycol, methoxy (poly)
Ethylene glycol (poly) butylene glycol, methoxy (poly) ethylene glycol (poly) propylene glycol (poly) butylene glycol, methoxy (poly) butylene glycol, ethoxy (poly) ethylene glycol, ethoxy (poly) ethylene glycol (poly) propylene glycol , Ethoxy (poly) propylene glycol, ethoxy (poly) ethylene glycol (poly) butylene glycol, ethoxy (poly) ethylene glycol (poly) propylene glycol (poly) butylene glycol, ethoxy (poly) butylene glycol, phenoxy (poly) ethylene glycol , Phenoxy (poly) ethylene glycol (poly) propylene glycol, phenoxy (poly) propylene glycol, phenoxy (poly) ethylene glycol (Poly) butylene glycol, phenoxy (poly) ethylene glycol (poly) propylene glycol (poly) butylene glycol, phenoxy (poly) butylene glycol, alkyl phenoxy (poly) ethylene glycol, alkyl phenoxy (poly) ethylene glycol (poly) Propylene glycol, alkyl phenoxy (poly) propylene glycol, alkyl phenoxy (poly) ethylene glycol (poly) butylene glycol, alkyl phenoxy (poly) ethylene glycol (poly) propylene glycol (poly) butylene glycol, alkyl phenoxy (poly) butylene glycol, And the like, and one or more of these can be used.
Among these, those containing many ethylene glycol chains, such as methoxy (poly) ethylene glycol, are particularly preferable.

The average number of moles of the added oxyalkylene group is
1 to 300, preferably 10 to 250, more preferably 20 to 200. When R ² is an alkyl group, it has 1 to 22 carbon atoms, preferably 1 to 1 carbon atom.
0, more preferably 1 to 5. The peroxide value of the polyalkylene glycol (A) used in the production method of the present invention is 0.7 meq / kg or less, preferably 0.5 meq / kg or less, more preferably 0.3 meq / kg or less.
q / kg or less. Peroxide value 0.7 meq / kg
In the case of exceeding, a gel is generated and a removing step by filtration is required. Further, when the obtained polyalkylene glycol (meth) acrylate (C) is copolymerized with a (meth) acrylic acid-based monomer (B) described later, abnormal molecular weight distribution, generation of gel, or gelation occurs. Be able to be seen. As a result, the cement dispersing performance or slump holding performance of the polycarboxylic acid obtained by copolymerization is greatly reduced.

The (meth) acrylic acid monomer (B) is represented by the following general formula (2).

[0013]

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(Wherein R ³ represents hydrogen or a methyl group.) The (meth) acrylic acid monomer (B) includes, for example, acrylic acid, methacrylic acid and their monovalent metal salts,
Examples thereof include a valent metal salt, an organic amine salt, and an ammonium salt, and one or two of these may be used.
In the production method of the present invention, a part by weight of the polyalkylene glycol (A), b parts by weight of the (meth) acrylic acid-based monomer (B), and an oxyalkylene group contained in the polyalkylene glycol (A) are charged into the reactor. It is preferable that the relationship of {(a / n ^1/2 ) / b} × 100 ≦ 200 is satisfied between the average number of added moles n.

Here, {(a / n ^1/2 ) / b} × 100
(Hereinafter may be referred to as “K value”) is a scale representing the number of polyalkylene glycol (A) per weight of carboxylic acid, and more preferably 40 ≦ K value ≦ 2.
00, more preferably 42 ≦ K value ≦ 190, and most preferably 45 ≦ K value ≦ 160. Further, from the viewpoint of shortening the esterification reaction time, it is preferable to charge the polyalkylene glycol (A) and the (meth) acrylic acid-based monomer (B) within the range of the above K value, and the productivity is greatly improved. Be improved. When the K value exceeds 200, the esterification reaction time is significantly increased, and the productivity is significantly reduced, which is not preferable.

In the above esterification, the conversion of the polyalkylene glycol (A) is not necessarily required to be 100% from the viewpoint of performance, but is preferably at least 90%, more preferably at least 95%, more preferably at least 95%. 98
% Or more. The esterification reaction is not particularly limited, and can be performed by a known method using a known catalyst, a polymerization inhibitor, and, if necessary, a known solvent.

As the catalyst used in the esterification reaction, known catalysts can be widely used. Examples of such a catalyst include sulfuric acid, paratoluenesulfonic acid, methanesulfonic acid, and the like, and one or more of these can be used. As the polymerization inhibitor used in the esterification reaction, known ones can be widely used. Examples of such polymerization inhibitors include quinones such as hydroquinone and methoquinone; cupron; phenothiazine; and the like, and one or more of these can be used.

The esterification reaction can be carried out under reduced pressure or normal pressure, and can be carried out in the presence or absence of a solvent. It is preferable to use a solvent which can azeotrope with water from the viewpoint of distilling water generated by the esterification reaction out of the reactor. When the esterification reaction is carried out in the absence of a solvent, nitrogen or helium is not used. Activated gas can be passed through the reactor to drive off the product water. Examples of such a solvent include aromatics such as benzene, toluene, and xylene; alicyclic compounds such as cyclohexane; aliphatic hydrocarbons such as n-hexane; Alternatively, two or more kinds can be used.

The polyalkylene glycol (meth) acrylate (C) thus obtained has a structure represented by the following general formula (3).

[0020]

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(Wherein R ³ represents hydrogen or a methyl group, R ¹ O represents ^one or a mixture of two or more oxyalkylene groups, and in the case of two or more, they are added in a block form. May also be added at random, R ² represents an alkyl group having 1 to 22 carbon atoms, a phenyl group, an alkylphenyl group, n is the average number of added moles of the oxyalkylene group, The polyalkylene glycol (meth) acrylate (C) obtained by the production method of the present invention can be copolymerized with a (meth) acrylic acid monomer (B) to obtain a polycarboxylic acid. This polycarboxylic acid is used as an active ingredient of a cement admixture as described later.

The copolymerization may be carried out by adding a copolymerizable monomer (D) as described below to the reaction system for the copolymerization. The polyalkylene glycol (meth) acrylates (C) and (meth) A monomer mixture (I) containing an acrylic acid-based monomer (B) as an essential component and sometimes containing a copolymerizable monomer (D) described below may be used for the copolymerization.

The reaction mixture containing the polyalkylene glycol (meth) acrylate (C) obtained by the copolymerization is as follows:
Since it also contains a (meth) acrylic acid-based monomer (B), it can be used as it is as a monomer mixture (I) for copolymerization, and the productivity of the target polycarboxylic acid is greatly improved. You. When the esterification reaction is carried out in the presence of a solvent, the solvent may be distilled off, and then the aqueous monomer mixture (I) may be used for copolymerization.

As the monomer mixture (I), a mixture obtained by further adding a copolymerizable monomer to the above reaction mixture may be used. Examples of the copolymerizable monomer include a (meth) acrylic acid-based monomer (B) and / or a copolymerizable monomer (D). Especially, it is preferable to add a (meth) acrylic acid monomer (B). Examples of the copolymerizable monomer (D) include maleic acid, fumaric acid, itaconic acid, citraconic acid, and unsaturated dicarboxylic acids such as monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts thereof. Acids or anhydrides thereof; half esters and diesters of the unsaturated dicarboxylic acids and alcohols having 1 to 22 carbon atoms; half amides of the unsaturated dicarboxylic acids and amines having 1 to 22 carbon atoms;
Diamides; these alcohols and amines have 2 to 4 carbon atoms
Half-esters and diesters of alkylpolyalkylene glycols to which 1 to 300 moles of oxyalkylenes have been added and the unsaturated dicarboxylic acids; glycols having 2 to 4 carbon atoms of the unsaturated dicarboxylic acids or addition moles of these glycols of 2 Half-esters and diesters with polyalkylene glycols having a molecular weight of 300 to 300; half-amides of maleamic acid with glycols having 2 to 4 carbon atoms or polyalkylene glycols having an addition mole number of 2 to 300 of these glycols; (Poly) alkylene such as acrylate, (poly) ethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, (poly) ethylene glycol (poly) propylene glycol di (meth) acrylate Chole di (meth) acrylates (hereinafter sometimes referred to as polyalkylene glycol di (meth) acrylate (E)); hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane di (meth) ) Bifunctional (meth) acrylates such as acrylate; (poly) alkylene glycol dimaleates such as triethylene glycol dimaleate and polyethylene glycol dimaleate; vinyl sulfonate, (meth) allyl sulfonate, 2- (meth) acryloxyethyl Sulfonate, 3- (meth) acryloxypropylsulfonate, 3- (meth) acryloxy-2-hydroxypropylsulfonate, 3- (meth) acryloxy-2-
Hydroxypropylsulfophenyl ether, 3- (meth) acryloxy-2-hydroxypropyloxysulfobenzoate, 4- (meth) acryloxybutylsulfonate, (meth) acrylamidomethylsulfonic acid,
Unsaturated sulfonic acids such as (meth) acrylamidoethylsulfonic acid, 2-methylpropanesulfonic acid (meth) acrylamide and styrenesulfonic acid, and their monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts; Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
(Meth) acrylic acid such as 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, methyl crotonate, and glycidyl (meth) acrylate, having 1 to 22 carbon atoms
With an alcohol; unsaturated monocarboxylic acids such as methyl (meth) acrylamide and C 1-2
Amides with two amines; vinyl aromatics such as styrene, α-methylstyrene, vinyltoluene and p-methylstyrene; 1,4-butanediol mono (meth) acrylate, 1,5-pentanediol mono ( Alkanediol mono (meth) acrylates such as meth) acrylate and 1,6-hexanediol mono (meth) acrylate; butadiene, isoprene, 2-methyl-1,3
-Dienes such as butadiene and 2-chloro-1,3-butadiene; unsaturated such as (meth) acrylamide, (meth) acrylalkylamide, N-methylol (meth) acrylamide and N, N-dimethyl (meth) acrylamide Amides; unsaturated cyanates such as (meth) acrylonitrile and α-chloroacrylonitrile; vinyl acetate;
Unsaturated esters such as vinyl propionate; (meth)
Unsaturated amines such as aminoethyl acrylate, methylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dibutylaminoethyl (meth) acrylate, and vinylpyridine; Divinyl aromatics such as divinylbenzene; cyanurates such as triallyl cyanurate; (meth) allyl alcohol, glycidyl (meth)
Allyls such as allyl ether; unsaturated amino compounds such as dimethylaminoethyl (meth) acrylate; methoxypolyethylene glycol monovinyl ether, polyethylene glycol monovinyl ether, methoxypolyethylene glycol mono (meth) allyl ether, polyethylene glycol mono (meth) allyl Vinyl ether or allyl ether such as ether; polydimethylsiloxane propylaminomaleamic acid, polydimethylsiloxane aminopropyleneaminomaleamic acid, polydimethylsiloxane-bis- (propylaminomaleamic acid), polydimethylsiloxane-bis- ( Dipropyleneaminomaleamic acid), polydimethylsiloxane- (1-propyl-3-acrylate), polydimethylsiloxane Hexane - (1-propyl-3
Methacrylate), polydimethylsiloxane-bis-
Siloxane derivatives such as (1-propyl-3-acrylate) and polydimethylsiloxane-bis- (1-propyl-3-methacrylate); and one or more of these can be used. .
The monomer mixture (I) contains a polyalkylene glycol di (meth) acrylate (E) represented by the following general formula (4) as an impurity contained in the reaction system for performing the copolymerization. , But the content is preferably 0 to 5% by weight, more preferably 1% by weight, based on the polyalkylene glycol (meth) acrylate (C).
Less than 0.1% by weight, most preferably 0% by weight. When the amount of the polyalkylene glycol di (meth) acrylate exceeds 5% by weight, an abnormal molecular weight distribution and an abnormal high molecular weight occur during polymerization. As a result, the cement dispersing performance or slump holding performance of the obtained polycarboxylic acid is greatly reduced.

[0025]

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(Wherein R ⁴ and R ⁶ each independently represent hydrogen or a methyl group; R ⁵ O represents one or a mixture of two or more oxyalkylene groups; May be added in a random or random manner, and r is the average number of moles of the oxyalkylene group and represents a number of 1 to 300.) The polymerization method of the monomer mixture (I) is as follows. There is no particular limitation, and a known polymerization method such as solution polymerization or bulk polymerization using a polymerization initiator can be employed.

The polymerization can be carried out in a batch system or a continuous system. In this case, the solvent used if necessary can be a known solvent and is not particularly limited. Examples of such a solvent include water; alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; benzene, toluene, xylene, cyclohexane,
aromatic or aliphatic hydrocarbons such as n-heptane;
Esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone; and the like, but from the solubility of the monomer mixture and the resulting polycarboxylic acid, a group consisting of water and a lower alcohol having 1 to 4 carbon atoms. It is preferable to use one kind or two or more kinds selected from

As the polymerization initiator, known ones can be used and are not particularly limited. As such a polymerization initiator,
For example, persulfates such as ammonium persulfate, sodium persulfate and potassium persulfate; hydrogen peroxide; azo compounds such as azobis-2-methylpropionamidine hydrochloride and azoisobutyronitrile; benzoyl peroxide, lauroyl peroxide, cumene hydro Peroxides such as peroxides; and one or more of these can be used. At this time, a reducing agent such as sodium bisulfite, sodium sulfite, Mohr's salt, sodium pyrobisulfite, sodium formaldehyde sulfoxylate, ascorbic acid or the like as an accelerator;
One or more of amine compounds such as ethylenediamine, sodium ethylenediaminetetraacetate, and glycine; and the like may be used in combination.

A chain transfer agent can be used if necessary. As the chain transfer agent, known compounds can be used and are not particularly limited. For example, mercaptopropionic acid, 2-ethylhexyl mercaptopropionate, octanoic acid 2
-Mercaptoethyl ester, 1,8-dimercapto-
3,6-dioxaoctane, decanetrithiol, dodecylmercaptan, hexadecanethiol, decanethiol, carbon tetrachloride, carbon tetrabromide, α-methylstyrene dimer, terpinolene, α-terpinene, γ-terpinene, dipentene, 2-pentene Examples thereof include aminopropan-1-ol, and one or more of these can be used.

The polymerization temperature depends on the polymerization method used, the solvent,
Although it is appropriately determined depending on the polymerization initiator and the chain transfer agent, it is usually carried out within the range of 0 to 150 ° C. The polycarboxylic acid obtained in this manner is excellent in cement dispersing performance, has high slump retention performance, and is used as it is as a main component of the cement admixture. May be used after neutralization. Preferred examples of such an alkaline substance include inorganic salts such as hydroxides, chlorides and carbonates of monovalent and divalent metals; ammonia; and organic amines.

The polycarboxylic acid is a polymer having a main chain and a side chain, and the main chain is a structural portion derived from the (meth) acrylic acid monomer (B) and / or a salt thereof, The side chain is a structural portion derived from the polyalkylene glycol (A). The main chain and the side chain are linked via an ester bond and / or an ether bond.

The molecular weight of the polycarboxylic acid may be in a wide range, for example, 500 to 1,000,000, preferably 5,000 to 500,000, more preferably 10,000 to 100,000, more preferably 15,
000 to 50,000. The cement admixture contains the polycarboxylic acid obtained above as an active ingredient.

This cement admixture may contain a known cement admixture component in addition to the above polycarboxylic acid. Such known cement admixture components include, for example, cement dispersants, air entrainers, cement wetting agents,
Expansive material, waterproofing agent, retarder, quick-setting agent, water-soluble polymer,
Examples include a thickener, a coagulant, a drying shrinkage reducing agent, a strength enhancer, a curing accelerator, and an antifoaming agent.

Examples of the cement dispersant include lignin sulfonate; oxycarboxylate; polyol derivative; naphthalenesulfonic acid formalin condensate; melaminesulfonic acid formalin condensate;
Aminosulfonic acids such as aminoarylsulfonic acid-phenol-formaldehyde condensates as in No. 9; polyalkylene glycol mono (meth) acrylate compounds and (meth) acrylic as component (a) as in JP-A-7-267705 A copolymer with an acid compound and / or a salt thereof; a copolymer of a polyalkylene glycol mono (meth) allyl ether compound with maleic anhydride as a component (b) and / or a hydrolyzate thereof and / or Salt, a dispersant for cement comprising a copolymer of a polyalkylene glycol mono (meth) allyl ether compound and a maleic acid ester of a polyalkylene glycol compound as a component (c) and / or a salt thereof, Patent Document 2
No. 508113, a copolymer of a polyalkylene glycol ester of (meth) acrylic acid and (meth) acrylic acid (salt) as an A component, a specific polyethylene glycol polypropylene glycol compound as a B component, C
Concrete admixture comprising a specific surfactant as a component, polyethylene (propylene) glycol ester of (meth) acrylic acid or polyethylene (propylene) glycol mono (meth) allyl ether, (meth) allyl as disclosed in JP-A-62-216950 A copolymer comprising sulfonic acid (salt) and (meth) acrylic acid (salt),
As disclosed in Japanese Patent Application Laid-Open No. 1-222657, a copolymer composed of polyethylene (propylene) glycol ester of (meth) acrylic acid, (meth) allylsulfonic acid (salt), and (meth) acrylic acid (salt) is disclosed in Japanese Patent Publication No. 5-36377. As described above, polyethylene (propylene) glycol ester of (meth) acrylic acid, (meth) allylsulfonic acid (salt) or p- (meth) allyloxybenzenesulfonic acid (salt), and a copolymer comprising (meth) acrylic acid (salt) Coalescing,
Copolymer of polyethylene glycol mono (meth) allyl ether and maleic acid (salt) as disclosed in JP-A-4-14956, polyethylene glycol ester of (meth) acrylic acid as disclosed in JP-A-5-170501, (meth) allylsulfonic acid Copolymer consisting of (salt), (meth) acrylic acid (salt), alkanediol mono (meth) acrylate, polyalkylene glycol mono (meth) acrylate, α, β-unsaturated monomer having an amide group in the molecule Coalescing,
As disclosed in JP-A-6-191918, polyethylene glycol mono (meth) allyl ether, polyethylene glycol mono (meth) acrylate, alkyl (meth) acrylate, (meth) acrylic acid (salt), (meth) allyl sulfonic acid (salt) Alternatively, a copolymer comprising p- (meth) allyloxybenzenesulfonic acid (salt),
43288, a copolymer of alkoxypolyalkylene glycol monoallyl ether and maleic anhydride, or a hydrolyzate or a salt thereof;
80, a copolymer of polyethylene glycol monoallyl ether, maleic acid, and a monomer copolymerizable with these monomers, or a salt or an ester thereof; and a polyalkylene glycol monoester as described in JP-B-59-18338. (Meth) acrylate monomers, (meth) acrylate monomers, and copolymers composed of monomers copolymerizable with these monomers.
Polycarboxylic acids (salts) such as (meth) acrylic acid esters having a sulfonic acid group and, if necessary, a monomer copolymerizable therewith, or salts thereof; it can.

The proportion of the polycarboxylic acid in the cement admixture is not particularly limited, but is preferably 10 to 100% by weight, more preferably 50 to 100% by weight, most preferably 80 to 100% by weight of the whole cement admixture. 100% by weight. When the proportion of the polycarboxylic acid is less than 10% by weight, the cement dispersing performance and the slump holding performance may be reduced.

The cement composition is a composition comprising cement, the cement admixture and water as essential components,
For example, it is used as cement paste, mortar, and concrete. As the cement, ordinary Portland cement is generally used, but in addition, for example, Portland cement such as early strength, ultra early strength, moderate heat, white, etc., alumina cement, fly ash cement, blast furnace cement, silica cement, etc. Mixed Portland cement can also be used.

The proportion of the cement admixture in the cement composition is not particularly limited, but is preferably 0.01 to 10% by weight (in terms of solid content), more preferably 0.05 to 5% by weight, based on the weight of the cement. % By weight. When the proportion of the cement admixture is less than 0.01% by weight, the performance is insufficient. On the contrary, when the proportion exceeds 10% by weight, it is disadvantageous in terms of economy.

The mutual ratio of cement and water in the cement composition is not particularly limited, but is preferably water / water.
Cement (weight ratio) = 0.1 to 0.7, more preferably 0.2 to 0.65. The unit water amount of the cement composition is not particularly limited, but is preferably 100 to 185 kg.
/ M ³ , more preferably 120 to 175 kg / m ³ .

The cement composition may contain components other than cement, cement admixture and water, and may be fine aggregate;
Coarse aggregate; fine powder such as fly ash, blast furnace slag, silica fume, limestone and the like can be contained.

[0040]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples, unless otherwise specified, "%"
And "parts" represent "% by weight" and "parts by weight", respectively. Hereinafter, first, after producing a polyalkylene glycol in Production Examples 1 to 5, an esterification reaction is performed to produce a polyalkylene glycol (meth) acrylate, and then a polyalkylene glycol (meth) acrylate and a (meth) acrylic acid-based A polycarboxylic acid was produced by copolymerizing with a monomer.

Production of polyalkylene glycol [1]
Production Example 1 For the preparation, 32 parts of methanol and 0.23 part of sodium hydroxide were charged into an autoclave equipped with a thermometer and a stirrer, and the inside of the vessel was sufficiently purged with nitrogen, and then heated to 70 ° C. After 132 parts of ethylene oxide was introduced into the autoclave over 1 hour, the ethylene oxide addition reaction was completed by maintaining the temperature at 70 ° C. for 1 hour to obtain an alcohol obtained by adding 3 mol of ethylene oxide to 1 mol of methanol. Subsequently, 155
After heating to ℃, 308 parts of ethylene oxide was introduced into an autoclave, and the addition reaction was completed at 155 ° C. for 1 hour to obtain methoxypolyethylene glycol (n = 10) as polyalkylene glycol [1].
The peroxide value of the obtained polyalkylene glycol [1] was measured by the method shown below, and was 0.2 meq / kg. [Method of measuring peroxide value] 10 g of polyalkylene glycol [1], 35 ml of chloroform and 35 m of acetic acid
l was placed in a flask, 1 ml of a saturated potassium iodide solution was added and the mixture was stirred while replacing the inside of the flask with nitrogen, and then left standing for 20 minutes to prepare a brown test solution. The test solution was titrated with 0.01 N sodium thiosulfate until the brown color of the solution disappeared, and the peroxide value was calculated according to the following formula.

Peroxide value (meq / kg) = (AB) × 10 / S (where A: titer of 0.01N-sodium thiosulfate required for titration of sample (ml), B: blank test 0 required.
Titration (ml) of 01N-sodium thiosulfate, S: Sampling amount (g) of sample. ) Production for producing polyalkylene glycol [2]
Example 2 The polyalkylene glycol [1] obtained in Production Example 1 was heated and melted in an air atmosphere to obtain a polyalkylene glycol [2]. The peroxide value of the polyalkylene glycol [2] was measured in the same manner as in Production Example 1;
0.8 meq / kg.

Production of polyalkylene glycol [3]
Production Example 3 For preparing an autoclave equipped with a thermometer and a stirrer, 32 parts of methanol and 0.55 part of sodium hydroxide were charged, and the inside of the vessel was sufficiently purged with nitrogen, and then heated to 70 ° C. After 132 parts of ethylene oxide was introduced into the autoclave over 1 hour, the ethylene oxide addition reaction was completed by maintaining the temperature at 70 ° C. for 1 hour to obtain an alcohol obtained by adding 3 mol of ethylene oxide to 1 mol of methanol. Subsequently, 155
After heating to ℃, 968 parts of ethylene oxide were introduced into the autoclave, and the addition reaction was completed at 155 ° C. for 1 hour to obtain methoxypolyethylene glycol (n = 25) as polyalkylene glycol [3].
The peroxide value of the obtained polyalkylene glycol [3] was measured by the same method as in Production Example 1, and was 0.2 meq / kg.
Met.

Production of polyalkylene glycol [4]
Production Example 4 To an autoclave equipped with a thermometer and a stirrer, 32 parts of methanol and 1.65 parts of sodium hydroxide were charged, the inside of the vessel was sufficiently purged with nitrogen, and then heated to 70 ° C. After 132 parts of ethylene oxide was introduced into the autoclave over 1 hour, the ethylene oxide addition reaction was completed by maintaining the temperature at 70 ° C. for 1 hour to obtain an alcohol obtained by adding 3 mol of ethylene oxide to 1 mol of methanol. Subsequently, 155
After the temperature was raised to 0 ° C and 3168 parts of ethylene oxide were introduced into the autoclave, the addition reaction was completed at 155 ° C for 1 hour to obtain methoxypolyethylene glycol (n = 75) as polyalkylene glycol [4]. The peroxide value of the obtained polyalkylene glycol [4] was measured in the same manner as in Production Example 1, and was determined to be 0.2 meq /
kg.

Production of polyalkylene glycol [5]
Production Example 5 For the preparation, 32 parts of methanol and 3.3 parts of sodium hydroxide were charged into an autoclave equipped with a thermometer and a stirrer, and the inside of the vessel was sufficiently purged with nitrogen, and then heated to 70 ° C. After 132 parts of ethylene oxide was introduced into the autoclave over 1 hour, the ethylene oxide addition reaction was completed by maintaining the temperature at 70 ° C. for 1 hour to obtain an alcohol obtained by adding 3 mol of ethylene oxide to 1 mol of methanol. Subsequently, 155 ° C
Then, 6468 parts of ethylene oxide were introduced into the autoclave, and the addition reaction was completed at 155 ° C. for 1 hour to obtain methoxypolyethylene glycol (n = 150) as polyalkylene glycol [5]. The peroxide value of the obtained polyalkylene glycol [5] was measured in the same manner as in Production Example 1, and was determined to be 0.2 meq /
kg.

Example 1 The peroxide value of 0.2 me obtained in Production Example 1 was placed in a glass reactor equipped with a thermometer, a stirrer, a produced water separator, and a reflux condenser.
q / kg of methoxy poly (n = 10) 1346 parts of ethylene glycol, 654 parts of methacrylic acid, 800 parts of benzene, 10 parts of sulfuric acid, and 0.5 part of hydroquinone are charged, and the temperature is increased with stirring to start the esterification reaction. . After confirming that a predetermined amount of produced water was distilled off, benzene was expelled and a predetermined amount of water was added to obtain an 80% aqueous solution of the monomer mixture [1]. The esterification rate was confirmed by liquid chromatography to be 99%, and polyethylene glycol dimethacrylate was not detected. The K value of the monomer mixture [1] was 65.

Next, water 1 was placed in a glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser.
900 parts were charged, the inside of the reactor was replaced with nitrogen under stirring, and the temperature was raised to 95 ° C. in a nitrogen atmosphere. An aqueous solution 200 obtained by adding 1000 parts of water to 1000 parts of the above monomer mixture [1].
0 parts for 4 hours and 10 parts ammonium persulfate in water 9
100 parts of an aqueous solution dissolved in 0 parts was dropped into the reactor in 5 hours. After completion of the dropwise addition, the temperature was maintained at 95 ° C. for another hour. Thereafter, the mixture was neutralized with an aqueous sodium hydroxide solution to obtain a polycarboxylic acid (1) having a molecular weight of 33,000.

Using the obtained polycarboxylic acid (1) as it is as a cement admixture (1), a cement composition (1) was prepared according to the following concrete test method.
Slump values were measured. Table 1 shows the results. [Concrete test method] The cement admixture (1) obtained above, ordinary Portland cement as a cement (mixing of three brands equivalent: specific gravity 3.16), and Oigawa water-based land sand and Kisarazu mountain sand as fine aggregate Mixed with sand (specific gravity 2.6
2, FM2.71), using a hard sandstone crushed stone from Ome (specific gravity 2.64, MS 20 mm) as coarse aggregate, kneading amount 5
0 L of the cement composition (1) was prepared. Table 1 shows the amount of the cement admixture (1) contained in the cement composition (1). The compounding conditions for preparing the cement composition (1) were a unit cement amount of 320 kg / m ³ , a unit water amount of 166 kg / m ³ (water / cement ratio: 51.9%), and a fine aggregate ratio of 47%. Regarding the cement composition (1), the slump (c) immediately after preparation, after 30 minutes and after 60 minutes
m) according to Japanese Industrial Standards (JIS A 1101, 112)
It measured by the method based on 8).

Example 2 In a glass reactor equipped with a thermometer, a stirrer, a produced water separator and a reflux condenser, the peroxide value obtained in Production Example 1 was 0.2 me.
q / kg of methoxy poly (n = 10) 1346 parts of ethylene glycol, 654 parts of methacrylic acid, 800 parts of benzene, 20 parts of methanesulfonic acid, 0.1 part of hydroquinone.
5 parts are charged, and the temperature is raised with stirring to start the esterification reaction. After confirming that a predetermined amount of produced water was distilled off, benzene was expelled and a predetermined amount of water was added to obtain an 80% aqueous solution of the monomer mixture [2]. The esterification rate was confirmed by liquid chromatography to be 99%, and polyethylene glycol dimethacrylate was not detected. The K value of the monomer mixture [2] was 65.

Next, water 1 was introduced into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser.
900 parts were charged, the inside of the reactor was replaced with nitrogen under stirring, and the temperature was raised to 95 ° C. in a nitrogen atmosphere. To 1000 parts of the above monomer mixture [2], add 30% aqueous sodium hydroxide solution 1
An aqueous solution obtained by adding 3 parts and 1000 parts of water was dropped into the reactor for 4 hours, and an aqueous solution obtained by dissolving 10 parts of ammonium persulfate in 90 parts of water was dropped for 5 hours. After completion of the dropwise addition, the temperature was maintained at 95 ° C. for another hour. Thereafter, the mixture was neutralized with an aqueous sodium hydroxide solution to pH 7.0, and had a molecular weight of 3,970.
0 polycarboxylic acid (2) was obtained.

Using the obtained polycarboxylic acid (2) as it is as a cement admixture (2), a cement composition (2) was prepared in the same manner as in Example 1, and the slump value was measured. Table 1 shows the results. Example 3 A peroxide value of 0.2 me obtained in Production Example 3 was placed in a glass reactor equipped with a thermometer, a stirrer, a produced water separator, and a reflux condenser.
1654 parts of q / kg of methoxypoly (n = 25) ethylene glycol, 372 parts of methacrylic acid, 800 parts of benzene, 10 parts of sulfuric acid, and 0.5 part of hydroquinone are charged, and the temperature is increased with stirring to start the esterification reaction. . After confirming that a predetermined amount of produced water was distilled off, benzene was expelled and a predetermined amount of water was added to obtain an 80% aqueous solution of the monomer mixture [3]. The esterification rate was confirmed by liquid chromatography to be 99%, and polyethylene glycol dimethacrylate was not detected. The K value of the monomer mixture [3] was 89.

Next, water 6 was introduced into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser.
69 parts were charged, the inside of the reactor was replaced with nitrogen under stirring, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. 1125 parts of the above monomer mixture [3] was added with 6.2-mercaptopropionic acid.
A solution in which 10 parts of ammonium persulfate was dissolved in 190 parts of water was dropped into the reactor over 4 hours, and an aqueous solution having 10 parts of ammonium persulfate dissolved in 190 parts of water was dropped over 5 hours. After the completion of dropping, it is 80 hours for another hour.
C was maintained. Then, pH is adjusted with sodium hydroxide aqueous solution.
Neutralized to 7.0 to obtain polycarboxylic acid (3) having a molecular weight of 23,000.

Using the obtained polycarboxylic acid (3) as it is as a cement admixture (3), a cement composition (3) was prepared in the same manner as in Example 1, and the slump value was measured. Table 1 shows the results. Example 4 A peroxide value of 0.2 me obtained in Production Example 4 was placed in a glass reactor equipped with a thermometer, a stirrer, a produced water separator, and a reflux condenser.
Charge 1/35 parts of q / kg of methoxypoly (n = 75) ethylene glycol, 374 parts of methacrylic acid, 800 parts of benzene, 10 parts of sulfuric acid and 0.5 part of hydroquinone, and raise the temperature under stirring to start the esterification reaction. . After confirming that a predetermined amount of produced water was distilled off, benzene was expelled and a predetermined amount of water was added to obtain an 80% aqueous solution of the monomer mixture [4]. The esterification rate was confirmed by liquid chromatography to be 99%, and polyethylene glycol dimethacrylate was not detected. The K value of the monomer mixture [4] was 50.

Next, water 1 was introduced into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser.
130 parts were charged, the inside of the reactor was replaced with nitrogen under stirring, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. A solution in which 167 parts of water and 3.7 parts of 3-mercaptopropionic acid were dissolved in 500 parts of the monomer mixture [4] was used for 4 hours, and an aqueous solution in which 4.6 parts of ammonium persulfate was dissolved in 190 parts of water was used. It was dropped into the reactor in 5 hours. After completion of the dropping, the temperature was maintained at 80 ° C. for another hour. Thereafter, the mixture was neutralized to pH 7.0 with an aqueous sodium hydroxide solution, and the molecular weight was 3,500.
0 polycarboxylic acid (4) was obtained. The obtained polycarboxylic acid (4) could be used as it is as a cement admixture (4).

Example 5 A peroxide value of 0.2 me obtained in Production Example 3 was placed in a glass reactor equipped with a thermometer, a stirrer, a produced water separator, and a reflux condenser.
Charge q / kg of methoxypoly (n = 25) 1491 parts of ethylene glycol, 533 parts of methacrylic acid, 800 parts of benzene, 10 parts of sulfuric acid, and 0.5 part of hydroquinone, and raise the temperature under stirring to start the esterification reaction. . After confirming that a predetermined amount of produced water was distilled off, benzene was driven out and a predetermined amount of water was added to obtain an 80% aqueous solution of the monomer mixture [5]. The esterification rate was confirmed by liquid chromatography to be 99%, and polyethylene glycol dimethacrylate was not detected. The K value of the monomer mixture [5] was 56.

Next, water 8 was introduced into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser.
Then, the reactor was purged with nitrogen while stirring, and the temperature was raised to 95 ° C. in a nitrogen atmosphere. A solution obtained by adding 167 parts of water to 800 parts of the above monomer mixture [5] was dropped into the reactor in 4 hours, and an aqueous solution in which 6.2 parts of ammonium persulfate was dissolved in 190 parts of water was dropped in 5 hours. After completion of the dropwise addition, the temperature was maintained at 95 ° C. for another hour. Thereafter, the mixture was neutralized to pH 7.0 with an aqueous sodium hydroxide solution, and the molecular weight was 22
000 polycarboxylic acids (5) were obtained.

Using the obtained polycarboxylic acid (5) as it was as a cement admixture (5), a cement composition (5) was prepared according to the following mortar test method, and the flow value was measured. Table 2 shows the results. [Mortar test method] Using a mortar mixer, 240 parts of the water containing the cement admixture (5) obtained above, 400 parts of ordinary Portland cement (made by Chichibu Onoda) as cement and 800 parts of Toyoura standard sand were mixed. And
A cement composition (5) was prepared. Table 2 shows the amount of the cement admixture (5) contained in the cement composition (5).

After the cement composition (5) was packed in a hollow cylinder having a diameter of 55 mm and a height of 50 mm, the cylinder was lifted vertically, and the diameter (two directions) of the expanded cement composition (5) was measured. The average value was taken as the flow value (mm). Flow values were measured immediately after preparation, after 30 minutes and after 60 minutes. -Example 6- A peroxide value of 0.2 me obtained in Production Example 3 was placed in a glass reactor equipped with a thermometer, a stirrer, a produced water separator, and a reflux condenser.
1573 parts of q / kg methoxypoly (n = 25) ethylene glycol, 452 parts of methacrylic acid, 800 parts of benzene, 10 parts of sulfuric acid, and 0.5 part of hydroquinone are charged, and the temperature is increased with stirring to start the esterification reaction. . After confirming that a predetermined amount of generated water was distilled off, benzene was driven out and a predetermined amount of water was added to obtain an 80% aqueous solution of the monomer mixture [6]. The esterification rate was confirmed by liquid chromatography to be 99%, and polyethylene glycol dimethacrylate was not detected. The K value of the monomer mixture [6] was 69.7.

Next, water 6 was introduced into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser.
67 parts were charged, the inside of the reactor was replaced with nitrogen under stirring, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. 7.5 g of 3-mercaptopropionic acid was added to 1125 parts of the above monomer mixture [6].
A solution in which 1 part was dissolved was dropped into the reactor for 4 hours, and an aqueous solution in which 10 parts of ammonium persulfate was dissolved in 190 parts of water was dropped into the reactor over 5 hours. After the end of the dropping, 8 hours
Maintained at 0 ° C. Then, p with aqueous sodium hydroxide solution
The mixture was neutralized to H7.0 to obtain a polycarboxylic acid (6) having a molecular weight of 23,000.

Using the obtained polycarboxylic acid (6) as it was as a cement admixture (6), a cement composition (6) was prepared in the same manner as in Example 5, and the flow value was measured. Table 2 shows the results. -Example 7-A peroxide value of 0.2 me obtained in Production Example 3 was placed in a glass reactor equipped with a thermometer, a stirrer, a produced water separator, and a reflux condenser.
1694 parts of q / kg of methoxypoly (n = 25) ethylene glycol, 333 parts of methacrylic acid, 800 parts of benzene, 10 parts of sulfuric acid, and 0.5 part of hydroquinone are charged, and the temperature is increased with stirring to start the esterification reaction. . After confirming that a predetermined amount of produced water was distilled off, benzene was expelled and a predetermined amount of water was added to obtain an 80% aqueous solution of the monomer mixture [7]. The esterification rate was confirmed by liquid chromatography to be 99%, and polyethylene glycol dimethacrylate was not detected. The K value of the monomer mixture [7] was 101.7.

Next, water 6 was introduced into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser.
70 parts were charged, the inside of the reactor was replaced with nitrogen under stirring, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. 5.5 g of 3-mercaptopropionic acid was added to 1125 parts of the above monomer mixture [7].
A solution in which 4 parts were dissolved was dropped into the reactor in 4 hours, and an aqueous solution in which 10 parts of ammonium persulfate was dissolved in 190 parts of water was dropped in 5 hours. After the end of the dropping, 8 hours
Maintained at 0 ° C. Then, p with aqueous sodium hydroxide solution
The solution was neutralized to H7.0 to obtain a polycarboxylic acid (7) having a molecular weight of 25,000.

Using the obtained polycarboxylic acid (7) as it is as a cement admixture (7), a cement composition (7) was prepared in the same manner as in Example 5, and the flow value was measured. Table 2 shows the results. Example 8 The peroxide value of 0.2 me obtained in Production Example 3 was placed in a glass reactor equipped with a thermometer, a stirrer, a produced water separator, and a reflux condenser.
Charge q / kg of methoxy poly (n = 25) 1741 parts of ethylene glycol, 287 parts of methacrylic acid, 800 parts of benzene, 10 parts of sulfuric acid, and 0.5 part of hydroquinone, and raise the temperature under stirring to start the esterification reaction. . After confirming that a predetermined amount of produced water was distilled off, benzene was driven out and a predetermined amount of water was added to obtain an 80% aqueous solution of the monomer mixture [8]. The esterification rate was confirmed by liquid chromatography to be 99%, and polyethylene glycol dimethacrylate was not detected. The K value of the monomer mixture [8] was 121.5.

Next, water 6 was introduced into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser.
69 parts were charged, the inside of the reactor was replaced with nitrogen under stirring, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. 6.6 parts of 3-mercaptopropionic acid was added to 1125 parts of the above monomer mixture [8].
A solution in which 3 parts were dissolved was dropped into the reactor over 4 hours, and an aqueous solution obtained by dissolving 10 parts of ammonium persulfate in 190 parts of water was dropped into the reactor over 5 hours. After the end of the dropping, 8 hours
Maintained at 0 ° C. Then, p with aqueous sodium hydroxide solution
It neutralized to H7.0, and obtained polycarboxylic acid (8) of molecular weight 35,000.

Using the obtained polycarboxylic acid (8) as it was as a cement admixture (8), a cement composition (8) was prepared in the same manner as in Example 5, and the flow value was measured. Table 2 shows the results. -Example 9-The peroxide value of 0.2 me obtained in Production Example 5 was placed in a glass reactor equipped with a thermometer, a stirrer, a produced water separator, and a reflux condenser.
1819 parts of q / kg methoxypoly (n = 150) ethylene glycol, 186 parts of methacrylic acid, 800 parts of benzene, 10 parts of sulfuric acid, and 0.5 part of hydroquinone were charged, and the temperature was increased with stirring to start the esterification reaction. . After confirming that a predetermined amount of produced water was distilled off, benzene was expelled and a predetermined amount of water was added to obtain an 80% aqueous solution of the monomer mixture [9]. The esterification rate was confirmed by liquid chromatography to be 99%, and polyethylene glycol dimethacrylate was not detected. The K value of the monomer mixture [9] was 79.8.

Next, water 6 was introduced into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser.
69 parts were charged, the inside of the reactor was replaced with nitrogen under stirring, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. A solution in which 300 parts of water and 4.59 parts of 3-mercaptopropionic acid were dissolved in 500 parts of the above monomer mixture [9] for 4 hours, and an aqueous solution in which 4.6 parts of ammonium persulfate was dissolved in 190 parts of water was used. It was dropped into the reactor in 5 hours. After completion of the dropping, the temperature was maintained at 80 ° C. for another hour. Thereafter, the mixture was neutralized with an aqueous sodium hydroxide solution to pH 7.0, and had a molecular weight of 4500.
0 polycarboxylic acid (9) was obtained.

Using the obtained polycarboxylic acid (9) as it was as a cement admixture (9), a cement composition (9) was prepared in the same manner as in Example 5, and the flow value was measured. Table 2 shows the results. -Example 10-The peroxide value of 0.2 me obtained in Production Example 1 was placed in a glass reactor equipped with a thermometer, a stirrer, a produced water separator, and a reflux condenser.
Charge q / kg of methoxy poly (n = 10) 1346 parts of ethylene glycol, 654 parts of methacrylic acid, 660 parts of benzene, 80 parts of sulfuric acid, and 0.5 part of hydroquinone, and raise the temperature under stirring to start the esterification reaction. . After confirming that a predetermined amount of produced water was distilled off, benzene was expelled and a predetermined amount of water was added to obtain an 80% aqueous solution of the monomer mixture [10]. The esterification rate was confirmed by a liquid chromatogram to be 99% and contained 12% of polyethylene glycol dimethacrylate. Monomer mixture [1
0] was 65.

Next, water 1 was introduced into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser.
900 parts were charged, the inside of the reactor was replaced with nitrogen under stirring, and the temperature was raised to 95 ° C. in a nitrogen atmosphere. Monomer mixture [1
0] A solution obtained by adding 1000 parts of water to 1000 parts was added for 4 hours.
In addition, an aqueous solution in which 13.5 parts of ammonium persulfate was dissolved in 86.5 parts of water was dropped into the reactor over 5 hours. After completion of the dropwise addition, the temperature was maintained at 95 ° C. for another hour. afterwards,
The solution was neutralized to pH 7.0 with an aqueous sodium hydroxide solution to obtain a polycarboxylic acid (10) having a molecular weight of 35,700.

Using the obtained polycarboxylic acid (10) as it is as a cement admixture (10), a cement composition (10a) was prepared in the same manner as in Example 1, and the slump value was measured. Table 1 shows the results. Using the cement admixture (10), a cement composition (10b) was prepared in the same manner as in Example 5, and the flow value was measured. Table 2 shows the results.

Comparative Example 1 A peroxide value of 0.8 me obtained in Production Example 2 was placed in a glass reactor equipped with a thermometer, a stirrer, a produced water separator, and a reflux condenser.
q / kg of methoxypolyethylene glycol (n = 1
0) 1346 parts, 654 parts of methacrylic acid, 660 parts of benzene, 20 parts of sulfuric acid, and 0.5 part of hydroquinone were charged, and the temperature was raised with stirring to start the esterification reaction. After a while, the esterification reaction was interrupted because a large amount of gel adhered to the stirring blade, the stirring rod, and the thermometer, but polyalkylene glycol methacrylate could be isolated from the reaction mixture. Polyalkylene glycol dimethacrylate was not detected. When the reaction mixture at the time of the esterification reaction was used as a monomer mixture, its K value was 65.

To the obtained polyalkylene glycol methacrylate, methacrylic acid was added and copolymerized in the same manner as in Example 1 to obtain a comparative polycarboxylic acid (1) having a molecular weight of 33,000.
I got Comparative polycarboxylic acid (1) had the same physical properties as polycarboxylic acid (1) having the same molecular weight. -Reference Example 1-Naphthalenesulfonic acid formaldehyde condensate salt (NS
Using F) as a reference cement admixture (1), a reference cement composition (1) was prepared in the same manner as in Example 1, and the slump value was measured. Table 1 shows the results.

[0071]

[Table 1]

[0072]

[Table 2]

Table 1 shows that the cement admixtures (1) to (3) and (10), which are the cement admixtures of the present invention, used a smaller amount than the reference cement admixture (1) and produced a slump (immediately after preparation). It can be seen that 18 cm can be achieved, the dispersing performance is high, and the change with time of the slump value is small. Although the performance of the cement admixture (10) is slightly lower than that of the cement admixtures (1) to (3), the same performance can be obtained by increasing the blending amount.

Table 2 shows that the cement admixtures (5) to (1)
0) shows that the dispersion performance is high, the change in the flow value with time is small, and the slump holding performance is high.

[0075]

According to the method for producing an ester for producing a cement admixture according to the present invention, a polyalkylene glycol (meth) acrylate can be obtained with high productivity without generating a gel.

Claims (3)

[Claims] 1. A method for obtaining a polyalkylene glycol (meth) acrylate by subjecting a polyalkylene glycol and a (meth) acrylic acid-based monomer to esterification as raw materials, wherein the polyalkylene glycol has a peroxide value of 0. A method for producing an ester for producing a cement admixture, comprising using a polyalkylene glycol having a concentration of 0.7 meq / kg or less. 2. The polyalkylene glycol of the following general formula (1): ## STR1 ## (Wherein R ¹ O is one or two of an oxyalkylene group)
A mixture of two or more species, and in the case of two or more species, they may be added in a block shape or in a random shape;
² represents an alkyl group having 1 to 22 carbon atoms, a phenyl group, or an alkylphenyl group, and n represents an average number of added moles of the oxyalkylene group, and represents a number of 1 to 300. Wherein the (meth) acrylic acid-based monomer is represented by the following general formula (2): The method for producing an ester for producing a cement admixture according to claim 1, wherein the ester is a (meth) acrylic acid-based monomer (B) represented by the formula (wherein, R ³ represents hydrogen or a methyl group). 3. The polyalkylene glycol (A)
Parts by weight and b of the (meth) acrylic acid monomer (B)
Each part by weight is charged into a reactor within the range of the following formula (1) {(a / n ^1/2 ) / b} × 100 ≦ 200 (1) to perform an esterification reaction.
A method for producing an ester for producing a cement admixture according to claim 1 or 2.