JP2013082559A - Admixture for hydraulic composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cement dispersant that is excellent in water-reducing property, causes no delay in coagulation, yields fresh concrete that can be easily kneaded and mixed due to low viscosity and is excellent in workability.SOLUTION: An admixture for a hydraulic composition comprises copolymers obtained by reacting monomer (a), monomer (b) and, if necessary, monomer (c), or salts thereof (A) and (B), provided that (A) is a copolymer or a salt thereof wherein the copolymerization ratio by mass of monomers (a)-(c) is (a):(b):(c)=(50-95):(5-50):(0-40) and (B) is a copolymer or a salt thereof wherein (a):(b):(c)=(0-45):(5-30):(30-90). Here, monomer (a) is an ester compound obtained by adding 0-10 mole 2-4C alkylene oxide to 1 mole compound represented by formula (1): RO-(AO)n-H and further reacting the resulting adduct with α, β-unsaturated carboxylic acid, copolymer (b) is α,β-unsaturated carboxylic acid or a salt thereof, and monomer (c) is another copolymerizable monomer.

Description

  The present invention relates to water comprising two kinds of copolymers having different copolymerization ratios or salts thereof using polyalkylene glycol alkyl ether and unsaturated carboxylic acid ester compound in which the content ratio of alkylene oxide is small but the content ratio is reduced. The present invention relates to an admixture for a hard composition. In particular, the present invention relates to an admixture for a hydraulic composition made of the above-mentioned copolymer, excellent in water reduction, free from setting delay, low in viscosity of fresh concrete, easy to knead, and excellent in workability.

Cement dispersants, which reduce the unit water content in concrete for the purpose of improving the durability and ensuring strength of concrete, are now essential chemical admixtures in concrete production. Among the cement dispersants, the high-performance AE water reducing agent mainly composed of a polycarboxylic acid polymer is excellent in the effect of reducing the unit amount of water, and also has the transportation time from the production site of ready-mixed concrete to the setting site. In the meantime, a desired consistency can be achieved and good workability can be ensured (high slump retention or reduction of slump loss), which is further excellent in reducing work defects. As a result, it is possible to produce concrete products with reduced unit water in factories that produce secondary concrete products, and the number of high-strength precast members has increased.
At the same time as technological development for high-performance AE water reducing agents is being promoted, construction techniques and construction methods using newly developed cement dispersants have been established, and new problems and requirements have arisen accordingly. For example, since the advent of a cement dispersant using a basic polycarboxylic acid polymer as disclosed in Patent Document 1, in order to respond to newly born problems and demands, a polycarboxylic acid type used in a cement dispersant Various proposals have been made on the molecular weight and structure of polymers.
For example, it is intended to improve slump retention by controlling the molecular weight of a polycarboxylic acid polymer to an appropriate range (Patent Document 2). For the purpose of improving the efficiency and labor saving of the work site, various monomer compositions are used. Time-dependent decrease in fluidity (slump loss) by providing a polycarboxylic acid polymer comprising a combination of restrictions and graft side chains different (5 to 25, 40 to 109 in terms of added moles of ethylene oxide) Derived from a carboxylic acid monomer having an alkoxy group or a hydroxyalkoxy group for the purpose of suppressing flow rate, early demolding of a formwork and early strength development (Patent Document 3), aiming to realize fluidity and strength development Various proposals have been made, such as those providing a polycarboxylic acid polymer having a polymer structure (Patent Document 4). In addition, by setting the molecular weight of the polycarboxylic acid polymer to 5,000 or more and less than 10,000 and setting the value of weight average molecular weight / number average molecular weight to 1.0 or more and 1.5 or less, high pore permeability, fluidity There has also been a proposal that a cement dispersant having the properties and strength development can be provided (Patent Document 5).
In this way, controlling the molecular weight and structure of the polycarboxylic acid polymer in the cement dispersant causes a great change in the working environment at the concrete manufacturing and construction site. Further improvements in polymerization accuracy have been desired in order to fully meet higher needs.

  On the other hand, various problems associated with the introduction of the polycarboxylic acid-based polymer and problems to be solved that have been expected have started to appear. For example, there is a problem of reducing the performance change of the cement water reducing agent with temperature. This is because the performance of water reduction etc. is slow in winter, so even if the fluidity is adjusted moderately in the ready-mixed concrete factory, the fluidity is required due to the delay in performance when it reaches the construction site. As a result of the above-described improvement, non-uniform placement accompanied with separation during construction results in problems such as variations in strength. On the other hand, in summer, it is difficult to ensure the consistency for the required time due to the effect of hydration of the cement being accelerated by the temperature rise, so it is desired that the desired consistency can be maintained for a long time. .

Japanese Patent Publication No.59-18338 JP-A-9-86990 JP 11-246250 A JP 2003-286057 A JP 2005-281022 A

  The present invention provides an admixture for a hydraulic composition that is excellent in dispersibility, in particular, excellent in water reduction of cement, has no setting delay, has low viscosity of fresh concrete and is easy to knead, and has excellent workability. Is an issue.

  As a result of intensive studies, the inventors of the present invention have used, as a monomer component, an ester compound that is a (meth) acrylate of a polyalkylene glycol alkyl ether and has a reduced content ratio of a small number of added moles of alkylene oxide. When two types of copolymers having different copolymerization ratios were used in combination, it was found that the above problems could be solved and the present invention was achieved.

That is, the present invention is a copolymer obtained by reacting the following monomers (a), (b) and, if necessary, (c) or a salt thereof, wherein the monomers (a) to (c) A copolymer or a salt thereof (A) having a copolymerization ratio of (a) :( b) :( c) = 50 to 95%: 5 to 50%: 0 to 40%, and (a): (B): It is related with the admixture for hydraulic compositions containing the copolymer which is 0-45%: 5-30%: 30-30%, or its salt (B).
(A) The following general formula (1):
R ¹ O— (AO) n—H (1)
(In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, A represents an alkylene group having 2 to 4 carbon atoms, n represents the number of added moles of alkylene oxide and represents an integer of 0 to 7) Represents.)
Ester obtained by adding 0 to 10 moles of alkylene oxide having 2 to 4 carbon atoms to 1 mole of at least one compound represented by formula (1) and further reacting the adduct with an α, β-unsaturated carboxylic acid However, as a compound represented by the formula (1), the content ratio of the compound having n of 3 or less based on the total mass of the compound represented by the formula (1) is 5% by mass or less. An ester compound obtained using a certain one,
(B) an α, β-unsaturated carboxylic acid or salt thereof, and (c) other copolymerizable monomers as required.

（式中、Ｒ^２は炭素原子数１〜１２のアルキル基を表し、Ｒ^３は水素原子又はメチル基を表し、Ａは炭素原子数２〜４のアルキレン基を表し、ｍはアルキレンオキサイドの付加モル数であって０〜１５の整数を表す。）
で表される少なくとも一種のエステル化合物であって、該化合物のうちｍが３以下の化合物の含有割合が、該化合物全体の質量に基づいて５質量％以下であり、かつ、ｍの平均値が４．０〜８．５である化合物、
（ｂ）α，β−不飽和カルボン酸又はその塩、及び
（ｃ）必要に応じその他の共重合可能な単量体
を反応して得られる共重合体もしくはその塩。 The present invention also provides a copolymer obtained by reacting the following monomers (a), (b) and, if necessary, (c), or a salt thereof, comprising monomers (a) to (c) A copolymer or a salt thereof (A) having a copolymerization ratio of (a) :( b) :( c) = 50 to 95%: 5 to 50%: 0 to 40%, and (a): (B): It is related with the admixture for hydraulic compositions containing the copolymer which is 0-45%: 5-30%: 30-30%, or its salt (B).
(A) The following general formula (2):

(In the formula, R ² represents an alkyl group having 1 to 12 carbon atoms, R ³ represents a hydrogen atom or a methyl group, A represents an alkylene group having 2 to 4 carbon atoms, and m represents addition of an alkylene oxide. The number of moles represents an integer of 0 to 15.)
The content ratio of the compound having m of 3 or less in the compound is 5% by mass or less based on the total mass of the compound, and the average value of m is A compound that is 4.0-8.5,
(B) Copolymer or salt thereof obtained by reacting α, β-unsaturated carboxylic acid or a salt thereof, and (c) other copolymerizable monomer as required.

  According to the present invention, it is possible to provide an admixture for a hydraulic composition that is excellent in water reduction, has a low setting delay, and has good workability such as low concrete viscosity not only immediately after discharge but also after a certain period of time.

FIG. 1 is a graph showing the distribution of the number of moles of ethylene oxide added between polyethylene glycol monomethyl ether a2 obtained in Synthesis Example 2 and polyethylene glycol monomethyl ether x2 obtained in Comparative Synthesis Example.

The present invention is greatly characterized in that an α, β-unsaturated carboxylic acid ester compound of a polyalkylene glycol alkyl ether in which the proportion of the added mole number of alkylene oxide is reduced to 3 mol or less is used as one component of the copolymer. Have
The present inventors have studied variously the structure of a copolymer useful as a cement dispersant, the types and proportions of monomers constituting the copolymer, and the molecular weight thereof. As a result, in the ester compound of polyalkylene glycol alkyl ether useful as one component of the copolymer, it has been found that the control of the distribution of the number of moles of alkylene oxide greatly affects the performance improvement of the cement dispersant. It was.

On the other hand, Hitada et al. [General paper] “High-performance AE water reducing agent for concrete based on polymethacrylic acid-polyethylene glycol graft copolymer”, Polymer Papers, Vol. 65, no. 11, pp. In 659-669 (Nov., 2008), in order to obtain a low-viscosity concrete with good properties, a long-chain polyalkylene glycol having an average added mole number of ethylene oxide of about 30 with respect to the side chain of the polycarboxylic acid. On the other hand, when an extremely short-chain polyalkylene glycol having an average added mole number of less than 10 is used for the side chain, the hydrophobicity is increased, and the air amount and the fluidity at high temperature are deteriorated. It was common knowledge for those skilled in the art that there was a problem. For this reason, conventionally, it has been common to use a polyalkylene glycol alkyl ether having an average added mole number of at least 9 or more as one component of a polycarboxylic acid polymer.
This was the conventional common knowledge, and the present inventors have surprisingly controlled polyalkylene glycol alkyl ether having a very low average added mole number by controlling the addition mole distribution of ethylene oxide. It was found for the first time that it was possible to create a cement dispersant capable of solving the above-mentioned problems and exhibiting excellent performance even when it was the main constituent of the polymer, and the present invention was completed here. is there.

More specifically, a polyalkylene glycol alkyl ether, which is one component of a polycarboxylic acid polymer, is usually prepared by adding a desired amount of alkylene oxide to an alcohol. According to the conventional production method, in the polyalkylene glycol alkyl ether, the distribution of the number of added moles of alkylene oxide becomes wide, and the distribution becomes wider as the number of added moles of alkylene oxide increases.
Therefore, the present inventors use a polyalkylene glycol whose addition mole distribution is controlled by a technique such as distillation or catalyst selection in order to select only a polyalkylene glycol having an ethylene oxide addition mole number suitable for a cement dispersant. The polycarboxylic acid polymer to be used was examined. In examining various polyalkylene glycols with controlled addition mole number distribution, by controlling the content of alkylene oxide having an addition mole number of 3 or less to 5% by weight or less, temperature dependence, air volume The inventors have found the fact that a polycarboxylic acid polymer satisfying all fluctuations and concrete viscosity can be obtained. Further, such a polycarboxylic acid polymer was also accompanied by the result that the mixing and setting of the concrete was accelerated.
Although the relationship between the performance of the polycarboxylic acid polymer of the present invention and the controlled polyalkylene glycol has not been clearly clarified, 3 moles of the added mole number of the alkylene oxide of the polyalkylene glycol alkyl ether was reduced. There is a change in hydrophilicity and hydrophobicity at the boundary, and by controlling the amount to a certain amount, it is considered that a cement dispersant having stable properties far exceeding the conventional expectation was obtained.
The present invention will be described in detail below.

<(A) Ester compound>
The ester compound of (a) polyalkylene glycol alkyl ether and α, β-unsaturated carboxylic acid in the present invention is represented by the following general formula (1):
R ¹ O— (AO) n—H (1)
(In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, A represents an alkylene group having 2 to 4 carbon atoms, n represents the number of added moles of alkylene oxide and represents an integer of 0 to 7) Represents.)
Ester obtained by adding 0 to 10 moles of alkylene oxide having 2 to 4 carbon atoms to 1 mole of at least one compound represented by formula (1) and further reacting the adduct with an α, β-unsaturated carboxylic acid A compound.
In the present invention, the compound represented by the formula (1) is a compound having a small content of n of 3 or less, that is, an alkylene oxide based on the total mass of the compound represented by the formula (1). In which the content ratio of the compound having an added mole number n of 3 or less is 5% by mass or less.

In the general formula (1), R ¹ is preferably an alkyl group having 1 to 8 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, and a tert-butyl group.
Specific examples of AO include an ethyleneoxy group, a propyleneoxy group, and a butyleneoxy group.

The compound represented by the formula (1) used in the present invention: a polyalkylene glycol alkyl ether having an alkylene oxide addition mole number n of 3 or less, a content ratio of 5% by mass or less, that is, addition of alkylene oxide. It is a compound in which the number of moles is more distributed in the range of about 4 to 6 (the distribution of added mole numbers is narrow).
In the present invention, by further reducing the polyalkylene glycol chain having a short chain length, it is possible to further reduce the influence on the air amount in the concrete and the influence due to the temperature change during construction. It is preferable to use an oxide having an added mole number of 3 or less and a content ratio of 3% by mass or less, and more preferably 1% by mass or less.
In the compound represented by the above formula (1), the average number of added moles of alkylene oxide is preferably 4 to 6, more preferably 4 to 5.
Thus, the ether compound which reduced the polyalkylene glycol chain | strand with a short chain length, for example with respect to 1 mol of C1-C12 monohydric alcohols, C2-C4 alkylene oxide in presence of an alkali catalyst. Can be obtained by adding about 4 moles, and then separating those having a number of moles of 3 or less by a fractionation operation such as distillation.
Moreover, what was obtained directly without passing through fractionation operation, such as distillation, by adding an alkylene oxide to presence of an acid catalyst etc. with respect to C1-C12 monohydric alcohol.

If necessary, the polyalkylene glycol alkyl ether may further contain 0 to 10 moles of alkylene oxide having 2 to 4 carbon atoms.
As shown in Examples (Synthesis Examples) described later and FIG. 1, a polyalkylene glycol alkyl ether having a reduced content ratio of those having an addition mole number of 3 or less is obtained, and an alkylene oxide is further added thereto. The resulting compound (Synthesis Example 2: Compound a2) has a narrower distribution of the number of moles of alkylene oxide added than that obtained by adding an alkylene oxide to alcohol in one step using an alkali catalyst (Comparative Synthesis Example: Compound x2). The result is.

The polyalkylene glycol alkyl ether obtained by the above-described method or the like may be directly reacted with an α, β-unsaturated carboxylic acid to obtain (A) an ester compound, or a plurality of different polyalkylene glycol chain length ranges. Various polyalkylene glycol alkyl ethers may be used in combination.
Examples of the α, β-unsaturated carboxylic acid include those similar to those used as the later-described (b), but acrylic acid and methacrylic acid are preferable from the viewpoint of effect and economy.

で表される少なくとも一種のエステル化合物であって、ここで式（２）で表される化合物のうち、ｍが３以下の化合物の含有割合が、該化合物全体の質量に基づいて５質量％以下であり、かつ、ｍの平均値が４．０〜８．５である化合物であってもよい。
なお、上記式中、Ｒ^２は炭素原子数１〜１２のアルキル基を表し、Ｒ^３は水素原子又はメチル基を表し、Ａは炭素原子数２〜４のアルキレン基を表し、ｍはアルキレンオキサイドの付加モル数であって０〜１５の整数を表す。Ｒ^１及びＡの好ましい基は前述のＲ及びＡで定義したものと同義である。 The ester compound (a) of the present invention has the following general formula (2):

In the compound represented by the formula (2), the content ratio of the compound having m of 3 or less is 5% by mass or less based on the total mass of the compound. And a compound having an average value of m of 4.0 to 8.5.
In the above formula, R ² represents an alkyl group having 1 to 12 carbon atoms, R ³ represents a hydrogen atom or a methyl group, A represents an alkylene group having 2 to 4 carbon atoms, and m represents an alkylene oxide. And represents an integer of 0 to 15. Preferred groups for R ¹ and A have the same definitions as defined for R and A above.

<(B) α, β-unsaturated carboxylic acid or salt thereof>
(B) As the α, β-unsaturated carboxylic acid (salt), for example, (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, maleic Acid half esters, fumaric acid half esters; and alkali metal (lithium, sodium, potassium, etc.) salts, alkaline earth metal (calcium, magnesium, etc.) salts, ammonium (ammonium, tetraoctyl ammonium, etc.) salts, organic amines { Alkanolamines, polyalkylenepolyamines or derivatives thereof (alkylated products, alkylene oxide adducts), lower alkylamines and the like} salts, and combinations of two or more of these. Of these, preferred are (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, alkali metal salts, alkaline earth metal salts or ammonium salts thereof, and combinations of two or more thereof.

<Other monomer (c)>
In the present invention, in addition to the above-mentioned monomers (a) and (b), other copolymerizable monomers (c) can be copolymerized as necessary. Other copolymerizable monomers include polyalkylene glycol monoalkenyl ether, polyalkylene glycol mono (meth) acrylate, (meth) allyl sulfonic acid (salt), styrene sulfonic acid (salt), (meth) acrylic acid It is a compound exemplified as a monomer for conventional polycarboxylic acid-based cement dispersants such as alkyl ester, styrene, (meth) acrylamide, etc., and a single amount copolymerizable with the monomers (a) and (b) If it is a body, the kind will not be specifically limited.
The monomer (c) has the same structure as the monomer (a) ester compound, provided that the alkyl chain length and alkylene oxide addition mole number defined in the present invention (for example, the addition mole number is from 20 moles to 20 moles). Ester compounds of polyalkylene glycol alkyl ethers with different (such as 50 moles) may be used.

  Among these, examples of the polyalkylene glycol monoalkenyl ether include alkenyl ethers formed from polyalkylene glycol and alkenyl ether having 3 to 8 carbon atoms. Specifically, 3-methyl-3-butene-1 -All alkylene oxide adducts, 2-methyl-2-propen-1-ol (methallyl alcohol) alkylene oxide adducts, 2-propen-1-ol (allyl alcohol) alkylene oxide adducts and ethers thereof Etc. Specific examples of the polyalkylene glycol mono (meth) acrylate include polyethylene glycol monomethacrylate, polyethylene glycol monoacrylate, polypropylene glycol monomethacrylate, polypropylene glycol monoacrylate, polyethylene polypropylene glycol monomethacrylate, polyethylene polypropylene glycol monoacrylate, and the like. Can be mentioned.

  The copolymer of the present invention comprises, as monomers, a polyalkylene polyamine (compound d) and a dibasic acid or an ester of a dibasic acid and a lower alcohol having 1 to 4 carbon atoms (compound e) with acrylic acid or methacrylic acid. A specific amount of alkylene oxide (compound g) was added to a polyamide polyamine obtained by condensing acid or acrylic acid or methacrylic acid with an ester of a lower alcohol having 1 to 4 carbon atoms (compound f) at a specific ratio. A compound can also be copolymerized.

  Examples of the polyalkylene polyamine of the compound d include, but are not limited to, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, dipropylenetriamine, tripropylenetetramine, and tetrapropylenepentamine. is not.

  As the dibasic acid of compound e and its lower alcohol ester having 1 to 4 carbon atoms, for example, malonic acid, succinic acid, fumaric acid, maleic acid, glutaric acid, adipic acid, pimelic acid, phthalic acid, azelaic acid, sebacic acid Or esters of these lower alcohols having 1 to 4 carbon atoms, such as methanol, ethanol, propanol, butanol or their isomers if present. Of these, adipic acid is most preferred from the viewpoints of effects and economy.

  As the acrylic acid or methacrylic acid of the compound f and its lower alcohol ester having 1 to 4 carbon atoms, for example, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, methacryl Examples include propyl acid, butyl acrylate, and butyl methacrylate.

  Polyamide polyamine composed of the above three components d, e and f can be easily obtained by a known condensation polymerization technique. Moreover, the C2-C4 alkylene oxide which is the compound g added to the amino residue of polyamide polyamine is ethylene oxide, propylene oxide, or butylene oxide. These alkylene oxides may be used alone or in combination of two or more.

  In the production of polyamide polyamine, that is, in the polycondensation reaction of compounds d, e and f, for example, only compound d and compound e are first subjected to polycondensation, and then monobasic acid compound f is added to further polycondensation. Or a batch reaction method in which the compounds d, e, and f are mixed simultaneously from the beginning to perform condensation polymerization. However, regardless of which method is used, the polycondensation reaction, that is, the amide reaction, proceeds in parallel with the amide exchange reaction, so that the acrylic acid residue or methacrylic acid residue derived from the compound f is finally converted to the polyamide. It will be located at the end of the chain and may be considered to give the same result.

  Next, the reaction molar ratio of the three components constituting the polyamide polyamine will be described. The reaction ratio of compound e (dibasic acid or ester thereof) to 1.0 mol of compound d (polyalkylene polyamine) is 0.5 to 0.95 mol. The polycondensation product of compound d and compound e reacted in a molar ratio within this range is on average (polyalkylene polyamine 2 mol: dibasic acid 1 mol) to (polyalkylene polyamine 20 mol: dibasic acid 19 mol). Thus, a polyamide having a certain range of chain length constituted by polycondensation of the polymer is obtained. From this, the dispersant obtained by using this exhibits high water-reducing property and sustainability of slump flow. When the chain length of this polyamide is shorter than this (when the said reaction ratio is less than 0.5 mol), a certain polyamide polyamine structure cannot be obtained. On the other hand, when the chain length is longer than this (when the reaction ratio exceeds 0.95 mol), the water-reducing property is considerably lowered, which is not preferable.

  The amount of alkylene oxide to be added to the polyamide polyamine is 0 to 8 mol with respect to 1 equivalent of the amino residue of the polyamide polyamine. If it exceeds 8 moles, the molecular weight of Compound A increases, so that the cation equivalent is lowered, and a sufficient effect as the amphoteric polymer of the present invention cannot be obtained. In the present invention, the above alkylene oxide is preferably added, and the amount thereof is preferably 0.5 to 6.0 mol, particularly preferably 1.0 to 5 with respect to 1 equivalent of the amino residue of the polyamide polyamine. .5 moles.

<Copolymerization ratio>
The copolymer or its salt (A) has a copolymerization ratio of (a) :( b) :( c) = 50 to 95%: 5 to 50%: 0 to 40%. It is preferable that (a) :( b) :( c) = 70 to 90%: 10 to 30%: 0 to 20% in terms of enhancing retention and reducing concrete viscosity.
The copolymer or its salt (B) has a copolymerization ratio of (a) :( b) :( c) = 0-45%: 5-30%: 30-90%. (A) :( b) :( c) = 3 to 40%: 7 to 25%: 35 to 90% is preferable in terms of enhancing the properties and reducing the concrete viscosity.

  The weight ratio of (A) to (B) is preferably (A) / (B) = 1/99 to 99/1, more preferably 10/90 to 90/10, and even more preferably 30/70. ~ 70/30.

  It does not specifically limit as a manufacturing method for obtaining the copolymer of this invention, For example, well-known polymerization methods, such as solution polymerization using a polymerization initiator and block polymerization, are applicable.

  The solution polymerization method can be carried out batchwise or continuously. Solvents used here include water, alcohols: methanol, ethanol, isopropanol, and other aromatic or aliphatic hydrocarbons; benzene, toluene, xylene. , Cyclohexane, n-hexane, etc., ester or ketone compounds; ethyl acetate, acetone, methyl ethyl ketone, etc., cyclic ether compounds; tetrahydrofuran, dioxane, etc., but water from the solubility of the raw material monomers and the resulting copolymer It is preferable to use at least one selected from the group consisting of lower alcohols having 1 to 4 carbon atoms, and it is more preferable to use water as a solvent among them.

  When carrying out aqueous solution polymerization, water-soluble polymerization initiators such as persulfates; ammonium persulfate, sodium persulfate, potassium persulfate, hydrogen peroxide, azoamidine compounds; 2,2 ′ -Cyclic azoamidine compounds such as azobis-2-methylpropionamidine hydrochloride; water-soluble azo compounds such as 2,2'-azobis-2- (2-imidazolin-2-yl) propane hydrochloride; 2-carbamoylazo An azonitrile compound such as isobutyronitrile is used. In this case, an alkali metal sulfite such as sodium bisulfite, a metabisulfite, a sodium hypophosphite, a Fe (II) salt such as a Mole salt, and hydroxymethane sulfone. Acid sodium dihydrate, hydroxylamine salts, thiourea, L-ascorbic acid (salt), It can also be used in combination accelerator such Risorubin acid (salt).

  For solution polymerization using a lower alcohol, aromatic or aliphatic hydrocarbon, ester compound, or ketone compound as a solvent, peroxides; hydroperoxides such as benzoyl peroxide, lauroyl peroxide, sodium peroxide; -Azo compounds such as butyl hydroperoxide and cumene hydroperoxide; azobisisobutyronitrile, etc. are used at the start of radical polymerization. In this case, an accelerator such as an amine compound can be used in combination. Furthermore, when a water-lower alcohol mixed solvent is used, it can be appropriately selected from the above-mentioned various radical polymerization initiators or combinations of radical polymerization initiators and accelerators.

  When performing bulk polymerization, peroxides as radical polymerization initiators; hydroperoxides such as benzoyl peroxide, lauroyl peroxide and sodium peroxide; azo compounds such as t-butyl hydroperoxide and cumene hydroperoxide; Azobisisobutyronitrile is used.

  The reaction temperature at the time of copolymerization is not particularly limited. For example, when persulfate is used as an initiator, the reaction temperature is suitably in the range of 30 to 95 ° C.

  A chain transfer agent can be used in the copolymerization. Examples of chain transfer agents include mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycolate, octyl 3-mercaptopropionate, 2-mercaptoethanesulfonic acid, etc. Thiol chain transfer agents can be used, and two or more types of chain transfer agents can be used in combination.

  The polymerization time at the time of copolymerization is not particularly limited, but for example, a range of 0.5 to 10 hours is appropriate, preferably 0.5 to 8 hours, more preferably 0.5 to 6 hours. good. If the polymerization time is too short or too long than this range, the polymerization rate is lowered and the productivity is lowered, which is not preferable.

  The dropping method during copolymerization is not particularly limited, but a method in which a part or all of each monomer is charged into a reaction vessel and an initiator or the like is dropped, one or more of each monomer is charged in a reaction vessel, Method of dropping a monomer, an initiator, a chain transfer agent, etc., a mixture of monomers, a radical polymerization initiator, a method of dropping a chain transfer agent, a mixture of each monomer and a chain transfer agent, initiation of radical polymerization The method of dripping each agent may be mentioned. It is also a commonly performed technique to shift the charging timing of each monomer in accordance with the reactivity of each monomer.

  The copolymer obtained by the above production method can be applied as a cement dispersant even in an acidic state, but from the viewpoint of suppressing ester hydrolysis due to acidity, it is made into a salt form by neutralization with alkali. Is preferred. Examples of the alkali include alkali metal or alkaline earth metal hydroxide, ammonia, mono, di, and trialkyl (2 to 8 carbon atoms) amine, mono, di, and trialkanol (2 to 8 carbon atoms) amine. Etc. When the copolymer of the present invention is used as a cement dispersant, it is preferably partially or completely neutralized. The salt of the copolymer in the present invention refers to a salt obtained by partially or completely neutralizing this acid type copolymer. The acid-type copolymer also includes a copolymer mixture obtained by using a salt as the monomer (b).

  The finally obtained copolymer of the present invention has an appropriate weight average molecular weight (gel permeation chromatography method (hereinafter referred to as “GPC method”), in terms of polyethylene glycol) in the range of 1,000 to 100,000. If it is out of this range, the water-reducing property is remarkably lowered, or a desired slump loss reducing effect cannot be obtained. More preferably, it is desirable that the weight average molecular weight is in the range of 5,000 to 30,000 in order to further exhibit water reduction. Further, in the aqueous solution polymerization, the molecular weight can be controlled by adjusting the kind and / or amount of the radical polymerization initiator used. Furthermore, it is possible to control the molecular weight distribution by using a chain transfer agent or the like in combination, but the content of polyalkylene glycol alkyl ether and unsaturated carboxylic acid with a reduced content ratio of the aforementioned alkylene oxide with a small number of added moles. It has been confirmed that the molecular weight distribution is narrowed by using the ester compound, and it is assumed that there is some relationship with the effect of the present invention. In the present invention, the “polymer” may be only the polymer itself, or includes components including unreacted components and side reaction products generated in each polymerization step, alkylene oxide addition step and the like. It may be a polymer in a broad sense.

  Examples of applications of the admixture for hydraulic compositions of the present invention include cement dispersants, various concrete product additives, grout additives, concrete repair material additives, gypsum board additives, hydraulic self-leveling. It can be used as an additive for cement and an additive for cement gypsum composite material.

  When the admixture for hydraulic composition of the present invention is used as a cement dispersant, it can be combined into a cement admixture by employing suitable publicly known admixtures according to various concrete production conditions. Specifically, cement dispersants other than the cement dispersant of the present invention, air entraining agents, setting retarders, accelerators, separation reducing agents, thickeners, antifoaming agents, shrinkage reducing agents, and the like. The cement dispersant made of the copolymer of the present invention is a form in which a publicly known admixture is blended in addition to the above-mentioned polycarboxylic acid polymer to form a cement admixture, or the above-mentioned polycarboxylic acid during concrete production. These include both of a system polymer and a publicly known admixture added separately and finally mixed in concrete. The publicly known admixtures are exemplified below.

  Generally, cement dispersants are appropriately combined and used according to concrete production conditions and performance requirements. The same applies to the cement dispersant of the present invention, which is used as a cement dispersant alone or as a main agent, but as a modification aid for a cement dispersant having a large slump loss, or has an initial water reduction. It can be used in combination as a high cement dispersant. As well-known cement dispersants other than the present invention, in addition to the above-mentioned Patent Document 1, Japanese Patent No. 2628486, Japanese Patent No. 2774445, Japanese Patent No. 323002, Japanese Patent No. 3336456, Japanese Patent No. 3780456, etc. There are also salts of polycarboxylic acid-based copolymers, and salts of naphthalene sulfonic acid formalin condensate, melamine sulfonic acid formalin condensate, lignin sulfonate, sodium gluconate, and sugar alcohol. The blending ratio of the cement dispersant of the present invention and the cement dispersant other than the present invention is 1:99 to 99: 1 mass%.

  Specific examples of the air entraining agent include <1> anionic air entraining agent, <2> nonionic air entraining agent, and <3> amphoteric air entraining agent. <1> As anionic air entraining agents, sulfuric acid ester salts of higher alcohols (or alkylene oxide adducts thereof), resin soap salts such as alkylbenzene sulfonates and rosin soaps, phosphoric acids of higher alcohols (or alkylene oxide adducts thereof) <2> Nonionic air entraining agents such as ester salts include alkylene glycol, alkylene oxide adducts of higher alcohols, esters of fatty acids and alkylene glycols, alkylene glycol adducts of sugar alcohols, <3> anions and cations Examples of the amphoteric air entraining agent comprising alkylbetaine type, alkylamide betaine type, and amino acid type amphoteric activator type. The preferred amount of addition of the air entraining agent is 0.001 to 0.03% by mass with respect to the cement dispersant.

  Examples of setting retarders include: <1> inorganic setting retarders: phosphates, silicofluorides, zinc oxide, zinc carbonate, zinc chloride, zinc monoxide, copper hydroxide, magnesia salts, borax, boron oxide <2> Organic coagulation retarders: phosphonic derivatives, saccharides and derivatives thereof, oxycarboxylates, lignin sulfonates, and more specific examples include phosphonic derivatives: aminotri (methylenephosphonic acid), aminotri (methylenephosphonic acid) ) Pentasodium salt, 1-hydroxyethylidene-1,1-diphosphonic acid, diethylenetriaminepenta (methylenephosphonic acid) and alkali metal salts, phosphonic acids of alkaline earth metal salts and derivatives thereof, saccharides: saccharose, maltose, raffinose, lactose Glucose, fructose, mannose, arabinose, key Loin, Abitosu, Repose, oxycarboxylate: gluconic acid, citric acid, glucoheptonic acid, malic acid, tartaric acid, their alkali metal salts, alkaline earth metal salts. A preferable addition amount of the setting retarder is 0.01 to 1.5% by mass with respect to a binding material such as cement.

  Examples of the accelerator include inorganic accelerators represented by calcium chloride, calcium nitrite and the like, and organic accelerators represented by alkanolamine and the like. A preferable addition amount of the accelerator is 0.5 to 5% by mass with respect to a binding material such as cement.

  Examples of thickeners / separation reducing agents include: <1> Cellulose-based water-soluble polymer: cellulose ether (MC, etc.), <2> Polyacrylamide-based water-soluble polymer: Polyacrylamide, <3> Biopolymer: Curdlan , Welan gum, <4> nonionic thickener: polyalkylene glycol fatty acid diester, polyalkylene glycol urethane condensate, and the like. A preferable blending ratio of the thickening / separation reducing agent is 0.01 to 0.5% by mass with respect to the concrete composition.

  Examples of antifoaming agents include nonionic defoaming agents such as aliphatic alcohol alkylene oxide adducts, fatty acid alkylene oxide adducts, alkylene oxide difatty acid esters, polyhydric alcohol alkylene oxide adducts, polyalkylene polyamine alkylene oxide adducts, etc. And silicone-based antifoaming agents using silicone oil as an emulsion, higher alcohols using higher alcohol as an emulsion, and mixtures containing these as main components. The preferable addition amount of this antifoaming agent is 0.001-1 mass% with respect to a cement dispersing agent.

  Examples of shrinkage reducing agents include polyalkylene glycols, lower alcohol alkylene oxide adducts, and emulsions when these are oily. The preferred addition amount is 0.1 to 5% by mass with respect to the binding material such as cement. is there.

Although the addition amount of the cement dispersant of the present invention varies depending on the blending conditions including the concrete material, it is generally added in an amount of about 0.05 to 5.0% by mass in terms of solid content with respect to the cement mass. In order to obtain water-reducing properties and slump flow retention, it is better that the amount added is larger. The method of use is the same as in the case of ordinary cement dispersants, and is added to the stock solution during concrete kneading or diluted in kneading water in advance. Alternatively, concrete or mortar may be added after kneading and kneaded uniformly again. Here, the components other than the cement dispersant are conventional concrete components, such as cement (for example, ordinary Portland cement, early strong Portland cement, low heat / moderate heat Portland cement or blast furnace cement), aggregate (that is, fine aggregate). And coarse aggregates), admixtures (for example, silica fume, calcium carbonate powder, blast furnace slag powder), expansion material and water. Moreover, as an admixture that can be added separately at the time of preparation with an admixture other than the cement dispersant of the present invention, the above-mentioned publicly known air entraining agent, setting retarder, accelerator, separation reducing agent, thickener, antifoaming agent, There are shrinkage reducing agents and the like, and these can be appropriately blended. The blending ratio of these components can be appropriately determined according to the type of the selected component and the purpose of use.

  Next, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In addition, unless otherwise indicated,% shown below represents mass%.

<Gas chromatography (GC) measurement conditions>
Apparatus: GC-2010, AOC-20i (manufactured by Shimadzu Corporation)
Column: DB-1701 (manufactured by J & W Scientific), length: 30.0 m, column oven: 170 ° C.
Carrier gas: He, total flow rate: 33.3 ml / min, injection volume: 0.8 μL
Temperature rising rate: 10 ° C./min, hold temperature / time: 170 ° C./17 min, 220 ° C./5 min, 280 ° C./15 min
Detector: FID, detector temperature: 300 ° C., vaporization chamber temperature: 280 ° C., air flow rate: 400 ml / min, hydrogen flow rate: 40 ml / min

<Measurement conditions for liquid chromatography (LC)>
Apparatus: LC20A (manufactured by Shimadzu Corporation)
Column: ODS column manufactured by Tosoh Corporation Mobile phase: water / methanol = 80 / 20-50 / 50 (vol%)
Detector: RID

<Gel permeation chromatography (GPC) measurement conditions>
Column: OHpak SB-802.5HQ, OHpak SB-803HQ, OHpak SB-804HQ (Showa Denko Co., Ltd.)
Eluent: 50 mM sodium nitrate aqueous solution and acetonitrile mixture (volume ratio 80/20)
Detector: differential refractometer, calibration curve: polyethylene glycol

<Production of polyethylene glycol monomethyl ether>
(Synthesis Example 1)
A stainless steel autoclave equipped with nitrogen and ethylene oxide introduction tubes was charged with 140 parts of methanol, and then with 0.10 parts of sodium methoxide. Thereafter, nitrogen substitution in the system was performed, 545 parts of ethylene oxide was introduced at a reaction temperature of 120 ° C., and then aging was performed at 125 ° C. for 45 minutes to obtain 678 parts of a polyethylene glycol monomethyl ether synthesis solution. By distilling the synthesis solution, a fraction having an added mole number of ethylene oxide of 3 mol or less was removed to obtain a compound a1. When the composition of this compound was measured by GC, the content of polyethylene glycol monomethyl ether having an ethylene oxide addition mole number of 3 mol or less was 0.5%. The average molecular weight was 230.

(Comparative synthesis example)
Under the same apparatus and reaction conditions as in Synthesis Example 1, 112 parts of methanol, 0.10 parts of sodium methoxide, and 573 parts of ethylene oxide were introduced to obtain 680 parts of a synthetic solution of polyethylene glycol monomethyl ether x1. When the composition of this compound was measured by GC, the content ratio of the number of moles of ethylene oxide added was 3 mol or less was 32.8%. The average molecular weight was 230.
In the same manner as x1, polyethylene glycol monomethyl ether x2 (average molecular weight 400) and x3 (average molecular weight 1,000) were obtained.

(Synthesis Example 2)
Ethylene oxide was added to the compound a1 using sodium methoxide as a catalyst in the same apparatus to obtain polyethylene glycol monomethyl ether a2. It was 400 when the molecular weight of this compound was calculated by measuring the hydroxyl value.

Here, the results of analyzing the addition mole number distribution of ethylene oxide of polyethylene glycol monomethyl ether x2 synthesized in Comparative Example Synthesis Example having the same average molecular weight and the same a2 synthesized in Synthesis Example 2 using LC are shown in FIG. It is shown in 1.
As shown in FIG. 1, it was confirmed that the polyethylene glycol monomethyl ether a2 had a narrower and sharper added mole number distribution than x2.

(Synthesis Example 3)
Synthesis and distillation were carried out using the same charge ratio of methanol and ethylene oxide as in Synthesis Example 1, the same apparatus and reaction conditions, and compound a3 was obtained. The content when the number of moles of ethylene oxide added was 3 mol or less was 3.6%, and the average molecular weight was 230 as measured by GC.

<Manufacture of monomer (a)>
Polyethylene glycol monomethyl ether (a1 to a3, x1 to x3) obtained in Synthesis Examples 1 to 3 or Comparative Synthesis Example and acrylic acid or methacrylic acid are subjected to dehydration ester by a conventional method, and methacrylic acid ester of polyethylene glycol monomethyl ether Alternatively, an acrylic ester was obtained.
In addition, it shows in Table 1 about the acrylic acid ester or methacrylic acid ester of the polyethyleneglycol monomethyl ether used for manufacture of the polymer mentioned later.

<Manufacture of other copolymerizable monomer (c)>
(Synthesis Example 4: Synthesis of monomers c1 and c2)
Using an apparatus similar to that described in Synthesis Example 1, ethylene oxide was added to methanol using sodium methoxide as a catalyst, and polyethylene glycol monomethyl ether (molecular weight: 1,000 and 2,000) was added. Obtained.
These were dehydrated and esterified with methacrylic acid in a conventional manner to obtain methoxypolyethylene glycol methacrylate (monomers c1 and c2).

(Synthesis Example 5: Synthesis of monomer c3)
Polyethylene glycol monomethyl ether having a molecular weight of 4,000 and methacrylic acid were dehydrated and esterified by a conventional method to obtain methoxypolyethylene glycol methacrylate (monomer c3).

(Synthesis Example 6: Synthesis of monomer c4)
In a reaction vessel equipped with a stirrer, 250 parts of polyalkylene polyamine “Polyate” (manufactured by Tosoh Corp.) and 86 parts of adipic acid were charged and stirred and mixed in a nitrogen atmosphere by introducing nitrogen. The temperature was raised to 150 ° C., and the reaction was allowed to proceed for 20 hours until the acid value reached 18 while expelling the dehydrated product produced by the condensation polymerization reaction out of the reaction system. Next, 1.7 parts of hydroquinone methyl ether and 2.5 parts of methacrylic acid were charged and reacted at the same temperature for 10 hours. As a result, 318 parts of polyamide polyamine were obtained together with a total of 21 parts of reaction distilled water. The total amount of this polyamide polyamine was dissolved in 414 parts of water and heated up to a temperature of 50 ° C. At the same temperature, 239 parts of ethylene oxide was sequentially introduced over 2 hours, and then aging was performed for 2 hours, to obtain 971 parts of a polyamide (polyamine ethylene oxide) adduct (monomer c4) as a target product.

(Monomer c5)
As the monomer c5, an ethylene oxide adduct (molecular weight: 1,200) of 3-methyl-3-buten-1-ol was used.

<Preparation of copolymers A1 to A9, B1 to B5, P1 to P4>
(Production Example 1: Preparation of copolymer A1)
A reaction vessel equipped with a nitrogen introduction tube, a stirrer, and a thermometer was charged with 330 parts of water, nitrogen was introduced, the inside of the reaction vessel was placed in a nitrogen atmosphere, and the temperature was raised to 80 ° C. Thereto, 308 parts of a methacrylic acid ester of polyethylene glycol monomethyl ether a1 and a mixed solution obtained by dissolving 76.8 parts of methacrylic acid in 87 parts of water, 63 parts of a 10% aqueous thioglycolic acid solution and 81 parts of an aqueous 10% sodium persulfate solution 3 liquids were dripped in reaction container over 3 hours. After completion of dropping, the mixture was aged at the same temperature for 2 hours, and then neutralized with sodium hydroxide to obtain 984 parts of copolymer A1. It was 6,800 when the weight average molecular weight (Mw) of the compound was measured by GPC.

  In the same process as the copolymer A1, copolymers A2 to A9, B1 to B5, and comparative copolymers P1 to P4 having the structures shown in Tables 1 to 2 were obtained. In addition, the number in the bracket | parenthesis in the component (A) of Table 1 shows the mass ratio of the (meth) acrylic acid ester of the methoxypolyethylene glycol used in the component (A).

<Preparation of Admixtures 1-20, Comparative Admixtures 1-4>
Table 3 shows the composition of the admixture prepared by blending each copolymer. The weight ratio described in Table 3 represents the solid content ratio of the copolymer.

≪Fresh concrete test≫
For the admixtures 1 to 20 in the above blending examples, a fresh concrete test was performed with the concrete blending shown in Table 4 below. For mixing concrete, use a 55 liter forced biaxial mixer, add each admixture (1-20) in advance to the coarse aggregate, cement, and fine aggregate, add the prepared water, and mix for a predetermined time. Went.
Then, immediately after the concrete is discharged, it corresponds to the slump test (JIS A 1101), the amount of air (JIS A 1128), and the setting test (the time until the mortar penetration resistance reaches 3.5 N / mm ² ) as a fresh concrete test. , This is the initial setting time), and concrete viscosity was evaluated.
≪Compressive strength test≫
The concrete immediately after the preparation in the section of the fresh concrete test was filled into a φ10 × 20 cm mold. Compressive strength was measured for 28 days in accordance with JIS A 1108 for specimens that were demolded and sealed for 28 days after sealing for one day.
≪Mortar viscosity evaluation≫
(Viscosity evaluation A: Flow time measurement)
The mortar produced by the formulation shown in Table 5 is filled in a funnel having an upper inner diameter of 70 mm, a lower inner diameter of 25 mm, and a height of 250 mm with a lid at the bottom, and the time from when the lid is removed until the mortar flows down (flowing time) ) Was measured. It can be evaluated that the shorter the flow down time, the better the workability. The results obtained are shown in Table 6.
(Viscosity evaluation B: 5-stroke flow measurement)
The mortar is filled into a mini slump cone having an upper inner diameter of 50 mm, a lower inner diameter of 100 mm, and a height of 150 mm, and the cone is pulled upward on a flow table used for a flow test specified in JIS R 5201, and the slump of the mortar is measured. (The one that was approximately 10 cm was used for subsequent tests). Thereafter, the slump flow of the mortar after hitting the flow table 5 times was measured. The results obtained are shown in Table 6.
It can be evaluated that the larger the value of the 5-stroke flow at the same slump value, the higher the deformability with respect to the load, that is, the lower the viscosity. Regarding the effectiveness of viscosity evaluation by this five-stroke flow measurement, Hiroshi Mori, Ikuo Tanikawa: Rheological consideration on various consistency test methods for fresh concrete, Japan Architectural Institute Structural Papers, No. 377, pp 16-26, 19877.7.

As shown in Table 6 above, Examples 1 to 20 using the admixture of the present invention are excellent in water reduction, have no setting delay, and the viscosity of fresh concrete is low and can be easily mixed. I understood.
On the other hand, Comparative Examples 1 to 4 using comparative admixtures are slightly inferior in water reduction and setting time, and the viscosity of fresh concrete, in particular, the viscosity after 30 minutes is high, resulting in poor workability. It was.

Claims (3)

A copolymer obtained by reacting the following monomers (a), (b) and, if necessary, (c) or a salt thereof, wherein the copolymerization ratio of the monomers (a) to (c) is mass (A) :( b) :( c) = 50-95%: 5-50%: 0-0-40% copolymer or salt thereof (A) and (a) :( b) :( c) An admixture for a hydraulic composition containing a copolymer or a salt thereof (B) of 0 to 45%: 5 to 30%: 30 to 90%.
(A) The following general formula (1):
R ¹ O— (AO) n—H (1)
(In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, A represents an alkylene group having 2 to 4 carbon atoms, n represents the number of added moles of alkylene oxide and represents an integer of 0 to 7) Represents.)
Ester obtained by adding 0 to 10 moles of alkylene oxide having 2 to 4 carbon atoms to 1 mole of at least one compound represented by formula (1) and further reacting the adduct with an α, β-unsaturated carboxylic acid However, as a compound represented by the formula (1), the content ratio of the compound having n of 3 or less based on the total mass of the compound represented by the formula (1) is 5% by mass or less. An ester compound obtained using a certain one,
(B) α, β-unsaturated carboxylic acid or salt thereof, and (c) other copolymerizable monomers A copolymer obtained by reacting the following monomers (a), (b) and, if necessary, (c) or a salt thereof, wherein the copolymerization ratio of the monomers (a) to (c) is mass (A) :( b) :( c) = 50-95%: 5-50%: 0-0-40% copolymer or salt thereof (A) and (a) :( b) :( c) An admixture for a hydraulic composition containing a copolymer or a salt thereof (B) of 0 to 45%: 5 to 30%: 30 to 90%.
(A) The following general formula (2):

(In the formula, R ² represents an alkyl group having 1 to 12 carbon atoms, R ³ represents a hydrogen atom or a methyl group, A represents an alkylene group having 2 to 4 carbon atoms, and m represents addition of an alkylene oxide. The number of moles represents an integer of 0 to 15.)
The content ratio of the compound having m of 3 or less in the compound is 5% by mass or less based on the total mass of the compound, and the average value of m is A compound that is 4.0-8.5,
(B) Copolymer or salt thereof obtained by reacting α, β-unsaturated carboxylic acid or a salt thereof, and (c) other copolymerizable monomer as required. The admixture for hydraulic composition according to claim 1 or 2, wherein the weight ratio of (A) to (B) is (A) / (B) = 1/99 to 99/1.

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