JP2001220416A - Polycarboxylic acid, method for producing the polycarboxylic acid and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polycarboxylic acid having a high ratio of a sufficiently high-molecular weight polymer part, capable of supplying a polymer, for example, suitable for a cement admixture. SOLUTION: The first method for producing a polycarboxylic acid comprises starting a polymerization by using hydrogen peroxide and an organic reducing agent in obtaining a polycarboxylic acid by copolymerizing a monomer component containing a polyalkylene glycol monoalkenyl ether monomer (I) and a maleic acid-based monomer (II) as essential components. The second method for producing the polycarboxylic acid comprises starting the polymerization within five hours from a point of time when the mixture of the polyalkylene glycol monoalkenyl ether monomer (I) and the maleic acid-based monomer starts in obtaining the polycarboxylic acid by copolymerizing the monomer component containing the polyalkylene glycol monoalkenyl ether monomer (I) and the maleic acid-based monomer (II) as essential components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polycarboxylic acid suitably used as a cement additive and the like, a method for producing the same, and a cement additive using the polycarboxylic acid.

[0002]

2. Description of the Related Art Conventionally, a polycarboxylic acid obtained by copolymerizing a monomer component containing a polyalkylene glycol monoalkenyl ether monomer (I) and a maleic acid monomer (II) as essential components has been known. Acid is known to exhibit excellent water reducing performance as a high performance AE (air entraining) water reducing agent, and is suitably used as a cement dispersant. However, such a polyalkylene glycol monoalkenyl ether monomer (I) and a maleic acid monomer (I
In the reaction system with (I), since the chain transfer property of the monomer is large, when reacted at a high temperature, although the polymerization rate of the monomer is high, the oligomer portion having a low degree of polymerization increases, and the performance as a cement dispersant increases. A problem is likely to occur in that the effective polymer portion having a high molecular weight that can be exerted is reduced. On the other hand, when the reaction is carried out at a low temperature, chain transfer of the monomer can be suppressed, so that a polycarboxylic acid having a small number of oligomer portions and a large number of effective polymer portions can be obtained. Rates tended to be lower.

In order to solve this problem, it is necessary to carry out the reaction at a low temperature when obtaining the polycarboxylic acid and to extend the reaction time in order to increase the polymerization rate of the monomer. If time is required, productivity and workability are poor, and there is a problem in cost for industrial implementation. Therefore, in the reaction system,
It is desired to use a polymerization initiator having high reactivity at a low temperature. As a conventional polymerization initiator, for example, persulfates such as ammonium persulfate and sodium persulfate are used. However, since these initiators generate sulfuric acid at the time of polymerization, they may be corroded in a stainless steel reactor, and a glass-lined reactor needs to be used. Glass-lined reactors have lower thermal conductivity than stainless steel reactors, are less efficient at heating and cooling, are more vulnerable to impact, and are more difficult to repair if the lining layer is cracked. There is a problem that maintenance is costly. Furthermore, when polycarboxylic acid is used as a cement additive, it is usually desirable to neutralize it after polymerization in order to facilitate handling,
In a polycarboxylic acid obtained using a persulfate as an initiator, a salt is likely to be generated during neutralization, and this salt may precipitate as crystals and cause various troubles.

As the polymerization initiator, in addition to the above-mentioned persulfate, for example, azo peroxides such as 2,2'-azobis-2-methylpropionamidine hydrochloride are known. When these are used as initiators, the problem of the reaction vessel when using the above-mentioned persulfate and the problem of crystal precipitation at the time of neutralization are solved, but azo peroxides generally have a long half-life. In order to increase the polymerization rate at a low temperature, a long reaction time was required. Even when an initiator having a long half-life at a low temperature is used as described above, by increasing the amount of the initiator, the amount of active radicals can be increased as a whole and the polymerization can proceed promptly. Because a large amount of unreacted initiator remains in the coalescence, it may cause a change with time during storage, or a treatment for inactivating a large amount of the remaining initiator may be required, or polymerization may rapidly occur. If the process proceeds, there is a problem that a large amount of heat is generated and there is a risk of explosion.

[0005] Among the azo peroxides, there are initiators which have a short half-life and can achieve a sufficient polymerization rate even at a low temperature. However, since the half-life is short, they are stored at a low temperature of, for example, 0 ° C. or lower, and It is necessary to work at room temperature carefully and in a short time, and there are difficulties in storage management such as the possibility of explosion due to impact or contamination of impurities, and there is a problem in industrial use. Met. On the other hand, when a monomer component containing a polyalkylene glycol monoalkenyl ether monomer (I) and a maleic acid monomer (II) as essential components is copolymerized to obtain a polycarboxylic acid, There is a problem that the polymer performance of the polycarboxylic acid obtained when industrially produced on an actual scale is inferior to the polycarboxylic acid obtained on a laboratory scale. That is, as the scale is increased, only a polycarboxylic acid having a low proportion of a polymer portion having a sufficiently high molecular weight is obtained, which may have a very significant effect on the performance of a polymer as a cement additive or the like.

[0006]

The problem to be solved by the present invention is that a special reactor is required, crystals are precipitated during neutralization, and it is difficult to store a polymerization initiator to be used. Or, without a large amount of unreacted initiator remaining in the obtained polymer, at a high polymerization rate, and by a short reaction, the ratio of the polymer portion sufficiently high molecular weight is high, for example, An object of the present invention is to provide a method for producing a polycarboxylic acid capable of obtaining a polymer suitable for a cement additive. Also, when manufactured on an actual scale,
It is an object of the present invention to provide a method for producing a polycarboxylic acid in which the ratio of a polymer portion having a sufficiently high molecular weight is high and a polymer suitable for, for example, a cement additive can be obtained.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies and experiments to solve the above problems, and as a result, have found that active radicals can be produced by mixing an organic reducing agent with hydrogen peroxide having a long half-life. It has been found that by using both of them, which can be efficiently generated and individually have good storage stability, it is possible to suppress the chain transfer of the monomer and increase the high molecular weight polymer portion. . In addition, as the inventor scales up,
The ratio of the polymer portion having a sufficiently high molecular weight in the obtained polycarboxylic acid is low because the polyalkylene glycol monoalkenyl ether monomer (I) is unstable under acidic conditions and decomposes with time. Was found to be easy to do. That is, usually, in the laboratory scale, the polymerization can be easily started within 30 minutes including the temperature adjustment from the input of the raw material, so that the polyalkylene glycol monoalkenyl ether monomer (I)
Decomposition is not a major problem, but on an actual scale, the amount of raw material charged is large and the time required from the start to the end of charging takes a long time, so the polyalkylene glycol monoalkenyl ether monomer (I) and the maleic acid monomer It takes a long time from the time when the compound (II) starts to be mixed to the time when the polymerization is started, and the decomposition of the polyalkylene glycol monoalkenyl ether-based monomer (I) proceeds more unexpectedly. From this fact, when the present inventors use the polyalkylene glycol monoalkenyl ether monomer (I) and the maleic acid monomer (II) in specific amounts or more, the two monomers have begun to be mixed. It has been found that keeping the time from the point in time to the start of polymerization within a certain time is important for suppressing the decomposition of the polyalkylene glycol monoalkenyl ether-based monomer (I) and increasing the high molecular weight polymer portion. Was.

The present invention has been completed based on the above findings. That is, the first method for producing a polycarboxylic acid according to the present invention comprises a monomer component containing the polyalkylene glycol monoalkenyl ether monomer (I) and the maleic acid monomer (II) as essential components. In obtaining the polycarboxylic acid by copolymerization, the polymerization is started using hydrogen peroxide and an organic reducing agent. In addition, the second method for producing a polycarboxylic acid according to the present invention includes a method for producing a polyalkylene glycol monoalkenyl ether monomer (I) and a maleic acid-based monomer (II) as essential components. In obtaining a polycarboxylic acid by copolymerization, polymerization is started within 5 hours from the time when the polyalkylene glycol monoalkenyl ether monomer (I) and the maleic acid monomer (II) are mixed. It is characterized by making it.

The first polycarboxylic acid according to the present invention comprises:
A polycarboxylic acid obtained by copolymerizing a monomer component containing a polyalkylene glycol monoalkenyl ether monomer (I) and a maleic acid monomer (II) as essential components. It is characterized by being obtained by initiating polymerization with an organic reducing agent. The second polycarboxylic acid according to the present invention is obtained by copolymerizing a monomer component containing a polyalkylene glycol monoalkenyl ether monomer (I) and a maleic acid monomer (II) as essential components. Wherein the polyalkylene glycol monoalkenyl ether monomer (I) and the maleic acid monomer (II) start to be polymerized within 5 hours from the start of mixing. It is characterized by being obtained by.

[0010] The cement additive according to the present invention comprises the first or second polycarboxylic acid of the present invention.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The monomer components to be copolymerized to produce a polycarboxylic acid according to the production method of the present invention include:
The polyalkylene glycol monoalkenyl ether monomer (I) and the maleic acid monomer (II) are contained as essential components. The polyalkylene glycol monoalkenyl ether monomer (I) used as one of the essential components of the monomer component is not particularly limited, but for example, a compound represented by the following general formula (1) is used. Is preferred.

[0012]

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(In the formula (1), R ₁ represents an alkenyl group having 2 to 5 carbon atoms, and R ₂ O represents one or a mixture of two or more oxyalkylene groups having 2 to 18 carbon atoms (2 even if the above species are added in a block state represents may) also be added to the random form, R ₃ is hydrogen or C 1 -C
Represents an hydrocarbon group of ３０30, and p is an average number of added moles of the oxyalkylene group, and represents a number of 1 to 300. In the general formula (1), R ₁ is an alkenyl group having 2 to 5 carbon atoms, and specific examples thereof include a vinyl group, an allyl group, a methallyl group, a 3-methyl-3-butenyl group, and a 3-methyl- 2
-Butenyl group, 1,1-dimethyl-2-propenyl group,
Examples include a 2-methyl-3-butenyl group and a 2-methyl-2-butenyl group. In the present invention, in particular, the use of the monomer (I) in which R ₁ is an alkenyl group having 5 carbon atoms in the general formula (1) has high polymerizability and a high molecular weight compound is easily obtained. Preferred for reasons. More preferably, in the general formula (1), R ₁ is preferably an alkenyl group represented by the following general formula (3).

[0014]

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(In the formula (3), R ₆ , R ₇ and R ₈ each independently represent hydrogen or a methyl group (provided that R ₆ or R ₈ and R ₇ are not simultaneously a methyl group. ),
R ₉ represents —CH ₂ —, — (CH ₂ ) ₂ — or —C (C
H ₃ ) ₂ — and R ₆ , R ₇ , R ₈ and R ₉
The total number of carbons in is always 3. In the general formula (1), R ₂ O represents one kind or a mixture of two or more kinds of oxyalkylene groups having 2 to 18 carbon atoms. It may be added. Specific examples thereof include an oxyethylene group, an oxypropylene group, an oxybutylene group, an oxytetramethylene group, an oxystyrene group, an oxydecylene group, an oxytetradecylene group, an oxyhexadecylene group, and an oxyoctadecylene group. Of these, an oxyalkylene group having 2 to 4 carbon atoms is particularly preferable.

In the general formula (1), R ₃ represents hydrogen or a hydrocarbon group having 1 to 30 carbon atoms, and specific examples thereof include hydrogen; methyl, ethyl, propyl, butyl, octyl, C1-C30 aliphatic alkyl group such as 2-ethyl-1-hexyl group, nonyl group, lauryl group, cetyl group, stearyl group; C3-C3 group such as cyclohexyl group
Alicyclic alkyl group of 0; phenyl group; alkyl group having a phenyl group such as phenylmethyl group (benzyl group); methylphenyl group, p-ethylphenyl group, dimethylphenyl group, pt-butylphenyl group, nonyl Alkylphenyl groups such as phenyl group and dodecylphenyl group; phenyl groups having a benzene ring such as biphenyl group and naphthyl group; and the like.

In the general formula (1), p is an average number of added moles of the oxyalkylene group, and represents 1 to 300. In particular,
When the polycarboxylic acid obtained by the production method of the present invention is used as a cement additive, in order to obtain high water reducing performance, the cement particles are sterically repelled by the polyalkylene glycol chain contained in the monomer (I) and hydrophilic. Is important. For that purpose, it is preferable that many oxyethylene groups are introduced into the polyalkylene glycol chain. Further, it is preferable to use a polyalkylene glycol chain having an average addition mole number of the oxyalkylene group of 1 to 300, but from the viewpoint of polymerizability and hydrophilicity, the average addition mole number of the oxyalkylene group is 2 to 300, preferably Is suitably a polyalkylene glycol chain of 5 to 200, more preferably 8 to 150. If the average number of moles of the oxyalkylene group exceeds 300, the polymerizability is undesirably reduced.

Specific examples of the monomer (I) include, but are not particularly limited to, for example, vinyl alcohol, allyl alcohol, methallyl alcohol, 3-methyl-3-buten-1-ol, and 3-methyl-2. -Buten-1-ol,
2-methyl-3-buten-2-ol, 2-methyl-2
-Buten-1-ol, 2-methyl-3-butene-1-
Examples thereof include compounds in which an alkylene oxide is added to an unsaturated alcohol such as an all in an amount of 1 to 300 moles on average, and one or more of these can be used. The maleic acid-based monomer (II) used as another essential component of the monomer component is not particularly limited, but for example, a compound represented by the following general formula (2) is preferably used. .

[0019]

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(In the formula (2), X is -OM_TwoOr -Y
− (R_FourO)_qR_FiveAnd M₁, M _TwoIs German
First, hydrogen, monovalent metal, divalent metal, ammonium group or
Represents an organic amino group, -Y- represents -O- or -NH
-Represents R_FourO is oxyalkylene having 2 to 18 carbon atoms
Or a mixture of two or more of these groups (in the case of two or more,
Even if it is added in a block shape, it is added in a random shape
Also good), R_FiveIs hydrogen, an alkyl having 1 to 30 carbon atoms
Kill group, phenyl group, aminoalkyl group, alkylphen
Nyl group or hydroxylalkyl group (aminoalkyl
Group, alkylphenyl group, hydroxylalkyl group
The alkyl group has 1 to 30 carbon atoms), and q is
The average number of moles of the added oxyalkylene group, from 0 to 30
Represents the number 0. Where M₁Is bonded to oxygen and X is
The bonded carbon is bonded to form an acid anhydride group (—CO—O
-CO-). In this case, M₁
And X do not exist. Examples of the maleic acid-based monomer are not particularly limited.
But not to mention maleic acid and its derivatives
And one or more of these can be used.
You. The maleic acid derivative is not particularly limited.
Is, for example, maleic anhydride; maleic acid and 1 to 1 carbon atoms
30 half esters with alcohol; maleic acid and
Half amides with amines having 1 to 30 carbon atoms; maleic
Half-amid of acid and amino alcohol having 1 to 30 carbon atoms
Or half-esters; charcoal in these alcohols
An average of 1 to 300 mol of oxyalkylene having a prime number of 2 to 18
Half ester of the added compound (C) and maleic acid
A compound wherein the hydroxyl group at one terminal of the compound (C) is aminated
Half amides of compounds with maleic acid; maleic acid
Glycols having 2 to 18 carbon atoms or their glycols
Polyalkylene glycos having an average addition mole number of 2 to 100
Ester with maleic acid; maleamic acid and carbon number 2-1
8 glycols or the average addition of these glycols
With polyalkylene glycol having 2 to 100 moles
Fuamides; and their monovalent metal salts, divalent metal salts,
Examples include ammonium salts and organic amine salts.
And one or more of these can be used.
You.

As the monomer component, the above-mentioned monomers (I) and (II) are always used.
Other monomers (III) copolymerizable with these monomers (I) and (II) may be used in combination with monomers (I) and (II). The monomer (III) is not particularly limited. For example, an unsaturated carboxylic acid monomer other than the maleic acid monomer can be used. Specifically, for example, unsaturated dicarboxylic acids such as fumaric acid, itaconic acid and citraconic acid; and monovalent metal salts thereof,
Divalent metal salts, ammonium salts, organic amine salts; and these acids and alkyl alcohols having 1 to 30 carbon atoms, glycols having 2 to 18 carbon atoms, or polyalkylene glycols having an average addition mole number of 2 to 100 of these glycols Monoesters or diesters of these; an alkylamine having 1 to 30 carbon atoms, an aminated compound of one end of a glycol having 2 to 18 carbon atoms, or a polyalkylene having an average addition mole number of 2 to 100 of these glycols Monoamides or diamides with an aminated product of glycol at one terminal; maleic acid and an alkyl alcohol having 1 to 30 carbon atoms, a glycol having 2 to 18 carbon atoms, or a polyalkylene glycol having an average addition mole number of 2 to 100 of these glycols; Diesters; maleic acid and carbon number 1
(Meth) acrylic acid with an alkylamine having an alkylamine of from 30 to 30 and an aminated compound of one end of a glycol having 2 to 18 carbon atoms, or an aminated product of one end of a polyalkylene glycol having an average addition mole number of 2 to 100 of these glycols; And monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts thereof; and these acids and alkyl alcohols having 1 to 30 carbon atoms and glycols having 2 to 18 carbon atoms. Or an ester of these glycols with a polyalkylene glycol having an average addition mole number of 2 to 100; and an aminated product of these acids and a glycol having 2 to 18 carbon atoms at one terminal, or an average addition mole number of these glycols of 2 Amides with an aminated polyalkylene glycol at one terminal of -100;
And the like, and one or more of these can be used.

The monomer (III) is not limited to the above-mentioned monomers, and includes, for example, unsaturated sulfonic acids such as sulfoethyl (meth) acrylate, 2-methylpropanesulfonic acid (meth) acrylamide, and styrenesulfonic acid; And monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts thereof; (meth) acrylamide,
Unsaturated amides such as (meth) acrylalkylamide;
One or more kinds of unsaturated amino compounds such as dimethylaminoethyl (meth) acrylate; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyls such as styrene;

The monomers (I) and (II) to be copolymerized
Weight ratio of (III) ((I) / (II) / (III))
Is not particularly limited, but is preferably (1 to 99) /
(99-1) / (0-50), more preferably (50)
-99) / (50-1) / (0-49), and more preferably (60-95) / (40-5) / (0-3)
0), and more preferably (70-95) / (30)
-5) / (0-10). In the present invention, if necessary, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid,
One or more chain transfer agents such as octyl thioglycolate, octyl 3-mercaptopropionate, and 2-mercaptoethanesulfonic acid can be used.

In the first production method of the present invention, it is important to start the polymerization using hydrogen peroxide and an organic reducing agent during the copolymerization reaction. By mixing hydrogen peroxide and an organic reducing agent, active radicals can be efficiently generated to improve the polymerization rate, and furthermore, the chain transfer of the monomer is suppressed to increase the high molecular weight polymer portion. be able to. In addition, since hydrogen peroxide and organic reducing agents are stored separately until used,
Good storage stability. The hydrogen peroxide may be used in any form, and can be used in an appropriate form depending on the polymerization method. In particular, from the viewpoint of easy handling, it is preferable to use the aqueous hydrogen peroxide solution.

The amount of the hydrogen peroxide to be used is preferably 0.01 to 30 mol%, more preferably 0.1 to 20 mol%, and most preferably the total amount of the polymerizable monomer. Is preferably 0.5 to 10 mol%. 0.0
If it is less than 1 mol%, unreacted monomers increase, while if it exceeds 30 mol%, a polycarboxylic acid having a large oligomer portion is obtained, which is not preferable.
The organic reducing agent is a reducing agent composed of one or more atoms selected from the group consisting of C, H, O, N, S, P, and halogen, or an alkali metal salt or an alkaline earth metal salt thereof. And preferably has at least one carbon atom in the molecule. Specifically, for example, amine compounds such as monoethanolamine, diethanolamine, triethanolamine, hydroxylamine, hydroxylamine hydrochloride, and hydrazine or salts thereof; alkali metal sulfites such as sodium sulfite, sodium hydrogen sulfite, and metabisulfite A lower oxide such as hypophosphorous acid, sodium hypophosphite, sodium hydrosulfite, sodium dithionite or a salt thereof; formaldehyde sodium sulfoxylate;
Hydroxymethanesulfinic acid sodium dihydrate -SH groups such as, -SO ₂ H group, -NHNH ₂ group, -COCH
An organic compound having a group such as an (OH) group or a salt thereof;
Invert sugars such as D-fructose and D-glucose; thiourea compounds such as thiourea and thiourea dioxide; and the like.

In the present invention, as the organic reducing agent,
In particular, an enediol group [-C (OH) = C (OH)-]
Containing compounds and derivatives thereof, substituted enediol groups [-
C (OH) = C (OZ)-]-containing compound (where Z is
Represents a monovalent metal, a divalent metal, an ammonium group or an organic amino group. ) Is preferably used from the viewpoint of reduction efficiency. Further, among these, in view of the fact that they are strong reducing agents and are easily available, compounds containing at least the structure represented by the following general formula (4), specifically, for example, L-ascorbic acid, L- -Sodium ascorbate, L-ascorbate, erythorbic acid, sodium erysorbate, erythorbic acid ester and the like are preferable. Among these, L-ascorbic acid and erythorbic acid are particularly preferred. One or more organic reducing agents can be used.

[0027]

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The amount of the organic reducing agent to be used is preferably 0.1 to 500 mol%, more preferably 1 to 200 mol%, most preferably 10 to 100 mol%, based on hydrogen peroxide. It is good to do. When the amount is less than 0.1 mol%, active radicals are not sufficiently generated, and the amount of unreacted monomers increases. On the other hand, when the amount exceeds 500 mol%, the remaining organic reducing agent does not react with hydrogen peroxide. Is undesirably increased. In the method for producing a polycarboxylic acid of the present invention, it is preferable that at least one of the hydrogen peroxide and the organic reducing agent is dropped into the reaction system. By introducing at least one of hydrogen peroxide and an organic reducing agent dropwise over a period of time,
Active radicals can always be supplied into the reaction system, and the amount of unreacted monomers can be reduced. Also, as long as one of the hydrogen peroxide and the organic reducing agent is charged by dropping, the other one may be charged by any method, for example, divided charging, batch charging, post-mixing and the like. A method may be used. In the copolymerization, the method of introducing the monomer component is not particularly limited. For example, any method such as dropping, divided charging, batch charging, and post-mixing may be used.

In the second production method of the present invention, within 5 hours from the time when the polyalkylene glycol monoalkenyl ether monomer (I) and the maleic acid monomer (II) start to be mixed. It is important that the polymerization be initiated. Thereby, decomposition of the polyalkylene glycol monoalkenyl ether-based monomer (I) can be suppressed, and a high molecular weight polymer portion can be increased. Here, specifically, the start of polymerization means a point in time at which the agent of the hydrogen peroxide and the organic reducing agent, which is later charged into the reaction system, is started to be charged. In the production method of the present invention, the decomposition rate of each monomer is, specifically, 0 to 10% by weight of the polyalkylene glycol monoalkenyl ether monomer (I) and the maleic acid monomer (II). Is preferably 0 to 1% by weight. In addition, each decomposition rate is a method similar to the method for measuring the polymerization rate of each raw material monomer described below, and the remaining amount of each raw material monomer before the start of polymerization is quantified, and the charging of each raw material monomer is performed. The rate of reduction from the amount is determined, and this is used as the decomposition rate of each raw material monomer.

In the second production method of the present invention, for example, the polyalkylene glycol monoalkenyl ether monomer (I) is used in an amount of 25 kg or more, preferably 250 kg or more, more preferably 1500 kg or more, and / or a maleic acid-based monomer. 12.5 kg or more of monomer (II),
Preferably 125 kg or more, more preferably 750 kg
It is effective in the case of using the above. In the method for producing a polycarboxylic acid of the present invention, the temperature during the
The temperature is preferably 5 ° C. or lower, more preferably 90 ° C.
C. or lower, most preferably 85.degree. C. or lower. Here, the temperature during the reaction refers to the temperature in the reaction system during the dropping and the temperature in the reaction system during the aging. If the temperature during the reaction exceeds 95 ° C., the oligomer component tends to increase, which is not preferable.

In the method for producing a polycarboxylic acid of the present invention, the polymerization method is not particularly limited, and a known method such as solution polymerization or bulk polymerization can be employed. In particular, solution polymerization is preferable in consideration of reaction control and ease of handling of the polymer. The solution polymerization can be carried out batchwise or continuously, and the solvent used in this case is water; alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol; ketone compounds such as acetone and methyl ethyl ketone; tetrahydrofuran, dioxane and the like. And the like, but from the solubility of the raw material monomers and the resulting polymer,
It is preferable to use at least one selected from the group consisting of water and a lower alcohol having 1 to 4 carbon atoms. Among them, it is more preferable to use water as a solvent in that the solvent removal step can be omitted.

When the polycarboxylic acid obtained in the present invention is used as a cement additive, it is preferable to carry out a copolymerization reaction using an aqueous solvent from the viewpoint of obtaining a polycarboxylic acid having a high water reducing property. . Here, the aqueous solvent is
In addition to water, it refers to a hydrophilic solvent that does not separate at 25 ° C. when mixed with water at a weight ratio of 1: 1 or a mixed solvent of this hydrophilic solvent and water. The hydrophilic solvent is not particularly limited, but includes, for example, one or more of the above-mentioned lower alcohols. In the production method of the present invention,
The polymerization rate of each raw material monomer can be determined by, for example, liquid chromatography (hereinafter, referred to as “LC”) under the following measurement conditions, and is preferably 80 to 100%, more preferably 85 to 100%, respectively. Most preferably 90-1
It is preferably in the range of 00%. Specifically, LC
By quantifying the residual amount of each raw material monomer, assuming that all the amount reduced from the charged amount of each raw material monomer was consumed in the polymerization, the weight loss rate of each raw material monomer was obtained, and this was calculated for each raw material monomer. The polymerization rate of the monomer is used.

<Conditions for Measurement of Polymerization Ratio> Model: Waters LCM1 Detector: Waters 410 Eluent: Type Acetonitrile / 0.1N acetic acid aqueous solution = 40/60 (wt%) pH 4.0 Flow rate 1.0 ml / min Column: Type GL Science Inc. Inertsil ODS-2 3 pieces 4.6 × 250 mm The polycarboxylic acid of the present invention is obtained by the above-mentioned production method, and has a characteristic that the ratio of the polymer portion having a sufficiently high molecular weight is high. Things. For example, in the polycarboxylic acid of the present invention, the content ratio of a polymer component of a trimer or more is preferably 50 to 100%, more preferably 60 to 95%. The content ratio of the trimer or higher polymer component can be determined, for example, as follows from a GPC chart obtained by GPC under the same conditions as the following weight average molecular weight measurement conditions. That is, a peak corresponding to the molecular weight of the polyalkylene glycol monoalkenyl ether monomer (I) is defined as a peak A, and the peak A
After that, the peak on the polymer side is defined as a peak B, and all peaks on the polymer side relative to the peak B are defined as a peak C, and the respective peak areas are obtained and calculated by the following equation. Trimeric or higher polymer component (%) = [Peak C area /
(Area of peak A + Area of peak B + Area of peak C)] × 1
The weight average molecular weight of the polycarboxylic acid of the present invention is, for example,
It is preferably 5,000 to 200,000 in terms of polyethylene glycol by gel permeation chromatography (hereinafter, referred to as “GPC”) under the following measurement conditions.
It is preferably in the range of 0, more preferably 5,000 to 100,000, most preferably 8,000 to 100,000.

<Weight average molecular weight measurement conditions> Model: Waters LCM1 Detector: Waters 410 Eluent: type Acetonitrile / water = 40/60 Vol% pH 6.0 Flow rate 0.6 ml / min Column: Type TSK-manufactured by Tosoh Corporation GEL G4000SWXL + G3000SWXL + G2000SWXL + GUARD COLUMN 7.8 × 300 mm, 6.0 × 40 mm Calibration curve: polyethylene glycol standard The cement additive of the present invention comprises the polycarboxylic acid of the present invention. By including the polycarboxylic acid having the property that the ratio of the polymer portion having a sufficiently high molecular weight is high, the cement additive of the present invention can exhibit excellent water reducing performance.

The cement additive of the present invention is preferably used as an active ingredient of the cement additive in a cement composition containing at least cement, water and a cement additive. At that time, the obtained polycarboxylic acid can be used as it is, but if necessary, may be used after neutralization with an alkaline substance. Such alkaline substances are not particularly limited, but include, for example, hydroxides of alkali metals and alkaline earth metals such as sodium hydroxide, potassium hydroxide, calcium hydroxide and lithium hydroxide; sodium carbonate, calcium carbonate ,
Carbonates of alkali metals and alkaline earth metals such as lithium carbonate; ammonia; amines such as monoethanolamine, diethanolamine and triethanolamine; and one or more of these can be used.

Further, the cement additive of the present invention may contain the above-mentioned polycarboxylic acid dissolved in a solvent, if necessary. The solvent that can be used is not particularly limited, and examples thereof include water, alcohol, and a mixed solvent thereof. Among these, water is preferred from the viewpoint of safety, ease of handling, and the like. The cement additive of the present invention,
It can be used as it is as a main component of the cement additive, or may be used in combination with another known cement admixture. Such known cement admixtures include, for example, conventional cement dispersants, air entrainers, cement wetting agents, swelling agents, waterproofing agents, retarders, quick-setting agents, water-soluble polymer substances, thickeners, Examples thereof include a flocculant, a drying shrinkage reducing agent, a strength enhancer, a curing accelerator, and an antifoaming agent.

[0037]

The present invention will be described more specifically with reference to examples and comparative examples below, but the present invention is not limited to these examples. In the examples, unless otherwise specified, "%"
Represents "% by weight". In the following examples, the weight average molecular weight of the polycarboxylic acid is a value in terms of polyethylene glycol obtained by GPC under the above-described measurement conditions, and the polymerization rate of each raw material monomer is determined by LC under the above-described measurement conditions by the above-described method. The content ratio of the trimer or higher polymer component was determined by GPC under the measurement conditions described above by the method described above, and the decomposition rate of each monomer before the start of polymerization was determined by the aforementioned method. It is determined by the method.

Example 1 In a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube and a reflux condenser, 546 g of ion-exchanged water and 3-methyl-3-buten-1-ol were added. 800 g of a polyalkylene glycol monoalkenyl ether monomer (hereinafter, referred to as IPN-50) obtained by adding 50 mol of ethylene oxide, and 83 g of maleic acid (hereinafter, referred to as MA) are charged in a lump, and heated to 65 ° C. After the temperature was raised, 2.4 g of a 30% aqueous solution of hydrogen peroxide was added. There, 39.1g of ion exchange water
An aqueous solution of 0.9 g of L-ascorbic acid dissolved in
Dropped in time. At this time, after charging IPN-50 and MA (after starting mixing IPN-50 and MA)
It took less than 30 minutes until the aqueous L-ascorbic acid solution was introduced. Thereafter, the mixture was aged at 65 ° C. for 1 hour to complete the polymerization reaction. And 30% of this reaction solution
Was adjusted to pH 8 with an aqueous solution of sodium hydroxide to obtain an aqueous solution of a polycarboxylic acid. Table 1 shows the weight average molecular weight of the aqueous solution of the obtained polycarboxylic acid, the polymerization rate of each raw material monomer (IPN-50 and MA), and the content ratio of the polymer component of trimer or more.

<Embodiment 2> An apparatus similar to that of Embodiment 1
Each raw material was charged in the same manner as in Example 1 except that a hydrogen peroxide solution was added after the temperature was raised to 0 ° C. The L-ascorbic acid aqueous solution was dripped there similarly to Example 1. At this time, after charging IPN-50 and MA, (I
It took less than 30 minutes before the aqueous solution of L-ascorbic acid was added (after mixing PN-50 and MA was started). Thereafter, aging was continued at 50 ° C. for 1 hour to complete the polymerization reaction. Then, the pH of the reaction solution was adjusted in the same manner as in Example 1 to obtain an aqueous solution of a polycarboxylic acid. Table 1 shows the weight average molecular weight of the aqueous solution of the obtained polycarboxylic acid, the polymerization rate of each raw material monomer (IPN-50 and MA), and the content ratio of the polymer component of trimer or more.

<Comparative Example 1> In the same apparatus as in Example 1, each raw material was charged in the same manner as in Example 1, heated to 65 ° C, and then 2.4 g of a 30% aqueous solution of hydrogen peroxide was added. did.
An aqueous solution obtained by dissolving 2.1 g of Mohr's salt (iron (II) sulfate ammonium hexahydrate) in 37.9 g of ion-exchanged water was added dropwise thereto over 1 hour. At this time, it was within 30 minutes from charging IPN-50 and MA (after mixing IPN-50 and MA was started) to charging the Mohr salt aqueous solution. Thereafter, the mixture was aged at 65 ° C. for 1 hour to complete the polymerization reaction. Then, the pH of the reaction solution was adjusted in the same manner as in Example 1 to obtain an aqueous solution of a polycarboxylic acid for comparison. Table 1 shows the weight average molecular weight of the aqueous solution of the obtained polycarboxylic acid, the polymerization rate of each raw material monomer (IPN-50 and MA), and the content ratio of the polymer component of trimer or more.

Comparative Example 2 In the same apparatus as in Example 1, 589 g of ion-exchanged water, 800 g of IPN-50, and MA8
3 g were charged all at once, and the temperature was raised to 60 ° C. There,
2,2′-azobis-2-methylpropionamidine hydrochloride (trade name “NC-32W” manufactured by Nippo Chemical Co., Ltd.)
2.89 g was added all at once, and the mixture was stirred for 10 hours to complete the polymerization reaction. At this time, after charging IPN-50 and MA into the reaction vessel (after starting mixing IPN-50 and MA), and before charging 2,2′-azobis-2-methylpropionamidine hydrochloride, It was within 30 minutes. Then, the pH of the reaction solution was adjusted in the same manner as in Example 1 to obtain an aqueous solution of a polycarboxylic acid for comparison. Table 1 shows the weight average molecular weight of the aqueous solution of the obtained polycarboxylic acid, the polymerization rate of each raw material monomer (IPN-50 and MA), and the content ratio of the polymer component of trimer or more.

[0042]

[Table 1]

As is clear from Table 1, in Examples 1 and 2, the polycarboxylic acid aqueous solution having a high weight-average molecular weight and a high content ratio of a polymer component of trimer or higher was high in both cases. And with a short reaction time. In particular, in Example 2, since the dropping and aging were performed at a lower temperature than in Example 1, a polycarboxylic acid aqueous solution having a higher molecular weight than that of Example 1 was obtained. On the other hand, in Comparative Example 1 using the metal-based reducing agent, the polymerization rate of each raw material was low, and the content ratio of the trimer or higher polymer component in the obtained aqueous polycarboxylic acid solution was also low. In Comparative Example 2,
Example 1 because an azo peroxide was used as the polymerization initiator.
3 times or more of the reaction time was required.

Example 3 In a 15 m ³ stainless steel reactor equipped with a thermometer, a stirrer, a material charging nozzle, a nitrogen line and a condenser, 5460 kg of ion-exchanged water, M
A830 kg was charged, and the temperature was raised to 65 ° C. 6 reactors
While keeping the temperature at 5 ° C., 8000 kg of IPN-50 was added to 1.
Charge over 5 hours, then add 30% aqueous hydrogen peroxide solution 2
4 kg were added. From the start of IPN-50 introduction (IP
After 2 hours (after the mixing of N-50 and MA was started), an aqueous solution in which 9 kg of L-ascorbic acid was dissolved in 391 kg of ion-exchanged water was added dropwise over 1 hour.
The polymerization was completed by aging at 1 ° C. for 1 hour. The reaction solution was adjusted to pH 8 with a 49% aqueous sodium hydroxide solution to obtain an aqueous polycarboxylic acid solution. The weight average molecular weight of the obtained polycarboxylic acid, the polymerization rate of each raw material monomer (IPN-50 and MA), the content ratio of the polymer component of trimer or more, and each monomer (IPN- 50 and MA) are shown in Table 2.

Example 4 The same apparatus as in Example 3 was charged with 5460 kg of ion-exchanged water and 830 kg of MA.
The temperature was raised to 0 ° C. 800 with the reactor kept at 60 ° C
0 kg of IPN-50 was charged over 1.5 hours, and then 24 kg of a 30% aqueous hydrogen peroxide solution was added. IPN
Two hours after the start of the introduction of -50 (after mixing IPN-50 and MA), 391 kg of deionized water was added to L-
An aqueous solution in which 9 kg of ascorbic acid was dissolved was added dropwise over 1 hour, and then the mixture was aged at 60 ° C. for 1 hour to complete the polymerization. Then, this reaction solution was added to p in the same manner as in Example 3.
By adjusting H, a polycarboxylic acid aqueous solution was obtained. The weight average molecular weight of the obtained polycarboxylic acid and each raw material monomer (IPN
-50 and MA), the content ratio of the polymer component of trimer or more, and each monomer (IPN-5) before the start of polymerization.
0 and MA) are shown in Table 2.

<Example 5> The same apparatus as in Example 3 was charged with 5460 kg of ion-exchanged water and 830 kg of MA.
The temperature was raised to 0 ° C. 800 with the reactor kept at 60 ° C
0 kg of IPN-50 was charged over 2.5 hours, and then 24 kg of a 30% hydrogen peroxide aqueous solution was added. IPN
3 hours after the start of the introduction of -50 (after mixing IPN-50 and MA started), 391 kg of ion-exchanged water was added to L-
An aqueous solution in which 9 kg of ascorbic acid was dissolved was added dropwise over 1 hour, and then the mixture was aged at 60 ° C. for 1 hour to complete the polymerization. Then, this reaction solution was added to p in the same manner as in Example 3.
By adjusting H, a polycarboxylic acid aqueous solution was obtained. The weight average molecular weight of the obtained polycarboxylic acid and each raw material monomer (IPN
-50 and MA), the content ratio of the polymer component of trimer or more, and each monomer (IPN-5) before the start of polymerization.
0 and MA) are shown in Table 2.

Example 6 The same apparatus as in Example 3 was charged with 5460 kg of ion-exchanged water and 830 kg of MA.
The temperature was raised to 0 ° C. 800 with the reactor kept at 60 ° C
0 kg of IPN-50 is charged over 4 hours, then 3 kg
24 kg of a 0% aqueous hydrogen peroxide solution was added. IPN-5
After 5 hours from the start of the injection of 0 (after mixing IPN-50 and MA was started), an aqueous solution in which 9 kg of L-ascorbic acid was dissolved in 391 kg of ion-exchanged water was added dropwise over 1 hour. It was aged for 1 hour to complete the polymerization. Then, the reaction solution was adjusted to pH as in Example 3.
After adjustment, a polycarboxylic acid aqueous solution was obtained. The weight average molecular weight of the obtained polycarboxylic acid and each raw material monomer (IPN-
50 and MA), the content ratio of the polymer component of trimer or more, and each monomer (IPN-50) before the start of polymerization.
And MA) are shown in Table 2.

Example 7 The same apparatus as in Example 3 was charged with 5460 kg of ion-exchanged water and 830 kg of MA.
The temperature was raised to 0 ° C. 800 with the reactor kept at 60 ° C
0 kg of IPN-50 is charged over 5 hours, then 3 kg
24 kg of a 0% aqueous hydrogen peroxide solution was added. IPN-5
7 hours after the start of the introduction of 0 (after mixing IPN-50 and MA was started), an aqueous solution in which 9 kg of L-ascorbic acid was dissolved in 391 kg of ion-exchanged water was added dropwise over 1 hour. It was aged for 1 hour to complete the polymerization. Then, the reaction solution was adjusted to pH as in Example 3.
After adjustment, a polycarboxylic acid aqueous solution was obtained. The weight average molecular weight of the obtained polycarboxylic acid and each raw material monomer (IPN-
50 and MA), the content ratio of the polymer component of trimer or more, and each monomer (IPN-50) before the start of polymerization.
And MA) are shown in Table 2.

[0049]

[Table 2]

From Table 2, it can be seen that as the time from the start of mixing IPN-50 and MA to the start of polymerization becomes longer, the decomposition rate of each monomer before polymerization increases, and the It is clear that the content ratio and the weight average molecular weight of the trimer or higher polymer component in the aqueous acid solution are reduced.

[0051]

According to the present invention, a special reactor is required, crystals are precipitated during neutralization, it is difficult to store a polymerization initiator to be used, With a high polymerization rate, without much unreacted initiator remaining
In addition, a polycarboxylic acid having a sufficiently high polymer portion ratio can be obtained by a short reaction time. Moreover, according to the present invention, even in the case of production on a large scale, a polycarboxylic acid having a high ratio of a polymer portion having a sufficiently high molecular weight can be obtained. In addition, this can provide a cement additive that can exhibit excellent water reducing performance.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08F 222/00 C08F 222/00 // C04B 103: 30 C04B 103: 30 (72) Inventor Hiromichi Tanaka Osaka 5-8 Nishiburi-cho, Suita City Nippon Shokubai Co., Ltd. (72) Inventor Eriko Maeda 5-8 Nishi-Maburicho, Suita City, Osaka Nippon Shokubai Co., Ltd.

Claims (12)

[Claims] A polycarboxylic acid is obtained by copolymerizing a monomer component containing a polyalkylene glycol monoalkenyl ether monomer (I) and a maleic acid monomer (II) as essential components. A method for producing a polycarboxylic acid, wherein polymerization is initiated using hydrogen oxide and an organic reducing agent. 2. The polyalkylene glycol monoalkyl
As the phenyl ether monomer (I), the following general formula (1)
And using the maleic acid-based monomer (I
As the I), a compound represented by the following general formula (2) is used.
A method for producing the polycarboxylic acid according to claim 1. Embedded image(In the formula (1), R₁Represents an alkenyl group having 2 to 5 carbon atoms
Represents, R_TwoO is an oxyalkylene group having 2 to 18 carbon atoms
Or a mixture of two or more (in the case of two or more,
It can be added in the form of a lock or in the form of a random
I) and R_ThreeIs hydrogen or carbonized carbon having 1 to 30 carbon atoms.
Represents a hydrogen group, and p is an average addition mode of the oxyalkylene group.
And represents a number from 1 to 300. )(In the formula (2), X is -OM_TwoOr -Y- (R_FourO)
_qR_FiveAnd M₁, M _TwoIs independently hydrogen,
Monovalent metal, divalent metal, ammonium group or organic amino
Represents a group, -Y- represents -O- or -NH-, and R
_FourO is at least one oxyalkylene group having 2 to 18 carbon atoms.
Or a mixture of two or more (in the case of two or more
May be added or may be added randomly).
Then R_FiveRepresents hydrogen, an alkyl group having 1 to 30 carbon atoms,
Nil group, aminoalkyl group, alkylphenyl group or
Hydroxyl alkyl group (aminoalkyl group, alkyl
Of alkyl group in phenyl group and hydroxylalkyl group
And q represents oxyalkyl.
It is the average number of added moles of the len group.
You. Where M₁Is bonded to oxygen and X is bonded to
An acid anhydride group (—CO—O—CO—)
Including those that constitute. In this case, M₁And X are
not exist. ) 3. As the organic reducing agent, a compound containing an enediol group [-C (OH) = C (OH)-] and a derivative thereof, and a substituted enediol group [-C (OH) = C (O
Z)-]-containing compound (wherein, Z represents one or more selected from the group consisting of monovalent metals, divalent metals, ammonium groups and organic amino groups). A method for producing a polycarboxylic acid. 4. A polyalkylene glycol monoalkenyl ether monomer (I) wherein, among the compounds represented by the general formula (1), compounds wherein R ¹ is an alkenyl group having 5 carbon atoms. 4. The method for producing a polycarboxylic acid according to 2 or 3. 5. The method for producing a polycarboxylic acid according to claim 1, wherein at least one of the hydrogen peroxide and the organic reducing agent is dropped into the reaction system. 6. A method for producing a polycarboxylic acid by copolymerizing a monomer component containing a polyalkylene glycol monoalkenyl ether monomer (I) and a maleic acid monomer (II) as essential components. A method for producing a polycarboxylic acid, wherein the polymerization is started within 5 hours from the time when the polyalkylene glycol monoalkenyl ether monomer (I) and the maleic acid monomer (II) are mixed. 7. The polyalkylene glycol monoalkenyl ether monomer (I) is at least 25 kg, and / or the maleic acid monomer (II) is 12.5 kg.
The method for producing a polycarboxylic acid according to claim 6, which is used as described above. 8. The polyalkylene glycol monoalkyl
As the phenyl ether monomer (I), the following general formula (1)
And using the maleic acid-based monomer (I
As the I), a compound represented by the following general formula (2) is used.
A method for producing the polycarboxylic acid according to claim 6. Embedded image(In the formula (1), R₁Represents an alkenyl group having 2 to 5 carbon atoms
Represents, R_TwoO is an oxyalkylene group having 2 to 18 carbon atoms
Or a mixture of two or more (in the case of two or more,
It can be added in the form of a lock or in the form of a random
I) and R_ThreeIs hydrogen or carbonized carbon having 1 to 30 carbon atoms.
Represents a hydrogen group, and p is an average addition mode of the oxyalkylene group.
And represents a number from 1 to 300. )(In the formula (2), X is -OM_TwoOr -Y- (R_FourO)
_qR_FiveAnd M₁, M _TwoIs independently hydrogen,
Monovalent metal, divalent metal, ammonium group or organic amino
Represents a group, -Y- represents -O- or -NH-, and R
_FourO is at least one oxyalkylene group having 2 to 18 carbon atoms.
Or a mixture of two or more (in the case of two or more
May be added or may be added randomly).
Then R_FiveRepresents hydrogen, an alkyl group having 1 to 30 carbon atoms,
Nil group, aminoalkyl group, alkylphenyl group or
Hydroxyl alkyl group (aminoalkyl group, alkyl
Of alkyl group in phenyl group and hydroxylalkyl group
And q represents oxyalkyl.
It is the average number of added moles of the len group.
You. Where M₁Is bonded to oxygen and X is bonded to
An acid anhydride group (—CO—O—CO—)
Including those that constitute. In this case, M₁And X are
not exist. ) 9. The polyalkylene glycol monoalkenyl ether monomer (I) is a compound represented by the general formula (1) wherein R ¹ is an alkenyl group having 5 carbon atoms. 9. The method for producing a polycarboxylic acid according to any one of 6 to 8. 10. A polyalkylene glycol monoalkenyl ether monomer (I) and a maleic acid monomer (II)
A polycarboxylic acid obtained by copolymerizing a monomer component containing as an essential component, characterized by being obtained by initiating polymerization using hydrogen peroxide and an organic reducing agent. Polycarboxylic acid. 11. A polyalkylene glycol monoalkenyl ether monomer (I) and a maleic acid monomer (II)
And a polycarboxylic acid obtained by copolymerizing a monomer component containing as an essential component, the polyalkylene glycol monoalkenyl ether monomer (I) and the maleic acid monomer (II) 5 from the beginning of mixing
A polycarboxylic acid obtained by initiating polymerization within an hour. 12. A cement additive comprising the polycarboxylic acid according to claim 10 or 11.