JPH09286645A - Cement admixture and cement composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve slump retentivity by incorporating two kinds of specified polyethylene glycol (meth)acrylates and a carboxylic acid polymer (salt). SOLUTION: Five to 90wt.% polyethylene glycol (meth)acrylate represented by formula I (where R1 is H or methyl, R2 O is oxymethylene, R3 is H or 1-22C alkyl and (m) is 1-97 as the average mol number of added R2 O) and 5-90wt.% polyethylene glycol (meth)acrylate represented by formula II (where R4 is R1 , R5 O is R2 O, R6 is R3 , (n) is 4-10 as the average mol number of added R5 O, n≠m and n-m>=3) are blended with a copolymer of 5-90wt.% carboxylic acid monomer represneted by formula III (where R7 is R1 and M1 is H, a monovalent metallic atom, a divalent metallic atom, ammonium or an org. amine) with 0-50wt.% monomer copolymerizable with the carboxylic acid monomer or a copolymer salt obtd. by neutralizing the copolymer with an alkaline material so that the total amt. is regulated to 100wt.%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cement admixture and a cement composition. More specifically, in a so-called cement mixture such as cement paste, mortar or concrete, the present invention relates to a slump holding type cement admixture that prevents the fluidity of the cement mixture from decreasing with time, and a cement composition containing the cement admixture. .

[0002]

2. Description of the Related Art Since the early deterioration of concrete structures became a social problem in 1981, it has been strongly demanded to reduce the amount of unit water in concrete to improve its workability and durability. Technological innovations are being actively carried out on cement dispersants that greatly affect the quality and performance of cement.

As a conventional method, an AE agent or AE is used.
Fluidity with a water reducing agent (hereinafter referred to as "slump")
A low fluidity concrete was manufactured in a plant, transported to a construction site by a ready-mixed concrete truck, and then a fluidizing agent was added to fluidize it to fluidize it to raise the slump to a predetermined value. . However, this construction method includes environmental problems such as noise and exhaust gas generated when a fluidizing agent is added to concrete by stirring with a ready-mixed concrete truck, the responsibility of the quality of the fluidized concrete obtained, the fluidized concrete. There were various problems such as a remarkable deterioration of the slump with time.

Therefore, so-called high-performance AE water-reducing agents that can be added in raw plants have been vigorously developed by each admixture manufacturer, and at present, naphthalene-based, aminosulfonic acid-based and polycarboxylic acid-based agents are commercially available. . Among them, the polycarboxylic acid type high-performance AE water reducing agent has an excellent feature that the highest water reducing rate can be obtained.
Under severe conditions of use such as transporting the obtained fresh concrete to a remote place in the summer, there is a problem that the slump loss may not be sufficiently suppressed, like other high performance AE water reducing agents.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a cement admixture having excellent slump retention and a cement composition containing the cement admixture.

[0006]

[Means for Solving the Problems] The above-mentioned object is as follows (1)
(7) is achieved.

(1) General formula (1)

[0008]

Embedded image

(In the formula, R1 represents a hydrogen atom or a methyl group, R2 O represents an oxyethylene group, and R3 represents
Is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, m is the average number of added moles of an oxyethylene group, and represents an integer of 1 to 97. ) The first polyethylene glycol (meth) acrylate (a) 5-9
0% by weight, general formula (2)

[0010]

Embedded image

(In the formula, R4 represents a hydrogen atom or a methyl group, R5 O represents an oxyethylene group, and R6 represents
Is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, n is the average number of added moles of an oxyethylene group, represents an integer of 4 to 100, and n ≠ m and n−m ≧ 3.
It is. ) 2nd polyethylene glycol (meth) acrylate (b) 5 to 90% by weight, represented by the general formula (3)

[0012]

[Chemical 12]

(In the formula, R7 represents a hydrogen atom or a methyl group, M1 represents a hydrogen atom, a monovalent metal atom, a divalent metal atom, an ammonium group or an organic amine group.)
A carboxylic acid-based monomer (c) represented by
And 0 to 50% by weight of another monomer (d) copolymerizable with these monomers (provided that (a), (b),
The sum of (c) and (d) is 100% by weight. ) The first copolymer (A) and / or the first copolymer salt (B) obtained by further neutralizing the first copolymer (A) with an alkaline substance. A cement admixture with excellent slump retention.

(2) General formula (1)

[0015]

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(Wherein R 1 represents a hydrogen atom or a methyl group, R 2 O represents an oxyethylene group, and R 3
Is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, m is the average number of added moles of an oxyethylene group, and represents an integer of 1 to 97. ) The first polyethylene glycol (meth) acrylate (a) 5-6
5% by weight, general formula (3)

[0017]

Embedded image

(In the formula, R7 represents a hydrogen atom or a methyl group, M1 represents a hydrogen atom, a monovalent metal atom, a divalent metal atom, an ammonium group or an organic amine group.)
35 to 95% by weight of the carboxylic acid-based monomer (c) represented by the formula (1) and 0 to 50% by weight of another monomer (d) copolymerizable with these monomers (provided that (a), ( The total amount of (c) and (d) is 100% by weight, and the second copolymer (A1) and / or the copolymer (A1) derived in a ratio of 100% by weight is further neutralized with an alkaline substance. The obtained second copolymer salt (B1) and the general formula (2)

[0019]

Embedded image

(In the formula, R4 represents a hydrogen atom or a methyl group, R5 O represents an oxyethylene group, and R6 represents
Is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, n is the average number of added moles of an oxyethylene group, represents an integer of 4 to 100, and n ≠ m and n−m ≧ 3.
It is. ) The second polyethylene glycol (meth) acrylate (b) 65 to 95% by weight, represented by the general formula (3)

[0021]

Embedded image

(In the formula, R7 represents a hydrogen atom or a methyl group, M1 represents a hydrogen atom, a monovalent metal atom, a divalent metal atom, an ammonium group or an organic amine group.)
A carboxylic acid-based monomer (c) represented by
And a ratio of 0 to 50% by weight of the other monomer (d) copolymerizable with these monomers (however, the total of (b), (c) and (d) is 100% by weight). The main component is a mixture of the third copolymer (A2) derived in (1) and / or the third copolymer salt (B2) obtained by further neutralizing the copolymer (A2) with an alkaline substance. A cement admixture with excellent slump retention.

(3) The copolymer (salt) (A1 and / or B1) and the copolymer (salt) (A2 and / or
Alternatively, the cement admixture according to the above (2), wherein the weight ratio of B2) is 1:99 to 99: 1.

(4) General formula (1)

[0025]

Embedded image

(In the formula, R1 represents a hydrogen atom or a methyl group, R2 O represents an oxyethylene group, and R3 represents
Is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, m is the average number of added moles of an oxyethylene group, and represents an integer of 1 to 97. ) The first polyethylene glycol (meth) acrylate (a) 5-6
5% by weight, general formula (3)

[0027]

Embedded image

(In the formula, R7 represents a hydrogen atom or a methyl group, M1 represents a hydrogen atom, a monovalent metal atom, a divalent metal atom, an ammonium group or an organic amine group.)
35 to 95% by weight of the carboxylic acid-based monomer (c) represented by and other monomer (d) copolymerizable with these monomers (provided that (a), (c) and (d) The total amount of () is 100% by weight.) The second copolymer (A1) and / or the second copolymer obtained by further neutralizing the copolymer (A1) with an alkaline substance. A copolymer salt of (B1) and a naphthalene-based cement dispersant,
A cement admixture having at least one cement dispersant selected from the group consisting of aminosulfonic acid-based cement dispersants, polycarboxylic acid-based cement dispersants, and lignin-based cement dispersants as a main component and having excellent slump retention.

(5) The weight ratio of the copolymer (salt) (A1 and / or B1) to the cement dispersant is 1:
The cement admixture according to (4) above, which is 99 to 99: 1.

(6) Any one of (1) to (5) above
A cement composition containing at least the cement admixture according to item 6, cement, and water.

(7) The cement according to the above (6), wherein the cement admixture is 0.01 to 1.0% by weight with respect to the cement, and the water / cement weight ratio is 0.15 to 0.7. Composition.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION First, the first cement admixture according to the present invention comprises a first copolymer (A) described below and / or the first copolymer (A) further treated with an alkaline substance. The main component is the first copolymer salt (B) obtained by the addition.

The first copolymer (A) has the general formula (1)
The first polyethylene glycol (meth) acrylate (a) represented by 5 to 90% by weight, preferably 5 to 70% by weight, more preferably 10 to 65% by weight, the second polyethylene represented by the general formula (2). Glycol (meth) acrylate (b) 5 to 90% by weight, preferably 1
0 to 90% by weight, more preferably 20 to 70% by weight,
Carboxylic acid-based monomer (c) represented by general formula (3) 5 to
90% by weight, preferably 5 to 40% by weight, more preferably 8 to 30% by weight, and 0 to 50% by weight, preferably 0 to 50% by weight of other monomer (d) copolymerizable with these monomers. It is derived at a ratio of 30% by weight (however, the total of (a), (b), (c) and (d) is 100% by weight). Further, the first copolymer salt (B) is
It is obtained by further neutralizing the first copolymer (A) with an alkaline substance.

General formula (1)

[0035]

Embedded image

In the formula (1), R1 represents a hydrogen atom or a methyl group, R2O represents an oxyethylene group, R3 represents a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, preferably 1 to 15 carbon atoms. , M is the average number of moles of oxyethylene groups added, and represents an integer of 1 to 97, preferably 1 to 10.

General formula (2)

[0038]

Embedded image

In the formula (2), R4 represents a hydrogen atom or a methyl group, R5 O represents an oxyethylene group, R6 represents a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, preferably 1 to 15 carbon atoms. , N is the average number of moles of oxyethylene groups added, and represents an integer of 4 to 100, preferably 11 to 100, and n ≠ m and n−m ≧
3, preferably nm ≧ 5.

General formula (3)

[0041]

[Chemical 21]

In the general formula (3), R7 is a hydrogen atom or a methyl group, M1 is a hydrogen atom, a monovalent metal atom,
Represents a divalent metal atom, an ammonium group or an organic amine group.

The second cement admixture according to the present invention is the second copolymer (A1) described below and / or the second copolymer (A1).
A second copolymer salt (B1) obtained by further neutralizing the copolymer (A1) of Example 1 with an alkaline substance, and
The main component is a mixture of the copolymer (A2) and / or the third copolymer salt (B2) obtained by further neutralizing the third copolymer (A2) with an alkaline substance. It is a thing.

The second copolymer (A1) is 5 to 65% by weight, preferably 5% by weight of the first polyethylene glycol (meth) acrylate (a) represented by the general formula (1).
To 60% by weight, 35 to 95% by weight, preferably 40 to 95% by weight of the carboxylic acid-based monomer (c) represented by the general formula (3), and other monomers which can be copolymerized with these monomers. Body (d) 0 to 50% by weight, preferably 0 to 30% by weight
(However, the total of (a), (c) and (d) is 100
% By weight. ) Is derived by the ratio. Also,
The second copolymer salt (B1) can be obtained by further neutralizing the second copolymer (A1) with an alkaline substance.

The third copolymer (A2) comprises the second polyethylene glycol (meth) acrylate (b) represented by the general formula (2) in an amount of 65 to 95% by weight, preferably 70 to 95% by weight. Carboxylic acid type monomer (c) represented by formula (3) 5 to 35% by weight, preferably 5 to 30% by weight and other monomer (d) 0 to be copolymerizable with these monomers. 50% by weight, preferably 0-30% by weight
(However, the total of (b), (c) and (d) is 100
% By weight. ) Is derived by the ratio. Also,
The third copolymer salt (B2) can be obtained by further neutralizing the third copolymer (A2) with an alkaline substance.

The second copolymer (A1) and / or the copolymer salt (B1) and the third copolymer (A2)
And / or the weight ratio with the copolymer salt (B2) is 1:
It is 99 to 99: 1, preferably 3:97 to 97: 3.

The third cement admixture according to the present invention is the second copolymer (A1) and / or the second copolymer (A1) obtained by further neutralizing the copolymer (A1) with an alkaline substance. Main components are a polymer salt (B1) and at least one cement dispersant selected from the group consisting of naphthalene-based cement dispersants, aminosulfonic acid-based cement dispersants, and polycarboxylic acid-based cement dispersants. Is.

The weight ratio of the second copolymer (A1) and / or copolymer salt (B1) to the cement dispersant is 1:99 to 99: 1, preferably 3:97 to 97 :.
3.

The polyethylene glycol (meth) acrylates (a) and (b) represented by the general formula (1) used in the present invention include short-chain polyethylene glycol (meth) acrylate and long-chain polyethylene glycol (meth) acrylate. There is.

Examples of the short-chain polyethylene glycol (meth) acrylate include hydroxyethyl (meth)
(Poly) oxyethylene glycol mono (meth) acrylic acid esters such as acrylate, polyethylene glycol mono (meth) acrylate, methoxy (poly) ethylene glycol mono (meth) acrylate, ethoxy (poly) ethylene glycol mono (meth) acrylate, etc. There is. It is important that the polyethylene glycol (meth) acrylate (a) has hydrophobicity in the short-chain polyethylene glycol of its side chain. Therefore, as polyethylene glycol (meth) acrylate (a),
An (alkoxy) (poly) ethylene glycol (meth) acrylate having an average added mole number m of 1 to 97, preferably 1 to 10 is preferable.

The long-chain polyethylene glycol-based monomer (b) used in the present invention is represented by the above-mentioned general formula, for example, polyethylene glycol mono (meth) acrylate, methoxy polyethylene glycol mono (meth) acrylate, ethoxy. Examples include polyoxyethylene glycol mono (meth) acrylic acid esters such as polyethylene glycol mono (meth) acrylate. In order to obtain a high water-reducing property, it is important to disperse the cement particles with steric repulsion and hydrophilicity due to the polyethylene glycol chain having an average addition mole number of 4 to 100 of polyethylene glycol (meth) acrylate (b). The average number of moles n of ethylene glycol chains added to the (alkoxy) polyethylene glycol (meth) acrylate (b) is 4
-100, preferably 11-100.

The carboxylic acid type monomer (c) is represented by the above general formula (3). Examples of the monomer (c) include acrylic acid, methacrylic acid, and monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts of these acids, and one or two of these may be mentioned. The above can be used.

The monomer (d) is a monomer copolymerizable with the monomers (a), (b) and (c). Monomer (d)
Examples of maleic acid, fumaric acid, citraconic acid,
Dicarboxylic acids such as mesaconic acid and itaconic acid and HO (R
8 O) p R9 (However, R8 O has 2 carbon atoms.
To 4 kinds of oxyethylene groups, or a mixture of 2 or more kinds, and in the case of 2 kinds or more, they may be added in blocks or randomly, and p is the average addition of oxyethylene groups. It is the number of moles and represents an integer of 1 to 100, and R9 represents hydrogen or an alkyl group having 1 to 22 carbon atoms. ) Monoesters or diesters with alcohols represented by:
Unsaturated amides such as (meth) acrylalkylamide;
Vinyl esters such as vinyl acetate and vinyl propionate; unsaturated sulfonic acids such as vinyl sulfonic acid, (meth) allyl sulfonic acid, sulfoethyl (meth) acrylate, 2-methylpropane sulfonic acid (meth) acrylamide and styrene sulfonic acid, and Those monovalent metal salts,
Divalent metal salts, aluminum salts, organic amine salts; aromatic vinyls such as styrene and α-methylstyrene; phenyl group-containing alcohols such as aliphatic alcohols having 1 to 18 carbon atoms or benzyl alcohol, and (meth) acrylic acid And the like; and one or more of these can be used.

The first copolymer (A) comprises the monomer (a),
It is derived using (b), (c) and, if necessary, the monomer (d) in the above-mentioned specific ratio. That is, the mixing ratio of the monomers (a), (b) and (c) is such that the monomer (a) is 5 to 90% by weight, the monomer (b) is 5 to 90% by weight, and the monomer is (C) is in the range of 5 to 90% by weight, preferably 5 to 70% by weight of the monomer (a) and 10 to 9 of the monomer (b).
0% by weight, the monomer (c) is in the range of 5 to 40% by weight, more preferably the monomer (a) is 10 to 65% by weight, the monomer (b) is 20 to 70% by weight, The monomer (c) is in the range of 8 to 30% by weight, and the mixing ratio of the monomer (d) copolymerizable with these monomers is 50% by weight or less, preferably 30% by weight or less. is there. If the ratio is out of this range, the desired cement dispersant having excellent performance cannot be obtained.

To obtain the copolymer (A), the above-mentioned monomer components may be copolymerized using a polymerization initiator. The copolymerization can be performed by a method such as polymerization in a solvent or bulk polymerization.

Polymerization in a solvent can be carried out batchwise or continuously, and the solvent used in this case is water;
Lower alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol; aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, cyclohexane and n-hexane; ester compounds such as ethyl acetate;
Ketone compounds such as acetone and methyl ethyl ketone; and the like. Raw material monomer and resulting copolymer (A)
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, from the viewpoint of the solubility and the convenience of using the copolymer (A). In that case, among lower alcohols having 1 to 4 carbon atoms, methyl alcohol, ethyl alcohol, isopropyl alcohol and the like are particularly effective.

When carrying out the polymerization in an aqueous medium, a water-soluble polymerization initiator such as ammonium or alkali metal persulfate or hydrogen peroxide is used as the polymerization initiator.
At this time, an accelerator such as sodium bisulfite and Mohr's salt may be used in combination. In the polymerization using a lower alcohol, an aromatic hydrocarbon, an aliphatic hydrocarbon, an ester compound or a ketone compound as a solvent, peroxides such as benzoyl peroxide and lauroyl peroxide; hydroperoxides such as cumene hydroperoxide; azo An aromatic azo compound such as bisisobutyronitrile is used as a polymerization initiator. In this case, an accelerator such as an amine compound may be used in combination. Further, when a water-lower alcohol mixed solvent is used, it can be appropriately selected and used from the above various polymerization initiators or a combination of a polymerization initiator and an accelerator. The polymerization temperature is appropriately determined depending on the solvent and the polymerization initiator used, but is usually 0 to 1
It is carried out within the range of 20 ° C.

The bulk polymerization is carried out by using a peroxide such as benzoyl peroxide or lauroyl peroxide; a hydroperoxide such as cumene hydroperoxide; an aliphatic azo compound such as azobisisobutyronitrile, etc. It is carried out within a temperature range of 200 ° C.

A thiol chain transfer agent may be used in combination for controlling the molecular weight of the resulting copolymer (A). The thiol chain transfer agent used at this time is represented by the general formula HS-R10-Eg (wherein R10 represents an alkyl group having 1 to 2 carbon atoms, E is -OH, -C).
OOM2, -COOR11 or -SO3 M2 group is represented, M2 is hydrogen, monovalent metal, divalent metal, ammonium group or organic amine group, R11 is an alkyl group having 1 to 10 carbon atoms, and g is 1 Represents an integer of ~ 2. ), For example, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycolate, octyl 3-mercaptopropionic acid, and the like. 1 type (s) or 2 or more types can be used.

Copolymer (A) thus obtained
Is used as the main component of the cement dispersant as it is, but if necessary, the copolymer salt (B) obtained by further neutralizing with an alkaline substance may be used as the main component of the cement dispersant. Preferred examples of such alkaline substances include inorganic substances such as hydroxides, chlorides and carbon salts of monovalent and divalent metals; ammonia; organic amines and the like.

The second copolymer (A1) is derived by using the monomers (a) and (c) and, if necessary, the monomer (d) in the above specified ratio. That is, the mixing ratio of the monomers (a) and (c) is 5 to 6 for the monomer (a).
5% by weight, the range of 35 to 95% by weight of the monomer (c), preferably 5 to 60% by weight of the monomer (a) and 40 to 95% by weight of the monomer (c). The mixing ratio of the monomer (d) copolymerizable with these monomers is 50% by weight or less, preferably 30% by weight or less. If the ratio is out of this range, the desired cement dispersant having excellent performance cannot be obtained.

The third copolymer (A2) is derived by using the monomers (b), (c) and, if necessary, the monomer (d) in the above-mentioned specific ratio. That is, the mixing ratio of the monomers (b) and (c) was 65 to 9 for the monomer (b).
5% by weight, the range of 5 to 35% by weight of the monomer (c), preferably 70 to 95% by weight of the monomer (b) and 5 to 30% by weight of the monomer (c). The mixing ratio of the monomer (d) copolymerizable with these monomers is 50% by weight or less, preferably 30% by weight or less. If the ratio is out of this range, the desired cement dispersant having excellent performance cannot be obtained.

The second and third copolymers (A1)
And (A2) and the second and third copolymer salts (B1) and (B2) are also the first copolymer (A).
And the same procedure as the first copolymer salt (B).

The weight average molecular weight of the copolymer (A), (A1), (A2) and / or the copolymer salt (B), (B1), (B2) used as the cement admixture of the present invention. Is preferably in the range of 500 to 500,000, particularly 5,000 to 300,000. When the weight average molecular weight is less than 500, the water-reducing performance of the cement dispersant deteriorates, which is not preferable. 5
If the molecular weight exceeds 0,000, the water-reducing performance of the cement dispersant and the ability to prevent slump loss decrease, which is not preferable.

The first copolymer (A) and / or the copolymer salt (B) can be used as a cement dispersant, either alone or as a mixture thereof.
Further, the copolymer (A) and / or the copolymer salt (B)
When used in combination with other known cement admixtures containing as a main component, such known cement admixtures include, for example, conventional cement dispersants, air entraining agents, cement wetting agents, expanding agents, waterproofing agents, Examples thereof include a retarder, a quick-setting agent, a water-soluble polymer substance, a thickener, a coagulant, a drying shrinkage reducing agent, a strength enhancer, a curing accelerator and an antifoaming agent.

Further, the second copolymer (A1) and /
Alternatively, the copolymer salt (B1) is the third copolymer (A2
) And / or copolymer salt (B2).

Further, the second copolymer (A1) and / or the copolymer salt (B1) is a naphthalene type cement dispersant, an aminosulfonic acid type cement dispersant, a polycarboxylic acid type cement dispersant, or a lignin type. It can also be used in combination with a known cement dispersant such as a cement dispersant.

The cement admixture of the present invention can be used in hydraulic cements such as Portland cement, belite-rich cement, alumina cement, various mixed cements, and hydraulic materials other than cements such as gypsum.

The cement admixture used in the present invention exhibits an excellent effect even when added in a small amount as compared with the conventional cement admixture. For example, when it is used for mortar or concrete using hydraulic cement, it is 0.01 to 1.0%, preferably 0.02 to 0.
An amount of 5% may be added during kneading.
By this addition, various desirable effects such as achievement of high water reduction rate, improvement of slump loss prevention performance, reduction of unit water amount, increase of strength, improvement of durability are brought about. If the addition amount is less than 0.01%, the performance is insufficient, and conversely 1.0
Even if a large amount exceeding 10% is used, the effect is practically leveled off and it is disadvantageous from the economical aspect.

In the cement composition of the present invention, the amount of cement used per 1 m 3 of the cement composition and the unit water amount are not particularly limited, but the unit water amount is 120 to 185 kg /
m3, water / cement weight ratio = 0.15-0.7, preferably unit water amount 120-175 kg / m3, water / cement weight ratio = 0.2-0.5% are recommended.

Generally, when comparing the hydration rates of the respective cement components, C3A is the fastest, and the hydration rate within a few minutes after water injection exceeds 30%. The reduction of the kneading water split by such rapid hydration may be one of the causes of slump loss. In addition, since the known cement dispersant adsorbs C3 A having the highest activity among the cement components, most of the added dispersant is buried in the crystals generated by the hydration reaction of C3 A. However, it is assumed that the loss of cement dispersive power over time may also be a factor of slump loss. Therefore, if the activity of C3A can be suppressed, it is expected that the slump loss can be greatly reduced. The copolymer of the present invention is, for example, a polycarboxylic acid type copolymer having both a short polyethylene glycol and a long polyethylene glycol in a side chain in one molecule, and the short polyethylene glycol side chain has a hydrophobic property. The activity of C3A is suppressed, and the long side chain of polyethylene glycol exerts a strong water reducing effect due to its hydrophilicity and steric repulsion.

However, the cement admixture of the present invention is not limited by these reasons.

The present invention will be described more specifically with reference to the following examples. In the examples,% is% by weight unless otherwise specified.
And parts are parts by weight.

Example 1 Production of Cement Admixture (1) 500 parts of water was charged into a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen introducing tube and a reflux condenser, and the inside of the reaction vessel was stirred. Replaced with nitrogen, and under a nitrogen atmosphere at 80 ℃
Heated up. Next, 300 parts of methoxy polyethylene glycol monomethacrylate (average number of moles of ethylene oxide added: 4), 200 parts of methacrylic acid, and 150 parts of water.
Part, and an aqueous monomer solution in which 13.5 parts of 3-mercaptopropionic acid as a chain transfer agent are mixed, and 10%
40 parts of ammonium persulfate aqueous solution was added dropwise over 4 hours, and after completion of the addition, 10% ammonium persulfate aqueous solution was added.
Parts were added dropwise over 1 hour. After that, 80 for one hour
The temperature was maintained at ℃, the polymerization reaction was completed, and the cement admixture (1) of the present invention consisting of an aqueous copolymer solution having a weight average molecular weight of 12300 was obtained.

Examples 2 to 3 Production of Cement Admixtures (2) and (3) The same operations as in Example 1 were performed to produce the cement admixtures (2) and (3) of the present invention. The contents are summarized in Table 1.

Example 4 Production of Cement Admixture (4) 500 parts of water was charged into a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen introducing tube and a reflux condenser, and the inside of the reaction vessel was stirred. Replaced with nitrogen, and under a nitrogen atmosphere at 80 ℃
Heated up. Next, methoxypolyethylene glycol monomethacrylate (average number of moles of ethylene oxide added: 4) 400 parts, methacrylic acid 100 parts, water 150
Part, and 40 parts of a 10% ammonium persulfate aqueous solution and a monomer aqueous solution mixed with 5.7 parts of 3-mercaptopropionic acid as a chain transfer agent were added dropwise over 4 hours, and after completion of the dropping, 10 parts of a 10% ammonium persulfate aqueous solution was further added to 1 part. Dropped over time. After that, continue for 1 hour at 80 ℃
The temperature was maintained to complete the polymerization reaction to obtain a cement admixture (4) composed of a polymer aqueous solution having a weight average molecular weight of 28,700.

Example 5 Production of Cement Admixture (5) A cement admixture (5) was produced in the same manner as in Example 4 below. The contents are summarized in Table 1.

[0078]

[Table 1]

Examples 6 to 8 and Comparative Examples 1 and 2 Mortar test 1 Polymer aqueous solution of cement admixture (1) to (3) of the present invention and polycarboxylic acid type cement dispersant (Aqua Lock manufactured by Nippon Shokubai Co., Ltd.) When FC-600 and "PC agent 1" are used together (Examples 6 to 8) and when the polymer aqueous solution of cement admixtures (4) and (5) is used together with PC agent 1 (comparison). The changes with time of the mortar flow values were compared between Examples 1 and 2).

The materials used in the test and the composition of the mortar were as follows: Chichibu Onoda High Flow Cement 800 g, calcium sulfoaluminate type expansive material 80 g, Toyoura standard sand 40
0 g, 220 g of water containing various polymers.

The mortar is prepared by mechanical kneading with a mortar mixer, and the hollow cylinder having a diameter of 55 mm and a height of 55 mm is filled with the mortar. Next, after the cylinder was lifted vertically, the diameter of the mortar spread on the table was measured in two directions, and the average was used as the flow value. Thereafter, the entire amount of the mortar was allowed to stand in a closed container for a predetermined time, and the same operation as above was repeated to measure the change with time in the flow value. Table 2 shows the results.

[0082]

[Table 2]

From Table 2, the cement admixture (1) of the present invention
~ When using (3) and PC agent 1 in combination, compared with the flow value when using cement admixture (4) and (5) and PC agent 1, the flow after 30 minutes and 60 minutes It can be seen that the decrease in the value is extremely small, and the cement admixture of the present invention exhibits an excellent effect in reducing slump loss.

Examples 9 to 10 and Comparative Examples 3 to 4 Mortar test 2 Cement admixture (1) of the present invention and polycarboxylic acid type cement dispersant (methoxy polyethylene glycol monomethacrylate (average number of moles of ethylene oxide added: 25)
Copolymer) having a weight ratio of 83.4 / 16.4 to methacrylic acid, a weight average molecular weight of 22000, and hereinafter "PC agent 2".
(Example 9), the cement admixture (1) of the present invention and a naphthalenesulfonic acid formaldehyde condensate (Kao Mighty 150, hereinafter “NSF”).
Say. ) Is used together (Example 10) and PC agent 2 and NSF are used alone (Comparative Example 3).
~ 4) and the time-dependent change of the mortar flow value were compared.

The materials and mortar used in the test were Chichibu Onoda ordinary Portland cement 600 g, Toyoura standard sand 600 g, and water 210 g containing various polymers.

Mortar is prepared by mechanical kneading with a mortar mixer, and the mortar is packed in a hollow cylinder having a diameter of 55 mm and a height of 55 mm. Next, after the cylinder was lifted vertically, the diameter of the mortar spread on the table was measured in two directions, and the average was used as the flow value. Thereafter, the entire amount of the mortar was allowed to stand in a closed container for a predetermined time, and the same operation as above was repeated to measure the change with time in the flow value. The results are shown in Table 3.

[0087]

[Table 3]

From Table 3, the cement admixture (1) of the present invention
When used in combination with polycarboxylic acid type cement dispersant or NSF, it can be seen that the reduction of the flow value is much smaller than that of polycarboxylic acid type cement dispersant or NSF used alone. From this, it is understood that the cement admixture of the present invention has an excellent effect of reducing slump loss.

Example 11 Production of cement admixture (6) 500 parts of water was charged into a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen introducing tube and a reflux condenser, and the inside of the reaction vessel was stirred. Replaced with nitrogen, and under a nitrogen atmosphere at 80 ℃
Heated up. Next, 50 parts of methoxy polyethylene glycol monomethacrylate (average number of moles of ethylene oxide added 4), methoxy polyethylene glycol monomethacrylate (average number of moles of ethylene oxide added 2)
3 pieces) 350 parts, methacrylic acid 100 parts, water 150 parts,
And a monomer aqueous solution mixed with 2.8 parts of 3-mercaptopropionic acid as a chain transfer agent and 40 parts of a 10% ammonium persulfate aqueous solution were added dropwise over 4 hours, and after completion of the addition, 10 parts of a 10% ammonium persulfate aqueous solution was added over 1 hour. Dropped. Then, the temperature was maintained at 80 ° C. for 1 hour to complete the polymerization reaction, and the weight average molecular weight of 2
A cement admixture (6) of the present invention consisting of 2000 polymer aqueous solution was obtained.

Examples 12 to 17 Production of cement admixtures (7) to (12) The same procedure as in Example 11 was carried out to produce cement admixtures (7) to (12) of the present invention. The contents are summarized in Table 4.

Comparative Example 5 Production of Comparative Cement Admixture (1) 500 parts of water was charged into a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen introducing tube and a reflux condenser, and the inside of the reaction vessel was stirred. To 80 ° C under nitrogen atmosphere
Heated up. Next, 10 parts of methoxypolyethylene glycol monomethacrylate (average number of moles of ethylene oxide added 4), methoxypolyethylene glycol monomethacrylate (average number of moles of ethylene oxide added 2)
3) 390 parts, methacrylic acid 100 parts, water 150 parts,
And a monomer aqueous solution mixed with 2.6 parts of 3-mercaptopropionic acid as a chain transfer agent and 40 parts of 10% ammonium persulfate aqueous solution were added dropwise over 4 hours, and after completion of the addition, 10 parts of 10% ammonium persulfate aqueous solution was added over 1 hour. Dropped. Then, the temperature was maintained at 80 ° C. for 1 hour to complete the polymerization reaction, and the weight average molecular weight of 2
A comparative cement admixture (1) consisting of 3000 polymer aqueous solutions was obtained.

Comparative Examples 6 to 7 Preparation of Comparative Cement Admixtures (2) to (3) Comparative cement admixtures (2) to (3) were produced in the same manner as in Comparative Example 5 below. The contents are summarized in Table 4.

[0093]

[Table 4]

Examples 18 to 24 and Comparative Examples 8 to 10 Mortar test 3 Cement admixtures (6) to (12) of the present invention shown in Table 4
(Examples 18 to 24) and comparative cement admixtures (1) to (3) (Comparative Examples 8 to 10) were added for comparison, and changes with time of mortar flow values were measured.

The materials and mortar formulations used in the test were 800 g of Chichibu Onoda High Flow Cement, 400 g of Toyoura standard sand, and 200 g of water containing the inventive or comparative cement dispersant.

Mortar is prepared by mechanical kneading with a mortar mixer, and the mortar is packed in a hollow cylinder having a diameter of 55 mm and a height of 55 mm. Next, after the cylinder was lifted vertically, the diameter of the mortar spread on the table was measured in two directions, and the average was used as the flow value. Thereafter, the entire amount of the mortar was allowed to stand in a closed container for a predetermined time, and the same operation as above was repeated to measure the change with time in the flow value. Table 5 shows the results.

[0097]

[Table 5]

Examples 25 to 31 and Comparative Examples 11 to 12 Concrete Test Normal Portland cement (Chichibu Onoda Cement: specific gravity: 3.16) as cement, and Oigawa water system land sand (specific gravity 2.62, FM2. 71), crushed hard sandstone from Ome (specific gravity 2.64, MS 20 mm) was used as coarse aggregate.

As the cement dispersant, the cement admixtures (6) to (12) of the present invention (Examples 25 to 31) and the comparative cement admixtures (1) to (2) (Comparative Examples 11 to 1)
2) was used. The air content was adjusted using a commercially available antifoaming agent.

The mixing conditions of concrete are that the unit cement amount is 660 kg / m 3, the unit water amount is 165 kg / m 3, and the fine aggregate ratio is 40.3%.

Under the above conditions, concrete was produced,
Slump and air volume are all measured by Japanese Industrial Standards (JIS
A 1101, 1128). Table 6 shows the results.

[0102]

[Table 6]

From Table 5 and Table 6, the cement admixture-added mortar and concrete of the present invention were tested after 30 minutes.
Even after 60 minutes, the decrease in the flow value is significantly suppressed,
It can be seen that it has an excellent effect in reducing slump loss.

[0104]

As described above, the cement admixture according to the present invention is excellent in high water reduction rate and slump retention,
A cement composition containing the cement admixture exhibits a high flow value.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichiro Nagaru 10-12 Ukishimacho, Kawasaki-ku, Kawasaki-shi, Kanagawa Nihon Shatai Co., Ltd. Inside the catalyst

Claims (7)

[Claims] 1. A compound of the general formula (1) (In the formula, R1 is a hydrogen atom, a methyl group, or R
2 O represents an oxyethylene group, R 3 represents a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, and m
Is the average number of moles of oxyethylene groups added, and is from 1 to 97.
Represents an integer. ) A first polyethylene glycol (meth) acrylate (a) of 5 to 90% by weight, represented by the general formula (2): (In the formula, R4 is a hydrogen atom, a methyl group, or R
5 O represents an oxyethylene group, R 6 is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, and n is
Is the average number of moles of oxyethylene groups added, and is 4 to 10
It represents an integer of 0, and n ≠ m and n−m ≧ 3. ) A second polyethylene glycol (meth) acrylate (b) of 5 to 90% by weight, represented by the general formula (3): (In the formula, R7 is a hydrogen atom, a methyl group, M
1 represents a hydrogen atom, a monovalent metal atom, a divalent metal atom, an ammonium group or an organic amine group. ) 5 to 90% by weight of the carboxylic acid-based monomer (c), and 0 to 50 other monomers (d) copolymerizable with these monomers.
Weight% (however, (a), (b), (c) and (d)
Is 100% by weight. ) First derived by the ratio
Of the copolymer (A) and / or the first copolymer salt (B) obtained by further neutralizing the copolymer (A) with an alkaline substance and having excellent slump retention. Cement admixture. 2. A compound of the general formula (1) (In the formula, R1 is a hydrogen atom, a methyl group, or R
2 O represents an oxyethylene group, R 3 represents a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, and m
Is the average number of moles of oxyethylene groups added, and is from 1 to 97.
Represents an integer. ) A first polyethylene glycol (meth) acrylate (a) 5 to 65% by weight, represented by the general formula (3): (In the formula, R7 is a hydrogen atom, a methyl group, M
1 represents a hydrogen atom, a monovalent metal atom, a divalent metal atom, an ammonium group or an organic amine group. ) 35% to 95% by weight of the carboxylic acid-based monomer (c), and other monomers (d) 0 to 5 copolymerizable with these monomers.
The second copolymer (A1) and / or the copolymer (A1) and / or the copolymer ((a), (c), and (d)) are introduced at a ratio of 0% by weight (however, the total of (a), (c) and (d) is 100% by weight). The second copolymer salt (B1) obtained by further neutralizing A1) with an alkaline substance, and a general formula (2): (In the formula, R4 is a hydrogen atom, a methyl group, or R
5 O represents an oxyethylene group, R 6 is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, and n is
Is the average number of moles of oxyethylene groups added, and is 4 to 10
It represents an integer of 0, and n ≠ m and n−m ≧ 3. A second polyethylene glycol (meth) acrylate (b) of 65 to 95% by weight, represented by the general formula (3): (In the formula, R7 is a hydrogen atom, a methyl group, M
1 represents a hydrogen atom, a monovalent metal atom, a divalent metal atom, an ammonium group or an organic amine group. ) 5 to 35% by weight of the carboxylic acid-based monomer (c), and 0 to 50 other monomers (d) copolymerizable with these monomers.
The third copolymer (A2) and / or the copolymer (A2) derived in a proportion of% by weight (however, the sum of (b), (c) and (d) is 100% by weight). ) Is further neutralized with an alkaline substance to obtain a cement admixture having a mixture of the third copolymer salt (B2) as a main component and having excellent slump retention. 3. The weight ratio of the copolymer (salt) (A1 and / or B1) and the copolymer (salt) (A2 and / or B2) is 1:99 to 99: 1.
The cement admixture described in. 4. A compound of the general formula (1) (In the formula, R1 is a hydrogen atom, a methyl group, or R
2 O represents an oxyethylene group, R 3 represents a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, and m
Is the average number of moles of oxyethylene groups added, and is from 1 to 97.
Represents an integer. ) A first polyethylene glycol (meth) acrylate (a) of 5 to 65% by weight, represented by the general formula (3): (In the formula, R7 is a hydrogen atom, a methyl group, M
1 represents a hydrogen atom, a monovalent metal atom, a divalent metal atom, an ammonium group or an organic amine group. 35 to 95% by weight of a carboxylic acid-based monomer (c) represented by), and another monomer (d) copolymerizable with these monomers (provided that (a), (c) and ( The total of d) is 100% by weight
It is. Second copolymer (A1) derived in the ratio
And / or a second copolymer salt (B1) obtained by further neutralizing the copolymer (A1) with an alkaline substance.
), And a slump containing at least one cement dispersant selected from the group consisting of a naphthalene-based cement dispersant, an aminosulfonic acid-based cement dispersant, a polycarboxylic acid-based cement dispersant, and a lignin-based cement dispersant. A cement admixture with excellent retention. 5. The weight ratio of the copolymer (salt) (A1 and / or B1) to the cement dispersant is 1:99 to.
The cement admixture according to claim 4, which is 99: 1. 6. A cement composition containing at least the cement admixture according to claim 1, cement and water. 7. The cement composition according to claim 6, wherein the cement admixture is 0.01 to 1.0% by weight with respect to the cement, and the water / cement weight ratio is 0.15 to 0.7. .