JP2000063164A - Cement admixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve high water reducing properties and improve setting retarding properties by including a polyalkyleneimine compound and a polycarboxylic acid-based dispersing agent. SOLUTION: A homopolymer obtained by polymerizing ethyleneimine, propyleneimine, etc., and a polyalkyleneimine comprising a mixture prepared by mixing two or more kinds of the alkylenimines can be used as a polyalkyleneimine compound. Polyethyleneimine is especially preferred. In a cement admixture, a relationship of X/Y<0.5 holds between the weight-average molecular weight (X) of the polyalkyleneimine compound and the weight-average molecular weight (Y) of the polycarboxylic acid. The polycarboxylic acid is capable of providing <=7.0 mM/g content of carboxyl groups expressed in terms of the number of mM of the carboxyl groups based on 1 g of the polycarboxylic acid. The polyalkyleneimine preferably has a polyether chain obtained by carrying out the addition polymerization of ethylene oxide in an amount exceeding the equivalent amount based on active hydrogen-containing amino groups contained therein.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cement admixture. More specifically, the present invention relates to a cement admixture containing a polyalkyleneimine compound and a polycarboxylic acid-based dispersant, which can achieve a high water reduction property and which has an improved setting retardation characteristic of the polycarboxylic acid-based dispersant. .

[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 for cement admixtures that greatly affect the quality and performance of products.

Among the concrete admixtures, polycarboxylic acid type dispersants have excellent water-reducing performance, but have a problem that they have a large setting retarding property.

Further, Japanese Patent Laid-Open No. 56-120559 proposes to use polyethyleneimine, which is less prone to set retardation, as a dispersant for cement. However, even when polyethyleneimine is used as a cement dispersant, the dispersibility in cement is very poor and high water reducing property cannot be achieved.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cement admixture which can achieve high water reduction and improved setting retardation.

[0006]

As a result of intensive studies, the present inventors have found that a cement admixture containing a polyalkyleneimine compound and a polycarboxylic acid-based dispersant has excellent dispersibility, and The inventors have found that the setting retardation characteristic of carboxylic acid-based dispersants is improved, and have completed the present invention.

That is, the present invention is a polymer composition and a cement admixture shown in the following (1) to (6).

(1) Polyalkyleneimine compound (A)
And a polycarboxylic acid (B).

(2) Polyalkyleneimine compound (A)
And a cement admixture containing a polycarboxylic acid (B).

(3) Polyalkyleneimine compound (A)
Can be achieved by a cement admixture obtained by neutralizing a part or all of the carboxyl groups of the polycarboxylic acid (B).

(4) It is also achieved by the cement admixture according to the above (2) or (3), wherein the polyalkyleneimine compound (A) is polyethyleneimine or a neutralized product thereof.

(5) Polyalkyleneimine compound (A)
In any one of the above (2) to (4), a relationship of X / Y <0.5 is established between the weight average molecular weight (X) of (4) and the weight average molecular weight (Y) of the polycarboxylic acid (B). It is also achieved by the cement admixture described.

(6) The polycarboxylic acid in which the amount of the carboxyl groups of the polycarboxylic acid (B) is 7.0 mmol / g or less in terms of mmol of the carboxyl groups per 1 g of the polycarboxylic acid (B). It is also achieved by the cement admixture according to any one of (2) to (5).

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The polyalkyleneimine compound (A) used in the present invention includes (a) ethyleneimine, propyleneimine, 1,2-butyleneimine, 2,3-butyleneimine and 1,1-dimethylethylene. In addition to homopolymers of these alkyleneimines obtained by polymerizing imines and the like by a conventional method, they are obtained by mixing two or more kinds of the above alkyleneimines, for example, polyalkylene composed of a mixture of ethyleneimine and propyleneimine. Imines can be used. Of these, polyethyleneimine is preferably used.

(B) A polyalkyleneimine having a polyether chain obtained by addition-polymerizing an alkylene oxide to the active hydrogen-containing amino group contained in the polyalkyleneimine shown in (a) above can be used. Among these, a polyalkyleneimine having a polyether chain obtained by addition-polymerizing an alkylene oxide in which the equivalent amount of active hydrogen of the amino group is added is preferable. Furthermore, it is preferable to use polyethyleneimine among the polyalkyleneimines. Among the alkylene oxides, those obtained by addition-polymerizing ethylene oxide are particularly preferable.

(C) An α, β-unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid or fumaric acid in some or all of the nitrogen atoms contained in the polyalkyleneimine shown in (a) above; Carboxylic acid and carbon number 1
A mono- or diester of an alcohol having 20 to 20 carbon atoms;
Polyalkyleneimine having a carboxyl group or ester group to which a mono- or diester with an alkoxy (poly) alkylene glycol to which 1 to 300 mol of the alkylene oxide of 4 is added by Michael can be used. The α, β-unsaturated carbonyl compound may be used alone or in combination of two or more. Α, β to be added
-It is preferable to use acrylic acid, methacrylic acid, or maleic acid as the unsaturated carbonyl compound. Moreover, it is preferable to use polyethyleneimine as the polyalkyleneimine to be added.

The weight average molecular weight of the polyalkyleneimine compound (A) shown in (a) to (c) above is from 300 to 5
It is possible to use those having a capacity of 0,000, but preferably 500 to 100,000, and more preferably 600 to
It is 10,000.

As the polycarboxylic acid (B) used in the present invention, the polycarboxylic acid (B) 1 converted to the unneutralized acid form is used.
It is important to use a polycarboxylic acid (B) in which the number of millimoles of carboxyl group per g is 7.0 mmol / g or less, preferably 5.5 mmol / g or less, and more preferably 3.5 mmol / g. g or less. When the carboxyl group in the polycarboxylic acid (B) is a salt, the amount of the carboxyl group of the polycarboxylic acid (B) is converted to an acid type carboxyl group with a strong acid such as hydrochloric acid, The carboxyl group can be determined by neutralization titration with an alkali such as sodium hydroxide.

Examples of the polycarboxylic acid (B) include the following <1> to <6>.

<1> A polymer obtained by copolymerizing an alkoxy (poly) alkylene glycol (meth) acrylate-based monomer, a (meth) acrylic acid-based monomer, and a copolymerizable monomer, if necessary. Coalescence can be used.
As an example, general formula (1) general formula (1)

[0021]

[Chemical 1]

(R ¹ represents hydrogen or a methyl group, and R ² O
Represents an oxyalkylene group having 2 to 4 carbon atoms, R ³ represents an alkyl group having 1 to 22 carbon atoms, an alkylphenyl group,
Represents a phenyl group, n represents the average number of moles of the oxyalkylene group added, and represents a number of 1 to 300. ) Alkoxy (poly) alkylene glycol (meth)
Acrylate-based monomer and general formula (2) general formula (2)

[0023]

[Chemical 2]

(R ⁴ represents hydrogen or a methyl group, M ¹ represents hydrogen, a monovalent metal, a divalent metal, an ammonium group or an organic amine group), and a (meth) acrylic acid-based monomer and Examples thereof include polymers obtained by copolymerizing a copolymerizable monomer, if necessary.

<2> It is possible to use a polymer obtained by copolymerizing a monomer obtained by adding an alkylene oxide to an unsaturated alcohol, a maleic acid-based monomer and, if necessary, a copolymerizable monomer. it can. As an example, general formula (3) general formula (3)

[0026]

[Chemical 3]

(R ⁵ represents hydrogen or a methyl group, R ⁶ O represents an oxyalkylene group having 2 to 4 carbon atoms, R ⁷ represents hydrogen or an alkyl group having 1 to 22 carbon atoms, an alkylphenyl group or a phenyl group. , M represents a number from 1 to 300, and r represents an integer from 0 to 2) (poly).
Alkylene glycol ether-based monomer and general formula (4) general formula (4)

[0028]

[Chemical 4]

(M ² and M ³ are hydrogen, monovalent metal, divalent metal,
Represents an ammonium group or an organic amine group, and X represents -OM
Represents ³ . However, it includes ^one in which oxygen bonded to M ¹ and carbon bonded to X are bonded to form an acid anhydride group. And a polymer obtained by copolymerizing a maleic acid-based monomer represented by (4) and a copolymerizable monomer as required.

<3> The following general formula (5) is used as the repeating unit.

[0031]

[Chemical 5]

(In the formula, R ⁸ O represents one or a mixture of two or more oxyalkylene groups having 2 to 18 carbon atoms, and in the case of two or more, they may be added in a block form or in a random form. R ⁹ may have 1 to 30 carbon atoms.
Represents a hydrocarbon group, M ⁴ represents hydrogen, a monovalent metal, a divalent metal, ammonium, or an organic amine group, and k represents the average number of moles of the oxyalkylene group added, and represents 1 to 300. ) And the following general formula (6):

[0033]

[Chemical 6]

(In the formula, M ⁵ and M ⁶ each independently represent hydrogen, a monovalent metal, a divalent metal, ammonium or an organic amine group.) And the following general formula (II) 7) General formula (7)

[0035]

[Chemical 7]

(However, in the formula, R ¹⁰ represents a hydrocarbon group having 1 to 30 carbon atoms.) A copolymer containing a repeating unit (III) can be used.

As an example, there may be mentioned a polymer obtained by esterifying an alkoxypolyalkylene glycol in a copolymer of alkyl vinyl ether and maleic anhydride.

<4> A graft polymer obtained by graft-polymerizing an unsaturated carboxylic acid type monomer with (poly) alkylene glycol can be used.

<5> Further, polyacrylic acid or polymethacrylic acid can be used.

<6> Further, other known polycarboxylic acid type dispersants can be used.

The weight average molecular weight of the polycarboxylic acid (B) shown in the above <1> and <2> is 5,000 to 500,00.
0 can be used, but preferably 10,0
00-100,000, more preferably 15,000
~ 50,000. Weight average molecular weight range is 5,0
If it is out of the range of 00 to 500,000, high water reducing performance and slump retention performance cannot be obtained.

Polycarboxylic acid (B) shown in <3> above
Can have a weight average molecular weight of 5,000 to 500,000, preferably 10,000 to 3
0,000, more preferably 30,000 to 20
50,000, more preferably 50,000 to 150,
The range is 000. Weight average molecular weight range is 5,000
If it deviates from the range of 0 to 500,000, high water reducing performance and slump retention performance cannot be obtained. In addition, <3
The repeating unit (I) of the polycarboxylic acid (B) shown in
The average number of added moles k of the oxyalkylene group is 1 to 30
The number is 0, preferably 110 to 300, more preferably 120 to 250.

The mixing ratio (A / B) of the polyalkyleneimine compound (A) and the polycarboxylic acid (B) is from 1/99 to
It is preferably 99/1 (weight ratio).

The total amount of the polyalkyleneimine compound (A) and the polycarboxylic acid (B) used is 0.
It is from 01 to 10%. If the amount used is less than 0.01%, the performance is insufficient, and conversely, if the amount used exceeds 10%, the effect is substantially leveled off and it is disadvantageous in terms of economy.

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

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 / m 2.
³ , preferably 130-175 kg / m ³ , water / cement weight ratio = 0.2-0.7, preferably 0.3-0.6 is recommended. Aggregates such as sand and gravel are added to the cement composition, if necessary.

The cement admixture of the present invention can be used in combination with a known cement dispersant. Known cement dispersants to be used in combination include lignin sulfonate, naphthalene sulfonic acid formalin condensate, melamine sulfonic acid formalin condensate, polystyrene sulfonate, amino sulfonate, and the like known cements. A plurality of dispersants can be used in combination.

Further, the cement admixture of the present invention can be used in combination with other known cement additives as exemplified below.

Water-soluble polymer substances such as poly (meth) acrylic acid (sodium), polymer emulsions such as alkyl (meth) acrylate, retarders, accelerators, early-strengthening agents, antifoaming agents, waterproofing agents, anti-reflective agents. Rust agents, swelling agents, shrinkage reducing agents, wetting agents, thickening agents, coagulants, self-leveling agents, coloring agents, antifungal agents, etc. can be mentioned, and a plurality of these known cement additives can be used in combination. is there.

[0050]

EXAMPLES The present invention will be described in more detail with reference to the following examples. Unless otherwise specified,% is% by weight.
Shall be represented.

<Measurement Method> The weight average molecular weight was measured under the following conditions.

[0052]   Measurement model Waters Millenium system   Detector Waters 410RI Detector   Used column made of TOSOH               TSK-GEL G4000SWXL               TSK-GEL G3000SWXL               TSK-GEL G2000SWXL   Eluent used Acetonitrile 1765g               Water 3235g               Sodium acetate trihydrate 34g               Adjust to pH 6.0 with acetic acid   Flow rate 1.0 ml / min   Measurement temperature 25 ℃   Standard sample polyethylene glycol               Molecular weight 170,000, 85,000, 46,000, 26, 000                       Use 12,600,7,100 The mortar test was performed by the following method.

The mortar was prepared by mechanical kneading with a mortar mixer, the mortar was packed in a hollow cylinder having a diameter of 55 mm and a height of 55 mm, then the cylinder was lifted vertically, and the diameter of the mortar spread on the table was measured in two directions. Was measured, and this average value was used as the flow value.

The setting time was measured by the following method.

The mortar prepared above was measured using a Vicat needle device in accordance with JIS R5201.

<Production Example> Production Example of Polycarboxylic Acid (B-2) 3-Methyl-3-butene-in a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen introducing tube and a reflux condenser. 50 g of unsaturated alcohol obtained by adding 35 mol of ethylene oxide on average to 1-ol, 6.4 g of maleic acid,
24.2 g of water was charged and heated to 60 ° C. with stirring.
Then, 14.3 g of a 6% ammonium persulfate aqueous solution was added to 3
The mixture was added dropwise over a period of time, and then the polymerization reaction was completed by maintaining the temperature at 60 ° C. for 1 hour to obtain a polycarboxylic acid (B-2) having a weight average molecular weight of 33,400 and a carboxyl group mmol of 1.95 mmol / g. Obtained.

Production Example of Polycarboxylic Acid (B-3) In a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen introducing tube and a reflux condenser, 2 g of ethyl vinyl ether / maleic anhydride copolymer, dehydrated Tetrahydrofuran 20
g was charged and the ethyl vinyl ether and maleic anhydride copolymer were dissolved. Next, dehydrated tetrahydrofuran 20
0.034 g of sodium hydride was added to a solution prepared by dissolving 7.8 g of methoxy polyethylene glycol (average number of moles of ethylene oxide added: 150) in g to separately generate methoxy polyethylene glycol alkoxide, and this alkoxide solution was allowed to stand at room temperature. It was added dropwise to the reaction vessel. After the completion of dropping, the reaction temperature was maintained at 55 ° C. and the reaction was performed for 24 hours. After completion of the reaction, tetrahydrofuran was distilled off with an evaporator, water and 30% aqueous sodium hydroxide solution were added to adjust the pH to 7.0, and the weight average molecular weight was 63,0.
00, the polycarboxylic acid (B-3) having 2.27 mmol / g of the number of millimoles of the carboxyl group was obtained.

As a polyalkyleneimine compound (A) used in Examples and Comparative Examples, polyethyleneimine (SP-018: weight average molecular weight 1800) manufactured by Nippon Shokubai Co., Ltd. was used.

As the polycarboxylic acid (B), (B-1)
(B-3) were used. (B-1) is a polycarboxylic acid type dispersant manufactured by Nippon Shokubai Co., Ltd. (a copolymer of methoxypolyethylene glycol methacrylate and methacrylic acid, a weight average molecular weight: 22000, the number of millimoles of a carboxyl group:
1.85 mmol / g) was used.

The molecular weight ratio of the polyalkyleneimine compound (A) and the polycarboxylic acid (B-1) is X / Y = 1800.
/22000=0.082.

The molecular weight ratio of the polyalkyleneimine compound (A) and the polycarboxylic acid (B-2) is X / Y = 1800.
/33,400=0.054.

The molecular weight ratio of the polyalkyleneimine compound (A) and the polycarboxylic acid (B-3) is X / Y = 1800.
/63,000=0.029.

Mortars containing the cement admixtures (1) to (3) of the present invention and the comparative cement admixtures (1) to (4) were prepared, and the flow value and the setting time were measured.

The materials and mortar formulations used in the test were Chichibu Onoda Ordinary Portland Cement 600 g, Toyoura Standard Sand 600 g, and 210 g water containing the invention or comparative cement admixture.

The results are shown in Table 1.

[0066]

[Table 1]

From Table 1, the cement admixture of the present invention (1)
Compared with the comparative cement admixture (1) using only polycarboxylic acid (B-1), the starting time is 45 minutes faster and the closing time is 2 hours faster. It is understood that the delay property can be improved. In the cement admixture (2) of the present invention using another polycarboxylic acid type dispersant (B-2), the polycarboxylic acid (B
It can be seen that the starting time is 15 minutes faster and the closing time is 1 hour 30 minutes faster than the comparative cement admixture (3) using only -2). Similarly, the cement admixture (3) of the present invention using the polycarboxylic acid type dispersant (B-3)
Then, it can be seen that the starting time is 30 minutes faster and the ending time is 1 hour 45 minutes faster than the comparative cement admixture (4) using only the polycarboxylic acid (B-3).

Further, in the comparative cement admixture (2) using only polyethyleneimine, the cement dispersibility was not obtained even when the addition amount was 1 wt% (based on the weight of cement).

[0069]

As described above, the cement admixture of the present invention maintains the excellent water-reducing performance of the polycarboxylic acid-based dispersant, and significantly improves the setting retardation of the polycarboxylic-acid-based dispersant to cause hardening. The time can be shortened.

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Claims (6)

[Claims] 1. A polymer composition containing a polyalkyleneimine compound (A) and a polycarboxylic acid (B). 2. A cement admixture containing a polyalkyleneimine compound (A) and a polycarboxylic acid (B). 3. A cement admixture obtained by neutralizing a part or all of the carboxyl groups of a polycarboxylic acid (B) with a polyalkyleneimine compound (A). 4. The cement admixture according to claim 2, wherein the polyalkyleneimine compound (A) is polyethyleneimine or a neutralized product thereof. 5. A relationship of X / Y <0.5 is established between the weight average molecular weight (X) of the polyalkyleneimine compound (A) and the weight average molecular weight (Y) of the polycarboxylic acid (B). The cement admixture according to any one of 2 to 4. 6. A polycarboxylic acid (B) in which the amount of carboxyl groups of the polycarboxylic acid (B) is 7.0 mmol / g or less as the number of millimoles of the carboxyl group per 1 g of the polycarboxylic acid (B). The cement admixture according to any one of claims 2 to 5.