JPH0725651A - Concrete admixture - Google Patents

Abstract

PURPOSE:To obtain an admixture showing excellent effects of fluidity, flow retaining properties and foam retention of a hydraulic composition such as concrete, etc., comprising a copolymer containing specific two kinds of (meth) acrylic acid-based monomers and an acrylic acid-based monomer or an unsaturated dicarboxylic acid monomer. CONSTITUTION:A concrete admixture comprises a copolymer obtained by copolymerizing a compound of formula I or formula II with a compound of formula III as an essential component. In the formula, R1 to R5 are H or methyl; R6 and R7 are group of formula TV, H or methyl; m1 to m3 are 0-2; n1 and n3 is 4-100; X1 and X2 are H or 1-3C alkyl; AO is 2-4C oxyalkylene group; SO is oxystyrene group; M1 and M2 are H, monovalent metal, ammonium group, amino group or substituted amino group. This concrete admixture takes balance of hydrophilic nature/hydrophobic nature of dispersant and surface mixing properties into account and styrene oxide is added to the root of ester or end of ethylene oxide and the copolymer is made hydrophobic and to strengthen foams and to stabilize foams.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a concrete admixture. More specifically, the present invention relates to a concrete admixture exhibiting excellent effects on fluidity, fluidity retention and air bubble retention of hydraulic compositions such as cement paste, mortar and concrete.

[0002]

BACKGROUND OF THE INVENTION Among concrete admixtures, naphthalene sulfonate formaldehyde condensate (hereinafter referred to as naphthalene type) and melamine sulfonate formaldehyde are typical examples of concrete admixture having a great fluidizing effect. There are substances called high performance water reducing agents such as condensates (hereinafter referred to as melamine-based) and polycarboxylic acid salts (hereinafter referred to as polycarboxylic acid-based).

While these admixtures each have excellent characteristics, they have problems. For example, naphthalene type and melamine type have excellent dispersibility and curing characteristics, but have problems in fluidity retention (called slump loss) and bubble volume retention, and polycarboxylic acid type has a problem that curing delay is large. ing.

In recent years, with the development of a polycarboxylic acid system exhibiting excellent fluidity, it becomes possible to obtain dispersibility with a low addition amount, and curing delay is being improved. For example, copolymers of a polyalkylene glycol monoester-based monomer having an unsaturated bond and an acrylic acid-based and / or unsaturated dicarboxylic acid-based monomer (Japanese Patent Publication No. 59-18338, Japanese Patent Publication No. 2-78978). No., Japanese Patent Publication No. 2-7898, Japanese Patent Publication No. 2-7901,
JP-B-2-11542, JP-A-3-75252, JP-A-59-
Water-soluble vinyl copolymers such as No. 162163).

However, the polycarboxylic acid system having these alkylene chains has a high entrainment property of bubbles, and the fluctuation due to the increase of the air amount during the period from concrete production to transportation is extremely large. 4 together
The current situation is that it is difficult to manage (about%). These problems are addressed by blending defoaming agents, etc.
The amount of air greatly varies depending on the mixing conditions, the agitator conditions of the mixer truck, and the transportation time, and the addition of the defoaming agent has not reached the basic solution, and improvement of the admixture itself is desired.

More specifically, it has been speculated that the excellent dispersion mechanism of a water-soluble vinyl copolymer having an oxyalkylene group is conventionally a dispersion mechanism in which the graft structure of the oxyalkylene chain serves as a steric barrier to prevent particle adhesion. As the oxyalkylene group, ethylene oxide, propylene oxide, butylene oxide and the like are mentioned in a known patent (the above-mentioned copolymer patent). However, in the case of ethylene oxide, the number of bubbles increases with time and the stability is poor as described above. Further, when propylene oxide and butylene oxide are used in combination, the defoaming property becomes remarkable, and it is extremely difficult to stabilize the bubbles constantly, and further, the dispersibility is lowered.

[0007]

Means for Solving the Problems As a result of intensive studies to improve the above-mentioned problems, the present inventors have found that the morphology of alkylene glycols of a polyalkylene glycol monoester monomer is foamability and bubble retention. It was found to affect sex. Specifically, in the polyalkylene glycol monoester-based monomer, than a copolymer of ethylene oxide adduct or a monomer of a block or random adduct of ethylene oxide and propylene oxide as a raw material,
It was found that by copolymerizing styrene oxide with acrylic acid or unsaturated dicarboxylic acids using an ester in which styrene oxide is added to the base of the ester or the end of alkylene glycol, this polymer exhibits extremely stable bubble retention. .

That is, the present invention comprises a copolymer obtained by polymerizing a compound represented by the following general formula (A) or (B) and a compound represented by the following general formula (C) as an essential component. And concrete admixtures.

[0009]

[Chemical 2]

(Wherein R _{1 to} R _{5 are} hydrogen or a methyl group R ₆ , R ₇ : (CH ₂ ) _{m 3} COOM ₂ , hydrogen or a methyl group m _{1 to} m ₃ are integers 0 to 2 n ₁ and n _4: 1 to 10 integer n _2, n _3: integer X ₁ of 4 to 100, X _2: hydrogen or an alkyl group having 1 to 3 carbon atoms AO: an oxyalkylene group having 2 to 4 carbon atoms SO: oxystyrene group (M ₁ and M _{2 are} hydrogen, monovalent metal, ammonium group, amino group or substituted amino group.) Generally, it is known that addition of propylene oxide causes defoaming property and defoaming property. . However, it is difficult to keep the amount of bubbles in the concrete constant as in the object of the present invention. The concrete admixture of the present invention was made in consideration of the hydrophilic / hydrophobic balance of the dispersant and the interfacial orientation. Therefore, styrene oxide is added to the ester root or the end of ethylene oxide to make it hydrophobic, thereby forming a foam film. Becomes stronger and the bubbles are stabilized.

In the present invention, the compound represented by the general formula (A) (hereinafter referred to as the monomer (A)) is styrene oxide (hereinafter referred to as SO) at the base of acrylic acid or methacrylic acid.
1 to 10 mol of ethylene oxide (
4 to 100 mol added, or EO / propylene oxide (hereinafter referred to as PO) / butylene oxide
(Hereinafter referred to as BO) in block or random form 4
~ 100 mol added. Also, 4 to 100 mol of EO is added to a lower alcohol having 1 to 3 carbon atoms, or EO is added.
After adding 4 to 100 moles of / PO / BO in a block or random manner and further esterifying the alcohol with acrylic acid or methacrylic acid with 1 to 10 moles of SO added, SO is added to the root A compound represented by the general formula (A) is obtained.

In the present invention, the compound represented by the general formula (B) (hereinafter referred to as monomer (B)) is a compound in which SO is added to the terminal of acrylic acid or methacrylic acid ester. After adding 4 to 100 moles of EO to methacrylic acid or adding 4 to 100 moles of EO / PO / BO in a block or random manner, SO is further added to 1 to 10 moles.
It is a product added with moles. Also, after adding 1 to 10 mol of SO to a lower alcohol having 1 to 3 carbon atoms, EO4 to 10
SO was added to the terminal of the ester by adding 0 mol or by esterifying the alcohol and acrylic acid or methacrylic acid to which 4 to 100 mol of EO / PO / BO were added in block or random form. A compound represented by the general formula (B) is obtained.

Of the compounds represented by the general formulas (A) and (B)
When the number of moles of SO added is 10 or more, the hydrophobicity becomes strong, the water solubility as an admixture is lowered, and the bubble retaining property is lowered, which is not preferable.

Further, when the number of moles of EO addition, the number of moles of EO / PO addition or the number of moles of EO / PO / BO addition is 4 or less, the dispersibility is decreased.
When it is 00 or more, the reactivity decreases, which is not preferable.

The compound represented by the general formula (C) (hereinafter referred to as the monomer (C)) used in the present invention includes an acrylic acid type monomer and an unsaturated dicarboxylic acid type monomer. Examples of acrylic acid-based monomers include acrylic acid, methacrylic acid, crotonic acid, and metal salts thereof. As the unsaturated dicarboxylic acid type monomer, maleic anhydride,
Examples thereof include maleic acid, itaconic anhydride, itaconic acid, citraconic anhydride, citraconic acid, fumaric acid, or metal salts, ammonium salts, amine salts or the like thereof.

The proportion (% by weight) of the monomers (A) or (B) and (C) in the copolymer of the present invention is (A) or (B).
The range of / (C) = 10 to 99/1 to 90 is suitable for bubble stability, and more preferably (A) or (B) / (C) = 40.
The range of ~ 99/1 to 60 is preferable.

The weight average molecular weight (gel permeation chromatography / polystyrene sulfonic acid conversion) of the copolymer of the present invention is preferably in the range of 1,000 to 500,000, and 5,000 to 20.
The range of 10,000 is more preferable. When the weight average molecular weight is 1000 or less, dispersibility is insufficient. Further, when it is 500,000 or more, cohesiveness becomes remarkable, which is not preferable.

The polymer of the present invention can be produced by a known method. For example, JP-A-59-162163, Japanese Patent Publication No. 2-11542, Japanese Patent Publication No. 2-7901, and Japanese Patent Publication No. 2-7897.
No. and the like.

Further, the addition amount of the concrete admixture of the present invention to concrete is 0.02-1.
0% by weight is preferable, and 0.05 to 0.5% by weight is more preferable.

The concrete admixture of the present invention can be used in combination with known additives (materials). For example, AE
Agent, AE water reducing agent, superplasticizer, high performance water reducing agent, retarder, early strengthening agent, accelerator, foaming agent, foaming agent, defoaming agent, thickener, waterproofing agent, antifoaming agent, silica sand, blast furnace Examples include slag, fly ash and silica fume.

Further, the concrete admixture of the present invention is added to cement paste, mortar, concrete or the like having a composition of hydraulic cement, and the content thereof is not limited.

[0022]

EXAMPLES The present invention will be specifically described below, but the present invention is not limited to these examples. In addition,% in the following examples is% by weight.

The number of moles of EO added or the number of moles of EO / PO random addition and the number of moles of SO added are indicated by the average number of moles added.

The contents and symbols of the monomer (A) used in the polymerization of the present invention are shown below. A-1 SO = 2 mol (base) / EO = 10 mol addition product to acrylic acid A-2 After EO addition, SO addition monoester of methanol and methacrylic acid (EO = 23, SO = 3) A-3 EO After addition, monoester of SO-added methanol and acrylic acid (EO = 50, SO = 5) A-4 EO / PO After random addition, monoester of SO-added methanol and methacrylic acid (EO = 85, PO = 4) , SO =
8) The contents and symbols of the monomer (B) used in the polymerization of the present invention are shown below. B-1 EO = 10 mol / SO = 2 mol (end) adduct to methacrylic acid B-2 SO After addition of EO, EO addition monoester of methanol and methacrylic acid (SO = 3, EO = 23) B-3 SO After addition, monoester of EO-added methanol and acrylic acid (SO = 1.5, EO = 45) B-4 After SO addition, EO / PO random addition, monoester of methanol and methacrylic acid (SO = 4, EO = 70) , PO ＝
5).

The contents and symbols of the EO or EO / PO addition ester monomer used as a comparative example are shown below. D-1 Monoester of EO-added methanol and methacrylic acid (EO = 23) D-2 EO / PO Random-added methanol and monoester of acrylic acid (EO = 23, PO = 3).

The production examples of the copolymer are shown below. Production Example 1 (Symbol A-1 in Example) 150 parts by weight of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 60 ° C in a nitrogen atmosphere. A-
50 parts of 1 and 50 parts of sodium methacrylate were charged, 30%
The pH was adjusted to 9 with an aqueous sodium hydroxide solution. After purging with nitrogen, 12 parts of 25% ammonium persulfate aqueous solution is added to start polymerization. After reacting for 7 hours and completing the polymerization, the mixture was completely neutralized with a 30% aqueous sodium hydroxide solution to obtain a copolymer having a molecular weight of 21,000.

Production Example 2 (Symbol A-2 in Example) 150 parts by weight of water was placed in a reaction vessel equipped with a stirrer, and the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 60 ° C. in a nitrogen atmosphere. A-
60 parts of 2 and 40 parts of sodium methacrylate are charged, 30%
The pH was adjusted to 9 with an aqueous sodium hydroxide solution. After purging with nitrogen, 13 parts of 25% ammonium persulfate aqueous solution is added to start polymerization. After reacting for 7 hours and completing the polymerization, the mixture was completely neutralized with a 30% aqueous sodium hydroxide solution to obtain a copolymer having a molecular weight of 15,000.

Production Example 3 (Symbol A-3 in Example) 130 parts by weight of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 60 ° C. in a nitrogen atmosphere. A-
70 parts of 3 and 30 parts of sodium acrylate were charged, and the pH was adjusted to 9 with a 30% aqueous sodium hydroxide solution. After nitrogen replacement,
Polymerization is started by adding 12 parts of 25% ammonium persulfate aqueous solution. After reaction for 7 hours and completion of polymerization, the mixture was completely neutralized with a 30% aqueous sodium hydroxide solution to obtain a copolymer having a molecular weight of 12,000.

Production Example 4 (Symbol A-4 in Example) 130 parts by weight of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 60 ° C. in a nitrogen atmosphere. A-
40 parts of 4 and 60 parts of sodium acrylate were charged, and the pH was adjusted to 9 with a 30% aqueous sodium hydroxide solution. After nitrogen replacement,
Polymerization is started by adding 10 parts of 25% ammonium persulfate aqueous solution. After reacting for 7 hours and completing the polymerization, the mixture was completely neutralized with a 30% aqueous sodium hydroxide solution to obtain a copolymer having a molecular weight of 21,000.

Production Example 5 (Symbol B-1 in the Example) 120 parts by weight of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 60 ° C. in a nitrogen atmosphere. B-
50 parts of 1 and 50 parts of sodium methacrylate were charged, 30%
The pH was adjusted to 9 with an aqueous sodium hydroxide solution. After purging with nitrogen, 10 parts of 25% ammonium persulfate aqueous solution is added to start polymerization. After reacting for 8 hours and completing the polymerization, the mixture was completely neutralized with a 30% aqueous sodium hydroxide solution to obtain a copolymer having a molecular weight of 22,000.

Production Example 6 (Symbol B-2 in the Example) 130 parts by weight of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 60 ° C. in a nitrogen atmosphere. B-
Charge 50 parts of 2 and 50 parts of sodium methacrylate, 30%
The pH was adjusted to 9 with an aqueous sodium hydroxide solution. After purging with nitrogen, 11 parts of a 25% ammonium persulfate aqueous solution is added to start polymerization. After reaction for 7 hours and completion of polymerization, the mixture was completely neutralized with a 30% aqueous sodium hydroxide solution to obtain a copolymer having a molecular weight of 24,000.

Production Example 7 (Symbol B-3 in the Example) 120 parts by weight of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 60 ° C. in a nitrogen atmosphere. B-
30 parts of 70 parts of 3 and 30 parts of sodium methacrylate were charged, and 30%
The pH was adjusted to 9 with an aqueous sodium hydroxide solution. After purging with nitrogen, 10 parts of 25% ammonium persulfate aqueous solution is added to start polymerization. After reacting for 8 hours and completing the polymerization, the mixture was completely neutralized with a 30% aqueous sodium hydroxide solution to obtain a copolymer having a molecular weight of 18,000.

Production Example 8 (Symbol B-4 in Example) 130 parts by weight of water was charged into a reaction vessel equipped with a stirrer, and the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 60 ° C. in a nitrogen atmosphere. B-
40 parts of 4 and 60 parts of sodium methacrylate were charged, 30%
The pH was adjusted to 9 with an aqueous sodium hydroxide solution. After purging with nitrogen, 11 parts of a 25% ammonium persulfate aqueous solution is added to start polymerization. After reacting for 7 hours and completing the polymerization, the mixture was completely neutralized with a 30% aqueous sodium hydroxide solution to obtain a copolymer having a molecular weight of 32,000.

Production Example 9 (symbol D-1 of the example (comparative example)
) 150 parts by weight of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 60 ° C in a nitrogen atmosphere. D-
50 parts of 1 and 50 parts of sodium methacrylate were charged, 30%
The pH was adjusted to 9 with an aqueous sodium hydroxide solution. After purging with nitrogen, 12 parts of 25% ammonium persulfate aqueous solution is added to start polymerization. After reacting for 7 hours and completing the polymerization, the mixture was completely neutralized with a 30% aqueous sodium hydroxide solution to obtain a copolymer having a molecular weight of 31,000.

Production Example 10 (Symbol D-2 of the Example (Comparative Example)
) 150 parts by weight of water was charged into a reaction vessel equipped with a stirrer, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 60 ° C in a nitrogen atmosphere.
Charge 50 parts of D-2 and 50 parts of sodium methacrylate,
The pH was adjusted to 9 with a 30% aqueous sodium hydroxide solution. After purging with nitrogen, 12 parts of 25% ammonium persulfate aqueous solution is added to start polymerization. After reacting for 7 hours and completing the polymerization, the mixture was completely neutralized with a 30% aqueous sodium hydroxide solution to obtain a copolymer having a molecular weight of 23,000.

The contents and symbols of the comparative admixtures used in the examples other than the comparative polymer of the copolymer are shown below. Reference symbol NS in the Examples: naphthalene-based admixture (Mighty 150
Manufactured by Kao Co., Ltd. Symbol MS in Examples: Melamine admixture (Mighty 150V-
2; manufactured by Kao Corporation).

Table 1 shows the mixing conditions of evaluation concrete as a concrete admixture .

[0038]

[Table 1]

The concrete was evaluated according to the concrete composition shown in Table 1 by mixing the material and admixture with a tilting mixer at 25 rpm.
× It kneaded for 3 minutes and adjusted. After measuring the air amount and the fluidity (slump value), it was further rotated at 4 rpm for 60 minutes, and after 60 minutes, the air amount and the slump value were measured. After adjusting the concrete, the amount of air was adjusted to 4 ± 0.5% with an air bubble entraining agent (Vinsol: manufactured by Yamasou Chemical Co., Ltd.). Slump value is JIS-
It was measured by the A 1101 method. Also, the initial slump value is 20 ±
The amount of the present invention and the comparative admixture was adjusted to 1 cm. The measurement results are shown in Table 2.

[0040]

[Table 2]

Evaluation Results As is clear from Table 2, the admixture of the present invention has a remarkable air bubble retention property as compared with the comparative product. Moreover, it has excellent fluidity,
The slump exhibits excellent effects with little change over time.

[0042]

When the concrete admixture according to the present invention is added to the concrete composition, the quality control of the concrete becomes easy because the change of the air amount and the fluidity is small over a long period of time.

Claims (3)

[Claims] 1. A concrete containing a copolymer obtained by polymerizing a compound represented by the following general formula (A) or (B) and a compound represented by the following general formula (C) as an essential component. Admixture. [Chemical 1] (In the formula, R _{1 to} R ₅ : hydrogen or a methyl group R ₆ , R ₇ : (CH ₂ ) _m3 COOM ₂ , hydrogen or a methyl group m _{1 to} m ₃ : integers 0 to 2 n ₁ , n ₄ : 1 To integers n ₂ and n ₃ : integers 4 to 100 X ₁ , X ₂ : hydrogen or an alkyl group having 1 to 3 carbon atoms AO: an oxyalkylene group having 2 to 4 carbon atoms SO: an oxystyrene group M ₁ , M ₂ : hydrogen, monovalent metal, ammonium group, amino group or substituted amino group.) 2. The composition ratio (% by weight) of the compound represented by formula (A) or (B) or (C) is (A) or (B) /
The concrete admixture according to claim 1, wherein (C) is in the range of 10 to 99/1 to 90. 3. The concrete admixture according to claim 1, wherein the average molecular weight of the copolymer is 1,000 to 500,000.