JPH0812401A - Cement-dispersing agent - Google Patents

Abstract

PURPOSE:To obtain a cement-dispersing agent for improving the flow properties and fluidity retention by using a cocondensate between an aromatic compound bearing oxyalkylene groups, an aromatic compound bearing carboxyl groups and formaldehyde as a component. CONSTITUTION:This cement-dispersing agent comprises a cocondensation product between (A) at least one selected from aromatic compounds into which 1-300 moles of a 2-3C oxyalkylene groups are introduced, (B) at least one selected from aromatic compounds bearing carboxyl groups and formaldehyde or a neutralized salt of the cocondensate as a needed component. The addition of this agent to a cement composition causes no slump loss for hours to solve the troubles in cement pumping. Moreover, this agent increases the fluidity of a cement composition to facilitate the operations of filling the mold frame with cement and its large water-reducing effect enables the application thereof to high-strength concrete, too.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a cement dispersant. More specifically, it relates to a cement dispersant for the purpose of improving the fluidity and fluidity retention of hydraulic compositions such as cement paste, mortar and concrete.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
As a cement dispersant used for the purpose of improving the fluidity of a hydraulic composition, a naphthalenesulfonic acid formaldehyde condensate salt (hereinafter referred to as a naphthalene type), a melaminesulfonic acid formaldehyde condensate salt (hereinafter referred to as a melamine type), Polycarboxylic acid salts (hereinafter referred to as polycarboxylic acid type) and the like are used. However, each of them has excellent characteristics, but it has problems.

For example, the polycarboxylic acid type is excellent in dispersibility, but has a problem that the setting delay of concrete is large, and the naphthalene type and melamine type are excellent in dispersibility and curing characteristics, but slump loss (fluidity with time). The current situation is that there is no one satisfying all the properties required as a cement dispersant, and there are some problems.

[0004]

As a result of intensive studies, the inventors of the present invention have clarified the characteristics of various kinds of surfactants (including dispersants) with respect to concrete, in order to improve the above-mentioned problems, and On the other hand, the structure of the dispersant is designed in consideration of the dispersion mechanism by the steric barrier and the adsorption property to cement, and the dispersion property and the slump retention which are not obtained with the existing dispersants are excellent, and the dispersion with a small curing delay is obtained. It came to complete the agent.

That is, the present invention relates to an aromatic compound having a carboxyl group and one or more kinds (A) selected from aromatic compounds having 1 to 300 mol of an oxyalkylene group having 2 to 3 carbon atoms. One or more selected from
The present invention relates to a cement dispersant containing a formaldehyde cocondensate with (B) or a neutralized salt thereof as an essential component.

The present invention further relates to an aromatic compound having a carboxyl group and one or more kinds (A) selected from aromatic compounds having 1 to 300 mol of an oxyalkylene group having 2 to 3 carbon atoms. One or more selected from
The present invention relates to a cement dispersant containing, as an essential component, a formaldehyde co-condensate with (B) and one or more selected from aromatic compounds having a sulfonic acid group (C).

The present invention has a structure having an alkylene oxide and a carboxyl group in an aromatic formaldehyde co-condensation system, and is characterized in that it has a larger adsorption property for cement particles than general aromatic dispersants. Further, by appropriately coordinating the carboxyl group and the sulfonic acid group, temporal dispersive expression becomes possible.

That is, a carboxyl group having a strong adsorptive power is effective for adsorption during initial dispersion, and a sulfonic acid group is adsorbed over time to maintain fluidity for temporal dispersion retention. Therefore, the time required for fluidity can be controlled by introducing a carboxyl group and a sulfonic acid group.

Further, by introducing an alkylene oxide group into an aromatic formaldehyde co-condensation system as in the present invention, the dispersibility due to the electric repulsive force of the aromatic system is added to the steric barrier repulsive force of the alkylene oxide group, resulting in a dispersion effect. Is extremely high.

The aromatic compound (A) having 1 to 300 moles of oxyalkylene group having 2 to 3 carbon atoms used in the present invention is a polyoxy group having 1 to 300 moles of oxyalkylene group having 2 to 3 carbon atoms. Alkylenealkylphenols or polyoxyalkylenealkylnaphthols are used. One example is an addition product of 1 to 300 mol of oxyalkylene group to phenol, cresol, nonylphenol, naphthalene, methylnaphthalene, butylnaphthalene, bisphenol and the like.

From the viewpoint of co-condensation, a benzene ring derivative, that is, a polyoxyalkylene alkylphenol is preferable, and an oxyalkylene group adduct of phenol is particularly preferable.

The oxyalkylene group having 2 to 3 carbon atoms means ethylene oxide and propylene oxide, which may be random or block and is not limited. Further, the terminal of the oxyalkylene group may be a hydroxyl group, an alkyl ether or an alkyl ester.

The alkylene oxide adduct having 2 to 3 carbon atoms of phenol may have an average number of moles of addition of 1 or more, and may contain a non-added one or a non-added one. Can be used in any case. However, if the oxyalkylene group
If it exceeds 300 moles, the dispersibility is lowered, which is not preferable.

As the aromatic compound (B) having a carboxyl group used in the present invention, naphthalene ring or benzene ring derivatives such as isophthalic acid, oxynaphthoic acid, benzoic acid, hydroxybenzoic acid and the isomers thereof are used. It

However, considering the co-condensation property, the compound represented by the following general formula (a) is preferable.

[0016]

Embedded image

That is, o-hydroxybenzoic acid, m-hydroxybenzoic acid and p-hydroxybenzoic acid are preferred.

The aromatic compound (C) having a sulfonic acid group used in the present invention is an alkylnaphthalenesulfonic acid, an alkylphenolsulfonic acid, an anilinesulfonic acid, an alkylbenzenesulfonic acid or the like. Examples thereof include sulfonic acid, butylnaphthalene sulfonic acid, phenol sulfonic acid, cresol sulfonic acid, aniline sulfonic acid, benzene sulfonic acid and toluene sulfonic acid. It is also possible to use these isomers and those which have already been condensed. For example, lignin sulfonic acid or naphthalene sulfonic acid formaldehyde condensate can be used.

However, considering the co-condensation property, a sulfonic acid compound consisting of a phenol derivative, that is, an alkylphenol sulfonic acid is preferable, and a phenol sulfonic acid is particularly preferable.

Further, it may be reacted with another co-condensable monomer within a range that does not impair the effects of the present invention. Examples thereof include alkylphenols such as phenol and cresol.

The co-condensate can be used as a cement dispersant as it is, but it is preferably used as a neutralizing salt from the viewpoint of storage and use. Examples of the neutralizing salt include monovalent metal salts, divalent metal salts, ammonium salts, amine salts and substituted amine salts.

1 to 30 oxyalkylene groups having 2 to 3 carbon atoms
Formaldehyde co-condensate of 1 or 2 or more (A) selected from 0 mol of an aromatic compound and 1 or 2 or more (B) selected from an aromatic compound having a carboxyl group. Alternatively, in the neutralized salt thereof, the reaction molar ratio of (A) and (B) is (A) / (B) = 1 to 99/99 to 1 is suitable for maintaining dispersion for up to about 30 minutes. , 10 to 50/50
The range of to 90 is particularly excellent in initial dispersion and dispersion retention after 30 minutes. Therefore, the target fluidity can be obtained with a small amount of addition.

1 to 30 oxyalkylene groups having 2 to 3 carbon atoms
It has one or more kinds (A) selected from aromatic compounds introduced with 0 mol and one or more kinds (B) selected from aromatic compounds having a carboxyl group and a sulfonic acid group. In the formaldehyde co-condensate with one or more kinds (C) selected from aromatic compounds or a neutralized salt thereof, the reaction molar ratio of (A), (B) and (C) is
The range of (A) / (B) / (C) = 1 to 98/1 to 98/1 to 98 is suitable for dispersion up to about 60 minutes, and 5 to 50/5 to 90/5.
The range of 90 is particularly excellent in dispersion retention for 60 minutes or longer.

The standard method for producing the cocondensate of the present invention is shown below, but the present invention is not limited thereto.

As a method for producing the co-condensate, for example, a predetermined amount of alkylene oxide adduct and an aromatic compound having a carboxyl group, or an aromatic compound having a carboxyl group and an aromatic compound having a sulfonic acid group are used in a reaction vessel. And a predetermined amount of formalin water is added dropwise over 1 to 4 hours under stirring at 70 to 90 ° C., and after dropping, the mixture is stirred under reflux for 3 to 30 hours, cooled, and neutralized.

In the co-condensation system, water is added to control the condensation viscosity and the condensation time. The reaction system is carried out under acidic conditions, and when it is already under acidic conditions due to the aromatic compound having a sulfonic acid group and the unreacted acid contained therein, the condensation is carried out in the acidic region as it is. If the reaction system does not cause acidity, sulfuric acid or the like is added in advance to adjust the pH to 2 or less and the reaction is performed.

Weight average molecular weight of the cocondensate of the present invention (gel permeation chromatography / calculation of condensation degree from molecular weight in terms of sodium polystyrene sulfonate)
Is preferably 3,000 to 100,000, more preferably 5,000 to 50,000. If the average molecular weight is less than 3,000 or more than 100,000, the dispersibility is poor.

The amount of the cement dispersant of the present invention added to concrete is preferably 0.05 to 3.0% by weight, more preferably 0.1 to 1.0% by weight based on the cement.

The cement dispersant of the present invention can be used in combination with other dispersants. The dispersant may be any that is generally used as a dispersant for concrete, but it includes naphthalene sulfonate formaldehyde condensate, melamine sulfonate formaldehyde condensate, polycarboxylic acid or its ester or its salt, and refinement. Lignin sulfonic acid or its salt, polystyrene sulfonate, cement dispersant having phenol skeleton (for example, formaldehyde co-condensate with other monomer capable of co-condensing phenol sulfonic acid), aniline sulfonic acid as the main component Cement dispersants (for example, formaldehyde co-condensates with other monomers capable of co-condensing with aniline sulfonic acid) and the like, which have hitherto been called high performance water reducing agents, are preferably used.

A suitable combination ratio is 5 to 95% by weight based on the cement dispersant of the present invention.

The cement dispersant of the present invention is suitable for civil engineering, construction,
It is used for a hydraulic composition of cement such as a secondary product and is not particularly limited.

The cement dispersant 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, water retention agent, thickener, waterproofing agent, defoaming agent, water-soluble polymer, surfactant Various agents, cement paste mortar, various cements that make up concrete,
The thing added to hydraulic compositions, such as a blast furnace slag, a fly ash, and a silica fume, is mentioned.

[0033]

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, unless otherwise specified,
It is "% by weight".

In addition, the molecular weight in the examples represents the weight average molecular weight (gel permeation chromatography / sodium polystyrene sulfonate conversion).

Aromatic compound (A) having 1 to 300 mol of an oxyalkylene group having 2 to 3 carbon atoms used in Examples,
The contents of the aromatic compound (B) having a carboxyl group and the aromatic compound (C) having a sulfonic acid group are shown below. still,
EO represents ethylene oxide, PO represents propylene oxide, and the numerical value represents the average number of added moles.

Aromatic Compound (A) A-1; Phenol EO 10 mol adduct A-2; Phenol EO 25 mol adduct A-3; Phenol EO 75 mol adduct A-4; Phenol EO 120 mol adduct A -5; Phenol EO 250 mol / PO 20 mol block adduct A-6; Naphthol EO 2 mol adduct A-7 (comparative); Phenol EO 370 mol adduct.

Aromatic compounds (B) B-1; p-hydroxybenzoic acid B-2; o-hydroxybenzoic acid B-3; oxynaphthoic acid.

Aromatic compound (C) C-1; phenolsulfonic acid C-2; p-cresolsulfonic acid C-3; naphthalenesulfonic acid formaldehyde condensate
(Molecular weight 4500).

Production Example 1 (symbol D-1 of dispersant) 0.3 mol of A-1, 0.7 mol of B-1, 0.5 mol of sulfuric acid and 4 mol of water were charged in a reaction vessel with stirring, and 0.9 mol of 37% formaldehyde was added. Is added dropwise at 80 ° C. over 3 hours. After the dropping, raise the temperature to 105 ℃ and react for 10 hours, then cool to 50%.
Adjust to pH 8 with sodium hydroxide and let stand. After standing still,
The upper layer separated from the two layers was taken, and water was added to adjust the solid content to 30% to obtain a cocondensate having a molecular weight of 21,000.

Production Example 2 (symbol D-2 of dispersant) 0.2 mol of A-3, 0.7 mol of B-1, 0.1 mol of B-2, 0.5 mol of sulfuric acid and 5 mol of water were placed in a reaction vessel with stirring. After charging, 0.9 mol of 37% formaldehyde is added dropwise at 80 ° C. over 3 hours. After completion of the dropping, the temperature is raised to 105 ° C. and reacted for 12 hours, then cooled, adjusted to pH 8 with 50% sodium hydroxide and allowed to stand. After standing still, the upper layer separated into two layers was taken, and water was added to adjust the solid content to 30% to obtain a cocondensate having a molecular weight of 19,000.

Production Example 3 (Dispersant symbol D-3) In a reaction vessel with stirring, 0.1 mol of A-4, 0.9 mol of B-1, 0.5 mol of sulfuric acid and 4 mol of water were charged, and 0.9 mol of 37% formaldehyde was added. Is added dropwise at 80 ° C. over 3 hours. After the dropping, raise the temperature to 105 ℃ and react for 10 hours, then cool to 50%.
Adjust to pH 8 with sodium hydroxide and let stand. After standing still,
The upper layer separated from the two layers was taken and water was added to adjust the solid content to 30% to obtain a cocondensate having a molecular weight of 42,000.

Production Example 4 (Dispersant symbol D-4) 0.3 mol of A-1, 0.6 mol of B-1, 0.1 mol of C-1, 0.3 mol of sulfuric acid and 4 mol of water were placed in a reaction vessel with stirring. After charging, 0.9 mol of 37% formaldehyde is added dropwise at 80 ° C. over 3 hours. After the completion of the dropping, the temperature is raised to 105 ° C. and the reaction is performed for 10 hours. Then, the mixture is cooled, adjusted to pH 8 with 50% sodium hydroxide and left to stand. After standing still, the upper layer separated into two layers was taken and water was added to adjust the solid content to 30% to obtain a cocondensate having a molecular weight of 12,000.

Production Example 5 (symbol D-5 of dispersant) 0.3 mol of A-2, 0.6 mol of B-1, 0.1 mol of C-2 and 5 mol of water were charged in a reaction vessel with stirring, and 37% formaldehyde was added. 0.9 mol is added dropwise at 80 ° C. in 3 hours. After the dropping is completed, the temperature is raised to 105 ° C and reacted for 12 hours.
The pH was adjusted to 8 with sodium hydroxide and water was added to adjust the solid content to 30% to obtain a cocondensate having a molecular weight of 17,000.

Production Example 6 (symbol D-6 of dispersant) 0.2 mol of A-3, 0.7 mol of B-1 and 0.1 mol of C-3 in a reaction vessel with stirring (mol number as naphthalene skeleton)
, 5 mol of water was added, and 0.9 mol of 37% formaldehyde was added.
Add dropwise at 80 ° C for 3 hours. After the dropping was completed, the temperature was raised to 105 ° C and the reaction was carried out for 8 hours.
The pH was adjusted to 8 and water was added to adjust the solid content to 20% to obtain a cocondensate having a molecular weight of 25,000.

Production Example 7 (Dispersant symbol D-7) In a reaction vessel with stirring, 0.2 mol of A-4, 0.5 mol of B-2, 0.3 mol of C-1 and 5 mol of water were charged, and 37% formaldehyde was added. 0.9 mol is added dropwise at 80 ° C. in 3 hours. After the dropping is completed, the temperature is raised to 105 ° C and reacted for 12 hours.
The pH was adjusted to 8 with sodium hydroxide and water was added to adjust the solid content to 20% to obtain a cocondensate having a molecular weight of 31,000.

Production Example 8 (Dispersant symbol D-8) A reaction vessel with stirring was charged with 0.1 mol of A-5, 0.5 mol of B-2, 0.4 mol of C-1 and 6 mol of water, and 37% formaldehyde was added. 0.9 mol is added dropwise at 80 ° C. in 3 hours. After the completion of dropping, the temperature was raised to 105 ° C and reacted for 15 hours, then cooled to 50
The pH was adjusted to 8 with sodium hydroxide and water was added to adjust the solid content to 20% to obtain a cocondensate having a molecular weight of 33,000.

Production Example 9 (Dispersant symbol D-9) In a reaction vessel with stirring, 0.3 mol of A-6, 0.3 mol of B-2, 0.4 mol of C-1 and 6 mol of water were charged, and 37% formaldehyde was added. 0.9 mol is added dropwise at 80 ° C. in 3 hours. After the completion of dropping, the temperature was raised to 105 ° C and reacted for 25 hours, then cooled to 50
The pH was adjusted to 8 with sodium hydroxide and water was added to adjust the solid content to 20% to obtain a cocondensate having a molecular weight of 11,000.

Production Example 10 (Symbol D-10 of Dispersant) 0.1 mol of A-4, 0.6 mol of B-2, 0.3 mol of C-1 and 6 mol of water were charged in a reaction vessel with stirring, and 37% formaldehyde was added. 0.9 mol is added dropwise at 80 ° C. in 3 hours. After the completion of dropping, the temperature was raised to 105 ° C and reacted for 18 hours, then cooled to 50
The pH was adjusted to 8 with sodium hydroxide and water was added to adjust the solid content to 20% to obtain a cocondensate having a molecular weight of 26,000.

Production Example 11 (symbol D-11 of dispersant) 0.1 mol of A-3, 0.1 mol of B-3, 0.6 mol of C-1 and 3 mol of water were charged in a reaction vessel with stirring, and 37% formaldehyde was added. 0.9 mol is added dropwise at 80 ° C. in 3 hours. After the completion of dropping, the temperature was raised to 105 ° C and reacted for 25 hours, then cooled to 50
The pH was adjusted to 8 with sodium hydroxide and water was added to adjust the solid content to 30% to obtain a cocondensate having a molecular weight of 11,000.

Production Example 12 (symbol D-12 of dispersant) 0.1 mol of A-7, 0.5 mol of B-2, 0.4 mol of C-1 and 7 mol of water were charged into a reaction vessel with stirring, and 37% formaldehyde was added. 0.9 mol is added dropwise at 80 ° C. in 3 hours. After the completion of dropping, the temperature was raised to 105 ° C and reacted for 15 hours, then cooled to 50
The pH was adjusted to 8 with sodium hydroxide and water was added to adjust the solid content to 20% to obtain a cocondensate having a molecular weight of 41,000.

Content of the dispersant used in the comparative examples : Symbol NS; Naphthalene admixture (Mighty 150: manufactured by Kao Corporation) Symbol MS: Melamine admixture (Mighty 150V-2: manufactured by Kao Corporation) .

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

[0053]

[Table 1]

The concrete was produced by mixing the concrete materials shown in Table 1 and the cement dispersant with a tilting mixer at 25 rpm.
It was adjusted by kneading for 3 minutes. After measuring the slump value, it was further rotated at 4 rpm for 60 minutes, and the slump value after 60 minutes was measured. The amount of the dispersant added was such that the initial slump value was 20 ± 1 cm. The slump value was measured by the JIS A-1101 method. The measurement results are shown in Table 2.

[0055]

[Table 2]

Evaluation results As shown in Table 2, the cement dispersant of the present invention has a fluidity with a smaller addition amount as compared with the comparative product, and there is a difference between the slump value immediately after and after 30 minutes and 60 minutes. small. That is, it shows an excellent water reducing effect and a remarkable effect in preventing slump loss.

[0057]

When the cement dispersant according to the present invention is added to the cement composition, there is no slump loss for a long period of time, and therefore transportation troubles due to pumping are eliminated.
Furthermore, since the cement dispersant according to the present invention improves the fluidity of the cement composition, it facilitates the filling work into the mold, and the cement dispersant according to the present invention also has a large water-reducing effect, so that high-strength concrete is obtained. Application to is also expected.

Claims (12)

[Claims] 1. An oxyalkylene group having 1 to 3 carbon atoms 1
Formaldehyde co-condensation product of one or more kinds (A) selected from aromatic compounds introduced with 300 mol and one or more kinds (B) selected from aromatic compounds having a carboxyl group. Alternatively, a cement dispersant containing a neutralized salt thereof as an essential component. 2. An oxyalkylene group having 1 to 3 carbon atoms 1
It has one or more kinds (A) selected from aromatic compounds introduced with 300 mol and one or more kinds (B) selected from aromatic compounds having a carboxyl group and a sulfonic acid group. 1 or 2 selected from aromatic compounds
A cement dispersant containing a formaldehyde co-condensate with at least one species (C) or a neutralized salt thereof as an essential component. 3. The reaction molar ratio of (A) and (B) is (A) / (B) =
The cement dispersant according to claim 1, which is 1-99 / 99-1. 4. The reaction molar ratio of (A), (B) and (C) is (A) /
The cement dispersant according to claim 2, wherein (B) / (C) = 1 to 98/1 to 98/1 to 98. 5. An oxyalkylene group having 1 to 3 carbon atoms 1
The cement dispersant according to any one of claims 1 to 4, wherein the aromatic compound introduced with 300 mol is a benzene ring derivative. 6. The cement dispersant according to claim 5, wherein the benzene ring derivative is an oxyalkylene group addition product of phenol. 7. The aromatic compound having a carboxyl group is a naphthalene ring or benzene ring derivative.
The cement dispersant according to any one of 1. 8. The cement dispersant according to claim 7, wherein the benzene ring derivative is a compound represented by the following general formula (a). Embedded image 9. The cement dispersant according to claim 1, wherein the aromatic compound having a sulfonic acid group is a phenol derivative. 10. The cement dispersant according to claim 9, wherein the phenol derivative is phenolsulfonic acid. 11. The neutralization salt of the cocondensation product is a monovalent metal salt, 2
The cement dispersant according to any one of claims 1 to 10, which is a valent metal salt, an ammonium salt, an amine salt or a substituted amine salt. 12. The weight average molecular weight (gel permeation chromatography / sodium polystyrene sulfonate conversion) of the cocondensate is 3,000 to 100,000.
The cement dispersant according to any one of 1 to 11.