JPH0517189A - Cement admixture - Google Patents

Abstract

PURPOSE:To obtain a cement admixture capable of reducing slump loss caused in a hydraulic cement composition by using a formaldehyde adduct cocondensate of 3-5 components composed of specific compounds as a component. CONSTITUTION:A formaldehyde adduct cocondensate of 3-5 components compose. of compounds expressed by formulas I, II and/or III and IV and/or V is used as a component of a cement admixture. In the formula, R denotes H or lower alkyl; X denotes alkali metal; X1 denotes H, alkyl, carboxyl or its alkali metallic salt, sulfone group or its alkali metallic salt, OH or methoxy group; Y denotes carboxyl group or its alkali metallic salt, sulfone group or its alkali metallic salt; groups Z denote H or -CH2SO3X (X denotes alkali metal), provided that at least two of the groups Z denote H. The formaldehyde adduct cocondensate to be used has a three-dimensional molecular structure and it is presumed that the slump loss can be reduced thereby.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement admixture, and more particularly to a cement admixture such as a water reducing agent and a slump loss inhibitor used in cement compositions such as cement paste, mortar and concrete.

[0002]

2. Description of the Related Art Generally, a hydraulic cement composition gradually loses fluidity with the passage of mixing time (hereinafter, this phenomenon is referred to as slump loss), which causes a problem in workability in construction. That is, it is known that naphthalene-based and melamine-based admixtures that have been conventionally added as cement dispersants have a large slump loss.

As a countermeasure against this slump loss, a method of adding a curing retarder such as oxycarboxylic acid or lignin sulfonate has been proposed, but this method also delays the iron finishing time of the concrete and lowers the initial strength. In addition, the effect of preventing slump loss has not been sufficiently obtained, and a basic solution has not been reached.

[0004]

SUMMARY OF THE INVENTION The present invention is directed to a cement admixture, especially a concrete admixture, which improves the consistency of the cement composition and reduces slump loss. More specifically, when added to the cement composition, the fluidity of the cement composition is improved to increase the water reduction rate, and the cement composition can be transported for a long time without slump loss and pumped. An object is to provide a cement admixture that facilitates.

[0005]

[Means for solving the problems] Although the cause of slump loss is not clear, the admixture adsorbed on the cement particles (hereinafter referred to as a dispersant) is taken in by the chemical hydration reaction of the cement and dispersed. It is presumed that this is due to a decrease in the efficacy of.

[0006] Therefore, as a result of intensive studies, the present inventors have found that if the dispersant has a three-dimensional structure, the dispersant layer adsorbed on the cement particles becomes thicker and is incorporated into the cement hydrate. The inventors have found that the slump loss due to the retention of dispersibility is improved by delaying the heating time, and have completed the present invention.

That is, the present invention includes the following general formula (A) and general formula
(B) and / or general formula (C), and a co-condensate obtained by addition-cocondensing 3 to 5 components consisting of compounds represented by general formula (D) and / or general formula (E) with formaldehyde is essential. The present invention provides a cement admixture characterized by being a component.

[0008]

[Chemical 4]

[0009]

[Chemical 5]

It is presumed that the formaldehyde addition cocondensation products of the above 3 to 5 components used in the present invention have a three-dimensional molecular structure, which can reduce slump loss.

That is, 3 which constitutes the addition cocondensation product of the present invention.
The addition reactivity of formaldehyde to ~ 5 components may be 2 for methylol addition to phenol sulfonic acid, 4 for aniline derivative, 8 for aminonaphthalene derivative, 6 for melamine, and 4 for urea. . Therefore,
Copolycondensates of methylol adducts with respect to these 3 to 5 components are compared with conventional dispersants, such as naphthalene-based and melamine-based compounds and phenol-sulfanilic acid co-condensates disclosed in JP-A-1-113419. In view of the large number of added methylol, there is a possibility of easily forming a multidimensional structure. Therefore, 3 to 3 represented by the above general formula (A), (B) and / or (C) of the present invention, and (D) and / or (E)
The 5-component formaldehyde co-condensate exhibits excellent dispersibility and slump loss prevention effect when used as a cement admixture, as will be apparent from the examples described later.

The present invention is one in which the 3 to 5 components represented by the above general formulas (A), (B) and / or (C) and (D) and / or (E) are subjected to addition cocondensation with formaldehyde. And the expression
R in (A) means hydrogen or a lower alkyl group. As the lower alkyl group, carbon atom 1 such as methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, etc.
A straight or branched chain alkyl group having 1 to 6 is preferred.

The compound of the formula (B) is an aniline derivative containing a group selected from the group consisting of an alkyl group, a carboxyl group or an alkali metal salt thereof, a sulfone group or an alkali metal salt thereof, a hydroxyl group and a methoxy group.

The compound of the formula (C) is also an aminonaphthalene derivative containing a group selected from the group consisting of an alkyl group, a carboxyl group or an alkali metal salt thereof, a sulfone group or an alkali metal salt thereof, a hydroxyl group and a methoxy group. is there.

In the present invention, one or both of the compounds represented by the formulas (B) and (C) are used. Specific examples of the compounds of the formulas (B) and (C) used in the present invention include sulfanilic acid, methanilic acid, naphthoic acid, 1
-Naphthylamine-6-sulfonic acid (clave acid), 1
-Naphthylamine-5-sulfonic acid (laurent acid),
1-naphthylamine-3,6-disulfonic acid, 6-amino-4-hydroxy-2-naphthalenesulfonic acid or an alkali metal salt thereof is preferable, and examples of the alkali metal include sodium, potassium and lithium. Also,
In the present invention, sulfamic acid (NH ₂ SO ₃ ) or its alkali metal salt may be used in combination.

The compound of formula (D) is melamine or a sulfomethyl group-containing melamine. The compound of formula (E) is urea or a sulfomethyl group-containing urea. In the present invention, one or both of the compounds represented by formulas (D) and (E) are used.

Of the compounds represented by the general formulas (D) and (E),
The compound having a sulfomethyl group can be obtained by introducing the sulfomethyl group into the corresponding raw material, but the introduction of the sulfomethyl group may be carried out at the stage of the monomer or the resulting cocondensate. Further, when it is carried out at the monomer stage, it may be carried out for each monomer,
It may be performed on a mixture of raw material monomers including the monomers (A), (B) and (C). Of these, this method is preferable because the physical properties of the cocondensate formed can be easily controlled by introducing a sulfomethyl group into each monomer. But,
For simplification of the process, a sulfomethyl group may be introduced into the mixture of monomers (A) to (E).

The introduction of the sulfomethyl group can be carried out using a known sulfonating agent such as sodium sulfite, sodium hydrogen sulfite, sodium pyrosulfite, etc. However, sodium pyrosulfite is preferred from the viewpoint of small pH change in the system. The introduction of the sulfomethyl group may be complete or incomplete, but it is preferable to introduce the sulfomethyl group almost completely to the monomer from the viewpoint of controlling the physical properties of the copolymer.

When a sulfomethyl group is introduced into melamine, formaldehyde is first added and condensed to the amino group of melamine to introduce a methylol group, and then the hydroxyl group is replaced with the sulfone group derived from the sulfonating agent. Conceivable. In this case, there are 6 possible bonding sites, but at least 2 of them are considered to be used for forming the cocondensate according to the present invention, and therefore introduction of a sulfomethyl group can be carried out within 4 positions per 1 melamine monomer. However, the present invention does not exclude either case.

The formaldehyde used to form these 3 to 5 component formaldehyde addition cocondensates preferably uses formalin at a concentration of 30 to 40% by weight in its aqueous solution.

The addition cocondensation reaction of formaldehyde can be carried out in the range of pH 7 to 11 under basic conditions, but it is preferably carried out at pH 7.5 to 8.5. Furthermore, considering the efficiency of the methylol addition reaction and the condensation reaction, the methylolation is performed at pH 7.5 to pH 8.5, and then the condensation reaction is performed at pH 9.5 to 11, which is a two-step reaction by adjusting the pH. preferable.

The formaldehyde addition cocondensation product of the present invention comprises the above (A), (B) and / or (C), and (D) and / or
Alternatively, by containing 3 to 5 components of (E), a remarkable slump loss preventing effect is recognized as compared with the conventionally proposed cement dispersant. In particular, the constitutional molar ratio of the compounds represented by the general formulas (A), (B) and / or (C) and (D) and / or (E) is (A): [(B) + (C) ]: [(D) ＋ (E)
] = 0.1-1.0: 0.1-1.0: 0.1-1.0 shows excellent effect.

As an example of the cement admixture of the present invention, the compound of the above formula (A), the compound of the above formula (B), and the above formula
Examples thereof include addition cocondensates produced by using the three components of the compound (D) or (E). In this case, as the compound represented by the formula (B), the following formula (B ')

[0024]

[Chemical 6]

The compound represented by the formula (1) is used, melamine is used as the compound represented by the formula (D), and urea is used as the compound represented by the formula (E).

The number of moles of the addition-condensation reaction of formaldehyde of the present invention is determined by the following formulas (A), (B) and / or (C):
When the total number of moles of the compounds represented by (D) and / or (E) is 1, the range of about 1 to 5 moles is preferable.

The average molecular weight of the polycondensate of the addition co-condensate of the present invention is preferably in the range of 1,000 to 50,000, and preferably 2,000 to 10,000.
The degree is more preferable.

The method for producing the addition co-condensation reaction product is not particularly limited, and synthetic means usually used under basic conditions such as phenolsulfonic acid, aniline derivative, aminonaphthalene derivative, (sulfomethyl group-containing) melamine and / or
Or (sulfomethyl group-containing) drop reaction of formalin into urea, or after adding phenolsulfonic acid and / or aniline derivative with methylol in advance with formalin,
There is also a method of administering melamine (containing a sulfomethyl group) and / or urea (containing a sulfomethyl group) to carry out addition condensation, and any method is not limited in the scope of reaction under basic conditions.

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

An amount of aniline derivative such as sodium phenolsulfonate and sodium sulfanilate,
Melamine (containing a sulfomethyl group) and / or urea (containing a sulfomethyl group) and water were weighed to adjust the pH (7 to 8.5) and the solid content concentration, and then charged into a reaction vessel and added with formalin (at 80 to 90 ° C). 37% formaldehyde aqueous solution)
Add dropwise in 3 hours. After the dropping, the mixture is stirred under reflux for 3 to 30 hours. Then it is cooled to 30 ° C. and adjusted to pH 10-11. The cement admixture of the present invention can be obtained by further stirring and cooling under reflux for 3 to 10 hours.

The cement admixture of the present invention can also utilize an oxidation reaction, for example, the oxidation reaction shown in JP-A-60-11257 and JP-A-62-202850. There is no change in the dispersant that has many functional groups.

The cement admixture of the present invention is concrete,
Mortar, used as a dispersant for cement compositions such as cement paste, the addition method is preferably added at the same time as water injection for the purpose of preventing slump loss,
It is also possible to add it immediately after pouring water until the end of kneading, or to the cement mixture once kneaded. The cement admixture of the present invention can also be used as a high performance water reducing agent as a dispersant for secondary products.

When the cement admixture of the present invention is used, it may be used alone or in combination with a known cement admixture. In particular, even if the cement admixture has a large slump loss, the slump loss can be improved by using the cement admixture of the present invention together. The mixing ratio of the cement of the present invention and a known cement admixture can be arbitrarily selected according to the purpose, but if the mixing amount of the cement admixture of the present invention is 5% by weight or less, the slump loss improving effect is not expected so much.
Known cement admixtures that can be used in combination with the cement admixture of the present invention include naphthalene sulfonic acid formaldehyde condensate or a metal salt thereof, alkylnaphthalene sulfonic acid formaldehyde condensate or a metal salt thereof, melamine sulfonic acid formaldehyde condensate or a metal thereof. Examples thereof include salts, ligninsulfonic acid or a metal salt thereof, oxycarboxylic acid or a metal salt thereof, polycarboxylic acid or a metal salt thereof, and the like. Among them, it is preferable to use one or more selected from the group consisting of naphthalene sulfonic acid formaldehyde condensate or a metal salt thereof, melamine sulfonic acid formaldehyde condensate or a metal salt thereof, and lignin sulfonic acid or a metal salt thereof. When the cement admixture of the present invention and the above-mentioned conventionally known cement admixture are used in combination, they may be premixed and used, or may be added separately and used without any particular limitation.

Further, the cement admixture of the present invention is another known cement additive (material) such as a high performance water reducing agent, a fluidizing agent, an AE agent, an AE water reducing agent, a retarder, an early strengthening agent, and an accelerator. , Foaming agents, water retention agents, thickeners, waterproofing agents, rust preventives, coloring agents, antifungal agents, crack reducing agents, polymer emulsions, blast furnace slag, water-soluble polymers, expanding agents, fly ash, silica fume and A sustained release dispersant and a sustained release foaming agent can be used in combination.

[0035]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Production Example of Cocondensate (1) Sodium phenolsulfonate was placed in a reaction vessel equipped with a stirrer.
Charge 1.0 mol, 0.1 mol of sodium sulfanilate, and 1.0 mol of melamine, and add 0.1 N aqueous sodium hydroxide solution and water to adjust the pH of the solution to 8.5 and the solid concentration to 35% by weight. Next, prepare this solution at 85 ° C.
The temperature is raised to 0, formalin (3.3 mol as formaldehyde) is added with stirring, and the reaction mixture is stirred under reflux for 8 hours. Then, the mixture was cooled to 30 ° C., adjusted to pH 11 with a 40% aqueous sodium hydroxide solution, stirred under reflux for 12 hours, cooled, and then water was added to adjust the solid content concentration to 25% by weight. To obtain a cement admixture. Table 1 below shows the contents of the cocondensates Nos. 1 to 7 of the present invention produced according to Production Example (1). The number of moles of formalin in the table is the number of moles of formaldehyde (the same applies to the production examples below).

[0037]

[Table 1]

Production Example of Cocondensate (2) 1.0 mol of sodium metacresolsulfonate, 0.1 mol of sodium 6-amino-4-hydroxy-2-naphthalenesulfonate and 1.0 mol of melamine were placed in a reaction vessel equipped with a stirrer.
Charge the moles and add 0.1N aqueous sodium hydroxide solution and water to adjust the pH of the solution to 8.5 and the solid concentration to 35% by weight. Next, the adjusted solution is heated to 85 ° C and stirred with formalin (as formaldehyde).
2.5 mol) and the reaction mixture is stirred under reflux for 8 hours. After cooling, water is added to adjust the solid content concentration to 25% by weight to obtain the cement admixture of the present invention. Table 2 below shows the contents of the cocondensates Nos. 8 to 10 of the present invention produced according to Production Example (2).

[0039]

[Table 2]

Production Example of Cocondensate (3) Sodium phenolsulfonate was placed in a reaction vessel equipped with a stirrer.
Charge 1.0 mol, 0.5 mol of sodium sulfanilate and 1.0 mol of melamine, and add 0.1 N aqueous sodium hydroxide solution and water to adjust the pH of the solution to 8.5 and the solid concentration to 35% by weight. Next, prepare this solution at 85 ° C.
The temperature is raised to 0, formalin (2.5 mol as formaldehyde) is added with stirring, and the reaction mixture is stirred under reflux for 5 hours (first step). After that, it was cooled to 30 ° C., adjusted to pH 11 with 40% sodium hydroxide aqueous solution, stirred under reflux for 5 hours (second step), and after cooling, water was added to adjust the solid content concentration to 25% by weight. Adjust to obtain the cement admixture of the present invention. Cocondensates having various molecular weights can be obtained by changing the reaction time. Table 3 below shows the contents of the cocondensates Nos. 11 to 13 of the present invention produced according to Production Example (3).

[0041]

[Table 3]

Production Example of Cocondensate (4) Sodium phenolsulfonate was placed in a reaction vessel equipped with a stirrer.
Charge 1.0 mol, 0.1 mol of sodium sulfanilate, and 1.0 mol of melamine, and add 0.1 N aqueous sodium hydroxide solution and water to adjust the pH of the solution to 8.5 and the solid concentration to 35% by weight. Next, prepare this solution at 85 ° C.
The temperature is raised to 0, formalin (3.3 mol as formaldehyde) is added with stirring, and the reaction mixture is stirred under reflux for 8 hours. Then, it is cooled to 30 ° C., adjusted to pH 11 with 40% sodium hydroxide aqueous solution, and stirred under reflux for 12 hours. After stirring, 1.0 mol of sodium pyrosulfite is added, formalin (1.2 mol as formaldehyde) is added with stirring, and the reaction mixture is stirred under reflux for 2 hours. After cooling
Water is added to adjust the solid content concentration to 25% by weight to obtain the cement admixture of the present invention. Table 4 below shows the contents of the cocondensates Nos. 14 to 16 of the present invention produced according to Production Example (4).

[0043]

[Table 4]

Preparation Example of Co-condensate (5) 1.0 mol of melamine and 2.0 mol of formalin (2.0 mol of formaldehyde) were charged in a reaction vessel equipped with a stirrer, heated to 60 ° C. to completely dissolve melamine, and then sodium pyrosulfite was added. 1.0 mol, and further heated at 80 ° C. for 2 hours.
Next, 0.8 mol of sodium phenolsulfonate, 1.0 mol of sodium sulfanilate, and 0.1 N aqueous sodium hydroxide solution and water were added, and the prepared solution was heated to 95 ° C and stirred with formalin (1.8 mol of formaldehyde) while stirring. In addition, the reaction mixture is stirred under reflux for 8 hours. Then, the mixture is cooled to room temperature, adjusted to pH 11 with 40% aqueous sodium hydroxide solution, and stirred under reflux for 4 hours. After cooling to room temperature, the pH is adjusted to 9 with 20% sulfuric acid, and water is added so that the solid content concentration becomes 25% by weight to obtain a formalin cocondensate. Table 5 below shows the contents of the cocondensates Nos. 17 to 19 of the present invention produced according to Production Example (5).

[0045]

[Table 5]

Production Example (6) A cement admixture was prepared by using 70% by weight of the cocondensate No. 1 obtained in Production Example 1 and 30% by weight of a naphthalene-based dispersant (Mighty 150; manufactured by Kao Corporation). It was prepared (invention product 20). Further, 50% by weight of the cocondensate No. 1 obtained in Production Example 1 and 50% by weight of a melamine dispersant (Melment; Showa Denko KK) were used.
A cement admixture was prepared using the weight% (the present invention product 2
1).

<Evaluation as a Cement Admixture> The concrete composition was as follows. W / C = 55% S / A = 49% C = 320kg / m ³ where C is cement, W is water, S is fine aggregate and A
Indicates all aggregates. -The materials used are shown below. Cement = Central Portland Cement Fine aggregate = Coarse aggregate from Kinokawa = Crushed stone from Takarazuka ・ The mixer used was a tilting type and was kneaded for 3 minutes, then rotated 4 times per minute and stirred for 60 minutes. Table 6 shows the obtained evaluation results.

[0048]

[Table 6]

Note) * Addition amount:% solid content relative to cement. ** Comparative product A naphthalene dispersant (Mighty 150: Kao
(Made by Co., Ltd.). ** Comparative product B Melamine-based dispersant (Melment: Showa Denko
Manufactured by Co., Ltd.).

Evaluation results As shown in Table 6, the admixture of the present invention has a smaller difference between the slump value immediately after and 60 minutes later than the comparative example, and shows an excellent water reducing effect and a remarkable effect in preventing slump loss. .

[0051]

By using the formaldehyde addition co-condensate of the components 3 to 5 of the present invention as a cement admixture,
It is presumed that the multi-component structure of the admixture has a thickness in the admixture layer, the time for the admixture itself to be taken into the cement hydrate is delayed, and the slump loss is improved.

Claims (5)

[Claims] 1. The following general formula (A), general formula (B) and / or general formula (C), and general formula (D) and / or general formula (E)
A cement admixture, which comprises a cocondensate obtained by addition-cocondensing 3 to 5 components of the compound represented by the formula with formaldehyde as an essential component. [Chemical 1] [Chemical 2] 2. A compound represented by the following general formula (A), a compound represented by the general formula (B '), and a three-component formaldehyde addition cocondensate comprising melamine or urea as essential components. A cement admixture characterized by. [Chemical 3] 3. The constitutional molar ratio of the compounds represented by the general formula (A), the general formula (B) and / or the general formula (C), and the general formula (D) and / or the general formula (E) is A): [(B) + (C)]: [(D)
+ (E)] = 0.1-1.0: 0.1-1.0: 0.1-1.0 The cement admixture according to claim 1. 4. A method for producing concrete, which comprises using the cement admixture according to claim 1 in combination with another cement admixture. 5. The cement admixture used in combination is one selected from the group consisting of a naphthalene sulfonic acid formaldehyde condensate or a metal salt thereof, a melamine sulfonic acid formaldehyde condensate or a metal salt thereof, and lignin sulfonic acid or a metal salt thereof. Alternatively, the method for producing concrete according to claim 4, wherein there are two or more kinds.