JPH05213643A - Cement admixture - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a cement dispersant capable of enhancing the strength of a concrete, mortar or paste which is a hydraulic mixture. [Structure] Consists of a compound (A) having a phenol skeleton and a polyol (B), and (A) / (B) is in a weight ratio of 80/20 to 99 /
1. A cement admixture characterized by being 1. [Effect] The product of the present invention in which the compound (A) having a phenol skeleton and the polyol (B) are used in combination has markedly improved initial strength and long-term strength as compared with the case where only the compound (A) is used. INDUSTRIAL APPLICABILITY According to the present invention, it is possible to remove concrete from a mold at an early stage, and it is also possible to increase long-term strength showing durability of concrete.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement compounding admixture, and more particularly to a cement dispersant capable of enhancing the strength of a hydraulic compound such as concrete, mortar or paste.

[0002]

2. Description of the Related Art Conventionally, a method of lowering the water / cement ratio has been generally used as a method of increasing the strength of a hardened concrete. But,
Since the workability deteriorates remarkably when the water / cement ratio becomes small, various dispersants have been used as a method for preventing this, but the use of the dispersant involves a decrease in initial strength. Further, a method of increasing the initial strength by mixing an early strengthening agent such as calcium chloride or a fiber, and a method such as strength accelerating curing are known. Rebar /
It has drawbacks such as corrosion of steel frame and complicated operation. Therefore, it has been desired to develop an agent that enhances the short-term / long-term strength without mixing early-strengthening agents, fibers, etc., or using special curing, and without adversely affecting the physical properties of concrete. ..

[0003]

The present invention has been made to improve the above-mentioned problems of the conventional method. By using a polyol together with a cement dispersant having a phenol skeleton, a hardened concrete is adversely affected. The present invention has been completed by discovering that the strength is enhanced without the need. That is, the present invention comprises a compound (A) having a phenol skeleton and a polyol (B), wherein (A) / (B)
Relates to a cement admixture characterized by a weight ratio of 80/20 to 99/1.

The mechanism of increasing the initial strength of the hardened concrete according to the present invention is presumed as follows. The cement particles in the cement mixture, which is made by mixing cement, water, and if necessary, sand, gravel, and an admixture (material), gradually develops strength after contact with water due to a hydration reaction. To do. At this time, if a dense cement hydrate is formed, the structure becomes dense and the strength is improved.

The present inventors have conducted extensive studies to efficiently densify cement hydrates, and as a result, by using a compound (A) having a phenol skeleton and a polyol (B) in combination,
The inventors have found that the structure of the hardened cement is dense and the strength is dramatically improved, and the present invention has been completed. This is because the hydroxyl groups in the polyol come out of the cement in the liquid phase.
It is presumed that Ca ²⁺ ions are trapped (trapped), supersaturated state is formed, and when crystal formation starts, fine nuclei are rapidly formed to form a hydrated crystal.

The details of the present invention will be described below. Compound (A) having a phenol skeleton in the present invention
Is selected from the group consisting of one or more phenols or their derivatives selected from the group of compounds represented by the following general formula (a), or a group consisting of this and melamine or its derivatives represented by the general formula (b) and urea. A condensate obtained by condensing or co-condensing one or more kinds of the above compounds with formaldehyde in the presence of an amino-based polymerization terminator is preferable.

General formula (a)

[0008]

[Chemical 6]

X ₃ is selected from the group consisting of hydrogen, a lower alkyl group having 1 to 3 carbon atoms, 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.

General formula (b)

[0011]

[Chemical 7]

Here, X ₄ is selected from hydrogen, a hydroxyl group and —CH ₂ SO ₃ M ₁ , and M ₁ means hydrogen or an alkali metal. X ₅ is selected from hydrogen, hydroxyl group and —CH ₂ SO ₃ M ₂ , and M ₂ means hydrogen or an alkali metal. X ₆ is selected from hydrogen, hydroxyl group and —CH ₂ SO ₃ M ₃ , and M ₃ means hydrogen or an alkali metal.

The amino-based polymerization terminator is characterized by having an amino group and a functional group selected from the group consisting of a sulfone group, a carboxyl group, a hydroxyl group and a methoxy group. In the production of compound (A) used in the present invention, pH 3-12
In the reaction medium, the electrophilic addition reaction of formaldehyde to an aromatic amine is more likely to occur to an amino group than to an aromatic ring. In this case, a compound having only an amino group will be an amino resin, but when it has a functional group such as a sulfone group, a carboxyl group, a hydroxyl group, or a methoxy group in the molecule, the electron density of the nitrogen atom of the amino group is lowered. Therefore, the addition reaction of formaldehyde can be suppressed at the stage of the monomethylolation reaction. In the production of the compound (A) used in the present invention, it is presumed that the polymerization-terminating action is exhibited due to the reaction selectivity of the above amino-type polymerization terminator.

The amino-based polymerization terminator includes at least one compound selected from the group of compounds represented by the following general formulas (c), (d), (e) and (f).

General formula (c)

[0016]

[Chemical 8]

Here, X ₁ is selected from the group consisting of hydrogen, a lower alkyl group having 1 to 3 carbon atoms, 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, and Y ₁ Is selected from the group consisting of carboxyl groups or alkali metal salts thereof and sulfone groups or alkali metal salts thereof.

General formula (d)

[0019]

[Chemical 9]

X ₂ is selected from the group consisting of hydrogen, a lower alkyl group having 1 to 3 carbon atoms, 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, and Y ₂ Is selected from the group consisting of carboxyl groups or alkali metal salts thereof and sulfone groups or alkali metal salts thereof.

General formula (e)

[0022]

[Chemical 10]

Here, Z is selected from hydrogen, an alkyl group having 1 to 3 carbon atoms, and —CH ₂ SO ₃ M ₅ , and M ₄ and M ₅ mean hydrogen or an alkali metal. Formula _{(f) H 2 NSO 3 M} 6 wherein M ₆ represents a hydrogen or an alkali metal. The water-soluble amino-based polymerization terminator preferably used in the present invention, 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 and sulfamic acid, N-methyl sulfonated urea, N, N-dimethyl sulfonated urea and the like compounds having a sulfone group or alkali metal salts thereof, and the alkali metal salts include Examples thereof include sodium, potassium and lithium.

In the production of the compound (A) used in the present invention, the polymerization rate is controlled and the weight average molecular weight is 1,0
Mw / Mn (weight average molecular weight /
An amino-based polymerization terminator is used as an agent for controlling the number average molecular weight) to be 5.0 or less. According to this method, a formaldehyde condensate or cocondensate having a molecular weight most suitable for its use, especially dispersion of various powders is used. Can be synthesized.

The optimum amount of formalin used in the synthesis of the formaldehyde condensate or cocondensate is 0.7 to 5 times, preferably 0.9 to 2.5 times the mol of the total amount of the formaldehyde condensed monomer. The reactivity of the amino-based polymerization terminator depends on the type and number of functional groups. Suitable types of functional groups include sulfonic acid groups, carboxyl groups, hydroxyl groups and methoxy groups,
Particularly, a sulfone group and a carboxyl group are preferable. With respect to the number of functional groups, the number of functional groups is usually 1 or more to exert a polymerization terminating action, but it is preferable to have 1 to 2 in the case of sulfone groups and 2 or more in the case of other functional groups.

The synthesis ratio (molar ratio) of the amino-based polymerization terminator and the monomer used in the present invention is 0.2: 1.0 to 5.0:
1.0 is good. Even if the amount of the polymerization terminator is out of this range, there is a polymerization termination effect, but in general, if the amount is 0.2 mol or less with respect to the monomer, a sufficient polymerization termination effect will not be expressed, which causes broadening of the molecular weight distribution and Mw / Mn Increase. If it is 5 mol or more, the condensation reaction is controlled and the degree of condensation is difficult to increase.
The one or more compounds selected from the group consisting of melamine or a derivative thereof represented by the general formula (b) and urea used in the present invention are selected from the group of compounds represented by the general formula (a). It is preferably used in an amount of 0 to 2 times the molar amount of one or more phenols or derivatives thereof.

The pH range for producing the condensate or cocondensate which is the compound (A) used in the present invention is pH 3-12.
However, a pH of 7-9 is particularly preferable. In addition, pH3
As the amino-based polymerization terminator used in the range of ~ 6, N, N
-Dimethylsulfonated urea and N-methylsulfonated urea are particularly good. When the pH is 3 or less, the condensation rate of the monomer is remarkably increased, so that the polymerization terminating action is difficult to be exhibited. On the other hand, when the pH is 12 or more, the condensation rate of the monomer is low, so that it takes a long time to condense to a predetermined molecular weight. The weight average molecular weight of the compound (A) used for production in the present invention is
If it is 1,000 to 50,000, it has sufficient dispersibility as a dispersant for a cement composition, but 3,000 to 20,000 is more desirable.

The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the component having a molecular weight of 1,000 or more in the compound (A) used in the production of the present invention is 5.0 or less, more preferably 3.0 or less is good. When Mw / Mn is 5.0 or more, the width of the molecular weight distribution becomes too wide, and the amount of active ingredient suitable for dispersion decreases. As a result, the dispersibility is reduced. The compound (A) is, for example, Japanese Patent Application No. 3-137045, Japanese Patent Application No. 3-169739, and Japanese Patent Application No.
The compounds described in 165642 and Japanese Patent Application No. 3-165640 are shown below.

The polyol (B) is a compound having two or more hydroxyl groups in the molecule, and examples thereof include monosaccharides such as gluconic acid and glucose, polysaccharides such as starch, cellulose, and sucrose. The amount of polyol (B) in the cement admixture of the present invention is 1 to 20 parts by weight. If it exceeds 20 parts by weight, delayed curing will be remarkable and sufficient initial strength cannot be obtained. On the other hand, if it is less than 1 part by weight, the amount of the polyol will be insufficient to serve as nuclei for hydrate-generated crystals, resulting in sufficient initial strength. You cannot expect the effect of promotion

The optimum amount of the cement admixture of the present invention to be added is about 0.05 to 4.0% by weight based on the cement. The cement admixture of the present invention is a usual cement dispersant, for example, a naphthalene-based water reducing agent such as β-naphthalenesulfonic acid formaldehyde high condensation product or a salt thereof, a melamine-based water reducing agent such as a water-soluble salt of a sulfonated melamine resin, Lignin-based water reducing agents such as ligninsulfonic acid or salts thereof, or anhydrides or water-soluble salts of copolymers of olefins having 2 to 8 carbon atoms and ethylenically unsaturated dicarboxylic acids, (meth) acrylic acid-based polymers , And a maleic acid-based polymer can be used in combination.

The method of adding the cement admixture according to the present invention to the cement mixture may be suspension, powder or granule. The timing of addition is dry blending with cement, dissolution in kneading water, It is also possible to add it to the cement composition once kneaded. Further, other cement additives (materials) such as an air entraining agent, a fluidizing agent, a waterproofing agent, a swelling agent (material), glass fiber, fly ash, blast furnace slag and the like can be used in combination. The concrete containing the cement admixture according to the present invention can be hardened by a method of hardening a normal concrete, and can be hardened also by a method such as steam curing or autoclave curing.

[0032]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Example 1 The compound (A) used here was prepared as follows. Phenol 1.0 mol, melamine 0.5 in a reaction vessel equipped with a stirrer
Mol and 0.8 mol of sulfanilic acid were added, and 0.1N sodium hydroxide aqueous solution and water were added to adjust the pH to 5 and the solid content concentration.
Adjust to 40% by weight. The temperature of this solution is raised to 70 ° C., 2.5 mol of 37% formalin is added, and the mixture is further stirred under reflux for 10 hours. This condensate was adjusted to pH 8. with 0.1N sodium hydroxide aqueous solution.
Adjusted to 5. The weight average molecular weight Mw by gel permeation chromatography was 10,000 and Mw / Mn (number average molecular weight) was 2.5. . Based on the formulation shown in Table 1, add 40 l of concrete material and specified cement admixture using a 60 l tilting mixer, knead at high speed for 2 minutes, and then at a constant speed agitating (rotating mixing) at 4 rpm. A concrete test was conducted by measuring the slump in time.

[0033]

[Table 1]

Materials used Cement (C): ordinary Portland cement (specific gravity 3.1
7) Fine aggregate (S): Kinokawa (specific gravity 2.57) Coarse aggregate (G): Takarazuka (specific gravity 2.61) Water (W) Cement admixture was added in the amounts shown in Table 2. Table 2 shows the test results of the concrete.

[0035]

[Table 2]

(Note) *: Addition amount to cement, wt% Example 2 With the same formulation as in Example 1, the compound (A) was produced by changing the monomer composition. Using this, a concrete test was conducted in the same manner as in Example 1. The test results are shown in Table 3.

[0037]

[Table 3]

(Note) *: Addition amount to cement, weight%

[0039]

EFFECTS OF THE INVENTION From the examples, the product of the present invention in which the compound (A) having a phenol skeleton and the polyol (B) are used in combination has markedly improved initial strength and long-term strength as compared with the case where only the compound (A) is used. It is clear that this is done. INDUSTRIAL APPLICABILITY According to the present invention, it is possible to remove concrete from a mold at an early stage, and it is also possible to increase long-term strength showing durability of concrete.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C04B 24/38 Z 2102-4G

Claims (3)

[Claims] 1. A compound (A) having a phenol skeleton and a polyol (B), wherein (A) / (B) is in a weight ratio of from 80/20.
Cement admixture characterized by being 99/1. 2. A compound (A) having a phenol skeleton, wherein the compound (A) is at least one phenol selected from the group of compounds represented by the following general formula (a), or a derivative thereof, or a general formula thereof.
A condensate obtained by condensing or co-condensing one or more compounds selected from the group consisting of melamine represented by (b) or a derivative thereof and urea with formaldehyde in the presence of an amino-based polymerization terminator. The cement admixture according to claim 1. General formula (a) Here, X ₃ is selected from the group consisting of hydrogen, a lower alkyl group having 1 to 3 carbon atoms, 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. General formula (b) Here, X ₄ is selected from hydrogen, hydroxyl group and —CH ₂ SO ₃ M ₁ , and M ₁ means hydrogen or an alkali metal. X ₅ is hydrogen, hydroxyl group,
Selected from —CH ₂ SO ₃ M ₂ , M ₂ means hydrogen or an alkali metal. X ₆ is selected from hydrogen, hydroxyl group, -CH ₂ SO ₃ M ₃ , and M ₃
Means hydrogen or an alkali metal. 3. An amino-based polymerization terminator having the following general formula (c):
The cement admixture according to claim 2, which is one or more compounds selected from the group of compounds represented by, (d), (e) and (f). General formula (c) Here, X ₁ is hydrogen, a lower alkyl group having 1 to 3 carbon atoms, 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, Y ₁ is a carboxyl group Or an alkali metal salt thereof, a sulfone group or an alkali metal salt thereof. General formula (d) Here, X ₂ is hydrogen, a lower alkyl group having 1 to 3 carbon atoms, 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, Y ₂ is a carboxyl group Or an alkali metal salt thereof, a sulfone group or an alkali metal salt thereof. General formula (e) Here, Z is hydrogen, a lower alkyl group having 1 to 3 carbon atoms,
It is selected from CH ₂ SO ₃ M ₅ , and M ₄ and M ₅ mean hydrogen or an alkali metal. Formula _{(f) H 2 NSO 3 M} 6 wherein M ₆ represents a hydrogen or an alkali metal.