JPH0826800A - Cement admixture - Google Patents

Abstract

(57) [Summary] [Structure] A co-condensation product of one or more compounds (a) selected from the compounds represented by the following general formula (A) with a substance (b) capable of co-condensing formaldehyde. Alternatively, a cement admixture containing a salt thereof as a main component. Embedded image (In the formula, R ₁ represents hydrogen or a linear or branched alkyl group having 1 to 3 carbon atoms, AO represents an oxyalkylene group having 2 to 3 carbon atoms, and n represents an integer of 100 to 300.) [Effect] When added to the cement composition, the work of filling the formwork becomes easy even in the case of concrete having a low water content. Moreover, since it is possible to remove the mold from the mold early, rationalization of construction is expected.

Description

Detailed Description of the Invention

[0001]

This invention relates to cement admixtures. More specifically, the present invention relates to a cement admixture that improves fluidity and hardening retardation 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, naphthalenesulfonic acid formaldehyde condensate salt (hereinafter referred to as naphthalene type), melamine sulfonic acid formaldehyde condensate salt (hereinafter referred to as melamine type), poly Carboxylic 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 has a problem that the retardation of hardening of concrete having excellent dispersibility is large, and the naphthalene type and melamine type have excellent curing characteristics, but the dispersibility is inferior to that of the polycarboxylic acid type. There is a limit to liquidity in the low water volume region.

[0004]

As a result of intensive studies, the inventors of the present invention have clarified the characteristics of various surfactants (including a dispersant) with respect to concrete, and have made clear from the findings. By designing the structure of the admixture, we have completed an admixture with extremely small dispersion characteristics and curing delay that cannot be obtained with existing dispersants.

That is, the present invention provides a cocondensation product of one or more compounds (a) selected from the compounds represented by the following general formula (A) with a formaldehyde cocondensable substance (b). Alternatively, it relates to a cement admixture containing a salt thereof as a main component.

[0006]

Embedded image

(Wherein R _{1 is} hydrogen or a linear or branched alkyl group having 1 to 3 carbon atoms AO: an oxyalkylene group having 2 to 3 carbon atoms, n is an integer of 100 to 300.) The present invention With respect to the dispersion mechanism and the curing property, the inventors have made a molecular design by paying attention to the dispersion mechanism by the steric barrier and the adsorption property for cement, and have completed a formaldehyde condensation-type admixture.

[0008] That is, in the study conducted by the present inventors, it was confirmed that the steric barrier dispersion mechanism of oxyalkylene groups is effective for dispersion, and that the amount of functional groups is small for curing characteristics. From the findings of the above, we determined the optimum range of the chain length of the alkylene group and the amount of functional groups, and
It was discovered that a cocondensation system using a long-chain alkylene oxide in the 0 molar range satisfies both dispersion and curing properties.

The compound represented by the general formula (A) is a polyoxyalkylene alkylphenol, and, for example, oxy to phenol, cresol (including isomers of ortho, meta, para, etc.), ethylphenol, etc. It is an adduct of 100 to 300 mol of alkylene group.

Considering the long-chain oxyalkylene group addition reaction and the cocondensation reaction, the alkylene oxide adduct of phenol is particularly preferable.

Further, when the oxyalkylene group is in the range of 110 to 200 mol, both the dispersibility and the curing property are excellent.

When the oxyalkylene group is less than 100, the curing retarding property is large, and when it exceeds 300, the amount of the functional group per cocondensation system becomes too small and the adsorptivity is decreased, so that the dispersibility tends to be decreased.

The oxyalkylene group having 2 to 3 carbon atoms is
Means ethylene oxide, propylene oxide,
The shape may be random or block, and is not limited.

The substance capable of co-condensation used in the present invention is preferably a benzene ring derivative or a naphthalene ring derivative, for example, alkylphenol or its sulfonic acid,
Aniline sulfonic acid, alkyl benzene sulfonic acid, alkyl naphthalene sulfonic acid, bisphenol sulfonate, and the like. Phenol, cresol (including isomers such as ortho, meta, para, etc.), or these sulfonic acids, aniline sulfonic acid , Benzenesulfonic acid, toluenesulfonic acid, naphthalenesulfonic acid and the like.

Considering the co-condensability among these, one or more selected from the compounds represented by the following general formula (B) which is a phenol derivative are particularly preferable.

[0016]

[Chemical 4]

(In the formula, R _{2 represents} hydrogen or a linear or branched alkyl group having 1 to 3 carbon atoms R ₃ represents hydrogen or a sulfone group.) An example of the compound represented by the general formula (B) Specific examples thereof include phenol, cresol (including isomers such as ortho, meta, and para), or a sulfonic acid thereof. Of these, phenolsulfonic acid is particularly preferable from the viewpoint of cocondensation property and performance. Cresols have a high condensation rate and tend to be a single condensation.

The co-condensation reaction is produced by an ordinary formaldehyde reaction carried out in an aqueous reaction under acidic conditions. This 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 neutralizing salts include monovalent metal salts, divalent metal salts, ammonium salts, amine salts and substituted amine salts. A neutral salt with sodium hydroxide is preferably used in terms of cost and production.

The reaction molar ratio of co-condensation is (a)
The range of / (b) = 1/99 to 50/50 is suitable, and 5/95 to
The range of 30/70 is particularly excellent in dispersibility and curing characteristics.

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

Charge a predetermined amount of (a) and (b) into a reaction vessel,
It can be obtained by dropping a predetermined amount of formalin water over 1 to 4 hours under stirring at 70 to 90 ° C., dropping and then stirring under reflux for 3 to 30 hours to cool and neutralize.

In the co-condensation system, the condensation viscosity and the condensation time are adjusted by the amount of water for condensation in the reaction system. Further, the reaction is under acidic condition due to the aromatic sulfonic acid and the unreacted acid contained therein, and 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 10,000 to 50,000.

The amount of the cocondensation product 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 amount of active ingredient with respect to cement.

When using the cocondensate of the present invention, a defoaming agent can be used in combination to adjust the amount of entrained air required for the concrete composition. A known antifoaming agent is used for adjusting the predetermined air amount, and is not particularly limited. For example,
A silicon-based defoaming agent containing dimethylpolysiloxane as a main component is used. Examples thereof include Silicon KM-73A (manufactured by Shin-Etsu Chemical Co., Ltd.) and Antifoam E-20 (manufactured by Kao Corporation). Also, as a defoaming agent, a fatty acid ester type such as Folex Rex 797 (manufactured by Nichika Kagaku Co., Ltd.)
(Manufactured by Kao Corporation) and the like.

The antifoaming agent is added in an amount of about 0.01 to 5% by weight (solid content) based on the active ingredient of the cocondensation product. Not limited.

Further, a bubble entraining agent can be used to adjust the predetermined amount of air. A known surfactant is used as the air bubble entraining agent and is not particularly limited. As an example, a resin acid salt (Vinsol; manufactured by Yamamune Chemical Co., Ltd.), polyoxyalkylene alkyl ether (Mighty AE-03, manufactured by Kao Co., Ltd.) and the like can be mentioned.

The amount of the air bubble entraining agent used is about 0.001 to 1% by weight (solid content) based on the active ingredient of the cocondensate, and a predetermined amount of air is used as in the case of the antifoaming agent. Therefore, the amount used is not limited. Therefore, there is a case where neither the defoaming agent nor the bubble entraining agent is used, or each is used or both are used, and the use is not limited.

The cement admixture of the present invention can be used in combination with other dispersants. The dispersant may be one generally used as an admixture for concrete, but it is a naphthalene sulfonate formaldehyde condensate, a melamine sulfonate formaldehyde condensate, a polycarboxylic acid or its ester or its salt, a purified lignosulfone. Acid or its salt, polystyrene sulfonate, cement dispersant having phenol skeleton (for example, formaldehyde co-condensate with other monomer copolymerizable with phenol sulfonic acid), cement containing aniline sulfonic acid as a main component What is conventionally called a high-performance water reducing agent, such as a dispersant (for example, a formaldehyde cocondensation product with another monomer capable of cocondensing with anilinesulfonic acid), is preferably used.

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

The admixture of the present invention can be used in combination with known additives (materials). One example is AE
Agent, AE water reducing agent, superplasticizer, high-performance water reducing agent, retarder, early strengthening agent, accelerator, foaming agent, water retention agent, thickener, waterproofing agent, water-soluble polymer, various surfactants, cement, etc. A hydraulic composition using paste mortar, various cements constituting concrete, blast furnace slag, fly ash, silica fume and the like can be mentioned.

[0033]

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

The molecular weight in the examples represents the molecular weight by weight average molecular weight (gel permeation chromatography / sodium polystyrene sulfonate conversion).

The contents of the aromatic compound (a) and aromatic compound (b) used in the examples are shown below.

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 110 mol adduct A-2; Phenol EO 150 mol adduct A-3; Orthocresol EO 170 mol adduct A-4; Phenol EO 250 mol adduct A-5; Phenol EO 250 mol / PO 20 mol block adduct A-6 (comparative); Phenol EO 80 mol adduct A-7 (comparative); Phenol EO 360 mol adduct Aromatic compound (b) B-1 Phenol sulfonic acid B-2; Para-cresol sulfonic acid B-3; Naphthalene sulfonic acid B-4; Phenol A production example of a cocondensate is shown below. Production Example 1 0.3 mol of A-1, 0.7 mol of B-1 and 4 mol of water were charged into a reaction vessel equipped with a stirrer, and 0.9 mol of 37% formaldehyde was added dropwise at 80 ° C. for 3 hours. After the dropping, raise the temperature to 105 ° C, react for 10 hours, cool, and add 50% sodium hydroxide.
Adjust the pH to 8 and add water to adjust the solid content to 30%,
A cocondensate having a molecular weight of 13,000 was obtained.

Production Example 2 0.2 mol of A-2, 0.8 mol of B-2 and 5 mol of water were charged into a reaction vessel equipped with a stirrer, and 0.9 mol of 37% formaldehyde was added dropwise at 80 ° C. for 3 hours. After the dropping, raise the temperature to 105 ° C, react for 12 hours, cool, and add 50% sodium hydroxide.
The pH was adjusted to 8 and water was added to adjust the solid content to 30% to obtain a cocondensate having a molecular weight of 22,000.

Production Example 3 A reaction vessel equipped with a stirrer was charged with 0.1 mol of A-1, 0.9 mol of B-1 and 6 mol of water, and 0.9 mol of 37% formaldehyde was added dropwise at 80 ° C. over 3 hours. After the dropping, raise the temperature to 105 ° C, react for 10 hours, cool, and add 50% sodium hydroxide.
The pH was adjusted to 8 and water was added to adjust the solid content to 30% to obtain a cocondensate having a molecular weight of 25,000.

Preparation Example 4 A reaction vessel equipped with a stirrer was charged with 0.1 mol of A-2, 0.9 mol of B-2 and 4 mol of water, and 0.9 mol of 37% formaldehyde was added dropwise at 80 ° C. over 3 hours. After the dropping, raise the temperature to 105 ° C, react for 12 hours, cool, and add 50% sodium hydroxide.
The pH was adjusted to 8 and water was added to adjust the solid content to 30% to obtain a cocondensate having a molecular weight of 17,000.

Production Example 5 A reaction vessel equipped with a stirrer was charged with 0.1 mol of A-3, 0.9 mol of B-3 and 5 mol of water, and 0.9 mol of 37% formaldehyde was added dropwise at 80 ° C. for 3 hours. After the completion of dropping, the temperature was raised to 105 ° C, the reaction was carried out for 8 hours, and the mixture was cooled and washed with 50% sodium hydroxide.
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 27,000.

Production Example 6 A reaction vessel equipped with a stirrer was charged with 0.1 mol of A-1, 0.9 mol of B-3 and 5 mol of water, and 0.9 mol of 37% formaldehyde was added dropwise at 80 ° C. over 3 hours. After the completion of dropping, the temperature was raised to 105 ° C, the reaction was carried out for 8 hours, and the mixture was cooled and washed with 50% sodium hydroxide.
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 A reaction vessel equipped with a stirrer was charged with 0.1 mol of A-4, 0.9 mol of B-1 and 5 mol of water, and 0.9 mol of 37% formaldehyde was added dropwise at 80 ° C. over 3 hours. After the dropping, raise the temperature to 105 ° C, react for 12 hours, cool, and add 50% sodium hydroxide.
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 31,000.

Production Example 8 A reaction vessel equipped with a stirrer was charged with 0.1 mol of A-5, 0.9 mol of B-1 and 6 mol of water, and 0.9 mol of 37% formaldehyde was added dropwise at 80 ° C. over 3 hours. After the dropping, raise the temperature to 105 ° C, react for 15 hours, cool, and add 50% sodium hydroxide.
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 33,000.

Production Example 9 A reaction vessel equipped with a stirrer was charged with 0.15 mol of A-1, 0.75 mol of B-1, 0.1 mol of B-4 and 6 mol of water, and 0.9 mol of 37% formaldehyde was added dropwise at 80 ° C. for 3 hours. After the completion of dropping, the temperature was raised to 105 ° C, reacted for 15 hours, cooled, adjusted to pH 8 with 50% sodium hydroxide, and added with water to give a solid content of 20%.
To obtain a cocondensate having a molecular weight of 42,000.

Production Example 10 (Comparative Example) In a reaction vessel equipped with a stirrer, 0.2 mol of A-6, 0.9 mol of B-1 and 6 mol of water were charged, and 0.9 mol of 37% formaldehyde was added dropwise at 80 ° C. for 3 hours. After the dropping, raise the temperature to 105 ° C, react for 25 hours, cool, and add 50% sodium hydroxide.
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 14,000.

Production Example 11 (Comparative Example) A-7 0.1 mol of A-7, 0.9 mol of B-1 and 8 mol of water were charged in a reaction vessel equipped with a stirrer, and 0.9 mol of 37% formaldehyde was added dropwise at 80 ° C. for 3 hours. After completion of the dropping, the temperature was raised to 105 ° C, reacted for 18 hours, cooled, and dried with 50% sodium hydroxide.
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 42,000.

Contents of the dispersant used in the comparative examples / symbols of the examples NS; naphthalene admixture (Mighty 150; Kao Corporation)
PC) Polycarboxylic acid admixture (Mighty 2000WHZ; manufactured by Kao Co., Ltd.) Table 1 shows the mixing conditions of concrete to be evaluated as a cement admixture .

[0049]

[Table 1]

Manufacture of concrete was adjusted by kneading the concrete materials shown in Table 1 and a cement admixture for 3 minutes with a forced mixer (manufactured by Taikai Kiko Co., Ltd.) for 3 minutes. The admixture was added so that the initial slump value was 20 ± 1 cm. The amount of air was adjusted with or without the addition of the bubble entraining agent and the defoaming agent so that the air amount was 4 ± 1%.

Foam entraining agent and defoaming agent used Defoaming agent; Folex Rex 797 (manufactured by Nichika Chemical Co., Ltd.) Foam entraining agent; Vinsol (manufactured by Yamasou Chemical Co., Ltd.) Measurement item Slump value; Table 2 shows the measurement results of ASTM C403-61T air volume; JIS A 1128 method.

[0052]

[Table 2]

(Evaluation Results) As shown in Table 2, the admixture of the present invention was able to obtain fluidity with a smaller addition amount than the comparative product.
Moreover, the curing time is fast. That is, it has an excellent flow effect and a remarkable effect on the curing characteristics.

[0054]

The cement admixture according to the present invention is excellent in dispersibility and hardening characteristics. Therefore, when it is added to the cement composition, the work of filling the mold with the low water content concrete becomes easy. Moreover, since it is possible to remove the mold from the mold early, rationalization of construction is expected.

Claims (10)

[Claims] 1. A cocondensation product of one or more compounds (a) selected from the compounds represented by the following general formula (A) with a formaldehyde cocondensable substance (b) or its neutralization: Cement admixture containing salt as the main component. Embedded image (In the formula, R _{1 represents} hydrogen or a linear or branched alkyl group having 1 to 3 carbon atoms AO: an oxyalkylene group having 2 to 3 carbon atoms n: represents an integer of 100 to 300.) 2. The cement admixture according to claim 1, wherein n in the general formula (A) is 110 to 200. 3. A substance capable of co-condensing formaldehyde,
The cement admixture according to claim 1 or 2, which is a benzene ring derivative or a naphthalene ring derivative. 4. A substance capable of co-condensing formaldehyde,
1 selected from compounds represented by the following general formula (B)
1 or 2 or more types.
The cement admixture described. Embedded image (In the formula, R _{2 represents} hydrogen or a linear or branched alkyl group having 1 to 3 carbon atoms R ₃ : represents hydrogen or a sulfone group.) 5. The cement admixture according to claim 4, wherein the compound represented by the general formula (B) is phenolsulfonic acid. 6. The reaction composition ratio of one or more kinds (a) selected from the compounds represented by the general formula (A) and the formaldehyde co-condensable substance (b) is (a) / (b) = 1/99
50 to 50 (molar ratio).
The cement admixture according to any one of 5 above. 7. The cement admixture according to claim 1, wherein the neutralized salt of the cocondensate is a monovalent metal salt, a divalent metal salt, an ammonium salt, an amine salt or a substituted amine salt. Agent. 8. The weight average molecular weight of the cocondensate (gel permeation chromatography / sodium polystyrene sulfonate conversion) is 3,000 to 100,000.
The cement admixture according to any one of 7 above. 9. The cement admixture according to claim 1, wherein the cement admixture is used in combination with an antifoaming agent. 10. The cement admixture according to claim 1, which is used in combination with an air bubble entraining agent.