CN111978500A - Melamine water reducing agent and preparation method thereof - Google Patents
Melamine water reducing agent and preparation method thereof Download PDFInfo
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- CN111978500A CN111978500A CN202010898839.7A CN202010898839A CN111978500A CN 111978500 A CN111978500 A CN 111978500A CN 202010898839 A CN202010898839 A CN 202010898839A CN 111978500 A CN111978500 A CN 111978500A
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- melamine
- reducing agent
- aqueous solution
- water reducing
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G12/00—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen
- C08G12/02—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes
- C08G12/40—Chemically modified polycondensates
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
- C04B24/16—Sulfur-containing compounds
- C04B24/161—Macromolecular compounds comprising sulfonate or sulfate groups
- C04B24/166—Macromolecular compounds comprising sulfonate or sulfate groups obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G12/00—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen
- C08G12/02—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes
- C08G12/26—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with heterocyclic compounds
- C08G12/30—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with heterocyclic compounds with substituted triazines
- C08G12/32—Melamines
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/30—Water reducers, plasticisers, air-entrainers, flow improvers
- C04B2103/302—Water reducers
Abstract
The invention relates to a melamine water reducing agent and a preparation method thereof, belonging to the technical field of chemical synthesis. The used raw materials comprise the following components in parts by weight: 15-25.5 parts of melamine, 38-43 parts of 38% formaldehyde aqueous solution, 10-23 parts of sodium thiosulfate, 1-2 parts of citric acid, 5-8 parts of 40% potassium carbonate aqueous solution and 30-45 parts of water. The invention shortens the preparation period of the process by changing the feeding sequence. Compared with the existing production process, the preparation method provided by the invention shortens the reaction time by more than 4 hours. The invention avoids using strong corrosive chemicals such as concentrated sulfuric acid, sodium hydroxide and the like, ensures the safety of workers while producing, and reduces the risk of safety accidents.
Description
Technical Field
The invention belongs to the technical field of chemical synthesis, and particularly relates to a melamine water reducing agent and a preparation method thereof.
Background
The water reducing agent is a concrete admixture capable of reducing the water consumption for mixing under the condition of maintaining the slump constant of concrete basically. Common water reducing agents include the following: lignosulfonate water reducing agent, naphthalene water reducing agent, melamine water reducing agent, sulfamate water reducing agent, aliphatic water reducing agent, polycarboxylic acid water reducing agent and the like. The melamine water reducer has strong adsorption and dispersion effects on cement, and is one of the water reducers with better comprehensive indexes in the existing concrete water reducers. In addition, the melamine water reducer has good compatibility, can be used in combination with other types of water reducers, and is used for adjusting the comprehensive properties of other water reducers.
The synthesis method of the melamine water reducing agent adopts a four-step synthesis method. The first step is hydroxymethylation reaction, and melamine and formaldehyde are used as raw materials to prepare trimethylol melamine; the second step is sulfonation reaction, the methylol melamine reacts with sulfonating agent under alkaline condition to obtain melamine sulfonate with high sulfonation degree; the third step is acid polycondensation, the monosulfonate of sulfonation reaction is reacted at a lower pH value and a certain temperature, hydroxymethyl groups can be condensed to generate melamine formaldehyde sulfonate with ether bonds, and relative molecular mass is rapidly increased; the fourth step is alkaline reforming reaction, which is generally carried out for 1-2 hours at 70-80 ℃ under alkaline conditions. In the existing synthesis method, the problems of more reaction steps, long reaction time, strict control of reaction conditions in each step and the like exist, so that the problems of long period and high production cost of synthesizing the water reducing agent are caused, and the problems of strong corrosivity and the like of reagents used in the preparation process cause harm to the personal safety of workers and the environment.
Disclosure of Invention
Aiming at the problems of long production period and great harm of used reagents to human and environment in the prior art, the invention provides a melamine water reducing agent and a preparation method thereof, aiming at solving the problems. The water reducing agent is in a liquid state, is an anionic non-air-entraining type high-efficiency water reducing agent, and is environment-friendly. The invention changes the feeding sequence of the reaction, adopts the preparation process similar to the one-pot method, effectively reduces the preparation steps and shortens the preparation period of the process.
The melamine water reducing agent comprises the following raw materials in parts by weight: 15-25.5 parts of melamine, 38-43 parts of 38% formaldehyde aqueous solution, 10-23 parts of sodium thiosulfate, 1-2 parts of citric acid, 5-8 parts of 40% potassium carbonate aqueous solution and 30-45 parts of water.
Preferably, the raw materials comprise the following components in parts by weight: 25.5 parts of melamine, 43 parts of 38% formaldehyde aqueous solution, 23 parts of sodium thiosulfate, 2 parts of citric acid, 8 parts of 40% potassium carbonate aqueous solution and 42 parts of water.
Preferably, the raw material comprises 0.4 part of dimethyl sulfoxide.
A preparation method of a melamine water reducing agent comprises the following specific steps:
(1) sequentially adding water and dimethyl sulfoxide into a reaction kettle, sequentially adding melamine, 38% formaldehyde water solution and sodium thiosulfate while stirring, and stirring and heating for reaction for 1-2 hours;
(2) after the reaction is finished, slowly dropwise adding 40% potassium carbonate aqueous solution into the reaction liquid to adjust the pH of the reaction liquid to be alkaline;
(3) and adding citric acid into the reaction liquid to neutralize the reaction liquid, wherein the pH value of the reaction liquid is 7-8, and cooling to 20-30 ℃ to obtain the liquid melamine water reducing agent.
Preferably, the reaction temperature in the step (1) is 75-80 ℃.
Preferably, the temperature of the 40% potassium carbonate aqueous solution dropwise added in the step (2) is 75-80 ℃.
Preferably, the pH value in the step (2) is more than or equal to 12.
Preferably, the time for dripping the 40% potassium carbonate aqueous solution in the step (2) is not less than 1 h.
The invention has the beneficial effects that:
(1) the invention changes the feeding sequence, adopts the preparation process similar to the one-pot method, effectively reduces the preparation steps and shortens the preparation period of the process. Compared with the existing production process, the preparation method provided by the invention shortens the reaction time by more than 4 hours.
(2) Compared with the existing preparation method, the preparation method avoids using strong corrosive chemicals such as concentrated sulfuric acid, sodium hydroxide and the like, ensures the safety of workers while producing, reduces the risk of safety accidents, and almost has no corrosion to metal; and the used raw materials are simple and easy to obtain.
Detailed Description
In order to make those skilled in the art better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
A preparation method of a melamine water reducing agent comprises the following raw materials: 25.5 parts of melamine, 43 parts of 38% formaldehyde aqueous solution, 23 parts of sodium thiosulfate, 2 parts of citric acid, 8 parts of 40% potassium carbonate aqueous solution, 42 parts of water and 0.4 part of dimethyl sulfoxide.
The method comprises the following specific steps:
(1) adding 45 parts of water and 0.4 part of dimethyl sulfoxide into a reaction kettle in sequence, adding 25.5 parts of melamine, 40 parts of 38% formaldehyde aqueous solution and 23 parts of sodium thiosulfate into the reaction kettle in sequence under stirring, and heating to 80 ℃ under stirring to react for 2 hours;
(2) after the reaction is finished, controlling the temperature to be 80 ℃, slowly dripping 6 parts of 40% potassium carbonate aqueous solution into the reaction solution to adjust the pH of the reaction solution to be 12, wherein the dripping time is 1 h;
(3) and adding citric acid into the reaction solution to neutralize the reaction solution, wherein the pH value of the reaction solution is 7, and cooling to 25 ℃ to obtain the melamine water reducing agent.
Example 2
A preparation method of a melamine water reducing agent comprises the following raw materials: 18 parts of melamine, 37.5 parts of 38% formaldehyde aqueous solution, 10 parts of sodium thiosulfate, 1 part of citric acid, 5 parts of 40% potassium carbonate aqueous solution, 30 parts of water and 0.4 part of dimethyl sulfoxide.
The method comprises the following specific steps:
(1) adding 30 parts of water and 0.4 part of dimethyl sulfoxide into a reaction kettle in sequence, adding 18 parts of melamine, 37.5 parts of 38% formaldehyde aqueous solution and 10 parts of sodium thiosulfate into the reaction kettle in sequence under stirring, and heating the mixture to 75 ℃ under stirring to react for 1 hour;
(2) after the reaction is finished, controlling the temperature to be 80 ℃, slowly dripping 5 parts of 40% potassium carbonate aqueous solution into the reaction solution to adjust the pH of the reaction solution to be 12, wherein the dripping time is 1 h;
(3) and adding citric acid into the reaction solution to neutralize the reaction solution, wherein the pH value of the reaction solution is 8, and cooling to 30 ℃ to obtain the melamine water reducing agent.
Example 3
A preparation method of a melamine water reducing agent comprises the following raw materials: 21 parts of melamine, 33 parts of 38% formaldehyde aqueous solution, 17 parts of sodium thiosulfate, 1.5 parts of citric acid, 5 parts of 40% potassium carbonate aqueous solution, 37 parts of water and 0.4 part of dimethyl sulfoxide.
The method comprises the following specific steps:
(1) adding 37 parts of water and 0.4 part of dimethyl sulfoxide into a reaction kettle in sequence, adding 21 parts of melamine, 33 parts of 38% formaldehyde aqueous solution and 17 parts of sodium thiosulfate into the reaction kettle in sequence under stirring, and heating the mixture to 75 ℃ under stirring to react for 1 hour;
(2) after the reaction is finished, controlling the temperature to be 80 ℃, slowly dripping 5 parts of 40% potassium carbonate aqueous solution into the reaction solution to adjust the pH of the reaction solution to be 12, wherein the dripping time is 1 h;
(3) and adding citric acid into the reaction solution to neutralize the reaction solution, wherein the pH value of the reaction solution is 8, and cooling to 25 ℃ to obtain the melamine water reducing agent.
Comparative example
A preparation method of a melamine water reducing agent comprises the following specific steps:
(1) adding 25 parts of melamine and 15 parts of 38% aqueous formaldehyde solution into 40 parts of water, adjusting the pH value of a reaction solution to 11 by using a 30% aqueous sodium hydroxide solution, and heating to 60 ℃ for reacting for 1h to obtain a trimethylol melamine solution;
(2) adding 22.5 parts of sodium bisulfite into the trimethylol melamine solution obtained in the step (1), controlling the pH of a reaction solution to be 11-12, and heating to 80 ℃ for reaction for 3 hours to obtain a melamine sulfonate solution;
(3) controlling the temperature of the reaction solution obtained in the step (2) at 80 ℃, adjusting the pH of the reaction solution to 3 by using concentrated sulfuric acid, and carrying out heat preservation reaction for 6 hours to obtain a polycondensate solution;
(4) and (4) dropwise adding 30 aqueous sodium hydroxide solution into the polycondensate solution obtained in the step (3) to adjust the pH of the reaction solution to 8, and cooling to 25 ℃ to obtain the melamine water reducer.
The water reducing agents prepared in example 1, example 2, example 3 and comparative example were applied to concrete respectively, and then the performance of the concrete was tested, and the test results are shown in the following table 1:
TABLE 1 test data
From the detection results, the average mass solid content of the water reducer is 51.23% in the embodiments 1, 2 and 3, which is 1.5 times higher than that of the conventional common melamine water reducer; the amount of ammonia released was within the standard; the setting time of the concrete can be shortened by 20 days compared with that of the common melamine water reducing agent; compressive strength ratio R7+28Is 1.2 times higher than the common melamine water reducing agent. Only from the three indexes, the product of the invention can shorten the construction period, save water and ensure the building quality and the earthquake resistance (common civil buildings relate to 7-8-level earthquake resistance) during construction and application. Therefore, the water reducing agent prepared by the invention has an effect obviously superior to that of the existing water reducing agent after being applied to concrete.
Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made on the embodiments of the present invention by those skilled in the art without departing from the spirit and scope of the present invention, and these modifications or substitutions are within the scope of the present invention/any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (8)
1. The melamine water reducing agent is characterized by comprising the following raw materials in parts by weight: 15-25.5 parts of melamine, 38-43 parts of 38% formaldehyde aqueous solution, 10-23 parts of sodium thiosulfate, 1-2 parts of citric acid, 5-8 parts of 40% potassium carbonate aqueous solution and 30-45 parts of water.
2. The melamine water reducer of claim 1, wherein the raw materials comprise the following components in parts by weight: 25.5 parts of melamine, 43 parts of 38% formaldehyde aqueous solution, 23 parts of sodium thiosulfate, 2 parts of citric acid, 8 parts of 40% potassium carbonate aqueous solution and 42 parts of water.
3. A melamine based water reducer according to claim 1 or 2, characterized in that the raw material comprises 0.4 parts of dimethyl sulfoxide.
4. A preparation method of a melamine water reducing agent is characterized by comprising the following steps:
(1) sequentially adding water and dimethyl sulfoxide into a reaction kettle, sequentially adding melamine, 38% formaldehyde water solution and sodium thiosulfate while stirring, and stirring and heating for reaction for 1-2 hours;
(2) after the reaction is finished, slowly dropwise adding 40% potassium carbonate aqueous solution into the reaction liquid to adjust the pH of the reaction liquid to be alkaline;
(3) and adding citric acid into the reaction liquid to neutralize the reaction liquid, wherein the pH value of the reaction liquid is 7-8, and cooling to 20-30 ℃ to obtain the melamine water reducing agent.
5. The preparation method of the melamine water reducing agent according to claim 4, wherein the reaction temperature in the step (1) is 75-80 ℃.
6. The preparation method of the melamine water reducer according to claim 4, wherein the temperature of the 40% potassium carbonate aqueous solution dropwise added in the step (2) is 75-80 ℃.
7. The method for preparing the melamine water reducing agent according to claim 4, wherein the pH value in the step (2) is not less than 12.
8. The method for preparing the melamine water reducing agent according to claim 4, wherein the time for dripping the 40% potassium carbonate aqueous solution in the step (2) is not less than 1 h.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010898839.7A CN111978500A (en) | 2020-08-31 | 2020-08-31 | Melamine water reducing agent and preparation method thereof |
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| CN202010898839.7A CN111978500A (en) | 2020-08-31 | 2020-08-31 | Melamine water reducing agent and preparation method thereof |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09302057A (en) * | 1996-05-09 | 1997-11-25 | Nissan Chem Ind Ltd | Production of aqueous solution of water-reducing agent |
| CA2287423A1 (en) * | 1998-10-23 | 2000-04-23 | Nissan Chemical Industries, Ltd. | Process for preparing an aqueous solution of sulfanilic acid modified melamine-formaldehyde resin and a cement composition |
| CN1756724A (en) * | 2003-03-05 | 2006-04-05 | 株式会社日本触媒 | Cement admixture, cement composition and method for laying work the same, and method for producing cement hardened product |
| CN102304211A (en) * | 2011-05-27 | 2012-01-04 | 江苏博特新材料有限公司 | Sulfonated melamine-formaldehyde polycondensate water reducer and preparation method thereof |
-
2020
- 2020-08-31 CN CN202010898839.7A patent/CN111978500A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09302057A (en) * | 1996-05-09 | 1997-11-25 | Nissan Chem Ind Ltd | Production of aqueous solution of water-reducing agent |
| CA2287423A1 (en) * | 1998-10-23 | 2000-04-23 | Nissan Chemical Industries, Ltd. | Process for preparing an aqueous solution of sulfanilic acid modified melamine-formaldehyde resin and a cement composition |
| CN1756724A (en) * | 2003-03-05 | 2006-04-05 | 株式会社日本触媒 | Cement admixture, cement composition and method for laying work the same, and method for producing cement hardened product |
| CN102304211A (en) * | 2011-05-27 | 2012-01-04 | 江苏博特新材料有限公司 | Sulfonated melamine-formaldehyde polycondensate water reducer and preparation method thereof |
Non-Patent Citations (3)
| Title |
|---|
| HUANG, YC，等: "SYNTHESIS AND PROPERTIES OF HIGH-SULFONATED MELAMINE-FORMALDEHYDE RESIN", 《JOURNAL OF APPLIED POLYMER SCIENCE》 * |
| 沈晓雷: "高效减水剂用对氨基苯磺酸-三聚氰胺-甲醛树脂的合成", 《中国胶粘剂》 * |
| 赵玉庭，等: "《复合材料聚合物基体》", 31 July 1992, 武汉工业大学出版社 * |
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