CN105837724A - Preparation method for aliphatic water reducer compounded with polycarboxylate superplasticizer - Google Patents

Abstract

The invention discloses a method for preparing an aliphatic water-reducer compounded with a polycarboxylate water-reducer, and relates to the field of concrete admixtures. The aliphatic water-reducer prepared by the invention has anti-mud effect and can be combined with polycarboxylate The water reducing agent is compounded in any proportion, and the dispersion performance of the compounded water reducing agent is obviously improved. Under the condition of constant dosage, the concrete has better slump retention performance and strength, which prolongs the use of concrete It solves the problems of poor dispersibility and rapid collapse of polycarboxylate superplasticizers caused by high mud content in concrete sand and gravel materials. The raw materials of the invention have a wide range of sources, the preparation method is simple, and there is no discharge of pollutants such as three wastes during the preparation process. Suitable for industrialized mass production.

Description

A kind of preparation method of aliphatic water reducer compounded with polycarboxylate water reducer

technical field

The invention relates to the field of concrete admixtures, in particular to a method for preparing an aliphatic water reducer compounded with a polycarboxylate water reducer.

Background technique

The third-generation water reducer in the building material industry is a high-performance water reducer represented by polycarboxylate, which is favored by the building material industry for its excellent performance of high water reduction, high slump retention and good environmental protection characteristics. While polycarboxylate superplasticizers are widely used in concrete engineering, some obvious defects have also been exposed. In recent years, due to the widespread use of high-performance concrete in construction projects, natural sand with good quality has almost been digested, and it is replaced by machine-made sand or natural sand with poor quality, which has a relatively high mud content. , has a great impact on the performance of polycarboxylate water reducer, resulting in poor concrete fluidity and large slump loss. Under such circumstances, it is necessary to develop a new type of water reducing agent, or develop an anti-mud additive to solve the problem in a targeted manner.

Contents of the invention

The object of the present invention is to provide a preparation method of an aliphatic water reducer with anti-mud function which is compounded with polycarboxylate water reducer.

To achieve the above object, the present invention is achieved through the following technical solutions:

A preparation method of an aliphatic water reducer compounded with a polycarboxylate water reducer, comprising the following steps:

1) Mix and dissolve the sodium salt and the initiator in water to prepare an aqueous solution with a mass fraction of 40%, stir evenly, and heat up to 35-50°C;

2) Mix formaldehyde, methacrolein, and cyclohexanone to obtain a mixed solution, which is equally divided into two parts, and added dropwise to the aqueous solution of step 1) twice, after the first drop is completed, stir evenly, and then Add the second part dropwise, and the time for each drop is controlled within 1.5-2h;

3) Warm up the solution after step 2) dropwise addition to 118°C-120°C, and keep it warm for 3-4h;

4) Cool down the solution in step 3) to 95°C-100°C, add a cross-linking agent, and stir and mix at this temperature for 30 minutes;

5) Prepare the alkenoic acid into an aqueous solution with a mass fraction of 30%-40%, and add the aqueous solution dropwise to the solution in step 4) at 95°C to 100°C, and control the dropping time within 0.5-1h, and keep warm 1.5-3h;

6) Cool down the solution in step 5) to 40°C-50°C, add a neutralizing agent, and adjust the pH to 4-6 to obtain the product.

Preferably, the sodium salt is sodium sulfite or sodium pyrosulfite.

Preferably, the alkenoic acid is methacrylic acid or acrylic acid.

Preferably, the molar ratio of sodium sulfite, formaldehyde, methacrolein, cyclohexanone and enoic acid is 1:3.7-4:1.7-1.9:1:1.3-1.5.

Preferably, the molar ratio of sodium metabisulfite, formaldehyde, methacrolein, cyclohexanone, and alkenoic acid is 0.7:3.7-4:1.7-1.9:1:1.3-1.5.

Preferably, the initiator in step 1) is 30% sodium hydroxide solution, accounting for 0.1%-0.4% of the total mass of the water reducer.

Preferably, the cross-linking agent in the step 4) is azobisisobutyronitrile, accounting for 0.03%-0.15% of the total mass of the water reducer.

Preferably, the neutralizing agent in step 6) is 98% formic acid, accounting for 5%-6% of the total mass of the water reducer.

Beneficial effects of the present invention: the aliphatic water-reducer prepared by the present invention has anti-mud effect, and can be compounded with polycarboxylate water-reducer in any proportion. The concrete has better slump retention performance and strength, prolongs the service life of concrete, and solves the problems of poor dispersion and rapid slump loss of polycarboxylate superplasticizers caused by high mud content in concrete sand and gravel. , the raw material source of the present invention is extensive, and preparation method is simple, does not discharge three wastes and other pollutants in the preparation process, and is suitable for industrialized mass production.

detailed description

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the present invention Examples, not all examples. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Example 1:

A preparation method of an aliphatic water reducer compounded with a polycarboxylate water reducer, comprising the following steps:

1) Sodium sulfite and 30% sodium hydroxide solution were mixed and dissolved in water to obtain an aqueous solution with a mass fraction of 40%, stirred evenly, and heated to 45°C;

2) Mix formaldehyde, methacrolein, and cyclohexanone to obtain a mixed solution, which is equally divided into two parts, and added dropwise to the aqueous solution of step 1) twice, after the first drop is completed, stir evenly, and then Add the second part dropwise, and control the time of each drop at 1.5h;

3) The temperature of the solution after the dropwise addition in step 2) is raised to 120° C., and kept for 3 hours;

4) Cool the solution in step 3) to 95°C, add azobisisobutyronitrile, and stir and mix at this temperature for 30 minutes;

5) Acrylic acid is prepared into an aqueous solution with a mass fraction of 40%, and the aqueous solution is added dropwise to the solution in step 4) at 95° C., the dropping time is controlled within 1 hour, and the temperature is kept for 2 hours;

6) Cool the solution in step 5) to 50° C., add 98% formic acid, and adjust the pH to 5 to obtain the product.

The molar ratio of sodium sulfite, formaldehyde, methacrolein, cyclohexanone and acrylic acid is 1:3.9:1.8:1:1.4.

The sodium hydroxide solution accounts for 0.3% of the total mass of the water reducer, the azobisisobutylcyanide accounts for 0.09% of the total mass of the water reducer, and the formic acid accounts for 5.5% of the total mass of the water reducer.

Example 2:

A preparation method of an aliphatic water reducer compounded with a polycarboxylate water reducer, comprising the following steps:

1) Sodium metabisulfite and 30% sodium hydroxide solution were mixed and dissolved in water to prepare an aqueous solution with a mass fraction of 40%, stirred evenly, and heated to 50°C;

2) Mix formaldehyde, methacrolein, and cyclohexanone to obtain a mixed solution, which is equally divided into two parts, and added dropwise to the aqueous solution of step 1) twice, after the first drop is completed, stir evenly, and then Add the second part dropwise, and the time for each drop is controlled at 1.5;

3) The temperature of the solution after the dropwise addition in step 2) is raised to 120° C., and kept for 3 hours;

4) Cool down the solution in step 3) to 95°C-100°C, add azobisisobutylcyanide, and stir and mix at this temperature for 30 minutes;

5) Prepare methacrylic acid into an aqueous solution with a mass fraction of 30%-40%, add the aqueous solution dropwise to the solution in step 4) at 95° C., control the dropping time within 1 hour, and keep warm for 2 hours;

6) Cool the solution in step 5) to 50° C., add 98% formic acid, and adjust the pH to 5 to obtain the product.

The molar ratio of sodium metabisulfite, formaldehyde, methacrolein, cyclohexanone, and methacrylic acid is 0.7:3.9:1.8:1:1.34.

The sodium hydroxide solution accounts for 0.3% of the total mass of the water reducer, the azobisisobutylcyanide accounts for 0.09% of the total mass of the water reducer, and the formic acid accounts for 5.5% of the total mass of the water reducer.

Example 3:

A preparation method of an aliphatic water reducer compounded with a polycarboxylate water reducer, comprising the following steps:

1) Sodium sulfite and 30% sodium hydroxide solution were mixed and dissolved in water to obtain an aqueous solution with a mass fraction of 40%, stirred evenly, and heated to 40°C;

2) Mix formaldehyde, methacrolein, and cyclohexanone to obtain a mixed solution, which is equally divided into two parts, and added dropwise to the aqueous solution of step 1) twice, after the first drop is completed, stir evenly, and then Add the second part dropwise, and control the time of each drop at 1.5h;

3) Warm up the solution after step 2) to 118° C. and keep it warm for 3.5 hours;

4) Cool the solution in step 3) to 95°C, add azobisisobutyronitrile, and stir and mix at this temperature for 30 minutes;

5) Prepare methacrylic acid into an aqueous solution with a mass fraction of 35%, and add the aqueous solution dropwise to the solution in step 4) at 100° C., the dropping time is controlled within 1 hour, and the temperature is kept for 2 hours;

6) Cool the solution in step 5) to 45° C., add 98% formic acid, and adjust the pH to 5 to obtain the product.

The molar ratio of sodium sulfite, formaldehyde, methacrolein, cyclohexanone and methacrylic acid is 1:4:1.8:1:1.5.

The sodium hydroxide solution accounts for 0.4% of the total mass of the water reducer, the azobisisobutylcyanide accounts for 0.13% of the total mass of the water reducer, and the formic acid accounts for 5% of the total mass of the water reducer.

Example 4:

A preparation method of an aliphatic water reducer compounded with a polycarboxylate water reducer, comprising the following steps:

1) Sodium sulfite and 30% sodium hydroxide solution were mixed and dissolved in water to obtain an aqueous solution with a mass fraction of 40%, stirred evenly, and heated to 50°C;

2) Mix formaldehyde, methacrolein, and cyclohexanone to obtain a mixed solution, which is equally divided into two parts, and added dropwise to the aqueous solution of step 1) twice, after the first drop is completed, stir evenly, and then Add the second portion dropwise, and the time for each addition is controlled within 2 hours;

3) The temperature of the solution after the dropwise addition in step 2) is raised to 120° C., and kept for 4 hours;

4) Cool the solution in step 3) to 100°C, add azobisisobutyronitrile, and stir and mix at this temperature for 30 minutes;

5) Acrylic acid is prepared into an aqueous solution with a mass fraction of 40%, and the aqueous solution is added dropwise to the solution in step 4) at 95° C., the dropping time is controlled within 0.5 h, and the temperature is kept for 3 h;

6) Cool the solution in step 5) to 40° C., add 98% formic acid, and adjust the pH to 6 to obtain the product.

The molar ratio of sodium sulfite, formaldehyde, methacrolein, cyclohexanone and acrylic acid is 1:3.7:1.7:1:1.4.

The sodium hydroxide solution accounts for 0.2% of the total mass of the water reducer, the azobisisobutylcyanide accounts for 0.05% of the total mass of the water reducer, and the formic acid accounts for 5.5% of the total mass of the water reducer.

Example 5:

A preparation method of an aliphatic water reducer compounded with a polycarboxylate water reducer, comprising the following steps:

1) Sodium metabisulfite and 30% sodium hydroxide solution were mixed and dissolved in water to prepare an aqueous solution with a mass fraction of 40%, stirred evenly, and heated to 35°C;

2) Mix formaldehyde, methacrolein, and cyclohexanone to obtain a mixed solution, which is equally divided into two parts, and added dropwise to the aqueous solution of step 1) twice, after the first drop is completed, stir evenly, and then Add the second part dropwise, and control the time of each drop at 1.5h;

3) The temperature of the solution after the dropwise addition in step 2) was raised to 118° C., and kept for 4 hours;

4) Cool the solution in step 3) to 100°C, add azobisisobutyronitrile, and stir and mix at this temperature for 30 minutes;

5) Acrylic acid is prepared into an aqueous solution with a mass fraction of 30%, and the aqueous solution is added dropwise to the solution in step 4) at 100° C., the dropping time is controlled within 1 hour, and the temperature is kept for 2 hours;

6) Cool the solution in step 5) to 45° C., add 98% formic acid, and adjust the pH to 5 to obtain the product.

The molar ratio of sodium metabisulfite, formaldehyde, methacrolein, cyclohexanone and acrylic acid is 0.7:3.7:1.7:1:1.3.

The sodium hydroxide solution accounts for 0.1% of the total mass of the water reducer, the azobisisobutyrocyanide accounts for 0.05% of the total mass of the water reducer, and the formic acid accounts for 5% of the total mass of the water reducer.

Embodiment 6:

A preparation method of an aliphatic water reducer compounded with a polycarboxylate water reducer, comprising the following steps:

1) Sodium metabisulfite and 30% sodium hydroxide solution were mixed and dissolved in water to prepare an aqueous solution with a mass fraction of 40%, stirred evenly, and heated to 50°C;

2) Mix formaldehyde, methacrolein, and cyclohexanone to obtain a mixed solution, which is equally divided into two parts, and added dropwise to the aqueous solution of step 1) twice, after the first drop is completed, stir evenly, and then Add the second portion dropwise, and the time for each addition is controlled within 2 hours;

3) The temperature of the solution after the dropwise addition in step 2) is raised to 120° C., and kept for 3 hours;

4) Cool the solution in step 3) to 95°C, add azobisisobutyronitrile, and stir and mix at this temperature for 30 minutes;

5) Prepare methacrylic acid into an aqueous solution with a mass fraction of 40%, and add the aqueous solution dropwise to the solution in step 4) at 95° C., the dropping time is controlled within 0.5 h, and the temperature is kept for 1.5 h;

6) Cool the solution in step 5) to 40° C., add 98% formic acid, and adjust the pH to 4 to obtain the product.

The molar ratio of sodium metabisulfite, formaldehyde, methacrolein, cyclohexanone, and methacrylic acid is 0.7:3.8:1.9:1:1.5.

The sodium hydroxide solution accounts for 0.4% of the total mass of the water reducer, the azobisisobutyrocyanide accounts for 0.15% of the total mass of the water reducer, and the formic acid accounts for 5% of the total mass of the water reducer.

Implementation case:

Compound the aliphatic water reducer prepared in Example 1 and Example 2 of the present invention with polycarboxylate water reducer at a mass ratio of 3:7 to obtain a compound water reducer with anti-mud effect, marked as No. 1 And No. 2, and its performance parameters were tested, and the effect experiment was carried out. The clean paste test was carried out in accordance with the national standard GB/T8077-2012 "Test Method for Uniformity of Concrete Admixtures", and montmorillonite was mixed in to replace the corresponding quality of cement. The mortar test is carried out according to the national standard GB/T 19671-1999 "Cement mortar strength test method", and the concrete performance test is carried out according to the national standard GB/T 50080-2002 "Test method for the performance of ordinary concrete mixture".

1. Pulp Fluidity Test

2. Fluidity experiment of mortar with montmorillonite superplasticizer

3. Concrete experiment

The concrete mix ratio is as follows:

The test results are as follows:

The above experimental results show that under the condition of the same aggregate mud content, the dispersion effect of the compound water reducer prepared by the present invention is obviously better than that of ordinary polycarboxylate water reducer, and the concrete slump is also maintained better.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is a relationship between these entities or operations. any such actual relationship or order exists between them. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be described in the foregoing embodiments Modifications are made to the recorded technical solutions, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (8)

1. A preparation method of an aliphatic water reducer compounded with a polycarboxylate water reducer, characterized in that it comprises the following steps: 1) Mix and dissolve the sodium salt and the initiator in water to prepare an aqueous solution with a mass fraction of 40%, stir evenly, and heat up to 35-50°C; 2) Mix formaldehyde, methacrolein, and cyclohexanone to obtain a mixed solution, which is equally divided into two parts, and added dropwise to the aqueous solution of step 1) twice, after the first drop is completed, stir evenly, and then Add the second part dropwise, and the time for each drop is controlled within 1.5-2h; 3) Warm up the solution after step 2) dropwise addition to 118°C-120°C, and keep it warm for 3-4h; 4) Cool down the solution in step 3) to 95°C-100°C, add a cross-linking agent, and stir and mix at this temperature for 30 minutes; 5) Prepare the alkenoic acid into an aqueous solution with a mass fraction of 30%-40%, and add the aqueous solution dropwise to the solution in step 4) at 95°C to 100°C, and control the dropping time within 0.5-1h, and keep warm 1.5-3h; 6) Cool down the solution in step 5) to 40°C-50°C, add a neutralizing agent, and adjust the pH to 4-6 to obtain the product. 2. The preparation method of the aliphatic water reducer compounded with polycarboxylate water reducer as claimed in claim 1, wherein the sodium salt is sodium sulfite or sodium pyrosulfite. 3. The preparation method of the aliphatic water reducer compounded with polycarboxylate water reducer as claimed in claim 1, characterized in that, the alkenoic acid is methacrylic acid or acrylic acid. 4. the preparation method of the aliphatic water reducer compounded with polycarboxylate water reducer as claimed in claim 2, is characterized in that, the sodium sulfite, formaldehyde, methacrolein, cyclohexanone, alkenoic acid The molar ratio is 1:3.7-4:1.7-1.9:1:1.3-1.5. 5. the preparation method of the aliphatic water reducer compounded with polycarboxylate water reducer as claimed in claim 2, is characterized in that, described sodium pyrosulfite, formaldehyde, methacrolein, cyclohexanone, alkenoic acid The molar ratio is 0.7:3.7-4:1.7-1.9:1:1.3-1.5. 6. the preparation method of the aliphatic water-reducer compounded with polycarboxylate water-reducer as claimed in claim 1, is characterized in that, described step 1) in initiator is 30% sodium hydroxide solution, accounts for 0.1% to 0.4% of the total mass of the water reducing agent. 7. the preparation method of the aliphatic water-reducer compounded with polycarboxylate water-reducer as claimed in claim 1, is characterized in that, described step 4) in cross-linking agent is azobisisobutylcyanide, accounts for 0.03% to 0.15% of the total mass of the water reducer. 8. The preparation method of the aliphatic water reducer compounded with polycarboxylate water reducer as claimed in claim 1, characterized in that, in the step 6), the neutralizer is 98% formic acid, accounting for 98% of the water reducer 5% to 6% of the total weight of the agent.