CN115651135A - High-water-reduction water reducer and preparation method thereof - Google Patents

Abstract

The invention discloses a preparation method of a high-water-reducing water-reducing agent, which comprises the following steps: put 250-400 parts of TPEG, 5-20 parts of acrylic acid and 100-350 parts of deionized water into a reactor, start stirring until TPEG is dissolved; add 1-10 parts of hydrogen peroxide to the mixture, stir for a period of time, add 0.1-5 parts of ferrous sulfate and continue stirring, and add dripping material A and dripping material B; aging the prepared mixture for 60 minutes, adding an appropriate amount of and; wherein, dripping material A is mixed by 20-50 parts of acrylic acid and 40-80 parts of deionized water; dripping material B is made of 0.5-5 parts of mercaptopropionic acid, 80-150 parts of deionized water and 0.1-2 parts of vitamin C is mixed. In this product, TPEG is used as a large monomer and acrylic acid is used as a small monomer. Mercaptopropionic acid is added as a chain transfer agent during the polymerization process, which can effectively control the molecular weight of the polymer and prevent the viscosity of the system caused by excessive molecular weight. If it is too high, it will affect the polymerization, and at the same time, an appropriate amount of carboxyl groups will be adsorbed on the surface of cement particles, providing an electrostatic repulsion effect and obtaining better popularity.

Description

A kind of high water reducing type water reducing agent and preparation method thereof

technical field

The invention relates to the technical field of water reducing agent processing, in particular to a high water reducing type water reducing agent and a preparation method thereof.

Background technique

Cement-based materials are the most commonly used building materials. Polycarboxylate superplasticizer is the most commonly used cement admixture. Because of its unique comb-shaped molecular structure, it can effectively reduce the Reduce water consumption and reduce water-cement ratio, so high-strength cement-based materials can be prepared. Therefore, the preparation of high-water-reducing polycarboxylate water-reducers, which can not only maintain the good flow properties of cement-based materials in the initial stage, but also have a high-performance water-reducer with ultra-long-term slump retention function, has a great market demand.

Contents of the invention

The purpose of the present invention is to provide a preparation method of an ultra-long slump-preserving water reducer to solve the technical problems raised in the above-mentioned background technology.

To achieve the above object, the present invention provides the following technical solutions:

A preparation method of a high water reducing type water reducing agent, comprising the following steps:

Step 1: Put 250-400 parts of TPEG, 5-20 parts of acrylic acid and 100-350 parts of deionized water into the reactor, start stirring until TPEG is completely dissolved;

Step 2: Add 1-10 parts of hydrogen peroxide to the mixture in step 1, add 0.1-5 parts of ferrous sulfate after stirring for a period of time, continue stirring, and add dripping material A and dripping material B at the same time;

Step 3: aging the mixture prepared in step 2 for 60 minutes, adding an appropriate amount to neutralize;

Wherein, dripping material A is formed by mixing 20-50 parts of acrylic acid and 40-80 parts of deionized water;

Dropping material B is formed by mixing 0.5-5 parts of mercaptopropionic acid, 80-150 parts of deionized water and 0.1-2 parts of vitamin C.

Preferably, in step 2, during the process of adding hydrogen peroxide, the reaction temperature is controlled below 30°C.

Preferably, in step 2, hydrogen peroxide is added, and ferrous sulfate is added after stirring for 4-6 minutes.

Preferably, in step 2, after adding ferrous sulfate and stirring for 4-6 minutes, add dripping material A and dripping material B at the same time.

Preferably, in step 2, the dripping material A is added dropwise at a uniform speed within 120 minutes.

Preferably, in step 2, the dripping material B is added dropwise at a constant speed within 120 minutes.

Preferably, in step 3, 100-300 parts of deionized water is added for aging the mixture.

Preferably, in step 3, the portion of caustic soda is 1-20 parts.

The invention also discloses a high water-reducing water-reducing agent, which is prepared by the above-mentioned preparation method.

Among them, the role of mercaptopropionic acid: it can be used as a chain transfer agent. During the polymer polymerization process, it can reduce the molecular weight to avoid excessive molecular weight, which will cause the system viscosity to be too high and affect the polymerization.

The present invention can take advantage of the low activation energy of ferrous sulfate, which is more likely to react. As the auxiliary reduction system of the H2O2-Vc system, the temperature of the redox initiation system composed of H2O2-Vc-FeSO4 rises quickly, and the polymerization reaction time can be shortened.

The role of sodium hydroxide: neutralize the acrylic acid in the system, avoiding the impact on cement-based materials due to excessive acidity.

The main function of the product: reduce the water consumption of cement-based materials

The main performance of the product: without affecting the construction of cement-based materials, it can reduce the unilateral water consumption and improve the workability of concrete; at the same time, the cement-based materials have greater fluidity.

Functional design requirements: meet the specific requirements of national standards GB8076-2008, TB/T3275-2018 and CRCC product certification implementation rules.

Compared with prior art, the beneficial effect of the present invention is:

This product uses TPEG as a large monomer and acrylic acid as a small monomer. During the polymerization process, mercaptopropionic acid is added as a chain transfer agent, which can effectively control the molecular weight of the polymer and prevent the polymerization from being affected by excessive viscosity of the system due to excessive molecular weight. At the same time, adding ferrous sulfate to the primer can effectively shorten the polymerization reaction time. The synthetic comb-shaped polymer is used in cement-based materials, which improves the large steric hindrance effect and effectively disperses the cement particles in the case of low water consumption; at the same time, the appropriate amount of carboxyl groups in the structure is adsorbed on the cement particles The surface provides an electrostatic repulsion effect, thus obtaining better popularity.

Detailed ways

The technical solutions of the present invention will be further described below in conjunction with specific examples, but the present invention is not limited to these examples.

Example

Process proportioning of the present invention is as follows:

TPEG 250-400 parts

Primer Deionized water (H2O) 100-350 parts

Hydrogen peroxide 1-10 parts

Acrylic acid (AA) 5-20 parts

Ferrous sulfate 0.1-5 parts

Acrylic acid 20-50 parts

Dropping material A deionized water 40-80 parts

Mercaptopropionic acid 0.5-5 parts

Dropping material B deionized water 80-150 parts

Vitamin C 0.1-2 parts

Hydrating deionized water 100-300 parts

Caustic soda 1-20 parts

The process conditions of the present invention are as follows:

Put TPEG, AA, and H2O into the reactor in turn, start stirring until TPEG is completely dissolved, control the temperature below 30°C, add initiator hydrogen peroxide, stir for 4-6 minutes, add ferrous sulfate and stir for 4-6 minutes while adding dropwise A and B solutions (A and B solutions need to be prepared in advance and stirred evenly). A solution is added dropwise at a constant speed in 120 minutes, and solution B is added dropwise at a constant speed in 120 minutes. After aging for 60 minutes, add appropriate amount of caustic soda to neutralize.

Get the finished product that above-mentioned process condition makes and do performance test as follows:

Test 1. Fluidity test of clean slurry: 300g of cement + 87g of water + 0.9g of the mother liquor of the developed water reducer, and the dosage of the mother liquor is 0.3%

Small test: Initial: 205*210

1 hour: 200*210

Test 2. Mortar fluidity test: 600g cement, 1200g machine-made sand, 270g water, 1% admixture

Small test: Initial: 370*370

1 hour: 230*230

Test 3, C30 concrete slump

Initial: 210mm

1 hour: 175mm

Test 4, 7 days strength: 32 MPa

To sum up, in this product, TPEG is used as a large monomer, acrylic acid is used as a small monomer, and mercaptopropionic acid is added as a chain transfer agent during the polymerization process, which can effectively control the molecular weight of the polymer and prevent the viscosity of the system caused by excessive molecular weight. Too high affects aggregation. At the same time, adding ferrous sulfate to the primer can effectively shorten the polymerization reaction time. The synthetic comb-shaped polymer is used in cement-based materials, which improves the large steric hindrance effect and effectively disperses the cement particles in the case of low water consumption; at the same time, the appropriate amount of carboxyl groups in the structure is adsorbed on the cement particles The surface provides an electrostatic repulsion effect, thus obtaining better popularity.

While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims (9)

1. A preparation method of high water-reducing type water-reducing agent, is characterized in that, comprises the following steps: Step 1: Put 250-400 parts of TPEG, 5-20 parts of acrylic acid and 100-350 parts of deionized water into the reactor, start stirring until TPEG is completely dissolved; Step 2: Add 1-10 parts of hydrogen peroxide to the mixture in step 1, add 0.1-5 parts of ferrous sulfate after stirring for a period of time, continue stirring, and add dripping material A and dripping material B at the same time; Step 3: aging the mixture prepared in step 2 for 60 minutes, adding an appropriate amount to neutralize; Wherein, dripping material A is formed by mixing 20-50 parts of acrylic acid and 40-80 parts of deionized water; Dropping material B is formed by mixing 0.5-5 parts of mercaptopropionic acid, 80-150 parts of deionized water and 0.1-2 parts of vitamin C. 2. The preparation method of a super-long slump-preserving water reducer according to claim 1, characterized in that: in step 2, during the process of adding hydrogen peroxide, the reaction temperature is controlled below 30°C. 3. The preparation method of a super-long slump-preserving water reducer according to claim 1, characterized in that: in step 2, hydrogen peroxide is added, and ferrous sulfate is added after stirring for 4-6 minutes. 4. The preparation method of a super-long slump-preserving water reducer according to claim 1 or 3, characterized in that: in step 2, add ferrous sulfate and stir for 4-6 minutes, then add dripping material A and Drop feed B. 5. The preparation method of a super-long slump-preserving water reducer according to claim 1 or 4, characterized in that: in step 2, the dripping material A is added dropwise at a uniform speed within 120 minutes. 6. The method for preparing an ultra-long slump-preserving water reducer according to claim 1 or 4, characterized in that: in step 2, the dripping material B is added dropwise at a constant speed within 120 minutes. 7. The preparation method of a super-long slump-preserving water reducer according to claim 1, characterized in that: in step 3, 100-300 parts of deionized water is added to the mixture after aging. 8. The preparation method of a super-long slump-preserving water reducer according to claim 1, characterized in that: in step 3, the amount of caustic soda is 1-20 parts. 9. A high-water-reducing water-reducing agent, characterized in that it is produced by the preparation method of any one of claims 1-8.