CN107200817B - A kind of preparation method of stable concrete slump control agent - Google Patents

Abstract

The invention discloses a preparation method of a stable concrete slump control agent. The ester group, benzene ring and sulfonic acid group structure are introduced into the molecular structure through the esterification product of unsaturated carboxylic acid and compound A. The sulfonic acid group with water-reducing effect and the benzene ring with steric hindrance effect are introduced, so that the product has a high initial water-reducing rate, and the introduced ester structure will gradually hydrolyze under the alkaline condition of concrete, and Since the number of groups with dispersing effect in the molecular structure of the product before and after the hydrolysis of the ester group does not change much, the problem of hysteresis amplification of the concrete slump caused by the rapid hydrolysis of the ester group will not occur, nor will it occur due to the excessive hydrolysis of the ester group. The problem is that the slump loss of concrete is too fast, so it is not easily affected by changes in the use conditions during use, and the stable control of the slump of concrete can be achieved.

Description

A kind of preparation method of stable concrete slump control agent

technical field

The invention belongs to the technical field of building materials, and particularly relates to a preparation method of a stable concrete slump control agent.

Background technique

With the rapid development of concrete technology in the direction of high strength, green and high performance, the water reducing agent as an important part of concrete has also been put forward higher and more comprehensive requirements. In the past, traditional concrete water-reducing agents, such as the first-generation lignin and the second-generation naphthalene sulfonate series, sulfonated melamine series, sulfamic acid series, aliphatic series and other water reducing agents, due to the large dosage, The water reduction rate is not high enough, the enhancement effect is not very significant, and the loss of concrete slump is large, which has gradually failed to meet the development of modern concrete technology and modern concrete construction methods. Especially in the production process, harmful chemical substances such as industrial naphthalene, concentrated sulfuric acid, formaldehyde, liquid caustic soda and phenol are inevitably used, which will inevitably cause certain pollution to the environment, and have disadvantages such as problems that are not conducive to sustainable development, which partially restricts its use. Further promotion and application.

Due to its excellent performance, energy saving and environmental protection, and good concrete durability, polycarboxylate superplasticizers have been used in high-speed rail, hydropower, nuclear power and other national key projects since 2006. However, with the shortage of resources and the improvement of concrete performance requirements, polycarboxylate superplasticizers often have problems that the slump retention effect is insufficient in the process of promotion and application, and the slump retention effect is easily affected by factors such as temperature. And the stable concrete slump control agent that is not sensitive to the use conditions is of great significance.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the defects of the prior art and provide a preparation method of a stable concrete slump control agent.

The technical scheme of the present invention is as follows:

A preparation method of a stable concrete slump control agent, comprising the following steps:

(1) Mix unsaturated carboxylic acid, compound A and polymerization inhibitor, under nitrogen protection, heat up to 40～60 ℃, add catalyst again, heat up to 100～140 ℃, heat preservation reaction 0.5～3h, use vacuum during this period Or the method of logical nitrogen with water removes water, and after the reaction finishes, it is lowered to room temperature to obtain the first mixture containing esterified product and unreacted unsaturated carboxylic acid, and the mol ratio of unsaturated carboxylic acid and compound A is 1.5～6: 1. The consumption of catalyst is 0.5%～5.0% of the total mass of unsaturated carboxylic acid and compound A, and the consumption of polymerization inhibitor is 0.5%～5.0% of the total mass of unsaturated carboxylic acid and compound A, and the structural formula of compound A is as follows:

wherein R ₁ is an alkyl group of 1 to 4 carbons or none, and R2 is an alkyl group of 1 to 4 carbons or none;

(2) mixing the first mixture prepared in step (1) and 4-hydroxybutyl vinyl polyoxyethylene ether with a molecular weight of 600-5000 in a mass ratio of 1:4-30, and adding water to dissolve it, to obtain a comonomer mixture solution;

(3) drop the above-mentioned comonomer mixture solution, initiator aqueous solution and molecular weight regulator aqueous solution into water for reaction, the reaction temperature is 10～40°C, the dropping time is 0.2～6.0h, and the temperature is kept for 0～3.0 hours after the dropping is completed. h, to obtain a copolymerization product; the total amount of water used in this step and step (2) makes the mass concentration of the copolymerization product 20-80%, and the consumption of the initiator is 0.5-3.0% of the total mass of the solute in the comonomer mixture solution %, the dosage of the molecular weight regulator is 0.2-3.0% of the total mass of the solute in the comonomer mixture solution;

(4) Adjusting the pH of the copolymerized product obtained in step (3) to 5-7 with alkali to obtain the stable concrete slump control agent.

In a preferred embodiment of the present invention, the step (1) is as follows: mixing the unsaturated carboxylic acid, compound A, and a polymerization inhibitor, under nitrogen protection, heating up to 50-60° C., then adding a catalyst, and heating to 50-60° C. 105～130 ℃, heat preservation reaction for 1～3h, during which water is removed by vacuuming or passing nitrogen with water, after the reaction is completed, it is lowered to room temperature to obtain the first mixture containing the esterified product and the unreacted unsaturated carboxylic acid, The molar ratio of unsaturated carboxylic acid and compound A is 1.5～5:1, the dosage of catalyst is 0.5%～4.0% of the total mass of unsaturated carboxylic acid and compound A, and the dosage of polymerization inhibitor is the total amount of unsaturated carboxylic acid and compound A. 0.5% to 4.0% of the mass.

In a preferred embodiment of the present invention, the step (2) is as follows: the first mixture obtained in the step (1), 4-hydroxybutyl vinyl polyoxyethylene ether with a molecular weight of 600-5000, in a ratio of 1: The mixture is mixed in a mass ratio of 5 to 20, and water is added to dissolve it to obtain a comonomer mixture solution.

In a preferred embodiment of the present invention, the step (3) is as follows: dropping the above-mentioned comonomer mixture solution, the initiator aqueous solution and the molecular weight regulator aqueous solution into water for reaction, the reaction temperature is 10-30 °C, and the dropwise addition The time is 0.2-5.0h, and after the dropping is completed, the temperature is kept for 0-3.0h to obtain a copolymerization product; the total amount of water used in this step and step (2) makes the mass concentration of the copolymerization product 20-70%, and the amount of the initiator It is 0.5-2.0% of the total mass of the solute in the comonomer mixture solution, and the amount of the molecular weight regulator is 0.2-2.0% of the total mass of the solute in the comonomer mixture solution.

Further preferably, the unsaturated carboxylic acid is at least one of acrylic acid and methacrylic acid.

Further preferably, the catalyst is at least one of ethylsulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid and 98% concentrated sulfuric acid.

Further preferably, the polymerization inhibitor is at least one of hydroquinone, phenothiazine and diphenylamine.

Further preferably, the initiator is a water-soluble redox initiation system or a water-soluble azo initiator.

Further preferably, the molecular weight regulator is at least one of thioglycolic acid, mercaptopropionic acid, mercaptoethanol, isopropanol, sodium hypophosphite, trisodium phosphate, sodium formate, sodium acetate and dodecanethiol.

Beneficial effects of the present invention:

1. The present invention introduces an ester group, a benzene ring and a sulfonic acid group structure into the molecular structure through the esterification product of unsaturated carboxylic acid and compound A. Initially, due to the introduction of a sulfonic acid group with a water-reducing effect and a space The benzene ring of the steric hindrance effect makes the product of the product have a high initial water reduction rate.

2. When the stable concrete slump control agent prepared by the preparation method of the present invention is used in concrete, under the alkaline environment of concrete, the ester bond in the molecular structure will be gradually hydrolyzed to release the carboxyl group with water-reducing effect, so as to realize Excellent slump retention effect, and because the number of groups with dispersing effect in the molecular structure of the product before and after hydrolysis of the ester group does not change much, the problem of hysteresis and amplification of concrete slump caused by the rapid hydrolysis of the ester group will not occur. There is also no problem of too fast loss of concrete slump due to too slow hydrolysis of ester groups, so it is not easily affected by changes in use conditions during use, and stable control of concrete slump can be achieved.

Detailed ways

The technical solutions of the present invention will be further illustrated and described below through specific embodiments.

Example 1

(1) Mix 240.00g of acrylic acid, 200.00g of p-hydroxybenzenesulfonic acid and 6.50g of phenothiazine, under nitrogen protection, heat up to 60°C, add 8.23g of p-toluenesulfonic acid, heat up to 110°C, keep the temperature for 2h, During the period, water is removed by means of vacuuming or nitrogen and water, and the reaction is lowered to room temperature to obtain the first mixture containing the esterified product and unreacted acrylic acid;

(2) Mix 20.00 g of the first mixture prepared in step (1) and 185.00 g of 4-hydroxybutyl vinyl polyoxyethylene ether with a molecular weight of 2400, and add 120.00 g of water to dissolve it to obtain a comonomer mixture solution;

(3) Mix the above comonomer mixture solution with hydrogen peroxide solution (wherein, hydrogen peroxide 1.20g, water 20.00g), ascorbic acid aqueous solution (wherein, ascorbic acid 0.40g, water 20.00g), ferrous sulfate solution (wherein, ferrous sulfate 0.40g g, water 10.00g) and thioglycolic acid aqueous solution (wherein, thioglycolic acid 1.20g, water 20.00g) were dropped into 60.00g of water for reaction, the reaction temperature was 30 ° C, the dropwise addition time was 2.0h, and the temperature was kept for 0.5h after the dropwise addition was completed. , the copolymerization product is obtained;

(4) Adjusting the pH of the copolymerized product obtained in step (3) to 5-7 with alkali to obtain the stable concrete slump control agent KZJ-1.

Example 2

(1) Mix 247.00g methacrylic acid, 200.00g p-methylolbenzenesulfonic acid, 5.60g hydroquinone and 2.00g phenothiazine, under nitrogen protection, heat up to 50°C, add 8.20g mass fraction of 98% concentrated sulfuric acid was heated to 115°C, and the reaction was kept for 3 hours, during which water was removed by vacuuming or nitrogen and water, and after the reaction was completed, it was lowered to room temperature to obtain the first product containing the esterified product and unreacted methacrylic acid. a mixture;

(2) Mix 20.00 g of the first mixture prepared in step (1) and 260.00 g of 4-hydroxybutyl vinyl polyoxyethylene ether with a molecular weight of 2400, and add 150.00 g of water to dissolve it to obtain a comonomer mixture solution;

(3) with the above-mentioned comonomer mixture solution and hydrogen peroxide solution (wherein, hydrogen peroxide 1.10g, water 20.00g), hanging white block aqueous solution (wherein, hanging white block 0.70g, water 20.00g), ferrous sulfate solution (wherein, Ferrous sulfate 0.50g, water 10.00g) and mercaptopropionic acid aqueous solution (among them, mercaptopropionic acid 1.50g, water 20.00g) were dropped into 60.00g of water for reaction, the reaction temperature was 20°C, the dropwise addition time was 1.0h, and the dropwise addition time was 1.0 h. After adding, keep the temperature for 1h to obtain a copolymer product;

(4) Adjusting the pH of the copolymerized product obtained in step (3) to 5-7 with alkali, to obtain the stable concrete slump control agent KZJ-2.

Example 3

(1) Mix 156g of acrylic acid, 86g of methacrylic acid, 200.00g of p-hydroxyethylbenzenesulfonic acid, and 4.20g of hydroquinone, under nitrogen protection, heat up to 60°C, add 6.30g of ethylsulfonic acid, and heat up to 110 ° C, heat preservation reaction for 2 hours, during which water is removed by vacuuming or passing nitrogen and water, and after the reaction is completed, it is lowered to room temperature to obtain the first mixture containing the esterified product and unreacted acrylic acid and methacrylic acid;

(2) Mix 20.00 g of the first mixture obtained in step (1) and 233.00 g of 4-hydroxybutyl vinyl polyoxyethylene ether with a molecular weight of 2400, and add 150.00 g of water to dissolve it to obtain a comonomer mixture solution;

(3) Mix the above comonomer mixture solution with hydrogen peroxide solution (wherein, hydrogen peroxide 1.30g, water 20.00g), ascorbic acid aqueous solution (wherein, ascorbic acid 0.30g, water 20.00g), ferrous sulfate solution (wherein, ferrous sulfate 0.50g g, water 10.00g) and trisodium phosphate aqueous solution (wherein, trisodium phosphate 2.00g, water 20.00g) were dropped into 60.00g of water for reaction, the reaction temperature was 10°C, the dropping time was 1.5h, and the temperature was kept warm after the dropwise addition was completed. 1h, the copolymerization product was obtained;

(4) Adjusting the pH of the copolymerized product obtained in step (3) to 5-7 with alkali to obtain the stable concrete slump control agent KZJ-3.

Example 4

(1) Mix 177.00g of acrylic acid, 200.00g of 4-hydroxyphenylmethanesulfonic acid and 6.60g of diphenylamine, under nitrogen protection, heat up to 60°C, add 5.50g of concentrated sulfuric acid with a mass fraction of 98%, and heat up to 105°C , insulation reaction 3h, removes water with the method of vacuuming or passing nitrogen and carrying water during the period, after the reaction is finished, it is lowered to room temperature to obtain the first mixture containing the esterified product and unreacted acrylic acid;

(2) 20.00 g of the first mixture obtained in step (1) and 244.00 g of 4-hydroxybutyl vinyl polyoxyethylene ether with a molecular weight of 3000 were mixed, and 150.00 g of water was added to dissolve it to obtain a comonomer mixture solution;

(3) with above-mentioned comonomer mixture solution and hydrogen peroxide aqueous solution (wherein, hydrogen peroxide 2.00g, water 20.00g), hanging white block aqueous solution (wherein, hanging white block 1.20g, water 20.00g), ferrous sulfate solution (wherein, Ferrous sulfate 0.70g, water 10.00g), isopropanol aqueous solution (among which, isopropanol 1.50g, water 20.00g) were dropped into 60.00g water for reaction, the reaction temperature was 25 ℃, the dropping time was 0.5h, and the dropwise addition time was 0.5h. After adding, keep the temperature for 1.5h to obtain a copolymer product;

(4) Adjusting the pH of the copolymerized product obtained in step (3) to 5-7 with alkali to obtain the stable concrete slump control agent KZJ-4.

Example 5

(1) Mix 140.00g of acrylic acid, 87.00g of p-hydroxybenzenesulfonic acid, 113g of p-hydroxymethylbenzenesulfonic acid, and 3.40g of hydroquinone, under nitrogen protection, heat up to 50°C, add 4.60g of benzenesulfonic acid, The temperature is raised to 120°C, and the reaction is kept for 2 hours, during which water is removed by means of vacuuming or nitrogen and water, and after the reaction is completed, the temperature is lowered to room temperature to obtain the first mixture containing the esterified product and unreacted acrylic acid;

(2) Mix 20.00 g of the first mixture prepared in step (1) and 220.00 g of 4-hydroxybutyl vinyl polyoxyethylene ether with a molecular weight of 3000, and add 150.00 g of water to dissolve it to obtain a comonomer mixture solution;

(3) Mix the above comonomer mixture solution with azodiisobutylamidine hydrochloride aqueous solution (wherein azodiisobutylamidine hydrochloride 1.80g, water 30.00g), dodecanethiol aqueous solution (wherein, Dodecanethiol 2.30g, water 30.00g) was dropped into 70.00g of water for reaction, the reaction temperature was 30°C, the dropwise addition time was 3.0h, and the temperature was kept for 1.0h after the dropwise addition to obtain a copolymerization product;

(4) Adjusting the pH of the copolymerized product obtained in step (3) to 5-7 with alkali to obtain the stable concrete slump control agent KZJ-5.

For the stable concrete slump control agents (KZJ-1, KZJ-2, KZJ-3, KZJ-4 and KZJ-5) prepared in Examples 1 to 5 and commercially available slump-preserving polycarboxylate Acid water reducing agent (PCE) is used to compare the performance of concrete with different materials and different temperatures. Minfu cement (P.O42.5R) is used, and the concrete mix ratio is: cement 280kg/m ³ , fly ash 80kg/m ³ , sand 770kg/m ³ , stone 1040kg/m ³ , water 160kg/m ³ , respectively. The properties of concrete mixed with KZJ-1, KZJ-2, KZJ-3, KZJ-4, KZJ-5 and PCE were tested under the conditions of sand and mud content of 1%, 5% and temperature of 5°C and 35°C, respectively. The slump loss control ability of different admixtures, by adjusting the dosage, the initial expansion of concrete is within the range of 550±10mm, and the slump (TL) and expansion (TK) of each admixture for 1h, 2h and 3h are tested. , the results are shown in Table 1 and Table 2:

Table 1 Concrete properties of admixtures with different sand and mud contents

Table 2 Concrete properties of each admixture under different temperature conditions

It can be seen from the above results that the initial water-reducing rate of the commercially available slump-preserving polycarboxylate water-reducing agent (PCE) is lower than that of the synthetic examples of the present patent under different experimental conditions. When changing, the slump loss of the commercially available slump-preserving polycarboxylate superplasticizer (PCE) is larger than that of the examples synthesized in this patent, that is, its ability to control the slump of concrete is better when the experimental conditions change. The synthetic examples of this patent are weak.

Those of ordinary skill in the art know that when the technical parameters of the present invention and the raw material components are changed within the following scope, the same or similar technical effects as the above-described embodiments can still be obtained, which still belongs to the protection scope of the present invention:

A preparation method of a stable concrete slump control agent, comprising the following steps:

(1) Mix unsaturated carboxylic acid, compound A and polymerization inhibitor, under nitrogen protection, heat up to 40～60 ℃, add catalyst again, heat up to 100～140 ℃, heat preservation reaction 0.5～3h, use vacuum during this period Or the method of logical nitrogen with water removes water, and after the reaction finishes, it is lowered to room temperature to obtain the first mixture containing esterified product and unreacted unsaturated carboxylic acid, and the mol ratio of unsaturated carboxylic acid and compound A is 1.5～6: 1. The consumption of catalyst is 0.5%～5.0% of the total mass of unsaturated carboxylic acid and compound A, and the consumption of polymerization inhibitor is 0.5%～5.0% of the total mass of unsaturated carboxylic acid and compound A, and the structural formula of compound A is as follows:

wherein R ₁ is an alkyl group of 1 to 4 carbons or none, and R ₂ is an alkyl group of 1 to 4 carbons or none;

(2) mixing the first mixture prepared in step (1) and 4-hydroxybutyl vinyl polyoxyethylene ether with a molecular weight of 600-5000 in a mass ratio of 1:4-30, and adding water to dissolve it, to obtain a comonomer mixture solution;

(3) drop the above-mentioned comonomer mixture solution, initiator aqueous solution and molecular weight regulator aqueous solution into water for reaction, the reaction temperature is 10～40°C, the dropping time is 0.2～6.0h, and the temperature is kept for 0～3.0 hours after the dropping is completed. h, to obtain a copolymerization product; the total amount of water used in this step and step (2) makes the mass concentration of the copolymerization product 20-80%, and the consumption of the initiator is 0.5-3.0% of the total mass of the solute in the comonomer mixture solution %, the dosage of the molecular weight regulator is 0.2-3.0% of the total mass of the solute in the comonomer mixture solution;

(4) Adjusting the pH of the copolymerized product obtained in step (3) to 5-7 with alkali to obtain the stable concrete slump control agent.

The unsaturated carboxylic acid is at least one of acrylic acid and methacrylic acid. The catalyst is at least one of ethylsulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid and 98% concentrated sulfuric acid. The polymerization inhibitor is at least one of hydroquinone, phenothiazine and diphenylamine. The initiator is a water-soluble redox initiator system or a water-soluble azo initiator. The molecular weight regulator is at least one of thioglycolic acid, mercaptopropionic acid, mercaptoethanol, isopropanol, sodium hypophosphite, trisodium phosphate, sodium formate, sodium acetate and dodecanethiol.

The above are only the preferred embodiments of the present invention, so the scope of implementation of the present invention cannot be limited accordingly, that is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the description should still be covered by the present invention. In the range.

Claims (8)

1. a preparation method of stable concrete slump control agent, is characterized in that: comprise the steps: (1) Mix unsaturated carboxylic acid, compound A and polymerization inhibitor, under nitrogen protection, heat up to 40～60 ℃, add catalyst again, heat up to 100～140 ℃, heat preservation reaction 0.5～3h, use vacuum during this period Or the method of logical nitrogen with water removes water, and after the reaction finishes, it is lowered to room temperature to obtain the first mixture containing esterified product and unreacted unsaturated carboxylic acid, and the mol ratio of unsaturated carboxylic acid and compound A is 1.5～6: 1. The consumption of catalyst is 0.5%～5.0% of the total mass of unsaturated carboxylic acid and compound A, and the consumption of polymerization inhibitor is 0.5%～5.0% of the total mass of unsaturated carboxylic acid and compound A, and the structural formula of compound A is as follows: wherein R ₁ is an alkyl group of 1 to 4 carbons or none, and R2 is an alkyl group of 1 to 4 carbons or none; the above-mentioned unsaturated carboxylic acid is at least one of acrylic acid and methacrylic acid; (2) mixing the first mixture prepared in step (1) and 4-hydroxybutyl vinyl polyoxyethylene ether with a molecular weight of 600-5000 in a mass ratio of 1:4-30, and adding water to dissolve it, to obtain a comonomer mixture solution; (3) drop the above-mentioned comonomer mixture solution, initiator aqueous solution and molecular weight regulator aqueous solution into water for reaction, the reaction temperature is 10～40°C, the dropping time is 0.2～6.0h, and the temperature is kept for 0～3.0 hours after the dropping is completed. h, to obtain a copolymerization product; the total amount of water used in this step and step (2) makes the mass concentration of the copolymerization product 20-80%, and the consumption of the initiator is 0.5-3.0% of the total mass of the solute in the comonomer mixture solution %, the dosage of the molecular weight regulator is 0.2-3.0% of the total mass of the solute in the comonomer mixture solution; (4) Adjusting the pH of the copolymerized product obtained in step (3) to 5-7 with alkali to obtain the stable concrete slump control agent. 2. preparation method as claimed in claim 1 is characterized in that: described step (1) is: mix unsaturated carboxylic acid, compound A, polymerization inhibitor, under nitrogen protection, be warmed up to 50～60 ℃, Then add the catalyst, heat up to 105～130℃, keep the reaction for 1～3h, remove the water by vacuuming or pass nitrogen and bring water during the period, after the reaction is finished, it is lowered to room temperature to obtain the esterified product and unreacted unsaturated carboxylate The first mixture of acids, the molar ratio of unsaturated carboxylic acid and compound A is 1.5 to 5:1, the amount of catalyst used is 0.5% to 4.0% of the total mass of unsaturated carboxylic acid and compound A, and the amount of polymerization inhibitor is unsaturated 0.5% to 4.0% of the total mass of carboxylic acid and compound A. 3. The preparation method according to claim 1, characterized in that: the step (2) is: the first mixture obtained in the step (1), the 4-hydroxybutyl vinyl polyoxyethylene having a molecular weight of 600-5000 The vinyl ethers are mixed in a mass ratio of 1:5 to 20, and water is added to dissolve them to obtain a comonomer mixture solution. 4. preparation method as claimed in claim 1 is characterized in that: described step (3) is: the above-mentioned comonomer mixture solution and initiator aqueous solution and molecular weight regulator aqueous solution are dropped into water and react, and reaction temperature is 10 ～30°C, the dropping time is 0.2～5.0h, and the temperature is kept for 0～3.0h after the dropping is completed to obtain a copolymerization product; the total amount of water used in this step and step (2) makes the mass concentration of the copolymerization product 20～70 %, the dosage of the initiator is 0.5-2.0% of the total mass of the solute in the comonomer mixture solution, and the dosage of the molecular weight regulator is 0.2-2.0% of the total mass of the solute in the comonomer mixture solution. 5. The preparation method according to any one of claims 1 to 4, wherein the catalyst is at least one of ethylsulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid and 98% of the concentrated sulfuric acid kind. 6 . The preparation method according to claim 1 , wherein the polymerization inhibitor is at least one of hydroquinone, phenothiazine and diphenylamine. 7 . 7. The preparation method according to any one of claims 1 to 4, wherein the initiator is a water-soluble redox initiation system or a water-soluble azo initiator. 8. The preparation method according to any one of claims 1 to 4, wherein the molecular weight regulator is thioglycolic acid, mercaptopropionic acid, mercaptoethanol, isopropanol, sodium hypophosphite, trisodium phosphate , at least one of sodium formate, sodium acetate and dodecanethiol.