Preparation method of polycarboxylate superplasticizer and polycarboxylate superplasticizer

Abstract

The invention discloses a preparation method of a polycarboxylate superplasticizer and the polycarboxylate superplasticizer, belongs to the technical field of concrete admixtures, and solves the problems of insufficient applicability and low performance of the existing polycarboxylate superplasticizer. The method comprises the following steps: stirring and dissolving a polyether monomer, sequentially adding a dispersing agent and a pH regulator, and stirring and dissolving to obtain a main solution; the polyether monomer comprises ethylene glycol monovinyl polyoxyethylene ether. Adding the main solution into a reaction kettle, adding the catalytic solution into the main solution, and stirring for a certain time to obtain a base solution; and simultaneously dropwise adding the first reaction solution and the second reaction solution into the base solution. And after the first reaction solution and the second reaction solution are dropwise added, stirring for a certain time, adding aging water, and stirring to obtain the polycarboxylate superplasticizer mother liquor. The water reducing performance and adaptability of the polycarboxylate superplasticizer can be improved, the slump retaining capacity can also be improved, and the gradual loss of slump is reduced. And meanwhile, the energy consumption can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of concrete admixtures, and in particular to a preparation method of a polycarboxylate water reducer and the polycarboxylate water reducer. Background Art

[0002] Concrete is one of the most widely used building materials in engineering construction, and its development trend is to vigorously develop high-strength, high-performance and high-durability concrete. When preparing high-strength, high-performance and high-durability concrete, the application of high-performance admixtures is required, which can not only improve the strength and durability of concrete, but also significantly improve its performance.

[0003] At present, polycarboxylate water-reducing agents are widely used in concrete, which can form a stable and uniform cement particle dispersion system in concrete, so that concrete can show excellent fluidity at the same cement dosage, thereby reducing pores and structural defects caused by poor concrete flow. However, existing polycarboxylate water-reducing agents still have problems of insufficient applicability and low performance, especially in high-grade concrete. Summary of the invention

[0004] The embodiments of the present application provide a preparation method of a polycarboxylate water-reducing agent and a polycarboxylate water-reducing agent, thereby solving the problems of insufficient applicability and low performance of the existing polycarboxylate water-reducing agents.

[0005] In a first aspect, an embodiment of the present invention provides a method for preparing a polycarboxylate water-reducing agent, characterized in that it comprises:

[0006] After the polyether monomer is stirred and dissolved, a dispersant and a pH regulator are sequentially added and stirred and dissolved to obtain a main solution; the polyether monomer includes ethylene glycol monovinyl polyoxyethylene ether;

[0007] Add the main solution into a reaction kettle, add the catalytic solution into the main solution and stir for a certain period of time to obtain a base solution;

[0008] Simultaneously adding the first reaction solution and the second reaction solution to the base solution;

[0009] After the first reaction solution and the second reaction solution are added dropwise, the mixture is stirred for a certain period of time and then aged water is added and stirred to obtain a polycarboxylate water-reducing agent mother solution.

[0010] In combination with the first aspect, in a possible implementation manner, the mass ratio of the polyether monomer to water is 0.5 to 1:1.

[0011] In combination with the first aspect, in a possible implementation, the ethylene glycol monovinyl polyoxyethylene ether is selected from at least one of EPEG-3000, EPEG-4000, and EPEG-5000.

[0012] In combination with the first aspect, in a possible implementation manner, the mass ratio of the dispersant to the polyether monomer is 0.01 to 0.02:1;

[0013] The dispersant is at least one of sodium methacrylic acid sulfonate, sodium methacrylate and sodium methacrylate.

[0014] In combination with the first aspect, in a possible implementation, the mass ratio of the pH regulator to the polyether monomer is 0.002 to 0.005:1;

[0015] The pH regulator is at least one of sodium hydroxide and potassium hydroxide.

[0016] In combination with the first aspect, in a possible implementation, the catalytic solution includes an oxidant and a catalyst;

[0017] The mass ratio of the oxidant to the polyether monomer is 0.01-0.02:1, and the oxidant is at least one of hydrogen peroxide, ammonium persulfate, and sodium persulfate;

[0018] The mass ratio of the catalyst to the oxidant is 0.001-0.002:1, and the catalyst is at least one of ferrous sulfate and copper sulfate.

[0019] In combination with the first aspect, in a possible implementation, the first reaction solution includes a small monomer and water;

[0020] The mass ratio of the small monomer to the polyether monomer is 0.07-0.08:1, and the small monomer is at least one of acrylic acid and methacrylic acid;

[0021] The mass ratio of water in the first reaction solution to water in the main solution is 0.1-0.15:1.

[0022] In combination with the first aspect, in a possible implementation, the second reaction solution includes a chain transfer agent, a reducing agent and water;

[0023] The mass ratio of the chain transfer agent to the polyether monomer is 0.002-0.003:1, and the chain transfer agent is at least one of thioglycolic acid, mercaptopropionic acid, and mercaptoethanol;

[0024] The mass ratio of the reducing agent to the polyether monomer is 0.001-0.002:1, and the reducing agent is at least one of ascorbic acid, sodium hypophosphite, sodium sulfite, and sodium hydroxymethane sulfonate;

[0025] The mass ratio of water in the second reaction solution to water in the main solution is 0.1-0.35:1.

[0026] In combination with the first aspect, in a possible implementation manner, a mass ratio of the aged water to the water in the main solution is 0.1-0.2:1.

[0027] In a second aspect, an embodiment of the present invention provides a polycarboxylate water reducer, wherein the polycarboxylate water reducer is prepared by the above-mentioned method for preparing the polycarboxylate water reducer.

[0028] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0029] The embodiment of the present invention provides a method for preparing a polycarboxylate water-reducing agent, which comprises the steps of: stirring and dissolving a polyether monomer, and then sequentially adding a dispersant and a pH regulator to stir and dissolve to obtain a main solution. The polyether monomer comprises ethylene glycol monovinyl polyoxyethylene ether. The main solution is added into a reactor, and a catalytic solution is added into the main solution and stirred for a certain time to obtain a bottom solution. The first reaction solution and the second reaction solution are simultaneously added dropwise to the bottom solution. After the first reaction solution and the second reaction solution are added dropwise, stirring for a certain time and then adding aged water to stir to obtain a polycarboxylate water-reducing agent mother liquor. The present application uses ethylene glycol monovinyl polyoxyethylene ether as a monomer for synthesizing a water-reducing agent, and the double bond copolymerization activity of ethylene glycol monovinyl polyoxyethylene ether is high, and the reaction conversion rate is strong, which can not only improve the water-reducing performance and adaptability of the polycarboxylate water-reducing agent, but also improve the slump retention ability and reduce the time-dependent loss of slump. At the same time, the present application can react at room temperature, and there is no need to control the reaction temperature, thereby reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0031] Figure 1 This is a flowchart of the method for preparing the polycarboxylate water-reducing agent provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the embodiments of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the present invention. The terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to the specific circumstances.

[0034] like Figure 1 As shown, an embodiment of the present invention provides a method for preparing a polycarboxylate water-reducing agent, comprising the following steps:

[0035] Step 101: After the polyether monomer is stirred and dissolved, a dispersant and a pH regulator are added in sequence and stirred and dissolved to obtain a main solution. The polyether monomer includes ethylene glycol monovinyl polyoxyethylene ether. In practical applications, the polyether monomer is stirred and dissolved in a stirrer or stirred and dissolved in water. Generally, a dispersant and a pH regulator are added and stirred for 5 minutes to dissolve. Specifically, ethylene glycol monovinyl polyoxyethylene ether has high double bond copolymerization activity and a strong reaction conversion rate, which improves the water-reducing performance and adaptability of the polycarboxylic acid water-reducing agent and also improves the slump-retaining ability.

[0036] Step 102: Add the main solution into the reactor, add the catalytic solution into the main solution and stir for a certain period of time to obtain the base solution. The catalytic solution reacts quickly, so it should be added to the base solution as soon as possible after the preparation is completed.

[0037] Step 103: Start dripping the first reaction solution and the second reaction solution into the base solution at the same time. In practical applications, the first reaction solution and the second reaction solution are started to be dripped at the same time to ensure that the first reaction solution and the second reaction solution can react with the base solution at the same time, so that the reaction is more complete. Specifically, the catalytic solution is added to the main solution and stirred for 6 to 12 minutes before the first reaction solution and the second reaction solution are started to be dripped to ensure that the catalytic solution reacts more fully.

[0038] Step 104: After the first reaction solution and the second reaction solution are added dropwise, the mixture is stirred for a certain period of time and then aged water is added and stirred to obtain a polycarboxylate water-reducing agent mother solution. Specifically, the aged water can play a role in dilution and viscosity reduction.

[0039] The embodiment of the present invention provides a method for preparing a polycarboxylate water-reducing agent, which comprises the steps of: stirring and dissolving a polyether monomer, and then sequentially adding a dispersant and a pH regulator to stir and dissolve to obtain a main solution. The polyether monomer comprises ethylene glycol monovinyl polyoxyethylene ether. The main solution is added into a reactor, and a catalytic solution is added into the main solution and stirred for a certain time to obtain a bottom solution. The first reaction solution and the second reaction solution are simultaneously added dropwise to the bottom solution. After the first reaction solution and the second reaction solution are added dropwise, stirring for a certain time and then adding aged water to stir to obtain a polycarboxylate water-reducing agent mother liquor. The present application uses ethylene glycol monovinyl polyoxyethylene ether as a monomer for synthesizing a water-reducing agent, and the double bond copolymerization activity of ethylene glycol monovinyl polyoxyethylene ether is high, and the reaction conversion rate is strong, which can not only improve the water-reducing performance and adaptability of the polycarboxylate water-reducing agent, but also improve the slump retention ability and reduce the time-dependent loss of slump. At the same time, the present application can react at room temperature, and there is no need to control the reaction temperature, thereby reducing energy consumption.

[0040] In practical applications, the mass ratio of the polyether monomer to water is 0.5 to 1: 1. Preferably, the mass ratio of the polyether monomer to water is 1: 1 to improve the water reducing performance of the polycarboxylate water reducer.

[0041] Specifically, ethylene glycol monovinyl polyoxyethylene ether is selected from at least one of EPEG-3000, EPEG-4000 and EPEG-5000.

[0042] In practical applications, the mass ratio of the dispersant to the polyether monomer is 0.01 to 0.02: 1. The dispersant is at least one of sodium methacrylic acid sulfonate, sodium methacrylate, and sodium methacrylate.

[0043] In practical applications, the mass ratio of the pH regulator to the polyether monomer is 0.002-0.005:1. The pH regulator is at least one of sodium hydroxide and potassium hydroxide. The pH regulator is used to ensure that the final product is neutral.

[0044] Specifically, the catalytic solution includes an oxidant and a catalyst. The mass ratio of the oxidant to the polyether monomer is 0.01-0.02:1, and the oxidant is at least one of hydrogen peroxide, ammonium persulfate, and sodium persulfate. The mass ratio of the catalyst to the oxidant is 0.001-0.002:1, and the catalyst is at least one of ferrous sulfate and copper sulfate.

[0045] In practical applications, the first reaction solution includes a small monomer and water. The mass ratio of the small monomer to the polyether monomer is 0.07-0.08:1, and the small monomer is at least one of acrylic acid and methacrylic acid. The mass ratio of water in the first reaction solution to water in the main solution is 0.1-0.15:1.

[0046] In practical applications, the second reaction solution includes a chain transfer agent, a reducing agent and water. The mass ratio of the chain transfer agent to the polyether monomer is 0.002-0.003:1, and the chain transfer agent is at least one of thioglycolic acid, mercaptopropionic acid, and mercaptoethanol. The mass ratio of the reducing agent to the polyether monomer is 0.001-0.002:1, and the reducing agent is at least one of ascorbic acid, sodium hypophosphite, sodium sulfite, and sodium hydroxymethyl sulfonate. The mass ratio of water in the second reaction solution to water in the main solution is 0.1-0.35:1. The reducing agent used in this application is a high molecular polymer with strong reducing properties and better stability, which makes the polycarboxylic acid water reducer more stable during the polymerization reaction, and makes the synthesized polycarboxylic acid water reducer have stronger water reduction performance and slump retention performance. Specifically, the water reduction performance increases by about 5%, and the slump retention performance can be increased by 2% to 5%.

[0047] Specifically, the mass ratio of the aged water to the water in the main solution is 0.1-0.2:1.

[0048] An embodiment of the present invention provides a polycarboxylate water reducer, which is prepared by the above-mentioned method for preparing the polycarboxylate water reducer.

[0049] The present invention is further described in detail below through specific examples and comparative examples.

[0050] The experimental methods in the following examples are conventional methods unless otherwise specified. The experimental materials and reagents used in the following examples are commercially available unless otherwise specified. The quantitative tests in the following examples were repeated three times, and the data are the average or average ± standard deviation of the three repeated experiments.

[0051] Embodiment 1:

[0052] Add 798g of water to a beaker, then add 738g of ethylene glycol monovinyl polyoxyethylene ether (EPEG-3000) and stir to dissolve, then add 10g of sodium methyl propylene sulfonate and 3g of sodium hydroxide in sequence and stir until completely dissolved to obtain a main solution;

[0053] Add the main solution into the reactor and turn on the agitator to stir;

[0054] Add 10g hydrogen peroxide and 16mg copper sulfate into a beaker and completely dissolve to obtain a catalytic solution, and inject the catalytic solution into the reactor;

[0055] 110 g of water and 56 g of acrylic acid were added to a beaker and stirred to obtain a first reaction solution. 160 g of water, 2 g of mercaptopropionic acid and 1.2 g of ascorbic acid were added to a beaker and stirred to obtain a second reaction solution.

[0056] Under normal temperature conditions, the catalytic solution was injected into the reactor and stirred for 10 minutes, and then the first reaction solution and the second reaction solution were added dropwise at the same time. The first reaction solution was added dropwise for 60 minutes, and the second reaction solution was added dropwise for 70 minutes.

[0057] After the first reaction solution and the second reaction solution were added dropwise, stirring was continued for 60 minutes, and then 110 g of aged water was added and stirred for 10 minutes to obtain a polycarboxylate water-reducing agent mother solution.

[0058] Embodiment 2:

[0059] Add 798g of water to a beaker, then add 738g of ethylene glycol monovinyl polyoxyethylene ether (EPEG-3000) and stir to dissolve, then add 10g of sodium methacrylate and 3g of sodium hydroxide in sequence and stir until completely dissolved to obtain a main solution;

[0060] Add the main solution into the reactor and turn on the agitator to stir;

[0061] Add 10g hydrogen peroxide and 16mg copper sulfate into a beaker and completely dissolve to obtain a catalytic solution, and inject the catalytic solution into the reactor;

[0062] 110 g of water and 56 g of acrylic acid were added to a beaker and stirred to obtain a first reaction solution. 160 g of water, 2 g of mercaptopropionic acid and 1.2 g of sodium hydroxymethanesulfonate were added to a beaker and stirred to obtain a second reaction solution.

[0063] Under normal temperature conditions, the catalytic solution was injected into the reactor and stirred for 10 minutes, and then the first reaction solution and the second reaction solution were added dropwise at the same time. The first reaction solution was added dropwise for 60 minutes, and the second reaction solution was added dropwise for 70 minutes.

[0064] After the first reaction solution and the second reaction solution were added dropwise, stirring was continued for 60 minutes, and then 110 g of aged water was added and stirred for 10 minutes to obtain a polycarboxylate water-reducing agent mother solution.

[0065] Comparative Example 1:

[0066] The difference from Example 1 is that the dispersant sodium methacrylate sulfonate is not added in the synthesis step.

[0067] Comparative Example 2:

[0068] The polycarboxylate water reducer is a commercially available FJW-1 standard concrete water reducer.

[0069] Comparative Example 3:

[0070] The polycarboxylate water reducer was a commercially available TC-PCA1066 standard concrete water reducer.

[0071] (1) The polycarboxylate water-reducing agents in Example 1, Example 2, Comparative Example 1, Comparative Example 2 and Comparative Example 3 were subjected to an admixture performance test. The water reduction rate of cement mortar was determined using Fuping Ecological P·O42.5 cement. The admixture performance test was conducted in accordance with GB / T8077-2023 "Test Method for Homogeneity of Concrete Admixtures". The performance test results are shown in Table 1:

[0072] Serial number category Dosage / % Fluidity / mm Water reduction rate / % 1 Example 1 1.0 183 34.1 2 Example 2 1.0 180 35.6 3 Comparative Example 1 1.0 182 30.7 4 Comparative Example 2 1.0 181 31.7 5 Comparative Example 3 1.0 181 30.2

[0073] Table 1. Test results of water reduction rate of cement mortar

[0074] As shown in Table 1, the polycarboxylic acid water-reducing agents prepared in Example 1 and Example 2 have high water-reducing rates and higher water-reducing effects than commercially available water-reducing agents, and have good dispersibility and water-reducing properties.

[0075] (2) The polycarboxylate water-reducing agents in Example 2, Comparative Example 2 and Comparative Example 3 were tested for concrete performance. Jidong P·O52.5 cement was used to measure the performance of cement concrete. The concrete mix ratio design for the test was referenced. The concrete mix ratio design is shown in Table 2:

[0076]

[0077] Table 2. Concrete mix ratio

[0078] The dosage of each component in the mix design was controlled to remain unchanged, and the dosage of admixtures was adjusted to make the concrete reach the same initial slump (210±10). The test results are shown in Tables 3 and 4.

[0079]

[0080] Table 3. Test results of concrete slump and time loss

[0081]

[0082] Table 4 Concrete compressive strength test results

[0083] It can be seen from the above table that the polycarboxylate water-reducing agent prepared by the preparation method of the present application is superior to commercially available water-reducing agents in terms of water reduction rate, slump retention performance and improvement of concrete strength.

[0084] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments.

[0085] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A method for preparing a polycarboxylate water-reducing agent, characterized in that: include: After the polyether monomer is stirred and dissolved, a dispersant and a pH regulator are sequentially added and stirred and dissolved to obtain a main solution; the polyether monomer includes ethylene glycol monovinyl polyoxyethylene ether; Add the main solution into a reaction kettle, add the catalytic solution into the main solution and stir for a certain period of time to obtain a base solution; Simultaneously adding the first reaction solution and the second reaction solution to the base solution; After the first reaction solution and the second reaction solution are added dropwise, the mixture is stirred for a certain period of time and then aged water is added and stirred to obtain a polycarboxylate water-reducing agent mother solution.

2. The method for preparing a polycarboxylate water-reducing agent according to claim 1, characterized in that: The mass ratio of the polyether monomer to water is 0.5 to 1:

1.

3. The method for preparing a polycarboxylate water-reducing agent according to claim 1, characterized in that: The ethylene glycol monovinyl polyoxyethylene ether is selected from at least one of EPEG-3000, EPEG-4000 and EPEG-5000.

4. The method for preparing a polycarboxylate water-reducing agent according to claim 1, characterized in that: The mass ratio of the dispersant to the polyether monomer is 0.01 to 0.02:1; The dispersant is at least one of sodium methacrylic acid sulfonate, sodium methacrylate and sodium methacrylate.

5. The method for preparing a polycarboxylate water-reducing agent according to claim 1, characterized in that: The mass ratio of the pH regulator to the polyether monomer is 0.002-0.005:1; The pH regulator is at least one of sodium hydroxide and potassium hydroxide.

6. The method for preparing a polycarboxylate water-reducing agent according to claim 1, characterized in that: The catalytic solution includes an oxidant and a catalyst; The mass ratio of the oxidant to the polyether monomer is 0.01-0.02:1, and the oxidant is at least one of hydrogen peroxide, ammonium persulfate, and sodium persulfate; The mass ratio of the catalyst to the oxidant is 0.001-0.002:1, and the catalyst is at least one of ferrous sulfate and copper sulfate.

7. The method for preparing a polycarboxylate water-reducing agent according to claim 1, characterized in that: The first reaction solution includes a small monomer and water; The mass ratio of the small monomer to the polyether monomer is 0.07-0.08:1, and the small monomer is at least one of acrylic acid and methacrylic acid; The mass ratio of water in the first reaction solution to water in the main solution is 0.1-0.15:

1.

8. The method for preparing a polycarboxylate water-reducing agent according to claim 1, characterized in that: The second reaction solution comprises a chain transfer agent, a reducing agent and water; The mass ratio of the chain transfer agent to the polyether monomer is 0.002-0.003:1, and the chain transfer agent is at least one of thioglycolic acid, mercaptopropionic acid, and mercaptoethanol; The mass ratio of the reducing agent to the polyether monomer is 0.001-0.002:1, and the reducing agent is at least one of ascorbic acid, sodium hypophosphite, sodium sulfite, and sodium hydroxymethane sulfonate; The mass ratio of water in the second reaction solution to water in the main solution is 0.1-0.35:

1.

9. The method for preparing a polycarboxylate water-reducing agent according to claim 1, characterized in that: The mass ratio of the aged water to the water in the main solution is 0.1-0.2:

1.

10. A polycarboxylate water reducer, characterized in that: The polycarboxylate water reducer is prepared by the preparation method of the polycarboxylate water reducer according to any one of claims 1 to 9.

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