Slow-release polycarboxylate superplasticizer and preparation method thereof

Abstract

The invention relates to the technical field of water reducing agents, and discloses a slow-release polycarboxylic acid water reducing agent and a preparation method thereof.The slow-release polycarboxylic acid water reducing agent is prepared by adding polyoxyethylene ether, acrylic acid, hydroxyethyl acrylate, a propylene glycol methyl ether acetate chain transfer agent, monoethylene glycol phthalate, hydrogen peroxide, alkenylated silane and water into a stirrer, stirring, adding an initiator, and stirring to obtain a mixture; and finally, obtaining the slow-release polycarboxylic acid water reducer. Quaternary ammonium salt in the slow-release polycarboxylate superplasticizer increases the dispersity to cement particles, so that the surfaces of the cement particles are slightly positively charged, the fluidity of cement paste is increased, the strength of concrete is improved, and silane contained in the slow-release polycarboxylate superplasticizer can deeply permeate into capillary pore walls of the concrete and chemically react with hydrated cement, so that the strength of the concrete is improved. The silane-modified polycarboxylic acid water reducing agent has the advantages that a polysiloxane interpenetrating network structure is formed, the durability of concrete is improved, the content and substitution degree of silane are increased by a hyperbranched structure in the silane-modified polycarboxylic acid water reducing agent, the silane is hydrolyzed firstly in the hydrolysis process of the water reducing agent, and a good slow-release effect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of water reducing agents, in particular to a slow-release polycarboxylic acid water reducing agent and a preparation method thereof. Background Art

[0002] Water reducer is an important component of concrete and plays an important role in improving the performance of concrete. As an additive to concrete, polycarboxylic acid water reducer has a high water reduction rate and plasticity retention. However, concrete is an alkaline environment and polycarboxylic acid water reducer is easily hydrolyzed in concrete. Therefore, there are still deficiencies in some scenarios. For example, patent CN201810885426.8 discloses a cross-linked polycarboxylic acid slow-release water reducer and a preparation method thereof. The invention has a simple process, is easy to operate and has high production efficiency, but its slow-release effect needs to be improved. Summary of the invention

[0003] 1. Technical issues to be solved

[0004] In view of the deficiencies of the prior art, the present invention provides a slow-release polycarboxylate water-reducing agent and a preparation method thereof, which have good slow-release effect.

[0005] (II) Technical solution

[0006] To achieve the above object, the present invention provides the following technical scheme: a slow-release polycarboxylate water-reducing agent and a preparation method thereof, wherein the slow-release polycarboxylate water-reducing agent comprises the following raw materials: 5-15 parts by weight of polyoxyethylene ether, 5-10 parts by weight of acrylic acid, 4-8 parts by weight of hydroxyethyl acrylate, 10-15 parts by weight of propylene glycol methyl ether acetate chain transfer agent, 9-14 parts by weight of monoethylene glycol phthalate, 0.3-3 parts by weight of hydrogen peroxide, 12-25 parts by weight of olefinic silane, and 20-30 parts by weight of water.

[0007] Preferably, the preparation method of the silane-modified polycarboxylate water-reducing agent is:

[0008] (1) adding di(dimethylamino)methylvinylsilane and chloroethanol to N,N-dimethylformamide solvent, stirring to dissolve, reacting at 60-80° C. for 7-12 hours, and then distilling under reduced pressure, filtering and drying to obtain hydroxylated silane;

[0009] (2) adding hydroxylated silane and nitrilotriacetic acid to N,N-dimethylformamide solvent, stirring and mixing, then adding 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide, reacting at 80-95° C. for 5-10 h, precipitating, filtering, and washing after the reaction to obtain intermediate 1;

[0010] (3) Add monoethylene glycol phthalate to the ethanol solvent, then dissolve it by ultrasonication, continue to add hydroxyethyl acrylate and acrylic acid, intermediate 1, and hydrogen peroxide, stir and mix, react at 40-60° C. for 7-10 hours, then add propylene glycol methyl ether acetate chain transfer agent, react at 55-80° C. for 6-8 hours, filter and dry after completion, and obtain a silane-modified polycarboxylic acid water reducer.

[0011] Preferably, the mass ratio of di(dimethylamino)methylvinylsilane to chloroethanol in (1) is 1:1.3-2.2.

[0012] Preferably, the mass ratio of hydroxylated silane, nitrilotriacetic acid, 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide in (2) is 1.2-1.4:1:0.01-0.03:0.02-0.04.

[0013] Preferably, the mass ratio of monoethylene glycol phthalate, hydroxyethyl acrylate, acrylic acid, intermediate 1, hydrogen peroxide, and propylene glycol methyl ether acetate chain transfer agent in (3) is 1:0.8-1.2:1.1-1.3:1.2-1.4:0.2-0.4:1.4-1.8.

[0014] Preferably, the preparation method of the sustained-release polycarboxylate water-reducing agent is as follows: polyoxyethylene ether, acrylic acid, hydroxyethyl acrylate, propylene glycol methyl ether acetate chain transfer agent, monoethylene glycol phthalate, hydrogen peroxide, olefinic silane, and water are added into a stirrer, and stirred for 15-25 minutes to obtain the sustained-release polycarboxylate water-reducing agent.

[0015] (III) Beneficial technical effects

[0016] The invention provides a slow-release polycarboxylic acid water reducer by adding polyoxyethylene ether, acrylic acid, hydroxyethyl acrylate, propylene glycol methyl ether acetate chain transfer agent, monoethylene glycol phthalate, hydrogen peroxide, olefinic silane and water into a stirrer and stirring the mixture.

[0017] The quaternary ammonium salt in the slow-release polycarboxylate water-reducing agent increases the dispersibility of cement particles, making the surface of cement particles slightly positively charged, increasing the fluidity of cement paste, and improving the strength of concrete. The silane contained in it can deeply penetrate the capillary wall of concrete and react chemically with the hydrated cement to form a polysiloxane interpenetrating network structure, thereby improving the durability of concrete. The hyperbranched structure in the silane-modified polycarboxylate water-reducing agent increases the content and degree of substitution of silane, so that the water-reducing agent first hydrolyzes the silane during the hydrolysis process, achieving a better slow-release effect. DETAILED DESCRIPTION

[0018] Example 1

[0019] (1) adding di(dimethylamino)methylvinylsilane and chloroethanol to N,N-dimethylformamide solvent, wherein the mass ratio of di(dimethylamino)methylvinylsilane to chloroethanol is 1:1.3, stirring to dissolve, reacting at 60° C. for 7 h, and then distilling under reduced pressure, filtering and drying to obtain hydroxylated silane;

[0020] (2) adding hydroxylated silane and nitrilotriacetic acid to N,N-dimethylformamide solvent, stirring and mixing, and then adding 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide, wherein the mass ratio of hydroxylated silane, nitrilotriacetic acid, 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide is 1.2:1:0.01:0.02, reacting at 80° C. for 5 h, precipitating, filtering and washing after the reaction to obtain intermediate 1;

[0021] (3) adding monoethylene glycol phthalate to an ethanol solvent, then dissolving it by ultrasonication, continuing to add hydroxyethyl acrylate and acrylic acid, intermediate 1, and hydrogen peroxide, stirring and mixing, reacting at 40° C. for 7 hours, and then adding propylene glycol methyl ether acetate chain transfer agent, wherein the mass ratio of monoethylene glycol phthalate, hydroxyethyl acrylate, acrylic acid, intermediate 1, hydrogen peroxide, and propylene glycol methyl ether acetate chain transfer agent is 1:0.8:1.1:1.2:0.2:1.4, reacting at 55° C. for 6 hours, filtering and drying after completion, to obtain a silane-modified polycarboxylic acid water reducer;

[0022] (4) 5 parts by weight of polyoxyethylene ether, 5 parts by weight of acrylic acid, 4 parts by weight of hydroxyethyl acrylate, 10 parts by weight of propylene glycol methyl ether acetate chain transfer agent, 9 parts by weight of monoethylene phthalate, 0.3 parts by weight of hydrogen peroxide, 12 parts by weight of olefinic silane, and 20 parts by weight of water were added into a stirrer and stirred for 15 minutes to obtain a sustained-release polycarboxylate water-reducing agent.

[0023] Example 2

[0024] (1) adding di(dimethylamino)methylvinylsilane and chloroethanol to N,N-dimethylformamide solvent, wherein the mass ratio of di(dimethylamino)methylvinylsilane to chloroethanol is 1:2.2, stirring and dissolving, reacting at 80° C. for 12 h, and then distilling under reduced pressure, filtering and drying to obtain hydroxylated silane;

[0025] (2) adding hydroxylated silane and nitrilotriacetic acid to N,N-dimethylformamide solvent, stirring and mixing, and then adding 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide, wherein the mass ratio of hydroxylated silane, nitrilotriacetic acid, 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide is 1.4:1:0.03:0.04, reacting at 95° C. for 10 h, precipitating, filtering and washing after the reaction to obtain intermediate 1;

[0026] (3) adding monoethylene glycol phthalate to an ethanol solvent, then dissolving it by ultrasonication, continuing to add hydroxyethyl acrylate and acrylic acid, intermediate 1, and hydrogen peroxide, stirring and mixing, reacting at 60° C. for 10 hours, and then adding propylene glycol methyl ether acetate chain transfer agent, wherein the mass ratio of monoethylene glycol phthalate, hydroxyethyl acrylate, acrylic acid, intermediate 1, hydrogen peroxide, and propylene glycol methyl ether acetate chain transfer agent is 1:1.2:1.3:1.4:0.4:1.8, reacting at 80° C. for 8 hours, filtering and drying after completion, to obtain a silane-modified polycarboxylic acid water reducer;

[0027] (4) 15 parts by weight of polyoxyethylene ether, 10 parts by weight of acrylic acid, 8 parts by weight of hydroxyethyl acrylate, 15 parts by weight of propylene glycol methyl ether acetate chain transfer agent, 14 parts by weight of monoethylene phthalate, 3 parts by weight of hydrogen peroxide, 25 parts by weight of olefinic silane, and 30 parts by weight of water are added to a stirrer and stirred for 25 minutes to obtain a sustained-release polycarboxylate water-reducing agent.

[0028] Example 3

[0029] (1) adding di(dimethylamino)methylvinylsilane and chloroethanol to N,N-dimethylformamide solvent, wherein the mass ratio of di(dimethylamino)methylvinylsilane to chloroethanol is 1:1.3-2.2, stirring to dissolve, reacting at 60-80° C. for 7-12 hours, and then distilling under reduced pressure, filtering and drying to obtain hydroxylated silane;

[0030] (2) adding hydroxylated silane and nitrilotriacetic acid to N,N-dimethylformamide solvent, stirring and mixing, and then adding 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide, wherein the mass ratio of hydroxylated silane, nitrilotriacetic acid, 4-dimethylaminopyridine, and N,N-dicyclohexylcarbodiimide is 1.2-1.4:1:0.01-0.03:0.02-0.04, reacting at 80-95° C. for 5-10 hours, precipitating, filtering, and washing after the reaction to obtain intermediate 1;

[0031] (3) adding monoethylene glycol phthalate to an ethanol solvent, then dissolving it by ultrasonication, continuing to add hydroxyethyl acrylate and acrylic acid, intermediate 1, and hydrogen peroxide, stirring and mixing, reacting at 40-60° C. for 7-10 hours, and then adding propylene glycol methyl ether acetate chain transfer agent, wherein the mass ratio of monoethylene glycol phthalate, hydroxyethyl acrylate, acrylic acid, intermediate 1, hydrogen peroxide, and propylene glycol methyl ether acetate chain transfer agent is 1:0.8-1.2:1.1-1.3:1.2-1.4:0.2-0.4:1.4-1.8, reacting at 55-80° C. for 6-8 hours, filtering and drying after completion, to obtain a silane-modified polycarboxylic acid water reducer;

[0032] (4) 5-15 parts by weight of polyoxyethylene ether, 5-10 parts by weight of acrylic acid, 4-8 parts by weight of hydroxyethyl acrylate, 10-15 parts by weight of propylene glycol methyl ether acetate chain transfer agent, 9-14 parts by weight of monoethylene glycol phthalate, 0.3-3 parts by weight of hydrogen peroxide, 12-25 parts by weight of olefinic silane, and 20-30 parts by weight of water are added into a stirrer and stirred for 15-25 minutes to obtain a sustained-release polycarboxylate water-reducing agent.

[0033] Example 4

[0034] (1) adding di(dimethylamino)methylvinylsilane and chloroethanol to N,N-dimethylformamide solvent, wherein the mass ratio of di(dimethylamino)methylvinylsilane to chloroethanol is 1:1.3, stirring to dissolve, reacting at 60° C. for 7 h, and then distilling under reduced pressure, filtering and drying to obtain hydroxylated silane;

[0035] (2) adding hydroxylated silane and nitrilotriacetic acid to N,N-dimethylformamide solvent, stirring and mixing, and then adding 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide, wherein the mass ratio of hydroxylated silane, nitrilotriacetic acid, 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide is 1.4:1:0.03:0.04, reacting at 95° C. for 10 h, precipitating, filtering and washing after the reaction to obtain intermediate 1;

[0036] (3) adding monoethylene glycol phthalate to an ethanol solvent, then dissolving it by ultrasonication, continuing to add hydroxyethyl acrylate and acrylic acid, intermediate 1, and hydrogen peroxide, stirring and mixing, reacting at 40-60° C. for 7-10 hours, and then adding propylene glycol methyl ether acetate chain transfer agent, wherein the mass ratio of monoethylene glycol phthalate, hydroxyethyl acrylate, acrylic acid, intermediate 1, hydrogen peroxide, and propylene glycol methyl ether acetate chain transfer agent is 1:0.8-1.2:1.1-1.3:1.2-1.4:0.2-0.4:1.4-1.8, reacting at 55-80° C. for 6-8 hours, filtering and drying after completion, to obtain a silane-modified polycarboxylic acid water reducer;

[0037] (4) 5-15 parts by weight of polyoxyethylene ether, 5-10 parts by weight of acrylic acid, 4-8 parts by weight of hydroxyethyl acrylate, 10-15 parts by weight of propylene glycol methyl ether acetate chain transfer agent, 9-14 parts by weight of monoethylene glycol phthalate, 0.3-3 parts by weight of hydrogen peroxide, 12-25 parts by weight of olefinic silane, and 20-30 parts by weight of water are added into a stirrer and stirred for 15-25 minutes to obtain a sustained-release polycarboxylate water-reducing agent.

[0038] Example 5

[0039] (1) adding di(dimethylamino)methylvinylsilane and chloroethanol to N,N-dimethylformamide solvent, wherein the mass ratio of di(dimethylamino)methylvinylsilane to chloroethanol is 1:2.2, stirring and dissolving, reacting at 80° C. for 12 h, and then distilling under reduced pressure, filtering and drying to obtain hydroxylated silane;

[0040] (2) adding hydroxylated silane and nitrilotriacetic acid to N,N-dimethylformamide solvent, stirring and mixing, and then adding 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide, wherein the mass ratio of hydroxylated silane, nitrilotriacetic acid, 4-dimethylaminopyridine, and N,N-dicyclohexylcarbodiimide is 1.2-1.4:1:0.01-0.03:0.02-0.04, reacting at 80-95° C. for 5-10 hours, precipitating, filtering, and washing after the reaction to obtain intermediate 1;

[0041] (3) adding monoethylene glycol phthalate to an ethanol solvent, then dissolving it by ultrasonication, continuing to add hydroxyethyl acrylate and acrylic acid, intermediate 1, and hydrogen peroxide, stirring and mixing, reacting at 40-60° C. for 7-10 hours, and then adding propylene glycol methyl ether acetate chain transfer agent, wherein the mass ratio of monoethylene glycol phthalate, hydroxyethyl acrylate, acrylic acid, intermediate 1, hydrogen peroxide, and propylene glycol methyl ether acetate chain transfer agent is 1:0.8-1.2:1.1-1.3:1.2-1.4:0.2-0.4:1.4-1.8, reacting at 55-80° C. for 6-8 hours, filtering and drying after completion, to obtain a silane-modified polycarboxylic acid water reducer;

[0042] (4) 5 parts by weight of polyoxyethylene ether, 5 parts by weight of acrylic acid, 4 parts by weight of hydroxyethyl acrylate, 10 parts by weight of propylene glycol methyl ether acetate chain transfer agent, 9 parts by weight of monoethylene phthalate, 0.3 parts by weight of hydrogen peroxide, 12 parts by weight of olefinic silane, and 20 parts by weight of water were added into a stirrer and stirred for 15 minutes to obtain a sustained-release polycarboxylate water-reducing agent.

[0043] Comparative Example 1

[0044] (1) 5 parts by weight of polyoxyethylene ether, 5 parts by weight of acrylic acid, 4 parts by weight of hydroxyethyl acrylate, 10 parts by weight of propylene glycol methyl ether acetate chain transfer agent, 9 parts by weight of monoethylene phthalate, 0.3 parts by weight of hydrogen peroxide, and 20 parts by weight of water were added to a stirrer and stirred for 15 minutes to obtain a sustained-release polycarboxylate water-reducing agent.

[0045] The concrete was prepared with the product in the embodiment and comparative example at a dosage of 0.2%, and the mechanical properties of the C30 concrete sample were tested with reference to GB / T50081-2019 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete". The test temperature was room temperature 28°C.

[0046] Table 1 Test data of paste fluidity and concrete 28d strength performance.

[0047]

[0048] It can be seen from Table 1 that Examples 1-5 of the present invention have better sustained release effect and compressive strength than Comparative Example 1.

[0049] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A sustained-release polycarboxylate water-reducing agent, characterized in that: The slow-release polycarboxylate water-reducing agent comprises the following raw materials: 5-15 parts by weight of polyoxyethylene ether, 5-10 parts by weight of acrylic acid, 4-8 parts by weight of hydroxyethyl acrylate, 10-15 parts by weight of propylene glycol methyl ether acetate chain transfer agent, 9-14 parts by weight of monoethylene glycol phthalate, 0.3-3 parts by weight of hydrogen peroxide, 12-25 parts by weight of olefinic silane, and 20-30 parts by weight of water.

2. The sustained-release polycarboxylate water-reducing agent according to claim 1, characterized in that: The preparation method of the silane-modified polycarboxylate water-reducing agent is as follows: (1) adding di(dimethylamino)methylvinylsilane and chloroethanol to N,N-dimethylformamide solvent, stirring to dissolve, reacting at 60-80° C. for 7-12 hours, and then distilling under reduced pressure, filtering and drying to obtain hydroxylated silane; (2) adding hydroxylated silane and nitrilotriacetic acid to N,N-dimethylformamide solvent, stirring and mixing, then adding 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide, reacting at 80-95° C. for 5-10 h, precipitating, filtering, and washing after the reaction to obtain intermediate 1; (3) Add monoethylene glycol phthalate to the ethanol solvent, then dissolve it by ultrasonication, continue to add hydroxyethyl acrylate and acrylic acid, intermediate 1, and hydrogen peroxide, stir and mix, react at 40-60° C. for 7-10 hours, then add propylene glycol methyl ether acetate chain transfer agent, react at 55-80° C. for 6-8 hours, filter and dry after completion, and obtain a silane-modified polycarboxylic acid water reducer.

3. The sustained-release polycarboxylate water-reducing agent according to claim 2, characterized in that: The mass ratio of di(dimethylamino)methylvinylsilane to chloroethanol in (1) is 1:1.3-2.

2.

4. The sustained-release polycarboxylate water-reducing agent according to claim 2, characterized in that: The mass ratio of hydroxylated silane, nitrilotriacetic acid, 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide in (2) is 1.2-1.4:1:0.01-0.03:0.02-0.

04.

5. The sustained-release polycarboxylate water-reducing agent according to claim 2, characterized in that: The mass ratio of monoethylene glycol phthalate, hydroxyethyl acrylate, acrylic acid, intermediate 1, hydrogen peroxide, and propylene glycol methyl ether acetate chain transfer agent in (3) is 1:0.8-1.2:1.1-1.3:1.2-1.4:0.2-0.4:1.4-1.

8.

6. A method for preparing the sustained-release polycarboxylate water-reducing agent according to any one of claims 1 to 5, characterized in that: The preparation method of the slow-release polycarboxylate water reducer comprises the following steps: adding polyoxyethylene ether, acrylic acid, hydroxyethyl acrylate, propylene glycol methyl ether acetate chain transfer agent, monoethylene glycol phthalate, hydrogen peroxide, olefinic silane and water into a stirrer, stirring for 15-25 minutes, and obtaining the slow-release polycarboxylate water reducer after stirring.

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