Preparation method and application of polycarboxylic acid-based high-efficiency water reducing agent

Abstract

The present invention relates to the technical field of water reducers, and discloses a preparation method and application of a novel polycarboxylic acid-based high-efficiency water reducer. The present invention uses 1,6-hexanediamine and γ-glycidyloxypropyltrimethoxysilane as raw materials, and obtains intermediate 1 through a ring-opening reaction. Intermediate 2 is obtained by ring-opening alkylation of intermediate 1 and 1,3-propanesulfonic acid lactone, and then reacts it with allyl chloride through a quaternization reaction to obtain intermediate 3. The preparation method is simple and the structure is novel. Then, ammonium persulfate is used as an initiator, mercaptopropionic acid is used as a chain transfer agent, ethylene glycol monovinyl polyethylene glycol ether and acrylic acid, intermediate 3 are copolymerized monomers, and a novel polycarboxylic acid-based high-efficiency water reducer is obtained through a free radical reaction. The polycarboxylic acid water reducer prepared by the present invention has good mud resistance and fluidity.

Description

Technical Field

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

[0002] For modern concrete, water reducers play a very important role in improving the working performance of concrete. As one of the important admixtures of modern concrete, polycarboxylic acid water reducers have the advantages of low dosage, high water reduction rate, and green environmental protection. However, with the continuous reduction of high-quality sand and gravel resources, the increase in mud content in inferior sand and gravel and machine-made sand will greatly affect the performance of polycarboxylic acid water reducers, resulting in poor fluidity of concrete, low strength and other temperatures. Therefore, the development of polycarboxylic acid water reducers with anti-mud ability has become a hot topic in the industry.

[0003] Organosilane contains both organic active functional groups and inorganic single molecular structure, and is a low molecular polymer with a special structure, which can be used as a coupling agent for inorganic and organic materials. For example, the main chain of the invention is composed of organosilane structural units and polyether units, and the prepared polycarboxylate water reducer has good dispersibility and cement adaptability, but does not improve the anti-mud performance of the polycarboxylate water reducer. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies of the prior art, the present invention provides a preparation method and application of a polycarboxylic acid-based high-efficiency water reducer. The prepared water reducer has good mud resistance and flow properties.

[0006] (II) Technical solution

[0007] A preparation method of a polycarboxylic acid-based high-efficiency water reducing agent, the preparation method is as follows:

[0008] Step (1), under nitrogen atmosphere, 1,6-hexanediamine and γ-glycidyloxypropyltrimethoxysilane are added to N,N-dimethylformamide solvent, stirred and dispersed, reacted at 80-90°C for 5-10h, and after the reaction, washed with ethanol and dried to obtain intermediate 1, whose reaction formula is: .

[0009] Step (2), adding intermediate 1 and 1,3-propanesulfonic acid lactone to methanol solvent, stirring and dispersing, reacting at 60-70° C. for 24-48 hours, adding sodium carbonate thereto after the reaction, and continuing the reaction for 2-4 hours, filtering, distilling under reduced pressure, and drying to obtain intermediate 2, the reaction formula of which is: .

[0010] Step (3), add intermediate 2 and propylene chloride to ethanol solvent, stir and disperse, react at 55-75°C for 6-12 hours, and after the reaction, distill under reduced pressure, wash with acetone, dry, filter and dry to obtain intermediate 3, whose reaction formula is: .

[0011] Step (4), adding ethylene glycol monovinyl polyglycol ether to deionized water, stirring to dissolve, then adding acrylic acid, intermediate 3, ammonium persulfate, and 3-mercaptopropionic acid thereto, stirring to disperse, and continuing the reaction for 30-80 minutes. After the reaction is completed, adding 30% sodium hydroxide thereto to adjust the pH to 6-7, thereby obtaining a polycarboxylic acid-based high-efficiency water reducer.

[0012] Preferably, in step (1), the molar ratio of 1,6-hexanediamine to γ-glycidyloxypropyltrimethoxysilane is 1:2-2.5.

[0013] Preferably, in step (2), the molar ratio of the intermediate 1, 1,3-propanesulfonate, and sodium carbonate is 1:2.2-3:2.5-3.

[0014] Preferably, in step (3), the molar ratio of intermediate 2 to allyl chloride is 1:2-2.5.

[0015] Preferably, in step (4), the molar ratio of ethylene glycol monovinyl polyglycol ether, acrylic acid, and intermediate 3 is 1:4-6:0.2-1.5.

[0016] Preferably, in step (4), the amounts of ammonium persulfate and 3-mercaptopropionic acid are 0.3-0.8% and 2-4.5% of the total amount of acrylic acid and intermediate 3, respectively.

[0017] Preferably, the polycarboxylic acid-based high-efficiency water reducing agent prepared by the preparation method is used in cement.

[0018] 3. Beneficial technical effects

[0019] The present invention uses 1,6-hexanediamine and γ-glycidyloxypropyltrimethoxysilane as raw materials, obtains intermediate 1 through a ring-opening reaction, uses intermediate 1 and 1,3-propanesulfonic acid lactone to undergo a ring-opening alkylation to obtain intermediate 2, and then reacts the intermediate with allyl chloride to obtain intermediate 3 through a quaternization reaction. The preparation method is simple and the structure is novel. Then, ammonium persulfate is used as an initiator, mercaptopropionic acid is used as a chain transfer agent, ethylene glycol monovinyl polyglycol ether, acrylic acid, and intermediate 3 are used as copolymer monomers, and a polycarboxylic acid-based high-efficiency water reducer is obtained through a free radical reaction.

[0020] The present invention grafts silane groups, sulfonate structures and quaternary ammonium salt structures into the molecular structure of polycarboxylate water-reducing agent, wherein the alkoxy groups in the silane groups generate silanol groups by hydrolysis, and form Si-O-Si chemical bonds with the hydroxyl groups on the cement-based surface, and connect the water-reducing agent to the cement-based surface in the form of chemical bonds, thereby improving the adsorption capacity of the water-reducing agent on the cement surface, improving fluidity, and extending the cement hydration time. The sulfonate structure is a structure with a strong polarity, which can reduce the charge density of the water-reducing agent, improve the adsorption capacity of the water-reducing agent, and the sulfonate structure also has a strong adsorption capacity for clays such as bentonite, thereby improving the anti-mud performance of the polycarboxylate water-reducing agent. In addition, the quaternary ammonium salt structure contained therein carries a positive charge, and can produce adsorption with clays such as bentonite with a negative charge, further improving the anti-mud performance of the polycarboxylate water-reducing agent, and improving the fluidity of the polycarboxylate water-reducing agent. The polycarboxylate water-reducing agent prepared by the present invention has good anti-mud performance and fluidity. DETAILED DESCRIPTION

[0021] The following non-limiting embodiments may enable a person skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.

[0022] Cement: Ordinary Portland cement P·O42.5.

[0023] Example 1

[0024] Step (1), under nitrogen atmosphere, add 0.2 mol of 1,6-hexanediamine and 0.4 mol of γ-glycidyloxypropyltrimethoxysilane to N,N-dimethylformamide solvent, stir and disperse, react at 85°C for 6 hours, and after the reaction is completed, wash with ethanol and dry to obtain intermediate 1.

[0025] Step (2), add 0.1 mol of intermediate 1 and 0.3 mol of 1,3-propanesulfonic acid lactone into methanol solvent, stir and disperse, react at 65°C for 48 hours, and after the reaction is completed, add 0.28 mol of sodium carbonate and continue to react for 3 hours. After the reaction is completed, filter, distill under reduced pressure, and dry to obtain intermediate 2.

[0026] Step (3), add 0.2 mol of intermediate 2 and 0.45 mol of allyl chloride into ethanol solvent, stir and disperse, react at 60°C for 8 hours, and after the reaction is completed, distill under reduced pressure, wash with acetone, dry, filter and dry to obtain intermediate 3.

[0027] Step (4), adding 0.1 mol of ethylene glycol monovinyl polyglycol ether to deionized water, stirring to dissolve, then adding 0.6 mol of acrylic acid, 0.02 mol of intermediate 3, 0.001 mol of ammonium persulfate, and 0.008 mol of mercaptopropionic acid, stirring to disperse, and continuing the reaction for 80 minutes. After the reaction is completed, adding 30% sodium hydroxide to adjust the pH to 6, to obtain a polycarboxylic acid-based high-efficiency water reducer.

[0028] Example 2

[0029] Step (1), under nitrogen atmosphere, add 0.2 mol of 1,6-hexanediamine and 0.5 mol of γ-glycidyloxypropyltrimethoxysilane into N,N-dimethylformamide solvent, stir and disperse, react at 80° C. for 10 h, and after the reaction is completed, wash with ethanol and dry to obtain intermediate 1.

[0030] Step (2), add 0.1 mol of intermediate 1 and 0.25 mol of 1,3-propanesulfonic acid lactone into methanol solvent, stir and disperse, react at 65°C for 48 hours, and after the reaction, add 0.3 mol of sodium carbonate and continue to react for 3 hours. After the reaction, filter, distill under reduced pressure, and dry to obtain intermediate 2.

[0031] Step (3), add 0.2 mol of intermediate 2 and 0.4 mol of allyl chloride into ethanol solvent, stir and disperse, react at 70°C for 10 hours, and after the reaction is completed, distill under reduced pressure, wash with acetone, dry, filter and dry to obtain intermediate 3.

[0032] Step (4), adding 0.1 mol of ethylene glycol monovinyl polyglycol ether to deionized water, stirring to dissolve, then adding 0.5 mol of acrylic acid, 0.15 mol of intermediate 3, 0.006 mol of ammonium persulfate, and 0.033 mol of mercaptopropionic acid, stirring to disperse, and continuing the reaction for 60 minutes. After the reaction is completed, adding 30% sodium hydroxide to adjust the pH to 6, to obtain a polycarboxylic acid-based high-efficiency water reducer.

[0033] Example 3

[0034] Step (1), under nitrogen atmosphere, add 0.2 mol of 1,6-hexanediamine and 0.45 mol of γ-glycidyloxypropyltrimethoxysilane into N,N-dimethylformamide solvent, stir and disperse, react at 90° C. for 5 h, and after the reaction is completed, wash with ethanol and dry to obtain intermediate 1.

[0035] Step (2), add 0.1 mol of intermediate 1 and 0.22 mol of 1,3-propanesulfonic acid lactone into methanol solvent, stir and disperse, react at 70°C for 48 hours, and after the reaction, add 0.3 mol of sodium carbonate and continue to react for 3 hours. After the reaction, filter, distill under reduced pressure, and dry to obtain intermediate 2.

[0036] Step (3), add 0.2 mol of intermediate 2 and 0.45 mol of allyl chloride to ethanol solvent, stir and disperse, react at 55° C. for 12 h, and after the reaction is completed, distill under reduced pressure, wash with acetone, dry, filter and dry to obtain intermediate 3.

[0037] Step (4), adding 0.1 mol of ethylene glycol monovinyl polyglycol ether to deionized water, stirring to dissolve, then adding 0.4 mol of acrylic acid, 0.15 mol of intermediate 3, 0.0012 mol of ammonium persulfate, and 0.033 mol of mercaptopropionic acid, stirring to disperse, and continuing the reaction for 50 minutes. After the reaction is completed, adding 30% sodium hydroxide to adjust the pH to 7, to obtain a polycarboxylic acid-based high-efficiency water reducer.

[0038] Example 4

[0039] Step (1), under nitrogen atmosphere, add 0.2 mol of 1,6-hexanediamine and 0.4 mol of γ-glycidyloxypropyltrimethoxysilane to N,N-dimethylformamide solvent, stir and disperse, react at 85° C. for 10 h, and after the reaction is completed, wash with ethanol and dry to obtain intermediate 1.

[0040] Step (2), add 0.1 mol of intermediate 1 and 0.3 mol of 1,3-propanesulfonic acid lactone into methanol solvent, stir and disperse, react at 65°C for 24 hours, and after the reaction, add 0.25 mol of sodium carbonate and continue to react for 4 hours. After the reaction, filter, distill under reduced pressure, and dry to obtain intermediate 2.

[0041] Step (3), add 0.2 mol of intermediate 2 and 0.5 mol of allyl chloride into ethanol solvent, stir and disperse, react at 65° C. for 6 h, and after the reaction is completed, distill under reduced pressure, wash with acetone, dry, filter and dry to obtain intermediate 3.

[0042] Step (4), adding 0.1 mol of ethylene glycol monovinyl polyglycol ether to deionized water, stirring to dissolve, then adding 0.5 mol of acrylic acid, 0.1 mol of intermediate 3, 0.006 mol of ammonium persulfate, and 0.02 mol of mercaptopropionic acid, stirring to disperse, and continuing the reaction for 50 minutes. After the reaction is completed, adding 30% sodium hydroxide to adjust the pH to 7, to obtain a polycarboxylic acid-based high-efficiency water reducer.

[0043] Example 5

[0044] Step (1), under nitrogen atmosphere, add 0.2 mol of 1,6-hexanediamine and 0.4 mol of γ-glycidyloxypropyltrimethoxysilane to N,N-dimethylformamide solvent, stir and disperse, react at 85° C. for 10 h, and after the reaction is completed, wash with ethanol and dry to obtain intermediate 1.

[0045] Step (2), add 0.1 mol of intermediate 1 and 0.25 mol of 1,3-propanesulfonic acid lactone into methanol solvent, stir and disperse, react at 60°C for 36 hours, and after the reaction, add 0.28 mol of sodium carbonate and continue to react for 2 hours. After the reaction, filter, distill under reduced pressure, and dry to obtain intermediate 2.

[0046] Step (3), add 0.2 mol of intermediate 2 and 0.4 mol of allyl chloride into ethanol solvent, stir and disperse, react at 75°C for 10 hours, and after the reaction is completed, distill under reduced pressure, wash with acetone, dry, filter and dry to obtain intermediate 3.

[0047] Step (4), adding 0.1 mol of ethylene glycol monovinyl polyglycol ether to deionized water, stirring to dissolve, then adding 0.5 mol of acrylic acid, 0.018 mol of intermediate 3, 0.001 mol of ammonium persulfate, and 0.02 mol of mercaptopropionic acid, stirring to disperse, and continuing the reaction for 30 minutes. After the reaction is completed, adding 30% sodium hydroxide to adjust the pH to 7, to obtain a polycarboxylic acid-based high-efficiency water reducer.

[0048] Comparative Example 1

[0049] The difference between this comparative example and Example 1 is that in step (4), intermediate 3 is not contained.

[0050] With reference to GB / T8077-2012, montmorillonite and polycarboxylate water reducer were added to cement by pre-mixing and internal mixing. The amount of montmorillonite was 1% of the cement mass, and the amount of water reducer was 0.2% of the cement mass. The fluidity at 0h and 1h was measured.

[0051]

[0052] It can be seen from the table that the mud resistance of Examples 1-5 is greater than that of Comparative Example 1, the maximum fluidity at 0h reaches 290mm, and the maximum fluidity at 1h reaches 270mm.

[0053] According to GB / T8077-2012, the cement paste fluidity test was carried out with a water-cement ratio of 0.29 and a polycarboxylate water-reducing agent content of 0.2%. The fluidity at 0h and 1h was measured.

[0054]

[0055] It can be seen from the table that the polycarboxylate water-reducing agent prepared by the present invention has good dispersion fluidity, with a maximum fluidity of 320 mm at 0 h and a maximum fluidity of 305 mm at 1 h.

[0056] The above description of the embodiments is to facilitate the understanding and application of the present invention by those skilled in the art. It is obvious that those familiar with the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the embodiments herein, and modifications made to the present invention by those skilled in the art based on the disclosure of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing a polycarboxylic acid-based high-efficiency water reducing agent, characterized in that: The preparation method is as follows: Step (1), under nitrogen atmosphere, 1,6-hexanediamine and γ-glycidyloxypropyltrimethoxysilane are added to N,N-dimethylformamide solvent, stirred and dispersed, reacted at 80-90° C. for 5-10 hours, and after the reaction, washed with ethanol and dried to obtain intermediate 1; Step (2), adding intermediate 1 and 1,3-propanesulfonate to a methanol solvent, stirring and dispersing, reacting at 60-70° C. for 24-48 hours, adding sodium carbonate thereto after the reaction is completed, and continuing the reaction for 2-4 hours, filtering, distilling under reduced pressure, and drying to obtain intermediate 2; Step (3), adding intermediate 2 and propylene chloride to ethanol solvent, stirring and dispersing, reacting at 55-75°C for 6-12 hours, and after the reaction is completed, distilling under reduced pressure, washing with acetone, drying, filtering, and drying to obtain intermediate 3; Step (4), adding ethylene glycol monovinyl polyglycol ether to deionized water, stirring to dissolve, then adding acrylic acid, intermediate 3, ammonium persulfate, and 3-mercaptopropionic acid thereto, stirring to disperse, and continuing the reaction for 30-80 minutes. After the reaction is completed, adding 30% sodium hydroxide thereto to adjust the pH to 6-7, thereby obtaining a polycarboxylic acid-based high-efficiency water reducer.

2. The method for preparing a polycarboxylic acid-based high-efficiency water reducing agent according to claim 1, characterized in that: In the step (1), the molar ratio of 1,6-hexanediamine to γ-glycidyloxypropyltrimethoxysilane is 1:2-2.

5.

3. The method for preparing a polycarboxylic acid-based high-efficiency water reducing agent according to claim 1, characterized in that: In the step (2), the molar ratio of the intermediate 1, 1,3-propanesulfonate, and sodium carbonate is 1:2.2-3:2.5-3.

4. The method for preparing a polycarboxylic acid-based high-efficiency water reducing agent according to claim 1, characterized in that: In the step (3), the molar ratio of the intermediate 2 to allyl chloride is 1:2-2.

5.

5. The method for preparing a polycarboxylic acid-based high-efficiency water reducing agent according to claim 1, characterized in that: In the step (4), the molar ratio of ethylene glycol monovinyl polyglycol ether, acrylic acid, and intermediate 3 is 1:4-6:0.2-1.

5.

6. The method for preparing a polycarboxylic acid-based high-efficiency water reducing agent according to claim 1, characterized in that: In the step (4), the amounts of ammonium persulfate and 3-mercaptopropionic acid are 0.3-0.8% and 2-4.5% of the total amount of acrylic acid and intermediate 3, respectively.

7. Use of the polycarboxylic acid-based high-efficiency water reducing agent prepared according to the preparation method according to any one of claims 1 to 6 in cement.

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