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Powdery polycarboxylic acid water reducing agent, preparation method therefor and application of powdery polycarboxylic acid water reducing agent

A technology of polycarboxylic acid and water reducing agent, which is applied in the field of polycarboxylic acid water reducing agent, can solve the problems of high preparation temperature, reduced powder performance, and reduced water reducing performance of powder, so as to achieve easy industrial production, improved product performance, and guaranteed The effect of the polymerization process

Active Publication Date: 2017-04-26
SHANGHAI DONGDA CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is to overcome the existing powdery polycarboxylate water-reducing agent prepared by spraying and drying liquid polycarboxylate mother liquor, which has a large energy consumption in the powder spraying process, and the water-reducing performance of the powder is reduced, or is prepared by bulk polymerization. Due to the defects of high temperature, low powder water reducing rate, large dosage, unstable polymerization process, and low proportion of effective molecular structure of the product, a powdery polycarboxylate water reducer and its preparation method and application are provided
The powdery polycarboxylate water-reducer of the present invention adopts step-by-step addition of initiator, and step-by-step, variable-speed addition of active comonomer and chain transfer agent by optimizing the process to optimize the polymerization molecular structure, and the prepared powdery polycarboxylate The water reducing agent has the advantages of good dispersibility, high water reducing rate, low dosage and good slump retention. It effectively solves the problems of powder performance reduction and high production energy consumption caused by mother liquor powder spraying or bulk polymerization. The product is cost-effective. More market value, suitable for industrial production

Method used

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  • Powdery polycarboxylic acid water reducing agent, preparation method therefor and application of powdery polycarboxylic acid water reducing agent
  • Powdery polycarboxylic acid water reducing agent, preparation method therefor and application of powdery polycarboxylic acid water reducing agent
  • Powdery polycarboxylic acid water reducing agent, preparation method therefor and application of powdery polycarboxylic acid water reducing agent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] (1), 100 parts of isopentenyl polyoxyethylene ether with a number average molecular weight of 2000, 1 part of hydroxypropyl acrylate, 1 part of sodium allyl sulfonate, 1 part of 2-acrylamide-2-methyl Sodium propanesulfonate and 0.5 parts of methacrylic acid were poured into the reaction kettle, heated and stirred to melt completely; then after the temperature was raised to 55°C, 0.36 parts of azobisisoheptonitrile was added to initiate the reaction;

[0043] (2) Under stirring at 55°C, add dropwise a mixed solution composed of 0.6 parts of mercaptopropionic acid and 9.5 parts of methacrylic acid for 3 hours, of which 70% of the mixed solution is evenly added in the first 1.5 hours. Add the remaining mixed solution uniformly for 1.5h, and add 0.24 parts of azobisisoheptonitrile during the reaction for 1.5h;

[0044] (3) After the dripping is completed, heat the reaction for 2 hours, slowly add 4 parts of sodium hydroxide, pour it out while it is hot, cool, and pulverize into ...

Embodiment 2

[0046] (1), 100 parts of isopentenyl polyoxyethylene polyoxypropylene ether with a number average molecular weight of 5000, 1 part of sodium styrene sulfonate, 1 part of sodium vinyl sulfonate, 1 part of maleic anhydride and 3 parts Pour the acrylic acid into the reaction kettle, heat and stir to melt it completely; then after the temperature is raised to 65°C, 0.36 parts of ammonium persulfate is added to initiate the reaction;

[0047] (2) Under stirring at 65°C, add dropwise a mixed solution consisting of 2 parts of mercaptopropionic acid and 12 parts of acrylic acid for 2 hours, of which 85% of the mixed solution is uniformly added in the first 1 hour, and then uniformly added in the next 1 hour The remaining mixed solution, and adding 0.24 parts of ammonium persulfate during the reaction for 1 hour;

[0048] (3) After the dripping is completed, heat preservation and reaction for 1 hour, slowly add 6 parts of sodium hydroxide, pour out while hot, cool, and pulverize into 100 me...

Embodiment 3

[0050] (1) Pour 100 parts of isopentenyl polyoxyethylene ether with a number average molecular weight of 4000, 2 parts of acrylic acid, 1 part of sodium methacrylate sulfonate, 1 part of itaconic acid and 1 part of hydroxyethyl acrylate In the reaction kettle, heat and stir to make it melt completely; then after heating to 60°C, add 0.36 parts of peroxydicarbonic acid (bis-2-phenoxyethyl) to initiate the reaction;

[0051] (2) Under stirring at 60°C, add dropwise a mixed solution consisting of 2 parts of thioglycolic acid and 18 parts of acrylic acid for 3 hours, of which 70% of the mixed solution is evenly added in the first 1.5 hours, and the latter 1.5 hours are uniform Add the remaining mixed solution, and add 0.24 parts of peroxydicarbonic acid (bis-2-phenoxyethyl ester) during the reaction for 1.5 hours;

[0052] (3) After the dripping is completed, heat the reaction for 1.5 hours, pour it out while it is hot, cool, and pulverize into 400 mesh solid particles to obtain a powd...

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Abstract

The invention discloses a powdery polycarboxylic acid water reducing agent and a preparation method therefor. The water reducing agent contains the following ingredients: 100 parts of macromonomer A, 10-20 parts of monomer B, 0.6-2 parts of initiator and 0.6-2 parts of chain transfer agent, wherein the macromonomer A is R1-O-[CH2-CH2O]m-[CH2-CH(CH3)O]n-R2; and the monomer B is liquid-state unsaturated carboxylic acid. The method comprises the steps: mixing the macromonomer A with 5% to 20% of the monomer B, heating the mixture to 50 DEG C to 70 DEG C, and adding 60% to 80% of the initiator into the mixture; dropwise adding a mixed solution of the chain transfer agent and the rest of the monomer B, wherein the time for dropwise adding is 2 to 4 hours, 60% to 85% of the mixed solution is dropwise added uniformly in first 1 / 2 to 2 / 3 of the time, and the rest of the mixed solution is dropwise added uniformly in remaining time; and carrying out a heat-preservation reaction for 1 to 2 hours, and then, carrying out cooling and crushing. The powdery polycarboxylic acid water reducing agent disclosed by the invention is good in dispersity, high in water reducing rate, small in blended amount and good in slump loss resistant performance.

Description

Technical field [0001] The invention relates to a polycarboxylic acid water reducer for concrete and mortar, in particular to a powdered polycarboxylic acid water reducer and a preparation method and application thereof. Background technique [0002] As a major component of modern concrete, in addition to cement, sand, stone, water, and admixtures, water reducer has promoted the development of concrete technology. Its main function is to improve the workability of fresh concrete, optimize the proportion of concrete, improve concrete performance and reduce costs, and can also give hardened concrete materials different properties to meet various engineering requirements. [0003] With the emergence of polycarboxylic acid water-reducing agent, with its flexible molecular design, it is possible to prepare water-reducing agent products with different properties such as high slump retention, high water reduction, early strength, retardation, air entrainment, shrinkage reduction, etc. acc...

Claims

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Application Information

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IPC IPC(8): C04B24/26C04B24/16C04B24/22C04B103/30
Inventor 董建国王万林罗琼李亚杰高振伟杜辉
Owner SHANGHAI DONGDA CHEM
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