Method for preparing amide/imide type high-concentration polycarboxylic acid high-performance water reducer

Abstract

The invention discloses a method for preparing an amide / imide type high-concentration polycarboxylic acid high-performance water reducer, which comprises the following: (1) a step of acylation reaction, which is to react unsaturated anhydride and monohydric alcohol amine to obtain an acylated product A; (2) a step of esterification, which is to perform the catalytic esterification of polyoxyalkylene glycol monoalkyl ether and unsaturated acid (anhydride) to obtain an esterified product B; (3) a step of copolymerization, which is to subject the acylated product A, the esterified product B and a sulfonic acid small monomer C to free radical copolymerization under the action of an initiator and a copolymerization regulator to obtain a copolymerized product at a concentration of 70 to 85 percent; and (4) a step of neutralization reaction, which is to regulate the pH value of the copolymerized product to 6 to 7 to obtain the polycarboxylic acid high-performance water reducer at a concentration of 70 to 85 percent. The method can regulate the performance of the product by controlling the structure of the product, avoid using solvent in a reaction process, and is safe, pollution-free andenvironmentally-friendly, and the obtained product is stable in performance and has high slump keeping performance and water reducing performance.

Description

technical field [0001] The invention belongs to the technical field of chemical building materials, in particular to a preparation method of an amide / imide high-concentration polycarboxylic acid-based high-performance water reducer. Background technique [0002] Concrete admixture is the sixth component in concrete except cement, sand, stone, water, and mineral admixtures. It plays a very important role in the application of high performance concrete. In recent years, the research and production of concrete superplasticizers have developed towards the direction of high performance and pollution-free. Polycarboxylate high-efficiency water reducer has a comb-shaped molecular structure. It has the advantages of high water reducing rate, excellent slump retention performance, adjustable setting time, low shrinkage rate, good concrete appearance quality, low alkali content and chloride ion content, and good adaptability to cementitious materials. Foreign studies have shown tha...

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Problems solved by technology

[0005] Chinese Patent Publication Nos. CN 1673162 A and CN 1673163 A respectively disclose a preparation method of an amphoteric carboxylic acid comb-shaped graft copolymer concrete superplasticizer, but the synthesis process is relatively complicated, and the raw materials used are not currently commonly used in the market. It is not easy to carry out actual production, and its synthetic concentration can only reach 40%

[0006] Chinese Patent Publication No. CN 101701050 A discloses a preparation method of a comb-shaped cement dispersant and the comb-shaped cement dispersant also adds an amide / imide structure to the product molecule during synthesis, but there are also monomers used for copolymerization. The body is relatively special, which is not conducive to the shortcomings of industrialization, and its highest synthesis concentration can only reach 60%.

[0007] Patents such as Chinese Patent Publication No. CN 101475339 A, CN 101475670 A, CN 1667009 A, and CN 101531480 A all mention the method of adding unsaturated amides / imides such as acrylamide during copolymerization to prepare amide / imide based polycarboxylate water reducer, but commonly used acrylamide is expensive and highly toxic, and is not very suitable for the production of water reducers, while other unsaturated amides / imides also have similar problems, and some The structure of unsaturated amides / imides is special, and the supply in the market is very small, or even generally unavailable. It needs to be customized with a special manufacturer, which will cost more and be very troublesome.

[0008] Chinese Patent Publication No. CN 101665558 A discloses a preparation method of a cement dispersant containing amide polyamine structural units, and also mentions the use of amidation to synthesize monomers with amide polyamine structures, but the amidation process It is complicated and needs to add water-carrying agent, which is not economical enough

[0009] Chinese Patent Publication No. CN 101539352 A discloses a preparation method of an amphoteric vinyl polymer water reducer, which uses triethanolamine, maleic anhydride and citric acid to react, since triethanolamine contains three amine groups, it may interact with If more than one maleic anhydride reacts, there will be a danger of gelation during subsequent copolymerization, so its synthesis concentration is difficult to increase, and the synthesis concentration reported in the patent does not exceed 30%.

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