Modified starch water reducing agent and preparation method and use method thereof

A technology of water reducing agent and modification, which is applied in the field of modified starch water reducing agent and its preparation, which can solve the problems of sensitivity to mud content, influence on popularization, decrease of water reducing rate and fluidity, etc., and increase retarding time , prevent water loss and improve adaptability

Active Publication Date: 2015-03-11
FUSHUN LUTONG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The water-reducing rate of the third-generation water-reducing agent can be as high as 30% or more, and the general dosage is 0.2% of the cement weight. Formaldehyde is not used as a raw material in the preparation process, and there is no formaldehyde pollution. It has the characteristics of low dosage and environmental protection, but there are The disadvantage is that it has adaptability to cement and is sensitive to the mud content in sand and gravel. When the mud content of sand and gravel is greater than 5%, its water reducing rate and fluidity will drop significantly, which seriously affects its popularization and use.

Method used

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preparation example Construction

[0017] A kind of preparation method of modified starch water reducing agent of the present invention, comprises the following steps:

[0018] (1) Preparation of degraded starch: put 20-25 parts of cornstarch into a reactor containing 80-90 parts of water in parts by mass, add 1-2 parts of sodium carbonate under stirring, and add it when the temperature rises to 50-60°C 1-3 parts of oxidizing agent, continue to heat up to 90-95° C., and keep warm for 3-3.5 hours to obtain a modified and degraded starch solution.

[0019] (2) Preparation of modified starch water reducer: heat or cool down the degraded starch solution prepared above to 80-85°C, add 10-14 parts of mixed monomers and 2-2 parts in 5 times within 30-40 minutes. 4 parts of initiator, then continue to keep warm for 3 to 4 hours, cool down to 30 to 40 °C, add 1 to 1.5 parts of retarder, mix evenly, and adjust the pH value to 7.0 to 7.0 with a mass fraction of 20% sodium hydroxide solution 7.5 The modified starch water ...

Embodiment 1

[0024] A kind of preparation method of modified starch water reducing agent, comprises the following steps:

[0025] (1) Preparation of degraded starch: put 20 parts of cornstarch into a reactor containing 80 parts of water in parts by mass, add 2 parts of sodium carbonate under stirring, add 1 part of hydrogen peroxide when heating to 50 ° C, and continue to heat up to 90 ℃, heat preservation reaction for 3 hours to obtain a modified degraded starch solution.

[0026] (2) Preparation of modified starch water reducer: heat or cool down the degraded starch solution prepared above to 80°C, add 10 parts of mixed monomer and 4 parts of cerium ammonium nitrate in 5 times within 30 minutes, and then continue Insulate and react for 3 hours, lower the temperature to 40°C, add 1 part of sodium gluconate, mix evenly, and adjust the pH value to 7.0 with 20% sodium hydroxide solution to obtain a modified starch water reducer.

Embodiment 2

[0028] A preparation method of modified starch water reducer, comprising the following steps:

[0029] (1) Preparation of degraded starch: put 25 parts of cornstarch into a reactor containing 90 parts of water in parts by mass, add 1 part of sodium carbonate under stirring, add 2 parts of ammonium persulfate when heating to 60 ° C, and continue to heat up to 95° C., heat preservation reaction for 3.5 hours to obtain a modified and degraded starch solution.

[0030] (2) Preparation of modified starch water reducer: heat or cool down the degraded starch solution prepared above to 85°C, add 12 parts of mixed monomer and 2 parts of hydrogen peroxide in 5 times within 30 minutes, and then continue the heat preservation reaction After 3 hours, cool down to 40°C, add 1.5 parts of sodium tripolyphosphate, mix evenly, and adjust the pH value to 7.5 with 20% sodium hydroxide solution to obtain a modified starch water reducer.

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Abstract

The invention discloses a modified starch water reducing agent and a preparation method and a use method thereof; with natural starch as a main raw material, the modified starch water reducing agent is prepared through oxidative degradation and grafting copolymerization reaction with a mixed monomer and has the characteristics of high water reducing rate, strong adaptability, good delayed coagulation effect and good compatibility with other additives, the water reducing rate can reach 26-28%, and the delayed coagulation time is 3-4 hours. When the product prepared by the method is in cooperation use with a polycarboxylate-type water reducing agent, can increase the delayed coagulation time of the polycarboxylate-type water reducing agent to reach 4-5 hours, can effectively prevent the polycarboxylate-type water reducing agent from generating water overflowing, segregation and other phenomena, and improves the adaptability of the polycarboxylate-type water reducing agent on mud-containing dinas.

Description

【Technical field】 [0001] The invention belongs to the technical field of concrete water-reducer, and relates to a modified starch water-reducer used in concrete construction and its preparation method and use method. 【Background technique】 [0002] Concrete water reducing agent is an admixture that must be used in the production and construction of modern concrete. Its function is to reduce the water consumption during concrete mixing under the condition of ensuring the fluidity of the new concrete, and to promote the hydration reaction of cement in concrete. Improve the strength and service life of concrete. The main concrete water reducers currently used in my country are the second generation water reducer naphthalene sulfonate formaldehyde condensate, sulfonated melamine formaldehyde condensate and sulfamate condensate, the third generation water reducer polycarboxylate water reducer Agents are being promoted and applied. The output of the second-generation water reduce...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B24/38C04B103/30
Inventor 吕生华赵浩然贺亚亚孙世彧周庆芳曾桥
Owner FUSHUN LUTONG CHEM
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