A kind of synthetic method of polycarboxylate water-reducer containing siloxyl group

A synthesis method and technology of siloxy group are applied in the synthesis field of polycarboxylate water reducing agent to achieve excellent retardation and plastic preservation effect, avoid condensation reaction, and avoid the effect of not being able to function effectively.

Active Publication Date: 2021-02-02
SHANGHAI TAIJIE CHEM
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  • Application Information

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Problems solved by technology

In addition, in the existing synthesis process, when organosilicon compounds are applied to the synthesis of polycarboxylate superplasticizers, it is impossible to completely avoid the hydrolysis reaction of the silicon-oxygen bond of the silane coupling agent under acidic water phase conditions, so that it is impossible to avoid the hydrolysis reaction. The generated silanol condensation reaction affects the performance of the water reducer

Method used

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  • A kind of synthetic method of polycarboxylate water-reducer containing siloxyl group
  • A kind of synthetic method of polycarboxylate water-reducer containing siloxyl group
  • A kind of synthetic method of polycarboxylate water-reducer containing siloxyl group

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preparation example Construction

[0022]In a preferred embodiment, the method for synthesizing the polycarboxylic acid water reducing agent containing siloxy groups includes the following steps:

[0023]S1: Add dried maleic anhydride and dried silane coupling agent to the first reaction vessel, and mechanically stir for 30min~150min at a reaction temperature of 0℃~10℃, and the reaction will be complete to produce organic silicon. Polymer

[0024]S2: Add the silicone oligomer, organic solvent and initiator to the second reaction vessel, and add the unsaturated carboxylic acid monomer dropwise at a constant rate (after 1.5h to 3.5h), at 55°C to 85°C Under the reaction temperature, mechanical stirring reaction (total reaction time 2.5h-6h), add ethanol solution of sodium hydroxide to adjust the pH value to 7.0-8.5, after the organic solvent is evaporated under reduced pressure, the siloxy-containing Polycarboxylic acid water reducing agent.

[0025]In a preferred embodiment, in S1, the silane coupling agent is γ-aminopropyl tri...

Embodiment 1

[0040]S1: Add 1000g of dried maleic anhydride and 2000g of dried γ-aminopropyltriethoxysilane to the first reaction vessel, and mechanically stir for 90 minutes at a reaction temperature of 5°C. The reaction is complete to produce Silicone oligomer;

[0041]S2: Add 250g of the organosilicon oligomer, 500ml of toluene and 10g of azobisisobutyronitrile to the second reaction vessel, and add 700g of acrylic acid dropwise at a constant rate (after 2.5h), at a reaction temperature of 65°C , Mechanical stirring reaction (total reaction time 3.5h), after the reaction is complete, add 20wt% sodium hydroxide ethanol solution to adjust the pH to 7.5, after the organic solvent is evaporated under reduced pressure, the polycarboxylic acid containing siloxy group is obtained. Liquid ①.

Embodiment 2

[0043]S1: Add 1000g of dried maleic anhydride and 1500g of dried γ-aminopropyltrimethoxysilane to the first reaction vessel, and mechanically stir for 60min at a reaction temperature of 8°C. The reaction is complete to produce organic Silicon oligomer;

[0044]S2: Add 200g of the silicone oligomer, 500ml of n-hexane and 15g of benzoyl peroxide to the second reaction vessel, and add 800g of methacrylic acid dropwise at a constant rate (after 3.5h), the reaction will be carried out at 75°C Under the temperature, mechanical stirring reaction (total reaction time 5.5h), after the reaction is complete, add 20wt% sodium hydroxide in ethanol to adjust the pH to 8.0, after the organic solvent is evaporated under reduced pressure, the polycarboxylate containing siloxy is obtained. Acid water reducing agent②.

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Abstract

The invention provides a method for synthesizing a polycarboxylate water reducer containing siloxy groups, which comprises the following steps: S1: adding maleic anhydride and a silane coupling agent, at a reaction temperature of 0°C to 10°C , the reaction is complete to generate silicone oligomers; S2: Add the silicone oligomers, organic solvent and initiator, and add unsaturated carboxylic acid monomer dropwise at a uniform speed. After the reaction is complete, after treatment, the target product can be obtained. The polycarboxylate superplasticizer containing silaneoxy group exhibits excellent retarding and plastic preservation effect, and because of the use of an organic solvent system, it avoids the formation of silane coupling agent after hydrolysis of silicon methoxy or silicon ethoxy The silanol condensation reaction occurs, thereby avoiding the adverse effect that ordinary polycarboxylate superplasticizers cannot effectively function in precast concrete. Both the initial performance and the time-lapse performance of the polycarboxylate water reducer containing siloxy groups are significantly better than commercially available common polycarboxylate water reducers.

Description

Technical field[0001]The invention belongs to the technical field of building admixtures, and in particular relates to a method for synthesizing a polycarboxylic acid water reducing agent containing siloxy groups.Background technique[0002]Polycarboxylic acid type water reducer is the third generation concrete admixture after lignosulfonate type water reducer and naphthalene type water reducer. It is currently used in various industrial buildings, civil buildings, roads and bridges at home and abroad. Widely used; polycarboxylate water-reducing agent has become the most widely used and the largest amount of building admixture, in some engineering fields, such as nuclear power engineering, high-strength concrete (C60 and above), ultra-high-strength concrete (C80 and above) ), high-speed railway engineering, high-rise / super high-rise pumping and other concrete applications play an irreplaceable role.[0003]In the prior art, the ratio of reactants, reaction conditions and synthesis proce...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B24/26C08F220/06C08F230/08C04B103/30
CPCC04B24/2652C04B2103/302C08F220/06C08F230/08
Inventor 朱伟亮王少峰
Owner SHANGHAI TAIJIE CHEM
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