Method for stably synthesizing polycarboxylate superplasticizer under low temperature conditions

A technology for synthesizing polycarboxylic acid and low temperature conditions, applied in the field of concrete admixtures, can solve the problems of long synthesis time, decreased initiation efficiency, low utilization rate of polyether, etc., and achieves stable and excellent performance, high initiation efficiency and high conversion rate. Effect

Active Publication Date: 2021-10-01
云南建投高分子材料有限公司 +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Synthesis of polycarboxylic acid at room temperature can be promoted and produced in large quantities by selecting a suitable initiator system, but there are still many problems in the practical application of low temperature polymerization, which will have a great impact on production in winter
When the temperature is too low, free radicals cannot be continuously generated, the double bonds of active monomers are opened slowly, and the initiation efficiency is greatly reduced, which leads to unreasonable molecular weight of the polymer, a large decrease in the conversion rate of monomers, and the inability of most monomers to complete polymerization. Low, long synthesis time; on the other hand, due to the instability of temperature, the molecular weight and molecular weight distribution of the polymer fluctuate greatly, and the application performance of the synthetic product is unstable

Method used

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  • Method for stably synthesizing polycarboxylate superplasticizer under low temperature conditions
  • Method for stably synthesizing polycarboxylate superplasticizer under low temperature conditions
  • Method for stably synthesizing polycarboxylate superplasticizer under low temperature conditions

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Under the condition of 5-20° C., 460 g of prenol polyoxyethylene ether with a molecular weight of 2400 and 360 g of water were added into a four-neck bottle reaction kettle and stirred to dissolve. Add 0.2g ferric oxide and ferrous oxide mixture (Fe 2 o 3 : FeO=1:3), then add 3g of ammonium persulfate. Mix 31g of acrylic acid and 57g of water to obtain liquid A. Mix 1.25g vitamin C and 2.2g mercaptopropionic acid with 65g water to obtain liquid B. Add liquid A and liquid B dropwise at the same time, liquid A is added dropwise for 150 minutes, and liquid B is added dropwise for 180 minutes. There is no need for heating or temperature control during the dropping process. After the dropwise addition, mature for 30 minutes, and then add 15 g of sodium hydroxide. Water is added to adjust the solid content, and the polycarboxylate superplasticizer with excellent slump retention performance can be obtained.

Embodiment 2

[0024] Under the condition of 5-20°C, add 420 g of methallyl alcohol polyoxyethylene ether with a molecular weight of 2400 and 380 g of water into a four-neck bottle reaction kettle and stir to dissolve. Add 0.2g ferric oxide to the reaction kettle, and then add 3.2g potassium persulfate. Mix 20g of acrylic acid and 55g of hydroxyethyl acrylate with 20g of water to obtain liquid A. Mix 0.6g of vitamin C and 1.9g of thioglycolic acid with 45g of water to obtain liquid B. Add liquid A and liquid B dropwise at the same time, liquid A is added dropwise for 120 minutes, and liquid B is added dropwise for 150 minutes. There is no need for heating or temperature control during the dropping process. After the dropwise addition, mature for 30 minutes, and then add 10 g of sodium hydroxide. Add water to adjust the solid content to obtain super slump polycarboxylate superplasticizer.

Embodiment 3

[0026] Under the condition of 5-25°C, add 400 g of ethylene glycol polyoxyethylene ether with a molecular weight of 3000 and 320 g of water into a four-neck bottle reaction kettle and stir to dissolve. Add 0.15g of rust to the reactor, and then add 4g of 30% hydrogen peroxide. Mix 35g of acrylic acid with 70g of water to obtain liquid A. Mix 1.0g vitamin C and 2.6g mercaptoethanol with 50g water to obtain liquid B. Add liquid A and liquid B dropwise at the same time, add liquid A dropwise for 60 minutes, add liquid B dropwise for 70 minutes, and control the temperature of the water bath not to exceed 30°C during the dropwise addition. After the dropwise addition, mature for 20 minutes, and then add 15 g of sodium hydroxide. Water is added to adjust the solid content, and a polycarboxylate superplasticizer with excellent comprehensive performance can be obtained.

[0027] Examples 4-7 are shown in Table 1.

[0028] Table 1 Example raw material combination table (unit / g)

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Abstract

The invention belongs to the field of building materials, particularly concrete admixtures, and specifically relates to a method for stably synthesizing a polycarboxylate water reducer under low temperature conditions; the preparation method comprises the following steps: 1) under low temperature, an unsaturated polyether macromonomer and water 2) Add iron oxide and oxidant to the reactor; 3) Add liquid A and liquid B dropwise at the same time, liquid A is an aqueous solution of unsaturated carboxylic acid and / or unsaturated ester, liquid B is a reducing agent and Chain transfer agent mixed aqueous solution, A solution is added dropwise for 60-150min, and B solution is added dropwise for 90-180min; 3) Add sodium hydroxide to adjust the pH after aging for 30min. The polycarboxylic acid synthesis of the present invention uses iron oxide as a catalyst, and the oxidant is put into a reaction kettle by adding in advance, the synthesis process does not need heating, the polyether utilization rate is high, and the polycarboxylic acid has stable performance. The synthesis method is environmentally friendly and efficient, and can be widely used in industry.

Description

technical field [0001] The invention belongs to the field of building materials, especially concrete admixtures, and in particular relates to a method for stably synthesizing a polycarboxylate water reducer under low temperature conditions. Background technique [0002] With the rapid development of high-performance concrete technology, polycarboxylate high-performance water reducer has become one of the indispensable components in the development of high-performance concrete. Due to the advantages of low dosage, high water reducing rate, good compatibility, and environmental protection, polycarboxylate high-performance water reducing agent has been widely used in major projects such as high-speed rail, water conservancy and hydropower, and nuclear power, and has gradually become a water reducing agent. Hotspots and directions of agent technology development. [0003] In terms of the synthesis of water reducers, normal temperature (20-35°C) and low temperature (5-20°C) synt...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F283/06C08F220/06C08F220/20C08F222/06C08F218/08C08F4/26C08F4/40C04B24/26C04B103/30
CPCC04B24/2605C04B24/2694C04B2103/302C08F4/26C08F4/40C08F283/065C08F220/06C08F220/20C08F222/06C08F218/08
Inventor 马敏超陈玉超饶烨梁丽敏余永益段志莹李震卢采梦陈绍伟吕文楠高荣贵闫成君孔令鑫
Owner 云南建投高分子材料有限公司
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