Preparation method of polycarboxylate water reducing agent

Abstract

The invention discloses a preparing method of polycarboxylate dehydragent, which comprises the following steps: dripping macromolecule of polyethylene glycol dimonomethyl ether (methyl) acrylate and micromolecule of (methyl) acrylate in the solvent to polymerize; adding alkaline compound; adjusting pH value at 9+-0.5; setting the molar rate of macromolecule and micromolecule at 1: 1-10; making the molecular weight of short chain between 600 and 800 corresponding to molecular weight of polyethylene glycol dimonomethyl ether; adopting water as solvent; controlling the reacting temperature at 70-100 Deg C for 2-8h; making the molecular weight of long chain as 1.5-8 times as short chain; possessing solid quantity in the copolymer system at 18-25%.

Description

technical field [0001] The invention relates to a concrete admixture, in particular to a synthesis method of a polycarboxylate water reducer. Background technique [0002] With the rapid development of the concrete industry, the use of concrete admixtures to improve the performance of concrete has attracted more and more attention. Polycarboxylate superplasticizer is a research hotspot at home and abroad in recent years. It has many unique advantages. For example, this superplasticizer can have relatively good compatibility with different cements; Concrete has good fluidity; it has low viscosity and relatively good slump retention at low water-cement ratio. [0003] The synthesis method of polycarboxylate superplasticizer has been reported in a large number of literatures, for example: [0004] Chinese invention patent CN1316398A discloses a preparation method of polycarboxylate concrete water reducing agent, the synthesis method is divided into two steps, the first step i...

AI Technical Summary

Problems solved by technology

[0006] These methods are complex and strict, especially organic solvents such as methyl ethyl ketone and toluene need to be used in the reaction, the cost is high, and it is easy to cause environmental pollution; while the chain transfer agent mercaptoethanol remains in the product, and the smell is unpleasant

[0007] Polyethylene glycol monomethyl ether is esterified with (meth)acrylic acid to obtain polyethylene glycol monomethyl ether (meth)acrylate macromolecules, and then copolymerized with (meth)acrylic acid small molecules to prepare Polycarboxylate water reducer has been reported, but its water reducing effect is not good, especially for different grades of cement, the consistency of water reducing rate is poor, and mercaptoethanol is used as chain transfer agent in the copolymerization reaction, which has an unpleasant smell