Preparation method of water retaining agent

Abstract

The invention discloses a preparation method of a water retaining agent. The preparation method comprises the following steps: carrying out an aqueous phase radical polymerization reaction on unsaturated amide micro-monomers, unsaturated sulphonic acid micro-monomers and unsaturated polyether macromers or unsaturated ester macromonomers under the coaction of an oxidation-reduction system composed of an initiator and a reducing agent to obtain a copolymerization product, regulating the pH value to 6-7 after the reaction, and adding water to obtain the water retaining agent with mass concentration of 1-60%. The preparation method disclosed by the invention is used for adjusting the product properties by controlling the monomer proportion, the temperature and the dosage of the initiator and the reducing agent, the reaction speed is high, the efficiency is high, no organic solvent is used, no toxin or pollution is generated, and the operation is simple. The unsaturated macromonomers are introduced into the prepared concrete/mortar water retaining agent to ensure excellent water retaining property and obviously perfect such stirring states of the concrete/mortar as bleeding/separation and the like without generating such adverse effects as strength and the like, meanwhile, the water retaining agent can be compounded with a polycarboxylic acid water reducing agent at any proportion to ensure good intermiscibility. The product performance is stable.

Description

technical field [0001] The invention relates to the technical field of a water-retaining agent for concrete / mortar, in particular to a preparation method of a water-retaining agent for concrete / mortar by radical polymerization. Background technique [0002] In recent years, most areas have gradually canceled the use of other high-efficiency water reducers such as naphthalene and aliphatic. Although the performance of polycarboxylate high-performance water reducer has been greatly improved with the joint efforts of raw material manufacturers and manufacturers, there are still many technical difficulties to be solved in its practical application, especially for the mineral admixture used in concrete. Sensitivity to quality fluctuations of aggregates and coarse and fine aggregates. Compared with naphthalene-based and aliphatic superplasticizers, polycarboxylate high-performance superplasticizers are more sensitive to the mud content of aggregates. When the mud content of sand ...

AI Technical Summary

Problems solved by technology

Due to the high water-reducing properties of polycarboxylate high-performance water-reducing agent and its sensitivity to materials, it will either cause the concrete mixture to separate, segregate, bleed, and bleed, making the concrete mixture lose its workability; The slump loss of the material is serious, and the long-distance and pipeline transportation of concrete cannot be guaranteed.

[0003] At present, sand and gravel resources are tight, and the supply of river sand is limited. Many inferior sand and gravel are of poor quality and high in mud content, and they are put into use without washing with clean water, resulting in many quality problems during the construction process.

Most water retaining agents such as soluble polymers and cellulose series can effectively reduce bleeding on the one hand, but on the other hand reduce the slump expansion of concrete / mortar, increase water demand, and need to add more Many water reducers are used to maintain the required slump, and the slow dissolution rate is not compatible with polycarboxylate water reducers, which increases the difficulty of construction and significantly limits its application

Existing water-retaining agents such as cellulose ether reduce bleeding while reducing slump, making construction more difficult, expensive, and low in market acceptance

Images