A water-reducing and slump-preserving polycarboxylate water-reducer and its preparation method

Abstract

The invention discloses a water-reducing slump-retaining type polycarboxylic acid water reducing agent and a preparing method thereof. The water-reducing slump-retaining type polycarboxylic acid water reducing agent has the pH of 6.0-7.0 and comprises the following raw materials in parts by weight: 190-200 parts of methyl-2-buten-1-ol polyoxyethylene ether with the molecular weight of 600-3000, 15-25 parts of acrylic acid, 1-5 parts of hydroxyalkyl acrylate, 0.1-3 parts of unsaturated phosphate, 0.5-5 parts of unsaturated alcohol ether, 1.0-3.5 parts of an oxidant, 0.1-2 parts of a reductant, 0.1-2 parts of sodium formaldehyde sulfoxylate, 0.5-2.5 parts of a chain transfer agent, 325 parts of water, and a proper amount of a caustic soda liquid with the mass concentration of 30-32%. The water-reducing slump-retaining type polycarboxylic acid water reducing agent has the advantages of high content of effective components, good dispersion and excellent performance; and the preparation method adopts a room temperature process and a composite initiation system, has the appropriate reaction temperature of 5-40 DEG C, has no need of heating, makes the production more convenient and the cost lower, saves energy and protects the environment.

Description

technical field [0001] The invention belongs to the technical field of building materials, and in particular relates to a water-reducing and slump-preserving polycarboxylate water-reducer and a preparation method thereof. Background technique [0002] Compared with the first-generation lignosulfonate ordinary water-reducer and the second-generation naphthalene-based high-efficiency water-reducer, the polycarboxylate-based high-performance water-reducer has low dosage, high water-reducing rate, high workability, and high retention. It has a series of outstanding performance characteristics such as slump, high durability, low shrinkage, strong settable molecular structure and performance, high economy and environmental protection. It is used in key projects such as water conservancy, hydropower, bridges, high-speed railways and expressways And ordinary civil construction projects have been widely used. [0003] With the rapid increase in the use of ether polycarboxylate super...

AI Technical Summary

Problems solved by technology

The adaptability of concrete and admixtures is mainly reflected in the poor workability of concrete mixtures, large loss of slump over time, and delayed bleeding. In order to solve these problems, the following two solutions are generally adopted: (1) Add more slump retaining agent, coagulant, thickener and other additives that can improve performance when compounding polycarboxylate ether water reducer. Although this method can solve the problem of large slump loss, it is also It will bring high cost and subsequent setting time and strength problems; (2) use ester polycarboxylate water reducer to improve the slump retention and workability of concrete, but the production process of ester is complicated and the reaction temperature is high , long production cycle, high energy consumption and high cost

[0004] At present, ether polycarboxylate water reducers have achieved certain results in water reduction and slump protection, such as CN104261719 A with polyether macromers, unsaturated acid monomers, unsaturated phosphate monomers, chain transfer agents, Initiator and water are used as raw materials. Add dropwise for 4-6 hours at 40-80°C and keep warm for 2 hours to prepare a polycarboxylate water reducer with a phosphate ester structure. However, this patent uses a heating system and requires high equipment. And the synthesis time is long, the energy consumption is large, and the cost is high; CN 102515618 A uses unsaturated polyoxyethylene ether, acrylic acid, acrylate monomers, crosslinking monomers, chain transfer agents, initiators and water as raw materials, Under the condition of 80-90°C, react for 4-7 hours to prepare the slow-release slump-proof polycarboxylate superplasticizer, but this patent uses a heating system, which consumes a lot of energy, and the amount of superplasticizer is high, so the cost of use is high

[0005] To sum up, in the preparation of water-reducing and slump-preserving and good workability ether polycarboxylate superplasticizers, there are mainly high requirements for equipment in the heating process, high energy consumption, high cost and various performances. Problems that cannot be satisfied at the same time

Images