Preparation method of naphthalene-series water reducing agent

Abstract

The invention relates to a preparation method of a naphthalene-series water reducing agent. The method comprises the following steps: (1) methylnaphthalene and phenol are separately sulfonated, such that a sulfonated methylnaphthalene material and a p-hydroxybenzenesulfonic acid material are obtained; (2) the sulfonated methylnaphthalene material is subjected to a hydrolysis reaction; un-reacted methylnaphthalene or homologs thereof are removed through zeotropy; the rest of the sulfonated methylnaphthalene material enters a reaction in the step (3); (3) the sulfonated methylnaphthalene material obtained in the step (2) and the p-hydroxybenzenesulfonic acid material obtained in the step (1) are subjected to a condensation reaction with formaldehyde acidified with concentrated sulfuric acid, such that a condensed material is obtained; and (4) alkali liquid is added into the condensed material obtained in the step (3), such that a neutralization reaction is carried out, until the pH value is 7.5-9; and the naphthalene-series water reducing agent is obtained when the reaction is finished. The naphthalene-series water reducing agent provided by the invention has the excellent performances of good adaptability to cement, good concrete workability, high plasticity-maintaining performance, low concrete gradual loss, high water reducing rate, and the like. The preparation method has the advantages of simple process and easy-to-control reaction conditions. With the method, naphthalene-series water reducing agent production cost can be reduced.

Description

(1) Technical field [0001] The invention relates to a preparation method of a concrete admixture, in particular to a preparation method of a naphthalene-based water reducer. (2) Background technology [0002] Naphthalene-based water reducer is the largest and most widely used water reducer in China, with a market share of about 70%. Naphthalene-based superplasticizers are mature in production technology, easy to use, have little effect on setting time, relatively good adaptability to cement, good workability in concrete, and can be used in combination with other admixtures, especially for excess In terms of use, it is more predictable than other types of water reducing agents and has a wide customer base. It is often used to prepare high-fluidity, high-strength, high-performance concrete. However, naphthalene-based water reducers also have certain defects, and the slump of concrete simply mixed with naphthalene-based water-reducers loses quickly over time. [0003] Naphtha...

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Problems solved by technology

[0005] One of the purposes of the present invention is to provide a new method for preparing a naphthalene-based water reducer, which not only has good adaptability to cement, good workability of concrete, etc., but also overcomes the problems of the prior art. The water reducing agent has a serious loss of concrete slump over time, and the high air content leads to low concrete strength; and its preparation method is simple, the reaction conditions are easy to control, and it can also reduce the production cost of naphthalene-based water reducing agent

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