Preparation method of polycarboxylate water reducer containing complexing anti-mud structure

Abstract

The invention relates to the technical field of building materials, and particularly relates to a preparation method of a polycarboxylate water reducer containing a complexing anti-mud structure. The preparation method comprises the following steps: (1) uniformly mixing an unsaturated polyether macromonomer, an unsaturated acid monomer, an unsaturated halogen monomer, a chain transfer agent and an initiator, and carrying out a reaction at 70-90 DEG C for 2-3 hours; and (2) adding an unsaturated phosphate monomer into the reaction system, and carrying out a reaction at 80-110 DEG C for 4-6 hours to obtain the polycarboxylate water reducer containing the complexing anti-mud structure, wherein the weight ratio of the unsaturated polyether macromonomer to the unsaturated acid monomer to the unsaturated phosphate monomer to the unsaturated halogen monomer to the chain transfer agent to the initiator is (28-36):(1.3-4):(2.5-6):(1.5-4):(0.2-0.5):(0.1-0.6). The preparation method provided by the invention provides the polycarboxylate water reducer with good water reducing rate, slump retaining property and mud resistance.

Description

Technical field [0001] The invention relates to the technical field of building materials, in particular to a preparation method of a polycarboxylate water-reducing agent containing a complex mud-resistant structure. Background technique [0002] Polycarboxylate water-reducing agent (PCE) is more and more widely used in concrete engineering because of its excellent properties such as high water reducing rate, good slump retention, low dosage, strong molecular structure adjustment and green environmental protection. . However, compared with naphthalene-based and sulfamate-based water-reducing agents, the water-reducing rate and slump retention of polycarboxylic acid water-reducing agents are more sensitive to the mud content of sand and gravel. With the rapid development of the construction industry and the requirements of national environmental protection policies, high-quality sand and gravel resources are gradually depleted, and the sand and gravel resources in various places ...

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Problems solved by technology

[0004] Chinese patent document CN104261719A discloses a polycarboxylate water-reducer, the general structural formula of the polycarboxylate water-reducer molecule is composed of three parts: unsaturated carboxylic acid monomer, unsaturated phosphate monomer and polyether monomer There is no carboxyl group on the two carbon atoms of the disclosed unsaturated phosphate monomer, so the content of carboxyl group in the water reducer is low, and the slump retention ability in cement cannot achieve the best effect

However, due to the unsatisfactory unsaturated phosphate structure of the target product, the yield of unsaturated phosphate monoester is low, accompanied by the formation of diester and triester; at the same time, the phosphate group in the unsaturated phosphate monomer has a certain chain The transfer effect directly participates in the copolymerization reaction of the superplasticizer, which affects the structure of the superplasticizer, resulting in the inability to accurately control the molecular weight

[0006] Chinese patent document CN 106008853A discloses a preparation method of an anti-mud slump-containing phosphate-based polycarboxylate water-reducer, which consists of halogen-containing unsaturated monomers, unsaturated acid small monomers, unsaturated polymer Under the action of initiator, reducing agent and chain transfer agent, ether macromonomer or unsaturated ester macromonomer can prepare halogen-containing polycarboxylate superplasticizer prepolymer, and the prepolymer is combined with alkyl phosphate React at 80-150°C to obtain polycarboxylate superplasticizers containing phosphate groups, but the use of alkyl phosphate diesters and triesters may cause crosslinking and explosion in the copolymerization reaction and affect the structure of the superplasticizer , the used alkyl phosphate monoester will also cause the above situation due to the low purity, and the redox initiation system used in this invention may react with oxidative unsaturated halogen monomers, affecting the structure and produce a large number of by-products

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