Method for preparing high-efficiency water-reducing agent of poly-carboxylic acid

Abstract

The invention discloses a preparation method for a polycarboxylate high-performance water reducer, comprising the following steps: based on weight proportion, mixing 5-50% of unsaturated carboxylic acid, a derivative a of the unsaturated carboxylic acid, 45-95% of polyoxyethylene vinyl propionate ester, a derivative b of the polyoxyethylene vinyl propionate ester, as well as 0-30% of propyl sulfonate c to prepare a mixed monomer solution; then adding the initiator which takes up 0.5-15% of the total weight of the mixed monomer solution, and the chain transfer agent which takes up 0-15% of thetotal weight of the mixed monomer solution into the mixed monomer solution so as to prepare the polycarboxylate high-performance water reducer through binary or ternary copolymerization. The polycarboxylate high-performance water reducer disclosed in the invention can be widely applied to grout, mortar, concrete, gypsum and coal-water slurry, so that the mixed material can have higher mobility tosignificantly reduce the actual water consumption in the mixing process and effectively improve the concrete strength and durability, thereby showing the advantages of low mixing amount, high dispersion and high slump retaining performance.

Description

technical field [0001] The invention relates to a preparation method of a polycarboxylic acid high-efficiency water reducer. Background technique [0002] The early water reducing agents were mostly lignin sulfonate, naphthalene sulfonate formaldehyde condensate NSF, melamine sulfonate formaldehyde condensate MSF, aliphatic sulfamic acid ASPF, etc., which mainly played the role of reducing water, but There are problems such as high dosage, poor workability, poor adaptability, and large loss of concrete over time. If the dosage is too high, it will lead to poor water retention, severe segregation and bleeding, etc., making the concrete sticky, poor product stability, and difficult to modify. Simultaneous production and use all have pollution to the environment, use formaldehyde in its manufacturing process, can cause environmental pollution, slump loss through time is big and produce retardation; The naphthalene that uses is considered to be possible carcinogen, thereby has ...

AI Technical Summary

Problems solved by technology

[0004] At home and abroad and in the literature, it is mentioned that the polymerization method for preparing polymers generally adopts a two-step method or a grafting method. The two-step method is more complicated to prepare the production process, and the reaction conditions are harsher and difficult to control, especially the preparation of the first step product. The obtained product contains too many impurities, which greatly affects the second-step polymerization reaction

Long production time, many restrictions, low efficiency, complex influencing factors, difficult to control the purity of intermediates, and some of the above preparation methods are carried out in organic solvents, which is not conducive to clean production and environmental protection

It also complicates the process, increases the cost, and brings inconvenience to production and use.

The polycarboxylate superplasticizer prepared by the two-step method has relatively large fluctuations in water reducing rate, poor adaptability to cement, poor compatibility with other admixtures, and poor temperature stability