Method for preparing ammonium-sodium polyacrylate dispersant

Abstract

The invention discloses a method for preparing an ammonium-sodium polyacrylate dispersant. The preparation method comprises the following steps of: 1, in part by weight, dissolving 20 to 40 parts of a PI control agent in 100 parts of deionized water, uniformly mixing and heating the mixed solution to 50 to 70 DEG C; 2, at normal temperature, adding 5 to 15 parts of initiator into 100 parts of deionized water to prepare the solution, fully dissolving 90 to 120 parts of acrylic acid in the solution to prepare the mixed solution; 3, adding the mixed solution into the water bath obtained by the step 1 to perform polyreaction, and after the mixed solution is added, keeping the water bath to between 60 and 70 DEG C for reaction for 3+ / -0.5 hours, wherein the temperature of the water bath is less than or equal to 75 DEG C during addition; and 4, after reaction, adding a neutralizer dropwise until a PH value of the solution is 7.0 to 7.5, and finally obtaining the dispersant. When the ammonium-sodium polyacrylate is used, the dosage of the ammonium-sodium polyacrylate is 0.2 to 0.3 percent based on the weight of calcium carbonate.

Description

technical field [0001] The invention relates to a dispersant used when ground calcium carbonate is ground, in particular to a preparation method of a sodium ammonium polyacrylate dispersant. Background technique [0002] With the introduction of high-concentration coating machines and the development of coated paper, the demand for high-quality slurry ground calcium carbonate is increasing. As a necessary additive for the production of slurry calcium carbonate, the demand for dispersants is also increasing. . [0003] Dispersants play a key role in the grinding process of slurry calcium. The process of slurry calcium preparation is to suspend calcium carbonate particles in water, but the particles must be dispersed due to van der Waals gravity. There are many inorganic dispersants in use. Disadvantages, such as relatively low solid content of dispersion liquid, easy hydrolysis to cause pigment flocculation, poor dispersion stability over time, etc., thus further embodying t...

AI Technical Summary

Problems solved by technology

However, the polymerization reaction of acrylic acid is an exothermic reaction. If a large amount of acrylic acid is polymerized at the same time, a large amount of reaction heat will be generated. If this part of the heat cannot be taken away by the external system in time, it will inevitably lead to an increase in the temperature of the reaction system itself, thereby further accelerating the reaction. , continue to generate more heat, so that the phenomenon of bursting occurs

Therefore, the reaction process is difficult to control, and there is often an incomplete reaction due to the violent reaction, resulting in low polymerization conversion; and the produced dispersant product has a wide range of molecular weight and high molecular weight distribution, resulting in poor dispersion effect

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