Method for preparing resin type water-retaining preparation

Abstract

The invention discloses a preparation method of a resin-type water-retaining agent. Starch, acrylic acid and acrylamide are used as raw materials, a redox system formed by potassium persulfate-sodium bisulfite is used as an initiator, and N, N'-methylene The specific steps are as follows: 1) first gelatinize the starch in the reactor, then neutralize the acrylic acid with potassium hydroxide, cool to room temperature and pour it together with the acrylamide aqueous solution Put into the reactor and mix with the starch after gelatinization; 2) add initiator, cross-linking agent, in N 2 Stirring at a constant temperature under protection until the end of the polymerization reaction; 3) adjusting the pH to neutral with lye, and washing, filtering, drying and pulverizing the grafted product to obtain a white granular resin product. The water-retaining agent obtained by the invention has fast water absorption rate and high water absorption rate, and replaces traditional sodium hydroxide with potassium hydroxide, which can prevent excessive sodium ions from destroying soil structure in agricultural applications, and can provide potassium fertilizer for crops at the same time.

Description

technical field [0001] The invention relates to water-saving and water-retaining technology, in particular to a method for preparing a resin-type water-retaining agent. Background technique [0002] In recent years, due to the drought and lack of rainfall in most parts of the north, the crisis of agricultural water use has been intensified. The development of water-saving irrigation and dryland agricultural water-saving and water-saving technologies centered on making full use of natural precipitation has become an inevitable choice for sustainable agricultural development. Among them, the use of soil water-retaining agents to save water and increase production is an effective way and method of water-saving in modern agriculture. . [0003] There are many kinds of superabsorbent resin materials produced all over the world, and starch is the main material in the United States, Europe and China. This is because starch is a cheap, easy-to-obtain natural polymer raw material, ...

AI Technical Summary

Problems solved by technology

[0004] At present, most water-absorbent resins are synthesized by binary copolymerization. For example, US4134863, US3981100, and CN86104111 use acrylonitrile as the acrylic monomer. Their disadvantage is that the -CN contained in the synthesized resin must be converted into hydrophilic Only the water group has water absorption, and the process is complicated

Another example is that the special public clear 54-37188 and the special public clear 58-25160 use starch grafted acrylic acid. Their common feature is that the absorption rate of distilled water is high, but the absorption rate of salt water is low. This is because the -COOH of acrylic acid is ionic. The effect of electrolytes is very large

However, US4921904 and EP347241 are binary graft copolymers of starch and acrylamide. Since the amide group is non-ionic, it is less affected by the electrolyte, so that the salt water absorption rate of this type of resin is increased, but the overall ability to absorb distilled water is reduced.

In addition, the above patents use sodium hydroxide during hydrolysis and neutralization, and sodium ions will destroy the structure of the soil after entering the soil, resulting in soil compaction