Manufacturing method of hygroscopic resin with low residual monomer content

Abstract

The invention discloses a powdery water-insoluble hygroscopic resin with a low residual monomer content, which can absorb water, urine or blood. The manufacturing method of the hygroscopic resin comprises the following steps of: 1, adding a cross-linking agent to obtain a water solution containing acid radical monomer, which is more than 50mole% in neutralization degree, wherein the acid radical monomer is selected from acrylic acid, methacrylic acid, 2-acrylamide-2-methylpropanesulfonic acid(AMPS) or the mixture thereof; 2, adding an initiator into the monomer solution with the cross-linking agent and retaining the solution on a belt-type reactor; 3, heating two lower sides of the belt; 4, drying, crushing and screening the product under a hot air with a temperature of 100-250 DEG C; 5, coating the cross-linking agent on the surface; 6, heating the surface under a temperature of 80-230 DEG C; and 7, adding inert inorganic salt powder. The manufacturing method can improve the reactivity of the monomers on two sides of the belt so as to further improve the quality of the hygroscopic resin, and especially can obviously reduce the content of the residual monomer.

Description

technical field [0001] The present invention relates to a method for producing water-absorbent resin, which has the characteristic of low residual monomer content. [0002] Water-absorbent resin has a strong water-retaining power, can absorb water of a hundred times or even a thousand times its own weight, and can swell after absorbing water, and maintain a non-flowing state, even if pressure is applied, it will not leak, and the absorbed water can be Slowly released in the atmosphere. Due to the above characteristics, it was first used as a soil water retaining agent in agriculture and forestry. In recent years, due to considerable progress in the production technology of superabsorbent resin, it is also widely used in sanitary products such as diapers, adult incontinence products and women's hygiene products. water-absorbing agent and fresh-keeping applications for food preservation, etc. Background technique [0003] The component materials of the water-absorbent resin ...

AI Technical Summary

Problems solved by technology

[0005] The water-absorbent resin is an insoluble hydrophilic polymer, and the resin has a uniform bridging structure inside. Generally, in order to improve the quality, such as: increase the absorption rate, increase the colloid strength, improve the anti-caking property, liquid permeability, etc., will Further bridging is carried out on the surface of the resin. This surface cross-linking treatment uses a multi-functional cross-linking agent that can react with acid groups. Many patents have been proposed before; such as: dispersing super absorbent resin and cross-linking. The linking agent is subjected to surface cross-linking treatment in an organic solvent (JP-A-56-131608, JP-A-57-44627, JP-A-58-42602, JP-A58-117222), and the cross-linked Agent and cross-linking agent solution are mixed into superabsorbent resin treatment (JP-A60-163956, JP-A-60-255814), after adding cross-linking agent, steam treatment (JP-A-1-113406), using organic solvent, Surface treatment with water and polyalcohol (JP-A-63-270741, JP-A-64-50707, JP-A-1-292004), use of organic solution, water, ether (ether) compound (JP-A-2 -153903), etc.; although these surface treatment methods can increase the absorption rate and increase the water absorption rate under pressure, they will cause excessive reduction in retention and reduce the performance of practical applications.