US 10,865,161 B2 · Water-absorbing and water-retaining multi-nutrient biodegradable polymeric slow/controlled release fertilizer having a semi-interpenetrating network structure

Abstract

This disclosure relates to water-absorbing and slow/controlled release fertilizer, in particular to a water-absorbing and water-retaining multi-nutrient biodegradable polymeric slow/controlled release fertilizer having a semi-interpenetrating network structure, and preparation methods thereof. The method can comprises the steps of: reacting formaldehyde with urea to obtain a hydroxymethyl urea solution; adding acrylic acid and acrylamide monomers into another reactor, and adding a KOH solution to adjust the neutralization degree of acrylic acid, then adding one of inorganic clay, pretreated crop straw or cellulose, then adding initiator, monopotassium phosphate and the prepared hydroxymethyl urea solution sequentially; allowing to react at temperature after being mixed uniformly to obtain a viscous product; and granulating the viscous product and oven drying the same to obtain the fertilizer. The fertilizer prepared according to the present invention has strong water-absorbing and water-retaining capacity, and an excellent slow release performance for nitrogen, phosphorus and potassium contained as nutrients.

Claims11

Dependent claims

A water-absorbing and water-retaining multi-nutrient biodegradable polymeric slow/controlled release fertilizer having a semi-interpenetrating network structure, wherein the fertilizer comprises a high polymer having a semi-interpenetrating network structure, said semi-interpenetrating network structure of the high polymer being such that a polymeric slow/controlled release fertilizer (PRF) molecular chain is interposed in a composite water-absorbing resin network;

wherein said composite water-absorbing resin is of a three-dimensional spatial network structure formed by graft copolymerization of acrylic acid and acrylamide with inorganic clay or pretreated crop straw or cellulose under the action of an initiator and a crosslinking agent,
wherein the PRF is the reaction product of hydroxymethyl urea and monopotassium phosphate, and
wherein the semi-interpenetrating network structure is formed through simultaneous preparation of the composite water-absorbing resin and PRF in one reaction system.

A method for preparing a water-absorbing and water-retaining multi-nutrient biodegradable polymeric slow/controlled release fertilizer having a semi-interpenetrating network structure, wherein said method comprises the steps of:

(1) adding formaldehyde and urea respectively into a first reactor, adjusting the resultant system to pH=8 with a 5% KOH solution, and reacting the same at 40° C. for 2 h to obtain a hydroxymethyl urea solution;
(2) adding acrylic acid and acrylamide into a second reactor, and adding a 20 mass % KOH solution to adjust the neutralization degree of acrylic acid monomer to 20%-100%;
adding inorganic clay, pretreated crop straw or cellulose;
and then adding monopotassium phosphate, an initiator and the hydroxymethyl urea solution prepared in step (1) sequentially, mixing them under an ice bath for 30 min, warming the resultant mixture to 55° C. and then reacting the same under an atmosphere of nitrogen for 4 h to obtain a viscous product;
and
(3) granulating the obtained viscous product and oven drying the same to obtain a water-absorbing and water-retaining multi-nutrient biodegradable polymeric slow/controlled release fertilizer having a semi-interpenetrating network structure.

3 more elements

Dependencies are inferred from the claim text.

Water-absorbing and water-retaining multi-nutrient biodegradable polymeric slow/controlled release fertilizer having a semi-interpenetrating network structure

Life of this patent

Water-absorbing and water-retaining multi-nutrient biodegradable polymeric slow/controlled release fertilizer having a semi-interpenetrating network structure

Life of this patent

Abstract

Claims11