Search

CN-122010635-A - Cellulose coated urea slow-release fertilizer and preparation method thereof

CN122010635ACN 122010635 ACN122010635 ACN 122010635ACN-122010635-A

Abstract

The invention discloses a cellulose coated urea slow-release fertilizer and a preparation method thereof, belonging to the technical field of slow-release fertilizer preparation. The preparation method comprises the steps of mixing an adhesive, urea and water, granulating to obtain mixed particles, uniformly mixing a cellulose base material, a cross-linking agent, an auxiliary agent and water to obtain a coating precursor solution, mixing the coating precursor solution with the mixed particles, drying to obtain a coating body, dissolving the coating body and a surface modifier in a solvent, stirring for reacting, drying to obtain a modified body, and repeating the coating and modification steps for 1-3 times to obtain the modified body. The invention also discloses the cellulose coated urea slow release fertilizer prepared by the method. The cellulose coated urea slow-release fertilizer can effectively solve the problems of poor film forming property and poor urea slow-release property of the existing urea slow-release fertilizer, and has good practical value.

Inventors

  • WANG MEI
  • YANG WENHUA
  • TANG YURAN
  • PENG YUAN

Assignees

  • 内江师范学院

Dates

Publication Date
20260512
Application Date
20260313

Claims (10)

  1. 1. The preparation method of the cellulose coated urea slow release fertilizer is characterized by comprising the following steps of: (1) Mixing the adhesive, urea and water, and granulating to obtain mixed granules; (2) Uniformly mixing a cellulose base material, a cross-linking agent, an auxiliary agent and water to obtain a coating precursor liquid; (3) Mixing the coating precursor liquid with the mixed particles and drying to obtain a coating body; (4) The coating body and the surface modifier are dissolved in a solvent together for stirring reaction and drying to obtain a modified body; (5) Repeating the steps (3) - (4) for 1-3 times to obtain the cellulose coated urea slow release fertilizer.
  2. 2. The method for preparing a cellulose coated urea slow release fertilizer according to claim 1, wherein the binder in the step (1) is at least one of carboxymethyl cellulose, ethyl cellulose, hydroxypropyl cellulose and hydroxypropyl methyl cellulose.
  3. 3. The preparation method of the cellulose coated urea slow release fertilizer according to claim 1 or 2, which is characterized in that the mass ratio of urea to binder to water is 100 (0.5-5) (1-5), the granulation is carried out in an extrusion granulation or rotary granulation mode, and the diameter of the mixed particles is 3-5 mm.
  4. 4. The method for preparing the cellulose coated urea slow-release fertilizer according to claim 1, wherein the cellulose base material in the step (2) is at least one of carboxymethyl cellulose, hydroxypropyl methylcellulose and hydroxyethyl cellulose, the cross-linking agent is at least one of glutaraldehyde, glycerol triglycidyl ether, epichlorohydrin and formaldehyde, and the auxiliary agent is at least one of sodium hydroxide, potassium hydroxide, triethylamine, tributylamine, tetrabutylammonium bromide and polyethylene glycol 200.
  5. 5. The preparation method of the cellulose coated urea slow release fertilizer according to claim 1 or 4, wherein the mass ratio of the cellulose base material to the cross-linking agent to the auxiliary agent to the water is 100:2-10:0.5:500-1000.
  6. 6. The preparation method of the cellulose coated urea slow release fertilizer according to claim 1, wherein the mass of the coating precursor liquid in the step (3) is 5-10% of the mass of urea in the mixed particles.
  7. 7. The method for preparing the cellulose coated urea slow release fertilizer according to claim 1, wherein the drying temperature in the step (3) is 50-100 ℃ and the time is 10-30 min.
  8. 8. The method for preparing the cellulose coated urea slow-release fertilizer according to claim 1, wherein the surface modifier in the step (4) is at least one of octanoyl chloride, decanoyl chloride, lauroyl chloride, tetradecoyl chloride and oleoyl chloride, the solvent is petroleum ether, and the mass of the surface modifier is 0.1-1% of the mass of the mixed particles.
  9. 9. The preparation method of the cellulose coated urea slow release fertilizer according to claim 1, wherein the stirring reaction temperature in the step (4) is room temperature, the time is 30-120 min, the drying temperature is 60-90 ℃ and the time is 10-30 min.
  10. 10. The cellulose coated urea slow release fertilizer prepared by the preparation method of any one of claims 1-9.

Description

Cellulose coated urea slow-release fertilizer and preparation method thereof Technical Field The invention belongs to the technical field of slow release fertilizer preparation, and particularly relates to a cellulose coated urea slow release fertilizer and a preparation method thereof. Background Urea is used as a nitrogen fertilizer variety with the largest dosage in agricultural production, has the obvious advantage of high nitrogen content, but has too high dissolution rate after being applied into soil, so that more than 50% of nitrogen is lost through ammonia volatilization, nitrate nitrogen leaching, denitrification and other ways, the utilization rate of the fertilizer is low, the agricultural cost is increased, and a series of serious ecological environment problems such as water eutrophication, soil acidification and the like are also caused. In order to solve the problem, the slow release fertilizer technology has been developed, and the hydrophobic material is coated on the surface of the urea particles to delay the release of nutrients, so that the one-time fertilization can meet the demands of crops in the whole growth period. However, the existing coating materials are mainly divided into two types, namely inorganic coating materials such as sulfur, minerals and the like, wherein the problems of easy rupture and uncontrollable release of a film layer exist in the low cost, and synthetic high-molecular polymers such as polyurethane, polyethylene and the like, and the problems of excellent controlled release performance and difficult degradation in soil, so that the accumulation of microplastic and the degradation of ecological functions of soil can be caused by long-term application. In recent years, natural biological base materials represented by cellulose are paid attention to because of the characteristics of reproducibility, biodegradability and environmental friendliness, but the inherent strong hydrophilicity of cellulose causes the coating layer to easily swell when meeting water, so that the nutrient release rate is too fast to meet the long-acting slow release requirement, and meanwhile, the existing preparation process generally has technical bottlenecks such as uneven film structure, insufficient mechanical strength and the like. How to modify cellulose and prepare uniform coated slow release fertilizer, control the release rate of urea and realize the requirement of long-acting slow release is one of the research hot spots in the field at present. Disclosure of Invention The invention aims to solve the problems of poor film forming property and poor urea slow release property of the conventional urea slow release fertilizer. The technical scheme adopted for solving the technical problems is that the preparation method of the cellulose coated urea slow release fertilizer comprises the following steps: (1) Mixing the adhesive, urea and water, and granulating to obtain mixed granules; (2) Uniformly mixing a cellulose base material, a cross-linking agent, an auxiliary agent and water to obtain a coating precursor liquid; (3) Mixing the coating precursor liquid with the mixed particles and drying to obtain a coating body; (4) The coating body and the surface modifier are dissolved in a solvent together for stirring reaction and drying to obtain a modified body; (5) Repeating the steps (3) - (4) for 1-3 times to obtain the cellulose coated urea slow release fertilizer. The preparation method has the beneficial effects that in the preparation method, the cellulose adhesive is used as an adhesive and a coating main material of urea, has good water solubility and extremely high viscosity characteristics at low temperature, can form a physical interlayer to prevent urea release after absorbing water, the outer layer coating material mainly uses a cellulose substrate with good film forming property to ensure the continuity and integrity of a coating film structure, the urea is coated in the multilayer cellulose coating structure in an original form by constructing the multilayer cellulose coating structure and introducing crosslinking and surface modification treatment, the dissolution and release of the urea are realized by absorbing water in air and soil, the problems that the traditional urea fertilizer is low in utilization rate and easy to run off and the plastic coating material is difficult to degrade are effectively solved, specifically, the natural renewable cellulose is used as a substrate, a compact three-dimensional network coating layer is formed under the effect of a crosslinking agent, the release rate of the urea in the soil is remarkably delayed, so that the fertilizer efficiency is prolonged and the nitrogen loss is reduced, and meanwhile, the hydrophilic-hydrophobic equilibrium relationship of the surface of the cellulose-based coating material is adjusted by the surface modifier, so that the water absorption rate of the coating material is controlled under high humidity e