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Preparation method of composite coated water retaining and slowly-releasing urea

A slow-release urea and coating technology, which is applied in the field of preparation of composite-coated water-retaining slow-release urea, can solve the problems of water absorption, poor slow-release performance, salt-intolerant water-retaining agent, easy moisture absorption of film materials, etc. Utilization, easy storage and transportation, reduced evaporation effect

Active Publication Date: 2016-02-10
ZHONGKAI UNIV OF AGRI & ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The current preparation process and fertilizer performance of coated water-retaining slow-release fertilizers mainly have the following problems: multiple coatings, complex process; part of the process is reverse-phase polymerization film-forming process, a large amount of organic solvents are used in the polymerization process, causing environmental pollution ; The water-retaining agent is not resistant to salt, and has poor water absorption and slow-release performance; during storage, transportation and use, the membrane material is easy to absorb moisture and fall off

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] The preparation method of the compound coated water-retaining slow-release urea of ​​this embodiment, the method used comprises the following steps:

[0032] (1) Weigh 300g of acrylic acid monomer into the reactor, stir evenly, slowly add 207g of ammonia water, so that the neutralization degree of acrylic acid reaches 80%; then add 200g of acrylamide monomer, 0.5g of N,N-methylenebis Acrylamide, after fully dissolving and mixing, add 8g of ammonium persulfate, react at 80°C for 1-2 hours, cut the reaction product into pieces, dry, pulverize, and sieve to obtain a powdery water retaining agent with a particle size of less than 0.075mm.

[0033] (2) 468g of 2% chitosan solution and 32g of 10% polyvinyl alcohol solution were fully stirred and mixed, and 1ml of 40% glutaraldehyde was added, stirred and mixed to obtain a coating solution.

[0034] (3) Weigh 5kg of urea and put it into the coating equipment. At the same time, heat the reaction material with hot air, keep the ...

Embodiment 2

[0037] The preparation method of the composite coating water-retaining slow-release fertilizer of the present embodiment, the method used comprises the following steps:

[0038] (1) Weigh 600g of acrylic acid monomer into the reactor, stir evenly, slowly add 453g of ammonia water, so that the neutralization degree of acrylic acid reaches 80%; then add 400g of 2-acrylamido-2-methylpropanesulfonic acid monomer in turn , 1.2g N,N-methylenebisacrylamide, fully dissolved and mixed, add 20g ammonium persulfate, 80℃, react for 1~2h, cut the reaction product into pieces, dry, crush, and sieve to obtain a particle size of less than 0.075 mm powdered water retaining agent.

[0039] (2) 468g of 2% chitosan solution and 32g of 10% polyvinyl alcohol solution were fully stirred and mixed, and 1.2ml of 40% glyoxal was added, stirred and mixed to obtain a coating solution.

[0040] (3) Weigh 5kg of urea and put it into the coating equipment. At the same time, heat the reaction material with ...

Embodiment 3

[0043] The preparation method of the compound coated water-retaining slow-release urea of ​​this embodiment, the method used comprises the following steps:

[0044](1) Weigh 540g of acrylic acid monomer and add it to the reactor, stir evenly, slowly add 408g of ammonia water, so that the neutralization degree of acrylic acid reaches 80%; then add 360g of acrylamide monomer, 100g of 2-acrylamide-2-methyl Propanesulfonic acid monomer, 1.2g N,N-methylenebisacrylamide, after fully dissolved and mixed, add 20g ammonium persulfate, 80℃, react for 1~2h, cut the reaction product into pieces, dry, pulverize, Sieve to obtain a powdery water-retaining agent with a particle size of less than 0.075 mm.

[0045] (2) 468g of 2% chitosan solution and 32g of 10% polyvinyl alcohol solution were fully stirred and mixed, and 1.2ml of 40% glyoxal was added, stirred and mixed to obtain a coating solution.

[0046] (3) Weigh 5kg of urea and put it into the coating equipment. At the same time, heat ...

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Abstract

The invention provides a preparation method of composite envelope water retaining and slowly-releasing urea. The water retaining and slowly-releasing urea of a dual-layer film structure is formed with large granular urea as a kernel, a chitosan-polyving akohol composite film as an inner coating layer and a water-retaining agent as an outer coating layer, and the water retaining and slowly-releasing urea has excellent water retaining and nutrient slowly releasing properties. The method is characterized by comprising the steps that the large granular urea with the diameter of 2-5 mm is put into a coating device, the urea rolls in the coating device and is heated to be 80-100 DEG C, chitosan-polyving akohol coating fluid is sprayed to the surface of the urea, the water-retaining agent of the grain size of 0.075 mm is added, epoxy chloropropane with the concentration of 0.5% is sprayed by a spraying gun with the intensity of pressure larger than or equal to 0.4 MPa for the surface cross-linking reaction, and finished fertilizers are obtained after drying is performed. The water retaining and slowly-releasing urea is simple in production process, low in investment cost, and easy in industrial production. No organic solvent is used in the production process, and secondary pollution caused by using organic solvents is avoided accordingly.

Description

technical field [0001] The invention relates to a preparation method of composite coated water-retaining slow-release urea. Background technique [0002] my country is a large agricultural country. Chemical fertilizers play an important role in agricultural production. They are the basis for increasing grain production and the material guarantee for sustainable agricultural development. At present, the fertilizers used in agriculture are mainly high water-soluble fertilizers, which have high water solubility and quick-acting nutrients. But the disadvantages are fast nutrient release, short validity period, uncoordinated nutrient release and crop nutrient absorption, easy loss or fixation of fertilizer nutrients, and low utilization rate. A large number of studies have shown that the seasonal utilization rate of my country's farmland chemical fertilizers is only 30-50% for nitrogen fertilizers, 10-20% for phosphorus fertilizers, and 35-50% for potassium fertilizers, which ar...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C05G3/04C05G3/08C05G3/80C05G3/90
Inventor 黄帮裕杜建军王新爱李永胜
Owner ZHONGKAI UNIV OF AGRI & ENG
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