Preparation method of oil-based polyurethane slow-release nitrogen fertilizer

Abstract

The invention discloses a preparation method of oil-based polyurethane slow-release nitrogen fertilizer, and belongs to the technical field of non-isocyanate polyurethane slow-release fertilizer. Theslow-release nitrogen fertilizer comprises a granular urea fertilizer core and a polyurethane film coating the surface of the fertilizer core. The preparation method mainly comprises the following steps: firstly, carrying out alcoholysis reaction, namely taking a certain amount of urea particles and castor oil, carrying out alcoholysis reaction under the action of a catalyst, forming uniformly distributed cyclic carbonate intermediate products on the surfaces of the urea particles in the process, separating out solid particles after the reaction is finished, adding polyamine, carrying out polymerization reaction, removing excessive reactants after the reaction, and finally drying to obtain the polyurethane coated slow-release nitrogen fertilizer. The urea particles are used as reactants and directly subjected to alcoholysis polymerization to form a film on the surfaces of the urea particles, and the method has the advantages of low raw material cost, easiness in operation of the preparation method, controllable nitrogen fertilizer slow release time and the like.

Description

technical field

[0001] The invention belongs to the technical field of non-isocyanate polyurethane slow-release fertilizers, and in particular relates to a preparation method of oil-based polyurethane slow-release nitrogen fertilizers. Background technique

[0002] my country is a large agricultural country, and chemical fertilizers play an important role in agricultural production. However, the effective nutrient utilization rate of chemical fertilizers in my country is not high, the waste of chemical fertilizers is large, and the actual absorption of crops is very small, which not only causes serious pollution of soil and water bodies, but also leads to a huge waste of energy and financial resources.

[0003] The emergence of coated fertilizers has effectively alleviated this problem. Coated fertilizer is a kind of slow / controlled release fertilizer that has developed rapidly in recent years. It uses water-soluble fertilizer particles as the core, and low water-soluble or...

Examples

Embodiment 1

[0036] Weigh 25 parts of large particle urea, 1.5 parts of ZnO (urea precipitation method) catalyst and 25 parts of castor oil in a flask, heat it to a reaction temperature of 70 °C, and feed inert gas N 2 , the flow rate was controlled at 100mL / min, and the reaction was carried out for 5h without stirring. Subsequently, the grafted urea was collected, placed in a beaker, 12.5 parts of ethylenediamine was added, and the polymerization reaction was carried out at room temperature (25°C). The reaction time was 2h. The coated urea was taken out and dried naturally overnight, and finally dried at 40°C for 24h. , to obtain polyurethane-coated urea slow-release fertilizer.

[0037] Slow-release performance test: use p-dimethylaminobenzaldehyde color spectrophotometry to detect the content of urea in the aqueous solution of polyurethane slow-release nitrogen fertilizer, and then know the slow-release performance of the fertilizer. The method is as follows: Take 5.00g of polyurethane...

Embodiment 2

[0039] Weigh 25 parts of large particle urea, 1.5 parts of ZnO (roasted zinc nitrate) catalyst and 25 parts of castor oil in a flask, heat it to a reaction temperature of 70 ° C, and feed inert gas N 2 , the flow rate was controlled at 100mL / min, and the reaction was carried out for 5h without stirring. Subsequently, the grafted urea was collected, placed in a beaker, 12.5 parts of ethylenediamine was added, and the polymerization reaction was carried out at room temperature. The reaction time was 2 hours. The coated urea was taken out and dried naturally overnight, and finally dried at 40°C for 24 hours to obtain polyurethane coated Cover with urea slow-release fertilizer.

[0040] Performance testing method is as embodiment 1

Embodiment 3

[0042]Weigh 25 parts of large particle urea, 1.5 parts of ZnO (roasted zinc oxalate) catalyst and 25 parts of castor oil in a flask, heat to the reaction temperature of 70 ° C, and pass inert gas N 2 , the flow rate was controlled at 100mL / min, and the reaction was carried out for 5h without stirring. Subsequently, the grafted urea was collected, placed in a beaker, 12.5 parts of ethylenediamine was added, and the polymerization reaction was carried out at room temperature. The reaction time was 2 hours. The coated urea was taken out and dried naturally overnight, and finally dried at 40°C for 24 hours to obtain polyurethane coated Cover with urea slow-release fertilizer.

[0043] Performance testing method is as embodiment 1

technical field

[0001] The invention belongs to the technical field of non-isocyanate polyurethane slow-release fertilizers, and in particular relates to a preparation method of oil-based polyurethane slow-release nitrogen fertilizers. Background technique

[0002] my country is a large agricultural country, and chemical fertilizers play an important role in agricultural production. However, the effective nutrient utilization rate of chemical fertilizers in my country is not high, the waste of chemical fertilizers is large, and the actual absorption of crops is very small, which not only causes serious pollution of soil and water bodies, but also leads to a huge waste of energy and financial resources.

[0003] The emergence of coated fertilizers has effectively alleviated this problem. Coated fertilizer is a kind of slow / controlled release fertilizer that has developed rapidly in recent years. It uses water-soluble fertilizer particles as the core, and low water-soluble or...

Examples

Embodiment 1

[0036] Weigh 25 parts of large particle urea, 1.5 parts of ZnO (urea precipitation method) catalyst and 25 parts of castor oil in a flask, heat it to a reaction temperature of 70 °C, and feed inert gas N 2 , the flow rate was controlled at 100mL / min, and the reaction was carried out for 5h without stirring. Subsequently, the grafted urea was collected, placed in a beaker, 12.5 parts of ethylenediamine was added, and the polymerization reaction was carried out at room temperature (25°C). The reaction time was 2h. The coated urea was taken out and dried naturally overnight, and finally dried at 40°C for 24h. , to obtain polyurethane-coated urea slow-release fertilizer.

[0037] Slow-release performance test: use p-dimethylaminobenzaldehyde color spectrophotometry to detect the content of urea in the aqueous solution of polyurethane slow-release nitrogen fertilizer, and then know the slow-release performance of the fertilizer. The method is as follows: Take 5.00g of polyurethane...

Embodiment 2

[0039] Weigh 25 parts of large particle urea, 1.5 parts of ZnO (roasted zinc nitrate) catalyst and 25 parts of castor oil in a flask, heat it to a reaction temperature of 70 ° C, and feed inert gas N 2 , the flow rate was controlled at 100mL / min, and the reaction was carried out for 5h without stirring. Subsequently, the grafted urea was collected, placed in a beaker, 12.5 parts of ethylenediamine was added, and the polymerization reaction was carried out at room temperature. The reaction time was 2 hours. The coated urea was taken out and dried naturally overnight, and finally dried at 40°C for 24 hours to obtain polyurethane coated Cover with urea slow-release fertilizer.

[0040] Performance testing method is as embodiment 1

Embodiment 3

[0042]Weigh 25 parts of large particle urea, 1.5 parts of ZnO (roasted zinc oxalate) catalyst and 25 parts of castor oil in a flask, heat to the reaction temperature of 70 ° C, and pass inert gas N 2 , the flow rate was controlled at 100mL / min, and the reaction was carried out for 5h without stirring. Subsequently, the grafted urea was collected, placed in a beaker, 12.5 parts of ethylenediamine was added, and the polymerization reaction was carried out at room temperature. The reaction time was 2 hours. The coated urea was taken out and dried naturally overnight, and finally dried at 40°C for 24 hours to obtain polyurethane coated Cover with urea slow-release fertilizer.

[0043] Performance testing method is as embodiment 1

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