Organic liquid fertilizer existing in form of coated particles and preparation method of organic liquid fertilizer

Abstract

The invention relates to the field of preparation of organic liquid fertilizers, and particularly discloses an organic liquid fertilizer existing in the form of coated particles and a preparation method thereof.The organic liquid fertilizer is prepared from, by weight, 15-28 parts of modified polyurethane prepolymerization liquid, 30-45 parts of nutrient fertilizer, 8-15 parts of organic matter, 1-3 parts of stabilizer, 0.1-1 part of emulsifier, 40-65 parts of organic solvent and 35-50 parts of water. The organic liquid fertilizer disclosed by the invention can be used for increasing the fertility and the yield of medium-and-long-term crops, the utilization rate of the organic liquid fertilizer existing in a coated particle form is greatly improved, the waste of nutritional ingredients is reduced, the storage performance is stable, the fertilizer efficiency retention rate is high, the fertilizer application amount is reduced, and the fertilizer application cost is saved.

Description

Technical Field

[0001] The invention relates to the field of organic liquid fertilizer preparation, and specifically discloses an organic liquid fertilizer in the form of coated particles and a preparation method thereof. Background Art

[0002] The fertilizers used in my country's agricultural production are mainly traditional fertilizers, which have the limitation of fast nutrient release rate and easy loss due to volatilization, leaching and surface runoff. Therefore, controlling the level of fertilizer loss, retaining soil nutrients to the maximum extent, improving fertilizer utilization efficiency and reducing environmental pollution have always been the core issues of fertilizer improvement. Organic liquid fertilizer is a new type of fertilizer with high concentration, high fertilizer efficiency, multi-function and full nutrient efficiency. Compared with traditional chemical fertilizers, it can be absorbed by plants in a very short time to avoid loss, and it is simple and convenient to apply and easy to transport and store. However, the stability of liquid fertilizer is also a major disadvantage. Because its composition is easy to change and deteriorate, the effect of use is reduced, which has a certain impact on the growth of plants. Similarly, because liquid fertilizer is more likely to volatilize and lose, the utilization rate of fertilizer is greatly reduced, and at the same time, nutrients are wasted. If liquid organic fertilizer is applied at an improper concentration, fertilizer damage is prone to occur. The nutrients contained in liquid fertilizer are easy to combine and precipitate or antagonism between elements occurs, which will affect the effect of crop nutrient absorption.

[0003] The invention patent with application number 201610000009.1 discloses a microcapsule-encapsulated amino acid liquid mineral fertilizer and a preparation method thereof. The invention uses 60-75% of a composite amino acid liquid with a content of 10-25%, 1-5% of trace elements, 1-5% of potassium humate, 17-32% of mineral fertilizer, 1% of a stabilizer, 1% of a controlled release agent, and an appropriate amount of sodium hydroxide aqueous solution as raw materials, and produces liquid fertilizers and solid fertilizers and microencapsulates them to obtain the finished product. However, the liquid mineral fertilizer may have problems such as uneven concentration during fertilization and unstable absorption and application effects.

[0004] In view of this, it is particularly important that the present application discloses an organic liquid fertilizer in the form of coated particles. Summary of the invention

[0005] In view of the defects of the prior art, the present invention discloses an organic liquid fertilizer in the form of coated particles and a preparation method thereof. The organic liquid fertilizer disclosed by the present invention can be used for medium- and long-term crop fertilization and yield increase. The utilization rate of the organic liquid fertilizer in the form of coated particles is greatly improved, the waste of nutrients is reduced, and the storage performance is stable and the fertilizer efficiency retention rate is high, which is conducive to reducing the amount of fertilizer and saving the cost of fertilizer.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] On one hand, the present invention provides an organic liquid fertilizer in the form of coated particles, which comprises the following raw materials in parts by weight: 15 to 28 parts of modified polyurethane prepolymer liquid, 30 to 45 parts of nutrient fertilizer, 8 to 15 parts of organic matter, 1 to 3 parts of stabilizer, 0.1 to 1 part of emulsifier, 40 to 65 parts of organic solvent and 35 to 50 parts of water.

[0008] In some embodiments of the present invention, the preparation steps of the modified polyurethane prepolymer are as follows:

[0009] Add modified castor oil and diisocyanate into the reactor, introduce an inert atmosphere, heat up to 60-75°C, add the first catalyst, react for 2-4 hours under stirring, cool to 50-60°C, add the chain extender, react for 4-8 hours, and obtain the modified polyurethane prepolymer after drying.

[0010] In some embodiments of the present invention, the preparation steps of the modified castor oil are as follows:

[0011] Castor oil, 4-toluenesulfonyl isocyanate and a second catalyst are added into a reactor, an inert atmosphere is introduced, the temperature is raised to 60-75° C., and the reaction is stirred for 1-4 hours to obtain the modified castor oil.

[0012] In some embodiments of the present invention, the molar ratio of castor oil to 4-toluenesulfonyl isocyanate is 1:(0.1-0.3).

[0013] Preferably, the molar ratio of castor oil to 4-toluenesulfonyl isocyanate is 1:0.2.

[0014] In some embodiments of the present invention, the diisocyanate is dicyclohexylmethane diisocyanate.

[0015] In some embodiments of the present invention, the molar ratio of the modified castor oil to diisocyanate is 1:(3-4).

[0016] Preferably, the molar ratio of the modified castor oil to diisocyanate is 1:3.5.

[0017] The invention obtains organic liquid fertilizer in the form of coated particles by coating liquid fertilizer after modified polyurethane, thereby solving the problem of low utilization rate caused by the easy reaction of existing organic liquid fertilizer with water in soil. By changing the fertilizer structure, the utilization rate of nutrients is further improved, the amount of fertilizer applied can be reduced, and the cost of fertilizer application can be saved.

[0018] The applicant first modified castor oil by introducing 4-toluenesulfonyl isocyanate, and then reacted with diisocyanate and chain extender to synthesize modified polyurethane prepolymer as coating material to coat other components, so that the mechanical properties of the finished product, especially the negative pressure resistance and toughness, are further improved, and the pressure and abrasion resistance between particles during storage is improved. The possible reason is that the introduction of elemental sulfur and chain segments in the modified castor oil and the uniformly distributed cross-linking points inside the modified polyurethane prepolymer improve the orientation of the soft segment when the modified polyurethane prepolymer is subjected to force, and the oxidative polymerization reaction of the double bonds and active methylene in the castor oil during the film formation process makes the cross-linking density in a more suitable range, which together improves the pressure and abrasion resistance of the modified polyurethane prepolymer. When the organic liquid fertilizer is applied, the coating dissolves in water, effectively improving the utilization rate of the organic liquid fertilizer.

[0019] In some embodiments of the present invention, the nutrient fertilizer comprises, by weight, 5 to 10 parts of humic acid, 15 to 30 parts of urea, 6 to 10 parts of phosphate fertilizer, 20 to 25 parts of potash fertilizer and 3 to 6 parts of trace elements.

[0020] Preferably, the trace elements are Mo, Zn, Cu, B, Mn, Fe and Cl mixed in a mass ratio of 1: (8-10): (20-30): (0.5-1.0): (20-30): (8-9): (160-180).

[0021] In some embodiments of the present invention, the organic matter is water-soluble fermented organic matter.

[0022] In some embodiments of the present invention, the stabilizer is polyvinyl pyrrolidone.

[0023] In some embodiments of the present invention, the mass ratio of the organic matter to the stabilizer is 10:(1.3-2).

[0024] Preferably, the mass ratio of the organic matter to the stabilizer is 10:1.7.

[0025] The present invention significantly increases the stability of the liquid component when the specific stabilizer is added and the mass ratio of the specific stabilizer to the organic matter is controlled, thereby solving the problem of the influence of the fertilizer absorption efficiency of crops during application due to the easy combination and precipitation of the components and retaining the use effect.

[0026] In some embodiments of the present invention, the emulsifier is at least one of AEO-3, AEO-7 and AEO-9.

[0027] In some embodiments of the present invention, the organic solvent is a mixture of ethyl acetate and trimethylbenzene.

[0028] Another aspect of the present invention further provides a method for preparing an organic liquid fertilizer in the form of coated particles, comprising the following steps:

[0029] S1: adding nutrient fertilizer, organic matter and stabilizer to the first weight portion of organic solvent, heating until dissolved, cooling to room temperature, and adding emulsifier to obtain oil phase;

[0030] S2: dissolving the emulsifier in water to obtain an aqueous phase, and then transferring the aqueous phase to the oil phase of step S1, stirring and emulsifying for 1 to 2 hours to obtain an emulsion;

[0031] S3: Mix the modified polyurethane prepolymer liquid, the emulsion of step S2 and the second weight part of organic solvent, adjust the pH to 3-5, raise the temperature to 60-70° C. and react for 1-2 hours. After the reaction is completed, filter, wash and dry to obtain the organic liquid fertilizer in the form of coated particles.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The organic liquid fertilizer disclosed in the present invention can be used for medium- and long-term crop fertilization and yield increase. The utilization rate of the organic liquid fertilizer in the form of coated particles is greatly improved, which reduces the waste of nutrients. In addition, the storage performance is stable and the fertilizer efficiency retention rate is high, which is conducive to reducing the amount of fertilizer applied and saving fertilizer costs.

[0034] (2) The present invention obtains an organic liquid fertilizer in the form of coated particles by coating liquid fertilizer with modified polyurethane, thereby solving the problem of low utilization rate caused by the easy reaction of existing organic liquid fertilizer with water in the soil. By changing the fertilizer structure, the utilization rate of nutrients is further improved, the amount of fertilizer applied can be reduced, and the cost of fertilizer application can be saved.

[0035] (3) The present invention significantly increases the stability of the liquid component when the specific stabilizer is added and the mass ratio of the specific stabilizer to the organic matter is controlled. This solves the problem that the components are easily combined and precipitated, which affects the fertilizer absorption efficiency of crops during application, and retains the use effect. DETAILED DESCRIPTION

[0036] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0037] Unless otherwise specified, the reagents used below can be easily obtained from commercial companies, wherein the commercially available polyurethane prepolymer was purchased from Hubei Yamade Biopharmaceutical Co., Ltd., and polyvinyl pyrrolidone was purchased from Shandong Qiyun Chemical Technology Co., Ltd.

[0038] Preparation Example 1

[0039] The preparation steps of modified castor oil are as follows:

[0040] 9.33 g of castor oil, 6.90 g of 4-toluenesulfonyl isocyanate and 0.008 g of stannous octoate were added into the reactor, nitrogen atmosphere was introduced, the temperature was raised to 70° C., and the reaction was stirred for 3 h to obtain modified castor oil.

[0041] Preparation Example 2

[0042] The preparation steps of modified castor oil are the same as those of Preparation Example 1, except that the added amount of 4-toluenesulfonyl isocyanate is 8.28 g.

[0043] Preparation Example 3

[0044] The preparation steps of modified polyurethane prepolymer are as follows:

[0045] Add 11.3 g of modified castor oil and 0.40 g of dicyclohexylmethane diisocyanate into the reactor, introduce nitrogen atmosphere, raise the temperature to 70°C, add 0.0059 g of dibutyltin dilaurate, react for 3 hours under stirring, cool to 55°C, add 0.35 g of ethylene glycol, react for 6 hours, and obtain the modified polyurethane prepolymer after drying.

[0046] The modified castor oil used was obtained from Preparation Example 1.

[0047] Preparation Example 4

[0048] The preparation steps of the modified polyurethane prepolymer are the same as those in Preparation Example 3, except that the amount of dicyclohexylmethane diisocyanate added is 0.51 g.

[0049] Preparation Example 5

[0050] The preparation steps of the modified polyurethane prepolymer are the same as those of Preparation Example 3, except that the modified castor oil used is obtained from Preparation Example 2.

[0051] Preparation Example 6

[0052] The preparation steps of the modified polyurethane prepolymer are the same as those of Preparation Example 3, except that castor oil is used in an equal amount to replace the modified castor oil.

[0053] Unless otherwise specified, the organic matter used below are all water-soluble fermented organic matter purchased from Jiangsu Dirun Organic Fertilizer Technology Co., Ltd., the stabilizers used are all polyvinyl pyrrolidone, the emulsifiers used are all AEO-7, the organic solvents used are all obtained by mixing ethyl acetate and trimethylbenzene in a volume ratio of 1:1, and the trace elements used are all obtained by mixing Mo, Zn, Cu, B, Mn, Fe and Cl in a mass ratio of 1:9:25:0.7:25:8.5:170.

[0054] Example 1

[0055] An organic liquid fertilizer in the form of coated particles, comprising the following raw materials in parts by weight: 21.5 parts of modified polyurethane prepolymer liquid, 37.5 parts of nutrient fertilizer, 11.5 parts of organic matter, 2 parts of stabilizer, 0.5 parts of emulsifier, 52.5 parts of organic solvent and 42.5 parts of water;

[0056] The modified polyurethane prepolymer used was prepared in Preparation Example 3;

[0057] Each portion of nutrient fertilizer used contains 7.5 parts of humic acid, 22.5 parts of urea, 8 parts of phosphate fertilizer, 22.5 parts of potassium fertilizer and 4.5 parts of trace elements.

[0058] The method for preparing the organic liquid fertilizer in the form of coated particles in this embodiment comprises the following steps:

[0059] S1: adding nutrient fertilizer, organic matter and stabilizer to 3 / 4 weight parts of organic solvent, heating until dissolved, cooling to room temperature, and adding emulsifier to obtain oil phase;

[0060] S2: dissolving the emulsifier in water to obtain an aqueous phase, and then transferring the aqueous phase to the oil phase of step S1, stirring and emulsifying for 1.5 hours to obtain an emulsion;

[0061] S3: Mix the modified polyurethane prepolymer liquid, the emulsion of step S2 and 1 / 4 weight part of organic solvent, adjust the pH to 4, heat to 65° C. and react for 1.5 hours. After the reaction is completed, filter, wash and dry to obtain an organic liquid fertilizer in the form of coated particles.

[0062] Example 2

[0063] An organic liquid fertilizer in the form of coated particles, comprising the following raw materials in parts by weight: 15 parts of modified polyurethane prepolymer liquid, 30 parts of nutrient fertilizer, 8 parts of organic matter, 1 part of stabilizer, 0.1 part of emulsifier, 40 parts of organic solvent and 35 parts of water;

[0064] The modified polyurethane prepolymer used was prepared in Preparation Example 3;

[0065] Each portion of nutrient fertilizer used contains 5 parts of humic acid, 15 parts of urea, 6 parts of phosphate fertilizer, 20 parts of potassium fertilizer and 3 parts of trace elements.

[0066] The method for preparing the organic liquid fertilizer in the form of coated particles in this embodiment comprises the following steps:

[0067] S1: adding nutrient fertilizer, organic matter and stabilizer to 3 / 4 weight parts of organic solvent, heating until dissolved, cooling to room temperature, and adding emulsifier to obtain oil phase;

[0068] S2: dissolving the emulsifier in water to obtain an aqueous phase, and then transferring the aqueous phase to the oil phase of step S1, stirring and emulsifying for 1 hour to obtain an emulsion;

[0069] S3: Mix the modified polyurethane prepolymer liquid, the emulsion of step S2 and 1 / 4 weight part of organic solvent, adjust the pH to 5, heat to 60° C. and react for 1 hour. After the reaction is completed, filter, wash and dry to obtain an organic liquid fertilizer in the form of coated particles.

[0070] Example 3

[0071] An organic liquid fertilizer in the form of coated particles, comprising the following raw materials in parts by weight: 28 parts of modified polyurethane prepolymer liquid, 45 parts of nutrient fertilizer, 15 parts of organic matter, 3 parts of stabilizer, 1 part of emulsifier, 65 parts of organic solvent and 50 parts of water;

[0072] The modified polyurethane prepolymer used was prepared in Preparation Example 3;

[0073] Each portion of nutrient fertilizer used contains 10 parts of humic acid, 30 parts of urea, 10 parts of phosphate fertilizer, 25 parts of potash fertilizer and 6 parts of trace elements;

[0074] The method for preparing the organic liquid fertilizer in the form of coated particles in this embodiment comprises the following steps:

[0075] S1: adding nutrient fertilizer, organic matter and stabilizer to 3 / 4 weight parts of organic solvent, heating until dissolved, cooling to room temperature, and adding emulsifier to obtain oil phase;

[0076] S2: dissolving the emulsifier in water to obtain an aqueous phase, and then transferring the aqueous phase to the oil phase of step S1, stirring and emulsifying for 2 hours to obtain an emulsion;

[0077] S3: Mix the modified polyurethane prepolymer liquid, the emulsion of step S2 and 1 / 4 weight part of organic solvent, adjust the pH to 3, heat to 70° C. and react for 1 hour. After the reaction is completed, filter, wash and dry to obtain an organic liquid fertilizer in the form of coated particles.

[0078] Example 4

[0079] An organic liquid fertilizer in the form of coated particles and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the modified polyurethane prepolymer liquid used is obtained from Preparation Example 4.

[0080] Example 5

[0081] An organic liquid fertilizer in the form of coated particles and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the modified polyurethane prepolymer liquid used is obtained from Preparation Example 5.

[0082] Example 6

[0083] An organic liquid fertilizer in the form of coated particles and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the modified polyurethane prepolymer liquid used is obtained from Preparation Example 6.

[0084] Example 7

[0085] An organic liquid fertilizer in the form of coated particles and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the amount of stabilizer added is 1.2 parts by weight.

[0086] Comparative Example 1

[0087] An organic liquid fertilizer in the form of coated particles and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that an equal amount of commercially available polyurethane prepolymer liquid is used to replace the modified polyurethane prepolymer liquid.

[0088] Performance Test:

[0089] The organic liquid fertilizer in the form of coated particles prepared in the above Examples 1-7 and Comparative Example 1 was subjected to the following performance tests. The specific test results are shown in Table 1:

[0090] (1) Compression performance test: The compressive strength of each organic liquid fertilizer was tested using BST-03 particle compression test equipment;

[0091] (2) Yield-increasing effect test: Wheat was used as the test crop, and field fertilization of equal areas was compared under normal temperature conditions. The test adopted a randomized block design. 24 mu of wheat was planted in the test field and randomly divided into 8 groups, each with 3 mu. The organic liquid fertilizers prepared in Examples 1-7 and Comparative Example 1 were used accordingly. After being diluted with water at a mass ratio of 1:200, the wheat roots were irrigated. The amount used per mu was 50 jin. The average per mu yield of wheat at harvest was calculated to characterize the yield-increasing effect.

[0092] Table 1

[0093]

[0094]

[0095] It can be seen from Table 1 that the organic liquid fertilizer in the form of coated particles disclosed in Examples 1-3 of the present invention has good compression resistance and good fertilizer efficiency and yield-increasing effect.

[0096] By comparing Example 4 with Example 1, it can be seen that when the amount of dicyclohexylmethane diisocyanate added in the preparation of the modified polyurethane prepolymer solution is changed, the compressive resistance of the coated particles will decrease;

[0097] By comparing Example 5 with Example 1, it can be seen that when preparing the modified polyurethane prepolymer, when the amount of 4-toluenesulfonyl isocyanate added during the modification of the modified castor oil is changed, the compression resistance of the coated particles will decrease, and at the same time, the fertilizer efficiency will be adversely affected to a certain extent;

[0098] By comparing Example 6 with Example 1, it can be seen that when preparing the modified polyurethane prepolymer liquid, directly using unmodified castor oil to react with dicyclohexylmethane diisocyanate will affect the coating rate and water absorption rate of the coated particles, affect the water-soluble effect of the coating, affect the fertilizer effect, and the compression resistance of the coated particles will also decrease;

[0099] By comparing Example 7 with Example 1, it can be seen that when the mass ratio of organic matter to stabilizer changes, the fertilizer efficiency will decrease. This may be due to the nutrient binding and precipitation of organic matter, which affects the absorption effect of nutrients by the fertilized crops.

[0100] From the comparison between Comparative Example 1 and Example 1, it can be seen that when the modified polyurethane prepolymer liquid is replaced by an equal amount of commercially available polyurethane prepolymer liquid, the compressive strength and fertilizer efficiency of the coated particles are decreased to varying degrees.

[0101] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An organic liquid fertilizer in the form of coated particles, characterized in that: The organic liquid fertilizer comprises the following raw materials in parts by weight: 15 to 28 parts of modified polyurethane prepolymer liquid, 30 to 45 parts of nutrient fertilizer, 8 to 15 parts of organic matter, 1 to 3 parts of stabilizer, 0.1 to 1 part of emulsifier, 40 to 65 parts of organic solvent and 35 to 50 parts of water.

2. The organic liquid fertilizer in the form of coated particles according to claim 1, characterized in that: The preparation steps of the modified polyurethane prepolymer solution are as follows: Add modified castor oil and diisocyanate into the reactor, introduce an inert atmosphere, heat up to 60-75°C, add the first catalyst, react for 2-4 hours under stirring, cool to 50-60°C, add the chain extender, react for 4-8 hours, and obtain the modified polyurethane prepolymer after drying.

3. The organic liquid fertilizer according to claim 2, wherein: The preparation steps of the modified castor oil are as follows: Castor oil, 4-toluenesulfonyl isocyanate and a second catalyst are added into a reactor, an inert atmosphere is introduced, the temperature is raised to 60-75° C., and the reaction is stirred for 1-4 hours to obtain the modified castor oil.

4. The organic liquid fertilizer in the form of coated particles according to claim 3, characterized in that: The molar ratio of the castor oil to 4-toluenesulfonyl isocyanate is 1:(0.1-0.3).

5. The organic liquid fertilizer in the form of coated particles according to claim 2, characterized in that: The diisocyanate is dicyclohexylmethane diisocyanate.

6. The organic liquid fertilizer in the form of coated particles according to claim 2, characterized in that: The molar ratio of the modified castor oil to diisocyanate is 1:(3-4).

7. The organic liquid fertilizer in the form of coated particles according to claim 1, characterized in that: In parts by weight, the nutrient fertilizer comprises 5 to 10 parts of humic acid, 15 to 30 parts of urea, 6 to 10 parts of phosphate fertilizer, 20 to 25 parts of potash fertilizer and 3 to 6 parts of trace elements.

8. The organic liquid fertilizer in the form of coated particles according to claim 1, characterized in that: The organic matter is water-soluble fermented organic matter.

9. The organic liquid fertilizer in the form of coated particles according to claim 1, characterized in that: The mass ratio of the organic matter to the stabilizer is 10:(1.3-2).

10. A method for preparing an organic liquid fertilizer in the form of coated particles according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: adding nutrient fertilizer, organic matter and stabilizer into an organic solvent, heating until dissolved, cooling to room temperature, and then adding emulsifier to obtain an oil phase; S2: dissolving the emulsifier in water to obtain an aqueous phase, and then transferring the aqueous phase to the oil phase of step S1, stirring and emulsifying for 1 to 2 hours to obtain an emulsion; S3: Mixing the modified polyurethane prepolymer, the emulsion of step S2 and the organic solvent, adjusting the pH to 3-5, heating to 60-70° C. for reaction for 1-2 hours, filtering, washing and drying after the reaction to obtain the organic liquid fertilizer in the form of coated particles.

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