Anti-seepage long-acting functional fertilizer and preparation method thereof

Abstract

The invention provides an anti-seepage long-acting functional fertilizer and a preparation method thereof. The anti-seepage long-acting functional fertilizer comprises fertilizer main body particles, a hydrophilic protection film layer and a hydrophobic isolation water layer, wherein the hydrophilic protection film layer is a polyvinyl alcohol film layer, and the hydrophobic isolation water layer is polycaprolactone of biodegradable molecules. The preparation method has the beneficial effects that the existing common fertilizer main body particles are firstly coated with the hydrophilic protective film layer so as to play a role in isolation and protection; therefore, the purpose of preventing leakage is achieved, and the functional organic fertilizer can slowly release effective components for a long time. Furthermore, polycaprolactone of a hydrophobic material is introduced to the outer surface of the hydrophilic protective film layer through a polymerization reaction, and the polycaprolactone is insoluble in water, so that the fertilizer particles cannot be directly dissolved and consumed after being soaked in rainy seasons, and the service cycle length of the fertilizer particles is prolonged; and through slow degradability of polycaprolactone, an internal hydrophilic film layer and fertilizer particles are exposed, so that the purpose of application is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of biological organic fertilizers, and particularly relates to a technology for avoiding rapid water-soluble loss of fertilizer particles through hydrophobicity. Background Art

[0002] Fertilizers play a crucial role in agricultural production. Their main functions include providing nutrients for plants, increasing soil fertility, improving crop yields, and enhancing crop quality.

[0003] Among traditional fertilizers, water-soluble fertilizers are commonly used. Such fertilizers can more easily release nutrients and promote plant growth. However, water-soluble fertilizers also have a prominent problem. That is, during the rainy season, a large amount of rainwater will quickly dissolve and absorb the fertilizer, causing the fertilizer to be utilized too quickly, unable to be used effectively for a long time, and also resulting in uneven distribution due to water flow and other reasons; or the fertilizer is washed to other places.

[0004] Therefore, for existing fertilizer particles, if a hydrophobic material can be added to the surface, it can avoid the problems of being quickly soaked, dissolved, and washed away by rainwater, so as to achieve anti-leakage and improve the long-term use of fertilizers. In the prior art, some technologies for improving fertilizer particles by adding hydrophobic materials to the surface have emerged. However, their adhesion is poor. This is because the fertilizer particles themselves are hydrophilic. Therefore, directly attaching hydrophobic materials will cause difficulties in attachment or loose attachment, resulting in problems such as peeling and instability. On the other hand, the surface materials used are not biocompatible materials, which is not conducive to plant growth and is likely to damage plants or the soil. Therefore, the anti-leakage effect of functional fertilizers in the prior art needs to be improved. Summary of the Invention

[0005] To solve the problems existing in the above technologies, the present invention provides a functional fertilizer technology with a hydrophobic surface, good affinity between the film layer and the surface of the fertilizer particles, not prone to peeling and peeling, thereby achieving anti-leakage and long-term use.

[0006] The present invention provides a long-lasting anti-leakage functional fertilizer, which includes a fertilizer main body particle, a hydrophilic protective film layer, and a hydrophobic isolation water layer. Among them, the hydrophilic protective film layer is a polyvinyl alcohol film layer, and the hydrophobic isolation water layer is polycaprolactone of biodegradable molecules.

[0007] Preferably, the type of the fertilizer main body particle is organic fertilizer, nitrogen fertilizer, phosphate fertilizer, or potassium fertilizer.

[0008] Preferably, the size of the fertilizer main body particle is 2 - 4 mm, and the thickness of the polyvinyl alcohol film layer is 0.05 mm to 0.2 mm.

[0009] The preparation method of the anti-leakage long-acting functional fertilizer provided by the present invention includes the following steps:

[0010] Step 1: Dilute the polyvinyl alcohol raw material with water to prepare a solution, immerse the main fertilizer particles into the solution, and then take them out.

[0011] Step 2: Dry to form a hydrophilic protective film layer on the surface of the main fertilizer particles. The hydrophilic protective film layer is a film structure formed by polyvinyl alcohol.

[0012] Step 3: Initiate the ring-opening polymerization reaction of caprolactone through the hydroxyl group OH on the film structure to obtain a hydrophobic layer structure covered with polycaprolactone on the outer surface.

[0013] Preferably, in Step 1, the ratio of polyvinyl alcohol to water is 1:1 to 1:5, and the immersion time is 5 seconds to 30 seconds.

[0014] In Step 2, the drying temperature is 50°C to 70°C; the thickness of the hydrophilic protective film layer is 0.05 mm to 0.2 mm.

[0015] In Step 3, put the fertilizer particles loaded with the hydrophilic protective film layer into DMF, and perform pre-reaction activation under the condition of 60°C to 80°C; add caprolactone and the catalyst Sn(Oct) 2 , react at 110°C to 120°C for 5 minutes to 20 minutes. After the reaction, separate to obtain a solid, rinse it clean and dry to obtain the final product. At room temperature, the solubility of polyvinyl alcohol in DMF is poor, but under heating conditions, such as heating to 100°C or even higher temperature, its solubility will increase. Therefore, the temperature is controlled at 60°C to 80°C to avoid the direct dissolution of the particles.

[0016] Preferably, the mass dosage of caprolactone is 0.5 times to 2 times the weight of the hydrophilic protective film layer.

[0017] The dosage of the catalyst Sn(Oct)2 is 0.1% to 1% of the mass of caprolactone.

[0018] The beneficial effects of the present invention are as follows: First, wrap the existing ordinary main fertilizer particles with a hydrophilic protective film layer to play an isolation and protection role, and the hydrophilic film layer has good adhesion to the fertilizer particles and is not easy to have problems such as peeling and delamination. Thus, the purpose of anti-leakage is achieved, and the functional organic fertilizer can slowly and long-term release the active ingredients.

[0019] Furthermore, polycaprolactone, a hydrophobic material, is introduced on the outer surface of the hydrophilic protective film layer through a polymerization reaction. Polycaprolactone is insoluble in water, so it will not directly dissolve and consume the fertilizer particles after soaking in the rainy season, extending the service life of the fertilizer particles; and through the slow degradation of polycaprolactone, the internal hydrophilic film layer and fertilizer particles are exposed to achieve the purpose of application.

[0020] Polycaprolactone is a biomaterial. Substances such as carbon dioxide released after its degradation are beneficial to plant growth, can promote plant growth, and will not cause adverse effects on plant growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a reaction schematic diagram of the improved film-coated structure formed from the ordinary fertilizer granules of the present invention.

[0022] Figure 2 It is a physical diagram of the ordinary fertilizer granules of the present invention and a physical diagram after reacting to load a hydrophilic film layer and polycaprolactone.

[0023] Figure 3 It is a schematic cross-sectional structure diagram of the improved fertilizer granules obtained. DETAILED DESCRIPTION OF THE INVENTION

[0024] Example 1:

[0025] The preparation method of the anti-leakage long-acting functional fertilizer provided in this example includes the following steps:

[0026] Combined with Figure 1 the shown preparation reaction schematic diagram:

[0027] Step 1: Dilute 10 ml of polyvinyl alcohol (with a density of 1.080 g / cm 3 , provided by Shanghai Aladdin Reagent Co., Ltd., and scale up the experiment to obtain corresponding fertilizer granules; the weight is converted to 10.8 g) raw material with 20 ml of water to prepare a solution, immerse 10 g of the main fertilizer granules into the solution, and then take them out, and the immersion time is 5 seconds to 30 seconds;

[0028] Step 2: Dry in an oven to form a hydrophilic protective film layer on the surface of the main fertilizer granules. The hydrophilic protective film layer is a film structure formed by polyvinyl alcohol; in Step 2, the drying temperature is 50°C to 70°C; the thickness of the hydrophilic protective film layer is 0.05 mm to 0.2 mm.

[0029] Step 3: Initiate the ring-opening polymerization reaction of caprolactone through the hydroxyl OH on the membrane structure to obtain a hydrophobic layer structure with polycaprolactone covering the outer surface. In Step 3, put the fertilizer granules loaded with the hydrophilic protective film layer into DMF (N,N-dimethylformamide), and carry out pre-reaction activation under the condition of 60°C to 80°C; add caprolactone and catalyst Sn(Oct) 2, react at 110°C to 120°C for 8 minutes. After the reaction ends, separate the solid matter, rinse it clean and dry it to obtain the final product. The dosage of DMF is 3 to 10 times the volume of the materials in Step 2. Here, the dosage of DMF is 40 ml, that is, the materials are dispersed in the DMF solution and stirred. The dosage of caprolactone is the same as that of polyvinyl alcohol, which is 10.8 g; the dosage of Sn(Oct) 2 is about 0.2% of caprolactone, that is, 0.2 g.

[0030] At room temperature, the solubility of the fertilizer particles wrapped with polyvinyl alcohol in DMF is poor, but under heating conditions, such as heating to 100°C or even higher temperatures, its solubility will increase. Therefore, control the temperature at 60°C to 80°C to avoid the direct dissolution of the particles.

[0031] Experimental Example 1: As Figure 2 shown are the fertilizer particles in the prepared examples, which are somewhat different from the ordinary fertilizer particles before treatment. On the one hand, their color has become darker, mainly because the introduction of some intermediate substances such as catalysts during the reaction has changed the color of the film layer; another change is that the size of the particles has changed to a certain extent, and the average diameter of the particles has increased.

[0032] In the obtained fertilizer particles, the adhesion of the film layer is good, and no obvious problems such as peeling and delamination are found. The whole is round and has good wrapping properties.

[0033] In Figure 3 is a schematic diagram of such prepared fertilizer particles, which includes the main core structure fertilizer, and then is coated with a hydrophilic protective film layer PVA and an outer hydrophobic protective layer PCL.

[0034] Experimental Example 2: Use the fertilizer particles obtained in this Example 1 and the existing ordinary fertilizers for plant cultivation. Specifically, plant winter wheat and corn with the two fertilizers over a one-year period and conduct joint observations. The experiment was carried out in the central and southern regions of Hebei. The corn was sown in early June and harvested in mid-October; the wheat was planted in early November and harvested in June of the following year. Calculate the time from the planting of wheat in November of the first year to the harvest of corn in October of the second year to complete the whole process, and calculate the yield.

[0035] Example 1 is the fertilizer granule prepared by the method provided by the present invention, and is applied for planting according to the following component ratio, that is, the fertilizer granule prepared by the method provided by the present invention is mixed and compounded with ordinary fertilizer granules. Among them, the component of Example 1 is 70% by weight of the fertilizer granule prepared by the method provided by the present invention, and the remaining 30% is ordinary fertilizer granules. The ordinary fertilizer granules are used to quickly release the effective components of the fertilizer in the early stage, while the improved fertilizer granules of the present invention gradually release the internal fertilizer effective components, and the surface hydrophobic film alleviates the problem of rainwater soaking and loss.

[0036] The fertilizer of Example 1 was applied in November, and it was used only once, and the effective amount of the fertilizer used was 100 parts. Control group 1 is the existing ordinary fertilizer, which was applied in November and only applied once, and the effective amount of the fertilizer is 100 parts; the effective amount refers to the amount of the internal fertilizer granules after removing the surface attached film layer (the film introduced by the improvement of the present invention). Control group 2 is the existing ordinary fertilizer, and it is applied in two times, once in November and once in April of the following year, and the effective amount used each time is 50 parts. Control group 3 is the existing ordinary fertilizer. Control group 3 started from November of the first year, and 10 parts were applied every month until 100 parts of fertilizer were used up in August of the following year.

[0037] Table 1 summarizes the yield data obtained after applying fertilizer granules in the examples of the present invention and multiple control groups for wheat and corn planting. It can be seen from the following table data that in Example 1, degradable fertilizer granules were used, which were used in combination with ordinary fertilizers. In this way, during the growth process of plants, due to the protective film layer of the fertilizer granules, the effective substances will not be quickly released, and the nutrients therein can be slowly released for a long time, achieving the purpose of maintaining a relatively high harvest yield with one application. In Control group 1, the fertilizer was applied only once in November of the first year. The wheat yield was slightly lower than that of Example 1, but the corn yield decreased significantly. This is because the fertilizer was quickly released and applied, and it was difficult to be stored for a long time in a rainy environment and was prone to rapid failure. Therefore, the fertility effect decreased particularly significantly when planting corn in the second year.

[0038] In Control group 2, the wheat yield and the corn yield were both slightly lower than those of Example 1. The fertilizer was applied in two times, but due to the problem of still being impacted by rainwater and quickly released in the middle, the fertility of the fertilizer was affected.

[0039] In Control Group 3, the technique of applying fertilizers monthly was adopted. This method is the most effective in ensuring soil fertility. Although ordinary fertilizers were used, due to the regular and frequent application of nutrient fertilizers, it was able to ensure the nutrients required for plant growth to the greatest extent, and its yield was guaranteed, even higher than that of Example 1. However, since Control Group 3 needed to apply fertilizers monthly, it consumed more time, which is not applicable in actual agricultural production. The following units are all the yield per mu of land.

[0040] Example 1 Control Group 1 Control Group 2 Control Group 3 Wheat Yield 425KG 403KG 402KG 432KG Corn Yield 580KG 486KG 535KG 586KG Total Yield 1005KG 889KG 937KG 1018KG

Claims

1. A leakage-proof long-acting functional fertilizer, characterized in that: It includes fertilizer main body particles, a hydrophilic protective film layer and a hydrophobic isolation water layer; wherein the hydrophilic protective film layer is a polyvinyl alcohol film layer, and the hydrophobic isolation water layer is polycaprolactone of a biodegradable molecule.

2. The anti-leakage long-acting functional fertilizer according to claim 1, characterized in that: The types of fertilizer main body particles are organic fertilizer, nitrogen fertilizer, phosphorus fertilizer, potash fertilizer or compound fertilizer.

3. The anti-leakage long-acting functional fertilizer according to claim 1, characterized in that: The size of the fertilizer main particles is 2-4 mm, and the thickness of the polyvinyl alcohol film layer is 0.05 mm to 0.2 mm.

4. The method for preparing the anti-leakage long-acting functional fertilizer according to any one of claims 1 to 3, characterized in that: The following steps are included: Step 1: dilute the polyvinyl alcohol raw material with water to prepare a solution, immerse the fertilizer main particles in the solution, and then take them out; Step 2: drying to form a hydrophilic protective film layer on the surface of the fertilizer main particles, wherein the hydrophilic protective film layer is a film structure formed by polyvinyl alcohol; Step 3: The hydroxyl groups OH on the membrane structure are used to initiate the ring-opening polymerization of caprolactone, thereby obtaining a hydrophobic layer structure with the outer surface covered with polycaprolactone.

5. The method for preparing the anti-leakage long-acting functional fertilizer according to claim 4, characterized in that: In step 1, the ratio of polyvinyl alcohol to water is 1:1 to 1:5, and the immersion time is 5 seconds to 30 seconds; In step 2, the drying temperature is 50° C. to 70° C.; the thickness of the hydrophilic protective film layer is 0.05 mm to 0.2 mm. In step 3, the fertilizer particles loaded with a hydrophilic protective film layer are placed in DMF and activated before the reaction at 60°C to 80°C; caprolactone and catalyst Sn(Oct)2 are added, and the reaction is carried out at 110°C to 120°C for 5 minutes to 20 minutes. After the reaction is completed, the solid matter is separated, rinsed and dried to obtain the final product.

6. The method for preparing the anti-leakage long-acting functional fertilizer according to claim 5, characterized in that: The mass dosage of caprolactone is 0.5 to 2 times of the weight of the hydrophilic protective film layer; The amount of the catalyst Sn(Oct)2 used is 0.1% to 1% of the mass of caprolactone.

7. According to the use of the anti-seepage long-acting functional fertilizer as a fertilizer according to claims 1 to 3, the anti-seepage long-acting functional fertilizer is mixed with ordinary fertilizer particles as a fertilizer for composite use.

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