A medicine-fertilizer composite carrier with controlled-loss and slow-release function and preparation method thereof

Abstract

The present invention provides a medicine-fertilizer composite carrier with loss-control and sustained-release functions and a preparation method thereof. The medicine-fertilizer composite carrier comprises the following raw materials in parts by weight: 80-100 parts of amphiphilic block copolymers, 5-10 parts of natural minerals, 3-7 parts of power plant waste, and 5-15 parts of modified diatomaceous earth. The medicine-fertilizer composite carrier provided by the present invention has good loss-control and sustained-release functions, can be widely used in the field of sustained-release carrier materials, and has good commercial application value.

Description

Technical Field

[0001] The invention relates to the field of slow-release carrier materials, in particular to the field of slow-release carrier materials for medicine and fertilizer, and in particular to a medicine-fertilizer composite carrier with a controlled-release slow-release function and a preparation method thereof. Background Art

[0002] Pesticide fertilizer refers to a new type of ecological compound fertilizer formed by mixing pesticides and fertilizers in a certain ratio and stabilizing fertilizers and pesticides in a specific compound system through certain process technologies. For the sustainable development of contemporary agriculture, pesticide fertilizer can combine the two operation steps in the field into one, which not only saves labor but also reduces the consumption of time and energy, becoming a new development trend of modern agriculture.

[0003] Although medicated fertilizers have the above-mentioned advantages and excellent development potential in the field of modern pesticides, there are still some inevitable defects. For example, medicated fertilizers are easy to lose and lose during use, resulting in low utilization rates of fertilizers and pesticides; medicated fertilizers have relatively fixed nutrient ratios and relatively single products, which make them have high requirements for the environment and crop types, resulting in limited scope of use; and medicated fertilizers are easily affected by external factors such as moisture and temperature, resulting in unstable quality and reduced original effects of medicated fertilizers.

[0004] Patent CN 104291973B discloses a slow-release carrier and its application in the slow release of water or fertilizer required by potted crops. The slow-release carrier provided in the application is mainly synthesized from components such as starch and gelatinizer, and can be used as a carrier of water and fertilizer, and can achieve the effect of slow release of water and fertilizer, and the slow release has a long effective period, but it does not mention that it can be used as a carrier for slow release of medicine and fertilizer, and does not mention the hydrophilicity and hydrophobicity of the carrier, which has the problem of limited scope of use; Patent CN 109232077A discloses a multifunctional medicinal fertilizer and its preparation method. The slow-release coating layer in the application includes neutral bentonite, mesoporous molecular sieve and other components, which can achieve controllable release of pesticides and fertilizers, and has the advantages of rapid and stable fertilizer effect, but does not solve the problem that the medicine and fertilizer are easily affected by external factors, resulting in their low stability.

[0005] Therefore, there is an urgent need in the market for a composite carrier for fertilizers and drugs that can make the fertilizers and drugs work efficiently and has a controlled loss and slow release function. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention selects amphiphilic block copolymers and modified diatomaceous earth as the main components of the medicinal fertilizer composite carrier, and then adds natural minerals and power plant waste to prepare a medicinal fertilizer composite carrier with the function of controlled loss and slow release.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] On one hand, the present invention provides a medicine-fertilizer composite carrier with a controlled loss and sustained release function. The medicine-fertilizer composite carrier comprises the following raw materials in parts by weight: 80-100 parts of an amphiphilic block copolymer, 5-10 parts of natural minerals, 3-7 parts of power plant waste, and 5-15 parts of modified diatomaceous earth.

[0009] In some embodiments of the present invention, the method for preparing the amphiphilic block copolymer comprises the following steps:

[0010] (1) tert-butyl N-(2,3-dihydroxypropyl)carbamate, tetrahydrofuran and triethylamine are mixed and stirred, and methacryloyl chloride is added dropwise at -5-0°C, and the temperature is returned to room temperature, and stirred for 23-25 ​​hours, and then filtered, rotary evaporated, washed, and dried to obtain a reaction product 1 for later use;

[0011] (2) mixing the reaction product 1 of step (1), triethylamine and tetrahydrofuran, introducing an inert gas at -15 to -5°C, stirring, adding 2-chloro-2-oxo-1,3,2-dioxaphospholane and tetrahydrofuran, stirring, filtering, taking the filtrate, washing, and rotary evaporating to obtain a reaction product 2 for later use;

[0012] (3) Lactide, polyethylene glycol and stannous octoate are mixed, stirred, heated to 110-130° C. under an inert atmosphere for reaction for 1.5-2.5 h, chloroform and ether are added, filtered, the precipitate is collected, and dried to obtain polyethylene glycol-polylactic acid for later use;

[0013] (4) taking the polyethylene glycol-polylactic acid of step (3), adding the reaction product 2 of step (2), stannous octoate and tetrahydrofuran, passing an inert gas, reacting at 30-50° C. for 1-3 h, adding ether, filtering, and drying to obtain a reaction product 3 for later use;

[0014] (5) dissolving 2-mercaptothiophene and methyl 4'-pyridyl-4-benzoate in toluene, heating to reflux, rotary evaporation, adding sodium hydroxide solution, heating to reflux, cooling to room temperature, adding acetic acid solution dropwise until a white precipitate appears, filtering, washing, and drying to obtain reaction product 4 for later use;

[0015] (6) taking the reaction product 4 of step (5), adding triphenyl phosphate, ketoic acid, toluene and n-butanol, heating to reflux, filtering, washing and drying to obtain the reaction product 5 for use;

[0016] (7) Take the reaction product 3 of step (4), add the reaction product 5 of step (6), dichloromethane and trifluoroacetic acid, seal, stir for 8-10 hours, add petroleum ether, take the precipitate, and dry to obtain the amphiphilic block copolymer.

[0017] In some embodiments of the present invention, in step (3), the lactide is L-lactide; and the number average molecular weight of the polyethylene glycol is 4000-6000.

[0018] Preferably, the number average molecular weight of the polyethylene glycol is 4000.

[0019] In some embodiments of the present invention, in step (2), the mass ratio of the reaction product 1 and 2-chloro-2-oxo-1,3,2-dioxaphospholane is (1.6-2.6):1; in step (4), the mass ratio of polyethylene glycol-polylactic acid and the reaction product 2 of step (2) is 1:(0.2-0.3).

[0020] Preferably, in step (2), the mass ratio of reaction product 1 to 2-chloro-2-oxo-1,3,2-dioxaphospholane is 2.1:1; and in step (4), the mass ratio of polyethylene glycol-polylactic acid to reaction product 2 is 1:0.25.

[0021] In some embodiments of the present invention, in step (7), the mass ratio of reaction product 3 to reaction product 5 is 1:(0.03-0.07).

[0022] Preferably, in step (7), the mass ratio of reaction product 3 to reaction product 5 is 1:0.05.

[0023] Pesticides and fertilizers generally have the disadvantages of being easily lost and having poor stability, which leads to loss or deterioration of their effects. It is becoming increasingly important to prepare carriers that can control the loss of pesticides and fertilizers and have a sustained release effect. Chitosan substances with porous and core-shell structures are often used as carriers for pesticides and fertilizers, which can have a good sustained release effect. However, as a natural polymer, chitosan is easily affected by environmental factors such as temperature and humidity, resulting in poor stability. In addition, chitosan as a carrier mainly loads pesticides and fertilizers through physical effects such as hydrogen bonds and van der Waals forces between molecules, which are weaker than chemical bonding. As a result, the sustained release effect of pesticides and fertilizers of traditional chitosan carriers cannot be exerted in a long-term and stable manner. In addition, there are many types of pesticides and fertilizers, which are both hydrophilic and hydrophobic, and high requirements are also placed on the selectivity of carriers.

[0024] The applicant uses polyethylene glycol, which has good biocompatibility and is safe and non-toxic, as the hydrophilic block, and polylactic acid, which is environmentally friendly, non-toxic and degradable, as the hydrophobic block to synthesize polyethylene glycol-polylactic acid with dual hydrophilic and hydrophobic properties, and based on polyethylene glycol-polylactic acid, modifies it to synthesize an amphiphilic block copolymer, making it a drug and fertilizer carrier with good loss control and sustained release effects. On the one hand, the applicant used N-(2,3-dihydroxypropyl) tert-butyl carbamate to react with 2-chloro-2-oxo-1,3,2-dioxaphospholane, and reacted it with polyethylene glycol-polylactic acid to introduce polyphosphate groups. Polyphosphates have good biocompatibility, degradability and synthetic controllability, and are widely used in the field of carriers, laying the foundation for the successful and stable access of subsequent groups. In addition, the polyhydroxy structure in N-(2,3-dihydroxypropyl) tert-butyl carbamate provides reaction activity for the micelles formed by the amphiphilic block copolymer, so that the drug fertilizer can be efficiently loaded inside the amphiphilic block copolymer to achieve a sustained release effect. On the other hand, the applicant used 2-mercaptothiophene and 4'-pyridyl-4-benzoic acid methyl ester to react with triphenyl phosphate and keto acid to synthesize reaction product 4, and under the action of trifluoroacetic acid The protecting group is removed, and the reaction product 4 is grafted onto the polyphosphate end through an amide condensation reaction, wherein the pyridine group in 4'-pyridyl-4-benzoic acid methyl ester will stretch out in an aqueous solution due to electrostatic repulsion, and as the degree of stretching increases, the sustained-release effect of the fertilizer is also improved; the introduction of triphenyl phosphate causes the triphenylphosphine structure to be grafted into the amphiphilic block copolymer structure, thereby improving the antibacterial property, stability and lipophilicity of the carrier, which is beneficial to improving the sustained-release effect of the hydrophobic fertilizer, and an amide group is formed between triphenyl phosphate and the polyphosphate, so that the carrier has temperature responsiveness; the introduction of ketoic acid increases the temperature responsiveness and antioxidant properties of the carrier, and improves the stability of the carrier. Furthermore, a coordination bond is formed between the keto group and the pyridine group in ketoic acid, further improving the stability of the amphiphilic block copolymer and improving the fertilizer loss control and sustained-release effects of the carrier.

[0025] In some embodiments of the present invention, the natural mineral is attapulgite.

[0026] In some embodiments of the present invention, the power plant waste is fly ash.

[0027] In some embodiments of the present invention, the method for preparing the modified diatomaceous earth comprises the following steps:

[0028] 1) adding diatomaceous earth to deionized water, adding anionic surfactant, adjusting pH to 1-2, stirring, standing, filtering, washing, and drying to obtain product 1 for later use;

[0029] 2) mixing guanidine hydrochloride, sodium tripolyphosphate and deionized water, stirring, adding the product 1 of step 1), shaking, centrifuging, and drying to obtain product 2 for later use;

[0030] 3) Take the product 2 of step 2), add carvacrol, stir, filter under pressure, centrifuge, and dry to obtain modified diatomaceous earth.

[0031] Preferably, the anionic surfactant in step 1) is sodium dodecyl sulfate.

[0032] In some embodiments of the present invention, in step 2), the mass ratio of product 1 to guanidine hydrochloride is 1:(0.2-0.6).

[0033] Preferably, in step 2), the mass ratio of product 1 to guanidine hydrochloride is 1:0.4.

[0034] Natural diatomaceous earth is a non-toxic and harmless non-metallic mineral whose main chemical component is silicon dioxide. It has the characteristics of large pore size, large porosity, good adsorption, large surface area and stable chemical properties. It can be used as a good carrier for pesticides and fertilizers. However, diatomaceous earth has the disadvantages of being fragile and easy to breed bacteria.

[0035] On the one hand, the applicant introduced guanidine salt with high antibacterial properties to modify diatomite. Diatomite contains a large amount of silanol, which can dissociate into H + , making the surface of diatomaceous earth electronegative, while guanidine group is electrophilic and can be well combined with diatomaceous earth. Further, the applicant modifies the diatomaceous earth with anionic surfactant sodium dodecyl sulfate, thereby enhancing the electronegativity of the diatomaceous earth surface and making it more adsorbable to guanidine salt, thereby increasing the antibacterial and stability of the diatomaceous earth. On the other hand, the applicant pressurizes and filters the excess carvacrol and guanidine salt-modified diatomaceous earth to make the carvacrol with antioxidant and antibacterial effects fully enter the cavities of the diatomaceous earth and discharge the air of the diatomaceous earth at the same time, so that the modified diatomaceous earth has better antibacterial and antioxidant effects and a tighter structure, which solves the problem of diatomaceous earth being fragile and improves the stability of diatomaceous earth.

[0036] Furthermore, the phenolic group and the guanidine group in carvacrol will undergo a certain cross-linking effect, thereby promoting the improvement of the stability of the modified diatomaceous earth; further, there is a certain bonding effect between the guanidine group in the modified diatomaceous earth and the phosphate group in the amphiphilic block copolymer, and hydrogen bonds can be formed, which is beneficial to improving the stability of the composite carrier, thereby improving the controlled loss and sustained release effect of the composite carrier.

[0037] On the other hand, the present invention also provides a method for preparing the medicine-fertilizer composite carrier with controlled loss and slow release function described in the above technical solution, comprising the following steps:

[0038] The amphiphilic block copolymer, natural minerals, power plant waste and modified diatomaceous earth are placed in a reactor, stirred for 1-2 hours, and ground for 20-40 minutes to obtain a drug-fertilizer composite carrier with controlled loss and slow release function.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) The present invention selects amphiphilic block copolymers and modified diatomaceous earth as the main components of the medicinal fertilizer composite carrier, and then adds natural minerals and power plant waste to prepare a medicinal fertilizer composite carrier. Through the synergistic effect between the components, the medicinal fertilizer composite carrier has the function of controlled loss and sustained release.

[0041] (2) The present invention is based on amphiphilic polyethylene glycol-polylactic acid, and introduces polyphosphate and triphenylphosphine and keto acid structures to modify and synthesize an amphiphilic block copolymer, so that it has good amphiphilicity and also has good stability, antioxidant properties and temperature responsiveness, thereby improving the controlled loss and sustained release effect of the drug-fertilizer composite carrier.

[0042] (3) The present invention uses guanidine salt with high antibacterial properties to modify diatomaceous earth, and introduces excessive carvacrol to compound it, so that the stability and antibacterial properties of the diatomaceous earth are improved, thereby improving the controlled loss and slow release effect of the drug-fertilizer composite carrier.

[0043] (4) The drug-fertilizer composite carrier prepared by the present invention has good loss-control and sustained-release functions, can be widely used in the field of drug-fertilizer sustained-release carrier materials, and has good commercial application value. DETAILED DESCRIPTION

[0044] 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.

[0045] In the following examples, except for the amphiphilic block copolymer and modified diatomite, the other compound monomers and related reagents used can be purchased from the market, among which the number average molecular weight of polyethylene glycol is 4000, purchased from Hai'an Petrochemical Plant in Jiangsu Province; attapulgite was purchased from Shijiazhuang Zezhang Mining Co., Ltd.; fly ash was purchased from Shengtong Mineral Products Business Department of Lingshou County; diatomite was purchased from Yixing Junlian Diatomite Co., Ltd.

[0046] Preparation Example 1

[0047] The synthesis method of the amphiphilic block copolymer A comprises the following steps:

[0048] (1) 16 g of tert-butyl N-(2,3-dihydroxypropyl)carbamate, 60 ml of tetrahydrofuran and 25 ml of triethylamine were mixed and stirred for 15 min, 14 g of methacryloyl chloride was added dropwise at 0° C., the temperature was returned to room temperature, stirred for 24 h, filtered, rotary evaporated, washed with deionized water 3 times, and dried to obtain reaction product 1 for later use;

[0049] (2) 21 g of the reaction product 1 of step (1), 7 g of triethylamine and 50 ml of tetrahydrofuran were mixed, argon was introduced at -10°C, and the mixture was stirred for 15 min. 10 g of 2-chloro-2-oxo-1,3,2-dioxaphospholane and 20 ml of tetrahydrofuran were added, and the mixture was stirred for 8 h. The mixture was filtered, and the filtrate was washed with chloroform three times, and the reaction product 2 was obtained by rotary evaporation for later use.

[0050] (3) 50 g of L-lactide, 15 g of polyethylene glycol and 1.5 g of stannous octoate were mixed, stirred for 10 min, heated to 120° C. under a nitrogen atmosphere for reaction for 2 h, 40 ml of chloroform and 100 ml of ether were added, filtered, the precipitate was collected, and dried at 60° C. for 12 h to obtain polyethylene glycol-polylactic acid for use;

[0051] (4) Take 50 g of the polyethylene glycol-polylactic acid prepared in step (3), add 12.5 g of the reaction product 2 prepared in step (2), 2 g of stannous octoate and 50 ml of tetrahydrofuran, introduce argon, react at 40° C. for 2 h, add 100 ml of ether, filter, and dry at 40° C. for 12 h to obtain the reaction product 3 for later use;

[0052] (5) 10 g of 2-mercaptothiophene and 20 g of methyl 4'-pyridyl-4-benzoate were dissolved in 60 ml of toluene, heated under reflux at 80° C. for 4 h, and rotary evaporated. 30 ml of 30 wt % sodium hydroxide solution was added, and heated under reflux at 80° C. for 4 h. The mixture was cooled to room temperature, and 30 wt % acetic acid solution was added dropwise until a white precipitate appeared. The mixture was filtered, washed with deionized water for 3 times, and dried at 60° C. for 12 h to obtain reaction product 4 for later use.

[0053] (6) Take 10 g of the reaction product 4 of step (5), add 3.2 g of triphenyl phosphate, 2.8 g of keto acid, 40 ml of toluene and 10 ml of n-butanol, heat and reflux at 80° C. for 4 h, filter, wash with deionized water 3 times, and dry at 60° C. for 12 h to obtain the reaction product 5 for use;

[0054] (7) Take 40 g of the reaction product 3 of step (4), add 2 g of the reaction product 5 of step (6), 60 ml of dichloromethane and 10 ml of trifluoroacetic acid, seal, stir for 10 h, add 100 ml of petroleum ether, take the precipitate, and dry at 40° C. for 12 h to obtain the amphiphilic block copolymer A.

[0055] Preparation Example 2

[0056] The specific implementation manner of the amphiphilic block copolymer B is the same as that of the amphiphilic block copolymer A, except that the mass of the reaction product 1 in step (2) is replaced by 13 g.

[0057] Preparation Example 3

[0058] The specific implementation manner of the amphiphilic block copolymer C is the same as that of the amphiphilic block copolymer A, except that the mass of the reaction product 2 in step (4) is replaced with 7.5 g.

[0059] Preparation Example 4

[0060] The specific implementation manner of the amphiphilic block copolymer D is the same as that of the amphiphilic block copolymer A, except that the mass of the reaction product 5 in step (7) is replaced with 0.8 g.

[0061] Preparation Example 5

[0062] The specific implementation manner of the amphiphilic block copolymer E is the same as that of the amphiphilic block copolymer A, except that the mass of the reaction product 5 in step (7) is replaced by 4 g.

[0063] Preparation Example 6

[0064] The synthesis method of modified diatomite A comprises the following steps:

[0065] 1) Add 5 g of diatomaceous earth to 50 ml of deionized water, add 7.5 g of sodium dodecyl sulfate, add 36 wt % acetic acid solution dropwise to adjust the pH to 1.5, stir for 4 h, let stand for 2 h, filter, wash with deionized water 3 times, and dry at 60° C. for 12 h to obtain product 1 for later use;

[0066] 2) 2 g of guanidine hydrochloride, 0.4 g of sodium tripolyphosphate and 20 ml of deionized water were mixed, stirred for 4 h, 5 g of the product 1 of step 1) was added, shaken for 15 min, centrifuged, and dried at 60° C. for 12 h to obtain product 2 for later use;

[0067] 3) Take 5 g of the product 2 obtained in step 2), add 30 g of carvacrol, stir for 20 min, pressurize to 2 MPa, filter 6 times, centrifuge, and dry at 60° C. for 12 h to obtain modified diatomaceous earth A.

[0068] Preparation Example 7

[0069] Modified diatomaceous earth B, the specific implementation method is the same as modified diatomaceous earth A, except that the mass of guanidine hydrochloride in step 2) is replaced with 0.8 g.

[0070] Preparation Example 8

[0071] Modified diatomite C, the specific implementation method is the same as modified diatomite A, except that the mass of guanidine hydrochloride in step 2) is replaced with 3.5 g.

[0072] Example 1

[0073] A medicinal fertilizer composite carrier with a controlled loss and sustained release function comprises the following raw materials in parts by weight: 90 parts of an amphiphilic block copolymer A, 7.5 parts of attapulgite, 5 parts of fly ash and 10 parts of modified diatomaceous earth A.

[0074] The preparation method of the medicine-fertilizer composite carrier with controlled-release slow-release function in this embodiment comprises the following steps:

[0075] The amphiphilic block copolymer A, attapulgite, fly ash and modified diatomaceous earth A were placed in a reactor, stirred for 1.5 hours, and ground for 30 minutes to obtain a drug-fertilizer composite carrier with controlled loss and slow release function.

[0076] Example 2

[0077] A medicine-fertilizer composite carrier with a controlled-loss and slow-release function comprises the following raw materials, measured by weight: 90 parts of an amphiphilic block copolymer A, 5 parts of attapulgite, 3 parts of fly ash, and 5 parts of modified diatomaceous earth A.

[0078] The preparation method of the medicine-fertilizer composite carrier with controlled-release slow-release function in this embodiment comprises the following steps:

[0079] The amphiphilic block copolymer A, attapulgite, fly ash and modified diatomaceous earth A are placed in a reactor, stirred for 1 hour, and ground for 20 minutes to obtain a drug-fertilizer composite carrier with controlled loss and slow release function.

[0080] Example 3

[0081] A medicine-fertilizer composite carrier with a controlled-loss and slow-release function comprises the following raw materials, measured by weight: 90 parts of an amphiphilic block copolymer A, 10 parts of attapulgite, 7 parts of fly ash, and 15 parts of modified diatomaceous earth A.

[0082] The preparation method of the medicine-fertilizer composite carrier with controlled-release slow-release function in this embodiment comprises the following steps:

[0083] The amphiphilic block copolymer A, attapulgite, fly ash and modified diatomaceous earth A are placed in a reactor, stirred for 2 hours, and ground for 40 minutes to obtain a drug-fertilizer composite carrier with controlled loss and slow release function.

[0084] Example 4

[0085] A medicine-fertilizer composite carrier with a controlled-loss and slow-release function comprises the following raw materials, measured by weight: 80 parts of an amphiphilic block copolymer A, 6 parts of attapulgite, 4 parts of fly ash, and 10 parts of modified diatomaceous earth A.

[0086] The preparation method of the medicine-fertilizer composite carrier with controlled-release slow-release function in this embodiment is the same as that in Example 1.

[0087] Example 5

[0088] A medicine-fertilizer composite carrier with a controlled-loss and slow-release function comprises the following raw materials, measured by weight: 100 parts of an amphiphilic block copolymer A, 9 parts of attapulgite, 6 parts of fly ash, and 10 parts of modified diatomaceous earth A.

[0089] The preparation method of the medicine-fertilizer composite carrier with controlled-release slow-release function in this embodiment is the same as that in Example 1.

[0090] Example 6

[0091] The present invention provides a medicine-fertilizer composite carrier with a controlled-loss sustained-release function and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the amphiphilic block copolymer A is replaced by an amphiphilic block copolymer B in equal amounts.

[0092] Example 7

[0093] The present invention provides a medicine-fertilizer composite carrier with a controlled-loss sustained-release function and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the amphiphilic block copolymer A is replaced by an amphiphilic block copolymer C in equal amounts.

[0094] Example 8

[0095] The present invention provides a medicine-fertilizer composite carrier with a controlled-loss sustained-release function and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the amphiphilic block copolymer A is replaced by an amphiphilic block copolymer D in equal amounts.

[0096] Example 9

[0097] The present invention provides a medicine-fertilizer composite carrier with controlled-loss sustained-release function and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the amphiphilic block copolymer A is replaced by an equal amount of the amphiphilic block copolymer E.

[0098] Example 10

[0099] The present invention provides a medicine-fertilizer composite carrier with controlled-loss and sustained-release function and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the modified diatomaceous earth B replaces the modified diatomaceous earth A in equal amounts.

[0100] Embodiment 11

[0101] The present invention provides a medicine-fertilizer composite carrier with controlled-loss and sustained-release function and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that modified diatomaceous earth C replaces modified diatomaceous earth A in equal amounts.

[0102] Example 12

[0103] The present invention provides a medicine-fertilizer composite carrier with controlled-loss sustained-release function and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the amphiphilic block copolymer A is replaced by an equal amount of polyethylene glycol-polylactic acid.

[0104] The synthetic method of polyethylene glycol-polylactic acid comprises the following steps:

[0105] Mix 50 g of L-lactide, 15 g of polyethylene glycol and 1.5 g of stannous octoate, stir for 10 min, heat to 120°C under a nitrogen atmosphere and react for 2 h, add 40 ml of chloroform and 100 ml of ether, filter, take the precipitate, and dry at 60°C for 12 h to obtain polyethylene glycol-polylactic acid.

[0106] Comparative Example 1

[0107] This comparative example provides a drug-fertilizer composite carrier with controlled loss and sustained release function and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that diatomaceous earth is used instead of modified diatomaceous earth A.

[0108] Performance Testing

[0109] The sustained-release effects of the drug-fertilizer composite carriers with controlled-release slow-release functions described in Examples 1-12 and Comparative Example 1 were tested, and the test results are shown in Table 1.

[0110] In parts by weight, 3 parts of the carriers prepared in the above embodiments and comparative examples were mixed with 6 parts of thiamethoxam and 100 parts of fertilizer 15-5-10, and their sustained-release effects were tested according to standard HG / T 5519-2019. The sustained-release effect of the drug-fertilizer composite carrier under this system was determined according to the obtained nitrogen dissolution rate. The smaller the nitrogen dissolution rate, the better the sustained-release effect of the drug-fertilizer composite carrier.

[0111] Table 1

[0112] Group Nitrogen dissolution rate / % Example 1 50.3 Example 2 51.5 Example 3 51.8 Example 4 52.2 Example 5 52.1 Example 6 70.8 Example 7 70.2 Example 8 71.2 Example 9 72.2 Example 10 65.2 Embodiment 11 64.9 Example 12 95.2 Comparative Example 1 93.4

[0113] As can be seen from the data in Table 1, the composite carriers of medicine and fertilizer in Examples 1-5 of the present invention all have the characteristics of a smaller nitrogen dissolution rate, i.e., a better sustained-release effect. Among them, Examples 6-9 change the ratio between the main components of the amphiphilic block copolymer during synthesis, such as the modification ratio of polyphospholipids and triphenylphosphine and keto acid structures, so that the stability and antioxidant properties of the amphiphilic block copolymers are reduced, thereby resulting in a decrease in the sustained-release effect of the composite carrier of medicine and fertilizer; Examples 10-11 change the modification ratio of guanidine salts to diatomaceous earth, so that the stability and antibacterial properties of diatomaceous earth are weakened, thereby resulting in a decrease in the sustained-release effect of the mixed carrier of medicine and fertilizer; Example 12 and Comparative Example 1 respectively use polyethylene glycol-polylactic acid and diatomaceous earth to replace amphiphilic block copolymer A and modified diatomaceous earth A, and the test finds that the sustained-release effect of the prepared composite carrier of medicine and fertilizer shows poor results.

[0114] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A medicine-fertilizer composite carrier with controlled-release slow-release function, characterized in that: The raw materials include the following in parts by weight: 80-100 parts of amphiphilic block copolymer, 5-10 parts of natural minerals, 3-7 parts of power plant waste, and 5-15 parts of modified diatomaceous earth; The preparation method of the amphiphilic block copolymer comprises the following steps: (1) Mix tert-butyl N-(2,3-dihydroxypropyl)carbamate, tetrahydrofuran and triethylamine, stir, add methacryloyl chloride dropwise at -5-0°C, wait for the temperature to return to room temperature, stir for 23-25 ​​hours, filter, rotary evaporate, wash, and dry to obtain reaction product 1 for later use; (2) The reaction product 1 of step (1), triethylamine and tetrahydrofuran are mixed, an inert gas is introduced at -15 to -5°C, the mixture is stirred, 2-chloro-2-oxo-1,3,2-dioxaphospholane and tetrahydrofuran are added, the mixture is stirred, filtered, the filtrate is collected, washed, and rotary evaporated to obtain the reaction product 2 for later use; (3) Lactide, polyethylene glycol and stannous octoate are mixed, stirred, heated to 110-130°C under an inert atmosphere for reaction for 1.5-2.5 hours, chloroform and ether are added, filtered, the precipitate is collected, and dried to obtain polyethylene glycol-polylactic acid for later use; (4) Take the polyethylene glycol-polylactic acid prepared in step (3), add the reaction product 2 prepared in step (2), stannous octoate and tetrahydrofuran, introduce an inert gas, react at 30-50° C. for 1-3 h, add ether, filter, and dry to obtain the reaction product 3 for later use; (5) dissolving 2-mercaptothiophene and methyl 4'-pyridyl-4-benzoate in toluene, heating to reflux, rotary evaporation, adding sodium hydroxide solution, heating to reflux, cooling to room temperature, adding acetic acid solution dropwise until white precipitate appears, filtering, washing, and drying to obtain reaction product 4 for later use; (6) Take the reaction product 4 of step (5), add triphenyl phosphate, ketoic acid, toluene and n-butanol, heat to reflux, filter, wash and dry to obtain the reaction product 5 for use; (7) Take the reaction product 3 of step (4), add the reaction product 5 of step (6), dichloromethane and trifluoroacetic acid, seal, stir for 8-10 hours, add petroleum ether, take the precipitate, and dry to obtain an amphiphilic block copolymer; The mass ratio of the reaction product 1 to 2-chloro-2-oxo-1,3,2-dioxaphospholane in step (2) is (1.6-2.6):1; the mass ratio of the polyethylene glycol-polylactic acid to the reaction product 2 in step (4) is 1:(0.2-0.3); In step (7), the mass ratio of reaction product 3 to reaction product 5 is 1:(0.03-0.07); The natural mineral is attapulgite; The power plant waste is fly ash; The preparation method of the modified diatomite comprises the following steps: 1) adding diatomaceous earth to deionized water, adding anionic surfactant, adjusting pH to 1-2, stirring, standing, filtering, washing, and drying to obtain product 1 for later use; 2) guanidine hydrochloride, sodium tripolyphosphate and deionized water are mixed, stirred, and the product 1 of step 1) is added, shaken, centrifuged, and dried to obtain product 2 for later use; 3) taking the product 2 of step 2), adding carvacrol, stirring, filtering under pressure, centrifuging, and drying to obtain modified diatomaceous earth; In the step 2), the mass ratio of the product 1 to guanidine hydrochloride is 1:(0.2-0.6).

2. The medicine-fertilizer composite carrier with controlled-release slow-release function according to claim 1, characterized in that: In step (3) of the method for preparing the amphiphilic block copolymer, the lactide is L-lactide; and the number average molecular weight of the polyethylene glycol is 4000-6000.

3. A method for preparing a medicine-fertilizer composite carrier with controlled-release slow-release function according to any one of claims 1 to 2, characterized in that: The following steps are involved: The amphiphilic block copolymer, natural minerals, power plant waste and modified diatomaceous earth are placed in a reactor, stirred for 1-2 hours, and ground for 20-40 minutes to obtain a drug-fertilizer composite carrier with controlled loss and slow release function.