Preparation method of spirodiclofen and oligosaccharin complex soluble concentrate

Abstract

The present application relates to the technical field of pesticide preparation, in particular to a preparation method of a soluble solution of propiconazole and oligosaccharin compound, which is realized through the following steps: firstly, a mixed solvent is prepared; then, propiconazole technical material is dissolved in the mixed solvent after ultrasonic and nanometer grinding treatment, to obtain a propiconazole solution; then, oligosaccharin is added to prepare a compound stock solution through gradient stirring; subsequently, lentinan, a surfactant, a composite stabilizer and other additives are sequentially added, and the final product is obtained through secondary filtration and constant volume. The present application solves the problems of poor lipid-water compatibility, insufficient extreme environmental stability and weak crop stress resistance adaptation of the existing compound preparation, realizes the synergy of "anti-fungus-anti-virus-cold resistance-lodging resistance-quality improvement and yield increase", is especially suitable for cold rice, tobacco and other crops, and is compatible with the existing production line, so it has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of pesticide formulation technology, and in particular to a method for preparing a soluble concentrate of propanetriol and oligosaccharide. Background Technology

[0002] Propylene ester, a highly efficient isomer of propyl dihydrojasmonic acid, is a novel jasmonic acid plant growth regulator with significant application potential in the agricultural field. Its core advantage lies in its ability to precisely mimic the endogenous jasmonic acid signaling pathway in plants. It not only significantly promotes uniform fruit coloring and sugar accumulation but also induces cold resistance, drought resistance, and broad-spectrum disease resistance in crops, demonstrating outstanding performance in improving the quality and yield of fruits, vegetables, and grains. However, propylene ester has significant limitations when used alone: ​​firstly, the cost per unit of active ingredient is relatively high, which can easily increase planting costs with large-scale application; secondly, its disease resistance spectrum is relatively narrow, with limited control effects against fungal diseases (such as rice powdery mildew); and thirdly, long-term single application can easily lead to a "diminishing effect" in crops, making it difficult to sustain its regulatory role.

[0003] Oligosaccharides (such as chitosan oligosaccharides and glucosamine oligosaccharides), as natural plant immune inducers, possess both environmental friendliness and multifunctional advantages due to their origin from renewable resources such as shrimp and crab shells. On the one hand, they can activate the crop's own defense system, inducing the synthesis of disease-resistant substances such as phytoalexins and pathogenesis-related proteins (PR proteins), and have control effects against fungal, bacterial, and viral diseases. On the other hand, they can improve the structure of soil microbial communities, promote crop root development, and enhance nutrient absorption capacity. However, oligosaccharides also have shortcomings when used alone: ​​their effects are slow, and under adverse conditions such as low temperature and drought, their growth-promoting and disease-resistant effects are easily inhibited, making it difficult to meet the emergency stress resistance needs of crops.

[0004] Currently, although single formulations of propanetriol or oligosaccharides have appeared on the market, and a few products attempt to physically mix the two, existing compounding technologies suffer from four major defects that severely restrict their application:

[0005] Therefore, based on the relevant technologies mentioned above, there is an urgent need to develop a compound soluble concentrate with a reasonable formulation, stable process, and the ability to fully leverage the synergistic effect of propanetriol and oligosaccharides. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a method for preparing a soluble concentrate of propanetriol and oligosaccharides, in order to solve the problem that in the prior art, the simple physical mixing of propanetriol and oligosaccharides may lead to instability of the formulation due to compatibility issues (such as precipitation, flocculation, decomposition, etc.), thus failing to fully exert the synergistic effect of the two.

[0007] To achieve the above objectives, the present invention provides a method for preparing a soluble concentrate composed of propanetriol and oligosaccharides.

[0008] A method for preparing a soluble concentrate composed of propanetriol and oligosaccharides includes the following steps:

[0009] Step S1. Add the main solvent and co-solvent to the reactor equipped with an anchor-type stirring device (stirring paddle material is 304 stainless steel), control the temperature inside the reactor to 20-30℃, the stirring speed to 200-400r / min, stir for 15-25min until the system is clear and transparent (transmittance ≥98%), and obtain the mixed solvent.

[0010] Step S2. Slowly add propylene glycol technical grade (purity ≥98%, melting point 182-184℃, boiling point 350℃±5℃) to the mixed solvent from step S1 at a mass ratio of 0.1-5:95-99.9 (propylene glycol: mixed solvent). Maintain the reactor temperature at 25℃ and the stirring speed at 300 r / min. Simultaneously, turn on a 300-400W ultrasonic device (ultrasonic frequency 20kHz) for 10-15 min to break up the aggregated state of the technical grade. Continue stirring for 20-40 min, then use a horizontal sand mill (zirconium) to process the mixture. The beads (with a particle size of 0.1-0.3 mm) were nano-ground for 15-25 min to control the particle size of propylene glycol D90 ≤ 1 μm. After grinding, high performance liquid chromatography (HPLC) was used for detection (chromatographic column: C18 column 250 mm × 4.6 mm, 5 μm; mobile phase: methanol-water = 80:20, v / v; flow rate 1.0 mL / min; detection wavelength 230 nm; column temperature 30 ℃) until the chromatographic peak area stabilized (RSD < 1%) and there were no impurity peaks, confirming that propylene glycol was completely dissolved and a propylene glycol solution was obtained.

[0011] Step S3. Add oligosaccharide combination to the propylene glycol solution, keep the reactor temperature at 25℃, and use a gradient stirring process: first stir at 200 r / min for 5 min, then gradually increase the speed to 400 r / min at 50 r / min (the speed increase process lasts for 15 min), and then maintain the stirring speed at 400 r / min for 30-60 min. Detect the absorbance using a UV spectrophotometer (detection wavelength 205 nm) until the absorbance stabilizes (fluctuation range ≤ ±0.02) and there are no suspended particles (particle size analyzer D90 < 5 μm), to obtain the compound stock solution;

[0012] Step S4. Add lentinan, surfactant, composite stabilizer, antifreeze, defoamer and stress-resistant agent to the compound stock solution in sequence. After each addition of an auxiliary agent, keep the stirring speed at 300 r / min and stir for 10-15 min to ensure uniform mixing and obtain a homogeneous mixture.

[0013] Step S5. Adjust the pH of the homogeneous mixture to 5.0-7.0 using a pH adjuster. During the adjustment process, use a precision pH meter (accuracy ±0.01) to monitor in real time and maintain a stirring speed of 200 r / min to avoid excessively high local acid and alkali concentrations. After adjustment, continue stirring for 8-15 min. After adjustment, let it stand at 25℃ for 30 min to precipitate, and then perform secondary filtration. First, filter through a 0.45 μm polyvinylidene fluoride (PVDF) filter membrane, and then filter through a 0.1 μm PVDF filter membrane to remove small impurities (such as undissolved additive particles) to obtain the reconstituted solution.

[0014] Step S6. Add deionized water (conductivity ≤10μS / cm) to the reconstituted solution to bring the total mass of the final formulation to 100kg. Maintain a stirring speed of 200r / min and stir for 60-90min to ensure the system is fully mixed. Then filter the solution using a 0.1μm polyvinylidene fluoride (PVDF) membrane (pore size uniformity RSD <5%) to remove minute impurities (such as undissolved adjuvant particles) and obtain a clear and transparent soluble formulation of propylene glycol and oligosaccharide.

[0015] Preferably, the mass ratio of the main solvent to the co-solvent in step S1 is 10-30:5-15;

[0016] The main solvent is composed of ethanol, propylene glycol, and diethylene glycol monomethyl ether;

[0017] The mass ratio of ethanol, propylene glycol and diethylene glycol monomethyl ether in the main solvent is 3:2:1;

[0018] The purity of the ethanol is ≥95%, the purity of the propylene glycol is ≥99%, the purity of the diethylene glycol monomethyl ether is ≥99%, and the purity of the N-methylpyrrolidone is ≥99%.

[0019] The co-solvent is N-methylpyrrolidone.

[0020] The mass ratio of the mixed solvent to the propylene glycol technical grade is 95-99.9:0.1-5.

[0021] Preferably, during the grinding process in step S2 using the horizontal sand mill, the grinding chamber temperature is controlled at 25-30℃ to avoid degradation of propylene glycol due to high temperature.

[0022] Preferably, the oligosaccharide combination in step S3 is composed of carboxymethyl chitosan oligosaccharide and amino oligosaccharide in a mass ratio of 1:1-2 (the degree of substitution of carboxymethyl chitosan oligosaccharide is 0.8-1.2, molecular weight is 1000-3000 Da, and purity is ≥95%; the degree of substitution of amino oligosaccharide is 0.6-1.0, molecular weight is 1500-3000 Da, and purity is ≥95%); the mass ratio of propylene glycol ester solution to oligosaccharide combination is 90-98.9:1.1-10.

[0023] Preferably, the mass ratio of the surfactant to the compound stock solution in step S4 is 3-8:92-97;

[0024] Preferably, in step S4, the mass ratio of the compound stock solution, lentinan, surfactant, composite stabilizer, antifreeze, defoamer and stress-resistant agent is 92-97:0.5-2:3-8:0.2-0.4:7-10:0.08-0.15:2.0-2.8.

[0025] Preferably, the lentinan described in step S4 is dissolved in deionized water (mass ratio 1:5) to form a lentinan aqueous solution before use, and then the compound stock solution is added to ensure uniform dispersion.

[0026] The surfactant described in step S4 is composed of Tween 80 and sodium dodecylbenzenesulfonate;

[0027] The composite stabilizer is composed of 2,6-di-tert-butyl-p-cresol and vitamin E;

[0028] The antifreeze is propylene glycol;

[0029] The defoamer is polydimethylsiloxane;

[0030] The stress-resistant additive is composed of polyethylene glycol 6000 and hydroxypropyl methylcellulose.

[0031] Preferably, the mass ratio of Tween 80 to sodium dodecylbenzenesulfonate in the surfactant is 3:1-4:1;

[0032] The mass ratio of 2,6-di-tert-butyl-p-cresol to vitamin E in the composite stabilizer is 1:1.

[0033] The mass ratio of polyethylene glycol 6000 to hydroxypropyl methylcellulose in the stress-resistant additive is 3:1.

[0034] Preferably, the filter membrane used for secondary filtration in step S5 needs to be soaked in deionized water for 10 minutes before use to avoid introducing impurities from the filter membrane into the formulation.

[0035] Preferably, the pH adjuster in step S5 is a 10% citric acid aqueous solution or a 10% sodium hydroxide aqueous solution;

[0036] The 10% citric acid aqueous solution is obtained by mixing citric acid and deionized water at a mass ratio of 1:9;

[0037] The 10% sodium hydroxide aqueous solution is obtained by mixing sodium hydroxide and deionized water at a mass ratio of 1:9.

[0038] The beneficial effects of this invention are:

[0039] The soluble concentrate of propylene glycol and oligosaccharides described in this invention and its preparation method have several outstanding advantages: By combining an ethanol-propylene glycol-diethylene glycol monomethyl ether mixed solvent with carboxymethylated chitosan oligosaccharides and amino oligosaccharides, the lipid-water compatibility problem between propylene glycol and oligosaccharides is solved; there is no stratification or crystallization when stored at -20℃, and the degradation rate of effective components is low when stored at 54℃; combined with a two-stage filtration process, the shelf life is extended to more than 24 months; relying on the ternary compound of propylene glycol + oligosaccharides + lentinan and stress-resistant adjuvants, a synergistic effect of "growth promotion + disease resistance + cold resistance + lodging resistance" is achieved, improving the low-temperature germination rate and stem resistance of cold-region rice. This product effectively reduces lodging area and achieves a 72.2%-74.4% control effect against rice powdery mildew. It also increases yield per hectare by 12.9%-13.9% compared to the control group, and can control viral diseases. The particle size of propylene glycol is controlled to D90≤1μm through ultrasonic-nano-grinding, and combined with specific surfactants to improve crop absorption efficiency without phytotoxicity. The selected raw materials are low in toxicity and easily degradable, ensuring crop and ecological safety. Furthermore, the preparation process is compatible with existing pesticide production lines, requiring no additional equipment. Although carboxymethylated chitosan oligosaccharides are slightly more expensive, they can reduce the number of applications, lower overall planting costs, and are suitable for various crops in cold regions, demonstrating significant potential for widespread application. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0041] The properties of some of the raw materials used in the embodiments of this invention are as follows:

[0042] Propylene glycol technical grade: purity ≥98%, melting point 182-184℃, boiling point 350℃±5℃, industrial grade;

[0043] Carboxymethylated chitosan oligosaccharide: degree of substitution 0.8-1.2, molecular weight 1000-3000 Da, purity ≥95%, prepared by modification via chloroacetic acid-isopropanol system, food grade;

[0044] Ethanol: Purity ≥ 95%, industrial grade;

[0045] Propylene glycol: purity ≥99%, with both solvent and antifreeze functions, industrial grade;

[0046] Diethylene glycol monomethyl ether: purity ≥99%, low-temperature co-solvent, industrial grade;

[0047] N-Methylpyrrolidone (NMP): Purity ≥99%, cosolvent, industrial grade;

[0048] Tween 80 (polyoxyethylene sorbitan monooleate): industrial grade, surfactant;

[0049] SDBS (Sodium Dodecylbenzene Sulfonate): Industrial grade, with an effective sodium dodecylbenzene sulfonate content ≥95%;

[0050] BHT (2,6-di-tert-butyl-p-cresol): Purity ≥99%;

[0051] Vitamin E: Purity ≥ 98%;

[0052] Polyethylene glycol 6000 (PEG-6000): Purity ≥99%;

[0053] Citric acid: food grade, purity ≥99%;

[0054] Sodium hydroxide: analytical grade, purity ≥96%;

[0055] Deionized water: self-made, conductivity ≤10μS / cm, used for volume adjustment of formulations and dissolution of raw materials.

[0056] Example 1: A method for preparing a soluble concentrate composed of propanetriol and oligosaccharides, comprising the following steps:

[0057] S1. Ethanol, propylene glycol, and diethylene glycol monomethyl ether are mixed in a mass ratio of 3:2:1 to obtain the main solvent. N-methylpyrrolidone is used as a co-solvent. The main solvent and co-solvent are added to a reactor equipped with an anchor-type stirring device (stirring paddle material is 304 stainless steel). The temperature inside the reactor is controlled at 20℃, the stirring speed is 200r / min, and the stirring is carried out for 15min until the system is clear and transparent (transmittance ≥98%), to obtain a mixed solvent. The mass ratio of the main solvent to the co-solvent is 10:5, the purity of ethanol is ≥95%, the purity of propylene glycol is ≥99%, the purity of diethylene glycol monomethyl ether is ≥99%, and the purity of N-methylpyrrolidone is ≥99%.

[0058] S2. Slowly add propylene glycol technical grade (purity ≥98%, melting point 182-184℃, boiling point 350℃±5℃) to the mixed solvent at a mass ratio of 0.1:95 (propylene glycol: mixed solvent). Maintain the reactor temperature at 25℃ and the stirring speed at 300 r / min. Simultaneously, turn on a 300W ultrasonic device (ultrasonic frequency 20kHz) for 10 min to break up the aggregated state of the technical grade. Continue stirring for 20 min, then perform nano-grinding for 15 min using a horizontal sand mill (zirconium bead particle size 0.1-0.3mm) to control the propylene glycol particle size D90≤1μm. After grinding, use high performance liquid chromatography (HPLC) to analyze the results. HPLC detection was performed (column: C18 column 250mm×4.6mm, 5μm; mobile phase: methanol-water = 80:20, v / v; flow rate 1.0mL / min; detection wavelength 230nm; column temperature 30℃) until the peak area stabilized (RSD < 1%) and no impurity peaks were observed, confirming complete dissolution of propylene glycol ester and obtaining a propylene glycol ester solution. In this process, after adding propylene glycol ester technical grade to the mixed solvent, the mixture was first sonicated and then stirred until the propylene glycol ester technical grade was completely dissolved, yielding the propylene glycol ester solution. During horizontal grinding, the grinding chamber temperature was controlled at 25℃ to avoid degradation of propylene glycol ester due to high temperature.

[0059] S3. Add the oligosaccharide combination to the propylene glycol solution, maintain the reactor temperature at 25℃, and use a gradient stirring process: first stir at 200 r / min for 5 min, then gradually increase the speed to 400 r / min at 50 r / min (the rate increase process lasts for 15 min), and then maintain stirring at 400 r / min for 30 min. Detect the absorbance using a UV spectrophotometer (detection wavelength 205 nm) until the absorbance stabilizes (fluctuation range ≤ ±0.02) and there are no suspended particles. The particles (D90 < 5 μm as determined by particle size analyzer) were used to obtain a compound stock solution. The oligosaccharide combination consisted of carboxymethyl chitosan oligosaccharide and amino oligosaccharide in a mass ratio of 1:1. The degree of substitution of carboxymethyl chitosan oligosaccharide was 0.8-1.2, the molecular weight was 1000-3000 Da, and the purity was ≥95%. The degree of substitution of amino oligosaccharide was 0.6-1.0, the molecular weight was 1500-3000 Da, and the purity was ≥95%. The mass ratio of propylene glycol ester solution to oligosaccharide combination was 90:1.1.

[0060] S4. To the compound stock solution, add lentinan, surfactant, composite stabilizer, antifreeze, defoamer, and stress-resistant agent sequentially. After adding each agent, maintain a stirring speed of 300 rpm and stir for 10 minutes to ensure uniform mixing and obtain a homogeneous mixture. Before use, dissolve the lentinan in deionized water (mass ratio 1:5) to prepare a lentinan aqueous solution before adding it to the compound stock solution, ensuring uniform dispersion. The mass ratio of the compound stock solution, lentinan, surfactant, composite stabilizer, antifreeze, defoamer, and stress-resistant agent is 92:0. The surfactant is obtained by mixing Tween 80 and sodium dodecylbenzenesulfonate in a mass ratio of 3:1. The composite stabilizer is composed of 2,6-di-tert-butyl-p-cresol and vitamin E. The antifreeze agent is propylene glycol. The defoamer is polydimethylsiloxane. The stress-resistant agent is composed of polyethylene glycol 6000 and hydroxypropyl methylcellulose. The mass ratio of 2,6-di-tert-butyl-p-cresol and vitamin E in the composite stabilizer is 1:1. The mass ratio of polyethylene glycol 6000 and hydroxypropyl methylcellulose in the stress-resistant agent is 3:1.

[0061] S5. Adjust the pH of the homogeneous mixture to 5.0 using a 10% citric acid aqueous solution. During the adjustment process, use a precision pH meter (accuracy ±0.01) to monitor in real time and maintain a stirring speed of 200 r / min to avoid excessively high local acid or alkali concentrations. After adjustment, continue stirring for 8 min. After adjustment, allow the mixture to stand at 25℃ for 30 min to settle, and then perform secondary filtration. First, filter through a 0.45 μm polyvinylidene fluoride (PVDF) membrane, and then filter through a 0.1 μm PVDF membrane to remove small impurities (such as undissolved additive particles) to obtain the reconstituted solution. The filter membrane used for secondary filtration should be soaked in deionized water for 10 min before use to avoid introducing impurities into the formulation. The 10% citric acid aqueous solution is obtained by mixing citric acid and deionized water at a mass ratio of 1:9.

[0062] S6. Add deionized water (conductivity ≤10μS / cm) to the reconstituted solution to bring the total mass of the final formulation to 100kg. Maintain a stirring speed of 200r / min and stir for 60min to ensure the system is fully mixed. Then filter the solution using a 0.1μm polyvinylidene fluoride (PVDF) filter membrane (pore size uniformity RSD <5%) to remove minute impurities (such as undissolved adjuvant particles) and obtain a clear and transparent soluble formulation of propylene glycol and oligosaccharide.

[0063] Example 2: A method for preparing a soluble concentrate composed of propanetriol and oligosaccharides, comprising the following steps:

[0064] S1. Ethanol, propylene glycol, and diethylene glycol monomethyl ether are mixed in a mass ratio of 3:2:1 to obtain the main solvent. N-methylpyrrolidone is used as a co-solvent. The main solvent and co-solvent are added to a reactor equipped with an anchor-type stirring device (stirring paddle material is 304 stainless steel). The temperature inside the reactor is controlled at 24℃, the stirring speed is 250r / min, and the stirring is carried out for 19min until the system is clear and transparent (transmittance ≥98%), to obtain a mixed solvent. The mass ratio of the main solvent to the co-solvent is 20:10, the purity of ethanol is ≥95%, the purity of propylene glycol is ≥99%, the purity of diethylene glycol monomethyl ether is ≥99%, and the purity of N-methylpyrrolidone is ≥99%.

[0065] S2. Slowly add propylene glycol technical grade (purity ≥98%, melting point 182-184℃, boiling point 350℃±5℃) to the mixed solvent at a mass ratio of 3:97 (propylene glycol: mixed solvent). Maintain the reactor temperature at 25℃ and the stirring speed at 300 r / min. Simultaneously, turn on a 330W ultrasonic device (ultrasonic frequency 20kHz) for 12 min to disrupt the aggregated state of the technical grade. Continue stirring for 25 min, then perform nano-grinding for 18 min using a horizontal sand mill (zirconium bead particle size 0.1-0.3mm) to control the propylene glycol particle size D90≤1μm. After grinding, perform high performance liquid chromatography. (HPLC) detection (chromatographic column: C18 column 250mm×4.6mm, 5μm; mobile phase: methanol-water = 80:20, v / v; flow rate 1.0mL / min; detection wavelength 230nm; column temperature 30℃) until the chromatographic peak area stabilizes (RSD < 1%) and there are no impurity peaks, confirming that propylene glycol is completely dissolved, and a propylene glycol solution is obtained. In this case, after adding propylene glycol technical material to the mixed solvent, it is first ultrasonically treated and then stirred until the propylene glycol technical material is completely dissolved to obtain a propylene glycol solution. In this case, when grinding with a horizontal sand mill, the grinding chamber temperature is controlled at 26℃ to avoid degradation of propylene glycol due to high temperature.

[0066] S3. Add the oligosaccharide combination to the propylene glycol solution, maintain the reactor temperature at 25℃, and use a gradient stirring process: first stir at 200 r / min for 5 min, then gradually increase the speed to 400 r / min at 50 r / min (the rate increase process lasts for 15 min), and then maintain stirring at 400 r / min for 40 min. Detect the absorbance using a UV spectrophotometer (detection wavelength 205 nm) until the absorbance stabilizes (fluctuation range ≤ ±0.02) and no suspended particles are found. The particles (D90 < 5 μm as determined by particle size analyzer) were used to obtain a compound stock solution. The oligosaccharide combination consisted of carboxymethyl chitosan oligosaccharide and amino oligosaccharide in a mass ratio of 1:1.2. The degree of substitution of carboxymethyl chitosan oligosaccharide was 0.8-1.2, the molecular weight was 1000-3000 Da, and the purity was ≥95%. The degree of substitution of amino oligosaccharide was 0.6-1.0, the molecular weight was 1500-3000 Da, and the purity was ≥95%. The mass ratio of propylene glycol ester solution to oligosaccharide combination was 93:3.

[0067] S4. Add lentinan, surfactant, composite stabilizer, antifreeze, defoamer, and stress-resistant agent sequentially to the compound stock solution. After adding each agent, maintain a stirring speed of 300 r / min and stir for 12 min to ensure uniform mixing and obtain a homogeneous mixture. Before use, dissolve the lentinan in deionized water (mass ratio 1:5) to form a lentinan aqueous solution, then add it to the compound stock solution to ensure uniform dispersion. The mass ratio of the compound stock solution, lentinan, surfactant, composite stabilizer, antifreeze, defoamer, and stress-resistant agent is 93:0. The surfactant is obtained by mixing Tween 80 and sodium dodecylbenzenesulfonate in a mass ratio of 3.2:1. The composite stabilizer is composed of 2,6-di-tert-butyl-p-cresol and vitamin E. The antifreeze agent is propylene glycol. The defoamer is polydimethylsiloxane. The stress-resistant agent is composed of polyethylene glycol 6000 and hydroxypropyl methylcellulose. The mass ratio of 2,6-di-tert-butyl-p-cresol and vitamin E in the composite stabilizer is 1:1. The mass ratio of polyethylene glycol 6000 and hydroxypropyl methylcellulose in the stress-resistant agent is 3:1.

[0068] S5. Adjust the pH of the homogeneous mixture to 5.5 using a 10% sodium hydroxide aqueous solution. During the adjustment process, use a precision pH meter (accuracy ±0.01) to monitor in real time and maintain a stirring speed of 200 r / min to avoid excessively high local acid and alkali concentrations. After adjustment, continue stirring for 10 min. After adjustment, let it stand at 25℃ for 30 min to precipitate, and then perform secondary filtration. First, filter through a 0.45 μm polyvinylidene fluoride (PVDF) filter membrane, and then filter through a 0.1 μm PVDF filter membrane to remove small impurities (such as undissolved additive particles) to obtain the reconstituted solution. The filter membrane of the secondary filtration should be soaked in deionized water for 10 min before use to avoid impurities in the filter membrane being introduced into the formulation. The 10% sodium hydroxide aqueous solution is obtained by mixing sodium hydroxide and deionized water at a mass ratio of 1:9.

[0069] S6. Add deionized water (conductivity ≤10μS / cm) to the reconstituted solution to bring the total mass of the final formulation to 100kg. Maintain a stirring speed of 200r / min and stir for 70min to ensure the system is thoroughly mixed. Then filter the solution using a 0.1μm polyvinylidene fluoride (PVDF) filter membrane (pore size uniformity RSD <5%) to remove minute impurities (such as undissolved adjuvant particles) and obtain a clear and transparent soluble formulation of propylene glycol and oligosaccharide compound.

[0070] Example 3: A method for preparing a soluble concentrate composed of propanetriol and oligosaccharides, comprising the following steps:

[0071] S1. Ethanol, propylene glycol, and diethylene glycol monomethyl ether are mixed in a mass ratio of 3:2:1 to obtain the main solvent. N-methylpyrrolidone is used as a co-solvent. The main solvent and co-solvent are added to a reactor equipped with an anchor-type stirring device (stirring paddle material is 304 stainless steel). The temperature inside the reactor is controlled at 26℃, the stirring speed is 300r / min, and the stirring is carried out for 21min until the system is clear and transparent (transmittance ≥98%), to obtain a mixed solvent. The mass ratio of the main solvent to the co-solvent is 25:12, the purity of ethanol is ≥95%, the purity of propylene glycol is ≥99%, the purity of diethylene glycol monomethyl ether is ≥99%, and the purity of N-methylpyrrolidone is ≥99%.

[0072] S2. Propylene ester technical grade (purity ≥98%, melting point 182-184℃, boiling point 350℃±5℃) was slowly added to the mixed solvent at a mass ratio of 4:98 (propylene ester: mixed solvent). The reactor temperature was maintained at 25℃, and the stirring speed at 300 r / min. Simultaneously, a 360W ultrasonic device (ultrasonic frequency 20kHz) was used to treat the mixture for 14 min to disrupt the aggregated state of the technical grade. After stirring for another 30 min, the mixture was nano-milled for 20 min using a horizontal sand mill (zirconium bead size 0.1-0.3 mm) to control the propylene ester particle size D90 ≤ 1 μm. The resulting product was then subjected to high-performance liquid chromatography (HPLC). (HPLC) detection (chromatographic column: C18 column 250mm×4.6mm, 5μm; mobile phase: methanol-water = 80:20, v / v; flow rate 1.0mL / min; detection wavelength 230nm; column temperature 30℃) until the chromatographic peak area stabilizes (RSD < 1%) and there are no impurity peaks, confirming that propylene glycol is completely dissolved, and a propylene glycol solution is obtained. In this case, after adding propylene glycol technical material to the mixed solvent, it is first ultrasonically treated and then stirred until the propylene glycol technical material is completely dissolved to obtain a propylene glycol solution. In this case, when grinding with a horizontal sand mill, the grinding chamber temperature is controlled at 28℃ to avoid degradation of propylene glycol due to high temperature.

[0073] S3. Add the oligosaccharide combination to the propylene glycol solution, maintain the reactor temperature at 25℃, and use a gradient stirring process: first stir at 200 r / min for 5 min, then gradually increase the speed to 400 r / min at 50 r / min (the rate increase process lasts for 15 min), and then maintain stirring at 400 r / min for 50 min. Detect the absorbance using a UV spectrophotometer (detection wavelength 205 nm) until the absorbance stabilizes (fluctuation range ≤ ±0.02) and there are no suspended particles. The particles (D90 < 5 μm as determined by particle size analyzer) were used to obtain a compound stock solution. The oligosaccharide combination consisted of carboxymethyl chitosan oligosaccharide and amino oligosaccharide in a mass ratio of 1:1.6. The degree of substitution of carboxymethyl chitosan oligosaccharide was 0.8-1.2, the molecular weight was 1000-3000 Da, and the purity was ≥95%. The degree of substitution of amino oligosaccharide was 0.6-1.0, the molecular weight was 1500-3000 Da, and the purity was ≥95%. The mass ratio of propylene glycol ester solution to oligosaccharide combination was 96:7.

[0074] S4. To the compound stock solution, add lentinan, surfactant, composite stabilizer, antifreeze, defoamer, and stress-resistant agent in sequence. After adding each agent, maintain a stirring speed of 300 r / min and stir for 14 min to ensure uniform mixing and obtain a homogeneous mixture. Before use, dissolve the lentinan in deionized water (mass ratio 1:5) to form a lentinan aqueous solution, then add it to the compound stock solution to ensure uniform dispersion. The mass ratio of the compound stock solution, lentinan, surfactant, composite stabilizer, antifreeze, defoamer, and stress-resistant agent is 96:1. The surfactant is obtained by mixing Tween 80 and sodium dodecylbenzenesulfonate in a mass ratio of 3.8:1. The composite stabilizer is composed of 2,6-di-tert-butyl-p-cresol and vitamin E. The antifreeze is propylene glycol. The defoamer is polydimethylsiloxane. The stress-resistant agent is composed of polyethylene glycol 6000 and hydroxypropyl methylcellulose. The mass ratio of 2,6-di-tert-butyl-p-cresol and vitamin E in the composite stabilizer is 1:1. The mass ratio of polyethylene glycol 6000 and hydroxypropyl methylcellulose in the stress-resistant agent is 3:1.

[0075] S5. Adjust the pH of the homogeneous mixture to 6.0 using a 10% citric acid aqueous solution. During the adjustment process, use a precision pH meter (accuracy ±0.01) to monitor in real time and maintain a stirring speed of 200 r / min to avoid excessively high local acid and alkali concentrations. After adjustment, continue stirring for 12 min. After adjustment, allow the mixture to stand at 25℃ for 30 min to settle, and then perform secondary filtration. First, filter through a 0.45 μm polyvinylidene fluoride (PVDF) membrane, and then filter through a 0.1 μm PVDF membrane to remove small impurities (such as undissolved additive particles) to obtain the reconstituted solution. The filter membrane used for secondary filtration should be soaked in deionized water for 10 min before use to avoid introducing impurities into the formulation. The 10% citric acid aqueous solution is obtained by mixing citric acid and deionized water at a mass ratio of 1:9.

[0076] S6. Add deionized water (conductivity ≤10μS / cm) to the reconstituted solution to bring the total mass of the final formulation to 100kg. Maintain a stirring speed of 200r / min and stir for 80min to ensure the system is thoroughly mixed. Then filter the solution using a 0.1μm polyvinylidene fluoride (PVDF) filter membrane (pore size uniformity RSD <5%) to remove minute impurities (such as undissolved adjuvant particles) and obtain a clear and transparent soluble formulation of propylene glycol and oligosaccharide compound.

[0077] Example 4: A method for preparing a soluble concentrate composed of propanetriol and oligosaccharides, comprising the following steps:

[0078] S1. Ethanol, propylene glycol, and diethylene glycol monomethyl ether are mixed in a mass ratio of 3:2:1 to obtain the main solvent. N-methylpyrrolidone is used as a co-solvent. The main solvent and co-solvent are added to a reactor equipped with an anchor-type stirring device (stirring paddle material is 304 stainless steel). The temperature inside the reactor is controlled at 30℃, the stirring speed is 400r / min, and the stirring is carried out for 25min until the system is clear and transparent (transmittance ≥98%), to obtain a mixed solvent. The mass ratio of the main solvent to the co-solvent is 30:15, the purity of ethanol is ≥95%, the purity of propylene glycol is ≥99%, the purity of diethylene glycol monomethyl ether is ≥99%, and the purity of N-methylpyrrolidone is ≥99%.

[0079] S2. Slowly add propylene glycol technical grade (purity ≥98%, melting point 182-184℃, boiling point 350℃±5℃) to the mixed solvent at a mass ratio of 5:99.9 (propylene glycol: mixed solvent). Maintain the reactor temperature at 25℃ and the stirring speed at 300 r / min. Simultaneously, turn on a 400W ultrasonic device (ultrasonic frequency 20kHz) for 15 min to break up the aggregated state of the technical grade. Continue stirring for 40 min, then perform nano-grinding for 25 min using a horizontal sand mill (zirconium bead particle size 0.1-0.3mm) to control the propylene glycol particle size D90≤1μm. After grinding, use high performance liquid chromatography (HPLC) to analyze the results. HPLC detection was performed (column: C18 column 250mm×4.6mm, 5μm; mobile phase: methanol-water = 80:20, v / v; flow rate 1.0mL / min; detection wavelength 230nm; column temperature 30℃) until the peak area stabilized (RSD < 1%) and no impurity peaks were observed, confirming complete dissolution of propylene glycol ester and obtaining a propylene glycol ester solution. In this process, after adding propylene glycol ester technical grade to the mixed solvent, the mixture was first sonicated and then stirred until the propylene glycol ester technical grade was completely dissolved, yielding the propylene glycol ester solution. During horizontal milling, the grinding chamber temperature was controlled at 30℃ to avoid degradation of propylene glycol ester due to high temperature.

[0080] S3. Add the oligosaccharide combination to the propylene glycol solution, maintain the reactor temperature at 25℃, and use a gradient stirring process: first stir at 200 r / min for 5 min, then gradually increase the speed to 400 r / min at 50 r / min (the rate increase process lasts for 15 min), and then maintain stirring at 400 r / min for 60 min. Detect the absorbance using a UV spectrophotometer (detection wavelength 205 nm) until the absorbance stabilizes (fluctuation range ≤ ±0.02) and there are no suspended particles. (D90 < 5 μm as determined by particle size analyzer) to obtain the compound stock solution, wherein the oligosaccharide combination is composed of carboxymethyl chitosan oligosaccharide and amino oligosaccharide in a mass ratio of 1:2. The degree of substitution of carboxymethyl chitosan oligosaccharide is 0.8-1.2, the molecular weight is 1000-3000 Da, and the purity is ≥95%; the degree of substitution of amino oligosaccharide is 0.6-1.0, the molecular weight is 1500-3000 Da, and the purity is ≥95%. The mass ratio of propylene glycol ester solution to oligosaccharide combination is 98.9:10.

[0081] S4. To the compound stock solution, add lentinan, surfactant, composite stabilizer, antifreeze, defoamer, and stress-resistant agent sequentially. After adding each agent, maintain a stirring speed of 300 r / min and stir for 15 min to ensure uniform mixing and obtain a homogeneous mixture. Before use, dissolve the lentinan in deionized water (mass ratio 1:5) to prepare a lentinan aqueous solution, then add it to the compound stock solution, ensuring uniform dispersion. The mass ratio of the compound stock solution, lentinan, surfactant, composite stabilizer, antifreeze, defoamer, and stress-resistant agent is 97:1. The surfactant is obtained by mixing Tween 80 and sodium dodecylbenzenesulfonate in a mass ratio of 4:1. The composite stabilizer is composed of 2,6-di-tert-butyl-p-cresol and vitamin E. The antifreeze agent is propylene glycol. The defoamer is polydimethylsiloxane. The stress-resistant agent is composed of polyethylene glycol 6000 and hydroxypropyl methylcellulose. The mass ratio of 2,6-di-tert-butyl-p-cresol and vitamin E in the composite stabilizer is 1:1. The mass ratio of polyethylene glycol 6000 and hydroxypropyl methylcellulose in the stress-resistant agent is 3:1.

[0082] S5. Adjust the pH of the homogeneous mixture to 7.0 using a 10% sodium hydroxide aqueous solution. During the adjustment process, use a precision pH meter (accuracy ±0.01) to monitor in real time and maintain a stirring speed of 200 r / min to avoid excessively high local acid and alkali concentrations. After adjustment, continue stirring for 15 min. After adjustment, let it stand at 25℃ for 30 min to precipitate, and then perform secondary filtration. First, filter through a 0.45 μm polyvinylidene fluoride (PVDF) filter membrane, and then filter through a 0.1 μm PVDF filter membrane to remove small impurities (such as undissolved additive particles) to obtain the reconstituted solution. The filter membrane of the secondary filtration should be soaked in deionized water for 10 min before use to avoid impurities in the filter membrane being introduced into the formulation. The 10% sodium hydroxide aqueous solution is obtained by mixing sodium hydroxide and deionized water at a mass ratio of 1:9.

[0083] S6. Add deionized water (conductivity ≤10μS / cm) to the reconstituted solution to bring the total mass of the final formulation to 100kg. Maintain a stirring speed of 200r / min and stir for 90min to ensure the system is thoroughly mixed. Then filter the solution using a 0.1μm polyvinylidene fluoride (PVDF) filter membrane (pore size uniformity RSD <5%) to remove minute impurities (such as undissolved adjuvant particles) and obtain a clear and transparent soluble formulation of propylene glycol and oligosaccharide compound.

[0084] Comparative Example 1:

[0085] Compared with Example 1, this comparative example did not undergo nano-grinding, but only ultrasonic non-grinding treatment. All other steps and parameters were the same, and will not be repeated here. The final product was a soluble concentrate of propylene glycol and oligosaccharide.

[0086] Comparative Example 2:

[0087] Compared with Example 1, in step S3 of this comparative example, only the "oligosaccharide combination" is replaced with "single unmodified chitosan oligosaccharide". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a soluble concentrate of propylene glycol and oligosaccharide is obtained.

[0088] Comparative Example 3:

[0089] This comparative example does not contain lentinan, but all other steps and parameters are the same as in Example 1. The final product is a soluble concentrate of propyltrimonium ester and oligosaccharide.

[0090] Comparative Example 4:

[0091] Compared with Example 1, this comparative example did not perform secondary filtration, but replaced secondary filtration with single filtration. All other steps and parameters were the same, and will not be repeated here. The final product was a soluble concentrate of propylene glycol and oligosaccharide.

[0092] Comparative Example 5:

[0093] This comparative example differs from Example 1 only in that the "mixed solvent" is replaced with "single ethanol". All other steps and parameters are the same, and will not be repeated here. The final product is a soluble solution of propanetriol and oligosaccharide.

[0094] Performance testing:

[0095] Formulation stability:

[0096] 1. Low temperature stability: Refer to GB / T19137-2003 Determination of Low Temperature Stability of Pesticides: Store the sample in a refrigerator at -20℃±2℃ for 7 days, observe the layering / crystallization, and use a transmittance meter to measure the transmittance. ≥95% is considered qualified.

[0097] 2. Thermal storage stability: Refer to GB / T19136-2003 "Test Method for Thermal Storage Stability of Pesticides": Store in a constant temperature chamber at 54℃±2℃ for 14 days, use high performance liquid chromatography (HPLC) to determine the residual rate of propanetriol, use ultraviolet spectrophotometer to determine the residual rate of oligosaccharides, and calculate the degradation rate. ≤1.5% is considered qualified.

[0098] 3. Particle size distribution: The particle size of propylene glycol D90 / ≤5μm is qualified as determined by a laser particle size analyzer (Malvin Mastersizer 3000);

[0099] Cold-region rice stress resistance:

[0100] 1. Low-temperature germination rate: The cold-region rice variety "Fuhe 48" was selected. The seeds were diluted 500 times and soaked for 12 hours. After being treated at -5℃ for 24 hours, they were germinated at a constant temperature of 25℃. The germination rate was calculated after 7 days (number of germinated seeds / total number of seeds × 100%).

[0101] 2. Stalk bending strength: At the rice maturity stage, the bending strength of the second internode from the bottom was measured using a digital tensile tester (range 0-50N) / unit: N;

[0102] 3. Lodging area: From the booting stage to maturity, the percentage of lodging area to the experimental area is visually recorded as ≤20% to be considered acceptable;

[0103] Control of powdery mildew in rice:

[0104] Disease index and control effect: Referring to "GB / T17980.134-2004 Guidelines for Field Efficacy Testing of Pesticides (II) Fungicides for the Control of Powdery Mildew in Rice": a water control was set up, and conventional spraying was performed (application rate 179.9 mL·hm²). -2 Record the disease index before and 7 days after application of the pesticide, and calculate the control effect. Disease index = Σ(number of diseased leaves × corresponding disease level value) / (total number of leaves × highest disease level value) × 100 (Disease level: 0 no disease, 1 ≤ 5%, 3 6%-15%, 5 16%-25%, 7 26%-50%, 9 > 50%); Control effect = (disease index of control area - disease index of treatment area) / disease index of control area × 100%;

[0105] Rice yield: Yield per hectare: At rice maturity, three 20 m² plots were selected for each treatment. After harvesting, the rice was threshed and dried (moisture content 14%), weighed, and the yield per hectare was calculated / kg·hm. -2 .

[0106] The test data is shown in Table 1-15 below:

[0107] Table 1. Results of formulation stability tests (Examples 1-2)

[0108]

[0109] Table 2. Results of formulation stability tests (Examples 3-4)

[0110]

[0111] Table 3. Results of formulation stability tests (Comparative Examples 1-2)

[0112]

[0113] Table 4. Results of formulation stability tests (Comparative Examples 3-4)

[0114]

[0115] Table 5. Results of formulation stability tests (Comparative Example 5)

[0116]

[0117] Table 6 Results of stress resistance tests on cold-region rice (Examples 1-2)

[0118]

[0119] Table 7 Results of stress resistance tests on cold-region rice (Examples 3-4)

[0120]

[0121] Table 8 Results of stress resistance tests on cold-region rice (Comparative Examples 1-2)

[0122]

[0123] Table 9 Results of stress resistance tests on cold-region rice (Comparative Examples 3-4)

[0124]

[0125] Table 10 Results of stress resistance tests on cold-region rice (Comparative Example 5)

[0126]

[0127] Table 11 Results of rice powdery mildew control and yield testing (Examples 1-2)

[0128]

[0129] Table 12 Results of rice powdery mildew control and yield test (Examples 3-4)

[0130]

[0131] Table 13 Results of rice powdery mildew control and yield testing (Comparative Examples 1-2)

[0132]

[0133] Table 14 Results of rice powdery mildew control and yield test (Comparative Examples 3-4)

[0134]

[0135] Table 15 Results of rice powdery mildew control and yield test (Comparative Example 5 and water control)

[0136]

[0137] Data Analysis:

[0138] 1. Formulation stability:

[0139] (1) Low temperature stability: In Examples 1-4, there was no layering / crystallization, and the transmittance was 97.8%-98.5%. The core reason is the low temperature solubility of the mixed solvent "ethanol-propylene glycol-diethylene glycol monomethyl ether (3:2:1)" (solubility of 35g / L at -20℃). Combined with the combination of "carboxymethylated chitosan oligosaccharide + amino oligosaccharide" (water solubility of 45g / L), the compatibility contradiction between propylene glycol ester (lipid-soluble) and oligosaccharide (water-soluble) was resolved. In contrast, in Comparative Example 2 (single unmodified chitosan oligosaccharide): the water solubility of unmodified chitosan oligosaccharide was only 30g / L. The solubility dropped sharply at low temperature, and it separated from propylene glycol ester, resulting in 8% crystallization and a transmittance of only 78.5%. This proves the low temperature compatibility advantage of the "oligosaccharide combination". In Comparative Example 5 (single ethanol): the solubility of single ethanol at -20℃ was only 25g / L, which could not dissolve the effective ingredients, resulting in layering and a transmittance of 72.1%. This verifies that the "mixed solvent system" is the basis for antifreeze stability.

[0140] (2) Thermal storage stability: In the example, the degradation rate of propane ester was 1.2%-1.5% and the degradation rate of oligosaccharides was 0.9%-1.2% (both ≤1.5%), which relied on the composite stabilizer "2,6-di-tert-butyl-p-cresol + vitamin E (1:1)": BHT inhibited oxidation, vitamin E chelated metal ions and inhibited the Maillard reaction of oligosaccharides, and the mixed solvent reduced the contact between the active ingredients and air / moisture, further reducing degradation. In contrast, in Comparative Example 2 (single oligosaccharide): the unmodified oligosaccharide had poor compatibility with propane ester, and the interfacial reaction intensified during thermal storage. Moreover, the glycosidic bonds of the unmodified oligosaccharide were easily broken, resulting in a 9.2% degradation of propane ester and a 10.1% degradation of oligosaccharides. In Comparative Example 5 (single ethanol): single ethanol was easily volatilized at 54°C, which caused fluctuations in the system concentration and accelerated the degradation of the active ingredients (13.5% of propane ester and 11.8% of oligosaccharides), highlighting the necessity of the mixed solvent again.

[0141] (3) Particle size distribution: In Examples 1-4, the particle size D90 was controlled at 1.0-1.2μm by "ultrasound (300-400W) + nano-grinding (15-25min)", resulting in a large specific surface area, which laid the foundation for subsequent crop absorption. In Comparative Example 1, the grinding was omitted, the particle size increased to 3.8μm, the specific surface area decreased, and the control efficacy against rice powdery mildew decreased from 74.4% to 68.7%, verifying the irreplaceable role of "ultrasound-nano-grinding coupling process" in particle size control.

[0142] 2. Stress resistance of rice in cold regions:

[0143] (1) Low temperature germination rate: The example met the standard: 84.1%-85.2%. The core is that propylene glycol and diethylene glycol monomethyl ether in the mixed solvent lower the freezing point of the cells, and the stress-resistant adjuvant (PEG-6000+HPMC) enhances the cell membrane's antifreeze properties. The two work together to reduce the damage of low temperature to the seed embryo. In contrast, Comparative Example 5 (single ethanol): there are no antifreeze components, a large number of seed cells freeze and rupture, and the germination rate is only 56.2% (the lowest); Comparative Example 2 (single oligosaccharide): the unmodified oligosaccharide cannot activate the antifreeze gene, and the germination rate is 75.1% (10 percentage points lower than the example).

[0144] (2) Stalk bending strength and lodging area: Example support: bending strength 34.8-35.6N, lodging area 14.8%-15.5%, depending on "oligosaccharide combination + stress resistance adjuvant": amino oligosaccharides promote cellulose synthesis in the stalk, carboxymethylated chitosan oligosaccharides activate stress resistance signals, and HPMC enhances stalk toughness, which together improves lodging resistance. In contrast, Comparative Example 5 (single ethanol): the unstable solvent leads to uneven absorption of effective ingredients and unbalanced stalk development, with a bending strength of 27.8N (lowest) and a lodging area of ​​32.6% (12.6 percentage points above the qualified standard); Comparative Example 2 (single oligosaccharide): the unmodified oligosaccharide cannot effectively promote cellulose synthesis, with a bending strength of 31.8N and a lodging area of ​​25.3% (5.3 percentage points above the qualified standard).

[0145] 3. Efficacy and yield: (1) Control of rice powdery mildew: The control effect of the example was 72.2%-74.4%, which is the synergistic result of "small particle size (good absorption) + oligosaccharide combination (activates immunity) + compound stabilizer (long-lasting effect)": the particle size of 1.0-1.2μm increases the leaf surface contact area, the oligosaccharide combination induces the synthesis of phytoalexin / PR protein, and the compound stabilizer ensures that the efficacy does not decrease 7 days after application. However, Comparative Example 1 (no grinding): the particle size of 3.8μm leads to a decrease in absorption efficiency, and the control effect is 68.7% (a decrease of 5.7%); Comparative Example 3 (without lentinan): although lentinan has a core antiviral effect, the overall immune activation efficiency decreases after its absence, and the control effect is 69.5% (a decrease of 4.9%); Comparative Example 5 (single ethanol): the degradation rate of the active ingredient is high, the actual effective dose is insufficient, and the control effect is 62.3% (a decrease of 12.1%).

[0146] (2) Rice yield: The yield per hectare in the example was 8875-8952 kg, which was 12.9%-13.9% higher than the control (7860 kg). The core of this was the closed loop of "stability to ensure efficacy → stress resistance to reduce losses → efficacy to increase dry matter accumulation": mixed solvent + secondary filtration ensured that the efficacy of the formulation did not decrease during storage; oligosaccharide combination + stress resistance adjuvant reduced yield losses caused by low temperature and lodging; ultrasonic-grinding improved the absorption of active ingredients and increased the number of grains per panicle and the seed setting rate. In contrast, Comparative Example 5 (single ethanol): stability, stress resistance and efficacy decreased, and the yield was 7650 kg (14.5% lower than Example 1); Comparative Example 2 (single oligosaccharide): stability and stress resistance were insufficient, and dry matter accumulation decreased, resulting in a yield of 8210 kg (8.3% lower); Comparative Example 4 (no secondary filtration): the effect on yield was small in the short-term test (8890 kg, the same as Example 4), but the efficacy would decrease due to the decrease in stability during long-term storage.

[0147] This invention innovatively employs a low-temperature mixed solvent system of "ethanol-propylene glycol-diethylene glycol monomethyl ether (3:2:1)" combined with a combination of "carboxymethylated chitosan oligosaccharide + amino oligosaccharide" to effectively solve the problem of solubility difference between propylene glycol ester (lipid-soluble) and oligosaccharide (water-soluble): after 7 days of storage at -20℃, there is no stratification or crystallization, and the light transmittance remains at 97.8%-98.5%; after 14 days of heat storage at 54℃, the degradation rate of propylene glycol ester is only 1.2%-1.5%, and the degradation rate of oligosaccharide is 0.9%-1.2%, far below the industry standard (≤1.5%). Simultaneously, a process of "30 minutes of standing + secondary filtration (0.45μm→0.1μm PVDF filter membrane)" removes tiny adjuvant particles, avoiding accelerated degradation caused by impurities after heat storage, extending the shelf life of the formulation to more than 24 months. This meets the needs of pesticide production, long-distance transportation, and long-term storage in cold fields, reducing efficacy loss and resource waste.

[0148] This invention constructs a ternary compound system of "propanetriol + oligosaccharide combination + lentinan" through scientific formulation, combined with stress-resistant adjuvants (polyethylene glycol 6000 + hydroxypropyl methylcellulose), forming a four-functional closed loop of "growth promotion + disease resistance + cold resistance + lodging resistance".

[0149] Stress resistance: For cold-region rice, the germination rate at low temperatures increased to 84.1%-85.2% (5.5-6.8 percentage points higher than the control in clear water), the stem bending strength reached 34.8-35.6N, and the lodging area was controlled at 14.8%-15.5% (≤20% of the qualified standard), effectively solving the problems of low temperature stress in cold regions and lodging during rice maturity.

[0150] Disease resistance: The control effect against rice powdery mildew reaches 72.2%-74.4%, and the introduction of lentinan expands the disease resistance spectrum, which can simultaneously control viral diseases such as tobacco mosaic virus, making up for the limitation of existing compound preparations that are only antifungal.

[0151] Yield increase: The yield of cold-region rice reached 8875-8952 kg per hectare, which is 12.9%-13.9% higher than the control in clear water (7860 kg), achieving a regulatory value of "1+1>2", which is superior to single propanetriol or oligosaccharide preparations.

[0152] This invention employs a coupled process of "300-400W ultrasonic grinding (10-15 min) + horizontal sand mill nano-grinding (15-25 min)" to precisely control the particle size of propylene glycol to D90≤1μm. Combined with a surfactant system of "Tween 80 + sodium dodecylbenzenesulfonate (3:1-4:1)," it significantly improves the foliar absorption efficiency of crops: the absorption rate of the active ingredient in tobacco leaves is increased by 25% compared to the unground group, and due to the uniform particle size dispersion, the incidence of phytotoxicity decreases from 0.5% to 0. Simultaneously, the selected raw materials are all low-toxicity and easily degradable: the purity of propylene glycol technical grade is ≥98%, the oligosaccharide combination is derived from natural shrimp and crab shell resources, and the solvents and adjuvants (such as propylene glycol and polydimethylsiloxane) all meet green pesticide standards. The oral LD50 in rats is >5000mg / kg, and the dermal LD50 is >2000mg / kg, ensuring crop quality and safety (e.g., increasing the reducing sugar content of grapes to 22%) while avoiding soil and water residues, thus meeting the needs of ecological agriculture development.

[0153] The preparation process of this invention (mixed solvent preparation → ultrasonic-grinding → gradient stirring → secondary filtration → volume adjustment) is fully compatible with existing pesticide soluble formulation production lines, requiring no additional specialized equipment and reducing equipment modification and investment costs for enterprises. Although the cost of carboxymethylated chitosan oligosaccharide is slightly higher than that of unmodified chitosan oligosaccharide, the formulation can reduce the number of pesticide applications during the crop growth period (from the conventional 3-4 times to 2 times), comprehensively reducing farmers' pesticide procurement and manual application costs. Furthermore, the formulation is suitable for various cash crops such as cold-region rice, tobacco, and grapes, with a wide range of applications, suitable for both large-scale planting bases and small-scale farmers, possessing significant practical production value and market potential.

[0154] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

[0155] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for preparing a soluble concentrate of propiconazole and oligosaccharin, characterized by, The method comprises the following steps: Step S1. Add the main solvent and the auxiliary solvent into a reaction kettle, control the temperature in the reaction kettle at 20-30°C, the stirring speed at 200-400 r / min, and stir for 15-25 min until the system is clear and transparent to obtain a mixed solvent; Step S2. Slowly add the propiconazol technical material into the mixed solvent of step S1, keep the temperature of the reaction kettle at 25°C and the stirring speed at 300 r / min, and at the same time, start the 300-400 W ultrasonic equipment to process for 10-15 min, continue to stir for 20-40 min, and then use a horizontal sand mill to perform nanometer grinding for 15-25 min, control the particle size D90 of the propiconazol to be less than or equal to 1 μm, and after grinding, confirm that the propiconazol is completely dissolved to obtain a propiconazol solution; Step S3. Add the oligosaccharin combination into the propiconazol solution, keep the temperature of the reaction kettle at 25°C, and use a gradient stirring process: first stir at 200 r / min for 5 min, then gradually increase the stirring speed to 400 r / min at a rate of 50 r / min, and then keep the stirring speed at 400 r / min for 30-60 min to obtain a compounded stock solution; Step S4. Add lentinan, a surfactant, a composite stabilizer, an antifreezing agent, an antifoaming agent and an anti-reverse aid into the compounded stock solution in sequence, keep the stirring speed at 300 r / min and stir for 10-15 min after adding each auxiliary agent to ensure uniform mixing to obtain a uniform mixture; Step S5. Use a pH regulator to adjust the pH value of the uniform mixture to 5.0-7.0, keep the stirring speed at 200 r / min, continue to stir for 8-15 min after the adjustment is completed, and then stand for 30 min at 25°C, and then perform secondary filtration: first pass through a 0.45 μm polyvinylidene fluoride filter membrane, and then pass through a 0.1 μm PVDF filter membrane to obtain a re-compounded solution; Step S6. Add deionized water into the re-compounded solution to make up to a total mass of 100 kg of the final preparation, keep the stirring speed at 200 r / min, stir for 60-90 min to fully mix the system, and then filter through a 0.1 μm polyvinylidene fluoride filter membrane to remove small impurities to obtain a clear and transparent propiconazol and oligosaccharin compounded soluble solution; The mass ratio of the main solvent to the auxiliary solvent in step S1 is 10-30:5-15, and the main solvent is composed of ethanol, propylene glycol and diethylene glycol monomethyl ether; The mass ratio of ethanol, propylene glycol and diethylene glycol monomethyl ether in the main solvent is 3:2:1; The auxiliary solvent is N-methyl pyrrolidone; The composite stabilizer is composed of 2,6-di-tert-butyl-p-cresol and vitamin E, and the mass ratio of 2,6-di-tert-butyl-p-cresol to vitamin E in the composite stabilizer is 1:1; The anti-reverse aid is composed of polyethylene glycol 6000 and hydroxypropyl methyl cellulose; The mass ratio of the mixed solvent to the propiconazol technical material in step S2 is 95-99.9:0.1-5; The oligosaccharin combination in step S3 is composed of carboxymethyl chitosan and amino oligosaccharin at a mass ratio of 1:1-2, and the mass ratio of the propiconazol solution to the oligosaccharin combination is 90-98.9:1.1-10. The mass ratio of the surfactant to the compound stock solution in step S4 is 3-8:92-97; The mass ratio of the compound stock solution, lentinan, surfactant, composite stabilizer, antifreeze agent, defoaming agent and anti-reverse aid in step S4 is 92-97:0.5-2:3-8:0.2-0.4:7-10:0.08-0.15:2.0-2.

8.

2. The method of preparing a complex soluble solution of propiconazole and oligosaccharin according to claim 1, characterized in that, The purity of the ethanol is ≥95%, the purity of the propylene glycol is ≥99%, the purity of the diethylene glycol monomethyl ether is ≥99%, and the purity of the N-methyl pyrrolidone is ≥99%.

3. The method of preparing propiconazole and oligosaccharin complex soluble concentrate according to claim 1, characterized in that, The purity of the propylene glycol is ≥98%; The temperature of the grinding cavity is controlled at 25-30℃ when the horizontal sand mill is used for grinding in step S2.

4. The method of preparing a complex soluble solution of propiconazole and oligosaccharin according to claim 1, characterized in that, The degree of substitution of the carboxymethyl chitooligosaccharide is 0.8-1.2, the molecular weight is 1000-3000 Da, and the purity is ≥95%; The degree of substitution of the amino chitooligosaccharide is 0.6-1.0, the molecular weight is 1500-3000 Da, and the purity is ≥95%.

5. The method of preparing a complex soluble solution of propiconazole and oligosaccharin according to claim 1, characterized in that, The lentinan in step S4 is dissolved into a lentinan aqueous solution with deionized water before use, and then the compound stock solution is added.

6. The method of preparing a complex soluble solution of propiconazole and oligosaccharin according to claim 1, characterized in that, The surfactant in step S4 is composed of Tween 80 and sodium dodecyl benzene sulfonate; The antifreeze agent is propylene glycol; The defoaming agent is polydimethylsiloxane.

7. The method of preparing a complex soluble solution of propiconazole and oligosaccharin according to claim 1, characterized in that, The mass ratio of Tween 80 to sodium dodecyl benzene sulfonate in the surfactant is 3:1-4:1; The mass ratio of polyethylene glycol 6000 to hydroxypropyl methyl cellulose in the anti-reverse aid is 3:

1.

8. The method of preparing a complex soluble solution of propiconazole and oligosaccharin according to claim 1, characterized by, The filter membrane used for the secondary filtration in step S5 needs to be soaked in deionized water for 10 min before use; The pH regulator in step S5 is a 10% citric acid aqueous solution or a 10% sodium hydroxide aqueous solution; The 10% citric acid aqueous solution is obtained by mixing citric acid and deionized water at a mass ratio of 1:9; and the 10% sodium hydroxide aqueous solution is obtained by mixing sodium hydroxide and deionized water at a mass ratio of 1:9.

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