A highly stable mancozeb suspension and its preparation method

Abstract

This invention discloses a highly stable mancozeb suspension and its preparation method, solving the technical problems of easy paste formation, easy hydrolysis of active ingredients, and poor storage stability of existing mancozeb suspensions. The suspension consists of the following components by mass percentage: mancozeb technical, polycarboxylate dispersant, polyether dispersant / wetting agent, ethylene glycol or urea, xanthan gum, silicone defoamer, chelating agent, metal salt, preservative Kathon, other adjuvants, and water to 100%. The preparation method is simple and controllable, suitable for industrial production. Stable dispersion of the technical is achieved through the synergistic effect of the electrostatic repulsion of polycarboxylate and the steric hindrance of the polyether adjuvant. Combined with the chelating agent to chelate hard water ions and precise control of the system pH and particle size, the storage stability of the suspension is significantly improved. Even after heat storage, the suspension rate remains above 90%, and the decomposition rate of the active ingredient is low. Simultaneously, the paste formation problem is solved, and it also exhibits good dispersibility, wetting, and flowability.

Description

Technical Field

[0001] This invention belongs to the field of pesticide formulation technology, specifically relating to a highly stable mancozeb suspension and its preparation method. Background Technology

[0002] Mancozeb is a broad-spectrum, highly effective organosulfur fungicide widely used for the control of fungal diseases in fruit trees, vegetables, and grain crops, and has significant application value in agricultural production. Early mancozeb formulations were primarily wettable powders. These formulations generated large amounts of fine dust during production, transportation, and application, posing serious health risks to operators and causing severe environmental pollution. Furthermore, wettable powders have relatively poor dispersibility and suspension properties, resulting in low pesticide utilization efficiency, and packaging residues easily lead to pesticide waste and secondary pollution.

[0003] To address the aforementioned shortcomings of wettable powders, engineers developed mancozeb suspension concentrate. This formulation is dust-free during production and use, produces finer active ingredient particles, and exhibits superior dispersibility and suspension properties. It also demonstrates strong adhesion and uniform coverage on target crops, effectively improving pesticide utilization. However, the preparation and application of mancozeb suspension concentrate still face several technical challenges: First, it is prone to paste formation during milling and long-term storage, leading to loss of flowability and rendering it unusable. Second, mancozeb undergoes slow hydrolysis in water, causing decomposition of the active ingredient and reducing its control efficacy. Third, hard water ions such as calcium and magnesium in the formulation system react with dispersing agents, disrupting the stability of the dispersion system and further exacerbating particle aggregation and sedimentation. Fourth, the chemical properties of mancozeb are significantly affected by pH, with accelerated decomposition under alkaline conditions, necessitating stringent pH control in the formulation.

[0004] To address the aforementioned technical problems, there is an urgent need in this field to develop a highly stable mancozeb suspension that can solve issues such as paste formation, easy hydrolysis of active ingredients, and poor storage stability, in order to meet the actual needs of agricultural production. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a highly stable mancozeb suspension and its preparation method, thereby solving the above-mentioned technical problems existing in the prior art.

[0006] The objective of this invention can be achieved through the following technical solutions: A highly stable mancozeb suspension comprises the following components in weight percentage: 24-34% mancozeb technical grade, 1-10% polycarboxylate dispersant, 2-8% polyether dispersant and wetting agent, 3-8% antifreeze agent, 0.01-1.0% xanthan gum, 0.1-0.8% silicone defoamer, 0.02-2% chelating agent, 1-6% metal salt, 0.1-0.5% Kathon preservative, 0.5-5% other adjuvants, and water to 100%. The antifreeze is either ethylene glycol or urea. The chelating agent is either disodium EDTA or BHT. The water is deionized water.

[0007] Furthermore, the optimal mass percentages of each component are as follows: 30% mancozeb technical grade, 5% polycarboxylate dispersant, 5% polyether dispersant and wetting agent, 4% ethylene glycol, 0.2% xanthan gum, 0.3% silicone defoamer, 0.5% disodium EDTA, 3% metal salt, 0.2% Kathon preservative, 2% other additives, and deionized water to make up to 100%.

[0008] Furthermore, the effective content of the mancozeb technical is 85%.

[0009] Furthermore, the polyether-based dispersing and wetting agent is a block polyether-based additive; The metal salt is a stabilizer; The other adjuvants are conventional functional adjuvants used in pesticide formulations.

[0010] The preparation method of the highly stable mancozeb suspension includes the following steps: S1. Preparation of xanthan gum aqueous solution: Take 70 parts of deionized water, slowly add the weighed xanthan gum under low-speed magnetic stirring, increase the stirring speed until the xanthan gum is completely dissolved, forming a uniform semi-transparent colloidal solution. S2. Preparation of aqueous system: Add polycarboxylate dispersant, polyether dispersant and wetting agent, antifreeze agent, preservative Kathon, chelating agent and metal salt sequentially to xanthan gum aqueous solution in step S1, and stir until all components are completely dissolved to obtain a homogeneous aqueous system. S3. Pre-dispersion and defoaming: Slowly add mancozeb technical powder to the aqueous phase system, and use a high-speed shear dispersion emulsifier to shear at 2000-4000 rpm for 2-3 minutes to obtain a preliminary uniform high-concentration slurry; add organosilicon defoamer, and continue high-speed shearing for 1-2 minutes to eliminate the foam generated by shearing; S4. Sand milling treatment: Add zirconia beads with a diameter of 0.4-1.0 mm to the pre-dispersed slurry. The filling amount of zirconia beads is 60-70% of the slurry bottle volume. Circulate and grind at a speed of 1000-2000 rpm for 0.5-1 h. S5. Post-processing: Pour out the slurry after grinding to meet the standard, rinse the sand mill and zirconia beads with the remaining deionized water, recover the residual slurry and combine it with the ground slurry; stir magnetically at low speed for 15-30 minutes until the system is homogeneous, add deionized water to the total mass of 100 parts, and obtain the highly stable mancozeb suspension.

[0011] Furthermore, the parameters of the sand mill are: frequency range 0.1-400HZ, power 0.75KW, and voltage 380V.

[0012] Furthermore, the pH value of the prepared mancozeb suspension was controlled at 5-8.

[0013] Furthermore, the pH value of the prepared mancozeb suspension is controlled within the weakly acidic to neutral range of 6-7; if the pH value deviates, citric acid is used for adjustment.

[0014] Furthermore, the grinding temperature is controlled at ≤20℃, and the grinding is carried out until the slurry particle D97 is 1-5μm, and D97 < 5μm.

[0015] Furthermore, the viscosity of the suspending agent is 300-2000 mPa·s, and the suspension rate is ≥90% after being stored at 52-56℃ for 14 days.

[0016] The beneficial effects of this invention are: 1. This invention achieves stable dispersion of mancozeb technical particles through the synergistic effect of electrostatic repulsion of polycarboxylate and steric hindrance of polyether adjuvants, fundamentally solving the problems of easy paste formation and particle agglomeration and sedimentation of existing suspensions, and ensuring that the formulation maintains good fluidity during storage.

[0017] 2. The addition of chelating agents such as disodium EDTA or BHT in this invention can efficiently chelate hard water ions in the system, preventing hard water ions from damaging the ionization layer of polycarboxylate. At the same time, the use of deionized water further avoids interference from hard water ions, ensuring the long-term stability of the dispersion system.

[0018] 3. By precisely controlling the pH value of the formulation system within the weakly acidic to neutral range of 6-7, and in conjunction with the use of metal salt stabilizers, this invention significantly slows down the hydrolysis rate of mancozeb, reduces the decomposition rate of the active ingredient, and ensures that the content of the active ingredient remains basically stable after heat storage, thereby improving the duration of efficacy of the drug.

[0019] 4. The suspension particles of the present invention have a D97 of <5μm after sand milling, resulting in fine particle size and narrow distribution, which greatly improves the dispersibility and wettability of the formulation, strengthens its adhesion to the target crop, and provides more uniform coverage, effectively improving the utilization rate of pesticides. At the same time, the droplets of the suspension after being diluted with water and sprayed are larger, and the drift is much lower than that of traditional powders, reducing environmental pollution.

[0020] 5. The preparation process of this invention is simple and controllable, with clear core parameters. The equipment used for processes such as sand milling and shearing is conventional equipment in pesticide formulation production, and no additional special equipment is required, making it suitable for large-scale industrial production. No dust is generated during the preparation process, which is friendly to operators and conforms to the development concept of green chemical industry.

[0021] 6. After 14 days of room temperature storage, 14 days of hot storage, and 7 days of cold storage, the suspending agent of the present invention still maintains good suspension and fluidity, without layering, caking, or paste formation. After 14 days of hot storage at 54±2℃, the suspension rate is still ≥90%, and the stability is significantly better than that of the mancozeb suspending agent in the prior art. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0023] Figure 1 This is a flowchart of the preparation method according to an embodiment of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] In this embodiment of the invention, the effective content of mancozeb technical is 85%, and the percentage conversion is set according to the gradient of 24-34% in claim 1. The actual dosage = percentage conversion ÷ 85%. The polycarboxylate dispersant, block polyether dispersant and wetting agent and other additives are all commercially available industrial products. The deionized water has low conductivity and is free from interference from hard water ions such as calcium and magnesium. The sand mill adopts the parameters of frequency 0.1-400HZ, power 0.75KW, voltage 380V, and the sand milling temperature is ≤20℃ throughout the process. The viscosity of the resulting suspension is controlled at 300-2000mPa・s, the pH is controlled at 5-8 (preferably 6-7, and citric acid is used to adjust if it deviates), and the grinding particle size D97 meets the requirement of 1-5μm and D97 < 5μm.

[0026] Example 1 The formula composition (based on 100g of finished product) includes the following components: Mancozeb technical grade (24% concentration, actual dosage 24 ÷ 85% ≈ 28.24 g), polycarboxylate dispersant 1% (1 g, lower limit of adjuvant), block polyether dispersant and wetting agent 2% (2 g, lower limit of adjuvant), ethylene glycol 3% (3 g, lower limit of adjuvant), xanthan gum 0.01% (0.01 g, lower limit of adjuvant), silicone defoamer 0.1% (0.1 g, lower limit of adjuvant), disodium EDTA 0.02% (0.02 g, lower limit of adjuvant), metal salt 1% (1 g, lower limit of adjuvant), preservative Kathon 0.1% (0.1 g, lower limit of adjuvant), other adjuvants 0.5% (0.5 g, lower limit of adjuvant), deionized water to 100 g.

[0027] Its preparation method includes the following steps: S1. Preparation of xanthan gum aqueous solution: Take 70g of deionized water, slowly add 0.01g of xanthan gum under low-speed magnetic stirring, and speed up until completely dissolved to form a homogeneous semi-transparent colloidal solution; S2. Preparation of aqueous system: Add 1g of polycarboxylate dispersant, 2g of block polyether dispersant and wetting agent, 3g of ethylene glycol, 0.1g of Kathon, 0.02g of disodium EDTA and 1g of metal salt to the S1 solution in sequence, and stir until completely dissolved to obtain a homogeneous aqueous system; S3. Pre-dispersion and defoaming: Slowly add 28.24g of mancozeb technical grade, shear at 2000rpm for 3min using a high-speed shear dispersion emulsifier, add 0.1g of silicone defoamer, and continue shearing at 2000rpm for 2min to defoam; S4. Sand milling treatment: Transfer the slurry to the slurry bottle of the sand mill, add 0.4mm zirconia beads (filling amount 60%, lower limit), and circulate and grind at 1000rpm for 1h (lower limit speed) until D97=4.8μm; S5. Post-processing: Pour out the slurry, rinse the equipment with the remaining deionized water and recover the residual slurry, combine them and stir at low speed for 30 minutes, add deionized water to 100g, adjust the pH to 6.0 with citric acid to obtain the finished product.

[0028] Quality inspection results Before storage: Mancozeb content 24.0%, suspension rate 99.5%, viscosity 550 mPa·s; after 14 days of hot storage at 54±2℃: content 23.9%, suspension rate 99.6%, pH=6.01, no paste formation, stratification, or bottoming out, good fluidity; after 7 days of cold storage at 0±2℃: no freezing, no stratification after thawing, suspension rate 99.0%, good fluidity.

[0029] Example 2 The formula composition (based on 100g of finished product) includes the following components: Mancozeb technical grade (27% concentration, actual dosage 27÷85%≈31.76g), polycarboxylate dispersant 3% (3g), block polyether dispersant and wetting agent 4% (4g), urea 5% (5g, antifreeze replacement), xanthan gum 0.2% (0.2g), silicone defoamer 0.3% (0.3g), BHT 0.5% (0.5g, chelating agent replacement), metal salt 2% (2g), preservative Kathon 0.2% (0.2g), other adjuvants 1% (1g), deionized water to make up to 100g.

[0030] The preparation method includes the following steps: S1. Preparation of xanthan gum aqueous solution: Take 70g of deionized water, add 0.2g of xanthan gum under low-speed magnetic stirring, and speed up until completely dissolved to form a colloidal solution; S2. Preparation of aqueous system: Add 3g of polycarboxylate dispersant, 4g of block polyether dispersant and wetting agent, 5g of urea, 0.2g of Kathon, 0.5g of BHT and 2g of metal salt to the S1 solution in sequence, and stir until completely dissolved to obtain an aqueous system; S3. Pre-dispersion and defoaming: Add 31.76g of mancozeb technical grade, shear at 2500rpm for 2.8min, add 0.3g of defoamer, and continue shearing at 2500rpm for 1.5min to defoam; S4. Sand milling treatment: Add 0.5mm zirconia beads (62% loading), circulate and mill at 1200rpm for 0.8h, and mill until D97=4.0μm; S5. Post-treatment: Rinse the recovered slurry, combine and stir at low speed for 25 minutes, add water to 100g, adjust pH to 6.1, and obtain the finished product.

[0031] Quality inspection results Before storage: Mancozeb content 27.0%, suspension rate 99.6%, viscosity 552 mPa·s; after 14 days of hot storage at 54±2℃: content 26.8%, suspension rate 99.7%, pH=6.11, no paste formation, stratification, or bottoming out, good fluidity; after 7 days of cold storage at 0±2℃: no freezing, no stratification after thawing, suspension rate 99.1%, good fluidity.

[0032] Example 3 The formula composition (based on 100g of finished product) includes the following components: Mancozeb technical grade (30% concentration, actual dosage 30 ÷ 85% ≈ 35.29 g), polycarboxylate dispersant 5% (5 g), block polyether dispersant and wetting agent 5% (5 g), ethylene glycol 4% (4 g), xanthan gum 0.2% (0.2 g), silicone defoamer 0.3% (0.3 g), disodium EDTA 0.5% (0.5 g), metal salt 3% (3 g), preservative Kathon 0.2% (0.2 g), other adjuvants 2% (2 g), deionized water to make up to 100 g.

[0033] The preparation method includes the following steps: S1. Preparation of xanthan gum aqueous solution: Take 70g of deionized water, add 0.2g of xanthan gum under low-speed magnetic stirring, and speed up until completely dissolved to form a colloidal solution; S2. Preparation of aqueous system: Add 5g of polycarboxylate dispersant, 5g of block polyether dispersant and wetting agent, 4g of ethylene glycol, 0.2g of Kathon, 0.5g of disodium EDTA and 3g of metal salt to the S1 solution in sequence, and stir until completely dissolved to obtain aqueous system; S3, Pre-dispersion and defoaming: Add 35.29g of mancozeb technical grade, shear at 3000rpm for 2.5min (medium speed is optimal), add 0.3g of defoamer, and continue shearing at 3000rpm for 1.5min to defoam; S4. Sand milling treatment: Add 0.7mm zirconia beads (65% loading), circulate and mill at 1500rpm for 0.7h, and mill until D97=2.0μm; S5. Post-treatment: Rinse the recovered slurry, combine and stir at low speed for 20 minutes, add water to 100g, adjust pH to 6.5, and obtain the finished product.

[0034] Quality inspection results Before storage: Mancozeb content 30.0%, suspension rate 99.6%, viscosity 535 mPa·s; after 14 days of hot storage at 54±2℃: content 29.8%, suspension rate 99.5%, pH=6.37, no paste formation, stratification, or bottoming, good fluidity; after 7 days of cold storage at 0±2℃: no freezing, no stratification after thawing, suspension rate 99.2%, good fluidity.

[0035] Example 4 The formula composition (based on 100g of finished product) includes the following parts by weight: Mancozeb technical grade (32% concentration, actual dosage 32 ÷ 85% ≈ 37.65g), polycarboxylate dispersant 8% (8g), block polyether dispersant and wetting agent 6% (6g), ethylene glycol 7% (7g), xanthan gum 0.8% (0.8g), silicone defoamer 0.6% (0.6g), BHT 1.5% (1.5g), metal salt 5% (5g), preservative Kathon 0.4% (0.4g), other adjuvants 4% (4g), deionized water to make up to 100g.

[0036] The preparation method includes the following steps: S1. Preparation of xanthan gum aqueous solution: Take 70g of deionized water, add 0.8g of xanthan gum under low-speed magnetic stirring, and speed up until completely dissolved to form a colloidal solution; S2. Preparation of aqueous system: Add 8g of polycarboxylate dispersant, 6g of block polyether dispersant and wetting agent, 7g of ethylene glycol, 0.4g of Kathon, 1.5g of BHT and 5g of metal salt to the S1 solution in sequence, and stir until completely dissolved to obtain an aqueous system; S3. Pre-dispersion and defoaming: Add 37.65g of mancozeb technical grade, shear at 3500rpm for 2.2min, add 0.6g of defoamer, and continue shearing at 3500rpm for 1.2min to defoam; S4. Sand milling treatment: Add 0.8mm zirconia beads (68% loading), circulate and mill at 1800rpm for 0.6h, and mill until D97=3.2μm; S5. Post-treatment: Rinse the recovered slurry, combine and stir at low speed for 18 minutes, add water to 100g, adjust pH to 6.8, and obtain the finished product.

[0037] Quality inspection results Before storage: Mancozeb content 32.0%, suspension rate 99.5%, viscosity 560 mPa·s; after 14 days of hot storage at 54±2℃: content 31.7%, suspension rate 99.4%, pH=6.13, no paste formation, stratification, or bottoming out, good fluidity; after 7 days of cold storage at 0±2℃: no freezing, no stratification after thawing, suspension rate 99.0%, good fluidity.

[0038] Example 5 The formula composition (based on 100g of finished product) includes the following parts by weight: Mancozeb technical grade (34% concentration, actual dosage 34 ÷ 85% = 40g, precise value), polycarboxylate dispersant 10% (10g, maximum allowable additive), block polyether dispersant and wetting agent 8% (8g, maximum allowable additive), urea 8% (8g, maximum allowable additive), xanthan gum 1.0% (1.0g, maximum allowable additive), silicone defoamer 0.8% (0.8g, maximum allowable additive), disodium EDTA 2% (2g, maximum allowable additive), metal salt 6% (6g, maximum allowable additive), preservative Kathon 0.5% (0.5g, maximum allowable additive), other additives 5% (5g, maximum allowable additive), deionized water to bring the total to 100g.

[0039] Preparation method S1. Preparation of xanthan gum aqueous solution: Take 70g of deionized water, add 1.0g of xanthan gum under low-speed magnetic stirring, and speed up until completely dissolved to form a colloidal solution; S2. Preparation of aqueous system: Add 10g of polycarboxylate dispersant, 8g of block polyether dispersant and wetting agent, 8g of urea, 0.5g of Kathon, 2g of disodium EDTA and 6g of metal salt to the S1 solution in sequence, and stir until completely dissolved to obtain aqueous system; S3. Pre-dispersion and defoaming: Add 40g of mancozeb technical grade, shear at 4000rpm for 2min (maximum speed limit), add 0.8g of defoamer, and continue shearing at 4000rpm for 1min to defoam (maximum speed limit). S4. Grinding treatment: Add 1.0mm zirconia beads (70% of the total load, maximum capacity), and grind at 2000rpm for 0.5h (maximum speed / minimum time) until D97=3.5μm; S5. Post-treatment: Rinse the recovered slurry, combine and stir at low speed for 15 minutes (lower limit time), add water to 100g, adjust pH to 7.0, and obtain the finished product.

[0040] Quality inspection results Before storage: Mancozeb content 33.9.0%, suspension rate 99.6%, viscosity 546 mPa·s; after 14 days of hot storage at 54±2℃: content 33.7%, suspension rate 99.6%, pH=6.25, no paste formation, stratification, or bottoming, good fluidity; after 7 days of cold storage at 0±2℃: no freezing, no stratification after thawing, suspension rate 99.1%, good fluidity.

[0041] Comparative Example 1 The formula composition (based on 100g of finished product) includes the following components: Mancozeb technical grade (22% concentration, actual dosage ≈ 25.88g, lower than the 24% lower limit), 5% conventional mineral oil dispersant (5g, no special dispersant / wetting agent for this invention), 4% ethylene glycol (4g), 0.2% xanthan gum (0.2g), 0.3% organosilicon defoamer (0.3g), 3% metal salt (3g), 0.2% Kathon (0.2g), and tap water to make up to 100g (no deionized water / chelating agent).

[0042] Preparation method Using existing conventional processes, the grinding temperature was not controlled (natural room temperature), and the grinding was completed to D97≈6μm (exceeding the range of 1-5μm). The pH was not adjusted (natural pH≈8.6, alkalinity exceeding the range of 5-8). The remaining steps are similar to those of this invention.

[0043] Quality inspection results Before storage: Mancozeb content 22.0%, suspension rate 58%, viscosity 1550 mPa・s; after 14 days of hot storage at 54±2℃: severe paste formation and loss of fluidity; after 7 days of cold storage at 0±2℃: severe freezing and irreversible stratification after thawing.

[0044] Comparative Example 2 The formula composition (based on 100g of finished product) includes the following components: Mancozeb technical grade (36% concentration, actual dosage ≈ 42.35g, higher than the 34% upper limit), polycarboxylate dispersant 5% (5g), block polyether dispersant and wetting agent 5% (5g), ethylene glycol 4% (4g), xanthan gum 0.2% (0.2g), silicone defoamer 0.3% (0.3g), disodium EDTA 0.5% (0.5g), metal salt 3% (3g), Kathon 0.2% (0.2g), other adjuvants 2% (2g), deionized water to make up to 100g.

[0045] The preparation method is exactly the same as that in Example 3 (optimal ratio) of the present invention, with no process adjustment.

[0046] Quality inspection results Before storage: Mancozeb content 36.0%, suspension rate 40%, viscosity 1670 mPa・s; after 14 days of hot storage at 54±2℃: obvious paste formation, with lumps at the bottom; after 7 days of cold storage at 0±2℃: no freezing, the system becomes viscous and pasty.

[0047] The performance of the example and the comparative example is compared in Table 1 below: Table 1

[0048] Technical Conclusion: The five embodiments of this invention fully cover the 24-34% 100% ratio range of mancozeb technical, and the ratio of adjuvants simultaneously covers the major ranges such as 1-10% (polycarboxylate) and 2-8% (block polyether), while achieving the replacement and adaptation of antifreeze (ethylene glycol / urea) and chelating agent (disodium EDTA / BHT). All the suspensions prepared in the examples showed no signs of paste formation, stratification, or freezing under the conditions of heat storage at room temperature and 54±2℃ for 14 days and cold storage at 0±2℃ for 7 days. The suspension rate after heat storage was ≥96.9%, and the decomposition rate of the effective ingredients was extremely low, proving that the formulation range and preparation method of the present invention have wide applicability and stability. Comparative Example 1 (drug content below the lower limit + no core adjuvant) and Comparative Example 2 (drug content above the upper limit) both deviated from the drug content range. Furthermore, Comparative Example 1 suffered from uncontrolled process parameters and the lack of a dedicated adjuvant, resulting in a significant decrease in the stability of the suspension, leading to problems such as paste formation, layering, and freezing. This fully demonstrates that the 24-34% mancozeb content range is one of the core limiting conditions for achieving the high stability of this invention. It works synergistically with adjuvants such as polycarboxylate and block polyether, and none of them can be omitted.

[0049] The high-stability mancozeb suspension concentrate of this invention has a scientifically sound and reasonable formulation, with significant synergistic effects among its components, overcoming the core technical deficiencies of existing mancozeb suspension concentrates. Its preparation method is simple, using conventional equipment found in pesticide formulation production, with clearly defined and controllable process parameters, facilitating large-scale industrial production. The suspension concentrate of this invention exhibits high stability, good dispersibility, safe use, and environmental friendliness, with high pesticide utilization efficiency, possessing broad market application prospects and significant economic and social value.

[0050] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A highly stable mancozeb suspension, characterized in that, It consists of the following components by weight percentage: 24-34% mancozeb technical, 1-10% polycarboxylate dispersant, 2-8% polyether dispersant and wetting agent, 3-8% antifreeze, 0.01-1.0% xanthan gum, 0.1-0.8% silicone defoamer, 0.02-2% chelating agent, 1-6% metal salt, 0.1-0.5% Kathon preservative, 0.5-5% other adjuvants, and water to 100%. The antifreeze is either ethylene glycol or urea. The chelating agent is either disodium EDTA or BHT. The water is deionized water.

2. The highly stable mancozeb suspension according to claim 1, characterized in that, The optimal mass percentages of each component are as follows: 30% mancozeb technical, 5% polycarboxylate dispersant, 5% polyether dispersant and wetting agent, 4% ethylene glycol, 0.2% xanthan gum, 0.3% silicone defoamer, 0.5% disodium EDTA, 3% metal salt, 0.2% Kathon preservative, 2% other additives, and deionized water to make up to 100%.

3. The highly stable mancozeb suspension according to claim 1, characterized in that, The effective content of the mancozeb technical is 85%.

4. The highly stable mancozeb suspension according to claim 1, characterized in that, The polyether dispersant and wetting agent is a block polyether additive; The metal salt is a stabilizer; The other adjuvants are conventional functional adjuvants used in pesticide formulations.

5. A method for preparing a highly stable mancozeb suspension as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Preparation of xanthan gum aqueous solution: Take 70 parts of deionized water, slowly add the weighed xanthan gum under low-speed magnetic stirring, increase the stirring speed until the xanthan gum is completely dissolved, forming a uniform semi-transparent colloidal solution. S2. Preparation of aqueous system: Add polycarboxylate dispersant, polyether dispersant and wetting agent, antifreeze agent, preservative Kathon, chelating agent and metal salt sequentially to xanthan gum aqueous solution in step S1, and stir until all components are completely dissolved to obtain a homogeneous aqueous system. S3. Pre-dispersion and defoaming: Slowly add mancozeb technical powder to the aqueous phase system, and use a high-speed shear dispersion emulsifier to shear at 2000-4000 rpm for 2-3 minutes to obtain a preliminary uniform high-concentration slurry; add organosilicon defoamer, and continue high-speed shearing for 1-2 minutes to eliminate the foam generated by shearing; S4. Sand milling treatment: Add zirconia beads with a diameter of 0.4-1.0 mm to the pre-dispersed slurry. The filling amount of zirconia beads is 60-70% of the slurry bottle volume. Circulate and grind at a speed of 1000-2000 rpm for 0.5-1 h. S5. Post-processing: Pour out the slurry after grinding to meet the standard, rinse the sand mill and zirconia beads with the remaining deionized water, recover the residual slurry and combine it with the ground slurry; stir magnetically at low speed for 15-30 minutes until the system is homogeneous, add deionized water to the total mass of 100 parts, and obtain the highly stable mancozeb suspension.

6. The method for preparing the highly stable mancozeb suspension according to claim 5, characterized in that, The parameters of the mill are: frequency range 0.1-400HZ, power 0.75KW, voltage 380V.

7. The method for preparing the highly stable mancozeb suspension according to claim 5, characterized in that, The pH value of the prepared mancozeb suspension was controlled between 5 and 8.

8. The method for preparing the highly stable mancozeb suspension according to claim 7, characterized in that, The pH value of the prepared mancozeb suspension was controlled within the weakly acidic to neutral range of 6-7; If the pH value deviates from the recommended level, adjust it with citric acid.

9. The method for preparing the highly stable mancozeb suspension according to claim 5, characterized in that, The grinding temperature is controlled at ≤20℃, and the grinding is carried out until the slurry particle D97 is 1-5μm, and D97 < 5μm.

10. The highly stable mancozeb suspension according to any one of claims 1-4, characterized in that, The viscosity of the suspending agent is 300-2000 mPa·s, and the suspension rate is ≥90% after being stored at 52-56℃ for 14 days.

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