Existence and preparation of pesticide microemulsification water suspension agent

Antiprecipitation agent generally refers to suspension agent, also known as concentrated suspension agent, flow agent, water suspension, colloidal suspension. A solid pesticide and auxiliary agent that are insoluble in water are ground and dispersed in the water medium, and the continuous phase is water.

Suspension agent is divided into water suspension agent and oil suspension agent. Aqueous suspension agent is water as solvent. The oil suspension agent is oil as the main solvent and does not contain water. Commonly used oils are vegetable oils, such as corn oil, rapeseed oil and so on. It also uses synthetic oils.

The particle size is fine, the general particle size is 0.1~3μm, the suspension rate is high, the drug effect is better than the wettable powder; No organic solvent, low volatility, low toxicity, safe for humans and animals; Non-flammable and explosive, safe storage and transportation, can be sprayed by aircraft. In order to prevent product decomposition, precipitation, caking, freezing, etc., need to add stabilizer, antifreeze, etc.

The suspension agent is a floating suspension of viscose silk, which is mixed with the pesticide agent, carrier and dispersant, and is made by micro-grinding with wet method. It is a solid drug that is insoluble or slightly soluble in water with the help of some auxiliaries, and is more evenly dispersed in water through ultra-fine grinding, forming a stable liquid solid system with fine particles and high suspension and flow. The suspension agent is usually composed of active ingredients, dispersant, thickener, antiprecipitation agent, defoamer, antifreeze and water. The content of active ingredients is generally 5% to 50%. The average particle size is generally about 3 microns. It is a new dosage form for pesticide processing.

In the application of suspension, the water diluent has two dispersion systems: suspension and emulsion. Most of the diluent particles of the suspension are less than 5μm in diameter, and the rest are above 5μm. Both decentralized systems are also unstable. Generally, it only meets the requirements of suspension standard determination. Then under the action of gravity, it does not take much time to gradually precipitate. Can this unstable suspension emulsion be turned into a stable nanoscale transparent or translucent microemulsion?

The existence of pesticide microemulsification water suspension agent

The so-called pesticide microemulsification water suspension agent, that is, after the solid pesticide that is made of water suspension agent is wet superfine ground, the water suspension agent is formed under the action of the pesticide additives, namely dispersant, emulsifier, thickener, antifreeze, preservative, stabilizer, etc., and water, and the diluent is a special pesticide dosage form of transparent or translucent micro-emulsion liquid.

Preparation of 20% furosemide microemulsified water suspension agent

1. Grinding equipment, grinding equipment selected HWLY-0.75 laboratory blue grinding machine produced by Shanghai Hewei Electromechanical Equipment Co., LTD. 0.5L double stainless steel cylinder with manual lifting parts.

2. The active ingredient content of the original drug is required to be greater than 95%. Do not name which one to produce, but to meet the industry and the relevant national technical standards.

3. The active ingredient content of pesticide additives such as xanthan gum, magnesium and aluminum silicate, ethylene glycol, defoamer, sodium benzoate, etc. should be above 95%, and it does not name which one is produced. Only required to meet the relevant industry and national standards.

4. The dispersion emulsifier used is not specified which one is produced, and the selected surfactant monomers for this preparation are all surfactant monomers. Use local and clean tap water.

5. 20% Furosemide microemulsion water suspension formula (%) Furosemide 20.0 (active ingredient content), Xanthan gum 0.30, ethylene glycol 4.0, magnesium and aluminum silicate 0.7, sodium benzoate 0.30, silicone defoamer 0.4, 500 # 1.0, 601 # 3.0, NP-10 # 2.0, clean tap water 100%. The PH value of this product is 6-7. (The active ingredient of the original drug of dinotefuran in this formula is 98.0%).

6. 400g of 20% dinotefuran microemulsion water suspension agent was produced with 0.5L equipment in process operation. According to the above 20% dinotefuran micro-emulsion water suspension formula 4 times the amount of feed into the sander cylinder, feed in no order. Then stir well with a glass rod and put it into the sanding blue of the sander. Then after the manual lifting equipment is used to make it tight and firm, the sander is started and the speed is 1500-1600 RPM. If the summer temperature is high, the water tap switch can be connected to the cylinder jacket water cooling operation, and the outflow cooling water temperature does not exceed 40℃. The grinding time is 2 hours. The samples were tested for diluent, PH value, density, cold storage and active components.

Comparison of pesticide microemulsification water suspension agent and water suspension agent

Identical point

Are water-based environmental protection dosage forms; Are insoluble in water or very little solubility of the pesticide formulation, the appearance is milky white, delicate flow of unstable dispersion system; Processing process flow, the operation is the same.

Difference point

When pesticide microemulsification water suspension is used, the appearance of diluent is transparent or translucent liquid. The diluent of water suspension is generally milky and opaque emulsion in appearance. This emulsion does not stand the test of time and precipitates quickly or easily. Therefore, the pesticide microemulsification water suspension agent with the same active ingredient has better efficacy than water suspension agent.

Comparison of pesticide microemulsification water suspension agent and microemulsion

Identical point

Are water-based environmental protection dosage forms; All of them are formulated with pesticides that do not dissolve in water or dissolve little; When diluted with water in use, it is a transparent or translucent nano-scale dispersion emulsion.

Difference point

The appearance of pesticide microemulsification water suspension is milky white, delicate, opaque and unstable suspension. Microemulsions, on the other hand, are completely colorless and transparent stable liquids. Pesticide microemulsification water suspension does not add organic solvent as solvent to dissolve the pesticide. Organic solvent must be added to the microemulsion. There is less surfactant in pesticide microemulsification water suspension than in microemulsion. The cost of pesticide microemulsification water suspension agent is lower, more environmentally friendly and safer than that of microemulsion.

Characteristics of preparation of pesticide microemulsification water suspension agent

The characteristics of the preparation of pesticide microemulsification water suspension agent are mainly on the base of water suspension agent (SC). Further microemulsifying it. Microemulsification is a complex physicochemical process. Therefore, all pesticide additives required to be added should enhance dispersion, emulsification, solubilization, solubility and stability.

1. The content of pesticide active ingredients should not be too high.

2. The choice of pesticide is best to have a certain small solubility to water.

3. The selection of surfactants, in addition to the special dispersant for water suspension agent, not only pay attention to dispersibility, but also pay attention to emulsification and solubilization. Therefore, monomer or compound emulsifier, anionic and non-ionic surfactants can be considered for emulsifiers of emulsifiers and micro-emulsions.

4. The other pesticide additives added should be water-soluble or hydrophilic as far as possible.

5. The smaller the particle size of the grinding, the better, 0.1-3μm is necessary.

6. Glycol is better for antifreeze and also plays the role of coemulsifier.

Characteristics and significance of pesticide microemulsification water suspension agent

1. Pesticide microemulsification water suspension agent is a new dosage form of pesticide microemulsification water suspension agent. The dosage form is temporarily MS represented by the first word of each microemulsion ME and water suspension agent SC. MS is beneficial to improve the stability of water suspension diluent.

2. It is beneficial to improve the penetration of pesticide dilution solution on plant leaf surface and the epidermis of pests and diseases. It helps to improve the drug effect.

3. Less medicine than conventional pesticide water suspension, more economical and environmentally friendly.

4. Promote the in-depth study of pesticide water suspension agents, further improve the development of water suspension dosage forms towards more efficient, safe, economic and environmental protection, and create favorable conditions for the negative growth of pesticide use.

Turn from the surfactant net.