Emulsifier OS (Sodium sec-alkyl sulfonate) and emulsifier MS-1 (Octylphenol polyoxyethylene ether maleate) are both high-efficiency nonionic/anionic pesticide emulsifiers. They can be used alone or in combination to achieve synergistic effects. Before use, the type and dosage ratio of emulsifiers should be determined according to the target formulation type (EC, EW, ME, SC, etc.).
General operation procedure: (1) Weigh the emulsifier according to the formulation ratio; (2) Mix the emulsifier with the pesticide technical material and organic solvent (e.g., xylene, solvent oil) and stir until completely dissolved to form a uniform oil phase; (3) Under stirring, slowly add the oil phase to the water phase (or in reverse order) and continue stirring until a uniform and stable emulsion is formed. For EW and ME systems, high-shear emulsifiers or homogenizers are recommended for high-energy emulsification to achieve finer droplet size and better stability.
Blending suggestion: Emulsifier OS has excellent wetting and penetration properties, while MS-1 has outstanding emulsification stability. Blending them in a certain ratio (e.g., OS:MS-1 = 1:1 to 1:3) can balance rapid emulsification and long-term storage stability, especially suitable for complex pesticide combination systems. The specific blending ratio should be determined through HLB value matching experiments and stability tests to find the optimal solution.
| Item | Emulsifier OS | Emulsifier MS-1 |
|---|---|---|
| Chemical Name | Sodium sec-alkyl sulfonate | Octylphenol polyoxyethylene ether maleate |
| Appearance | Light yellow to yellowish brown oily liquid | Brownish red viscous liquid |
| Ion Type | Anionic | Nonionic/Anionic |
| CAS No. | 68439-50-9 | Not available |
| Recommended dosage range (EC) | 5%~12% | 3%~10% |
| Recommended dosage range (EW) | 3%~8% | 4%~10% |
| Applicable pH range | 5~9 | 4~9 |
| Hard water resistance | Excellent | Good |
Pesticide Emulsifiable Concentrate (EC) Processing: Mix OS or MS-1 with the pesticide technical material and organic solvent according to the ratio and stir until a transparent and uniform solution is obtained. OS focuses on improving the wetting and spreading ability of the spray liquid on the target, while MS-1 focuses on the long-term storage stability of the emulsion. For difficult EC systems, it is recommended to use a combination of OS and MS-1.
Emulsion in Water (EW) Preparation: First dissolve the emulsifier in the oil phase, then slowly add the oil phase to the water phase under high-speed shearing. It is recommended to use MS-1 as the main emulsifier (due to its superior overall emulsifying performance) and supplement it with OS to enhance wetting and penetration. The shearing time is usually 5~15 minutes to obtain a uniform emulsion droplet size.
Suspension Concentrate (SC) System: OS can be used as a wetting and dispersing aid, with a recommended dosage of 2%~5%. It is added before grinding to help wet and disperse the solid technical particles in water, preventing sedimentation and caking. MS-1 is usually used as an auxiliary stabilizer in this system, with a dosage of 1%~3%.
Tank-Mix Adjuvant Application: Directly add the emulsifier to the spray tank, mix with water thoroughly, and then add the pesticide formulation. The recommended addition amount of OS is 0.05%~0.2% of the spray volume, which can significantly improve the spreading and adhesion of the spray liquid on leaf surfaces.