Both IOTA21555 and IOTA556 are cosmetic-grade phenyl silicone oils, sharing common characteristics such as easy emulsification, antioxidant properties, and compatibility with formulations. However, their chemical structures and core properties differ fundamentally, leading to different focuses in their suitability for beauty applications.
The essential difference lies in their molecular structure and basic parameters. IOTA21555 is trimethylpentaphenyltrisiloxane, with an extremely high phenyl content, a refractive index of 1.5775-1.5800, and a viscosity of 175 cst at 25°C. It exhibits a more rigid molecular structure and superior gloss-enhancing effects. IOTA556, on the other hand, is polymethylphenylsiloxane, a polymeric silicone oil with a lower phenyl content, a refractive index of only 1.46, and a viscosity of only 22.5 cst. It has a lighter texture and unique ethanol solubility, making it suitable for alcohol-based formulations.
The differences in application are significant. IOTA21555 is characterized by its high gloss and rich texture, effectively enhancing the radiance and shine of makeup and the glossiness of hair. It is also compatible with high-end transparent formulas such as transparent antiperspirants, improving the stickiness of the formula and leaving the skin feeling rich and non-greasy. IOTA556 has a refreshing and silky texture, focusing on moisturizing, anti-stickiness, and softening. It is suitable for basic skincare products such as lotions, creams, and shaving creams, and can also be used as a hair shine enhancer. Due to its excellent alcohol solubility, it is more suitable for refreshing sprays and water-based formulas containing ethanol, making it a universal basic skincare silicone oil.