Silica Anti-block is a fine inorganic additive used in plastic films to reduce blocking and improve film-to-film separation. It creates a micro-rough surface that prevents smooth contact, especially in PE, PP, and BOPP films. Silica particles are chemically stable and offer long-lasting performance without affecting clarity significantly.
| Property | Typical Value |
|---|---|
| Appearance | White powder |
| Average Particle Size (μm) | 2 – 6 |
| SiO₂ Content | ≥ 98% |
| pH Value (5% solution) | 6.0 – 7.5 |
| Loss on Ignition | ≤ 7% |
| Bulk Density | 250 – 350 g/L |
| Problem | Silica Anti-block Benefit |
|---|---|
| Film layers stick together after winding | Creates physical spacing to prevent adhesion |
| Poor roll release and slitting quality | Improves air release and separation |
| Blocking under heat or pressure | Thermally stable particles resist pressure deformation |
| Migrating organic anti-block agents | Inorganic silica remains on surface without migration |
Q1: Will silica affect optical clarity?
Minimal impact when used in small amounts with fine particle size grades.
Q2: Is it compatible with food contact materials?
Yes, food-grade silica is available and widely used in compliant films.
Q3: What is the typical dosage?
Normally 0.1 – 0.8% depending on film thickness and performance target.
