Home/Solutions/Anti-Block for Plastic Film
Anti-Block for Plastic Film
For film opening and anti-blocking, where the additive must reduce surface contact without clouding the film or migrating.
Anti-Block for Plastic Film covers 2 synthetic amorphous silica grades (CAS 7631-86-9) for film opening and anti-blocking, where the additive must reduce surface contact without clouding the film or migrating. Particle size D50 across the range runs 5.5–6 µm, with BET surface area 118–130 m²/g and oil absorption 158–170 g/100 g. SiO₂ content is 96.2–96.5 %. Grades in this range: VS1351, VS1551. Dosage is set by screening in your own system — set the grade first from the constraint that is hardest to correct later, then find the loading that meets your target.
Where it applies
- Blown and cast polyolefin film
- Film opening and anti-blocking
- Packaging film converting
What the solution is built around
Anti-block works by creating micro-asperities that stop two film surfaces from making full contact. The mechanism is geometric, not chemical, so particle size relative to film thickness is the controlling variable. Too fine and the asperities are buried; too coarse and the film hazes or the particle becomes a defect.
Recommended grade structure
Each project starts with a lead grade and at least one comparison grade. Running both against your own control in the first round answers more than running one grade twice.
| Grade | Role | Particle size D50 | Application note |
|---|---|---|---|
| VS1351 | Lead grade | 5.50 µm | Finer route. Preferred where optical clarity is the binding constraint and film gauge is low. |
| VS1551 | Comparison grade | 6.00 µm | Coarser route. More effective separation per unit added, at some cost in clarity. |
Typical properties
| Grade | D50 | SiO2 | BET | Oil abs. | pH | Bulk density |
|---|---|---|---|---|---|---|
| VS1351 | 5.50 µm | 96.5 % | 130 m²/g | 170 g/100 g | 6.3 | 0.37 g/cm³ |
| VS1551 | 6.00 µm | 96.2 % | 118 m²/g | 158 g/100 g | 6.2 | 0.38 g/cm³ |
Actual batch values may vary within tolerance; a COA is supplied per batch on request. Full data for every grade is on the technical data table.
Selecting and screening for this system
Which grade should lead a first screening round?
VS1351 is the usual starting point. Finer route. Preferred where optical clarity is the binding constraint and film gauge is low. Run VS1551 alongside it in the same round rather than running one grade twice — testing two grades against your own control answers more than two rounds on a single grade.
How do these grades differ?
Particle size runs 5.5–6 µm across the pair. The finer grade scatters less light inside the film and generally preserves more clarity; the coarser grade creates more surface effect per unit added. Structure differs too — BET surface area spans 118–130 m²/g, and the higher figure thickens the formulation more at the same loading.
What dosage should I use?
Dosage for this system is confirmed by screening rather than quoted as a fixed figure — it depends on binder, film thickness, application method and the target you are working to. Screen three loadings bracketing your expected value and interpolate. Set the grade first from the constraint that is hardest to correct later, then find the loading.
How should I compare against my current additive?
Compare at matched effect, not matched loading. Different grades have different efficiency, so running a candidate at the incumbent's loading produces a different result — that tells you about efficiency, which is easily corrected, and nothing about the properties that are not. Match the target first, then compare clarity, surface texture and dispersion behaviour at that loading.
What are the sampling and commercial terms?
Samples are free, 200–500 g, freight prepaid by Vistamatt, shipped in 7–10 working days with a screening plan matched to your system. MOQ is 500 kg per grade for standard grades and 2,000 kg for a custom batch; production lead time is 15–25 days, FOB Xiamen or CIF.
What documentation is available?
A TDS per grade, a generic SDS covering the full range in 16-section GHS format, a TSCA compliance declaration for CAS 7631-86-9, and a COA per batch on request. All are available from the downloads page without registration.
Screen these grades in your own system
Send your binder system, application method, film thickness and the target you are working to. We ship a free 200–500 g sample with a screening plan matched to your system, freight prepaid.