Why Gravimetric Dosing Matters in Functional Masterbatch
A functional masterbatch only works if every pellet carries the additive load the recipe says it does. How the additives are dosed into the compounder decides whether that is true.
Functional additives work at low loadings. A UV stabiliser, slip agent or antistatic is usually a small fraction of the final film, so a small error in the masterbatch becomes a visible problem on the customer's line.
Too little additive and the function fails: film degrades early in the field, rolls block, or packaging attracts dust. Too much and the converter pays for chemistry they do not need, and can see haze, bloom or seal problems.
Volumetric feeders meter by screw turns, so their output drifts as bulk density, particle size or hopper level changes. Gravimetric, or loss-in-weight, feeders weigh the material continuously and correct the feed rate in real time.
That is why the Aviura line doses carrier resin and additives through Mettler-Toledo loss-in-weight feeders to ±0.5%, under Siemens recipe control with batch data logging.
What gravimetric dosing gives the converter.
When the additive load is consistent, the let-down that worked in the trial keeps working in production.
Converters do not need to add extra masterbatch to cover batch-to-batch variation, which saves cost.
Recipe storage and batch logs mean every lot can be traced back to its settings and raw materials.
Stored recipes and clean feeding make short runs and small lots practical, not a compromise.
When you assess a masterbatch supplier, ask how additives are dosed, what accuracy the feeders hold, and whether batch data is recorded and available with the COA.
Dosing is not the only factor. Dispersion, degassing and filtration matter too. But without accurate dosing, the rest of the process cannot deliver a consistent product.
Precision you can test starts with what goes into the compounder.
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