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Two compounds with identical formulas can perform differently purely because of the order and temperature at which ingredients went into the mixer. Sequence is a real specification, not a shop-floor preference.

Typical first stage (masterbatch)

• •Polymer first, allow it to break down to a workable viscosity.
• •Add zinc oxide and stearic acid early — they are activators and need to disperse before the filler competes for shear.
• •Add filler in portions together with the oil, keeping the temperature rising steadily so dispersion happens before the batch gets too soft to shear.
• •Add antidegradants and processing aids partway through.
• •Dump typically in the 140–160 °C range, depending on the polymer and filler system.

Typical second stage (final)

• •Cool the masterbatch completely — this is essential, not optional.
• •Add the curatives (sulphur and accelerators) on a cool mill or at low mixer speed, keeping the batch below roughly 100–110 °C.

The three additions that cause the most trouble

• •Sulphur added too early or too hot — causes scorch and bin scrap.
• •Silane added without a temperature hold — leaves the coupling reaction unfinished.
• •Oil added all at once — the compound becomes too soft to generate the shear needed for dispersion, and the filler never incorporates properly.

Ask your supplier which sequence they use and at what dump temperature. It tells you more about their process control than the data sheet does. ## Need the documents or today's price? Send us the grade, quantity and destination port — we return a quotation with COA and MSDS attached. Email manager@fipolymer.com or use the inquiry form on this site.