A Guide to Additives in Polyolefins

Pure (unadditized) PP and PE are exposed to heat and mechanical stress during processing, and to UV light, oxygen and friction during use. Over time these factors can lead to problems such as color change, loss of mechanical properties, or processing difficulty. Additives are added to the pellet in small proportions (generally from a few parts per thousand to a few percent) to prevent these problems or to add a specific function.

Antioxidants slow the reaction with oxygen (oxidative degradation) both during high-temperature processing and over the material's service life, preserving its mechanical properties — they are an almost standard additive in polyolefins.

UV stabilizers slow the color fading and loss of mechanical strength caused by sunlight in outdoor applications (agricultural mulch film, exterior products). They are generally not needed for short-life, indoor products such as general-purpose packaging.

Slip additives reduce friction between film surfaces so that films unwind easily from the roll without sticking to themselves — commonly used especially in bags and packaging films.

Anti-block additives create microscopic surface roughness to prevent film layers from sticking together (blocking); they are generally used together with slip additives.

Color additive is generally added not as pure pigment but in masterbatch form (concentrated pigment in a carrier pellet) — this makes dosing and homogeneous distribution easier (see the 'What Is Masterbatch' article).

More specialized additives, such as flame retardants, antistatic agents or impact modifiers, can also be used in certain applications (electrical-electronic housings, sensitive electronics packaging, parts requiring low-temperature performance); such additives generally require a special formulation and are not found in standard general-purpose grades.

The standard PP/PE grades in our catalog are general-purpose formulations that include the manufacturer's baseline stabilization package. For applications requiring a special additive (high UV resistance, flame retardant, etc.), letting us know your requirement helps us jointly identify the right specialty grade.