Influences like heat, high shear rates, UV-radiation or chemical attacks are capable to cleave the sensitive chemical bonds within the polymer chains. Due to the cleavage of the polymer chain highly reactive so called “free radicals” are formed, which via a chain reaction damage other, intact polymer chains and thus lead to an avalanche resulting in, e.g. a rapid degradation of the plastics within a short time.

The damage starts already during processing. This, e.g. with polypropylene is initially indicated by an increase of the melt index, with polyethylene and its copolymers crosslinking occurs, so called gels are build up. At the finished plastic part the damage is observed as loss of gloss and a yellowish coloring, which upon time turns into brown. The parts show chalking, get brittle and lose their mechanical stability.

Antioxidants (thermo-stabilizers) are interfering in this reaction circle and stop respectively delay the damaging process. The antioxidants are subdivided, due to their interaction scheme, in two different categories and often combined, because of synergistic effects:

Radical scavengers (sterically hindered phenols and amines).
They are called primary antioxidants because they are interfering in the first step of the polymer degradation and deactivate the radicals.

Hydroperoxide decomposers (phosphites, phosphonites and thio compounds).
They are called secondary antioxidants. Their task is, after peroxides or hydroperoxides have been built up, to interfere and to deactivate them without further damage.

Typical applications:
For all standard applications in the area of injection molding, extrusion as well as blow molding, corresponding masterbatches are available:

• Process-stabilization (e.g. melt-stabilization in case of multiple processing)
• Long-term thermo-stabilization (e.g. automotive applications according to VW-standard)
• Metal-deactivation (e.g. for copper cable jackets)

• Available carrier polymers: PE, PP, PS, PC and PA

Combi Masterbatches e.g. with UV-stabilizers and pigments are available as well.

Standard program/individual adjustments: Beside of our standard program we also develop individual adjustments depending on required specification and quantity.

Food contact: Yes, if applicable with restrictions – please ask for the appropriate documents (product information/food contact approval/declaration of compliance).