Polycarbonate (PC) is an amorphous thermoplastic polymer with excellent toughness characteristics, clarity and heat deflection properties. With the appropriate stabilization package, PC can be used in a vast variety of molded and extruded applications, ranging from interior and exterior automotive parts, lighting, sunglasses, sheet for architectural glazing, and electronic storage media. High process temperatures require excellent thermal stability of colorants and additives.

Stabilization

Ciba® IRGAFOS® 168 offers excellent processing stabilization for polycarbonate resins for all applications.

Polycarbonate for outdoor applications has to be stabilized against the detrimental effects of UV radiation. Ciba offers a wide range of UV absorbers for these purposes. For bulk stabilization, Ciba® TINUVIN® 234 or Ciba® TINUVIN® 329 in combination with a suitable process stabilizer is used. For demanding thin applications like films or coextruded sheets, Ciba® TINUVIN® 1577 provides superior protection; alternatively Ciba® TINUVIN® 360can be used.

Coloration

Polycarbonates are inherently hydrophilic, and as such require pre-drying for trouble free processing. The formulation ingredients that they come into contact with should also be/remain moisture free. An incorrect colorant or color concentrate, used at the wrong concentrations can drastically reduce the mechanical properties and, in extreme circumstances, render the polymer useless. Although there are a relatively large number of polymer soluble colorants that can be used successfully at various concentrations and processing temperatures for Polycarbonate, there are, at present, few organic pigments. Recommended colorants are mostly part of our Ciba® ORACET® range of polymer soluble colorants for Engineering Plastics, as well as some organic pigments in the Ciba® CROMOPHTAL® range of high performance pigments, all offering required heat stability.

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