Antimony Trioxide Catalyst

Polymerization Efficiency

Metal particles facilitate the speed at which chains grow in the reactor. Higher levels of the chemical speed up the reaction. Modern plants balance this speed against the energy cost of the vacuum system.

Color Quality

The presence of metal residues can introduce a grey or yellow tint to the final preform. Masking agents are often added to counteract this effect and maintain the high clarity required for beverage packaging. Refined grades of the powder are used to minimize the introduction of impurities that cause haze.

Impurities also act as sites for thermal degradation.

Thermal Stability

Remaining catalyst can promote degradation during the subsequent injection moulding of the preform. Metal ions facilitate the breaking of polymer chains when the resin is held at high temperatures. This reduction in molecular weight weakens the final bottle and increases the levels of acetaldehyde.