Synthetic Hydrotalcite

Hydrotalcite (hydroxy carbonate of aluminum magnesium) used as acid scavenger in thermoplastic polymers; it’s particularly suitable for PVC and in the presence of halogen-based flame retardants.

The synthetic hydrotalcite reacts chemically with strong acids during the extrusion process by reducing drastically the free acidity into the polymer. This process protects the polymer from degradation during both the extrusion and molding of the compound.

It is widely used in PVC because, during the processing of this polymer, free hydrochloric acid can be easily generated into the material.

Concerning the other polymers, it’s mainly used in compounds containing halogenated flame retardants. In this case the Hydrotalcite preserves the polymer from the degradation caused by the free acidity due to the presence of halogen based flame retardants.

The synthetic hydrotalcite is very active at low percentages and is generally used around 0.1% depending on the degree of acidity which must neutralize. In PVC compounds the percentages are generally higher than other polymers. Typical addition levels are 0.3% -0.4%..