WACKER® CATALYST PT 5
WACKER® CATALYST PT 5 is a highly-active platinum catalyst used for the thermal curing of solvent-based and solvent-free, addition-crosslinking silicones.
- Very high and constant catalyst activity
- Medium platinum concentration
- Rapid curing of addition-crosslinking silicone systems
- Miscible with silicones in all proportions
Specific features of WACKER® CATALYST PT 5
WACKER® CATALYST PT 5 is dissolved in a reactive silicone polymer, which is incorporated into the cured rubber during the curing process. Combined with DEHESIVE® silicone polymers, it is excellently suited for providing various substrates, such as paper and films, with a silicone coating that exhibits release properties towards tacky products used in technical, health, hygiene and food sectors.
WACKER® CATALYST PT 5 must be added to the mixture of DEHESIVE®, CRA® modifier and crosslinker. During addition, stirring should be as rapid as possible to avoid local over-concentrations of the platinum catalyst, which cause premature curing indicated by the formation of gel particles ranging in color from brown to black. It is also important that the platinum catalyst is always added as the last component to the homogeneous mixture of polymer and crosslinker.
Suitable materials for mixing vessels, stirrers, pumps, tubes, filters, etc. are stainless steel, polyethylene, polypropylene, Teflon and other fluorine polymers, as well as products coated or lined with these materials. If good catalyst activity is to be maintained, it is essential to avoid deactivation of the platinum catalyst. This may occur as a result of contact with the abovementioned equipment, with the ambient air, with unsuitable rolls in the coating equipment, with the customer's additives, or even with the substrate to be coated. If heavy metals (e.g. lead, copper, zinc, iron, chromium or tin) or sulfurous, nitrogenous or phosphorous organic compounds are present in any of the above materials, curing may be impaired or even prevented.