Remix each of the two components (part A and B) every time before using.
1. Mixing the components
SILBIONE RTV 4420 A&B and SILBIONE RTV 4420 QC A&B are mixed by weight in a fixed ratio given above.
The two components may be thoroughly mixed either by hand or using a low-speed electric or pneumatic mixer to minimise the introduction of air and to avoid any temperature increase.
Note: It is also possible to use a special mixing and dispensing machine for the two silicone components. Further information is available upon request.
2. Degassing
The mixture should be degassed preferably at 30 to 50 mbar to eliminate any entrapped air. If a dispensing machine is used, the two components are degassed separately prior to mixing.
The silicone mixture expands to times of its initial volume and bubbles rise to the surface. The bubbles progressively disappear and the mixture returns to its initial volume after 5 to 10 minutes. Wait a few minutes to complete the degassing and then flash the vacuum. The silicone is ready for pouring, either by gravity or under low pressure.
Note: Flashing the vacuum once or twice accelerates the degassing. It is recommended to use a container with a high diameter / height ratio (3 to 4 times of the initial volume).
3. Polymerization
The system, as indicated in the technical data, polymerises at 23 °C. The curing may be slowed down at lower temperature and contrary accelerated by applying heat.
Note: In general contact with certain materials can inhibit the crosslinking. See list below:
- natural rubbers vulcanised with sulphur,
- RTV elastomers catalysed with metal salts, e.g. tin-compounds,
- PVC stabilised with tin salts and additives,
- epoxy catalysed with amines,
- certain organic solvents, e.g. ketones, alcohols, ether etc.

If doubts exist it’s recommendable to run a quick test with a small quantity of material in order to assess compatibility. Take duly note that cross contamination due to not well cleaned tools or devices is frequently the main causes of inhibition. The best way is to use only dedicated gear when processing polyaddition RTVs.

Avoid discharge into drains, water courses or onto the ground. Store in a cool, dry place with adequate ventilation. Keep away from incompatible materials, open flames, and high temperatures. Avoid contact with oxidizing agents. Suitable containers: Steel drums coated with epoxy-resin.Please consult the Safety Data Sheet of this product.


SILBIONE RTV 4420 A&B and SILBIONE RTV 4420 QC A&B are a two component silicone elastomer that crosslink at room temperature by polyaddition reaction. The polymerisation can be accelerated by heat.
The silicone components are delivered as two component low viscous liquids, which once mixed and cured, transforms into a translucent, elastic and resistant material. Polymerisation occurs without formation of heat.


2 Part RTV


SILBIONE RTV 4420 A&B and SILBIONE RTV 4420 QC A&B polymerise at room temperature () even in the absence of air and moisture. The curing characteristics are independent of the thickness of the parts.

  • Fast mixing and easy processing (1 : 1) due to the low viscosity.
  • Excellent mechanical properties (especially good tear strength).

SILBIONE RTV 4420 A&B and SILBIONE RTV 4420 QC A&B are suitable for producing orthopaedic devices, e.g. damping elements.

Asia Pacific;Europe Middle East Africa;Central and South America;North America

For information about Storage and Shelf Life for this product, please download the Technical Data Sheet.














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Othotics & Prosthetics & Prosthetics










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