Remix each of the two components (part A and B) every time before using.

1. Mixing the two components

100 parts of SILBIONE RTV 4428 A add 10 parts of SILBIONE RTV 4428 B. The two components are thoroughly mixed using an electric or pneumatic mixer, working at low speed to limit the inclusion of air in the mixture. In all cases, it is essential to cure the product under correct conditions and to ensure that SILBIONE RTV 4428 A and B both the same batch number. Parts A and B must be matched in order to obtain correct curing.

2. Degassing

After mixing base and catalyst, it is recommended to degas to eliminate entrapped air.
The SILBIONE RTV 4428 is degassed under vacuum pressure of 30 to 50 mbar.
Under vacuum pressure, the product will expand 4 at 5 times its initial volume and forms bubble on its surface.
These bubbles will disappear gradually and the mixture will sink back down to its initial volume within few minutes. Releasing the vacuum once or twice during the operation will improve gas removal.
Remark: release the vacuum several times improves the degassing. For easier degassing only fill a recipient to 1/3 of its height.


3. Making the moulds

This is performed by gravity or under pressure. Since the viscosity of the two products rises relatively slowly, this helps make it easier to process SILBIONE RTV 4428 A and B.

4. Curing
At a temperature of 25 °C, SILBIONE RTV 4428 A and B cures in around 24 hours. Heat helps accelerate curing.
Recommended curing temperatures: 4 hours at 65 °C counted from the time when the or 1 hour at 100 °C whole RTV mass is at the required or 30 minutes at 150 °C temperature

When taking impressions, SILBIONE RTV 4428 A and B may stick to the model. It is therefore advisable to form a barrier between the RTV and the model using a separating agent (e.g. Codex Vaseline grease) applied in a very thin coat.
Make sure that the packaging is hermetically sealed after each use

SILBIONE RTV 4428 A may be stored at temperatures between -5°C / 23°F and 30°C / 86°F for up to 12 months from its date of manufacturing.Please consult the Safety Data Sheet of this product.


SILBIONE RTV 4428 A and B is a two component, silicone elastomer which cures at room temperature by a polyaddition reaction. The cross linking can be accelerated by heating. This RTV Silbione is a fluid paste that once cured, transforms into a strong, elastic material. When correctly cured, SILBIONE RTV 4428 A and B is not notably toxic, and local skin application is generally well tolerated.


2 Part RTV

  • Easy processing due to the good fluidity
  • High tear strength
  • Low linear shrinkage
  • Natural release properties
  • Outstandingly chemically inert
  • Excellent resistance to natural ageing

SILBIONE RTV 4428 A and B is suited to various applications,
especially in the following fields:
PHARMACY: slow-release systems for active ingredients, etc.
PARAMEDICAL: orthopaedics, medical devices in contact with skin, etc

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














hardness_cd523e03-72a3-4261-93f9-36f7bbeeafb1hardness_cd523e03-72a3-4261-93f9-36f7bbeeafb1Hardness28PairedMixISO 868sh.A
tear-strength_a14604f3-602f-4240-a9bf-15d90bbfbd13tear-strength_a14604f3-602f-4240-a9bf-15d90bbfbd13Tear strength> 15PairedMixASTM D 624AKN/m





























Orthotics & Prosthetics & Prosthetics