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

1. Mixing the two components

Add 100 parts of SILBIONE RT FOAM to 100 parts of SILBIONE RT FOAM 4241 B.
Part A and Part B should be thoroughly mixed together. Vigorous and thorough mixing should be maintained for about 30 seconds. The mixed product should then be quickly casted into the desired application site.
For larger volume applications, SILBIONE RT FOAM 4241 A&B has been specifically designed with a favourable 1:1 mix ratio (both by weight or volume) in order to easily suit a robotic dispensing, where mixing is achieved by means of a dynamic mixer.
The type and degree of mixing and shear can significantly affect the cell structure, cure and density of the final foam product.
Handling precaution: Immediately upon mixing SILBIONE FOAM 4241 A&B a chemical reaction takes place that results in the evolution of flammable hydrogen gas.

2. Crosslinking & foaming

The best curing conditions are at . The use of the product at higher temperatures will reduce the pot life and demoulding time. As opposed to this, lower temperatures will increase the pot life and decrease the demoulding time.
At , the cured silicone can be demoulded after the time indicated as “demoulding time” (see Characteristics § 2. Polymerization, page 2).
Be aware that contact with certain materials can inhibit the curing of SILBIONE RT FOAM 4241 A&B:

  • Natural rubbers vulcanised with sulphur.
  • RTV 2 silicone elastomers catalysed with metal salts, e.g. tin-compounds.
  • PVC stabilised with tin salts and additives.
  • Epoxy resins catalysed with amines.

If doubts exit it is 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 cause of inhibition. The best way is to use only dedicated gear when processing polyaddition SILBIONE RT FOAM 4241 A&B.

SILBIONE RT FOAM 4241 A may be stored at a temperature below 40°C / 104°F for up to 12 months from its date of manufacturing.Please consult the Safety Data Sheet of this product.


SILBIONE RT FOAM 4241 A&B is a two component silicone foam which cures at room temperature by a polyaddition reaction.
When the liquid components A and B are thoroughly mixed in a 1:1 ratio, the product expands and cures to a foamed elastomer at room temperature.


2 Part RTV

  • Easy curing: SILBIONE RT FOAM 4241 A&B crosslinks at temperatures above , even in the complete absence of air or humidity.
  • Easy processing thanks to the simple 1:1 mix ratio.
  • Good chemical and temperature resistance.
  • Low hardness (Shore 00).
  • Low compression set.
  • High temperature stability.
  • The material expands without employing ozone depleting CFCs or other related blowing agents.
  • Proven biocompatibility.


  • Cushioning and damping when high temperature variation is involved.
  • Pelottes.


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ColorWhitishPairedCompASTM D 412
Viscosity15000PairedCompNF T 76102mPa.s




ColorTranslucidPairedCompASTM D 412
Viscosity15000PairedCompNF T 76102mPa.s










SILBIONE RT FOAM 4241 BSILBIONE RT FOAM 4241 B/our_offer/Product/90059509/90059508/SILBIONE-RT-FOAM--4241-B
























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