Two-component, platinum-curing silicone elastomer that cures at room temperature via a polyaddition reaction and whose curing can be accelerated by heat. Very high elongation, low viscosity, sterilizable according to TDS; hardness according to TDS approx. Shore A 20.
SILBIONE RTV 4420 A&B is supplied as two low-viscosity, liquid components and mixed in a 1:1 weight ratio. After curing, it forms an elastic, resistant material; polymerization occurs without heat generation and can be accelerated by heat, e.g., 60 minutes at 80°C according to the Elkem data sheet. Compared to SILBIONE RTV 4411, the viscosity is lower (approx. 4000 mPa·s) and the hardness higher (approx. Shore A 20). According to the Elkem data sheet, it is positioned for heel cushions, toe separators, and liners for limb prostheses.
Regulatory notice
According to the Elkem data sheet, extensive toxicological tests on SILBIONE products have demonstrated sufficient biocompatibility and suitability for the recommended applications; SILBIONE RTV 4420 A and B meet regulatory requirements in several countries and comply with a range of medical and pharmaceutical regulations, according to the Elkem data sheet. We can assist you with selection and approval for medical or skin contact applications.
SILBIONE RTV 4420 in figures
20
Hardness Shore A (DIN 53505, approx.)
650 %
Elongation at break (DIN 53504, approx.)
4'000 mPa·s
Viscosity at 23°C (approx.)
50 min
Pot life at 23°C (approx.)
What makes the SILBIONE RTV 4420 stand out
Shore A hardness approx. 20
According to the Elkem data sheet, the cured elastomer reaches approximately Shore A 20 (DIN 53505).
Very high elasticity
Elongation at break according to TDS approx. 650 % (DIN 53504), tensile strength approx. 5.0 N/mm² (DIN 53504).
Low viscosity
Both components are low-viscosity, with a viscosity of approximately 4000 mPa·s at 23°C. According to TDS, they mix quickly and are easy to process.
Mixing ratio 1:1
Component A (contains Pt) and B (contains SiH) in a weight ratio of 1:1, pot life approx. 50 min at 23°C.
Sterilizable
According to the Elkem data sheet, the material is sterilizable.
Tear resistance
Tear strength according to TDS approx. 15 N/mm (DIN 53515), density approx. 1.07 g/cm³ at 23°C, color translucent.
What is SILBIONE RTV 4420 used for?
Heel cushions
Positioned according to the Elkem data sheet for heel cushions.
Toe separators
Positioned according to the Elkem data sheet for toe separators.
Liners for limb prostheses
Positioned according to the Elkem data sheet for liners of limb prostheses. For medical or skin contact applications, we support you in selection and approval.
Data sheet and safety data sheet
View or download the Technical Data Sheet (TDS) and Safety Data Sheet (SDS).
Processing
1
Mixing
Stir both components thoroughly before use. Mix A and B 1:1 by weight, either by hand or with a slow-running mixer to avoid air entrainment and temperature increase.
2
Degas
Degas the mixture preferably at 30 to 50 mbar. The volume expands to 3 to 4 times its original size; after complete degassing, release the vacuum.
3
Casting
Pour after degassing by gravity or under slight pressure.
4
Curing
Polymerization occurs at 23°C, slows down at lower temperatures, and is accelerated by heat; according to TDS, for example, 60 minutes at 80°C. Avoid contact with inhibitors.
Important Notes
- Crosslinking can be inhibited by contact with certain substances: sulfur-crosslinked natural rubber, RTV-2 silicones catalyzed with metal salts (e.g., tin compounds), PVC stabilized with tin salts, and amine-catalyzed epoxy resins. If in doubt, test the substrate on a small area beforehand.
- The currently valid Elkem data sheet (TDS and SDS) is authoritative, which we will be happy to send you.
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