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SILBIONE RTV 4420 A + B

SILBIONE RTV 4420 A + B

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Medium-hard to soft 2K Pt silicone with high elongation.

Medium-hard to soft 2K Pt silicone (Shore A 20) with high elongation (650%) — the firmer variant of the Silbione RTV-44 series for liners, pads and prostheses subjected to higher loads

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  • Mixing ratio
  • Networking type
  • Container
  • Number of components
  • consistency
  • Mixing ratio
  • UV resistance
  • Paint has hardened
  • Self-leveling
  • Density (g/cm³)
  • Viscosity uncrosslinked (mPa·s)
  • Electrical insulation
  • Food contact
  • Suitable for medical use
  • Tensile strength (MPa)
  • Elongation at break (%)
  • Tensile strength (N/mm)

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Silicone USP CLASS VI 2K silicone SILBIONE ELKEM Swiss bearing biocompatible FDA RTV Addition Platinum Complete Kit medium hardness high elongation 1:1 Medical-Grade ISO 10993 sterilizable Shore A 20 Prosthetic liner Heel cushion Toe separator RTV 4420 A+B 650%

 
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. Express logistics. Fast and reliable within Switzerland & Europe.

Shipping from Swiss warehouse within 24 hours. Batch certificate. Invoice within 30 days (B2B). Technical support.
Shipping & Delivery

Usually 1 to 3 working days

Availability will be confirmed after order receipt.

Express logistics within Switzerland & Europe.

General Terms and Conditions →

Product data

Internal reference: 40-93839

HS code: 39100000

Internal reference: 40-93839
HS code: 39100000

SILBIONE RTV 4420 A + B
SILBIONE RTV 4420 A + B
Silbione Elkem Silicones SKU 40-93839 ​

Silbione RTV 4420 A & B is a medium-hard to soft 2K Pt silicone (Shore A 20) with high elongation (650%) — the firmer variant of the Silbione RTV 44 series for liners, pads and prostheses subjected to higher loads.

This product line comprises medically approved, sterilizable 2K polyaddition silicone elastomers for prosthetic liners and orthopedic comfort components — very high elasticity, biocompatible. Silbione 4420 is tailored to specific industrial applications — the most important properties and areas of application are listed below.

Medium-hard variant (Shore A 20)

Silbione RTV 4420 is the medium hardness grade of the Silbione RTV-44 series — Shore A 20 with 650% elongation at break and 5 MPa tensile strength. Suitable for applications requiring greater dimensional stability than RTV 4411 (Shore A 11), but still needing high elongation.

Silbione 4420 in figures
Shore A 20
medium-soft
650 %
Elongation at break
5 MPa
Tensile strength
15 N/mm
Tear resistance

What makes Silbione 4420 stand out

Medium hardness (Shore A 20)
A firmer variant than Silbione 4411 — more shape stability.
High elongation at break (650%)
Withstands high mechanical stress in prosthetic applications.
High tensile strength (15 N/mm)
Long service life even under repeated stress.
Good tensile strength (5 MPa)
Robust material for demanding applications.
Sterilizable
Suitable for medical use with sterilization cycles.
Low viscosity (4,000 mPa·s)
Easily pourable into complex geometries.

What is Silbione 4420 used for?

Highly stressed liners
Prosthetic liner with higher shape stability.
High-impact heel cushions
Pressure relief with medium hardness for longer service life.
Heavy-duty toe separators
With higher dimensional stability than 4411.
Orthopedic pads
Custom-made pads in the orthopedic workshop.
Sports and rehabilitation components
Comfort components with medium hardness.
Pressure relief in diabetes care
Medium-hard pads for demanding applications.
Data sheets & safety data sheet
Full TDS and SDS in DE, EN, FR — view or download directly.
To the documents →

processing

1
Prepare the form
Cleanroom conditions — mold clean and dry.
2
Mix 1:1
Mix components by weight. Wear vinyl or nitrile gloves (no latex).
3
Degas
30–50 mbar vacuum for bubble-free liners. Low viscosity (1,500–8,000 mPa·s).
4
Shed
Slowly pour into the mold. Processing time 10–60 min depending on the variant.
5
Networking + Sterilizing
30–60 min at 80–120 °C. Subsequently sterilizable using standard methods.

Recommended accessories

Bluesil Inhibitor 3
Pot life extender for polyaddition silicone systems (Pt-Cure).
View product →

Important instructions

Mixing & Dosage
Stir A and B thoroughly before each use. Use precise dosage in the specified ratio (see table above) — ideally by weight. Incorrect dosage will result in incomplete cross-linking.
Degassing
Degas the mixture under a vacuum of 30–50 mbar. The material expands 3–4 times, then contracts back to its original size after 5–10 minutes. Interrupt the vacuum several times for better degassing.
Avoid inhibitors
Polyaddition silicones are inhibited by: sulfur-vulcanized rubber, tin-catalyzed RTV, amine epoxides, and PVC with tin salts. If in doubt, conduct a preliminary test.
Application advice
SILITECH will advise you on the optimal RTV variant for your application — substrate, hardness, pot life, mechanics. Contact us with your specific application details.

Silbione 4420 compared to related RTV products

Networking system, mechanics, and processing times side by side — all values ​​from the official Elkem TDS. “— " = not specified in the datasheet.

Silbione 4420
Current product		 Silbione 4410 QC →Silbione 4411 →Silbione 4320 →
Networking system2K Polyaddition (Pt)2K Polyaddition (Pt)2K Polyaddition (Pt)2K Polyaddition (Pt) Paste
Mixing ratio1 : 11 : 11 : 11 : 1
ColorTranslucentTranslucent (A) / skin-colored (B)TranslucentWhitish-brown (A) / white (B)
Shore A hardnessA 20A 11A 11A 20
Elongation at break650 %780 %1'000 %200 %
Tensile strength5.0 MPa3.6 MPa3.8 MPa—
Tear resistance15 N/mm14 N/mm12 N/mm7 kN/m
Potting time50 min10 min60 min2 min
demolding time60 min @ 80 °C60 min @ 80 °C30 min @ 120 °C4 min
Mixed viscosity4,000 mPa·s1,500 mPa·s8,000 mPa·spaste
Main applicationHighly stressed linersLiners for leg prosthesesLeg prosthesis linerOrthopedic insoles
Topics & Application Areas
Key terms related to this product. Also useful for our search and filters.
Silicone USP CLASS VI 2K silicone SILBIONE ELKEM Swiss bearing biocompatible FDA RTV Addition Platinum Complete Kit medium hardness high elongation 1:1 Medical-Grade ISO 10993 sterilizable Shore A 20 Prosthetic liner Heel cushion Toe separator RTV 4420 A+B 650%

Technical data for SILBIONE RTV 4420 A + B

All 19 product information 8 Further properties 1 Physical properties 4 Electrical properties 1 Product approvals 2 Mechanical properties 3
Product information
brand Silbione
Manufacturer Elkem Silicones
Mixing ratio 1 : 1
Networking type Addition (Platinum)
Container 200ml + 200ml, 1kg + 1kg, 5kg + 5kg, 25kg + 25kg
Number of components 2K (two-component)
consistency Flowable
Mixing ratio 1:1
Other features
UV resistance No
Physical properties
Paint has hardened Transparent
Self-leveling Yes
Density (g/cm³) 1.07
Viscosity uncrosslinked (mPa·s) 4000
Electrical properties
Electrical insulation No
Product approvals
Food contact Yes
Suitable for medical use Yes
Mechanical properties
Tensile strength (MPa) 5
Elongation at break (%) 650
Tensile strength (N/mm) 15

For binding values, please refer to the technical data sheet (TDS) in the "Documents" tab.

Documents and datasheets

Click on a document for a preview or the download icon for a direct download.

Technical Data Sheets (TDS) 1
Silbione RTV 4420 A - Technical Data Sheet EN.pdf
446 KB
Safety Data Sheets (SDS) 3
Silbione RTV 4420 A - Safety Data Sheet DE.pdf
254 KB
Silbione RTV 4420 A - Fiche de Sécurité FR.pdf
456 KB
Silbione RTV 4420 A - Scheda di Sicurezza IT.pdf
449 KB

Frequently asked questions about Silbione 4420

Practical questions regarding processing and design — answered by SILITECH.

Silbione RTV 4420 A & B: Medium-hard/soft 2-component polyurethane silicone (Shore A 20) with high elongation (650%) — the firmer variant of the Silbione RTV 44 series for liners, pads, and prostheses subjected to higher loads. Main applications include high-load liners, high-load heel cushions, and high-load toe separators.

Polyaddition crosslinking is a two-component silicone chemistry using a platinum catalyst. Component A contains the platinum complex, and component B contains the SiH crosslinker. When mixed, the components crosslink without releasing reaction byproducts—no shrinkage due to outgassing, excellent dimensional accuracy, and low linear shrinkage. Important: Polyaddition silicones are inhibited by various substances—sulfur-vulcanized natural rubbers, tin-catalyzed RTV silicones, amine-catalyzed epoxy resins, and tin-stabilized PVC. In case of doubt, a preliminary test should be carried out.

Thoroughly stir components A and B before each processing step. Measure precisely according to the mixing ratio specified in the TDS (see comparison table above) – ideally by weight. Mix with an electric or pneumatic agitator at low speed (minimize air entrainment). Degas the mixture under vacuum (30–50 mbar) – the material will expand 3–4 times its original volume, bubbles will escape, and the material will settle back after 5–10 minutes. Then slowly pour into the mold from the lowest point to avoid air entrapment. For polyaddition systems, avoid contact with inhibitors (sulfur-based rubber, tin-based RTV, amine epoxides, PVC with tin salts).

Store in the unopened original container in a dry, cool place — typically between +5 and +30 °C, see TDS for exact values. Store components A and B separately; seal airtight after opening. Polyaddition systems are insensitive to moisture, but should be stored in a cool place to maintain pot life. Consult the Safety Data Sheet (SDS) before use.

The comparison table above lists related RTV products with different hardnesses, pot lives, or application profiles. If you are unsure which product is best for you, we would be happy to advise you — contact SILITECH with details of your application (substrate, desired hardness, processing time, mechanical requirements, and durability).

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Product specifications

Product information
Container 200ml + 200ml or 1kg + 1kg or 5kg + 5kg or 25kg + 25kg
brand Silbione
Manufacturer Elkem Silicones
Mixing ratio 1 : 1
Networking type Addition (Platinum)
Number of components 2K (two-component)
consistency Flowable
Mixing ratio 1:1
Other features
UV resistance No
Physical properties
Paint has hardened Transparent
Self-leveling Yes
Density (g/cm³) 1.07
Viscosity uncrosslinked (mPa·s) 4000
Electrical properties
Electrical insulation No
Product approvals
Food contact Yes
Suitable for medical use Yes
Mechanical properties
Tensile strength (MPa) 5
Elongation at break (%) 650
Tensile strength (N/mm) 15
Keywords
Keywords
Silicone USP CLASS VI 2K silicone SILBIONE ELKEM Swiss bearing biocompatible FDA RTV Addition Platinum Complete Kit medium hardness high elongation 1:1 Medical-Grade ISO 10993 sterilizable Shore A 20 Prosthetic liner Heel cushion Toe separator RTV 4420 A+B 650%
Mechanical properties
Shore hardness A20.0 Shore A
Tensile strength5.0 MPa
Elongation at break650.0 %
Tear resistance15.0 kN/m
Linear shrinkage< 0.1 %
processing
Viscosity of mixture4,000 mPa·s
Viscosity Comp. A4,000 mPa·s
Viscosity Comp. B4,000 mPa·s
Pot life at 23°C50.0 min
Physical & Thermal
Density (23°C)1.07 g/cm³
Temperature resistance (duration)-50 to 150 °C
Peak temperature (short-term)150 °C
storage
Shelf life in original packaging12 months
Storage temperature-5 to 30 °C

Documents and datasheets

Safety Data Sheets (SDS) and Technical Data Sheets (TDS) are available for download: