SILBIONE RTV 4320
SILBIONE RTV 4320 — medical-grade silicone paste for orthopedic insoles. Shore A 20, 1:1, 4-minute cure time.
SILBIONE RTV 4320 — biocompatible two-component silicone paste for orthopedics.
Main applications: orthopedic insoles, heel spur pads, custom-molded foot care components. Shore A 20 (soft, shock-absorbing). 1:1 mix, 2-minute processing time, 4-minute curing time — suitable for chairside use. Medical-grade with FDA/USP Class VI approval. Shipped from our Swiss warehouse.
documents
Internal reference:
40-4320
HS Code:
3910.0000
SILBIONE RTV – biocompatible addition-cure silicones for medical applications
SILBIONE® is Elkem’s premium product line of medical-grade silicones. All products in the family undergo extensive toxicological testing and meet the regulatory requirements of several countries: FDA, USP Class VI, ISO 10993 biocompatibility, and various pharmacopoeia standards. This makes SILBIONE the first choice wherever silicone comes into direct or indirect contact with the skin or is used in medical devices.
The curing mechanism is consistently addition-curing (platinum): no byproducts, high chemical purity, and no toxic byproducts during or after curing. All SILBIONE RTV products are sterilizable (autoclave, gamma radiation, ethylene oxide) and can withstand repeated cleaning cycles.
Inhibition Warning
Like all platinum-cured RTVs, SILBIONE products are sensitive to inhibitors. This is particularly important in a medical setting: Latex gloves completely prevent curing— use only vinyl or nitrile gloves without sulfur accelerators! Other inhibitors include sulfur-containing rubbers, amines, tin compounds, and epoxy hardeners.
SILBIONE RTV 4320 in detail – the foot care paste
SILBIONE RTV 4320 A&B is a two-component silicone paste for orthopedic applications, specifically designed for:
- Orthopedic insoles (custom-fit footbeds, metatarsal pads)
- Heel Spur Cush ions with Custom Geometry
- Other foot care products that come into direct contact with the skin during prolonged use
The product is formulated as a paste (non-flowing)—A is white, B is brownish—and is mixed in a 1:1 ratio. The working time is only 2 minutes, and curing is complete after 4 minutes – ideal for chairside use in the orthopedic lab, where the patient takes an impression on the insole and the insole is completed within a single session.
Specifications
| Chemistry | 2K Adhesive (Platinum), 1:1 |
| Color A / B | White / Brownish |
| consistency | Paste (not runny) |
| density | 1.4 g/cm³ |
| Processing time @ 23°C | 2 min |
| Curing at 23°C | 4 min |
| Shore A (after 24 hours) | 20 |
| Tear resistance | 7 kN/m |
| elongation at break | 200% |
| Linear shrinkage | < 0,1 % |
| Biocompatibility | Yes (SILBIONE® Medical Grade) |
processing
- Put on vinyl or nitrile gloves (do not use latex gloves! – the sulfur residues inhibit cross-linking)
- Mix 100 parts of A and 100 parts of B (by weight) until a uniform color is achieved
- Press onto the substrate (plaster cast, direct impression taken from the patient)
- Let it cure for 4 minutes at room temperature, then remove from the mold
Packaging: 25-kg drums for A and B separately. Also available: SILBIONE RTV 4335 (Shore A 35, B in "Neutral" or "Skin" versions) and SILBIONE RTV 4345 B (Shore A 45, beige). The harder variants are used for robust metatarsal pads and heavy-duty insoles.
SILBIONE RTV 4320 is supplied by SILITECH AG with technical support, a batch certificate, a safety data sheet, and shipping from our Swiss warehouse within 24 hours.
Frequently Asked Questions About SILBIONE RTV 4320
Questions about medical-grade silicone paste for orthopedics.
Yes. SILBIONE® is Elkem’s medical-grade product line. The product undergoes toxicological testing and meets the biocompatibility requirements of USP Class VI, ISO 10993, and the FDA. The product is specifically approved for use as an orthopedic insole in direct contact with the skin over extended periods. Please contact us for specific regulatory documentation.
Hardness ratings: 4320 = Shore A 20 (soft, shock absorption, heel spur pads), 4335 = Shore A 35 (medium, standard insole for comfort), 4345 = Shore A 45 (harder, heel cups and corrective inserts for mechanical stress). RTV 4320 is listed in the shop—other variants are available upon request.
Never uselatex gloves! The sulfur in latex prevents the platinum-catalyzed silicone from curing—the product remains sticky and uncured. Use vinyl or nitrile gloves without sulfur accelerators. The same goes for tools: use only clean stainless steel or plastic containers.
Yes, that’s exactly what SILBIONE RTV 4320 is designed for: chairside use. With a working time of 2 minutes and a setting time of 4 minutes, the entire impression procedure is completed in about 10 minutes. The patient places their foot on the fresh paste, the silicone molds to the shape under the weight, sets, and the finished insole can be removed and adjusted immediately.
product specifications
| Physical properties | |
|---|---|
| Paint cured | White |
| Self-leveling | No |
| consistency | Thixotropic |
| product information | |
|---|---|
| container | 1 kg + 1 kg or 5 kg + 5 kg or 25 kg + 25 kg |
| brand | silbione |
| network type | Addition (Platinum) |
| manufacturer | Elkem Silicones |
| Number of components | 2K (two-component) |
| mixing ratio | 1:1 |
| Additional features | |
|---|---|
| UV resistance | No |
| product approvals | |
|---|---|
| food contact | Yes |
| Suitable for medical use | Yes |
| Areas of application | |
|---|---|
| Main application | Mold making or Prototyping |
| Electrical Properties | |
|---|---|
| Electrical insulation | No |
| Uncategorized | |
|---|---|
| Pot life (min) | 2 |
| Entformzeit (min) | 4 |
| Elongation at break (%) | 200 |
| Reißfestigkeit (N/mm) | 7 |
| keywords | |
|---|---|
| keywords | |
| Mechanical properties | |
|---|---|
| Shore A hardness | 20.0 Shore A |
| tensile strength | 2.0 MPa |
| elongation at break | 200.0 % |
| Tear resistance | 7.0 kN/m |
| Linear shrinkage | < 0.1% |
| processing | |
|---|---|
| Pot life at 23°C | 2.0 min |
| demolding time | 4.0 min |
| Physical & Thermal | |
|---|---|
| Density (23°C) | 1.4 g/cm³ |
| Temperature resistance (duration) | -50 to 150 °C |
| Peak temperature (short-term) | 150 °C |
| storage | |
|---|---|
| Shelf life in original packaging | 12 months |
| Storage temperature | -10 to 30 °C |