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BLUESIL RTV 3318 SPU
2K-Sn silicone specifically for polyurethane casting resin molds.
2K-Sn silicone (Shore A 18, soft) specifically for polyurethane casting resin molds — mass production of PU components with long mold life
Documents
Internal reference:
40-3318SPU
HS code:
39100000
Bluesil RTV 3318 SPU is a 2K sn silicone (Shore A 18, soft) specifically for polyurethane casting resin molds — mass production of PU components with long mold life.
This product line comprises 2K polycondensation silicone elastomers (Sn) specifically designed for serial production in polyurethane casting resin — offering maximum PU resistance, even against exothermically curing systems. RTV 3318 SPU is tailored to specific industrial applications — the most important properties and areas of application are listed below.
Bluesil RTV 3318 SPU is specially formulated for the mass production of PU casting resin components — offering very high resistance to polyurethane resins, even strongly exothermic systems. Available in three hardness levels: Shore A 18 (3318), 30 (3330), and 35 (3335).
What distinguishes the RTV 3318 SPU
What is the RTV 3318 SPU used for?
processing
Recommended accessories
Important instructions
RTV 3318 SPU 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.
RTV 3318 SPU Current product |
RTV 3330 SPU → | RTV 3325 → | RTV 3221 → | |
|---|---|---|---|---|
| Networking system | 2K Condensation (Sn) | 2K Condensation (Sn) | 2K Condensation (Sn) | 2K Condensation (Sn) |
| Mixing ratio | 100 : 5 (CATA SPU) | 100 : 5 (CATA SPU) | 100 : 5 (Cata) | 100 : 5 (Cata) |
| Color | White | Whitish | White | Beige |
| Shore A hardness | A 18 | A 30 | A 25–28 | A 18 |
| Elongation at break | 520 % | 350 % | 440–490 % | 230 % |
| Tensile strength | 3.3 MPa | 3.0 MPa | 4–4.3 MPa | 1.6 MPa |
| Tear resistance | 19 kN/m | 15 kN/m | 21–26 kN/m | — |
| Potting time | 90–150 min | 150 min | 90–150 min (hr) | 30 min (Standard) / 20 min (Fast) |
| demolding time | 24 h | 24 h | 24 h (Standard) / 6 h (Fast) | 24 h (Standard) / 6 h (Fast) |
| Mixed viscosity | 25,000 mPa·s | 35,000 mPa·s | 35,000 mPa·s | 15,000 mPa·s |
| Main application | Polyurethane casting resin molds | PU casting resin serial molds | lost-wax molds | Lost wax casting for art casting |
Technical data for BLUESIL RTV 3318 SPU
| Product information | |
|---|---|
| brand | Bluesil |
| Manufacturer | Elkem Silicones |
| Networking type | Condensation (tin) |
| Container | 1 kg, 5 kg, 20 kg, 200 kg |
| Number of components | 2K (two-component) |
| consistency | Flowable |
| Mixing ratio | 100:5 |
| Other features | |
|---|---|
| UV resistance | No |
| Physical properties | |
|---|---|
| Paint has hardened | Beige |
| Self-leveling | Yes |
| Density (g/cm³) | 1.25 |
| Viscosity uncrosslinked (mPa·s) | 25 |
| Electrical properties | |
|---|---|
| Electrical insulation | No |
| Curing values | |
|---|---|
| Potting time (min) | 150 |
| Demolding time (min) | 24 |
| Product approvals | |
|---|---|
| Food contact | No |
| Suitable for medical use | No |
| Mechanical properties | |
|---|---|
| Tensile strength (MPa) | 2.5 |
| Elongation at break (%) | 350 |
| Tensile strength (N/mm) | 12 |
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) 3
Frequently asked questions about RTV 3318 SPU
Practical questions regarding processing and design — answered by SILITECH.
Bluesil RTV 3318 SPU: 2K tin silicone (Shore A 18, soft) specifically for polyurethane casting resin molds — for the serial production of PU components with a long mold lifespan. Main applications include polyurethane casting resin molds, lost-wax casting processes, and decorative objects.
Polycondensation crosslinking is a two-component silicone chemistry using a tin catalyst. Upon mixing, the components crosslink, releasing alcohol as a byproduct—this can lead to a small linear shrinkage (typically <0.7%). Advantages: Polycondensation silicones are less sensitive to inhibitors than polyaddition systems—they crosslink even in contact with sulfur-vulcanized rubber and are tolerant of many substrates. It is an established, economical industry standard for lost-wax casting, decorative reproduction, and construction.
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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Our technical team will advise you personally on material selection, processing questions, and individual requirements. Quickly and competently.
Product specifications
| Product information | |
|---|---|
| Container | 1kg or 5kg or 20kg or 200kg |
| brand | Bluesil |
| Manufacturer | Elkem Silicones |
| Networking type | Condensation (tin) |
| Number of components | 2K (two-component) |
| consistency | Flowable |
| Mixing ratio | 100:5 |
| Other features | |
|---|---|
| UV resistance | No |
| Physical properties | |
|---|---|
| Paint has hardened | Beige |
| Self-leveling | Yes |
| Density (g/cm³) | 1.25 |
| Viscosity uncrosslinked (mPa·s) | 25 |
| Electrical properties | |
|---|---|
| Electrical insulation | No |
| Curing values | |
|---|---|
| Potting time (min) | 150 |
| Demolding time (min) | 24 |
| Product approvals | |
|---|---|
| Food contact | No |
| Suitable for medical use | No |
| Mechanical properties | |
|---|---|
| Tensile strength (MPa) | 2.5 |
| Elongation at break (%) | 350 |
| Tensile strength (N/mm) | 12 |
| Keywords | |
|---|---|
| Keywords | |
| Mechanical properties | |
|---|---|
| Shore hardness A | 18.0 Shore A |
| Tensile strength | 2.5 MPa |
| Elongation at break | 350.0 % |
| Tear resistance | 12.0 kN/m |
| processing | |
|---|---|
| Viscosity Comp. A | 25,000 mPa·s |
| Pot life at 23°C | 150.0 min |
| demolding time | 1440.0 min |
| Physical & Thermal | |
|---|---|
| Density (23°C) | 1.25 g/cm³ |
| Temperature resistance (duration) | -50 to 200 °C |
| Peak temperature (short-term) | 250 °C |
| storage | |
|---|---|
| Shelf life in original packaging | 12 months |
| Storage temperature | -5 to 30 °C |
Documents and datasheets
Safety Data Sheets (SDS) and Technical Data Sheets (TDS) are available for download:
- Bluesil RTV 3318 SPU - Fiche Technique FR.pdf (180 KB)
- Bluesil RTV 3318 SPU - Fiche de Sécurité FR.pdf (499 KB)
- Bluesil RTV 3318 SPU - Scheda di Sicurezza IT.pdf (492 KB)
- Bluesil RTV 3318 SPU - Safety Data Sheet DE.pdf (296 KB)
- Bluesil RTV 3318 SPU - Technical Data Sheet EN.pdf (457 KB)
- Bluesil RTV 3318 SPU - Technical Data Sheet DE.pdf (173 KB)