ELASTOSIL® P 7670 A/B and MinghuiLink RTV-4105 are both very soft addition-cure silicones. P 7670 offers lower published viscosity and 600% elongation, while RTV-4105 is slightly softer, provides a longer working window and has substantially higher published tear strength.
Addition-Cure Silicone
Platinum-Cure Silicone
ELASTOSIL® P 7670 A/B and RTV-4105 are both very soft silicones, but they favor different priorities. P 7670 is better aligned with low-viscosity processing, high stretch and prosthetic or orthotic applications, while RTV-4105 offers slightly lower hardness, longer working time and substantially higher tear strength for soft mold making and delicate parts.
ELASTOSIL® P 7670 A/B and RTV-4105 are both very soft addition-cure silicones. P 7670 is approximately 7 Shore A, while RTV-4105 is 5±1 Shore A, making RTV-4105 slightly softer.
Both use a 1:1 mixing ratio. P 7670 has a 20-minute pot life at 23°C, compared with approximately 30–40 minutes for RTV-4105. RTV-4105 therefore provides more processing time, while P 7670 offers a shorter working cycle.
Viscosity favors P 7670. WACKER publishes approximately 1,800 mPa·s for both components, compared with approximately 4,000 mPa·s Part A and 2,800 mPa·s Part B for RTV-4105. The lower viscosity of P 7670 can support easier flow and filling of fine features.
Mechanical performance is mixed. P 7670 publishes 1.8 MPa tensile strength, 2.1 N/mm tear strength and 600% elongation, while RTV-4105 publishes 2.0±0.5 MPa, 11±0.5 N/mm and 540±50%, respectively. RTV-4105 has substantially higher published tear strength, while P 7670 offers slightly higher elongation.
WACKER specifically positions P 7670 for orthotics, prosthetics and skin-contact flexible applications. RTV-4105 is positioned more broadly for soft molds and delicate reproductions. For thin or repeatedly handled parts, RTV-4105’s higher published tear strength may be advantageous, while P 7670 is attractive where low viscosity, softness and stretch are the priority.
| Technical Parameter | WACKER ELASTOSIL® P 7670 A/B | MinghuiLink RTV-4105 |
|---|---|---|
| Silicone Type | Addition-cure RTV-2 | Platinum-cure silicone |
| Mix Ratio | 1:1 by weight | 1:1 by weight or volume |
| Shore Hardness | Approx. 7 Shore A | 5±1 Shore A |
| Viscosity | 1,800 mPa·s (Part A) | 4,000±200 mPa·s (Part A) |
| Working / Pot Life | 20 min @ 23°C | 30–40 min |
| Demold / Cure Time | Rapid room-temperature cure; conditions depend on part size and thickness | 4–5 h cure |
| Tensile Strength | 1.8 MPa | 2.0±0.5 MPa |
| Tear Strength | 2.1 N/mm | 11±0.5 N/mm |
| Elongation | 600% | 540±50% |
| Shrinkage | Not publicly listed | ≤0.1% |
| Typical Applications | Orthotics, prosthetics, skin-contact applications and flexible components | Soft mold making, delicate reproductions and flexible molds |
| Technical Data Sources | ELASTOSIL® P 7670 A/B | RTV-4105 |
| Key Factor | WACKER ELASTOSIL® P 7670 A/B | MinghuiLink RTV-4105 | What It Means |
|---|---|---|---|
| Hardness | Approx. 7 Shore A | 5±1 Shore A | RTV-4105 is slightly softer. |
| Working Time | 20 min | 30–40 min | RTV-4105 provides a longer processing window. |
| Component Viscosity | 1,800 / 1,800 mPa·s | 4,000 / 2,800 mPa·s | P 7670 has substantially lower and more balanced component viscosity. |
| Tensile Strength | 1.8 MPa | 2.0±0.5 MPa | The published tensile values are relatively close. |
| Tear Strength | 2.1 N/mm | 11±0.5 N/mm | RTV-4105 has a substantially higher published tear-strength value. |
| Elongation | 600% | 540±50% | P 7670 publishes higher elongation and stretch capability. |
| Application Positioning | Orthotics, prosthetics and skin-contact flexible components | Soft molds and delicate reproductions | P 7670 has stronger prosthetic and orthotic positioning, while RTV-4105 is more mold-making focused. |
| Application | ELASTOSIL® P 7670 A/B | RTV-4105 |
|---|---|---|
| Soft Flexible Molds | Strong candidate | Strong candidate |
| Delicate Reproduction | Strong candidate | Strong candidate |
| Undercut Reproduction | Strong candidate | Strong candidate |
| Prosthetic Applications | Strong candidate | Suitable |
| Orthotics | Strong candidate | Suitable |
| Skin-Contact Applications | Strong candidate | Suitable with application-specific validation |
| Thin Mold Edges | Suitable with design consideration | Strong candidate |
| Repeated Manual Handling | Suitable with design consideration | Strong candidate |
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Competitor specifications are based on publicly available manufacturer documentation, with links to the original sources where available. Missing values are shown as “Not publicly listed” and are not estimated or inferred. Specifications may change, so always check the latest manufacturer documentation and conduct application-specific testing before production use. Product names and trademarks belong to their respective owners. This comparison is provided for technical and informational purposes only and is not endorsed by the brands mentioned.