What Are The Characteristics of Non-Post-Cure Liquid Silicone Rubber (LSR)?
Non-Post-Cure Liquid Silicone Rubber (LSR) is a specialized type of silicone elastomer designed to achieve optimal properties without requiring a secondary curing (post-curing) step. This makes it highly efficient for high-volume manufacturing, particularly in medical, automotive, and consumer goods industries. Below are its key characteristics:
1. Single-Step Cure Process
No Secondary Curing Needed: Unlike conventional LSR, which requires post-curing (typically 1–4 hours at 150–200°C) to remove volatiles and enhance properties, non-post-cure LSR achieves full performance directly after primary molding.
Faster Production Cycles: Eliminates post-cure downtime, boosting manufacturing efficiency.
2. Low Volatile Content
Minimal Off-Gassing: Formulated to reduce volatile siloxanes and other byproducts during primary curing, ensuring compliance with medical and food-contact standards (e.g., FDA, ISO 10993).
Suitable for Sensitive Applications: Ideal for medical devices (e.g., catheter balloons, seals) where residual volatiles could compromise biocompatibility.
3. Excellent Mechanical Properties
High Tear Strength & Elasticity: Retains durability and flexibility comparable to post-cured LSR, with typical Shore A hardness ranges of 10–50.
Low Compression Set: Resists permanent deformation after repeated compression (critical for seals and gaskets).
4. Thermal and Chemical Stability
Wide Temperature Range: Performs from -50°C to +200°C without degradation.
Resistance to Sterilization: Withstands autoclaving, gamma irradiation, and EtO sterilization-key for medical components.
5. Biocompatibility and Safety
Medical-Grade Options: Platinum-catalyzed formulations meet USP Class VI, ISO 10993, and EU MDR standards.
No Peroxide Byproducts: Unlike peroxide-cured LSR, avoids potential irritants.
6. Precision Molding Capabilities
Thin-Wall Molding: Flows easily into intricate molds (e.g., microfluidic devices, balloon catheters).
Low Viscosity: Enables injection into complex geometries with minimal voids.
7.Comparison: Non-Post-Cure vs. Traditional LSR
| Property | Non-Post-Cure LSR | Traditional LSR |
|---|---|---|
| Curing Process | Single-step (oven/microwave) | Primary + Post-Cure |
| Volatiles | <0.5% | 1–2% (requires post-cure removal) |
| Production Speed | Faster (no post-cure delay) | Slower |
| Cost Efficiency | Higher (energy/time savings) | Lower |