The density of foamed silicone varies significantly based on the manufacturing process, material formulation, and intended application. Below is a comprehensive breakdown of the typical density ranges you can expect, from ultra-soft grades to firm, structural foams.
1. General Density Overview
The density of silicone foam typically falls between 0.16 g/cm³ and 1.05 g/cm³ .
The general categories are:
Ultra-Low / Soft Grade (0.16 – 0.25 g/cm³): Extremely lightweight and soft with low closure force . Available as low as 0.16 g/cm³ (10 lbs/ft³) .
Medium / General Purpose (0.25 – 0.48 g/cm³): The most common range, balancing compressibility and durability . Standard panels often sit around 0.35 g/cm³ .
High Density / Firm Grade (0.48 – 0.60+ g/cm³): Denser cell structure for higher sealing forces and wear resistance .
Specialty / High-Density Foam (up to 1.05 g/cm³): Some liquid-applied foams have densities similar to solid rubber (>1.0 g/cm³) .
2. Detailed Density Data by Product Standard
The table below summarizes specific density values from various manufacturers and standards (data converted to g/cm³ for direct comparison):
| Grade / Product Name | Density (g/cm³) | Hardness / Type | Key Application / Feature |
|---|---|---|---|
| Soft Silicone Sponge | 0.16 | Low Closure Force | General sealing, low pressure applications |
| GXC-SF1000 | 0.22 | Soft, High Compressibility | Cushioning, low-closure force gaskets |
| Medium Silicone Sponge | 0.25 | Medium Density | Standard industrial sealing |
| Medium-Firm HT-800 | 0.352 | Medium-Firm (22 PCF) | Durable sealing, industrial gaskets |
| GXC-ST800 | 0.35 | Medium Hardness | Electronic isolation, vibration damping |
| Firm Silicone Sponge | 0.39 | Firm | Higher compression resistance |
| GXC-ST840 | 0.45 | Firm | Structural support, flame retardant applications |
| Extra Firm Sponge | 0.53 | Extra Firm (33 PCF) | Structural support, high wear resistance |
| FDA Silicone Sponge | 0.316 | Food Contact | Food processing equipment seals |
| Specialty High Density | 1.05 | Closed Cell | Cure-in-place gaskets (CIPG) for automotive |
3. Academic and Research Data
Research data from peer-reviewed sources shows density values can range from 0.57 to 1.21 g/cm³ depending on the filler content and foaming agents used .
Low density (0.57 – 0.61 g/cm³): Achieved with higher amounts of chemical foaming agents, resulting in larger cells .
Medium density (0.75 – 0.97 g/cm³): Common for conductive or reinforced foams with filler materials .
High density (1.20+ g/cm³): Unfoamed or minimally foamed solid rubber or highly filled compounds .
4. Implications for Applications
When selecting a silicone foam, the density directly correlates with the following physical properties:
Sealing (Low Density 0.16-0.25): Best for dust-proofing and light environmental sealing where closure force is minimal.
Gasketing (Medium Density 0.25-0.45): Ideal for industrial gaskets requiring good compression set resistance and medium clamping forces .
Structural Mounts (High Density 0.45-0.60): Used for heavy-duty vibration isolation or mounting pads requiring high tear strength.
Thermal/Acoustic Insulation: Lower density foams generally provide better insulation per unit weight.
Summary: For most engineering applications, look for densities in the 0.25 – 0.45 g/cm³ range. Choose the 0.16 g/cm³ range for lightweight cushioning, and the 0.45+ g/cm³ range for high durability or structural sealing