Silicone Sponge Rubber Guide
silicone sponges have outstanding mechanical qualities and are regarded to have a full closed cell structure. Silicone sponge frequently provides greater water sealing in wash-down applications as opposed to silicone foam.
What is Silicone Sponge?
Silicone sponge is utilized by the food processing, medical and pharmaceutical sectors for sealing purposes. Blending the lightness of foam with heavier sponge rubber's increased sealing characteristics, silicone sponge is a very flexible material.
The silicone elastomer is expanded at the moment it is heat cured; the expansion process forms the closed cell sponge structure. The expanding process may be compared to adding yeast to bread to make it rise, generating compressible air pockets. Expanded closed cell silicone sponge materials offer many of the benefits of solid silicone in a softer and more responsive form.
Properties of Silicone Sponge
Silicone itself is exceptionally temperature resistant, being able to endure both high temperatures and those that are considerably below freezing. Silicone sponge has a dense cell structure which provides significant protection against water and particles.
In addition, the silicone sponge offers exceptional vibration isolation properties as well as being able to decrease the impacts of shocks to the item it is protecting.
On the negative side, Silicone has a low tear factor, which implies that it can rip quickly. This renders it unsuitable for dynamic applications. Silicone sponge is also very inert and should not be used with chemicals, notably oil.
Uses of Silicone Sponge
Silicon sponge is widely used outside for sealing off and shielding lighting, communications and electronics equipment from the outside environment. This is owing to its capacity to inhibit wind-driven rain and tiny particles from getting through and harming the equipment.
Owing to the metal detecting silicone employed in its creation, silicone sponges are widely utilized as seals on the production line where contamination must be prevented. This is because a small quantity of particles from degraded silicone seals that enter the production process can contaminate the items being created on the production line. This might result in thousands of pounds being wasted owing to interrupting production and tainted items being returned.
Particles from the silicone sponge may be detected by sensors on the manufacturing line, enabling for a prompt stoppage and repairs to be done in a short amount of time. This immediately reduces down the amount of time and money lost while the machinery is out of work.
Open-cell Vs Closed-cell Sponge Silicone Rubber
It is vital when selecting any sort of silicone sponge to appreciate the distinction between open and closed cells. Puzzling the two might create disappointment in a seal or gasket in the application.
Open Cell Sponge Silicone Rubber
Open cell basically suggests that every cell, or an air pocket, is extensively linked with the subsequent cell. These cells are not finished terminations, in this manner, water, dampness, and residue might advance into the cell structure.
A certifiable instance of an open-cell sponge is the sort of sponge that is used to wash basic household objects. In the case that you place the wipe in a basin of water, you notice the wipe dousing up heaps of water which is subsequently squeezed out again onto the car. The water is permitted to travel through every cell and along these lines gets retained and kept inside the sponge.
Closed Cell Sponge Silicone Rubber
A closed cell sponge has a radically different cell structure than an open cell. In a closed-cell silicone sponge, each cell contains air in a completed and closed pocket. Water, humidity, and other deposits cannot penetrate any of the cells. For any sort of sealing needs, closed cell sponge is exceptionally suitable for usage as it has extremely low water intake keeping the water or any other fluid/material entirely isolated.
The main distinction between an open cell and a closed cell sponge is the toughness and pressure rate. A closed cell sponge will be substantially stiffer. In an open-cell sponge, the air may escape away when pushed and the major defiance comes from the rubber itself.
Silicone Sponge Material Applications
- General Sealing in different Industries/Custom Gasket Applications
- Sound and Vibration Insulation
- Hot & Cold Thermal Insulation
- Cushioning
- Insulating/Lighting Fixture Gasket/Electrical Enclosure
- Flame Retardant Sponge
- Food Processing Machinery Seal/Pharmaceutical Equipment
Benefits of Closed Cell Silicone Sponge
- Wide working temperature — Silicone sponge has a temperature range of -100°F to 500°F (-73°C to 260°C).
- Weather sealing — the closed cell construction provides for effective weather sealing with comparatively modest compressive pressures. UL 50 and UL 50E ratings are available.
- Compression set resistance - Silicone has good compression set resistance (ability to rebound to original thickness), especially at higher temperatures, compared to most rubber materials. Low-compression set silicone sponges are available for even greater performance than general-purpose grades.
- UV and ozone resistance - Silicone materials have exceptional UV and ozone resistance due in part to their inorganic backbone. This gives a long-lasting performance.
- Tough — When silicone is required, silicone sponge components provide superior robustness as opposed to silicone foam items.
- Outdoor gasket - Given all the above characteristics, a silicone sponge is a fantastic material option for outdoor conditions, from the Arctic to the desert.
Benefits of Closed Cell Silicone Sponge
Silicone foam is available in both open-cell and closed-cell foam structure
Open cell foam structure permits excellent absorption of water, moisture, and dust – making it perfect in a conventional sponge used for washing automobiles.
- Closed cell foam structure doesn’t accommodate for the absorption of water, moisture, or dust – making it excellent in sealing applications where water and dust need to be kept out. This kind is intrinsically hydrophobic (repels water) (repels water).
Silicone Sponge Vs. Silicone Foam
While both silicone sponge and silicone foam have superior sealing qualities at increased temperatures, there are small variances in the materials. Silicone sponge is compounded and combined on a 2-roll mill and then cured in an oven. Silicone foam is manufactured from a liquid silicone which is extruded and cured in an over. Both are cellular.
| Characteristic | Sponge | Foam |
| Raw Material | Gum-based silicone, mixed and cured in an oven | Liquid silicone extruded and cured in an oven |
| Min Max Use Temp | -73oC +260oC -100oF + 500oF | -51oC +200oC -67oF + 392oF |
| Flammability | UL 94 HBF (horizontal burn formula is available V22-300) | UL 94 V-0 Vertical burn - better flame rating than sponge |
| Compression Set | Good (a lower compression set formula is available V22-210) | Better compression set than a sponge |
| Tensile Strength | High tensile strength; higher material weight | Lower tensile strength than a sponge; lower material weight. Easier to tear by hand. |
| Density | Soft Silicone Sponge = 21-30 PCF (pound/cubic ft) typical Medium Silicone Sponge = 29-33 PCF typical Firm Silicone Sponge = 40 PCF typical | Soft Silicone Foam = 12 PCF typical(pound/cubic ft) Medium Silicone Foam = 22 PCF typical |
| Compression Deflection | Soft Silicone Sponge = 5-9 PSI typical Medium Silicone Sponge = 6-14 PSI typical Firm Silicone Sponge = 12-20 PSI typical | Soft Silicone Foam = 3 PSI typical Medium Silicone Foam = 9 PSI typical |
| Note: The information provided is for reference and the user must determine if a particular | ||
Silicone sponge tends to be greater in density, have stronger rip strength, and has a higher usage temp (up to 500F compared to 392F for silicone foam) (up to 500F compare to 392F for silicone foam) Essentially silicone sponge has greater physical and mechanical qualities than silicone foam.
Silicone foam tends to be softer, lower in density, and has lower compression set properties. Since it includes more air, it provides superior thermal insulation. Silicone foam also provides greater flame retardant qualities which are important in aeronautical applications. Neither substance absorbs much water, therefore silicone "sponge" is frequently a confused descriptor.