A.J. Rubber & Sponge Ltd. has over 45 years of experience specializing in sponge seal and sponge gasket manufacturing producing precision die cut gaskets. Most of the open cell sponge gaskets & closed cell sponge gaskets that we fabricate are utilized in a wide range of industries, across multiple applications. Closed cell sponge rubber, in general, is technically referred to as expanded rubber, especially in the manufacturing of sponge gaskets and sponge seals. Most grades of sponge material are available in soft, medium as well as firm/hard densities. Each specific kind of sponge offers a unique set of physical properties that are different for each sponge type. The standard range of closed cell sponge thicknesses is between 1/16" to 2" thick.

Sponge silicone gaskets, for example, are quite soft when compared to solid silicone gaskets. Sponge silicone gaskets consist of a closed cell structure, which makes silicone sponge the preferred choice for environmental seals and gaskets. The densities of silicone sponges are typically defined by the compression force of deflection in a PSI range compressed by 25%. A range of 2 to 5 PSI compression force of deflection is rated as soft, whereas a range of 14 to 20 PSI is rated as a firm/hard silicone sponge material/silicone sponge gasket. Also referred to as closed cell silicone sponge or expanded silicone, this material comes from an uncured silicone gum source, which then expands to the desired size through a specialized manufacturing process. The phrase “closed cell” means that the cells within the material are structured such that they are not interconnected and, therefore, are not permeable to water. Put another way, closed cell silicone sponge does not absorb water. Silicone sponge often provides superior water sealing in a variety of applications.

Closed cell neoprene sponge gaskets:

Neoprene is a brand name developed by a chemical manufacturing company; falling within a family of synthetic rubbers, it's very commonly used to manufacture closed cell neoprene sponge gaskets for a number of industries. This material provides good resistance to acids, gasoline, and oil, and is well suited for long term outdoor applications such as electrical enclosures and weatherstripping. Closed cell neoprene sponge gaskets have many beneficial properties, including:

  • Temperature operating ranges of -56.7°C to 93.3°C (-70° F to + 200° F).
  • Ozone resistance as well as resistance to many other weather elements (ultraviolet light, sunlight, etc.).
  • Resistance to both natural and synthetic oils as well as other chemicals.
  • Useful over a very wide range of temperatures.
  • Resistance to tears or damage caused by flexing and/or twisting.
  • Resistance to burning (much better than rubbers that are composed of exclusively hydrocarbon chains).

Due to the above characteristics, closed cell neoprene sponge gaskets are useful in many diverse applications including medical equipment manufacturing, aerospace and military equipment manufacturing, and automotive component fabrication, among many others. Closed cell neoprene sponge gaskets are commonly used in devices that are constantly exposed to extreme chemicals, temperatures and other volatile forces. Closed cell neoprene sponge gaskets are often used in the automotive, and oil and gas industries as seals against toxic environments and weather elements including, but not limited to, direct sunlight, ozone exposure, ultraviolet light radiation, rain, hail, sleet or snow. They have become a popular sealing/gasket product in modern applications ranging from clothing to electronic cases.

A.J. Rubber & Sponge Ltd. die cuts, kiss die cuts and applies PSA (pressure sensitive adhesive) to our closed cell neoprene sponge gaskets. Due to their synthetic nature they tend to be superior heat resistors, making them ideal for applications with extremely high temperatures over long periods of time. Closed cell neoprene sponge gaskets have other unique properties for a wide variety of applications:

  • Frequently used in the assembly, fabrication and manufacturing of large engines for airplanes, trucks, cars, buses, trailers and various types of watercraft.
  • Due to their excellent heat resistant property, A.J. Rubber & Sponge Ltd. have supplied a number of manufacturers with closed cell neoprene sponge gaskets to help them tackle problems requiring sealing under high temperatures and enormous pressures for lengthy periods of time.
  • Typically provide a more or less permanent seal for any given application.
  • Closed cell neoprene sponge gaskets are designed stay in one place and provide long-lasting sealing.

For technical data on A.J. Rubber & Sponge Ltds. closed cell neoprene sponge gaskets, please click on the following links:

AJ-42 spec sheetAJ-43 spec sheetAJ121 spec sheet

Closed cell EPDM (ethylene propylene diene monomer rubber) sponge gaskets:

EPDM (ethylene propylene diene monomer rubber) closed cell sponge rubber material offers excellent resistance to ozone and oxidation. It also provides good aging properties and compressibility. This material is used in a variety of outdoor applications such as weatherproofing or electrical enclosures. Temperatures range from -51.1°C to 98.9°C (–60° F to 210° F).

For technical data on A.J. Rubber & Sponge Ltds. closed cell ethylene propylene diene monomer sponge gaskets, please click on the following links:

EPDM-41 spec sheetEPDM-43 spec sheet

Closed cell vinyl nitrile sponge gaskets:

The term that is technically correct when referring to closed cell sponge rubber is “expanded rubber”. Closed cell vinyl nitrile sponge is a derivative of this expanded rubber. In closed cell sponges, the individual cells resemble balloons, where their function is to hold gas as well as prevent moisture from escaping through the structure as long as the wall of the cell remains intact. To manufacture expanded rubber, the raw compounds are mixed using the same type of equipment used to mix solid rubber compounds, with the only difference being the presence of a chemical blowing agent. Under the appropriate heat and pressure, typically provided by the pre-curing or pre-forming process, this chemical blowing additive decomposes and mixes with the rubber compound to generate nitrogen gas. As this reaction occurs, the mixed batch is placed into an oven and allowed to expand into a bun anywhere from 2" to 4" thick. This bun of closed cell sponge rubber is then left to age and, as a consequence, to split into sheets ranging from .062" thick and greater.

The aforementioned blends of closed cell sponge are very versatile, boasting a temperature range of -40°C to 82°C (-40°F to 180°F). These blends of closed cell sponge rubber are then procured as 50 foot continuous rolls to be used in the custom fabrication of gasket and the custom fabrication of seals. Closed cell vinyl nitrile gaskets tend to have a slightly lower density profile than most other closed cell sponge products. And the water absorption properties are slightly higher than closed cell neoprene rubber materials.

For technical data on A.J. Rubber & Sponge Ltds. closed cell vinyl nitrile sponge gaskets, please click on the following link:

AJ310 spec sheet

Closed cell epichlorohydene sponge gaskets:

Closed cell ECH (epichlorohydene) sponge is a type of closed cell sponge material utilized for the manufacturing of seals and gaskets in the automotive industry. Closed cell ECH sponge materials are often incorporated into gaskets specifically for under-the-hood automotive gasket applications. This is because of their ability to handle continuous temperatures of up to 150°C (300°F) in addition to light oil and fuel contact. ECH also has very good resistance to weather, ozone, sunlight and oxidation.

For technical data on A.J. Rubber & Sponge Ltds. closed cell epichlorohydene sponge seals and gaskets, please click on the following link:

aj ECH spec sheet

SBR (styrene butadiene rubber) sponge gaskets:

Styrene butadiene rubber (SBR) sponge is derived from SBR, which is an elastomeric co-polymer that consists of a combination of both styrene and butadiene. SBR (styrene butadiene rubber) features great resistance to abrasion as well as good stability over a range of environments. SBR (styrene butadiene rubber) sponge is also quite resistant to mineral, natural and synthetic oils, fats, aliphatic hydrocarbons, aromatic hydrocarbons and chlorinated hydrocarbons.

SBR (styrene butadiene rubber) transitions into glass at a temperature of approximately -55°C (131°F) [also referred to as the “glass transition temperature”]. This material also has a recommended temperature range of -40°C to 100°C (-40°F to +212 °F). Other common names for SBR (styrene butadiene rubber) include GRS and buna-S or buna S. An elongation percentage of between 450–500% is typical for SBR (styrene butadiene rubber). As a general rule of thumb, SBR (styrene butadiene rubber) is not ozone, sunlight, and rain or otherwise weather resistant. Although SBR (styrene butadiene rubber) sponge gaskets and seals are versatile products, they are not recommended for any sort of electrical application. SBR (styrene butadiene rubber) is a material commonly used in pneumatic tires or tubes, heels and soles, as well as custom gasket manufacturing applications.

For technical data on A.J. Rubber & Sponge Ltds. SBR (styrene butadiene rubber) sponge gaskets, please click on the following link:

AJ8511 spec sheet
Sample Board Material Spec Sheets

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