Semi Open Cell EPDM Foam Roll

Semi-Open Cell EPDM Foam Roll for Low-Compression Sealing

Topsun semi-open cell EPDM foam roll is a soft and highly compressible sponge rubber material designed for weatherstripping, lighting seals, HVAC seals, automotive weather seals, cushioning and custom industrial gasket applications.

Semi-open cell EPDM combines the flexibility and easy compression associated with open-cell foam with improved sealing performance when the material is compressed between mating surfaces. This makes it especially useful for irregular gaps, uneven flanges and assemblies where available closing force is limited.

EPDM also provides strong resistance to outdoor weathering, UV exposure and ozone, making semi-open cell EPDM suitable for both indoor and outdoor sealing components. The material can be supplied in roll or sheet form and converted into strips, pads, gaskets and adhesive-backed parts.

Semi-Open Cell EPDM Foam Key Features

• Low compression force: soft foam structure makes the material easier to compress than many traditional medium or firm closed-cell EPDM grades.

• Conforms to irregular surfaces: suitable for variable gaps, uneven flanges and assemblies where consistent surface contact is required.

• Sealing under compression: semi-open cell construction can provide useful air, dust and moisture sealing when correctly compressed.

• Weather resistance: EPDM is suitable for many exterior applications exposed to outdoor conditions.

• UV and ozone resistance: suitable for weatherstripping, lighting, construction and automotive exterior components.

• Flexible recovery: the foam can recover after compression and maintain contact in suitable dynamic or dimensional-gap applications.

• Low-temperature flexibility: the referenced test data records no cracking after the stated -40°C bend test.

• Custom converting: rolls and sheets can be cut, sliced, laminated, adhesive-backed and die-cut according to drawings.

Semi-Open Cell EPDM Foam Product Information

Semi-Open Cell EPDM Foam Technical Specification

The following table retains the technical test data provided with the existing product. Final specifications should be confirmed according to the selected production grade, thickness and application requirements.

Semi-Open Cell EPDM Foam Product Video

What Is Semi-Open Cell EPDM Foam?

Semi-open cell EPDM is a soft sponge rubber material engineered to provide lower compression force than conventional medium or firm closed-cell EPDM foam.

Its cellular structure provides greater conformability, allowing the foam to follow uneven surfaces and variable gaps more easily. When correctly compressed, the material can also provide useful sealing against air, dust and moisture.

This combination makes semi-open cell EPDM particularly useful where a traditional closed-cell sponge would require too much closing force, but a fully open-cell foam would not provide sufficient sealing performance.

EPDM also retains its characteristic resistance to weather, UV and ozone exposure, making the material suitable for automotive, lighting, HVAC, construction and outdoor sealing components.

Semi-Open Cell vs. Closed Cell vs. Open Cell EPDM Foam

Why Use Semi-Open Cell EPDM for Low-Compression Gaskets?

Some assemblies cannot apply enough closing force to compress a firm closed-cell gasket effectively. Examples include thin metal panels, plastic housings, lighting enclosures and lightly clamped flanges.

Semi-open cell EPDM offers a softer compression response, allowing the gasket to conform to the mating surfaces using less force.

When correctly selected and compressed, this can help maintain surface contact across irregular gaps while providing protection against air, dust and moisture.

Semi-Open Cell EPDM for Weatherstripping

Weatherstripping frequently requires a foam material that can compress easily around dimensional variations while maintaining contact after repeated exposure to outdoor conditions.

Semi-open cell EPDM combines low compression with the weather, UV and ozone resistance associated with EPDM, making it suitable for selected exterior doors, access panels, covers and other weather-exposed assemblies.

Semi-Open Cell EPDM for Lighting Seals

Lighting housings and similar assemblies may use thin covers or plastic components that cannot tolerate high gasket compression loads.

A soft semi-open cell EPDM gasket can conform to uneven mating surfaces while reducing the closing force required to maintain contact around the housing.

For outdoor lighting applications, EPDM also provides useful resistance to weather, UV and ozone exposure.

Semi-Open Cell EPDM for HVAC Seals

HVAC housings, access panels and equipment joints often contain dimensional variation or lightweight sheet-metal components.

Semi-open cell EPDM can be considered for suitable HVAC sealing interfaces where soft compression, gap conformability, vibration damping and environmental resistance are required.

Required density, thickness and compression should be selected according to the panel construction, joint geometry and sealing requirement.

Semi-Open Cell EPDM for Automotive Weather Seals

Automotive applications often require foam seals that can follow changing gaps while tolerating vibration, weather exposure and temperature changes.

Semi-open cell EPDM can be used for suitable automotive weather seals, under-hood sealing components, pads, anti-rattle interfaces and custom die-cut gaskets where its tested properties meet the project requirements.

If a project requires a specific automotive specification, flame requirement or material standard, provide the exact requirement for material evaluation.

Typical Semi-Open Cell EPDM Foam Applications

Semi-Open Cell EPDM Foam Roll for Continuous Converting

Roll material is suitable for manufacturers and converters that need continuous EPDM foam for slitting, adhesive lamination, strip production or automated fabrication.

Semi-open cell EPDM can also be supplied as sheets or converted into pre-cut parts according to the finished component dimensions.

Custom EPDM Foam Strips, Gaskets and Adhesive Parts

How to Select Semi-Open Cell EPDM Foam

• Application: weatherstripping, lighting seal, HVAC gasket, automotive seal or industrial enclosure.

• Gap range: provide the minimum and maximum distance between mating surfaces.

• Available closing force: identify whether lightweight panels or plastic components limit compression force.

• Compression requirement: specify the expected foam compression in the finished assembly.

• Density: provide the required density or desired softness where known.

• Thickness: select according to gap range and intended compression.

• Environmental exposure: identify outdoor weather, UV, ozone, temperature, dust and moisture conditions.

• Automotive or flame requirement: provide the exact project standard if applicable.

• Adhesive backing: specify plain foam or adhesive-backed material.

• Finished form: roll, sheet, strip, pad, gasket or die-cut component.

• Estimated quantity: provide sample, trial and production quantities where available.

Topsun EPDM Foam Processing Capabilities

Topsun supplies foam materials together with custom converting services according to customer drawings, dimensions and application requirements.

1. Cutting: foam sheets, rolls and components can be cut according to required dimensions.

2. Slicing: foam materials can be sliced to the required thickness.

3. Lamination: hot-melt film lamination, flame lamination and pressure-sensitive adhesive lamination are available.

4. Laser Cutting: suitable foam shapes can be cut according to digital drawings.

5. Die Cutting: custom gaskets, strips, pads and other repeatable foam components can be manufactured according to customer drawings.

6. Compression Molding: three-dimensional molded foam and foam composite components can be manufactured for suitable applications.

7. Engraving: suitable for tool-box inserts, packaging inserts and custom foam components.

8. Silk-Screen Printing: logos and patterns can be printed on suitable foam surfaces.

9. Adhesive Backing: adhesive and release liner can be applied to suitable EPDM foam for tapes, strips, pads, gaskets and custom parts.

Other Foam Materials Available from Topsun

Topsun supplies EPDM foam, EVA foam, PE foam, XPE foam, IXPE foam, CR foam, neoprene foam, SBR foam, NBR foam, NBR/PVC foam and micro-cell soft PVC foam in sheet, roll and custom converted forms.

About Topsun Foam

Topsun supplies foam materials and customized foam components for automotive, HVAC, lighting, construction, equipment and industrial applications. Customers can provide density, thickness, gap dimensions, compression requirements, drawings and service conditions for product evaluation.

Our facility is located in Changzhou City, Jiangsu Province, China, with convenient access to Shanghai Port for international shipments.

Semi-Open Cell EPDM Foam FAQ

What is semi-open cell EPDM foam?

Semi-open cell EPDM is a soft, highly compressible EPDM sponge material designed to provide lower compression force than many traditional closed-cell grades while still offering useful sealing performance when compressed.

Is semi-open cell EPDM the same as semi-closed cell EPDM?

Suppliers may use semi-open cell and semi-closed cell terminology for similar intermediate cellular structures. The important factors for material selection are the actual compression behavior, recovery, density and sealing performance of the selected grade.

Why choose semi-open cell EPDM instead of closed cell EPDM?

Semi-open cell EPDM is useful when the assembly needs a softer gasket that can conform to irregular surfaces with less closing force. Closed-cell EPDM is generally firmer and better suited to applications requiring a stronger environmental barrier.

Can semi-open cell EPDM provide an air or moisture seal?

Semi-open cell EPDM can provide useful sealing against air, dust and moisture when properly compressed. Final performance depends on the selected grade, foam thickness, compression, gasket width, joint design and surface condition.

Is semi-open cell EPDM suitable for weatherstripping?

Yes. The combination of low compression, conformability and EPDM weather resistance makes the material suitable for many weatherstripping applications.

Can semi-open cell EPDM be used for lighting seals?

Yes. Semi-open cell EPDM can be considered for lighting housings and similar assemblies where a soft gasket is required around uneven surfaces or lightweight covers.

Is semi-open cell EPDM suitable for HVAC seals?

It can be used for suitable HVAC panel, housing and equipment sealing applications where low compression force, gap conformability and weather resistance are required.

Can semi-open cell EPDM be used in automotive applications?

Semi-open cell EPDM can be considered for automotive weather seals, under-hood components, anti-rattle parts and custom gaskets where the selected material meets the specific vehicle component requirements.

What is the tensile strength of the referenced EPDM grade?

The technical table supplied with this product records a tensile strength test result of 0.44 MPa according to GB/T 6344-1996.

What is the elongation of the referenced grade?

The supplied technical table records an elongation test result of 316% according to GB/T 6344-1996.

How does the material perform at low temperature?

The referenced test data records no cracking after a -40°C × 24 hour, 180-degree bend test.

Can adhesive backing be added?

Yes. Adhesive backing can be applied to suitable EPDM foam rolls, strips, pads and gaskets. The substrate and service environment should be provided when selecting the adhesive construction.

Can Topsun die-cut semi-open cell EPDM foam?

Yes. Topsun provides cutting and die-cutting capabilities for suitable foam materials. Custom seals, gaskets, strips, pads and shaped components can be evaluated according to customer drawings.

What information should I provide for material selection?

Please provide the application, minimum and maximum gap, available closing force, required compression, thickness, density if known, environmental exposure, adhesive requirement, project standards, finished dimensions and estimated quantity.

How can I request a semi-open cell EPDM foam sample?

Send your requirements to july@topsunfoam.com, including thickness, density if known, gap dimensions, compression requirement, application and estimated quantity for evaluation.