Home
/
Compounds and Materials
/
Neoprene/EPDM Blend Sponge

Neoprene/EPDM Blend Sponge

Neoprene/EPDM Blend Sponge is a closed-cell elastomeric foam that combines Chloroprene (Neoprene) and Ethylene Propylene Diene Monomer (EPDM) polymers into a single compound. Blending the two rubbers is done to balance out the weaknesses of each: Neoprene contributes flame resistance, chemical stability, and good compression set, while EPDM contributes superior weathering, ozone, UV, and heat resistance at a lower cost than straight Neoprene alone. The result is a versatile, closed-cell sponge suited for outdoor and general-purpose sealing where both durability and value matter. Sponge rubber is generally available in soft, medium, and firm densities; however, COR's Neoprene/EPDM Blend Sponge offering is limited to medium to firm densities, as these are the only options available from our supplier. It performs well across a temperature range of approximately -65°F to 250°F.

Understanding Neoprene/EPDM Blend Sponge

Like other closed-cell sponge rubbers, Neoprene/EPDM Blend Sponge is produced through a heat-curing expansion process that creates a closed-cell structure, as opposed to an open-cell foam. This closed-cell construction limits water absorption and helps the material maintain a consistent seal even after repeated compression.

COR Manufacturing stocks and supplies Neoprene/EPDM Blend Sponge in cord, custom o-rings, and custom extruded profiles, as well as gasket sheet on request, in medium and firm densities. Round sponge cord is stocked in sizes from 0.103" through 1.500", with larger sizes available upon request, subject to minimum order quantities.

Technical Properties

Property	Test Method	Result	Requirement
Compression/Deflection (25% at 0.5 in/min)	ASTM D 1056-91 2C3/4	11.5 psi	9 to 13 psi
Heat Aged Compression/Deflection (7 days @ 158°F)	ASTM D 1056-91 / D 573-88	+11.5% change	+/- 30% max
Compression Set (22 hrs @ RT, 50% deflection 24 hr recovery)	ASTM D 395-89 (94) Method B	9.2%	25% max
Water Absorption (3 min @ 2.5 psi absolute pressure, then 3 min in water @ atmospheric pressure)	ASTM D 1056-91 2C3	+0.697% weight change	5% max
Temperature Range	—	-65°F to 250°F	—

Manufacturing Tolerances

Neoprene/EPDM sponge cord is extruded to BEC3 tolerances. Due to the nature of sponge materials, cross-sectional tolerances are considerably larger than those of solid rubber extrusions.

Advantages of Neoprene/EPDM Blend Sponge

Excellent resistance to weathering, ozone, UV, and sunlight
Good resistance to flame and heat compared to EPDM alone
Low water absorption due to closed-cell structure
Good compression set and resilience after repeated compression
More cost-effective than pure Neoprene
Good resistance to a moderate range of chemicals, oils, and solvents
Good abrasion and tear resistance

Disadvantages of Neoprene/EPDM Blend Sponge

Not as oil and fuel resistant as pure Neoprene
Not suitable for exposure to strong acids, ketones, or aromatic hydrocarbons
Not recommended for food or FDA-regulated applications
Higher cost than standard EPDM alone

Customization

COR can supply custom Neoprene/EPDM Blend Sponge extrusion profiles in many sizes and shapes. Send us your requirements in a dwg., pdf, or even on a napkin, with dimensions, and we can try and quote according to your request.

We can also cold bond Neoprene/EPDM sponge cord into custom diameters and custom-sized endless rings.