Natural rubber is an imperfect material for gaskets. While soft and compressible at room temperature it hardens in the cold and has poor weather resistance. Styrene Butadiene Rubber (SBR) is a manmade alternative that comes in mainly in extruded and sheet form. For gaskets, SBR sheet is inexpensive and performs well in a range of applications. Here’s a closer look.
Properties of SBR Sheet
SBR is an abrasion-resistant elastomer manufactured in hardnesses ranging from 50 to 80 Shore A. (50 is firmer than a pencil eraser while 80 feels like a leather belt.) It’s also less variable than natural rubber.
SBR has good impact strength and tensile strength from 400 to 1,000 psi. Consider fabric-reinforced grades for applications needing higher strength.
For gasket applications, SBR sheet has high resilience and low compression set. It resists acids, brake fluid, and moisture but is attacked by oils and hydrocarbons. Useful temperature range is -40°F to 180°F (-40°C to 82°C) though limits vary by grade.
SBR Sheet Availability
SBR is available in sheet and roll form up to 36” wide. Thicknesses are from 1/64” to 1/4” with wider and thicker sheet available for special order. SBR sheet comes mainly in black, red and gray. For other colors please ask.
Applications for SBR Sheet
SBR is a good choice for applications needing flexibility and abrasion resistance. Examples include:
- Flaps (access doors and panels, seals around doors.)
- Scrapers and wipers (especially those used in low-temperature environments.)
- Lining rubber (Placed over workbenches and in drawers, SBR sheet absorbs impacts and prevents damage to tools and workpieces.)
- Conveyor Belting
- Skirtboards (Rubber strips at the base of walls in high-traffic and washdown environments.)
High resilience and low compression set make it a good two choice for two other types of application:
- Brake system seals
- Gaskets
The Manmade Alternative
Natural rubber would make an excellent gasket material if it didn’t stiffen in low temperatures and had better weather resistance. SBR sheet has similar useful properties – abrasion resistance, resilience, and strength – without the weaknesses. If you’d like to learn more, specialists at Hennig Gasket can help.
