A method for specifying rubber materials can be found in ASTM D2000 and BS 5176. These provide a full framework covering all rubbers and rubber properties. The relevant requirements for an application are selected from within the framework and are expressed in the form of a “line call out”. (The same framework is used in both ASTM D2000 and BS 5176).

An example of a line call out is BS 5176 1MBC514 F2 7Z1. This can be broken down as follows indicated in this table:

The appropriate table for Grade 1 MBC materials shows the following basic requirements:

• Test: Elongation at Break
• Requirement: 400% minimum
• Test: Heat Resistance (70 hrs @ 100°C)
• Requirement: T.S. ± 30%, E.B. -50% max, Hardness ±15° max
• Test: Oil Resistance (Oil no.3 70 hrs @ 100°C)
• Requirement: Volume change + 120% max
• Test: Compression Set (22 hrs @ 100°C)
• Requirement: 80% max

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