AA 59588 Silicones

AA 59588 Silicones

AA 59588 has six alphanumeric classes. The tables below divide SSP's products into Class 1A and 1B, Class 2 A and 2B, and Class 3A and 3B.


AA 59588 silicones from Specialty Silicone Products (SSP) meet the requirements of AA 59588, a U.S. General Service Administration (GSA) specification that divides silicone rubber in six classes and grades. The grades correspond to a silicone's durometer or hardness on the Shore A scale.

The table below provides an overview of the AA 59588 spec. 





Low temperature resistant

40, 50, 60, 70, 80


Low temperature resistant and low compression set at high temperature



High temperature resistant

40, 50, 60, 70, 80


High temperance resistant and low compression set

40, 50, 60, 70, 80


Low temperature, tear and flex resistant

30, 50, 60


Tear and flex resistant

30, 50, 60, 70, 80


AA 59588 and Flex-Fatigue Resistance

Each A-A-59588 class specifies multiple material properties, but only Classes 3A and 3B include requirements for flex-fatigue resistance. Fully-compliant A-A-59588, Class 3B silicones must pass the DeMattia Flex Resistance Test, a dynamic test that measures crack growth in inches over thousands of flexural cycles.

Other suppliers claim that their silicones meet the A-A-59588 3B standard, but these materials only meet its non-flexural requirements (such as tensile strength). By contrast, SSP supplies elastomers tht have have been independently-tested and certified to meet the flexural requirements of A-A-59588, Class 3B for Grades 50 and 60 (with Class 70 pending). 

Military and Aerospace Applications

Mechanical engineers need silicones with high flex-fatigue resistance for door seals, window seals, and vibration-isolating mounts. They also need  crack-resistant silicones for engine mounts and exhaust hangers. Electrical engineers and electronic designers need silicones that can flexing without cracking in high-performance keypads.