A-A-59588 Silicones

SSP makes A-A-59588 silicones and supplies them as sheets, rolls, and ready-to-mold compounds.

This spec is sometimes written as AA-59588 or ZZ-R-765 instead.

Use the tables below to find materials by class. 

You’ll also find more general information about the AA-59588 specification below.

A-A-59588 Silicones: Class 1A and 1B
(AA-59588, ZZ-R-765)

A-A-59588 silicones are military and aerospace silicones that meet the requirements of Class 1A or Class 1B are intended for use where resistance to extremely low temperatures is required. The A-A-59588 specification defines this as approximately -73°C (-100°F). 

Class 1 materials can also resist extreme high temperatures of approximately 210°C (425°F); however, their length of service at high temperatures is less than that of Class 2 materials. Note that Class 1B silicones have low compression set at high temperatures.

SSP2523T | SSP2521T | SSP220 | ssp372

SSP122

SSP122 is a 60-durometer, peroxide-catalyzed, heat-cured silicone elastomer that meets the requirements of A-A-59588, Class IA and 1B, Grade 60. Find out if this silicone rubber is right for your application.

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SSP389

SSP227

SSP227 is a 50-durometer, peroxide-catalyzed, heat-cured silicone elastomer that meets the requirements of A-A-59588, Class IA and Class 1B, Grade 50. Find out if this silicone rubber is right for your application.

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Military and Aerospace Silicones

SSP266

SSP266 is a 70-durometer, peroxide-catalyzed, heat-cured silicone elastomer that meets the requirements of A-A-59588, Class IA and Class 1B, Grade 70. Find out if this silicone rubber is right for your application.

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SSP278

SSP278 is a 40-durometer, peroxide-catalyzed, heat-cured silicone elastomer that meets the requirements of A-A-59588, Class IA and Class 1B, Grade 40. Find out if this silicone rubber is right for your application.

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A-A-59588 Silicones: Class 2A and 2B
(AA-59588, ZZ-R-765)

AA 59588 silicones that meet the requirements of Class 2A or Class 2B resist extreme high temperatures of approximately 219°C (425°F). They also have low temperature resistance, but only to about -62°C (-80°F). Unlike like Class 2A materials, however, Class 2B silicones have low compression set. In other words, they have high resilience.

SSP2523T | SSP2521T | SSP220 | ssp372

SSP220

SSP220 is a 40-durometer, peroxide-catalyzed, heat-cured silicone elastomer that meets the requirements of A-A-59588, Class 2A and Class 2B, Grade 40. Find out if this silicone rubber is right for your application.

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AA 59588 SILICONES | SSP301| SSP1331T | ssp267

SSP301

SSP301 is a 50-durometer, peroxide-catalyzed, heat-cured silicone elastomer that meets the requirements of A-A-59588, Class 2A and Class 2B, Grade 50. Find out if this silicone rubber is right for your application.

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SSP352

SSP352

SSP352 is a 60-durometer silicone that meets AMS 3303 and AA 59588 Class 2A and 2B, Grade 60. It’s supplied in different form factors and colors.

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SSP389

SSP389

SSP389 is a 70-durometer, peroxide-catalyzed, heat-cured silicone elastomer that meets the requirements of A-A-59588, Class 2A and Class 2B, Grade 70. Find out if this silicone rubber is right for your application.

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cargo aircraft silicones | SSP390

SSP390

SSP390 is a 25-durometer, peroxide-catalyzed, heat-cured silicone elastomer that meets the requirements of A-A-59588, Class 2A and Class 2B, Grade 25. Find out if this silicone rubber is right for your application.

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SSP2523T | SSP2521T | SSP220 | ssp372

SSP391

SSP391 is an 80-durometer, peroxide-catalyzed, heat-cured silicone elastomer that meets the requirements of A-A-59588, Class 2A and Class 2B, Grade 80. Find out if this silicone rubber is right for your application.

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A-A-59588 Silicones: Class 3A and 3B
(AA-59588, ZZ-R-765)

AA 59588 Class 3A silicones provide resistance to extremely low temperatures of approximately -75°C (-103°F). Importantly, these military and aerospace silicones also resist tearing and flexing. AA59588 Class 3A silicones also resist extreme high temperature environments to approximately 204°C (400°F). Applications include engine mounts and exhaust hangars.

A-A-59588 Class 3B silicones also resist tearing and flexing, but their resistance to extreme low temperature is less than that of Class 3A materials. With A-A-59588 silicones that meet the requirements of Class 3B, the temperature range is approximately between -70°C (-95°F) and 204°C (400°F). Applications include aircraft door seals, window seals, and vibration mounts.

SSP200T

SSP200-T, military silicones, aerospace silicones, automotive silicones, fatigue testing, flex-fatigue resistance, demattia flex resistance text, a-a 59588 Class B Grade 50

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SSP2523T | SSP2521T | SSP220 | ssp372

SSP2521T

SSP2521-T is a 70-durometer silicone that meets all A-A-59588, Class 3B, Grade 70 requirements and passes the DeMattia Flex Resistance Test.

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SSP2523T | SSP2521T | SSP220 | ssp372

SSP2523T

SSP2523-T is a 50-durometer, low-temperature, high tear strength, heat-cured silicone with flex resistance that meets A-A-59588, Class 3A, Grade 50.

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SSP389

SSP392T

SSP392-T is a 60-durometer silicone that meets all A-A-59588, Class 3B, Grade 60 requirements and passes the DeMattia Flex Resistance Test.

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Why You Need 3B Certified Silicones with High Flex-Fatigue Resistance

Some suppliers claim that their silicones are flex-fatigue resistant, but industry-wide compliance has been inconsistent. Other suppliers say that their products meet the A-A-59588 3B standard, but their elastomers are not certified to meet the flexural requirements of 3B.

Specialty Silicone Products (SSP) supplies aerospace and military silicones that have been independently-tested and certified to the flexural requirements of A-A-59588, Class 3B for several grades. To our knowledge, SSP is the only manufacturer that certifies materials to this specification with a third-party verification and no exceptions for flex-testing.

SSP will flex-test competitive products at no charge, and encourages sourcing managers and product engineers to choose compounds that pass the DeMattia Flexural Test.

The DeMattia Flexural Text

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. The ASTM D813 – 07(2014) Standard Test Method for Rubber Deterioration–Crack Growth defines this testing protocol.

The DeMattia Flexural Test is one of several fatigue tests, but it’s a critical one for demanding applications. For example, aerospace engineers need silicones with high flex-fatigue resistance for door seals, window seals, and vibration-isolating mounts used with alternators, compressors, and assembly bolts. 

A-A-59588 Classes and Grades

A-A-59588 is a U.S. General Service Administration (GSA) specification that supercedes ZZ R 765. Sometimes, these standards are written as AA-59588 or AA 59588, or as ZZ-R-765 or ZZ-R-765/GEN. ZZ R 765 still appears on some prints, but it’s an older standard referenced by National Stock Number (NSN) 5330-01-371-7183 to ensure standardization among military buyers in NATO countries.   

AA 59599 divides aircraft silicones and aviation silicones into six classes, each with durometer-based grades on the Shore A scale. These spec-grade materials are valued for their resistance to high temperatures, low temperatures, tear, and flex fatigue. 

Flex, or flexural fatigue, is cracking caused by cyclical stresses and strains. Small cracks propagate into larger cracks that, ultimately, can result in failure. Fully-compliant materials must pass the DeMattia Flex Resistance test, which measures crack growth in inches over thousands of flexural cycles.

The table below provides an overview of AA 59588 silicones that are used in aircraft parts like engine mounts, vibration-isolating mounts, and exhaust hangers. Other suppliers claim that their materials are compliant, but SSP makes aircraft silicones  and aviation silicones that meet more than just non-flexural (e.g., tensile strength) requirements.

Class

Description

Grades

1A

Low temperature resistant

40, 50, 60, 70, 80

1B

Low temperature resistant and low compression set at high temperature

 

2A

High temperature resistant

40, 50, 60, 70, 80

2B

High temperance resistant and low compression set

40, 50, 60, 70, 80

3A

Low temperature, tear and flex resistant

30, 50, 60

3B

Tear and flex resistant

30, 50, 60, 70, 80

Comparing A-A-59588 Aerospace Silicones

SSP makes A-A-59588 silicones and supplies them as sheets, rolls, and ready-to-mold compounds. 

Elastomer

A-A-59588 Callouts

Product Specifications

Product No.

Class

Grade

Durometer (Shore A)

Tensile Strength (psi)

Elongation (%)

SSP2523T

3A

50

50

1493

807

SSP200T

3B

50

50

1280

660

SSP392T

3B

60

60

1280

650

SSP2521T

3B

70

70

1238

462

      

SSP390

2A, 2B

25

10 – 80

870 – 1475

700 – 1200

SSP220

2A, 2B

40

40

N/A

N/A

SSP301

2A, 2B

50

50

1100

450

SSP352

2A, 2B

60

60

1000

300

SSP389

2A, 2B

70

70

1000

250

SSP391

2A, 2B

80

80

1200

150

      

SSP278

1A, 1B

40

40

1000

500

SSP227

1A, 1B

50

50

1300

500

SSP122

1A, 1B

60

60

1100

500

SSP266

1A, 1B

70

70

1100

450

 

A-A-59588 vs. ZZ-R-765

The A-A-59588 specification replaced ZZ-R-765E and is sometimes written as MIL SPEC AA-59588, AA 59588, AA59588, or A A 59588 instead.

Specification

Alternative Spellings

Descriptions

A-A-59588

AA-59588
AA 59588
AA-59588
A A 59588

See tables above

ZZ-R-765

ZZR765,
ZZ R 765

Class 1 Extreme low temperature phenyl base silicone

ZZ-R-765

ZZR765,
ZZ R 765

Class 2 General purpose, low compression set methyl-vinyl silicone

ZZ-R-765

ZZR765,
ZZ R 765

Class 3 High flex, high tear strength grades of methyl-vinyl silicone