First conformal coating to meet ASTM E595 and Mil-Std 883

Dymax 9771 dual-cure light and moisture cure conformal coating is now available from Intertronics. This low outgassing material is, states the company, “the first conformal coating that meets ASTM E595 and Mil-Std 883 and is therefore suitable for the aerospace and defence markets in applications including missile, satellite, and space critical printed circuit board assemblies”. This coating has UL 94 V0 flammability rating, UL 746E recognised and has low ionic content.

Full cure delivered

Dymax 9771 is formulated to cure with UV light, with a secondary moisture cure mechanism to ensure all material, including any that flows underneath components on a PCB, fully cures. It is engineered for coating thickness of up to 0.20mm, has a low ionic content and meets low outgassing standard test ASTM E595, meaning it provides a cleaner PCB assembly during extreme conditions.

This testing is run at 125°C under a 5 X 10-5 Torr vacuum for 24 hours and total weight loss, collected condensable volatile material and water vapor recovered are measured.

Under heat or vacuum, materials can emit gas in a process known as outgassing. This can be a concern to aerospace and defence businesses as it could indicate decomposition or structural change in a material, contaminate a surface that must remain clean to retain its electrical properties, contaminate the environment the part is in or indicate corrosion, or other surface weakening mechanisms. ASTM E595 is a standard test method to determine volatile contents of materials under vacuum.

Passing the tests

Dymax 9771 passes the following Mil-Std 883 Method 5011.7 tests: thermal stability and filler content via thermogravimetric analysis, specific ion content, total ionic content, hydrogen ion content (pH), and volume resistivity.

Mil-Std 883 method 5011 is a military test standard that establishes uniform methods, controls, and procedures for testing microelectronic devices. It includes procedures to test electronic devices for military and aerospace electronics systems, including mechanical, electrical and environmental tests to determine quality and reliability, to ensure the product is suitable for its intended end use.

"This means military and defence product manufacturers finally have a conformal coating which meets the required standards ASTM E595 & MIL-STD 883," states Intertronics.