Backup ring materials for LNG seals include filled PTFE, PEEK, and glass-filled polymers maintaining properties at cryogenic temperatures. Backup rings prevent seal extrusion into clearances under pressure. Material selection must withstand thermal cycling without cracking. Proper backup ring design extends primary seal life and enhances pressure resistance in demanding LNG applications. https://globalsealstech.com/product-category/oil-gas-seals/api-6d-ball-valve-and-lng-seals/