Re-testing schedules vary significantly depending on the type of nitrile rubber; the specific re-inspection cycle is determined by the material form, storage conditions, and product characteristics.
Re-inspection Requirements by Product Category
Solid Nitrile Rubber (Raw Rubber): The nominal shelf life under standard storage conditions is 6 years. Testing or disposal is recommended if the production date exceeds 2 years to mitigate aging risks.
Nitrile Rubber Bladder Products: The shelf life is typically 3 years from the date of manufacture; if this period is exceeded, visual and performance inspections must be completed before use.
Nitrile Rubber Sealing Products (e.g., O-rings): Nitrile rubber seals with low aging sensitivity have an initial shelf life of 5 years. If this period is exceeded, full-performance testing in accordance with relevant standards is required, and use is permitted only if the product passes.
General Nitrile Rubber Products: The shelf life is 3–5 years under standard storage conditions. For components such as seals held in stock for over 2 years, hardness must be re-tested; a hardness change exceeding 15% necessitates a warning or further assessment.
Additional Re-inspection Requirements for Special Scenarios
If storage conditions do not meet standards (e.g., prolonged exposure to excessive temperatures, light, or oil contamination), key performance indicators must be spot-checked quarterly to detect early signs of aging.
Upon successfully passing full-performance testing, nitrile rubber products may be granted a storage life extension of 1–2 years, after which re-inspection is required to verify their condition.
For industrial-grade products (such as Lanzhou Petrochemical nitrile rubber), users must submit a re-inspection request to the manufacturer within one year of the product leaving the factory if there are concerns regarding quality.
