Often customers ask the question, “What is the shelf-life of your molded silicone keypads & components”, and the answer isn’t always as straight forward as you’d think. There are some important factors that the manufacturer of the device that uses the silicone rubber needs to consider, as well as some guidelines in place for proper storage and general speculations on approximate shelf life. Ultimately it falls on that manufacturer to determine the shelf life of their silicone rubber products.
First we need to know exactly what Shelf life is. Shelf life is the length of time for which an item remains usable, fit for consumption or saleable. This is not to be confused with Service life, which is the time of use in service.
The Society of Aerospace Engineers or SAE for short released document ARP5316 back in 1998 that gives some recommended practices for the storage of elastomers as well as recommended shelf life. The biggest conditions to take into consideration when storing your silicone rubber components are: Temperature, Humidity, and Light.
Per ARP5316, the recommended storage temperature should be between 59 – 100 degrees Fahrenheit. The optimal temperature is approximately 68 degrees Fahrenheit. ARP5316 also discusses the recommended humidity for elastomers. It states “The relative humidity shall be such that given the variations of temperature in storage, condensation does not occur. In any event, if the elastomers are not stored in sealed moisture proof bags, the relative humidity of the atmosphere in storage shall be less than 75% r h.” The last of the main three for storage is light. Silicone rubber should be stored away from direct light. This includes direct sunlight, and even intense artificial lighting. This means that the optimal storage for Silicone rubber products will be in a moisture proof sealed bag, stored in an optimal temperature environment kept away from direct light sources.
All of the silicone rubber types listed within ARP5316 are classified as Unlimited under the Maximum storage life column which is measured in years. Other publications throughout the years have put a year cap of 20 years on silicone rubbers. These recommended shelf lives are nothing more than that. A recommendation. Shelf lives will vary depending on specific product specifications and requirements for physical properties.
At SiTECH, we have a vast knowledge and experience dealing with the liquid silicone rubber. If you have any questions or would like to discuss your silicone rubber needs please call us at 757-887-8488 or simply submit a quote online here.