Email LinkSHELF LIFE OF SEALS AND OTHER RUBBER PRODUCTS
As they age, rubber seals and molded products can undergo changes in physical properties and become unusable due to excessive hardening, softening, cracking, crazing, or other surface degradations. These changes may be the result of one particular factor or a combination of factors, such as the action of oxygen, ozone, light, heat, humidity, oils, water, or other solvents. The detrimental effects of these factors can, however, be minimized by proper storage conditions.
Here are some guidelines that will help increase the shelf life of
your rubber products:
TEMPERATURE
The optimum temperature for the storage of rubber products is between 40°F and 80°F. High temperatures do accelerate the deterioration of rubber products, so sources of heat in storage rooms should be arranged such that the temperature of stored items never exceeds 120°F. The effects of low temperatures are not as damaging or permanent as high temperatures, but rubber articles will become stiffer and care should be taken to avoid distorting them at temperatures below 30°F.
HUMIDITY
The relative humidity in the storage area should be below 75%. Very moist or very dry conditions should be avoided. Where ventilation is necessary, it should be kept to a minimum. Condensation should not be allowed to occur.
LIGHT
Rubber products should be protected from light, especially sunlight and strong artificial light with high ultraviolet content. Polyethylene bags stored in large cardboard containers and polyethylene-lined craft bags offer good protection against light.
OXYGEN AND OZONE
Oxygen (O2) and Ozone (O3) are very damaging to rubber products, so wherever possible, they should be stored in airtight containers to protect them from circulating air. Ozone is particularly damaging, and causes a "scission" of the carbon backbone polymer chain into smaller chains. Seals and other rubber products should be kept away from ozone-generating equipment such as electric motors, mercury vapor lamps, and high voltage electrical equipment.
DEFORMATION
Rubber products should be stored in a relaxed state, free from tension, compression, or other deformation since these may lead to cracking or permanent change of shape. Large O-rings and seals should not be stored on pegs as this may cause severe deterioration.
SHELF LIFE
In normal warehousing conditions, the shelf life of even relatively age-sensitive elastomers is considerable, due in large part to major improvements in compounding techniques. The table at right lists the generally recommended shelf life limitation of the most widely used rubber compounds. The shelf life estimates in this table are fairly conservative.
CURE DATE
All O-rings inventoried and shipped by RL Hudson are stored in either zip-lock or heat sealed plastic bags, and have bar coded labels which indicate the cure date and batch number.
If you have questions about the shelf life or storage conditions of your rubber products, please contact your RL Hudson territory manager or account manager at 1-800-722-6766.
