Proper storage
of elastomers
Proper storage
General information
The service life of elastomer parts can be influenced and altered by many factors, such as light, heat, moisture, oxygen, ozone, etc. The ideal storage temperature is between +5 and +20 degrees Celsius. In general, storage in sealed polyethylene bags is considered optimal.
Properly stored and handled rubber products—except for unvulcanized rubber compounds—usually retain their properties almost unchanged for several years. Most rubber and rubber products change their physical properties when handled improperly or stored under unfavorable conditions.
For example, exposure to heat, moisture, light, oxygen, ozone, solvents, or storage under tension can shorten the service life or render the product unusable due to:
• excessive hardening
• softening
• permanent deformation
• flaking
• cracks
• other surface damage
Storage room
The storage area should be dry, cool, as dust-free as possible, and only moderately ventilated. Outdoor storage without adequate protection from the weather is not permitted. .
Temperature
The storage temperature should be +15°C and must not exceed +25°C, as otherwise the elastomer may harden or its service life may be shortened. Lower temperatures are generally not harmful to rubber products, but the storage temperature should not fall below -10°C. Heavily cooled products must be brought to a temperature above +20°C for a longer period of time before use. Adhesives and solutions must not be stored at temperatures below 0°C, and rubber products made from certain types of chloroprene rubber must not be stored at temperatures below +12°C under certain circumstances.
Moisture
Storage in damp rooms and the formation of condensation must be avoided. Ideally, the humidity in the storage room should be below 65%.
Heating
When heating the storage room, radiators and pipes must be shielded. The heat sources in the storage rooms should be designed so that the elastomer parts are not exposed to direct heat radiation. The distance between the radiator and the stored goods must be at least one meter.
Lighting
Light can damage the products. They should therefore be protected from strong artificial light with a high ultraviolet content and from direct sunlight. Lighting with normal incandescent bulbs is preferable. A red or orange protective coating on the windows of the storage rooms helps to prevent damage from light, but a blue coating should not be used under any circumstances.
Oxygen/ozone
The products must also be protected from strong air currents, especially drafts. This is best achieved by storing them in airtight containers, packaging them, or using other means.
This applies in particular to products such as rubberized fabrics or cellular items, which have a large surface area in relation to their volume. Ozone is particularly harmful to these products. Therefore, there must be no equipment in the storage rooms that generates ozone. This includes, for example, electric motors or other devices that can produce sparks or other electrical discharges.
Vapors and combustion gases that can lead to ozone formation through photochemical processes must be avoided or eliminated at all costs.
Deformation
It is important to ensure that rubber products are stored free of stress, i.e. without tension, pressure, or other deformations, as stress promotes both permanent deformation and cracking.
Note
This excerpt from DIN 7716 only provides an overview of the basic requirements for correct storage. Numerous other factors can influence the quality of the stored items.
The possible storage life of different compounds varies greatly, even under ideal conditions.
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