The following recommendations indicate the most suitable conditions for storing elastomeric items, whether as a single item or composite product.
Storage temperatures should not exceed 50°C. Low temperatures are not permanently harmful provided the rubber items are handled carefully and not distorted. When taken from low temperatures items should be raised to approximately 30°C before they are used.
Optimum humidity is about 65% in a draft-free atmosphere.
Protection from direct sunlight and strong artificial light with a high ultraviolet content is important. Unless packed in opaque containers, it is advisable to cover windows with red or orange screens or coatings.
Elastomeric items should be protected from circulating air wherever possible. As ozone is particularly harmful to rubber, storage rooms should be free from equipment that may give rise to electric sparks or discharge. Wrapping, storage in airtight containers or other suitable means should be used for vulcanised rubber items.
Where possible, rubber items should be stored in a relaxed position, free from tension or compression. Laying the item flat and avoiding suspension or crushing keeps it free from strain and minimises deformation.
Contact with liquids and semi-solid materials, particularly solvents, such as oils or greases should be avoided unless so packed by the manufacturer.
Metals such as manganese, iron and copper, or copper alloys can have a harmful effect on rubber. A layer of paper, polyethylene or cellophane will keep these separated.
Contact with other rubbers or creosotes should be avoided.
Elastomers should be stored for as short a period as possible, and strict stock rotation should be practised.
Organic solvents such as trichloroethylene, carbon tetrachloride and petroleum are the most harmful agents. Soap and water and methylated spirits are the least harmful, and all parts should be dried at room temperature before use.
The table shows the storage life of seal components made from the more common materials under ideal conditions. Storing under less than ideal conditions will reduce the life.
Base polymerCareful inspection of the following should be made before installation after storage:
a. Mechanical damage
b. Permanent distortion
c. Cracks or surface crazing
d. Tackiness or surface softening/hardening
Thin components (less than 1.6mm {1/16in}) tend to be more critically affected.
The appearance of ‘bloom’ is relatively unimportant, except in certain non-toxic applications.
Many properties of rubber make it the ideal material for anti-vibration products. To conserve these properties it’s important that the rubber is protected from environmental conditions, such as light and heat, that might otherwise degrade it. Consideration should also be given to protecting the metal that the rubber is often bonded to, as this can also be affected by these conditions.
As discussed in our previous post regarding rubber compound selection, some additives can be used to protect the rubber against light, heat and chemicals while the compound is in use. This blog is a guide to the measures that should be put in place when storing components prior to use, for them to function properly for a long time.
The storage of rubber products in humid storage rooms should be avoided as, if condensation occurs, damage can be caused to the product. The relative humidity should be below 65%. Solvents, fuels, lubricants, chemicals, acids, brines, disinfectants and any other similar products should not be allowed in the storage room, to prevent any damage occurring. Rubber products made of certain chloroprene rubber types, such as H Mounts, should be stored at temperatures above 12°C.
Rubber products should be stored without tension, compression or any other deformation, as stress promotes a lasting deformation as well as the development of cracks and damage. Rubber solvents should be stored in a special room in compliance with the official regulations for storage and transportation of inflammable liquids.
The storage of rubber to metal parts has to comply to DIN 7716 ( the storage standards guideline for storage of more than 6 months). The storage room should be cool, dry, dust-free and moderately ventilated and the temperature in the storage room can be between –10° C and 20° C. A higher temperature is permitted, but only for a short time and exposure to direct sunlight must be avoided. The components should be protected against constant air supply, especially to protect the rubber against harmful ozone.
Particular metals, especially copper and manganese, have a damaging effect on rubber products. Due to this, rubber products should not be stored directly with these metals but should be protected by packaging or by covering them with a layer of a suitable material, e.g. paper or polyethylene.
The material of the containers and the material for packaging and covering should not contain any damaging ingredients for the rubber products, such as copper or copper-containing alloys, petrol, oil or suchlike. Foils containing softeners are not permitted for use as packaging material. If rubber products have to be powdered, the powder should not contain any harmful ingredients for rubber products. Appropriate materials for powdering purposes are Paris white, talcum powder, fine grained mica flour and rice starch.
Please don’t hesitate to get in touch with our team if you have any more questions regarding correct storage of any rubber or rubber to metal compounds. Alternatively, you can look online at our collection of anti-vibration mounts and vibration control components, for a range of industries including construction, defence, aerospace, rail, automotive and marine.