Rubber Storage and Aging
Astlett Customer Help Sheet
when properly stored, has a storage life measured in years.
Under international trade practice, rubber less than 12
months old is considered prime tenderable. However, certain
(reversible) changes may take place over time.
be stored in a dry place with no direct exposure to sunlight.
Every effort must be made to keep rubber dry.
and storage at lower temperatures (e.g. <15°C) will
result in crystallization. The lower the temperature,
the faster the crystallization. Fully crystallized rubber
is very hard. This is reversible by conditioning in a
hot room (recommended in any case) and/or by mastication.
hardening occurs over time as spontaneous crosslinking.
This is measurable as increased viscosity. This is reversible
by mastication. Controlled Viscosity (CV) grades harden
much slower than non-controlled rubbers, but all rubbers
packaging is only designed for a one-way trip. Caution
should be used if rubber units are to be stacked.
units are protected by at least two layers of low melt
polyethylene. A thin inner layer wraps each bale. This
layer usually has grade and producer marks. A thick poly
outer shroud gives further protection.
Units of rubber
have various useful marks on their exterior. Shipping
marks establish unique lot identity, the producer, the
importer and destination port. Grade names and symbols
verify the standards used. Serial production lot numbers
are keyed to Certificates of Analysis (for TSR's). Net
and gross weights indicate the quantity.
burn but is not easy to ignite.
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