storage · shelf life · quality
PU Sealant Shelf Life and Storage Conditions
By the Tech Department · Reviewed by Wang · Updated 2026-11-14 · How these notes are made
PU sealant is a reactive material. Moisture-curing PU reacts with water in the air; an unopened pack is protected, but an opened pack is not. Storage is therefore part of the product specification, not a warehouse detail.
1. Read the shelf life correctly
The shelf life on a TDS usually refers to an unopened pack kept within a stated temperature range and away from direct sunlight. It is not a guarantee for a pack that has been opened, stored in a hot container or exposed to humidity.
Record the production date, batch number and expiry date on receipt. Use a first-in, first-out system; a pallet at the back of the store can sit through a hot season while newer stock is used first.
2. Storage conditions
| Factor | Practical rule | Failure mode |
|---|---|---|
| Temperature | Follow the TDS range; avoid hot roofs and direct sun | Faster ageing, skinning, package deformation |
| Humidity | Keep packs closed and dry | Moisture cure starts in the package |
| Freezing | Do not freeze | Package damage, moisture, inconsistent cure |
| Stacking | Follow the carton limit | Deformed cartridges and leaking seals |
| Light | Keep out of direct sunlight | Surface heating and label degradation |
A container parked in the sun can exceed the ambient air temperature. If the goods have been in a hot container for weeks, treat the storage history as unknown and test a sample before production.
3. Opened cartridges
An opened cartridge is a different material state. The nozzle and the cartridge mouth are exposed to air; a skin can form inside the nozzle and a partially cured plug can be pushed into the bead.
Practical rules:
- reseal immediately after use;
- store the cartridge upright and cool;
- do not add solvent or water to revive it;
- discard a cartridge with a cured plug or a lumpy texture;
- test a bead if the cartridge has been open for more than a shift.
Do not mix a suspect opened cartridge with a new one to “use it up”. That is how a small amount of cured material becomes a field failure.
4. Signs that a batch is no longer fit for use
- Skin forms in the nozzle or at the cartridge mouth.
- The paste is lumpy, grainy or has a hard skin.
- The cartridge or sausage has leaked or lost its shape.
- The batch has been stored above the stated temperature or has been frozen.
- The cure section after a test bead is soft or tacky in the centre.
- The label, batch number or expiry date cannot be read.
A visual check is not a cure test. Cut a cured bead and inspect the section; a skin on the outside can hide an uncured core.
5. Receiving and stock control
- Check the batch number, production date and expiry date against the delivery note.
- Inspect cartons, cartridges and seals for damage.
- Store in a dry, shaded area within the TDS range.
- Record the location and date; rotate stock.
- Keep a retained sample from each batch.
- Quarantine any pack with a damaged seal or an unknown storage history.
The practical position
Shelf life is a starting condition, not a performance promise. The older the pack and the more uncertain its storage, the more a bead test matters. A supplier who can state the storage range and batch date is easier to control than one who says “it lasts a year” without a condition.