# PU Sealant Shelf Life and Storage Conditions

> How to store PU sealant, read shelf life, judge an opened cartridge and avoid moisture, heat and freezing damage before the batch is used.

Updated: 2026-11-14 · Source: https://karmindadhesive.com/resources/pu-sealant-shelf-life-storage/

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

1. Check the batch number, production date and expiry date against the delivery note.
2. Inspect cartons, cartridges and seals for damage.
3. Store in a dry, shaded area within the TDS range.
4. Record the location and date; rotate stock.
5. Keep a retained sample from each batch.
6. 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.