Shelf life is the period during which a dye or pigment keeps its stated strength, shade and handling properties in its original sealed pack, under the stated storage conditions. It varies by product and form, so always ask the supplier to state it in the technical data sheet.
As a general pattern, pigments and most dye powders are stable for long periods. Liquid dyes and moisture-sensitive dyes, such as reactive dyes, need more care and usually carry shorter shelf lives.
Shelf life matters most for buyers who order in large lots to save on freight, or who hold safety stock. If your stock turns slowly, the stated shelf life should drive your order size as much as the supplier's MOQ.
What makes dyes and pigments age
- Moisture causes caking and, in reactive dyes, slow hydrolysis that cuts strength.
- Heat speeds up chemical change, so containers left in the sun or in hot warehouses age faster.
- Liquid dyes can settle, thicken, freeze, grow mould or lose stability if the biocide runs out.
- Pigment pastes and presscakes can dry out at the surface or separate.
- Open packs absorb moisture and dust, so part-used drums age fastest of all.
Shelf life and retest date
Some suppliers give a fixed shelf life. Others give a retest date, after which the product should be tested before use. A product past its shelf life is not always bad, but you need a test to know.
Agree in the contract how much of the shelf life must remain when goods arrive. A common approach is to ask that most of the stated shelf life is still left at delivery, so you have time to use the stock.
Ask for the manufacturing date and the lot number on every pack. Without them, you cannot tell how old the stock is. Traders sometimes resell old stock, and an old lot can test weak even if the original maker was good. Read how to tell a trader from a manufacturer.
How to protect it
- Specify sealed, moisture-proof inner liners for powders and granules, as covered in how dyes and pigments are packed.
- Ask for the storage temperature range, and plan transit to avoid long periods in hot containers.
- Store on pallets off the floor, out of sunlight, with packs closed after use.
- Use stock first in, first out, and record the date each pack is opened.
- Test strength on arrival and again before using old stock, against your sealed standard.
- Do not order far more than you can use within the stated shelf life just to reach a lower unit cost.
Next step
We check manufacturing dates and packing before loading and have lots tested if there is doubt. To set this up, book a free sourcing review.