Dyestuffs

Shipped as a powder, liquid or paste, packed in drums, barrels with inner paper bags or multi-ply bags.
Liable to leakage from containers. Some dyestuffs deteriorate if in contact with air. Dyestuffs fall into many different chemical classifications, but they can be split primarily into products soluble and insoluble in water. In the case of soluble dyestuffs any wetting may cause actual loss of dyestuff by leaching the material out of the package. The remaining colour may or may not have undergone some chemical deterioration with a permanent loss in value, or it may merely have changed physically and may be capable of reconstruction by drying and grinding, with comparatively small loss in value.
After becoming damp, insoluble dyestuffs can, in general, be reconstituted by a dyestuff maker, often with relatively small loss in value. Dry pigments, if allowed to become damp or wet, may suffer much greater loss in value than dyestuffs; they would certainly require to be re-treated by a manufacturer.
Neither insoluble dyestuffs nor pigments in the form of aqueous pastes should be allowed to dry out, even partially, and if for any reason drying has taken place they require re-treatment by a manufacturer, and there may be considerable loss. If the pastes are allowed to become frozen, re-treatment may again be necessary and, once again, the loss may be considerable, although in both cases it is sometimes possible to recover the greater part of the value of the material at the expense of the re-treatment and some physical loss. Contamination of any sort may result in loss of value and will probably necessitate re-treatment. Certain dyestuffs and pigments decompose when heated. In general, no adverse effect is likely below 50-60°C. A number of products melt under the influence of heat, with or without decomposition; if there is no decomposition the material can probably be re-treated, by grinding by the manufacturer, without serious loss. If even partial decomposition has taken place, the products may be a total loss.