Pigments are coloured, finely divided solids essentially used in the colouration of materials. They are used in the colouration of plastics because they are soluble in their polymeric application medium and because they have superior fastness properties and migration resistance. A pigment is incorporated into a plastic by a dispersion process. Whilst the plastic is in its molten state, the pigment is added and after the plastic solidifies the dispersed pigment particles are retained physically within the solid polymer matrix thus providing colour.
The main reasons that pigments are incorporated into plastics include aesthetic reasons and market appeal. However they are also used to determine whether the plastic medium will be opaque or transparent or for functional demands e.g. mechanical reinforcement of the plastic or for the inhibition of polymer degradation. As well as having beneficial effects, the inclusion of pigments into plastics may occasionally produce problems such as the warping of polyolefins as a result of uncontrolled nucleation.The ability to produce the desired optical effect in the plastic product is obviously a prime requirement in the plastics industry. However the pigments must also be capable of withstanding the effects of the environment in which they are placed, both in processing and in their anticipated useful lifetime. Pigments are selected for a particular application on the basis of their technical performance but also with due regard to toxological considerations and cost.
A Current Awareness service from Rapra may be just what you need to update your knowledge with ease and accuracy without having to waste time, effort and money finding the information yourself.
If there are many people within your organisation who would benefit from this information then get in touch to talk to us about our multi-recipient bulletin.
You can also request samples of this bulletin.