C3.4.2

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C3.4.2 Paints, dyes and pigments
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Paints, dyes and pigments

• describe the uses of transition metals and their
  compounds in pigments and dyes

• describe the aspects of safety, sustainability
  and effects on the environment of pigments and
  dyes

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Paints, dyes and pigments
Many transition metal compounds are coloured and
soluble in water
However, not all are soluble and so dont form
solutions
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Paints, dyes and pigments
Soluble transition metal compounds that are
coloured can be used as...
DYES
Insoluble transition metal compounds that are
coloured can be used as...
PIMENTS
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Paints, dyes and pigments
The fabric that is boiled with a solution of the
dye.
The dye makes chemical bonds with the fabric.
Sometimes strong bonds are not made and another
chemical is added to make them bond this
compound is called a mordant.
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Paints, dyes and pigments
The dyes were obtained from either animal,
vegetable or mineral origins, with no or very
little processing.
Archaeological evidence shows that, particularly
in India and the Middle East, dyeing has been
carried out for over 5000 years.
The greatest source of dyes has been from the
plant kingdom, notably roots, berries, bark,
leaves and wood.
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Paints, dyes and pigments
The greatest source of dyes has been from the
plant kingdom, notably roots, berries, bark,
leaves and wood.
e.g. woad used by Ancient British tribes
e.g. henna a traditional dye
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Paints, dyes and pigments
Natural dyes tend to be limited in their range.
In the 19th century a compound called aniline was
found to be a source of brightly coloured dyes.
The source of the aniline was coal and is now oil.
These artificial dyes need far more processing in
their manufacture.
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Paints, dyes and pigments
Spodden Valley, Rochdale - exposed waste has
been photographed at Greenbooth in adjoining
woodland. The bright blue contamination appears
to be dyeing waste.
Last nights meeting heard of the types of
cancer-causing chemicals associated with sites
once involved in industrial bleaching, dyeing
work.
23.11.2005
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Transition metals
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Paints, dyes and pigments