Picking the perfect colour
is one thing. Ensuring
consistency batch-to-
batch is quite a science.
Everyone sees colour
differently.
Black masterbatch is good for electro-static
conductibility, durability and exposure
to extreme weather. That’s why black is
used in a lot of functional outdoor plastic
applications, such as construction pipes,
as it is stronger and lighter than coloured
equivalents.
Performance enhancing additives are often
added to both black and white masterbatch
COLOUR MATCHING
Out of all the product types, colour masterbatch is experiencing heavy global demand.
Picking the perfect colour is one thing.
Ensuring consistency batch-to-batch is quite
a science. Everyone sees colour differently.
While Newton divided the spectrum into
seven named base colours - red, orange,
yellow, green, blue, indigo and violet,
according to psychophysicists we see tens of
millions of different hues and shades. Given
this, the human eye cannot be relied upon to
match samples accurately.
Once a specific masterbatch has been
created, specific formulation details,
including colour pigments, raw material
ratios, notes and directions are held on a
recipe card. A moulder can call up these
instructions at any time to ensure production
consistency.
for the base polymer. The more plastic is
reprocessed, the greater the molecular
structure changes. This loss of chemical
properties affects the composition and
therefore is likely to affect the compatibility of
all the ingredients within a blend.
Aesthetics aside, understanding the
environment in which the end component
will be used is critical. For example,
components exposed to direct sunlight
will need to use a specific masterbatch to
prevent discolouration. The chemistry of
some colour pigments may be incompatible
with the chemistry of some base polymers.
Additionally, other agents, such as fillers,
could impact the fusion.
One thing is certain, masterbatch has
become integral to modern day plastic
processing. Out of all the product types,
colour masterbatch is experiencing heavy
global demand. This robust growth can be
attributed to brand differentiation trends in
packaging, FMCG, furniture, construction,
agriculture and aerospace. Likewise, black
and white mastermatch is being extensively
utilised by automotive manufacturers for
lighweighting and to improve fuel efficiency.
Just like a paint swatch, new innovations
emerge on the market all the time. To trial a
different pigment or plastic effect, contact
us for advice on what’s new and how a new
formulation might impact processing stability.
Should a recipe card be unavailable, physical
samples can also be matched using a light
box or spectrophotometer.
Homogenisation of a blend, including
the dispersion of the masterbatch during
dosing, plays a big role in minimising colour
and product performance variations. Most
recipes detail the percentage by weight of
masterbatch to be applied. Yet, discrepancies
can occur. Changing the host polymer or
switching suppliers is typically when this
might happen. For this reason, moulders tend
to stick with the same supplier.
As with all plastic processing, stability is
essential. Thermal resistance and durability
need to be factored in. It’s precisely for this
reason why most processors avoid using a
high percentage of recycled plastic mixes
Thomas Catinat, operations manager at Broanmain Plastic.
For further information, please visit www.broanmainplastics.co.uk
Issue 44 PECM
83