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When the print is dry, the screen inks will require fixing (fixing is
also known as curing) before it can be washed or dry cleaned.
This completes a chemical process that would have occurred
naturally over a period of time, where the polymer molecules
in the binder "cross-link" trapping the pigments in the fibres
of the material. If adequate heat is applied, then this
reaction will speed up and complete.
The heat from a very hot iron on the reverse of the printed
fabric can be enough to set the print so that the ink is wash
fast. The success of this method is determined by
the following:
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inadequate fixing - not enough heat is applied over
a long enough period
-
the binder is overloaded with pigment. Surplus
colour will come out in a wash causing discolouration of
the water and staining
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fibre content or finish on fabrics - synthetics such
as lycra and polyester and highly starched or treated
fabrics will repel the polymer molecules. Cotton
and natural fabrics
give the best results.
-
the fabric
is not 'Prepared for Dyeing' (PFD) or requires scouring to remove
any grease, oil or starch. Run a few droplets of cold water
onto the fabric. If they soak in quickly, no scour is necessary.
To remove starches, size and oils, add 5mls of Synthrapol
(a non-ionic detergent) along with 2-3 litres of water
for each 100gms of material. Stir gently over a 15 min
period, and then rinse thoroughly in warm water. It is
possible to use household detergent, but the alkaline
residue may affect the final colour or wash fastness.
The
Selectasine Screen printing system has developed over
many years and is used extensively for printing. We are often
asked about the types of surfaces on which it can be printed.
Most substrates can be printed onto using this system, but not
every substrate will be suited to this medium and the print
will not necessarily be permanent.
We would always recommend a trial print and a test wash before
selling any product on the market.
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