 Polyscreen PS is a two-pack screen ink combining outstanding resistance to many chemicals and solvents with excellent adhesion to an extensive range of ‘difficult’ surfaces.
Mixing
Polyscreen PS inks are
supplied in two parts (ink and catalyst). The tin containing the ink
has sufficient space to take the catalyst which must be added to cure
the system. Before printing, estimate the amount of ink required for a
day’s work and thoroughly mix the ink and catalyst together in the following ratios:
Polyscreen Inks: 5 parts by weight
Polyscreen Catalyst: 1 part by weight
Polyscreen Varnish: 3 parts by weight
Polyscreen Catalyst: 1 part by weight
Polyscreen Matt Catalyst is available to obtain finishes ranging from satin to matt by varying the mixing ratio from 5:1 for a satin finish to 1:1 for a matt finish. Metallic Gold and Silver shades may be produced by mixing, by weight, 3 parts of Polyscreen Varnish with either 1 part of MP461 Rich Pale Gold Powder - Superfine or 1 part of MP467 Silver Paste - Superfine plus 1 part of Polyscreen Catalyst. See Information Sheet ‘Universal Tinters, Metallic Inks and Varnishes’. A non-tarnishing gold is also available on request.
Drying
Polyscreen PS dries by
a combination of solvent evaporation and a chemical reaction between
the base and catalyst. Air drying times can be as fast as half an hour
using ZV551 Thinner and Cleaner or as slow as 5 hours when using ZV574
Retarder. At room temperature, full chemical resistance and adhesion are
not developed until about 4 days after printing.
Adhesion
Polyscreen PS inks possess excellent adhesion over a wide range of
difficult metal, ceramic and plastic surfaces including: aluminium,
copper, brass, tinplate, steel and most of their alloys, ceramics,
glass, vitreous enamel, phenolics (‘Bakelite’), ureas/melamines
(‘Formica’), resin impregnated papers for laminating, acrylics
(‘Oroglas’, ‘Perspex’), flame treated polyethylene and polypropylene,
nylon and certain grades of polyester films. Polyscreen has excellent
adhesion to most stoved enamel surfaces and generally overcomes the ink
repellent effects of silicones and waxes often found in stoved enamels.
In case of difficulty, adhesion may often be enhanced by wiping the
enamel surface with good quality white spirit, ZS640 Tursub or Propanol.
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