Inks
Inks used in screenprinting are more varied and complex than most other printing processes because of the wide range of different materials a modern screenprinter can print on. Basically, inks are made up of a carrier, which is a thick clear liquid, plus finely ground pigments for colour, and different thinners used to make the ink flow. Job number 1 for any ink is to stick to the substrate, and it follows that due to the many different materials screen printers have to print, and their different molecular make-ups, there are a large assortment of different ink TYPES, manufactured by many different manufacturers, specifically designed to bond to various plastics, papers, glass, metal, or whatever you are trying to print. Many manufacturers produce a multi-purpose ink that will work well on a range of different materials.
Manufacturers produce inks in LINES that are based on the
thinning and drying characteristics of the ingredients used in the
clear resin or binder which makes up the bulk of the ink.
Solvent-based, water-based, plastisols, and UV inks are the most common
lines, and within the lines, different TYPES of inks are produced to print on different substrates.
A COLOUR SYSTEM unique to each manufacturer is common, with
the colours having different names and code numbers, available in each
of the manufacturers' lines and types of ink.
SPECIAL FORMULATION inks, which include conductive metals,
acid resists, adhesives, or ground glass, are used when screen printing
is being used as part of an industrial process. These inks are usually
supplied by specialized manufacturers, or formulated by the user.
INK TYPES
In general, ink types and a list of their applications are provided on colourcards by manufacturers and their suppliers. The golden rule of inks is TEST if you are unsure if the ink will stick on a specific material. The best idea when dealing with a material you have not printed before is to give it to your supplier and have them test it and recommend what type of ink to use. Saves buying ink that doesn't work.
Also, every ink manufacturer and supplier is covered by a disclaimer that the ultimate responsibility lies with the user when it comes to suitability. So don't go whining when your biggest customer phones up and says the ink is falling off the decals you just printed. In most cases, plastics give the most problems. There is a world of difference between polyeurethane and polyethelene, PVC and acrylic.
Here are some common types of ink:
MULTI-PURPOSE or GENERAL-PURPOSE
- These inks will stick on lots of things, from card and paper stock to vinyls, styrenes, acrylics, and sometimes coroplast.
- Big Advantage is you don't have to carry a full range of material-specific ink types, plus different thinners and colours.
