Printing Inks Chemicals
Printing ink raw materials cover varnishes, resins, pigments, plasticizers, waxes, and solvents for offset, gravure, flexographic, and screen printing inks. Each print process demands different rheology, tack, drying mechanism, and substrate compatibility.
Frequently Asked Questions — Printing Inks Chemicals
What are the main resin types used in printing inks?
Offset inks use hard, high-tack resins: rosin-modified phenolics, alkyd varnishes, and petroleum resins for sheet-fed; mineral oil-gelled varnishes for heatset web. Gravure inks use nitrocellulose, polyurethane, or acrylic resins dissolved in fast-evaporating solvents. Flexo inks use acrylic emulsions or solventborne polyamide resins. UV inks use acrylated oligomers (epoxy acrylate, urethane acrylate) cured by radical photoinitiators.
How is tack measured and controlled in offset inks?
Tack is measured with an inkometer (Tack-O-Scope) at standardized RPM and temperature (32°C/200 RPM typical). Sheet-fed offset inks run at tack 10–18; heatset web inks at 6–12. Tack is controlled by: adjusting resin concentration, adding tack reducer (petroleum distillate, mineral oil), or using softer resins. Ink train sequence is highest tack first down to lowest to prevent back-trapping.
What additives control set-off and blocking in printing inks?
Set-off (ink transfer from printed sheet to the back of the next sheet in the pile) is controlled with hard waxes (PE, PTFE, carnauba), anti-set-off spray powder (starch, CaCO3), and fast-setting varnish vehicles. Blocking (adhesion between printed substrates under pressure/heat) is prevented with hard wax additives, slip agents, and ensuring full ink cure before rewinding. PTFE and polyamide waxes give the best combination of slip and anti-blocking.
Looking for specific raw materials for Printing Inks?
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