Question 1

What are the main ink systems used in flexible packaging?

Accepted Answer

Solventborne nitrocellulose/polyurethane inks dominate flexible packaging gravure and flexo printing. They offer fast drying, excellent adhesion to OPP, PET, and BOPP films, and good lamination bond strength. Waterborne inks are growing for sustainability reasons but require careful substrate treatment. UV-curable inks are used in label printing for energy efficiency and instant cure.

Question 2

How are low-migration inks formulated for food packaging?

Accepted Answer

Low-migration ink formulations use large-molecule photoinitiators (for UV systems), polymeric binders with low diffusivity, and restricted substance lists compliant with Swiss Ordinance 817.023.21 and EuPIA guidelines. Migration testing per EN 1186 or OML/SML testing under food simulant conditions is required. Ink suppliers provide migration test data for compliance verification.

Question 3

Why do packaging inks need lamination bond strength additives?

Accepted Answer

After printing, flexible packaging films are typically laminated to a sealant layer with polyurethane or solvent-free adhesives. The ink layer sits in the laminate bond line and must not cause delamination. Adhesion promoters, properly cured binders, and residual solvent control (< 5 mg/m²) are critical. Polyurethane-based inks form chemical bonds with PU laminating adhesives for superior bond strength.

Packaging Inks Chemicals

Bronze Powder (Copper-Zinc Gold Powder)

Colour-Shift Pearl Pigment Purple-to-Green

Fluorescent Green Pigment FG-4

Fluorescent Red Pigment FR-5

Fluorescent Yellow Pigment FY-7

High-MW Polymeric Photoinitiator Speedcure 7010 Type

Iron Blue PB 27 (Milori Blue / Prussian Blue)

Pearl Pigment Interference Blue (TiO₂-Mica)

Pearl Pigment Interference Gold (TiO₂-Mica 60 µm)

Pearl Pigment Silver White Mica (TiO₂-Coated Mica)

Pigment Blue 15:4 (Phthalocyanine Blue Alpha)

Pigment Blue 15:6 (Phthalocyanine Blue Epsilon)

Pigment Orange 36 (Benzimidazolone Orange)

Pigment Orange 61 (Isoindoline Orange)

Pigment Red 166 (Diarylide Scarlet)

Pigment Red 207 (Quinacridone Scarlet)

Pigment Red 208 (Benzimidazolone Carmine)

Pigment Violet 37 (Dioxazine Violet)

Pigment Yellow 109 (Isoindoline Yellow)

Pigment Yellow 110 (Isoindoline Yellow Reddish)

Pigment Yellow 168 (Benzimidazolone Yellow)

Pigment Yellow 180 (Benzimidazolone Yellow HR)

Thermochromic Pigment TC-28 Blue

Thermochromic Pigment TC-45 Red

Frequently Asked Questions — Packaging Inks Chemicals

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