Coatings for Printing-Grade Aluminum Foil

Acrylic Coating

Acrylic coating is the most widely used surface coating for printing-grade aluminum foil. It forms a dense, transparent protective film on the aluminum foil surface after curing.

Excellent ink adhesion, compatible with solvent-based ink, UV ink, water-based ink, offset, gravure, flexo and digital printing. Effectively avoid ink peeling, blistering and poor color retention.

Outstanding weather resistance, anti-yellowing, resistant to oxidation, acid and alkali erosion; the printed pattern will not fade or discolor during long-term storage.

High surface gloss and uniform flatness, which can restore high-definition printing details, suitable for high-end color packaging, wine labels, cosmetic packaging and pharmaceutical PTP foil.

Good corona resistance, no coating damage after corona treatment to further enhance printing fastness.

Not suitable for heat sealing. Acrylic coating cannot melt under conventional heating conditions, so it is only used as a printing base coat rather than a sealing layer.

Polyester Coating

Polyester coating has higher molecular density and stronger tensile property than acrylic coating, belonging to high-performance industrial printing coating.

Superb heat resistance, can withstand high-speed printing, high-temperature drying and post-processing without coating softening, wrinkling or peeling.

Strong solvent resistance, not easy to be corroded by strong solvent ink, ideal for gravure high-speed large-volume printing.

High mechanical strength, scratch-resistant, friction-resistant, effectively protecting the printed surface from abrasion during slitting, rewinding and packaging processing.

Low surface tension fluctuation, stable printing effect in high and low temperature environments.

Industrial decorative printing, electronic label aluminum foil, high-temperature resistant packaging printing, food high-temperature baking outer packaging foil.

The cost is higher than acrylic coating; the ink wettability is slightly weaker than acrylic, which puts forward higher requirements on ink formula. It also cannot be used for heat sealing.

Heat-Seal Coating

Heat-seal coating is a functional thermoplastic coating, the only one among the three coatings that can realize heat sealing. It is usually coated on one side or both sides of aluminum foil, used for printing + sealing integrated packaging.

Under a certain temperature, pressure and sealing time, the heat-seal coating melts and adheres tightly with the contact surface (plastic film, PVC, cardboard, another layer of aluminum foil), and bonds firmly after cooling.

Realize printing and heat sealing on the same aluminum foil substrate; the printed side can use acrylic bottom coating, and the other side is coated with heat-seal glue for sealing.

Good barrier performance, after heat sealing, it can block water vapor, oxygen, grease, prolong the shelf life of food, medicine and daily chemical products.

Good flexibility, will not crack when the packaging is folded, suitable for blister packaging, candy twist packaging, food sealing cover foil.

Single-side heat-seal coated foil: one side for printing, the other side for sealing, most commonly used for PTP pharmaceutical foil, food lidding foil.

Double-side heat-seal coated foil: both sides can be sealed, suitable for special composite packaging.

Heat-seal coating has poor scratch resistance and solvent resistance; high-temperature printing drying parameters need to be strictly controlled to prevent pre-melting of the coating and cause sticking during rolling. Most heat-seal layers cannot be directly printed, so it needs to be matched with acrylic printing primer.

Summary Table