Resin is the main film-forming component in printing ink. It influences pigment dispersion, adhesion, drying speed, gloss, flexibility and resistance.

There is no universal resin for every ink. The right choice depends on the ink system, substrate, printing method and the conditions the printed product will face after printing.

Quick Resin Selection Guide

Ink typeCommon resin choicesMain advantagesTypical applications

Quick Resin Selection Guide

This table provides a useful starting point, but the final choice still needs to be tested in the complete ink formulation.

Water-Based Inks

Water-based inks commonly use acrylic resin, acrylic emulsion or waterborne polyurethane.

Acrylic resin is often used during pigment grinding. It helps wet the pigment, improve color development and keep the dispersion stable.

Acrylic emulsion usually acts as the main binder. Its glass transition temperature has a direct effect on the finished ink film. A higher-Tg emulsion gives better hardness and block resistance, while a lower-Tg emulsion improves film formation and flexibility.

Waterborne polyurethane is useful when the ink needs better adhesion, toughness or abrasion resistance. In many formulations, it is blended with acrylic emulsion rather than used alone.

Solvent-Based Inks

Polyurethane resin remains a common choice for flexible packaging inks because it adheres well to treated plastic films and keeps the printed layer flexible.

Acrylic resin is often selected when gloss, color retention and weather resistance are important.

Polyester resin works well on PET and metal and is suitable for applications that require better heat or solvent resistance.

For laminated packaging, the ink resin must also be compatible with the lamination adhesive. Good adhesion before lamination does not always mean good performance after lamination.

UV-Curable Inks

UV inks use reactive oligomers that cure under ultraviolet light.

Epoxy acrylate provides fast curing, high hardness and good chemical resistance. It is more suitable for rigid materials.

Polyurethane acrylate offers better flexibility and toughness, making it a useful choice for labels, films and other materials that may bend.Polyester acrylate has relatively low viscosity and good flow. It is often used where printability and curing speed are important.

In practice, UV formulations often combine more than one oligomer to balance hardness, flexibility and adhesion.

Two-Component and High-Solids Systems

Two-component polyurethane ink usually combines a hydroxyl-functional resin with an isocyanate hardener. After curing, it provides strong adhesion, good flexibility and improved chemical resistance.

Two-component epoxy systems produce a harder film and are commonly used on metal, glass and rigid industrial parts.

High-solids reactive inks may use polyurethane, epoxy or acrylate systems. Their curing mechanism, application viscosity and pot life need to be considered together.

The Substrate Matters

The same resin can perform very differently on different materials.

A printing primer may be needed when the substrate surface does not provide enough adhesion.

What Should Be Tested?

Before a resin is confirmed for production, the complete ink formulation should be checked for:

Adhesion

Drying or curing speed

Gloss

Flexibility

Block resistance

Rub and abrasion resistance

Water and chemical resistance

Storage stability

Lamination compatibility

Testing on the customer’s actual substrate gives a more reliable result than testing only on a standard laboratory panel.

Sinograce Chemical supplies water-based acrylic resins, pigment grinding resins, acrylic emulsions, waterborne polyurethane dispersions and printing primers for ink applications.

Contact: sales@sinogracechem.com