DigiGuard® Plus



DigiGuard® Plus strengtheners enhance HP-validated UV OPVs’ performance in combination with Michelman’s DigiPrime® priming solutions. This allows press owners to increase addressable market size, better serve high-performance label markets, and produce more with HP Indigo digital label presses.

Grow Your Business More Sustainably

  • Maximize utillization of current investment without investing in additional products or finishing equipment.
  • Replace cumbersome lamination process.
  • Increase HP Indigo press utilization with opportunities to move jobs from UV flexo / UV inkjet equipment.
  • Improve ease of use by using off-the-shelf UV varnishes and adding strengtheners.

Enter New Markets

Expand into high-performance label markets such as personal care & cosmetics, household cleaners, automotive oils & fluids, wine & beer bottles, and industrial & electronic equipment. Choose the precise strengthener, primer, varnish, and substrate to match the needed application.


  • Filmic: PETP, BOPP, PE, PS, PA, vinyl, top coated
  • Paper: uncoated, laid, coated, synthetic


  • DigiPrime® 680
  • DigiPrime® 040, 050, 060
  • Other HP Indigo approved primers from Michelman


  • UV, cannot be solvent or water based
OR MECHANICAL RESISTANCE WATER RESISTANCE WATER RESISTANCE CHEMICAL RESISTANCE CHEMICAL RESISTANCE THERMAL RESISTANCE DigiGuard® Plus 920 & 921 can be combined to provide mechanical, water, & chemical resistance. DigiGuard® Plus 902 cannot be combined with 920 or 921. DigiGuard® Plus 920 DigiGuard® Plus 921 DigiGuard® Plus 902

How We Tested Resistance

Water Testing

Eight hours submersed in room temperature water followed by peeling test with 3M 810 tape and a 2kg roller.

Chemical Testing

Two hours submerged in different chemicals followed by peeling test with 3M 810 tape and a 2kg roller.

Thermal Testing

Iced water for eight hours, hot water (90°C) for 30 minutes, followed by peeling test with 3M 810 tape and a 2kg roller.

Mechanical Testing

Bottle-to-bottle (abrasion resistance)
ASTM D4060-07 (abrasion resistance)
ASTM D5264-98 (Sutherland® Rub Test)
FINAT FTM29 (scratch resistance)

ProductWater ResistanceChemical ResistanceThermal ResistanceMechanical ResistanceOverprintability
(with 5% Additive)
DigiGuard® Plus 902n/a
DigiGuard® Plus 920n/an/an/a*
DigiGuard® Plus 921n/an/a*
Strong performance    Moderate Performance
* thermal transfer, inkjet, laser, foiling

DigiGuard® Plus 920 & DigiGuard® Plus 921 can be used in combination to provide mechanical, water, and chemical resistance.

How It Works

Ink-Varnish Interface Ink-Primer Interface Crosslinking of all layers is essential. Ink Michelman Primer Substrate UV Varnish + Strengthener

The primer, ink, and UV varnish layers must interlink to achieve the required performance. HP Indigo ElectroInk permits chemical crosslinking between it and the primer and varnish layers, which allows the strengtheners to provide the needed resistance. Additionally, the strengtheners have been successfully tested on HP Indigo-approved DigiPrime® 680. We recommend testing DigiPrime® 040, 050, and 060, and other HP Indigo-approved in-line primers to confirm performance outcomes.