Guidelines for Using DigiPrime 6611

DigiPrime® is a water-based product designed for flexographic or gravure application. It is very stable in liquid form with a maximum shelf life of 12 months if stored unopened and at moderate temperatures. DigiPrime 6611 is capable of optimizing a wide variety of substrates including most films and papers.

Depending on type of substrate, DigiPrime 6611 primed surfaces may have a limited shelf life of up to 8 weeks following application and drying. Michelman recommends that shelf life be established for each substrate surface and application.

There also may be risk of yellowing depending on type of substrate, coat weight and storage conditions.

Substrate Selection Guide

• Papers
• Wide variety of films

Corona Treatment

Depending on substrate properties, corona treatment may be necessary to achieve proper wet-out and adhesion. Surface energy above 42 dynes/cm should be targeted if corona is needed. A dyne pen can be used to check the treatment level before priming is started.

Application

The coating system should be thoroughly cleaned before application by flushing the supply lines and pumps with water, cleaning out the coater pans, and then cleaning off the rollers. DigiPrime 6611 is not compatible with many solvents and other coating chemistries because its reaction with them will make them difficult to clean. If not sure about chemistry compatibility, try changing tubes, ink pan, and doctor blade, and/or contact your Michelman representative for more information.

Pump

We advise use of a peristaltic pump to avoid foaming and other irregularities.

Drying

A minimum web temperature of 50°C out of the dryer/oven is recommended for drying to obtain full adhesion of the coating to the substrate. Be sure to cool the web to less than 35°C to prevent winding or blocking in the wound roll. Poor drying may lead to blocking issues.

Storage of Liquid DigiPrime®

DigiPrime 6611 must be protected from freezing. The appearance of grit or gels in the product indicates freezing has occurred, and should not be used. Please store product containers in an environment above 5°C.

Cleaning

DigiPrime must not be allowed to dry on the anilox. Keep the coater moving, the rolls turning, and the surfaces wet. Use (hot) water to clean the rolls. Cleaners from the following suppliers are also recommended:

Coat Weight

A target coating weight of 0.8-1.2 gsm wet is recommended on most surfaces; however, if the surface is absorbent and/or textured, higher coat weights may be needed. Excessive coat weight may result in blocking in the wound roll and too low of a coat weight may cause a lack of adhesion. Determining a proper coat weight is established by experimentation. The coat weight should be verified according to the type of substrate and the primer applied.

Quality Check

Checking the Applied Coat Weight

It is recommended to monitor your use of DigiPrime over a known length and width of media.
Coat weight (gsm) x Length (m) x Width (m) = Consumption of DigiPrime (g)
Example: 1 wet gsm DigiPrime x 1000m long x 0.300m wide = 300 grams used
Gravimetric method: Checking coat weight on plain films can be achieved by measuring the weight difference. You will need an accurate balance, as the dry coat weight is very low.

Recommended Coat Weight

(aniloxes mentioned below are for flexo application)