U.V. Coating | Technical specifications

UV coating can offer dramatic visual appeal and protection to your job. There are a few important steps and precautions that must be addressed before printing so the results will be what you and your client are expecting. It is our goal to have your job go through the process smoothly and without issues. The information below is critical to ensuring good results.

Stock

The material that you print on must be coated and have a smooth finish. Lightly coated and porous stocks are not suitable for U.V. coating. Cast coated sheets are not advisable due to their porosity.

Inks

The simple answer is to consult your ink supplier and let them know the job will be U.V. coated. They have the expertise to supply the correct inks and aqueous primer coatings to ensure a successful end product.

Inks should be free of waxes and silicones. Additives that migrate or boil to the top of the ink as it dries can cause adhesion issues. Maintaining a proper ink / water balance is critical to inks drying. If inks become emulsified the drying time will be greatly increased.

Inks must not contain alkali sensitive pigments such as Reflex Blue, Rhodamine Red, and Warm Red. These pigments will burn out and fade after the UV coating is applied. Sometimes many hours after the coating process.

The smaller percentages of these pigments will cause the most dramatic shifts. Your ink supplier can formulate PMS colors with pigments that will not burn out. We have no way of knowing what pigments are in your ink formulation and cannot assume liability for color shifts if the above pigments are used.

Please contact your ink supplier, if they know the job will be UV coated they will supply you with the correct ink formulation. Inks must be dry before U.V. coating. A common misconception is that aqueous coating will help speed up the processing of the job and allow the sheets to be U.V. coated sooner.

Aqueous coatings actually slow down the ink drying process and contribute to solvent retention in the inks. Always add extra time to allow for the inks to dry before UV coating. Usually 24 to 48 hours is sufficient.

Aqueous coatings

The best way to ensure good UV coating adhesion over and aqueous coating is to use a coating that is specifically made as a primer coating. Work and turn coatings are often used in place of a primer coating and many times they do perform well.

However, most work and turn coatings do contain wax that will migrate to the surface. We recommend using primer coating to ensure good adhesion. Your aqueouscoating supplier will know which coatings are compatible with offline UV coating.

Offset spray powder

Excess powder has always caused problems for UV coaters. Excess powder or the wrong type of powder will cause the UV coating to be rough and dull as the powder particle size is actually larger in diameter than the thickness of the UV coating. Use the smallest micron size possible of uncoated (untreated) powder.

Many printers that are experienced with U.V. coating will run a dust pass after printing to ensure the highest quality. If you are unsure about the effect UV coating will have on your project we encourage you to send us an ink drawdown on the stock you intend to use.

We can coat the drawdown with the specified coating and return it to you quickly.