Revealed: Medical Packaging Applications- A Guide to Tyvek Printing
Printing on pharmaceutical packaging styles and medical Tyvek can be done using suitable inks and standard commercial printing equipment. Due to the unique requirements for medical and pharmaceutical packaging, it is important to know that these Tyvek styles have no corona treatment or antistatic coating. Therefore, special measures have to be taken in order to obtain the best printing results. When printing on pharmaceutical packaging styles and medical Tyvek, it is advisable to first begin by testing before commencing production operations aided by the following 4 guidelines:
Printing guidelines- Flexography
The ideal technique for printing on pharmaceutical packaging styles and Tyvek medical is flexography. For optimum results, use the sheet’s smooth side- the difference between the smooth side and the rough (wire) side is minor but can be felt. Additionally, some rolls supplied by sterile packaging manufacturers are wound with the smooth side out while others may be wound differently, so ensure that you ascertain with your supplier or manufacturer beforehand. Because it is quite difficult to tell the difference between Tyvek’s two sides, a simple procedure has been developed to help users distinguish the rough side from the smooth side. Your supplier/manufacturer should equip you adequately so that you can make this determination.
Flexography- Press Conditions
Optimizing press conditions for a Tyvek printer will help prevent ink pick-off, softening of adhesives, registration issues in multi-color jobs, and sheet distortion. It is thus advisable to use chilled rods, maintain web temperatures below 79ºC (175ºF), and keep tensions below 1.3N/cm (0.75lb/in) of width before windup.
Flexography- Printing Plates
Identifying the appropriate choice of printing plate depends on the nature of the printing task(s). For ultimate performance, the best practices in general printing ought to be followed so as to optimize the pressroom’s conditions. Printing variables include but are not limited to the cushion, plate, anilox, and ink. As always, it is recommended that the printing plate be cleaned with 100% alcohol before inking in order to enhance ink transfer.
For printing type, solids, and other detail-oriented images, one should use a medium durometer plate that should be complemented with a firm or medium density cushion. Further, anilox selection should be based on volume and a line screen that prevents over-inking of the plate. Remember to check for the manufacturer’s guidelines pertaining to pH, viscosity and other transfer properties that are dependent on your resistance and ink application properties.
For images that are characterized by fine line screens and dots, a harder durometer plate is recommended. This can be complemented with a medium or soft density cushion. Again, anilox selection here ought to be based on line screen volumes that guard against over-inking the plate. Lastly, and as pointed out above, seek your manufacturer’s/supplier’s guidelines for pH, viscosity and other transfer properties that are dependent on your resistance and ink application properties.
Besides choosing the appropriate ink for your printing processes, it is important to also verify its suitability in applications where there is likely to be direct contact with the medical device. The best rub resistance and adhesion is typically provided by alcohol-based polyamide inks while adding microcrystalline wax to the aforesaid inks should reduce the offsetting. Alternatively, water-based inks make it easier to achieve high-quality results with the added benefit of complying with environmental regulations.