Plastic Card Printing Quality Improves with Plasma Treatment
Experiencing difficulty printing to plastic cards? Whether you’re printing to library cards or loyalty cards, they’re typically all manufactured using “non-stick” polymers such as PVC. We look at the reason why achieving good print adhesion can be so difficult and most importantly, how to overcome the issue.
Typically, plastic cards of all varieties, from library cards to loyalty cards, are manufactured using PVC; the “non-stick” nature of PVC and other polymers and composite blends often results in inks drawing back and printing inks being easily rubbed off. As a result of this, when printing plastic cards achieving strong print adhesion and strong lamination to plastic cards is a problem widely faced throughout the industry.
With engineers boasting over 40 years’ experience, the Dyne Technology team has experience with a vast range of plastic card applications from bar coding, encapsulation, DOD printing, UV printing, surface cleaning and more. Dyne Technology is proud to offer above industry standard expertise and state-of-the-art Plasma Surface Treatment solutions ensure perfect ink adhesion every time, even at high line speeds…
Achieving Good Adhesion when Printing Plastic Cards
The reason for the poor adhesion experienced when printing plastics cards is that the most commonly used material used for manufacturing plastic cards, PVC, which typically has a low surface energy of around 34-38 Dynes/cm² (mN/m).
The chart above, courtesy of Konica Minolta, illustrates the visible increase in print quality as the surface energy of the material increases. As a general rule, to achieve good adhesion when printing, the surface energy of the material must be higher than the surface tension of the ink.
Typically, inkjet ink is of a fixed surface tension and as a result, manufacturers often have to find a solution to increase the surface energy of the material being printed upon. In order to improve adhesion qualities, it is vital to undertake testing to determine the surface energy of the material and the surface tension of the ink being applied.
Dyne Technology engineers recommend a Force/Bubble Tensiometer to accurately measure the ink’s surface tension; after testing the surface tension of the ink, a Contact Angle Meter can be used to measure the surface energy of the material. Dyne Technology recommend visiting Dyne Testing for all surface measurement equipment. Once thorough testing has been undertaken, the ideal surface energy of the material relative to the surface tension of the ink can be determined to ensure consistent and reliable surface activation levels.
How does Plasma Treating improve plastic card printing quality?
Plasma Treating provides an environmentally friendly, economic, efficient and easily repeatable surface activation process, which is perfect for improving adhesion quality when printing plastic cards.
In simple terms, Plasma is a super ionised gas which can react with a wide range of materials including polymers, composite blends, metals, glass and ceramics. When atoms are subjected to a high energy, the electrons around the nucleus begin to “boil off” and the increasing temperature results in the atoms being too hot to stay contained in orbit around the nucleus. The free radicals and other particles that exist within the highly active plasma discharge can now attach to the materials surface resulting in the formation of additional polar groups; this change results in the material now having a strong chemical attraction to inks, ensuring good wetting of printing inks and strong bond strength.
This treatment not only increases the surface wettability, ensuring good spreading of the ink and strong print adhesion, but also cleans the material’s surface, removing organic contaminants as a result of ion bombardment. This makes it the perfect surface preparation technology for plastic card manufacturing as once the material has had the organic contaminants removed, it is in perfect condition to receive inks or lamination’s ensuring high quality plastic card printing.
Which Plasma Treating Technology is right for me?
Atmospheric Plasma technology is ideally suited to the high performance demands of the plastic card industry. Ideal for high line speeds, our easily repeatable process can plasma treat up to 30,000 cards per hour and offers true flexibility to fit within your manufacturing process.
Dyne Technology’s exclusive Atmospheric Plasma offering is not only the most efficient, economic and intelligent offering yet, but it is also over 50% smaller than traditional Atmospheric Plasma systems saving all important floor space.
Although small in size, Dyne Technology’s Atmospheric Plasma is equipped with the latest technology which is guaranteed to keep up with the demands of the plastic card industry. Boasting plug and play features with fast ramp up times, the unit is easily integrated into new and existing production facilities. High technology boost mode gives you the flexibility to boost power output by 50%, perfect for the high speed production required for plastic card printing.
Give the Dyne Technology engineers a call on +44(0) 1543 411 460 or send us an email and we’ll be happy to have a chat to better understand your problem.