An Overview of Textile Screen Printing Inks

Screen Printing is a very versatile print process. If there is a flat surface, It can most likely be screen printed. A major consideration for any job, is the ink system to be used for a given material, or substrate. For this blog post, we will be focusing on textile applications. With the goal being an increased understanding  and awareness of the abilities, applications, limitations, and economic factors that different ink systems provide.

Plastisol

Plastisol ink has been the staple ink for the garment printing industry for many years, so it makes good sense to start here. Plastisols are non water soluble and they must be heated to cure. Therefore they do not dry in the screen and are easy to work with on press. They are very opaque on dark garments, and are relatively simple to color match using pantone mixing systems. There are a wide variety of additives available which provide an enormous amount of flexibility. In addition, many special effects can be achieved using plastisol inks. Plastisol inks are well suited to a number of garment types and blends which make it a very versatile ink system. Its consistency and repeatability make it the go to ink for printers around the world. The ink components are generally more expensive than waterbased or discharge inks, but due to the printability and ease of use, plastisol is generally the most economical and cost effective ink for the majority of the apparel industry.

Waterbased and Discharge inks (HSA)

Waterbased inks have been growing in popularity recently, and for good reason. When printing waterbased inks, the ink is driven into the substrate, rather than sitting on top of the garment as with plastisol. Waterbased inks provide a very soft hand, after washing the garment will have very little to no hand. Waterbased ink is especially great for heavy nap fabrics such as towels where you want a soft surface. When cured properly, the ink will last for a very long time. Discharge inks are waterbased inks that utilize a ZFS (Zinc Formaldahyde Sulfoxylate) activator and work on 100% cotton fibers to remove the dye from cotton threads. For this reason, discharge is best used on dark 100% cotton garments. Testing is key when printing with WB and discharge inks, especially with blended garments. Waterbased inks are more difficult to mix, and while the ink components may cost less than plastisol, the time it takes to mix the ink, the requirement for hardened emulsions, and the on press characteristics of the ink make discharge a more expensive ink system in the majority of cases.

Silicone Ink

Of all of the ink systems, silicone ink is the newest. It was developed by Dow Corning in recent years to combat some of the limitations of plastisol when printing on 100% polyester garments. Polyester garments are heat sensitive, and they don’t like to hold on to their dye when heated. Sublimation and outgassing occurs near the cure temp of plastisol, which causes dye migration from the garment to the ink layer. For years low bleed plastisols have been employed often with less than optimal results. Silicone ink  is quickly changing the way performance apparel is printed. Pantone colors are  easily matched, dye migration is avoided, and the hand of this ink is unlike any other on the market. With more and more performance, moisture wicking, and  synthetic blended materials coming onto the market, high performance ink is required. The high cost of the raw ink components do make it one of the most expensive ink systems that we use on garments. It is a catalyzed ink, so it has a limited screen life once mixed. This is one of the reasons that small batches become uneconomical to print with this system. Mid and large print runs are quite affordable when the ink cost is spread out over a larger number of garments.

The Keys to Success

Understanding the substrate, the ink systems, and a general knowledge of the print process is a must if you want to take your garments from good to great. As with anything, there are many ways to achieve the desired outcomes. The more that is understand about inks, garments, and the screen process in general, the more you are empowered to make great decisions when creating art, choosing blanks, and determining what ink is best for you needs. In future posts, we will explore each ink system in a more in depth way.