A Non-Science Technical Guide
A non-science guide to understanding how plastisol screen printing ink works.
Having an understanding of how screen printing plastisol ink works helps in achieving a great looking screen print. This guide to plastisol ink formulation is designed to provide you with a general understanding of how the ink is made, and with the chemistry behind proper curing (fusion). By understanding the basic components and how heat cures, or dries, plastisol ink, you will get a creamier ink that is easier to print and a better looking final product.
The two main ingredients in plastisol ink are resin and plasticizer. Manufacturers use a bowtie mixer to combine the two in bulk. This mixture produces a plastisol “base” from which the plastisol ink you know and love is produced. Once the base is formulated, different color pigments are added to make white, black and all the colors. Plastisol ink manufacturers may use a variety of resins, plasticizers and pigments depending on the results they want to achieve. For example, some components may be low-cure, so the ink dries at only 280 degrees (like Dynamic Ink) or has special low-bleed properties to stop dye-migration for polyester printing.
Once you have the plastisol ink on the shirt, you will want to know the different stages it goes through before drying. When plastisol ink is exposed to heat and reaches approximately 115 degrees fahrenheit, the ink suddenly liquifies. For a brief moment, this liquid slowly turns into a solid until it reaches an equilibrium between the two states. This typically occurs when a printed shirt has been under your spot cure unit briefly.
As your shirt sits under your flash unit, it heats up past 135 degrees and the ink is neither viscous nor fused. It turns into a gel, yet it cannot be damaged and will not transfer to the following screens during the press run. This stage is important if you ever wondered why you are getting “pick up” when printing multiple colors as you might need to flash your shirt for a little longer to achieve the proper temperature.
For the ink to fully cure, it should pass through a conveyor dryer. Here, the remaining liquid absorbs into the solid of the print. This part of the process can occur instantaneously or gradually, depending on how powerfully heat is applied. You want the curing to happen as rapidly as possible without scorching your garment. While standard plastisol cures at 320 degrees and low-cure inks will dry around 280, a number of other factors can affect curing time, such as, the material of the shirt, how thick the ink is, and how many shirts are inside the heat chamber.
Learn about Properly Curing Plastisol Ink on Your GarmentsNow that you have a basic understanding of plastisol ink components and curing, you will hopefully be able to produce better screen printing t-shirts.
