Silicone ink has emerged as a significant material in the printing industry due to its unique properties. It is suitable for use in both silicone rubber goods manufacturing and textile printing. This article will cover the definition, composition, characteristics, and various applications of this distinctive ink.

Definition and composition

Silicone ink is a specialized two-part ink system that utilizes liquid silicone polymer as its base along with a catalyst for curing.

Silicone is a synthetic polymer made up of siloxane, a repeating chain of silicon and oxygen atoms with organic side chains. The general chemical formula for silicones is (R₂SiO) n, with ‘R’ representing organic groups such as methyl (CH₃), ethyl, or phenyl. The ‘n’ indicates the number of repeating units in the polymer chain. Silicones have inorganic silicon-oxygen (Si-O) backbone, along with organic side groups that are attached to the silicon atoms.

To make silicone ink, the silicone polymer is mixed with a pigment, additives, and solvents. The choice of pigments and additives depends on the desired printing effect and application requirements.

Silicone ink properties

  • High flexibility: Once the ink is cured onto fabric or rubber, it can stretch and bend with the base material without cracking or peeling. This ink not only retains the elasticity of the base product but also preserves its softness after curing.
  • Heat resistance: Silicone rubber is stable even at high temperatures, and so are the inks made from silicone. Due to their ability to withstand high temperatures, these inks are excellent for printing on products that are exposed to high temperatures, such as rocket shields, cooking utensils, and even metals—this application requires the use of silicone primer to permanently bond.
  • Durability: Silicone has excellent resistance to weather elements, chemicals, acids, and abrasion.

Applications:

There are a wide range of applications for silicone ink. Below is a summary of the most common printing applications.

Textile printing: This ink is utilized for screen printing on apparel made from natural fibers and sportswear. In addition to screen printing, these inks can also be used for coating textiles, creating special effects, and specialized applications like shoelace dipping. An example of screen printing silicone ink for apparel is the SilTex inks from Boston Industrial Solutions, Inc. These inks produce soft, washable, and abrasion-resistant patterns or labels on fabric surfaces.

Silicone rubber products: Like apparel printing, these products utilize a different type of ink. Silicone rubber inks have a lower viscosity but feature high pigment ratios. These inks are commonly used in the medical equipment field and for printing on gift items, including wristbands, silicone drinkware, automotive hoses, swim caps, and more. The Natron® SE Series is the best ink for printing on rubber.

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