Heat Transfer Printing

Heat transfer printing, commonly known as sublimation printing when used with polyester, involves printing a design onto special transfer paper first, then using heat and pressure to transfer that design onto fabric. For polyester substrates, the sublimation process causes disperse dyes to convert directly from solid to gas, penetrating the fiber structure without passing through a liquid phase.

The process begins with printing the design in reverse onto specially coated transfer paper using sublimation inks. The printed paper is then positioned face-down on the fabric and placed in a heat press. Under temperatures typically between 180°C and 210°C combined with pressure, the sublimation dyes vaporize and penetrate into the polyester fiber structure. As the fabric cools, the dye molecules become trapped within the fibers, creating a permanent bond. The transfer paper is removed after pressing, and no washing step is required since all the dye has transferred into the fabric.

Heat transfer printing offers several compelling advantages for appropriate applications. The process produces photo-quality prints with smooth gradients and fine detail that rival photographic reproduction. Because the dye becomes part of the fiber structure rather than sitting on the surface, prints have excellent wash fastness and durability. The process uses no water, making it environmentally favorable compared to wet printing methods. Production is quick since there is no drying or washing time required.

The technique does have specific requirements that limit its application range. Sublimation works effectively only on polyester or polyester-coated substrates because the dye requires synthetic fibers to bond with. Special sublimation inks and transfer papers are necessary. Heat press equipment capable of maintaining consistent temperature and pressure is required. Heat transfer printing excels for sportswear where durability and vibrant colors are essential, promotional items and custom apparel, flags and banners, and soft signage applications.