In the world of digital printing, direct-to-film (DTF) printing on textiles is a relative newcomer. While it’s still in early stages, DTF printing is growing rapidly. By 2030, DTF equipment is expected to be printing more than 10 billion prints1. Over the past few years, output has gone from almost zero to billions of prints.
The growth in DTF printing is driven by multiple factors, such as higher demand for customized and on-demand apparel, the ability to print on light and dark garments and many types of fabric, increased adoption of advanced printing technologies, and more business awareness of DTF printing’s cost-effectiveness and versatility.
What Is DTF Printing?
At a high level, DTF printing involves a design being printed onto a special PET transfer film using the CMYK color model and water-based inks. A layer of white ink is added on the backing of the print to ensure the design stands out, even on dark colors. The ink on the film is then coated with a special adhesive powder before the design is transferred onto the fabric using a heat press. As the adhesive powder melts, the design is released from the film and transferred to the apparel item, and the film is then peeled away. The adhesive powder used in DTF ensures a durable print that resists cracking, peeling, and fading, even after multiple washes.
The ink doesn't soak in because it's pressed on top of the item, which means it's an excellent method for printing photos, colorful designs, graphics and fine art. DTF can accommodate more intricate designs than other transfer printing methods.
DTF printing provides a cost-effective and efficient solution for customized and on-demand apparel, enabling vibrant, high-quality prints on a variety of fabrics with little setup time. It is an affordable technology for start-ups and newer companies in the garment decoration business and it also complements existing technologies, like direct-to-garment (DTG) printing. Unlike DTG printing, DTF doesn't require pre- or post-treatment of the apparel item because the adhesive powder does most of the heavy lifting. DTG also is best suited for cotton or other natural fabrics, whereas DTF printing can be done on any number of fabrics-polyester, cotton, fleece, nylon and more.
As DTF printing on textiles continues to grow rapidly, ink formulators will be looking for ways to lower ink consumption to keep the process cost effective, expand the color gamut, enhance wash and light fastness, and speed up curing times.
Ink Chemistry and Design
The ink chemistry and design plays an important role in meeting DTF printing needs today and positioning it for continued growth. The chemistry and design need to provide high-quality, reliable, stable and compliant solutions that work across a range of materials and conditions. Highly stable pigment dispersions are a very important component of the ink formulation to enable high-speed, uninterrupted inkjet printing. Pigment dispersions are designed to maintain printhead life and enable printer uptime to keep ink jetting on long runs without blocked nozzles.
The binder in the ink system also plays an important role when it comes to stretchability. The binder must have good elongation so the printed ink can stretch and flex along with the fabric without cracking or peeling.
High-Stability Dispersions
Diamond Dispersions™ HSD pigment dispersion technology from Lubrizol uses proprietary, irreversible dispersant anchoring chemistry to 'lock' the dispersant to the pigment surface. These HSD dispersions enable the formulation of inks for high-speed DTF printing applications, delivering exceptional ink stability, print performance, vivid colors and sharp details, and color fastness properties.
HSD technology works by creating a dispersion that is more stable to changes in solvent polarity and allows for more formulating latitude in the ink formulation. These dispersions also help to eliminate jetting problems and blocked nozzles to provide excellent print reliability, printhead lifetime and open time, while limiting printer downtime.
Jetting Reliability
Real-world application and testing demonstrate enhanced stability. In a jetting reliability test using a Kyocera KJ4B printhead with a jetting frequency of 30,000 drops per second, inks using HSD technology perform significantly better than those using a conventional dispersion regarding the percent nozzle drop out after 30 minutes of continuous jetting.
A Range of Colors
HSD pigment dispersions are offered in the standard four color CMYK set, as well as a range of spot colors, OGV B & R giving formulators the opportunity to develop ink sets with a wide color gamut.
Understanding the importance of the white ink in DTF printing, Lubrizol is currently developing a white dispersion offering with good opacity, good re-dispersability and low settling properties.
Future Sustainability
The PET film used in DTF printing can theoretically be recycled, but it's questionable how much actually does get recycled. Moving to a paper-based substrate from PET film would help make DTF printing more environmentally friendly. Lubrizol offers a number of resins and polymers used in papermaking that are re-pulpable and recyclable. Lubrizol also offers additional additives that could be used in release coatings in the receptive layer.
Based on extensive experience in analog package printing, Lubrizol offers a wide range of specialty chemicals and solutions designed to enhance the performance, durability and sustainability of digital ink systems. Lubrizol dispersions and resin technology have proven to work well together in real-world applications. Lubrizol offers binders under the Lubrijet™ trade name that are ideal for DTF printing applications with high elongation and elastomeric properties.
As the direct-to-film printing market continues to grow because of its cost-effective, quality output on a variety of materials, Lubrizol will continue to develop products that meet the ever-changing and demanding requirements of the dynamic digital inks market.
Contact us to learn more about how our innovations are meeting new challenges in water-based digital printing.
1 Joseph Link, Senior Editor – Digital Textiles Lead, WTiN “Unveiling market insights: tracking the growth of DTF printing”
