Jan. 13, 2022
Textile applications are a key area of the digital printing industry. So why is it so hard to find the right technology? InkMall offers a beginner's guide to textile printing.
When learning about textile digital printing, beginners are often confused by the many different technologies available today. The easiest way to understand the market and the related ink technologies is to divide them by application into different sections.
✱Banner Printing
✱Soft signage
✱Roll-to-roll textile printing
✱Apparel printing
These sections do not have strict boundaries, but they do overlap and define the requirements needed for the inks and techniques used.
In many ways, digital printing of banners and flags may be considered a "predecessor" to soft signage. Since the 1990s, Pioneer has attempted to move from screen printing to digital printing for the production of flags.
For most national and corporate flags, the resolution is often not a problem; however, the durability of the logo can be problematic.
Most outdoor flags are made of polyester. Today, they are usually printed using water-based direct disperse dye inks. When coloring polyester with disperse dye inks, the result looks a bit dull at first because the color needs 170 °C to develop. This is usually used in conjunction with heat rollers built into the printer or mounted on the printer.
Direct disperse dye inks provide good through-printing, which means that both sides of the flag look colorful. Outdoor durability is typically up to 3 years. This is why direct dispersion ink technology is used in the automotive industry as well as for garden furniture.
Thermal sublimation inks are also commonly used in the production of flags and banners. They are first printed on a very thin transfer paper. During the transfer sublimation process, when the transfer paper and the polyester fabric are calendered together at 180 to 200°C, the color changes from a solid to a vapor phase without going through an intermediate liquid phase. The color is then deeply embedded in the fiber. Sublimation printing solutions are available from a variety of manufacturers.
Thermal sublimation inks produce very sharp images and can be used to create small letters for soft signage applications. Straight-through printing is much less expensive than direct disperse dye sublimation inks. The durability of sublimation printing is usually very low.
Soft signage applications involve printing signs on textiles rather than paper, banner material, self-adhesive or mesh. The most commonly used are.
✴ Dye inks
✴ Latex inks
✴ UV-curable inks.
With the exception of thermal sublimation inks, the inks used for indoor and outdoor soft signage are the same technology used for many other roll-to-roll and rigid applications and are therefore not textile specific.
Pigment inks are also popular for home décor applications. Pigment inks are also very popular in roll-to-roll digital textile printing because they can be used on a wide range of fibers. Prints made with pigment inks look duller than acid and reactive dyes. Because the color does not penetrate the surface of the fabric, but rather settles on the surface of the fiber, it sometimes lacks washability, although color fastness is usually good. For this reason, most experts recommend using pigment inks for home décor rather than everyday fashion applications.
Industrial strength roll-to-roll textile digital printing occurs primarily in the textile industry. The two main water-based liquids used there, reactive dyes for cotton, wool and nylon, and acidic inks for silk, wool or polyamide, require custom pretreatment to achieve high-quality results. Post-treatment requires steam treatment to ensure that the dye is embedded in the fiber. Several wash cycles are required to remove any excess ink.
Acid and reactive dyes provide vibrant colors, a smooth fabric feel, good washability and lightfastness, and are used primarily for fashion and high-end home décor. Inkjet inks are available for some of the company's market leading print heads.
Digital printing has been used to print shirts, hats and other apparel since the first 4C inkjet prints were offered by copy stores. In earlier years, printer output on thick heat sublimation foil was simply ironed or heat pressed onto the item.
Today, the available sublimation ink solutions for garment printing are much more complex. They still require polyester or polyester blends as substrates or polyester pre-coatings. This is why thermal sublimation inks are often used for sports fashion as well as many home décor applications such as cushions.
Sublimation inkjet printing technology works best on white gloss textiles.
Today, water-based pigment inks are widely used for apparel printing because they are suitable for most fibers on the market. They are printed directly on the item, hence the name "direct to garment" (DTG). Pigment DTG inks are available in CMYK and opaque white, and they can also be printed on dark fabrics. They usually require pre-treatment and fixing in a hot press at approximately 160 °C.
Today, there are a variety of ink technologies available to meet every digital textile printing need. However, it is important to consider that depending on the technology, pre-processing and post-processing will take a significant amount of time. The necessary pre- and post-printing steps may require additional investments that may exceed the price of the printer. Therefore, an in-depth study is highly recommended.
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