By Cassandra Balentine
Print providers have many choices for printing to textiles. Decisions involve the print process, pretreatment, fabrics, finishes, and inks to use. These selections should be carefully made based on the requirements of the final product in terms of feel, durability, and washability.
When it comes to performance wear, polyester is the gold standard. Luckily there are many types that are easily printed onto, including polyester knit, lycra, and mesh. Nylon is popular for high-end swimwear and activewear.
“Synthetic fabrics, like polyester, are hydrophobic, which means that they naturally resist water penetration. The last thing an athlete needs is a soaked and drenched fabric weighing them down during competition,” says Lily Hunter, senior product manager, Roland DGA Corporation.
“Polyester is the preferred fabric when it comes to athletic wear, but under polyester there are many variants and options,” agrees Sharon Donovich, senior customer marketing manager, Kornit Digital. “Specifically, for athletic wear, it can be 100 percent polyester or blends with four-way stretch. For athleisure, brushed poly is popular as it has the look and feel of cotton with the moisture wicking properties of poly and high fibrillation.”
“These advanced fabrics are not like the uncomfortable—and unsightly—polyester leisure suits of olden days,” quips Hunter. “They are extremely lightweight, and they have moisture-wicking features, making them ideal for many athletes.”
In addition to the fabric selection itself, a variety of finishes are available to enhance its properties.
“Polyesters for activewear are commonly used with functional fabric finishes to improve the performance of the textile,” notes Victoria Nelson Harris, senior textile segment specialist, Mimaki USA, Inc. These include wicking finishes that allow sweat and moisture to move through and evaporate out of the fabric; others are temperature regulating, anti-shrinkage, and antimicrobial finishes.
These fabric finishes can be applied at the yarn stage and then knitted or woven into the final fabric, or the textile can be knitted or woven first and then coated with the performance finish, which is typically completed with a padding coating machine, explains Nelson Harris.
There are also different types of weaves that can be utilized for better performance and fit. “Things can be done to the polyester fibers to enhance softness and a better feel. For instance, spun polyester is processed to enhance the fabric’s softness,” shares Hunter.
Randy Anderson, product marketing manager, Mutoh America, Inc., adds that most of these activewear fabrics are blended with spandex, lycra, or other fabrics to add stretchability, often utilizing wicking technology for cooling.
The sports industry has high requirements and standards for clothing, including durability/lightfastness, perspiration, wash, and rub resistance, in addition to fabric properties like water permeability and air flow, as well as elasticity. “Typically, these features are part of the original fabric selection, but may also involve fabric coatings,” offers Donovich.
To ensure fabrics and fabric finishes act as intended, it is essential to properly match materials, inks, coatings, as well as printing and finishing processes.
Polyesters for activewear are commonly printed with the dye-sublimation (dye-sub) transfer process, which does not interfere with the textile’s finish, explains Nelson Harris. However, she says when printing with direct sublimation, the textile requires the fabric to be coated to create an ink acceptance layer. On certain coatings, such as an antimicrobial finish, the coating would cover up and may decrease the efficiency of a performance finish.
“As with anything, it is important to do your due diligence when testing prints, conducting wash tests, etc. I’m certain that fabric manufacturers make it a priority to ensure that their printable fabrics are compatible with various decoration methods, from screen to digital printing,” comments Hunter.
In lieu of critical testing, Anderson suggests following the recommendations of the coating to provide you with a proper surface for coating and printing.
Activewear Printing Methods
Many performance wear fabrics are printed using a dye-sub process, where the ink penetrates and dyes the fabric.
Nelson Harris says dye-sub transfer is the most common method for printing activewear, due to its ease of process and excellent wash and rub fastness. She recommends high- and low-energy direct dye-sub for higher end sportswear or swim products, where it is undesirable for the white of the fabric to show through when the garment is stretched on the body.
“Utilizing higher energy, direct dye-sub inks increases the resistance to UV light versus low-energy sublimation inks. The direct sublimation process requires the fabric to be coated, either steamed or undergoing dry heat ink fixation, and then a wash process,” she continues.
When considering inks, she points out that nylon fabric printed with acid inks are well suited for high-end swim and activewear. “Acid inks have excellent chlorine resistance and wash fastness, in combination with nylon’s inherent high-performance strength and durability attributes, such as low moisture absorbency, high drying time, and high abrasion resistance makes for an ideal application for the sportswear market,” comments Nelson Harris.
Acid inks require the fabric to be coated, then printed, steamed, and post-process washed. She explains that due to the steam process enabling a chemical reaction between the acid ink molecules, pre-coating, and textile, the inks penetrate the fabric and create ionic bonds. “This makes for a fabric with excellent ink penetration and color development.”
Anderson says polyester athletic wear is well suited for dye-sub since no special equipment is needed to run stretch fabrics and only heat/pressure is needed for sublimation on polyester. “Nylon is more involved in that it needs pretreatment, direct printing, steaming, and then post-processing wash and dry before it is usable.”
Hunter adds that the dye-sub processes ensure outstanding color and vibrancy, as well as superior rub resistance. “Dye-sub fabrics also have excellent hand; there is no ink sitting on top of the fabric.”
Donovich admits there are few techniques for printing to textiles suited for performance wear, and she believes they all require compromising on at least one key element. “The vinyl process is long and labor intensive, so we compromise on productivity and design capabilities. Due to the use of plotter, we can’t use semi-transparency in the design. Dye-sub is applied mainly to white polyester, so we compromise on application variety.“
When Kornit developed its NeoPoly technology, Donovich says the company wanted to eliminate such compromises. The technology enables broad application variety and can print name and number designs with fine-cut edges, like vinyl. In addition, the printing of vector designs with solid color coverage, like screen printing, is possible. NeoPoly technology can also print complex designs with vivid colors on white polyester. “But we can do more. The technology can print photorealistic designs and semi-transparency. There are no design limits, and no limits on polyester color or type,” she notes.
Every element of the printing process has an effect on the final product. Inks play an important role.
Nelson Harris believes the end garment to be produced influences the fabric, finish, and ink used. It is essential to start with the type of offering and market your product is going to be in and from here determine which attributes are non-negotiable. “This will inform what fabric, finish, and ink technology are used.”
In Anderson’s opinion, the performance materials, especially for high-profile competition settings like the Olympics, determine the ink and print processes for a material. “You don’t want to do anything to fabric that would negatively affect its performance capabilities,” he stresses.
Donovich agrees, noting the importance of selecting the right ink for specific applications. “What Kornit did is bring something to match every need. One of the most challenging factors is the dye migration that happens when you dry the print; the NeoPoly technology prevents this. We have an enhanced curing mechanism that allows physical and chemical bonding in low temperature; other technologies require high temperature for bonding or curing. The dyes from the fabric sublimate under high temperatures into the ink film layer, resulting in a discoloration of the print, creating the phenomena we call dye migration.”
Features like fabric hand and washability are important considerations to apparel production, including activewear, these properties are affected by inks.
Dye-sub transfer inks do not require a pretreatment/coating or post-process wash before the garments are cut and sewn. However, when utilizing a direct-to-fabric dye process, such as dye-sub or acid inks, says these require a post-wash process before being cut and sewn. “This is due to the fabrics being pre-coated for printing. So, any residual coating or unbonded dye—acid—will be removed and the fabric will have a softer hand or feel,” Nelson Harris.
Anderson says the nice thing about dyeing is that it adds no hand and has no washability issues. These are typical of pigment printing, which is a surface print as opposed to dye.
A lot of activewear products are printed with dye-sub processes, and therefore require heating to set the inks. Once printed, cutting and sewing is necessary to complete the apparel.
Nelson Harris breaks down the types of heating and washing methods by specific dye-sub process. For dye-sub transfer, a calendar heat process is best; low-energy direct sublimation utilizes a calendar heat press or steam, then post-process washing; high-energy direct sublimation inks are recommended to use a steam process, but also can use contact dry heat with a calendar press or a non-contact dry heat and then post-process washing; and nylon fabrics work best with acid inks and require a post-process steam and wash.
Hunter says in addition to a calendar press for the sublimation process, finishing steps typically involve some form of cutting and sewing. These steps should also be considered when determining the best inks, fabrics, and printing process for a piece of athletic wear.
“Pre-cut fabric pieces are sublimated and then sewn together, like putting together a puzzle. Another cut-and-sew method is to sublimate rolls of fabric then cut the pieces out. Sewing is the next step. Not only do you sew the pieces together, but you sew the various embellishments, such as zippers, sequins, and other decorations. Prior to packaging, the athletic wear is typically gently ironed or pressed,” she explains.
Get Moving with Digital
When producing activewear there are many considerations including the type of fabric utilized. Polyester is popular and there are many types that are easily printed onto like polyester knit, lycra, and mesh. Nylon is ideal for high-end swimwear and activewear.
In addition to the fabric, the dye-sub printing process for this specific segment of apparel must be determined, with transfer considered most used. Before production begins, this factor should be determined, along with any pre- and post-treatment, specialty fabric finishes, and, of course, the priorities of the customer. As with any project, it all comes down to specific needs.
Jan2022, Industrial Print Magazine