QUANTIA SOLUTIONS May 2019
Polyester – a sustainable opportunity
Polyester was about 51% of the global fiber production in 2017 (Fabrikology) and the interesting thing is that the use of polyester continues to grow.
Why is polyester becoming so popular? Polyester is a synthetic, man-made fiber. Unlike cotton and other natural fibers, it’s more stable and guarantees availability since it’s not affected by any external factors such as the weather, plagues, etc. Currently, synthetic fibers are the most used in the market with roughly 65% of the world production versus 35% for natural fibers (TextileExchange) and polyester is the most used of all those synthetic fibers. In the textile industry it is referred to as PET, polyethylene terephthalate or commonly known as “poly” or “polyester”
There are two main types; virgin and recycled (rPET), which is created from plastic bottles recycled either in a mechanical process or chemically.
Today, the mechanical recycled process is the one mainly used in the textile and apparel industry. As the graphic illustrates, it means we take a plastic bottle, chop it, melt it down and we stride it into fiber. In parallel, there is a lot of research being done on chemically recycling polyester and in the future, we might see more possibilities for recycled material to go into different fabrics.
Polyester therefore is a sustainable fiber since it helps keep bottles and plastic out of the landfills and oceans. In Spain most of the recycled polyester comes from mechanical recycling of ocean plastic. Studies also show that the amount of energy needed to make rPET is far less than what is needed to make virgin polyester. Another factor to consider when selecting polyester over other type of fibers, like cotton for instance, is that it doesn´t require the use of pesticides.
Sustainable fashion is a term we are getting used to with consumers ecological awareness gaining ground. Sportswear accounts for the most part of the attire that´s created with polyester fiber. “Athleisure”, sportwear used when not doing sports, but for leisure or as a fashion statement, is also made with polyester. Another common characteristic for both these types of attire is personalization.
Let´s take a look at the current printing technologies and how to meet the demands of printing on polyester:
Heat transfer also known as Vinyl/film transfers: It is best for name and number prints with fine cut edges. It provides high quality embellishments, enhances abrasion resistance and durability and prevents dye migration (1). However, it requires a long process with multiple steps and it is labor intensive. For example, you have to remove the negative space from the letters manually – a very tedious and time-consuming process. When using this method, the compromise is on productivity and the limitations on design it presents.
Screen Printing: It is best for vector designs with solid color coverage and printing large quantity runs. It offers many solutions for printing on polyester, providing low migration of inks, capillary print (2) and utilizing a blocker under base (3) Screen printing requires expertise to reach high quality. It is not suitable for short runs because it is too expensive and time consuming. It involves the additional cost of screens, colors, setup time and blocker. The compromise when using screen printing is cost, level of expertise needed as well as the limitation on length of print runs – it is not suitable for long runs.
Sublimation: It is best for complex designs on white polyester. It offers high quality vivid bright prints but only on white polyester. Printing on dark color polyester fabrics is not possible with sublimation printing. In fact, that limits the type of garment and variations that can be printing using this method.
eTransfers or digital printing: New digital printing technology, Neo Poly technology (Kornit) recently introduced in the market, meets all current polyester printing challenges:
– Offers no limitations on run length at economic costs allowing mass customization for every size print shop that can now offer on-demand and web-to-print customized products
– Prints on a variety of polyester fabrics, including woven, knits, with poly blends (Poly-lycra, Poly-cotton) and different fabric textures.
– Prevents dye migration
– Provides fast productivity with barely any manual intervention
– Enables cost-efficient single-step process for polyester printing, even in dark color fabrics.
– Easily prints vector and photo-realistic designs making it much more versatile.
– Uses sustainable water-based ink and no harmful substances.
High-quality digital printing on polyester is now a reality. For instance, it meets the sports industry’s durability standards and preserves the fabric properties which opens a great market opportunity.
“There are no compromises with digital printing; you can have it all!” – says Ronen Zioni, General Manager at Quantia Solutions (4). “We are committed to the transformation started in polyester printing, what that implies for the textile industry and its sustainable impact,” Ronen concludes. ▪
(1) Ink migration – Dye migration occurs when dye from polyester fabric bleeds into the ink that is screen-printed on the garment. An example of this is white ink that turns pink after having been printed on a red polyester t-shirt (ShritSpace)
(2) Capillary print –degree of an ink’s ability to penetrate into a surface. In fabric printing Some types of stencils used in screen printing are applied to the screen fabric by means of capillary film. Capillary film refers to a pre-sensitized film used for screen printing stencils that is applied while wet to the screen fabric prior to exposure and development and adheres to the fabric. (PrintWiki)
(3) Blocker under base – white layer used as a base to enable bright colors on screen printing.
(4) Quantia Solutions is the official distributer of leading digital printing equipment for the textile industry and polyester printing in Spain.