TEXTILES.ORG
Partnerships make for profitability in the recycling loop.
By Jon Weingartner and Paul Maddrell
There are today a number of fibers used for fabric substrates that can be considered environmentally friendly. The most common ones are bamboo, organic cotton, corn-based fibers, and recycled polyester fibers. Each of these fibers has a net positive impact on energy and resource conservation, although they have different sustainability properties when measured by cradle-to-cradle, or cradle-to-grave, criteria.
Great strides have been made by textile mills in achieving sustainable manufacturing processes, such as water and energy consumption and re-use, reduced chemical application, the use of more organic dyestuffs and chemicals, and the use of recycled packaging materials.
To determine which environmentally friendly fabric substrates would be most suitable for the fabric graphics market, these elements were researched, with a focus on the printed signage market:
- properties of each of these fibers
- type of printing equipment that is most widely used
- size of the images
- numbers of colors in the images
- average size of print runs
- state of the industry in developing sustainable green printing practices
Why dye sublimation?
Dye sublimation printing equipment is the most widely used type of printing equipment for fabric, other than vinyl, for signage applications. This type of equipment offers the most flexibility in fabric substrate choices, unlimited size of images, six-color process capability, the ability to do cost effective one-off images, and advancements in sustainable inks and paper used in the printing process.
The dye sublimation printing process requires transferring the image from paper to fabric substrates at temperatures in the 395 to 405 degrees Fahrenheit range. For this reason, polyester fabrics are the most widely used substrates. Other than fabrics made from recycled polyester fiber, all of the other environmentally friendly fiber substrates either had melt points considerably below this temperature range, or would not accept the disperse dyes used in the paper-to-fabric sublimation process. Although these fiber substrates can be printed using rotary screen equipment or pre-coated and direct printed, the inks and chemical coating systems used still require further advances in sustainable green technologies.
Recycled polyester
Recycled polyester is manu-factured from a combination of post-consumer and post-industrial waste. The post-consumer waste is derived from plastics, primarily soft drink bottles. The post-industrial waste is collected from the fiber manufacturing process. Bothof these waste streams go through a process where they are chopped, ground, melted, and converted back into chip form. This recycled chip is then extruded and textured into recycled yarn. This yarn does not have the inherent whitenessof virgin polyester nor the lot-to-lot color consistency due tothe variability of the rawmaterial stream.
Some recycled polyester fiber is manufactured in the U.S. under the Repreve® brand by Unifi Inc. All fabrics made from Repreve® recycled polyester must be tested by the company to receive a certificate of recycled content. Asian polyester fiber manufacturers are now beginning to introduce recycled polyester fibers to the U.S. market, and it is expected over the next few years that most polyester fabric constructions will be available in recycled versions.
In the last year, demand for recycled polyester substrates has exceeded production capacity, resulting in price premiums. It is expected that this supply/demand imbalance will significantly moderate in the next few years as additional capacity comes on stream and the production process becomes more efficient. Each yard of a 5 oz., 120-inch-wide fabric made from 100 percent Repeve® recycled polyester will conserve approximately 61,000 BTUs of energy, which is equivalent to one half-gallon of gasoline.
The printers
There are two different dye sublimation printers that we utilize: the HP Scitex XL Jet 3, which prints to 120 inches, and the Roland SolJet SJ-1045 EX, which prints to 108 inches. Of the several recycled fabrics available ones wefrequently use are Eco Celtic Cloth for large static banners, and Eco Trapeze for tensile fabric structures that require some stretch.
Clients for these products include a growing list of specialty retailers and trade show exhibitors. One active sporting retailer involved in a new store concept rollout immediately converted all its window banners to Eco Celtic when given the choice because it was “the right thing to do” in spite of the minor premium. This response is increasingly becoming the norm.
Closing the loop
To complete the closing of the recycling loop, producers in various steps of the process are working together. For example, Portland Color is networking with other fabric printing suppliers on the East Coast and in the Midwest to develop a sufficient critical mass of waste fabric, generated as a byproduct of the production cycle, and as post-project returned goods from retail and event clients, to be gathered at its Portland facility and then shipped to South Carolina for reprocessing.
As further proof of developing interest, that forward-thinking active sports retailer was the first client to request this service and actually be willing to pay its share of the transport costs. This is just one example of the encouraging indicators for the future that fabric producers, printers, and end-use clients are all beginning to partner on sustainability at every step of the process.