From Bottles to Blouses: Inside Unifi’s Repreve Operation

May 25, 2023

Nestled amid rolling farmland in rural North Carolina, a massive facility looms over the fields, its gleaming silver silos and vast expanse of solar panels offering a hint as to what's happening inside. Within the walls, unmanned robotic vehicles traverse the floor, passing expanses of whirring automated machinery spinning threads in a rainbow of colors onto bobbins.

This is one of Unifi's three North Carolina facilities—located in Yadkinville, Madison and Reidsville—each focused on converting plastic bottles into Repreve yarns. Those yarns are then incorporated into products by such brands as Nike, H&M, VF, Under Armour and Levi's, among many others.

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Unifi—which was founded in 1968 as Universal Textured Yarns—didn't begin producing Repreve until 2004 after a machine malfunction resulted in fiber waste, sparking the idea of finding a use for such refuse. At first, Unifi used post-industrial waste to make Repreve, eventually transitioning to post-consumer waste in the form of plastic bottles. Since then, Unifi has focused its operation on Repreve production, converting more than 35 billion recycled bottles into yarn since its inception.

Unifi's three North Carolina facilities represent different points in the Repreve production process. The Reidsville plant handles bottle recycling and the company's package dye facility.

At the Yadkinville plant, processed bottles are extruded and spun into Repreve yarn, and the Madison operation houses multiple product lines, as well as a sock and hosiery lab.

But the first stop for a Repreve yarn is Reidsville, where 40 to 60 truckloads of plastic bottles arrive per week, with each truckload weighing around 40,000 pounds. The facility's bale yard houses around 5 million pounds of bottles with a goal of processing 1.5 million pounds per week. Of the plastic Unifi receives, 62 percent is useable, with 58 percent being clear polyethylene terephthalate (PET) plastic bottles and 4 percent colored plastic bottles.

Tightly packed bales of bottles move into sorting after being delivered, going through several rounds to separate the clear plastic from contaminants. Optical sorting machines perform the first round of separating the clear plastic from colored pieces and other materials. Once the machine finishes, workers do a manual sort, pulling anything missed on the first round. Bottles can go through an additional round of sorting if necessary.

"We don't want to discard anything at this point that could be PET," said Kerby Stone, plant manager, bottle processing, Unifi.

Any materials pulled during the sorting process—including caps and labels—are sent to an outside recycling center. Once those contaminants are removed, bottles go through a washer and then into the grinder where they are transitioned into small flakes.

Though the plastic has already been through several rounds of sorting to remove debris, the flakes undergo several more quality-control checks. One cooks the pieces at 200 degrees, which pulls out contaminants, and then it gets cooked again at 165 degrees and run through a filtering machine to remove sand, carbon and other grit.

The flakes then get poured into vats of water to assess their quality—good PET flakes sink to the bottom while inferior pieces float to the top due to bubbles inside the plastic. After that, the flakes go through one last sorter before being poured into 1,500-1,700-pound bags and sent to Unifi's Yadkinville facility.

In Yadkinville, the bags of chips are poured into massive blending silos for one last round of sorting to remove any fluctuation in the material. Then the flakes are sent to the extruder to make pellets.

At this point, Unifi adds its proprietary fiber print technology that allows the company to test for and identify Repreve fibers in yarns, fabrics or end products.

"We’ve chosen some unique components that are inert that we can test through third party entities," said Dennis Joyner, spinning site manager, Unifi's Yadkinville facility. "We have the ability to track our products at any time in the process to provide full traceability."

Unifi launched its own certification process, U-Trust, last year to ensure products actually contain Repreve fibers. And Repreve also goes through third-party certification processes such as Global Recycled Standard and Oeko-Tex.

"We focus on testing Repreve fabrics from different sources to bring further transparency and clarity," said Meredith Boyd, senior vice president, technology, innovation and sustainability, Unifi. "We feel having these certifications ensure that what you have is Repreve and it's done correctly and fairly."

Pellets then go into the extruder, which melts the plastic into a liquid, which is then quenched and spun into yarn. That yarn goes through the winder and onto bobbins, which are transported through the plant via automated guided vehicles (AGV) or laser guided vehicles (LGV)—unmanned vehicles that transport dozens of spools of yarn through the facility.

Robotics play a big role in Unifi's Yadkinville plant, where the AGVs and LGVs are joined by more than two dozen automated texturizing machines that take raw fiber yarn and add crimp or other textures or colors after it's initially spun.

"There are a lot of different properties we can build into the fiber," said Brad Nations, vice president of manufacturing, Unifi. "We can make it leaner, fluffier, take multiple colors or fibers and blend them together—there are a lot of possibilities."

Unifi CEO Eddie Ingle said the company continues to look for ways to automate its processes, which he says benefits employees because it eliminates potential injuries while also giving workers a more varied, engaging workplace.

"We try to automate as much as we can from an ergonomic standpoint," he says. "We took away a lot of the repetitive work that would cause carpal tunnel issues and boredom."

That combination of automation and human contact allows Unifi to up the sustainability story of its Repreve product by incorporating environmentally friendly practices during the production process. The Yadkinville plant, for instance, is a landfill-free facility. Not only does the company collect and sort all refuse to go to recycling or composting facilities, but it also utilizes the precision of automation to significantly reduce waste produced during manufacturing.

"Every step of the way, we’re constantly looking at how we can reuse, how we can reclaim," Joyner said. "We try to monitor closely to generate as little waste as possible."

As Repreve has become more widely used in everything from clothing and shoes to furniture and industrial applications, Unifi continues to expand its sustainability story. The company launched its Repreve our Ocean program, which sources plastic bottles found within 50 miles of an ocean or waterway. And its TextileTakeback program allows the company to take apparel fabric waste and recycle it into new textiles.

"We created Repreve to find new solutions for both post-consumer plastic and pre-consumer waste," Ingle said. And he emphasized that the company will continue to work to expand that mission for years to come.

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