Case Study

Natura Sewing Thread: Little Things Make a Big Difference

Natura sewing thread is available in 14 stock colors and four different weights, is Cradle to Cradle Certified™ at the Gold level, and is part of the Fashion Positive Materials Collection.

As in life, so it is in fashion: It’s the little things that can make the biggest difference. Take sewing thread—without it we would have little structure to our clothing, few details in our accessories. Yet its composition and impact have historically been ignored, and so we find ourselves in a fashion landscape where a botanically dyed, locally grown organic cotton T-shirt is sewn using a fossil-fuel derived, non-biodegradable polyester thread. “That’s a problem: sewing up a biological material with a technical material,” said Annie Gullingsrud, the director of Fashion Positive at the Cradle to Cradle Products Innovation Institute. Biological materials can biodegrade and technical materials can potentially be recycled, but when they are inseparably combined in the same garment neither can happen.

If you were a designer or brand and wanted a biodegradable thread to hold your sustainable fabric together, you were out of luck. Then Johann Mueller AG, a Swiss company with more than 170 years of history in bleaching, dyeing and finishing yarns and fabrics stepped in. Natura sewing thread, available in any Pantone color, plus 14 stock colors and four different weights, is Cradle to Cradle Certified at the Gold level and part of the Fashion Positive Materials Collection.

But the route to certification, and circularity, was anything but straightforward. Where did the difficulty lie? “Nobody wanted to take the challenge,” said Albin Kaelin, CEO of EPEA Switzerland, one of the independent assessors who ensures that products meet the Cradle to Cradle certification standards. “When we confronted the sewing thread manufacturers with this issue 13 years ago, they didn’t want to deal with it.” Why? That was due to several reasons: “It’s because sewing yarn didn’t need much material, so companies didn’t see the market potential,” Kaelin said. “It’s also quite a demanding product—it’s not easy to develop since there are issues with adding color, shrinking and ensuring it performs in the sewing machine.” That last part is an important factor: yarns need to be finished with lubricants so they can move through the eye of a needle at the very high speeds that commercial machines run.

With thread producers disinterested in pursuing a product compatible with circular-design philosophies, Kaelin started thinking outside the box. Kaelin approached Johann Mueller AG, with whom he had a long had a relationship with via the Climatex fabric. (Climatex has the distinction of being the first Cradle to Cradle textile, way back in 1993).  

Johann Mueller AG said it would tackle the challenge. The company had part of the equation nailed down; it had the expertise for the dyes and special detergents needed for thread creation. Through plenty of trial and error, including use tests in high-speed sewing machines—making a lubricant that met the material health qualifications aspect of the equation was a particular challenge—it found success first with a 100 percent cotton thread, and then later with a 100 percent Tencel (cellulosic fiber of Lenzing) offering.

As demand for circular materials has expanded in recent years, the company’s early investment is reaping benefits: “It’s growing now and we’re now making more than 10 times what we did when we started the process,” said Markus Mueller, president and CEO of Johann Mueller AG.

The first certified yarn was made with special extra-long mercerized cotton, but the firm was always working to improve the product: “Later we found it was better to use Tencel, because it is stronger—it’s the strongest cellulosic, biodegradable fiber,” Mueller said. (Silk is the exception, but it’s cost-prohibitive.) “Production is done in a closed-loop process, so the sustainability behind making Tencel is at a very high standard,” Gullingsrud added.

Johann Mueller AG has been dyeing yarns and fabrics since 1845, so when it came to the five pillars of Cradle to Cradle certification, they were already well in-hand due to Swiss laws. The company had long used waste products to heat its water, having moved away from oil and  gas 20 years ago in a bid to become energy independent. A few years back they changed up its system once again, and now it runs on a combination of hydropower electricity from Switzerland and by burning waste woods: “We burn shredded wood, from pallets, houses, construction debris,” said Mueller, noting that it’s at a rate of over 2,000 tons per year. (If unused in this way, this kind of debris typically ends up as landfill.)

Good things in, good things out. That’s the mentality of Mueller.

Albin Kaelin, CEO of EPEA Switzerland​

The company also didn’t have much work to do when it came to social fairness, another one of the five certification pillars, because it’s been operating within its community for 170 years and abides by strict Swiss labor laws. To that end though, the company is doing something particularly innovative: Exploring ways to provide its excess power to nearby homes. It’s still in the pilot stage, but interested homeowners are signing up and a local utility company is figuring out how to get “district heating” power from the Johann Mueller AG plant to the people. 

Material health was the part of the Cradle to Cradle methodology that was hardest to meet at the Gold level, Kaelin said. Changes in the industry mean that the bulk of chemicals used for fashion come from Asia—which has infamous quality-control challenges (chemical formulations can change with each new batch of a needed ingredient). Fortunately, Johann Mueller AG has had relationships with European chemical companies for 170 years, which have a more stable—and consistently verifiable—ingredients list. “It’s still a huge challenge,” said Kaelin about ensuring that Cradle to Cradle Certified™ standards are met, but “because they have supply chain, knowledge and testing, we are able to ensure our Gold level certification benchmarks are being met.”

When it comes to Natura, Kaelin said it’s simple: “Good things in, good things out. That’s the mentality of Mueller.”  

Cradle to Cradle Certification

The Cradle to Cradle Certification process guides designers and manufacturers through a continual improvement process that looks at a product through five quality categories—material health, material reutilization, renewable energy and carbon management, water stewardship and social fairness. A product receives an achievement level in each category—Basic, Bronze, Silver, Gold, or Platinum—with the lowest achievement level representing the product’s overall mark.

Optimization Results for Mueller's Natura Sewing Thread

Material Health
Challenge: Other sewing yarns are made of non-biodegradable, non-recyclable materials, like polyester, which contains antimony, which is disallowed under the Gold level criteria. Similarly, they are often dyed and finished with chemicals disallowed under the standard.
Optimization: Chemistry of all detergents, dyes and lubricants was optimized to qualify for Gold level certification. Base sewing-thread materials, either cotton or Tencel, are biodegradable.
Material Reutilization
Challenge: Both cotton and Tencel are naturally biodegradable; dyes, detergents and lubricants could contaminate the fiber.
Optimization: When clothes eventually make their way to the earth, they contain no materials that will pollute. They are defined as a biological nutrient.
Water Stewardship
Challenge: Water effluent rules in Switzerland are strict, and localities further clean wastewater from factories.
Optimization: Natura thread was a new product, and Mueller knew what to expect from previous Cradle to Cradle certified products; water standards were built into product development.
Renewable Energy
Challenge: Johann Mueller AG has long been independent from fossil-fuel energy. It has used hydropower electricity and local waste wood to heat up the dyebaths for the last decade.
Optimization: Going above and beyond renewable energy requirements, Johann Mueller AG is attempting to use excess energy from its hot effluent water to heat local homes, also known as, “district heating.”
Social Fairness
Challenge: There were no labor issues or issues needed addressing for Gold level certification.
Optimization: No changes needed.