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Water-proof finished winter jacket part. Photo courtesy Roshan Paul.

What’s new in textile coatings and finishes.

The textile coating industry is a booming business— projects this segment of the fabric industry will grow from US$4.4 billion in 2023 to US$5.4 billion by 2028. Much of this growth is due to the popularity of textile coatings and finishes that can help extend a fabric&/aatccnews-2024-12a/8217;s life and grant it enhanced capabilities.

Example of coated textile. Photo courtesy Roshan Paul.

“A coating or finish can improve the visual aspects of textiles and also provide desirable qualities such as softness, hydrophilicity, and handle,” explains , senior program manager at the , Germany. “And it is well known that a wide variety of technical properties can be created on textiles. In short, it gives (additional value) to the textiles.”

Let’s take a further look into the biggest advances in the textile coatings industry right now, as well as two new coatings showcasing the great progress of this industry.

Current Trends

As functionality and performance continue to be important aspects of textile coatings and finishes, Paul says that the Covid-19 pandemic was a turning point in textile finishes and coatings. It spurred a great deal of research into new coatings that are not just antimicrobial, but that can also repel and even kill viruses and bacteria.

&/aatccnews-2024-12a/8220;Virus protection was not possible before Covid-19, but we have several products now,&/aatccnews-2024-12a/8221; he explains. &/aatccnews-2024-12a/8220;Overall, medical textiles got a big boost, with never-before performance parameters now [achievable]. However, safe disposal and moreover, the recycling of these PPE products are very important, and should be�� done in a proper way, in the future.&/aatccnews-2024-12a/8221;

As sustainability continues to be a trend in the entire textile industry, Paul says it is also fast catching up in the area of coatings and finishes.

&/aatccnews-2024-12a/8220;I would like to stress that biotransformation of the textile industry, regenerative manufacturing, sustainable practices, and circular designs, such as Safe and Sustainable by Design (SSbD framework) are getting more [important] these days,&/aatccnews-2024-12a/8221; he continues. &/aatccnews-2024-12a/8220;For [example], this is particularly relevant for perfluoroalkyl and polyfluoroalkyl substances (PFAS)-based hydrophobic finishes, by replacing them with bio-based solutions, based on anchor peptides. Anchor peptides-based biohybrid flame retardants have been also developed recently. Talking specifically about textile coatings, detachable coatings, based on triggerable smart polymers, hold the key in the recycling of coated textiles.&/aatccnews-2024-12a/8221;

Paul says there has also been a lot more adoption of advanced fabric coating technologies like plasma coating, ultrasonic spray coating, nanocoating, and digital printing in the textile industry. &/aatccnews-2024-12a/8220;Plasma has some limitations—as of now, it is still not possible to apply on [an] industrial scale continuous process,&/aatccnews-2024-12a/8221; he continues. &/aatccnews-2024-12a/8220;Ultrasonic spray coating and nanocoating will be very important in [the] future, but nano-safety aspects should be [considered]. I see huge potential for digital printing, as it is sustainable, saves ink, water, and [has little to] no effluent.&/aatccnews-2024-12a/8221;

Upcycling Old Clothes

Photo courtesy Juan Hinestroza

Speaking of sustainability, finding a way to reuse the estimated 92 million tons of textile waste produced globally each year was the impetus for , the Rebecca Q. Morgan ’60 Professor of Fiber Science & Apparel Design and director of the Textiles Nanotechnology Laboratory in the College of Human Ecology at , to create a &/aatccnews-2024-12a/8220;universal finish&/aatccnews-2024-12a/8221; through .

&/aatccnews-2024-12a/8220;Maybe 10 years ago, I was in the Himalayas and I saw a little kid wearing a T-shirt from an American university,&/aatccnews-2024-12a/8221; he recalls. &/aatccnews-2024-12a/8220;I tried to figure out if the kid was related to the school or the family. Turned out to be that they just picked up that T-shirt from a garbage dump. After looking at the massive amount of textile waste, I decided to work on what to do with the waste.&/aatccnews-2024-12a/8221;

Hinestroza and his team developed a process in which old textiles were cut into pieces and chemically decomposed into a &/aatccnews-2024-12a/8220;soup&/aatccnews-2024-12a/8221; of raw materials, additives, dyes, dirt, and other impurities normally found on old clothing. From there, the researchers added a metal solution to the &/aatccnews-2024-12a/8220;soup&/aatccnews-2024-12a/8221; that shares an affinity with polyester. This then creates tiny cages called metal-organic frameworks that sink to the bottom of the &/aatccnews-2024-12a/8220;soup.&/aatccnews-2024-12a/8221;

&/aatccnews-2024-12a/8220;We found ways in which we can control the depolymerization of polyester, which can &/aatccnews-2024-12a/8230; use some of these metal-organic frameworks to selectively find the molecule that we need to extract,&/aatccnews-2024-12a/8221; Hinestroza explains. &/aatccnews-2024-12a/8220;That type of chemistry is called reticular chemistry and that chemistry allows us to find only the molecule that we need, and [thus, we] don&/aatccnews-2024-12a/8217;t have to purify the soup.&/aatccnews-2024-12a/8221;

The metal-organic frameworks can then be used to make fabric coatings, such antibacterial, anti-stain, and anti-flammable, Hinestroza says, by just slightly modifying the chemical composition of the metal-organic framework.

Since Hinestroza&/aatccnews-2024-12a/8217;s initial research published in March 2023, he says his lab has been working on creating new types of textile coatings using this method, such as oil resistance and color fastness. &/aatccnews-2024-12a/8220;The idea is to create what we call a universal finish, so a single molecule will be able to produce all these effects like anti-wrinkle, stain resistance, [flame] resistance, or antibacterial resistance,&/aatccnews-2024-12a/8221; he adds.

Cooling Textile Coating

Another hot (pun intended) area of interest in the garment industry right now is finding a way to cool down a person through the clothing they wear, says , professor of chemistry and chemical engineering at the .

&/aatccnews-2024-12a/8220;[With] rising temperatures across the world over the next 30 years, there are multiple parts of the Middle East, Southeast Asia, &/aatccnews-2024-12a/8230; Africa, and parts of North America and South America close to the equator that are going to become uninhabitable because of the average temperature of those locations,&/aatccnews-2024-12a/8221; she explains. &/aatccnews-2024-12a/8220;And so, the idea of trying to [control] that kind of heating using clothing is a very practical one. Urban environments also are incredible heat deserts, and there are long standing efforts in trying to cool buildings using methods other than HVAC systems and air conditioning, because those are incredibly energy intensive.&/aatccnews-2024-12a/8221;

The coated swatch is on the bottom. Photo courtesy of Tricia Andrew.

Andrew is the lead author of recently presented at the Fall 2024 meeting. The research features a new chalk-based textile coating she and her team developed capable of reflecting infrared light from the sun—called optical heating—away from the body. This results in cooling the air underneath the treated fabric by up to 8^○ F.

The coated swatch is on the left. Photo courtesy of Tricia Andrew.

&/aatccnews-2024-12a/8220;In this particular case, we were inspired by nacre, which is found in abalone shells &/aatccnews-2024-12a/8230; [and] other shellfish,&/aatccnews-2024-12a/8221; Andrew says. &/aatccnews-2024-12a/8220;This is why a lot of folks, especially around the Mediterranean and Southeast Asia, paint their buildings with ground up calcium carbonate &/aatccnews-2024-12a/8212; it&/aatccnews-2024-12a/8217;s really ground-up shells from these marine animals that reject IR light, and the chalk is that.&/aatccnews-2024-12a/8221;

The fabric coating created by Andrew and her team is a four-layer structure. They were able to apply the coating to each fiber of many commodity fabrics through a technique called chemical vapor deposition. &/aatccnews-2024-12a/8220;We have a four-layer structure that&/aatccnews-2024-12a/8217;s alternating between calcium carbonate &/aatccnews-2024-12a/8230; [and] also barium sulfate, and it is the alternating mixture of the two that actually gives us the performance that we&/aatccnews-2024-12a/8217;re able to see,&/aatccnews-2024-12a/8221; Andrew adds.

With innovations like these, it’s obvious there is still much more to come in the world of textile finishes and coatings.

��ɫֱ�� the Author

��is a journalist, editor, and freelance writer with more than 25-years’ experience. A former associate editor for��Nonwovens Industry, her byline can be found in a variety of consumer and trade publications, with past and current clients including��Medical News Today, IAAPA’s��Funworld Magazine,��Rinksider Magazine,��International Bowling Industry��magazine, and��HomeTalk.com, as well as����ɫֱ��Review��and����ɫֱ��News.