Nylon: A Material with Legs

In a time when it was still scandalous for women to wear pants and bare legs were unthinkable,nylon came to the rescue as an alternative to silk and woolens. Developed by DuPont in the mid-1930s and exhibited at the New York World’s Fair in 1939, this thermoplastic was the world’s first completely synthetic fabric. It is now one of the most important engineering and manufacturing materials out there and is far more flexible—pun intended—than you might have thought.

Nylon went into commercial production by DuPont in 1939. Like polyethylene and polypropylene—all plastics, really—it is made by polymerizing a simple chemical structure into long strands of repeating molecules.

Nylon’s particular makeup gives it the silky quality that makes it a go-to substance for fibers. It was specifically developed by DuPont chemists in their search for an industrially viable material, and they had an immediate hit on their hands: Within two days after nylon stockings went on sale to the public, 4 million pairs had been sold.

 Tough cookie: nylon’s properties

If you’re researching possible manufacturing materials, you’ll most often see two compounds: nylon 6 and nylon 6,6. When injection molded, both are amorphous, as opposed to crystalline, meaning that their chemical structure gives them good impact resistance and stability. Through mechanical stretching, however, nylon can be made highly crystalline, giving you nice smooth fibers.

Two of its greatest qualities, however, are its heat resistance and its tensile strength. Thanks to these, nylon can be used in under-the-hood car parts, in mechanisms like gears, and as housing for cords and cables for power tools and electronics. Combined with being a fraction of the weight of many hard metals—not to mention a fraction of the cost—nylon is a good choice for some products that have multiple moving parts. And, of course, its tensile strength is why there are millions of miles of nylon rope in the world. Its extensive use in marine and automotive products attests to nylon’s ability to withstand harsh environments and use.

It’s tough stuff, nylon, with excellent chemical, ultraviolet, and wear resistance. Glass can be added to Nylon to add to its toughness. There is even a supertough, or ST, class of nylons, recommended for products that are destined for long lives of high, repeated impact.

 Nylon manufacturing and recycling

Among the big names in nylon polymer production are DuPont, BASF, Celanese, RTP Products, and Ensinger.

All types of Nylon are technically recyclable, but some of the processes are difficult and expensive. In injection molding, we can regrind different grades of Nylon and mix with virgin material at low percentages (10-20%). Aleast 60 percent of nylon’s use is in fibers and because nylon is so durable, the products that are made from it last for years and are not thrown away with the same frequency as other plastics. Reusable shopping bags, backpacks, suitcases, outdoor clothing, and other nylon fiber products get a lot of long use and can be repaired as well as donated to ensure they stay out of landfills for many years.

Several forward-thinking companies, including Patagonia, carpet maker Aquafil, and Bureo are creating closed product loops or specifically sourcing recycled nylon for their raw material. Bureo pays Chilean fishers to collect old nylon fishing nets (which are filling the world’s oceans), which it then turns into sunglasses and skateboards. Aquafil’s carpets become new fibers, sold under the name Econyl, that can be made into clothing. Speedo is now using Econyl in more than 50 products.

If you’re designing a product that has fibers, needs incredible strength and durability, or both, you probably have some nylon in your future.

For more info, check out these links:

https://en.wikipedia.org/wiki/Nylon_66

http://www.polymerprocessing.com/polymers/PA66.html

https://en.wikipedia.org/wiki/Nylon

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