What Makes Kinetic Stretchy and Resilient
Kinetic is one of our favorite fabrics - it’s moisture wicking, wrinkle resistant, incredibly stretchy and resilient. But stretch and resilience don’t always go hand-in-hand - we’re all all too familiar with t-shirts, chinos and jeans that stretch out and lose their shape, leaving baggy knees and an inconsistent fit from wear to wear. Here’s our innovative approach to creating a fabric with crisp structure, with un-restricting stretch.
Early Approaches to Stretch
Initially stretch was incorporated into fabrics through what is known as “mechanical stretch”, an inherent “give” in a fabric that was a function of its weave or knit construction.
Knit Fabrics: T-shirts and garments like our Apollo shirts are quite stretchy inherently because of their looser fabric structure.
Woven Fabrics: Diagonal stretch found in shirting and suiting, known as “bias stretch” - this generally doesn’t stretch horizontally or vertically.
Spandex - A Revolution in Stretch
Elastane - or as it’s commonly known, “Spandex” - was developed about 60 years ago, and has unlocked the ability to have woven and knit fabrics stretch significantly, for high-stretch shirting, base layers, bike shorts and much more. (Fun fact, spandex is an anagram of “expands” - thanks Wikipedia.)
A little bit of spandex goes a long way. We use 2%-6% spandex by weight in our Aero shirting, enough for comfortable stretch without sacrificing crisp structure.
Kumar, Bipin & Das, A & Alagirusamy, R. (2013). An approach to examine dynamic behavior of medical compression bandage. Journal of the Textile Institute. 104. 10.1080/00405000.2012.749573.
The Limitations of Spandex
The more you stretch a fiber - and the more times you stretch it - the more its recovery reduces. Think of a battery as an example - the more charge cycles you go through, the more you discharge each time. Spandex poses a similar challenge - after several hundred stretch cycles, it loses its ability to exert enough force to bounce back to its original shape.
Additionally, the chemistry in spandex is particularly susceptible to chlorine - typically found in bleach and pools, leading to further degradation of the fiber.
Spring-like Stretch - A Mechanical Inspiration
The solution to truly resilient stretch was inspired by one of the simplest mechanical devices - a spring. Springs rely on geometric structure (a helix) over chemical structure, to create stretch with great bounce-back (also known as “recovery”).
From our previous discussion on Kinetic’s Bio-Based Polyester, we know that we utilize a special construction called “bi-component” fiber, made of two different types of polyester sandwiched together. The yarn is extruded at high temperature, but as the filament fiber cools, the two polyesters shrink at different rates, causing the fiber to create a spiral-spring structure.
The resulting fiber can stretch significantly hundreds of times with without losing its shape or structure
Warp Knit - Stretch and Structure as One
While traditional “Weft" knits are stretchy, they lack structure of traditional woven garments. Woven fabrics, typically chosen for shirting and suiting because of their crisp structure, lack the ability to stretch significantly.
Kinetic is made using a third construction technique called “warp-knitting,” which combines the stretch of weft knitting with the structure of a woven. The machines used in this process are a cross between a knitting machine and a weaving loom. While it’s slightly slower than regular knitting and weaving, it results in an exceptionally durable, stretchy and resilient fabric.
Woven, Warp and Weft Knitting Compared. Warp-Knitting is a blend of the two other common types of fabric.
Conclusion
The result of all of this is that Kinetic is a fabric that combines yarn technology with premium knitting techniques to create stretch fabric with great shape retention - perfect for daily wear and easy care.