BY FERNANDO SAINT AMOUR DI CHANAZ
Perfectly rounded glass beads have the unique property of sending light back to where it came from, as cat’s eye, same example of this phenomenon. Everyone has probably seen a cat whilst driving in a dark street during the night: the night running cat, especially if black, looks like two white light lamps. This is exactly the optical principle behind retro reflective materials based on glass beads used for high visibility purposes on road signs, asphalt paints or safety garments. The light bean emitted by the car will penetrate the glass bead (or the cat’s eye), it will be reflected back into the driver’s eye thanks to the property that a rounded glass bead will reflect a bean right to the light source direction.
This technology based on glass beads was invented back in 1930 by 3M, it has been used on a wide range of products for technical purposes. Whilst road paint implements glass beads on a white backing, high visibility garments must provide higher reflectivity complying with severe international standards regulating all aspects of reflectivity before and after washes.
Therefore high visibility garments utilize this same technology, but in this application glass beads are applied onto a metal coating to maximize retro reflectivity value. Therefore the reflective textile transforms a conventional garment into a safety gear complying with international norms like ISO20471 (for EU) or ANSI/ISEA 107 (for USA). The EN471 certified garments must provide retro reflectivity values before and after a nigh number of industrial washes. These garments however are often produced and commissioned by Public Tenders and they are ranked as Personal Protective Equipment (PPE).
This technology is nowadays applied onto a wide range of garments and textiles used by people circulating in the streets during the night: road workers, baby trolleys, bicycle seats, running shorts, footwear, automotive seats. The intrinsic limit of this technology has always been the grey color produced by the metal coating backing the glass beads which makes all high visibility garments looking all the same.
Over the last 10 years this technology has shifted and migrated from high visibility safety garments designed for road workers into functional sport gear, footwear and garments designed for running, cycling, skating, skiing and many other sports. The retro reflective technology applied on sportswear provides additional value and makes the garment more technical. Furthermore the reflective material provides other functional value due to its decorative and elastic features. Therefore on sportswear reflective materials are also used as logos, to enhance the elasticity of the garment, as printed labels, as zipper pullers etc.
From one perspective the shift of reflective materials from Safety Garments to Sportswear has mainly impacted the products design, allowing brands to broaden borders of their creativity. From a different angle this shift also generated new requests pushing reflective material manufacturers to extend their product offer, invent new technologies and offer additional properties.
Retro reflective materials based on glass beads are currently available not only as the conventional heavy and rigid polyester trims used in safety garments. Retro reflective beads are applied also on elastic and soft heat sealable films, multi-color textiles, printed logos, color changing rainbow coatings, piping and many other products. Sportswear brands like Nike, Reebok, Lululemon, Adidas, Under Armor, Patagonia, Columbia, Millet have successfully implemented these materials onto their products and a wider range of new manufacturers emerged.
If the conventional technology offered high reflectivity materials with a single color (grey) new manufacturers developed highly reflective materials in many different colors and shades.
Whilst 3M has ranked retro reflective business as a low priority one, new manufacturers emerged in three continents satisfying the needs of the newly emerged sportswear opportunity. Over the last 10 years in Europe, America and Asia companies like Bemis Ass., Safe Reflection, JRC, IRC, Sto-Nor, Ms-Korea, Hj-Lite, Reflomax, Chinastars invested into new technologies and materials broadening the product offer and the technology limits to satisfy the needs of this newly emerged market.