Essentium TPU 90A-FR flame retardant

Essentium is an American industrial 3D printer and technical filament manufacturer, with branches in Asia and Europe. They have been leading the way into Industry 4.0 with their innovative materials and solutions, thus helping many companies not only prototype but also manufacture on a large scale in-house while maintaining product quality and reducing production costs. The Essentium catalog is full of high-end advanced filaments, mostly polymers and blends designed for strength, flexibility and high mechanical performance in challenging industrial settings. The Essentium filaments are popular across numerous disciplines and find many specialistic applications, for example in aerospace and defense, automotive, biomedical, contract manufacturing, consumer goods, and electronic manufacturing.

Technical filaments for professional uses

Essentium's TPU 90A FR (Flame Retardant) forms part of the manufacturer's impressive material portfolio and belongs to the group of flexible filaments. This filament is composed of < 70 % thermoplastic polyurethane. The remaining 30 % is a flame retardant substance and the 1,3,5-Triazine-2,4,6(1H,3H,5H)-trione chemical compound.

Thermoplastic polyurethane (TPU) is a thermoplastic elastomer composed of linear block copolymers, with alternating sequences of hard and soft segments. TPU plastics are characterized by very high elasticity, and are sometimes called a bridge between rubber and plastic. They also demonstrate great resistance to abrasion, impact, tears and chemicals (thanks to polyester in the soft segments), excellent performance in both low temperatures (thanks to the polyether contained in the soft segments of TPU) and high temperatures, toughness and very high elongation at break (>500 %). TPUs are easy to process and 3D print due to the absence of warping and their tolerance to temperature contrasts. Nevertheless, using an adhesive, such as the Magigoo Flex, is always an advised provisionary method to ensure proper behavior of the filament. TPU hardness can be altered by changing the ratio of hard and soft segments in its composition. However, it should be kept in mind that the hardness of the final 3D printed piece largely depends not only on the material used but also on the printing parameters, and the geometry and fill of the 3D piece.

Video 1: An overview and demonstration of TPU properties. Source: Essentium.

First experiments with thermoplastic polyurethane started in the mid 1950s and by the end of the decade a breakthrough appeared in the form of a shoe adhesive. Nowadays TPU has a wide range of applications in the automotive industry, sports, medicine and manufacturing for glass lamination, film and sheet, drive belts, fire hose liners, hydraulic hoses, flexible tubing, wire and cable coatings, in-line skates, caster wheel, inflatable rafts, flexible phone cases and many more. TPU is the perfect material for 3D printing pieces that will be subjected to all kinds of impacts and stretching.

Flame retardant properties

Since 3D printing is being adopted in such a wide range of industries, some with very specialized demands, 3D filaments need to meet those advanced needs. In some environments fire is a high risk and every precaution must be taken to prevent a fire or inhibit its spread. Flame retardant materials do exactly that, allowing for safe evacuation of personnel and damage control. In some industries (automotive, aerospace, electric/electronic, construction, civil engineering) the use of flame retardant materials is an obligatory safety standard measure. Flame retardant filaments normally consist of an engineering grade thermoplastic and a flame retardant additive whose role is to slow down the combustion rate, reduce smoke or limit dripping. The Essentium TPU 90A FR filament has as its base the certified for flame retardancy UL94 V0 resin. Its combustion stops within 10 seconds and if dripping occurs, the dripping particles are not inflamed.

Essentium Flame Retardant TPU 90A has been engineered to have the perfect balance of flexibility and toughness. Its Shore A rating of 90 A places it in the range of 85-95 A, the standard rating for flexible filaments, making it a semi-rigid filament. Any filament within that range is soft enough to be flexible but hard enough not to deform easily. Moreover, the Essentium TPU 90A FR exhibits excellent interlayer adhesion and high strain at break.

Apart from having the perfect balance of elasticity and toughness, the Essentium TPU 90A FR’s flame retardant properties make it perfect for pieces that need to act as flame retardants while being flexible and resistant to constant use and abrasion. Example applications would be flexible hinges, belts, plugs, gaskets, protective cases, overgrips, wheels, vibration dampeners or energy-absorbing lattices. Essentium recommends TPU 90A FR for the aerospace, automotive, contract manufacturing, defense, and consumer goods industries.