TFL Cool System - chills even the sun

How does the TFL Cool System work? The TFL Cool System is based on practical physics. Dark colours absorb sun radiation and, therefore, heat up more strongly than light colours, which reflect up to 95% of the light energy and thus remain cooler. The visible range of the human eye is between 400 and 700 nm (0.4 - 0.7m). The spectral distribution of the sunlight, however, goes far beyond that range. Humans cannot see in the UV and near infrared sector (NIR range goes from 700-25000nm). In the near infrared region the light energy absorbed by dark surfaces is transferred into heat energy, which heats up the material and then radiates as warmth. Materials and surfaces which employ the TFL Cool System do not absorb rays in NIR but rather reflect it. As a consequence, darker surfaces especially will not heat up so much. Graph1 above shows the spectral distribution of the sunlight. The rainbow colours identify the area visible for the human eye. Each colour, dye and pigment, has its own reflection curve. In general, white is strongly reflective in the visible area as well as in the NIR, while black is absorptive in both cases. Thanks to the TFL Cool System black is only absorptive in the visible area, ie it appears black, while in the NIR (near infrared area) it is reflective, ie white. Graph 2 highlights the principle: black COOL leathers behave like light coloured, reflective leathers in the invisible infrared area. Since the light energy is now reflected in the NIR, less heat energy is formed and the leather remains cooler. The temperature difference between standard and COOL leather increases with the duration and intensity of sun exposure. In extreme cases the temperature difference can amount up to 40°C. Why does the TFL Cool System work? Let's have a look at a simple example: Water is transparent, ice and snow, however, are white - why? Through formation of crystals inside snow and ice, light is reflected in a diffuse way and, therefore, appears white. The fibre structure of the skin also leads to a diffuse reflection of light, which means that light energy is not absorbed and, therefore, not transformed into heat. Dyes and /or pigments normally destroy this characteristic of leather. However, with the special dyes and pigments of the TFL Cool System these characteristics are conserved in the NIR. Crust leather dyed with the special Sella Cool dyes reflects the NIR rays which even penetrate the finish coat as far as the unique Roda Cool pigments which were being used. Looking at COOL and standard leather through a camera and with the help of a red filter, removing the visible area of 400 - 700 nm (this means you make the near infrared area visible for the human eye), COOL leather appears white and standard leather black. The motorbike jacket pictured is being heated by a lamp imitating sunlight. The monitor behind shows the jacket how the infrared camera sees it: standard leather (left half) is black, COOL leather (right half) is white. Automotive leather To further prove the effect of the TFL Cool System, two identical cars were equipped, one with COOL and one with standard leather. Graph 3 shows surface temperature of black coloured front seats (closed car) after different times of sun exposure: solar reflective leather blue line, standard leather red line. Even after 4-5 hours of sun exposure a significant difference in temperature (approximately 8-10°C) between COOL and non cool leather is still noticeable. The effect is especially pronounced on areas with strong exposure to sun like dashboards, steering wheels and seats. Differences are visible although the windscreens already have some NIR reflective properties. Yellow and dark blue lines in the graph indicate temperatures measured in the shaded area. Here no significant temperature difference is noticed. If a similar test is conducted in open cars (convertibles) the difference in surface temperature is even bigger (up to 20-25°C) due to the missing effect of NIR absorbing windscreens and the lack of convection heat. Motorbike suits/garments The cool effect could also be proven for motorcycle garments. The temperature difference inside a jacket amounted to 20°C and more. This means no more sweltering in leather garments! Motorcyclists are enthusiastic about COOL leather, employing the unique TFL Cool System. Dark COOL leathers reflect the sunlight in the same way as light coloured leathers. The advantage: the temperature of the leather surface stays up to 20°C lower. Even if you are standing in the blazing sun, inside your leather suit temperatures stay cool. Shoe leather COOL shoes offer improved wearing comfort. The sunlight is reflected, therefore less heat is produced, thus the climate inside the shoe is improved. Inside black shoes temperature differences of more than 15°C could be measured. What is the customer's opinion about the TFL Cool System? According to Th Lütje, CEO WLL Lütje Leder GmbH, Elmshorm/ Germany:'The TFL Cool System is a development which greatly improves the comfort of motor bikers bothered by heat. Latest physical findings in connection with the natural product leather indicate what I call customer oriented performance. A major reason for every motor biker to choose leather clothing.' Matthias Runde, graduate engineer (FH), BMW adds: 'The use of leather in the motorbike garment segment has steadily decreased over the last 20 years. Textiles have superseded leather in many fields of application as they are perceived as lighter and more comfortable. Therefore, it is all the more important for the timely introduction of TFL's new development. The innovative COOL technology provides a major improvement of the climatic and wearing comfort of biker clothing. Given the expectations of our customers, the COOL technology helps to fortify and strengthen the innovation leadership of BMW Biker equipment.' Benefits which customers enjoy * Increased comfort thanks to cooler leather * Better passive safety, eg for motor bikers * Improved ageing behaviour: The Arrhenius law states that a decrease in temperature of 10°C halves the rate of chemical reactions. Since COOL leathers heats up less, part of the ageing effect induced by heat is reduced. * Possible energy reduction for air conditioning units in closed cars How to implement the TFL Cool System? In order to take full advantage of the temperature reduction properties of TFL Cool Technology it is mandatory to use both the special Sella Cool dyes for dyeing the leather crust as well as the Roda Cool Pigments for the finishing coat. Partial substitution of COOL colours and pigments with regular ones can reduce or even fully destroy the performance of TFL Cool Technology. How can we make sure a leather is cool ? Based on the ASTM method, TFL have developed a practical test method using a special spectrophotometer working in the critical NIR range. The method employs a special measuring device linked to a PC. The measurement itself is fast, taking just a couple minutes determining the % of reflection at 980 nm. By definition a reflection of 60% or more gives COOL leather with a significant temperature difference. Intellectual property rights TFL together with IPS developed the COOL technology for leather. IPS owns the worldwide patents in major industrial countries and granted TFL the exclusive rights for marketing this technology. By using TFL's special Sella Cool and Roda Cool pigments the user automatically has the license to use this unique technology.