We tested the transparent PU Film material adhesive: Terrible evaporation!
To really experience the breathability of the transparent PU Film material, our CEO conducted an experiment. He is a sports enthusiast, as you may have seen in our previous article, also as shown in the figure below.
We purchased a product from the market made of PU Film material. It is a common round transparent style with a pad in the middle (to avoid sticking to the sensor). Two hours before his recent basketball activity, our CEO applied this adhesive. Everything looked fine at the beginning, but during the basketball game, it was clearly visible that due to sweating, water marks (it was sweat) gradually appeared under the originally flat transparent PU Film, and this part accumulated more and more sweat. After two hours of a basketball game, the part without adhesive (but with a pad) could clearly be seen with a lot of sweat. Because the overall sealing is very good, the sweat was like water sealed in a plastic bag, soft and elastic, but without an outlet. Here are the conditions 1 hour, 4 hours, 6 hours, and 10 hours after this basketball game. Clearly, after a large amount of sweating exercise, this sealed area (which is the location of your CGM sensor) will always be very humid, and the duration could be as long as 10 hours. This sweat will always be trapped against the user's skin, and your CGM sensor will also be soaked in sweat during this period.
Let's also analyze it theoretically. The so-called breathable standard of this PU Film (if they can achieve it) is 500g/m²/24h. In the above test, all sweat was concentrated in a circular area with a diameter of 2.5cm, which is a range of 4.9cm². According to the standard, its theoretical 24-hour water vapor evaporation is 0.245g, and the average hourly evaporation is 0.01g. For your reference, a water droplet weighs about 0.1g. Imagine how many drops of sweat you will produce during a workout or in daily life?
In summary, perhaps this adhesive can prevent external water from entering, but the evaporation is terrible. Kovoq's highly breathable fabric, waterproof treatment and corrugated adhesive process ensure that we have unmatched waterproof and breathable properties compared to PU Film, which guarantees longer-term use and better comfort.