Smartphones: Why transparent cell phone cases turn yellow

Boxes are included in the boxes mobile devices From manufacturers such as Xiaomi, Oppo or Samsung, they have a problem and that is that they always have a cream or yellow tone. This color change, even if you try, unfortunately cannot be avoided due to the material used in its production: TPU (thermoplastic polyurethane).

This polymer has many characteristics that make it ideal for making the first cases for smartphones. However, its degradation is what causes the gradual transition of the tonality of the material.

Covers have a simple function: it Device protection possible impact or fall and additionally change its appearance. Clear polymer does not satisfy the latter, but it is a favorable material because of its heat resistance, its great damping capacity, and its resistance to grease or oil.

Additionally, for the most eco-friendly of consumers, TPU is recyclable and can be used in elastic textile fibers, 3D printing, automotive components, shoe soles, among other industrial applications.

These advantages and the low cost of their production are what make it possible to include transparent cases in the initial set of smartphone accessories.

The main problem with these coatings, as mentioned earlier, is that when they break down, their color changes and returns to the original state of the polymer, which is yellowish. This process occurs when the casing is exposed to sunlight, which causes changes in the material at the molecular level thanks to the heat it generates.

It is better to buy another cover

Cases, both TPU and silicone, will break down due to exposure to sunlight and outdoor heat. So the question of whether there is any method to prevent this or reverse the process is natural. However, this is not possible regardless of how many chemicals are used in the casing.

“Tricks” such as using soap and water, cleaning the coating with isopropyl alcohol or soaking it in bleach are not effective and are a waste of time if you want to return the material to a clear state. What they do is disinfect and clean the casing, but as mentioned before, the color change is due to the degradation of the polymer, not the dirt that has accumulated on it as a result of its constant use.

Considering that the material is recyclable, then it is ideal for people who are worried about the yellow tone of the cover after a while and buying a new one.

In addition, the degradation period of the coating polymer is not fast, but it takes several months for the yellow color, so during the period of 2 to 3 years of the devices, it is likely that st. Only a few of them will be used at that time.

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