Paper corner protectors are usually made of paper or cardboard, so they do not have sun protection properties. Paper corner guards may become damaged or discolored after prolonged exposure to sunlight, especially strong sunlight. Sun exposure can cause paper to become brittle, fade in color, and even cause it to gradually break down.
If you will be using it outdoors or exposed to the sun for extended periods of time, you may want to consider other more durable materials, such as plastic corner guards or metal corner guards, which are better able to withstand the effects of sun exposure and environmental factors.
Overall, paper corner guards are not an ideal choice for withstanding sun exposure, and if you need to use them outdoors or require longer-term protection, other options should be considered.