note: the part has a round diameter in the middle, so the thickness referenced is actually a diameter.

For online purposes, we conducted this using the yield strength of a generic grade of PP at room temperature which = 120Mpa. We also used the 4mm measurement to determine acceptability.

F = 100kg = 980 N

A = pi * r^2 = 0.00001257m^2

Tensile Strength = F/A = 78,000,000 N/m^2 = 78 Mpa

In this scenario, the maximum thickness of 4mm would be acceptable assuming the application is a low-risk application where the product is stressed for a short period of time.

Although this is a simplified example on how such a calculation could be performed since I have no specific information about the product or application.

-Andy