Currently kevlar can only be repaired with a welder or soldering iron, which means that a small amount of clothing can’t be repaired with sewing equipment (wooden needle, sewing kit, tailoring kit, etc.) even though it really should be.
I’m not sure if kevlar in game is for some reason ‘solid’, but cursory research suggests that most kevlar is woven into a fabric before being used, especially in body armor.
This suggests that you should be able to repair/reinforce clothing made of kevlar with sewing equipment. This is supported by the fact that the player is able to pad out existing garments with kevlar using a tailors kit.
The main reason I discovered this issue was that i found certain pieces of clothing, made only or primarily of kevlar, can’t be padded with extra kevlar to improve their armor rating, which seems unrealistic and inconsistent.
Sorry if this is in the wrong category, I’m currently on mobile and can’t very well tell which is which.