The disadvantages of polypropylene are:
Its post-cooled resistance to adding coatings such as paint or ink.
If the fiber becomes too hot, there is a tendency to break.
PP is highly flammable and will melt when exposed to heat. It has a flash point of 260° Celsius.
It can often suffer from chain degradation leading to oxidation, which subsequently results in cracks and crazing.
It is prone to damage from UV light.