PP Strap for Semi Automatic Machine Polypropylene, Polyester and Steel are the most used strapping materials. All three have their own benefits and limitations and their selection depends on the specific needs of the industry. Bands made by these materials are named as Polypropylene strap (PP strap), Polyester Strap (PET Strap) and Steel strap. These straps are made using Fully Automatic Machines, Automatic Machines and PP straps for Semi Automatic Machine. PP Straps are most preferred by wide range of industries because they are economical and can be used in wide variety of applications. What is PP band? PP here stands for Polypropylene strapping. Two Bands are connected by Heat Welds with the help of handheld tools or PP strap for semi automatic machine and fully automatic machine.