How to distinguish between needle punched felt (liquid filter), Polypropylene(PP), and Polyester(PE)?
Polypropylene(PP) and Polyester(PE) are the most popular types in the liquid filter industry. When there are two pieces of felt in front of you, can you say which is PP or PE?
Here I list the differences to you.
Needle-punched felt for liquid filtration needs a finish treatment to lock the surface fibers. Without this step, fibers definitely will drop down into the liquid products to impact the quality.
As PP and PE have different temperature resistance, they are on other finish treatments.
1 – Polypropylene (PP) is doing glazed finish treatment. It’s smooth on touch. You can even see it’s more smooth in the picture.
2 – Polyester (PE) is doing singed filter treatment. Singed treatment is like fire on the surface to burn fibers. After singed treatment (burning), the PE felt surface would become ROUGH. You can even see it’s rough in the picture.
If you still do not get the point, you still cannot distinguish them on watch and touch, and we will go the second step: Burn them on fire.
3 – Cut a piece of Polypropylene(PP) media, burn it on fire. PP will melt without black smoke, solidify into glue solid.
4 – Cut a piece of Polyester(PE) media, burn it on fire. PE will be on fire, and black smoke will come out. The rest part will be like asphalt.
Now you see the difference.
