PPI is a foam resin of polyurethane. The open cellular structur with a controlled porosity (where pores’ distribution per material inch is costant) provides a minimum resistance to air passage but it has a great ability in retaining particles. PPI has excellent physical and mechanical properties, its resistance to detergents, fats, soaps and mineral oil makes it suitable in different conditions without altering its filtering power. PPI can be easily cleaned with water, industrial soap and other aqueous solutions.

The values of filtering and mechanical properties vary depending on the porosity level.