Helmet Liners made of molded EPP foam:

Most helmets today have liners made of EPS (Expanded Polystyrene), a great shock absorbing material, but it will be permanently compressed when absorbing an impact, even a minor one. Using multi-impact EPP (Expanded Polypropylene) as core material creates a helmet that will protect your head over and over again. To date, both traditional hard shell and in-mold helmets have relied on Expanded Polystyrene (EPS) for shock absorption. EPS absorbs energy by plastic deformation on impact and results in permanent deformation. As a consequence, a helmet liner made of EPS will not be as good absorbing repetitive impacts. It would be a trend that most safety helmets will use a liner of Expanded Polypropylene (EPP) instead of the traditional EPS. The difference between the materials is that EPP does not deform permanently, which means it’s suitable for absorbing repetitive impacts.

The molded EPP foam liner pads are used in military helmet,equestrain helmet,hockey helmet,ice hockey helmet,city bike helmet,skate helmet,ski helmet,water sports helmet,etc.