All hard case luggages are durable and therefore offer the best protection of the items inside. The most popular material for hard case luggage is polycarbonate, aluminum, ABS and polypropylene. The aluminum suitcases luggage are at the top of the range (durability, price), followed by polycarbonate(PC), polypropylene & ABS.
Aluminum suitcases have been around for a while and are classic choice. However, they are expensive and therefore increasingly being replaced by other less expensive hard materials such as PC & ABS.
Polycarbonate(PC) is molded type of thermoplastic polymers and is very popular material for hard case luggage. It is lighter than aluminum but still very durable and offers more style choices, e.g. in colors and patterns.
Another important benefit of polycarbonate as luggage material is how impact resistant it is. Upon impact, the material flexes to absorb the impact and then flexes back to its original shape, making polycarbonate luggage extremely resilient to rough handling.
Polypropylene, or polypropene, is also type of thermoplastic polymer and the lightest of all the thermoplastic products, making it ideal material for any lightweight luggage range.
Polypropylene is also very resilient (though not as much as polycarbonate). Polypropylene is great choice for those travelers that want good protection in as lightweight form as possible.
ABS (acrylonitrile-butadiene-styrene) is a common thermoplastic. ABS is lighter than polycarbonate but not as durable. It is also the cheapest hard material, meaning it is popular in the cheaper hard-sided luggage ranges.
ABS is frequently added to other stronger luggage materials, e.g. polycarbonate. The combined material is more durable than ABS on its own but also lighter and cheaper than polycarbonate on its own.