It’s easy to say thermoplastic: each material used has different characteristics and components. And not all of them are the same. Here is a guide to find your way around the purchase.
The Helmet was born many years ago, at first as a protective cap for wind and weather. Usually associated with goggles, then gradually modified in the structure, has become more robust able to cushion blows and remain more supportive with the body. The initial leather gave way to metal and leather, then to plastic up to modern synthetic materials of different nature. From hat, it changed its shape to side and back protection, increasing volume and consistency but also weight. It integrated the visor and further diversified shapes and design according to the most varied uses.
Synthetic materials had an evolution and experimentation was directed towards different types. The helmets are produced in materials, more or less valuable and with different qualities of resistance: Abs, polycarbonate, glass fiber, carbon fiber or Kevlar. To tell the truth, one cannot speak of resistance as an absolute factor. The materials as we know them can have different qualities, differences ranging from absorption to different breaking point. Nowadays a helmet is made of certain materials for the outer shell, then there is the inner shell and the padding. Every part of it can contribute to protection. The combination is very important.
Certainly the outer shell is the one that has the greatest influence on the quality of the final product. It ‘s the one that covers the most important function, the one that must resist any impact or rubbing and disperse and distribute the energy in the helmet itself. It is subjected to thermal stress, bad weather and accidental impacts. The material can also be decisive for the final weight.
Sometimes saying that the outer shell of the helmet is made of thermoplastic is seen as a “decrease” for manufacturers of this type of accessory. But between the various plastic materials it is easy for the end consumer to come up with something. What are the differences between the compounds of the outer shell? In this guide we explain everything you need to know to find your way around the time of purchase.
The thermoplastics family
Anything that can be shaped as a result of fusion-related transformation is called thermoplastic. It is a macrocategory that collects different materials, from polypropylene (the one used for water containers, to indendicion) to polycarbonate. The thermoplastic materials that, for technical and mechanical characteristics, are used in the production of helmets are basically two. On the one hand there is ABS, used for mid-range helmets, on the other polycarbonate which has mechanical characteristics superior to ABS. For low-end products, on the other hand, SAN (which is an ABS with a low butadiene content) is used.
Differences and peculiarities
What are the differences between the two? Generally speaking, polycarbonate costs more and weighs more than ABS. In addition, polycarbonate needs to be stabilized to ultraviolet rays (whereas ABS does not need this processing) and is more difficult to paint than ABS. In addition, there are so-called blended materials. These are thermoplastics obtained from a mixture (in variable composition) of polycarbonate and ABS.
The inner shell: it is normally made of polyurethane foam or polystyrene, a component that ensures good value for money with excellent sound and thermal insulation and energy dispersion. On the latter are applied additional finishes that act as insulation (the polystyrene does not like moisture or sunlight and weathering in general). Inside the helmet there are then the elements of the padding. This is important that there are no seams, that it is made of breathable, washable and hypoallergenic and antibacterial material. Everything must be removable and washable and repositionable. It is important that the padding itself has selectable and distributable elements for the greatest possible comfort and for the best transpiration and passage of air flows.
How a helmet should fit: the helmet should fit like a glove. Just a little bit tight. It must form a whole with the head. It must not be able to move. Over time, the padding will give way to the shape of the jaw and face. Obviously it must not give a sense of excessive constriction or hurt. The importance of a “right” helmet can be found at high speeds, with minimal vibration and unfortunately if you fall, it will not move causing further damage. The locking systems can be of various types. The safest have always been considered the double ring ones, but the comfortable and fast spring-loaded quick release fasteners are becoming more and more popular.
The visors are of various types, made of plexiglass or polycarbonate, thicknesses vary, resistance and transparency. But what I would like to remember is the presence – in the latest models – of the double visor of which a dark one, operated with external control, very practical, to be preferred to sunglasses.
Very important is the ventilation system that helps to avoid fogging in winter. The ventilation system is also very important for the disposal of heat inside the helmet itself. In summer, when the heat is stifling and the sun is hitting hard, it is important to wear a helmet that lets you breathe well, that does not attract the sun’s rays (as clear as possible). Lately, perforated helmets have come out, which will certainly improve the situation a lot.