Improvement to a plastic part of a protective helmet

Abstract

The invention relates to a plastic part of a protective helmet, characterised in that the parts undergo a treatment in order to improve the technical specifications thereof, in particular the mechanical strength of a part of a protective helmet at low and high temperatures, said treatment comprising the application of ionising radiation to the parts.

1 . A plastic part of a protective helmet, characterized in that the parts are subjected to a treatment to improve their technical characteristics and in particular the mechanical strength at low and high temperatures of a part of a protective helmet, said treatment consisting in subjecting these parts to ionizing radiation. 
     
     
         2 . The plastic part of a protective helmet as claimed in the preceding claim, characterized in that the part is made of plastic of the thermoplastic type. 
     
     
         3 . The plastic part of a protective helmet as claimed in the preceding claim, characterized in that the part is made of plastic of the thermoplastic type of the polyamide 6 (PA-6) type. 
     
     
         4 . The plastic part of a protective helmet as claimed in  claim 2 , characterized in that the part is made of plastic of the thermoplastic type of the polyamide 6,6 (PA-6,6) type. 
     
     
         5 . The plastic part of a protective helmet as claimed in the preceding claim, characterized in that the part is an outer shell of a protective helmet made of thermoplastic. 
     
     
         6 . The plastic part of a protective helmet as claimed in any one of the preceding claims, characterized in that the ionizing radiation is electron ionization. 
     
     
         7 . The plastic part of a protective helmet as claimed in any one of  claims 1  to  5 , characterized in that the ionizing radiation is photon ionization. 
     
     
         8 . Process for producing parts as claimed in any one of the preceding claims, characterized in that the process comprises the following steps:
 in a preliminary first step, the parts are produced from plastic, for example by thermoplastic injection molding,   in a second step, the parts are introduced into an ionizing chamber in order to be subjected to ionizing radiation, and   in a third step, the parts, once they have been ionized, are removed.   
     
     
         9 . The process as claimed in the preceding claim, characterized in that, before the injection molding, a coagent is introduced into the formulation, the aim of the coagent being to enable the bridging of macromolecular chains while the double bonds of which it is composed are opened. 
     
     
         10 . The process as claimed in the preceding claim, characterized in that coagent is from the methacrylate or allyl family. 
     
     
         11 . The process as claimed in the preceding claim, characterized in that the volume of incorporation of the coagent into the formulation is between 0.05% and 10% by weight.