Functional sportswear is taken for granted nowadays. It is quite unexceptional for a sports jacket, for instance, to be both waterproof and breathable. In the case of working clothes, the functionality is mostly restricted to personal protection against fire, sharp objects, chemicals and so on, with wearer comfort (mostly) not being significance top priority. Bullet-proof vests made of Kevlar, as their name suggests, hold off bullets but they are also impenetrable for water vapor. Thus police personnel who must wear such gear under their uniforms sweat profusely when the weather is warm. A situation that is merely uncomfortable when working in the office negatively affects the physical performance of police officers on duty.
Empa has, therefore, together with its industrial partners, developed a smart protective vest with an integrated cooling system based on the Coolpad technology, originally designed for use in cooling garments for medical applications. The Coolpads built into the vest are filled with water, which is allowed to evaporate through the membrane, cooling down its surroundings. A mini fan blows air though a fabric spacer behind the pad, providing further cooling.
Integrating such an A/C into a garment proved to be quite tricky. It required a novel fabric spacer, which was stable under pressure yet also flexible and soft to the touch, and which offered very little resistance to air flow. A suitable spacer was developed together with Swiss textile manufacturer Eschler. Likewise, there were no fans on the market, which were small enough to be built into the vest; so Empa engineers designed a miniaturized version themselves. Two units including batteries and control electronics now provide the cooling air circulation in the vest. Similarly, the cool pads used till then proved unsatisfactory since in the protective vest they were mechanically quite stressed they frequently leaked water. A new technique for welding the ultra-thin pad me
|Contact: Markus Weder|
Swiss Federal Laboratories for Materials Science and Technology (EMPA)