3-D Textiles Protect Against Extreme Heat Loads

The ideal complement to conventional protective clothing are functionalized, so-called three-dimensional undergarments. This newly developed protective clothing consists of a multi-layer structure in which the different layers assume different functions. The central role is played by a spacer fabric.

The protective effect of this spacer knit is based on the one hand on the avoidance of skin contact with the layers of protective clothing above, in order to prevent scalding caused by one's own body sweat, and on the other hand on a cooling effect produced by moisture removal. The knitted fabric works particularly well by producing locally different stiffnesses. The stiffness can be adjusted precisely on the machine side via the pile yarn and changed flexibly during the process.

In Germany, around 10 percent of the workforce are exposed to high temperatures at their workplaces, write the authors Lukas Lechthaler, Kristina Simonis, Marie-Isabel Popzyk, Christoph Peiner, Thomas Gries from the Institute of Textile Technology at RWTH Aachen University (ITA), Aachen and Markus Tutsch from STS Textiles GmbH & Co. KG, Grunbach, in their article in Technical Textiles. And complement them: In addition to intense physical exertion, an increased ambient temperature can lead to an increase in body temperature and thus to life-threatening heat shocks (from 40° C body temperature). This danger can and must be countered with the use of suitable protective clothing. It also shows the need to develop new materials.

A New Approach To Heat Protection

Within the framework of the research project "Development of heat-exposed occupational safety textiles", the focus is on the deeper layers of clothing. As a rule, conventional cotton underwear is used to absorb moisture, while the outer layers protect against heat radiation and burns. The cottonis in direct contact with the skin and can absorb and store large amounts of moisture due to its good absorption properties. The problem with this is that the stored moisture leads to a strong warming due to heating from the outside, which is not absorbed by protective clothing. This can actually lead to scalding and overheating due to the body's own perspiration.

The share of this heat damage in all accidents at work is about 50 percent for heat-exposed workplaces in Germany. The aim is to reduce this proportion to 10 percent by using 3D underwear.

Pressure-loaded areas in particular are reinforced locally in order to reliably prevent contact between the skin and the layer of protective clothing above it. In highly stressed areas such as knees, elbows or shoulders, local reinforcements must therefore be provided via stiffer pile threads that keep the needed distance. According to the current state of research, however, there is no possibility of changing the stiffness of the pile yarn during the production process.