Clothing Comfort and Body Microclimate

One of the main purposes of the use of textile technology is to conduct systematic functional apparel design so that clothes can do its best to help people regulate body temperature and environmental temperature as well as human physical activity. The key to the technology lies in the properties of heat resistance and humidity control of textile materials. That is: the ability of clothing to absorb sweat from the body's surface.

Sweating is the most effective way to keep the body cool. It drains sweat by consuming energy, that is, removing heat from the surface of the skin. Every kilogram of sweat evaporated by the body consumes about 580 kcal, which is equivalent to the calories burned for an hour of intense physical training, or the calories burned in a fast food meal. At the same time, when the outside temperature is higher than body temperature, perspiration is also the only way to reduce heat. Of course, the most effective method is to remove sweat directly through the skin.

In general, the function of releasing sweat through the surface of textiles in the form of water vapor is called breathability. However, the exchange of breathability (or water vapour resistance) in academic terms with our usual breathability is incorrect, because low air permeability does not lead to low permeability. The best example is the modern windproof waterproof membrane. This membrane allows very little air to penetrate from the outside to the inside of the membrane and also allows perspiration to evaporate from inside to outside.

However, breathability is only one aspect of warmth and humidity regulation, the so-called thermophysiological characteristics. It is also important that if enough sweat is absorbed, stored and released, it will make the wearer feel that: This is simply a kind of skin enjoyment.

Thermo-physiological comfort and skin contact comfort (ie how the skin feels on textiles) can be measured objectively and evaluated in the laboratory. The Hohenstein Institute in Germany has been working on the development of related textile functional testing methods since the 1950s. Many methods are still used worldwide.

One of the most important is to have the skin model simulate the release of heat and moisture from the skin's surface. The model consists of a porous metal plate that can be heated electrically to the skin and a device that supplies water. The model is placed in an artificial climate chamber to maintain constant measurement conditions.

The specific parameters provided by the skin model were used to measure the performance of the textile. For example, warmth and water resistance are used as reference conditions to measure the breathability, perspiration function and cushioning of fabrics, and the length of time needed to dry a garment. These parameters represent the thermal physiology of the textile.

The Hohenstein Institute in Germany called the two human models “Charlie” and “Sharin”. Through their in-depth study, the warmth of clothing, bedding and sleeping bags can all be calculated. Using a thermoregulation model, you can simulate the heat produced by adults and children. The model is made of copper or synthetic material with a computer-controlled heating system installed to control the heat generated by different parts of the body. For example, the more heat emitted from the arms or legs, the worse the warming effect of the corresponding parts of the clothes.

When the body is moving, body temperature is significantly affected by the permeability of the Fabric. For example, the breathability of cuffs or other parts. This is why during the clothing test, "Charlie" was placed in the stands to simulate how he seemed to walk. The use of mannequins can be used to evaluate the regulation of the humidity of textiles. This is an important measure to improve the function of textiles.

In the "sweat-foot" thermal regulation model, the Hohenstein College's skin models and mannequins play an important role. And the two are combined into one. The pattern of moisture and heat released by it is a typical foot shape.

As a result, researchers at the Hohenstein Institute believe that using human models to simulate body temperature in limbs is feasible. What's more, they found that when the ambient temperature is low, most of the heat is mainly emitted from the toes. In other words, warm shoes and socks play a great role in maintaining the overall body comfort and body surface temperature. At the same time, the treated textile material should be able to absorb human sweat, especially after people exercise, the textile can effectively absorb the sweat secreted by the body.

In the 1930s, the development of the first synthetic textile fibers “nylon” and “perlon” marked the beginning of a new era in the textile industry. In addition to traditional natural fibers, for the first time, mankind has textiles that can artificially change its attributes. Of course, in the 1960s, a so-called imitation nylon shirt made synthetic fibers left a bad impression on the public. However, in the following years, the Hohenstein Institute's experiments showed that if properly designed, textiles made of synthetic fibers not only have the same warmth and humidity control functions as natural fibers, but even have advantages over natural fibers.

From the 1980s onwards, on the basis of Hohenstein's research, double-sided fabrics came out. This cloth combines natural fibers with synthetic fibers but is still stored separately. When these two materials are combined, comfort is much greater than that of cotton because it does not stick to the skin. At the Winter Olympic Games in Lake Placid in 1980, a sportswear manufacturer sponsored a double-layer underwear for an Austrian women's team. Later, this underwear was named after the name "Transtex" and was subsequently widely used by athletes. use. In the manufacturer's expectation, this underwear has been a great success. Since then, functional textiles have been singing all the way, and the difference in comfort between clothing has increased. (China Fiber Inspection)