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B2B Журнал
19.04.2017 | Лидия Соколова

Dry means comfortable

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In this sense, it is very interesting that chemical fibers are used for the production of high-quality synthetic insulation, including periodically having a hollow "air" structure, which provides not only the heat-saving properties of canvases and slabs, but also enhances the range of operational qualities. Multichannel fiber cavities without the effect of capillarity have the properties of increased thermal insulation, confirming the well-known fact that air is the best heat insulator.

 

Thus, periodically hollow air areas in the fiber of nonwovens are a huge number of additional, hermetically sealed thermally air layers or layers that do not absorb or retain moisture, which reduce thermal conductivity and increase thermal protection.

So, the most important and simplest characteristic of the heat-protective properties of ready-made clothing is thermal resistance, that is, the inverse of thermal conductivity. Thermal resistance is due to the thickness of the air layers, the fibrous composition of materials, and the number of layers. This whole "pie" either absorbs and retains moisture, or it doesn't. The effectiveness of the insulation depends on this.

 

 

An increase in the humidity of the package leads to a sharp decrease in its air permeability. And this is a global problem of moisture-absorbing insulation. The fact is that clothes should be breathable, which is necessary to maintain the thermal balance of the body with the external environment, the flow of fresh air to the body and the removal of carbon dioxide from the underground space. Excessive amount of carbon dioxide negatively affects the well-being and performance of a person. Insulated workwear with carbon dioxide retained in the insulation layer becomes a "cellophane punishment cell" for the employee.

 

Another problem that results from high hygroscopicity is electrical conductivity. With increasing humidity, the electrical conductivity increases. When mechanical influences on synthetic insulation (for example, the operation of workwear), electrostatic charges occur. They can be extremely dangerous in cases where the insulation itself contains a large amount of microflags.

 

Hygroscopicity also significantly affects the absorption of foreign odors (sweat, various oils, etc.). In the process of wearing clothes, they become dirty, absorb secretions of sweat and sebaceous glands. This contributes to the development of dangerous microflora. It is desirable that clothing insulation materials have antimicrobial properties or properties that limit the spread of parasites. Therefore, by the way, recently insulation materials with additives (wool, algae, bamboo, oches, defects of textile industries, etc.) simply do not meet sanitary and microbiological requirements. When cleaning from dirt, clothes are not completely free of microorganisms, so they must be resistant to various types of treatment (washing and ironing at high temperature, the use of disinfectants) and do not absorb / retain moisture. This is not possible for all insulation materials.

 

Zero hygroscopicity of modern synthetic insulation allows it to maintain plasticity, not to be brittle even at critically low temperatures, marked in the harshest climatic points.

 

Textile experts note that less moisture absorption also contributes to better preservation of the shape and silhouette of the garment, reducing its deformation (the effect of wet fibers sticking together has already been noted above). Waterlogging of the insulation not only increases heat loss, but is often the cause of severe creasing (depending on the degree of swelling of the moisture-absorbing fiber), damage to the fabric and the entire product, as well as fungal infection, corrosion of metal fittings.

 

As you know, the liquid state is usually considered intermediate between a solid and a gas: a gas retains neither volume nor shape, and a solid retains both. At critically low temperatures (­–30–45 ºC), at which specialists of the IV climatic zone perform production tasks, the transition of the liquid held in a hygroscopic synthetic insulation from a gaseous-liquid state to a solid is obvious. How does this turn out? Unambiguously, the loss of heat-protective properties, a decrease in elasticity (such clothes simply "oakens", restricts and restricts movement).

 

The weight of a set of winter clothes is sometimes an eighth to a tenth of the body weight, which causes additional energy costs when wearing, so it is necessary to use lighter basic, auxiliary and insulating materials. And, of course, non-hygroscopic, since only the weight of the absorbed moisture can be more than 1 kg in special clothing (jacket + overalls).

 

 

To date, the whole world uses advanced scientific and technical developments in the field of insulated clothing, including high-tech insulation with low hygroscopicity. In fact, it is this indicator that directly or indirectly affects the whole chain of operational properties and qualities of insulating materials. Advanced developments are associated with the use of high-tech synthetic insulation materials, which are not only not inferior, but also in a number of positions surpass natural ones in their physical and mechanical characteristics. NATO countries use them in insulated military uniforms. Leading oil companies for the work of their employees in the northern regions use synthetic insulation in the manufacture of workwear.

 

In the National Standard "Special clothing for protection against low temperatures", the requirements for insulation were fairly reduced to "Requirements for lining fabrics". That is, the main "hygroscopic function" is assigned to the lining of insulated workwear. It is the woven lining and the fabric of the top that should, respectively, absorb and remove (due to the convection air-conducting properties) excess moisture, ensure the preservation of warm air in an absolutely dry insulation to obtain the maximum heat-saving effect.

 

So, the insulation should not be hygroscopic. It should be dry, and then it will be warm. Moisture from the undercover air should not be absorbed and retained in the insulation, but removed. It is for this purpose that modern and well-proven insulation materials are created.

Ending.

 

Author: Vladislav Ivanov,

& nbsp;         Director of  plant development «Thermopol», (TM "Holofiber").

Photo: Shutterstock.com 

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