Clothing protects a person not only from high or low temperature and precipitation, but also from solar radiation, wind and mechanical damage. The surface of the skin must be hidden from these effects, as well as from dust, dirt and pathogens. The material must not contain harmful chemical compounds or other impurities. There are special characteristics of tissues that determine their properties and ability to perform certain functions. It can be heat-shielding properties, the ability to absorb dust and dirt, protection from chemical compounds and insect bites. Such characteristics are called the hygienic properties of tissues.
What property of tissue is called hygienic
There are several properties of the material related to hygiene:
- hygroscopicity;
- wetness;
- dust extraction;
- sorption properties;
- heat-shielding properties;
- lack of harmful impurities;
- capillarity;
- water absorption;
- water resistance;
- breathability;
- vapor permeability.
What is tissue hygroscopicity
Hygroscopicity is the ability of a material to absorb moisture from the atmosphere. This is an unstable indicator, but one of the most important. Hygroscopicity varies with temperature and humidity. If such changes did not occur, then this property would not matter. The hygroscopicity parameter determines how well the tissue regulates heat transfer between the human body and its environment. The process of moisture absorption by a material largely depends on air humidity and season. Indoors, the air is usually drier than outdoors, which is why this figure will be lower in the first case.
In the process of condensation of water vapor, a certain amount of heat is always generated, which must be compensated if a person leaves a closed room and goes into fresh air. At the same time, such an amount of heat is released that under normal conditions the body consumes for several hours. This does not happen overnight, but gradually. The ability to absorb moisture depends on the composition of the material, its structure, fibers and other qualities of the cloth. There are special tables of the properties of fabrics, which determine the difference between a particular material. Among them, hygroscopicity is usually present.
Fabric wetness
Also, wetness is related to the hygienic properties of fabrics. Hygroscopicity refers to the absorption of vapors, and wetness refers to the absorption of liquids. This property is especially important for the materials from which towels, shirts, sheets and other products are made. Additional wetting characteristics are capillarity and water absorption. The first property is determined by a strip of fabric dipped on one side in a special mixture consisting of a crystallizer and a solution of eosin in alcohol. The second - by soaking the sample in water for 1 minute. Sufficient wetting of the fabric corresponds to 100% absorption of moisture and capillarity in the range of 100-400 mm.
Table of properties of cotton and linen fabrics: physical, mechanical, hygienic, technological
When comparing tissues, their qualities are revealed.
| Fabric properties | Cotton fabrics | Linen fabric |
| Strength | Less durable than linen | Durable |
| Creasing | Crumpled | Heavily crushed |
| Hygroscopicity | High | Higher than cotton |
| Thermal properties | Medium | The weak |
| Shedding threads | Weak | Average |
| Shrinkage | Significant | Significant |
Water-resistant and waterproof fabrics
Hygienic properties of fabrics also include water resistance - the ability of a fabric to resist getting wet. This is achieved by applying a special coating to the surface that interferes with the penetration of water. Water resistance does not affect air permeability, because the pores of the material do not clog and continue to allow water vapor and gases to pass through.
Water-repellent fabric is not equal to waterproof. In this case, the pores in the cloth are filled with a substance forming a thin protective film that does not allow steam and moisture to penetrate through the surface of the material. This adversely affects the hygienic properties of tissues. Water-repellent fabric is most often used for sewing raincoats, jackets, making umbrellas, in woolen and costume materials. The ability to not pass water is of great importance for tent fabrics and tarpaulins. In the tables “Fabric properties” this parameter is usually present, by which it is possible to determine whether the material can be used for special products.
Breathability of fabric
Breathability is an important characteristic of fabrics, expressed in their ability to pass air and ensure that clothes will be well ventilated while maintaining a certain ratio of humidity and gas composition of the air gap under the material. Carbon dioxide tends to accumulate in the space under clothing. Its concentration in this case doubles, compared with ordinary air. If the content of this substance in the space under clothing is 0.1%, fainting may occur. A person begins to quickly become tired and feel very tired. Therefore, it is so important that the fabric is well ventilated and its structure is porous.
What is vapor permeability, radiation permeability and dust absorption
Hygienic properties of fabrics also include vapor permeability and radiation permeability. Vapor permeability is the ability of a material to pass water vapor, which is constantly formed on the skin as a result of perspiration. Under normal conditions, the human body can emit about 1 liter of vapor, but under intense load, this amount can increase by 12 times. This property of the fabric is calculated based on the amount of water vapor passing through the material in 1 hour. This characteristic is of particular importance for cloth, from which bed linen, dresses and blouses, men's suits and linings are made.
Hygienic properties of the fabric include radiation permeability and heat protection. Permeability is a property of the fabric, determined by the amount of ultraviolet rays that transmits the surface of the material. A certain amount of rays is necessary for the human body to function properly. But they are able to penetrate under matter, be reflected by it and absorbed. These properties depend on the composition of the cloth, its finish and structure.
Thermal protection is of the greatest importance for the fabrics of which warm clothing is made. Heat transfer between the human body and the environment is a complex process, it involves many factors that influence the choice of the suitable material.