## 4 Discussion  
The results of the present study on the thermal conductivity of complex materials with different fractions of the Outlast textile in combination with the Termofiber showed a general increase in conductivity with an increasing fraction of the Outlast textile in the complex material. This can be explained by the material's own high thermal conductivity of the active component of the paraffin-based capsules. It was found that for similar complex materials at temperature conditions of +25 \({}^{\circ}\)C and +5 \({}^{\circ}\)C, the thermal conductivity differed by up to 10%, mainly in the downward direction at a reduced temperature regime. However, the thermal conductivity of samples for different temperature conditions showed that after reaching the Outlast textile fraction in the composite material of more than 50%, the thermal conductivity at elevated ambient temperatures (+25 \({}^{\circ}\)C) tends to decrease, thus improving the thermal insulation of the clothing. This feature of the materials is of interest for the use of composite fiber material for protection from high temperatures. At the same time, for low temperatures (+5 \({}^{\circ}\)C), the same composition of materials retains the dynamics of increasing thermal conductivity with an increase in the fraction of the Outlast textile and the microcapsulated paraffin, respectively. With a significant increase in the thermal conductivity of the insulation material, an increase in the overall thickness of the clothing materials is required to provide sufficient thermal insulation from the cold. However, from the point of view of the criteria of clothing ergonomics, there are restrictions on the maximum total thickness of clothing (no more than 4 cm) and the corresponding thermal characteristics of textile shells (thermal resistance, no less than 0.77 m\({}^{2}\)K/W; thermal conductivity, no more than 0.052 W/mK) [37; 38].  
The thermal resistance of the shell materials is calculated using the Formula (1):  
\[\mathrm{R=d/\lambda}, \tag{1}\]  
where R is the thermal resistance in m\({}^{2}\)K/W; d is the thickness of the fabric in m; and \(\lambda\) is the thermal conductivity in W/mK.  
Figure 7: Thermal conductivity of the complex material Termofiber/Outlast textile depending on the proportion of the heat-accumulating textile component and the temperature.  
The range of the thermal conductivity data obtained for a complex material has acceptable values within 85% of the Outlast textile fraction in the total material composition. However, to meet the requirements mentioned above, it is necessary to apply the criterion of reducing the thermal conductivity of the clothing materials, which should be limited to no more than 0.045 W/mK. Based on the obtained research results (Figure 6), for the development of complex materials from Termofiber + Outlast textile, the fraction of the Outlast textile component should be limited to no more than 40% for textile shells in clothing operated at a temperature of +5 \({}^{\circ}\)C or below. Further conditions for determining the composition of the studied materials for clothing can be settled by taking into account the density of materials, the mass, and the general thermal insulation of clothing.