DEPENDENCE OF THERMAL CONDUCTIVITY AND HEAT RETENTION ABILITY OF FABRICS FROM DIGITAL PRINT PARAMETERS

The human body transforms the chemical energy of the food into the work and the heat through the process of metabolism. The produced heat through the skin is transferred to the environment. In this case, in the state of thermal equilibrium, the amount of heat produced is equal to the amount of heat lost by conduction, convection, radiation, evaporation and breathing. The process of conduction of heat is transferred from the body to the environment, through layers of clothing and air, with the person standing still. Conductivity of heat in clothes depends on the thermal conductivity of the fibers from which the clothes are made, the conductivity of the air trapped in the pores of the clothes and the air on the surface of the clothing, the surface of the clothing layer through which the heat and the thickness of the clothes pass. The amount of heat transferred by conduction is usually negligible because the clothing, by its characteristics, slows down heat transfer in this way. Additionally, ink layers made in printing process significantly affect the properties of textile materials and clothes made from these materials. And today textile materials are increasingly being subjected to the process of printing due to aesthetic requirements of the people. This paper investigates the influence of digital printing parameters on the thermo-physiological features of textile materials. The essential print parameter was a different number of passes. In this research were used textile fabric materials of 100% cotton fibers. With printing process parameters, such as number of passes in the print, it is possible to influence the amount of ink that is applied on and in printed material, and thus the achievement of desired values of thermal parameters of printed materials. The influence of print parameters to thermo-physiological properties of the material is evaluated through a thermal conductivity and heat retention ability. Results of the research demonstrated that, in addition to material composition, the printing process with its parameters have a significant influence on the thermo-physiological characteristics of textile materials. The values of the thermal conductivity of the printed samples show that the increase in the number of application of ink in the printing results in a rise in the value of thermal conductivity coefficient, and decrease in heat retention ability value.