Bulletin of
Vitebsk State
Technological
University

Abstract

Genuine leather is the best material for shoe upper due to its durability and high hygienic properties. Given the cost of genuine leather, synthetic leather is a cheaper alternative for shoe upper. However, the unique structure of synthetic leather, consisting of layers of various polymers, necessitates the development of shoe manufacturing technologies that take into account the properties of the upper materials. During shaping operations, the shoe upper is subjected to heat, which reduces tensile forces, increases the rate of relaxation processes, and increases the magnitude of residual elongation. An analysis of the literature revealed that the rheological properties of artificial leathers were studied mainly in earlier works, but the rheological properties of artificial collagen leathers were not studied, so such studies are relevant.

The aim of the work is to evaluate the relaxation indices of artificial collagen leathers used for the production of shoe upper under stretching and exposure to heat and to establish optimal heat treatment modes when performing shaping operations in the production of shoes upper made of such materials.

The experimental methodology involved deforming samples using an automated system capable of recording forces and calculating relaxation parameters. The thermal conditions applied to the samples corresponded to those used in artificial leather footwear manufacturing.

It has been determined that artificial leathers of the "Lac M1614" and "Marseille" product categories can be recommended for shoe upper, as their relaxation properties are comparable to those of genuine leather. The molding conditions for "Nubuck" artificial leather samples require optimization, as their relaxation properties are significantly lower than the recommended value (at least 45 %).

These results are of practical importance for determining molding conditions for artificial leather blanks during the design and engineering preparation stage.

The effect of heat treatment on the relaxation rates of artificial leather for shoe upper