Agglomerated materials based on residual leather from the footwear industry: Study of tensile absorption and shrinkage strength, (#1011)

Authors

Arévalo-Aranda, César

Olortiga Ortíz, Elva

Silva Aliaga, Rosa

Castillo Chung, Aldo

Albán Palacios, José

Vega Anticona, Alexander

Chávez Novoa, Danny

Abstract

In the present investigation, leather waste from the footwear manufacturing industry was used to make polymer-bound compounds. The objective of this work was to find the most appropriate leather and polymer mixtures that achieve the best physical-mechanical properties for possible use in applications in the leather-footwear sector. For this purpose, the effect of the type of binder polymer (polyester resin (RP), polyurethane (PU) and urea-formaldehyde (UF)) and the polymer/leather mass ratio (70/30; 80/20 and 90/10) on tensile strength, linear shrinkage and absorption were studied. In addition, the influence of the average leather particle size (0.840mm; 2mm and 4.76mm) and the leather/PU volume ratio (70/30, 80/20 and 90/10) on the tensile strength were studied. For the process of elaboration of study specimens with constant thickness, the manual hydraulic pressing method was used using an open steel mold and 8 tons of force. From the results obtained in the agglomerates with different polymers, it was determined that the PU allows obtaining the highest values of tensile strength, achieving a value of 9.5 MPa at a vol. ratio of 90/10 PU/leather. While the 70/30 UF/leather mix achieved the lowest tensile strength with a value of 1.7 MPa. Regarding moisture absorption, the highest value of 129% was obtained for the 70/30 UF/leather combination, while the minimum absorption of 5% was presented in the 90/10 PU/leather compound. For linear contraction, the lowest levels were obtained in the 70/30 PU/leather compound, while the highest values were identified in 90/10 RP/leather agglomerates. In the case of the agglomerated compounds of leather and PU, it was determined that for the 90/10 leather/PU ratio, the tensile strength tends to increase as the particle size becomes smaller. However, for the 70/30 and 80/20 ratios, the behavior is inverse, but the highest mechanical tensile strength (6.02 MPa) was obtained in test tubes with 70/30 leather/PU and 4.76 mm particle size of recycled leather.