Characteristics of polyurethane and elastomer parts for shoe industry produced by liquid injection molding technology

Karkalić, Radovan; Radulović, Jovan; Jovanović, Dalibor

doi:10.5937/vojtehg65-10543

Cited by 15 publications

(4 citation statements)

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“…All the shoes had visually varying tread patterns with a similar outsole material (i.e., polyurethane). Polyurethane (PU) is a widely used material to develop shoe outsoles for formal shoes due to its durability and ease in distribution of plantar pressure [29][30][31]. Cuticles are a distinctive feature of PU.…”

Section: Replication and Fabrication Of Footwear Outsolesmentioning

confidence: 99%

Frictional Characteristics of Progressively Worn Footwear Outsoles on Slippery Surfaces

Gupta,

Chatterjee,

Chanda

2023

Tribol. Ind.

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Slip and fall related injuries are common in workplaces and sufficient shoe-floor friction is required to prevent such incidents. Besides the presence of slippery contaminants, shoe wearing over time is one of the key factors which may lead to significant reduction in shoe-floor friction. While footwear-based slip testing has been conducted widely across floorings and contaminants, limited studies have focused on the effect of worn shoes on slipping. In this work, twelve formal shoes from common brands were tested through modelling of their outsoles in normal and different degrees of progressively worn conditions. Mechanical slip testing was conducted to quantify the available coefficient of friction (ACOF) of the outsole models across dry and two common contaminant conditions (i.e., floor or surface cleaner, and canola oil), and on three commonly available floorings. The effect of flooring, contaminant, and worn area, on the ACOF were characterized extensively. Progressively worn outsoles were found to lead to reduction in ACOF in the range of 28-97%. Outsoles having tread channels oriented at different angles with respect to the direction of footwear motion, were found to generate higher ACOF, than ones with horizontal tread patterns. Outsoles which had larger treads but with lesser intervals (i.e., large tread surface area) showed lower ACOF values. These outsoles experienced less reduction in the ACOF in the following cycles of wear. For safety against slips, outcomes from this work are expected to provide essential information for buying or replacing the formal shoes in its new or worn condition.

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Section: Replication and Fabrication Of Footwear Outsolesmentioning

confidence: 99%

Frictional Characteristics of Progressively Worn Footwear Outsoles on Slippery Surfaces

Gupta,

Chatterjee,

Chanda

2023

Tribol. Ind.

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“…Una razón importante de la obtención de una menor resistencia mecánica alcanzada en los aglomerantes con RP y con UF es por la fragilización que pudo haber generado microgrietas y/o tensiones residuales que resultaron durante la polimerización en cada uno de estos polímeros tal y como la reporta Richardson& Lokensgard (2000) en la que estos polímeros tienen una baja energía de impacto Izod como el caso el caso específico de UF que comprende valores de 0.0125 J/mm -0.13 J/mm en comparación con la del PU que tiene una energía de impacto izod mayor a 0.25 J/mm. La resistencia para el PU usado para suelas exteriores de calzado usualmente recae entre 10 MPa -15 MPa [16,17]; con ello se puede decir que el mayor valor de resistencia alcanzada de 9.5MPa en este trabajo con PU/cuero a 90/10 resulta tener un valor que se aproxima al mínimo requerido para suelas de calzado que requiere que tenga un mínimo de 12 MPa para ser empleado como suelas exteriores [17]. A pesar que este valor de resistencia mecánica mayor alcanzada en este trabajo no sería tan apropiado para suela exterior, si podría ser empleada para plantillas de montaje, falsas y protección de membranas porque estarían incorporadas en la parte intermedia y no requieren las propiedades de aquellas expuesta hacia el exterior al contacto con el piso.…”

Section: Ensayo De Tracciónunclassified

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

Arévalo-Aranda¹,

Ortíz²,

Aliaga³

et al. 2023

Proceedings of the 21th LACCEI International Multi-Conference for Engineering, Education and Technology (LACCEI 2023): “Leaders

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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.

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“…Footwear industries mainly use PU in the form of cross-linked microcellular foams for the production of soles for shoes and chappals. 2 Thermoset PU is produced in footwear industries by the copolymerization reaction between butane-1,4-diol and diphenylmethane 4,4'-diisocyante. This PU along with coloring agents is passed to the mold for the production of shoe sole with desired shape.…”

Section: Introductionmentioning

confidence: 99%

Reutilization of polyurethane-based shoe sole scrap as a reinforcing filler in natural rubber for the development of high-performance composites

Bashpa¹,

Bijudas²,

Dileep³

et al. 2022

Journal of Elastomers & Plastics

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Reutilization of industrial waste is one of the emerging strategies to combat solid waste disposal for the protection of our environment. The present work describes a novel and economic approach to reutilize finely ground shoe sole scrap, a thermoset polyurethane-based waste (PUW) material generated during shoe sole production in footwear industries as an efficient reinforcing filler in natural rubber (NR). Shoe sole scrap was ground to fine powder and characterized by various analytical techniques. NR-PUW composites were prepared using 0–20 phr (parts per hundred of rubber) of PUW. The cure characteristics, mechanical, thermal, and morphological properties of prepared composites were studied. Composite with 5 phr PUW showed a remarkable improvement in tensile strength by 10% and modulus at 300% elongation increased by 9% compared to that of neat sample. A considerable increase in abrasion resistance and tear strength was also observed in 5 phr PUW loaded composites. Other mechanical properties like hardness, heat build-up and compression set showed a regular increase with further filler loading. To estimate the level of interfacial adhesion between the filler and the matrix, the experimental values of tensile strength were compared with Nicolais–Narkis (N–N), Lu, and Turcsányi–Pukànszky–Tüdõs (T–P–T) models and elastic modulus values with Einstein and Guth and Smallwood models. The tensile strength values are in agreement with T-P-T model (B = 4), up to 5 phr PUW proving the better adhesion between NR and PUW at lower filler loadings. At higher PUW loading, the experimental results are approaching Lu and N–N models indicating that this adhesion is collapsed. The incorporation of PUW as a filler in NR does not adversely impact the thermal stability of prepared composites. The results obtained are not only promising from a circular economy perspective, but also is contributive in production of high-performance, low-cost NR composites for various industrial applications.

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Characteristics of polyurethane and elastomer parts for shoe industry produced by liquid injection molding technology

Cited by 15 publications

References 0 publications

Frictional Characteristics of Progressively Worn Footwear Outsoles on Slippery Surfaces

Frictional Characteristics of Progressively Worn Footwear Outsoles on Slippery Surfaces

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

Reutilization of polyurethane-based shoe sole scrap as a reinforcing filler in natural rubber for the development of high-performance composites

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