Sustainable Reactive Polyurethane Hot Melt Adhesives Based on Vegetable Polyols for Footwear Industry

The aim of this work is to develop sustainable reactive polyurethane hot melt adhesives (HMPUR) for footwear applications based on biobased polyols as renewable resources, where ma-croglycol mixtures of polyadipate of 1,4-butanediol, polypropylene and different biobased polyols were employed and further reacted with 4-4′-diphenylmethane diisocyanate. The different reactive polyurethane hot melt adhesives obtained were characterized with different experimental techniques, such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), softening temperature and melting viscosity. Finally, their adhesion properties were measured from T-peel tests on leather/HMPUR adhesives/SBR rubber joints in order to establish the viability of the used biobased polyols and the amount of these polyols that could be added to reactive polyurethane hot melt adhesives satisfactorily to meet the quality requirements of footwear joints. All biobased polyols and percentages added to the polyurethane adhesive formulations successfully met the quality requirements of footwear, being comparable to traditional adhesives currently used in footwear joints in terms of final strength. Therefore, these new sustainable polyurethane adhesives can be considered as suitable and sustainable alternatives to the adhesives commonly used in footwear joints.

An integrated AHP-TOPSIS framework for determination of leading industrial sectors

This study aims to determine the leading industry in Padang Pariaman Regency, West Sumatera, Indonesia, based on data from the Central Statistics Agency and expert opinion on the Regency Industrial Development Plan. This research combines qualitative and quantitative techniques. This study uses four experts' opinions consisting of three governments and one academician. The criteria and sub-criteria are determined based on the locally adapted National Industrial Development Master Plan. The method used in this study is a combination of the Multi-Criteria Decision Making (MCDM) method, which integrates the Analytical Hierarchy Process (AHP) to calculate the weights and the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) to determine the order of priority. The top five leading processing industries were selected: the food industry, the leather/footwear industry, the chemical industry, the apparel industry, and other processing industries.

Simultaneous Sonochemical Coloration and Antibacterial Functionalization of Leather with Selenium Nanoparticles (SeNPs)

The development of antibacterial coatings for footwear components is of great interest both from an industry and consumer point of view. In this work, the leather material was developed taking advantage of the intrinsic antibacterial activity and coloring ability of selenium nanoparticles (SeNPs). The SeNPs were synthesized and implemented into the leather surface by using ultrasonic techniques to obtain simultaneous coloring and functionalization. The formation of SeNPs in the solutions was evaluated using UV/Vis spectroscopy and the morphology of the NPs was determined by transmission electron microscopy (TEM). The treated leather material (leather/SeNPs) was characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The effects of SeNPs on the coloration and antibacterial properties of the leather material were evaluated. The results revealed that the NPs were mostly spherical in shape, regularly distributed, and closely anchored to the leather surface. The particle size distribution of SeNPs at concentrations of 25 mM and 50 mM was in the range of 36–77 nm and 41–149 nm, respectively. It was observed that leather/SeNPs exhibited a higher depth of shade compared to untreated ones, as well as excellent fastness properties. The results showed that leather/SeNPs can significantly enhance the antibacterial activity against model of bacteria, including Gram-positive bacteria (Bacillus cereus) and Gram-negative bacteria (Pseudomonas aeruginosa, Salmonella typhi and Escherichia coli). Moreover, the resulting leather exhibited low cytotoxicity against HFB4 cell lines. This achievement should be quite appealing to the footwear industry as a way to prevent the spread of bacterial infection promoted by humidity, poor breathability and temperature which promote the expansion of the microflora of the skin.

Assessment of the influence of psychosocial factors on musculoskeletal disorder symptom intensity

BACKGROUND: Previous studies have observed that psychosocial factors are associated with an increase in work-related musculoskeletal disorders (WMSDs) in European countries. However, the influence of psychosocial factors on the WMSD symptoms has not been studied in detail. Additionally, working conditions differ between developing and developed countries. OBJECTIVE: In this study, the influence of psychosocial factors on WMSD symptoms among men and women in the footwear industry in northeastern Brazil is investigated. METHODS: A questionnaire survey was conducted to evaluate workers’ perceptions of psychosocial factors and WMSD symptoms. The influence of psychosocial factors on WMSD symptom trends was observed through ordinal logistic regression models. RESULTS: It was found that different psychosocial factors are related to WMSD symptom intensification. Factors such as “job insecurity” and “low social support,” which are not associated with the worsening of WMSD symptoms in developed countries, showed a noticeable influence in the sample analyzed. CONCLUSION: These findings may be associated with differences in working conditions and economic problems in developing countries, suggesting that some psychosocial factors have a different effect on workers’ perceptions in developing countries.

Assessing the Compressive and Impact Behavior of Plastic Safety Toe Caps through Computational Modelling

Toe caps are one of the most important components in safety footwear, but have a significant contribution to the weight of the shoe. Efforts have been made to replace steel toe caps by polymeric ones, since they are lighter, insulated and insensitive to magnetic fields. Nevertheless, polymeric solutions require larger volumes, which has a negative impact on the shoe’s aesthetics. Therefore, safety footwear manufacturers are pursuing the development of an easy, low-cost and reliable solution to optimize this component. In this work, a solid mechanics toolbox built in the open-source computational library, OpenFOAM®, was used to simulate two laboratory standard tests (15 kN compression and 200 J impact tests). To model the polymeric material behavior, a neo-Hookean hyper-elasto-plastic material law with J2 plastic criteria was employed. A commercially available plastic toe cap was characterized, and the collected data was used for assessment purposes. Close agreements, between experimental and simulated values, were achieved for both tests, with an approximate error of 5.4% and 6.8% for the displacement value in compression and impact test simulations, respectively. The results clearly demonstrate that the employed open-source finite volume computational models offer reliable results and can support the design of toe caps for the R&D footwear industry.

Influence of biobased polyol type on the properties of polyurethane hotmelt adhesives for footwear joints

Polyurethanes, one of the most used polymers worldwide, are strongly dependent of non-renewable fossil resources. Thus, boosting the production of new polyurethanes based on more sustainable raw materials is crucial to move towards the footwear industry decarbonisation. The aim of this study is to synthesise and characterise reactive hotmelt polyurethanes from biomass and CO2-based polyols as bioadhesives for the footwear industry. The influence of biobased polyols on the polyurethane structure, and therefore, on their final properties was analysed by different experimental techniques such us Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), Melting viscosity, Softening temperature and T-peel strength test, in order to assess their viability for the upper to sole bonding process. The results obtained indicated that the incorporation of different amounts of the biobased polyols produces changes in the structure and final performance of the polyurethanes. Therefore, adhesion test carried out by the T-peel test 72 h after the upper -to- sole bonding of the sustainable adhesives show high final adhesion values. These sustainable raw materials provide polyurethane adhesives with additional beneficial non-toxicity and sustainable characteristics, without harming their properties during their useful life.

O uso do cartão de crédito: o valor da marca e materialismo influenciam no comportamento impulsivo de compra?

Purpose - This study aims to identify factors, such as materialism and brand equity, that can influence impulsive buying behavior associated with the use of a credit card.Design/methodology/approach - We adopted the survey method, collecting 384 structured face-to-face questionnaires, focusing on the footwear industry. We collected the data in the state of Rio Grande do Sul - Brazil, covering the seven mesoregions of the state. Confirmatory factor analysis, descriptive statistics, ANOVA, T test and Structural Equation Modeling (SEM) were used to analyze the data.Findings – In this study, we find that brand equity does not impact impulsive buying behavior, but the credit card positively impacts impulsive buying behavior.Research limitations/implications – The research was executed just in one province, so future research could be developed in other’s places and culturesPractical Implications – This study can help scholars and managers of footwear industry understand impulsive buying behavior of its consumers.Original value – This study shows the relationship between credit card use, materialism and impulsive buying behavior constructs.