Articles publicats (Grup de Recerca A3 Leather Innovation Center)

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Open Access
Exploring the feasibility of substituting mimosa tannin for pine bark powder. A LCA perspective
(2022) Conde Mateos, Mireia; Combalia Cendra, Felip; Baquero Armans, Grau; Ollé i Otero, Lluís; Bacardit i Dalmases, Anna
The use of vegetable tannins is a bio-based alternative to chrome tanning. The most used vegetable extracts are Mimosa and Quebracho. To improve the sustainability of the tanning process, a chemically unmodified pine bark could be used as a natural source of tannins. The present study was aimed to evaluate the environmental impact of the use of pine bark powder to obtain vegetable leather through a life cycle assessment. Specifically, the life cycle impact evaluation was performed for both: i) pine bark powder tannin and the atomized mimosa extract production as raw material; and ii) the production process of a tanned leather with pine bark tannin versus a tanned leather with mimosa extract. An eco-friendly and cleaner production method for obtaining pine bark powder was developed. This new production method allows to obtain a reduction in 83% in the 'climate change' impact category. However, when this tannin is applied to obtain a tanned leather, the tanning process shows an increase in all studied impact categories compared with the use of the atomized mimosa extract.
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Analysis of the environmental impacts of waterproofing versus conventional vegetable tanning process - A life cycle analysis study
(Elsevier, 2021-10-11) Baquero Armans, Grau; Sorolla, Sílvia; Cuadros Domènech, Rosa; Ollé i Otero, Lluís; Bacardit i Dalmases, Anna; A3 Leather Innovation Center
Waterproofed vegetable leather is desired for its 'greenness' in front of chromium-tanned waterproofed leather. However, conferring waterproofing capabilities to vegetable tanned leather maintaining light color and a soft touch is a fact of great concern for leather goods producers. Sustainable and technical requirements are currently demanded by high-quality brands in order to pass the threshold established by Leather Working Group (LWG) initiatives to earn their environmental audit seal. The research work has focused on testing various mineral salts and hydrophobic products compatible with vegetable tanned leather. According to the obtained results, acrylic copolymers along with zirconium salts are necessary to achieve the desired leather properties. The present study provides the environmental comparison of a new vegetable tanning process to give waterproofing capabilities with the conventional vegetable tanning process. The comparison comprises both wastewater analysis and environmental impacts in a life cycle assessment (LCA) framework. The paper also outlines the comparison using different life cycle impact assessment (LCIA) methods. Further, the study provides specific data on leather vegetable tanning processes. Comparative analysis has been focused on the two diverging stages for both conventional and waterproofing vegetable tanning processes, namely retanning and fatliquoring. Conventional process environmental impacts are lower than waterproofing process impacts according to LCA methodology. However, wastewater analysis shows no major differences between both processes. Main contributors to these results are the zirconium salts, dispersing agents and acrylic copolymers used along with an increase in energy consumption due to processing times. Alternative methods used in the impact assessment lead to similar results, revealing no major differences in the comparative results between methods in this case.
Open Access
Study of the impact on occupational health of the use of polyaziridine in leather finishing compared with a new epoxy acrylic self-crosslinking polymer
(Elsevier, 2021-02-16) Ollé i Otero, Lluís; Frías Álvarez, Aroha; Sorolla, Sílvia; Cuadros Domènech, Rosa; Bacardit i Dalmases, Anna
The leather industry needs innovative products to meet the continued demands of the global market. To achieve a good performance in the finishing operation, crosslinking of the polymers used in this leather production stage is necessary. These crosslinkers are irritating and harmful. This study is based on the synthesis of functionalized acryl polymers with epoxy groups to improve the properties of the leather finishing to avoid the use of external crosslinkers, and consequently; harmful products for health and the environment will not be necessary. Likewise, the affectation in the health of workers exposed to crosslinker has been investigated when the leather finish is carried out. To do this research, a clinical analysis has been carried out prior authorization of the workers. The study demonstrates a good performance finishing avoiding the use of crosslinkers. In addition, it has been determined that molecular fragments of the decomposition of polyaziridine are present in the urine of one of the employees. Although the human metabolism may metabolize these polyaziridine fragments being non detectable in the urine samples, a positive result was obtained in the analysis by GC-MSD of the urine, and therefore; it could affect the health of this employee.
Open Access
Evaluation of a new sustainable continuous system for processing bovine leather
(Elsevier, 2015-08) Bacardit i Dalmases, Anna; Baquero Armans, Grau; Sorolla, Sílvia; Ollé i Otero, Lluís
The aim of the present work is to evaluate a new sustainable continuous system for processing bovine leather. By means of a prototype described in the international patent WO, 2010/070571 (A2) of the technological centre AIICA, a dehydration process for bovine hides is carried out. What is obtained through this new process is a dehydrated leather with the optimal physical and chemical characteristics that will allow its subsequent tanning by immersion processes in aqueous solutions of chemical products. When compared to existing traditional processes, there are economic and environmental advantages resulting from the use of this new system. More specifically, the new process results in reductions of 30.6% in water use, 50.2% in chemical use and 16.4% in process time. In addition, a reduction of 27.3% in wastewater and a reduction of 47.5% of thermal energy consumption are obtained. However, this new system presents an increase in electricity consumption of 63.03% and an increase in gaseous emissions of 75% due to the use of acetone in the dehydration process and the 0.5% losses of acetone during the process. In order to better assess the environmental impact of this new tanning system, life cycle analysis methodology has been chosen to perform calculations on the Global Warming Potential (CO2 equivalent emissions) and the energy consumption comparing both traditional and new tanning processes.
Open Access
Formaldehyde scavengers for cleaner production: A case study focused on the leather industry
(Elsevier, 2018-06) Marsal Monge, Agustí; Cuadros Domènech, Sara; Ollé i Otero, Lluís; Bacardit i Dalmases, Anna; Manich i Bou, Albert Mª; Font Vallès, Joaquim
Due to its carcinogenic character, the presence of formaldehyde in leather continues to be a subject of great concern. By using formaldehyde scavengers, it is possible to reduce the formaldehyde content in leather. In this work, the potential ability of three different compounds (ethylene urea, pyrogallol and gallic acid) to reduce the formaldehyde content in splits leathers treated with formaldehyde resins (melamine-formaldehyde and dicyandiamide-formaldehyde) is assessed. This capacity is compared with that of a fourth scavenger (hydroxylamine sulphate) already used in tanneries. The evolution of the formaldehyde content with time is also considered, as well as the potential coadjuvant effect of other compounds such as mimosa extract and an acid dye (Acid Black 234). Hydroxylamine sulphate initially showed the highest ability to reduce formaldehyde content. However, after a certain time, this ability proved to be inferior to the ability of other compounds due to the reversibility of the reaction between hydroxylamine and formaldehyde. Pyrogallol showed a higher ability than gallic acid when used in the final wash of leather processing. However, the treatment with pyrogallol results in a darkening of the leather; this darkening limits its use. Gallic acid may be a good alternative to formic acid as the final fixing agent in leather processing when the presence of formaldehyde in leathers is suspected. The use of gallic acid in the final wash or as a fixing agent fulfils the formaldehyde content limit (65–75 mg/kg) of the major brands in leather goods in direct contact with the skin. The addition of 2% of gallic acid in the final wash of leather processing resulted in formaldehyde content reductions that varied from 65% to 85%. However, further experiments are required to assess the influence of gallic acid on the fastness properties and the coloration acquired by the treated leathers. The joint effect of gallic acid in the final wash or as a fixing agent and mimosa extract as a retanning agent in formaldehyde content reduction is even enhanced by subsequently using a dye with amino groups in its chemical structure. Reducing the formaldehyde content by using scavengers can contribute to the achievement of a cleaner production in those sectors (leather, textile, wood) that use formaldehyde resins.

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