Articles publicats (Grup de Recerca A3 Leather Innovation Center)

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Open Access
Determinación de pesos moleculares de los ácidos húmicos por crioscopía en fase estacionaria
(Asociación Química Española de la Industria del Cuero, 2013) Bacardit i Dalmases, Anna; Jorge Sánchez, Joan; Bou Serra, Jorge; Ollé i Otero, Lluís
En este trabajo se estudian los pesos moleculares de los ácidos húmicos para determinar su capacidad para penetrar dentro de la piel y su posterior unión química entre fibras. La determinación del peso molecular se ha realizado por crioscopía en fase estacionaria en atmósfera de nitrógeno. Según el estudio realizado, los ácidos húmicos naturales son los que presentan un peso molecular más pequeño. Los ácidos húmicos regenerados y los sulfonados presentan un peso molecular más elevado per aún suficiente para poder penetrar entre las fibras de colágeno.
Open Access
Aplicación de taninos sostenibles con baja huella de carbono
(Asociación Química Española de la Industria del Cuero, 2014) Díaz, Jorge; Casas, Concepció; Sorolla, Sílvia; Mir, Teresa; Ollé i Otero, Lluís; Bacardit i Dalmases, Anna
Hoy estamos viviendo un "boom ecológico", lo que significa el desarrollo de procesos con un menor impacto ambiental, haciéndolos lo más ecológico posible. Esa es la razón de llevar a cabo este trabajo, tratar de utilizar un extracto vegetal como fuente sostenible para el proceso de curtido. Considerar el fruto del árbol de Tara como una materia prima con baja huella de carbono como agente de curtido y proponer alternativas para evitar el uso de otros extractos vegetales comerciales y sales minerales. Se han desarrollado diseños para adaptar un nuevo tanino de Tara por modificación química y física, con el fin de obtener un porcentaje más alto de taninos y aumentar su grado de penetración en la piel. En la modificación física, la Tara se ha molturado y tamizado, en varios tamaños de partícula, con el fin de obtener un tamaño molecular más pequeño. Las modificaciones se probaron en la piel, en un proceso de precurtido wet-white, combinándolos con la menor cantidad posible de extractos vegetales comerciales y sintéticos. Las formulaciones se han optimizado utilizando un diseño experimental.
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
Desarrollo de productos a partir de Caesalpinia spinosa
(Asociación Química Española de la Industria del Cuero, 2016) Bacardit i Dalmases, Anna; Díaz, Jorge; Casas, Concepció; Ollé i Otero, Lluís
En estudios anteriores se han desarrollado modificaciones químicas y físicas para obtener una tara modificada con un mayor porcentaje de taninos y con una mejor capacidad de penetración y fijación en cuero mediante una molienda y tamizado. La tara molida y tamizada con tamaños de partícula alrededor de 40-50 micrómetros da mejores resultados en términos de propiedades organolépticas y reducción de las cargas contaminantes de los baños finales. En este trabajo, este producto se utilizará como base para diferentes aplicaciones y optimizaciones, y se denominará tara modificada. El objetivo de este trabajo es estudiar diferentes combinaciones de tara modificada con otros productos, es decir, quebracho, mimosa, dispersantes y taninos sintéticos con el fin de reducir su astringencia y, por tanto, mejorar la penetración en la estructura del cuero.
Open Access
Application of highly carboxylate resins in aqueous emulsion for leather coating avoiding the use of isopropyl alcohol
(Elsevier, 2016-08) Ollé i Otero, Lluís; Baquero Armans, Grau; Solé Ferrer, Maria Mercè; Cuadros Domènech, Rosa; Bacardit i Dalmases, Anna
Today, the first stages of the finishing processes of buffed cattle hides or full loose grain–known as impregnation–are largely carried out with acrylic resins and penetrating agents (typically, a mixture of surfactants and solvents). This application aims to strengthen the partially buffed grain layer bound to the rest of the dermis. To that end, a composition of emulsified acrylic resins is used, as well as a penetrating agent – usually isopropyl alcohol –, and water. The process examined consists in the application of acrylic polymers in an aqueous emulsion that, because of their structure, size, and properties no longer require the use of the isopropyl alcohol contained in the penetrating agents. The use of this alcohol causes adverse effects on the health of workers that are exposed to emanations of isopropanol vapors (irritant to eyes, respiratory tract, and skin) in the work environment. Effects from prolonged exposition and inhalation may lead to headaches, dizziness, drowsiness, nausea and, ultimately, to unconsciousness. By using the new polymers developed in this work, the negative environmental effects of the finishing process can be minimized. At the same time, the use of these highly carboxylate resins avoid the exposure to isopropyl alcohol, which is harmful to the health. In addition, the volatile organic compounds (VOC) are reduced without compromising the appearance, performance and fashion requirements that are expected in the final product.
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.
Open Access
Olipo-wet olive pomace, a new renewable source for leather retanning
(ICAMS, 2020-10) Gaidau, Carmen; Stanca, Maria; Simion, Demetra; Niculescu, Olga; Alexe, Cosmin-Andrei; Casas, Concepció; Bacardit i Dalmases, Anna; Tonea, Stoica; Paun, Gabriela
The aim of OLIPO project is to find suitable extraction methods for an important waste of olive oil production, wet olive pomace, in view of reclaiming it as tanning and retanning material, alternative to petroleum origin materials. The total volume of wet olive pomace in Mediterranean countries where olive crops are traditional is about 80% of processed olives and is the result of a two-phase continuous extraction process. Wet olive pomace is rich in polyphenolic compounds, fats, tannins, non-tannins, possible to be extracted, concentrated, chemical processed in view of developing a new tanning product. The use of new renewable materials from oil industry as biobased tanning material for leather industry represents an important step in lowering carbon footprint of both sectors and complies with circular economy principles. The antioxidant and antimicrobial properties of olive oil pomace can be exploited in view of increasing the efficiency of the new product. The paper presents the characterisation of four kinds of wet olive pomace wastes, water and water-organic solvent extracts as tanning materials in order to select the methods for a new tanning material elaboration and testing on leathers in retanning processes.
Open Access
Synthesis of polyurethanes with low volatile organic Compounds content for upholstery and automotive Articles
(ICAMS, 2020-10) Bacardit i Dalmases, Anna; Sorolla, Sílvia; Casas, Concepció; Conde Mateos, Mireia; Ollé i Otero, Lluís
The manufacture of upholstery and automotive articles is linked to the release of Volatile Organic Compounds (hereinafter VOCs) during their manufacture, which have short and long-term effects on the health of users and the environment. In the leather sector, around 40 kg of VOCs are generated per 1000 kg of raw skin. This research work has focused on the synthesis of new and more sustainable urethane-based polymers that, in turn, allow the quality requirements of the finish to be met, which vary depending on the leather article manufactured. The main objective of the study is to minimize the content of VOCs in the different aliphatic polyurethanes synthesized in a pilot-scale reactor, making small modifications to the synthesis formulations. The synthesis route developed is based on the preparation of polymers of ionomeric polyurethanes and their subsequent dispersion in water. In the synthesis processes developed, the content of coalescing solvents and neutralizing agents, which directly contribute to the concentration of VOCs of the urethane polymers, is eliminated and / or minimized as much as possible. The new urethane-based polymers obtained have been analyzed according to the parameters of pH, viscosity, density and percentage of solids in the resin. Likewise, organoleptic tests (color, transparency, hardness, touch and tacking) and physical tests (tensile strength, water absorption, hardness and color change at 100°C for 24 hours) have been carried out on the film corresponding to each synthesized polyurethane resin. These products will be introduced in finishing formulations designed to obtain high-performance upholstery and automotive leather with minimal impact in terms of VOC content at the pilot level. Tests of fastness and physical resistance have been carried out to evaluate the performance of these leathers.
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.
Embargo
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
Exploring the feasibility of substituting mimosa tannin for pine bark powder. A LCA perspective
(Elsevier, 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.
Open Access
From Leather Wastes back to Leather Manufacturing: The Development of New Bio-Based Finishing Systems
(MDPI, 2023-04-16) Gargano, Marika; Bacardit i Dalmases, Anna; Sannia, Giovanni; Lettera, Vincenzo
The leather industry is currently between two opposing paths: on the one hand, recent legislative trends in terms of the eco-sustainability of industrial processes are leading leather manufacturing towards the development of cleaner production methods; on the other hand, the spread of new alternative materials to leather is driving the leather industry to improve its competitiveness by developing new innovative and high-quality products. Leather finishing is one of the most important phases of leather production, and is capable of improving its quality and organoleptic properties. However, this phase is characterized by the use of polluting chemical products, such as volatile organic compounds, potentially toxic crosslinking agents, and hardly biodegradable resins. In this context, this research work aims to develop a finishing formulation capable of giving leather the durability and quality properties required by the market, while at the same time, being eco-sustainable. Specifically, the aim of the present work is to suggest a new finishing formulation in terms not only of green technology but also of a circular production flow, by recovering solid leather wastes. The developed finishing system is based on the application of collagen, extracted from tanned wastes through an enzymatic treatment, to be cross-linked and bound to the leather surface. This new bio-based leather finish is compared to a resin-based leather finish, and shows the same quality standards as those requested by the market.

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