Sorolla, S.; Flores, A.; Canals, T.; Cantero, M.R.; Font Vallès, Joaquim; Olle, L.; Bacardit, A. Journal of the American Leather Chemists Association Vol. 113, num. 3, p. 88-93 Data de publicació: 2018-03-05 Article en revista
The main aim of this study is to carry out a qualitative and semiquantitative analysis of tannin extracts as an alternative to the official analysis method ISO 14088 – IUC 32, so that a correlation between the two methods is established.
From the point of view of the chemical composition, tannins are classified into two major groups: i) condensed tannins, also called flavanols or catechins, and ii) hydrolysable tannins, also called pyrogallic tannins.
Today, the most widely used conventional extracts are quebracho, mimosa, chestnut, and tara. Quebracho and mimosa are condensed tannins, whereas chestnut and tara are hydrolysable tannins.
The following extracts were used in this study: tara powder, commercial mimosa and quebracho extracts and extracts derived from grape seed, containing both condensed and hydrolysable extracts.
The development of this new method will allow a faster and less expensive estimate of the amount of tannins present in a tannin extract.
Manich, A.M.; Cuadros Domènech, S.; Font Vallès, Joaquim; Bacardit, A.; Combalia, F.; Marsal , A. Journal of the American Leather Chemists Association Vol. 112, num. 5, p. 168-179 Data de publicació: 2017-05-08 Article en revista
Given the carcinogenic character of formaldehyde, it should be reliably determined in any substrate . The EN ISO 17226 Standard is the Official Method to quantify formaldehyde in leather. However, sorne misunderstandings may arise from the practica! conditions given by the Standard for the extraction of formaldehyde. Two agitation methods (magnetic agitation and reciproca! linear agitation), which fulfill the conditions of the Standard, have been used for the extraction of formaldehyde in twenty two samples of wet-blue split leather treated with resins synthesized with formaldehyde and with/without the addition of vegetable compounds. The agitation method influences the formaldehyde content and differences between the agitation methods depend on the formaldehyde resins and vegetable compounds applied. Magnetic agitation leads to formaldehyde contents that are 26% greater than those obtained when the reciproca! linear agitation method is used. Major brands specify allowable limits for formaldehyde content, which depend on the user (adult or babies) and whether the article is i n direct contact with t he skin. A high percentage of disagreement (33.3%) has been observed between the agitation methods in fulfilling the allowable limits. One-third of the formaldehyde content results that fulfilled the allowable limits with the reciproca! linear agitation method failed when the magnetic method was applied . The situation u rges the clarification of the shaking method in the EN ISO 17226 Standard to avoid the high leve! of contradictory results between methods that meet the agitation conditions of the Standard.
The purpose of this work is to compare the environmental impact of two systems for processing bovine leather: (i) a new continuous system that consists in dehydration and tanning and post-tanning by immersion versus (ii) the traditional system using drums. In order to better assess the environmental impact of this new tanning system, the life cycle assessment methodology has been chosen to perform calculations on various impact categories, including the global warming potential (CO2 equivalent emissions), and the energy consumption for both the traditional and the new tanning processes. When assessing the environmental impact of the new system, it is clear that a reduction in the use of acetone during the process will positively affect the environmental outcomes. In this regard, results show reductions on the impacts in eight out of the eleven impact categories analyzed as well as reductions on energy consumption. However, the acetone loss considered (5%) led to higher impacts compared to the traditional system in three specific impact categories, which can be improved by reducing the acetone emission to 2.5%.
The aim of this work was to develop new systems of micro/nanocomposites to confer new functions to materials used for seats of public vehicles and public spaces. Specifically, this study focuses on antibacterial effect for leather and technical textile substrates.
The first stage of the research consists of a selection of micro/micro/nanomaterials and active principles: selection and evaluation of micro/nanoparticles, antibacterial and antifungal substances. In the second stage, the process of encapsulation of active principles was studied. The research includes optimization of the encapsulation process by improving the size and stability of the capsules. In addition, the synthesis of a hybrid organicinorganic polymer acting as a micro/micro/nanomaterial carrier was developed.
To understand the mechanisms of synthesis and action of micro/micro/nanomaterials, characterization techniques have been used: scanning electron microscopy SEM and optical microscopy, analysis and distribution of particle size (DLS, Zetasizer). Regarding the antibacterial and antifungal ability of micro/nanocomposites, we adapted standard ASTM 2180-07 “Test methods for determining the activity or incorporated antimicrobial agent (s) in polymeric or hydrophobic materials.”
Different products have been developed and the results obtained allow us to conclude that the synthesized products showed inhibition to the growth of bacteria and fungi on the contact surface.
In three previous studies, it has been used the fruit of the tara tree (Cæsalpinia Spinosa) as a pre-tanning agent 1. This new tailored tara product will be able to facilitate the penetration of the tannin molecules through the leather section, avoiding or reducing the use of aldehydes, syntans, common vegetable tannins and other mineral salts. The aim of this part of the study is to manufacture final articles meeting the parameters set by different regulations, and assess if this modified tara can be marketed and used in the industry to replace some less sustainable products.
Bacardit, A.; González, M.; van der Burgh, S.; Armengol, J.; Olle, L. Journal of the American Leather Chemists Association Vol. 111, num. 3, p. 113-122 Data de publicació: 2016-02-16 Article en revista
In this work we develop a new tanning process (that we call wet-bright) that produces leather free of chromium, aldehydes, aldehyde precursors and organic solvents. Due to the mineral character of the new system, the leather offers a perfect dyeability and high dye affinity, allowing for very bright colors in all leather applications. The leathers offer a perfect dyeability due to the brilliant whiteness of the wet-bright intermediate. This new system consists of the application of Tanfor TTM system (from Kemira) which is safe for both humans and environment and is not classified as hazardous. In addition, when compared to existing traditional processes, there are economic and environmental advantages resulting from the use of this new system.
The aim of this work was to design a new pretanning formulation by using the fruit of the Tara tree (Caesalpinia Spinosa) as the sole source of vegetable tannin. The innovative aspect of this work embodies a new-tailored tara product which gave its tannin the enhanced ability to readily penetrate the leather cross section, and thus made it unnecessary for the tanner to add aldehydes, syntans, other common vegetable tannins and mineral salts.; Specifically, physical modifications had been developed in part II of this broad study to obtain a modified tara with a higher percentage of tannins and with a better ability to penetrate/fix in leather by sieving and milling (see Low carbon products to design innovative leather processes. Part 1: determination of the optimal chemical modification of tara(1) and Low carbon products to design innovative leather processes. Part II: determination of the optimal physical modification of tara)(2) We developed in this work an innovative, eco-friendly and optimal wet white formulation which has a maximum offer to leather of 9% modified tarn and a maximum 2% naphthalene sulphonic syntan dispersing agent.
This paper analyzes, from a life cycle perspective, the environmental performance of a newly developed chromium-free tanning process compared to the conventional one, in China. Both processes were evaluated by using carbon footprint, energy consumption and toxicity indicators. Chromium-free tanning process has been found to significantly reduce the considered impact categories compared to conventional tanning. The impact contribution of each process step was calculated, with the tanning step being the major contributor. Results show that the production of chemicals used in the tanning process, have a significant effect on the impacts evaluated. Some of these chemicals have been substituted with similar ones (used as proxies) when no manufacturing-data was available in the databases. Thus, it is important for future and more precise LCA studies to develop databases on the specific chemicals used. This study is a first estimation of the impacts and will help on the decision of expending time and efforts on developing and optimizing the new technology. The results show that it is interesting to use this LCA methodology to environmentally evaluate new research processes and products, before industrial scaling and implementing them, to optimize research time and efforts towards the most environmentally promising products and processes
This paper analyzes, from a life cycle perspective, the environmental performance of biodiesel obtained from leather industry fleshing waste (BDF). The indicators used for this environmental evaluation are: global warming potential (GWP) and energy return on investment (EROI). The contribution of each process-step in both GWP and EROI was determined. Transesterification of fat to obtain the BDF has been proved to be the most significant step in the process, mainly due to the consumption of methanol A comparison between BDF and petroleum diesel obtained from non-renewable oil has also been performed using the same indicators. The results show a clear preference for BDF, although data from industrial real plants has to be considered in further works for BDF process to provide more accurate results.
The aim of the present work was to develop a new tanning process (wet-bright) that produces perfectly white leather meeting all of the requirements for many kinds of articles, such as automotive, garment and shoe upper. This new process gives leather that is free of chromium, aldehydes, aldehyde precursors and organic solvents. It is the application of a new system based on a product designated Tanfor TTM from the manufacturer Kemira Chem Solutions. When compared to existing traditional wet leather processes, there are economic and environmental advantages resulting from the use of this new system. Also, the mineral character of the new product system offers leathers with high dye affinity; thus enabling very bright colors in all leather applications. We believe this leather offers such perfect dyeing properties because of the brilliant whiteness of the wet-bright intermediate substrate
Conventional methods for chromium removal from industrial effluents may be limited by technological or economical constraints, especially when they are applied to dilute metal solutions. Thus, biotechnological processes, which are efficient at low metal concentrations and require the use of fewer chemicals, may play an important role. The chromium recovery proposed here is based on the specific uptake of this metal by acidophilic fungi. Fifty acidophilic fungal isolates from the Río Tinto basin, an extreme acidic environment, were tested. Most of them were resistant to Cr(III) and Cr(VI) solutions at concentrations up to 10 mmol/L. The influence of different experimental conditions was evaluated (medium concentration, kinetics, requirement of induction etc.). Fungal isolate 143 was able to remove 63% of Cr(III) at 0.1 mmol/L, 74% at 1 mmol/L and 21% at 10 mmol/L. These are the best Cr(III)-fungal-uptake results at acidic pH described in the literature so far. It should be possible to use these acidophilic fungi, for example in tannery wastewater, as they can resist chromium concentrations and pH values found in these effluents (between 6.5-7.5 mmol/L Cr III and pH as low as 3-4)
This study considers the fruit of the tara bush as a sustainable source for tanning agents and proposes alternatives to
chromium and other mineral salts and vegetable extracts. Specifically, physical modifications have been developed in
part II of the study to obtain a modified tara with a higher percentage of tannins and with a better level of penetration
(see Low carbon products to design innovative leather processes. Part I: determination of the optimal chemical
modification of tara).1 The physical modification of tara focused on milling and sieving. The different products
obtained have been characterized and applied to leather samples in order to evaluate the degree of penetration and stabilization in the leather structure
Current European legislation demands a reduction in the amount of voltaile organic compounds (VOCs) used in industrial processes. The presence of these compounds in the leather industry arises from the chemicals used in the various stages of the leather manufacturing process. An important aim of tanners is to reduce or eliminate. VOCs, without lowering the quality of their leather products. The HS-SPME-GC-MS method is an innovation in leather analysis. The solid phase micro extration (SPME) is a sample preparation technique used for the extraction of volatile and semi-volatile organic compounds and is becoming widely accepted as the technique of choice for many applications and that can be connected to gas chrompatography. The main advantages of this technique are speed, sensibility, and the fact that it requires no sample handling or solvent extraction. Other advantages include the fact that the concentration and the extraction are reached simultaneously and that it enables on-site extraction of the analyte, even without the prior destruction of the sample. This paper shows the development of a new HS-SPME-GC-Ms method with a deuterated internal standard for the detection and identification of volatile organic compounds emitted by leather. This method enables us to carry out a simple and rapid determination of the qualitative and semi-quantitative composition of the organic compounds in the samples
Este estudio considera el fruto del arbusto tara como fuente sostenible de agentes curtientes y propone alternativas a las sales minerales y extractos vegetales para uso comercial. Específicamente, en la parte I del estudio diversos procesos de modificación física y química se han desarrollado con el fin de obtener una tara modificada con un mayor porcentaje de taninos que permita mejorar su capacidad de curtido. Varios procesos de extracción acuosa a diferentes temperaturas se han desarrollado y optimizado con el fin de disminuir la astringencia y facilitar la penetración de las moléculas de tanino a través de la estructura de cuero.
Castell, J.; Sorolla, S.; Jorba, M.; Aribau, J.; Bacardit, A.; Olle, L. Journal of the American Leather Chemists Association Vol. 108, num. 6, p. 221-230 Data de publicació: 2013-06-03 Article en revista
This study considers the fruit of the tara tree as a sustainable source for tanning agents and proposes alternatives to the commercial mineral salts and vegetable extracts to comply with environment and social concerns. Tara tannins have been used in retanning formulas in leather processing and its properties are well known. This work aims to optimize formulations using tara as a pre-tanning agent. Combinations with a naphthalene sulphonic syntan are used to obtain an innovative wet-white recipe in which shrinkage temperature, tensile strength, tensile elongation, tear load and lightfastness properties are considered as statistical variables
Font Vallès, Joaquim; Reyes, M.; Cuadros, S.; Bacardit, A.; Olle, L.; Marsal , A. Journal of the American Leather Chemists Association Vol. 108, num. 2, p. 41-47 Data de publicació: 2013-02-04 Article en revista
Solid-phase microextraction (SPME) was optimized for extraction of the leather preservative agents 2-(thiocyanomethylthio)-benzothiazole (TCMTB), 4-chloro-3-methylphenol (PCMC), 2-phenylphenol (OPP), 2-Octyl-3(2H)-isothiazolone (OIT), 2-mercaptobenzothiazol (MBT) and 3-iodo-2-propynyl-butylcarbamate (IPBC) in spent tanning floats. Determination was carried out by high performance liquid chromatography (HPLC) with photo diode array detection (PDA). The following parameters were studied to achieve the maximum efficiency in extraction: fiber type, adsorption conditions (extraction time, ionic strength, temperature) and desorption parameters (time, temperature and composition of the desorption solvent). Results indicate that SPME using a 60um polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber is appropriate for the extraction of these types of compounds. Recoveries ranged from 82% to 116% with RSDs between +-8% and +-12% and limits of detection below 1 mg/L except for IPBC. The optimized procedure was successfully applied for the determination of leather preservatives in eleven residual tanning floats taken from different companies. This method enables us to determine quantitatively the fungicides contained in th residual floats. Consequently, it will constitute a very useful tool to improve the preservative uptake in leather manufacturing processes
Since leather is strongly affected by three main environmental parameters: temperature, relative humidity and UV radiation, this piece of research focuses on the effect that these three factors have on chrome-tanned leather ageing. Chrome tanned leathers were exposed to weathering effects in a climatic chamber in order to identify the most important variables affecting this weathering process and also to check for any possible interactions. Both a multilevel centralized factorial experimental design and an analysis of variance (ANOVA) were used as statistical tools for estimating the effects of the parameters
This work describes the synthesis of new leather finishing acrylic resins. Four resins ware synthesized varying the concentration of ethyl acrylate, and metracrylic acid. Sodium lauryl sulphate was used as emulsifying system. By means of an experimental design, an optimal resin for leather impregnation was defined. The results obtained indicated that the variation of the monomer concentration influences the resin properties, the hardness of the film, and the penetration into the leather. Most importantly, this new highly carboxylate acrylic resin enables leather impregnation without the use of surfactants or penetrating agents
Font Vallès, Joaquim; Reyes, M.; Cuadros, S.; Bacardit, A.; Marsal , A. Journal of the American Leather Chemists Association Vol. 106, num. 11, p. 341-348 DOI: 10.1117/1.3050421 Data de publicació: 2011-11-02 Article en revista
Castell, J.C.; Fabregat, C.; Sorolla, S.; Solano, D.; Olle, L.; Bacardit, A. Journal of the American Leather Chemists Association Vol. 106, num. 10, p. 278-286 Data de publicació: 2011-10-05 Article en revista
This study considers the fruit of the tara tree (Caesalpinia spinosa) as a sustainable source for tanning agents and proposes alternatives to the commercial mineral salts and vegetable extracts to comply with an increasing demand that concers low carbon footprint raw materials and health safety. Although tara tannins have been used in the leather industry and its properties being well known, the experimental part of the work aims to optimize innovative formulations using tara as wet-white pre-tanning agent. Combinations with naphthalene sulphonic and phenol condensation syntans will be used for wet white. Experiments have been designed by Simplex with centroids statistical calculations to obtain an optimized formulation. Tests are evaluated determining shrinkage temperature, tensile strenght, elongation, tear resistance and light fastness.
In the last two years, Europe has experienced a rise in skin allery and dermatitis due to goods and Asian provenance that have been treacted with dimethylfumarate (DMFU). Accordingly,laboratories in the leather and foodwear sectors have been obliged to develop analytical methods to determine the presence of this substance given de absence of an official method. The ban on DMFU as laid down in Decision 2009/251 of the European Union establishes a maximun concentration of DMFU in products of 0.1 mg/Kg. A simple nom-destructive rapid method based on manual headspace solid-phase micro extraction (HS-SPME) and gas cromatography-mass spectrometry (GC-MS)is proposed to detect DMFU in leather and footwear. Thereafter, the samples which DMFU is detected are analysed by solid-liquid extraction (SLE) with acetone after which DMFU is quantitatively determined by GC-MS. The quantitative method in validated in terms of linearity, precision, sensivity and recovery; demostrating its reliability. Quantification of this performed used naphthalene-D8 as internal standard. The detection limits are 0.005 mg/Kg and 0.03 mg/Kg for the HS-SPME-GC-MS and SLE-GC-MS methods, respectively. Given that these limits are bellow the maximun limit of 0.1 mg/Kg imposed by the European Union, the proposed methods are suitable for determining DMFU content in real samples.
Since upholstery leather is considered a very high-tech product, a long service life is expected by the costumer.
However, this type of leather can undergo extreme environmental conditions that may cause premature ageing. This work deals with the study of the effect of temperature,
relative humidity, and UV radiation on leather ageing. Leathers with wet-white tannage were exposed to weathering effects
using a climatic chamber in order to identify the most important variables affecting this weathering process and to
check for interactions. Both a multilevel centralized factorial experimental design and an analysis of variance (ANOVA)
have been employed as statistical tools for estimating the effects of the parameters.
Lalueza, J.; Rius, A.; Puig, R.; Marti, M.; Martí, J.F.; Rodriguez, N.; Amils, R. Journal of the American Leather Chemists Association Vol. 105, num. 7, p. 214-221 Data de publicació: 2010-07 Article en revista
Heavy metals in waste waters and sludge may cause significant environmental problems, and it is known that conventional recovery technologies cannot always achieve satisfactory treatment. For example, they are inappropiate to completely recover the chromium in the case of waste waters from the tanning process. Chromium can be recovered (by precipitation)from effluents that contain high concentrations of this metal. However, effluents from the later stages in present day tanning process often have a low concentration of chromium that cannot be recovered and is found in the sludge of the wastewater treatment plant (WWTP). The aim of our research is to recover and reuse the chromiun (III) from post-tanning effluents by means of a biotechnological sequestering method using acidophilic fungi. In this study, we tested acidophilic fungi capable to grow in the presence of chromiun in waste waters from various stages of a real post-tanning process. When the post-tanning process was carried out on a pilot plant scale in which conventional rechroming and neutralisation stages were undertaken and the use of additional chemicals was avoided, chromium (III) sequestration values of above 95% were obtained. As these results are so promising, further studies will focus on searching for more resistant fungal strains and determining which of the chemicals used in the post-tanning process can be avoided or replaced by alternatives.
Morera, J.M.; Bartolí, E.; Serrano, M.; Combalia, F.; Borràs, E.; Olle, L.; Bacardit, A. Journal of the American Leather Chemists Association Vol. 105, num. 5, p. 150-159 Data de publicació: 2010-05 Article en revista
This work studies the effect of several variables on a series of properties of the final leather obtained from chrome tanning, using ultrasounds as the sole mechanical effect during the tanning operation. The variables studied (at two levels by means of a 23 factorial design) are tanning temperature, condition of chrome offered (solid or dissolved) and salt basicity. Our studies indicate that the results obtained measuring parameters such as struck-through time of tanning agent, chromium uptake and its distribution, shrinkage temperature, tensile strength, tear load, grain distension and leather burst distention significantly depend on the previously selected level of one or more of the variables being studied. The study of the evolution of the concentration and basicity of the chromium salts has led us to conclude that reutilization is possible. Results show that ultrasound use in chrome tanning is a possibility to consider in the case of leather goods in which the use of drum may not be advisable.
Bacardit, A.; Borras, M.D.; Soler, J.; Herrero, V.; Jorge, J.; Olle, L. Journal of the American Leather Chemists Association Vol. 105, num. 2, p. 51-61 Data de publicació: 2010-02-11 Article en revista
Leather is a natural material with many applications: automotive, domestic upholstery, buildings, aviation, maritime, personal safety, etc. For each of these sectors, fire behavior is a field of particular interest. Unfortunately, there are many testing methods and different flammability standards depending on material application and end use. Therefore, there are different ways of approaching the whole flammability issue. In this work, different approaches for analyzing the fire resistance of leather are examined: (i) influence of the type of tannage, (ii) influence of the type of leather, (iii) influence of the type of retannage, (iv) influence of the type of fatliquor, and (v) influence of the use of flame retardants. The results indicate that leather presents natural fire resistance. However, the type of leather, type of tannage, retannage and fatliquor effect the flammability behavior of leather. In addition, the use of flame retardants slightly improves the smouldering properties of leather.
Morera, J.M.; Bartolí, E.; Combalia, F.; Borràs, E.; Castell, J.; Sorolla, S. Journal of the American Leather Chemists Association Vol. 105, num. 11, p. 369-375 Data de publicació: 2010 Article en revista
This study concerns the implementation and improvement of a system that applies ultrasound technology to vegetable tanning floats. The system is versatile and requires no major modifications or investment expense for tanneries. In particular, the study investigated grain fineness and fixation of tannins in relation to several mechanical approaches, which included: no mechanical effect (pits), drum, ultrasound, and ultrasound plus drum. A comparative study of energy expenses on the basis of the mechanical effect being used was also carried out.
Bacardit, A.; Olle, L.; Morera, J.M.; Bartolí, E.; Cuadros, R.; Cobos, M. Journal of the American Leather Chemists Association Vol. 104, num. 3, p. 103-112 Data de publicació: 2009-03 Article en revista
Roig, J.; Font Vallès, Joaquim; Marginet, X.; Jorba, M.; Olle, L.; Bacardit, A.; Puig, R. Journal of the American Leather Chemists Association Vol. 104, num. 4, p. 139-148 Data de publicació: 2009 Article en revista
This paper documents a technical feasibility study opf tannery wasterwater which was reclaimed (treated) and reutilized in tannery leather making processes. The studied waste water was processed in the waste water treatment plant owned by Igualada tanners (IDR), in Spain. The objectives included reduction of city fresh water consumption by the tanners of this city. A pilot plant using membrane technology, determined to be the most appropiate technology in this case, was installed at the IDR wastewater treatment facility. It worked in three consecutive stages: pre-treatment by sand filtration, subsequent ultrafiltration, and then reserse osmosis. The reclaimed water was of the highest quality, superior to any other water currently available to city tanners. The right sides of 24 calf hides were fully processed with the reclaimed water, while the left sides of the same hides were processed with softened tap water. Three different leather articles were produced. No significant differences were detectable between the left and right sides, neither organoleptically nor analytically.
Morera, J.M.; Bartolí, E.; Bacardit, A.; Olle, L.; Díaz, V.; Shendryck, A. Journal of the American Leather Chemists Association Vol. 103, num. 4, p. 151-157 Data de publicació: 2008-04 Article en revista
Morera, J.M.; Bartolí, E.; Olle, L.; Bacardit, A.; Fabregat, G.; Díaz, V.; del Río, J. Journal of the American Leather Chemists Association Vol. 103, num. 4, p. 158-161 Data de publicació: 2008-04 Article en revista
Font Vallès, Joaquim; Viera, S.; Cuadros, S.; Rius, A.; Reyes, M.; Verdú, E.; Jorba, M.; Juárez, M.; Marsal , A. Journal of the American Leather Chemists Association Vol. 103, num. 3, p. 53-61 Data de publicació: 2008 Article en revista
The colorimetric determination of formaldehyde in a water extract of a leather sample is a procedure that has been criticized because of possible interferences of other aldehydes and coloured substances that could interfere in the spectrophotometric detection. The measurement by liquid chromatography HPLC is an alternative method that was developed some years ago. This method is more sophisticated but more selective and free of the aforementioned interferences. It is not sensitive to coloured extracts. With the implementation of HPLC equipment in many laboratories, this choice has become feasible in our sector. The process is selective. Formaldehyde is separated and quantified as a derivative from other aldehydes and ketones by liquid chromatography. The free-formaldehyde and formaldehyde which is hydrolysed during extraction to yield free-formaldehyde are detected by this method. The sample is eluted with water at 40ºC. The eluate is mixed with 2,4 dinitrophenylhydrazine, whereby aldehydes and ketones react to yield the respective hydrazones. These are separated by means of a reversed-phase HPLC method, detected at 350 nm and quantified. The aim of this work is to present a collaborative inter-laboratory study coordinated by the Igualada Leather Technology School and carried out with four other laboratories that had previosly implemented the HPLC method or that were planning to do this. Determination of formaldehyde content in leather was carried out in each laboratory in accordance with prEN ISO 17226:2005 - HPLC Standard, developed by the Committee CEN/TC 289. Part 2 of the ISO 5725 Standard (Basic method for the determination of repeatability and reproducibiliry of a standard measurement method) was applied to examine the results. The study proved successful. The HPLC method achieved very reproducible results between laboratories. This work has also demonstrated that other aldehydes, glutaraldehyde included, do not interfere in the chromatographic method. The use of a PDA detector increases the confidence of the detection of formaldehyde in leather samples
The aim of this study was to develop at pilot plant level two systems of pickle-tanning that would reduce both the amount of waste water and its content in chrome and chlorides while obtaining leathers that are commercially acceptable. In the first one, the effect of the variation of the final tanning temperature as well as the system of adding the basificant in the formulation of a chrome tanning without float were studied. A 87 percent reduction of the residual float was obtained with this system. The amount of chrome in wastewater was reduced by 96 percent in this study as compared to taht of a tradtional tanning process. The reduction of chlorides in all the tanning tests without float was maintained at around 94 percent. In the second one, the pickle process was carried out without float and with low salt addition, and the inorganic acids were replaced by a sulphoaromatic acid. The effect of the variation of the final temperature was studied in the tanning, as well as the type of basification used for the chrome exhaustion in the residual float. A 88 percent reduction of the residual float was obtained with this system, as well as a 99 percent reduction in chrome content in wastewater and a 93 percent reduction in chlorides content in wastewater.
Rius, A.; Font Vallès, Joaquim; Cuadros, R.; Santiago, M.; Verdú, E.; Marsal , A. Journal of the American Leather Chemists Association Vol. 97, num. 7, p. 277-282 Data de publicació: 2002-03 Article en revista