Leather Process Research Articles

Characterization and Properties of Organic Silicon Modified Vegetable Oil Fatliquor

The vegetable oil fatliquor (VF) was prepared by rapeseed oil, 1, 2-ethylenediamine and acrylic acid. The synthesis of a silicon modified vegetable oil fatliquor (SVF) was carried out using VF and polyether silicon by stirring and ultrasonic treatment. VF and SVF were measured by Fourier Transform Infrared Spectroscopy (FT-IR), thermogravimetry(TGA) and Transmission electron microscopy (TEM) respectively. SVF was applied in leather fatliquoring process, compared with product XQ-F3. The results indicated that polycondensation between hydroxy of polyether silicon and carboxylic hydroxy of VF occurred, the performance of VF could be improved by polyether silicon. The emulsifying surface tension of SVF decreased to 17.0 N/m, compared with 18.2 N/m of VF.The application results showed that the physical mechanical properties of leather fatliquored by SVF was equivalent to the leather fatliquored by industrial XQ-F3 fatliquor.

Synthesis of Vinyl Polymer/ ZnO Nano Composite and its Application in Leather Tanning Agent

Vinyl polymer (dimethyl diallyl ammonium chloride /acrylic acid/2-hydroxyethyl acrylate/acrylamide) was synthesized via free radical polymerization, and then vinyl polymer/zinc oxide nano composite (PDM/ ZnO) was prepared by ultrasonic treatment and used for leather tanning agent. PDM and PDM/ZnO was characterized by FT-IR and XRD. The morphology of nano composite was observed by TEM. Moreover, PDM and PDM/ZnO combined with 2% chromate tanning agent were applied in leather tanning process and then the thermal and mechanical properties of the resultant leather were measured. FTIR results revealed that the polymerization reaction of PDM was complete and the carboxyl groups of PDM could react with the hydroxyl groups on the surface ZnO. The crystalline structure of the ZnO nanoparticles in the nano composite was not altered according to the XRD patterns. TEM results showed that nano ZnO was encapsulated on the surface of PDM copolymer chain and nano composites particles dispersed evenly. The results indicated that the tensile strength increased by 11.90% and the tearing strength improved by 23.72%. Compared with PDM, TGA plots showed that the thermal stability of the resultant leather tanned by PDM/ZnO nano composites was improved to a certain extent.

Analytical techniques used for the evaluation of a 19th century quranic manuscript conditions

The manuscript studied here dates to 19th century, and consists of paper pages and leather bookbinding. This study aims to use analytical techniques in order to identify the components of the manuscript and to explain its deterioration process. Visual assessment, isolation and identification of fungi, pH measurements, and investigation of the surface morphology by a scanning electron microscope (SEM) were used to explain paper and leather deterioration. X-ray diffraction with EDAX, Fourier Transform Infrared Spectroscopy (FTIR), and chemical analysis were used to identify pigments, binder of pigments, ash, lignin, and the α-cellulose content of papers. The shrinkage temperature measurement was used to explain the deterioration process of leather. SEM was used to identify the type of animal skin used for the bookbinding and high performance liquid chromatography (HPLC) was used to identify the vegetable tanning material used with the bookbinding. The results revealed that the ink used was a mixture of carbon with iron gall. The pigments used on the paper were gold leaf or gold shell, cobalt oxide, and mercuric sulfide for the gold, blue and red colors respectively. Sodium chloride was the main salt crystallized on the surface of paper. Calcium carbonate was the filler used in the paper making process. Cotton fibers may have been used as a raw material in the creation of paper. The values of the shrinkage temperature and pH were lower than in normal conditions, indicating that the leather bookbinding suffers from deterioration. Aspergillus sp., and Penicillium sp. were the most dominant fungi found on the manuscript. Goat skin was identified as the animal skin of the bookbinding, and Acacia Arabica was identified the tanning material used with the bookbinding. The condition of the manuscript studied with its components play an important role in its deterioration.

Synthesis and properties of modified rapeseed oil/montmorillonite nanocomposite fatliquoring agent

Modified rapeseed oil/montmorillonite (MRO/MMT) nanocomposite was prepared by using rapeseed oil, ethylene diamine, acrylic acid, and MMT. In order to compare MRO/MMT with MRO and a market product XQ-F3, they were applied in leather fatliquoring process, respectively. Sensory evaluation, physical and mechanical properties, and flame-retardant property of leather treated with different fatliquoring agents were measured. X-ray diffraction (XRD) results showed that MRO could smoothly enter the interlayer of MMT. The emulsifying property of MRO/MMT was confirmed better than that of MRO. The application results also showed that MRO/MMT has good fatliquoring effect. Meanwhile, it can increase leather strength and improve leather flame-retardant performance.

Preparation and Application of Poly (Methacrylic Acid)/Montmorillonite Nanocomposites

Because the leather tanned by a chrome tanning agent could be endowed with excellent performances, such as high hydrothermal stability, good physical-mechanical properties, and outstanding handle feeling, chromate is used extensively in leather making. But in recent years, the chromate was considered as a poisonous chemical to the environment. Hence, there is no moment to be lost to develop new tanning agents. The research is also enclosing this point to be done. In this article, the poly (methacrylic acid)/montmorillonite (PMAA/MMT) nanocomposite was prepared via monomer in situ polymerization. The resulting nanocomposite was characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and solid-state nuclear magnetic resonance (solid-state NMR). Finally, the PMAA/MMT nanocomposite was applied to the leather tanning process. The results of XRD, FT-IR, and solid-state 13C-NMR show that methacrylic acid (MAA) has been polymerized in montmorillonite (MMT) interlamellar, and the PMAA/MMT nanocomposite formed belongs to intercalated-exfoliated nanocomposite. The application results show the hydrothermal stability and physical-mechanical properties of the leather tanned with nanocomposite are superior to those of the leather tanned with PMAA.

Tannin Fingerprinting in Vegetable Tanned Leather by Solid State NMR Spectroscopy and Comparison with Leathers Tanned by Other Processes

Solid state 13C-NMR spectra of pure tannin powders from four different sources – mimosa, quebracho, chestnut and tara – are readily distinguishable from each other, both in pure commercial powder form, and in leather which they have been used to tan. Groups of signals indicative of the source, and type (condensed vs. hydrolyzable) of tannin used in the manufacture are well resolved in the spectra of the finished leathers. These fingerprints are compared with those arising from leathers tanned with other common tanning agents. Paramagnetic chromium (III) tanning causes widespread but selective disappearance of signals from the spectrum of leather collagen, including resonances from acidic aspartyl and glutamyl residues, likely bound to Cr (III) structures. Aluminium (III) and glutaraldehyde tanning both cause considerable leather collagen signal sharpening suggesting some increase in molecular structural ordering. The 27Al-NMR signal from the former material is consistent with an octahedral coordination by oxygen ligands. Solid state NMR thus provides easily recognisable reagent specific spectral fingerprints of the products of vegetable and some other common tanning processes. Because spectra are related to molecular properties, NMR is potentially a powerful tool in leather process enhancement and quality or provenance assurance.

Chemical Engineering Applications on Unit Operations of Tanning Industry–Case Studies

—Tanning industries still follow primitive methods to handle chemicals and raw materials that give rise to spill over of costly chemicals, health hazards and hence incur losses. Computerized dosing systems are needed to reduce spillage and wastage of costly chemicals in tanning operations. The unit operations in leather making are made into modules. Engineering inputs through automation (using PLC) must be brought into picture to improve the working atmosphere and to reduce losses. The results show improved quality control and healthy work atmosphere in the industry can be achieved by use of computer aided dosing systems (CADS). Index Terms—PLC, Automation, Leather process, Tanning

Impact of tannery effluent with special reference to seasonal variation on physico-chemical characteristics of river water at Kanpur (U.P), India

An investigation has been made to ascertain the effect of tannery effluent associated with seasonal variation on river water samples collected from confluence point, upstream and downstream located near Jajmau area at Kanpur. All the samples analyzed for physico-chemical parameters including estimation of chromium. The pH at confluence point (Q) was significant (P<0.05) alkaline (7.9±0.13) during summer as compared to upstream point P3 due to dumping of untreated tanneries effluent, which suggested that utilization of salts for leather tanning process. Study shows that a significant (P<0.05) decrease in DO values (3.79±0.101 mg/L) at summer, although the higher level of DO (6.76±0.13) during monsoon season might be attributed to the dilution of the effluent by rain water. The level of BOD (41.07±1.268 mg/L) shows a significant (P<0.05) increase at confluence point during as compared to upstream point (P3) during summer. Although the level of COD at different sampling points affected with seasonal variation but it was not significant. However this study also revealed a significant negative correlation showing that as BOD and COD increases in values DO decreases with correlation of r = -0.944 (t= 6.978, P<0.05 for BOD) and r = -0.970 (t= 9.696, P<0.05 for COD). These correlation between BOD, COD and DO suggest a similar cause. The correlation analysis of TDS versus BOD and COD gives a positive correlation (r =0.9408 & r =0.8667 respectively) showing that as TDS increase BOD and COD also increases. Theses correlation analysis shows that levels of TDS, BOD and COD are highly correlated with each other in sampling area during different seasonal variation. Chromium levels were high (52.12±15.52 mg/L) in almost all sampling points with seasonal variation, thus tanneries effluent with seasonal variation showed highly adverse effect on river Ganga.

Preparation of Hyper-Branched Polymer and its Application in Synthetic Leather

The hyper-branched polymer with terminal carboxyl (HPAE-C) was prepared by modifying hyper-branched polymer with terminal hydroxyl with maleic anhydride. The molecular structure of HPAE-C was characterized by IR, 1H-NMR and 13C-NMR. The HPAE-C was used in the finishing process of microfiber synthetic leather, and its effect on the health properties of microfiber synthetic leather was studied. The results showed that hyper-branched polymer could improve the moisture absorption and permeability to water vapor of microfiber synthetic leather. When the dosage of HPAE-C was 8%, the permeability to water vapor and moisture absorption of microfiber synthetic leather were improved by 7% and 13%, respectively. The observation results obtained by using scanning electron microscope showed that HPAE-C could loose the fibers of synthetic leather.

Electrochemical oxidation and reuse of tannery saline wastewater

In this present work, electrochemical treatment of saline wastewater with organic (protein) load was studied. The influence of the critical parameters of electro-oxidation such as pH, period, salt concentration and current density on the reduction of organic load was studied using graphite electrodes. It was found that current density of 0.024 A/cm 2 for a period of 2 h at pH 9.0 rendered best results in terms of reduction in COD and TKN. The energy requirement for the reduction of 1 kg of TKN and 1 kg of COD are 22.45 kWh and 0.80 kWh respectively at pH 9 and 0.024 A/cm 2. Reuse experiments were conducted at commercial scale. One of the saline waste streams in leather manufacturing process, pickling was treated and reused continuously thrice. The characteristics of the waste stream and the quality of the leathers indicate that the reuse of saline streams with intermittent electrochemical treatment is feasible.

Production of basic chromium sulfate by using recovered chromium from ashes of thermally treated leather

Leather wastes tanned with chromium are generated during the production process of leather, hence the wastes from hand crafted goods and footwear industries are a serious environmental problem. The thermal treatment of leather wastes can be one of the treatment options because the wastes are rich in chromium and can be used as a raw material for sodium chromate production and further to obtain several chromium compounds. The objective of this study was to utilize the chromium from leather wastes via basic chromium sulfate production to be subsequently applied in a hide tanning. The obtained results have shown that this is the first successful attempt to achieve desired base properties of the product. The result was achieved when the following conditions were applied: a molar ratio between sodium sulfite and sodium dichromate equal to 6; reaction time equal to 5 min before addition of sulfuric acid; pH of sodium dichromate solution equal to 2. Summarizing, there is an opportunity to utilize the dangerous wastes and reused them in the production scheme by minimizing or annulling the environmental impact and to attend a sustainable process development concept.

Electrocoagulation efficiency of the tannery effluent treatment using aluminium electrodes

An electro-coagulation laboratory scale system using aluminium plates electrodes was studied for the removal of organic and inorganic pollutants as a by-product from leather finishing industrial process. A fractional factorial 2(3) experimental design was applied in order to obtain optimal values of the system state variables. The electro-coagulation (EC) process efficiency was based on the chemical oxygen demand (COD), turbidity, total suspended solid, total fixed solid, total volatile solid, and chemical element concentration values. Analysis of variance (ANOVA) for final pH, total fixed solid (TFS), turbidity and Ca concentration have confirmed the predicted models by the experimental design within a 95% confidence level. The reactor working conditions close to real effluent pH (7.6) and electrolysis time in the range 30-45 min were enough to achieve the cost effective reduction factors of organic and inorganic pollutants' concentrations. An appreciable improvement in COD removal efficiency was obtained for electro-coagulation treatment. Finally, the technical-economical analysis results have clearly shown that the electro-coagulation method is very promising for industrial application.

Ultrasound-aided leather dyeing: a preliminary investigation on process parameters influencing ultrasonic technology for large-scale production

The application of ultrasound to leather processing has a significant role for more efficient and advanced manufacturing techniques for leather production. The effect of important process parameters for scale-up such as mechanical agitation, float, and concentration of dye bath has been experimentally examined. The results indicate that float level and dye bath concentration has significant effect on exhaustion of dye. There is no appreciable improvement due to mechanical agitation over the effect of ultrasound in leather dyeing. Dyeing of chrome-tanned wet-blue leather has been carried out directly in the ultrasonic tank with larger area of sample for scale-up possibility. The results indicate notable improvement (1.6-fold) in dye exhaustion as compared to dyeing in process vessel immersed in the ultrasound tank. This is also equivalent to 4.3-fold increase due to ultrasound as compared to control process without ultrasound at static condition. Ultrasound-aided dyeing of vegetable-tanned (EI) leather shows sixfold improvement as compared to control process. Acoustic cavitation energy in the ultrasonic tank, another important parameter for the scale-up, has been measured and the results indicate that ~60% acoustic energy is absorbed by leather in the process. Influence of ultrasound on dye aggregate size, an important parameter for diffusion, was also studied and found to be beneficial. Different ultrasonic equipments such as ultrasonic tank or ultrasonic probe have been tested and compared for their efficacy. Mass balance for ultrasonic leather dyeing process was performed and compared with control processes. Preliminary techno economic cost benefit analysis indicates positive trend for ultrasonic dyeing as compared to conventional drumming process. Savings in dye due to the use of ultrasound yield significant profit taking into account of ultrasonic energy cost, with a payback period for ultrasonic equipment cost. Therefore, the use of ultrasound in leather processing is a potential viable option for tanners in near future as advanced technology.

Pollutant removal from tannery effluent by electrocoagulation

An electrocoagulation laboratory scale system was studied for the removal of organic and inorganic pollutants from a wastewater of leather finishing industrial process. In order to obtain optimal values of the system state variables, a fractional factorial 2 3 experimental design was applied. The electrocoagulation process response was evaluated on the basis of chemical oxygen demand (COD), turbidity, total suspended solid, total volatile solid, and elements concentration values. The interactions between initial pH and electrolysis time, as well as between initial pH and current density were significant only for the total chromium removal. The reactor working conditions close to natural effluent pH and electrolysis time in the range of 30–45 min were enough to achieve the cost-effective reduction of COD, turbidity and chromium concentrations. The electrocoagulation method has shown similar pollutant removal efficiencies when compared with the conventional one and can be used successfully for industrial applications. Based on its low operational cost, the electrocoagulation method could be recommended instead of the conventional one.

Kinetics of leather dyeing pretreated with enzymes: Role of acid protease

In the present investigation, kinetics of dyeing involving pretreatment with acid protease has been presented. Application of acid protease in dyeing process resulted in increased absorption and diffusion of dye into the leather matrix. Enzyme treatment at 1% concentration, 60 min duration and 50 °C resulted in maximum of 98% dye exhaustion and increased absorption rate constants. The final exhaustion ( C ∞) for the best fit of CI Acid Black 194 dye has been 98.5% with K and r 2 values from the modified Cegarra-Puente isotherm as 0.1033 and 0.0631. CI Acid Black 194 being a 2:1 metal complex acid dye exhibited higher absorption rate than the acid dye CI Acid Black 210. A reduction in 50% activation energy calculated from Arrhenius equation has been observed in enzyme assisted dyeing process of both the dyes that substantiates enhanced dye absorption. The absorption rate constant calculated with modified Cegarra-Puente equation confirm higher rate constants and faster kinetics for enzyme assisted dyeing process. Enzyme treated leather exhibited richness of color and shade when compared with control. The present study substantiates the essential role of enzyme pretreatment as an eco-friendly leather dyeing process.

Pembuatan kulit tahan air untuk bagian atas sepatu

The aim of research non manufacturing of waterproof leather for shoe upper is to find the best formula in producing waterproof cow hide leather for shoe uppers. Today, the tanners trying their best effort to fulfill the shoes. The research used salted raw cow hide 18 sides were utilized. Leather treatment process begining with soaking stage up to tanning stage and using the same formula in each treatment. In the fatliquoring stage, the treatment varied in the number of fatliquoring chemical material were 8,10, and 12 % respectively. Whereas, the amount of was silicon added in the dyeing process were 5,7.5, and 10 % respectively. The quality of the leather was physically examined accordance with testing method of ISO. 8782- 1998 € and DIN standard. The results performed that the best formula was sample with addition of fatliquoring 12 % and silicon5%.

Sustainable membrane-based process for valorisation of cork boiling wastewaters

Cork boiling wastewaters were processed by nanofiltration (NF) in order to concentrate phenolic compounds, whose tanning power allows their application in the leather tanning process as a retanning agent, and to produce a permeate suitable for reuse in the cork boiling operation, according to the International Code of Cork Stopper Manufacturing Practice. Four commercial polymeric membranes were selected and tested at laboratory scale: NTR7450, Desal-DK, NF90 and NF270. The feed volume reduction factor (VRF) was defined to be equal to seven or higher, and the operation was carried out in a batch mode at 15 bar and 25 ° C. The performance of the different membranes was evaluated determining membrane permeability and rejection coefficients for several pollutant indicators: total organic carbon (TOC), colour, absorbance at 254 nm and salt content. Two membranes were selected to perform pilot-scale studies, NF270 and NF90, based on their performance in this process. The results obtained in the laboratory and pilot-scale studies permitted the development of a mass balance model, which was calibrated with experimental data. Additionally, a technical and economical evaluation study was performed, which showed that the process proposed in this work is viable for industrial application.

The creation of leather fashion in Hong Kong

The main objective of this study was to determine a new model of design process of the Hong Kong leather fashion industry by employing a qualitative research approach and descriptive research design. The study provided some relevant literature about the development and sales channels of the Hong Kong leather fashion industry. A total of 24 fashion designers, sales and marketing managers and fashion educators were interviewed. The model of design process of the Hong Kong leather fashion industry was synthesised and combined from in-depth interviews of the respondents. The result of this study suggested that during the leather fashion design process, the major factors were the artistic value, marketability, consumer attitude and personal interests.

Proposal of wet blue leather remainder and synthetic fabrics reuse

This work presents the development of a leather remainder reuse process which consists of joining leather pieces into layers through the use of the hot melt technology. By using this process, it is possible to obtain some material which preserves the leather flexibility and strength properties. This innovative and incremental process aims at the remainder reuse which would normally be discarded. The great benefits of the hot melt applied to the leather remainders are as follows: skipping the barb cutting step, reducing time in the sewing process, and minimizing the impact on the environment.

An eco‐efficient rationalized leather process

AbstractBACKGROUND: The leather industry is under pressure to develop environmentally efficient leather‐making processes to comply with modern pollution and discharge legislation. Conventional leather‐processing methods are known to contribute significant pollution loads in tannery wastewaters. The rationalized process described here involves a salt‐free curing, lime and sulfide‐free beamhouse process and post‐tanning followed by tanning employing a reverse leather‐processing technique.RESULTS: Scanning electron microscopy (SEM) analysis substantiated that the grain surface, fibre separation and tight packing of fibres are similar for leathers from conventional and rationalized processes. The functional performance of the leathers is found to be on par with that of conventionally processed leathers. The rationalized leather process reduces the usage and discharge of chemicals by 68% and 82%, respectively. It also enjoys the reduction in biochemical oxygen demand (BOD), chemical oxygen demand, Cl−, SO42− and total solids loads by 58%, 62%, 95%, 66% and 85%, respectively. The rationalized process also results in reduction of water consumption and discharge and energy by 37%, 37% and 38%, respectively.CONCLUSION: The rationalized process utilizes resources efficiently with reduced environmental impact without compromising leather qualities and can be seen as being eco‐efficient compared to the conventional leather process. Copyright © 2007 Society of Chemical Industry