Research Institute of Leather and Plastic Sheeting

Freiberg, Germany

Research Institute of Leather and Plastic Sheeting

Freiberg, Germany
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Schropfer M.,Research Institute of Leather and Plastic Sheeting | Czerny M.,German Research Center for Food Chemistry | Schulz H.,Research Institute of Leather and Plastic Sheeting | Schieberle P.,Fraunhofer Institute for Process Engineering and Packaging
Journal of the American Leather Chemists Association | Year: 2013

Leather has a typical odor that varies depending on the type of leather. Whereas many other materials should preferably be odorless, a typical leather odor is desired. It is an important quality feature. So far the compounds causing the leather odor could not be clearly defined. For this research work, different leathers from different application areas were chosen. Depending on the manufacturing technology the leathers showed different nuances of leather odor. Published herein are the results from analysis of leathers by GaschromatographyOdorimetry (GC-O), Aroma-extract-dilution analysis (AEDA), Gas chromatography-Mass-Spectrometry (GC-MS) and Stable-Isotope-Dilution-Analysis (SIDA) for identifying and quantifying substances accountable for certain leather odors. Furthermore, it points out from which stages of leather manufacturing the leather odor originates and if it can be influenced. Alternative methods for identification and quantification of substances relevant to odor are discussed regarding their significance.

Souza F.,Federal University of Rio Grande do Sul | Meyer M.,Research Institute of Leather and Plastic Sheeting | Wulf H.,Research Institute of Leather and Plastic Sheeting | Klover E.,Research Institute of Leather and Plastic Sheeting | And 2 more authors.
XXXIII IULTCS Congress | Year: 2015

The high organic load of unhairing wastewater from leather processing is mainly caused by dissolved hair. However, this keratin-rich material can be recovered if it is not degraded completely in the course of the liming step. This study features the hydrolysis of keratin from bovine hair before and after treatment in seven different chemical solutions. The raw material was obtained by a hair-saving unhairing process, recovered from waste and from natural trimmed hairs respectively. We show here that it is possible to recover proteins with molecular weights around 20 kD are using this hair waste. Applying hydrogen peroxide during hydrolysis procedure, approximately 75 % of the protein can be recovered and up to 90 % yield can be reached when sodium sulfide is used in a reductive pathway.

Gillen S.,TU Munich | Gillen S.,Research Group MITI | Grone J.,Charite Campus Benjamin Franklin | Knodgen F.,Research Group MITI | And 8 more authors.
Surgical Endoscopy and Other Interventional Techniques | Year: 2012

Background: Natural orifice translumenal endoscopic surgery (NOTES) is a new surgical concept that requires training before it is introduced into clinical practice. The endoscopic-laparoscopic interdisciplinary training entity (ELITE) is a training model for NOTES interventions. The latest research has concentrated on new materials for organs with realistic optical and haptic characteristics and the possibility of high-frequency dissection. This study aimed to assess both the ELITE model in a surgical training course and the construct validity of a newly developed NOTES appendectomy scenario. Methods: The 70 attendees of the 2010 Practical Course for Visceral Surgery (Warnemuende, Germany) took part in the study and performed a NOTES appendectomy via a transsigmoidal access. The primary end point was the total time required for the appendectomy, including retrieval of the appendix. Subjective evaluation of the model was performed using a questionnaire. Subgroups were analyzed according to laparoscopic and endoscopic experience. Results The participants with endoscopic or laparoscopic experience completed the task significantly faster than the inexperienced participants (p = 0.009 and 0.019, respectively). Endoscopic experience was the strongest influencing factor, whereas laparoscopic experience had limited impact on the participants with previous endoscopic experience. As shown by the findings, 87.3% of the participants stated that the ELITE model was suitable for the NOTES training scenario, and 88.7% found the newly developed model anatomically realistic. Conclusions: This study was able to establish face and construct validity for the ELITE model with a large group of surgeons. The ELITE model seems to be well suited for the training of NOTES as a new surgical technique in an established gastrointestinal surgery skills course. © Springer Science+Business Media, LLC 2012.

Gunther S.,Fraunhofer Institute for Mechanics of Materials | Teuscher N.,Fraunhofer Institute for Mechanics of Materials | Heilmann A.,Fraunhofer Institute for Mechanics of Materials | Hansel R.,Research Institute of Leather and Plastic Sheeting | And 2 more authors.
Journal of Adhesion Science and Technology | Year: 2011

Atmospheric pressure plasma discharges are often used to modify surfaces of polymer films due to their excellent ability to be integrated in the manufacturing line. The plasma treatment leads to surface activation and is employed to improve printability or adhesion. These effects are well known, however there is a necessity for a process control to prove the efficiency and the homogeneity of the modification, and furthermore to have a method to ensure quality requirements or for the description of the complex modification processes. In this study, optical emission spectroscopy was utilized to investigate the plasma of a dielectric barrier discharge used for treating polyethylene films. The aim was to find correlations between both the influences of plasma parameters as well as the reactions in the plasma and the resulting surface properties. The surface modifications were analyzed by contact angle measurements and X-ray photoelectron spectroscopy (XPS). © 2011 Koninklijke Brill NV, Leiden.

Stenzel S.,Research Institute of Leather and Plastic Sheeting | Bohrisch J.,Fraunhofer Institute for Applied Polymer Research | Pach M.,UP Transfer GmbH | Meyer M.,Research Institute of Leather and Plastic Sheeting
Journal of the American Leather Chemists Association | Year: 2015

The use of synthetic DNA as a marking system is a new traceability concept in the leather industry, especially for supplier and batch tracing. DNA is outstandingly suited for the usage as a marking system because of its code diversity, invisibility and doubtlessness. However, DNA labeling is a great challenge for products exposed to DNA damaging influences during their production, such as acidic pH, elevated temperatures in combination with high humidity or sunlight radiation. Leather is such a product. We attached single-strand DNA (ssDNA) to hydroxyapatite and enhanced the stability of these DNA particles by encapsulation in polystyrene-co-divinylbenzene (PS-DVB) microcapsules. Furthermore, the ssDNA containing microcapsules were improved with functional groups on the surface of the capsule to irreversibly attach them to the collagen matrix of leather by chrome tanning. Laboratory scale tests using acidic conditions as well as elevated temperatures in the presence of high humidity showed that the stability of the leather marking system was enhanced. Marking trials were conducted in crust leathers, and the light fastness of these labeled crusts were tested. The results indicate that encapsulated DNA-hydroxyapatite-particles are more stable at sunlight radiation than non-encapsulated DNA. These marking trials showed that the system could be a suitable leather marking system in the leather industry to establish a powerful supplier and batch tracing.

Schroepfer M.,Research Institute of Leather and Plastic Sheeting | Meyer M.,Research Institute of Leather and Plastic Sheeting
XXXIII IULTCS Congress | Year: 2015

The mode of interaction of vegetable tanning agents with skin collagen is hardly to predict due to the variability of chemical interactions of the vast number of different substance classes. The present study introduces low effort methods in order to classify the cross-linking action of vegetable and synthetic agents. The mode of interaction is classified in three different groups that are ionic (reversible interaction), covalent (non-Acid-resistant interaction) and covalent (acid-resistant interaction). As testing material untanned hide powder is used, hence diffusion effects are excluded and the determined parameters strictly reflect the binding actions. The pH causes changes in the charge state of the collagen's amino acid side chains which influences the binding of certain tanning agents. Therefore, the cross-linking experiments are performed at changing but defined pH conditions. To learn more about the mode, strength of cross-linking and groups involved depending on the pH, the denaturation temperature, amino acid composition and resistance to proteolysis are analyzed. Many of common vegetable tanning extracts where classified according to their mode of interaction. The tanning action of new plant extracts of local wide spread plants have been classified and characterized in terms of their reaction mechanism. Additionally, for the development of vegetable leather tanning or retanning-processes these methods can be applied in order to improve the process management, particularly the pH-management.

Trommer K.,Filk gGmbH | Trommer K.,Research Institute of Leather and Plastic Sheeting | Morgenstern B.,Filk gGmbH
Coating International | Year: 2010

Thin silicone membranes were used as barrier layer for textile laminates due to excellent material properties. Suitable compositions for silicone resins were developed at the FILK gGmbH, based on which thin membranes were produced. Production and processing were possible without protective foil and an appropriate adhesive system on silicone basis was found, which enabled lamination of these silicone membranes with PES textiles. The membranes were processed with laminar textiles, using adhesives on silicone basis. The adhesive was applied in holohedral and dot bonding processes and PES-based textiles were used for producing textile laminate systems due to the necessary vulcanization temperature of up to 180 °C.

Stenzel S.,Research Institute of Leather and Plastic Sheeting | Bohrisch J.,Fraunhofer Institute for Applied Polymer Research | Meyer M.,Research Institute of Leather and Plastic Sheeting
Journal of Applied Polymer Science | Year: 2015

The usage of synthetic single-strand DNA (ssDNA) as an invisible barcode is critical for products, which are exposed to DNA damaging influences during their production or handling (ultraviolet light, acidic conditions, and high temperatures). Encapsulation may protect ssDNA against hydrolytic attack under acidic conditions. This assumption was proved by embedding ssDNA into a spherical hydrogel matrix of polyacrylamide and coating it with a crosslinked polystyrene shell. After acidic treatment of these capsules, the ssDNA stability was measured by detecting the amplification ratio over time with quantitative real-time polymerase chain reaction and calculating the apparent rate constant and apparent half-life. The results of the quantitative detection of ssDNA damage demonstrated that enhancing ssDNA stability by encapsulation with crosslinked polystyrene is possible. Such a potential application may be used in all fields of traceability and of combating counterfeiting, where protection of DNA against environmental influences is needed, for example, as safe marking system for paper, biomaterials, textiles, or leather. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41754. © 2014 Wiley Periodicals, Inc.

Trommer K.,Research Institute of Leather and Plastic Sheeting | Morgenstern B.,Research Institute of Leather and Plastic Sheeting
Journal of Applied Polymer Science | Year: 2010

The non-rigid microporous PVC films are prepared by mono-axially stretching nonporous sheets containing fillers which show an average particle size of 2to10 im. The nonporous PVC film is generated from paste-like PVC. The influence of recipe components on the mechanical properties, morphological behavior and permeability to water vapor and water was investigated as well as the influence of the stretching ratio. Filled PVC pastes exhibit higher values for viscosity than those of pure polymer mixtures. For processing the compounded paste by means of a doctor blade a low viscosity is required meaning the amount of filler is limited by the resulting paste viscosity. Due to dewetting, the filler initiates the holes of the microporous system during the stretching process. Empirically, a minimum of about 15 vol % filler particles are necessary in order to achieve an interconnected air hole system. Varying the components PVC, plasticiser and filler, PVC membranes could be prepared with high water vapour permeability and high waterproofness simultaneously. To utilize the membranes commercially a continuous preparation process was developed. © 2009 Wiley Periodicals, Inc.

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