Bisphenol reduction in syntans and examples for extraction and migration of bisphenols from leather articles / Jochen Ammenn in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIX, N° 5 (05/2024)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIX, N° 5 (05/2024) Titre : Bisphenol reduction in syntans and examples for extraction and migration of bisphenols from leather articles Type de document : texte imprimé Auteurs : Jochen Ammenn, Auteur Année de publication : 2024 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Bisphénol F Bisphénol S Cuir Extraction (chimie) Produits chimiques -- Consommation -- Réduction Produits chimiques -- Migration Retannage Syntans Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Bisphenol S and F play a major role in the synthesis of syntans. Bisphenol S can be a starting material or undesired side product, while bisphenol F can form as an undesired side product. They can be found in basically all syntans in a range from close to the detection limit up to several thousand parts per million and can be detected in most leather articles by extraction or by migration. In an initiative by the European Chemicals Agency (ECHA) to drastically reduce bisphenols in consumer goods and in the environment, challenging limits were proposed in 2022. These limits would have had a strong impact on syntan portfolios of the leather chemical manufacturers and on many leather articles. After a public a consultation, ECHA has temporarily withdrawn the restriction proposal and wants to re-work it. Examples for reductions of both bisphenols in leather chemicals and the impact on extractions and migration from leather articles down to detection limits will be outlined in this article. Note de contenu : - Examples of bisphenol reductions in syntans - Extraction results of bisphenols from re-tanned leather - Migration results of bisphenols from leather re-tanned with syntans 2 and 2.LB - Table 1 : BPS and BPF in syntan 1 - Table 2 : Extraction from leathers made with 3 types of syntan 1 in re-tanning (6%) - Table 3 : Repeated extraction from leathers made with 6% syntan 1 in re-tanning - Table 4 : Extraction results from leathers made with phenolic syntan 2 and 3 in re-tanning ; values measured internal, as well as at the FILK (Freiberg) and PFI (Pirmasens) institutes - Table 5 : Results of BosC’s migration from leathers made with phenolic syntan 2 and 2.LB measured at PFI institute DOI : https://doi.org/10.34314/40d3q167 En ligne : https://drive.google.com/file/d/1W9ngTDzNHLbfF6xxpUF863GJD47DTsIk/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40977 [article]

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Chemistry of syntans and their influence on leather quality / Jochen Ammenn in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CX, N° 11 (11/2015)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CX, N° 11 (11/2015) . - p. 349-354 Titre : Chemistry of syntans and their influence on leather quality Type de document : texte imprimé Auteurs : Jochen Ammenn, Auteur ; C. Huebsch, Auteur ; E. Schilling, Auteur ; B. Dannheim, Auteur Année de publication : 2015 Article en page(s) : p. 349-354 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Syntans Tannage Tags : 'Tanins  synthétiques'  Formaldehyde  'Dihydroxy  diphényl  sulfone' Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The first syntan, Neradol D, was a condensate of phenolsulfonic acid and formaldehyde. While this chemistry allowed more efficient use of vegetable tannins, it was not advantageous to be applied on leather alone and has to be considered an auxiliary. Incorporating urea into the phenolsulfonic acid - formaldehyde condensation established a second generation of syntans with significantly improved lightfastness. Replacement syntans were developed to substitute vegetable tannins, giving rise to leathers of good softness and fullness. The formaldehyde condensation of dihydroxy diphenyl sulfone (sulfone) can be considered a further development of the replacement syntans with lower residual monomers. In order to compare these four generations of syntans, poly-condensates of a comparable molecular size had to be synthesized. These tested in hydrothermic denaturation of skin powder and applied in sole tanning and re tanning. The resulting leathers were compared in various aspects of performance including shrinkage temperature, softness, fullness, light fastness, and rest monomers. Note de contenu : - First and second generation syntans - Second generation syntans and replacement syntans - Replacement syntans and sulfone based syntans En ligne : https://drive.google.com/file/d/10X0FNheVCGQV9ejOTM0y9JZJc7GEv9qO/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=24863 [article]

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Melamine ethoxylates as novel formaldehyde free replacements of resin re-tanning agents / Jochen Ammenn in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVII, N° 7 (07/2022)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVII, N° 7 (07/2022) . - p. 296-301 Titre : Melamine ethoxylates as novel formaldehyde free replacements of resin re-tanning agents Type de document : texte imprimé Auteurs : Jochen Ammenn, Auteur Année de publication : 2022 Article en page(s) : p. 296-301 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Agents de tannage Cuirs et peaux de bovins Ethoxylates de mélamine Formaldéhyde -- Suppression ou remplacement Produits de condensation (chimie) Retannage Tannage synthétique Wet-blue (tannage) Peau tannée au chrome (le chrome donne une couleur bleue) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Melamine urea formaldehyde condensates or resin re-tanning agents are commonly used in the leather industry. They give rise to homogeneous filling, are easily and widely applicable, but generally contribute to free formaldehyde, measurable in emission or extraction methods. Many projects to resolve this issue have been carried out. The weakness of the resin re-tanning is the reversibility of the bond formation between formaldehyde and two amino groups. The formaldehyde forms a methylene group after condensation with two amino groups and releases water. This methylene group can be hydrolyzed under acidic conditions to release formaldehyde again, reversing the synthesis. Melamine ethoxylates were found to be a formaldehyde free, stable, and easily applicable alternative. Besides the fact that they are made without formaldehyde, it proved to be possible to incorporate renewable components into their synthesis, giving rise to an even more sustainable product. Another sustainable aspect of this chemistry is the delivery of the potential product as a concentrated liquid versus most resin re-tanning agents being placed into the market as spray dried powders, consuming significant amounts of energy in the process. Melamine ethoxylates show advantages in application on leather in comparison with classical resin re-tanning agents. An insight into the scope of application will be given, showing that melamine ethoxylates can be considered a formaldehyde free replacement for resin re-tanning agents. Note de contenu : - Melamine urea formaldehyde condensates - Melamine ethoxylates - Table 1 : Screening results of the re-tanning of bovine wet blue of different melamine ethoxylates against a standard melamine urea formaldehyde condensate and polyethylene glycol : + = better ; 0 = similar ; — = worse - Table 2 : Re-tanning of bovine wet blue with the optimized melamine ethoxylate against a standard melamine urea formaldehyde condensate : + = better; 0 = similar ; - = worse - Table 3 : Results of re-tanning of bovine wet blue or wet white with melamine ethoxylates in a mixed recipe compared to a melamine urea formaldehyde condensate in the mixed recipe : + = better; 0 = similar; - = worse En ligne : https://drive.google.com/file/d/1cuWtS0wR-6zJregVnQ4eK0FqHZOfhLNC/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37822 [article]

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Recent findings in acetaldehyde emission from leather / Jochen Ammenn in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXII, N° 8 (08/2017)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXII, N° 8 (08/2017) . - p. 259-262 Titre : Recent findings in acetaldehyde emission from leather Type de document : texte imprimé Auteurs : Jochen Ammenn, Auteur ; Brigitte Wegner, Auteur ; B. Dannheim, Auteur Année de publication : 2017 Article en page(s) : p. 259-262 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Composés organiques volatils Cuir dans les automobiles Cuirs et peaux -- Analyse Ethanal L'éthanal (Nomenclature IUPAC), aussi appelé acétaldéhyde, aldéhyde acétique, éthyl aldéhyde ou oxoéthane, est un composé chimique, un aldéhyde de formule chimique CH3CHO. Naturellement produit par les plantes, c'est un composant volatil trouvé à faibles doses dans les fleurs et feuilles du coton, dans les feuilles de chêne et de tabac, dans les fruits mûrs, le café et le pain frais. Il contribue à l’odeur du romarin, des jonquilles, de l’orange amère, du camphre, du fenouil, de la moutarde et de la menthe. Il servait autrefois de matière première de base pour la synthèse de l’acide acétique et de l’anhydride acétique. Il est utilisé comme agent de sapidité dans certaines margarines. C'est un produit toxique et cancérigène suspecté. L'éthanal est un liquide incolore, volatil et miscible à l'eau et à presque tous les solvants organiques. L'odorat humain le perçoit à très faible dose (0,05 ppm suffisent) comme une odeur fruitée (pomme verte) et il devient suffocant et piquant à forte teneur. Il est très réactif et inflammable (point d'ébullition: 20,2 °C). Il peut vivement réagir avec, par exemple, des oxydants, halogènes , ammoniac et amines, alcools, cétones, phénols, anhydrides d'acide, sulfure d'hydrogène, cyanures. En contact avec le cuivre ou des alliages en contenant (bronze, laiton, ...), il peut former des composés explosifs. Il ronge le caoutchouc. Comme tous les aldéhydes, c'est un réducteur. Son oxydation, très facile puisqu'elle peut même se produire au contact de l'air, donne de l'acide acétique, de l'anhydride acétique et de l'acide peroxyacétique instable susceptible de spontanément exploser. L'hydrogénation de l'éthanal donne de l'éthanol. Trois molécules d'acétaldéhyde peuvent former un paraldéhyde cyclique. Quatre molécules d'acétaldéhyde peuvent former un tétramère d'acétaldéhyde cyclique, le métaldéhyde. Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Acetaldehyde emissions are a significant challenge for automotive leather producing tanneries. This is especially true to meet the requirements for the Chinese market. Unlike formaldehyde, acetaldehyde is not used as a building block of tanning agents or auxiliaries and has rarely been traced in extraction assays in which the detection medium is water. However, it contributes to significant problems in emission tests for leathers in which the molecules are detected in the air. Until recently, few data points on acetaldehyde emissions were available, mostly on finished leather. In this publication, our new, facile method for the measurement of acetaldehyde emission will be introduced, evaluated, and exemplified with data across the whole process of leather making, from beam house to finished leather. With our new method we could show that the emissions generally decrease from skin to crust. Biochemical background for the high levels of acetaldehyde in skin will be given. Through the application of suitable scavengers, acetaldehyde emissions could be reduced significantly in automotive leathers. Note de contenu : - SCHEME : Acetaldehyde determination in a rotation evaporator - FIGURES : 1. Degradation of threonine - 2. Acetaldehyde emission in five stages of the leather making process - 3. Acetaldehyde emission from finished leather over a time of ten month - 4. Acetaldehyde emission from wet blue and wet white - 5. Glutaraldehyde competes with an acetaldehyde (in red) being bound to a lysine via imine bond - 6. Scavenging of acetaldehyde with DNPH and acetylacetone - 7. Scavening of acetaldehyde in wet end and finishing - 8. Acetaldehyde emissions in leather process compared to apples and raspberries En ligne : https://drive.google.com/file/d/1_etRigilu7gR0ykb9QCosnQK-zmQdxY_/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=28824 [article]

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