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Staking and its interaction with fatliquoring on vacuum-dried leather / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 9 (09/2002)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 9 (09/2002) . - p. 329-338 Titre : Staking and its interaction with fatliquoring on vacuum-dried leather Type de document : texte imprimé Auteurs : Cheng-Kung Liu, Auteur ; Nicholas P. Latona, Auteur ; Gary L. DiMaio Année de publication : 2002 Article en page(s) : p. 329-338 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Staking is one of the key leather making operations to soften leather and to improve its pliability. Besides the number of staking passes, there are many other factors affecting the action of staking, and consequently theresultant physical properties of staked leather. Fatliquoring, for example, is another process to soften leather and will influence the results of staking. There is no report so far, however, to demonstrate the interaction of fatliquoring and staking on softening leather. This investigation is devoted to this important subject, aiming at a better understanding of their interaction on pliability and other important properties of concern to the leather industry, such as mechanical strength, elongation, toughness and area retention. We therefore have conducted a systematic study, using the SAS statistical program, to formulate their interactive relationship on the physical properties of leather. Observation showed that the tensile strength and tear strength both increase steadily with increasing number of staking passes. This trend slowly reverses, however, as the fatliquor concentration increases. Even more intricate is the effect of fatliquor on the behavior of staking softening. Without fatliquor, staking actually stiffens the leather. Data showed the softening action of staking only becomes effective after fatliquor concentration reaches a certain level. Area measurements showed no obvious link between the amount of staking and area retention. An association was observed, however, between the residual water content and area retention. The leather after vacuum drying with less residual water content shows better area yield. En ligne : https://drive.google.com/file/d/1e75Zbd7iagogR-f6nh2HL_sp5nodnkgb/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4270 [article]

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Improved hide quality and rapid unhairing / Andrew G. Gehring in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 9 (09/2002)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 9 (09/2002) . - p. 339-348 Titre : Improved hide quality and rapid unhairing Type de document : texte imprimé Auteurs : Andrew G. Gehring, Auteur ; David G. Bailey, Auteur ; Gary L. DiMaio, Auteur Année de publication : 2002 Article en page(s) : p. 339-348 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The quality of hides suffers from their treatment by the packing industry as a byproduct, at best, of meat production. A meat packing company, Future Beef Operations, LLC (FBO), is changing this mentality by developing a vertically integrated cattle operation in which the hide is a product in its own right. A key component of this innovative operation is the rapid unhairing of stunned cattle carcasses prior to flaying in the slaughterhouse. Since it removes hair-associated manure, dirt, and microorganisms, rapid unhairing greatly reduces the cross-contamination of microorganisms on the hide to the meat, thus serving as a food safety measure while allowing for the rapid grading of hide quality and cost savings in downstream tanning operations. Under a cooperative agreement, Agricultural Research Service and FBO developed an effective rapid unhairing process based upon the earlier work (in 1977) by R. Dorstewitz on a rapid through-feed unhairing system. The rapid unhairing process was refined whereupon optimal conditions included 6.2% sodium sulfide at 35°C applied as a pressurized spray (in two applications) to warmed hide piece samples; an additional spray application of the sodium sulfide was used to remove the partially dissolved hair from the samples and subsequent neutralization of residual sulfide (still on the sample pieces) with 3% hydrogen peroxide was brought about in less than 5 min of total reaction time. The process sufficiently removed hair and hide-associated manure balls, allowing for splitting of green hide. The process was further developed to incorporate the recycling of the unhairing agent (sodium sulfide) and recovery of removed hair. Analysis of the recycled unhairing solution over 16 cycles showed a linear consumption of ca. 20% sulfide with a linear gain of ca. 1% nitrogen (proportional to dissolved hair protein content). En ligne : https://drive.google.com/file/d/1tCGNdYBGlDCDLOD8F1lGYsQdFLfpdSo7/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4271 [article]

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Deproteination of chrome waste by washing and enzymatic hydrolysis / J. Kupec in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 9 (09/2002)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 9 (09/2002) . - p. 349-354 Titre : Deproteination of chrome waste by washing and enzymatic hydrolysis Type de document : texte imprimé Auteurs : J. Kupec, Auteur ; M. Dvorackova, Auteur ; S. Rudlova, Auteur ; J. Ru, Auteur ; Karel Kolomaznik, Auteur Année de publication : 2002 Article en page(s) : p. 349-354 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Waste from the manufacture of chrome-tanned leathers (so-called shavings) can be processed (apart from alkaline or acid breakdown) by enzymatic hydrolysis employing alkaline proteases. Under mild reaction conditions, a soluble collagen hydrolyzate is formed and a solid fraction (so-called chrome cake) with high chromium content is formed after filtration. Further use of the chrome cake, e.g., tanning bath recycling, necessitates a maximum possible reduction in the protein fraction. This work performed deproteination of the chrome cake by decantation washing with water and enzymatic hydrolysis. Decantation washing of the chrome cake obtained after two-stage enzymatic hydrolysis of chrome-tanned shavings was performed six times with drinking water at laboratory temperature. A reduction in protein content occurs, as was proved by chemical analysis of chrome cakes prior to and after washing. Further deproteination of the chrome cake so washed (hence disposed of soluble part) was executed by means of additional enzymatic hydrolysis with ESPERASE and TRYPSIN. It was proved that further deproteination of chrome cake proceeded from this treatment even under very low concentrations of enzymes. En ligne : https://drive.google.com/file/d/19x9BcSXr3A1IglN1MkY0g87ql7pSMZaA/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4272 [article]

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Lubrication of leather with polyethylene glycol / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 9 (09/2002)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 9 (09/2002) . - p. 355-368 Titre : Lubrication of leather with polyethylene glycol Type de document : texte imprimé Auteurs : Cheng-Kung Liu, Auteur ; Nicholas P. Latona, Auteur ; Gary L. DiMaio, Auteur Année de publication : 2002 Article en page(s) : p. 355-368 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : One of the problems associated with leather quality is that traditional lubricants ("fatliquors" consisting of oils and surfactants) are known to destabilize collagen fibers. Moreover, because they do not promote the retention of essential moisture, they make the leather fibers prone to over-drying. We have recently applied an aqueous solution of low molecular weight polyethylene glycol (PEG 400) to leather without using any surfactants. The resultant stiffness was characterized by Young's modulus, initial strain energy and acoustic emission methods. Results showed that leather treated with polyethylene glycol solutions showed a significant reduction in its stiffness, indicating that PEG has a lubricating effect in leather. Efforts were also made to understand how factors affect the absorption of PEG into leather. Observations showed that the rate of absorption is not constant; therefore Fick's second law of diffusion, dealing with unsteady state processes, was employed to derive a mathematical model for the absorption rate. The effect of temperature on the absorption rate was also included in the model by incorporating a linear equation into Fick's diffusion equation. The resultant model fits the experimental data very well. It not only depicts the mechanism of absorption, but also predicts the absorption rate as a function of key variables. En ligne : https://drive.google.com/file/d/1pYs6OycSeNTM-L_VadJ3MUcEyLkFxyi7/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4273 [article]

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