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Area retention studies for vacuum-dried leather / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 10 (10/2002)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 10 (10/2002) . - p. 381-388 Titre : Area retention studies for vacuum-dried leather Type de document : texte imprimé Auteurs : Cheng-Kung Liu, Auteur ; Gary L. Di Maio, Auteur ; Nicholas P. Latona, Auteur Année de publication : 2002 Article en page(s) : p. 381-388 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The importance of knowing the effect of leather making conditions on the resultant area yield cannot be over-emphasized because the price of a piece of chrome-tanned leather is determined by its area. In our previous vacuum drying studies, we demonstrated that the residual water content is the key factor governing area retention. However this general doctrine can be complicated by additional variables such as the initial water content and the number of staking passes, particularly for the toggled-dried leather because of the mechanical stretch that occurs. We therefore have conducted a systematic study focusing on four factors simultaneously: initial water content, fatliquor concentration, drying time and the number of staking passes. We used the SAS statistical program to formulate their interactive relationship on the area retention of leather. A second order polynomial regression equation was derived to plot 3-D response surfaces that clearly illustrate the relationship between the variables and area retention. Observation showed that the area retention increases steadily with increasing either initial water content or fatliquor concentration. This trend slowly reverses, however, as both of these factors increase further. The effect of staking on area retention is also very intricate. Without the proper amount of fatliquor or initial water content, staking can significantly reduce area retention. This investigation has attained comprehensive information of the effects of these four variables and more importantly their interactions on area retention. En ligne : https://drive.google.com/file/d/1-neAIadhNWTEOZThjbqG60UxFj2c_JBI/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4247 [article]

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Acoustic emission studies for leather coatings / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 10 (10/2002)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 10 (10/2002) . - p. 389-399 Titre : Acoustic emission studies for leather coatings Type de document : texte imprimé Auteurs : Cheng-Kung Liu, Auteur ; Gary L. DiMaio, Auteur ; Nicholas P. Latona, Auteur Année de publication : 2002 Article en page(s) : p. 389-399 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Finishing, the final step in the leather-making process, contributes to the beauty and durability of leather. Choosing the right coating is critical in obtaining a satisfactory finishing result, such as good flexing endurance and no surface cracking. Acoustic emission has been known to be a useful method to characterize the coating properties for the automobile industry. As a continuation of our efforts to investigate the applications of acoustic emission technology to leather manufacture, we exploited the AE technique to measure the flexing endurance of leather coatings. An acoustic sensor was clipped to the grain layer of finished leather in a tensile test to collect various acoustic quantities. Observations showed that differences in the flexibility of the coatings can be analyzed by examining the plot of the AE count rate as a function of time. We have concluded that a quantitative association exists between the flexibility of coatings and the cumulative acoustic counts produced at an initial tensile stretch. The results of this AE research may provide a route to examine the flexing endurance of leather coatings. En ligne : https://drive.google.com/file/d/17XHDAPdWdQ7O00GaBVyeWxcxXqZAELad/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4267 [article]

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Retanning of goatskin using aldehyde after tanning with chromium salts / A. L. F. De Brito in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 10 (10/2002)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 10 (10/2002) . - p. 400-405 Titre : Retanning of goatskin using aldehyde after tanning with chromium salts Type de document : texte imprimé Auteurs : A. L. F. De Brito, Auteur ; A. C. S. Muniz, Auteur ; S. Prasad, Auteur Année de publication : 2002 Article en page(s) : p. 400-405 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The leather production for footwear of goat origin using trivalent chromium salts and subsequent retanning with aldehyde needs a detailed study of physico-mechanical characteristics. This work evaluates the physico-mechanical aspects of leather treated with trivalent chromium and retanned with aldehyde. The experiment was conducted in an entirely randomized manner with three treatments and three replications, applying different percentages of chromium (treatment A 1.5%, B 3.0%, and C 4.5%). There was a significant difference in tear and tensile strengths at 5% of probability by the test of Tukey, indicating that the percentage of chromium used in rechroming influenced the tear and tensile strengths of the leather produced. The goat leather obtained for footwear presented excellent softness, grain fineness and touch indicating that the combination of aldehyde and chromium salts, can be applied in production of footwear articles. En ligne : https://drive.google.com/file/d/1HZid6vwOBgldxw02ok1i9m6XgV1x5X03/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4268 [article]

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Unhairing with proteolytic enzymes derived from Streptomyces griseus / Andrew G. Gehring in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 10 (10/2002)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 10 (10/2002) . - p. 406-411 Titre : Unhairing with proteolytic enzymes derived from Streptomyces griseus Type de document : texte imprimé Auteurs : Andrew G. Gehring, Auteur ; Chad E. Mazenko, Auteur ; William N. Marmer, Auteur ; Gary L. DiMaio, Auteur Année de publication : 2002 Article en page(s) : p. 406-411 Note générale : Bibliogr. Langues : Américain (ame) Résumé : A mixture of proteolytic enzymes derived from the bacterium, Streptomyces griseus, was used to unhair bovine hide pieces. The enzymatic unhairing was assisted by a 30-min pretreatment of the pieces with carbonate buffer and the inclusion of a common amphoteric surfactant (N, N-dimethyl-1-dodecanamine oxide) in the enzyme formulation. This unhairing process may serve as a replacement for the hairburn process that relies on hazardous sodium sulfide. The unhairing reaction consisted of drumming pretreated hide pieces with 0.5 mg/mL of the bacterial protease (in 1% N, N-dimethyl-1-dodecanamine oxide) for 4 hours at 37°C in a 200% float. This process causes the majority of hair to either fall out intact or to become extremely loose and hence readily removed through physical/mechanical means. Some fine hairs remain, thus requiring sharpening agents to be used in reliming to achieve total unhairing. Laboratory-scale studies using bovine hide pieces compared this enzymatic treatment to typical hairburn with sodium sulfide. The studies demonstrated that shrinkage temperature, physical properties, dye levelness, dye shading, and grain appearance were comparable if not better for the enzymatic unhairing. En ligne : https://drive.google.com/file/d/1TxoucXpfszNDUxQTkZ1Z0qx7a_eFHY80/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4269 [article]

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