Rapid oxidative dehairing with magnesium peroxide and potassium peroxymonosulfate / Andrew G. Gehring in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CI, N° 9 (09/2006)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CI, N° 9 (09/2006) . - p. 324-329 Titre : Rapid oxidative dehairing with magnesium peroxide and potassium peroxymonosulfate Type de document : texte imprimé Auteurs : Andrew G. Gehring, Auteur ; William N. Marmer, Auteur ; Chad E. Mazenko, Auteur ; Robert L. Dudley, Auteur Année de publication : 2006 Article en page(s) : p. 324-329 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Sodium sulfide is traditionally used to remove hair from animal hides during tanning operations. However, alternatives to sodium sulfide are desired because sodium sulfide is an environmental pollutant that is quickly converted to highly toxic hydrogen sulfide gas if accidentally exposed to acid. In past research, we demonstrated that either alkaline calcium peroxide or alkaline hydrogen peroxide may be used as an effective substitute for concentrated sodium sulfide for rapid dehairing. More recently, we demonstrated the effectiveness of alkaline hydrogen peroxide with potassium cyanate. Here we similarly present alternative oxidative dehairing reagents/conditions, using magnesium peroxide and potassium peroxymonosulfate, which may also find application in either the packing plant or beamhouse. As observed with previously reported rapid dehairing, dehairing often is not thorough, leaving very short stubble. However, residual hair was readily removed with a sodium sulfide sharpening/hairburn, indicating that hair stubble was not immunized by the oxidative treatment. Dehairing reaction conditions that rapidly removed 80% or greater of hair from cattle hide pieces were observed for magnesium peroxide (5%, 15% NaOH, 200% float, 45°C, 8 min, hairburn process) and potassium peroxymonosulfate (5%, 15% NaOH, 200% float, 45°C, 7 min, hairburn process). Leather produced from matched side pieces that were subjected to these oxidative dehairing treatments was determined to take up less chromium yet was tougher than leather produced using conventional hairburn with sodium sulfide. Other physical testing results are also reported. En ligne : https://drive.google.com/file/d/187W3ZURmZXXDSwg5-Ulz-bJ-XteOfmY2/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3991 [article]

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Rapid oxidative unhairing with alkaline calcium peroxide / Andrew G. Gehring in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 6 (06/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 6 (06/2003) . - p. 216-223 Titre : Rapid oxidative unhairing with alkaline calcium peroxide Type de document : texte imprimé Auteurs : Andrew G. Gehring, Auteur ; David G. Bailey, Auteur ; Gary L. DiMaio, Auteur ; Robert L. Dudley, Auteur ; William N. Marmer, Auteur ; Chad E. Mazenko, Auteur Année de publication : 2003 Article en page(s) : p. 216-223 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Sodium sulfide is frequently used to remove hair from animal hides during tanning operations. However, since sodium sulfide is an environmental pollutant that is quickly converted to highly toxic hydrogen sulfide gas if accidentally exposed to acid, an alternative unhairing agent is desired. We have observed that calcium peroxide may be used to rapidly unhair cattle hides with efficiency similar to that of sodium sulfide. Under alkaline conditions (pH ~13), 5-15 % (w/w) calcium peroxide mixture applied in two back-to-back applications, afforded either complete or nearly complete unhairing within 10 minutes of total reaction time at a reaction temperature of ~45°C. Most of the removed hair was essentially broken down or dissolved in this rapid oxidative hairburn process. Alternatively, intact, long strands of hair could be removed and recovered (hairsave) with a single application of the calcium peroxide solution (solids removed) followed by rapid adjustment of the hair solids to an approximately neutral pH. However, hair stubble remained on the hide after subjected to this latter hairsave process. The alkaline calcium peroxide hairburn and hairsave processes were studied using hide pieces (laboratory-scale experiments) and matched sides (pilot-scale experiments) and compared to conventional hairburn with sodium sulfide. The studies revealed that shrinkage temperature, physical testing, dye shading, dye levelness and grain appearance were comparable. In addition, several commercially available non-sulfide sharpening agents, added during reliming of hide pieces, were demonstrated to remove residual hair stubble that remained after rapid oxidative hairburn. En ligne : https://drive.google.com/file/d/1IHk1VAMX6HZM61vQsuat_uami76ko9cI/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4139 [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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