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Poređenje fizičko mehaničkih svojstava hromno i biljno štavljene kože
Comparison of physical and mechanical properties of chrome and vegetable tanned leather
aUniverzitet u Banjoj Luci, Tehnološki fakultet, Republika Srpska, BiH bUniverzitet u Banjoj Luci, Tehnološki fakultet, Republika Srpska, BiH + Zavod IRCUO, Žiri, Slovenia
e-adresa: sara.lakic@tf.unibl.org, tatjana.botic@tf.unibl.org, aleksandra.sinik@tf.unibl.org, novak.bostjan@tf.unibl.org, svjetlana.janjic@tf.unibl.org
Projekat: This work was supported by European Union, Erasmus+ project: FOOTWEAR FAST FORWARD COOPERATION - Innovative agile training program and training opportunities for the digital and green twin transition in Bosnia (3F-COOP, Project No. 101129078)
Ključne reči: koža; hromom štavljena; biljno štavljena; čvrstoća na kidanje
Keywords: leather; chrome-tanned; vegetable-tanned; breaking strength
Sažetak
Process prerade kože je veoma dug i sastoji se od mnogo različitih hemijskih i mehaničkih operacija. Najvažnija operacija u procesu prerade kože je štavljenje, koje se najčešće izvodi biljnim ili hromnim štavilima. Ovim radom želeli smo da uspostavimo vezu između načina štavljenja kože i njenih fizičko-mehaničkih svojstava. U tu svrhu ispitvana su određena fizičko-mehanička svojstva goveđe, ovčije i kozije kože, koje su dobijene hromnim ili biljnim štavljenjem. Ispitivanja su izvođena na komercijalno dostupnim kožama. Na odabranim uzorcima kože ispitivani su: debljina, površinska masa, prividnu gustina, prekidna sila i prekidno izduženje, dok su druge veličine izračunate na osnovu prethodno izmjerenih vrijednosti. Nakon mjerenja, rezultati su upoređeni prema vrsti kože i metodi štavljenja. Dobijeni rezultati su pokazali bolja fizičko-mehanička svojstva hromno štavljenih koža u poređenju sa biljno štavljenim, sa najvećom prekidnom jačinom hromno štavljene goveđe kože (70.7 N/mm2). Međutim, za precizniju analizu, pri ispitivanju fizičko-mehaničkih svojstava, neophodno je imati detaljnije podatke o porijeklu, parametrima štavljenja i primenjenoj završnoj obradi kože. Proces štavljenja hromom ima prednosti u pogledu kraćeg trajanja procesa štavljenja, ali i ograničenja u pogledu ekoloških zahtjeva, zbog čega biljno štavljenje ponovo dobija na značaju.
Abstract
Leather making is a very long process and consists of many different chemical and mechanical operations. The most important operation of the whole leather making process is the tanning, which is performed mainly by vegetable or chrome tanning. With this work, we wanted to establish a connection between the way leather is tanned and its physical and mechanical properties. For this purpose, certain physical and mechanical properties of bovine, sheep and goat leather, which were obtained by chrome and vegetable tanning, were examined. Tests were performed on commercially available leathers. The selected leather samples were tested for thickness, mass per unit area, apparent density, braking force and breaking elongation, while other dimensions were calculated based on previously measured values. After the measurements, the results were compared according to the type of leather and the method of tanning. The obtained results showed better physical and mechanical properties of chrome-tanned leather compared to vegetable-tanned leather, with the highest breaking strength of chrome-tanned bovine leather (70.7 N/mm2). However, for a more precise analysis, when examining the physical and mechanical properties, it is necessary to have more precise data of the origin, tanning parameters and applied leather finishing. The chrome tanning process has advantages in terms of the shorter duration of the tanning process, but chrome tanning process has significant limitations in terms of environmental requirements, which is why the vegetable tanning process is becoming more relevant again.
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