| Titre : |
Neutralising chemicals |
| Type de document : |
texte imprimé |
| Auteurs : |
Karl Flowers, Auteur |
| Année de publication : |
2019 |
| Article en page(s) : |
p. 108-111 |
| Langues : |
Anglais (eng) |
| Catégories : |
Neutralisants (chimie)
pH
Post-tannage
Wet-blue (tannage)Peau tannée au chrome (le chrome donne une couleur bleue)
|
| Index. décimale : |
675 Technologie du cuir et de la fourrure |
| Résumé : |
In the post tanning operations of a tannery, a heavy dependence is laid on the pH values of the wet end stage. It has been known rince the acceptance of chromium as a viable tanning method that the post tanning operations play a large role in helping to decide the final properties of the resulting leather.
For a chemist trained outside of the tanning industry, the term neutralisation means to take the bath pH value from either an alkaline or an acidic value to the neutral point (pH 7). This is not what tanners mean when they refer to neutralisation (the pH is very seldom pH 7). Others will refer to neutralisation as to the neutralisation of electrical charge in the leather collagen. Again, the state of electrical neutralisation is very seldom complete. Tanners seldom get to the iso-electric point, IEP (see Table 1), but the act of neutralising is certainly something that does take place.
The obvious way forward is not to refer to the operation in chromium tanned leather as neutralisation, but rather as neutralising. Another version of neutralising is taking the leather, electrically, to the IEP (neutralisation) and beyond, see Figure 1. This is often referred to as anionisation and is a common tactic in the preparation of water-resistant leathers. Another common anionisation or true neutralisation is seen in the manufacture of wet-white leathers or in vegetable tanned leathers. |
| Note de contenu : |
- Objectives of neutralising
- Can we leave neutralising out ?
- Types of chemicals
- Table 1 : The theoretical iso-electric point pH values (taken from Sharphouse, 1989)
- Fig. 1 : Zeta potential showing the charge according to pH value
- Fig. 2 : Chemical groups of neutralising syntans and agents
- Fig. 3 : Buffering solution pH profile |
| En ligne : |
https://drive.google.com/file/d/12ig4wDHBKAasa3LrNUY5jbnVfd6NFnYf/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33627 |
in INTERNATIONAL LEATHER MAKER (ILM) > N° 37 (09-10/2019) . - p. 108-111
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Neutralising chemicals in INTERNATIONAL LEATHER MAKER (ILM), N° 37 (09-10/2019)
