BS ISO 5431:2013 pdf free
BS ISO 5431:2013 pdf free.Leather一Wet blue goat skins一Specification
After pretanning operations, the skins shall be tanned with basic chromium sulfate as the primary tanning agent. The cut cross-section shall be such that the skin is completely penetrated by the bluish colour of the chromium sulfate when examined visually. Tanning shall be carried out ata pH of 3,0 or above.
Fungicides shall be used to inhibit mould growths in the wet blue goat skins.
NOTE 1 Fungicides used to inhibit mould growth and pigmentation in wet blue goat skins should be effective and should not cause a health hazard. The types of fungicide used and their dosage should preferably be agreed between the purchaser and the supplier
NOTE 2 Fungicides should preferably be applied in quantities appropriate to ensure storage for up to 4 months at the temperature and humidity prevailing during storage or transportation.
Wet blue goat skins shall be well fleshed, and the grain side shall be free from hair, including short hair and fine hair. The size and grading shall be as agreed between the interested parties.
NOTE The skins should preferably have a tight grain and be free from creases, drum folds and stains caused by iron salts. At least 95 % of the number of pieces in a lot should be free from stains caused by chromium salts,and the aggregate of the stained area in any one piece should not exceed 10 % of the total area of the piece.
NOTE A minimum shrinkage temperature of 95 °C would normally require minimum chromic oxide content of 3,0 % relative to the dry mass, as determined by the method given by ISO 5398-1. Once the chromic oxide content has been determined in this way, it can be used to estimate how much more chromic oxide has to be added to achieve the desired level (i.e. the extent of further rechroming).BS ISO 5431 pdf download.
