ISO 5431 pdf download

ISO 5431 pdf download

ISO 5431 pdf download Leather — Wet blue goat skins — Specification
1 Scope
This International Standard specifies requirements, methods of sampling and methods of test for wetblue leather produced from goat skins tanned without hair and with the use of basic chromium sulfateas the primary tanning agent.
2Normative references
The following documents, in whole or in part, are normatively referenced in this document and areindispensable for its application, For dated references, only the edition cited applies. For undatedreferences, the latest edition of the referenced document (including any amendments) applies.
ISO 2418, Leather – Chemical, physical and mechanical and fastness tests — Sampling location
ISO 3380, Leather — Physicaland mechanical tests — Determination ofshrinkage temperature up to 100 °
ISO 4045, Leather – Chemical tests — Determination ofpH
ISO 4684, Leather – Chemical tests — Determination ofvolatile matter
ISO 5398-1,Leather– Chemicaldetermination ofchromic oxide content– Part 1: uantification by titration
ASTM D4576, Standard test method for mold growth resistance of wet blue
3 Terms and definitions
For the purposes ofthis document, the following terms and definitions apply
preserved temporarily from putrefaction until it can be tannedNote 1 to entry: Any method of curing, including wet or dry salting or drying, is included
pigmentationcolouration produced by fungi growing on wet blue chrome leather
Note 1 to entry: The colouration produced by fungi will normally be black, white, green or yellow but can also bepink or violet.
4 Requirements
4.1 Raw material
Wet blue goat skins shall be processed from cured or fresh goat skins
After pretanning operations, the skins shall be tanned with basic chromium sulfate as the primary tanningagent. The cut cross-section shall be such that the skin is completely penetrated by the bluish colour ofthechromium sulfate when examined visually. Tanning shall be carried out at a pH of3,0 or above.
4.3 Fungicidal additives
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 effectiveand should not cause a health hazard. The types of fungicide used and their dosage should preferably be agreedbetween the purchaser and the supplier
NOTE 2Fungicides should preferably be applied in quantities appropriate to ensure storage for up to 4 monthsat the temperature and humidity prevailing during storage or transportation.
4.4 Presentation
Wet blue goat skins shall be well fleshed, and the grain side shall be free from hair, including short hairand fine hair. The size and grading shall be as agreed between the interested parties.
NOTEThe skins should preferably have a tight grain and be free from creases, drum folds and stains causedby iron salts. At least 95 % of the number of pieces in a lot should be free from stains caused by chromium saltsand the aggregate of the stained area in any one piece should not exceed 10 % of the total area of the piece.
4.5 Shrinkage temperature
The shrinkage temperature shall not be less than 95 C, when determined using the method specifiedinIS0 3380
4.6 Chemicalrequirements
Wet blue goat skins shall comply with the requirements given in Table 1.

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