ISO 5433:2022

Leather - Bovine wet blue - Specification

This document specifies requirements, sampling methods and testing methods for wet blue leather produced from bovine hides and parts of bovine hides tanned without hair and with the use of basic chromium sulfate as the primary tanning agent.

Cuir — Peaux de bovins à l'état "bleu humide" — Spécifications

General Information

• Status: Published
• Publication Date: 17-Nov-2022
• ICS: 59.140.30 - Leather and furs
• Technical Committee: ISO/TC 120/SC 2 - Tanned leather
• Drafting Committee: ISO/TC 120/SC 2 - Tanned leather
• Current Stage: 6060 - International Standard published
• Start Date: 18-Nov-2022
• Due Date: 09-Aug-2022
• Completion Date: 18-Nov-2022

Relations

• Revises: ISO 5433:2013 - Leather - Bovine wet blue - Specification
• Effective Date: 17-Jul-2021

Overview

ISO 5433:2022 - Leather - Bovine wet blue - Specification defines requirements, sampling and test methods for bovine wet blue leather tanned primarily with basic chromium sulfate. This third edition (2022) replaces ISO 5433:2013 and provides standardized criteria for raw material, tanning, presentation, chemical limits, shrinkage temperature, fungicide use, sampling, testing, packaging and marking of wet blue bovine hides and parts.

Key topics and technical requirements

• Tanning: Must use basic chromium sulfate as the primary tanning agent; visual inspection shall show complete penetration by the bluish chromium color. Tanning carried out at pH ≥ 3.0.
• Shrinkage temperature: Measured per ISO 3380. Minimums: ≥ 85 °C for low chrome tannage and ≥ 100 °C for full chrome tannage. Chromic oxide content guidance links to these requirements.
• Chemical requirements (Table 2):
  • Volatile matter: > 50% of dry mass (or as agreed)
  • Matter soluble in dichloromethane: < 2% of dry mass (or as agreed)
  • pH of water extract: ≥ 3.2
• Fungicidal additives: Fungicides should inhibit mould and pigmentation, be non-hazardous, and doses agreed between purchaser and supplier; recommended protection for storage up to 4 months under prevailing conditions.
• Presentation and appearance: Grain side free from hair; preferably tight grain with no creases or iron-stain; at least 95% of pieces in a lot should be free from chromium salt stains, with any stained area per piece not exceeding 10% of total area.
• Sampling & dispute resolution: Routine sampling agreed between parties; dispute sampling quantities specified (e.g., up to 100 skins → 3 samples; 701+ → 7 samples) and locations per ISO 2418.
• Packaging and marking: Packages must preserve original wet condition; labels to include material type, manufacturer, tanning month/year, number of skins and purchaser-required details.

Applications

ISO 5433:2022 is used for:

• Quality control and acceptance criteria in leather manufacturing and tannery operations.
• Procurement specifications for buyers and traders of bovine wet blue leather.
• Laboratory testing and certification for compliance with industry standards.
• Contractual dispute resolution where standardized sampling and testing are required.
• Logistics and storage planning to ensure product stability and antifungal protection.

Who should use this standard

• Tannery managers and production engineers
• Quality assurance and laboratory personnel (physical/chemical testing)
• Leather traders, buyers, importers/exporters
• Standards and compliance officers in the leather value chain

Related standards

Normative references used by ISO 5433:2022 include: ISO 2418, ISO 3380, ISO 4044, ISO 4045, ISO 4048, ISO 4684, ASTM D4576 and ISO 5398-1 for chromic oxide determination. These are essential for implementing the specified test and sampling methods.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 5433
Third edition
2022-11
Leather — Bovine wet blue —
Specification
Cuir — Peaux de bovins à l'état "bleu humide" — Spécifications
Reference number
© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
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Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Requirements . 2
4.1 Raw material . 2
4.2 Form and trimming . 2
4.3 Tanning . 2
4.4 Fungicidal additives . 3
4.5 Presentation . . 3
4.6 Shrinkage temperature . 3
4.7 Chemical requirements . . 3
5 Sampling . 4
5.1 Sampling for routine testing . 4
5.2 Sampling in case of dispute . 4
5.3 Preparation of samples . 4
6 Test methods . 4
6.1 Visual tests . 4
6.2 Shrinkage temperature . 4
6.3 Volatile matter . 4
6.4 pH of the water extract . 4
6.5 Effectiveness of the fungicide . 4
6.6 Determination of matter soluble in dichloromethane . 4
7 Packaging and marking . 5
7.1 Packaging . 5
7.2 Marking . 5
Bibliography . 6
iii
Foreword
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This document was prepared by Technical Committee ISO/TC 120, Leather, Subcommittee SC 2, Tanned
leather.
This third edition cancels and replaces the second edition (ISO 5433:2013), which has been technically
revised.
The main changes are as follows:
— sample preparation method has been added in 6.3 and 6.4;
— determination of matter soluble in dichloromethane has been added as 6.6 in the Test methods;
— type of material has been mentioned in 7.2 (a);
...