INTERNATIONAL ISO

STANDARD 4044
IULTCS/IUC 3

Third edition
2017-01

Leather — Chemical tests —

Preparation of chemical test samples
Cuir — Essais chimiques - Préparation des échantillons pour essais
chimiques

Reference numbers
ISO 4044:2017(E)
IULTCS/IUC 3:2017(E)

© ISO 2017
ISO 4044:2017(E)
IULTCS/IUC 3:2017(E)

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 ISO 4044:2017(E)
IULTCS/IUC 3:2017(E)

Contents Page

Foreword ..........................................................................................................................................................................iv
1 Scope .......................................................................................................................................................1
2 Normative references ..........................................................................................................................1
3 Terms and definitions .........................................................................................................................1
4 Principle .................................................................................................................................................1
5 Apparatus .....................................................................................................................................................1
6 Preparation of test sample .................................................................................................................2
6.1 Sample preparation ......................................................................................................................... 2
6.2 Grinding ...................................................................................................................................... 2
6.3 Cutting ............................................................................................................................................... 2
6.4 Choice of sample preparation method ...................................................................................... 2
7 Storage of test sample ..........................................................................................................................2
Annex A (informative) Commercial sources for apparatus ...........................................................................3
Bibliography .............................................................................................................................................................4

© ISO 2017 – All rights reserved iii

ISO 4044:2017(E)
IULTCS/IUC 3:2017(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see w w w.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see w w w.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html

ISO 4044 was prepared by the Chemical Test Commission of the International Union of Leather
Technologists and Chemists Societies (IUC Commission, IULTCS) in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 289, Leather, the secretariat of
which is held by UNI, in accordance with the Agreement on Technical cooperation between ISO and CEN
(Vienna Agreement).
ISO 4044 was prepared by the International Union of Leather
Technologists and Chemists Societies (IUC Commission, IULTCS) in collaboration with the European
Committee for Standardization (CEN).aeI/A
cagtarloege/m
staenndatrodsn/stiset/cbh82n7ic5fa6l5c-8o8offp-4edr1a5t-iob1ne9between ISO and CEN
(Vienna Agreement).
It is based on IUC 3 originally published in J. Soc. Leather Trades Chemists, 49, pp. 8-10, 1965, and
declared an official method of the IULTCS in 1965.
IULTCS, originally formed in 1897, is a world-wide organization of professional leather societies to
further the advancement of leather science and technology. IULTCS has three Commissions, which
are responsible for establishing international methods for the sampling and testing of leather. ISO
recognizes IULTCS as an international standardizing body for the preparation of test methods for
leather.
This third edition cancels and replaces the second edition (ISO 4044:2008), which has been technically
revised.
Experience has shown it can be difficult to find a suitable grinding (or cutter) mills for preparing ground
leather samples without considerable heating of the milling chamber or blocking of the sieve. Those
mills commercially available require reasonably large leather samples to prepare a representative
ground sample. But in many cases where consumer items are being tested, only small pieces of leather
are available for testing. For this reason, Subclause 6.3 has been added to allow preparation of test
samples by cutting the leather into small pieces with a sharp blade. An informative Annex A has been
added to give help with locating a suitable grinding mill.

4 © ISO 2017 – All rights reserved

 ISO 4044:2017(E)
INTERNATIONAL STANDARD
IULTCS/IUC 3:2017(E)

Leather — Chemical tests — Preparation of chemical test

samples

1 Scope
This document specifies how to prepare a test sample of leather for chemical analysis. The test sample
can be either ground or cut into small pieces. Unless specified in this document, the method to be used
depends on the size of leather sample available for testing.

2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 2419, Leather — Physical and mechanical tests — Sample preparation and conditioning

3 Terms and definitions

4
For the purposes of this document the terms and definitions given in EN15987 apply

ISO and IEC maintain terminological databases use in standardization at the following addresses:

— ISO Online browsing platform: available at http://www.iso.org/obp

— IEC Electropedia: available at http://www.electropedia.org/

4 Principle
The leather sample shall be prepared by either:
— grinding in a mill to form “ground leather”, see 5.1 and 6.2, or
— cutting into small pieces, see 5.2 and 6.3.
Which sample preparation shall be used depends on the size of the leather sample available or what
preparation method is defined in the test method procedure.

5 Apparatus

5.1 Grinding mill, having a blade rotational frequency of 300 r/min to 1 000 r/min and a perforated
sieving plate with (4,0 ± 0,5) mm diameter perforations. The mill blades shall be sharp. To avoid samples
heating up during grinding the preferred blade rotation should be towards the lower end of the rotational
frequency range. Temperature shall not be higher than 40° C. Information about a suitable grinding mill
is given in Annex A.

5.2 Suitable tool with a sharp blade for cutting leather samples into small pieces of 3 mm to 5 mm
side length.

© ISO 2017 – All rights reserved 1

ISO 4044:2017(E)
IULTCS/IUC 3:2017(E)

6 Preparation of test sample

6.1 Sample preparation

Test pieces that are wet (i.e. in excess of approximately 30 % moisture) should be pre-dried at a
temperature not exceeding 40 °C. The drying temperature should be selected with consideration of the
influence of elevated temperature on the nature of the analyte.
If the samples are dried at elevated temperature, they shall be conditioned according to ISO 2419.

6.2 Grinding
This method of preparation shall be used when a sufficiently large piece of leather is available for
grinding in a mill (5.1) to give a representative ground leather sample. As a guideline for the purpose of
this document, the leather sample should be at least 200 mm × 200 mm or more than 10 g.
Before grinding, the samples of leather should be reduced to small pieces of suitable dimensions
depending on the design of the cutter mill feed system.
It shall be ensured that the grinding mill and sample collecting device are clean. Water should not be
used for cleaning.
If sufficient sample is available, then a few small pieces of test leather should be ground and discarded,
with the apparatus being cleaned again before proceeding with grinding the main test sample.

6.3 Cutting
This method of preparation is used when only a small piece of leather is available. Typically this sample
will be a part of a consumer item, for example a leather panel or piece from a leather product. For some
leather test procedures it may be preferable to use test samples cut into pieces
The leather test samples are cut into small pieces using a suitable device with a sharp blade (5.2). The
pieces shall be of 3 mm to 5 mm side length.

6.4 Choice of sample preparation method

When the method for sample preparation is defined in a specific test method then the procedure
specified shall be used.
If no method of preparation is defined, then procedures specified in 6.2 and 6.3 are selected according to
the size of the leather sample available. The method of preparation shall be reported in the test report.

7 Storage of test sample

After grinding or cutting, the leather test sample shall be mixed thoroughly and placed in a clean, dry,
airtight container. The container shall be kept away from localized sources of heat.

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 ISO 4044:2017(E)
IULTCS/IUC 3:2017(E)

Annex A
(informative)

Commercial sources for apparatus

A.1 General
Examples of a suitable apparatus available commercially are given below. This information is given
for the convenience of users of this document and does not constitute an endorsement by ISO of these
products.

A.2 Grinding apparatus

A suitable grinding mill (also called cutting mills) is one that efficiently cuts and grinds the leather
without blocking and leaving only a small amount of unground leather. The milling chamber should
be easy to open to allow cleaning between samples. During the grinding process, the speed of the
cutter blade should not be excessive, so that the temperature in the milling chamber does not heat-
up noticeably. To achieve these requirements, grinding mills with a small, easily accessible milling
chamber and a slower blade rotation are preferred. The ground sample should readily pass through a
perforated sieving plate with (4,0 ± 0,5) mm diameter perforations

To ensure there is no contamination fromheavy metals such a as chromium, the metal parts of the
grinding mill are made of chromium-free steel and the cutting blade is made with hardened tungsten
carbide.
An example of a suitable machine is the universal curtting mill of type Pulverisette 19 with a
rotational frequency of 300 min−1 to 360 min−1. This cutting mill is a combination of type Pulverisette
19 (original
rotational frequency of 2 800 min−1) and a slower motor system of type Pulverisette 25. The equipment
with this combination is manufactured by Fritsch GmbH, Industriestrasse 8, D-55743 Idar-Oberstein,
Germany. Website: w w w.fritsch-milling.com.
Any other grinding mill equipment may be used, provided it gives a ground leather sample as described
above and the grinding chamber does not heat-up noticeably during grinding. Technical information on
the grinding of leather is given in Reference [2].

© ISO 2017 – All rights reserved 3

ISO 4044:2017(E)
IULTCS/IUC 3:2017(E)

Bibliography

[1] EN 15987, Leather — Terminology — Key definitions for the leather trade
[2] Morgenstern U., Schulz H., Hopfe W. Probenvorbereitung bei Leder (Sample
preparation for leather), Labo (4/2014): 38 – 41

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