ISO 4044:2017 pdf download – 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
For the purposes of this document, the terms and definitions given in EN 15987 apply.
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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.
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.