Tso NTERNATIONAL STANDARD 3073 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKIyHAPOIHAN OPrAHW3ALNS IIO CTAHIAPTH3ALIHN.ORGANISATION INTERNATIONALE DE NORMALISATION Wool -- Determination of acid content Laine -- Determination de I'acidité First edition -- 1975-12-15 iO3073-1975 (E) Ref. No. 1S0 3073-1975 (E) UDC 677.31 : 545.2 : 54-32 Descriptors : wool, wool fibres, chemical analysis, measurement, acidity. Copyright International Oorganization for Standardization Price based on 2 pages Not for Resale FOREWORD ISO (the International Organization for Standardization) is a worldwide federation of national standards institutes (IsO Member Bodies). The work of developing International Standards is carried out through ISO Technical Committees. Every Member Body interested in a subject for which a Technical Committee has been set up has the right to be represented on that Committee. International organizations, governmental and non-governmental, in liaison with IsO, also take part in the work. Draft International Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International Standards by the ISO Council. International Standard ISO 3073 was drawn up by Technical Committee ISO/TC 38, Textiles, and circulated to the Member Bodies in October 1974. It has been approved by the Member Bodies of the following countries : Hungary Australia South Africa, Rep. of Belgium India Spain Bulgaria Sweden Iran Canada Ireland Turkey Israel United Kingdom Chile ueder U.S.A. Czechoslovakia Denmark U.S.S.R. Netherlands Finland New Zealand Yugoslavia Poland France Germany Romania No Member Body expressed disapproval of the document. This International Standard is based on Test Method IWTO-3-65, drawn up by the International Wool Textile Organization (IWTO). @ International Organization for Standardization,1975 Printed in Switzerland Not for Resale ISO 3073-1975 (E) INTERNATIONAL STANDARD Wool - Determination of acid content 1 SCOPEAND FIELD OF APPLICATION 5.2 Conical flasks, 250 ml capacity. This International Standard specifies a method for 5.3 Pipettes, 50 and 100 ml capacity. determining the acid content of a wool sample, expressed as a percentage by mass. 5.4 Burette, 25 ml capacity. This method is applicable to undyed wool in any form, for example loose fibre, sliver, yarn or fabric. It is also 5.5 Stoppered weighing bottle. applicable to dyed wool when the amount of dye extracted during the test does not interfere with the determination 5.6 Analytical balance, accurate to 0,000 5 g. of the end-point of the titration. 5.7 Desiccator. 2 PRINCIPLE 5.8 Ventilated oven for drying samples at 105 ± 3 °c. Immersion of a known amount of the wool in a dilute solution of pyridine which extracts the acid from the wool. 5.9 Mechanical shaker (optional). Determination of the amount of acid extracted, by titration with standard sodium hydroxide solution. 5.10 Glass beakers, 250 ml capacity. 3 REFERENCE 5.11 Glass wool. IsO 1130, Textile fibres - Some methods of sampling for 6 SAMPLING testing. Take a sample representative of the bulk and of mass not 4 REAGENTS less than 10 g1). It is assumed that the sample is commercially free from oil and fatty matter. 4.1 Pyridine, 5 g/l solution. Useful information on sampling is given in ISO 1130. Dissolve 5 g of pyridine (analytical grade) in 1 1 of distilled water. 7 PROCEDURE 7.1 Take at least two test specimens representative of the 4.2 Sodium hydroxide, 0,1 N solution. sample, each of mass 2 ± 0,001 g, and one specimen of mass Standardize this solution by titration with standard 1 ± 0,001 g. potassium hydrogen phthalate solution. 7.2 Place the 1 g test specimen in a weighing bottle (5.5) 4.3 Phenolphthalein, 5 g/l ethanolic solution. and dry in the ventilated oven (5.8) at 105 ± 3 °c. Stopper the bottle, cool in the desiccator (5.7) and determine the Dissolve 0,5 g of phenolphthalein in 95 % (V/V) ethanol mass of the bottie and contents. Contin