BS EN ISO 4045-2008 en 5026 Leather - Chemical tests - Determination of pH《皮革 化学试验 pH值的测定》.pdf

1、BRITISH STANDARDBS EN ISO 4045:2008Leather Chemical tests Determination of pHICS 59.140.30g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO

2、4045:2008This British Standard was published under the authority of the Standards Policy and Strategy Committee BSI 2008ISBN 978 0 580 57417 7National forewordThis British Standard is the UK implementation of EN ISO 4045:2008. It supersedes BS EN ISO 4045:1998 which is withdrawn. The UK participatio

3、n in its preparation was entrusted to Technical Committee TCI/69, Footwear, leather and coated fabrics.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are

4、responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments/corrigenda issued since publicationDate Commentson 30 May 2008EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 4045February 2008ICS 59.140.30 Supersedes EN ISO 404

5、5:1998 English VersionLeather - Chemical tests - Determination of pH (ISO 4045:2008)Cuir - Essais chimiques - Dtermination du pH (ISO4045:2008)Leder - Chemische Prfungen - Bestimmung des pH (ISO4045:2008)This European Standard was approved by CEN on 3 February 2008.CEN members are bound to comply wi

6、th the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Cen

7、tre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial

8、versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia,

9、Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national M

10、embers.Ref. No. EN ISO 4045:2008: EEN ISO 4045:2008 (E) Foreword This document (EN ISO 4045:2008) has been prepared by Technical Committee CEN/TC 289 “Leather“, the secretariat of which is held by UNI in collaboration with Technical Committee ISO/TC IULTCS “International Union of Leather Technologis

11、ts and Chemists Societies“. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by August 2008, and conflicting national standards shall be withdrawn at the latest by August 2008. Attention is drawn to t

12、he possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 4045:1998. According to the CEN/CENELEC Internal Regulations, the national st

13、andards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,

14、 Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN ISO 4045:2008ISO 4045:2008(E) IULTCS/IUC 11:2008(E) iiiForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The wo

15、rk of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governm

16、ental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The

17、main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.

18、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. ISO 4045/IUC 11 was prepared by the European Committee for Standardization (CEN) Technical Committee

19、CEN/TC 289, Leather, in collaboration with the Chemical Tests Commission of the International Union of Leather Technologists and Chemists Societies (IUC Commission, IULTCS), in accordance with the Agreement on technical co-operation between ISO and CEN (Vienna Agreement). It is based on IUC 11 origi

20、nally published in J. Soc. Leather Trades Chemists, 49, pp. 25-29, 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 t

21、hree Commissions, which are responsible for establishing international methods for sampling and the testing of leather. ISO recognizes IULTCS as an international standardizing body for the preparation of test methods for leather. This second edition cancels and replaces the first edition (ISO 4045:1

22、977), which has been technically revised. BS EN ISO 4045:2008blankISO 4045:2008(E)IULTCS/IUC 11:2008(E)1Leather Chemical tests Determination of pH 1 Scope This International Standard specifies a method for determining the pH value and the difference figure of an aqueous leather extract. It is applic

23、able to all types of leather. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) appli

24、es. ISO 2418, Leather Chemical, physical and mechanical and fastness tests Sampling location ISO 3696, Water for analytical laboratory use Specification and test methods ISO 4044, Leather Chemical tests Preparation of chemical test samples 3 Terms and definitions For the purpose of this document, th

25、e following terms and definitions apply. 3.1 difference figure difference between the pH value of a solution and that of its ten-fold dilution NOTE The difference figure is a measure of the strength of acids and bases and can never exceed a value of 1. The difference figure amounts to 0,7 to 1,0 whe

26、n a solution contains a free strong acid (or a free strong base). The ionization of weak acids and bases increases with greater dilution, and therefore the difference figure can only act as a criterion for the presence of free strong acid or base in aqueous extracts with pH values below 4 or above 1

27、0. 4 Principle Preparation of an aqueous extract from a test portion of the leather and measurement of the pH of the extract, using a pH meter. In cases where the pH value obtained is below 4,00 or above 10,00, the pH value of a ten-fold dilution of the aqueous extract is also determined. 5 Reagents

28、 5.1 Water, Grade 3 in accordance with ISO 3696. The water shall be kept in a freshly boiled-out container of resistant glass of low alkali content. 5.2 Buffer solution, for calibrating the electrode system. BS EN ISO 4045:2008ISO 4045:2008(E) IULTCS/IUC 11:2008(E) 2 It is preferable to purchase a c

29、ommercially available standard buffer solution for measurement as recommended by the pH meter manufacturer. The length of time for which buffer solutions will keep depends on their composition and the method of use. Control of the accuracy of the buffer solution is therefore indispensable. Used buff

30、er solution shall be discarded. 6 Apparatus 6.1 Suitable shaker, adjusted to a frequency of (50 10) min1. 6.2 pH meter, with glass electrode, with a measuring range from 0 to 14 pH units, graduated in 0,05 pH units. The electrode system shall be calibrated prior to each series of measurements agains

31、t the buffer solution (5.2). Aqueous extracts of heavily fat-liquored leather may in time make the electrode membrane dirty. In such cases, the membrane shall be lightly rubbed with a piece of cotton wool dipped in acetone or the electrode should be suspended in a 1:1 water:acetone mixture. After cl

32、eaning, the membrane should again be thoroughly soaked in water. 6.3 Analytical balance, capable of weighing to an accuracy of 0,1 mg. 6.4 Wide mouthed flask, with leak-proof stopper, capacity 250 ml. 6.5 Measuring cylinder, capacity 100 ml, graduated in 1 ml divisions. 6.6 Volumetric flask, capacit

33、y 100 ml. 6.7 Pipette, capacity 10 ml. 7 Sampling and preparation of the samples If possible, sample in accordance with ISO 2418. If sampling in accordance with ISO 2418 is not possible, then details about sampling shall be given in the test report. Grind the leather in accordance with ISO 4044. Two

34、 separate samples shall be analysed. 8 Procedure 8.1 Preparation of the extract Weigh (5 0,1) g of the test sample into the wide mouthed flask (6.4) and add (100 1) ml of water (5.1) at (20 2) C. Shake well by hand for about 30 s so that the test portion is uniformly wet. Shake mechanically in the s

35、haker (6.1) for between 6 h and 6,5 h. Allow the extract to settle before decanting. If difficulty is experienced in decanting the extract from the slurry, it may be strained through a clean, dry, non-absorbent mesh (for example, nylon cloth or a coarse sintered glass filter), or centrifuged. 8.2 De

36、termination of the pH value Standardize the pH meter with two buffer solutions; one below the expected value and one above the expected value. Both these buffer readings shall be within 0,02 pH unit of the correct reading when the meter is standardised. Ensure that the extract (8.1) is at (20 2) C.

37、Immediately after stirring the extract solution, determine the pH value with the pH meter (6.2), to the nearest 0,05 pH unit, as soon as a steady reading has been reached. The reading shall be taken within 30 s to 60 s after rinsing the electrodes in the extract. BS EN ISO 4045:2008ISO 4045:2008(E)

38、IULTCS/IUC 11:2008(E) 38.3 Determination of the difference figure If the pH value is below 4 or over 10, the difference figure shall be determined. For this determination, transfer, using the pipette (6.7), 10 ml of the extract into the volumetric flask (6.6) and make up to the mark with water. Rins

39、e the electrodes with approximately 20 ml of the diluted solution and then measure the pH value as in 8.2. 8.4 Calculation of the difference figure The difference figure is calculated by subtracting the pH value obtained in 8.3 from that obtained in 8.2. The result is quoted to the nearest 0,05 pH u

40、nit. 9 Test report The test report shall include the following: a) reference to this International Standard (ISO 4045); b) details of any deviations from the prescribed test conditions; c) reference to any instability of the pH reading of the extract which prevents an unequivocal statement of the pH

41、 value or difference figure; d) a statement of the mean value of the individual determinations of pH value and, if this is below 4 or above 10, the difference figure. The figures shall be given to the nearest 0,05 pH unit. BS EN ISO 4045:2008BS EN ISO 4045:2008BSI389 Chiswick High RoadLondonW4 4ALBS

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