1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ICS 83.060 ISBN 0-626-14408-6 SANS 11853:2003Edition 1ISO 1853:1998Edition 2SOUTH AFRICAN NATIONAL STANDARD Conducting and dissipative rubbers, vulcanize
4、d or thermoplastic Measurement of resistivity Published by Standards South Africa 1 dr lategan road groenkloof ! private bag x191 pretoria 0001 tel: 012 428 7911 fax: 012 344 1568 international code + 27 12 www.stansa.co.za Standards South Africa 2003 This national standard is the identical implemen
5、tation of ISO 1853:1998 and is adopted with the permission of the International Organization for Standardization SANS 11853:2003 Edition 1 ISO 1853:1998 Edition 2 Table of changes Change No. Date Scope National Foreword This South African standard was approved by National Committee STANSA TC 5140.17
6、, Rubber and rubber products, in accordance with procedures of Standards South Africa, in compliance with annex 3 of the WTO/TBT agreement. AReference numberISO 1853:1998(E)INTERNATIONALSTANDARDISO1853Second edition1998-03-01Conducting and dissipative rubbers,vulcanized or thermoplastic Measurement
7、of resistivityCaoutchoucs vulcaniss ou thermoplastiques conducteurs et dissipants Mesurage de la rsistivitISO 1853:1998(E) ISO 1998All rights reserved. Unless otherwise specified, no part of this publication may be reproducedor utilized in any form or by any means, electronic or mechanical, includin
8、g photocopying andmicrofilm, without permission in writing from the publisher.International Organization for StandardizationCase postale 56 CH-1211 Genve 20 SwitzerlandInternet centraliso.chX.400 c=ch; a=400net; p=iso; o=isocs; s=centralPrinted in SwitzerlandiiForewordISO (the International Organiza
9、tion for Standardization) is a worldwidefederation of national standards bodies (ISO member bodies). The work ofpreparing International Standards is normally carried out through ISOtechnical committees. Each member body interested in a subject for whicha technical committee has been established has
10、the right to be representedon that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISOcollaborates closely with the International Electrotechnical Commission(IEC) on all matters of electrotechnical standardization.Draft Inte
11、rnational Standards adopted by the technical committees arecirculated to the member bodies for voting. Publication as an InternationalStandard requires approval by at least 75 % of the member bodies castinga vote.International Standard ISO 1853 was prepared by Technical CommitteeISO/TC 45, Rubber an
12、d rubber products, Subcommittee SC 2, Physicaland degradation tests.This second edition cancels and replaces the first edition (ISO 1853:1975),which has been technically revised.Annex A of this International Standard is for information only.ISO ISO 1853:1998(E)iiiIntroductionRubber is normally regar
13、ded as a material of high electrical resistivity; consequently, it is widely used as aninsulator. However, the incorporation of various materials, in particular certain forms of carbon black, greatlyreduces the electrical resistance so that resistivities between 1013m and 0,01 m are obtainable.There
14、 are various technical and industrial purposes for which rubber with a reduced resistivity is a useful material,the most frequent application being for the dissipation of static charges. In certain circumstances, a lower limit ofresistance must be imposed on a product with this latter application, a
15、s a safety precaution to prevent its ignition orto prevent severe shock to a person in contact with it, in the event of faulty insulation or nearby electrical equipment.Products which, while conducting away static charges, are sufficiently insulating to fulfil the safety requirementsabove are termed
16、 dissipative rubbers. Products which do not fulfil the safety requirements are termed “conducting“rubbers. Since the dimensions of the product are involved it is not possible to define a suitable range of volumeresistivities for either of these classes, but only a range of resistance values between
17、defined points. Howeverconductive materials are generally considered to have a resistivity below 106m and dissipative materials to have aresistivity between 105m and 1010m.The principal hazard, apart from static electricity, in most buildings and with most electrical equipment is fromleakage current
18、s from normal voltage supply mains. To guard against these hazards, it is recommended that thelower limit of resistance for a dissipative rubber product should be 5 104ohm for 250 V mains supplies, that is amaximum current of 5 mA. The limit can be proportionally less for lower voltages.The maximum
19、resistance which will permit the dissipation of static charges depends on the rate of generation ofcharge required to produce the minimum voltage which can be regarded as a hazard in a particular application.Effect of temperature changes and strain on conducting and antistatic rubbersThe resistance
20、of these materials is very sensitive to their strain and temperature history. The relationships arecomplex and arise from the kinetic energy and structural configuration of the carbon particles in the rubber.Under normal conditions of service with varying temperature and strain history, the resistan
21、ce of a sample of agiven material can vary considerably, for example by a hundred or more times, between freshly strained materials atroom temperatures and material which has remained unstrained for a short period at 100 C.In order that valid comparisons may be made on test pieces, a conditioning tr
22、eatment is specified so that themeasurements are made on test pieces brought to a condition of zero strain.Electrode systemsCertain types of electrode, when applied to these rubbers, have a contact resistance which may be many thousandsof times greater than the intrinsic resistance of the test piece
23、. Dry contacts under light pressure or point contacts areparticularly poor.The definition of a suitable electrode system is therefore an important part of this method of test.This page is intentionally left blankINTERNATIONAL STANDARD ISO ISO 1853:1998(E)1Conducting and dissipative rubbers, vulcaniz
24、ed orthermoplastic Measurement of resistivityWARNING - Persons using this International Standard should be familiar with normal laboratory practice.This standard does not purport to address all of the safety problems, if any, associated with its use. It is theresponsibility of the user to establish
25、appropriate safety and health practices and to ensure compliancewith any national regulatory conditions.1 ScopeThis International Standard specifies the requirements for the laboratory testing of the volume resistivity of speciallyprepared test pieces of vulcanized or thermoplastic rubber compounds
26、rendered conducting or dissipative by theinclusion of carbon black or ionizable materials. Antistatic properties may also be conferred on rubber materials bythe incorporation of ionizable materials into the rubber mix. The test is suitable for materials with a resistivity of lessthan 1010m.2 Normati
27、ve referenceThe following standard contains provisions which, through reference in this text, constitute provisions of thisInternational Standard. At the time of publication, the edition indicated was valid. All standards are subject torevision, and parties to agreements based on this International
28、Standard are encouraged to investigate thepossibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintainregisters of currently valid International Standards.ISO 471:1995, Rubber -Temperatures, humidities and times for conditioning and testing3 Appara
29、tus(see figure 1 for schematic diagram of test circuit).3.1 Current source. A source of direct current which has a minimum resistance to earth of 1012ohm and which willnot cause a dissipation of power greater than 1 W within the test piece.3.2 Means of measuring the current to an accuracy of 5 %.Not
30、e 1 - Very small currents may be computed from measurement of the voltage drop across aknown resistance using the electrometer (3.5).3.3 Test piece holder and current electrodes, comprising a polystyrene strip of about 10 mm thickness where thecurrent electrodes are fixed (see figure 1). The current
31、 electrodes shall be of clean metal approximately 5 mm longand across the full width of the test piece, together with suitable clamps or grips.The distance between the current electrodes shall be 50 mm 1 mm or 100 mm 1 mm, and the resistancebetween them shall be greater than 1012.A minimum of three
32、test piece holders shall be available.ISO 1853:1998(E)ISO23.4 Potentiometric electrodes, constructed so that they exert a contacting force of approximately 0,65 N for10 mm wide test pieces or 1,3 N for 20 mm wide test pieces (see figure 2). The resistance between thepotentiometric electrodes shall b
33、e greater than 1012.3.5 Electrometer, having an input resistance greater than 1011. References for such instruments are given inannex A.3.6 Sheet of insulating material, having a resistivity greater than 1013m.3.7 Oven, capable of being controlled at a temperature of 70 C 1 C.4 Test pieceThe test pi
34、ece is a strip, 10 mm 0,5 mm or 20 mm 0,5 mm wide, of vulcanized or thermoplastic material minimum70 mm long and normally 2 mm, 4 mm or 6,3 mm thick with a tolerance of uniformity of thickness of 5 %.For comparison purposes test pieces of the same size shall be used.The test piece may be cut with a
35、knife or die but care shall be taken to minimize distorsion as this will affect theresistance values.The surfaces of the test piece shall be clean; if necessary they may be cleaned by rubbing with Fullers earth(aluminium magnesium silicate) and water, washing with distilled water and allowing to dry
36、. The surfaces shall notbe buffed or abraded.5 Number of test piecesThree test pieces of equal size shall be prepared and tested.6 ProcedureAllow the test piece to rest for not less than 16 h after vulcanization or moulding, in accordance with ISO 471.Immediately prior to the commencement of the tes
37、t, place the test piece on the test piece holder and clamp thecurrent electrodes to its ends.Without removing it from the test piece holder, heat the test piece in the oven for 2 h at a temperature of70 C 1 C and then condition for not less than 16 h at the standard laboratory temperature and humidi
38、ty inaccordance with ISO 471. Place the two potentiometric electrodes in position with a distance of 10 mm to 20 mmbetween them, ensuring that the knife edges are at right angles to the current flow and that neither is nearer than20 mm to a current electrode. Measure the distance between the potenti
39、ometric electrodes to an accuracy of 2 %.Apply the current and determine the steady potential between the potentiometric electrodes, using the electrometer,after the current has been passing for 1 min.Repeat the measuring procedure twice more on the same test piece, moving the potentiometric electro
40、des eachtime to obtain measurements over lengths of the test piece evenly distributed between the current electrodes.Similarly, test the other two test pieces.7 Expression of resultsAverage the three measurements of resistance for each test piece and calculate the resistivity, r, in ohm metres, asfo
41、llows:r =VwtlIISOISO 1853:1998(E)3whereV = measured potential in Vw = the width of the test piece in mt = the thickness of the test piece in ml = the distance between the potentiometer electrodes in mI = measured current in AReport the median value of the restivities of the three test pieces.8 Test
42、reportThe test report shall include the following information:a) a reference to this International Standard;b) sample details:1) a full description of the sample and its origin;2) compund details and cure conditions, if known;3) the dimensions of the test pieces;c) test details:1) the temperature an
43、d humidity conditions during the test;2) the voltage applied to the current electrodes;3) the current through the test piece;d) test results:1) the median value of the resistivity of the three test pieces;2) the individual average resistivity value for each test piece, if required;e) the date of tes
44、t.ISO 1853:1998(E)ISO4Dimensions in millimetresKey1 Test piece 4 Electrometer2 Current electrode 5 Potentiometric electrode3 Insulating mat Resistance at least 1012 W 6 Adjustable direct-current voltageFigure 1 Schematic diagram of test circuitKey1 Polystyrene strip2 Stainless steel3 Test specimen w
45、idth + at least 10 mm4 10 mm to 20 mm measured to 2 %Figure 2 Potentiometric electrodesISOISO 1853:1998(E)5ANNEX A(Informative)Solid state electrometerMeasurement of voltage and current in the ranges suitable for this International Standard can be performed also bymeans of a solid state electrometer
46、 having a sufficiently high input resistance.An instrument of this type is the Model 602 solid state electrometer of Keithley Instruments. Used as a voltmeter the602 Electrometer has an input resistance greater than 1014ohm and a range from 0,001 V at full scale to 10 V; asan ammeter its range is fr
47、om 10-14A at full scale to 0,3 A.This apparatus is manufactured by:Keithley Instruments28775 Aurora RoadClevelandOhio 44139USATheir European Headquarter is:Keithley Instruments GmbHLandsberger Strasse 658034 GemringGermany.An instrument measuring volume resistivity in compliance with this standard i
48、s the Elastocon EE 01 VolumeResistivity Tester. The EE 01 instrument has an integrated differential voltmeter and ammeter. The ammeter canmeasure currents down to 0,01 nA and the differential voltmeter which is integrated with the potentiometricelectrode has an input resistance of 0,1 T.This instrument is manufactured by:Elastocon ABGteborgsvgen 99S-504 60 GTEBORGSweden
