1、 STDOBSI BS EN IS0 3915-ENGL 1999 II lib24bb9 0793798 O19 iiai BRITISH STANDARD Plastics - Measurement of resistivity of conductive plastics The European Standard EN IS0 3915 1999 has the status of a British Standard ICs 29.050; 83.080.01 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPY
2、RIGH LAW BS EN IS0 3915:1999 STD-BSI BS EN IS0 3915-ENGL 1999 111 1b2Libb9 O793799 T55 been prepared under the direction of the Sector Amd. No. Date Committee for Materiais and Chemicals, was published under the authority of the Standards Committee and comes into effect on 15 September 1999 0 BSI 09
3、-1999 ISBN O 580 32880 6 BS EN IS0 3916:1999 Comments National foreword This British Standard is the English ianguage version of EN IS0 39151981. It is identical with IS0 39151981. The UK participation in its preparation was entrusted to Technical Committee PRW1, Testing of plastics, which has the r
4、esponsibility to: - aid enquirers to undentand the te them in the UK. - monitor related international and European developments and promulgate A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references Attention is dram to the fact that CEN an
5、d CENELEC Standards normally include an annex which lists nomiative references to international publications with their corresponding European publications. The British Standards which implement hese international or European publications may be found in the BSI Standards Catalogue under the section
6、 entitled “International Standards Correspondence Index”, or by wing the “F” facility of the BSI Standards Eleclxonic Catalogue. A British Standard does not purport to include all the necessary provisions of a conixact. Users of British Standards are responsible for their correct application. Compli
7、ance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN IS0 title page, the EN IS0 foreword page, the IS0 title page, the IS0 foreword page, pages 1 to 4, an inside back cover and a
8、back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. STD-BSI BS EN IS0 39L5-ENGL 1999 m Lb24669 0793800 5T7 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN IS0 3915 June 1999 ICs 83.080.00 English version Plastics - Measurement of resistiv
9、ity of conductive plastics (IS0 3915:1981) Plastiques - Mesurage de la r$sistivit des plastiques conducteurs (Is0 3915:1981) Kunststoff e - Messung des spedfischen elektrischen Widerstandes von leifhigen Kunststoffen (IS0 39151981) This European Standard was approved by CEN on 6 May 1999. CEN member
10、s are bound to comply with the CENiCENELEC Intemal Regulations which stipulate the conditions for giving this European Standard the status of a national srartdard without any aiteraiion. Up-to-date lists and blbliographicai references concerning such national standards may be obtained on application
11、 to the Central Secretariat or to any CEN member. This European Standard exists in three officiel versions (English, French, Gem). A vsrsion in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same s
12、tatus as the offidal versions. CEN members are the nationai standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany. Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMEE FOR STANDARD
13、EATION COMITE EUROPEEN DE NORMALISATION EUROPISCHES KOMITEE FOR NORMUNG Central Secretariat: rue de Stassart, 36 8-1050 BNSSIS Q 1999 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. NO. EN Is0 3915:1999 E Foreword The text of the Internat
14、ional Standard from Technical Committee ISOiTC 61 “Plastics“ of the International Organization for Standardization (ISO) has been taken over as an European Standard by Technical Committee CEN/TC 249 “Plastics“, the secretariat of which is held by IBN. This European Standard shall be given the status
15、 of a national standard, either by publication of an identical text or by endorsement, at the latest by December 1999, and conflicting national standards shall be withdrawn at the latest by December 1999. According to the CENKENELEC Internal Regulations, the national standards organizations of the f
16、ollowing countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of the Int
17、ernational Standard IS0 39151981 has been approved by CEN as a European Standard without any modification. STD BSI BS EN IS0 39L5-ENGL Lbt4bb9 0793802 37T EN IS0 3916:1999 International Standard 3915 INTERNATIONAL DRGANIZATIOEI FOR STANDARD1 LATlONWEXAYHAPOHAn OPrAHH3AUHR Il0 CTAHA.4PTH3AUHH.OAWNlSA
18、llON INTERNATIONALE DE NORMALISATION Plastics - Measurement of resistivity of conductive plastics Fyestiques - Mesurage de la rsistivit des plastiques conducteurs First edition - 1981-11-01 UDC 67 however, a wider strip may be used, with correspondingly wider electrodes. There is a danger in using a
19、 wide strip, if the strip is slightly twisted and at the same time somewhat non-uniform in its resistivity. It is then possible to obtain erroneous results; the potential electrode nearer to the positive current electrode may even be found to be negative with respect to the other potential electrode
20、. Effect of temperature changes and strain on conductive plastics As mentioned above, the resistance of these materials is sensi- tive to their temperature-history and strain-history. The rela- tionships are complex and arise from the kinetic energy and structural configuration of the carbon particl
21、es in the polymer. The resistivity may be increased by the effects of strain pro- duced by (or subsequent to) removal from the mould, and a treatment is described for reducing specimens to a constant strain and temperature condition before measurements are car- ried out on them. Specimens are also c
22、ut in two perpendicular directions to assess anisotropy. Electrode systems (see 3.3) Certain types of electrode, when applied to these polymers, have a contact resistance which may be many thousand times greater than the intrinsic resistance of the specimen. Dry con- tacts under light pressure or po
23、int contacts give very high resistances. However, the present test method eliminates the ffects of contact resistances unless these are excessively high. I In such a case, no result, rather than a wrong one, is generally obtained. i 1 Scope and field of application This International Standard specif
24、ies the requirements for the laboratory testing of the resistivity of specially prapared specimens of plastics rendered conductive by the inclusion of carbon black. The test is suitable for materials of resistivity less than 10s Qacm (1W Cbmi. The result is not strictly a volume resistivity, because
25、 of surface conduction, but the effects of the latter are generally negligible. The principie of the four-terminal method of test is mandatory and the recommended specimen size and electrode design must be adhered to for reference purposes, but it may sometimes be necessary to test a wider strip wit
26、h electrodes of a different construction. 2 Principle A stable d.c. current of magnitude (fi is passed between elec- trodes at the two ends of a strip of the material under test. The voltage drop (AU) between two potential electrodes is measured with an electrometer. The resistance of the portion of
27、 the strip between the potential electrodes is given by R = AUII, and is independent of contact resistances. Thus the resistivity may be calculated. 3 circuit1 Apparatus (see figure 1 for schematic diagram of test 3.1 Current source : a source of direct current which has a minimum resistance to eart
28、h of 1012 Q (effected by placing it on a highly insulating sheet), and which will not cause a dissipa- tion of power greater than 0,l W in the specimen. 3.2. measuring the current to an accuracy of i 5 %. Milliammeter or microemmeter, as appropriate, for NOTE - Small currents may be computed from me
29、asurement of the voltage drop across a known resistance in series with the specimen, using the electrometer (3.4 3.3 Electrodes 3.3.1 Current electrodes, of clean metal, together with either suitable clamps or grips approximately 5 mm long and extending across the full width of the specimen, or cond
30、uctive paint to cover the same area. 1 STDaBSI BS EN IS0 391i5-ENGL 1999 m Lb24bb9 0793805 O89 6 EN IS0 3915:1999 3.3.2 Potentiometric electrode system (see figure 2, for example), having a mass of approximately 60 g so that it exerts a force of approximately 0.6 N on the specimen. The contacts shal
31、l normally be 10 f 0,2 mrn apart. For special purposes, the contacts may be further apart (up to 70 mm), but the separa- tion shall be less than the specimen length by at least 60 mm. The distance between the contacts shall be known to an accu- racy of * 2 %. The insulation resistance between the co
32、ntacts shall be at least 1012 n. 3.4 Electrometer, having an input resistance greater than 1011 S and measuring to an accuracy of f 5 %. 3.5 Sheet of highly insulating material, having a volume resistivity greater than 1015 Qwn. 3.6 Oven. capable of being maintained at a temperature ofm * 2oc. 4 Spe
33、cimen The specimen shall be a strip 10 rnm wide and 70 to 150 mm long and shall normally be 3 to 4 mm thick with a tolerance on uniformity of thickness of $r 5 %. Thicker or thinner speci- mens may be cut from sheets or products. Care shall be taken to avoid bending or stretching the sheets or speci
34、mens, espe- cially when they are thinner than standard. The specimen may be cut with a knife or razor blade, but care must be taken to minimize distortion as this will affect the resis- tance values. The surfaces of the specimen shall be clean; if necessary, they may be cleaned by rubbing with fulle
35、rs earth (hydrated magnesium-aluminium silicate) and water, rinsing with distilled water and allowing to dry.1) The surfaces shall neither be buffed nor abraded, nor shall they be cleaned with organic materials that attack or swell the materiat. 5 Number of specimens From each of two perpendicular d
36、irections, three specimens of equal size shall be prepared and tested. The two directions should, where possible, be chosen to be along and across any direction of flow during processing. 6 Procedure 6.1 After preparation, allow the specimen to remain at room temperature and ambient humidity conditi
37、ons for at least 16 h. 6.2 Prior to the commencement of the test, connect the cur- rent electrodes (3.3.11 to the ends of the specimen, either by using the clamps or grips, or by covering the same area with conductive paint. 6.3 The required conditioning of the specimen should be described in the ma
38、terial specification. If this is not the case, the following procedure will probably be useful in most cases : Immediately after applying the current electrodes, place the specimen on the sheet of highly insulating material (3.5) and heat in the oven (3.6) for 2 h at a temperature of 70 f 2 OC to re
39、move strains and irregularities caused by previous treatment. Cool for at least 1 h and test at 23 i 2 OC and 50 f 5 % relative humidity without disturbing the specimen. The specimen shall always be tested on the sheet of insulating material. With some materials, distortion may occur at 70 OC and he
40、ating for 5 h at 60 * 2 OC may then be preferable. 6.4 Piace the potentiometric electrode system (3.3.2) on the specimen, ensuring that the knife-edge contacts are at right angles to the direction of current flow and that neither potentiometric electrode is within 20 mm of a current elec- trode. App
41、ly the current and measure the voltage drop be- tween the potentiometric electrodes using the electro- meter (3.41. Repeat the measuring procedure mice more on the same mi- men, moving the potentiometric electrodes each time to obtain measurements over lengths of specimen evenly distributed between
42、the current electrodes. 6.5 Test the other five specimens similarly. 7 Expression of results 7.1 Calculate the resistance R, in ohms, corresponding to each position of the potentiometric electrodes, using the for- mula AU I R =- where AV is the voltage drop, in volts, between the potentio- metric el
43、ectrodes; I is the current, in amperes, through the specimen. 7.2 The resistivity e, expressed in ohm centimetres, is given by the formula RxA d =- where R is the resistance, in ohms, calculated in accordance with 7.1; A is the cross-sectional area, in square centimetres, of a specimen perpendicular
44、 to the current flow (see figure 3); 1) If a particular drying method is necessary, it should be stated in the material specification. 2 STDmBSI BS EN IS0 3915-ENGL 1999 W lb2Libh9 079380b TI5 m EN IS0 3916:1999 d is the distance, in centimetres, between the potentio- metric electrodes. For each dir
45、ection of current flow, determine the median of the nine resistivity values thus calculated. 8 Test report The test report shall include the following particulars : a) reference to this International Standard; bl complete identification of the sample, induding processing details if relevant; Spscimn
46、 c) dimensions of the test specimen; d) conditioning, if different from that described in 6.3, or if the 60 OC conditioning is used; e) the distance between the potentiometric electrodes; f) the average value of voltage drop measured; g) the individual resistivity values and the medians of the resul
47、ts in the two directions of test; h) any other details that may have had an effect on the test results. L Current electrode Electrometer L Potentiometric electrode The insulation resistance to earth of all components within this rectangle shall be geater than 1012 SI. Figure 1 - Schematic diagram of
48、 test circuit 3 Sodon A-A E E VI O r I. s Brart, nickel or stainless Steel Radius 0.6 mm d 1 I 20 mm 4 c Figure 2 - Potentiometric electrodes r cumnt *lectrodes Figure 3 - Test specimen 4 BS EN IS0 3915:1999 BSI 389 Chiswick High Road London w4 4AL BSI - British Standards Institution BSI is the inde
49、pendent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions British Standards are updated by amendment or revision. Users of British Standards should make sure that they possess the Wst amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical c
