BS ISO 1853:2011 pdf download
BS ISO 1853:2011 pdf download.Conducting and dissipativer ubbers, vulcanized or thermoplastic— Measurement of resistivity.
4.1.2 Mould, suitable for use with brass electrodes
4.1.3 Sheets of insulating material, with a volume resistivity greater than 1013 Om and a surface resistivity greater than 1014 ci
4.1.4 Oven, capable of being controlled at (70 ± 2) C.
4.1.5 ResIstance-measuring Instrument Any suitable resistance-measuring instrument which does not diss*pate more than 025W in the test piece.
4.2 Test piece
Each test piece shall be a rectangular stnp of rubber bonded during moulding to brass electrodes, with the dimensions given in Table 1 and shown in Figure 3.
Either clean the brass electrodes In dilute nitric acid, wash with stiIed water and allow to dry, or clean them with emery cloth. If brass-plated electrodes are used, ensure that the cleaning treatment does not remove the plating. Do not apply cements or rubber solulions to the brass or rubber, as these could affect the electrical resistance.
When moulding the test pieces, ensure that the state of cure is similar to that of the product for which the compound is to be used
Ensure also that the rubber blanks placed in the mould are of such mass and dimensions as to give the minimum amount of flow and spew ii mouldmg. the spew being of even thickness all round the test piece. Wherever possible, any grain in the material shall run along the length of each test piece.
Remove each test piece from the mould with the minimum of bending and flexing. Remove any adhering spew from the electrodes, taking care not to buff or abrade the test piece, and ensure that the electrodes present a clean surface to the test leads. Relect any test piece showing evidence of insufficient mould filling, poor adhesion to the electrodes or any other defect.
Ensure that the surfaces of each test piece are clean by rubbing, where necessary, with Fullers earth and water, washing with distilled water and allowing to dry.
Do not clean the test pieces with organic materials which would attack or swell the rubber.
NOTE Bonding to brass is more easily achieved with conventional vulcanized rubber and might not be successful
with thermoplastic rubbers.
4.3 Number of test pieces
Three test pieces shall be prepared and tested.
4,4 Procedure
Allow the test piece to rest for not less than 16 h after vulcanization or moulding, in accordance with ISO 23529.
Place each test piece on one of the sheets of insulating material and heat in the oven for 2 h! 15 mm at a temperature 01(70 t 2) C, to minimize the effects of strain caused by any previous treatment. Allow to cool and condition at standard laboratory temperature and humidity in accordance with ISO 23529 for not less than 16 h. Do not strain the test pieces after heating and before the test has been completed.
After conditioning each test piece, and without removing it from its sheet of insulating material, measure, using the resistance-measuring instrument, the resistance between the bonded electrodes of each test piece in turn at the same standard temperature and humidity as was used to condition the test pieces.
5 Method 3
5.1 Apparatus and materials
51.1 Colloidal graphite, dispecsn in water.
5.1.2 Tin foil strIp. 5mm wide and about 25 urn thicl.
5.1.3 ResIstance-measurIng instrument. Any suitable resistance-measuring Instrument which does not dissipate more than 30 pW/mn1 in the test piece.
5.1.4 Sheets of insulating material with a volume resistivity greater than 1013 flm and a surface resistivity greater than 1014 ci.
5.1.5 Oven, capable of being controlled at (70 ±2) °C.
5.2 Test piece
Each test piece shall be a rectangular stflp of vulcanized or thermoplastic rubber with the dimensions given In Table 1 and shown in Figure 4. The thickness of the test pece shall be measured at six equally spaced points along Its length and no individual measurement shall vary by more than 5 % from the mean value.
NOTE Resiits obtained from the test might vary depending on the orIentation at any grain lithe material with respect to the length 4 shown in Figure 4.
