ASTM D471 Standard Test Method for Rubber Property - Effect of Liquids
5. Test Conditions
5.1 Temperature and Immersion Periods - Unless otherwise specified the test temperature and immersion period shall be as indicated in Table 1, depending upon the anticipated service conditions:
5.1.1 When the temperature of the testing room is other than the standard 23 +/- 2°C (73 +/- 4°F) the temperature of test shall be reported.
5.1.2 The choice of the immersion period will depend upon the nature of the vulcanizate, the test temperature, and the liquid to be used. To obtain information on the rate of deterioration it is necessary to make determinations after several immersion periods. The tolerance for any immersion period shall be +/-15 min or +/-1 % of the immersion period, whichever is greater.
5.2 Illumination - Immersion tests shall be made in the absence of direct light.
6. Standard Test Liquids
6.1 For test purposes, it is usually desirable to use the liquid that will come into contact with the vulcanizate in service. For comparative tests with liquids of unknown or doubtful composition, samples of liquid from the same container or shipment shall be used. Many commercial products, particularly those of petroleum origin, are subject to sufficient variation that it is not practical to use them for test liquids. It is then advisable to use a standard test liquid, such as described in 6.1.1 and 6.1.2, covering the range of properties that may be encountered in the particular service.
6.1.1 ASTM and IRM Oils - The test shall be conducted in one of the petroleum-base ASTM or IRM oils (Note 1) specified in Table 2 that has its aniline point nearest that of the oil with which the vulcanizate is expected to come in contact in service except as indicated in 6.1.3.
NOTE 1 - The aniline point of a petroleum oil appears to characterize the swelling action of that oil on rubber vulcanizates. In general, the lower the aniline point, the more severe the swelling action by the oil. The oils specified in Table 2 cover a range of aniline points commonly found in lubricating oils.
6.1.2 ASTM Reference Fuels - When gasolines or diesel fuels are to be encountered in service, the test shall be conducted in one of the ASTM reference fuels (Note 2) specified in Table 3, except as indicated in 6.1.3.
NOTE 2 - The ASTM reference fuels in Table 3 have been selected to provide the maximum and minimum swelling effects produced by commercial gasolines. Reference Fuel A has a mild action on rubber vulcanizates and produces results of the same order as low swelling gasolines of the highly paraffinic, straight run type. Reference Fuels B, C, and D simulate the swelling behavior of the majority of commercial gasolines, with Reference Fuel C producing the highest swelling which is typical of highly aromatic premium grades of automotive gasoline. Reference Fuel F (diesel fuel) swells rubber vulcanizates to a lesser extent than Reference Fuel B. Reference Fuels G, H, and I are fuel-alcohol blends (gasohol), which have a stronger swelling action than the corresponding fuel alone, where blends with methanol are more severe than blends with ethanol. Reference Fuel K, a methanol-rich blend, has a substantially weaker swelling action than that of the fuel used to prepare the blend. Reference Fuels I and K are also referred to as M15 and M85, respectively.
6.1.3 Service Liquids - Some commercial oils, fuels and other service liquids (see Table 4) are either non-petroleum or are compounded from special petroleum hydrocarbon fractions or mixtures of petroleum hydrocarbon fractions and other ingredients resulting in materials having properties beyond the range of the reference fluids listed in Table 2 and Table 3. Immersion tests of rubber vulcanizates that are to come into contact with such fluids should be made in the actual service liquid.
6.1.4 Water - Since the purity of water varies throughout the world, all water immersion tests are to be conducted in distilled or deionized water.
7. Preparation of Specimen
7.1 Except as otherwise specified in the applicable specifications, specimens shall be prepared in accordance with the requirements of Practices D3182 and D3183.
