BS ISO 4662:2017 pdf download – Rubber, vulcanized or thermoplastic — Determination of rebound resilience
5.2.2 Dimensions
The standard test piece is a disc with a thickness of (12,5 ± 0,5) mm and a diameter of (29 ± 0,5) mm. Other test pieces having non-standard dimensions may be used for comparative measurements with special provisions (see Annex A). 5.2.3 Measurement of dimensions Check that the test pieces meet the requirements in 5.2.2, using the appropriate method of measurement described in ISO 23529.
5.2.4 Number of test pieces
For each material, two test pieces shall be tested.
5.2.5 Time-interval between forming and testing Samples and test pieces shall be protected from light and heat as much as possible during the interval between forming (vulcanization or moulding) and testing. For normal test purposes, the minimum time between forming and testing shall be 16 h. In cases of arbitration, the minimum time shall be 72 h. For non-product tests, the maximum time between forming and testing shall be four weeks and, for evaluations intended to be comparable, the tests shall, as far as possible, be carried out after the same time interval. For product tests, whenever possible, the time between forming and testing shall not exceed three months. In other cases, tests shall be made within two months of the date of receipt of the product by the purchaser (see ISO 23529). If the preparation of the test piece involves buffing, the interval between buffing and testing shall be not less than 3 h and not greater than 72 h. 5.2.6 Conditioning Prepared test pieces shall be conditioned immediately before testing for a minimum period of 3 h at one of the standard laboratory temperatures specified in ISO 23529.
The same temperature shall be used throughout any one test or series of tests intended to be comparable. 5.3 Temperature of test The temperature or temperature range of the test shall be chosen according to the material being tested and the information required. Preference shall be given to the temperatures listed in ISO 23529. The tolerance limits on the temperature shall be not more than ±1 °C. When no temperature is specified, a standard laboratory temperature shall be chosen. Where the resilience changes quickly with temperature, the use of more temperatures at closer intervals is recommended.
5.4 Procedure
5.4.1 Thermal conditioning and mounting of test piece If stickiness is noted on the impacted surface, its effect shall be avoided by dusting the surface lightly, for example, with talc. If the test temperature differs from the standard laboratory temperature chosen (see 5.3), first bring the complete test apparatus, or the special heated or cooled holder (see 5.1.5), to the test temperature.
Mount the test piece in the holder and allow sufficient time for the test piece to reach a uniform temperature within the prescribed tolerance limits (see ISO 23529). Alternatively, test pieces may be heated or cooled separately from the holder in an oven or cold chamber in accordance with ISO 23529 and then quickly inserted in the heated or cooled holder. In this case, the time in the holder before testing shall preferably be reduced to 3 min. In tests at low temperatures, provision shall be made to prevent frost from forming on the test piece.
5.4.2 Mechanical conditioning of test piece After applying the prescribed thermal conditioning and mounting the test piece in the holder, carry out a mechanical conditioning by subjecting the test piece to a number of successive impacts between three minimum and seven as maximum, so as to reach a practically constant rebound amplitude.
5.4.3 Measurement of rebound resilience Immediately after the impacts for mechanical conditioning, carry out three more impacts on the test piece and note the three rebound readings.
5.4.4 Calculation and expression of results
Where no corrections are necessary, calculate the rebound resilience using the appropriate formula in 5.1.3.BS ISO 4662 pdf download.