BS ISO 4658:2020 pdf free.Acrylonitrile-butadiene rubber (NBR)一Evaluation procedure.
BS ISO 4658 The mixing technique in each method may be modified to achieve a good dispersion of all the ingredients. The LIM conditions shall be the same during the preparation of a series of identical mixes for each batch mixed. At the beginning of each series of test mixes, a machine-conditioning batch shall be mixed using the same formulation as the mixes under test. The LIM shall be allowed to cool down to 60 °C between the end of one test batch and the start of the next. Temperature control condition shall not be altered during the mixing of a series of test.The final temperature of the batch discharged after mixing shall not exceed 120 °C. If necessary, adjust the batch mass, head temperature or rotors speed, so that this condition is met.Compounding materials other than rubber, carbon black and oil may be added to LIM batches more precisely and with greater ease if they are previously blended together in the proportions required by the formulation. Such blends may be made using a mortar and pestle, by mixing for 10 min in a biconical blender with intensifier bar turning, or by mixing in a blender for five 3 s periods and scraping the inside of the blender to dislodge materials stuck to the sides after each 3 s mix. A waring blender has been found suitable for this method.A type 2 (interlaboratory) precision was determined. Three different materials or rubbers were used in
the interlaboratory programme. These were tested in seven laboratories on two different days.The calculated repeatability and reproducibility values are given in Table A.1.a] Repeatability: the two test results are obtained with the same method on nominally identical test materials under the same conditions (same operator, apparatus and laboratory) and within a specified time period. Unless stated otherwise, the probability is 95 %.b) Reproducibility: the two test results are obtained with the same method on nominally identical test materials under different conditions (different operators, apparatus and laboratories) and within a specified time period. Unless stated otherwise, the probability is 95 %.BS ISO 4658 pdf download.