BS ISO 188:2011 pdf download.Rubber, vulcanized or thermoplastic一Accelerated ageing and heat resistance tests.
Care shal be taken to ensure that me markings used to identify the test pieces are not pleed in any cracal area of the test piece arid will not damage the rubber or disappear during heating.
Avoid simultaneous heeling of different types of oonipound We the earns oven, to prevent the megredon of s*hur, anbozidants, peroxides or ptesbcizers For this purpose, the use of individual cells is highly recomemided. We order, however, to give some guidance for cases where I is not practicable to provide equlpmnerl wflh individual celts. It Is recommended that only the following types 01 matenal be heated together;
a) polymers of the same general type;
b) vulcanlzates centering the same type of accelerator and approximately the same ratio of sulphur to accelerator.
C) rtbers contaWshg the sante type of anbo.dent
d) rtbers comdawiang the sane type end arneunt of plasliazor.
7 Time interval between vulcanization and testing
Unless otherwise speaflea for techmcal reasons. the followIng requirements shal be observed
For ci normal test purpoe.s, the nwilmum bmn between vulcanization end testing shall be 16 Ii. We cases of arbitration, the minimum time shall be 72 h
For non-prOdijcl tests, the macamen bite between vticatization and testing shall be lout weeks and. for evaluations Intended to be comparable, the tests as lam as pos&tse. sha be carried it after the same hine’ interval.
For product tests, whenever posalile, the time between vulcanization and testing shall riot exceed ttwee monttw. We other cases, tests shall be made wiOwi two months 01 the date of recet by the purchaser of the prudixt.
8 Agelng conditions (duration and temperature)
8.1 General
The period reqi.à.d to obbin e given degree of d.brioratxin of lie lest pieces w depend e.çon the type of rubber under examination
The ageing period used sliotid pretery be suab that deterioration of the test pieces we not be so giwat as to prevent cfeter,vianataon 01 the final values of physical properties
The use of high ageing teniperabires may result ii lfererl degradation mechanisms that, those which occur at service temparatores, thos InvalIdating me restits
It Is aucial for the best results that the lemoperatese be k.pl as stabl, as possitse Temperature tolerances in ISO 23529 an 1 t t, to and lichidlig 100 C arid +2 C for 125 tt to arid enchiding 300 C. l4awever, studies have shown that a 1 C change In lempem-alise corresponds to a 10 % difference in ageng time an AMiemilus factor 012. or 15% at a factor of 2,& Thee means ttue two laboratories canylig out ageing at 125 C can have ag.Ireg tense which differ by 60% train .ad other and stat be within the specification To get aocurafe results, keep th. temperature as accurate as posatee by placing a cateraled temperature sensor close to the test pieces and use This to set the oven so Vial the tenerature at this position Is correct. Use the correction factor from the callwa5on cemlificate to get as close as possIe to tie true temperature.BS ISO 188 pdf download.