ASTM_D_5669_-_95.pdf

Designation:D 5669 95Standard Test Method forRubberEvaluation of Residual Unsaturation inHydrogenated Nitrile Rubber(HNBR)by Curemeter Testing1This standard is issued under the fixed designation D 5669;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers a technique for evaluating aparameter,derived from curemeter testing of a standard hydro-genated nitrile rubber(HNBR)formulation,that is related tothe percent residual unsaturation of the HNBR.The standardmaterials,test formulation,and mixing procedure are fullydescribed.This test method is applicable to all grades of HNBRin the raw unvulcanized state.1.2 The evaluation of the unsaturation parameter,desig-nated by UP,is based on special regression equations devel-oped from the measured values for two curemeter parametersversus the percent unsaturation measured by infrared spectro-photometry as defined by Test Method D 5670.The data usedfor this are contained in Appendix X1.1.2.1 The use of a curemeter and a standard formulation toevaluate the residual unsaturation in HNBR has the advantageof being a relatively simple test,available to most rubbertesting laboratories.The disadvantage lies in the nonlinearrelationship between HNBR unsaturation and the measuredcuremeter parameters of scorch time,tS1 and maximumcuremeter torque,MH.1.2.2 The use of UP,which is calculated from a scorch timeparameter and a maximum torque parameter,both of which areobtained from Table A1.1 permits the development of a morerealistic relationship of the unsaturation levels among a groupof HNBR samples than the less definitive technique of simpleranking.The ranking technique is not definitive because therelationship between the curemeter parameters and the unsat-uration is highly nonlinear.Curemeter ranking of a series ofHNBR samples at low true unsaturation compared to theranking of a series of samples at high true unsaturation,maygive misleading indications of unsaturation differences amongthe group of rubbers.1.2.3 If,U,the unsaturation in percent of a tested HNBRsample is known,it can be used to calculate the approximateunsaturation(in percent)of unknown HNBR samples.1.3 Mixing and curemeter testing variations,both withinand between laboratories,may influence the results as obtainedby this test method.These variations will be smaller forwithin-laboratory testing.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:D 2084 Test Method for Rubber PropertyVulcanizationUsing Oscillating Disk Cure Meter2D 3182 Practice for RubberMaterials,Equipment andProcedures for Mixing Standard Compounds and Prepar-ing Standard Vulcanized Sheets2D 5289 Test Method for Rubber PropertyVulcanizationUsing Rotorless Cure Meters2D 5670 Test Method for RubberDetermination of Re-sidual Unsaturation in Hydrogenated Nitrile Rubber(HNBR)by Infrared Spectrophotometry23.Summary of Test Method3.1 Separate compounds using different samples of HNBRare prepared in a Miniature Internal Mixer(MIM).One ormore compound(s)contain(s)the experimental or candidateHNBR sample(s)to be evaluated and the other compound(s)contain(s)HNBR sample(s)of known residual unsaturation.3.2 The maximum torque and scorch times of the formula-tions are used to evaluate the UP of HNBR samples withunknown unsaturation.If samples of HNBR with knownunsaturation are also evaluated,the measured UP of thesesamples may be used to obtain the approximate unsaturation inpercent,of the unknown samples.3.3 Lower maximum torque and longer scorch and curetimes indicate lower residual unsaturation.4.Significance and Use4.1 Hydrogenated nitrile rubbers are available at differentlevels of unsaturation and different acrylonitrile content.Highly saturated grades offer optimum resistance to aging,such as exposure to heat,ozone,and chemicals,and can onlybe vulcanized effectively with peroxides or high energy radia-tion.1This test method is under the jurisdiction ofASTM Committee D-11 on Rubberand is the direct responsibility of Subcommittee D11.23 on Synthetic Rubbers.Current edition approved Feb.15,1995.Published April 1995.2Annual Book of ASTM Standards,Vol 09.01.1AMERICAN SOCIETY FOR TESTING AND MATERIALS100 Barr Harbor Dr.,West Conshohocken,PA 19428Reprinted from the Annual Book of ASTM Standards.Copyright ASTMNOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.4.2 Partially unsaturated grades can be cured by sulfurs