ASTM_D_411_-_98_2003.pdf

Designation:D 411 98(Reapproved 2003)An American National StandardStandard Test Methods forShellac Used for Electrical Insulation1This standard is issued under the fixed designation D 411;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 These test methods cover tests for shellac in the drybutton or powder form to be used for electrical insulatingpurposes.Typically,shellac is used as a bonding agent for micasplittings and reconstituted mica paper products,or as a coatingor adhesive for other material.1.2 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.NOTE1There is no similar or equivalent IEC standard.2.Referenced Documents2.1 ASTM Standards:2D 29 Test Methods for Sampling and Testing Lac ResinsD 1711 Terminology Relating to Electrical InsulationD 5032 Practice for Maintaining Constant Relative Humid-ity by Means of Aqueous Glycerine SolutionsD 6054 Practice for Conditioning Electrical Insulating Ma-terials for TestingE 104 Practice for Maintaining Constant Relative Humidityby Means of Aqueous Solutions3.Terminology3.1 Definitions:For definitions of terms used in this stan-dard,refer to Terminology D 1711.4.General Tests4.1 Each of the following tests shall be made in accordancewith the procedures described in Test Methods D 29:4.2 Sampling,4.3 Insoluble Matter,4.4 Iodine Number,4.5 Moisture Content,4.6 Wax,4.7 Ash,and4.8 Orpiment(Native arsenic trisulfide).POLYMERIZATION TIME5.Significance and Use5.1 Polymerization time provides a measure of time duringwhich shellac retains its plasticity and flow properties at thespecified temperature before gelling or polymerizing to thetough rubbery insoluble form.This test is important in deter-mining the quality of different lots,useful shelf-life,batchuniformity,and processing characteristics of shellac.6.Apparatus6.1 Test Tubes and Wire RackTwo 18-mm outside diam-eter glass test tubes,supported by a wire rack to a depth of 100mm when placed in an oil bath.The test tubes must besupported and maintained in a vertical position.The rack shallbe constructed so as to permit free circulation of oil around thetest tubes.6.2 Oil BathThe oil bath shall be constructed with heat-ers,temperature control,and means of circulation to maintainthe oil or other liquid at a temperature of 150 6 1C at allpoints within the bath.The oil or other liquid used shall beappropriate for the design of the bath and for safety at the testtemperature.The bath shall be equipped with a thermometer,orother indicator or recorder,to indicate the oil temperaturewithin 61C.6.3 Glass RodAsmooth glass rod about 3 mm in diameterand approximately 200 mm long.The end of the glass rodwhich is to be immersed in the shellac shall be fire polished toa smooth round end.NOTE2A smooth glass rod about 5 mm in diameter and approxi-mately 200 mm long with an indicator mark at the top to indicatemovement may be used.Flatten slightly the diameter of the glass rod forapproximately 3 mm length at the end which is immersed in the shellac.The purpose of the flattened rod is to provide a more positive feel of thetwist back and rubbery character at the end point.If this alternative isused,it must be specified in the report.1These methods are under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and are the direct responsibility ofSubcommittee D09.01 on Electrical Insulating Varnishes,Powders,and Encapsu-lating Compounds.Current edition approved Nov.10,1998.Published January 1999.Originallyapproved in 1935.Last previous edition approved in 1998 as D 411 98.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.6.4 Timer,for indicating elapsed time in minutes andseconds.7.Test Specimens7.1 For each test specimen use 4.00 6 0.01 g of shellac,dried as specified in 8.2.7.2 Prepare two specimens from each sample.8.Conditioning8.1 Crush samples of shellac on clean paper,mix well,andthen dry as described in 8.2.8.2 For each sample to be tested,evenly spread 9 to 10 g ofthe sample in a flat-bottom dish about 50 mm in diameter.Desiccate over anhydrous calcium chloride for at least 24 h atroom temperature,or dry in a forced-convection oven at atemperature of 40 6 2C for 16 to 20 h.8.3 After drying,immediately transfer the sample to a clean