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TM_D_411_
_08
Designation:D41108AnAmerican National StandardStandard Test Methods forShellac Used for Electrical Insulation1This standard is issued under the fixed designation D411;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()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 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 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 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equivalent IEC standard.2.Referenced Documents2.1 ASTM Standards:2D29 Test Methods for Sampling and Testing Lac Resins(Withdrawn 2005)3D1711 Terminology Relating to Electrical InsulationD5032 Practice for Maintaining Constant Relative Humidityby Means of Aqueous Glycerin SolutionsD6054 Practice for Conditioning Electrical Insulating Mate-rials for TestingE104 Practice for Maintaining Constant Relative Humidityby Means of Aqueous Solutions3.Terminology3.1 DefinitionsFor definitions of terms used in thisstandard,refer to Terminology D1711.4.General Tests4.1 Each of the following tests shall be made in accordancewith the procedures described in Test Methods D29:4.2 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 heaters,temperature control,and means of circulation to maintain theoil or other liquid at a temperature of 150 6 1C at all pointswithin the bath.The oil or other liquid used shall be appropriatefor the design of the bath and for safety at the test temperature.The bath shall be equipped with a thermometer,or otherindicator or recorder,to indicate the oil temperature within61C.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.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 Encapsulat-ing Compounds.Current edition approved May 1,2008.Published June 2008.Originallyapproved in 1935.Last previous edition approved in 2003 as D411 98(2003).DOI:10.1520/D0411-08.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesNOTICE:This standard has either been superseded and replaced by a new version or withdrawn.Contact ASTM International(www.astm.org)for the latest information1NOTE2It is permissible to use a smooth glass rod about 5 mm indiameter and approximately 200 mm long with an indicator mark at thetop to indicate movement.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,specify this in the report.6.4 Timer,for indicating elapsed time in minutes and sec-onds.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