1、Designation: D4733 13Standard Test Methods forSolventless Electrical Insulating Varnishes1This standard is issued under the fixed designation D4733; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe
2、r 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 solventless varnishes usedprimarily as electrical, mechanical, and environmental protec-tion for electrical equipm
3、ent.1.2 These test methods are used on solventless varnishesthat are applied by dipping (at atmospheric pressure conditionsor under vacuum or other certain pressure), spraying, orbrushing for the purpose of impregnating or sealing electricalequipment. The following test methods are included:Property
4、 Tests (Uncured): SectionDensity 7Flash Point 8Gel Time 9Monomer Content 10Rheological Properties (Non-Newtonian) 11Brookfield Viscosity 12Performance Property Tests (cured):Bond Strength 13Coating Thickness 14Dielectric Strength 15Dielectric Strength-Using Metal Panels 16Permittivity and Dissipatio
5、n Factor 17Build 181.3 The values stated in inch-pound units are to be regardedas the standard. The values in parentheses are for informationonly.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 stan
6、dard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific hazardstatements are given in 8.3, 15.5.1, and 15.5.2.NOTE 1This test method is related to IEC 60455. Since both methodscontain multiple test procedures, many
7、procedures are technically equiva-lent while others differ significantly.2. Referenced Documents2.1 ASTM Standards:2D93 Test Methods for Flash Point by Pensky-MartensClosed Cup TesterD115 Test Methods for Testing Solvent Containing Var-nishes Used for Electrical InsulationD149 Test Method for Dielec
8、tric Breakdown Voltage andDielectric Strength of Solid Electrical Insulating Materialsat Commercial Power FrequenciesD150 Test Methods for AC Loss Characteristics and Permit-tivity (Dielectric Constant) of Solid Electrical InsulationD168 Test Method for Coke Residue of Creosote (With-drawn 2006)3D37
9、4 Test Methods for Thickness of Solid Electrical Insu-lation (Withdrawn 2013)3D923 Practices for Sampling Electrical Insulating LiquidsD1475 Test Method For Density of Liquid Coatings, Inks,and Related ProductsD1711 Terminology Relating to Electrical InsulationD2196 Test Methods for Rheological Prop
10、erties of Non-Newtonian Materials by Rotational (Brookfield type)ViscometerD2519 Test Method for Bond Strength of Electrical Insulat-ing Varnishes by the Helical Coil TestD3056 Test Method for Gel Time of Solventless VarnishesD3278 Test Methods for Flash Point of Liquids by SmallScale Closed-Cup App
11、aratusD3312 Test Method for Percent Reactive Monomer in Sol-ventless VarnishesD3487 Specification for Mineral Insulating Oil Used inElectrical ApparatusD3636 Practice for Sampling and Judging Quality of SolidElectrical Insulating MaterialsD6054 Practice for Conditioning Electrical Insulating Mate-ri
12、als for Testing (Withdrawn 2012)3E176 Terminology of Fire Standards1These test methods are under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.01 on Electrical Insulating Varnishes, Powders and Encapsulat-i
13、ng Compounds.Current edition approved April 1, 2013. Published April 2013. Originallyapproved in 1987. Last previous edition approved in 2009 as D4733 03 (2009).DOI: 10.1520/D4733-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.
14、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,
15、 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.2 IEC StandardsIEC 60455 Resin Based Reactive Compunds Used for Elec-trical Insulation3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in these test methods,refer to Terminology D1711. For definit
16、ions of terms associ-ated with fire issues, refer to Terminology E176.3.1.2 gel time, nof solventless varnish, the time requiredat a specified temperature for a solventless varnish to betransformed from a liquid state to a gel as measured with asuitable gel time apparatus.3.1.3 thixotropy, nthe prop
17、erty of a material to thin uponisothermal agitation and to thicken upon subsequent rest.3.1.4 varnish, electrical insulating, na liquid resin systemthat is applied to and cured on electrical components providingelectrical, mechanical, and environmental protection.3.1.4.1 DiscussionThere are two type
18、s of electrical insu-lating varnishsolvent-containing and solventless. Thesolvent-containing varnish is solution, dispersion, or emulsionof a polymer or a mixture of polymers in a volatile, nonre-actable liquid. The solventless type is a liquid resin system freeof volatile, nonreactable solvents.4.
19、Significance and Use4.1 The test methods referenced in these test methods areuseful for control purposes during the manufacture and use ofsolventless varnishes.5. Sampling5.1 Accurate sampling, whether of the complete contents oronly parts thereof, is extremely important from the standpointof evalua
20、ting the quality of the product sampled. In most cases,the detection of contaminants that are not ordinarily disperseduniformly through the liquid being sampled such as water orsolid particles, necessitates taking samples at specific locationswhere the contaminants are likely to be found. For a liqu
21、idhaving a specific gravity less than one, water and otherimpurities are most likely to be found on the bottom; whereasin the case of liquids having a specific gravity greater than one,these impurities are most likely to be found on the surface.5.2 Sampling Fluids Exhibiting Newtonian Viscosity:5.2.
22、1 Sample solventless varnishes having an approximateviscosity of 25 cP (0.025 Pas) or less at 100F (37.8C) usingthe sampling device shown in Fig. 1 of Test Method D923.However, if the temperature of the material is below roomtemperature or if the humidity is above 75 % relative humidity,sample using
23、 an aspirator-type sampling device as shown inFig. 2 of Test Method D923.5.2.2 Sample solventless varnishes having a viscosity from25 to 650 cP (0.025 to 0.65 Pas) at 100F (37.8C) and wherecontact with the atmosphere must be avoided, use a pressure-type sampling device as shown in Fig. 3 of Test Met
24、hod D923.5.2.3 Sample solventless varnishes having a viscosity above650 cP at 100F at 73 6 10F (23 6 5C). Open the containerand mix slowly so as not to entrap air. When the material ishomogeneous, take samples from two or three places on thesurface and mix together.5.3 Sampling Fluids Exhibiting Non
25、-Newtonian Viscosity:5.3.1 Sample solventless varnishes exhibiting non-Newtonian viscosity in accordance with 5.2.3.5.4 Use sample containers and sampling procedures inaccordance with Test Method D923.5.5 When a sampling method is needed to determinewhether a lot meets the requirements of a material
26、specification, use Practice D3636 as a guide.6. Conditioning6.1 Condition test specimens at standard laboratory condi-tion as specified in Practice D6054.6.2 Deaerate specimens to be used for property evaluationbefore curing using the vacuum technique recommended by thevarnish manufacturer.TEST METH
27、ODS7. Density7.1 ScopeThis test method covers the measurement of thedensity using a pycnometer. It is particularly applicable wherethe fluid has too high a viscosity for other methods of testingdensity. In this test method the density will be expressed aspounds per gallon (grams per millilitre) at 7
28、0 to 77F (20 to25C).7.2 ProcedureTest for density in accordance with TestMethod D1475.7.3 ReportReport the following information:7.3.1 Identification of the test sample,7.3.2 The test temperature to the nearest 0.2F (0.1C),7.3.3 Density to the nearest 0.01 lb/gal (0.001 g/mL), and7.3.4 The mean, the
29、 range, and the number of replicatedeterminations.8. Flash Point8.1 ScopeThis test method covers the determination of theflash point of solventless varnishes. There are two types ofmaterials involved:8.1.1 Those varnishes having a flash point above 230F(110C), and8.1.2 Those varnishes having a flash
30、 point below 230F(110C).8.2 Summary of Test MethodAspecified amount of sampleis added to the instrument. The temperature of the material isincreased at a constant rate until a small flame ignites the vaporof the specimen in the tester and propagates a flame across itssurface. The temperature at igni
31、tion is taken as the flash point.8.3 This standard is used to measure and describe theresponse of materials, products, or assemblies to heat andflame under controlled conditions, but does not by itselfincorporate all factors required for fire hazard or fire riskassessment of the materials, products
32、or assemblies underactual fire conditions.D4733 1328.4 Fire testing is inherently hazardous. Adequate safe-guards for personnel and property shall be employed inconducting these tests.8.5 Procedure:8.5.1 Test the materials of 8.1.1 in accordance with TestMethods D93.8.5.2 Test the materials of 8.1.2
33、 in accordance with TestMethod D3278.8.6 ReportReport information in accordance with thereport section of the test method used.9. Gel Time9.1 ScopeThis test method covers the determination of geltime of a solventless varnish mixed with a reactor or catalystand exposed to elevated temperatures.9.2 Si
34、gnificance and UseKnowledge of gel time is impor-tant for determining shelf life, batch uniformity, and processingcharacteristics.9.3 ProcedureTest for gel time in accordance with TestMethod D3056.9.4 ReportReport the following information:9.4.1 Identification of the material,9.4.2 The reactor or ca
35、talyst and quantity used shall bedescribed if the reactor or catalyst is supplied in a separatepackage,9.4.3 Gel time to the nearest 0.1 min,9.4.4 Temperature of the bath, and9.4.5 Liquid used in the bath.10. Monomer Content10.1 ScopeThis test method covers the determination ofthe percent monomer ha
36、ving a vapor pressure exceeding 0.1Torr (13 Pa) at 77F (25C).10.2 Significance and UseThe percent of reactive mono-mer in a solventless varnish will affect the viscosity, handling,and processing properties of the uncured resin. The amount ofreactive monomer also has the potential to affect the physi
37、caland electrical properties of the cured resin.10.3 ProcedureTest for the monomer content in accor-dance with Test Method D3312.10.4 ReportReport the following information:10.4.1 Identification of the solventless varnish, and10.4.2 Percent reactive monomer.11. Rheological Properties (Non-Newtonian)
38、11.1 ScopeThis test method covers the determination ofthe rheological properties of solventless varnishes that arenon-newtonian in character.11.2 Significance and UseThis test method is used to testsolventless varnishes that are thixotropic in nature and requirespecific treatment of the sample in or
39、der to determine thisproperty.11.3 ProcedureTest for thixotropy in accordance with TestMethod D2196, Method B or C.11.4 ReportReport information as specified in TestMethod D2196.12. Brookfield Viscosity12.1 ScopeThis test method covers the determination ofviscosity for liquids having flow properties
40、 approaching thoseof the newtonian solutions.12.2 Apparatus:12.2.1 Brookfield Viscometer.12.2.2 Thermometer.12.2.3 Water Bath.12.2.4 Stirrer.12.3 Procedure:12.3.1 Bring the specimen to a temperature of 77 6 2F (256 1.0C) using a water bath and stirrer if necessary. Allow thespecimen to sit in the wa
41、ter bath at 77 6 2F until no bubblesare visible in the specimen.12.3.2 Make all measurements with the Brookfield viscom-eter at 77 6 2F (25 6 1.0C).12.4 ReportReport information as specified in TestMethod D2196.12.5 Precision and Bias:12.5.1 PrecisionSee Test Method D2196 for a statementof precision
42、.12.5.2 BiasSee Test Method D2196 for a statement ofbias.13. Bond Strength13.1 ScopeThis test method covers the determination ofthe bond strength of an electrical insulating varnish whenapplied to a helical coil.13.2 Significance and UseValues obtained by flexural testcan provide information with re
43、gard to the bond strength of aparticular varnish in combination with a particular wire whenmeasured under the prescribed conditions.13.3 ProcedurePerform the test in accordance with TestMethod D2519.13.4 ReportReport information in accordance with TestMethod D2519.13.5 Precision and Bias:13.5.1 Prec
44、isionSee Test Method D2519 for a statementof bias.13.5.2 BiasSee Test Method D2519 for a statement ofbias.14. Coating Thickness14.1 Scope:14.1.1 This test method is used to determine the thickness ofa coating obtained with a solventless varnish.14.1.2 The shear history of the varnish immediately pre
45、ced-ing the test has the potential to have an appreciable effect onthe coating thickness obtained. This test method specifies thedegree of shear of the sample and the rate of withdrawal of thespecimen in order to arrive at a reproducible buildup on a testspecimen.D4733 13314.2 Apparatus:14.2.1 Devic
46、e, capable of withdrawing a specimen at ap-proximately 4 in./min (100 mm/min).14.2.2 Water Bath, or conditioned room controlled to atemperature of 75 6 2F (24 6 1C).14.2.3 Thermometer, with a range of 32 to 212F (0 to100C).14.2.4 Test Panel, consisting of a steel or aluminum strip 3in. (75 mm) in wi
47、dth, 5 in. (125 mm) in length, and0.0050.032 in. (0.120.81 mm) in thickness.14.2.4.1 The thickness is determined by measuring thethickness at 2 in. (50 mm) below the top and at 4 in. (100 mm)below the top. An average of these two is the thickness of thebare panel. Thickness measurements shall be mad
48、e in accor-dance with Test Methods D374.14.3 Procedure:14.3.1 Bring the test specimen to a temperature of 75 6 2F(24 6 1C) and pour slowly into a suitable container. Do nottrap air in the varnish.14.3.2 Slowly lower the test panel into the varnish.14.3.3 Place the container with the varnish and pane
49、l in aconstant-temperature water bath or in a conditioned room heldat 75 6 2F (24 6 1C). Allow it to stand in this conditionwithout vibration for 60 to 65 min.14.3.4 At the end of 60 min move the specimen under a dipcoater that has been previously adjusted to withdraw thespecimen at a rate of approximately 4 in./min (100 mm/min).Attach the specimen without disturbing the jar or panel.14.3.5 After the panel has been raised out of the varnish,stop the dip coater and allow the panel to stand for 30 min.Move the conta
