1、Designation: D4733 03 (Reapproved 2009)An American National StandardStandard 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
2、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. Scope1.1 These test methods cover solventless varnishes usedprimarily as electrical, mechanical, and e
3、nvironmental protec-tion for electrical equipment.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. Th
4、e following test methods are included:Property 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-Us
5、ing Metal Panels 16Permittivity and Dissipation 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
6、 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. 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
7、methodscontain multiple test procedures, many 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 El
8、ectrical InsulationD149 Test Method for Dielectric Breakdown Voltage andDielectric Strength of Solid Electrical Insulating Materialsat Commercial Power FrequenciesD150 Test Methods for AC Loss Characteristics and Per-mittivity (Dielectric Constant) of Solid Electrical Insula-tionD168 Test Method for
9、 Coke Residue of Creosote3D374 Test Methods for Thickness of Solid Electrical Insu-lationD923 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 Rheol
10、ogical Properties of Non-Newtonian Materials by Rotational (Brookfield type) Vis-cometerD2519 Test Method for Bond Strength of Electrical Insu-lating Varnishes by the Helical Coil TestD3056 Test Method for Gel Time of Solventless VarnishesD3278 Test Methods for Flash Point of Liquids by SmallScale C
11、losed-Cup ApparatusD3312 Test Method for Percent Reactive Monomer inSolventless VarnishesD3487 Specification for Mineral Insulating Oil Used inElectrical ApparatusD3636 Practice for Sampling and Judging Quality of SolidElectrical Insulating MaterialsD6054 Practice for Conditioning Electrical Insulat
12、ing Ma-terials for Testing1These 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-ing Compounds.Current edition approved Oct
13、. 1, 2009. Published February 2010. Originallyapproved in 1987. Last previous edition approved in 2003 as D4733 03. DOI:10.1520/D4733-03R09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volum
14、e information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2.2 IEC Sta
15、ndardsIEC 60455 Resin Based Reactive Compunds Used forElectrical Insulation3. Terminology3.1 Definitions: For definitions of terms used in these testmethods, refer to Terminology D1711.3.1.1 gel time, nof solventless varnish, the time requiredat a specified temperature for a solventless varnish to b
16、etransformed from a liquid state to a gel as measured with asuitable gel time apparatus.3.1.2 thixotropy, nthe property of a material to thin uponisothermal agitation and to thicken upon subsequent rest.3.1.3 varnish, electrical insulating, na liquid resin systemthat is applied to and cured on elect
17、rical components providingelectrical, mechanical, and environmental protection.3.1.3.1 DiscussionThere are two types 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 volat
18、ile, nonre-actable liquid. The solventless type is a liquid resin system freeof volatile, nonreactable solvents.4. 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 s
19、ampling, whether of the complete contents oronly parts thereof, is extremely important from the standpointof evaluating 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 pa
20、rticles, necessitates taking samples at specific locationswhere the contaminants are likely to be found. For a liquidhaving 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,
21、these impurities are most likely to be found on the surface.5.2 Sampling Fluids Exhibiting Newtonian Viscosity:5.2.1 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 t
22、emperature of the material is below roomtemperature or if the humidity is above 75 % relative humidity,sample using 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 w
23、herecontact with the atmosphere must be avoided, use a pressure-type sampling device as shown in Fig. 3 of Test Method 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 ish
24、omogeneous, take samples from two or three places on thesurface and mix together.5.3 Sampling Fluids Exhibiting Non-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 T
25、est Method D923.5.5 When a sampling method is needed to determinewhether a lot meets the requirements of a material specifica-tion, 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
26、used for property evaluationbefore curing using the vacuum technique recommended by thevarnish manufacturer.TEST METHODS7. 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
27、 of testingdensity. In this test method the density will be expressed aspounds per gallon (grams per millilitre) at 70 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
28、 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 range, and the number of replicatedeterminations.8. Flash Point8.1 ScopeThis test method covers the determination ofthe flash point of solventless varnishes. There are two types ofma
29、terials involved:8.1.1 Those varnishes having a flash point above 230F(110C), and8.1.2 Those varnishes having a flash point below 230F(110C).8.2 Summary of Test MethodA specified amount ofsample is added to the instrument. The temperature of thematerial is increased at a constant rate until a small
30、flameignites the vapor of the specimen in the tester and propagatesa flame across its surface. The temperature at ignition is takenas the flash point.8.3 This test method should be used to measure and describethe response of materials, products, or assemblies to heat andflame under controlled condit
31、ions and should not be used todescribe or appraise the fire hazard or fire risk of materials,products, or assemblies under actual fire conditions. However,results of this test may be used as elements of a fire hazardassessment or a fire risk assessment which takes into accountall of the factors whic
32、h are pertinent to an assessment of thefire hazard of a particular end use.8.4 Procedure:8.4.1 Test the materials of 8.1.1 in accordance with TestMethods D93.D4733 03 (2009)28.4.2 Test the materials of 8.1.2 in accordance with TestMethod D3278.8.5 ReportReport information in accordance with therepor
33、t section of the test method used.9. Gel Time9.1 ScopeThis test method covers the determination ofgel time of a solventless varnish mixed with a reactor orcatalyst and exposed to elevated temperatures.9.2 Significance and UseKnowledge of gel time is impor-tant for determining shelf life, batch unifo
34、rmity, 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 catalyst and quantity used should bestated if the reactor or catalyst is supplied in a separate
35、package,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 having a vapor pressure exceeding 0.1Torr (13 Pa) at 77F (25C).10.2 Significance and UseThe perce
36、nt of reactive mono-mer in a solventless varnish will affect the viscosity, handling,and processing properties of the uncured resin. The amount ofreactive monomer may also affect the physical and electricalproperties of the cured resin.10.3 ProcedureTest for the monomer content in accor-dance with T
37、est 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)11.1 ScopeThis test method covers the determination ofthe rheological properties of solventless varnishes that a
38、renon-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 order to determine thisproperty.11.3 ProcedureTest for thixotropy in accordance withTest Method D2196, Method B or
39、 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 approaching thoseof the newtonian solutions.12.2 Apparatus:12.2.1 Brookfield Viscometer.12.2.2 Thermometer.12.2
40、.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 water bath at 77 6 2F until no bubblesare visible in the specimen.12.3.2 Make all measurements with the Brookfield
41、 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.12.5.2 BiasSee Test Method D2196 for a statement ofbias.13. Bond Strength13.1 ScopeThis test method covers the
42、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 regard to the bond strength of aparticular varnish in combination with a particular wire whenmeasured under the pr
43、escribed 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 PrecisionSee Test Method D2519 for a statementof bias.13.5.2 BiasSee Test Method D2519 for a statement ofbias.14. Co
44、ating 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 preced-ing the test may have an appreciable effect on the coatingthickness obtained. This test method specifies the
45、 degree ofshear of the sample and the rate of withdrawal of the specimenin order to arrive at a reproducible buildup on a test specimen.14.2 Apparatus:14.2.1 Device, capable of withdrawing a specimen at ap-proximately 4 in./min (100 mm/min).14.2.2 Water Bath, or conditioned room controlled to atempe
46、rature 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 width, 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 thethicknes
47、s 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 made in accor-dance with Test Methods D374.14.3 Procedure:D4733 03 (2009)314.3.1 Bring the test specimen to a temperature of 75 6 2F(24 6 1C
48、) 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 panel in aconstant-temperature water bath or in a conditioned room heldat 75 6 2F (24 6 1C). Allow it to stand in this condit
49、ionwithout 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 container away from the specimen so that thespecimen can hang free without detriment to the coating.14.3.6 Place the specimen
