1、Designation: D 4733 03An American National StandardStandard Test Methods forSolventless Electrical Insulating Varnishes1This standard is issued under the fixed designation D 4733; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 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 solventless varnishes usedprimarily as electrical, mechanical, and environmental pr
3、otec-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. The following tes
4、t 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-Using Metal Panel
5、s 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 is theresponsi
6、bility 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 methodscontain
7、multiple test procedures, many procedures are technically equiva-lent while others differ significantly.2. Referenced Documents2.1 ASTM Standards:2D 93 Test Methods for Flash-Point by Pensky-MartensClosed Cup TesterD 115 Test Methods for Testing Solvent Containing Var-nishes Used for Electrical Insu
8、lationD 149 Test Method for Dielectric Breakdown Voltage andDielectric Strength of Solid Electrical Insulating Materialsat Commercial Power FrequenciesD 150 Test Methods for A-C Loss Characteristics andPermittivity (Dielectric Constant) of Solid Electrical Insu-lating MaterialsD 168 Test Method for
9、Coke Residue of CreosoteD 374 Test Methods for Thickness of Solid Electrical Insu-latioD 923 Test Method for Sampling Electrical Insulating Liq-uidsD 1475 Test Method for Density of Paint, Varnish, Lacquer,and Related ProductsD 1711 Terminology Relating to Electrical InsulationD 2196 Test Methods fo
10、r Rheological Properties of Non-Newtonian Materials by Rotational (Brookfield) Viscom-eterD 2519 Test Method for Bond Strength of Electrical Insu-lating Varnishes by the Helical Coil TestD 3056 Test Method for Gel Time of Solventless VarnishesD 3278 Test Method for Flash Point of Liquids by SmallSca
11、le Closed-Cup ApparatusD 3312 Test Method for Percent Reactive Monomer inSolventless VarnishesD 3487 Specification for Mineral Insulating Oil Used inElectrical Apparatus6D 3636 Practice for Sampling and Judging Quality of SolidElectrical Insulating MaterialsD 6054 Practice for Conditioning Electrica
12、l Insulating Ma-terials for Testing2.2 IEC StandardsIEC 60455 Resin Based Reactive Compunds Used for1These 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 Va
13、rnishes, Powders, and Encapsu-lating Compounds.Current edition approved Oct. 1, 2003. Published November 2003. Originallyapproved in 1987. Last previous edition approved in 1998 as D 4733 98.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serv
14、iceastm.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.Electrical Insulation3. Terminology3.1 Definitions: For
15、 definitions of terms used in these testmethods, refer to Terminology D 1711.3.1.1 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.3.1.2 thixotropy, nt
16、he 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 electrical components providingelectrical, mechanical, and environmental protection.3.1.3.1 DiscussionThere are t
17、wo 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 volatile, nonre-actable liquid. The solventless type is a liquid resin system freeof volatile, nonreactable solve
18、nts.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 sampling, whether of the complete contents oronly parts thereof, is extremely important from the standpointof
19、 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 particles, necessitates taking samples at specific locationswhere the contaminants are likely to be found. For
20、 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,these impurities are most likely to be found on the surface.5.2 Sampling Fluids Exhibiting Newtonian Viscosi
21、ty: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 D 923.However, if the temperature of the material is below roomtemperature or if the humidity is above 75 % relative humidity,samp
22、le using an aspirator-type sampling device as shown inFig. 2 of Test Method D 923.5.2.2 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
23、 Test Method D 923.5.2.3 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 Exhi
24、biting 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 Test Method D 923.5.5 When a sampling method is needed to determinewhether a lot meets the requirements of
25、 a material specifica-tion, use Practice D 3636 as a guide.6. Conditioning6.1 Condition test specimens at standard laboratory condi-tion as specified in Practice D 6054.6.2 Deaerate specimens to be used for property evaluationbefore curing using the vacuum technique recommended by thevarnish manufac
26、turer.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 of testingdensity. In this test method the density will be expressed aspounds per gallon (grams per m
27、illilitre) at 70 to 77F (20 to25C).7.2 ProcedureTest for density in accordance with TestMethod D 1475.7.3 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
28、.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 ofmaterials involved:8.1.1 Those varnishes having a flash point above 230F(110C), and8.1.2 Those varnishe
29、s 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 flameignites the vapor of the specimen in the tester and propagatesa flame across its surface. The te
30、mperature 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 conditions and should not be used todescribe or appraise the fire hazard or fire risk of materials,products
31、, 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 which are pertinent to an assessment of thefire hazard of a particular end use.8.4 Procedure:8.4.1 Test t
32、he materials of 8.1.1 in accordance with TestMethods D 93.8.4.2 Test the materials of 8.1.2 in accordance with TestMethod D 3278.D47330328.5 ReportReport information in accordance with thereport section of the test method used.9. Gel Time9.1 ScopeThis test method covers the determination ofgel time
33、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 uniformity, and processingcharacteristics.9.3 ProcedureTest for gel time in accordance with TestMethod D 3056.9.
34、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 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 b
35、ath.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 percent of reactive mono-mer in a solventless varnish will affect the viscosity, handling,and processing proper
36、ties 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 Test Method D 3312.10.4 ReportReport the following information:10.4.1 Identification of the solventless var
37、nish, 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 arenon-newtonian in character.11.2 Significance and UseThis test method is used to testsolventless varnish
38、es 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 D 2196, Method B or C.11.4 ReportReport information as specified in TestMethod D 2196.12. Brookfield Viscosity12.1 ScopeThi
39、s 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.12.2.3 Water Bath.12.2.4 Stirrer.12.3 Procedure:12.3.1 Bring the specimen to a temperature of 77 6 2F (256
40、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 viscom-eter at 77 6 2F (25 6 1.0C).12.4 ReportReport information as specified in TestMethod D 2196.12.
41、5 Precision and Bias:12.5.1 PrecisionSee Test Method D 2196 for a statementof precision.12.5.2 BiasSee Test Method D 2196 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.
42、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 prescribed conditions.13.3 ProcedurePerform the test in accordance with TestMethod D 2519.13.4 ReportR
43、eport information in accordance with TestMethod D 2519.13.5 Precision and Bias:13.5.1 PrecisionSee Test Method D 2519 for a statementof bias.13.5.2 BiasSee Test Method D 2519 for a statement ofbias.14. Coating Thickness14.1 Scope:14.1.1 This test method is used to determine the thickness ofa coating
44、 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 degree ofshear of the sample and the rate of withdrawal of the specimenin order to arrive at a
45、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 atemperature of 75 6 2F (24 6 1C).14.2.3 Thermometer, with a range of 32 to 212F (0 to100C).14.2.4 Tes
46、t 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 thethickness at 2 in. (50 mm) below the top and at 4 in. (100 mm)below the top. An average of these two is
47、the thickness of thebare panel. Thickness measurements shall be made in accor-dance with Test Methods D 374.14.3 Procedure:D473303314.3.1 Bring the test specimen to a temperature of 756 2F(24 6 1C) and pour slowly into a suitable container. Do nottrap air in the varnish.14.3.2 Slowly lower the test
48、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 conditionwithout vibration for 60 to 65 min.14.3.4 At the end of 60 min move the specimen under a dipcoater th
49、at 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 in an oven and bake in accor-dance with the manufacturers instructions. Be careful not tovibrate the speci
