1、Designation: D 3377 04An American National StandardStandard Test Method forWeight Loss of Solventless Varnishes1This standard is issued under the fixed designation D 3377; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 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 This test method covers the determination of the percentweight loss of cured solventless electrical varnishes whenex
3、posed to elevated temperatures for prescribed periods oftime.1.2 Results of this test method are based on 6-mm (14-in.)thick specimens and will not be applicable to specimensappreciably thinner or thicker than 6 mm.1.3 The values stated in SI units are to be regarded as thestandard.1.4 This standard
4、 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.NOTE 1This standard resembles IE
5、C 602162 “Guide for the deter-mination of thermal endurance properties of electrical insulating materi-als. Part 2: Choice of test criteria” in a number of ways, but is notconsistently similar throughout. The data obtained using either standardwill possibly be technically equivalent.2. Referenced Do
6、cuments2.1 ASTM Standards:2D 1711 Terminology Relating to Electrical InsulationD 5423 Specification for Forced-Convection LaboratoryOvens for Evaluation of Electrical Insulation2.2 IEC Standard:IEC 602162 Guide for the determination of thermal endur-ance properties of electrical insulating materials
7、. Part 2:Choice of test criteria33. Terminology3.1 Definitions:3.1.1 varnish, nelectrical insulating, a liquid resin systemthat is applied to and cured on electrical components providingelectrical, mechanical, and environmental protection.3.1.1.1 DiscussionThere are two types of electrical insu-lati
8、ng varnish: solvent-containing and solventless. The solvent-containing varnish is a solution, dispersion, or emulsion of apolymer or mixture of polymers in a volatile, nonreactableliquid. The solventless type is a liquid resin system free ofvolatile, nonreactable solvents.3.1.2 For definitions of ot
9、her terms relating to electricalinsulation, see Terminology D 1711.4. Significance and Use4.1 The amount and composition of by-products producedby exposure of insulating varnishes to elevated temperaturescan possibly:4.1.1 Deteriorate other insulations in the system,4.1.2 Cause cracking of insulatio
10、n due to pressure, buildupin thick cross sections, or4.1.3 Corrode other parts in the assembly.4.2 Amount and rate of weight loss will possibly affect thethermal rating of a varnish.5. Apparatus5.1 Metal Mold, consisting of two flat sheets 300 by 300 by6 mm (12 by 12 by14 in.) separated by 6.4 6 0.5
11、-mm (14 60.02-in.) thick spacers along three sides. The spacers also sealthe edges of the mold and the assembly is held together with“C” clamps or bolts. Aluminum or polished steel plates arepermissible.5.2 Laboratory Balance, with accuracy of 6 1 mg.5.3 Forced-Convection Laboratory Oven, meeting re
12、quire-ments of Specification D 5423, Type II for each test tempera-ture.5.4 Screening Platform, 6-mm (14-in.) mesh, with 50-mm(2-in.) legs.5.5 Mold Release.NOTE 2Fluorocarbon-type release agents are satisfactory.5.6 Desiccator.1This test method is under the jurisdiction of ASTM Committee D09 onElect
13、rical and Electronic Insulating Materials and is direct responsibility ofSubcommittee D09.01 on Electrical Insulating Varnishes, Powders, and Encapsu-lating Compounds.Current edition approved Sept. 1, 2004. Published September 2004. Originallyapproved in 1975. Last previous edition approved in 2000
14、as D 3377 00.2For 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.3Available from American National Standards Inst
15、itute, 11 W. 42nd St., 13thFloor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Procedure6.1 Apply a thin, uniform coating of release agent to thecontact surfaces of the mold.6.2 Assemble the mold, taking prec
16、autionary measures toavoid leaks.6.3 Pour the sample into the open edge of the mold, usingcare to avoid bubbles.NOTE 3In some cases, it will be necessary to prevacuum the samplebefore pouring.6.4 Cure the sample using the recommended cure cycle.6.5 After curing, remove the mold and contents from the
17、oven and allow to cool to room temperature.6.6 Carefully disassemble the mold and remove the castsheet.6.7 From the cast sheet, cut at least three specimensapproximately 50 by 50 mm (2 by 2 in.) for each testtemperature.6.8 Dry the specimens for 1 h 6 5 min at 110 6 2Ctoremove surface moisture.6.9 R
18、emove specimens from the oven and place themimmediately into the desiccator.6.10 After cooling to room temperature in the desiccator,weigh each specimen to the nearest 1 mg.6.11 Lay the specimens on the screen platform so that theyare at least 3 mm (18 in.) apart.6.12 Place the loaded platforms in t
19、he oven.6.13 Exposure Temperatures:Anticipated EndUse Temperature, C Temperature Range, C105 125 to 180130 150 to 200155 175 to 225180 200 to 250200 220 to 275220 250 to 300Choose three temperatures within the above ranges at least20 C apart.6.14 Exposure Times:Hours24 48 72 96 168NOTE 4If desired,
20、longer exposure times are permitted.6.15 After each test period, remove the specimens from theoven and place immediately into the desiccator to cool to roomtemperature.6.16 Weigh the specimens to the nearest 1 mg.7. Calculation7.1 Calculate the percent weight loss as follows:weight loss, % 5 A 2 B!/
21、A 3 100 (1)where:A = initial weight, andB = weight after thermal exposure period.8. Report8.1 Report the following information:8.1.1 Identity of compound,8.1.2 Cure cycle used, and8.1.3 Percent weight loss after each exposure period and foreach test temperature.9. Precision and Bias9.1 PrecisionThe
22、standard deviation of testing at fivelaboratories, for different times and temperatures, is shown inTable 1.49.2 BiasThis test method has no bias because the valuefor weight loss is defined solely in terms of this test method.10. Keywords10.1 solventless varnish; varnish; weight loss4Supporting data
23、 are available from ASTM Headquarters. Request RR: D-9-1014.TABLE 1 Standard Deviation and Weight LossHours at TemperatureWeight Loss, % Standard DeviationExposure Temperatures, C180 200 220 180 200 22024 0.119 0.331 0.618 0.028 0.048 0.02948 0.150 0.420 0.772 0.047 0.056 0.05672 0.170 0.475 0.849 0
24、.054 0.074 0.11096 0.190 0.525 0.977 0.060 0.076 0.103168 0.229 0.734 1.34 0.049 0.102 0.194D3377042ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that dete
25、rmination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or
26、 withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel tha
27、t your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D3377043
