1、Designation:D 2471 99Standard Test Method forGel Time and Peak Exothermic Temperature of ReactingThermosetting Resins1This standard is issued under the fixed designation D 2471;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year
2、 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.Scope*1.1 This test method covers the determination of the timefrom the initial mixing of the reactants of a thermosettingplast
3、ic composition to the time when solidification com-mences,under conditions approximating the conditions of use.This test method also provides a means for measuring themaximum temperature reached by a reacting thermosettingplastic composition,as well as the time from initial mixing tothe time when th
4、is peak exothermic temperature is reached.This test method is limited to reacting mixtures exhibiting geltimes greater than 5 min.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefo
5、re,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in nonconformancewith this test method.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
6、 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.4 This test method applies to adhesives,caulks,sealants,encapsulating and potting compounds,and similar materials,asdescribed in Table 1.NOTE1There is no similar or equivalen
7、t ISO standard.2.Referenced Documents2.1 ASTM Standards:D 883 Terminology Relating to Plastics2E 1 Specification for ASTM Thermometers33.Termonology3.1 Definitions:3.1.1 GeneralDefinitions of plastics terms used in thistest method are in accordance with Terminology D 883.4.Significance and Use4.1 Si
8、nce the gel time and the peak exothermic temperatureof a reacting thermosetting plastic composition vary with thevolume of material mixed at one time,it is essential that thevolume be specified in any determination.By selection of anappropriate volume,gel time and peak exothermic data may beobtained
9、 in sufficiently precise and reproducible form orapplication evaluation,quality control,and material character-ization of a thermosetting plastic composition.For mostmeaningful results,the cross sectional area of the materialbeing examined,as well as other conditions of testing,shouldapproximate as
10、closely as possible the conditions of use of thematerial.4.2 This test method is operator-dependent since it is simpleto perform.It is of value for determining conditions required toproduce an end product.5.Apparatus5.1 Sample Containers,to contain a volume of reactingthermosetting plastic in a cros
11、s sectional area representative ofthe conditions of application of the material.Suggested con-tainers are the following:5.1.1 Aluminum Foil Dish,approximately 7 cm(2.75 in.)indiameter and 1.4 cm(0.56 in.)deep.5.1.2 Paint Can,open-top,14-pt,approximately 6.00 cm(2.375 in.)in diameter by 5.00 cm(2 in.
12、)deep.5.1.3 Paint Can,open-top,1-pt,approximately 8.2 cm(3.25in.)in diameter by 9.5 cm(3.75 in.)deep.5.2 Wooden ProbeApplicator sticks approximately 0.24cm(0.09 in.)in diameter by 15.2 cm(6.00 in.)long have beenfound satisfactory.5.3 Nonconducting Surface,such as dry wood or corrugatedcasing.5.4 Tem
13、perature Measuring Devices:5.4.1 Any temperature recorder or indicator utilizing ex-pendable thermocouples and accurate to approximately 61%of scale is adequate for all but the most precise characterizingtests.NOTE2Previous versions of this test method have contained aparagraph detailing the possibl
14、e use of a thermometer for temperaturedetermination.Use of a thermometer is no longer recommended due topotential hazard of breakage as well as loss of the thermometer due toimbedment in the curing mass.1This test method is under the jurisdiction ofASTM Committee D-20 on Plasticsand is the direct re
15、sponsibility of Subcommittee D20.16 on Thermosetting Materi-als.Current edition approved Nov.10,1999.Published February 2000.Originallypublished as D 2471 66 T.Last previous edition D 2471 94.2Annual Book of ASTM Standards,Vol 08.01.3Annual Book of ASTM Standards,Vol 14.03.1*A Summary of Changes sec
16、tion appears at the end of this standard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.5.5 Temperature-Controlled Bath,capable of holding thetemperature within 60.1C.5.6 Stop Watch.6.Conditioning6.1 Place all components in suitable containers in thetemperature-controlled bath at the test temperature for at least4 h prior to being tested,or for however much longer time isneeded for all parts of the sample to reach the test temperature