1、Designation: D 7232 06Standard Test Method forRapid Determination of the Nonvolatile Content of Coatingsby Loss in Weight1This standard is issued under the fixed designation D 7232; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he 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 This test method is used to obtain rapid determination ofthe weight percent nonvolatile (solids) content v
3、ia instrumentalloss in weight technology. It is not meant as a replacement forTest Method D 2369.1.2 This test method is principally intended for qualitycontrol labs and manufacturing environments where previouslycharacterized materials will be tested repeatedly for differentbatches or lots.1.3 This
4、 test method can be used for waterborne andsolventborne resins, intermediates and finished paint products.This test method may not be applicable to all types of coatings.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.5 T
5、his 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 establish appro-priate safety and health practices and to determine theapplicability of regulatory limitations prior to use.NOTE 1There is no s
6、imilar or equivalent ISO standard.2. Referenced Documents2.1 ASTM Standards:2D16 Terminology for Paint, Related Coatings, Materials,and ApplicationsD 2369 Test Method for Volatile Content of CoatingsE 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial an
7、d Spe-cialty Chemicals3. Terminology3.1 DefinitionsThe definitions used in this test method arein accordance with Terminology D16.3.1.1 nonvolatile content, nthe coating material that re-mains in the pan at the conclusion of the test.3.2 Definitions of Terms Specific to This Standard:3.2.1 flip and
8、squish, na testing technique that may beused when the expected nonvolatile content is greater than40 %, or when the sample is highly viscous and does notabsorb well into the filter paper.3.2.1.1 DiscussionThe specimen is applied to the filterpaper on the sample pan, the filter paper is “flipped” ove
9、r andthe specimen is then “squished” between the filter paper andthe sample pan in order to more uniformly distribute thespecimen. In addition, use of this technique forces the glassfibers of the filter paper into the specimen, helping to createpathways for volatiles release from the specimen and av
10、oidingincomplete volatiles removal due to “skinning over” of thesample material.3.2.2 lift, nthe result of convection currents created dur-ing the heating of the specimen that raises the sample pan offof its support and falsely indicates a weight loss.3.2.2.1 DiscussionThis effect is compensated for
11、 by theuse of an algorithm that is applied to the digital data.3.2.3 syringe tare, na testing technique that may be usedwhen the expected nonvolatile content is less than 40 %, orwhen the sample is highly volatile and tends to evaporaterapidly.3.2.3.1 DiscussionThe specimen weight is determinedusing
12、 an external balance by calculating the difference betweenthe syringe weight before (initial weight) and after (finalweight) the specimen is applied to the pan. This differencebetween initial and final weight is the actual weight ofspecimen (see 10.2), and is used to minimize error due to rapidchang
13、e of the specimen weight after addition to a heatedsample pan.4. Summary of Test Method4.1 The specimen is spread onto a sample pan that issupported on a balance in a heating chamber that has beenpreheated and equilibrated to the specified idle temperature. Itis then heated to the specified test tem
14、perature to vaporize thevolatiles. The analysis is completed when the indicated rate ofweight loss falls below a rate specified in the test conditions.The total weight loss is calculated and reported as weight1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coati
15、ngs, Materials, andApplications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved June 1, 2006. Published June 2006.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service a
16、t serviceastm.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.percent nonvolatiles. Both the analyzers balance
17、and heaterare calibrated with NIST-traceable standards to achieve preciseand accurate results.4.2 Through adjustment of the analyzers parameter set-tings, a set of optimal conditions is developed for each materialtype to measure the percent nonvolatiles. These optimalconditions are recorded and may
18、be used for repeat testing ofthat material.5. Significance and Use5.1 This test method is intended for use as a rapid qualitycontrol, acceptance, and assessment test. Results are obtainedin five to fifteen minutes on most materials. Since the instru-ment parameters are adjusted to produce the same r
19、esults asTest Method D 2369, which takes over one hour to run, thetime and effort expended on determining the optimal condi-tions for testing a coating with this instrumental method isvaluable when numerous measurements are going to be madeon different lots or batches of the same material. Also, the
20、automation of the measurement and the calculations shouldlead to fewer mistakes being made by less-trained operators.6. Apparatus6.1 Analyzer, containing:6.1.1 An oven capable of heating the sample to at least225C.6.1.2 A balance capable of measuring to the nearest 0.0001g.6.1.3 An electronic means
21、of compensating for lift causedby convection currents created during testing.6.1.4 A processor that is capable of converting the loss ofweight to digital data.6.1.5 Digital display for presenting the digital data asweight percent nonvolatiles.6.2 Flat disposable pan, of aluminum alloy 3003, withsmoo
22、th, uncoated, oil-free surface.6.3 Round glass-fiber filter paper, Grade 111.6.4 Syringe, 3 cc plastic slip-tip without needle but withcap, capable of dispensing specimen onto pan.6.5 Nitrogen compressed gas (N2) dry and oil-free.6.6 Compressed gas regulator(s), as needed to supply N2from high-press
23、ure sources to controlled delivery pressuresthat are appropriate for the apparatus.7. Reagents7.1 Sodium Tartrate DihydrateACS certified reagentgrade.8. Calibration and Standardization8.1 To maintain the integrity of the test results, the balanceshall be calibrated using NIST-traceable weights and t
24、he heatershall be calibrated using an NIST-traceable temperature cali-bration interface per the analyzer manufacturers guidelines.8.2 The calibration may be verified using sodium tartratedihydrate, which has a theoretical water content of 15.66 %,with an acceptable result range of 15.61 to 15.71 %.
25、Otherprocedures for materials with known theoretical water contentare acceptable for verification as specified by the analyzermanufacturer.8.3 Prepare the analyzer for use, select the preprogrammedinstrument parameters for sodium tartrate dihydrate (or otherstandard material if applicable) and prepa
26、re analyzer foranalysis as described in 9.1 using a flat pan without filter paper.8.4 Initiate the test on the analyzer and follow the promptsfor placing the specimen on the sample pan.8.5 Spread a thin, even layer of sodium tartrate dihydrate ofappropriate specimen size onto the pan, then close lid
27、 to begintest. Specimen size shall be determined by analyzer manufac-turer.8.6 If results are not within the acceptable range, firstperform a temperature calibration, temperature calibrationverification, and then a balance calibration to ensure properanalyzer performance. Retest with sodium tartrate
28、 dihydrate(or other standard material as specified by the instrumentmanufacturer). If results still are not within the acceptablerange, contact analyzer manufacturer.9. Procedure9.1 Preparing Analyzer for Sample Analysis:9.1.1 Place the analyzer on a flat, level surface.9.1.2 Establish N2purge to th
29、e heating chamber per theinstrument manufacturers instructions.9.1.3 Turn the analyzer on and allow equilibration at therecommended idle temperature for balance calibration for 30min.9.1.4 Perform balance calibration per the analyzer manufac-turers instructions.9.2 Performing Sample Analysis:9.2.1 P
30、rogram the analyzer with the desired test parameters,or select the suggested test conditions from Annex A1. See9.3.1 for determining the optimal conditions for testing acoating. See 9.3.5 for repeat testing of a coating usingpreviously determined optimal conditions.9.2.2 Place a clean, flat sample p
31、an with glass filter paper,rough side up, on the pan support and close the lid. Allow theanalyzer to equilibrate at the desired idle temperature.9.2.3 Ensure sample material is thoroughly mixed beforedrawing specimen into syringe.3If using syringe tare technique(see 3.2.3), proceed to step 9.2.4. If
32、 using flip and squish (see3.2.1) technique, proceed to step 9.2.5.9.2.4 If syringe tare is used:9.2.4.1 Initiate the test on the analyzer and follow theprompts for placing the specimen on the sample pan.9.2.4.2 Draw sample material into the syringe, then wipe thesyringe to ensure that no sample mat
33、erial remains on theexterior, then cap the syringe tip.9.2.4.3 Weigh the loaded syringe with cap on a balance andrecord the result. This is the initial weight.9.2.4.4 Quickly apply specimen to the filter paper on the panby dispensing material from syringe onto the filter paper in aspiral pattern, th
34、en recap the syringe and close lid to begin test.9.2.4.5 Immediately weigh the syringe and cap and recordthe result. This is the final weight. The difference between the3The specimen size will depend on the test conditions specified for a particularanalyzer. See Table Table A1.1 in Annex A1 for sugg
35、ested sample size for specifiedtest conditions.D7232062initial and final weight of the syringe and cap is the actualspecimen weight for the test, which is calculated as follows:WA5 WI WF(1)where:WA= actual weight of specimen to be entered into ana-lyzer,WI= initial weight of loaded syringe and cap,
36、andWF= final weight of syringe and cap after dispensingspecimen.9.2.5 If the flip and squish is used:9.2.5.1 Draw sample material into the syringe.9.2.5.2 Initiate the test on the analyzer and follow theprompts for placing the specimen on the sample pan.9.2.5.3 Quickly apply specimen to the filter p
37、aper on the panby dispensing material from syringe onto the filter paper in aspiral pattern.9.2.5.4 In rapid succession, remove the sample pan from thesupport, flip over the filter paper with tweezers and gentlysquish the specimen between the filter paper and the samplepan. Place sample pan back ont
38、o pan support and close lid tobegin test. Do not allow tweezers to come in contact with thespecimen on the filter paper.9.2.6 At the end of the test, allow the analyzer to cool andremove the sample pan. If syringe tare was used, input theactual specimen weight at the completion of the test to obtain
39、the final result.9.2.7 Record the result as displayed in percent nonvolatiles.9.3 Determination of Optimal Test Conditions:NOTE 2When determining the optimal test conditions for a material,it is useful to have a calibrated forced-draft oven available and test thematerial in accordance with Test Meth
40、od D 2369.9.3.1 Program the analyzer according to the conditionslisted in Annex A1.3.9.3.2 To determine the optimum test temperature for acoating, run one series of tests on a single coating specimenthat consists of several consecutive programs that have beenlinked together. Each program is identica
41、l in its parametersexcept for the temperature, which is progressively increased5C on each successive program.NOTE 3For each test in the series, ensure that the ending weight ofone test is used for the beginning weight of the subsequent test.NOTE 4Ensure that the program selected to run first corresp
42、onds tothe lowest temperature in the linked series.9.3.3 Record the result for each test in the linked series asthe ratio of the ending weight to the beginning weight inpercent by calculating as follows:RN5 EN/ BN! 3 100 (2)Where:RN= ratio of ending weight to beginning weight in percentfor a given l
43、inked test N (to be plotted againsttemperature),EN= ending weight for linked test N, andBN= beginning weight for linked test N.9.3.4 After the tests are completed, plot each linked testresult, RN, versus temperature to make a curve as in Fig. 1.9.3.4.1 Most of the volatiles are vaporized in the temp
44、era-ture range from points 1 to 3.NOTE 5The ratio of the ending weight to beginning weight increaseswith temperature for the specimen during the first few tests in linked seriesas the higher temperatures evaporate more and more of the volatilecontent.9.3.4.2 Between points 3 and 5, the results appro
45、ach 100 %(the ratio of ending weight to beginning approaches 1) andbecome constant. Choose a temperature in this range as theoptimum test temperature for that specimen material. A tem-perature in this range, where the RNvalue first becomesconstant, ensures that there will be a total loss of volatile
46、s fromthe specimen material during routine analysis, and that thetemperature is not excessively high.9.3.4.3 Beyond point 5, the results may begin to decrease.This trend is likely caused by decomposition of the sample.NOTE 6The region in the graph beyond point 5 may not necessarilybe observed. The o
47、ptimum temperature may be determined as described instep 9.3.4.2 before a temperature sufficient to degrade the specimen isreached.9.3.5 After the optimal test temperature has been deter-mined, adjust other appropriate parameters as needed tooptimize correlation with results from an analysis by D 23
48、69on the same material.9.3.6 Once correlation has been optimized, record param-eters for use on repeat tests of the same material.9.4 Sample Analysis for Repeat Tests:9.4.1 Following steps 9.2 through 9.2.7, and using opti-mized test conditions as determined in 9.3, determine nonvola-tile content fo
49、r each coating by performing the analysis induplicate.10. Calculation10.1 Result is reported in weight percent nonvolatiles tothree decimal places so no further calculations are necessary.10.2 Calculate mean, N, percent nonvolatile content asfollows:FIG. 1 Optimum Test Temperature SelectionD7232063N 5 NA1 NB!/ 2 (3)where:N = mean percent nonvolatile content,NA= first weight percent nonvolatile determination, andNB= duplicate weight percent nonvolatile determination.11. Report11.1 Report the following information:11.1.1 Complete identification of the sample
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