1、Designation: D7232 06 (Reapproved 2012)Standard Test Method forRapid Determination of the Nonvolatile Content of Coatingsby Loss in Weight1This standard is issued under the fixed designation D7232; the number immediately following the designation indicates the year oforiginal adoption or, in the cas
2、e 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 This test method is used to obtain rapid determination ofthe weight percent nonvolatile (so
3、lids) content via instrumentalloss in weight technology. It is not meant as a replacement forTest Method D2369.1.2 This test method is principally intended for qualitycontrol labs and manufacturing environments where previouslycharacterized materials will be tested repeatedly for differentbatches or
4、 lots.1.3 This 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 informa
5、tiononly.1.5 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 establish appro-priate safety and health practices and to determine theapplicability of regulatory limitations prior to use.NOTE
6、1There is no similar or equivalent ISO standard.2. Referenced Documents2.1 ASTM Standards:2D16 Terminology for Paint, Related Coatings, Materials, andApplicationsD2369 Test Method for Volatile Content of CoatingsE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of I
7、ndustrial and Spe-cialty Chemicals (Withdrawn 2009)33. Terminology3.1 Definitions:3.1.1 The definitions used in this test method are in accor-dance with Terminology D16.3.1.2 nonvolatile content, nthe coating material that re-mains in the pan at the conclusion of the test.3.2 Definitions of Terms Sp
8、ecific to This Standard:3.2.1 flip and 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
9、 pan, the filter paper is “flipped” over 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 vol
10、atiles release from the specimen and avoidingincomplete volatiles removal due to “skinning over” of thesample material.3.2.2 lift, nthe result of convection currents created duringthe heating of the specimen that raises the sample pan off of itssupport and falsely indicates a weight loss.3.2.2.1 Dis
11、cussionThis effect is compensated for 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 DiscussionT
12、he specimen weight is determinedusing 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 use
13、d to minimize error due to rapidchange of the specimen weight after addition to a heatedsample pan.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, andApplications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of
14、 Paints and Paint Materials.Current edition approved June 1, 2012. Published July 2012. Originally approvedin 2006. Last previous edition approved in 2006 as D7232 06. DOI: 10.1520/D7232-06R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at se
15、rviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
16、 PA 19428-2959. United States14. 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 temperature to vaporize thevolatile
17、s. 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 weightpercent nonvolatiles. Both the analyzers balance and heaterare calibrated with NIST-traceable standards to achieve precisea
18、nd 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 be used for repeat testing ofthat material.5. Significance and Use5.1 This
19、 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 results asTest Method D2369, which takes over one hour to run, the timeand
20、effort expended on determining the optimal conditions fortesting a coating with this instrumental method is valuablewhen numerous measurements are going to be made ondifferent lots or batches of the same material. Also, theautomation of the measurement and the calculations shouldlead to fewer mistak
21、es 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 of compensating for lift causedby convection currents created during testing.
22、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, withsmooth, uncoated, oil-free surface.6.3 Round glass-fiber filter paper, Grade 111.
23、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-pressure sources to controlled delivery pressuresthat are appropriate for the appa
24、ratus.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 the heatershall be calibrated using an NIST-traceable temperature cali-bration
25、 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 %. Otherprocedures for materials with known theoretical water contentare accepta
26、ble 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 prepare analyzer foranalysis as described in 9.1 using a flat pan without filter p
27、aper.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 to begintest. Specimen size shall be determined by analyzer manufac-turer.8.
28、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 dihydrate(or other standard material as specified by the instrumentmanufactu
29、rer). 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 the heating chamber per theinstrument manufacturers instructions.9.1.3 Turn the
30、 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 Program the analyzer with the desired test parameters,or select the suggested
31、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 pan with glass filter paper,rough side up, on the pan support and close the li
32、d. Allow theanalyzer to equilibrate at the desired idle temperature.9.2.3 Ensure sample material is thoroughly mixed beforedrawing specimen into syringe.4If using syringe tare technique(see 3.2.3), proceed to step 9.2.4. If using flip and squish (see3.2.1) technique, proceed to step 9.2.5.4The speci
33、men size will depend on the test conditions specified for a particularanalyzer. See Table A1.1 in Annex A1 for suggested sample size for specified testconditions.D7232 06 (2012)29.2.4 If syringe tare is used:9.2.4.1 Initiate the test on the analyzer and follow theprompts for placing the specimen on
34、the sample pan.9.2.4.2 Draw sample material into the syringe, then wipe thesyringe to ensure that no sample material 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
35、 to the filter paper on the panby dispensing material from syringe onto the filter paper in aspiral pattern, then 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 theinitial and final we
36、ight of the syringe and cap is the actualspecimen weight for the test, which is calculated as follows:WA5 WI2 WF(1)where:WA= actual weight of specimen to be entered into analyzer,WI= initial weight of loaded syringe and cap, andWF= final weight of syringe and cap after dispensingspecimen.9.2.5 If th
37、e 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 paper on the panby dispensing material from syringe onto the filter paper in
38、 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 onto pan support and close lid tobegin test. Do not allow tweezers to come in
39、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 obtainthe final result.9.2.7 Record the result as displayed in percent nonvolatil
40、es.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 Method D2369.9.3.1 Program the analyzer according to the conditionslisted in An
41、nex 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 identical in its parametersexcept for the temperature, which is progressively increa
42、sed5C 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 corresponds tothe lowest temperature in the linked series.9.3.3 Record the result f
43、or each test in the linked series asthe ratio of the ending weight to the beginning weight inpercent by calculating as follows:RN5 EN/BN! 3100# (2)where:RN= ratio of ending weight to beginning weight in percentfor a given linked test N (to be plotted againsttemperature),EN= ending weight for linked
44、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 tempera-ture range from points 1 to 3.NOTE 5The ratio of the ending weight to beg
45、inning 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 approach 100 %(the ratio of ending weight to beginning approaches 1) andbecome con
46、stant. 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 volatiles fromthe specimen material during routine analysis, and that thetemperature
47、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 necessarily beobserved. The optimum temperature may be determined as described instep 9.3.4.2 before a tem
48、perature 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 D2369 onthe same material.9.3.6 Once correlation has been optimized, record param
49、-eters for use on repeat tests of the same material.9.4 Sample Analysis for Repeat Tests:FIG. 1 Optimum Test Temperature SelectionD7232 06 (2012)39.4.1 Following steps 9.2 through 9.2.7, and using opti-mized test conditions as determined in 9.3, determine nonvola-tile content for 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:N 5 NA1NB!/2 (3)where:N = mean
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