1、Designation: D6191 97 (Reapproved 2014)Standard Test Method forMeasurement of Evolved Formaldehyde from WaterReducible Air-Dry Coatings1This standard is issued under the fixed designation D6191; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f 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 may be used to measure the amount offormaldehyde evolved from air-dry water r
3、educible coatingsutilizing latices, resin emulsions, or water reducible alkyds.The results may be used to define the “free” formaldehydeevolved from a sample under controlled laboratory conditions.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its us
4、e. 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.2. Referenced Documents2.1 ASTM Standards:2D2194 Test Method for Concentration of FormaldehydeSolutions3. Summary of T
5、est Method3.1 A sample of water reducible coating is placed on thewalls of a test tube with a drawdown rod and purged withnitrogen. The evolved formaldehyde is collected in deionizedwater with tandem impingers and measured colorimetricallyusing acetylacetone at 412 nm.4. Significance and Use4.1 This
6、 test method measures the amount of formaldehydethat is released from a coating under laboratory conditions. Theamount of formaldehyde available for release from a coatingmay vary depending on composition, and may decrease as thesample ages.4.2 This test method may be used for typical air dried pain
7、tswhere water is the major volatile material. The useful range isestimated to be from 10 ppm to 1000 ppm formaldehyde in thesample.4.3 Significant amounts of other volatile aldehydes, such asacetaldehyde, are reported to cause an interference with thedetermination of formaldehyde. This limitation is
8、 not expectedto cause a problem for most common water reducible coatings.4.4 Samples containing organic solvents as the major vola-tile component have not been evaluated and are not expected tobe compatible with this test method.5. Apparatus5.1 Formaldehyde Collection Apparatus, assembled using aflo
9、wmeter to control the nitrogen flow at ; 1.0 L/min, a 25 by200 mm outside diameter long glass test tube, and two 30-mLmidget impingers. Connections are made with glass tubesthrough a No. 4 two-hole rubber stopper and clear flexibletubing (see Fig. 1).5.2 Drawdown Bar, stainless steel No. 22 wire-wou
10、nd6.4-mm rod.5.3 Glass Sample Bottles, (;2 oz), capable of holding30-mL solution.5.4 Spectrophotometer, capable of measuring the absor-bance of solutions at 412 nm with a minimum sample light pathof 10 mm.6. Reagents6.1 Acetylacetone SolutionDissolve 150 6 0.1 g ammo-nium acetate in ;600 mL deionize
11、d water in a 1-L volumetricflask. Add 3.0-mL glacial acetic acid and 2.0-mL acetylacetone(2,4 pentanedione) and dilute to volume.6.2 Formaldehyde SolutionUse 37 % in methanol/water,commercial stock standard solution. If a commercially cali-brated 37 % standard solution is not being used, the concen-
12、tration of formaldehyde may determined in accordance withTest Method D2194. Then, the actual concentrations of theworking calibrations standards are to be calculated using themeasured value. (WarningFormaldehyde, acetylacetone,and the other reagents used in this test method are toxic or1This test me
13、thod is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved July 1, 2014. Published July 2014. Originally approvedin 1
14、997. Last previous edition approved in 2008 as D6191 97 (2008)1. DOI:10.1520/D6191-97R14.2For 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 Summ
15、ary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1hazardous. Exposure to these materials should be minimized.Consult the suppliers Material Safety Data Sheet for specifichazard information.)6.3 Formaldehyde C
16、alibration StandardsPrepare a 100-ppm stock solution by diluting 25 uL of the 37 % formaldehydesolution to 100 mL with deionized water. Dilute this interme-diate stock solution to prepare at least 5 calibration standards.Pipeting 0.5, 3, 5, 7 and 10 mL aliquots of the stock solutioninto 100-mL volum
17、etric flasks and diluting with deionizedwater will prepare calibration standards of 0.5, 3, 5, 7 and 10ppm formaldehyde.7. Calibration7.1 Prepare a series of at least 5 standards (6.3) plus a blankby adding 5 mL of the formaldehyde calibration standards or 5mL deionized water into test tubes. Proces
18、s the standard alongwith the samples as described in 8.5 to 8.6.7.2 Construct a calibration curve by plotting the absorbanceof the calibration standards versus concentration of formalde-hyde (ppm). Prepare a new calibration curve with every batchof samples being analyzed.8. Procedure8.1 Assemble the
19、 collection apparatus as shown in Fig. 1.The ;1.0 L/min. flow rate should be determined by timing theflow with a bubble tube. If the impingers are not accuratelygraduated, pipet 15-mL deionized water into the impingertubes and mark the level for future reference.8.2 Place about 1 to 1.5 g of the liq
20、uid sample into a taredtest tube and evenly spread the sample on the walls with a No.22 drawdown rod. The bottom couple of inches of the test tubewill not be coated and the top ;12 in. of the tube should bewiped free of coating with a paper towel to avoid having painton the stopper. Quickly weigh th
21、e coated test tube and recordthe weight of the liquid sample.8.3 Without delay, connect the test tube to the apparatuscontaining 15-mL deionized water in each impinger and purgewith nitrogen at ;1.0 L/min for 2 h.8.4 With the nitrogen flowing, remove the impinger tubefrom the No. 2 impinger. If the
22、sampling liquid is less than theoriginal 15 mL volume, restore the volume to 15 mL whilerinsing the impinger tube with deionized water. Disconnect theNo. 1 impinger in the series and rinse the impinger tube withdeionized water in order to restore the volume to 15 mL. Pourthe No. 1 impinger solution,
23、 which should contain most of theformaldehyde, into a ;2-oz. bottle. Use the No. 2 impingersolution to wash the No. 1 impinger tube and mix the combinedsolutions in the sealed bottle.8.5 Pipet 5 mL of the impinger solution (or a dilutedsolution) into a ;20-mL glass test tube and add 5 mL of theacety
24、lacetone solution. Mix the prepared test solutions and heatthe test tubes in a 40 6 0.5C water bath for 30 min.8.6 Remove the test tubes from the water bath and let standfor 30 min to cool. Measure the absorbance at 412 nm with aspectrophotometer using a 1-cm cell and deionized water as thereference
25、.8.7 From the calibration curve, determine the concentrationof the combined impinger solution. If the concentration of thetest solution is greater that the highest standard, make appro-priate dilutions of the impinger solution and repeat 8.5 to 8.6with freshly prepared standards. Some analysts may p
26、refer toprepare dilutions initially rather than repeat the standardpreparation process.9. Calculation9.1 Calculate the amount of formaldehyde that is evolvedfrom the sample as follows:ppm Formaldehyde 5C 330 3DW(1)where:C = concentration from calibration curve (8.7),30 = volume (mL) of water in the
27、impingers,D = dilution factor if diluted, andW = sample weight, g.10. Report10.1 Report the concentration of evolved formaldehydefrom the sample as parts per million rounded to two significantdigits.11. Precision and Bias11.1 RepeatabilityTo be determined.11.2 ReproducibilityTo be determined.11.3 Bi
28、asThe bias can not be determined since no validstable reference material is available.12. Keywords12.1 air-dry water reducible coatings; evolved formalde-hydeFIG. 1 Formaldehyde Collection ApparatusD6191 97 (2014)2ASTM International takes no position respecting the validity of any patent rights asse
29、rted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination 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
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31、ve careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that 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 Inter
32、national, 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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 97 (2014)3
