ASTM D3539-1987(2004) Standard Test Methods for Evaporation Rates of Volatile Liquids by Shell Thin-Film Evaporometer《壳式薄膜蒸发计测定挥发性液体蒸发速率的试验方法》.pdf

1、Designation: D 3539 87 (Reapproved 2004)Standard Test Methods forEvaporation Rates of Volatile Liquids by Shell Thin-FilmEvaporometer1This standard is issued under the fixed designation D 3539; the number immediately following the designation indicates the year oforiginal adoption or, in the case of

2、 revision, the 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 These test me

3、thods cover the determination of the rateof evaporation of volatile liquids of low viscosity using theShell thin-film evaporometer. These test methods have beenapplied to a wide range of volatile liquids, including paint,varnish, and lacquer solvents and thinners to various hydrocar-bons and to inse

4、cticide spray-base oils.1.2 The test methods for the determination of evaporationrate using the thin-film evaporometer are:SectionsTest Method A2,3Manual Recording 5-11Test Method BAutomatic Recording 12-171.3 These test methods are limited only by the viscosity ofthe volatile liquid which must be s

5、ufficiently low to permit thedispensing of an accurately measured specimen from a syringe.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.5 This standard does not purport to address all of thesafety concerns, if any, asso

6、ciated 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. Specific hazardstatements are given in 5.2 and 5.6.2. Referenced Documents2.1 ASTM Standards:4D 891

7、 Test Methods for Specific Gravity, Apparent, ofLiquid Industrial ChemicalsE 1 Specification for ASTM Liquid in Glass Thermometers3. Summary of Test Methods3.1 A known volume of liquid is spread on a known area offilter paper that is suspended from a sensitive balance in acabinet. Dried air or nitro

8、gen at 25C is passed through thecabinet at a known rate. The loss of weight of the filterpaper/liquid is determined and plotted against time.4. Significance and Use4.1 The rate of evaporation of volatile liquids from asolution or dispersion is important because it affects the rate ofdeposition of a

9、film and flow during deposition, and therebycontrols the structure and appearance of the film. In theformulation of paints and related products, solvents are chosenbased on the evaporation characteristics appropriate to theapplication technique and the curing temperature.1These test methods are unde

10、r the jurisdiction of ASTM Committee D01 onPaint and Related Coatings, Materials, and Applications and are the directresponsibility of Subcommittee D01.24 on Physical Properties of Liquid Paints andPaint Materials.Current edition approved July 1, 2004. Published July 2004. Originally approvedin 1976

11、. Last previous edition approved in 1996 as D 3539 76 (1996).2These test methods are essentially the same as the one developed by the NewYork Society for Paint Technology. The Precision section was added by ASTMSubcommittee D01.24 and is based upon the data of the New York Society for PaintTechnolog

12、y.3See “Comparative Evaporation Rates of Solvents: II,” New York Club,Technical Subcommittee No. 66, Offcial Digest, 28, No. 382, 1956, p. 1060.4For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards v

13、olume information, refer to the standards Document Summary page onthe ASTM website.FIG. 1 Details of the Thin-Film Evaporometer1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.TEST METHOD AEVAPORATION RATE USINGTHE MANUAL THIN-FILM EV

14、APOROMETER5. Apparatus5.1 Evaporometer, thin-film evaporometer5as shown inFig. 1 (see Annex A1).5.2 Constant-Temperature Cabinet for evaporometer.(WarningIn instances with the solvents and other volatilematerials normally tested using this apparatus and under theconditions specified in this test met

15、hod, the concentration ofsolvent or other flammable material being exhausted into thelaboratory atmosphere will be significantly below any concen-tration that could be hazardous, that is, a lower flammablelimit. However, it may be desirable to locate the instrument andcabinet in a laboratory exhaust

16、 hood if the routine handling ofcertain materials may present a hazard due to toxicity, extremevolatility, or flammability.)5.3 Interval Timer: Stopwatch or Electric TimerA timerthat gives an audible signal at 10 or 20-s intervals and thatgives a warning signal approximately 3 s before the end of th

17、einterval is preferred.5.4 Filter Paper DiskFast, open-textured filter paper, 90mm in diameter, with a circle approximately 60 mm indiameter (and concentric with the edge) lightly drawn on thepaper with a pencil.5.5 SyringeA 1.00-mL hypodermic syringe equipped witha 225-mm needle of 1.3-mm outside d

18、iameter stainless steeltubing.6Due to manufacturing variations, the syringe should becalibrated before use.5.6 Dehumidification EquipmentA suggested setup isgiven in a schematic diagram, Fig. 2. (WarningUse of thisdehumidification apparatus requires the safety practices rela-tive to the handling, us

19、e, and disposal of hazardous acids andcaustics be observed. When handling these materials, protec-tive eye or face shields, or both, and protective clothing arerecommended.)5.7 Hygrometer (or other humidity-sensing device), capableof indicating low humidities.5.8 Thermometers, of suitable accuracy s

20、uch as ASTMBomb Calorimeter thermometer 56C having a range from 19 to35C, subdivisions 0.02C or Thermometer 56F (66 to 95Fwith 0.05F subdivisions), and conforming to the requirementsof Specification E 1.6. Preparation of Evaporometer6.1 Place the filter paper disk on the wire support, threadingthe h

21、ook through a small hole in the center of the paper. Attachthe hook to the steel spring below the sighting disk and allowthe paper and the paper support to hang therefrom.6.2 Close the evaporometer and cabinet doors and allow thetemperature in both chambers and the humidity to equilibrate atthe foll

22、owing test conditions:Cabinet and evaporation temperature: 25 6 0.25C (77 6 0.5F)Evaporometer humidity: 0 to 5 % relative humidityApproximately 2 h are required for the humidity to drop toless than 5 %.6.3 Adjust the air flow to 21 L/min (center of ball floatopposite correct mark on the rotometer sc

23、ale).7. Conditioning7.1 Bring the sample or a portion of it to an equilibriumtemperature of 25 6 0.5C (77 6 1.0F) in a constant-temperature bath. Determine the specific gravity of the sampleat this temperature in accordance with Test Methods D 891.8. Procedure8.1 Record the position of the filter pa

24、per as indicated byalignment of the sighting disk with its mirror image. This is theno-load position.8.2 Raise the wire mesh bracket until the bottom of the disksupport rests lightly on it.8.3 Withdraw into the syringe 0.70 mL of the solvent whichis at 25 6 0.5C (77 6 1.0F). Make certain that all ai

25、r bubblesare expelled from the syringe and the needle before applicationof the specimen to the filter paper.5The manual Shell thin-film evaporometer is no longer available.6Syringe: Becton, Dickinson and Co., No. 1YT available from Fisher ScientificCo. Needle: Special Syringe Needle Type LNR, 18-gag

26、e, 9-in. long blunt round end,no bevel available on special order from Becton, Dickinson and Co. through FisherScientific Co., 711 Forbes Ave., Pittsburgh, PA 15239.NOTE 1One-litre flasks should be used throughout.FIG. 2 Diagram of Dehumidification ApparatusD 3539 87 (2004)28.4 Insert the hypodermic

27、 needle into the small opening onthe right-hand side of the instrument and position the needle tipso that it almost touches the disk and is just over the line thatwas drawn.8.5 Start applying the solvent to the disk. As the first drophits the disk, start the timer. The solvent should be applied at a

28、uniform rate in 62 s and as evenly as possible along the drawnline. To ensure consistent specimen size, touch the tip of thehypodermic needle to the filter paper to dispense the last dropof solvent.8.6 Immediately lower the wire mesh bracket away from thedisk support. Obtain the first reading of the

29、 position of thesighting disk at 40 s and then every 20 s. Record the time andthe scale reading on the report form. A sample report form isshown in Annex A2.NOTE 1With very slow evaporating solvents, it is not necessary totake readings as often as every 20 s. The operator can determine a suitabletim

30、e interval after the first 200 s.8.7 Stop the timer when the sighting disk has returned to theoriginal unloaded position.NOTE 2The filter paper may be reused provided the solvent leaves noappreciable residue in evaporating.9. Calculation9.1 Calculate the evaporation rate as follows:ER 5CS3 100B 2 Z!

31、 (1)where:S = V 3 D and Z = N (S/C)ER = evaporation rate, wt %,C = spring constant, cm/g elongation,S = specimen weight,V = 0.70-mL aliquot volatile liquid at 25 6 0.5C (77 61.0F),D = density of volatile liquid at 25 6 0.5C (77 6 1.0F)(Taken as equivalent to specific gravity but withunits of mL/g)B

32、= scale reading taken during evaporation of aliquot,Z = zero percent evaporated, scale reading = N (S/C).andN = no-load scale reading (100 % evaporated reading).9.2 Plot the percent evaporated against elapsed time inseconds and draw a smooth curve through the points. From thecurve, determine at 10 w

33、eight % increments to 90 % and for 95and 100 % evaporation the time in seconds to the nearest valueas follows:Approximate ElapsedTime to 100 % Report to NearestEvaporated Point, s Indicated Value, sLess than 300 1300 to 600 5600 to 1800 101800 to 3600 303600 to 7200 60More than 7200 nearest 2 % of i

34、ndicated valueNOTE 3The curve drawn through the various points should passthrough zero or the origin. If it passes to the right of the origin, thedelivery time was in excess of 12 s or an aliquot larger than that specifiedwas delivered. If it passes to the left of the origin, then the aliquot wassma

35、ller than specified.10. Report10.1 Report the elapsed time in seconds at 10 weight %intervals through 90 % and for 95 and 100 % evaporation, andthe relative evaporation rate (n-butyl acetate = 1.0). Relativeevaporation rate is calculated from the 90 weight % evaporatedtimes for the test solvent and

36、for n-butyl acetate (99 % ester).11. Precision711.1 On the basis of an interlaboratory study of the testmethod in which operators in six laboratories determined the90 % evaporation point of six solvents covering a broad rangein evaporation rate, the between-laboratories coefficient ofvariation was f

37、ound to be 6.3 % relative at 24 df afterdiscarding two divergent values. On the basis of the resultsobtained by three laboratories on three of the solvents having90 % evaporated times of 200 to 600 s, the within-laboratorycoefficient of variation was found to be 0.83 % relative at 18 df.Based on the

38、se coefficients, the following criteria should beused for judging the acceptability of results at the 95 %confidence level:11.1.1 RepeatabilityFor solvents with 90 % evaporationtimes of 200 to 600 s, two results, each the mean of twodeterminations, obtained by the same operator on differentdays shou

39、ld be considered suspect if they differ by more than2.5 %.11.1.2 ReproducibilityTwo results, each the mean of twodeterminations, obtained by operators in different laboratoriesshould be considered suspect if they differ by more than18.2 %.TEST METHOD BEVAPORATION RATE USINGTHIN-FILM EVAPOROMETER, AU

40、TOMATICRECORDING12. Apparatus12.1 Evaporometer, automatic thin-film evaporometer,8asshown in Fig. 3.12.2 Filter Paper DiskSee 5.4.12.3 SyringeSee 5.5.12.4 Dehumidification EquipmentSee 5.6.12.5 Strip Chart RecorderAny strip chart recorder ca-pable of recording the output signal (0 to 15 mA) from the

41、electronic optical weight-sensing device. The recorder shouldprovide a range of chart speeds including 6.3 to 50 mm (14 to2 in.)/min. It is also desirable for the recorder to accommodate2 or more mA ranges in order to regulate the sensitivity ofmeasurement.7Supporting data are available from ASTM In

42、ternational Headquarters. RequestRR:D011003.8The automatic Shell thin-film evaporometer, Apparatus Catalog No. F1522 isavailable from the Falex Corporation, Inc., 2055 Comprehensive Drive, Aurora, IL60505.D 3539 87 (2004)313. Preparation of Evaporometer13.1 Place the filter paper disk on the wire fr

43、ame threadingthe hook through a small hole in the center of the paper. Attachthe wire frame to the support hook in the evaporometer.13.2 Close the evaporometer and cabinet doors and equili-brate both chambers as in 6.2.13.3 Adjust the air flow to 21 min/L.14. Conditioning of Sample14.1 See 7.1.15. P

44、rocedure15.1 When all components (including the filter paper inplace) are at equilibrium, adjust the recording pen to aprominent “zero” position near the edge of the chart on therecorder; then turn the switch for the chart motor to the OFFposition. This constitutes the “zero” load and time position

45、forthe test.NOTE 4The milliampere range and chart speed should be selected, ifpossible, so that the dimensions of the weight and time axes of the plottedcurve are approximately the same length.15.2 Measure 0.70 mL of test sample into the hypodermicsyringe (see 8.3).15.3 Open the small side door on t

46、he right-hand side of theinsulating cabinet and insert the hypodermic needle through therubber porthole until the needle tip almost touches the disk andis just over the penciled line.NOTE 5Care must be exercised to avoid depressing the plunger of thesyringe during this operation. Otherwise the solve

47、nt will be accidentallyand prematurely dispensed onto the paper before the strip chart recorderis started.15.4 When all is ready turn the strip chart motor switch tothe ON position and simultaneously start distribution of thespecimen onto the filter paper. The complete specimen shouldbe dispensed un

48、iformly in 106 2 s along the line. The recorderpen will “advance” immediately to an “apex” position equiva-lent to the total weight of the specimen, less that portion thatevaporated during the application period. The pen will gradu-ally return to its original position as the solvent evaporates andth

49、e chart advances. The evaporation is complete when therecording pen has returned to its original “no-load” position.NOTE 6It is common for the final portion of the curve to exhibit a“tailing-off.” This is due to artifacts of the method such as (1) hydrogenbonding of the last traces of solvent with the cellulose fibers of the filterpaper and (2) a gradual diminution of the area of the filter paper wet bysolvent (that is, in the final stage of evaporation, drying of the paperprogresses from the outer edge toward the center of the disk). Thu