1、Designation: D 6093 97 (Reapproved 2003)Standard Test Method forPercent Volume Nonvolatile Matter in Clear or PigmentedCoatings Using a Helium Gas Pycnometer1This standard is issued under the fixed designation D 6093; the number immediately following the designation indicates the year oforiginal ado
2、ption or, in the case of 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.1. Scope1.1 This test method covers the determination of the percentvolume nonvola
3、tile matter of a variety of clear and pigmentedcoatings. The approach used should provide faster and moreaccurate results than the use of the liquid displacementtechnique in Test Method D 2697, particularly for coatings thatare difficult to wet or that contain voids, cracks or other defects.The impr
4、ovement in accuracy stems from the superior abilityof helium gas under pressure to penetrate very small pores andsurface irregularities in dried films. This provides a moreaccurate determination of void volumes than can be obtainedvia liquid displacement.1.2 The technique will provide results under
5、the followingconstraints:1.2.1 The stability of the helium gas pycnometer is greaterthan 60.005 cm31.2.2 Test specimen weights are greater than 1 g.1.3 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are forinformation only.1.4 This standard d
6、oes 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 determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM St
7、andards:D 1475 Test Method for Density of Paint, Varnish, Lacquerand Related Products2D 2369 Test Method for Volatile Content of Coatings2D 2697 Test Method for Volume Nonvolatile Matter inClear or Pigmented Coatings2D 3960 Practice for Determining Volatile Organic Com-pound (VOC) Content of Paints
8、and Related Coatings2D 4708 Practice for Preparation of Uniform Free Films ofOrganic Coatings2E 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial Chemicals32.2 Other Documents:2.2.1 Directions for obtaining appropriate instructionmanuals on the use, car
9、e, and operation of the instrumentsand equipment are listed in Section 5, (Apparatus).3. Summary of Test Method3.1 This procedure measures the volume of nonvolatilematerial in a dried or baked coating film. A helium gaspycnometer is used to determine the volume occupied by a filmby measuring the red
10、uction of gas capacity in the pycnometersample chamber caused by the presence of the test specimen.(The actual measurement is accomplished with a pressuretransducer that measures the difference in pressure between theempty sample compartment and when loaded. The volumeoccupied by the coating sample
11、is then calculated from theIdeal Gas Law.) The weight of the specimen is also measuredand the two values are used to calculate the dry film density.3.2 The percent volume nonvolatile content of a coating iscalculated using the dry film density, liquid coating density,and the weight percent nonvolati
12、le content of the coating.4. Significance and Use4.1 This test method measures the volume of dry coatingobtainable from a given volume of liquid coating. This value isuseful for calculating the volatile organic content (VOC) of acoating and could be used to estimate the coverage (square feetof surfa
13、ce covered at a specified dry film thickness per unitvolume) obtainable with different coating products.NOTE 1In Practice D 3960 paragraph 10.3.1, the equation for calcu-lating the VOC content using the percent volume nonvolatile is given.Prior to this method a satisfactory procedure for measuring p
14、ercentvolume nonvolatile did not exist (see Note 11 in Practice D 3960).NOTE 2Since the actual coverage of a coating includes the voidvolume and the porosity of the film, the coverage value calculated fromthis method will be inaccurate by that amount, that is, the actual coveragewill be greater. The
15、 higher the pigment to binder ratio (P/B) of a coatingor the higher content of void containing material (latices, hollow beads,etc.) or both, the greater will be the deviation of the coverage calculation(This is also true to a lesser degree with Test Method D 2697).1This test method is under the jur
16、isdiction of ASTM CommitteeD01 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 March 10, 2003. Published May 2003. Originallyapproved in 1997 as D 6093 97.2Ann
17、ual Book of ASTM Standards, Vol 06.01.3Annual Book of ASTM Standards, Vol 15.05.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2 For various reasons the volume nonvolatile value ob-tained for a coating is often not equal to that p
18、redicted fromsimple linear addition of the weights and volumes of the rawmaterials in a formulation. One reason is that the volumeoccupied by a solution of resin in solvent may be the same,greater, or less than the total volume of the separate ingredi-ents. Such contraction or expansion of resin sol
19、utions isgoverned by a number of factors, one of which is the extent anddirection of spread between solubility parameters of the resinand solvent.4.3 The spatial configuration of the pigment particles andthe degree to which the pigment particles are filled with thebinder also affect the volume of a
20、dry coating film. Above thecritical pigment volume concentration, the apparent volume ofthe dry film is significantly greater than theoretical due to theincrease in unfilled voids between pigment particles. The useof volume nonvolatile matter values in such instances shouldbe carefully considered as
21、 the increased volume is largely dueto air trapped in these voids.4.4 For thin films, the issue of critical pigment volumeeffects is usually not a concern. With high poly(vinyl chloride)(PVC) films, however, liquid displacement of air voids takesplace with difficulty even under high pressures. Heliu
22、m solvesthis problem since, as a gas, it readily penetrates and displacesair, water, and volatile solvents even at low pressures. Purgingthe gas pycnometer flushes these materials from the film.5. Apparatus and Reagents5.1 Gas Pycnometer, equipped with a suitably sized cup.NOTE 3The data from the ro
23、und robin was obtained using a 5mLcupinstrument.45.2 Panels, steel or aluminum, 4 in. by 12 in. (102 mm by305 mm)5.3 Sheeting5, approximately 1.5mils (38-m) thick.5.4 Doctor Blades, 5 to 8 mils (127 to 203 m), appropriateto give 1.0 to 1.8 mils (25 to 46 m) dry film thickness).A3-in.(76-mm) wide, mu
24、ltiple clearance applicator is recommended.5.5 Standard Spray Equipment, capable of obtaining auniform film of 1.0 to 1.8 mil (25 to 46 m) dry film thicknessafter baking.5.6 Forced Draft Oven, capable of maintaining 110 6 5C.5.7 Single Edge Razor Blades or Scalpels ,5.8 Anti-Static Instrument.65.9 A
25、nalytical Balance, capable of weighing to 6 0.0001 g.5.10 A Paper/Thin Film Cutter, equipped with a rollingblade, available from most office supply centers.5.11 Polyethylene Gloves and Plastic Tweezers.6. Procedure6.1 Determine the wet coating density (pounds per gallon)in accordance with Test Metho
26、d D 1475.6.2 Determine the weight percent nonvolatile content of theliquid sample in accordance with Test Method D 2369.6.3 Wrap 4 by 12-in. panels (102 by 305-mm), (two persample) with sheeting5and tape the sheeting to the back of thepanels with masking tape. Do not overlap the sheeting on thebacks
27、 of the panels.NOTE 4The objective of this procedure is to obtain the coating free ofsubstrate. Other collection methods, such as scraping the coating fromglass plates or using release paper instead of sheeting5are acceptable. Seealso Practice D 4708 for other film preparation techniques.6.4 Place t
28、he wrapped panels on a panel rack and bake at160C, for 10 to 15 min. Baking will tighten the sheeting5andremove any wrinkles. After baking, allow panels to cool atroom temperature for at least 15 min.6.5 Prepare a thin, uniform, bubble-free film on the wrappedpanels either by spraying or with a draw
29、down blade, to obtaina dry film thickness of 1.0 to 1.8 mils (25 to 46 m). Thinnerfilms of 1.0 to 1.2 mils (25 to 31 m) have fewer potentialproblems with entrapped solvents.6.6 Bake the coated panels for 60 min at 110C in a forceddraft oven, then cool at room temperature for 20 to 30 min.6.7 Cut a s
30、lit across the top or bottom, about12 in. from theedge of the film. Separate a small portion of the film from thesheeting5with a scalpel or razor blade. Work a thin narrowspatula blade (about 4-12 in.-long (115mm) under the sepa-rated portion of the file then remove the film by working thespatula bl
31、ade between the film and substrate along and acrosseach side and end of the panel.6.8 Place the film on a piece of sheeting5or plain paper thathas been treated with the anti-static device. Treat the film withthe device in accordance with the manufacturers instructions.NOTE 5Using metal lab benches h
32、elps reduce static problems.6.9 Cut the film into strips, approximately14 by34 in. (6 by19 mm).NOTE 6Alternatively, if the film does not cut well or crumbles, thefilm may be loosely packed into the cup.6.10 Weigh the dried, empty cup and record.6.11 Place the film strips vertically into a sample cup
33、 untilthere is between 1.0 to 2.0 g of film in the 5-mL cup (If adifferent size cup is used, use a proportional amount of filmsample). Use the anti-static device as often as necessary. Thefilm strips should not be protruding from the cup.6.12 Weigh the sample strips and cup to verify there is atleas
34、t 1.0 g of the test specimen. Samples should be run induplicate.6.13 Conduct the experiment in accordance with the GasPycnometer Instruction Manual.6.14 Take at least five consecutive readings, in accordancewith instrument instructions. Variation in readings should be4The sole source of supply of th
35、e 5mL cup, Model 1305 known to thecommittee at this time is the Micromeritics Instrument Corp., One MicromeriticsDrive, Norcross, GA 300931877. If you are aware of alternative suppliers, pleaseprovide this information to ASTM International Headquarters. Your comments willreceive careful consideratio
36、n at a meeting of the responsible technical committee,1which you may attend.5The sole source of sheeting, Tedlart, PC105M3, known to the committee at thistime is the Dupont Company. If you are aware of alternative suppliers, pleaseprovide this information to ASTM International Headquarters. Your com
37、ments willreceive careful consideration at a meeting of the responsible technical committee,1which you may attend.6The sole source of supply of the anti-static instrument, Zerostat 3, known to thecommittee at this time is the Aldrich Chemical Co., Inc., (address). If you are awareof alternative supp
38、liers, please provide this information to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.D 6093 97 (2003)2random. A consistent volume increase indicates loss of trappedsolvent and results shoul
39、d be considered suspect. Refer to theinstrument instruction manual.6.15 Weigh the cup after finishing the instrument readings.6.16 Subtract the weight of the empty cup to obtain the filmweight.7. Calculation7.1 Calculate the dry film density, Df, from the pycnometervolume displacement (6.14) and fil
40、m weight (6.15) as follows:Df 5Film weight g!Volume displacement mL!(1)NOTE 7If the film density of duplicate runs differs by more than 0.05g/mL, the test should be repeated.7.2 Calculate dry film specific gravity, Sgf, as follows:Sgf 5Dfg/mL!0.9971 g/mL!(2)where 0.9971 = Density of distilled water
41、at 25C in g/mL.7.3 Calculate the dry film weight per gallon, Wgf,asfollows:Wgf 5 Sgf 3 8.312 lb./gal! (3)where 8.312 = weight of 1 gal of distilled water at 24C(lb./gal).7.4 Calculate percent volume solids nonvolatile content(VNV, %) as follows:VNV,%5weight % nonvolatiles 3 weight per gal liquid sam
42、ple!Wgf(4)NOTE 8If the wet sample density is determined by a device directlyreading out in g/L, the following equation can be used which generatesidentical VNV, % results as follows:VNV,%5weight percent NV 3 wet coating density g/mL!dry film density g/mL!(5)7.5 Example calculation:Df = 1.452 g/mLWei
43、ght percent nonvolatiles = 61.3 %Gallon weight (liquid sample) = 9.55 lb/galSgf = 1.452 g/mL 0.997 g/mL = 1.456Wgf = 1.456 3 8.312 lb /gal = 12.102 lb/galVNV, % = 61.3 % 3 9.55/12.102 = 48.4 %8. Precision and Bias8.1 Precision (In accordance with Practice E 180). In aninter laboratory study of this
44、test method five laboratoriesanalyzed in duplicate on two days, three coatings (one solvent-based and two water-reducible) with nonvolatile contentsranging from 27 to 48 volume percent. The pooled within-laboratory coefficient of variation was 1.16 % with 14 df andthe pooled between laboratories coe
45、fficient of variation 2.46 %with 11 df. Based on these coefficients of variation, thefollowing criteria should be used for judging the acceptabilityof results at the 95 % confidence level:8.1.1 RepeatabilityTwo results, each the mean of dupli-cate determinations, obtained by the same operator on dif
46、ferentdays should be considered suspect if they differ by more than3.5 % relative.8.1.2 ReproducibilityTwo results, each the mean of dupli-cate determinations, obtained by operators in different labora-tories should be considered suspect if they differ by more than7.67 % relative.8.2 BiasNo general
47、statement of bias can be made be-cause no reference material is available.9. Keywords9.1 coatings; helium gas pycnometer; paint film density,coverage; percent volume nonvolatile matter; VOC, volatileorganic compound contentASTM International takes no position respecting the validity of any patent ri
48、ghts asserted 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 an
49、y time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive 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 add
