1、Designation: D6093 97 (Reapproved 2011)Standard Test Method forPercent Volume Nonvolatile Matter in Clear or PigmentedCoatings Using a Helium Gas Pycnometer1This standard is issued under the fixed designation D6093; the number immediately following the designation indicates the year oforiginal adopt
2、ion or, in the case 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 covers the determination of the percentvolume nonvolatil
3、e 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 D2697, particularly for coatings thatare difficult to wet or that contain voids, cracks or other defects.The improvem
4、ent 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 the
5、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 standard. The values given in parentheses are mathematicalconversions to SI units that are pr
6、ovided for information onlyand are not considered standard.1.4 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 determine the applica-bi
7、lity of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1475 Test Method For Density of Liquid Coatings, Inks,and Related ProductsD2369 Test Method for Volatile Content of CoatingsD2697 Test Method for Volume Nonvolatile Matter in Clearor Pigmented CoatingsD3960 Pract
8、ice for Determining Volatile Organic Com-pound (VOC) Content of Paints and Related CoatingsD4708 Practice for Preparation of Uniform Free Films ofOrganic CoatingsE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals32.2 Other Docum
9、ents:2.2.1 Directions for obtaining appropriate instructionmanuals on the use, care, 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 ga
10、spycnometer is used to determine the volume occupied by a filmby measuring the reduction 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 thee
11、mpty sample compartment and when loaded. The volumeoccupied by the coating sample 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 u
12、sing the dry film density, liquid coating density,and the weight percent nonvolatile 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
13、 (VOC) of acoating and could be used to estimate the coverage (square feetof surface covered at a specified dry film thickness per unitvolume) obtainable with different coating products.NOTE 1In Practice D3960 paragraph 10.3.1, the equation for calcu-lating the VOC content using the percent volume n
14、onvolatile is given.Prior to this method a satisfactory procedure for measuring percentvolume nonvolatile did not exist (see Note 11 in Practice D3960).1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct respon
15、sibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved June 1, 2011. Published June 2011. Originallyapproved in 1997. Last previous edition approved in 2003 as D6093 97 (2003).DOI: 10.1520/D6093-97R11.2For referenced ASTM standards, visit the ASTM
16、website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright AS
17、TM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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 actua
18、l coveragewill be greater. The 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 D2697).4.2 F
19、or various reasons the volume nonvolatile value ob-tained for a coating is often not equal to that predicted 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
20、 less than the total volume of the separate ingredi-ents. Such contraction or expansion of resin solutions 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
21、 andthe degree to which the pigment particles are filled with thebinder also affect the volume of a 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 part
22、icles. The useof volume nonvolatile matter values in such instances shouldbe carefully considered as 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, h
23、owever, liquid displacement of air voids takesplace with difficulty even under high pressures. Helium 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. App
24、aratus and Reagents5.1 Gas Pycnometer, equipped with a suitably sized cup.NOTE 3The data from the round robin was obtained using a 5-mL cupinstrument.45.2 Panels, steel or aluminum, 4 in. by 12 in. (102 mm by305 mm).5.3 Sheeting5, approximately 1.5-mils (38-m) thick.5.4 Doctor Blades, 5 to 8 mils (1
25、27 to 203 m), appropriateto give 1.0 to 1.8 mils (25 to 46 m) dry film thickness).A3-in.(76-mm) wide, multiple 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, cap
26、able of maintaining 110 6 5C.5.7 Single Edge Razor Blades or Scalpels,5.8 Anti-Static Instrument.65.9 Analytical Balance, capable of weighing to 60.0001 g.5.10 A Paper/Thin Film Cutter, equipped with a rollingblade, available from most office supply centers.5.11 Polyethylene Gloves and Plastic Tweez
27、ers.6. Procedure6.1 Determine the wet coating density (pounds per gallon)in accordance with Test Method D1475.6.2 Determine the weight percent nonvolatile content of theliquid sample in accordance with Test Method D2369.6.3 Wrap 4 by 12-in. panels (102 by 305-mm), (two persample) with sheeting5and t
28、ape the sheeting to the back of thepanels with masking tape. Do not overlap the sheeting on thebacks 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 o
29、f sheeting5are acceptable. Seealso Practice D4708 for other film preparation techniques.6.4 Place the 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
30、.5 Prepare a thin, uniform, bubble-free film on the wrappedpanels either by spraying or with a drawdown 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 f
31、or 60 min at 110C in a forceddraft oven, then cool at room temperature for 20 to 30 min.6.7 Cut a slit 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.-
32、long (115-mm) under the sepa-rated portion of the file then remove the film by working thespatula blade 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 f
33、ilm withthe device in accordance with the manufacturers instructions.NOTE 5Using metal lab benches helps 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 cu
34、p.6.10 Weigh the dried, empty cup and record.6.11 Place the film strips vertically into a sample cup 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
35、 should not be protruding from the cup.4The sole source of supply of the 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 Int
36、ernational Headquarters. Your comments willreceive careful consideration 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, plea
37、seprovide this information to ASTM International Headquarters. Your comments 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 Ald
38、rich Chemical Co., Inc., (address). If you are awareof alternative suppliers, please provide this information to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.D6093 97 (2011)26.12 Weigh the sa
39、mple strips and cup to verify there is atleast 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 readi
40、ngs should berandom. A consistent volume increase indicates loss of trappedsolvent and results should 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. Calc
41、ulation7.1 Calculate the dry film density, Df, from the pycnometervolume displacement (6.14) and film 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 spe
42、cific gravity, Sgf, as follows:Sgf 5Dfg/mL!0.9971 g/mL!(2)where 0.9971 = Density of distilled water 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 s
43、olids nonvolatile content(VNV, %) as follows:VNV,%5weight % nonvolatiles 3 weight per gal liquid sample!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 perce
44、nt NV 3 wet coating density g/mL!dry film density g/mL!(5)7.5 Example calculation:Df = 1.452 g/mLWeight 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. Preci
45、sion and Bias8.1 Precision (In accordance with Practice E180). In aninter laboratory study of this 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 with
46、in-laboratory coefficient of variation was 1.16 % with 14 df andthe pooled between laboratories coefficient 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 Repeata
47、bilityTwo results, each the mean of dupli-cate determinations, obtained by the same operator on differentdays 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
48、-tories should be considered suspect if they differ by more than7.67 % relative.8.2 BiasNo general 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, volatileor
49、ganic compound contentASTM International takes no position respecting the validity of any patent rights 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 any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments ar
