1、Designation: D6762 02a (Reapproved 2017)Standard Test Method forDetermining the Hiding Power of Paint by Visual Evaluationof Spray Applied Coatings1This standard is issued under the fixed designation D6762; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n 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 provides for the quantitative visualdetermination of the film thi
3、ckness required to achieve fullhiding. This film thickness is considered to be the hiding powerof a test paint.1.2 This method applies only to spray applied coatings butits concepts are valid for other methods of application as well.1.3 The values stated in inch-pound units are to be regardedas stan
4、dard. The values given in parentheses are mathematicalconversions to SI units that are provided 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 st
5、andard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision
6、 on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D16 Terminology for Paint, Related Coatings, Materials, andApplicationsD609 Practice
7、for Preparation of Cold-Rolled Steel Panelsfor Testing Paint, Varnish, Conversion Coatings, andRelated Coating ProductsD1005 Test Method for Measurement of Dry-Film Thick-ness of Organic Coatings Using MicrometersD1186 Test Methods for Nondestructive Measurement ofDry Film Thickness of Nonmagnetic C
8、oatings Applied toa Ferrous Base (Withdrawn 2006)3D1400 Test Method for Nondestructive Measurement of DryFilm Thickness of Nonconductive Coatings Applied to aNonferrous Metal Base (Withdrawn 2006)3D1729 Practice for Visual Appraisal of Colors and ColorDifferences of Diffusely-Illuminated Opaque Mate
9、rialsD1730 Practices for Preparation of Aluminum andAluminum-Alloy Surfaces for PaintingD2805 Test Method for Hiding Power of Paints by Reflec-tometryE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 DefinitionsFor definitions of terms
10、used in this testmethod, refer to Terminology D16 and the Paint/CoatingsDictionary.44. Summary of Test Method4.1 The test paint is applied by means of spray applicationin a wedge-shaped film over a black and white, black and grayor red and gray pattern so that a thickness variation is obtained,which
11、 provides excess hiding at one end of the pattern andpartial hiding at the other end of the pattern.4.2 The dry film is examined under standard illumination toselect the point where the pattern just becomes obscured. Thethickness of the film at this point is designated the hidingpower of the paint.5
12、. Significance and Use5.1 This test method determines hiding power of a test paintby visual evaluation of a spray applied coating.NOTE 1Test Method D2805 describes an instrumental method fordetermining hiding power. The paint film is applied at a uniform thickness(for example with a doctor blade), t
13、he film thickness is measuredrigorously, and the opacity is determined photometrically. Hiding power is1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.26 on Optical Propert
14、ies.Current edition approved Dec. 1, 2017. Published December 2017. Originallyapproved in 2002. Last previous edition approved in 2009 as D6762 02a (2009).DOI: 10.1520/D6762-02AR17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.or
15、g. 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.4Published by the Federation of Societies for Coatings Technology, 492Norristown Rd., Blue Bell,
16、 PA 19422.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopmen
17、t of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1thereby determined with a high degree of precision.5.2 Test Method D6762 is less precise than Test MethodD2805, but is commonly used since it is more closely r
18、elatedto the application characteristics of the paint and is simpler inconcept and evaluation.6. Apparatus6.1 Test Surface, a smooth-surfaced paper chart, approxi-mately 2 by 11 in., with a test pattern having adjacent black andwhite, black and gray or red and gray areas and coated with asuitable va
19、rnish or lacquer so as to render the surface imper-vious to paint liquids.NOTE 2The red, gray, white and black areas should fall in thefollowing colorimetric range:CIE-Y % CAhARed 47 1018 2638Gray 2834White 8083Black 1 maxAValid for Illuminant D6510or C2, with 0/45 geometry.6.2 Illumination, a light
20、 source providing diffuse light ofreasonable intensity, preferably northern sky light or an ap-proximation of the same (see Practice D1729).6.3 Backer Panel, 4 by 12 in. steel or aluminum panel. Alarger panel may be used if desired.6.4 Film Thickness Measuring Device, a film thicknessmeasuring devic
21、e in accordance with Test Methods D1005,D1186, and D1400.6.5 Spray Equipment, either a hand spray gun or an auto-matic spray machine.6.6 Oven, capable of maintaining the bake schedule for theproduct being evaluated.6.7 Tape, masking or adhesive.7. Preparation of Wedge-shaped Paint Film (HandSpray)7.
22、1 Prepare the backer panel in accordance with PracticesD609 or D1730.7.2 Attach the desired test pattern to one side of the backerpanel with masking tape or adhesive tape.7.3 Reduce the material being tested to spray viscosity.7.4 Attach spray gun to a suitable compressed air supplyline and adjust a
23、ir pressure for consistent fan spray.7.5 Position the backer panel so that the long side is vertical.The panel should be placed so that the spray gun tip isapproximately 12 in. from the face of the panel.7.6 Prepare a wedge-shaped film. An example of a proce-dure for preparing a wedge-shaped film by
24、 means of handspray is shown in Appendix X1.NOTE 3The film thickness should vary from partial hiding at one endto excess hiding at the other end, but the total variation from one end tothe other should not exceed 50 m.7.7 Remove the panel and flash and bake per the recom-mended bake schedule.8. Prep
25、aration of Wedge-shaped Paint Film (AutomaticSpray Machine)8.1 Prepare the backer panel in accordance with PracticesD609 or D1730.8.2 Attach the desired test pattern to the one side of thebacker panel with masking tape or adhesive tape.8.3 Reduce the material being tested to spray viscosity.8.4 Posi
26、tion the backer panel on the panel holder so that thelong side is horizontal or vertical depending on the type ofspray machine being used.8.5 Prepare a wedge-shaped film. An example of a proce-dure for preparing a wedge-shaped film by means of anautomatic spray machine is shown in Appendix X2.NOTE 4
27、The film thickness should vary from partial hiding at one endto excess hiding at the other end, but the total variation from one end tothe other should not exceed 50 m.8.6 Remove the panel and flash and bake per the recom-mended bake schedule.9. Evaluation Procedure9.1 Remove the panel from the oven
28、 and cool to roomtemperature.9.2 Examine the test panel, as shown in Fig. 1, underillumination conditions as described in 6.2 at a viewing angleperpendicular to the surface of the panel, and select the pointwhere the test pattern is just barely or no longer visible. Thedry film thickness at this poi
29、nt is considered to be the hidingpower of the coating.NOTE 5The viewing angle may change depending on customerrequirements.9.3 Measure the film thickness at the point of hiding per TestMethods D1005, D1186,orD1400.FIG. 1 Test PanelD6762 02a (2017)210. Report10.1 Report the coating under evaluation,
30、with serial num-ber if applicable.10.2 Report the hiding power, as noted in 9.3, in m (mils).11. Precision and Bias511.1 Precision:11.1.1 An interlaboratory study of this test method wasconducted in which one operator in each of six laboratoriesmade two determinations each on six samples of paint. T
31、hesamples represented two paint samples at each of threedifferent levels of hiding power. The samples were analyzedstatistically in accordance with Practice E691. On the basis ofthe standard deviations shown in Table 1, the following criteriashould be used for judging the acceptability of results at
32、 the95 % confidence level:11.1.1.1 RepeatabilityTwo results obtained by the sameoperator should be considered suspect if they differ by morethan the maximum allowable differences shown in Table 1,Section A.11.1.1.2 ReproducibilityTwo results obtained by operatorsin different laboratories should be c
33、onsidered suspect if theydiffer by more than the maximum allowable differences shownin Table 1, Section B.11.2 No information can be presented on the bias of theprocedure in Test Method D6762 for measuring hiding powerbecause no acceptable reference standard is available.12. Keywords12.1 hiding powe
34、r; spray applied coating; visual evaluationAPPENDIXES(Nonmandatory Information)X1. PREPARATION OF WEDGE-SHAPED PAINT FILM BY HAND SPRAY (EXAMPLE)X1.1 Mount the panel vertically and spray the entire panelwith a uniform coat of the test material approximately 10 mthick.X1.2 Flash and then spray the lo
35、wer34 of the panel with anadditional coat of the test material approximately 10 m thick.X1.3 Flash and then progressively spray the remaininglower areas of the panel, for example, bottom12, bottom14,etc., until complete hiding is achieved near the center of thepanel.NOTE X1.1Allow sufficient flash t
36、ime, as experience dictates, toprevent sagging or flooding.NOTE X1.2The film thickness should vary from partial hiding at oneend to excess hiding at the other end, but the total variation from one endto the other should not exceed 50 m.X2. PREPARATION OF WEDGE-SHAPED PAINT FILM BY AUTOMATIC SPRAY MA
37、CHINE (EXAMPLE)X2.1 Spray a wedge-shaped film using an automatic spraymachine. The spray machine should be programmed to yieldthe following spray pattern:Portion 1 Portion 2 Portion 3 Portion 41 Pass 2 Passes 3 Passes 4 PassesX2.2 After spraying Portion 4, rotate the panel 180 andrepeat as shown bel
38、ow:4 Passes 3 Passes 2 Passes 1 PassTotal Total Total Total8 Passes 6 Passes 4 Passes 2 PassesNOTE X2.1Allow sufficient flash time, as experience dictates, toprevent sagging, flooding or popping.5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Rese
39、arch Report RR:D01-1126. ContactASTM CustomerService at serviceastm.org.TABLE 1 Precision of Hiding Power of Paint by Visual Evaluationof Spray Applied CoatingsHiding LevelmilsAveragemilsStandard DeviationmilsMaximum Allowable DifferenceMils (micrometers)A. Repeatability (single operator)0.60.8 0.7
40、0.09 0.25 (6.3)1.01.4 1.2 0.11 0.30 (7.6)1.62.2 2.0 0.07 0.21 (5.3)B. Reproducibility (between laboratories)0.6.08 0.7 0.16 0.45 (11.3)1.01.4 1.2 0.39 1.08 (7.6)1.62.2 2.0 0.48 1.33 (33.8)D6762 02a (2017)3ASTM International takes no position respecting the validity of any patent rights asserted in c
41、onnection 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 resp
42、onsible 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 carefu
43、l 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 International,
44、 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:/ 02a (2017)4
