1、Designation: D5327 97 (Reapproved 2013)Standard Practice forEvaluating and Comparing Transfer Efficiency of SprayApplied Coatings Under General Laboratory Conditions1This standard is issued under the fixed designation D5327; the number immediately following the designation indicates the year oforigi
2、nal adoption 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 practice covers the evaluation and comparison ofthe transfe
3、r efficiency of spray-applied coatings under generallaboratory conditions. Transfer efficiency is the ratio of paintsolids deposited to the total paint solids used during theapplication process, expressed as a percent. This practice canbe used to study the effect on transfer efficiency of changingop
4、erating variables and paint formulations. Key variables thatneed to be controlled are listed in 8.13.NOTE 1It is important that all process or formulation parameters,except that which is intentionally being changed, be kept consistent fromtest to test. If not done, the results of the study are to be
5、 questioned.1.2 The reproducibility of this practice is highly dependenton the degree of control of the parameters listed in Section 8 ofthe practice.1.3 LimitationsThis laboratory practice indicates only thedirection of the effect of operating variables and liquid paintformulations on transfer effi
6、ciency under conditions of thelaboratory test: the magnitude of the effect can be determinedonly with specific plant experience. In fact, the nature of thecritical parameters that affect transfer efficiency makes clearthat it is not possible to extrapolate laboratory results.NOTE 2The laboratory pra
7、ctice outlined involves general laboratoryspray equipment and procedures and is derived from Test Method D5009.This practice and Test Method D5009 are both derived from a study andreport of transfer efficiency measurements conducted for the U.S. Envi-ronmental Protection Agency. For laboratories tha
8、t have access to aconveyor and mass flow measurement equipment, a suitable, potentiallymore reproducible, tested method is defined in Test Method D5009.1.4 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
9、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. For specific hazardstatements see Sec
10、tion 7, Note 8 and Note 9.2. Referenced Documents2.1 ASTM Standards:2D1200 Test Method for Viscosity by Ford Viscosity CupD2369 Test Method for Volatile Content of CoatingsD3925 Practice for Sampling Liquid Paints and RelatedPigmented CoatingsD5009 Test Method for Evaluating and Comparing TransferEf
11、ficiency of Spray Applied Coatings Under LaboratoryConditions2.2 Other Standards:NFPA 33 Spray Application Using Flammable and Combus-tible Materials3NFPA 86 Standard for Ovens and Furnaces33. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 fluid mass flow rate, nthe mass flow ra
12、te of paint ingrams per minute during the test.3.1.2 mass of foil, nthe weight of each target foil in gramsbefore being painted.3.1.3 mass of foil plus paint solids, nthe weight of eachtarget foil in grams after being painted and baked.3.1.4 mass of paint solids, nthe difference in the mass ofthe fo
13、il before painting and the mass of the foil after paintingand baking. The sum of the mass of the foil plus paint solidsless the sum of the mass of the foil.3.1.5 transfer effciency, nthe ratio of the mass of the paintsolids deposited on the foil to the mass of the paint solidssprayed during the test
14、, expressed as a percent.3.1.6 weight percent solids, nthe solids content as percentof the total weight of a sample of the paint used during the test.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct responsibil
15、ity ofSubcommittee D01.55 on Factory Applied Coatings on Preformed Products.Current edition approved June 1, 2013. Published July 2013. Originally approvedin 1992. Last previous edition approved in 2007 as D5327 97 (2007). DOI:10.1520/D5327-97R13.2For referenced ASTM standards, visit the ASTM websit
16、e, 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.3Available from National Fire Protection Association (NFPA), 1 BatterymarchPark, Quincy, MA 02169-7471, http:/www.
17、nfpa.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.6.1 DiscussionWeight percent solids are determinedas specified in 8.4.2.4. Summary of Practice4.1 Metal panels covered with preweighed aluminum foilare coated in a spray boo
18、th. The coated foils are baked toremove volatile matter. The transfer efficiency is calculated ona weight percent basis using the solids content, quantity ofpaint sprayed, and the amount of solids on the coated alumi-num foil.5. Significance and Use5.1 Subject to the limitations listed in 1.3, this
19、practice canbe used as a research tool to optimize spray equipment andpaint formulations, as well as to study the relative effect ontransfer efficiency of changing operating variables, sprayapplication equipment, type of coatings, etc.6. Apparatus6.1 Laboratory Scale, accurate to 60.001 g.6.2 Platfo
20、rm Scale, accurate to 60.01 g.6.3 Targets, should consist of a minimum of three steelpanels, two scavengers and a target panel. If more than onetarget panel is used, a scavenger panel is to be used at the startand end of the test panel set. The steel panels are 15.2 by0.15875 cm wide (6 by 0.0625 in
21、.) with 0.635 cm (0.25 in.)radius corners. The length of the panel should be sufficient thata minimum of 30.4 cm (12 in.) above and below the spraypattern is achieved.NOTE 3It is essential to effectively capture the entire height of thespray pattern.NOTE 4Other panel sizes similar to those in the en
22、d use can be used.Differences in the part shape will influence the transfer efficiency.NOTE 5Results of this test may not be extrapolated to different spraybooths, part geometries, etc.6.4 Aluminum Foil, medium temper or equivalent,0.0037-cm (1.5-mil) thick. The aluminum foil should bepreheated at t
23、he conditions specified in the cure schedulerecommended by the paint manufacturer.6.5 Back-Draw Water-Wash Spray Booth, or equivalent. Thebooth should be capable of developing and maintaining up to36.58 m/min (120 ft/min) air velocity in the middle at the planeof the target. If a filter booth is use
24、d, filters should be changedas frequently as necessary to maintain uniform air velocity.6.6 Forced Draft Curing Oven, if required, of sufficient sizefor curing targets, capable of achieving and maintaining thecure temperature specified by the paint supplier. All ovensshould conform to NFPA 86.6.7 Cu
25、ring Rack.6.8 Stopwatch.6.9 Air Velocity Measurement Equipment.6.10 Humidity and Temperature Measurement Equipment.6.11 Compressed Air Supply.6.12 Spray Gun.NOTE 6The spray gun can be attached to a spray machine or handheld. Needless to say, operator variation with a hand held spray gun canmask the
26、effect of changes in the variable being studied.7. Hazards7.1 For specific hazard information and guidance, consultthe suppliers Material Safety Data Sheet (MSDS) for thematerials used.8. Procedure8.1 Set up the paint supply equipment to the spray apparatusin accordance with the manufacturers instru
27、ctions.8.1.1 Ground all electrically conductive objects in the sprayarea, except those objects required by the process to be at highvoltage in accordance with Chapter 9.11 of NFPA 33.8.2 Agitate the test paint in a closed container at least 30min before paint samples are taken.8.3 Using an airtight
28、container, take a paint grab samplefrom the paint pot in accordance with Practice D3925.8.4 Determine and record the following from the paintsample:8.4.1 Paint viscosity in accordance with Test MethodD1200,8.4.2 Weight Percent SolidsThe preferred method is TestMethod D2369. If the baking temperature
29、 in Test MethodD2369 is considered inadequate for complete cure, use themanufacturers recommended cure schedule. Make sure thatthe cure schedule used is agreed upon and recorded, and8.4.3 Electrical resistivity for samples being applied elec-trostatically.8.5 Cut the aluminum foil to dimensions of 5
30、8 by 5 cm (15by approximately 2 in.) longer than the length of the targetpanel.8.6 Number each precut foil strip, before weighing, using apermanent marking pen.8.7 Weigh each test foil strip and record the uncoatedweight and the foil number.8.8 Attach the preweighed, labeled test foil to the targets
31、using the technique shown in Fig. 1.8.9 Mount the foil covered targets on a panel or targetholder, with the foil seam on each target facing away from thespray gun. Set panel spacing as desired.8.9.1 If electrostatic equipment is being used, the resistanceshall be less than 1 by 106 between the targe
32、t and earthground, in accordance with Chapter 9.8 of NFPA 33.8.10 Adjust the following equipment operating parameters,as appropriate, to the values desired for testing:8.10.1 Paint fluid pressure at spray gun, kPa (psi),8.10.2 Atomizing air pressure at spray gun, kPa (psi),8.10.3 Rotating atomizer h
33、ead speed (revolutions per min-ute) with and without paint fluid flow,8.10.4 Operating voltage if electrostatic equipment is used,kV,8.10.5 Ambient air temperature (C),8.10.6 Paint fluid temperature (C),8.10.7 Booth air velocity, feet per minute (meters perminute),D5327 97 (2013)28.10.8 Relative hum
34、idity (percent),8.10.9 Spray machine variables or spray gun procedureswhen using a hand held spray gun,NOTE 7The spray gun can be attached to a spray machine or handheld. If hand held, variations in technique can effect reproducibility of thetransfer efficiency study and may override comparisons mad
35、e.8.10.10 Set the following variables where applicable (seeNote 8):8.10.10.1 Spray gun to target distance, cm (in.),8.10.10.2 Travel speed, centimetres per minute (inches perminute),8.10.10.3 Number of coats,8.10.10.4 Number of passes per coat, and8.10.10.5 Flash between coats, seconds.NOTE 8Precaut
36、ion: If electrostatic equipment is being used, thegun-to-target distance shall be at least twice the sparking distance inaccordance with Chapter 9.7 NFPA 33, where applicable.8.10.11 Set the cure time and temperature in accordancewith the manufacturers instructions.8.11 For electrostatic spray equip
37、ment, measure the operat-ing voltage, and adjust it according to the manufacturersinstructions.8.12 Turn on the spray booth. Turn on paint spray equip-ment. Maintain uniform paint flow during the test. Turn offspray equipment.8.13 Weigh the paint before and after the test.8.13.1 If the weight differ
38、ence measurement approach is notappropriate, use the following technique: just after turning onthe spray equipment, spray the unatomized paint into apreweighed plastic container for a minimum of 30 s.NOTE 9Precaution: Turn off all high voltage to electrostatic sprayguns to prevent personal injury.8.
39、13.2 Immediately weigh the container with paint, calcu-late the flow rate, and record the result. Before turning off thespray machine, repeat this procedure. Average the two resultsto obtain the average flow rate for the test.NOTE 10The use of a gallon plastic bottle with the top cut off toconvenien
40、tly fit around the front of the gun is recommended. A largeplastic beaker covered with plastic wrap with a hole punched in the centerof the plastic wrap may also be used. Turn off all air sources to the spraygun before using this procedure to prevent paint splatter out of thecontainer.8.14 Record th
41、e following data:8.14.1 Application Equipment:8.14.1.1 Paint fluid pressure at the spray gun, psi (kPa),8.14.1.2 Atomizing air pressure at spray gun, psi (kPa),8.14.1.3 Rotating atomizer head speed (revolutions perminute) with and without paint fluid flow,8.14.1.4 Spray machine settings,8.14.1.5 Ope
42、rating voltage at the electrode tip if electro-static equipment is used, kV,NOTE 11If a hand held spray gun is used, record the gun-to-paneldistance, number of coats, and the flash time between coats.8.14.1.6 Panel spacing, and8.14.1.7 Spray time.8.14.2 Spray Booth Variables:8.14.2.1 Ambient tempera
43、ture (C),8.14.2.2 Paint fluid temperature (C),8.14.2.3 Booth air velocity, feet per minute (meters perminute),NOTE 12Variations in booth air velocity can affect transfer efficiencyresults.8.14.2.4 Relative humidity (percent), and8.14.2.5 Mass of paint used for painting the targets, grams(pounds).NOT
44、E 13The mass of paint used may be determined by measuring thedifference in weight of the paint before and after the sprayout or bymultiplying the paint flow rate determined in 8.13.2 by the length of timethat the spray equipment is on.8.14.3 Operator name and date.8.15 After the paint flow is topped
45、, carefully remove thepainted targets from the panel holder to ensure that no paint islost.8.16 For products that are baked, hang the coated targets onoven racks so all painted surfaces are exposed for uniformdrying. Flash per the manufacturers recommendations, insertthe racks into the oven and bake
46、 using the manufacturersrecommended cure schedule. For products that are not baked,follow the manufacturers recommended cure schedule.8.17 Where appropriate, remove the targets from the ovenand let cool.NOTE 1Scale: Not To Scale. For y see 6.3 for dimensions.FIG. 1 Foil Attachment TechniqueD5327 97
47、(2013)38.18 Remove the foil from each target, weigh and record thecoated weight, the foil number, the dry film thickness at thecenter of the spray pattern, and the percent vertical filmcoverage. If the desired dry film thickness and the percentvertical film coverage is not achieved, repeat the proce
48、durelisted in 8.1-8.17.8.19 The mass of the paint solids deposited is the differencebetween the weight of the foil after painting and baking, andthe total weight of the foil before painting.9. Calculation9.1 Calculate the transfer efficiency using the followingequation:T 5 100 P/W 3 A! (1)where:T =
49、transfer efficiency, %P = mass of paint solids deposited, as specified in 8.19,W = weight percent solids expressed as a decimal as speci-fied in 8.4.2, andA = mass of paint applied, as specified in 8.13, 8.13.1,or8.13.2.10. Report10.1 Report the following information:10.1.1 Transfer efficiency results,10.1.2 Type of spray equipment,10.1.3 Type of paint applied,10.1.4 Paint application conditions as listed in 8.13, and10.1.5 Conditions of test other than those specified in theprocedure section of this practice.11. Keywords11.1 general laborato
