1、Designation: D 5895 03 (Reapproved 2008)Standard Test Methods forEvaluating Drying or Curing During Film Formation ofOrganic Coatings Using Mechanical Recorders1This standard is issued under the fixed designation D 5895; the number immediately following the designation indicates the year oforiginal
2、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 These test methods describe the determination of severalstages and t
3、he rate of dry-film formation of organic coatingsusing straight line and circular mechanical drying-time record-ing devices. The use of mechanical recorders is valuable incomparing the drying behavior of coatings of the same generictype, allowing that one coating may form a gel or resist tearingat a
4、 faster rate than another.1.2 Drying time measured using the mechanical recordersmay differ from those found using conventional methods, suchas Test Method D 1640 or ISO 1517.1.3 The values stated in SI are to be regarded as thestandard. The values given in parentheses are provided forinformation on
5、ly.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-bility of regulatory limitations prior to use.2. Reference
6、d Documents2.1 ASTM Standards:2D 823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Related Products on Test PanelsD 1005 Test Method for Measurement of Dry-Film Thick-ness of Organic Coatings Using MicrometersD 1640 Test Methods for Drying, Curing, or Film Forma-tion of Or
7、ganic Coatings at Room TemperatureD 3924 Specification for Environment for Conditioning andTesting Paint, Varnish, Lacquer, and Related MaterialsD 3925 Practice for Sampling Liquid Paints and RelatedPigmented Coatings2.2 ISO Standard:ISO 1517 Drying Time Using Ballotini33. Terminology3.1 Description
8、s of Terms Specific to This Standard:3.1.1 dry-hard time, nthe dry-hard condition is reachedusing mechanical recorders when the drying and curing, orboth, reactions have proceeded sufficiently that the film is notdisplaced nor is any noticeable mark left by pinching the panelsbetween the thumb on th
9、e film and forefinger with a relativelystrong force.3.1.1.1 DiscussionIn these test methods, the dry-hardtime is reached where the stylus has risen out of the film andrides on the surface, leaving only a mark without disrupting thebody of the film (see Fig. 1 and Fig. 2).3.1.2 dry-through time, nthe
10、 dry-through condition isreached when the film has solidified so completely that a large,twisting force can be applied without distorting the film.3.1.2.1 DiscussionIn these test methods, the dry-throughtime is reached when the stylus no longer left any visible markon the film (see Fig. 1 and Fig. 2
11、).3.1.3 set-to-touch time, nThe set-to-touch condition isreached when the film has solidified sufficiently, by solventevaporation or chemical reaction, or both, that it not longerflows nor sticks to a finger that lightly touches it.3.1.3.1 DiscussionIn these test methods, the set-to-touchtime is rea
12、ched where a pear-shaped depression appears in thefilm when the film stops flowing over the path of the recordersstylus and leaves a track in the film revealing the glasssubstrate (see Fig. 1 and Fig. 2).3.1.4 tack-free time, nthe tack-free condition is reachedusing mechanical recorders when the fil
13、m surface has dried orcured (see set-to-touch time) so that the film does not adhere tovery light objects placed on it.3.1.4.1 DiscussionIn these test methods, the tack-freetime is reached where the continuous track in the film ceasesand the stylus starts to tear the film or leave a ragged/sharp-edg
14、ed grove as it first begins to climb over the film (see Fig. 1and Fig. 2).NOTE 1The above descriptions are typical for coatings that do not1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings, Materials, and Applications and are the directresponsibility o
15、f Subcommittee D01.23 on Physical Properties of Applied PaintFilms.Current edition approved June 1, 2008. Published June 2008. Originallyapproved in 1996. Last previous edition approved in 2003 as D 5895 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer
16、 Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM Internation
17、al, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.skin over during curing. Any coating which exhibits skinning, such as twopack epoxies or polyurethane coatings, will show a very different trackwhere the stylus tears the surface of the film, leaving diamond orki
18、te-shaped patterns.4. Summary of Test Methods4.1 In Test Method A (Straight Line Recorder), the coatingis applied to glass strips approximately 300 by 25 mm (12 by1 in.). The drying time recorder is immediately placed on thewet film and the stylus lowered onto the wet coating. The stylusmoves across
19、 the glass strip at a selected constant speed.4.2 In Test Method B (Circular Recorder), the coating isapplied to glass plates approximately 6 in. by 6 in. (150 by 150mm). The drying time recorder is immediately placed on thewet film and a stylus is moved in a 360 arc at a selectedconstant speed.5. S
20、ignificance and Use5.1 The drying times of a coating are significant in deter-mining when a freshly painted room, floor or stair may be putback in use or a coated article handled or packaged. Slowdrying may result in dirt pick-up or, on an exterior surface,moisture may cause a nonuniform appearance.
21、5.2 These test methods are used to determine the variousstages of drying or curing in the dry-film formation of organiccoatings using mechanical devices for the purpose of compar-ing types of coatings or ingredient changes, or both. Toevaluate the stages of drying in a quantitative manner, use ofins
22、trumentation under environmental controlled conditions isstrongly recommended. These devices also offer a method ofdetermining drying characteristics of coatings that can not beascertained within the standard 8-h work day.5.3 When evaluating drying characteristics of baking sys-tems, the circular dr
23、ying time devices offer a method todetermine quantitatively drying times of coatings at roomtemperature and elevated conditions. Maximum temperatureswould be limited by considerations such as the affect oftemperature on the motor lubrication or structural componentsof the device.5.4 The straight lin
24、e drying time devices offer a method todetermine quantitatively drying times of coatings tested simul-taneously using one recorder.5.5 This method is useful in comparing the behavior ofcoatings during drying of the same generic type. Determinationof actual drying times should be conducted following
25、proce-dures outlined in Test Method D 1640 or ISO 1517.6. Coatings and Recommend Film Thicknesses6.1 Whenever tests are to be performed on coatings notlisted in Table X1.1, there should be a prior agreement betweenthe purchaser and seller as to the substrate, film thickness,application method, and c
26、onditions for testing the specificcoating involved.6.2 Tests should be carried out at a practical viscosity underwhich the coating can be applied at the proper film thicknesswith resultant good flow and leveling properties.6.3 Films to be tested should have practical thicknessescommensurate with tho
27、se expected under actual usage for thetype under test.7. Test Conditions7.1 Air Dry Coatings, conduct all tests in a well ventilatedroom, free from direct drafts, dust, laboratory fumes, and underdiffused light. Make all measurements at a temperature of 23 62C and 50 6 5 % relative humidity in accor
28、dance withSpecification D 3924. For baking systems, conduct all tests ina forced draft oven at controlled temperatures within the limitsof the drying time device.7.2 Light ConditionsIllumination of air dry films duringthe entire drying test period should be about 270 lx (25 fc) fromnormal laboratory
29、 or sky sources, never from direct sunlight orother sources high in nonvisible radiant energy.8. Preparation of Test Specimens8.1 All test specimens shall be prepared and tested by oneoperator properly skilled in the methods to be used. ConductNOTE 1The above figure represents a typical track of a c
30、oating thatdoes not skin over during curing. Any coating which exhibits skinning,such as two pack epoxies or polyurethane coatings, will show a verydifferent track where the stylus tears the surface of the film, leavingdiamond or kite-shaped patterns.FIG. 1 Stages of Drying Using Straight Line Dryin
31、g TimeRecordersFIG. 2 Stages of Drying Using Circular Time Drying RecordersD 5895 03 (2008)2testing at least in duplicate. Sampling shall be conducted inaccordance with procedures outlined in Practice D 3925.8.2 Apply the test materials to clean glass panels or otherspecific substrates of suitable d
32、imensions agreed upon betweenthe purchaser and the seller.NOTE 2Ground-glass plates may be more suitable for certain types ofcoatings that have a tendency to crawl, such as low-viscosity drying oils.Suitable plates can be prepared by roughening the surface of polishedglass by grinding a paste of sil
33、icon carbide (grit 1-F) and water betweentwo glass plates.8.3 Cast the test films preferably with an appropriate filmapplicator for the recommended dry film thickness as indicatedin Table X1.1. When a suitable applicator is not available or ithas been agreed to apply the film in some other manner, t
34、hevarious conventional or automatic methods of spray, dip, flowand brush application may be used, provided dry film thick-nesses conform to the requirements in Table X1.1. See PracticeD 823 for a descriptions of the spray and dip methods ofapplication.8.4 Measure the dry film thickness of the test f
35、ilms with anappropriate film thickness gage.Amicrometer or dial indicator,as described in Test Methods D 1005, has been found suitablefor glass substrates.TEST METHOD ASTRAIGHT LINE DRYING TIME9. Apparatus9.1 Straight Line Drying Time Recorder, consists of mul-tiple styli 2 mm (0.08 in.) in diameter
36、 with rounded tips, beingdrawn over multiple parallel-coated glass panels typicallymeasuring 300 by 25 mm (12 by 1 in.). The stylus armgenerally comes with 5-g brass weights that may be added toapply greater pressure on the needles and thus record throughdrying. Other weights can be adapted as agree
37、d upon betweenpurchaser and seller. Speed can be varied to cover dryingperiods from 6, 12 and 24 h.10. Procedure10.1 Apply the coating to the glass plates or strips. Recordtime of application. Immediately attach the glass plates orstrips to the instrument, and lower the stylus carrier so that thesty
38、lus carrier is at the starting position. Lower the clean stylusgently into position on the strip. Always assure that the tip ofthe styli is clean and free from dried paint from previous testsprior to use. Switch on the motor and the stylus will be drawnalong the glass strip by the carrier.10.2 Alway
39、s mark the point on the glass strip where thestylus is first lowered into the wet film by use of a marker penor similar method. This will aid measurement of times alongthe strip during the assessment stage as it is often not obviousat what point the track starts, as paint flows back into thegroove.1
40、0.3 After drying, evaluate the glass plates or strips todetermine the stages of drying time as shown in Fig. 1. The useof magnification (73 etc.) will enhance the evaluation.TEST METHOD BCIRCULAR DRYING TIME11. Apparatus11.1 Circular Drying Time Recorder, consisting of a motorthat is mounted on a ru
41、bber-tipped tripod. The motor shaft isoriented in the vertical, with a pivotal arm assembly attached tothe shaft to operate a counter-poised vertical stylus consistingof a teflon stylus approximately 10 mm (38 in.) in diameter.The teflon stylus, typically under a weighted load of 12 g,scribes an arc
42、 in the drying film. The arm assembly includes acounter weight to permit adjusting the pressure on the needle tonear zero. The stylus is moved in a 360 arc at a selectedconstant speed. Recorders are available to cover various dryingtimes, such as 1, 6, 12 or 24 h.11.2 TemplateA transparent template
43、with scale gradua-tions, corresponding to the particular motor speed, is used fortiming the various stages of drying revealed by differencesobserved in the scribed pattern.12. Procedure12.1 Panel PreparationPrepare specimens following pro-cedures outlined in 8.1 through 8.4. Glass plates or panels,a
44、bout 150 by 150 mm (6 by 6 in.), are used for the determi-nation of drying times using this recording device.12.2 Apply the coating to the glass plates or panels. Recordtime of application. Immediately attach the glass plates orpanels to the instrument, and lower the clean stylus gently intoposition
45、 on the panel. Always assure that the tip of the stylus isclean and free from dried paint from previous tests prior to use.Switch on the motor so the stylus is drawn along the glasspanels.12.3 Always mark the point where the stylus is first loweredinto the wet film by use of a marker pen or similar
46、method. Thiswill aid measurement of times along the track during theassessment stage as it is often not obvious at what point thetrack starts, as paint flows back into the groove.12.4 After drying, evaluate the glass plates or panels todetermine the stages of drying time as shown in Fig. 2. The useo
47、f magnification (73 etc.) will enhance the evaluation.13. Report13.1 Report the following information:13.1.1 Test results of drying time determinations,13.1.2 Type of coating material used,13.1.3 Method of application,13.1.4 Film thickness used,13.1.5 Type of mechanical drying recorder used, and13.1
48、.6 All applicable conditions that deviated from thestandards as outlined or special conditions or tests used.14. Precision and Bias414.1 PrecisionIn an interlaboratory study of these testmethods, drying times were recorded in four laboratories forfour drying stages of four different coatings varying
49、 widely in4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D011119.D 5895 03 (2008)3drying characteristics. The intralaboratory coefficient of varia-tion was found to be 20.35 % with 56 df and the interlaboratorycoefficient 20.35 % with 42 df with no values discarded. Basedon these coefficients, the following criteria should be used forjudging at the 95 % confidence level, the acceptability ofresults:14.1.1 RepeatabilityTwo single results obtained by thesame operator at different times
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