ASTM D4400-2018 Standard Test Method for Sag Resistance of Paints Using a Multinotch Applicator.pdf

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1、Designation: D4400 99 (Reapproved 2012)1D4400 18Standard Test Method forSag Resistance of Paints Using a Multinotch Applicator1This standard is issued under the fixed designation D4400; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio

2、n, 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.This standard has been approved for use by agencies of the U.S. Department of Defense.1 NOTESole source of supply f

3、ootnote was removed editorially and new footnote placed in Precision section in Novem-ber 2012.INTRODUCTIONThe multinotch applicator used in this test method is a drawdown blade with a series of notches ofsuccessively higher clearance, referred to as the Anti-Sag Meter. See Fig. 1 and Fig. 2 for are

4、presentative diagram and photograph. The numerical value for sag resistance obtained with thisinstrument is referred to as the Anti-Sag Index.Anti-Sag Meters are made with several clearance ranges for different types of coatings (see 5.1 andTable 1). In developing this standard the task group used a

5、n instrument with a range from 4 to 24 mils,but the method is applicable to any clearance range, and results using instruments with overlappingranges correlate and have equal validity.The basic method was developed in 19622 and is referenced in U.S. Federal specificationsTT-E-508, TT-E-506, and TT-P

6、-1511.Apreshear program is essential for a drawdown sag test to duplicate the breakdown in structure thatoccurs when thixotropic paints are applied by brushout or other practical application methods. Theprocedures therefore include the preshearing of paints just prior to making test applications.1.

7、Scope1.1 This test method covers the laboratory determination of the sag resistance of aqueous and nonaqueous liquid coatings at anylevel of sag resistance.1.2 The values stated in either SI units or inch-pound units are to be regarded separately as the standard. The values given inparentheses are f

8、or information only.stated in each system may not be exact equivalents; therefore, each system shall be usedindependently of the other. Combining values from the two systems may result in non-conformance with the standard.NOTE 1Because the only manufacturer of the applicator know to the committee ma

9、nufactures to inch-pound units, inch-pound units will be regardedas the standard when referring to the applicator.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate s

10、afety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Dev

11、elopment of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.1 This test method is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibi

12、lity ofSubcommittee D01.42 on Architectural Coatings.Current edition approved May 15, 2012Sept. 15, 2018. Published May 2012October 2018. Originally approved in 1984. Last previous edition approved in 20072012 asD4400 99 (2007).(2012)1. DOI: 10.1520/D4400-99R12E01.10.1520/D4400-18.2 “Design of an Im

13、proved Sag Tester,” Offcial Digest, Vol 34, No. 453, October 1962.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict al

14、l changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-29

15、59. United States12. Referenced Documents2.1 ASTM Standards:3D2196 Test Methods for Rheological Properties of Non-Newtonian Materials by Rotational Viscometer2.2 U.S. Federal Specifications:4Fed. Spec. TT-E-508 Alkyd semi-gloss enamelFed. Spec. TT-E-506 Alkyd gloss enamelFed. Spec. TT-P-1511 Interio

16、r latex gloss and semi-gloss finishes3. Summary of Test Method3.1 After preshearing, the coating is applied to a test chart with a multinotch applicator. The charts are immediately hungvertically with the drawdown stripes horizontal, similar to rungs of a ladder, with the thinnest stripe at the top.

17、 After drying in thisposition, the drawdown is examined and rated for sagging. A typical sag pattern obtained by this procedure is shown in Fig. 3.4. Significance and Use4.1 Evaluation of sag resistance is essential in quality control for both producers and purchasers of coatings. Practicalapplicati

18、on tests are poor in reproducibility, while viscometric methods, for example Test Methods D2196, are time-consuming andlack the convincing aspect of actual sagging. This method provides simple and rapid tests, whereby sag resistance is demonstratedby a visible sag pattern, and is rated objectively i

19、n terms of numerical values that correlate with brushout test observations.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the

20、 ASTM website.4 Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, DLA Document Services, Building 4/D, 700 Robbins Ave., Philadelphia, PA19111-5098, http:/www.dodssp.daps.mil.19111-5094, http:/quicksearch.dla.mil.FIG. 1 Diagram of the Medium Range Anti-Sag MeterFIG. 2

21、Medium Range Anti-Sag MeterD4400 1825. Apparatus5.1 Multinotch Applicator, Anti-Sag Meter, a drawdown blade with a series of notches of successively higher clearance. Selecta clearance range suitable for the type of coating under test in accordance with Table 1.5.2 Test Surfaces, sealed, smooth-surf

22、aced paper test charts, with sizes and designs as follows:5.2.1 Black and White Charts, about 193 by 288 mm (758 by 1138 in.), the black area comprising about 140 mm (512 in.)centered on the drawdown path. A chart of this design is shown in Figs. 3 and 4.5.2.2 Plain White Charts, about 193 by 285 mm

23、 (758 by 1114 in.).5.3 Glass Drawdown Plate, plus straightedge guide for attachment thereto.5.4 Catch-papers, thin sheets of sealed paper, for catching surplus paint at the completion of a drawdown.5.5 Equipment for the Preshearing of Aqueous Coatings:TABLE 1 Anti-Sag MetersAvailable RangesRange For

24、 Coating Type: Notch ClearancesARange For Coating Type: Notch ClearancesAASM-1 Standard Solvent-borne architectural Mils 3 4 5 6 7 8 9 10 11 12m 75 100 125 150 175 200 225 250 275 300ASM-2 Low Industrial O.E.M. coatings Mils 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6m 25 38 50 63 75 88 100 113 125 138 150ASM-3

25、 High High build coatings Mils 14 16 18 20 25 30 35 40 45 50 60m 350 400 450 500 625 750 875 1000 1125 1250 1500ASM-4 Medium Water borne architectural Mils 4 6 8 10 12 14 16 18 20 22 24m 100 150 200 250 300 350 400 450 500 550 600A Mils are exact. Wet film thickness is about half of clearance. The c

26、urrently availableAnti-Sag Meters are manufactured and marked in mils (thousandths of an inch). TheSI values given in this table are approximate conversions.FIG. 3 Typical Sag PatternNOTE 1Note use of straightedge guide.FIG. 4 Drawing Down with the Anti-Sag MeterD4400 1835.5.1 Syringe, 10-mL, dispos

27、able plastic type.5.5.2 Syringe Needle, 15 g by 40 mm (112 in.) to fit syringe.5.5.3 Syringe Extension Tubing, clear vinyl, inside diameter 3.2 mm (18 in.), outside diameter 5 mm (36 in.).5.6 Equipment for the Preshearing of Nonaqueous Coatings:5.6.1 Rotary Mechanical Stirrer, variable speed.5.6.2 C

28、ircular Mixing Paddle, diameter approximately 48 mm (178 in.).5.6.3 Mixing Container, cylindrical jar or can with capacity of up to 500 mL (1 pt).6. Procedure6.1 Preparation of Sample:6.1.1 Stir thoroughly with a spatula in the original container.6.1.2 Strain if necessary to remove large particles o

29、r skins.6.1.3 Adjust the temperature of the coating to 23 6 2C (73.5 6 3.5F).6.2 Preshearing with Syringe and Needle (Aqueous Coatings):6.2.1 Prepare the paint as described in 6.1.6.2.2 Cut a 60-mm (212-in.) length of syringe extension tubing and attach it to the syringe.6.2.3 Press the syringe barr

30、el firmly to expel air, dip the end of the syringe into the coating, pump slightly to expel remainingair, then withdraw 8 mL of coating.coating (approximately 20 mL for ASM-3 Anti-Sag Meter). Enough coating should bewithdrawn to have excess leftover after drawing down.6.2.4 Remove and discard the ex

31、tension tubing and then attach a syringe needle.6.2.5 Eject the contents of the syringe in front of the applicator as rapidly as possible, with firm, steady pressure.6.3 Preshearing with a Rotary Mechanical Mixer (Nonaqueous Coatings):6.3.1 Prepare the paint as described in 6.1 and fill the mixing c

32、ontainer slightly more than half. Set the container under the stirrerso that the paddle is about 5 mm (14 in.) from the bottom.6.3.2 Mix vigorously for 1 min at a speed sufficient to form a moderate vortex, with the entire contents of the can in rapidcircular motion. Rotor speeds of 1300 to 3600 r/m

33、in have been found satisfactory, the optimum speed depending on the relativediameters of the mixing paddle and container. For referee tests the operators should agree upon the specific container, paddle, andmixing speed.6.3.3 Immediately after mixing place about 8 mL of paint in front of the applica

34、tor and draw down in accordance with 6.4.6.4 Application of the Test Coating:6.4.1 Affix a suitable test chart onto the drawdown plate. Use black and white charts in accordance with 5.2.1 for light ormoderately dark colored coatings and white charts in accordance with 5.2.2 for very dark coatings.6.

35、4.2 Fasten the straightedge onto the drawdown plate in a suitable position.6.4.3 Place theAnti-Sag Meter at the far end of the chart, the open side toward the operator and shoulder against the straightedgeguide.6.4.4 If desired, position a catch-paper just underneath the lower edge of the chart.6.4.

36、5 Preshear in accordance with 6.2 or 6.3 and immediately draw down the coating at a uniform speed of about 150 mm (6in.)/s, with the applicator pressed against the straightedge to maintain a straight path. See Fig. 4 for illustration of this step.6.4.6 Immediately hang the chart with the drawdown st

37、ripes in a horizontal position like rungs in a standing ladder, the thinneststripe at the top, and allow to dry in that position. A typical test pattern derived using this procedure is shown in Fig. 3.6.5 Rating the Drawdown:6.5.1 When the film is dry, note the notch numbers marked on the Anti-Sag M

38、eter and identify the corresponding stripesaccordingly.6.5.2 Observe the sag pattern, ignoring the bottom stripe, which serves only as a position reference for the stripe above it, andthe leading and trailing edges of the drawdown, considering only the central 140 mm (512 in.) of the blade path. Thi

39、s correspondsto the black area of the black and white chart described in 5.2.1. (See Fig. 3 for a typical sag pattern of this type.)6.5.3 Select the lowest (thickest) stripe that has resisted crossing the gap to touch the next lower stripe. This is referred to asthe index stripe.6.5.4 Estimate the d

40、egree to which the next lower stripe (the post-index stripe) has merged with the one below it, and determinethe corresponding addendum fraction, as specified in Table 2.6.5.5 Multiply the fraction from 6.5.4 by the difference between the index and post-index stripe number to obtain the indexaddendum

41、.6.5.6 Add the index addendum to the index stripe number to obtain the Anti-Sag Index and record same.7. Report7.1 Report the Anti-Sag Index of the coating as recorded in 6.5.6.D4400 1848. Precision 5,68.1 CorrelationIn an interlaboratory study in which operators in seven laboratories tested six wat

42、er-reducible paints coveringa wide range of sag resistance and in five laboratories tested four solvent-reducible paints covering a wide range of sag resistance,the Spearman Rank Correlation Coefficient was 0.92 versus brushouts (a coefficient of 1.0 indicates perfect agreement in ranking).8.2 Sensi

43、tivityIn the interlaboratory study described in 8.1, the sensitivity criterion values have been computed to be 4 forbrushouts versus 11 for this procedure. The latter is thus approximately three times more sensitive to differences in sag resistancethan brushouts.8.3 Precision:8.3.1 Two interlaborato

44、ry tests were conducted to establish the precision of this test method. The first test was that describedin 8.1. The second test consisted of operators in five laboratories performing three tests on each of three paints. On the basis ofthe second interlaboratory test, the within-laboratory pooled co

45、efficients of variations for both water- and solvent-reducible paintswere 4.4 %. On the basis of the first interlaboratory test, the between-laboratory pooled coefficient of variation was found to be12.4 % for water-reducible paints and 8.8 % for solvent-reducible paints. Based on these coefficients

46、 of variation, the followingcriteria should be used for judging the acceptability of results at the 95 % confidence level:8.3.1.1 RepeatabilityTwo results obtained by the same operator for either water-reducible or solvent-reducible paints shouldbe considered suspect if they differ by more than 10.7

47、 %.8.3.1.2 ReproducibilityTwo results obtained by operators in different laboratories should be suspect if they differ by more than34.4 % for water-reducible paints and 23.4 % for solvent-reducible paints.9. Keywords9.1 Anti-Sag Index; rheological properties; sag-resistanceASTM International takes n

48、o 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 respon

49、sibility.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 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 kno