1、Designation: D 4958 97 (Reapproved 2004)Standard Test Method forComparison of the Brush Drag of Latex Paints1This standard is issued under the fixed designation D 4958; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method is a standardized brushout procedurefor comparing the brush drag of architectural type solvent-borne p
3、aints.1.2 With slight modifications this test method is also appli-cable to solvent-borne paints.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if an
4、y, 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. Referenced Documents2.1 ASTM Standards:2D 1475 Test Method for Density of Liquid Coatings,
5、 Inks,and Related ProductsD 3924 Specification for Standard Environment for Condi-tioning and Testing Paint, Varnish, Lacquer and RelatedMaterialsD 3925 Practice for Sampling Liquid Paints and RelatedPigmented CoatingsD 4287 Test Method for High-Shear Viscosity Using aCone/Plate ViscometerD 5068 Pra
6、ctice for Preparation of Paint Brushes for Evalu-ation3. Terminology3.1 DefinitionsSee Paint/Coatings Dictionary3for defini-tion of terms used in this test method.3.1.1 brush-drag, nresistance encountered when applyinga coating by brush.4. Summary of Test Method4.1 A 50-mm (2-in.) polyester brush is
7、 used to apply the testpaint on a 1000-cm2(1.076-ft2) test area. The application ismade at a spreading rate of 9.82 m2/L (400 ft2/gal) and iscompleted in 30 to 35 s. The degree of brush drag is ratedsubjectively using a series of standard descriptive termscorresponding to numerical values of 1 to 10
8、. The rank order ofa set of samples is thereby established.5. Significance and Use5.1 As the brush drag of a paint increases, any naturaltendency on the part of the painter to overspread the paint isreduced. When all other factors are held constant, increasedbrush drag will result in greater film th
9、ickness with consequentimprovement in durability and hiding. Conversely, sometimesit might be preferred to have a lesser degree of brush drag foreasier application (that is, the amount of time and effort inapplying a paint to a specific area is reduced with a lesserdegree of brush drag).5.2 This tes
10、t method provides a standardized brushoutprocedure for the evaluation of brush drag as an alternative tocustomary informal ad hoc procedures. Its objective is tomaximize the reliability and precision with which this charac-teristic may be determined.NOTE 1The brush drag of paints is directly related
11、 to their high-shearviscosity. There is generally good rank order agreement between resultsobtained by this method and Test Method D 4287. The sensitivity of thisbrushout method has been found sufficient to distinguish between brush-abilities corresponding to high-shear viscosity differences not low
12、er than0.3 poise (0.03 Pa.s). Round robin data show that rank order agreementbetween the brushout and viscometric methods is poor when latex andsolvent-borne paints are part of the same comparison group. This is theresult of these two paint types having markedly different rheologicalproperties that
13、affect the relative perception of brush drag.46. Apparatus6.1 Brush, 50-mm (2-in.) polyester filament, 70-mm (234-in.) length-out, 14 mm (916 in.) thick, with a chiseled tip.NOTE 2All tests of a given series of paints, within or betweenlaboratories, should be carried out with commercially identical
14、brushes.6.2 Stopwatch.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.42 on Architectural Coatings.Current edition approved June 1, 2004. Published July 2004. Originally ap
15、provedin 1989. Last previous edition approved in 1997 as D 4958 97.2For referenced ASTM standards, visit the ASTM 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 we
16、bsite.3Available from Federation of Societies for Coatings Technology, 492 Norris-town Rd., Blue Bell, PA 19422.4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D011072.1Copyright ASTM International, 100 Barr Harbor Drive, PO Bo
17、x C700, West Conshohocken, PA 19428-2959, United States.6.3 Balance, capable of weighing accurately to 0.1 g.6.4 Test charts, with a sealed surface, having 1000 cm2(1.076 ft2) of test area.57. Sampling and Conditioning7.1 Sample in accordance with Practice D 3925.7.2 Condition the samples in accorda
18、nce with the Condi-tioning and Testing section of Specification D 3924.7.3 All testing should be performed under the same condi-tions.8. Procedure8.1 Do not change operators during the running of a seriesof specimens, since this will invalidate any conclusions as torank order.8.2 Determine the densi
19、ty in kilograms per litre (pounds pergallon) of the paint sample in accordance with Test MethodD 1475.8.3 Multiply the density by 1.221 to obtain the weight ofpaint in grams to apply on the specified test chart to obtain aspreading rate of 9.82 m2/L (400 ft2/gal).8.4 Conditioning of the Brush:8.4.1
20、Soak the brush in clean water, then spin rapidly toremove the water from the bristles as completely as possible inaccordance with practice D 5068.8.4.2 Dip the test brush into the specified paint to the depthshown below:Brush Width, mm (in.) Depth, mm (in.)50 and 62.5 (2 and 212)38(112)75 and 87.5 (
21、3 and 312)4534)100 (4) 50 (2)8.4.3 Hold the brush at the specified depth in the paint for 10s. Remove and hold the brush vertically for 30 s allowing anyexcess paint to drain.8.5 Place the test chart on the balance and weigh the correctamount of paint as calculated in 8.3 directly onto the center of
22、the card.8.6 Immediately tape the card onto a hard, flat surface, startthe stopwatch, and proceed to spread the paint using thepreviously conditioned 50-mm (2-in.) brush. Using long,steady brush strokes, alternately parallel and perpendicular tothe edge of the chart, cover the test area uniformly an
23、dcompletely in 30 to 35 s.8.7 Immediately assign and record a brush drag ratingaccording to the following series of qualitative descriptiveterms, first characterizing it by a verbal description, and thenby the corresponding number.1Very slight2Slight3Slight to moderate4Moderate5Moderate to considera
24、ble6Considerable7Considerable to pronounced8Pronounced9Very pronounced10Extreme8.8 Thoroughly clean the brush with warm water and spin itto remove excess water between tests.8.9 Repeat 8.2-8.8, using a fresh sample for each specimenin the set and rate the specimen as the mean of the two results.8.10
25、 If more than one sample has the same rating, brush outthe similarly rated specimens again, in close comparison. Ifsmall differences are perceived, then indicate these by assign-ing intermediate decimal values. If no difference is found thenthe original ratings stand.9. Interpretation of Results9.1
26、Tabulate the paints in order of their brush drag ratings,showing verbal descriptions and numerical ratings in separatecolumns.9.2 In a fourth rank order column, rank the paints from 1 ton (least to most brush drag), where n is the total number ofpaints in the series.9.3 Paints with the same qualitat
27、ive ratings should beassigned multiple rank numbers, with the mean of thosenumbers shown in parentheses, for example, 3 to 4 (3.5), 5 to7 (6). The mean ranking (in parentheses) is used to calculate agrand mean ranking when the same series of paints is rankedby more than one operator.10. Report10.1 R
28、eport the brush drag ranking as determined in Section9.11. Precision and Bias11.1 PrecisionIn an interlaboratory study of this testmethod in which five coatings varying widely in brush dragwere ranked by one operator in each of nine laboratories, twooperators in one laboratory, and three operators i
29、n anotherlaboratory, the coefficient of concordance (agreement in rank-ing) was found to be 0.84, reflecting the fact that seven of thefourteen operators agreed perfectly and four others reversedone of two adjacent pairs. The coefficient is statisticallysignificant at the 99.9 % confidence level.11.
30、2 BiasBias can not be determined for this test methodbecause there is no standard reference material.12. Keywords12.1 brushability; brush drag; drag; ease of brushing; highshear viscosity5Leneta Form 8H-BW, obtainable from The Leneta Co., P.O. Box 86, Ho-Ho-Kus, NJ 07423, has been found satisfactory
31、 for this purpose.D 4958 97 (2004)2ASTM 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 risk
32、of 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 are invited either for revision of this
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34、our views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 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).D 4958 97 (2004)3
