1、Designation:D494689(Reapproved 2012)Standard Test Method forBlocking Resistance of Architectural Paints1This standard is issued under the fixed designation D4946;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revisi
2、on.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 covers an accelerated procedure forevaluating the face-to-face blocking resistance of trades salespaints.This is not
3、to be confused with blocking resistance TestMethod D3003,which is concerned with blocking of industrialcoatings on metal substrates,nor with Test Method D2793which is concerned specifically with wood product finishes andreports results on a satisfactory or not satisfactory basis,ratherthan by the de
4、gree of blocking tendency as in this test method.1.2 The values stated in the SI units of measurement are tobe regarded as the standard.The values given in parenthesesare for information only.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is
5、 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:2D16 Terminology for Paint,Related Coatings,Materials,andApplicationsD2793 Test Metho
6、d for Block Resistance of Organic Coat-ings on Wood Panel SubstratesD3003 Test Method for Pressure Mottling and BlockingResistance of Organic Coatings on Metal Substrates3.Terminology3.1 Definitions:3.1.1 blocking,nthe undesirable sticking together of twopainted surfaces when pressed together or pla
7、ced in contactwith each other for an extended period of time,as referenced inTerminology D16.4.Summary of Test Method4.1 Dried paint films are placed face-to-face and a pressureof about 127 g/cm2(1.8 psi)is applied.These paint films areput into an oven for 30 min to make the test more stringent.Afte
8、r cooling,the blocked panels are peeled apart.The degreeof blocking is rated subjectively for tack or seal using a seriesof standard descriptive terms corresponding to numericalASTM values of 10 to 0.5.Significance and Use5.1 Dry paint often comes in contact with itself especially inwindow and door
9、areas and,depending on its hardness,thepressure,temperature,humidity,and duration of time thesurfaces are in contact,sometimes sticks to itself(blocks).Thisstringent test method can be used to compare and ratesubjectively the resistance of paints to blocking.6.Apparatus6.1 Conditioned Room,at 18 to
10、29.5C(65 to 85F)and 40to 60%relative humidity.6.2 Sealed Paper Test Charts,approximately 190 by 280mm(7.5 by 11 in.).6.3 Applicator Blade,13 to 15 cm(5 to 6 in.)wide,0.15-mm(6-mil)clearance.6.4 Oven,48 to 52C(115 to 125F).6.5 Rubber Stoppers,No.8,3.2 cm(1.25 in.)smallerdiameter.6.6 Weights,1000 g.6.
11、7 Scissors.6.8 Aluminum Tray or Pan,flat.7.Procedure7.1 Cast the paint to be tested on a sealed test chart using theapplicator blade.Condition coated panels in the conditionedroom for seven days.All painted panels should be kept free ofgrease,oil,or fingerprints since these will affect block resis-t
12、ance.7.2 After the panels have been conditioned,cut out six 3.8by 3.8-cm(112by 112-in.)sections from the painted chart.Start the cut at least 1.3 cm(12in.)away from the edge of thedrawdown.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Ap
13、plications and is the direct responsibility ofSubcommittee D01.42 on Architectural Coatings.Current edition approved July 1,2012.Published September 2012.Originallyapproved in 1989.Last previous edition approved in 2008 as D4946 89(2008)1.DOI:10.1520/D4946-89R12.2For referenced ASTM standards,visit
14、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 website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United S
15、tates1 7.3 Place the cut sections with the paint surfaces face-to-face for each paint to be tested.7.4 The weights,stoppers,and tray should be temperatureequilibrated in the oven prior to running the test.7.5 Place the face-to-face specimens in the oven on a flataluminum tray.Place a No.8 stopper on
16、 top,with the smalldiameter in contact with the specimens,then place a 1000-gweight on top of the stopper.This results in a pressure of 127g/cm2(1.8 psi)on the specimens.One weight and stopper is tobe used for each specimen to be tested.It is recommended that“pass”and“fail”paint controls be used in each test run and thatthe tests be run in triplicate.7.6 After exactly 30 min,take the stoppers and weights offthe test specimens and remove them from the oven.Allowthem to cool for12h in the conditio