1、Designation: D4946 89 (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
2、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 test method covers an accelerated procedure forevaluating the face-to-face blocking resistance of trades salespaints.
3、This is not 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, rathe
4、rthan by the degree 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
5、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:2D16 Terminology for Paint, Related Coatings, Materials, andAppli
6、cationsD2793 Test Method 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 whe
7、n pressed together or placed 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
8、 the test more stringent.After 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 itse
9、lf especially inwindow and door 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
10、. Apparatus6.1 Conditioned Room, at 18 to 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
11、. 8, 3.2 cm (1.25 in.) smallerdiameter.6.6 Weights, 1000 g.6.7 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 o
12、fgrease, oil, or fingerprints since these will affect block resis-tance.7.2 After the panels have been conditioned, cut out six 3.8by 3.8-cm (112 by 112-in.) sections from the painted chart.Start the cut at least 1.3 cm (12 in.) away from the edge of thedrawdown.1This test method is under the jurisd
13、iction 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 July 1, 2012. Published September 2012. Originallyapproved in 1989. Last previous edition approved in 2008
14、as D4946 89 (2008)1.DOI: 10.1520/D4946-89R12.2For 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 website.Copyright ASTM I
15、nternational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17.3 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.
16、5 Place the face-to-face specimens in the oven on a flataluminum tray. Place a No. 8 stopper on 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
17、 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 for12 h in the c
18、onditioned room before determin-ing the block resistance.7.7 After cooling, separate the specimens by peeling themapart with a slow and steady force at about 180 from eachother forming a “T” pattern during beginning of the separation.It is necessary to put the specimen next to the ear whileseparatin
19、g to actually hear the degree of tack. Rate for blockingresistance on a scale of 0 to 10 (see 8.2).8. Interpretation of Results8.1 Blocking resistance is rated on a scale of 10 to 0, whichcorresponds to a subjective tack (sound of separation whenpeeled) or seal (the complete sticking together) ratin
20、g deter-mined by the operator. This rating system is defined in 8.2 inthe appropriate descriptive terms. The degree of seal is theestimated area on the specimens where the paint surfacesadhere and some of the paper tears away from the chart whenpeeled.8.2 Blocking Resistance Ratings:BlockingResistan
21、ceNumerical RatingsType of Separation Performance10 no tack perfect9 trace tack excellent8 very slight tack very good7 very slight to slight tack good to very good6 slight tack good5 moderate tack fair4 very tacky; no seal poor to fair3 5 to 25 % seal poor2 25 to 50 % seal poor1 50 to 75 % seal very
22、 poor0 75 to 100 % seal very poor9. Report9.1 Report the blocking resistance rating determined inaccordance with 8.2.10. Precision10.1 Data are unavailable for a conventional precisionstatement. However, based on actual laboratory experience,with experienced operators, the repeatability is estimated
23、 to beplus or minus one blocking resistance unit. Numerical valuesmay differ from operator to operator but relative rankingshould be about the same. As in many tests the precisionimproves with practice.11. Keywords11.1 blocking; blocking resistance; sticking; tackASTM International takes no position
24、 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 responsibility.T
25、his 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 In
26、ternational 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 known to the ASTM Committee on Standards, at the address show
27、n 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D4946 89 (2012)2
