1、Designation: D4752 10 (Reapproved 2015)Standard Practice forMeasuring MEK Resistance of Ethyl Silicate (Inorganic)Zinc-Rich Primers by Solvent Rub1This standard is issued under the fixed designation D4752; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 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 This practice describes a solvent rub technique forassessing the MEK resistance of
3、ethyl silicate (inorganic)zinc-rich primers. The MEK resistance of some two-component ethyl silicate zinc-rich primers has been shown tocorrelate well with the cure of the primer as determined bydiffuse reflectance infrared spectroscopy.2The technique canbe used in the laboratory, field, or in the f
4、abricating shop.Practice D5402 is the preferred method for organic coatings.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with it
5、s 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. Specific hazardstatements are given in Section 6. Consult suppliers MaterialSafety Data Sheet(s) for specific haz
6、ard information relating tothe solvent used.2. Referenced Documents2.1 ASTM Standards:3D740 Specification for Methyl Ethyl KetoneD4138 Practices for Measurement of Dry Film Thickness ofProtective Coating Systems by Destructive, Cross-Sectioning MeansD5402 Practice for Assessing the Solvent Resistanc
7、e ofOrganic Coatings Using Solvent RubsD7091 Practice for Nondestructive Measurement of DryFilm Thickness of Nonmagnetic Coatings Applied toFerrous Metals and Nonmagnetic, Nonconductive Coat-ings Applied to Non-Ferrous Metals3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 doub
8、le rub, nthe act of rubbing a solvent saturatedcloth in one complete forward and backward motion over acoated surface.4. Significance and Use4.1 Ethyl silicate zinc-rich primers cure by the reaction ofthe vehicle with moisture, thereby providing a binder. Asrelative humidity and temperature vary dur
9、ing the day, so doesthe rate of cure.Acertain minimum degree of cure is necessaryprior to topcoating. It has been shown that the degree of cureof ethyl silicate zinc-rich primers can be measured by thechemical changes occurring using diffuse reflectance infraredspectroscopy.2This solvent rub test ha
10、s been shown to corre-late well with the infrared spectroscopic results of sometwo-component ethyl silicate inorganic zinc systems.4.2 The cure rating required for the application of specifictopcoats must be agreed upon before the practice is used.5. Reagents and Materials5.1 Methyl Ethyl Ketone (ME
11、K), in accordance with Speci-fication D740.5.2 100 % Cotton, Shop Cloth, approximately 300 by 300mm (12 by 12 in.) contrasting in color to the coating to beevaluated.5.3 Squeeze Bottle.5.4 Proper Safety Equipment, as determined from the sol-vent MSDS, for example, solvent resistant gloves, respirato
12、r.6. Procedure6.1 Select areas on the primer surface at least 150 mm (6 in.)long on which to run the tests. Clean the surface with tap wateror dry cloth to remove loose material.NOTE 1Tap water may influence the cure of the zinc-rich primer.1This practice is under the jurisdiction of ASTM Committee
13、D01 on Paint andRelated Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.46 on Industrial Protective Coatings.Current edition approved Feb. 1, 2015. Published February 2015. Originallyapproved in 1987. Last previous edition approved in 2010 as D4752 10. DOI:1
14、0.1520/D4752-10R15.2Starr, T. L., Henton, L. E., Lewis, W. S., and Rideout, F. A., “Improved FieldReliability of High Performance Coating Systems: Phase IIDevelop Proceduresand Criteria in Critical Performance Areas,” available from SSPC: The Society forProtective Coatings, 40 24th St., Sixth Floor,
15、 Pittsburgh, PA 15213, www.sspc.org.3For 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 Internatio
16、nal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16.2 Measure the dry film thickness of the primer in theselected areas in accordance with Test Methods D7091 orD4138. Mark a 150- by 25-mm (6- by 1-in.) rectangular testarea on the undamaged cleaned surface using
17、 a pencil or othersuitable solvent resistant marker.6.3 Fold the cloth into a pad of double thickness andsaturate it to a dripping wet condition with the methyl ethylketone. Do not allow more than 10 s to elapse beforeproceeding to the next steps.6.4 Place the properly protected index finger into th
18、e centerof the pad while holding excess cloth with the thumb andremaining fingers of the same hand. With the index finger at a45 angle to the test surface, rub the rectangular test area withmoderate pressure first away from the operator and then backtowards the operator. Complete each double rub (on
19、e forwardand back motion) in about 1 s.6.5 Continue rubbing the surface with the MEK saturatedpad, wetting the pad as necessary without lifting it from thesurface, until either the metal substrate is exposed or 50 doublerubs have been completed. If the former, record the number ofrubs when the subst
20、rate is exposed.6.6 Select an adjacent area to be used as a control. Repeat6.1 6.5, except use a dry cloth to establish the effect ofburnishing without the influence of MEK. Use this area as thecontrol to visually show the appearance of No Effect.6.7 Inspect the test areas and the cloths. Rate the r
21、esults inaccordance with Table 1.7. Report7.1 Report, as a minimum, the following information:7.1.1 Dry film thickness of the primer.7.1.2 Elapsed time between the application of the primerand the running of the tests.7.1.3 Number of tests conducted.7.1.4 Resulting ratings.7.1.5 In the case of a zer
22、o rating, number of double rubsrequired to expose the substrate.7.1.6 Field and Fabricating Shop TestsIdentification ofthe area or piece tested.8. Precision and Bias8.1 PrecisionIt is not practicable to specify the precisionof this procedure since the rating scale is arbitrary and standardmethods fo
23、r conducting round-robin studies and analyzing databased on an arbitrary rating scale are not available. SeeAppendix X1 “Goodness.”8.2 BiasSince there is no acceptable reference material,bias cannot be determined.9. Keywords9.1 curing characteristics; double rub method; drying orcuring; ethyl silica
24、te (inorganic) primer; methyl ethyl ketone;MEK (methyl ethyl ketone) resistance; primer; solvent rubmethod; visual examination; zinc-rich primerAPPENDIX(Nonmandatory Information)X1. GOODNESSX1.1 An intra-lab round-robin evaluation was conducted inorder to access the “goodness” of this practice. Usin
25、g theprocedure outlines in this practice, eight different operatorswere asked to rate, in triplicate, the methyl ethyl ketone (MEK)rub resistance of a particular inorganic zinc-rich primer. Theprimer was separately applied to multiple test panels at twodifferent dry film thickness ranges; 2.7-4.5 mi
26、ls and 6.8-8.0mils. Separate test panels corresponding to each coatingthickness category were scored after a 6-h cure period and a24-h cure period. Performance ratings and general statisticalinformation have been in Table X1.1 for each cure period/filmthickness combination.X1.2 An analysis of the me
27、ans, (ANOM), was conducted onthe performance data of Table X1.1. Figs. X1.1-X1.4 illustratethe raw scores and the mean score reported by each operator.The 95 % confidence limits of the overall mean score (com-bined average score of the eight operators) are represented oneach of the figures by dashed
28、 lines. The following observationswere made through this analysis:X1.2.1 Rub results are cure time dependent, that is, higherrub scores are associated with longer cure periods, lower rubscores are associated with shorter cure periods.X1.2.2 Rub results are dependent on coating thickness, thatis, hig
29、her rub scores are associated with thick coatings films,lower rub scores are associated with thinner coating films.X1.2.3 From the plots, the largest number of operatorswhose mean score deviated from the 95 % confidence limits ofthe overall mean score was found to occur when this practiceis applied
30、to thin film, 6-h cured primers. The second largestTABLE 1 Scale for Resistance RatingResistance Rating Description5 No effect on surface; no zinc on cloth after 50 doublerubs4 Burnished appearance in rubbed area; slight amount ofzinc on cloth after 50 double rubs3 Some marring and apparent depressi
31、on of the film after50 double rubs2 Heavy marring; obvious depression in the film after 50double rubs1 Heavy depression in the film but no actual penetration tothe substrate after 50 double rubs0 Penetration to the substrate in 50 double rubs or lessD4752 10 (2015)2number of operators whose mean sco
32、re deviated from the 95 %limits of the overall score was found to occur in the case of thethin film 24-h cured primers.X1.2.4 All operators had mean scores within the 95 %confidence limits of the overall mean score when this practicewas applied to either thick, 6-h cured primers or thick, 24-hcured
33、primers.X1.3 The findings of this practices round-robin evaluationhave been offered in this appendix to serve as a reference orguide for operators wishing to utilize this practice.TABLE X1.1 Round Robin Resistance RatingCase 1: Thin Film, 6-hr cureOperator ID Rub 1 Rub 2 Rub 3 Range Mean Standard De
34、viationA03332.01.4B333030C 011 5D .0.E4232308F0101 5G3330.0.H101170Overall Average 1 1.9 0.5Case 2: Thin Film, 24-h cureOperator ID Rub 1 Rub 2 Rub 3 Range Mean Standard DeviationA54414.30.5BD44400F 5514.70.5G55505H44513I 4404.00.JOverall Average 0.5 4.3 0.2Case 3: Thick Film, 6-h cureOperator ID Ru
35、b1 Rub2 Rub3 Range Mean Standard DeviationA44404.00.BCD33303.00.E4331 5F0455 2G33303.00.H 431 5Overall Average 0.9 3.5 0.4Case 4: Thick Film, 24-h cureOperator ID Rub1 Rub 2 Rub 3 Range Mean Standard DeviationA44514.30.5B5441D 3417F45414.30.5G555050H 5517I 3424.0.8J44400Overall Average 0.9 4.3 0.4D4
36、752 10 (2015)3FIG.X1.1ThinFilm,6-HourCureD4752 10 (2015)4FIG.X1.2Thin-Film,24-HourCureD4752 10 (2015)5FIG.X1.3ThickFilm,6-HourCureD4752 10 (2015)6FIG.X1.4ThickFilm,24-HourCureD4752 10 (2015)7ASTM International takes no position respecting the validity of any patent rights asserted in connection with
37、 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.This standard is subject to revision at any time by the responsible techni
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39、n 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 shown below.This standard is copyrighted by ASTM International, 100 Barr Harb
40、or 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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 10 (2015)8
