1、Designation: D4752 10Standard 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 the case of revis
2、ion, 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. Scope*1.1 This practice describes a solvent rub technique forassessing the MEK resistance of ethyl silicate (i
3、norganic)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 fabricating shop.P
4、ractice 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 its use. It is ther
5、esponsibility 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 hazard information r
6、elating 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 Resistance ofOrganic Coati
7、ngs 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 double rub, nthe act
8、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 during the day, so d
9、oesthe 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 has been shown to c
10、orre-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 (MEK), in accordance
11、 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, respirator.6. Procedure6.1
12、 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.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct
13、responsibility ofSubcommittee D01.46 on Industrial Protective Coatings.Current edition approved Feb. 1, 2010. Published April 2010. Originallyapproved in 1987. Last previous edition approved in 2003 as D4752 03. DOI:10.1520/D4752-10.2Starr, T. L., Henton, L. E., Lewis, W. S., and Rideout, F. A., “Im
14、proved 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, Pittsburgh, PA 15213, www.sspc.org.3For referenced ASTM standards, visit the ASTM web
15、site, 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.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbo
16、r Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.NOTE 1Tap water may influence the cure of the zinc-rich primer.6.2 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 tes
17、tarea on the undamaged cleaned surface using 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
18、 the properly protected index finger into the 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 backtoward
19、s the operator. Complete each double rub (one 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 for
20、mer, record the number ofrubs when the substrate 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 Inspe
21、ct the test areas and the cloths. Rate the results 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
22、Resulting ratings.7.1.5 In the case of a zero 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 rati
23、ng scale is arbitrary and standardmethods for 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; doub
24、le rub method; drying orcuring; ethyl silicate (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
25、access the “goodness” of this practice. Using 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 twodif
26、ferent dry film thickness ranges; 2.7-4.5 mils 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/filmthic
27、kness combination.X1.2 An analysis of the means, (ANOM), was conductedon the performance data of Table X1.1. Figs. X1.1-X1.4illustrate the raw scores and the mean score reported by eachoperator. The 95 % confidence limits of the overall mean score(combined average score of the eight operators) are r
28、epresentedon each of the figures by dashed lines. The following obser-vations were 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
29、 dependent on coating thickness, thatis, higher 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
30、found to occur when this practiceis applied to thin film, 6-h cured primers. The second largestnumber of operators whose mean score deviated from the 95 %TABLE 1 Scale for Resistance RatingResistance Rating Description5 No effect on surface; no zinc on cloth after 50 doublerubs4 Burnished appearance
31、 in rubbed area; slight amount ofzinc on cloth after 50 double rubs3 Some marring and apparent depression 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 P
32、enetration to the substrate in 50 double rubs or lessD4752 102limits 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
33、-h cured primers or thick, 24-hcured 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
34、 1 Rub 2 Rub 3 Range Mean Standard DeviationA03332.01.4B333030C 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
35、3: Thick Film, 6-h cureOperator ID Rub1 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
36、.8J44400Overall Average 0.9 4.3 0.4D4752 103FIG. X1.1 Thin Film, 6-Hour CureD4752104FIG. X1.2 Thin-Film, 24-Hour CureD4752105FIG. X1.3 Thick Film, 6-Hour CureD4752106FIG. X1.4 Thick Film, 24-Hour CureD4752107SUMMARY OF CHANGESCommittee D01.46 has identified the location of selected changes to this s
37、tandard since the last issue(D4752 - 03) that may impact the use of this standard. (Approved February 1, 2010.)(1) Changed title from Test Method to Practice.(2) Section 2.1 and 6.2: replaced Test Methods D1186 andD1400 with Test Method D7091.(3) Section 5.2: changed from cheesecloth to 100 % cotton
38、cloth.ASTM 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 riskof infringement of such right
39、s, 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 standard or for additional s
40、tandardsand 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 known to the ASTM C
41、ommittee 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D4752 108
