1、Designation: D 4752 03Standard Test Method forMeasuring MEK Resistance of Ethyl Silicate (Inorganic)Zinc-Rich Primers by Solvent Rub1This standard is issued under the fixed designation D 4752; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、revision, the year of last 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 describes a solvent rub technique forassessing the MEK resistance of ethyl sil
3、icate (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 fabricatin
4、g shop.Practice D 5402 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. I
5、t 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 hazard info
6、rmation relating tothe solvent used.2. Referenced Documents2.1 ASTM Standards:D 740 Specification for Methyl Ethyl Ketone3D 1186 Test Methods for Nondestructive Measurement ofDry Film Thickness of Nonmagnetic Coatings Applied toa Ferrous Base4D 1400 Test Method for Nondestructive Measurement ofDry F
7、ilm Thickness of Nonconductive CoatingsApplied toa Nonferrous Metal Base4D 4138 Test Methods for Measurement of Dry Film Thick-ness of Protective Coating Systems by Destructive Means5D 5402 Practice for Assessing the Solvent Resistance ofOrganic Coatings Using Solvent Rubs53. Terminology3.1 Definiti
8、ons of Terms Specific to This Standard:3.1.1 double rubthe 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
9、. Asrelative humidity and temperature vary during 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
10、infraredspectroscopy.2This solvent rub test has 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 test method is used.5.
11、Reagents and Materials5.1 Methyl Ethyl Ketone (MEK), in accordance with Speci-fication D 740.5.2 Cheesecloth, 100 % cotton mesh size grade 28 by 24approximately 300- by 300-mm (12- by 12-in.) and contrastingin color to the coating being evaluated, or other mutuallyagreed upon cloth.5.3 Squeeze Bottl
12、e.5.4 Proper Safety Equipment, as determined from the sol-vent MSDS, for example, solvent resistant gloves, respirator.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.1This
13、 test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.46 on Industrial Protective Coatings.Current edition approved Jan. 10, 2003. Published March 2003. Originallyapproved in 1987. La
14、st previous edition approved in 1998 as D 4752 98.2Starr, 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 Coat
15、ings, 40 24th St., Sixth Floor, Pittsburgh, PA 15213, www.sspc.org.3Annual Book of ASTM Standards, Vol 06.04.4Annual Book of ASTM Standards, Vol 06.01.5Annual Book of ASTM Standards, Vol 06.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United
16、 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 D 1186,D 1400 or D 4138. Mark a 150- by 25-mm (6- by 1-in.)rectangular test area on the undamaged cleaned surface using apencil
17、 or other suitable solvent resistant marker.6.3 Fold the cheesecloth into a pad of double thickness andsaturate it to a dipping 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 the c
18、enterof 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 (one f
19、orwardand 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 substrat
20、e is exposed.6.6 Select an adjacent area to be used as a control. Repeat6.1-6.5, except use a dry cheesecloth 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 cheesecloths. R
21、ate theresults in accordance 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
22、 of a zero rating, number of double rubsrequired to expose the substrate.7.1.6 Field and Fabricating Shop Tests Identification 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 standard
23、methods 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; double rub method; drying orcuring; et
24、hyl 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 access the “goodness” of this test
25、 method. Using theprocedure outlines in this test method, 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 ra
26、nges; 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/filmthickness combination.X1.2 An an
27、alysis 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 representedon each of the fig
28、ures 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 dependent on coating thickn
29、ess, 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 found to occur when this tes
30、tmethod is applied to thin film, 6-h cured primers. The secondlargest number of operators whose mean score deviated fromTABLE 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 ofz
31、inc 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 Penetration to the substrate in 50
32、double rubs or lessD4752032the 95 % limits of the overall score was found to occur in thecase of the thin 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 testmethod was applied to either thick, 6-h cured primers or thi
33、ck,24-h cured primers.X1.3 The findings of this test methods round-robin evalu-ation have been offered in this appendix to serve as a referenceor guide for operators wishing to utilize this test method.TABLE X1.1 Round Robin Resistance RatingCase 1: Thin Film, 6-hr cureOperator ID Rub 1 Rub 2 Rub 3
34、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 3: Thick Film,
35、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 3424.0.8J44400Overall
36、 Average 0.9 4.3 0.4D4752033FIG.X1.1ThinFilm,6-HourCureD4752034FIG.X1.2Thin-Film,24-HourCureD4752035FIG.X1.3ThickFilm,6-HourCureD4752036FIG.X1.4ThickFilm,24-HourCureD4752037ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentione
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40、700, 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).D4752038
