1、Designation: D2454 14Standard Practice forDetermining the Effect of Overbaking on Organic Coatings1This standard is issued under the fixed designation D2454; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision
2、. 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 covers the determination of the time-temperature effect of overbaking on the physical and chemicalproperties of orga
3、nic coatings.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of whoever uses this standard to
4、consult andestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.Specific hazard statements are given in Section 7.2. Referenced Documents2.1 ASTM Standards:2D522 Test Methods for Mandrel Bend Test of AttachedOrganic CoatingsD523 Te
5、st Method for Specular GlossD609 Practice for Preparation of Cold-Rolled Steel Panelsfor Testing Paint, Varnish, Conversion Coatings, andRelated Coating ProductsD823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Related Products on Test PanelsD1005 Test Method for Measurem
6、ent of Dry-Film Thick-ness of Organic Coatings Using MicrometersD1308 Test Method for Effect of Household Chemicals onClear and Pigmented Organic FinishesD1640 Test Methods for Drying, Curing, or Film Formationof Organic Coatings at Room TemperatureD1729 Practice for Visual Appraisal of Colors and C
7、olorDifferences of Diffusely-Illuminated Opaque MaterialsD1730 Practices for Preparation of Aluminum andAluminum-Alloy Surfaces for PaintingD1731 Practices for Preparation of Hot-Dip Aluminum Sur-faces for PaintingD2197 Test Method for Adhesion of Organic Coatings byScrape AdhesionD2201 Practice for
8、 Preparation of Zinc-Coated and Zinc-Alloy-Coated Steel Panels for Testing Paint and RelatedCoating ProductsD2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinatesD2794 Test Method for Resistance of Organic Coatings tothe Effects of Rapid
9、 Deformation (Impact)D3359 Test Methods for Measuring Adhesion by Tape TestD3363 Test Method for Film Hardness by Pencil TestD6386 Practice for Preparation of Zinc (Hot-Dip Galva-nized) Coated Iron and Steel Product and HardwareSurfaces for PaintingD7091 Practice for Nondestructive Measurement of Dr
10、yFilm Thickness of Nonmagnetic Coatings Applied toFerrous Metals and Nonmagnetic, Nonconductive Coat-ings Applied to Non-Ferrous MetalsD7396 Guide for Preparation of New, Continuous Zinc-Coated (Galvanized) Steel Surfaces for PaintingE805 Practice for Identification of Instrumental Methods ofColor o
11、r Color-Difference Measurement of Materials3. Terminology3.1 Definitions:3.1.1 overbaking, nan exposure of the coating to a mod-erately higher temperature or to a longer period of baking, orboth, than recommended by the manufacturer of the coating fornormal curing.3.1.1.1 DiscussionThis condition is
12、 in contrast to “heatresistance” which is a parameter relating to the service life ofa coating.4. Summary of Practice4.1 Four panels are prepared and baked at the schedulenormally recommended for the coating. Two of the panels arethen removed and the remaining two are subjected to anadditional overb
13、ake in which the time and temperature aremutually agreed upon between the purchaser and the seller.The sets of panels, after a suitable conditioning interval, are1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct
14、 responsibility ofSubcommittee D01.27 on Accelerated Testing.Current edition approved Feb. 1, 2014. Published March 2014. Originallyapproved in 1966. Last previous edition approved in 2008 as D2454 08. DOI:10.1520/D2454-14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orconta
15、ct ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Co
16、nshohocken, PA 19428-2959. United States1then evaluated for the properties that are compatible with thesubstrate. Among these are gloss, color, flexibility, adhesion,impact resistance, and resistance to reagents. Note that glasssubstrates should not be tested for impact, and zinc-coatedsubstrates ca
17、n influence both flexibility and impact.5. Significance and Use5.1 Most coatings are designed for a specific baking timeand temperature. For a variety of reasons (line stoppages,rerouting back through ovens, oven overheating, etc.) theprescribed time or temperature, or both, of the bake is oftenexce
18、eded. This practice has been found to be useful inevaluating the effects of overbakes on coatings.6. Materials6.1 Standard Baking-Type Coating mutually agreed uponbetween the purchaser and the seller.7. Hazards7.1 The flash points of most solvents used in many organiccoatings and related products ar
19、e low enough that adequateventilation is needed to avoid exceeding 25 % of the lowerexplosive limits of the solvents when test panels are beingprepared and baked. As these materials are considered toxic,take care to avoid inhalation of solvent vapor and unnecessarycontact of solvent with the skin.8.
20、 Procedure8.1 Application of Organic Coating:8.1.1 Apply coatings to steel panels prepared in accordancewith Practice D609.8.1.2 Apply coatings to zinc-coated surfaces prepared inaccordance with Guide D7396 or Practice D6386, when zinchas been applied by the hot-dip method or by electroplating.8.1.3
21、 Apply coatings to nonpassivated galvanized steelprepared in accordance with Guide D7396 Practice D2201,when the zinc is applied by a continuous galvanizing methodusing an aluminum-bearing zinc.8.1.4 Apply coatings to aluminum surfaces on all-aluminummaterials prepared in accordance with Practices D
22、1730.8.1.5 Apply coatings to hot-dip aluminum coated surfacesprepared in accordance with Practices D1731.8.1.6 In cases where a primer is used in practice under thetopcoat, apply the entire system to the panels. The filmthickness of each coat shall be mutually agreed upon betweenthe purchaser and se
23、ller, but, in the absence of such agreement,the total thickness shall be 2 6 0.2 mils (50 6 5 m).8.1.7 In instances where clear coatings are to be tested, theymay be applied to aluminum or white carrara glass, one side ofwhich has been polished to a smooth, high-gloss finish. Otherselected substrata
24、 previously agreed upon between the pur-chaser and the seller may also be used. In the absence of aspecific agreement between the purchaser and the seller inregard to film thickness, apply the coatings by automatic spray.(Refer to Practices D823, Method A) at a dry film thickness of2 6 0.2 mils (50
25、6 5 m). Multiple coats may be used to obtainthis film thickness where necessary due to the nature of thecoating material (Note 1). Manual spray application or thedrawdown method with wire-wound draw bars may be usedwhen automatic equipment is not available.NOTE 1Dry film thickness should be measured
26、 in accordance withTest Method D1005 or Practice D7091, whichever is applicable. Theadhesion, flexibility, and color can vary considerably with thickness.8.2 Baking:8.2.1 The baking schedule for each coating includingprimer, topcoat, and primer/topcoat systems shall be mutuallyagreed upon between th
27、e purchaser and the seller and shallinclude the following:8.2.1.1 Normal Baking Schedule (Time and Temperature)recommended for the development of optimum film properties,and8.2.1.2 Overbaking CycleThis cycle shall be within prac-tical limits in order to simulate conditions that might beencountered i
28、n actual production where baking oven or con-veyor lines, or both might malfunction temporarily due tomechanical or electrical failure.8.3 Prepare four panels of each coating or coating systemand bake them at the schedule normally recommended toobtain optimum properties. Conduct the baking of these
29、panelsin a mechanical recirculating air oven set to 62C of thespecified baking temperature. At the end of the specified timeremove two panels from the oven and subject the remainingtwo to the overbake cycle by:8.3.1 A continuation of the normal bake but for a previouslyagreed upon time, for example,
30、 50 or 100 % increase in time,or8.3.2 Resetting the oven temperature to the agreed overbaketemperature and then continuing the bake for a specified periodof time after the overbake temperature has been reached, orremoving the panels until the overbake temperature is reachedand then baking them for t
31、he agreed upon time.NOTE 2The conditions described in 8.3.2 are not usually reproduciblebetween laboratories or different ovens because of variations in theheating characteristics of ovens.8.3.3 After the sets of panels have been baked according tothe mutually agreed upon baking cycles, place them i
32、n asuitable rack and condition for 24 h at 23 6 2C and 50 6 5%relative humidity (see Test Methods D1640) prior to testing.Other conditioning terms may be agreed upon between thepurchaser and the seller.9. Test Methods9.1 Determine the properties of both sets of panels inaccordance with any or all of
33、 the following ASTM methods:9.1.1 GlossTest Method D523.9.1.2 ColorPractice D1729 (Visual), Practice E805(instrumental), or Practice D2244.9.1.3 FlexibilityTest Methods D522 (conical mandrel andcylindrical mandrel).9.1.3.1 Heat-aged flexibility values should be determined inaccordance with a baking
34、cycle that is in agreement betweenthe purchaser and the seller.9.1.4 AdhesionTest Methods D21973(mechanical) orD3359 (tape), or both.3This test method has been found to be inapplicable for powder coatings.D2454 1429.1.5 Impact ResistanceTest Method D2794.49.1.6 HardnessTest Method D3363 (pencil test
35、).9.1.7 Exposure to ReagentsIf this test is desired, thechoice of materials to which the coating is to be exposed shallbe governed by the ultimate use of the coating and shall beagreed upon between the purchaser and the seller. The generalprocedure to be followed in this test is given in Test Method
36、D1308.9.1.8 Other tests agreed upon between the purchaser and theseller.10. Report10.1 Report the following information:10.1.1 Substrate employed, including type and thickness,10.1.2 Type of coating,10.1.3 Film thickness, including primer, if any,10.1.4 Normal bake schedule, or schedules,10.1.5 Over
37、bake cycle,10.1.6 Test methods employed, and10.1.7 Values determined, including the measured changesbetween the normal and overbake cycles.11. Keywords11.1 effect of overbake; organic coatings; overbakeSUMMARY OF CHANGESCommittee D01 has identified the location of selected changes to this standard s
38、ince the last issue (D245408)that may impact the use of this standard. (Approved February 1, 2014.)(1) Deleted D1400 and D2092 from Section 2.(2) Added D6386 and D7396 to Section 2.(3) Added keywords.ASTM International takes no position respecting the validity of any patent rights asserted in connec
39、tion 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.This standard is subject to revision at any time by the responsib
40、le 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 International Headquarters. Your comments will receive careful con
41、sideration 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
42、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/).4It is suggested that impact resistance be determined by use of the GardnerVariable Impact Tester obtainable from the Gardner Laboratory, Inc., Bethesda, MD.D2454 143
