1、Designation: D2454 14D2454 18Standard 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
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. Scope*1.1 This practice covers the determination of the time-temperature effect of overbaking on the physical and chemical propertie
3、sof organic coatings.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof whoever uses this s
4、tandard to consult and establish appropriate safety safety, health, and healthenvironmental practices anddetermine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 7.1.4 This international standard was developed in accordance with internationa
5、lly recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D522 Test Meth
6、ods for Mandrel Bend Test of Attached Organic CoatingsD523 Test Method for Specular GlossD609 Practice for Preparation of Cold-Rolled Steel Panels for Testing Paint, Varnish, Conversion Coatings, and Related CoatingProductsD823 Practices for Producing Films of Uniform Thickness of Paint, Coatings an
7、d Related Products on Test PanelsD1005 Test Method for Measurement of Dry-Film Thickness of Organic Coatings Using MicrometersD1308 Test Method for Effect of Household Chemicals on Clear and Pigmented Organic FinishesD1640 Test Methods for Drying, Curing, or Film Formation of Organic CoatingsD1729 P
8、ractice for Visual Appraisal of Colors and Color Differences of Diffusely-Illuminated Opaque MaterialsD1730 Practices for Preparation of Aluminum and Aluminum-Alloy Surfaces for PaintingD1731 Practices for Preparation of Hot-Dip Aluminum Surfaces for PaintingD2197 Test Method for Adhesion of Organic
9、 Coatings by Scrape AdhesionD2201 Practice for Preparation of Zinc-Coated and Zinc-Alloy-Coated Steel Panels for Testing Paint and Related CoatingProductsD2244 Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color CoordinatesD2794 Test Method for Resis
10、tance of Organic Coatings to the Effects of Rapid Deformation (Impact)D3359 Test Methods for Rating Adhesion by Tape TestD3363 Test Method for Film Hardness by Pencil TestD6386 Practice for Preparation of Zinc (Hot-Dip Galvanized) Coated Iron and Steel Product and Hardware Surfaces for PaintingD7091
11、 Practice for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic Coatings Applied to Ferrous Metalsand Nonmagnetic, Nonconductive Coatings Applied to Non-Ferrous MetalsD7396 Guide for Preparation of New, Continuous Zinc-Coated (Galvanized) Steel Surfaces for PaintingE805 Practice for Id
12、entification of Instrumental Methods of Color or Color-Difference Measurement of Materials3. Terminology3.1 Definitions:1 This practice is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.27 on
13、 Accelerated Testing.Current edition approved Feb. 1, 2014July 1, 2018. Published March 2014July 2018. Originally approved in 1966. Last previous edition approved in 20082014 asD2454 08.D2454 14. DOI: 10.1520/D2454-14.10.1520/D2454-18.2 For referencedASTM standards, visit theASTM website, www.astm.o
14、rg, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standardsstandards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of w
15、hat changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered t
16、he official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.1 overbaking, nan exposure of the coating to a moderately higher temperature or to a longer peri
17、od of baking, or both,than recommended by the manufacturer of the coating for normal curing.3.1.1.1 DiscussionThis condition is in contrast to “heat resistance” which is a parameter relating to the service life of a coating.4. Summary of Practice4.1 Four panels are prepared and baked at the schedule
18、 normally recommended for the coating. Two of the panels are thenremoved and the remaining two are subjected to an additional overbake in which the time and temperature are mutually agreedupon between the purchaser and the seller. The sets of panels, after a suitable conditioning interval, are then
19、evaluated for theproperties that are compatible with the substrate. Among these are gloss, color, flexibility, adhesion, impact resistance, andresistance to reagents. Note that glass substrates should not be tested for impact, and zinc-coated substrates can influence bothflexibility and impact.NOTE
20、1Glass substrates should not be tested for impact, and zinc-coated substrates can influence both flexibility and impact.5. Significance and Use5.1 Most coatings are designed for a specific baking time and temperature. For a variety of reasons (line stoppages, reroutingback through ovens, oven overhe
21、ating, etc.) the prescribed time or temperature, or both, of the bake is often exceeded. This practicehas been found to be useful in evaluating the effects of overbakes on coatings.6. Materials6.1 Standard Baking-Type Coating mutually agreed upon between the purchaser and the seller.7. Hazards7.1 Th
22、e flash points of most solvents used in many organic coatings and related products are low enough that adequateventilation is needed to avoid exceeding 25 % of the lower explosive limits of the solvents when test panels are being preparedand baked. As these materials are considered toxic, take care
23、to avoid inhalation of solvent vapor and unnecessary contact ofsolvent with the skin.8. Procedure8.1 Application of Organic Coating:8.1.1 Apply coatings to steel panels prepared in accordance with Practice D609.8.1.2 Apply coatings to zinc-coated surfaces prepared in accordance with Guide D7396 or P
24、ractice D6386, when zinc has beenapplied by the hot-dip method or by electroplating.8.1.3 Apply coatings to nonpassivated galvanized steel prepared in accordance with Guide D7396 Practice D2201, when thezinc is applied by a continuous galvanizing method using an aluminum-bearing zinc.8.1.4 Apply coa
25、tings to aluminum surfaces on all-aluminum materials prepared in accordance with Practices D1730.8.1.5 Apply coatings to hot-dip aluminum coated surfaces prepared in accordance with Practices D1731.8.1.6 In cases where a primer is used in practice under the topcoat, apply the entire system to the pa
26、nels. The film thicknessof each coat shall be mutually agreed upon between the purchaser and seller, but, in the absence of such agreement, the totalthickness shall be 2 6 0.2 mils (50 6 5 m).8.1.7 In instances where clear coatings are to be tested, they may be applied to aluminum or white carrara g
27、lass, one side ofwhich has been polished to a smooth, high-gloss finish. Other selected substrata previously agreed upon between the purchaser andthe seller may also be used. In the absence of a specific agreement between the purchaser and the seller in regard to film thickness,apply the coatings by
28、 automatic spray. (Refer to Practices D823, Method A) at a dry film thickness of 2 6 0.2 mils (50 6 5 m).Multiple coats may be used to obtain this film thickness where necessary due to the nature of the coating material (Note 12).Manual spray application or the drawdown method with wire-wound draw b
29、ars may be used when automatic equipment is notavailable.NOTE 2Dry film thickness should be measured in accordance with Test Method D1005 or Practice D7091, whichever is applicable. The adhesion,flexibility, and color can vary considerably with thickness.8.2 Baking:8.2.1 The baking schedule for each
30、 coating including primer, topcoat, and primer/topcoat systems shall be mutually agreed uponbetween the purchaser and the seller and shall include 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 Cyc
31、leThis cycle shall be within practical limits in order to simulate conditions that might be encounteredin actual production where baking oven or conveyor lines, or both might malfunction temporarily due to mechanical or electricalfailure.D2454 1828.3 Prepare four panels of each coating or coating sy
32、stem and bake them at the schedule normally recommended to obtainoptimum properties. Conduct the baking of these panels in a mechanical recirculating air oven set to 62C of the specified bakingtemperature.At the end of the specified time remove two panels from the oven and subject the remaining two
33、to the overbake cycleby:8.3.1 A continuation of the normal bake but for a previously agreed upon time, for example, 50 or 100 % increase in time, or8.3.2 Resetting the oven temperature to the agreed overbake temperature and then continuing the bake for a specified periodof time after the overbake te
34、mperature has been reached, or removing the panels until the overbake temperature is reached and thenbaking them for the agreed upon time.NOTE 3The conditions described in 8.3.2 are not usually reproducible between laboratories or different ovens because of variations in the heatingcharacteristics o
35、f ovens.8.3.3 After the sets of panels have been baked according to the mutually agreed upon baking cycles, place them in a suitablerack and condition for 24 h at 23 6 2C and 50 6 5 % relative humidity (see Test Methods D1640) prior to testing. Otherconditioning terms may be agreed upon between the
36、purchaser and the seller.9. Test Methods9.1 Determine the properties of both sets of panels in accordance with any or all of 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 (
37、conical mandrel and cylindrical mandrel).9.1.3.1 Heat-aged flexibility values should be determined in accordance with a baking cycle that is in agreement between thepurchaser and the seller.9.1.4 AdhesionTest Methods D21973 (mechanical) or D3359 (tape), or both.9.1.5 Impact ResistanceTest Method D27
38、94.49.1.6 HardnessTest Method D3363 (pencil test).9.1.7 Exposure to ReagentsIf this test is desired, the choice of materials to which the coating is to be exposed shall begoverned by the ultimate use of the coating and shall be agreed upon between the purchaser and the seller. The general proceduret
39、o be followed in this test is given in Test Method D1308.9.1.8 Other tests agreed upon between the purchaser and the seller.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,1
40、0.1.4 Normal bake schedule, or schedules,10.1.5 Overbake cycle,10.1.6 Test methods employed, and10.1.7 Values determined, including the measured changes between the normal and overbake cycles.11. Keywords11.1 effect of overbake; organic coatings; overbakeSUMMARY OF CHANGESCommittee D01 has identifie
41、d the location of selected changes to this standard since the last issue(D245408)14) that may impact the use of this standard. (Approved FebruaryJuly 1, 2014.)2018.)(1) Deleted D1400 and D2092 from Section 2.Removed last sentence in Section 4.1 and made as a note.(2) Added D6386 and D7396 to Section
42、 2.Renumbered remaining notes.(3) Added keywords.3 This test method has been found to be inapplicable for powder coatings.4 It is suggested that impact resistance be determined by use of the Gardner Variable Impact Tester obtainable from the Gardner Laboratory, Inc., Bethesda, MD.D2454 183ASTM Inter
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