ASTM D5043-2004 Standard Practice for Field Identification of Coatings《涂层现场识别的标准规程》.pdf

1、Designation: D 5043 04Standard Practice forField Identification of Coatings1This standard is issued under the fixed designation D 5043; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenthe

2、ses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes procedures and portable appara-tus for determining the generic type of coating films mostlikely to be encountered on structures.

3、 The coating can eitherbe weathered from exposure or be freshly applied.1.2 Most commonly used coatings can be divided into thebroad categories and subgroups shown in Table 1 on the basisof the nonvolatile component (generic types) of their vehicle(film forming resin, binder). Although the curing of

4、 somecoatings involves more than one process and coatings maycontain more than one type of resin, they can usually beassigned to one of the basic classes and generic types listed inTable 1.1.3 For field exposed coatings, it is suggested that these testmethods be used as part of a complete evaluation

5、 of a coatedsurface as it is frequently helpful to consider the environmentof exposure and how the coating has performed in theenvironment when drawing conclusions from these tests.1.4 These procedures will not result in the identification ofcomponents of a coating beyond general classification of t

6、hecoating by generic type and are not appropriate if more detailedanalysis is required, for example, as a part of failure analysis orto identify between different manufacturers of the same type ofcoating. They also may not be definitive enough to identifycomplex systems that include multiple layers

7、of differentgeneric types of coatings.1.5 The evaluation of results is quite subjective. Practiceand experience are required to minimize misinterpretation.Repeat tests may be required.1.6 None of the test is to be taken alone as grounds foridentifying the generic type. Only the combination of result

8、sfrom several or all of the tests is to be used in conclusionsregarding generic types.1.7 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for in formationonly.1.8 This standard does not purport to address all of thesafety concerns, if any, associa

9、ted with its 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. For specific hazardstatements see 5.3.4, 6.3.1, 6.3.3, 7.4, and 8.4.2. Summary of Practice2.1 Samples

10、of coatings films are tested with solvents andchemicals and subjected to pyrolysis to provide evidence oftheir generic type. Fig. 1 shows a flow chart for suggested orderof tests and classification of results.3. Significance and Use3.1 Information about the generic type of coating on asurface is req

11、uired to select compatible coatings for repaintingand can be used when evaluating the performance of a coatingin an environment in decisions on upgrading or replacing acoating system. This guide provides a systematic procedure foridentifying the generic type of a coating. The procedure can beperform

12、ed in the field by personnel with limited laboratoryexperience, and requires a minimum of equipment and mate-rials.4. Sampling4.1 The sample of coating is obtained by chipping orscraping with a knife or by sanding and then brushing thematerial into a specimen container or clean envelope. Careshould

13、be taken not to cut into substrates, such as plastic orasphalt, that contain polymeric or bituminous materials. Smallportions of untreated wood, masonry, or steel do not ordinarilyinterfere with the tests. Some tests can be conducted directly onthe coating surface. If a liquid sample of coating is t

14、o beevaluated, a film of the coating should first be cast on a glassplate or similar surface from which it can conveniently beremoved after drying.NOTE 1To develop familiarity with the subjective evaluations thatfollow, it is good practice to make films of known resin composition byapplying control

15、paints to glass plates or similar surfaces from which theycan be readily removed after drying.5. Pyrolysis5.1 Summary of Test ProcedureA sample of coatingplaced in a small glass test tube is burned over a hot flame. Theway the coating burns, its odor, and other characteristics of thefume generated a

16、re recorded. The Beilstein test identifies thepresence of chlorinated and other halogens. In coatings,1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.46 on Industrial Protecti

17、ve Coatings.Current edition approved Nov. 1, 2004. Published November 2004. Originallyapproved in 1990. Discontinued November 1997 and reinstated in 2004 asD 5043 - 04.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.chlorine-containi

18、ng material is most often encountered. Forcoatings not containing halogens, the odor is recorded.5.2 Apparatus:5.2.1 Flame Source, including butane or propane utilitytorch. (Lighters do not provide a hot enough flame.)5.2.2 Glass Test TubesA suitable size is 10 by 75 mm(disposable culture tubes).5.2

19、.3 Copper Wire, a length of single-strand 16 to 18 gage.AWG copper electrical wire, stripped of insulation sufficientlyfar that melted insulation cannot interfere with the test, issatisfactory. Leave about 6 in. of insulation as a heat insulatoror provide a wrapping or handle for protection from hea

20、t.5.2.4 Lead Acetate Paper.5.2.5 Test Tube Clamp.5.3 Procedure:5.3.1 Put a small specimen of coating, preferably of onetype, in the test tube. Hold the tube briefly in the hot flame.Limit flame contact to the end of the test tube immediatelyaround the specimen. As the specimen is heated, observe the

21、nature of deterioration and identify coating type as follows:Observation IdentificationNo change in shape; possible change in color;continued heating causes sample to glow redInorganicRapid deterioration, almost explosive in nature Cellulose nitrate or similarSwelling Some vinyl-type coatingsNOTE 2M

22、elting, bubbling, and charring are common with mostgeneric types and not definitive.5.3.2 Continue heating until fume (smoke) fills the test tube.Most fumes are white or near-white; slight condensation of aclear liquid on the upper test tube wall is sometimes observed.Other observations and identifi

23、cations include:Observation IdentificationDark fume; clear brown liquid condensate Possibly epoxyVery dark, possibly sooty fume; dark condensate BituminousNOTE 3Bituminous coatings may be asphalt, coal tar, or combina-tions. The test is not definitive.NOTE 4Silicone coatings will form an ash upon py

24、rolysis at 800C.Such temperatures are outside the scope of this test.5.3.3 Beilstein TestConduct the Beilstein test by firstheating the bare copper wire in the flame until no color isimparted to the flame. Insert the heated wire into hot fume inthe test tube briefly (1 to 2 s). Withdraw the copper w

25、ire fromthe test tube and immediately hold it in the flame again.Observe the flame over the copper wire for color and makeidentifications as follows:Observation IdentificationNo color No chloride (or other halogen) contentTraces of green color Chloride contaminants from environment orminor component

26、 of coatingStrong green color Chlorinated resin or chlorinated resin modifierWith practice the intensity of the green flame can be used todetermine whether the chlorine containing component is majoror minor.5.3.3.1 Example 1A very intense, relatively long-lastingrepeatable green flame indicates chlo

27、rinated rubber or vinylcoating.5.3.3.2 Example 2An intense or moderately intense rela-tively short-lived green flame, which may or may not berepeated, indicates chlorinated plasticizer in a nonchlorinatedresin binder.NOTE 5Although fluorinated resins also give a positive Beilstein test,they are less

28、 likely to be encountered in the industrial applications thanchlorinated resins.NOTE 6If the sample includes hydrated material, for example, con-crete or plaster, water will be liberated by burning and will condense onthe wall of the test tube. Halogen liberated from the paint will be absorbedinto t

29、he condensate. The copper wire must be brought into contact with thecondensate to avoid a false negative.NOTE 7Those experienced with the Beilstein test may prefer to run iton a specimen not subjected to pyrolysis.5.3.4 Odor TestConduct the odor test only if the Beilsteintest is negative (no green f

30、lame). Tip the test tube so that thefumes flow toward the open end of the tube. Gently wave ahand over the mouth of the test tube and carefully smell theodor of the fumes as they dissipate from the mouth of the testtube. (WarningHot chlorine or fluorine-containing vaporsand gases are extremely irrit

31、ating and potentially hazardous. Inaddition, coatings may contain lead or other toxic metals thatvolatilize and form metal fumes during this test procedure.Care must be taken to avoid inhalation of the vapors, gases andfumes.)5.3.4.1 Indications are subjective, but the following classescan be assign

32、ed:Observation IdentificationOily OleoresinousVery sweet Acrylic latexVinegary; acetic acid Poly (vinyl acetate)Burning hair Epoxy, epoxy ester, bituminous epoxyBurning rubber PolysulfideNo strong odor Inorganic, cementitousAcrid (biting) odor with sooty ortarry smokeBituminous5.3.5 Use the lead ace

33、tate paper to verify the presence of asulfide component by holding a piece of moistened lead acetatepaper over or in the mouth of the test tube. A sulfur-containingcomponent is present if the paper rapidly darkens.6. Solubility Tests6.1 Chemically cured, inorganic, and aged oleoresinouscoatings are

34、not resoluble in the solvents originally used inproducing the coatings. Lacquers and some latex coatings areTABLE 1 Classification of Coatings Frequently UsedBasic Class ExamplesAir-drying or baking (oxidizing)paint and enamelUnmodified drying oilOleoresinous (oil-modified, alkyd, epoxyester, phenol

35、ic and other resins)Lacquer (drying by evaporationof water)Vinyl (polyvinyl chloride-vinyl acetate)Poly(vinyl butyral)Chlorinated rubberStyrene-butadiene rubber and similarrubbersBituminous (coal, tar, asphalt)Cellulose nitrateLatex (drying by evaporationof water)Poly(vinyl acetate)AcrylicStyrenated

36、 acrylicChemically curing single packageand multi-component coatingEpoxyBituminous epoxyUrethanePolyesterInorganic Silicates and cementMiscellaneous Flame-sprayedSiliconesD5043042resoluble and the strength of the solvent required to cause thecoating to dissolve can be used to classify the coating.6.

37、2 ReagentsSolvents used, listed in order of increasingpower of solvency (that is, ability to dissolve a resin), are asfollows:6.2.1 Denatured Alcohol (Ethyl Alcohol).6.2.2 Mineral Spirits (Petroleum Spirits), aliphatic hydro-carbon solvent with typical Kauri-Butanol value (KB) of 25 to45.6.2.3 Xylen

38、e (Xylol), aromatic hydrocarbon solvent withtypical KB of 98.6.2.4 Methyl Isobutyl Ketone (MIBK, 4-Methyl-2-Pentanone).6.2.5 Acetone (Dimethyl Ketone, 2-Propanone).6.3 Procedure:6.3.1 Use a stirring rod or a gloved fingertip to conduct therub test. The test is perhaps best done by a finger-rub techn

39、iqueon the coating film itself because the sensations perceptible bytouch are valuable in interpreting results. Alternatively, thesolubility tests may be done by soaking portions of the film insolvents, in which case porcelain spot plates and glass stirringrods can be used. (WarningThese solvents ca

40、n cause skinirritation and dermatitis. Minimize time of contact of solventswith skin and discontinue use if irritation occurs.)6.3.2 Rub TestBeginning with ethanol, dampen a fingertipor glass rod and rub the surface of the film briskly in a circularmotion 5 to 10 mm (14 to12 in.) in diameter. Renew

41、the testsolvent frequently as required. Continue rubbing at least 30 s oruntil definite effects are observed. Continue with each solventin increasing power of solvency. Cleaning the fingertip or glassrod in each succeeding solvent before using that test solvent.Select a new spot on the film or an un

42、tested chip of paint foreach solvent used.NOTE 8If the coating film on the test surface is chalky, the firstfinger-rub test done with ethanol will liberate much of the chalk, whichwill dry quickly as a powder. Repeating the test will reveal much less orno color and the test surface will appear uncha

43、nged. If chalk is liberated,use ethanol to clean the test spot for subsequent solvent tests.6.3.3 Solvent-Soak TestThe full series of solvents can berun concurrently. Place five chips in a spot plate dish and poura small amount of each solvent over one of the chips.Periodically stir the solvent and

44、rub the chip with a glassstirring rod until definite changes occur. Add additional sol-vent, if necessary due to evaporation, and observe extent ofdiscoloration of the solvent and whether the chip softens,breaks apart, swells, dissolves, or a combination thereof. Notewhether a color different from t

45、he color of the topcoat isimparted to the solvent, indicating dissolution of an interme-diate or primer coat. If portions of the chip dissolve or discolorthe solvent, soak up the solvent with a paper towel and addfresh solvent if undissolved chip remains. If no further effectoccurs, wash the remaind

46、er of the chip by gentle swirling, soakup the solvent, allow the chip to dry, and proceed withpyrolysis or other tests. (WarningDo not attempt to burn asolvent-wet chip or heat solvent in a test tube, as the liquid maysuddenly boil, possibly causing burns or loss of specimen.)6.3.4 Observe the effec

47、ts of rubbing or soaking and classifyas follows (the results for the soaking test are more difficult tointerpret than for the rub test):FIG. 1 Suggested Test Flow Chart for Coatings IdentificationD50430436.3.4.1 No effect or small amount of color transfer to thefingertip or rod (due to chalk or film

48、 surface abrasion whilerubbing).6.3.4.2 Softening of the film, with resin rolling into smallballs under the fingertip or rod.6.3.4.3 True solubility with film dissolving, becomingsticky, and transferring in relatively large liquefied quantity tothe fingertip or rod.6.3.5 Succeeding layers in a coati

49、ng system may be indi-vidually tested if they are visually different; for example,colored topcoat, white or gray intermediate coat, and brown orred primer coat. To test visually different layers, repeatedly rubthe spot with an effective solvent and wipe away dissolvedcoating periodically until a sub layer of different color is clean,then continue the test with the effective solvent on the sublayer. If that solvent is ineffective, repeat the test on the samespot with the next stronger solvent in the series. If that solventis effective, repeat the test on a new spe