1、Designation: C756 87 (Reapproved 2011)1Standard Test Method forCleanability of Surface Finishes1This standard is issued under the fixed designation C756; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTETest Method was corrected editorially in 2011INTRODUCTIONThis test provides a procedure to quantify the cleanability of acid-resistant porcela
3、in enamel usinga fluorescent water-soluble soil in agent, a reproducible machine-wiping technique, and a means ofmeasuring the amount of residual soil by fluorescence.1. Scope1.1 This test method covers the numerical evaluation of theease or difficulty of cleaning soiled surface finishes. This testm
4、ethod is applicable to all surface finishes not affected bywater.1.2 Values given in SI units are to be regarded as thestandard. Inch-pound units are provided for information only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is therespo
5、nsibility 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.2. Referenced Documents2.1 ASTM Standards:2C282 Test Method for Acid Resistance of Porcelain Enam-els(Citric Acid Spot Test)C614 Test M
6、ethod forAlkali Resistance of Porcelain Enam-els3. Summary of Test Method3.1 The test method consists of applying an exact amount ofa fluorescent water-soluble soiling agent to a specimen surfaceand then cleaning the surface with a reproducible machine-wiping technique. The soil remaining on the spe
7、cimen afterwiping is extracted with a water solvent and the fluorescence ofthe solution measured. A standard reference surface is treatedin a similar manner. The cleanability index of the surface undertest is expressed as the ratio of the fluorescence of the solutionsextracted from the test surface
8、and from the standard referencesurface. Cleanability indexes greater than 1.0 indicate that thetest surface is more difficult to clean than the standardreference surface, while indexes less than 1.0 indicate that thetest surface is more easily cleanable than the standard ofcomparison.3.2 The soiling
9、 agent used consists of polyethylene glycol,a black dye, and a fluorescent tracer, each of which is readilywater soluble.4. Significance and Use4.1 This test method was developed to guide the user inselecting a finish coating or material that is resistant to soilingin a particular application.4.2 Th
10、e numerical values derived by this test methodenables the user to rank finish coatings and materials in regardto soil retention or ease of soil removal.5. Apparatus5.1 Motor-Driven Lapping Plate, 203-mm (8-in.) diameter,speed 163 r/min.35.2 Automatic Polishing Unit, 11-s cycle, adjustable to48-mm (1
11、78-in.) stroke.45.3 Hypodermic Syringe, glass, 2-mL capacity, withoutneedle.5.4 Repeating Pipet, 0.025 mL (25 l) capacity.5.5 Repeating Pipet, 10-mL capacity.1This test method is under the jurisdiction ofASTM Committee B08 on Metallicand Inorganic Coatings and is the direct responsibility of Subcomm
12、ittee B08.12 onMaterials for Porcelain Enamel and Ceramic-Metal Systems.Current edition approved April 1, 2011. Published April 2011. Originallyapproved in 1973. Last previous edition approved in 2006 as C756 87 (2006).DOI: 10.1520/C0756-87R11E01.2For referenced ASTM standards, visit the ASTM websit
13、e, 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.3Suitable lapping plates are available from Buehler Ltd., 2120 Greenwood St.,Evanston, IL 60204, Struers, Inc., 20
14、102 Progress Drive, Cleveland, OH, 44136; orother Metallurgical Supply Sources.4An Olsen “S.M.” Automatic Polisher has been found suitable and is availableunder the code name OLPOL from Struers, Inc., 20102 Progress Drive, Cleveland,OH 44136.1Copyright ASTM International, 100 Barr Harbor Drive, PO B
15、ox C700, West Conshohocken, PA 19428-2959, United States.5.6 Desiccator approximately 254 mm (10 in.) diameter.5.7 Cleaning Head, brass, 57 mm (214 in.), with worm-driven hose clamp for attachment of cleaning tissues (Fig. 1).5.8 Soiling Head, brass, 25 mm (1 in.) diameter, with25-mm (1-in.) diamete
16、r facing of polytetrafluoroethylene at-tached with a water-proof household cement (Fig. 1).5.9 Extraction Cell, fitted with a fluorosilicone O-ring, size3.2 by 57 mm (18 by 214 in.) (Fig. 2).55.10 Fluorometer, for measuring the fluorescence of solu-tions.65.11 0.9 Neutral Density Filter, 50.8 by 50.
17、8 mm (2 by 2in.) glass mounted (transmission 12.5 %).5.12 Beakers, borosilicate, 100-mL capacity.6. Reagents and Materials6.1 Cleaning Tissues, approximately 127 by 229 mm (5 by9 in.).76.2 Potassium Carbonate.6.3 Polyethylene Glycol, 400.6.4 Uranine, water-soluble, USP.86.5 Keco Acid Black, B(F101).
18、96.6 Ethyl Alcohol.6.7 Mild Household Detergent, liquid.7. Test Specimens7.1 The preferred specimen size is 114 mm (412 in.) square,but any other size or shape may be used provided it can berotated on the lapping wheel and the smaller dimension isbetween 102 and 127 mm (4 and 5 in.). Sharp or jagged
19、 edgesshall be filed or honed to prevent snagging of the cleaningtissues during the mechanical cleaning process.7.2 Twelve specimens are required to evaluate the cleanabil-ity index, that is, six of the candidate surface, and six of aporcelain enamel standard reference surface for cleanability.Porce
20、lain enamel specimens are not damaged by the cleanabil-ity test and may be cleaned and reused many times. Specimenshave been reused as many as 50 times without damage or solidbuildup.NOTE 1The porcelain enamel covercoat used to coat the standardreference surface shall have the following characterist
21、ics: Acid Resis-tance: AA (Test Method C282) Alkali Resistance: Maximum 1.55 mg/cmwt. loss (Test Method C614).5O-rings must be fluorosilicone polymer; consult Precision Associates, 742 N.Washington Ave., Minneapolis, MN 55401; Parker Seal Co., 10567 W. JeffersonBlvd., Culver City, CA 90230; availabl
22、efrom Keystone Aniline and Chemical Co., 321 N. Loomis, Chicago, IL 60607.Cleaning Head, Brass Soiling Head, BrassMetric EquivalentsAB C D E F G Hin. 2145878316 15834316(mm) (57) (16) (22) (5) (25) (16) (19) (5)FIG. 1 Cleaning and Soiling HeadsC756 87 (2011)128. Preparation of Standard Soil8.1 The s
23、oiling agent shall consist of the following:Ingredient Weight %Polyethylene glycol 98Keco Acid Black B 1Uranine, water-soluble 18.2 The uranine shall be added to the polyethylene glycol infood blender and mixed by alternate periods of mixing andstanding until the crystalline uranine appears to be co
24、mpletelydissolved in the glycol. The black dye which obscures all elseshall be added last and thoroughly mixed in the blender. Thissoiling agent shall be stored in a tightly stoppered glass bottleat least overnight before use.9. Procedure9.1 Specimen PretreatmentScrub the specimens with acellulose s
25、ponge wet with a 1 % solution of a mild householddetergent at room temperature. Rinse in turn with tap water,distilled water, and ethyl alcohol, and allow to dry in anear-vertical position at room temperature. Store the washedand dried specimens overnight in a desiccator charged with asaturated solu
26、tion of potassium carbonate.9.2 Conditioning of Cleaning TissuesCut a supply oftissues ample for use in specimen cleaning treatment in thefollowing paragraph into approximately 102-mm (4-in.)squares and store overnight, before use, in a desiccator chargedwith a saturated solution of potassium carbon
27、ate (relativehumidity approximately 45 %). Allow the tissues to remain inthe desiccator until just prior to use.9.3 Soiling and Cleaning Treatments:9.3.1 Lay out six specimens face up on a table. Homogenizethe soiling agent by up-ending several times before use. Fill thehypodermic syringe with no ne
28、edle attached with the soilingagent by withdrawing the plunger. Expel this charge of soilback into the soil bottle. Then fill the syringe again. Wipe thetip of the syringe with a cleaning tissue and expel several dropsinto the soil bottle. Then, without rewiping the tip, hold thesyringe vertically o
29、ver a specimen and discharge one drop nearthe center of each of the six specimens. Center the firstspecimen on the lapping wheel and hold it in place by meansof adhesive tape across the specimen corners. Place thepolytetrafluoroethylene-faced soiling head on the soil, andengage the spindle (Fig. 4)
30、of the polishing unit. Operate thelapping wheel and the polishing unit for 1 min to distribute thesoil over the central portion of the specimen (Fig. 5). Removethe soiling head and clean it with tissue for reuse. Adjust thespindle so that it rests over the center of the soil spot. Preparetwo cleanin
31、g heads 57 mm (214 in.) diameter) by covering withMetric EquivalentsABCDEFGHIin.11618164 212 11458116 178 218(mm.) (1.6) (3.2) (0.4) (64) (32) (16) (1.6) (47) (54)All surfaces to be plated with bright nickel.FIG. 2 Brass Extraction CellC756 87 (2011)13four thicknesses of cleaning tissues clamped smo
32、othly in place.With the repeating pipet expel exactly 0.021 mL of distilledwater at the center of the tissue on the first cleaning head.9.3.2 Immediately place the cleaning head with tissue sideagainst the soiled specimen, engage the spindle, and operate for22 s (so that it will stop as well as star
33、t at the center of thespecimen). Remove the cleaning head without sliding motion.Repeat the cleaning operation with the second tissue-coveredhead, using the same amount of distilled water and for the same22-s period.9.3.3 Store the first soiled and cleaned specimen in a nearvertical position in a ra
34、ck while applying exactly the sameseries of soiling and cleaning treatments to the five remainingspecimens.9.4 Water Extraction of the Soil RetainedRemove thesmall, often nonvisible, amounts of soil from the centralportion of the soiled and cleaned specimens with 10 mL ofdistilled water in the O-rin
35、g sealed extraction cell by thefollowing sequence of operations within 30 min after soiling;place the first soiled and cleaned specimen, face up, in thecenter of the cell clamping frame. Place a clean and dryextraction cell (Fig. 2) on the center of the specimen so that theO-ring defines the area to
36、 be extracted (Fig. 5). Clamp the cellin the frame with a light pressure from the wing nuts; introduce10 mL of distilled water with the 10-mL repeating pipet, swirlthe water in the cell momentarily and let stand for 3 min, givethe solution in the cell another swirl and pour out into a cleanand dry 1
37、00 mL beaker; transfer a portion of the extract to aclean, dry cuvette and place the cuvette in a rack until the otherfive extracts are ready for measurement in the fluorometer.9.5 Measurement of FluorescenceOperate the fluorometeraccording to the manufacturers instructions. Measure andrecord the fl
38、uorescence of a distilled water blank. Measure andrecord in turn the fluorescence of the solutions extracted fromthe specimens.NOTE 2If concentrated solutions give off-scale readings, a 0.9neutral-density filter should be inserted between the fluorescing solutionand the photomultiplier. This filter
39、transmits only 12.5 % of the lightemitted by the solution, reducing the fluroescence readings and bringingthem on scale. Redetermine the blank reading with the filter in place andmultiply the reduced reading by 8.0 which is 1 divided by the 12.5 %transmission of the neutral density filter.9.6 Standa
40、rd Reference SurfaceApply the test procedureoutlined in 7.1 through 7.5 to the Standard Reference Surfacesat least once during each testing day to obtain the averagefluorescence of solutions extracted from these specimens.Metric EquivalentsABCDEFGHI JKLMNin.116 214 13814 178516 56114 31414 458 458 5
41、(mm) (1.6) (64) (35) (6.4) (47) (8) (127) (152) (32) (83) (6.4) (117) (117) (127)FIG. 3 Device for Clamping Extraction Cell to SpecimenC756 87 (2011)149.7 Preferred Methods of Equipment Cleaning:9.7.1 The successful use of the fluorimetric analytical tech-niques employed in this procedure demands th
42、at a scrupulouslevel of cleanliness be maintained throughout. An oily thumb-print on the glass cuvette containing the solution to bemeasured may be more fluorescent than the unknown.Metric EquivalentsABCin. 101214(mm.) (254) (13) (6.4)FIG. 4 Spindle for PolisherFIG. 5 Equipment Used in Soiling and C
43、leaning SpecimensC756 87 (2011)159.7.2 Wash the glass beakers and the extraction cells beforeand after use by brushing in a warm detergent solution; rinsecopiously with flowing tap water and then with distilled water.The glass beakers may be oven dried. The extraction cells,without O-ring removal, m
44、ay be wiped dry with clean tissue.Clean the syringe used for dispensing uniform amounts of soilon the specimens immediately following use with tap water,distilled water and alcohol, and dry the parts with tissue. Givethe glass cuvettes used for measuring fluorescent solutionsseveral rinses with tap
45、water and then alcohol, and allow todrain in an inverted position in a holding rack. Discard thetissue for wiping glassware and other equipment after one use.10. Calculation of a Cleanability Index10.1 Subtract the measured fluorescence value for the dis-tilled water blank from the measured fluoresc
46、ence value foreach of the six test surfaces and the six standard referencesurfaces. This will result in corrected fluorescence values forthe six test surfaces and for the six standard reference surfaces.10.2 Calculate the average of the corrected fluorescencevalues for the six test surfaces and for
47、the six standardreference surfaces.10.3 Calculate the coefficient of variation of the correctedfluorescence values for the six test surfaces and for the sixstandard reference surfaces.10.4 Repeat the cleanability determinations on all six speci-mens (either the test specimens or the six standard ref
48、erencespecimens) if the coefficient of variation is greater than 20 %.10.5 The cleanability index is calculated as follows:CI 5 Ft/Fr (1)where:CI = the cleanability index of the surface being tested,Ft = the average corrected fluorescence of the test surfacesas calculated in 10.2, andFr = the averag
49、e corrected fluorescence of the standardreference surfaces as calculated in 10.3.10.6 The method of calculation is shown in the Appendixes.11. Precision and Bias11.1 The precision of this test method, when performed bythe same operator in the same laboratory, should be sufficientso that the cleanability determination on six standard refer-ences should show a coefficient of variation no greater than20 %. No standard is available by which the bias of the testmethod can be determined.APPENDIXES(Nonmandatory Information)X1. INITIA
