1、Designation: D 925 06Standard Test Methods forRubber PropertyStaining of Surfaces (Contact, Migration,and Diffusion)1This standard is issued under the fixed designation D 925; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r 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 These test methods cover techniques to evaluate threetypes of staining that rubber may cause when in contact wit
3、h,or in proximity to, another surface that may be light colored.1.2 The test methods also describe how to qualitativelyevaluate the degree of staining produced under the conditionsof exposure to heat alone or heat and light.1.3 The values stated in SI units are to be regarded as thestandard. The val
4、ues given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated 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 re
5、gulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1148 Test Method for Rubber DeteriorationHeat andUltraviolet Light Discoloration of Light-Colored SurfacesD 3182 Practice for RubberMaterials, Equipment, andProcedures for Mixing Standard Compounds and Prepar-ing Standard
6、 Vulcanized SheetsD 3183 Practice for RubberPreparation of Pieces for TestPurposes from ProductsE 145 Specification for Gravity-Convection And Forced-Ventilation OvensG 151 Practice for Exposing Nonmetallic Materials in Ac-celerated Test Devices that Use Laboratory Light SourcesG 154 Practice for Op
7、erating Fluorescent Light Apparatusfor UV Exposure of Nonmetallic MaterialsG 155 Practice for Operating Xenon Arc Light Apparatusfor Exposure of Non-Metallic Materials3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 stain, contactdiscoloration of a product by anothermaterial or
8、 product in the area of direct contact.3.1.1.1 DiscussionA test for direct surface discolorationof rubber is covered by Test Method D 1148.3.1.2 stain, diffusiondiscoloration of a light colored ve-neer or coating, caused by the diffusion of staining materialsfrom the rubber through the veneer or coa
9、ting.3.1.2.1 DiscussionThe veneer or coating is in directintimate contact with the underlying rubber.3.1.3 stain, migrationdiscoloration, caused by constitu-ents of a rubber, that occurs on any portion of the surface ofany object in the proximity of or adjacent to but not in directcontact with the r
10、ubber causing the stain.4. Summary of Test Methods4.1 The test methods are as follows:4.1.1 Method AContact Stain.4.1.2 Method BMigration Stain.4.1.3 Method CDiffusion Stain.4.2 Method ASpecimens to be tested for contact stainingare sandwiched between two metal panels. The metal panelsare furnished
11、with a desired light colored organic finish, whichis in contact with the rubber. The assembly is exposed toelevated temperatures for a specified length of time and thespecimens are then removed from the metal. The degree ofstaining of the surface that was in contact with the rubber israted against a
12、 reference standard and a control panel (a metalplate without rubber) which are simultaneously tested with thespecimen.4.3 Method BSpecimens to be tested for migration stain-ing are placed on a metal plate with a desired light coloredorganic finish, and exposed to either fluorescent UVA-340lamps or
13、filtered xenon arc radiation for a specified period oftime. The degree of staining beyond the area that was in contactwith the specimens is then rated against a reference standardand a control panel (a metal plate without rubber) which aresimultaneously tested with the specimen.4.4 Method CDiffusion
14、 staining is tested on specimensprovided with a light colored rubber veneer or organic coating,deposited from organic solvent or water base. The specimens1These test methods are under the jurisdiction of ASTM Committee D11 onRubber and are the direct responsibility of Subcommittee D11.15 on Degradat
15、ionTests.Current edition approved March 1, 2006. Published April 2006. Originallyapproved in 1947. Last previous edition approved in 2000 as D 925 88 (2000).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AS
16、TMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.are exposed to either fluorescent UVA-340 lamps or filteredxenon arc radiation, with thei
17、r veneer or coated side up, for aspecified period of time. Any staining of the light coloredveneer or organic coating is considered diffusion staining andrated against a reference standard and a control sample of theveneer or organic coating without the staining rubber.4.5 Specimens used in all thre
18、e staining tests shall includeone or more reference samples of known staining characteris-tics. In addition, the contact and migration staining tests shallinclude a metal panel, without rubber samples, to establish theeffect of the test conditions on the finished metal surface. Thediffusion staining
19、 test shall include, as controls, a vulcanizedsample of the rubber veneer by itself or a sample of the coatingapplied to aluminum foil.5. Significance and Use5.1 Rubber in contact with light colored organic finishesmay stain the surfaces in contact with the rubber (contactstaining) and surfaces adja
20、cent to or beyond the rubber(migration staining), especially under conditions of heat, pres-sure, or sunlight. When a light colored rubber veneer or organiccoating covers a staining rubber compound, the stainingingredients can diffuse through the veneer or coating and stainthe surface (diffusion sta
21、ining). This staining of light coloredsurfaces is objectionable to the consumer.5.2 These test methods provide a means of evaluatingstaining characteristics of rubber compounds but may notnecessarily duplicate the effects of natural exposure conditions.5.3 Results obtained should not be treated as b
22、eing equiva-lent to any natural exposure, unless the degree of quantitativecorrelation has been empirically established for the material inquestion.5.4 These test methods may be used for producer-consumeracceptance, referee purposes, and research and developmentwork.5.5 The two types of exposures (F
23、luorescent UV and XenonArc) are not equivalent and may produce different test results.METHOD ACONTACT STAIN6. Apparatus6.1 Circulating-Air OvenThe oven shall meet the require-ments of Specification E 145, Type 11 B.7. Materials and Manufacture7.1 Metal panels 50 mm (2 in.) square shall be cut fromsh
24、eet metal of approximately 0.9 mm (20 gauge) in thicknessthat has been coated with a desired organic finish. When thesetest methods are used to determine compliance with specifica-tions, the panels may be supplied by the purchaser and the typeof finish used may be the subject of agreement between th
25、epurchaser and the seller. The panels shall be aged for at least48 h after finishing and before use in this test.NOTE 1It is recommended that acrylic enamel be employed as anorganic coating for the metal panels (Delstar Acrylic EnamelDAR 2185white, in conjunction with Satin Primer DPE-1338, light gr
26、ay-nonsanding).38. Test Specimen8.1 The test specimen shall be prepared from a vulcanizedproduction part or from a test sheet in accordance withPractices D 3182 and D 3183. The specimen shall be rectan-gular in shape, 25 by 12 mm (1 by 0.5 in.) and of uniformthickness. If a specimen of this size can
27、not be prepared from aproduction part, a modification of this size may be used, whenagreed upon between the purchaser and the seller. The speci-men shall be tested as received, but extraneous contaminationand debris may be removed, without abrading the surface, bywashing with a mild soap solution or
28、 by mechanical means.9. Procedure9.1 Place two rubber specimens from the same materialbetween two metal plates, as shown in Fig. 1, with the finishedsurfaces of the panels in contact with the rubber.9.1.1 Place the metal panel-rubber “sandwich” thus formedin the oven maintained at a temperature of 7
29、0 6 2C (158 64F). Place a 0.5 kg (1 lb) mass on top of the sandwich (or anadjusted mass, if nonstandard specimens are being tested).9.1.2 Expose the assembly to the oven temperature for aspecified time; time intervals frequently used are 6, 24, 48, and96 h. In lieu of a specified time, 48 h shall be
30、 used as thedefault time interval. Take care that no other volatile or vaporproducing materials that might produce staining are in the testchamber.9.1.3 After the aging period, remove the assembly from theoven and separate the specimens cleanly from the sandwich.Then wash the panels with mild soap s
31、olution.9.2 Simultaneously test a metal control panel without arubber specimen to check the effect of the test conditions on thefinish itself. Expose no control panel more than once.9.3 One or more reference assemblies using rubber materi-als of known staining characteristics shall be included in th
32、etest.9.4 Consider any staining of the area that was in contactwith the specimen that is greater than the discoloration of the3The sole source of supply of the apparatus known to the committee at this timeis PPG Industries, Inc., Ditzler Automotive Finishes, Troy, MI 48084. If you areaware of altern
33、ative suppliers, please provide this information to ASTM Interna-tional Headquarters. Your comments will receive careful consideration at a meetingof the responsible technical committee,1which you may attend.FIG. 1 Method AContact Stain Test AssemblyD925062control panel as contact staining. Judge th
34、e degree of thiscontact stain to be greater or less than that of the referencestandard, or a numerical rating based on an arbitrary scale asagreed upon between the purchaser and the seller. Observe andrecord any staining beyond the immediate area of contact.METHOD BMIGRATION STAIN10. Apparatus10.1 F
35、luorescent UV/Condensation Apparatus (PracticeG 154)Use Fluorescent UV test apparatus that conforms tothe requirements defined in Practices G 151 and G 154; refer toFig. 2.10.1.1 The instrumentation shall be calibrated in accordancewith the requirements of the manufacturer; refer to section18.2.10.2
36、 Xenon Arc Light Apparatus (Practice G 155)Usexenon arc test apparatus that conforms to the requirementsdefined in Practices G 151 and G 155; refer to Fig. 3.10.2.1 The instrumentation shall be calibrated in accordancewith the requirements of the manufacturer; refer to section18.5.1.11. Materials an
37、d Manufacture11.1 Use metal panels as described in Section 7, except thatthe size shall be 75 by 100 mm (3 by 4 in.) for the standardspecimen and shall be no larger than 300 by 300 mm (12 by 12in.) for nonstandard specimens. Panels of this size are normallyused in purchaser-seller compliance testing
38、.12. Test Specimens12.1 Prepare the test specimens in accordance with Section8; refer to Fig. 1.13. Procedures13.1 The two procedures (Fluorescent UV and Xenon Arc)use different types of exposure sources and test conditionswhich may produce different test results. They shall not be usedinterchangeab
39、ly without supporting data that demonstratesequivalency of the procedures for the materials tested.13.2 For the allowed operational fluctuations of the speci-fied set points for irradiance, temperature and relative humid-ity, refer to Table A3.1 in Practice G 151. If the actualoperating conditions d
40、o not comply with the maximum allow-able fluctuations in Table A3.1 after the equipment has stabi-lized, discontinue the test and correct the cause of the problembefore continuing.13.3 Specimens should be confined to an exposure area inwhich the irradiance is at least 90 % of the irradiance at thece
41、nter of the exposure area. Unless it is known that irradianceuniformity meets this requirement, use one of the proceduresdescribed in Practice G 151, Section 5.1.4 to ensure equalradiant exposure on all specimens or to compensate fordifferences within the exposure chamber. If the specimens donot com
42、pletely fill the racks, fill the empty spaces with blankmetal panels to maintain the test conditions within the cham-ber.13.4 The apparatus shall be operated continuously. How-ever, if the test needs to be interrupted to perform routinemaintenance or inspection, it should be during a dry period.13.5
43、 Procedure for Exposure in Fluorescent UV/Condensation Apparatus (Practice G 154)Unless otherwisespecified, operate the fluorescent UV test apparatus withUVA-340 lamps in accordance with Practice G 154.13.5.1 Use the following exposure cycle: Set the irradiancelevel to 0.77 W/(m2nm) at 340 nm. Expos
44、e specimens to acontinuous cycle of 8 h light at 60C uninsulated black paneltemperature followed by4hofcondensation at 50C uninsu-lated black panel temperature.13.5.2 Periodically reposition specimens in conformance toPractices G 151 and G 154; refer to 13.3.13.5.3 Simultaneously test a control pane
45、l without rubber tocheck the effect of the test conditions on the finish itself.Expose no panel more than once.13.5.4 Also include in the test one or more specimens usingrubber materials of known staining characteristics.13.5.5 Consider any staining beyond the area that was incontact with the specim
46、en that is greater than the discolorationof the control panel as migration staining. Judge the degree ofthis stain to be greater or less than that of a standard or give anumerical rating based on an arbitrary scale of degree of stain,which may be agreed upon between the purchaser and theseller.13.6
47、Procedure for Exposure in Xenon Arc Apparatus(Practice G 155)Unless otherwise specified, use the follow-ing operating conditions:13.6.1 The xenon arc test apparatus shall be used with aDaylight Filter and conform to the spectral power distributionspecifications in Practice G 155.13.6.2 Set the irrad
48、iance level at 0.55 W/(m2nm) at 340 nm.For equivalent broad band irradiance levels at 300 to 400 nmand 300 to 800 nm, consult the manufacturer of the apparatus.13.6.3 The default exposure cycle shall be 102 min lightonly followed by 18 min light plus either water spray on thefront surface or immersi
49、on in water (see Note 2). The waterspray temperature is typically 21 6 5C, but may be lower ifFIG. 2 Spectral Power Distributions (SPD) of UVA-340 LampVersus DaylightD925063ambient water temperature is low and a holding tank is notused to store purified water. The immersion water is kept at aconstant temperature, which shall be less than 40C.NOTE 2In the immersion technique, the test specimens are placed ina chamber that is periodically flooded with either recirculated or runningwater, which completely covers the specimens. The maximum tempera-ture a
