1、Designation: D925 062D925 14Standard Test Methods forRubber PropertyStaining of Surfaces (Contact, Migration,and Diffusion)1This standard is issued under the fixed designation D925; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1 NOTEParagraphs 10.1.1, 10.2.1, and 18.6.4 were corrected editorially in December 2007.2 NOTEParagraph 12.1 was correc
3、ted editorially in August 2008.1. Scope1.1 These test methods cover techniques to evaluate three types of staining that rubber may cause when in contact with, or inproximity to, another surface that may be light colored.1.2 The test methods also describe how to qualitatively evaluate the degree of s
4、taining produced under the conditions ofexposure to heat alone or heat and light.1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.4 This standard does not purport to address all of the safety concerns, if any, associated
5、 with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1148 Test Method for Rubber DeteriorationDiscoloration from Ultra
6、violet (UV) or UV/Visible Radiation and Heat Exposureof Light-Colored SurfacesD3182 Practice for RubberMaterials, Equipment, and Procedures for Mixing Standard Compounds and Preparing StandardVulcanized SheetsD3183 Practice for RubberPreparation of Pieces for Test Purposes from ProductsE145 Specific
7、ation for Gravity-Convection and Forced-Ventilation OvensG151 Practice for Exposing Nonmetallic Materials in Accelerated Test Devices that Use Laboratory Light SourcesG154 Practice for Operating Fluorescent Ultraviolet (UV) Lamp Apparatus for Exposure of Nonmetallic MaterialsG155 Practice for Operat
8、ing Xenon Arc Light Apparatus for Exposure of Non-Metallic Materials3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 stain, contactdiscoloration of a product by another material or product in the area of direct contact.3.1.1.1 DiscussionA test for direct surface discoloration o
9、f rubber is covered by Test Method D1148.3.1.2 stain, diffusiondiscoloration of a light colored veneer or coating, caused by the diffusion of staining materials from therubber through the veneer or coating.3.1.2.1 Discussion1 These test methods are under the jurisdiction of ASTM Committee D11 on Rub
10、ber and are the direct responsibility of Subcommittee D11.15 on Degradation Tests.Current edition approved March 1, 2006May 1, 2014. Published April 2006May 2014. Originally approved in 1947. Last previous edition approved in 20002006 asD925 88 (2000).D925 062. DOI: 10.1520/D0925-06E02.10.1520/D0925
11、-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended onl
12、y to provide the user of an ASTM standard an indication of what 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 versi
13、onof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1The veneer or coating is in direct intimate contact with the underlying rubber.3.1.3 stain, migrationdisc
14、oloration, caused by constituents of a rubber, that occurs on any portion of the surface of any objectin the proximity of or adjacent to but not in direct contact with the rubber 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
15、BMigration Stain.4.1.3 Method CDiffusion Stain.4.2 Method ASpecimens to be tested for contact staining are sandwiched between two metal panels. The metal panels arefurnished with a desired light colored organic finish, which is in contact with the rubber. The assembly is exposed to elevatedtemperatu
16、res for a specified length of time and the specimens are then removed from the metal. The degree of staining of thesurface that was in contact with the rubber is rated against a reference standard and a control panel (a metal plate without rubber)which are simultaneously tested with the specimen.4.3
17、 Method BSpecimens to be tested for migration staining are placed on a metal plate with a desired light colored organicfinish, and exposed to either fluorescent UVA-340 lamps or filtered xenon arc radiation for a specified period of time. The degreeof staining beyond the area that was in contact wit
18、h the specimens is then rated against a reference standard and a control panel(a metal plate without rubber) which are simultaneously tested with the specimen.4.4 Method CDiffusion staining is tested on specimens provided with a light colored rubber veneer or organic coating,deposited from organic s
19、olvent or water base. The specimens are exposed to either fluorescent UVA-340 lamps or filtered xenonarc radiation, with their veneer or coated side up, for a specified period of time.Any staining of the light colored veneer or organiccoating is considered diffusion staining and rated against a refe
20、rence standard and a control sample of the veneer or organic coatingwithout the staining rubber.4.5 Specimens used in all three staining tests shall include one or more reference samples of known staining characteristics. Inaddition, the contact and migration staining tests shall include a metal pan
21、el, without rubber samples, to establish the effect of thetest conditions on the finished metal surface. The diffusion staining test shall include, as controls, a vulcanized sample of the rubberveneer by itself or a sample of the coating applied to aluminum foil.5. Significance and Use5.1 Rubber in
22、contact with light colored organic finishes may stain the surfaces in contact with the rubber (contact staining) andsurfaces adjacent to or beyond the rubber (migration staining), especially under conditions of heat, pressure, or sunlight. When alight colored rubber veneer or organic coating covers
23、a staining rubber compound, the staining ingredients can diffuse through theveneer or coating and stain the surface (diffusion staining). This staining of light colored surfaces is objectionable to the consumer.5.2 These test methods provide a means of evaluating staining characteristics of rubber c
24、ompounds but may not necessarilyduplicate the effects of natural exposure conditions.5.3 Results obtained should not be treated as being equivalent to any natural exposure, unless the degree of quantitativecorrelation has been empirically established for the material in question.5.4 These test metho
25、ds may be used for producer-consumer acceptance, referee purposes, and research and development work.5.5 The two types of exposures (Fluorescent UV and Xenon Arc) are not equivalent and may produce different test results.METHOD ACONTACT STAIN6. Apparatus6.1 Circulating-Air OvenThe oven shall meet th
26、e requirements of Specification E145, Type 11 B.7. Materials and Manufacture7.1 Metal panels 50 mm (2 in.) square shall be cut from sheet metal of approximately 0.9 mm (20 gauge) in thickness that hasbeen coated with a desired organic finish.When these test methods are used to determine compliance w
27、ith specifications, the panelsmay be supplied by the purchaser and the type of finish used may be the subject of agreement between the purchaser and the seller.The panels shall be aged for at least 48 h after finishing and before use in this test.NOTE 1It is recommended that acrylic enamel be employ
28、ed as an organic coating for the metal panels (Delstar Acrylic EnamelDAR 2185 white,D925 142in conjunction with Satin Primer DPE-1338, light gray-nonsanding).38. Test Specimen8.1 The test specimen shall be prepared from a vulcanized production part or from a test sheet in accordance with PracticesD3
29、182 and D3183. The specimen shall be rectangular in shape, 25 by 12 mm (1 by 0.5 in.) and of uniform thickness. If a specimenof this size cannot be prepared from a production part, a modification of this size may be used, when agreed upon between thepurchaser and the seller. The specimen shall be te
30、sted as received, but extraneous contamination and debris may be removed,without abrading the surface, by washing with a mild soap solution or by mechanical means.9. Procedure9.1 Place two rubber specimens from the same material between two metal plates, as shown in Fig. 1, with the finished surface
31、sof the panels in contact with the rubber.9.1.1 Place the metal panel-rubber “sandwich” thus formed in the oven maintained at a temperature of 70 6 2C (158 6 4F).Place a 0.5 kg (1 lb) mass on top of the sandwich (or an adjusted mass, if nonstandard specimens are being tested).9.1.2 Expose the assemb
32、ly to the oven temperature for a specified time; time intervals frequently used are 6, 24, 48, and 96 h.In lieu of a specified time, 48 h shall be used as the default time interval. Take care that no other volatile or vapor producingmaterials that might produce staining are in the test chamber.9.1.3
33、 After the aging period, remove the assembly from the oven and separate the specimens cleanly from the sandwich. Thenwash the panels with mild soap solution.9.2 Simultaneously test a metal control panel without a rubber specimen to check the effect of the test conditions on the finishitself. Expose
34、no control panel more than once.9.3 One or more reference assemblies using rubber materials of known staining characteristics shall be included in the test.9.4 Consider any staining of the area that was in contact with the specimen that is greater than the discoloration of the controlpanel as contac
35、t staining. Judge the degree of this contact stain to be greater or less than that of the reference standard, or anumerical rating based on an arbitrary scale as agreed upon between the purchaser and the seller. Observe and record any stainingbeyond the immediate area of contact.METHOD BMIGRATION ST
36、AIN10. Apparatus10.1 Fluorescent UV/Condensation Apparatus (Practice G154)Use Fluorescent UV test apparatus that conforms to therequirements defined in Practices G151 and G154; refer to Fig. 2.10.1.1 The instrumentation shall be calibrated in accordance with the requirements of the manufacturer.10.2
37、 Xenon Arc Light Apparatus (Practice G155)Use xenon arc test apparatus that conforms to the requirements defined inPractices G151 and G155; refer to Fig. 3.10.2.1 The instrumentation shall be calibrated in accordance with the requirements of the manufacturer.11. Materials and Manufacture11.1 Use met
38、al panels as described in Section 7, except that the size shall be 75 by 100 mm (3 by 4 in.) for the standard specimenand shall be no larger than 300 by 300 mm (12 by 12 in.) for nonstandard specimens. Panels of this size are normally used inpurchaser-seller compliance testing.12. Test Specimens12.1
39、 Prepare the test specimens in accordance with Section 8.3 The sole source of supply of the apparatus known to the committee at this time is PPG Industries, Inc., Ditzler Automotive Finishes, Troy, MI 48084. If you are awareof alternative suppliers, please provide this information toASTM Internation
40、al Headquarters.Your comments will receive careful consideration at a meeting of the responsibletechnical committee,1 which you may attend.FIG. 1 Method AContact Stain Test AssemblyD925 14313. Procedures13.1 The two procedures (Fluorescent UV and Xenon Arc) use different types of exposure sources an
41、d test conditions whichmay produce different test results. They shall not be used interchangeably without supporting data that demonstrates equivalencyof the procedures for the materials tested.13.2 For the allowed operational fluctuations of the specified set points for irradiance, temperature and
42、relative humidity, referto Table A3.1 in Practice G151. If the actual operating conditions do not comply with the maximum allowable fluctuations inTable A3.1 after the equipment has stabilized, discontinue the test and correct the cause of the problem before continuing.13.3 Specimens should be confi
43、ned to an exposure area in which the irradiance is at least 90 % of the irradiance at the centerof the exposure area. Unless it is known that irradiance uniformity meets this requirement, use one of the procedures describedin Practice G151, Section 5.1.4 to ensure equal radiant exposure on all speci
44、mens or to compensate for differences within theexposure chamber. If the specimens do not completely fill the racks, fill the empty spaces with blank metal panels to maintain thetest conditions within the chamber.13.4 The apparatus shall be operated continuously. However, if the test needs to be int
45、errupted to perform routine maintenanceor inspection, it should be during a dry period.13.5 Procedure for Exposure in Fluorescent UV/Condensation Apparatus (Practice G154)Unless otherwise specified, operatethe fluorescent UV test apparatus with UVA-340 lamps in accordance with Practice G154.13.5.1 U
46、se the following exposure cycle: Set the irradiance level to 0.77 W/(m2nm) at 340 nm. Expose specimens to acontinuous cycle of 8 h light at 60C uninsulated black panel temperature followed by 4 h of condensation at 50C uninsulatedblack panel temperature.13.5.2 Periodically reposition specimens in co
47、nformance to Practices G151 and G154; refer to 13.3.13.5.3 Simultaneously test a control panel without rubber to check the effect of the test conditions on the finish itself. Exposeno panel more than once.13.5.4 Also include in the test one or more specimens using rubber materials of known staining
48、characteristics.13.5.5 Consider any staining beyond the area that was in contact with the specimen that is greater than the discoloration of thecontrol panel as migration staining. Judge the degree of this stain to be greater or less than that of a standard or give a numericalrating based on an arbi
49、trary scale of degree of stain, which may be agreed upon between the purchaser and the seller.13.6 Procedure for Exposure in Xenon Arc Apparatus (Practice G155)Unless otherwise specified, use the following operatingconditions:13.6.1 The xenon arc test apparatus shall be used with a Daylight Filter and conform to the spectral power distributionspecifications in Practice G155.13.6.2 Set the irradiance level at 0.55 W/(m2nm) at 340 nm. For equivalent broad band irradiance levels at 300 to 400 nm and300 to 800 nm, consult the manufacturer of th
