1、Designation: D1148 07aD1148 13Standard Test Method forRubber DeteriorationDiscoloration from Ultraviolet (UV) orUV/Visible Radiation and Heat Exposure of Light-ColoredSurfaces1This standard is issued under the fixed designation D1148; the number immediately following the designation indicates the ye
2、ar oforiginal adoption or, in the case of revision, the 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.(This test method was prepared jointly by the Society of Automotiv
3、e Engineers and ASTM International.)1. Scope1.1 This test method covers techniques to evaluate the surface discoloration of white or light-colored vulcanized rubber that mayoccur when subjected to UV or UV/visible exposure from specified sources under controlled conditions of relative humidity, ormo
4、isture, and temperature.1.2 This test method also describes how to qualitatively evaluate the degree of discoloration produced under such conditions.1.3 The term “discoloration” applies to a color change of the rubber sample, as distinguished from staining (see Note 1), thatrefers to a color change
5、of a metal finish in contact with or adjacent to the rubber specimen.1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its us
6、e. 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.NOTE 1Tests for staining are covered by Test Methods D925.2. Referenced Documents2.1 ASTM Standards:2D925 Test Methods fo
7、r Rubber PropertyStaining of Surfaces (Contact, Migration, and Diffusion)D2244 Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color CoordinatesD3182 Practice for RubberMaterials, Equipment, and Procedures for Mixing Standard Compounds and Preparing St
8、andardVulcanized SheetsD3183 Practice for RubberPreparation of Pieces for Test Purposes from ProductsG151 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 N
9、onmetallic MaterialsG155 Practice for Operating Xenon Arc Light Apparatus for Exposure of Non-Metallic Materials3. Summary of Test Method3.1 Specimens to be tested for discoloration are exposed to UV or UV/visible radiation. The specimens shall include one ormore control specimens of known discolora
10、tion characteristics.3.2 After exposing the specimens to actinic radiation for specified periods of time, under controlled conditions of relativehumidity, or moisture, and temperature, the degree of discoloration is rated against discoloration of the control specimens, whichhave been exposed simulta
11、neously with the test specimens.4. Significance and Use4.1 The surface of white or light-colored vulcanized rubber articles, or vulcanized rubber covered with an organic finish, maydiscolor when exposed to conditions of humidity, or moisture, heat, and sunlight. This change in color of light-colored
12、 rubbersurfaces is objectionable to the consumer.1 This test method is under the jurisdiction of ASTM Committee D11 on Rubber and is the direct responsibility of Subcommittee D11.15 on Degradation Tests.Current edition approved May 1, 2007Jan. 1, 2013. Published June 2007February 2013. Originally ap
13、proved in 1951. Last previous edition approved in 2007 asD1148 07.D1148 07a. DOI: 10.1520/D1148-07A.10.1520/D1148-13.2 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
14、the standards 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 what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes
15、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 the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United
16、 States14.2 Results obtained should be treated only as indicating the effect of irradiance from the specified source (either UVA-340lamps or a xenon arc with a Daylight Filter) and not as equivalent to the result of any natural exposure, unless the degree ofquantitative correlation has been empirica
17、lly established for the material in question.4.3 This test method may be used for producer-consumer acceptance, referee purposes, and research and development work.5. Apparatus5.1 Fluorescent UV/Condensation Apparatus (Practice G154)Use Fluorescent UV test apparatus that conforms to therequirements
18、defined in Practices G151 and G154.5.1.1 Unless otherwise specified, the spectral power distribution (SPD) of the fluorescent lamp shall conform to therequirements of Table 1 in Practice G154 (UVA-340 Lamp). Refer to Fig. 1.5.2 Xenon Arc Light Apparatus (Practice G155)Use xenon arc test apparatus th
19、at conforms to the requirements defined inPractices G151 and G155.5.2.1 Unless otherwise specified, the spectral power distribution (SPD) of the filtered xenon lamp shall conform to therequirements of Table 1 in Practice G155 (Xenon Arc with Daylight Filter). Refer to Fig. 2.5.3 Color meter capable
20、of measuring tristimulus colors for amber, blue, and green with or without automatic calculation forL ab or L* a* b* values. If without automatic calculations, a computer program should be available for this calculation.6. Test Specimen6.1 The test specimen shall be prepared from a vulcanized produc
21、tion part or from a test slab prepared in accordance withPractices D3182 and D3183. The specimen shall be rectangular in shape, 62 by 12 mm (2.4 by 0.5 in.). If a specimen of this sizecannot be prepared from a production part, a modification of the size may be agreed upon between the purchaser and t
22、he seller.6.2 An unexposed file specimen of the same compound as that stated in 6.1 shall be prepared and reserved for color comparisonswithout being subjected to exposure.7. Procedure7.1 The two procedures (Fluorescent UV/Condensation and Xenon Arc) contain different types of exposure sources and t
23、estconditions and may produce different test results. They cannot be used interchangeably without supporting data that demonstratesequivalency of the procedures for the materials tested.7.2 Refer to Table A3.1 in Practice G151 for the allowed operational fluctuations of the specified set points for
24、irradiance,temperature, and relative humidity. 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.7.3 Specimens should be confined to an
25、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 specimens, or
26、to compensate for differences within theFIG. 1 Spectral Power Distributions of UVA-340 Lamp Versus DaylightD1148 132exposure 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. The apparatus shal
27、l be operated continuously. However, if the test needs to be interrupted toperform routine maintenance or inspection, it should be during a dry period.7.4 Procedure for Exposure in Fluorescent UV/Condensation Apparatus (Practice G154)Unless otherwise specified, operatethe fluorescent UV test apparat
28、us with UVA-340 lamps in accordance with Practice G154.7.4.1 Use the following exposure cycle: Set the irradiance level to 0.77 W / (m2. nm) 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 uninsulatedblac
29、k panel temperature.7.5 Procedure for Exposure in Xenon Arc Apparatus (Practice G155)Unless otherwise specified, use the following operatingconditions:7.5.1 The xenon arc test apparatus shall be used with a Daylight Filter and conform to the spectral power distributionspecifications in Practice G155
30、.7.5.2 Set the irradiance level at 0.55 W / (m2 nm) at 340 nm. Consult the manufacturer of the apparatus for equivalent broadband irradiance levels at 300 to 400 nm and 300 to 800 nm.7.5.3 The default exposure cycle shall be 102 min light only followed by 18 min light plus either water spray on the
31、front surfaceor immersion in water (refer to Note 2). The water spray temperature is typically 21 6 5C, but may be lower if ambient watertemperature is low and Note 3a holding tank is not used to store purified water. The immersion water is kept at a constanttemperature, which shall be less than 40C
32、. ).NOTE 2Water spray and immersion in water frequently produce different results. In the immersion technique, the test specimens are placed in achamber that is periodically flooded with either recirculated or running water, which completely covers the specimens.The maximum temperature attainedby a
33、black colored specimen is determined with the black standard thermometer (BST) held under water on the same plane and distance from the surfaceas the test specimens. The immersion system is made from corrosion resistant materials that do not contaminate the water.NOTE 3Spray water can be fresh or re
34、-circulated from a holding tank. The temperature of the spray water is uncontrolled and for fresh water typicallyranges between 16 and 26C. Re-circulated spray water can be at a higher temperature. Immersion water is generally in a holding tank for re-circulation.The uncontrolled temperature of the
35、re-circulated immersion water during operation of the weathering device typically ranges between 45 and 55C.7.5.4 Set the uninsulated Black Panel Temperature (BPT) at 63C during the dry period of exposure to light. Consult themanufacturer of the apparatus for the equivalent insulated black panel tem
36、perature (Black Standard Temperature (BST).7.5.5 Relative humidity shall be set at 60 % during the dry period of exposure to light in xenon arc apparatus that provides forcontrol of relative humidity.7.5.6 The chamber air temperature shall be set at 44C in apparatus that provides for adjustment of t
37、he chamber air temperature.7.6 One or more control specimens using rubber material of known discoloration characteristics shall be included.7.7 Any change in color of a test specimen in relation to the original sample shall be considered as discoloration.7.7.1 The degree of discoloration can be judg
38、ed visually to be greater or less than the control specimen and can be given anumerical rating based on an arbitrary scale of degree of discoloration which may be agreed upon between the purchaser and theseller.FIG. 2 Spectral Power Distributions of Xenon Arc with Daylight Filter Versus DaylightD114
39、8 1337.7.2 The change in color can be measured instrumentally using commercial color meters (refer to Note 34) for specimensprepared according to Section 6. Calculate the difference between an unexposed specimen and the exposed specimen, as follows:E5EU 2EE (1)E*5EU*2EE* (2)where:E = difference betw
40、een unexposed and exposed specimenEU = unexposed specimenEE = exposed specimenNOTE 4Some color meters calculate E and others calculate E*, while some may calculate both. Either expression is suitable for use in this testmethod, but one must not mix them together. A complete equation can be found in
41、Practice D2244.8. Report8.1 The report shall include the following information:8.1.1 Type of radiation used, either UVA-340 or filtered xenon arc lamp;8.1.2 Exposure time in hours;8.1.3 Date of test;8.1.4 Identification of test and control specimens;8.1.5 Size and shape of specimen(s) if not in acco
42、rdance with the standard shape and size;8.1.6 An estimate of the degree of discoloration according to a visual estimation, described in 7.7.1, or an instrumentalevaluation according to 7.7.2.9. Precision and Bias9.1 A precision and bias study has not yet been prepared.9.2 BiasBias cannot be determin
43、ed because no acceptable standard weathering reference materials are available.10. Keywords10.1 fluorescent UV; heat discoloration; rubber products; ultraviolet; ultraviolet light discoloration; UVA-340; xenon arcAPPENDIX(Nonmandatory Information)X1. COLOR METERX1.1 Set up the color meter according
44、to the directions supplied by the manufacturer for optimum performance. This will includeany necessary calibrations.X1.1.1 If the color meter requires a standard plaque, observe any precautions for plaque storage, cleanliness, and re-calibration.X1.1.2 Obtain amber, blue, and green tristimulus refle
45、ctance readings for each specimen to be measured, including the unexposedfile specimen (which was not exposed to ultraviolet light).(UV) or UV/visible radiation).X1.1.2.1 Color meters present data differently; however, Lab and L*a*b* data can be obtained from any color meter either as partof the ins
46、trumental calculations or, if not, computer programs can be used to generate the necessary data.X1.2 To assess the discoloration of a sample as compared to the unexposed file specimen, subtract the EE or EE* value of theexposed specimen from the EU or EU* value of the unexposed specimen. This is the
47、 difference (E) or (E* ) on which thediscoloration evaluation is based. See 7.7.2.D1148 134ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination
48、 of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdraw
49、n.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-
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