1、Designation: D 1148 07aStandard Test Method forRubber DeteriorationDiscoloration from Ultraviolet (UV)and Heat Exposure of Light-Colored Surfaces1This standard is issued under the fixed designation D 1148; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 the case of revision, the year 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.(This test method was prepared jointly by the Society of Automotive Engineers and ASTM Interna
3、tional.)1. Scope1.1 This test method covers techniques to evaluate thesurface discoloration of white or light-colored vulcanizedrubber that may occur when subjected to UV or UV/visibleexposure from specified sources under controlled conditions ofrelative humidity, or moisture, and temperature.1.2 Th
4、is test method also describes how to qualitativelyevaluate the degree of discoloration produced under suchconditions.1.3 The term “discoloration” applies to a color change of therubber sample, as distinguished from staining (see Note 1), thatrefers to a color change of a metal finish in contact with
5、 oradjacent to the rubber specimen.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the use
6、r of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE 1Tests for staining are covered by Test Methods D 925.2. Referenced Documents2.1 ASTM Standards:2D 925 Test Methods for Rubber PropertyStaining of Sur
7、-faces (Contact, Migration, and Diffusion)D 2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinatesD 3182 Practice for RubberMaterials, Equipment, andProcedures for Mixing Standard Compounds and Prepar-ing Standard Vulcanized SheetsD 3183
8、Practice for RubberPreparation of Product Piecesfor Test Purposes from ProductsG 151 Practice for Exposing Nonmetallic Materials in Ac-celerated Test Devices that Use Laboratory Light SourcesG 154 Practice for Operating Fluorescent Light Apparatusfor UV Exposure of Nonmetallic MaterialsG 155 Practic
9、e for Operating Xenon Arc Light Apparatusfor Exposure of Non-Metallic Materials3. Summary of Test Method3.1 Specimens to be tested for discoloration are exposed toUV or UV/visible radiation. The specimens shall include oneor more control specimens of known discoloration character-istics.3.2 After ex
10、posing the specimens to actinic radiation forspecified periods of time, under controlled conditions ofrelative humidity, or moisture, and temperature, the degree ofdiscoloration is rated against discoloration of the controlspecimens, which have been exposed simultaneously with thetest specimens.4. S
11、ignificance and Use4.1 The surface of white or light-colored vulcanized rubberarticles, or vulcanized rubber covered with an organic finish,may discolor when exposed to conditions of humidity, ormoisture, heat, and sunlight. This change in color of light-colored rubber surfaces is objectionable to t
12、he consumer.4.2 Results obtained should be treated only as indicating theeffect of irradiance from the specified source (either UVA-340lamps or a xenon arc with a Daylight Filter) and not asequivalent to the result of any natural exposure, unless thedegree of quantitative correlation has been empiri
13、cally estab-lished for the material in question.4.3 This test method may be used for producer-consumeracceptance, referee purposes, and research and developmentwork.1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.15 on D
14、egradation Tests.Current edition approved May 1, 2007. Published June 2007. Originallyapproved in 1951. Last previous edition approved in 2007 as D 1148 07.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AST
15、MStandards 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.5. Apparatus5.1 Fluorescent UV/Condensation Apparatus (PracticeG 154)Use Fluorescent UV te
16、st apparatus that conforms tothe requirements defined in Practices G 151 and G 154.5.1.1 Unless otherwise specified, the spectral power distri-bution (SPD) of the fluorescent lamp shall conform to therequirements of Table 1 in Practice G 154 (UVA-340 Lamp).Refer to Fig. 1.5.2 Xenon Arc Light Apparat
17、us (Practice G 155)Usexenon arc test apparatus that conforms to the requirementsdefined in Practices G 151 and G 155.5.2.1 Unless otherwise specified, the spectral power distri-bution (SPD) of the filtered xenon lamp shall conform to therequirements of Table 1 in Practice G 155 (Xenon Arc withDaylig
18、ht Filter). Refer to Fig. 2.5.3 Color meter capable of measuring tristimulus colors foramber, blue, and green with or without automatic calculationfor Labor L* a* b* values. If without automatic calculations,a computer program should be available for this calculation.6. Test Specimen6.1 The test spe
19、cimen shall be prepared from a vulcanizedproduction part or from a test slab prepared in accordance withPractices D 3182 and D 3183. The specimen shall be rectan-gular in shape, 62 by 12 mm (2.4 by 0.5 in.). If a specimen ofthis size cannot be prepared from a production part, a modifi-cation of the
20、size may be agreed upon between the purchaserand the seller.6.2 An unexposed file specimen of the same compound asthat stated in 6.1 shall be prepared and reserved for colorcomparisons without being subjected to exposure.7. Procedure7.1 The two procedures (Fluorescent UV/Condensation andXenonArc) co
21、ntain different types of exposure sources and testconditions and may produce different test results. They cannotbe used interchangeably without supporting data that demon-strates equivalency of the procedures for the materials tested.7.2 Refer to Table A3.1 in Practice G 151 for the allowedoperation
22、al fluctuations of the specified set points for irradi-ance, temperature, and relative humidity. If the actual operatingconditions do not comply with the maximum allowable fluc-tuations in Table A3.1 after the equipment has stabilized,discontinue the test and correct the cause of the problem beforec
23、ontinuing.7.3 Specimens should be confined to an exposure area inwhich the irradiance is at least 90 % of the irradiance at thecenter 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 ens
24、ure equalradiant exposure on all specimens, or to compensate fordifferences within the exposure chamber. If the specimens donot completely fill the racks, fill the empty spaces with blankmetal panels to maintain the test conditions within the cham-ber. The apparatus shall be operated continuously. H
25、owever, ifthe test needs to be interrupted to perform routine maintenanceor inspection, it should be during a dry period.7.4 Procedure for Exposure in Fluorescent UV/Condensation Apparatus (Practice G 154)Unless otherwisespecified, operate the fluorescent UV test apparatus withUVA-340 lamps in accor
26、dance with Practice G 154.7.4.1 Use the following exposure cycle: Set the irradiancelevel to 0.77 W / (m2. nm) at 340 nm. Expose specimens to acontinuous cycle of 8 h light at 60C uninsulated black paneltemperature followed by4hofcondensation at 50C uninsu-lated black panel temperature.7.5 Procedure
27、 for Exposure in Xenon Arc Apparatus (Prac-tice G 155)Unless otherwise specified, use the followingoperating conditions:7.5.1 The xenon arc test apparatus shall be used with aDaylight Filter and conform to the spectral power distributionspecifications in Practice G 155.FIG. 1 Spectral Power Distribu
28、tions of UVA-340 Lamp Versus DaylightD 1148 07a27.5.2 Set the irradiance level at 0.55 W / (m2 nm) at 340nm. Consult the manufacturer of the apparatus for equivalentbroad band irradiance levels at 300 to 400 nm and 300 to 800nm.7.5.3 The default exposure cycle shall be 102 min light onlyfollowed by
29、18 min light plus either water spray on the frontsurface or immersion in water (refer to Note 2). The waterspray temperature is typically 21 6 5C, but may be lower ifambient water temperature is low and a holding tank is notused to store purified water. The immersion water is kept at aconstant tempe
30、rature, which shall be less than 40C.NOTE 2Water spray and immersion in water frequently producedifferent results. In the immersion technique, the test specimens are placedin a chamber that is periodically flooded with either recirculated orrunning water, which completely covers the specimens. The m
31、aximumtemperature attained by a black colored specimen is determined with theblack standard thermometer (BST) held under water on the same planeand distance from the surface as the test specimens. The immersion systemis made from corrosion resistant materials that do not contaminate thewater.7.5.4 S
32、et the uninsulated Black Panel Temperature (BPT) at63C during the dry period of exposure to light. Consult themanufacturer of the apparatus for the equivalent insulatedblack panel temperature (Black Standard Temperature (BST).7.5.5 Relative humidity shall be set at 60 % during the dryperiod of expos
33、ure to light in xenon arc apparatus that providesfor control of relative humidity.7.5.6 The chamber air temperature shall be set at 44C inapparatus that provides for adjustment of the chamber airtemperature.7.6 One or more control specimens using rubber material ofknown discoloration characteristics
34、 shall be included.7.7 Any change in color of a test specimen in relation to theoriginal sample shall be considered as discoloration.7.7.1 The degree of discoloration can be judged visually tobe greater or less than the control specimen and can be givena numerical rating based on an arbitrary scale
35、of degree ofdiscoloration which may be agreed upon between the purchaserand the seller.7.7.2 The change in color can be measured instrumentallyusing commercial color meters (refer to Note 3) for specimensprepared according to Section 6. Calculate the differencebetween an unexposed specimen and the e
36、xposed specimen, asfollows:DE 5 EU2 EE(1)DE* 5 EU* 2 EE* (2)where:DE = difference between unexposed and exposed specimenEU= unexposed specimenEE= exposed specimenNOTE 3Some color meters calculate DE and others calculate DE*,while some may calculate both. Either expression is suitable for use in this
37、test method, but one must not mix them together.Acomplete equation canbe found in Practice D 2244.8. Report8.1 The report shall include the following information:8.1.1 Type of radiation used, either UVA-340 or filteredxenon arc lamp;8.1.2 Exposure time in hours;8.1.3 Date of test;8.1.4 Identificatio
38、n of test and control specimens;8.1.5 Size and shape of specimen(s) if not in accordancewith the standard shape and size;8.1.6 An estimate of the degree of discoloration accordingto a visual estimation, described in 7.7.1, or an instrumentalevaluation according to 7.7.2.9. Precision and Bias9.1 A pr
39、ecision and bias study has not yet been prepared.FIG. 2 Spectral Power Distributions of Xenon Arc with Daylight Filter Versus DaylightD 1148 07a39.2 BiasBias cannot be determined because no acceptablestandard weathering reference materials are available.10. Keywords10.1 fluorescent UV; heat discolor
40、ation; rubber products;ultraviolet; ultraviolet light discoloration; UVA-340; xenon arcAPPENDIX(Nonmandatory Information)X1. COLOR METERX1.1 Set up the color meter according to the directionssupplied by the manufacturer for optimum performance. Thiswill include any necessary calibrations.X1.1.1 If t
41、he color meter requires a standard plaque, ob-serve any precautions for plaque storage, cleanliness, andre-calibration.X1.1.2 Obtain amber, blue, and green tristimulus reflectancereadings for each specimen to be measured, including theunexposed file specimen (which was not exposed to ultravioletligh
42、t).X1.1.2.1 Color meters present data differently; however, Lab and L* a* b* data can be obtained from any color metereither as part of the instrumental calculations or, if not,computer programs can be used to generate the necessary data.X1.2 To assess the discoloration of a sample as comparedto the
43、 unexposed file specimen, subtract the EEor EE* value ofthe exposed specimen from the EUor EU* value of theunexposed specimen. This is the difference (DE)or(DE*)onwhich the discoloration evaluation is based. See 7.7.2.ASTM International takes no position respecting the validity of any patent rights
44、asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination 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 tim
45、e by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will r
46、eceive 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 I
47、nternational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 1148 07a4
