1、Designation: D1435 13Standard Practice forOutdoor Weathering of Plastics1This standard is issued under the fixed designation D1435; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses
2、indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This practice is intended to cover procedures for theexposure of plastic ma
3、terials to weather.NOTE 1See Practice G24 for aging under glass.1.2 This practice is limited to the method by which thematerial is to be exposed and the general procedure to befollowed. It is intended for use with finished articles ofcommerce as well as with all sizes and shapes of testspecimens.1.3
4、 Means of evaluation of the effects of weathering willdepend on the intended use for the test material.1.4 The values stated in SI units are to be regarded as thestandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility
5、 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.NOTE 2This standard and ISO 877.2-2009, Method A, are technicallyequivalent.2. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating
6、 to PlasticsD1600 Terminology forAbbreviated Terms Relating to Plas-ticsE772 Terminology of Solar Energy ConversionG7 Practice for Atmospheric Environmental Exposure Test-ing of Nonmetallic MaterialsG24 Practice for Conducting Exposures to Daylight FilteredThrough GlassG113 Terminology Relating to N
7、atural and Artificial Weath-ering Tests of Nonmetallic MaterialsG141 Guide for Addressing Variability in Exposure Testingof Nonmetallic MaterialsG147 Practice for Conditioning and Handling of Nonmetal-lic Materials for Natural and Artificial Weathering Tests2.2 ISO Standard:ISO 877.2-2009 PlasticsMe
8、thods of exposure to solarradiationPart 2: Direct weathering and exposure behindglass33. Terminology3.1 DefinitionsFor definitions of technical terms pertain-ing to plastics used in this practice, see Terminologies D883,D1600, G113, and E772.4. Significance and Use4.1 Tests conducted in accordance w
9、ith this practice areused to evaluate the stability of plastic materials when they areexposed outdoors. The relative durability of plastics in outdooruse can be very different depending on the location of theexposure because of differences in ultraviolet (UV) radiation,time of wetness, temperature,
10、pollutants, and other factors. Itcannot be assumed, therefore, that results from one exposure ina single location will be useful for determining relativedurability in a different location. Exposures in several locationswith different climates that represent a broad range of antici-pated service cond
11、itions are recommended.4.1.1 Because of year-to-year climatological variations, re-sults from a single exposure test cannot be used to predict theabsolute rate at which a material degrades. Several years ofrepeat exposures are needed to get an average test result for agiven location.4.2 The results
12、of short-term exposure tests can provide anindication of relative outdoor performance, but they should notbe used to predict the absolute long-term performance of amaterial. The results of tests conducted for less than twelvemonths will depend on the particular season of the year inwhich they begin.
13、1This practice is under the jurisdiction ofASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.50 on Durability of Plastics.Current edition approved June 1, 2013. Published July 2013. Originally approvedin 1956. Last previous edition approved in 2005 as D1435 - 05. DOI
14、: 10.1520/D1435-13.2For referenced ASTM standards, visit the ASTM website, 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.3Available from American National Standard
15、s Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Apparatus5.1 The test site shall
16、conform to the requirements ofPractice G7. Unless otherwise specified, position exposureracks so that they face the equator. The angle of the exposurerack relative to the horizontal can vary depending upon theend-use conditions that are being evaluated.NOTE 3Test sites at latitudes less than 2327 fr
17、om the equator ineither hemisphere will have a period during the year when the declinationof the sun will exceed the latitude of the site.5.1.1 At-Latitude RacksThese racks shall be adjusted suchthat the exposed surfaces are at an angle from the horizontalcorresponding exactly to the site latitude a
18、ngle (Note 4).NOTE 4Exposure at the latitude angle is typically used to compareexposures from different locations when solar radiation is the main factor,and temperature and moisture are not being considered.5.1.2 45 RacksThese racks shall be adjusted such that theexposed surfaces of specimens are a
19、t an angle of 45 to thehorizontal.5.1.3 90 RacksThese racks shall be adjusted such that theexposed surfaces of specimens are at an angle of 90 to thehorizontal.5.1.4 5 RacksThese racks shall be adjusted such that theexposed surfaces of specimens are at an angle of 5 to thehorizontal.5.1.5 Horizontal
20、 RacksThese racks shall be positionedsuch that the exposed surfaces of the specimens are horizontal(Note 5).NOTE 5To provide moisture runoff for most horizontal-type testing ofplastics, 5 south exposure is usually preferred. However, plastic roofingmembranes, artificial turf, and other plastics that
21、 may be exposed athorizontal in their end-use condition should be exposed at 0 horizontal.5.1.6 Other-Angle RacksThese racks shall be adjustedsuch that the exposed surfaces of specimens are at a tilt anglemutually agreed upon between the interested parties.5.2 Materials and Manner of ConstructionTes
22、t racks andhardware shall conform to the requirements of Practice G7 andshall provide for attachment of specimens or holders of anyconvenient width and length. The structural members of thetest racks shall not constitute a backing to the specimens undertest unless it is used in relation to an end-us
23、e system. Fastenersused to attach specimens to the test rack shall provide forsecure attachment but allow specimens to expand or contractwith thermal changes, moisture absorption or desorption, orplasticizer loss.5.3 Specimen Holders:5.3.1 Some specimens under test will not be of an exact sizefor mo
24、unting directly on the frame. Specimen holders shouldbe used to support the many sizes of specimens involved in thistesting. The specimen holder shall not constitute a backing forthat portion of the material to be evaluated unless it is used inrelation to an end-use system.5.3.2 The specimen holders
25、 shall be constructed of an inertmaterial. (Aluminum extruded shapes have been found to besuitable.)5.3.3 The design of the specimen holders shall be such thateach specimen or sheet in a holder cannot shift its position, yetis not constrained (that is, it is free to expand or contract withthermal ch
26、anges, swell because of moisture absorption, orshrink because of plasticizer loss).5.3.4 Frame HoldersThese holders are in the shape of aframe that may be subdivided as necessary to provide properspacing of the specimens. The exposure aperture of each frameshall be of sufficient size to expose the e
27、ntire test area of eachspecimen when sufficient specimens are contained. Thismethod of mounting is shown in Fig. 1.5.3.5 Plate HoldersThis type of holder is a universalpanel consisting of a slotted-aluminum plate on which electri-cal white glaze spool or knob porcelain insulators are mountedat prope
28、r positions to affix various-sized specimens. Thespecimens are mounted in the grooves of the insulators at afixed distance of at least 11 mm from the slotted back plate.The insulators provide inert mounting while the slotted platepermits free circulation of air behind the specimen. Thismethod of mou
29、nting is shown in Fig. 2.5.4 Instruments for Measuring Climatological Data:5.4.1 Instruments Used to Measure Ambient Temperatureand Relative HumidityInstruments and procedures used formeasurement of ambient temperature and relative humidityshall be in accordance with Practice G7.5.4.2 Instruments Us
30、ed to Measure Solar RadiationInstruments and calibration procedures used for measurementof total solar radiation, total solar ultraviolet radiation, ornarrow band solar ultraviolet radiation shall be in accordancewith Practice G7.6. Sampling6.1 Sampling shall be in accordance with the pertinentconsi
31、derations outlined in Guide G141.7. Test Specimens7.1 Exposure test specimens may be of any size or shapethat can be mounted in a holder or applied directly to the racks.They may be specimens suited to the means of evaluating theeffects of weathering on a specific physical property, or theymay be la
32、rger specimens from which smaller specimens forevaluation may be cut. Exposure test specimens should beFIG. 1 Suitably Mounted Specimens in a FrameD1435 132large enough that mounting edges may be removed whereevaluation test results would otherwise be affected.7.2 As far as practical, exposure test
33、specimens shall simu-late service conditions of an end-use application. All materialsof an unknown end use application will normally be run in anunbacked condition. When conditions of use are known, thespecimen exposed will consist of the plastic material beingevaluated plus suitable backing materia
34、ls to conform to pro-jected practice. The effect of backing is highly significant andcontributes to the degradation as a function of reflectance, heatabsorption, moisture retention, etc. It shall always be used inrelation to an end-use system rather than as a standardmounting method.7.3 The use of a
35、t least three replicates of each experimentalmaterial being evaluated is recommended in order to accountfor variability.7.4 The total number of specimens will be determined bythe removal schedule and number of replicates plus filespecimens. These file specimens shall be retained at conditionsof 23.0
36、 6 5C and 50 6 20 % relative humidity. They shall bekept in a storage cabinet or covered with inert wrapping toexclude light exposure during the exposure period.8. Test Sites8.1 Weathering racks shall be located in cleared areas,preferably at a suitable number of climatologically differentsites repr
37、esenting the variable conditions under which theplastic product will be used. Climatological variations withinthese areas may include those represented by desert, seashore(salt air), industrial locations, tropical, and subtropical regions,plus areas exhibiting a wide range in solar radiant energy. T
38、hearea beneath and in the vicinity of the weathering racks shouldbe typical of the ground cover in that climatological area. Indesert areas in which sand, rock or bare earth is the prevailingground cover, coarse gravel is recommended to prevent abra-sion and significant dust accretion due to wind-bl
39、own sand(Note 6). The ground cover should be low-cut grass in mosttemperate, tropical, and subtropical areas.NOTE 6Sand as a ground cover may be desirable where the abrasiveeffects of exposure to wind-blown sand is a part of the desired exposure.9. Exposure Stages9.1 Use one of the following methods
40、 to specify theexposure stages at which changes in properties of test speci-mens are determined:NOTE 7The same exposure stage (by whichever method is used) willnot necessarily give the same changes in properties of the test specimen atdifferent exposure sites. The exposure stages must be regarded as
41、providing only a general indication of the degree of exposure, and theresults should always be considered in terms of characteristics of theexposure site as well.9.2 Exposure TimeSpecify the duration of the exposure interms of months (1, 3, 6, 12, 15, etc.) or years (1, 1.5, 2, 3, 4,5, etc.), unless
42、 otherwise instructed.NOTE 8The results for exposure stages of less than one year willdepend on the season of the year in which the exposure was made. Forinstance, summer exposures are generally more severe than winterexposures. Seasonal effects are averaged in exposures of several years.9.2.1 If re
43、quired, report the total solar radiant exposure andtotal solar UV radiant exposure that has been measured byradiometers positioned at the same tilt and azimuth angle as thetest specimens.9.3 Solar-Radiation MeasurementsSince solar radiation isone of the most important factors in the deterioration of
44、 plasticsduring weathering exposure, exposure stages may be defined interms of the amount of radiation received by the specimens.Aninherent limitation in solar-radiation measurements is that theydo not reflect the effects of variations in temperature andmoisture exposure, which can often be as impor
45、tant as solarradiation.FIG. 2 Suitably Mounted Specimens on a Plate HolderD1435 1339.3.1 Total Solar IrradianceMeasure the total solar irra-diance using solar-radiation measuring instrumentation as de-scribed in 5.4.2. Total solar radiant exposure shall be expressedin MJ/m2.9.3.2 Total Ultraviolet I
46、rradianceMeasure the total solar-ultraviolet irradiance using ultraviolet-measuring instrumenta-tion as described in 5.4.2. Total solar-ultraviolet radiant expo-sure shall be expressed in MJ/m2. This is the recommendedmethod for determining exposure stages when polymer degra-dation is being evaluate
47、d. Table 1 shows typical UV radiantexposures for 12 months in subtropical and desert climates.NOTE 9The average UV radiant exposures shown for subtropical anddesert climates are based on several years of measurement in these testenvironments. The actual yearly values may vary widely from Table 1.9.3
48、.2.1 Total solar radiant exposure (in MJ/m2) must also bemeasured and reported for each exposure stage defined by UVradiant exposure.9.3.3 Specified Narrow-Band Ultraviolet IrradianceTheUV irradiance in specified narrow-wavelength intervals (orbands) that conform closely to the wavelengths to which
49、thematerial is most sensitive may also be used to follow theexposure stages.10. Procedure10.1 Mark the test and control specimens to be exposed withan identifying number, letter, or symbol so that they may beidentified readily after exposure. Specimen marking shall be inaccordance with Practice G147 and shall be such that there isno interference with either the exposure or the subsequenttesting. (Preferably, mark both specimen and specimen holderon the side not exposed to weather, as advanced weathering canobscure even deeply scribed marks.)10
