1、Designation: D 1435 05Standard Practice forOutdoor Weathering of Plastics1This standard is issued under the fixed designation D 1435; 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 parenthese
2、s indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、 materials to weather.NOTE 1See Practice G24for 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
4、.3 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 theresponsibili
5、ty 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 877.2-1991, Method A, are technicallyequivalent.2. Referenced Documents2.1 ASTM Standards:2D 883 Terminology Relat
6、ing to PlasticsD 1600 Terminology for Abbreviated Terms Relating toPlasticsE 772 Terminology Relating to Solar Energy ConversionG7 Practice for Atmospheric Environmental ExposureTesting of Nonmetallic MaterialsG24 Practice for Conducting Exposures to Daylight Fil-tered Through GlassG84 Practice for
7、Measurement of Time-of Wetness onSurfaces Exposed to Wetting Conditions as inAtmosphericCorrosion TestingG113 Terminology Relating to Natural and ArtificialWeathering Tests of Nonmetallic MaterialsG 141 Guide forAddressing Variability in Exposure Testingof Nonmetallic MaterialsG 147 Practice for Con
8、ditioning and Handling of Nonme-tallic Materials for Natural and Artificial Weathering Tests2.2 ISO Standard:ISO 877.2-1991 Method A, Methods for Exposure to DirectWeathering, to Weathering Using Glass-Filtered Daylight,and to Intensified Weathering Using Fresnel Mirrors33. Terminology3.1 Definition
9、sFor definitions of technical terms pertain-ing to plastics used in this practice, see Terminologies D 883,D 1600, G 113, and E 772.4. Significance and Use4.1 Tests conducted in accordance with this practice areused to evaluate the stability of plastic materials when they areexposed outdoors. The re
10、lative 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, pollutants, and other factors. Itcannot be assumed, therefore, that results from one exposure ina single locat
11、ion 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 conditions are recommended.4.1.1 Because of year-to-year climatological variations, re-sults from a single exposur
12、e 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 of short-term exposure tests can provide anindication of relative outdoor performance, but they should notbe u
13、sed to predict the absolute long-term performance of a1This practice is under the jurisdiction ofASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.50 on Permanence Properties.Current edition approved March 1, 2005. Published March 2005. Originallyapproved in 1956. La
14、st previous edition approved in 1999 as D 1435 - 99.2For 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.3Availabl
15、e from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.material. The results
16、 of tests conducted for less than twelvemonths will depend on the particular season of the year inwhich they begin.5. Apparatus5.1 The test site shall conform to the requirements ofPractice G7. Unless otherwise specified, position exposureracks so that they face the equator. The angle of the exposur
17、erack relative to the horizontal can vary depending upon theend-use conditions that are being evaluated.NOTE 3Test sites at latitudes less than 23278 from 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-L
18、atitude RacksThese racks shall be adjustedsuch that the exposed surfaces are at an angle from thehorizontal corresponding exactly to the site latitude angle(Note 4).NOTE 4At-latitude exposure provides maximum annual total solar-radiant exposure at most non-subtropical sites. In most non-desert areas
19、,however, maximum annual ultraviolet-radiant exposure is provided byexposure at an angle of the latitude angle minus 10.5.1.2 45 RacksThese racks shall be adjusted such thatthe exposed surfaces of specimens are at an angle of 45 to thehorizontal.5.1.3 90 RacksThese racks shall be adjusted such thatt
20、he exposed surfaces of specimens are at an angle of 90 to thehorizontal.5.1.4 Horizontal 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 usuall
21、y preferred. However, plastic roofingmembranes, artificial turf, and other plastics that may be exposed athorizontal in their end-use condition should be exposed at 0 horizontal.5.1.5 Other-Angle RacksThese racks shall be adjustedsuch that the exposed surfaces of specimens are at a tilt anglemutuall
22、y agreed upon between the interested parties.5.2 Materials and Manner of ConstructionTest racks andhardware shall conform to the requirements of Practice G7andshall provide for attachment of specimens or holders of anyconvenient width and length. The structural members of thetest racks shall not con
23、stitute a backing to the specimens undertest unless it is used in relation to an end-use 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.
24、5.3 Specimen Holders:5.3.1 Most specimens under test will not be of an exact sizefor mounting 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
25、 evaluated unless it is used inrelation to an end-use system.5.3.2 The specimen holders 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 po
26、sition, yetis not constrained (that is, it is free to expand or contract withthermal changes, 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 sp
27、ecimens. The exposure aperture of each frameshall be of sufficient size to expose the entire test area of eachspecimen when sufficient specimens are contained.5.3.5 Plate HoldersThis type of holder is a universalpanel consisting of a slotted-aluminum plate on which electri-cal white glaze porcelain
28、insulators4are mounted at properpositions to affix various-sized specimens. The specimens aremounted in the grooves of the insulators at a fixed distance of11 mm from the slotted back plate. The insulators provide inertmounting while the slotted plate permits free circulation of airbehind the specim
29、en. This method of mounting is shown inFig. 1.5.4 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
30、.5.4.2 Instruments Used 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 wi
31、th the pertinentconsiderations outlined in Guide G 141.7. 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 prop
32、erty, or theymay be larger specimens from which smaller specimens forevaluation may be cut. Exposure test specimens should belarge enough that mounting edges may be removed whereevaluation test results would otherwise be affected.7.2 As far as practical, exposure test specimens shall simu-late servi
33、ce 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 materials to conform to pro-jected pra
34、ctice. 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.4A satisfactory insulator for this purpose is C
35、atalog No. 615160, Special No. 6Knob, dry-process, porcelain insulator, available from Porcelain Products, Carey,OH.D14350527.3 The use of at least two replicates of each experimentalmaterial being evaluated is recommended in order to allow forvariability.7.4 The total number of specimens will be de
36、termined bythe removal schedule and number of replicates plus filespecimens. These file specimens shall be retained at conditionsof 23.0 6 5C and 50 6 20 % relative humidity. They shall becovered with inert wrapping to exclude light exposure duringthe exposure period.8. Test Sites8.1 Weathering rack
37、s shall be located in cleared areas,preferably at a suitable number of climatologically differentsites representing the variable conditions under which theplastic product will be used. Climatological variations withinthese areas may include those represented by desert, seashore(salt air), industrial
38、 locations, tropical, and subtropical regions,plus areas exhibiting a wide range in solar radiant energy. Thearea beneath and in the vicinity of the weathering racks shouldbe typical of the ground cover in that climatological area. Indesert areas in which sand is the prevailing ground cover,coarse g
39、ravel is recommended to prevent abrasion and signifi-cant dust accretion due to wind-blown sand (Note 6). Theground cover should be low-cut grass in most temperate,tropical, and subtropical areas.NOTE 6Sand as a ground cover may be desirable where the abrasiveeffects of exposure to wind-blown sand i
40、s a part of the desired exposure.9. Exposure Stages9.1 Use one of the following methods 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 o
41、f the test specimen atdifferent exposure sites. The exposure stages must be regarded asproviding 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 exposu
42、re interms of months (1, 3, 6, 12, 15, etc.) or years (1, 1.5, 2, 3, 4,5, etc.), unless 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 w
43、interexposures. Seasonal effects are averaged in exposures of several years.9.2.1 If required, 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 Measur
44、ementsSince solar radiation isone of the most important factors in the deterioration of 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
45、 effects of variations in temperature andmoisture exposure, which can often be as important as solarradiation.9.3.1 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/m
46、2.9.3.2 Total Ultraviolet IrradianceMeasure 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 deg
47、ra-dation is being evaluated. Table 1 shows typical UV radiantFIG. 1 Suitably Mounted SamplesTABLE 1 Typical UV Radiant Exposures for 12 Months inSubtropical and Desert ClimatesExposure Time(Months)Average UV Radiant Exposure(MJ/m2, 295 to 385 nm)Subtropical Climate(at 5)Desert Climate(at latitude)1
48、2 308 333D1435053exposures 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 1.9.3.2.1 Total solar r
49、adiant 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 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 inacco
