1、Designation: C 1501 04Standard Test Method forColor Stability of Building Construction Sealants asDetermined by Laboratory Accelerated WeatheringProcedures1This standard is issued under the fixed designation C 1501; the number immediately following the designation indicates the year oforiginal adopt
2、ion or, in 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.1. Scope1.1 This test method describes laboratory acceleratedweathering procedures u
3、sing either fluorescent ultraviolet orxenon arc test devices for determining the color stability ofbuilding construction sealants.1.2 Color stability rankings provided by these two proce-dures may not agree.1.3 The values stated in SI units are to be regarded as thestandard. Values given in parenthe
4、ses are for information only.1.4 There is no equivalent ISO standard for this test method.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practic
5、es and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 717 Definitions of Terms Relating to Building Seals andSealantsC 1442 Practice for Conducting Tests on Sealants usingArtificial Weathering ApparatusD 1729 Practice for Visual Evalu
6、ation of Color Differencesof Opaque MaterialsD 2244 Test Method for Calculation of Color Differencesfrom Instrumentally Measured Color CoordinatesE 284 Terminology of AppearanceG 113 Terminology Relating to Natural and ArtificialWeathering tests for Nonmetallic MaterialsG 151 Practice for Exposing N
7、onmetallic Materials in Ac-celerated Test Devices That Use Laboratory Light SourcesG 154 Practice for Operating Fluorescent Light Apparatusfor UV Exposure of Nonmetallic MaterialsG 155 Practice for Operating Xenon Arc Light Apparatusfor Exposure of Nonmetallic Materials2.2 CIE Documents:CIE Publicat
8、ion Number 85: 1989, Technical Report-SolarSpectral Irradiance33. Terminology3.1 DefinitionsDefinitions of the following terms arefound in ASTM standard C 717: compound, cure, sealant, andsubstrate. Definitions of the following terms are found inASTM standard G 113: sample, file specimen, control ma
9、terial,fluorescent ultraviolet lamps, xenon arc, irradiance, radiantexposure, spectral power distribution, solar radiation-ultraviolet, solar radiation-visible.4. Summary of Test Method4.1 Specimens for this procedure are prepared in which thesealant to be tested adheres to flat aluminum panels. Whi
10、le anysurface can be specified and used, this test method wasdeveloped with aluminum panels. At least four replicates ofeach sealant being tested are required. After curing, onereplicate of each sealant being tested is retained as a filespecimen and at least three replicates are exposed to actinicra
11、diation, heat and moisture. At the end of the exposure period,the test sealant is examined for color change by comparison tothe unexposed file specimen.4.2 As recommended in ASTM G 151 Section 4.2, unlessseveral test sealants are exposed to determine their relativecolor stabilities, one or two contr
12、ol sealants of similar compo-sition and construction to the test specimen and having knowncolor stability should be exposed simultaneously with the testspecimen to rank the color stability of the latter compared withthe color stability of the control(s).5. Significance and Use5.1 This test method is
13、 intended to induce color changes insealants, as well as their constituent pigments, associated withend-use conditions, including the effects of sunlight, moisture,and heat. The exposures used in this test method are not1This test method is under the jurisdiction of ASTM Committee C24 on BuildingSea
14、ls and Sealants and is the direct responsibility of Subcommittee C24.40 onWeathering.Current edition approved Aug. 1, 2004. Published October 2004. Originallyapproved in 2001. Last previous edition approved in 2001 as C 150101.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orc
15、ontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3CIE Central Bureau, Vienna, Kegelgasse 27, A-1030 Wien, Austria1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, Wes
16、t Conshohocken, PA 19428-2959, United States.intended to simulate the color change of a sealant caused bylocalized weathering phenomena, such as atmospheric pollu-tion, biological attack, and saltwater exposure.5.2 When conducting exposures in devices that use labora-tory light sources, it is import
17、ant to consider how well theartificial test conditions will reproduce property changes andfailure modes associated with end-use environments for thesealant being tested. Information on the use and interpretationof data from accelerated exposure tests is provided in ASTMG 151.5.3 When this test metho
18、d is used as part of a specification,exact procedure, test conditions, test duration and evaluationtechnique must be specified. Results obtained between the twoprocedures may vary, because the spectral power distributionof the light sources (fluorescent UV and xenon arc) differ.Sealants should not b
19、e compared to each other based on theresults obtained in different types of apparatus.5.4 These devices are capable of matching ultraviolet solarradiation reasonably well. However, for sealants sensitive tolong wavelength UV and visible solar radiation, the absence ofthis radiation in the fluorescen
20、t UV apparatus can distort colorstability ranking when compared to exterior environmentexposure.NOTE 1Refer to Practices G 151 for full cautionary guidance regard-ing laboratory weathering of non-metallic materials.6. Apparatus6.1 Aluminum PanelsApply sealant to four aluminumpanels, alloy 3003 H14,
21、dimensions, 152mm by 76mm by0.64mm thick (6 by 3 by 0.025 inches thick), using rectangularBrass Frame described in 6.3. Other substrate materials areacceptable when specified.6.2 Spatula, steel, about 150 mm (6 inches) long.6.3 Rectangular Brass Frame, with outside dimensions ofapproximately 152mm b
22、y 76mm, and inside dimensions 75mmby 65mm by 3.0mm (3 inches long by 2.5 inches wide by 0.125inches deep).6.4 Thin Bladed Knife.6.5 Color Evaluation Apparatus:6.5.1 Lighting Equipment, to evaluate color difference ac-cording to D 1729; or,6.5.2 Spectrophotometer, complying with Practice E 1164;or,6.
23、5.3 Colorimeter, complying with Test Method D 2244.6.6 Cleaning Solvent, isopropyl alcohol.6.7 Test ChamberChoice of type of apparatus shall be bymutual agreement among the interested parties. Because ofdifferences in test conditions, test results may differ with thetype of apparatus used. Consult P
24、ractices G 154 and G 155 fordifferences in the spectral power distributions of the exposuresources and Practice C 1442 for the differences in test param-eters in the two types of apparatus specified. The test cycleshave been used by historical convention and may not ad-equately simulate the effects
25、of outdoor exposure of sealants.Other cycles can be used by mutual agreement of all concernedparties.6.7.1 Fluorescent UV/Condensation ApparatusOperatethe device in accordance with the procedure in PracticeC 1442, Section 7.3.6.7.2 Xenon Arc Light ApparatusOperate the device inaccordance with the pr
26、ocedure in Practice C 1442, Section 7.2.NOTE 2CIE Publication No. 85-1989 provides data on solar spectralirradiance for typical atmospheric conditions, which can be used as a basisfor comparing laboratory light sources with daylight. For example, globalsolar irradiance is 0.68 W/(m2 nm) at 340 nm as
27、 presented in CIE 85 table4.6.7.3 MoistureThe test specimens may be exposed tomoisture in the form of water spray, condensation, immersion,or high humidity as agreed on by the mutual parties. Refer toPractice G 151 Section 6.6 for discussion of the various formsof moisture in accelerated test device
28、s.7. Procedure7.1 Condition sufficient sealant in an original closed con-tainer for at least 24 hours at standard conditions. Standardconditions are a temperature of 23 6 2C (73 6 3.6F) andrelative humidity of 50 6 5 %, away from light.7.2 Prepare at least four sealant test specimens and at leastfou
29、r of the control material, if used, on aluminum panels. Cleanthe aluminum panels using cleaning solvent. Allow solvent todry before applying sealant.7.3 Position the brass frame on the aluminum panel andoverfill the entire frame with conditioned sealant. Strike off flatusing the spatula. Immediately
30、 separate the sealant from theframe by running a thin bladed knife along the inside of theframe. Lift the frame from the aluminum panel.7.4 Cure the test specimens at standard conditions for 21days. Other conditions for curing are acceptable when specifiedprovided they meet the following requirement
31、s: 1) the curingperiod shall not exceed 21 days, and 2) the temperature duringthe curing period shall not exceed 50C (122F). Keep one testspecimen as an unexposed file specimen and store at standardconditions.7.5 Place at least three of the cured specimens and thecontrol material if used, in the wea
32、thering apparatus with thesealant surface facing the radiation source and positioned at thespecified distance from the source. Specimens should beconfined to an exposure area in which the irradiance is at least90 % of the irradiance at the center of the exposure area.Unless it is known that irradian
33、ce uniformity meets thisrequirement, use one of the procedures described in PracticeG 151, Section 5.1.4 to ensure equal radiant exposure on allspecimens or compensation for differences within the exposurechamber. If the specimens do not completely fill the racks, fillthe empty spaces with blank met
34、al panels to maintain the testconditions within the chamber.7.6 Apparatus shall be operated continuously. However, ifthe test needs to be interrupted to perform routine maintenanceor inspection, it should be during a dry period.7.7 Expose the specimens for a mutually agreed uponspecified duration in
35、 hours or radiant energy. Because of theoption of operating the xenon arc apparatus at an irradiancelevel of 0.35 W/(m2.nm) at 340 nm as well as 0.51 W(m2.nm)at 340 nm, test duration is specified in terms of radiant energy.C1501042The time in hours at the irradiance level used is determinedaccording
36、 to the formula in Annex A1.2.1 in Practice C 1442.Evaluate specimens in the fluorescent UV apparatus at 1,000-hour exposure intervals, where applicable. Evaluate specimensin the xenon arc apparatus operated at an irradiance level of0.51 W/(m2.nm) at 340 nm at intervals of 1835 kJ/(m2.nm) at340 nm.
37、The minimum exposure duration shall be sufficient toproduce a statistically significant change in color in the leastcolor stable building construction sealant.7.8 After artificial weathering, condition the samples at 236 2C (73 6 4F) and 50% 6 5% relative humidity for at leasttwo hours before color
38、evaluation.7.9 The color measuring instrument should be set up to readin the CIE L*a*b* color scale with illuminant C or D65 and10 observer, specular component included. Measure the colorvalues of each test specimen and control, if used, prior toexposure and after each exposure. The edges of the spe
39、cimensmay be trimmed to compensate for shrinkage and provide asecure fit in the color-measuring instrument. Make a minimumof three measurements per specimen, moving or rotating thespecimen so as to measure different areas. Using the CIELABcolor-difference formula described in Test Method D 2244,calc
40、ulate DE*abbetween each exposed specimen and its filespecimen (unexposed counterpart).7.10 As an alternative to the instrumental color measure-ment procedure in 7.9 above, evaluate color differences be-tween exposed and unexposed file specimen sealant usingD 1729 Practice for Visual Evaluation of Co
41、lor Differences ofOpaque Materials.7.11 Pass/fail evaluations based on either absolute colorchange after a specified exposure period or comparativestabilities, should be made using the variability determined forthe combined exposure and color measurement so that statis-tically significant pass/fail
42、judgements can be made.7.12 The duration of exposure required to obtain a specifiedlevel of color difference can be determined by interpolationfrom a plot of DE*abversus time or cumulative radiantexposure. This approach permits the rate of color change to bedetermined and weatherability to be more a
43、ccurately evaluatedthat in tests based on change after a specified exposure period.8. Report8.1 In addition to the items specified in the Report section ofStandard Practice G 151, the report shall include the followingfor each sample tested:8.1.1 Type, manufacturer and model of laboratory acceler-at
44、ed weathering apparatus,8.1.1.1 Irradiance level and actual time (number of hours) inweathering apparatus.8.1.2 Identification of sealant specimen tested, and controlsused, if any.8.1.3 Sealant cure conditions employed,8.1.4 Qualitative visual color differences as specified inD 1729 or quantitative
45、color difference as specified in D 2244.8.1.5 Variations, if any, from the specified test procedure.9. Precision and Bias9.1 PrecisionRound robin testing was performed by fourlaboratories using three different sealants and both exposureprocedures4. Precision statements for DE*ab(dEab), colorchange o
46、f sealants, tested both by Fluorescent UV/Condensation Apparatus and Xenon Arc Light Apparatus arepresented separately below.9.1.1 Standard test method for color change, DE*ab(dEab),of sealants under laboratory accelerated weathering conditionsfor Procedure G 154 Standard Practice for Operating Fluo
47、res-cent UV/Condensation Apparatus.9.1.1.1 Repeatability, I (r)The average repeatability(within a given laboratory) for 3 materials tested by 4 labora-tories is 2.722 for dEab. In future use of this test method, thedifference between two test results obtained in the samelaboratory on the same materi
48、al will be expected to exceed2.722 for dEab only about 5 percent of the time.9.1.1.2 Reproducibility, I (R) The average reproducibility(between given laboratories) for 3 materials tested by 4laboratories is 3.561 for dEab. In future use of this test method,the difference between two test results obt
49、ained in a differentlaboratory on the same material will be expected to exceed3.561 for dEab only about 5 percent of the time.9.1.2 Standard test method for color change, DE*ab(dEab),of sealants under laboratory weathering conditions for Proce-dure G 155 Standard Practice for Operating Xenon Arc LightApparatus.9.1.2.1 Repeatability, I (r) The average repeatability(within a given laboratory) for 3 materials tested by 4 labora-tories is 1.035 for dEab. In future use of this test method, thedifference between two test results obtained in the samelaboratory on the same
