1、Designation: C732 17Standard Test Method forAging Effects of Artificial Weathering on Latex Sealants1This standard is issued under the fixed designation C732; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisio
2、n. A number in parentheses 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 U.S. Department of Defense.1. Scope1.1 This test method covers a laboratory procedu
3、re for thedetermination of aging effects of artificial weathering on latexsealants.1.2 The values stated in metric (SI) units are to be regardedas the standard. The values given in parentheses are forinformation only.1.3 This standard does not purport to address all of thesafety concerns, if any, as
4、sociated with its use. It is theresponsibility 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 1Currently there is no ISO standard similar to this test method.2. Referenced Documents2.1 AS
5、TM Standards:2C717 Terminology of Building Seals and SealantsC1442 Practice for Conducting Tests on Sealants UsingArtificial Weathering Apparatus3. Terminology3.1 Definitions:3.1.1 Definitions of the following terms are found in Ter-minology C717: adhesive failure (loss of adhesion); latexsealant; s
6、ealant, standard conditions.4. Summary of Test Method4.1 The sealant is placed in a specially constructed wood-and-aluminum fixture (referred to as a “channel panel”) andexposed for intervals of 500 h to specified alternate wet and drycycles in an accelerated weathering unit, then periodicallyexamin
7、ed for evidences of deterioration.5. Significance and Use5.1 Accelerated weathering exposure serves to indicatelong-term exterior durability of the sealant. In this test method,durability is tested when the sealant is used with wood oraluminum.6. Apparatus6.1 Accelerated Weathering DeviceOne of the
8、units asdescribed in Practice C1442. Because of differences in spectralpower distributions of the exposure sources and exposureparameters used in the different types of devices described inPractice C1442, test results may differ with the type ofaccelerated weathering device. Choice of type of device
9、 shallbe by mutual agreement among the interested parties.6.2 Channel Panel attached to a Sample Holder as shown inFig. 1.6.3 Knife, for tooling.7. Sampling7.1 Use the sealant to be tested directly from the containeras commercially supplied by the manufacturer.8. Test Specimens8.1 Prepare two 25 by
10、70 by 175-mm (1 by 234 by 7-in.)wood-and-aluminum channel panels as shown in Fig. 1, usingthe following materials:8.1.1 Exterior Fir Plywood, with a water-resistant thermosetglue such as urea or melamine-formaldehyde type.8.1.2 Ponderosa Pine Sapwood, white kiln dried and free ofknots or imperfectio
11、ns.8.1.3 Aluminum Alloy 6063-T5 or 6061-T6, clear, anodizeda minimum of 30 min over a scale-free finish.8.1.4 Polyethylene Bond-Breaker of low-density film ap-proximately 5 mils (0.13 mm) thick.8.1.5 Screws and Nails, zinc-coated or nonrusting type.8.2 Using a gun or knife, completely fill the two 7
12、 by13-mm (14 by12-in.) channels in both panels with sealant,striking off the excess from the top and ends so that it is flushwith the panel surfaces.NOTE 2The length dimension of the channel may be reduced asneeded to accommodate the specimen holder requirements of the artificial1This test method is
13、 under the jurisdiction ofASTM Committee C24 on BuildingSeals and Sealantsand is the direct responsibility of Subcommittee C24.40 onWeathering.Current edition approved Jan. 1, 2017. Published February 2017. Originallyapproved in 1972. Last previous edition approved in 2012 as C732 06(2012). DOI:10.1
14、520/C0732-17.2For 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.Copyright ASTM International, 100 Barr Harbor Dr
15、ive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations i
16、ssued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1weathering device available for use.9. Conditioning9.1 Condition both specimens for 7 days at standard condi-tions.10. Procedure10.1 Secure one or more test specimen(s) in the artificialweathering unit and cycle for i
17、ntervals of 500 h, beginningwith the start of the light cycle. Refer to Practice C1442 for theartificial weathering unit operating conditions. Expose speci-mens in the xenon arc device for a minimum of 500 h at anirradiance level of 0.51 W/(m2 nm) at 340 nm. The radiantexposure for this is 918 kJ/(m
18、2 nm) at 340 nm. To determinethe exposure time required to obtain the same radiant exposureat other irradiance levels specified in Practice C1442, seeAnnex A1 in C1442.10.2 Maintain an unexposed file specimen at standard con-ditions until the accelerated weathering exposure is complete.10.3 After th
19、e test specimen has been exposed as specifiedin 10.1, remove it, allow it to cool to standard conditions.Examine it visually for wash-out, slump, cracking, loss ofadhesion to the wood or aluminum, and discoloration.11. Report11.1 Report the type and description of the laboratoryaccelerated weatherin
20、g device and the length of time the testMetric Equivalents Materials:in. mm in. mm 138 by 234 by 7-in. plywood14 6.434 19.1 114 by34 by 7-in. aluminum38 9.5 234 69.9 214 by12 by 7-in. ponderosa white pine12 12.7 7 177.8 1234 by 7-in. sheet untreated polyethylene3 Screws6 Nails1 Aluminum PanelFIG. 1
21、Channel Panel attached to a Sample HolderC732 172specimen(s) was/were exposed in the artificial weatheringdevice. Compare the exposed specimen with the unexposed filespecimen, and report any changes in wash-out, slump,cracking, loss of adhesion, or discoloration.12. Precision and Bias12.1 No stateme
22、nt is made about either the precision or thebias of this test method for measuring wash-out, slump,cracking, or loss of adhesion since the result merely stateswhether there is conformance to the criteria for successspecified in the procedure.13. Keywords13.1 artificial weathering; latex sealantASTM
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