1、Designation: C734 15Standard Test Method forLow-Temperature Flexibility of Latex Sealants After ArtificialWeathering1This standard is issued under the fixed designation C734; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers a laboratory procedure for thedetermination of low-temperature flexibility of latex sealan
3、tsafter 500 h artificial weathering.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, associated with its use. It is theresponsibility
4、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 ASTM Standards:2C717 Terminology of Building Seal
5、s and SealantsC1442 Practice for Conducting Tests on Sealants UsingArtificial Weathering Apparatus3. Terminology3.1 DefinitionsRefer to Terminology C717 for definitionsof the following terms used in this test method: adhesivefailure, latex sealant, sealant, substrate, and standard condi-tions.4. Sum
6、mary of Test Method4.1 A slab of the sealant is exposed, after drying, for aminimum of 500 h in an artificial weathering unit, after whichit is conditioned and flexed at 17 6 1C (0 6 2F).5. Significance and Use5.1 This test evaluates the flexibility of artificially weath-ered latex sealants in a low
7、-temperature environment.6. Apparatus6.1 T3 Temper Alclad Aluminum Panels, three, each 76 by153-mm (3 by 6-in.) of 16 to 24 gage (1.29 to 0.511 mm).6.2 Accelerated Weathering DeviceOne of the units asdescribed in Practice C1442. Because of differences in spectralpower distributions of the exposure s
8、ources 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 shallbe by mutual agreement among the interested parties.6.3 Cold Box or Freezer.6.4 Mandrel, Wood or Metal
9、, 25 mm (1 in.) in diameter.6.5 Template, consisting of a 3.2-mm (18-in.) thick brassplate with a rectangular opening 38 by 127 mm (112 by 5 in.).6.6 Spatula, metal.7. Sampling7.1 Take the sealant to be tested directly from the containeras commercially supplied by the manufacturer.8. Test Specimens8
10、.1 Prepare three test specimens as follows:8.1.1 Center the template on an aluminum panel, fill it toexcess with the sealant, and strike the excess off flush with thesurface of the template with the metal spatula.8.1.2 Cut around the perimeter of the sealant, next to thetemplate, with the spatula, a
11、nd carefully remove template.9. Conditioning9.1 Condition the three specimens for 2 days at standardconditions.10. Procedure10.1 Place the conditioned specimens in the artificial weath-ering unit and cycle them for a minimum of 500 h, beginningwith the start of the light cycle. Refer to Practice C14
12、42 for the1This test method is under the jurisdiction ofASTM Committee C24 on BuildingSeals and Sealants and is the direct responsibility of Subcommittee C24.40 onWeathering.Current edition approved June 1, 2015. Published July 2015. Originally approvedin 1972. Last previous edition approved in 2012
13、 as C732 06(2012). DOI:10.1520/C0734-15.2For 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 Intern
14、ational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1artificial 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/(m2
15、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 Following artificial weathering exposure, place thespecimens and the mandrel in a cold box maintained at 17 61C (0 6 2F) for 4 h.
16、10.3 While still in the cold box, place each specimen in turnon the mandrel, with the aluminum plate next to the mandrel,and, without holding the sealant, bend the specimen 90 aroundthe mandrel within 1 s.10.4 Visually examine the specimens after bending, forcracking of the sealant or adhesive failu
17、re to the aluminum, orboth.11. Report11.1 Report the type and description of the laboratoryaccelerated weathering device, the length of time the testspecimens were exposed in the artificial weathering device andwhether the sealant cracks through to the substrate, or failsadhesively to the aluminum p
18、anel.12. Precision and Bias12.1 No statement is made about either the precision or biasof this test method for measuring low temperature flexibilitysince the result states merely whether there is conformance tothe criteria for success specified in the procedure.13. Keywords13.1 artificial weathering
19、; flexibility; latex sealantASTM International takes no position respecting the validity of any patent rights 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 infr
20、ingement of such rights, are entirely their own responsibility.This standard is subject to revision at any time 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 standa
21、rd or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive 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 vie
22、ws known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 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 contacti
23、ng 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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 152
