1、Designation: C 734 06Standard Test Method forLow-Temperature Flexibility of Latex Sealants After ArtificialWeathering1This standard is issued under the fixed designation C 734; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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 covers a laboratory procedure for thedetermination of low-temperature flexibility of latex sea
3、lantsafter 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 theresponsibili
4、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 1Currently there is no ISO standard similar to this test method.2. Referenced Documents2.1 ASTM Standards:2C 717 Terminology of Building
5、Seals and SealantsC 1442 Practice for Conducting Tests on Sealants UsingArtificial Weathering Apparatus3. Terminology3.1 DefinitionsRefer to Terminology C 717 for definitionsof the following terms used in this test method: adhesivefailure, latex sealant, sealant, substrate.4. Summary of Test Method4
6、.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-temperature environ
7、ment.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 C 1442. Because of differences in spectralpower distributions of the exposure sources and exposure
8、parameters used in the different types of devices described inPractice C 1442, 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, 25 mm (1 in.) in
9、 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 Specimens8.1 Prepare three t
10、est 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, and carefully remov
11、e 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 C 1442 for theartific
12、ial 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 nm) at 340 nm. To determine1This test method is under the jurisdiction ofASTM Committee C24 on Build
13、ingSeals and Sealants and is the direct responsibility of Subcommittee C 24.40 onWeathering.Current edition approved Sept. 1, 2006. Published September 2006. Originallyapproved in 1972. Last previous edition approved in 2001 as C 732 01.2For referenced ASTM standards, visit the ASTM website, www.ast
14、m.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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the expos
15、ure time required to obtain the same radiant exposureat other irradiance levels specified in Practice C 1442, seeAnnex A1 in C 1442.10.2 Following artificial weathering exposure, place thespecimens and the mandrel in a cold box maintained at 17 61C (0 6 2F) for 4 h.10.3 While still in the cold box,
16、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 failure to the aluminum, orboth.11. Rep
17、ort11.1 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 panel.12. Precision and Bias12.1 No
18、 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; flexibility; latex sealantASTM I
19、nternational 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 infringement of such rights, are entir
20、ely 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 standard or for additional standardsand
21、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 views known to the ASTM Committee on
22、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 contacting 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).C734062
