ASTM C734-15(R2019) pdf free download

ASTM C734-15(R2019) pdf free download.Standard Test Method for Low-Temperature Flexibility of Latex Sealants After Artificial Weathering
1. Scope
1.1 This test method covers a laboratory procedure for the determination of low-temperature flexibility of latex sealants after 500 h artificial weathering. 1.2 The values stated in metric (SI) units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability of regulatory limitations prior to use. NOTE 1- Currently there is no ISO standard similar to this test method. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology
3.1 Definitions- -Refer to Terminology C717 for definitions of the following terms used in this test method: adhesive failure, latex sealant, sealant, substrate, and standard condi- tions.
4. Summary of Test Method
4.1 A slab of the sealant is exposed, after drying, for a . minimum of 500 h in an artificial weathering unit, after which it is conditioned and flexed at-17士1 °C(0士2 °F).
5. Significance and Use
5.1 This test evaluates the flexibility of artificially weath- ered latex sealants in a low-temperature environment.
6. Apparatus
6.1 T3 Temper Alclad Aluminum Panels, three, each 76 by 153-mm (3 by 6-in.) of 16 to 24 gauge (1.29 to 0.511 mm). 6.2 Accelerated Weathering Device- _One of the units as described in Practice C1442. Because of differences in spectral power distributions of the exposure sources and exposure parameters used in the different types of devices described in Practice C1442， test results may differ with the type of accelerated weathering device. Choice of type of device shall be by mutual agreement among the interested parties. 6.3 Cold Box or Freezer: 6.4 Mandrel, Wood or Metal, 25 mm (1 in.) in diameter. 6.5 Template, consisting of a 3.2-mm (/8-in.) thick brass plate with a rectangular opening 38 by 127 mm (1%2 by 5 in.). 6.6 Spatula, metal.
7. Sampling
7.1 Take the sealant to be tested directly from the container as commercially supplied by the manufacturer.
8. Test Specimens
8.1 Prepare three test specimens as follows: 8.1.1 Center the template on an aluminum panel, fill it to excess with the sealant, and strike the excess off flush with the surface of the template with the metal spatula. 8.1.2 Cut around the perimeter of the sealant, next to the template, with the spatula, and carefully remove template. 9. Conditioning 9.1 Condition the three specimens for 2 days at standard conc ditic ions.
10. Procedure
10.1 Place the conditioned specimens in the artificial weath- ering unit and cycle them for a minimum of 500 h, beginning with the start of the light cycle. Refer to Practice C1442 for the artificial weathering unit operating conditions. Expose speci- mens in the xenon arc device for a minimum of 500 h at an irradiance level of 0.51 W(m2●nm) at 340 nm. The radiant exposure for this is 918 kJ/(m2 . nm) at 340 nm. To determine the exposure time required to obtain the same radiant exposure at other irradiance levels specified in Practice C1442, see Annex A1 in C1442. 10.2 Following artificial weathering exposure, place the specimens and the mandrel in a cold box maintained at-17土 1 °C(0士2°F) for4 h. 10.3 While still in the cold box, place each specimen in turn on the mandrel, with the aluminum plate next to the mandrel, and, without holding the sealant, bend the specimen 90° around the mandrel within 1 s.