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适用范围：<p>The tack-free time is a measure of the surface cure time and may generally be correlated to a variety of useful parameters such as the time interval before the sealant (<span class="italic">1</span>) resists damage by touch or light surface contact, (<span class="italic">2</span>) resists job-site or airborne dirt pick-up, (<span class="italic">3</span>) resists impinging rainfall.</p> <p>The tack-free time is sometimes used as an on-the-job quality assurance test. A quality product that is consistent and reproducible will generally fall within a maximum and minimum tack-free time.</p> <p>This test for tack-free time can be used at any temperature and humidity. It is important that if a sealant will be used in a climate quite different than the standard conditions called out in this test method, then those conditions be used to test the sealant.</p><p id="s00002">1.1 This test method covers a procedure for the determination of the tack-free time property of single- and multi-component <span class="italic">elastomeric sealants </span>commonly used for sealing, <span class="italic">caulking</span>, and <span class="italic">glazing </span>in buildings and related construction.</p> <p id="s00003">1.2 This test method is applicable to <span class="italic">self-leveling </span>and <span class="italic">non-sag </span>grades of <span class="italic">sealant</span>. Sealants requiring slight heating to facilitate extrusion from the cartridge or gun are also described by this test method. <p class="desc" id="N00001"> <span class="smallcap">Note</span> 18212;See Specification C 920<astmref rid="a00002"> for type and grade definitions.</p> </p> <p id="s00004">1.3 The values stated in metric units are to be regarded as the standard. The values given in parentheses are provided for information purposes only.</p> <p id="s00005">1.4 <span class="italic">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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.</span> <p class="desc" id="N00006"> <span class="smallcap">Note</span> 28212;Currently, there is no ISO standard similar to this specification.</p>