1、Designation: C1681 14C1681 18Standard Test Method forEvaluating the Tear Resistance of a Sealant Under ConstantStrain1This standard is issued under the fixed designation C1681; 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method evaluates the impact of an induced tear on a sealant specimen that is dimensioned, cured accord
3、ing to theguidelines in Test Method C719 and then subjected to a constant strain. It is effective in differentiating between sealants that areused in dynamic joints subject to abrasion, punctures, tears, or combination thereof.1.2 Since this test method is for the evaluation of tear propagation, an
4、adhesive failure to the substrates provides no usable dataregarding tear propagation. This would be considered a failed test and that data would be discarded, or at least separated from theother data from specimens that did not experience an adhesive failure.1.3 This standard does not purport to add
5、ress all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.4 The committee with jurisd
6、iction over this standard is not aware of any comparable standards published by otherorganizations.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International S
7、tandards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C717 Terminology of Building Seals and SealantsC719 Test Method for Adhesion and Cohesion of Elastomeric Joint Sealants Under Cyclic Movem
8、ent (Hockman Cycle)3. Terminology3.1 DefinitionsRefer to Terminology C717 for definitions of the following terms used in this test method: castingspacer.standard, including but not limited to the following: adhesive failure, casting spacers, cohesive failure, separators, standardconditions.3.2 separ
9、atorsrigid spacers used to maintain a constant strain on the joint specimens during the testing period whilemaintaining parallel bond surfaces.4. Summary of Test Method4.1 Test specimens are fabricated and cured in accordance with Test Method C719. At the end of the 21-day cure period, aninduced tea
10、r is created in the specimens by making a cut with a sharp blade in the midpoint of the joint. The specimens are thenextended to a specified strain at both standard conditions and at 26 6 2C (15 6 3F). Propagation of the induced tear ismeasured at 0, 24 and 168 h.1 This test method is under the juri
11、sdiction of ASTM Committee C24 on Building Seals and Sealants and is the direct responsibility of Subcommittee C24.20 on GeneralTest Methods.Current edition approved June 1, 2014Jan. 1, 2018. Published July 2014January 2018. Originally approved in 2009. Last previous edition approved in 20092014 asC
12、1681-09.-14. DOI: 10.1520/C1681-14.10.1520/C1681-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This docu
13、ment is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as
14、appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 This test method is intended t
15、o determine if a joint that is subjected to a mechanically induced cut will resist tear propagationduring normal joint movement.Asealant with a high resistance to tear propagation will typically perform better than a sealant witha low resistance to tear propagation.6. Apparatus6.1 A device capable o
16、f extending the test specimens to the specified strain.6.2 Freezer, to maintain a constant temperature of 26C 6 2C.6.3 A suitable measuring device such as calipers able to measure the induced tears to 0.01 mm.6.4 #17 Knife Blade, 9 mm (0.37538 in.) wide.7. Reagents and Materials7.1 Spatulas, for use
17、 in applying the sealant.7.2 Caulking Gun, for extruding sealant from cartridges when applicable.7.3 Substratestwelve substrates, with minimum dimensions of 25 by 75 mm (1 by 3 in.) of the same finish are required foreach product to be tested. Glass is the default substrate, however as mentioned in
18、the scope, this is not an adhesion test, thereforethe sealant must exhibit excellent adhesion to the substrate. Other rigid substrates in the above noted dimension are acceptable.Substrate blocks or plates should be of adequate thickness or reinforced such that they do not flex or break during the t
19、esting.7.4 Casting SpacersMade from polytetrafluoroethylene (PTFE) or a suitable rigid material shall be used with each testspecimen to which the test sealant will not bond and will provide the appropriate joint dimensions and configurations. The Thecasting spacers provide joint dimensions of 12.7 b
20、y 12.7 by 50.8 mm (0.512 by 120.5 by 2 in.). See Fig. 5 in Test Method C719.7.5 Separators, to provide a constant strain on the specimen while maintaining parallel bond surfaces.7.6 Substrate Cleaning Material.7.7 Primer, if required on the substrates.7.8 A suitable measuring device, such as caliper
21、s, capable of measuring the induced cut in the sealant and additional changesin the cut to 0.01 mm.7.9 Marker, to identify the exact placement of the induced cut.7.10 A device which holds a #17 knife blade 9 mm (0.37538 in.) wide to induce the cut into the test specimens. See Fig. 1.8. Conditioning8
22、.1 Multicomponent SealantsPrepare six test specimens for each type of substrate that is to be used in the test. Aftermaintaining the unopened sample for at least 24 h at standard conditions, mix thoroughly for 5 min at least 250 g of base compoundwith the appropriate amount of curing agent. Extrude
23、the sealant 12.7 by 12.7 by 50.8 mm (0.512 by 120.5 by 2 in.) betweenFIG. 1 #17 BladeC1681 182parallel 25.4 by 76.2 mm (1 by 3 in.) surfaces of similar blocks or plates of the selected substrate. Use the appropriate castingspacer blocks spacers to form the proper size of the bead.Apply polyethylene
24、adhesive tape or any other suitable inert release agentto the inside surfaces of the spacers to prevent adhesion of the spacers to the sealant after cure. Use adhesive tape, rubber bands,or clamps to hold the test assembly together before and after filling it with the compound. In the case of a pour
25、able-type compound,use masking or any other suitable tape to retain the compound.8.2 Clean the test substrates using the methods suggested in Test Method C719. Fabricate the joints using the casting spacers.Mask off the top of the substrate edges, extrude the test sealant into the cavity taking care
26、 to fill in the all of the corners, tool thetop surface flat, and remove the masking tape.8.3 Single-Component SealantsPrepare six test specimens as described in 8.1 except that no mixing of components isrequired. Condition the sealed cartridge or bulk container at standard conditions at least 24 h
27、before use.8.4 Cure specimens made with multicomponent sealants for 14 days at standard conditions. During the second week of thecuring period, free the compound from the spacer blockscasting spacers at the ends and bottom without damaging the sealant bead.8.5 Cure specimens made with single-compone
28、nt sealants for a total of 21 days at standard conditions. See 8.6.1.8.6 Separate the casting spacers from the sealant as soon as practical during the curing period without damaging the sealant.Fourteen days is typically necessary.8.6.1 The producer may request conditions other than those specified
29、in 8.5 for the curing period of single-component sealantsprovided they meet the following requirements: (1) The curing period shall extend for 21 days; and (2) The temperature duringthe curing period shall not exceed 50C (122F).9. Procedure9.1 Within 8 h after the cure period (14 days for multicompo
30、nent or 21 days for single component products), mark the exactlocation for the induced cut with a permanent marker and then induce a cut, 9 mm (0.37538 in.) in length, and 12.7 mm (0.512in.) deep with the #17 knife blade. See Fig. 2. Make the cut as parallel as possible to the long direction of the
31、sample, locateddirectly on the midpoint and go perpendicularly through thickness of the sealant.9.2 Extend all specimens until the separation between the substrates provides the desired/specified extension (in the absence ofa specified strain, the sealant shall be strained to its Test Method C719 mo
32、vement capability). Apply this strain at a minimum rateof 3 mm per hour (0.12518 in. per hour). See Appendix X2.9.3 When the specimens have reached their specified extension, block the specimens with the appropriate separator and removefrom the extension device/machine. Do not remove separators for
33、the duration of test.9.4 Measure and record the length and width of the induced cut, immediately after the joints have been blocked at the specifiedstrain. This is the 0 hour data.9.5 Place three specimens in the freezer at 26 6 2C.9.6 Place three specimens at room temperature laboratory conditions.
34、9.7 After 24 and 168 h, measure and record the length and width of the induced cut on the top of the joint and record theobserved character of the tearing on the X and Y axis as noted in Fig. 3 (i.e., clean versus jagged, direction of the tear propagation,propagation of the tear at one or both ends
35、of the induced cut, etc.).10. Calculation or Interpretation of Results10.1 Report the change in length and width of the induced cut on the top of the joint in the sealant for each specimen alongthe X and Y axis noted below to the nearest 0.1 mm.10.2 Report the average change in dimension for length
36、and width for the room temperature and 26C conditions at 24 and168 h.10.2.1 (L1 + L2 + L3)/3 = Average change in Length.10.2.1.1 L24 h L0h = L24 h= Change in Length at 24 h.FIG. 2 Top View of Joint Showing the Placement of the Induced CutC1681 18310.2.1.2 L168 h L0h = L168 h = Change in Length at 16
37、8 h.10.2.2 (W1 + W2 + W3)/3 = Average change in Width.10.2.2.1 W24 h W0h = W24 h = Change in Width at 24 h.10.2.2.2 W168 h W0h = W168 h = Change in Width at 168 h.10.3 See Table 1 for a suggested table for taking data.11. Report11.1 Report the following information:11.1.1 Sealant used, color, manufa
38、cturers lot, type (single component or multicomponent) and rated movement capability perTest Method C719 as designated by the manufacturer,11.1.2 Actual dimensions of the joint and configuration,11.1.3 Cleaning method for each substrate,11.1.4 Description of the test substrate(s),11.1.5 Primer used
39、on specific substrates,11.1.6 Curing method and duration,11.1.7 Time of removal of casting spacers,11.1.8 Movement induced on the sealant during the test in % of original joint width,11.1.9 Method used to elongate the specimens to the desired strain and an estimated strain rate,11.1.10 Length and wi
40、dth of induced cut in each specimen after 0, 24, and 168 h for the room temperature and cold temperaturesand observations reported,11.1.11 Average change in length and width of the induced cut after 24 and 168 h at both the room temperature and 26Cconditioning, and11.1.12 Any other observations wort
41、hy of reporting.12. Precision and Bias12.1 A preliminary study was conducted with 7 laboratories and 3 different sealants. Problems encountered in measurementresulted in revisions to the standard. Only single sets of tests were run so repeatability also was not able to be determined. Asummary of the
42、 program is included in the Appendix.NOTE 1Measurements of the length of the cut (X axis) and width of cut (Y axis) are taken and reported at 0, 24, and 168 h.FIG. 3 Top View of a Joint that is Held Under a Fixed ExtensionTABLE 1 Suggested Table for Taking DataLength0 hWidth0 hLength24 hWidth24 hLen
43、gth168 hWidth168 hSpecimen 1 RTSpecimen 2 RTSpecimen 3 RTAverage Change RTafter 24 and 168 hNA NASpecimen 1 26CSpecimen 2 26CSpecimen 3 26CAverage Change 26Cafter 24 and 168 hNA NAC1681 18412.2 An interlaboratory program will be conducted after the test method is approved and in practice.13. Keyword
44、s13.1 constant strain testing; fixed extension; movement induced tear; sealantAPPENDIXES(Nonmandatory Information)X1. PILOT STUDYX1.1 Apilot study was conducted on the performance of the initial draft of the proposed standard. Seven laboratories participatedby testing three different materials. Thre
45、e samples of each material were to be prepared by each laboratory and stored at twodifferent temperatures during the test procedure.X1.2 The draft standard did not define the type and resolution of measurement devices. Some laboratories measured to the nearestmm while others provided readings to eit
46、her 0.1 or 0.01 mm. These later data sets showed variation in all sample sets while thosemeasured to the nearest mm (or half mm) showed virtually no differences in the samples tested to make up the test results.X1.3 Since the standard has been revised to require greater resolution in taking all obse
47、rvations, Table X1.1 only shows resultsfrom the laboratories that conducted more detailed tests. All readings are in millimeters and are the average of three samples.X1.4 The silicone and the urethane materials tested had a claimed movement capability rating of 25 %. The modified polyetherhad a clai
48、med movement rating of +10050 %. This is reflected in the initial width of cut noted in Table X1.1.TABLE X1.1 Results from Four LaboratoriesNOTE 1All measurements are in mm.Material LabInitialLengthof CutChange in Length1 DayChange in Length7 DayInitial Widthof CutChange in Width1 DayChange in Width
49、7 DaySilicone RT A 7.03 13.20 27.18 3.73 0.18 0.36B 10.95 4.27 13.00 3.55 0.35 0.86C 9.63 6.50 18.27 2.90 0.10D 8.47 1.28 5.27 2.96 0.19 0.08Urethane RT A 7.62 0.76 0.58 3.66 0.33 0.08B 10.45 0.45 0.37 3.93 0.09 0.23C 8.30 0.33 0.07 2.87 0.17D 8.68 0.02 0.51 2.90 0.36 0.23Modified Polyether RT A 7.90 0.99 2.12 10.84 3.02 2.16B 11.27 0.38 0.08 13.34 0.09 0.07C 10.67 0.37 0.27 13.47 0.17D 9.98 0.86 0.76 12.17 0.47 0.20Silicone 29C A 6.63 5.97 6.67 3.50 1.68 1.13B 9.94 0.49 8.23 4.18 0.01 0.54C 9.07
