1、Designation: C679 03 (Reapproved 2009)1C679 15Standard Test Method forTack-Free Time of Elastomeric Sealants1This standard is issued under the fixed designation C679; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、 revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1 NOTEThe term “standard conditions was added to
3、 3.1 in March 2009.1. Scope1.1 This test method covers a procedure for the determination of the tack-free time property of single- and multi-componentelastomeric sealants commonly used for sealing, caulking, and glazing in buildings and related construction.1.2 This test method is applicable to self
4、-leveling and non-sag grades of sealant. Sealants requiring slight heating to facilitateextrusion from the cartridge or gun are also described by this test method.NOTE 1See Specification C920 for type and grade definitions.1.3 The values stated in metric units are to be regarded as the standard. The
5、 values given in parentheses are provided forinformation purposes only.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine th
6、e applicability of regulatorylimitations prior to use.NOTE 2Currently, there is no ISO standard similar to this specification.2. Referenced Documents2.1 ASTM Standards:2C717 Terminology of Building Seals and SealantsC920 Specification for Elastomeric Joint Sealants3. Terminology3.1 DefinitionsSee Te
7、rminology C717 for definitions of the following terms used in this test method: caulking, compound,cure, elastomeric, glazing, non-sag sealant, sealant, self-leveling sealant, and standard conditions.4. Summary of Test Method4.1 The test consists of lightly touching a surface of a curing sealant wit
8、h a polyethylene film at regular intervals until the sealantdoes not attach itself to the film and the film appears clean when peeled from the surface.4.2 More specifically a strip of polyethylene film is placed on the surface of the curing sealant and a 30-g (1.06-oz) weight isplaced on the film.Th
9、e weight is left in place for 30 s, then removed and the polyethylene strip is removed and examined for sealantattachment to the film. The length of time from when the sealant was first applied and tooled into the template until the time thesealant is no longer picked up by the film is called tack-f
10、ree time.4.3 With some sealants, interpretation of the end point is confusing in that a very thin film of sealant or oil will transfer to thefilm. For consistency of data, record the point where the bulk sealant is no longer transferred to the plastic but ignore the very thinuniform film of sealant
11、or the plasticizer transferred to the plastic test strip.1 This test method is under the jurisdiction of ASTM Committee C24 on Building Seals and Sealants and is the direct responsibility of Subcommittee C24.20 on GeneralTest Methods.Current edition approved Jan. 1, 2009July 1, 2015. Published March
12、 2009September 2015. Originally approved in 1971. Last previous edition approved in 20032009 asC679 03.C679 091. DOI: 10.1520/C0679-03R09E01.10.1520/C0679-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of AS
13、TM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document 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 p
14、ossible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as 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,
15、 West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 The tack-free time is a measure of the surface cure time and may generally be correlated to a variety of useful parameterssuch as the time interval before the sealant (1) resists damage by touch or light surface contact, (2)
16、 resists job-site or airborne dirtpick-up, (3) resists impinging rainfall.5.2 The tack-free time is sometimes used as an on-the-job quality assurance test. A quality product that is consistent andreproducible will generally fall within a maximum and minimum tack-free time.5.3 This test for tack-free
17、 time can be used at any temperature and humidity. It is important that if a sealant will be used in aclimate quite different than the standard conditions called out in this test method, then those conditions be used to test the sealant.6. Apparatus6.1 Cabinet or Room, capable of maintaining a tempe
18、rature of 23 6 2C (73.4 6 3.6F) and 50 % 6 5 % relativehumidity.Standard Conditions.6.2 Weight, rectangular, with dimensions of 41 by 19 mm (158 in. long by 34 in. wide) and mass of 30 g (1.06 oz).NOTE 3The thickness of the weight should be approximately 6 mm (14 in.) but planed to a thickness that
19、will provide the 30-g (1.06-oz) mass.6.3 Polyethylene Strips, several (often 6 or more), clear, low density with dimensions 127 by 25 by 0.15 mm (5 by 1 by 0.006in.).6.4 Timer, capable of measuring minutes and hours.6.5 Rectangular Plates, several (often 6 or more), rectangular, approximately 152 by
20、 76 mm (6 by 3 in.), made of non-porousmaterial such as tin plated steel or aluminum.6.6 Template, rectangular, of steel, brass or other suitable material, 3.2 mm (18 in.) thick with inside dimensions 95 by 25.4 mm(334 by 1 in.); outside dimensions approximately 120 by 31 mm (534 by 2 in.).7. Sampli
21、ng7.1 The test sample shall consist of a factory-sealed can of compound (minimum contents, 450 mL or 1 pt) with an appropriatecuring agent where applicable, or a standard cartridge, factory filled and sealed.8. Procedure (see Fig. 1)8.1 Thoroughly clean the templates and rectangular plates with meth
22、yl ethyl ketone, xylene, or similar solvent. (WarningMethyl ethyl ketone, xylene, and similar solvents are both toxic and flammable and should be handled with caution in a wellventilated hood.)8.2 Condition the sample of sealant in the original closed container for 24 h at 23 6 2C (73.4 6 3.6F) and
23、50 6 5 % relativehumidity. Standard Conditions. For single-component sealants, weigh out approximately 250 g of the sealant before testing. Formulti-component sealants, thoroughly mix 250 g of the base compound with the appropriate amount of curing agent following themanufacturers mixing instruction
24、s.8.3 Prepare at least two specimens for each sealant as follows: Center the template on the metal plate and carefully fill it withsealant avoiding air pockets. Strike off the surface flat using a metal straightedge, to a uniform thickness.FIG. 1 Stages in the Tack-Free Time Test ProcedureC679 1528.
25、4 Relative Tack-Free Time Unknown. If the relative tack-free time is unknown, the procedure is to pretest one of the testspecimens by lightly touching the surface of the sealant with a film of polyethylene wrapped over the end of a finger. Touch thetest piece in accordance with an appropriate time i
26、nterval described in 8.5. Try to touch a different place on the surface each time.After the polyethylene wrapped finger is lightly touched to the surface of the sealant, it is immediately removed and examined tosee if sealant was picked up on the polyethylene film. When no sealant is picked up on th
27、e polyethylene strip, perform the nexttest as described in 8.6.8.5 Time IntervalsIf the relative tack-free time is unknown, the procedure is to pretest, as in 8.4, one test specimen eachminute for the first 10 min, each 2 min for the next 10 min, each 5 min for the next 160 min (3 h has elapsed), ea
28、ch hour for thenext 69 h, each day until a positive result is achieved or until 21 days has elapsed. Table 1 summarizes the time intervals.NOTE 4Information provided by the manufacturer can save a great deal of time and lead the tester quickly to an appropriate time bracket.8.6 After the pretest in
29、8.4 do the actual test by starting new, but just before the tack-free time estimated by the pretest. At theappropriate time lay a polyethylene strip over half of the same test specimen and gently place the brass weight on the strip andallow it to remain there for 30 s.8.7 Remove the weight and then
30、slowly withdraw the polyethylene strip pulling it with thumb and forefinger at 90 to thecompound, at a constant rate of 1 in./15 s (see Fig. 1).8.8 If the strip is clean or almost clean, repeat the test of 8.6 and 8.7 on a previously undisturbed test specimen.8.9 If the strip is clean from the previ
31、ously undisturbed test specimen, record the time from the moment the template wasscraped level with a spatula until the pulling of this strip.8.10 If the polyethylene strip still has sealant adhering to it, wait half the time of the preceding test time interval and repeat thetest described in 8.6 an
32、d 8.7 on another undisturbed test piece.8.11 If the strip is again not clean, repeat 8.10 until a clean strip is achieved.8.12 If an approximate tack-free time is known, consult Table 1 and choose the total elapsed time interval that matches thesupposed tack-free time, back down one interval and sta
33、rt the pretest there and proceed with the pretest and test as described above.8.13 If the tack-free time is shorter than anticipated, start with fresh specimens and pick a shorter elapsed time as the startingpoint.8.14 If the tack-free time occurred at an occasion when no one was available to check
34、it (that is, night or weekend) start thetest over, at such a time where the anticipated final point will occur during working hours.NOTE 5Certain test conditions seem to have a particularly large influence on the accuracy of this test and therefore should be closely watched. Ofprime importance is pe
35、rforming the test at the called out temperature and humidity.conditions.9. Report9.1 Report the following information:9.1.1 Trade name or other identification of the sealant tested.9.1.2 Time of cure until no sealant was picked up on the polyethylene sheet from 8.9. The time should be reported to th
36、e nearestminute, nearest 2 min, or nearest 5 min, etc., as indicated by the time between tests. Record whether the film was clean or the filmcontained a thin layer of plasticizers.9.1.3 For Type M sealants describe the mixing systems, the time taken to mix, and the time from after mixing and the sta
37、rt ofthe tack-free time test.9.1.4 The temperature and relative humidity conditions utilized to generate the results, if different from standard conditions.10. Precision and Bias310.1 Round-robin testing done at (23 6 2C) 73.4 6 3.6F and 50 6 5 % relative humidity Standard Conditions on five typesof
38、 sealants by five laboratories indicates the precision between laboratories is 60 % of the test result (two standard deviations). Nodata is available to estimate precision within a laboratory. A summary of results is given in Table 2.3 Supporting data have been filed at ASTM International Headquarte
39、rs and may be obtained by requesting Research Report RR:C24-1024.TABLE 1 Summary of Time IntervalsFor First 10 MinTest Each MinuteFor Next 10 MinTest Each 2 MinFor Next 160 MinTest Each 5 MinFor Next 69 hTest Each HourFor Next 18 DaysTest Each DayTotal time elapsed 10 min 20 min 3 h 3 days 21 daysC6
40、79 15311. Keywords11.1 sealants; tack; tack-freeASTM 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,
41、 and the riskof infringement 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 revi
42、sion of this standard 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
43、shouldmake your views 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 o
44、btained 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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 0
45、1923, Tel: (978) 646-2600; http:/ 2 Precision SummaryTack-Free Time for ChemicalCuring Sealants (in hours)Material Average Value BetweenLaboratories Percent BetweenD 0.278 0.047 17.138C 0.306 0.076 25.059B 12.200 6.340 51.970A 16.300 2.636 16.173E 53.600 27.005 50.383Average 1 standard deviation 32.144C679 154
