1、Designation: D4338 97 (Reapproved 2016)Standard Test Method forFlexibility Determination of Supported Adhesive Films byMandrel Bend1This standard is issued under the fixed designation D4338; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, the year 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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This test me
3、thod covers the determination of the flex-ibility of an adhesive film bonded to a flexible substrate. Theresults are useful for comparing flexibility of adhesives and notfor absolute characterization of adhesives.1.2 The values stated in SI units are to be regarded as thestandard. The values given i
4、n parentheses are provided forinformation purposes only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bilit
5、y of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D609 Practice for Preparation of Cold-Rolled Steel Panelsfor Testing Paint, Varnish, Conversion Coatings, andRelated Coating ProductsD907 Terminology of AdhesivesD3111 Test Method for Flexibility Determination of Hot
6、-Melt Adhesives by Mandrel Bend Test MethodE171 Practice for Conditioning and Testing Flexible BarrierPackaging3. Terminology3.1 DefinitionsFor terms used in this standard, refer toTerminology D907.3.2 Definitions of Terms Specific to This Standard:3.2.1 mandrel, ncylindrical rod.4. Summary of Test
7、Method4.1 A test substrate coated with a film of adhesive, properlysized and conditioned, is folded to form an inverted U-shapedangle over the mandrel maintaining intimate contact with thenon-adhesive side. Using a fresh specimen for each test, thetest is repeated with progressively smaller diameter
8、 mandrelsuntil the adhesive fails (cracks) on bending. The flexibilityvalue of the adhesive is the smallest diameter mandrel overwhich four out of five test specimens do not break.5. Significance and Use5.1 The mandrel bend test is simple and fast. It requires littleinvestment in equipment and littl
9、e operator training. The primepurpose is to determine whether a film of adhesive coated on asubstrate meets flexibility requirements. The test is also usefulfor comparing flexibility of adhesives. It can be used to designadhesives by comparing the flexibility of various formulationsto meet specific
10、end-use parameters. The adhesive flexibilitycan be determined at temperatures other than ambient byconditioning the test apparatus and test specimen at the desiredtemperature and performing the test under those conditions.6. Apparatus6.1 The test apparatus consists of a series of differentdiameter c
11、ylindrical rods or mandrels supported at each end.These should be long enough to permit placement of the flatside of a test specimen tangentially at right angles to thelongitudinal axis of the test mandrel. Individual requirementsdetermine the diameter and lengths of the rods needed. Formost tests,
12、rods 3.2 mm (18 in.), 6.4 mm (14 in.), and 12.8 mm(12 in.) in diameter, by 75 to 150 mm (3 to 6 in.) in length,made of brass or stainless steel, are satisfactory. Two simpletest frames are shown in Fig. 1, one with fixed mandrels, andthe other designed to take any diameter mandrel.31This test method
13、 is under the jurisdiction of ASTM Committee D14 onAdhesives and is the direct responsibility of Subcommittee D14.10 on WorkingProperties.Current edition approved May 1, 2016. Published May 2016. Originallyapproved in 1984. Last previous edition approved in 2011 as D4338 97 (2011)1.DOI: 10.1520/D433
14、8-97R16.This test method is intended to replace Method 1081 of Federal TestMethod 175A.Available from DLADocument Services, Building 4/D, 700 RobbinsAve., Philadelphia, PA 19111-5094, http:/quicksearch.dla.mil.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custo
15、mer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Paul N. Gardner Company, Inc., 313 NE 1st St. PompanoBeach, FL 33060.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700,
16、West Conshohocken, PA 19428-2959. United States16.2 Test Support Panels, unless otherwise specified, aremade of steel, not thinner than 0.25 mm (0.010 in.) nor thickerthan 0.40 mm (0.016 in.).6.2.1 The steel test panels are to be free of rust, corrosion,and contamination. Prepare one face of each pa
17、nel to a cleansurface according to Methods D609 to allow better adhesion ofthe adhesive to be tested. An alternative to these steel testpanels can be bonderized steel panels as available commer-cially.6.2.2 Although steel is used in this test method, otherflexible support substrates can be used, inc
18、luding other metals,plastics, and paper. Special surface preparation, for example,priming, corona discharge, and etching, can be defined forthese substrates before coating the adhesive.6.3 Device, capable of producing adhesive coatings ofuniform thickness within (61-mL) tolerances, such as a doctorb
19、lade.7. Sampling, Test Specimens, and Test Units7.1 The test sample will be representative of the adhesivetested.7.2 Measure substrate,7.3 Prepare test coating as follows:NOTE 1Figures in parentheses are approximate.FIG. 1 Test Mandrel (Various Diameters) for Test FrameD4338 97 (2016)27.3.1 A doctor
20、 blade is normally used to cast a uniformadhesive film at least 50 mm (2 in.) wide 100 mm (4 in.) longand of the thickness desired to the clean side of the steel testsupport panel or to any other designated test support substrate.If a suitable doctor blade is not used or available, othermutually acc
21、eptable coating procedures such as dip, flow, andspray can be used as long as a uniform coating results meetingthe required thickness. Allow adhesive to set as described inthe materials specifications or if not given, as recommended bythe manufacturer of the adhesive. No flaws anywhere in theadhesiv
22、e film visible to the naked eye are permitted. Measurethe thickness dimension to within 0.01 mm (0.0004 in.).8. Conditioning8.1 Store the test specimens and test apparatus at the testconditions for 24 h. Perform the test under these sameconditions. For rapid screening, particularly at lowtemperature
23、s, a minimum of 4 h conditioning can be used. Notethis change when recording data. If other conditions are notspecified, the storage and test conditions are 23 6 2C and 506 5 % relative humidity. Specification E171 details these andother test conditions.9. Procedure9.1 Run the tests in the same envi
24、ronment used to conditionthe test specimens and test apparatus.9.2 Put the largest diameter mandrel in the horizontaloperating position in the test frame.9.3 Grasp the test specimen between the thumb and forefin-ger of one hand, with the longest dimension between thefingers. For low-temperature test
25、ing, use cotton work gloves toinsulate the test specimens from the warm fingers.9.4 Lay the flat steel (or other support substrate) of the testspecimen tangentially at right angles to the longitudinal axis ofthe test mandrel.9.5 Within 1 s, fold the test specimen with the adhesive sideopposite to th
26、e mandrel to form an inverted U-shaped angleover the mandrel maintaining intimate contact with the man-drel.9.6 Failure is a fracture, crazing, or cracking of the adhesivefilm visible to the naked eye. This can occur at any time duringthe bending of the adhesive test specimen over the mandrel.Color
27、changes or blushing, not affecting the tensile propertiesof the materials, are not considered as failure, but should bereported.9.7 If no failure occurs, fold a fresh specimen over the nextsmaller diameter mandrel. Repeat the test using a fresh sampleeach time until failure occurs.9.8 Repeat the tes
28、t five times, using five fresh specimens, onthe smallest-diameter mandrel at which failure had not oc-curred; at least four out of five test specimens must pass.Follow this procedure with smaller- or larger-diameter man-drels until four out of five test specimens pass.9.9 Record the flexibility valu
29、e of the adhesive as thesmallest-diameter mandrel over which four out of five testspecimens passed.10. Report10.1 The report should include the following:10.1.1 Complete identification of the material tested, includ-ing types, source, manufacturers code number, forms, etc.10.1.2 Method of test speci
30、men preparation, dipped, drawndown, flowed, sprayed, or other method.10.1.3 Test specimen dimension, especially adhesive coat-ing thickness to within 0.0025 mm (0.01 in.) substrate thick-ness.10.1.4 Number of coats of adhesive applied.10.1.5 Set time for each coat, temperature, and if important,rela
31、tive humidity.10.1.6 Conditioning and test conditions: temperature andrelative humidity.10.1.7 Smallest-diameter mandrel over which four out offive test specimens did not fail.10.1.8 Observation for cracks, flakes, or chips in adhesiveupon bending of test panel for each individual test.10.1.9 Color
32、change or blushing if visible of nonfailing testspecimens after bending.11. Precision and Bias11.1 This is a comparative, working test. No precision orbias study is needed.12. Keywords12.1 flexibility; mandrel bend; supported adhesiveASTM International takes no position respecting the validity of an
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34、ision 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 should be addressed to ASTM International Headquarters. Your
35、 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 Standards, at the address shown below.This standard is copyr
36、ighted 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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 97 (2016)3
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