1、Designation: D4338 97 (Reapproved 2011)1Standard 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 r
2、evision, 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 Department of Defense.1NOTEUnits of measure were e
3、ditorially changed from hard to soft conversions in Section 7 and a typo was corrected inFootnote 3 in April 2011.1. Scope1.1 This test method covers the determination of the flex-ibility of an adhesive film bonded to a flexible substrate. Theresults are useful for comparing flexibility of adhesives
4、 and notfor absolute characterization of adhesives.1.2 The values stated in SI units are to be regarded as thestandard. The values given in 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.
5、It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D609 Practice for Preparation of Cold-Rolled Steel Panelsfor Testing Paint, Va
6、rnish, Conversion Coatings, andRelated Coating ProductsD907 Terminology of AdhesivesD3111 Test Method for Flexibility Determination of Hot-Melt Adhesives by Mandrel Bend Test MethodE171 Specification for Atmospheres for Conditioning andTesting Flexible Barrier Materials3. Terminology3.1 DefinitionsF
7、or 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 Method4.1 A test substrate coated with a film of adhesive, properlysized and conditioned, is folded to form an inverted U-shapedangle over th
8、e mandrel maintaining intimate contact with thenon-adhesive side. Using a fresh specimen for each test, thetest is repeated with progressively smaller diameter mandrelsuntil the adhesive fails (cracks) on bending. The flexibilityvalue of the adhesive is the smallest diameter mandrel overwhich four o
9、ut 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 little operator training. The primepurpose is to determine whether a film of adhesive coated on asubstrate meets flexibility requirements. The tes
10、t is also usefulfor comparing flexibility of adhesives. It can be used to designadhesives by comparing the flexibility of various formulationsto meet specific end-use parameters. The adhesive flexibilitycan be determined at temperatures other than ambient byconditioning the test apparatus and test s
11、pecimen at the desiredtemperature and performing the test under those conditions.6. Apparatus6.1 The test apparatus consists of a series of differentdiameter cylindrical rods or mandrels supported at each end.These should be long enough to permit placement of the flatside of a test specimen tangenti
12、ally at right angles to thelongitudinal axis of the test mandrel. Individual requirementsdetermine the diameter and lengths of the rods needed. Formost tests, 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,1This test method is under the
13、 jurisdiction of ASTM Committee D14 onAdhesives and is the direct responsibility of Subcommittee D14.10 on WorkingProperties.Current edition approved April 1, 2011. Published April 2011. Originallyapproved in 1984. Last previous edition approved in 2004 as D4338 97 (2004).DOI: 10.1520/D4338-97R11E01
14、This test method is intended to replace Method 1081 of Federal TestMethod 175A. Available from Standardization Documents Order Desk, DODSSP,Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dodssp.daps.dla.mil.2For referenced ASTM standards, visit the ASTM website, www.astm.or
15、g, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.made of brass
16、 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.36.2 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
17、.).6.2.1 The steel test panels are to be free of rust, corrosion,and contamination. Prepare one face of each panel 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 co
18、mmer-cially.6.2.2 Although steel is used in this test method, otherflexible support substrates can be used, including other metals,plastics, and paper. Special surface preparation, for example,3Available from Paul N. Gardner Company, Inc., 313 NE 1st St. PompanoBeach, FL 33060.NOTE 1Figures in paren
19、theses are approximate.FIG. 1 Test Mandrel (Various Diameters) for Test FrameD4338 97 (2011)12priming, 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
20、as a doctorblade.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:7.3.1 A doctor blade is normally used to cast a uniformadhesive film at least 50 mm (2 in.) wide 100 mm (4 in.) longa
21、nd 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 acceptable coating procedures such as dip, flow, andspray can be used as long as a uniform coating results
22、 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 theadhesive film visible to the naked eye are permitted. Measurethe thickness dimension to within 0.01 mm (0.0004
23、 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 low tempera-tures, a minimum of 4 h conditioning can be used. Note thischange when recording data. If other condition
24、s 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 environment used to conditionthe test specimens and test apparatus.9.2 Put the largest diameter mandrel i
25、n 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 testing, use cotton work gloves toinsulate the test specimens from the warm fingers.9.4 Lay the flat stee
26、l (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 the mandrel to form an inverted U-shaped angleover the mandrel maintaining intimate contact with the ma
27、n-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 changes or blushing, not affecting the tensile propertiesof the materials, are not considered as fail
28、ure, 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 test five times, using five fresh specimens, onthe smallest-diameter mandrel at which failure had not oc
29、-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 value of the adhesive as thesmallest-diameter mandrel over which four out of five testspecimens passed.10
30、. 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 specimen preparation, dipped, drawndown, flowed, sprayed, or other method.10.1.3 Test specimen dimension,
31、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,relative humidity.10.1.6 Conditioning and test conditions: temperature andrelative humidity.10.1.7 Smalle
32、st-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 change or blushing if visible of nonfailing testspecimens after bending.11. Precision and Bias11.1 Th
33、is is a comparative, working test. No precision orbias study is needed.12. Keywords12.1 flexibility; mandrel bend; supported adhesiveD4338 97 (2011)13ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. User
34、s of this standard are expressly advised that determination of the validity of any such patent rights, 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
35、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 comments will receive careful consideration at a meeting of theresponsible technica
36、l 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 copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
37、 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 ASTM website (www.astm.org/COPYRIGHT/).D4338 97 (2011)14
