ASTM D4338-97(2021)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4338 − 97 (Reapproved 2021)
Standard Test Method for
Flexibility Determination of Supported Adhesive Films by
Mandrel Bend
This standard is issued under the fixed designation D4338; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript 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. Scope E171 Practice for Conditioning and Testing Flexible Barrier
Packaging
1.1 This test method covers the determination of the flex-
ibility of an adhesive film bonded to a flexible substrate. The
3. Terminology
results are useful for comparing flexibility of adhesives and not
3.1 Definitions—For terms used in this standard, refer to
for absolute characterization of adhesives.
Terminology D907.
1.2 The values stated in SI units are to be regarded as the
3.2 Definitions of Terms Specific to This Standard:
standard. The values given in parentheses are provided for
3.2.1 mandrel, n—cylindrical rod.
information purposes only.
1.3 This standard does not purport to address all of the
4. Summary of Test Method
safety concerns, if any, associated with its use. It is the
4.1 Atest substrate coated with a film of adhesive, properly
responsibility of the user of this standard to establish appro-
sized and conditioned, is folded to form an inverted U-shaped
priate safety, health, and environmental practices and deter-
angle over the mandrel maintaining intimate contact with the
mine the applicability of regulatory limitations prior to use.
non-adhesive side. Using a fresh specimen for each test, the
1.4 This international standard was developed in accor-
test is repeated with progressively smaller diameter mandrels
dance with internationally recognized principles on standard-
until the adhesive fails (cracks) on bending. The flexibility
ization established in the Decision on Principles for the
value of the adhesive is the smallest diameter mandrel over
Development of International Standards, Guides and Recom-
which four out of five test specimens do not break.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
5. Significance and Use
5.1 Themandrelbendtestissimpleandfast.Itrequireslittle
2. Referenced Documents
investment in equipment and little operator training.The prime
2.1 ASTM Standards:
purpose is to determine whether a film of adhesive coated on a
D609 Practice for Preparation of Cold-Rolled Steel Panels
substrate meets flexibility requirements. The test is also useful
for Testing Paint, Varnish, Conversion Coatings, and
for comparing flexibility of adhesives. It can be used to design
Related Coating Products
adhesives by comparing the flexibility of various formulations
D907 Terminology of Adhesives
to meet specific end-use parameters. The adhesive flexibility
D3111 Practice for Flexibility Determination of Hot-Melt
can be determined at temperatures other than ambient by
Adhesives by Mandrel Bend Test
conditioning the test apparatus and test specimen at the desired
temperature and performing the test under those conditions.
This test method is under the jurisdiction of ASTM Committee D14 on
6. Apparatus
Adhesives and is the direct responsibility of Subcommittee D14.10 on Working
6.1 The test apparatus consists of a series of different
Properties.
Current edition approved April 1, 2021. Published April 2021. Originally
diameter cylindrical rods or mandrels supported at each end.
approved in 1984. Last previous edition approved in 2016 as D4338 – 97 (2016).
These should be long enough to permit placement of the flat
DOI: 10.1520/D4338-97R21.
side of a test specimen tangentially at right angles to the
This test method is intended to replace Method 1081 of Federal Test
longitudinal axis of the test mandrel. Individual requirements
Method 175A.Available from DLADocument Services, Building 4/D, 700 Robbins
Ave., Philadelphia, PA 19111-5094, http://quicksearch.dla.mil.
determine the diameter and lengths of the rods needed. For
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
1 1
most tests, rods 3.2 mm ( ⁄8 in.), 6.4 mm ( ⁄4 in.), and 12.8 mm
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
( ⁄2 in.) in diameter, by 75 to 150 mm (3 to 6 in.) in length,
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. made of brass or stainless steel, are satisfactory. Two simple
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D4338 − 97 (2021)
NOTE 1—Figures in parentheses are approximate.
FIG. 1 Test Mandrel (Various Diameters) for Test Frame
test frames are shown in Fig. 1, one with fixed mandrels, and the adhesive to be tested. An alternative to these steel test
the other designed to take any diameter mandrel. panels can be bonderized steel panels as available commer-
cially.
6.2 Test Support Panels, unless otherwise specified, are
6.2.2 Although steel is used in this test method, other
made of steel, not thinner than 0.25 mm (0.010 in.) nor thicker
flexible support substrates can be used, including other metals,
than 0.40 mm (0.016 in.).
plastics, and paper. Special surface preparation, for example,
6.2.1 The steel test panels are to be free of rust, corrosion,
and contamination. Prepare one face of each panel to a clean priming, corona discharge, and etching, can be defined for
surface according to Methods D609
...