ASTM F1536-95(1999)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:F1536–95(Reapproved 1999)
Standard Test Method for
Determining Strength and Setting Time of Synthetic Water-
Activated Polyurethane Fiberglass Orthopaedic Casting
Tape
This standard is issued under the fixed designation F 1536; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.2 maximum deflection load—the test cylinder is com-
pressed 0.4 in. (10 mm) from the initial load position without
1.1 This test method covers the functional diametral com-
noticeable failure or a measurable decrease in load.The load at
pression strength of cylindrical test specimens formed from
0.4 in. (10 mm) deflection shall be called the maximum
synthetic fiberglass polyurethane casting materials. The test
deflection load.
specimens employed in this test are similar in geometry and
3.1.3 peak failure load—failure of the test cylinder with a
construction to casts used in orthopaedic applications.This test
concomitantdecreaseinloadpriorto0.4in.(10mm)diametral
method is not intended to determine the strength of the base
compression. The highest load attained prior to the decrease
materials used for fabrication of the test specimen.
shall be called the peak failure load.
1.2 The values stated in inch-pound units are to be regarded
as the standard. The SI units given in parentheses are for
4. Summary of Test Method
information only.
4.1 Atestcylinderispreparedbyimmersingthecastingtape
1.3 This standard does not purport to address all of the
in 75 6 2°F (23.9 6 1.1°C) water, squeezing per the
safety concerns, if any, associated with its use. It is the
manufacturer’s instructions under the surface of the water, and
responsibility of the user of this standard to establish appro-
thenwrappingaroundeithera2.0in.(50.8mm)or2.5in.(63.5
priate safety and health practices and determine the applica-
mm)outsidediametercylindricalmandrel.Thetapeiswrapped
bility of regulatory limitations prior to use. Specific precau-
layer upon layer producing a five layer cylinder. The test
tionary statements are given in Note 1.
cylinder is removed from the mandrel after an initial setting
2. Referenced Documents period. After a specified time, the test specimen is positioned
on its side between two flat platens in the testing machine and
2.1 ASTM Standards:
compressedtodetermineitsstrength.Ambienttemperatureand
E 4 Practices for Force Verification of Testing Machines
humidity are specified because of their pronounced effect on
E 691 PracticeforConductinganInterlaboratoryTestStudy
material properties during the curing period.
to Determine the Precision of a Test Method
5. Significance and Use
3. Terminology
5.1 Diametralcompressionstrengthisanimportantmeasure
3.1 Definitions of Terms Specific to This Standard:
of the mechanical properties of casting materials. This test
3.1.1 diametral compression strength—the load per unit
method simulates the loading pattern seen in lower extremity
width in lbs/in. (Newtons/mm), calculated by dividing either
casting applications during ambulation. This method cannot be
the peak failure load or the maximum deflection load by the
used to determine cast life or measure bending or other modes
nominal sample length (that is, manufacturer’s stated tape
of cast failure.
width).
5.2 Thistestmethodmeasuresbutdoesnotprescribevalues.
6. Apparatus
This test method is under the jurisdiction ofASTM Committee F-4 on Medical
and Surgical Materials and Devicesand is the direct responsibility of Subcommittee
6.1 Testing Machines— Machines used for compression
F04.15 on Material Test Methods.
testing shall conform to the requirements of Practices E 4. For
Current edition approved May 15, 1995. Published July 1995.
universal machines with a common test space, calibration shall
Annual Book of ASTM Standards, Vol 03.01.
Annual Book of ASTM Standards, Vol 14.02. be performed in compression.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F1536
6.1.1 The surfaces of the flat platens shall be perpendicular 6.4 Water Container— A container capable of holding at
to the loading axis and parallel at all times within 0.005 in./in. least 1 gal (3.78 L) of water and of sufficient depth to allow
(1.3 mm/mm). Platen surfaces should be clean and free of complete immersion of the casting tape.
corrosion. 6.5 Release Liner— A sheet form liner of nominal thick-
6.1.2 The testing machine shall be capable of producing a
ness, such as waxed paper, shall be used to cover the mandrel
constant compression rate between 1 to 10 in./min (25.4 to 254 and prevent adhesion of the resin to the mandrel. This liner
mm/min).
must allow release of the cured specimen from the mandrel
6.1.3 The testing machine shall be capable of measuring the with minimal force, and must be easily removable from the
compressive load within 60.5 lbs (2.2 N).
specimen inner diameter prior to compression testing.
6.2 Test Specimen Preparation Mandrel—A solid, cylindri-
6.6 Timer—A timing device accurate to 61s.
cal aluminum mandrel of sufficient length to accommodate
6.7 Gloves—Gloves capable of protecting the hands from
three test specimens without end contact shall be mounted in a
contact with the resin, for example, latex surgical gloves.
horizontal position (see Fig. 1). Either of two mandrel diam-
NOTE 1—Precaution: Contact with uncured or curing resins should be
eters may be used: Type I—2.00 in. (50.8 mm) diameter, or
avoided. These resins may adhere to the skin and be difficult to remove.
Type II—2.50 in. (63.5 mm) diameter.
In addition, most polyurethane resins contain isocyanate to which some
6.2.1 Option—Three individual mandrels, either Type I or
individuals are or may become sensitized. Gloves should be worn at all
Type II, each capable of holding one test specimen, may be
times when handling uncured or curing casting tape.
substituted for a single, solid mandrel.
6.8 Thermometer— A device capable of measuring tem-
6.3 Constant Tension Method—Each layer of tape shall be
peratures within 6 1°F (0.5°C) in the 70 to 80°F (21.1 to
wrapped on the mandrel at a constant tension of 0.25 lbs/in.
26.7°C) range.
(4.5 g/mm) width of tape. Suggested methods for accomplish-
ing this include the use of a dead weight clamped to the free
7. Reagents and Materials
end of the tape while the horizontally mounted mandrel is
manually rotated (see Fig. 1), or the use of an automated 7.1 Atleastthreerollsofthecastingtapeshallbetested;one
constant torque winding mechanism (see Fig. 2). roll for each of the three specified time periods. Three test
FIG. 1 Manual Preparation Method
F1536
FIG. 2 Automated Constant Torque Preparation Method
cylinders shall be prepared from each roll without the use of 9.9 Molding—Primary test samples should be prepared
manual molding techniques. without the use of manual molding. If testing of samples with
the use of manual molding is desired, a secondary group of
NOTE 2—If testing of cylinders with the use of manual molding is
samples should be prepared using the desired molding tech-
desired, a secondary group of samples should be prepared using the
nique. Record the molding time and degree of manipulation
desired molding technique.
used.
7.2 Water for initiation of the curing process shall be
9.10 Setting Time— This is determined by a manual inden-
maintained at 75 6 2°F (23.9 6 1.1°C).
tation test, that is, the time elapsed from the initial immersion
7.2.1 The water shall be changed after three rolls have been
until the test cylinder cannot be indented by moderate finger-
prepared.
nail pressure. Begin indentation testing for material setting
8. Sample Conditioning
after all 3 samples from a single roll are wrapped. Repeat the
test every 15 s until all samples are set. Record the three times
8.1 Store each package flat, with each roll on its side, at 70
and report the average as the setting time.
6 5°F (21.1 6 2.8°C) for at least 24 h before use.
8.2 Open each package immediately prior to use.
9.11 After the test cylinders have set, remove them from the
mandrel taking care to avoid deforming them. Remove the
9. Specimen Preparation
release liner from the inside of the test cylinders.
9.1 Beforeopeningeachpackage,recordthemanufacturer’s
9.12 Stand test specimens on end with enough space be-
name, product description, size (width and length), and lot
tween samples to allow air to freely circulate between the
number.
cylinders.
9.2 Wrap the release liner around test specimen preparation
mandrel and secure with tape.
10. Procedure
9.3 Open the package and loosely grasp roll with core
10.1 Testing Speed— The recommended constant crosshead
p
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