MMM-A-1617B
"after accelerated" storage tests shall be prepared with fresh adhesive. For
the "after accelerated" storage tests, adhesive conditioned as specified in
4.6.5 shall be used. A rectangle of vinyl plastic, polychloroprene or duck as
applicable, measuring 17.8 cm by 31.8 cm (7 inch by 12.5 inch) shall be
covered on one surface at one time with adhesive to form a coated area 11.3 cm
by 17.8 cm (4.5 inch by 7 inch) running the full width of the material. The
top edge of strips of aluminum measuring 2.5 by 15.2 by .161 cm (1 by 6 by
0.064 inch) shall be placed in firm contact with the top edge of the adhesive-
coated material in such a manner that a bonded area on each strip of 2.5 by
11.3 cm (1 by 4.5 inch) shall be produced. Approximately .64 cm (.25 inch)
separation between strips shall be maintained (see figure 1). Strips of tape
may be used to secure the aluminum panels during preparation of the test
specimens. Cleaning, drying time between coats, number of coats on each
material and conditioning shall be accomplished in accordance with 4.5.1 and
4.5.2. After conditioning, the sheet shall be cut to separate the strips,
leaving a loose, unbonded tail approximately 20 cm (8 inches) in length on
each specimen. This procedure prepares 5 specimens for test.
4.6.2.2 Apparatus. Strip adhesion strength tests shall be performed on
an autographic power-driven inclination pendulum, or strainage type testing
machine. If an inclination or pendulum type is used, it shall be of such
capacity that the tension during test shall not exceed 85 percent nor be less
than 15 percent of the rated capacity.
4.6.2.3
Procedure.
4.6.2.3.1 As received. Specimens shall be prepared in accordance with
4.6.2 and conditioned in accordance with 4.5.1. Tests shall be conducted
within 24 hours after completion of the conditioning period. The specimens
shall be mounted in the machine specified in 4.6.2.2 and the adhered material
peeled from the aluminum strip at an angle of 180° at the rate of 5 cm/min (2
inches per minute) at standard conditions. Strength values for the first and
last inch of the specimen shall not be used. The strip adhesion strength for
each specimen shall be the numerical average of the loads. Five specimens
shall be tested for each determination. Strip adhesion strength shall be
reported as the numerical average of the five specimens tested and shall pass
the requirements specified in table I.
4.6.2.3.2 After immersion. Specimens shall be prepared in accordance
with 4.6.2 and conditioned as specified in 4.5.1. Within 24 hours after
completion of the conditioning period, the specimens shall be immersed for 22
hours in distilled water, petroleum oil (oil No. 1 of ASTM D471) or aromatic
fuel (Reference Fuel B of ASTM D471) as applicable. Water and fuel immersions
shall be at standard conditions. Oil immersions shall be at 71°± 1°C
(160°± 2°F); specimens shall be cooled in a fresh sample of oil at standard
conditions for approximately 30 minutes. All specimens shall be tested in
accordance with 4.6.2.3.1 within 5 minutes after removal from the fluid and
shall pass the requirements specified in table I.
4.6.2.3.3 After bond aging. Specimens shall be prepared in accordance
with 4.6.2 and conditioned as specified in 4.5.1. Within 24 hours after
completion of the conditioning period, the specimens shall be placed in a
circulating air oven at 70°± 1°C (158°± 2°F) for a period of 7 days, then
removed, and held at standard conditions for 24 hours prior to testing in
accordance with 4.6.2.3.1.
4.6.2.3.4 After accelerated storage. Adhesive aged in accordance with
4.6.5 shall be used to prepare specimens as specified in 4.6.2 followed by
conditioning in accordance with 4.5.1. Tests shall be conducted as specified
in 4.6.2.3.1 within 24 hours after completion of the conditioning period.
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