Structural Adhesive Film

AF 31

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9.

Environmental Aging of 3M™ Scotch-Weld™ Structural Adhesive Film AF 31 on Steel

The following data shows typical values obtained with Scotch-Weld AF 31 film adhesive in steel overlap

bonds. All properties were measured on 1" wide, 1/2" overlap specimens cut from .035" thick 4" x 8"

bonded panels of 1020 cold rolled steel. The 1020 steel was cleaned with toluene solvent. Tests were

conducted according to MMM-A-132 methods.

A. Original Properties

Product Performance

(continued)

Note: The following technical information and data should be considered representative

or typical only and should not be used for specification purposes.

Overlap Shear Strength (psi)

-40°F

75°F

250°F

350°F

450°F

(-40°C)

(24°C)

(121°C)

(177°C)

(232°C)

Cure Cycle A

350°F (177°C), 60 min., 150 psi, 200°F (93°C)

2600

2195

1800

1720

660

per minute rise rate to cure temperature.

Cure Cycle B

450°F (232°C) press temp., 350 psi,

250

2510

1520

1400

480

15 seconds in the press, maximum bond line

temperature attained 412°F (212°C).

B. Environmental Aging Properties (Specimens cut to 1" width prior to immersion)

75°F (24°C) Overlap Shear (psi)

Environment

Cure Cycle A

Cure Cycle B

Control

2195

2510

100% RH @ 100°F (38°C) for 7 days

1910

2530

120°F (49°C) Tap Water for 7 days

1650

1530

75°F (24°C) Gasoline for 7 days

2090

2530

75°F (24°C) Methanol for 7 days

2020

2410

95°F (35°C) Salt Spray for 7 days

1760

2810

10. Effect of Overlap Length on Scotch-Weld AF 31 Film Adhesive Shear Strength

The effect of overlap length on shear strength of Scotch-Weld AF 31 film adhesive was determined on 1"

wide specimens of varying length overlap, cut from .063" thick bonded panels of 2024 T3 clad aluminum.

The cure cycle used was 350°F (177°C), 60 minutes, 150 psi, 200°F (93°C)/min. rise rate.

Length of

Actual

Overlap

Load (lbs.)

psi

1/4"

1425

5700

3/8"

1740

4640

1/2"

2000

4000

3/4"

2500

3340

1"

2900

2400

3230

2150

2"

3270

1634

3"

3600

1200