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Structural Adhesive Film

AF 32

Product Application (continued)

Cure Temperature

The cure temperature may be varied from 250°F to 450°F (121°C to 232°C), depending on the materials being

bonded, equipment available and bond properties desired. The desired pressure must be applied before the glue line

reaches 160°F (71°C). The film will soften as temperature is increased to 180°F-210°F (82°C-99°C) and will wet

the surface to which it has been applied. A chemical cure will be initiated between 200°F and 270°F (93°C and

132°C) and a low strength gel formed. Continued heating chemically converts this gel into a high strength, solvent

resistant bond. Scotch-Weld AF 32 will change color only slightly upon application of heat. Edges of the bond which

are exposed to air will change from yellow to rusty brown.

Cure Time

Cure time depends on the cure temperature used, methods of heat application, production limitations and bond

properties required. Since no two bonding operations are exactly alike it is suggested that a few simple experiments

be conducted, varying both temperature and cure time to determine optimum conditions for the particular application.

Figure II is a guide from which an approximate cure cycle can be taken for various cure times or temperatures.

Figure II

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

250°F (121°C)

300°F (149°C)

350°F (177°C)

400°F (204°C)

450°F (232°C)

500°F (260°C)

Cure Time (Minutes)

A. Optimum bond properties. (Creep

resistance, high temperature strength,

environmental resistance, etc.)

B. General purpose bond properties.

(Shear strength over 2,500 psi (17.2 MPa)

at 75°F ± 2°F (24°C ± 1.1°C.)

C. Cure initiation temperature.

A

B

C

Suggested Cure Cycle

The following press cure cycle is suggested to obtain dense glue lines and was used to obtain the strengths reported

in the Test Data section unless otherwise stated.

1. Apply a pressure of 100 psi (.7 MPa) prior to reaching a bond line temperature of 150°F (66°C) and maintain

throughout the press cure cycle.

2. Raise the bond line temperature from ambient to 350°F (177°C) at a rate of 10°F-12°F (5.6°C-6.7°C) per minute.

3. Cure for 120 minutes at 350°F (177°C).

4. Cool to below 200°F (93°C) bond line temperature prior to release of pressure. (In laboratory tests, panels have

been removed at 350°F (177°C) with no adverse effects.