8300 Datasheet, PDF (7/16 Pages) 3M Electronics – Static Dissipative Rigid Worksurface 8300 Series

C. “Gator Ply”: a commercially available backing material used as moisture barrier. Gator Ply does not
have the balancing qualities as a phenolic high pressure-backing sheet. For severe environmental
humidity swings, a phenolic backing sheet is recommended to balance the construction.
11.0 Adhesives
Many types of adhesive are available for use in applying laminate. Each type has certain characteristics
that make it more suitable for particular applications. Regardless which adhesive is selected, manufacturers'
recommendations should be followed carefully.
A. Contact adhesives:
This is the most common type of adhesive used with laminate. It works well on a variety of substrates
and does not require sophisticated equipment for fabrication. The only special equipment needed is a
nip roll capable of applying 50‑75 lbs. per inch (9‑16 kg/cm) of roll.
1. Pressure is very important for proper lamination regardless of the type of adhesive used, but it is
especially important when using contact adhesives. Solvent entrapment is also important, resulting in
a weak bond and latent delamination failures from the substrate.
2. Contact adhesive is available in both solvent and water‑basted systems. Water‑based adhesives are not
recommended for use on steel or iron substrates.
3. An important application for contact adhesives is postforming. The adhesive does not require long
cure under heat and pressure, and the heat inherent to the postforming operation itself assists in
establishing a firm adhesive bond between the laminate and the substrate.
4. It is recommended that a minimum of 80% of the surface area of both the laminate and the substrate
be covered with the contact adhesive. There is a tendency to apply insufficient adhesive. The result is
that the adhesive bond rill be stronger in some spots than in others, causing stresses in the laminate
that may lead to cracking. For this reason, “spot bonding” of the laminate to the substrate should
never be done. On the other hand, because most contact adhesives are neoprene‑based, too much
adhesive can also cause problems like delamination or movement of the adhesive itself.
5. The edges of the substrate surface should be double‑coated with adhesive prior to lamination.
Caution: When applying the second coat around the edges, make sure the first coat is dry
and the solvent had a chance to flash off.
6. Laminate will “move” slightly with varying humidity conditions. Contact adhesives permit this
movement to a greater extent than do thermosetting adhesives.
7. Typical of contact adhesives, it is not possible to lift and reposition the laminate once contact has
been established between the adhesive‑coated laminate and substrate.
8. The evaporation of solvent from the contact adhesive has a cooling effect that may cause moisture
to condense on the surface of the adhesive. This is referred to as “blushing” and can cause poor
bonding. “Force drying” the adhesive with hot air should reduce this problem.
NOTE: Flashing off of the solvent is dictated by the humidity in the work environment. High
humidity environments require additional time for this process.
B. Thermosetting adhesives:
These adhesives require time and/or heat for proper curing. A press is needed to apply pressure while
the adhesive cures; 20 psi (1.41 kg/sq cm) is typical. Most thermosetting adhesives are two‑part systems
with a specified “pot life,” i.e., they must be used within a limited amount of time once the two parts are
mixed together.
1. Resorcinol: This is the best adhesive for use in applications where cracking due to humidity variations
may be a problem. Resorcinol is recommended where good resistance to water and heat is required.
2. Epoxy: This adhesive is good for applications calling for gap‑filling and low shrinkage. It is primarily
used to bond laminate to metal substrates. Because epoxy adhesives are generally “100% solids”
(solvent‑free), there is no solvent to flash off and problems related to solvent being trapped in the
substrate do not exist. Like Resorcinol, epoxies are good adhesives for applications in which cracking
due to humidity variations could be a problem.
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