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Design and Tape Selection Considerations

Choose the right tape for the substrate: Adhesives must flow onto the substrate surfaces in order to achieve intimate contact

area and allow the molecular force of attraction to develop. The degree of flow of the adhesive on the substrate is largely

determined by the surface energy of the substrate.

Adhesive

High surface energy

— Substrate

Adhesive

Low surface energy

— Substrate

This illustration demonstrates the effect of surface energy on adhesive interfacial contact. High surface energy materials

draw the adhesive closer for high bond strength.

Relationship of Adhesion and Surface Energy for 3M™ VHB™ Tape Adhesive Families

1100-400

50-42

39-38

37-36

33-18

(High)

(Medium)

(Low)

Surface Energy (Dynes/cm)

Aluminum

Stainless Steel

Copper

Zinc

Tin

Lead

Anodized Aluminum

Glass

Polyimide

Phenolic

Nylon

Alkyd Enamel

Polyester

Epoxy Paint

Polyurethane

ABS

Polycarbonate

PVC

PPE

Acrylic

PU Enamel

Powder Paint

PVA

Polystyrene

Acetal

PVDF Paint

Powder Paint

Polypropylene

EVA

Polyethylene

PVF

Silicone

PTFE

NOTES: There are a wide variety of formulations, surfaces finishes and surface treatments available on substrate materials which can affect adhesion. This chart is intended

to provide only a rough estimate of the adhesion levels which can be expected on some common materials relative to a reference surface such as aluminum.

Foam type can affect and/or limit maximum adhesive strength.

Use the right tape thickness: The necessary thickness of tape depends on the rigidity of substrates and their flatness irregularity.While

the

3M™VHB™Tapeswillconformtoacertainamountofirregularity,theywillnotflowtofillgapsbetween the materials.For bonding rigid

materials with normal flatness, consider use of tapes with thickness of 45 mils (1.1 mm) or greater. As the substrate flexibility

increases thinner tapes can be considered.

Use the right amount of tape: Because

3M™ VHB™ Tapes are viscoelastic by nature their strength and stiffness is a function oftherate at

which they are stressed.They behave stronger with relatively faster rate of stress load (dynamic stresses) and willtendtoshowcreep

behaviorwithstressloadactingoveralongperiodoftime(staticstresses).Asageneralrule,forstatic loads, approximately four square

dynamic loads, the dynamic performance characteristics provided on page 4 should be useful, factoring in the appropriate safety factors.

Allow for thermal expansion/contraction:

3M™ VHB™ Tapes can perform well in applications where two bonded surfaces may expand

and contract differentially. Assuming good adhesion to the substrates, the tapes can typically tolerate differential movement in the shear

plane up to 3 times their thickness.

Bond Flexibility: While an advantage for many applications where allowing differential movement is a benefit, the tape bonds are typically

more flexible than alternative bonding methods. Suitable design modifications or periodic use of rigid fasteners or adhesives may be

needed if additional stiffness is required.

Severe Cold Temperature: Applications which require performance at severe cold temperatures must be thoroughly evaluated bytheuserif

theintendedusewillsubjectthetapeproducttohighimpactstresses.Atechnicalbulletin

“3M™VHB™TapeCold Temperature

Performance” (70-0707-3991-0) is available for additional information.

GPH Family

LSE Family