What adhesive types are best for bonding composites?

Cyanoacrylates, Epoxy Adhesives, Polyurethane Adhesives, Structural Acrylic Adhesives, and UV Cure Adhesives all bond well to composites.  So which adhesive type is the best?  It depends upon the type of composite and the desired assembly process, and the requirements of the bond.  The following reviews a few of the various adhesive types.

EPOXY ADHESIVES

Epoxy adhesives are likely the most common adhesives for composites.  Heat curable single component epoxies provide high-strength bonds to many composite materials.  Clamping or jigging of components is needed to ensure the piece stays properly aligned while moved into the oven and throughout the heat cure cycle.  After cooling, the clamps are removed, and the assembly can then be painted and put back in the paint bake oven.

Two component room temperature epoxy adhesives often provide more versatility in the composite bonding manufacturing process and are also quite high strength.

There are also two component epoxy adhesives that cure at room temperature and also with heat for increased adhesion properties.

Modified epoxy adhesives are formulated to provide flexibility and provide shock-absorbing properties between the composite pieces that have been bonded.

STRUCTURAL ACRYLIC

Both surface activated structural acrylic adhesives, and 1:1 mix structural acrylic adhesives are used in composite bonding as they provide very high strength bonds to composite with high peel strength.

Surface activated acrylic adhesives are very fast setting.  Permabond TA4246 is toughened and achieves handling strength in under 4 minutes.

1:1 mix ratio methyl methacrylates provide gap-filling properties.  Permabond TA4810, a 1:1 mix structural acrylic is gap filling making it ideal for bonding of rough surfaces.

POLYURETHANE ADHESIVES

Two-component polyurethanes are ideal for bonding large composite assemblies – such as bonding the 2 skins of a car hood together.

CYANOACRYLATES

Cyanoacrylate adhesives, also known as instant adhesives, are ideal for creating strong bonds very quickly in applications that don’t require high impact or peel resistance. Cyanoacrylate adhesives are also used in place of clamps or jigs to hold the assembly in place while a longer curing two component adhesive bonds.

UV CURABLE ADHESIVES

UV curable adhesives are used to bond composite to clear glass or plastic and are also used to coat composites.

Contact the technical team at Permabond to review your application for a product recommendation.