Bond Composites with Flexible Epoxy
Two-part epoxies are normally regarded as rigid materials and generally have excellent compressive, tensile and shear strength but limited performance in terms of peel strength and flexibility. Rubber toughened epoxies tend to fare a little bit better, offering the user better impact and vibration resistance, combined with the ability to absorb stress caused by differential expansion and contraction of dissimilar substrate materials.
Permabond has developed new modified epoxy technology which combines typical epoxy curing characteristics with the flexibility of an RTV-type silicone – and the strength performance is not too shabby either!
These products have been developed to bond a wide variety of plastics, metals and in particular composite materials. Carbon fibre (or Carbon fiber depending on which side of the “pond” you’re from!) is the 21st century whizzy substrate of choice for all things high performance e.g. sports equipment, prosthetics, race cars, performance bikes etc. Given the material is expected to absorb impact, vibration and all sorts of stress and strain without shattering, it is important to reflect these desired properties in the adhesive. These flexible products can also be used on GRP, FRP, laminate and other composite materials.
Permabond’s flexible epoxies are 2-part systems which cure at room temperature when you mix the resin and hardener. They are available in convenient cartridge packaging for use with static mixer nozzles or in bulk packaging for use on automatic dispensing equipment. Typical hardness is 55-85 on the Shore A scale (20-30 Shore D). Shear strength on carbon fibre is 6-8 MPa (600-1200 psi) and shear strength is 140-160 N/25mm (31-36 PIW).
MT382 modified epoxy is low viscosity and self-levels so can be easily spread or used for potting and encapsulation. In fact, these properties make it very attractive to electronics manufacturers for potting sensitive electronics – its flexibility helps prevent stress on sensitive electronic components as it allows expansion and contraction without cracking. Pot life is 20-50 minutes with handling strength achieved in just under two hours.
MT3821 modified epoxy is a higher viscosity version with good gap fill capability. Pot life is 10-20 minutes with handling time in 60-90 minutes.
Both are colour matched to match carbon fibre for an aesthetically pleasing finished appearance. These materials offer excellent resistance to thermal shock and
For further information please contact Permabond.