Aerospace adhesives that fly further

Sometimes a product is born when businesses see a demand in the market. Other times, people come to you with a demand you didn't know existed. Permabond ET5422, a pioneering two-part epoxy purpose-built for the aerospace industry, is one such case.

It all began when a customer in the industry approached Permabond with a project. The company was looking for an adhesive to bond lightweight composite components for aircraft seating. The customer was insistent on using no fasteners or fixings in the seats, as they wanted to keep weight as low as possible. The adhesive chosen needed to be rugged and able to withstand torsion forces.

It had already tried Permabond ET5429, a two-part epoxy with great performance on composite materials. ET5429 has a peel strength of 230 N/25mm (52 PIW), already incredibly high for an epoxy (standard epoxies have a peel strength of around 25 N/25mm (6 PIW)). And while the company liked this product, it wanted something even stronger - a product that, at the time, Permabond did not have.

Unmatched peel strength

Epoxies lend themselves especially well to customisation, with things like viscosity, cure speed and heat resistance all relatively straightforward to tailor to a customer's individual requirements. Permabond ET5422 started its life as one such custom-made product.

Since strength was the aerospace customer's main goal, Permabond made ET5422 to have a peel strength of 320 N/25mm (70 PIW). With this level of strength, the customer was very satisfied, with the product passing all necessary testing and soon rolled out into production.

Due to the success of this product, it's now being made available to the market as a whole. This means market sectors like automotive, general assembly and composite markets such as prosthetics and sports equipment can all access this exceptionally strong aerospace-grade adhesive at the click of a button.

Permabond ET5423 - the same benefits in black

Permabond ET5422 is blue, as per the original customer's wishes. Since Permabond can easily customise epoxies, it decided to make a black version - Permabond ET5423. This adhesive provides all the same benefits of ET5422 but colour matched for seamless bonding of carbon fibre and other dark substrates. Permabond also sells an unpigmented version of this product.

In addition to outstanding peel strength, ET5422 and ET5423 offer an array of other benefits. First is their high resistance to impact and vibration due to their rubber toughening. This makes them very well suited to automotive and aerospace applications where impact, vibration and general bond stress are commonplace.

Both products are thixotropic with excellent flow control properties. This, combined with their ease of mixing and dispensing, makes them ideal for gap filling applications. And in addition to bonding composite materials well, they also bond to a variety of metals including aluminium and stainless steel - this includes bonding dissimilar substrates such as stainless steel to carbon fibre.

Permabond ET5424 - your friend for space-based applications

Just as ET5422 was initially designed for aircraft, Permabond ET5424 was conceived for space industries. It excels in this field for two main reasons: its high heat resistance and low-outgassing formulation.

Permabond ET5424 can withstand up to 230degC and has a Tg of 182degC. This not only makes it highly suited to applications subjected to high temperatures, but also good for paint baking and powder coating applications. The cured adhesive will withstand the oven heating process of paint baking well, ensuring a smooth, even finish.

Where ET5424 really shines as an aerospace adhesive, however, is its low-outgassing properties. This adhesive has been tested to ECSS-Q-ST-70-02C, a thermal outgassing test for the screening of space materials. In a vacuum such as space, cured adhesives can give off vapours (outgassing) which can build up on sensitive components like optics, sensors or solar panels, affecting their performance. Permabond ET5424's low-outgassing formulation helps to prevent this build-up and keeps components performing as they should.

Similarly to ET5422 and ET5423, Permabond ET5424 is thixotropic with good flow control, and bonds a wide variety of metals and composites, including dissimilar substrates. It also has reduced hazards on its SDS, allowing for a safer, more comfortable working environment.