Fast and highly durable plastics bonding

19th May 2021

Henkel

Alex Lynn

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New plastics bonding technology is bringing significant benefits to the assembly of products requiring multi-material and multi-substrate bonds with stringent performance criteria. The technical complexity of the application can often constrain the manufacturer’s ability to boost productivity to meet increased product demand but a new, patented hybrid technology is allowing many to address these issues.

Developed by Henkel, the LOCTITE HY 4090 is a new breed of adhesive that combines the fixture speed of an instant adhesive – also known as a cyanoacrylate – with the durability of an epoxy. This combination has opened-up new application areas for an instant adhesive in structural bonding and particularly applications where production speed is a major consideration.

A good example of this technology’s merits is in the assembly of battery packs for electrical devices. To meet the projected production line volumes of a new product, the manufacturer sought an adhesive that was able to bond polyamide (PA) with a thermoplastic polymer (ABS), at speed. The resultant bond also needed to be resistant to operational fluctuations in vibration, temperature and humidity.

LOCTITE HY 4090 proved the perfect candidate. This two-part hybrid has all the speed and material versatility of a classic instant adhesive plus high temperature-performance and moisture/chemical resistance. It is suitable for temperatures up to 150^oC and suited for bonding highly stressed joints and those that are exposed to vibration.

Having cleaned the battery pack parts with LOCTITE SF 7063 to remove moulding compounds that may inhibit final bond strength, LOCTITE HY 4090 is then dispensed from a dual cartridge pack using a manual hand gun with mixer nozzle. The hybrid adhesive fixtures in just three minutes, minimising any potential blooming from exposed fillets of the cyanoacrylate-based product.

Epoxy-based adhesives are proven to provide exceptional static and dynamic strength and are the traditional choice for demanding structural bonding applications such as this. However, this technology typically requires a minimal fixture time of ten minutes. By choosing LOCTITE HY 4090 the manufacturer has the best of both worlds – its suitability for bonding load bearing parts and achieving handling strength in minimum time.

These qualities have allowed the manufacturer to significantly increase productivity while underpinning product quality.