The modern method of bonding these materials is to use a hot-melt adhesive. The best performance comes from using reactive hot-melt polyurethanes. These adhesives are applied molten like a conventional hot melt and give instant fixturing with good initial strength (referred to as “green strength”) but then cure slowly by reaction with atmospheric moisture to form a crosslinked thermoset system. The adhesives can be formulated to have different open times and different rates of bond strength buildup. Such adhesives are widely used in the bonding of large panels, such as in insulated garage door construction incorporating polystyrene foam and the walls of recreational vehicles. They are available in cartridges, pails and drums to suit a range of users.

Question: Are cyanoacrylate adhesives thermoplastics?

Answer: Yes. As you probably know, a thermoplastic is a plastic that softens on heating and hardens again on cooling. The problem with using thermoplastics as adhesives is that they have relatively poor heat resistance and they creep under loads. Most cyanoacrylates will soften at about 100°C.There are grades with additives that will improve the heat resistance and monomers, such as allyl cyanoacrylates that have excellent heat resistance after heat curing. Some special toughened cyanoacrylates do act as true structural adhesives, although they tend to be expensive compared to structural epoxies, for example. ASI

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