Light-activated adhesives are used to bond non-transparent materials together without using an additional mechanism to cure the adhesive in the shadowed area between the two substrates.
Whether the adhesive is epoxy or acrylate, the principle is the same: Apply the adhesive to the first substrate, shine a high-intensity light on the adhesive, and bond the second substrate. The adhesive between the substrates will fully cure over time. Optionally, heat can be applied to speed up the curing time (halving the curing time for every 10 degree increase in temperature), or, if adhesive fillets are visible around the edges of the bonded area, further lighting only takes a few minutes. Seconds can significantly increase processing intensity.
Light-activated epoxies have been around for over two decades, but recent innovations have produced light-activated acrylates. While the result is the same, fully cured adhesive between non-transparent parts, the different acrylate chemistry produces a more flexible bond, making it a sensible choice for stress-sensitive applications.
Light-activated adhesives are typically shipped and stored at room temperature, thus avoiding the necessity of using dry ice during shipping (which can significantly reduce shipping costs, while also increasing the number of couriers required to deliver these adhesives). It also means that expensive industrial freezers are not required, reducing energy bills and freeing up valuable storage space within the manufacturing facility.
