Cross-Examining Crosslinkers

American powder coaters: it’s time for us to get acquainted with our crosslinkers.

The crosslinker is responsible for causing polymer chains to link during the curing process. In other words, it’s the chemical agent that transforms the grainy powder we spray into the smooth coating that our customers know and love.

If you’re anything like me, the vast majority of the powder you’ve sprayed in your career has featured a TGIC crosslinker, and no wonder: historically, TGIC has been the darling of the powder industry. It’s cheap to manufacture, and provides durable coating results. 

TGIC’s global popularity took a nosedive in 1998, however, when it was banned in Europe for causing genetic defects if handled without proper protective equipment. Though we’re decades behind Europe, the US is moving in a similar direction – I predict that it won’t be long before TGIC powders are a rarity on our shop shelves, and HAA powders (which are much safer to manufacture) become the new normal.

Rest assured that this change will have zero impact on the powder coating’s color and gloss retention. HAA powder coating is every bit as weatherable as TGIC powder coating, and HAA powder coating actually offers a smoother, better-looking finish. There should also be very little difference in price point: as production of HAA powders has increased, their cost has become very comparable to TGIC powders.

If anything, switching to HAA powder coating will save your shop (and mine) a little bit of money. HAA powder coating cures at a slightly-lower temperature than TGIC powder coating, meaning that our ovens don’t have to work as hard. In fact, beware of overbaking – due to its lower curing temperature, HAA powder coating is less resistant to overbaking than the old TGIC powders were. Plan for lower oven temperatures and/or shorter curing times.

In addition to modest energy savings, we’ll also see a 10-20% increase in transfer efficiency over TGIC powders. This means 10-20% less wasted powder on the floor of our spraying booths. Over time and with enough volume, this translates to money saved.

A word of warning: HAA powders are slightly less chemically-resistant than TGIC powders. I plan to educate Kaser’s customers on this point – the more cautious they are with solvents, the more long-term satisfaction they’ll derive from their coating.

Please also note that while TGIC powders could formerly be applied up to 8-10 mils per coat, HAA manufacturers typically recommend a 4 mil maximum thickness per coat. Any thicker, and you will likely encounter outgassing. For best results, consider applying several thinner coats, as opposed to a single, thick coat.

All things considered, I look forward to this inevitable industry shift. May the future of powder coating bring cost savings and heightened transfer efficiency to us all.

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