High Temperature Cured PPGL Steel Coil with Uniform Gloss Finish

High Temperature Cured PPGL Steel Coil with Uniform Gloss Finish

Cure is the least visible part of coil coating and the most decisive. If the peak metal temperature is too low, the resin never fully cross links: the coil feels dry, passes a casual inspection, and then fails in service with poor adhesion, blocking in the stack, or a rapid gloss drop in the first summer. This PPGL coil is cured at a controlled peak metal temperature with the profile logged per coil, so full cure is a measured fact rather than an assumption.

Uniform gloss is the visible consequence. A coil that is under cured in the middle of the strip width will show a gloss band when the panel is formed, and that band is exactly the defect a client notices on a new facade.

Coil Specification

What Full Cure Gives You

• Adhesion that holds after water soak, not just on the day of coating.
• No blocking when coils are stacked or shipped warm.
• Uniform gloss across the strip width, so formed panels match.
• MEK resistance confirming cross link density rather than surface dryness.
• Slower gloss loss in the first two years of exterior exposure.

Applications

• Exterior wall and roof panels with visible gloss requirements
• Panels formed after coating, where cure affects bend behaviour
• Export shipments with long sea transit and stacked coils
• Projects where adjacent panels must match in sheen

Buyer Questions

How do you prove the coil is fully cured?

With an MEK double rub test and a pencil hardness reading on samples from both edges and the centre of the strip. Both are recorded on the inspection sheet for the coil you receive.

Why does cure affect blocking?

Under cured coating stays slightly tacky, so when coils are stacked or shipped in a warm container the laps stick together and the surface tears on uncoiling. Full cure removes that risk.

Can you match gloss to an existing installation?

Yes. Send a sample panel and we target its measured gloss, then verify across the width of the first production coil.

Does higher cure temperature affect color?

It can if the oven is overshot, which yellows pale shades. That is why the profile is controlled within a band rather than simply maximised.

Packing and Traceability

Coils are wrapped in PVC film with paper interleaving, strapped on wooden pallets and labelled with heat number, coating batch and the recorded peak metal temperature. Keeping the cure data on the label means a fabricator facing a forming or adhesion issue can check the process record immediately.

Cure Record

Every coil ships with the logged peak metal temperature and the MEK and hardness readings taken from both edges and the centre of the strip. If a fabricator later reports adhesion or forming trouble, the record answers the first question immediately: was the coil cured, and was it cured evenly across its width.

The substrate is Aluzinc AZ100 - AZ150. The AZ designation describes the aluminium-zinc alloy coating weight, which is what gives cut edges and drilled holes their sacrificial protection. A higher coating weight extends time to red rust, but it also changes forming behaviour, so the grade should be matched to the exposure class of the finished building.

Coating thickness matters more than coating brand in service: Top 22 - 28 micron, primer 5 micron. Below roughly 20 micron total build, UV exposure in strong sun starts to chalk the surface within a few years, and the colour drifts before the steel itself shows any problem.

Formability is specified as T bend 2T without cracking. This determines whether the strip can be roll formed and folded at the job site without cracking the coating over the bend radius, which is the most common cause of premature coating failure on roofing panels.