Arccoil PR 250 Epoxy-Modified Primer and Backing Coat
A chromate-free epoxy-modified coil primer applied at 5 to 8 microns for systems where corrosion resistance and cut edge performance rank above forming latitude, and the matched primer under Arccoil PV topcoats. The same binder is supplied as a reverse-face backing coat in a blocking-resistant version and a polyurethane foam-adhesion version.
Grade Arccoil PR 250 | Range Coil and Extrusion Coatings | Technology Solvent-borne chromate-free epoxy-modified primer and backing coat
Technical Data Sheet
Arccoil PR 250
Issue 2026.09
1. Product description
A chromate-free epoxy-modified primer at five to eight microns, for systems where corrosion resistance and cut edge performance rank above the widest possible forming latitude, and the matched primer under Arccoil PV topcoats. The same binder is supplied as a reverse-face backing coat, in a blocking-resistant version for recoiled stock and in a version formulated for adhesion to a polyurethane foam core in sandwich panel production. Selecting the reverse-face variant is a separate decision from the primer and has to be made when the coil is ordered.
2. Features
- Chromate-free epoxy-modified binder selected for corrosion resistance and cut edge performance
- Matched primer under Arccoil PV fluoropolymer topcoats
- Blocking-resistant backing coat version for recoiled stock
- Foam-adhesion backing coat version for sandwich panel facings
- Reverse-face variant is selected separately, when the coil is ordered
3. Recommended uses
Primer under Arccoil PV and Arccoil SP topcoats for cladding, rainscreen and roofing sheet where corrosion and cut edge performance lead the specification. As a backing coat, it serves the reverse face of recoiled stock and of polyurethane foam-cored sandwich panels.
Substrates. Hot-dip galvanised steel, zinc-aluminium alloy coated steel and aluminium strip; the foam-adhesion variant is used on the reverse face of sandwich panel facings.
4. Typical properties
| Property | Typical value | Method |
|---|---|---|
| Technology | Solvent-borne chromate-free epoxy-modified primer and backing coat | Formulation |
| Supply form | Pigmented liquid for roll coating, supplied as primer, blocking-resistant backing coat or foam-adhesion backing coat | Customer or supplier protocol |
| Dry film thickness | 5 to 8 microns per face, front and reverse | EN 13523-1; ASTM D7091 for the magnetic induction or eddy current check on the line |
| Peak metal temperature at oven exit | 216 to 232 degrees Celsius in the first oven under polyester and silicone-modified polyester topcoats; 232 to 249 degrees Celsius under a PVDF topcoat, whose cure the primer also sees. Where the backing coat is applied at the reverse-face station of the finish coater, it is cured in the second oven at the peak metal temperature set for the front-face topcoat. | Strip-attached thermocouple or peak metal temperature recorder read on the line; a line measurement, as there is no dedicated published test standard |
| Solvent resistance, methyl ethyl ketone double rubs | 50 to 100 double rubs without exposure of the metal substrate, the count agreed for the system, used as a cure check on the primed or backed strip | EN 13523-11, ASTM D5402 |
| Cross-cut adhesion, finished system | Classification 0, no removal at the cut edges or intersections | ISO 2409 |
| Neutral salt spray resistance, finished system | 500 to 1000 hours with creep from the scribe not more than 2 mm and no field blistering, set by the system chemistry and film build | ISO 9227, ASTM B117, EN 13523-8 |
| Blocking and pressure marking, blocking-resistant backing coat | No transfer or face damage after the agreed time at 50 degrees Celsius under the agreed pressure, commonly 1 to 4 hours | EN 13523-24 |
| Foam adhesion, foam-adhesion backing coat | Failure in the foam rather than at the coating interface, at the peel strength agreed with the panel maker | EN 13523-20 |
Typical values, not a specification. Values for each batch are given on its Certificate of Analysis.
5. Application
| Parameter | Guidance |
|---|---|
| Application method | Roll coating at the prime coater, front and reverse face; the backing coat is applied at the reverse-face station of the finish coater where the line is configured that way |
| Surface preparation | Strip cleaned, rinsed, chemically pretreated and dried on the line; a clean, correctly weighted conversion coating is required, as no primer recovers a contaminated or under-treated strip |
| Viscosity adjustment | Hold the supply at the agreed viscosity and coater temperature; correct with the supplied thinner only, to the supplied ratio |
| Applied film | 5 to 8 microns dry per face; check thickness at both edges and the centre of the strip |
| Cure | 216 to 232 degrees Celsius peak metal temperature in the first oven under polyester and silicone-modified polyester topcoats, or 232 to 249 degrees Celsius under a PVDF topcoat, then quench. Where the backing coat is applied at the reverse-face station of the finish coater, it is cured in the second oven at the peak metal temperature set for the front-face topcoat. |
| Next step | Arccoil PV 510, Arccoil PV 550 or Arccoil SP topcoat at the finish coater; confirm the strip is cool enough at the recoiler for the backing coat specified |
| Ordering | Specify the reverse-face duty, blocking resistance or foam adhesion, when the coil is ordered |
Process. Roll coated at five to eight microns dry, front face and reverse face, cured in the first oven to a peak metal temperature of 216 to 241 degrees Celsius and quenched. Under a fluoropolymer topcoat the primer is cured to the PVDF window of 232 to 249 degrees Celsius, because it sees the peak metal temperature the topcoat needs. The backing coat is applied at the reverse-face station of the finish coater where the line is configured that way.
6. Storage and handling
Store in the original, tightly closed containers in a cool, dry, covered area away from direct sunlight and heat, and stir to a uniform consistency before use. Shelf life is stated on the label and Certificate of Analysis. Handle and use the product in line with its Safety Data Sheet.
7. Safety and regulatory information
Read the Safety Data Sheet before use. Safety Data Sheets and regulatory declarations are issued by our technical centre against the product and batch supplied, so they are sent on request rather than published. Request a Safety Data Sheet or declaration.
This Technical Data Sheet is published for on-screen reference. The information is given in good faith from laboratory and application experience and describes typical values; it is not a specification and does not replace a trial on your own substrate and line. Arctic Materials may revise this sheet without notice. Issue 2026.09.
Technical Data Sheets on this site are for on-screen viewing. For a controlled copy, write to tech@arcticmaterials.com.
Other grades in this range
Need a Safety Data Sheet, a regulatory declaration or a grade specified to your line? Contact our technical centre.