Arcmotive EX 370 High-Build Exterior Clearcoat
A two-component high-build aliphatic clearcoat applied wet on wet over Arcmotive EX 320 basecoat. It is specified where exterior trim calls for the upper end of the weathering window, a full gloss finish and resistance to car wash brushes, screen wash and fuel splash.
Grade Arcmotive EX 370 | Range Automotive Coatings | Technology Two-component high-build aliphatic clearcoat
Technical Data Sheet
Arcmotive EX 370
Issue 2026.09
1. Product description
A two-component high-build aliphatic clearcoat applied over EX 320 basecoat where the specification calls for the longest weathering hours, a full gloss finish and resistance to car wash brushes, screen wash and fuel splash. The higher film build and the higher crosslink density lift scratch resistance and thermal cycling performance above the solid colour route. It is the grade used when exterior trim must match a body panel clearcoat in appearance and durability.
2. Features
- High film build and higher crosslink density raise scratch resistance and thermal cycling performance above the solid colour route
- Full gloss finish matched to a body panel clearcoat in appearance
- Resistance to car wash brushes, screen wash and fuel splash
- Applied wet on wet over flashed EX 320, with basecoat and clearcoat cured together
3. Recommended uses
Exterior trim such as mirror housings, grilles, pillar covers and body-side mouldings where the part must match a body panel clearcoat in appearance and durability.
Substrates. Applied over Arcmotive EX 320 basecoat on ASA, PC/ABS, polyamide and treated polypropylene.
4. Typical properties
| Property | Typical value | Method |
|---|---|---|
| Technology | Two-component high-build aliphatic clearcoat | Formulation |
| Appearance and finish | Clear, full gloss film | Customer or supplier protocol, visual assessment against the approved master panel |
| Dry film thickness | 35 to 45 micrometres | ISO 2808 |
| Specular gloss at 60 degrees | Held to the approved master panel, typically within plus or minus 3 units | ISO 2813 |
| Cross-cut adhesion, initial and after ageing | Classification 0 to 1 with no flaking at the cut intersections, held after humidity, thermal cycling and chemical exposure | ISO 2409 |
| Pencil hardness | F to 2H | ISO 15184 |
| Accelerated weathering, xenon arc with filtered daylight | 1000 to 2500 hours depending on the customer protocol, with gloss and colour within the agreed limit; this grade is used where the protocol sits at the upper end of that window | ISO 16474-2, or ISO 4892-2 where the protocol is written against the moulding |
| Colour difference after weathering, EX 320 and EX 370 system | Delta E star ab typically below 1.5 against the approved master panel | ASTM D2244 |
| Chemical spot resistance, screen wash and fuel | Contact time and temperature for each reagent as set in the customer protocol, within 1 to 24 hours at 23 to 80 degrees Celsius; fuel and screen wash are spotted at 23 degrees Celsius and covered to limit evaporation, with no staining, softening, gloss change or adhesion loss | ISO 2812-4 |
| Temperature cycling | 10 cycles between minus 40 and 90 degrees Celsius with adhesion held and no blistering, cracking or flaking | Customer protocol cycle, assessed to ISO 2409 and ISO 4628-1 to ISO 4628-5 |
Typical values, not a specification. Values for each batch are given on its Certificate of Analysis.
5. Application
| Parameter | Guidance |
|---|---|
| Mixing | Mix at the stated ratio, allow the stated induction time and use within the pot life, typically 3 hours at 25 degrees Celsius. Never return mixed material to the pot. |
| Substrate | Arcmotive EX 320 basecoat on ASA, PC/ABS, polyamide and treated polypropylene, after its 8 to 12 minute flash off and with no intermediate bake. |
| Application method | Spray, wet on wet over the flashed basecoat. |
| Dry film thickness | 35 to 45 micrometres. |
| Flash off and cure | Flash off 10 minutes, then cure basecoat and clearcoat together for 30 to 40 minutes at 80 degrees Celsius part temperature, measured with a data logger travelling with the part. |
| Quality control | Read gloss at 60 degrees and colour against the approved master panel, and check adhesion on a witness panel run with the parts. |
| Safety and handling | Refer to the Safety Data Sheet, issued on request against the product supplied. |
Process. Applied wet on wet over flashed EX 320 basecoat at 35 to 45 micrometres dry. Pot life 3 hours at 25 degrees Celsius. Flash off 10 minutes, then cure basecoat and clearcoat together for 30 to 40 minutes at 80 degrees Celsius part temperature.
6. Storage and handling
Store base and hardener in their original closed containers in a cool, dry, well-ventilated store, out of direct sunlight and away from sources of heat, and keep the hardener tightly sealed because it reacts with atmospheric moisture. Shelf life is stated on the label and the 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.