PU
421 Topcoat
PU 421 Topcoat is a two-component, high-solids acrylic polyurethane finish formulated for demanding exterior and industrial applications. Its UV-resistant formulation incorporates added light stabilisers to provide excellent colour and gloss retention, weathering resistance and long-term durability.
Available in both clear and pigmented finishes, PU 421 provides excellent clarity in clear form and strong obliteration in pigmented colours. The tough, flexible coating offers high hardness and resistance to mild chemicals, salt water, oils and selected solvents, making it a versatile protective topcoat for steel, equipment, roofing, flooring and other industrial surfaces.
Features & Benefits
- High-solids formulation
Provides efficient film build with excellent protective performance. - 2K acrylic polyurethane technology
Produces a tough, crosslinked finish for demanding service conditions. - UV resistant
Formulated with added light stabilisers for exterior exposure. - Excellent colour retention
Helps maintain pigmented colour during prolonged weathering. - Excellent gloss retention
Maintains a high-quality appearance during exterior service. - Non-chalking
Resists the surface degradation commonly associated with prolonged UV exposure. - Non-yellowing
Particularly important for clear coatings and lighter colours. - Excellent weathering resistance
Suitable for climatic exposure and exterior applications. - High hardness
Provides a durable surface for industrial equipment and trafficable applications. - Excellent flexibility
Combines hardness with the flexibility required for long-term coating durability. - Chemical resistance
Resistant to mild chemicals and dilute industrial chemicals. - Salt-water resistance
Suitable for applications exposed to saline conditions within the coating's service limitations. - Oil resistance
Resists mineral and vegetable oils. - Solvent resistance
Resistant to paraffins and aliphatic solvents. - Unlimited recoatability
Allows the coating system to be maintained or renewed. - Clear or pigmented options
Provides excellent clarity in clear form and excellent obliteration when pigmented. - Multiple application methods
Suitable for airless spray, conventional spray, brush and roller.
Intended Uses
PU 421 Topcoat is designed as a highly durable protective and decorative finish coat for industrial surfaces exposed to weathering, UV radiation, mechanical wear and selected chemicals. In pigmented form it provides excellent obliteration, while the clear version provides excellent clarity where the underlying surface or coating needs to remain visible.
The product can be applied directly to suitably prepared aluminium. Other substrates should receive the appropriate compatible primer or anti-corrosive coating system before application. Its combination of high colour stability, weathering resistance, hardness and chemical resistance makes PU 421 suitable for a broad range of exterior and industrial protective coating systems.
Typical Applications:
- Structural steel
- Agricultural equipment
- Earthmoving equipment
- Construction equipment
- General plant and machinery
- Industrial equipment
- Aluminium components
- Fabricated metal components
- Roof coatings
- Floor coatings
- Industrial floors
- Line demarcation
- Wall coatings
- Protective concrete coating systems
- Trafficable surfaces
- Self-levelling epoxy floors
- Self-levelling polyurethane floors
- UV-protective topcoats over epoxy systems
- UV-protective topcoats over polyurethane systems
- Industrial maintenance
- Exterior protective coating systems
- Equipment refurbishment
Technical Information:
- Product Type: High-solids acrylic polyurethane topcoat
- Technology: Two-component acrylic polyurethane
- Category: Industrial & Protective – Steel & Concrete Protection – Climatic
- Colour: Clear and pigmented
- Finish: High gloss
- Density: Approximately 1 kg/L
- Mass Solids – Clear: 58% ±3%
- Volume Solids – Clear: 57% ±3%
- Volume Solids – White: 67% ±3%
- Mixing Ratio: 4:1 by volume
- Activator: PU Activator 90 AL XL
- Typical Film Thickness: 35–60 µm DFT per coat
- Typical Total Film Thickness: 70–120 µm DFT, depending on specification
- Theoretical Coverage – White: Approximately 9.5 m²/L at 60 µm DFT, before allowance for loss factors
- Application Methods: Airless spray, conventional spray, brush or roller
- Pot Life at 25°C: 1 hour
- Airless Spray Tip: 11–17 thou
- Minimum Airless Pressure: 140 bar / 2000 PSI
- Conventional Spray: Gravity feed
- Conventional Spray Fluid Tip: 1.1–1.6 mm
- Thinner: PU Thinner
- Thinning: 0–20%, depending on application
- Cleaner: SA65 Thinner
- Typical Brush/Roller Film Build: 40–50 µm
- Touch Dry at 25°C: Approximately 1 hour
- Hard Dry at 25°C: Approximately 4 hours
- Minimum Overcoating Time at 25°C: 4 hours
- Minimum Surface Temperature: 3°C or 3°C above dew point
- Maximum Surface Temperature: 45°C
- Minimum Ambient Temperature: 5°C
- Maximum Ambient Temperature: 45°C
- Maximum Relative Humidity: 85%
- Pack Size: 5 L
- Shelf Life – Part A: Minimum 24 months at 25°C, subject to inspection thereafter
- Shelf Life – Part B: Minimum 12 months at 25°C, subject to inspection thereafter
Colours & Finishes
Clear Gloss
Pigmented Gloss
Please Note: Colour swatches and illustrations displayed are only to be used as a guide and can vary from the original.
Documents & Resources
Industrial Protective Coatings
Tell Us More About Your Project
