INTERIOR TOPCOAT 578

What is ALEXSEAL Interior Topcoat 578 and why choose it?

ALEXSEAL Interior Topcoat 578 is a two-component, polyurethane-based interior coating designed for professional use where an extremely durable, long-lasting finish is required. It offers very good adhesion on a wide range of substrates, including difficult surfaces such as aluminum, and delivers high resistance to abrasion, scratching, solvents, chemicals, synthetic cooling agents and hydraulic oils. The product is intended for interior applications and has low flame-spread characteristics approved according to IMO Resolution MSC.307 (88) (FTP-Code 2010), making it suitable for demanding marine environments.

Main features

• Two-component polyurethane system for robust, long-term interior protection.
• High chemical and mechanical resistance to abrasion, scratching, solvents, chemicals, synthetic cooling agents and hydraulic oils.
• Excellent adhesion on properly cleaned and pretreated substrates, including aluminum and other hard-to-coat materials.
• Interior marine approval with low flame-spread characteristics in accordance with IMO Resolution MSC.307 (88) (FTP-Code 2010).
• Can be applied by spray, brush or roller with defined film thickness ranges for each method.
• Good coverage with 63 percent solids by volume (catalyzed without reduction) and optimized spread rates for different application techniques.
• Professional-grade workability with adjustable reduction levels and defined pot life and drying times across a range of temperatures.
• Available in factory packaged colors for interior yacht and engine room applications.

Technical specifications

Product type and composition

• Type: Two-component polyurethane interior topcoat.
• Chemical nature: Mixture of synthetic resins, organic solvents and pigments.
• Solids by volume (catalyzed, without reduction): 63 percent.
• VOC content (Directive 2010/75/EU): 36.11 percent, 487 g per liter (excluding water).
• Physical state: Liquid.
• Odour: Characteristic.
• Density: Approximately 1.35 g per cm³ at 20 °C.

Color range

• Supplied in standard factory packaged colors.
• Specific color references: Consultar ficha técnica del fabricante.

Recommended uses

• Parts in the engine room.
• Yacht interior areas.
• Industrial serial painting (as indicated in the safety data sheet).

Coverage and film thickness

Coverage values below refer to applications with two coats. Reducer is added as a percentage of the total quantity of base plus converter.

• Theoretical coverage (brush and roller): 8 m² per liter; 30.3 m² per gallon; 326 sq. ft. per gallon at 35–45 µm DFT.
• Conventional air spray: 5 m² per liter; 19 m² per gallon; 204 sq. ft. per gallon at 35–45 µm DFT.
• HVLP air spray: 6 m² per liter; 22.7 m² per gallon; 244 sq. ft. per gallon at 35–45 µm DFT.
• Airless spray equipment: 8 m² per liter; 30.3 m² per gallon; 326 sq. ft. per gallon at 35–45 µm DFT.

Substrate preparation

• Substrate must be clean, dry and free from dust, grease, oil and other contamination.
• Can be applied directly to appropriately cleaned and pretreated substrates, including difficult substrates such as aluminum.
• For optimum corrosion protection, the use of ALEXSEAL Interior Primer 178 or a suitable primer may be required.

Trade names and packaging

• Base: ALEXSEAL Interior Topcoat 578 (Base Color) – 1 gallon.
• Converter: C6402 ALEXSEAL Interior Topcoat Converter – 1 quart.
• Reducers:
  • R6062 ALEXSEAL Interior Topcoat Reducer – 1 gallon.
  • R6068 ALEXSEAL Interior Topcoat Reducer Slow – 1 gallon.

Mixing ratios

• Spray application:
  • 4 parts by volume ALEXSEAL Interior Topcoat 578 (Base Color).
  • 1 part by volume C6402 ALEXSEAL Interior Topcoat Converter.
  • 20–30 percent by volume R6062 ALEXSEAL Interior Topcoat Reducer and or R6068 ALEXSEAL Interior Topcoat Reducer Slow.
  • Example ratio: 4 : 1 : 1 to 1.5 (20–30 percent reduction).
• Brush and roller application:
  • 4 parts by volume ALEXSEAL Interior Topcoat 578 (Base Color).
  • 1 part by volume C6402 ALEXSEAL Interior Topcoat Converter.
  • 10–15 percent by volume R6062 ALEXSEAL Interior Topcoat Reducer and or R6068 ALEXSEAL Interior Topcoat Reducer Slow.
  • Example ratio: 4 : 1 : 0.5 to 0.75 (10–15 percent reduction).
• The amount of reducer required may vary depending on application conditions.
• Mixed material must be filtered before application.

Application parameters

• Viscosity:
  • Zahn No. 2: approximately 15–18 seconds.
  • DIN 4 cup 4 mm: approximately 12–18 seconds.
• Spray equipment set-up (Conventional and HVLP):
  • Nozzle size gravity gun: 1.2–1.6 mm (0.047–0.060 in).
  • Fluid nozzle size pressure pot: 1.0–1.3 mm (0.040–0.050 in).
  • Atomizing pressure: 3.0–5.0 bar (42–70 psi).
  • Pot pressure: 0.7–1.5 bar (10–20 psi).
• Airmix equipment:
  • Nozzle: 0.18–0.28 mm (0.007–0.011 in).
  • Inlet pressure: 3.0–5.0 bar (42–70 psi).

Recommended film thickness and coats

Spray application

• Apply 2 coats to a wet film thickness (WFT) of 50–75 µm (2–3 mils) per coat.
• Flash time between coats: 20–60 minutes.
• Resulting dry film thickness (DFT) for 2 coats: 30–50 µm (1.5–2 mils).
• Maximum recommended during spray application: 2 coats totaling 180–220 µm (7–9 mils) WFT, corresponding to 60–70 µm (2.5–3 mils) DFT.

Brush and roller application

• Apply 2–3 coats to a WFT of 25–37.5 µm per coat.
• Each coat should dry to tape-dry stage in 12–24 hours.
• DFT for 2-coat application: 25–37.5 µm.
• DFT for 3-coat application: 35–45 µm.

Environmental and drying conditions

• Optimal application environment: 15–30 °C (60–85 °F), 40–80 percent relative humidity.
• During drying, minimum temperature: 15 °C (60 °F).
• Ideal temperature: 25 °C (77 °F).
• Minimum application condition: 3 °C (5.4 °F) above dew point.

Pot life and drying times

Approximate values depending on temperature:

• Pot life:
  • 15 °C (60 °F): 18 hours.
  • 20 °C (68 °F): 12 hours.
  • 25 °C (77 °F): 9 hours.
  • 30 °C (85 °F): 6 hours.
• Dust free:
  • 15 °C: 40–60 minutes.
  • 20 °C: 30–45 minutes.
  • 25 °C: 20–30 minutes.
  • 30 °C: 15–20 minutes.
• Tape dry:
  • 15 °C: 32 hours.
  • 20 °C: 24 hours.
  • 25 °C: 16 hours.
  • 30 °C: 12 hours.
• Fully cured:
  • 15 °C: 14 days.
  • 20 °C: 7 days.
  • 25 °C: 5 days.
  • 30 °C: 3 days.
• Recoat with ALEXSEAL Interior Topcoat 578 (spray application) after tack-up:
  • 15 °C: 40–60 minutes.
  • 20 °C: 30–45 minutes.
  • 25 °C: 20–30 minutes.
  • 30 °C: 15–20 minutes.
  • Maximum recoat window: 4 hours.
• Overcoating with another product (surface preparation including sanding required):
  • 15 °C: 24 hours.
  • 20 °C: 24 hours.
  • 25 °C: 18 hours.
  • 30 °C: 12 hours.

Key physical and safety-related properties

• Boiling point range: approximately 120 °C.
• Flash point: 28 °C (ISO 13736).
• Auto-ignition temperature: greater than 400 °C.
• Upper explosion limit: 10 percent by volume.
• Lower explosion limit: 1 percent by volume.
• Water solubility: insoluble; immiscible with water.
• Solvent separation: less than 3 percent by volume.

Applications and use cases

• Engine rooms: Durable interior coating for components and structures in engine compartments where resistance to oils, chemicals and mechanical wear is required.
• Yacht interiors: High-performance finish for interior panels, structural parts and surfaces needing a robust, easy-to-clean coating with low flame-spread characteristics.
• Industrial serial painting: Suitable for professional industrial painting processes where a solventborne polyurethane interior topcoat is specified.

FAQ

1. Is ALEXSEAL Interior Topcoat 578 suitable for exterior use?

No. This coating is recommended for interior applications only. Objects exposed to extreme weather and UV radiation may show gloss and color changes; however, this does not affect the protective properties of the film.

2. On which substrates can this product be applied?

The product can be applied directly on appropriately cleaned and pretreated substrates, including difficult-to-coat surfaces such as aluminum.

3. Do I need a primer before applying Interior Topcoat 578?

For optimum corrosion protection, the use of a suitable ALEXSEAL primer, such as ALEXSEAL Interior Primer 178, is recommended, particularly on metallic substrates.

4. How many coats are recommended?

For spray application, 2 coats are recommended. For brush or roller application, 2–3 coats are recommended, depending on the target dry film thickness.

5. What is the typical pot life of the mixed product?

Pot life varies with temperature: approximately 18 hours at 15 °C, 12 hours at 20 °C, 9 hours at 25 °C and 6 hours at 30 °C.

6. How long does it take for the coating to fully cure?

Full cure is reached after approximately 14 days at 15 °C, 7 days at 20 °C, 5 days at 25 °C or 3 days at 30 °C.

7. Can I overcoat ALEXSEAL Interior Topcoat 578 with another product?

Yes. Overcoating with another product is possible after the specified minimum times, but surface preparation including sanding is required.

8. Is this product flammable?

Yes. It is classified as a flammable liquid, Category 3. It has a flash point of 28 °C and should be kept away from heat, hot surfaces, sparks, open flames and other ignition sources.

9. Is the product hazardous to the environment?

It is classified as toxic to aquatic life with long lasting effects. Avoid release to the environment and prevent the product from entering drains or water courses.

10. Who is this product intended for?

ALEXSEAL Interior Topcoat 578 is for professional use only and should be applied by trained personnel following appropriate safety and handling guidelines.

Section 14: Transport information

• UN number: UN 1263.
• UN proper shipping name: PAINT.
• Transport hazard class: Class 3 (flammable liquids) for ADR, IMDG and IATA.
• Packing group: III.
• ADR details:
  • Classification code: F1.
  • Hazard identification number: 30.
  • Labels: 3.
  • Tunnel restriction code: D E.
  • If transported within the user’s premises: always transport in closed, upright and safe containers, and ensure that personnel are aware of procedures in case of incident or spillage.
• IMDG details:
  • Labels: 3.
  • EmS code: F-E, S-E.
  • Marine pollutant: yes.
• IATA details:
  • Packing instruction cargo aircraft: 366; packing group III; label Flammable Liquids.
  • Packing instruction passenger aircraft: 355; packing instruction limited quantities (LQ): Y344; packing group III; label Flammable Liquids.
• Environmental hazards in transport:
  • ADR: environmentally hazardous – yes.
  • IMDG: marine pollutant – yes.
• Maritime transport in bulk according to IMO instruments: not applicable for product as supplied.

Section 8: Personal protective measures

Engineering controls

• Provide adequate ventilation using local exhaust and general extraction to keep solvent and aerosol concentrations below occupational exposure limits.
• Where ventilation is insufficient, suitable respiratory protection must be used.

Eye and face protection

• Wear safety goggles to protect against solvent splashes.

Hand protection

• Use appropriate chemical-resistant protective gloves tested according to EN 374.
• Recommended glove materials for splash protection: nitrile rubber or neoprene.
• Minimum glove thickness: greater than 0.4 mm.
• Breakthrough time: greater than 480 minutes.
• Before use, verify glove suitability for the specific workplace conditions and observe the manufacturer’s instructions for use, storage, care and replacement.
• Replace gloves immediately if damaged or worn and avoid continuous, unnecessary glove use by designing operations appropriately.

Skin and body protection

• Depending on the probability of dangerous explosive atmospheres, wear suitably adapted protective clothing.
• Preventive hand protection with skin protection cream and prompt washing of contaminated skin are recommended.

Respiratory protection

• If exposure levels may exceed limits, use appropriate, certified respirators.
• Use a half-mask respirator with suitable cartridge or an air-fed system.
• During dry grinding, torch cutting or welding on coated surfaces, hazardous dust or vapour can be generated; if possible, use wet methods and exhaust hoods to capture vapours and fumes.
• When operators must work inside a spray booth, a compressed air-fed respirator is recommended during spraying until particulate and solvent vapour concentrations fall below the exposure limits.

General protective measures

• Do not eat, drink or smoke during work.
• Avoid contact with skin, eyes and clothing.
• Avoid inhalation of sanding dust, particulates and spray mist.