What is ALEXSEAL Interior Topcoat 578 Converter and why choose it?
ALEXSEAL Interior Topcoat 578 Converter (C6402) is a polyisocyanate-based hardener specifically formulated for use with ALEXSEAL Interior Topcoat 578. As part of this two-component polyurethane system, the converter ensures an extremely durable, long-lasting interior coating with excellent adhesion and high resistance values. When correctly mixed with the base color and reducer, it delivers a cured film resistant to abrasion, scratching, solvents, chemicals, synthetic cooling agents and hydraulic oils, making it suitable for demanding marine interiors and engine room components.
This converter is intended for professional and industrial use, especially in environments where robust interior protection, controlled application properties and compliance with marine regulations are required.
Main features
- Dedicated converter for ALEXSEAL Interior Topcoat 578: Designed to react with the base color and create a tough polyurethane coating.
- High durability of the final system: In combination with the base topcoat, the cured film shows high resistance to abrasion, scratching, solvents, chemicals, synthetic cooling agents and hydraulic oils.
- Suitable for interior marine environments: Used for parts in the engine room and yacht interiors when mixed with ALEXSEAL Interior Topcoat 578.
- Controlled application behavior: Supports spray, brush and roller application when used at the specified mixing ratios with the recommended reducers.
- Professional-grade formulation: Hardener based on polyisocyanates, developed for industrial serial painting processes.
- Regulatory status of the complete system: The ALEXSEAL Interior Topcoat 578 system is approved by IMO Resolution MSC.307 (88)-(FTP Code 2010) as a marine paint with low flame-spread characteristics.
Technical characteristics
Chemical and physical properties (converter C6402)
- Chemical nature: Hardener based on polyisocyanates.
- Appearance: Liquid.
- Color: According to product name.
- Odor: Characteristic.
- Boiling range: Approximately 120 °C.
- Flash point: 25 °C (ISO 2719).
- Density: 0.98 g/cm³ at 20 °C.
- Water solubility: Insoluble; immiscible with water.
- Lower explosion limit: 1.0 % (V).
- Upper explosion limit: 10.0 % (V).
- Ignition temperature: > 400 °C.
- Viscosity (flow time): 34 s, DIN 53211, 4 mm cup.
- VOC content (Directive 1999/13/EC): 56 %, 553 g/l (excluding water).
Classification and hazards (converter C6402)
- Flammable liquids, Category 3: H226 – Flammable liquid and vapour.
- Skin sensitization, Category 1: H317 – May cause an allergic skin reaction.
- STOT single exposure, Category 3 (central nervous system): H336 – May cause drowsiness or dizziness.
- Supplemental statement: EUH066 – Repeated exposure may cause skin dryness or cracking.
- Additional labelling: EUH204 – Contains isocyanates. May produce an allergic reaction.
System mixing ratios with ALEXSEAL Interior Topcoat 578
- Spray application:
- 4 parts by volume ALEXSEAL Interior Topcoat 578 (Base Color).
- 1 part by volume C6402 ALEXSEAL Interior Topcoat Converter.
- 20–30 % by volume ALEXSEAL Interior Topcoat Reducer (R6062 or R6068 Slow).
- Example: 4 : 1 : 1 to 1.5 (20–30 % reduction with reducer).
- 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 % by volume ALEXSEAL Interior Topcoat Reducer (R6062 or R6068 Slow).
- Example: 4 : 1 : 0.5 to 0.75 (10–15 % reduction).
- Important: Mixed material must be filtered before application.
Recommended application parameters for the mixed system
- Viscosity (mixed product): Zahn #2: approx. 15–18 s; DIN 4 cup (4 mm): approx. 12–18 s.
- Gravity spray gun nozzle: 1.2–1.6 mm (conventional and HVLP).
- Pressure pot fluid nozzle: 1.0–1.3 mm (conventional and HVLP).
- 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).
Film build and drying (mixed system)
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 film build by spray: 2 coats totaling 180–220 µm (7–9 mils) WFT, or 60–70 µm (2.5–3 mils) DFT.
Brush and roller application
- Apply 2–3 coats to a wet film thickness of 25–37.5 µm per coat.
- Each coat should dry to tape-dry stage in 12–24 hours.
- DFT for 2 coats: 25–37.5 µm.
- DFT for 3 coats: 35–45 µm.
Pot life and drying times (mixed product)
Optimal application environment: 15–30 °C (60–85 °F), 40–80 % relative humidity; minimum application temperature 3 °C (5.4 °F) above dew point.
- Pot life (approx.):
- 18 h at 15 °C (60 °F).
- 12 h at 20 °C (68 °F).
- 9 h at 25 °C (77 °F).
- 6 h at 30 °C (85 °F).
- Dust free: 40–60 min (15 °C); 30–45 min (20 °C); 20–30 min (25 °C); 15–20 min (30 °C).
- Tape dry: 32 h (15 °C); 24 h (20 °C); 16 h (25 °C); 12 h (30 °C).
- Fully cured: 14 days (15 °C); 7 days (20 °C); 5 days (25 °C); 3 days (30 °C).
- Recoat with ALEXSEAL Interior Topcoat 578 (spray application): 40–60 min (15 °C); 30–45 min (20 °C); 20–30 min (25 °C); 15–20 min (30 °C); maximum 4 h.
- Overcoat with another product (sanding required): 24 h (15–20 °C); 18 h (25 °C); 12 h (30 °C).
Storage conditions for the converter
- Storage temperature: 5–35 °C.
- Keep container tightly closed and upright; avoid heating and direct sunlight.
- Always keep in containers of the same material as supplied.
- Do not keep containers sealed completely: reaction with atmospheric humidity can form CO₂ and lead to pressure build-up.
- Keep away from oxidizing agents and strongly acidic or alkaline materials.
Applications and use cases
- Yacht interiors: When used with ALEXSEAL Interior Topcoat 578, the converter helps create decorative and protective finishes on walls, ceilings, panels and other interior surfaces.
- Engine room parts: Suitable for interior components in engine rooms where resistance to oils, cooling agents and cleaning chemicals is required.
- Industrial serial painting: Designed for professional coating operations that require consistent pot life, controllable film build and durable performance.
FAQ – ALEXSEAL Interior Topcoat 578 Converter
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What is the role of C6402 Interior Topcoat 578 Converter?
It is the polyisocyanate hardener component of the ALEXSEAL Interior Topcoat 578 system. Mixed with the base color and reducer, it cures the coating to a tough, chemical- and abrasion-resistant polyurethane film.
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What is the correct mixing ratio with the base topcoat?
For both spray and brush/roller, use 4 parts Interior Topcoat 578 base color to 1 part C6402 converter. Then add 20–30 % reducer for spray application or 10–15 % reducer for brush and roller.
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How long is the pot life after mixing?
Pot life is approximately 18 h at 15 °C, 12 h at 20 °C, 9 h at 25 °C and 6 h at 30 °C. Higher temperatures shorten pot life.
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Can the system be used outdoors?
The coating system is recommended for interior applications only. Outdoors or under extreme weather, uncleaned surfaces may show slight gloss and color changes due to UV exposure, although the protective properties of the film remain.
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Do I need a primer before applying the Interior Topcoat 578 system?
The topcoat has good adhesion and can be applied directly on appropriately cleaned and pretreated substrates, including aluminum. For optimum corrosion protection, the use of ALEXSEAL Interior Primer 178 is recommended.
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What film thickness should I aim for?
For spray application, target 50–75 µm WFT per coat, giving 30–50 µm DFT after two coats. Maximum recommended by spray is 60–70 µm DFT. For brush/roller, 2–3 coats at 25–37.5 µm WFT per coat give 25–37.5 µm DFT (two coats) or 35–45 µm DFT (three coats).
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What are the recommended application conditions?
Apply between 15–30 °C and 40–80 % relative humidity. During drying, keep the temperature at or above 15 °C, ideally around 25 °C. The surface temperature should be at least 3 °C above the dew point.
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How should I store the converter?
Store between 5–35 °C in tightly closed, upright containers away from heat, ignition sources, oxidizing agents and strong acids or bases. Avoid direct sunlight and prevent exposure to moisture.
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What are the main hazards of the converter?
It is a flammable liquid and vapour and may cause drowsiness or dizziness. It can cause an allergic skin reaction and may cause skin dryness or cracking with repeated exposure. It contains isocyanates, which may produce an allergic reaction.
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Is the converter suitable for DIY use?
No. Both the converter and the Interior Topcoat 578 system are designated for professional and industrial use only.
Section 14 – Transport information (converter C6402)
The following information applies to the transport of ALEXSEAL C6402 Interior Coating Converter as supplied.
ADR (road / rail)
- UN number: 1263
- Proper shipping name: PAINT RELATED MATERIAL
- Class: 3
- Packing group: III
- Classification code: F1
- Hazard identification number: 30
- Labels: 3
- Tunnel restriction code: D/E
- Special provision: 640E
- Environmentally hazardous: No
IMDG (sea)
- UN number: 1263
- Proper shipping name: PAINT RELATED MATERIAL
- Class: 3
- Packing group: III
- Labels: 3
- EmS: F-E, S-E
- Marine pollutant: No
IATA (air)
- UN number: 1263
- Proper shipping name: PAINT RELATED MATERIAL
- Class: 3
- Packing group: III
- Labels: 3
- Packing instruction (cargo aircraft): 366
- Packing instruction (passenger aircraft): 355
- Packing instruction (passenger aircraft, limited quantities): Y344
- Environmentally hazardous: No
Additional transport guidance
- If transported within the user’s premises, always move in closed, upright and secure containers.
- Ensure personnel handling containers are aware of emergency procedures in case of incident or spillage.
- For personal protection during transport handling, refer to the individual protection measures described in Section 8 below.
Section 8 – Individual protection measures (converter C6402)
Exposure controls
- Provide adequate local exhaust ventilation and general extraction to keep concentrations below occupational exposure limits.
- If ventilation is insufficient, suitable respiratory protection must be used.
Personal protective equipment
- Eye protection: Safety goggles to protect against solvent splashes.
- Hand protection:
- Use chemical-resistant protective gloves tested in compliance with EN 374.
- Recommended for short-term contact (splash protection): nitrile rubber or neoprene.
- Minimum material thickness: > 0.4 mm.
- Breakthrough time: > 480 minutes.
- Inspect gloves for suitability and replace immediately if damaged or worn.
- Skin and body protection: Wear antistatic clothing made of natural fibers or high-temperature-resistant synthetic fibers. Wash all exposed skin after contact. Prevent prolonged use of gloves by designing work steps accordingly.
- Respiratory protection:
- During spraying: use air-fed respirator.
- For other operations in well-ventilated areas: a combination charcoal and particulate filter mask may be used instead of air-fed respirators.
- General protective measures:
- Persons with a history of asthma, allergies or chronic/recurrent respiratory disease should not work with this preparation.
- Do not eat, drink or smoke during use.
- Avoid contact with skin, eyes and clothing.
- Avoid inhalation of sanding dust, particulates and spray mist.
Environmental exposure controls
- Do not allow the product to enter drains, lakes, rivers or sewage systems.
- If contamination occurs, notify the relevant authorities according to local regulations.
*Contenido generado por IA
