What is ALEXSEAL HS Base Coat Activator Medium R5541 and why choose it
ALEXSEAL HS Base Coat Activator Medium R5541 is a halogen-free organic solvent blend specifically formulated as the standard activator for the ALEXSEAL HS Base Coat system. It is designed for professional industrial serial painting and marine applications where fast-drying, high-solid polyurethane base coats are required. When used in the recommended mixing ratio with ALEXSEAL HS Base Coat and Converter, R5541 helps to achieve excellent hiding power, strong chemical and mechanical resistance and a highly glossy, color-stable finish on yacht surfaces not subject to permanent water immersion.
This activator offers a controlled medium drying speed that supports efficient spray application, reliable curing and high-quality multi-color schemes, particularly when the HS Base Coat will be overcoated with ALEXSEAL clear coats such as ALEXSEAL Topcoat 501 Clear Coat.
Main features
- Dedicated activator for ALEXSEAL HS Base Coat high-solid two-component polyurethane base coats.
- Medium drying speed, balanced for efficient spraying and proper film formation.
- Supports fast-drying base coat applications with excellent hiding power and gloss when clear coated.
- Formulated as a mixture of halogen-free organic solvents.
- Optimized for professional industrial serial painting and yacht finishing.
- Used in a fixed 3:1:1 mixing ratio (HS Base Coat : Converter : Activator).
- Supplied in convenient 1 QT packaging for controlled mixing on site.
Technical specifications
Product identification
- Commercial product name: ALEXSEAL R5541-HS Base Activator Medium
- Brand: ALEXSEAL (Mankiewicz)
- Intended use: Industrial serial painting; activator for ALEXSEAL HS Base Coat
- Chemical nature: Mixture of organic solvents, halogen-free
Packaging and trade name
- R5541 ALEXSEAL HS Base Activator Medium: 1 QT
Key physical and chemical data
- Physical state: Liquid (20 °C, 1,013 hPa)
- Colour: According to product name
- Odour: Characteristic
- Boiling range: Approx. 120 °C
- Flash point: 25 °C (ISO 13736)
- Upper explosion limit: 10.0 % (V)
- Lower explosion limit: 1.0 % (V)
- Auto-ignition temperature: > 400 °C
- pH (10 % solution, 20 °C): 3 – 4
- Kinematic viscosity: > 6 mm²/s
- Flow time: 12 s (DIN 53211, 4 mm); < 10 s (ISO 2431, 6 mm)
- Water solubility: Insoluble; immiscible with water
- Vapour pressure: Approx. 100 hPa (50 °C)
- Density: Approx. 0.9 g/cm³ (20 °C)
- VOC content: 99.51 %, approx. 900 g/l (Directive 2010/75/EU)
Classification and hazards (EU CLP)
- Flammable liquids, Category 3 (H226): Flammable liquid and vapour.
- Acute toxicity, Category 4 (H302, H332): Harmful if swallowed or if inhaled.
- Eye irritation, Category 2 (H319): Causes serious eye irritation.
- Reproductive toxicity, Category 1B (H360FD): May damage fertility. May damage the unborn child.
- Specific target organ toxicity – single exposure, Category 3 (H336): May cause drowsiness or dizziness.
- Long-term aquatic hazard, Category 3 (H412): Harmful to aquatic life with long lasting effects.
- Signal word: Danger
- Additional labelling: Restricted to professional users.
Recommended mixing ratio in the HS Base Coat system
- 3 parts by volume ALEXSEAL HS Base Coat (Hxxxx)
- 1 part by volume ALEXSEAL HS Base Coat Converter (C5047)
- 1 part by volume ALEXSEAL HS Base Activator Medium (R5541)
- Example ratio: 3:1:1
- The quantity of ALEXSEAL HS Activator (activated reducer) is fixed and cannot be changed.
- Mixed material must be filtered through a suitable paint filter before application.
Applications and use cases
- Yacht finishing: Activator for ALEXSEAL HS Base Coat on interior and exterior yacht areas that are not permanently immersed in water, before sealing with ALEXSEAL Clear Coat.
- Multi-color schemes: Supports fast-drying HS Base Coat applications used to realize multi-color designs on yachts; the base coat is tape-dry after approximately 4 hours when used with the system.
- Industrial serial painting: Suitable for professional spray operations where consistent drying and curing of HS Base Coat are required.
- Use with ALEXSEAL Topcoat 501 Clear Coat: When ALEXSEAL Topcoat 501 Clear Coat is applied over HS Base Coat, the HS Base Coat must be activated specifically with R5541 ALEXSEAL HS Base Activator Medium (R5521 Slow is not to be used for this purpose).
FAQ – HS Base Coat Activator Medium R5541
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Can HS Base Coat Activator Medium be used with any paint system?
No. ALEXSEAL R5541 HS Base Activator Medium is formulated for use within the ALEXSEAL HS Base Coat system. For other systems, Consultar ficha técnica del fabricante.
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What is the correct mixing ratio with ALEXSEAL HS Base Coat?
The recommended mixing ratio is 3:1:1 by volume – three parts HS Base Coat, one part C5047 HS Base Coat Converter and one part R5541 HS Base Activator Medium.
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Can the amount of activator be adjusted to change the drying speed?
No. The amount of ALEXSEAL HS Activator in the mixture is fixed and must not be altered.
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Is R5541 suitable for use when overcoating with ALEXSEAL Topcoat 501 Clear Coat?
Yes. When ALEXSEAL Topcoat 501 Clear Coat is applied on top of HS Base Coat, R5541 HS Base Activator Medium must be used during the HS Base Coat application.
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Who is allowed to use HS Base Coat Activator Medium?
The product is restricted to professional users and should only be handled by trained personnel following applicable safety and health regulations.
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Is the product water-soluble?
No. ALEXSEAL R5541 HS Base Activator Medium is insoluble and immiscible in water.
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What should be done in case of accidental spillage?
Contain and collect the spill with non-combustible absorbent materials (such as sand, earth, vermiculite or diatomaceous earth) and dispose of according to local regulations. Prevent the product from entering drains or watercourses.
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How should contaminated packaging be handled?
Contaminated packaging should be emptied as far as possible and may be reused after proper cleaning. Packaging that cannot be cleaned must be disposed of in agreement with the regional waste disposal company.
Section 14 – Transport information
- UN number / ID number: UN 1263
- UN proper shipping name (ADR / IMDG / IATA): PAINT RELATED MATERIAL
ADR (Road transport)
- Class: 3
- Packing group: III
- Classification code: F1
- Hazard identification number: 30
- Labels: 3
- Tunnel restriction code: (D/E)
- Special remark: If transported within the user’s premises, always transport in closed, upright and secure containers. Ensure personnel handling the containers are aware of emergency procedures in case of incident or spillage.
- Environmentally hazardous: No
IMDG (Sea transport)
- Class: 3
- Packing group: III
- Labels: 3
- EmS code: F-E, S-E
- Marine pollutant: No
IATA (Air transport)
- Class: 3
- Packing group: III
- Packing instruction (cargo aircraft): 366
- Packing instruction (passenger aircraft): 355
- Packing instruction (limited quantities): Y344
- Labels: Flammable Liquids
The transport classifications above are based on the properties of the unpackaged material as described in the Safety Data Sheet. Actual classification can vary depending on packaging, mode of transport and regional regulations.
Section 8 – Personal protective measures
Exposure control and general safety
- Ensure adequate ventilation through local exhaust and general extraction. If solvent vapour concentrations exceed occupational exposure limits, appropriate respiratory protection must be used.
- Smoking, eating and drinking are prohibited in the application area.
- Avoid inhalation of vapours, spray mist and sanding dust from coatings containing this product.
Individual protective equipment
- Eye/face protection: Wear safety goggles to protect against solvent splashes.
- Hand protection: Use chemical-resistant protective gloves tested according to EN 374. For short-term contact and splash protection, recommended materials are nitrile rubber or neoprene with a minimum thickness > 0.4 mm and breakthrough time > 480 minutes. Follow glove manufacturer instructions and replace gloves immediately if damaged or worn.
- Skin and body protection: Wear suitable protective clothing, selected according to the likelihood of explosive atmospheres and solvent exposure.
- Respiratory protection: If solvent concentrations exceed air limit values, wear an approved breathing apparatus, such as a half-mask with appropriate cartridge or an air-fed respirator. When working inside spray booths where ventilation may be insufficient, use a compressed air-fed respirator during spraying until vapour and particulate concentrations fall below exposure limits.
- Hygiene measures: Do not eat or drink while working. Avoid contact with skin, eyes and clothing. Wash contaminated skin immediately and use preventive skin protection creams where appropriate.
*Contenido generado por IA
