Clear High-Gloss 2K Polyurethane Topcoat for Automotive Utilizing

This is a high-performance, water-based two-component polyurethane (PU) clear coat designed for automotive applications. The formulation is based on Bayhydrol U XP 2766 and Bayhydur XP 2655, providing a high-gloss, durable finish with excellent weather resistance and low VOC emissions.

Components and Formulation:

Component 1:

• Bayhydrol U XP 2766 (Covestro): Main resin providing the film-forming base.
• Borchi® Gol LA 2 (Milliken): Additive for improved flow and leveling.
• Borchi® Gol LA 50 (Milliken): Additive to enhance surface smoothness.
• Borchi® Gol LA 200 (Milliken): Additive for better slip and deaeration.
• Water: Used for thinning and adjusting viscosity.

Component 2:

• Bayhydur XP 2655 (Covestro): Polyisocyanate hardener that reacts with the resin to form a tough, crosslinked film.
• Tinuvin 384-2 (Ciba Specialty Chemicals): UV stabilizer for improved weather resistance.
• Tinuvin 292 (Ciba Specialty Chemicals): UV absorber to enhance durability.
• Butoxyl (Celanese): Solvent to aid in the mixing and application process.

Mixing and Application:

Mixing Instructions:

1. Component 1:
   • Add Bayhydrol U XP 2766 to the mixing vessel.
   • Stir in Borchi® Gol LA 2, Borchi® Gol LA 50, and Borchi® Gol LA 200 for 5 minutes at 2000 rpm.
   • Gradually add water while stirring at approximately 2000 rpm.
   • Allow the mixture to deaerate for one day.
2. Component 2:
   • Stir in Bayhydur XP 2655, Tinuvin 384-2, Tinuvin 292, and Butoxyl at approximately 2000 rpm.

Application Method:

• Mix Component 1 and Component 2 for 2 minutes at 1000 rpm.
• Add water to adjust the application viscosity.
• Spray using appropriate equipment.

Technical Data:

Mixing Ratio:

• NCO:OH ratio of 1.5:1

Viscosity and Solids:

• Solid Content on Application: Approximately 45%
• Spray Viscosity (DIN 53211-cup 4 mm at 23 °C): 25 seconds with approximately 10% water
• VOC Content: 164 g/l (calculated according to Directive 1999/13/EC)

Gloss and Drying Time:

• Gloss (20° / 60° on ABS - Bayfoil): 92 / 95
• Drying Time (DIN 53150 at Room Temperature):
  • TG 1: 0.5 hours
  • TG 2: 3 hours
  • TG 3: 4 hours

Hardness:

• Film Hardness (Pendulum Hardness Tester-König, DIN EN ISO 1522): 219 seconds after 30 minutes at 80 °C

Suppliers:

• Covestro: Supplier of Bayhydrol U XP 2766 and Bayhydur XP 2655.
• Milliken: Supplier of Borchi® Gol LA 2, Borchi® Gol LA 50, and Borchi® Gol LA 200.
• Ciba Specialty Chemicals: Supplier of Tinuvin 384-2 and Tinuvin 292.
• Celanese: Supplier of Butoxyl.

Notes:

• This formulation is provided for reference and guidance. Users should test and ensure its suitability for their specific applications.
• All sales are subject to the supplier's standard terms and conditions.

This aqueous two-pack PU clear coat formulation is designed for automotive applications requiring high gloss, durability, excellent weather resistance, and low VOC emissions, ensuring a superior protective finish.