Two-pack PU wood primer, fast drying and sandable

The document outlines the formulation for a two-pack polyurethane (PU) wood primer designed for wood and furniture coatings. This primer is fast-drying and sandable, making it suitable for use in the initial preparation of wood surfaces before applying the final topcoat. Here are the detailed aspects of this formulation:

Purpose:

• Type of Coating: Two-pack PU wood primer.
• Application: Fast drying, sandable.
• Primary Uses: Wood and furniture coatings.

Components:

Component 1:

• Setalux D RD 181 MPA: Main resin component.
• Methoxy propyl acetate / Xylene (1:1): Solvent mixture.
• Silithin V 88: Additive for enhanced properties. Dispersion for 10 minutes at about 2000 rpm.
• Setalux D A 450 BA/X: Secondary resin component.
• CAB 381-2 (25% in butyl acetate): Cellulose acetate butyrate, used as a film former.
• Borchi® Gol LA 200: Additive for improved performance.
• Butyl acetate: Solvent.
• Xylene: Solvent.

Component 2:

• Desmodur N 75 (75% in methoxy propyl acetate): Polyisocyanate curing agent.

Mixing Ratio:

• Component 1: Component 2 = 10:1 by weight.

Application Properties:

• Binder Content: 23.5%.
• Solids Content:
  • Component 1: 25.7%.
  • On application: 27.7%.
• Thinning for Spray Viscosity: Use a mixture of xylene and butyl acetate in a 1:1 ratio.
• Spray Viscosity: Approximately 21 seconds (DIN 53211-cup 4 mm, at 23°C).
• Pot Life: More than 8 hours (DIN-cup 4 mm, at 23°C).
• Drying Time: Sand free in 6 minutes (DIN 53150, at 23°C).

Application Method:

• HVLP-gun spraying: Recommended application method for optimal results.

Suppliers:

• Covestro: Supplier of Desmodur N 75.
• Hoffmann Mineral: Supplier of Silithin V 88.
• Eastman Chemical: Supplier of CAB 381-2.
• Milliken: Supplier of Borchi® Gol LA 200.
• Allnex: Supplier of Setalux D RD 181 MPA and Setalux D A 450 BA/X.

Notes:

• This formulation serves as a starting point and should be tested and adjusted according to specific needs and conditions.
• The information provided is in good faith but without warranty. Each customer must verify suitability for their own use.
• All sales are subject to standard terms of sale.

This primer is formulated to provide a solid foundation for subsequent coatings, ensuring good adhesion, fast drying, and easy sandability, making it ideal for professional wood finishing processes.