Clear High Gloss 2K Polyurethane Topcoat for Wood & Furniture

Starting point formulation for a high-performance, waterborne polyurethane topcoat designed for wood flooring and cabinetry. This formulation emphasizes low VOC content, high hardness, high gloss, robust chemical resistance, and excellent abrasion resistance. It is tailored to enable superior performance properties in coatings for interior applications. Here are the detailed aspects of this formulation:

Purpose:

• Type of Coating: High gloss, low VOC, waterborne polyurethane topcoat.
• Application: Wood flooring and cabinetry.

Key Benefits:

• Low VOC: Environmentally friendly.
• NMP Free: Free from N-Methyl-2-pyrrolidone, a solvent often restricted due to health concerns.
• High Hardness: Durable surface.
• High Gloss: Attractive finish.
• Robust Chemical Resistance: Withstands exposure to various chemicals.
• Improved Solvent Rub Resistance: Enhanced durability against solvents.
• Excellent Abrasion Resistance: Long-lasting finish under physical wear.

Formulation Ingredients:

Base Components:

• UROTUF® L63-W-38: Resin supplied by Polynt-Reichhold.
• Ethyl Carbitol: Coalescent from Sigma-Aldrich.

Performance Additives:

• Borchi® Gel 0625: VOC-free and APEO-free medium shear range HEUR thickener from Milliken.
• Borchi® Gol LA 200: VOC-free, 100% active air release agent with flow and leveling properties from Milliken.
• Borchi® Gol LA 50: Substrate wetting additive with flow and leveling properties from Milliken.
• Surfynol 104E: Surfactant from Evonik.

Solvents:

• Water: Used as a solvent.
• Additional Ethyl Carbitol: Used in a secondary mix.

Mixing Instructions:

1. Mix the Base Components: Combine UROTUF® L63-W-38 and Ethyl Carbitol.
2. Prepare Additives Mixture: Mix Borchi® Gel 0625, Ethyl Carbitol, and Water before adding to the base mixture.
3. Add Remaining Additives and Solvents: Incorporate Borchi® Gol LA 200, Borchi® Gol LA 50, Surfynol 104E, and additional Water.

Application Properties:

• Solvent Rub Performance: Excellent, withstanding 200 solvent double rubs.
• Abrasion Resistance: Outstanding, tested using a Taber Abraser with a CS-17 wheel, 1 kg load, over 1000 cycles.
• Chemical Resistance: Tested against various chemicals with ratings indicating levels of resistance.

Film Performance:

• Dry Time:
  • Set to Touch: 13 minutes.
  • Tack Free: 20 minutes.
  • Through Dry: 40 minutes.
• Gloss: High gloss with 60° gloss at 84 and 20° gloss at 94.
• König Hardness: 146.5 seconds.
• Taber Abrasion: 16.1 mg loss.
• Color Metrics: L* = 92.86, a* = -0.59, b* = 4.73.

Chemical Resistance Ratings (0-5, with 5 being no effect):

• Acetic Acid, Ammonia, Olive Oil, and various household substances: High resistance (4-5).
• Black Marker, Bug Spray, and certain solvents: Lower resistance (1-3).

Suppliers:

• Covestro: Desmodur N 75.
• Hoffmann Mineral: Silithin V 88.
• Eastman Chemical: CAB 381-2.
• Milliken: Borchi® additives.
• Polynt-Reichhold: UROTUF® L63-W-38.
• Sigma-Aldrich: Ethyl Carbitol.
• Evonik: Surfynol 104E.