Aromatic Polyisocyanate Hardeners for 2K PU Wood Coatings

Kabasph® aromatic polyisocyanate hardeners are a comprehensive range of TDI-based and TDI/HDI hybrid crosslinkers engineered for two-component polyurethane (2K PU) wood and furniture coating formulations. This product family includes five distinct grades—KBS-75, KBS-50BA, KBS-960E, KBS-60H, and KBS-60HL—each tailored to meet specific performance requirements in terms of drying speed, film hardness, gloss control, and lightfastness.

Key Advantages and Benefits

l Fast Drying and Early Sandability

The TDI trimer and TDI adduct chemistry delivers exceptionally rapid initial drying and early sandability, enabling shorter cycle times in industrial wood coating production lines. Formulations using these hardeners exhibit quick dry-to-handle properties and minimal tendency to run from sharp edges, allowing for efficient spray or curtain coating application. This fast-drying behavior is particularly valuable for high-throughput furniture manufacturing, where production speed directly impacts output capacity and cost efficiency.

l Low Free Monomer Content (≤0.5%)

All five product grades maintain free TDI or TDI+HDI monomer content at or below 0.5%, meeting stricter handling and safety requirements compared to conventional aromatic polyisocyanate hardeners. Low free monomer content reduces occupational exposure concerns during coating application and supports compliance with increasingly stringent workplace safety regulations. This makes these products suitable for formulators seeking to balance performance with responsible chemical management.

l Superior Hardness and Mechanical Strength

The isocyanurate-type aromatic polyisocyanate structure formed through TDI trimerization enables dense crosslinking with hydroxyl-functional resins, polyols, and other active-hydrogen-containing systems. This results in coatings with high film hardness, excellent abrasion resistance, and strong adhesion to wood substrates. KBS-75's TDI adduct chemistry additionally contributes flexibility to the cured film, making it suitable for applications requiring a balance between hardness and impact resistance.

l High Solids and Low Viscosity Options

KBS-960E offers an exceptionally low viscosity of 125±50 cps at 25°C, enabling the formulation of clear and colored coatings with high solids contents that can be applied quickly with minimal coats. KBS-75 provides 75±2% solids with a moderate viscosity of 1500±500 cps, suitable for high-gloss topcoat applications. This range of solids-viscosity profiles allows formulators to optimize coating systems for specific application methods, including spray, curtain coating, and roll coating.

l Non-Yellowing Performance (TDI/HDI Hybrid Grades)

KBS-60H and KBS-60HL combine TDI and HDI chemistry to deliver improved non-yellowing performance compared to pure TDI-based hardeners. While standard TDI trimers are generally more cost-effective and reactive but weaker in non-yellowing performance and outdoor weatherability, the TDI/HDI hybrid approach provides a practical balance for applications requiring better color stability without the full cost premium of pure aliphatic HDI systems. KBS-60HL is specifically designed for high-gloss finish applications with low free monomer content and light color.

l Excellent Compatibility and Formulation Flexibility

These aromatic polyisocyanate hardeners demonstrate good compatibility with a wide range of co-reactants, including polyester polyols, acrylic polyols, alkyd resins, and polyether polyols. KBS-960E is compatible with conventional acrylic resins and nitrocellulose-containing resins. KBS-75 is compatible with many polyesters, polyethers, and polyacrylates, as well as with other isocyanate grades. This compatibility supports formulation flexibility across different coating systems and performance targets.

Application Areas

l Interior Wood and Furniture Coatings

l Matte and Semi-Matte Topcoats

l High-Gloss Clear and Pigmented Coatings

l Wood Sealers and Primers

l TDI/HDI Hybrid Applications

These aromatic polyisocyanate hardeners are supplied as upstream curing-agent and crosslinker raw materials for coating formulators. Technical data sheets, samples, and formulation-specific grade-selection support are available upon request.