Coating Additives

Coating Additives

Introduction

Amines and organometallic catalysts are commonly used as accelerators in the polyol/isocyanate reaction to produce polyurethanes. When formulating a polyurethane coating, it has been found that both performance and properties can be affected by the choice of catalyst.

Amine catalysts are typically used in foam applications. Their catalytic activity accelerates the reaction of aromatic isocyanates with water and alcohols, releasing carbon dioxide. Use of amines in coating applications, however, is generally not acceptable because of their negative effect on film properties, especially yellowing.

The current K-KAT catalyst product line shown (Table 1) is based on organometallic chemistry. These products present an alternative to conventional tin catalysts and can provide unique variations in cure response, storage stability and contributions to film performance.

K-KAT 348 is a metal carboxylate which can be used in blocked isocyanate and two component urethane systems offering:

	Excellent exterior durability
	Non-yellowing characteristics
	Excellent gloss retention

K-KAT XC-4205 is a liquid metal complex which is an effective catalyst for two component urethane coatings providing:

	Fast tack free time
	Excellent viscosity stability/pot life
	Excellent exterior durability
	Use levels at low metal concentrations

K-KAT XC-5218 is an effective catalyst for both baked and ambient cured 2K urethane systems offering:

	Synergy with pot life extenders such as 2, 4 - Pentanedione
	Excellent exterior durability

K-KAT XC-6212 is recommended for use in two component plural gun or in-line mixing applications providing:

	Rapid cure response and fast tack free time
	Excellent low temperature cure response
	High selectivity for -NCO/OH reaction over - NCO/water reaction
	Reduced interactions with treated TiO2