Polyurethane Powder Coatings: A Review of Composition and Characterization

Abstract

Powder coatings have gained a lot of attention since the 1960s and the 1970s (implementation of polyurethanes into the market) because of the environmental and ecological concerns. Over the decades, there have been several publications relating the manufacturing and development of powder coatings as an alternative for liquid/solvent or water-based organic coatings. In general, powder coatings can be divided into two main groups based on the properties of the resin being used, thermoplastic and thermoset powder coating systems. Among thermoset powder coatings, polyurethane powder coatings have outstanding properties such as weather stability and are the best choice for exterior applications comparing overall properties. This paper reviews the most recent advances in the field of powder coating by focusing on polyurethane powder coating as a group of thermoset powder coatings. It also considers the industrial problems engaged in this field, such as emission of the blocking agents, the low reactivity of uretdione systems, and high curing temperature and their solutions. Finally, it also suggests the future potential investigation of polyurethane powder coating compositions and improvements.

Synthesis and characteristics of nonisocyanate polyurethane composed of bio‐based dimer diamine for supercritical CO2 foaming applications

“…Polyurethanes (PU) are extensively used in numerous fields owing to their high elasticity, chemical resistance, and plasticity properties. [1][2][3][4][5][6][7][8][9] The traditional methods of PU synthesis substantially use isocyanates for polymerization. The electrophilic capabilities of the isocyanates contribute to significant reactivities to various nucleophiles of alcohols, amines, and water; however, the precursor is phosgene, which is highly toxic.…”

“…Polyurethanes (PU) are extensively used in numerous fields owing to their high elasticity, chemical resistance, and plasticity properties 1–9 . The traditional methods of PU synthesis substantially use isocyanates for polymerization.…”

Synthesis, Monomer Removal, Modification, and Coating Performances of Biobased Pentamethylene Diisocyanate Isocyanurate Trimers

“…Polyurethane (PU) coatings, common for industrial applications, are divided into two-component (2K-PU) and one-component (1K-PU) coatings. − 2K-PU coatings with superior performances, like low film-forming temperature, strong adhesion, good abrasion resistance, high hardness, chemical resistance, and good weather resistance, are widely used in industrial protection, wood furniture, automotive and marine industries, and high-speed train coatings. − Waterborne 2K-PU coatings, a class of environmentally friendly coating, consist of a waterborne polyol containing −OH groups and a low-viscosity polyisocyanate curing agent containing −NCO groups. These coatings combine the superior performances of solvent-borne 2K-PU coatings and the low volatile organic compound (VOC) content of waterborne coatings, and have thus received increasing research attention. − …”

Glutathione reactivity with aliphatic polyisocyanates

“…The most commonly used formulations (Fig 1 ) are "trimers" of HDI, the isocyanurate and the biuret (prepared with limited addition of water), with slightly different properties that impart distinct advantages/disadvantages in the final product [12,15]. A "dimeric" form of HDI containing an internally blocked uretdione moiety is also employed for specialty applications and has reduced viscosity making it useful as a "thinning" agent suitable for mixing with other isocyanates [12,28].…”