Wood, metal, plastic and other substrates have to stand up to any number of damaging forces—the environment, human and pet traffic (in the case of wood floors), chemical exposure (in the case of industrial metals), to name a few. Apart from the inherent durability properties of the substrate, coatings are the first line of defense for toughness, durability, chemical resistance and high temperature stability in most applications.
The coating used is a big part of the performance equation, and there are many choices depending on the type of substrate. Water-based polyurethane. Oil-based polyurethane. Oil sealer. Hard-wax oil. Acid-cured finishes. Epoxy. Moisture cure urethane.
Polyurethane is one of the more popular choices, which begs the question, what’s the best polyurethane for the job? It depends on the desired qualities, but the best polyurethane should have multiple properties:
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Strength and longevity with high levels of hardness and toughness to look better and last longer
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Chemical resistance or durability to hold up to environmental factors
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Excellent weathering and thermal resistance
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The least toxic
The end-use performance of water-borne polyurethane dispersion (PUD) coatings is mainly derived from the large segments of polyols used in their production. The majority of PUD offerings in the marketplace are made of common polyester, polyether or polycarbonate polyols. Each of these classes of polyols offers some performance advantages but they fall short on other properties (i.e., poor hydrolysis resistance, UV resistance, cost).
Polyamide polyurethane is the relative new kid on the block in coatings. Incorporation of polyamide into urethane coating systems has been tried in the past with very limited success. Due to strong intermolecular hydrogen bonding, polyamide oligomers are usually very viscous and hard to handle for further modification. Common polyamide segments made of diacids and diamines are not suitable soft segments for the synthesis of multi-segment polyurethanes. To overcome this challenge, a series of telechelic N-alkylated polyamide oligomers was developed, which do form nice soft segments in polyurethanes.
Copolymer Dispersions Unlock New Advantages
Incorporating polyamide segments in the backbone of the resins led to the creation of new water-borne polyurethane/urea copolymer dispersions. These new segmented copolymers exhibited outstanding properties for coating applications, particularly in heat-resistance, hydrolytic stability, chemical resistance, hardness development and adhesion to a variety of substrates.
Where other PUDs falls short in at least one area, polyamide polyurethane technology offers new levels of performance and capability. Lubrizol developed and brought this exclusive technology to market under the brand name Aptalon™ as a self-crosslinking polyurethane technology that gives formulators new choices for addressing industry challenges for durable water-borne wood, metal and plastic coatings.
Coating formulations made with Aptalon polyamide polyurethane technology are designed to deliver very high performance properties in a 1K system and provide hydrolysis resistance, hardness, and chemical resistance that outperforms other water-borne polyurethane chemistries and matches or exceeds many 2K water-borne finishes without the need for external cross-linkers. Formulators can achieve outstanding performance from a water-borne polyurethane for many applications, from high-performance wood coating and flooring for residential or commercial use, athletic wood floors, self-matting wood coatings, pigmented metal and much more.
Contact your Lubrizol account manager or visit www.lubrizol.com/aptalon to learn more about achieving new levels of resin performance with Aptalon polyamide polyurethane technology, which can be tailored to achieve specific levels of hardness, gloss, elasticity, and VOC.
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