Waterborne polyurethane, abbreviated as WPU, is a polymer compound based on polyurethane. It is typically defined as a high molecular weight compound with repeating urethane functional groups (NHCOO) on the main chain of the polymer.
The structure of waterborne polyurethane is represented as CO—NH—R—NH—CO—O—R—O. It is commonly synthesized through the step-growth polymerization reaction of diisocyanates or polyisocyanates with compounds containing two or more active hydrogen groups. Besides urethane groups, other functional groups such as urea and biuret can also be generated during the synthesis.
Therefore, in general, waterborne polyurethane is the addition product of isocyanates. Depending on the number of functional groups in the reactants, waterborne polyurethane can be synthesized into linear or branched structures, resulting in different properties and applications of the obtained waterborne polyurethane emulsions.
Characteristics of Waterborne Polyurethane:
1. High elasticity and cost-effectiveness.
2. Easy to use and modify.
3. Safe, non-toxic, non-flammable, with strong adhesion.
4. Resistant to high and low temperatures, and easy to store.
Applications of Waterborne Polyurethane:
1. Textile industry: Waterborne polyurethane is used as a coating to improve fabric performance, such as dye depth, colorfastness, abrasion resistance, wrinkle resistance, resilience, water resistance, heat resistance, and washability.
2. Automotive industry: Waterborne polyurethane coatings are widely used in automotive body parts, interior and exterior components, coatings for various plastic parts, automotive paints for surface finishing, and touch-up paints. They significantly reduce VOC emissions.
3. Wood industry: Waterborne polyurethane coatings are commonly used for wood finishes. They provide excellent flexibility, wear resistance, low-temperature film formation, and good fullness, without tackiness.
4. Construction industry: Waterborne polyurethane coatings have potential applications in the field of architectural coatings, especially when blended with acrylic emulsions. They can meet the requirements of elasticity, stain resistance, weather resistance, and cost-effectiveness for architectural coatings.
5. Coating industry: Conventional waterborne polyurethane coatings are flammable in the air and have limited water resistance, which restricts their application areas. Extensive research has been conducted to develop specialty waterborne polyurethane coatings, such as flame-retardant coatings, corrosion-resistant coatings, waterproof coatings, and mold-resistant coatings, expanding their application range.
6. In addition to the abovementioned functional waterborne polyurethane coatings, researchers have developed waterborne polyurethane coatings with additional functionalities, such as conductivity, environmental friendliness, shock absorption, biodegradability, and self-healing properties.
Waterborne Polyurethane Adhesives: Waterborne polyurethane adhesives have excellent bonding performance and a wide range of adjustable film properties. They can be used as coating adhesives for various substrates and are widely used in adhesive applications for industries such as footwear, automotive interior decoration, vacuum-formed plastics, and woodworking adhesives.
Waterborne Polyurethane Coatings: Waterborne polyurethane is used as a coating due to its advantages of cold resistance, solvent resistance, film formation, flexibility, resistance to bending, dry/wet rub resistance, and adhesion. It is widely used in applications such as leather coatings, fabric coatings, and automotive clear coats.
Waterborne Polyurethane Ink Binders: Waterborne polyurethane serves as an ink binder, providing excellent adhesion, color development, flexibility, and abrasion resistance in ink formulations.
Hunan GOLD-MINE Company specializes in the production of high-quality and efficient solvent-based and waterborne polyurethane resins, as well as acrylic resins. These products have wide applications in the ink, coating, and adhesive industries. Samples weighing below 500g are available for free. For more information, please contact our company by phone.
Waterborne Polyurethane Resin (WPU) application and usage
2024-01-30
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