Polyurethane Dispersions

Polyurethane Dispersions for Coatings, Adhesives and Sealants In recent years, rising concerns about environmental issues and sustainability requirements have prompted a shift in industrial demand for coating and adhesive solutions, moving from solvent-based systems toward water-based systems. Access to water-based systems has thus become critical. Witcobond® polyurethane dispersions (PUD), water-based polyurethane systems, offer innovative and effective solutions across many sectors. More than 40 years ago, Lanxess developed Witcobond® polyurethane dispersions (PUD). These dispersions provide users with a system to comply with regulations that impose strict rules on volatile organic content (VOC). Another advantage of PU dispersions is that they help deliver high-performance, high-solids products that can be tailored to specific application areas. Lanxess' product portfolio is completed with proprietary blocking technology, offering fully reacted polyurethane dispersions alongside blocked systems for 1K and 2K bake applications.

Advantages of Witcobond® PUD

• Balanced portfolio of strong performance at high solids grades, • Water-based blocked cross-linkers for 1K and 2K bake systems, • More than 40 years of experience and capability to customize for different applications, • High quality & batch-to-batch consistency.  

Offers Various Solutions to Meet Required Performance and Durability Levels

Witcobond® polyurethane dispersions comprise a broad product portfolio from which formulators can select according to their specific water-based system requirements. Lanxess Witcobond® PUD systems are available in anionic, cationic and nonionic grades, and can be either ether or ester types. Formulators using water-based coating systems can choose from our wide product range. In properties such as hardness, flexibility and chemical resistance, these dispersions enable formulators to achieve different variations.

Key Features:

• Solids contents ranging between 30% and 60% (w/w), • Grades free of auxiliary solvents and surfactants to meet HS&E requirements, • Compatibility with a diverse range of aqueous auxiliary binders such as acrylic dispersions, • Can be combined with pigments, matting agents, flame retardants and other additives.

WITCOBOND® Polyurethane Dispersions Can Be Used in Water-Based Coatings With or Without Cross-Linkers

To enhance properties such as chemical resistance, coating adhesion and durability of a product, Witcobond® PUDs can be cross-linked with various agents. The Trixene® Aqua series from the Lanxess family can be used in 1K and 2K bake systems. The Trixene® Aqua series contains water-dispersed blocked cross-linkers and adhesion promoters. These blocked isocyanates, activated under heat, begin cross-linking with complementary functional groups on the coating and substrate.

Fiber Sizing and Composites

The fiber sizing and composites industry is today one of the rapidly developing and critically important areas. Lanxess' polyurethane dispersions are widely used in the fiber sizing industry. Furthermore, these products can be specifically designed for new requirements. Witcobond® polyurethane dispersions ensure excellent bonding of filaments in fiber and composite processes and deliver superior physical properties in end applications. Witcobond® 374-13 is a polyester-based polyurethane dispersion commonly used as a film former in glass sizing formulations. It provides excellent integrity for chopped strand production and good adhesion to various thermoplastic and thermoset matrices. The adhesion property between fiber and matrix can be further improved by using blocked isocyanate technology. Alternative solutions can be obtained with standard sizing formulations by adding additives such as Trixene® Aqua BI201.

Soft-Touch Coatings

Soft-touch grades such as Witcobond® 374-13 can modify the tactile properties of normally hard surfaces by being incorporated into formulations. Such coatings protect automotive interior surface coatings and base materials of electronic components and add aesthetic properties.

Coating Hard Surfaces

Alternatively, hard products such as Witcobond® 781 and Witcobond® 457-66 can be used for 1K and 2K systems that are chemically resistant and applied to hard surfaces such as wood, metal, glass, plastic, concrete and walls. These application areas may be critical for today's rapidly changing world.

Textile Processing

In textile processing, water-based PUDs such as Witcobond® 363-02 and Witcobond® 737 are used across a wide range of applications. Typical applications include fully waterproof and weather-resistant coatings, back coatings, laminating adhesives, pigment binders used in textile printing and finishes on yarns and fibers for garments. Other functional textile uses include protective coatings on belts, ropes, braids, optical fibers and filament yarns. Lanxess' applied research in water-based technologies delivers more environmentally friendly technologies and chemistry for customers, formulators and end users. Alongside polyurethane dispersions for coating, adhesive and mastic application areas and solutions, the portfolio also includes blocked isocyanates, blocked prepolymers and innovative LW isocyanate systems. All these products can provide key solutions for your systems and enable you to achieve the desired properties in your products. Özlem Erkan Asmaoğlu Technical Sales Engineer, PU & Paint Additives Kimsel Kimya