Automotive

Polyurethane Coatings in Automotive Coatings – Superior Protection and Aesthetic Excellence

The coating of a car body is a multi-layer high-tech system needing to serve many purposes. 

While the first layer, a CED protects mainly against corrosion whereas the second layer, the primer, provides dampening properties to protect against mechanical impacts like stone chips. Also, this layer smoothens any unevenness of the surface. Both of these layers predominantly use epoxy-based chemistry. 

Polyurethane (PU) coatings are more typically used in subsequent upper layers. The base layer is the actual layer that contains all pigments and provides the colored appearance of the car and therefore serves a more decorative purpose. Typically water-based polyurethane dispersions (PUDs) are the system of choice here. 

The final layer is the top-coat, which combines decorative and protective purposes to the highest level. To provide a smooth surface for a perfect gloss, excellent leveling of the system is required. This needs to be combined with the highest demand in protection, the sources of damage are threefold. First, the underlying coating layers must be protected against UV irradiation to prevent polymer degradation. Second, chemicals like gasoline, tree gum, bird droppings etc. attack the top coat directly. Finally, also mechanical impacts like scratches must be prevented – they do not only impact the appearance but can also damage the entire coating to an extend the protective barrier is impaired. 

PVC Plastisols are widely used in the automotive industry particularly in paint shop applications where they fulfill several crucial functions. These primarily include corrosion protection for metal surfaces, waterproofing, bonding and sealing of seams and joints, as well as protection for external surfaces such as underbody constructions, rocker panels and sills. One critical factor impacting the performance of PVC plastisols in such applications is their adhesion to the target substrate, mostly e-coat primed steel, which can be significantly improved using adhesion promotors typically based on polyamide or blocked isocyanate chemistry. 
Under the Nourybond® brand we offer a broad range of products that enable PVC plastisol developers and formulators to tailor their products to meet the various requirements and challenges that come with the evolution of e-coat primer systems and related processes.

Recent technical developments in adhesive bonding has delivered improved joining processes that have enabled extremely lightweight and increasingly more complex multi-material designs in the automotive and electronics industries. Our comprehensive range of amine-based curing agents enables adhesion to different substrates and composite materials consisting of different materials, such as metals, polymers, glass and ceramics.  

Ideally suited for improving adhesives joining applications, our high-performance one- and two-component structural epoxy systems provide the exceptional adhesive and sealant solutions you need to meet the latest performance, sustainability, safety and efficiency demands.

Structural adhesives are a strong, cost-efficient and fast joining technology and have become increasingly important in industrial manufacturing. In particular, the fields of automotive and electronics have highly benefited from the technical development of adhesive bonding technology. Lightweight and multi-material designs, progressive integration and miniaturization as well as increasing complexity have created a steady rise in technical requirements on components and thus also on bonding processes.  

The success of epoxides in structural adhesives primarily stems from their excellent mechanical properties, very good adhesion to a wide range of substrates, and exceptionally good resistance to environmental influences such as moisture, chemicals and temperature. In addition, they shrink only slightly during curing and generally contain no volatile matter. Depending on the target application, epoxy adhesives can be formulated as one-component or two-component systems and can be cured at elevated or ambient temperature.  

Crosslinkers particularly offers a wide range of high-quality amine-based curing agents and accelerators for structural epoxy adhesives. The curing agent itself can be considered one of the most important components in the epoxy adhesive formulation as it has specific influence on crucial process parameters such as application form, mixing ratio, viscosity, processing time, curing temperature and curing rate which can be adapted to the target application. But selecting a suitable curing agent is also crucial regarding the required final properties of the adhesive including mechanical strength, flexibility and impact strength as well as thermal and chemical resistance.  

Crosslinker’s curing agents for structural one-component and two-component epoxy adhesives including the brands Ancamine®, Ancamide® and Amicure® as well as Curezol® and Imicure® cover almost the entire range of current amine curing technologies. This range comprises not only aliphatic and cycloaliphatic amines, but also polyamides and amidoamines as well as imidazoles and diverse dicyandiamide grades.