Uses of Polyurethanes in the Automotive Sector

Polyurethane Applications in the Automotive Sector Polyurethane materials, produced by reacting polyols with a diisocyanate in the presence of suitable catalysts and additives, are utilized in many sectors. The automotive sector is among these, and polyurethane foams are used in vehicles. When looking at the automotive sector, one of the main concerns of engineers is the reduction of vehicle weight. The primary reason for this is that lighter vehicles consume less fuel and consequently produce lower CO2 emissions. Engineers working on this issue take advantage of polyurethane foams due to their lightness in many applications, particularly in automotive seats. For the same reason, composite materials are also frequently used in the automotive sector. Polyurethanes fall within the polymer class. To clarify the definition above; polyurethanes can also be defined as polymers consisting of a chain of organic units connected by carbamate bonds. There are several polymeric materials suitable for and used in the automotive sector. Among these materials, (PU) foams are among the most suitable polymeric materials for use in the automotive industry. PU foams are mostly used in vehicle seats, and PU foams help provide drivers and passengers with the comfort they need. However, this is not the only advantage it provides; since PU foam materials are lightweight, they also provide the car with better mileage performance and better fuel efficiency. In addition to the advantages of PU foams, when their ability to maintain their structure while being shaped is considered, this makes them a preferred material in automobile interiors, dashboard panels and similar places.

Use of Polyurethanes in Automobiles

The general advantages provided by polyurethanes can be listed as follows: High wear resistance, High resistance to aging, High elasticity, High toughness, Chemical stability, Radiation resistance, High processability. Thanks to these advantages, polyurethanes are used in many sectors. Another advantage of polyurethane is that it can be produced in the desired hardness. In processing these materials, extrusion, injection molding, film blowing, solution dipping and two-part liquid molding production methods can be used. Polyurethane foams used in the automotive sector are mostly used in the interior parts of automobiles. Bio-based polyurethanes are preferred especially in these interior parts because they offer better impact resistance. At the same time, bio-based polyurethanes help reduce CO2 emissions and are much more environmentally friendly compared to their petroleum equivalents and provide higher performance for automobiles. Bio-based PUs have been frequently used recently in automobile gauge and door panels, and gear shift levers. Another superior feature provided by polyurethane foams in vehicles is vibration reduction. Especially in high-vibration vehicles such as tractors and trailers, it reduces vibration and provides a smooth driving experience. Polyurethane foams provide high comfort not only in automobiles but also in vehicles such as aircraft and marine vessels. They are especially frequently used in aircraft seats. In marine vessels, polyurethanes help eliminate corrosion and mold formation. Among the places where polyurethanes are used in automobiles are filter systems and sound insulation systems. Looking at polyurethanes in filter systems; they are used in air and oil filters. The other area of use is sound insulation. Here, it helps reduce the energy of sound waves entering the vehicle and absorbs sounds. This is among the factors that increase driving comfort.

Polyurethane Resins

Another area where polyurethanes are utilized is resins. These resins have high chemical resistance and show high resistance to dust and moisture. At the same time, they have a more flexible structure compared to frequently used epoxy resins. Thanks to this flexible structure, they do not break easily and are also more resistant to scratches. Thanks to these advantages, they can be used on the exterior surfaces of vehicles. The greatest advantage polyurethane resins provide on vehicle exteriors is their resistance to aging. This provides a longer service life. Another advantage is its high UV resistance and high resistance to weather conditions. It shows resistance to moisture and contamination. Polyurethane resins provide high gloss. This allows details in vehicle design to stand out better and for this reason they are preferred.

Polyurethane Adhesives

Another area where polyurethane is used is adhesives. Polyurethane adhesives can be easily applied to different materials and show high resistance to both water and solvents. Good adhesion resistance to different structures and flexibility are among the reasons polyurethane adhesives are preferred. Looking at other advantages; they have fast curing time, they can react at low temperatures. At the same time, they show resistance to chemicals and oils. Thanks to these advantages, polyurethane adhesives are also used in the automotive sector. In automobiles, adhesives occupy a large space and are among the most important materials. Polyurethane-based adhesives are preferred due to their durability and elasticity. Polyurethane adhesives are also used in high-performance composite materials produced for use in automobiles.

Corrosion Protection

One of the biggest problems in vehicles is corrosion formation. If corrosion occurs, repairing that area of the vehicle is quite difficult and that area needs to be removed and repainted with primer and paint. For this reason, corrosion protection is important for vehicles. Polyurethanes are also used in the automotive sector for this purpose. Here, after sealing operations are performed, polyurethane is used to fill the remaining gaps. With this application, heat and sound insulation are also provided. Polyurethanes are preferred because they are a corrosion-resistant material.

Composites

Composites are created by combining multiple materials, and different materials can be used in composite production. Polymers are among these materials, and polymer matrix composites are particularly utilized in the automotive industry. Polyurethane can also be used as this polymer. To improve the properties of polyurethane materials, additive materials can be added. Here, emphasis is especially placed on improving thermal, mechanical and barrier properties. Due to properties such as lightness, low production cost and flexibility offered by polyurethanes, their use in the automotive sector is increasing. Especially because of their light weight, as fuel economy has become increasingly important today, this has increased the use of polyurethanes in automobiles. Polyurethanes, which can be used in many areas from car seats to sound insulation, offer many advantages. In future periods, as fuel efficiency becomes even more important with the climate crisis, it is expected that polyurethane materials will be used even more in vehicles. References: https://tr.wikipedia.org/wiki/Poli%C3%BCretan Improving Surface Properties of Molds Used in the Production of Polyurethane Parts in the Automotive Industry - Ebutalip Çobanoğlu https://www.turkchem.net/otomotiv-sektorunde-poliuretanlar.html https://www.sciencedirect.com/science/article/abs/pii/S2211285522000970 Compiled by: Nilsu Kotil