Automotive plastics enter new era: High-performance and bio-based plastics are the focus

Today, the automotive industry has evolved to develop in four directions: new energy, lightweighting, intelligentization, and internet of vehicles.

The new energy and lightweighting trends have given a direct boost to the use of plastic parts in automobiles. For instance, the use of interior and exterior decorative parts like plastic bumpers, fenders and wheel housings has become a norm. Also, plastic front-end carriers, plastic tailgates and so on will be key development targets in the next round of product change.

Different from the former two trends with direct impact, the other two trends - intelligentization and internet of vehicles - promote the use of automotive plastic parts in an indirect way because of their needs for large quantities of electrical and electronic products. An example is that flame-retardant plastic materials, such as polyphenyl ether (PPE), polycarbonate/acrylonitrile butadiene styrene (PC/ABS) alloy, and flame-retardant reinforced polyamide (PA), are usually chosen to make the supports, frames and endplates of new energy power batteries.

Although its domestic vehicle production slid in the past year (down to 27.81 million vehicles), China continues to be the largest automobile market in the world. Compared to developed countries, China still has large room for development in terms of car ownership per capita, hence a high potential for the development of the country’s automotive plastic parts industry.

Across the global market, a number of groups are actively developing innovation in automotive plastics. Last year, for instance, saw the birth of the world’s first car with 90% of its key parts and components made in plastics. The concept car was researched and developed under the framework of an innovative technology plan, and completed by scientists from the University of Tokyo in collaboration with automotive producers. Thanks to the use of different kinds of plastics, the car is 40% lighter in weight than ordinary vehicles.

In conclusion, the aim and thinking of developing automotive plastics, which was targeted at reducing the car weight originally, have been gradually widened and enriched. High-performance plastics and bio-based degradable plastics have become the industry’s focal points. With respect to the two points mentioned above, this article will provide a summary of the noteworthy news issues about automotive plastics in 2018 as well as a simple analysis of their characteristics and value when they are used in automotive applications.

High-performance plastics

Polypropylene (PP) and modified PP have been used in large quantities in automotive interior and exterior decorative parts as well as under-the-hood parts. In countries with a well-developed automotive industry, the per vehicle consumption of PP accounts for 30% of the total quantity of all plastics used in a complete vehicle, making it the kind of plastic that is the most consumed in automobiles.

Development planning states that by 2020, the average plastic content of a vehicle is targeted to reach 500kg, or more than one-third of the total materials used in an automobile. However, a big challenge exists in growing the average plastic content of a vehicle by solely boosting a vehicle’s usage of PP and modified PP because the development of these materials has been reaching a bottleneck. Therefore, efforts must be put in developing high-performance plastics, which are light in weight and with strong mechanical performance, if it is to further increase the rate of utilization of automotive plastics.

But every challenge comes with opportunities. For instance, to precisely place a substantial quantity of battery cells in a tiny space, the battery holder, battery support as well as housing assembly must possess exceptionally strong dimensional stability and high mechanical robustness. According to the design principle of battery packs, the choice of material must also be flame-retardant in compliance with the V-0 flammability class of the US Underwriters Laboratories, Inc’s UL94 flammability standard. With respect to combustion engine lightweighting, it is very challenging to replace metal combustion engine parts and components with plastic ones because today’s minimized turbocharged combustion engines can produce very high temperatures.

Nevertheless, the advantages of high-performance plastics should not be left out of consideration. For instance, engineering plastics produce less friction than their metal counterparts in such engine parts and components as timing systems, oil sumps and bearing carriers, which is favorable to increasing the combustion efficiency. Grasping this trend, many companies have over the past year presented how their high-performance plastics can be used.

Bio-based degradable plastics

A report released by the Organization for Economic Co-operation and Development (OECD) reveals that the global plastic waste production has been on a continuous rise since 2015, with more than 0.3 billion tons of plastic waste flowing into the environment every year. This figure is anticipated to reach about 12 billion tons by 2050.

For this reason, as far as the use of automotive plastics is concerned, the issue of being “green, environmentally friendly, renewable and easy to degrade” must also be taken into consideration in addition to expanding the materials’ coverage in automotive parts and components. The key to tackling this issue is bio-based degradable plastics which have advantages including degradability, a wide source of raw materials, low odor, and a low content of VOCs (volatile organic compounds). In the “Made in China 2025” strategic plan, bio-based degradable plastics have been included in the forefront research area of new materials.

In recent years, large-scale automobile manufacturers and material suppliers from across the world have been putting in more efforts in the research and development of bio-based degradable plastics. Ford Motor Company, for instance, has been researching the application of this kind of products since 2008 and now the automobile manufacturer has been using eight kinds of sustainable materials, namely soybean foam, castor oil, wheat straw, Kenaf fiber, cellulose, timber, coconut fiber and rice hull, in automobiles.

Visionary Concept, a concept tire from Michelin.Among suppliers, Michelin has launched a concept tire, Visionary Concept, with an aim to deal with “black pollution” caused by waste tires. Statistics reveal that China generated 330 million waste tires in 2015. Growing by 8% to 10% every year, this figure has reached nearly 400 million waste tires now.

Apart from Michelin, there are other suppliers that have pioneering designs to offer. One of them is the bio automobile team from the Eindhoven University of Technology in the Netherlands, which released a degradable car last year. Called “Lina”, this car was manufactured from bio-based composites made of flax and sugar beet, excluding the wheels and the suspension system, to achieve its greatest advantages of being biodegradable and lightweight.

Lina, a degradable car developed by the Eindhoven University of Technology in the Netherlands.But despite that these concept products are very appealing, the world’s plastics production is about 335 million tons, of which only 1% is bio-based plastics, according to published statistics. This is directly related to shortcomings such as high costs, poor heat resistance, and uncontrollable degradability.

In conclusion, bio-based degradable plastics will develop in the following directions in future. The first is to develop bio-based composites with sufficient performance for use in automotive applications, promote their application and enlarge their market scale. The second is to develop bio-based materials that are low-cost but with high performance. The third is to use bio-based fibers or inorganic long fibers to modify bio-based degradable plastics with the purpose of further improving the overall performance of bio-based plastics and hence promoting their application in the automotive segment.

Conclusion

In automobile production, the use of 100kg of plastics can replace that of 200-300kg of other materials to achieve a fuel saving of 0.5L per 100km. The quantity of plastics used in automobiles of all kinds in China has now reached 130-160kg per vehicle. In particular, the quantity of plastics used in a passenger vehicle has reached to a level that accounts for about 10% of its weight, which is on par with the world’s leading levels (9-12%). In the next phase, the issues of our concern will be how to grasp the development trend and enhance our leadership.