Automotive composite materials-lighter and more flexible solutions

Sandeepan Mondal, senior research analyst at Frost & Sullivan, predicts that thermoplastics have advantages over thermosets because they are easier to recycle than thermosets. This becomes even more important as waste regulations and the ability to recycle parts have an increasing influence on material selection.

The huge market demand for these two materials has become the main driving factor for two major acquisitions. *The most recent incident occurred in January 2013. The Dutch company TenCate said it was about to acquire Amber Composites (Amber Composites). The Dutch company issued a statement saying: “A major component of the global composite materials market is thermoset materials. TenCate’s main business in this market is concentrated in aviation, aerospace and radome applications.”

TenCate added: The acquisition of Amber Composites will help us accelerate our business in the European thermoset composites market. Therefore, after the acquisition of Amber, TenCate has increased its market share in the thermoset and thermoplastic composite materials field in Europe and its main downstream markets-industrial and automotive composite materials, mold materials and aerospace markets. ”

The second acquisition was in 2012 when Cytec acquired Umeco. Cytec Industrial Materials (Cytec Industrial Materials) global automotive market manager Alexander Aucken said: “This acquisition will help us achieve our goals in the industrial materials (including automotive) market. Growth targets, this market has huge growth potential and value creation space.”

Before the completion of the acquisition, Cytec had “has a full range of thermoset and thermoplastic composite materials.” As he said, Umeco’s production capacity will help Cytec develop and expand its product line.

Aucken did not disclose Cytec’s development strategy in automotive thermoplastics and thermosets. But he said: “Our strategic plan for the industrial automotive market is very detailed and progressing smoothly. Our alliance with Jaguar Land Rover is part of this strategic plan. The automotive market is constantly changing. The racing market’s long history of supplying advanced composite materials is continuing, and new composite materials are constantly being developed to meet the needs of the market. Materials suitable for mass production, the development of production processes and automation processes, and the centralized management of the supply chain are The cornerstone of our future growth in this market with Jaguar Land Rover and other auto companies that cooperate with us.”

Aucken believes that as the automotive industry continues to gain experience in composite material design and production, the use of composite materials and the need for structural integration will increase. Apply the right materials to the right applications, and then connect them, that is, using matching molds, thermosetting composite materials (prepreg compression molding and resin transfer molding/RTM) and thermoplastic composite materials. This approach makes multi-material automotive solutions gradually become the industry norm.

Pros and cons

Having experience in both thermosetting and thermoplastic materials will definitely be of great help to Cytec and TenCat, because some designers like to use thermoset materials, and some like to use thermoplastic materials. Klaus Ritter, marketing manager at Huntsman Advanced Materials, explained that the process of part design is usually also a process of evaluating the benefits and disadvantages of each composite material.

“Thermoplastic composites have three major advantages.” itter said, “First of all, the impact resistance of thermoplastics is unmatched by thermoset composites. Thermoplastics can speed up the processing speed of pre-impregnated fiber materials. The most important thing is that it has The ability to reshape the product at any time. However, because thermoplastics are originally solid, fiber infiltration is more difficult. Infiltration requires special technology and equipment. This relatively increases the cost of pre-impregnation, and the processing requires a higher temperature High, it also increases daily production costs.”

Ritter continued: “Other disadvantages of thermoplastics include their creep properties and high internal tension, which are caused by the different thermal expansion between thermoplastics and reinforcing fibers when they cool down from high processing temperatures. The problem of unidirectional reinforcement is relatively small, and the complex three-dimensional shape has a big problem, and it will also cause a decrease in surface quality.”

“The processing time of thermoset composites is usually relatively long. Now you can use the high-pressure RTM (resin transfer molding) rapid prototyping method outside the autoclave to achieve a five-minute cycle (one minute injection, two minutes curing), which is not too complicated for compression molding. Operation, each part only takes two minutes (curing only takes one minute).” He said.

According to Ritter, in structural applications, the mechanical properties and corrosion resistance of thermoset composites made of fiber-reinforced epoxy resin are “even higher than metal parts, and the weight is much lighter than metal. Thermoset composites have good fiber The wettability and relatively low processing temperature help reduce investment costs and maintain the best product quality and mechanical properties.”

According to Ritter, thermoset composites have the lowest creep deformation. They “combine shape and function to create very light structural parts. Whether the car parts are carbon fiber appearance or sprayed surface, they can get a very good surface. Quality. However, toxicity issues are often seen as a shortcoming of several thermoset systems.”

According to Francis Defoor, director of global transportation marketing at Momentive Specialty Chemicals, which is better, thermoset or thermoplastic, the question itself is wrong. He said: “This is a more complicated problem than simply choosing a resin and a reinforcing material. You must choose the right material according to the specific application and environment. The choice of material depends on whether you need a good decorative part. It’s still a structural component; is it to adapt to a specific geometric shape or to meet a specific cost target.”

Defoor agrees that traditional thermosetting resins need to be cured for a long time, but now a two-minute processing cycle can be achieved without sacrificing other properties. In a paper titled “Advanced Thermosetting Resin Matrix Technology for Next Generation High Volume Manufacture of Automotive Composite Structures” (Advanced Thermosetting Resin Matrix Technology for Next Generation High Volume Manufacture of Automotive Composite Structures), Dr. Roman W. Hillermeier, Tarecl Hasson Doctor, Lars Friedrich? And Cedric Ball believes that epoxy composites can compete with traditional materials, such as steel and aluminum.

In the abstract of this article, the authors stated: “…the new technologies are sacred, because they have a long enough injection processing window, can well infiltrate the reinforcing fibers, and can also achieve a very short curing cycle. The results of this study show that using the current innovative resin materials and processing technology, structural composite parts can be mass-produced at a lower cost.” Momentive said, the newly launched rapid curing system EpikoteTM Binder 05475/Epikure 05500 curing agent can help automakers achieve higher productivity with the help of RTM or liquid compression molding process.

Celanese’s engineering plastics business Ticona believes that thermoplastic tape is the key to reducing weight.

At the 2012 JEC American Composites Exhibition, Ticona’s technology launch manager Michael Ruby published a technical article on glass fiber reinforced thermoplastic composite unidirectional tape. Improving impact performance in D-LFT composites with UD-Tape based fabrics & laminates” (Improving impact performance in D-LFT composites with UD-Tape based fabrics & laminates) Research on underbody shield (UBS) describes a method to improve the hardness/strength and impact resistance of composite materials, that is, the use of continuous strands, glass fiber reinforced thermoplastic composite unidirectional tape to produce fiber fabrics and custom laminated blanks.

Ticona believes that the combination of thermoplastic polymers and continuous fiber composite materials can produce lightweight and durable parts. Ticona said these components can reduce weight, reduce costs, and can be used in extreme environments.

The company has developed an automotive underbody shield made of long-fiber reinforced thermoplastic composite material in-line compounding technology (D-LFT). The composite materials used are reinforced with continuous fiber semi-finished fabrics and laminated materials to improve hardness and impact resistance.

Carbon fiber

Increasing competition among companies and faster curing cycles are likely to prompt more automotive designers to adopt reinforced polymers. The integration of components has been going on for many years. As Axon Automotive is confirming, there is still a lot of work to be done in this area.

British company Axon has developed a city car. The size of this B-class car is very close to the Citroen Cl, but it is said that the weight of the entire body frame is only 50 kilograms.

Light-duty vehicles can reduce fuel consumption and exhaust emissions to the lowest level. The market demand for light-duty vehicles has prompted the company to develop a “black body” carbon fiber composite system. It is said that the “black body” system of a city car weighs only 50 kilograms; a medium-sized sedan weighs only 80 kilograms. oAxon also said that there are methods that can quickly build an economical car platform, and that can be increased as demand changes. *Good initial output has huge development potential.

“The higher the degree of structural integration, the fewer parts need to be manufactured,” explained Steve Cousins, general manager of Axon.

Cousins ​​said that there are 350 parts in a classic white body, while the number of parts in the black body of Axon is smaller and the manufacturing speed is much faster. According to Cousins, a 3-meter-high beam requires only 10 minutes of infusion molding time.

Axon uses Axontex technology to manufacture very light but very strong and rigid composite structural beams. The company said that this system can not only meet all hardness and crash standards, but also can use any material you need in the exterior body panels, from steel to thermoplastics and anything in between. The company’s carbon fiber composite resin system Crestapol 1250 LV, developed in cooperation with Scott Bader, has been used in the body frame of its city car to achieve lower cost and higher strength.

Ford Motor Company is also using carbon fiber materials, and the company is cooperating with Dow Automotive Systems to study the application of advanced carbon fiber composite materials in production vehicles. One of the main elements of Ford’s fuel efficiency strategy is to reduce the weight of new cars and trucks by 750 pounds (about 340 kg) by 2020.

Ford Chief Technology Officer and Vice President Paul Mascarenas explained that there are two ways to reduce car fuel consumption: research and innovation. They are “studying how to improve the efficiency of fuel-to-power conversion and reduce the work required by the powertrain.”

“Ford mainly solves the conversion problem by reducing the size of the engine and electrical equipment, and the reduction of the curb weight and the improvement of the dynamic performance are the keys to reducing energy consumption.” He said, “Ford is working on a series of new materials, Improved design processes and new manufacturing technologies are investigated. They can enable cars to meet increasingly stringent safety and quality standards while reducing weight.”

“We have made some progress through the use of lightweight and high-strength polymers and structural connection technology, so the cooperation with Ford is a natural thing.” said Florian Schattenmann, Director of Dow Automotive Systems Research and Development.

Dow and Ford have signed a cooperative development agreement, and the two parties will cooperate in several areas for joint research and development. This R&D team will work to establish an economical carbon fiber resource for vehicles and develop a method of manufacturing parts suitable for mass-produced vehicles. This cooperation will combine the outstanding advantages of both parties*, including Ford’s capabilities and experience in design, process, and production car production, as well as Dow’s advantages in R&D, material science, and quantitative polymer processing.

This joint development will also utilize the research work carried out by The Dow Chemical Company through cooperation with the Turkish carbon fiber manufacturer AKSA and the Oak Ridge National Laboratory (ORNL) of the U.S. Department of Energy.

If this cooperation can be successful, then carbon fiber parts may appear in Ford’s new cars later in this century. The goal of the product development team is to meet new fuel efficiency standards above 50 mpg (miles per gallon) and to extend the range of electric vehicles.

Recycle

Now designers are very picky in the choice of polymers and reinforcement materials. However, Nigel Keen, a business support engineer at the National Composites Centre in Bristol, UK, said that processing speed is currently the most favorable factor for thermoplastics* compared to recyclability. Because now whether it is thermoplastic or thermosetting plastics, there are recycling solutions that meet EU standards. However, recycling is still a problem, even though automakers have already considered this issue when designing parts.

It is said that the use of thermosetting materials can achieve 100% recycling. Bruce Ogilvy, marketing manager of oEco-Wolf, said that the company’s recycling system will become more and more popular because the automotive industry is facing a pressure on how to prove that thermoset There are viable recycling methods for parts made of materials.

“As the cost of raw materials continues to increase, and the relevant regulations for landfills continue to develop, the ability to reuse waste has become more and more attractive.” Ogilvy said, “However, at first, a certain percentage of pure materials was replaced with recycled materials. The cost savings are not ideal. Because when the cost of landfill decreases, other related expenses increase, so the reduced cost becomes the main consideration. We are currently cooperating with some companies to establish fiber The recycling plant recycles both glass fiber reinforced materials and carbon fiber composite materials.”

Eco-Wolf’s recycling system mainly consists of two parts. One is the Eco-Grinder. This equipment has a solid structure and is specially designed to deal with the abrasiveness of the material while maintaining the integrity of glass fiber or other natural fibers. sex. This allows fibers to be added back to new products.

The second part is an Eco—Dispensing Macerator. This is a pneumatic device that can measure the material from the Eco crusher and transport it to the existing dispersing equipment, and from there according to the operator’s Requires injection into the resin stream oEco-Wolf provides an adapter that can reuse waste without changing the resin system.

Ogilvy said that Eco-Wolf “developed an excellent carbon fiber processing method because there is no need to heat the carbon fiber during the recycling process, so it will not significantly reduce the tensile strength of the carbon fiber.” * In the end, the designer may be forced to Make compromises. This is because the choice of polymer and carbon fiber materials may depend to some extent on how easy it is to automate the process. In addition, although the curing time has been shortened in some processes, the introduction of a new composite material production process in an automobile factory is not simply a matter of finding out all the variables, such as design, material, size, and cost. It is also necessary to have a deep understanding of the effects of secondary processes, such as spraying processes. It is interesting to see how automakers achieve their future weight loss goals.

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