Reinforcing material

The primary reinforcing materials used in resin-based composites are glass fibers and carbon fibers. Aramid fibers, ultra-high molecular weight polyethylene fibers, and others.

Glass fiber

Currently, the main types of glass fibers used in high-performance composite materials include high-strength glass fibers, quartz glass fibers, and high-silica glass fibers. Due to their favorable cost-performance ratio, high-strength glass fibers have experienced relatively rapid growth, with an annual growth rate reaching... More than 10%. High-strength glass fiber composites are not only used in military applications but have also seen widespread use in civilian products in recent years, including bulletproof helmets, body armor, helicopter rotor blades, radar radomes for early-warning aircraft, various high-pressure vessels, straight-wing civilian aircraft components, sporting goods, a wide range of high-temperature-resistant products, and, most recently, tire cord fabrics with outstanding performance. Quartz glass fibers and high-silica glass fibers are high-temperature-resistant glass fibers that serve as highly desirable heat- and fire-resistant materials. When used to reinforce phenolic resins, they can produce composite material components with diverse structures that exhibit excellent high-temperature resistance and ablation resistance, making them widely employed as thermal protection materials for rockets and missiles. To date, among the three major reinforcing fibers—carbon fiber, aramid fiber, and high-strength glass fiber—used in high-performance resin-based composites that have been put into practical use in China, only high-strength glass fiber has reached internationally advanced levels and possesses independent intellectual property rights. A small-scale industry has already been established around this fiber, with current annual production capacity reaching 500 tons.

Carbon fiber

Carbon fiber boasts a range of outstanding properties, including high strength, high modulus, high-temperature resistance, and electrical conductivity. It was first widely adopted in the aerospace industry and, in recent years, has also become increasingly popular in sports equipment and sporting goods. According to forecasts, industrial-grade carbon fiber will see large-scale adoption in fields such as civil engineering, transportation, automotive, and energy. Between 1997 and 2000, the annual growth rate of carbon fiber for aerospace applications was estimated at 31%, while the annual growth rate for industrial carbon fiber was projected to reach as high as 130%. Overall, China’s carbon fiber technology level remains relatively low—comparable to the mid-to-late 1970s level in foreign countries—and the gap between China and the rest of the world stands at around 20 years. The main issues with domestically produced carbon fiber include its unstable performance and high coefficient of variation, the absence of high-performance carbon fibers, a limited variety of products, incomplete specifications, insufficient continuous fiber lengths, lack of surface treatment, and relatively high prices. If you’d like to learn more about carbon fiber composites, we’ve previously published many articles on carbon fiber—feel free to check them out.

Aramid fiber

Since the 1980s, the Netherlands, Japan, and the former Soviet Union have also successively launched research and development efforts on aramid fibers. Aramid fibers from Japan and Russia have already been introduced to the market, with an annual growth rate reaching around 20%. Due to their high specific strength and specific modulus, aramid fibers are widely used in high-performance composite material components for aerospace applications—such as rocket engine casings, aircraft engine nacelles, fairings, and rudders—as well as in ships (including aircraft carriers, nuclear submarines, yachts, and lifeboats), automobiles (such as tire cord fabrics, high-pressure hoses, friction materials, and high-pressure gas cylinders), and in heat-resistant conveyor belts and sports equipment.

Ultra-high molecular weight polyethylene fiber

Ultra-high-molecular-weight polyethylene fiber boasts the highest specific strength among all fibers, and it excels particularly in its resistance to chemical reagents and its outstanding anti-aging performance. It also exhibits excellent high-frequency sonar transparency and resistance to seawater corrosion. Many countries have already begun using this fiber to manufacture high-frequency sonar fairings for naval vessels, significantly enhancing their mine-detection and mine-sweeping capabilities. Beyond the military sector, ultra-high-molecular-weight polyethylene fiber holds great promise for applications in automotive manufacturing, shipbuilding, medical devices, sports equipment, and other fields. Since its introduction, this fiber has attracted considerable interest and attention from developed countries around the world.

Thermoset resin-based composites

Thermoset resin-based composites refer to materials made with thermoset resins such as unsaturated polyester resins. Composite materials made by using epoxy resin, phenolic resin, vinyl ester resin, and other matrices, reinforced with materials such as glass fiber, carbon fiber, aramid fiber, and ultra-high molecular weight polyethylene fiber. Epoxy resin is characterized by excellent chemical stability, electrical insulation properties, corrosion resistance, good adhesion performance, and high mechanical strength. It is widely used in various fields including chemical industry, light industry, machinery, electronics, water conservancy, transportation, automotive, household appliances, and aerospace. In 1993, global epoxy resin production capacity stood at 1.3 million tons, rising to 1.43 million tons by 1996, 1.48 million tons in 1997, 1.5 million tons in 1999, and reaching approximately 1.8 million tons by 2003. China began researching epoxy resins in 1975. According to incomplete statistics, there are currently over 170 epoxy resin manufacturers in China, with a total production capacity of more than 500,000 tons and an equipment utilization rate of around 80%. Phenolic resins possess excellent characteristics such as heat resistance, wear resistance, high mechanical strength, outstanding electrical insulation properties, low smoke emission, and superior acid resistance, making them widely used across various sectors of the composite materials industry. In 1997, global phenolic resin production reached 3 million tons, with the United States accounting for 1.64 million tons. China’s production was 180,000 tons, while its imports totaled 40,000 tons. Vinyl ester resins are a new type of thermosetting resin developed in the 1960s. They are characterized by excellent corrosion resistance, good solvent resistance, high mechanical strength, large elongation, strong adhesion to materials such as metals, plastics, and concrete, superior fatigue resistance, excellent electrical performance, resistance to thermal aging, low curing shrinkage, and the ability to cure either at room temperature or through heating. Nanjing Jinling DSM Resin Co., Ltd. has introduced the Atlac series of highly corrosion-resistant vinyl ester resins from the Netherlands, which have been widely used in storage tanks, containers, pipelines, and other applications. Certain grades of these resins can also be employed for waterproofing and hot pressing molding. Other manufacturers, including Nanjing Julong Composite Materials Co., Ltd., Shanghai Xinhua Resin Factory, and Nantong Mingjia Polymer Co., Ltd., also produce vinyl ester resins.

Before 1971, China's thermoset resin-based composite materials industry was primarily focused on military products. Starting in the 1970s, the industry began shifting toward civilian applications. From 1987 onward, various regions extensively introduced advanced foreign technologies, including pultrusion lines using tank furnaces, short-chopped strand mat production lines, surface mat production lines, and manufacturing technologies for a wide range of polyester resins (from the U.S., Germany, the Netherlands, the UK, Italy, and Japan) as well as epoxy resins (from Japan and Germany). In terms of molding processes, the industry adopted technologies such as filament winding pipe and tank production lines, pultrusion lines, SMC production lines, continuous sheet production units, resin transfer molding (RTM) machines, spray-up molding techniques, resin injection molding techniques, and fishing rod production lines. As a result, a complete industrial system has been established, covering research, design, production, and the supply of raw materials. By the end of 2000, China had more than 3,000 enterprises producing thermoset resin-based composites, of which 51 had obtained ISO 9000 quality system certification. The industry offered over 3,000 different product varieties, with a total annual output reaching 730,000 tons—placing China second in the world. These products are mainly used in industries such as construction, corrosion resistance, light industry, transportation, and shipbuilding. In construction, they include interior and exterior wall panels, transparent roofing tiles, cooling towers, air-conditioning covers, fans, fiberglass water tanks, sanitary ware, and septic tanks. In the petrochemical industry, they are primarily used for pipelines and storage tanks. In transportation, automotive components such as body panels, hoods, and bumpers are widely employed; railway vehicles feature carriage panels, doors and windows, and seats; and marine vessels include hovercraft, lifeboats, reconnaissance boats, and fishing boats. In the mechanical and electrical sectors, products like roof-mounted fans, axial-flow fans, cable trays, insulating rods, and integrated circuit boards have also reached considerable scale. In the aerospace and defense fields, significant breakthroughs have been made in the development of light aircraft, tail fins, satellite antennas, rocket nozzles, bulletproof plates, body armor, and torpedoes.

Thermoplastic resin-based composites

Thermoplastic resin-based composites are Developed in the 1980s, the main types include long-fiber-reinforced pellets (LFP), continuous-fiber-reinforced prepregs (MITT), and glass-mat thermoplastic composites (GMT). Depending on specific application requirements, the resin matrices primarily consist of thermoplastic engineering plastics such as PP, PE, PA, PBT, PEI, PC, PES, PEEK, PI, and PAI. Fiber types encompass all possible fiber varieties, including glass fibers, carbon fibers, aramid fibers, and boron fibers. With the continuous maturation of thermoplastic resin-based composite technologies and the advantage of recyclability, this type of composite material has been developing rapidly. In developed countries in Europe and the U.S., thermoplastic resin-based composites now account for more than 30% of the total volume of resin-based composites.

High-performance thermoplastic resin-based composites are predominantly injection-molded, with the matrix being... The primary materials are PP and PA. Our products include pipe fittings (elbows, tees, flanges), valves, impellers, bearings, electrical and automotive components, extruded pipes, GMT molded parts (such as Jeep seat brackets), car pedals, seats, and more. In automobiles, glass-fiber-reinforced polypropylene is used in applications such as ventilation and heating systems, air filter housings, transmission covers, seat frames, fender gaskets, and drive belt guards.

Talc-filled PP boasts high rigidity, high strength, excellent resistance to thermal aging, and outstanding cold-weather performance. Talc-filled PP finds important applications in automotive interior trim, such as components for ventilation systems, dashboards, and automatic brake control levers. For example, the U.S.-based HPM company uses PP reinforced with 20% talc to produce honeycomb-structured sound-absorbing ceiling panels and housing shells for power window lift mechanisms in passenger cars.

 

Mica composites feature high rigidity, high thermal deformation temperature, low shrinkage rate, low flexural modulus, dimensional stability, as well as low density and low cost. By utilizing mica... Polypropylene composite materials can be used to manufacture components such as car dashboards, headlight bezels, fender covers, door guards, motor fans, and shutters. Thanks to the material’s damping properties, it can be used to produce audio components; and thanks to its shielding properties, it can be used to make battery boxes and other similar parts.

Research on thermoplastic resin-based composites in China began with... In the late 1980s, after nearly a decade of rapid development, production reached 120,000 tons by the year 2000, accounting for approximately 17% of the total output of resin-based composites. The matrix materials used were still predominantly PP and PA, while glass fibers remained the primary reinforcing material, with carbon fibers used only in small quantities. In the field of thermoplastic composites, no major breakthroughs have been achieved yet, and there is still a gap compared to developed countries.

Development potential and hot topics

China has great potential for the development of composite materials, but it must address the following hot issues effectively.

Composite Material Innovation

Innovation in composite materials encompasses technological advancements in composites, process development for composites, product development for composites, and applications of composites. Specifically, it is crucial to focus on innovation in resin matrix development, reinforcement material development, production process innovation, and product application innovation. To... In 2007, Asia's share of global composite material sales will increase from 18% to 25%. Currently, per capita consumption in Asia is only 0.29 kg, whereas in the United States it stands at 6.8 kg. This indicates that the Asian region has tremendous growth potential.

Development of Polyacrylonitrile-Based Fibers

China's carbon fiber industry has been developing slowly, starting from... A review of CF development, its characteristics, the domestic carbon fiber development process, an overview of China’s PAN-based CF market, its features, and the status of the “10th Five-Year Plan” science and technology research initiatives all indicate that there is both a need and potential for developing polyacrylonitrile-based fibers.

Glass fiber structure adjustment

Chinese fiberglass More than 70% of these materials are used to reinforce substrates, giving them a cost advantage in the international market. However, in terms of product specifications and quality, there is still a gap compared to advanced countries. It is essential to improve and develop yarns, woven fabrics, nonwoven felts, knitted fabrics, sewn fabrics, and composite felts. Furthermore, close cooperation between the fiberglass and glass-reinforced plastic industries must be promoted to foster new developments in glass fiber reinforced materials.

Composite Materials Market

First, composite materials for clean and renewable energy applications, including composites for wind power generation, desulfurization devices for flue gas, composite materials for transmission and transformation equipment, and high-pressure containers for natural gas and hydrogen. Second, composite materials for automobiles and urban rail transit, covering automotive body shells, frames, and exterior panels, as well as rail transit car bodies, doors, seats, cable trays, cable racks, grilles, electrical cabinets, and other components. Third, composite materials for civil aircraft, primarily carbon fiber composites. Thermoplastic composites account for approximately... 10%, with the main products being wing components, vertical stabilizers, and nose fairings. Over the next 20 years, China will need to add 661 regional aircraft, which will create a large-scale civil aviation passenger aircraft industry. Composite materials can help establish a new supporting industry to complement this growth. Fourth, composite materials for boats and yachts—primarily yachts and fishing vessels. As high-end recreational and durable consumer goods, yachts have a substantial market in Europe and the U.S. Although China’s fish resources are declining and the development of fishing vessels has been relatively slow, the unique advantages of composite materials still offer considerable room for growth.

Infrastructure Applications

Composite materials are widely used both domestically and internationally in bridges, buildings, and roads, offering numerous advantages over traditional materials. They particularly hold great market potential for bridge applications, as well as for reinforcing buildings, tunnel construction, and the repair and strengthening of large storage facilities.

Processing and Regeneration

Focus on developing physical recycling (crushing and recovery), chemical recycling (pyrolysis), and energy recovery; strengthen research on technology pathways and integrated treatment technologies; build demonstration production lines; conduct research on recycling and reuse; and vigorously expand the application of recycled materials in gypsum, in pultruded products, and in... Applications in SMC/BMC molded products and applications in typical products.

In the 21st century, high-performance resin-based composite material technology involves creating intelligent materials that integrate self-healing, self-decomposing, self-diagnosing, and self-manufacturing capabilities. With a focus on developing composites that exhibit high stiffness, high strength, and excellent performance under harsh humid and thermal conditions, we are establishing an integrated materials system encompassing material development, molding and processing, design, and inspection. From an organizational perspective, this approach will involve forming alliances and groupings, thereby making more efficient use of resources from various sectors—both technological and material—and closely leveraging the strengths of each party to further advance the composites industry.

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