CFRT (continuous fiber reinforced thermoplastic composite) is a newly developed composite material of high strength, high stiffness and high toughness that is widely used in automobile, aerospace, military, and electronics. Its reinforcement material is continuous fiber that includes glass fiber, carbon fiber, aramid fiber, plant fiber, and basalt fiber. It takes thermoplastic resin as its matrix, such as PP, PE, PA6, PA66, PC, PET, TPU, PPS, PEEK, etc.. According to different property and molding methods, the reinforcement material can be either UD (unidirectional) tapes or fabrics. The two types of UD tapes are both available in TOPOLO T-UD series.

Although long and short fibers are still taking priority of the thermoplastic composite market, continuous fiber reinforced thermoplastic composite (CFRT) keeps growing rapidly in recent worldwide business. International industry magnates have already listed CFRT composite and its related corporations on the objectives of their first development. The acquisition of Bond-Laminates in Germany by Lanxess, QPC by Mitsubishi and Tencate in Netherland by Toray, together with the newly launched CFRT composite by Hanwha, BASF, Covestro, Ineos and other giants in chemical industries also witnessed the ascendant of CFRT.

The Impregnation Technology of CFRT Composite

There are mainly two ways for the integration of thermoplastic resin and continuous reinforced fiber. One is prepreg while the other is called premix, and prepreg is further divided into solvent impregnation and melt impregnation.

Through the flow of liquid resin, every stick of fiber is fully infused and the semi product is called prepreg.

Solvent impregnation

Dissolve the resin into a suitable solution to form the solvent impregnated fiber.

Volatilize the solution and get the prepregs. (complete volatilization for solid premix or half volatilization for viscous and overlayable prepregs)

Advantages:

It overcomes the high viscosity of the infused thermoplastic resin for the complete impregnation of fibers.

Disadvantages:

High recycle cost, pollution, comparatively low solvent resistance

Attention:

The residual solution may cause crafters in the composite material.

It may be hard to find suitable solutions for some kinds of thermoplastic resins.

Melt impregnation

The fibers are pulled through the melted resin and thus impregnated.

Advantages:

It is the most direct and popular way to process thermoplastic prepregs.

Disadvantages:

The viscosity is usually too high for the fibers to be impregnated.

groove structures of melt impregnation

Groove Structures of Melt Impregnation

Solid resin (fiber, powder or film) is evenly distributed in the reinforced fiber before impregnation. The fiber won’t be infused until it meets the flow of the melted resin through heat and pressure in the next process.

The drapability of premix is higher since the fiber is not fully infused with the resin. The even distribution of the resin in the reinforced fiber before infusion greatly improved the quality of final impregnation.

The frequently used methods of premix are hybrid yarn, co-woven, powder impregnation and film stacking.

Hybrid yarn premix

The resin and the reinforced fiber are compactly integrated to form a prepreg of yarn.

Advantages:

The compact integration of fiber and resin shortens the flow distance of resins, which makes the impregnation much easier.

The ratio of fibers is easy to control.

High pliability and drapability, suitable for complicated shapes.

Suitable for various processing methods, weaving, knitting, braiding or unidirectional winding.

Co woven premix

The resin and the reinforced fiber are woven together into tapes, hollow fabrics or other shapes, to form a wrap-knitted fabric. Then the final product–continuous fiber reinforced composite–is formed by thermo-compression.

Advantages:

It is automatic and low cost.

It is a simple process for ready-made fabrics.

The wrap-knitted fabric is easy to keep flat and straight, which loses less property in final products.

It is pliable and suitable for peculiar shapes.

Disadvantages:

Common defects of dry fibers, bubble holes, fiber breakage and the seaming lines hamper its widely use.

Powder impregnation

It applies powdered resin in the reinforcement.

Features:

The resin powder is usually asked to be extremely fine. The finer the powder is, the higher the cost will be. However, more and more research and development are taken on powder impregnation. This technique is prospected in the near future.

Process of Powder Impregnation

Process of Powder Impregnation

Film stacking impregnation

The fabric and the resin film are laminated consecutively and made into composites under heat and pressure. This technique is controversial for whether the melted thermoplastic resin with high temperature can be completed infuse the fabrics.

CFRT Features

★Low discharge, recyclable

★A wide range of suitable materials for thermoplastic resins, much wider than thermosetting resins, for different requirements.

★Easy to store, long storage time

★High fatigue resistance, impact resistance, and erosion resistance

★Low density, high specific strength, and specific stiffness

★Fast molding and multiple molding methods

★Easy to weld

CFRT Molding Methods

CFRT prepreg should be further processed for final products. Thermoplastic prepreg performed better than thermo-setting prepreg during the molding process. The whole process has no chemical changes and can be molded rapidly.

Impact molding
  1. Cut the CFRT prepregs into the mold size.
  2. Heat the CFRT thermoplastic composite sheets in a furnace to a temperature higher than the resin’s melting point.
  3. Thermoforming

The process can be finished between dozens of seconds and several minutes. It is a significant CFRT process for its cost saving, energy saving and high efficiency.

Roll forming
  1. Heat and soften the CFRT prepregs of several layers continuously by far infrared or electric heating.
  2. Forge the CFRT sheets through heating rolls and cooling rolls.

It is also used in metal forming, which is continuous, efficient and unlimited in product length.

Pultrusion
  1. Preheat the prepregs.
  2. Forge the CFRT tapes through one or several molds into specific shapes.

It is usually for CFRT tapes or fiber bundles to form products in relatively regular geometric shapes such as rods, grooves, beams, etc..

Vacuum molding
  1. Cut the CFRT sheets into required sizes.
  2. Preheat the sheets and move them onto the metal molds.
  3. Seal the outer periphery of the sheets and the mold, then apply vacuum in the cavity to lay the sheet on the mold.
  4. Release the mold after cooling and get the desired shapes.

Vacuum molding is also suitable for CFRT thermoplastic composite sheets.

CFRT Application

The advantages of CFRT are more than its disadvantages. The continuous fiber reinforced composites of carbon fiber and aramid fiber have become a special material indispensable for aircraft and aerospace. Besides, continuous glass fiber reinforced composites are also used in automobiles, electronics, architecture, and logistics. Continuous fiber reinforced thermoplastic composites are especially concerned by vehicle industries. Core components (bumper, engine dumboard, seat framework, front lamp, fans, radiator barrier, dashboard carrier, etc.) made of CFRT have appeared in Japanese and Euramerican markets. In China, Beijing Jeep also began to use continuous glass fiber reinforced thermoplastic composite sheets (GMT) in the seat plate.

For commercial vehicles:

Lightweight solutions for commercial vehicles mainly focus on the panels of cargo vans and the structural components of passenger cars. The replacement of traditional glass steel and metal panels by continuous fiber reinforced PP honeycomb sandwich panels greatly reduced the total weight of vehicles. Statistics show that every 100kg reduction of weight saves 0.6L oil consumption, removes 10% rolling resistance and brings 6%-8% fuel efficiency and 3% combustion efficiency.

Take 9.6m cargo vans for example. Out panels of carriages made by continuous fiber reinforced PP composites are 1000kg lighter than metal carriages, 800kg lighter than wooden sandwich panel carriages and 500kg lighter than glass steel carriages. It’s experienced that every 1000kg weight reduction can save oil consumption 3-6L per 100km. It’s also estimated that every set of PP honeycomb panel car can save oil cost RMB52000 per year (200000km/year).

For passenger cars:

Continuous fiber reinforced thermoplastic composites are currently adopted more by international enterprises. The compression molding and injection technology used in fiber reinforced thermoplastic sandwich panels make the products more cost-efficient, more lightweight and more strengthened.

For railway transportation:

The fire retardant PP UD tape laminated with glass fiber is often used in the inner panels of carriages as the replacement of traditional bamboo plywood. It is more protectable to the carriage, more lightweight and more energy saving.

The strong impact resistance and rapid molding of CFRT composites are typically suitable for high-end sports shoes, helmets, draw-bar boxes, cell phone shells, etc.. Nike series, a faithful user of CFRT composites, adopts carbon glass hybrid thermoplastic composite sheets into its arch support plates. The hot sales of Nike shoes also popularized the carbon sheets.

Besides shoe materials, continuous fiber reinforced thermoplastic composites are also used in electronic and recreational products. The process of carbon glass hybrid thermoplastic composite sheets is complex and the infusion is difficult. How to infuse the resin into both carbon fibers and glass fibers is the key point.

CFRT in aerospace often takes high performance carbon fibers, aramid fibers and glass fibers as reinforcement and PEEK, PPS, PES as resin matrix, whose temperature resistance can be up to 425℃. Such thermoplastic resins are under hot development for its high temperature resistance.

In aircrafts, carbon fiber and fabric reinforced PPS composites are used in the leading edge of A380. Apart from external parts, PPS composites are also used in seat frames, cross beams and admission pipes.

Metal speculums in spacecrafts used to be too heavy to achieve the design until the replacement of PEEK continuous fiber reinforced composites.

In addition to the advantages as thermoplastic composites, PEEK features self-extinguishing, low smoke, non-toxic and fire retardant. It is also widely used in medical field for its special characters of X-ray transmission, excellent biocompatibility and strong antibacterial properties. It can be implanted into human bodies for a long time as it’s elastic modulus is similar to bones.

G-series high speed trains, marine industries, fan blades, gas cylinders

Traditional Material VS Fiber Reinforced Thermoplastic Material
Traditional Material VS TOPOLO CFRT Material

Core technologies of CFRT UD tapes, 0/90° thermoplastic composite sheets, and honeycomb sandwich panels have been mastered in China, and in TOPOLO, our products T-UD series CFRT tapes, T-PC series CFRT sheet and T-SP series sandwich panels are also undoubtedly competitive both in price and in quality.

With the growing requirements of lightweight and recyclable composite materials, CFRT will certainly become more and more popular in future markets.

 CFRT in Transportation

CFRT-Applicatopn-in-Transportation

  • Rail & Subway: Floor, lining and roof;
  • Automotive & Ship: Automotive interior & exterior; ship decorative panels, truck cargoes, trailer containers

CFRT in Sports Tools

CFRT-application-in-Sport-Tools

  • Sports Tools: Snowboards, sleds, surfboards, diving boards, oars;

CFRT in Pipes, Military,  and Aerospace

CFRT-application-in-Pipe

  • Pipes: Used in the pipe structural ply, to make pipes even stronger and more durable by the winding process of extra reinforcement.
  • Military: CFRT can be made into laminated sheets and panels to produce ballistic panels, bulletproof armors, missile storage boxes, etc..
  • Aerospace: Products and components where light weight and strength are both highly required, such as Unit Load Devices (ULD)

CFRT in Construction

CFRT-application-in-Construction

  • Movable Units: stalls, stands in movable areas, temporary sheds, mobile shops, promotional tables, shelves, newsstands, playhouse, temporary shelters, portable and removable shower rooms, etc.
  • Furniture/ office: partitions panels, doors, floors, countertops, cabinets, (movable) furniture, etc.