Black car application of fiber-reinforced plastics (FRTP application)
Application

FRTP: filled and reinforced compounds

Two reasons in favour of fillers: optimization of the composite material properties and cost savings

There are basically two reasons for working fillers into a plastic matrix: to optimize the compound material properties, such as for breathable foils or sound-absorbing pipes, or to save costs.

Typical areas of application

Black granulate from fiber-reinforced thermoplastics
BUSS compounder technology is first choice for the production of raw materials parts from fibre-reinforced plastics
Fiber-reinforced plastics manufactured with BUSS FRTP compounding systems are often used for all kinds of kitchen appliances
White granulate from fiber-reinforced plastics – FRTP compounding
Dark violet granulate from filled and reinforced thermoplastics/compounds processed using BUSS compounding systems

Three variables play key roles in the interaction between fillers and polymer matrix.

  • Particle shape: a low aspect ratio such as glass beads, CaCO3 or BaSO4 generally improves the elasticity module, while a large aspect ratio, such as talcum or wollastonite, tend to improve tensile and tear strength as well as the modulus of elasticity.
  • Particle size distribution affects how well the fillers are worked in. Important here are the Van-der-Waals cohesion forces between particles (at particle sizes > 1 μm), and the dispersive shear forces exerted by the BUSS Co-Kneader (at particle diameter < 10 μm) for the FRTP compounding systems.
  • Surface area of the filler: the number of potential cohesion points between fillers and polymer chains depends on the specific surface area (m²/g), of the fillers. The larger the fillers’ surface area , the more cohesion points and the stronger the material (rigidity, tensile strength, tear and impact strength).

Surface coatings are another important aspect. They can for example influence agglomerate formation, material flowability for easier handling, and adequate wetting during compounding.

Further insights into our options for the plastics industry

Benefits

BUSS compounding systems offer the following specific benefits for FRTP compounds

The BUSS compounding machine technology allows high filler loadings by splitting to 2-3 feed positions, use of feed-in processes such as side feeders, gravimetric dosing units, back venting and excellent conveying efficiency. The moderate Co-Kneader shear rates allow effortless handling of the high viscosities arising with high filler loadings.

Uniform shear rates allow controlled mixing in the compounding machine at lower temperatures while imparting only the required shear energy for the task at hand. The narrow shear rate distribution compared to alternative systems ensures uniform shear histories for every individual particle. This results in high-quality processing with reduced energy input.

The moderate shear rates of the BUSS Co-Kneader guarantee controllable shearing and low temperature profiles, and impact fiber structures and highly-structured fillers such as carbon black considerably less than other systems. This results in better mechanical and electrical properties, improved flow characteristics and lower consumption of expensive additives.

Latest generation multi-flight BUSS compounders achieve a better mixing effect with a low overall specific energy input. This is because there is a high number of mixing cycles, optimally attuned to the respective process zone. The energy required for melting is almost exclusively introduced mechanically (dissipated) as shear energy.

The BUSS Co-Kneader allows precise temperature control due to controlled energy input and uniformly moderate shear rates as well as their temperature monitoring by thermocouples, which are mounted in drilled kneading pins surrounded by polymer at relevant positions along the process section.

Compounding requirements

of fiber-reinforced plastics

BUSS process expertise is the key to manufacturing fiber-reinforced plastics: in addition to optimal distribution of the material flows, it is particularly important to have command of the air and humidity flows accompanying filler input.

Consequently, the process geometry must be optimally configured for these tasks. With corresponding configuration, the large free volumes and their corresponding torques allow the efficient production of these fiber-reinforced plastics.

The excellent all-rounder qualities of the BUSS Co-Kneader with its extremely wide operation window enable mostly highly varied related processes including fillers such as talcum, titanium dioxide or barium sulfate as well as aluminium or magnesium hydroxides.

The considerably lower wear and tear compared to alternative screw extruders denotes a positive side-effect of the BUSS Co-Kneader’s moderate shear rates. The modular and therefore adjustable design of the entire compounding system make the BUSS Co-Kneader an excellent choice for compounding filled thermoplastics.

Typical plant layout

COMPEO compounder for FRTP compounding

Take a look at our typical plant layout for the production of filled and reinforced plastics in our COMPEO showroom.

Discover our COMPEO compounder

BUSS Co-Kneaders

worldwide

Our patented BUSS Co-Kneaders are used worldwide nowadays, supporting our customers in plastics production. Using BUSS compounding systems, our customers can master all the demanding requirements for FRTP compounding.

World map with an overview of the Co-Kneaders used for manufacturing performance compounds.

Number of Co-Kneaders used for manufacturing performance compounds

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COMPEO series

We present: COMPEO, the state-of-the-art compounder that offers more versatility in its application, higher flexibility in process engineering, and increased added value in compound manufacturing.

Natural fiber-reinforced plastics

For many centuries, people used natural materials as primary materials. Wood was used for building houses and ships, flax and hemp fibre were processed as ropes and technical textiles such as sails and grain sacks.

Plant and System Solutions

Custom compounding systems from BUSS: tailor-made concepts, integration of all components, precise assembly, and smooth commissioning. Comprehensive expertise results in sustainable compounding solutions for a wide range of material applications.