Technology KneaderReactor High-viscosity processes in the concentrated phase. Solvent-free. Scalable. first-hand Process knowledge Our specialists support your project from concept to production. conventional boundaries Beyond LIST KneaderReactor Technology is used whenever conventional processes reach their limits. without compromises Process reliability LIST KneaderReactors ensure maximum uptime, process reliability, and product consistency—even in the most challenging processes.

Excellencein Process Intensification

The LIST Kneader Reactor. Designed and tested for highly viscous, sticky, and/or solidifying products that push other machines to their limits.

LIST KneaderReactor Technology represents a Conti process approach in the concentrated phase—for highly viscous, sticky, and solidifying materials. Scalable process intensification from the laboratory to world-scale plants. As one of BUSSLIST Group’s three technology platforms, the Kneader Reactor combines the processing capabilities of extruders, evaporators, dryers, continuous stirred reactors, and Z-kneaders in a single continuously operating machine.

Its roots go back to Heinz List, the inventor of the Co-Kneader at BUSS, who later founded LIST and developed the KneaderReactor Technology.

Today, LIST Kneader Reactors enable the production of materials worldwide that could not be manufactured with comparable efficiency and safety on the same production scale using other machines—ranging from synthetic rubbers and cellulose fibers to high-performance polymers, as well as active pharmaceutical ingredients and recovery and recycling processes.

The Kneader Reactor Key features for your process

No product buildup, no crust formation. The complete self-cleaning of the mixing elements enables phase-change processes. It continuously prevents the formation of crusts and product buildup. This allows for the drying of solidifying products, such as the processing of residues, or purification via desublimation.

The mixing energy of the LIST kneader reactor is an important source of energy input for evaporation processes. The shaft speed directly determines the product temperature through friction (dissipation) of the product simultaneously across the entire product volume without a Delta-T. This enables precise product temperature control, as is required, for example, in bulk polymerization.

The housing, shaft, and discs on the shafts can be heated and cooled. Together, they form an exceptionally large heat exchange surface. This enables precise temperature control—whether to assist in temperature control via speed, to dissipate heat during exothermic reactions and when handling temperature-sensitive materials, or to facilitate the desublimation of a crust-forming product.

The kneading elements force surface renewal and convey the product along the shaft. Without this forced action, the product can also move away from the mixing elements during contact. Only the discharge at the end of the process chamber is carried out by a discharge screw, which provides forced conveyance. Increasing the rotational speed thus enhances the kneading and mixing intensity without shortening the residence time. The residence time is independent of the rotational speed of the kneading reactor’s shaft.

Vacuum tightness down to less than 5 mbara, a large free gas volume in the kneader reactor, and openings with large cross-sectional areas enable the removal of large vapor streams without product carryover, thanks to low gas velocities. Ideal for the gentle removal of large volumes of solvent and efficient residual degassing (devolatilization) of polymer solutions, as well as the production of the purest products.

Kneader reactors are available for both batch and continuous operation. Batch reactors are ideal for R&D involving small quantities, while continuous reactors are designed for efficient industrial processes. This enables scaling through the transfer of R&D results from batch to continuous operation without changing the underlying technology.

The LIST KneaderReactor Technology

Our different LIST Kneader Reactors

Single-Shaft Kneader Reactors

Maximum mixing and evaporation capacity with a high-torque shaft and maximized heat exchange surfaces on the housing, shaft, and shaft discs. The proven solution for maximum throughput and large vapor volumes. Devolatilization, drying, reactions, and polycondensation in the concentrated phase.

Twin-Shaft Kneader Reactors

Maximum self-cleaning and adjustable shear intensity thanks to intermeshing, self-cleaning shafts with different shaft geometries. Ideal for processes with increased requirements for self-cleaning, stickiness, and homogeneity, as well as for various requirements regarding the degree of material protection.

Pilot Kneader Reactor

From feasibility to a validated process concept. Our pilot machines and pilot plants—available at our Technology Centers in Arisdorf (Switzerland) and Gwangju (South Korea) or through our rental program—test feasibility, validate the process concept under real-world conditions, and lay the groundwork for scale-up.

Lab Kneader

Industrial kneader reactor technology on a laboratory scale. Just 1 liter of working volume, but up to 20,000 Pa·s shear viscosity, up to 280°C, and a vacuum down to 5 mbar. Industrial-grade shaft design housed in a fume hood. No process idea should be thwarted by rheological obstacles in the laboratory.

Kneader Reactor Applications Beyond industries and process boundaries

LIST kneader reactors process materials with high efficiency where other machines fail due to rheological challenges: high-performance polymers, synthetic rubbers, superabsorbents, cellulose fibers from recycled textiles, specialty chemicals, active pharmaceutical ingredients, and recycled feedstocks. Twelve process types, over fourteen industries—and the ability to industrially process materials that would not exist without this technology.

All Kneader Reactor Applications

Service Global support throughout the entire lifecycle

A kneading reactor is at the heart of sophisticated production processes. To ensure it operates reliably at the highest level, LIST offers a global service network with locations in Europe, Asia, and North America—available around the clock.

From installation and commissioning to employee training and process support, all the way through to preventive maintenance and spare parts supply: Our service is designed to minimize downtime, extend the service life of your machines, and continuously optimize the performance of your processes.

Learn more about our services

LIST KneaderReactor TechnologyPart of BUSSLIST Group

LIST KneaderReactor Technology is one of three technology platforms within the BUSSLIST Group. Together with BUSS Co-Kneader Technology and BBA Cooling Technology, we cover the entire process chain—from compounding and reacting to cooling and solidification.

This is BUSSLIST Group

More about us

Lyocell 2.0

LIST's process solutions for Lyocell 2.0 enable the efficient conversion of cellulose into high-quality fibres, ensuring consistent material quality.

Physical Recycling

LIST kneading reactor technology enables efficient physical recycling by removing impurities and ensuring consistent polymer quality.

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