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The machine and plant manufactur-ers offer versatile and powerful com-pounding systems. In order to meetgrowing demands for economy, en-ergy-efficient and flexible systemsare particularly in demand. Shortercleaning and setup times lead to in-creased flexibility and installationavailability. Also concepts for in-creasing the flow contribute to thecost of the treatment process. At thesame time, the efficient use of rawmaterials is increasingly important.As a result, low power consumptionand high productivity and flexibilityplay a major role in recycling, too.

Coperion

Optimized FeedCoperion GmbH, Stuttgart, Germany,have boosted the throughput of theirtwin-screw extruders with its innova-tive feed enhancement technology(FET). A vacuum applied to a porous,gas-permeable wall section in thefeeding zone sucks moisture and airout of the feed material. This com-pacting of the loose material doublesor trebles the material feeding capac-ity. The optimized feeding zone can befitted to both the ZSK twin-screw ex-truder and the ZS-B twin-screw sidefeeder. Borealis AG, Vienna, Austria,has already successfully used thisnew technology in the production oftalcum-filled compounds in pilotplants at its Innovation Headquartersin Linz, Austria. Plastic melts can bedegassed with the ZS-EC twin-screwside degassing unit. The side de-

gassing unit can be retrofitted to ex-isting machines and the standardmodels are designed for an absolutevacuum of 50 mbar. Lower degassingpressures are available on request.The UG 1250 underwater pelletizer iscapable of processing more than100 t/h of polyethylene. The die platehas a mean cutting diameter and con-tains up to 11,000 die holes. The UGis wear-protected and has hydrauliccontrols. It allows water flow rates ofup to 1,500 m2/h. The Coperion UG 750also delivers a solution that is specif-ically designed for pelletizing thermo-plastic elastomers (TPE). The opti-mized water flow avoids turbulenceand prevents collisions between cut,sticky TPE pellets. When it comes topolyolefin processing, the MP 450polyolefin melt pump (Fig. 1) can man-age up to 65 t/h. The involute gears ofthe melt pump run on hydrodynamicplain bearings, lubricated by the poly-mer melt. The process-dependent de-sign factors of the melt pumps are cal-culated and specified for each prod-uct and project.V Hall 14, booth B33

Brabender

Compounding on a LaboratoryScaleWith its Plasti-Corder BrabenderLab-Station and Lab-Station ECtorque rheometers, BrabenderGmbH & Co. KG, Duisburg, Germany,offers flexible compounding systemson a laboratory scale. Both torquerheometers, in combination with theuniversal docking station, canoperate kneaders and single-screw and twin-screw extrud-ers. While the Plasti-CorderLab-Station, rated at 16 kW, isdesigned for speeds rangingfrom 0.2 to 350 min-1 and a max-imum torque of 400 Nm, thePlasti-Corder Lab-Station EC isconfigured for lower speedranges. By virtue of theirmodularity, the Plasti-CorderLab-Station and Lab-StationEC allow the operation of small sin-gle-screw extruders, conical twin-screw extruders and laboratory

SPEC I A L K 20 10 Compound ing , Re c y c l ing

© Carl Hanser Verlag, Munich Kunststoffe international 9/2010

COMPOUNDING, RECYCLING. Compounding engineering focuses on rendering the

compounding process more economical. Various approaches are presented for

improving the economics, such as the use of more energy-efficient equipment,

greater system availability and enhanced throughput.

Efficiency as Benchmarkkneaders. Larger single-screw ex-truders and kneaders and co-rotat-ing twin-screw extruders can beused with the Plasti-Corder Lab-Sta-tion. In addition to the Plasti-CorderLab-Station series, the BrabenderPlastograph is a benchtop version ofa torque rheometer which acts as ameasuring drive for small single-screw extruders, conical twin-screwextruders and small laboratorykneaders. Additionally, in the KEDSE12/36 and KEDSE 20/40 lab com-pounders (Fig. 2), Brabender hasadded two new compact, miniaturetwin-screw extruders with screw di-ameters of 12 and 20 mm and bar-rel lengths of 36 D and 40 D to itsproduct portfolio. Both processingunits have a tiltable barrel which en-ables the compounding steps to beassessed visually. Screw removaland barrel cleaning are also easieras a result. By virtue of the screws’modularity and themetering andventing ports, theselaboratory extrud-ers offer the

Fig. 1. MP 450 melt pump with a throughput for polyolefins of 65 t/h (photo: Coperion)

Translated from Kunststoffe 9/2010,pp. 68–76. Article as PDF-File at www.kunststoffe-international.com;Document Number: PE110513

Fig. 2. LaboratoryKEDSE 20/40 twin-screwextruder (photo: Brabender)

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standard features of twin-screw ex-truders. The laboratory extruders areof particular interest to the plasticsand pharmaceutical industries in theprocessing of tiny quantities of R&Dmaterials.V Hall 10, booth A22

KraussMaffei Berstorff

Energy-efficientCompoundingKraussMaffei Berstorff GmbH,Hanover, Germany, offers a modularcompounding installation which fea-tures various measures to increaseenergy efficiency and reduce setupand cleaning times. Studies byKraussMaffei Berstorff show thatusing a large extruder at mediumspeed can save more energy thanoperating a small extruder at highspeed. The compounder installationtherefore features a ZE 60 A UTXtwin-screw extruder (Fig. 3). Theextruder has a maximum speed of600 min-1. The powertrain and ex-truder heating system have been op-timized to further boost energy effi-ciency. Using a larger extruder atlower speeds generates a larger freevolume in the processing section.This reduces mechanical stress onthe material and wear on screw andbarrel elements. To shorten setupand cleaning times during a productchange, KraussMaffei Berstorff of-fers the entire compounding instal-lation in an “EasyClean” design.Feed hoppers, material conduitslines to the metering devices and si-los, and other connections are con-nected with clamp joints andclamped flange connections and can

be loosened without tools. Specialsealing profiles ensure reliabletightness during the productionprocess. For frequent productchanges, a Mixomat can also beused. This device combines com-pounding functions such as convey-ing, weighing and mixing and fea-tures a large cleaning opening. A fur-ther component of the compounderis the central dust extraction system.V Hall 15, booth C24

Buss AG, Pratteln, Switzerland, has de-livered the world’s largest compounderfor the production of PVC cable com-pounds to Kabelbedrijven Draka Ned-erland BV, Emmen, Netherlands(Fig. 5). Maximum throughput variesfrom 4,500 to 5,000 kg/h according toformulation. The compounder canprocess eight different formulationswith minimal product changeovertimes and with no modification outlay.It features a heater-cooler pre-mixerand gravimetric feeding into the high-performance mixer. The four-flight

quantec 110 EV co-kneader has akneader shaft diameter of 110 mm anda processing length of 15 D. The en-larged intake zone of the co-kneaderaccommodates even the largest fillervolumes. The configuration of the mix-ing and kneading screw ensures ho-mogeneous mixing of the material. Af-ter mixing, the PVC compound is trans-ferred to a single-screw melt extruderwhich generates the pressure for sub-sequent pelletization. This is followedeither by dry or water-mist pelletizing.V Hall 16, booth A59

Fig. 4. The dual-shaft Pegasus mixer leads to energy savings (photo: Dinnissen)

Fig. 3. The ZE 60 A UTX twin-screw extruder is equipped with

active and passive measures to increase energyefficiency (photo: KraussMaffei Berstorff)

Fig. 5. Installation for the production of PVC cable compounds (photo: Buss)

So that plastics processors can perform a simple change of color and ingredients, Dinnissen BV, Sevenum, Netherlands,has developed the hygienic compact containment concept. This enables product changes to be made without the needfor costly cleaning of the entire process line. The mixing systems are cleaned fully automatically with compressed airprovided by compressed air tanks. An interval switch for the cleaning air ensures that the individual components arecleaned in the proper sequence. Another advantage of this dry cleaning concept is that powdered materials do notclump or caking. The mixers are readily accessible and support fast and thorough cleaning. The entire mixing systemis designed to be dust-free. This concept shortens cleaning times during product changes. In addition, the combinationof dual-shaft Pegasus mixer (Fig. 4) and an energy control program has been optimized for further energy savings.V Hall 10, booth B26

Dinnissen

Rapid Material Change

Buss

Cable Compounds as a Reference

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Fig. 6. Laboratoryunderwater pel-letizer conceivedfor materialdevelopment andcapable ofthroughputsranging from 1 to 100 kg/h (photo: Econ)

technology. In addition, 3S, a sub-sidiary of Erema, offers laser-clad ar-mored screws up to 6 m long andscrew diameters of 50 to 500 mm.The Lasex method employedachieves hardness values of 57 HRC.Furthermore, at K2010, 3S will pres-ent wear-resistant barrels for conicaltwin-screw extruders, along with anew wear-measurement system.V Hall 9, booth C05

Hellweg

Small LumpGranulatorFor small start-up lumps, HellwegMaschinenbau GmbH & Co. KG,Roetgen, Germany, offers a smalllump granulator for single-stageshredding. A particular feature of thegranulator is that the material ispeeled off the start-up lump, and soblocking of the rotor prevented(Fig. 9). The rotor has four blades thatcan be used on both sides and re-sharpened many times. The rotor hasa diameter of 260 mm and an effec-tive width of 240 mm. As a result, giv-en a screen hole diameter of 5 to12 mm and a drive power of 15 kW,

In its EUP 50 (Fig. 6), Econ GmbH, Traun, Austria, has developed a new labo-ratory underwater pelletizer. The pelletizer boasts integrated die-plate ther-mal insulation for easy handling, product diversity and good product quality.The pelletizer’s compact centrifugal dryer can be cleaned in a few minutes.The pelletizer can be used to pelletize all thermoplastics, and elastomers andsilicones. It has a throughput of 1 to 100 kg/h and is thus ideal for material de-velopments, particularly in the plastics industry. The underwater pelletizer al-so lends itself to frequent material or color changes, such as the productionof small amounts, e.g. in compounding and masterbatch operations.V Hall 9, booth C55

Econ

Pelletizing for the Lab

Gneuss

All-in-One System for PET Waste

ciency. The multi-screw drum hasnow been certified by the U.S. Foodand Drug Administration for com-pounding post-consumer goodsto regrind for food contact. Addi-tionally, the filter area of the RSFgenius melt filter modelshas been increased by op-timizing the melt chan-nels. As a result, it willbe possible in the futureto use the next-smallerfilter model, without sacri-ficing extrusion perform-ance. Together with animproved heater design,the overall outcome is anenergy-efficient filtrationsystem.V Hall 9, booth A38

An upgrade to the TVE extrusion sys-tem of the Erema TVEplus recyclingline from Erema Engineering Recy-cling Maschinen and Anlagen GmbH,Ansfelden/Linz, Austria, makes formore efficient and economical recy-cling of plastics, says the manufac-turer. The recycling installations fea-ture the usual material flow: Mater-ial is conveyed to the installation ona conveyor belt and is then shreddedand transferred to the compoundingextruder. Before the extrudate is dis-charged, the melt is degassed and fil-tered. The extrudate can then be pel-letized and dried. Melt filters are nowplaced ahead of the degassing sys-tem, with an interposed mixing sec-tion, and this arrangement allowseven difficult waste materials, suchas multi-layer and printed packagingfilms, to be pelletized. A compactcrystallizer developed for the Vac-urema technology (Fig. 8) keeps theacetaldehyde content of PET pelletsbelow 1 ppm. Consequently, recycledPET bottle flakes compounded usingVacurema technology can be ap-proved for renewed contact withfood. To reduce energy demand, Ere-ma recycling installations can beequipped with the new ecoSAVE

Fig. 8. Compact in-line crystallizerwith a Vacurema for compounding

bottle regrind (photo: Erema)

Fig. 7. Multi-rotation system extruderfor direct recycling of PET fiber or

film scrap (photo: Gneuss)

Back at K2007, Gneuss Kunst-stofftechnik GmbH, Bad Oeynhausen,Germany, presented the multi-rota-tion system (MRS). The systemserves in conjunction with a cutter-feeder combination, the RSFgeniusfiltration system and the VIS onlineviscometer as the first all-in-one sys-tem for direct recycling of PET fiberand film scrap. The installation has athroughput of 500 to 700 kg/h. ThePET can be processed economically,without pre-drying. The MRS extrud-er (Fig. 7) is a single-screw extruder,whose middle section is equipped

with a rotating drum. Arranged alongthe axis of rotation inside the drumare eight barrel bores with recessedscrew conveyors. The screw convey-ors rotate counter to the direction ofthe drum and are driven by a gearring. To ensure that melt flows intothe barrels, their outer region isopened some 30 %. Advantages ofthis system include simple tempera-ture control of the drum, and the largesurface area, which makes it possi-ble to achieve a high degassing effi-

Erema

Progress in PET Recycling

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>

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throughput rates of 80 to 180 kg/h areachieved. The granulator is suitablefor polyolefins and many engi-neering plastics. The regrind ishomogeneous and has alow dust content.V Hall 11, booth B39

A melt filter for the direct manufac-ture of PET fibers, films and packag-ing tape will be presented by Kreyen-borg GmbH, Münster, Germany, withits K-SWE-4K/75 RS. This filter offersa large filtration area with continuousprocessing. It is thus suitable for com-pounding processes involving highcontaminant levels and high processengineering requirements. In the fieldpelletization, the wear protection ofthe underwater pelletizer of Bruck-

mann Kreyenborg GranuliertechnikGmbH, Münster, has been improved.Wear costs, especially in the pelleti-zation of glass fiber-reinforced com-pounds, can be reduced through theuse of wear-protected blades and thespecially coated die plate. In addition,installation availability is increased

due to quick-change wear sleeves inthe water box and in the pelletizer’sinlet and outlet. The rotor of the down-stream dryer, too, no longer needs tobe totally replaced when worn, be-cause individual components can bereplaced. The pelletizer’s automaticmode of operation also eliminatesstrand breaks that occur in brittle ma-terials. A larger version of the pel-letizer can be used for pelletizing EPSmicro pellets. Kreyenborg Plant Tech-

nology GmbH Co. & KG, Senden, Ger-many, will be exhibiting a newly de-veloped, discontinuous infrared rotarykiln (Fig. 11). The rotary kiln utilizesshort-wave infrared radiation and isparticularly suitable for drying andcrystallizing masterbatches.V Hall 9, booth A44, A48 and A55

Fig. 9. Lump granulator for shredding start-up lumps (photo: Hellweg)

By using stuffing screws, Herbold Meckesheim GmbH, Meckesheim, Germany,can force-feed the granulators in its SB series. This increases the throughputof the granulator and saves on energy (Fig. 10). HB series granulators are usedfor shredding whole bales of film, foamed plastics and injection molded andblow molded parts in a single step. For highly contaminated plastic waste,such as agricultural film, Herbold has developed the HGM wet shredder. This

reduces the wear problems that beset agricultural-film cleaning installationsand increases their efficiency. The Herbold product portfolio further includesa “plastcompactor” for producing free-flowing agglomerates, and newly de-veloped pulverizers.V Hall 9, booth B42

Herbold

Saving Energy while Shredding

Fig. 10. Energy-saving concept (photo: Herbold)

Fig. 11. Infrared rotary kiln for batch drying and crystallization (photo: Kreyen-

borg Plant Technology)

Rodent Recycling

Energy-Saving NewcomerRodent Recycling Machinery GmbH, Pucking, Austria, was founded in 2009and is a member of KUAG Group, Pucking. Recycling installations from RodentRecycling offer lower energy consumption due to a rethink of the cutting geom-etry in the shredder, the optimized screw and improved material feeding. Theinstallation’s water-cooled die face pelletizer has also been optimized, so thateven materials with high MFR values can be processed. Subsequent drying isperformed by a dryer, without centrifuge.V Hall 9, booth D73

Kreyenborg

Optimized Wear Protection

M-A-S

Extruder with Direct DriveConstant maximum torque across theentire speed range can be achievedwith the conical co-rotating twin-screw extruders of Maschinen undAnlagenbau Schulz GmbH (M-A-S),Pucking, Austria, thanks to a torque

drive (Fig. 12). The rugged design al-lows the extruder to be coupled di-rectly to the distributor drive, creat-ing a closed and torque-rigid powerflow. Monitoring the torque with adrive-control unit that switches off

Fig. 12. Co-rotating twin-screw extruder with fitted torque drive (photo: M-A-S)

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when overloaded eliminates the needfor a coupling. The new drive conceptyields a more energy-efficient ex-truder, which is especially attractivefor the processing and recycling ofpolyethylene terephthalate(PET) and polyolefins and thecompounding of wood plasticcompounds and materials withlow bulk density that must betreated gently.V Hall 9, booth B56

Weima

ModularShredder SystemsThe modular shredder system fromWeima Maschinenbau GmbH, Ilsfeld,Germany, is ideal for shredding start-up lumps, films and hollow bodies.Special ram systems are available asappropriate for start-up lumps, filmsand hollow bodies. Since the ram sys-tems ensure easy access to the cut-ting system, quick cleaning and main-tenance are possible. The cutting sys-tem features a rotor and various sizesand shape of knives.V Hall 9, booth A59

At two booths, Starlinger & Co.GmbH, Vienna, Austria, will displaytheir recycling installations. The re-coSTAR universal 65 VAC installationboasts a newly developed feed sys-tem. In particular, film, fibers, fabricsand nonwovens can now be recycledwith greater reliability and at higherrates. The recoStar PET installationscan now recycle PET at a rate of 3,600kg/h. Also available is a 15,000-literreactor for increasing the intrinsicviscosity and de-contaminationby the so-called

solid-state polycondensation princi-ple. Polyolefins, engineering plastics,foamed materials, or PET bottleflakes can be recycled and processeddirectly by connecting the recyclinginstallation directly to a film extrud-er (Fig. 14). Thanks to this innovativein-line solution, for example, pack-aging film for food contact can bemade from PET bottle flakes.V Hall 9, booth D21,

Hall 16, booth B47

Uth

Fine-meshingStrainers in the MixingLineTo enhance the product quality andeconomics of rubber, silicone and tiremanufacture, Uth GmbH, Fulda, Ger-many, offers innovative fine-meshstraining of finished blends in themixing line. Where blends are fre-quently changed, the roll-ex series ofextruders can be cleaned quickly andthoroughly. Thanks to its modular de-sign, the roll-ex system can be com-bined with two-roll feeder, a single-screw extruder or a conical twin-screw extruder. Standard throughputrates range from 70 to 6,000 kg/h.V Hall 15, booth D41

Scheer

Under a NewBannerC. F. Scheer & Cie GmbH & Co. KG,Stuttgart, Germany, will be present-ing itself for the first time under thenew company name of Reduction En-gineering GmbH. Its expanded prod-

uct portfolio contains new develop-ments in the field of strand pelleti-zation (Fig. 16) and an underwaterpelletizer of in-house design with athermally insulated die plate. Alsoavailable are energy-saving powdermills as compact, all-in-one systemswith pellet metering, conveying sys-tem and classifiers.V Hall 9, booth E37

Fig. 16. This strand pelletizer is offered by Reduction Engineerng, the newname for Scheer (photo: Reduction Engineering)

Fig. 14. recoStar basic inline recycling solution(photo: Starlinger)

Nuga

Preliminary Shredding with One ScrewAdding to its patented CentriCut cutting mill concept, Nuga AG Kunststoff-

schneidmühlen, Balgach, Switzerland, has de-veloped the ConCut single-screw pre-shred-der (Fig. 13). The single-screw pre-shredder

was developed as a flexible solution forshredding, e.g., bulky parts, start-

up lumps, including hot lumpsdirectly at the production

site for in-line recycling, aswell as for shredding fibers

and films, either as astand-alone

solution or in combination with cutting mills fortwo-stage shredding.

Throughput rates are up to 1,500 kg per hour, depending on the size, in-stalled power capacity of 11 kW to 30 kW max. and the input material to beprocessed. The hopper and rotor are designed specifically to dovetail with eachother for optimum feeding of the material without the need for stuffing de-vices. V Hall 9, booth B11

Fig. 13. ConCut in com-bination with a CentriCut cutting mill for two-stageshredding (photo: Nuga)

Starlinger

From PET Bottle Flakes to Film

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Compound ing , Re c y c l i ng SPEC I A L

Conclusion

For machinery and equipment mak-ers, the emphasis is on improvingefficiency. To this end, they haveadopted different approaches. Inno-vations are primarily to be found inthe field of energy efficiency. Otherapproaches aim for greater plantavailability or increased throughputrates. �

Florian Puch, Aachen, Germany

Entex

Planetary Roller Extruder forElastomer CompoundsEntex Rust & Mitschke GmbH, Bochum, Germany, has designed a planetaryroller extruder (Fig. 17) for compounding elastomers. Unlike the batch process,planetary roller extruders yield homogeneous elastomer compounds combinedwith a self-cleaning effect and precise temperature control. To this end, theextruder is composed of four rollers in series with a total processing length of5,600 mm and a pitch circle diameter of 400 mm. An increased toothing widthreduces wear and improves service life. In order that the compact installationmay achieve throughputs of 6,000 kg/h, it comes with a 1,000-kW motor withappropriate gearing.V Hall 16, booth A42

Fig. 17. Planetary roller extruder for elastomer compounds (photo: Entex Rust & Mitschke)

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