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Feature: Compounding sees growth in niche marketsFeature: Compounding sees growth in niche markets

November 6, 2005

6 Min Read
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The LCM-G series of pelletizing systems from Kobelco Stewart Bolling features gear pump mixing for efficient operation at high shearing rates. Twin-screw designs such as this are often found in compounding equipment today.

An intensive mixer from Kobelco can be configured with a wide variety of rotors?tangential designs from two- to six-wing types, and three- or four-lobe intermeshing designs. Rotor speed can reach 120 rpm in some models.

Large compounding installations, such as this Double Double machine from Davis-Standard, are being designed in modular format to decrease installation time and transportation costs.

A 30-mm twin-screw extruder from CDL Technology is aimed at compounding small quantities for R&D usage. The modular design of CDL twin-screw extruders allows flexibility in screw configuration and process design.

An 83-mm Wellmark twin-screw extruder from CDL Technology for compounding and pelletizing offers a relatively small footprint and high throughput rates.

CDL Technology?s 90-mm twin-screw extruder compounds and pelletizes material. Its compact design includes a tuck-under or rear-drive motor for ease of operation and maintenance.

Kobelco's Nex-T continuous mixer/extruder contains deep intermeshed three-lobe rotor wings for optimal quality material at maximum output speeds.


In addition to higher throughputs, equipment makers focus on modules and specialties.

Not all compounders are alike. Witness the diversity between toll, custom, proprietary, masterbatch, and resin supplier segments in this industry. However, they all share similar goals?reducing time to market and increasing productivity and profit. Without a doubt, compounding machinery is the key element in reaching these targets.

In a recent study, market research firm Freedonia Group (Cleveland) predicts U.S. demand for independently compounded thermoplastics will reach 7.6 billion lb in 2008. This study also calculates today?s domestic independent compounding industry at $10.8 billion.

Driving the growth of compounding is the rise in resin prices and the rise in the cost of developing new grades. By using compounded materials, processors can maximize cost-performance ratios, and resin suppliers can reduce the time and expense of product development. Meanwhile, equipment suppliers are developing and launching systems to meet the increased needs for modular and niche-market gear.

Plant Installations Go Modular

Some of the largest compounding operations belong to major resin suppliers, many of whom are currently building facilities in China to satisfy a growing resin demand. Compounding systems suppliers, in response to this trend, are developing a modular construction approach that aims to simplify transportation and accelerate startup times.

For instance, Coperion Werner & Pfleiderer (Ramsey, NJ) recently launched a modular concept for planning, construction, testing, and delivery of a turnkey compounding plant. In Q1 2006, resin supplier Lanxess (Leverkusen, Germany) will begin operating the first such modular plant at its new site near Shanghai, China. It will compound polyamide (Durethan) and polyester (Pocan).

According to Coperion, the heart of the turnkey plant is the ZSK Mega Compounder Plus, a twin-screw compounding unit designed for a throughput of more than 3000 kg/hr. Upstream of this equipment are feeding and unloading stations for sacks and large bags as well as intermediate containers (also for reprocessing recycled material). Downstream of the compounding machine are operations for pelletizing, classification, pellet cooling, and transferring finished pellets to silos. While the plant is being assembled at the Lanxess Wuxi Chemicals Ltd. site about 120 km northwest of Shanghai, Chinese experts from Coperion sites at Shanghai and Nanjing will work together with the Chinese technicians at Lanxess to minimize language problems.

Modular systems are an idea born out of necessity?long travel distances to China and a growing base of demand there. Coperion says the basic idea is to take functional units of the turnkey plant, designed to customer specifications, combine them into modules, then fully assemble and wire each of these modules in a steel framework. Modules are connected electrically (plug-and-receptacle connectors) and mechanically. Before shipping, the compounding system is set up at Coperion and tested. Upon final customer approval, the modules are simply separated at the interfaces. Steel framework sections are then crated for ocean shipping, sent to the operating site, and reassembled. When mechanical and electrical interfaces are reconnected, the plant is ready for operation. Benefits of a modular approach include:

  • Debugging at the testing stage, rather than in production,

  • No need for intermediate floors because components are anchored to the floors of the steel framework,

  • Ability to produce evaluation samples during the test operation.

    Niche Markets Surge Ahead

    Several specialty applications are making waves in the compounding universe these days. Wood-fiber composites, for one, require high-end mixing and dispersion with precise temperature control. Inline compounding systems, an almost exclusively automotive development, are on the rise. Color masterbatch compounding, another growing area, requires consistent, repeatable, and quantifiable results.

    Equipment manufacturers are responding to these growing segments with new products tailored to their needs. For example, Davis-Standard (Pawcatuck, CT) introduced its KXE FPV-pump with an eye toward color compounders. Spokesman Simon Dominey explains that the pump improves quality control testing by providing accurate and repeatable pressure control. ?The pump is an essential tool for compounders, especially color compounders, as it provides a filter-pressure value to quantify the level of resin dispersibility. The FPV helps compounders maintain product consistency and provides a standardized, globally-recognized method of comparing one product to another?one that?s more repeatable than the less quantifiable ASTM system previously used.?

    Davis-Standard?s FPV-pump is available as an integrated component on a new laboratory extrusion system or as a stand-alone unit for attachment to an existing extruder. Marketed by Davis-Standard?s Killion business group, it combines a standard 1-inch extruder with a melt pump, two pressure sensors, filter screen, control panel, and display to test how well a color masterbatch disperses in a compound. A computer is needed to plot the pressure changes.

    ?The FPV-pump tests masterbatches against the new European DIN and EN39000 standards that are required for many global compounds,? Dominey says. Killion also offers an automated camera-based gel and black-spec inspection system.

    Wood-fiber composites and associated wood-flour compounds are also on the rise, and several manufacturers offer systems that can be successfully used with these materials. Coperion reports that one of its Swedish clients specializing in wood-fiber composites recently signed a contract with a Swedish furniture manufacturer that operates throughout Europe to supply material for injection molding. A ZSK Megavolume unit will produce the compounds.

    These materials require optimum mixing and dispersion, extremely short residence time, and the ability to control melt temperature to avoid ?burning? the wood component. Farrel (Ansonia, CT) offers its Ultima Compounder for this application, because mixing and extruding functions are separated for the lowest polymer mixing temperatures allowable. Kobelco Steward Bolling (Hudson, OH) touts its Nex-T continuous mixer/extruder with intermeshed three lobe rotors. Krauss-Maffei (Florence, KY) has also developed a wood-filled composite system with a pair of tandem corotating twin-screw extruders.

    Inline compounding for long-fiber thermoplastics is another growth category for compounders. According to Coperion, the technique of reinforcing plastics with glass or natural fibers up to 100 mm in length is now in a dynamic growth phase. The company says that production of long-fiber-reinforced compounds has more than tripled in the last 10 years due to the cost-effectiveness and high flexibility of this process for the automotive and transportation industry, which accounts for about 95% of all applications. Manufacturers offering direct or inline compounding systems include Coperion, Krauss-Maffei, and Composite Products Inc. (Winona, MN).

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