|
|
 |
|
   
|
||||||
|
|
In its developments in equipment and formulations, the business of compounding is keeping step with the demands of innovative plastic products. Also in the mix are the pressures for increased global capabilities in both supply and local manufacturing. Long-fiber thermoplastics In collaboration with Husky Injection Molding Systems, Coperion Corp. has developed technology to complete compounding and injection molding of long fiber-reinforced thermoplastics in one heat. This process replaces the typical plasticizing unit with the ZSK Megacompounder, which prepares the long glass fiber-reinforced melt in an intermittent operation; a plunger generates the pressure required for the injection. Coperion's new ZSK "Megavolume" series, covering a throughput range from 100 to 25,000 lbs/hr, provides substantially higher throughput for processes where volume, not torque, is the limiting factor, such as highly filled compounds. Maximum screw speed was increased to 1800 rpm, resulting in an additional increase in throughput capability. Coperion's newly developed Quantec Buss-Kneader series for compounding rigid or plasticized PVC achieves two to three times the throughput of the previous version with the same machine size. No crammer feeder is necessary for material feeding, and the equipment has low space requirements and is mounted on a common base plate ready for connection. The Quantec series consists of six unit sizes and covers the throughput range of 800 to 33,000 lbs/hr. The Buss- Kneader superimposes a radial mixing effect with the screw rotation and a lengthwise mixing effect caused by the oscillating motion of the screw, creating a high mixing efficiency. ZSK Megavolume twin-screw compounder. Quantec Buss-Kneader. In-line compounding Davis-Standard's most recent compounding advances are seen in inline compounding, where twin-screw extruders are used to create a complex formulation, and extrude it directly into a finished product without the customary interim pelletizing step. The company has supplied complete lines having multiple extruders simultaneously compounding complex formulations, using automation as the essential technology for control of product quality and staff minimization. The in-line concept is suitable for a wide range of processes including sheet, fiber, extrusion coating and extrusions such as pipe, tubing and siding. It is particularly well suited for applications with highly filled products, where letdown from a masterbatch is not applicable. Other advantages of in-line compounding include material cost savings, reduced energy consumption, and minimized heat history for improved physical properties. Improved olefin compound Ferro Corps Filled & Reinforced Plastics Division's newly introduced
line of Gapex-HP glass-reinforced polypropylenes elevates tensile properties,
allowing substitution for nylon in end uses operating below 3000F. The
newest product is Gapex-HT, which increases operating temperatures to
4000F. The olefin alloy molds with extremely tight dimensions and processes
in complex mold configurations. Ferro says the new Gapex products allow
replacing engineering thermoplastics with predictable physical property
tradeoffs, providing selectable performance and "managed economics."
For the appliance and electronics markets, Ferro provides a new line of flame-retarded polypropylenes, including UL 94V-0 products with specific gravities less than one and minimal mold plate-out. Eco- friendly compounds RTP Company has developed new polyester-based non- halogen flame-retardant compounds. Available with glass loadings from 10% to 33%, the PTT (polytrimethylene terephthalate) materials meet European eco-friendly guidelines. The company also recently expanded its line of PermaStat antistatic thermoplastics. PermaStat Plus compounds offer "E-Series" materials with improved electrical properties, and "M-Series," in which the Plus materials feature improvements in flexural and tensile strength compared with older PermaStat compounds. The use of DuPont Fluoroguard synthetic oil has been commercialized by RTP as an alternative to PTFE for wear-resistant compounds. Available in both masterbatch and compounded forms, Fluoroguard has been shown to reduce wear rates in almost all polymers at relatively low loading levels, often below 1%. Additionally, the ingredient functions as a processing aid, acting as a mold release, and eliminates the problematic plate-out effect associated with the use of PTFE additives. Gas injection Leistritz features use of high-torque twin-screw extruders, with splined and hammered screw shafts, for gas-injected foaming. Polymer is fed into the extruder and melted prior to gas injection, and is intimately mixed at high pressures with distributive mixers to minimize viscous heating. The latter part of the process section uses low energy input pumping elements so that the barrel sections serve as a heat exchange device to cool the process melt. A gear pump front- end attachment may or may not be used, depending upon the application. Performing this process in a twin-screw extruder provides an alternative to the traditional tandem single-screw systems. The company has also upgraded its proprietary twin-screw control system to facilitate complete line control. Leistritz ZSE 27 twin-screw extrusion underwater pelletizing system. Non-migrating additives Ampacet Corp. features new nonmigrating slip (product code 101501) and nonmigrating antistat (product code 101710) masterbatches. Product 101501 is recommended for multilayer films where differential coefficient of friction (COF) is desired, since the slip additive is nonmigratory. Acceptable for food contact applications, it can be used at higher temperatures than conventional slip additives. Product 101710 is recommended for multilayer films where preferential functionality is required, such as antistat performance on an inner layer and slip or antiblock performance on an outer layer. Since the additive is nonmigratory, it does not interact with some of the common adhesives used in laminated films, and has no effect on sealing or printing. It is essentially humidity-independent and very thermally stable. Since they typically require higher percentage usage levels than their more conventional counterparts, however, their benefits are expected to be applied in critical applications to justify the higher costs. Soft and clear Teknor Apex has introduced soft and clear grades in its Monprene series of thermoplastic elastomer (TPE) compounds based on styrenic block copolymers. While the new grades are formulated for medical applications, where latex rubber has been widely used because of its outstanding softness, they also provide a high degree of clarity and are readily colored. The new products include grades for medical tubing and film; and the film grades (for drapes, gowns, liners, and gloves) are processable in blown or cast systems. In addition to excellent clarity, hardness levels as low as 30 Shore 00 can be reached. The Teknor Apex Vinyl Division is exploring nonautomotive applications for flexible vinyl compounds in the form of spherical micropellets with diameters of only 0.020 to 0.060 inch-for possible replacement of vinyl plastisols and drysols. The micropellets are based on a standard PVC suspension resin and can be melt-compounded prior to pelletizing. Applications are being explored for trim and skin components of non-automotive vehicles, boots and rainwear, and other slush-molded and rotationally molded products, as well as dip- coated items such as dish racks and hand-tool grips. Monprene TPE film. Steady trends According to LNP Americas, two of the most consistent trends in plastics compounding are "cost downs," or converting away from higher- cost materials; and the need for compounders to manufacture globally. LNP emphasizes that their customers' success is very dependent upon compounders who can transfer their technology seamlessly from one country to another, and not just supply, but also manufacture, compounds that perform consistently in their local applications. The company's latest "cost-- down" technology is its Verton MTX line of long-- glass-fiber polypropylene. Based on Vetrotex America's Twintex technology, these composites allow cost reductions up to 20%, compared to fully compounded long-glass-fiber polypropylene. Verton MTX composites, launched in late 2000, primarily target large industrial, recreational, and automotive components, including instrument panels, door modules, sun roof beams, and motorized cart bodies. Other compounding trends involve "higher value" compounds that upgrade performance, integrate components, increase marketability, or make new technologies possible; and increasing customer-driven emphasis on quality certifications. Plastic-metal composites PolyOne has developed nontraditional compounds like nontoxic, high- density Polymetal thermoplastic-metal composites that are designed to replace lead and other high-gravity metallic materials in radiation shielding and other applications. Another material, Therma-Tech thermally conductive compound, opens up new design possibilities for thermal-management applications, including custom-molded heat sinks on circuit boards. PolyOne is also responding to global changes in regulatory requirements with new materials that offer alternatives in sensitive application areas. In wire and cable, PolyOne's new PlenStar P\VC products for plenum-rated communications cable are low-smoke, flame- retardant formulations, and are fully recyclable. The company has also developed non-lead and heavy metal-free grades for its line of Geon PVC compounds, underscoring its commitment to the environment. Courtesy of PolyOne Corp. Special-effects compounds GE Plastics' development of its Visualfx portfolio of 16 special effects, with the color and effect formulated in the resin pellet, is to a large degree an achievement in precision compounding, aided by application of Six Sigma manufacturing rigor. With the color and effect inherent in the pellet, GE Plastics says, it is able to optimize the level of pigments and additives to avoid an adverse physical breakdown of the polymer that often can occur during the compounding process. Last autumn, GE Plastics launched its newest Visualfx portfolio of effects-Enyo, Lustre, Glass, Make-Up, Smoke, and Frost resins-thus extending the initial Visualfx portfolio launched in 2000. i. Picasso phone from the congruency company, made with GE Plastics' Cycoloy with sparkle effect from the Visualx resin portfolio. Phosphorus- Based FRs High loading requirements and limitations on thermal stability can generally complicate compounding of flame-retardant (FR) additives. Phosphorus-based flame retardants show additional sensitivities in hydrolytic stability and potential of premature interaction with other synergistic components in the formulation. Clariant Corporation has established a set of guidelines, based on empirical data, to complement its varied phosphorus-- based product line for delivery of high-efficiency flame retardancy to thermoplastic materials. Included are Clariant's ammonium polyphosphate (APP)-based intumescent FRs for polyolefins, Exolit AP 750 and Exolit AP 752; red phosphorus, an effective FR for glass-filled polyamides, thermoset resins, and polyolefin wire/cable compounds; and the organo phosphinates, a new class of FR technology consisting of a metal salt of adialkyl phosphinic acid in combination with proprietary nitrogen-containing compounds. Exolit OP 1310 is a development product for polyamides (nylon 6 and 6/6). In contrast to red phosphorus, OP 1013 is a white free-- flowing powder that allows for greater flexibility in color matching and avoids the difficulties of phosphine emissions. Target polymers are polyamides and thermoplastic polyesters. For more information: Copyright Society of Plastics Engineers
compounds compounding plastics plastic resins polymers polyamides thermoplastic polyesters materials PVC flame retardancy additives pigments PTFE additives application Six Sigma manufacturing custom-molded injection molding extrusion plastic-metal composites recreational automotive nonautomotive components glass-fiber polypropylene flexible vinyl thermoplastic elastomer elastomers laminated films masterbatches twin-screw system extruders appliance electronics markets gas injection olefin plasltik plastique plastico compunds process plasticizing |
|
|
|
