Highlights from this year’s NPE show

NYLON INNOVATION ENHANCES PROCESSING AND PERFORMANCE

Using a proprietary polymerization and patented compounding technology, Rhodia Engineering Plastics has developed a new type of nylon with improved flow characteristics, which in turn will provide designers and processors with better processing and performance characteristics, the company says.

Called TechnylStar, the nylon is produced using special catalysts and chemicals in the polymerization cycle, which creates a semi-crystalline, non-linear polymer with a lower viscosity, according to a company spokesman. Laboratory tests confirm at least 50 percent improvement in spiral flow tests in comparison to other grades of nylon.

High-flow grades of TechnylStar can be reinforced to levels of up to 65 percent and still provide superior quality molded surface finish. Rhodia expects heavily reinforced grades to compete with high performance polymers such as polyarylamide, polyphenylene sulfide (PPS), light alloys and polyphthalamide. Additionally, the company says, TechnylStar is processable at lower clamp forces, allowing a smaller size of injection machine to be utilized, or providing the opportunity for increasing the number of mold cavities.

The new nylon is produced in Poland and is being compounded at the company’s Mississauga, Ont. compounding facility. The first commercial application for TechnylStar is a ski binding; as well Rhodia says it is close to obtaining a commercial automotive application for the resin in Europe.

MICROCELLULAR FOAMING PROCESS REDUCES MATERIAL IN BLOW-MOLDED BOTTLES

Trexell Inc. announced the completion of a successful development program with a leading bottle end-user which utilized the company’s proprietary MuCell blow molding technology to make light-weight bottles from HDPE.

According to Richard Straff, a vice-president at Trexel, the project has demonstrated that MuCell bottle manufacturing is compatible with the high production rates on a wheel-type machine. Straff says that MuCell bottles made from continuous high-speed extrusion exhibited a material reduction of 20 percent while maintaining important physical attributes such as stiffness. Trexel has completed a retrofit design for a wheel machine in order to confirm that cost and performance objectives can be met.

The MuCell process uses supercritical fluids of atmospheric gases to create microscopic cells throughout thermoplastic polymers, thereby reducing material usage and improving productivity.

Trexell plans to target the technology for large-volume wheel machines, which are typical of those used by leading bottle converters.

MACHINE FIRST TO COMBINE ALL-ELECTRIC, TIEBARLESS BENEFITS

Engel’s Electric Tiebarless machine, featuring five servo-electric axes which drive both the injection and clamp units, was demonstrated running a typical high-precision, clean-room application: a 64-cavity pipette mold mounted on an extended platen.

The machine is the first to combine the advantages of an all-electric machine — speed, precision, clean operation and quieter operation — with the benefits of tiebarless machine construction — greater usable platen area, freer access to the mold, easier mold changes and better molding economics.

Calling it the next logical step in the evolution of machine technology, Engel says the machine approaches the ideal for high-precision applications, incorporating the proven platen parallelism and centricity of the Engel Tiebarless.

“Until now, tiebarless and electric machines have been competing for essentially the same market,” says Kurt Fenske, vice-president sales and marketing. “For customers it was frustrating because to get one, you had to forego the other.”

The initial line-up of the new Engel Electric Tiebarless will be available early in 2001 in clamp tonnages of 60, 110 and 165 tons.

HOLLOW-PRODUCT MOLDING TECHNOLOGY DEBUTS

JSW Plastics Machinery’s new J-200 EL II Electric Servo Drive molding machine incorporates the Die Slide Injection Molding System which makes it possible to produce completely closed hollow products.

Typically, hollow products are produced by methods that include gas injection, blow molding, “lost core” or some secondary process such as bonding. JSW’s Die Slide Injection Molding System uses molds that have one half fixed to the machine’s movable platen. The other half of the mold has an element fixed to the stationary platen. In between them is the movable slide mold, driven by a hydraulic cylinder. One mold has a separate cavity and core of the product to be molded. The slide mold is constructed as a mirror image of the other half. Plastic is injected into the cavities to form separate halves of the product. The mold is then opened and the die slide hydraulic mechanism moves the slide mold so each half of the part is opposite each other. The mold is then closed to join the separate, semi-molded halves into a finished product.

JSW says the technology is capable of producing hollow products with uniform and accurate wall thickness. Secondary operations can be eliminated; as well, products with internal ribs and bosses can be produced.

CANADIAN-DESIGNED PELLETIZER EVEN HANDLES POLYPROPYLENE

A small, versatile underwater pelletizing system that generated a lot of interest at Farrel’s NPE booth was developed in conjunction with a Canadian company. TDS Technologies Inc. designed the pelletizer with input from Farrel, and manufactures the units at the TDS plant in Delta, B.C. Farrel has responsibility for marketing the pelletizers.

TDS president Kelly Ready says the Hydron pelletizer is suitable for many resins, including polypropylene, which other units of this size are not able to pelletize. Farrel’s Mike Hotchkiss explains that the benefits of the Hydron pelletizer are due to the heating technology for the die plate. A combination of coil and rod heaters near the die holes provide the most concentrated die heating system yet developed, reports Farrel.

CONDUCTIVITY ENHANCED WITH CARBON NANOTUBES

RTP Company has introduced a family of specialty conductive thermoplastic compounds based on hollow carbon nanotubes, structures thousands of times smaller than carbon fibers. Nanotube compounds (NTCs) are said to deliver uniform and precise surface resistivity throughout a resistivity spectrum ranging from ESD to strong anti-static-typically 104 to 109 ohms/sq. in.

The nano-scale size of the carbon tubes achieves a high aspect ratio, providing conductive properties at very low loadings. To obtain similar conductivity using traditional additives such as carbon fibre or carbon black requires higher loadings that may affect properties such as strength and impact, processing and surface finish.

RTP, the first company to commercialize inherently conductive compounds, says NTCs are ideally suited for wafer processing, disk-drive components and clean room applications. They provide static discharge protection in applications such as automotive fuel system components. The conductivity of NTCs also make them suited for electrostatic painting of automotive interior and exterior parts without using a conductive primer.

NTCs are currently available in polyolefins, nylons, polycarbonate/ABS, polystyrene, polycarbonate, PBT and other engineering resins.

INCREASE PROFILE EXTRUSION LINE SPEED WITH NITROGEN GAS COOLING

Conair and Material Enhancement Technology Inc. have joined forces to develop and manufacture a nitrogen gas cooling process for plastic extrusion that has the potential to dramatically increase line speeds while using much less floor space than existing water-based cooling processes.

Nitrogen gas cooling units have been used successfully to replace or augment water-based cooling in a number of real-world applications over the last year. According to Conair, processors who replaced all sizing and cooling equipment with nitrogen gas cooling technology reported line speed increases of 90 to 200 percent and a tremendous reduction in required floor space.

In many applications, the nitrogen gas cooling system will have several
zones, each with its own temperature controller to maintain the temperature of the gas within 1 F of setpoint. High-velocity blowers circulate the gas around the hot extrusion at rates up to 2000 cfm.

Gas cooling does not affect material properties of the plastic, and the process is compatible with existing extrusion lines.