Broad demand growth expected to continue

Tag : crosslinked wire


To meet demand, machinery builders and polymer makers have come outwith a passel of new technology. For example, wire and cableextrusion equipment maker Maillefer (Ecublens, Switzerland) has anew high-torque extruder, MXC80-24D with ECH12/16 building wirehead, that features the company’s third-generation radial aircooling system. This is said to approach the output of competitiveliquid cooling but without the complexities of water connectionsand maintenance mess. Compared to existing air-cooled machinery,the company claims a 50% efficiency increase.

The unit can be equipped with a dosing system, the Cinegran opticalmaterial control, that debuted at last year’s K show, whichAndre Gosselin, marketing manager at Maillefer, says is a stepabove gravimetric systems. The unit measures material flow in realtime with the aid of a camera. Operator feedback is said to beimmediate. It recognizes most materials except very fine powders,due to their lack of visual contrast, and tacky resins because oftheir uneven flows on the unit’s interior column surface.Depending on the model, the unit has a throughput ranging from100-2000 kg/hr. The company currently also is selling the units forupgrades of their own lines, says Gosselin.

With increased demand for smaller wires to fit into tighter spaces,the company has another novelty, its Micro Wire Extruder line forsolid coaxial cable as small as 90 µm. This unit targetshand-held electronics requiring smaller and lighter wiring. Atcompetitor Reifenhäuser (Troisdorf, Germany), Lothar Staubi,sales manager extrusion center, says the talk among his customerscontinues to come back to how they can save energy costs,particularly in developed markets such as Germany. To help them,Reifenhäuser continues to promote its gearless, direct-drivesingle-screw extruder, REItorque, with screw diameters ranging from25-90 mm and L/D ratios of 25:1 and 30:1.

Staubi says the unit’s screw geometry permits an optimalprocessing of cable sheathings in a range of polymers includingvinyl, polyolefins, thermoplastic elastomers, polyurethane, andnylon without the need for time-consuming screw changes to matchparticular resins.

In the realm of producing cable compounds, Buss says it has decidedthat many of the ‘bells and whistles’ previouslyoffered on modular compounding extruders to make the unitsversatile are not, in today’s market, what compounders aredemanding. With the company’s MX kneader, Buss was able toprovide cost-effectiveness for customers by taking the best ofcertain elements, such as the four-flight screw technology, of thecompany’s already proven Quantec kneader for PVC compounding,says Marco Senoner, corporate communications manager. Without anincrease in size, the MX series provides up to 2.5 times thethroughput and requires about 15% less specific energy compared tothe company’s previous generation. Buss pulled in orders forsix cable compound kneading lines at this spring’s Wire 2008and Chinaplas trade shows.

Materials make it possible

Without the latest developments in polymers and additives, the bestof any wire and cable extrusion equipment won’t have achance. Borealis (Vienna, Austria) has just introduced itssecond-generation Visico FX LE8823 low-density polyethylene (LDPE)for low-voltage cable insulation, which is said to boost thecompetitiveness of cable manufacturers. Available later this year,the grade is said to crosslink at speeds twice that of traditionalVisico grades and typically more than five times that of graftedXLPE materials. Curing under ambient conditions thanks to the useof Ambicat catalysts eliminates an extra production step and cutsthe costs of power needed for hot water baths or saunas, says HansChristian Ambjerg, VP wire/cable at the company. Using this XLPEgrade for insulation in conjunction with a PE jacket permits analmost 50% weight reduction compared to PVC cables, he says.

This first of a family of grades is seen as an alternative toflexible PVC, yet the material is a drop-in for existing vinyl wireand cable extrusion lines. Ambjerg says it offers low-voltage cableproducers, who face increased competition from low-cost offshoresuppliers, with a means to tackle the need for higher productivityat lower costs.

Robert Tarimo, marketing manager at Dow Europe, sees increaseddemand for replacement of high- and extra-high voltage overheadcables with underground systems for security, health, and safetyreasons, as well as for insurance against storm damage that cancause blackouts. The company has introduced a new portfolio ofcleanroom-produced LDPE grades, HFDK4201 SC and EHV for high- andextra-high voltage crosslinked insulation compounds, as well asHFDA0801BK EC and HV for inner and outer semiconductive layers.Other new grades include black and natural ones intended forself-coloring (respectively, DGDK6800 BK and 6862NT) as well asDHDA7708 BK, a semiconductive black PE compound that can be addedinto the jacketing mix to enhance cable integrity testing afterproduction and installation, and during usage.

Spanish-Argentinean plastics supplier Repsol YPF (Madrid) has animproved grade, C220Nexp, offering good mechanical and weatheringproperties at low temperatures for power and telecommunicationsjacketing compounds, says Ana Montenegro, advanced PE productmanager. Ramón Brugada, development programs manager atDuPont Ibérica (Barcelona, Spain), says his company’sHytrel-brand thermoplastic elastomer is a replacement for vinyl orrubber in many demanding wire applications.

As an example, Brugada points to large ethylene-propylenerubber-insulated cables for a lift bridge connecting Minnesota andWisconsin that failed less than two years after entering service.Processor Northwire (Osceola, WI) replaced the defective cableswith Hytrel insulated versions that are more than 40% smaller indiameter than the ones that failed. Brugada says smaller cablediameters provide longer flex life at a given bend radius.