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Carbon dioxide (CO2) can help processors save on cycle times as well as clean molded parts without solvents. Gas giant Linde (Murray Hill, NJ)  will present details on such technologies at the Innovation and Emerging Plastics Technologies Conference to be hosted by Penn State Erie, The Behrend College in Erie, PA, June 18-19.

PlasticsToday Staff

June 12, 2014

2 Min Read
Carbon dioxide boosts plastics' environmental credentials

Carbon dioxide (CO2) can help processors save on cycle times as well as clean molded parts without solvents. Gas giant Linde (Murray Hill, NJ)  will present details on such technologies at the Innovation and Emerging Plastics Technologies Conference to be hosted by Penn State Erie, The Behrend College in Erie, PA, June 18-19.

One such solution is enhanced Gas-Assist Injection Molding (eGAIM), in which the conventional medium of liquid nitrogen (N2) is replaced by cryogenic CO2 to enable injection molders to greatly reduce cycle times. In fact, cooling cycles can often be reduced by more than 50% compared to cycles using N2, and overall cycles can often be reduced by 20-50% according to Linde

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Parts molded with eGAIM (top) and cryogenic CO2 spot cooling (bottom) can slash cycle times.

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"The high efficiency of carbon dioxide, including low investment costs, easy installation and convincing results, make eGAIM very attractive for injection molding for both new molds and for retrofitting existing molds," says Jim Stanley, Linde program manager for the North American plastics industry.

Spot cooling is another technology on offer to reduce cycle times. Linde can help troubleshoot and assist with the engineering of low-cost, CO2 spot-cooling systems to put cryogenics to work on mold hot spots. Precisely engineered CO2 spot-cooling systems can reportedly help substantially reduce the cost of injection-molded parts, or inexpensively add injection-molding capacity without major modifications.

Cryogenic spot cooling helps achieve more uniform cooling across the part geometry, which is critical for injection-molded parts quality, mold-release performance, and reduced cycle times. Linde reports that CO2 spot cooling has been shown in some cases to cut cycle times by up to 50%.

Further, Linde's Cryoclean Snow system is a waterless, solvent-free system for cleaning automotive, plastic and other manufactured parts. The Cryoclean Snow system removes residue and other contaminants from plastic and metal surfaces using a pressurized stream of cryogenic carbon dioxide and micro-particles of dry ice. "CO2 is inert, so there are no ozone-depleting solvents, and no potential for oxidizing metal as with aqueous-based cleaning systems," says Linde.

In addition, Linde will feature the new Presus C system, a liquid carbon-dioxide (LCO2) pressure booster that can reportedly help plastic foam manufacturers and gas-assist injection molders (GAIM) improve efficiency and quality. Designed for precision and long service-life, Presus C systems can supply high-mass-flow LCO2 at a constant high pressure to a variety of industrial processes. Applications include high-performance spot-cooling of hot spots in plastic injection molds, and the supply of bubble-free LCO2 to metering systems such as the Linde DSD 500 for the physical foaming of polystyrene (PS) and low-density polyurethane (PUR).

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