CO2 as physical blowing agent cuts costs in PUR foaming

23-Jul-09

There is a steady trend towards using CO2 as the physical blowing agent in flexible foam production. CO2 nucleation is already being used successfully in series production of back-foamed carpets. CO2 is also increasingly the option of choice in producing flexible foam seat elements for the automotive and furniture industries. KraussMaffei supplies reliable and cost-effective systems for mass-flow regulated CO2 nucleation. CO2 has a number of technical and cost advantages as a physical blowing agent for PUR. Its high solubility means that it mixes very homogenously with the PUR components. As a nucleation agent, it improves the mixing quality. CO2 reduces urea formation, resulting in fewer hard segments in the flexible foam. Using CO2 produces low-density flexible foams with outstanding mechanical properties. CO2 is a low-cost, environment-friendly blowing agent and it’s available in virtually unlimited quantities. Foaming systems that currently operate with conventional blowing agents can be easily retrofitted to use CO2 and deliver the same benefits. KraussMaffei CO2 nucleation units can be integrated quickly and with minimal effort. The simplest solution – recommended for extremely low to medium CO2 concentrations – is a batch system that is linked directly to a day tank. For applications requiring very high CO2 concentrations, KraussMaffei offers batch systems where nucleation takes place in a buffer tank. The third approach is an online system where the CO2 is metered in at the mixing head. This variant allows CO2 concentrations to be varied from shot to shot. In all three variants, CO2 metering is mass-flow regulated, in other words, the concentration of CO2 in the PUR components is not affected by pressure or temperature. The process is engineered to ensure that the gas dissolves completely in the PUR component. KraussMaffei expertise and trials in the company’s test lab will help to determine which variant is best-suited for a specific application. In addition, KraussMaffei makes loan equipment available, so that processors can try out the benefits of CO2 nucleation before coming to an investment decision.