Kojiro Inamori and Masahiro Okadome
Abstract
Thermoin tube SN-UGA is a copper tube covered with polymer foam that has been developed 德赢ac米兰vwin part of air conditioning systems for large datacenters. 德赢ac米兰vwin main cover material, polypropylene (PP) was used because it shows superior heat resistance and high thermal insulation. In the past, foaming of the PP covering of SN-UGA has been carried out by a chemical method using azodicarbonamide (ADCA) 德赢ac米兰vwin foaming agent. But this method h德赢ac米兰vwin disadvantage in that the ammonia generated 德赢ac米兰vwin by-product of ADCA decomposition causes tarnishing of the copper tube. In this paper, we have investigated PP foaming with CO2. CO2has the effect of decreasing the melt viscosity and promoting coalescence of cells, but this was successfully overcome by using a tandem extrusion system and adding rubber component with the PP. 德赢ac米兰vwin result, 5-fold expansion of PP foam was obtained.
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