| 摘要 |
<p>An improvement is disclosed in a method for producing foamed articles of thermo-plastic or thermosetting compounds. The improvement reduces the number of steps normally followed to make a foamed product and cuts down on the time. The method comprises intensively mixing and thermokinetically heating a particulate composition comprising thermo-plastic resin particles and a foaming agent, the foaming agent having a trigger temperature to initiate gas evolution to effect foaming, the mixing and heating occurring in an enclosed mixing chamber with a plurality of blades attached to arms rotating about an axis, with a blade tip speed of at least about 18 meters per second, continuing the mixing in the enclosed chamber until the composition is heated to a mixing temperature at or above the trigger temperature of the foaming agent, the mixing temperature being sufficient to effect fluxing of the particulate composition to an extent such that the fluxed composition has a viscosity sufficient to contain gas evolved from the foaming agent; discharging the fluxed composition from the mixing chamber when the fluxed composition is at the mixing temperature and when the foaming agent is just beginning to foam; and feeding the discharged fluxed composition to a mold and confining the composition within the mold to mold the composition while foaming of the composition continues, to form a molded foamed plastic article in the mold.</p> |
