| 摘要 |
<p>A method of dusting-preventive treatment in which a powder having dusting properties is treated with fibril-forming PTFE (polytetrafluoroethylene) to impart non-dusting properties thereto and the non-dusting properties of the powder, after having been reduced during transportation, are economically and advantageously recovered or improved through a relatively simple step. The method comprises: a first dusting-preventive treatment step in which fibril-forming PTFE is added to a powder having dusting properties and a compression/shear force is applied to the mixture at a temperature in the range of 20 to 200°C to thereby regulate the powder so as to have a flow value of 150 to 200 mm; and a second dusting-preventive treatment step in which a compression/shear force is applied again at a temperature in the range of 50 to 150°C, without newly adding fibril-forming PTFE, to the resultant powder after the powder treated in the first step has deteriorated in dusting-preventive property during transportation with a transporting means due to such an external force that the PTFE fibrils partly cleave or the powder particles partly fall off the PTFE fibril nets.</p> |
