METHOD OF DUSTING-PREVENTIVE TREATMENT OF POWDER HAVING DUSTING PROPERTY

• Main Authors: TSUTSUMI, HIROHUMI, URANO, TERUO, SHIMODA, TETSUYA, OGURA, MASATSUNE
• Format: Patent
• Language: English; French; German
• Published: 25.06.2008
• Edition: 7
• Subjects: ADHESIVES; ARTIFICIAL STONE; CEMENTS; CERAMICS; CHEMISTRY; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDINGMATERIALS; CONCRETE; DYES; LIME, MAGNESIA; MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FORELSEWHERE; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; PAINTS; POLISHES; REFRACTORIES; SLAG; TREATMENT OF NATURAL STONE

A method of dusting-preventive treatment in which a powder having dusting property is treated with fibril-forming PTFE (polytetrafluoroethylene) to impart non-dusting property thereto and the non-dusting property 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 polytetrafluoroethylene is added to a powder having dusting property, and a compression/shear force is exerted to the mixture at a temperature in the range of 20 to 200 DEG C to thereby regulate powder so as to have a flow value of 150 mm to 200 mm; and a second dusting-preventive treatment step in which a compression/shear force is exerted again at a temperature in the range of 50 to 150 DEG C, without newly adding fibril-forming polytetrafluoroethylene, to the resultant powder after the powder treated in the first step has deteriorated in dusting-preventive property during transportation with transporting means due to such an external force that the polytetrafluoroethylene fibrils partly cleave or powder particles partly fall off polytetrafluoroethylene fibril nets.