Other

Hirofumi Tsutsumi

Tetsuya Shimoda

Teruo Urano

Masatsune Ogura

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&#xb0; 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&#xb0; 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.

Method of dusting-preventive treatment of powder having dusting property

The present invention provides a dusting-inhibited cement composition, which hardly forms dust and further capable of improving strength of concrete or mortar obtained therefrom. A dusting-inhibited cement composition according to the present invention comprises 100 weight parts of cement, 0.01&tilde;0.1 weight parts of fibrillatable polytetrafluoroethylene and 0.001&tilde;1.0 weight parts of alcohol base antifoamer and/or silicone base antifoamer.

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Fukuoka, Japan

Hirofumi Tsutsumi