Abstract: The present invention relates to a packing material used for wrapping an article to be packed and sealing and packing the article to be packed by heat-sealing mutually superposed end parts. The packing material is composed of a biodegradable film. Heat sealing agent layers are selectively provided in the heat sealing positions or the heat-sealed parts of the biodegradable film. The heat sealing agent layers are provided on the front surface and the back surface, the front surface and the front surface, or the back surface and the back surface of the mutually superposed biodegradable film when the article to be packed is packed. On the biodegradable film, picture pattern layers as well as the heat sealing agent layers are formed within a range 70% or less as large as the entire area including the front surface and the back surface of the biodegradable film.

Abstract: The present invention relates to a packing material used for wrapping an article to be packed and sealing and packing the article to be packed by heat-sealing mutually superposed end parts. The packing material is composed of a biodegradable film. Heat sealing agent layers are selectively provided in the heat sealing positions or the heat-sealed parts of the biodegradable film. The heat sealing agent layers are provided on the front surface and the back surface, the front surface and the front surface, or the back surface and the back surface of the mutually superposed biodegradable film when the article to be packed is packed. On the biodegradable film, picture pattern layers as well as the heat sealing agent layers are formed within a range 70% or less as large as the entire area including the front surface and the back surface of the biodegradable film.

Abstract: A magnetic recording medium improved in electromagnetic conversion characteristics and runnability is disclosed. The magnetic recording medium is formed by coating a non-magnetic substrate with a magnetic layer. The magnetic layer contains a fine ferromagnetic powder having a specific surface area larger than 45 m.sup.2 /g, a binder having polar groups such as --SO.sub.3 M and --OSO.sub.3 M in the molecule in an amount of 0.2 to 0.8 .mu.mol per m.sup.2 of the specific surface area of the ferromagnetic powder, and a compound having 2 or more carboxylic groups in an amount of 0.5 to 5.0 .mu.mol per m.sup.2 of the specific surrface of the ferromagnetic powder. The magnetic layer is further incorporated with a carbon powder having a mean diameter of 200 to 400 nm and a specific surface area of 5 to 20 m.sup.2 /g to improve the runnability of the magnetic recording medium while keeping the improved magnetic characteristics.

Abstract: In a tape cassette with a housing including top and bottom walls having respective pairs of spaced apart openings aligned with each other, a pair of hubs disposed rotatably within the housing between the walls and being accessible through the respective aligned openings for selectively driving the hubs of the cassette, and a magnetic tape wound on a cylindrical circumferential surface of an outer peripheral portion of each of the hubs; each of the hubs includes an annular rib radially inward from the outer peripheral portion and projecting axially beyond opposite flanks of the outer peripheral portion of the hub so as to extend rotatably around annular flanges directed axially inward from the respective aligned openings of the housing walls, and a pair of lubricating sheets are disposed against the inner surfaces of the housing walls and each have a pair of ridges or beads projecting therefrom and a pair of holes located between the ridges and through which the annular flanges on the adjacent wall extend with