Chisso Corporation

Hiromu Sonoda

Taizo Sugihara

Yasuhiko Furukawa

Kiyonori Shiiba

A tobacco filter stock capable of being molded into a filter only be entanglement of filaments with one another without any adhesion means, whereby the resulting filter has a suitable hardness and a superior whiteness. A tobacco filter and a production process thereof are provided, whereby the tobacco filter stock comprises a ton of crystalline polyolefin filaments, preferably crystalline polypropylene filaments, having a single filament denier of 1 to 6 d/f, a total denier of 30,000 to 60,000 D 40 to 60 crimps/25 mm filament, a crimp elastic modulus of 2.5 to 5.0, a frictional coefficient between filaments of 0.20 to 0.37 and a height ratio (height/width) of 0.01 to 0.1.

Tobacco filter stock

A process for producing a highly bulky nonwoven fabric is provided, which process comprises melt-spinning a crystalline propylene polymer as a first component and an ethylene polymer as a second component, into side-by-side or sheath-core type composite fibers so that the first component after melt-spinning can have a specified M.sub.w /M.sub.n value; collecting the fibers into a continuous tow form; stretching the tow in a specified stretch ratio; cooling the stretched tow to a specified temperature and then drawing it by a pair of nip rolls, one or both of which are of a non-metal, to obtain heat-adhesive composite fibers having apparent crimps of a specified number, a specified percentage crimp modulus and substantially no latent crimpability; and heat-treating a web consisting of the fibers alone or a blend thereof with other fibers at a specified temperature.

Process for producing a highly bulky nonwoven fabric

Heat treating a fibrous bundle containing at least 20% by weight of adhesive fibers by introducing the fibrous bundle into a heating zone through an elongated transport zone that is surrounded by said heating zone, imparting heat to the exterior portion of said fibrous bundle by directing heat against the exterior of said transport zone and imparting heat throughout the interior of said fibrous bundle by directing heated gas outwardly through the interior of said transport zone in a direction opposite to the inward movement of said fibrous bundle through said transport zone.

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Shiga-ken, Japan

Hiromu Sonoda