Bicomponent fibers and tobacco smoke filters formed therefrom

A method of making tobacco smoke filter means comprising:

• a) providing separate sources of a molten core-forming thermoplastic material and a molten sheath-forming material selected from the group consisting of cellulose acetate, copolymers of vinyl acetate and at least one other monomer, and totally and partially hydrolyzed products of said copolymers;
• b ) continuously extruding said molten core-forming and sheath-forming materials through a multiplicity of openings in a conjugate sheath-core die to provide a highly entangled web of bicomponent fibers, each fiber comprising a continuous core of core-forming material substantially totally surrounded by a sheath of sheath-forming material;
• c) contacting said bicomponent fibers with a gas under pressure as they exit the sheath-core die sufficiently to attenuate said bicomponent fibers while they are still in their molten state to produce a web or roving of randomly dispersed entangled bicomponent fibers having an average diameter of about 10 microns or less;
• d) gathering said web of bicomponent fibers into a continuous rod-like shape;
• e) continuously heating said gathered web to render the same bondable at the points of contact of the fibers;
• f) cooling the resultant element to form a continuous rod defining a tortuous path for passage of smoke;
• and
• g) cutting the same into discrete lengths.

A method of making tobacco smoke filter means comprising:

• a) providing separate sources of a molten core-forming thermoplastic material and molten sheath-forming material comprising plasticized cellulose acetate;
• b) continuously extruding said molten core-forming and sheath-forming materials through a multiplicity of openings in a conjugate sheath-core die to provide a highly entangled web of bicomponent fibers, each fiber comprising a continuous core of core-forming material substantially totally surrounded by a sheath of sheath-forming material;
• c) gathering said web of bicomponent fibers into a rod-like shape;
• d) heating said gathered web to render the same bondable at the points of contact of the fibers;
• e) cooling the resultant element to form a continuous rod defining a tortuous path for passage of smoke;
• and
• f) cutting the same into discrete lengths.

A method of making tobacco smoke filter means comprising:

• a) providing separate sources of a molten core-forming thermoplastic material and a molten sheath-forming material comprising ethylene-vinyl acetate copolymer;
• b) continuously extruding said molten core-forming and sheath-forming materials through a multiplicity of openings in a conjugate sheath-core die to provide a highly entangled web of bicomponent fibers, each fiber comprising a continuous core of core-forming material substantially totally surrounded by a sheath of sheath-forming material;
• c) gathering said web of bicomponent fibers into a rod-like shape;
• d) heating said gathered web to render the same bondable at the points of contact of the fibers;
• e) cooling the resultant element to form a continuous rod defining a tortuous path for passage of smoke;
• and
• f) cutting the same into discrete lengths.

A method of making tobacco smoke filter means comprising:

• a) providing separate sources of a molten core-forming thermoplastic material and molten sheath-forming material comprising polyvinyl alcohol;
• b) continuously extruding said molten core-forming and sheath-forming materials through a multiplicity of openings in a conjugate sheath-core die to provide a highly entangled web of bicomponent fibers, each fiber comprising a continuous core of core-forming material substantially totally surrounded by a sheath of sheath-forming material;
• c) gathering said web of bicomponent fibers into a rod-like shape;
• d) heating said gathered web to render the same bondable at the points of contact of the fibers;
• e) cooling the resultant element to form a continuous rod defining a tortuous path for passage of smoke;
• and
• f) cutting the same into discrete lengths.