Method of forming autogenously bonded non-woven fabric comprising bi-component fibers
AssigneeChisso Corporation
InventorsShozo Ejima, Susumu Tomioka, Tadao Matsumoto, Naruaki Hane
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Abstract
A porous non-woven fabric having a good dimensional stability and uniformity is prepared from a web obtained by arranging side-by-side composite fibers alone or a blend thereof with another fibrous material into a web and heat-treating the resulting web at a specified temperature, said composite fibers having few naturally developed crimps and being obtained by stretching unstretched side-by-side composite fibers consisting of a polypropylene component and an olefin polymer component having a specified melting point and a specified melt flow rate.
Claims7
A process for preparing a non-woven fabric having a porous structure which consists of
- (a) forming a plurality of unstretched side-by-side composite fibers consisting of a first component comprised mainly of crystalline polypropylene and a second component composed mainly of at least one olefin polymer other than crystalline polypropylene, said second component
- having a melting point at least 30.degree. C. lower than that of said polypropylene, and
- having a melt flow rate in the range of 1.5-5 times that of said polypropylene
- (b) stretching said unstretched composite fibers at a stretching temperature at or above 20.degree. C. below the melting point of said second component at a stretching ratio of 3 or more,
- (c) incorporating said stretched fibers having 12 crimps or less per 25 mm into a web,
- (d) subjecting said web to heat treatment at a temperature higher than the melting point of said second component but lower than the melting point of said polypropylene whereby said non-woven fabric is stabilized mainly by melt adhesion of said second component of said composite fibers.
A process for preparing a non-woven fabric having a porous structure which consists of
- (a) forming a plurality of unstretched side-by-side composite fibers consisting of a first component comprised mainly of crystalline polypropylene and a second component composed mainly of polyethylene, said polyethylene
- having a melting point at least 30.degree. C. lower than that of said polypropylene, and
- having a melt flow rate in the range of 1.5-5 times that of said polypropylene,
- (b) stretching said unstretched composite fibers at a stretching temperature at or above 20.degree. C. below the melting point of said polyethylene and at a stretching ratio of 3 or more,
- (c) forming said stretched fibers having 12 crimps or less per 25 mm into a web,
- (d) subjecting said web to heat treatment at a temperature higher than the melting point of said polyethylene but lower than the melting point of said polypropylene whereby said non-woven fabric is stabilized mainly by melt adhesion of the polyethylene of said composite fibers.
Dependencies are inferred from the claim text.