Method of producing fiber strand

Claim 1

A wet process of producing a continuous unitary coherent strand consisting essentially of twist-interlocked, staple inorganic fibers greater than colloidal in size, which comprises: a. preparing a noncolloidal water suspension of said staple inorganic fibers, said staple inorganic fibers comprising fibers greater than colloidal in size and having lengths of at least 1/4 inch; said noncolloidal water suspension having a viscosity in the range of 10,000 to 80,000 cps, a temperature in the range of 32° to 180°F, and a solids content in the range of approximately 3 to 7% by weight, and said noncolloidal water suspension being thickened with a reversibly gelable waterthickening agent to said viscosity range, thus maintaining said staple inorganic fibers noncolloidally dispersed in said water suspension and facilitating the orientation of said fibers generally parallel to each other; b. forming said noncolloidal water suspension into a strand by extrusion of said suspension containing said fibers oriented generally parallel to each other; c. converting said reversibly gelable waterthickening agent in the extruded strand into a substantially water-insoluble temporary gel binder which maintains the orientation of the fibers, permits the release of excess water from the strand, and is capable of being reverted to a water-soluble phase for subsequent removal; d. reducing the water content of the strand and, by twisting the strand, twisting together and mechanically interlocking the oriented staple fibers; and e. thereafter reverting the substantially water-insoluble temporary gel binder to a water-soluble phase and dissolving the same from the continuous unitary coherent strand of twist-interlocked fibers without destroying the mechanical interlock of the fibers or the continuous unitary nature of the strands.