Acrylic fibers having improved dispersability in viscous organic or inorganic matrices

Claim 1

Agglomerates of fibers having improved dispersability in viscous inorganic matrices, constituted by staple acrylic fibers based on homopolymers or copolymers of acrylonitrile containing at least 50% by weight of acrylonitrile, and having a tenacity higher than 50 cN/tex, an initial modulus higher than 1000 cN/tex, and an elongation at break not higher than 15%, each fiber having a diameter less than 50 microns and a length greater than 3 mm and less than 60 mm, bonded to each other by a cohesion conferring-agent soluble or swellable in water or in an alkaline aqueous solution, said cohesion conferring-agent being employed in an amount within the range of from 1.5 to 7% by weight relative to the fibers, said fibers being obtained by: extrusion of the polymer through a die; coagulation of the filaments exiting the die; washing and wet-drafting, drying, collapsing at 150°-200° C.; further drafting of the filaments in the plastic state, up to a total draft ratio of at least 8; cooling down of the filaments under hindered retraction conditions; the number of acrylic fibers for each agglomerate being equal to or greater than ##EQU2## wherein L is the length of the fibers and D is the diameter of the fibers, both in millimeters.