Plastic article containing electrically conductive fibers

A thread comprising a bundle of conductive fibers, each fiber having a diameter of at most 0.015 mm, the fiber bundle being embedded in a polymer with a relatively low molecular weight which will enable even distribution of the conductive fibers, under minimal shear force and without substantial fiber breakage, within molded plastic articles formed from granules cut from the thread, said embedded bundle being dried to solidify the polymer and thereafter provided with a sheath of plastic material.

A thread comprising a bundle of conductive fibers, each fiber having a diameter of at most 0.015 mm, the fiber bundle being embedded in a polymer having a relatively low molecular weight which will enable even distribution of the conductive fibers, under minimal shear force and without substantial fiber breakage, within molded plastic articles formed from granules cut from the thread, said embedded bundle being provided with a sheath of plastic material different from the polymer in which the fiber bundle is embedded.

A fiber and plastic composite granule obtained by cutting pieces from an elongated thread comprised of a bundle of between 1,000 and 35,000 adjacent conductive, metal coated fibers embedded in a polymeric plastic material having a relatively low molecular weight which will enable even distribution of the conductive fibers, under minimal shear force and without substantial fiber breakage, within molded plastic articles formed from said granule, the diameter of said conductive fibers being at most about 0.015 mm and exhibiting a fiber conductivity of at least 0.5% of the copper standard.

A fiber and plastic composite granule obtained by cutting pieces from an elongated thread comprised of a bundle of conductive, metal coated fibers, each fiber having a diameter of at most 0.015 mm, the fiber bundle being embedded in a polymer with a relatively low molecular weight which will enable even distribution of the conductive fibers under minimal shear force and without substantial fiber breakage, within molded plastic articles formed from said granule, said embedded bundle being provided with a sheath of plastic material.

A granule with a length of 3 to 15 mm chopped from a composite thread for use in the moldings of an article capable of shielding against electromagnetic waves, said composite thread comprising from 1000 to 35000 electrically conductive fibers with a conductivity of at least 0.5% of the Cu-standard and a diameter of not more than 75 mm, embedded as a bundle in a relative low molecular weight polymer, said embedded bundle being sheathed with a layer comprising a different polymer said low molecular weight polymer enabling a gradual disintegration of the granule with minimal shear force on the conductive fibers so as to avoid substantial fiber breakage while the granule is kneaded during molding of the article, thus permitting an even electromagnetic shielding dispersion of the fibers throughout the article.

A molding material comprising natural synthetic resin pellets blended with granules obtained by cutting pieces from a thread comprised of a bundle containing between 1,000-35,000 adjacent conductive fibers, each said fiber having a diameter of at most 0.015 mm, the fiber bundle being embedded in a polymer having a relatively low molecular weight which will enable even distribution of the conductive fibers, under minimal shear force and without substantial fiber breakage, within molded plastic articles formed from granules cut from the thread, said embedded bundle being provided with an outer sheath of a plastic material.

A molding material comprising synthetic resin pellets blended with granules comprising a bundle of a number of strands of fibrous conductive filler provided inside a synthetic resin layer in a longitudinal direction thereof, wherein the conductive filler is a non-metallic fiber coated with a metal layer.

A thread comprising a bundle of conducive, metal coated fibers, each having a diameter of at most 0.015 mm, the fiber bundle being embedded in a polymer with a relative low molecular weight which will enable even distribution of the conductive fibers, under minimal shear force and without substantial fiber breakage, within molded plastic articles formed from granules cut from the thread, said embedded bundle being provided with a sheath of plastic material.

A method of continuously forming granules, which comprises the steps of continuously coating a bundle of fibrous conductive fillers with a polymer having a relatively low molecular weight which will enable even distribution of the conductive fibers, under minimal shear force and without substantial fiber breakage, within molded plastic articles formed from granules cut from the thread, drying the polymer, passing the coated bundle through an extruder for sheathing a synthetic resin layer around the coated bundle, and cutting the bundle sheathed with resin for providing granules, said coating being capable of stimulating the gradual disintegration of the bundle while mixing and working at high temperatures.

A process for forming plastic articles having at least predetermined conductive portions including the steps of:

• (a) providing a fiber/plastic composite having a conductive fibers content ranging from about 30 to about 70% vol. and having a substantially parallel fiber arrangement therein, wherein the conductive fibers are anchored in a polymeric plastic compatible with and of lower melting point, softening point and molecular weight than substantially pure polymeric plastic material to be admixed therewith
• (b) admixing this fiber/plastic composite from step (a) with a predetermined volume of substantially pure polymeric plastic material, and
• (c) heating said mixture and working the heated mixture while maintaining low shear conditions to avoid breakage of the fibers, but with sufficient shear to evenly distribute the fibers within the plastic.