Melt blown fiber structures for use in high strength wicks

Abstract

A high strength wick is presented that comprises a self-sustaining fibrous element. This element is formed of a multiplicity of fibers bonded to each other at spaced apart points of contact to define a porous matrix. The fibers are melt blown bicomponent fibers comprising a core of nylon 6,6 and a sheath of a polymer selected from the group consisting of polyethylene terephthalate and copolymers of polyethylene terephthalate. The sheath polymer is selected and adapted for solvent resistance.

Description

[0001] This is a complete application claiming benefit of provisional application Ser. No. 60 / 371,154 filed Apr. 10, 2002.BACKGROUND OF THE INVENTION [0002] 1. Technical Field [0003] The instant invention relates to unique polymeric bicomponent fibers and to the production of wicking devices, especially, nibs and ink reservoirs for writing and marking instruments made from such fibers. More specifically, this invention is directed to the production and use of nibs and ink reservoirs, particularly nibs for writing and marking instruments such as fiber tip pens and “felt tip” markers, as well as roller ball wicks for roller ball pens, wherein the wicking devices are formed of sheath-core, melt blown, bicomponent fibers wherein a core of a nylon 6,6 is substantially fully covered with a sheath of polyethylene terephthalate or a copolymer thereof. For the production of nibs, the core material may be polybutylene terephthalate. [0004] 2. Discussion of the Prior Art [0005] The production ...

AI Technical Summary

Benefits of technology

[0009] It is, therefore, a principal object of the instant invention to provide a method and apparatus for making writing and marking instrument components in a simple, efficient and inexpensive manner, yet having the property of unexpectedly improved drainback, exceptional solvent resistance in the presence of highly aggressive ink formulations, and increased stiffness and robustness, resisting degradation under pressure, particularly when used as a nib.

[0010] Another object of this invention is the provision of melt blown polymeric bicomponent fibers having a polyester sheath, particularly polyethylene terephthalate and copolymers thereof, totally surrounding a core of nylon 6,6, and the production of thermally bonded porous fibrous products for use as a nib, roller ball wick or ink reservoir in a writing or marking instrument which will not be significantly softened by the solvent in the ink and function effectively to retain and controllably feed ink from a reservoir to a writing surface even after extended use.

[0012] A further object of this invention is the provision of a high capacity ink reservoir for a writing or marking instrument defined by an elongated porous rod formed of a network of fine melt blown bicomponent fibers having a continuous sheath of polyethylene terephthalate or a copolymer thereof, and a core of nylon 6,6, and a nib for a roller ball or fiber-point pen or a felt-tipped marker, or the like, which are compatible with all currently-available ink formulations and provide an adequate release pressure to minimize “leakers” and “drainback”, and remain functionally effective over extended periods of use.

Problems solved by technology

Past attempts to produce nibs formed of bonded polyester fiber tows, particularly for use with writing and marking instruments incorporating such aggressive inks, have suffered unacceptable “drainback” properties.

While currently available polyester felt / phenolic nibs satisfy commercial drainback criteria, early polyester filament-based attempts to reproduce these properties failed.

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