Melt spinning method and its apparatus

Details Melt spinning method and its apparatus Melt spinning method and its apparatus

1999-03-24

2001-08-21

Nguyen, Nam (Department: 1722)

Plastic and nonmetallic article shaping or treating: processes

Direct application of electrical or wave energy to work

Extrusion molding

C264S211140, C264S211150, C425S066000, C425S072200, C425S17480E

Reexamination Certificate

active

06277320

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a method and apparatus for melt-spinning thermoplastic polymer that prevents filaments from contacting one another in an unstable area generated necessarily during the rapid thinning of the filaments.
BACKGROUND OF THE INVENTION
The melt spinning method conventionally uses a melt spinning apparatus
1
comprising an ejecting device
2
, a spinning chimney
3
, an oiling device
4
, and a winding device
5
, as shown in
FIG. 3
, in order to cool and solidify each molten filament ejected from a plurality of nozzles provided at a spinning pack
2
a
of the ejecting device
2
, using a cooling device
6
provided in the spinning chimney
3
. The method subsequently assembles a plurality of filaments F at a converging portion B below the oiling device
4
to form a single yarn Y, which is then wound by the winding device
5
.
The melt spinning method involves an unstable area (the so-called “necking area”) generated necessarily during the rapid thinning of the filaments F. In the unstable area A, each filament F increases its speed while being rapidly thinned, but the thinning condition differs for each filament, partly because the cooling condition differs between the inside and outside of the filament F. Thus, at a given height in the unstable area, a given filament F does not necessarily move at the same speed as the other filaments F. Accordingly, when the filaments contact one another, fluffs or loops may occur which significantly reduce filament quality or, in the worst case, the filaments are severed and production efficiency is impaired.
Thus, in order to solve this problem, it is an object of the present invention to provide a melt spinning method and apparatus that prevents filaments passing through the unstable area from contacting one another.
SUMMARY OF THE INVENTION
The means employed by the present invention is a melt spinning method for thinning and solidifying each filament ejected from a plurality of nozzles to obtain a yarn comprising a plurality of filaments, characterized in that each filament being thinned is charged to the same polarity.
Since each filament being thinned is charged to the same polarity, the present invention allows filaments being thinned to repel one another and precludes them from contacting one another even if they tend to approach one another.
The means employed by the present invention is a melt spinning method characterized in that before the plurality of filaments are assembled together, charge is eliminated from them.
The present invention eliminates charges from the solidified filaments F prior to assembly, in order to smooth the assembly process.
The means employed by the present invention is a melt spinning apparatus having an unstable area formed due to the thinning of each filament between a spinning pack of an ejecting device located above and a filament converging portion located below, characterized in that a charging device is provided that charges each filament to the same polarity between the spinning pack and an inlet of the unstable area.
According to the present invention, the charging device charges each filament being thinned to the same polarity. Thus, the present invention allows filaments to repel one another and precludes them from contacting one another even if they tend to approach one another.
The means employed by the present invention is a melt spinning apparatus characterized in that a static eliminating device is provided that eliminates charges from each filament between an outlet of said unstable area and said filament converging portion.
According to the present invention, the static eliminating device eliminates charge from the solidified filaments F prior to assembly in order to smooth the assembly process.
The means employed by the present invention is a melt spinning apparatus characterized in that said charging device blows an ionized airflow toward a filament group passage formed between said spinning pack and the inlet of said unstable area.
The present invention can charge each filament to the same polarity by uniformly contacting the ionized airflow toward the plurality of filaments which pass through the filament group passage.
The means employed by the present invention is a melt spinning apparatus characterized in that said charging device includes electrodes for charging that surround the outside of the filament group passage formed between said spinning pack and said inlet of the unstable area.
According to the present invention, discharge from the electrodes ionizes the air in the filament group passage to enable each filament to be charged to the same polarity.


REFERENCES:
patent: 2338570 (1944-01-01), Childs
patent: 3097056 (1963-07-01), Rowlinson
patent: 4316716 (1982-02-01), Lin
patent: 4486365 (1984-12-01), Kliemann et al.
patent: 5122048 (1992-06-01), Deeds
patent: 51-23323 (1976-02-01), None
patent: 62-250211 (1987-10-01), None

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