JPH06158503A - Method for opening filament bundle - Google Patents

Abstract

PURPOSE:To uniformly electrify and open various monofilament bundles of no twist to a monofilament level. CONSTITUTION:A filament bundle of no twist is electrified by rubbing with friction bars 2 and corona discharge is applied thereto. The electrified opened state of the filament bundle is regulated and the resultant filament bundle is introduced into an air gun 7, uniformly and stably electrified and opened to a monofilament level by electrified repulsion force and diffusion effects of air in the air gun. Thereby, the various filament bundles of no twist prepared by spinning, drawing the filaments and then winding the filaments once onto a bobbin, etc., can uniformly be electrified and stably opened even to a monofilament state. Even when the operation is performed in direct connection to spinning, the opening can stably be carried out by application of a relatively low corona discharge voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for opening filamentous bundles, and more specifically, it uses a combination of frictional charging and corona discharge application to adjust the charging state and electrostatic repulsion force and compressed air flow. The present invention relates to a method of opening a filament into a monofilament by the action of, and is particularly suitable for opening an untwisted filament bundle once wound. The opened filaments can be collected in a sheet form and then formed into a long-fiber nonwoven fabric by appropriate adhesion or entanglement.

[0002]

2. Description of the Related Art Various methods for electrostatically opening filament bundles have been proposed. Broadly speaking, a method of charging and opening the filament bundle by friction or collision between the filament bundle and another object, and corona discharge electric field There is a method in which the filament bundle is forcedly applied from the outside by passing it through the inside or by bringing the filament bundle into contact with an object or the like charged with the high voltage to charge and open the fiber. For example, in the former case
No. 4993, Japanese Patent Application No. 3-311676, etc. are proposed, and in the latter, Japanese Patent Publication No. 54-28508.
Japanese Patent Publication No. 63-42016, Japanese Patent Publication No. 63-2410
No. 6 publication is proposed.

[0003]

According to the studies made by the present inventors, the prior art has the following problems in order to uniformly, neatly, and stably perform a filament opening process on a filament bundle. Things turned out. That is, Japanese Patent Publication No. 37-4993,
In Japanese Patent Application No. 03-311676, the filament bundle is subjected to static electricity by friction with a friction element or by contact peeling with a metal roll to perform an opening process.
However, it is difficult to adjust the charged state of the filament bundle by such a method. For example, when the charge is insufficient, the contact state with the friction element is strengthened, that is, the tension applied to the filament is increased or the Nelson roll is used. You have to increase the number of rounds to the. In such a case, the former has a problem that the filament is broken by increasing the tension and the latter cannot cope with such a phenomenon during the opening process. On the contrary, even when the charging is excessively performed, there are few measures to be taken, and there arises a problem that the filaments are charged around each part of the device due to charging and the like.

On the other hand, in Japanese Examined Patent Publication No. 54-28508 and Japanese Examined Patent Publication No. 6342016, the filament bundle is formed by passing it through a corona discharge electric field consisting of a needle electrode and a flat plate target electrode with an air gun. Is being charged. According to these methods, it is possible to adjust the charged state of the filament bundle, but the filament bundle is shaken by the fluctuation of the air flow, and it is difficult to stabilize the distance to the needle electrode in particular, so that it is not possible to uniformly charge the whole. difficult. Further, according to the study by the present inventors, the filament-converging yarn that has been once wound up is overlapped with the filaments in the bundle due to its converging property. It was impossible to uniformly charge and open the entire bundle even if the filament bundle was passed through any position in the corona discharge electric field. As in Japanese Patent Publication No. 63-24106, it is difficult to uniformly charge and spread the bundle of focused filaments even in the contact charging by the collision with the charging plate.

The present invention solves the above-mentioned problems by opening a filamentous bundle, and in particular, even in the case of a non-twisted filament bundle that has been wound up, it is uniformly charged without applying excessive tension to the filament bundle, This method proposes a method of satisfactorily opening a fiber without winding around a roll.

[0006]

The inventors of the present invention have made extensive studies in order to solve the problems that could not be achieved by the prior art as described above, and as a result, have reached the invention as described below. That is, the present invention introduces a non-twisted filament bundle to a metal roll to be driven after being triboelectrically charged by a friction element,
A filament bundle opening method characterized in that after the charged state is adjusted by corona discharge using the metal roll as a target electrode on the metal roll, it is introduced into an air gun and jetted together with a compressed air flow, and simultaneously opened. is there.

The method of the present invention can be carried out by using the untwisted filament bundle obtained by melt spinning or the like as it is or by using the untwisted filament bundle yarn which has been once wound. It is suitable for opening untwisted filament bundled yarn once wound, which is difficult to perform. The present invention will be described in detail below with respect to the case of opening a once-wound untwisted filament bundled yarn.

In the present invention, the untwisted filament bundled yarn which has been once wound is a substantially untwisted continuous filament bundle, which means various fibers of organic, inorganic, synthetic and chemical, but generally polyester. , Polyamide, polyolefin, polyvinyl alcohol, polyurethane, polycarbonate, aramid, polyarylate, rayon fiber and the like, and copolyester, copolyamide, copolyolefin fiber and the like. The form of use is that once taken up on a bobbin or the like. A schematic diagram of the device used in the present invention is shown in FIG. 1, by which its construction is described. The substantially untwisted filament bundle is rolled out so that there is substantially no twist. Then, it is rubbed by the friction bar and charged. The material of the friction bar as the friction element used at this time depends on the type of the fiber bundle, but a metal rod having a surface chrome plating and having a mirror surface or a satin finish, a copper rod, or the like is used.

The filament bundle charged by friction with the friction element is then wound several times around the driving metal roll and the separate roll in a Nelson-like manner so that twists do not mix, and is taken up by this. The filament bundle in which the filaments have already been charged and opened to some extent and each filament has spread is applied with a corona discharge voltage on the driving metal roll in a state where the filament bundle is completely in contact with the metal roll. As the corona discharge electrode, a well-known one having several needle-like shapes, or another suitable shape is used as the electrode. The width of the electrode preferably covers the entire width of the filament bundle wound in a Nelson shape. At this time, the distance between the electrode and the metal roll as the target electrode is set to 5 to 40 mm, depending on the value of the applied voltage. Preferably 10
~ 20mm is good. The applied voltage value is processed at ± 10 to 80 KV and is adjusted depending on the configuration of the filament bundle and the state of triboelectric charging.

The electrification voltage of the filament bundle charged by friction with the friction element is determined by the material of the friction element and the type of the filament bundle.
It depends on various factors such as tension at the time of friction, single fiber fineness, number of filaments, moisture content, and the suitable electrification voltage for opening the filament bundle is the fiber material constituting the filament bundle, single fiber fineness, number of filaments, etc. Since it depends on the friction, it is generally difficult to set the optimum charged voltage for fiber opening only by friction by the friction element.

When the corona discharge polarity is excessively charged by frictional charging on the metal roll, a DC voltage opposite to the already-charged polarity is applied and the charge is actually eliminated, but the charged state and the spread state are adjusted. Is possible. In this manner, it is possible to prevent the trouble of winding the bundle of charged filaments around the metal roll or the like due to excessive charging. When the charged state of the filament bundle due to friction is insufficient, a corona discharge is applied to apply a DC voltage of the same polarity as the triboelectric charge polarity to adjust the charged and opened state of the filament bundle. As a result, even if a state of insufficient charging during friction occurs, the charged state of the filament bundle can be adjusted without increasing tension on the yarn due to the friction element, so that the influence of friction on the filament bundle can be minimized. In addition, since the filament bundle is frictionally charged prior to the application of the corona discharge voltage, the applied voltage can be lowered as compared with the case where the filament bundle is charged only by the corona discharge.

What is important in the above corona discharge treatment is
When the filaments were unwound, the filament bundles that had been bundled were charged and opened by friction treatment, and each filament in the filament bundle was separated to some extent. The tension between the metal roll and the separate roll keeps them in a neat state, and because of the yarn tension, the filament bundle passes through a stable fixed position on the metal roll without wobbling. Corona discharge charging processing is possible. This makes it very effective to use both triboelectric charging and corona discharge charging in order to realize a uniform charged state of the bundle of filaments, and it is also possible to adjust the charged state of the filament bundle. It is essential to apply the corona discharge on the metal roll before the charged filament bundle is guided to the air gun in order to adjust the charged state of the filament bundle and prevent the filament from winding around the metal roll, etc. especially when it is overcharged. is there.

The charged filament bundle that has passed through the metal roll is guided to the air gun and is ejected forward together with the high pressure air blown into the air gun. At the same time, the filament-bundle yarn can be uniformly opened into a monofilament by the opening action of each filament due to charging and the diffusion action of air. According to the method of the present invention, it is possible to obtain a very good opened state of the bundle of focused filaments by using a relatively simple apparatus and process.
The spread filaments thus obtained are deposited on a wire mesh belt conveyor-like collecting device that continuously moves by the air flow emitted from an air gun to form a web, and then calendering, needle punching and binder application. The fibers can be bonded or entangled by a method such as the above to obtain a long-fiber nonwoven fabric.

[0014]

EXAMPLES The present invention will now be described with reference to specific examples, but the present invention is not limited to these examples.

Example 1 and Comparative Example 1 Polyethylene terephthalate untwisted filament bundle 300d wound up on a bobbin using the apparatus shown in FIG.
r / 144f was used as a friction element and a satin finish bar having a surface chrome plating was used to feed the fiber at a speed of 1000 m /
A charge opening process was performed at a pressure of 2 kgf / cm ² for 2 minutes. The polyethylene terephthalate filament was charged to -2.0 KV by friction, and each filament was in a relatively disjointed state on the metal roll due to charging. When the corona discharge was not performed, the collected web was in a state of containing some unopened filament bundles. When the distance between the electrode and the roll was set to 15 mm on the metal roll in this state and a DC high voltage of −20 KV was applied by corona discharge, the filament bundle showed −3.
In the state of the collecting web charged with 5 KV, no unopened state part of the filament was observed, and the state was a very good opened state in which the web width was widened.

Comparative Example 2 The test of Example 1 was repeated except that the friction tension bar was removed. The filament bundle after the blow is -1.
The charged web was charged to 0 KV, but the opened state of the collection web was a state in which the bundle of unopened filaments was considerably contained, and the web opened state was not so clean.

Example 2, Comparative Example 3 Polyethylene terephthalate fiber untwisted filament bundle 3
When a fiber-opening blow test was conducted by rubbing 00dr / 288f at a fiber feeding speed of 1500 m / min, the filament bundle became overcharged when the feeding speed was accelerated and adhered to the metal roll, causing wrapping, and the fiber-opening test I could not do it. At this time, the electrification voltage of the filament bundle when wrapping occurred was -4.5 KV. Therefore,
When re-tested with + 30KV applied by using a corona discharger to eliminate static electricity, winding did not occur, and the collected web was in a very open and soft state with very few unopened filament bundles. Became.

Example 3 Polyvinyl alcohol untwisted filament bundle 1000 dr
/ 120f was applied triboelectrically after the triboelectric charging using the apparatus of FIG. 1 (potential of the same polarity as the triboelectric charging was applied when corona discharge was applied), and the collection web was in a very open state. .

Example 4, Comparative Example 4 Untwisted nylon / polyethylene terephthalate core-sheath composite spun fiber (nylon is the sheath component) 400 dr / 96
The f-filament bundle is subjected to triboelectrification using the device of FIG. 1 to remove the corona discharge (applying a potential having a polarity opposite to the charging polarity at the time of triboelectrification by corona discharge) to apply a charged voltage of + 1.5K
When a blown fiber opening test was conducted as V, a clean fiber opening web could be collected. If static electricity is not removed by corona discharge, the charged voltage of the filament bundle is + 3.0KV
As a result of excessive charging, winding around the rolls occurred frequently and a stable fiber-opening test could not be performed.

Example 5, Comparative Example 5 Untwisted polyarylate filament bundle 250 dr / 50
When f was charged and opened by friction, the charged voltage of the filament bundle was as low as -0.5 KV, and a satisfactory opened state could not be obtained. Therefore, when a blown test was carried out by applying a voltage of -30 KV by corona discharge, the blown filament bundle was opened very neatly, and the state of the collecting web was in a state containing almost no bundled unopened portion.

[0021]

As described above in detail in the examples, according to the method of the present invention, after spinning and drawing, various untwisted filament bundles once wound on a bobbin are uniformly charged. In addition, it is possible to stably open the fiber into a monofilament. Further, even when directly connected to spinning, the fiber can be stably opened by applying a relatively low corona discharge voltage. The filaments thus opened can be collected in the form of a sheet and subjected to a bonding treatment to form a uniform non-woven fabric with no open spots.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an example of a device used in the present invention.

[Explanation of symbols]

 1 Untwisted filament bundle bobbin 2 Friction bar 3 Driving metal roll 4 Separate roll 5 Electrode 6 DC high voltage power supply 7 Air gun 8 Open fiber

Claims (1)

[Claims] 1. A non-twisted filament bundle is triboelectrically charged by a friction element and then guided to a metal roll to be driven, and after the metal roll is subjected to corona discharge using the metal roll as a target electrode to adjust the charged state, A method of opening a filament bundle, which is characterized in that the filament is guided to an air gun and jetted together with a compressed air flow, and simultaneously opened.