JPH0834748B2 - Nonwoven web manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a wide web by a spunbond method, which improves the uniformity of the basis weight in the width direction and controls the fiber arrangement in the web.

<Prior art> Many methods are known as a method for making a nonwoven fabric from the spinning process all at once by the spunbond method. Among these various methods, various spinning conditions can be selected by making use of general-purpose spinning technology, and various spunbonds can be produced by generally collecting and dispersing filaments by air sucker from the spinneret. The method is, for example, a method in which the particles are taken off from the spinneret with a roll and then separated from the roll with an air sucker and dispersed.

As for the method for producing a web from such a bundle of continuous filaments, as shown in Japanese Patent Publication No. 374993/1974, the filaments are electrically charged and the non-woven fabric is produced by utilizing the electric repulsion between the filaments. A method of obtaining a web is known as a basic technique.

However, even with the method utilizing this electric repulsion, when the filaments ejected from the air sucker are deposited on the collecting surface of the net conveyor to form a web, the deposition distribution of the web is not uniform, and the ejection air flow and the ejection filaments are not However, it is easily affected by external factors such as an external air flow and lacks stability.

Also, in order to widen the width, there is a limit to the width of the web opened from one air sucker, so it is necessary to arrange multiple air suckers in the width direction of the net conveyor.
In this case, there is a defect that the deposition distribution changes due to the influence of adjacent weights, and it becomes difficult to make the basis weight in the width direction uniform.

In order to eliminate these drawbacks, for example, Japanese Patent Publication No.
No. 998 shows a method of controlling the stacking distribution of the filament group ejected from the air sucker by a suction device provided below the net conveyor, or a method of arranging so as not to be influenced by an adjacent weight. Further, Japanese Examined Patent Publication No. 47-24991 discloses a method for improving the deposition distribution by connecting members that change the ejection shape of the filament group under air sucker.

However, even with these methods, it is not possible to eliminate external factors and the influence of the adjacent weights, and it is difficult to make the unit weight distribution of the filament group supplied in a bundle from the air sucker stable and uniform. Is.

Furthermore, these methods have a serious problem that the arrangement of fibers in the deposited web, more specifically, the orientation of the fibers, is largely left to the control and is extremely difficult to control. ing.

The present inventors have focused their attention on such problems, and as a result of earnest research aimed at making the basis weight of non-woven webs uniform and controlling the vertical / horizontal arrangement of fibers that determine the directionality of the physical properties of nonwoven fabrics, It came to eggplant.

<Object of the Invention> An object of the invention is to provide a method for controlling the fiber arrangement while improving the uniformity of the basis weight in the width direction, particularly in the production of a wide nonwoven fabric by the spunbond method.

<Structure of the Invention> An object of the present invention is to provide a plurality of air suckers in the width direction of a net conveyor and channels provided at positions separated by spaces in each of the air suckers, and to supply from each air sucker. After discharging the bundle-like filament group from the long slit-shaped outlet and ejecting it as a fiber array pattern of a flat membrane filament group arbitrarily determined from the long slit-shaped outlet, the channel is mechanically moved in the direction perpendicular to the long side of the slit-shaped outlet. In the method of manufacturing a wide web having a uniform basis weight in the width direction by shaking the filament group while swinging the filament group, the channel is longer and wider than the inlet of the filament group. Has a skirt-like channel shape closed by a side plate having a large ratio of This is achieved by a method for producing a wide web by controlling a fiber arrangement, characterized in that the longitudinal direction can be changed at an acute angle with respect to the traveling direction of the net-shaped conveyor.

The channel used when carrying out the present invention has a slit-shaped outlet, and the longitudinal direction of this slit and the advancing direction of the deposition net conveyor are set to form an angle of 0 degree or more and less than 90 degrees. To be done. Normally, the channel selected and installed at an angle in the range of 0 to 70 degrees is swung in the direction perpendicular to the longitudinal direction, and the bundle of filaments spreads in the channel or in one direction after exiting the channel. Meanwhile, the fibers are deposited on the net conveyer while exhibiting a predetermined fiber arrangement as the channels swing in the direction perpendicular thereto.

When a filament group that is originally in the form of a bundle is spread in one direction by a channel, it is extremely difficult to make the distribution of the filament completely uniform in the spreading direction, but when the method of the present invention is used, the filament group This has the advantage that a uniform web can be produced without paying particular attention to the complete uniformity of the basis weight in the spreading direction in the channel.

That is, in the present invention, since the deposited web is mechanically shaken, it does not depend on the distribution in the spreading direction of the filament group ejected while spreading from the slit-shaped outlet of the channel, and in the width direction of the net conveyor. It can have a trapezoidal deposition distribution with a constant shape.

In this trapezoidal deposition distribution, the unit weight distribution of the flat part is extremely uniform, and the unit weight reduction parts at both ends are mechanically defined, so many air suckers are arranged in the width direction of the net conveyor to stack them. Even if it is performed, it is extremely easy to stack the weights.

In the present invention, the bundle-like filament group is expanded in the channel or after exiting the channel in the longitudinal direction of the channel. By changing the shape of the channel, the width of the filament group can be changed and / or the channel longitudinal direction. By changing the angle between the direction of movement of the web and the traveling direction of the net conveyor, the fiber arrangement of the nonwoven web can be controlled within a very wide range.

The channel referred to in the present invention is an inlet for a filament group in which at least two walls in the longitudinal direction are entirely formed with walls in order to accurately follow the oscillation of the filament group in accordance with mechanical oscillation. It means a member that spreads a bundle of filament groups in a flat curtain shape from the outlet to the outlet, and may have a skirt shape in which the aspect ratio of the outlet is larger than that of the inlet, and the filament group is spread in the channel. For this purpose, a collision plate or the like may be provided in front of the channel entrance or inside the channel.

The aspect ratio of the slit outlet of the channel is 1: 4 to 1: 4
00 is preferably 1: 8 to 1: 250 and can be changed depending on the desired widening of the filament group, that is, the fiber arrangement pattern in the web directly deposited on the net conveyor.

The channel material is not particularly limited, and may be a conductive material such as metal or ceramic, or a non-conductive material such as plastic.

The channel may or may not be connected to the air sucker, but usually it is preferable that the air sucker and the channel are separated.

The method of expanding the filament group in the channel separated from the air sucker does not cause the pressure loss of the air sucker which may occur in the method of directly connecting the device for widening under the air sucker.

Further, by swinging the bundle of filament groups while changing them into a flat curtain shape, it is possible to reduce the swing cycle determined according to the net conveyor speed.

Furthermore, by changing the bundle filament group to a flat curtain filament group, it is possible to widen the interval between the filaments, improve the single yarn openability of the web, and contribute to the quality improvement.

In the present invention, "uniform non-woven web" means a weight of 5 to
At 500 g / m ² , the variation of the unit weight in the width direction of 5 cm is the average unit weight.
It means within 10%.

The filament group supplied from the air sucker of the present invention includes, for example, those obtained by continuously taking out organic fibers such as polyester and polyamide polyolefin or inorganic fibers such as glass after spinning with air sucker, and preliminarily wound. It may be rewound and supplied.

The air sucker used in the present invention is generally an air sucker having a well-known structure, and the filament group is jetted from the outlet in a paired state in which the filament group is not twisted.

The advancing speed of the filament group used in the present invention is not limited and may be any speed, but normally 1000
A range of ~ 8000m / min is used.

In the present invention, the filament group is pre-charged in order to further improve the single-thread opening property of the web. The charging method may be any conventionally known method such as corona discharge or frictional charging. The method using discharge is more preferable. The corona discharge may be performed before or after air soccer, and optionally in any channel.

Further, corona discharge, triboelectric charging, collision plate electrification and the like may be appropriately used in combination.

The present invention will be described below with reference to the accompanying drawings showing an embodiment of an apparatus for carrying out the method for producing a nonwoven web of the present invention.

FIG. 1 is a front view schematically showing an example of a preferred embodiment of the device.

The filament group 1 discharged from the spinneret is drawn by a round air sucker 2 and drawn, or the filament group 1 sent at a constant speed by a roll group (not shown) is drawn by an air sucker, and then the needle electrode 3 and electrostatically charged in a corona discharge unit composed of a flat target 3 and a grounded target 4. A voltage is applied to the needle electrode 3 by being connected to a DC high voltage power source 5.

The charged filament group is suspended by a rotatable fulcrum 7, and is introduced into a channel 6 having a mechanism for performing a pendulum motion in an arbitrary set direction with respect to the net traveling direction.

The channel 6 swings in a direction orthogonal to the long side of the slit-shaped outlet of the channel while spreading the filament group and the associated airflow introduced into the channel into a flat curtain shape,
A uniform and controlled fiber arrangement web 8 is formed on the moving net conveyor.

FIG. 2 shows an example of the shape of a channel in which the filament group 1 is deformed into a flat curtain shape and which itself oscillates.
The shape of the channel may be trapezoidal as shown in (a) or may be a shape having a rectangular portion below the trapezoidal portion as shown in (c). Channels having a shape other than the shape shown may be used, but it is necessary that at least the two surfaces in the longitudinal direction are entirely formed with walls.

The side surface of the channel must be closed by the side surface 10 as shown in the side surface portion (b) on the left side of FIG. 2 (a).

FIG. 3 shows the cross-sectional shape of the web deposited on the net conveyor 9.

That is, (a) shows a longitudinal sectional view at a slit-shaped outlet of a nonwoven web in which the filament group ejected from the outlet of the channel 6 is directly deposited on the net conveyor 9 without rocking the channel, b) shows a lateral cross-sectional view of the net conveyor 9 of the non-woven web by arranging the channels 6 obliquely with respect to the net conveyor 9 and swinging them to deposit them on the net conveyor 9.

Even if the filament group is spread in a flat curtain shape in the channel 6, the uniformity of the distribution of the non-woven web is insufficient as shown in FIG. The web 8 having a uniform trapezoidal deposition distribution as shown in FIG. 6 (b) is provided by setting it at an arbitrary angle between 70 degrees and 70 degrees and shaking it in a direction orthogonal to the long side of the slit-shaped outlet of the channel 6. Obtainable.

The collision plate has a planar shape or a plate shape having a curvature and has a function of reflecting or sliding the filament group.

In the method of the present invention, by changing the swing angle of the channel performing the pendulum motion, or by changing the distance between the channel outlet and the net conveyor surface, a width of 1 m even for one weight, and in some cases, any web up to a width of about 2 m. Although it is possible to obtain it, it is important to increase the productivity industrially, and the method of multi-weight stacking in which a large number of one air sucker, a corona discharge unit and a channel are arranged in the width direction of the net conveyor is used. A wide web can be easily obtained.

FIG. 4 shows an example of a large number of laminated layers, (a)
Is a schematic plan view seen from directly above the net conveyor,
(B) is a schematic front view.

Filament groups ejected from a plurality of channels 6 arranged at mutual intervals a are guided by the plurality of channels 6 swinging in the direction of arrow E, accumulated on a net conveyor with a width b, and sequentially laminated and width. It is possible to easily obtain a uniform wide web having no streaks in the direction.

<Example> Hereinafter, the present invention will be described in detail with reference to Examples, and the performance of a nonwoven fabric made by using the nonwoven sheet obtained by the method of the present invention will be shown.

Example 1 Polyethylene terephthalate (in orthochlorphenol (ηSP / C-0.78) was melt-spun at 300 ° C. using a spinneret having a bore of 0.24 mm and 100 holes, and 90 c from the spinneret.
It was drawn and stretched with a round air sucker placed at the bottom of the m.

High pressure air with a pressure of 5 kg / cm ² G was supplied to the round air sucker.

The single yarn fineness of the filament group obtained under these conditions is 4
The forward speed of the filament group calculated from the single yarn fineness in denier was 5300 m / min. Further, this filament group was a circular bundle having a diameter of about 7 mm just below the exit of the air sucker.

This filament group is passed through a corona discharge unit, which is composed of electrode needles arranged 10 mm below the air sucker in 2.5 mm pitch and 10 needles arranged in a vertical line, and a flat plate target with a spacing of 17 mm. Charged. In this case, a high negative DC voltage of about 30 kV was applied to the electrode needle.

A skirt-like channel was placed 15 mm below the corona discharge unit, and a charged filament group was passed through it. In this example, the following two types of skirt-shaped channels were used.

(A) Height 300 mm, inlet shape 20 mm x 60 mm, outlet shape 2 mm
× 300mm aluminum skirt channel (b) Height 150mm, inlet shape 25mm × 80mm, outlet shape 4mm
X 170 mm Conducting skirt-shaped channel The respective setting directions of the suspension fulcrums of the two types of skirt-shaped channels with respect to the net advancing direction are 50 ° and 30 ° at an angle α shown in Fig. 7 (a). Two cases were selected in some cases.

These skirt-shaped channels are used for a rocking cycle of 200C.
By swaying in a direction orthogonal to the long side of the slit-shaped outlet at / min, the filament group moves at a speed of 15m / min on the net conveyor with the auxiliary action of the suction duct provided at the bottom of the net conveyor. Of a uniform non-woven web.

The nonwoven web was heat-pressed with a partial thermocompression-bonding roll (temperature: 200 ° C.), then impregnated with a polyvinyl alcohol resin, and cured at 140 ° C. for 2 minutes to give a nonwoven fabric.

Table 1 shows the uniformity of the basis weight of the non-woven fabric and the ratio of the vertical / horizontal direction of the non-woven fabric strength when the angle α in the channel fulcrum direction was changed for the two types of skirt-shaped channels.

It is proved from Table 1 that the non-woven fabric produced by the method of the present invention has a unit weight variation in the width direction of 10% or less, and that a non-woven fabric having uniformity can be obtained. By changing the shape and α (degree) of the skirt-shaped channel,
It was proved that the strong vertical / horizontal orientation of the non-woven fabric can be freely changed.

<Effects of the Invention> Since the method for manufacturing a nonwoven web according to the present invention is configured as described above, the method for manufacturing according to the present invention has the following effects.

 The openability of the single yarn constituting the nonwoven web is good.

The non-woven web has an excellent areal uniformity, with a variation in areal weight in the width direction of 10% or less.

The fiber arrangement of the nonwoven web can be easily changed, whereby the tensile strength ratio in the vertical / horizontal direction can be arbitrarily controlled.

It is possible to easily obtain a wide web having an effect of up to about 2 m.

[Brief description of drawings]

FIG. 1 is a schematic front view schematically showing an embodiment of an apparatus for carrying out the method for manufacturing a nonwoven web according to the present invention, and FIG.
It is a figure which shows the shape of the channel used for the apparatus shown in the figure, (a) is the front view and side view which show an example of a channel, (b) is the side view, (c) is a channel Fig. 3 is a front view showing another example of Fig. 3, Fig. 3 is a cross-sectional view showing the shape of a web deposited on a net conveyor, (a) is a web manufactured by a conventional method, and (b) is a A web made by the method of the present invention. FIG. 4 shows an embodiment in which a plurality of channels are arranged to cooperate with each other, (a) is a schematic plan view, and (b) is a schematic front view. 1 ... Filament group, 2 ... Air soccer, 3 ...
Corona discharge electrode needle, 4 ... Planar target, 5 ... DC high voltage power supply, 6 ... Channel, 7 ... Suspension fulcrum, 8 ...
Non-woven web, 9 ...... Net conveyor, 10 ...... Channel side plate, 11 ...... Channel front plate, a ...... Air sucker distance, 6 ...... Web width, E ...... Channel swing direction, G ...... Net Conveyor movement direction.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) References Japanese Patent Publication No. 42-27599 (JP, B1) Japanese Patent Publication No. 47-24991 (JP, B1) Japanese Patent Publication No. 56-17464 (JP, B2) Japanese Patent Publication No. 54- 28509 (JP, B2)

Claims (1)

[Claims] 1. A bundle of filaments supplied from each air sucker, wherein a plurality of air suckers and channels provided at positions separated by spaces are arranged in the width direction of a net conveyor. While jetting as a fiber array pattern of a flat membrane filament group arbitrarily determined from a long slit-shaped outlet after charging the group, by mechanically shaking the channel in a direction orthogonal to the long side of the slit-shaped outlet, In a method of manufacturing a wide web having a uniform basis weight in the width direction by swinging the filament group and depositing it on one web, the channel has a side plate having a larger vertical to horizontal ratio of the outlet than the inlet of the filament group. Has a skirt-like channel shape closed by a Method for producing a wide web to control the fiber array, characterized in that it is adapted to change at an acute angle to the traveling direction of the conveyor.