JPH0115615B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for producing a nonwoven fabric made of continuous filaments. More specifically, the present invention relates to a method and apparatus for producing a uniform nonwoven web with improved spreadability between continuous filaments and less uneven filament density.

In the so-called spunbond method, a continuous filament is drawn using an air sucker or the like and then dispersed and deposited on a collecting surface to directly produce a nonwoven web.
An important technical challenge is to sufficiently spread the continuous filaments and disperse them uniformly to obtain a web without uneven filament density.
Various proposals have been made in the past.

For example, Special Publication No. 49-430, Special Publication No. 49-49-
Publication No. 4026 and Japanese Patent Application Laid-open No. 1183/1983 disclose a method for uniformly opening and dispersing filament groups by colliding a high-speed airflow and a group of filaments with a fan-shaped flow expansion collision plate that spreads in a fan-like manner in the direction of dispersion of the group of filaments. It describes how to do this.

Also, JP-A-49-125666 and JP-A-57-
Publication No. 112451 describes a method for improving fiber opening by repeatedly colliding a group of filaments ejected with high-speed airflow from a traction device ejection port against collision plates arranged in two stages or in multiple stages.

Furthermore, JP-A-56-101938 and JP-A-57-
Publication No. 89635 describes a method for improving fiber opening by making the collision plate a specific material when the filament is opened by colliding the filament with a collision plate.

Many other patents related to filament opening and dispersion have been proposed, and additional tests by the present inventors have shown that most of these patents have some effect on improving filament opening and dispersion. It has also been confirmed that there are methods that can achieve considerable web uniformity. However, in recent years,
As the use of nonwoven fabrics expands, there is a growing demand for nonwoven fabric webs with even more uniformity, and there is a need to develop new techniques that can achieve greater fiber opening and dispersion than ever before.

In view of these circumstances, the present inventors conducted research on a method for obtaining uniform opening and uniform dispersion of continuous filament groups. As a result, conventional filament opening methods include charging a group of filaments using a forced charging method using corona discharge, a frictional charging method using collision or contact, etc., to generate electrostatic repulsion between the filaments, and thereby opening the filaments together. This method has been commonly used. However, in all of these methods, the current state is that the charged filament group is run and dispersed in a substantially sagging pattern in the filament advancing direction.

The present inventors focused on this point and came up with the idea that in order to further improve fiber opening and dispersion due to electrostatic repulsion between charged filaments, it is necessary to increase the degree of freedom in the width direction of the filaments. Based on this, we further investigated ways to increase the degree of freedom in the width direction of the filament after charging.
This has led to the present invention.

That is, the gist of the present invention is as follows.

(1) After colliding a group of continuous filaments running in a nearly sagging shape with the airflow onto the same plane plate,
A nonwoven fabric made of continuous filaments, characterized in that the group of continuous filaments is separated and run in two or more directions at arbitrary width intervals in the width direction and deposited on a moving collection surface to form a nonwoven web. Production method.

(2) In an apparatus for manufacturing a nonwoven web by pulling a group of continuous filaments with an air sucker and then depositing them on a moving web collection surface, a flat portion extending in the width direction is provided below the air sucker, and this 1. A nonwoven fabric manufacturing apparatus, characterized in that a yarn collision separator plate is incorporated therein, which has a surface continuous to the surface and separated in two or more directions at arbitrary width intervals in the width direction.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a perspective view for explaining the case where a group of continuous filaments spun in a substantially sagging shape from a narrow rectangular integral spinneret are drawn by a set of air suckers. FIG. 2 is an explanatory perspective view showing an embodiment of the present invention in which a continuous filament group spun from a plurality of split spinnerets arranged in the width direction is drawn by a plurality of air suckers. FIG. 3 is a perspective view for detailed explanation showing an example of the yarn collision separation plate 5 in the present invention.

In FIGS. 1 and 2, a continuous filament group 2 spun from a spinneret 1 is pulled and stretched by an air sucker 3 and then collides with a collision plate 4 to be charged and direction-changed, resulting in a substantially sagging shape. collides with the same plane plate portion 8 of the yarn collision separation plate 5 almost in a straight line, and continues on the plane 8 of the yarn collision separation plate 5 in two or more directions at arbitrary width intervals in the width direction. Separated yarn collision separation plate direction separation surface portion 9
The non-woven web 7 is deposited on the moving collection surface 6 while being separated and traveling along the surface.

Fig. 3 shows specific examples of the yarn collision separation plate used in the present invention, where A and B are examples where the yarn is separated and run in two directions, and C is an example where the yarn is separated and run in three directions. shows.

In the conventional opening and dispersion method, the filament group after being charged is run in a substantially sagging pattern, but in the present invention, the filament group after being charged is actively moved into two or more groups at arbitrary intervals in the width direction. By running the filaments separately in this direction, the filaments are sufficiently spread, and it is possible to form an unprecedentedly uniform nonwoven web with few filament density irregularities across the width.

Next, the present invention will be specifically explained with reference to Examples.

Incidentally, the 1 cm basis weight variation rate [%] in the examples was measured by the following method.

1 cm basis weight variation rate [%]: Cut the obtained web in the width direction at 1 cm width intervals and 100 cm length to collect 50 tanzak-shaped samples, measure the weight of each sample, Calculate the 1cm width basis weight variation rate using the following formula.

1cm width basis weight variation rate [%] = maximum weight - minimum weight / average weight x 100 Example 1 Using a device as shown in Figure 1, a discharge amount of 425 ml was produced from a rectangular integrated spinneret having 500 spinning holes.
After spinning polyethylene terephthalate at a speed of 5,000 m/min using an air sucker having a rectangular slit with a width of 600 m/m (in the machine width direction), it is collided with the first stage collision plate to charge electricity and change direction. continuous filament group and no,
The filaments were opened and dispersed using a yarn collision separation plate with a separation width interval of 10 m/m and a separation angle of 20°, and then deposited on a collection conveyor to produce a web of 50 g/m ² . This web had no multi-filaments or localized web accumulation spots due to poor opening, and its apparent quality was extremely excellent.
In addition, 50 tanzak-shaped samples were taken from a web measuring 50 cm wide x 100 cm long, excluding the ears, and cut into 1 cm wide and 100 cm long, and the rate of variation [%] in 1 cm width was measured.10 % or less, and the weight distribution of the web was also extremely uniform.

On the other hand, instead of the yarn collision separator plate, the width
A 50 g/m ² web was produced under the same spinning conditions except that a flat plate with a length of 600 m/m (machine width direction) and 50 mm was used. Compared to the web produced using the yarn collision separator, this web had conspicuous multi-filaments and localized web accumulation spots due to poor fiber opening, and the apparent quality was significantly inferior.
The width basis weight variation rate [%] was also 20%, and the weight distribution of the web was also large.

Example 2 Using an apparatus as shown in FIG. 2, six spinnerets each having 68 spinning holes were arranged in a horizontal row, and polyethylene terephthalate was spun at a total discharge rate of 682 g/min. This group of spun continuous filaments is pulled at a speed of 5000 m/min by using 6 air sutchers arranged in a row at equal intervals of 90 mm in the stacking width direction directly below the spinneret, with 68 filaments per air suction car. After that, the filaments are collided with the first-stage collision plate installed at the outlet of each air sucker to be charged and direction-changed, forming a continuous filament group with a substantially sagging shape, and yarns with a separation width interval of 5 m/m and a separation angle of 30 degrees. The filaments were opened and dispersed using a collision separation plate, and then stacked on a collection conveyor to produce a web of 50 g/m ² . This web has no multi-filaments or localized web accumulation spots due to poor opening, and its apparent quality is extremely high.
The 1 cm width basis weight variation rate [%] was 14% or less, and the weight distribution of the web was extremely uniform.

In the present invention, firstly, the filaments are arranged in a substantially sagging shape in the width direction, secondly, the filaments running in a substantially sagging shape are made to collide at one end on the same plane plate, and thirdly, the filaments are made to collide on the same plane plate. By using a method and device that separates and runs the group of filaments in two or more directions at arbitrary width intervals immediately after colliding, the filaments are sufficiently opened and there are few filament density irregularities. It has now become possible to form a uniform nonwoven web.

[Brief explanation of drawings]

1 and 2 are perspective views for explaining the manufacturing method and manufacturing apparatus of the present invention. FIG. 3 is an explanatory perspective view showing a specific example of the yarn collision separation plate used in the present invention. 1... Spinneret, 2... Continuous filament group, 3...
Air sucker, 4... Collision plate, 5... Yarn collision separation plate, 6... Moving collection surface, 7... Web, 8... Yarn collision separation plate coplanar plate portion, 9... Yarn collision separation plate direction separation surface portion.

Claims (1)

[Scope of Claims] 1. After colliding a group of continuous filaments running in a substantially sagging shape with an air flow on the same plane plate, the group of continuous filaments is separated in the width direction at arbitrary width intervals.
1. A method for producing a nonwoven fabric made of continuous filaments, characterized by forming a nonwoven web by depositing them on a moving collection surface while separating and running in two or more directions. 2. In an apparatus for manufacturing a nonwoven web by pulling a group of continuous filaments with an air sucker and then depositing them on a moving web collection surface, there is a flat portion below the air sucker across the width, and a continuous filament on this surface. 1. A nonwoven fabric manufacturing apparatus characterized in that a yarn collision separator plate having surfaces separated in two or more directions at arbitrary width intervals in the width direction is incorporated.