JPH0663169B2 - Method for manufacturing non-woven fabric with excellent vertical strength - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a nonwoven fabric composed of continuous filaments. More specifically, the present invention relates to a method for producing a nonwoven fabric having excellent strength in the vertical direction by increasing the web pattern drawn by the filament groups in the vertical direction while improving the openability of continuous filaments.

Conventional technology The so-called spunbond method, in which continuous filaments are stretched by an air sacker or the like and then dispersed and deposited on the collection surface to directly produce a nonwoven web, is a spunbond method that utilizes the characteristics of continuous filaments for industrial materials and daily life materials. We are expanding the application mainly for agricultural and civil engineering materials, but depending on the application, there are different required characteristics such as those requiring strong, those requiring softness, and those requiring bulkiness. It is connected.

One of the applications of spunbond is tapes such as wire-holding tape, but these applications are particularly required to have tensile strength in the vertical direction.

It is known that the strength in the vertical direction is improved as much as the web pattern normally drawn by the filament is arranged in the vertical direction. For example, as disclosed in Japanese Patent Laid-Open No. 54-112273, Counder A method of arranging web patterns in the vertical direction by utilizing the effect has also been proposed.

Problems to be Solved by the Invention However, when actually arranging filament groups in the vertical direction, it is necessary to improve filament openability at the same time as arranging filament groups in the vertical direction, and if a non-woven fabric with a uniform basis weight is not formed, it is industrial. It turns out that it cannot be used for.

Therefore, the method of using the Counder effect or the method of arranging in the vertical direction by simply transferring the filament group is
It has a problem that it is not accompanied by the improvement of openability.

As a result of pursuing a method for manufacturing a non-woven fabric that simultaneously satisfies such an improvement in openability and an arrangement in the vertical direction, the inventors have separated the traveling of filament groups into two or more directions,
After that, a single web pattern was formed to complete a method for obtaining a non-woven fabric having a high basis weight uniformity and a strong vertical strength.

Means for Solving the Problems That is, in the present invention, when a filament group traveling downward in a scaly state together with an air stream is accumulated on a moving collecting surface to produce a nonwoven fabric, the moving collecting surface has an upper position. , The sudare filament group is divided in the width direction at an arbitrary width gap, and the divided filament groups are separated and run in two or more directions at separate angles, and then separated and run at separate angles. A method for producing a non-woven fabric, characterized in that the divided filament groups are mutually interfered with each other and integrated into one web pattern.

As a method of forming a filament group that travels in a substantially dull shape, for example, as shown in FIG. 1, a hole 2 of a rectangular spinneret 1 is used.
By pulling the discharged filament group 3 by an air flow with an air sucker 4 having a rectangular suction port, it is possible to form a filament group 5 that runs in a sloping manner. Normally, this filament group moves as it is. Collection surface 6
And the web 7 is formed.

In the present invention, the filament group that once runs in a dull manner is divided in the width direction at an arbitrary width interval, and the divided divided filament groups are separated and run in two or more directions. It is considered that by partially dividing the traveling, the flexibility of the filament in the width direction is increased, the filaments are easily opened one by one, and thus the uniformity is improved.

In this way, the split filament group that travels toward the moving collection surface in the state where the spreadability is improved has a small distance after separation when the separation angle θ is small, and the split filament groups are attracted to each other as a whole. To form one web pattern. Then, when the separation angle θ is gradually increased, one web pattern is drawn downward by the amount of the increase in the angle, and the patterns are gradually arranged in the vertical direction. The pattern will be drawn and the web will be formed at two locations on the moving collection map. This will be described with reference to FIG. 2. In FIG. 2 (A), the moving collection surface 6 is shown in FIG. FIG. 3 is a side view showing how the web 7 is formed. In this case, the filament group 5 travels substantially linearly with the air flow, and due to the diffusion of the air flow, it spreads to the end just before the moving collection surface 6. A web pattern is formed in a shape.

On the other hand, in FIG. 2 (B), the filament group 5 running in a sloping shape is separated in two directions at a small angle θ and viewed from the same side as FIG. 2 (A).
The filament group 5 that travels in a sloping manner is separated at a small angle θ, and the separated divided filament groups travel in two directions (see 10 and 11 in FIG. 3 (A)), but there is an air flow and an accompanying flow. Due to the relationship, the web patterns are attracted to each other to form a web pattern that extends in one vertical direction.

In FIG. 2 (C), it is separated in two directions at a large angle θ, and in this case, the divided filament groups are no longer attracted to each other, and the webs are formed in the respective traveling directions.

In the present invention, among such web formations, FIG.
As shown in (1), only the one that is adjusted so as to draw one pattern as a whole after being separated and run in two directions is a nonwoven fabric having excellent openability and improved vertical strength, which is the object of the present invention.

When separating into three or more directions, the same idea as in the case of two directions is required, and it is necessary to form one web pattern as a whole by interfering the divided filament groups separated into three directions once. Is.

If the web is formed at two places on the collecting surface, FIG. 2 (C)
In such a case, the angles θ ₁ and θ ₂ between the traveling directions of the divided filament groups and the collecting surface are smaller than 90 °, so that the air flow is reflected on the collecting surface and reflected. It is not preferable because the filaments are rearranged by the air flow and the openability is deteriorated.

Next, a method for dividing a filament group that runs in a slump form with an airflow into a divided filament group that divides and travels in two or more directions in the width direction at an arbitrary width interval will be described with reference to the drawings.

FIG. 3 (A) shows a flat plate 8 provided with a projection plate 9 having an angle θ and a length of 1 in the width direction. The group of filaments descends along the plane 8 and is separated into a group of divided filaments 10 traveling along the plane of the projecting plate 9 and a group of divided filaments 11 traveling along the plane of the flat plate 8. The angle θ is appropriately selected from 5 to 50 °, preferably 10 to 40 °,
The length 1 in the width direction is 2 to 50 mm, preferably 2 to 20 mm.

If the angle θ becomes too large, the separated divided filament groups will not draw one web pattern below. This is because the number of filaments of the divided filament group 11 traveling along the projecting plate 9 and the divided filament group 10 traveling along the flat plate 8 deviates too much, and the fiber-spreading effect is diminished. This is because if it is too large, streaky spots are likely to occur at the portion corresponding to the boundary between the projection plate and the flat plate.

FIG. 3 (B) shows a structure in which the colliding surface of the filament-like filament group 5 having a substantially dull shape is not a flat plate but already has a step. In this case, the angle θ and the length 1 in the width direction are shown in FIG. (A)
As described above, θ = 3 to 60 ° and l = 2 to 50 mm are selected.

In any case, the structure is not particularly limited to that shown in FIGS. 3 (A) and 3 (B) as long as it has a structure capable of separating traveling in two directions.

Further, FIG. 3 (C) shows an example of a separating device that separates in three directions, but separation in three or more directions can be easily performed.

Next, the present invention will be specifically described with reference to examples.

In addition, the 1 cm basis weight variation [%] in the examples is measured by the following method.

1 cm basis weight variation [%]: width of the obtained web in the width direction 1 cm
50 zigzag-shaped pieces cut at intervals and lengths of 100 cm
Take a sample of the book, weigh each sample,
Calculate the coefficient of variation in unit weight per 1 cm width using the following formula.

Example A group of 500 filaments made of polyethylene terephthalate was sucked by an air sucker having a rectangular inlet, and run in a row with a width of 500 mm. After that, a yarn separating device (separation angle θ = 30 °, as shown in FIG. 3 (A),
(Divided width l = 10 mm), with a separation angle of 10 mm in the width direction and a separation angle of 30 ° to make a divided filament group that runs separately in two directions, on a moving collection surface installed 600 mm below Was formed into a web so that the pressure would be 50 g / m ² . This web formation consists of one vertical flow pattern,
The nonwoven fabric obtained by thermocompression bonding between two heating rolls heated to 230 ° C. had the following properties.

3 cm width vertical strength 23.5 kg 1 cm width basis weight variation rate 6.8% Ten tapes obtained by slitting this non-woven fabric in the vertical direction to a width of 2 cm and a length of 1000 m were used as wire holding tapes and provided to a wrapping machine. However, the tape did not break at all.

On the other hand, the same filament group consisting of 500
The non-woven fabric obtained by forming a web on the moving and collecting surface so as not to separate in the direction of 50 g / m ² and thermocompression-bonding it with a heating roll at 230 ° C has a vertical strength of 3 cm and a width of 14.3 kg 1 cm width. The unit weight variation is 18.1%, and 10 tapes obtained by slitting 2 cm wide and 1000 m long in the vertical direction were also subjected to the wrapping machine.
There were a total of 5 cuts.

The effect of the present invention is to realize a method for manufacturing a non-woven fabric which simultaneously satisfies the improvement of openability and the arrangement in the vertical direction, and according to the manufacturing method of the present invention, as is clear from the examples,
It is possible to obtain a non-woven fabric having a high basis weight and a strong strength in the vertical direction.

[Brief description of drawings]

FIG. 1 is a perspective view for explaining a running state of a filament group traveling in a substantially sloping manner from a side surface, and FIG. 2 is a slump-like filament group traveling toward a moving collecting surface and two directions. FIG. 3 is a side view showing a state of a split filament group that runs separately, and FIG. 3 shows a specific example of a yarn separating plate for running the filament-like filament group in a separate angle in two or more directions at separate angles. FIG. 5 is an explanatory perspective view showing 1 ... Spindle, 2 ... Spinhole, 3 ... Discharged filament group, 4 ... Rectangular air heater, 5 ... Filament group that runs in a sloppy manner, 6 ... Moveable collecting surface, 7 ......
Web, 8 ... Flat plate of yarn separating device, 9 ... Projection plate, 10
...... Divided filament group that runs along a flat plate, 11 ……
A group of split filaments that run alongside the protruding plate.

Claims (1)

[Claims] 1. When manufacturing a nonwoven fabric by accumulating filament groups running downward in a slump form together with an air flow on a moving collection face, at the upper position of the moving collection face, the sloping filament group is widened. Direction, and the divided filament groups divided into two or more directions are separated and run in separate directions, and then the divided filament groups that are separated and run at separated angles are made to interfere with each other. A method for producing a non-woven fabric, which is characterized in that it is accumulated in one web pattern.