JPS5851541B2 - Manufacturing method and device for long fiber nonwoven fabric - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for producing a long-fiber nonwoven fabric in which a continuous bundle of filaments is sucked by an ejector and laminated on a collection surface to form a web. The present invention relates to a method and apparatus for manufacturing.

In a method for manufacturing long-fiber nonwoven fabric in which a continuous bundle of filaments is sucked by an ejector and laminated on a collection surface to produce a web, in order to produce a wide nonwoven fabric, the entire thickness of the nonwoven fabric to be produced is sucked by the ejector or ejector. The suction jet is caused to move transversely in the direction perpendicular to the traveling direction of the web collection device, that is, in the width direction of the web. They need to be placed side by side.

However, the former method requires a complicated device to transversely move the ejector or the jet flow from the ejector, and also requires a wide uniformity when the manufacturing conditions, that is, the traveling speed of the collection surface reaches several meters or tens of meters per minute. In order to produce a uniform web, it is necessary to perform transverse motion at a considerable speed, which is difficult to produce in practice.

On the other hand, although the latter method does not require complicated equipment like the former and is capable of producing a wide and uniform web without being restricted by the advancing speed of the collection surface, it is difficult to manufacture. The strength of the nonwoven fabric in the web traveling direction, that is, the vertical direction, is greater than the strength in the direction perpendicular to the web traveling direction, that is, the horizontal direction, and the disadvantage is that only an anisotropic nonwoven fabric with a difference in strength in the vertical and horizontal directions can be obtained. There is.

As mentioned above, the present inventors have diligently investigated the reason why only an anisotropic nonwoven fabric having a vertical strength greater than a horizontal strength can be obtained by arranging a large number of ejectors in one row or in multiple rows in the horizontal direction. As a result, when the air ejected from each ejector reaches the web collection surface, it collides with the air walls of other ejectors that are horizontally adjacent to each other, instead of forming an isotropic circular pattern, and the web collection surface is blocked. The cause was found to be that the horizontal spreading of the surface is inhibited, which reduces the horizontal spreading and entanglement of the filaments that make up the web.

That is, when using known ejectors to deposit filaments onto a web collection surface to form a web, the filaments are dispersed within the boundary area of the free air jet of the ejector jet, but the distribution of the filaments within the jet is It is not uniform and more filaments are deposited closer to the center.

Therefore, in order to deposit a uniform amount of filaments over the entire length of the nonwoven fabric to be manufactured and to obtain a nonwoven fabric with no unevenness in the fabric weight (weight per unit area) in the width direction, the intervals between the ejectors arranged in the width direction should be adjusted. The boundary areas of the free air jets of each ejector should be kept close enough to overlap to a significant degree.

Therefore, the ejected flow from each ejector collides with the wall of the ejected flow of the adjacent ejector, preventing the web collection surface from spreading in the horizontal direction. form a pattern.

In the web obtained by such a pattern,
The spread and entanglement of the filaments in the short axis direction of the pattern, that is, in the horizontal direction of the web, is small, and therefore the longitudinal strength of the obtained nonwoven fabric becomes anisotropic, which is greater than the horizontal strength.

However, based on the above-mentioned fact, in order to manufacture an isotropic non-woven fabric with a vertical and horizontal strength ratio close to 1, the interval between each ejector was widened to such an extent that the boundary areas of their free air jets did not overlap that much. Even if it is produced, the result is that the horizontal strength of the obtained nonwoven fabric is not much greater than the vertical strength, and the effect is small even though it involves the troublesome condition change of changing the spacing of each ejector.

In other words, as a result of widening the spacing between each ejector, the interference force of the jet flow from each ejector with the jet flow of the adjacent ejector is weakened, and the filament pattern drawn on the web collection surface approaches a circular shape, but As mentioned above, there is a natural limit to manufacturing a nonwoven fabric that is uniform in the width direction without unevenness, and it is impossible to widen the spacing between each ejector to the extent that the jet flow from each ejector can be formed into a completely circular pattern. It's impossible.

Furthermore, even if two or more rows of ejectors are arranged in a so-called staggered arrangement in the direction of the collection surface width so as to mutually compensate for unevenness, the entanglement of the filaments between each row is small, and the distance between each row is set to allow for entanglement. The entanglement of filaments that can be obtained even if the filaments are brought close together is in the traveling direction of the web, that is, the longitudinal direction of the nonwoven fabric. No.

Furthermore, in the nonwoven fabric obtained by changing the spacing of each ejector as described above, it is impossible to produce a nonwoven fabric in which the horizontal strength is greater than the vertical strength, that is, the ratio of vertical strength to horizontal strength is less than 1. It is.

The present inventors focused on the above facts and conducted intensive research, and as a result, they arrived at the present invention.

That is, the present invention provides a continuous bundle of filaments that is sent out by a large number of ejectors arranged in one or more rows in a direction perpendicular to the traveling direction of a web collection surface, and is laminated on a collection surface to form a web. In a method for producing a fibrous nonwoven fabric, the lower part of each ejector injection pipe is inserted into a diffusion device having a non-circular cross-sectional shape whose long axis is elongated in one direction perpendicular to the traveling direction of a web collection surface, and the ejector is inserted into a recess on the inner surface of the diffusion device. A method for producing a long fiber nonwoven fabric having an arbitrary vertical and horizontal strength ratio, the method comprising adjusting the injection tube insertion length,
The apparatus for carrying out the method of the present invention has a plurality of ejector injection pipes arranged in one or more rows in the traveling direction of the web collecting surface, and the long axis is an opening in the direction perpendicular to the traveling direction of the web collecting surface. This is a manufacturing device for a long fiber nonwoven fabric in which the lower part of the injection tube is inserted into a diffusion device having a non-circular cross-sectional shape with an angle O and an end extending in one direction so that the insertion length can be adjusted.

Commonly used ejectors have circular fluid injection orifices, so that the filaments are deposited in a circular pattern as shown in FIG. 1 within the boundary area of the free air jet of the ejector jet.

When a large number of ejectors are arranged in a line in the direction of travel of the web collecting surface and the angle of view, the jets collide with the walls of the jets of adjacent ejectors as described above, causing the web to travel in the direction of travel (as shown in Figure 2). It is deposited in an elliptical pattern with its long axis at (indicated by the arrow inside).

Therefore, when a large number of ejectors are arranged in a line, in order to draw a circular pattern as shown in Fig. 1 or an elliptical pattern with the long axis perpendicular to the web traveling direction as shown in Fig. 3, , a diffusion device is attached with a non-circular injection port that is long in one direction so that the ejected flow from each ejector alone draws an oval pattern as shown in FIG. 3, and the long axis of the diffusion device is attached to the It must be placed in a direction perpendicular to the direction of movement of the collection device.

If a web is manufactured by this method, the shape of the diffusion device attached to the ejector, that is, if the opening angle is large, the pattern drawn by the jet stream from each ejector on the web collection surface will be long in the direction perpendicular to the web traveling direction. A nonwoven fabric is produced in which an oval pattern with an axis is formed, and the horizontal strength of the obtained nonwoven fabric is larger than the vertical strength.On the other hand, when the opening angle is small, the ejected flow from each ejector is drawn on the web collection surface (pattern The shape of the nonwoven fabric is close to a circle, and therefore, an isotropic nonwoven fabric whose horizontal strength is close to the vertical strength is produced.

In other words, the shape of the diffusion device depends on the length of the intended nonwoven fabric,
It is determined by the horizontal strength ratio, the pressure of high-pressure air supplied to the ejector that sends out the filament, and the inner diameter of the ejector injection port, and when the desired vertical and horizontal strength ratios or the air pressure supplied to the ejector vary. This causes the inconvenience of having to successively replace the diffusion device with one of the optimal shape.

An object of the present invention is to provide a simple method and apparatus for solving such inconveniences, and will be described in detail below with reference to the drawings.

FIG. 4 shows an embodiment of the diffusion device and ejector used in the present invention, in which the filament is sucked through the ejector inlet 2 by the action of high-pressure air supplied from the high-pressure air supply port 1 of the ejector, and is ejected by the ejector. It passes through the tube 3 and is deposited on the web collection surface below the jet 4.

The lower part of the ejector injection pipe 3 is inserted into the inner recess 6 of the diffusion device 5 so that its insertion length can be adjusted, and T is a screw for fixing the position of the diffusion device 5.

e is the opening angle of the diffuser 5, W is its inner width, D is the insertion amount of the ejector injection pipe 3 into the diffuser 5, L is the length of the diffuser 5, d is the inner diameter of the ejector injection pipe 3, and α is This is the apparent opening angle when the ejector injection pipe 3 is inserted into the diffusion device 5 by a length D.

FIG. 5 shows a specific example of the cross-sectional shape of the diffuser 5 in the airflow jetting direction.Practically speaking, it does not necessarily have to be an oval shape like a, but various shapes elongated in one direction like b, c, and d. is possible.

Under the condition that the ejector injection pipe 3 does not enter the inner surface recess 6 of the diffuser 5 at all, that is, f) = 0, the diffuser exhibits a spread determined by the opening angle e, and the most oblong pattern in this diffuser is formed on the web collection surface, and the horizontal strength of the resulting nonwoven fabric is sufficiently greater than the vertical strength.

That is, the vertical and horizontal strength ratios are sufficiently smaller than 1.

The optimum value of this opening angle e is fluid-dynamically determined by the flow rate and pressure of the air injected from the ejector injection pipe, and in practical terms, the pressure of the high-pressure air supplied to the ejector.

However, in practice, various factors such as the mixed fluid containing filaments and the internal resistance inside the diffusion device are added, and in the end, under normal usage conditions, that is, the pressure of the high-pressure air supplied to the ejector is 1. 5 kg/c
Opening angle O is 4° at 6kg/crtiG from rAG
A range of 32° is valid.

Furthermore, in this case, the inner width W of the diffuser is set to be approximately the same as the outer diameter of the ejector injection pipe in order to make the jet stream as elliptical as possible, and the length L of the diffuser is set so that the diffuser faithfully reproduces its opening angle O. The required amount to release, that is, the opening angle is O
The length must not exceed the minimum length that would result in the widest possible spread.

This is because if L is sufficiently long, even if the ejector injection pipe 3 is inserted into the inner recess 6 of the diffuser 5, it will spread as determined by the opening angle O, making it difficult to control the spread as the objective of the present invention. Moreover, as L becomes longer, the cross-sectional area of the diffuser outlet becomes larger, and the stalling of the airflow containing the filament increases, making it difficult to deposit the filament satisfactorily.

Therefore, the optimal length L of the diffuser varies depending on its opening angle e, but it is usually desirably 3 to 7 times the inner diameter d of the ejector injection pipe.

Under these conditions, when the ejector injection pipe 3 is inserted into the diffusion device 5 by D, the length of the diffusion device is long enough to fully exhibit the opening angle e. Therefore, although the appearance is the same as using a diffuser with an aperture angle α that is wider than the aperture angle O, the ejector jet flow actually follows the excessive aperture angle α of the diffuser. First, it becomes a so-called peeling jet, which separates from the inner wall of the diffuser, and conversely becomes a jet with a narrow spread.

Therefore, even though the same diffusion device is used, the spread is the same as if a separate diffusion device with a small opening angle was used, and as a result, the pattern drawn by the filament ejected from the ejector on the web collection surface is ,D
It becomes more circular than when = 0.

As a result, the horizontal strength of the obtained nonwoven fabric is close to the vertical strength, that is, the vertical strength ratio and the horizontal strength ratio are isotropic, close to 1.

If D is further increased and the injection pipe 3 of the ejector penetrates the inner recess of the diffuser 5 and becomes lower than the outlet of the diffuser, that is, if D>L, the diffuser will have no effect and the diffuser cannot be used. yields the same result as not having it,
Therefore, the vertical strength of the obtained nonwoven fabric is greater than the horizontal strength.

A nonwoven fabric having a weft strength ratio of greater than 1 is obtained.

In this way, nonwoven fabrics with arbitrary vertical and horizontal strength ratios can be easily applied by simply inserting the ejector injection tube into the diffusing device and changing the amount of insertion, without changing the opening angle of the diffusing device, that is, without the hassle of replacing the diffusing device. will be obtained.

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

Example 1 Twenty-four filaments were sucked into one ejector at an ejector supply air pressure of 4 kg/crlG, and deposited at a total denier of 144 on a web collection surface moving at a speed of 2 m/min.

The inner diameter d of the ejector injection tube was 10 mm, and the lower part of the injection tube was inserted into a diffusion device installed so that the long axis was in the width direction of the web collection surface.

Insertion amount of the ejector injection pipe into the diffusion device f) = O
w, length of diffuser L = 50mm, inner width W = 12m
ytt, and the results of measuring the pile pile of the web for various opening angles O are shown in the table below.

According to this, the useful opening angle range for a diffuser is 4°.
It was found that the angle was 32°.

Example 2 Ten ejectors were arranged in a row in the horizontal direction of the web collection surface, and 8 filaments were sucked into each ejector at a supply air pressure of 3 kg/crrtG, and each ejector was deposited on the web collection surface at a total denier of 24. .

Each ejector injection port was inserted into a diffusion device having an inner surface width W=12 mm, an opening angle of 0-16 degrees, and a length L-50 mm, which was provided so that the long axis was in the width direction of the web collection surface.

The table below shows the results of manufacturing nonwoven fabrics by variously changing the amount of insertion into the diffusion device when the inner diameter d of the ejector injection tube was 10 mm, and measuring the physical properties of the nonwoven fabrics.

According to this, when the ejector injection tube is not inserted into the inner recess of the diffuser, that is, at -D-00, the horizontal force is thicker than the vertical force, but when the ejector injection tube is inserted into the inner surface recess of the diffuser. The horizontal strength and the vertical strength become closer, and as D is further increased, the vertical strength becomes larger than the horizontal strength.

When D=80, the ejector injection tube completely penetrated the diffuser and became equivalent to the state without the diffuser, and the vertical force became significantly larger than the horizontal force.

Example 3 Twelve filaments were sucked into one ejector at an ejector supply air pressure of 4 kg/ctrlG, and deposited at a total denier of 144 on a web collection surface traveling at a speed of 2 m/min.

The ejector injection tube had a circular diameter d of 10 mgN, and the lower part of the injection tube was inserted into a diffusion device with an inner width W of 12tN and an opening angle of 016°, which was provided so that the long axis was in the width direction of the web collection surface.

The table below shows the results of depositing filaments on the web collection surface by varying the length L of the diffusion device and the amount of insertion of the ejector injection tube into the diffusion device, and measuring the deposition width.

According to this, when L is less than 30xm, there is no change in the deposition width even if the amount of insertion of the lid injection tube into the edger is changed, and therefore it is impossible to control the ratio of the vertical strength and the horizontal strength of the obtained web. .

Furthermore, when L exceeded 701 m, there was no change in the deposition width even if the ejector injection tube was slightly inserted into the diffusion device, and the stall of the ejected air flow was large, so that a satisfactory web could not be formed.

From the above, the inner diameter d of the ejector injection pipe is 10I.
It was found that when m and the opening angle O of the diffuser is 16°, the optimum length L is between 30 mm and 70 mm, that is, 3 to 7 times the inner diameter d of the ejector injection tube.

[Brief explanation of the drawing]

Figure 1 shows a single ejector with a circular fluid injection port, which is commonly used, and Figure 2 shows the effect on a web collection surface when ordinary ejectors are arranged in a row in a direction perpendicular to the traveling direction of the web collection surface. FIG. 3 shows a deposition pattern diagram in which a diffusion device having a long non-circular injection port in one direction is attached to the lower part of the ejector, and the long axis of the diffusion device is arranged in a direction perpendicular to the traveling direction of the web collection surface. FIG. 3 is a diagram showing a pattern of deposition on a web collection surface when the web is collected. Further, FIG. 4 is a cross-sectional view of the long fiber nonwoven fabric manufacturing apparatus according to the present invention, where A is a direction perpendicular to the traveling direction of the web collection surface.
B is a cross-sectional view in the traveling direction of the web collecting surface, and FIG.
-d is a specific example of the cross-sectional shape of the diffusion device used in the present invention in the direction of air jetting. 1... High pressure air supply port, 2... Ejector introduction port, 3... Ejector injection pipe, 4
...Injection port, 5...Diffusion device, 6...
...Inner recess, T...Position fixing screw.

Claims (1)

[Claims] 1. A continuous bundle of filaments is sent out by a large number of ejectors arranged in one or more rows in a direction perpendicular to the traveling direction of the web collection surface, and is laminated on the collection surface to form a web. In the method for producing a long fiber nonwoven fabric, the lower part of each ejector injection pipe is inserted into a diffusion device having a non-circular cross-sectional shape, the long axis of which is long in one direction perpendicular to the traveling direction of the web collection surface, and a concave portion on the inner surface of the diffusion device is inserted. A method for producing a long-fiber nonwoven fabric having an arbitrary vertical and horizontal strength ratio, the method comprising adjusting the length of an ejector injection tube inserted into the fabric. 2 1 or 2 rows in the direction perpendicular to the direction of travel of the web collection surface
A large number of ejector injection pipes are arranged in rows or more, and the lower part of the injection pipes is attached to a diffusion device having a non-circular cross-sectional shape whose end is elongated in one direction and whose long axis has an opening angle e in a direction perpendicular to the traveling direction of the web collection surface. A device for producing long fiber nonwoven fabric with adjustable insertion length. 3 Claim 2 in which the opening angle e is 4° to 32°
Manufacturing equipment as described in section. 4. The manufacturing apparatus according to claim 2 or 3, wherein the length L of the diffusion device is 3 to 7 times the inner diameter d of the ejector injection pipe.