JPH05125648A - Production of nonwoven web - Google Patents

Abstract

PURPOSE:To industrially and stably and readily obtain nonwoven fabric having a low basis weight coefficient of variation in the width direction by jetting a continuous multifilament fiber bundle of no twist together with compressed air from air guns arranged in one row into a hood of a specific construction. CONSTITUTION:Air guns 2 composed of many spindles for jetting an opened fiber bundle together with compressed air streams and side guns 3 for jetting only compressed air streams at both ends thereof are initially arranged in one row. A hood 4 having four sides surrounded by flat plates and regulated to narrow the slit width from the inlet part toward the outlet part is simultaneously arranged on the downstream side thereof. Opened continuous multifilament fiber bundles 1 of no twist, together with the compressed air, are then jetted from the air guns 2 into the hood 4. The opened fiber filaments passing through the hood 4 are subsequently collected on a moving collection conveyor 5 so as to mutually interlace. Thereby, the objective product is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to fabricate a non-twisted continuous multifilament fiber bundle together with a compressed air flow from an air gun arranged in a row and collect the bundle on a collecting conveyor to obtain a basis weight in the web width direction. The present invention relates to a method for producing a nonwoven web having a low fluctuation rate. The filament web collected in the form of a sheet can then be made into a long-fiber nonwoven fabric by appropriate adhesion or entanglement.

[0002]

2. Description of the Related Art There have been many proposals for uniforming the basis weight of a filament web collected in the form of a long-fiber nonwoven fabric sheet. Particularly, when a multi-weight air gun is used, it may be difficult to make the areal weight uniform, particularly the evenness in the sheet width direction. For example, if a bundle of fibers is jetted together with a compressed air flow from an air gun with only one air gun arranged in a line, if other air guns are placed on both sides, a collision with the jet air flow from the adjacent air gun will occur. Is prevented from spreading isotropically and air flows from the individual air guns escape in a direction perpendicular to the row of air guns. For this reason, the fiber filaments existing in the air flow also become the same as the air flow, and a low fiber existing rate, that is, a portion with a small basis weight is formed between the air guns. When the thus-blown material is collected on a moving conveyor net or the like provided downstream thereof, a sheet-like web having a non-uniform basis weight in which a large area and a small area are alternately repeated. As a method of uniformizing the basis weight, two or more sheet-like webs having such characteristics are stacked, that is, the phase of the large and small portions of the basis weight which are alternately repeated in one sheet is shifted. It is conceivable to aim at making the unit weight uniform by stacking and supplementing sheets in which large and small unit weights are alternately repeated. However, even if you actually try such a thing, the collision state of the air flow between the air guns is unstable and there is some shaking, so the falling position of the fiber filament in the direction between the air guns is not stable, the net The filaments piled up on each air gun unit are piled up with a very steep slope, so the piled web easily collapses due to the air flow from other air guns or surrounding air when stacking. Therefore, it is very difficult to obtain a sheet-shaped web having a uniform basis weight by this method.

The following has been proposed as a method for solving such a problem. That is, a method of setting a collision or a reflection plate under the air gun to regulate the position where it falls onto the collection net and at the same time flatten the state of the deposited web as much as possible. There is a method of doing so, a method of arranging two plates at the bottom of the air gun and blowing a fiber filament between them, and the first method is, for example, Japanese Patent Publication No. 63-24108 and Japanese Patent Publication No. 58-180655. In the third method, Japanese Patent Publication No. 2-462 and Japanese Patent Publication No. 3-3383.
No. 0, JP-A-59-88961, JP-A-1-
No. 321963 is available.

[0004]

According to the study by the present inventor, it was found that the above-mentioned conventional technique has the following problems. That is, in the method of Japanese Patent Publication No. 63-24108, which is the first method, the compressed air flow and the fiber filaments jetted from the multiple-pile air guns arranged in a row collide with each other on the same collision plate surface. The airflows of the fibers collide with each other and the uniform dispersion of the fiber filaments is hindered. Also,
In the method disclosed in Japanese Patent Laid-Open No. 58-180655, the obstacle due to the collision of the air flows from the air guns is solved because a separate collision plate is provided for each air gun, but the web of each fiber after collision is solved. Adjusting the width of the air gun for individual air guns is very time consuming. In addition, due to the vibration of the fibers at the time of collision, the webs that are caught by all means tend to have stripes due to the arrangement of the collision plates. In the second method, the size of the device becomes large, and it is difficult to adjust the number of swings when the speed of the collection belt is changed for the purpose of adjusting the weight of the web, etc. There is a limit to increasing the number of matching swings. Also,
Mottling unevenness is likely to occur when swinging and reversing. In the third method, Japanese Patent Publication No. 2-462, Japanese Patent Publication No. 3-33830, and Japanese Patent Laid-Open Publication No. 1-321963, plates curved in an arc shape are opposed to each other, and a space is once narrowed at an intermediate portion thereof. It has been proposed to blow fiber filaments with a stream of compressed air. If such a method is used, high-speed air from the air gun will try to flow along the front or back of the arcuate plate surface due to the Counder effect at the once narrowed position in the middle part, and the fiber flow will be very unstable. .. Due to this unstable shaking, the uniformity of the areal weight is improved to some extent, but there are many irregularities and it is impossible to make the uniform areal weight consistent. In addition, if the air flow is completely along either side by this method, it is easy for streaks to form directly under the air gun. JP-A-59-88961
In the method of the publication, a method of blowing a fiber filament between flat plate surfaces formed integrally with an electrode for corona discharge to the fiber downstream of the air gun is proposed. With the structure, since the secondary air sucked from around the air gun, which is important for uniforming the areal weight, is limited, it is difficult to make the areal weight uniform. Further, since the upper portion of the flat plate surface is integrated with the corona discharge electrode, even if an attempt is made to widen it in order to facilitate the suction of the secondary air, the range in which it can be widened is considerably limited due to its role as an electrode. The present inventors have arrived at the present invention as a result of earnestly studying a method for making the basis weight of a web sheet blown from a multi-weight air gun, which solves the above-mentioned problems of the prior art, uniform.

[0005]

That is, the present invention provides an air gun consisting of multiple spindles for ejecting an opened fiber bundle together with a compressed air stream in producing a nonwoven web from a non-twisted continuous multifilament fiber bundle. Side hoods that inject only compressed air flow are arranged in a line at both ends, and a hood that is surrounded by flat plates on all four sides and is adjusted so that the slit width becomes narrower from the inlet to the outlet. Arranging, injecting a non-twisted fiber bundle together with a compressed air flow from the air gun into the hood, and passing it through, and collecting on a moving collecting conveyor so that the open fiber filaments from adjacent air guns are entangled with each other. And a method for producing a nonwoven web. The non-twisted continuous multifilament fiber bundle as referred to in the present invention is essentially a multifilament fiber bundle in which no twist is added, that is, no twist is added by, for example, a twisting operation, and the material thereof is any These are various fibers of organic, inorganic, synthetic, and chemical, but generally polyester, polyamide, polyolefin, polyvinyl alcohol, polyurethane, polycarbonate, aramid, polyarylate, rayon and the like. The form of use is that once wound on a bobbin, etc., but even if it is continuous to the process in which those filaments are spun,
There is no problem.

Next, the present invention will be described in detail. FIG. 1 shows an outline of the apparatus, and FIG. 2 shows a side view. The untwisted continuous filament bundle 1 that has been opened is guided by an action of high-pressure compressed air into an air gun 2 that is conveyed, and the slit width is gradually narrowed from the entrance surrounded by a flat plate toward the exit. Blow into the hood made in.
At this time, a plurality of air guns are arranged in a line, and side guns 3 for blowing out only the air flow are installed at both ends thereof. The hood has a slit width of 10 mm or more at the entrance 1
Within a range of 00 mm or less, a range of 30 to 80 mm is preferable, and it is set wider than the slit width dimension of the outlet portion.
The desired slit width dimension of the outlet portion is set within the range of 5 mm or more and 10 mm or less. The combination of the slit widths of the inlet and the outlet varies to some extent depending on the flow rate of the air blown from the air gun and the side gun, but the size is set so that the opened fiber passes through the hood without being blocked. If the entrance and exit slit widths are set outside the above range,
The hood slit width needs to be set within the above range because a streak may be formed at an intermediate position between adjacent air guns of the collecting web and the web may be clogged in the hood. The air velocity distribution inside the hood is reduced by the effect that the hood is narrowed toward the tip by blowing only the open fiber and compressed air from multiple air guns into the hood assembled in this way and the compressed air from the side gun. Is evened out. By this action, the fibers blown by each air gun as a unit for opening fiber bundles facilitate the opening, and at the same time, a large swaying effect occurs in the width direction of the air gun in the hood. The sheets are entangled with each other and the sheet areal weight in the sheet width direction is made uniform. In order to realize this effect, it is essential that the hood be narrowed linearly from the inlet to the outlet. When a hood whose slit width does not change from the inlet to the outlet is used, the fiber filaments from the adjacent air guns do not entangle with each other, and each filament group becomes a strip with the unit weight in the width direction being a normal distribution. It will be collected as a result and the variation of the weight of the web in the width direction will be large. In addition, the compressed air blown from the side gun plays the role of an air curtain at both ends of the air gun row, regulates and stabilizes the dropping position of the opening filament, and suppresses its spread by the side plates to make the wind velocity distribution in the hood uniform and open. Promotes the oscillating movement of fiber. These effects can be achieved only by arranging the side guns at both ends of the air gun row in the hood, and the use of the side guns is very important. The filament web that has exited the hood is collected on the collecting net 6 that moves on the air suction device 7, and although not shown in the figure, a single layer of the filament web is then formed by an appropriate method, or multilayer superposition bonding is performed. By doing so, it is possible to obtain a long-fiber nonwoven fabric having a uniform basis weight.

According to the present invention, the opened untwisted continuous multifilament fiber bundle is jetted together with the compressed air stream from the multiple spindle air gun, and the side guns for jetting only the compressed air stream are arranged at both ends of the bundled side gun. A hood having four sides surrounded by a flat plate and having a slit width narrowed from the inlet part to the outlet part is installed, and the untwisted fiber bundles with the compressed air flow are jetted and passed through the hood from the air gun. The fiber bundles from the adjacent air guns can be collected on the moving collection conveyor so that the fiber bundles are entangled with each other and the basis weight in the sheet width direction is uniform. The filament web collected in the form of a sheet can be formed into a long-fiber nonwoven fabric by appropriate adhesion or entanglement.

[0008]

EXAMPLES Next, the present invention will be described with reference to examples, but the present invention is not limited to these examples. The fabric weight distribution in the width direction of the non-woven fabric sheet in the examples is obtained by removing the non-uniform fabric weights at both ends of the sheet, and then measuring the weight of a sample cut into a strip shape having a width of 10 mm and a length of 170 mm over the entire sheet width. It was The variation rate is the variation coefficient (standard deviation divided by the average value) multiplied by 100 and expressed in%.

Example 1 Using an apparatus as shown in FIG. 1, the entrance slit width is 30 mm,
100 liters of polyester fiber 300 dr / 96 fil. Which was charged and opened in the hood adjusted to the exit slit width of 7.5 mm
Blows 5 plumes at 0 m / min. At this time, 0.34 Nm ³ / min of air including the side gun was blown. The blown fiber was well opened at the place where it left the hood, and was in a state of being greatly shaken in the width direction of the hood. The collected web is
The fibers were very evenly dispersed. After heat bonding this web, the distribution of the areal weight of the sheet was measured. As a result, the average areal weight variation of 16 g / m ^{2 in the} width direction was 8.9%, and the areal weight variation in the longitudinal direction was 6.5%.

Example 2 When the hood size was changed to 90 mm at the inlet and 10 mm at the outlet under the same conditions as in Example 1, the dispersion state of the fibers in the collection web was good. The average areal weight is 26 g / m ² , and the variation in the areal weight of the sheet is 18.7% in the width direction and 7.4 in the longitudinal direction.
%Met.

Comparative Example 1 A blown test was conducted under the same conditions as in Example 1 except that the entrance slit width and the exit slit width of the hood were set to 10 mm and parallel slits were used. In the collected web, a small streak of web weight was clearly observed just below the intermediate position of the adjacent air gun. When the weight distribution of this web sheet was measured, the average weight was 30 g / m ² , and the weight variation was 33.1% in the width direction and 5.4% in the longitudinal direction.

Comparative Example 2 The entrance slit width and the exit slit width of the hood were 30 mm-4.
A blown test was conducted under the same conditions as in Example 1 with the combination of mm. The spread fibers blown into the hood gradually adhered to the inner wall of the hood and became clogged.

Comparative Example 3 The entrance slit width and the exit slit width of the hood are 120 mm-
A blown test was conducted under the same conditions as in Example 1 with a combination of 10 mm. The way the fiber filaments fly after exiting the hood was extremely uneven and unstable in the width direction of the hood. In the collected web, small streaks with web weight were clearly observed just below the intermediate position of the adjacent air gun. When the weight distribution of this web sheet was measured, the average weight was 33 g / m ² , the weight variation was 26.3% in the width direction,
It was 7.3% in the longitudinal direction.

Comparative Example 4 A blown test was carried out under the same conditions as in Example 1 except that the side gun was removed from the gun row and only the air gun was used. The fiber filaments after leaving the hood spread widely in the hood width direction, and the width of the collecting web widened, but the state of the end portion was very unstable. In addition, the fiber oscillating effect in the hood disappeared, the dispersion of the fiber filaments after leaving the hood was non-uniform, and the filament group for each air gun remained as it was. Therefore, the collection web was not observed to have a uniform basis weight in the width direction, and small streaks with a basis weight were clearly observed.

Example 3 Using the apparatus of FIG. 1, polyvinyl alcohol fiber 1200
Dr / 200 fil. was blown at a yarn traveling speed of 1000 m / min into a hood adjusted to have an inlet of 90 mm and an outlet of 10 mm.
At this time, a test was conducted by flowing air of 0.40 Nm ³ / min in total weight including the side gun, and the dispersion state of the fibers in the collection web was good. At this time, the average basis weight of the web sheet was 45 g / m ² , and the variation in basis weight was 15.4% in the width direction and 7.3% in the longitudinal direction.

Example 4 Using a rayon fiber 300dr / 150fil., A blown test was conducted under the same conditions as in Example 1. The collected web was a very uniform dispersion of fibers. When the distribution of the areal weight of the sheet was measured, the average areal weight was 30 g / m ² , the variation in areal weight in the width direction was 7.0%, and the variation in areal weight in the longitudinal direction was 6.5%.

Example 5 A blown test was conducted under the same conditions as in Example 1 except that polyarylate fiber 250 dr / 50 fil. Was used and the hood size was 40 mm at the inlet and 8.0 mm at the outlet. As in the other examples, the blown fibers were well opened at the place where they left the hood, and were evenly blown. The collected sheet-like web had an average areal weight of 25 g / m ² , a variation in areal weight in the width direction of 11.2%, and a variation in areal weight in the longitudinal direction of 8.5%.

[0018]

As is apparent from the detailed description of the embodiments given above, according to the method of the present invention, an air gun composed of multiple weights for ejecting untwisted open continuous multifilament fiber bundles together with compressed air flow. And side guns that inject only compressed air flow at both ends are lined up and sprayed onto a collection conveyor, and when collecting, a plane plate is surrounded on all four sides downstream of the gun row consisting of the air gun and side guns. A hood, which is adjusted so that the slit width thereof is narrowed, is arranged from the inlet to the outlet, and the untwisted fiber bundle is jetted and passed together with the compressed air flow. At this time, due to the uniformity of the wind speed distribution in the hood due to the morphological characteristics of the hood and the swinging effect in the hood width direction on the spread fiber bundle that basically consists of fiber groups, the spread fiber filament from the adjacent air gun is It is possible to collect long fiber filament webs which are entangled with each other and have a small basis weight variation in the web width direction. A single row of air guns can obtain a web with a low basis weight fluctuation rate, and there is no need to use multiple air gun rows that are out of phase as a set, so there is no need for fine adjustment for phase fluctuations over time. When installed, any gun row can be used according to the purpose of use of the web and the degree of freedom in operation is great. The filament web collected in the form of a sheet can be formed into a long-fiber nonwoven fabric by appropriate adhesion or entanglement.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus used for producing a continuous filament web of the present invention.

2 is a side view of the device shown in FIG. 1. FIG.

[Explanation of symbols] 1. Opened untwisted continuous fiber bundle 2. Air gun 2a. High pressure air inlet 3. Side gun 3a. High pressure air inlet 4. Hood 4a. Hood entrance width 4b. Hood exit width 5. Collection net 6. Collection web 7. Suction device

Claims (2)

[Claims] 1. When manufacturing a non-woven web from untwisted continuous multifilament fiber bundles, an air gun consisting of multiple spindles for injecting the opened fiber bundles together with a compressed air stream and only the compressed air stream are injected at both ends thereof. A side gun is arranged in a line, and a hood, which is surrounded by a flat plate on all four sides and is adjusted so that its slit width becomes narrower from the entrance to the exit, is arranged in the hood from the air gun. Inject and pass the untwisted fiber bundle together with the compressed air flow so that the open fiber filaments from the adjacent air guns are entangled with each other,
A method for producing a non-woven web, comprising collecting on a moving collecting conveyor. 2. The method for manufacturing a nonwoven web according to claim 1, wherein a hood having an inlet width of 10 mm or more and 100 mm or less and an outlet width of 5 mm or more and 10 mm or less is used.